On the positronium spin conversion reactions caused by some macrocyclic Co II complexes

NASA Astrophysics Data System (ADS)

Fantola-Lazzarini, Anna L.; Lazzarini, Ennio

2002-08-01

The rate constants, kCR, of ortho- into para-positronium ( o-Ps→ p-Ps) spin conversion reactions, CR, caused by the high-spin [Co IIsep] 2+, [Co IIdinosar] 2+ and [Co IIdiamsar] 2+ macrocyclic complexes and also by high-spin [Co II sen] 2+ tripod complex were measured at several temperatures. The delocalizations, β, of Co II unpaired electrons, promoted by the mentioned ligands, were determined by using the previously established correlations between kCR and the electron delocalization β of unpaired metal electrons. β is given by the ratio between the Racah inter-electronic repulsion parameters of complexes, B, and that of the free ions, B0. The β values are compared with those of the Co II complexes with en (1,2-ethanediamine), pn (1,2 propanediamine) and dien (2,2' diamino diethylamine) ligands. The kCR rate constants are also compared with those of the Ps oxidation reactions, OR, promoted by the corresponding Co III complexes. It is concluded that, unlike OR's, the CR's do not occur by formation of hepta-coordinate adducts with Ps atoms.

EPR and ESE of CuS4 complex in Cu(dmit)2: g-Factor and hyperfine splitting correlation in tetrahedral Cu-sulfur complexes

NASA Astrophysics Data System (ADS)

Hoffmann, Stanisław K.; Goslar, Janina; Lijewski, Stefan; Zalewska, Alina

2013-11-01

Pseudotetrahedral CuS4 complexes of Cu(dmit)2 compound in DMF solution were studied by EPR, UV-Vis and electron spin echo methods. After rapid freezing at 77 K a good glassy state is formed and the CuS4 complex has a D2d symmetry of a compressed tetrahedron with xy ground state and spin-Hamiltonian parameters g|| = 2.089, g⊥ = 2.026, A|| = 146 × 10-4 cm-1 and A⊥ = 30 × 10-4 cm-1. The complex is not deformed in the glassy state and is very rigid as indicated by the echo detected spectrum and by electron spin relaxation which is governed by reorientations of methyl groups of surrounding DMF molecules as shown by electron spin echo envelope modulation (ESEEM) spectrum. The g|| and A|| of Cu(dmit)2 and other CuS4 complexes collected in Peisach-Blumberg correlation diagram were analyzed using extended Molecular Orbital theory. We explain why the correlation line for copper-sulfur complexes has larger slope compared to the CuO4 and CuN4 tetrahedra. Along the correlation line the delocalization of unpaired electron density onto ligand is constant and varies from β = 0.78-0.83 for g|| in the range 2.06-2.10 of correlation diagram. The slope of the line is determined by the product of MO-coefficients αc1, where α is a parameter characterizing delocalization of unpaired electron in x2-y2 and c1 < 1 is a mixing parameter decreasing when 4p contribution grows. We found, unexpectedly, that αc1≈0.7 for all CuS4 complexes suggesting a correlation between degree of tetrahedral deformation and MO-parameters. MO-coefficients for Cu(dmit)2 are α = 0.753, β = 0.752 and c1 = 0.930 confirming a strong delocalization of unpaired electron in xy and x2-y2 orbitals.

Theoretical study on the magnetic moments formation in Ta-doped anatase TiO2

NASA Astrophysics Data System (ADS)

Bupu, A.; Majidi, M. A.; Rusydi, A.

2017-04-01

We present a theoretical study on Ti-vacancy induced ferromagnetism in Ta-doped anatase TiO2. Experimental study of Ti1-x Ta x O2 thin film has shown that Ti-vacancies (assisted by Ta doping) induce the formation of localized magnetic moment around it, then, the observed ferromagnetism is caused by the alignment of localized magnetic moments through Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. In this study, we focus on the formation of the localized magnetic moments in this system. We hypothesize that on a unit cell, Ti-vacancy has caused four electrons from the surrounding oxygen atoms to become unpaired. These unpaired electrons then arrange themselves into a configuration with a non-zero net magnetic moment. To examine our hypothesis, we construct a Hamiltonian of the four unpaired electrons, incorporating the Coulomb intra- and inter-orbital interactions, in matrix form. Using a set of chosen parameter values, we diagonalize the Hamiltonian to get the eigenstates and eigenvalues, then, with the resulting eigenstates, we calculate the magnetic moment, μ, by obtaining the expectation value of the square of total spin operator. Our calculation results show that in the ground state, provided that the ratio of parameters satisfies some criterion, μ ≈ 4μ B , corresponding to the four electron spins being almost perfectly aligned, can be achieved. Further, as long as we keep the Coulomb intra-orbital interaction between 0.5 and 1 eV, we find that μ ≈ 4μ B is robust up to far above room temperature. Our results demonstrate that Ti vacancies in anatase TiO2 can form very stable localized magnetic moments.

The world as viewed by and with unpaired electrons.

PubMed

Eaton, Sandra S; Eaton, Gareth R

2012-10-01

Recent advances in electron paramagnetic resonance (EPR) include capabilities for applications to areas as diverse as archeology, beer shelf life, biological structure, dosimetry, in vivo imaging, molecular magnets, and quantum computing. Enabling technologies include multifrequency continuous wave, pulsed, and rapid scan EPR. Interpretation is enhanced by increasingly powerful computational models. Copyright © 2012 Elsevier Inc. All rights reserved.

The Demonstration of the Feasibility of the Tuning and Stimulation of Nuclear Radiation.

DTIC Science & Technology

1988-10-31

line, or the center of a resonance pattern, is called the isomer shift. It is due to the electrostatic interaction of the nucleus with the electron ...magnetic moment due to the presence of unpaired electrons , the material is either paramagnetic or ferromagnetic. In paramagnetic materials these moments...capture and fission.4,5,8 A very fertile interdisciplinary area of nuclear quantum electronics 7 appeared to be developing, encouraged by the

Current status of free radicals and electronically excited metastable species as high energy propellants

NASA Technical Reports Server (NTRS)

Rosen, G.

1973-01-01

A survey is presented of free radicals and electronically excited metastable species as high energy propellants for rocket engines. Nascent or atomic forms of diatomic gases are considered free radicals as well as the highly reactive diatomic triatomic molecules that posess unpaired electrons. Manufacturing and storage problems are described, and a review of current experimental work related to the manufacture of atomic hydrogen propellants is presented.

Biochemistry of free radicals: from electrons to tissues.

PubMed

Boveris, A

1998-01-01

Free radicals are chemical species with an unpaired electron in the outer valence orbitals. The unpaired electron makes them paramagnetic (physics) and relatively reactive (chemistry). The free radicals that are normal metabolites in aerobic biological systems have varied reactivities, ranging from the high reactivity of hydroxyl radical (t1/2 = 10(-9) s) to the low reactivity of melanins (t1/2 = days). The univalent reduction of oxygen that takes place in mammalian organs produces superoxide radicals at a rate of about 2% of the total oxygen uptake. The primary production of superoxide radicals sustains a free radical chain reaction involving a series of reactive oxygen species (hydrogen peroxide, hydroxyl and peroxyl radical and singlet oxygen). Nitric oxide is almost unreactive as free radical except for its termination reaction with superoxide radical to yield the strong oxidant peroxynitrite. Nitric oxide also reacts with ubiquinol in a redox reaction, with cytochrome oxidase competitively with oxygen, and oxymyoglobin and oxyhemoglobin displacing oxygen. Septic shock and endotoxemia produce muscle dysfunction and oxidative stress due to increased steady state concentrations of reactive oxygen and nitrogen species.

Dynamic nuclear polarisation via the integrated solid effect II: experiments on naphthalene-h8 doped with pentacene-d14

NASA Astrophysics Data System (ADS)

Eichhorn, T. R.; van den Brandt, B.; Hautle, P.; Henstra, A.; Wenckebach, W. Th.

2014-07-01

In dynamic nuclear polarisation (DNP), also called hyperpolarisation, a small amount of unpaired electron spins is added to the sample containing the nuclear spins, and the polarisation of these unpaired electron spins is transferred to the nuclear spins by means of a microwave field. Traditional DNP polarises the electron spin of stable paramagnetic centres by cooling down to low temperature and applying a strong magnetic field. Then weak continuous wave microwave fields are used to induce the polarisation transfer. Complicated cryogenic equipment and strong magnets can be avoided using short-lived photo-excited triplet states that are strongly aligned in the optical excitation process. However, a much faster transfer of the electron spin polarisation is needed and pulsed DNP methods like nuclear orientation via electron spin locking (NOVEL) and the integrated solid effect (ISE) are used. To describe the polarisation transfer with the strong microwave fields in NOVEL and ISE, the usual perturbation methods cannot be used anymore. In the previous paper, we presented a theoretical approach to calculate the polarisation transfer in ISE. In the present paper, the theory is applied to the system naphthalene-h8 doped with pentacene-d14 yielding the photo-excited triplet states and compared with experimental results.

Well-Known Mediators of Selective Oxidation with Unknown Electronic Structure: Metal-Free Generation and EPR Study of Imide-N-oxyl Radicals.

PubMed

Krylov, Igor B; Kompanets, Mykhailo O; Novikova, Katerina V; Opeida, Iosip O; Kushch, Olga V; Shelimov, Boris N; Nikishin, Gennady I; Levitsky, Dmitri O; Terent'ev, Alexander O

2016-01-14

Nitroxyl radicals are widely used in chemistry, materials sciences, and biology. Imide-N-oxyl radicals are subclass of unique nitroxyl radicals that proved to be useful catalysts and mediators of selective oxidation and CH-functionalization. An efficient metal-free method was developed for the generation of imide-N-oxyl radicals from N-hydroxyimides at room temperature by the reaction with (diacetoxyiodo)benzene. The method allows for the production of high concentrations of free radicals and provides high resolution of their EPR spectra exhibiting the superhyperfine structure from benzene ring protons distant from the radical center. An analysis of the spectra shows that, regardless of the electronic effects of the substituents in the benzene ring, the superhyperfine coupling constant of an unpaired electron with the distant protons at positions 4 and 5 of the aromatic system is substantially greater than that with the protons at positions 3 and 6 that are closer to the N-oxyl radical center. This is indicative of an unusual character of the spin density distribution of the unpaired electron in substituted phthalimide-N-oxyl radicals. Understanding of the nature of the electron density distribution in imide-N-oxyl radicals may be useful for the development of commercial mediators of oxidation based on N-hydroxyimides.

Identification of the substrate radical intermediate derived from ethanolamine during catalysis by ethanolamine ammonia-lyase.

PubMed

Bender, Güneş; Poyner, Russell R; Reed, George H

2008-10-28

Rapid-mix freeze-quench (RMFQ) methods and electron paramagnetic resonance (EPR) spectroscopy have been used to characterize the steady-state radical in the deamination of ethanolamine catalyzed by adenosylcobalamin (AdoCbl)-dependent ethanolamine ammonia-lyase (EAL). EPR spectra of the radical intermediates formed with the substrates, [1-13C]ethanolamine, [2-13C]ethanolamine, and unlabeled ethanolamine were acquired using RMFQ trapping methods from 10 ms to completion of the reaction. Resolved 13C hyperfine splitting in EPR spectra of samples prepared with [1-13C]ethanolamine and the absence of such splitting in spectra of samples prepared with [2-13C]ethanolamine show that the unpaired electron is localized on C1 (the carbinol carbon) of the substrate. The 13C splitting from C1 persists from 10 ms throughout the time course of substrate turnover, and there was no evidence of a detectable amount of a product like radical having unpaired spin on C2. These results correct an earlier assignment for this radical intermediate [Warncke, K., et al. (1999) J. Am. Chem. Soc. 121, 10522-10528]. The EPR signals of the substrate radical intermediate are altered by electron spin coupling to the other paramagnetic species, cob(II)alamin, in the active site. The dipole-dipole and exchange interactions as well as the 1-13C hyperfine splitting tensor were analyzed via spectral simulations. The sign of the isotropic exchange interaction indicates a weak ferromagnetic coupling of the two unpaired electrons. A Co2+-radical distance of 8.7 A was obtained from the magnitude of the dipole-dipole interaction. The orientation of the principal axes of the 13C hyperfine splitting tensor shows that the long axis of the spin-bearing p orbital on C1 of the substrate radical makes an angle of approximately 98 degrees with the unique axis of the d(z2) orbital of Co2+.

In Vivo Imaging of Tissue Physiological Function using EPR Spectroscopy | NCI Technology Transfer Center | TTC

Cancer.gov

Electron paramagnetic resonance (EPR) is a technique for studying chemical species that have one or more unpaired electrons.  The current invention describes Echo-based Single Point Imaging (ESPI), a novel EPR image formation strategy that allows in vivo imaging of physiological function.  The National Cancer Institute's Radiation Biology Branch is seeking statements of capability or interest from parties interested in in-licensing an in vivo imaging using Electron paramagnetic resonance (EPR) to measure active oxygen species.

Electronic and Spatial Structures of Water-Soluble Dinitrosyl Iron Complexes with Thiol-Containing Ligands Underlying Their Ability to Act as Nitric Oxide and Nitrosonium Ion Donors

PubMed Central

Vanin, Anatoly F.; Burbaev, Dosymzhan Sh.

2011-01-01

The ability of mononuclear dinitrosyl iron commplexes (M-DNICs) with thiolate ligands to act as NO donors and to trigger S-nitrosation of thiols can be explain only in the paradigm of the model of the [Fe+(NO+)2] core ({Fe(NO)2}7 according to the Enemark-Feltham classification). Similarly, the {(RS−)2Fe+(NO+)2}+ structure describing the distribution of unpaired electron density in M-DNIC corresponds to the low-spin (S = 1/2) state with a d7 electron configuration of the iron atom and predominant localization of the unpaired electron on MO(dz2) and the square planar structure of M-DNIC. On the other side, the formation of molecular orbitals of M-DNIC including orbitals of the iron atom, thiolate and nitrosyl ligands results in a transfer of electron density from sulfur atoms to the iron atom and nitrosyl ligands. Under these conditions, the positive charge on the nitrosyl ligands diminishes appreciably, the interaction of the ligands with hydroxyl ions or with thiols slows down and the hydrolysis of nitrosyl ligands and the S-nitrosating effect of the latter are not manifested. Most probably, the S-nitrosating effect of nitrosyl ligands is a result of weak binding of thiolate ligands to the iron atom under conditions favoring destabilization of M-DNIC. PMID:22505886

Electronic and spatial structures of water-soluble dinitrosyl iron complexes with thiol-containing ligands underlying their ability to act as nitric oxide and nitrosonium ion donors.

PubMed

Vanin, Anatoly F; Burbaev, Dosymzhan Sh

2011-01-01

The ability of mononuclear dinitrosyl iron commplexes (M-DNICs) with thiolate ligands to act as NO donors and to trigger S-nitrosation of thiols can be explain only in the paradigm of the model of the [Fe(+)(NO(+))(2)] core ({Fe(NO)(2)}(7) according to the Enemark-Feltham classification). Similarly, the {(RS(-))(2)Fe(+)(NO(+))(2)}(+) structure describing the distribution of unpaired electron density in M-DNIC corresponds to the low-spin (S = 1/2) state with a d(7) electron configuration of the iron atom and predominant localization of the unpaired electron on MO(d(z2)) and the square planar structure of M-DNIC. On the other side, the formation of molecular orbitals of M-DNIC including orbitals of the iron atom, thiolate and nitrosyl ligands results in a transfer of electron density from sulfur atoms to the iron atom and nitrosyl ligands. Under these conditions, the positive charge on the nitrosyl ligands diminishes appreciably, the interaction of the ligands with hydroxyl ions or with thiols slows down and the hydrolysis of nitrosyl ligands and the S-nitrosating effect of the latter are not manifested. Most probably, the S-nitrosating effect of nitrosyl ligands is a result of weak binding of thiolate ligands to the iron atom under conditions favoring destabilization of M-DNIC.

75 FR 52756 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-27

... for evaluation of chemical species having unpaired electrons such as free radicals and transition.... Durnin J, Micheli J Jr, Eberly JH. Diffraction-free beams. Phys Rev Lett. 1987 Apr 13;58(15):1499-1501. 2... quantify pharmaco-kinetics and metabolic degradation kinetics of bioactive and redox sensitive free...

Angle-Resolved Photoemission of Solvated Electrons in Sodium-Doped Clusters.

PubMed

West, Adam H C; Yoder, Bruce L; Luckhaus, David; Saak, Clara-Magdalena; Doppelbauer, Maximilian; Signorell, Ruth

2015-04-16

Angle-resolved photoelectron spectroscopy of the unpaired electron in sodium-doped water, methanol, ammonia, and dimethyl ether clusters is presented. The experimental observations and the complementary calculations are consistent with surface electrons for the cluster size range studied. Evidence against internally solvated electrons is provided by the photoelectron angular distribution. The trends in the ionization energies seem to be mainly determined by the degree of hydrogen bonding in the solvent and the solvation of the ion core. The onset ionization energies of water and methanol clusters do not level off at small cluster sizes but decrease slightly with increasing cluster size.

Electron paramagnetic resonance of gamma-irradiated single crystals of 3-nitroacetanilide

NASA Astrophysics Data System (ADS)

Aşik, Biray

2008-06-01

The electron paramagnetic resonance of single crystals of 3-nitroacetanilide has been observed and analyzed for different orientations of the crystal in the magnetic field, after being damaged at 300 K by γ-irradiation. The crystals have been investigated between 123 and 300 K. The spectra were found to be temperature independent. The irradiation of 3-nitroacetanilide by γ-rays produces radicals at the nitrogen atoms in the molecule. The principal values of the hyperfine coupling tensor of the unpaired electron and the principal values of the g-tensor were determined.

Spin-exchange effects in elastic electron-radical collisions

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

Fujimoto, M. M.; Michelin, S. E.; Iga, I.

2006-01-15

This work presents a theoretical investigation on the spin-exchange effects in the low-energy elastic electron-C{sub 2}O radical collisions. Spin-polarization differential and integral cross sections calculated in the 1-10-eV energy range are reported. Our calculation has shown that the exchange between the scattering and unpaired target electron is strongly influenced by the occurrence of shape resonances. More specifically, our calculated rotationally summed spin-polarization fractions show significant deviation from unity in the resonance region. An analysis of the contributions from individual rotational transitions is also made.

Computation of Chemical Shifts for Paramagnetic Molecules: A Laboratory Experiment for the Undergraduate Curriculum

ERIC Educational Resources Information Center

Pritchard, Benjamin P.; Simpson, Scott; Zurek, Eva; Autschbach, Jochen

2014-01-01

A computational experiment investigating the [superscript 1]H and [superscript 13]C nuclear magnetic resonance (NMR) chemical shifts of molecules with unpaired electrons has been developed and implemented. This experiment is appropriate for an upper-level undergraduate laboratory course in computational, physical, or inorganic chemistry. The…

Incomplete Combustion of Hydrogen: Trapping a Reaction Intermediate

ERIC Educational Resources Information Center

Mattson, Bruce; Hoette, Trisha

2007-01-01

The combustion of hydrogen in air is quite complex with at least 28 mechanistic steps and twelve reaction species. Most of the species involved are radicals (having unpaired electrons) in nature. Among the various species generated, a few are stable, including hydrogen peroxide. In a normal hydrogen flame, the hydrogen peroxide goes on to further…

Fingerprints of single nuclear spin energy levels using STM - ENDOR

NASA Astrophysics Data System (ADS)

Manassen, Yishay; Averbukh, Michael; Jbara, Moamen; Siebenhofer, Bernhard; Shnirman, Alexander; Horovitz, Baruch

2018-04-01

We performed STM-ENDOR experiments where the intensity of one of the hyperfine components detected in ESR-STM is recorded while an rf power is irradiated into the tunneling junction and its frequency is swept. When the latter frequency is near a nuclear transition a dip in ESR-STM signal is observed. This experiment was performed in three different systems: near surface SiC vacancies where the electron spin is coupled to a next nearest neighbor 29Si nucleus; Cu deposited on Si(111)7x7 surface, where the unpaired electron of the Cu atom is coupled to the Cu nucleus (63Cu, 65Cu) and on Tempo molecules adsorbed on Au(111), where the unpaired electron is coupled to a Nitrogen nucleus (14N). While some of the hyperfine values are unresolved in the ESR-STM data due to linewidth we find that they are accurately determined in the STM-ENDOR data including those from remote nuclei, which are not detected in the ESR-STM spectrum. Furthermore, STM-ENDOR can measure single nuclear Zeeman frequencies, distinguish between isotopes through their different nuclear magnetic moments and detect quadrupole spectra. We also develop and solve a Bloch type equation for the coupled electron-nuclear system that facilitates interpretation of the data. The improved spectral resolution of STM - ENDOR opens many possibilities for nanometric scale chemical analysis.

Fingerprints of single nuclear spin energy levels using STM - ENDOR.

PubMed

Manassen, Yishay; Averbukh, Michael; Jbara, Moamen; Siebenhofer, Bernhard; Shnirman, Alexander; Horovitz, Baruch

2018-04-01

We performed STM-ENDOR experiments where the intensity of one of the hyperfine components detected in ESR-STM is recorded while an rf power is irradiated into the tunneling junction and its frequency is swept. When the latter frequency is near a nuclear transition a dip in ESR-STM signal is observed. This experiment was performed in three different systems: near surface SiC vacancies where the electron spin is coupled to a next nearest neighbor 29 Si nucleus; Cu deposited on Si(111)7x7 surface, where the unpaired electron of the Cu atom is coupled to the Cu nucleus ( 63 Cu, 65 Cu) and on Tempo molecules adsorbed on Au(111), where the unpaired electron is coupled to a Nitrogen nucleus ( 14 N). While some of the hyperfine values are unresolved in the ESR-STM data due to linewidth we find that they are accurately determined in the STM-ENDOR data including those from remote nuclei, which are not detected in the ESR-STM spectrum. Furthermore, STM-ENDOR can measure single nuclear Zeeman frequencies, distinguish between isotopes through their different nuclear magnetic moments and detect quadrupole spectra. We also develop and solve a Bloch type equation for the coupled electron-nuclear system that facilitates interpretation of the data. The improved spectral resolution of STM - ENDOR opens many possibilities for nanometric scale chemical analysis. Copyright © 2018 Elsevier Inc. All rights reserved.

Long-range crystalline order in spicules from the calcareous sponge Paraleucilla magna (Porifera, Calcarea).

PubMed

Rossi, Andre L; Campos, Andrea P C; Barroso, Madalena M S; Klautau, Michelle; Archanjo, Bráulio S; Borojevic, Radovan; Farina, Marcos; Werckmann, Jacques

2014-09-01

We investigated the ultrastructure and crystallographic orientation of spicules from the calcareous sponge Paraleucilla magna (subclass Calcaronea) by transmission and scanning electron microscopy using two different methods of sample preparation: ultramicrotomy and focused ion beam (FIB). It was found that the unpaired actine from the spicules was oriented in the [211] zone axis. The plane that contains the unpaired actine and divides symmetrically the paired actines is the (-120). This plane is a mirror plane of the hexagonal lattice system. All the spicule types analyzed presented the same crystallographic orientation. Electron nanodiffraction maps from 4μm×4μm regions prepared by FIB showed disorientation of <2° between diffraction patterns obtained from neighbor regions, indicating the presence of a unique, highly aligned calcite crystalline phase. Among the eight FIB sections obtained, four presented high pore density. In one section perpendicular to the actine axis pores were observed only in the center of the spicule aligned in a circular pattern and surrounded by a faint circular contour with a larger radius. The presence of amorphous carbon representative of organic molecules detected by electron energy loss spectroscopy was correlated neither with porosity nor with specific lattice planes. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

Henstra, A.; Wenckebach, W. Th.

1991-02-01

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

Using skype as an alternative for residency selection interviews.

PubMed

Edje, Louito; Miller, Christine; Kiefer, Jacklyn; Oram, David

2013-09-01

Residency interviews can place significant time and financial burdens on applicants. To determine whether the use of Skype as a screening tool during interview season in a family medicine residency is cost-effective and time-efficient for the applicant and the residency program. We surveyed 2 groups of medical students during interviews for our family medicine program. Thirty-two students were interviewed via our face-to-face, traditional interview (TI) process, and 10 students, the second group, who did not meet the program's standard interview selection criteria for TI, underwent our Skype interview (SI) process. Using an unpaired t test, we found that the applicants' costs of an SI were significantly less than a TI, $566 (95% confidence interval [CI] $784-$349, P < .001). Direct cash savings plus indirect salary savings to the program were $5,864, with a time savings of 7 interview days. Three of the applicants who were participants in the SI limb of the study were in our final rank order list. For interviewing in family medicine residencies, use of Skype may be a cost-effective and time-efficient screening tool for both the applicant and the program. Alternate uses of SI may include the time-sensitive, postmatch Supplemental Offer and Acceptance Program.

Using Skype as an Alternative for Residency Selection Interviews

PubMed Central

Edje, Louito; Miller, Christine; Kiefer, Jacklyn; Oram, David

2013-01-01

Background Residency interviews can place significant time and financial burdens on applicants. Objective To determine whether the use of Skype as a screening tool during interview season in a family medicine residency is cost-effective and time-efficient for the applicant and the residency program. Methods We surveyed 2 groups of medical students during interviews for our family medicine program. Thirty-two students were interviewed via our face-to-face, traditional interview (TI) process, and 10 students, the second group, who did not meet the program's standard interview selection criteria for TI, underwent our Skype interview (SI) process. Results Using an unpaired t test, we found that the applicants' costs of an SI were significantly less than a TI, $566 (95% confidence interval [CI] $784–$349, P < .001). Direct cash savings plus indirect salary savings to the program were $5,864, with a time savings of 7 interview days. Three of the applicants who were participants in the SI limb of the study were in our final rank order list. Conclusions For interviewing in family medicine residencies, use of Skype may be a cost-effective and time-efficient screening tool for both the applicant and the program. Alternate uses of SI may include the time-sensitive, postmatch Supplemental Offer and Acceptance Program. PMID:24404318

Ground and excited states of CaSH through electron propagator calculations

NASA Astrophysics Data System (ADS)

Ortiz, J. V.

1990-05-01

Electron propagator calculations of electron affinities of CaSH + produce ground and excited state energies at the optimized, C s minimum of the neutral ground state and at a C ∞v geometry. Feynman-Dyson amplitudes (FDAs) describe the distribution of the least bound electron in various states. The neutral ground state differs from the cation by the occupation of a one-electron state dominated by Ca s functions. Described by FDAs with Ca-S π pseudosymmetry, corresponding excited states have unpaired electrons in orbitals displaying interference between Ca p and d functions. Above these lies a σ pseudosymmetry FDA with principal contributions from Ca d functions. Two FDAs with σ pseudosymmetry follow. Higher excited states exhibit considerable delocalization onto S.

Impact of a structured surgical curriculum on ophthalmic resident cataract surgery complication rates.

PubMed

Rogers, Gina M; Oetting, Thomas A; Lee, Andrew G; Grignon, Connie; Greenlee, Emily; Johnson, A Tim; Beaver, Hilary A; Carter, Keith

2009-11-01

To determine whether institution of a structured surgical curriculum for ophthalmology residents decreased the rate of sentinel surgical complications. Veterans Affairs Medical Center, Des Moines, Iowa, USA. A retrospective review was performed of third-year ophthalmic resident quality-assurance surgical outcomes data at a single residency-training site from 1998 to 2008. The primary outcome measure was defined as a sentinel event; that is, a posterior capsule tear (with or without vitreous loss) or vitreous loss (from any cause) occurring during a resident-performed case. The study population was divided into 2 groups. Group 1 comprised surgical cases of residents trained before the surgical curriculum change (academic years 1998 to 2003) and Group 2, surgical cases of residents trained with the enhanced curriculum (academic years 2004 to 2008). Data from 1 year (academic year 2003 to 2004) were excluded because the transition to the enhanced curriculum occurred during that period. The data were analyzed and adjusted for surgical experience. In Group 1 (before institution of surgical curriculum), there were 823 cases with 59 sentinel complications. In Group 2 (after institution of surgical curriculum), there were 1009 cases with 38 sentinel complications. There was a statistically significant reduction in the sentinel complication rate, from 7.17% before the curriculum changes to 3.77% with the enhanced curriculum (P = .001, unpaired 2-tailed t test). Implementation of a structured surgical curriculum resulted in a statistically significant reduction in sentinel event complications, even after adjusting for surgical experience.

Probing influence of rare earth ions (Er3+, Dy3+ and Gd3+) on structural, magnetic and optical properties of magnetite nanoparticles

NASA Astrophysics Data System (ADS)

Jain, Richa; Luthra, Vandna; Gokhale, Shubha

2018-06-01

Fe3-xRExO4 (RE = Er, Dy and Gd) nanoparticles with x varying from 0 to 0.1 were synthesized using co-precipitation method. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and UV-Vis spectroscopy techniques. TEM images reveal round shaped particles of ∼8-14 nm diameter in case of undoped magnetite (Fe3O4) nanoparticles whereas there is evolution of rod like structures by the doping of RE ions with aspect ratio in the range of 6-16. The room temperature saturation magnetization (Ms) values show gradual increase with doping till a critical doping level which is found to depend on the ionic radius of dopant ion (x = 0.01 for Er, 0.03 for Dy and 0.04 for Gd). There is a variation in the maximum value of saturation magnetization which is directly proportional to the number of unpaired 4f electrons in the dopant element. Low temperature magnetization study, carried out at 5 K and 120 K reveal an increase in the value of Ms as well as coercivity. The direct bandgaps calculated from UV-Visible data are found to decrease with increasing number of unpaired electrons in the dopant ions.

Translation of the assembling trajectory by preorganisation: a study of the magnetic properties of 1D polymeric unpaired electrons immobilised on a discrete nanoscopic scaffold.

PubMed

Praveen, Vakayil K; Yamamoto, Yohei; Fukushima, Takanori; Tsunobuchi, Yoshihide; Nakabayashi, Koji; Ohkoshi, Shin-ichi; Kato, Kenichi; Takata, Masaki; Aida, Takuzo

2015-01-25

A nitronyl nitroxide (NN)-appended hexabenzocoronene (HBC(NN)), when allowed to coassemble with bis(hexafluoroacetylacetonato)cobalt(II), forms a coaxial nanotubular architecture featuring NN-Co(II) coordinated copolymer chains immobilised on the outer and inner nanotube surfaces. Upon lowering the temperature, this nanotube has enhanced magnetic susceptibility below 10 K.

Enzymatic cellulose oxidation is linked to lignin by long-range electron transfer

PubMed Central

Westereng, Bjørge; Cannella, David; Wittrup Agger, Jane; Jørgensen, Henning; Larsen Andersen, Mogens; Eijsink, Vincent G.H.; Felby, Claus

2015-01-01

Enzymatic oxidation of cell wall polysaccharides by lytic polysaccharide monooxygenases (LPMOs) plays a pivotal role in the degradation of plant biomass. While experiments have shown that LPMOs are copper dependent enzymes requiring an electron donor, the mechanism and origin of the electron supply in biological systems are only partly understood. We show here that insoluble high molecular weight lignin functions as a reservoir of electrons facilitating LPMO activity. The electrons are donated to the enzyme by long-range electron transfer involving soluble low molecular weight lignins present in plant cell walls. Electron transfer was confirmed by electron paramagnetic resonance spectroscopy showing that LPMO activity on cellulose changes the level of unpaired electrons in the lignin. The discovery of a long-range electron transfer mechanism links the biodegradation of cellulose and lignin and sheds new light on how oxidative enzymes present in plant degraders may act in concert. PMID:26686263

Experimental investigation on the microscopic structure of intrinsic paramagnetic point defects in amorphous silicon dioxide

NASA Astrophysics Data System (ADS)

Buscarino, G.

2007-11-01

In the present Ph.D. Thesis we report an experimental investigation on the effects of gamma- and beta-ray irradiation and of subsequent thermal treatment on many types of a-SiO2 materials, differing in the production methods, OH- and Al-content, and oxygen deficiencies. Our main objective is to gain further insight on the microscopic structures of the E'_gamma, E'_delta, E'_alpha and triplet paramagnetic centers, which are among the most important and studied class of radiation induced intrinsic point defects in a-SiO2. To pursue this objective, we use prevalently the EPR spectroscopy. In particular, our work is focused on the properties of the unpaired electrons wave functions involved in the defects, and this aspect is mainly investigated through the study of the EPR signals originating from the interaction of the unpaired electrons with 29Si magnetic nuclei (with nuclear spin I=1/2 and natural abundance 4.7 %). In addition, in some cases of interest, OA measurements are also performed with the aim to further characterize the electronic properties of the defects. Furthermore, due to its relevance for electronics application, the charge state of the defects is investigated by looking at the processes responsible for the generation of the defects of interest. Once these information were gained, the possible sites that can serve as precursors for defects formation are deduced, with the definitive purpose to obtain in the future more radiation resistant a-SiO2 materials in which the deleterious effects connected with the point defects are significantly reduced.

Does a new surgical residency program increase operating room times?

PubMed

Castillo, Alvaro; Zarak, Alberto; Kozol, Robert A

2013-01-01

Our country faces a shortage of surgeons; hence, we may anticipate the development of new surgery residencies. Therefore, the question of the effect of a new program on operating room times (ORT) is important. Our primary aim was to compare ORT of 3 common procedures done by attendings alone vs ORT of cases with residents. We queried records of 1458 patients from the JFK Medical Center database for laparoscopic cholecystectomy, open inguinal hernia repair, and laparoscopic appendectomy from July 2010 to July 2012. We divided the sample into 2 groups: "attending alone" (2010-2011) and "with residents" (2011-2012). The ORT was calculated by "Cut time" and "Close time," as recorded in the OR. ORT for both groups was calculated using the unpaired t test. Of the total number of patients, 778 underwent laparoscopic cholecystectomy, 407 underwent open inguinal hernia repair, and 273 underwent laparoscopic appendectomy; of these, 620, 315, and 211 procedures, respectively, were done by the attending alone and 158, 92, and 62, respectively, were done with residents. Differences in ORT for the 3 types of surgery were statistically significant (p < 0.001). There was no statistical significance when comparing the first half with the second half of the academic year for residents' ORT. Resident involvement increases ORT. Cost analysis considering OR time and anesthesia time vs federal funding for Graduate Medical Education is complicated. The benefit of new programs in diminishing the shortage of surgeons cannot be underestimated. © 2013 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Structural, electronic and magnetic properties of Pr-based filled skutterudites: A first principle study

NASA Astrophysics Data System (ADS)

Yadav, Priya; Nautiyal, Shashank; Verma, U. P.

2018-04-01

Ternary skutterudites materials exhibit good electronic properties due to the unpaired d- and f- electrons of the transition and rare-earth metals, respectively. In this communication, we have performed the structural optimization of Pr-based filled skutterudite (PrCo4P12) for the first time and obtained the electronic band structure, density of states and magnetic moments by using the full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). Our obtained magnetic moment of PrCo4P12 is ˜ 1.8 µB in which main contribution is due to Pr atom. Behavior of this material is metallic and it is most stable in body centered cubic (BCC) structure.

Mechanism of mismatch recognition revealed by human MutSβ bound to unpaired DNA loops

PubMed Central

Gupta, Shikha; Gellert, Martin; Yang, Wei

2011-01-01

DNA mismatch repair corrects replication errors, thus reducing mutation rates and microsatellite instability. Genetic defects in this pathway cause Lynch Syndrome and various cancers in humans. Binding of a mispaired or unpaired base by bacterial MutS and eukaryotic MutSα is well characterized. We report here crystal structures of human MutSβ complexed with DNA containing insertion-deletion loops (IDL) of 2, 3, 4, or 6 unpaired nucleotides. In contrast to eukaryotic MutSα and bacterial MutS, which bind the base of a mismatched nucleotide, MutSβ binds three phosphates in an IDL. DNA is severely bent at the IDL; unpaired bases are flipped out into the major groove and partially exposed to solvent. A normal downstream basepair can become unpaired; thereby a single unpaired base can be converted to an IDL of 2 nucleotides and recognized by MutSβ. The C-terminal dimerization domains form an integral part of the MutS structure and coordinate asymmetrical ATP hydrolysis by Msh2 and Msh3 with mismatch binding to signal for repair. PMID:22179786

In situ oligomerization of 2-(thiophen-3-yl)acetate intercalated into Zn{sub 2}Al layered double hydroxide

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

Tronto, Jairo, E-mail: jairotronto@ufv.br; Pinto, Frederico G.; Costa, Liovando M. da

2015-01-15

A layered double hydroxide (LDH) with cation composition Zn{sub 2}Al was intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers. To achieve in situ polymerization and/or oligomerization of the intercalated monomers, soft thermal treatments were carried out, and subsequent hybrid LDH materials were analyzed by means of several characterization techniques using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), {sup 13}C CP–MAS nuclear magnetic resonance (NMR), electron spin resonance (EPR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP–OES), and elemental analysis. PXRD analysis suggested that the intercalated monomers formed a bilayer. Thermalmore » treatment of the hybrid LDH assembly above 120 °C provokes partially the breakdown of the layered structure, generating the phase zincite. EPR results indicated that vicinal monomers (oligomerization) were bound to each other after hydrothermal or thermal treatment, leading to a polaron response characteristic of electron conductivity localized on a restricted number of thiophene-based monomer segments. Localized unpaired electrons exist in the material and interact with the {sup 27}Al nuclei of the LDH layers by superhyperfine coupling. These unpaired electrons also interact with the surface of ZnO (O{sup 2−} vacancies), formed during the thermal treatments. - Graphical abstract: We synthesized a layered double hydroxide (LDH) with cation composition Zn{sub 2}Al, intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers, by coprecipitation at constant pH. We thermally treated the material, to achieve in situ polymerization and/or oligomerization of the intercalated monomers. - Highlights: • A Zn{sub 2}Al–LDH was intercalated with 2-(thiophen-3-yl)acetate monomers. • To achieve in situ oligomerization of the monomers, thermal treatments were made. • Thermal treatment above 120 °C causes partially breakdown of the LDH structure. • ESR results indicated a polaron response characteristic of electron conductivity.« less

Streptococcus pyogenes outbreak in a long-term care facility.

PubMed

Harkness, G A; Bentley, D W; Mottley, M; Lee, J

1992-06-01

Although outbreaks involving Streptococcus pyogenes have been uncommon among the elderly population, recent reports suggest that this organism is an important nosocomial pathogen among institutionalized older patients and carries significant morbidity and mortality. An outbreak of S. pyogenes, type M12, T12, occurred in a large long-term care institution serving the ill and chronically disabled. The outbreak involved 14 residents of the intermediate care facility and lasted for 4 months. A prospective epidemiologic investigation was initiated at the onset of the outbreak. Pertinent clinical and demographic information regarding both residents and personnel was obtained by interview, review of medical and surveillance records, and examination of patients for lesions. Cultures were obtained within 24 hours of symptom onset from those with characteristic clinical symptoms. Unpaired convalescent sera were tested for group A streptococcal extracellular antigens by a rapid hemagglutination slide test. Control measures included active surveillance of residents and staff for suspicious clinical syndromes, transfer of high-risk patients, elimination of a common seating area, and improved handwashing and hygiene measures. The attack rate was 7.5%, with 64.3% of these patients residing on one unit. S. pyogenes was isolated from eight residents, 5 residents had a characteristic syndrome and an elevated streptozyme hemagglutination titer of 400, and 1 resident died within hours of having cellulitis of the groin. Clinical syndromes included cellulitis, pharyngitis, bronchitis, pneumonia, and septicemia. Seven residents required acute care; two residents died within 3 weeks of the onset, yielding a case fatality rate of 14.3%. The major means of transmission appeared to be direct contact between residents, although transmission from an infected staff member may have accounted for some cases. The hypothesis of long-term colonization was supported by the extended times between infections. The severity of illness and the apparent transmission through direct contact between residents warrants (1) early detection of infected lesions, (2) recognition of invasive illness, (3) prompt effective treatment, and (4) surveillance for S. pyogenes infections among residents and personnel.

Observing electron localization in a dissociating H2+ molecule in real time

PubMed Central

Xu, H.; Li, Zhichao; He, Feng; Wang, X.; Atia-Tul-Noor, A.; Kielpinski, D.; Sang, R. T.; Litvinyuk, I. V.

2017-01-01

Dissociation of diatomic molecules with odd number of electrons always causes the unpaired electron to localize on one of the two resulting atomic fragments. In the simplest diatomic molecule H2+ dissociation yields a hydrogen atom and a proton with the sole electron ending up on one of the two nuclei. That is equivalent to breaking of a chemical bond—the most fundamental chemical process. Here we observe such electron localization in real time by performing a pump–probe experiment. We demonstrate that in H2+ electron localization is complete in just 15 fs when the molecule’s internuclear distance reaches 8 atomic units. The measurement is supported by a theoretical simulation based on numerical solution of the time-dependent Schrödinger equation. This observation advances our understanding of detailed dynamics of molecular dissociation. PMID:28621332

Oxygen radicals as key mediators in neurological disease: fact or fiction?

PubMed

Halliwell, B

1992-01-01

A free radical is any species capable of independent existence that contains one or more unpaired electrons. Free radicals and other reactive oxygen species are frequently proposed to be involved in the pathology of several neurological disorders. Criteria for establishing such involvement are presented. Development of new methods for measuring oxidative damage should enable elucidation of the precise role of reactive oxygen species in neurological disorders.

The fate of H atom adducts to 3'-uridine monophosphate.

PubMed

Wang, Ran; Zhang, Ru Bo; Eriksson, Leif A

2010-07-29

The stabilities of the adducts deriving from H free radical addition to the O2, O4, and C5 positions of 3'-uridine monophosphate (3'UMP) are studied by the hybrid density functional B3LYP approach. Upon H atom addition at the O2 position, a concerted low-barrier proton-transfer process will initially occur, followed by the potential ruptures of the N-glycosidic or beta-phosphate bonds. The rupture barriers are strongly influenced by the rotational configuration of the phosphate group at the 3' terminal, and are influenced by bulk solvation effects. The O4-H adduct has the highest thermal stability, as the localization of the unpaired electron does not enable cleavage of either the C1'-N1 or the C3'-O(P) bonds. For the most stable adduct, with H atom added to the C5 position, the rate-controlled step is the H2'a abstraction by the C6 radical site, after which the subsequent strand rupture reactions proceed with low barriers. The main unpaired electron densities are presented for the transient species. Combined with previous results, it is concluded that the H atom adducts are more facile to drive the strand scission rather than N-glycosidic bond ruptures within the nucleic acid bases.

Mimicking the magnetic properties of rare earth elements using superatoms.

PubMed

Cheng, Shi-Bo; Berkdemir, Cuneyt; Castleman, A W

2015-04-21

Rare earth elements (REs) consist of a very important group in the periodic table that is vital to many modern technologies. The mining process, however, is extremely damaging to the environment, making them low yield and very expensive. Therefore, mimicking the properties of REs in a superatom framework is especially valuable but at the same time, technically challenging and requiring advanced concepts about manipulating properties of atom/molecular complexes. Herein, by using photoelectron imaging spectroscopy, we provide original idea and direct experimental evidence that chosen boron-doped clusters could mimic the magnetic characteristics of REs. Specifically, the neutral LaB and NdB clusters are found to have similar unpaired electrons and magnetic moments as their isovalent REs (namely Nd and Eu, respectively), opening up the great possibility in accomplishing rare earth mimicry. Extension of the superatom concept into the rare earth group not only further shows the power and advance of this concept but also, will stimulate more efforts to explore new superatomic clusters to mimic the chemistry of these heavy atoms, which will be of great importance in designing novel building blocks in the application of cluster-assembled nanomaterials. Additionally, based on these experimental findings, a novel "magic boron" counting rule is proposed to estimate the numbers of unpaired electrons in diatomic LnB clusters.

Radiation effects in x-irradiated hydroxy compounds

NASA Astrophysics Data System (ADS)

Budzinski, Edwin E.; Potter, William R.; Box, Harold C.

1980-01-01

Radiation effects are compared in single crystals of xylitol, sorbitol, and dulcitol x-irradiated at 4.2 °K. In xylitol and dulcitol, but not in sorbitol, a primary oxidation product is identified as an alkoxy radical. ENDOR measurements detected three proton hyperfine couplings associated with the alkoxy ESR absorption, one of which is attributed to a proton three bond lengths removed from the seat of unpaired spin density. Intermolecular trapping of electrons is observed in all three crystals. ENDOR measurements were made of the hyperfine couplings between the trapped electron and the hydroxy protons forming the trap.

Cognitive Stimulation of Elderly Residents in Social Protection Centers in Cartagena, 2014.

PubMed

Melguizo Herrera, Estela; Bertel De La Hoz, Anyel; Paternina Osorio, Diego; Felfle Fuentes, Yurani; Porto Osorio, Leidy

To determine the effectiveness of a program of cognitive stimulation of the elderly residents in Social Protection Centers in Cartagena, 2014. Quasi-experimental study with pre and post tests in control and experimental groups. A sample of 37 elderly residents in Social Protection Centers participated: 23 in the experimental group and 14 in the control group. A survey and a mental evaluation test (Pfeiffer) were applied. The experimental group participated in 10 sessions of cognitive stimulation. The paired t-test showed statistically significant differences in the Pfeiffer test, pre and post intervention, compared to the experimental group (P=.0005). The unpaired t-test showed statistically significant differences in Pfeiffer test results to the experimental and control groups (P=.0450). The analysis of the main components showed that more interrelated variables were: age, diseases, number of errors and test results; which were grouped around the disease variable, with a negative association. The intervention demonstrated a statistically significant improvement in cognitive functionality of the elderly. Nursing can lead this type of intervention. It should be studied further to strengthen and clarify these results. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Mechanism of mismatch recognition revealed by human MutS[beta] bound to unpaired DNA loops

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

Gupta, Shikha; Gellert, Martin; Yang, Wei

2012-04-17

DNA mismatch repair corrects replication errors, thus reducing mutation rates and microsatellite instability. Genetic defects in this pathway cause Lynch syndrome and various cancers in humans. Binding of a mispaired or unpaired base by bacterial MutS and eukaryotic MutS{alpha} is well characterized. We report here crystal structures of human MutS{beta} in complex with DNA containing insertion-deletion loops (IDL) of two, three, four or six unpaired nucleotides. In contrast to eukaryotic MutS{alpha} and bacterial MutS, which bind the base of a mismatched nucleotide, MutS{beta} binds three phosphates in an IDL. DNA is severely bent at the IDL; unpaired bases are flippedmore » out into the major groove and partially exposed to solvent. A normal downstream base pair can become unpaired; a single unpaired base can thereby be converted to an IDL of two nucleotides and recognized by MutS{beta}. The C-terminal dimerization domains form an integral part of the MutS structure and coordinate asymmetrical ATP hydrolysis by Msh2 and Msh3 with mismatch binding to signal for repair.« less

Electron spin relaxation governed by Raman processes both for Cu2+ ions and carbonate radicals in KHCO3 crystals: EPR and electron spin echo studies

NASA Astrophysics Data System (ADS)

Hoffmann, Stanislaw K.; Goslar, Janina; Lijewski, Stefan

2012-08-01

EPR studies of Cu2+ and two free radicals formed by γ-radiation were performed for KHCO3 single crystal at room temperature. From the rotational EPR results we concluded that Cu2+ is chelated by two carbonate molecules in a square planar configuration with spin-Hamiltonian parameters g|| = 2.2349 and A|| = 18.2 mT. Free radicals were identified as neutral HOCOrad with unpaired electron localized on the carbon atom and a radical anion CO3·- with unpaired electron localized on two oxygen atoms. The hyperfine splitting of the EPR lines by an interaction with a single hydrogen atom of HOCOrad was observed with isotropic coupling constants ao = 0.31 mT. Two differently oriented radical sites were identified in the crystal unit cell. Electron spin-lattice relaxation measured by electron spin echo methods shows that both Cu2+ and free radicals relax via two-phonon Raman processes with almost the same relaxation rate. The temperature dependence of the relaxation rate 1/T1 is well described with the effective Debye temperature ΘD = 175 K obtained from a fit to the Debye-type phonon spectrum. We calculated a more realistic Debye temperature value from available elastic constant values of the crystal as ΘD = 246 K. This ΘD-value and the Debye phonon spectrum approximation give a much worse fit to the experimental results. Possible contributions from a local mode or an optical mode are considered and it is suggested that the real phonon spectrum should be used for the relaxation data interpretation. It is unusual that free radicals in KHCO3 relax similarly to the well localized Cu2+ ions, which suggests a small destruction of the host crystal lattice by the ionizing irradiation allowing well coupling between radical and lattice dynamics.

Low-temperature spin dynamics of a valence bond glass in Ba2YMoO6

NASA Astrophysics Data System (ADS)

de Vries, M. A.; Piatek, J. O.; Misek, M.; Lord, J. S.; Rønnow, H. M.; Bos, J.-W. G.

2013-04-01

We carried out ac magnetic susceptibility measurements and muon spin relaxation spectroscopy on the cubic double perovskite Ba2YMoO6, down to 50 mK. Below ∼1 K the muon relaxation is typical of a magnetic insulator with a spin-liquid type ground state, i.e. without broken symmetries or frozen moments. However, the ac susceptibility revealed a dilute-spin-glass-like transition below ∼1 K. Antiferromagnetically coupled Mo5+ 4d1 electrons in triply degenerate t2g orbitals are in this material arranged in a geometrically frustrated fcc lattice. Bulk magnetic susceptibility data has previously been interpreted in terms of a freezing to a heterogeneous state with non-magnetic sites where 4d1 electrons have paired in spin-singlets dimers, and residual unpaired Mo5+ 4d1 electron spins. Based on the magnetic heat capacity data it has been suggested that this heterogeneity is the result of kinetic constraints intrinsic to the physics of the pure system (possibly due to topological overprotection) leading to a self-induced glass of valence bonds between neighbouring 4d1 electrons. The muon spin relaxation (μSR) unambiguously points to a heterogeneous state with a static arrangement of unpaired electrons in a background of (valence bond) dimers between the majority of Mo5+ 4d electrons. The ac susceptibility data indicate that the residual magnetic moments freeze into a dilute-spin-glass-like state. This is in apparent contradiction with the muon-spin decoupling at 50 mK in fields up to 200 mT, which indicates that, remarkably, the time scale of the field fluctuations from the residual moments is ∼5 ns. Comparable behaviour has been observed in other geometrically frustrated magnets with spin-liquid-like behaviour and the implications of our observations on Ba2YMoO6 are discussed in this context.

Moderate Bacterial Etching Allows Scalable and Clean Delamination of g-C3N4 with Enriched Unpaired Electrons for Highly Improved Photocatalytic Water Disinfection.

PubMed

Kang, Shifei; Huang, Wei; Zhang, Lu; He, Maofen; Xu, Suyun; Sun, Di; Jiang, Xia

2018-04-25

Delamination treatment is crucial in promoting the activity of bulk graphitic carbon nitride (g-C 3 N 4 ). However, most of the currently used methods of exfoliating bulk g-C 3 N 4 to achieve g-C 3 N 4 thin layers suffer from low yield and environmental pollution. Herein, we developed a facile bacterial etching approach for the preparation of high-quality g-C 3 N 4 nanosheets by exfoliating bulk g-C 3 N 4 under room temperature. Morphology and physicochemical characterizations show that the bacteria-treated g-C 3 N 4 (BT-CN) samples, especially BT-CN-2d, have a lamina-like two-dimensional (2D) in-plane porous structure, a significantly enlarged specific surface area (82.61 m 2 g -1 ), and a remarkable narrow band gap (2.11 eV). X-ray photoelectron spectroscopy and electron paramagnetic resonance spectra confirm the dramatic enrichment of unpaired electron in the BT-CN-2d g-C 3 N 4 nanosheets. EIS spectra and photocurrent tests indicate the fast electron transportation. As a result, the representative BT-CN-2d g-C 3 N 4 photocatalyst shows an optimal visible light-driven photocatalytic performance in water disinfection (fourfold higher than bulk g-C 3 N 4 ), as well as good cycle stability. This moderate and clean bacterial etching process can be realized in tens of gram scale in the laboratory and should be readily extended to kilogram scale. The present work provides fundamental knowledge about the scalable production of high-quality g-C 3 N 4 by bioengineering method, offering extendable availability for designing and fabricating other functional 2D materials.

Progress towards an electron electric dipole moment search in Europium-Barium Titanates

NASA Astrophysics Data System (ADS)

Eckel, Stephen; Sushkov, Alexander; Lamoreaux, Steven

2012-06-01

We report on recent progress on a search for the electron's electric dipole moment (eEDM) using solid- state Eu0.5Ba0.5TiO3. This material has many desirable properties including ferroelectricity below 200 K and paramagnetism above 1.8 K. When the sample has a non-zero electric polarization, the seven unpaired 4f electrons of the Eu^2+ ions in the lattice feel a large effective electric field of order 10 MV/cm in the direction of the polarization. This causes the electron spins to align with the electric polarization and generate a magnetization, which is measured using DC SQUID magnetometers. We will detail measurements of systematic effects along with recent results toward a measurement of the eEDM.

Potential for Biodegradation of the Alkaline Hydrolysis End Products of TNT and RDX

DTIC Science & Technology

2007-11-01

Bellco Glass, Inc. (Vineland, NJ). The stainless steel , deflected point needles used in sparging (18 G, 6 in. and 12 in.) were manufactured by Popper and...12 Figure 4. Gas sparging of anaerobic cultures showing the direction of flow of the CO2- free carrier gas through the sample...determine if any reaction components exhibited unpaired electron spins, which would indicate a free radical. EPR results suggested that a single

Reduction of protein radicals by GSH and ascorbate: potential biological significance.

PubMed

Gebicki, Janusz M; Nauser, Thomas; Domazou, Anastasia; Steinmann, Daniel; Bounds, Patricia L; Koppenol, Willem H

2010-11-01

The oxidation of proteins and other macromolecules by radical species under conditions of oxidative stress can be modulated by antioxidant compounds. Decreased levels of the antioxidants glutathione and ascorbate have been documented in oxidative stress-related diseases. A radical generated on the surface of a protein can: (1) be immediately and fully repaired by direct reaction with an antioxidant; (2) react with dioxygen to form the corresponding peroxyl radical; or (3) undergo intramolecular long range electron transfer to relocate the free electron to another amino acid residue. In pulse radiolysis studies, in vitro production of the initial radical on a protein is conveniently made at a tryptophan residue, and electron transfer often leads ultimately to residence of the unpaired electron on a tyrosine residue. We review here the kinetics data for reactions of the antioxidants glutathione, selenocysteine, and ascorbate with tryptophanyl and tyrosyl radicals as free amino acids in model compounds and proteins. Glutathione repairs a tryptophanyl radical in lysozyme with a rate constant of (1.05±0.05)×10(5) M(-1) s(-1), while ascorbate repairs tryptophanyl and tyrosyl radicals ca. 3 orders of magnitude faster. The in vitro reaction of glutathione with these radicals is too slow to prevent formation of peroxyl radicals, which become reduced by glutathione to hydroperoxides; the resulting glutathione thiyl radical is capable of further radical generation by hydrogen abstraction. Although physiologically not significant, selenoglutathione reduces tyrosyl radicals as fast as ascorbate. The reaction of protein radicals formed on insulin, β-lactoglobulin, pepsin, chymotrypsin and bovine serum albumin with ascorbate is relatively rapid, competes with the reaction with dioxygen, and the relatively innocuous ascorbyl radical is formed. On the basis of these kinetics data, we suggest that reductive repair of protein radicals may contribute to the well-documented depletion of ascorbate in living organisms subjected to oxidative stress.

ESR dating of barite in sea-floor hydrothermal sulfide deposits at Okinawa Trough

NASA Astrophysics Data System (ADS)

Fujiwara, T.; Toyoda, S.; Uchida, A.; Ishibashi, J.; Nakai, S.; Takamasa, A.

2013-12-01

The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). With this aspect, Okumura et al. (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite to obtain preliminary ages, while Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. ESR is a method to observe radicals having unpaired electrons. As natural radiation creates unpaired electrons in minerals, the age is deduced by dividing the natural radiation dose (obtained from the amount of unpaired electrons) by the dose rate which is estimated by the amount of environmental radioactive elements. The samples were taken by the research cruises, NT12-10 and NT11-20 and NT12-06 operated by JAMSTEC from Hatoma, Yoron, Izena, North Iheya, and Yonaguni IV Knolls of Okinawa Trough. The blocks of sulfide deposits were cut into pieces, and about 2.0g was crushed. The samples were soaked in 12M hydrochloric acid, left for approximately 24 hours. Then, 13M nitric acid was added. Finally, after rinsing in distilled water, the sample was filtered and dried. Impurities were removed by handpicking. A X-ray diffraction study was made to confirm that the grains are pure barite. After γ-ray irradiation at Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, they were measured at room temperature with an ESR spectrometer (JES-PX2300) with a microwave power of 1mW, and the magnetic field modulation amplitude of 0.1mT. The equivalent natural radiation doses were obtained from the increase of ESR signal intensity of SO3- by irradiation. The bulk Ra concentration was measured by the low background pure Ge gamma ray spectrometer. Assuming that Ra is populated only in barite, the dose rate was calculated with the alpha effectiveness of 0.043 (Toyoda et al., 2012), where the decay of Ra (a half life of 1600 years) was also taken into account. The dating results indicate that the ages are, Yron Knoll < Hatoma Knoll ≒ North Iheya Knoll < Izena Knoll. This order of ages is consistent with the development of the hydrothermal vent ecosystem estimated by observed landscape.. The results of U-Th dating for these samples will also be presented.

Competing pseudogap and impurity effects on the normal-state specific heat properties of cuprate superconductors

NASA Astrophysics Data System (ADS)

Dzhumanov, S.; Karimboev, E. X.

2014-07-01

In this paper, we show that the pseudogap in the excitation spectra of high-Tc cuprates together with the impurity phase and charge inhomogeneity plays key roles in determining the essential features of their anomalous specific heat properties observed above Tc. We consider the doped cuprate superconductor as a multi-carrier model system (which consists of intrinsic and extrinsic polarons and pre-formed bosonic Cooper pairs) and study the competing pseudogap and impurity effects on the normal-state electronic specific heat of high-Tc cuprates taking into account charge inhomogeneities. We argue that unconventional electron-phonon interactions are responsible for the precursor Cooper pairing in the polaronic band below a mean-field temperature T∗ and the existence of a pseudogap above Tc in the cuprates. The electronic specific heat Ce(T) of doped cuprates below T∗ is calculated taking into account three contributions coming from the excited components of Cooper pairs, the ideal Bose-gas of incoherent Cooper pairs and the unpaired carriers in the impurity band. Above T∗, two contributions to Ce(T) coming from the unpaired intrinsic and extrinsic polarons are calculated within the two-component degenerate Fermi-gas model. By comparing our results with the experimental Ce(T) data obtained for La- and Y-based cuprates, we find that the observed behaviors of Ce(T) (below and above T∗) are similar to the calculated results for Ce(T) and the BCS-type jumps of Ce(T) at T∗ may be depressed by the impurity effects and may become more or less pronounced BCS-type anomalies in Ce(T) .

The Relationship Between Chemical Structure and Dielectric Properties of Plasma-Enhanced Chemical Vapor Deposited Polymer Thin Films (Postprint)

DTIC Science & Technology

2007-01-01

C6H6, Aldrich Co., liquid , high performance liquid chromatography (HPLC) grade with a purity of 99.9%) and octafluorocyclobutane (C4F8, OFCB...attributed to the lack of molecular mobility (confined by the crosslinking) and low ionic polarization of the molecular structures [6]. The frequency...in dielectric constant at low frequencies can be traced to orientational polarizations of trapped free radicals, unpaired electron sites, oligomeric

Spin microscope based on optically detected magnetic resonance

DOEpatents

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

2010-06-29

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

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2007-12-11

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

Spin microscope based on optically detected magnetic resonance

DOEpatents

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

2010-07-13

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

Spin microscope based on optically detected magnetic resonance

DOEpatents

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

2009-10-27

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

Tuning exchange interactions in organometallic semiconductors

NASA Astrophysics Data System (ADS)

Rawat, Naveen; Manning, Lane W.; Hua, Kim-Ngan; Headrick, Randall L.; Cherian, Judy G.; Bishop, Michael M.; McGill, Stephen A.; Furis, Madalina I.

2015-09-01

Organic semiconductors are emerging as a leading area of research as they are expected to overcome limitations of inorganic semiconductor devices for certain applications where low cost manufacturing, device transparency in the visible range or mechanical flexibility are more important than fast switching times. Solution processing methods produce thin films with millimeter sized crystalline grains at very low cost manufacturing prices, ideally suited for optical spectroscopy investigations of long range many-body effects in organic systems. To this end, we synthesized an entire family of organosoluble 3-d transition metal Pc's and successfully employed a novel solution-based pen-writing deposition technique to fabricate long range ordered thin films of mixtures of metal-free (H2Pc) molecule and organometallic phthalocyanines (MPc's). Our previous studies on the parent MPc crystalline thin films identified different electronic states mediating exchange interactions in these materials. This understanding of spin-dependent exchange interaction between delocalized π-electrons with unpaired d spins enabled the further tuning of these interactions by mixing CoPc and H2Pc in different ratios ranging from 1:1 to 1000:1 H2Pc:MPc. The magnitude of the exchange is also tunable as a function of the average distance between unpaired spins in these materials. Furthermore, high magnetic field (B < 25T) MCD and magneto-photoluminescence show evidence of spin-polarized band-edge excitons in the same materials.

Zeroth order regular approximation approach to electric dipole moment interactions of the electron.

PubMed

Gaul, Konstantin; Berger, Robert

2017-07-07

A quasi-relativistic two-component approach for an efficient calculation of P,T-odd interactions caused by a permanent electric dipole moment of the electron (eEDM) is presented. The approach uses a (two-component) complex generalized Hartree-Fock and a complex generalized Kohn-Sham scheme within the zeroth order regular approximation. In applications to select heavy-elemental polar diatomic molecular radicals, which are promising candidates for an eEDM experiment, the method is compared to relativistic four-component electron-correlation calculations and confirms values for the effective electric field acting on the unpaired electron for RaF, BaF, YbF, and HgF. The calculations show that purely relativistic effects, involving only the lower component of the Dirac bi-spinor, are well described by treating only the upper component explicitly.

Zeroth order regular approximation approach to electric dipole moment interactions of the electron

NASA Astrophysics Data System (ADS)

Gaul, Konstantin; Berger, Robert

2017-07-01

A quasi-relativistic two-component approach for an efficient calculation of P ,T -odd interactions caused by a permanent electric dipole moment of the electron (eEDM) is presented. The approach uses a (two-component) complex generalized Hartree-Fock and a complex generalized Kohn-Sham scheme within the zeroth order regular approximation. In applications to select heavy-elemental polar diatomic molecular radicals, which are promising candidates for an eEDM experiment, the method is compared to relativistic four-component electron-correlation calculations and confirms values for the effective electric field acting on the unpaired electron for RaF, BaF, YbF, and HgF. The calculations show that purely relativistic effects, involving only the lower component of the Dirac bi-spinor, are well described by treating only the upper component explicitly.

Structural and thermodynamic analysis of modified nucleosides in self-assembled DNA cross-tiles.

PubMed

Hakker, Lauren; Marchi, Alexandria N; Harris, Kimberly A; LaBean, Thomas H; Agris, Paul F

2014-01-01

DNA Holliday junctions are important natural strand-exchange structures that form during homologous recombination. Immobile four-arm junctions, analogs to Holliday junctions, have been designed to self-assemble into cross-tile structures by maximizing Watson-Crick base pairing and fixed crossover points. The cross-tiles, self-assembled from base pair recognition between designed single-stranded DNAs, form higher order lattice structures through cohesion of self-associating sticky ends. These cross-tiles have 16 unpaired nucleosides in the central loop at the junction of the four duplex stems. The importance of the centralized unpaired nucleosides to the structure's thermodynamic stability and self-assembly is unknown. Cross-tile DNA nanostructures were designed and constructed from nine single-stranded DNAs with four shell strands, four arms, and a central loop containing 16 unpaired bases. The 16 unpaired bases were either 2'-deoxyribothymidines, 2'-O-methylribouridines, or abasic 1',2'-dideoxyribonucleosides. Thermodynamic profiles and structural base-stacking contributions were assessed using UV absorption spectroscopy during thermal denaturation and circular dichroism spectroscopy, respectively, and the resulting structures were observed by atomic force microscopy. There were surprisingly significant changes in the thermodynamic and structural properties of lattice formation as a result of altering only the 16 unpaired, centralized nucleosides. The 16 unpaired 2'-O-methyluridines were stabilizing and produced uniform tubular structures. In contrast, the abasic nucleosides were destabilizing producing a mixture of structures. These results strongly indicate the importance of a small number of centrally located unpaired nucleosides within the structures. Since minor modifications lead to palpable changes in lattice formation, DNA cross-tiles present an easily manipulated structure convenient for applications in biomedical and biosensing devices.

Apomorphine conditioning and sensitization: the paired/unpaired treatment order as a new major determinant of drug conditioned and sensitization effects.

PubMed

de Matos, Liana Wermelinger; Carey, Robert J; Carrera, Marinete Pinheiro

2010-09-01

Repeated treatments with psychostimulant drugs generate behavioral sensitization. In the present study we employed a paired/unpaired protocol to assess the effects of repeated apomorphine (2.0 mg/kg) treatments upon locomotion behavior. In the first experiment we assessed the effects of conditioning upon apomorphine sensitization. Neither the extinction of the conditioned response nor a counter-conditioning procedure in which we paired an inhibitory treatment (apomorphine 0.05 mg/kg) with the previously established conditioned stimulus modified the sensitization response. In the second experiment, we administered the paired/unpaired protocol in two phases. In the second phase, we reversed the paired/unpaired protocol. Following the first phase, the paired group alone exhibited conditioned locomotion in the vehicle test and a sensitization response. In the second phase, the initial unpaired group which received 5 paired apomorphine trials during the reversal phase did not develop a conditioned response but developed a potentiated sensitization response. This disassociation of the conditioned response from the sensitization response is attributed to an apomorphine anti-habituation effect that can generate a false positive Pavlovian conditioned response effect. The potentiated sensitization response induced by the treatment reversal protocol points to an important role for the sequential experience of the paired/unpaired protocol in behavioral sensitization. 2010 Elsevier Inc. All rights reserved.

On the nature of Ni···Ni interaction in a model dimeric Ni complex.

PubMed

Kamiński, Radosław; Herbaczyńska, Beata; Srebro, Monika; Pietrzykowski, Antoni; Michalak, Artur; Jerzykiewicz, Lucjan B; Woźniak, Krzysztof

2011-06-07

A new dinuclear complex (NiC(5)H(4)SiMe(2)CHCH(2))(2) (2) was prepared by reacting nickelocene derivative [(C(5)H(4)SiMe(2)CH=CH(2))(2)Ni] (1) with methyllithium (MeLi). Good quality crystals were subjected to a high-resolution X-ray measurement. Subsequent multipole refinement yielded accurate description of electron density distribution. Detailed inspection of experimental electron density in Ni···Ni contact revealed that the nickel atoms are bonded and significant deformation of the metal valence shell is related to different populations of the d-orbitals. The existence of the Ni···Ni bond path explains the lack of unpaired electrons in the complex due to a possible exchange channel.

NATO-ASI on ’Sensors for Environment, Health and Security: Advanced Materials and Technologies’ Held in Limoges, France 16-27 Septermber 2007.

DTIC Science & Technology

2008-09-18

molecular oxygen – singlet oxygen (SO). According to the quantum theory , the spin configuration of the lowest energy state with unpaired electrons in...in applications spanning from environmental and health monitoring to security. Lectures on advanced theories and modeling of the sensing mechanisms...10:15 Marie-Isabelle BARATON and Pavel KASHKAROV Welcome address Introduction to the Advanced Study Institute 10:15 – 10:30 Welcome address by

Defect Induced Electronic Structure of Uranofullerene

PubMed Central

Dai, Xing; Cheng, Cheng; Zhang, Wei; Xin, Minsi; Huai, Ping; Zhang, Ruiqin; Wang, Zhigang

2013-01-01

The interaction between the inner atoms/cluster and the outer fullerene cage is the source of various novel properties of endohedral metallofullerenes. Herein, we introduce an adatom-type spin polarization defect on the surface of a typical endohedral stable U2@C60 to predict the associated structure and electronic properties of U2@C61 based on the density functional theory method. We found that defect induces obvious changes in the electronic structure of this metallofullerene. More interestingly, the ground state of U2@C61 is nonet spin in contrast to the septet of U2@C60. Electronic structure analysis shows that the inner U atoms and the C ad-atom on the surface of the cage contribute together to this spin state, which is brought about by a ferromagnetic coupling between the spin of the unpaired electrons of the U atoms and the C ad-atom. This discovery may provide a possible approach to adapt the electronic structure properties of endohedral metallofullerenes. PMID:23439318

Associations with resident physicians' early adoption of electronic cigarettes for smoking cessation.

PubMed

Egnot, Eric; Jordan, Kim; Elliott, John O

2017-06-01

Use of the electronic cigarette for nicotine delivery has increased dramatically in recent years. Information continues to emerge on its role as a smoking cessation aid, but little is known about resident physician use of the device in clinical practice. In 2015, an electronic survey was administered to resident physicians in one healthcare system in Columbus, Ohio. The survey included questions about personal smoking exposure, knowledge, beliefs, attitudes about electronic cigarettes and early adoption of electronic cigarettes with patients. Data were dichotomised based on a 'stages of change' model that assessed resident physician adoption of electronic cigarettes for therapeutic use. Data were analysed through χ 2 tests and logistic regression using ORs and 95% CIs. Of 338 residents, 142 (42%) responded. Of all residents, 25 (17.7%) reported that they have been recommending electronic cigarettes to their patients for the past 6 months or longer. In the multivariate model, residents ≥postgraduate year (PGY)-3 (OR=3.68, 95% CI 1.20 to 11.29), peer-reviewed article exposure (OR=6.65, 95% CI 1.56 to 28.38) and the view that addictive potential is definitely or somewhat less than traditional cigarettes (OR=5.05, 95% CI 1.48 to 17.24) were associated with recommendation of electronic cigarettes. Few residents report recommending electronic cigarettes to patients who smoke. These residents consider the electronic cigarette less addicting than traditional cigarettes, supporting harm reduction strategies over strict abstinence. Most residents require further evidence-based education on efficacy and long-term safety of electronic cigarettes before recommending to their patients. 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/.

Room temperature ferromagnetism in Fe-doped semiconductor ZrS2 single crystals

NASA Astrophysics Data System (ADS)

Muhammad, Zahir; Lv, Haifeng; Wu, Chuanqiang; Habib, Muhammad; Rehman, Zia ur; Khan, Rashid; Chen, Shuangming; Wu, Xiaojun; Song, Li

2018-04-01

Two dimensional (2D) layered magnetic materials have obtained much attention due to their intriguing properties with a potential application in the field of spintronics. Herein, room-temperature ferromagnetism with 0.2 emu g‑1 magnetic moment is realized in Fe-doped ZrS2 single crystals of millimeter size, in comparison with diamagnetic behaviour in ZrS2. The electron paramagnetic resonance spectroscopy reveals that 5.2wt% Fe-doping ZrS2 crystal exhibit high spin value of g-factor about 3.57 at room temperature also confirmed this evidence, due to the unpaired electrons created by doped Fe atoms. First principle static electronic and magnetic calculations further confirm the increased stability of long range ferromagnetic ordering and enhanced magnetic moment in Fe-doped ZrS2, originating from the Fe spin polarized electron near the Fermi level.

Multi-level modeling of total ionizing dose in a-silicon dioxide: First principles to circuits

NASA Astrophysics Data System (ADS)

Nicklaw, Christopher J.

Oxygen vacancies have long been known to be the dominant intrinsic defect in amorphous SiO2. They exist, in concentrations dependent on processing conditions, as neutral defects in thermal oxides without usually causing any significant deleterious effects, with some spatial and energy distribution. During irradiation they can capture holes and become positively charged E '-centers, contributing to device degradation. Over the years, a considerable database has been amassed on the dynamics of E' -centers in bulk SiO2 films, and near the interface under different irradiation and annealing conditions. Theoretical calculations so far have revealed the basic properties of prototype oxygen vacancies, primarily as they behave in either a crystalline quartz environment, or in small clusters that serve as a substitute for a real amorphous structure. To date at least three categories of E'-centers, existing at or above room temperature, have been observed in SiO2. The unifying feature is an unpaired electron on a threefold coordinated silicon atom, having the form O3 ≡ Si·. Feigl et al. identified the E'1 -center in crystalline quartz as a trapped hole on an oxygen vacancy, which causes an asymmetrical relaxation, resulting in a paramagnetic center. The unpaired electron in the E'1 -center is localized on the three-fold coordinated Si atoms, while the hole is localized on the other Si atom. Results from an ab initio statistical simulation examination of the behaviors of oxygen vacancies, within amorphous structures, identify a new form of the E'-center, the E'g5 and help in the understanding of the underlying physical mechanisms involved in switched-bias annealing, and electron paramagnetic resonance (EPR) studies. The results also suggest a common border trap, induced by trapped holes in SiO2, is a hole trapped at an oxygen vacancy defect, which can be compensated by an electron, as originally proposed by Lelis and co-workers at Harry Diamond Laboratories. This dissertation provides new insights into the basic mechanisms of a-SiO2 defects, and provides a link between basic mechanisms and Electronic Design Automation (EDA) tools, providing an enhanced design flow for radiation-resistant electronics.

Use of the QR Reader to Provide Real-Time Evaluation of Residents' Skills Following Surgical Procedures.

PubMed

Reynolds, Kellin; Barnhill, Danny; Sias, Jamie; Young, Amy; Polite, Florencia Greer

2014-12-01

A portable electronic method of providing instructional feedback and recording an evaluation of resident competency immediately following surgical procedures has not previously been documented in obstetrics and gynecology. This report presents a unique electronic format that documents resident competency and encourages verbal communication between faculty and residents immediately following operative procedures. The Microsoft Tag system and SurveyMonkey platform were linked by a 2-D QR code using Microsoft QR code generator. Each resident was given a unique code (TAG) embedded onto an ID card. An evaluation form was attached to each resident's file in SurveyMonkey. Postoperatively, supervising faculty scanned the resident's TAG with a smartphone and completed the brief evaluation using the phone's screen. The evaluation was reviewed with the resident and automatically submitted to the resident's educational file. The evaluation system was quickly accepted by residents and faculty. Of 43 residents and faculty in the study, 38 (88%) responded to a survey 8 weeks after institution of the electronic evaluation system. Thirty (79%) of the 38 indicated it was superior to the previously used handwritten format. The electronic system demonstrated improved utilization compared with paper evaluations, with a mean of 23 electronic evaluations submitted per resident during a 6-month period versus 14 paper assessments per resident during an earlier period of 6 months. This streamlined portable electronic evaluation is an effective tool for direct, formative feedback for residents, and it creates a longitudinal record of resident progress. Satisfaction with, and use of, this evaluation system was high.

Use of the QR Reader to Provide Real-Time Evaluation of Residents' Skills Following Surgical Procedures

PubMed Central

Reynolds, Kellin; Barnhill, Danny; Sias, Jamie; Young, Amy; Polite, Florencia Greer

2014-01-01

Background A portable electronic method of providing instructional feedback and recording an evaluation of resident competency immediately following surgical procedures has not previously been documented in obstetrics and gynecology. Objective This report presents a unique electronic format that documents resident competency and encourages verbal communication between faculty and residents immediately following operative procedures. Methods The Microsoft Tag system and SurveyMonkey platform were linked by a 2-D QR code using Microsoft QR code generator. Each resident was given a unique code (TAG) embedded onto an ID card. An evaluation form was attached to each resident's file in SurveyMonkey. Postoperatively, supervising faculty scanned the resident's TAG with a smartphone and completed the brief evaluation using the phone's screen. The evaluation was reviewed with the resident and automatically submitted to the resident's educational file. Results The evaluation system was quickly accepted by residents and faculty. Of 43 residents and faculty in the study, 38 (88%) responded to a survey 8 weeks after institution of the electronic evaluation system. Thirty (79%) of the 38 indicated it was superior to the previously used handwritten format. The electronic system demonstrated improved utilization compared with paper evaluations, with a mean of 23 electronic evaluations submitted per resident during a 6-month period versus 14 paper assessments per resident during an earlier period of 6 months. Conclusions This streamlined portable electronic evaluation is an effective tool for direct, formative feedback for residents, and it creates a longitudinal record of resident progress. Satisfaction with, and use of, this evaluation system was high. PMID:26140128

Transient species involved in catalytic dioxygen/peroxide activation by hemoproteins: possible involvement of protonated Compound I species.

PubMed

Silaghi-Dumitrescu, Radu; Cooper, Chris E

2005-11-07

Interaction of hemoproteins with peroxide leads in several cases to transient formation of ferric peroxo, ferric hydroperoxo, and "high-valent", formally Fev, oxo or hydroxo Compound species. Here, density functional calculations on ferric peroxo, ferric hydroperoxo, Compound and protonated Compound heme active site models are reported. The theoretical results, including calculated isotropic Fermi contact couplings and anisotropic spin dipole couplings, are found to generally correlate well with experimental EPR/ENDOR data. Hydrogen bonding and solvation affect the ferric-peroxo/ferrous-superoxo electromerism. The transition between the two electromers appears smooth, but neither hydrogen bonding to up to two water molecules, nor solvation appear able to dramatically alter the redox state of the superoxo ligand or of the iron. The presence of almost one full unpaired electron on the iron and of one full unpaired electron on the dioxygenic ligand in the "ferric-peroxo" state suggests a possible description of non-protonated "ferric-peroxo" as {ferric-superoxo+porphyrin radical}. Emerging from the DFT data is the possibility that a protonated Compound has already been detected in ENDOR experiments on cytochrome P450. The general feasibility of a protonated Compound in P450 monooxygenases is probed in light of these findings. To encompass the multiple mechanisms available in P450 for substrate oxidation, we define "mechanistic promiscuity" as the feature allowing an enzyme to perform the same reaction, with the same product, using more than one mechanism.

Properties of Transition Metal Doped Alumina

NASA Astrophysics Data System (ADS)

Nykwest, Erik; Limmer, Krista; Brennan, Ray; Blair, Victoria; Ramprasad, Rampi

Crystallographic texture can have profound effects on the properties of a material. One method of texturing is through the application of an external magnetic field during processing. While this method works with highly magnetic systems, doping is required to couple non-magnetic systems with the external field. Experiments have shown that low concentrations of rare earth (RE) dopants in alumina powders have enabled this kind of texturing. The magnetic properties of RE elements are directly related to their f orbital, which can have as many as 7 unpaired electrons. Since d-block elements can have as many as 5 unpaired electrons the effects of substitutional doping of 3d transition metals (TM) for Al in alpha (stable) and theta (metastable) alumina on the local structure and magnetic properties, in addition to the energetic cost, have been calculated by performing first-principles calculations based on density functional theory. This study has led to the development of general guidelines for the magnetic moment distribution at and around the dopant atom, and the dependence of this distribution on the dopant atom type and its coordination environment. It is anticipated that these findings can aid in the selection of suitable dopants help to guide parallel experimental efforts. This project was supported in part by an internship at the Army Research Laboratory, administered by the Oak Ridge Institute for Science and Education, along with a grant of computer time from the DoD High Performance Computing Modernization Program.

Hinge-Like Motions in RNA Kink-Turns: The Role of the Second A-Minor Motif and Nominally Unpaired Bases

PubMed Central

Rázga, Filip; Koča, Jaroslav; Šponer, Jiří; Leontis, Neocles B.

2005-01-01

Kink-turn (K-turn) motifs are asymmetric internal loops found at conserved positions in diverse RNAs, with sharp bends in phosphodiester backbones producing V-shaped structures. Explicit-solvent molecular dynamics simulations were carried out for three K-turns from 23S rRNA, i.e., Kt-38 located at the base of the A-site finger, Kt-42 located at the base of the L7/L12 stalk, and Kt-58 located in domain III, and for the K-turn of human U4 snRNA. The simulations reveal hinge-like K-turn motions on the nanosecond timescale. The first conserved A-minor interaction between the K-turn stems is entirely stable in all simulations. The angle between the helical arms of Kt-38 and Kt-42 is regulated by local variations of the second A-minor (type I) interaction between the stems. Its variability ranges from closed geometries to open ones stabilized by insertion of long-residency waters between adenine and cytosine. The simulated A-minor geometries fully agree with x-ray data. Kt-58 and Kt-U4 exhibit similar elbow-like motions caused by conformational change of the adenosine from the nominally unpaired region. Despite the observed substantial dynamics of K-turns, key tertiary interactions are stable and no sign of unfolding is seen. We suggest that some K-turns are flexible elements mediating large-scale ribosomal motions during the protein synthesis cycle. PMID:15722438

Fluctuations in the electron system of a superconductor exposed to a photon flux

PubMed Central

de Visser, P. J.; Baselmans, J. J. A.; Bueno, J.; Llombart, N.; Klapwijk, T. M.

2014-01-01

In a superconductor, in which electrons are paired, the density of unpaired electrons should become zero when approaching zero temperature. Therefore, radiation detectors based on breaking of pairs promise supreme sensitivity, which we demonstrate using an aluminium superconducting microwave resonator. Here we show that the resonator also enables the study of the response of the electron system of the superconductor to pair-breaking photons, microwave photons and varying temperatures. A large range in radiation power (at 1.54 THz) can be chosen by carefully filtering the radiation from a blackbody source. We identify two regimes. At high radiation power, fluctuations in the electron system caused by the random arrival rate of the photons are resolved, giving a straightforward measure of the optical efficiency (48±8%) and showing an unprecedented detector sensitivity. At low radiation power, fluctuations are dominated by excess quasiparticles, the number of which is measured through their recombination lifetime. PMID:24496036

The effect of electronic health record software design on resident documentation and compliance with evidence-based medicine.

PubMed

Rodriguez Torres, Yasaira; Huang, Jordan; Mihlstin, Melanie; Juzych, Mark S; Kromrei, Heidi; Hwang, Frank S

2017-01-01

This study aimed to determine the role of electronic health record software in resident education by evaluating documentation of 30 elements extracted from the American Academy of Ophthalmology Dry Eye Syndrome Preferred Practice Pattern. The Kresge Eye Institute transitioned to using electronic health record software in June 2013. We evaluated the charts of 331 patients examined in the resident ophthalmology clinic between September 1, 2011, and March 31, 2014, for an initial evaluation for dry eye syndrome. We compared documentation rates for the 30 evidence-based elements between electronic health record chart note templates among the ophthalmology residents. Overall, significant changes in documentation occurred when transitioning to a new version of the electronic health record software with average compliance ranging from 67.4% to 73.6% (p < 0.0005). Electronic Health Record A had high compliance (>90%) in 13 elements while Electronic Health Record B had high compliance (>90%) in 11 elements. The presence of dialog boxes was responsible for significant changes in documentation of adnexa, puncta, proptosis, skin examination, contact lens wear, and smoking exposure. Significant differences in documentation were correlated with electronic health record template design rather than individual resident or residents' year in training. Our results show that electronic health record template design influences documentation across all resident years. Decreased documentation likely results from "mouse click fatigue" as residents had to access multiple dialog boxes to complete documentation. These findings highlight the importance of EHR template design to improve resident documentation and integration of evidence-based medicine into their clinical notes.

Tunable Kondo physics in a carbon nanotube double quantum dot.

PubMed

Chorley, S J; Galpin, M R; Jayatilaka, F W; Smith, C G; Logan, D E; Buitelaar, M R

2012-10-12

We investigate a tunable two-impurity Kondo system in a strongly correlated carbon nanotube double quantum dot, accessing the full range of charge regimes. In the regime where both dots contain an unpaired electron, the system approaches the two-impurity Kondo model. At zero magnetic field the interdot coupling disrupts the Kondo physics and a local singlet state arises, but we are able to tune the crossover to a Kondo screened phase by application of a magnetic field. All results show good agreement with a numerical renormalization group study of the device.

Spectroscopic characterization of the ethyl radical-water complex.

PubMed

Lin, Chen; Finney, Brian A; Laufer, Allan H; Anglada, Josep M; Francisco, Joseph S

2016-10-14

An ab initio investigation has been employed to determine the structural and spectroscopic parameters, such as rotational constants, vibrational frequencies, vertical excitation energies, and the stability of the ethyl-water complex. The ethyl-water complex has a binding energy of 1.15 kcal⋅mol -1 . The interaction takes place between the hydrogen of water and the unpaired electron of the radical. This interaction is found to produce a red shift in the OH stretching bands of water of ca. 84 cm -1 , and a shift of all UV absorption bands to higher energies.

Interoceptive fear conditioning and panic disorder: the role of conditioned stimulus-unconditioned stimulus predictability.

PubMed

Acheson, Dean T; Forsyth, John P; Moses, Erica

2012-03-01

Interoceptive fear conditioning is at the core of contemporary behavioral accounts of panic disorder. Yet, to date only one study has attempted to evaluate interoceptive fear conditioning in humans (see Acheson, Forsyth, Prenoveau, & Bouton, 2007). That study used brief (physiologically inert) and longer-duration (panicogenic) inhalations of 20% CO(2)-enriched air as an interoceptive conditioned (CS) and unconditioned (US) stimulus and evaluated fear learning in three conditions: CS only, CS-US paired, and CS-US unpaired. Results showed fear conditioning in the paired condition, and fearful responding and resistance to extinction in an unpaired condition. The authors speculated that such effects may be due to difficulty discriminating between the CS and the US. The aims of the present study are to (a) replicate and expand this line of work using an improved methodology, and (b) clarify the role of CS-US discrimination difficulties in either potentiating or depotentiating fear learning. Healthy participants (N=104) were randomly assigned to one of four conditions: (a) CS only, (b) contingent CS-US pairings, (c) unpaired CS and US presentations, or (d) an unpaired "discrimination" contingency, which included an exteroceptive discrimination cue concurrently with CS onset. Electrodermal and self-report ratings served as indices of conditioned responding. Consistent with expectation, the paired contingency and unpaired contingencies yielded elevated fearful responding to the CS alone. Moreover, adding a discrimination cue to the unpaired contingency effectively attenuated fearful responding. Overall, findings are consistent with modern learning theory accounts of panic and highlight the role of interoceptive conditioning and unpredictability in the etiology of panic disorder. Copyright © 2011. Published by Elsevier Ltd.

A comparison of procedures for unpairing conditioned reflexive motivating operations.

PubMed

Kettering, Tracy L; Neef, Nancy A; Kelley, Michael E; Heward, William L

2018-03-01

This study compared the effectiveness of two procedures to reduce behavior evoked by a reflexive conditioned motivating operation (CMO-R). Task demands were shown to evoke escape-maintained problem behavior for 4 students with disabilities. Alternative communication responses were taught as an appropriate method to request escape and this treatment combined with extinction for problem behavior led to decreases in problem behavior for all students. A beeping timer was then arranged to temporally precede the task demand to create a CMO-R that evoked communication responses. When data showed that the sound of the timer was functioning as a CMO-R, two methods to reduce behavior evoked by a CMO-R-extinction unpairing and noncontingent unpairing-were evaluated. Results indicated that noncontingent unpairing was an effective method to reduce the evocative effects of the CMO-R. Extinction produced unsystematic effects across participants. Results are discussed in terms of abolishing CMOs and the implications of CMOs. © 2018 Society for the Experimental Analysis of Behavior.

Search for exotic short-range interactions using paramagnetic insulators

DOE PAGES

Chu, Pinghan; Weisman, E.; Liu, C. -Y.; ...

2015-05-26

We describe a proposed experimental search for exotic spin-coupled interactions using a solid-state paramagnetic insulator. The experiment is sensitive to the net magnetization induced by the exotic interaction between the unpaired insulator electrons with a dense, nonmagnetic mass in close proximity. An existing experiment has been used to set limits on the electric dipole moment of the electron by probing the magnetization induced in a cryogenic gadolinium gallium garnet sample on application of a strong electric field. With suitable additions, including a movable source mass, this experiment can be used to explore “monopole-dipole” forces on polarized electrons with unique ormore » unprecedented sensitivity. As a result, the solid-state, nonmagnetic construction, combined with the low-noise conditions and extremely sensitive magnetometry available at cryogenic temperatures could lead to a sensitivity over 10 orders of magnitude greater than exiting limits in the range below 1 mm.« less

A direct method to transform between expansions in the configuration state function and Slater determinant bases

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

Olsen, Jeppe, E-mail: jeppe@chem.au.dk

2014-07-21

A novel algorithm is introduced for the transformation of wave functions between the bases of Slater determinants (SD) and configuration state functions (CSF) in the genealogical coupling scheme. By modifying the expansion coefficients as each electron is spin-coupled, rather than performing a single many-electron transformation, the large transformation matrix that plagues previous approaches is avoided and the required number of operations is drastically reduced. As an example of the efficiency of the algorithm, the transformation for a configuration with 30 unpaired electrons and singlet spin is discussed. For this case, the 10 × 10{sup 6} coefficients in the CSF basismore » is obtained from the 150 × 10{sup 6} coefficients in the SD basis in 1 min, which should be compared with the seven years that the previously employed method is estimated to require.« less

Characterizing Bonding Patterns in Diradicals and Triradicals by Density-Based Wave Function Analysis: A Uniform Approach.

PubMed

Orms, Natalie; Rehn, Dirk R; Dreuw, Andreas; Krylov, Anna I

2018-02-13

Density-based wave function analysis enables unambiguous comparisons of the electronic structure computed by different methods and removes ambiguity of orbital choices. We use this tool to investigate the performance of different spin-flip methods for several prototypical diradicals and triradicals. In contrast to previous calibration studies that focused on energy gaps between high- and low spin-states, we focus on the properties of the underlying wave functions, such as the number of effectively unpaired electrons. Comparison of different density functional and wave function theory results provides insight into the performance of the different methods when applied to strongly correlated systems such as polyradicals. We show that canonical molecular orbitals for species like large copper-containing diradicals fail to correctly represent the underlying electronic structure due to highly non-Koopmans character, while density-based analysis of the same wave function delivers a clear picture of the bonding pattern.

Periodic table of 3d-metal dimers and their ions.

PubMed

Gutsev, G L; Mochena, M D; Jena, P; Bauschlicher, C W; Partridge, H

2004-10-08

The ground states of the mixed 3d-metal dimers TiV, TiCr, TiMn, TiFe, TiCo, TiNi, TiCu, TiZn, VCr, VMn, VFe, VCo, VNi, VCu, VZn, CrMn, CrFe, CrCo, CrNi, CrCu, CrZn, MnFe, MnCo, MnNi, MnCu, MnZn, FeCo, FeNi, FeCu, FeZn, CoNi, CoCu, CoZn, NiCu, NiZn, and CuZn along with their singly negatively and positively charged ions are assigned based on the results of computations using density functional theory with generalized gradient approximation for the exchange-correlation functional. Except for TiCo and CrMn, our assignment agrees with experiment. Computed spectroscopic constants (r(e),omega(e),D(o)) are in fair agreement with experiment. The ground-state spin multiplicities of all the ions are found to differ from the spin multiplicities of the corresponding neutral parents by +/-1. Except for TiV, MnFe, and MnCu, the number of unpaired electrons, N, in a neutral ground-state dimer is either N(1)+N(2) or mid R:N(1)-N(2)mid R:, where N(1) and N(2) are the numbers of unpaired 3d electrons in the 3d(n)4s(1) occupation of the constituent atoms. Combining the present and previous results obtained at the same level of theory for homonuclear 3d-metal and ScX (X=Ti-Zn) dimers allows one to construct "periodic" tables of all 3d-metal dimers along with their singly charged ions.

Exploring Applications of Covalent Organic Frameworks: Homogeneous Reticulation of Radicals for Dynamic Nuclear Polarization.

PubMed

Cao, Wei; Wang, Wei David; Xu, Hai-Sen; Sergeyev, Ivan V; Struppe, Jochem; Wang, Xiaoling; Mentink-Vigier, Frederic; Gan, Zhehong; Xiao, Ming-Xing; Wang, Lu-Yao; Chen, Guo-Peng; Ding, San-Yuan; Bai, Shi; Wang, Wei

2018-06-06

Rapid progress has been witnessed in the past decade in the fields of covalent organic frameworks (COFs) and dynamic nuclear polarization (DNP). In this contribution, we bridge these two fields by constructing radical-embedded COFs as promising DNP agents. Via polarization transfer from unpaired electrons to nuclei, DNP realizes significant enhancement of NMR signal intensities. One of the crucial issues in DNP is to screen for suitable radicals to act as efficient polarizing agents, the basic criteria for which are homogeneous distribution and fixed orientation of unpaired electrons. We therefore envisioned that the crystalline and porous structures of COFs, if evenly embedded with radicals, may work as a new "crystalline sponge" for DNP experiments. As a proof of concept, we constructed a series of proxyl-radical-embedded COFs (denoted as PR( x)-COFs) and successfully applied them to achieve substantial DNP enhancement. Benefiting from the bottom-up and multivariate synthetic strategies, proxyl radicals have been covalently reticulated, homogeneously distributed, and rigidly embedded into the crystalline and mesoporous frameworks with adjustable concentration ( x%). Excellent performance of PR( x)-COFs has been observed for DNP 1 H, 13 C, and 15 N solid-state NMR enhancements. This contribution not only realizes the direct construction of radical COFs from radical monomers, but also explores the new application of COFs as DNP polarizing agents. Given that many radical COFs can therefore be rationally designed and facilely constructed with well-defined composition, distribution, and pore size, we expect that our effort will pave the way for utilizing radical COFs as standard polarizing agents in DNP NMR experiments.

Feasibility of reading LiF thermoluminescent dosimeters by electron spin resonance

NASA Astrophysics Data System (ADS)

Breen, S. L.; Battista, J. J.

1999-08-01

Lithium fluoride is a commonly used solid state dosimeter. During irradiation, electrons and holes become trapped in crystal imperfections; thermoluminescence dosimetry measures their thermally induced recombination. Electron paramagnetic resonance (EPR) spectroscopy can be used to measure the resonant absorption of microwaves by the unpaired electrons trapped in LiF. In an effort to extend the use of LiF dosimeters to smaller sizes and to the harsh environments encountered in internal dosimetry, EPR was evaluated as an alternative technique to read the radiation dose delivered to TLD-100 dosimeters. TLD-100 rods were irradiated with a 60Co source to doses of 10 Gy to 100 Gy. A radiation-induced signal (with a g-value of 2.002) could be detected only at liquid nitrogen temperatures at doses above 20 Gy. The EPR spectrum of irradiated LiF contains three components, one of which correlates positively with dose. However, the low sensitivity of the technique, and difficulty in interpreting the EPR spectrum from polycrystalline dosimeters, preclude its use as a dosimetry technique.

Feasibility of reading LiF thermoluminescent dosimeters by electron spin resonance.

PubMed

Breen, S L; Battista, J J

1999-08-01

Lithium fluoride is a commonly used solid state dosimeter. During irradiation, electrons and holes become trapped in crystal imperfections; thermoluminescence dosimetry measures their thermally induced recombination. Electron paramagnetic resonance (EPR) spectroscopy can be used to measure the resonant absorption of microwaves by the unpaired electrons trapped in LiF. In an effort to extend the use of LiF dosimeters to smaller sizes and to the harsh environments encountered in internal dosimetry, EPR was evaluated as an alternative technique to read the radiation dose delivered to TLD-100 dosimeters. TLD-100 rods were irradiated with a 60Co source to doses of 10 Gy to 100 Gy. A radiation-induced signal (with a g-value of 2.002) could be detected only at liquid nitrogen temperatures at doses above 20 Gy. The EPR spectrum of irradiated LiF contains three components, one of which correlates positively with dose. However, the low sensitivity of the technique, and difficulty in interpreting the EPR spectrum from polycrystalline dosimeters, preclude its use as a dosimetry technique.

Effect of calcination routes on phase formation of BaTiO3 and their electronic and magnetic properties

NASA Astrophysics Data System (ADS)

Majumder, Supriyo; Choudhary, R. J.; Tripathi, M.; Phase, D. M.

2018-05-01

We have investigated the phase formation and correlation between electronic and magnetic properties of oxygen deficient BaTiO3 ceramics, synthesized by solid state reaction method, following different calcination paths. The phase analysis divulge that a higher calcination temperature above 1000° C is favored for tetragonal phase formation than the cubic phase. The core level X-ray photo electron spectroscopy measurements confirm the presence of oxygen vacancies and oxygen vacancy mediated Ti3+ states. As the calcination temperature and calcination time increases these oxygen vacancies and hence Ti3+ concentrations reduce in the sample. The temperature dependent magnetization curves suggest unexpected magnetic ordering, which may be due to the presence of unpaired electron at the t2g state (d1) of nearest-neighbor Ti atoms. In magnetization vs magnetic field isotherms, the regular decrease of saturation moment value with increasing calcination temperature and calcination time, can be discussed considering the amount of oxygen deficiency induced Ti3+ concentrations, present in the sample.

Joint refinement model for the spin resolved one-electron reduced density matrix of YTiO3 using magnetic structure factors and magnetic Compton profiles data.

PubMed

Gueddida, Saber; Yan, Zeyin; Kibalin, Iurii; Voufack, Ariste Bolivard; Claiser, Nicolas; Souhassou, Mohamed; Lecomte, Claude; Gillon, Béatrice; Gillet, Jean-Michel

2018-04-28

In this paper, we propose a simple cluster model with limited basis sets to reproduce the unpaired electron distributions in a YTiO 3 ferromagnetic crystal. The spin-resolved one-electron-reduced density matrix is reconstructed simultaneously from theoretical magnetic structure factors and directional magnetic Compton profiles using our joint refinement algorithm. This algorithm is guided by the rescaling of basis functions and the adjustment of the spin population matrix. The resulting spin electron density in both position and momentum spaces from the joint refinement model is in agreement with theoretical and experimental results. Benefits brought from magnetic Compton profiles to the entire spin density matrix are illustrated. We studied the magnetic properties of the YTiO 3 crystal along the Ti-O 1 -Ti bonding. We found that the basis functions are mostly rescaled by means of magnetic Compton profiles, while the molecular occupation numbers are mainly modified by the magnetic structure factors.

Giant titanium electron wave function in gallium oxide: A potential electron-nuclear spin system for quantum information processing

NASA Astrophysics Data System (ADS)

Mentink-Vigier, Frédéric; Binet, Laurent; Vignoles, Gerard; Gourier, Didier; Vezin, Hervé

2010-11-01

The hyperfine interactions of the unpaired electron with eight surrounding G69a and G71a nuclei in Ti-doped β-Ga2O3 were analyzed by electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopies. They are dominated by strong isotropic hyperfine couplings due to a direct Fermi contact interaction with Ga nuclei in octahedral sites of rutile-type chains oriented along b axis, revealing a large anisotropic spatial extension of the electron wave function. Titanium in β-Ga2O3 is thus best described as a diffuse (Ti4+-e-) pair rather than as a localized Ti3+ . Both electron and G69a nuclear spin Rabi oscillations could be observed by pulsed EPR and pulsed ENDOR, respectively. The electron spin decoherence time is about 1μs (at 4 K) and an upper bound of 520μs (at 8 K) is estimated for the nuclear decoherence time. Thus, β-Ga2O3:Ti appears to be a potential spin-bus system for quantum information processing with a large nuclear spin quantum register.

Vibrational spectroscopy and density functional theory analysis of 3-O-caffeoylquinic acid

NASA Astrophysics Data System (ADS)

Mishra, Soni; Tandon, Poonam; Eravuchira, Pinkie J.; El-Abassy, Rasha M.; Materny, Arnulf

2013-03-01

Density functional theory (DFT) calculations are being performed to investigate the geometric, vibrational, and electronic properties of the chlorogenic acid isomer 3-CQA (1R,3R,4S,5R)-3-{[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-1,4,5-trihydroxycyclohexanecarboxylic acid), a major phenolic compound in coffee. DFT calculations with the 6-311G(d,p) basis set produce very good results. The electrostatic potential mapped onto an isodensity surface has been obtained. A natural bond orbital analysis (NBO) has been performed in order to study intramolecular bonding, interactions among bonds, and delocalization of unpaired electrons. HOMO-LUMO studies give insights into the interaction of the molecule with other species. The calculated HOMO and LUMO energies indicate that a charge transfer occurs within the molecule.

Exploring Redox States, Doping and Ordering of Electroactive Star-Shaped Oligo(aniline)s.

PubMed

Mills, Benjamin M; Fey, Natalie; Marszalek, Tomasz; Pisula, Wojciech; Rannou, Patrice; Faul, Charl F J

2016-11-14

We have prepared a simple star-shaped oligo(aniline) (TDPB) and characterised it in detail by MALDI-TOF MS, UV/Vis/NIR spectroscopy, time-dependent DFT, cyclic voltammetry and EPR spectroscopy. TDPB is part of an underdeveloped class of π-conjugated molecules with great potential for organic electronics, display and sensor applications. It is redox active and reacts with acids to form radical cations. Acid-doped TDPB shows behaviour similar to discotic liquid crystals, with X-ray scattering investigations revealing columnar self-assembled arrays. The combination of unpaired electrons and supramolecular stacking suggests that star-shaped oligo(aniline)s like TDPB have the potential to form conducting nanowires and organic magnetic materials. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Coordination Chemistry of Linear Oligopyrrolic Fragments Inspired by Heme Metabolites

NASA Astrophysics Data System (ADS)

Gautam, Ritika

Linear oligopyrroles are degradation products of heme, which is converted in the presence of heme oxygenase to bile pigments, such as biliverdin and bilirubin. These tetrapyrrolic oligopyrroles are ubiquitously present in biological systems and find applications in the fields of catalysis and sensing. These linear tetrapyrrolic scaffolds are further degraded into linear tripyrrolic and dipyrrolic fragments. Although these lower oligopyrroles are abundantly present, their coordination chemistry requires further characterization. This dissertation focuses mainly on two classes of bioinspired linear oligopyrroles, propentdyopent and tripyrrindione, and their transition metal complexes, which present a rich ligand-based redox chemistry. Chapter 1 offers an overview of heme degradation to different classes of linear oligopyrroles and properties of their transition metal complexes. Chapter 2 is focused on the tripyrrin-1,14-dione scaffold of the urinary pigment uroerythrin, which coordinates divalent transition metals palladium and copper with square planar geometry. Specifically, the tripyrrin-1, 14-dione ligand binds Cu(II) and Pd(II) as a dianionic organic radical under ambient conditions. The electrochemical study confirms the presence of ligand based redox chemistry, and one electron oxidation or reduction reactions do not alter the planar geometry around the metal center. The X-Ray analysis and the electron paramagnetic resonance (EPR) studies of the complexes in the solid and solution phase reveals intermolecular interactions between the ligand based unpaired electrons and therefore formation of neutral pi-pi dimers. In Chapter 3, the antioxidant activity and the fluorescence sensor properties of the tripyrrin-1,14-dione ligand in the presence of superoxide are described. We found that the tripyrrindione ligand undergoes one-electron reduction in the presence of the superoxide radical anion (O2•- ) to form highly fluorescent H3TD1•- radical anion, which emits at 635 nm. This reaction also explains the antioxidant properties of the linear tripyrrin-1,14-dione ligand, which acts as a scavenger of O2•-. In Chapter 4, the zinc binding properties of the tripyrrin-1,14-dione ligand are described. The tripyrrolic ligand coordinates as a dianionic ligand with the divalent Zn(II) ion in both organic and aqueous buffered conditions. The complex formed is highly fluorescent with a long wavelength emission band at 648 nm. The X-Ray crystallography analysis indicates the existence of dinuclear complex [Zn(TD1•)(H2O)]2, featuring a distorted square planar geometry around the Zn(II) center. In Chapter 5, the coordination chemistry of the dipyrrin-1,9-dione fragment of propentdyopent ligand is shown with a series of transition metals like (e.g., Co(II), Ni(II), Cu(II) and Zn(II)), which form homoleptic tetrahedral complexes. The spectroscopic and electrochemical characterization confirms that the complexes shows ligand-based redox chemistry and acts as reservoirs for unpaired electrons. Chapter 6 describes the formation of the fluorescent BODIPY complex of propentdyopent ligand. The dipyrrin-1,9-dione scaffold of heme metabolite propendyopent undergoes a one-pot reaction with borontrifluoride etherate in toluene to form a green fluorescent [(pdp)BF2] complex. Spectroscopic studies reveal that the meso-unsubstituted [(pdp)BF2] complex is stable in tetrahydrofuran and has a quantum yield of 0.13. Electrochemical studies confirm that the complex undergoes ligand-based reduction and acts as a host for an unpaired electron.

Interstrand disulfide crosslinking of DNA bases supports a double nucleotide unpairing mechanism for flap endonucleases.

PubMed

Beddows, Amanda; Patel, Nikesh; Finger, L David; Atack, John M; Williams, David M; Grasby, Jane A

2012-09-14

Flap endonucleases (FENs) are proposed to select their target phosphate diester by unpairing the two terminal nucleotides of duplex. Interstrand disulfide crosslinks, introduced by oxidation of thiouracil and thioguanine bases, abolished the specificity of human FEN1 for hydrolysis one nucleotide into the 5'-duplex.

Hydration sites of unpaired RNA bases: a statistical analysis of the PDB structures.

PubMed

Kirillova, Svetlana; Carugo, Oliviero

2011-10-19

Hydration is crucial for RNA structure and function. X-ray crystallography is the most commonly used method to determine RNA structures and hydration and, therefore, statistical surveys are based on crystallographic results, the number of which is quickly increasing. A statistical analysis of the water molecule distribution in high-resolution X-ray structures of unpaired RNA nucleotides showed that: different bases have the same penchant to be surrounded by water molecules; clusters of water molecules indicate possible hydration sites, which, in some cases, match those of the major and minor grooves of RNA and DNA double helices; complex hydrogen bond networks characterize the solvation of the nucleotides, resulting in a significant rigidity of the base and its surrounding water molecules. Interestingly, the hydration sites around unpaired RNA bases do not match, in general, the positions that are occupied by the second nucleotide when the base-pair is formed. The hydration sites around unpaired RNA bases were found. They do not replicate the atom positions of complementary bases in the Watson-Crick pairs.

Hydration sites of unpaired RNA bases: a statistical analysis of the PDB structures

PubMed Central

2011-01-01

Background Hydration is crucial for RNA structure and function. X-ray crystallography is the most commonly used method to determine RNA structures and hydration and, therefore, statistical surveys are based on crystallographic results, the number of which is quickly increasing. Results A statistical analysis of the water molecule distribution in high-resolution X-ray structures of unpaired RNA nucleotides showed that: different bases have the same penchant to be surrounded by water molecules; clusters of water molecules indicate possible hydration sites, which, in some cases, match those of the major and minor grooves of RNA and DNA double helices; complex hydrogen bond networks characterize the solvation of the nucleotides, resulting in a significant rigidity of the base and its surrounding water molecules. Interestingly, the hydration sites around unpaired RNA bases do not match, in general, the positions that are occupied by the second nucleotide when the base-pair is formed. Conclusions The hydration sites around unpaired RNA bases were found. They do not replicate the atom positions of complementary bases in the Watson-Crick pairs. PMID:22011380

An RNA Recognition Motif-Containing Protein Functions in Meiotic Silencing by Unpaired DNA

PubMed Central

Samarajeewa, Dilini A.; Manitchotpisit, Pennapa; Henderson, Miranda; Xiao, Hua; Rehard, David G.; Edwards, Kevin A.; Shiu, Patrick K. T.; Hammond, Thomas M.

2017-01-01

Meiotic silencing by unpaired DNA (MSUD) is a biological process that searches pairs of homologous chromosomes (homologs) for segments of DNA that are unpaired. Genes found within unpaired segments are silenced for the duration of meiosis. In this report, we describe the identification and characterization of Neurospora crassa sad-7, a gene that encodes a protein with an RNA recognition motif (RRM). Orthologs of sad-7 are found in a wide range of ascomycete fungi. In N. crassa, sad-7 is required for a fully efficient MSUD response to unpaired genes. Additionally, at least one parent must have a functional sad-7 allele for a cross to produce ascospores. Although sad-7-null crosses are barren, sad-7Δ strains grow at a wild-type (wt) rate and appear normal under vegetative growth conditions. With respect to expression, sad-7 is transcribed at baseline levels in early vegetative cultures, at slightly higher levels in mating-competent cultures, and is at its highest level during mating. These findings suggest that SAD-7 is specific to mating-competent and sexual cultures. Although the role of SAD-7 in MSUD remains elusive, green fluorescent protein (GFP)-based tagging studies place SAD-7 within nuclei, perinuclear regions, and cytoplasmic foci of meiotic cells. This localization pattern is unique among known MSUD proteins and raises the possibility that SAD-7 coordinates nuclear, perinuclear, and cytoplasmic aspects of MSUD. PMID:28667016

Behavioral studies of learning in the Africanized honey bee (Apis mellifera L.).

PubMed

Abramson, Charles I; Aquino, Italo S

2002-01-01

Experiments on basic classical conditioning phenomena in adult and young Africanized honey bees (Apis mellifera L.) are described. Phenomena include conditioning to various stimuli, extinction (both unpaired and CS only), conditioned inhibition, color and odor discrimination. In addition to work on basic phenomena, experiments on practical applications of conditioning methodology are illustrated with studies demonstrating the effects of insecticides on learning and the reaction of bees to consumer products. Electron microscope photos are presented of Africanized workers, drones, and queen bees. Possible sub-species differences between Africanized and European bees are discussed. Copyright 2002 S. Karger AG, Basel

Mechanism of the electrochemical oligomerization of thionaphteneindole: a spectroscopic study

NASA Astrophysics Data System (ADS)

Poggi, Gabriella; Casalbore Miceli, Giuseppe; Beggiato, Giancarlo; Emmi, Salvatore S.

1997-10-01

The UV, visible and NIR spectra recorded during electrolysis of TNI in CH 2Cl 2 have been studied as a function of electrolysis time and of the quantity of charge exchanged. Among the oligomeric species that might be responsible for the behaviour observed, particular attention has been devoted to dimers of TNI characterized by different charges, presence of unpaired electrons, and deprotonation of the amino hydrogens. A sample of these species has been described theoretically by means of the PM3 semiempirical hamiltonian and their spectra have been computed giving results in reasonable agreement with the observed transitions.

Multifrequency Pulsed EPR Studies of Biologically Relevant Manganese(II) Complexes

PubMed Central

Stich, T. A.; Lahiri, S.; Yeagle, G.; Dicus, M.; Brynda, M.; Gunn, A.; Aznar, C.; DeRose, V. J.; Britt, R. D.

2011-01-01

Electron paramagnetic resonance studies at multiple frequencies (MF EPR) can provide detailed electronic structure descriptions of unpaired electrons in organic radicals, inorganic complexes, and metalloenzymes. Analysis of these properties aids in the assignment of the chemical environment surrounding the paramagnet and provides mechanistic insight into the chemical reactions in which these systems take part. Herein, we present results from pulsed EPR studies performed at three different frequencies (9, 31, and 130 GHz) on [Mn(II)(H2O)6]2+, Mn(II) adducts with the nucleotides ATP and GMP, and the Mn(II)-bound form of the hammerhead ribozyme (MnHH). Through line shape analysis and interpretation of the zero-field splitting values derived from successful simulations of the corresponding continuous-wave and field-swept echo-detected spectra, these data are used to exemplify the ability of the MF EPR approach in distinguishing the nature of the first ligand sphere. A survey of recent results from pulsed EPR, as well as pulsed electron-nuclear double resonance and electron spin echo envelope modulation spectroscopic studies applied to Mn(II)-dependent systems, is also presented. PMID:22190766

Redox-Active Bis(phenolate) N-Heterocyclic Carbene [OCO] Pincer Ligands Support Cobalt Electron Transfer Series Spanning Four Oxidation States.

PubMed

Harris, Caleb F; Bayless, Michael B; van Leest, Nicolaas P; Bruch, Quinton J; Livesay, Brooke N; Bacsa, John; Hardcastle, Kenneth I; Shores, Matthew P; de Bruin, Bas; Soper, Jake D

2017-10-16

A new family of low-coordinate Co complexes supported by three redox-noninnocent tridentate [OCO] pincer-type bis(phenolate) N-heterocyclic carbene (NHC) ligands are described. Combined experimental and computational data suggest that the charge-neutral four-coordinate complexes are best formulated as Co(II) centers bound to closed-shell [OCO] 2- dianions, of the general formula [(OCO)Co II L] (where L is a solvent-derived MeCN or THF). Cyclic voltammograms of the [(OCO)Co II L] complexes reveal three oxidations accessible at potentials below 1.2 V vs Fc + /Fc, corresponding to generation of formally Co(V) species, but the true physical/spectroscopic oxidation states are much lower. Chemical oxidations afford the mono- and dications of the imidazoline NHC-derived complex, which were examined by computational and magnetic and spectroscopic methods, including single-crystal X-ray diffraction. The metal and ligand oxidation states of the monocationic complex are ambiguous; data are consistent with formulation as either [( S OCO)Co III (THF) 2 ] + containing a closed-shell [ S OCO] 2- diphenolate ligand bound to a S = 1 Co(III) center, or [( S OCO • )Co II (THF) 2 ] + with a low-spin Co(II) ion ferromagnetically coupled to monoanionic [ S OCO • ] - containing a single unpaired electron distributed across the [OCO] framework. The dication is best described as [( S OCO 0 )Co II (THF) 3 ] 2+ , with a single unpaired electron localized on the d 7 Co(II) center and a doubly oxidized, charge-neutral, closed-shell S OCO 0 ligand. The combined data provide for the first time unequivocal and structural evidence for [OCO] ligand redox activity. Notably, varying the degree of unsaturation in the NHC backbone shifts the ligand-based oxidation potentials by up to 400 mV. The possible chemical origins of this unexpected shift, along with the potential utility of the [OCO] pincer ligands for base-metal-mediated organometallic coupling catalysis, are discussed.

Imaging of Endogenous Metabolites of Plant Leaves by Mass Spectrometry Based on Laser Activated Electron Tunneling.

PubMed

Huang, Lulu; Tang, Xuemei; Zhang, Wenyang; Jiang, Ruowei; Chen, Disong; Zhang, Juan; Zhong, Hongying

2016-04-07

A new mass spectrometric imaging approach based on laser activated electron tunneling (LAET) was described and applied to analysis of endogenous metabolites of plant leaves. LAET is an electron-directed soft ionization technique. Compressed thin films of semiconductor nanoparticles of bismuth cobalt zinc oxide were placed on the sample plate for proof-of-principle demonstration because they can not only absorb ultraviolet laser but also have high electron mobility. Upon laser irradiation, electrons are excited from valence bands to conduction bands. With appropriate kinetic energies, photoexcited electrons can tunnel away from the barrier and eventually be captured by charge deficient atoms present in neutral molecules. Resultant unpaired electron subsequently initiates specific chemical bond cleavage and generates ions that can be detected in negative ion mode of the mass spectrometer. LAET avoids the co-crystallization process of routinely used organic matrix materials with analyzes in MALDI (matrix assisted-laser desorption ionization) analysis. Thus uneven distribution of crystals with different sizes and shapes as well as background peaks in the low mass range resulting from matrix molecules is eliminated. Advantages of LAET imaging technique include not only improved spatial resolution but also photoelectron capture dissociation which produces predictable fragment ions.

An ICU Preanesthesia Evaluation Form Reduces Missing Preoperative Key Information.

PubMed

Chuy, Katherine; Yan, Zhe; Fleisher, Lee; Liu, Renyu

2012-09-28

A comprehensive preoperative evaluation is critical for providing anesthetic care for patients from the intensive care unit (ICU). There has been no preoperative evaluation form specific for ICU patients that allows for a rapid and focused evaluation by anesthesia providers, including junior residents. In this study, a specific preoperative form was designed for ICU patients and evaluated to allow residents to perform the most relevant and important preoperative evaluations efficiently. The following steps were utilized for developing the preoperative evaluation form: 1) designed a new preoperative form specific for ICU patients; 2) had the form reviewed by attending physicians and residents, followed by multiple revisions; 3) conducted test releases and revisions; 4) released the final version and conducted a survey; 5) compared data collection from new ICU form with that from a previously used generic form. Each piece of information on the forms was assigned a score, and the score for the total missing information was determined. The score for each form was presented as mean ± standard deviation (SD), and compared by unpaired t test. A P value < 0.05 was considered statistically significant. Of 52 anesthesiologists (19 attending physicians, 33 residents) responding to the survey, 90% preferred the final new form; and 56% thought the new form would reduce perioperative risk for ICU patients. Forty percent were unsure whether the form would reduce perioperative risk. Over a three month period, we randomly collected 32 generic forms and 25 new forms. The average score for missing data was 23 ± 10 for the generic form and 8 ± 4 for the new form (P = 2.58E-11). A preoperative evaluation form designed specifically for ICU patients is well accepted by anesthesia providers and helped to reduce missing key preoperative information. Such an approach is important for perioperative patient safety.

Mobile technology in radiology resident education.

PubMed

Korbage, Aiham C; Bedi, Harprit S

2012-06-01

The authors hypothesized that ownership of a mobile electronic device would result in more time spent learning radiology. Current trends in radiology residents' studying habits, their use of electronic and printed radiology learning resources, and how much of the funds allotted to them are being used toward printed vs electronic education tools were assessed in this study. A survey study was conducted among radiology residents across the United States from June 13 to July 5, 2011. Program directors listed in the Association of Program Directors in Radiology e-mail list server received an e-mail asking for residents to participate in an online survey. The questionnaire consisted of 12 questions and assessed the type of institution, the levels of training of the respondents, and book funds allocated to residents. It also assessed the residents' study habits, access to portable devices, and use of printed and electronic radiology resources. Radiology residents are adopters of new technologies, with 74% owning smart phones and 37% owning tablet devices. Respondents spend nearly an equal amount of time learning radiology from printed textbooks as they do from electronic resources. Eighty-one percent of respondents believe that they would spend more time learning radiology if provided with tablet devices. There is considerable use of online and electronic resources and mobile devices among the current generation of radiology residents. Benefits, such as more study time, may be obtained by radiology programs that incorporate tablet devices into the education of their residents. Copyright © 2012 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Bonding quandary in the [Cu3S2]3+ core: insights from the analysis of domain averaged fermi holes and the local spin.

PubMed

Ponec, Robert; Ramos-Cordoba, Eloy; Salvador, Pedro

2013-03-07

The electronic structure of the trinuclear symmetric complex [(tmedaCu)3S2 ](3+), whose Cu3S2 core represents a model of the active site of metalloenzymes involved in biological processes, has been in recent years the subject of vigorous debate. The complex exists as an open-shell triplet, and discussions concerned the question whether there is a direct S-S bond in the [Cu3S2](3+) core, whose answer is closely related to the problem of the formal oxidation state of Cu atoms. In order to contribute to the elucidation of the serious differences in the conclusions of earlier studies, we report in this study the detailed comprehensive analysis of the electronic structure of the [Cu3S2](3+) core using the methodologies that are specifically designed to address three particular aspects of the bonding in the core of the above complex, namely, the presence and/or absence of direct S-S bond, the existence and the nature of spin-spin interactions among the atoms in the core, and the formal oxidation state of Cu atoms in the core. Using such a combined approach, it was possible to conclude that the picture of bonding consistently indicates the existence of a weak direct two-center-three-electron (2c-3e) S-S bond, but at the same time, the observed lack of any significant local spin in the core of the complex is at odds with the suggested existence of antiferromagnetic coupling among the Cu and S atoms, so that the peculiarities of the bonding in the complex seem to be due to extensive delocalization of the unpaired spin in the [Cu3S2](3+) core. Finally, a scrutiny of the effective atomic hybrids and their occupations points to a predominant formal Cu(II) oxidation state, with a weak contribution of partial Cu(I) character induced mainly by the partial flow of electrons from S to Cu atoms and high delocalization of the unpaired spin in the [Cu3S2](3+) core.

High-temperature heat capacity of Co3O4 spinel: thermally induced spin unpairing transition

USGS Publications Warehouse

Mocala, K.; Navrotsky, A.; Sherman, David M.

1992-01-01

A strong anomaly was found in the heat capacity of Co3O4 between 1000 K and the decomposition temperature. This anomaly is not related to the decomposition of Co3O4 to CoO. The measured entropy of transition, ??S=46??4 J mol-1 K-1 of Co3O4, supports the interpretation that this anomaly reflects a spin unpairing transition in octahedrally coordinated Co3+ cations. Experimental values of heat capacity, heat content and entropy of Co3O4 in the high temperature region are provided. The enthalpy of the spin unpairing transition is 53??4 kJ mol-1 of Co3O4. ?? 1992 Springer-Verlag.

Stable Organic Radicals as Hole Injection Dopants for Efficient Optoelectronics.

PubMed

Bin, Zhengyang; Guo, Haoqing; Liu, Ziyang; Li, Feng; Duan, Lian

2018-02-07

Precursors of reactive organic radicals have been widely used as n-dopants in electron-transporting materials to improve electron conductivity and enhance electron injection. However, the utilization of organic radicals in hole counterparts has been ignored. In this work, stable organic radicals have been proved for the first time to be efficient dopants to enhance hole injection. From the absorbance spectra and the ultraviolet photoelectron spectra, we could observe an efficient electron transfer between the organic radical, (4-N-carbazolyl-2,6-dichlorophenyl)bis(2,4,6-trichlorophenyl)methyl (TTM-1Cz), and the widely used hole injection material, 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN). When the unpaired electron of TTM-1Cz is transferred to HAT-CN, it would be oxidized to a TTM-1Cz cation with a newly formed lowest unoccupied molecular orbital which is quite close to the highest occupied molecular orbital (HOMO) of the hole-transporting material (HTM). In this way, the TTM-1Cz cation would promote the electron extraction from the HOMO of the HTM and improve hole injection. Using TTM-1Cz-doped HAT-CN as the hole injection layer, efficient organic light-emitting diodes with extremely low voltages can be attained.

A magnetic resonance study of MoS(2) fullerene-like nanoparticles.

PubMed

Panich, A M; Shames, A I; Rosentsveig, R; Tenne, R

2009-09-30

We report on the first nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) investigation of inorganic fullerene-like MoS(2) nanoparticles. Spectra of bulk 2H-MoS(2) samples have also been measured for comparison. The similarity between the measured quadrupole coupling constants and chemical shielding anisotropy parameters for bulk and fullerene-like MoS(2) reflects the nearly identical local crystalline environments of the Mo atoms in these two materials. EPR measurements show that fullerene-like MoS(2) exhibits a larger density of dangling bonds carrying unpaired electrons, indicative of them having a more defective structure than the bulk sample. The latter observation explains the increase in the spin-lattice relaxation rate observed in the NMR measurements for this sample in comparison with the bulk 2H- MoS(2) ones.

A magnetic resonance study of MoS2 fullerene-like nanoparticles

NASA Astrophysics Data System (ADS)

Panich, A. M.; Shames, A. I.; Rosentsveig, R.; Tenne, R.

2009-09-01

We report on the first nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) investigation of inorganic fullerene-like MoS2 nanoparticles. Spectra of bulk 2H-MoS2 samples have also been measured for comparison. The similarity between the measured quadrupole coupling constants and chemical shielding anisotropy parameters for bulk and fullerene-like MoS2 reflects the nearly identical local crystalline environments of the Mo atoms in these two materials. EPR measurements show that fullerene-like MoS2 exhibits a larger density of dangling bonds carrying unpaired electrons, indicative of them having a more defective structure than the bulk sample. The latter observation explains the increase in the spin-lattice relaxation rate observed in the NMR measurements for this sample in comparison with the bulk 2H- MoS2 ones.

Spin localization, magnetic ordering, and electronic properties of strongly correlated Ln2O3 sesquioxides (Ln=La, Ce, Pr, Nd)

NASA Astrophysics Data System (ADS)

El-Kelany, Kh. E.; Ravoux, C.; Desmarais, J. K.; Cortona, P.; Pan, Y.; Tse, J. S.; Erba, A.

2018-06-01

Lanthanide sesquioxides are strongly correlated materials characterized by highly localized unpaired electrons in the f band. Theoretical descriptions based on standard density functional theory (DFT) formulations are known to be unable to correctly describe their peculiar electronic and magnetic features. In this study, electronic and magnetic properties of the first four lanthanide sesquioxides in the series are characterized through a reliable description of spin localization as ensured by hybrid functionals of the DFT, which include a fraction of nonlocal Fock exchange. Because of the high localization of the f electrons, multiple metastable electronic configurations are possible for their ground state depending on the specific partial occupation of the f orbitals: the most stable configuration is here found and characterized for all systems. Magnetic ordering is explicitly investigated, and the higher stability of an antiferromagnetic configuration with respect to the ferromagnetic one is predicted. The critical role of the fraction of exchange on the description of their electronic properties (notably, on spin localization and on the electronic band gap) is addressed. In particular, a recently proposed theoretical approach based on a self-consistent definition—through the material dielectric response—of the optimal fraction of exchange in hybrid functionals is applied to these strongly correlated materials.

Characterizing bonding patterns in diradicals and triradicals by density-based wave function analysis: A uniform approach

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

Orms, Natalie; Rehn, Dirk; Dreuw, Andreas

Density-based wave function analysis enables unambiguous comparisons of electronic structure computed by different methods and removes ambiguity of orbital choices. Here, we use this tool to investigate the performance of different spin-flip methods for several prototypical diradicals and triradicals. In contrast to previous calibration studies that focused on energy gaps between high and low spin-states, we focus on the properties of the underlying wave functions, such as the number of effectively unpaired electrons. Comparison of different density functional and wave function theory results provides insight into the performance of the different methods when applied to strongly correlated systems such asmore » polyradicals. We also show that canonical molecular orbitals for species like large copper-containing diradicals fail to correctly represent the underlying electronic structure due to highly non-Koopmans character, while density-based analysis of the same wave function delivers a clear picture of bonding pattern.« less

An ab initio investigation of possible intermediates in the reaction of the hydroxyl and hydroperoxyl radicals

NASA Technical Reports Server (NTRS)

Jackels, C. F.

1985-01-01

Ab initio quantum chemical techniques are used to investigate covalently-bonded and hydrogen-bonded species that may be important intermediates in the reaction of hydroxyl and hydroperoxyl radicals. Stable structures of both types are identified. Basis sets of polarized double zeta quality and large scale configuration interaction wave functions are utilized. Based on electronic energies, the covalently bonded HOOOH species is 26.4 kcal/mol more stable than the OH and HO2 radicals. Similarly, the hydrogen bonded HO---HO2 species has an electronic energy 4.7 kcal/mol below that of the component radicals, after correction is made for the basis set superposition error. The hydrogen bonded form is planar, possesses one relatively normal hydrogen bond, and has the lowest energy 3A' and 1A' states that are essentially degenerate. The 1A" and 3A" excited states produced by rotation of the unpaired OH electron into the molecular plane are very slightly bound.

Characterizing bonding patterns in diradicals and triradicals by density-based wave function analysis: A uniform approach

DOE PAGES

Orms, Natalie; Rehn, Dirk; Dreuw, Andreas; ...

2017-12-21

Density-based wave function analysis enables unambiguous comparisons of electronic structure computed by different methods and removes ambiguity of orbital choices. Here, we use this tool to investigate the performance of different spin-flip methods for several prototypical diradicals and triradicals. In contrast to previous calibration studies that focused on energy gaps between high and low spin-states, we focus on the properties of the underlying wave functions, such as the number of effectively unpaired electrons. Comparison of different density functional and wave function theory results provides insight into the performance of the different methods when applied to strongly correlated systems such asmore » polyradicals. We also show that canonical molecular orbitals for species like large copper-containing diradicals fail to correctly represent the underlying electronic structure due to highly non-Koopmans character, while density-based analysis of the same wave function delivers a clear picture of bonding pattern.« less

Disorder and defects are not intrinsic to boron carbide

NASA Astrophysics Data System (ADS)

Mondal, Swastik; Bykova, Elena; Dey, Somnath; Ali, Sk Imran; Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Parakhonskiy, Gleb; van Smaalen, Sander

2016-01-01

A unique combination of useful properties in boron-carbide, such as extreme hardness, excellent fracture toughness, a low density, a high melting point, thermoelectricity, semi-conducting behavior, catalytic activity and a remarkably good chemical stability, makes it an ideal material for a wide range of technological applications. Explaining these properties in terms of chemical bonding has remained a major challenge in boron chemistry. Here we report the synthesis of fully ordered, stoichiometric boron-carbide B13C2 by high-pressure-high-temperature techniques. Our experimental electron-density study using high-resolution single-crystal synchrotron X-ray diffraction data conclusively demonstrates that disorder and defects are not intrinsic to boron carbide, contrary to what was hitherto supposed. A detailed analysis of the electron density distribution reveals charge transfer between structural units in B13C2 and a new type of electron-deficient bond with formally unpaired electrons on the C-B-C group in B13C2. Unprecedented bonding features contribute to the fundamental chemistry and materials science of boron compounds that is of great interest for understanding structure-property relationships and development of novel functional materials.

Calculations of Electron Transport through Radicals

NASA Astrophysics Data System (ADS)

Smeu, Manuel; Dilabio, Gino

2010-03-01

Organic radicals are of interest in molecular electronics because a singly occupied molecular orbital (SOMO) would have a higher energy than its doubly occupied analog, suggesting they might make better conductors. The unpaired electron present in a radical leads to degeneracy splitting in other energy levels and such molecules may act as spin filters. Our study employs first principles transport calculations that are performed using a combination of density functional theory and a non-equilibrium Green's function technique. The conductance of 1,4-benzenediamine (BDA) molecules bridging two Au electrodes was modeled. These molecules were substituted in the 2-position with: -CH3, -NH2, and -OH; as well as with their radical analogs: -CH2, -NH, and -O, all of which have π-type SOMOs. The conductance of a radical with a σ-type SOMO was also calculated from a BDA molecule with the H atom in the 2-position removed. Comparing the transmission spectra for these species will yield insight into the nature of electron transport through radicals vs. transport through their reduced form as well as the nature of transport through π- and σ-type molecular orbitals.

Thermodynamic and electron paramagnetic resonance characterization of flavin in succinate dehydrogenase.

PubMed

Ohnishi, T; King, T E; Salerno, J C; Blum, H; Bowyer, J R; Maida, T

1981-06-10

Thermodynamic parameters of succinate dehydrogenase flavin were determined potentiometrically from the analysis of free radical signal levels as a function of the oxidation-reduction potential. Midpoint redox potentials of consecutive 1-electron transfer steps are -127 and -31 mV at pH 7.0. This corresponds to a stability constant of intermediate stability, 2.5 x 10(-2), which suggests flavin itself may be a converter from n = 2 to n = 1 electron transfer steps. The pK values of the free radical (FlH . in equilibrium Fl . -) and the fully reduced form (FlH2 in equilibrium FlH-) were estimated as 8.0 +/- 0.2 and 7.7 +/- 0.2, respectively. Succinate dehydrogenase flavosemiquinone elicits an EPR spectrum at g = 2.00 with a peak to peak width of 1.2 mT even in the protonated form, suggesting the delocalization in the unpaired electron density. A close proximity of succinate dehydrogenase flavin and iron-sulfur cluster S-1 was demonstrated based on the enhancement of flavin spin relaxation by Center S-1.

Electron Spin Polarization Transfer to ortho-H2 by Interaction of para-H2 with Paramagnetic Species: A Key to a Novel para → ortho Conversion Mechanism.

PubMed

Terenzi, Camilla; Bouguet-Bonnet, Sabine; Canet, Daniel

2015-05-07

We report that at ambient temperature and with 100% enriched para-hydrogen (p-H2) dissolved in organic solvents, paramagnetic spin catalysis of para → ortho hydrogen conversion is accompanied at the onset by a negative ortho-hydrogen (o-H2) proton NMR signal. This novel finding indicates an electron spin polarization transfer, and we show here that this can only occur if the H2 molecule is dissociated upon its transient adsorption by the paramagnetic catalyst. Following desorption, o-H2 is created until the thermodynamic equilibrium is reached. A simple theory confirms that in the presence of a static magnetic field, the hyperfine coupling between unpaired electrons and nuclear spins is responsible for the observed polarization transfer. Owing to the negative electron gyromagnetic ratio, this explains the experimental results and ascertains an as yet unexplored mechanism for para → ortho conversion. Finally, we show that the recovery of o-H2 magnetization toward equilibrium can be simply modeled, leading to the para → ortho conversion rate.

The effect of the 16-hour intern workday restriction on surgical residents' in-hospital activities.

PubMed

Dennis, Bradley M; Long, Eric L; Zamperini, Katherine M; Nakayama, Don K

2013-01-01

To observe the effects of the 2011 Accreditation Council on Graduate Medical Education 16-hour intern workday restrictions on surgical residents' clinical and educational activities. All the residents recorded the following weekly in-hospital activities during February and March 2011 (year before intern work restrictions) and 2012 (first year under new requirements): operating room (OR) and clinic; bedside procedures; rounds and ward work; on-call duties in hospital; communication (e.g., checkouts and family and patient discussions); education (conferences and study); and personal (rest and meals). Descriptive statistics were calculated in 3 resident groups (interns, first postgraduate year [PGY1]; junior, PGY2 and 3; and senior, PGY4 and 5). The unpaired t test was used to compare data between 2011 and 2012; significance was set at p< 0.05. Medical school affiliated hospital. Categorical resident trainees in surgery, PGY1-5, 4 residents per level, with all 20 residents participating in the study. From 2011 to 2012, time spent in the hospital by the intern did not change (all results in h/wk, mean±standard deviation: 68.5±13.8 to 72.8±15.8, respectively) but the time devoted to specific activities changed significantly. In-hospital personal time decreased by 50% (5.3±4.6 to 2.6±2.0, p = 0.004). Interns spent less time placing central lines (2.1±2.2 to 0.9±1.2, p = 0.006) and more on rounds (8.8±8.8 to 14.2±9.8, p = 0.027), which included supervision with upper level residents. There was no change in the total time spent in the OR, the clinic, performing bedside procedures, and educational activities. Changes in intern work did not affect the time junior and senior residents spent on bedside procedures, time spent in the clinic, and total time spent in the hospital. In 2012, junior residents spent less time in educational activities (11.4±8.5 to 7.0±4.5, p = 0.0007) and the seniors spent more time in the OR (13.7±7.5 to 20.6±10.7, p = 0.0002). The 16-hour restriction preserved interns' educational activities and time spent in the OR and clinic, but changed resident work activities at all levels. The time spent on rounds increased, time spent by the juniors on conferences decreased, and time spent by senior residents in the OR increased. Duty restrictions in general and intern supervision requirements demand ongoing adjustments in resident work schedules. Copyright © 2013 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

On the identity of the last known stable radical in X-irradiated sucrose

NASA Astrophysics Data System (ADS)

Kusakovskij, Jevgenij; De Cooman, Hendrik; Sagstuen, Einar; Callens, Freddy; Vrielinck, Henk

2017-04-01

Identification of radiation-induced radicals in relatively simple molecules is a prerequisite for the understanding of reaction pathways of the radiation chemistry of complex systems. Sucrose presents an additional practical interest as a versatile radiation dosimetric system. In this work, we present a periodic density functional theory study aimed to identify the fourth stable radical species in this carbohydrate. The proposed model is a fragment suspended in the lattice by hydrogen bonds with an unpaired electron at the original C5' carbon of the fructose unit. It requires a double scission of the ring accompanied by substantial chemical and geometric reorganization.

Experimental evidence of Ga-vacancy induced room temperature ferromagnetic behavior in GaN films

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

Roul, Basanta; Kumar, Mahesh; Central Research Laboratory, Bharat Electronics, Bangalore 560013

We have grown Ga deficient GaN epitaxial films on (0001) sapphire substrate by plasma-assisted molecular beam epitaxy and report the experimental evidence of room temperature ferromagnetic behavior. The observed yellow emission peak in room temperature photoluminescence spectra and the peak positioning at 300 cm{sup -1} in Raman spectra confirms the existence of Ga vacancies. The x-ray photoelectron spectroscopic measurements further confirmed the formation of Ga vacancies; since the N/Ga is found to be >1. The ferromagnetism is believed to originate from the polarization of the unpaired 2p electrons of N surrounding the Ga vacancy.

Silacyanogen

NASA Astrophysics Data System (ADS)

Ignatyev, Igor S.; Schaefer, Henry F., III

1997-10-01

Structures of all possible linear isomers of the Si-substituted cyanogen were optimized at the SCF, B3LYP, MP2, and CCSD levels of theory. At all levels of theory the most stable isomer was found to be SiNCN, while for cyanogen the most stable structure is well known to be NCCN. The theoretical ordering of the stability of the acyclic structures is SiNCN>SiNNO>NSiCN>NSiNC. The difference in the order of stability of silacyanogen and cyanogen isomers is rationalized, taking into account the position of the unpaired electron on carbon in the CN radical and that on nitrogen in the SiN radical.

Defect types and room-temperature ferromagnetism in undoped rutile TiO2 single crystals

NASA Astrophysics Data System (ADS)

Li, Dong-Xiang; Qin, Xiu-Bo; Zheng, Li-Rong; Li, Yu-Xiao; Cao, Xing-Zhong; Li, Zhuo-Xin; Yang, Jing; Wang, Bao-Yi

2013-03-01

Room-temperature ferromagnetism has been experimentally observed in annealed rutile TiO2 single crystals when a magnetic field is applied parallel to the sample plane. By combining X-ray absorption near the edge structure spectrum and positron annihilation lifetime spectroscopy, Ti3+—VO defect complexes (or clusters) have been identified in annealed crystals at a high vacuum. We elucidate that the unpaired 3d electrons in Ti3+ ions provide the observed room-temperature ferromagnetism. In addition, excess oxygen ions in the TiO2 lattice could induce a number of Ti vacancies which obviously increase magnetic moments.

Studies on the effects of gamma radiation on 6-aminopenicillanic acid and its derivatives by the EPR method

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

Dziegielewski, J.; Jezowska-Trzebiatowska, B.; Kozlowski, H.

Commercial samples of 6-aminopenicillanic acid (6-APA), potassium benzyl- penicillin; procaine benzyl-penicillin, procaine hydrochlorides and sodium 3-(o- chlorophenyl)-5-methyl-4-isoxasol penicillin salt were irradiated with 0.5 to 40 Mrad and examined by the EPR method within the temperature range 100 to 300 deg K. No influence of the irradiation dose on powder EPR spectra structure has been stated, except for benzyl-penicillin procaine. In irradiated samples of antibiotics the presence of radicals with unpaired electrons on sulfur atoms and carbon atoms abuttmg on the thioether group has been stated. (auth)

Ultraviolet laser spectroscopy of jet-cooled CaNC and SrNC free radicals: Observation of bent excited electronic states

NASA Astrophysics Data System (ADS)

Greetham, Gregory M.; Ellis, Andrew M.

2000-11-01

New electronic transitions of the CaNC and SrNC free radicals have been identified in the near ultraviolet. For CaNC one new system, labeled the D˜-X˜ transition, was observed in the 31 500-33 400 cm-1 region. Two new transitions were found for SrNC, the D˜-X˜ and Ẽ-X˜ systems spanning 29 100-31 000 and 32 750-34 000 cm-1, respectively. Jet-cooled laser excitation spectra yield complex vibrational structure, much of which is attributed to excitation of the bending vibration. This has been used to infer that the molecule adopts a nonlinear equilibrium geometry in the upper electronic state in all three band systems, in contrast to the linear ground electronic state. This structural change is accounted for by the increased diffuseness of the unpaired electron in the excited states, which favors deviation from linearity. All three new excited states are assigned 2A' symmetry and correlate with 2Σ+ states in the linear molecule limit. Tentative estimates for the barriers to linearity in the D˜ 2A' states of CaNC and SrNC have been determined as ˜700 and ˜1050 cm-1, respectively.

Probing Fe-V Bonding in a C3-Symmetric Heterobimetallic Complex.

PubMed

Greer, Samuel M; McKay, Johannes; Gramigna, Kathryn M; Thomas, Christine M; Stoian, Sebastian A; Hill, Stephen

2018-04-30

Direct metal-metal bonding of two distinct first-row transition metals remains relatively unexplored compared to their second- and third-row heterobimetallic counterparts. Herein, a recently reported Fe-V triply bonded species, [V( i PrNPPh 2 ) 3 FeI] (1; Kuppuswamy, S.; Powers, T. M.; Krogman, J. P.; Bezpalko, M. W.; Foxman, B. M.; Thomas, C. M. Vanadium-iron complexes featuring metal-metal multiple bonds. Chem. Sci. 2013, 4, 3557-3565), is investigated using high-frequency electron paramagnetic resonance, field- and temperature-dependent 57 Fe nuclear gamma resonance (Mössbauer) spectroscopy, and high-field electron-electron double resonance detected nuclear magnetic resonance. From the use of this suite of physical methods, we have assessed the electronic structure of 1. These studies allow us to establish the effective g̃ tensors as well as the Fe/V electro-nuclear hyperfine interaction tensors of the spin S = 1 / 2 ground state. We have rationalized these tensors in the context of ligand field theory supported by quantum chemical calculations. This theoretical analysis suggests that the S = 1 / 2 ground state originates from a single unpaired electron predominately localized on the Fe site.

Electronic and structural properties of vacancies and hydrogen adsorbates on trilayer graphene

NASA Astrophysics Data System (ADS)

Menezes, Marcos G.; Capaz, Rodrigo B.

2015-08-01

Using ab initio calculations, we study the electronic and structural properties of vacancies and hydrogen adsorbates on trilayer graphene. Those defects are found to share similar low-energy electronic features, since they both remove a pz electron from the honeycomb lattice and induce a defect level near the Fermi energy. However, a vacancy also leaves unpaired σ electrons on the lattice, which lead to important structural differences and also contribute to magnetism. We explore both ABA and ABC stackings and compare properties such as formation energies, magnetic moments, spin density and the local density of states (LDOS) of the defect levels. These properties show a strong sensitivity to the layer in which the defect is placed and smaller sensitivities to sublattice placing and stacking type. Finally, for the ABC trilayer, we also study how these states behave in the presence of an external field, which opens a tunable gap in the band structure of the non-defective system. The pz defect states show a strong hybridization with band states as the field increases, with reduction and eventually loss of magnetization, and a non-magnetic, midgap-like state is found when the defect is at the middle layer.

Electronic and Structural Properties of Vacancies and Hydrogen Adsorbates on Trilayer Graphene

NASA Astrophysics Data System (ADS)

Menezes, Marcos; Capaz, Rodrigo

2015-03-01

Using ab initio calculations, we study the electronic and structural properties of vacancies and hydrogen adsorbates on trilayer graphene. Those defects are found to share similar low-energy electronic features, since they both remove a pz electron from the honeycomb lattice and induce a defect level near the Fermi energy. However, a vacancy also leaves unpaired σ electrons on the lattice, which lead to important structural differences and also contribute to magnetism. We explore both ABA and ABC stackings and compare properties such as formation energies, magnetic moments, spin density and the local density of states (LDOS) of the defect levels. These properties show a strong sensitivity to the layer in which the defect is placed and smaller sensitivities to sublattice placing and stacking type. Finally, for the ABC trilayer, we also study how these states behave in the presence of an external electrical field, which opens a tunable gap in the band structure of the non-defective system. The pz defect states show a strong hybridization with band states as the field increases, with reduction and eventually loss of magnetization, and a non-magnetic, midgap-like state is found when the defect is at the middle layer.

The first radical-based spintronic memristors: Towards resistive RAMs made of organic magnets

NASA Astrophysics Data System (ADS)

Goss, Karin; Krist, Florian; Seyfferle, Simon; Hoefel, Udo; Paretzki, Alexa; Dressel, Martin; Bogani, Lapo; Institut Fuer Anorganische Chemie, University of Stuttgart Collaboration; 1. Physikalisches Institut, University of Stuttgart Team

2014-03-01

Using molecules as building blocks for electronic devices offers ample possibilities for new device functionalities due to a chemical tunability much higher than that of standard inorganic materials, and at the same time offers a decrease in the size of the electronic component down to the single-molecule level. Purely organic molecules containing no metallic centers such as organic radicals can serve as an electronic component with magnetic properties due to the unpaired electron in the radical state. Here we present memristive logic units based on organic radicals of the nitronyl-nitroxide kind. Integrating these purely molecular units as a spin coated layer into crossbar arrays, electrically induced unipolar resistive switching is observed with a change in resistance of up to 100%. We introduce a model based on filamentary reorganization of molecules of different oxidation state revealing the importance of the molecular nature for the switching properties. The major role of the oxidation state of these paramagnetic molecules introduces a magnetic field dependence to the device functionality, which goes along with magnetoresistive charactistics observed for the material. These are the first steps towards a spintronic implementation of organic radicals in electronic devices.

Photoacoustic measurement of differential broadening of the Lambda doublets in NO(X 2Pi 1/2,v = 2-0) by Ar

NASA Technical Reports Server (NTRS)

Pine, A. S.

1989-01-01

A differential broadening of the Lambda doublets in the v = 2-0 overtone band of the 2pi1/2 ground electronic state of NO in an Ar buffer gas has been observed by photoacoustic spectroscopy using a tunable color-center laser. The broadening coefficients for the f symmetry components are larger than for the e symmetry components by up to about 6 percent for J of about 16.5. This differential depends on J and vanishes at low J, implicating the anisotropy of the unpaired electron Pi orbital in the plane of rotation. The 2Pi3/2 transitions are slightly broader than the 2Pi1/2 as a result of spin-flipping collisional relaxation. The observed line shapes also exhibit collisional or Dicke narrowing due to velocity-changing collisions.

Zero-field splitting in the isoelectronic aqueous Gd(III) and Eu(II) complexes from a first principles analysis

NASA Astrophysics Data System (ADS)

Khan, S.; Peters, V.; Kowalewski, J.; Odelius, M.

2018-03-01

The zero-field splitting (ZFS) of the ground state octet in aqueous Eu(II) and Gd(III) solutions was investigated through multi- configurational quantum chemical calculations and ab initio molecular dynamics (AIMD) simulations. Investigation of the ZFS of the lanthanide ions is essential to understand the electron spin dynamics and nuclear spin relaxation around paramagnetic ions and consequently the mechanisms underlying applications like magnetic resonance imaging. We found by comparing clusters at identical geometries but different metallic centres that there is not a simple relationship for their ZFS, in spite of the complexes being isoelectronic - each containing 7 unpaired f electrons. Through sampling it was established that inclusion of the first hydration shell has a dominant (over 90 %) influence on the ZFS. Extended sampling of aqueous Gd(III) showed that the 2 nd order spin Hamiltonian formalism is valid and that the rhombic ZFS component is decisive.

Core filling and snaking instability of dark solitons in spin-imbalanced superfluid Fermi gases

NASA Astrophysics Data System (ADS)

Reichl, Matthew D.; Mueller, Erich J.

2017-05-01

We use the time-dependent Bogoliubov-de Gennes equations to study dark solitons in three-dimensional spin-imbalanced superfluid Fermi gases. We explore how the shape and dynamics of dark solitons are altered by the presence of excess unpaired spins which fill their low-density core. The unpaired particles broaden the solitons and suppress the transverse snake instability. We discuss ways of observing these phenomena in cold-atom experiments.

Functional formation of domain V of the poliovirus noncoding region: significance of unpaired bases.

PubMed

Rowe, A; Burlison, J; Macadam, A J; Minor, P D

2001-10-10

Previously we have shown that polioviruses with mutations that disrupt the predicted secondary structure of the 5' noncoding region of domain V are temperature sensitive for growth. Non-temperature-sensitive revertant viruses had mutations that re-formed secondary structure by a direct back mutation of changes in the opposite strand. We mutated unpaired regions and selected revertants of viruses with single base deletions, where no obvious back mutation was available in order to gain information on secondary structure. Results indicated that conservation of length of a three base loop between two double-stranded stems was essential for a functional domain V to form. The requirement for the unpaired "hinge" base at 484 which is implicated in the attenuation of Sabin 2 was also confirmed. Results also underline the necessity for functional folding over local secondary structure stability. Copyright 2001 Academic Press.

Quantitative analysis of dislocation arrangements induced by electromigration in a passivated Al (0.5 wt % Cu) interconnect

NASA Astrophysics Data System (ADS)

Barabash, R. I.; Ice, G. E.; Tamura, N.; Valek, B. C.; Bravman, J. C.; Spolenak, R.; Patel, J. R.

2003-05-01

Electromigration during accelerated testing can induce plastic deformation in apparently undamaged Al interconnect lines as recently revealed by white beam scanning x-ray microdiffraction. In the present article, we provide a first quantitative analysis of the dislocation structure generated in individual micron-sized Al grains during an in situ electromigration experiment. Laue reflections from individual interconnect grains show pronounced streaking during the early stages of electromigration. We demonstrate that the evolution of the dislocation structure during electromigration is highly inhomogeneous and results in the formation of unpaired randomly distributed dislocations as well as geometrically necessary dislocation boundaries. Approximately half of all unpaired dislocations are grouped within the walls. The misorientation created by each boundary and density of unpaired individual dislocations is determined. The origin of the observed plastic deformation is considered in view of the constraints for dislocation arrangements under the applied electric field during electromigration.

Investigation of defects in In–Ga–Zn oxide thin film using electron spin resonance signals

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

Nonaka, Yusuke; Kurosawa, Yoichi; Komatsu, Yoshihiro

In–Ga–Zn oxide (IGZO) is a next-generation semiconductor material seen as an alternative to silicon. Despite the importance of the controllability of characteristics and the reliability of devices, defects in IGZO have not been fully understood. We investigated defects in IGZO thin films using electron spin resonance (ESR) spectroscopy. In as-sputtered IGZO thin films, we observed an ESR signal which had a g-value of g = 2.010, and the signal was found to disappear under thermal treatment. Annealing in a reductive atmosphere, such as N{sub 2} atmosphere, generated an ESR signal with g = 1.932 in IGZO thin films. The temperature dependence of the lattermore » signal suggests that the signal is induced by delocalized unpaired electrons (i.e., conduction electrons). In fact, a comparison between the conductivity and ESR signal intensity revealed that the signal's intensity is related to the number of conduction electrons in the IGZO thin film. The signal's intensity did not increase with oxygen vacancy alone but also with increases in both oxygen vacancy and hydrogen concentration. In addition, first-principle calculation suggests that the conduction electrons in IGZO may be generated by defects that occur when hydrogen atoms are inserted into oxygen vacancies.« less

Photo-catalytic Activities of Plant Hormones on Semiconductor Nanoparticles by Laser-Activated Electron Tunneling and Emitting

PubMed Central

Tang, Xuemei; Huang, Lulu; Zhang, Wenyang; Jiang, Ruowei; Zhong, Hongying

2015-01-01

Understanding of the dynamic process of laser-induced ultrafast electron tunneling is still very limited. It has been thought that the photo-catalytic reaction of adsorbents on the surface is either dependent on the number of resultant electron-hole pairs where excess energy is lost to the lattice through coupling with phonon modes, or dependent on irradiation photon wavelength. We used UV (355 nm) laser pulses to excite electrons from the valence band to the conduction band of titanium dioxide (TiO2), zinc oxide (ZnO) and bismuth cobalt zinc oxide (Bi2O3)0.07(CoO)0.03(ZnO)0.9 semiconductor nanoparticles with different photo catalytic properties. Photoelectrons are extracted, accelerated in a static electric field and eventually captured by charge deficient atoms of adsorbed organic molecules. A time-of-flight mass spectrometer was used to detect negative molecules and fragment ions generated by un-paired electron directed bond cleavages. We show that the probability of electron tunneling is determined by the strength of the static electric field and intrinsic electron mobility of semiconductors. Photo-catalytic dissociation or polymerization reactions of adsorbents are highly dependent on the kinetic energy of tunneling electrons as well as the strength of laser influx. By using this approach, photo-activities of phytohormones have been investigated. PMID:25749635

Photo-catalytic Activities of Plant Hormones on Semiconductor Nanoparticles by Laser-Activated Electron Tunneling and Emitting

NASA Astrophysics Data System (ADS)

Tang, Xuemei; Huang, Lulu; Zhang, Wenyang; Jiang, Ruowei; Zhong, Hongying

2015-03-01

Understanding of the dynamic process of laser-induced ultrafast electron tunneling is still very limited. It has been thought that the photo-catalytic reaction of adsorbents on the surface is either dependent on the number of resultant electron-hole pairs where excess energy is lost to the lattice through coupling with phonon modes, or dependent on irradiation photon wavelength. We used UV (355 nm) laser pulses to excite electrons from the valence band to the conduction band of titanium dioxide (TiO2), zinc oxide (ZnO) and bismuth cobalt zinc oxide (Bi2O3)0.07(CoO)0.03(ZnO)0.9 semiconductor nanoparticles with different photo catalytic properties. Photoelectrons are extracted, accelerated in a static electric field and eventually captured by charge deficient atoms of adsorbed organic molecules. A time-of-flight mass spectrometer was used to detect negative molecules and fragment ions generated by un-paired electron directed bond cleavages. We show that the probability of electron tunneling is determined by the strength of the static electric field and intrinsic electron mobility of semiconductors. Photo-catalytic dissociation or polymerization reactions of adsorbents are highly dependent on the kinetic energy of tunneling electrons as well as the strength of laser influx. By using this approach, photo-activities of phytohormones have been investigated.

Effect of the metal environment on the ferromagnetic interaction in the Co-NC-W pairs of octacyanotungstate(V)-Cobalt(II) three-dimensional networks.

PubMed

Clima, Sergiu; Hendrickx, Marc F A; Chibotaru, Liviu F; Soncini, Alessandro; Mironov, Vladimir; Ceulemans, Arnout

2007-04-02

State of the art CASSCF and CASPT2 calculations have been performed to elucidate the nature of ferromagnetism of CoII-NC-WV pairs in the three-dimensional compound [[WV(CN)2]2[(micro-CN)4CoII(H2O)2]3.4H2O]n, which has been recently synthesized and investigated by a number of experimental techniques (Herrera, J. M.; Bleuzen, A.; Dromzée, Y.; Julve, M.; Lloret, F.; Verdaguer, M. Inorg. Chem. 2003, 42, 7052-7059). In this network, the Co ions are in the high-spin (S = 3/2) state, while the single unpaired electron on the W centers occupies the lowest orbital of the dz2 type of the 5d shell. In agreement with the suggestion made by Herrera et al., we find that the ferromagnetism is due to a certain occupation scheme of the orbitals from the parent octahedral t2g shell on CoII sites, in which the orbital accommodating the unpaired electron is orthogonal to the dz2 orbitals of the surrounding W ions. We investigate the stabilization of such an orbital configuration on the Co sites and find that it cannot be achieved in the ground state of isolated mononuclear fragments [CoII(NC)4(OH2)2]2- for any conformations of the coordinated water molecules and Co-N-C bond angles. On the other hand, it is stabilized by the interaction of the complex with neighboring W ions, which are simulated here by effective potentials. The calculated exchange coupling constants for the CoII-NC-WV binuclear fragments are in reasonable agreement with the measured Curie-Weiss constant for this compound. As additional evidence for the inferred electronic configuration on the Co sites, the ligand-field transitions, the temperature-dependent magnetic susceptibility, and the field-dependent low-temperature magnetization, simulated ab initio for the mononuclear Co fragments, are in agreement with the available data for another compound [WIV[(micro-CN)4-CoII(H2O)2]2.4H2O]n containing diamagnetic W and high-spin Co ions in an isostructural environment.

Unadjusted Bivariate Two-Group Comparisons: When Simpler is Better.

PubMed

Vetter, Thomas R; Mascha, Edward J

2018-01-01

Hypothesis testing involves posing both a null hypothesis and an alternative hypothesis. This basic statistical tutorial discusses the appropriate use, including their so-called assumptions, of the common unadjusted bivariate tests for hypothesis testing and thus comparing study sample data for a difference or association. The appropriate choice of a statistical test is predicated on the type of data being analyzed and compared. The unpaired or independent samples t test is used to test the null hypothesis that the 2 population means are equal, thereby accepting the alternative hypothesis that the 2 population means are not equal. The unpaired t test is intended for comparing dependent continuous (interval or ratio) data from 2 study groups. A common mistake is to apply several unpaired t tests when comparing data from 3 or more study groups. In this situation, an analysis of variance with post hoc (posttest) intragroup comparisons should instead be applied. Another common mistake is to apply a series of unpaired t tests when comparing sequentially collected data from 2 study groups. In this situation, a repeated-measures analysis of variance, with tests for group-by-time interaction, and post hoc comparisons, as appropriate, should instead be applied in analyzing data from sequential collection points. The paired t test is used to assess the difference in the means of 2 study groups when the sample observations have been obtained in pairs, often before and after an intervention in each study subject. The Pearson chi-square test is widely used to test the null hypothesis that 2 unpaired categorical variables, each with 2 or more nominal levels (values), are independent of each other. When the null hypothesis is rejected, 1 concludes that there is a probable association between the 2 unpaired categorical variables. When comparing 2 groups on an ordinal or nonnormally distributed continuous outcome variable, the 2-sample t test is usually not appropriate. The Wilcoxon-Mann-Whitney test is instead preferred. When making paired comparisons on data that are ordinal, or continuous but nonnormally distributed, the Wilcoxon signed-rank test can be used. In analyzing their data, researchers should consider the continued merits of these simple yet equally valid unadjusted bivariate statistical tests. However, the appropriate use of an unadjusted bivariate test still requires a solid understanding of its utility, assumptions (requirements), and limitations. This understanding will mitigate the risk of misleading findings, interpretations, and conclusions.

Intrinsic Nucleic Acid Dynamics Modulates HIV-1 Nucleocapsid Protein Binding to Its Targets

PubMed Central

Bazzi, Ali; Zargarian, Loussiné; Chaminade, Françoise; De Rocquigny, Hugues; René, Brigitte; Mély, Yves; Fossé, Philippe; Mauffret, Olivier

2012-01-01

HIV-1 nucleocapsid protein (NC) is involved in the rearrangement of nucleic acids occurring in key steps of reverse transcription. The protein, through its two zinc fingers, interacts preferentially with unpaired guanines in single-stranded sequences. In mini-cTAR stem-loop, which corresponds to the top half of the cDNA copy of the transactivation response element of the HIV-1 genome, NC was found to exhibit a clear preference for the TGG sequence at the bottom of mini-cTAR stem. To further understand how this site was selected among several potential binding sites containing unpaired guanines, we probed the intrinsic dynamics of mini-cTAR using 13C relaxation measurements. Results of spin relaxation time measurements have been analyzed using the model-free formalism and completed by dispersion relaxation measurements. Our data indicate that the preferentially recognized guanine in the lower part of the stem is exempt of conformational exchange and highly mobile. In contrast, the unrecognized unpaired guanines of mini-cTAR are involved in conformational exchange, probably related to transient base-pairs. These findings support the notion that NC preferentially recognizes unpaired guanines exhibiting a high degree of mobility. The ability of NC to discriminate between close sequences through their dynamic properties contributes to understanding how NC recognizes specific sites within the HIV genome. PMID:22745685

Defect types and room temperature ferromagnetism in N-doped rutile TiO2 single crystals

NASA Astrophysics Data System (ADS)

Qin, Xiu-Bo; Li, Dong-Xiang; Li, Rui-Qin; Zhang, Peng; Li, Yu-Xiao; Wang, Bao-Yi

2014-06-01

The magnetic properties and defect types of virgin and N-doped TiO2 single crystals are probed by superconducting quantum interference device (SQUID), X-ray photoelectron spectroscopy (XPS), and positron annihilation analysis (PAS). Upon N doping, a twofold enhancement of the saturation magnetization is observed. Apparently, this enhancement is not related to an increase in oxygen vacancy, rather to unpaired 3d electrons in Ti3+, arising from titanium vacancies and the replacement of O with N atoms in the rutile structure. The production of titanium vacancies can enhance the room temperature ferromagnetism (RTFM), and substitution of O with N is the onset of ferromagnetism by inducing relatively strong ferromagnetic ordering.

Room-temperature ferromagnetism observed in C-/N-/O-implanted MgO single crystals

NASA Astrophysics Data System (ADS)

Li, Qiang; Ye, Bonian; Hao, Yingping; Liu, Jiandang; Zhang, Jie; Zhang, Lijuan; Kong, Wei; Weng, Huimin; Ye, Bangjiao

2013-01-01

MgO single crystals were implanted with 70 keV C/N/O ions at room temperature with respective doses of 2 × 1016 and 2 × 1017 ions/cm2. All samples with high-dose implantation showed room temperature hysteresis in magnetization loops. Magnetization and slow positron annihilation measurements confirmed that room temperature ferromagnetism in O-implanted samples was attributed to the presence of Mg vacancies. Furthermore, the introduction of C or N played more effective role in ferromagnetic performance than Mg vacancies. Moreover, the magnetic moment possibly occurred from the localized wave function of unpaired electrons and the exchange interaction formed a long-range magnetic order.

A dynamic nuclear polarization strategy for multi-dimensional Earth's field NMR spectroscopy.

PubMed

Halse, Meghan E; Callaghan, Paul T

2008-12-01

Dynamic nuclear polarization (DNP) is introduced as a powerful tool for polarization enhancement in multi-dimensional Earth's field NMR spectroscopy. Maximum polarization enhancements, relative to thermal equilibrium in the Earth's magnetic field, are calculated theoretically and compared to the more traditional prepolarization approach for NMR sensitivity enhancement at ultra-low fields. Signal enhancement factors on the order of 3000 are demonstrated experimentally using DNP with a nitroxide free radical, TEMPO, which contains an unpaired electron which is strongly coupled to a neighboring (14)N nucleus via the hyperfine interaction. A high-quality 2D (19)F-(1)H COSY spectrum acquired in the Earth's magnetic field with DNP enhancement is presented and compared to simulation.

Spin-imbalanced pairing and Fermi surface deformation in flat bands

NASA Astrophysics Data System (ADS)

Huhtinen, Kukka-Emilia; Tylutki, Marek; Kumar, Pramod; Vanhala, Tuomas I.; Peotta, Sebastiano; Törmä, Päivi

2018-06-01

We study the attractive Hubbard model with spin imbalance on two lattices featuring a flat band: the Lieb and kagome lattices. We present mean-field phase diagrams featuring exotic superfluid phases, similar to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, whose stability is confirmed by dynamical mean-field theory. The nature of the pairing is found to be richer than just the Fermi surface shift responsible for the usual FFLO state. The presence of a flat band allows for changes in the particle momentum distributions at null energy cost. This facilitates formation of nontrivial superfluid phases via multiband Cooper pair formation: the momentum distribution of the spin component in the flat band deforms to mimic the Fermi surface of the other spin component residing in a dispersive band. The Fermi surface of the unpaired particles that are typical for gapless superfluids becomes deformed as well. The results highlight the profound effect of flat dispersions on Fermi surface instabilities, and provide a potential route for observing spin-imbalanced superfluidity and superconductivity.

Alkali (Li, K and Na) and alkali-earth (Be, Ca and Mg) adatoms on SiC single layer

NASA Astrophysics Data System (ADS)

Baierle, Rogério J.; Rupp, Caroline J.; Anversa, Jonas

2018-03-01

First-principles calculations within the density functional theory (DFT) have been addressed to study the energetic stability, and electronic properties of alkali and alkali-earth atoms adsorbed on a silicon carbide (SiC) single layer. We observe that all atoms are most stable (higher binding energy) on the top of a Si atom, which moves out of the plane (in the opposite direction to the adsorbed atom). Alkali atoms adsorbed give raise to two spin unpaired electronic levels inside the band gap leading the SiC single layer to exhibit n-type semiconductor properties. For alkaline atoms adsorbed there is a deep occupied spin paired electronic level inside the band gap. These finding suggest that the adsorption of alkaline and alkali-earth atoms on SiC layer is a powerful feature to functionalize two dimensional SiC structures, which can be used to produce new electronic, magnetic and optical devices as well for hydrogen and oxygen evolution reaction (HER and OER, respectively). Furthermore, we observe that the adsorption of H2 is ruled by dispersive forces (van der Waals interactions) while the O2 molecule is strongly adsorbed on the functionalized system.

Seniority and orbital symmetry as tools for establishing a full configuration interaction hierarchy.

PubMed

Bytautas, Laimutis; Henderson, Thomas M; Jiménez-Hoyos, Carlos A; Ellis, Jason K; Scuseria, Gustavo E

2011-07-28

We explore the concept of seniority number (defined as the number of unpaired electrons in a determinant) when applied to the problem of electron correlation in atomic and molecular systems. Although seniority is a good quantum number only for certain model Hamiltonians (such as the pairing Hamiltonian), we show that it provides a useful partitioning of the electronic full configuration interaction (FCI) wave function into rapidly convergent Hilbert subspaces whose weight diminishes as its seniority number increases. The primary focus of this study is the adequate description of static correlation effects. The examples considered are the ground states of the helium, beryllium, and neon atoms, the symmetric dissociation of the N(2) and CO(2) molecules, as well as the symmetric dissociation of an H(8) hydrogen chain. It is found that the symmetry constraints that are normally placed on the spatial orbitals greatly affect the convergence rate of the FCI expansion. The energy relevance of the seniority zero sector (determinants with all paired electrons) increases dramatically if orbitals of broken spatial symmetry (as those commonly used for Hubbard Hamiltonian studies) are allowed in the wave function construction. © 2011 American Institute of Physics

Modulation of electronic and magnetic properties in InSe nanoribbons: edge effect

NASA Astrophysics Data System (ADS)

Wu, Meng; Shi, Jun-jie; Zhang, Min; Ding, Yi-min; Wang, Hui; Cen, Yu-lang; Guo, Wen-hui; Pan, Shu-hang; Zhu, Yao-hui

2018-05-01

Quite recently, the two-dimensional (2D) InSe nanosheet has become a hot material with great promise for advanced functional nano-devices. In this work, for the first time, we perform first-principles calculations on the structural, electronic, magnetic and transport properties of 1D InSe nanoribbons with/without hydrogen or halogen saturation. We find that armchair ribbons, with various edges and distortions, are all nonmagnetic semiconductors, with a direct bandgap of 1.3 (1.4) eV for bare (H-saturated) ribbons, and have the same high electron mobility of about 103 cm2V‑1s‑1 as the 2D InSe nanosheet. Zigzag InSe nanoribbons exhibit metallic behavior and diverse intrinsic ferromagnetic properties, with the magnetic moment of 0.5–0.7 μ B per unit cell, especially for their single-edge spin polarization. The edge spin orientation, mainly dominated by the unpaired electrons of the edge atoms, depends sensitively on the edge chirality. Hydrogen or halogen saturation can effectively recover the structural distortion, and modulate the electronic and magnetic properties. The binding energy calculations show that the stability of InSe nanoribbons is analogous to that of graphene and better than in 2D InSe nanosheets. These InSe nanoribbons, with novel electronic and magnetic properties, are thus very promising for use in electronic, spintronic and magnetoresistive nano-devices.

Modulation of electronic and magnetic properties in InSe nanoribbons: edge effect.

PubMed

Wu, Meng; Shi, Jun-Jie; Zhang, Min; Ding, Yi-Min; Wang, Hui; Cen, Yu-Lang; Guo, Wen-Hui; Pan, Shu-Hang; Zhu, Yao-Hui

2018-05-18

Quite recently, the two-dimensional (2D) InSe nanosheet has become a hot material with great promise for advanced functional nano-devices. In this work, for the first time, we perform first-principles calculations on the structural, electronic, magnetic and transport properties of 1D InSe nanoribbons with/without hydrogen or halogen saturation. We find that armchair ribbons, with various edges and distortions, are all nonmagnetic semiconductors, with a direct bandgap of 1.3 (1.4) eV for bare (H-saturated) ribbons, and have the same high electron mobility of about 10 3 cm 2 V -1 s -1 as the 2D InSe nanosheet. Zigzag InSe nanoribbons exhibit metallic behavior and diverse intrinsic ferromagnetic properties, with the magnetic moment of 0.5-0.7 μ B per unit cell, especially for their single-edge spin polarization. The edge spin orientation, mainly dominated by the unpaired electrons of the edge atoms, depends sensitively on the edge chirality. Hydrogen or halogen saturation can effectively recover the structural distortion, and modulate the electronic and magnetic properties. The binding energy calculations show that the stability of InSe nanoribbons is analogous to that of graphene and better than in 2D InSe nanosheets. These InSe nanoribbons, with novel electronic and magnetic properties, are thus very promising for use in electronic, spintronic and magnetoresistive nano-devices.

Electron spin resonance spectral analysis of irradiated royal jelly.

PubMed

Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

2014-01-15

The analysis of unpaired electron components in royal jelly was carried out using electron spin resonance (ESR) with the aim to develop a detection method for irradiated royal jelly. The ESR spectrum of royal jelly had natural signals derived from transition metals, including Fe(3+) and Cu(2+), and a signal line near g=2.00. After irradiation, a new splitting asymmetric spectrum with overall spectrum width ca. 10mT at g=2.004 was observed. The intensities of the signals at g=2.004 increased in proportion to the absorbed dose in samples under different storage conditions: fresh frozen royal jelly and dried royal jelly powder at room temperature. The signal intensity of the fresh frozen sample was stable after irradiation. One year after 10kGy irradiation of dried powder, the signal intensity was sevenfold greater than before irradiation, although the intensity continued to steadily decrease with time. This stable radiation-induced radical component was derived from the poorly soluble constituent of royal jelly. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synergistic effects of Lewis bases and substituents on the electronic structure and reactivity of boryl radicals.

PubMed

Lu, Dongmei; Wu, Chao; Li, Pengfei

2014-02-03

Boryl radicals have the potential for the development of new molecular entities and for application in new radical reactions. However, the effects of the substituents and coordinating Lewis bases on the reactivity of boryl radicals are not fully understood. By using first-principles methods, we investigated the spin-density distribution and reactivity of a series of boryl radicals with various substituents and Lewis bases. The substituents, along with the Lewis bases, only affect the radical reactivity when an unpaired electron is in the boron pz orbital, that is, for three-coordinate radicals. We found evidence of synergistic effects between the substituents and the Lewis bases that can substantially broaden the tunability of the reactivity of the boryl radicals. Among Lewis bases, pyridine and imidazol-2-ylidene show a similar capacity for stabilization by delocalizing the spin density. Electron-donating substituents, such as nitrogen, more efficiently stabilize boryl radicals than oxygen and carbon atoms. The reactivity of a boryl radical is always boron based, irrespective of the spin density on boron. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The shortest Th-Th distance from a new type of quadruple bond.

PubMed

Hu, Han-Shi; Kaltsoyannis, Nikolas

2017-02-15

Compounds featuring unsupported metal-metal bonds between actinide elements remain highly sought after yet confined experimentally to inert gas matrix studies. Notwithstanding this paucity, actinide-actinide bonding has been the subject of extensive computational research. In this contribution, high level quantum chemical calculations at both the scalar and spin-orbit levels are used to probe the Th-Th bonding in a range of zero valent systems of general formula LThThL. Several of these compounds have very short Th-Th bonds arising from a new type of Th-Th quadruple bond with a previously unreported electronic configuration featuring two unpaired electrons in 6d-based δ bonding orbitals. H 3 AsThThAsH 3 is found to have the shortest Th-Th bond yet reported (2.590 Å). The Th 2 unit is a highly sensitive probe of ligand electron donor/acceptor ability; we can tune the Th-Th bond from quadruple to triple, double and single by judicious choice of the L group, up to 2.888 Å for singly-bonded ONThThNO.

CH/sub 3/xxx/sup 13/CO/sub 2/ pairs in irradiated single crystals of CH/sub 3//sup 13/CO/sub 2/Lix2D/sub 2/0. [Gamma rays

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

Toriyama, K.; Iwasaki, M.

1976-10-01

The CH/sub 3/ radical trapped in irradiated single crystals of CH/sub 3//sup 13/CO/sub 2/Lix2D/sub 2/O has been found to interact with a /sup 13/CO/sub 2/ molecule, which is formed from the C--C bond breakage as a counterpart. The /sup 13/C superhyperfine coupling tensor was determined to be (-4.0, -3.3, -3.5) G. The /sup 13/CO/sub 2/ molecule is located in the direction of the unpaired electron orbital of CH/sub 3/ with the molecular axis perpendicular to it. The spectrum arising from the electron excess center CH/sub 3/ /sup 13/CO/sub 2//sup 2 -/ was also detected together with the CH/sub 3/ radical.more » Our results indicate that the CH/sub 3/xxx/sup 13/CO/sub 2/ pair is essentially a positive hole center formed from one electron loss followed by the C--C bond breakage. (AIP)« less

Effects of electronic health information technology implementation on nursing home resident outcomes.

PubMed

Pillemer, Karl; Meador, Rhoda H; Teresi, Jeanne A; Chen, Emily K; Henderson, Charles R; Lachs, Mark S; Boratgis, Gabriel; Silver, Stephanie; Eimicke, Joseph P

2012-02-01

To examine the effects of electronic health information technology (HIT) on nursing home residents. The study evaluated the impact of implementing a comprehensive HIT system on resident clinical, functional, and quality of care outcome indicators as well as measures of resident awareness of and satisfaction with the technology. The study used a prospective, quasi-experimental design, directly assessing 761 nursing home residents in 10 urban and suburban nursing homes in the greater New York City area. No statistically significant impact of the introduction of HIT on residents was found on any outcomes, with the exception of a significant negative effect on behavioral symptoms. Residents' subjective assessment of the HIT intervention were generally positive. The absence of effects on most indicators is encouraging for the future development of HIT in nursing homes. The single negative finding suggests that further investigation is needed on possible impact on resident behavior. © The Author(s) 2012

Learning crisis resource management: Practicing versus an observational role in simulation training - a randomized controlled trial.

PubMed

Lai, Anita; Haligua, Alexis; Dylan Bould, M; Everett, Tobias; Gale, Mark; Pigford, Ashlee-Ann; Boet, Sylvain

2016-08-01

Simulation training has been shown to be an effective way to teach crisis resource management (CRM) skills. Deliberate practice theory states that learners need to actively practice so that learning is effective. However, many residency programs have limited opportunities for learners to be "active" participants in simulation exercises. This study compares the effectiveness of learning CRM skills when being an active participant versus being an observer participant in simulation followed by a debriefing. Participants were randomized to two groups: active or observer. Active participants managed a simulated crisis scenario (pre-test) while paired observer participants viewed the scenario via video transmission. Then, a trained instructor debriefed participants on CRM principles. On the same day, each participant individually managed another simulated crisis scenario (post-test) and completed a post-test questionnaire. Two independent, blinded raters evaluated all videos using the Ottawa Global Rating Scale (GRS). Thirty-nine residents were included in the analysis. Normally distributed data were analyzed using paired and unpaired t-tests. Inter-rater reliability was 0.64. Active participants significantly improved from pre-test to post-test (P=0.015). There was no significant difference between the post-test performance of active participants compared to observer participants (P=0.12). We found that learning CRM principles was not superior when learners were active participants compared to being observers followed by debriefing. These findings challenge the deliberate practice theory claiming that learning requires active practice. Assigning residents as observers in simulation training and involving them in debriefing is still beneficial. Copyright © 2016 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

Value of fundamentals of laparoscopic surgery training in a fourth-year medical school advanced surgical skills elective.

PubMed

Edelman, David A; Mattos, Mark A; Bouwman, David L

2012-10-01

Few data are available describing the benefits of initiating fundamentals of laparoscopic surgery (FLS) training during medical school. We hypothesized that an intense 1-month surgical skills elective that included FLS task training for fourth-year medical students (MS4s) would result in performance levels indistinguishable from graduating chief residents (PGY5) who had received clinical skill training and access to self-guided FLS curriculum. From July 2007 through June 2011, 114 MS4s participated in a 1-month advanced surgical skills elective. The curriculum for the elective included cadaver dissections, patient management presentations, and surgical skill training (open surgical skills and basic laparoscopic skills modules performed on FLS trainers and virtual reality laparoscopic simulators). From June 2009 through June 2011, 21 PGY5s graduated who had never received formalized FLS skills training. These residents were tested on FLS by a certified proctor and the results recorded. The performance outcome measure was task completion time. Unpaired Student's t-test was used to compare the performance measures for each group. All PGY5s achieved FLS certification on their first attempt and completed enough cases for graduation. The MS4 group showed significantly better performance than the PGY5 group in the peg transfer and circle cut (P < 0.05). No difference was seen in the knot tying tasks between the two groups (P > 0.05) Incorporating FLS training into a 1 month-long medical school surgery elective enabled MS4s to achieve FLS performance similar to, or better than, the performance achieved by PGY5 surgery residents. We support the integration of FLS skills task training as a standard part of the skills training curriculum for medical students. Copyright © 2012 Elsevier Inc. All rights reserved.

Quantifying quality in DNA self-assembly

PubMed Central

Wagenbauer, Klaus F.; Wachauf, Christian H.; Dietz, Hendrik

2014-01-01

Molecular self-assembly with DNA is an attractive route for building nanoscale devices. The development of sophisticated and precise objects with this technique requires detailed experimental feedback on the structure and composition of assembled objects. Here we report a sensitive assay for the quality of assembly. The method relies on measuring the content of unpaired DNA bases in self-assembled DNA objects using a fluorescent de-Bruijn probe for three-base ‘codons’, which enables a comparison with the designed content of unpaired DNA. We use the assay to measure the quality of assembly of several multilayer DNA origami objects and illustrate the use of the assay for the rational refinement of assembly protocols. Our data suggests that large and complex objects like multilayer DNA origami can be made with high strand integration quality up to 99%. Beyond DNA nanotechnology, we speculate that the ability to discriminate unpaired from paired nucleic acids in the same macromolecule may also be useful for analysing cellular nucleic acids. PMID:24751596

The human foramen magnum--normal anatomy of the cisterna magna in adults.

PubMed

Whitney, Nathaniel; Sun, Hai; Pollock, Jeffrey M; Ross, Donald A

2013-11-01

The goal of this study was to radiologically describe the anatomical characteristics of the cisterna magna (CM) with regard to presence, dimension, and configuration. In this retrospective study, 523 records were reviewed. We defined five CM types, the range of which covered all normal variants found in the study population. Characteristics of the CM were recorded and correlations between various posterior fossa dimensions and CM volume determined. There were 268 female (mean age 50.9 ± 16.9 years) and 255 male (mean age 54.1 ± 15.8 years) patients. CM volume was smaller in females than in males and correlated with age (Pearson correlation, r = 0.1494, p = 0.0006) and gender (unpaired t test, r (2) = 0.0608, p < 0.0001). Clivus length correlated with CM volume (Pearson correlation, r = 0.211, p < 0.0001) and gender (unpaired t test, r (2) = 0.2428, p < 0.0001). Tentorial angle did not correlate with CM volume (Pearson correlation, r = -0.0609, p < 0.1642) but did correlate with gender (unpaired t test, r (2) = 0.0163, p < 0.0035). The anterior-posterior dimension of cerebrospinal fluid anterior to the brainstem correlated with CM volume (Pearson correlation, r = 0.181, p < 0.0001) and gender (unpaired t test, r (2) = 0.0205, p = 0.001). The anatomical description and simple classification system we define allows for a more precise description of posterior fossa anatomy and could potentially contribute to the understanding of Chiari malformation anatomy and management.

EGO-1, a Putative RNA-Dependent RNA Polymerase, Is Required for Heterochromatin Assembly on Unpaired DNA during C. elegans Meiosis

PubMed Central

Maine, Eleanor M.; Hauth, Jessica; Ratliff, Thomas; Vought, Valarie E.; She, Xingyu; Kelly, William G.

2014-01-01

Summary During meiosis in C. elegans, unpaired chromosomes and chromosomal regions accumulate high levels of histone H3 lysine 9 dimethylation (H3K9me2), a modification associated with facultative heterochromatin assembly and the resulting transcriptional silencing [1, 2]. Meiotic silencing of unpaired DNA may be a widely conserved genome defense mechanism [3–5]. The mechanisms of meiotic silencing remain unclear, although both transcriptional and posttranscriptional processes are implicated [3–5]. Cellular RNA-dependent RNA polymerases (RdRPs) function in development and RNA-mediated silencing in many species [3, 6, 7] and in heterochromatin assembly in S. pombe [3, 8]. There are four C. elegans RdRPs, including two with known germline functions. EGO-1 is required for fertility and robust germline RNAi [9–11]. RRF-3 acts genetically to repress RNAi and is required for normal meiosis and spermatogenesis at elevated temperatures [12] (S. L’Hernault, personal communication). Among C. elegans RdRPs, we find that only EGO-1 is required for H3K9me2 enrichment on unpaired chromosomal regions during meiosis. This H3K9me2 enrichment does not require Dicer or Drosha nuclease or any of several other proteins required for RNAi. ego-1 interacts genetically with him-17, another regulator of chromatin and meiosis [13], to promote germ-line development. We conclude that EGO-1 is an essential component of meiotic silencing in C. elegans. PMID:16271877

The influence of residents' behaviour on waste electrical and electronic equipment collection effectiveness.

PubMed

Nowakowski, Piotr

2016-11-01

Government agencies have implemented regulations to reduce the volume of waste electrical and electronic equipment to protect the environment and encourage recycling. The effectiveness of systems through which waste electrical and electronic equipment is collected and recycled depends on (a) the development and operation of new programmes to process this material and (b) on information dissemination programmes aimed at manufacturers, retail sellers, and the consuming public. This study analyses these two elements. The main focus is to better understand household residents' behaviour in regards to the proper methods of handling waste electrical and electronic equipment and possible storage of the obsolete equipment that brings disturbances with collection of the waste equipment. The study explores these issues depending on size of municipality and the household residents' knowledge about legal methods of post-consumer management of waste electrical and electronic equipment in Poland, where the collection rate of that type of waste is about 40% of the total mass of waste electrical and electronic equipment appearing in the market.The research was informed by various sources of information, including non-government organisations, Inspectorate of Environmental Protection and Central Statistics Office in Poland, questionnaires, and interviews with the household residents. The questionnaires were distributed to daytime and vocational students from different universities and the customers of an electronic equipment superstore. The results show that a resident's behaviour in regards to the handling of obsolete waste electrical and electronic equipment can significantly reduce the collection rate, especially when the waste is discarded improperly - mixed with municipal waste or sold in scrapyards. It is possible to identify points that are necessary to be improved to achieve a higher collection rate. © The Author(s) 2016.

Measurement of laser activated electron tunneling from semiconductor zinc oxide to adsorbed organic molecules by a matrix assisted laser desorption ionization mass spectrometer.

PubMed

Zhong, Hongying; Fu, Jieying; Wang, Xiaoli; Zheng, Shi

2012-06-04

Measurement of light induced heterogeneous electron transfer is important for understanding of fundamental processes involved in chemistry, physics and biology, which is still challenging by current techniques. Laser activated electron tunneling (LAET) from semiconductor metal oxides was observed and characterized by a MALDI (matrix assisted laser desorption ionization) mass spectrometer in this work. Nanoparticles of ZnO were placed on a MALDI sample plate. Free fatty acids and derivatives were used as models of organic compounds and directly deposited on the surface of ZnO nanoparticles. Irradiation of UV laser (λ=355 nm) with energy more than the band gap of ZnO produces ions that can be detected in negative mode. When TiO(2) nanoparticles with similar band gap but much lower electron mobility were used, these ions were not observed unless the voltage on the sample plate was increased. The experimental results indicate that laser induced electron tunneling is dependent on the electron mobility and the strength of the electric field. Capture of low energy electrons by charge-deficient atoms of adsorbed organic molecules causes unpaired electron-directed cleavages of chemical bonds in a nonergodic pathway. In positive detection mode, electron tunneling cannot be observed due to the reverse moving direction of electrons. It should be able to expect that laser desorption ionization mass spectrometry is a new technique capable of probing the dynamics of electron tunneling. LAET offers advantages as a new ionization dissociation method for mass spectrometry. Copyright © 2012 Elsevier B.V. All rights reserved.

Teaching residents screening, brief intervention, and referral to treatment (SBIRT) skills for alcohol use: Using chart-stimulated recall to assess curricular impact.

PubMed

Wamsley, Maria A; Steiger, Scott; Julian, Katherine A; Gleason, Nathaniel; O'Sullivan, Patricia S; Guy, Michelle; Satterfield, Jason M

2016-01-01

Screening, brief intervention, and referral to treatment (SBIRT) improves identification and intervention for patients at risk for developing an alcohol use disorder (AUD). Residency curriculum is designed to teach SBIRT skills, but resources are needed to promote skill implementation. The electronic health record (EHR) can facilitate implementation through integration of decision-support tools. The authors developed electronic tools to facilitate documentation of alcohol assessment and brief intervention and to reinforce skills from an SBIRT curriculum. This prospective cohort study assessed primary care internal medicine residents' use of SBIRT skills and EHR tools in practice using chart-stimulated recall (CSR). Postgraduate year 2 and 3 residents received a 5-hour SBIRT curriculum with skills practice and instruction on SBIRT electronic tools. Participants were then given a list of their patients seen in a 1-year period who were drinking at/above the recommended limit. Trainees selected 3 patients to review with a faculty member in a CSR. Faculty used a 24-item chart checklist to assess application of SBIRT skills and electronic tool use and met with residents to complete a CSR interview. CSR interview notes were analyzed qualitatively to understand application of SBIRT skills and EHR tool use. Eighteen of 20 residents participated in the CSR, and 5 faculty reviewed 46 patient charts. Residents documented alcohol use (84.2% of charts) and assessment of quantity/frequency of use (71.0%) but were less likely to document assessment for an AUD (34%), an appropriate plan (50.0%), or follow-up (55%). Few residents used EHR tools. Residents reported barriers in addressing alcohol use, including lack of knowledge, patient barriers, and time constraints. More intensive training in SBIRT with opportunities for practice and feedback may be necessary for residents to consistently apply SBIRT skills in practice. EHR tools need to be better integrated into the clinic workflow in order to be useful.

Ferromagnetism induced by point defect in Janus monolayer MoSSe regulated by strain engineering

NASA Astrophysics Data System (ADS)

Meng, Ming; Li, Tinghui; Li, Shaofeng; Liu, Kuili

2018-03-01

The formation and regulation of magnetism dependent on introduced defects in the Janus MoSSe monolayer has attracted much attention because of its potential application in spintronics. Here, we present a theoretical study of defect formation in the MoSSe monolayer and its introduced magnetism under external strain. The tensile deformation induced by external strain not only leads to decreases in defect formation energy, but also enhances magnetic characteristics. However, as compressed deformation increases, the magnetism in the structure induced by Se or S defects remains unchanged because this microstructural deformation adequately spin polarizes unpaired electrons of neighboring Mo atoms. Our results suggest the use of point defect and strain engineering in the Janus MoSSe monolayer for spintronics applications.

Lepton-rich cold QCD matter in protoneutron stars

NASA Astrophysics Data System (ADS)

Jiménez, J. C.; Fraga, E. S.

2018-05-01

We investigate protoneutron star matter using the state-of-the-art perturbative equation of state for cold and dense QCD in the presence of a fixed lepton fraction in which both electrons and neutrinos are included. Besides computing the modifications in the equation of state due to the presence of trapped neutrinos, we show that stable strange quark matter has a more restricted parameter space. We also study the possibility of nucleation of unpaired quark matter in the core of protoneutron stars by matching the lepton-rich QCD pressure onto a hadronic equation of state, namely TM1 with trapped neutrinos. Using the inherent dependence of perturbative QCD on the renormalization scale parameter, we provide a measure of the uncertainty in the observables we compute.

Investigation of Prussian Blue Analogs by XMCD at the K-edge of transition metals

NASA Astrophysics Data System (ADS)

Bordage, A.; Nataf, L.; Baudelet, F.; Bleuzen, A.

2016-05-01

Despite transition metal (TM) K-edge x-ray magnetic circular dichroism (XMCD) seems an interesting tool to get magnetic and structural information at the atomic scale, the effects originating this signal are still poorly understood. We thus initiated a deep investigation of the TM K-edge XMCD using Prussian Blue analogs (PBA) as model-compounds. In a recent study of the NiFe PBA family, we demonstrated that the XMCD signals at the TM K-edges strongly vary with external (mechanical) or internal (chemical) pressure and so that they are highly sensitive to small structural distortions. Following these first results, we extended this approach to the MnFe and CoFe families to evaluate the effect of electronic parameters (number of unpaired electrons of the M II TM) on the XMCD signal. All the results set milestones in the disentanglement of the components originating the XMCD signals at the K-edge of TM and will eventually help in a better understanding of the photomagnetic properties of PBAs.

Rapid screening for anthocyanins in cane sugars using ESR spectroscopy.

PubMed

Thamaphat, Kheamrutai; Goodman, Bernard A; Limsuwan, Pichet; Smith, Siwaporn Meejoo

2015-03-15

Anthocyanin, which is soluble in water and released into sugar steam during extraction, was investigated in this study. The anthocyanin content in refined sugar, plantation white sugar, soft brown sugar and raw sugar was determined using electron spin resonance (ESR) spectroscopy, which was operated at room temperature, and compared with spectra from standard anthocyanin. The ESR spectra of red and violet anthocyanins was predominantly g ≈ 2.0055, which corresponded to an unpaired electron located in the pyrylium ring. Signals for Fe(III) and Mn(II), which naturally occur in plants, were found in raw sugar, soft brown sugar and standard anthocyanin but were absent from refined sugar and plantation white sugar due to the refining process. In addition, the ESR results were correlated with the apparent colour of the sugar, which was determined using the method of the International Commission for Uniform Methods of Sugar Analysis and inductively coupled plasma optical emission spectroscopy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Polarized proton spin density images the tyrosyl radical locations in bovine liver catalase.

PubMed

Zimmer, Oliver; Jouve, Hélène M; Stuhrmann, Heinrich B

2016-09-01

A tyrosyl radical, as part of the amino acid chain of bovine liver catalase, supports dynamic proton spin polarization (DNP). Finding the position of the tyrosyl radical within the macromolecule relies on the accumulation of proton polarization close to it, which is readily observed by polarized neutron scattering. The nuclear scattering amplitude due to the polarization of protons less than 10 Å distant from the tyrosyl radical is ten times larger than the amplitude of magnetic neutron scattering from an unpaired polarized electron of the same radical. The direction of DNP was inverted every 5 s, and the initial evolution of the intensity of polarized neutron scattering after each inversion was used to identify those tyrosines which have assumed a radical state. Three radical sites, all of them close to the molecular centre and the haem, appear to be equally possible. Among these is tyr-369, the radical state of which had previously been proven by electron paramagnetic resonance.

An ESR study of the stable radical in a γ-irradiated single crystal of 17α-dydroxy-progesterone

NASA Astrophysics Data System (ADS)

Krzyminiewski, R.; Pietrzak, J.; Konopka, R.

1990-11-01

Electron spin resonance spectroscopy was used to investigate γ-radiation damage of 17α-hydroxy-progesterone molecules in a single crystal. Two types of radicals with different rates of recombination were observed and a definite structure was assigned to the specimen by analyzing the orientational variation of the spectra. The unpaired electron of the radical is delocalized in the 2 pz orbitals of the C(6), C(4) and C(3) atoms, giving rise to a hyperfine spectrum by interaction with two equivalent α-protons in positions 4 and 6 and with two non-equivalent β-protons attached to C(7). The hyperfine coupling tensors are reported, together with the g tensor of the radical. The presence of additional intermolecular interactions caused by hydrogen bonding between O(3) and HO(17) of two molecules does not change the type of radical (which is the same as the stable radical in a γ-irradiated single crystal of progesterone) but does increase the hyperfine coupling anisotropy.

Unusual ion UO(4)(-) formed upon collision induced dissociation of [UO(2)(NO(3))(3)](-), [UO(2)(ClO(4))(3)](-), [UO(2)(CH(3)COO)(3)](-) ions.

PubMed

Sokalska, Marzena; Prussakowska, Małgorzata; Hoffmann, Marcin; Gierczyk, Błazej; Frański, Rafał

2010-10-01

The following ions [UO(2)(NO(3))(3)](-), [UO(2)(ClO(4))(3)](-), [UO(2)(CH(3)COO)(3)](-) were generated from respective salts (UO(2)(NO(3))(2), UO(2)(ClO(4))(3), UO(2)(CH(3)COO)(2)) by laser desorption/ionization (LDI). Collision induced dissociation of the ions has led, among others, to the formation of UO(4)(-) ion (m/z 302). The undertaken quantum mechanical calculations showed this ion is most likely to possess square planar geometry as suggested by MP2 results or strongly deformed geometry in between tetrahedral and square planar as indicated by DFT results. Interestingly, geometrical parameters and analysis of electron density suggest it is an U(VI) compound, in which oxygen atoms bear unpaired electron and negative charge. Copyright © 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

Rare-earth-free high energy product manganese-based magnetic materials.

PubMed

Patel, Ketan; Zhang, Jingming; Ren, Shenqiang

2018-06-14

The constant drive to replace rare-earth metal magnets has initiated great interest in an alternative. Manganese (Mn) has emerged to be a potential candidate as a key element in rare-earth-free magnets. Its five unpaired valence electrons give it a large magnetocrystalline energy and the ability to form several intermetallic compounds. These factors have led Mn-based magnets to be a potential replacement for rare-earth permanent magnets for several applications, such as efficient power electronics, energy generators, magnetic recording and tunneling applications, and spintronics. For past few decades, Mn-based magnets have been explored in many different forms, such as bulk magnets, thin films, and nanoparticles. Here, we review the recent progress in the synthesis and structure-magnetic property relationships of Mn-based rare-earth-free magnets (MnBi, MnAl and MnGa). Furthermore, we discuss their potential to replace rare-earth magnetic materials through the control of their structure and composition to achieve the theoretically predicted magnetic properties.

24 CFR 902.51 - Updating of public housing unit address information.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Service and Satisfaction § 902.51 Updating of public housing unit address information. (a) Electronic updating. The survey process for the Resident Service and Satisfaction Indicator is dependent upon... any points for the PHAS Resident Service and Satisfaction Indicator. (c) Electronic updating of the...

An evaluation of the availability, accessibility, and quality of online content of vascular surgery training program websites for residency and fellowship applicants.

PubMed

Huang, Bryant Y; Hicks, Taylor D; Haidar, Georges M; Pounds, Lori L; Davies, Mark G

2017-12-01

Vascular surgery residency and fellowship applicants commonly seek information about programs from the Internet. Lack of an effective web presence curtails the ability of programs to attract applicants, and in turn applicants may be unable to ascertain which programs are the best fit for their career aspirations. This study was designed to evaluate the presence, accessibility, comprehensiveness, and quality of vascular surgery training websites (VSTW). A list of accredited vascular surgery training programs (integrated residencies and fellowships) was obtained from four databases for vascular surgery education: the Accreditation Council for Graduate Medical Education, Electronic Residency Application Service, Fellowship and Residency Electronic Interactive Database, and Society for Vascular Surgery. Programs participating in the 2016 National Resident Matching Program were eligible for study inclusion. Accessibility of VSTW was determined by surveying the Accreditation Council for Graduate Medical Education, Electronic Residency Application Service, and Fellowship and Residency Electronic Interactive Database for the total number of programs listed and for the presence or absence of website links. VSTW were analyzed for the availability of recruitment and education content items. The quality of VSTW was determined as a composite of four dimensions: content, design, organization, and user friendliness. Percent agreements and kappa statistics were calculated for inter-rater reliability. Eighty-nine of the 94 fellowship (95%) and 45 of the 48 integrated residencies (94%) programs participating in the 2016 Match had a VSTW. For program recruitment, evaluators found an average of 12 of 32 content items (35.0%) for fellowship programs and an average of 12 of 32 (37%) for integrated residencies. Only 47.1% of fellowship programs (53% integrated residencies) specified the number of positions available for the 2016 Match, 20% (13% integrated residencies) indicated alumni career placement, 34% (38% integrated residencies) supplied interview dates, and merely 17% (18% integrated residencies) detailed the selection process. For program education, fellowship websites provided an average of 5.1 of 15 content items (34.0%), and integrated residency websites provided 5 of 14 items (34%). Of the fellowship programs, 66% (84.4% integrated residencies) provided a rotation schedule, 65% (56% integrated residencies) detailed operative experiences, 38% (38% integrated residencies) posted conference schedules, and just 16% (28.9% integrated residencies) included simulation training. The web presence of vascular surgery training programs lacks sufficient accessibility, content, organization, design, and user friendliness to allow applicants to access information that informs them sufficiently. There are opportunities to more effectively use VSTW for the benefit of training programs and prospective applicants. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Benefits, costs, and determinants of dominance in American black ducks

USGS Publications Warehouse

Hepp, G.R.

1989-01-01

Behavioural dominance was studied in captive American black ducks (Anas rubripes) during October-December 1984. Eighty ducks were marked individually, and groups of 10 ducks consisting of 5 adults (3 males and 2 females) and 5 juveniles (3 males and 2 females) were assigned to each of 8 experimental pens. Ducks in 4 pens received an ad libitum diet, and ducks in the other 4 pens were given a restricted diet. Dominance structure within pens was linear. Adults were dominant to young, and body mass had no influence on dominance rank. The effect of sex on dominance rank was age-specific. Adult males were dominant to adult females and to young black ducks of both sexes; however, dominance rank of young males did not differ from adult or young females. Paired adults were dominant to unpaired adults and to young individuals that were either paired or unpaired. Paired young black ducks were similar in dominance rank to unpaired adults and unpaired young indicating that pairing did not make these individuals more dominant. Ducks on the restricted diet gained less body mass than ducks on the ad libitum diet, but dominant and subordinate black ducks within treatment groups experienced similar changes in body mass during the early winter. Dominant black ducks interacted more frequently and were more likely to form pair bonds than subordinates, thus higher energy costs of dominant individuals may explain the poor relationship between physical condition and dominance rank. There was a significant positive association between the dominance ranks of pair members.

Novel Proteins Required for Meiotic Silencing by Unpaired DNA and siRNA Generation in Neurospora crassa

PubMed Central

Hammond, Thomas M.; Xiao, Hua; Boone, Erin C.; Decker, Logan M.; Lee, Seung A.; Perdue, Tony D.; Pukkila, Patricia J.; Shiu, Patrick K. T.

2013-01-01

During meiosis in the filamentous fungus Neurospora crassa, unpaired genes are identified and silenced by a process known as meiotic silencing by unpaired DNA (MSUD). Previous work has uncovered six proteins required for MSUD, all of which are also essential for meiotic progression. Additionally, they all localize in the perinuclear region, suggesting that it is a center of MSUD activity. Nevertheless, at least a subset of MSUD proteins must be present inside the nucleus, as unpaired DNA recognition undoubtedly takes place there. In this study, we identified and characterized two new proteins required for MSUD, namely SAD-4 and SAD-5. Both are previously uncharacterized proteins specific to Ascomycetes, with SAD-4 having a range that spans several fungal classes and SAD-5 seemingly restricted to a single order. Both genes appear to be predominantly expressed in the sexual phase, as molecular study combined with analysis of publicly available mRNA-seq datasets failed to detect significant expression of them in the vegetative tissue. SAD-4, like all known MSUD proteins, localizes in the perinuclear region of the meiotic cell. SAD-5, on the other hand, is found in the nucleus (as the first of its kind). Both proteins are unique compared to previously identified MSUD proteins in that neither is required for sexual sporulation. This homozygous-fertile phenotype uncouples MSUD from sexual development and allows us to demonstrate that both SAD-4 and SAD-5 are important for the production of masiRNAs, which are the small RNA molecules associated with meiotic silencing. PMID:23502675

Specific interaction of mutant p53 with regions of matrix attachment region DNA elements (MARs) with a high potential for base-unpairing

PubMed Central

Will, Katrin; Warnecke, Gabriele; Wiesmüller, Lisa; Deppert, Wolfgang

1998-01-01

Mutant, but not wild-type p53 binds with high affinity to a variety of MAR-DNA elements (MARs), suggesting that MAR-binding of mutant p53 relates to the dominant-oncogenic activities proposed for mutant p53. MARs recognized by mutant p53 share AT richness and contain variations of an AATATATTT “DNA-unwinding motif,” which enhances the structural dynamics of chromatin and promotes regional DNA base-unpairing. Mutant p53 specifically interacted with MAR-derived oligonucleotides carrying such unwinding motifs, catalyzing DNA strand separation when this motif was located within a structurally labile sequence environment. Addition of GC-clamps to the respective MAR-oligonucleotides or introducing mutations into the unwinding motif strongly reduced DNA strand separation, but supported the formation of tight complexes between mutant p53 and such oligonucleotides. We conclude that the specific interaction of mutant p53 with regions of MAR-DNA with a high potential for base-unpairing provides the basis for the high-affinity binding of mutant p53 to MAR-DNA. PMID:9811860

Sequence-specific activation of the DNA sensor cGAS by Y-form DNA structures as found in primary HIV-1 cDNA.

PubMed

Herzner, Anna-Maria; Hagmann, Cristina Amparo; Goldeck, Marion; Wolter, Steven; Kübler, Kirsten; Wittmann, Sabine; Gramberg, Thomas; Andreeva, Liudmila; Hopfner, Karl-Peter; Mertens, Christina; Zillinger, Thomas; Jin, Tengchuan; Xiao, Tsan Sam; Bartok, Eva; Coch, Christoph; Ackermann, Damian; Hornung, Veit; Ludwig, Janos; Barchet, Winfried; Hartmann, Gunther; Schlee, Martin

2015-10-01

Cytosolic DNA that emerges during infection with a retrovirus or DNA virus triggers antiviral type I interferon responses. So far, only double-stranded DNA (dsDNA) over 40 base pairs (bp) in length has been considered immunostimulatory. Here we found that unpaired DNA nucleotides flanking short base-paired DNA stretches, as in stem-loop structures of single-stranded DNA (ssDNA) derived from human immunodeficiency virus type 1 (HIV-1), activated the type I interferon-inducing DNA sensor cGAS in a sequence-dependent manner. DNA structures containing unpaired guanosines flanking short (12- to 20-bp) dsDNA (Y-form DNA) were highly stimulatory and specifically enhanced the enzymatic activity of cGAS. Furthermore, we found that primary HIV-1 reverse transcripts represented the predominant viral cytosolic DNA species during early infection of macrophages and that these ssDNAs were highly immunostimulatory. Collectively, our study identifies unpaired guanosines in Y-form DNA as a highly active, minimal cGAS recognition motif that enables detection of HIV-1 ssDNA.

AB INITIO STUDY OF THE ELECTRONIC AND MAGNETIC PROPERTIES OF GRAPHENE WITH AND WITHOUT ADSORPTION OF M ATOM (M = C, N, O, F, Cl)

NASA Astrophysics Data System (ADS)

Ismail, Ali I.; Mubarak, A. A.

We present here an ab initio study for the energetic, electronic, magnetic and optical structures of the graphene sheet with and without the adsorption of M atom (M = C, N, O, F, Cl). The calculations are preformed using the full-potential linearized augmented plane wave (FP-LAPW) within the generalized gradient approximation (GGA) to describe the exchange-correlation potential. The calculations show that N prefers the bridge site, while C, O, F and Cl prefer the top site above the graphene sheet. The calculated M-graphene bond length is found to be inversely proportional to the adsorption energy. The hybridization between sp-states of the graphene sheet and M adatom is determined by the analysis of the partial and local density of states (PDOS and TDOS). In case of O and F as adsorbed atoms, graphene sheets show a wide energy band-gap and some significant magnetic moments. The optical properties of the studied sheets are performed in different radiation regions using the real and imaginary parts of the dielectric function. We think that the energetic, electronic, optical and magnetic properties of the M-graphene sheets are governed by two main factors; the number of unpaired valence electrons and the electronegativity of the M atom.

Electron localization in a mixed-valence diniobium benzene complex

DOE PAGES

Gianetti, Thomas L.; Nocton, Grégory; Minasian, Stefan G.; ...

2014-11-11

Reaction of the neutral diniobium benzene complex {[Nb(BDI)N tBu] 2(μ-C 6H 6)} (BDI = N,N'-diisopropylbenzene-β-diketiminate) with Ag[B(C 6F 5) 4] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)N tBu] 2(μ-C 6H 6)}{B(C 6F 5) 4}. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L 3,2-edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment ofmore » a diniobium complex, in which one Nb atom carries a single unpaired electron that is not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.« less

Performance of Certification and Recertification Examinees on Multiple Choice Test Items: Does Physician Age Have an Impact?

PubMed

Shen, Linjun; Juul, Dorthea; Faulkner, Larry R

2016-01-01

The development of recertification programs (now referred to as Maintenance of Certification or MOC) by the members of the American Board of Medical Specialties provides the opportunity to study knowledge base across the professional lifespan of physicians. Research results to date are mixed with some studies finding negative associations between age and various measures of competency and others finding no or minimal relationships. Four groups of multiple choice test items that were independently developed for certification and MOC examinations in psychiatry and neurology were administered to certification and MOC examinees within each specialty. Percent correct scores were calculated for each examinee. Differences between certification and MOC examinees were compared using unpaired t tests, and logistic regression was used to compare MOC and certification examinee performance on the common test items. Except for the neurology certification test items that addressed basic neurology concepts, the performance of the certification and MOC examinees was similar. The differences in performance on individual test items did not consistently favor one group or the other and could not be attributed to any distinguishable content or format characteristics of those items. The findings of this study are encouraging in that physicians who had recently completed residency training possessed clinical knowledge that was comparable to that of experienced physicians, and the experienced physicians' clinical knowledge was equivalent to that of recent residency graduates. The role testing can play in enhancing expertise is described.

Personal digital assistant use in Florida obstetrics and gynecology residency programs.

PubMed

Joy, Saju; Benrubi, Guy

2004-05-01

Improvements in electronic technologies have resulted in affordable, smaller computers that operate at faster speeds. The personal digital assistant (PDA) is a tool that has the potential to enhance residency education by allowing residents immediate access to an abundance of information. This article assesses the current use of this tool at obstetrics and gynecology residency programs in the state of Florida. The authors conducted a statewide survey addressing the general question: is the PDA useful in an obstetrics and gynecology residency training program? Specifically, the authors asked residents how much time was perceived to be saved weekly with the use of this tool, and in what aspect of their training use of this tool was most helpful. At the survey's close, five of seven programs had returned the survey for evaluation. These five institutions included both university- and community-based residency programs. Forty percent of obstetrics and gynecology residents at these programs responded to this questionnaire. Resident responses to the survey revealed that most of the perceived benefit was in maintaining procedural statistics logs, pharmacology reference manuals, and personal clinical protocols. Most responses revealed that only minimal time savings (<2 h/wk) were gained with using this tool. However, many residents felt they were not using this tool to its maximum potential. Nearly 90% of those who responded felt that the PDA should be available at residency programs and anticipated using it after completing residency. This study posed the question of PDA usefulness at obstetric and gynecology residency programs in the state of Florida. Although not all programs provided their residents with a PDA, 95% of the respondents revealed that they owned one of these tools. Experience at the authors' institution revealed high expectations for the potential uses of a PDA. Although many residents were not using this tool to its full potential, a PDA tutorial session could educate residents on the many applications available for PDAs, including applications to maintain on-call schedules and sign-out lists, statistics and procedure logs for credentialing and board certification, electronic billing, and electronic prescriptions.

Structure-property relationships: Synthesis and characterization of Perovskite-related transition metal oxides

NASA Astrophysics Data System (ADS)

Whaley, Louis

The fundamental structural component of perovskite-related phases is the octahedrally coordinated transition metal ion, symbolized as BO6 . Corner-sharing networks of BO6 octahedra are present in perovskites and related Ruddlesden-Popper Phases, ABO3 and AO(ABO 3)n, respectively. Face-sharing octahedra arranged into columns are characteristic of hexagonal, perovskite-related phases, and the relationship will be described in detail in Chapter 1. Edge sharing octahedra are characteristic of Keggin- and Lindquist-type polyoxometallates, which at first glance, seem unconnected from perovskites. However, Chapter 1 will show the deep connections among all of the phases mentioned above, by starting with perovskite phases. Temperature- and field-dependent, magnetic and electronic transitions are linked to the structure by overlap of metal d-orbitals with oxygen 2p orbitals, and (in special cases) direct d-d overlap. A mixed-transition metal oxide with two or more type of B ions provides an environment in which dissimilar B-ion orbitals can interact via exchange of charge carriers (hole or electron transport). The general goal in choosing two B ions is to provide an opportunity for the large combined magnetic moment and a low barrier to hopping of charge carriers, achieved by pairing a 3d-ion having 3 to 5 unpaired d-electrons, with a 4d or 5d transition metal ion, having 1 or 2 unpaired electrons, such as Fe(III) and Mo(V), which have compatible reduction potentials (i.e., they can co-exist in the same oxide, and exchange takes place with a low barrier). This research includes the following systems: an n = 2 Ruddlesden-Popper (RP) phase, Sr3Fe5/4Mo3/4O6.9, containing 3-7% Sr2FeMoO6, as intergrowths (not separate crystal grains, by high-resolution transmission electron microscopy), and G-type antiferromagnetism below 150°K and a "partial spin-reorientation transition" by powder neutron diffraction (PND), not previously reported for n = 2 RP phases in the Sr-Fe-Mo-O system; A B-site ordered double perovskite with an unusual a+b+c+ Glazer octahedral tilt system was synthesized, SrFe1/4Re3/4O 3; single crystals of two anhydrous 1-ethyl-3-methylimidazolium (EMI) salts, EMI octamolybdate, (C6H11N2) 4Mo8O26; and EMI decatungstate, (C6H 11N2)4W10O32; and single crystals of an incommensurate modulated phase, "Sr3CoRh2O 9-delta", with a structure comprising two interpenetrating modulated lattices. Properties of the phases are also reported.

Teaching "Global Mental Health:" Psychiatry Residency Directors' Attitudes and Practices regarding International Opportunities for Psychiatry Residents

ERIC Educational Resources Information Center

Belkin, Gary S.; Yusim, Anna; Anbarasan, Deepti; Bernstein, Carol Ann

2011-01-01

Objective: The authors surveyed Psychiatry Residency Training Directors' (RTDs') attitudes about the role and feasibility of international rotations during residency training. Method: A 21-question survey was electronically distributed that explored RTDs' beliefs about the value, use, and availability of international clinical and research…

End-of-Life Care Education for Psychiatric Residents: Attitudes, Preparedness, and Conceptualizations of Dignity

ERIC Educational Resources Information Center

Tait, Glendon R.; Hodges, Brian D.

2009-01-01

Objective: The authors examined psychiatric residents' attitudes, perceived preparedness, experiences, and needs in end-of-life care education. They also examined how residents conceptualized good end-of-life care and dignity. Methods: The authors conducted an electronic survey of 116 psychiatric residents at the University of Toronto. The survey…

Generalized Bose-Einstein Condensation in Superconductivity

NASA Astrophysics Data System (ADS)

de Llano, Manuel

2011-03-01

Unification of the BCS and the Bose-Einstein condensation (BEC) theories is surveyed in detail via a generalized BEC (GBEC) finite-temperature statistical formalism. Its major difference with BCS theory is that it can be diagonalized exactly. Under specified conditions it yields the precise BCS gap equation for all temperatures as well as the precise BCS zero-temperature condensation energy for all couplings, thereby suggesting that a BCS condensate is a BE condensate in a ternary mixture of kinematically independent unpaired electrons coexisting with equally proportioned weakly-bound two-electron and two-hole Cooper pairs. Without abandoning the electron-phonon mechanism in moderately weak coupling it suffices, in principle, to reproduce the unusually high values of Tc (in units of the Fermi temperature TF) of 0.01-0.05 empirically reported in the so-called "exotic" superconductors of the Uemura plot, including cuprates, in contrast to the low values of Tc/TF ≤ 10-3 roughly reproduced by BCS theory for conventional (mostly elemental) superconductors. Replacing the characteristic phonon-exchange Debye temperature by a characteristic magnon-exchange one more than twice in size can lead to a simple interaction model associated with spin-fluctuation-mediated pairing.

Generalized Bose-Einstein Condensation in Superconductivity

NASA Astrophysics Data System (ADS)

de Llano, Manuel

Unification of the BCS and the Bose-Einstein condensation (BEC) theories is surveyed in detail via a generalized BEC (GBEC) finite-temperature statistical formalism. Its major difference with BCS theory is that it can be diagonalized exactly. Under specified conditions it yields the precise BCS gap equation for all temperatures as well as the precise BCS zero-temperature condensation energy for all couplings, thereby suggesting that a BCS condensate is a BE condensate in a ternary mixture of kinematically independent unpaired electrons coexisting with equally proportioned weakly-bound two-electron and two-hole Cooper pairs. Without abandoning the electron-phonon mechanism in moderately weak coupling it suffices, in principle, to reproduce the unusually high values of Tc (in units of the Fermi temperature TF) of 0.01-0.05 empirically reported in the so-called "exotic" superconductors of the Uemura plot, including cuprates, in contrast to the low values of Tc/TF ≤ 10-3 roughly reproduced by BCS theory for conventional (mostly elemental) superconductors. Replacing the characteristic phonon-exchange Debye temperature by a characteristic magnon-exchange one more than twice in size can lead to a simple interaction model associated with spin-fluctuation-mediated pairing.

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

Gianetti, Thomas L.; Nocton, Grégory; Minasian, Stefan G.

Reaction of the neutral diniobium benzene complex {[Nb(BDI)N tBu] 2(μ-C 6H 6)} (BDI = N,N'-diisopropylbenzene-β-diketiminate) with Ag[B(C 6F 5) 4] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)N tBu] 2(μ-C 6H 6)}{B(C 6F 5) 4}. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L 3,2-edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment ofmore » a diniobium complex, in which one Nb atom carries a single unpaired electron that is not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.« less

The impact of a head and neck microvascular fellowship program on otolaryngology resident training.

PubMed

Zender, Chad A; Clancy, Kate; Melki, Sami; Li, Shawn; Fowler, Nicole

2018-01-01

To assess the impact of a microvascular head and neck (H&N) fellowship on senior residents' surgical experience. Retrospective review of Accreditation Council for Graduate Medical Education-generated operative case log reports, retrospective chart review, and electronic survey. A retrospective review of one institution's residents' H&N operative case logs and free flap operative reports was performed to determine changes in key indicator cases (KICs) after the addition of a H&N fellowship. An electronic survey was distributed to senior residents at all U.S. otolaryngology residency programs to determine residents' perceptions of a H&N fellow's impact on their surgical experience. An electronic survey was distributed to senior medical students applying to surgical residencies to explore the perceived impact that a fellowship has on the desirability of a residency program. The average number of each postgraduate year (PGY)5's H&N KIC before and after the addition of the fellowship were: parotidectomy, 19 versus 17.8; neck dissection, 33.2 versus 40.6; oral cavity resection, 15.3 versus 12.6; thyroid/parathyroid, 45.5 versus 45.6; and flaps/grafts, 56.7 versus 42. PGY5 participation as first assistant in free flaps dropped from 78% to 17%; however, residents still participated in some aspect of 45% of the cases. Seventy percent of senior residents reported a positive perception of the H&N fellow on their H&N operative experience. Eighty-nine percent of senior medical student respondents reported a nonnegative perception of a fellowship in their applied field. The addition of a H&N fellowship did not decrease senior residents' H&N KIC, and most senior residents at programs with fellowships report that the fellow has a positive impact on their H&N operative experience. 4. Laryngoscope, 128:52-56, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Electronic collaboration in dermatology resident training through social networking.

PubMed

Meeks, Natalie M; McGuire, April L; Carroll, Bryan T

2017-04-01

The use of online educational resources and professional social networking sites is increasing. The field of dermatology is currently under-utilizing online social networking as a means of professional collaboration and sharing of training materials. In this study, we sought to assess the current structure of and satisfaction with dermatology resident education and gauge interest for a professional social networking site for educational collaboration. Two surveys-one for residents and one for faculty-were electronically distributed via the American Society for Dermatologic Surgery and Association of Professors of Dermatology (APD) listserves. The surveys confirmed that there is interest among dermatology residents and faculty in a dermatology professional networking site with the goal to enhance educational collaboration.

Interactions of SO{sub x} and NO{sub x} with soot

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

Smith, D.M.; Chughtai, A.R.; Konowalchuk, B.K.

1996-10-01

Studies of the adsorption of oxides of sulfur and nitrogen, and their coadsorption, on black carbon in the form of n-hexane soot have been carried out by microgravimetry, EPR and FTIR spectroscopy over a wide range of experimental conditions. The mechanisms of adsorption of O{sub 2} and NO{sub 2} are entirely different, as reflected by adsorption isotherms, the behavior of carbon`s unpaired electrons, the spectral features of surface species formed, mass changes during adsorption-desorption cycles, and an essential lack of competition for surface sites. Significant effects of temperature, water, SO{sub 2} and NO{sub 2} concentration, O{sub 2}, simulated solar radiation,more » and the presence of trace metals, have been observed and interpreted.« less

Suppressing relaxation in superconducting qubits by quasiparticle pumping.

PubMed

Gustavsson, Simon; Yan, Fei; Catelani, Gianluigi; Bylander, Jonas; Kamal, Archana; Birenbaum, Jeffrey; Hover, David; Rosenberg, Danna; Samach, Gabriel; Sears, Adam P; Weber, Steven J; Yoder, Jonilyn L; Clarke, John; Kerman, Andrew J; Yoshihara, Fumiki; Nakamura, Yasunobu; Orlando, Terry P; Oliver, William D

2016-12-23

Dynamical error suppression techniques are commonly used to improve coherence in quantum systems. They reduce dephasing errors by applying control pulses designed to reverse erroneous coherent evolution driven by environmental noise. However, such methods cannot correct for irreversible processes such as energy relaxation. We investigate a complementary, stochastic approach to reducing errors: Instead of deterministically reversing the unwanted qubit evolution, we use control pulses to shape the noise environment dynamically. In the context of superconducting qubits, we implement a pumping sequence to reduce the number of unpaired electrons (quasiparticles) in close proximity to the device. A 70% reduction in the quasiparticle density results in a threefold enhancement in qubit relaxation times and a comparable reduction in coherence variability. Copyright © 2016, American Association for the Advancement of Science.

Use of traditional versus electronic medical-information resources by residents and interns.

PubMed

Phua, Jason; Lim, T K

2007-05-01

Little is known about the information-seeking behaviour of junior doctors, with regard to their use of traditional versus electronic sources of information. To evaluate the amount of time junior doctors spent using various medical-information resources and how useful they perceived these resources to be. A questionnaire study of all residents and interns in a tertiary teaching hospital in July and August 2004. In total, 134 doctors returned the completed questionnaires (response rate 79.8%). They spent the most time using traditional resources like teaching sessions and print textbooks, rating them as most useful. However, electronic resources like MEDLINE, UpToDate, and online review articles also ranked highly. Original research articles were less popular. Residents and interns prefer traditional sources of medical information. Meanwhile, though some electronic resources are rated highly, more work is required to remove the barriers to evidence-based medicine.

Hypertension is associated with greater heat exchange during exercise recovery in a hot environment.

PubMed

Fonseca, S F; Teles, M C; Ribeiro, V G C; Magalhães, F C; Mendonça, V A; Peixoto, M F D; Leite, L H R; Coimbra, C C; Lacerda, A C R

2015-12-01

Individuals with systemic arterial hypertension have a higher risk of heat-related complications. Thus, the aim of this study was to examine the thermoregulatory responses of hypertensive subjects during recovery from moderate-intensity exercise performed in the heat. A total of eight essential hypertensive (H) and eight normotensive (N) male subjects (age=46.5±1.3 and 45.6±1.4 years, body mass index=25.8±0.8 and 25.6±0.6 kg/m2, mean arterial pressure=98.0±2.8 and 86.0±2.3 mmHg, respectively) rested for 30 min, performed 1 h of treadmill exercise at 50% of maximal oxygen consumption, and rested for 1 h after exercise in an environmental chamber at 38°C and 60% relative humidity. Skin and core temperatures were measured to calculate heat exchange parameters. Mean arterial pressure was higher in the hypertensive than in the normotensive subjects throughout the experiment (P<0.05, unpaired t-test). The hypertensive subjects stored less heat (H=-24.23±3.99 W·m-2vs N=-13.63±2.24 W·m-2, P=0.03, unpaired t-test), experienced greater variations in body temperature (H=-0.62±0.05°C vsN=-0.35±0.12°C, P=0.03, unpaired t-test), and had more evaporated sweat (H=-106.1±4.59 W·m-2vs N=-91.15±3.24 W·m-2, P=0.01, unpaired t-test) than the normotensive subjects during the period of recovery from exercise. In conclusion, essential hypertensive subjects showed greater sweat evaporation and increased heat dissipation and body cooling relative to normotensive subjects during recovery from moderate-intensity exercise performed in hot conditions.

Resolution and evolution of the duck-billed platypus karyotype with an X1Y1X2Y2X3Y3X4Y4X5Y5 male sex chromosome constitution

PubMed Central

Rens, Willem; Grützner, Frank; O'Brien, Patricia C. M.; Fairclough, Helen; Graves, Jennifer A. M.; Ferguson-Smith, Malcolm A.

2004-01-01

The platypus (2n = 52) has a complex karyotype that has been controversial over the last three decades. The presence of unpaired chromosomes and an unknown sex-determining system especially has defied attempts at conventional analysis. This article reports on the preparation of chromosome-specific probes from flow-sorted chromosomes and their application in the identification and classification of all platypus chromosomes. This work reveals that the male karyotype has 21 pairs of chromosomes and 10 unpaired chromosomes (E1-E10), which are linked by short regions of homology to form a multivalent chain in meiosis. The female karyotype differs in that five of these unpaired elements (E1, E3, E5, E7, and E9) are each present in duplicate, whereas the remaining five unpaired elements (E2, E4, E6, E8, and E10) are absent. This finding indicates that sex is determined by the alternate segregation of the chain of 10 during spermatogenesis so that equal numbers of sperm bear either one of the two groups of five elements, i.e., five X and five Y chromosomes. Chromosome painting reveals that these X and Y chromosomes contain pairing (XY shared) and differential (X- or Y-specific) segments. Y differential regions must contain male-determining genes, and X differential regions should be dosage-compensated in the female. Two models for the evolution of the sex-determining system are presented. The resolution of the longstanding debate over the platypus karyotype is an important step toward the understanding of mechanisms of sex determination, dosage compensation, and karyotype evolution. PMID:15534209

Does a frozen embryo transfer ameliorate the effect of elevated progesterone seen in fresh transfer cycles?

PubMed

Healy, Mae Wu; Patounakis, George; Connell, Matt T; Devine, Kate; DeCherney, Alan H; Levy, Michael J; Hill, Micah J

2016-01-01

To compare the effect of progesterone (P) on the day of trigger in fresh assisted reproduction technology (ART) transfer cycles versus its effect on subsequent frozen embryo transfer (FET) cycles. Retrospective cohort study. Large private ART practice. Fresh autologous and FET cycles from 2011-2013. None. Live birth. A paired analysis of patients who underwent both a fresh transfer and subsequent FET cycle and an unpaired analysis of data from all fresh transfer cycles and all FET cycles were performed. We analyzed 1,216 paired and 4,124 unpaired cycles, and P was negatively associated with birth in fresh but not FET cycles in all analyses. Interaction testing of P and cycle type indicated P had a different association with birth in fresh versus FET cycles. When P was ≥ 2 ng/mL at the time of trigger, live birth was more likely in FET versus fresh cycles in the paired analysis (47% vs. 10%), in the unpaired analysis (51% vs. 14%), and in unpaired, good blastocyst only transfer subgroup (51% vs. 29%). Live birth was similar in FET cycles, with P ≥ 2 ng/mL versus P < 2 ng/mL (51% vs. 49%). Conversely, live birth was lower in fresh cycles, with P ≥ 2 ng/mL versus P <2 ng/mL (15% vs. 45%). Elevated P levels on the day of trigger during the initial fresh cycle were negatively associated with live birth in the fresh transfer cycles but not in subsequent FET cycles. Freezing embryos and performing a subsequent FET cycle ameliorates the effect of elevated P on live-birth rates. Published by Elsevier Inc.

Resolution and evolution of the duck-billed platypus karyotype with an X1Y1X2Y2X3Y3X4Y4X5Y5 male sex chromosome constitution.

PubMed

Rens, Willem; Grützner, Frank; O'brien, Patricia C M; Fairclough, Helen; Graves, Jennifer A M; Ferguson-Smith, Malcolm A

2004-11-16

The platypus (2n = 52) has a complex karyotype that has been controversial over the last three decades. The presence of unpaired chromosomes and an unknown sex-determining system especially has defied attempts at conventional analysis. This article reports on the preparation of chromosome-specific probes from flow-sorted chromosomes and their application in the identification and classification of all platypus chromosomes. This work reveals that the male karyotype has 21 pairs of chromosomes and 10 unpaired chromosomes (E1-E10), which are linked by short regions of homology to form a multivalent chain in meiosis. The female karyotype differs in that five of these unpaired elements (E1, E3, E5, E7, and E9) are each present in duplicate, whereas the remaining five unpaired elements (E2, E4, E6, E8, and E10) are absent. This finding indicates that sex is determined by the alternate segregation of the chain of 10 during spermatogenesis so that equal numbers of sperm bear either one of the two groups of five elements, i.e., five X and five Y chromosomes. Chromosome painting reveals that these X and Y chromosomes contain pairing (XY shared) and differential (X- or Y-specific) segments. Y differential regions must contain male-determining genes, and X differential regions should be dosage-compensated in the female. Two models for the evolution of the sex-determining system are presented. The resolution of the longstanding debate over the platypus karyotype is an important step toward the understanding of mechanisms of sex determination, dosage compensation, and karyotype evolution.

Process utility in breast biopsy.

PubMed

Swan, J Shannon; Lawrence, William F; Roy, Jessica

2006-01-01

To determine whether the waiting trade-off (WTO) is feasible for differentiating short-term biopsy preferences in an acute situation where anxiety is the symptomatic disease state. 75 women with past experience of either breast core-needle biopsy (CNB), more invasive excisional surgical biopsy (EXB), or both, had telephone WTO assessments. Patients' baseline and test-related anxiety were valued by time trade-off (TTO) used to scale the WTO. Rating scales (RS) were obtained for convergent validity assessment with WTO and TTO. Data were obtained in 38 women who had both CNB and EXB ("paired") and 20 who had CNB only and 16 who had EXB only ("unpaired"). Patients rated only the procedure(s) they experienced. Median paired and mean unpaired WTO scores indicated patients were willing to wait significantly longer to avoid EXB (P = 0.0003, P = 0.0002, respectively). The waiting time difference between EXB and CNB was 2.1 weeks greater in unpaired data than paired data. RS scores comparing the procedures were significantly different only for paired data (P < 0.05). Median TTO preferences for baseline (1.00) and test anxiety (0.93) obtained in 74 patients were significantly different (P < 0.0001) and consistent with RS. Correlation was noted between WTO and RS (-0.307 to -0.453, P = 0.0205 to 0.0001). The median EXB quality-adjusted life years toll (1.5 quality-adjusted life days) calculated from pooled WTO data (paired and unpaired) from 54 patients is near a threshold in a published model. The WTO is feasible for discriminating preferences for short-term health states in an acute medical scenario where it might have been expected to be impracticable.

Resource format preferences across the medical curriculum.

PubMed

Pickett, Keith M

2016-07-01

This research study sought to determine the formats (print or electronic) of articles and book chapters most-preferred by first-year medical students, third-year medical students entering clinical clerkships, and incoming residents and to determine if these preferences change during the course of the medical curriculum. These trends will enable academic health sciences libraries to make appropriate collection development decisions to best cater to their user populations. First-year medical students, third-year medical students, and incoming medical residents were asked to complete a paper survey from September 2014 to June 2015. The survey consisted of five multiple-choice questions, with two questions given space for optional short answers. Quantitative and qualitative responses were collected and calculated using Microsoft Excel. First-year students, third-year students, and incoming residents all preferred to read journal articles and book chapters in print, except in cases where the article or book chapter is under ten pages in length. Although print is preferred, demand for electronic articles and book chapters increases as students progress from undergraduate medical education into residency. The only category where a majority of incoming residents chose an electronic resource was which format they would give to a colleague, if the article or book chapter was critical to the care of an individual patient. The preference for print resources is strong across the medical curriculum, although residents show an increased preference for electronic materials when compared to first- and third-year students. Academic health sciences libraries should take these preferences into account when making decisions regarding collection development.

Applying health information technology and team-based care to residency education.

PubMed

Brown, Kristy K; Master-Hunter, Tara A; Cooke, James M; Wimsatt, Leslie A; Green, Lee A

2011-01-01

Training physicians capable of practicing within the Patient-centered Medical Home (PCMH) is an emerging area of scholarly inquiry within residency education. This study describes an effort to integrate PCMH principles into teaching practices within a university-based residency setting and evaluates the effect on clinical performance. Using participant feedback and clinical data extracted from an electronic clinical quality management system, we retrospectively examined performance outcomes at two family medicine residency clinics over a 7-year period. Instructional approaches were identified and clinical performance patterns analyzed. Alumni ratings of the practice-based curriculum increased following institution of the PCMH model. Clinical performance outcomes indicated improvements in the delivery of clinical care to patients. Implementation of instructional methodologies posed some challenges to residency faculty, particularly in development of consistent scheduling of individualized feedback sessions. Residents required the greatest support and guidance in managing point-of-care clinical reminders during patient encounters. Teaching practices that take into consideration the integration of team-based care and use of electronic health technologies can successfully be used to deliver residency education in the context of the PCMH model. Ongoing assessment provides important information to residency directors and faculty in support of improving the quality of clinical instruction.

Unpaired Majorana modes in Josephson-Junction Arrays with gapless bulk excitations

DOE PAGES

Pino, M.; Tsvelik, A.; Ioffe, L. B.

2015-11-06

In this study, the search for Majorana bound states in solid-state physics has been limited to materials that display a gap in their bulk spectrum. We show that such unpaired states appear in certain quasi-one-dimensional Josephson-junction arrays with gapless bulk excitations. The bulk modes mediate a coupling between Majorana bound states via the Ruderman-Kittel-Yosida-Kasuya mechanism. As a consequence, the lowest energy doublet acquires a finite energy difference. For a realistic set of parameters this energy splitting remains much smaller than the energy of the bulk eigenstates even for short chains of length L~10.

Unpaired 5' ppp-nucleotides, as found in arenavirus double-stranded RNA panhandles, are not recognized by RIG-I.

PubMed

Marq, Jean-Baptiste; Kolakofsky, Daniel; Garcin, Dominique

2010-06-11

Arenavirus and bunyavirus RNA genomes are unusual in that they are found in circular nucleocapsids, presumably due to the annealing of their complementary terminal sequences. Moreover, arenavirus genome synthesis initiates with GTP at position +2 of the template rather than at the precise 3' end (position +1). After formation of a dinucleotide, 5' pppGpC(OH) is then realigned on the template before this primer is extended. The net result of this "prime and realign" mechanism of genome initiation is that 5' pppG is found as an unpaired 5' nucleotide when the complementary genome ends anneal to form a double-stranded (dsRNA) panhandle. Using 5' pppRNA made in vitro and purified so that all dsRNA side products are absent, we have determined that both this 5' nucleotide overhang, as well as mismatches within the dsRNA (as found in some arenavirus genomes), clearly reduce the ability of these model dsRNAs to induce interferon upon transfection into cells. The presence of this unpaired 5' ppp-nucleotide is thus another way that some viruses appear to use to avoid detection by cytoplasmic pattern recognition receptors.

Automated Reporting of Trainee Metrics Using Electronic Clinical Systems.

PubMed

Levin, Jonathan C; Hron, Jonathan

2017-06-01

The Accreditation Council for Graduate Medical Education has called for increased emphasis on reporting objective performance measures to trainees and programs. However, reporting of objective measures, including clinical volume, is largely omitted from training programs. To use automated electronic medical systems at a tertiary pediatric care hospital to create a dashboard that reports objective trainee and program metrics, including clinical volume and diagnoses in a pediatrics residency. We queried an enterprise data warehouse that aggregates data daily from multiple hospital systems to identify patient encounters during which senior pediatrics residents at Boston Children's Hospital had entered documentation over a 9-month period. From this query, we created a filterable dashboard to display clinical volume and diagnosis data by individual resident and in aggregate. A total of 44 of 45 senior residents (98%) in the program were included in analysis. We identified 12 198 patient encounters during which a senior pediatrics resident had entered documentation; these included a median of 332 inpatient encounters per resident, 122 emergency department encounters, and 84 outpatient encounters. The most common diagnoses stratified by clinical site were: inpatient - dehydration (median = 61); emergency department - long-term/current drug therapy (median = 16); and outpatient - encounter for immunization (median = 48). We used electronic health record systems to generate performance dashboards for trainees in a pediatrics residency across different sites of care with reported volume by diagnosis. Our dashboards provide feedback to program leadership regarding individual and aggregate trainee experience and allow individual trainees to compare their clinical exposure to peers.

Frequency of and reasons for pharmacy residents breaching the National Matching Services applicant agreement.

PubMed

Cohen, Victor; Jellinek, Samantha P; Blecker, Michael; Cocchio, Craig; Likourezos, Antonios; Shah, Bupendra

2010-11-01

The frequency of and reasons for pharmacy residents breaching the National Matching Services (NMS) applicant agreement were evaluated. An electronic survey was sent via e-mail to residency program directors of ASHP-accredited postgraduate year 1 pharmacy residencies in the United States. The survey instrument was developed based on an initial pilot survey used to test the clarity and reliability of the questions. The primary objective of the survey was to determine the frequency with which pharmacy residents breach the NMS applicant agreement and fail to report to their assigned site. Characteristics of ASHP- accredited residency programs with residents who breached the NMS agreement and any punitive action taken on these individuals were also analyzed. Of the 636 surveys sent to residency program directors, 302 complete surveys were returned, yielding a response rate of 47.5%. Twenty-six respondents (8.6%) indicated that within the past five years, they had matched candidates who failed to report to their assigned site. Of these respondents, 13 (50%) reported the candidate to ASHP; 11 (44%) took no action. Respondents indicated that they would be comfortable reporting all candidates who breach the NMS agreement to ASHP and placing the candidates' information on a list accessible electronically only to residency program directors. Less than 10% of residency program directors reported having residency candidates who breached the NMS applicant agreement. The majority of these respondents indicated that these residents were not their first choices. The most common reason for candidate withdrawal was family obligation.

Structure and Magnetic Properties of Rare Earth Doped Transparent Alumina

NASA Astrophysics Data System (ADS)

Limmer, Krista; Neupane, Mahesh; Chantawansri, Tanya

Recent experimental studies of rare earth (RE) doped alumina suggest that the RE induced novel phase-dependent structural and magnetic properties. Motivated by these efforts, the effects of RE doping of alpha and theta alumina on the local structure, magnetic properties, and phase stability have been examined in this first principles study. Although a direct correlation between the magnetic field dependent materials properties observed experimentally and calculated from first principles is not feasible because of the applied field and the scale, the internal magnetic properties and other properties of the doped materials are evaluated. The RE dopants are shown to increase the substitutional site volume as well as increasingly distort the site structure as a function of ionic radii. Doping both the alpha (stable) and theta (metastable) phases enhanced the relative stability of the theta phase. The energetic doping cost and internal magnetic moment were shown to be a function of the electronic configuration of the RE-dopant, with magnetic moment directly proportional to the number of unpaired electrons and doping cost being inversely related.

EPR and pulsed ENDOR study of intermediates from reactions of aromatic azides with group 13 metal trichlorides

PubMed Central

Bencivenni, Giorgio; Cesari, Riccardo; Nanni, Daniele; El Mkami, Hassane

2010-01-01

Summary The reactions of group 13 metal trichlorides with aromatic azides were examined by CW EPR and pulsed ENDOR spectroscopies. Complex EPR spectra were obtained from reactions of aluminium, gallium and indium trichlorides with phenyl azides containing a variety of substituents. Analysis of the spectra showed that 4-methoxy-, 3-methoxy- and 2-methoxyphenyl azides all gave ‘dimer’ radical cations [ArNHC6H4NH2]+• and trimers [ArNHC6H4NHC6H4NH2]+• followed by polymers. 4-Azidobenzonitrile, with its electron-withdrawing substituent, did not react. In general the aromatic azides appeared to react most rapidly with AlCl3 but this reagent tended to generate much polymer. InCl3 was the least reactive group 13 halide. DFT computations of the radical cations provided corroborating evidence and suggested that the unpaired electrons were accommodated in extensive π-delocalised orbitals. A mechanism to account for the reductive conversion of aromatic azides to the corresponding anilines and thence to the dimers and trimers is proposed. PMID:21049080

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

Song, Xiaowei; Fagiani, Matias R.; Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, D-04103 Leipzig

We use cryogenic ion trap vibrational spectroscopy in combination with quantum chemical calculations to study the structure of mono- and dialuminum oxide anions. The infrared photodissociation spectra of D{sub 2}-tagged AlO{sub 1-4}{sup −} and Al{sub 2}O{sub 3-6}{sup −} are measured in the region from 400 to 1200 cm{sup −1}. Structures are assigned based on a comparison to simulated harmonic and anharmonic IR spectra derived from electronic structure calculations. The monoaluminum anions contain an even number of electrons and exhibit an electronic closed-shell ground state. The Al{sub 2}O{sub 3-6}{sup −} anions are oxygen-centered radicals. As a result of a delicate balancemore » between localization and delocalization of the unpaired electron, only the BHLYP functional is able to qualitatively describe the observed IR spectra of all species with the exception of AlO{sub 3}{sup −}. Terminal Al–O stretching modes are found between 1140 and 960 cm{sup −1}. Superoxo and peroxo stretching modes are found at higher (1120-1010 cm{sup −1}) and lower energies (850-570 cm{sup −1}), respectively. Four modes in-between 910 and 530 cm{sup −1} represent the IR fingerprint of the common structural motif of dialuminum oxide anions, an asymmetric four-member Al–(O){sub 2}–Al ring.« less

Pilot Study of iPad Incorporation Into Graduate Medical Education.

PubMed

Lobo, Mark J; Crandley, Edwin F; Rumph, Jake S; Kirk, Susan E; Dunlap, Neal E; Rahimi, Asal S; Turner, A Benton; Larner, James M; Read, Paul W

2013-03-01

Increased documentation and charting requirements are challenging for residents, given duty hour limits. Use of mobile electronic devices may help residents complete these tasks efficiently. To collect initial data on usage rates, information technology (IT) support requirements, and resident use of iPads during training. In this pilot study, we provided 12 residents/fellows from various specialties at the University of Virginia with an iPad with IT support. The system used a virtual private network with access to the institution's electronic health record. Participants were allowed to develop their own methods and systems for personalized iPad use, and after 9 months they provided data on the utility of the iPad. Feedback from the IT team also was obtained. Average iPad use was 2.1 h/d (range, 0.5-6 h/d). The average self-reported reduction in administrative work due to the iPad was 2.7 h/wk (range, 0-9 h/wk). A total of 75% (9 of 12) of the users would recommend universal adoption among residents and fellows. More than 90% (11 of 12) of users reported the iPad would improve communication for coordination of care. A total of 68% (8 of 12) of users reported that an iPad facilitated their activities as educators of medical students and junior residents. Residents cited slow data entry into the electronic health record and hospital areas lacking Wi-Fi connectivity as potential drawbacks to iPad use. The IT team reported minimal support time for device setup, maintenance, and upgrades, and limited security risks. The iPad may contribute to increased clinical efficiency, reduced hours spent on administrative tasks, and enhanced educational opportunities for residents, with minimal IT support.

High-Resolution Laser Spectroscopy of Free Radicals in Nearly Degenerate Electronic States

NASA Astrophysics Data System (ADS)

Liu, Jinjun

2017-06-01

Rovibronic structure of molecules in orbitally degenerate electronic states including Renner-Teller (RT) and Jahn-Teller (JT) active molecules has been extensively studied. Less is known about rotational structure of polyatomic molecules in nearly degenerate states, especially those with low (e.g., C_s) symmetry that are subject to the pseudo-Jahn-Teller (pJT) effect. In the case of free radicals, the unpaired electron further complicates energy levels by inducing spin-orbit (SO) and spin-rotation (SR) splittings. Asymmetric deuteration or methyl substitution of C_{3v} free radicals such as CH_3O, CaCH_3, and CaOCH_3 lowers the molecular symmetry, lifts the vibronic degeneracy, and reduces the JT effect to the pJT effect. New spectroscopic models are required to reproduce the rovibronic structure and simulate the experimentally obtained spectra of pJT-active free radicals. It has been found that rotational and fine-structure analysis of spectra involving nearly degenerate states may aid in vibronic analysis and interpretation of effective molecular constants. Especially, SO and Coriolis interactions that couple the two states can be determined accurately from fitting the experimental spectra. Coupling between the two electronic states also affects the intensities of rotational and vibronic transitions. The study on free radicals in nearly degenerate states provides a promising avenue of research which may bridge the gap between symmetry-induced degenerate states and the Born-Oppenheimer (BO) limit of unperturbed electronic states.

Dynamics of 4-oxo-TEMPO-d16-15N nitroxide-propylene glycol system studied by ESR and ESE in liquid and glassy state in temperature range 10-295 K

NASA Astrophysics Data System (ADS)

Goslar, Janina; Hoffmann, Stanislaw K.; Lijewski, Stefan

2016-08-01

ESR spectra and electron spin relaxation of nitroxide radical in 4-oxo-TEMPO-d16-15N in propylene glycol were studied at X-band in the temperature range 10-295 K. The spin-lattice relaxation in the liquid viscous state determined from the resonance line shape is governed by three mechanisms occurring during isotropic molecular reorientations. In the glassy state below 200 K the spin-lattice relaxation, phase relaxation and electron spin echo envelope modulations (ESEEM) were studied by pulse spin echo technique using 2-pulse and 3-pulse induced signals. Electron spin-lattice relaxation is governed by a single non-phonon relaxation process produced by localized oscillators of energy 76 cm-1. Electron spin dephasing is dominated by a molecular motion producing a resonance-type peak in the temperature dependence of the dephasing rate around 120 K. The origin of the peak is discussed and a simple method for the peak shape analysis is proposed, which gives the activation energy of a thermally activated motion Ea = 7.8 kJ/mol and correlation time τ0 = 10-8 s. The spin echo amplitude is strongly modulated and FT spectrum contains a doublet of lines centered around the 2D nuclei Zeeman frequency. The splitting into the doublet is discussed as due to a weak hyperfine coupling of nitroxide unpaired electron with deuterium of reorienting CD3 groups.

Magnetic defects in chemically converted graphene nanoribbons: electron spin resonance investigation

NASA Astrophysics Data System (ADS)

Singamaneni, Srinivasa Rao; Stesmans, Andre; van Tol, Johan; Kosynkin, D. V.; Tour, James M.

2014-04-01

Electronic spin transport properties of graphene nanoribbons (GNRs) are influenced by the presence of adatoms, adsorbates and edge functionalization. To improve the understanding of the factors that influence the spin properties of GNRs, local (element) spin-sensitive techniques such as electron spin resonance (ESR) spectroscopy are important for spintronics applications. Here, we present results of multi-frequency continuous wave (CW), pulse and hyperfine sublevel correlation (HYSCORE) ESR spectroscopy measurements performed on oxidatively unzipped graphene nanoribbons (GNRs), which were subsequently chemically converted (CCGNRs) with hydrazine. ESR spectra at 336 GHz reveal an isotropic ESR signal from the CCGNRs, of which the temperature dependence of its line width indicates the presence of localized unpaired electronic states. Upon functionalization of CCGNRs with 4-nitrobenzene diazonium tetrafluoroborate, the ESR signal is found to be 2 times narrower than that of pristine ribbons. NH3 adsorption/desorption on CCGNRs is shown to narrow the signal, while retaining the signal intensity and g value. The electron spin-spin relaxation process at 10 K is found to be characterized by slow (163 ns) and fast (39 ns) components. HYSCORE ESR data demonstrate the explicit presence of protons and 13C atoms. With the provided identification of intrinsic point magnetic defects such as proton and 13C has been reported, which are roadblocks to spin travel in graphene-based materials, this work could help in advancing the present fundamental understanding on the edge-spin (or magnetic)-based transport properties of CCGNRs.

Prevalence and socio-demographic correlates of dental anxiety among a group of adult patients attending a dental institution in Vadodara city, Gujarat, India.

PubMed

Malvania, Ekta A; Ajithkrishnan, C G

2011-01-01

Anxiety is a subjective state of feelings. Dental anxiety is often reported as a cause of irregular dental attendance, delay in seeking dental care or even avoidance of dental care, resulting in poor oral health related quality of life. To assess the prevalence and socio-demographic correlates of dental anxiety among a group of adult patients attending a dental institution in Vadodara, Gujarat. A total of 150 adult patients waiting in the out-patient Department of Oral Diagnosis of K.M. Shah Dental College and Hospital were included in the study. Subjects were selected by convenience sampling. Dental anxiety was assessed by using Modified Dental Anxiety Scale (MDAS) and self-designed, semi-structured questionnaire incorporating various demographic variables, type and nature of dental treatment. Statistical analysis was done using SPSS version 16. Descriptive analysis, unpaired t-test, one-way analysis of variance (ANOVA) test and multiple logistic regression were applied for statistical analysis. 46% of the participants were dentally anxious. Females were found to be significantly more anxious than males. Subjects residing in villages had significantly more score than those residing in city. Relative influence of age, education, type of dental treatment, and previous dental visit were not significantly associated with dental anxiety. However, those subjects who had past negative dental experience were found to be significantly more anxious. The study shows that dental anxiety was high among study subjects. It is recommended that this issue should be given due importance and addressed in a practical and meaningful manner.

EPR investigation of gamma-irradiated L-citrulline, α-methyl-DL-serine, 3-fluoro-DL-valine and N-acetyl-L-cysteine

NASA Astrophysics Data System (ADS)

Osmanoğlu, Y. Emre; Sütçü, Kerem; Başkan, M. Halim

2017-02-01

The spectroscopic parameters of the paramagnetic species produced in gamma-irradiated L-citrulline, α-methyl-DL-serine, 3-fluoro-DL-valine and N-acetyl-L-cysteine were investigated at room temperature at a dose of 20 kGy by using EPR technique. The paramagnetic species were attributed to NH2CONH(CH2)3ĊNH2COOH, HOCH2ĊCH3COOH and HOĊHCCH3NH2COOH, CH3CH3ĊCHNH2COOH and SHCH2ĊNHCOCH3COOH radicals, respectively. EPR data of the unpaired electron with the environmental protons and 14N nucleus were used to characterize the contributing radicals produced in gamma irradiated compounds. In this paper, the stability of these compounds at room temperature after irradiation was also studied.

Antiferromagnetic S=1/2 spin chain driven by p-orbital ordering in CsO2.

PubMed

Riyadi, Syarif; Zhang, Baomin; de Groot, Robert A; Caretta, Antonio; van Loosdrecht, Paul H M; Palstra, Thomas T M; Blake, Graeme R

2012-05-25

We demonstrate, using a combination of experiment and density functional theory, that orbital ordering drives the formation of a one-dimensional (1D) S=1/2 antiferromagnetic spin chain in the 3D rocksalt structure of cesium superoxide (CsO2). The magnetic superoxide anion (O2(-)) exhibits degeneracy of its 2p-derived molecular orbitals, which is lifted by a structural distortion on cooling. A spin chain is then formed by zigzag ordering of the half-filled superoxide orbitals, promoting a superexchange pathway mediated by the p(z) orbitals of Cs(+) along only one crystal direction. This scenario is analogous to the 3d-orbital-driven spin chain found in the perovskite KCuF3 and is the first example of an inorganic quantum spin system with unpaired p electrons.

OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. III. MEASURES BELOW THE DIFFRACTION LIMIT OF THE WIYN TELESCOPE

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

Horch, Elliott P.; Van Altena, William F.; Howell, Steve B.

2011-06-15

In this paper, we study the ability of CCD- and electron-multiplying-CCD-based speckle imaging to obtain reliable astrometry and photometry of binary stars below the diffraction limit of the WIYN 3.5 m Telescope. We present a total of 120 measures of binary stars, 75 of which are below the diffraction limit. The measures are divided into two groups that have different measurement accuracy and precision. The first group is composed of standard speckle observations, that is, a sequence of speckle images taken in a single filter, while the second group consists of paired observations where the two observations are taken onmore » the same observing run and in different filters. The more recent paired observations were taken simultaneously with the Differential Speckle Survey Instrument, which is a two-channel speckle imaging system. In comparing our results to the ephemeris positions of binaries with known orbits, we find that paired observations provide the opportunity to identify cases of systematic error in separation below the diffraction limit and after removing these from consideration, we obtain a linear measurement uncertainty of 3-4 mas. However, if observations are unpaired or if two observations taken in the same filter are paired, it becomes harder to identify cases of systematic error, presumably because the largest source of this error is residual atmospheric dispersion, which is color dependent. When observations are unpaired, we find that it is unwise to report separations below approximately 20 mas, as these are most susceptible to this effect. Using the final results obtained, we are able to update two older orbits in the literature and present preliminary orbits for three systems that were discovered by Hipparcos.« less

Chronic intermittent hypoxia reduces neurokinin-1 (NK(1)) receptor density in small dendrites of non-catecholaminergic neurons in mouse nucleus tractus solitarius.

PubMed

Lessard, Andrée; Coleman, Christal G; Pickel, Virginia M

2010-06-01

Chronic intermittent hypoxia (CIH) is a frequent concomitant of sleep apnea, which can increase sympathetic nerve activity through mechanisms involving chemoreceptor inputs to the commissural nucleus of the solitary tract (cNTS). These chemosensory inputs co-store glutamate and substance P (SP), an endogenous ligand for neurokinin-1 (NK(1)) receptors. Acute hypoxia results in internalization of NK(1) receptors, suggesting that CIH also may affect the subcellular distribution of NK(1) receptors in subpopulations of cNTS neurons, some of which may express tyrosine hydroxylase, the rate-limiting enzyme for catecholamine synthesis (TH). To test this hypothesis, we examined dual immunolabeling for the NK(1) receptor and TH in the cNTS of male mice subjected to 10days or 35days of CIH or intermittent air. Electron microscopy revealed that NK(1) receptors and TH were almost exclusively localized within separate somatodendritic profiles in cNTS of control mice. In dendrites, immunogold particles identifying NK(1) receptors were prevalent in the cytoplasm and on the plasmalemmal surface. Compared with controls, CIH produced a significant region-specific decrease in the cytoplasmic (10 and 35days, P<0.05, unpaired Student t-test) and extrasynaptic plasmalemmal (35days, P<0.01, unpaired Student t-test) density of NK(1) immunogold particles exclusively in small (<0.1microm) dendrites without TH immunoreactivity. These results suggest that CIH produces a duration-dependent reduction in the availability of NK(1) receptors preferentially in small dendrites of non-catecholaminergic neurons in the cNTS. The implications of our findings are discussed with respect to their potential involvement in the slowly developing hypertension seen in sleep apnea patients. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Chronic intermittent hypoxia reduces neurokinin-1 (NK1) receptor density in small dendrites of non-catecholaminergic neurons in mouse nucleus tractus solitarius

PubMed Central

Lessard, Andrée; Coleman, Christal G.; Pickel, Virginia M.

2010-01-01

Chronic intermittent hypoxia (CIH) is a frequent concomitant of sleep apnea, which can increase sympathetic nerve activity through mechanisms involving chemoreceptor inputs to the commissural nucleus of the solitary tract (cNTS). These chemosensory inputs co-store glutamate and substance P (SP), an endogenous ligand for neurokinin-1 (NK1) receptors. Acute hypoxia results in internalization of NK1 receptors, suggesting that CIH also may affect the subcellular distribution of NK1 receptors in subpopulations of cNTS neurons, some of which may express tyrosine hydroxylase, the rate-limiting enzyme for catecholamine synthesis (TH). To test this hypothesis, we examined dual immunolabeling for the NK1 receptor and TH in the cNTS of male mice subjected to 10 days or 35 days of CIH or intermittent air. Electron microscopy revealed that NK1 receptors and TH were almost exclusively localized within separate somatodendritic profiles in cNTS of control mice. In dendrites, immunogold particles identifying NK1 receptors were prevalent in the cytoplasm and on the plasmalemmal surface. Compared with controls, CIH produced a significant region-specific decrease in the cytoplasmic (10 and 35 days, P< 0.05, unpaired Student t-test) and extrasynaptic plasmalemmal (35 days, P< 0.01, unpaired Student t-test) density of NK1 immunogold particles exclusively in small (<0.1 µm) dendrites without TH immunoreactivity. These results suggest that CIH produces a duration-dependent reduction in the availability of NK1 receptors preferentially in small dendrites of non-catecholaminergic neurons in the cNTS. The implications of our findings are discussed with respect to their potential involvement in the slowly developing hypertension seen in sleep apnea patients. PMID:20206166

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

Ponomarenko, N. S.; Poluektov, O. G.; Bylina, E. J.

High-field electron paramagnetic resonance (HF EPR) has been employed to investigate the primary electron donor electronic structure of Blastochloris viridis heterodimer mutant reaction centers (RCs). In these mutants the amino acid substitution His(M200)Leu or His(L173)Leu eliminates a ligand to the primary electron donor, resulting in the loss of a magnesium in one of the constituent bacteriochlorophylls (BChl). Thus, the native BChl/BChl homodimer primary donor is converted into a BChl/bacteriopheophytin (BPhe) heterodimer. The heterodimer primary donor radical in chemically oxidized RCs exhibits a broadened EPR line indicating a highly asymmetric distribution of the unpaired electron over both dimer constituents. Observed tripletmore » state EPR signals confirm localization of the excitation on the BChl half of the heterodimer primary donor. Theoretical simulation of the triplet EPR lineshapes clearly shows that, in the case of mutants, triplet states are formed by an intersystem crossing mechanism in contrast to the radical pair mechanism in wild type RCs. Photooxidation of the mutant RCs results in formation of a BPhe anion radical within the heterodimer pair. The accumulation of an intradimer BPhe anion is caused by the substantial loss of interaction between constituents of the heterodimer primary donor along with an increase in the reduction potential of the heterodimer primary donor D/D{sup +} couple. This allows oxidation of the cytochrome even at cryogenic temperatures and reduction of each constituent of the heterodimer primary donor individually. Despite a low yield of primary donor radicals, the enhancement of the semiquinone-iron pair EPR signals in these mutants indicates the presence of kinetically viable electron donors.« less

Reactive Oxygen Species Production by Forward and Reverse Electron Fluxes in the Mitochondrial Respiratory Chain

PubMed Central

Selivanov, Vitaly A.; Votyakova, Tatyana V.; Pivtoraiko, Violetta N.; Zeak, Jennifer; Sukhomlin, Tatiana; Trucco, Massimo; Roca, Josep; Cascante, Marta

2011-01-01

Reactive oxygen species (ROS) produced in the mitochondrial respiratory chain (RC) are primary signals that modulate cellular adaptation to environment, and are also destructive factors that damage cells under the conditions of hypoxia/reoxygenation relevant for various systemic diseases or transplantation. The important role of ROS in cell survival requires detailed investigation of mechanism and determinants of ROS production. To perform such an investigation we extended our rule-based model of complex III in order to account for electron transport in the whole RC coupled to proton translocation, transmembrane electrochemical potential generation, TCA cycle reactions, and substrate transport to mitochondria. It fits respiratory electron fluxes measured in rat brain mitochondria fueled by succinate or pyruvate and malate, and the dynamics of NAD+ reduction by reverse electron transport from succinate through complex I. The fitting of measured characteristics gave an insight into the mechanism of underlying processes governing the formation of free radicals that can transfer an unpaired electron to oxygen-producing superoxide and thus can initiate the generation of ROS. Our analysis revealed an association of ROS production with levels of specific radicals of individual electron transporters and their combinations in species of complexes I and III. It was found that the phenomenon of bistability, revealed previously as a property of complex III, remains valid for the whole RC. The conditions for switching to a state with a high content of free radicals in complex III were predicted based on theoretical analysis and were confirmed experimentally. These findings provide a new insight into the mechanisms of ROS production in RC. PMID:21483483

Spin Uncoupling in Chemisorbed OCCO and CO 2: Two High-Energy Intermediates in Catalytic CO 2 Reduction

DOE PAGES

Hedstrom, Svante; dos Santos, Egon Campos; Liu, Chang; ...

2018-05-08

Here, the production of useful compounds via the electrochemical carbon dioxide reduction reaction (CO2RR) is a matter of intense research. Although the thermodynamics and kinetic barriers of CO2RR are reported in previous computational studies, the electronic structure details are often overlooked. We study two important CO2RR intermediates: ethylenedione (OCCO) and CO 2 covalently bound to cluster and slab models of the Cu(100) surface. Both molecules exhibit a near-unity negative charge as chemisorbed, but otherwise they behave quite differently, as explained by a spin-uncoupling perspective. OCCO adopts a high-spin, quartetlike geometry, allowing two covalent bonds to the surface with an averagemore » gross interaction energy of –1.82 eV/bond. The energy cost for electronically exciting OCCO– to the quartet state is 1.5 eV which is readily repaid via the formation of its two surface bonds. CO 2, conversely, retains a low-spin, doubletlike structure upon chemisorption, and its single unpaired electron forms a single covalent surface bond of –2.07 eV. The 5.0 eV excitation energy to the CO 2 – quartet state is prohibitively costly and cannot be compensated for by an additional surface bond.« less

Synthesis and characterization of heterobimetallic molybdenum and nickel complexes derived from polyfunctional disalicylaldehyde oxaloyldihydrazone

NASA Astrophysics Data System (ADS)

Kumar, Arvind; Borthakur, Rosmita; Koch, Angira; Chanu, Oinam B.; Choudhury, Sanjesh; Lemtur, Aka; Lal, Ram A.

2011-07-01

Heterobimetallic nickel and molybdenum complexes of the composition [Ni(L)MoO 2(A) 4]· nH 2O (A = H 2O (1), py (2), 2-pic (3), 3-pic (4), and 4-pic (5); n = 0, 2) and [Ni(L)(MoO 2)(BB) 2](BB = bpy (6) and (phen (7)) have been synthesized from the multidentate ligand disalicylaldehyde oxaloyldihydrazone (H 4L) in methanol. The composition of the complexes has been established based on data obtained from elemental analyses, thermoanalytical, mass spectral and molecular weight studies. The probable structures of the complexes have been discussed in the light of molar conductance, magnetic moment data and electronic, EPR and infrared spectral studies. In all of the complexes, the dihydrazone is present in enol form and coordinates to the metal centre as a tetrabasic hexadentate ligand. All of the complexes are normal paramagnetic to the extent of two unpaired electrons per nickel atom. The μeff values for the complexes lying in the region 2.87-3.07 B.M. are consistent with the octahedral stereochemistry of nickel(II) in the heterobimetallic complexes. The EPR and electronic spectral data also support the distorted octahedral stereochemistry of the nickel(II) centre. Both nickel and molybdenum have octahedral geometry in the complexes.

ESR, spectroscopic, and quantum-chemical studies on the electronic structures of complexes formed by Cu(I) with radicals (in Russian)

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

Gritsan, N.P.; Usov, O.M.; Shokhirev, N.V.

1986-07-01

The optical and ESR spectra have been examined for complexes of Cu(I) with various radicals, which contain various numbers of Cl/sup -/ ions in the central-atom coordination sphere. The spin-Hamiltonian parameters have been determined for all these radical complexes, and the observed ESR spectra have been compared with those calculated with allowance for second-order effects. The observed values for the isotropic and anisotropic components of the HFI constant from the central ion have been used to estimate the contributions from the 4s and 3d/sup 2//sub z/ orbitals of the copper ion to the unpaired-electron MO. Quantum-chemical calculations have been performedmore » by the INDO method on the electronic structures and geometries of complexes formed by CH/sub 2/OH with Cu(I) for various Cl/sup -/ contents in the coordination sphere. The radical is coordinated by the ..pi.. orbital on the carbon atom, and the stabilities of the radical complexes decrease as the number of Cl/sup -/ ions in the coordination sphere increases. A geometry close to planar for the CuCl/sub 4//sup 3 -/ fragment in a complex containing four Cl/sup -/ ions.« less

Sub-Doppler infrared spectroscopy of propargyl radical (H{sub 2}CCCH) in a slit supersonic expansion

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

Chang, Chih-Hsuan; Nesbitt, David J.

The acetylenic CH stretch mode (ν{sub 1}) of propargyl (H{sub 2}CCCH) radical has been studied at sub-Doppler resolution (∼60 MHz) via infrared laser absorption spectroscopy in a supersonic slit-jet discharge expansion, where low rotational temperatures (T{sub rot} = 13.5(4) K) and lack of spectral congestion permit improved determination of band origin and rotational constants for the excited state. For the lowest J states primarily populated in the slit jet cooled expansion, fine structure due to the unpaired electron spin is resolved completely, which permits accurate analysis of electron spin-rotation interactions in the vibrationally excited states (ε{sub aa} = − 518.1(1.8),more » ε{sub bb} = − 13.0(3), ε{sub cc} = − 1.8(3) MHz). In addition, hyperfine broadening in substantial excess of the sub-Doppler experimental linewidths is observed due to nuclear spin–electron spin contributions at the methylenic (—CH{sub 2}) and acetylenic (—CH) positions, which permits detailed modeling of the fine/hyperfine structure line contours. The results are consistent with a delocalized radical spin density extending over both methylenic and acetylenic C atoms, in excellent agreement with simple resonance structures as well as ab initio theoretical calculations.« less

The quality of paper-based versus electronic nursing care plan in Australian aged care homes: A documentation audit study.

PubMed

Wang, Ning; Yu, Ping; Hailey, David

2015-08-01

The nursing care plan plays an essential role in supporting care provision in Australian aged care. The implementation of electronic systems in aged care homes was anticipated to improve documentation quality. Standardized nursing terminologies, developed to improve communication and advance the nursing profession, are not required in aged care practice. The language used by nurses in the nursing care plan and the effect of the electronic system on documentation quality in residential aged care need to be investigated. To describe documentation practice for the nursing care plan in Australian residential aged care homes and to compare the quantity and quality of documentation in paper-based and electronic nursing care plans. A nursing documentation audit was conducted in seven residential aged care homes in Australia. One hundred and eleven paper-based and 194 electronic nursing care plans, conveniently selected, were reviewed. The quantity of documentation in a care plan was determined by the number of phrases describing a resident problem and the number of goals and interventions. The quality of documentation was measured using 16 relevant questions in an instrument developed for the study. There was a tendency to omit 'nursing problem' or 'nursing diagnosis' in the nursing process by changing these terms (used in the paper-based care plan) to 'observation' in the electronic version. The electronic nursing care plan documented more signs and symptoms of resident problems and evaluation of care than the paper-based format (48.30 vs. 47.34 out of 60, P<0.01), but had a lower total mean quality score. The electronic care plan contained fewer problem or diagnosis statements, contributing factors and resident outcomes than the paper-based system (P<0.01). Both types of nursing care plan were weak in documenting measurable and concrete resident outcomes. The overall quality of documentation content for the nursing process was no better in the electronic system than in the paper-based system. Omission of the nursing problem or diagnosis from the nursing process may reflect a range of factors behind the practice that need to be understood. Further work is also needed on qualitative aspects of the nurse care plan, nurses' attitudes towards standardized terminologies and the effect of different documentation practice on care quality and resident outcomes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Surgical electronic logbook: A step forward.

PubMed

Gómez Díaz, Carlos Javier; Luna Aufroy, Alexis; Rebasa Cladera, Pere; Serra Pla, Sheila; Jurado Ruiz, Cristina; Mora López, Laura; Serra Aracil, Xavier; Navarro Soto, Salvador

2015-12-01

The surgical electronic logbook (surgical e-logbook) aims to: simplify registration of the training activities of surgical residents, and to obtain reliable and detailed reports about these activities for resident evaluation. The surgical e-logbook is a unique and shared database. Residents prospectively record their activities in 3 areas: surgical, scientific and teaching. We can access activity reports that are constantly updated. Study period using the surgical e-logbook: Between June 2011 and May 2013. Number of surgeries reported: 4,255. Number of surgical procedures reported: 11,907. Number of surgeries per resident per year reported: 250. Number of surgical procedures per resident per year reported: 700. Surgical activity as a primary surgeon during the first year of residency is primarily in emergency surgery (68,01%) and by laparotomy (97,73%), while during the fifth year of residency 51,27% is performed in elective surgery and laparoscopy is used in 23,10% of cases. During this period, residents participated in a total of 11 scientific publications, 75 conference presentations and 69 continuing education activities. The surgical e-logbook is a useful tool that simplifies the recording and analysis of data about surgical and scientific activities of the residents. It is a step forward in the evaluation of the training of surgical residents, however, is only an intermediate step towards the development of a larger Spanish registry. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Unfolding and Targeting Thermodynamics of a DNA Intramolecular Complex with Joined Triplex-Duplex Domains.

PubMed

Johnson, Sarah E; Reiling-Steffensmeier, Calliste; Lee, Hui-Ting; Marky, Luis A

2018-01-25

Our laboratory is interested in developing methods that can be used for the control of gene expression. In this work, we are investigating the reaction of an intramolecular complex containing a triplex-duplex junction with partially complementary strands. We used a combination of isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), and spectroscopy techniques to determine standard thermodynamic profiles for these targeting reactions. Specifically, we have designed single strands to target one loop (CTTTC) or two loops (CTTTC and GCAA) of this complex. Both reactions yielded exothermic enthalpies of -66.3 and -82.8 kcal/mol by ITC, in excellent agreement with the reaction enthalpies of -72.7 and -88.7 kcal/mol, respectively, obtained from DSC Hess cycles. The favorable heat contributions result from the formation of base-pair stacks involving mainly the unpaired bases of the loops. This shows that each complementary strand is able to invade and disrupt the secondary structure. The simultaneous targeting of two loops yielded a more favorable reaction free energy, by approximately -8 kcal/mol, which corresponds to the formation of roughly four base-pair stacks involving the unpaired bases of the 5'-GCAA loop. The main conclusion is that the targeting of loops with a large number of unpaired bases results in a more favorable reaction free energy.

Pre-exposure to wheel running disrupts taste aversion conditioning.

PubMed

Salvy, Sarah-Jeanne; Pierce, W David; Heth, Donald C; Russell, James C

2002-05-01

When rats are given access to a running wheel after drinking a flavored solution, they subsequently drink less of that flavor solution. It has been suggested that running produces a conditioned taste aversion (CTA). This study explored whether CTA is eliminated by prior exposure to wheel running [i.e., unconditioned stimulus (UCS) pre-exposure effect]. The rats in the experimental group (UW) were allowed to wheel run for 1 h daily for seven consecutive days of pre-exposure. Rats in the two other groups had either access to locked wheels (LW group) or were maintained in their home cages (HC group) during the pre-exposure days. All rats were then exposed to four paired and four unpaired trials using a "ABBAABBA" design. Conditioning trials were composed of one flavored liquid followed by 60-min access to wheel running. For the unpaired trials, rats received a different flavor not followed by the opportunity to run. All rats were then initially tested for water consumption followed by tests of the two flavors (paired or unpaired) in a counterbalanced design. Rats in the UW group show no CTA to the liquid paired with wheel running, whereas LW and HC groups developed CTA. These results indicate that pre-exposure to wheel running (i.e., the UCS), eliminates subsequent CTA.

The effects of preceding lead-alone and lag-alone click trains on the buildup of echo suppression.

PubMed

Bishop, Christopher W; Yadav, Deepak; London, Sam; Miller, Lee M

2014-08-01

Spatial perception in echoic environments is influenced by recent acoustic history. For instance, echo suppression becomes more effective or "builds up" with repeated exposure to echoes having a consistent acoustic relationship to a temporally leading sound. Four experiments were conducted to investigate how buildup is affected by prior exposure to unpaired lead-alone or lag-alone click trains. Unpaired trains preceded lead-lag click trains designed to evoke and assay buildup. Listeners reported how many sounds they heard from the echo hemifield during the lead-lag trains. Stimuli were presented in free field (experiments 1 and 4) or dichotically through earphones (experiments 2 and 3). In experiment 1, listeners reported more echoes following a lead-alone train compared to a period of silence. In contrast, listeners reported fewer echoes following a lag-alone train; similar results were observed with earphones. Interestingly, the effects of lag-alone click trains on buildup were qualitatively different when compared to a no-conditioner trial type in experiment 4. Finally, experiment 3 demonstrated that the effects of preceding click trains on buildup cannot be explained by a change in counting strategy or perceived click salience. Together, these findings demonstrate that echo suppression is affected by prior exposure to unpaired stimuli.

Proline Scanning Mutagenesis Reveals a Role for the Flap Endonuclease-1 Helical Cap in Substrate Unpairing*

PubMed Central

Patel, Nikesh; Exell, Jack C.; Jardine, Emma; Ombler, Ben; Finger, L. David; Ciani, Barbara; Grasby, Jane A.

2013-01-01

The prototypical 5′-nuclease, flap endonuclease-1 (FEN1), catalyzes the essential removal of single-stranded flaps during DNA replication and repair. FEN1 hydrolyzes a specific phosphodiester bond one nucleotide into double-stranded DNA. This specificity arises from double nucleotide unpairing that places the scissile phosphate diester on active site divalent metal ions. Also related to FEN1 specificity is the helical arch, through which 5′-flaps, but not continuous DNAs, can thread. The arch contains basic residues (Lys-93 and Arg-100 in human FEN1 (hFEN1)) that are conserved by all 5′-nucleases and a cap region only present in enzymes that process DNAs with 5′ termini. Proline mutations (L97P, L111P, L130P) were introduced into the hFEN1 helical arch. Each mutation was severely detrimental to reaction. However, all proteins were at least as stable as wild-type (WT) hFEN1 and bound substrate with comparable affinity. Moreover, all mutants produced complexes with 5′-biotinylated substrate that, when captured with streptavidin, were resistant to challenge with competitor DNA. Removal of both conserved basic residues (K93A/R100A) was no more detrimental to reaction than the single mutation R100A, but much less severe than L97P. The ability of protein-Ca2+ to rearrange 2-aminopurine-containing substrates was monitored by low energy CD. Although L97P and K93A/R100A retained the ability to unpair substrates, the cap mutants L111P and L130P did not. Taken together, these data challenge current assumptions related to 5′-nuclease family mechanism. Conserved basic amino acids are not required for double nucleotide unpairing and appear to act cooperatively, whereas the helical cap plays an unexpected role in hFEN1-substrate rearrangement. PMID:24126913

Hypertension is associated with greater heat exchange during exercise recovery in a hot environment

PubMed Central

Fonseca, S. F.; Teles, M. C.; Ribeiro, V. G. C.; Magalhães, F. C.; Mendonça, V. A.; Peixoto, M. F. D.; Leite, L. H. R.; Coimbra, C. C.; Lacerda, A. C. R.

2015-01-01

Individuals with systemic arterial hypertension have a higher risk of heat-related complications. Thus, the aim of this study was to examine the thermoregulatory responses of hypertensive subjects during recovery from moderate-intensity exercise performed in the heat. A total of eight essential hypertensive (H) and eight normotensive (N) male subjects (age=46.5±1.3 and 45.6±1.4 years, body mass index=25.8±0.8 and 25.6±0.6 kg/m2, mean arterial pressure=98.0±2.8 and 86.0±2.3 mmHg, respectively) rested for 30 min, performed 1 h of treadmill exercise at 50% of maximal oxygen consumption, and rested for 1 h after exercise in an environmental chamber at 38°C and 60% relative humidity. Skin and core temperatures were measured to calculate heat exchange parameters. Mean arterial pressure was higher in the hypertensive than in the normotensive subjects throughout the experiment (P<0.05, unpaired t-test). The hypertensive subjects stored less heat (H=-24.23±3.99 W·m−2 vs N=-13.63±2.24 W·m−2, P=0.03, unpaired t-test), experienced greater variations in body temperature (H=-0.62±0.05°C vsN=-0.35±0.12°C, P=0.03, unpaired t-test), and had more evaporated sweat (H=-106.1±4.59 W·m−2 vs N=-91.15±3.24 W·m−2, P=0.01, unpaired t-test) than the normotensive subjects during the period of recovery from exercise. In conclusion, essential hypertensive subjects showed greater sweat evaporation and increased heat dissipation and body cooling relative to normotensive subjects during recovery from moderate-intensity exercise performed in hot conditions. PMID:26517335

Comparative neuroanatomy suggests repeated reduction of neuroarchitectural complexity in Annelida

PubMed Central

2010-01-01

Background Paired mushroom bodies, an unpaired central complex, and bilaterally arranged clusters of olfactory glomeruli are among the most distinctive components of arthropod neuroarchitecture. Mushroom body neuropils, unpaired midline neuropils, and olfactory glomeruli also occur in the brains of some polychaete annelids, showing varying degrees of morphological similarity to their arthropod counterparts. Attempts to elucidate the evolutionary origin of these neuropils and to deduce an ancestral ground pattern of annelid cerebral complexity are impeded by the incomplete knowledge of annelid phylogeny and by a lack of comparative neuroanatomical data for this group. The present account aims to provide new morphological data for a broad range of annelid taxa in order to trace the occurrence and variability of higher brain centers in segmented worms. Results Immunohistochemically stained preparations provide comparative neuroanatomical data for representatives from 22 annelid species. The most prominent neuropil structures to be encountered in the annelid brain are the paired mushroom bodies that occur in a number of polychaete taxa. Mushroom bodies can in some cases be demonstrated to be closely associated with clusters of spheroid neuropils reminiscent of arthropod olfactory glomeruli. Less distinctive subcompartments of the annelid brain are unpaired midline neuropils that bear a remote resemblance to similar components in the arthropod brain. The occurrence of higher brain centers such as mushroom bodies, olfactory glomeruli, and unpaired midline neuropils seems to be restricted to errant polychaetes. Conclusions The implications of an assumed homology between annelid and arthropod mushroom bodies are discussed in light of the 'new animal phylogeny'. It is concluded that the apparent homology of mushroom bodies in distantly related groups has to be interpreted as a plesiomorphy, pointing towards a considerably complex neuroarchitecture inherited from the last common ancestor, Urbilateria. Within the annelid radiation, the lack of mushroom bodies in certain groups is explained by widespread secondary reductions owing to selective pressures unfavorable for the differentiation of elaborate brains. Evolutionary pathways of mushroom body neuropils in errant polychaetes remain enigmatic. PMID:20441583

Initial review of Electronic Residency Application Service charts by orthopaedic residency faculty members. Does applicant gender matter?

PubMed

Scherl, S A; Lively, N; Simon, M A

2001-01-01

Orthopaedic surgery is a male-dominated field. As of 1998, women accounted for 42% of medical school graduates, yet only 6.9% of the total number of orthopaedic residents were female. The purpose of our study was to determine whether the Electronic Residency Application Service charts of female candidates for orthopaedic residencies are ranked lower by faculty reviewers than are those of male candidates with similar qualifications. After we obtained permission from the applicants, the Electronic Residency Application Service applications submitted by ninety male and ten female candidates for admission to a university orthopaedic residency program for the 1998 National Residency Matching Program were randomly divided into ten groups, consisting of the charts of nine male candidates and one female candidate. Each chart from a female candidate was altered into a "male" version, in which all names and personal pronouns were changed but which was otherwise identical to the original female version. Therefore, each group of ten charts existed as a paired set: one containing the true female chart and one, the altered "male" chart. The paired sets acted as their own control. One hundred and twenty-one faculty reviewers from fourteen orthopaedic residency programs around the United States each reviewed either the "male" or the female version of one set, without knowledge of the goals of the study, and ranked the ten charts in the order in which they would like to have the candidates as residents in their own programs. Each version of the sets was reviewed by at least five separate reviewers. Reviewers at a given institution were randomized to review different sets, so that there was no overlap among them. The rankings of the female-"male" pairs were compared with use of a standard paired t test. No significant difference was detected in the rankings of the female and "male" charts (p = 0.5). The mean difference in rankings was -0.33, with a 95% confidence interval ranging from -1.41 (favoring females) to 0.74 (favoring "males"). The low percentage of female residents is not due to bias against female applicants in the initial chart-review phase of the orthopaedic residency selection process. It is possible that bias is introduced in other stages of the selection process, such as the interview.

Does clinical exposure matter? Pilot assessment of patient visits in an urban family medicine residency program.

PubMed

Iglar, Karl; Murdoch, Stuart; Meaney, Christopher; Krueger, Paul

2018-01-01

To determine the number of patient visits, patient demographic information, and diagnoses in an urban ambulatory care setting in a family medicine residency program, and assess the correlation between the number of patient visits and residents' in-training examination (ITE) scores. Retrospective analysis of data from resident practice profiles, electronic medical records, and residents' final ITE scores. Family medicine teaching unit in a community hospital in Barrie, Ont. Practice profile data were from family medicine residents enrolled in the program from July 1, 2013, to June 30, 2014, and electronic medical record and ITE data were from those enrolled in the program from July 1, 2010, to June 30, 2015. Number of patient visits, patient characteristics (eg, sex, age), priority topics addressed in clinic, resident characteristics (eg, age, sex, level of residency), and residents' final ITE scores. Between July 1, 2013, and June 30, 2014, there were 11 115 patient visits. First-year residents had a mean of 5.48 patient visits per clinic, and second-year residents had a mean of 5.98 patient visits per clinic. A Pearson correlation coefficient of 0.68 was found to exist between the number of patients seen and the final ITE scores, with a 10.5% difference in mean score between residents who had 1251 or more visits and those who had 1150 or fewer visits. Three diagnoses (ie, epistaxis, meningitis, and neck pain) deemed important for Certification by the College of Family Physicians of Canada were not seen by any of the residents in clinic. There is a moderate correlation between the number of patients seen by residents in ambulatory care and ITE scores in family medicine. It is important to assess patients' demographic information and diagnoses made in resident practices to ensure an adequate clinical experience. Copyright© the College of Family Physicians of Canada.

Management of simulated maternal cardiac arrest by residents: didactic teaching versus electronic learning.

PubMed

Hards, Andrea; Davies, Sharon; Salman, Aliya; Erik-Soussi, Magda; Balki, Mrinalini

2012-09-01

Successful resuscitation of a pregnant woman undergoing cardiac arrest and survival of the fetus require prompt, high-quality cardiopulmonary resuscitation. The objective of this observational study was to assess management of maternal cardiac arrest by anesthesia residents using high-fidelity simulation and compare subsequent performance following either didactic teaching or electronic learning (e-learning). Twenty anesthesia residents were randomized to receive either didactic teaching (Didactic group, n = 10) or e-learning (Electronic group, n = 10) on maternal cardiac arrest. Baseline management skills were tested using high-fidelity simulation, with repeat simulation testing one month after their teaching intervention. The time from cardiac arrest to start of perimortem Cesarean delivery (PMCD) was measured, and the technical and nontechnical skills scores between the two teaching groups were compared. The median [interquartile range] time to PMCD decreased after teaching, from 4.5 min [3.4 to 5.1 min] to 3.5 min [2.5 to 4.0 min] (P = 0.03), although the change within each group was not statistically significant (Didactic group 4.9 to 3.8 min, P = 0.2; Electronic group 3.9 to 2.5 min, P = 0.07; Didactic group vs Electronic group, P = 1.0). Even after teaching, only 65% of participants started PMCD within four minutes. Technical and nontechnical skills scores improved after teaching in both groups, and there were no differences between the groups. There are gaps in the knowledge and implementation of resuscitation protocols and the recommended modifications for pregnancy among residents. Teaching can improve performance during management of maternal cardiac arrest. Electronic learning and didactic teaching offer similar benefits.

Floquet topological polaritons in semiconductor microcavities

NASA Astrophysics Data System (ADS)

Ge, R.; Broer, W.; Liew, T. C. H.

2018-05-01

We propose and model Floquet topological polaritons in semiconductor microcavities, using the interference of frequency-detuned coherent fields to provide a time-periodic potential. For arbitrarily weak field strength, where the Floquet frequency is larger than the relevant bandwidth of the system, a Chern insulator is obtained. As the field strength is increased, a topological phase transition is observed with an unpaired Dirac cone proclaiming the anomalous Floquet topological insulator. As the relevant bandwidth increases even further, an exotic Chern insulator with flatband is observed with unpaired Dirac cone at the second critical point. Considering the polariton spin degree of freedom, we find that the choice of field polarization allows oppositely polarized polaritons to either copropagate or counterpropagate in chiral edge states.

Inhibition of Escherichia coli viability by external guide sequences complementary to two essential genes

PubMed Central

McKinney, Jeffrey; Guerrier-Takada, Cecilia; Wesolowski, Donna; Altman, Sidney

2001-01-01

Narrow spectrum antimicrobial activity has been designed to reduce the expression of two essential genes, one coding for the protein subunit of RNase P (C5 protein) and one for gyrase (gyrase A). In both cases, external guide sequences (EGS) have been designed to complex with either mRNA. Using the EGS technology, the level of microbial viability is reduced to less than 10% of the wild-type strain. The EGSs are additive when used together and depend on the number of nucleotides paired when attacking gyrase A mRNA. In the case of gyrase A, three nucleotides unpaired out of a 15-mer EGS still favor complete inhibition by the EGS but five unpaired nucleotides do not. PMID:11381134

Exploring the Association Between Electronic Health Record Use and Burnout Among Psychiatry Residents and Faculty: a Pilot Survey Study.

PubMed

Domaney, Nicholas M; Torous, John; Greenberg, William E

2018-05-21

Burnout is a phenomenon with profound negative effects on the US healthcare system. Little is known about the relationship between time spent working on electronic health record (EHR) and burnout among psychiatry residents. The purpose of this study is to generate preliminary data on EHR use and burnout among psychiatry residents and faculty. In August 2017, psychiatry residents and faculty at an academic medical center were given the Maslach Burnout Inventory (MBI), a standardized measurement tool for burnout, and a survey of factors related to EHR use and potential risk factors for burnout. MBI data along with selected burnout risk and protective factors were analyzed with R Studio software. Responses were obtained from 40 psychiatry residents (73%) and 12 clinical faculty members (40%). Residents reported 22 h per week using EHR on average. Mean score of residents surveyed in postgraduate year (PGY)-1-4 met criteria for high emotional exhaustion associated with burnout. The magnitude of correlation between EHR use and emotional exhaustion was stronger than for other burnout factors including sleep, exercise, and clinical service. Psychiatry residents show signs of high emotional exhaustion, which is associated with burnout. Results demonstrate a strong positive correlation between EHR use and resident burnout. Time spent on EHR use may be an area of importance for psychiatry program directors and other psychiatric educators to consider when seeking to minimize burnout and promote wellness.

Assessing the impact of innovative training of family physicians for the patient-centered medical home.

PubMed

Carney, Patricia A; Eiff, M Patrice; Saultz, John W; Lindbloom, Erik; Waller, Elaine; Jones, Samuel; Osborn, Jamie; Green, Larry

2012-03-01

New approaches to enhance access in primary care necessitate change in the model for residency education. To describe instrument design, development and testing, and data collection strategies for residency programs, continuity clinics, residents, and program graduates participating in the Preparing the Personal Physician for Practice (P(4)) project. We developed and pilot-tested surveys to assess demographic characteristics of residents, clinical and operational features of the continuity clinics and educational programs, and attitudes about and implementation status of Patient Centered Medical Home (PCMH) characteristics. Surveys were administered annually to P(4) residency programs since the project started in 2007. Descriptive statistics were used to profile data from the P(4) baseline year. Most P(4) residents were non-Hispanic white women (60.7%), married or partnered, attended medical school in the United States and were the first physicians in their families to attend medical school. Nearly 85% of residency continuity clinics were family health centers, and about 8% were federally qualified health centers. The most likely PCMH features in continuity clinics were having an electronic health record and having fully secure remote access available; both of which were found in more than 50% of continuity clinics. Approximately one-half of continuity clinics used the electronic health record for safety projects, and nearly 60% used it for quality-improvement projects. We created a collaborative evaluation model in all 14 P(4) residencies. Successful implementation of new surveys revealed important baseline features of residencies and residents that are pertinent to studying the effects of new training models for the PCMH.

Kramers degeneracy and relaxation in vanadium, niobium and tantalum clusters

NASA Astrophysics Data System (ADS)

Diaz-Bachs, A.; Katsnelson, M. I.; Kirilyuk, A.

2018-04-01

In this work we use magnetic deflection of V, Nb, and Ta atomic clusters to measure their magnetic moments. While only a few of the clusters show weak magnetism, all odd-numbered clusters deflect due to the presence of a single unpaired electron. Surprisingly, for the majority of V and Nb clusters an atomic-like behavior is found, which is a direct indication of the absence of spin–lattice interaction. This is in agreement with Kramers degeneracy theorem for systems with a half-integer spin. This purely quantum phenomenon is surprisingly observed for large systems of more than 20 atoms, and also indicates various quantum relaxation processes, via Raman two-phonon and Orbach high-spin mechanisms. In heavier, Ta clusters, the relaxation is always present, probably due to larger masses and thus lower phonon energies, as well as increased spin–orbit coupling.

Impact of vanadium ions in barium borate glass

NASA Astrophysics Data System (ADS)

Abdelghany, A. M.; Hammad, Ahmed H.

2015-02-01

Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.

Dynamics of oxygen species on reduced TiO2 (110) rutile

NASA Astrophysics Data System (ADS)

Wang, Yun; Pillay, Devina; Hwang, Gyeong S.

2004-11-01

Using density functional theory calculations, we have investigated the adsorption and diffusion of oxygen species on the reduced TiO2(110) surface. We have found that molecular O2 strongly binds not only to O vacancies, but also to Ti(5c) neighbors, due to delocalization of unpaired electrons arising from removal of neutral bridging oxygen. Our results show that molecular O2 can jump across an oxygen vacancy and diffuse along a Ti(5c) row with moderate barriers. On the other hand, atomic O diffusion along a Ti(5c) row is rather unlikely at low temperatures (<300K) , because of the relatively higher probability of O-O formation from interaction with an adjacent bridging O(2c) atom. Based on our calculation results, we discuss the diffusion and healing of O vacancies associated with O2 adsorption.

Highly durable organic electrode for sodium-ion batteries via a stabilized α-C radical intermediate

NASA Astrophysics Data System (ADS)

Wu, Shaofei; Wang, Wenxi; Li, Minchan; Cao, Lujie; Lyu, Fucong; Yang, Mingyang; Wang, Zhenyu; Shi, Yang; Nan, Bo; Yu, Sicen; Sun, Zhifang; Liu, Yao; Lu, Zhouguang

2016-11-01

It is a challenge to prepare organic electrodes for sodium-ion batteries with long cycle life and high capacity. The highly reactive radical intermediates generated during the sodiation/desodiation process could be a critical issue because of undesired side reactions. Here we present durable electrodes with a stabilized α-C radical intermediate. Through the resonance effect as well as steric effects, the excessive reactivity of the unpaired electron is successfully suppressed, thus developing an electrode with stable cycling for over 2,000 cycles with 96.8% capacity retention. In addition, the α-radical demonstrates reversible transformation between three states: C=C α-C.radical and α-C- anion. Such transformation provides additional Na+ storage equal to more than 0.83 Na+ insertion per α-C radical for the electrodes. The strategy of intermediate radical stabilization could be enlightening in the design of organic electrodes with enhanced cycling life and energy storage capability.

Electrical conductivity and magnetic susceptibility of rutile type CrVNbO/sub 6/, FeVNbO/sub 6/ and NiV/sub 2/Nb/sub 2/O/sub 10/

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

Greenblatt, M.; McCarroll, W.H.; Nair, K.R.

1984-06-01

Electric conductivity (77-300K) and magnetic susceptibility (4.2-300K) of rutile type polycrystalline samples of CrVNbO/sub 6/, FeVNbO/sub 6/ and NiV/sub 2/Nb/sub 2/O/sub 10/ are reported. All three compounds are n-type semiconductors with room-temperature resistivities of the order of 10/sup 2/-10/sup 3/ ohm-cm. CrVNbO/sub 6/ shows ferromagnetic coupling in the high-temperature region and orders antiferromagnetically below 10K. FeVNbO/sub 6/ transforms to a spin glass state below 20K. NiV/sub 2/Nb/sub 2/O/sub 10/ shows evidence of weak antiferromagnetic interactions. The transport properties of the compounds are discussed in terms of structural properties and unpaired d electrons present on the respective transition metal ions.

Improved solar light stimulated charge separation of g-C3N4 through self-altering acidic treatment

NASA Astrophysics Data System (ADS)

Leong, Kah Hon; Lim, Ping Feng; Sim, Lan Ching; Punia, Varun; Pichiah, Saravanan

2018-02-01

Herein, we report the use of acid treatment to treat g-C3N4 nanostructured by a direct and facile synthesis route. The adopted treatment enhanced photoactivity of g-C3N4 and reflected in the removal of recalcitrant organic pollutant, Bisphenol A under direct sunlight. A complete removal of Bisphenol A was attained in a short duration (225 min) as compared to pure g-C3N4. The analysis clearly substantiated the robustness of acid exfoliation that promoted a blue shift, extended the conjugated length of its respective conduction and valance band. It also drastically prolonged the recombination rate of charge carriers, by producing excess of unpaired electrons in the conduction band for active radicals' generation. Thus, this new findings could offer a new sight of self-alteration in improving the photoactivity of complex organic pollutants for sustainable environmental remediation.

The cluster Ir4 and its interaction with a hydrogen impurity. A density functional study.

PubMed

Bussai, Chuenchit; Krüger, Sven; Vayssilov, Georgi N; Rösch, Notker

2005-07-07

To contribute to the understanding of how iridium particles act as catalysts for hydrogenation and dehydrogenation of hydrocarbons, we have determined structures and binding energies of various isomers of Ir(4) as well as HIr(4) on the basis of relativistic density functional theory. The most stable isomer of Ir(4) showed a square planar structure with eight unpaired electrons. The tetrahedral structure, experimentally suggested for supported species, was calculated 49 kJ mol(-1) less stable. Hydrogen coordinates preferentially to a single Ir center of the planar cluster with a binding energy of up to 88 kJ mol(-1) with respect to the atom in the H(2) molecule. Terminal interaction of hydrogen with an Ir(4) tetrahedron causes the cluster to open to a butterfly structure. We calculated terminal binding of hydrogen at different Ir(4) isomers to be more stable than bridge coordination, at variance with earlier studies.

Proton, muon and ¹³C hyperfine coupling constants of C₆₀X and C₇₀X (X = H, Mu).

PubMed

Brodovitch, Jean-Claude; Addison-Jones, Brenda; Ghandi, Khashayar; McKenzie, Iain; Percival, Paul W

2015-01-21

The reaction of H atoms with fullerene C70 has been investigated by identifying the radical products formed by addition of the atom muonium (Mu) to the fullerene in solution. Four of the five possible radical isomers of C70Mu were detected by avoided level-crossing resonance (μLCR) spectroscopy, using a dilute solution of enriched (13)C70 in decalin. DFT calculations were used to predict muon and (13)C isotropic hyperfine constants as an aid to assigning the observed μLCR signals. Computational methods were benchmarked against previously published experimental data for (13)C60Mu in solution. Analysis of the μLCR spectrum resulted in the first experimental determination of (13)C hyperfine constants in either C70Mu or C70H. The large number of values confirms predictions that the four radical isomers have extended distributions of unpaired electron spin.

Copper(II) complexes of tridentate N, N, N', N″, N″-pentamethyldiethylenetriamine: Superoxide dismutase and inhibitory activity against bacteria and fungi

NASA Astrophysics Data System (ADS)

Patel, R. N.; Singh, Nripendra; Gundla, V. L. N.; Chauhan, U. K.

2007-03-01

A series of ternary copper(II) complexes containing same coordination sphere but difference in the counter ions, viz., [Cu(PMDT)(OAc)]PF 6(1); [Cu(PMDT)(OAc)]ClO 4(2); [Cu(PMDT)(OAc)]BF 4(3) and [Cu(PMDT)(OAc)]BPh 4(4) where PMDT = N, N, N', N″, N″-pentamethyldiethylenetriamine, OAc = Acetate ion were synthesized and characterized by means of spectroscopic, magnetic and cyclic voltammetric measurements. In frozen solution e.p.r. spectra, an interesting relation g|| > g⊥ has been observed which is a typical of the axially symmetric d 9 Cu II ( SCu = 1/2) having an unpaired electron in a d orbital. Single crystal X-ray analysis of (1) has revealed the presence of distorted square planar geometry. The influence of the counter ion on the complexes has been examined by performing some biological experiments like superoxide dismutase and anti-microbial activity.

Investigation of the electronic ground states for a reduced pyridine(diimine) uranium series: evidence for a ligand tetraanion stabilized by a uranium dimer.

PubMed

Anderson, Nickolas H; Odoh, Samuel O; Williams, Ursula J; Lewis, Andrew J; Wagner, Gregory L; Lezama Pacheco, Juan; Kozimor, Stosh A; Gagliardi, Laura; Schelter, Eric J; Bart, Suzanne C

2015-04-15

The electronic structures of a series of highly reduced uranium complexes bearing the redox-active pyridine(diimine) ligand, (Mes)PDI(Me) ((Mes)PDI(Me) = 2,6-(2,4,6-Me3-C6H2-N═CMe)2C5H3N) have been investigated. The complexes, ((Mes)PDI(Me))UI3(THF) (1), ((Mes)PDI(Me))UI2(THF)2 (2), [((Mes)PDI(Me))UI]2 (3), and [((Mes)PDI(Me))U(THF)]2 (4), were examined using electronic and X-ray absorption spectroscopies, magnetometry, and computational analyses. Taken together, these studies suggest that all members of the series contain uranium(IV) centers with 5f (2) configurations and reduced ligand frameworks, specifically [(Mes)PDI(Me)](•/-), [(Mes)PDI(Me)](2-), [(Mes)PDI(Me)](3-) and [(Mes)PDI(Me)](4-), respectively. In the cases of 2, 3, and 4 no unpaired spin density was found on the ligands, indicating a singlet diradical ligand in monomeric 2 and ligand electron spin-pairing through dimerization in 3 and 4. Interaction energies, representing enthalpies of dimerization, of -116.0 and -144.4 kcal mol(-1) were calculated using DFT for the monomers of 3 and 4, respectively, showing there is a large stabilization gained by dimerization through uranium-arene bonds. Highlighted in these studies is compound 4, bearing a previously unobserved pyridine(diimine) tetraanion, that was uniquely stabilized by backbonding between uranium cations and the η(5)-pyridyl ring.

Synthesis, electronic and ESR spectral studies on copper(II) nitrate complexes with some acylhydrazines and hydrazones.

PubMed

Singh, Vinod P

2008-11-01

This paper describes the preparation of [Cu(bh)2(H2O)2](NO3)2], [Cu(ibh)2(NO3)2], [Cu(ibh)2(H2O)2](NO3)2 and [Cu(iinh)2(NO3)2] (bh = benzoyl hydrazine (C6H5CONHNH2); ibh = isonicotinoyl hydrazine (NC5H4CONHNH2); ibh = isopropanone benzoyl hydrazone (C6H5CONHN=C(CH3)2; iinh = isopropanone isonicotinoyl hydrazone (NC5H4CONHN=C(CH3)2). These copper(II) complexes are characterized by elemental analyses, molar conductances, dehydration studies, ESR, IR and electronic spectral studies. The electronic and ESR spectra indicate that each complex exhibits a six-coordinate tetragonally distorted octahedral geometry in the solid state and in DMSO solution. The ESR spectra of most of the complexes are typically isotropic type at room temperature (300 K) in solid state as well as in DMSO solution. However, all the complexes exhibit invariably axial signals at 77 K in DMSO solution. The trend g(||) > g(perpendicular) > g(e,) observed in all the complexes suggests the presence of an unpaired electron in the d x2-y2 orbital of the Cu(II). The bh and inh ligands bond to Cu(II) through the >C=O and -NH2 groups whereas, ibh and iinh bond through >C=O and >C=N- groups. The IR spectra of bh and ibh complexes also show H-O-H stretching and bending modes of coordinated water.

Neurology didactic curricula for psychiatry residents: a review of the literature and a survey of program directors.

PubMed

Reardon, Claudia L; Walaszek, Art

2012-03-01

Minimal literature exists on neurology didactic instruction offered to psychiatry residents, and there is no model neurology didactic curriculum offered for psychiatry residency programs. The authors sought to describe the current state of neurology didactic training in psychiatry residencies. The authors electronically surveyed 172 directors of U.S. psychiatric residency training programs to examine the types and extent of neurology didactic instruction offered to their residents. Fifty-seven program directors (33%) responded. The majority of these psychiatry residency programs offer neurology didactic instruction to their residents, as provided by both neurology and psychiatry faculty, in a number of different settings and covering many topics. However, room for improvement likely remains. The authors hope this report will guide psychiatry residencies in optimizing their neurology didactic curricula. Further research should explore tools for assessing resident knowledge in neurology and measure the effectiveness of neurology curricula in increasing knowledge and improving clinical outcomes.

Effects of systemic glutamatergic manipulations on conditioned eyeblink responses and hyperarousal in a rabbit model of post-traumatic stress disorder.

PubMed

Burhans, Lauren B; Smith-Bell, Carrie A; Schreurs, Bernard G

2017-10-01

Glutamatergic dysfunction is implicated in many neuropsychiatric conditions, including post-traumatic stress disorder (PTSD). Glutamate antagonists have shown some utility in treating PTSD symptoms, whereas glutamate agonists may facilitate cognitive behavioral therapy outcomes. We have developed an animal model of PTSD, based on conditioning of the rabbit's eyeblink response, that addresses two key features: conditioned responses (CRs) to cues associated with an aversive event and a form of conditioned hyperarousal referred to as conditioning-specific reflex modification (CRM). The optimal treatment to reduce both CRs and CRM is unpaired extinction. The goals of the study were to examine whether treatment with the N-methyl-D-aspartate glutamate receptor antagonist ketamine could reduce CRs and CRM, and whether the N-methyl-D-aspartate agonist D-cycloserine combined with unpaired extinction treatment could enhance the extinction of both. Administration of a single dose of subanesthetic ketamine had no significant immediate or delayed effect on CRs or CRM. Combining D-cycloserine with a single day of unpaired extinction facilitated extinction of CRs in the short term while having no impact on CRM. These results caution that treatments may improve one aspect of the PTSD symptomology while having no significant effects on other symptoms, stressing the importance of a multiple-treatment approach to PTSD and of animal models that address multiple symptoms.

Localised JAK/STAT Pathway Activation Is Required for Drosophila Wing Hinge Development

PubMed Central

Johnstone, Kirsty; Wells, Richard E.; Strutt, David; Zeidler, Martin P.

2013-01-01

Extensive morphogenetic remodelling takes place during metamorphosis from a larval to an adult insect body plan. These changes are particularly intricate in the generation of the dipteran wing hinge, a complex structure that is derived from an apparently simple region of the wing imaginal disc. Using the characterisation of original outstretched alleles of the unpaired locus as a starting point, we demonstrate the role of JAK/STAT pathway signalling in the process of wing hinge development. We show that differences in JAK/STAT signalling within the proximal most of three lateral folds present in the wing imaginal disc is required for fold morphology and the subsequent differentiation of the first and second auxiliary sclerites as well as the posterior notal wing process. Changes in these domains are consistent with the established fate map of the wing disc. We show that outstretched wing posture phenotypes arise from the loss of a region of Unpaired expression in the proximal wing fold and demonstrate that this results in a decrease in JAK/STAT pathway activity. Finally we show that reduction of JAK/STAT pathway activity within the proximal wing fold is sufficient to phenocopy the outstretched phenotype. Taken together, we suggest that localised Unpaired expression and hence JAK/STAT pathway activity, is required for the morphogenesis of the adult wing hinge, providing new insights into the link between signal transduction pathways, patterning and development. PMID:23741461

Short double-stranded RNAs with an overhanging 5' ppp-nucleotide, as found in arenavirus genomes, act as RIG-I decoys.

PubMed

Marq, Jean-Baptiste; Hausmann, Stéphane; Veillard, Nicolas; Kolakofsky, Daniel; Garcin, Dominique

2011-02-25

Arenavirus RNA genomes are initiated by a "prime and realign" mechanism, such that the initiating GTP is found as a single unpaired (overhanging) nucleotide when the complementary genome ends anneal to form double-stranded (ds) RNA panhandle structures. dsRNAs modeled on these structures do not induce interferon (IFN), as opposed to blunt-ended (5' ppp)dsRNA. This study examines whether these viral structures can also act as decoys, by trapping RIG-I in inactive dsRNA complexes. We examined the ability of various dsRNAs to activate the RIG-I ATPase (presumably a measure of helicase translocation on dsRNA) relative to their ability to induce IFN. We found that there is no simple relationship between these two properties, as if RIG-I can translocate on short dsRNAs without inducing IFN. Moreover, we found that (5' ppp)dsRNAs with a single unpaired 5' ppp-nucleotide can in fact competitively inhibit the ability of blunt-ended (5' ppp)dsRNAs to induce IFN when co-transfected into cells and that this inhibition is strongly dependent on the presence of the 5' ppp. In contrast, (5' ppp)dsRNAs with a single unpaired 5' ppp-nucleotide does not inhibit poly(I-C)-induced IFN activation, which is independent of the presence of a 5' ppp group.

Seasonal differences of corticosterone metabolite concentrations and parasite burden in northern bald ibis (Geronticus eremita): The role of affiliative interactions

PubMed Central

Wascher, Claudia A. F.; Loretto, Matthias-Claudio; Palme, Rupert; Stoewe, Mareike; Kotrschal, Kurt; Frigerio, Didone

2018-01-01

The reproductive season is energetically costly as revealed by elevated glucocorticoid concentrations, constrained immune functions and an increased risk of infections. Social allies and affiliative interactions may buffer physiological stress responses and thereby alleviate associated effects. In the present study, we investigated the seasonal differences of immune reactive corticosterone metabolite concentrations, endoparasite burden (nematode eggs and coccidian oocysts) and affiliative interactions in northern bald ibis (Geronticus eremita), a critically endangered bird. In total, 43 individually marked focal animals from a free-ranging colony were investigated. The analyses included a description of initiated and received affiliative interactions, pair bond status as well as seasonal patterns of hormone and endoparasite levels. During the reproductive season, droppings contained parasite eggs more often and corticosterone metabolite levels were higher as compared to the period after reproduction. The excretion rate of endoparasite products was lower in paired individuals than in unpaired ones, but paired animals exhibited higher corticosterone metabolite concentrations than unpaired individuals. Furthermore, paired individuals initiated affiliative behaviour more frequently than unpaired ones. This suggests that the reproductive season influences the excretion patterns of endoparasite products and corticosterone metabolites and that affiliative interactions between pair partners may positively affect endoparasite burden during periods of elevated glucocorticoid levels. Being embedded in a pair bond may have a positive impact on individual immune system and parasite resistance. PMID:29364951

Determination of mutated genes in the presence of wild-type DNA by using molecular beacons as probe

NASA Astrophysics Data System (ADS)

Zhang, Yonghua; Ai, Junjie; Gu, Qiaorong; Gao, Qiang; Qi, Honglan; Zhang, Chengxiao

2017-03-01

Low-abundance mutations in the presence of wild-type DNA can be determined using molecular beacon (MB) as probe. A MB is generally used as DNA probe because it can distinguish single-base mismatched target DNA from fully matched target DNA. However, the probe can not determine low-abundance mutations in the presence of wild-type DNA. In this study, this limitation is addressed by enhancing the stability of unpaired base-containing dsDNA with a hydrogen-bonding ligand, which was added after hybridization of the MB to the target DNA. The ligand formed hydrogen bonds with unpaired bases and stabilized the unpaired base-containing dsDNA if target DNA is mutated one. As a result, more MBs were opened by the mutant genes in the presence of the ligand and a further increase in the fluorescence intensity was obtained. By contrast, fluorescence intensity did not change if target DNA is wild-type one. Consequent increase in the fluorescence intensity of the MB was regarded as a signal derived from mutant genes. The proposed method was applied in synthetic template systems to determine point mutation in DNA obtained from PCR analysis. The method also allows rapid and simple discrimination of a signal if it is originated in the presence of mutant gene or alternatively by a lower concentration of wild gene.

Recovery of Pavlovian sign-tracking (autoshaping) following the discontinuation of inter-trial interval food in rats.

PubMed

Kearns, David N; Weiss, Stanley J

2007-07-01

In pigeons, Pavlovian autoshaped keypecking produced by keylight-food pairings has been eliminated by introducing food during periods between CS presentations (i.e., during the inter-trial intervals). Keypecking eliminated in this manner reappears when the inter-trial USs are discontinued even though the CS is no longer paired with US. The present experiment investigated whether this recovery of responding produced by discontinuing unpaired inter-trial US presentations could be extended to another species, rats, within a Pavlovian sign-tracking paradigm. Rats were initially trained on a procedure where insertion of one retractable lever (CS(+)) was followed, response independently, with food, while insertion of another lever (CS(-)) was not paired with food. Rats quickly came to contact the CS(+) lever at high rates, but contacted the CS(-) lever infrequently. In the next phase, CS(+) was no longer followed by food. Explicitly unpaired food was presented only during the inter-trial intervals when both levers were absent. This treatment essentially eliminated the sign-tracking response. In the final phase, the unpaired inter-trial food presentations were discontinued while both CSs continued to be presented without food. This produced a significant recovery of the sign-tracking elicited by the CS(+) lever, extending the species generality of the Pavlovian resurgence phenomenon that has previously only been reported in pigeons, to rats.

Recognition of DNA bulges by dinuclear iron(II) metallosupramolecular helicates.

PubMed

Malina, Jaroslav; Hannon, Michael J; Brabec, Viktor

2014-02-01

Bulged DNA structures are of general biological significance because of their important roles in a number of biochemical processes. Compounds capable of targeting bulged DNA sequences can be used as probes for studying their role in nucleic acid function, or could even have significant therapeutic potential. The interaction of [Fe(2)L(3)](4+) metallosupramolecular helicates (L = C(25)H(20)N(4)) with DNA duplexes containing bulges has been studied by measurement of the DNA melting temperature and gel electrophoresis. This study was aimed at exploring binding affinities of the helicates for DNA bulges of various sizes and nucleotide sequences. The studies reported herein reveal that both enantiomers of [Fe(2)L(3)](4+) bind to DNA bulges containing at least two unpaired nucleotides. In addition, these helicates show considerably enhanced affinity for duplexes containing unpaired pyrimidines in the bulge and/or pyrimidines flanking the bulge on both sides. We suggest that the bulge creates the structural motif, such as the triangular prismatic pocket formed by the unpaired bulge bases, to accommodate the [Fe(2)L(3)](4+) helicate molecule, and is probably responsible for the affinity for duplexes with a varying number of bulge bases. Our results reveal that DNA bulges represent another example of unusual DNA structures recognized by dinuclear iron(II) ([Fe(2)L(3)](4+)) supramolecular helicates. © 2013 FEBS.

Tuning magnetic exchange interactions in crystalline thin films of substituted Cobalt Phthalocyanine

NASA Astrophysics Data System (ADS)

Rawat, Naveen; Manning, Lane; Hua, Kim-Ngan; Headrick, Randall; Bishop, Michael; McGill, Stephen; Waterman, Rory; Furis, Madalina

Magnetic exchange interactions in diluted organometallic crystalline thin film alloys of Phthalocyanines (Pcs) made of a organo-soluble derivatives of Cobalt Pc and metal-free (H2Pc) molecule and is investigated. To this end, we synthesized a organosoluble CoPc and successfully employed a novel solution-based pen-writing deposition technique to fabricate long range ordered thin films of mixtures of different ratios ranging from 1:1 to 10:1 H2Pc:CoPc. Our previous magnetic circular dichroism (MCD) results on the parent CoPc crystalline thin films identified different electronic states mediating exchange interactions and indirect exchange interaction competing with superexchange interaction. This understanding of spin-dependent exchange interaction between delocalized π-electrons with unpaired d spins along with the excitonic delocalization character enabled the further tuning of these interactions by essentially varying the spatial distance between the spins. Furthermore, high magnetic field (B < 25 T) MCD and magneto-photoluminescence show evidence of spin-polarized band-edge excitons in the same materials. This work was possible due to support by the National Science Foundation, Division of Materials Research MRI, CAREER and EPM program Awards: DMR-0722451, DMR-0821268, DMR-1307017 and DMR-1056589, DMR-1229217.

Use of multi-coil parallel-gap resonators for co-registration EPR/NMR imaging

NASA Astrophysics Data System (ADS)

Kawada, Yuuki; Hirata, Hiroshi; Fujii, Hirodata

2007-01-01

This article reports experimental investigations on the use of RF resonators for continuous-wave electron paramagnetic resonance (cw-EPR) and proton nuclear magnetic resonance (NMR) imaging. We developed a composite resonator system with multi-coil parallel-gap resonators for co-registration EPR/NMR imaging. The resonance frequencies of each resonator were 21.8 MHz for NMR and 670 MHz for EPR. A smaller resonator (22 mm in diameter) for use in EPR was placed coaxially in a larger resonator (40 mm in diameter) for use in NMR. RF magnetic fields in the composite resonator system were visualized by measuring a homogeneous 4-hydroxy-2,2,6,6-tetramethyl-piperidinooxy (4-hydroxy-TEMPO) solution in a test tube. A phantom of five tubes containing distilled water and 4-hydroxy-TEMPO solution was also measured to demonstrate the potential usefulness of this composite resonator system in biomedical science. An image of unpaired electrons was obtained for 4-hydroxy-TEMPO in three tubes, and was successfully mapped on the proton image for five tubes. Technical problems in the implementation of a composite resonator system are discussed with regard to co-registration EPR/NMR imaging for animal experiments.

Structural investigations of vanadyl doped Nb2O5·K2O·B2O3 glasses

NASA Astrophysics Data System (ADS)

Anshu; Sanghi, S.; Agarwal, A.; Lather, M.; Bhatnagar, V.; Khasa, S.

2009-07-01

Pottasium nioborate glasses of composition xNb2O5·(30-x)K2O·69B2O3 containing 1 mol % of V2O5 were prepared by melt quench technique (1473K, 1h). The electron paramagnetic resonance spectra of VO2+ in these glasses have been recorded in X- band (v approx 9.14 GHz) at room temperature (RT). The spin Hamiltonian parameters, dipolar hyperfine coupling parameters, P and Fermi contact interaction parameter, K have been calculated. It is found that V4+ ions in these glasses exist as VO2+ in octahedral coordination with a tetragonal distortion. The tetragonality of V4+O6 complex decreases with increasing Nb2O5: K2O ratio and also there is an expansion of 3dXY orbit of unpaired electron in the vanadium ion. The study of IR transmission spectra over a range 400- 4000 cm-1 depicts the presence of both BO3 and BO4 structural units and Nb5+ ions are incorporated into the glass network as NbO6 octahedra, substituting BO4 groups.

Effect of WO3 on EPR, structure and electrical conductivity of vanadyl doped WO3·M2O·B2O3 (M=Li, Na) glasses

NASA Astrophysics Data System (ADS)

Sheoran, A.; Agarwal, A.; Sanghi, S.; Seth, V. P.; Gupta, S. K.; Arora, M.

2011-12-01

Glasses with composition xWO3·(30-x)M2O·70B2O3 (M=Li, Na; 0≤x≤15) doped with 2 mol% V2O5 have been prepared using the melt-quench technique. The electron paramagnetic resonance spectra have been recorded in X-band (ν≈9.14 GHz) at room temperature (RT). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter and Fermi contact interaction parameter have been calculated. It is observed that the resultant resonance spectra contain hyperfine structures (hfs) only due to V4+ ions, which exist as VO2+ ions in octahedral coordination with a tetragonal compression in the present glass system. The tetragonality increases with WO3:M2O ratio and also there is an expansion of 3dxy orbit of unpaired electron in the vanadium ion. The study of IR transmission spectra over a range 400-4000 cm-1 depicts the presence of WO6 group. The DC conductivity (σ) has been measured in the temperature range 423-623 K and is found to be predominantly ionic.

DFT and ENDOR Study of Bixin Radical Cations and Neutral Radicals on Silica-Alumina.

PubMed

Tay-Agbozo, Sefadzi S; Krzyaniak, Matthew D; Bowman, Michael K; Street, Shane; Kispert, Lowell D

2015-06-18

Bixin, a carotenoid found in annatto (Bixa orellana), is unique among natural carotenoids by being water-soluble. We stabilized free radicals from bixin on the surface of silica-alumina (Si-Al) and characterized them by pulsed electron-nuclear double resonance (ENDOR). DFT calculations of unpaired electron spin distribution for various bixin radicals predict the EPR hyperfine couplings. Least-square fitting of experimental ENDOR spectra by spectra calculated from DFT hyperfine couplings characterized the radicals trapped on Si-Al. DFT predicts that the trans bixin radical cation is more stable than the cis bixin radical cation by 1.26 kcal/mol. This small energy difference is consistent with the 26% trans and 23% cis radical cations in the ENDOR spectrum. The remainder of the ENDOR spectrum is due to several neutral radicals formed by loss of a H(+) ion from the 9, 9', 13, or 13' methyl group, a common occurrence in all water-insoluble carotenoids previously studied. Although carboxyl groups of bixin strongly affect its solubility relative to other natural carotenoids, they do not alter properties of its free radicals based on DFT calculations and EPR measurements which remain similar to typical water-insoluble carotenoids.

The membrane-bound [NiFe]-hydrogenase (Ech) from Methanosarcina barkeri: unusual properties of the iron-sulphur clusters.

PubMed

Kurkin, Sergei; Meuer, Jörn; Koch, Jürgen; Hedderich, Reiner; Albracht, Simon P J

2002-12-01

The purified membrane-bound [NiFe]-hydrogenase from Methanosarcina barkeri was studied with electron paramagnetic resonance (EPR) focusing on the properties of the iron-sulphur clusters. The EPR spectra showed signals from three different [4Fe-4S] clusters. Two of the clusters could be reduced under 101 kPa of H2, whereas the third cluster was only partially reduced. Magnetic interaction of one of the clusters with an unpaired electron localized on the Ni-Fe site indicated that this was the proximal cluster as found in all [NiFe]-hydrogenases. Hence, this cluster was assigned to be located in the EchC subunit. The other two clusters could therefore be assigned to be bound to the EchF subunit, which has two conserved four-Cys motifs for the binding of a [4Fe-4S] cluster. Redox titrations at different pH values demonstrated that the proximal cluster and one of the clusters in the EchF subunit had a pH-dependent midpoint potential. The possible relevance of these properties for the function of this proton-pumping [NiFe]-hydrogenase is discussed.

Hyperfine rather than spin splittings dominate the fine structure of the B (4)Σ(-)-X (4)Σ(-) bands of AlC.

PubMed

Clouthier, Dennis J; Kalume, Aimable

2016-01-21

Laser-induced fluorescence and wavelength resolved emission spectra of the B (4)Σ(-)-X (4)Σ(-) band system of the gas phase cold aluminum carbide free radical have been obtained using the pulsed discharge jet technique. The radical was produced by electron bombardment of a precursor mixture of trimethylaluminum in high pressure argon. High resolution spectra show that each rotational line of the 0-0 and 1-1 bands of AlC is split into at least three components, with very similar splittings and intensities in both the P- and R-branches. The observed structure was reproduced by assuming bβS magnetic hyperfine coupling in the excited state, due to a substantial Fermi contact interaction of the unpaired electron in the aluminum 3s orbital. Rotational analysis has yielded ground and excited state equilibrium bond lengths in good agreement with the literature and our own ab initio values. Small discrepancies in the calculated intensities of the hyperfine lines suggest that the upper state spin-spin constant λ' is of the order of ≈ 0.025-0.030 cm(-1).

Implementation of a handheld electronic point-of-care billing system improved efficiency in the critical care unit.

PubMed

Fahy, Brenda G; Ketzler, Jonathan T

2007-01-01

Coding and billing are time consuming and important considerations for critical care practitioners. A 1-year prospective, observational study incorporated the use of a personal digital assistant and MDeverywhere software (Hauppauge, New York) for patient coding and billing. Twelve months of data were examined before electronic implementation (pre-elec) and compared with a 12-month period after implementation (post-elec) by using an unpaired t test or z test with P < .05 considered significant. The total number of charges was 2479 pre-elec and 2243 post-elec. The days from date of service to billing for services significantly decreased from 37.8 pre-elec to 12.4 post-elec (P < .001); days in accounts receivable significantly decreased from 92.0 to 73.0 (P < .001). The net collection rate increased from 44.7% pre-elec to 49.3% post-elec (P < .001). Duplicate charges significantly decreased from 5.0% pre-elec to 1.4% post-elec ( P < .001). The return on investment was 1.97-fold (197%). The initiation of personal digital assistant technology to facilitate billing and coding resulted in significant improvements.

Benign Synthesis of Black Microspheres of Anatase TiO2 with Paramagnetic Oxygen Vacancies through NH3 Treatment.

PubMed

Maqbool, Qysar; Srivastava, Aasheesh

2017-10-09

Coloured TiO 2 is coveted for its ability to extract energy from the visible region of electromagnetic spectrum. Here a facile synthesis of black anatase titania microspheres (B-TiO 2 ) through a two-step process is reported. In the first step, amorphous white TiO 2 microspheres (W-TiO 2 ) are obtained by hydrolysing titanium tetraisopropoxide by ammonia vapours in ethanol. In the second step, the W-TiO 2 is thermally annealed at 500 °C to obtain B-TiO 2 . The diffuse reflectance analysis showed that B-TiO 2 absorbs across visible spectrum with absorption extending well into NIR region. Raman scattering together with EPR analysis showed compelling evidence of the existence of oxygen deficiency within the crystal in B-TiO 2 that induces black colouration in the sample. The defects present in the black anatase sample were confirmed to be single-electron-trapped (or paramagnetic) oxygen vacancies (V o ⋅) by XPS and EPR studies. The magnetic susceptibility studies showed existence of antiferromagnetic interactions between these unpaired electron spins. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nitroxides as Antioxidants and Anticancer Drugs

PubMed Central

Lewandowski, Marcin; Gwozdzinski, Krzysztof

2017-01-01

Nitroxides are stable free radicals that contain a nitroxyl group with an unpaired electron. In this paper, we present the properties and application of nitroxides as antioxidants and anticancer drugs. The mostly used nitroxides in biology and medicine are a group of heterocyclic nitroxide derivatives of piperidine, pyrroline and pyrrolidine. The antioxidant action of nitroxides is associated with their redox cycle. Nitroxides, unlike other antioxidants, are characterized by a catalytic mechanism of action associated with a single electron oxidation and reduction reaction. In biological conditions, they mimic superoxide dismutase (SOD), modulate hemoprotein’s catalase-like activity, scavenge reactive free radicals, inhibit the Fenton and Haber-Weiss reactions and suppress the oxidation of biological materials (peptides, proteins, lipids, etc.). The use of nitroxides as antioxidants against oxidative stress induced by anticancer drugs has also been investigated. The application of nitroxides and their derivatives as anticancer drugs is discussed in the contexts of breast, hepatic, lung, ovarian, lymphatic and thyroid cancers under in vivo and in vitro experiments. In this article, we focus on new natural spin-labelled derivatives such as camptothecin, rotenone, combretastatin, podophyllotoxin and others. The applications of nitroxides in the aging process, cardiovascular disease and pathological conditions were also discussed. PMID:29165366

Attending Physician Remote Access of the Electronic Health Record and Implications for Resident Supervision: A Mixed Methods Study.

PubMed

Martin, Shannon K; Tulla, Kiara; Meltzer, David O; Arora, Vineet M; Farnan, Jeanne M

2017-12-01

Advances in information technology have increased remote access to the electronic health record (EHR). Concurrently, standards defining appropriate resident supervision have evolved. How often and under what circumstances inpatient attending physicians remotely access the EHR for resident supervision is unknown. We described a model of attending remote EHR use for resident supervision, and quantified the frequency and magnitude of use. Using a mixed methods approach, general medicine inpatient attendings were surveyed and interviewed about their remote EHR use. Frequency of use and supervisory actions were quantitatively examined via survey. Transcripts from semistructured interviews were analyzed using grounded theory to identify codes and themes. A total of 83% (59 of 71) of attendings participated. Fifty-seven (97%) reported using the EHR remotely, with 54 (92%) reporting they discovered new clinical information not relayed by residents via remote EHR use. A majority (93%, 55 of 59) reported that this resulted in management changes, and 54% (32 of 59) reported making immediate changes by contacting cross-covering teams. Six major factors around remote EHR use emerged: resident, clinical, educational, personal, technical, and administrative. Attendings described resident and clinical factors as facilitating "backstage" supervision via remote EHR use. In our study to assess attending remote EHR use for resident supervision, attendings reported frequent remote use with resulting supervisory actions, describing a previously uncharacterized form of "backstage" oversight supervision. Future work should explore best practices in remote EHR use to provide effective supervision and ultimately improve patient safety.

SU-E-E-02: Dashboard for Tracking Physics Resident Progress

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

Becker, SJ

2014-06-01

Purpose: Design a system to easily and securely track the progress of medical physics residents through their residency. Paper sign-offs while offering a real signature are not easily updated or summarized. A resident or mentor needs to be able to quickly assess what the current assignments are, what are overdue, and whether the resident is on track to complete all the tasks in a timely fashion. An electronic version can accomplish all these goals. Methods: An electronic dashboard was created in excel to not only house the tasks and sign-off but to succinctly summarize the residents progress. The first tabmore » contains the dashboard which displays tables of the progress of the residents in each rotation, their current task, and overdue tasks. It also displays the last meetings with the residents, and timeline of important items, and a burn-down chart of the remaining tasks. This are all tied to the data and current date which auto fills the tables. The second tab contains the data. This is comprised of lists of rotations and their associated tasks along with their due dates. A signature column was also created which is password protected but allows special subset users i.e. mentors to alter without using a password. Results: The dashboard has allowed residents to better track their progress and tells them what they should be working on. It has also allowed the mentors and the program director to rapid assess their progress. Conclusion: The dashboard is successful and has been created to allow easy addition and subtraction of required tasks as the residency evolves. The next step is to create a web app version of the excel sheet with logins.« less

Evaluation of the training capacity of the Spanish Resident Book of Otolaryngology (FORMIR) as an electronic portfolio.

PubMed

Maza Solano, Juan Manuel; Benavente Bermudo, Gustavo; Estrada Molina, Francisco José; Ambrosiani Fernández, Jesús; Sánchez Gómez, Serafín

2017-08-10

and objectives We have evaluated the training capacity of the Spanish resident training book as an electronic portfolio to achieve the learning objectives of otorhinolaryngology (ENT) residents. A multi-method qualitative investigation with transversal characteristics, temporal and retrospective guidance was performed on Spanish ENT residents using a structured questionnaire, a semi-structured interview, and a computer application on the FORMIR website. A 56.5% of ENT-residents specialising in one of the 63 accredited Spanish hospitals between 2009-2012 participated in the study. The results obtained show that the ENT residents who used the e-portfolio were better able to implement self-guided study, were more aware of their learning objectives, fulfilled the training programme more efficiently, identified the causes of learning gaps more clearly, and considered FORMIR in e-portfolio format to be an ideal training tool to replace the resident training book in paper format. The ENT residents greatly appreciated the training benefits of FORMIR as an e-portfolio, especially its simple and intuitive interface, the ease and comfort with which they could record their activities, the automatic and numeric feedback on the acquisition of their competencies (which facilitates self-guided learning), its storage capacity for evidence, and its ability to be used as UEMS logbook as well as a standard curriculum vitae. All these features make FORMIR a training and evaluation tool that outperforms similar instruments available to ENT residents. They do not hesitate to identify it as the ideal resident training book for facilitating their specialised training. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Minimally invasive surgery in veterinary practice: a 2010 survey of diplomates and residents of the American College of Veterinary Surgeons.

PubMed

Bleedorn, Jason A; Dykema, Jennifer L; Hardie, Robert J

2013-08-01

To report the current state of minimally invasive surgery (MIS) in veterinary surgical practice in 2010. Electronic questionnaire. Diplomates and residents of the American College of Veterinary Surgeons (ACVS). A survey (38 questions for Diplomates, 23 questions for residents) was sent electronically to 1216 Diplomates and 300 residents. Questions were organized into 5 categories to investigate: (1) caseload and distribution of MIS cases; (2) MIS training; (3) MIS benefits, morbidity, limitations and motivating factors; (4) ACVS role; and (5) demographics of the study population. Eighty-six percent of small animal (SA) Diplomates, 99% of large animal (LA) Diplomates, and 98% of residents had performed MIS. Median LA caseload (30 cases/year; range, 1-600) was significantly higher than SA caseload (20 cases/year; range, 1-350). Descending order of case distribution was: arthroscopy > laparoscopy > endoscopic upper airway > thoracoscopy. Sixty percent of Diplomates and 98% of residents received MIS training during their residency. Residents' perspective of MIS training proficiency was positively correlated to caseload. Ninety-five percent of all respondents felt postoperative morbidity was less with MIS, and were motivated by patient benefits, maintaining a high standard of care, and personal interests. Fifty-eight percent of Diplomates and 89% of residents felt ACVS should be involved in developing MIS training. MIS is widely used by ACVS Diplomates and residents in clinical practice; however, important differences exist between SA and LA surgeons and practice types. MIS training in partnership with the ACVS is needed for continued development in veterinary surgery. © Copyright 2013 by The American College of Veterinary Surgeons.

Neurosurgery Residency Websites: A Critical Evaluation.

PubMed

Skovrlj, Branko; Silvestre, Jason; Ibeh, Chinwe; Abbatematteo, Joseph M; Mocco, J

2015-09-01

To evaluate the accessibility of educational and recruitment content of Neurosurgery Residency Websites (NRWs). Program lists from the Fellowship and Residency Electronic Interactive Database (FREIDA), Electronic Residency Application Service (ERAS), and the American Association of Neurological Surgeons (AANS) were accessed for the 2015 Match. These databases were assessed for accessibility of information and responsive program contacts. Presence of online recruitment and education variables was assessed, and correlations between program characteristics and website comprehensiveness were made. All 103 neurosurgery residency programs had an NRW. The AANS database provided the most number of viable website links with 65 (63%). No links existed for 5 (5%) programs. A minority of programs contacts responded via e-mail (46%). A minority of recruitment (46%) and educational (49%) variables were available on the NRWs. Larger programs, as defined by the number of yearly residency spots and clinical faculty, maintained greater online content than smaller programs. Similar trends were seen with programs affiliated with a ranked medical school and hospital. Multiple prior studies have demonstrated that medical students applying to neurosurgery rely heavily on residency program websites. As such, the paucity of content on NRWs allows for future opportunity to optimize online resources for neurosurgery training. Making sure that individual programs provide relevant content, make the content easier to find and adhere to established web design principles could increase the usability of NRWs. Copyright © 2015 Elsevier Inc. All rights reserved.

The new Zintl phases Eu{sub 21}Cd{sub 4}Sb{sub 18} and Eu{sub 21}Mn{sub 4}Sb{sub 18}

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

Wang, Yi; Darone, Gregory M.; Bobev, Svilen, E-mail: bobev@udel.edu

Crystals of two new Zintl compounds, Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} have been synthesized using the molten metal flux method, and their structures have been established by single-crystal X-ray diffraction. Both compounds are isotypic and crystallize in the monoclinic space group C2/m (No. 12, Z=4). The structures are based on edge- and corner-shared MnSb{sub 4} or CdSb{sub 4} tetrahedra, which make octameric [Mn{sub 8}Sb{sub 22}] or [Cd{sub 8}Sb{sub 22}] polyanions. Homoatomic Sb–Sb bonds are present in both structures. The Eu atoms take the role of Eu{sup 2+}cations with seven unpaired 4f electrons, as suggested by themore » temperature-dependent magnetization measurements. The magnetic susceptibilities of Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} indicate that both phases order anti-ferromagnetically with Néel temperatures of ca. 7 K and ca. 10 K, respectively. The unpaired 3d electrons of the Mn atoms in Eu{sub 21}Mn{sub 4}Sb{sub 18} do contribute to the magnetic response, however, the bulk magnetization measurements do not provide evidence for long-range ordering of the Mn spins down to 5 K. Electrical resistivity measurements suggest that both compounds are narrow band gap semiconductors. - Graphical abstract: Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} have complex monoclinic structures, based on MnSb{sub 4} and CdSb{sub 4} tetrahedra, both edge- and corner-shared. A perspective of the crystal structure is shown, as viewed along the b axis. Display Omitted - Highlights: • Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} are novel compounds in the respective ternary phase diagrams. • For both structures, the Zintl-Klemm rules are followed, and both are small gap semiconductors. • Eu{sub 21}Mn{sub 4}Sb{sub 18} and Eu{sub 21}Cd{sub 4}Sb{sub 18} are air-stable Zintl phases and could be new thermoelectric materials.« less

Electron Paramagnetic Resonance Spectroscopic Study on Nonequilibrium Reaction Pathways in the Photolysis of Solid Nitromethane (CH3NO2) and D3-Nitromethane (CD3NO2).

PubMed

Tsegaw, Yetsedaw Andargie; Sander, Wolfram; Kaiser, Ralf I

2016-03-10

Thin films of nitromethane (CH3NO2) along with its isotopically labeled counterpart D3-nitromethane (CD3NO2) were photolyzed at discrete wavelength between 266 nm (4.7 eV) and 121 nm (10.2 eV) to explore the underlying mechanisms involved in the decomposition of model compounds of energetic materials in the condensed phase at 5 K. The chemical modifications of the ices were traced in situ via electron paramagnetic resonance, thus focusing on the detection of (hitherto elusive) reaction intermediates and products with unpaired electrons. These studies revealed the formation of two carbon-centered radicals [methyl (CH3), nitromethyl (CH2NO2)], one oxygen-centered radical [methoxy (CH3O)], two nitrogen-centered radicals [nitrogen monoxide (NO), nitrogen dioxide (NO2)], as well as atomic hydrogen (H). The decomposition products of these channels and the carbon-centered nitromethyl (CH2NO2) radical in particular represent crucial reaction intermediates leading via sequential molecular mass growth processes in the exposed nitromethane samples to complex organic molecules as predicted previously by dynamics calculations. The detection of the nitromethyl (CH2NO2) radical along with atomic hydrogen (H) demonstrated the existence of a high-energy decomposition pathway, which is closed under collisionless conditions in the gas phase.

Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

NASA Astrophysics Data System (ADS)

Tegafaw, Tirusew; Xu, Wenlong; Wasi Ahmad, Md; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

2015-09-01

A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd3+ (8S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy3+ (6H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd3+ and Dy3+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (davg = 1.0 nm) showed large r1 and r2 values (r2/r1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R1 and R2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T1 and T2 MR images.

A comprehensive overview on the structure and comparison of magnetic properties of nanocrystalline synthesized by a thermal treatment method

NASA Astrophysics Data System (ADS)

Naseri, Mahmoud Goodarz; Halimah, M. K.; Dehzangi, Arash; Kamalianfar, Ahmad; Saion, Elias B.; Majlis, Burhanuddin Y.

2014-03-01

This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn and Co) nanostructures by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidon) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The pyrolytic behaviors of the polymeric precursor were analyzed by use of simultaneous thermo-gravimetry analyses (TGA) and derivative thermo-gravimetry (DTG) analyses. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited different types of magnetic behavior. The present study also substantiated that magnetic properties of ferrite nanoparticles prepared by the thermal treatment method, from viewing microstructures of them, can be explained as the results of the two important factors: cation distribution and impurity phase of α-Fe2O3. These two factors are subcategory of the preparation method which is related to macrostructure of ferrite. Electron paramagnetic resonance (EPR) spectroscopy showed the existence of unpaired electrons ZnFe2O4 and MnFe2O4 nanoparticles while it did not exhibit resonance signal for CoFe2O4 nanoparticles.

Association Between Patient- Centered Medical Home Features and Satisfaction With Family Medicine Residency Training in the US.

PubMed

Carney, Patricia A; Waller, Elaine; Dexter, Eve; Marino, Miguel; Rosener, Stephanie E; Green, Larry A; Jones, Geoffrey; M Keister, J Drew; Dostal, Julie A; Jones, Samuel M; Eiff, M Patrice

2016-11-01

Primary care residencies are undergoing dramatic changes because of changing health care systems and evolving demands for updated training models. We examined the relationships between residents' exposures to patient-centered medical home (PCMH) features in their assigned continuity clinics and their satisfaction with training. Longitudinal surveys were collected annually from residents evaluating satisfaction with training using a 5-point Likert-type scale (1=very unsatisfied to 5=very satisfied) from 2007 through 2011, and the presence or absence of PCMH features were collected from 24 continuity clinics during the same time period. Odds ratios on residents' overall satisfaction were compared according to whether they had no exposure to PCMH features, some exposure (1-2 years), or full exposure (all 3 or more years). Fourteen programs and 690 unique residents provided data to this study. Resident satisfaction with training was highest with full exposure for integrated case management compared to no exposure, which occurred in 2010 (OR=2.85, 95% CI=1.40, 5.80). Resident satisfaction was consistently statistically lower with any or full exposure (versus none) to expanded clinic hours in 2007 and 2009 (eg, OR for some exposure in 2009 was 0.31 95% CI=0.19, 0.51, and OR for full exposure 0.28 95% CI=0.16, 0.49). Resident satisfaction for many electronic health record (EHR)-based features tended to be significantly lower with any exposure (some or full) versus no exposure over the study period. For example, the odds ratio for resident satisfaction was significantly lower with any exposure to electronic health records in continuity practice in 2008, 2009, and 2010 (OR for some exposure in 2008 was 0.36; 95% CI=0.19, 0.70, with comparable results in 2009, 2010). Resident satisfaction with training was inconsistently correlated with exposure to features of PCMH. No correlation between PCMH exposure and resident satisfaction was sustained over time.

Electronic mail was not better than postal mail for surveying residents and faculty.

PubMed

Akl, Elie A; Maroun, Nancy; Klocke, Robert A; Montori, Victor; Schünemann, Holger J

2005-04-01

To compare response rate, time to response, and data quality of electronic and postal surveys in the setting of postgraduate medical education. A randomized controlled trial in a university-based internal medicine residency program. We randomized 119 residents and 83 faculty to an electronic versus a postal survey with up to two reminders and measured response rate, time to response, and data quality. For residents, the e-survey resulted in a lower response rate than the postal survey (63.3% versus 79.7%; difference -16.3%, 95% confidence interval (95% CI) -32.3% to -0.4%%; P=.049), but a shorter mean response time, by 3.8 days (95% CI 0.2-7.4; P=.042). For faculty, the e-survey did not result in a significantly lower response rate than the postal survey (85.4% vs. 81.0%; difference 4.4%, 95% CI -11.7 to 20.5%; P=.591), but resulted in a shorter average response time, by 8.4 days (95% CI 4.4 to 12.4; P < 0.001). There were no differences in the quality of data or responses to the survey between the two methods. E-surveys were not superior to postal surveys in terms of response rate, but resulted in shorter time to response and equivalent data quality.

Anonymity and Electronics: Adapting Preparation for Radiology Resident Examination.

PubMed

Chapman, Teresa; Reid, Janet R; O'Conner, Erin E

2017-06-01

Diagnostic radiology resident assessment has evolved from a traditional oral examination to computerized testing. Teaching faculty struggle to reconcile the differences between traditional teaching methods and residents' new preferences for computerized testing models generated by new examination styles. We aim to summarize the collective experiences of senior residents at three different teaching hospitals who participated in case review sessions using a computer-based, interactive, anonymous teaching tool, rather than the Socratic method. Feedback was collected from radiology residents following participation in a senior resident case review session using Nearpod, which allows residents to anonymously respond to the teaching material. Subjective resident feedback was uniformly enthusiastic. Ninety percent of residents favor a case-based board review incorporating multiple-choice questions, and 94% favor an anonymous response system. Nearpod allows for inclusion of multiple-choice questions while also providing direct feedback to the teaching faculty, helping to direct the instruction and clarify residents' gaps in knowledge before the Core Examination. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Right Brain: The E-lephant in the room: One resident's challenge in transitioning to modern electronic medicine.

PubMed

Strowd, Roy E

2014-09-23

The electronic medical record (EMR) is changing the landscape of medical practice in the modern age. Increasing emphasis on quality metric reporting, data-driven documentation, and timely coding and billing are pressuring institutions across the country to adopt the latest EMR technology. The impact of these systems on the patient-physician relationship is profound. One year following the latest EMR transition, one resident reviews his experience and provides a personal perspective on the impact the EMR on patient-physician communication. © 2014 American Academy of Neurology.

Benefits of an Electronic Consultation-Liaison Note System: Better Notes Faster

ERIC Educational Resources Information Center

Sola, Christopher L.; Bostwick, J. Michael; Sampson, Shirlene

2007-01-01

Objective: The authors determined the efficiency of electronic documentation in consultation-liaison psychiatry. METHOD: An electronic note system was customized for a psychiatric consultation note. Specific attention given to common diagnoses permitted rapid documentation. Results: Residents learned the system quickly. The standardized nature of…

Effects of electronic health record use on the exam room communication skills of resident physicians: a randomized within-subjects study.

PubMed

Taft, Teresa; Lenert, Leslie; Sakaguchi, Farrant; Stoddard, Gregory; Milne, Caroline

2015-01-01

The effects of electronic health records (EHRs) on doctor-patient communication are unclear. To evaluate the effects of EHR use compared with paper chart use, on novice physicians' communication skills. Within-subjects randomized controlled trial using observed structured clinical examination methods to assess the impact of use of an EHR on communication. A large academic internal medicine training program. First-year internal medicine residents. Residents interviewed, diagnosed, and initiated treatment of simulated patients using a paper chart or an EHR on a laptop computer. Video recordings of interviews were rated by three trained observers using the Four Habits scale. Thirty-two residents completed the study and had data available for review (61.5% of those enrolled in the residency program). In most skill areas in the Four Habits model, residents performed at least as well using the EHR and were statistically better in six of 23 skills areas (p<0.05). The overall average communication score was better when using an EHR: mean difference 0.254 (95% CI 0.05 to 0.45), p = 0.012, Cohen's d of 0.47 (a moderate effect). Residents scoring poorly (>3 average score) with paper methods (n = 8) had clinically important improvement when using the EHR. This study was conducted in first-year residents in a training environment using simulated patients at a single institution. Use of an EHR on a laptop computer appears to improve the ability of first-year residents to communicate with patients relative to using a paper chart. © The Author 2014. Published by Oxford University Press on behalf of the American Medical Informatics Association.

Effects of electronic health record use on the exam room communication skills of resident physicians: a randomized within-subjects study

PubMed Central

Taft, Teresa; Lenert, Leslie; Sakaguchi, Farrant; Stoddard, Gregory; Milne, Caroline

2015-01-01

Background The effects of electronic health records (EHRs) on doctor–patient communication are unclear. Objective To evaluate the effects of EHR use compared with paper chart use, on novice physicians’ communication skills. Design Within-subjects randomized controlled trial using observed structured clinical examination methods to assess the impact of use of an EHR on communication. Setting A large academic internal medicine training program. Population First-year internal medicine residents. Intervention Residents interviewed, diagnosed, and initiated treatment of simulated patients using a paper chart or an EHR on a laptop computer. Video recordings of interviews were rated by three trained observers using the Four Habits scale. Results Thirty-two residents completed the study and had data available for review (61.5% of those enrolled in the residency program). In most skill areas in the Four Habits model, residents performed at least as well using the EHR and were statistically better in six of 23 skills areas (p<0.05). The overall average communication score was better when using an EHR: mean difference 0.254 (95% CI 0.05 to 0.45), p = 0.012, Cohen's d of 0.47 (a moderate effect). Residents scoring poorly (>3 average score) with paper methods (n = 8) had clinically important improvement when using the EHR. Limitations This study was conducted in first-year residents in a training environment using simulated patients at a single institution. Conclusions Use of an EHR on a laptop computer appears to improve the ability of first-year residents to communicate with patients relative to using a paper chart. PMID:25336596

Electronic Residency Application Service Application Characteristics Associated with Successful Residency Matching in Neurosurgery in 2009-2016.

PubMed

Leschke, John M; Hunt, Matthew A

2018-05-01

Resident applicants in neurosurgery often wonder what factors impact their chances of successfully matching. Using data published by the National Residency Match Program for 2009-2016, we examined which components of the Electronic Residency Application Service application correlated with successful residency matching. Data were collected from the National Residency Match Program publication Charting Outcomes in the Match from all years it was available for neurosurgery (2009, 2011, 2014, 2016). Individual factors reported (number of contiguous ranks, research projects, publications and presentations, work experiences, volunteer experiences, United States Medical Licensing Examination Step 1 and 2 score deciles, categorical data about Alpha Omega Alpha status, Ph.D. degree, other degree, and strength of medical school National Institutes of Health funding) were aggregated for all 3 years. Categorical data were available only for U.S. seniors. Spearman correlation and χ 2 were used for ranked data and categorical data, respectively. Separate analyses were run for U.S. seniors and independent applicants. For U.S. seniors applying to neurosurgery, number of contiguous ranks, United States Medical Licensing Examination Step 1 and 2 scores, research projects, Alpha Omega Alpha status, and medical school top 40 National Institutes of Health funding were significantly associated with successful matching of applicants. Number of volunteer experiences was nearly statistically significant. For independent applicants, only United States Medical Licensing Examination Step 1 and 2 scores and number of research projects were statistically significant. This is the first study to analyze National Residency Match Program data for predictors of success in neurosurgical matching. Students applying to neurosurgery residency and their mentors should be aware of which baseline objective factors are associated with match success. Copyright © 2018 Elsevier Inc. All rights reserved.

Simple model for lambda-doublet propensities in bimolecular reactions

NASA Technical Reports Server (NTRS)

Bronikowski, Michael J.; Zare, Richard N.

1990-01-01

A simple geometric model is presented to account for lambda-doublet propensities in bimolecular reactions A + BC - AB + C. It applies to reactions in which AB is formed in a pi state, and in which the unpaired molecular orbital responsible for lambda-doubling arises from breaking the B-C bond. The lambda-doublet population ratio is predicted to be 2:1 provided that: (1) the motion of A in the transition state determines the plane of rotation of AB; (2) the unpaired pi orbital lying initially along the B-C bond may be resolved into a projection onto the AB plane of rotation and a projection perpendicular to this plane; (3) there is no preferred geometry for dissociation of ABC. The 2:1 lambda-doublet ratio is the 'unconstrained dynamics prior' lambda-doublet distribution for such reactions.

Branchpoint expansion in a fully complementary three-way DNA junction.

PubMed

Sabir, Tara; Toulmin, Anita; Ma, Long; Jones, Anita C; McGlynn, Peter; Schröder, Gunnar F; Magennis, Steven W

2012-04-11

Branched nucleic acid molecules serve as key intermediates in DNA replication, recombination, and repair; architectural elements in RNA; and building blocks and functional components for nanoscience applications. Using a combination of high-resolution single-molecule FRET, time-resolved spectroscopy, and molecular modeling, we have probed the local and global structure of a DNA three-way junction (3WJ) in solution. We found that it adopts a Y-shaped, pyramidal structure, in which the bases adjacent to the branchpoint are unpaired, despite the full Watson-Crick complementarity of the molecule. The unpairing allows a nanoscale cavity to form at the junction center. Our structure accounts for earlier observations made of the structure, flexibility, and reactivity of 3WJs. We anticipate that these results will guide the development of new DNA-based supramolecular receptors and nanosystems. © 2012 American Chemical Society

Amygdala c-Fos induction corresponds to unconditioned and conditioned aversive stimuli but not to freezing.

PubMed

Holahan, Matthew R; White, Norman M

2004-06-04

These experiments examined the relationship between freezing and c-Fos expression in the amygdala. In Experiment 1 freezing was elevated during a period immediately following shock in rats that remained in the shock context, but not in rats that were moved to a different, neutral context. The two groups showed equally elevated c-Fos levels in both the central (CeA) and lateral (LA) nuclei. In Experiment 2 rats were shocked in one compartment (paired) and not shocked in another, distinct compartment (unpaired). Rats re-exposed to the paired compartment 24h later froze more than rats exposed to the unpaired compartment, and rats in both groups froze more than un-shocked rats. c-Fos protein expression in CeA, LA and basolateral (BLA) nucleus was elevated in the rats exposed to the paired compartment but not in rats exposed to the unpaired compartment. Thus, c-Fos expression was induced by exposure to both unconditioned and conditioned stimuli, although it is unclear if the same cell population was activated in both cases. Neither case of c-Fos expression coincided with the occurrence of freezing. c-Fos expression may represent neural activity in LA and CeA produced by exposure to unconditioned cues and activity in BLA, LA and CeA produced by conditioned cues. This activity may contribute to an aversive affective state (or "fear"). Behaviors promoted by this state, such as freezing, may be mediated in other brain areas, or by other neurons in the amygdala.

Higher-order associative processing in Hermissenda suggests multiple sites of neuronal modulation.

PubMed

Rogers, R F; Matzel, L D

1996-01-01

Two important features of modern accounts of associative learning are (1) the capacity for contextual stimuli to serve as a signal for an unconditioned stimulus (US) and (2) the capacity for a previously conditioned (excitatory) stimulus to "block" learning about a redundant stimulus when both stimuli serve as a signal for the same US. Here, we examined the process of blocking, thought by some to reflect a cognitive aspect of classical conditioning, and its underlying mechanisms in the marine mollusc Hermissenda. In two behavioral experiments, a context defined by chemosensory stimuli was made excitatory by presenting unsignalled USs (rotation) in that context. The excitatory context subsequently blocked overt learning about a discrete conditioned stimulus (CS; light) paired with the US in that context. In a third experiment, the excitability of the B photoreceptors in the Hermissenda eye, which typically increases following light-rotation pairings, was examined in behaviorally blocked animals, as well as in animals that had acquired a normal CS-US association or animals that had been exposed to the CS and US unpaired. Both the behaviorally blocked and the "normal" learning groups exhibited increases in neuronal excitability relative to unpaired animals. However, light-induced multiunit activity in pedal nerves was suppressed following normal conditioning but not in blocked or unpaired control animals, suggesting that the expression of blocking is mediated by neuronal modifications not directly reflected in B-cell excitability, possibly within an extensive network of central light-responsive interneurons.

Pavlovian conditioning enhances resistance to disruption of dogs performing an odor discrimination.

PubMed

Hall, Nathaniel J; Smith, David W; Wynne, Clive D L

2015-05-01

Domestic dogs are used to aid in the detection of a variety of substances such as narcotics and explosives. Under real-world detection situations there are many variables that may disrupt the dog's performance. Prior research on behavioral momentum theory suggests that higher rates of reinforcement produce greater resistance to disruption, and that this is heavily influenced by the stimulus-reinforcer relationship. The present study tests the Pavlovian interpretation of resistance to change using dogs engaged in an odor discrimination task. Dogs were trained on two odor discriminations that alternated every six trials akin to a multiple schedule in which the reinforcement probability for a correct response was always 1. Dogs then received several sessions of either odor Pavlovian conditioning to the S+ of one odor discrimination (Pavlovian group) or explicitly unpaired exposure to the S+ of one odor discrimination (Unpaired group). The remaining odor discrimination pair for each dog always remained an unexposed control. Resistance to disruption was assessed under presession feeding, a food-odor disruptor condition, and extinction, with baseline sessions intervening between disruption conditions. Equivalent baseline detection rates were observed across experimental groups and odorant pairs. Under disruption conditions, Pavlovian conditioning led to enhanced resistance to disruption of detection performance compared to the unexposed control odor discrimination. Unpaired odor conditioning did not influence resistance to disruption. These results suggest that changes in Pavlovian contingencies are sufficient to influence resistance to change. © Society for the Experimental Analysis of Behavior.

Photoelectron Spectroscopy of Substituted Phenylnitrenes

NASA Astrophysics Data System (ADS)

Wijeratne, Neloni R.; Da Fonte, Maria; Wenthold, Paul G.

2009-06-01

Nitrenes are unusual molecular structures with unfilled electronic valences that are isoelectronic with carbenes. Although, both can be generated by either thermal or photochemical decomposition of appropriate precursors they usually exhibit different reactivities. In this work, we carry out spectroscopic studies of substituted phenylnitrene to determine how the introduction of substituents will affect the reactivity and its thermochemical properties. All studies were carried out by using the newly constructed time-of-flight negative ion photoelectron spectrometer (NIPES) at Purdue University. The 355 nm photoelectron spectra of the o-, m-, and p-chlorophenyl nitrene anions are fairly similar to that measured for phenylnitrene anion. All spectra show low energy triplet state and a high energy singlet state. The singlet state for the meta isomer is well-resolved, with a well defined origin and observable vibrational structure. Whereas the singlet states for the ortho and para isomers have lower energy onsets and no resolved structure. The isomeric dependence suggests that the geometry differences result from the resonance interaction between the nitrogen and the substituent. Quinoidal resonance structures are possible for the open-shell singlet states of the o- and p-chlorinated phenyl nitrenes. The advantages of this type of electronic structures for the open-shell singlet states is that the unpaired electrons can be more localized on separate atoms in the molecules, minimizing the repulsion between. Because the meta position is not in resonance with the nitrenes, substitution at that position should not affect the structure of the open-shell singlet state. The measured electron affinities (EA) of the triplet phenylnitrenes are in excellent agreement with the values predicted by electronic structure calculations. The largest EA, 1.82 eV is found for the meta isomer, with para being the smallest, 1.70 eV.

Interplay of spin-dependent delocalization and magnetic anisotropy in the ground and excited states of [Gd2@C78]- and [Gd2@C80]-

NASA Astrophysics Data System (ADS)

Mansikkamäki, Akseli; Popov, Alexey A.; Deng, Qingming; Iwahara, Naoya; Chibotaru, Liviu F.

2017-09-01

The magnetic properties and electronic structure of the ground and excited states of two recently characterized endohedral metallo-fullerenes, [Gd2@C78]- (1) and [Gd2@C80]- (2), have been studied by theoretical methods. The systems can be considered as [Gd2]5+ dimers encapsulated in a fullerene cage with the fifteen unpaired electrons ferromagnetically coupled into an S = 15/2 high-spin configuration in the ground state. The microscopic mechanisms governing the Gd-Gd interactions leading to the ferromagnetic ground state are examined by a combination of density functional and ab initio calculations and the full energy spectrum of the ground and lowest excited states is constructed by means of ab initio model Hamiltonians. The ground state is characterized by strong electron delocalization bordering on a σ type one-electron covalent bond and minor zero-field splitting (ZFS) that is successfully described as a second order spin-orbit coupling effect. We have shown that the observed ferromagnetic interaction originates from Hund's rule coupling and not from the conventional double exchange mechanism. The calculated ZFS parameters of 1 and 2 in their optimized geometries are in qualitative agreement with experimental EPR results. The higher excited states display less electron delocalization, but at the same time they possess unquenched first-order angular momentum. This leads to strong spin-orbit coupling and highly anisotropic energy spectrum. The analysis of the excited states presented here constitutes the first detailed study of the effects of spin-dependent delocalization in the presence of first order orbital angular momentum and the obtained results can be applied to other mixed valence lanthanide systems.

Ti2Nb10O29-x mesoporous microspheres as promising anode materials for high-performance lithium-ion batteries

NASA Astrophysics Data System (ADS)

Deng, Shengjue; Luo, Zhibin; Liu, Yating; Lou, Xiaoming; Lin, Chunfu; Yang, Chao; Zhao, Hua; Zheng, Peng; Sun, Zhongliang; Li, Jianbao; Wang, Ning; Wu, Hui

2017-09-01

Ti2Nb10O29 has recently been reported as a promising anode material for lithium-ion batteries. However, its poor electronic conductivity and insufficient Li+-ion diffusion coefficient significantly limit its rate capability. To tackle this issue, a strategy combining nanosizing and crystal-structure modification is employed. Ti2Nb10O29-x mesoporous microspheres with a sphere-size range of 0.5-4 μm are prepared by a one-step solvothermal method followed by thermal treatment in N2. These Ti2Nb10O29-x mesoporous microspheres exhibit primary nanoparticles, a large specific surface area (22.9 m2 g-1) and suitable pore sizes, leading to easy electron/Li+-ion transport and good interfacial reactivity. Ti2Nb10O29-x shows a defective shear ReO3 crystal structure with O2- vacancies and an increased unit cell volume, resulting in its increased Li+-ion diffusion coefficient. Besides Ti4+ and Nb5+ ions, Ti2Nb10O29-x comprises Nb4+ ions with unpaired 4d electrons, which significantly increase its electronic conductivity. As a result of these improvements, the Ti2Nb10O29-x mesoporous microspheres reveal superior electrochemical performances in term of large reversible specific capacity (309 mAh g-1 at 0.1 C), outstanding rate capability (235 mAh g-1 at 40 C) and durable cyclic stability (capacity retention of 92.1% over 100 cycles at 10 C).

Surgical residents' perception of competence and relevance of the clinical curriculum to future practice.

PubMed

Fronza, Jeffrey Scott; Prystowsky, Jay P; DaRosa, Debra; Fryer, Jonathan P

2012-01-01

General surgery residents maintain a case log throughout residency in order to achieve a targeted number of designated operations. Program directors must certify that each graduate is competent to enter general surgery practice without direct supervision. Our purpose was twofold, to determine: 1) graduates' perception of competence and relevance of specific operations to their practice; and 2) if case volume is related to competence. Six classes from a general surgery residency program (n=26) were surveyed one year after graduation. The survey was piloted and revised base on findings. It listed 67 operations encompassing all facets of general surgery. Each operation corresponded to two four-point scales (strongly agree to strongly disagree). One scale was headed with "I was well prepared to work-up, independently perform the operation, and effectively care for the patient post-operatively" and the other "This operation is relevant to my current practice profile". A linear regression analysis was utilized to study the relationship between total case volume and overall competence. An unpaired T-test was utilized to study the relationship between volume of specific operations and perceptions of competence. Twenty-two graduates completed the survey (85% response rate). All respondents felt prepared to perform 24% (16/67) of the operations. Fifty percent or more of respondents felt prepared to perform 91% (61/67) of the operations. Fifty percent or more did not feel competent performing the surgical treatment of necrotizing enterocolitis, orchiopexy, transhiatal esophagectomy, adrenalectomy, and open/endovascular abdominal aortic aneurysm repair. Twenty-six operations were felt to be irrelevant to the practice of 50% or more of graduates. No operation was unanimously felt to be relevant. For 12% of operations (8/67) at least 10% of graduates felt the operation was relevant to their practice but were not comfortable performing it. These operations (abdominoperineal resection, transanal excision of tumor, transhiatal esophagectomy, superficial inguinal lymph node dissection, right hepatectomy, whipple, colonoscopy, and adrenalectomy) were considered to be in need of educational improvement at a program level. After analyzing individual case logs, increased case volume only correlated with competence for esophagectomy (5 vs. 1 p = .014), EGD (32 vs. 9 p = .018), orchiopexy (2.5 vs. 0 p = .03), and adrenalectomy (3 vs. 1 p = .001). Total major operations performed did not correlate with overall competence (p = .12). As program directors must document graduates' competency they must do so with confidence. Our results suggest graduates to not feel competent performing many operations, and several are relevant to their practice. Competence in all aspects of general surgery may be unrealistic, even with robust volume. These findings might help in the restructuring curricula of residency. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

A novel use of the discrete templated notes within an electronic health record software to monitor resident supervision.

PubMed

Ban, Vin Shen; Madden, Christopher J; Browning, Travis; O'Connell, Ellen; Marple, Bradley F; Moran, Brett

2017-04-01

Monitoring the supervision of residents can be a challenging task. We describe our experience with the implementation of a templated note system for documenting procedures with the aim of enabling automated, discrete, and standardized capture of documentation of supervision of residents performing floor-based procedures, with minimal extra effort from the residents. Procedural note templates were designed using the standard existing template within a commercial electronic health record software. Templates for common procedures were created such that residents could document every procedure performed outside of the formal procedural areas. Automated reports were generated and letters were sent to noncompliers. A total of 27 045 inpatient non-formal procedural area procedures were recorded from August 2012 to June 2014. Compliance with NoteWriter template usage averaged 86% in the first year and increased to 94.6% in the second year ( P  = .0055). Initially, only 12.5% of residents documented supervision of any form. By the end of the first year, this was above 80%, with the gains maintained into the second year and beyond. Direct supervision was documented to have occurred where required in 62.8% in the first year and increased to 99.8% in the second year ( P  = .0001) after the addition of hard stops. Notification of attendings prior to procedures was documented 100% of the time by September 2013. Letters sent to errant residents decreased from 3.6 to 0.83 per 100 residents per week. The templated procedure note system with hard stops and integrated reporting can successfully be used to improve monitoring of resident supervision. This has potential impact on resident education and patient safety. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Rural Development Through Electronic Technology.

ERIC Educational Resources Information Center

Wilson, Stanley E.

Rural Development is viewed as a process of improving the quality of life of rural residents. Quality of life has a number of aspects, but the economic is viewed as a particularly strategic one for promoting overall life quality. The economic is defined as providing jobs for rural residents. Two techniques for doing this, inducing firms to locate…

Development and Implementation of a Web-based Evaluation System for an Internal Medicine Residency Program.

ERIC Educational Resources Information Center

Rosenberg, Mark E.; Watson, Kathleen; Paul, Jeevan; Miller, Wesley; Harris, Ilene; Valdivia, Tomas D.

2001-01-01

Describes the development and implementation of a World Wide Web-based electronic evaluation system for the internal medicine residency program at the University of Minnesota. Features include automatic entry of evaluations by faculty or students into a database, compliance tracking, reminders, extensive reporting capabilities, automatic…

Interaction of resident sperm with sperm-storage tubule (SST) epithelial cell microvilli in the turkey breeder hen

USDA-ARS?s Scientific Manuscript database

Interaction of resident sperm with sperm-storage tubule (SST) epithelial cell microvilli in the turkey breeder hen M.R. Bakst*1 and C. Murphy2, 1Animal Biosciences and Biotechnology Laboratory, 2Electron & Confocal Microscopy Unit, Beltsville Area, ARS, USDA, Beltsville MD Sustained fertilization o...

Evaluation of a hybrid paper-electronic medication management system at a residential aged care facility.

PubMed

Elliott, Rohan A; Lee, Cik Yin; Hussainy, Safeera Y

2016-06-01

Objectives The aims of the study were to investigate discrepancies between general practitioners' paper medication orders and pharmacy-prepared electronic medication administration charts, back-up paper charts and dose-administration aids, as well as delays between prescribing, charting and administration, at a 90-bed residential aged care facility that used a hybrid paper-electronic medication management system. Methods A cross-sectional audit of medication orders, medication charts and dose-administration aids was performed to identify discrepancies. In addition, a retrospective audit was performed of delays between prescribing and availability of an updated electronic medication administration chart. Medication administration records were reviewed retrospectively to determine whether discrepancies and delays led to medication administration errors. Results Medication records for 88 residents (mean age 86 years) were audited. Residents were prescribed a median of eight regular medicines (interquartile range 5-12). One hundred and twenty-five discrepancies were identified. Forty-seven discrepancies, affecting 21 (24%) residents, led to a medication administration error. The most common discrepancies were medicine omission (44.0%) and extra medicine (19.2%). Delays from when medicines were prescribed to when they appeared on the electronic medication administration chart ranged from 18min to 98h. On nine occasions (for 10% of residents) the delay contributed to missed doses, usually antibiotics. Conclusion Medication discrepancies and delays were common. Improved systems for managing medication orders and charts are needed. What is known about the topic? Hybrid paper-electronic medication management systems, in which prescribers' orders are transcribed into an electronic system by pharmacy technicians and pharmacists to create medication administration charts, are increasingly replacing paper-based medication management systems in Australian residential aged care facilities. The accuracy and safety of these systems has not been studied. What does this paper add? The present study identified discrepancies between general practitioners' orders and pharmacy-prepared electronic medication administration charts, back-up paper medication charts and dose-administration aids, as well as delays between ordering, charting and administering medicines. Discrepancies and delays sometimes led to medication administration errors. What are the implications for practitioners? Facilities that use hybrid systems need to implement robust systems for communicating medication changes to their pharmacy and reconciling prescribers' orders against pharmacy-generated medication charts and dose-administration aids. Fully integrated, paperless medication management systems, in which prescribers' electronic medication orders directly populate an electronic medication administration chart and are automatically communicated to the facility's pharmacy, could improve patient safety.

Identification of pseudobulbar affect symptoms in the nursing home setting: Development and assessment of a screening tool.

PubMed

Allen, Carrie; Zarowitz, Barbara; O'Shea, Terrence; Peterson, Edward; Yonan, Charles; Waterman, Fanta

Pseudobulbar Affect (PBA) is a neurologic condition characterized by involuntary outbursts of crying and/or laughing disproportionate to patient mood or social context. Although an estimated 9% of nursing home residents have symptoms suggestive of PBA, they are not routinely screened. Our goal was to develop an electronic screening tool based upon characteristics common to nursing home residents with PBA identified through medical record data. Nursing home residents with PBA treated with dextromethorphan hydrobromide/quinidine sulfate (n = 140) were compared to age-, gender-, and dementia-diagnosis-matched controls without PBA or treatment (n = 140). Comparative categories included diagnoses, medication use and symptom documentation. Using a multivariable regression and best decision rule analysis, we found PBA in nursing home residents was associated with chart documentation of uncontrollable crying, presence of a neurologic disorder (e.g., Parkinson's disease), or by the documented presence of at least 2 of the following: stroke, severe cognitive impairment, and schizophrenia. Based on these risk factors, an electronic screening tool was created. Copyright © 2017 Elsevier Inc. All rights reserved.

Tunicamycin Prevents Cellulose Microfibril Formation in Oocystis solitaria.

PubMed

Quader, H

1984-07-01

The effect of tunicamycin (TM) on the development of the cell wall in Oocystis solitaria has been investigated. It was found that 10 micromolar TM completely stops the assembly of new microfibrils as observed at the ultrastructural level. During cell wall formation, freeze fracture replicas of the E-face of the plasma membrane reveal two major substructures: the terminal complexes (TC), paired and unpaired, and the microfibril imprints extending from unpaired TCs. In cells treated for 3 hours or longer with TM, the TCs are no longer visible, whereas microfibril imprints are still present. Because of the reported highly selective mode of action of TM, our results implicate a role for lipid-intermediates in cellulose synthesis in O. solitaria. It is assumed that TM prevents the formation of a glycoprotein which probably is a fundamental part of the TCs and may act as a primer for the assembly of the microfibrils.

The interaction between the iron-responsive element binding protein and its cognate RNA is highly dependent upon both RNA sequence and structure.

PubMed

Jaffrey, S R; Haile, D J; Klausner, R D; Harford, J B

1993-09-25

To assess the influence of RNA sequence/structure on the interaction RNAs with the iron-responsive element binding protein (IRE-BP), twenty eight altered RNAs were tested as competitors for an RNA corresponding to the ferritin H chain IRE. All changes in the loop of the predicted IRE hairpin and in the unpaired cytosine residue characteristically found in IRE stems significantly decreased the apparent affinity of the RNA for the IRE-BP. Similarly, alteration in the spacing and/or orientation of the loop and the unpaired cytosine of the stem by either increasing or decreasing the number of base pairs separating them significantly reduced efficacy as a competitor. It is inferred that the IRE-BP forms multiple contacts with its cognate RNA, and that these contacts, acting in concert, provide the basis for the high affinity of this interaction.

STM/STS Study of the Sb (111) Surface

NASA Astrophysics Data System (ADS)

Chekmazov, S. V.; Bozhko, S. I.; Smirnov, A. A.; Ionov, A. M.; Kapustin, A. A.

An Sb crystal is a Peierls insulator. Formation of double layers in the Sb structure is due to the shift of atomic planes (111) next but one along the C3 axis. Atomic layers inside the double layer are connected by covalent bonds. The interaction between double layers is determined mainly by Van der Waals forces. The cleave of an Sb single crystal used to be via break of Van der Waals bonds. However, using scanning tunneling microscopy (STM) and spectroscopy (STS) we demonstrated that apart from islands equal in thickness to the double layer, steps of one atomic layer in height also exist on the cleaved Sb (111) surface. Formation of "unpaired" (111) planes on the surface leads to a local break of conditions of Peierls transition. STS experiment reveals higher local density of states (LDOS) measured for "unpaired" (111) planes in comparison with those for the double layer.

SAD-3, a Putative Helicase Required for Meiotic Silencing by Unpaired DNA, Interacts with Other Components of the Silencing Machinery

PubMed Central

Hammond, Thomas M.; Xiao, Hua; Boone, Erin C.; Perdue, Tony D.; Pukkila, Patricia J.; Shiu, Patrick K. T.

2011-01-01

In Neurospora crassa, genes lacking a pairing partner during meiosis are suppressed by a process known as meiotic silencing by unpaired DNA (MSUD). To identify novel MSUD components, we have developed a high-throughput reverse-genetic screen for use with the N. crassa knockout library. Here we describe the screening method and the characterization of a gene (sad-3) subsequently discovered. SAD-3 is a putative helicase required for MSUD and sexual spore production. It exists in a complex with other known MSUD proteins in the perinuclear region, a center for meiotic silencing activity. Orthologs of SAD-3 include Schizosaccharomyces pombe Hrr1, a helicase required for RNAi-induced heterochromatin formation. Both SAD-3 and Hrr1 interact with an RNA-directed RNA polymerase and an Argonaute, suggesting that certain aspects of silencing complex formation may be conserved between the two fungal species. PMID:22384347

Spin conversion of positronium in NiO/Al2O3 catalysts observed by coincidence Doppler broadening technique

NASA Astrophysics Data System (ADS)

Zhang, H. J.; Chen, Z. Q.; Wang, S. J.; Kawasuso, A.; Morishita, N.

2010-07-01

High-purity NiO/Al2O3 catalysts were prepared by mixing NiO and γ-Al2O3 nanopowders. X-ray diffraction patterns were measured to characterize the grain size and crystalline phase of the nanopowders. Positron-annihilation spectroscopy was used to study the microstructure and surface properties of the pores inside the NiO/Al2O3 catalysts. The positron lifetime spectrum comprises two short and two long lifetime components. The two long lifetimes τ3 and τ4 correspond to ortho-positronium (o-Ps) annihilated in microvoids and large pores, respectively. With increasing NiO content in the NiO/Al2O3 catalysts, both τ4 and its intensity I4 show continuous decrease. Meanwhile, the para-positronium (p-Ps) intensity, obtained from coincidence Doppler broadening spectra, increases gradually with NiO content. The different variation in o-Ps and p-Ps intensity suggests the ortho-para conversion of positronium in NiO/Al2O3 catalysts. X-ray photoelectron spectroscopy shows that Ni mainly exists in the form of NiO. The electron-spin-resonance measurements reveal that the ortho-para conversion of Ps is induced by the unpaired electrons of the paramagnetic centers of NiO.

Comparative analysis of the H 2 passivation of interface defects at the {(100) Si}/{SiO 2} interface using electron spin resonance

NASA Astrophysics Data System (ADS)

Stesmans, A.

1996-01-01

The passivation with molecular hydrogen in the range 213-234°C of the interfacial Pb0 and Pb1 defects in {(100) Si}/{SiO 2}, thermally grown at low temperature (<750°C), has been analyzed by K-band electron spin resonance. The passivation kinetics are found to be well described by the same defect-H 2 reaction limited model applying to the interfacial Pb defect (∘SiSi 3) in {(111) Si}/{SiO 2} grown at 850°C. However, unlike Pb, that was typified by a single-valued activation energy for passivation Ea = 1.66 eV, both Pb0 and Pb1 are found to exhibit a Gaussian spread σEa ˜ 0.15 eV around their respective meanEa values, deduced as 1.51 and 1.57 ± 0.3 eV. The similar passivation kinetics are in line with assigning the Pb0 and Pb1 defects, like Pb, to an interfacial unpaired sp3 Si hybrid. However, as there is no fundamental difference between Pb0 and Pb1 regarding passivation in H 2, more specfic identification of Pb with either Pb0 or Pb1 , if any, cannot be concluded.

Synthesis and characterization of triangulene

NASA Astrophysics Data System (ADS)

Pavliček, Niko; Mistry, Anish; Majzik, Zsolt; Moll, Nikolaj; Meyer, Gerhard; Fox, David J.; Gross, Leo

2017-05-01

Triangulene, the smallest triplet-ground-state polybenzenoid (also known as Clar's hydrocarbon), has been an enigmatic molecule ever since its existence was first hypothesized. Despite containing an even number of carbons (22, in six fused benzene rings), it is not possible to draw Kekulé-style resonant structures for the whole molecule: any attempt results in two unpaired valence electrons. Synthesis and characterization of unsubstituted triangulene has not been achieved because of its extreme reactivity, although the addition of substituents has allowed the stabilization and synthesis of the triangulene core and verification of the triplet ground state via electron paramagnetic resonance measurements. Here we show the on-surface generation of unsubstituted triangulene that consists of six fused benzene rings. The tip of a combined scanning tunnelling and atomic force microscope (STM/AFM) was used to dehydrogenate precursor molecules. STM measurements in combination with density functional theory (DFT) calculations confirmed that triangulene keeps its free-molecule properties on the surface, whereas AFM measurements resolved its planar, threefold symmetric molecular structure. The unique topology of such non-Kekulé hydrocarbons results in open-shell π-conjugated graphene fragments that give rise to high-spin ground states, potentially useful in organic spintronic devices. Our generation method renders manifold experiments possible to investigate triangulene and related open-shell fragments at the single-molecule level.

Dynamic nuclear polarization using frequency modulation at 3.34 T.

PubMed

Hovav, Y; Feintuch, A; Vega, S; Goldfarb, D

2014-01-01

During dynamic nuclear polarization (DNP) experiments polarization is transferred from unpaired electrons to their neighboring nuclear spins, resulting in dramatic enhancement of the NMR signals. While in most cases this is achieved by continuous wave (cw) irradiation applied to samples in fixed external magnetic fields, here we show that DNP enhancement of static samples can improve by modulating the microwave (MW) frequency at a constant field of 3.34 T. The efficiency of triangular shaped modulation is explored by monitoring the (1)H signal enhancement in frozen solutions containing different TEMPOL radical concentrations at different temperatures. The optimal modulation parameters are examined experimentally and under the most favorable conditions a threefold enhancement is obtained with respect to constant frequency DNP in samples with low radical concentrations. The results are interpreted using numerical simulations on small spin systems. In particular, it is shown experimentally and explained theoretically that: (i) The optimal modulation frequency is higher than the electron spin-lattice relaxation rate. (ii) The optimal modulation amplitude must be smaller than the nuclear Larmor frequency and the EPR line-width, as expected. (iii) The MW frequencies corresponding to the enhancement maxima and minima are shifted away from one another when using frequency modulation, relative to the constant frequency experiments. Copyright © 2013 Elsevier Inc. All rights reserved.

Properties of K,Rb-intercalated C{sub 60} encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

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

Mahfouz, R.; Bouhrara, M.; Kim, Y.

2015-09-21

We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C{sub 60} encapsulated inside carbon nanotubes called peapods can be derived from {sup 13}C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shiftmore » anisotropy and spin-lattice relaxation (T{sub 1}) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C{sub 60} that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C{sub 60} at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(E{sub F})« less

Electron Spin Resonance (ESR) studies of returned comet nucleus samples

NASA Technical Reports Server (NTRS)

Tsay, Fun-Dow; Kim, Soon Sam; Liang, Ranty H.

1989-01-01

The most important objective of the Comet Nucleus Sample Returm Mission is to return samples which could reflect formation conditions and evolutionary processes in the early solar nebula. It is expected that the returned samples will consist of fine-grained silicate materials mixed with ices composed of simple molecules such as H2O, NH3, CH4 as well as organics and/or more complex compounds. Because of the exposure to ionizing radiation from cosmic-ray, gamma-ray, and solar wind protons at low temperature, free radicals are expected to be formed and trapped in the solid ice matrices. The kind of trapped radical species together with their concentration and thermal stability can be used as a dosimeter as well as a geothermometer to determine thermal and radiation histories as well as outgassing and other possible alternation effects since the nucleus material was formed. Since free radicals that are known to contain unpaired electrons are all paramagnetic in nature, they can be readily detected and characterized in their native form by the Electron Spin Resonance (ESR) method. In fact, ESR has been shown to be a non-destructive, highly sensitive tool for the detection and characterization of paramagnetic, ferromagnetic, and radiation damage centers in terrestrial and extraterrestrial geological samples. The potential use of ESR as an effective method in the study of returned comet nucleus samples, in particular, in the analysis of fine-grained solid state icy samples is discussed.

Electronic and Magnetic Properties of Ni-Doped Zinc-Blende ZnO: A First-Principles Study.

PubMed

Xue, Suqin; Zhang, Fuchun; Zhang, Shuili; Wang, Xiaoyang; Shao, Tingting

2018-04-26

The electronic structure, band structure, density of state, and magnetic properties of Ni-doped zinc-blende (ZB) ZnO are studied by using the first-principles method based on the spin-polarized density-functional theory. The calculated results show that Ni atoms can induce a stable ferromagnetic (FM) ground state in Ni-doped ZB ZnO. The magnetic moments mainly originate from the unpaired Ni 3 d orbitals, and the O 2 p orbitals contribute a little to the magnetic moments. The magnetic moment of a supercell including a single Ni atom is 0.79 μ B . The electronic structure shows that Ni-doped ZB ZnO is a half-metallic FM material. The strong spin-orbit coupling appears near the Fermi level and shows obvious asymmetry for spin-up and spin-down density of state, which indicates a significant hybrid effects from the Ni 3 d and O 2 p states. However, the coupling of the anti-ferromagnetic (AFM) state show metallic characteristic, the spin-up and spin-down energy levels pass through the Fermi surface. The magnetic moment of a single Ni atom is 0.74 μ B . Moreover, the results show that the Ni 3 d and O 2 p states have a strong p - d hybridization effect near the Fermi level and obtain a high stability. The above theoretical results demonstrate that Ni-doped zinc blende ZnO can be considered as a potential half-metal FM material and dilute magnetic semiconductors.

Characterization of point defects in monolayer arsenene

NASA Astrophysics Data System (ADS)

Liang, Xiongyi; Ng, Siu-Pang; Ding, Ning; Wu, Chi-Man Lawrence

2018-06-01

Topological defects that are inevitably found in 2D materials can dramatically affect their properties. Using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) method, the structural, thermodynamic, electronic and magnetic properties of six types of typical point defects in arsenene, i.e. the Stone-Wales defect, single and double vacancies and adatoms, were systemically studied. It was found that these defects were all more easily generated in arsenene with lower formation energies than those with graphene and silicene. Stone-Wales defects can be transformed from pristine arsenene by overcoming a barrier of 2.19 eV and single vacancy defects tend to coalesce into double vacancy defects by diffusion. However, a type of adatom defect does not exhibit kinetic stability at room temperature. In addition, SV defects and another type of adatom defect can remarkably affect the electronic and magnetic properties of arsenene, e.g. they can introduce localized states near the Fermi level, as well as a strongly local magnetic moment due to dangling bond and unpaired electron. Furthermore, the simulated scanning tunneling microscopy (STM) and Raman spectroscopy were computed and the types of point defects can be fully characterized by correlating the STM images and Raman spectra to the defective atomistic structures. The results provide significant insights to the effect of defects in arsenene for potential applications, as well as identifications of two helpful tools (STM and Raman spectroscopy) to distinguish the type of defects in arsenene for future experiments.

Effective scheme for partitioning covalent bonds in density-functional embedding theory: From molecules to extended covalent systems.

PubMed

Huang, Chen; Muñoz-García, Ana Belén; Pavone, Michele

2016-12-28

Density-functional embedding theory provides a general way to perform multi-physics quantum mechanics simulations of large-scale materials by dividing the total system's electron density into a cluster's density and its environment's density. It is then possible to compute the accurate local electronic structures and energetics of the embedded cluster with high-level methods, meanwhile retaining a low-level description of the environment. The prerequisite step in the density-functional embedding theory is the cluster definition. In covalent systems, cutting across the covalent bonds that connect the cluster and its environment leads to dangling bonds (unpaired electrons). These represent a major obstacle for the application of density-functional embedding theory to study extended covalent systems. In this work, we developed a simple scheme to define the cluster in covalent systems. Instead of cutting covalent bonds, we directly split the boundary atoms for maintaining the valency of the cluster. With this new covalent embedding scheme, we compute the dehydrogenation energies of several different molecules, as well as the binding energy of a cobalt atom on graphene. Well localized cluster densities are observed, which can facilitate the use of localized basis sets in high-level calculations. The results are found to converge faster with the embedding method than the other multi-physics approach ONIOM. This work paves the way to perform the density-functional embedding simulations of heterogeneous systems in which different types of chemical bonds are present.

Tilling the soil while sowing the seeds: combining resident education with medical home transformation.

PubMed

Muench, John; Jarvis, Kelly; Boverman, Josh; Hardman, Joseph; Hayes, Meg; Winkle, Jim

2012-01-01

In order to successfully integrate screening, brief intervention, and referral to treatment (SBIRT) into primary care, education of clinicians must be paired with sustainable transformation of the clinical settings in which they practice. The SBIRT Oregon project adopted this strategy in an effort to fully integrate SBIRT into 7 primary care residency clinics. Residents were trained to assess and intervene in their patients' unhealthy substance use, whereas clinic staff personnel were trained to carry out a multistep screening process. Electronic medical record tools were created to further integrate and track SBIRT processes. This article describes how a resident training curriculum complemented and was informed by the transformation of workflow processes within the residents' home clinics.

Education on the Brain: A Partnership Between a Pediatric Primary Care Center and Neurology Residency.

PubMed

Zwemer, Eric; Bernson-Leung, Miya; Rea, Corinna; Patel, Archana A; Guerriero, Rejean; Urion, David K; Toomey, Sara L

2018-01-01

The national shortage of pediatric neurologists is worsening, yet referral rates by pediatricians are high. Suboptimal training of pediatric residents in care of patients with neurologic disease may be a contributing factor. We formed a partnership between the Boston Children's Primary Care at Longwood clinic and Child Neurology Residency Training Program. The educational intervention included lectures, observed neurologic examinations, in-person and virtual triage, and an electronic medical record-based consult system. Residents in other primary care clinics served as the comparison group. Intervention-group residents reported significantly improved confidence in diagnosis of chronic/recurrent headache, attention deficit hyperactivity disorder (ADHD), and developmental delay; initial management of ADHD and developmental delay; and secondary management of ADHD, developmental delay, and concussion/traumatic brain injury. Comparison-group residents reported significantly improved confidence only in diagnosis of developmental delay. Our multipronged intervention is a promising approach to improving pediatric resident training in pediatric neurology and may be generalizable to subspecialty collaborations for other residency programs.

Pulsed laser photolysis study of the reaction between O(3P) and HO2

NASA Technical Reports Server (NTRS)

Ravishankara, A. R.; Wine, P. H.; Nicovich, J. M.

1983-01-01

It is pointed out that bimolecular reactions involving two free radicals are of great interest because both reactants have unpaired electrons and hence could interact at distances longer than those typical of radical-molecule encounters. A method based on laser photolysis is being developed to produce selectively free radicals in the homogeneous gas phase. This is to be done in such a way as to isolate the reaction of interest and subsequently follow the course of the reaction using spectroscopic techniques. The present investigation is concerned with a study in which the rate coefficient for the reaction of O(3P) with HO2, has been measured at N2 pressures ranging from 10 to 500 torr, taking into account the reaction O(3P)+HO2 yields OH-O2. In the described study, O(3P) and HO2 were produced by cophotolysis of O3 and H2O2 in N2 at 248.5 nm using a KrF excimer laser.

Impact of vanadium ions in barium borate glass.

PubMed

Abdelghany, A M; Hammad, Ahmed H

2015-02-25

Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data. Copyright © 2014 Elsevier B.V. All rights reserved.

Endohedral Metallofullerene as Molecular High Spin Qubit: Diverse Rabi Cycles in Gd2@C79N.

PubMed

Hu, Ziqi; Dong, Bo-Wei; Liu, Zheng; Liu, Jun-Jie; Su, Jie; Yu, Changcheng; Xiong, Jin; Shi, Di-Er; Wang, Yuanyuan; Wang, Bing-Wu; Ardavan, Arzhang; Shi, Zujin; Jiang, Shang-Da; Gao, Song

2018-01-24

An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover's algorithm can be implemented in such systems. Dimetallic aza[80]fullerenes M 2 @C 79 N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd 2 @C 79 N for the first time. This molecular magnet with a collective high-spin ground state (S = 15/2) generated by strong magnetic coupling (J Gd-Rad = 350 ± 20 cm -1 ) has been unambiguously validated by magnetic susceptibility experiments. Gd 2 @C 79 N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 μs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover's searching algorithm proposed by Leuenberger and Loss.

Laboratory detection of the C3N an C4H free radicals

NASA Technical Reports Server (NTRS)

Gottlieb, C. A.; Gottlieb, E. W.; Thaddeus, P.; Kawamura, H.

1983-01-01

The millimeter-wave spectra of the linear carbon chain free radicals C3N and C4H, first identified in IRC + 10216 and hitherto observed only in a few astronomical sources, have been detected with a Zeeman-modulated spectrometer in laboratory glow discharges through low pressure flowing mixtures of N2 + HC3N and He + HCCH, respectively. Four successive rotational transitions between 168 and 198 GHz have been measured for C3N, and five rotational transitions between 143 and 200 GHz for C4H; each is a well-resolved spin doublet owing to the unpaired electron present in both species. Precise values for the rotational, centrifugal distortion, and spin doubling constants have been obtained, which, with hyperfine constants derived from observations of the lower rotational transitions in the astronomical source TMC 1, allow all the rotational transitions of C3N and C4H at frequencies less than 300 GHz to be calculated to an absolute accuracy exceeding 1 ppm.

A new species of Aplectana (Nematoda: Cosmocercidae) parasite of Pleurodema nebulosum (Anura: Leptodactylidae) from the Monte desert, Argentina, with a key to Neotropical species of the genus Aplectana.

PubMed

Gomez, Mauricio D Piñeiro; González, Cynthya E; Sanabria, Eduardo A

2017-03-27

Here we describe a new cosmocercid nematode, Aplectana nebulosa sp. nov., from the small and large intestines of Pleurodema nebulosum (Anura: Leptodactylidae), from the Monte desert of San Juan, Argentina. The new species belongs to the Aplectana group that possesses a gubernaculum and unpaired adcloacal papilla anteriorly to cloaca. It resembles A. membranosa, A. paraelenae and A. travassosi by the presence of four adcloacal papillae, but differs from those species by the following characters: number and arrangement of precloacal papillae; number and arrangement of postcloacal papillae; shape and size of spicules and gubernaculum, and by the presence of lateral alae in caudal region of males. The description of the new species is based on light microscopy and scanning electron microscopy (SEM) and we also provide a key to Neotropical species of Aplectana.

Comparison of cellular toxicity between multi-walled carbon nanotubes and onion-like shell-shaped carbon nanoparticles

NASA Astrophysics Data System (ADS)

Kang, Seunghyon; Kim, Ji-Eun; Kim, Daegyu; Woo, Chang Gyu; Pikhitsa, Peter V.; Cho, Myung-Haing; Choi, Mansoo

2015-09-01

The cellular toxicity of multi-walled carbon nanotubes (MWCNTs) and onion-like shell-shaped carbon nanoparticles (SCNPs) was investigated by analyzing the comparative cell viability. For the reasonable comparison, physicochemical characteristics were controlled thoroughly such as crystallinity, carbon bonding characteristic, hydrodynamic diameter, and metal contents of the particles. To understand relation between cellular toxicity of the particles and generation of reactive oxygen species (ROS), we measured unpaired singlet electrons of the particles and intracellular ROS, and analyzed cellular toxicity with/without the antioxidant N-acetylcysteine (NAC). Regardless of the presence of NAC, the cellular toxicity of SCNPs was found to be lower than that of MWCNTs. Since both particles show similar crystallinity, hydrodynamic size, and Raman signal with negligible contribution of remnant metal particles, the difference in cell viability would be ascribed to the difference in morphology, i.e., spherical shape (aspect ratio of one) for SCNP and elongated shape (high aspect ratio) for MWCNT.

Larval morphology of Atherigona orientalis (Schiner) (Diptera: Muscidae) -a species of sanitary and forensic importance.

PubMed

Grzywacz, Andrzej; Pape, Thomas

2014-09-01

Larval morphology is documented using both light and scanning electron microscopy for all three instars of the muscid fly Atherigona orientalis (Schiner), which is a species of known sanitary and forensic importance found in tropical and subtropical areas of all biogeographic regions. The unpaired sclerite in a form of a spicule is reported herein in the second and the third instar larvae. Occurrence of this sclerite was hitherto unknown in the second instar larvae of Muscidae and was only known from the third instar of several species, however not in a form of a spicule. Our study is the first report of the occurrence of the "sensory organ X" in all three larval instars of a species representing the family Muscidae. The bubble membrane, previously known only from third instar cyclorrhaphan larvae, is reported herein for the first time in the second instar. Characters allowing for discrimination of A. orientalis larvae from other forensically important Muscidae are summarised. Copyright © 2014 Elsevier B.V. All rights reserved.

Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

PubMed Central

Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

2017-01-01

We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials. PMID:28262805

Paramagnetic 19F NMR and Electrospray Ionization Mass Spectrometric Studies of Substituted Pyridine Complexes of Chromium(III): Models for Potential Use of 19F NMR to Probe Cr(III)-Nucleotide Interaction1

PubMed Central

Rhodes, Nicholas R.; Belmore, Ken; Cassady, Carolyn J.; Vincent, John B.

2013-01-01

The synthesis and characterization of chromium basic carboxylate complexes, [Cr3(O2CR)6L3]+, containing trifluoroacetate, 3-fluoropyridine, 3-trifluoromethylpyridine, and 4-trifluoromethylpyridine are described. The substituted pyridine ligands are used as models of DNA bases to determine whether 19F NMR would be a potentially useful probe of the binding of Cr3+ to DNA. The 19F NMR resonances of the coordinated ligands, while broadened by delocalization of unpaired electron density from the S=3/2 chromic centers, are readily discernable, and the contact shifts are of sufficient magnitude that the signals from coordinated and free ligands can easily be differentiated. Thus, 19F NMR appears to be a potentially useful probe of the binding of Cr3+ to DNA containing F-labeled bases. Additionally, electrospray MS is shown to be a convenient method to establish the identity of chromium basic carboxylate assemblies. PMID:24222929

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

van der Eide, Edwin F.; Yang, Ping; Walter, Eric D.

Unlike the very labile, unobservable radical cations [{l_brace}CpM(CO){sub 3}{r_brace}{sub 2}]{sup {sm_bullet}+} (M = W, Mo), derivatives [{l_brace}CpM(CO){sub 2}(PMe{sub 3}){r_brace}{sub 2}]{sup {sm_bullet}+} are stable enough to be isolated and characterized. Experimental and theoretical studies show that the shortened M-M bonds are of order 1 1/2, and that they are not supported by bridging ligands. The unpaired electron is fully delocalized, with a spin density of ca. 45% on each metal atom. We thank the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences for support of this work. Pacific Northwestmore » National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. The EPR and computational studies were performed using EMSL, a national scientific user facility sponsored by the DOE's Office of Biological and Environmental Research and located at PNNL. We thank Dr. Charles Windisch for access to his UV-Vis-NIR spectrometer.« less

Magnetism of a relaxed single atom vacancy in graphene

NASA Astrophysics Data System (ADS)

Wu, Yunyi; Hu, Yonghong; Xue, Li; Sun, Tieyu; Wang, Yu

2018-04-01

It has been suggested in literature that defects in graphene (e.g. absorbed atoms and vacancies) may induce magnetizations due to unpaired electrons. The nature of magnetism, i.e. ferromagnetic or anti-ferromagnetic, is dependent on a number of structural factors including locations of magnetic moments and lattice symmetry. In the present work we investigated the influence of a relaxed single atom vacancy in garphnene on magnetization which were obtained under different pinning boundary conditions, aiming to achieve a better understanding of the magnetic behaviors of graphene. Through first principles calculations, we found that major spin polarizations occur on atoms that deviate slightly from their original lattice positions, and pinning boundaries could also affect the relaxed positions of atoms and determine which atom(s) would become the main source(s) of total spin polarizations and magnetic moments. When the pinning boundary condition is free, a special non-magnetic and semi-conductive structure may be obtained, suggesting that magnetization should more readily occur under pinning boundary conditions.

Large exchange anisotropy in quasi-one-dimensional spin-1/2 fluoride antiferromagnets with a d (z2)1 ground state

NASA Astrophysics Data System (ADS)

Kurzydłowski, D.; Grochala, W.

2017-10-01

Hybrid density functional calculations are performed for a variety of systems containing d9 ions (C u2 + and A g2 + ) and exhibiting quasi-one-dimensional magnetic properties. In particular, we study fluorides containing these ions in a rarely encountered compressed octahedral coordination that forces the unpaired electron into the local d (z2) orbital. We predict that such systems should exhibit exchange anisotropies surpassing that of S r2Cu O3 , one of the best realizations of a one-dimensional system known to date. In particular, we predict that the interchain coupling in the A g2 + -containing [AgF ] [B F4 ] system should be nearly four orders of magnitude smaller than the intrachain interaction. Our results indicate that quasi-one-dimensional spin-1/2 systems containing chains with spin sites in the d (z2)1 local ground state could constitute a versatile model for testing modern theories of quantum many-body physics in the solid state.

Handheld Computer Use in U.S. Family Practice Residency Programs

PubMed Central

Criswell, Dan F.; Parchman, Michael L.

2002-01-01

Objective: The purpose of the study was to evaluate the uses of handheld computers (also called personal digital assistants, or PDAs) in family practice residency programs in the United States. Study Design: In November 2000, the authors mailed a questionnaire to the program directors of all American Academy of Family Physicians (AAFP) and American College of Osteopathic Family Practice (ACOFP) residency programs in the United States. Measurements: Data and patterns of the use and non-use of handheld computers were identified. Results: Approximately 50 percent (306 of 610) of the programs responded to the survey. Two thirds of the programs reported that handheld computers were used in their residencies, and an additional 14 percent had plans for implementation within 24 months. Both the Palm and the Windows CE operating systems were used, with the Palm operating system the most common. Military programs had the highest rate of use (8 of 10 programs, 80 percent), and osteopathic programs had the lowest (23 of 55 programs, 42 percent). Of programs that reported handheld computer use, 45 percent had required handheld computer applications that are used uniformly by all users. Funding for handheld computers and related applications was non-budgeted in 76percent of the programs in which handheld computers were used. In programs providing a budget for handheld computers, the average annual budget per user was $461.58. Interested faculty or residents, rather than computer information services personnel, performed upkeep and maintenance of handheld computers in 72 percent of the programs in which the computers are used. In addition to the installed calendar, memo pad, and address book, the most common clinical uses of handheld computers in the programs were as medication reference tools, electronic textbooks, and clinical computational or calculator-type programs. Conclusions: Handheld computers are widely used in family practice residency programs in the United States. Although handheld computers were designed as electronic organizers, in family practice residencies they are used as medication reference tools, electronic textbooks, and clinical computational programs and to track activities that were previously associated with desktop database applications. PMID:11751806

Handheld computer use in U.S. family practice residency programs.

PubMed

Criswell, Dan F; Parchman, Michael L

2002-01-01

The purpose of the study was to evaluate the uses of handheld computers (also called personal digital assistants, or PDAs) in family practice residency programs in the United States. In November 2000, the authors mailed a questionnaire to the program directors of all American Academy of Family Physicians (AAFP) and American College of Osteopathic Family Practice (ACOFP) residency programs in the United States. Data and patterns of the use and non-use of handheld computers were identified. Approximately 50 percent (306 of 610) of the programs responded to the survey. Two thirds of the programs reported that handheld computers were used in their residencies, and an additional 14 percent had plans for implementation within 24 months. Both the Palm and the Windows CE operating systems were used, with the Palm operating system the most common. Military programs had the highest rate of use (8 of 10 programs, 80 percent), and osteopathic programs had the lowest (23 of 55 programs, 42 percent). Of programs that reported handheld computer use, 45 percent had required handheld computer applications that are used uniformly by all users. Funding for handheld computers and related applications was non-budgeted in 76percent of the programs in which handheld computers were used. In programs providing a budget for handheld computers, the average annual budget per user was 461.58 dollars. Interested faculty or residents, rather than computer information services personnel, performed upkeep and maintenance of handheld computers in 72 percent of the programs in which the computers are used. In addition to the installed calendar, memo pad, and address book, the most common clinical uses of handheld computers in the programs were as medication reference tools, electronic textbooks, and clinical computational or calculator-type programs. Handheld computers are widely used in family practice residency programs in the United States. Although handheld computers were designed as electronic organizers, in family practice residencies they are used as medication reference tools, electronic textbooks, and clinical computational programs and to track activities that were previously associated with desktop database applications.

Chaplain Documentation and the Electronic Medical Record: A Survey of ACPE Residency Programs.

PubMed

Tartaglia, Alexander; Dodd-McCue, Diane; Ford, Timothy; Demm, Charles; Hassell, Alma

2016-01-01

This study explores the extent to which chaplaincy departments at ACPE-accredited residency programs make use of the electronic medical record (EMR) for documentation and training. Survey data solicited from 219 programs with a 45% response rate and interview findings from 11 centers demonstrate a high level of usage of the EMR as well as an expectation that CPE residents document each patient/family encounter. Centers provided considerable initial training, but less ongoing monitoring of chaplain documentation. Centers used multiple sources to develop documentation tools for the EMR. One center was verified as having created the spiritual assessment component of the documentation tool from a peer reviewed published model. Interviews found intermittent use of the student chart notes for educational purposes. One center verified a structured manner of monitoring chart notes as a performance improvement activity. Findings suggested potential for the development of a standard documentation tool for chaplain charting and training.

Contrast reaction training in US radiology residencies: a COARDRI study.

PubMed

LeBedis, Christina A; Rosenkrantz, Andrew B; Otero, Hansel J; Decker, Summer J; Ward, Robert J

To perform a survey-based assessment of current contrast reaction training in US diagnostic radiology residency programs. An electronic survey was distributed to radiology residency program directors from 9/2015-11/2015. 25.7% of programs responded. 95.7% of those who responded provide contrast reaction management training. 89.4% provide didactic lectures (occurring yearly in 71.4%). 37.8% provide hands-on simulation training (occurring yearly in 82.3%; attended by both faculty and trainees in 52.9%). Wide variability in contrast reaction education in US diagnostic radiology residency programs reveals an opportunity to develop and implement a national curriculum. Copyright © 2017 Elsevier Inc. All rights reserved.

Developing and validating trace fear conditioning protocols in C57BL/6 mice.

PubMed

Burman, Michael A; Simmons, Cassandra A; Hughes, Miles; Lei, Lei

2014-01-30

Classical fear conditioning is commonly used to study the biology of fear, anxiety and memory. Previous research demonstrated that delay conditioning requires a neural circuit involving the amygdala, but not usually the hippocampus. Trace and contextual fear conditioning require the amygdala and hippocampus. While these paradigms were developed primarily using rat models, they are increasingly being used in mice. The current studies develop trace fear conditioning and control paradigms to allow for the assessment of trace and delay fear conditioning in C57BL/6N mice. Our initial protocol yielded clear delay and contextual conditioning. However, trace conditioning failed to differentiate from an unpaired group and was not hippocampus-dependent. These results suggested that the protocol needed to be modified to specifically accommodate trace conditioning the mice. In order to reduce unconditioned freezing and increase learning, the final protocol was developed by decreasing the intensity of the tone and by increasing the inter-trial interval. Our final protocol produced trace conditioned freezing that was significantly greater than that followed unpaired stimulus exposure and was disrupted by hippocampus lesions. A review of the literature produced 90 articles using trace conditioning in mice. Few of those articles used any kind of behavioral control group, which is required to rule out non-associative factors causing fearful behavior. Fewer used unpaired groups involving tones and shocks within a session, which is the optimal control group. Our final trace conditioning protocol can be used in future studies examining genetically modified C57BL/6N mice. Copyright © 2013 Elsevier B.V. All rights reserved.

Developing and Validating Trace Fear Conditioning Protocols in C57BL/6 Mice

PubMed Central

Burman, Michael A; Simmons, Cassandra A; Hughes, Miles; Lei, Lei

2013-01-01

Background Classical fear conditioning is commonly used to study the biology of fear, anxiety and memory. Previous research demonstrated that delay conditioning requires a neural circuit involving the amygdala, but not usually the hippocampus. Trace and contextual fear conditioning require the amygdala and hippocampus. While these paradigms were developed primarily using rat models, they are increasingly being used in mice. New Method The current studies develop trace fear conditioning and control paradigms to allow for the assessment of trace and delay fear conditioning in C57BL/6N mice. Our initial protocol yielded clear delay and contextual conditioning. However, trace conditioning failed to differentiate from an unpaired group and was not hippocampus-dependent. These results suggested that the protocol needed to be modified to specifically accommodate trace conditioning the mice. In order to reduce unconditioned freezing and increase learning, the final protocol was developed by decreasing the intensity of the tone and by increasing the inter-trial interval. Results Our final protocol produced trace conditioned freezing that was significantly greater than that followed unpaired stimulus exposure and was disrupted by hippocampus lesions. Comparison with Existing Methods A review of the literature produced 90 articles using trace conditioning in mice. Few of those articles used any kind of behavioral control group, which is required to rule out non-associative factors causing fearful behavior. Fewer used unpaired groups involving tones and shocks within a session, which is the optimal control group. Conclusions Our final trace conditioning protocol can be used in future studies examining genetically modified C57BL/6N mice. PMID:24269252

An automatic recording system for the study of escape from fear in rats.

PubMed

Li, Ming; He, Wei

2013-11-01

Escape from fear (EFF) is an active response to a conditioned stimulus (CS) previously paired with an unconditioned fearful stimulus (US), which typically leads to the termination of the CS. In this paradigm, animals acquire two distinct associations: S-S [CS-US] and R-O [response-outcome] through Pavlovian and instrumental conditioning, respectively. The present study describes a computer controlled automatic recording system that captures the development of EFF and allows the determination of the respective roles of S-S and R-O associations in this process. We validated this system by showing that only rats subjected to a simultaneous CS-US conditioning (i.e., CS and US occur together at the beginning of each trial) acquired EFF, not those subjected to an unpaired CS-US conditioning. Paired rats had a progressively increased number of EFF and significantly shorter escape latencies than unpaired rats across the 5-trial blocks on the test day. However, during the conditioning phase, the unpaired rats emitted more 22kHz ultrasonic vocalizations, a validated measure of conditioned reactive fear responses. Our results demonstrate that the acquisition of EFF is contingent upon pairing of the CS with the US, not simply the consequence of a high level of generalized fear. Because this commercially available system is capable of examining both conditioned active and reactive fear responses in a single setup, it could be used to determine the relative roles of S-S and R-O associations in EFF, the neurobiology of conditioned active fear response and neuropharmacology of psychotherapeutic drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Emergency Medicine Resident Physicians’ Perceptions of Electronic Documentation and Workflow

PubMed Central

Neri, P.M.; Redden, L.; Poole, S.; Pozner, C.N.; Horsky, J.; Raja, A.S.; Poon, E.; Schiff, G.

2015-01-01

Summary Objective To understand emergency department (ED) physicians’ use of electronic documentation in order to identify usability and workflow considerations for the design of future ED information system (EDIS) physician documentation modules. Methods We invited emergency medicine resident physicians to participate in a mixed methods study using task analysis and qualitative interviews. Participants completed a simulated, standardized patient encounter in a medical simulation center while documenting in the test environment of a currently used EDIS. We recorded the time on task, type and sequence of tasks performed by the participants (including tasks performed in parallel). We then conducted semi-structured interviews with each participant. We analyzed these qualitative data using the constant comparative method to generate themes. Results Eight resident physicians participated. The simulation session averaged 17 minutes and participants spent 11 minutes on average on tasks that included electronic documentation. Participants performed tasks in parallel, such as history taking and electronic documentation. Five of the 8 participants performed a similar workflow sequence during the first part of the session while the remaining three used different workflows. Three themes characterize electronic documentation: (1) physicians report that location and timing of documentation varies based on patient acuity and workload, (2) physicians report a need for features that support improved efficiency; and (3) physicians like viewing available patient data but struggle with integration of the EDIS with other information sources. Conclusion We confirmed that physicians spend much of their time on documentation (65%) during an ED patient visit. Further, we found that resident physicians did not all use the same workflow and approach even when presented with an identical standardized patient scenario. Future EHR design should consider these varied workflows while trying to optimize efficiency, such as improving integration of clinical data. These findings should be tested quantitatively in a larger, representative study. PMID:25848411

Geometrical effects on the electron residence time in semiconductor nano-particles.

PubMed

Koochi, Hakimeh; Ebrahimi, Fatemeh

2014-09-07

We have used random walk (RW) numerical simulations to investigate the influence of the geometry on the statistics of the electron residence time τ(r) in a trap-limited diffusion process through semiconductor nano-particles. This is an important parameter in coarse-grained modeling of charge carrier transport in nano-structured semiconductor films. The traps have been distributed randomly on the surface (r(2) model) or through the whole particle (r(3) model) with a specified density. The trap energies have been taken from an exponential distribution and the traps release time is assumed to be a stochastic variable. We have carried out (RW) simulations to study the effect of coordination number, the spatial arrangement of the neighbors and the size of nano-particles on the statistics of τ(r). It has been observed that by increasing the coordination number n, the average value of electron residence time, τ̅(r) rapidly decreases to an asymptotic value. For a fixed coordination number n, the electron's mean residence time does not depend on the neighbors' spatial arrangement. In other words, τ̅(r) is a porosity-dependence, local parameter which generally varies remarkably from site to site, unless we are dealing with highly ordered structures. We have also examined the effect of nano-particle size d on the statistical behavior of τ̅(r). Our simulations indicate that for volume distribution of traps, τ̅(r) scales as d(2). For a surface distribution of traps τ(r) increases almost linearly with d. This leads to the prediction of a linear dependence of the diffusion coefficient D on the particle size d in ordered structures or random structures above the critical concentration which is in accordance with experimental observations.

Dietary intake of PBDEs of residents at two major electronic waste recycling sites in China.

PubMed

Chan, J K Y; Man, Y B; Wu, S C; Wong, M H

2013-10-01

The dietary intake of polybrominated diphenyl ether (PBDE) of local residents from 2 major electronic waste (e-waste) processing sites (Guiyu, Guangdong Province and Taizhou, Zhejiang Province) in China was investigated. Seventy-four food items were collected from these sites, divided into 9 food groups (freshwater fish, marine fish, shellfish, pork, poultry, chicken offal, egg, vegetables and cereals), and examined for residual PBDE concentrations. Out of all food items examined, the freshwater bighead carp (Aristichthys nobilis) contained extremely high (11,400±254 ng/g wet wt.) concentrations of PBDE, the highest concentrations amongst published data concerning PBDE detected in freshwater fish. Food consumption data obtained through semi-quantitative food intake questionnaires showed that Guiyu residents had a PBDE dietary intake of 931±772 ng/kg bw/day, of which BDE-47 (584 ng/kg bw/day) exceeded the US EPA's reference dose (100 ng/kg/day). Taizhou (44.7±26.3 ng/kg bw/day) and Lin'an (1.94±0.86 ng/kg bw/day) residents exhibited lower readings. The main dietary source of PBDEs in Guiyu and Taizhou residents was seafood (88-98%) and pork (41%) in Lin'an. The present results indicated that health risks arising from PBDE dietary exposure are of significance in terms of public health and food safety to local residents of e-waste processing sites. Copyright © 2012 Elsevier B.V. All rights reserved.

For beginners in anaesthesia, self-training with an audiovisual checklist improves safety during anaesthesia induction: A prospective, randomised, controlled two-centre study.

PubMed

Beck, Stefanie; Reich, Christian; Krause, Dorothea; Ruhnke, Bjarne; Daubmann, Anne; Weimann, Jörg; Zöllner, Christian; Kubitz, Jens

2018-01-31

Beginners in residency programmes in anaesthesia are challenged because working environment is complex, and they cannot rely on experience to meet challenges. During this early stage, residents need rules and structures to guide their actions and ensure patient safety. We investigated whether self-training with an electronic audiovisual checklist app on a mobile phone would produce a long-term improvement in the safety-relevant actions during induction of general anaesthesia. During the first month of their anaesthesia residency, we randomised 26 residents to the intervention and control groups. The study was performed between August 2013 and December 2014 in two university hospitals in Germany. In addition to normal training, the residents of the intervention group trained themselves on well tolerated induction using the electronic checklist for at least 60 consecutive general anaesthesia inductions. After an initial learning phase, all residents were observed during one induction of general anaesthesia. The primary outcome was the number of safety items completed during this anaesthesia induction. Secondary outcomes were similar observations 4 and 8 weeks later. Immediately, and 4 weeks after the first learning phase, residents in the intervention group completed a significantly greater number of safety checks than residents in the control group 2.8 [95% confidence interval (CI) 0.4 to 5.1, P = 0.021, Cohen's d = 0.47] and 3.7 (95% CI 1.3 to 6.1, P = 0.003, Cohen's d = 0.61), respectively. The difference between the groups had disappeared by 8 weeks: mean difference in the number of safety checks at 8 weeks was 0.4, 95% CI -2.0 to 2.8, P = 0.736, Cohen's d = 0.07). The use of an audiovisual self-training checklists improves safety-relevant behaviour in the early stages of a residency training programme in anaesthesia.

Survey of the Importance of Professional Behaviors among Medical Students, Residents, and Attending Physicians

ERIC Educational Resources Information Center

Morreale, Mary K.; Balon, Richard; Arfken, Cynthia L.

2011-01-01

Objective: The authors compared the importance of items related to professional behavior among medical students rotating through their psychiatry clerkship, psychiatry residents, and attending psychiatrists. Method: The authors sent an electronic survey with 43 items (rated on the scale 1: Not at All Important; to 5: Very Important) to medical…

Direct Evidence for Delocalization of Charge Carriers at the Fermi Level in a Doped Conducting Polymer

NASA Astrophysics Data System (ADS)

Zhuo, Jing-Mei; Zhao, Li-Hong; Chia, Perq-Jon; Sim, Wee-Sun; Friend, Richard H.; Ho, Peter K. H.

2008-05-01

The infrared absorption spectrum of the polaron charges at the Fermi level EF in a heavily p-doped conducting poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) film has been measured using interferogram-modulated Fourier-transform charge-modulation spectroscopy. The spectrum indicates softer phonons and weaker electron-phonon coupling riding on a strongly redshifted Drude-like electronic transition, different from the population-averaged “bulk” spectrum. This provides direct evidence that the EF holes are sufficiently delocalized even in such disordered materials to reside in an energy continuum (band states) while the rest of the hole population resides in self-localized gap states.

Teaching "global mental health": psychiatry residency directors' attitudes and practices regarding international opportunities for psychiatry residents.

PubMed

Belkin, Gary S; Yusim, Anna; Anbarasan, Deepti; Bernstein, Carol Ann

2011-11-01

The authors surveyed Psychiatry Residency Training Directors' (RTDs') attitudes about the role and feasibility of international rotations during residency training. A 21-question survey was electronically distributed that explored RTDs' beliefs about the value, use, and availability of international clinical and research experiences during residency. Of 171 RTDs, 59 (34.5%) completed the survey; 83% of respondents rated the importance of global mental health education as 3-or-above on a scale of 1 (least important) to 5 (most important), but only 42% indicated that such opportunities were made available. The value of such opportunities was thought to lie primarily in professional development and cultural exposure, less so for enhancing core knowledge competencies. Obstacles to such opportunities included lack of accreditation, financial resources, and faculty/administrative support and supervision. RTD respondents endorsed the value of international experiences during residency, but their availability and educational impact are not fully supported.

Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production

NASA Astrophysics Data System (ADS)

Palaniappan, Ramasamy

Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia electrolysis. PAA-K allowed for a wider operating potential for the electrolytic cell while increasing the rate for HER at lower cell voltages. The conversion of ammonia improved from 16 % to 25 %, while the current efficiency for the consumption of ammonia increased from 92 +/- 1 % to 97 +/- 2 % by using PAA-K in lieu of KOH. The use of PAA-K also prevented the crossover of the hydrogen produced to the anode side, unlike aqueous KOH.

Education Research: Neurology resident education

PubMed Central

Mayans, David; Schneider, Logan; Adams, Nellie; Khawaja, Ayaz M.; Engstrom, John

2016-01-01

Objective: To survey US-trained graduating neurology residents who are American Academy of Neurology members, in an effort to trend perceived quality and completeness of graduate neurology education. Methods: An electronic survey was sent to all American Academy of Neurology members graduating from US neurology residency programs in the Spring of 2014. Results: Of 805 eligible respondents, 24% completed the survey. Ninety-three percent of adult neurology residents and 56% of child neurology residents reported plans to pursue fellowship training after residency. Respondents reported a desire for additional training in neurocritical care, neuro-oncology, neuromuscular diseases, botulinum toxin injection, and nerve blocks. There remains a clear deficit in business training of neurology residents, although there was notable improvement in knowledge of coding and office management compared to previous surveys. Discussion: Although there are still areas of perceived weakness in neurology training, graduating neurology residents feel generally well prepared for their chosen careers. However, most still pursue fellowship training for reasons that are little understood. In addition to certain subspecialties and procedures, practice management remains deficient in neurology training and is a point of future insecurity for most residents. Future curriculum changes should consider resident-reported gaps in knowledge, with careful consideration of improving business training. PMID:26976522

Chiral Redox-Active Isosceles Triangles

DOE PAGES

Nalluri, Siva Krishna Mohan; Liu, Zhichang; Wu, Yilei; ...

2016-04-12

Designing small-molecule organic redox-active materials, with potential applications in energy storage, has received considerable interest of late. Herein, we report on the synthesis, characterization, and application of two rigid chiral triangles, each of which consist of non-identical pyromellitic diimide (PMDI) and naphthalene diimide (NDI)-based redox-active units. 1H and 13C NMR spectroscopic investigations in solution confirm the lower symmetry (C2 point group) associated with these two isosceles triangles. Single-crystal X-ray diffraction analyses reveal their rigid triangular prism-like geometries. Unlike previously investigated equilateral triangle containing three identical NDI subunits, both isosceles triangles do not choose to form one-dimensional supramolecular nanotubes by dintmore » of [C–H···O] interaction-driven columnar stacking. The rigid isosceles triangle, composed of one NDI and two PMDI subunits, forms—in the presence of N,N-dimethylformamide—two different types of intermolecular NDI–NDI and NDI–PMDI π–π stacked dimers with opposite helicities in the solid state. Cyclic voltammetry reveals that both isosceles triangles can accept reversibly up to six electrons. Continuous-wave electron paramagnetic resonance and electron–nuclear double-resonance spectroscopic investigations, supported by density functional theory calculations, on the single-electron reduced radical anions of the isosceles triangles confirm the selective sharing of unpaired electrons among adjacent redox-active NDI subunit(s) within both molecules. The isosceles triangles have been employed as electrode-active materials in organic rechargeable lithium-ion batteries. The evaluation of the structure–performance relationships of this series of diimide-based triangles reveals that the increase in the number of NDI subunits, replacing PMDI ones, within the molecules improves the electrochemical cell performance of the batteries.« less

Organozinc Precursor-Derived Crystalline ZnO Nanoparticles: Synthesis, Characterization and Their Spectroscopic Properties.

PubMed

Liang, Yucang; Wicker, Susanne; Wang, Xiao; Erichsen, Egil Severin; Fu, Feng

2018-01-04

Crystalline ZnO -ROH and ZnO -OR (R = Me, Et, i Pr, n Bu) nanoparticles (NPs) have been successfully synthesized by the thermal decomposition of in-situ-formed organozinc complexes Zn(OR)₂ deriving from the reaction of Zn[N(SiMe₃)₂]₂ with ROH and of the freshly prepared Zn(OR)₂ under an identical condition, respectively. With increasing carbon chain length of alkyl alcohol, the thermal decomposition temperature and dispersibility of in-situ-formed intermediate zinc alkoxides in oleylamine markedly influenced the particle sizes of ZnO -ROH and its shape (sphere, plate-like aggregations), while a strong diffraction peak-broadening effect is observed with decreasing particle size. For ZnO -OR NPs, different particle sizes and various morphologies (hollow sphere or cuboid-like rod, solid sphere) are also observed. As a comparison, the calcination of the fresh-prepared Zn(OR)₂ generated ZnO -R NPs possessing the particle sizes of 5.4~34.1 nm. All crystalline ZnO nanoparticles are characterized using X-ray diffraction analysis, electron microscopy and solid-state ¹H and 13 C nuclear magnetic resonance (NMR) spectroscopy. The size effect caused by confinement of electrons' movement and the defect centres caused by unpaired electrons on oxygen vacancies or ionized impurity heteroatoms in the crystal lattices are monitored by UV-visible spectroscopy, electron paramagnetic resonance (EPR) and photoluminescent (PL) spectroscopy, respectively. Based on the types of defects determined by EPR signals and correspondingly defect-induced probably appeared PL peak position compared to actual obtained PL spectra, we find that it is difficult to establish a direct relationship between defect types and PL peak position, revealing the complication of the formation of defect types and photoluminescence properties.

Probing the spin-orbit Mott state in Sr3Ir2O7 by electron doping

NASA Astrophysics Data System (ADS)

Hogan, Thomas C.

Iridium-based members of the Ruddlesden-Popper family of oxide compounds are characterized by a unique combination of energetically comparable effects: crystal-field splitting, spin-orbit coupling, and electron-electron interactions are all present, and the combine to produce a Jeff = 1/2 ground state. In the bilayer member of this series, Sr3Ir2O7, this state manifests as electrically insulating, with unpaired Ir4+ spins aligned along the long axis of the unit cell to produce a G-type antiferromagnet with an ordered moment of 0.36 uB. In this work, this Mott state is destabilized by electron doping via La3+ substitution on the Sr-site to produce (Sr1-x Lax)3Ir2O7. The introduction of carriers initially causes nano-scale phase-separated regions to develop before driving a global insulator-to-metal transition at x=0.04. Coinciding with this transition is the disappearance of evidence of magnetic order in the system in either bulk magnetization or magnetic scattering experiments. The doping also enhances a structural order parameter observed in the parent compound at forbidden reciprocal lattice vectors. A more complete structural solution is proposed to account for this previously unresolved distortion, and also offers an explanation as to the anomalous net ferromagnetism seen prior in bulk measurements. Finally, spin dynamics are probed via a resonant x-ray technique to reveal evidence of spin-dimer-like behavior dominated by inter-plane interactions. This result supports a bond-operator treatment of the interaction Hamiltonian, and also explains the doping dependence of high temperature magnetic susceptibility.

Characterisation of [Cu4S], the catalytic site in nitrous oxide reductase, by EPR spectroscopy.

PubMed

Oganesyan, Vasily S; Rasmussen, Tim; Fairhurst, Shirley; Thomson, Andrew J

2004-04-07

The enzyme nitrous oxide reductase (N(2)OR) has a unique tetranuclear copper centre [Cu(4)S], called Cu(Z), at the catalytic site for the two-electron reduction of N(2)O to N(2). The X- and Q-band EPR spectra have been recorded from two forms of the catalytic site of the enzyme N(2)OR from Paracoccus pantotrophus, namely, a form prepared anaerobically, Cu(Z), that undergoes a one-electron redox cycle and Cu(Z)*, prepared aerobically, which cannot be redox cycled. The spectra of both species are axial with that of Cu(Z) showing a rich hyperfine splitting in the g||-region at X-band. DFT calculations were performed to gain insight into the electronic configuration and ground-state properties of Cu(Z) and to calculate EPR parameters. The results for the oxidation state [Cu(+1)(3)Cu(+2)(1)S](3+) are in good agreement with values obtained from the fitting of experimental spectra, confirming the absolute oxidation state of Cu(Z). The unpaired spin density in this configuration is delocalised over four copper ions, thus, Cu(I) 20.1%, Cu(II) 9.5%, Cu(III) 4.8% and Cu(IV) 9.2%, the mu(4)-sulfide ion and oxygen ligand. The three copper ions carrying the highest spin density plus the sulfide ion lie approximately in the same plane while the fourth copper ion is perpendicular to this plane and carries only 4.8% spin density. It is suggested that the atoms in this plane represent the catalytic core of Cu(Z), allowing electron redistribution within the plane during interaction with the substrate, N(2)O.

Factors Associated with Medical Knowledge Acquisition During Internal Medicine Residency

PubMed Central

Zeger, Scott L.; Kolars, Joseph C.

2007-01-01

BACKGROUND Knowledge acquisition is a goal of residency and is measurable by in-training exams. Little is known about factors associated with medical knowledge acquisition. OBJECTIVE To examine associations of learning habits on medical knowledge acquisition. DESIGN, PARTICIPANTS Cohort study of all 195 residents who took the Internal Medicine In-Training Examination (IM-ITE) 421 times over 4 years while enrolled in the Internal Medicine Residency, Mayo Clinic, Rochester, MN. MEASUREMENTS Score (percent questions correct) on the IM-ITE adjusted for variables known or hypothesized to be associated with score using a random effects model. RESULTS When adjusting for demographic, training, and prior achievement variables, yearly advancement within residency was associated with an IM-ITE score increase of 5.1% per year (95%CI 4.1%, 6.2%; p < .001). In the year before examination, comparable increases in IM-ITE score were associated with attendance at two curricular conferences per week, score increase of 3.9% (95%CI 2.1%, 5.7%; p < .001), or self-directed reading of an electronic knowledge resource 20 minutes each day, score increase of 4.5% (95%CI 1.2%, 7.8%; p = .008). Other factors significantly associated with IM-ITE performance included: age at start of residency, score decrease per year of increasing age, −0.2% (95%CI −0.36%, −0.042%; p = .01), and graduation from a US medical school, score decrease compared to international medical school graduation, −3.4% (95%CI −6.5%, −0.36%; p = .03). CONCLUSIONS Conference attendance and self-directed reading of an electronic knowledge resource had statistically and educationally significant independent associations with knowledge acquisition that were comparable to the benefit of a year in residency training. PMID:17468889

ELECTRON GUN

DOEpatents

Christofilos, N.C.; Ehlers, K.W.

1960-04-01

A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

The effect of providing a USB syllabus on resident reading of landmark articles

PubMed Central

Chahla, Mayy; Eberlein, Michael; Wright, Scott

2010-01-01

Background The acquisition of new knowledge is a primary goal of residency training. Retrieving and retaining influential primary and secondary medical literature can be challenging for house officers. We set out to investigate the effect of a Universal Serial Bus (USB) drive loaded with landmark scientific articles on housestaff education in a pilot study. Methods We created a USB syllabus that contains 187 primary scientific research articles. The electronic syllabus had links to the full-text articles and was organized using an html webpage with a table of contents according to medical subspecialties. We performed a prospective cohort study of 53 house officers in the internal medicine residency program who received the USB syllabus. We evaluated the impact of the USB syllabus on resident education with surveys at the beginning and conclusion of the nine-month study period. Results All 50 respondents (100%) reported to have used the USB syllabus. The self-reported number of original articles read each month was higher at the end of the nine-month study period compared to baseline. Housestaff rated original articles as being a more valuable educational resource after the intervention. Conclusions An electronic syllabus with landmark scientific articles placed on a USB drive was widely utilized by housestaff, increased the self-reported reading of original scientific articles and seemed to have positively influenced residents' attitude toward original medical literature. PMID:20165697

[Health and quality of life of medical residents].

PubMed

Lourenção, Luciano Garcia; Moscardini, Airton Camacho; Soler, Zaida Aurora Sperli Geraldes

2010-01-01

This article highlights the relationship between health and quality of life among the resident medical staff. A review was carried out to analyze the content of the relationship under study. Sources for this search were the Virtual Health Library (VHL), by BIREME (Centro Latino-American and Caribbean Center on Health Sciences Information), the Electronic databases Medline (Medical Literature Analysis and Retrieval System On-Line) Lilacs (Literatura Latino-American and Caribbean Health Sciences), SciELO (Scientific Electronic Library Online) and the email address scholar.google.com.br. Descriptors used were: Quality of life, Burnout, Internship and Residency. Planning and analysis of scientific literature, was performed to evaluate and discuss issues presented in the studies related to the subject, considering the distribution of publications according to country of origin, date of publication, source and title, focus of study and main conclusions. Studies published point to high rates of burnout, stress, depression, fatigue and insomnia among medical residents; moreover a lack of coping strategies, the relationship between workload and quality of life, require a change of medical legislation regarding work-based learning. Studies have shown that an adequate training program is needed not only to increase professional qualification and personal quality of life, but also to provide safety during patient treatment. It is known that residency training is stressful; it is nevertheless a process required to prepare for a solid career and personal growth of the young medical staff.

Mentorship Programs in Radiation Oncology Residency Training Programs: A Critical Unmet Need

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

Dhami, Gurleen; Gao, Wendy; Gensheimer, Michael F.

Purpose: To conduct a nationwide survey to evaluate the current status of resident mentorship in radiation oncology. Methods and Materials: An anonymous electronic questionnaire was sent to all residents and recent graduates at US Accreditation Council for Graduate Medical Education–accredited radiation oncology residency programs, identified in the member directory of the Association of Residents in Radiation Oncology. Factors predictive of having a mentor and satisfaction with the mentorship experience were identified using univariate and multivariate analyses. Results: The survey response rate was 25%, with 85% of respondents reporting that mentorship plays a critical role in residency training, whereas only 53%more » had a current mentor. Larger programs (≥10 faculty, P=.004; and ≥10 residents, P<.001) were more likely to offer a formal mentorship program, which makes it more likely for residents to have an active mentor (88% vs 44%). Residents in a formal mentoring program reported being more satisfied with the overall mentorship experience (univariate odds ratio 8.77, P<.001; multivariate odds ratio 5, P<.001). On multivariate analysis, women were less likely to be satisfied with the mentorship experience. Conclusions: This is the first survey focusing on the status of residency mentorship in radiation oncology. Our survey highlights the unmet need for mentorship in residency programs.« less

Template for success: using a resident-designed sign-out template in the handover of patient care.

PubMed

Clark, Clancy J; Sindell, Sarah L; Koehler, Richard P

2011-01-01

Report our implementation of a standardized handover process in a general surgery residency program. The standardized handover process, sign-out template, method of implementation, and continuous quality improvement process were designed by general surgery residents with support of faculty and senior hospital administration using standard work principles and business models of the Virginia Mason Production System and the Toyota Production System. Nonprofit, tertiary referral teaching hospital. General surgery residents, residency faculty, patient care providers, and hospital administration. After instruction in quality improvement initiatives, a team of general surgery residents designed a sign-out process using an electronic template and standard procedures. The initial implementation phase resulted in 73% compliance. Using resident-driven continuous quality improvement processes, real-time feedback enabled residents to modify and improve this process, eventually attaining 100% compliance and acceptance by residents. The creation of a standardized template and protocol for patient handovers might eliminate communication failures. Encouraging residents to participate in this process can establish the groundwork for successful implementation of a standardized handover process. Integrating a continuous quality-improvement process into such an initiative can promote active participation of busy general surgery residents and lead to successful implementation of standard procedures. Copyright © 2011 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Using a Learning Coach to Develop Family Medicine Residents' Goal-Setting and Reflection Skills

PubMed Central

George, Paul; Reis, Shmuel; Dobson, Margaret; Nothnagle, Melissa

2013-01-01

Background Self-directed learning (SDL) skills, such as self-reflection and goal setting, facilitate learning throughout a physician's career. Yet, residents do not often formally engage in these activities during residency. Intervention To develop resident SDL skills, we created a learning coach role for a junior faculty member to meet with second-year residents monthly to set learning goals and promote reflection. Methods The study was conducted from 2008–2010 at the Brown Family Medicine Residency in Pawtucket, Rhode Island. During individual monthly meetings with the learning coach, residents entered their learning goals and reflections into an electronic portfolio. A mixed-methods evaluation, including coach's ratings of goal setting and reflection, coach's meeting notes, portfolio entries, and resident interviews, was used to assess progress in residents' SDL abilities. Results Coach ratings of 25 residents' goal-setting ability increased from a mean of 1.9 to 4.6 (P < .001); ratings of reflective capacity increased from a mean of 2.0 to 4.7 (P < .001) during each year. Resident portfolio entries showed a range of domains for goal setting and reflection. Resident interviews demonstrated progressive independence in setting goals and appreciation of the value of reflection for personal development. Conclusions Introducing a learning coach, use of a portfolio, and providing protected time for self-reflected learning allowed residents to develop SDL skills at their own pace. The learning coach model may be applicable to other residency programs in developing resident lifelong learning skills. PMID:24404275

Range use and movements of California condors

USGS Publications Warehouse

Meretsky, V.J.; Snyder, N.F.R.

1992-01-01

Between 1982 and 1987, photographic and telemetric tracking of California Condors (Gymnogyps californianus) yielded information on use of the last known range of the species by 23 individual birds. Except for yearlings, most and possibly all individuals in the population used all major foraging zones. Use of the foraging zones was not uniform among individuals, however. Breeding pairs tended to forage most frequently in zones close to their nests (usually within 70 km, occasionally as far away as 180 km). Immatures (at least older immatures), unpaired birds, and paired birds that were not breeding foraged more widely. Male and female adults used the foraging range in a similar manner. Although most portions of the foraging range received some condor use throughout the year, use varied seasonally in accord with recent and historical patterns of food availability. Nesting areas were separated from foraging zones and were visited much less freely than foraging zones. Paired birds tended strongly to visit only their own and immediately adjacent nesting areas. Their nesting areas remained stable over the years. Unpaired adults and immatures ranged more widely among nesting areas. Condors were sometimes documented flying more than 200 km and traversing the entire range of the species during a day. Birds were variably social in movements. Pair members tended to stay together during long-distance travels. Immatures and unpaired birds sometimes traveled with other condors but often moved singly. In years when the population still included many breeders, the largest observed aggregations included one-half to two-thirds of the total population. The comparative strengths and weaknesses of photographic and telemetric methods are described for tracking and other research endeavors.

Post-trial dopaminergic modulation of conditioned catalepsy: A single apomorphine induced increase/decrease in dopaminergic activation immediately following a conditioned catalepsy response can reverse/enhance a haloperidol conditioned and sensitized catalepsy response.

PubMed

Oliveira, Lucas Rangel; Dias, Flávia Regina Cruz; Santos, Breno Garone; Silva, Jade Leal Loureiro; Carey, Robert J; Carrera, Marinete Pinheiro

2016-09-15

Haloperidol can induce catalepsy and this drug effect can be conditioned as well as sensitized to contextual cues. We used a paired/unpaired Pavlovian conditioning protocol to establish haloperidol catalepsy conditioned and sensitized responses. Groups of rats were given 10 daily catalepsy tests following administration of vehicle (n=24) or haloperidol (1.0mg/kg) either paired (n=18) or unpaired (n=18) to testing. Subsequently, testing for conditioning was conducted and conditioning and sensitization of catalepsy were observed selectively in the paired group. Immediately following a second test for catalepsy conditioning, the groups were subdivided into 4 vehicle groups, 3 unpaired haloperidol groups and 3 paired haloperidol groups and were given one of three post-trial treatments (vehicle, 0.05mg/kg or 2.0mg/kg apomorphine). One day later the conditioned catalepsy test 3 was carried out and on the next day, a haloperidol challenge test was performed. The post-trial apomorphine treatments had major effects on the paired groups upon both conditioning and the haloperidol challenge test. The low dose apomorphine post-trial treatment enhanced both the conditioned and the haloperidol sensitized catalepsy responses. The high dose apomorphine post-trial treatment eliminated conditioned catalepsy and eliminated the initial acute catalepsy response to haloperidol that was induced in the vehicle control groups. These results demonstrate the sensitivity of conditioned drug cues to modification by increases/decreases in activity of the dopamine system in the immediate post-trial interval after a conditioning trial. This demonstration that post-trial dopaminergic drug treatments can modify conditioned drug behavior has broad implications for conditioned drug effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Empirical advances with text mining of electronic health records.

PubMed

Delespierre, T; Denormandie, P; Bar-Hen, A; Josseran, L

2017-08-22

Korian is a private group specializing in medical accommodations for elderly and dependent people. A professional data warehouse (DWH) established in 2010 hosts all of the residents' data. Inside this information system (IS), clinical narratives (CNs) were used only by medical staff as a residents' care linking tool. The objective of this study was to show that, through qualitative and quantitative textual analysis of a relatively small physiotherapy and well-defined CN sample, it was possible to build a physiotherapy corpus and, through this process, generate a new body of knowledge by adding relevant information to describe the residents' care and lives. Meaningful words were extracted through Standard Query Language (SQL) with the LIKE function and wildcards to perform pattern matching, followed by text mining and a word cloud using R® packages. Another step involved principal components and multiple correspondence analyses, plus clustering on the same residents' sample as well as on other health data using a health model measuring the residents' care level needs. By combining these techniques, physiotherapy treatments could be characterized by a list of constructed keywords, and the residents' health characteristics were built. Feeding defects or health outlier groups could be detected, physiotherapy residents' data and their health data were matched, and differences in health situations showed qualitative and quantitative differences in physiotherapy narratives. This textual experiment using a textual process in two stages showed that text mining and data mining techniques provide convenient tools to improve residents' health and quality of care by adding new, simple, useable data to the electronic health record (EHR). When used with a normalized physiotherapy problem list, text mining through information extraction (IE), named entity recognition (NER) and data mining (DM) can provide a real advantage to describe health care, adding new medical material and helping to integrate the EHR system into the health staff work environment.

Alpha-cluster preformation factor within cluster-formation model for odd-A and odd-odd heavy nuclei

NASA Astrophysics Data System (ADS)

Saleh Ahmed, Saad M.

2017-06-01

The alpha-cluster probability that represents the preformation of alpha particle in alpha-decay nuclei was determined for high-intensity alpha-decay mode odd-A and odd-odd heavy nuclei, 82 < Z < 114, 111 < N < 174. This probability was calculated using the energy-dependent formula derived from the formulation of clusterisation states representation (CSR) and the hypothesised cluster-formation model (CFM) as in our previous work. Our previous successful determination of phenomenological values of alpha-cluster preformation factors for even-even nuclei motivated us to expand the work to cover other types of nuclei. The formation energy of interior alpha cluster needed to be derived for the different nuclear systems with considering the unpaired-nucleon effect. The results showed the phenomenological value of alpha preformation probability and reflected the unpaired nucleon effect and the magic and sub-magic effects in nuclei. These results and their analyses presented are very useful for future work concerning the calculation of the alpha decay constants and the progress of its theory.

Fulde-Ferrell-Larkin-Ovchinnikov correlation and free fluids in the one-dimensional attractive Hubbard model

NASA Astrophysics Data System (ADS)

Cheng, Song; Yu, Yi-Cong; Batchelor, M. T.; Guan, Xi-Wen

2018-03-01

In this Rapid Communication, we show that low-energy macroscopic properties of the one-dimensional (1D) attractive Hubbard model exhibit two fluids of bound pairs and of unpaired fermions. Using the thermodynamic Bethe ansatz equations of the model, we first determine the low-temperature phase diagram and analytically calculate the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing correlation function for the partially polarized phase. We then show that for such an FFLO-like state in the low-density regime the effective chemical potentials of bound pairs and unpaired fermions behave like two free fluids. Consequently, the susceptibility, compressibility, and specific heat obey simple additivity rules, indicating the "free" particle nature of interacting fermions on a 1D lattice. In contrast to the continuum Fermi gases, the correlation critical exponents and thermodynamics of the attractive Hubbard model essentially depend on two lattice interacting parameters. Finally, we study scaling functions, the Wilson ratio and susceptibility, which provide universal macroscopic properties and dimensionless constants of interacting fermions at low energy.

Common toads (Bufo arenarum) learn to anticipate and avoid hypertonic saline solutions.

PubMed

Daneri, M Florencia; Papini, Mauricio R; Muzio, Rubén N

2007-11-01

Toads (Bufo arenarum) were exposed to pairings between immersion in a neutral saline solution (i.e., one that caused no significant variation in fluid balance), followed by immersion in a highly hypertonic saline solution (i.e., one that caused water loss). In Experiment 1, solutions were presented in a Pavlovian conditioning arrangement. A group receiving a single neutral-highly hypertonic pairing per day exhibited a greater conditioned increase in heart rate than groups receiving either the same solutions in an explicitly unpaired fashion, or just the neutral solution. Paired toads also showed a greater ability to compensate for water loss across trials than that of the explicitly unpaired group. Using the same reinforcers and a similar apparatus, Experiment 2 demonstrated that toads learn a one-way avoidance response motivated by immersion in the highly hypertonic solution. Cardiac and avoidance conditioning are elements of an adaptive system for confronting aversive situations involving loss of water balance. Copyright 2007 APA.

Conformational Heterogeneity in a Fully Complementary DNA Three-Way Junction with a GC-Rich Branchpoint.

PubMed

Toulmin, Anita; Baltierra-Jasso, Laura E; Morten, Michael J; Sabir, Tara; McGlynn, Peter; Schröder, Gunnar F; Smith, Brian O; Magennis, Steven W

2017-09-19

DNA three-way junctions (3WJs) are branched structures that serve as important biological intermediates and as components in DNA nanostructures. We recently derived the global structure of a fully complementary 3WJ and found that it contained unpaired bases at the branchpoint, which is consistent with previous observations of branch flexibility and branchpoint reactivity. By combining high-resolution single-molecule Förster resonance energy transfer, molecular modeling, time-resolved ensemble fluorescence spectroscopy, and the first 19 F nuclear magnetic resonance observations of fully complementary 3WJs, we now show that the 3WJ structure can adopt multiple distinct conformations depending upon the sequence at the branchpoint. A 3WJ with a GC-rich branchpoint adopts an open conformation with unpaired bases at the branch and at least one additional conformation with an increased number of base interactions at the branchpoint. This structural diversity has implications for branch interactions and processing in vivo and for technological applications.

The Drosophila cytokine Unpaired 2 regulates physiological homeostasis by remotely controlling Insulin secretion

PubMed Central

Rajan, Akhila; Perrimon, Norbert

2012-01-01

In Drosophila the fat body (FB), a functional analog of the vertebrate adipose tissue, is the 'nutrient sensor' that conveys the nutrient status to the insulin producing cells (IPCs) in the fly brain to release insulin-like peptides (Dilps). Dilp secretion in turn regulates energy balance and promotes systemic growth. We identify Unpaired2 (Upd2), a protein with similarities to type I cytokines, as a secreted factor produced by the FB in the ‘fed’ state. When upd2 function is perturbed specifically in the FB, it results in a systemic reduction in growth and alters energy metabolism. Upd2 activates JAK/STAT signaling in a population of GABAergic neurons that project onto the IPCs. This activation relieves the inhibitory tone of the GABAergic neurons on the IPCs, resulting in the secretion of Dilps. Strikingly, we find that human Leptin, can rescue the upd2 mutant phenotypes, suggesting that Upd2 is the functional homolog of Leptin. PMID:23021220

Perceived Barriers to Information Access Among Medical Residents in Iran: Obstacles to Answering Clinical Queries in Settings with Limited Internet Accessibility

PubMed Central

Mazloomdoost, Danesh; Mehregan, Shervineh; Mahmoudi, Hilda; Soltani, Akbar; Embi, Peter J.

2007-01-01

Studies performed in the US and other Western countries have documented that physicians generate many clinical questions during a typical day and rely on various information sources for answers. Little is known about the information seeking behaviors of physicians practicing in other countries, particularly those with limited Internet connectivity. We conducted this study to document the perceived barriers to information resources used by medical residents in Iran. Our findings reveal that different perceived barriers exist for electronic versus paper-based resources. Notably, paper-based resources are perceived to be limited by resident time-constraints and availability of resources, whereas electronic resources are limited by cost decentralized resources (such as PDAs) and accessibility of centralized, Internet access. These findings add to the limited literature regarding health information-seeking activities in international healthcare settings, particularly those with limited Internet connectivity, and will supplement future studies of and interventions in such settings. PMID:18693891

Perceived barriers to information access among medical residents in Iran: obstacles to answering clinical queries in settings with limited Internet accessibility.

PubMed

Mazloomdoost, Danesh; Mehregan, Shervineh; Mahmoudi, Hilda; Soltani, Akbar; Embi, Peter J

2007-10-11

Studies performed in the US and other Western countries have documented that physicians generate many clinical questions during a typical day and rely on various information sources for answers. Little is known about the information seeking behaviors of physicians practicing in other countries, particularly those with limited Internet connectivity. We conducted this study to document the perceived barriers to information resources used by medical residents in Iran. Our findings reveal that different perceived barriers exist for electronic versus paper-based resources. Notably, paper-based resources are perceived to be limited by resident time-constraints and availability of resources, whereas electronic resources are limited by cost decentralized resources (such as PDAs) and accessibility of centralized, Internet access. These findings add to the limited literature regarding health information-seeking activities in international healthcare settings, particularly those with limited Internet connectivity, and will supplement future studies of and interventions in such settings.

Flow Synthesis of Diaryliodonium Triflates

PubMed Central

2017-01-01

A safe and scalable synthesis of diaryliodonium triflates was achieved using a practical continuous-flow design. A wide array of electron-rich to electron-deficient arenes could readily be transformed to their respective diaryliodonium salts on a gram scale, with residence times varying from 2 to 60 s (44 examples). PMID:28695736

Administrative organization in diagnostic radiology residency program leadership.

PubMed

Webber, Grant R; Mullins, Mark E; Chen, Zhengjia; Meltzer, Carolyn C

2012-04-01

The aim of this study was to document the current state of administrative structure in US diagnostic radiology (DR) residency program leadership. A secondary objective was to assess for correlation(s), if any, with DR residency programs that equipped positions such as assistant, associate, and emeritus program director (PD) with respect to residency size and region of the country. The Fellowship and Residency Electronic Interactive Database, as well as direct communication and programmatic Web site searches, were used to gather data regarding current US DR residency leadership. Data collected included the presence of additional leadership titles, including assistant PD, associate PD, and PD emeritus, and how many faculty members currently held each position. Programs were excluded if results could not be identified. Analysis of variance and t tests were used to estimate the correlations of the size of a residency with having additional or shared PD positions and the types of positions, respectively. Chi-square tests were used to assess for any regional differences. As of the time of this project, the Fellowship and Residency Electronic Interactive Database defined 186 US DR residency programs. A total of 173 programs (93%) were included in the analysis; the remainder were excluded because of unavailability of relevant data. Seventy-two percent (124 of 173) of programs had additional DR leadership positions. Of these, 30 programs (17%) had more than one such position. There were no significant differences in the sizes of the programs that used these additional positions (mean, 25 ± 12; range, 6-72) compared with those that did not (mean, 24 ± 12; range, 7-51). There were no significant differences between programs that had additional positions with respect to region of the country. The majority of US DR residency programs used some form of additional DR leadership position. In the majority of cases, this was in the form of an assistant or associate PD. Nearly one-fifth of programs studied had more than one such position. This is a positive model for the depth and breadth of management of US residency programs, serving both as a template for matrixed leadership and as a source of leadership succession planning. Copyright © 2012 American College of Radiology. Published by Elsevier Inc. All rights reserved.

The urology residency matching program in practice.

PubMed

Teichman, J M; Anderson, K D; Dorough, M M; Stein, C R; Optenberg, S A; Thompson, I M

2000-06-01

We evaluate behaviors and attitudes among resident applicants and program directors related to the American Urological Association (AUA) residency matching program and recommend changes to improve the match. Written questionnaires were mailed to 519 resident applicants and 112 program directors after the 1999 American Urological Association match. Subjects were asked about their observations, behaviors and opinions towards the match. Questionnaires were returned by 230 resident applicants and 94 program directors (44% and 83% response rates, respectively.) Of the resident applicants 75% spent $1,001 to $5,000 for interviewing. Of the program directors 47% recalled that applicants asked how programs would rank the applicant and 61% of applicants recalled that program directors asked applicants how they would rank programs. Dishonesty was acknowledged by 31% of program directors and 44% of resident applicants. Of program directors 82% thought applicants "lied", while 67% of applicants thought that programs "lied" (quotations indicate questionnaire language). Participants characterized their own dishonesty as "just playing the game" or they "did not feel badly." Of program directors 81% and of applicants 61% were "skeptical" or "did not believe" when informed they were a "high" or "number 1" selection. Being asked about marital status was recalled by 91% of male and 100% of female (p = 0. 02), if they had children by 53% of male and 67% of female, (p = 0. 03), and intent to have children by 25% of male and 62% of female (p <0.001), applicants, respectively. Free-form comments were written by 132 resident applicants and 28 program directors. The most frequent comments suggested the need to improve ethical behavior, modify the process so applications could be transmitted electronically and modify interviews to reduce applicant financial burden. Nine female applicants commented on their perceptions of sexual discrimination during the interviews. Resident applicants and program directors violate match code rules frequently. Program directors and resident applicants are skeptical of each other. Patterns of faculty behavior differ based on applicant gender. Interviews are costly for applicants. We recommend that 1) programs adopt policies to enhance fairness, 2) applications be filed electronically, 3) programs assist resident applicants with interview accommodation to reduce financial burden and 4) a post-interview code of limited or noncommunication be adopted.

Education Research: Neurology resident education: Trending skills, confidence, and professional preparation.

PubMed

Jordan, Justin T; Mayans, David; Schneider, Logan; Adams, Nellie; Khawaja, Ayaz M; Engstrom, John

2016-03-15

To survey US-trained graduating neurology residents who are American Academy of Neurology members, in an effort to trend perceived quality and completeness of graduate neurology education. An electronic survey was sent to all American Academy of Neurology members graduating from US neurology residency programs in the Spring of 2014. Of 805 eligible respondents, 24% completed the survey. Ninety-three percent of adult neurology residents and 56% of child neurology residents reported plans to pursue fellowship training after residency. Respondents reported a desire for additional training in neurocritical care, neuro-oncology, neuromuscular diseases, botulinum toxin injection, and nerve blocks. There remains a clear deficit in business training of neurology residents, although there was notable improvement in knowledge of coding and office management compared to previous surveys. Although there are still areas of perceived weakness in neurology training, graduating neurology residents feel generally well prepared for their chosen careers. However, most still pursue fellowship training for reasons that are little understood. In addition to certain subspecialties and procedures, practice management remains deficient in neurology training and is a point of future insecurity for most residents. Future curriculum changes should consider resident-reported gaps in knowledge, with careful consideration of improving business training. © 2016 American Academy of Neurology.

Ultrastructure and Pathology of Microsporidium phytoseiuli n. sp. Infecting the Predatory Mite, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)

PubMed

Bjørnson; Steiner; Keddie

1996-11-01

Ultrastructure and pathology of Microsporidium phytoseiuli n. sp. infecting the predatory mite Phytoseiulus persimilis Athias-Henriot is described using light and transmission electron microscopy. Infected mites showed no gross, external symptoms. All observed stages of the parasite had unpaired nuclei. Schizonts were commonly observed within nuclei of digestive cells of the ventriculus and within the cytoplasm of cells lining the cecal wall and in muscle tissue underlying it. Sporoblasts and spores occurred in the nuclei and cytoplasm of digestive cells within the ventriculus, in cortical regions of the sub- and supraesophageal ganglia, within the cecal wall and muscle tissue, and in parenchyma cells underlying the cuticle. Mature spores were also observed in developing eggs within gravid females. These were broad- to elongate-ovoid, measured 4.33 ± 0.35 x 1.27 ± 0.15 &mgr;m (electron micrographs), 5.37 ± 0.46 x 2.22 ± 0.17 &mgr;m (fixed and stained), and 5.88 ± 0.34 x 2.22 ± 0.19 &mgr;m (fresh) and had an isolfilar polar filament coiled 12 to 15 times within the posterior two-thirds. Within cells, individual spores appeared to be in direct contact with host cytoplasm, while groups of spores were infrequently observed within interfacial envelopes. Groups of 4, 8, to more than 16 spores were observed by light microscopy, while 8 was the maximum observed by electron microscopy. No spores were observed in Tetranychus urticae, a mite used as food during this study.

Cigarette smoking and its association with serum lipid/lipoprotein among Chinese nonagenarians/centenarians

PubMed Central

2012-01-01

Objective Cigarette smoking had been confirmed as an increased risk for dyslipidemia, but none of the evidence was from long-lived population. In present study, we detected relationship between cigarette smoking habits and serum lipid/lipoprotein (serum Triglyceride (TG), Total cholesterol (TC), Low-density lipoprotein (LDL) and high-density lipoprotein (HDL)) among Chinese Nonagenarians/Centenarian. Methods The present study analyzed data from the survey that was conducted on all residents aged 90 years or more in a district, there were 2,311,709 inhabitants in 2005. Unpaired Student’s t test, χ2 test, and multiple logistic regression were used to analyze datas. Results The individuals included in the statistical analysis were 216 men and 445 women. Current smokers had lower level of TC (4.05 ± 0.81 vs. 4.21 ± 0.87, t = 2.403, P = 0.017) and lower prevalence of hypercholesteremia (9.62% vs. 15.13%, χ2 = 3.018,P = 0.049) than nonsmokers. Unadjusted and adjusted multiple logistic regressions showed that cigarette smoking was not associated with risk for abnormal serum lipid/lipoprotein. Conclusions In summary, we found that among Chinese nonagenarians/centenarians, cigarette smoking habits were not associated with increased risk for dyslipidemia, which was different from the association of smoking habits with dyslipidemia in general population. PMID:22828289

Structural features of the DNA hairpin d(ATCCTA-GTTA-TAGGAT): formation of a G-A base pair in the loop.

PubMed Central

van Dongen, M J; Mooren, M M; Willems, E F; van der Marel, G A; van Boom, J H; Wijmenga, S S; Hilbers, C W

1997-01-01

The three-dimensional structure of the hairpin formed by d(ATCCTA-GTTA-TAGGAT) has been determined by means of two-dimensional NMR studies, distance geometry and molecular dynamics calculations. The first and the last residues of the tetraloop of this hairpin form a sheared G-A base pair on top of the six Watson-Crick base pairs in the stem. The glycosidic torsion angles of the guanine and adenine residues in the G-A base pair reside in the anti and high- anti domain ( approximately -60 degrees ) respectively. Several dihedral angles in the loop adopt non-standard values to accommodate this base pair. The first and second residue in the loop are stacked in a more or less normal helical fashion; the fourth loop residue also stacks upon the stem, while the third residue is directed away from the loop region. The loop structure can be classified as a so-called type-I loop, in which the bases at the 5'-end of the loop stack in a continuous fashion. In this situation, loop stability is unlikely to depend heavily on the nature of the unpaired bases in the loop. Moreover, the present study indicates that the influence of the polarity of a closing A.T pair is much less significant than that of a closing C.G base pair. PMID:9092659

Intake of Boron, Cadmium, and Molybdenum enhances rat thyroid cell transformation.

PubMed

Luca, Emilia; Fici, Laura; Ronchi, Anna; Marandino, Ferdinando; Rossi, Esther Diana; Caristo, Maria Emiliana; Malandrino, Pasqualino; Russo, Marco; Pontecorvi, Alfredo; Vigneri, Riccardo; Moretti, Fabiola

2017-06-02

Epidemiologic data in volcanic areas suggest that environmental factors might be involved in the increase of thyroid cancer (TC) incidence. Recent reports indicate that several heavy metals and metalloids are increased in volcanic areas. This study aims to evaluate the combined effect of three of these elements Boron (B), Cadmium (Cd), and Molybdenum (Mo) - all increased in the volcanic area of Mt. Etna, in Italy - on thyroid tumorigenesis in the rat. Female Wistar rats prone to develop thyroid tumors by low-iodine diet and methimazole treatment received ad libitum drinking water supplemented with B, Cd, and Mo at concentrations in the range found in the urine samples of residents of the volcanic area. At 5 and 10 months animals were euthanized, and their thyroid analysed. Statistical analysis was performed with a 2-way unpaired t-test. No toxic effect of the three elements on the growth of the animals was observed. A significant increase of histological features of transformation was observed in thyroid follicular cells of rats treated with B, Cd, and Mo compared with those of control group. These abnormalities were associated with decreased iodine content in the thyroid. This study provides the evidence that slightly increased environmental concentrations of B, Cd, and Mo can accelerate the appearance of transformation marks in the thyroid gland of hypothyroid rats.

Can Medical School Performance Predict Residency Performance? Resident Selection and Predictors of Successful Performance in Obstetrics and Gynecology

PubMed Central

Stohl, Hindi E.; Hueppchen, Nancy A.; Bienstock, Jessica L.

2010-01-01

Background During the evaluation process, Residency Admissions Committees typically gather data on objective and subjective measures of a medical student's performance through the Electronic Residency Application Service, including medical school grades, standardized test scores, research achievements, nonacademic accomplishments, letters of recommendation, the dean's letter, and personal statements. Using these data to identify which medical students are likely to become successful residents in an academic residency program in obstetrics and gynecology is difficult and to date, not well studied. Objective To determine whether objective information in medical students' applications can help predict resident success. Method We performed a retrospective cohort study of all residents who matched into the Johns Hopkins University residency program in obstetrics and gynecology between 1994 and 2004 and entered the program through the National Resident Matching Program as a postgraduate year-1 resident. Residents were independently evaluated by faculty and ranked in 4 groups according to perceived level of success. Applications from residents in the highest and lowest group were abstracted. Groups were compared using the Fisher exact test and the Student t test. Results Seventy-five residents met inclusion criteria and 29 residents were ranked in the highest and lowest quartiles (15 in highest, 14 in lowest). Univariate analysis identified no variables as consistent predictors of resident success. Conclusion In a program designed to train academic obstetrician-gynecologists, objective data from medical students' applications did not correlate with successful resident performance in our obstetrics-gynecology residency program. We need to continue our search for evaluation criteria that can accurately and reliably select the medical students that are best fit for our specialty. PMID:21976076

Pediatric dermatology training during residency: a survey of the 2014 graduating residents.

PubMed

Akhavan, Alaleh; Murphy-Chutorian, Blair; Friedman, Adam

2015-01-01

Knowledge of pediatric dermatology is considered a core competency of dermatology training and should be expected of all practicing dermatologists. While the numbers of both pediatric dermatology fellowships and board certified pediatric dermatologists in the workforce have increased over the years, recent reports suggest that there is a gap in pediatric dermatology education during dermatology residency. The goal of this study is to assess the current state of pediatric education during residency, as well as the clinical experience, satisfaction and expectations of graduating dermatology residents. A 31-question self-report survey was distributed electronically to 294 third-year dermatology residents with questions pertaining to demographics, didactic education, resident experience in pediatric dermatology training, satisfaction with pediatric training and future plans. One hundred and twenty-three residents responded (41.8% response rate) representing approximately 29.1% of the total number of graduating residents. 69 (56.1%) residents reported academic time specifically devoted to pediatric dermatology, the majority (79.7%) of which was led by pediatric dermatologists. 82% of residents reported dedicated pediatric dermatology clinics at their program. 86.8% of respondents felt that their training in pediatric dermatology will allow them to confidently see pediatric dermatology patients in practice. This survey highlights a promising state of pediatric dermatology training among current graduating dermatology residents. The majority of current graduating dermatology residents are satisfied with their pediatric dermatology education, feel confident treating pediatric patients, and plan to see pediatric patients in clinical practice. © 2015 Wiley Periodicals, Inc.

Theoretical studies of damage to 3'-uridine monophosphate induced by electron attachment.

PubMed

Zhang, Ru Bo; Zhang, Ke; Eriksson, Leif A

2008-01-01

Low-energy electrons (LEE) are well known to induce nucleic acid damage. However, the damage mechanisms related to charge state and structural features remain to be explored in detail. In the present work, we have investigated the N1-glycosidic and C3'-O(P) bond ruptures of 3'-UMP (UMP=uridine monophosphate) and the protonated form 3'-UMPH with -1 and zero charge, respectively, based on hybrid density functional theory (DFT) B3 LYP together with the 6-31+G(d,p) basis set. The glycosidic bond breakage reactions of the 3'UMP and 3'UMPH electron adducts are exothermic in both cases, with barrier heights of 19-20 kcal mol(-1) upon inclusion of bulk solvation. The effects of the charge state on the phosphate group are marginal, but the C2'-OH group destabilizes the transition structure of glycosidic bond rupture of 3'-UMPH in the gas phase by approximately 5.0 kcal mol(-1). This is in contrast with the C3'-O(P) bond ruptures induced by LEE in which the charge state on the phosphate influences the barrier heights and reaction energies considerably. The barrier towards C3'-O(P) bond dissociation in the 3'UMP electron adduct is higher in the gas phase than the one corresponding to glycosidic bond rupture and is dramatically influenced by the C2'-OH group and bulk salvation, which decreases the barrier to 14.7 kcal mol(-1). For the C3'-O(P) bond rupture of the 3'UMPH electron adduct, the reaction is exothermic and the barrier is even lower, 8.2 kcal mol(-1), which is in agreement with recent results for 3'-dTMPH and 5'-dTMPH (dTMPH=deoxythymidine monophosphate). Both the Mulliken atomic charges and unpaired-spin distribution play significant roles in the reactions.

Rotation Dynamics Do Not Determine the Unexpected Isotropy of Methyl Radical EPR Spectra.

PubMed

Benetis, Nikolas P; Dmitriev, Yurij; Mocci, Francesca; Laaksonen, Aatto

2015-09-03

A simple first-principles electronic structure computation, further qc (quantum chemistry) computation, of the methyl radical gives three equal hf (hyperfine) couplings for the three protons with the unpaired electron. The corresponding dipolar tensors were notably rhombic and had different orientations and regular magnitude components, as they should, but what the overall A-tensor was seen by the electron spin is a different story! The final g = (2.002993, 2.002993, 2.002231) tensor and the hf coupling results obtained in vacuum, at the B3LYP/EPRIII level of theory clearly indicate that in particular the above A = (-65.19, -65.19, 62.54) MHz tensor was axial to a first approximation without considering any rotational dynamics for the CH3. This approximation was not applicable, however, for the trifluoromethyl CF3 radical, a heavier and nonplanar rotor with very anisotropic hf coupling, used here for comparison. Finally, a derivation is presented explaining why there is actually no need for the CH3 radicals to consider additional rotational dynamics in order for the electron to obtain an axially symmetric hf (hyperfine) tensor by considering the simultaneous dipolar couplings of the three protons. An additional consequence is an almost isotropic A-tensor for the electron spin of the CH3 radical. To the best of our knowledge, this point has not been discussed in the literature before. The unexpected isotropy of the EPR parameters of CH3 was solely attributed to the rotational dynamics and was not clearly separated from the overall symmetry of the species. The present theoretical results allowed a first explanation of the "forbidden" satellite lines in the CH3 EPR spectrum. The satellites are a fingerprint of the radical rotation, helping thus in distinguishing the CH3 reorientation from quantum rotation at very low temperatures.

Elemental, microstructural, and mechanical characterization of high gold orthodontic brackets after intraoral aging.

PubMed

Hersche, Sepp; Sifakakis, Iosif; Zinelis, Spiros; Eliades, Theodore

2017-02-01

The purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Backscattered electron imaging (BEI) was performed, and the elemental composition was determined by X-ray EDS analysis (EDX). After appropriate metallographic preparation, the mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), and Vickers hardness (HV). These properties were determined employing instrumented indentation testing (IIT) with a Vickers indenter. The results were statistically analyzed by unpaired t-test (α=0.05). There were no statistically significant differences evidenced in surface morphology and elemental content between the control and the experimental group. These two groups of brackets showed no statistically significant difference in surface morphology. Moreover, the mean values of HM, EIT, ηIT, and HV did not reach statistical significance between the groups (p>0.05). Under the limitations of this study, it may be concluded that the surface elemental content and microstructure as well as the evaluated mechanical properties of the Incognito™ lingual brackets remain unaffected by intraoral aging.

Electronic structure of trioxide, oxoperoxide, oxosuperoxide, and ozonide clusters of the 3d elements: density functional theory study.

PubMed

Uzunova, Ellie L

2011-03-03

The trioxide clusters with stoichiometry MO3, and the structural isomers with side-on and end-on bonded oxygen atoms, are studied by DFT with the B1LYP functional. For the first half of the 3d elements row (Sc to Cr), pyramidal or distorted pyramidal structures dominate among the trioxide and oxoperoxide ground states, while the remaining elements form planar trioxides, oxoperoxides, oxosuperoxides, and ozonides. Low-lying trioxide clusters are formed by Ti, V, Cr, and Mn, among which the distorted pyramidal VO3 in the (2)A'' state, the pyramidal CrO3 in the (1)A1 state, and the planar MnO3 in the (2)A1' state are global minima. With the exception of the middle-row elements Mn, Fe, and Co, the magnetic moment of the ground-state clusters is formed with a major contribution from unpaired electrons located at the oxygen atoms. The stability of trioxides and oxoperoxides toward release of molecular oxygen is significantly higher for Sc, Ti, and V than for the remaining elements of the row. A trend of increasing the capability to dissociate one oxygen molecule is observed from Cr to Cu, with the exception of OFe(O2) being more reactive than OCo(O2). A gradual increase of reactivity from Ti to Cu is observed for the complete fragmentation reaction M + O + O2.

Theoretical study on magnetism induced by H vacancy in isolated Alq3 and Gaq3 molecules

NASA Astrophysics Data System (ADS)

Ju, Lin; Xu, Tongshuai; Zhang, Yongjia; Sun, Li

2017-10-01

The magnetism induced by H vacancy in isolated Alq3 and Gaq3 molecules has been studied based on density functional theory. The isolated stoichiometric Alq3 and Gaq3 molecules are non-magnetic. With an H vacancy, both Alq3 and Gaq3 molecules could show magnetism, which are mainly due to the polarization of the C 2p electrons and the magnetic moments are mainly distributed at most nearby C atoms of H vacancies. This is because the unpaired electron on the C atom appears, when the H atom nearby is removed. Six cases of the H vacancy introduced in the Alq3 and Gaq3 molecules are considered, respectively. By comparing the relative defect formation energy, the V H3 vacancy is most likely to appear in the two kinds of molecules. In addition, for the ground state configuration of isolated Alq3 and Gaq3 molecules with two H vacancies, the energy of the ferromagnetic state is lower than that of the antiferromagnetic state, which means that the ferromagnetic state is stable. The ferromagnetic mechanism can be explained by the Heisenberg direct exchange interaction between two the polarized C atoms. Our work opens a new way to synthesize organic magnetic materials and perfects the theory of organic ferromagnetism by introducing the d 0 ferromagnetism.

Synthesis, spectral and electrochemical studies of binuclear Ru(III) complexes containing dithiosemicarbazone ligand

NASA Astrophysics Data System (ADS)

Kanchana Devi, A.; Ramesh, R.

2014-01-01

Synthesis of several new octahedral binuclear ruthenium(III) complexes of the general composition [(EPh3)2(X)Ru-L-Ru(X)(EPh3)2] containing benzene dithiosemicarbazone ligands (where E = P or As; X = Cl or Br; L = binucleating ligands) is presented. All the complexes have been fully characterized by elemental analysis, FT-IR, UV-vis and EPR spectroscopy together with magnetic susceptibility measurements. IR study shows that the dithiosemicarbazone ligands behave as dianionic tridentate ligands coordinating through the oxygen atom of the deprotonated phenolic group, nitrogen atom of the azomethine group and thiolate sulphur. In DMF solution, all the complexes exhibit intense d-d transition and ligand-to-metal charge transfer (LMCT) transition in the visible region. The magnetic moment values of the complexes are in the range 1.78-1.82 BM, which reveals the presence of one unpaired electron on each metal ion. The EPR spectra of the liquid samples at LNT show the presence of three different 'g' values (gx ≠ gy ≠ gz) indicate a rhombic distortion around the ruthenium ion. All the complexes exhibit two quasi-reversible one electron oxidation responses (RuIII-RuIII/RuIII-RuIV; RuIII-RuIV/RuIV-RuIV) within the E1/2 range of 0.61-0.74 V and 0.93-0.98 V respectively, versus Ag/AgCl.

Cross sectional survey of ultrasound use for central venous catheter insertion among resident physicians.

PubMed

Nomura, Jason T; Sierzenski, Paul R; Nace, Jason E; Bollinger, Melissa

2008-07-01

Use of ultrasound guidance for Central Venous Catheter insertion has been associated with decreased complications and increased success rates. Previous reports show low rates of use among physicians. Evaluation of the frequency of Ultrasound Guidance use for Central Venous Catheter insertion among residents at a teaching institution. A cross sectional electronic survey of resident physicians at a tertiary care teaching hospital was conducted to evaluate use of Ultrasound Guidance for Central Venous Catheterization. Assessment included self reported frequency of ultrasound guidance use, and volume of central venous catheter placement. Attitudes toward the use of ultrasound were assessed using Likert scales. There is a high rate. over 90%, of ultrasound guidance use for Internal Jugular central venous catheters among residents. The majority of residents use sterile real-time imaging with a single operator with a reported success rate greater then 80%. Resident use of ultrasound guidance for Internal Jugular central venous catheter insertion can be much higher than previously reported in the literature.

Plastic surgery residency graduate outcomes: a 43-year experience at a single institution and the first "integrated" training program in the United States.

PubMed

Noland, Shelley S; Lee, Gordon K

2012-04-01

The Accreditation Council for Graduate Medical Education emphasizes outcome-based residency education. This project is an outcomes study on graduates of the Stanford University Integrated Plastic Surgery Residency. A survey assessing various outcomes, including practice profile, financial, personal, and educational issues, was electronically distributed to all 130 graduates between 1966 and 2009. There was a 65% response rate. Nearly all respondents are currently in practice. Popular fellowships included hand and microsurgery. Most respondents participated in research and held leadership roles. Adequate residency education was noted in areas of patient care, board preparation, and ethical and legal issues. Inadequate residency education was noted in areas of managing a practice, coding, and cost-effective medicine. This is the first long-term outcomes study of plastic surgery graduates. Most are in active, successful practice. We have incorporated educational content related to running a small business, contract negotiating, and marketing to better prepare our residents for future practice.

Self-Trapped Excitons in Ionic-Covalent Silver Halide Crystals and Nanostructures: High-Frequency EPR, ESE, ENDOR and ODMR Studies

PubMed Central

Baranov, P. G.; Poluektov, O. G.; Schmidt, J.

2010-01-01

Silver halides have unique features in solid state physics because their properties are considered to be of borderline nature between ionic and covalent bonding. In AgCl, the self-trapped hole (STH) is centered and partly trapped in the cationic sublattice, forming an Ag2+ ion inside of a (AgCl6)4− complex as a result of the Jahn–Teller distortion. The STH in AgCl can capture an electron from the conduction band forming the self-trapped exciton (STE). Recent results of a study of STE by means of high-frequency electron paramagnetic resonance, electron spin echo, electron–nuclear double resonance (ENDOR) and optically detected magnetic resonance (ODMR) are reviewed. The properties of the STE in AgCl crystals, such as exchange coupling, the ordering of the triplet and singlet sublevels, the dynamical properties of the singlet and triplet states, and the hyperfine interaction with the Ag and Cl (Br) nuclei are discussed. Direct information about the spatial distribution of the wave function of STE unpaired electrons was obtained by ENDOR. From a comparison with the results of an ENDOR study of the shallow electron center and STH, it is concluded that the electron is mainly contained in a hydrogen-like 1s orbital with a Bohr radius of 15.1 ± 0.6 Å, but near its center the electron density reflects the charge distribution of the hole. The hole of the STE is virtually identical to an isolated STH center. For AgCl nanocrystals embedded into the KCl crystalline matrix, the anisotropy of the g-factor of STE and STH was found to be substantially reduced compared with that of bulk AgCl crystals, which can be explained by a considerable suppression of the Jahn–Teller effect in nanoparticles. A study of ODMR in AgBr nanocrystals in KBr revealed spatial confinement effects and allowed estimating the nanocrystal size from the shape of the ODMR spectra. PMID:21151483

Geometrical effects on the electron residence time in semiconductor nano-particles

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

Koochi, Hakimeh; Ebrahimi, Fatemeh, E-mail: f-ebrahimi@birjand.ac.ir; Solar Energy Research Group, University of Birjand, Birjand

2014-09-07

We have used random walk (RW) numerical simulations to investigate the influence of the geometry on the statistics of the electron residence time τ{sub r} in a trap-limited diffusion process through semiconductor nano-particles. This is an important parameter in coarse-grained modeling of charge carrier transport in nano-structured semiconductor films. The traps have been distributed randomly on the surface (r{sup 2} model) or through the whole particle (r{sup 3} model) with a specified density. The trap energies have been taken from an exponential distribution and the traps release time is assumed to be a stochastic variable. We have carried out (RW)more » simulations to study the effect of coordination number, the spatial arrangement of the neighbors and the size of nano-particles on the statistics of τ{sub r}. It has been observed that by increasing the coordination number n, the average value of electron residence time, τ{sup ¯}{sub r} rapidly decreases to an asymptotic value. For a fixed coordination number n, the electron's mean residence time does not depend on the neighbors' spatial arrangement. In other words, τ{sup ¯}{sub r} is a porosity-dependence, local parameter which generally varies remarkably from site to site, unless we are dealing with highly ordered structures. We have also examined the effect of nano-particle size d on the statistical behavior of τ{sup ¯}{sub r}. Our simulations indicate that for volume distribution of traps, τ{sup ¯}{sub r} scales as d{sup 2}. For a surface distribution of traps τ{sup ¯}{sub r} increases almost linearly with d. This leads to the prediction of a linear dependence of the diffusion coefficient D on the particle size d in ordered structures or random structures above the critical concentration which is in accordance with experimental observations.« less

Optical pumping of electron and nuclear spin in a negatively-charged quantum dot

NASA Astrophysics Data System (ADS)

Bracker, Allan; Gershoni, David; Korenev, Vladimir

2005-03-01

We report optical pumping of electron and nuclear spins in an individual negatively-charged quantum dot. With a bias-controlled heterostructure, we inject one electron into the quantum dot. Intense laser excitation produces negative photoluminescence polarization, which is easily erased by the Hanle effect, demonstrating optical pumping of a long-lived resident electron. The electron spin lifetime is consistent with the influence of nuclear spin fluctuations. Measuring the Overhauser effect in high magnetic fields, we observe a high degree of nuclear spin polarization, which is closely correlated to electron spin pumping.

Improved Resident Adherence to AAA Screening Guidelines via an Electronic Reminder.

PubMed

Sypert, David; Van Dyke, Kenneth; Dhillon, Namrata; Elliott, John O; Jordan, Kim

The 2014 United States Preventive Services Task Force systematic review found abdominal aortic aneurysm (AAA) screening decreased related mortality by close to half. Despite the simplicity of screening, research suggests poor adherence to the recommended AAA screening guidelines. Using the quality improvement plan-study-do-act cycle, we retrospectively established poor adherence to AAA screening and poor documentation of smoking history in our resident clinic. An electronic reminder was prospectively implemented into our electronic medical record (EMR) with the goal of improving screening rates. After 1 year, a retrospective chart review was conducted. Comparisons of the pre- and post-electronic reminder intervention data were made using chi-square tests and odds ratios (OR). The purposeful AAA screening rate improved 27.8% during the intervention, 40.3% (95% confidence interval [CI]: 28.6-52.0%) versus 12.5% (95% CI: 3.1-21.9%), p = .002, suggesting patients were more likely to be screened as a result of the electronic reminder, OR = 4.73 (95% CI: 1.77-12.65). This improvement translates to a large effect size, Cohen's d = 0.86 (95% CI: 0.31-1.40). Electronic reminders are a simple EMR addition that can provide evidence-based education while improving adherence rates with preventive health screening measures.

Internal Medicine Resident Engagement with a Laboratory Utilization Dashboard: Mixed Methods Study.

PubMed

Kurtzman, Gregory; Dine, Jessica; Epstein, Andrew; Gitelman, Yevgenly; Leri, Damien; Patel, Miltesh S; Ryskina, Kyra

2017-09-01

The objective of this study was to measure internal medicine resident engagement with an electronic medical record-based dashboard providing feedback on their use of routine laboratory tests relative to service averages. From January 2016 to June 2016, residents were e-mailed a snapshot of their personalized dashboard, a link to the online dashboard, and text summarizing the resident and service utilization averages. We measured resident engagement using e-mail read-receipts and web-based tracking. We also conducted 3 hour-long focus groups with residents. Using grounded theory approach, the transcripts were analyzed for common themes focusing on barriers and facilitators of dashboard use. Among 80 residents, 74% opened the e-mail containing a link to the dashboard and 21% accessed the dashboard itself. We did not observe a statistically significant difference in routine laboratory ordering by dashboard use, although residents who opened the link to the dashboard ordered 0.26 fewer labs per doctor-patient-day than those who did not (95% confidence interval, -0.77 to 0.25; = 0 .31). While they raised several concerns, focus group participants had positive attitudes toward receiving individualized feedback delivered in real time. © 2017 Society of Hospital Medicine.

Residents' behaviors, attitudes, and willingness to pay for recycling e-waste in Macau.

PubMed

Song, Qingbin; Wang, Zhishi; Li, Jinhui

2012-09-15

Large quantities of e-waste are presently being generated in Macau, but since recycling facilities and laws on e-waste still need to be developed, most e-waste cannot currently be properly treated. Moreover, little is known about residents' behaviors, attitudes, and their willingness to pay (WTP) for recycling e-waste. These issues are discussed in this study, based on a questionnaire survey on household electronic product usage. In 2010, "Life span completed" was the primary reason respondents abandoned their electronic products, accounting for about 37.97% of responses; the main disposal methods of e-waste in Macau were "Retailers retrieve from consumer" and "Sale to a recycling corporation." While having little understanding of e-waste disposal issues, most residents were still willing to hand their e-waste into the government for centralized collection. In addition, the respondents gave "telephone reservation" as their preferred collection method. Finally, the residents' WTP in Macau was estimated by the logistic regression method. It was found that education level, age and household income were the significant factors affecting residents' WTP. The monthly mean WTP was 20.03MOP (2.50 US dollar) per household, and the annual WTP was approximately 40,185,067 MOP (5,023,133 US dollar) for all of Macau. The results of our study can help managers develop more effective environmental management policies for e-waste disposal. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effect of multiple simple Robertsonian heterozygosity on chromosome pairing and fertility of wild-stock house mice (Mus musculus domesticus).

PubMed

Wallace, B M N; Searle, J B; Everett, C A

2002-01-01

The influence of Robertsonian (Rb) heterozygosity on fertility has been the subject of much study in the house mouse. However, these studies have been largely directed at single simple heterozygotes (heterozygous for a single Rb metacentric) or complex heterozygotes (heterozygous for several to many metacentrics which share common chromosome arms). In this paper we describe studies on male multiple simple heterozygotes, specifically the F(1) products of crosses between wild-stock mice homozygous for four or seven metacentrics and wild-stock mice with a standard all-acrocentric karyotype; these F(1) products were characterized by four and seven trivalents at meiosis I, respectively. Mice with the same karyotype, but two different genetic backgrounds were examined. Although a range of meiotic and fertility studies were conducted, particular emphasis was paid to analysis of chromosome pairing, previously not well-described in multiple simple heterozygous mice. The progression of spermatocytes through prophase I was followed by electron microscopy of surface spread material. As previously shown for single simple Rb heterozygotes, the trivalents that characterize multiple simple heterozygotes initially showed delayed pairing of the centromeric region and later showed side arm formation, resulting from non-homologous pairing by the centromeric ends of the acrocentric chromosomes. In the four trivalent groups of mice, 15 and 32% of trivalents showed unpairing in the centromeric region at mid pachytene; equivalent values were 29 and 39% for the seven trivalent groups. Pairing abnormalities (largely attachments and interlocks between trivalents and between a trivalent and the XY configuration) were observed in 18 and 23% of mid pachytene cells in the four trivalent groups and 36 and 49% of cells in the seven trivalent groups. The greater level of pachytene irregularity (unpairing and pairing abnormalities) in seven versus four trivalent heterozygotes was mirrored in terms of higher anaphase I nondisjunction frequency and lower germ cell counts. However, while pachytene irregularities appear to contribute to germ cell death, examples of male sterility in our material undoubtedly also involve genic incompatibilities. Copyright 2002 S. Karger AG, Basel

E-conferencing for delivery of residency didactics.

PubMed

Markova, Tsveti; Roth, Linda M

2002-07-01

While didactic conferences are an important component of residency training, delivering them efficiently is a challenge for many programs, especially when residents are located in multiple sites, as they are at Wayne State University School of Medicine in the Department of Family Medicine. Our residents find it difficult to travel from our hospitals or rotation sites to a centralized location for conferences. In order to overcome this barrier, we implemented distance learning and electronically delivered the conferences to the residents. We introduced an Internet-delivered, group-learning interactive conference model in which the lecturer is in one location with a group of residents and additional residents are in multiple locations. We launched the project in July 2001 using external company meeting services to schedule, coordinate, support, and archive the conferences. Equipment needed in each location consisted of a computer with an Internet connection, a telephone line, and a LCD projector (a computer monitor sufficed for small groups). We purposely chose simple distance-learning technology and used widely available equipment. Our e-conferencing had two components: (1) audio transmission via telephone connection and (2) visual transmission of PowerPoint presentations via the Internet. The telephone connection was open to all users, allowing residents to ask questions or make comments. Residents chose a conference location depending on geographic proximity to their rotation locations. Although we could accommodate up to 50 sites, we focused on a small number of locations in order to facilitate interaction among residents and faculty. Each conference session is archived and stored on the server for one week so those residents whose other residency-related responsibilities precluded attendance can view any conferences they have missed. E-conferencing proved to be an effective method of delivering didactics in our residency program. Its many advantages included ease of use, cost-efficiency, and wide availability of equipment. Residents had the advantage of both geographic and temporal independence. Our e-conferences were interactive, and in addition to a PowerPoint presentation, faculty provided Web sites and hyperlinks for references. Initial problems included slow-speed connection, the requirement for digital materials, and the need for residents and faculty to adjust to a new learning method. There was also a need for increased coordination at the sites and reliance on electronic communication. To assess the effectiveness of the program, residents completed knowledge pre- and post-tests and a conference evaluation form. We also monitored conference attendance rates. Preliminary results indicated positive resident attitudes toward distance learning and significant increases in conference attendance. To objectively evaluate this instructional delivery method, we will compare residents' knowledge gains in the face-to-face instructor group with those of the group to which the lecture is broadcast. Ultimately, we are hoping to offer this educational opportunity to other family practice residency programs in the area, to medical students interested in family medicine, and to community family physicians for continuing medical education. We are considering the addition of streaming video to the presentations in the future, once the bandwidth of the Internet connections is sufficient.

Effect of Commuter Time on Emergency Medicine Residents.

PubMed

Sampson, Christopher; Borenstein, Marc

2018-01-12

Background The impact of resident work hours on resident well-being and patient safety has long been a controversial issue. Objectives What has not been considered in resident work hour limitations is whether resident commuting time has any impact on a resident's total work hours or well-being. Methods A self-administered electronic survey was distributed to emergency medicine residents in 2016. Results The survey response was 8% (569/6828). Commuter time was 30 minutes or less in 70%. Two residents reported a commuter time of 76 to 90 minutes and one resident had a commuter time of 91 to 105 minutes. None reported commuter times greater than 105 minutes. Of most concern was that 29.3% of the residents reported falling asleep while driving their car home from work. We found 12% of respondents reporting being involved in a car collision while commuting. For residents with commute times greater than one hour, 66% reported they had fallen asleep while driving. When asked their opinion on the effect of commute time, those with commute times greater than one hour (75% of residents) responded that it was detrimental. Conclusions While the majority of emergency medicine residents in this survey have commuter times of 30 minutes or less, there is a small population of residents with commuter times of 76 to 105 minutes. At times, residents whose commute is up to 105 minutes each way could be traveling a total of more than 3.5 hours for each round trip. Given that these residents often work 12-hour shifts, these extended commuter times may be having detrimental effects on their health and well-being.

Effect of Commuter Time on Emergency Medicine Residents

PubMed Central

Borenstein, Marc

2018-01-01

Background The impact of resident work hours on resident well-being and patient safety has long been a controversial issue. Objectives What has not been considered in resident work hour limitations is whether resident commuting time has any impact on a resident's total work hours or well-being. Methods A self-administered electronic survey was distributed to emergency medicine residents in 2016. Results The survey response was 8% (569/6828). Commuter time was 30 minutes or less in 70%. Two residents reported a commuter time of 76 to 90 minutes and one resident had a commuter time of 91 to 105 minutes. None reported commuter times greater than 105 minutes. Of most concern was that 29.3% of the residents reported falling asleep while driving their car home from work. We found 12% of respondents reporting being involved in a car collision while commuting. For residents with commute times greater than one hour, 66% reported they had fallen asleep while driving. When asked their opinion on the effect of commute time, those with commute times greater than one hour (75% of residents) responded that it was detrimental. Conclusions While the majority of emergency medicine residents in this survey have commuter times of 30 minutes or less, there is a small population of residents with commuter times of 76 to 105 minutes. At times, residents whose commute is up to 105 minutes each way could be traveling a total of more than 3.5 hours for each round trip. Given that these residents often work 12-hour shifts, these extended commuter times may be having detrimental effects on their health and well-being. PMID:29545979

An evaluation of immunization education resources by family medicine residency directors.

PubMed

Nowalk, Mary Patricia; Zimmerman, Richard K; Middleton, Donald B; Sherwood, Roger A; Ko, Feng-Shou; Kimmel, Sanford R; Troy, Judith A

2007-01-01

Immunization is a rapidly evolving field, and teachers of family medicine are responsible for ensuring that they and their students are knowledgeable about the latest vaccine recommendations. A survey was mailed to 456 family medicine residency directors across the United States to obtain their evaluation of immunization resources developed by the Society of Teachers of Family Medicine's Group on Immunization Education. Frequencies, measures of central tendency, and differences between responses from 2001 to 2005 were analyzed. Directors of 261 (57%) family medicine residencies responded, with >80% reporting satisfaction with immunization teaching resources. The popularity of bound resources decreased from 2001 to 2005, while immunization Web sites increased in importance. The journal supplement, "Vaccines Across the Lifespan, 2005" was less frequently read in 2005 than its predecessor published in 2001, but quality ratings remained high. Use of the Web site, www.ImmunizationEd.org, and the Shots software for both desktop and handheld computers has increased since their creation. Electronic immunization teaching resources are increasingly popular among family medicine residencies. As the field continues to change, the use of electronic resources is expected to continue, since they are easily updated and, in the case of www.ImmunizationEd.org and Shots software, are available free of charge.

Nicotine replacement therapy, tobacco products, and electronic cigarettes in pharmacies in St. Louis, Missouri.

PubMed

Barnoya, Joaquin; Jin, Linda; Hudmon, Karen Suchanek; Schootman, Mario

2015-01-01

To compare availability of nicotine replacement therapy (NRT), tobacco products, and electronic cigarettes (e-cigarettes) in pharmacies in St. Louis, MO. Cross-sectional study, on-site store audits of 322 pharmacies. St. Louis, MO. 242 eligible community pharmacies located in the study area. Pharmacies were visited by trained research assistants who conducted a 5- to 10-minute store audit using a paper-based data collection tool. Availability, accessibility, and pricing of NRT as a function of neighborhood poverty rate and proportion of black residents as well as availability of tobacco products and e-cigarettes. NRT availability decreased as neighborhood poverty rate increased (P = 0.02). Availability without pharmacy personnel assistance also decreased with increasing poverty rate (r = -0.19; 95% CI = -0.06, -0.31) and higher percentage of black residents (r = -0.18; 95% CI = -0.06, -0.31). Prices were lower in neighborhoods with higher poverty rates (P = 0.02) and a higher percentage of black residents (P = 0.03). E-cigarettes were available in 43% of pharmacies, and their availability and price did not differ by poverty rate or percentage of black residents. Low access to NRT might perpetuate smoking disparities in disadvantaged and racially diverse neighborhoods. Study data support policies to ensure equal NRT access to reduce disparities.

Evaluation of Patient Handoff Methods on an Inpatient Teaching Service

PubMed Central

Craig, Steven R.; Smith, Hayden L.; Downen, A. Matthew; Yost, W. John

2012-01-01

Background The patient handoff process can be a highly variable and unstructured period at risk for communication errors. The morning sign-in process used by resident physicians at teaching hospitals typically involves less rigorous handoff protocols than the resident evening sign-out process. Little research has been conducted on best practices for handoffs during morning sign-in exchanges between resident physicians. Research must evaluate optimal protocols for the resident morning sign-in process. Methods Three morning handoff protocols consisting of written, electronic, and face-to-face methods were implemented over 3 study phases during an academic year. Study participants included all interns covering the internal medicine inpatient teaching service at a tertiary hospital. Study measures entailed intern survey-based interviews analyzed for failures in handoff protocols with or without missed pertinent information. Descriptive and comparative analyses examined study phase differences. Results A scheduled face-to-face handoff process had the fewest protocol deviations and demonstrated best communication of essential patient care information between cross-covering teams compared to written and electronic sign-in protocols. Conclusion Intern patient handoffs were more reliable when the sign-in protocol included scheduled face-to-face meetings. This method provided the best communication of patient care information and allowed for open exchanges of information. PMID:23267259

An Assessment of Pathology Resident Access to and Use of Technology: A Nationwide Survey.

PubMed

Vallangeon, Bethany D; Hawley, Jeffrey S; Sloane, Richard; Bean, Sarah M

2017-03-01

- Current technologies including digital slide scanners and handheld devices can revolutionize clinical practice and pathology graduate medical education (GME). The extent to which these technologies are used in pathology GME is unknown. - To determine the types of technologies used, usage amount, and how they are integrated into pathology residency/fellowship programs nationwide. - A 40-question online survey for residents/fellows was developed and administered via the Research Electronic Data Capture System after institutional review board approval. - Fifty-two program directors (37%) gave permission for participation. One-hundred seventy-one responses were received (18% response rate). Most respondents have access to personal technology (laptop = 78% [134 of 171]), smartphone = 81% [139 of 171], tablet = 49% [84 of 171]), and Web-based digital slide collections (82%, 141 of 171). Few residents are provided electronic devices by their programs (laptop = 22% [38 of 171], smartphone = 0.5% [1 of 171], and tablet = 12% [21 of 171]). Fifty-nine percent have access to digital slide scanners, 33% have access to a program-created database of digitized slides, and 52% use telepathology. Fifteen percent have access to asynchronous learning. Of those with access to video-recorded conferences, 89% review them. Program size was significantly positively correlated with resident access to program-provided laptops (P = .02) and tablets (P < .001), digital slide scanners (P = .01), and telepathology (P = .001). Of all devices, program-provided laptops are used most for professional work (60.5% use this device for more than 5 hours per day). - Most residents report access to multiple types of innovative technology, but incorporation of these tools within pathology training programs is highly variable. Opportunities for incorporating innovative technologies exist and could be further explored.

Improving prediction of fall risk among nursing home residents using electronic medical records.

PubMed

Marier, Allison; Olsho, Lauren E W; Rhodes, William; Spector, William D

2016-03-01

Falls are physically and financially costly, but may be preventable with targeted intervention. The Minimum Data Set (MDS) is one potential source of information on fall risk factors among nursing home residents, but its limited breadth and relatively infrequent updates may limit its practical utility. Richer, more frequently updated data from electronic medical records (EMRs) may improve ability to identify individuals at highest risk for falls. The authors applied a repeated events survival model to analyze MDS 3.0 and EMR data for 5129 residents in 13 nursing homes within a single large California chain that uses a centralized EMR system from a leading vendor. Estimated regression parameters were used to project resident fall probability. The authors examined the proportion of observed falls within each projected fall risk decile to assess improvements in predictive power from including EMR data. In a model incorporating fall risk factors from the MDS only, 28.6% of observed falls occurred among residents in the highest projected risk decile. In an alternative specification incorporating more frequently updated measures for the same risk factors from the EMR data, 32.3% of observed falls occurred among residents in the highest projected risk decile, a 13% increase over the base MDS-only specification. Incorporating EMR data improves ability to identify those at highest risk for falls relative to prediction using MDS data alone. These improvements stem chiefly from the greater frequency with which EMR data are updated, with minimal additional gains from availability of additional risk factor variables. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Arthroscopic training resources in orthopedic resident education.

PubMed

Koehler, Ryan; John, Tamara; Lawler, Jeffrey; Moorman, Claude; Nicandri, Gregg

2015-02-01

The purpose of this study was to determine the frequency of use, perceived effectiveness, and preference for arthroscopic surgical skill training resources. An electronic survey was sent to orthopedics residents, residency program directors, and orthopedic sports medicine attending physicians in the United States. The frequency and perceived effectiveness of 10 types of adjunctive arthroscopic skills training was assessed. Residents and faculty members were asked to rate their confidence in resident ability to perform common arthroscopic procedures. Surveys were completed by 40 of 152 (26.3%) orthopedic residency program directors, 70 of 426 (16.4%) sports medicine faculty, and 235 of 3,170 (7.4%) orthopedic residents. The use of adjunctive methods of training varied from only 9.8% of programs with virtual reality training to 80.5% of programs that used reading of published materials to develop arthroscopic skill. Practice on cadaveric specimens was viewed as the most effective and preferred adjunctive method of training. Residents trained on cadaveric specimens reported increased confidence in their ability to perform arthroscopic procedures. The resources for developing arthroscopic surgical skill vary considerably across orthopedic residency programs in the United States. Adjunctive training methods were perceived to be effective at supplementing traditional training in the operating room. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Occupational stress and related factors among surgical residents in Korea

PubMed Central

Kang, Sanghee; Jo, Hye Sung; Lee, Ji Sung; Kim, Chong Suk

2015-01-01

Purpose The application rate for surgical residents in Korea has continuously decreased over the past few years. The demanding workload and the occupational stress of surgical training are likely causes of this problem. The aim of this study was to investigate occupational stress and its related factors in Korean surgical residents. Methods With the support of the Korean Surgical Society, we conducted an electronic survey of Korean surgical residents related to occupational stress. We used the Korean Occupational Stress Scale (KOSS) to measure occupational stress. We analyzed the data focused on the stress level and the factors associated with occupational stress. Results The mean KOSS score of the surgical residents was 55.39, which was significantly higher than that of practicing surgeons (48.16, P < 0.001) and the average score of specialized professionals (46.03, P < 0.001). Exercise was the only factor found to be significantly associated with KOSS score (P = 0.001) in univariate analysis. However, in multiple linear regression analysis, the mean number of assigned patients, resident occupation rate and exercise were all significantly associated with KOSS score. Conclusion Surgical residents have high occupational stress compared to practicing surgeons and other professionals. Their mean number of assigned patients, resident recruitment rate and exercise were all significantly associated with occupational stress for surgical residents. PMID:26576407

Occupational stress and related factors among surgical residents in Korea.

PubMed

Kang, Sanghee; Jo, Hye Sung; Boo, Yoon Jung; Lee, Ji Sung; Kim, Chong Suk

2015-11-01

The application rate for surgical residents in Korea has continuously decreased over the past few years. The demanding workload and the occupational stress of surgical training are likely causes of this problem. The aim of this study was to investigate occupational stress and its related factors in Korean surgical residents. With the support of the Korean Surgical Society, we conducted an electronic survey of Korean surgical residents related to occupational stress. We used the Korean Occupational Stress Scale (KOSS) to measure occupational stress. We analyzed the data focused on the stress level and the factors associated with occupational stress. The mean KOSS score of the surgical residents was 55.39, which was significantly higher than that of practicing surgeons (48.16, P < 0.001) and the average score of specialized professionals (46.03, P < 0.001). Exercise was the only factor found to be significantly associated with KOSS score (P = 0.001) in univariate analysis. However, in multiple linear regression analysis, the mean number of assigned patients, resident occupation rate and exercise were all significantly associated with KOSS score. Surgical residents have high occupational stress compared to practicing surgeons and other professionals. Their mean number of assigned patients, resident recruitment rate and exercise were all significantly associated with occupational stress for surgical residents.

Unpaired Shocks during Extinction Weaken the Contextual Renewal of a Conditioned Discrimination

ERIC Educational Resources Information Center

Vervliet, Bram; Vansteenwegen, Deb; Hermans, Dirk

2010-01-01

Extinction is generally more fragile than conditioning, as illustrated by the contextual renewal effect. The traditional extinction procedure entails isolated presentations of the conditioned stimulus. Extinction may be boosted by adding isolated presentations of the unconditioned stimulus, as this should augment breaking the contingency between…

Implicit Relational Effects in Associative Recognition

ERIC Educational Resources Information Center

Algarabel, S.; Pitarque, A.; Combita, L. M.; Rodriguez, L. A.

2013-01-01

We study the contribution of implicit relatedness to associative recognition in two experiments. In the first experiment, we showed an implicit improvement in recognition when the stimulus elements of each word pair shared common letters and they were unpaired at test. Moreover, when asked to study the stimuli under divided attention, recollection…

A novel Web-based graduate medical education management system including ACGME compliance algorithms.

PubMed

Gauger, Paul G; Davis, Janice W; Orr, Peter J

2002-09-01

Administration of graduate medical education programs has become more difficult as compliance with ACGME work guidelines has assumed increased importance. These guidelines have caused many changes in the resident work environment, including the emergence of complicated cross-cover arrangements. Many participating residents (each with his or her own individual scheduling requirements) usually generate these schedules. Accordingly, schedules are often not submitted in a timely fashion and they may not be in compliance with the ACGME guidelines for maximum on-call assignments and mandatory days off. Our objective was the establishment of a Web-based system that guides residents in creating on-call schedules that follow ACGME guidelines while still allowing maximum flexibility -- thus allowing each resident to maintain an internal locus of control. A versatile and scalable system with password-protected user (resident) and administrator interfaces was created. An entire academic year is included, and past months and years are automatically archived. The residents log on within the first 15 days of the preceding month and choose their positions in a schedule template. They then make adjustments while receiving immediate summary feedback on compliance with ACGME guidelines. The schedule is electronically submitted to the educational administrator for final approval. If a cross-cover system is required, the program automatically generates an optimal schedule using both of the approved participating service schedules. The residents then have an additional five-day period to make adjustments in the cross-cover schedule while still receiving compliance feedback. The administrator again provides final approval electronically. The communication interface automatically pages or e-mails the residents when schedules are updated or approved. Since the information exists in a relational database, simple reporting tools are included to extract the information necessary to generate records for institutional GME management. Implementation of this program has been met with great enthusiasm from the institutional stakeholders. Specifically, residents have embraced the ability to directly control their schedules and have gained appreciation for the regulatory matrix in which they function. Institutional administrators have praised the improvement in compliance and the ease of documentation. We anticipate that the system will also meet with approval from reviewing regulatory bodies, as it generates and stores accurate information about the resident work environment. This program is robust and versatile enough to be modified for any GME training program in the country.

On Study of Application of Power Electronical Technology in Field of Energy Conservation

NASA Astrophysics Data System (ADS)

Song, Ke

2017-09-01

aiming at achieving the sustainable development in economy and improving living standard of the residents, the government departments in China have strengthened the promotion of green, low-carbon and sustainable development concepts. Under this context, the energy conservation concept is implemented during the implementation of social production and life activities. Currently, in order to ensure the improvement in social energy conservation benefits, the advanced technologies are applied by China's enterprises and residents. This paper, based on this, discusses the development situations of energy conservation in China, and analyzes the application of power electronical technology in the field of energy conservation, hoping to realize the sustainable development of energy conservation cause in China and to gain high yield.

Chemical structural analysis of diamondlike carbon films: II. Raman analysis

NASA Astrophysics Data System (ADS)

Takabayashi, Susumu; Ješko, Radek; Shinohara, Masanori; Hayashi, Hiroyuki; Sugimoto, Rintaro; Ogawa, Shuichi; Takakuwa, Yuji

2018-02-01

The chemical structure of diamondlike carbon (DLC) films, synthesized by photoemission-assisted glow discharge, has been analyzed by Raman spectroscopy. Raman analysis in conjunction with the sp2 cluster model clarified the film structure. The sp2 clusters in DLC films synthesized at low temperature preferred various aliphatic structures. Sufficient argon-ion assist allowed for formation of less strained DLC films containing large amounts of hydrogen. As the synthesis temperature was increased, thermal desorption of hydrogen left carbon dangling bonds with active unpaired electrons in the films, and the reactions that followed created strained films containing aromatic sp2 clusters. In parallel, the desorption of methane molecules from the growing surface by chemisorption of hydrogen radicals prevented the action of argon ions, promoting internal strain of the films. However, in synthesis at very high temperature, where sp2 clusters are sufficiently dominant, the strain was dissolved gradually. In contrast, the DLC films synthesized at low temperature were more stable than other films synthesized at the same temperature because of stable hydrogen-carbon bonds in the films.

Nucleophile sensitivity of Drosophila TRPA1 underlies light-induced feeding deterrence

PubMed Central

Du, Eun Jo; Ahn, Tae Jung; Wen, Xianlan; Seo, Dae-Won; Na, Duk L; Kwon, Jae Young; Choi, Myunghwan; Kim, Hyung-Wook; Cho, Hana; Kang, KyeongJin

2016-01-01

Solar irradiation including ultraviolet (UV) light causes tissue damage by generating reactive free radicals that can be electrophilic or nucleophilic due to unpaired electrons. Little is known about how free radicals induced by natural sunlight are rapidly detected and avoided by animals. We discover that Drosophila Transient Receptor Potential Ankyrin 1 (TRPA1), previously known only as an electrophile receptor, sensitively detects photochemically active sunlight through nucleophile sensitivity. Rapid light-dependent feeding deterrence in Drosophila was mediated only by the TRPA1(A) isoform, despite the TRPA1(A) and TRPA1(B) isoforms having similar electrophile sensitivities. Such isoform dependence re-emerges in the detection of structurally varied nucleophilic compounds and nucleophilicity-accompanying hydrogen peroxide (H2O2). Furthermore, these isoform-dependent mechanisms require a common set of TRPA1(A)-specific residues dispensable for electrophile detection. Collectively, TRPA1(A) rapidly responds to natural sunlight intensities through its nucleophile sensitivity as a receptor of photochemically generated radicals, leading to an acute light-induced behavioral shift in Drosophila. DOI: http://dx.doi.org/10.7554/eLife.18425.001 PMID:27656903

Photoinduced dynamics to photoluminescence in Ln3+ (Ln = Ce, Pr) doped β-NaYF4 nanocrystals computed in basis of non-collinear spin DFT with spin-orbit coupling

NASA Astrophysics Data System (ADS)

Han, Yulun; Vogel, Dayton J.; Inerbaev, Talgat M.; May, P. Stanley; Berry, Mary T.; Kilin, Dmitri S.

2018-03-01

In this work, non-collinear spin DFT + U approaches with spin-orbit coupling (SOC) are applied to Ln3+ doped β-NaYF4 (Ln = Ce, Pr) nanocrystals in Vienna ab initio Simulation Package taking into account unpaired spin configurations using the Perdew-Burke-Ernzerhof functional in a plane wave basis set. The calculated absorption spectra from non-collinear spin DFT + U approaches are compared with that from spin-polarised DFT + U approaches. The spectral difference indicates the importance of spin-flip transitions of Ln3+ ions. Suite of codes for nonadiabatic dynamics has been developed for 2-component spinor orbitals. On-the-fly nonadiabatic coupling calculations provide transition probabilities facilitated by nuclear motion. Relaxation rates of electrons and holes are calculated using Redfield theory in the reduced density matrix formalism cast in the basis of non-collinear spin DFT + U with SOC. The emission spectra are calculated using the time-integrated method along the excited state trajectories based on nonadiabatic couplings.

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

Jian, Tian; Lopez, Gary V.; Wang, Lai-Sheng, E-mail: Lai-Sheng-Wang@brown.edu

We report the observation of a manganese-centered tubular boron cluster (MnB{sub 16}{sup −}), which is characterized by photoelectron spectroscopy and ab initio calculations. The relatively simple pattern of the photoelectron spectrum indicates the cluster to be highly symmetric. Ab initio calculations show that MnB{sub 16}{sup −} has a Mn-centered tubular structure with C{sub 4v} symmetry due to first-order Jahn-Teller effect, while neutral MnB{sub 16} reduces to C{sub 2v} symmetry due to second-order Jahn-Teller effect. In MnB{sub 16}{sup −}, two unpaired electrons are observed, one on the Mn 3d{sub z{sup 2}} orbital and another on the B{sub 16} tube, making itmore » an unusual biradical. Strong covalent bonding is found between the Mn 3d orbitals and the B{sub 16} tube, which helps to stabilize the tubular structure. The current result suggests that there may exist a whole class of metal-stabilized tubular boron clusters. These metal-doped boron clusters provide a new bonding modality for transition metals, as well as a new avenue to design boron-based nanomaterials.« less

High reactivity of nanosized niobium oxide cluster cations in methane activation: A comparison with vanadium oxides

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

Ding, Xun-Lei, E-mail: dingxl@ncepu.edu.cn, E-mail: chemzyx@iccas.ac.cn; Wang, Dan; Wu, Xiao-Nan

2015-09-28

The reactions between methane and niobium oxide cluster cations were studied and compared to those employing vanadium oxides. Hydrogen atom abstraction (HAA) reactions were identified over stoichiometric (Nb{sub 2}O{sub 5}){sub N}{sup +} clusters for N as large as 14 with a time-of-flight mass spectrometer. The reactivity of (Nb{sub 2}O{sub 5}){sub N}{sup +} clusters decreases as the N increases, and it is higher than that of (V {sub 2}O{sub 5}){sub N}{sup +} for N ≥ 4. Theoretical studies were conducted on (Nb{sub 2}O{sub 5}){sub N}{sup +} (N = 2–6) by density functional calculations. HAA reactions on these clusters are all favorablemore » thermodynamically and kinetically. The difference of the reactivity with respect to the cluster size and metal type (Nb vs V) was attributed to thermodynamics, kinetics, the electron capture ability, and the distribution of the unpaired spin density. Nanosized Nb oxide clusters show higher HAA reactivity than V oxides, indicating that niobia may serve as promising catalysts for practical methane conversion.« less

The heat of formation of gaseous PuO(2)2+ from relativistic density functional calculations.

PubMed

Moskaleva, Lyudmila V; Matveev, Alexei V; Dengler, Joachim; Rösch, Notker

2006-08-28

Using a set of model reactions, we estimated the heat of formation of gaseous PuO2(2+) from quantum-chemical reaction enthalpies and experimental heats of formation of reference species. To this end, we carried out relativistic density functional calculations on the molecules PuO(2)2+, PuO2, PuF6, and PuF4. We used a revised variant (PBEN) of the Perdew-Burke-Ernzerhof gradient-corrected exchange-correlation functional, and we accounted for spin-orbit interaction in a self-consistent fashion. As open-shell Pu species with two or more unpaired 5f electrons are involved, spin-orbit interaction significantly affects the energies of the model reactions. Our theoretical estimate for the heat of formation DeltafH degree 0(PuO2(2+),g), 418+/-15 kcal mol-1, evaluated using plutonium fluorides as references, is in good agreement with a recent experimental result, 413+/-16 kcal mol-1. The theoretical value connected to the experimental heat of formation of PuO2(g) has a notably higher uncertainty and therefore was not included in the final result.

A real-time computer model to assess resident work-hours scenarios.

PubMed

McDonald, Furman S; Ramakrishna, Gautam; Schultz, Henry J

2002-07-01

To accurately model residents' work hours and assess options to forthrightly meet Residency Review Committee-Internal Medicine (RRC-IM) requirements. The requirements limiting residents' work hours are clearly defined by the Accreditation Council for Graduate Medical Education (ACGME) and the RRC-IM: "When averaged over any four-week rotation or assignment, residents must not spend more than 80 hours per week in patient care duties."(1) The call for the profession to realistically address work-hours violations is of paramount importance.(2) Unfortunately, work hours are hard to calculate. We developed an electronic model of residents' work-hours scenarios using Microsoft Excel 97. This model allows the input of multiple parameters (i.e., call frequency, call position, days off, short-call, weeks per rotation, outpatient weeks, clinic day of the week, additional time due to clinic) and start and stop times for post-call, non-call, short-call, and weekend days. For each resident on a rotation, the model graphically demonstrates call schedules, plots clinic days, and portrays all possible and preferred days off. We tested the model for accuracy in several scenarios. For example, the model predicted average work hours of 85.1 hours per week for fourth-night-call rotations. This was compared with logs of actual work hours of 84.6 hours per week. Model accuracy for this scenario was 99.4% (95% CI 96.2%-100%). The model prospectively predicted work hours of 89.9 hours/week in the cardiac intensive care unit (CCU). Subsequent surveys found mean CCU work hours of 88, 1 hours per week. Model accuracy for this scenario was 98% (95% CI 93.2-100%). Thus validated, we then used the model to test proposed scenarios for complying with RRC-IM limits. The flexibility of the model allowed demonstration of the full range of work-hours scenarios in every rotation of our 36-month program. Demonstrations of status-quo work-hours scenarios were presented to faculty as well as real-time demonstrations of the feasibility, or unfeasibility, of their proposed solutions. The model clearly demonstrated that non-call (i.e., short-call) admissions without concomitant decreases in overnight call frequency resulted in substantial increases in total work hours. Attempts to "get the resident out" an hour or two earlier each day had negligible effects on total hours and were unrealistic paper solutions. For fourth-night-call rotations, the addition of a "golden weekend" (i.e., a fifth day off per month) was found to significantly reduce work hours. The electronic model allowed the development of creative schedules for previously third-night-call rotations that limit resident work hours without decreasing continuity of care by scheduling overnight call every sixth night alternating with sixth-night-short-call rotations. Our electronic model is sufficiently robust to accurately estimate work hours on multiple and varied rotations. This model clearly demonstrates that it is very difficult to meet the RRC-IM work-hours limitations under standard fourth-night-call schedules with only four days off per month. We are successfully using our model to test proposed alternative scenarios, to overcome faculty misconceptions about resident work-hours "solutions," and to make changes to our call schedules that both are realistic for residents to accomplish and truly diminish total resident work hours toward the requirements of the RRC-IM.

[Teaching pediatrics to residents via conventional lectures in France: A national survey from students].

PubMed

Girard, B; Bendavid, M; Faivre, J-C; Salleron, J; Debillon, T; Claris, O; Chabrol, B; Schweitzer, C; Gajdos, V

2017-08-01

To assess the point of view of young physicians training in pediatrics in France on their theoretical courses during residency. A free-access electronic anonymous survey was sent three times by e-mail to the 1215 residents in pediatrics, from July to October 2015. Fifty-seven percent of French residents in pediatrics responded to the survey. It was established that they took part in six (range, 3-10) half-days of specific theoretical teaching in pediatrics from November 2014 to mid-April 2015. Only 54% participated in more than 75% of regional theoretical training. The main self-declared reason for their absence was that they could not leave their clinical activities. Fifty-three per cent of the residents took part in additional training, 45% of them because they found the primary theoretical training insufficient. The overall quality of the theoretical teaching was rated 5 (range, 3-7) out of 10. Eighty-five percent of residents expected to be evaluated on their knowledge during their residency. In pediatrics, additional training is individually undertaken because they deemed their initial training insufficient during their residency. An evaluation of knowledge is requested by residents. The reform of the national residency program must take into account these results in redesigning the theoretical training in pediatrics, integrating innovative teaching techniques to daily practice, for example. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Resident use of the Internet, e-mail, and personal electronics in the care of surgical patients.

PubMed

Plant, Mathew A; Fish, Joel S

2015-01-01

The use of smartphones, e-mail, and the Internet has affected virtually all areas of patient care. Current university and hospital policies concerning the use of devices may be incongruent with day-to-day patient care. The goal was to assess the current usage patterns of the Internet, e-mail, and personal electronics for clinical purposes by surgical residents as well as their communication habits and preferences. Also assessed was residents' knowledge regarding the institutional policies surrounding these issues. Surgical residents (n = 294) at a large teaching institution were surveyed regarding their knowledge of university policies as well as daily use of various communication technologies. Communication preferences were determined using theoretical clinical scenarios. Our survey with a response rate of 54.7% (n = 161) revealed that 93.8% of participants indicated daily Internet use for clinical duties. Most respondents (72%) were either completely unaware of the existence of guidelines for its use or aware but had no familiarity with their content. Use of e-mail for clinical duties was common (85%), and 74% of the respondents rated e-mail as "very important" or "extremely important" for patient care. Everyone who responded had a mobile phone with 98.7% being "smartphones," which the majority (82.9%) stated was "very important" or "extremely important" for patient care. Text messaging was the primary communication method for 57.8% of respondents. The traditional paging system was the primary communication method for only 1.3% of respondents and the preferred method for none. Daily use of technology is the norm among residents; however, knowledge of university guidelines was exceedingly low. Residents need better education regarding current guidelines. Current guidelines do not reflect current clinical practice. Hospitals should consider abandoning the traditional paging system and consider facilitating better use of residents' mobile phones.

Development of Electronic Medical Record-Based "Rounds Report" Results in Improved Resident Efficiency, More Time for Direct Patient Care and Education, and Less Resident Duty Hour Violations.

PubMed

Ham, Phillip B; Anderton, Toby; Gallaher, Ryan; Hyrman, Mike; Simmerman, Erika; Ramanathan, Annamalai; Fallaw, David; Holsten, Steven; Howell, Charles Gordon

2016-09-01

Surgeons frequently report frustration and loss of efficiency with electronic medical record (EMR) systems. Together, surgery residents and a programmer at Augusta University created a rounds report (RR) summarizing 24 hours of vitals, intake/output, labs, and other values for each inpatient that were previously transcribed by hand. The objective of this study was to evaluate the RR's effect on surgery residents. Surgery residents were queried to assess the RR's impact. Outcome measures were time spent preparing for rounds, direct patient care time, educational activity time, rates of incorrect/incomplete data on rounds, and rate of duty hour violations. Hospital wide, 17,200 RRs were generated in the 1-month study. Twenty-three surgery residents participated. Time spent preparing for rounds decreased per floor patient (15.6 ± 3.0 vs 6.0 ± 1.2, P < 0.0001) and per intensive care unit patient (19.9 ± 2.9 vs 7.5 ± 1.2 P < 0.0001). The work day spent in direct patient care increased from 45.1 ± 5.6 to 54.0 ± 5.7 per cent (P = 0.0044). Educational activity time increased from 35.2 ± 5.4 to 54.7 ± 7.1 minutes per resident per day (P = 0.0004). Reported duty hour violations decreased 58 per cent (P < 0.0001). American Board of Surgery in Training exam scores trended up, and estimates of departmental annual financial savings range from $66,598 to $273,141 per year. Significant improvements occur with surgeon designed EMR tools like the RR. Hospitals and EMR companies should pair interested surgeons with health information technology developers to facilitate EMR enhancements. Improvements like RRs can have broad ranging, multidisciplinary impact and should be standard in all EMRs used for inpatient care at academic medical centers.

The association of departmental leadership gender with that of faculty and residents in radiology.

PubMed

Shah, Anand; Braga, Larissa; Braga-Baiak, Andresa; Jacobs, Danny O; Pietrobon, Ricardo

2007-08-01

Although the number of women graduating from medical school continues to increase, their representation in radiology residency programs has not increased over the past 10 years. We examined whether the gender of radiology faculty and residents differed according to the gender of the departmental leadership. We issued an anonymous Web-based survey via e-mail to all 188 radiology residency program directors listed in the Fellowship and Residency Electronic Interactive Database (FREIDA Online). Data regarding the gender of the department chairperson, residency program director, faculty, and residents were collected. The institutional review board granted a waiver for this study, and all subjects provided informed consent. Of the 84 program directors who responded, 9 (10.7%) were chaired by females and 75 (89.3%) by males; residency program director positions were held by 36 (42.9%) females and 48 (57.1%) males. More programs were located in the northeastern United States (n = 31, 36.9%) than in any other region, and more were self-described as academic (n = 36, 42.9%) than any other practice type. Programs that were led by a male chairperson had a similar proportion of female faculty (25.2% versus 27.3%; P = .322) and residents (26.2% versus 27.4%; P = .065) compared with those led by a female. Similarly, radiology departments with a male residency program director had a similar proportion of female residents (24.8% versus 28.7%; P = .055) compared with programs with a female residency program director. The gender composition of radiology faculty and residents does not differ significantly according to the gender of the departmental chairperson or residency program director. Nevertheless, there continues to be a disparity in the representation of women among radiology faculty and residents.

Differences in Access to and Use of Electronic Personal Health Information Between Rural and Urban Residents in the United States.

PubMed

Greenberg, Alexandra J; Haney, Danielle; Blake, Kelly D; Moser, Richard P; Hesse, Bradford W

2018-02-01

The increase in use of health information technologies (HIT) presents new opportunities for patient engagement and self-management. Patients in rural areas stand to benefit especially from increased access to health care tools and electronic communication with providers. We assessed the adoption of 4 HIT tools over time by rural or urban residency. Analyses were conducted using data from 7 iterations of the National Cancer Institute's Health Information National Trends Survey (HINTS; 2003-2014). Rural/urban residency was based on the USDA's 2003 Rural-Urban Continuum Codes. Outcomes of interest included managing personal health information online; whether providers maintain electronic health records (EHRs); e-mailing health care providers; and purchasing medicine online. Bivariate analyses and logistic regression were used to assess relationships between geography and outcomes, controlling for sociodemographic characteristics. In total, 6,043 (17.6%, weighted) of the 33,749 respondents across the 7 administrations of HINTS lived in rural areas. Rural participants were less likely to report regular access to Internet (OR = 0.70, 95% CI = 0.61-0.80). Rural respondents were neither more nor less likely to report that their health care providers maintained EHRs than were urban respondents; however, they had decreased odds of managing personal health information online (OR = 0.59, 95% CI = 0.40-0.78) and e-mailing health care providers (OR = 0.62, 95% CI = 0.49-0.77). The digital divide between rural and urban residents extends to HIT. Additional investigation is needed to determine whether the decreased use of HIT may be due to lack of Internet connectivity or awareness of these tools. © 2016 National Rural Health Association.

Identifying areas of weakness in thoracic surgery residency training: a comparison of the perceptions of residents and program directors.

PubMed

Edwards, Janet P; Schofield, Adam; Paolucci, Elizabeth Oddone; Schieman, Colin; Kelly, Elizabeth; Servatyari, Ramin; Dixon, Elijah; Ball, Chad G; Grondin, Sean C

2014-01-01

To identify core thoracic surgery procedures that require increased emphasis during thoracic surgery residency for residents to achieve operative independence and to compare the perspectives of residents and program directors in this regard. A modified Delphi process was used to create a survey that was distributed electronically to all Canadian thoracic surgery residents (12) and program directors (8) addressing the residents' ability to perform 19 core thoracic surgery procedures independently after the completion of residency. Residents were also questioned about the adequacy of their operative exposure to these 19 procedures during their residency training. A descriptive summary including calculations of frequencies and proportions was conducted. The perceptions of the 2 groups were then compared using the Fisher exact test employing a Bonferroni correction. The relationship between residents' operative exposure and their perceived operative ability was explored in the same fashion. The response rate was 100% for residents and program directors. No statistical differences were found between residents' and program directors' perceptions of residents' ability to perform the 19 core procedures independently. Both groups identified lung transplantation, first rib resection, and extrapleural pneumonectomy as procedures for which residents were not adequately prepared to perform independently. Residents' subjective ratings of operative exposure were in good agreement with their reported operative ability for 13 of 19 procedures. This study provides new insight into the perceptions of thoracic surgery residents and their program directors regarding operative ability. This study points to good agreement between residents and program directors regarding residents' surgical capabilities. This study provides information regarding potential weaknesses in thoracic surgery training, which may warrant an examination of the curricula of existing programs as well as a reconsideration of what the scope of practice of a general thoracic surgeon should entail. © 2013 Published by Association of Program Directors in Surgery on behalf of Association of Program Directors in Surgery.

Relating hyporheic fluxes, residence times, and redox-sensitive biogeochemical processes upstream of beaver dams

USGS Publications Warehouse

Briggs, Martin A.; Lautz, Laura; Hare, Danielle K.

2013-01-01

¨hler number seemed to overestimate the actual transition as indicated by multiple secondary electron acceptors, illustrating the gradient nature of anaerobic transition. Temporal flux variability in low-flux morphologies generated a much greater range in hyporheic redox conditions compared to high-flux zones, and chemical responses to changing flux rates were consistent with those predicted from the empirical relationship between redox condition and residence time. The Raz tracer revealed that hyporheic flow paths have strong net aerobic respiration, particularly at higher residence time, but this reactive exchange did not affect the net stream signal at the reach scale.

Should we Google it? Resource use by internal medicine residents for point-of-care clinical decision making.

PubMed

Duran-Nelson, Alisa; Gladding, Sophia; Beattie, Jim; Nixon, L James

2013-06-01

To determine which resources residents use at the point-of-care (POC) for decision making, the drivers for selection of these resources, and how residents use Google/Google Scholar to answer clinical questions at the POC. In January 2012, 299 residents from three internal medicine residencies were sent an electronic survey regarding resources used for POC decision making. Resource use frequency and factors influencing choice were determined using descriptive statistics. Binary logistic regression analysis was performed to determine relationships between the independent variables. A total of 167 residents (56%) responded; similar numbers responded at each level of training. Residents most frequently reported using UpToDate and Google at the POC at least daily (85% and 63%, respectively), with speed and trust in the quality of information being the primary drivers of selection. Google, used by 68% of residents, was used primarily to locate Web sites and general information about diseases, whereas Google Scholar, used by 30% of residents, tended to be used for treatment and management decisions or locating a journal article. The findings suggest that internal medicine residents use UpToDate most frequently, followed by consultation with faculty and the search engines Google and Google Scholar; speed, trust, and portability are the biggest drivers for resource selection; and time and information overload appear to be the biggest barriers to resources such as Ovid MEDLINE. Residents frequently used Google and may benefit from further training in information management skills.

Pregnancy and the Plastic Surgery Resident.

PubMed

Garza, Rebecca M; Weston, Jane S; Furnas, Heather J

2017-01-01

Combining pregnancy with plastic surgery residency has historically been difficult. Two decades ago, 36 percent of plastic surgery program directors surveyed actively discouraged pregnancy among residents, and 33 percent of women plastic surgeons suffered from infertility. Most alarmingly, 26 percent of plastic surgery trainees had had an elective abortion during residency. With increasing numbers of women training in plastic surgery, this historical lack of support for pregnancy deserves further attention. To explore the current accommodations made for the pregnant plastic surgery resident, an electronic survey was sent to 88 plastic surgery program directors in the United States. Fifty-four responded, for a response rate of 61.36 percent. On average, a director trained a total of 7.91 women among 17.28 residents trained over 8.19 years. Of the women residents, 1.43 were pregnant during a director's tenure, with 1.35 of those residents taking maternity leave. An average 1.75 male residents took paternity leave. Approximately one-third of programs had a formal maternity/paternity leave policy (36.54 percent) which, in most cases, was limited to defining allowed weeks of leave, time required to fulfill program requirements, and remuneration during leave. This survey of plastic surgery directors is a first step in defining the challenges training programs face in supporting the pregnant resident. Directors provided comments describing their challenges accommodating an absent resident in a small program and complying with the American Board of Plastic Surgery's required weeks of training per year. A discussion of these challenges is followed by suggested solutions.

International Health Experiences in Family Medicine Residency Training.

PubMed

Porter, Maribeth; Mims, Lisa; Garven, Chad; Gavin, Jennifer; Carek, Peter; Diaz, Vanessa

2016-02-01

International health experiences (IHEs) have been associated with improved clinical skills, altruistic attitudes, cross-cultural sensitivity, and exposure to community medicine for residents and medical students. Although an increasing number of family medicine residencies offer IHEs, there are currently no standardized competencies or guidelines for developing IHEs. The aim of this study was to examine the content of IHEs in order to provide an overview of the current landscape of global health training in family medicine residency programs. Residency programs self-identifying as offering IHEs on the American Medical Association's (AMA) FREIDA Online website were emailed an electronic survey with questions regarding IHE characteristics, resident selection criteria, faculty support, motivations for participation, challenges to implementation, and funding. Of the 153 programs that responded, 84% still offered IHEs. Most IHEs are 3--4 weeks (71.1%) and are funded by the resident (74.2%). Faculty from the resident's department or institution generally provide supervision (76.6%) and have undergone some type of specialized training in global health (65.6%). Being in good academic standing was the most important eligibility criteria for residents participating in an IHE (86.7%), and funding was reported as the most challenging aspect (62.5%) of offering IHEs. IHEs are increasing in number and receiving more funding, but the experiences are variable among residency programs. While most program directors believe residents participate in IHEs to gain exposure with underserved populations, only a small percentage (5.5%) include a commitment to community service as part of a requirement for participation in an IHE.

Personal Therapy in Psychiatry Residency Training: A National Survey of Canadian Psychiatry Residents.

PubMed

Hadjipavlou, George; Halli, Priyanka; Hernandez, Carlos A Sierra; Ogrodniczuk, John S

2016-02-01

The authors collected nationally representative data on Canadian residents' experiences with and perspectives on personal psychotherapy in their psychiatric training. A 43-item questionnaire was distributed electronically to all current psychiatry residents in Canada (N = 839). Four hundred residents from every program across Canada returned the survey (response rate 47.7%). The prevalence of personal therapy at any time was 55.3%, with 42.8% receiving personal therapy during residency. Of residents who undertook personal psychotherapy, 59.3% engaged in weekly therapy, 74.1% received psychodynamic psychotherapy, and 81.5% participated in long-term therapy (>1 year). Personal growth, self-understanding, and professional development were the most common reasons for engaging in personal therapy; however, one-third of residents did so to alleviate symptoms of depression, anxiety, or other mental health concerns. Time was the most important factor impeding residents from personal therapy; only 8.8% found stigma to act as a barrier. The vast majority of residents rated their experience with personal therapy as having a positive or very positive impact on their personal life (84.8%) and overall development as psychiatrists (81.8%). For 64% of respondents, personal therapy had an important or very important role in psychiatry residency training. Residents who received personal therapy rated themselves as better able to understand what happens moment by moment during therapy sessions, detect and deal with patients' emotional reactions, and constructively use their personal reactions to patients. Interest in personal therapy remains strong among psychiatry trainees in Canada. Residents who engaged in psychotherapy endorsed greater confidence in psychotherapy and rated their psychotherapy skills more favorably than those who had never been in the patient role, supporting the view of personal therapy as an important adjunct to psychotherapy training during residency.

Live broadcast of laparoscopic surgery to handheld computers.

PubMed

Gandsas, A; McIntire, K; Park, A

2004-06-01

Thanks to advances in computer power and miniaturization technology, portable electronic devices are now being used to assist physicians with various applications that extend far beyond Web browsing or sending e-mail. Handheld computers are used for electronic medical records, billing, coding, and to enable convenient access to electronic journals for reference purposes. The results of diagnostic investigations, such as laboratory results, study reports, and still radiographic pictures, can also be downloaded into portable devices for later view. Handheld computer technology, combined with wireless protocols and streaming video technology, has the added potential to become a powerful educational tool for medical students and residents. The purpose of this study was to assess the feasibility of transferring multimedia data in real time to a handheld computer via a wireless network and displaying them on the computer screens of clients at remote locations. A live laparoscopic splenectomy was transmitted live to eight handheld computers simultaneously through our institution's wireless network. All eight viewers were able to view the procedure and to hear the surgeon's comments throughout the entire duration of the operation. Handheld computer technology can play a key role in surgical education by delivering information to surgical residents or students when they are geographically distant from the actual event. Validation of this new technology by conducting clinical research is still needed to determine whether resident physicians or medical students can benefit from the use of handheld computers.

An Internet-Based Method for Extracting Nursing Home Resident Sedative Medication Data From Pharmacy Packing Systems: Descriptive Evaluation

PubMed Central

Gee, Peter; Westbury, Juanita; Bindoff, Ivan; Peterson, Gregory

2017-01-01

Background Inappropriate use of sedating medication has been reported in nursing homes for several decades. The Reducing Use of Sedatives (RedUSe) project was designed to address this issue through a combination of audit, feedback, staff education, and medication review. The project significantly reduced sedative use in a controlled trial of 25 Tasmanian nursing homes. To expand the project to 150 nursing homes across Australia, an improved and scalable method of data collection was required. This paper describes and evaluates a method for remotely extracting, transforming, and validating electronic resident and medication data from community pharmacies supplying medications to nursing homes. Objective The aim of this study was to develop and evaluate an electronic method for extracting and enriching data on psychotropic medication use in nursing homes, on a national scale. Methods An application uploaded resident details and medication data from computerized medication packing systems in the pharmacies supplying participating nursing homes. The server converted medication codes used by the packing systems to Australian Medicines Terminology coding and subsequently to Anatomical Therapeutic Chemical (ATC) codes for grouping. Medications of interest, in this case antipsychotics and benzodiazepines, were automatically identified and quantified during the upload. This data was then validated on the Web by project staff and a “champion nurse” at the participating home. Results Of participating nursing homes, 94.6% (142/150) had resident and medication records uploaded. Facilitating an upload for one pharmacy took an average of 15 min. A total of 17,722 resident profiles were extracted, representing 95.6% (17,722/18,537) of the homes’ residents. For these, 546,535 medication records were extracted, of which, 28,053 were identified as antipsychotics or benzodiazepines. Of these, 8.17% (2291/28,053) were modified during validation and verification stages, and 4.75% (1398/29,451) were added. The champion nurse required a mean of 33 min website interaction to verify data, compared with 60 min for manual data entry. Conclusions The results show that the electronic data collection process is accurate: 95.25% (28,053/29,451) of sedative medications being taken by residents were identified and, of those, 91.83% (25,762/28,053) were correct without any manual intervention. The process worked effectively for nearly all homes. Although the pharmacy packing systems contain some invalid patient records, and data is sometimes incorrectly recorded, validation steps can overcome these problems and provide sufficiently accurate data for the purposes of reporting medication use in individual nursing homes. PMID:28778844

Teaching, leadership, scholarly productivity, and level of activity in the chiropractic profession: a study of graduates of the Los Angeles College of Chiropractic radiology residency program

PubMed Central

Young, Kenneth J.; Siordia, Lawrence

2012-01-01

Objective The purpose of this study was to track the graduates of the Los Angeles College of Chiropractic (LACC) radiology residency program, review their scholarly productivity, and report those involved in teaching and leadership positions. Methods Former LACC residents’ career information was identified through publicly available electronic documents including Web sites and social media. PubMed and the Index to Chiropractic Literature databases were searched for chiropractic graduate job surveys, and proportional comparisons were made between the career paths of LACC radiology residency graduates and those of non–residency-trained chiropractors. Results Of 47 former LACC residents, 28 (60%) have or previously had careers in tertiary (chiropractic) education; and 12 (26%) have attained a department chair position or higher at tertiary teaching institutions. Twenty-two (47%) have or previously had private radiology practices, whereas 11 (23%) have or previously had clinical chiropractic practices. Often, residency graduates hold or have held 2 of these positions at once; and one, all 3. Chapters or books were authored by 13 (28%). Conclusion Radiology residency LACC graduates are professionally active, particularly in education, and demonstrate scholarly productivity. PMID:23966885

Computer usage and task-switching during resident's working day: Disruptive or not?

PubMed

Méan, Marie; Garnier, Antoine; Wenger, Nathalie; Castioni, Julien; Waeber, Gérard; Marques-Vidal, Pedro

2017-01-01

Recent implementation of electronic health records (EHR) has dramatically changed medical ward organization. While residents in general internal medicine use EHR systems half of their working time, whether computer usage impacts residents' workflow remains uncertain. We aimed to observe the frequency of task-switches occurring during resident's work and to assess whether computer usage was associated with task-switching. In a large Swiss academic university hospital, we conducted, between May 26 and July 24, 2015 a time-motion study to assess how residents in general internal medicine organize their working day. We observed 49 day and 17 evening shifts of 36 residents, amounting to 697 working hours. During day shifts, residents spent 5.4 hours using a computer (mean total working time: 11.6 hours per day). On average, residents switched 15 times per hour from a task to another. Task-switching peaked between 8:00-9:00 and 16:00-17:00. Task-switching was not associated with resident's characteristics and no association was found between task-switching and extra hours (Spearman r = 0.220, p = 0.137 for day and r = 0.483, p = 0.058 for evening shifts). Computer usage occurred more frequently at the beginning or ends of day shifts and was associated with decreased overall task-switching. Task-switching occurs very frequently during resident's working day. Despite the fact that residents used a computer half of their working time, computer usage was associated with decreased task-switching. Whether frequent task-switches and computer usage impact the quality of patient care and resident's work must be evaluated in further studies.

Resident Fuel Levels: Reframing, Assessing, and Addressing Well-Being.

PubMed

Scielzo, Shannon Amerilda; Weigle, David C; Kazi, Salahuddin Dino

2018-04-01

To optimize resident learning, programs need to readily assess resident well-being. There is a lack of easy-to-use, acceptable instruments for this task. We created a well-being "fuel gauge," and assessed the acceptability and feasibility of this weekly electronic communication pipeline for residents to report and discuss their well-being. A well-being fuel gauge assessment was administered weekly over the course of 1 academic year (July 2016 to June 2017) in a large internal medicine residency program. The well-being gauge asked residents to report their fuel levels using a 1 to 5 Likert-type scale (1, empty ; 3, half tank ; and 5, full tank ). Residents who provided low scores (1 or 2) were contacted by program leadership, and the program director sent weekly e-mail updates that addressed residents' comments on their well-being fuel gauge. Of 163 residents, 149 (91%) provided data on their well-being fuel gauge, with a 53% average weekly response rate. Fifty-four percent of residents (80 of 149) reported a low score over the course of the year, and 4 residents only used the assessment to report a low score. Comments on average consisted of 280 characters (SD = 357) and were lengthier and more prevalent with lower fuel gauge scores. We analyzed the relationship between scores and comments. The well-being fuel gauge was well accepted by most residents and was easy to administer and to oversee by program directors. It facilitated ongoing monitoring of well-being and follow-up to address factors contributing to low well-being.

Myths and realities of the 80-hour work week.

PubMed

Schenarts, Paul J; Anderson Schenarts, Kimberly D; Rotondo, Michael F

2006-01-01

Myths are so ingrained into cultural traditions that emotion frequently overshadows a rational evaluation of the facts. The reduction in resident work hours has resulted in the formation of several myths. The purpose of this review is to examine the published data on resident work hours to separate out myth from reality. An electronic database was searched for publications related to resident training, work-hours, continuity of care, sleep deprivation, quality of life, patient safety, clinical/operative experience, faculty work hours, and surgical education. Sleep deprivation has been shown to be harmful, and residents played a role in advocating for work-hour limits. Surgical residents have seen a less dramatic improvement in quality of life compared with other disciplines. Work-hour reductions have decreased participation in clinic but have not resulted in a significant decline in clinical or operative exposure. Limiting resident work hours will unlikely result in a decrease health-care cost. Reduction in resident work hours has not resulted in an improvement or deterioration in patient outcome. Reduction of work hours has not increased faculty work hours nor made surgery a more attractive career choice. Despite strongly held opinions, resident work-hour reduction has resulted in little significant change in lifestyle, clinical exposure, patient well-being, faculty work hours, or medical student recruitment.

Residency Program Directors' View on the Value of Teaching.

PubMed

Korte, Catherine; Smith, Andrew; Pace, Heather

2016-08-01

There is no standardization for teaching activities or a requirement for residency programs to offer specific teaching programs to pharmacy residents. This study will determine the perceived value of providing teaching opportunities to postgraduate year 1 (PGY-1) pharmacy residents in the perspective of the residency program director. The study will also identify the features, depth, and breadth of the teaching experiences afforded to PGY-1 pharmacy residents. A 20-question survey was distributed electronically to 868 American Society of Health-System Pharmacists-accredited PGY-1 residency program directors. The survey was completed by 322 program directors. Developing pharmacy educators was found to be highly valued by 57% of the program directors. Advertisement of teaching opportunities was found to be statistically significant when comparing program directors with a high perceived value for providing teaching opportunities to program demographics. Statistically significant differences were identified associating development of a teaching portfolio, evaluation of Advanced Pharmacy Practice Experiences students, and delivery of didactic lectures with program directors who highly value developing pharmacy educators. Future residency candidates interested in teaching or a career in academia may utilize these findings to identify programs that are more likely to value developing pharmacy educators. The implementation of a standardized teaching experience among all programs may be difficult. © The Author(s) 2015.

Monoanionic molybdenum and tungsten tris(dithiolene) complexes: a multifrequency EPR study.

PubMed

Sproules, Stephen; Banerjee, Priyabrata; Weyhermüller, Thomas; Yan, Yong; Donahue, James P; Wieghardt, Karl

2011-08-01

Numerous Mo and W tris(dithiolene) complexes in varying redox states have been prepared and representative examples characterized crystallographically: [M(S(2)C(2)R(2))(3)](z) [M = Mo, R = Ph, z = 0 (1) or 1- (2); M = W, R = Ph, z = 0 (4) or 1- (5); R = CN, z = 2-, M = Mo (3) or W (6)]. Changes in dithiolene C-S and C-C bond lengths for 1 versus 2 and 4 versus 5 are indicative of ligand reduction. Trigonal twist angles (Θ) and dithiolene fold angles (α) increase and decrease, respectively, for 2 versus 1, 5 versus 4. Cyclic voltammetry reveals generally two reversible couples corresponding to 0/1- and 1-/2- reductions. The electronic structures of monoanionic molybdenum tris(dithiolene) complexes have been analyzed by multifrequency (S-, X-, Q-band) EPR spectroscopy. Spin-Hamiltonian parameters afforded by spectral simulation for each complex demonstrate the existence of two distinctive electronic structure types. The first is [Mo(IV)((A)L(3)(5-•))](1-) ((A)L = olefinic dithiolene, type A), which has the unpaired electron restricted to the tris(dithiolene) unit and is characterized by isotropic g-values and small molybdenum superhyperfine coupling. The second is formulated as [Mo(V)((B)L(3)(6-))](1-) ((B)L = aromatic dithiolene, type B) with spectra distinguished by a prominent g-anisotropy and hyperfine coupling consistent with the (d(z(2)))(1) paramagnet. The electronic structure disparity is also manifested in their electronic absorption spectra. The compound [W(bdt)(3)](1-) exhibits spin-Hamiltonian parameters similar to those of [Mo(bdt)(3)](1-) and thus is formulated as [W(V)((B)L(3)(6-))](1-). The EPR spectra of [W((A)L(3))](1-) display spin-Hamiltonian parameters that suggest their electronic structure is best represented by two resonance forms {[W(IV)((A)L(3)(5-•))](1-) ↔ [W(V)((A)L(3)(6-))](1-)}. The contrast with the corresponding [Mo(IV)((A)L(3)(5-•))](1-) complexes highlights tungsten's preference for higher oxidation states. © 2011 American Chemical Society

Isolation, characterization, and computational studies of the novel [Mo3(mu3-Br)2(mu-Br)3Br6]2- cluster anion.

PubMed

Paraskevopoulou, Patrina; Makedonas, Christodoulos; Psaroudakis, Nikolaos; Mitsopoulou, Christiana A; Floros, Georgios; Seressioti, Andriana; Ioannou, Marinos; Sanakis, Yiannis; Rath, Nigam; Gómez García, Carlos J; Stavropoulos, Pericles; Mertis, Konstantinos

2010-03-01

The novel trimolybdenum cluster [Mo(3)(mu(3)-Br)(2)(mu-Br)(3)Br(6)](2-) (1, {Mo(3)}(9+), 9 d-electrons) has been isolated from the reaction of [Mo(CO)(6)] with 1,2-C(2)H(4)Br(2) in refluxing PhCl. The compound has been characterized in solution by electrospray ionization mass spectrometry (ESI-MS), UV-vis spectroscopy, cyclic voltammetry, and in the solid state by X-ray analysis (counter-cations: (n-Bu)(4)N(+) (1), Et(4)N(+), Et(3)BzN(+)), electron paramagnetic resonance (EPR), magnetic susceptibility measurements, and infrared spectroscopy. The least disordered (n-Bu)(4)N(+) salt crystallizes in the monoclinic space group C2/c, a = 20.077(2) A, b = 11.8638(11) A, c = 22.521(2) A, alpha = 90 deg, beta = 109.348(4) deg, gamma = 90 deg, V = 5061.3(9) A(3), Z = 4 and contains an isosceles triangular metal arrangement, which is capped by two bromine ligands. Each edge of the triangle is bridged by bromine ions. The structure is completed by six terminal bromine ligands. According to the magnetic measurements and the EPR spectrum the trimetallic core possesses one unpaired electron. Electrochemical data show that oxidation by one electron of 1 is reversible, thus proceeding with retention of the trimetallic core, while the reduction is irreversible. The effective magnetic moment of 1 (mu(eff), 1.55 mu(B), r.t.) is lower than the spin-only value (1.73 mu(B)) for S = 1/2 systems, most likely because of high spin-orbit coupling of Mo(III) and/or magnetic coupling throughout the lattice. The ground electronic state of 1 was studied using density functional theory techniques under the broken symmetry formalism. The ground state is predicted to exhibit strong antiferromagnetic coupling between the three molybdenum atoms of the core. Moreover, our calculated data predict two broken symmetry states that differ only by 0.4 kcal/mol (121 cm(-1)). The antiferromagnetic character is delocalized over three magnetic orbitals populated by three electrons. The assignment of the infrared spectra is also provided.

Effect of modest pay-for-performance financial incentive on time-to-discharge summary dictation among medical residents.

PubMed

Wolk, Adam; Wang, Erwin; Horak, Bernard; Cloonan, Patricia; Adams, Michael; Moore, Eileen; Jaipaul, Chitra Komal; Brown, Gabrielle; Dasgupta, Dabanjan; Deluca, Danielle; Grossman, Mila

2013-01-01

Evaluate the effect of a modest financial incentive on time-to-discharge summary dictation among medicine residents. Pay-for-performance incentives are used in a number of health care settings. Studies are lacking on their use with medical residents and other trainees. Timely completion of discharge summaries is necessary for effective follow-up after hospitalization, and residents perform the majority of discharge summary dictations in academic medical centers. Medicine residents with the lowest average discharge-to-dictation time during their 1-month inpatient medicine ward rotation were rewarded with a $50 gift card. Discharge data were captured using an autopopulating electronic database. The average discharge-to-dictation time was reduced from 7.44 to 1.84 days, representing a 75.3% decrease. Almost 90% of discharge summary dictations were performed on the day of discharge. A modest financial incentive resulted in a marked improvement in the time-to-discharge summary dictation by medicine residents. Pay-for-performance programs may be an effective strategy for improving the quality and efficiency of patient care in academic medical centers.

The Internet School of Medicine: use of electronic resources by medical trainees and the reliability of those resources.

PubMed

Egle, Jonathan P; Smeenge, David M; Kassem, Kamal M; Mittal, Vijay K

2015-01-01

Electronic sources of medical information are plentiful, and numerous studies have demonstrated the use of the Internet by patients and the variable reliability of these sources. Studies have investigated neither the use of web-based resources by residents, nor the reliability of the information available on these websites. A web-based survey was distributed to surgical residents in Michigan and third- and fourth-year medical students at an American allopathic and osteopathic medical school and a Caribbean allopathic school regarding their preferred sources of medical information in various situations. A set of 254 queries simulating those faced by medical trainees on rounds, on a written examination, or during patient care was developed. The top 5 electronic resources cited by the trainees were evaluated for their ability to answer these questions accurately, using standard textbooks as the point of reference. The respondents reported a wide variety of overall preferred resources. Most of the 73 responding medical trainees favored textbooks or board review books for prolonged studying, but electronic resources are frequently used for quick studying, clinical decision-making questions, and medication queries. The most commonly used electronic resources were UpToDate, Google, Medscape, Wikipedia, and Epocrates. UpToDate and Epocrates had the highest percentage of correct answers (47%) and Wikipedia had the lowest (26%). Epocrates also had the highest percentage of wrong answers (30%), whereas Google had the lowest percentage (18%). All resources had a significant number of questions that they were unable to answer. Though hardcopy books have not been completely replaced by electronic resources, more than half of medical students and nearly half of residents prefer web-based sources of information. For quick questions and studying, both groups prefer Internet sources. However, the most commonly used electronic resources fail to answer clinical queries more than half of the time and have an alarmingly high rate of inaccurate information. Copyright © 2014 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Electronic Medical Record and Quality Ratings of Long Term Care Facilities Long-Term Care Facility Characteristics and Reasons and Barriers for Adoption of Electronic Medical Record

ERIC Educational Resources Information Center

Daniels, Cheryl Andrea

2013-01-01

With the growing elderly population, compounded by the retirement of the babyboomers, the need for long-term care (LTC) facilities is expected to grow. An area of great concern for those that are seeking a home for their family member is the quality of care provided by the nursing home to the residents. Electronic medical records (EMR) are often…

Classroom Research: Writing Assessment in Paired and Separate History and English Classes.

ERIC Educational Resources Information Center

Messina, Susan; White, Diane

In fall 1991, Solano Community College (California) undertook a study comparing the writing skills of students in an integrated course combining history and freshman English composition with students in unpaired history and English classes. Students were divided into three groups: the integrated class and two control groups, one taking history…

Long-lived nanosecond spin relaxation and spin coherence of electrons in monolayer MoS 2 and WS 2

DOE PAGES

Yang, Luyi; Sinitsyn, Nikolai A.; Chen, Weibing; ...

2015-08-03

The recently discovered monolayer transition metal dichalcogenides (TMDCs) provide a fertile playground to explore new coupled spin–valley physics. Although robust spin and valley degrees of freedom are inferred from polarized photoluminescence (PL) experiments PL timescales are necessarily constrained by short-lived (3–100 ps) electron–hole recombination9, 10. Direct probes of spin/valley polarization dynamics of resident carriers in electron (or hole)-doped TMDCs, which may persist long after recombination ceases, are at an early stage. Here we directly measure the coupled spin–valley dynamics in electron-doped MoS 2 and WS 2 monolayers using optical Kerr spectroscopy, and reveal very long electron spin lifetimes, exceeding 3more » ns at 5 K (2-3 orders of magnitude longer than typical exciton recombination times). In contrast with conventional III–V or II–VI semiconductors, spin relaxation accelerates rapidly in small transverse magnetic fields. Supported by a model of coupled spin–valley dynamics, these results indicate a novel mechanism of itinerant electron spin dephasing in the rapidly fluctuating internal spin–orbit field in TMDCs, driven by fast inter-valley scattering. Additionally, a long-lived spin coherence is observed at lower energies, commensurate with localized states. These studies provide insight into the physics underpinning spin and valley dynamics of resident electrons in atomically thin TMDCs.« less

Localization of spindle checkpoint proteins in cells undergoing mitosis with unreplicated genomes.

PubMed

Johnson, Mary Kathrine; Cooksey, Amanda M; Wise, Dwayne A

2008-11-01

CHO cells can be arrested with hydoxyurea at the beginning of the DNA synthesis phase of the cell cycle. Subsequent treatment with the xanthine, caffeine, induces cells to bypass the S-phase checkpoint and enter unscheduled mitosis [Schlegel and Pardee,1986, Science 232:1264-1266]. These treated cells build a normal spindle and distribute kinetochores, unattached to chromosomes, to their daughter cells [Brinkley et al.,1988, Nature 336:251-254; Zinkowski et al.,1991, J Cell Biol 113:1091-1110; Wise and Brinkley,1997, Cell Motil Cytoskeleton 36:291-302; Balczon et al.,2003, Chromosoma 112:96-102]. To investigate how these cells distribute kinetochores to daughter cells, we analyzed the spindle checkpoint components, Mad2, CENP-E, and the 3F3 phosphoepitope, using immunofluorescence and digital microscopy. Even though the kinetochores were unpaired and DNA was fragmented, the tension, alignment, and motor components of the checkpoint were found to be present and localized as predicted in prometaphase and metaphase. This unusual mitosis proves that a cell can successfully localize checkpoint proteins and divide even when kinetochores are unpaired and fragmented. (c) 2008 Wiley-Liss, Inc.

Stabilised DNA secondary structures with increasing transcription localise hypermutable bases for somatic hypermutation in IGHV3-23.

PubMed

Duvvuri, Bhargavi; Duvvuri, Venkata R; Wu, Jianhong; Wu, Gillian E

2012-07-01

Somatic hypermutation (SHM) mediated by activation-induced cytidine deaminase (AID) is a transcription-coupled mechanism most responsible for generating high affinity antibodies. An issue remaining enigmatic in SHM is how AID is preferentially targeted during transcription to hypermutable bases in its substrates (WRC motifs) on both DNA strands. AID targets only single stranded DNA. By modelling the dynamical behaviour of IGHV3-23 DNA, a commonly used human variable gene segment, we observed that hypermutable bases on the non-transcribed strand are paired whereas those on transcribed strand are mostly unpaired. Hypermutable bases (both paired and unpaired) are made accessible to AID in stabilised secondary structures formed with increasing transcription levels. This observation provides a rationale for the hypermutable bases on both the strands of DNA being targeted to a similar extent despite having differences in unpairedness. We propose that increasing transcription and RNAP II stalling resulting in the formation and stabilisation of stem-loop structures with AID hotspots in negatively supercoiled region can localise the hypermutable bases of both strands of DNA, to AID-mediated SHM.

Mathematical analysis of endothelial sibling pair cell-cell interactions using time-lapse cinematography data.

PubMed

Brown, L M; Ryan, U S; Absher, M; Olazabal, B M

1982-01-01

The sibling pairs from two different endothelial cell cultures were analysed by time-lapse cinematography. It was shown that wounded and regular (low density seeded) cultures differed in the behaviour patterns of their siblings. The cultures differed most significantly in the minimum interdivision time (IDT) which was 27% lower for the wounded culture. In the wounded culture there was a greater correlation of IDT values between sibling pairs. IDT values recorded both for paired and for unpaired cells were shorter for the wounded than for the regular culture. The mean IDT for unpaired cells was longer than the mean IDT for paired cells in the regular culture. Thus paired cells in the regular culture, had shorter IDTs, but not as short as in the wounded culture. It was significant that in the wounded culture the first generation of siblings were very close (less than 150 microns apart) at division. Overall the behaviour differences between the two cultures resulted in a higher rate of increase in cell numbers, and thus faster repair, of the wounded monolayer.

Acquired appetitive responding to intravenous nicotine reflects a Pavlovian conditioned association

PubMed Central

Murray, Jennifer E.; Bevins, Rick A.

2008-01-01

Recent research examining Pavlovian appetitive conditioning has extended the associative properties of nicotine from the unconditioned stimulus or reward to include the role of a conditional stimulus (CS), capable of acquiring the ability to evoke a conditioned response. To date, published research has used pre-session extravascular injections to examine nicotine as a contextual CS in that appetitive Pavlovian drug discrimination task. Two studies in the current research examined whether a nicotine CS can function discretely, multiple times within a session using passive intravenous infusions. In Experiment 1, rats readily acquired a discrimination in conditioned responding between nicotine and saline infusions when nicotine was selectively paired with sucrose presentations. In Experiment 2, rats were either trained with nicotine paired with sucrose or explicitly unpaired with sucrose. The results showed that rats trained with explicitly unpaired nicotine and sucrose did not increase dipper entries after the infusions. Nicotine was required to be reliably paired with sucrose for control of conditioned responding to develop. Implications of these findings are discussed in relation to tobacco addiction, learning theory, and pharmacology. PMID:19170434

Emotional intelligence in orthopedic surgery residents.

PubMed

Chan, Kevin; Petrisor, Brad; Bhandari, Mohit

2014-04-01

Emotional intelligence (EI) is the ability to understand and manage emotions in oneself and others. It was originally popularized in the business literature as a key attribute for success that was distinct from cognitive intelligence. Increasing focus is being placed on EI in medicine to improve clinical and academic performance. Despite the proposed benefits, to our knowledge, there have been no previous studies on the role of EI in orthopedic surgery. We evaluated baseline data on EI in a cohort of orthopedic surgery residents. We asked all orthopedic surgery residents at a single institution to complete an electronic version of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). We used completed questionnaires to calculate total EI scores and 4 branch scores. Data were analyzed according to a priori cutoff values to determine the proportion of residents who were considered competent on the test. Data were also analyzed for possible associations with age, sex, race and level of training. Thirty-nine residents (100%) completed the MSCEIT. The mean total EI score was 86 (maximum score 145). Only 4 (10%) respondents demonstrated competence in EI. Junior residents (p = 0.026), Caucasian residents (p = 0.009) and those younger than 30 years (p = 0.008) had significantly higher EI scores. Our findings suggest that orthopedic residents score low on EI based on the MSCEIT. Optimizing resident competency in noncognitive skills may be enhanced by dedicated EI education, training and testing.

The pregnant female surgical resident

PubMed Central

Shifflette, Vanessa; Hambright, Susannah; Amos, Joseph Darryl; Dunn, Ernest; Allo, Maria

2018-01-01

Background Surgery continues to be an intense, time-consuming residency. Many medical students decide against surgery as a profession due to the long work hours and family strain. The pregnant female surgical resident has an added stress factor compared to her male counterpart. Methods We distributed an electronic, online 26-question survey to 32 general surgery programs in the southwestern region of the United States. Each program distributed our survey to the female surgical residents who had been pregnant during residency in the last 5 years. Each program was re-contacted 6 weeks after the initial contact. Most questions were in a 5-point Likert scale format. The responses were collected and analyzed using the Survey Monkey website. Results An unvalidated survey was sent to 32 general surgery programs and 26 programs responded (81%). Each program was asked for the total number of possible responses from female residents that met our criteria (60 female residents). Seven of the programs (27%) stated that they have had zero residents pregnant. We had 22 residents respond (37%). Over half of the residents (55%) were pregnant during their 2nd or 3rd year of residency, with only 18% pregnant during a research year. Thirty-one percent had a lower American Board of Surgery In-Training Exam (ABSITE) score. Ninety percent of the residents were able to take 4 weeks or more for maternity leave. Most of the residents (95%) stated that they would do this again during residency given the opportunity, but many of the residents felt that returning back to work with a child at home was the most difficult part. Conclusion Our preliminary study shows that the programs surveyed were accommodating to the female surgical resident. Nevertheless, despite adequate support from their program and an overall positive experience, many residents indicated that they had a decline in their education and performance. PMID:29785149

The Pocket Psychiatrist: Tools to enhance psychiatry education in family medicine.

PubMed

Bass, Deanna; Brandenburg, Dana; Danner, Christine

2015-01-01

Primary care is the setting where the majority of patients seek assistance for their mental health problems. To assist family medicine residents in providing effective care to patients for mental health problems during residency and after graduation, it is essential they receive training in the assessment, diagnosis, and treatment of common mental health conditions. While there is some limited education time with a psychiatrist in our department, residents need tools and resources that provide education during their continuity clinics even when the psychiatrist is not available. Information on two tools that were developed is provided. These tools include teaching residents a brief method for conducting a psychiatric interview as well as a means to access evidence-based information on diagnosis and treatment of mental health conditions through templates available within our electronic medical record. © The Author(s) 2015.

Dinitrosyl iron complexes with thiolate ligands: physico-chemistry, biochemistry and physiology.

PubMed

Vanin, Anatoly F

2009-08-01

Some present-day concepts on the origin and functional activities of dinitrosyl iron complexes (DNIC) with thiolate ligands are considered. Nitric oxide (NO) including to DNIC increases its stability and ensures effective targeting of NO to organs and tissues. DNIC have a square-planar structure; unpaired electron is localized on the d(z2) orbital of the d(7) iron atom. The formula of DNIC appears as [(RS(-))(2)Fe(+)(NO(+))(2)....((-)SR)(2)](-); electron spin is S=1/2. Conversion of an originally diamagnetic group, Fe(2+)(NO)(2) with electron configuration d(8), into a paramagnetic Fe(+)(NO(+))(2) group is a result of disproportionation of NO ligands and substitution of newly generated NO(-) for NO. The nitrosonium ions present in DNIC impart to them high nitrosylating activity, e.g., ability to induce S-nitrosylation of thiols. The ability of S-nitrosothiols to form DNIC in a direct reaction with bivalent iron is a prerequisite to effective mutual conversions of DNIC and S-nitrosothiols. In this work, I consider some mechanisms of destructive effects of low-molecular DNIC on active centers of iron-sulfur proteins, ability of DNIC to express certain genes, to activate guanylate cyclase, to exert hypotensive, vasodilator effects, to inhibit platelet aggregation, to accelerate wound healing and to produce potent erective action. Recently a stabilized powder-like polymeric composition based on dimeric glutathione DNIC the water-soluble polymer in which was used as a filling agent was designed. The advantages of this stable DNIC-glutathione preparation include their ability to retain their physico-chemical and functional activities within at least one year. At present, the preparation undergo testing as a base for the design of a wide variety of broad-spectrum drugs.

Velocity modulation spectroscopy of molecular ions II: The millimeter/submillimeter-wave spectrum of TiF + ( X3Φr)

NASA Astrophysics Data System (ADS)

Halfen, D. T.; Ziurys, L. M.

2006-11-01

The pure rotational spectrum of the molecular ion TiF + in its 3Φr ground state has been measured in the range 327-542 GHz using millimeter-wave direct absorption techniques combined with velocity modulation spectroscopy. TiF + was made in an AC discharge from a mixture of TiCl 4, F 2 in He, and argon. Ten transitions of this ion were recorded. In every transition, fluorine hyperfine interactions, as well as the fine structure splittings, were resolved. The fine structure pattern was found to be regular with almost equal spacing in frequency between the three spin components, in contrast to TiCl +, which is perturbed in the ground state. The data were fit with a case ( a) Hamiltonian and rotational, fine structure, and hyperfine constants were determined. The bond length established for TiF +, r0 = 1.7775 Å, was found to be shorter than that of TiF, r0 = 1.8342 Å—also established from mm-wave data. The hyperfine parameters determined are consistent with a δ1π1 electron configuration with the electrons primarily located on the titanium nucleus. The nuclear spin-orbit constant a indicates that the unpaired electrons are closer to the fluorine nucleus in TiF + relative to TiF, as expected with the decrease in bond length for the ion. The shorter bond distance is thought to arise from increased charge on the titanium nucleus as a result of a Ti 2+F - configuration. A similar decrease in bond length was found for TiCl + relative to TiCl.

Organozinc Precursor-Derived Crystalline ZnO Nanoparticles: Synthesis, Characterization and Their Spectroscopic Properties

PubMed Central

Wicker, Susanne; Wang, Xiao; Erichsen, Egil Severin; Fu, Feng

2018-01-01

Crystalline ZnO-ROH and ZnO-OR (R = Me, Et, iPr, nBu) nanoparticles (NPs) have been successfully synthesized by the thermal decomposition of in-situ-formed organozinc complexes Zn(OR)2 deriving from the reaction of Zn[N(SiMe3)2]2 with ROH and of the freshly prepared Zn(OR)2 under an identical condition, respectively. With increasing carbon chain length of alkyl alcohol, the thermal decomposition temperature and dispersibility of in-situ-formed intermediate zinc alkoxides in oleylamine markedly influenced the particle sizes of ZnO-ROH and its shape (sphere, plate-like aggregations), while a strong diffraction peak-broadening effect is observed with decreasing particle size. For ZnO-OR NPs, different particle sizes and various morphologies (hollow sphere or cuboid-like rod, solid sphere) are also observed. As a comparison, the calcination of the fresh-prepared Zn(OR)2 generated ZnO-R NPs possessing the particle sizes of 5.4~34.1 nm. All crystalline ZnO nanoparticles are characterized using X-ray diffraction analysis, electron microscopy and solid-state 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The size effect caused by confinement of electrons’ movement and the defect centres caused by unpaired electrons on oxygen vacancies or ionized impurity heteroatoms in the crystal lattices are monitored by UV-visible spectroscopy, electron paramagnetic resonance (EPR) and photoluminescent (PL) spectroscopy, respectively. Based on the types of defects determined by EPR signals and correspondingly defect-induced probably appeared PL peak position compared to actual obtained PL spectra, we find that it is difficult to establish a direct relationship between defect types and PL peak position, revealing the complication of the formation of defect types and photoluminescence properties. PMID:29300343

Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes

NASA Astrophysics Data System (ADS)

Neelakantan, M. A.; Rusalraj, F.; Dharmaraja, J.; Johnsonraja, S.; Jeyakumar, T.; Sankaranarayana Pillai, M.

2008-12-01

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) L-alanine (ala), L-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N 2O 2 donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, 1H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300 K and in frozen DMSO (77 K) indicate the presence of the unpaired electron in the d orbital. The evaluated metal-ligand bonding parameters showed strong in-plane σ- and π-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5 V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.

Time-resolved luminescence measurements of the magnetic field effect on paramagnetic photosensitizers in photodynamic reactions

NASA Astrophysics Data System (ADS)

Mermut, O.; Bouchard, J.-P.; Cormier, J.-F.; Desroches, P.; Diamond, K. R.; Fortin, M.; Gallant, P.; Leclair, S.; Marois, J.-S.; Noiseux, I.; Morin, J.-F.; Patterson, M. S.; Vernon, M.

2008-02-01

The development of multimodal molecular probes and photosensitizing agents for use in photodynamic therapy (PDT) is vital for optimizing and monitoring cytotoxic responses. We propose a combinatorial approach utilizing photosensitizing molecules that are both paramagnetic and luminescent with multimodal functionality to perturb, control, and monitor molecular-scale reaction pathways in PDT. To this end, a time-domain single photon counting lifetime apparatus with a 400 nm excitation source has been developed and integrated with a variable low field magnet (0- 350mT). The luminescence lifetime decay function was measured in the presence of a sweeping magnetic field for a custom designed photosensitizing molecule in which photoinduced electron transfer was studied The photosensitizer studied was a donor-acceptor complex synthesized using a porphyrin linked to a fullerene molecule. The magneto-optic properties were investigated for the free-base photosensitizer complex as well as those containing either diamagnetic (paired electron) or paramagnetic (unpaired electron) metal centers, Zn(II) and Cu(II). The magnetic field was employed to affect and modify the spin states of radical pairs of the photosensitizing agents via magnetically induced hyperfine and Zeeman effects. Since the Type 1 reaction pathway of an excited triplet state photosensitizer involves the production of radical species, lifetime measurements were conducted at low dissolved oxygen concentration (0.01ppm) to elucidate the dependence of the magnetic perturbation on the photosensitization mechanistic pathway. To optimize the magnetic response, a solvent study was performed examining the dependence of the emission properties on the magnetic field in solutions of varying dielectric constants. Lastly, the cytotoxicity in murine tumor cell suspensions was investigated for the novel porphyrin-fullerene complex by inducing photodynamic treatments and determining the associated cell survival.

Interest in rural medicine among osteopathic residents and medical students.

PubMed

Colegrove, Dustin J; Whitacre, Brian E

2009-01-01

This study examines US osteopathic residents' and medical students' attitudes and willingness to practice in rural medicine. The multiple aims of this study were to determine: (1) if there are any significant differences in interest in rural medicine among various levels of training; (2) the relative age, gender, and race of those who are intending to pursue a career in rural health; and (3) whether a number of demographic characteristics (age, race, year of study) or participation in a rural elective significantly impacted the students' and residents' interest in practicing in a rural area. In particular, differences between osteopathic students and residents are emphasized, because few previous studies have focused on this topic. De-identified, cross-sectional, descriptive techniques utilizing 2 distinct web-based electronic surveys were used in this study. Each survey was sent electronically to medical students and physicians-in-training. Statistical methods included means, frequencies, and t-tests to determine significant differences among groups. Logistic regression was used to determine the impact of various factors on overall rural interest for each group. A total of 161 students from two osteopathic colleges completed and submitted the survey as well as 51 residents/fellows from a variety of training programs. Approximately 43% of the student respondents and 67% of residents expressed an intention of practicing rural medicine. Several notable differences were found among the opinions of students and residents, particularly regarding the perceived prestige of rural physicians. Among medical students, overall interest in rural practice decreased in years 2 to 4; however, there was a positive influence if the students were aged 34 years or over. As expected, being raised in a rural area had a positive impact on rural interest. Additional findings included the lack of significance for gender or race, and the positive influence of taking a rural elective. For residents, some results are similar, although interest in rural medicine actually increased with time. It is imperative that osteopathic medical schools recruit individuals who will be most likely to pursue rural medicine, and then train them to provide health access for rural populations. Further, financial incentives are important to both students and residents, suggesting that 'loan forgiveness' programs or scholarships may be useful in promoting rural location. In order to facilitate the training of individuals who will likely pursue rural medicine, there must be institutional dedication to this goal.

Barriers to advancement in academic surgery: views of senior residents and early career faculty.

PubMed

Cochran, Amalia; Elder, William B; Crandall, Marie; Brasel, Karen; Hauschild, Tricia; Neumayer, Leigh

2013-11-01

A significant faculty attrition rate exists in academic surgery. The authors hypothesized that senior residents and early-career faculty members have different perceptions of advancement barriers in academic surgery. A modified version of the Career Barriers Inventory-Revised was administered electronically to surgical residents and early-career surgical faculty members at 8 academic medical centers. Residents identified a lack of mentorship as a career barrier about half as often as faculty members. Residents were twice as likely as faculty members to view childbearing as a career barrier. Many early-career faculty members cite a lack of mentors as a limitation to their career development in academic surgery. Childbearing remains a complex perceived influence for female faculty members in particular. Female faculty members commonly perceive differential treatment and barriers on the basis of their sex. Faculty development programs should address both systemic and sex-specific obstacles if academic surgery is to remain a vibrant field. Copyright © 2013 Elsevier Inc. All rights reserved.

Transforming the Primary Care Training Clinic: New York State's Hospital Medical Home Demonstration Pilot.

PubMed

Angelotti, Marietta; Bliss, Kathryn; Schiffman, Dana; Weaver, Erin; Graham, Laura; Lemme, Thomas; Pryor, Veronica; Gesten, Foster C

2015-06-01

Training in patient-centered medical home (PCMH) settings may prepare new physicians to measure quality of care, manage the health of populations, work in teams, and include cost information in decision making. Transforming resident clinics to PCMHs requires funding for additional staff, electronic health records, training, and other resources not typically available to residency programs. Describe how a 1115 Medicaid waiver was used to transform the majority of primary care training sites in New York State to the PCMH model and improve the quality of care provided. The 2013-2014 Hospital Medical Home Program provided awards to 60 hospitals and 118 affiliated residency programs (training more than 5000 residents) to transform outpatient sites into PCMHs and provide high-quality, coordinated care. Site visits, coaching calls, resident surveys, data reporting, and feedback were used to promote and monitor change in resident continuity and quality of care. Descriptive analyses measured improvements in these areas. A total of 156 participating outpatient sites (100%) received PCMH recognition. All sites enhanced resident education using PCMH principles through patient empanelment, development of quality dashboards, and transforming resident scheduling and training. Clinical quality outcomes showed improvement across the demonstration, including better performance on colorectal and breast cancer screening rates (rate increases of 13%, P≤.001, and 11%, P=.011, respectively). A 1115 Medicaid waiver is a viable mechanism for states to transform residency clinics to reflect new primary care models. The PCMH transformation of 156 sites led to improvements in resident continuity and clinical outcomes.

Resident duty hours in Canada: a survey and national statement

PubMed Central

2014-01-01

Physicians in general, and residents in particular, are adapting to duty schedules in which they have fewer continuous work hours; however, there are no Canadian guidelines on duty hours restrictions. To better inform resident duty hour policy in Canada, we set out to prepare a set of recommendations that would draw upon evidence reported in the literature and reflect the experiences of resident members of the Canadian Association of Internes and Residents (CAIR). A survey was prepared and distributed electronically to all resident members of CAIR. A total of 1796 eligible residents participated in the survey. Of those who responded, 38% (601) reported that they felt they could safely provide care for up to 16 continuous hours, and 20% (315) said that 12 continuous hours was the maximum period during which they could safely provide care (n = 1592). Eighty-two percent (1316) reported their perception that the quality of care they had provided suffered because of the number of consecutive hours worked (n = 1598). Only 52% (830) had received training in handover (n = 1594); those who had received such training reported that it was commonly provided through informal modelling. On the basis of these data and the existing literature, CAIR recommends that resident duty hours be managed in a way that does not endanger the health of residents or patients; does not impair education; is flexible; and does not violate ethical or legal standards. Further, residents should be formally trained in handover skills and alternative duty hour models. PMID:25559388

Resident duty hours in Canada: a survey and national statement.

PubMed

Masterson, Mark F; Shrichand, Pankaj; Maniate, Jerry M

2014-01-01

Physicians in general, and residents in particular, are adapting to duty schedules in which they have fewer continuous work hours; however, there are no Canadian guidelines on duty hours restrictions. To better inform resident duty hour policy in Canada, we set out to prepare a set of recommendations that would draw upon evidence reported in the literature and reflect the experiences of resident members of the Canadian Association of Internes and Residents (CAIR). A survey was prepared and distributed electronically to all resident members of CAIR. A total of 1796 eligible residents participated in the survey. Of those who responded, 38% (601) reported that they felt they could safely provide care for up to 16 continuous hours, and 20% (315) said that 12 continuous hours was the maximum period during which they could safely provide care (n=1592). Eighty-two percent (1316) reported their perception that the quality of care they had provided suffered because of the number of consecutive hours worked (n=1598). Only 52% (830) had received training in handover (n=1594); those who had received such training reported that it was commonly provided through informal modelling. On the basis of these data and the existing literature, CAIR recommends that resident duty hours be managed in a way that does not endanger the health of residents or patients; does not impair education; is flexible; and does not violate ethical or legal standards. Further, residents should be formally trained in handover skills and alternative duty hour models.

Impact of target mRNA structure on siRNA silencing efficiency: A large-scale study.

PubMed

Gredell, Joseph A; Berger, Angela K; Walton, S Patrick

2008-07-01

The selection of active siRNAs is generally based on identifying siRNAs with certain sequence and structural properties. However, the efficiency of RNA interference has also been shown to depend on the structure of the target mRNA, primarily through studies using exogenous transcripts with well-defined secondary structures in the vicinity of the target sequence. While these studies provide a means for examining the impact of target sequence and structure independently, the predicted secondary structures for these transcripts are often not reflective of structures that form in full-length, native mRNAs where interactions can occur between relatively remote segments of the mRNAs. Here, using a combination of experimental results and analysis of a large dataset, we demonstrate that the accessibility of certain local target structures on the mRNA is an important determinant in the gene silencing ability of siRNAs. siRNAs targeting the enhanced green fluorescent protein were chosen using a minimal siRNA selection algorithm followed by classification based on the predicted minimum free energy structures of the target transcripts. Transfection into HeLa and HepG2 cells revealed that siRNAs targeting regions of the mRNA predicted to have unpaired 5'- and 3'-ends resulted in greater gene silencing than regions predicted to have other types of secondary structure. These results were confirmed by analysis of gene silencing data from previously published siRNAs, which showed that mRNA target regions unpaired at either the 5'-end or 3'-end were silenced, on average, approximately 10% more strongly than target regions unpaired in the center or primarily paired throughout. We found this effect to be independent of the structure of the siRNA guide strand. Taken together, these results suggest minimal requirements for nucleation of hybridization between the siRNA guide strand and mRNA and that both mRNA and guide strand structure should be considered when choosing candidate siRNAs. (c) 2008 Wiley Periodicals, Inc.

Dynamics of linker residues modulate the nucleic acid binding properties of the HIV-1 nucleocapsid protein zinc fingers.

PubMed

Zargarian, Loussiné; Tisné, Carine; Barraud, Pierre; Xu, Xiaoqian; Morellet, Nelly; René, Brigitte; Mély, Yves; Fossé, Philippe; Mauffret, Olivier

2014-01-01

The HIV-1 nucleocapsid protein (NC) is a small basic protein containing two zinc fingers (ZF) separated by a short linker. It is involved in several steps of the replication cycle and acts as a nucleic acid chaperone protein in facilitating nucleic acid strand transfers occurring during reverse transcription. Recent analysis of three-dimensional structures of NC-nucleic acids complexes established a new property: the unpaired guanines targeted by NC are more often inserted in the C-terminal zinc finger (ZF2) than in the N-terminal zinc finger (ZF1). Although previous NMR dynamic studies were performed with NC, the dynamic behavior of the linker residues connecting the two ZF domains remains unclear. This prompted us to investigate the dynamic behavior of the linker residues. Here, we collected 15N NMR relaxation data and used for the first time data at several fields to probe the protein dynamics. The analysis at two fields allows us to detect a slow motion occurring between the two domains around a hinge located in the linker at the G35 position. However, the amplitude of motion appears limited in our conditions. In addition, we showed that the neighboring linker residues R29, A30, P31, R32, K33 displayed restricted motion and numerous contacts with residues of ZF1. Our results are fully consistent with a model in which the ZF1-linker contacts prevent the ZF1 domain to interact with unpaired guanines, whereas the ZF2 domain is more accessible and competent to interact with unpaired guanines. In contrast, ZF1 with its large hydrophobic plateau is able to destabilize the double-stranded regions adjacent to the guanines bound by ZF2. The linker residues and the internal dynamics of NC regulate therefore the different functions of the two zinc fingers that are required for an optimal chaperone activity.

Dynamics of Linker Residues Modulate the Nucleic Acid Binding Properties of the HIV-1 Nucleocapsid Protein Zinc Fingers

PubMed Central

Zargarian, Loussiné; Tisné, Carine; Barraud, Pierre; Xu, Xiaoqian; Morellet, Nelly; René, Brigitte; Mély, Yves; Fossé, Philippe; Mauffret, Olivier

2014-01-01

The HIV-1 nucleocapsid protein (NC) is a small basic protein containing two zinc fingers (ZF) separated by a short linker. It is involved in several steps of the replication cycle and acts as a nucleic acid chaperone protein in facilitating nucleic acid strand transfers occurring during reverse transcription. Recent analysis of three-dimensional structures of NC-nucleic acids complexes established a new property: the unpaired guanines targeted by NC are more often inserted in the C-terminal zinc finger (ZF2) than in the N-terminal zinc finger (ZF1). Although previous NMR dynamic studies were performed with NC, the dynamic behavior of the linker residues connecting the two ZF domains remains unclear. This prompted us to investigate the dynamic behavior of the linker residues. Here, we collected 15N NMR relaxation data and used for the first time data at several fields to probe the protein dynamics. The analysis at two fields allows us to detect a slow motion occurring between the two domains around a hinge located in the linker at the G35 position. However, the amplitude of motion appears limited in our conditions. In addition, we showed that the neighboring linker residues R29, A30, P31, R32, K33 displayed restricted motion and numerous contacts with residues of ZF1. Our results are fully consistent with a model in which the ZF1-linker contacts prevent the ZF1 domain to interact with unpaired guanines, whereas the ZF2 domain is more accessible and competent to interact with unpaired guanines. In contrast, ZF1 with its large hydrophobic plateau is able to destabilize the double-stranded regions adjacent to the guanines bound by ZF2. The linker residues and the internal dynamics of NC regulate therefore the different functions of the two zinc fingers that are required for an optimal chaperone activity. PMID:25029439

Impact of target mRNA structure on siRNA silencing efficiency: a large-scale study

PubMed Central

Gredell, Joseph A.; Berger, Angela K.; Walton, S. Patrick

2009-01-01

The selection of active siRNAs is generally based on identifying siRNAs with certain sequence and structural properties. However, the efficiency of RNA interference has also been shown to depend on the structure of the target mRNA, primarily through studies using exogenous transcripts with well-defined secondary structures in the vicinity of the target sequence. While these studies provide a means for examining the impact of target sequence and structure independently, the predicted secondary structures for these transcripts are often not reflective of structures that form in full-length, native mRNAs where interactions can occur between relatively remote segments of the mRNAs. Here, using a combination of experimental results and analysis of a large dataset, we demonstrate that the accessibility of certain local target structures on the mRNA is an important determinant in the gene silencing ability of siRNAs. siRNAs targeting the enhanced green fluorescent protein were chosen using a minimal siRNA selection algorithm followed by classification based on the predicted minimum free energy structures of the target transcripts. Transfection into HeLa and HepG2 cells revealed that siRNAs targeting regions of the mRNA predicted to have unpaired 5’- and 3’-ends resulted in greater gene silencing than regions predicted to have other types of secondary structure. These results were confirmed by analysis of gene silencing data from previously published siRNAs, which showed that mRNA target regions unpaired at either the 5’-end or 3’-end were silenced, on average, ~10% more strongly than target regions unpaired in the center or primarily paired throughout. We found this effect to be independent of the structure of the siRNA guide strand. Taken together, these results suggest minimal requirements for nucleation of hybridization between the siRNA guide strand and mRNA and that both mRNA and guide strand structure should be considered when choosing candidate siRNAs. PMID:18306428

Relief from Back Pain Through Postural Adjustment: a Controlled Clinical Trial of the Immediate Effects of Muscular Chains Therapy (MCT).

PubMed

Rosario, Jose L

2014-09-01

Back pain can be one of the most common health problems, causing suffering, disabilities, and financial losses. Postural models for pain treatment state that poor posture alters the joint position and causes pain, such as back pain. Muscular Chain Therapy (MCT) is a technique that is used to treat posture pathologies, among others. The aim of the present study was to assess the efficiency of a single session of Muscular Chain Therapy (MCT) on complaints of undiagnosed musculoskeletal spinal pain. Physical therapy clinic of the University of Center-West (Guarapuava, Brazil). 100 subjects, aged between 20 and 39 years, with complaints of spinal musculoskeletal pain. Randomized controlled trial. The participants were randomly assigned by a non-care provider into two groups: The MCT Group that received Muscular Chain Treatment and the Control Group that received a placebo treatment of 15 minutes turned off ultrasound therapy. All volunteers were assessed before and after treatment using an analog pain scale. A score of 0 indicated no pain and 10 was the maximum degree of pain on the scale. Degree of pain measured by analog scale. The chi-square goodness of fit test was used to compare gender distribution among groups displayed a p value = .25. Subject age had differences analyzed using the unpaired t test (p = .44). Pain assessment for treatment and placebo control groups was analyzed using a paired t test and unpaired t test. The paired t test was used for intragroup before/after treatment comparison (MCT p = .00001; Control Group p = .0001). The unpaired t test was used for comparing the difference of the pain level before and after treatment between groups (p = .0001). A priori statistical significance was set a p = .05. It is possible to conclude that one MCT session is an effective treatment of undiagnosed spinal musculoskeletal pain.

Implications of current resident work-hour guidelines on the future practice of surgery in Canada.

PubMed

Maruscak, Adam A; VanderBeek, Laura; Ott, Michael C; Kelly, Stephen; Forbes, Thomas L

2012-01-01

Work-hour restrictions have had a profound impact on surgical training. However, little is known of how work-hour restrictions may affect the future practice patterns of current surgical residents. The purpose of this study is to compare the anticipated career practice patterns of surgical residents who are training within an environment of work-hour restrictions with the current practice of faculty surgeons. An electronic survey was sent to all surgery residents and faculty at 2 Canadian university-affiliated medical centers. The survey consisted of questions regarding expected (residents) or current (faculty) practice patterns. A total of 149 residents and 125 faculty members completed the survey (50.3% and 52.3% response rates, respectively). A greater proportion of males were in the faculty cohort than in the resident group (77.6% vs 62.4%, p = 0.0003). More faculty than residents believed that work-hour restrictions have a negative impact on both residency education (40.8% vs 20.8%, p = 0.008) and preparation for a surgical career (56.8% vs 19.5%, p < 0.0001). Compared with current faculty, residents plan to take less call (p < 0.0003), work fewer days of the week (p < 0.0001), are more likely to limit their duty hours on postcall days (p = 0.009), and take parental leave (p = 0.02) once in practice. Male and female residents differed somewhat in their responses in that more female residents plan to limit their postcall duty hours (55.4% vs 36.5%, p = 0.009) and to take a parental leave (51.8% vs 16.1%, p < 0.0001) compared with their male resident colleagues. Current surgical residents expect to adopt components of resident work-hour guidelines into their surgical practices after completing their residency. These practice patterns will have surgical workforce implications and might require larger surgical groups and reconsideration of resource allocation. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Results of the 2013-2015 Association of Residents in Radiation Oncology Survey of Chief Residents in the United States.

PubMed

Nabavizadeh, Nima; Burt, Lindsay M; Mancini, Brandon R; Morris, Zachary S; Walker, Amanda J; Miller, Seth M; Bhavsar, Shripal; Mohindra, Pranshu; Kim, Miranda B; Kharofa, Jordan

2016-02-01

The purpose of this project was to survey radiation oncology chief residents to define their residency experience and readiness for independent practice. During the academic years 2013 to 2014 and 2014 to 2015, the Association of Residents in Radiation Oncology (ARRO) conducted an electronic survey of post-graduate year-5 radiation oncology residents in the United States during the final 3 months of training. Descriptive statistics are reported. Sixty-six chief residents completed the survey in 2013 to 2014 (53% response rate), and 69 completed the survey in 2014 to 2015 (64% response rate). Forty to 85% percent of residents reported inadequate exposure to high-dose rate and low-dose rate brachytherapy. Nearly all residents in both years (>90%) reported adequate clinical experience for the following disease sites: breast, central nervous system, gastrointestinal, genitourinary, head and neck, and lung. However, as few as 56% reported adequate experience in lymphoma or pediatric malignancies. More than 90% of residents had participated in retrospective research projects, with 20% conducting resident-led prospective clinical trials and 50% conducting basic science or translational projects. Most chief residents reported working 60 or fewer hours per week in the clinical/hospital setting and performing fewer than 15 hours per week tasks that were considered to have little or no educational value. There was more than 80% compliance with Accreditation Council for Graduate Medical Education (ACGME) work hour limits. Fifty-five percent of graduating residents intended to join an established private practice group, compared to 25% who headed for academia. Residents perceive the job market to be more competitive than previous years. This first update of the ARRO chief resident survey since the 2007 to 2008 academic year documents US radiation oncology residents' experiences and conditions over a 2-year period. This analysis may serve as a valuable tool for those seeking to improve training of the next generation of oncology leaders. Copyright © 2016 Elsevier Inc. All rights reserved.

Internal Medicine Residents' Perceptions of Team-Based Care and its Educational Value in the Continuity Clinic: A Qualitative Study.

PubMed

Soones, Tacara N; O'Brien, Bridget C; Julian, Katherine A

2015-09-01

In order to teach residents how to work in interprofessional teams, educators in graduate medical education are implementing team-based care models in resident continuity clinics. However, little is known about the impact of interprofessional teams on residents' education in the ambulatory setting. To identify factors affecting residents' experience of team-based care within continuity clinics and the impact of these teams on residents' education. This was a qualitative study of focus groups with internal medicine residents. Seventy-seven internal medicine residents at the University of California San Francisco at three continuity clinic sites participated in the study. Qualitative interviews were audiotaped and transcribed. The authors used a general inductive approach with sensitizing concepts in four frames (structural, human resources, political and symbolic) to develop codes and identify themes. Residents believed that team-based care improves continuity and quality of care. Factors in four frames affected their ability to achieve these goals. Structural factors included communication through the electronic medical record, consistent schedules and regular team meetings. Human resources factors included the presence of stable teams and clear roles. Political and symbolic factors negatively impacted team-based care, and included low staffing ratios and a culture of ultimate resident responsibility, respectively. Regardless of the presence of these factors or resident perceptions of their teams, residents did not see the practice of interprofessional team-based care as intrinsically educational. Residents' experiences practicing team-based care are influenced by many principles described in the interprofessional teamwork literature, including understanding team members' roles, good communication and sufficient staffing. However, these attributes are not correlated with residents' perceptions of the educational value of team-based care. Including residents in interprofessional teams in their clinic may not be sufficient to teach residents how team-based care can enhance their overall learning and future practice.

Brand Name Statin Prescribing in a Resident Ambulatory Practice: Implications for Teaching Cost-Conscious Medicine.

PubMed

Ryskina, Kira L; Pesko, Michael F; Gossey, J Travis; Caesar, Erica Phillips; Bishop, Tara F

2014-09-01

Several national initiatives aim to teach high-value care to residents. While there is a growing body of literature on cost impact of physicians' therapeutic decisions, few studies have assessed factors that influence residents' prescribing practices. We studied factors associated with intensive health care utilization among internal medicine residents, using brand name statin prescribing as a proxy for higher-cost care. We conducted a retrospective, cross-sectional analysis of statin prescriptions by residents at an urban academic internal medicine program, using electronic health record data between July 1, 2010, and June 30, 2011. For 319 encounters by 90 residents, patients were given a brand name statin in 50% of cases. When categorized into quintiles, the bottom quintile of residents prescribed brand name statins in 2% of encounters, while the top quintile prescribed brand name statins in 98% of encounters. After adjusting for potential confounders, including patient characteristics and supervising attending, being in the primary care track was associated with lower odds (odds ratio [OR], 0.38; P  =  .02; 95% confidence interval [CI], 0.16-0.86), and graduating from a medical school with an above-average hospital care intensity index was associated with higher odds of prescribing brand name statins (OR, 1.70; P  =  .049; 95% CI, 1.003-2.88). We found considerable variation in brand name statin prescribing by residents. Medical school attended and residency program type were associated with resident prescribing behavior. Future interventions should raise awareness of these patterns in an effort to teach high-value, cost-conscious care to all residents.

Mental health from the perspective of primary care residents: a pilot survey.

PubMed

Iskandar, Joseph W; Sharma, Taral; Alishayev, Ilya; Mingoia, Joseph; Vance, John Eric; Ali, Rizwan

2014-01-01

Primary care physicians are increasingly providing psychiatric care in the United States. Unfortunately, there is limited learning opportunity or exposure to psychiatry during their residency training. This survey was conducted to assess primary care resident interaction with mental health professionals and their satisfaction, knowledge, preference, and comfort with the delivery of mental health care in primary health care settings. On the basis of available published literature, a 20-question survey was formulated. Following receipt of the institutional review board's approval, these questions were sent via e-mail in February 2012 to internal and family medicine residents (N = 108) at 2 teaching hospitals in southwest Virginia. Analysis of the electronically captured data resulted in a response rate of 32%. Descriptive analysis was used to examine the results. The responses were equally divided among male and female residents and family medicine and internal medicine residents. There were several interesting findings from the survey. No correlations were noted between the gender of residents, type or location of the medical school, or having had a psychiatric rotation during residency and the reported comfort level treating patients with psychiatric illness or the desire to see psychiatric patients in the future. A positive correlation was found between the residents' training level and their belief about the percentage of mental health providers who have mental health problems. The current training model to acclimate primary care residents to the field of mental health appears to have major limitations. RESULTS of this pilot survey can serve as a guide to conduct prospective, multicenter studies to identify and improve psychiatric training for primary care residency programs.

Low power and type II errors in recent ophthalmology research.

PubMed

Khan, Zainab; Milko, Jordan; Iqbal, Munir; Masri, Moness; Almeida, David R P

2016-10-01

To investigate the power of unpaired t tests in prospective, randomized controlled trials when these tests failed to detect a statistically significant difference and to determine the frequency of type II errors. Systematic review and meta-analysis. We examined all prospective, randomized controlled trials published between 2010 and 2012 in 4 major ophthalmology journals (Archives of Ophthalmology, British Journal of Ophthalmology, Ophthalmology, and American Journal of Ophthalmology). Studies that used unpaired t tests were included. Power was calculated using the number of subjects in each group, standard deviations, and α = 0.05. The difference between control and experimental means was set to be (1) 20% and (2) 50% of the absolute value of the control's initial conditions. Power and Precision version 4.0 software was used to carry out calculations. Finally, the proportion of articles with type II errors was calculated. β = 0.3 was set as the largest acceptable value for the probability of type II errors. In total, 280 articles were screened. Final analysis included 50 prospective, randomized controlled trials using unpaired t tests. The median power of tests to detect a 50% difference between means was 0.9 and was the same for all 4 journals regardless of the statistical significance of the test. The median power of tests to detect a 20% difference between means ranged from 0.26 to 0.9 for the 4 journals. The median power of these tests to detect a 50% and 20% difference between means was 0.9 and 0.5 for tests that did not achieve statistical significance. A total of 14% and 57% of articles with negative unpaired t tests contained results with β > 0.3 when power was calculated for differences between means of 50% and 20%, respectively. A large portion of studies demonstrate high probabilities of type II errors when detecting small differences between means. The power to detect small difference between means varies across journals. It is, therefore, worthwhile for authors to mention the minimum clinically important difference for individual studies. Journals can consider publishing statistical guidelines for authors to use. Day-to-day clinical decisions rely heavily on the evidence base formed by the plethora of studies available to clinicians. Prospective, randomized controlled clinical trials are highly regarded as a robust study and are used to make important clinical decisions that directly affect patient care. The quality of study designs and statistical methods in major clinical journals is improving overtime, 1 and researchers and journals are being more attentive to statistical methodologies incorporated by studies. The results of well-designed ophthalmic studies with robust methodologies, therefore, have the ability to modify the ways in which diseases are managed. Copyright © 2016 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Patient care transitions from the emergency department to the medicine ward: evaluation of a standardized electronic signout tool.

PubMed

Gonzalo, Jed D; Yang, Julius J; Stuckey, Heather L; Fischer, Christopher M; Sanchez, Leon D; Herzig, Shoshana J

2014-08-01

To evaluate the impact of a new electronic handoff tool for emergency department to medicine ward patient transfers over a 1-year period. Prospective mixed-methods analysis of data submitted by medicine residents following admitting shifts before and after eSignout implementation. University-based, tertiary-care hospital. Internal medicine resident physicians admitting patients from the emergency department. An electronic handoff tool (eSignout) utilizing automated paging communication and responsibility acceptance without mandatory verbal communication between emergency department and medicine ward providers. (i) Incidence of reported near misses/adverse events, (ii) communication of key clinical information and quality of verbal communication and (iii) characterization of near misses/adverse events. Seventy-eight of 80 surveys (98%) and 1058 of 1388 surveys (76%) were completed before and after eSignout implementation. Compared with pre-intervention, residents in the post-intervention period reported similar number of shifts with a near miss/adverse event (10.3 vs. 7.8%; P = 0.27), similar communication of key clinical information, and improved verbal signout quality, when it occurred. Compared with the former process requiring mandatory verbal communication, 93% believed the eSignout was more efficient and 61% preferred the eSignout. Patient safety issues related to perceived sufficiency/accuracy of diagnosis, treatment or disposition, and information quality. The eSignout was perceived as more efficient and preferred over the mandatory verbal signout process. Rates of reported adverse events were similar before and after the intervention. Our experience suggests electronic platforms with optional verbal communication can be used to standardize and improve the perceived efficiency of patient handoffs. © The Author 2014. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved.

Direct observation of the oxidation of DNA bases by phosphate radicals formed under radiation: a model of the backbone-to-base hole transfer.

PubMed

Ma, Jun; Marignier, Jean-Louis; Pernot, Pascal; Houée-Levin, Chantal; Kumar, Anil; Sevilla, Michael D; Adhikary, Amitava; Mostafavi, Mehran

2018-05-30

In irradiated DNA, by the base-to-base and backbone-to-base hole transfer processes, the hole (i.e., the unpaired spin) localizes on the most electropositive base, guanine. Phosphate radicals formed via ionization events in the DNA-backbone must play an important role in the backbone-to-base hole transfer process. However, earlier studies on irradiated hydrated DNA, on irradiated DNA-models in frozen aqueous solution and in neat dimethyl phosphate showed the formation of carbon-centered radicals and not phosphate radicals. Therefore, to model the backbone-to-base hole transfer process, we report picosecond pulse radiolysis studies of the reactions between H2PO4˙ with the DNA bases - G, A, T, and C in 6 M H3PO4 at 22 °C. The time-resolved observations show that in 6 M H3PO4, H2PO4˙ causes the one-electron oxidation of adenine, guanine and thymine, by forming the cation radicals via a single electron transfer (SET) process; however, the rate constant of the reaction of H2PO4˙ with cytosine is too low (<107 L mol-1 s-1) to be measured. The rates of these reactions are influenced by the protonation states and the reorganization energies of the base radicals and of the phosphate radical in 6 M H3PO4.

Dynamic nuclear polarization of (1)H, (13)C, and (59)Co in a tris(ethylenediamine)cobalt(III) crystalline lattice doped with Cr(III).

PubMed

Corzilius, Björn; Michaelis, Vladimir K; Penzel, Susanne A; Ravera, Enrico; Smith, Albert A; Luchinat, Claudio; Griffin, Robert G

2014-08-20

The study of inorganic crystalline materials by solid-state NMR spectroscopy is often complicated by the low sensitivity of heavy nuclei. However, these materials often contain or can be prepared with paramagnetic dopants without significantly affecting the structure of the crystalline host. Dynamic nuclear polarization (DNP) is generally capable of enhancing NMR signals by transferring the magnetization of unpaired electrons to the nuclei. Therefore, the NMR sensitivity in these paramagnetically doped crystals might be increased by DNP. In this paper we demonstrate the possibility of efficient DNP transfer in polycrystalline samples of [Co(en)3Cl3]2·NaCl·6H2O (en = ethylenediamine, C2H8N2) doped with Cr(III) in varying concentrations between 0.1 and 3 mol %. We demonstrate that (1)H, (13)C, and (59)Co can be polarized by irradiation of Cr(III) with 140 GHz microwaves at a magnetic field of 5 T. We further explain our findings on the basis of electron paramagnetic resonance spectroscopy of the Cr(III) site and analysis of its temperature-dependent zero-field splitting, as well as the dependence of the DNP enhancement factor on the external magnetic field and microwave power. This first demonstration of DNP transfer from one paramagnetic metal ion to its diamagnetic host metal ion will pave the way for future applications of DNP in paramagnetically doped materials or metalloproteins.

Dynamic Nuclear Polarization of 1H, 13C, and 59Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

PubMed Central

2015-01-01

The study of inorganic crystalline materials by solid-state NMR spectroscopy is often complicated by the low sensitivity of heavy nuclei. However, these materials often contain or can be prepared with paramagnetic dopants without significantly affecting the structure of the crystalline host. Dynamic nuclear polarization (DNP) is generally capable of enhancing NMR signals by transferring the magnetization of unpaired electrons to the nuclei. Therefore, the NMR sensitivity in these paramagnetically doped crystals might be increased by DNP. In this paper we demonstrate the possibility of efficient DNP transfer in polycrystalline samples of [Co(en)3Cl3]2·NaCl·6H2O (en = ethylenediamine, C2H8N2) doped with Cr(III) in varying concentrations between 0.1 and 3 mol %. We demonstrate that 1H, 13C, and 59Co can be polarized by irradiation of Cr(III) with 140 GHz microwaves at a magnetic field of 5 T. We further explain our findings on the basis of electron paramagnetic resonance spectroscopy of the Cr(III) site and analysis of its temperature-dependent zero-field splitting, as well as the dependence of the DNP enhancement factor on the external magnetic field and microwave power. This first demonstration of DNP transfer from one paramagnetic metal ion to its diamagnetic host metal ion will pave the way for future applications of DNP in paramagnetically doped materials or metalloproteins. PMID:25069794

Estimation of laceration length by emergency department personnel.

PubMed

Bourne, Christina L; Jenkins, M Adams; Brewer, Kori L

2014-11-01

Documentation and billing for laceration repair involves a description of wound length. We designed this study to test the hypothesis that emergency department (ED) personnel can accurately estimate wound lengths without the aid of a measuring device. This was a single-center prospective observational study performed in an academic ED. Seven wounds of varying lengths were simulated by creating lacerations on purchased pigs' ears and feet. We asked healthcare providers, defined as nurses and physicians working in the ED, to estimate the length of each wound by visual inspection. Length estimates were given in centimeters (cm) and inches. Estimated lengths were considered correct if the estimate was within 0.5 cm or 0.2 inches of the actual length. We calculated the differences between estimated and actual laceration lengths for each laceration and compared the accuracy of physicians to nurses using an unpaired t-test. Thirty-two physicians (nine faculty and 23 residents) and 16 nurses participated. All subjects tended to overestimate in cm and inches. Physicians were able to estimate laceration length within 0.5 cm 36% of the time and within 0.2 inches 29% of the time. Physicians were more accurate at estimating wound lengths than nurses in both cm and inches. Both physicians and nurses were more accurate at estimating shorter lengths (<5.0 cm) than longer (>5.0 cm). ED personnel are often unable to accurately estimate wound length in either cm or inches and tend to overestimate laceration lengths when based solely on visual inspection.

[Resident physicians' opinions of their emergency medicine training in Catalan hospitals].

PubMed

Coll-Vinent, Blanca; Carreño, Ana; Morales, Xavier; Cerón, Ariana; Gutiérrez, Edith Cristina; Surís, Xavier

2015-01-01

To know the opinion of medical residents in hospitals in Catalonia about the need for and usefulness of the training they receive in the emergency department. We sent an electronic questionnaire to all residents in Catalonia, through their cooperating supervisors. The questionnaire contained items to collect information on sociodemographic variables and attitudes toward emergency medicine. Items related to training covered the residents' assessment of the need for a rotation in the emergency department and the knowledge and skills acquired during the rotation (case history writing, relations with patients' relatives, teamwork, decision-making, identifying and managing critical patients, acquisition of diagnostic and therapeutic techniques). We compiled descriptive statistics and compared the results for residents from different specialties. Questionnaires were sent to 1431 residents in 21 hospitals and other training facilities. Responses were received from 427 (29.8%). Mean (SD) scores expressed on a scale of 1 to 10 were high for both the need for training in emergency medicine (8.9 [1.7]) and knowledge acquired during the rotation (8.2 [1.9]). The residents reported that they had acquired more knowledge in the areas of decision-making and management of critical patients. Family medicine residents expressed greater interest in choosing the specialty of emergency medicine (33.7% vs 6.1% for other residents, P<.001), and their opinion of the need for training in emergency medicine was also higher than other residents' (9.2 [1.5] vs 8.7 [1.8], P=.006). Medical residents in Catalonia believe that a rotation in the emergency department provides necessary and useful training. Family medicine residents are the ones who value emergency training most highly.

Survey of Individual and Institutional Risk Associated with the Use of Social Media.

PubMed

Garg, Manish; Pearson, David A; Bond, Michael C; Runyon, Michael; Pillow, M Tyson; Hopson, Laura; Cooney, Robert R; Khadpe, Jay; Nomura, Jason T; Inboriboon, Pholaphat C

2016-05-01

Residents and faculty in emergency medicine (EM) residency programs might be unaware of the professional and legal risks associated with the use of social media (SM). The objective of this study was to identify and characterize the types and reported incidence of unprofessional SM behavior by EM residents, faculty, and nurses and the concomitant personal and institutional risks. This multi-site study used an 18-question survey tool that was distributed electronically to the leaders of multiple EM residency programs, members of the Council of Emergency Medicine Residency Directors (CORD), and the residents of 14 EM programs during the study period May to June 2013. We received 1,314 responses: 772 from residents and 542 from faculty. Both groups reported encountering high-risk-to-professionalism events (HRTPE) related to SM use by residents and non-resident providers (NRPs), i.e., faculty members and nurses. Residents reported posting of one of the following by a resident peer or nursing colleague: identifiable patient information (26%); or a radiograph, clinical picture or other image (52%). Residents reported posting of images of intoxicated colleagues (84%), inappropriate photographs (66%), and inappropriate posts (73%). Program directors (PDs) reported posting one of the following by NRPs and residents respectively: identifiable patient information (46% and 45%); a radiograph, clinical picture or other image (63% and 58%). PDs reported that NRPs and residents posted images of intoxicated colleagues (64% and 57%), inappropriate photographs (63% and 57%), or inappropriate posts (76% and 67%). The directors also reported that they were aware of or issued reprimands or terminations at least once a year (30% NRPs and 22% residents). Residents were more likely to post photos of their resident peers or nursing colleagues in an intoxicated state than were NRPs (p=0.0004). NRPs were more likely to post inappropriate content (p=0.04) and identifiable patient information (p=0.0004) than were residents. EM residents and faculty members cause and encounter HRTPE frequently while using SM; these events present significant risks to the individuals responsible and their associated institution. Awareness of these risks should prompt responsible SM use and consideration of CORD's Social Media Task Force recommendations.

Impact of adding additional providers to resident workload and the resident experience on a medical consultation rotation.

PubMed

Fang, Michele; Linson, Eric; Suneja, Manish; Kuperman, Ethan F

2017-02-22

Excellence in Graduate Medical Education requires the right clinical environment with an appropriate workload where residents have enough patients to gain proficiency in medicine with optimal time for reflection. The Accreditation Council for Graduate Medical Education (ACGME) has focused more on work hours rather than workload; however, high resident workload has been associated with lower resident participation in education and fatigue-related errors. Recognizing the potential risks associated with high resident workload and being mindful of the costs of reducing resident workload, we sought to reduce residents' workload by adding an advanced practice provider (APP) to the surgical comanagement service (SCM) and study its effect on resident satisfaction and perceived educational value of the rotation. In Fiscal Year (FY) 2014 and 2015, an additional faculty member was added to the SCM rotation. In FY 2014, the faculty member was a staff physician, and in FY 2015, the faculty member was an APP.. Resident workload was assessed using billing data. We measured residents' perceptions of the rotation using an anonymous electronic survey tool. We compared FY2014-2015 data to the baseline FY2013. The number of patients seen per resident per day decreased from 8.0(SD 3.3) in FY2013 to 5.0(SD 1.9) in FY2014 (p < 0.001) and 5.7(SD 2.0) in FY2015 (p < 0.001). A higher proportion of residents reported "just right" patient volume (64.4%, 91.7%, 96.7% in FY2013, 2014, 2015 respectively p < 0.001), meeting curricular goals (79.9%, 95.0%, 97.2%, in FY2013, 2014 and 2015 respectively p < 0.001), and overall educational value of the rotation (40.0%, 72.2%, 72.6% in FY2013, 2014, 2015 respectively, p < 0.001). Decreasing resident workload through adding clinical faculty (both staff physician and APPs) was associated with improvements on resident perceived educational value and clinical experience of a medical consultation rotation.

An Exploration of Structures in the Transitional Odd-Odd Nucleus Lu-160

DTIC Science & Technology

2015-05-18

25 3.4.1 CSM Quantum Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.2 Coriolis Effects ...22 14 Quasiparticle energy levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 15 Coriolis effect in time-reversed orbits...for various unpaired particles [21]. This notation is summarized in Table 1. 3.4.2 Coriolis Effects The Coriolis effect or the Coriolis force is most

40 CFR 86.1306-07 - Equipment required and specifications; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... alternate and reference averages; these are Asd and Rsd respectively. Asd must be less than or equal to Rsd. If Asd is greater than Rsd, the Administrator will not approve the application. (D) For an unpaired comparison, calculate the t-value: tunpaired = (Aavg−Ravg)/((Asd 2+Rsd 2)/n)1/2 (E) For a paired comparison...

40 CFR 86.1306-07 - Equipment required and specifications; overview.

Code of Federal Regulations, 2013 CFR

2013-07-01

... alternate and reference averages; these are Asd and Rsd respectively. Asd must be less than or equal to Rsd. If Asd is greater than Rsd, the Administrator will not approve the application. (D) For an unpaired comparison, calculate the t-value: tunpaired = (Aavg−Ravg)/((Asd 2+Rsd 2)/n)1/2 (E) For a paired comparison...

40 CFR 86.1306-07 - Equipment required and specifications; overview.

Code of Federal Regulations, 2012 CFR

2012-07-01

... alternate and reference averages; these are Asd and Rsd respectively. Asd must be less than or equal to Rsd. If Asd is greater than Rsd, the Administrator will not approve the application. (D) For an unpaired comparison, calculate the t-value: tunpaired = (Aavg−Ravg)/((Asd 2+Rsd 2)/n)1/2 (E) For a paired comparison...

40 CFR 86.1306-07 - Equipment required and specifications; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... alternate and reference averages; these are Asd and Rsd respectively. Asd must be less than or equal to Rsd. If Asd is greater than Rsd, the Administrator will not approve the application. (D) For an unpaired comparison, calculate the t-value: tunpaired = (Aavg−Ravg)/((Asd 2+Rsd 2)/n)1/2 (E) For a paired comparison...

The responsible use of online social networking: who should mentor medical students.

PubMed

Patel, Pradip D; Roberts, John L; Miller, Karen Hughes; Ziegler, Craig; Ostapchuk, Michael

2012-01-01

As medical students become more active in online social networking (OSN), there are increasing concerns regarding violations of patient privacy and a lack of professionalism. Students need to be mentored, but who is best suited to the task? We hypothesized that residents are closer to students in usage and attitudes toward online communication than are faculty. If so, they would be more credible as mentors. We surveyed faculty (N = 16), 1st-year residents (N = 120), and 3rd-year medical students (N = 130) to compare attitudes about OSN and the online usage patterns. We found residents to be more like students in usage patterns of personal electronic media and in their choice of the mentoring techniques that should be used. Residents say they were not prepared to mentor students without additional guidance but were more confident than faculty members that they had the knowledge to do so.

An assessment of patient sign-outs conducted by University at Buffalo internal medicine residents.

PubMed

Wheat, Deirdre; Co, Christopher; Manochakian, Rami; Rich, Ellen

2012-01-01

Internal medicine residents were surveyed regarding patient sign-outs at shift change. Data were used to design and implement interventions aimed at improving sign-out quality. This quasi-experimental project incorporated the Plan, Do, Study, Act methodology. Residents completed an anonymous electronic survey regarding experiences during sign-outs. Survey questions assessed structure, process, and outcome of sign-outs. Analysis of qualitative and quantitative data was performed; interventions were implemented based on survey findings. A total of 120 surveys (89% response) and 115 surveys (83% response) were completed by residents of 4 postgraduate years in response to the first (2008) and second (2009) survey requests, respectively. Approximately 79% of the respondents to the second survey indicated that postintervention sign-out systems were superior to preintervention systems. Results indicated improvement in specific areas of structure, process, and outcome. Survey-based modifications to existing sign-out systems effected measurable quality improvement in structure, process, and outcome.

Perceptions of Pediatric Residents Regarding Counseling About Use of Social Networking Sites.

PubMed

Banker, Sumeet L; Fenick, Ada M; Qin, Li; Talwalkar, Jaideep S

2018-04-01

Increasing use of social networking sites (SNS) among youth prompted professional organizations to urge pediatricians to promote healthy media use. Electronic questionnaires were distributed to 76 pediatric residents at one academic center measuring attitudes, practices, and familiarity with SNS. Of 43 respondents (response rate = 57%), most reported personal SNS use (98%) and familiarity with SNS used by youth (72%), and 88% agreed that pediatricians should provide counseling on SNS use. Only 5% felt they had adequate training on SNS use in children, and just 26% felt comfortable advising families. Residents were less likely to discuss SNS use than general media use (19% vs 56%, P = .007). Media counseling was correlated with SNS counseling ( r = .38, P = .01). Pediatric residents recognize the importance of guiding families on SNS use, yet do not routinely provide counseling despite high levels of personal SNS use and familiarity. Focused training is necessary for pediatricians to prioritize practical guidance.

National survey of mentorship in Canadian general surgery residency programs: Where are we and what do we need?

PubMed Central

Delisle, Megan; Rivard, Justin; Hebbard, Pamela; McCarthy, Brendan; Wirtzfeld, Debrah

2017-01-01

Background The benefits of mentorship on residents are well established. The current state of mentorship in General Surgery (GS) residency programs in Canada is unknown. The objectives of this study were to obtain GS residents’ and program directors’ (PD) perspectives on resident mentorship. Study Design An electronic survey was developed and distributed to all 601 GS residents in Canada. All 17 PDs were invited for telephone interviews. Results A total of 179 of the 601 residents responded. Ninety-seven percent (n=173) felt mentorship was important. Only 67% (n=116) identified a mentor and only 53% (n=62) reported a mentorship program. Most who identified a mentor (n=87/110, 79%) were satisfied with the mentorship received. Significant variations in mentorship existed between demographic subgroups and mentorship program types. Overall, residents (n=121, 74%) favoured having a required mentorship program. A total of 11 out of 17 PDs participated in the telephone interviews. The majority of PDs (n=9, 82%) were satisfied with current resident mentorship but most acknowledged that barriers exist (n=8, 73%). Conclusion GS programs in Canada should ensure they are providing equal opportunities for mentorship across demographic subgroups. Programs are encouraged to examine both their program’s and their residents’ needs as well as local barriers to improve mentorship. PMID:29354196

Problem neurology residents: a national survey.

PubMed

Tabby, David S; Majeed, Muhammed H; Schwartzman, Robert J

2011-06-14

Problem residents are found across most medical specialties at a prevalence of about 10%. This study was designed to explore the prevalence and causes of problem neurology residents and to compare neurology programs' responses and outcomes. Directors of 126 US neurology residency programs were sent an electronic survey. We collected data on demographics, first and all "identifiers" of problem residents, and year of training in which the problem was found. We asked about observable signs, etiology, and who performed remediation. We asked what resources were used and what outcomes occurred. Ninety-five program directors completed surveys (75% response rate). Almost all neurology programs have problem residents (81%). Age, sex, marital status, being a US native, or attending a US medical school had no effect on problem status. Being a parent carried a lower likelihood of problems (32%). Most commonly the problem is acted on during the first year of training. Faculty members without defined educational roles were the most frequent first identifiers. Program directors were the most common remediators. The most common remediation techniques were increasing supervision and assigning a faculty mentor. Graduate medical education office and psychiatric or psychological counseling services were most often used. Eleven percent of problem residents required a program for impaired physicians and 14% required a leave of absence. Sixteen percent were dismissed from their programs. The prevalence of problem residents in neurology is similar to other disciplines, and various resources are available to remediate them.

Navigating the Next Accreditation System: A Dashboard for the Milestones.

PubMed

Johna, Samir; Woodward, Brandon

2015-01-01

In July 2014, all residency programs accredited by the Accreditation Council for Graduate Medical Education (ACGME) were enrolled in a new system called the Next Accreditation System. Residency programs may not be clear on how best to comply with these new accreditation requirements. Large amounts of data must be collected, evaluated, and submitted twice a year to the council's Web-based data collection system. One challenge is that the new "end-of-rotation" evaluations must reflect specialty-specific milestones, on which many faculty members are not well versed. Like other residency programs, we tried to address the challenges using our local resources. We used our existing electronic goals and objectives for each rotation coupled with appropriate end-of-rotation evaluations reflecting the specialty-specific milestones through a process of editing and mapping. Data extracted from these evaluations were added to an interactive dashboard that also contained evaluations on additional program-specific modifiers of residents' performance. A resident's final overall performance was visually represented on a plot graph. The novel dashboard included features to save evaluations for future comparisons and to track residents' progress during their entire training. It proved simple to use and was able to reduce the time needed for each resident evaluation to 5 to 10 minutes. This tool has made it much easier and less challenging for the members of our Clinical Competency Committee to start deliberation about each resident's performance.

Leveraging new information technology to monitor medicine use in 71 residential aged care facilities: variation in polypharmacy and antipsychotic use.

PubMed

Pont, Lisa G; Raban, Magda Z; Jorgensen, Mikaela L; Georgiou, Andrew; Westbrook, Johanna I

2018-06-08

The aim of this study was to use routinely collected electronic medicines administration (eMAR) data in residential aged care (RAC) to investigate the quality use of medicines. A cross-sectional analysis of eMAR data. 71 RAC facilities in New South Wales and the Australian Capital Territory, Australia. Permanent residents living in a participating facility on 1 October 2015. None. Variation in polypharmacy (≥5 medications), hyper-polypharmacy (≥10 medications) and antipsychotic use across facilities was examined using funnel plot analysis. The study dataset included 4775 long-term residents. The mean resident age was 85.3 years and 70.6% of residents were female. The median facility size was 60 residents and 74.3% were in metropolitan locations. 84.3% of residents had polypharmacy, 41.2% hyper-polypharmacy and 21.0% were using an antipsychotic. The extent of polypharmacy (69.75-100% of residents), hyper-polypharmacy (38.81-76.19%) and use of antipsychotic medicines (0-75.6%) varied considerably across the 71 facilities. Using eMAR data we found substantial variation in polypharmacy, hyper-polypharmacy and antipsychotic medicine use across 71 RAC facilities. Further investigation into the policies and practices of facilities performing above or below expected levels is warranted to understand variation and drive quality improvement.

Utilization of personal digital assistants (PDAS) by pediatric and emergency medicine residents.

PubMed

Khan, Abu N G A; Frank, Joshua; Geria, Rajesh; Davidson, Steven

2007-05-01

The objective of the present study was to investigate the current personal digital assistant (PDA) usage patterns of the residents and their interest in future PDA-based applications. A cross-sectional survey was conducted among the Pediatrics (Peds) and Emergency Medicine (EM) residents in an urban teaching hospital. Data points included level of training, specialty of training, experience of use of different PDA devices, use of current software applications, and interest in future applications. A total of 60/74 (81%) eligible residents participated in the study. Palm (Palm Inc., Sunnyvale, CA) was the most commonly used operating system (82%). Among the PDA users, 82% reported using the device several times a day, and 16% used them a few times a week. The most commonly used applications included the simple calculator (81%), drug references (80%), medical calculators (75%), electronic textbooks (66%), and schedule and contact information (42%). In addition, residents showed interest in using PDA applications for procedure logs, patient tracking, and prescription writing. No significant differences were noted in the frequency and expertise of using PDAs between the Peds and EM residents (p = 0.29). Our data show current trends of use of PDAs by Peds and EM residents and their interest for future applications.

Residency Training in Robotic General Surgery: A Survey of Program Directors

PubMed Central

George, Lea C.; O'Neill, Rebecca

2018-01-01

Objective Robotic surgery continues to expand in minimally invasive surgery; however, the literature is insufficient to understand the current training process for general surgery residents. Therefore, the objectives of this study were to identify the current approach to and perspectives on robotic surgery training. Methods An electronic survey was distributed to general surgery program directors identified by the Accreditation Council for Graduate Medical Education website. Multiple choice and open-ended questions regarding current practices and opinions on robotic surgery training in general surgery residency programs were used. Results 20 program directors were surveyed, a majority being from medium-sized programs (4–7 graduating residents per year). Most respondents (73.68%) had a formal robotic surgery curriculum at their institution, with 63.16% incorporating simulation training. Approximately half of the respondents believe that more time should be dedicated to robotic surgery training (52.63%), with simulation training prior to console use (84.21%). About two-thirds of the respondents (63.16%) believe that a formal robotic surgery curriculum should be established as a part of general surgery residency, with more than half believing that exposure should occur in postgraduate year one (55%). Conclusion A formal robotics curriculum with simulation training and early surgical exposure for general surgery residents should be given consideration in surgical residency training. PMID:29854454

Residency Training in Robotic General Surgery: A Survey of Program Directors.

PubMed

George, Lea C; O'Neill, Rebecca; Merchant, Aziz M

2018-01-01

Robotic surgery continues to expand in minimally invasive surgery; however, the literature is insufficient to understand the current training process for general surgery residents. Therefore, the objectives of this study were to identify the current approach to and perspectives on robotic surgery training. An electronic survey was distributed to general surgery program directors identified by the Accreditation Council for Graduate Medical Education website. Multiple choice and open-ended questions regarding current practices and opinions on robotic surgery training in general surgery residency programs were used. 20 program directors were surveyed, a majority being from medium-sized programs (4-7 graduating residents per year). Most respondents (73.68%) had a formal robotic surgery curriculum at their institution, with 63.16% incorporating simulation training. Approximately half of the respondents believe that more time should be dedicated to robotic surgery training (52.63%), with simulation training prior to console use (84.21%). About two-thirds of the respondents (63.16%) believe that a formal robotic surgery curriculum should be established as a part of general surgery residency, with more than half believing that exposure should occur in postgraduate year one (55%). A formal robotics curriculum with simulation training and early surgical exposure for general surgery residents should be given consideration in surgical residency training.