Multicomponent Electron-Hole Superfluidity and the BCS-BEC Crossover in Double Bilayer Graphene

NASA Astrophysics Data System (ADS)

Conti, S.; Perali, A.; Peeters, F. M.; Neilson, D.

2017-12-01

Superfluidity in coupled electron-hole sheets of bilayer graphene is predicted here to be multicomponent because of the conduction and valence bands. We investigate the superfluid crossover properties as functions of the tunable carrier densities and the tunable energy band gap Eg. For small band gaps there is a significant boost in the two superfluid gaps, but the interaction-driven excitations from the valence to the conduction band can weaken the superfluidity, even blocking the system from entering the Bose-Einstein condensate (BEC) regime at low densities. At a given larger density, a band gap Eg˜80 - 120 meV can carry the system into the strong-pairing multiband BCS-BEC crossover regime, the optimal range for realization of high-Tc superfluidity.

Through-plane conductivities of membranes for nonaqueous redox flow batteries

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

Anderson, Travis Mark; Small, Leo J.; Pratt, III, Harry D.

In this study, nonaqueous redox flow batteries (RFB) leverage nonaqueous solvents to enable higher operating voltages compared to their aqueous counterparts. Most commercial components for flow batteries, however, are designed for aqueous use. One critical component, the ion-selective membrane, provides ionic conductance between electrodes while preventing crossover of electroactive species. Here we evaluate the area-specific conductances and through-plane conductivities of commercially available microporous separators (Celgard 2400, 2500) and anion exchange membranes (Neosepta AFX, Neosepta AHA, Fumasep FAP-450, Fumasep FAP-PK) soaked in acetonitrile, propylene carbonate, or two imidazolium-based ionic liquids. Fumasep membranes combined with acetonitrile-based electrolyte solutions provided the highest conductancemore » values and conductivities by far. When tested in ionic liquids, all anion exchange membranes displayed conductivities greater than those of the Celgard microporous separators, though the separators’ decreased thickness-enabled conductances on par with the most conductive anion exchange membranes. Ionic conductivity is not the only consideration when choosing an anion exchange membrane; testing of FAP-450 and FAP-PK membranes in a nonaqueous RFB demonstrated that the increased mechanical stability of PEEK-supported FAP-PK minimized swelling, in turn decreasing solvent mediated crossover and enabling greater electrochemical yields (40% vs. 4%) and Coulombic efficiencies (94% vs. 90%) compared to the unsupported, higher conductance FAP-450.« less

Through-plane conductivities of membranes for nonaqueous redox flow batteries

DOE PAGES

Anderson, Travis Mark; Small, Leo J.; Pratt, III, Harry D.; ...

2015-08-13

In this study, nonaqueous redox flow batteries (RFB) leverage nonaqueous solvents to enable higher operating voltages compared to their aqueous counterparts. Most commercial components for flow batteries, however, are designed for aqueous use. One critical component, the ion-selective membrane, provides ionic conductance between electrodes while preventing crossover of electroactive species. Here we evaluate the area-specific conductances and through-plane conductivities of commercially available microporous separators (Celgard 2400, 2500) and anion exchange membranes (Neosepta AFX, Neosepta AHA, Fumasep FAP-450, Fumasep FAP-PK) soaked in acetonitrile, propylene carbonate, or two imidazolium-based ionic liquids. Fumasep membranes combined with acetonitrile-based electrolyte solutions provided the highest conductancemore » values and conductivities by far. When tested in ionic liquids, all anion exchange membranes displayed conductivities greater than those of the Celgard microporous separators, though the separators’ decreased thickness-enabled conductances on par with the most conductive anion exchange membranes. Ionic conductivity is not the only consideration when choosing an anion exchange membrane; testing of FAP-450 and FAP-PK membranes in a nonaqueous RFB demonstrated that the increased mechanical stability of PEEK-supported FAP-PK minimized swelling, in turn decreasing solvent mediated crossover and enabling greater electrochemical yields (40% vs. 4%) and Coulombic efficiencies (94% vs. 90%) compared to the unsupported, higher conductance FAP-450.« less

Crossover of exhaustion between dentists and dental nurses.

PubMed

Hakanen, Jari J; Perhoniemi, Riku; Bakker, Arnold B

2014-04-01

The aim of this study was to investigate the conditions under which job-related exhaustion may transmit (cross over) from dentists to dental nurses and vice versa. We conducted a cross-sectional survey study among 470 Finnish dentist-dental nurse dyads and used moderated structural equation modelling analyses. We found no support for the direct crossover of exhaustion from one work partner to the other. Instead, we found that exhaustion transferred from dentists to dental nurses only when collaboration was frequent and dental nurses perceived the collaboration as friendly or consisting of mutual feedback. In contrast, dentists were not affected by dental nurses' exhaustion. These results indicate that exhaustion can be contagious in work dyads and may be fuelled by positive and frequent interpersonal relationships when the partner who is higher in the hierarchy has high (versus low) levels of exhaustion. Thus, interpersonal and hierarchical relationships among work partners may play an important role in the crossover process. Limitations and implications are mentioned. © 2013 John Wiley & Sons, Ltd.

Recent advances on Zeolite modification for direct alcohol fuel cells (DAFCs)

NASA Astrophysics Data System (ADS)

Makertihartha, I. G. B. N.; Zunita, M.; Rizki, Z.; Dharmawijaya, P. T.

2017-03-01

The increase of energy demand and global warming issues has driven studies of alternative energy sources. The polymer electrolyte membrane fuel cell (PEMFC) can be an alternative energy source by (partially) replacing the use of fossil fuel which is in line with the green technology concept. However, the usage of hydrogen as a fuel has several disadvantages mainly transportation and storage related to its safety aspects. Recently, alcohol has gained attention as an energy source for fuel cell application, namely direct alcohol fuel cell (DAFC). Among alcohols, high-mass energy density methanol and ethanol are widely used as direct methanol fuel cell (DMFC) and direct ethanol fuel cell (DEFC), respectively. Currently, the performance of DMFC is still rudimentary. Furthermore, the use of ethanol gives some additional privileges such as non-toxic property, renewable, ease of production in great quantity by the fermentation of sugar-containing raw materials. Direct alcohol fuel cell (DAFC) still has weakness in the low proton conductivity and high alcohol crossover. Therefore, to increase the performance of DAFC, modification using zeolite has been performed to improve proton conductivity and decrease alcohol crossover. Zeolite also has high thermal resistance properties, thereby increasing DAFC performance. This paper will discuss briefly about modification of catalyst and membrane for DAFC using zeolite. Zeolite modification effect on fuel cell performance especially proton conductivity and alcohol crossover will be presented in detail.

Impact of membrane characteristics on the performance and cycling of the Br-2-H-2 redox flow cell

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

Tucker, MC; Cho, KT; Spingler, FB

2015-06-15

The Br-2/H-2 redox flow cell shows promise as a high-power, low-cost energy storage device. In this paper, the effect of various aspects of material selection and processing of proton exchange membranes on the operation of the Br-2/H-2 redox flow cell is determined. Membrane properties have a significant impact on the performance and efficiency of the system. In particular, there is a tradeoff between conductivity and crossover, where conductivity limits system efficiency at high current density and crossover limits efficiency at low current density. The impact of thickness, pretreatment procedure, swelling state during cell assembly, equivalent weight, membrane reinforcement, and additionmore » of a microporous separator layer on this tradeoff is assessed. NR212 (50 mu m) pretreated by soaking in 70 degrees C water is found to be optimal for the studied operating conditions. For this case, an energy efficiency of greater than 75% is achieved for current density up to 400 mA cm(-2), with a maximum obtainable energy efficiency of 88%. A cell with this membrane was cycled continuously for 3164 h. Membrane transport properties, including conductivity and bromine and water crossover, were found to decrease moderately upon cycling but remained higher than those for the as-received membrane. (C) 2015 Elsevier B.V. All rights reserved.« less

Organic-aqueous crossover coating process for the desmopressin orally disintegrating microparticles.

PubMed

Kim, Ju-Young; Hwang, Kyu-Mok; Park, Chun-Woong; Rhee, Yun-Seok; Park, Eun-Seok

2015-02-01

The purpose of the present study was to prepare desmopressin orally disintegrating microparticles (ODMs) using organic-aqueous crossover coating process which featured an organic sub-coating followed by an aqueous active coating. Sucrose beads and hydroxypropyl cellulose (HPC) were used as inert cores and a coating material, respectively. Characterizations including size distribution analysis, in-vitro release studies and in-vitro disintegration studies were performed. A pharmacokinetic study of the ODMs was also conducted in eight beagle dogs. It was found that sucrose beads should be coated using organic solvents to preserve their original morphology. For the active coating, the aqueous coating solution should be used for drug stability. When sucrose beads were coated using organic-aqueous crossover coating process, double-layer ODMs with round shapes were produced with detectable impurities below limit of US Pharmacopeia. The median size of ODMs was 195.6 μm, which was considered small enough for a good mouthfeel. The ODMs dissolved in artificial saliva within 15 s because of hydrophilic materials including sucrose and HPC in the ODMs. Because of its fast-dissolving properties, 100% release of the drug was reached within 5 min. Pharmacokinetic parameters including Cmax and AUC24 indicated bioequivalence of the ODMs and the conventional immediate release tablets. Therefore, by using the organic-aqueous crossover coating process, double-layer ODMs were successively prepared with small size, round shapes and good drug stability.

Deanol, lithium and placebo in the treatment of tardive dyskinesia. A double-blind crossover study.

PubMed

Jus, A; Villeneuve, A; Gautier, J; Jus, K; Villeneuve, C; Pires, P; Villeneuve, R

1978-01-01

A double-blind crossover study on the effects of deanol and lithium carbonate was conducted on a sample of 29 chronic schizophrenic patients with tardive dyskinesia. In addition to his usual treatment with different neuroleptics, each patient received during an 8-week period either deanol, lithium carbonate or placebo. A 4-week wash-out period was inserted between each of the 8-week periods of experimental treatment of the tardive dyskinesia. The administration of either deanol, lithium carbonate or placebo added to the neuroleptic treatment did not produce a statistically significant improvement of tardive dyskinesia in our patient population as a whole. Favorable and unfavorable responses are discussed.

From tunneling to contact: Inelastic signals in an atomic gold junction from first principles

NASA Astrophysics Data System (ADS)

Frederiksen, Thomas; Lorente, Nicolás; Paulsson, Magnus; Brandbyge, Mads

2007-06-01

The evolution of electron conductance in the presence of inelastic effects is studied as an atomic gold contact is formed evolving from a low-conductance regime (tunneling) to a high-conductance regime (contact). In order to characterize each regime, we perform density-functional theory (DFT) calculations to study the geometric and electronic structures, together with the strength of the atomic bonds and the associated vibrational frequencies. The conductance is calculated by, first, evaluating the transmission of electrons through the system and, second, by calculating the conductance change due to the excitation of vibrations. As found in previous studies [Paulsson , Phys. Rev. B 72, 201101(R) (2005)], the change in conductance due to inelastic effects permits us to characterize the crossover from tunneling to contact. The most notorious effect is the crossover from an increase in conductance in the tunneling regime to a decrease in conductance in the contact regime when the bias voltage matches a vibrational threshold. Our DFT-based calculations actually show that the effect of vibrational modes in electron conductance is rather complex, in particular, when modes localized in the contact region are permitted to extend into the electrodes. As an example, we find that certain modes can give rise to decreases in conductance when in the tunneling regime, opposite to the above-mentioned result. Whereas details in the inelastic spectrum depend on the size of the vibrational region, we show that the overall change in conductance is quantitatively well approximated by the simplest calculation where only the apex atoms are allowed to vibrate. Our study is completed by the application of a simplified model where the relevant parameters are obtained from the above DFT-based calculations.

Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices.

PubMed

Ravichandran, Jayakanth; Yadav, Ajay K; Cheaito, Ramez; Rossen, Pim B; Soukiassian, Arsen; Suresha, S J; Duda, John C; Foley, Brian M; Lee, Che-Hui; Zhu, Ye; Lichtenberger, Arthur W; Moore, Joel E; Muller, David A; Schlom, Darrell G; Hopkins, Patrick E; Majumdar, Arun; Ramesh, Ramamoorthy; Zurbuchen, Mark A

2014-02-01

Elementary particles such as electrons or photons are frequent subjects of wave-nature-driven investigations, unlike collective excitations such as phonons. The demonstration of wave-particle crossover, in terms of macroscopic properties, is crucial to the understanding and application of the wave behaviour of matter. We present an unambiguous demonstration of the theoretically predicted crossover from diffuse (particle-like) to specular (wave-like) phonon scattering in epitaxial oxide superlattices, manifested by a minimum in lattice thermal conductivity as a function of interface density. We do so by synthesizing superlattices of electrically insulating perovskite oxides and systematically varying the interface density, with unit-cell precision, using two different epitaxial-growth techniques. These observations open up opportunities for studies on the wave nature of phonons, particularly phonon interference effects, using oxide superlattices as model systems, with extensive applications in thermoelectrics and thermal management.

Oolong tea does not improve glucose metabolism in non-diabetic adults

USDA-ARS?s Scientific Manuscript database

Studies of the influence of tea on glucose metabolism have produced inconsistent results, possibly due to lack of dietary control and/or unclear characterization of tea products. Therefore, a double-blind crossover study was conducted in which healthy males (n=19) consumed each of three oolong tea ...

A Crossover Trial Evaluating an Educational-Behavioral Joint Protection Programme for People with Rheumatoid Arthritis.

ERIC Educational Resources Information Center

Hammond, A.; Lincoln, N.; Sutcliffe, L.

1999-01-01

Joint protection, a self-management technique taught to people with rheumatoid arthritis, was used in a group education program. A crossover trial (N=35) was conducted. No significant changes in measures of pain, functional disability, grip strength, self-efficacy or helplessness occurred post-education, although this may have been due to the…

Investigation of Sustained Detonation Devices: the Pulse Detonation Engine-Crossover System and the Rotating Detonation Engine System

NASA Astrophysics Data System (ADS)

Driscoll, Robert B.

An experimental study is conducted on a Pulse Detonation Engine-Crossover System to investigate the feasibility of repeated, shock-initiated combustion and characterize the initiation performance. A PDE-crossover system can decrease deflagration-to-detonation transition length while employing a single spark source to initiate a multi-PDE system. Visualization of a transferred shock wave propagating through a clear channel reveals a complex shock train behind the leading shock. Shock wave Mach number and decay rate remains constant for varying crossover tube geometries and operational frequencies. A temperature gradient forms within the crossover tube due to forward flow of high temperature ionized gas into the crossover tube from the driver PDE and backward flow of ionized gas into the crossover tube from the driven PDE, which can cause intermittent auto-ignition of the driver PDE. Initiation performance in the driven PDE is strongly dependent on initial driven PDE skin temperature in the shock wave reflection region. An array of detonation tubes connected with crossover tubes is developed using optimized parameters and successful operation utilizing shock-initiated combustion through shock wave reflection is achieved and sustained. Finally, an air-breathing, PDE-Crossover System is developed to characterize the feasibility of shock-initiated combustion within an air-breathing pulse detonation engine. The initiation effectiveness of shock-initiated combustion is compared to spark discharge and detonation injection through a pre-detonator. In all cases, shock-initiated combustion produces improved initiation performance over spark discharge and comparable detonation transition run-up lengths relative to pre-detonator initiation. A computational study characterizes the mixing processes and injection flow field within a rotating detonation engine. Injection parameters including reactant flow rate, reactant injection area, placement of the fuel injection, and fuel injection distribution are varied to assess the impact on mixing. Decreasing reactant injection areas improves fuel penetration into the cross-flowing air stream, enhances turbulent diffusion of the fuel within the annulus, and increases local equivalence ratio and fluid mixedness. Staggering fuel injection holes produces a decrease in mixing when compared to collinear fuel injection. Finally, emulating nozzle integration by increasing annulus back-pressure increases local equivalence ratio in the injection region due to increased convection residence time.

Thermopower of molecular junctions: Tunneling to hopping crossover in DNA

NASA Astrophysics Data System (ADS)

Korol, Roman; Kilgour, Michael; Segal, Dvira

2016-12-01

We study the electrical conductance G and the thermopower S of single-molecule junctions and reveal signatures of different transport mechanisms: off-resonant tunneling, on-resonant coherent (ballistic) motion, and multi-step hopping. These mechanisms are identified by studying the behavior of G and S while varying molecular length and temperature. Based on a simple one-dimensional model for molecular junctions, we derive approximate expressions for the thermopower in these different regimes. Analytical results are compared to numerical simulations, performed using a variant of Büttiker's probe technique, the so-called voltage-temperature probe, which allows us to phenomenologically introduce environmentally induced elastic and inelastic electron scattering effects, while applying both voltage and temperature biases across the junction. We further simulate the thermopower of GC-rich DNA sequences with mediating A:T blocks and manifest the tunneling-to-hopping crossover in both the electrical conductance and the thermopower, in accord with measurements by Li et al. [Nat. Commun. 7, 11294 (2016)].

Effects of a Worksite Weight-Control Programme in Obese Male Workers: A Randomized Controlled Crossover Trial

ERIC Educational Resources Information Center

Iriyama, Yae; Murayama, Nobuko

2014-01-01

Objective: We conducted a randomized controlled crossover trial to evaluate the effects of a new worksite weight-control programme designed for men with or at risk of obesity using a combination of nutrition education and nutrition environmental interventions. Subjects and methods: Male workers with or at risk of obesity were recruited for this…

The assessment of health policy changes using the time-reversed crossover design.

PubMed Central

Sollecito, W A; Gillings, D B

1986-01-01

The time-reversed crossover design is a quasi-experimental design which can be applied to evaluate the impact of a change in health policy on a large population. This design makes use of separate sampling and analysis strategies to improve the validity of conclusions drawn from such an evaluation. The properties of the time-reversed crossover design are presented including the use of stratification on outcome in the sampling stage, which is intended to improve external validity. It is demonstrated that, although this feature of the design introduces internal validity threats due to regression toward the mean in extreme-outcome strata, these effects can be measured and eliminated from the test of significance of treatment effects. Methods for within- and across-stratum estimation and hypothesis-testing are presented which are similar to those which have been developed for the traditional two-period crossover design widely used in clinical trials. The procedures are illustrated using data derived from a study conducted by the United Mine Workers of America Health and Retirement Funds to measure the impact of cost-sharing on health care utilization among members of its health plan. PMID:3081465

Quantum-interference transport through surface layers of indium-doped ZnO nanowires

NASA Astrophysics Data System (ADS)

Chiu, Shao-Pin; Lu, Jia Grace; Lin, Juhn-Jong

2013-06-01

We have fabricated indium-doped ZnO (IZO) nanowires (NWs) and carried out four-probe electrical-transport measurements on two individual NWs with geometric diameters of ≈70 and ≈90 nm in a wide temperature T interval of 1-70 K. The NWs reveal overall charge conduction behavior characteristic of disordered metals. In addition to the T dependence of resistance R, we have measured the magnetoresistance (MR) in magnetic fields applied either perpendicular or parallel to the NW axis. Our R(T) and MR data in different T intervals are consistent with the theoretical predictions of the one- (1D), two- (2D) or three-dimensional (3D) weak-localization (WL) and the electron-electron interaction (EEI) effects. In particular, a few dimensionality crossovers in the two effects are observed. These crossover phenomena are consistent with the model of a ‘core-shell-like structure’ in individual IZO NWs, where an outer shell of thickness t (≃15-17 nm) is responsible for the quantum-interference transport. In the WL effect, as the electron dephasing length Lφ gradually decreases with increasing T from the lowest measurement temperatures, a 1D-to-2D dimensionality crossover takes place around a characteristic temperature where Lφ approximately equals d, an effective NW diameter which is slightly smaller than the geometric diameter. As T further increases, a 2D-to-3D dimensionality crossover occurs around another characteristic temperature where Lφ approximately equals t (

Quantum-interference transport through surface layers of indium-doped ZnO nanowires.

PubMed

Chiu, Shao-Pin; Lu, Jia Grace; Lin, Juhn-Jong

2013-06-21

We have fabricated indium-doped ZnO (IZO) nanowires (NWs) and carried out four-probe electrical-transport measurements on two individual NWs with geometric diameters of ≈70 and ≈90 nm in a wide temperature T interval of 1-70 K. The NWs reveal overall charge conduction behavior characteristic of disordered metals. In addition to the T dependence of resistance R, we have measured the magnetoresistance (MR) in magnetic fields applied either perpendicular or parallel to the NW axis. Our R(T) and MR data in different T intervals are consistent with the theoretical predictions of the one- (1D), two- (2D) or three-dimensional (3D) weak-localization (WL) and the electron-electron interaction (EEI) effects. In particular, a few dimensionality crossovers in the two effects are observed. These crossover phenomena are consistent with the model of a 'core-shell-like structure' in individual IZO NWs, where an outer shell of thickness t (~15-17 nm) is responsible for the quantum-interference transport. In the WL effect, as the electron dephasing length Lφ gradually decreases with increasing T from the lowest measurement temperatures, a 1D-to-2D dimensionality crossover takes place around a characteristic temperature where Lφ approximately equals d, an effective NW diameter which is slightly smaller than the geometric diameter. As T further increases, a 2D-to-3D dimensionality crossover occurs around another characteristic temperature where Lφ approximately equals t (

Defined-size DNA triple crossover construct for molecular electronics: modification, positioning and conductance properties.

PubMed

Linko, Veikko; Leppiniemi, Jenni; Paasonen, Seppo-Tapio; Hytönen, Vesa P; Toppari, J Jussi

2011-07-08

We present a novel, defined-size, small and rigid DNA template, a so-called B-A-B complex, based on DNA triple crossover motifs (TX tiles), which can be utilized in molecular scale patterning for nanoelectronics, plasmonics and sensing applications. The feasibility of the designed construct is demonstrated by functionalizing the TX tiles with one biotin-triethylene glycol (TEG) and efficiently decorating them with streptavidin, and furthermore by positioning and anchoring single thiol-modified B-A-B complexes to certain locations on a chip via dielectrophoretic trapping. Finally, we characterize the conductance properties of the non-functionalized construct, first by measuring DC conductivity and second by utilizing AC impedance spectroscopy in order to describe the conductivity mechanism of a single B-A-B complex using a detailed equivalent circuit model. This analysis also reveals further information about the conductivity of DNA structures in general.

Conductance of graphene based normal-superconductor junction with double magnetic barriers

NASA Astrophysics Data System (ADS)

Abdollahipour, B.; Mohebalipour, A.; Maleki, M. A.

2018-05-01

We study conductance of a graphene based normal metal-superconductor junction with two magnetic barriers. The magnetic barriers are induced via two applied magnetic fields with the same magnitudes and opposite directions accompanied by an applied electrostatic potential. We solve Dirac-Bogoliubov-De-Gennes (DBdG) equation to calculate conductance of the junction. We find that applying the magnetic field leads to suppression of the Andreev reflection and conductance for all energies. On the other hand, we observe a crossover from oscillatory to tunneling behavior of the conductance as a function of the applied potential by increasing the magnetic field.

Associations between summertime ambient pollutants and respiratory morbidity in New York City: Comparison of results using ambient concentrations versus predicted exposures

EPA Science Inventory

Epidemiological analyses of air quality often estimate human exposure from ambient monitoring data, potentially leading to exposure misclassification and subsequent bias in estimated health risks. To investigate this, we conducted a case-crossover study of summertime ambient ozon...

Paternal alcoholism and offspring conduct disorder: evidence for the 'common genes' hypothesis.

PubMed

Haber, Jon R; Jacob, Theodore; Heath, Andrew C

2005-04-01

Not only are alcoholism and externalizing disorders frequently comorbid, they often co-occur in families across generations; for example, paternal alcoholism predicts offspring conduct disorder just as it does offspring alcoholism. To clarify this relationship, the current study examined the 'common genes' hypothesis utilizing a children-of-twins research design. Participants were male monozygotic (MZ) and dizygotic (DZ) twins from the Vietnam Era Twin Registry who were concordant or discordant for alcohol dependence together with their offspring and the mothers of those offspring. All participants were conducted through a structured psychiatric interview. Offspring risk of conduct disorder was examined as a function of alcoholism genetic risk (due to paternal and co-twin alcohol dependence) and alcoholism environmental risk (due to being reared by a father with an alcohol dependence diagnosis). After controlling for potentially confounding variables, the offspring of alcohol-dependent fathers were significantly more likely to exhibit conduct disorder diagnoses than were offspring of nonalcohol-dependent fathers, thus indicating diagnostic crossover in generational family transmission. Comparing offspring at high genetic and high environmental risk with offspring at high genetic and low environmental risk indicated that genetic factors were most likely responsible for the alcoholism-conduct disorder association. The observed diagnostic crossover (from paternal alcoholism to offspring conduct disorder) across generations in the context of both high and low environmental risk (while genetic risk remained high) supported the common genes hypothesis.

A six-month crossover chemoprevention clinical trial of tea in smokers and non-smokers: methodological issues in a feasibility study

PubMed Central

2012-01-01

Background Chemoprevention crossover trials of tea can be more efficient than parallel designs but the attrition and compliance rates with such trials are unknown. Methods Attrition (dropouts) and compliance with treatment were assessed in a 25-week randomized, placebo controlled, crossover, feasibility clinical trial of four tea treatments to investigate the effect of tea on oral cancer biomarkers. Each treatment lasted 4 weeks with 2 weeks of washout in between. Participants were 32 smokers and 33 non-smokers without any evidence of premalignant oral lesions. The interventions consisted of packets of green tea, black tea, caffeinated water, or placebo. Participants were assigned to each treatment for four weeks, and were instructed to drink five packets per day while on the treatment. Dropout from the trial and compliance (consumption of ≥ 85% of the prescribed treatment packets) are the main outcome measures reported. Results There was a high rate of dropout (51%) from the study, and the rates were significantly higher among smokers (64%) than non-smokers (36%). Among participants who completed the study the rate of compliance was 72%. The highest rates of dropouts occurred between the first and second treatment visits in both smokers (38% dropout) and non-smokers (18% dropout). Throughout the study smokers were more likely to dropout than non-smokers. Black tea treatment was associated with the highest rates of dropout among smokers (37%), but was associated with the lowest rate of dropout among non-smokers (4%). Conclusions In a study conducted to test the feasibility of a four-treatment crossover tea trial, a high rate of dropout among smokers and non-smokers was observed. Multi-arm crossover tea trials might pose a higher burden on participants and research is needed to improve adherence and treatment compliance in such trials. Trial registration number ISRCTN70410203 PMID:22800470

High pressure induced crossover between metal and insulator conductivity type in low dimensionality electron systems

NASA Astrophysics Data System (ADS)

Dizhur, E.; Voronovskii, A.; Kostyleva, I.; Kotel'nikov, I.; Zaitsev-Zotov, S.

2011-12-01

We report the results of our recent experimental studies concerned with electron systems of lower dimensionality the conductivity of which may be toggled between metallic and insulating regime appliing high pressure. The objects under present study include: a) tunneling through Shottky barrier into two-dimension (2D) electron system formed in the δ-doped layer in GaAs under hydrostatic pressure up to 3 GPa in a cylinder-piston cell; b) quasi-one-dimension (1D) `insulator' crystals NbS3 which obtain metallic conductivity type at pressures above 5.5 GPa in `toroid' anvils.

Cross-over studies underestimate energy compensation: The example of sucrose-versus sucralose-containing drinks.

PubMed

Gadah, Nouf S; Brunstrom, Jeffrey M; Rogers, Peter J

2016-12-01

The vast majority of preload-test-meal studies that have investigated the effects on energy intake of disguised nutrient or other food/drink ingredient manipulations have used a cross-over design. We argue that this design may underestimate the effect of the manipulation due to carry-over effects. To test this we conducted comparable cross-over (n = 69) and parallel-groups (n = 48) studies testing the effects of sucrose versus low-calorie sweetener (sucralose) in a drink preload on test-meal energy intake. The parallel-groups study included a baseline day in which only the test meal was consumed. Energy intake in that meal was used to control for individual differences in energy intake in the analysis of the effects of sucrose versus sucralose on energy intake on the test day. Consistent with our prediction, the effect of consuming sucrose on subsequent energy intake was greater when measured in the parallel-groups study than in the cross-over study (respectively 64% versus 36% compensation for the 162 kcal difference in energy content of the sucrose and sucralose drinks). We also included a water comparison group in the parallel-groups study (n = 24) and found that test-meal energy intake did not differ significantly between the water and sucralose conditions. Together, these results confirm that consumption of sucrose in a drink reduces subsequent energy intake, but by less than the energy content of the drink, whilst drink sweetness does not increase food energy intake. Crucially, though, the studies demonstrate that study design affects estimated energy compensation. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Comparison of the inhibitory effects of cilostazol, acetylsalicylic acid and ticlopidine on platelet functions ex vivo. Randomized, double-blind cross-over study.

PubMed

Ikeda, Y; Kikuchi, M; Murakami, H; Satoh, K; Murata, M; Watanabe, K; Ando, Y

1987-05-01

A randomized double-blind cross-over study was conducted to determine the inhibitory effects of acetylsalicylic acid (ASA), ticlopidine (TP) and cilostazol (OPC-13013; in the following briefly called CS), a new antithrombotic agent on platelet functions ex vivo. Nine patients with cerebral thrombosis were enrolled in this study. Patients were given each of the three drugs for one week in a complete cross-over design according to a randomization schedule, followed by a wash-out period with a placebo for one week. It was found that CS and TP significantly inhibited platelet aggregation induced by ADP. Collagen- and arachidonic acid-induced platelet aggregation was all inhibited by CS, TP and ASA. Duncan's multiple range test to compare the anti-platelet effects of the three drugs revealed that: CS greater than ASA and TP greater than ASA in inhibiting ADP-induced platelet aggregation and CS greater than TP and ASA greater than TP in inhibiting arachidonic acid-induced platelet aggregation. These results may suggest that CS is superior to ASA and TP in inhibiting platelet aggregation ex vivo.

Hopping conduction in zirconium oxynitrides thin film deposited by reactive magnetron sputtering

NASA Astrophysics Data System (ADS)

Guo, Jie; Zhan, Guanghui; Liu, Jingquan; Yang, Bin; Xu, Bin; Feng, Jie; Chen, Xiang; Yang, Chunsheng

2015-10-01

Zirconium oxynitrides thin film thermometers were demonstrated to be useful temperature sensors. However, the basic conduction mechanism of zirconium oxynitrides films has been a long-standing issue, which hinders the prediction and optimization of their ultimate performance. In this letter, zirconium oxynitrides films were grown on sapphire substrates by magnetron sputtering and their electric transport mechanism has been systemically investigated. It was found that in high temperatures region (>150 K) the electrical conductivity was dominated by thermal activation for all samples. In the low temperatures range, while Mott variable hopping conduction (VRH) was dominated the transport for films with relatively low resistance, a crossover from Mott VRH conduction to Efros-Shklovskii (ES) VRH was observed for films with relatively high resistance. This low temperature crossover from Mott to ES VRH indicates the presence of a Coulomb gap (~7 meV). These results demonstrate the competing and tunable conduction mechanism in zirconium oxynitrides thin films, which would be helpful for optimizing the performance of zirconium oxynitrides thermometer.

Proton conductivity and methanol permeability of Nafion-SiO2/SiWA composite membranes

NASA Astrophysics Data System (ADS)

Thiam, Hui San; Chia, Min Yan; Cheah, Qiao Rou; Koo, Charlene Chai Hoon; Lai, Soon Onn; Chong, Kok Chung

2017-04-01

Proton exchange membranes for a direct methanol fuel cell (DMFC) were prepared by incorporating silica/silicotungstic acid (SiO2/SiWA) inorganic composite into a Nafion polymer. The effects of SiO2/SiWA content on proton conductivity of membranes were investigated by using a four-probe conductivity cell. Methanol permeability of composite membrane was also determined by using a homemade diffusion cell and gas chromatography technique. It was found that proton conductivity of the composite membranes decreased with SiO2/SiWA content, however the highest proton conductivity achieved was 11% greater than the pure recast Nafion membrane. The methanol permeability of composite membrane was much lower than that of pure recast Nafion, in a reduction of 58% which indicated a better resistance to fuel crossover. Nafion-SiO2/SiWA composite membrane showed promising advantages over pure Nafion on electrochemical properties such as proton conductivity and fuel crossover and it is potentially attractive for use in DMFC.

Testing for carryover effects after cessation of treatments: a design approach.

PubMed

Sturdevant, S Gwynn; Lumley, Thomas

2016-08-02

Recently, trials addressing noisy measurements with diagnosis occurring by exceeding thresholds (such as diabetes and hypertension) have been published which attempt to measure carryover - the impact that treatment has on an outcome after cessation. The design of these trials has been criticised and simulations have been conducted which suggest that the parallel-designs used are not adequate to test this hypothesis; two solutions are that either a differing parallel-design or a cross-over design could allow for diagnosis of carryover. We undertook a systematic simulation study to determine the ability of a cross-over or a parallel-group trial design to detect carryover effects on incident hypertension in a population with prehypertension. We simulated blood pressure and focused on varying criteria to diagnose systolic hypertension. Using the difference in cumulative incidence hypertension to analyse parallel-group or cross-over trials resulted in none of the designs having acceptable Type I error rate. Under the null hypothesis of no carryover the difference is well above the nominal 5 % error rate. When a treatment is effective during the intervention period, reliable testing for a carryover effect is difficult. Neither parallel-group nor cross-over designs using the difference in cumulative incidence appear to be a feasible approach. Future trials should ensure their design and analysis is validated by simulation.

How job and family demands impact change in perceived stress: A dyadic study.

PubMed

Smoktunowicz, Ewelina; Cieślak, Roman

2018-01-07

The aim of this two-wave study has been to test the spillover and crossover of job and family demands on changes in perceived stress at work and in the family. Specifically, we proposed that demands from one domain (work or family) spilled over to another domain through interrrole conflict (work-family/family-work conflict) and context-specific self-efficacy. Additionally, we hypothesized that changes in perceived stress were impacted not only by a person's own demands through interrole conflict but also by the demands of one's significant other, in the process of crossover. The study was of dyadic design and it was conducted online, among 130 heterosexual couples, at 2 time points separated by 3 months interval. Hypotheses were verified by means of the path analysis. No support was found for the spillover of job and family demands on changes in perceived stress through interrole conflict and self-efficacy, neither for women nor for men. With regard to the crossover, no support was found for the actor effects, i.e., a person's demands did not impact changes in one's own work- and family-related perceived stress but partial support was found for the partner effects, i.e., women's job demands were associated with men's changes in work and family-related stress through women's work-family conflict, and men's family demands were associated with women's change in family-related perceived stress through men's family-work conflict. The study is a longitudinal test of the Spillover-Crossover model and Work-Home Resources model demonstrating that job and family demands are transmitted across domains and across partners in the intimate relationships through the interrole conflict but the nature of this crossover is different for men and women. Int J Occup Med Environ Health 2018;31(2)199-215. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

A single meal containing raw, crushed garlic influences expression of immunity- and cancer-related genes in whole blood of humans

USDA-ARS?s Scientific Manuscript database

Preclinical and epidemiological studies suggest that garlic intake is inversely associated with the progression of cancer and cardiovascular disease. To probe mechanisms of garlic action in humans, we conducted a randomized crossover feeding trial in which 17 volunteers consumed a garlic-containing...

Critical behavior of modulus of gel

NASA Astrophysics Data System (ADS)

Tokita, Masayuki; Niki, Ryoya; Hikichi, Kunio

1985-09-01

The critical behavior of the shear modulus of casein gel is studied. The shear modulus of casein gel scales with the conductivity exponent in the immediate vicinity of the sol-gel transition point. The asymptotic behavior of the modulus in the region far above the transition point is governed by a different exponent which is much larger than the conductivity exponent. These results are explainable by the crossover behavior of the percolation process. This study shows that the gelation of the casein micelle solution is a realization of the percolation process.

Laboratory- and community-based health outcomes in people with transtibial amputation using crossover and energy-storing prosthetic feet: A randomized crossover trial

PubMed Central

Morgan, Sara J.; McDonald, Cody L.; Halsne, Elizabeth G.; Cheever, Sarah M.; Salem, Rana; Kramer, Patricia A.

2018-01-01

Contemporary prosthetic feet are generally optimized for either daily or high-level activities. Prosthesis users, therefore, often require multiple prostheses to participate in activities that span a range of mobility. Crossover feet (XF) are designed to increase the range of activities that can be performed with a single prosthesis. However, little evidence exists to guide clinical prescription of XF relative to traditional energy storing feet (ESF). The objective of this study was to assess the effects of XF and ESF on health outcomes in people with transtibial amputation. A randomized crossover study was conducted to assess changes in laboratory-based (endurance, perceived exertion, walking performance) and community-based (step activity and self-reported mobility, fatigue, balance confidence, activity restrictions, and satisfaction) outcomes. Twenty-seven participants were fit with XF and ESF prostheses with standardized sockets, interfaces, and suspensions. Participants were not blinded to the intervention, and wore each prosthesis for one month while their steps were counted with an activity monitor. After each accommodation period, participants returned for data collection. Endurance and perceived exertion were measured with the Six-Minute Walk Test and Borg-CR100, respectively. Walking performance was measured using an electronic walkway. Self-reported mobility, fatigue, balance confidence, activity restrictions, and satisfaction were measured with survey instruments. Participants also reported foot preferences upon conclusion of the study. Differences between feet were assessed with a crossover analysis. While using XF, users experienced improvements in most community-based outcomes, including mobility (p = .001), fatigue (p = .001), balance confidence (p = .005), activity restrictions (p = .002), and functional satisfaction (p < .001). Participants also exhibited longer sound side steps in XF compared to ESF (p < .001). Most participants (89%) reported an overall preference for XF; others (11%) reported no preference. Results indicate that XF may be a promising alternative to ESF for people with transtibial amputation who engage in a range of mobility activities. Trial registration: ClinicalTrials.gov NCT02440711 PMID:29414988

Impact of a cognitive rehabilitation intervention on neuropsychiatric symptoms in mild to moderate Alzheimer's disease.

PubMed

Brunelle-Hamann, Laurence; Thivierge, Stéphanie; Simard, Martine

2015-01-01

The main goal of this study was to evaluate the impact of a cognitive rehabilitation programme on 12 behavioural and psychological symptoms of dementia (BPSD) in patients with mild to moderate Alzheimer's disease (AD). This six-month single-blind block-randomised cross-over controlled study was conducted with 15 mild to moderate AD participants and their caregivers. All participants received a four-week home-based cognitive rehabilitation programme to learn/re-learn an instrumental activity of daily living. They were assessed up until three months following the end of the intervention. The Neuropsychiatric Inventory (NPI-12) was employed to evaluate patients' BPSD at seven assessment points during the course of the study. A general linear mixed model analysis performed on the NPI data revealed that aberrant motor behaviours (AMB) increased significantly more in the treatment condition than in the control condition. In addition, both groups registered a significant reduction of delusional symptoms during the second half of the study. Employing a multi-symptom approach to assess participants' BPSD, this cross-over randomised controlled study showed that an individualised cognitive rehabilitation intervention was generally well-tolerated by mild to moderate AD patients. Future cognitive rehabilitation studies conducted with this population should pay attention to AMB symptom changes.

The Effect of Music Therapy Services on Classroom Behaviours of Newly Arrived Refugee Students in Australia--A Pilot Study

ERIC Educational Resources Information Center

Baker, Felicity; Jones, Carolyn

2006-01-01

This pilot study examined the effects of a short-term music therapy program on the classroom behaviours of newly arrived refugee students who were attending an intensive "English as a Second Language" secondary school. A cross-over design with two five-week intervention periods was employed with group music therapy sessions conducted one…

Observation of an emergent coherent state in the iron-based superconductor KFe 2 As 2

DOE PAGES

Yang, Run; Yin, Zhiping; Wang, Yilin; ...

2017-11-14

The ab-plane optical properties of KFe 2As 2 single crystals have been measured over a wide temperature and frequency range. Below T*≃155 K, where this material undergoes an incoherentcoherent crossover, a new coherent response emerges in the optical conductivity. A spectral weight analysis suggests that this new feature originates from high-energy bound states. Below about ≃75 K the scattering rate for this new feature is quadratic in temperature, indicating a Fermiliquid response. Theoretical calculations suggest this crossover is dominated by the d xy orbital. Our results indicate Kondo-type screening is the likely mechanism for the incoherent-coherent crossover in hole-overdoped KFemore » 2As 2.« less

Fenoterol versus salbutamol nebulization in asthma.

PubMed Central

Hockley, B.; Johnson, N. M.

1983-01-01

A double-blind crossover study was conducted in 10 stable asthmatics comparing 5 mg fenoterol with 5 mg salbutamol, both given via a Hudson nebulizer. Although both drugs caused significant bronchodilatation at the doses used, fenoterol had a significantly greater peak effect than salbutamol and its duration of action was 4 hr as opposed to 3 hr. PMID:6353397

Advantages of using voiced questionnaire and image capture application for data collection from a minority group in rural areas along the Thailand-Myanmar border.

PubMed

Monyarit, Siriporn; Pan-ngum, Wirichada; Lawpoolsri, Saranath; Yimsamran, Surapon; Pongnumkul, Suporn; Kaewkungwal, Jaranit; Singhasivanon, Pratap

2014-01-01

To compare the quality of data collection via electronic data capture (EDC) with voiced questionnaire (QNN) and data image capture features using a tablet versus standard paper-based QNN, to assess the user's perception of using the EDC tool, and to compare user satisfaction with the two methods. Randomised cross-over study. Study sites: This study was conducted in two villages along the Thailand-Myanmar border. This study included 30 community health volunteers (CHVs) and 120 Karen hill tribe villagers. Employing a cross-over study design, the CHVs were allocated randomly to two groups, in which they performed interviews in different sequences using EDC and QNN. Data discrepancies were found between the two data-collection methods, when data from the paper-based and image-capture methods were compared, and when conducting skip pattern questions. More than 90% of the CHVs perceived the EDC to be useful and easy to use. Both interviewers and interviewees were more satisfied with the EDC compared with QNN in terms of format, ease of use, and system speed. The EDC can effectively be used as an alternative method to paper-based QNNs for data collection. It produces more accurate data that can be considered evidence-based.

Proton pump inhibitors and vascular function: A prospective cross-over pilot study.

PubMed

Ghebremariam, Yohannes T; Cooke, John P; Khan, Fouzia; Thakker, Rahul N; Chang, Peter; Shah, Nigam H; Nead, Kevin T; Leeper, Nicholas J

2015-08-01

Proton pump inhibitors (PPIs) are commonly used drugs for the treatment of gastric reflux. Recent retrospective cohorts and large database studies have raised concern that the use of PPIs is associated with increased cardiovascular (CV) risk. However, there is no prospective clinical study evaluating whether the use of PPIs directly causes CV harm. We conducted a controlled, open-label, cross-over pilot study among 21 adults aged 18 and older who are healthy (n=11) or have established clinical cardiovascular disease (n=10). Study subjects were assigned to receive a PPI (Prevacid; 30 mg) or a placebo pill once daily for 4 weeks. After a 2-week washout period, participants were crossed over to receive the alternate treatment for the ensuing 4 weeks. Subjects underwent evaluation of vascular function (by the EndoPAT technique) and had plasma levels of asymmetric dimethylarginine (ADMA, an endogenous inhibitor of endothelial function previously implicated in PPI-mediated risk) measured prior to and after each treatment interval. We observed a marginal inverse correlation between the EndoPAT score and plasma levels of ADMA (r = -0.364). Subjects experienced a greater worsening in plasma ADMA levels while on PPI than on placebo, and this trend was more pronounced amongst those subjects with a history of vascular disease. However, these trends did not reach statistical significance, and PPI use was also not associated with an impairment in flow-mediated vasodilation during the course of this study. In conclusion, in this open-label, cross-over pilot study conducted among healthy subjects and coronary disease patients, PPI use did not significantly influence vascular endothelial function. Larger, long-term and blinded trials are needed to mechanistically explain the correlation between PPI use and adverse clinical outcomes, which has recently been reported in retrospective cohort studies. © The Author(s) 2015.

Quasi-experimental designs in practice-based research settings: design and implementation considerations.

PubMed

Handley, Margaret A; Schillinger, Dean; Shiboski, Stephen

2011-01-01

Although randomized controlled trials are often a gold standard for determining intervention effects, in the area of practice-based research (PBR), there are many situations in which individual randomization is not possible. Alternative approaches to evaluating interventions have received increased attention, particularly those that can retain elements of randomization such that they can be considered "controlled" trials. Methodological design elements and practical implementation considerations for two quasi-experimental design approaches that have considerable promise in PBR settings--the stepped-wedge design, and a variant of this design, a wait-list cross-over design, are presented along with a case study from a recent PBR intervention for patients with diabetes. PBR-relevant design features include: creation of a cohort over time that collects control data but allows all participants (clusters or patients) to receive the intervention; staggered introduction of clusters; multiple data collection points; and one-way cross-over into the intervention arm. Practical considerations include: randomization versus stratification, training run in phases; and extended time period for overall study completion. Several design features of practice based research studies can be adapted to local circumstances yet retain elements to improve methodological rigor. Studies that utilize these methods, such as the stepped-wedge design and the wait-list cross-over design, can increase the evidence base for controlled studies conducted within the complex environment of PBR.

An approach to checking case-crossover analyses based on equivalence with time-series methods.

PubMed

Lu, Yun; Symons, James Morel; Geyh, Alison S; Zeger, Scott L

2008-03-01

The case-crossover design has been increasingly applied to epidemiologic investigations of acute adverse health effects associated with ambient air pollution. The correspondence of the design to that of matched case-control studies makes it inferentially appealing for epidemiologic studies. Case-crossover analyses generally use conditional logistic regression modeling. This technique is equivalent to time-series log-linear regression models when there is a common exposure across individuals, as in air pollution studies. Previous methods for obtaining unbiased estimates for case-crossover analyses have assumed that time-varying risk factors are constant within reference windows. In this paper, we rely on the connection between case-crossover and time-series methods to illustrate model-checking procedures from log-linear model diagnostics for time-stratified case-crossover analyses. Additionally, we compare the relative performance of the time-stratified case-crossover approach to time-series methods under 3 simulated scenarios representing different temporal patterns of daily mortality associated with air pollution in Chicago, Illinois, during 1995 and 1996. Whenever a model-be it time-series or case-crossover-fails to account appropriately for fluctuations in time that confound the exposure, the effect estimate will be biased. It is therefore important to perform model-checking in time-stratified case-crossover analyses rather than assume the estimator is unbiased.

Two- to three-dimensional crossover in a dense electron liquid in silicon

NASA Astrophysics Data System (ADS)

Matmon, Guy; Ginossar, Eran; Villis, Byron J.; Kölker, Alex; Lim, Tingbin; Solanki, Hari; Schofield, Steven R.; Curson, Neil J.; Li, Juerong; Murdin, Ben N.; Fisher, Andrew J.; Aeppli, Gabriel

2018-04-01

Doping of silicon via phosphine exposures alternating with molecular beam epitaxy overgrowth is a path to Si:P substrates for conventional microelectronics and quantum information technologies. The technique also provides a well-controlled material for systematic studies of two-dimensional lattices with a half-filled band. We show here that for a dense (ns=2.8 ×1014 cm-2) disordered two-dimensional array of P atoms, the full field magnitude and angle-dependent magnetotransport is remarkably well described by classic weak localization theory with no corrections due to interaction. The two- to three-dimensional crossover seen upon warming can also be interpreted using scaling concepts developed for anistropic three-dimensional materials, which work remarkably except when the applied fields are nearly parallel to the conducting planes.

The effects of foot and facial massage on sleep induction, blood pressure, pulse and respiratory rate: crossover pilot study.

PubMed

Ejindu, Anna

2007-11-01

The study aimed to compare the effects of facial massage with that of foot massage on sleep induction and vital signs of healthy adults and to test a methodology that could be used by a lone researcher in such a study. A randomised within-group crossover pilot study of six healthy female volunteers was conducted. The interventions were a 20min foot and a 20min facial massage using peach-kernel base oil Prunus persica. A drop in systolic blood pressure of 8.5mmHg was recorded immediately after facial massage compared to that of 1mmHg recorded after foot massage. Both treatments were equally effective in reducing subjective levels of alertness during the interventions, with face massage marginally better at producing subjective sleepiness. A lone researcher using these methods would be able objectively to measure vital signs before and after interventions, but not during; and would be able subjectively to measure sleep induction in non-sleep-laboratory contexts.

Effects on Occupants of Enhanced Particle Filtration in a non-problem office environment: A Double-Blind Crossover Intervention Study

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

Mendell, M.J.; Fisk, W.J.; Petersen, M.

1998-06-15

Workers in indoor environments often complain of symptoms, such as eye and nose irritation, headache, and fatigue, which improve away from work. Exposures causing such complaints, sometimes referred to as sick building syndrome, generally have not been identified. Evidence suggests these worker symptoms are related to chemical, microbiological, physical, and psychosocial exposures not well characterized by current methods. Most research in this area has involved cross-sectional studies, which are limited in their abilities to show causal connections. Experimental studies have also been conducted which, by changing one factor at a time to isolate its effects, can demonstrate benefits of anmore » environmental intervention even before exposures or mechanisms are understood. This study was prompted by evidence that particulate contaminants may be related to acute occupant symptoms and discomfort. The objective was to assess, with a double-blind, double crossover intervention design, whether improved removal of small airborne particles by enhanced central filtration would reduce symptoms and discomfort.« less

Elimination of active species crossover in a room temperature, neutral pH, aqueous flow battery using a ceramic NaSICON membrane

NASA Astrophysics Data System (ADS)

Allcorn, Eric; Nagasubramanian, Ganesan; Pratt, Harry D.; Spoerke, Erik; Ingersoll, David

2018-02-01

Flow batteries are an attractive technology for energy storage of grid-scale renewables. However, performance issues related to ion-exchange membrane (IEM) fouling and crossover of species have limited the success of flow batteries. In this work we propose the use of the solid-state sodium-ion conductor NaSICON as an IEM to fully eliminate active species crossover in room temperature, aqueous, neutral pH flow batteries. We measure the room temperature conductivity of NaSICON at 2.83-4.67 mS cm-1 and demonstrate stability of NaSICON in an aqueous electrolyte with conductivity values remaining near 2.5 mS cm-1 after 66 days of exposure. Charge and discharge of a full H-cell battery as well as symmetric cycling in a flow battery configuration using NaSICON as an IEM in both cases demonstrates the capability of the solid-state IEM. Extensive analysis of aged cells through electrochemical impedance spectroscopy (EIS) and UV-vis spectroscopy show no contaminant species having crossed over the NaSICON membrane after 83 days of exposure, yielding an upper limit to the permeability of NaSICON of 4 × 10-10 cm2 min-1. The demonstration of NaSICON as an IEM enables a wide new range of chemistries for application to flow batteries that would previously be impeded by species crossover and associated degradation.

Elimination of active species crossover in a room temperature, neutral pH, aqueous flow battery using a ceramic NaSICON membrane

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

Allcorn, Eric; Nagasubramanian, Ganesan; Pratt, III, Harry D.

Flow batteries are an attractive technology for energy storage of grid-scale renewables. However, performance issues related to ion-exchange membrane (IEM) fouling and crossover of species have limited the success of flow batteries. In this work we propose the use of the solid-state sodium-ion conductor NaSICON as an IEM to fully eliminate active species crossover in room temperature, aqueous, neutral pH flow batteries. We measure the room temperature conductivity of NaSICON at 2.83–4.67 mS cm –1 and demonstrate stability of NaSICON in an aqueous electrolyte with conductivity values remaining near 2.5 mS cm –1 after 66 days of exposure. Charge andmore » discharge of a full H-cell battery as well as symmetric cycling in a flow battery configuration using NaSICON as an IEM in both cases demonstrates the capability of the solid-state IEM. Extensive analysis of aged cells through electrochemical impedance spectroscopy (EIS) and UV–vis spectroscopy show no contaminant species having crossed over the NaSICON membrane after 83 days of exposure, yielding an upper limit to the permeability of NaSICON of 4 × 10 –10 cm 2 min –1. As a result, the demonstration of NaSICON as an IEM enables a wide new range of chemistries for application to flow batteries that would previously be impeded by species crossover and associated degradation.« less

Elimination of active species crossover in a room temperature, neutral pH, aqueous flow battery using a ceramic NaSICON membrane

DOE PAGES

Allcorn, Eric; Nagasubramanian, Ganesan; Pratt, III, Harry D.; ...

2018-01-04

Flow batteries are an attractive technology for energy storage of grid-scale renewables. However, performance issues related to ion-exchange membrane (IEM) fouling and crossover of species have limited the success of flow batteries. In this work we propose the use of the solid-state sodium-ion conductor NaSICON as an IEM to fully eliminate active species crossover in room temperature, aqueous, neutral pH flow batteries. We measure the room temperature conductivity of NaSICON at 2.83–4.67 mS cm –1 and demonstrate stability of NaSICON in an aqueous electrolyte with conductivity values remaining near 2.5 mS cm –1 after 66 days of exposure. Charge andmore » discharge of a full H-cell battery as well as symmetric cycling in a flow battery configuration using NaSICON as an IEM in both cases demonstrates the capability of the solid-state IEM. Extensive analysis of aged cells through electrochemical impedance spectroscopy (EIS) and UV–vis spectroscopy show no contaminant species having crossed over the NaSICON membrane after 83 days of exposure, yielding an upper limit to the permeability of NaSICON of 4 × 10 –10 cm 2 min –1. As a result, the demonstration of NaSICON as an IEM enables a wide new range of chemistries for application to flow batteries that would previously be impeded by species crossover and associated degradation.« less

Luminescence properties of Al0.48In0.52As under hydrostatic pressure

NASA Astrophysics Data System (ADS)

Zhou, Hai-Ping; Sotomayor-Torres, Cliva M.

1992-07-01

The low-temperature photoluminescence (PL) and photoluminescence excitation (PLE) spectra characteristics of Al0.48In0.52As have been studied under high pressure from 1 bar up to 92 kbar. We have obtained, for the first time, the (Gamma) -(Chi) crossover critical pressure Pc (approximately 52.5 +/- 0.5 kbar), the linear pressure coefficients (alpha) (Gamma ) and (alpha) (Chi ) (7.9 meV/kbar and -2.9 meV/kbar, respectively) at helium temperature. By measuring temperature and excitation intensity dependences of the PL spectra together with the PLE spectra, we have demonstrated that the low-temperature luminescence of the Al0.48In0.52As is not excitonic but due to (D degree(s), A degree(s))transitions with a relatively deep acceptor of 68 meV, which occurs in both the direct- and indirect-band gap. We suggest that the shallow donor ground state associated with the (Chi) - and (Gamma) -conduction bands seem to be tied quite rigidly to these conduction bands. Variations in the donor binding energies with the pressure and the direct-indirect crossover seem to be minor.

An Herbal Drug, Gongjin-dan, Ameliorates Acute Fatigue Caused by Short-Term Sleep-Deprivation: A Randomized, Double-Blinded, Placebo-Controlled, Crossover Clinical Trial.

PubMed

Son, Mi Ju; Im, Hwi-Jin; Ku, Boncho; Lee, Jun-Hwan; Jung, So Young; Kim, Young-Eun; Lee, Sung Bae; Kim, Jun Young; Son, Chang-Gue

2018-01-01

Introduction: Gongjin-dan (GJD) is an herbal drug commonly used in Korea and China to combat fatigue, but there are only few clinical studies on its effectiveness and experimental studies on its mechanism of action, and no randomized controlled trial of GJD on the efficacy and mechanism of action has been reported. Here, we performed an exploratory study to evaluate both questions regarding GJD use in humans. Methods: A randomized, double-blinded, placebo-controlled, crossover clinical trial was conducted in the Republic of Korea. Healthy male participants were recruited and randomly allocated to groups receiving GJD-placebo or placebo-GJD in sequence. Fatigue was artificially induced by sleep deprivation for 2 nights. The primary outcome was a change in serum cortisol level; levels of biomarkers for stress hormones as well as oxidative stress and immunologic factors were also assessed, and questionnaires on fatigue and sleep quality were conducted. Results: Twelve and 11 participants were assigned to the GJD-placebo and placebo-GJD groups, respectively. Of all 23 participants, depending on crossover design, we analyzed a total of 20 participants for GJD, and 21 for placebo. An increase in serum cortisol appeared to be attenuated by GJD administration ( p = 0.25), but the effect was not statistically significant; a similar pattern was observed in salivary cortisol levels ( p = 0.14). Overall, GJD showed a tendency to reduce fatigue according to the Brief Fatigue Inventory (BFI, p = 0.07) and the Fatigue Severity Scale (FSS, p = 0.13) questionnaires. BFI and FSS scores in the first stage (before the crossover), however, were significantly improved (BFI, p = 0.02; FSS, p = 0.05) after GJD treatment (relative to placebo). GJD also seemed to improve sleep quality as assessed by the Leeds Sleep Evaluation Questionnaire ( p = 0.06), with a significant improvement specifically in the condition "Getting To Sleep" ( p = 0.02). Five participants experienced minor adverse events, but no adverse events were specific to the GJD administration period. Conclusions: This trial produced the first clinical evidence that GJD might have anti-fatigue properties, especially under sleep deprivation; however, the investigation of cortisol-mediated mechanisms requires further larger-scale studies in the future. World Health Organization International Clinical Trials Registry Platform KCT0001681 (http://apps.who.int/trialsearch/Trial2.aspx?TrialID=KCT0001681).

Shell structures in aluminum nanocontacts at elevated temperatures

PubMed Central

2012-01-01

Aluminum nanocontact conductance histograms are studied experimentally from room temperature up to near the bulk melting point. The dominant stable configurations for this metal show a very early crossover from shell structures at low wire diameters to ionic subshell structures at larger diameters. At these larger radii, the favorable structures are temperature-independent and consistent with those expected for ionic subshell (faceted) formations in face-centered cubic geometries. When approaching the bulk melting temperature, these local stability structures become less pronounced as shown by the vanishing conductance histogram peak structure. PMID:22325572

2-Methacryloyloxyethyl phosphorylcholine (MPC)-polymer suppresses an increase of oral bacteria: a single-blind, crossover clinical trial.

PubMed

Fujiwara, Natsumi; Yumoto, Hiromichi; Miyamoto, Koji; Hirota, Katsuhiko; Nakae, Hiromi; Tanaka, Saya; Murakami, Keiji; Kudo, Yasusei; Ozaki, Kazumi; Miyake, Yoichiro

2018-05-16

The biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC)-polymers, which mimic a biomembrane, reduce protein adsorption and bacterial adhesion and inhibit cell attachment. The aim of this study is to clarify whether MPC-polymer can suppress the bacterial adherence in oral cavity by a crossover design. We also investigated the number of Fusobacterium nucleatum, which is the key bacterium forming dental plaque, in clinical samples. This study was a randomized, placebo-controlled, single-blind, crossover study, with two treatment periods separated by a 2-week washout period. We conducted clinical trial with 20 healthy subjects to evaluate the effect of 5% MPC-polymer mouthwash after 5 h on oral microflora. PBS was used as a control. The bacterial number in the gargling sample before and after intervention was counted by an electronic bacterial counter and a culture method. DNA amounts of total bacteria and F. nucleatum were examined by q-PCR. The numbers of total bacteria and oral streptcocci after 5 h of 5% MPC-polymer treatment significantly decreased, compared to the control group. Moreover, the DNA amounts of total bacteria and F. nucleatum significantly decreased by 5% MPC-polymer mouthwash. We suggest that MPC-polymer coating in the oral cavity may suppress the oral bacterial adherence. MPC-polymer can be a potent compound for the control of oral microflora to prevent oral infection.

Studies on Methanol Crossover in Liquid-Feed Direct Methanol Pem Fuel Cells

NASA Technical Reports Server (NTRS)

Narayanan, S. R.

1995-01-01

The performance of liquid feed direct methanol fuel cells using various types of Nafion membranes as the solid polymer electrolyte have been studied. The rate of fuel crossover and electrical performance has been measured for cells with Nafion membranes of various thicknesses and equivalent weights. The crossover rate is found to decrease with increasing thickness and applied current. The dependence of crossover rate on current density can be understood in terms of a simple linear diffusion model which suggests that the crossover rate can be influenced by the electrode structure in addition to the membrane. The studies suggest that Nafion EW 1500 is a very promising alternate to Nafion EW 1100 for direct methanol fuel cells.

Effect of sex, age and genetics on crossover interference in cattle

PubMed Central

Wang, Zhiying; Shen, Botong; Jiang, Jicai; Li, Jinquan; Ma, Li

2016-01-01

Crossovers generated by homologous recombination ensure proper chromosome segregation during meiosis. Crossover interference results in chiasmata being more evenly distributed along chromosomes, but the mechanism underlying crossover interference remains elusive. Based on large pedigrees of Holstein and Jersey cattle with genotype data, we extracted three-generation families, including 147,327 male and 71,687 female meioses in Holstein, and 108,163 male and 37,008 female meioses in Jersey, respectively. We identified crossovers in these meioses and fitted the Housworth-Stahl “interference-escape” model to study crossover interference patterns in the cattle genome. Our result reveals that the degree of crossover interference is stronger in females than in males. We found evidence for inter-chromosomal variation in the level of crossover interference, with smaller chromosomes exhibiting stronger interference. In addition, crossover interference levels decreased with maternal age. Finally, sex-specific GWAS analyses identified one locus near the NEK9 gene on chromosome 10 to have a significant effect on crossover interference levels. This locus has been previously associated with recombination rate in cattle. Collectively, this large-scale analysis provided a comprehensive description of crossover interference across chromosome, sex and age groups, identified associated candidate genes, and produced useful insights into the mechanism of crossover interference. PMID:27892966

What's Mine Is Yours: The Crossover of Day-Specific Self-Esteem

ERIC Educational Resources Information Center

Neff, Angela; Sonnentag, Sabine; Niessen, Cornelia; Unger, Dana

2012-01-01

This diary study examines the daily crossover of self-esteem within working couples. By integrating self-esteem research into the crossover framework, we hypothesized that the day-specific self-esteem experienced by one partner after work crosses over to the other partner. Furthermore, we proposed that this daily crossover process is moderated by…

Field-induced superconducting phase of FeSe in the BCS-BEC cross-over

PubMed Central

Kasahara, Shigeru; Watashige, Tatsuya; Hanaguri, Tetsuo; Kohsaka, Yuhki; Yamashita, Takuya; Shimoyama, Yusuke; Mizukami, Yuta; Endo, Ryota; Ikeda, Hiroaki; Aoyama, Kazushi; Terashima, Taichi; Uji, Shinya; Wolf, Thomas; von Löhneysen, Hilbert; Shibauchi, Takasada; Matsuda, Yuji

2014-01-01

Fermi systems in the cross-over regime between weakly coupled Bardeen–Cooper–Schrieffer (BCS) and strongly coupled Bose–Einstein-condensate (BEC) limits are among the most fascinating objects to study the behavior of an assembly of strongly interacting particles. The physics of this cross-over has been of considerable interest both in the fields of condensed matter and ultracold atoms. One of the most challenging issues in this regime is the effect of large spin imbalance on a Fermi system under magnetic fields. Although several exotic physical properties have been predicted theoretically, the experimental realization of such an unusual superconducting state has not been achieved so far. Here we show that pure single crystals of superconducting FeSe offer the possibility to enter the previously unexplored realm where the three energies, Fermi energy εF, superconducting gap Δ, and Zeeman energy, become comparable. Through the superfluid response, transport, thermoelectric response, and spectroscopic-imaging scanning tunneling microscopy, we demonstrate that εF of FeSe is extremely small, with the ratio Δ/εF∼1(∼0.3) in the electron (hole) band. Moreover, thermal-conductivity measurements give evidence of a distinct phase line below the upper critical field, where the Zeeman energy becomes comparable to εF and Δ. The observation of this field-induced phase provides insights into previously poorly understood aspects of the highly spin-polarized Fermi liquid in the BCS-BEC cross-over regime. PMID:25378706

Zero temperature coefficient of resistance of the electrical-breakdown path in ultrathin hafnia

NASA Astrophysics Data System (ADS)

Zhang, H. Z.; Ang, D. S.

2017-09-01

The recent widespread attention on the use of the non-volatile resistance switching property of a microscopic oxide region after electrical breakdown for memory applications has prompted basic interest in the conduction properties of the breakdown region. Here, we report an interesting crossover from a negative to a positive temperature dependence of the resistance of a breakdown region in ultrathin hafnia as the applied voltage is increased. As a consequence, a near-zero temperature coefficient of resistance is obtained at the crossover voltage. The behavior may be modeled by (1) a tunneling-limited transport involving two farthest-spaced defects along the conduction path at low voltage and (2) a subsequent transition to a scattering-limited transport after the barrier is overcome by a larger applied voltage.

Spacer type mediated tunable spin crossover (SCO) characteristics of pyrene decorated 2,6-bis(pyrazol-1-yl)pyridine (bpp) based Fe(ii) molecular spintronic modules.

PubMed

Kumar, Kuppusamy Senthil; Šalitroš, Ivan; Moreno-Pineda, Eufemio; Ruben, Mario

2017-08-14

A simple "isomer-like" variation of the spacer group in a set of Fe(ii) spin crossover (SCO) complexes designed to probe spin state dependence of electrical conductivity in graphene-based molecular spintronic junctions led to the observation of remarkable variations in the thermal- and light-induced magnetic characteristics, paving a simple route for the design of functional SCO complexes with different temperature switching regimes based on a 2,6-bis(pyrazol-1-yl)pyridine ligand skeleton.

Relationship Between Unusual High-Temperature Fatigue Crack Growth Threshold Behavior in Superalloys and Sudden Failure Mode Transitions

NASA Technical Reports Server (NTRS)

Telesman, J.; Smith, T. M.; Gabb, T. P.; Ring, A. J.

2017-01-01

An investigation of high temperature cyclic fatigue crack growth (FCG) threshold behavior of two advanced nickel disk alloys was conducted. The focus of the study was the unusual crossover effect in the near-threshold region of these type of alloys where conditions which produce higher crack growth rates in the Paris regime, produce higher resistance to crack growth in the near threshold regime. It was shown that this crossover effect is associated with a sudden change in the fatigue failure mode from a predominant transgranular mode in the Paris regime to fully intergranular mode in the threshold fatigue crack growth region. This type of a sudden change in the fracture mechanisms has not been previously reported and is surprising considering that intergranular failure is typically associated with faster crack growth rates and not the slow FCG rates of the near-threshold regime. By characterizing this behavior as a function of test temperature, environment and cyclic frequency, it was determined that both the crossover effect and the onset of intergranular failure are caused by environmentally driven mechanisms which have not as yet been fully identified. A plausible explanation for the observed behavior is proposed.

Effectiveness of Cognitive-Functional (Cog-Fun) occupational therapy intervention for young children with attention deficit hyperactivity disorder: a controlled study.

PubMed

Maeir, Adina; Fisher, Orit; Bar-Ilan, Ruthie Traub; Boas, Naomi; Berger, Itai; Landau, Yael E

2014-01-01

The purpose of this study was to examine the effectiveness of the Cognitive-Functional (Cog-Fun) intervention for young children with attention deficit hyperactivity disorder (ADHD). Nineteen children ages 5-7 yr diagnosed with ADHD were allocated to treatment and wait-list control groups. After the 12-wk intervention, the control group was crossed over to treatment. Follow-up was conducted 3 mo after treatment. Outcome measures included the Behavior Rating Inventory of Executive Function and the Canadian Occupational Performance Measure. Before crossover, significant differences were found between groups in change scores on the outcome measures. After crossover, no significant differences were found in treatment effects, and significant moderate to large treatment effects were found for both COPM and BRIEF scores. Treatment gains were maintained at follow-up. The study supports the effectiveness of the Cog-Fun intervention in improving occupational performance and executive functions in daily life for young children with ADHD. Copyright © 2014 by the American Occupational Therapy Association, Inc.

Spin crossover and Mott—Hubbard transition under high pressure and high temperature in the low mantle of the Earth

NASA Astrophysics Data System (ADS)

Ovchinnikov, S. G.; Ovchinnikova, T. M.; Plotkin, V. V.; Dyad'kov, P. G.

2015-11-01

Effect of high pressure induced spin crossover on the magnetic, electronic and structural properties of the minerals forming the Earth's low mantle is discussed. The low temperature P, T phase diagram of ferropericlase has the quantum phase transition point Pc = 56 GPa at T = 0 confirmed recently by the synchrotron Mössbauer spectroscopy. The LDA+GTB calculated phase diagram describes the experimental data. Its extension to the high temperature resulted earlier in prediction of the metallic properties of the Earth's mantle at the depth 1400 km < h < 1800 km. Estimation of the electrical conductivity based on the percolation theory is given. We discuss also the thermodynamic properties and structural anomalies resulting from the spin crossover and metal-insulator transition and compare them with the experimental seismic and geomagnetic field data.

Prominent metallic surface conduction and the singular magnetic response of topological Dirac fermion in three-dimensional topological insulator Bi1.5Sb0.5Te1.7Se1.3.

PubMed

Dutta, Prithwish; Pariari, Arnab; Mandal, Prabhat

2017-07-07

We report semiconductor to metal-like crossover in the temperature dependence of resistivity (ρ) due to the switching of charge transport from bulk to surface channel in three-dimensional topological insulator Bi 1.5 Sb 0.5 Te 1.7 Se 1.3 . Unlike earlier studies, a much sharper drop in ρ(T) is observed below the crossover temperature due to the dominant surface conduction. Remarkably, the resistivity of the conducting surface channel follows a rarely observable T 2 dependence at low temperature, as predicted theoretically for a two-dimensional Fermi liquid system. The field dependence of magnetization shows a cusp-like paramagnetic peak in the susceptibility (χ) at zero field over the diamagnetic background. The peak is found to be robust against temperature and χ decays linearly with the field from its zero-field value. This unique behavior of the χ is associated with the spin-momentum locked topological surface state in Bi 1.5 Sb 0.5 Te 1.7 Se 1.3 . The reconstruction of the surface state with time is clearly reflected through the reduction of the peak height with the age of the sample.

Surface Charge Effects on the Electro-Orientation of Insulating Nanotubes in Aqueous Electrolytes

NASA Astrophysics Data System (ADS)

Cetindag, Semih; Tiwari, Bishnu; Zhang, Dongyan; Yap, Yoke Khin; Kim, Sangil; Shan, Jerry W.

2017-11-01

While the alignment of electrically conductive nanowires and nanotubes by electric fields in liquid solution has been well studied, much less is known about the electro-orientation of insulating 1D particles, such as boron-nitride nanotubes (BNNTs). Here, we demonstrate for the first time the electro-orientation of individual insulating BNNTs in aqueous KCl solutions under AC fields. Comparison to theory indicates that the observed frequency response is not related to the crossover for Maxwell-Wagner interfacial polarization. Instead, the cross-over frequency in the low-frequency regime scales as the square root of solution conductivity, indicating that alignment is associated with the formation and motion of an electrical double layer (EDL), much like induced-charge electro-osmosis for a conducting particle. However, the mechanism for the formation of the EDL is presumably different for insulating particles like BNNTs as compared to conductors. By varying the surface charge of the particle by changing pH, we show that the alignment rate increases with increasing surface charge, and is likely a result of counter-ion migration and EDL polarization under the influence of applied electric field. Thus, particle surface charge (large Dukhin number) is believed to play a vital role in the electro-orientation of insulating particles in aqueous solutions. NSF CBET-1604931 and NSF DMR-1261910.

Efficacy and safety of mini-dose glucagon for treatment of nonsevere hypoglycemia in adults with type 1 diabetes

USDA-ARS?s Scientific Manuscript database

The purpose of this study was to evaluate low-dose glucagon to treat mild hypoglycemia in ambulatory adults with type 1 diabetes (T1D). This was a randomized crossover trial (two 3-week periods) conducted at five U.S. diabetes clinics. Twenty adults with T1D using an insulin pump and continuous gluc...

Stress Crossover in Newlywed Marriage: A Longitudinal and Dyadic Perspective

ERIC Educational Resources Information Center

Neff, Lisa A.; Karney, Benjamin R.

2007-01-01

Studies of stress and marital quality often assess stress as an intrapersonal phenomenon, examining how spouses' stress may influence their own relationship well-being. Yet spouses' stress also may influence partners' relationship evaluations, a phenomenon referred to as stress crossover. This study examined stress crossover, and conditions that…

A novel approach to model hydraulic and electrical conductivity in fractal porous media

NASA Astrophysics Data System (ADS)

Ghanbarian, B.; Daigle, H.; Sahimi, M.

2014-12-01

Accurate prediction of conductivity in partially-saturated porous media has broad applications in various phenomena in porous media, and has been studied intensively since the 1940s by petroleum, chemical and civil engineers, and hydrologists. Many of the models developed in the past are based on the bundle of capillary tubes. In addition, pore network models have also been developed for simulating multiphase fluid flow in porous media and computing the conductivity in unsaturated porous media. In this study, we propose a novel approach using concepts from the effective-medium approximation (EMA) and percolation theory to model hydraulic and electrical conductivity in fractal porous media whose pore-size distributions exhibit power-law scaling. In our approach, the EMA, originally developed for predicting electrical conductivity of composite materials, is used to predict the effective conductivity, from complete saturation to some intermediate water content that represents a crossover point. Below the crossover water content, but still above a critical saturation (percolation threshold), a universal scaling predicted by percolation theory, a power law that expresses the dependence of the conductivity on the water content (less a critical water saturation) with an exponent of 2, is invoked to describe the effective conductivity. In order to evaluate the accuracy of the approach, experimental data were used from the literature. The predicted hydraulic conductivities for most cases are in excellent agreement with the data. In a few cases the theory underestimates the hydraulic conductivities, which correspond to porous media with very broad pore-size distribution in which the largest pore radius is more than 7 orders of magnitude greater than the smallest one. The approach is also used to predict the saturation dependence of the electrical conductivity for experiments in which capillary pressure data are available. The results indicate that the universal scaling of the electrical conductivity is valid from the percolation threshold all the way up to the complete saturation point. Our results confirm those reported previously by Ewing and Hunt (2006) who argued that the electrical conductivity should follow universal scaling over the entire range of saturation.

Dramatic improvement in water retention and proton conductivity in electrically aligned functionalized CNT/SPEEK nanohybrid PEM.

PubMed

Gahlot, Swati; Kulshrestha, Vaibhav

2015-01-14

Nanohybrid membranes of electrically aligned functionalized carbon nanotube f CNT with sulfonated poly ether ether ketone (SPEEK) have been successfully prepared by solution casting. Functionalization of CNTs was done through a carboxylation and sulfonation route. Further, a constant electric field (500 V·cm(-2)) has been applied to align CNTs in the same direction during the membrane drying process. All the membranes are characterized chemically, thermally, and mechanically by the means of FTIR, DSC, DMA, UTM, SEM, TEM, and AFM techniques. Intermolecular interactions between the components in hybrid membranes are established by FTIR. Physicochemical measurements were done to analyze membrane stability. Membranes are evaluated for proton conductivity (30-90 °C) and methanol crossover resistance to reveal their potential for direct methanol fuel cell application. Incorporation of f CNT reasonably increases the ion-exchange capacity, water retention, and proton conductivity while it reduces the methanol permeability. The maximum proton conductivity has been found in the S-sCNT-5 nanohybrid PEM with higher methanol crossover resistance. The prepared membranes can be also used for electrode material for fuel cells and batteries.

Crossover versus mutation: a comparative analysis of the evolutionary strategy of genetic algorithms applied to combinatorial optimization problems.

PubMed

Osaba, E; Carballedo, R; Diaz, F; Onieva, E; de la Iglesia, I; Perallos, A

2014-01-01

Since their first formulation, genetic algorithms (GAs) have been one of the most widely used techniques to solve combinatorial optimization problems. The basic structure of the GAs is known by the scientific community, and thanks to their easy application and good performance, GAs are the focus of a lot of research works annually. Although throughout history there have been many studies analyzing various concepts of GAs, in the literature there are few studies that analyze objectively the influence of using blind crossover operators for combinatorial optimization problems. For this reason, in this paper a deep study on the influence of using them is conducted. The study is based on a comparison of nine techniques applied to four well-known combinatorial optimization problems. Six of the techniques are GAs with different configurations, and the remaining three are evolutionary algorithms that focus exclusively on the mutation process. Finally, to perform a reliable comparison of these results, a statistical study of them is made, performing the normal distribution z-test.

Crossover versus Mutation: A Comparative Analysis of the Evolutionary Strategy of Genetic Algorithms Applied to Combinatorial Optimization Problems

PubMed Central

Osaba, E.; Carballedo, R.; Diaz, F.; Onieva, E.; de la Iglesia, I.; Perallos, A.

2014-01-01

Since their first formulation, genetic algorithms (GAs) have been one of the most widely used techniques to solve combinatorial optimization problems. The basic structure of the GAs is known by the scientific community, and thanks to their easy application and good performance, GAs are the focus of a lot of research works annually. Although throughout history there have been many studies analyzing various concepts of GAs, in the literature there are few studies that analyze objectively the influence of using blind crossover operators for combinatorial optimization problems. For this reason, in this paper a deep study on the influence of using them is conducted. The study is based on a comparison of nine techniques applied to four well-known combinatorial optimization problems. Six of the techniques are GAs with different configurations, and the remaining three are evolutionary algorithms that focus exclusively on the mutation process. Finally, to perform a reliable comparison of these results, a statistical study of them is made, performing the normal distribution z-test. PMID:25165731

Influence of fractal substructures of the percolating cluster on transferring processes in macroscopically disordered environments

NASA Astrophysics Data System (ADS)

Kolesnikov, B. P.

2017-11-01

The presented work belongs to the issue of searching for the effective kinetic properties of macroscopically disordered environments (MDE). These properties characterize MDE in general on the sizes which significantly exceed the sizes of macro inhomogeneity. The structure of MDE is considered as a complex of interpenetrating percolating and finite clusters consolidated from homonymous components, topological characteristics of which influence on the properties of the whole environment. The influence of percolating clusters’ fractal substructures (backbone, skeleton of backbone, red bonds) on the transfer processes during crossover (a structure transition from fractal to homogeneous condition) is investigated based on the offered mathematical approach for finding the effective conductivity of MDEs and on the percolating cluster model. The nature of the change of the critical conductivity index t during crossover from the characteristic value for the area close to percolation threshold to the value corresponded to homogeneous condition is demonstrated. The offered model describes the transfer processes in MDE with the finite conductivity relation of «conductive» and «low conductive» phases above and below percolation threshold and in smearing area (an analogue of a blur area of the second-order phase transfer).

Diverging diamond interchange performance evaluation (I-44 and Route 13)

DOT National Transportation Integrated Search

2011-02-01

Performance evaluation was conducted on the first diverging diamond interchange (DDI) or double : crossover interchange (DCD) constructed in the United States. This evaluation assessed traffic operations, safety and : public perceptions t...

The association between urban tree cover and gun assault: A case-control and case-crossover study

Treesearch

Michelle C. Kondo; Eugenia C. South; Charles C. Branas; Therese S. Richmond; Douglas J. Wiebe

2017-01-01

Green space and vegetation may play a protective role against urban violence. We investigated whether being near urban tree cover during outdoor activities was related to being assaulted with a gun. We conducted geographic information systems–assisted interviews with boys andmen aged 10–24 years in Philadelphia, Pennsylvania, including 135 patients who had been shot...

Low-temperature emission of Al0.48In0.52As under high pressures

NASA Astrophysics Data System (ADS)

Zhou, H. P.; Sotomayor Torres, C. M.

1994-04-01

We investigated the low-temperature emission of Al0.48In0.52As under high pressures from 1 bar up to 92 kbar, paying special attention to the changes in luminescence mechanisms that occur concurrently with the crossover between the Γ- and the X-related states. By investigating the temperature and excitation power dependence of the photoluminescence together with the photoluminescence excitation, we demonstrate the low-temperature emission of Al0.48In0.52As is due to neutral donor-acceptor-pair (D0,A0) transitions with a relatively deep acceptor. This occurs in both the Γ- and the X-related states. We suggest the shallow donor ground states associated with the X and the Γ conduction bands seem to be tied quite rigidly to these conduction bands. Variations in the donor binding energies with the pressure and the Γ-X related state crossover seem to be minor. The linear pressure coefficients αΓ and αX of the (D0,A0) related to the Γ and the X levels in the conduction band are 7.9±0.1 and -2.9±0.1 meV/kbar, respectively. The Γ-X related state crossover occurs at ˜52.5±0.5 kbar at 2 K. The direct band gap EΓg and the indirect band gap Exg of Al0.48In0.52As are ˜1.61 and ˜2.17 eV at 1 bar and 2 K, respectively.

Elucidating the DEP phenomena using a volumetric polarization approach with consideration of the electric double layer

PubMed Central

Brcka, Jozef; Faguet, Jacques; Zhang, Guigen

2017-01-01

Dielectrophoretic (DEP) phenomena have been explored to great success for various applications like particle sorting and separation. To elucidate the underlying mechanism and quantify the DEP force experienced by particles, the point-dipole and Maxwell Stress Tensor (MST) methods are commonly used. However, both methods exhibit their own limitations. For example, the point-dipole method is unable to fully capture the essence of particle-particle interactions and the MST method is not suitable for particles of non-homogeneous property. Moreover, both methods fare poorly when it comes to explaining DEP phenomena such as the dependence of crossover frequency on medium conductivity. To address these limitations, the authors have developed a new method, termed volumetric-integration method, with the aid of computational implementation, to reexamine the DEP phenomena, elucidate the governing mechanism, and quantify the DEP force. The effect of an electric double layer (EDL) on particles' crossover behavior is dealt with through consideration of the EDL structure along with surface ionic/molecular adsorption, unlike in other methods, where the EDL is accounted for through simply assigning a surface conductance value to the particles. For validation, by comparing with literature experimental data, the authors show that the new method can quantify the DEP force on not only homogeneous particles but also non-homogeneous ones, and predict particle-particle interactions fairly accurately. Moreover, the authors also show that the predicted dependence of crossover frequency on medium conductivity and particle size agrees very well with experimental measurements. PMID:28396710

A case-crossover study of transient risk factors influence on occupational injuries: a study protocol based on a review of previous studies.

PubMed

Oesterlund, Anna H; Lander, Flemming; Lauritsen, Jens

2016-10-01

The occupational injury incident rate remains relatively high in the European Union. The case-crossover study gives a unique opportunity to study transient risk factors that normally would be very difficult to approach. Studies like this have been carried out in both America and Asia, but so far no relevant research has been conducted in Europe. Case-crossover studies of occupational injuries were collected from PubMed and Embase and read through. Previous experiences concerning method, exposure and outcome, time-related measurements and construction of the questionnaire were taken into account in the preparation of a pilot study. Consequently, experiences from the pilot study were used to design the study protocol. Approximately 2000 patients with an occupational injury will be recruited from the emergency departments in Herning and Odense, Denmark. A standardised questionnaire will be used to collect basic demographic data and information on eight transient risk factors. Based on previous studies and knowledge on occupational injuries the transient risk factors we chose to examine were: time pressure, performing a task with a different method/using unaccustomed technique, change in working surroundings, using a phone, disagreement, feeling ill, being distracted and using malfunctioning machinery/tools or work material. Exposure time 'just before the injury' will be compared with two control periods, 'previous day at the same time of the injury' (pair match) and the previous work week (usual frequency). This study protocol describes a unique opportunity to calculate the effect of transient risk factors on occupational injuries in a European setting. 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/

Peer Assessment Enhances Student Learning: The Results of a Matched Randomized Crossover Experiment in a College Statistics Class.

PubMed

Sun, Dennis L; Harris, Naftali; Walther, Guenther; Baiocchi, Michael

2015-01-01

Feedback has a powerful influence on learning, but it is also expensive to provide. In large classes it may even be impossible for instructors to provide individualized feedback. Peer assessment is one way to provide personalized feedback that scales to large classes. Besides these obvious logistical benefits, it has been conjectured that students also learn from the practice of peer assessment. However, this has never been conclusively demonstrated. Using an online educational platform that we developed, we conducted an in-class matched-set, randomized crossover experiment with high power to detect small effects. We establish that peer assessment causes a small but significant gain in student achievement. Our study also demonstrates the potential of web-based platforms to facilitate the design of high-quality experiments to identify small effects that were previously not detectable.

Effect of Kangaroo mother care in reducing pain due to heel prick among preterm neonates: a crossover trial.

PubMed

Chidambaram, Ambika Gnanam; Manjula, S; Adhisivam, B; Bhat, B Vishnu

2014-03-01

Preterm neonates undergo several painful procedures in NICU including heel prick for blood sugar monitoring. Nonpharmacological interventions have been tried to decrease this procedural pain. There are only few studies on Kangaroo mother care (KMC) in reducing pain among preterm neonates. This crossover trial was conducted at a tertiary care teaching hospital in south India. Premature Infant Pain Profile (PIPP) related to heel prick was assessed in 50 preterm neonates undergoing KMC and compared with 50 preterm babies without KMC. PIPP scores at 15 minutes and 30 minutes after heel prick were significantly less in KMC group compared to control group. Mean PIPP difference between baseline and 30 minutes after heel prick was also significantly low in KMC group compared to control group. KMC is effective in reducing pain due to heel prick among preterm babies.

Recruitment and retention of young women into nutrition research studies: practical considerations.

PubMed

Leonard, Alecia; Hutchesson, Melinda; Patterson, Amanda; Chalmers, Kerry; Collins, Clare

2014-01-16

Successful recruitment and retention of participants into research studies is critical for optimising internal and external validity. Research into diet and lifestyle of young women is important due to the physiological transitions experienced at this life stage. This paper aims to evaluate data related to recruitment and retention across three research studies with young women, and present practical advice related to recruiting and retaining young women in order to optimise study quality within nutrition research. Recruitment and retention strategies used in three nutrition studies that targeted young women (18 to 35 years) were critiqued. A randomised controlled trial (RCT), a crossover validation study and a cross-sectional survey were conducted at the University of Newcastle, Australia between 2010 and 2013Successful recruitment was defined as maximum recruitment relative to time. Retention was assessed as maximum participants remaining enrolled at study completion. Recruitment approaches included notice boards, web and social network sites (Facebook and Twitter), with social media most successful in recruitment. The online survey had the highest recruitment in the shortest time-frame (751 participants in one month). Email, phone and text message were used in study one (RCT) and study two (crossover validation) and assisted in low attrition rates, with 93% and 75.7% completing the RCT and crossover validation study respectively. Of those who did not complete the RCT, reported reasons were: being too busy; and having an unrelated illness. Recruiting young women into nutrition research is challenging. Use of social media enhances recruitment, while Email, phone and text message contact improves retention within interventions. Further research comparing strategies to optimise recruitment and retention in young women, including flexible testing times, reminders and incentives is warranted.

Threshold Levels of Infant and Under-Five Mortality for Crossover between Life Expectancies at Ages Zero, One and Five in India: A Decomposition Analysis.

PubMed

Dubey, Manisha; Ram, Usha; Ram, Faujdar

2015-01-01

Under the prevailing conditions of imbalanced life table and historic gender discrimination in India, our study examines crossover between life expectancies at ages zero, one and five years for India and quantifies the relative share of infant and under-five mortality towards this crossover. We estimate threshold levels of infant and under-five mortality required for crossover using age specific death rates during 1981-2009 for 16 Indian states by sex (comprising of India's 90% population in 2011). Kitagawa decomposition equations were used to analyse relative share of infant and under-five mortality towards crossover. India experienced crossover between life expectancies at ages zero and five in 2004 for menand in 2009 for women; eleven and nine Indian states have experienced this crossover for men and women, respectively. Men usually experienced crossover four years earlier than the women. Improvements in mortality below ages five have mostly contributed towards this crossover. Life expectancy at age one exceeds that at age zero for both men and women in India except for Kerala (the only state to experience this crossover in 2000 for men and 1999 for women). For India, using life expectancy at age zero and under-five mortality rate together may be more meaningful to measure overall health of its people until the crossover. Delayed crossover for women, despite higher life expectancy at birth than for men reiterates that Indian women are still disadvantaged and hence use of life expectancies at ages zero, one and five become important for India. Greater programmatic efforts to control leading causes of death during the first month and 1-59 months in high child mortality areas can help India to attain this crossover early.

Adherence to Point-of-Use Water Treatment over Short-Term Implementation: Parallel Crossover Trials of Flocculation-Disinfection Sachets in Pakistan and Zambia.

PubMed

Shaheed, A; Rathore, S; Bastable, A; Bruce, J; Cairncross, S; Brown, J

2018-06-05

The health benefits of point-of-use (POU) water treatment can only be realized through high adherence: correct, consistent, and sustained use. We conducted parallel randomized, longitudinal crossover trials measuring short-term adherence to two single-use flocculant-disinfectant sachets in Pakistan and Zambia. In both trials, adherence declined sharply for both products over the eight week surveillance periods, with overall lower adherence to both products in Zambia. There was no significant difference in adherence between the two products. Estimated median daily production of treated water dropped over the crossover period from 2.5 to 1.4 L person -1 day -1 (46% decline) in Pakistan and from 1.4 to 1.1 L person -1 day -1 (21% decline) in Zambia. The percentage of surveillance points with detectable total chlorine in household drinking water declined from 70% to 49% in Pakistan and rose marginally from 28% to 30% in Zambia. The relatively low and decreasing adherence observed in this study suggests that these products would have provided little protection from waterborne disease risk in these settings. Our findings underscore the challenge of achieving high adherence to POU water treatment, even under conditions of short-term adoption with intensive follow-up.

Dielectrophoretic spectroscopy using a microscopic electrode array

NASA Astrophysics Data System (ADS)

Kirmani, Syed Abdul Mannan; Gudagunti, Fleming Dackson; Velmanickam, Logeeshan; Nawarathna, Dharmakeerthi; Lima, Ivan T.

2017-02-01

Dielectrophoresis (DEP) is a commonly used technique in biomedical engineering to manipulate biomolecules. DEP is defined as the force acting on dielectric particles when they are exposed to non-uniform electric fields. DEP effect can be divided in three categories: positive (dielectric particles are attracted to the electrodes), negative, and zero force DEP. The cross-over frequency is the frequency in which the DEP force is equal to zero. The cross-over frequency depends on the conductivity and the permittivity of the particles and of the suspended medium. The DEP cross-over frequency has been utilized in detecting/quantifying biomolecules. A manual procedure is commonly used to estimate the cross-over frequency of biomolecules. Therefore, the accuracy of this detection method is significantly limited. To address this issue, we designed and tested an automated procedure to carry out DEP spectroscopy in dielectric particles dissolved in a biological buffer solution. Our method efficiently measures the effect of the DEP force through a live video feed from the microscope camera and performs real-time image processing. It records the change in the fluorescence emission as the system automatically scans the electric frequency of the function generator over a specified time interval. We demonstrated the effectiveness of the method by extracting the crossover frequencies and the DEP spectrum of polystyrene beads with blue color dye (1000 nm diameter) and green fluorescent polystyrene beads with 500 nm diameter using this procedure. This approach can lead to the development of a biosensor with significantly higher sensitivity than existing detection methods.

Efficacy and safety of creatine supplementation in juvenile dermatomyositis: A randomized, double-blind, placebo-controlled crossover trial.

PubMed

Solis, Marina Yazigi; Hayashi, Ana Paula; Artioli, Guilherme Giannini; Roschel, Hamilton; Sapienza, Marcelo Tatit; Otaduy, Maria Concepción; De Sã Pinto, Ana Lucia; Silva, Clovis Artur; Sallum, Adriana Maluf Elias; Pereira, Rosa Maria R; Gualano, Bruno

2016-01-01

It has been suggested that creatine supplementation is safe and effective for treating idiopathic inflammatory myopathies, but no pediatric study has been conducted to date. The objective of this study was to examine the efficacy and safety of creatine supplementation in juvenile dermatomyositis (JDM) patients. In this study, JDM patients received placebo or creatine supplementation (0.1 g/kg/day) in a randomized, crossover, double-blind design. Subjects were assessed at baseline and after 12 weeks. The primary outcome was muscle function. Secondary outcomes included body composition, aerobic conditioning, health-related quality of life, and muscle phosphocreatine (PCr) content. Safety was assessed by laboratory parameters and kidney function measurements. Creatine supplementation did not affect muscle function, intramuscular PCr content, or any other secondary outcome. Kidney function was not affected, and no side effects were reported. Twelve weeks of creatine supplementation in JDM patients were well-tolerated and free of adverse effects, but treatment did not affect muscle function, intramuscular PCr, or any other parameter. © 2015 Wiley Periodicals, Inc.

Influence of heat and moisture exchanger respiratory load on transcutaneous oxygenation in laryngectomized individuals: a randomized crossover study.

PubMed

Zuur, J Karel; Muller, Sara H; Sinaasappel, Michiel; Hart, Guus A M; van Zandwijk, Nico; Hilgers, Frans J M

2007-12-01

High-resistance heat and moisture exchangers (HMEs) have been reported to increase transcutaneous oxygenation (tcpO(2)) values in laryngectomized individuals and to negatively influence patient compliance. The goal of the present study was to validate earlier published results on short-term transcutaneous oxygenation changes by high-resistance HMEs. We conducted a randomized crossover study, monitoring the influence of an HME on tcpO(2) over a 2-hour time interval in 20 subjects. No evidence of an immediate HME effect (95% CI: -14.9-13.3 mm Hg, p = .91), or a time-dependent HME effect (95% CI: -.121 - .172 mm Hg/minute, p = .74), on tcpO(2) was found. After fitting the statistical model without time dependency, again no evidence of HME presence was seen (95% CI: -.5 mm Hg - 3.6 mm Hg, p = .15). In contrast to earlier suggestions, there is no evidence of increased tcpO(2) levels by high-resistance HMEs in laryngectomized individuals. Thus, using such HMEs has no added clinical value in this respect.

Antiseptic Body Washes for Reducing the Transmission of Methicillin-Resistant Staphylococcus aureus: A Cluster Crossover Study.

PubMed

Harris, Patrick N A; Le, Bich Diep; Tambyah, Paul; Hsu, Li Yang; Pada, Surinder; Archuleta, Sophia; Salmon, Sharon; Mukhopadhyay, Amartya; Dillon, Jasmine; Ware, Robert; Fisher, Dale A

2015-04-01

Background.  Limiting the spread of methicillin-resistant Staphylococcus aureus (MRSA) within healthcare facilities where the organism is highly endemic is a challenge. The use of topical antiseptic agents may help interrupt the transmission of MRSA and reduce the risk of clinical infection. Octenidine dihydrochloride is a topical antiseptic that exhibits in vitro efficacy against a wide variety of bacteria, including S aureus. Methods.  We conducted a prospective cluster crossover study to compare the use of daily octenidine body washes with soap and water in patients identified by active surveillance cultures to be MRSA-colonized, to prevent the acquisition of MRSA in patients with negative screening swabs. Five adult medical and surgical wards and 2 intensive care units were selected. The study involved an initial 6-month phase using octenidine or soap washes followed by a crossover in each ward to the alternative product. The primary and secondary outcomes were the rates of new MRSA acquisitions and MRSA clinical infections, respectively. Results.  A total of 10 936 patients admitted for ≥48 hours was included in the analysis. There was a small reduction in MRSA acquisition in the intervention group compared with controls (3.0% vs 3.3%), but this reduction was not significant (odds ratio, 0.89; 95% confidence interval, .72-1.11; P = .31). There were also no significant differences in clinical MRSA infection or incidence of MRSA bacteremia. Conclusions.  This study suggests that the targeted use of routine antiseptic washes may not in itself be adequate to reduce the transmission of MRSA in an endemic hospital setting.

Size effects on the thermal conductivity of amorphous silicon thin films

DOE PAGES

Thomas Edwin Beechem; Braun, Jeffrey L.; Baker, Christopher H.; ...

2016-04-01

In this study, we investigate thickness-limited size effects on the thermal conductivity of amorphous silicon thin films ranging from 3 to 1636 nm grown via sputter deposition. While exhibiting a constant value up to ~100 nm, the thermal conductivity increases with film thickness thereafter. The thickness dependence we demonstrate is ascribed to boundary scattering of long wavelength vibrations and an interplay between the energy transfer associated with propagating modes (propagons) and nonpropagating modes (diffusons). A crossover from propagon to diffuson modes is deduced to occur at a frequency of ~1.8 THz via simple analytical arguments. These results provide empirical evidencemore » of size effects on the thermal conductivity of amorphous silicon and systematic experimental insight into the nature of vibrational thermal transport in amorphous solids.« less

Effect of Persian Medicine Remedy on Chemotherapy Induced Nausea and Vomiting in Breast Cancer: A Double Blind, Randomized, Crossover Clinical Trial

PubMed Central

Nazari, Mohammad; Taghizadeh, Ali; Bazzaz, Mojtaba Mousavi; Rakhshandeh, Hassan; Shokri, Sadegh

2017-01-01

Background Chemotherapy induced nausea and vomiting (CINV) is a side effect, and has negative effect on quality of life and continuation of chemotherapy. Despite new regimen and drugs, the problems still remain and standard guidelines, effective treatment and supportive care for refractory CINV are still not yet established. Persian medicine, the old Iranian medical school, offer Persumac (prepared from Rhus Coriaria and Bunium Persicum Boiss). Objective The specific objectives were to assess the effect of Persumac on the number and severity of nausea and vomiting in refractory CINV in acute and delayed phase. Methods This randomized, double blind, crossover clinical trial study was carried out on 93 patients with breast cancer and refractory CINV, who received outpatient high emetogenic chemotherapy in Imam Reza hospital, Mashhad, Iran from October 2015 to May 2016. The study has three stages: in stage I patients received a questionaire and completed it after chemotherapy. In stage II they were randomly divided into intervention group with Persumac and control group with placebo (lactose were used). In stage III, wash out and crossover was conducted. Both groups in all stages received standard antiemetic therapy for CINV. The following were set as the inclusion criteria of the study: female, Age ≥18 years, clinical diagnosis of breast cancer, history of refractory CINV, normal blood tests and at least three courses of chemotherapy remaining. Exclusion criteria of this study were: Total or upper abdominal radiation therapy along with chemotherapy, drugs/therapy for nausea and vomiting not prescribed in this study, hypersensitivity to Sumac or Bunium Persicum, use of sumac and Bunium Persicum in seven days prior to the intervention, clinical diagnosis of digestion disorders, non-chemotherapy induced nausea and vomiting, milk allergy, loss of two consecutive or three intermittent doses of Persumac or placebo. Outcomes were gathered by Persian questionnaire. Number and severity of nausea and vomiting was measured with a self-reporting tool; visual analog scale. Results Demographic data and other characters in both groups have no significant diffrence. Eighty of 93 eligible patients in stage I completed the study and in stage II, eleven declined participation for stage III (crossover). P value of carry over, period and treatment effects demonstrated that they had not affected the results before and after crossover. The mean severity of nausea in acute phase was in stage I: 4.83 ± 1.40, stage II: 4.54 ± 2.0 and stage III: 4.15 ± 0.92 in sequence AB (first Persumac and then placebo in crossover), and in sequence BA (first placebo and then Persumac in crossover) was respectively 4.83 ± 1.40, 4.54 ± 2.0, 4.15 ± 0.92 with p value of carry over effect: 0.03 and period effect: 0.22. Except for severity of nausea in acute phase, the mean number and severity of nausea and vomiting scores significantly decreased in acute and delayed phase of CINV. Conclusion Persumac may control the refractory CINV. The implicable and clinical importance of this research is that another option exists for refractory CINV. Higher doses, different cancers, patients with more various features, and more complete methodology and tools can provide appropriate designs for new research on this topic. Trial registration This trial was registered at the Clinical Trials.gov ID: NCT02787707. Funding This study is part of a Ph.D. thesis and under grant; No: 930735 of Research Chancellery of MUMS. PMID:28243404

On the equivalence of case-crossover and time series methods in environmental epidemiology.

PubMed

Lu, Yun; Zeger, Scott L

2007-04-01

The case-crossover design was introduced in epidemiology 15 years ago as a method for studying the effects of a risk factor on a health event using only cases. The idea is to compare a case's exposure immediately prior to or during the case-defining event with that same person's exposure at otherwise similar "reference" times. An alternative approach to the analysis of daily exposure and case-only data is time series analysis. Here, log-linear regression models express the expected total number of events on each day as a function of the exposure level and potential confounding variables. In time series analyses of air pollution, smooth functions of time and weather are the main confounders. Time series and case-crossover methods are often viewed as competing methods. In this paper, we show that case-crossover using conditional logistic regression is a special case of time series analysis when there is a common exposure such as in air pollution studies. This equivalence provides computational convenience for case-crossover analyses and a better understanding of time series models. Time series log-linear regression accounts for overdispersion of the Poisson variance, while case-crossover analyses typically do not. This equivalence also permits model checking for case-crossover data using standard log-linear model diagnostics.

Effects of Subsensory Noise and Fatigue on Knee Landing and Cross-over Cutting Biomechanics in Male Athletes.

PubMed

Qu, Xingda; Jiang, Jianxin; Hu, Xinyao

2018-06-01

The objective of this study was to examine the effects of subsensory noise and fatigue on knee biomechanics during the athletic task of landing followed by cross-over cutting. A total of 32 healthy male athletes participated in the study. They were evenly divided into 2 groups: no fatigue group and fatigue group. Fatigue was induced to the lower extremity by a repetitive squatting exercise in the fatigue group. Subsensory noise was generated by linear miniature vibrators bilaterally placed around the knee joints. During data collection, the participants were instructed to perform landing followed by cross-over cutting in both the subsensory on and off conditions. Dependent variables were selected to assess knee biomechanics in the phases of landing and cross-over cutting, separately. Results showed that fatigue resulted in larger knee flexion during landing and larger knee internal rotation during cross-over cutting. Subsensory noise was found to reduce knee rotation impulse during cross-over cutting. These findings suggest that cross-over cutting is more dangerous than landing in the fatigue condition, and subsensory noise may lead to changes in knee biomechanics consistent with reduced risk of anterior cruciate ligament injuries, but the changes may be task-specific.

Threshold Levels of Infant and Under-Five Mortality for Crossover between Life Expectancies at Ages Zero, One and Five in India: A Decomposition Analysis

PubMed Central

Dubey, Manisha

2015-01-01

Objectives Under the prevailing conditions of imbalanced life table and historic gender discrimination in India, our study examines crossover between life expectancies at ages zero, one and five years for India and quantifies the relative share of infant and under-five mortality towards this crossover. Methods We estimate threshold levels of infant and under-five mortality required for crossover using age specific death rates during 1981–2009 for 16 Indian states by sex (comprising of India’s 90% population in 2011). Kitagawa decomposition equations were used to analyse relative share of infant and under-five mortality towards crossover. Findings India experienced crossover between life expectancies at ages zero and five in 2004 for menand in 2009 for women; eleven and nine Indian states have experienced this crossover for men and women, respectively. Men usually experienced crossover four years earlier than the women. Improvements in mortality below ages five have mostly contributed towards this crossover. Life expectancy at age one exceeds that at age zero for both men and women in India except for Kerala (the only state to experience this crossover in 2000 for men and 1999 for women). Conclusions For India, using life expectancy at age zero and under-five mortality rate together may be more meaningful to measure overall health of its people until the crossover. Delayed crossover for women, despite higher life expectancy at birth than for men reiterates that Indian women are still disadvantaged and hence use of life expectancies at ages zero, one and five become important for India. Greater programmatic efforts to control leading causes of death during the first month and 1–59 months in high child mortality areas can help India to attain this crossover early. PMID:26683617

Incoherent-to-coherent crossover of optical spectra in La0.825Sr0.175MnO3: Temperature-dependent reflectivity spectra measured on cleaved surfaces

NASA Astrophysics Data System (ADS)

Takenaka, K.; Sawaki, Y.; Sugai, S.

1999-11-01

Optical reflectivity spectra were measured on cleaved surfaces of La0.825Sr0.175MnO3 single crystals (TC=283 K) over a temperature range 10-295 K. The optical conductivity σ(ω) shows incoherent-to-coherent crossover with decreasing temperature. The minimum metallic conductivity σmin of this compound was determined by the dc resistivity ρ(T) measurements of Al-substituted crystals (La0.825Sr0.175)(Mn1-zAlz)O3 and was found to be 2000-3000 Ω-1 cm-1. This indicates that the dc conductivity of La0.825Sr0.175MnO3 is smaller than σmin over a wide temperature range below TC even though ρ(T) is metallic (dρ/dT>0). The present results suggest that there are two types of the ferromagnetic-metallic phase below TC-a ``high-temperature incoherent'' metallic (HIM) and a ``low-temperature coherent'' metallic phase. ``Colossal magnetoresistance'' is a characteristic of the HIM phase.

Crossover behavior of the thermal conductance and Kramers’ transition rate theory

DOE PAGES

Velizhanin, Kirill A.; Sahu, Subin; Chien, Chih -Chun; ...

2015-12-04

Kramers’ theory frames chemical reaction rates in solution as reactants overcoming a barrier in the presence of friction and noise. For weak coupling to the solution, the reaction rate is limited by the rate at which the solution can restore equilibrium after a subset of reactants have surmounted the barrier to become products. For strong coupling, there are always sufficiently energetic reactants. However, the solution returns many of the intermediate states back to the reactants before the product fully forms. Here, we demonstrate that the thermal conductance displays an analogous physical response to the friction and noise that drive themore » heat current through a material or structure. A crossover behavior emerges where the thermal reservoirs dominate the conductance at the extremes and only in the intermediate region are the intrinsic properties of the lattice manifest. Finally, not only does this shed new light on Kramers’ classic turnover problem, this result is significant for the design of devices for thermal management and other applications, as well as the proper simulation of transport at the nanoscale.« less

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries

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

Doris, Sean E.; Ward, Ashleigh L.; Baskin, Artem

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. In this paper, we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the ratemore » of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm -2 day -1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. Finally, this strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries.« less

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries.

PubMed

Doris, Sean E; Ward, Ashleigh L; Baskin, Artem; Frischmann, Peter D; Gavvalapalli, Nagarjuna; Chénard, Etienne; Sevov, Christo S; Prendergast, David; Moore, Jeffrey S; Helms, Brett A

2017-02-01

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. Here we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the rate of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm -2  day -1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries

DOE PAGES

Doris, Sean E.; Ward, Ashleigh L.; Baskin, Artem; ...

2017-01-10

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. In this paper, we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the ratemore » of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm -2 day -1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. Finally, this strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries.« less

High-Performance Oligomeric Catholytes for Effective Macromolecular Separation in Nonaqueous Redox Flow Batteries

PubMed Central

2018-01-01

Nonaqueous redox flow batteries (NRFBs) represent an attractive technology for energy storage from intermittent renewable sources. In these batteries, electrical energy is stored in and extracted from electrolyte solutions of redox-active molecules (termed catholytes and anolytes) that are passed through an electrochemical flow cell. To avoid battery self-discharge, the anolyte and catholyte solutions must be separated by a membrane in the flow cell. This membrane prevents crossover of the redox active molecules, while simultaneously allowing facile transport of charge-balancing ions. A key unmet challenge for the field is the design of redox-active molecule/membrane pairs that enable effective electrolyte separation while maintaining optimal battery properties. Herein, we demonstrate the development of oligomeric catholytes based on tris(dialkylamino)cyclopropenium (CP) salts that are specifically tailored for pairing with size-exclusion membranes composed of polymers of intrinsic microporosity (PIMs). Systematic studies were conducted to evaluate the impact of oligomer size/structure on properties that are crucial for flow battery performance, including cycling stability, charge capacity, solubility, electron transfer kinetics, and crossover rates. These studies have led to the identification of a CP-derived tetramer in which these properties are all comparable, or significantly improved, relative to the monomeric counterpart. Finally, a proof-of-concept flow battery is demonstrated by pairing this tetrameric catholyte with a PIM membrane. After 6 days of cycling, no crossover is detected, demonstrating the promise of this approach. These studies provide a template for the future design of other redox-active oligomers for this application. PMID:29532018

High-Performance Oligomeric Catholytes for Effective Macromolecular Separation in Nonaqueous Redox Flow Batteries

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

Hendriks, Koen H.; Robinson, Sophia G.; Braten, Miles N.

Nonaqueous redox flow batteries (NRFBs) represent an attractive technology for energy storage from intermittent renewable sources. In these batteries, electrical energy is stored in and extracted from electrolyte solutions of redox-active molecules (termed catholytes and anolytes) that are passed through an electrochemical flow cell. To avoid battery self-discharge, the anolyte and catholyte solutions must be separated by a membrane in the flow cell. This membrane prevents crossover of the redox active molecules, while simultaneously allowing facile transport of charge-balancing ions. A key unmet challenge for the field is the design of redox-active molecule/membrane pairs that enable effective electrolyte separation whilemore » maintaining optimal battery properties. Herein, we demonstrate the development of oligomeric catholytes based on tris(dialkylamino)cyclopropenium (CP) salts that are specifically tailored for pairing with size-exclusion membranes composed of polymers of intrinsic microporosity (PIMs). Systematic studies were conducted to evaluate the impact of oligomer size/structure on properties that are crucial for flow battery performance, including cycling stability, charge capacity, solubility, electron transfer kinetics, and crossover rates. These studies have led to the identification of a CP-derived tetramer in which these properties are all comparable, or significantly improved, relative to the monomeric counterpart. Finally, a proof-of-concept flow battery is demonstrated by pairing this tetrameric catholyte with a PIM membrane. After 6 days of cycling, no crossover is detected, demonstrating the promise of this approach. Finally, these studies provide a template for the future design of other redox-active oligomers for this application.« less

High-Performance Oligomeric Catholytes for Effective Macromolecular Separation in Nonaqueous Redox Flow Batteries.

PubMed

Hendriks, Koen H; Robinson, Sophia G; Braten, Miles N; Sevov, Christo S; Helms, Brett A; Sigman, Matthew S; Minteer, Shelley D; Sanford, Melanie S

2018-02-28

Nonaqueous redox flow batteries (NRFBs) represent an attractive technology for energy storage from intermittent renewable sources. In these batteries, electrical energy is stored in and extracted from electrolyte solutions of redox-active molecules (termed catholytes and anolytes) that are passed through an electrochemical flow cell. To avoid battery self-discharge, the anolyte and catholyte solutions must be separated by a membrane in the flow cell. This membrane prevents crossover of the redox active molecules, while simultaneously allowing facile transport of charge-balancing ions. A key unmet challenge for the field is the design of redox-active molecule/membrane pairs that enable effective electrolyte separation while maintaining optimal battery properties. Herein, we demonstrate the development of oligomeric catholytes based on tris(dialkylamino)cyclopropenium (CP) salts that are specifically tailored for pairing with size-exclusion membranes composed of polymers of intrinsic microporosity (PIMs). Systematic studies were conducted to evaluate the impact of oligomer size/structure on properties that are crucial for flow battery performance, including cycling stability, charge capacity, solubility, electron transfer kinetics, and crossover rates. These studies have led to the identification of a CP-derived tetramer in which these properties are all comparable, or significantly improved, relative to the monomeric counterpart. Finally, a proof-of-concept flow battery is demonstrated by pairing this tetrameric catholyte with a PIM membrane. After 6 days of cycling, no crossover is detected, demonstrating the promise of this approach. These studies provide a template for the future design of other redox-active oligomers for this application.

High-Performance Oligomeric Catholytes for Effective Macromolecular Separation in Nonaqueous Redox Flow Batteries

DOE PAGES

Hendriks, Koen H.; Robinson, Sophia G.; Braten, Miles N.; ...

2018-01-17

Nonaqueous redox flow batteries (NRFBs) represent an attractive technology for energy storage from intermittent renewable sources. In these batteries, electrical energy is stored in and extracted from electrolyte solutions of redox-active molecules (termed catholytes and anolytes) that are passed through an electrochemical flow cell. To avoid battery self-discharge, the anolyte and catholyte solutions must be separated by a membrane in the flow cell. This membrane prevents crossover of the redox active molecules, while simultaneously allowing facile transport of charge-balancing ions. A key unmet challenge for the field is the design of redox-active molecule/membrane pairs that enable effective electrolyte separation whilemore » maintaining optimal battery properties. Herein, we demonstrate the development of oligomeric catholytes based on tris(dialkylamino)cyclopropenium (CP) salts that are specifically tailored for pairing with size-exclusion membranes composed of polymers of intrinsic microporosity (PIMs). Systematic studies were conducted to evaluate the impact of oligomer size/structure on properties that are crucial for flow battery performance, including cycling stability, charge capacity, solubility, electron transfer kinetics, and crossover rates. These studies have led to the identification of a CP-derived tetramer in which these properties are all comparable, or significantly improved, relative to the monomeric counterpart. Finally, a proof-of-concept flow battery is demonstrated by pairing this tetrameric catholyte with a PIM membrane. After 6 days of cycling, no crossover is detected, demonstrating the promise of this approach. Finally, these studies provide a template for the future design of other redox-active oligomers for this application.« less

Cannabis for dyskinesia in Parkinson disease: a randomized double-blind crossover study.

PubMed

Carroll, C B; Bain, P G; Teare, L; Liu, X; Joint, C; Wroath, C; Parkin, S G; Fox, P; Wright, D; Hobart, J; Zajicek, J P

2004-10-12

The long-term treatment of Parkinson disease (PD) may be complicated by the development of levodopa-induced dyskinesia. Clinical and animal model data support the view that modulation of cannabinoid function may exert an antidyskinetic effect. The authors conducted a randomized, double-blind, placebo-controlled crossover trial to examine the hypothesis that cannabis may have a beneficial effect on dyskinesia in PD. A 4-week dose escalation study was performed to assess the safety and tolerability of cannabis in six PD patients with levodopa-induced dyskinesia. Then a randomized placebo-controlled crossover study (RCT) was performed, in which 19 PD patients were randomized to receive oral cannabis extract followed by placebo or vice versa. Each treatment phase lasted for 4 weeks with an intervening 2-week washout phase. The primary outcome measure was a change in Unified Parkinson's Disease Rating Scale (UPDRS) (items 32 to 34) dyskinesia score. Secondary outcome measures included the Rush scale, Bain scale, tablet arm drawing task, and total UPDRS score following a levodopa challenge, as well as patient-completed measures of a dyskinesia activities of daily living (ADL) scale, the PDQ-39, on-off diaries, and a range of category rating scales. Seventeen patients completed the RCT. Cannabis was well tolerated, and had no pro- or antiparkinsonian action. There was no evidence for a treatment effect on levodopa-induced dyskinesia as assessed by the UPDRS, or any of the secondary outcome measures. Orally administered cannabis extract resulted in no objective or subjective improvement in dyskinesias or parkinsonism.

Case-Crossover Analysis of Air Pollution Health Effects: A Systematic Review of Methodology and Application

PubMed Central

Carracedo-Martínez, Eduardo; Taracido, Margarita; Tobias, Aurelio; Saez, Marc; Figueiras, Adolfo

2010-01-01

Background Case-crossover is one of the most used designs for analyzing the health-related effects of air pollution. Nevertheless, no one has reviewed its application and methodology in this context. Objective We conducted a systematic review of case-crossover (CCO) designs used to study the relationship between air pollution and morbidity and mortality, from the standpoint of methodology and application. Data sources and extraction A search was made of the MEDLINE and EMBASE databases. Reports were classified as methodologic or applied. From the latter, the following information was extracted: author, study location, year, type of population (general or patients), dependent variable(s), independent variable(s), type of CCO design, and whether effect modification was analyzed for variables at the individual level. Data synthesis The review covered 105 reports that fulfilled the inclusion criteria. Of these, 24 addressed methodological aspects, and the remainder involved the design’s application. In the methodological reports, the designs that yielded the best results in simulation were symmetric bidirectional CCO and time-stratified CCO. Furthermore, we observed an increase across time in the use of certain CCO designs, mainly symmetric bidirectional and time-stratified CCO. The dependent variables most frequently analyzed were those relating to hospital morbidity; the pollutants most often studied were those linked to particulate matter. Among the CCO-application reports, 13.6% studied effect modification for variables at the individual level. Conclusions The use of CCO designs has undergone considerable growth; the most widely used designs were those that yielded better results in simulation studies: symmetric bidirectional and time-stratified CCO. However, the advantages of CCO as a method of analysis of variables at the individual level are put to little use. PMID:20356818

Spillover and Crossover of Exhaustion and Life Satisfaction among Dual-Earner Parents

ERIC Educational Resources Information Center

Demerouti, Evangelia; Bakker, Arnold B.; Schaufeli, Wilmar B.

2005-01-01

This study integrates spillover research of stress transferring from work to home and crossover research of strains transferring from one spouse to another. A spillover and crossover model was tested among 191 (couples of) dual-earner parents. For both males and females, it was hypothesized that (self-reported and partners' rating of)…

A Randomized, Placebo-Controlled, Crossover Trial of Cannabis Cigarettes in Neuropathic Pain

PubMed Central

Wilsey, Barth; Marcotte, Thomas; Tsodikov, Alexander; Millman, Jeanna; Bentley, Heather; Gouaux, Ben; Fishman, Scott

2016-01-01

The Food and Drug Administration (FDA), Substance Abuse and Mental Health Services Administration (SAMHSA), and the National Institute for Drug Abuse (NIDA) report that no sound scientific studies support the medicinal use of cannabis. Despite this lack of scientific validation, many patients routinely use “medical marijuana,” and in many cases this use is for pain related to nerve injury. We conducted a double-blinded, placebo-controlled, crossover study evaluating the analgesic efficacy of smoking cannabis for neuropathic pain. Thirty-eight patients with central and peripheral neuropathic pain underwent a standardized procedure for smoking either high-dose (7%), low-dose (3.5%), or placebo cannabis. In addition to the primary outcome of pain intensity, secondary outcome measures included evoked pain using heat-pain threshold, sensitivity to light touch, psychoactive side effects, and neuropsychological performance. A mixed linear model demonstrated an analgesic response to smoking cannabis. No effect on evoked pain was seen. Psychoactive effects were minimal and well-tolerated, with some acute cognitive effects, particularly with memory, at higher doses. PMID:18403272

Using sit-stand workstations to decrease sedentary time in office workers: a randomized crossover trial.

PubMed

Dutta, Nirjhar; Koepp, Gabriel A; Stovitz, Steven D; Levine, James A; Pereira, Mark A

2014-06-25

This study was conducted to determine whether installation of sit-stand desks (SSDs) could lead to decreased sitting time during the workday among sedentary office workers. A randomized cross-over trial was conducted from January to April, 2012 at a business in Minneapolis. 28 (nine men, 26 full-time) sedentary office workers took part in a 4 week intervention period which included the use of SSDs to gradually replace 50% of sitting time with standing during the workday. Physical activity was the primary outcome. Mood, energy level, fatigue, appetite, dietary intake, and productivity were explored as secondary outcomes. The intervention reduced sitting time at work by 21% (95% CI 18%-25%) and sedentary time by 4.8 min/work-hr (95% CI 4.1-5.4 min/work-hr). For a 40 h work-week, this translates into replacement of 8 h of sitting time with standing and sedentary time being reduced by 3.2 h. Activity level during non-work hours did not change. The intervention also increased overall sense of well-being, energy, decreased fatigue, had no impact on productivity, and reduced appetite and dietary intake. The workstations were popular with the participants. The SSD intervention was successful in increasing work-time activity level, without changing activity level during non-work hours.

Bayesian analysis of time-series data under case-crossover designs: posterior equivalence and inference.

PubMed

Li, Shi; Mukherjee, Bhramar; Batterman, Stuart; Ghosh, Malay

2013-12-01

Case-crossover designs are widely used to study short-term exposure effects on the risk of acute adverse health events. While the frequentist literature on this topic is vast, there is no Bayesian work in this general area. The contribution of this paper is twofold. First, the paper establishes Bayesian equivalence results that require characterization of the set of priors under which the posterior distributions of the risk ratio parameters based on a case-crossover and time-series analysis are identical. Second, the paper studies inferential issues under case-crossover designs in a Bayesian framework. Traditionally, a conditional logistic regression is used for inference on risk-ratio parameters in case-crossover studies. We consider instead a more general full likelihood-based approach which makes less restrictive assumptions on the risk functions. Formulation of a full likelihood leads to growth in the number of parameters proportional to the sample size. We propose a semi-parametric Bayesian approach using a Dirichlet process prior to handle the random nuisance parameters that appear in a full likelihood formulation. We carry out a simulation study to compare the Bayesian methods based on full and conditional likelihood with the standard frequentist approaches for case-crossover and time-series analysis. The proposed methods are illustrated through the Detroit Asthma Morbidity, Air Quality and Traffic study, which examines the association between acute asthma risk and ambient air pollutant concentrations. © 2013, The International Biometric Society.

Short-term effects of particulate matter on total mortality during Saharan dust outbreaks: a case-crossover analysis in Madrid (Spain).

PubMed

Tobías, Aurelio; Pérez, Laura; Díaz, Julio; Linares, Cristina; Pey, Jorge; Alastruey, Andrés; Querol, Xavier

2011-12-15

The role of Saharan dust outbreaks on the relationship between particulate matter and daily mortality has recently been addressed in studies conducted in Southern Europe, although they have not given consistent results. We investigated the effects of coarse (PM(10-2.5)) and fine particulate matter (PM(2.5)) in Madrid on total mortality during Saharan dust and non-dust days using a case-crossover design. During Saharan dust days, an increase of 10mg/m(3) of PM(10-2.5) raised total mortality by 2.8% compared with 0.6% during non-dust days (P-value for interaction=0.0165). We found evidence of stronger adverse health effects of PM(10-2.5) during Saharan dust outbreaks effects for impacted European populations, but not for PM(2.5). Further research is needed to understand mechanisms by which Saharan dust increases risk of mortality. Copyright © 2011 Elsevier B.V. All rights reserved.

Lactobacillus salivarius WB21--containing tablets for the treatment of oral malodor: a double-blind, randomized, placebo-controlled crossover trial.

PubMed

Suzuki, Nao; Yoneda, Masahiro; Tanabe, Kazunari; Fujimoto, Akie; Iha, Kosaku; Seno, Kei; Yamada, Kazuhiko; Iwamoto, Tomoyuki; Masuo, Yosuke; Hirofuji, Takao

2014-04-01

This study evaluated the effect of probiotic intervention using lactobacilli on oral malodor. We conducted a 14-day, double-blind, placebo-controlled, randomized crossover trial of tablets containing Lactobacillus salivarius WB21 (2.0 × 10(9) colony-forming units per day) or placebo taken orally by patients with oral malodor. Organoleptic test scores significantly decreased in both the probiotic and placebo periods compared with the respective baseline scores (P < .001 and P = .002), and no difference was detected between periods. In contrast, the concentration of volatile sulfur compounds (VSCs) (P = .019) and the average probing pocket depth (P = .001) decreased significantly in the probiotic period compared with the placebo period. Bacterial quantitative analysis found significantly lower levels of ubiquitous bacteria (P = .003) and Fusobacterium nucleatum (P = .020) in the probiotic period. These results indicated that daily oral consumption of tablets containing probiotic lactobacilli could help to control oral malodor and malodor-related factors. Copyright © 2014 Elsevier Inc. All rights reserved.

Prescription of Zolpidem and the Risk of Fatal Motor Vehicle Collisions: A Population-Based, Case-Crossover Study from South Korea.

PubMed

Yang, Bo Ram; Kim, Ye-Jee; Kim, Mi-Sook; Jung, Sun-Young; Choi, Nam-Kyong; Hwang, Byungkwan; Park, Byung-Joo; Lee, Joongyub

2018-05-23

Zolpidem is one of the most frequently used hypnotics worldwide, but associations with serious adverse effects such as motor vehicle collisions have been reported. The objective of this study was to evaluate the association of fatal motor vehicle collisions with a prescription for zolpidem, considering the context of the motor vehicle collisions. We conducted a case-crossover study, where each case served as its own control, by linking data about fatal motor vehicle collisions from the Korean Road Traffic Authority between 2010 and 2014 with national health insurance data. The case period was defined as 1 day before the fatal motor vehicle collisions, and was matched to four control periods at 90-day intervals. Conditional logistic regression was performed to calculate the odds ratio for fatal motor vehicle collisions associated with zolpidem exposure, and odds ratios were adjusted for time-varying exposure to confounding medications. A stratified analysis was performed by age group (younger than 65 years or not), the Charlson Comorbidity Index, and whether patients were new zolpidem users. Among the 714 subjects, the adjusted odds ratio for a fatal motor vehicle collision associated with a prescription for zolpidem the previous day was 1.48 (95% confidence interval 1.06-2.07). After stratification, a significantly increased risk was observed in subjects with a high Charlson Comorbidity Index (odds ratio 1.81; 95% confidence interval 1.16-2.84), the younger age group (odds ratio: 1.62; 95% confidence interval 1.03-2.56), and new zolpidem users (odds ratio 2.37; 95% confidence interval 1.40-4.00). A prescription for zolpidem on the previous day was significantly related to an increased risk of fatal motor vehicle collisions in this population-based case-crossover study.

A case-crossover study on transient risk factors of work-related eye injuries.

PubMed

Chen, S-Y; Fong, P-C; Lin, S-F; Chang, C-H; Chan, C-C

2009-08-01

To investigate modifiable risk and preventive factors of work-related eye injuries. A case-crossover study conducted to explore the associations between transient risk factors and work-related eye injuries. Patients seen at seven medical centres in Taiwan with work-related eye injuries over a 4-year period were enrolled in the study. Clinical information was collected from medical charts and detailed information on exposure to eight potentially modifiable factors during the 60 minutes prior to the occurrence of each injury, as well as during the same time interval on the last work day prior to the injury, were obtained using questionnaire surveys. Matched-pair interval analysis was adopted to assess the odds ratios (ORs) for work-related eye injuries given exposure to the eight modifiable factors. A total of 283 subjects were interviewed. Most of these injured workers were young, male, and self-employed or small enterprise workers. The most common injury type was photokeratitis (33.2%), mainly caused by welding (30.4%). The OR for a work-related eye injury was increased with the performance of an unfamiliar task (57.0), operation of a faulty tool or piece of equipment (48.5), distractions (24.0), being rushed (13.0), or fatigued (10.0), and a poor work environment (4.3). Wearing eye protection devices was found to have a significant protective effect on workers who might otherwise have been exposed to eye injuries (OR = 0.4; 95% CI 0.2 to 0.7). Potential modifiable risk and preventive factors for work-related eye injuries were identified using a case-crossover study. This information should be helpful in the development of preventive strategies.

Antiseptic Body Washes for Reducing the Transmission of Methicillin-Resistant Staphylococcus aureus: A Cluster Crossover Study

PubMed Central

Harris, Patrick N. A.; Le, Bich Diep; Tambyah, Paul; Hsu, Li Yang; Pada, Surinder; Archuleta, Sophia; Salmon, Sharon; Mukhopadhyay, Amartya; Dillon, Jasmine; Ware, Robert; Fisher, Dale A.

2015-01-01

Background. Limiting the spread of methicillin-resistant Staphylococcus aureus (MRSA) within healthcare facilities where the organism is highly endemic is a challenge. The use of topical antiseptic agents may help interrupt the transmission of MRSA and reduce the risk of clinical infection. Octenidine dihydrochloride is a topical antiseptic that exhibits in vitro efficacy against a wide variety of bacteria, including S aureus. Methods. We conducted a prospective cluster crossover study to compare the use of daily octenidine body washes with soap and water in patients identified by active surveillance cultures to be MRSA-colonized, to prevent the acquisition of MRSA in patients with negative screening swabs. Five adult medical and surgical wards and 2 intensive care units were selected. The study involved an initial 6-month phase using octenidine or soap washes followed by a crossover in each ward to the alternative product. The primary and secondary outcomes were the rates of new MRSA acquisitions and MRSA clinical infections, respectively. Results. A total of 10 936 patients admitted for ≥48 hours was included in the analysis. There was a small reduction in MRSA acquisition in the intervention group compared with controls (3.0% vs 3.3%), but this reduction was not significant (odds ratio, 0.89; 95% confidence interval, .72–1.11; P = .31). There were also no significant differences in clinical MRSA infection or incidence of MRSA bacteremia. Conclusions. This study suggests that the targeted use of routine antiseptic washes may not in itself be adequate to reduce the transmission of MRSA in an endemic hospital setting. PMID:26125031

NON-HOMOGENEOUS POISSON PROCESS MODEL FOR GENETIC CROSSOVER INTERFERENCE.

PubMed

Leu, Szu-Yun; Sen, Pranab K

2014-01-01

The genetic crossover interference is usually modeled with a stationary renewal process to construct the genetic map. We propose two non-homogeneous, also dependent, Poisson process models applied to the known physical map. The crossover process is assumed to start from an origin and to occur sequentially along the chromosome. The increment rate depends on the position of the markers and the number of crossover events occurring between the origin and the markers. We show how to obtain parameter estimates for the process and use simulation studies and real Drosophila data to examine the performance of the proposed models.

Fingerprints of transverse and longitudinal coupling between induced open quantum dots in the longitudinal magnetoconductance through antidot lattices

NASA Astrophysics Data System (ADS)

Ujevic, Sebastian; Mendoza, Michel

2010-07-01

We propose numerical simulations of longitudinal magnetoconductance through a finite antidot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magnetoconductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magnetoconductance maps with crossovers (between transversal bands) and closings (longitudinal decoupling) of fundamental quantum states related to the open quantum dots induced by the antidot lattice. A relationship is observed between the distribution of antidots and the formed conductance bands, allowing a systematic follow up of the bands as a function of the applied magnetic field and quantum point-contact width. We observed a high conductance intensity [between n and (n+1) quantum of conductance, n=1,2,… ] in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the antidots potential and the quantum point-contact width. A new continuous channel (not expected) is induced by the variation in the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field.

Using oral polio vaccine beyond the cold chain: a feasibility study conducted during the national immunization campaign in Mali.

PubMed

Halm, Ariane; Yalcouyé, Idrissa; Kamissoko, Mady; Keïta, Tenemakan; Modjirom, Ndoutabé; Zipursky, Simona; Kartoglu, Umit; Ronveaux, Olivier

2010-04-26

We conducted the first systematic documentation of using oral polio vaccine (OPV) out of the cold chain during national immunization day (NID) campaigns in Mali. Using a crossover intervention design, vaccinators compared the transport of OPV in vaccine carriers with or without ice packs. Vaccine integrity was assured through monitoring vaccine vial monitor (VVM) status. Despite ambient temperatures up to 40 degrees C, none of the VVMs on any of the vials used (n=956) reached their discard point. Over 90% of vaccinators and supervisors preferred conducting NIDs without ice packs. In addition, using OPV out of the cold chain reduced vaccine wastage resulting from melting ice packs causing labels to detach from the vial. Copyright 2010 Elsevier Ltd. All rights reserved.

Quasiparticle Excitations in the Superconducting State of FeSe Probed by Thermal Hall Conductivity in the Vicinity of the BCS-BEC Crossover

NASA Astrophysics Data System (ADS)

Watashige, Tatsuya; Arsenijević, Stevan; Yamashita, Takuya; Terazawa, Daiki; Onishi, Takafumi; Opherden, Lars; Kasahara, Shigeru; Tokiwa, Yoshifumi; Kasahara, Yuichi; Shibauchi, Takasada; von Löhneysen, Hilbert; Wosnitza, Jochen; Matsuda, Yuji

2017-01-01

There is growing evidence that the superconducting semimetal FeSe (Tc ˜ 8 K) is in the crossover regime between weak-coupling Bardeen-Cooper-Schrieffer (BCS) and strong-coupling Bose-Einstein-condensate (BEC) limits. We report on longitudinal and transverse thermal conductivities, κxx and κxy, respectively, in magnetic fields up to 20 T. The field dependences of κxx and κxy imply that a highly anisotropic small superconducting gap forms at the electron Fermi-surface pocket whereas a more isotropic and larger gap forms at the hole pocket. Below ˜1.0 K, both κxx and κxy exhibit distinct anomalies (kinks) at the upper critical field Hc2 and at a field H* slightly below Hc2. The analysis of the thermal Hall angle (κxy/κxx) indicates a change of the quasiparticle scattering rate at H*. These results provide strong support to the previous suggestion that above H* a distinct field-induced superconducting phase emerges with an unprecedented large spin imbalance.

The short-term effects of air pollutants on respiratory disease mortality in Wuhan, China: comparison of time-series and case-crossover analyses

PubMed Central

Ren, Meng; Li, Na; Wang, Zhan; Liu, Yisi; Chen, Xi; Chu, Yuanyuan; Li, Xiangyu; Zhu, Zhongmin; Tian, Liqiao; Xiang, Hao

2017-01-01

Few studies have compared different methods when exploring the short-term effects of air pollutants on respiratory disease mortality in Wuhan, China. This study assesses the association between air pollutants and respiratory disease mortality with both time-series and time-stratified–case-crossover designs. The generalized additive model (GAM) and the conditional logistic regression model were used to assess the short-term effects of air pollutants on respiratory disease mortality. Stratified analyses were performed by age, sex, and diseases. A 10 μg/m3 increment in SO2 level was associated with an increase in relative risk for all respiratory disease mortality of 2.4% and 1.9% in the case-crossover and time-series analyses in single pollutant models, respectively. Strong evidence of an association between NO2 and daily respiratory disease mortality among men or people older than 65 years was found in the case-crossover study. There was a positive association between air pollutants and respiratory disease mortality in Wuhan, China. Both time-series and case-crossover analyses consistently reveal the association between three air pollutants and respiratory disease mortality. The estimates of association between air pollution and respiratory disease mortality from the case–crossover analysis displayed greater variation than that from the time-series analysis. PMID:28084399

The short-term effects of air pollutants on respiratory disease mortality in Wuhan, China: comparison of time-series and case-crossover analyses.

PubMed

Ren, Meng; Li, Na; Wang, Zhan; Liu, Yisi; Chen, Xi; Chu, Yuanyuan; Li, Xiangyu; Zhu, Zhongmin; Tian, Liqiao; Xiang, Hao

2017-01-13

Few studies have compared different methods when exploring the short-term effects of air pollutants on respiratory disease mortality in Wuhan, China. This study assesses the association between air pollutants and respiratory disease mortality with both time-series and time-stratified-case-crossover designs. The generalized additive model (GAM) and the conditional logistic regression model were used to assess the short-term effects of air pollutants on respiratory disease mortality. Stratified analyses were performed by age, sex, and diseases. A 10 μg/m 3 increment in SO 2 level was associated with an increase in relative risk for all respiratory disease mortality of 2.4% and 1.9% in the case-crossover and time-series analyses in single pollutant models, respectively. Strong evidence of an association between NO 2 and daily respiratory disease mortality among men or people older than 65 years was found in the case-crossover study. There was a positive association between air pollutants and respiratory disease mortality in Wuhan, China. Both time-series and case-crossover analyses consistently reveal the association between three air pollutants and respiratory disease mortality. The estimates of association between air pollution and respiratory disease mortality from the case-crossover analysis displayed greater variation than that from the time-series analysis.

The short-term effects of air pollutants on respiratory disease mortality in Wuhan, China: comparison of time-series and case-crossover analyses

NASA Astrophysics Data System (ADS)

Ren, Meng; Li, Na; Wang, Zhan; Liu, Yisi; Chen, Xi; Chu, Yuanyuan; Li, Xiangyu; Zhu, Zhongmin; Tian, Liqiao; Xiang, Hao

2017-01-01

Few studies have compared different methods when exploring the short-term effects of air pollutants on respiratory disease mortality in Wuhan, China. This study assesses the association between air pollutants and respiratory disease mortality with both time-series and time-stratified-case-crossover designs. The generalized additive model (GAM) and the conditional logistic regression model were used to assess the short-term effects of air pollutants on respiratory disease mortality. Stratified analyses were performed by age, sex, and diseases. A 10 μg/m3 increment in SO2 level was associated with an increase in relative risk for all respiratory disease mortality of 2.4% and 1.9% in the case-crossover and time-series analyses in single pollutant models, respectively. Strong evidence of an association between NO2 and daily respiratory disease mortality among men or people older than 65 years was found in the case-crossover study. There was a positive association between air pollutants and respiratory disease mortality in Wuhan, China. Both time-series and case-crossover analyses consistently reveal the association between three air pollutants and respiratory disease mortality. The estimates of association between air pollution and respiratory disease mortality from the case-crossover analysis displayed greater variation than that from the time-series analysis.

Small cause - big effect: improvement in interface design results in improved data quality - a multicenter crossover study.

PubMed

Ahlbrandt, Janko; Henrich, Michael; Hartmann, Bernd A; Bundschuh, Bettina B; Schwarz, Julia; Klasen, Joachim; Röhrig, Rainer

2012-01-01

In Germany the core data set for anesthesia version 3.0 was recently introduced for external quality assurance, which includes five surgical tracer procedures. We found a low rate of correctly documented tracers when compared to procedure data (OPS-Codes) documented separately. Examination revealed that the graphical user interface (GUI) contravened the dialogue principles as defined in EN ISO 9241-110. We worked with the manufacturer to implement small improvements and roll out the software. A crossover study was conducted at a university hospital and a municipal hospital chain with five hospitals. All study sites and surgical tracer procedures combined, we found an improvement from 42% to 65% (p<0.001; N=34,610) correctly documented anesthesias. We also saw improvements for most of the observed surgical tracer procedures at all hospitals. Our results show the big effect small changes to the GUI can have on data quality. They also raise the question, if highly flexible and parameterized clinical documentation systems are suited to achieve high usability. Finding the right balance between GUIs designed by usability experts and the flexibility of parameterization by administrators will be a difficult task for the future and subject to further research.

Methylene blue treatment for residual symptoms of bipolar disorder: randomised crossover study.

PubMed

Alda, Martin; McKinnon, Margaret; Blagdon, Ryan; Garnham, Julie; MacLellan, Susan; O'Donovan, Claire; Hajek, Tomas; Nair, Cynthia; Dursun, Serdar; MacQueen, Glenda

2017-01-01

Residual symptoms and cognitive impairment are among important sources of disability in patients with bipolar disorder. Methylene blue could improve such symptoms because of its potential neuroprotective effects. We conducted a double-blind crossover study of a low dose (15 mg, 'placebo') and an active dose (195 mg) of methylene blue in patients with bipolar disorder treated with lamotrigine. Thirty-seven participants were enrolled in a 6-month trial (trial registration: NCT00214877). The outcome measures included severity of depression, mania and anxiety, and cognitive functioning. The active dose of methylene blue significantly improved symptoms of depression both on the Montgomery-Åsberg Depression Rating Scale and Hamilton Rating Scale for Depression (P = 0.02 and 0.05 in last-observation-carried-forward analysis). It also reduced the symptoms of anxiety measured by the Hamilton Rating Scale for Anxiety (P = 0.02). The symptoms of mania remained low and stable throughout the study. The effects of methylene blue on cognitive symptoms were not significant. The medication was well tolerated with transient and mild side-effects. Methylene blue used as an adjunctive medication improved residual symptoms of depression and anxiety in patients with bipolar disorder. © The Royal College of Psychiatrists 2017.

Effects of Cationic Pendant Groups on Ionic Conductivity for Anion Exchange Membranes: Structure Conductivity Relationships

NASA Astrophysics Data System (ADS)

Kim, Sojeong; Choi, Soo-Hyung; Lee, Won Bo

Anion exchange membranes(AEMs) have been widely studied due to their various applications, especially for Fuel cells. Previous proton exchange membranes(PEMs), such as Nafions® have better conductivity than AEMs so far. However, technical limitations such as slow electrode kinetics, carbon monoxide (CO) poisoning of metal catalysts, high methanol crossover and high cost of Pt-based catalyst detered further usages. AEMs have advantages to supplement its drawbacks. AEMs are environmentally friendly and cost-efficient. Based on the well-defined block copolymer, self-assembled morphology is expected to have some relationship with its ionic conductivity. Recently AEMs based on various cations, including ammonium, phosphonium, guanidinium, imidazolium, metal cation, and benzimidazolium cations have been developed and extensively studied with the aim to prepare high- performance AEMs. But more fundamental approach, such as relationships between nanostructure and conductivity is needed. We use well-defined block copolymer Poly(styrene-block-isoprene) as a backbone which is synthesized by anionic polymerization. Then we graft various cationic functional groups and analysis the relation between morphology and conductivity. Theoretical and computational soft matter lab.

Are Emotions Transmitted From Work to Family? A Crossover Model of Psychological Contract Breach.

PubMed

Liang, Huai-Liang

2018-01-01

Based on affective events theory and the crossover model, this study examines the effect of psychological contract breach on employee dysfunctional behavior and partner family undermining and explores the crossover effect of employee dysfunctional behavior on partner family undermining in work-family issues. This study collected 370 employee-partner dyads (277 male employees, 93 female employees, M age = 43.59 years) from a large manufacturing organization. The results of this study support the conception that employees' psychological contract breach results in frustration in the workplace. In addition, mediation analysis results reveal that psychological contract breach relates to employee dysfunctional behavior in the workplace. The findings show that partners' psychological strain mediates the relationship between employee dysfunctional behavior and partner family undermining. Furthermore, these findings provide investigations for the crossover model to display the value of psychological contract breach in family issues.

Enhanced Proton Conductivity and Methanol Permeability Reduction via Sodium Alginate Electrolyte-Sulfonated Graphene Oxide Bio-membrane

NASA Astrophysics Data System (ADS)

Shaari, N.; Kamarudin, S. K.; Basri, S.; Shyuan, L. K.; Masdar, M. S.; Nordin, D.

2018-03-01

The high methanol crossover and high cost of Nafion® membrane are the major challenges for direct methanol fuel cell application. With the aim of solving these problems, a non-Nafion polymer electrolyte membrane with low methanol permeability and high proton conductivity based on the sodium alginate (SA) polymer as the matrix and sulfonated graphene oxide (SGO) as an inorganic filler (0.02-0.2 wt%) was prepared by a simple solution casting technique. The strong electrostatic attraction between -SO3H of SGO and the sodium alginate polymer increased the mechanical stability, optimized the water absorption and thus inhibited the methanol crossover in the membrane. The optimum properties and performances were presented by the SA/SGO membrane with a loading of 0.2 wt% SGO, which gave a proton conductivity of 13.2 × 10-3 Scm-1, and the methanol permeability was 1.535 × 10-7 cm2 s-1 at 25 °C, far below that of Nafion (25.1 × 10-7 cm2 s-1) at 25 °C. The mechanical properties of the sodium alginate polymer in terms of tensile strength and elongation at break were improved by the addition of SGO.

Electronic transition and electrical transport properties of delafossite CuCr1-xMgxO2 (0 ≤ x ≤ 12%) films prepared by the sol-gel method: A composition dependence study

NASA Astrophysics Data System (ADS)

Han, M. J.; Duan, Z. H.; Zhang, J. Z.; Zhang, S.; Li, Y. W.; Hu, Z. G.; Chu, J. H.

2013-10-01

Highly transparent CuCr1-xMgxO2 (0 ≤ x ≤ 12%) films were prepared on (001) sapphire substrates by sol-gel method. The microstructure, phonon modes, optical band gap, and electrical transport properties have been systematically discussed. It was found that Mg-doping improved the crystal quality and enhanced the (00l) preferred orientation. The spectral transmittance of films approaches about 70%-75% in the visible-near-infrared wavelength region. With increasing Mg-composition, the optical band gap first declines and climbs up due to the band gap renormalization and Burstein-Moss effect. The direct and indirect band gaps of CuCr0.94Mg0.06O2 film are 3.00 and 2.56 eV, respectively. In addition, it shows a crossover from the thermal activation behavior to that of three-dimensional variable range hopping from temperature-dependent electrical conductivity. The crossover temperature decreases with increasing Mg-doping composition, which can be ascribed to the change of spin-charge coupling between the hole and the local spin at Cr site. It should be noted that the electrical conductivity of CuCr1-xMgxO2 films becomes larger with increasing x value. The highest electrical conductivity of 3.85 S cm-1 at room temperature for x = 12% is four-order magnitude larger than that (8.81 × 10-4 S cm-1) for pure CuCrO2 film. The high spectral transmittance and larger conductivity indicate that Mg-doped CuCrO2 films are promising for optoelectronic device applications.

Application of Differential Evolutionary Optimization Methodology for Parameter Structure Identification in Groundwater Modeling

NASA Astrophysics Data System (ADS)

Chiu, Y.; Nishikawa, T.

2013-12-01

With the increasing complexity of parameter-structure identification (PSI) in groundwater modeling, there is a need for robust, fast, and accurate optimizers in the groundwater-hydrology field. For this work, PSI is defined as identifying parameter dimension, structure, and value. In this study, Voronoi tessellation and differential evolution (DE) are used to solve the optimal PSI problem. Voronoi tessellation is used for automatic parameterization, whereby stepwise regression and the error covariance matrix are used to determine the optimal parameter dimension. DE is a novel global optimizer that can be used to solve nonlinear, nondifferentiable, and multimodal optimization problems. It can be viewed as an improved version of genetic algorithms and employs a simple cycle of mutation, crossover, and selection operations. DE is used to estimate the optimal parameter structure and its associated values. A synthetic numerical experiment of continuous hydraulic conductivity distribution was conducted to demonstrate the proposed methodology. The results indicate that DE can identify the global optimum effectively and efficiently. A sensitivity analysis of the control parameters (i.e., the population size, mutation scaling factor, crossover rate, and mutation schemes) was performed to examine their influence on the objective function. The proposed DE was then applied to solve a complex parameter-estimation problem for a small desert groundwater basin in Southern California. Hydraulic conductivity, specific yield, specific storage, fault conductance, and recharge components were estimated simultaneously. Comparison of DE and a traditional gradient-based approach (PEST) shows DE to be more robust and efficient. The results of this work not only provide an alternative for PSI in groundwater models, but also extend DE applications towards solving complex, regional-scale water management optimization problems.

Exposure and response prevention helps adults with obsessive-compulsive disorder who do not respond to pharmacological augmentation strategies.

PubMed

McLean, Carmen P; Zandberg, Laurie J; Van Meter, Page E; Carpenter, Joseph K; Simpson, Helen Blair; Foa, Edna B

2015-12-01

Serotonin reuptake inhibitors (SRIs) are a first-line treatment for obsessive-compulsive disorder (OCD). Yet, most patients with OCD who are taking SRIs do not show excellent response. Recent studies show that augmenting SRIs with risperidone benefits a minority of patients. We evaluated the effectiveness of exposure and response prevention (EX/RP) among nonresponders to SRI augmentation with 8 weeks of risperidone or placebo. The study was conducted from January 2007 to August 2012. Nonresponders to SRI augmentation with risperidone or pill placebo (N = 32) in a randomized controlled trial for adults meeting DSM-IV-TR criteria for OCD were offered up to 17 twice-weekly EX/RP sessions. Independent evaluators, blind to treatment, evaluated patients at crossover baseline (week 8), midway through crossover treatment (week 12), post-EX/RP treatment (week 16), and follow-up (weeks 20, 24, 28, and 32). The primary outcome was OCD severity, measured with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Secondary outcomes were depression, quality of life, insight, and social functioning. Between crossover baseline and follow-up, nonresponders to SRI augmentation with risperidone or placebo who received EX/RP showed significant reductions in OCD symptoms and depression, as well as significant increases in insight, quality of life, and social functioning (all P < .001). Exposure and response prevention is an effective treatment for patients who have failed to respond to SRI augmentation with risperidone or placebo. This study adds to the body of evidence supporting the use of EX/RP with patients who continue to report clinically significant OCD symptoms after multiple pharmacologic trials. ClinicalTrials.gov Identifier: NCT00389493. © Copyright 2015 Physicians Postgraduate Press, Inc.

Impact of Intravenous Lysine Acetylsalicylate Versus Oral Aspirin on Prasugrel-Inhibited Platelets: Results of a Prospective, Randomized, Crossover Study (the ECCLIPSE Trial).

PubMed

Vivas, David; Martín, Agustín; Bernardo, Esther; Ortega-Pozzi, María Aranzazu; Tirado, Gabriela; Fernández, Cristina; Vilacosta, Isidre; Núñez-Gil, Iván; Macaya, Carlos; Fernández-Ortiz, Antonio

2015-05-01

Prasugrel and ticagrelor, new P2Y12-adenosine diphosphate receptor antagonists, are associated with greater pharmacodynamic inhibition and reduction of cardiovascular events compared with clopidogrel in patients with an acute coronary syndrome. However, evidence is lacking about the effects of achieving faster and stronger cyclooxygenase inhibition with intravenous lysine acetylsalicylate (LA) compared with oral aspirin on prasugrel-inhibited platelets. This was a prospective, randomized, single-center, open, 2-period crossover platelet function study conducted in 30 healthy volunteers. Subjects were randomly assigned to receive a loading dose of intravenous LA 450 mg plus oral prasugrel 60 mg or loading dose of aspirin 300 mg plus prasugrel 60 mg orally in a crossover fashion after a 2-week washout period between treatments. Platelet function was evaluated at baseline, 30 minutes, 1 h, 4 h, and 24 h using light transmission aggregometry and vasodilator-stimulated phosphoprotein phosphorylation. The primary end point of the study, inhibition of platelet aggregation after arachidonic acid 1.5 mmol/L at 30 minutes, was significantly higher in subjects treated with LA compared with aspirin: 85.3% versus 44.3%, respectively, P=0.003. This differential effect was observed at 1 hour (P=0.002) and 4 hours (P=0.048), but not at 24 hours. Subjects treated with LA presented less variability and faster and greater inhibition of platelet aggregation with arachidonic acid compared with aspirin. The administration of intravenous LA resulted in a significant reduction of platelet reactivity compared with oral aspirin on prasugrel-inhibited platelets. Loading dose of LA achieves an earlier platelet inhibition and with less variability than aspirin. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02243137. © 2015 American Heart Association, Inc.

Exercising Attention within the Classroom

ERIC Educational Resources Information Center

Hill, Liam; Williams, Justin H. G.; Aucott, Lorna; Milne, June; Thomson, Jenny; Greig, Jessie; Munro, Val; Mon-Williams, Mark

2010-01-01

Aim: To investigate whether increased physical exercise during the school day influenced subsequent cognitive performance in the classroom. Method: A randomized, crossover-design trial (two weeks in duration) was conducted in six mainstream primary schools (1224 children aged 8-11y). No data on sex was available. Children received a…

Low Crossover Polymer Electrolyte Membranes for Direct Methanol Fuel Cells

NASA Technical Reports Server (NTRS)

Prakash, G. K. Surya; Smart, Marshall; Atti, Anthony R.; Olah, George A.; Narayanan, S. R.; Valdez, T.; Surampudi, S.

1996-01-01

Direct Methanol Fuel Cells (DMFC's) using polymer electrolyte membranes are promising power sources for portable and vehicular applications. State of the art technology using Nafion(R) 117 membranes (Dupont) are limited by high methanol permeability and cost, resulting in reduced fuel cell efficiencies and impractical commercialization. Therefore, much research in the fuel cell field is focused on the preparation and testing of low crossover and cost efficient polymer electrolyte membranes. The University of Southern California in cooperation with the Jet Propulsion Laboratory is focused on development of such materials. Interpenetrating polymer networks are an effective method used to blend polymer systems without forming chemical links. They provide the ability to modify physical and chemical properties of polymers by optimizing blend compositions. We have developed a novel interpenetrating polymer network based on poly (vinyl - difluoride)/cross-linked polystyrenesulfonic acid polymer composites (PVDF PSSA). Sulfonation of polystyrene accounts for protonic conductivity while the non-polar, PVDF backbone provides structural integrity in addition to methanol rejection. Precursor materials were prepared and analyzed to characterize membrane crystallinity, stability and degree of interpenetration. USC JPL PVDF-PSSA membranes were also characterized to determine methanol permeability, protonic conductivity and sulfur distribution. Membranes were fabricated into membrane electrode assemblies (MEA) and tested for single cell performance. Tests include cell performance over a wide range of temperatures (20 C - 90 C) and cathode conditions (ambient Air/O2). Methanol crossover values are measured in situ using an in-line CO2 analyzer.

A simple, fast and accurate in-situ method to measure the rate of transport of redox species through membranes for lithium batteries

NASA Astrophysics Data System (ADS)

Meddings, Nina; Owen, John R.; Garcia-Araez, Nuria

2017-10-01

Lithium ion conducting membranes are important to protect the lithium metal electrode and act as a barrier to crossover species such as polysulphides in Li-S systems, redox mediators in Li-O2 cells or dissolved cathode species or electrolyte oxidation products in high voltage Li-ion batteries. We present an in-situ method for measuring permeability of membranes to crossover redox species. The method employs a 'Swagelok' cell design equipped with a glassy carbon working electrode, in which redox species are placed initially in the counter electrode compartment only. Permeability through the membrane, which separates working and counter electrodes, is determined using a square wave voltammetry technique that allows the concentration of crossover redox species to be evaluated over time with very high precision. We test the method using a model and well-behaved electrochemical system to demonstrate its sensitivity, reproducibility and reliability relative to alternative approaches. This new method offers advantages in terms of small electrolyte volume, and simple, fast, quantitative and in-situ measurement.

Human Cell Assays for Synthesis-Dependent Strand Annealing and Crossing over During Double-Strand Break Repair.

PubMed

Zapotoczny, Grzegorz; Sekelsky, Jeff

2017-04-03

DNA double-strand breaks (DSBs) are one of the most deleterious types of lesions to the genome. Synthesis-dependent strand annealing (SDSA) is thought to be a major pathway of DSB repair, but direct tests of this model have only been conducted in budding yeast and Drosophila To better understand this pathway, we developed an SDSA assay for use in human cells. Our results support the hypothesis that SDSA is an important DSB repair mechanism in human cells. We used siRNA knockdown to assess the roles of a number of helicases suggested to promote SDSA. None of the helicase knockdowns reduced SDSA, but knocking down BLM or RTEL1 increased SDSA. Molecular analysis of repair products suggests that these helicases may prevent long-tract repair synthesis. Since the major alternative to SDSA (repair involving a double-Holliday junction intermediate) can lead to crossovers, we also developed a fluorescent assay that detects crossovers generated during DSB repair. Together, these assays will be useful in investigating features and mechanisms of SDSA and crossover pathways in human cells. Copyright © 2017 Zapotoczny and Sekelsky.

Human Cell Assays for Synthesis-Dependent Strand Annealing and Crossing over During Double-Strand Break Repair

PubMed Central

Zapotoczny, Grzegorz; Sekelsky, Jeff

2017-01-01

DNA double-strand breaks (DSBs) are one of the most deleterious types of lesions to the genome. Synthesis-dependent strand annealing (SDSA) is thought to be a major pathway of DSB repair, but direct tests of this model have only been conducted in budding yeast and Drosophila. To better understand this pathway, we developed an SDSA assay for use in human cells. Our results support the hypothesis that SDSA is an important DSB repair mechanism in human cells. We used siRNA knockdown to assess the roles of a number of helicases suggested to promote SDSA. None of the helicase knockdowns reduced SDSA, but knocking down BLM or RTEL1 increased SDSA. Molecular analysis of repair products suggests that these helicases may prevent long-tract repair synthesis. Since the major alternative to SDSA (repair involving a double-Holliday junction intermediate) can lead to crossovers, we also developed a fluorescent assay that detects crossovers generated during DSB repair. Together, these assays will be useful in investigating features and mechanisms of SDSA and crossover pathways in human cells. PMID:28179392

Current conduction in junction gate field effect transistors. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kim, C.

1970-01-01

The internal physical mechanism that governs the current conduction in junction-gate field effect transistors is studied. A numerical method of analyzing the devices with different length-to-width ratios and doping profiles is developed. This method takes into account the two dimensional character of the electric field and the field dependent mobility. Application of the method to various device models shows that the channel width and the carrier concentration in the conductive channel decrease with increasing drain-to-source voltage for conventional devices. It also shows larger differential drain conductances for shorter devices when the drift velocity is not saturated. The interaction of the source and the drain gives the carrier accumulation in the channel which leads to the space-charge-limited current flow. The important parameters for the space-charge-limited current flow are found to be the L/L sub DE ratio and the crossover voltage.

Effects of Ayurvedic Oil-Dripping Treatment with Sesame Oil vs. with Warm Water on Sleep: A Randomized Single-Blinded Crossover Pilot Study.

PubMed

Tokinobu, Akiko; Yorifuji, Takashi; Tsuda, Toshihide; Doi, Hiroyuki

2016-01-01

Ayurvedic oil-dripping treatment (Shirodhara) is often used for treating sleep problems. However, few properly designed studies have been conducted, and the quantitative effect of Shirodhara is unclear. This study sought to quantitatively evaluate the effect of sesame oil Shirodhara (SOS) against warm water Shirodhara (WWS) on improving sleep quality and quality of life (QOL) among persons reporting sleep problems. This randomized, single-blinded, crossover study recruited 20 participants. Each participant received seven 30-minute sessions within 2 weeks with either liquid. The washout period was at least 2 months. The Shirodhara procedure was conducted by a robotic oil-drip system. The outcomes were assessed by the Pittsburgh Sleep Quality Index (PSQI) for sleep quality, Epworth Sleepiness Scale (ESS) for daytime sleepiness, World Health Organization Quality of Life 26 (WHO-QOL26) for QOL, and a sleep monitor instrument for objective sleep measures. Changes between baseline and follow-up periods were compared between the two types of Shirodhara. Analysis was performed with generalized estimating equations. Of 20 participants, 15 completed the study. SOS improved sleep quality, as measured by PSQI. The SOS score was 1.83 points lower (95% confidence interval [CI], -3.37 to -0.30) at 2-week follow-up and 1.73 points lower (95% CI, -3.84 to 0.38) than WWS at 6-week follow-up. Although marginally significant, SOS also improved QOL by 0.22 points at 2-week follow-up and 0.19 points at 6-week follow-up compared with WWS. After SOS, no beneficial effects were observed on daytime sleepiness or objective sleep measures. This pilot study demonstrated that SOS may be a safe potential treatment to improve sleep quality and QOL in persons with sleep problems.

Association between wind speed and the occurrence of sickle cell acute painful episodes: results of a case-crossover study

PubMed Central

Nolan, Vikki G.; Zhang, Yuqing; Lash, Timothy; Sebastiani, Paola; Steinberg, Martin H.

2015-01-01

Summary The role of the weather as a trigger of sickle cell acute painful episodes has long been debated. To more accurately describe the role of the weather as a trigger of painful events, we conducted a case-crossover study of the association between local weather conditions and the occurrence of painful episodes. From the Cooperative Study of Sickle Cell Disease, we identified 813 patients with sickle cell anaemia who had 3570 acute painful episodes. We found an association between wind speed and the onset of pain, specifically wind speed during the 24-h period preceding the onset of pain. Analysing wind speed as a categorical trait, showed a 13% increase (95% confidence interval: 3%, 24%) in odds of pain, when comparing the high wind speed to lower wind speed (P = 0.007). In addition, the association between wind speed and painful episodes was found to be stronger among men, particularly those in the warmer climate regions of the United States. These results are in agreement with another study that found an association between wind speed and hospital visits for pain in the United Kingdom, and lends support to physiological and clinical studies that have suggested that skin cooling is associated with sickle vasoocclusion and perhaps pain. PMID:18729854

Association between wind speed and the occurrence of sickle cell acute painful episodes: results of a case-crossover study.

PubMed

Nolan, Vikki G; Zhang, Yuqing; Lash, Timothy; Sebastiani, Paola; Steinberg, Martin H

2008-11-01

The role of the weather as a trigger of sickle cell acute painful episodes has long been debated. To more accurately describe the role of the weather as a trigger of painful events, we conducted a case-crossover study of the association between local weather conditions and the occurrence of painful episodes. From the Cooperative Study of Sickle Cell Disease, we identified 813 patients with sickle cell anaemia who had 3570 acute painful episodes. We found an association between wind speed and the onset of pain, specifically wind speed during the 24-h period preceding the onset of pain. Analysing wind speed as a categorical trait, showed a 13% increase (95% confidence interval: 3%, 24%) in odds of pain, when comparing the high wind speed to lower wind speed (P = 0.007). In addition, the association between wind speed and painful episodes was found to be stronger among men, particularly those in the warmer climate regions of the United States. These results are in agreement with another study that found an association between wind speed and hospital visits for pain in the United Kingdom, and lends support to physiological and clinical studies that have suggested that skin cooling is associated with sickle vasoocclusion and perhaps pain.

Alternative approaches to analytical designs in occupational injury epidemiology.

PubMed

Mittleman, M A; Maldonado, G; Gerberich, S G; Smith, G S; Sorock, G S

1997-08-01

In this paper, we discuss the theoretical framework upon which observational studies of occupational injuries are based. Following a general description of how causal effects are estimated, the challenges faced by researchers working in this area are outlined, with an emphasis on case-control studies. These challenges include defining the at-risk period for workers whose tasks change over time and whose hazard period may be very brief, evaluating the underreporting of both exposures and injuries, and considering the effects of multiple injuries per individual on study design and data analysis. We review both the theoretical and practical considerations in the design and conduct of traditional case-control studies, based on the collection of individual level data, as well as other approaches, such as using information culled from administrative and descriptive databases, and case-control studies in which the plant or work site is the unit of analysis. The case-crossover design is also reviewed and its utility for reducing confounding due to differences between individuals by self-matching is highlighted. While this design has not yet been applied to the work setting, its potential for increasing our understanding of the causes of acute-onset occupational injuries seems promising. Finally, a variety of hybrid designs are discussed, including combinations of case-control, case-crossover, and cohort designs.

Cross-Over Trial of Gabapentin and Memantine as Treatment for Acquired Nystagmus

PubMed Central

Thurtell, Matthew J.; Joshi, Anand C.; Leone, Alice C.; Tomsak, Robert L.; Kosmorsky, Gregory S.; Stahl, John S.; Leigh, R. John

2010-01-01

We conducted a masked, cross-over, therapeutic trial of gabapentin (1200mg/day) versus memantine (40mg/day) for acquired nystagmus in 10 patients (28–61 years; 7 female; MS: 3, post-stroke: 6, post-traumatic: 1). Nystagmus was pendular in 6 patients (oculopalatal tremor: 4, MS: 2) and jerk upbeat, hemi-seesaw, torsional, or upbeat-diagonal in each of the others. Both drugs reduced median eye speed (p<0.001), gabapentin by 32.8% and memantine by 27.8%, and improved visual acuity (p<0.05). Each patient improved with one or both drugs. Side-effects included unsteadiness with gabapentin and lethargy with memantine. Both drugs should be considered as treatment for acquired forms of nystagmus. PMID:20437565

Mesoscopic pairing without superconductivity

NASA Astrophysics Data System (ADS)

Hofmann, Johannes

2017-12-01

We discuss pairing signatures in mesoscopic nanowires with a variable attractive pairing interaction. Depending on the wire length, density, and interaction strength, these systems realize a simultaneous bulk-to-mesoscopic and BCS-BEC crossover, which we describe in terms of the parity parameter that quantifies the odd-even energy difference and generalizes the bulk Cooper pair binding energy to mesoscopic systems. We show that the parity parameter can be extracted from recent measurements of conductance oscillations in SrTiO3 nanowires by Cheng et al. [Nature (London) 521, 196 (2015), 10.1038/nature14398], where it marks the critical magnetic field that separates pair and single-particle currents. Our results place the experiment in the fluctuation-dominated mesoscopic regime on the BCS side of the crossover.

Family stress and parental responses to children's negative emotions: tests of the spillover, crossover, and compensatory hypotheses.

PubMed

Nelson, Jackie A; O'Brien, Marion; Blankson, A Nayena; Calkins, Susan D; Keane, Susan P

2009-10-01

The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers' and fathers' responses to children's negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor-Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined.

Crossover transition in flowing granular chains

NASA Astrophysics Data System (ADS)

Ulrich, Xialing; Fried, Eliot; Shen, Amy Q.

2009-09-01

We report on the dynamical and statistical behavior of flowing collections of granular chains confined two-dimensionally (2D) within a rotating tumbler. Experiments are conducted with systems of chains of fixed length, but various lengths are considered. The dynamics are punctuated by cascades of chains along a free-surface cascades, which drive the development of mixed porous/laminar packing arrangements in bulk. We investigate the conformation of the system, as characterized by the porosity of the flow region occupied by the chains and the mean-square end-to-end distance of the chains during flow. Both of these measures show crossover transitions from a 2D self-avoiding walk to a 2D random walk when the chain length becomes long enough to allow self-contact.

Application of Crossover Design for Conducting Rigorous Extension Evaluations

ERIC Educational Resources Information Center

Jayaratne, K. S. U.; Bird, Carolyn L.; McClelland, Jacquelyn W.

2013-01-01

With the increasing demand for accountability of Extension programming, Extension professionals need to apply rigorous evaluation designs. Randomized designs are useful to eliminate selection biases of program participants and to improve the accuracy of evaluation. However, randomized control designs are not practical to apply in Extension program…

Local and sex-specific biases in crossover vs. noncrossover outcomes at meiotic recombination hot spots in mice

PubMed Central

de Boer, Esther; Jasin, Maria; Keeney, Scott

2015-01-01

Meiotic recombination initiated by programmed double-strand breaks (DSBs) yields two types of interhomolog recombination products, crossovers and noncrossovers, but what determines whether a DSB will yield a crossover or noncrossover is not understood. In this study, we analyzed the influence of sex and chromosomal location on mammalian recombination outcomes by constructing fine-scale recombination maps in both males and females at two mouse hot spots located in different regions of the same chromosome. These include the most comprehensive maps of recombination hot spots in oocytes to date. One hot spot, located centrally on chromosome 1, behaved similarly in male and female meiosis: Crossovers and noncrossovers formed at comparable levels and ratios in both sexes. In contrast, at a distal hot spot, crossovers were recovered only in males even though noncrossovers were obtained at similar frequencies in both sexes. These findings reveal an example of extreme sex-specific bias in recombination outcome. We further found that estimates of relative DSB levels are surprisingly poor predictors of relative crossover frequencies between hot spots in males. Our results demonstrate that the outcome of mammalian meiotic recombination can be biased, that this bias can vary depending on location and cellular context, and that DSB frequency is not the only determinant of crossover frequency. PMID:26251527

Differential conductance fluctuation of curved nanographite sheets in the mesoscopic regime

NASA Astrophysics Data System (ADS)

Wang, Haomin; Choong, Catherine; Zhang, Jun; Teo, Kie Leong; Wu, Yihong

2008-02-01

Excess conductance fluctuations with peculiar temperature dependence from 1.4 to 250 K were observed in curved nanographite sheets with electrode gap lengths of 300 and 450 nm, whereas the conductance fluctuation is greatly suppressed above 4.2 K when the electrode gap lengths increase to 800 and 1000 nm. The former is discussed in the context of the presence of a small energy bandgap in the nanographite sheets, while the latter is attributed to the crossover from the coherent transport to diffusive transport regime.

A Case Study of Controlling Crossover in a Selection Hyper-heuristic Framework Using the Multidimensional Knapsack Problem.

PubMed

Drake, John H; Özcan, Ender; Burke, Edmund K

2016-01-01

Hyper-heuristics are high-level methodologies for solving complex problems that operate on a search space of heuristics. In a selection hyper-heuristic framework, a heuristic is chosen from an existing set of low-level heuristics and applied to the current solution to produce a new solution at each point in the search. The use of crossover low-level heuristics is possible in an increasing number of general-purpose hyper-heuristic tools such as HyFlex and Hyperion. However, little work has been undertaken to assess how best to utilise it. Since a single-point search hyper-heuristic operates on a single candidate solution, and two candidate solutions are required for crossover, a mechanism is required to control the choice of the other solution. The frameworks we propose maintain a list of potential solutions for use in crossover. We investigate the use of such lists at two conceptual levels. First, crossover is controlled at the hyper-heuristic level where no problem-specific information is required. Second, it is controlled at the problem domain level where problem-specific information is used to produce good-quality solutions to use in crossover. A number of selection hyper-heuristics are compared using these frameworks over three benchmark libraries with varying properties for an NP-hard optimisation problem: the multidimensional 0-1 knapsack problem. It is shown that allowing crossover to be managed at the domain level outperforms managing crossover at the hyper-heuristic level in this problem domain.

Dimensional crossover of electron weak localization in ZnO/TiO{sub x} stacked layers grown by atomic layer deposition

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

Saha, D., E-mail: sahaphys@gmail.com, E-mail: pmisra@rrcat.gov.in; Misra, P., E-mail: sahaphys@gmail.com, E-mail: pmisra@rrcat.gov.in; Joshi, M. P.

2016-01-25

We report on the dimensional crossover of electron weak localization in ZnO/TiO{sub x} stacked layers having well-defined and spatially-localized Ti dopant profiles along film thickness. These films were grown by in situ incorporation of sub-monolayer TiO{sub x} on the growing ZnO film surface and subsequent overgrowth of thin conducting ZnO spacer layer using atomic layer deposition. Film thickness was varied in the range of ∼6–65 nm by vertically stacking different numbers (n = 1–7) of ZnO/TiO{sub x} layers of nearly identical dopant-profiles. The evolution of zero-field sheet resistance (R{sub ◻}) versus temperature with decreasing film thickness showed a metal to insulator transition. Onmore » the metallic side of the metal-insulator transition, R{sub ◻}(T) and magnetoresistance data were found to be well corroborated with the theoretical framework of electron weak localization in the diffusive transport regime. The temperature dependence of both R{sub ◻} and inelastic scattering length provided strong evidence for a smooth crossover from 2D to 3D weak localization behaviour. Results of this study provide deeper insight into the electron transport in low-dimensional n-type ZnO/TiO{sub x} stacked layers which have potential applications in the field of transparent oxide electronics.« less

A Crossover Study of Risperidone in Children, Adolescents and Adults with Mental Retardation

ERIC Educational Resources Information Center

Hellings, Jessica A.; Zarcone, Jennifer R.; Reese, R. Matthew; Valdovinos, Maria G.; Marquis, Janet G.; Fleming, Kandace K.; Schroeder, Stephen R.

2006-01-01

Risperidone has shown safety and efficacy for aggressive and destructive behaviors in short-term studies. This longer-duration study includes a broad sample. Forty subjects, aged 8-56 years (mean=22), all with mental retardation and 36 with autism spectrum disorders participated in this 22-week crossover study, with 24 weeks of open maintenance…

Predictive Factors for Patients Undergoing ASD Device Occlusion Who "Crossover" to Surgery.

PubMed

Mulukutla, Venkatachalam; Qureshi, Athar M; Pignatelli, Ricardo; Ing, Frank F

2018-03-01

The aim of this study was to define characteristics of those patients who are referred for device closure of an Atrial septal defect (ASD), but identified to "crossover" surgery. All patients who underwent surgical and device (Amplatzer or Helex occluder) closures of secundum ASDs from 2001 to 2010 were reviewed and organized into three groups: surgical closure, device closure, and "crossover" group. 369 patients underwent ASD closure (265 device, 104 surgical). 42 of the 265 patients referred for device closure "crossed over" to the surgical group at various stages of the catheterization procedure. The device group had defect size measuring 14.2 mm (mean) and an ASD index (Defect Size (mm)/BSA) of 14.0 compared to the corresponding values in the surgical group (20.1 mm, ASD index 25.9) (P < 0.001) and in the "crossover" group (20.7 mm, 22.6 ASD index) (P < 0.001). 79 patients in the device group had a deficient rim, and 86% were located in the retroaortic region. 33 patients in the "crossover" group had deficient rims with 70% deficiency in the posterior/inferior rim. The device group with deficient rims had an ASD index of 14.7 compared with the crossover group ASD index of 23.8 (P < 0.001). Comparing the device and "crossover" groups, an ASD index greater than 23.7 had a 90% specificity in "crossing over" to surgery. The crossover and surgical groups had statistically larger ASD defect size indexes compared with the device group. Deficient rim in the posterior/inferior rim is associated with a large ASD size index which is a predictive factor for crossing over to surgery. Catheterization did not negatively impact surgical results in the "crossover" group.

A Single-Dose Crossover Pharmacokinetic Comparison Study of Oral, Rectal and Topical Quetiapine in Healthy Adults.

PubMed

Leung, Jonathan G; Nelson, Sarah; Cunningham, Julie L; Thompson, Virginia H; Bobo, William V; Kung, Simon; Dierkhising, Ross A; Plevak, Matthew F; Lapid, Maria I

2016-08-01

Quetiapine is an oral atypical antipsychotic drug commonly used to treat a large number of neuropsychiatric disorders and conditions. However, a substantial number of patients who may benefit from treatment with quetiapine are unable to ingest quetiapine or other medications by mouth and thus require alternative routes of administration. There are currently no studies evaluating non-oral compounded dosage forms of quetiapine. We conducted a single-dose open-label crossover pharmacokinetic study in 10 healthy adults to determine whether quetiapine compounded as a rectal suppository or a topical cream achieved absorption similar to that achieved by a commercially available oral formulation. Rectal quetiapine produced an area under the plasma concentration-time curve from time zero to infinity (AUC∞) approximately 90 % greater than that produced by an equal (milligram per milligram) dose of oral quetiapine (15,333 ng/mL versus 8118.8 ng/mL, p = 0.005). However, only two of ten subjects who received topical quetiapine had detectable serum levels. When detected, serum levels achieved with topical quetiapine were delayed and low in comparison with those produced by the oral and rectal dosage forms. Our results suggest that rectal, but not topical, quetiapine may be useful in clinical settings. Clinical outcome studies of rectal quetiapine are needed.

Bioequivalence of fixed-dose combination RIN®-150 to each reference drug in loose combination.

PubMed

Wang, H F; Wang, R; O'Gorman, M; Crownover, P; Damle, B

2015-03-01

RIN(®)-150 is a fixed-dose combination (FDC) tablet containing rifampicin (RMP, 150 mg) and isoniazid (INH, 75 mg) developed for the treatment of tuberculosis. This study was conducted at a single center: the Pfizer Clinical Research Unit in Singapore. To demonstrate bioequivalence of each drug component between RIN-150 and individual products in a loose combination. This was a randomized, open-label, single-dose, two-way crossover study. Subjects received single doses of RIN-150 or two individual reference products under fasting conditions in a crossover fashion, with at least 7 days washout between doses. The primary measures for comparison were peak plasma concentration (Cmax) and the area under plasma concentration-time curve (AUC). Of 28 subjects enrolled, 26 completed the study. The adjusted geometric mean ratios of Cmax and AUClast between the FDC and single-drug references and 90% confidence intervals were respectively 91.63% (90%CI 83.13-101.01) and 95.45% (90%CI 92.07-98.94) for RMP, and 107.58% (90%CI 96.07-120.47) and 103.45% (90%CI 99.33-107.75) for INH. Both formulations were generally well tolerated in this study. The RIN-150 FDC tablet formulation is bioequivalent to the two single-drug references for RMP and INH at equivalent doses.

Bioequivalence of fixed-dose combination Myrin®-P Forte and reference drugs in loose combination.

PubMed

Wang, H F; Wang, R; O'Gorman, M; Crownover, P; Naqvi, A; Jafri, I

2013-12-01

Myrin®-P Forte is a fixed-dose combination (FDC) tablet containing rifampicin (RMP, 150 mg), isoniazid (INH, 75 mg), ethambutol (EMB) hydrochloride (275 mg) and pyrazinamide (PZA, 400 mg) developed for the treatment of tuberculosis (TB). This study was conducted at a single centre--the Pfizer Clinical Research Unit in Singapore. To demonstrate the bioequivalence of each drug component of the Myrin-P Forte FDC and the individual product in loose combination. In a randomized, open-label, single-dose, two-way, crossover study, subjects received single doses of Myrin-P Forte or four individual products under fasting conditions in a crossover fashion with at least 7 days washout between doses. The primary measures for comparison were peak plasma concentration (C(max)) and the area under plasma concentration-time curve (AUC). Of 36 subjects enrolled, 35 completed the study. The adjusted geometric mean ratios and 90% confidence intervals for C(max) and AUC values were completely contained within bioequivalence limits (80%, 125%) for all four drugs in both formulations. Both treatments were generally well tolerated in the study. The Myrin-P Forte FDC tablet formulation is bioequivalent to the four single-drug references for RMP, INH, EMB hydrochloride and PZA at equivalent doses.

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Using Sit-Stand Workstations to Decrease Sedentary Time in Office Workers: A Randomized Crossover Trial

PubMed Central

Dutta, Nirjhar; Koepp, Gabriel A.; Stovitz, Steven D.; Levine, James A.; Pereira, Mark A.

2014-01-01

Objective: This study was conducted to determine whether installation of sit-stand desks (SSDs) could lead to decreased sitting time during the workday among sedentary office workers. Methods: A randomized cross-over trial was conducted from January to April, 2012 at a business in Minneapolis. 28 (nine men, 26 full-time) sedentary office workers took part in a 4 week intervention period which included the use of SSDs to gradually replace 50% of sitting time with standing during the workday. Physical activity was the primary outcome. Mood, energy level, fatigue, appetite, dietary intake, and productivity were explored as secondary outcomes. Results: The intervention reduced sitting time at work by 21% (95% CI 18%–25%) and sedentary time by 4.8 min/work-hr (95% CI 4.1–5.4 min/work-hr). For a 40 h work-week, this translates into replacement of 8 h of sitting time with standing and sedentary time being reduced by 3.2 h. Activity level during non-work hours did not change. The intervention also increased overall sense of well-being, energy, decreased fatigue, had no impact on productivity, and reduced appetite and dietary intake. The workstations were popular with the participants. Conclusion: The SSD intervention was successful in increasing work-time activity level, without changing activity level during non-work hours. PMID:24968210

Efficacy of piracetam in the treatment of tardive dyskinesia in schizophrenic patients: a randomized, double-blind, placebo-controlled crossover study.

PubMed

Libov, Igor; Miodownik, Chanoch; Bersudsky, Yuly; Dwolatzky, Tzvi; Lerner, Vladimir

2007-07-01

Piracetam is a potent antioxidant, a cerebral neuroprotector, a neuronal metabolic enhancer, and a brain integrative agent. More than 20 years ago, an intravenous preparation of piracetam demonstrated an improvement in the symptoms of tardive dyskinesia. The aim of our study was to reexamine the efficacy of piracetam in the treatment of tardive dyskinesia using an oral preparation. The study was conducted at the Be'er Sheva Mental Health Center from May 2003 to December 2004 and involved a 9-week, double-blind, crossover, placebo-controlled trial assessing 40 DSM-IV schizophrenic and schizo-affective patients with DSM-IV-TR tardive dyskinesia. All study subjects received their usual antipsychotic treatment. Initially, subjects were randomly assigned to receive 4 weeks of treatment with either piracetam (4800 mg/day) or placebo. Thereafter, following a washout period of 1 week, they entered the crossover phase of the study for a further 4 weeks. The change in score of the Extrapyramidal Symptom Rating Scale from baseline to the study endpoint was the primary outcome measure. The mean decrease in score from baseline to endpoint in the clinical global impression subscale in patients treated with piracetam was 1.1 points compared to 0.1 points in the placebo group (p = .004). The mean decrease in the tardive parkinsonism subscale was 8.7 points in patients treated with piracetam and 0.6 points in those on placebo (p = .001). The mean decrease in the tardive dyskinesia subscale was 3.0 points in the piracetam group in contrast to deterioration of condition in the placebo group by -0.2 points (p = .003). Piracetam appears to be effective in reducing symptoms of tardive dyskinesia. The specific mechanism by which piracetam may attenuate symptoms of tardive dyskinesia needs to be further evaluated. ClinicalTrials.gov identifier NCT00190008.

Effect of Crossover in Oncology Clinical Trials on Evidence Levels in Early Benefit Assessment in Germany.

PubMed

Isbary, Georg; Staab, Thomas R; Amelung, Volker E; Dintsios, Charalabos-Markos; Iking-Konert, Christof; Nesurini, Sonja Mariotti; Walter, Miriam; Ruof, Jörg

2018-06-01

In oncology clinical trials, crossover is used frequently but may lead to uncertainties regarding treatment effects. To investigate the handling of evidence from crossover trials by the European Medicines Agency (EMA) and the German Federal Joint Committee (G-BA). For oncology medicines with early benefit assessments before January 2015, presence of crossover, clinical data, EMA requests for additional data, and G-BA benefit ratings/evidence levels were analyzed from manufacturers' dossiers, G-BA appraisals, European Public Assessment Reports, and original publications. Eleven of 21 benefit assessments included crossover trials. Significant intergroup differences (P < 0.05) in overall survival (OS) were noted in 7 of 11 trials with and 7 of 10 without crossover. For 6 of 11 medicines with crossover, these were demonstrated before crossover. Treatment effects generally worsened with increasing proportions of crossover. The EMA requested additional data more frequently if crossover was performed, particularly if no OS data were available before crossover. The G-BA granted a considerable benefit to 73% of medicines with crossover and 40% of those without. Evidence levels were intermediate for 50% and 75%, respectively. None of the medicines received the highest evidence level. In G-BA appraisals, oncology medicines with crossover received better additional benefit ratings, but were assigned lower evidence levels, than those without. The five medicines with crossover after progression were assigned lower evidence levels than the six medicines with crossover after demonstration of superior OS, indicating that the way in which crossover is implemented may be one factor influencing the assignment of evidence levels by the G-BA. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Hyperbaric Oxygen Therapy in the Treatment of Chronic Mild-Moderate Blast-Induced Traumatic Brain Injury Post-Concussion Syndrome (PCS) and Post Traumatic Stress Disorder (PTSD)

DTIC Science & Technology

2017-10-01

a randomized sham- controlled double-blind design with the sham- control group receiving slightly pressurized air at the beginning and end of each... controlled ( non -treatment, non -sham) single-arm crossover single-blind study. The scope of the project is to recruit, enroll, test, treat, re-test and...the P.I. conducted a non - controlled pilot trial of hyperbaric oxygen therapy (HBOT 1.5 atmospheres absolute/60 minutes, twice/day, 40 treatments

Cotunneling and polaronic effect in granular systems

NASA Astrophysics Data System (ADS)

Ioselevich, A. S.; Sivak, V. V.

2017-06-01

We theoretically study the conductivity in arrays of metallic grains due to the variable-range multiple cotunneling of electrons with short-range (screened) Coulomb interaction. The system is supposed to be coupled to random stray charges in the dielectric matrix that are only loosely bounded to their spatial positions by elastic forces. The flexibility of the stray charges gives rise to a polaronic effect, which leads to the onset of Arrhenius-type conductivity behavior at low temperatures, replacing conventional Mott variable-range hopping. The effective activation energy logarithmically depends on temperature due to fluctuations of the polaron barrier heights. We present the unified theory that covers both weak and strong polaron effect regimes of hopping in granular metals and describes the crossover from elastic to inelastic cotunneling.

Acute Caffeinated Coffee Consumption Does not Improve Time Trial Performance in an 800-m Run: A Randomized, Double-Blind, Crossover, Placebo-Controlled Study.

PubMed

Marques, Alexandre C; Jesus, Alison A; Giglio, Bruna M; Marini, Ana C; Lobo, Patrícia C B; Mota, João F; Pimentel, Gustavo D

2018-05-23

Studies evaluating caffeinated coffee (CAF) can reveal ergogenic effects; however, studies on the effects of caffeinated coffee on running are scarce and controversial. To investigate the effects of CAF consumption compared to decaffeinated coffee (DEC) consumption on time trial performances in an 800-m run in overnight-fasting runners. A randomly counterbalanced, double-blind, crossover, placebo-controlled study was conducted with 12 healthy adult males with experience in amateur endurance running. Participants conducted two trials on two different occasions, one day with either CAF or DEC, with a one-week washout. After arriving at the data collection site, participants consumed the soluble CAF (5.5 mg/kg of caffeine) or DEC and after 60 min the run was started. Before and after the 800-m race, blood pressure and lactate and glucose concentrations were measured. At the end of the run, the ratings of perceived exertion (RPE) scale was applied. The runners were light consumers of habitual caffeine, with an average ingestion of 91.3 mg (range 6⁻420 mg/day). Time trial performances did not change between trials (DEF: 2.38 + 0.10 vs. CAF: 2.39 + 0.09 min, p = 0.336), nor did the RPE (DEC: 16.5 + 2.68 vs. CAF: 17.0 + 2.66, p = 0.326). No difference between the trials was observed for glucose and lactate concentrations, or for systolic and diastolic blood pressure levels. CAF consumption failed to enhance the time trial performance of an 800-m run in overnight-fasting runners, when compared with DEC ingestion. In addition, no change was found in RPE, blood pressure levels, or blood glucose and lactate concentrations between the two trials.

Effects of Ethnic Attributes on the Quality of Family Planning Services in Lima, Peru: A Randomized Crossover Trial

PubMed Central

Planas, Maria-Elena; García, Patricia J.; Bustelo, Monserrat; Carcamo, Cesar P.; Martinez, Sebastian; Nopo, Hugo; Rodriguez, Julio; Merino, Maria-Fernanda; Morrison, Andrew

2015-01-01

Most studies reporting ethnic disparities in the quality of healthcare come from developed countries and rely on observational methods. We conducted the first experimental study to evaluate whether health providers in Peru provide differential quality of care for family planning services, based on the indigenous or mestizo (mixed ethnoracial ancestry) profile of the patient. In a crossover randomized controlled trial conducted in 2012, a sample of 351 out of the 408 public health establishments in Metropolitan Lima, Peru were randomly assigned to receive unannounced simulated patients enacting indigenous and mestizo profiles (sequence-1) or mestizo and then indigenous profiles (sequence-2), with a five week wash-out period. Both ethnic profiles used the same scripted scenario for seeking contraceptive advice but had distinctive cultural attributes such as clothing, styling of hair, make-up, accessories, posture and patterns of movement and speech. Our primary outcome measure of quality of care is the proportion of technical tasks performed by providers, as established by Peruvian family planning clinical guidelines. Providers and data analysts were kept blinded to the allocation. We found a non-significant mean difference of -0·7% (p = 0·23) between ethnic profiles in the percentage of technical tasks performed by providers. However we report large deficiencies in the compliance with quality standards of care for both profiles. Differential provider behaviour based on the patient's ethnic profiles compared in the study did not contribute to deficiencies in family planning outcomes observed. The study highlights the need to explore other determinants for poor compliance with quality standards, including demand and supply side factors, and calls for interventions to improve the quality of care for family planning services in Metropolitan Lima. PMID:25671664

Effects of ethnic attributes on the quality of family planning services in Lima, Peru: a randomized crossover trial.

PubMed

Planas, Maria-Elena; García, Patricia J; Bustelo, Monserrat; Carcamo, Cesar P; Martinez, Sebastian; Nopo, Hugo; Rodriguez, Julio; Merino, Maria-Fernanda; Morrison, Andrew

2015-01-01

Most studies reporting ethnic disparities in the quality of healthcare come from developed countries and rely on observational methods. We conducted the first experimental study to evaluate whether health providers in Peru provide differential quality of care for family planning services, based on the indigenous or mestizo (mixed ethnoracial ancestry) profile of the patient. In a crossover randomized controlled trial conducted in 2012, a sample of 351 out of the 408 public health establishments in Metropolitan Lima, Peru were randomly assigned to receive unannounced simulated patients enacting indigenous and mestizo profiles (sequence-1) or mestizo and then indigenous profiles (sequence-2), with a five week wash-out period. Both ethnic profiles used the same scripted scenario for seeking contraceptive advice but had distinctive cultural attributes such as clothing, styling of hair, make-up, accessories, posture and patterns of movement and speech. Our primary outcome measure of quality of care is the proportion of technical tasks performed by providers, as established by Peruvian family planning clinical guidelines. Providers and data analysts were kept blinded to the allocation. We found a non-significant mean difference of -0.7% (p = 0.23) between ethnic profiles in the percentage of technical tasks performed by providers. However we report large deficiencies in the compliance with quality standards of care for both profiles. Differential provider behaviour based on the patient's ethnic profiles compared in the study did not contribute to deficiencies in family planning outcomes observed. The study highlights the need to explore other determinants for poor compliance with quality standards, including demand and supply side factors, and calls for interventions to improve the quality of care for family planning services in Metropolitan Lima.

Temperature Dependence of Electric Transport in Few-layer Graphene under Large Charge Doping Induced by Electrochemical Gating

PubMed Central

Gonnelli, R. S.; Paolucci, F.; Piatti, E.; Sharda, Kanudha; Sola, A.; Tortello, M.; Nair, Jijeesh R.; Gerbaldi, C.; Bruna, M.; Borini, S.

2015-01-01

The temperature dependence of electric transport properties of single-layer and few-layer graphene at large charge doping is of great interest both for the study of the scattering processes dominating the conductivity at different temperatures and in view of the theoretically predicted possibility to reach the superconducting state in such extreme conditions. Here we present the results obtained in 3-, 4- and 5-layer graphene devices down to 3.5 K, where a large surface charge density up to about 6.8·1014 cm−2 has been reached by employing a novel polymer electrolyte solution for the electrochemical gating. In contrast with recent results obtained in single-layer graphene, the temperature dependence of the sheet resistance between 20 K and 280 K shows a low-temperature dominance of a T2 component – that can be associated with electron-electron scattering – and, at about 100 K, a crossover to the classic electron-phonon regime. Unexpectedly, this crossover does not show any dependence on the induced charge density, i.e. on the large tuning of the Fermi energy. PMID:25906088

Bioequivalence of two lansoprazole delayed release capsules 30 mg in healthy male volunteers under fasting, fed and fasting-applesauce conditions: a partial replicate crossover study design to estimate the pharmacokinetics of highly variable drugs.

PubMed

Thota, S; Khan, S M; Tippabhotla, S K; Battula, R; Gadiko, C; Vobalaboina, V

2013-11-01

An open-label, 2-treatment, 3-sequence, 3-period, single-dose, partial replicate crossover studies under fasting (n=48), fed (n=60) and fasting-applesauce (n=48) (sprinkled on one table spoonful of applesauce) modalities were conducted in healthy adult male volunteers to evaluate bioequivalence between 2 formulations of lansoprazole delayed release capsules 30 mg. In all the 3 studies, as per randomization, either test or reference formulations were administered in a crossover manner with a required washout period of at least 7 days. Blood samples were collected adequately (0-24 h) to determine lansoprazole plasma concentrations using a validated LC-MS/MS analytical method. To characterize the pharmacokinetic parameters (Cmax, AUC0-t, AUC0-∞, Tmax, Kel and T1/2) of lansoprazole, non-compartmental analysis and ANOVA was applied on ln-transformed values. The bioequivalence was tested based on within-subject variability of the reference formulation. In fasting and fed studies (within-subject variability>30%) bioequivalence was evaluated with scaled average bioequivalence, hence for the pharmacokinetic parameters Cmax, AUC0-t and AUC0-∞, the 95% upper confidence bound for (μT-μR)2-θσ2 WR was ≤0, and the point estimates (test-to-reference ratio) were within the regulatory acceptance limit 80.00-125.00%. In fasting-applesauce study (within-subject variability<30%) bioequivalence was evaluated with average bioequivalence, the 90% CI of ln-transformed data of Cmax, AUC0-t and AUC0-∞ were within the regulatory acceptance limit 80.00-125.00%. Based on these aforesaid statistical inferences, it was concluded that the test formulation is bioequivalent to reference formulation. © Georg Thieme Verlag KG Stuttgart · New York.

A systematic review identifies shortcomings in the reporting of crossover trials in chronic painful conditions.

PubMed

Straube, Sebastian; Werny, Benedikt; Friede, Tim

2015-12-01

To investigate the reporting of study features of interest in abstracts and full texts of journal publications of crossover trials in chronic painful conditions. Systematic review based on a MEDLINE (PubMed) search (January 1990-August 2014). Ninety-eight publications on crossover studies with 3,513 study participants were eligible for inclusion. Double-blind status and randomized allocation to treatment groups are commonly reported in both abstracts and full texts (90 of 98 publications and 82 of 98 publications, respectively). Adverse events are reported in both abstract and full text in 49 of 98 publications and in the full text only in 44 of 98. A breakdown of results by treatment period is provided only in 23 of 98 publications, and if so, is reported only in the full text, never in the abstract. There is a time trend for the reporting of randomization in abstracts; it is more likely to be reported in recent studies (P = 0.0094). No time trends are detected in the reporting of double-blind status (P = 0.1087) and adverse events (P = 0.6084). The reporting of adverse events in the abstract and the reporting of results specified by crossover period in the full texts of journal publications on crossover pain trials should be improved. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficacy of methylphenidate in the rehabilitation of attention following traumatic brain injury: a randomised, crossover, double blind, placebo controlled inpatient trial.

PubMed

Willmott, C; Ponsford, J

2009-05-01

Most previous studies evaluating the use of methylphenidate following traumatic brain injury (TBI) have been conducted many years post-injury. This study evaluated the efficacy of methylphenidate in facilitating cognitive function in the inpatient rehabilitation phase. 40 participants with moderate-severe TBI (mean 68 days post-injury) were recruited into a randomised, crossover, double blind, placebo controlled trial. Methylphenidate was administered at a dose of 0.3 mg/kg twice daily and lactose in identical capsules served as placebo. Methylphenidate and placebo administration was randomised in a crossover design across six sessions over a 2 week period. Primary efficacy outcomes were neuropsychological tests of attention. No participants were withdrawn because of side effects or adverse events. Methylphenidate significantly increased speed of information processing on the Symbol Digit Modalities Test (95% CI 0.30 to 2.95, Cohen's d = 0.39, p = 0.02), Ruff 2 and 7 Test-Automatic Condition (95% CI 1.38 to 6.12, Cohen's d = 0.51, p = 0.003), Simple Selective Attention Task (95% CI -58.35 to -17.43, Cohen's d = 0.59, p = 0.001) and Dissimilar Compatible (95% CI -70.13 to -15.38, Cohen's d = 0.51, p = 0.003) and Similar Compatible (95% CI -74.82 to -19.06, Cohen's d = 0.55, p = 0.002) conditions of the Four Choice Reaction Time Task. Those with more severe injuries and slower baseline information processing speed demonstrated a greater drug response. Methylphenidate enhances information processing speed in the inpatient rehabilitation phase following TBI. This trial is registered with the Australian New Zealand Clinical Trials Registry (12607000503426).

Spin state switching in iron coordination compounds

PubMed Central

Gaspar, Ana B; Garcia, Yann

2013-01-01

Summary The article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices. The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST) and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II), with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligo- and polynuclear iron(II) complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property. PMID:23504535

Local and sex-specific biases in crossover vs. noncrossover outcomes at meiotic recombination hot spots in mice.

PubMed

de Boer, Esther; Jasin, Maria; Keeney, Scott

2015-08-15

Meiotic recombination initiated by programmed double-strand breaks (DSBs) yields two types of interhomolog recombination products, crossovers and noncrossovers, but what determines whether a DSB will yield a crossover or noncrossover is not understood. In this study, we analyzed the influence of sex and chromosomal location on mammalian recombination outcomes by constructing fine-scale recombination maps in both males and females at two mouse hot spots located in different regions of the same chromosome. These include the most comprehensive maps of recombination hot spots in oocytes to date. One hot spot, located centrally on chromosome 1, behaved similarly in male and female meiosis: Crossovers and noncrossovers formed at comparable levels and ratios in both sexes. In contrast, at a distal hot spot, crossovers were recovered only in males even though noncrossovers were obtained at similar frequencies in both sexes. These findings reveal an example of extreme sex-specific bias in recombination outcome. We further found that estimates of relative DSB levels are surprisingly poor predictors of relative crossover frequencies between hot spots in males. Our results demonstrate that the outcome of mammalian meiotic recombination can be biased, that this bias can vary depending on location and cellular context, and that DSB frequency is not the only determinant of crossover frequency. © 2015 de Boer et al.; Published by Cold Spring Harbor Laboratory Press.

The Sonoma Water Evaluation Trial (SWET): A randomized drinking water intervention trial to reduce gastrointestinal illness in older adults

EPA Science Inventory

Objectives. We estimate the risk of highly credible gastrointestinal illness (HCGI) among adults 55 and older in a community drinking tap water meeting current U.S. standards. Methods. We conducted a randomized, triple-blinded, crossover trial in 714 households (988 indiv...

Variation and Evolution of the Meiotic Requirement for Crossing Over in Mammals.

PubMed

Dumont, Beth L

2017-01-01

The segregation of homologous chromosomes at the first meiotic division is dependent on the presence of at least one well-positioned crossover per chromosome. In some mammalian species, however, the genomic distribution of crossovers is consistent with a more stringent baseline requirement of one crossover per chromosome arm. Given that the meiotic requirement for crossing over defines the minimum frequency of recombination necessary for the production of viable gametes, determining the chromosomal scale of this constraint is essential for defining crossover profiles predisposed to aneuploidy and understanding the parameters that shape patterns of recombination rate evolution across species. Here, I use cytogenetic methods for in situ imaging of crossovers in karyotypically diverse house mice (Mus musculus domesticus) and voles (genus Microtus) to test how chromosome number and configuration constrain the distribution of crossovers in a genome. I show that the global distribution of crossovers in house mice is thresholded by a minimum of one crossover per chromosome arm, whereas the crossover landscape in voles is defined by a more relaxed requirement of one crossover per chromosome. I extend these findings in an evolutionary metaanalysis of published recombination and karyotype data for 112 mammalian species and demonstrate that the physical scale of the genomic crossover distribution has undergone multiple independent shifts from one crossover per chromosome arm to one per chromosome during mammalian evolution. Together, these results indicate that the chromosomal scale constraint on crossover rates is itself a trait that evolves among species, a finding that casts light on an important source of crossover rate variation in mammals. Copyright © 2017 by the Genetics Society of America.

Samarium Hexaboride: The First True 3D Topological Insulator?

NASA Astrophysics Data System (ADS)

Wolgast, Steven G.

The recent theoretical prediction of a topologically protected surface state in the mixed-valent insulator SmB6 has motivated a series of charge transport studies, which are presented here. It is first studied using a specialized configuration designed to distinguish bulk-dominated conduction from surface-dominated conduction. As the material is cooled below 4 K, it exhibits a crossover from thermally activated bulk transport to metallic surface conduction with a fully insulating bulk. The robustness and magnitude of the surface conductivity, as is manifest in the literature of SmB6, is strong evidence for the topological insulator (TI) metallic surface states predicted for this material. This resolves a decades-old puzzle surrounding the low-temperature behavior of SmB6. Next, the magnetotransport properties of the surface are investigated using a Corbino disk geometry, which can directly measure the conductivity of individual surfaces. Both (011) and (001) crystal surfaces show a strong negative magnetoresistance at all magnetic field angles, due primarily to changes in the carrier density. The low mobility value accounts for the failure so far to observe Shubnikov-de Haas oscillations below 95 T. Small variations in the mobility and temperature dependence suggest a suppression of Kondo scattering from native oxide-layer magnetic moments. At low fields, a dynamical field-sweep-rate-dependent hysteretic behavior is observed. It persists at the slowest sweep rates, and cannot be explained by quantum interference corrections; it is likely due to extrinsic effects such as the magnetocaloric effect or glassy ordering of the native oxide moments. Pulsed magnetic field measurements up to 60 T at temperatures throughout the crossover regime clearly distinguish the surface magnetoresistance from the bulk magnetoresistance. The bulk magnetoresistance is due to a reduction in the bulk gap with increasing magnetic field. Finally, small subsurface cracks formed in SmB6 via systematic scratching or sanding results in a counter-intuitive increase in the electrical conduction due to the unique surface-conducting property of TIs, strengthening the building case for SmB 6's topological nature. This material is attractive as a TI because its bulk is fully insulating at a readily achieved 2 K, but it presents a large number of scientific mysteries and experimental challenges for future research.

Family Stress and Parental Responses to Children’s Negative Emotions: Tests of the Spillover, Crossover, and Compensatory Hypotheses

PubMed Central

Nelson, Jackie A.; O’Brien, Marion; Blankson, A. Nayena; Calkins, Susan D.; Keane, Susan P.

2010-01-01

The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers’ and fathers’ responses to children’s negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor–Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined. PMID:19803603

Checking distributional assumptions for pharmacokinetic summary statistics based on simulations with compartmental models.

PubMed

Shen, Meiyu; Russek-Cohen, Estelle; Slud, Eric V

2016-08-12

Bioequivalence (BE) studies are an essential part of the evaluation of generic drugs. The most common in vivo BE study design is the two-period two-treatment crossover design. AUC (area under the concentration-time curve) and Cmax (maximum concentration) are obtained from the observed concentration-time profiles for each subject from each treatment under each sequence. In the BE evaluation of pharmacokinetic crossover studies, the normality of the univariate response variable, e.g. log(AUC) 1 or log(Cmax), is often assumed in the literature without much evidence. Therefore, we investigate the distributional assumption of the normality of response variables, log(AUC) and log(Cmax), by simulating concentration-time profiles from two-stage pharmacokinetic models (commonly used in pharmacokinetic research) for a wide range of pharmacokinetic parameters and measurement error structures. Our simulations show that, under reasonable distributional assumptions on the pharmacokinetic parameters, log(AUC) has heavy tails and log(Cmax) is skewed. Sensitivity analyses are conducted to investigate how the distribution of the standardized log(AUC) (or the standardized log(Cmax)) for a large number of simulated subjects deviates from normality if distributions of errors in the pharmacokinetic model for plasma concentrations deviate from normality and if the plasma concentration can be described by different compartmental models.

Innovative polymer nanocomposite electrolytes: nanoscale manipulation of ion channels by functionalized graphenes.

PubMed

Choi, Bong Gill; Hong, Jinkee; Park, Young Chul; Jung, Doo Hwan; Hong, Won Hi; Hammond, Paula T; Park, Hoseok

2011-06-28

The chemistry and structure of ion channels within the polymer electrolytes are of prime importance for studying the transport properties of electrolytes as well as for developing high-performance electrochemical devices. Despite intensive efforts on the synthesis of polymer electrolytes, few studies have demonstrated enhanced target ion conduction while suppressing unfavorable ion or mass transport because the undesirable transport occurs through an identical pathway. Herein, we report an innovative, chemical strategy for the synthesis of polymer electrolytes whose ion-conducting channels are physically and chemically modulated by the ionic (not electronic) conductive, functionalized graphenes and for a fundamental understanding of ion and mass transport occurring in nanoscale ionic clusters. The functionalized graphenes controlled the state of water by means of nanoscale manipulation of the physical geometry and chemical functionality of ionic channels. Furthermore, the confinement of bound water within the reorganized nanochannels of composite membranes was confirmed by the enhanced proton conductivity at high temperature and the low activation energy for ionic conduction through a Grotthus-type mechanism. The selectively facilitated transport behavior of composite membranes such as high proton conductivity and low methanol crossover was attributed to the confined bound water, resulting in high-performance fuel cells.

A Randomized Crossover Trial of Dietary Sodium Restriction in Stage 3–4 CKD

PubMed Central

Padilla, Robin L.; Gillespie, Brenda W.; Heung, Michael; Hummel, Scott L.; Derebail, Vimal Kumar; Pitt, Bertram; Levin, Nathan W.; Zhu, Fansan; Abbas, Samer R.; Liu, Li; Kotanko, Peter; Klemmer, Philip

2017-01-01

Background and objectives Patients with chronic kidney disease (CKD) are often volume expanded and hypertensive. Few controlled studies have assessed the effects of a sodium-restricted diet (SRD) in CKD. Design, setting, participants, & measurements We conducted a randomized crossover trial to evaluate the effect of SRD (target <2 g sodium per day) versus usual diet on hydration status (by bioelectrical impedance spectroscopy) and blood pressure (BP) between May of 2009 and May of 2013. A total of 58 adults with stage 3–4 CKD were enrolled from two academic sites: University of Michigan (n=37) and University of North Carolina at Chapel Hill (n=21); 60% were men, 43% were diabetic, 93% were hypertensive, and mean age was 61 years. Participants followed SRD or usual diet for 4 weeks, followed by a 2-week washout period and a 4-week crossover phase. During the SRD, dieticians provided counseling every 2 weeks, using motivational interviewing techniques. Results Whole-body extracellular volume and calf intracellular volume decreased by 1.02 L (95% confidence interval [95% CI], −1.48 to −0.56; P<0.001) and −0.06 L (95% CI, −0.12 to −0.01; P=0.02), respectively, implying decreased fluid content on the SRD compared with usual diet. Significant reductions in urinary sodium (−57.3 mEq/24 h; 95% CI, −81.8 to −32.9), weight (−2.3 kg; 95% CI, −3.2 to −1.5), and 24-hour systolic BP (−10.8 mmHg; 95% CI, −17.0 to −4.6) were also observed (all P<0.01). Albumin-to-creatinine ratio did not change significantly and mean serum creatinine increased slightly (0.1 mg/dl; 95% CI, −0.01 to 0.2; P=0.06). No period or carryover effects were observed. Results were similar when analyzed from phase 1 only before crossover, although P values were modestly larger because of the loss of power. Conclusions In this randomized crossover trial, implementation of SRD in patients with CKD stage 3–4 resulted in clinically and statistically significant improvement in BP and hydration status. This simple dietary intervention merits a larger trial in CKD to evaluate effects on major clinical outcomes. PMID:28209636

Hydrogeologic controls on ground-water discharge to the Washington METRO subway tunnel near the Medical Center station and Crossover, Montgomery County, Maryland

USGS Publications Warehouse

Greene, Earl A.; Shapiro, Allen M.; LaMotte, Andrew E.

2004-01-01

Excessive water intrusion has been observed inside several of the Washington Metropolitan Area Transit Authority subway tunnels, with the worst leakage occurring along the Red Line tunnels and stations north of Dupont Circle in Washington, D.C. These tunnels were constructed in bedrock that contains permeable (water-bearing) joints and fractures. Excessive water leakage through the walls and water inside the underground facilities has damaged mechanical and electrical components in the tunnel, and has escalated the deterioration rate of the rail system. The U.S. Geological Survey and the Washington Metropolitan Area Transit Authority have worked cooperatively on a study from 200003 to describe and quantify the factors controlling ground-water flow into the Red Line subway tunnel near the Medical Center Station and Crossover in Montgomery County, Maryland. The Red Line near the Medical Center Station and Crossover passes through or beneath the gneissic Sykesville Formation and the biotite-hornblende tonalite member of the Georgetown Intrusive Suite, both of which contain numerous fractures. The mapped foliation and joints of the Sykesville Formation in the vicinity of the Medical Center Station and Crossover are generally orientated north-south. Fractures in the Sykesville Formation in outcrops appear to be poorly connected. In the biotite-hornblende tonalite member of the Georgetown Intrusive Suite, the general orientation of the mapped foliation and joints is east-west. In contrast to the fractures in the Sykesville Formation, the fractures in the Georgetown Intrusive Suite in outcrops appear to be more numerous and have a greater degree of connectivity. Fractures intersecting four bedrock wells near the Medical Center Station and Crossover that were drilled into the biotite-hornblende tonalite member of the Georgetown Intrusive Suite show an east-west orientation matching the foliation and joints shown on geologic maps. The excessive water intrusion at the Medical Center Station and Crossover could be the result of its location within the Georgetown Intrusive Suite. The abrupt changes in the mapped directions of ground-water flow based on the hydraulic heads at the contact between the Sykesville Formation and biotite-hornblende tonalite member of the Georgetown Intrusive Suite could also be the result of the change in fracturing between these two lithologies. Saprolite, a residual of soft, red/brown to gray clay from decomposed crystalline rock, overlies the bedrock and varies from about 20 to 55 feet thick, depending on location. On the basis of a slug test conducted in the lower part of the saprolite near the Medical Center Station and Crossover, transmissivity and storativity of the saprolite were estimated to be 10 feet squared per day and 10-6 , respectively. The transmissivity of fractures intersecting bedrock boreholes drilled in the biotite-hornblende tonalite member of the Georgetown Intrusive Suite varies over five orders of magnitude, from a maximum of approximately 10 feet squared per day to the detection limit of the in situ testing apparatus, which is approximately 10-4 feet squared per day. In general, the transmissivity of fractures intersecting the boreholes increases with depth. The low transmissivity of bedrock fractures in close proximity to the saprolite is likely to be caused by the fractures being filled with byproducts of rock weathering, resulting in reduced permeability. 2 Hydrogeologic Controls on Ground-Water Discharge to the Washington METRO Subway Tunnel The bulk transmissivity of the bedrock aquifer is approximately 3.7 feet squared per day, as determined from an aquifer test conducted by pumping a 240-foot-deep borehole and monitoring the drawdown over 3 days in the pumped borehole and several observation boreholes. In general, the hydraulic head decreases with depth in bedrock boreholes, indicating the potential for downward ground-water flow. Based on hydraulic head values mea

The effect of fish oil supplements on blood pressure.

PubMed Central

Lofgren, R P; Wilt, T J; Nichol, K L; Crespin, L; Pluhar, R; Eckfeldt, J

1993-01-01

We conducted a double-blind, placebo-controlled crossover study to determine the effects of fish oil supplementation on blood pressure in middle-aged men. Subjects were randomly assigned to consume either 20 g of fish oil or safflower oil for 12 weeks and then consume the other oil for an additional 12 weeks after a 4-week washout period. We found no significant changes from the pretreatment value in systolic or diastolic blood pressure with the use of fish oil supplements. In addition, there were no significant differences in the posttreatment blood pressures comparing the fish and safflower oil phases of the study. PMID:8427339

The effectiveness of topical colloidal silver in recalcitrant chronic rhinosinusitis: a randomized crossover control trial.

PubMed

Scott, John R; Krishnan, Rohin; Rotenberg, Brian W; Sowerby, Leigh J

2017-11-25

Recalcitrant chronic rhinosinusitis without polyposis (CRSsP) is a challenging condition to manage as traditional medical therapies and surgery fail to provide satisfactory clinical improvements. Colloidal silver (CS), a widely used naturopathic agent, has recently shown anti-biofilm properties both in vitro and within a rhinosinusitis animal model. To date, no trials involving humans have been published in world literature. The purpose of this study was to assess the efficacy of CS as a topical nasal spray in patients with refractory CRSsP. A prospective cohort study was conducted using a convenience sample of 20 randomized patients with crossover methodology, comparing nasal sprays with CS versus saline. Patients sprayed twice daily for six weeks with the first intervention and then switched to the second for the next six weeks, with measurements made at baseline and each time point. Primary outcomes were changes in SNOT-22 and Lund-Kennedy (LK) endoscopic scores. All analysis was non-parametric and was conducted using STATA 14. Twenty-two patients were enrolled in the study with 20 completing the entire protocol. Mean 6-week change in SNOT-22 scores were -2.8 and 1.0 for saline and CS, respectively (p = 0.373). Similarly, mean 6-week change in LK scores were -1.4 and -1.1 for saline and CS, respectively (p = 0.794). Significant period effects were observed with the SNOT-22 score between the randomized groups. No participants experienced negative health effects directly attributable to the administration of intranasal CS. Commercially available CS nasal spray did not demonstrate any meaningful subjective or objective improvements in patients with recalcitrant CRSsP. NCT02403479 . Registered on March 1, 2015.

Electrophysiological effects of desflurane in children with Wolff-Parkinson-White syndrome: a randomized crossover study.

PubMed

Hino, H; Oda, Y; Yoshida, Y; Suzuki, T; Shimada, M; Nishikawa, K

2018-02-01

We hypothesized that, compared with propofol, desflurane prolongs the antegrade accessory pathway effective refractory period (APERP) in children undergoing radiofrequency catheter ablation for Wolff-Parkinson-White (WPW) syndrome. In this randomized crossover study, children aged 4.1-16.1 years undergoing radiofrequency catheter ablation for WPW syndrome were randomly divided into four groups according to the concentration of desflurane and anesthetics used in the first and the second electrophysiological studies (EPS). After induction of general anesthesia with propofol and tracheal intubation, they received one of the following regimens: 0.5 minimum alveolar concentration (MAC) desflurane (first EPS) and propofol (second EPS) (Des0.5-Prop group, n = 8); propofol (first EPS) and 0.5 MAC desflurane (second EPS) (Prop-Des0.5 group, n = 9); 1 MAC desflurane (first EPS) and propofol (second EPS) (Des1.0-Prop group, n = 10); propofol (first EPS) and 1 MAC desflurane (second EPS) (Prop-Des1.0 group, n = 9). Radiofrequency catheter ablation was performed upon completion of EPS. Sample size was determined to detect a difference in the APERP. Desflurane at 1.0 MAC significantly prolonged the APERP compared with propofol, but did not affect the sinoatrial conduction time, atrio-His interval or atrioventricular node effective refractory period. Supraventricular tachycardia was induced in all children receiving propofol, but not induced in 1 and 4 children receiving 0.5 MAC and 1.0 MAC desflurane, respectively. Desflurane enhances the refractoriness and may block the electrical conduction of the atrioventricular accessory pathway, and is therefore not suitable for use in children undergoing radiofrequency catheter ablation for WPW syndrome. © 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Dynamics of Li+ ions in Li2O-TeO2-P2O5 glasses

NASA Astrophysics Data System (ADS)

Chatterjee, A.; Ghosh, A.

2018-04-01

In the present work we have studied transport properties of lithium ions in 0.3Li2O-0.7[xTeO2-(1-x)P2O5] glasses, where x=0.5, 0.6, 0.7. We have measured acconductivity for a wide range offrequency and temperature. The real part of the conductivity spectra has been analyzed by the power law in Almond-West formalism. The dc conductivity has been obtained from the complex impedance plots. We have found that dc conductivity increases and activation energy decreases on increase of TeO2 for a particular Li2O content. We have also found that the dc conductivity and crossover frequency obey Arrhenius relation. The time temperature superposition has been verified using the scaling formalism of the conductivity spectra. We have found that the conductivity isotherms scaled to a single master curve with suitable scaling parameters for a particular composition at different temperatures. However the scaling to a single master curve fails for different compositions at a particular temperature.

Spin Crossover and the Magnetic P- T Phase Diagram of Hematite at High Hydrostatic Pressures and Cryogenic Temperatures

NASA Astrophysics Data System (ADS)

Gavriliuk, A. G.; Struzhkin, V. V.; Mironovich, A. A.; Lyubutin, I. S.; Troyan, I. A.; Chow, P.; Xiao, Y.

2018-02-01

The magnetic properties of the α-Fe2O3 hematite at a high hydrostatic pressure have been studied by synchrotron Mössbauer spectroscopy (nuclear forward scattering (NFS)) on iron nuclei. Time-domain NFS spectra of hematite have been measured in a diamond anvil cell in the pressure range of 0-72 GPa and the temperature range of 36-300 K in order to study the magnetic properties at a phase transition near a critical pressure of 50 GPa. In addition, Raman spectra at room temperature have been studied in the pressure range of 0-77 GPa. Neon has been used as a pressure-transmitting medium. The appearance of an intermediate electronic state has been revealed at a pressure of 48 GPa. This state is probably related to the spin crossover in Fe3+ ions at their transition from the high-spin state (HS, S = 5/2) to a low-spin one (LS, S = 1/2). It has been found that the transient pressure range of the HS-LS crossover is extended from 48 to 55 GPa and is almost independent of the temperature. This surprising result differs fundamentally from other cases of the spin crossover in Fe3+ ions observed in other crystals based on iron oxides. The transition region of spin crossover appears because of thermal fluctuations between HS and LS states in the critical pressure range and is significantly narrowed at cooling because of the suppression of thermal excitations. The magnetic P- T phase diagram of α-Fe2O3 at high pressures and low temperatures in the spin crossover region has been constructed according to the results of measurements.

Exchangeability in the case-crossover design

PubMed Central

Mittleman, Murray A; Mostofsky, Elizabeth

2014-01-01

In cohort and case-control studies, confounding that arises as a result of differences in the distribution of determinants of the outcome between exposure groups leading to non-exchangeability are addressed by restriction, matching or with statistical models. In case-only studies, this issue is addressed by comparing each individual with his/herself. Although case-only designs use self-matching and only include individuals who develop the outcome of interest, issues of non-exchangeability are identical to those that arise in traditional case-control and cohort studies. In this review, we describe one type of case-only design, the case-crossover design, and discuss how the concept of exchangeability can be used to understand issues of confounding, carryover effects, period effects and selection bias in case-crossover studies. PMID:24756878

Ultrahigh Ionic Conduction in Water-Stable Close-Packed Metal-Carbonate Frameworks.

PubMed

Manna, Biplab; Desai, Aamod V; Illathvalappil, Rajith; Gupta, Kriti; Sen, Arunabha; Kurungot, Sreekumar; Ghosh, Sujit K

2017-08-21

Utilization of the robust metal-carbonate backbone in a series of water-stable, anionic frameworks has been harnessed for the function of highly efficient solid-state ion-conduction. The compact organization of hydrophilic guest ions facilitates water-assisted ion-conduction in all the compounds. The dense packing of the compounds imparts high ion-conducting ability and minimizes the possibility of fuel crossover, making this approach promising for design and development of compounds as potential components of energy devices. This work presents the first report of evaluating ion-conduction in a purely metal-carbonate framework, which exhibits high ion-conductivity on the order of 10 -2 S cm -1 along with very low activation energy, which is comparable to highly conducting well-known crystalline coordination polymers or commercialized organic polymers like Nafion.

Mood spillover and crossover among dual-earner couples: a cell phone event sampling study.

PubMed

Song, Zhaoli; Foo, Maw-Der; Uy, Marilyn A

2008-03-01

In this study, the authors examined affective experiences of dual-earner couples. More specifically, the authors explored how momentary moods can spill over between work and family and cross over from one spouse to another. Fifty couples used their cell phones to provide reports of their momentary moods over 8 consecutive days. Results show significant spillover and crossover effects for both positive and negative moods. Work orientation moderated negative mood spillover from work to home, and the presence of children in the family decreased negative mood crossover between spouses. Crossover was observed when spouses were physically together and when the time interval between the spouses' reports was short. With this study, the authors contribute to the work and family research by examining the nature of mood transfers among dual-earner couples, including the direction, valence, and moderators of these transfers across work and family domains. The authors also contribute to the event sampling methodology by introducing a new method of using cell phones to collect momentary data. Copyright 2008 APA

Advanced Clothing Studies

NASA Technical Reports Server (NTRS)

Orndoff, Evelyne; Poritz, Darwin

2014-01-01

All human space missions require significant logistical mass and volume that add an unprecedented burden on longduration missions beyond low-Earth orbit. For these missions with limited cleaning resources, a new wardrobe must be developed to reduce this logistical burden by reducing clothing mass and extending clothing wear. The present studies have been undertaken, for the first time, to measure length of wear and to assess the acceptance of such extended wear. Garments in these studies are commercially available exercise T-shirts and shorts, routine-wear T-shirts, and longsleeved pullover shirts. Fabric composition (cotton, polyester, light-weight, superfine Merino wool, modacrylic, cotton/rayon, polyester/Cocona, modacrylic/Xstatic, modacrylic/rayon, modacrylic/lyocell/aramid), construction (open knit, tight knit, open weave, tight weave), and finishing treatment (none, quaternary ammonium salt) are the independent variables. Eleven studies are reported here: five studies of exercise T-shirts, three of exercise shorts, two of routine wear Tshirts, and one of shirts used as sleep-wear. All studies are conducted in a climate-controlled environment, similar to a space vehicle's. For exercise clothing, study participants wear the garments during aerobic exercise. For routine wear clothing, study participants wear the T-shirts daily in an office or laboratory. Daily questionnaires collected data on ordinal preferences of nine sensory elements and on reason for retiring a used garment. Study 1 compares knitted cotton, polyester, and Merino exercise T-shirts (61 participants), study 2, knitted polyester, modacrylic, and polyester/Cocona exercise T-shirts (40 participants), study 3, cotton and polyester exercise shorts, knitted and woven (70 participants), all three using factorial experimental designs with and without a finishing treatment, conducted at the Johnson Space Center, sharing study participants. Study 4 compares knitted polyester and ZQ Merino exercise T-shirts, study 5, knitted ZQ Merino and modacrylic routine-wear T-shirts, with study 6 using only knitted polyester exercise shorts. No finishing treatment is used. Studies 4 and 5 use cross-over experimental designs, and all three studies were conducted aboard the ISS with six crew. Studies 4 and 6 were repeated on the ground with the same participants to learn if perception was affected microgravity. Study 7 is a longer-term, single-blind panel study of knitted routine-wear undershirts with at least 12 participants to assess tolerance to Merino by comparing it with a cotton/rayon blends, using a cross-over design, eliminating carryover effects with wash-out periods between shirts.

Orange pomace improves postprandial glycemic responses: an acute, randomized, placebo-controlled, double-blind, crossover trial in overweight men

USDA-ARS?s Scientific Manuscript database

Orange pomace (OP), a fiber-rich byproduct of juice production, has the potential for being formulated into a variety of food products. We hypothesized that OP would diminish postprandial glycemic responses to a high carbohydrate/fat breakfast and lunch. We conducted an acute, randomized, placebo-co...

PM₁₀ exposure and non-accidental mortality in Asian populations: a meta-analysis of time-series and case-crossover studies.

PubMed

Park, Hye Yin; Bae, Sanghyuk; Hong, Yun-Chul

2013-01-01

We investigated the association between particulate matter less than 10 µm in aerodynamic diameter (PM₁₀) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. Among the 819 published studies searched from PubMed and EMBASE using key words related to PM₁₀ exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per 10 µg/m³ increase of daily PM₁₀ from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per 10 µg/m³ increase of daily PM₁₀ for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. We found a significant positive association between PM₁₀ exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.

No correlation between germline mutation at repeat DNA and meiotic crossover in male mice exposed to X-rays or cisplatin.

PubMed

Barber, R; Plumb, M; Smith, A G; Cesar, C E; Boulton, E; Jeffreys, A J; Dubrova, Y E

2000-12-20

To test the hypothesis that mouse germline expanded simple tandem repeat (ESTR) mutations are associated with recombination events during spermatogenesis, crossover frequencies were compared with germline mutation rates at ESTR loci in male mice acutely exposed to 1Gy of X-rays or to 10mg/kg of the anticancer drug cisplatin. Ionising radiation resulted in a highly significant 2.7-3.6-fold increase in ESTR mutation rate in males mated 4, 5 and 6 weeks after exposure, but not 3 weeks after exposure. In contrast, irradiation had no effect on meiotic crossover frequencies assayed on six chromosomes using 25 polymorphic microsatellite loci spaced at approximately 20cM intervals and covering 421cM of the mouse genome. Paternal exposure to cisplatin did not affect either ESTR mutation rates or crossover frequencies, despite a report that cisplatin can increase crossover frequency in mice. Correlation analysis did not reveal any associations between the paternal ESTR mutation rate and crossover frequency in unexposed males and in those exposed to X-rays or cisplatin. This study does not, therefore, support the hypothesis that mutation induction at mouse ESTR loci results from a general genome-wide increase in meiotic recombination rate.

Work-family enrichment, work-family conflict, and marital satisfaction: a dyadic analysis.

PubMed

van Steenbergen, Elianne F; Kluwer, Esther S; Karney, Benjamin R

2014-04-01

This study was designed to examine whether spouses' work-to-family (WF) enrichment experiences account for their own and their partner's marital satisfaction, beyond the effects of WF conflict. Data were collected from both partners of 215 dual-earner couples with children. As hypothesized, structural equation modeling revealed that WF enrichment experiences accounted for variance in individuals' marital satisfaction, over and above WF conflict. In line with our predictions, this positive link between individuals' WF enrichment and their marital satisfaction was mediated by more positive marital behavior, and more positive perceptions of the partner's behavior. Furthermore, evidence for crossover was found. Husbands who experienced more WF enrichment were found to show more marital positivity (according to their wives), which related to increased marital satisfaction in their wives. No evidence of such a crossover effect from wives to husbands was found. The current findings not only highlight the added value of studying positive spillover and crossover effects of work into the marriage, but also suggest that positive spillover and crossover effects on marital satisfaction might be stronger than negative spillover and crossover are. These results imply that organizational initiatives of increasing job enrichment may make employees' marital life happier and can contribute to a happy, healthy, and high-performing workforce.

Assessing the impact of electrolyte conductivity and viscosity on the reactor cost and pressure drop of redox-active polymer flow batteries

NASA Astrophysics Data System (ADS)

Iyer, Vinay A.; Schuh, Jonathon K.; Montoto, Elena C.; Pavan Nemani, V.; Qian, Shaoyi; Nagarjuna, Gavvalapalli; Rodríguez-López, Joaquín; Ewoldt, Randy H.; Smith, Kyle C.

2017-09-01

Redox-active small molecules, used traditionally in redox flow batteries (RFBs), are susceptible to crossover and require expensive ion exchange membranes (IEMs) to achieve long lifetimes. Redox-active polymer (RAP) solutions show promise as candidate electrolytes to mitigate crossover through size-exclusion, enabling the use of porous separators instead of IEMs. Here, poly(vinylbenzyl ethyl viologen) is studied as a surrogate RAP for RFBs. For oxidized RAPs, ionic conductivity varies weakly between 1.6 and 2.1 S m-1 for RAP concentrations of 0.13-1.27 mol kg-1 (monomeric repeat unit per kg solvent) and 0.32 mol kg-1 LiBF4 with a minor increase upon reduction. In contrast, viscosity varies between 1.8 and 184.0 mPa s over the same concentration range with weakly shear-thinning rheology independent of oxidation state. Techno-economic analysis is used to quantify reactor cost as a function of electrolyte transport properties for RAP concentrations of 0.13-1.27 mol kg-1, assuming a hypothetical 3V cell and facile kinetics. Among these concentrations, reactor cost is minimized over a current density range of 600-1000 A m-2 with minimum reactor cost between 11-17 per kWh, and pumping pressures below 10 kPa. The predicted low reactor cost of RAP RFBs is enabled by sustained ionic mobility in spite of the high viscosity of concentrated RAP solutions.

The influence of transcutaneous electrical nerve stimulation parameters on the level of pain perceived by participants with painful diabetic neuropathy: A crossover study.

PubMed

Upton, Gabrielle A; Tinley, Paul; Al-Aubaidy, Hayder; Crawford, Rachel

This pilot study aimed to investigate and compare the perceived pain relief effectiveness of two different modes of TENS in people with painful diabetic neuropathy (PDN). A cross-over study was conducted at Charles Sturt University, Orange. Five participants with PDN were assessed with a McGill Pain Questionnaire before and after each of the two TENS treatments. Participants were randomly allocated to Traditional TENS (80Hz, 200ms) or Acupuncture-like TENS (2Hz, 200ms) and the treatments were applied daily for 30min over ten days. Following a seven day washout period, the alternate mode of TENS was carried out using the same method. Wilcoxon Signed Rank tests were used to statistically analyse the results. All five participants reported personally meaningful pain relief during one or both of the TENS treatments. The Wilcoxon signed rank testing showed no statistical significance, p=1, likely due to the small sample size. Acupuncture-like TENS had a large effect size (z=-1.625, r=0.514), whilst Traditional TENS produced a medium effect size (z=-1.214, r=0.384). No adverse effects were reported. Acupuncture-like TENS may be more effective for PDN than traditional TENS. A larger scale replication of this pilot study is warranted. Copyright © 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Trapped ion system for sympathetic cooling and non-equilibrium dynamics

NASA Astrophysics Data System (ADS)

Doret, Charlie; Jubin, Sierra; Stevenson, Sarah

2017-04-01

Atomic systems are superbly suited to the study of non-equilibrium dynamics. These systems' exquisite isolation from environmental perturbations leads to long relaxation times that enable exploration of far-from-equilibrium phenomena. We present progress towards trapping chains of multiple co-trapped calcium isotopes geared towards measuring thermal equilibration and sympathetic cooling rates. We also discuss plans for future experiments in non-equilibrium statistical mechanics, including exploration of the quantum-to-classical crossover between ballistic transport and diffusive, Fourier's Law conduction. This work is supported by Cottrell College Science Award from the Research Corporation for Science Advancement and by Williams College.

Control of Meiotic Crossovers: From Double-Strand Break Formation to Designation

PubMed Central

Gray, Stephen

2017-01-01

Meiosis, the mechanism of creating haploid gametes, is a complex cellular process observed across sexually reproducing organisms. Fundamental to meiosis is the process of homologous recombination, whereby DNA double-strand breaks are introduced into the genome and are subsequently repaired to generate either noncrossovers or crossovers. Although homologous recombination is essential for chromosome pairing during prophase I, the resulting crossovers are critical for maintaining homolog interactions and enabling accurate segregation at the first meiotic division. Thus, the placement, timing, and frequency of crossover formation must be exquisitely controlled. In this review, we discuss the proteins involved in crossover formation, the process of their formation and designation, and the rules governing crossovers, all within the context of the important landmarks of prophase I. We draw together crossover designation data across organisms, analyze their evolutionary divergence, and propose a universal model for crossover regulation. PMID:27648641

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

NASA Astrophysics Data System (ADS)

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

2018-04-01

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

Academic Crossover Study, University of Hawaii Community Colleges, Fall 1999.

ERIC Educational Resources Information Center

Hawaii Univ., Honolulu. Office of the Chancellor for Community Colleges.

The academic crossover study was developed to answer two questions: (1) What is the course-taking pattern of the different groups of academic majors? (e.g. what is proportion of academic load taken outside the major); and (2) What is the client-serving pattern of the different subject disciplines? (e.g. what are the groups of students served by…

Chorionic gonadotropin in weight control. A double-blind crossover study.

PubMed

Young, R L; Fuchs, R J; Woltjen, M J

1976-11-29

Two hundred two patients participated in a double-blind random cross-over study of the effectiveness of human chorionic gonadotropin (HCG) vs placebo in a wieght reduction program. Serial measurements were made of weight, skin-fold thickness, dropout rates, reasons for dropping out, and patient subjective response. There was no statistically significant difference between those receiving HCG vs placebo during any phase of this study (P greater than .1).

Increased calcium absorption from synthetic stable amorphous calcium carbonate: double-blind randomized crossover clinical trial in postmenopausal women.

PubMed

Vaisman, Nachum; Shaltiel, Galit; Daniely, Michal; Meiron, Oren E; Shechter, Assaf; Abrams, Steven A; Niv, Eva; Shapira, Yami; Sagi, Amir

2014-10-01

Calcium supplementation is a widely recognized strategy for achieving adequate calcium intake. We designed this blinded, randomized, crossover interventional trial to compare the bioavailability of a new stable synthetic amorphous calcium carbonate (ACC) with that of crystalline calcium carbonate (CCC) using the dual stable isotope technique. The study was conducted in the Unit of Clinical Nutrition, Tel Aviv Sourasky Medical Center, Israel. The study population included 15 early postmenopausal women aged 54.9 ± 2.8 (mean ± SD) years with no history of major medical illness or metabolic bone disorder, excess calcium intake, or vitamin D deficiency. Standardized breakfast was followed by randomly provided CCC or ACC capsules containing 192 mg elemental calcium labeled with 44Ca at intervals of at least 3 weeks. After swallowing the capsules, intravenous CaCl2 labeled with 42Ca on was administered on each occasion. Fractional calcium absorption (FCA) of ACC and CCC was calculated from the 24-hour urine collection following calcium administration. The results indicated that FCA of ACC was doubled (± 0.96 SD) on average compared to that of CCC (p < 0.02). The higher absorption of the synthetic stable ACC may serve as a more efficacious way of calcium supplementation. © 2014 American Society for Bone and Mineral Research.

Alcohol Abuse and Suicide Attempt in Iran: A Case-Crossover Study

PubMed Central

Ghanbari, Behrooz; Malakouti, Seyed Kazem; Nojomi, Marzieh; Leo, Diego De; Saeed, Khalid

2016-01-01

Alcohol use and its disorders are associated with increased risk of suicidal behaviors Research has shown that 6-8% of those who use alcohol have a history of suicide attempt. Given the prohibition of alcohol use legally, the increased alcohol consumption, and the lack of strong evidence in favor of its use associated with suicide in Iran, this study was conducted to determine the link between suicide attempt and alcohol abuse. The case-crossover method was used in this research. Out of 305 referrals to the emergency room due to a suicide attempt, 100 reported drinking alcohol up to six hours before their attempt. Paired Matching and Usual Frequency were employed to analyze the data with STATA 12.0. The probability of attempting suicide up to six hours after drinking alcohol appeared increased by 27 times (95% CI: 8.1-60.4). Separate analysis for each of these hours from the first to the sixth hour after alcohol use was also performed. Fifty percent of attempted suicides happened one hour after alcohol use. Relative risk for the first and second hour was 10% and 5% respectively. Alcohol use is a strong proximal risk factor for attempted suicide among Iranian subjects. Prevention of alcohol use should be considered in setting up of the national Suicide attempt prevention program. PMID:26925903

Association of cerebrovascular events with antidepressant use: a case-crossover study.

PubMed

Wu, Chi-Shin; Wang, Sheng-Chang; Cheng, Yu-Cheng; Gau, Susan Shur-Fen

2011-05-01

The authors sought to assess the risk of cerebrovascular events associated with use of antidepressant medications. The authors conducted a case-crossover study of 24,214 patients with stroke enrolled in the National Health Insurance Research Database in Taiwan from 1998 to 2007. The authors compared the rates of antidepressant use during case and control time windows of 7, 14, and 28 days. Adjustments were made for time-dependent variables, such as health system utilization and proposed confounding medications. Stratified analyses were performed for valuing the interaction between the stroke risk of antidepressant use and age, sex, presence of mood disorder, stroke type, severity of chronic illness, and duration of antidepressant treatment. A conditional logistic regression model was used to determine the odds of antidepressant use during case time windows. The adjusted odds ratio of stroke risk with antidepressant exposure was 1.48 (95% confidence interval=1.37-1.59) using 14-day time windows. Stroke risk was negatively associated with the number of antidepressant prescriptions reported. Use of antidepressants with high inhibition of the serotonin transporter was associated with a greater risk of stroke than use of other types of antidepressants. These findings suggest that antidepressant use may be associated with an increased risk of stroke. However, the underlying mechanisms remain unclear.

Electrical Conductivity of HgTe at High Temperatures

NASA Technical Reports Server (NTRS)

Li, C.; Lehoczky, S. L.; Su, C.-H.; Scripa, R. N.

2004-01-01

The electrical conductivity of HgTe was measured using a rotating magnetic field method from 300 K to the melting point (943 K). A microscopic theory for electrical conduction was used to calculate the expected temperature dependence of the HgTe conductivity. A comparison between the measured and calculated conductivities was used to obtain the estimates of the temperature dependence of Gamma(sub 6)-Gamma(sub 8) energy gap from 300 K to 943 K. The estimated temperature coefficient for the energy gap was comparable to the previous results at lower temperatures (less than or equal to 300 K). A rapid increase in the conductivity just above 300 K and a subsequent decrease at 500 K is attributed to band crossover effects. This paper describes the experimental approach and some of the theoretical calculation details.

A two-step spin crossover mononuclear iron(II) complex with a [HS-LS-LS] intermediate phase.

PubMed

Bonnet, Sylvestre; Siegler, Maxime A; Costa, José Sánchez; Molnár, Gábor; Bousseksou, Azzedine; Spek, Anthony L; Gamez, Patrick; Reedijk, Jan

2008-11-21

The two-step spin crossover of a new mononuclear iron(ii) complex is studied by magnetic, crystallographic and calorimetric methods revealing two successive first-order phase transitions and an ordered intermediate phase built by the repetition of the unprecedented [HS-LS-LS] motif.

Tramadol use and the risk of hospitalization for hypoglycemia in patients with noncancer pain.

PubMed

Fournier, Jean-Pascal; Azoulay, Laurent; Yin, Hui; Montastruc, Jean-Louis; Suissa, Samy

2015-02-01

Tramadol is a weak opioid analgesic whose use has increased rapidly, and it has been associated with adverse events of hypoglycemia. To assess whether tramadol use, when compared with codeine use, is associated with an increased risk of hospitalization for hypoglycemia. A nested case-control analysis was conducted within the United Kingdom Clinical Practice Research Datalink linked to the Hospital Episodes Statistics database of all patients newly treated with tramadol or codeine for noncancer pain between 1998 and 2012. Cohort and case-crossover analyses were also conducted to assess consistency of the results. Cases of hospitalization for hypoglycemia were matched with up to 10 controls on age, sex, and duration of follow-up. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated comparing use of tramadol with codeine. A cohort analysis, with high-dimensional propensity score-adjusted hazard ratios (HRs) and 95% CIs, was performed comparing tramadol with codeine in the first 30 days after treatment initiation. Finally, a case-crossover analysis was also performed, in which exposure to tramadol in a 30-day risk period immediately before the hospitalization for hypoglycemia was compared with 11 consecutive 30-day control periods. Odds ratios and 95% CIs were estimated using conditional logistic regression analysis. The cohort included 334,034 patients, of whom 1105 were hospitalized for hypoglycemia during follow-up (incidence, 0.7 per 1000 per year) and matched to 11,019 controls. Compared with codeine, tramadol use was associated with an increased risk of hospitalization for hypoglycemia (OR, 1.52 [95% CI, 1.09-2.10]), particularly elevated in the first 30 days of use (OR, 2.61 [95% CI, 1.61-4.23]). This 30-day increased risk was confirmed in the cohort (HR, 3.60 [95% CI, 1.56-8.34]) and case-crossover analyses (OR, 3.80 [95% CI, 2.64-5.47]). The initiation of tramadol therapy is associated with an increased risk of hypoglycemia requiring hospitalization. Additional studies are needed to confirm this rare but potentially fatal adverse event.

Effects of Ayurvedic Oil-Dripping Treatment with Sesame Oil vs. with Warm Water on Sleep: A Randomized Single-Blinded Crossover Pilot Study

PubMed Central

Yorifuji, Takashi; Tsuda, Toshihide; Doi, Hiroyuki

2016-01-01

Abstract Objectives: Ayurvedic oil-dripping treatment (Shirodhara) is often used for treating sleep problems. However, few properly designed studies have been conducted, and the quantitative effect of Shirodhara is unclear. This study sought to quantitatively evaluate the effect of sesame oil Shirodhara (SOS) against warm water Shirodhara (WWS) on improving sleep quality and quality of life (QOL) among persons reporting sleep problems. Methods: This randomized, single-blinded, crossover study recruited 20 participants. Each participant received seven 30-minute sessions within 2 weeks with either liquid. The washout period was at least 2 months. The Shirodhara procedure was conducted by a robotic oil-drip system. The outcomes were assessed by the Pittsburgh Sleep Quality Index (PSQI) for sleep quality, Epworth Sleepiness Scale (ESS) for daytime sleepiness, World Health Organization Quality of Life 26 (WHO-QOL26) for QOL, and a sleep monitor instrument for objective sleep measures. Changes between baseline and follow-up periods were compared between the two types of Shirodhara. Analysis was performed with generalized estimating equations. Results: Of 20 participants, 15 completed the study. SOS improved sleep quality, as measured by PSQI. The SOS score was 1.83 points lower (95% confidence interval [CI], −3.37 to −0.30) at 2-week follow-up and 1.73 points lower (95% CI, −3.84 to 0.38) than WWS at 6-week follow-up. Although marginally significant, SOS also improved QOL by 0.22 points at 2-week follow-up and 0.19 points at 6-week follow-up compared with WWS. After SOS, no beneficial effects were observed on daytime sleepiness or objective sleep measures. Conclusions: This pilot study demonstrated that SOS may be a safe potential treatment to improve sleep quality and QOL in persons with sleep problems. PMID:26669255

An investigation of the safety and pharmacokinetics of the novel TRPV1 antagonist XEN-D0501 in healthy subjects

PubMed Central

Round, Patrick; Priestley, Anthony; Robinson, Jan

2011-01-01

AIMS XEN-D0501, a novel TRPV1 antagonist, is being developed to treat overactive bladder. This study investigated the safety and pharmacokinetics of repeat-dose XEN-D0501 in healthy subjects. METHODS The study was conducted in two parts. Part 1 was a double-blind, randomized, placebo-controlled, two-way crossover study in three cohorts of 12 young male subjects. Each subject received XEN-D0501 and placebo (in random order) twice daily for 13 days, with a final single dose on day 14. Doses of 1, 2.5 and 5 mg XEN-D0501 were investigated. Part 2 was an open-label, randomized, two-way crossover study in male and female subjects (45 to 65 years). Subjects received single doses of 5 mg XEN-D0501 under fasted and fed conditions in random order. Blood sampling and safety assessments were conducted throughout the study. RESULTS XEN-D0501 was rapidly absorbed (tmax generally 0.5–4 h post dose). XEN-D0501 exposure increased less than proportionally to dose over the range studied and exhibited minimal accumulation with twice daily dosing. Food had no clinically relevant effects on the pharmacokinetics of XEN-D0501. There were no severe or serious adverse events and all doses were well tolerated. A dose-related increase in body temperature was seen with XEN-D0501 which attenuated over time. Differences from placebo in mean maximum core body temperatures were 0.22°C, 0.5°C and 0.74°C following 1 mg, 2.5 mg and 5 mg twice daily XEN-D0501. The observed increase in body temperature was not considered to be of clinical concern. CONCLUSIONS XEN-D0501 appeared safe and well tolerated at doses up to 5 mg twice daily for 14 days in healthy subjects. PMID:21676011

Core structure of two-dimensional Fermi gas vortices in the BEC-BCS crossover region

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

Madeira, Lucas; Gandolfi, Stefano; Schmidt, Kevin E.

2017-05-02

We report T = 0 diffusion Monte Carlo results for the ground-state and vortex excitation of unpolarized spin-1/2 fermions in a two-dimensional disk. We investigate how vortex core structure properties behave over the BEC-BCS crossover. We calculate the vortex excitation energy, density pro les, and vortex core properties related to the current. We nd a density suppression at the vortex core on the BCS side of the crossover and a depleted core on the BEC limit. Size-effect dependencies in the disk geometry were carefully studied.

Solution-Based Electro-Orientation Spectroscopy (EOS) for Contactless Measurement of Semiconductor Nanowires

NASA Astrophysics Data System (ADS)

Yuan, Wuhan; Mohabir, Amar; Tutuncuoglu, Gozde; Filler, Michael; Feldman, Leonard; Shan, Jerry

2017-11-01

Solution-based, contactless methods for determining the electrical conductivity of nanowires and nanotubes have unique advantages over conventional techniques in terms of high throughput and compatibility with further solution-based processing and assembly methods. Here, we describe the solution-based electro-orientation spectroscopy (EOS) method, in which nanowire conductivity is measured from the AC-electric-field-induced alignment rate of the nanowire in a suspending fluid. The particle conductivity is determined from the measured crossover frequency between conductivity-dominated, low-frequency alignment to the permittivity-dominated, high-frequency regime. We discuss the extension of the EOS measurement range by an order-of-magnitude, taking advantage of the high dielectric constant of deionized water. With water and other fluids, we demonstrate that EOS can quantitatively characterize the electrical conductivities of nanowires over a 7-order-of-magnitude range, 10-5 to 102 S/m. We highlight the efficiency and utility of EOS for nanomaterial characterization by statistically characterizing the variability of semiconductor nanowires of the same nominal composition, and studying the connection between synthesis parameters and properties. NSF CBET-1604931.

Higher-Than-Ballistic Conduction in Viscous Electron Fluids

NASA Astrophysics Data System (ADS)

Levitov, Leonid

Strongly interacting electrons can move in a neatly coordinated way, reminiscent of the movement of viscous fluids. This talk will argue that in viscous flows interactions facilitate transport, allowing conductance to exceed the fundamental Sharvin-Landauer quantum-ballistic limit. The effect is particularly striking for the flow through a viscous point contact, a constriction exhibiting the quantum-mechanical ballistic transport at T = 0 but governed by electron hydrodynamics at elevated temperatures. Conductance grows as a square of the constriction width, i.e. faster than the linear width dependence for noninteracting fermions. The crossover between the ballistic and viscous regimes occurs when the mean free path for e-e collisions becomes comparable to the constriction width. Further, we will discuss the negative nonlocal response, a signature effect of viscous transport. This response exhibits an interesting nonmonotonic behavior vs. T at the viscous-to-balistic transition. The response is negative but small in the highly viscous regime at elevated temperatures. The value grows as the temperature is lowered and the system becomes less viscous, reaching the most negative values in the crossover region where the mean free path is comparable to the distance between contacts. Subsequently, it reverses sign at even lower temperatures, becoming positive as the system enters the ballistic regime. This peculiar behavior provides a clear signature of the ballistic-to-viscous transition and enables a direct measurement of the electron-electron collision mean free path.

A Randomized, Double-Blind, Crossover Comparison of MK-0929 and Placebo in the Treatment of Adults with ADHD

ERIC Educational Resources Information Center

Rivkin, Anna; Alexander, Robert C.; Knighton, Jennifer; Hutson, Pete H.; Wang, Xiaojing J.; Snavely, Duane B.; Rosah, Thomas; Watt, Alan P.; Reimherr, Fred W.; Adler, Lenard A.

2012-01-01

Objective: Preclinical models, receptor localization, and genetic linkage data support the role of D4 receptors in the etiology of ADHD. This proof-of-concept study was designed to evaluate MK-0929, a selective D4 receptor antagonist as treatment for adult ADHD. Method: A randomized, double-blind, placebo-controlled, crossover study was conducted…

Challenging Fiction: Exploring Meaning-Making Processes in the Crossover between Social Media and Drama in Education

ERIC Educational Resources Information Center

Knudsen, Kristian Nødtvedt

2018-01-01

The aim of this study was to explore how meaning-making activity can be expressed and shaped in the crossover between drama in education and social media. This study concerns the use of empirical material from an educational drama project called #iLive, which was designed and implemented, on four different occasions with a total of 89 students…

Analysis of nonlocal phonon thermal conductivity simulations showing the ballistic to diffusive crossover

NASA Astrophysics Data System (ADS)

Allen, Philip B.

2018-04-01

Simulations [e.g., X. W. Zhou et al., Phys. Rev. B 79, 115201 (2009), 10.1103/PhysRevB.79.115201] show nonlocal effects of the ballistic/diffusive crossover. The local temperature has nonlinear spatial variation not contained in the local Fourier law j ⃗(r ⃗) =-κ ∇ ⃗T (r ⃗) . The heat current j ⃗(r ⃗) depends not just on the local temperature gradient ∇ ⃗T (r ⃗) but also on temperatures at points r⃗' within phonon mean free paths, which can be micrometers long. This paper uses the Peierls-Boltzmann transport theory in nonlocal form to analyze the spatial variation Δ T (r ⃗) . The relaxation-time approximation (RTA) is used because the full solution is very challenging. Improved methods of extrapolation to obtain the bulk thermal conductivity κ are proposed. Callaway invented an approximate method of correcting RTA for the q ⃗ (phonon wave vector or crystal momentum) conservation of N (Normal as opposed to Umklapp) anharmonic collisions. This method is generalized to the nonlocal case where κ (k ⃗) depends on the wave vector of the current j ⃗(k ⃗) and temperature gradient i k ⃗Δ T (k ⃗) .

Cluster randomised crossover trials with binary data and unbalanced cluster sizes: application to studies of near-universal interventions in intensive care.

PubMed

Forbes, Andrew B; Akram, Muhammad; Pilcher, David; Cooper, Jamie; Bellomo, Rinaldo

2015-02-01

Cluster randomised crossover trials have been utilised in recent years in the health and social sciences. Methods for analysis have been proposed; however, for binary outcomes, these have received little assessment of their appropriateness. In addition, methods for determination of sample size are currently limited to balanced cluster sizes both between clusters and between periods within clusters. This article aims to extend this work to unbalanced situations and to evaluate the properties of a variety of methods for analysis of binary data, with a particular focus on the setting of potential trials of near-universal interventions in intensive care to reduce in-hospital mortality. We derive a formula for sample size estimation for unbalanced cluster sizes, and apply it to the intensive care setting to demonstrate the utility of the cluster crossover design. We conduct a numerical simulation of the design in the intensive care setting and for more general configurations, and we assess the performance of three cluster summary estimators and an individual-data estimator based on binomial-identity-link regression. For settings similar to the intensive care scenario involving large cluster sizes and small intra-cluster correlations, the sample size formulae developed and analysis methods investigated are found to be appropriate, with the unweighted cluster summary method performing well relative to the more optimal but more complex inverse-variance weighted method. More generally, we find that the unweighted and cluster-size-weighted summary methods perform well, with the relative efficiency of each largely determined systematically from the study design parameters. Performance of individual-data regression is adequate with small cluster sizes but becomes inefficient for large, unbalanced cluster sizes. When outcome prevalences are 6% or less and the within-cluster-within-period correlation is 0.05 or larger, all methods display sub-nominal confidence interval coverage, with the less prevalent the outcome the worse the coverage. As with all simulation studies, conclusions are limited to the configurations studied. We confined attention to detecting intervention effects on an absolute risk scale using marginal models and did not explore properties of binary random effects models. Cluster crossover designs with binary outcomes can be analysed using simple cluster summary methods, and sample size in unbalanced cluster size settings can be determined using relatively straightforward formulae. However, caution needs to be applied in situations with low prevalence outcomes and moderate to high intra-cluster correlations. © The Author(s) 2014.

A compartmentalized signaling network mediates crossover control in meiosis

PubMed Central

Zhang, Liangyu; Köhler, Simone; Rillo-Bohn, Regina

2018-01-01

During meiosis, each pair of homologous chromosomes typically undergoes at least one crossover (crossover assurance), but these exchanges are strictly limited in number and widely spaced along chromosomes (crossover interference). The molecular basis for this chromosome-wide regulation remains mysterious. A family of meiotic RING finger proteins has been implicated in crossover regulation across eukaryotes. Caenorhabditis elegans expresses four such proteins, of which one (ZHP-3) is known to be required for crossovers. Here we investigate the functions of ZHP-1, ZHP-2, and ZHP-4. We find that all four ZHP proteins, like their homologs in other species, localize to the synaptonemal complex, an unusual, liquid crystalline compartment that assembles between paired homologs. Together they promote accumulation of pro-crossover factors, including ZHP-3 and ZHP-4, at a single recombination intermediate, thereby patterning exchanges along paired chromosomes. These proteins also act at the top of a hierarchical, symmetry-breaking process that enables crossovers to direct accurate chromosome segregation. PMID:29521627

The spatial regulation of meiotic recombination hotspots: are all DSB hotspots crossover hotspots?

PubMed

Serrentino, Maria-Elisabetta; Borde, Valérie

2012-07-15

A key step for the success of meiosis is programmed homologous recombination, during which crossovers, or exchange of chromosome arms, take place. Crossovers increase genetic diversity but their main function is to ensure accurate chromosome segregation. Defects in crossover number and position produce aneuploidies that represent the main cause of miscarriages and chromosomal abnormalities such as Down's syndrome. Recombination is initiated by the formation of programmed double strand breaks (DSBs), which occur preferentially at places called DSB hotspots. Among all DSBs generated, only a small fraction is repaired by crossover, the other being repaired by other homologous recombination pathways. Crossover maps have been generated in a number of organisms, defining crossover hotspots. With the availability of genome-wide maps of DSBs as well as the ability to measure genetically the repair outcome at several hotspots, it is becoming more and more clear that not all DSB hotspots behave the same for crossover formation, suggesting that chromosomal features distinguish different types of hotspots. Copyright © 2012. Published by Elsevier Inc.

Using Electrospinning-Based Carbon Nanofiber Webs for Methanol Crossover Control in Passive Direct Methanol Fuel Cells.

PubMed

Yuan, Wei; Fang, Guoyun; Li, Zongtao; Chen, Yonghui; Tang, Yong

2018-01-04

Methanol crossover (MCO) significantly affects the performance of a direct methanol fuel cell (DMFC). In order to reduce its effect, this study presents in-house carbon nanofiber webs (CNWs) used as a porous methanol barrier for MCO control in a passive DMFC. The CNW is made from polyacrylonitrile (PAN) by using electrospinning and heat treatment. The impacts of PAN concentration and carbonizing temperature on the material properties are considered. The concentration of PAN has a great effect on the micro structures of the CNWs since a higher concentration of PAN leads to a larger nanofiber diameter and lower porosity. A higher carbonizing temperature helps promote the sample conductivity. The use of CNWs has twofold effects on the cell performance. It helps significantly enhance the cell performance, especially at a low methanol concentration due to its balanced effect on reactant and product management. There is an increase in peak power density of up to 53.54% when the CNW is used, in contrast with the conventional DMFC at 2 mol/L. The dynamic and constant-load performances of the fuel cell based on CNWs are also investigated in this work.

Using Electrospinning-Based Carbon Nanofiber Webs for Methanol Crossover Control in Passive Direct Methanol Fuel Cells

PubMed Central

Fang, Guoyun; Chen, Yonghui; Tang, Yong

2018-01-01

Methanol crossover (MCO) significantly affects the performance of a direct methanol fuel cell (DMFC). In order to reduce its effect, this study presents in-house carbon nanofiber webs (CNWs) used as a porous methanol barrier for MCO control in a passive DMFC. The CNW is made from polyacrylonitrile (PAN) by using electrospinning and heat treatment. The impacts of PAN concentration and carbonizing temperature on the material properties are considered. The concentration of PAN has a great effect on the micro structures of the CNWs since a higher concentration of PAN leads to a larger nanofiber diameter and lower porosity. A higher carbonizing temperature helps promote the sample conductivity. The use of CNWs has twofold effects on the cell performance. It helps significantly enhance the cell performance, especially at a low methanol concentration due to its balanced effect on reactant and product management. There is an increase in peak power density of up to 53.54% when the CNW is used, in contrast with the conventional DMFC at 2 mol/L. The dynamic and constant-load performances of the fuel cell based on CNWs are also investigated in this work. PMID:29300368

Sample size determination for equivalence assessment with multiple endpoints.

PubMed

Sun, Anna; Dong, Xiaoyu; Tsong, Yi

2014-01-01

Equivalence assessment between a reference and test treatment is often conducted by two one-sided tests (TOST). The corresponding power function and sample size determination can be derived from a joint distribution of the sample mean and sample variance. When an equivalence trial is designed with multiple endpoints, it often involves several sets of two one-sided tests. A naive approach for sample size determination in this case would select the largest sample size required for each endpoint. However, such a method ignores the correlation among endpoints. With the objective to reject all endpoints and when the endpoints are uncorrelated, the power function is the production of all power functions for individual endpoints. With correlated endpoints, the sample size and power should be adjusted for such a correlation. In this article, we propose the exact power function for the equivalence test with multiple endpoints adjusted for correlation under both crossover and parallel designs. We further discuss the differences in sample size for the naive method without and with correlation adjusted methods and illustrate with an in vivo bioequivalence crossover study with area under the curve (AUC) and maximum concentration (Cmax) as the two endpoints.

A crossover trial evaluating an educational-behavioural joint protection programme for people with rheumatoid arthritis.

PubMed

Hammond, A; Lincoln, N; Sutcliffe, L

1999-05-01

Joint protection (JP) is a self-management technique widely taught to people with rheumatoid arthritis (RA). JP education aims to enable people with RA to reduce pain, inflammation, joint stress and reduce risks of deformity through using assistive devices and alternative movement patterns of affected joints to perform everyday activities. Previous studies evaluating JP education methods common in the UK have identified JP adherence is poor. A group education programme was developed using the Health Belief Model and Self-efficacy Theory. Strategies used to maximise JP adherence included goal-setting, contracting, modelling, homework programmes, motor learning theory, recall enhancing methods and mental practice. A crossover trial (n = 35) was conducted. Adherence with JP was measured using an objective observational test (the Joint Protection Behaviour Assessment). Significant improvements in use of JP were recorded at 12 and 24 weeks post-education (P < 0.01). No significant changes in measures of pain, functional disability, grip strength, self-efficacy or helplessness occurred post-education, although this may have been due to the small sample size recruited. In conclusion, JP adherence can be facilitated through the use of educational-behavioural strategies, suggesting this approach should be more widely adopted in clinical practice.

Site-specific mouth rinsing can improve oral odor by altering bacterial counts. Blind crossover clinical study.

PubMed

Alqumber, Mohammed A; Arafa, Khaled A

2014-11-01

To determine whether site-specific mouth rinsing with oral disinfectants can improve oral odor beyond the traditional panoral mouth disinfection with mouth rinses by targeting specifically oral malodor implicated anaerobic bacteria. Twenty healthy fasting subjects volunteered for a blinded prospective, descriptive correlational crossover cross-section clinical trial conducted during the month of Ramadan between July and August 2013 in Albaha province in Saudi Arabia involving the application of Listerine Cool Mint mouth rinse by either the traditional panoral rinsing method, or a site-specific disinfection method targeting the subgingival and supragingival plaque and the posterior third of the tongue dorsum, while avoiding the remaining locations within the oral cavity. The viable anaerobic and aerobic bacterial counts, volatile sulfur compounds (VSCs) levels, organoleptic assessment of oral odor, and the tongue-coating index were compared at baseline, one, 5, and 9 hours after the treatment. The site-specific disinfection method reduced the VSCs and anaerobic bacterial loads while keeping the aerobic bacterial numbers higher than the traditional panoral rinsing method. Site-specific disinfection can more effectively maintain a healthy oral cavity by predominantly disinfecting the niches of anaerobic bacteria within the oral cavity.

Ballistic and Diffusive Thermal Conductivity of Graphene

NASA Astrophysics Data System (ADS)

Saito, Riichiro; Masashi, Mizuno; Dresselhaus, Mildred S.

2018-02-01

This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. Phonon-related thermal conductivity of graphene is calculated as a function of the temperature and sample size of graphene in which the crossover of ballistic and diffusive thermal conductivity occurs at around 100 K. The diffusive thermal conductivity of graphene is evaluated by calculating the phonon mean free path for each phonon mode in which the anharmonicity of a phonon and the phonon scattering by a 13C isotope are taken into account. We show that phonon-phonon scattering of out-of-plane acoustic phonon by the anharmonic potential is essential for the largest thermal conductivity. Using the calculated results, we can design the optimum sample size, which gives the largest thermal conductivity at a given temperature for applying thermal conducting devices.

Comparison of application of various crossovers in solving inhomogeneous minimax problem modified by Goldberg model

NASA Astrophysics Data System (ADS)

Kobak, B. V.; Zhukovskiy, A. G.; Kuzin, A. P.

2018-05-01

This paper considers one of the classical NP complete problems - an inhomogeneous minimax problem. When solving such large-scale problem, there appear difficulties in obtaining an exact solution. Therefore, let us propose getting an optimum solution in an acceptable time. Among a wide range of genetic algorithm models, let us choose the modified Goldberg model, which earlier was successfully used by authors in solving NP complete problems. The classical Goldberg model uses a single-point crossover and a singlepoint mutation, which somewhat decreases the accuracy of the obtained results. In the article, let us propose using a full two-point crossover with various mutations previously researched. In addition, the work studied the necessary probability to apply it to the crossover in order to obtain results that are more accurate. Results of the computation experiment showed that the higher the probability of a crossover, the higher the quality of both the average results and the best solutions. In addition, it was found out that the higher the values of the number of individuals and the number of repetitions, the closer both the average results and the best solutions to the optimum. The paper shows how the use of a full two-point crossover increases the accuracy of solving an inhomogeneous minimax problem, while the time for getting the solution increases, but remains polynomial.

Uncertain Associations of Major Bleeding and Concurrent Use of Antiplatelet Agents and Chinese Medications: A Nested Case-Crossover Study

PubMed Central

Yam, Felix K.

2017-01-01

Despite the evidence that some commonly used Chinese medications (CMs) have antiplatelet/anticoagulant effects, many patients still used antiplatelets combined with CMs. We conducted a nested case-crossover study to examine the associations between the concomitant use of antiplatelets and CMs and major bleeding using population-based health database in Taiwan. Among the cohort of 79,463 outpatients prescribed antiplatelets (e.g., aspirin and clopidogrel) continuously, 1,209 patients hospitalized with new occurring bleeding in 2012 and 2013 were included. Those recruited patients served as their own controls to compare different times of exposure to prespecified CMs (e.g., Asian ginseng and dong quai) and antiplatelet agents. The periods of case, control 1, and control 2 were defined as 1–4 weeks, 6–9 weeks, and 13–16 weeks before hospitalization, respectively. Conditional logistic regression analyses found that concurrent use of antiplatelet drugs with any of the prespecified CMs in the case period might not significantly increase the risks of bleeding over that in the control periods (OR = 1.00, 95% CI 0.51 to 1.95 and OR = 1.13, 95% CI 0.65 to 1.97). The study showed no strong relationships between hospitalization for major bleeding events and concurrent use of antiplatelet drugs with the prespecified CMs. PMID:28831288

A case-crossover study of sleep, fatigue, and other transient exposures at workplace and the risk of non-fatal occupational injuries among the employees of an Italian academic hospital.

PubMed

Valent, Francesca; Mariuz, Marika; Liva, Giulia; Bellomo, Fabrizio; De Corti, Daniela; Degan, Stefania; Ferrazzano, Alberto; Brusaferro, Silvio

2016-11-18

Transient exposure with acute effect has been shown to affect the risk of occupational injuries in various industrial settings and at the healthcare workplace. The objective of this study has been to identify transient exposures related to occupational injury risk in an Italian teaching hospital. A case-crossover study was conducted among the employees of the University Hospital of Udine who reported an occupational injury, commuting accident, or incident involving biological risk in a 15-month period in the years 2013 and 2014. The matched-pair interval approach was used to assess the role of acute sleep deprivation whereas the usual frequency approach was used for other 13 transient exposures. Sleep hours were not associated with the risk of injuries whereas a significant risk increase was associated with fatigue, rush, distraction, emergency situations, teaching to or being taught by someone, non-compliant patients, bloody operative/work field, excess noise, complex procedures, and anger. We identified transient exposures that increased the risk of occupational injuries in an Italian teaching hospital, providing indications for interventions to increase workers' safety at the healthcare workplace. Int J Occup Med Environ Health 2016;29(6):1001-1009. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Individual and crossover effects of stress on adjustment in medical student marriages.

PubMed

Katz, J; Monnier, J; Libet, J; Shaw, D; Beach, S R

2000-07-01

High-stress individuals may benefit from social support, although their support providers may be adversely affected via stress crossover effects. Individual and crossover effects of perceived stress within medical student marriages (n = 30) were investigated. Perceived spousal support was positively associated with individuals' own marital and emotional adjustment, attenuating stress effects. With regard to crossover effects, medical students' perceived stress was significantly associated with their spouses' emotional adjustment. Further, medical students' own emotional adjustment fully mediated this crossover effect. Results suggest that the contagion of negative affect may serve as a key mechanism through which stress crossover effects operate in marriage.

Intake and time dependence of blueberry flavonoid-induced improvements in vascular function: a randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity.

PubMed

Rodriguez-Mateos, Ana; Rendeiro, Catarina; Bergillos-Meca, Triana; Tabatabaee, Setareh; George, Trevor W; Heiss, Christian; Spencer, Jeremy Pe

2013-11-01

There are very limited data regarding the effects of blueberry flavonoid intake on vascular function in healthy humans. We investigated the impact of blueberry flavonoid intake on endothelial function in healthy men and assessed potential mechanisms of action by the assessment of circulating metabolites and neutrophil NADPH oxidase activity. Two randomized, controlled, double-blind, crossover human-intervention trials were conducted with 21 healthy men. Initially, the impact of blueberry flavonoid intake on flow-mediated dilation (FMD) and polyphenol absorption and metabolism was assessed at baseline and 1, 2, 4, and 6 h after consumption of blueberry containing 766, 1278, and 1791 mg total blueberry polyphenols or a macronutrient- and micronutrient-matched control drink (0 mg total blueberry polyphenols). Second, an intake-dependence study was conducted (from baseline to 1 h) with 319, 637, 766, 1278, and 1791 mg total blueberry polyphenols and a control. We observed a biphasic time-dependent increase in FMD, with significant increases at 1-2 and 6 h after consumption of blueberry polyphenols. No significant intake-dependence was observed between 766 and 1791 mg. However, at 1 h after consumption, FMD increased dose dependently to ≤766 mg total blueberry polyphenol intake, after which FMD plateaued. Increases in FMD were closely linked to increases in circulating metabolites and by decreases in neutrophil NADPH oxidase activity at 1-2 and 6 h. Blueberry intake acutely improves vascular function in healthy men in a time- and intake-dependent manner. These benefits may be mechanistically linked to the actions of circulating phenolic metabolites on neutrophil NADPH oxidase activity. This trial was registered at clinicaltrials.gov as NCT01292954 and NCT01829542.

Hadron-quark crossover and hot neutron stars at birth

NASA Astrophysics Data System (ADS)

Masuda, Kota; Hatsuda, Tetsuo; Takatsuka, Tatsuyuki

2016-02-01

We construct a new isentropic equation of state (EOS) at finite temperature, "CRover," on the basis of the hadron-quark crossover at high density. By using the new EOS, we study the structure of hot neutron stars at birth with typical lepton fraction (Y_l=0.3-0.4) and typical entropy per baryon (hat {S}=1{-}2). Due to the gradual appearance of quark degrees of freedom at high density, the temperature T and the baryon density ρ at the center of hot neutron stars with hadron-quark crossover are found to be smaller than those without the crossover by a factor of two or more. Typical energy release due to the contraction of a hot neutron star to a cold neutron star with mass M=1.4 M_{⊙} is shown to be about 0.04 M_{⊙}, with a spin-up rate of about 14%.

Tuning across the BCS-BEC crossover in superconducting Fe1+ySexTe1-x : An angle-resolved photoemission study

NASA Astrophysics Data System (ADS)

Rinott, Shahar; Ribak, Amit; Chashka, Khanan; Randeria, Mohit; Kanigel, Amit

The crossover from Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose-Einstein condensation (BEC) was never realized in quantum materials. It is difficult to realize because, unlike in ultra cold atoms, one cannot tune the pairing interaction. We realize the BCS-BEC crossover in a nearly compensated semimetal Fe1+ySexTe1-x by tuning the Fermi energy ɛF via chemical doping, which permits us to systematically change Δ /ɛF from 0 . 16 to 0 . 50 , where Δ is the superconducting (SC) gap. We use angle-resolved photoemission spectroscopy to measure the Fermi energy, the SC gap and characteristic changes in the SC state electronic dispersion as the system evolves from a BCS to a BEC regime. Our results raise important questions about the crossover in multi-band superconductors which go beyond those addressed in the context of cold atoms.

What about the leader? Crossover of emotional exhaustion and work engagement from followers to leaders.

PubMed

Wirtz, Nina; Rigotti, Thomas; Otto, Kathleen; Loeb, Carina

2017-01-01

Although a growing body of research links leadership behavior to follower health, comparatively little is known about the health effects of being in the lead. This longitudinal study of 315 team members and 67 leaders examined the crossover of emotional exhaustion and work engagement from followers to leaders. Leader emotional self-efficacy was tested as a moderator in the crossover process. Multiple regression analyses revealed that followers' work engagement was positively related to leaders' work engagement eight months later, controlling for followers' tenure with the leader, leader gender, autonomy, workload, and work engagement at Time 1. Leaders' emotional self-efficacy did not moderate the crossover of work engagement. Followers' emotional exhaustion was not directly related to leaders' emotional exhaustion over time. We did find a significant interaction effect for follower emotional exhaustion and leader emotional self-efficacy. This study is the first to show that crossover of emotional exhaustion and work engagement can unfold over time from team members to leaders. Main theoretical implications lie in the finding that-in line with job demands-resources theory-followers' psychological states can pose a demand or resource for leaders, and influence their well-being. For practitioners, our results offer valuable insights regarding the design of organizational health interventions as well as leadership development measures. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

DNA methylation epigenetically silences crossover hot spots and controls chromosomal domains of meiotic recombination in Arabidopsis.

PubMed

Yelina, Nataliya E; Lambing, Christophe; Hardcastle, Thomas J; Zhao, Xiaohui; Santos, Bruno; Henderson, Ian R

2015-10-15

During meiosis, homologous chromosomes undergo crossover recombination, which is typically concentrated in narrow hot spots that are controlled by genetic and epigenetic information. Arabidopsis chromosomes are highly DNA methylated in the repetitive centromeres, which are also crossover-suppressed. Here we demonstrate that RNA-directed DNA methylation is sufficient to locally silence Arabidopsis euchromatic crossover hot spots and is associated with increased nucleosome density and H3K9me2. However, loss of CG DNA methylation maintenance in met1 triggers epigenetic crossover remodeling at the chromosome scale, with pericentromeric decreases and euchromatic increases in recombination. We used recombination mutants that alter interfering and noninterfering crossover repair pathways (fancm and zip4) to demonstrate that remodeling primarily involves redistribution of interfering crossovers. Using whole-genome bisulfite sequencing, we show that crossover remodeling is driven by loss of CG methylation within the centromeric regions. Using cytogenetics, we profiled meiotic DNA double-strand break (DSB) foci in met1 and found them unchanged relative to wild type. We propose that met1 chromosome structure is altered, causing centromere-proximal DSBs to be inhibited from maturation into interfering crossovers. These data demonstrate that DNA methylation is sufficient to silence crossover hot spots and plays a key role in establishing domains of meiotic recombination along chromosomes. © 2015 Yelina et al.; Published by Cold Spring Harbor Laboratory Press.

An alternative approach for neural network evolution with a genetic algorithm: crossover by combinatorial optimization.

PubMed

García-Pedrajas, Nicolás; Ortiz-Boyer, Domingo; Hervás-Martínez, César

2006-05-01

In this work we present a new approach to crossover operator in the genetic evolution of neural networks. The most widely used evolutionary computation paradigm for neural network evolution is evolutionary programming. This paradigm is usually preferred due to the problems caused by the application of crossover to neural network evolution. However, crossover is the most innovative operator within the field of evolutionary computation. One of the most notorious problems with the application of crossover to neural networks is known as the permutation problem. This problem occurs due to the fact that the same network can be represented in a genetic coding by many different codifications. Our approach modifies the standard crossover operator taking into account the special features of the individuals to be mated. We present a new model for mating individuals that considers the structure of the hidden layer and redefines the crossover operator. As each hidden node represents a non-linear projection of the input variables, we approach the crossover as a problem on combinatorial optimization. We can formulate the problem as the extraction of a subset of near-optimal projections to create the hidden layer of the new network. This new approach is compared to a classical crossover in 25 real-world problems with an excellent performance. Moreover, the networks obtained are much smaller than those obtained with classical crossover operator.

Randomly diluted xy and resistor networks near the percolation threshold

NASA Astrophysics Data System (ADS)

Harris, A. B.; Lubensky, T. C.

1987-05-01

A formulation based on that of Stephen for randomly diluted systems near the percolation threshold is analyzed in detail. By careful consideration of various limiting procedures, a treatment of xy spin models and resistor networks is given which shows that previous calculations (which indicate that these systems having continuous symmetry have the same crossover exponents as the Ising model) are in error. By studying the limit wherein the energy gap goes to zero, we exhibit the mathematical mechanism which leads to qualitatively different results for xy-like as contrasted to Ising-like systems. A distinctive feature of the results is that there is an infinite sequence of crossover exponents needed to completely describe the probability distribution for R(x,x'), the resistance between sites x and x'. Because of the difference in symmetry between the xy model and the resistor network, the former has an infinite sequence of crossover exponents in addition to those of the resistor network. The first crossover exponent φ1=1+ɛ/42 governs the scaling behavior of R(x,x') with ||x-x'||≡r: [R(x,x')]c~xφ1/ν, where [ ]c indicates a conditional average, subject to x and x' being in the same cluster, ν is the correlation length exponent for percolation, and ɛ=6-d, where d is the spatial dimensionality. We give a detailed analysis of the scaling properties of the bulk conductivity and the anomalous diffusion constant introduced by Gefen et al. Our results show conclusively that the Alexander-Orbach conjecture, while numerically quite accurate, is not exact, at least in high spatial dimension. We also evaluate various amplitude ratios associated with susceptibilities, χn involving the nth power of the resistance R(x,x'), e.g., &χ2χ0/χ21=2[1+(19ɛ/420)]. In an appendix we outline how the calculation can be extended to treat the diluted m-component spin model for m>2. As expected, the results for φ1 remain valid for m>2. The techniques described here have led to several recent calculations of various infinite families of exponents.

Balloon-Assisted Tracking Use Reduces Radial Artery Access Failure in an Experienced Radial Center and is Feasible During Primary PCI for STEMI.

PubMed

Obaid, Daniel; Hailan, Ahmed; Chase, Alexander; Dorman, Stephen; Jenkins, Geraint; Raybould, Adrian; Ramsey, Mark; Thomas, Phillip; Smith, David; Ionescu, Adrian

2017-07-01

This prospective study assesses balloon-assisted tracking (BAT) in reducing radial access failure during percutaneous coronary intervention (PCI). Arterial spasm prevents PCI from the radial artery in a small percentage of cases. A total of 2223 consecutive patients undergoing PCI from the radial approach were analyzed. Radial access failure mode and requirement for crossover to femoral access during a 12-month run-in period were compared with the following 14-month period with routine BAT usage. During the 14-month study period, 1334 radial PCIs were attempted. Twenty-six patients switched to femoral at an early stage, while 76 encountered radial spasm and underwent successful BAT in 69 cases (91%), giving a total crossover rate to femoral of 33/1334 (2.5%). Utilizing BAT rather than a femoral puncture reduced our institution's radial-femoral crossover rate from 7.6% to 2.5% (P<.01), which is also significantly lower than the radial-femoral crossover rate in the 12 months before BAT implementation (6.1%; P<.01). Mean procedure times were similar for those requiring BAT compared with conventional radial access (51.3 ± 21.3 min vs 47.9 ± 23.7 min; P=.23), and those crossing straight to femoral (BAT not attempted) (60.7 ± 31.9 min; P=.10). Mean first device/balloon time for the BAT-assisted primary PCI cases (22.6 ± 9.4 min) was similar to cases that had radial difficulties and converted to femoral without attempting BAT (25.8 ± 13.4 min; P=.54). BAT allowed catheter passage despite radial spasm in 91% of cases, significantly reducing the institution's rate of femoral crossover. During radial spasm in primary PCI, using BAT did not delay reperfusion compared with femoral crossover.

An innovative acupuncture treatment for primary dysmenorrhea: a randomized cross-over pilot study

PubMed Central

Wade, Christine M.; Abercrombie, Priscilla D.; Gomolak, Denise

2013-01-01

Background/Objective Dysmenorrhea is highly prevalent among adolescent women and a major cause of activity restriction. Standard pharmaceuticals used to treat dysmenorrhea are not effective for all women and have side effects that limit their use. Our study objective was to examine feasibility, acceptability, and preliminary effects of acupuncture point injection of vitamin K1 as an alternative treatment for primary dysmenorrhea among US women. Methods/Design We conducted a pilot study using a crossover trial design. Women with primary dysmenorrhea were randomized to receive vitamin K1 injection in the Spleen-6 acupuncture point at the start of menstruation followed by saline in a non-acupuncture point after two months, or the reverse order of treatments. Setting/Participants The study was conducted in the San Francisco Bay Area among women 18 and 25 years of age diagnosed with primary dysmenorrhea; fourteen women completed all study visits. Primary Outcome Measure Dysmenorrhea pain intensity was measured using a 0–10 numeric rating scale before and after injections. Results Women had an average 2.5 point decrease in pain after vitamin K1 injection in Spleen-6 (p < 0.001) compared with a 1.8 point decrease after saline (p < 0.001). Change scores of vitamin K1 compared with saline injection approached statistical significance (p < 0.10). Intensity and duration of menstrual symptoms measured by the Cox Retrospective Symptom Score also decreased following injections. After participating, 94% would still agree to go through with the injection therapy and 77% reported they would come every month were the treatment available. Conclusions Findings suggest high acceptability of acupuncture point injection of vitamin K1 as treatment for primary dysmenorrhea among young women in San Francisco. Pain decreased with both treatments, with a trend toward greater pain reduction for vitamin K1/Spleen-6 injection. This is consistent with outcomes from the Obstetrics & Gynecology Hospital in Shanghai, China, where the protocol was developed. PMID:24445356

A Randomized Crossover Study of Web-Based Media Literacy to Prevent Smoking

ERIC Educational Resources Information Center

Shensa, Ariel; Phelps-Tschang, Jane; Miller, Elizabeth; Primack, Brian A.

2016-01-01

Feasibly implemented Web-based smoking media literacy (SML) programs have been associated with improving SML skills among adolescents. However, prior evaluations have generally had weak experimental designs. We aimed to examine program efficacy using a more rigorous crossover design. Seventy-two ninth grade students completed a Web-based SML…

Father Influences on Employed Mothers' Work-Family Balance

ERIC Educational Resources Information Center

Fagan, Jay; Press, Julie

2008-01-01

This study employed the ecological systems perspective and gender ideology theory to examine the influence of fathers' paid work-family crossover and family involvement on self-reports of work-family balance by employed mothers with children under the age of 13 (N = 179). Multiple regression analyses revealed that fathers' crossover factors had a…

Tic Reduction with Risperidone Versus Pimozide in a Randomized, Double-Blind, Crossover Trial

ERIC Educational Resources Information Center

Gilbert, Donald L.; Batterson, J. Robert; Sethuraman, Gopalan; Sallee, Floyd R.

2004-01-01

Objective: To compare the tic suppression, electrocardiogram (ECG) changes, weight gain, and side effect profiles of pimozide versus risperidone in children and adolescents with tic disorders. Method: This was a randomized, double-blind, crossover (evaluable patient analysis) study. Nineteen children aged 7 to 17 years with Tourette's or chronic…

The crossover of daily work engagement: test of an actor-partner interdependence model.

PubMed

Bakker, Arnold B; Xanthopoulou, Despoina

2009-11-01

This study of 62 dyads of employees (N = 124) examined the crossover of work engagement-a positive, fulfilling, work-related state of mind that is characterized by vigor, dedication, and absorption. We hypothesized that work engagement crosses over from an employee (the actor) to his or her colleague (the partner) on a daily basis. The frequency of daily communication was expected to moderate the crossover of daily work engagement, which in turn would relate to colleagues' daily performance. Participants first filled in a general questionnaire and then completed a diary study over 5 consecutive workdays. The hypotheses were tested with multilevel analyses, using an actor-partner interdependence model. Results confirmed the crossover of daily work engagement, but only on days when employees within a dyad interacted more frequently than usual. Moreover, we found that actor's work engagement (particularly vigor), when frequently communicated, had a positive indirect relationship with partner's performance through partner's work engagement. Finally, results showed that actor's vigor was negatively related to partner's performance when communication was low. However, this negative effect was counteracted when mediated by the vigor of the partner.

Testing equality and interval estimation of the generalized odds ratio in ordinal data under a three-period crossover design.

PubMed

Lui, Kung-Jong; Chang, Kuang-Chao; Lin, Chii-Dean

2017-06-01

The crossover design can be of use to save the number of patients or improve power of a parallel groups design in studying treatments to noncurable chronic diseases. We propose using the generalized odds ratio for paired sample data to measure the relative effects in ordinal data between treatments and between periods. We show that one can apply the commonly used asymptotic and exact test procedures for stratified analysis in epidemiology to test non-equality of treatments in ordinal data, as well as obtain asymptotic and exact interval estimators for the generalized odds ratio under a three-period crossover design. We further show that one can apply procedures for testing the homogeneity of the odds ratio under stratified sampling to examine whether there are treatment-by-period interactions. We use the data taken from a three-period crossover trial studying the effects of low and high doses of an analgesic versus a placebo for the relief of pain in primary dysmenorrhea to illustrate the use of these test procedures and estimators proposed here.

Experimental investigation of cross-over jets in a rib-roughened trailing-edge cooling channel

NASA Astrophysics Data System (ADS)

Xue, Fei

Increasing the rotor inlet temperature can dramatically increase the efficiency and power output of the gas turbine engine. However, the melting point of turbine blade material limits the realistic upper bound of the rotor inlet temperature. As a result, the development of high temperature turbine blade material and advanced turbine blade cooling technology determines the future of turbine blade engine. Adding impingement jet holes and rib turbulators in the inner cooling channel of the gas turbine blades are two effective ways to enhance the cooling effects. The purpose of this study is to figure out the influence of different combinations of jet holes and rib turbulators on the heat transfer efficiency. A tabletop scale test model is used in the study to simulate the cooling cavity of trailing edge and its feed channel in a real gas turbine blade. The Dimensional Analysis Theory is used in the study to eliminate the influence of scaling. Two different crossover slots are tested with 5 different rib arrangements, and each of the test geometries is tested for 6 jet Reynolds numbers ranging from 10,000 to 36,000. The two different crossover slots are the crossover slots with 0 and 5 degree tilt angles. The four different rib arrangements are ribs with 0 degree, 45 degree, 90 degree and 135 degree angles of attack with respect to the flow direction. Furthermore, a smooth test section (no ribs) was also tested. The steady state liquid crystal thermography is used to quantify the heat transfer performance of the target areas. The variation of Nusselt number versus Reynolds number is plotted for each of the 10 geometries. Also, the variation of Nusselt number versus Reynolds number are compared for different rib angles of attack with the same crossover slot tilt angle, and between different crossover slots tilt angles with the same rib angle. The results show that, the area-weighted average Nusselt number increases monotonically with the Reynolds number; the target areas near the open end have a larger Nusselt number comparing with the ones near the close end; the 90 degree rib angle has the highest Nusselt number among the 4 rib angles of attack and the smooth wall channel; the crossover slots with 0 degree tilt angle produce higher convective heat transfer coefficients than the crossover slots with 5 degree tilt angle. Possible physical explanations for the result are offered by the author.

Two-way crossover bioequivalence study of alendronate sodium tablets in healthy, non-smoking male volunteers under fasted conditions.

PubMed

Thudi, Nageshwar Rao; Gagnon, Stéphanie; Hussain, Saleh; Abolfathi, Zohreh; Singla, Ajay; Pai, Raveendra; Kumar, Sudershan; Monif, Tausif

2009-01-01

This study was conducted in order to assess the bioequivalence of two different formulations containing 70 mg alendronate sodium (CAS 121268-17-5) under fasted conditions. One hundred twenty-two healthy male volunteers were enrolled in an open label, randomized, crossover design with a wash-out period of 20 days in one study center. Urine samples were collected up to 36 h post-dose, and the concentrations of alendronic acid were determined using a high performance liquid chromatographic method with pre-derivatization and fluorescence detection (HPLC/FL) method. The mean Ae(0-t) were 604.24 +/- 348.73 microg and 627.36 +/- 327.99 microg, while the mean R(max) were 193.87 +/- 114.68 microg/h and 202.00 +/- 107.83 microg/h for the test and reference formulations, respectively. The T(max) of the test and reference tablets were 1.26 +/- 0.58 h and 1.26 +/- 0.51 h, respectively. No significant differences of pharmacokinetic parameters between the two studied formulations were found. The 90% confidence intervals for the primary target parameters, intra-individual ratios for Ae(0-t) and R(max) of alendronic acid, were between 0.86-1.00 and 0.85-1.01, respectively, and thus within the acceptance range for bioequivalence criteria. In the light of the present study it can be concluded that the test formulation is bioequivalent to the reference formulation.

Hydrodynamic-to-ballistic crossover in Dirac materials

NASA Astrophysics Data System (ADS)

Svintsov, D.

2018-03-01

We develop an analytically solvable classical kinetic model of spatially dispersive transport in Dirac materials accounting for strong electron-electron (e-e) and electron-hole (e-h) collisions. We use this model to track the evolution of graphene conductivity and properties of its collective excitations across the hydrodynamic-to-ballistic crossover. We find the relaxation rate of electric current by e-e collisions that is possible due to the lack of Galilean invariance and introduce a universal numerical measure of this noninvariance. We find the two branches of collective excitations in the Dirac fluid: plasmons and electron-hole sound. The sound waves persist at frequencies exceeding the e-e collision frequency, have a small viscous damping at the neutrality point, but acquire large damping due to e-h friction even at slight doping. On the contrary, plasmons acquire strong frictional damping at the neutrality point and become well defined in doped samples.

The Association Between Urban Tree Cover and Gun Assault: A Case-Control and Case-Crossover Study.

PubMed

Kondo, Michelle C; South, Eugenia C; Branas, Charles C; Richmond, Therese S; Wiebe, Douglas J

2017-08-01

Green space and vegetation may play a protective role against urban violence. We investigated whether being near urban tree cover during outdoor activities was related to being assaulted with a gun. We conducted geographic information systems-assisted interviews with boys and men aged 10-24 years in Philadelphia, Pennsylvania, including 135 patients who had been shot with a firearm and 274 community controls, during 2008-2011. Each subject reported a step-by-step mapped account of where and with whom they traveled over a full day from waking until being assaulted or going to bed. Geocoded path points were overlaid on mapped layers representing tree locations and place-specific characteristics. Conditional logistic regressions were used to compare case subjects versus controls (case-control) and case subjects at the time of injury versus times earlier that day (case-crossover). When comparing cases at the time of assault to controls matched at the same time of day, being under tree cover was inversely associated with gunshot assault (odds ratio (OR) = 0.70, 95% confidence interval (CI): 0.55, 0.88), especially in low-income areas (OR = 0.69, 95% CI: 0.54, 0.87). Case-crossover models confirmed this inverse association overall (OR = 0.55, 95% CI: 0.34, 0.89) and in low-income areas (OR = 0.54, 95% CI: 0.33, 0.88). Urban greening and tree cover may hold promise as proactive strategies to decrease urban violence. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Bioequivalence evaluation of two brands of amoxicillin/clavulanic acid 250/125 mg combination tablets in healthy human volunteers: use of replicate design approach.

PubMed

Idkaidek, Nasir M; Al-Ghazawi, Ahmad; Najib, Naji M

2004-12-01

The purpose of this study was to apply a replicate design approach to a bioequivalence study of amoxicillin/clavulanic acid combination following a 250/125 mg oral dose to 23 subjects, and to compare the analysis of individual bioequivalence with average bioequivalence. This was conducted as a 2-treatment 2-sequence 4-period crossover study. Average bioequivalence was shown, while the results from the individual bioequivalence approach had no success in showing bioequivalence. In conclusion, the individual bioequivalence approach is a strong statistical tool to test for intra-subject variances and also subject-by-formulation interaction variance compared with the average bioequivalence approach. copyright (c) 2004 John Wiley & Sons, Ltd.

Spin crossover in ferropericlase and velocity heterogeneities in the lower mantle

NASA Astrophysics Data System (ADS)

Wu, Z.; Wentzcovitch, R. M.

2014-12-01

Ferropericlase (Fp) is believed to be the second most abundant phase in the lower mantle. Since the discovery of the high spin (HS) to low spin (LS) crossover in iron in Fp [1], this phenomenon has been investigated extensively experimentally and theoretically. This is a broad and smooth crossover that takes place throughout most of the lower mantle and does not produce an obvious signature in radial velocity or density profiles [2]. Therefore, the spin transition has been generally considered to be invisible to seismic waves. This study, however, shows that it can produce a peculiar effect on lateral velocity heterogeneities at certain depths[3]. Deciphering the origin of seismic velocity heterogeneities in the mantle is crucial to understanding internal structures and processes at work in the Earth. The spin crossover in iron introduces unfamiliar effects on seismic velocities. First principles calculations indicate that anti-correlation between shear velocity (VS) and bulk sound velocity (Vφ) in the mantle, usually interpreted as compositional heterogeneity, can also be produced in homogeneous aggregates containing Fp. The spin crossover also suppresses thermally induced heterogeneity in VP but not in VS. This effect is observed in tomographic models at conditions where the spin crossover in Fp is expected in the lower mantle. In addition, the one-of-a-kind signature of this spin crossover in the RS/P () heterogeneity ratio might be a useful "fingerprint" to detect the presence of Fp in the lower mantle. [1] Badro J, et al. (2003) Science 300(5620):789-791. [2] Wu Z, Justo J. F., and Wentzcovitch R. M., (2013). Phys. Rev. Lett. 110. 228501-5 [3]Wu Z., and Wentzcovitch R. M., (2014) Proc Natl Acad Sci USA. www.pnas.org/cgi/doi/10.1073/pnas.1322427111

Tuning porosity and radial mechanical properties of DNA origami nanotubes via crossover design

NASA Astrophysics Data System (ADS)

Ma, Zhipeng; Kawai, Kentaro; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Tabata, Osamu

2017-06-01

DNA origami nanotubes are utilized as structural platforms for the fabrication of various micro/nanosystems for drug delivery, optical or biological sensing, and even nanoscale robots. Their radial structural and mechanical properties, which play a crucial role in the effective use of micro/nanosystems, have not been fully studied. In particular, the effects of crossovers, which are basic structures for rationally assembling double-stranded DNA (dsDNA) helices into a nanotube configuration, have not yet been characterized experimentally. To investigate the effects of crossovers on the porosity and the radial mechanical properties of DNA origami nanotubes, we fabricated a DNA origami nanotube with varied crossover designs along the nanotube axis. The radial geometry of the DNA origami nanotube is experimentally characterized by both atomic force microscopy (AFM) and electron cryomicroscopy (cryo-EM). Moreover, the radial mechanical properties of the DNA origami nanotube including the radial modulus are directly measured by force-distance-based AFM. These measurements reveal that the porosity and the radial modulus of DNA origami nanotubes can be tuned by adjusting the crossover design, which enables the optimal design and construction of DNA origami nanostructures for various applications.

Conductance fluctuation of edge-disordered graphene nanoribbons: Crossover from diffusive transport to Anderson localization

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

Takashima, Kengo; Yamamoto, Takahiro, E-mail: takahiro@rs.tus.ac.jp; Department of Liberal Arts

Conductance fluctuation of edge-disordered graphene nanoribbons (ED-GNRs) is examined using the non-equilibrium Green's function technique combined with the extended Hückel approximation. The mean free path λ and the localization length ξ of the ED-GNRs are determined to classify the quantum transport regimes. In the diffusive regime where the length L{sub c} of the ED-GNRs is much longer than λ and much shorter than ξ, the conductance histogram is given by a Gaussian distribution function with universal conductance fluctuation. In the localization regime where L{sub c}≫ξ, the histogram is no longer the universal Gaussian distribution but a lognormal distribution that characterizesmore » Anderson localization.« less

50 CFR 660.320 - Open access fishery-crossover provisions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. The crossover provisions listed at § 660.60(h)(7), apply to vessels fishing in the open access fishery. [76 FR...

50 CFR 660.320 - Open access fishery-crossover provisions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. The crossover provisions listed at § 660.60(h)(7), apply to vessels fishing in the open access fishery. [76 FR...

50 CFR 660.320 - Open access fishery-crossover provisions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. The crossover provisions listed at § 660.60(h)(7), apply to vessels fishing in the open access fishery. [76 FR...

Recent Studies on Methanol Crossover in Liquid-Feed Direct Methanol Fuel Cells

NASA Technical Reports Server (NTRS)

Valdez, T. I.; Narayanan, S. R.

2000-01-01

In this work, the effects of methanol crossover and airflow rates on the cathode potential of an operating direct methanol fuel cell are explored. Techniques for quantifying methanol crossover in a fuel cell and for separating the electrical performance of each electrode in a fuel cell are discussed. The effect of methanol concentration on cathode potential has been determined to be significant. The cathode is found to be mass transfer limited when operating on low flow rate air and high concentrations of methanol. Improvements in cathode structure and operation at low methanol concentration have been shown to result in improved cell performance.

Meiotic recombination protein Rec12: functional conservation, crossover homeostasis and early crossover/non-crossover decision

PubMed Central

Kan, Fengling; Davidson, Mari K.; Wahls, Wayne P.

2011-01-01

In fission yeast and other eukaryotes, Rec12 (Spo11) is thought to catalyze the formation of dsDNA breaks (DSBs) that initiate homologous recombination in meiosis. Rec12 is orthologous to the catalytic subunit of topoisomerase VI (Top6A). Guided by the crystal structure of Top6A, we engineered the rec12 locus to encode Rec12 proteins each with a single amino acid substitution in a conserved residue. Of 21 substitutions, 10 significantly reduced or abolished meiotic DSBs, gene conversion, crossover recombination and the faithful segregation of chromosomes. Critical residues map within the metal ion-binding pocket toprim (E179A, D229A, D231A), catalytic region 5Y-CAP (R94A, D95A, Y98F) and the DNA-binding interface (K201A, G202E, R209A, K242A). A subset of substitutions reduced DSBs but maintained crossovers, demonstrating crossover homeostasis. Furthermore, a strong separation of function mutation (R304A) suggests that the crossover/non-crossover decision is established early by a protein–protein interaction surface of Rec12. Fission yeast has multiple crossovers per bivalent, and chromosome segregation was robust above a threshold of about one crossover per bivalent, below which non-disjunction occurred. These results support structural and functional conservation among Rec12/Spo11/Top6A family members for the catalysis of DSBs, and they reveal how Rec12 regulates other features of meiotic chromosome dynamics. PMID:21030440

Transport signatures of topology protected quantum criticality in Majorana islands

NASA Astrophysics Data System (ADS)

Papaj, Michal; Zhu, Zheng; Fu, Liang

Using numerical renormalization group we study a topological superconductor island coupled to three metallic leads in the vicinity of the charge degeneracy point. We show that the system flows to a non-Fermi liquid fixed point at low temperatures with fractional quantized DC conductance of 2 / 3e2 / h . Our proposal is experimentally feasible due to a much larger crossover temperature than in the previously studied cases and the robustness of the setup against the channel coupling anisotropy and charge degeneracy detuning. Including Majorana hybridization drives the system into a Fermi liquid phase at very low temperatures. The two proposed experimental signatures of multi-terminal electron teleportation include nonmonotonic temperature dependence of DC conductance and emergence of a plateau at 2 / 3e2 / h in tunnel coupling dependence of DC conductance. This work is funded by the DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award de-sc0010526 (ZZ and LF) and the NSF STC ''Center for Integrated Quantum Materials'' under Cooperative Agreement No. DMR-1231319 (MP).

Levothyroxine soft capsules demonstrate bioequivalent pharmacokinetic exposure with the European reference tablets in healthy volunteers under fasting conditions.

PubMed

Al-Numani, Dina; Scarsi, Claudia; Ducharme, Murray P

2016-02-01

To assess the bioequivalence (BE) potential under fasting conditions between levothyroxine soft capsules and the European reference tablet formulation. Two studies were conducted to assess the BE potential as per European regulations. Study 1 was a two-way crossover BE study comparing a high strength of levothyroxine soft capsules versus levothyroxine tablets (200 μg), while study 2 was a three-way crossover dosage form proportionality study between low, medium, and high strengths of soft capsules. 70 healthy adult subjects participated in the two studies. Each treatment consisted of a 600-μg dose of levothyroxine sodium, administered under fasting conditions. Blood samples were collected for levothyroxine (T4) assay prior to dosing and up to 72 hours post dose. A washout of 35 days separated treatments in each study. Pharmacokinetics was assessed using noncompartmental methods. A total of 61 subjects completed the studies. Baseline-adjusted total T4 ratios (test/reference) and 90% confidence intervals (CIs) between soft capsules and tablets were within 80.00 - 125.00%. Comparison of the three strengths of soft capsules indicated pharmacokinetic equivalence between them (ratios and 90% CIs were contained within 80.00 - 125.00%). Overall, levothyroxine sodium was well tolerated with all products when given as single oral doses of 600 μg, except for 1 serious adverse event of secondary bacteremia reported in study 2, deemed not to be related to treatment. Levothyroxine soft capsules meet BE criteria in terms of systemic exposure when compared to a European reference tablet under fasting conditions in healthy volunteers.

Difference in Learning among Students Doing Pen-and-Paper Homework Compared to Web-Based Homework in an Introductory Statistics Course

ERIC Educational Resources Information Center

Jonsdottir, Anna Helga; Bjornsdottir, Audbjorg; Stefansson, Gunnar

2017-01-01

A repeated crossover experiment comparing learning among students handing in pen-and-paper homework (PPH) with students handing in web-based homework (WBH) has been conducted. The system used in the experiments, the tutor-web, has been used to deliver homework problems to thousands of students in mathematics and statistics over several years.…

Double-Blind, Placebo-Controlled, Crossover Study of the Efficacy and Safety of Lisdexamfetamine Dimesylate in College Students with ADHD

ERIC Educational Resources Information Center

DuPaul, George J.; Weyandt, Lisa L.; Rossi, Joseph S.; Vilardo, Brigid A.; O'Dell, Sean M.; Carson, Kristen M.; Verdi, Genevieve; Swentosky, Anthony

2012-01-01

Objective: To evaluate stimulant medication on symptoms and functioning for college students with ADHD using double-blind, placebo-controlled, crossover design. Method: Participants included 24 college students with ADHD and 26 college students without psychopathology. Lisdexamfetamine dimesylate (LDX) was examined for ADHD participants over five…

Imaging Josephson vortices on the surface superconductor Si(111)-(√7×√3)-In using a scanning tunneling microscope.

PubMed

Yoshizawa, Shunsuke; Kim, Howon; Kawakami, Takuto; Nagai, Yuki; Nakayama, Tomonobu; Hu, Xiao; Hasegawa, Yukio; Uchihashi, Takashi

2014-12-12

We have studied the superconducting Si(111)-(√7×√3)-In surface using a ³He-based low-temperature scanning tunneling microscope. Zero-bias conductance images taken over a large surface area reveal that vortices are trapped at atomic steps after magnetic fields are applied. The crossover behavior from Pearl to Josephson vortices is clearly identified from their elongated shapes along the steps and significant recovery of superconductivity within the cores. Our numerical calculations combined with experiments clarify that these characteristic features are determined by the relative strength of the interterrace Josephson coupling at the atomic step.

Mott transition between a spin-liquid insulator and a metal in three dimensions.

PubMed

Podolsky, Daniel; Paramekanti, Arun; Kim, Yong Baek; Senthil, T

2009-05-08

We study a bandwidth controlled Mott metal-insulator transition (MIT) from a Fermi-liquid metal to a quantum spin-liquid insulator in three dimensions. Using a slave rotor approach including gauge fluctuations, we obtain a continuous MIT and discuss finite temperature crossovers in its vicinity. We show that the specific heat C approximately Tlnln(1/T) at the MIT and that the metallic state near the MIT should exhibit a "conductivity minimum" as a function of temperature. We suggest Na4Ir3O8 as a candidate to test our predictions and compute its electron spectral function at the MIT.

Modafinil Improves Real Driving Performance in Patients with Hypersomnia: A Randomized Double-Blind Placebo-Controlled Crossover Clinical Trial

PubMed Central

Philip, Pierre; Chaufton, Cyril; Taillard, Jacques; Capelli, Aurore; Coste, Olivier; Léger, Damien; Moore, Nicholas; Sagaspe, Patricia

2014-01-01

Study Objective: Patients with excessive daytime sleepiness (EDS) are at high risk for driving accidents, and physicians are concerned by the effect of alerting drugs on driving skills of sleepy patients. No study has up to now investigated the effect of modafinil (a reference drug to treat EDS in patients with hypersomnia) on on-road driving performance of patients suffering from central hypersomnia. The objective is to evaluate in patients with central hypersomnia the effect of a wake-promoting drug on real driving performance and to assess the relationship between objective sleepiness and driving performance. Design and Participants: Randomized, crossover, double-blind placebo-controlled trial conducted among 13 patients with narcolepsy and 14 patients with idiopathic hypersomnia. Patients were randomly assigned to receive modafinil (400 mg) or placebo for 5 days prior to the driving test. Each condition was separated by at least 3 weeks of washout. Measurements: Mean number of Inappropriate Line Crossings, Standard Deviation of Lateral Position of the vehicle and mean sleep latency in the Maintenance of Wakefulness Test were assessed. Results: Modafinil reduced the mean number of Inappropriate Line Crossings and Standard Deviation of Lateral Position of the vehicle compared to placebo (F(1,25) = 4.88, P < 0.05 and F(1,25) = 3.87, P = 0.06 tendency). Mean sleep latency at the Maintenance of Wakefulness Test significantly correlated with the mean number of Inappropriate Line Crossings (r = -0.41, P < 0.001). Conclusions: Modafinil improves driving performance in patients with narcolepsy and idiopathic hypersomnia. The Maintenance of Wakefulness Test is a suitable clinical tool to assess fitness to drive in this population. Citation: Philip P; Chaufton C; Taillard J; Capelli A; Coste O; Léger D; Moore N; Sagaspe P. Modafinil improves real driving performance in patients with hypersomnia: a randomized double-blind placebo-controlled crossover clinical trial. SLEEP 2014;37(3):483-487. PMID:24587570

Effects of simvastatin and oral contraceptive agent on polycystic ovary syndrome: prospective, randomized, crossover trial.

PubMed

Banaszewska, Beata; Pawelczyk, Leszek; Spaczynski, Robert Z; Dziura, James; Duleba, Antoni J

2007-02-01

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism and cardiovascular risks including dyslipidemia and systemic inflammation. In vitro, statins decrease proliferation and steroidogenesis of ovarian theca-interstitial cells. The study objective was to compare effects of two treatments of PCOS: simvastatin plus oral contraceptive pill (OCP) vs. OCP alone. In a prospective, crossover trial, 48 women with PCOS were randomized to either simvastatin plus OCP for 12 wk followed by OCP alone for an additional 12 wk, or to OCP alone for 12 wk and, subsequently, simvastatin plus OCP for an additional 12 wk. Evaluations were performed at baseline, after 12 wk (crossover), and after 24 wk. Data were analyzed using a random effects model. The study was conducted in an academic medical center. Serum total testosterone was the primary outcome measure. Total testosterone decreased by 38% after Statin + OCP, whereas OCP alone led to a 26% decrease; the statin-attributable effect was significant (P < 0.004). Free testosterone declined by 58% after Statin + OCP, significantly more than the 35% decline after OCP alone (P = 0.006). Hirsutism decreased by 8.1% after Statin + OCP, a greater effect than the 4.7% decrease after OCP alone (P = 0.02). Statin decreased LH, but not FSH or prolactin. Statin + OCP decreased total and low-density lipoprotein cholesterol by 7.5% and 20%, respectively. OCP alone led to a 5% increase of total cholesterol without effect on low-density lipoprotein cholesterol. Statin prevented OCP induced increase of triglycerides. C-reactive protein decreased by 45% after Statin + OCP, a significantly different effect (P = 0.006) than a 6% increase after OCP alone. Soluble vascular cell adhesion molecule 1 decreased by 18% after Statin + OCP, a greater decline than the 10% decrease after OCP alone (P = 0.01). Simvastatin improved endocrine/clinical aspects of PCOS and had beneficial effects on lipid profile and markers of systemic inflammation.

The impact of dark chocolate intake on arterial elasticity in individuals with HIV/AIDS undergoing ART: a randomized, double-blind, crossover trial.

PubMed

Teixeira, Andrea Mariana Nunes da Costa; Luzia, Liania Alves; de Souza, Suelen Jorge; de Almeida Petrilli, Aline; Pontilho, Patrícia de Moraes; de Souza, Jose Maria Pacheco; Segurado, Aluísio Augusto Cotrim; Efraim, Priscila; Picone, Camila de Melo; Rondo, Patrícia Helen de Carvalho

2017-06-21

An increase in the frequency of cardiovascular diseases has been observed in the HIV/AIDS population. Studies involving healthy subjects or subjects with other diseases have shown benefits of chocolate supplementation on endothelial function and vasodilation. We evaluate the impact of chocolate consumption on arterial elasticity in people living with human immunodeficiency virus - PLHIV. A double-blind, crossover trial including 110 PLHIV (19 to 59 years) on antiretroviral therapy - ART for at least 6 months and with a viral load of <500 copies per mL was conducted. All subjects were randomly assigned to 15-d dietary supplements containing dark chocolate or placebo with a 15-d washout period. Each participant received one of the two sequences: A (dark chocolate, placebo chocolate); B (placebo chocolate, dark chocolate). Arterial elasticity was measured using the HDI/PulseWave™ CR-2000 CardioVascular Profiling System®. Body composition, lipid profile, C-reactive protein, and thiobarbituric acid reactive substances were also assessed. Analysis of variance (ANOVA) for repeated measures using the Stata 11.0® program was used for cross-over analysis. Most subjects were men (59.0%) and Caucasian (46.1%) and the mean age was 44.6 ± 7.1 years. The mean time since diagnosis of HIV infection was 13.7 ± 5.3 years and the mean duration of ART was 12.9 ± 4.2 years. Chocolate consumption resulted in significant alterations in the large artery elasticity index - LAEI (p = 0.049) and the mean concentration of HDL-c was higher after supplementation with dark chocolate (p = 0.045). This is the first study to evaluate the effect of chocolate on arterial elasticity in PLHIV. The results showed that dark chocolate consumption for 15 days improved the elastic properties of the LAEI in PLHIV. These findings, added to the noninvasive method used, may expand the knowledge of CVDs in this population.

Interplay of long-range and short-range Coulomb interactions in an Anderson-Mott insulator

NASA Astrophysics Data System (ADS)

Baćani, Mirko; Novak, Mario; Orbanić, Filip; Prša, Krunoslav; Kokanović, Ivan; Babić, Dinko

2017-07-01

In this paper, we tackle the complexity of coexisting disorder and Coulomb electron-electron interactions (CEEIs) in solids by addressing a strongly disordered system with intricate CEEIs and a screening that changes both with charge carrier doping level Q and temperature T . We report on an experimental comparative study of the T dependencies of the electrical conductivity σ and magnetic susceptibility χ of polyaniline pellets doped with dodecylbenzenesulfonic acid over a wide range. This material is special within the class of doped polyaniline by exhibiting in the electronic transport a crossover between a low-T variable range hopping (VRH) and a high-T nearest-neighbor hopping (NNH) well below room temperature. Moreover, there is evidence of a soft Coulomb gap ΔC in the disorder band, which implies the existence of a long-range CEEI. Simultaneously, there is an onsite CEEI manifested as a Hubbard gap U and originating in the electronic structure of doped polyaniline, which consists of localized electron states with dynamically varying occupancy. Therefore, our samples represent an Anderson-Mott insulator in which long-range and short-range CEEIs coexist. The main result of the study is the presence of a crossover between low- and high-T regimes not only in σ (T ) but also in χ (T ) , the crossover temperature T* being essentially the same for both observables over the entire doping range. The relatively large electron localization length along the polymer chains results in U being small, between 12 and 20 meV for the high and low Q , respectively. Therefore, the thermal energy at T* is sufficiently large to lead to an effective closing of the Hubbard gap and the consequent appearance of NNH in the electronic transport within the disorder band. ΔC is considerably larger than U , decreasing from 190 to 30 meV as Q increases, and plays the role of an activation energy in the NNH.

The Crossover Time as an Evaluation of Ocean Models Against Persistence

NASA Astrophysics Data System (ADS)

Phillipson, L. M.; Toumi, R.

2018-01-01

A new ocean evaluation metric, the crossover time, is defined as the time it takes for a numerical model to equal the performance of persistence. As an example, the average crossover time calculated using the Lagrangian separation distance (the distance between simulated trajectories and observed drifters) for the global MERCATOR ocean model analysis is found to be about 6 days. Conversely, the model forecast has an average crossover time longer than 6 days, suggesting limited skill in Lagrangian predictability by the current generation of global ocean models. The crossover time of the velocity error is less than 3 days, which is similar to the average decorrelation time of the observed drifters. The crossover time is a useful measure to quantify future ocean model improvements.

Heat transport in an anharmonic crystal

NASA Astrophysics Data System (ADS)

Acharya, Shiladitya; Mukherjee, Krishnendu

2018-04-01

We study transport of heat in an ordered, anharmonic crystal in the form of slab geometry in three dimensions. Apart from attaching baths of Langevin type to two extreme surfaces, we also attach baths of same type to the intermediate surfaces of the slab. Since the crystal is uninsulated, it exchanges energy with the intermediate heat baths. We find that both Fourier’s law of heat conduction and the Newton’s law of cooling hold to leading order in anharmonic coupling. The leading behavior of the temperature profile is exponentially falling from high to low temperature surface of the slab. As the anharmonicity increases, profiles fall more below the harmonic one in the log plot. In the thermodynamic limit thermal conductivity remains independent of the environment temperature and its leading order anharmonic contribution is linearly proportional to the temperature change between the two extreme surfaces of the slab. A fast crossover from one-dimensional (1D) to three-dimensional (3D) behavior of the thermal conductivity is observed in the system.

Exposure to bisphenol A from drinking canned beverages increases blood pressure: randomized crossover trial.

PubMed

Bae, Sanghyuk; Hong, Yun-Chul

2015-02-01

Bisphenol A (BPA) is a chemical used in plastic bottles and inner coating of beverage cans, and its exposure is almost ubiquitous. BPA has been associated with hypertension and decreased heart rate variability in the previous studies. The aim of the present study was to determine whether increased BPA exposure from consumption of canned beverage actually affects blood pressure and heart rate variability. We conducted a randomized crossover trial with noninstitutionalized adults, who were aged ≥60 years and recruited from a local community center. A total of 60 participants visited the study site 3 times, and they were provided the same beverage in 2 glass bottles, 2 cans, or 1 can and 1 glass bottle at a time. The sequence of the beverage was randomized. We then measured urinary BPA concentration, blood pressure, and heart rate variability 2 hours after the consumption of each beverage. The paired t test and mixed model were used to compare the differences. The urinary BPA concentration increased after consuming canned beverages by >1600% compared with that after consuming glass bottled beverages. Systolic blood pressure adjusted for daily variance increased by ≈4.5 mm Hg after consuming 2 canned beverages compared with that after consuming 2 glass bottled beverages, and the difference was statistically significant. The parameters of the heart rate variability did not show statistically significant differences.The present study demonstrated that consuming canned beverage and consequent increase of BPA exposure increase blood pressure acutely. © 2014 American Heart Association, Inc.

A Randomized, Two-Way Crossover Study to Evaluate the Pharmacokinetics of Caffeine Delivered Using Caffeinated Chewing Gum Versus a Marketed Caffeinated Beverage in Healthy Adult Volunteers.

PubMed

Sadek, Paul; Pan, Xiao; Shepherd, Phil; Malandain, Elise; Carney, John; Coleman, Hugh

2017-12-01

Background: This study was conducted to compare the pharmacokinetics of caffeine delivered using caffeinated chewing gum to that delivered using a marketed caffeinated beverage (instant coffee) in 16 healthy adult volunteers. Materials and Methods: This was a controlled open-label, randomized, two-period crossover study. Caffeinated chewing gum and a serving of instant coffee, each containing ∼50 mg caffeine, were administered with blood samples collected before and up to 24 hours after administration starts. Plasma caffeine levels were analyzed using validated liquid chromatography coupled with tandem mass spectrometry methodology. Results: There were no statistical differences between the two caffeine products in t max ( p  = 0.3308) and k a ( p  = 0.3894). Although formulated at ∼50 mg caffeine each, mean dose released from chewing gum was ∼18% less than beverage. Dose-normalized area under the concentration-time curve (AUC) 0-t , AUC 0-∞ , and C max was similar between products. Although the criteria were not set a priori and the study was not powered for concluding bioequivalence, the 90% confidence intervals fell within the bioequivalence limit of 80% to 125%. Conclusions: Existing scientific literature on caffeine, based mostly on data from caffeinated beverages, can be leveraged to support the safety of caffeine delivered by chewing gum and current maximum safe caffeine dose advice should be applicable irrespective of delivery method.

Residual effects of zopiclone 7.5 mg on highway driving performance in insomnia patients and healthy controls: a placebo controlled crossover study.

PubMed

Leufkens, T R M; Ramaekers, J G; de Weerd, A W; Riedel, W J; Vermeeren, A

2014-07-01

Residual effects of hypnotics on driving performance have been mainly determined in studies using a standardized driving test with healthy good sleepers. Responses to effects may differ, however, between insomniacs and healthy volunteers due to the underlying sleep disorder. In addition, a majority of insomniacs uses hypnotics chronically resulting in the development of tolerance to impairing effects. Impaired driving performance in healthy volunteers may then be an overestimation of the actual effects in insomniacs. The present study aims to compare the residual effects of zopiclone 7.5 mg on on-the-road driving performance of 16 middle-aged insomniacs chronically using hypnotics (chronic users), 16 middle-aged insomniacs not or infrequently using hypnotics (infrequent users), and 16 healthy, age matched, good sleepers (controls). The study was conducted according to a 3 × 2 double-blind, placebo controlled crossover design, with three groups and two treatment conditions. Treatments were single oral doses of zopiclone 7.5 mg and placebo administered at bedtime (2330 hours). Between 10 and 11 h after administration subjects performed a standardized highway driving test. Zopiclone 7.5 mg significantly impaired on-the-road driving performance in both insomnia groups and healthy controls. The magnitude of impairment was significantly less in the chronic users group as compared with the controls. The smaller magnitude of effects suggests that investigating residual effects of hypnotics in healthy volunteers may yield a minor overestimation of the actual effects in insomnia patients.

Conductive polymer layers to limit transfer of fuel reactants to catalysts of fuel cells to reduce reactant crossover

DOEpatents

Stanis, Ronald J.; Lambert, Timothy N.

2016-12-06

An apparatus of an aspect includes a fuel cell catalyst layer. The fuel cell catalyst layer is operable to catalyze a reaction involving a fuel reactant. A fuel cell gas diffusion layer is coupled with the fuel cell catalyst layer. The fuel cell gas diffusion layer includes a porous electrically conductive material. The porous electrically conductive material is operable to allow the fuel reactant to transfer through the fuel cell gas diffusion layer to reach the fuel cell catalyst layer. The porous electrically conductive material is also operable to conduct electrons associated with the reaction through the fuel cell gas diffusion layer. An electrically conductive polymer material is coupled with the fuel cell gas diffusion layer. The electrically conductive polymer material is operable to limit transfer of the fuel reactant to the fuel cell catalyst layer.

Evaluation of 5 Hour Energy Drink on the Blood Pressure and Electrocardiograph Parameters on Young Healthy Volunteers: A Randomized, Double Blind, Crossover, Placebo-Controlled Trial

DTIC Science & Technology

2014-02-11

Travis AFB CA INSTITUTIONAL REVIEW BOARD (IRB) ()~\\) Non-Exempt Study Final Report p3YVJ (Please 1J!J!£ all information. Use additional pages if...QTc interval after acute and chronic consumption. METHODS: This was a randomized, placebo controlled, crossover study enrolling young healthy volunteers...not on any medications. Subjects received the study drink (5 Hour Energy shot or placebo) twice daily separated by approximately 7 hours for the

A crossover-crossback prospective study of dibutyl-phthalate exposure from mesalamine medications and semen quality in men with inflammatory bowel disease.

PubMed

Nassan, Feiby L; Coull, Brent A; Skakkebaek, Niels E; Williams, Michelle A; Dadd, Ramace; Mínguez-Alarcón, Lidia; Krawetz, Stephen A; Hait, Elizabeth J; Korzenik, Joshua R; Moss, Alan C; Ford, Jennifer B; Hauser, Russ

2016-10-01

Phthalates are widely used chemicals with ubiquitous exposure. Dibutyl-phthalate (DBP), a male reproductive toxicant in animals, is understudied in humans. Some mesalamine medications used to treat inflammatory bowel disease (IBD) have DBP in their coating, whereas other mesalamine formulations do not. Taking advantage of differences in mesalamine formulations, we investigated whether high-DBP exposure from mesalamine medications was associated with decreased semen parameters. 73 men with IBD taking mesalamine participated in a crossover-crossback prospective study. Men taking non-DBP containing mesalamine at baseline i.e., background exposure, crossed-over for four months to high-DBP mesalamine and then crossed-back for four months to their non-DBP mesalamine (B1HB2-arm;Background1-High-Background2) and vice versa for men taking high-DBP mesalamine at baseline (H1BH2-arm;High1-Background-High2). Men provided up to six semen samples (2: baseline, 2: crossover and 2: crossback). We estimated crossover, crossback and carryover effects using linear mixed models adjusted for abstinence time, age, season and duration on high-DBP mesalamine at baseline. Semen parameters in B1HB2-arm (26 men, 133 samples) decreased after high-DBP mesalamine exposure (crossover versus baseline), especially motility parameters, and continued to decrease further even after crossback to non-DBP mesalamine (crossback versus crossover). The cumulative carryover effect of high-DBP (crossback versus baseline) was a decrease of % total sperm motility by 7.61(CI:-13.1, -2.15), % progressive sperm motility by 4.23(CI:-8.05, -0.4) and motile sperm count by 26.0% (CI:-46.2%, 1.7%). However, H1BH2-arm (47 men, 199 samples) had no significant change during crossover or crossback. Men newly exposed to high-DBP mesalamine for four months had a cumulative reduction in several semen parameters, primarily sperm motility, that was more pronounced and statistically significant even after exposure ended for four months. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ultrafast terahertz spectroscopy study of a Kondo insulating thin-film Sm B6 : Evidence for an emergent surface state

NASA Astrophysics Data System (ADS)

Zhang, Jingdi; Yong, Jie; Takeuchi, Ichiro; Greene, Richard L.; Averitt, Richard D.

2018-04-01

We utilize terahertz time domain spectroscopy to investigate thin films of the heavy fermion compound Sm B6 , a prototype Kondo insulator. Temperature-dependent terahertz (THz) conductivity measurements reveal a rapid decrease in the Drude weight and carrier scattering rate at ˜T*=20 K , well below the hybridization gap onset temperature (100 K). Moreover, a low-temperature conductivity plateau (below 20 K) suggests the emergence of a surface state with an effective electron mass of 0.1 me . The conductivity dynamics following optical excitation is also measured and interpreted using Rothwarf-Taylor (R-T) phenomenology, yielding a hybridization gap energy of 17 meV. However, R-T modeling of the conductivity dynamics reveals a deviation from the expected thermally excited quasiparticle density at temperatures below 20 K, indicative of another channel opening up in the low-energy electrodynamics. Taken together, these results are consistent with the onset of a surface state well below the crossover temperature (100 K) after long-range coherence of the f -electron Kondo lattice is established.

Rhombic-Shaped Nanostructures and Mechanical Properties of 2D DNA Origami Constructed with Different Crossover/Nick Designs.

PubMed

Ma, Zhipeng; Huang, Yunfei; Park, Seongsu; Kawai, Kentaro; Kim, Do-Nyun; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Yamada, Hirofumi; Tabata, Osamu

2018-01-01

DNA origami methods enable the fabrication of various nanostructures and nanodevices, but their effective use depends on an understanding of their structural and mechanical properties and the effects of basic structural features. Frequency-modulation atomic force microscopy is introduced to directly characterize, in aqueous solution, the crossover regions of sets of 2D DNA origami based on different crossover/nick designs. Rhombic-shaped nanostructures formed under the influence of flexible crossovers placed between DNA helices are observed in DNA origami incorporating crossovers every 3, 4, or 6 DNA turns. The bending rigidity of crossovers is determined to be only one-third of that of the DNA helix, based on interhelical electrostatic forces reported elsewhere, and the measured pitches of the 3-turn crossover design rhombic-shaped nanostructures undergoing negligible bending. To evaluate the robustness of their structural integrity, they are intentionally and simultaneously stressed using force-controlled atomic force microscopy. DNA crossovers are verified to have a stabilizing effect on the structural robustness, while the nicks have an opposite effect. The structural and mechanical properties of DNA origami and the effects of crossovers and nicks revealed in this paper can provide information essential for the design of versatile DNA origami structures that exhibit specified and desirable properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

49 CFR 213.353 - Turnouts, crossovers, and lift rail assemblies or other transition devices on moveable bridges.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Turnouts, crossovers, and lift rail assemblies or... SAFETY STANDARDS Train Operations at Track Classes 6 and Higher § 213.353 Turnouts, crossovers, and lift... shall be at least 11/2 inches wide. (d) For all turnouts and crossovers, and lift rail assemblies or...

49 CFR 213.353 - Turnouts, crossovers, and lift rail assemblies or other transition devices on moveable bridges.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Turnouts, crossovers, and lift rail assemblies or... SAFETY STANDARDS Train Operations at Track Classes 6 and Higher § 213.353 Turnouts, crossovers, and lift... shall be at least 11/2 inches wide. (d) For all turnouts and crossovers, and lift rail assemblies or...

How Crossover Speeds up Building Block Assembly in Genetic Algorithms.

PubMed

Sudholt, Dirk

2017-01-01

We reinvestigate a fundamental question: How effective is crossover in genetic algorithms in combining building blocks of good solutions? Although this has been discussed controversially for decades, we are still lacking a rigorous and intuitive answer. We provide such answers for royal road functions and OneMax, where every bit is a building block. For the latter, we show that using crossover makes every ([Formula: see text]+[Formula: see text]) genetic algorithm at least twice as fast as the fastest evolutionary algorithm using only standard bit mutation, up to small-order terms and for moderate [Formula: see text] and [Formula: see text]. Crossover is beneficial because it can capitalize on mutations that have both beneficial and disruptive effects on building blocks: crossover is able to repair the disruptive effects of mutation in later generations. Compared to mutation-based evolutionary algorithms, this makes multibit mutations more useful. Introducing crossover changes the optimal mutation rate on OneMax from [Formula: see text] to [Formula: see text]. This holds both for uniform crossover and k-point crossover. Experiments and statistical tests confirm that our findings apply to a broad class of building block functions.

The kinetochore prevents centromere-proximal crossover recombination during meiosis

PubMed Central

Vincenten, Nadine; Kuhl, Lisa-Marie; Lam, Isabel; Oke, Ashwini; Kerr, Alastair RW; Hochwagen, Andreas; Fung, Jennifer; Keeney, Scott; Vader, Gerben; Marston, Adèle L

2015-01-01

During meiosis, crossover recombination is essential to link homologous chromosomes and drive faithful chromosome segregation. Crossover recombination is non-random across the genome, and centromere-proximal crossovers are associated with an increased risk of aneuploidy, including Trisomy 21 in humans. Here, we identify the conserved Ctf19/CCAN kinetochore sub-complex as a major factor that minimizes potentially deleterious centromere-proximal crossovers in budding yeast. We uncover multi-layered suppression of pericentromeric recombination by the Ctf19 complex, operating across distinct chromosomal distances. The Ctf19 complex prevents meiotic DNA break formation, the initiating event of recombination, proximal to the centromere. The Ctf19 complex independently drives the enrichment of cohesin throughout the broader pericentromere to suppress crossovers, but not DNA breaks. This non-canonical role of the kinetochore in defining a chromosome domain that is refractory to crossovers adds a new layer of functionality by which the kinetochore prevents the incidence of chromosome segregation errors that generate aneuploid gametes. DOI: http://dx.doi.org/10.7554/eLife.10850.001 PMID:26653857

Magnetization reversal dynamics in Co nanowires with competing magnetic anisotropies

NASA Astrophysics Data System (ADS)

Pal, Semanti; Saha, Susmita; Polley, Debanjan; Barman, Anjan

2011-12-01

We present the magnetization reversal dynamics of Co nanowires with competing magnetic anisotropies. The aspect ratio ( R) of the nanowires is varied between 2.5 and 60, and we observe a cross-over of the directions of the magnetic easy and hard axes at R=6.8. Micromagnetic simulations qualitatively reproduce the observed cross-over and give detailed insight into the reversal mechanisms associated with the cross-over. The reversal mechanism for a field applied along the long axis of the nanowire exhibits a quasi-coherent rotation mode and a corkscrew-like mode, respectively, above and below the cross-over, with the formation of a Bloch domain near the cross-over region. For a field applied along the short axis, the reversal occurs by nucleation and propagation of reversed domains from the two ends of the nanowires for very high values of the aspect ratio down to the cross-over region, but it transforms into quasi-coherent rotation mode for smaller aspect ratios (below the cross-over region).

Medication use and the risk of motor vehicle collision in West Virginia drivers 65 years of age and older: a case-crossover study.

PubMed

Rudisill, Toni M; Zhu, Motao; Davidov, Danielle; Leann Long, D; Sambamoorthi, Usha; Abate, Marie; Delagarza, Vincent

2016-03-15

The current generation of older adults reports a higher lifetime prevalence of prescription, over-the-counter, and recreational drug use. The purpose of this analysis is to characterize the drug usage and determine the risk of motor vehicle collision associated with individual medications in a population of drivers ≥ 65 years. A case-crossover study was conducted at West Virginia University Healthcare's facilities using data obtained from the electronic health records (n = 611) of drivers ≥ 65 years admitted for medical treatment following a motor vehicle collision which occurred between Jan. 1, 2009 and June 30, 2014. Patients' medication usage 14 days before collision were matched and compared to their medication usage during four control periods prior to collision. Odds ratios were then calculated for the most prevalent individual medications and pharmaceutical sub-classes using conditional logistic regression. Analgesic, cardiovascular and gastrointestinal medicines were common. Few drivers tested positive for either licit or illicit drugs. Of those testing positive for drugs, benzodiazepines and opiates were prevalent. Drivers consuming Tramadol (adjusted OR 11.41; 95% CI 1.27, 102.15) were at a significantly increased risk of motor vehicle collision. Older adult drivers who have a prescription for this medication may need to be aware of the potential risk. Further research is necessary in a larger, more nationally representative population.

The Effect of a 12-Week Beta-hydroxy-beta-methylbutyrate (HMB) Supplementation on Highly-Trained Combat Sports Athletes: A Randomised, Double-Blind, Placebo-Controlled Crossover Study

PubMed Central

Jeszka, Jan; Podgórski, Tomasz

2017-01-01

The aim of this study was to verify the effect of beta-hydroxy-beta-methylbutyrate (HMB) supplementation on physical capacity, body composition and the value of biochemical parameters in highly-trained combat sports athletes. Forty-two males highly-trained in combat sports were subjected to 12 weeks of supplementation with HMB and a placebo in a randomized, placebo controlled, double-blind crossover manner. Over the course of the experiment, aerobic and anaerobic capacity was determined, while analyses were conducted on body composition and levels of creatine kinase, lactate dehydrogenase, testosterone, cortisol and lactate. Following HMB supplementation, fat-free mass increased (p = 0.049) with a simultaneous reduction of fat mass (p = 0.016) in comparison to placebo. In turn, after HMB supplementation, the following indicators increased significantly in comparison to the placebo: the time to reach ventilatory threshold (p < 0.0001), threshold load (p = 0.017) and the threshold HR (p < 0.0001), as well as anaerobic peak power (p = 0.005), average power (p = 0.029), maximum speed (p < 0.001) and post-exercise lactate concentrations (p < 0.0001). However, when compared to the placebo, no differences were observed in blood marker levels. The results indicate that supplying HMB promotes advantageous changes in body composition and stimulates an increase in aerobic and anaerobic capacity in combat sports athletes. PMID:28708126

The Effect of a 12-Week Beta-hydroxy-beta-methylbutyrate (HMB) Supplementation on Highly-Trained Combat Sports Athletes: A Randomised, Double-Blind, Placebo-Controlled Crossover Study.

PubMed

Durkalec-Michalski, Krzysztof; Jeszka, Jan; Podgórski, Tomasz

2017-07-14

The aim of this study was to verify the effect of beta-hydroxy-beta-methylbutyrate (HMB) supplementation on physical capacity, body composition and the value of biochemical parameters in highly-trained combat sports athletes. Forty-two males highly-trained in combat sports were subjected to 12 weeks of supplementation with HMB and a placebo in a randomized, placebo controlled, double-blind crossover manner. Over the course of the experiment, aerobic and anaerobic capacity was determined, while analyses were conducted on body composition and levels of creatine kinase, lactate dehydrogenase, testosterone, cortisol and lactate. Following HMB supplementation, fat-free mass increased ( p = 0.049) with a simultaneous reduction of fat mass ( p = 0.016) in comparison to placebo. In turn, after HMB supplementation, the following indicators increased significantly in comparison to the placebo: the time to reach ventilatory threshold ( p < 0.0001), threshold load ( p = 0.017) and the threshold HR ( p < 0.0001), as well as anaerobic peak power ( p = 0.005), average power ( p = 0.029), maximum speed ( p < 0.001) and post-exercise lactate concentrations ( p < 0.0001). However, when compared to the placebo, no differences were observed in blood marker levels. The results indicate that supplying HMB promotes advantageous changes in body composition and stimulates an increase in aerobic and anaerobic capacity in combat sports athletes.

Work-Family Conflict within the Family: Crossover Effects, Perceived Parent-Child Interaction Quality, Parental Self-Efficacy, and Life Role Attributions

ERIC Educational Resources Information Center

Cinamon, Rachel Gali; Weisel, Amatzia; Tzuk, Kineret

2007-01-01

To better understand the work-family interface within the family domain, this study investigated crossover effects of two types of work-family conflict among 120 participants (60 married couples), these conflicts' relations with parental self-efficacy and perceived quality of parent-child interaction, and the contribution of attributions of…

Case-crossover design and its implementation in R

PubMed Central

2016-01-01

Case-crossover design is a variation of case-control design that it employs persons’ history periods as controls. Case-crossover design can be viewed as the hybrid of case-control study and crossover design. Characteristic confounding that is constant within one person can be well controlled with this method. The relative risk and odds ratio, as well as their 95% confidence intervals (CIs), can be estimated using Cochran-Mantel-Haenszel method. R codes for the calculation are provided in the main text. Readers may adapt these codes to their own task. Conditional logistic regression model is another way to estimate odds ratio of the exposure. Furthermore, it allows for incorporation of other time-varying covariates that are not constant within subjects. The model fitting per se is not technically difficult because there is well developed statistical package. However, it is challenging to convert original dataset obtained from case report form to that suitable to be passed to clogit() function. R code for this task is provided and explained in the text. PMID:27761445

Automatic identification of vessel crossovers in retinal images

NASA Astrophysics Data System (ADS)

Sánchez, L.; Barreira, N.; Penedo, M. G.; Cancela, B.

2015-02-01

Crossovers and bifurcations are interest points of the retinal vascular tree useful to diagnose diseases. Specifically, detecting these interest points and identifying which of them are crossings will give us the opportunity to search for arteriovenous nicking, this is, an alteration of the vessel tree where an artery is crossed by a vein and the former compresses the later. These formations are a clear indicative of hypertension, among other medical problems. There are several studies that have attempted to define an accurate and reliable method to detect and classify these relevant points. In this article, we propose a new method to identify crossovers. Our approach is based on segmenting the vascular tree and analyzing the surrounding area of each interest point. The minimal path between vessel points in this area is computed in order to identify the connected vessel segments and, as a result, to distinguish between bifurcations and crossovers. Our method was tested using retinographies from public databases DRIVE and VICAVR, obtaining an accuracy of 90%.

Kinetic roughening and porosity scaling in film growth with subsurface lateral aggregation.

PubMed

Reis, F D A Aarão

2015-06-01

We study surface and bulk properties of porous films produced by a model in which particles incide perpendicularly to a substrate, interact with deposited neighbors in its trajectory, and aggregate laterally with probability of order a at each position. The model generalizes ballisticlike models by allowing attachment to particles below the outer surface. For small values of a, a crossover from uncorrelated deposition (UD) to correlated growth is observed. Simulations are performed in 1+1 and 2+1 dimensions. Extrapolation of effective exponents and comparison of roughness distributions confirm Kardar-Parisi-Zhang roughening of the outer surface for a>0. A scaling approach for small a predicts crossover times as a(-2/3) and local height fluctuations as a(-1/3) at the crossover, independent of substrate dimension. These relations are different from all previously studied models with crossovers from UD to correlated growth due to subsurface aggregation, which reduces scaling exponents. The same approach predicts the porosity and average pore height scaling as a(1/3) and a(-1/3), respectively, in good agreement with simulation results in 1+1 and 2+1 dimensions. These results may be useful for modeling samples with desired porosity and long pores.

Chiral crossover transition in a finite volume

NASA Astrophysics Data System (ADS)

Shi, Chao; Jia, Wenbao; Sun, An; Zhang, Liping; Zong, Hongshi

2018-02-01

Finite volume effects on the chiral crossover transition of strong interactions at finite temperature are studied by solving the quark gap equation within a cubic volume of finite size L. With the anti-periodic boundary condition, our calculation shows the chiral quark condensate, which characterizes the strength of dynamical chiral symmetry breaking, decreases as L decreases below 2.5 fm. We further study the finite volume effects on the pseudo-transition temperature {T}{{c}} of the crossover, showing a significant decrease in {T}{{c}} as L decreases below 3 fm. Supported by National Natural Science Foundation of China (11475085, 11535005, 11690030, 51405027), the Fundamental Research Funds for the Central Universities (020414380074), China Postdoctoral Science Foundation (2016M591808) and Open Research Foundation of State Key Lab. of Digital Manufacturing Equipment & Technology in Huazhong University of Science & Technology (DMETKF2015015)

Computer Analysis of 400 HZ Aircraft Electrical Generator Test Data.

DTIC Science & Technology

1980-06-01

Data Acquisition System. ............ 6 3 Voltage Waveform with Data Points. ....... 19 14 Zero Crossover Interpolation. ........ 20 5 Numerical...difference between successive positive-sloped zero crossovers of the waveform. However, the exact time of zero crossover is not known. This is because...data sampling and the generator output are not synchronized. This unsynchronization means that data points which correspond with an exact zero crossover

Interim analyses in 2 x 2 crossover trials.

PubMed

Cook, R J

1995-09-01

A method is presented for performing interim analyses in long term 2 x 2 crossover trials with serial patient entry. The analyses are based on a linear statistic that combines data from individuals observed for one treatment period with data from individuals observed for both periods. The coefficients in this linear combination can be chosen quite arbitrarily, but we focus on variance-based weights to maximize power for tests regarding direct treatment effects. The type I error rate of this procedure is controlled by utilizing the joint distribution of the linear statistics over analysis stages. Methods for performing power and sample size calculations are indicated. A two-stage sequential design involving simultaneous patient entry and a single between-period interim analysis is considered in detail. The power and average number of measurements required for this design are compared to those of the usual crossover trial. The results indicate that, while there is minimal loss in power relative to the usual crossover design in the absence of differential carry-over effects, the proposed design can have substantially greater power when differential carry-over effects are present. The two-stage crossover design can also lead to more economical studies in terms of the expected number of measurements required, due to the potential for early stopping. Attention is directed toward normally distributed responses.

Dynamic crossover in deeply cooled water confined in MCM-41 at 4 kbar and its relation to the liquid-liquid transition hypothesis

NASA Astrophysics Data System (ADS)

Wang, Zhe; Le, Peisi; Ito, Kanae; Leão, Juscelino B.; Tyagi, Madhusudan; Chen, Sow-Hsin

2015-09-01

With quasi-elastic neutron scattering, we study the single-particle dynamics of the water confined in a hydrophilic silica material, MCM-41, at 4 kbar. A dynamic crossover phenomenon is observed at 219 K. We compare this dynamic crossover with the one observed at ambient pressure and find that (a) above the crossover temperature, the temperature dependence of the characteristic relaxation time at ambient pressure exhibits a more evident super-Arrhenius behavior than that at 4 kbar. Especially, at temperatures below about 230 K, the relaxation time at 4 kbar is even smaller than that at ambient pressure. This feature is different from many other liquids. (b) Below the crossover temperature, the Arrhenius behavior found at ambient pressure has a larger activation energy compared to the one found at 4 kbar. We ascribe the former to the difference between the local structure of the low-density liquid (LDL) phase and that of the high-density liquid (HDL) phase, and the latter to the difference between the strength of the hydrogen bond of the LDL and that of the HDL. Therefore, we conclude that the phenomena observed in this paper are consistent with the LDL-to-HDL liquid-liquid transition hypothesis.

Dynamic crossover in deeply cooled water confined in MCM-41 at 4 kbar and its relation to the liquid-liquid transition hypothesis

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

Wang, Zhe; Le, Peisi; Ito, Kanae

With quasi-elastic neutron scattering, we study the single-particle dynamics of the water confined in a hydrophilic silica material, MCM-41, at 4 kbar. A dynamic crossover phenomenon is observed at 219 K. We compare this dynamic crossover with the one observed at ambient pressure and find that (a) above the crossover temperature, the temperature dependence of the characteristic relaxation time at ambient pressure exhibits a more evident super-Arrhenius behavior than that at 4 kbar. Especially, at temperatures below about 230 K, the relaxation time at 4 kbar is even smaller than that at ambient pressure. This feature is different from manymore » other liquids. (b) Below the crossover temperature, the Arrhenius behavior found at ambient pressure has a larger activation energy compared to the one found at 4 kbar. We ascribe the former to the difference between the local structure of the low-density liquid (LDL) phase and that of the high-density liquid (HDL) phase, and the latter to the difference between the strength of the hydrogen bond of the LDL and that of the HDL. Therefore, we conclude that the phenomena observed in this paper are consistent with the LDL-to-HDL liquid-liquid transition hypothesis.« less

Effects of sitagliptin on counter-regulatory and incretin hormones during acute hypoglycaemia in patients with type 1 diabetes: a randomized double-blind placebo-controlled crossover study.

PubMed

Schopman, J E; Hoekstra, J B L; Frier, B M; Ackermans, M T; de Sonnaville, J J J; Stades, A M; Zwertbroek, R; Hartmann, B; Holst, J J; Knop, F K; Holleman, F

2015-06-01

To assess whether the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin affects glucagon and other counter-regulatory hormone responses to hypoglycaemia in patients with type 1 diabetes. We conducted a single-centre, randomized, double-blind, placebo-controlled, three-period crossover study. We studied 16 male patients with type 1 diabetes aged 18-52 years, with a diabetes duration of 5-20 years and intact hypoglycaemia awareness. Participants received sitagliptin (100 mg/day) or placebo for 6 weeks and attended the hospital for three acute hypoglycaemia studies (at baseline, after sitagliptin treatment and after placebo). The primary outcome was differences between the three hypoglycaemia study days with respect to plasma glucagon responses from the initialization phase of the hypoglycaemia intervention to 40 min after onset of the autonomic reaction. Sitagliptin treatment significantly increased active levels of glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1. No significant differences were observed for glucagon or adrenergic counter-regulatory responses during the three hypoglycaemia studies. Growth hormone concentration at 40 min after occurrence of autonomic reaction was significantly lower after sitagliptin treatment [median (IQR) 23 (0.2-211.0) mEq/l] compared with placebo [median (IQR) 90 (8.8-180) mEq/l; p = 0.008]. Sitagliptin does not affect glucagon or adrenergic counter-regulatory responses in patients with type 1 diabetes, but attenuates the growth hormone response during late hypoglycaemia. © 2015 John Wiley & Sons Ltd.

Hesperidin contributes to the vascular protective effects of orange juice: a randomized crossover study in healthy volunteers.

PubMed

Morand, Christine; Dubray, Claude; Milenkovic, Dragan; Lioger, Delphine; Martin, Jean François; Scalbert, Augustin; Mazur, Andrzej

2011-01-01

Although numerous human studies have shown consistent effects of some polyphenol-rich foods on several intermediate markers for cardiovascular diseases, it is still unknown whether their action could be specifically related to polyphenols. We investigated the effect of orange juice and its major flavonoid, hesperidin, on microvascular reactivity, blood pressure, and cardiovascular risk biomarkers through both postprandial and chronic intervention studies. Twenty-four healthy, overweight men (age 50-65 y) were included in a randomized, controlled, crossover study. Throughout the three 4-wk periods, volunteers daily consumed 500 mL orange juice, 500 mL control drink plus hesperidin (CDH), or 500 mL control drink plus placebo (CDP). All measurements and blood collections were performed in overnight-fasted subjects before and after the 4-wk treatment periods. The postprandial study was conducted at the beginning of each experimental period. Diastolic blood pressure (DBP) was significantly lower after 4 wk consumption of orange juice or CDH than after consumption of CDP (P = 0.02), whereas microvascular endothelium-related reactivity was not significantly affected when measured after an overnight fast. However, both orange juice and CDH ingestion significantly improved postprandial microvascular endothelial reactivity compared with CDP (P < 0.05) when measured at the peak of plasma hesperetin concentration. In healthy, middle-aged, moderately overweight men, orange juice decreases DBP when regularly consumed and postprandially increases endothelium-dependent microvascular reactivity. Our study suggests that hesperidin could be causally linked to the beneficial effect of orange juice. This trial is registered at clinicaltrials.gov as NCT00983086.

Does a crossover age effect exist for African American and Hispanic binge drinkers? Findings from the 2010-2013 National Study on Drug Use and Health

PubMed Central

Zapolski, Tamika C. B.; Baldwin, Patrick; Banks, Devin E.; Stump, Timothy E.

2017-01-01

Background Among general population studies, lower rates of binge drinking tend to be found among African Americans and Hispanics compared to Whites. However, among older adult populations, minority groups have been shown to be at higher risk for binge drinking, suggesting the presence of a crossover effect from low to high risk as a function of age. Aims To date, limited research has examined the crossover effect among African American and Hispanic populations compared to non-Hispanic Whites across large developmental time frames or explored variation in risk based on income or gender. The current study aimed to fill these gaps in the literature. Methods Data were compiled from the 2010-2013 National Survey on Drug Use and Health surveys, which provide annual, nationally representative data on substance use behaviors among individuals age 12 and older. Hispanic, non-Hispanic African American, and non-Hispanic White respondents were included (N = 205,198) in the analyses. Results A crossover effect was found for African American males and females among the lowest income level (i.e., incomes less than $20,000). Specifically, after controlling for education and marital status, compared to Whites, risk for binge drinking was lower for African American males at ages 18-24 and for females at ages 18-34, but higher for both African American males and females at ages 50 to 64. No crossover effect was found for Hispanic respondents. Conclusions Although African Americans are generally at lower risk for binge drinking, risk appears to increase disproportionately with age among those who are impoverished. Social determinants of health prevalent within low-income African American communities (e.g., lower education, violence exposure, housing insecurity) and potential areas for intervention programming are discussed. PMID:28423479

Anti-mite measurements in mite-sensitive adult asthma. A controlled trial.

PubMed

Burr, M L; St Leger, A S; Neale, E

1976-02-14

A cross-over controlled trial has been conducted among 32 adult patients with mite-sensitive asthma. The bedclothes and pillows of each subject were laundered and vacuum-cleaned and a plastic cover applied to the mattress for six weeks in an attempt to reduce exposure to mites. No improvement in daily peak-flow reading or drug usage was found in comparison with a control period.

Development of Driver/Vehicle Steering Interaction Models for Dynamic Analysis

DTIC Science & Technology

1988-12-01

Figure 5-10. The Linearized Single-Unit Vehicle Model ............................... 41 Figure 5-11. Interpretation of the Single-Unit Model...The starting point for the driver modelling research conducted under this project was a linear preview control model originally proposed by MacAdam 1...regardless of its origin, can pass at least the elementary validation test of exhibiting "cross-over model"-like- behavior in the vicinity of its

Mechanism of ultrasonic energy-assisted formation of V-, Y-shaped nano-structures in conjugated polymers.

PubMed

Majumdar, D; Maiti, R P; Basu, S; Saha, S K

2009-12-01

Recently, hydrocarbon-nanostructures from organic solvent using ultrasonic energy were reported. However, their formation-dynamics remained unexplored. Here, we describe a new technique to synthesize controlled nanostructures (V-, Y-shape) from nanorods of conducting polyaniline applying ultrasonic energy. To characterize the conducting state (emaraldine) of these polyaniline nanorods, electrical measurements have been carried out from which it is seen that there is a crossover from metallic to semiconductor as temperature increases. The observed crossover has been explained by the core-shell structure of the nanorods with core resistivity much higher than the shell resistivity. The nonlinear current-voltage behavior is attributed to the formation of alternate ordered/disordered chain segments along the length of the nanorods. We also propose a model to explore the mechanism of formation of these V-, Y-shaped nanostructures. It is believed that bubble-formation occurs in liquid due to ultrasonic vibration; and asymmetry in the bubble is created when formed near the solid surface leading to jet formation. Liquid jets of collapsing bubble move with incredible velocity (400 km/h); collide with the nanorod to cause fragmentations followed by V-, Y-shaped structure formation when the imparted kinetic energy of jets is comparable with elastic energy of fragments.

Dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate

NASA Astrophysics Data System (ADS)

Pal, P.; Ghosh, A.

2016-07-01

In this paper, we have studied the dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate. Structural and thermal properties have been examined using X-ray diffraction and differential scanning calorimetry, respectively. We have analyzed the complex conductivity spectra by using power law model coupled with the contribution of electrode polarization at low frequencies and high temperatures. The temperature dependence of the ionic conductivity and crossover frequency exhibits Vogel-Tammann-Fulcher type behavior indicating a strong coupling between the ionic and the polymer chain segmental motions. The scaling of the ac conductivity indicates that relaxation dynamics of charge carriers follows a common mechanism for all temperatures and ethylene carbonate concentrations. The analysis of the ac conductivity also shows the existence of a nearly constant loss in these polymer electrolytes at low temperatures and high frequencies. The fraction of free anions and ion pairs in polymer electrolyte have been obtained from the analysis of Fourier transform infrared spectra. It is observed that these quantities influence the behavior of the composition dependence of the ionic conductivity.

Dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate

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

Pal, P.; Ghosh, A., E-mail: sspag@iacs.res.in

2016-07-28

In this paper, we have studied the dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate. Structural and thermal properties have been examined using X-ray diffraction and differential scanning calorimetry, respectively. We have analyzed the complex conductivity spectra by using power law model coupled with the contribution of electrode polarization at low frequencies and high temperatures. The temperature dependence of the ionic conductivity and crossover frequency exhibits Vogel-Tammann-Fulcher type behavior indicating a strong coupling between the ionic and the polymer chain segmental motions. The scaling of the ac conductivity indicates that relaxation dynamicsmore » of charge carriers follows a common mechanism for all temperatures and ethylene carbonate concentrations. The analysis of the ac conductivity also shows the existence of a nearly constant loss in these polymer electrolytes at low temperatures and high frequencies. The fraction of free anions and ion pairs in polymer electrolyte have been obtained from the analysis of Fourier transform infrared spectra. It is observed that these quantities influence the behavior of the composition dependence of the ionic conductivity.« less

Calorimetric indications of a cooperativity onset in the crossover region of dynamic glass transition for benzoin isobutylether

NASA Astrophysics Data System (ADS)

Kahle, S.; Schröter, K.; Hempel, E.; Donth, E.

1999-10-01

Heat capacity spectroscopy (HCS), dielectric spectroscopy, and shear viscosity data are reported for liquid benzoin isobutylether (BIBE). Dielectric and viscosity peculiarities indicate the crossover region of dynamic glass transition at T=(-8±8) °C where the extrapolated Johari Goldstein β relaxation intersects the main transition trace in an Arrhenius plot. Although HCS does not reach the crossover frequency of order ω=2×106 rad/s, the linear decrease of the square root of cooperativity as calculated from HCS data at lower frequencies indicates a cooperativity onset in the crossover temperature-frequency range. As BIBE belongs to another dielectric crossover scenario as the substances where such an onset could previously be observed, it seems that the cooperativity onset is a general property of the crossover region.

Polaron physics and crossover transition in magnetite probed by pressure-dependent infrared spectroscopy.

PubMed

Ebad-Allah, J; Baldassarre, L; Sing, M; Claessen, R; Brabers, V A M; Kuntscher, C A

2013-01-23

The optical properties of magnetite at room temperature were studied by infrared reflectivity measurements as a function of pressure up to 8 GPa. The optical conductivity spectrum consists of a Drude term, two sharp phonon modes, a far-infrared band at around 600 cm(-1) and a pronounced mid-infrared absorption band. With increasing pressure both absorption bands shift to lower frequencies and the phonon modes harden in a linear fashion. Based on the shape of the MIR band, the temperature dependence of the dc transport data, and the occurrence of the far-infrared band in the optical conductivity spectrum, the polaronic coupling strength in magnetite at room temperature should be classified as intermediate. For the lower energy phonon mode an abrupt increase of the linear pressure coefficient occurs at around 6 GPa, which could be attributed to minor alterations of the charge distribution among the different Fe sites.

Integrating In Vitro, Modeling, and In Vivo Approaches to Investigate Warfarin Bioequivalence

PubMed Central

Wen, H; Fan, J; Vince, B; Li, T; Gao, W; Kinjo, M; Brown, J; Sun, W; Jiang, W; Lionberger, R

2017-01-01

We demonstrate the use of modeling and simulation to investigate bioequivalence (BE) concerns raised about generic warfarin products. To test the hypothesis that the loss of isopropyl alcohol and slow dissolution in acidic pH has significant impact on the pharmacokinetics of warfarin sodium tablets, we conducted physiologically based pharmacokinetic absorption modeling and simulation using formulation factors or in vitro dissolution profiles as input parameters. Sensitivity analyses indicated that warfarin pharmacokinetics was not sensitive to solubility, particle size, density, or dissolution rate in pH 4.5, but was affected by dissolution rate in pH 6.8 and potency. Virtual BE studies suggested that stressed warfarin sodium tablets with slow dissolution rate in pH 4.5 but having similar dissolution rate in pH 6.8 would be bioequivalent to the unstressed warfarin sodium tablets. A four‐way, crossover, single‐dose BE study in healthy subjects was conducted to test the same hypothesis and confirmed the simulation conclusion. PMID:28379643

Effect of heat exposure and exercise on food intake regulation: A randomized crossover study in young healthy men.

PubMed

Faure, Cécile; Charlot, Keyne; Henri, Stéphane; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Antoine-Jonville, Sophie

2016-10-01

The effect of physical activity on food intake regulation may be moderated by environmental temperature. The aim of the study was to determine the single and combined effects of metabolic activity and temperature on energy intake and its hormonal regulation. A randomized crossover study was conducted in the laboratory. Ten healthy and physically active young Afro-Caribbean men participated in four experimental sessions (rest at 22°C and 31°C and cycling at 60% of their maximal oxygen uptake at 22°C and 31°C, all for 40 min). Each test period was followed by a 30-min recovery period and then an ad libitum meal. The main outcome measures were energy balance, subjective appetite, and plasma pancreatic polypeptide (PP), cholecystokinin (CCK) and ghrelin concentrations. Relative energy intake was significantly decreased whereas plasma PP was increased in the exercise conditions (p=0.004 and p=0.002, respectively). Postprandial levels of CCK were elevated only in the rest conditions. Exposure to heat induced a decrease in plasma ghrelin (p=0.031). Exercise induced a short-term energy deficit. However, modifications in the hormonal regulation of food intake in response to short-term heat or heat and exercise exposure seem to be minor and did not induce changes in energy intake. This trial was registered at clinicaltrials.gov as NCT02157233. Copyright © 2016. Published by Elsevier Inc.

Comparing the Effects of Oral Contraceptives Containing Levonorgestrel With Products Containing Antiandrogenic Progestins on Clinical, Hormonal, and Metabolic Parameters and Quality of Life in Women With Polycystic Ovary Syndrome: Crossover Randomized Controlled Trial Protocol

PubMed Central

Amiri, Mina; Nahidi, Fatemeh; Khalili, Davood; Bidhendi-Yarandi, Razieh

2017-01-01

Background Oral contraceptives (OCs) have been used as a first-line option for medical treatment in women with polycystic ovary syndrome (PCOS). Despite theoretical superiority of products containing antiandrogenic progestins compared to OCs containing levonorgestrel (LNG), the clinical advantage of these compounds remains unclear. Objective The aim of this study was to compare the effects of OCs containing LNG with products containing antiandrogenic progestins including cyproterone acetate, drospirenone, and desogestrel on clinical, hormonal, and metabolic parameters and quality of life in women with PCOS. Methods We conducted a 6-arm crossover randomized controlled trial with each arm including OCs containing LNG and one of those 3 OCs containing antiandrogenic progestins. The anthropometric and clinical manifestations and hormonal and biochemical parameters of participants were assessed at 6 time points including baseline, after washout period, and 3 and 6 months after intervention. Results The study is ongoing and follow-up of recruited women will continue until 2018. Conclusions This study will provide scientific evidence on comparability of OCs with the various progesterones that will assist in decision making taking into account cost effectiveness. Trial Registration Iranian Registry of Clinical Trials IRCT201702071281N2; http://www.irct.ir/searchresult.php? keyword=&id=1281&number=2&prt=12869&total=10&m=1 (Archived by WebCite at http://www.webcitation.org/6tSP8FNWo) PMID:28963092

Randomized Crossover Study of the Natural Restorative Environment Intervention to Improve Attention and Mood in Heart Failure.

PubMed

Jung, Miyeon; Jonides, John; Northouse, Laurel; Berman, Marc G; Koelling, Todd M; Pressler, Susan J

In heart failure (HF), attention may be decreased because of lowered cerebral blood flow and increased attentional demands needed for self-care. Guided by the Attention Restoration Theory, the objective was to test the efficacy of the natural restorative environment (NRE) intervention on improving attention and mood among HF patients and healthy adults. A randomized crossover pilot study was conducted among 20 HF patients and an age- and education-matched comparison group of 20 healthy adults to test the efficacy of the NRE intervention compared with an active control intervention. Neuropsychological tests were administered to examine attention, particularly attention span, sustained attention, directed attention, and attention switching, at before and after the intervention. Mood was measured with the Positive and Negative Affect Schedule. No significant differences were found in attention and mood after the NRE intervention compared with the control intervention among the HF patients and the healthy adults. In analyses with HF patients and healthy adults combined (n = 40), significant differences were found. Compared with the control intervention, sustained attention improved after the NRE intervention (P = .001) regardless of the presence of HF. Compared with the healthy adults, HF patients performed significantly worse on attention switching after the control intervention (P = .045). The NRE intervention may be efficacious in improving sustained attention in HF patients. Future studies are needed to enhance the NRE intervention to be more efficacious and tailored for HF patients and test the efficacy in a larger sample of HF patients.

Circuit Design Optimization Using Genetic Algorithm with Parameterized Uniform Crossover

NASA Astrophysics Data System (ADS)

Bao, Zhiguo; Watanabe, Takahiro

Evolvable hardware (EHW) is a new research field about the use of Evolutionary Algorithms (EAs) to construct electronic systems. EHW refers in a narrow sense to use evolutionary mechanisms as the algorithmic drivers for system design, while in a general sense to the capability of the hardware system to develop and to improve itself. Genetic Algorithm (GA) is one of typical EAs. We propose optimal circuit design by using GA with parameterized uniform crossover (GApuc) and with fitness function composed of circuit complexity, power, and signal delay. Parameterized uniform crossover is much more likely to distribute its disruptive trials in an unbiased manner over larger portions of the space, then it has more exploratory power than one and two-point crossover, so we have more chances of finding better solutions. Its effectiveness is shown by experiments. From the results, we can see that the best elite fitness, the average value of fitness of the correct circuits and the number of the correct circuits of GApuc are better than that of GA with one-point crossover or two-point crossover. The best case of optimal circuits generated by GApuc is 10.18% and 6.08% better in evaluating value than that by GA with one-point crossover and two-point crossover, respectively.

Distinct age and self-rated health crossover mortality effects for African Americans: Evidence from a national cohort study.

PubMed

Roth, David L; Skarupski, Kimberly A; Crews, Deidra C; Howard, Virginia J; Locher, Julie L

2016-05-01

The predictive effects of age and self-rated health (SRH) on all-cause mortality are known to differ across race and ethnic groups. African American adults have higher mortality rates than Whites at younger ages, but this mortality disparity diminishes with advancing age and may "crossover" at about 75-80 years of age, when African Americans may show lower mortality rates. This pattern of findings reflects a lower overall association between age and mortality for African Americans than for Whites, and health-related mechanisms are typically cited as the reason for this age-based crossover mortality effect. However, a lower association between poor SRH and mortality has also been found for African Americans than for Whites, and it is not known if the reduced age and SRH associations with mortality for African Americans reflect independent or overlapping mechanisms. This study examined these two mortality predictors simultaneously in a large epidemiological study of 12,181 African Americans and 17,436 Whites. Participants were 45 or more years of age when they enrolled in the national REasons for Geographic and Racial Differences in Stroke (REGARDS) study between 2003 and 2007. Consistent with previous studies, African Americans had poorer SRH than Whites even after adjusting for demographic and health history covariates. Survival analysis models indicated statistically significant and independent race*age, race*SRH, and age*SRH interaction effects on all-cause mortality over an average 9-year follow-up period. Advanced age and poorer SRH were both weaker mortality risk factors for African Americans than for Whites. These two effects were distinct and presumably tapped different causal mechanisms. This calls into question the health-related explanation for the age-based mortality crossover effect and suggests that other mechanisms, including behavioral, social, and cultural factors, should be considered in efforts to better understand the age-based mortality crossover effect and other longevity disparities. Copyright © 2016. Published by Elsevier Ltd.

Local chromosome context is a major determinant of crossover pathway biochemistry during budding yeast meiosis.

PubMed

Medhi, Darpan; Goldman, Alastair Sh; Lichten, Michael

2016-11-18

The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1 -derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions.

Deep brain stimulation for treatment-resistant major depressive disorder: a comparison of two targets and long-term follow-up

PubMed Central

Raymaekers, S; Luyten, L; Bervoets, C; Gabriëls, L; Nuttin, B

2017-01-01

We previously found that electrical stimulation in the anterior limb of the internal capsule/bed nucleus of the stria terminalis (IC/BST) alleviates depressive symptoms in severe treatment-resistant obsessive-compulsive disorder (OCD) patients. Here we tested the hypothesis that electrical stimulation in either IC/BST or in the inferior thalamic peduncle (ITP) effectively reduces depressive symptoms in treatment-resistant major depressive disorder (TRD). In a double-blind crossover design, the effects of electrical stimulation at both targets were compared in TRD patients. The 17-item Hamilton Depression Rating scale (HAM-D) was the primary outcome measure. During the first crossover, patients received IC/BST stimulation versus no stimulation in random order (2 × 1 weeks). During the second crossover (3 × 2 months), patients received IC/BST versus ITP versus no stimulation. Patients and evaluators were blinded for stimulation conditions. All patients (n=7) were followed up for at least 3 years (3–8 years) after implantation. Six patients completed the first crossover and five patients completed the second. During the first crossover, mean (s.d.) HAM-D scores were 21.5 (2.7) for no stimulation and 11.5 (8.8) for IC/BST stimulation. During the second crossover, HAM-D scores were 15.4 (7.5) for no stimulation, 7.6 (3.8) for IC/BST stimulation and 11.2 (7.5) for ITP stimulation. The final sample size was too small to statistically analyze this second crossover. At last follow-up, only one patient preferred ITP over IC/BST stimulation. Two patients, with a history of suicide attempts before implantation, committed suicide during the follow-up phases of this study. Our data indicate that, in the long term, both ITP and IC/BST stimulation may alleviate depressive symptoms in patients suffering from TRD. PMID:29087373

Deep brain stimulation for treatment-resistant major depressive disorder: a comparison of two targets and long-term follow-up.

PubMed

Raymaekers, S; Luyten, L; Bervoets, C; Gabriëls, L; Nuttin, B

2017-10-31

We previously found that electrical stimulation in the anterior limb of the internal capsule/bed nucleus of the stria terminalis (IC/BST) alleviates depressive symptoms in severe treatment-resistant obsessive-compulsive disorder (OCD) patients. Here we tested the hypothesis that electrical stimulation in either IC/BST or in the inferior thalamic peduncle (ITP) effectively reduces depressive symptoms in treatment-resistant major depressive disorder (TRD). In a double-blind crossover design, the effects of electrical stimulation at both targets were compared in TRD patients. The 17-item Hamilton Depression Rating scale (HAM-D) was the primary outcome measure. During the first crossover, patients received IC/BST stimulation versus no stimulation in random order (2 × 1 weeks). During the second crossover (3 × 2 months), patients received IC/BST versus ITP versus no stimulation. Patients and evaluators were blinded for stimulation conditions. All patients (n=7) were followed up for at least 3 years (3-8 years) after implantation. Six patients completed the first crossover and five patients completed the second. During the first crossover, mean (s.d.) HAM-D scores were 21.5 (2.7) for no stimulation and 11.5 (8.8) for IC/BST stimulation. During the second crossover, HAM-D scores were 15.4 (7.5) for no stimulation, 7.6 (3.8) for IC/BST stimulation and 11.2 (7.5) for ITP stimulation. The final sample size was too small to statistically analyze this second crossover. At last follow-up, only one patient preferred ITP over IC/BST stimulation. Two patients, with a history of suicide attempts before implantation, committed suicide during the follow-up phases of this study. Our data indicate that, in the long term, both ITP and IC/BST stimulation may alleviate depressive symptoms in patients suffering from TRD.

Skating crossovers on a motorized flywheel: a preliminary experimental design to test effect on speed and on crossovers.

PubMed

Smith, Aynsley M; Krause, David A; Stuart, Michael J; Montelpare, William J; Sorenson, Matthew C; Link, Andrew A; Gaz, Daniel V; Twardowski, Casey P; Larson, Dirk R; Stuart, Michael B

2013-12-01

Ice hockey requires frequent skater crossovers to execute turns. Our investigation aimed to determine the effectiveness of training crossovers on a motorized, polyethylene high-resistance flywheel. We hypothesized that high school hockey players training on the flywheel would perform as well as their peers training on ice. Participants were 23 male high-school hockey players (age 15-19 years). The study used an experimental prospective design to compare players who trained for 9 sessions on the 22-foot flywheel with players who trained for 9 sessions on a similarly sized on-ice circle. Both groups were compared with control subjects who were randomly selected from the same participant pool as those training on ice. All players were tested before and after their 3-week training regimens, and control subjects were asked to not practice crossovers between testing. Group 1 trained in a hockey training facility housing the flywheel, and group 2 trained in the ice hockey arena where testing occurred. Primary outcome measures tested in both directions were: (a) speed (time in seconds) required to skate crossovers for 3 laps of a marked face-off circle, (b) cadence of skating crossovers on the similarly sized circles, and (c) a repeat interval speed test, which measures anaerobic power. No significant changes were found between groups in on-ice testing before and after training. Among the group 1 players, 7 of 8 believed they benefited from flywheel training. Group 2 players, who trained on ice, did not improve performance significantly over group 1 players. Despite the fact that no significant on-ice changes in performance were observed in objective measures, players who trained on the flywheel subjectively reported that the flywheel is an effective cost-effective alternative to training on ice. This is a relevant finding when placed in context with limited availability of on-ice training.

Ruxolitinib reduces JAK2 p.V617F allele burden in patients with polycythemia vera enrolled in the RESPONSE study.

PubMed

Vannucchi, Alessandro Maria; Verstovsek, Srdan; Guglielmelli, Paola; Griesshammer, Martin; Burn, Timothy C; Naim, Ahmad; Paranagama, Dilan; Marker, Mahtab; Gadbaw, Brian; Kiladjian, Jean-Jacques

2017-07-01

In patients with polycythemia vera (PV), an elevated JAK2 p.V617F allele burden is associated with indicators of more severe disease (e.g., leukocytosis, splenomegaly, and increased thrombosis risk); however, correlations between allele burden reductions and clinical benefit in patients with PV have not been extensively evaluated in a randomized trial. This exploratory analysis from the multicenter, open-label, phase 3 Randomized Study of Efficacy and Safety in Polycythemia Vera With JAK Inhibitor INCB018424 Versus Best Supportive Care trial evaluated the long-term effect of ruxolitinib treatment on JAK2 p.V617F allele burden in patients with PV. Evaluable JAK2 p.V617F-positive patients randomized to ruxolitinib (n = 107) or best available therapy (BAT) who crossed over to ruxolitinib at week 32 (n = 97) had consistent JAK2 p.V617F allele burden reductions throughout the study. At all time points measured (up to weeks 208 [ruxolitinib-randomized] and 176 [ruxolitinib crossover]), mean changes from baseline over time in JAK2 p.V617F allele burden ranged from -12.2 to -40.0% (ruxolitinib-randomized) and -6.3 to -17.8% (ruxolitinib crossover). Complete or partial molecular response was observed in 3 patients (ruxolitinib-randomized, n = 2; ruxolitinib crossover, n = 1) and 54 patients (ruxolitinib-randomized, n = 33; ruxolitinib crossover, n = 20; BAT, n = 1), respectively. Among patients treated with interferon as BAT (n = 13), the mean maximal reduction in allele burden from baseline was 25.6% after crossover to ruxolitinib versus 6.6% before crossover. Collectively, the data from this exploratory analysis suggest that ruxolitinib treatment for up to 4 years provides progressive reductions in JAK2 p.V617F allele burden in patients with PV who are resistant to or intolerant of hydroxyurea. The relationship between allele burden changes and clinical outcomes in patients with PV remains unclear.

Improved Cathode Structure for a Direct Methanol Fuel Cell

NASA Technical Reports Server (NTRS)

Valdez, Thomas; Narayanan, Sekharipuram

2005-01-01

An improved cathode structure on a membrane/electrode assembly has been developed for a direct methanol fuel cell, in a continuing effort to realize practical power systems containing such fuel cells. This cathode structure is intended particularly to afford better cell performance at a low airflow rate. A membrane/electrode assembly of the type for which the improved cathode structure was developed (see Figure 1) is fabricated in a process that includes brush painting and spray coating of catalyst layers onto a polymer-electrolyte membrane and onto gas-diffusion backings that also act as current collectors. The aforementioned layers are then dried and hot-pressed together. When completed, the membrane/electrode assembly contains (1) an anode containing a fine metal black of Pt/Ru alloy, (2) a membrane made of Nafion 117 or equivalent (a perfluorosulfonic acid-based hydrophilic, proton-conducting ion-exchange polymer), (3) a cathode structure (in the present case, the improved cathode structure described below), and (4) the electrically conductive gas-diffusion backing layers, which are made of Toray 060(TradeMark)(or equivalent) carbon paper containing between 5 and 6 weight percent of poly(tetrafluoroethylene). The need for an improved cathode structure arises for the following reasons: In the design and operation of a fuel-cell power system, the airflow rate is a critical parameter that determines the overall efficiency, cell voltage, and power density. It is desirable to operate at a low airflow rate in order to obtain thermal and water balance and to minimize the size and mass of the system. The performances of membrane/electrode assemblies of prior design are limited at low airflow rates. Methanol crossover increases the required airflow rate. Hence, one way to reduce the required airflow rate is to reduce the effect of methanol crossover. Improvement of the cathode structure - in particular, addition of hydrophobic particles to the cathode - has been demonstrated to mitigate the effects of crossover and decrease the airflow required.

The joy of six: how to control your crossovers.

PubMed

Globus, Samuel T; Keeney, Scott

2012-03-30

Meiotic cells tightly regulate the number and distribution of crossovers to promote accurate chromosome segregation. Yokoo and colleagues uncover a metazoan-specific, cyclin-like protein that is crucial for crossover formation. They utilize this protein's unique properties to explore a remarkable example of biological numerology, whereby nearly every meiotic cell in C. elegans makes precisely six crossovers, one for each of its six chromosome pairs. Copyright © 2012 Elsevier Inc. All rights reserved.

An improved genetic algorithm and its application in the TSP problem

NASA Astrophysics Data System (ADS)

Li, Zheng; Qin, Jinlei

2011-12-01

Concept and research actuality of genetic algorithm are introduced in detail in the paper. Under this condition, the simple genetic algorithm and an improved algorithm are described and applied in an example of TSP problem, where the advantage of genetic algorithm is adequately shown in solving the NP-hard problem. In addition, based on partial matching crossover operator, the crossover operator method is improved into extended crossover operator in order to advance the efficiency when solving the TSP. In the extended crossover method, crossover operator can be performed between random positions of two random individuals, which will not be restricted by the position of chromosome. Finally, the nine-city TSP is solved using the improved genetic algorithm with extended crossover method, the efficiency of whose solution process is much higher, besides, the solving speed of the optimal solution is much faster.

Reversal of apixaban anticoagulation by four-factor prothrombin complex concentrates in healthy subjects: a randomized three-period crossover study.

PubMed

Song, Y; Wang, Z; Perlstein, I; Wang, J; LaCreta, F; Frost, R J A; Frost, C

2017-11-01

Essentials Prothrombin complex concentrates (PCCs) may reverse the effect of factor Xa (FXa) inhibitors. We conducted an open-label, randomized, placebo-controlled, three-period crossover study in 15 subjects. Both PCCs rapidly reversed apixaban-mediated decreases in mean endogenous thrombin potential. Four-factor PCC administration had no effect on apixaban pharmacokinetics or anti-FXa activity. Background Currently, there is no approved reversal agent for direct activated factor Xa (FXa) inhibitors; however, several agents are under investigation, including prothrombin complex concentrates (PCCs). Objective This open-label, randomized, placebo-controlled, three-period crossover study assessed the effect of two four-factor PCCs on apixaban pharmacodynamics and pharmacokinetics in 15 healthy subjects. Methods Subjects received apixaban 10 mg twice daily for 3 days. On day 4, 3 h after apixaban, subjects received a 30-min infusion of 50 IU kg -1 Cofact, Beriplex P/N (Beriplex), or saline. Change in endogenous thrombin potential (ETP), measured with a thrombin generation assay (TGA), was the primary endpoint. Secondary endpoints included changes in other TGA parameters, prothrombin time (PT), International Normalized Ratio (INR), activated partial thromboplastin time, anti-FXa activity, apixaban pharmacokinetics, and safety. Results Apixaban-related changes in ETP and several other pharmacodynamic measures occurred following apixaban administration. Both PCCs reversed apixaban's effect on ETP; the differences in adjusted mean change from pre-PCC baseline to end of infusion were 425 nm min (95% confidence interval [CI] 219.8-630.7 nm min; P < 0.001) for Cofact, and 91 nm min (95% CI - 31.3 to 212.4 nm min; P > 0.05) for Beriplex. Both PCCs returned ETP to pre-apixaban baseline levels 4 h after PCC infusion, versus 45 h for placebo. For both PCCs, mean ETP peaked 21 h after PCC initiation, and then slowly decreased over the following 48 h. Both PCCs reversed apixaban's effect on TGA peak height, PT, and INR. Apixaban pharmacokinetic and anti-FXa profiles were consistent across treatments. Conclusions Cofact and Beriplex reversed apixaban's steady-state effects on several coagulation assessments. © 2017 International Society on Thrombosis and Haemostasis.

A registry-based randomized trial comparing radial and femoral approaches in women undergoing percutaneous coronary intervention: the SAFE-PCI for Women (Study of Access Site for Enhancement of PCI for Women) trial.

PubMed

Rao, Sunil V; Hess, Connie N; Barham, Britt; Aberle, Laura H; Anstrom, Kevin J; Patel, Tejan B; Jorgensen, Jesse P; Mazzaferri, Ernest L; Jolly, Sanjit S; Jacobs, Alice; Newby, L Kristin; Gibson, C Michael; Kong, David F; Mehran, Roxana; Waksman, Ron; Gilchrist, Ian C; McCourt, Brian J; Messenger, John C; Peterson, Eric D; Harrington, Robert A; Krucoff, Mitchell W

2014-08-01

This study sought to determine the effect of radial access on outcomes in women undergoing percutaneous coronary intervention (PCI) using a registry-based randomized trial. Women are at increased risk of bleeding and vascular complications after PCI. The role of radial access in women is unclear. Women undergoing cardiac catheterization or PCI were randomized to radial or femoral arterial access. Data from the CathPCI Registry and trial-specific data were merged into a final study database. The primary efficacy endpoint was Bleeding Academic Research Consortium type 2, 3, or 5 bleeding or vascular complications requiring intervention. The primary feasibility endpoint was access site crossover. The primary analysis cohort was the subgroup undergoing PCI; sensitivity analyses were conducted in the total randomized population. The trial was stopped early for a lower than expected event rate. A total of 1,787 women (691 undergoing PCI) were randomized at 60 sites. There was no significant difference in the primary efficacy endpoint between radial or femoral access among women undergoing PCI (radial 1.2% vs. 2.9% femoral, odds ratio [OR]: 0.39; 95% confidence interval [CI]: 0.12 to 1.27); among women undergoing cardiac catheterization or PCI, radial access significantly reduced bleeding and vascular complications (0.6% vs. 1.7%; OR: 0.32; 95% CI: 0.12 to 0.90). Access site crossover was significantly higher among women assigned to radial access (PCI cohort: 6.1% vs. 1.7%; OR: 3.65; 95% CI: 1.45 to 9.17); total randomized cohort: (6.7% vs. 1.9%; OR: 3.70; 95% CI: 2.14 to 6.40). More women preferred radial access. In this pragmatic trial, which was terminated early, the radial approach did not significantly reduce bleeding or vascular complications in women undergoing PCI. Access site crossover occurred more often in women assigned to radial access. (SAFE-PCI for Women; NCT01406236). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Observing large-scale temporal variability of ocean currents by satellite altimetry - With application to the Antarctic circumpolar current

NASA Technical Reports Server (NTRS)

Fu, L.-L.; Chelton, D. B.

1985-01-01

A new method is developed for studying large-scale temporal variability of ocean currents from satellite altimetric sea level measurements at intersections (crossovers) of ascending and descending orbit ground tracks. Using this method, sea level time series can be constructed from crossover sea level differences in small sample areas where altimetric crossovers are clustered. The method is applied to Seasat altimeter data to study the temporal evolution of the Antarctic Circumpolar Current (ACC) over the 3-month Seasat mission (July-October 1978). The results reveal a generally eastward acceleration of the ACC around the Southern Ocean with meridional disturbances which appear to be associated with bottom topographic features. This is the first direct observational evidence for large-scale coherence in the temporal variability of the ACC. It demonstrates the great potential of satellite altimetry for synoptic observation of temporal variability of the world ocean circulation.

A novel mechanism important for the alignment of microtubules.

PubMed

Wightman, Raymond; Turner, Simon R

2008-04-01

Using a live-cell imaging approach to study individual micro-tubules, we have compared microtubule behavior between net-like and aligned cortical arrays. In contrast to previous studies, a steep angled collision between the growing end of a microtubule and a preexisting microtubule was found to favor crossover. Frequencies of microtubule crossovers, bundling and catastrophes are similar regardless of whether the cell exhibited a net-like or aligned microtubule array. In the predominantly aligned array of petiole cells, severing occurs at the sites of microtubule crossovers and serves to remove unaligned microtubules and to increase microtubule density. Severing was observed to be rare in net-like arrays. Microtubule severing is carried out by the katanin enzyme. In this addendum, we present new insights into the possible mechanism of crossing over and preliminary data looking at organization of the array in a katanin mutant.

Induced interaction in a Fermi gas with a BEC-BCS crossover

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

Yu Zengqiang; Huang Kun; Yin Lan

2009-05-15

We study the effect of the induced interaction on the superfluid transition temperature of a Fermi gas with a Bose-Einstein condensation-Bardeen-Cooper-Schrieffer (BEC-BCS) crossover. The Gorkov-Melik-Barkhudarov theory about the induced interaction is extended from the BCS side to the entire crossover and the pairing fluctuation is treated in the approach by Nozieres and Schmitt-Rink. At unitarity, the induced interaction reduces the transition temperature by about 20%. In the BCS limit, the transition temperature is reduced by a factor of about 2.22, as found by Gorkov and Melik-Barkhudarov. Our result shows that the effect of the induced interaction is important both onmore » the BCS side and in the unitary region.« less

Scan-rate and vacuum pressure dependence of the nucleation and growth dynamics in a spin-crossover single crystal: the role of latent heat.

PubMed

Ridier, Karl; Rat, Sylvain; Salmon, Lionel; Nicolazzi, William; Molnár, Gábor; Bousseksou, Azzedine

2018-04-04

Using optical microscopy we studied the vacuum pressure dependence (0.1-1000 mbar) of the nucleation and growth dynamics of the thermally induced first-order spin transition in a single crystal of the spin-crossover compound [Fe(HB(tz)3)2] (tz = 1,2,4-triazol-1-yl). A crossover between a quasi-static hysteresis regime and a temperature-scan-rate-dependent kinetic regime is evidenced around 5 mbar due to the change of the heat exchange coupling between the crystal and its external environment. Remarkably, the absorption/dissipation rate of latent heat was identified as the key factor limiting the switching speed of the crystal.

Cross-over endocytosis of claudins is mediated by interactions via their extracellular loops.

PubMed

Gehne, Nora; Lamik, Agathe; Lehmann, Martin; Haseloff, Reiner F; Andjelkovic, Anuska V; Blasig, Ingolf E

2017-01-01

Claudins (Cldns) are transmembrane tight junction (TJ) proteins that paracellularly seal endo- and epithelial barriers by their interactions within the TJs. However, the mechanisms allowing TJ remodeling while maintaining barrier integrity are largely unknown. Cldns and occludin are heterophilically and homophilically cross-over endocytosed into neighboring cells in large, double membrane vesicles. Super-resolution microscopy confirmed the presence of Cldns in these vesicles and revealed a distinct separation of Cldns derived from opposing cells within cross-over endocytosed vesicles. Colocalization of cross-over endocytosed Cldn with the autophagosome markers as well as inhibition of autophagosome biogenesis verified involvement of the autophagosomal pathway. Accordingly, cross-over endocytosed Cldns underwent lysosomal degradation as indicated by lysosome markers. Cross-over endocytosis of Cldn5 depended on clathrin and caveolin pathways but not on dynamin. Cross-over endocytosis also depended on Cldn-Cldn-interactions. Amino acid substitutions in the second extracellular loop of Cldn5 (F147A, Q156E) caused impaired cis- and trans-interaction, as well as diminished cross-over endocytosis. Moreover, F147A exhibited an increased mobility in the membrane, while Q156E was not as mobile but enhanced the paracellular permeability. In conclusion, the endocytosis of TJ proteins depends on their ability to interact strongly with each other in cis and trans, and the mobility of Cldns in the membrane is not necessarily an indicator of barrier permeability. TJ-remodeling via cross-over endocytosis represents a general mechanism for the degradation of transmembrane proteins in cell-cell contacts and directly links junctional membrane turnover to autophagy.

X-Chromosome Control of Genome-Scale Recombination Rates in House Mice.

PubMed

Dumont, Beth L

2017-04-01

Sex differences in recombination are widespread in mammals, but the causes of this pattern are poorly understood. Previously, males from two interfertile subspecies of house mice, Mus musculus musculus and M. m. castaneus , were shown to exhibit a ∼30% difference in their global crossover frequencies. Much of this crossover rate divergence is explained by six autosomal loci and a large-effect locus on the X chromosome. Intriguingly, the allelic effects at this X-linked locus are transgressive, with the allele conferring increased crossover rate being transmitted by the low crossover rate M. m. castaneus parent. Despite the pronounced divergence between males, females from these subspecies exhibit similar crossover rates, raising the question of how recombination is genetically controlled in this sex. Here, I analyze publicly available genotype data from early generations of the Collaborative Cross, an eight-way panel of recombinant inbred strains, to estimate crossover frequencies in female mice with sex-chromosome genotypes of diverse subspecific origins. Consistent with the transgressive influence of the X chromosome in males, I show that females inheriting an M. m. castaneus X possess higher average crossover rates than females lacking the M. m. castaneus X chromosome. The differential inheritance of the X chromosome in males and females provides a simple genetic explanation for sex-limited evolution of this trait. Further, the presence of X-linked and autosomal crossover rate modifiers with antagonistic effects hints at an underlying genetic conflict fueled by selection for distinct crossover rate optima in males and females. Copyright © 2017 by the Genetics Society of America.

Zinc chloride modified electronic transport and relaxation studies in barium-tellurite glasses

NASA Astrophysics Data System (ADS)

Dhankhar, Sunil; Kundu, R. S.; Rani, Sunita; Sharma, Preeti; Murugavel, S.; Punia, Rajesh; Kishore, N.

2017-09-01

The ac conductivity of halide based tellurium glasses having composition 70 TeO2-(30-x) BaO-x ZnCl2; x = 5, 10, 15, 20 and 25 has been investigated in the frequency range 10-1 Hz to 105Hz and in the temperature range 453 K to 553 K. The frequency and temperature dependent ac conductivity show mixed behaviour with increase in halide content and found to obey Jonscher's universal power law. The values of dc conductivity, crossover frequency and frequency exponent have been estimated from the fitting of experimental data of ac conductivity with Jonscher's universal power law. For determining the conduction mechanism in studied glass system, frequency exponent has been analyzed by various theoretical models. In presently studied glasses, the ac conduction takes place via overlapping large polaron tunneling (OLPT). The values of activation energy for dc conduction (W) and the one associated with relaxation process ( E R) are found to increase with increase in x up to glass sample with x = 15 and thereafter it decrease with increase in zinc chloride content. DC conduction takes place via variable range hopping (VRH) as proposed by Mott with some modification suggested by Punia et al. The value of real part of modulus ( M') is observed to decrease with increase in temperature. The value of stretched exponent (β) obtained from fitting of M'' reveals the presence of non-Debye type of relaxation in presently studied glass samples. Scaling spectra of ac conductivity and values of electric modulus ( M' and M'') collapse into a single master curve for all the compositions and temperatures. The values of relaxation energy ( E R) for all the studied glass compositions are almost equal to W, suggesting that polarons have to overcome same barrier while relaxing and conducting. The conduction and relaxation processes in the studied glass samples are composition and temperature independent. [Figure not available: see fulltext.

Higher-than-ballistic conduction of viscous electron flows

PubMed Central

Guo, Haoyu; Ilseven, Ekin; Falkovich, Gregory; Levitov, Leonid S.

2017-01-01

Strongly interacting electrons can move in a neatly coordinated way, reminiscent of the movement of viscous fluids. Here, we show that in viscous flows, interactions facilitate transport, allowing conductance to exceed the fundamental Landauer’s ballistic limit Gball. The effect is particularly striking for the flow through a viscous point contact, a constriction exhibiting the quantum mechanical ballistic transport at T=0 but governed by electron hydrodynamics at elevated temperatures. We develop a theory of the ballistic-to-viscous crossover using an approach based on quasi-hydrodynamic variables. Conductance is found to obey an additive relation G=Gball+Gvis, where the viscous contribution Gvis dominates over Gball in the hydrodynamic limit. The superballistic, low-dissipation transport is a generic feature of viscous electronics. PMID:28265079

Pairwise Maximum Entropy Models for Studying Large Biological Systems: When They Can Work and When They Can't

PubMed Central

Roudi, Yasser; Nirenberg, Sheila; Latham, Peter E.

2009-01-01

One of the most critical problems we face in the study of biological systems is building accurate statistical descriptions of them. This problem has been particularly challenging because biological systems typically contain large numbers of interacting elements, which precludes the use of standard brute force approaches. Recently, though, several groups have reported that there may be an alternate strategy. The reports show that reliable statistical models can be built without knowledge of all the interactions in a system; instead, pairwise interactions can suffice. These findings, however, are based on the analysis of small subsystems. Here, we ask whether the observations will generalize to systems of realistic size, that is, whether pairwise models will provide reliable descriptions of true biological systems. Our results show that, in most cases, they will not. The reason is that there is a crossover in the predictive power of pairwise models: If the size of the subsystem is below the crossover point, then the results have no predictive power for large systems. If the size is above the crossover point, then the results may have predictive power. This work thus provides a general framework for determining the extent to which pairwise models can be used to predict the behavior of large biological systems. Applied to neural data, the size of most systems studied so far is below the crossover point. PMID:19424487

Superconducting dome in doped quasi-two-dimensional organic Mott insulators: A paradigm for strongly correlated superconductivity

NASA Astrophysics Data System (ADS)

Hébert, Charles-David; Sémon, Patrick; Tremblay, A.-M. S.

2015-11-01

Layered organic superconductors of the BEDT family are model systems for understanding the interplay of the Mott transition with superconductivity, magnetic order, and frustration, ingredients that are essential to understand superconductivity also in the cuprate high-temperature superconductors. Recent experimental studies on a hole-doped version of the organic compounds reveals an enhancement of superconductivity and a rapid crossover between two different conducting phases above the superconducting dome. One of these phases is a Fermi liquid, the other not. Using plaquette cellular dynamical mean field theory with state-of-the-art continuous-time quantum Monte Carlo calculations, we study this problem with the two-dimensional Hubbard model on the anisotropic triangular lattice. Phase diagrams as a function of temperature T and interaction strength U /t are obtained for anisotropy parameters t'=0.4 t ,t'=0.8 t and for various fillings. As in the case of the cuprates, we find, at finite doping, a first-order transition between two normal-state phases. One of theses phases has a pseudogap while the other does not. At temperatures above the critical point of the first-order transition, there is a Widom line where crossovers occur. The maximum (optimal) superconducting critical temperature Tcm at finite doping is enhanced by about 25% compared with its maximum at half filling and the range of U /t where superconductivity appears is greatly extended. These results are in broad agreement with experiment. Also, increasing frustration (larger t'/t ) significantly reduces magnetic ordering, as expected. This suggests that for compounds with intermediate to high frustration, very light doping should reveal the influence of the first-order transition and associated crossovers. These crossovers could possibly be even visible in the superconducting phase through subtle signatures. We also predict that destroying the superconducting phase by a magnetic field should reveal the first-order transition between metal and pseudogap. Finally, we predict that electron doping should also lead to an increased range of U /t for superconductivity but with a reduced maximum Tc. This work also clearly shows that the superconducting dome in organic superconductors is tied to the Mott transition and its continuation as a transition separating pseudogap phase from correlated metal in doped compounds, as in the cuprates. Contrary to heavy fermions for example, the maximum Tc is definitely not attached to an antiferromagnetic quantum critical point. That can also be verified experimentally.

Topoisomerase II Mediates Meiotic Crossover Interference

PubMed Central

Zhang, Liangran; Wang, Shunxin; Yin, Shen; Hong, Soogil; Kim, Keun P.; Kleckner, Nancy

2014-01-01

Summary Spatial patterning is a ubiquitous feature of biological systems. Meiotic crossovers provide an interesting example, defined by the classical phenomenon of crossover interference. Here, analysis of crossover patterns in budding yeast identifies a molecular pathway for interference. Topoisomerase II (Topo II) plays a central role, thus identifying a new function for this critical molecule. SUMOylation [of TopoII and axis component Red1] and ubiquitin-mediated removal of SUMOylated proteins are also required. These and other findings support the hypothesis that crossover interference involves accumulation, relief and redistribution of mechanical stress along the protein/DNA meshwork of meiotic chromosome axes, with TopoII required to adjust spatial relationships among DNA segments. PMID:25043020

Interparental Violence and the Mediating Role of Parental Availability in Children's Trauma Related Symptoms.

PubMed

Visser, Margreet; Schoemaker, Kim; de Schipper, Clasien; Lamers-Winkelman, Francien; Finkenauer, Catrin

This cross-sectional study examined the hypothesis that parental psychopathology in Interparental Violence (IPV) families crosses over to children, because parental psychopathology spills over to parental functioning. In a high-risk sample of IPV exposed families, we tested whether parental psychopathology spills over to parental availability, which, in turn, shows a crossover effect to children's trauma-related symptoms. The study population consisted of 78 IPV exposed children (4-12 years), and their 65 custodial parents referred to outpatient Children's Trauma Centers in the Netherlands for intervention. Consistent with our hypotheses, parental psychopathology was negatively related to parental availability, suggesting a spillover effect. Although parental psychopathology was not associated with children's trauma-related symptoms directly, we found evidence for the predicted indirect, crossover effects. We found an indirect crossover effect from parental psychopathology to children's trauma-related anxiety, depression, and anger, through the spillover effect of parental availability. Clinical implications for treatment and study limitations are discussed.

Dual-frequency dielectrophoretic levitation of Canola protoplasts.

PubMed

Kaler, K V; Xie, J P; Jones, T B; Paul, R

1992-07-01

A novel dual-frequency excitation technique is introduced which permits investigation of the low-frequency dispersion of Canola plant protoplasts using feedback-controlled dielectrophoretic levitation. The upper and intermediate frequency spectra obtained using the new technique are generally consistent with previous work. However, below some cross-over frequency f(OL), the protoplasts exhibit an apparent positive dielectrophoretic response that is not predicted by conventional theory. This cross-over frequency is linearly related to suspension conductivity, virtually independent of the suspension pH, and inversely proportional to the square of the cell radius. Examination of the complex Clausius-Mossotti polarization coefficient reveals that the observed positive dielectrophoretic response can not be accounted for in terms of Maxwell-Wagner polarization associated with a conventional layered model for the protoplast. The failure of straightforward enhancements to the protoplast model in explaining the low frequency behavior may indicate the presence of an electrophoretic contribution to the net observable force on the particle. To account for such fluid mechanical effects, it will be necessary to modify the existing dielectrophoretic force formulation.

Electrical conductivity and modulus formulation in zinc modified bismuth boro-tellurite glasses

NASA Astrophysics Data System (ADS)

Dhankhar, Sunil; Kundu, R. S.; Dult, Meenakshi; Murugavel, S.; Punia, R.; Kishore, N.

2016-09-01

The ac conductivity of zinc modified tellurium based quaternary glasses having composition 60 TeO2-10 B2O3-(30 - x) Bi2O3-x ZnO; x = 10, 15, 20, 25 and 30 has been investigated in the frequency range 10-1-105 Hz and in temperature range 483-593 K. Frequency and temperature dependent ac conductivity found to obey Jonscher power law modified by Almond-West. DC conductivity, crossover frequency and frequency exponent have been estimated from the fitting of the experimental data of conductivity with Jonscher power law modified by Almond-West. The ac conductivity and its frequency exponent have been analyzed by various theoretical models. In presently studied glasses ac conduction takes place via tunneling of overlapping large polaron tunneling. Activation energy is found to be increased with increase in zinc content and dc conduction takes place via variable range hopping proposed by Mott with some modification suggested by Punia et al. The value of the stretched exponent ( β) obtained by fitting of M^' ' }} reveals the presence of non-Debye type relaxation. Scaling spectra of ac conductivity and electric modulus collapse into a single master curve for all compositions and temperatures, reveals the presence of composition and temperature independent conduction and relaxation process in these glasses. Activation energy of conduction ( W) and electric modulus ( E R ) are nearly equal, indicating that polaron have to overcome the same energy barrier during conduction as well as relaxation processes.

Computer-Enriched Instruction (CEI) Is Better for Preview Material Instead of Review Material: An Example of a Biostatistics Chapter, the Central Limit Theorem

ERIC Educational Resources Information Center

See, Lai-Chu; Huang, Yu-Hsun; Chang, Yi-Hu; Chiu, Yeo-Ju; Chen, Yi-Fen; Napper, Vicki S.

2010-01-01

This study examines the timing using computer-enriched instruction (CEI), before or after a traditional lecture to determine cross-over effect, period effect, and learning effect arising from sequencing of instruction. A 2 x 2 cross-over design was used with CEI to teach central limit theorem (CLT). Two sequences of graduate students in nursing…

Melatonin versus Placebo in Children with Autism Spectrum Conditions and Severe Sleep Problems Not Amenable to Behaviour Management Strategies: A Randomised Controlled Crossover Trial

ERIC Educational Resources Information Center

Wright, Barry; Sims, David; Smart, Siobhan; Alwazeer, Ahmed; Alderson-Day, Ben; Allgar, Victoria; Whitton, Clare; Tomlinson, Heather; Bennett, Sophie; Jardine, Jenni; McCaffrey, Nicola; Leyland, Charlotte; Jakeman, Christine; Miles, Jeremy

2011-01-01

Twenty-two children with autism spectrum disorders who had not responded to supported behaviour management strategies for severe dysomnias entered a double blind, randomised, controlled crossover trial involving 3 months of placebo versus 3 months of melatonin to a maximum dose of 10 mg. 17 children completed the study. There were no significant…

Universality-class crossover by a nonorder field introduced to the pair contact process with diffusion

NASA Astrophysics Data System (ADS)

Park, Su-Chan

2017-09-01

The one-dimensional pair contact process with diffusion (PCPD), an interacting particle system with diffusion, pair annihilation, and creation by pairs, has defied consensus about the universality class to which it belongs. An argument by Hinrichsen [Physica A 361, 457 (2006), 10.1016/j.physa.2005.06.101] claims that freely diffusing particles in the PCPD should play the same role as frozen particles when it comes to the critical behavior. Therefore, the PCPD is claimed to have the same critical phenomena as a model with infinitely many absorbing states that belongs to the directed percolation (DP) universality class. To investigate if diffusing particles are really indistinguishable from frozen particles in the sense of the renormalization group, we study numerically a variation of the PCPD by introducing a nonorder field associated with infinitely many absorbing states. We find that a crossover from the PCPD to DP occurs due to the nonorder field. By studying a similar model, we exclude the possibility that the mere introduction of a nonorder field to one model can entail a nontrivial crossover to another model in the same universality class, thus we attribute the observed crossover to the difference of the universality class of the PCPD from the DP class.

Role of confinements on the melting of Wigner molecules in quantum dots

NASA Astrophysics Data System (ADS)

Bhattacharya, Dyuti; Filinov, Alexei V.; Ghosal, Amit; Bonitz, Michael

2016-03-01

We explore the stability of a Wigner molecule (WM) formed in confinements with different geometries emulating the role of disorder and analyze the melting (or crossover) of such a system. Building on a recent calculation [D. Bhattacharya, A. Ghosal, Eur. Phys. J. B 86, 499 (2013)] that discussed the effects of irregularities on the thermal crossover in classical systems, we expand our studies in the untested territory by including both the effects of quantum fluctuations and of disorder. Our results, using classical and quantum (path integral) Monte Carlo techniques, unfold complementary mechanisms that drive the quantum and thermal crossovers in a WM and show that the symmetry of the confinement plays no significant role in determining the quantum crossover scale n X . This is because the zero-point motion screens the boundary effects within short distances. The phase diagram as a function of thermal and quantum fluctuations determined from independent criteria is unique, and shows "melting" from the WM to both the classical and quantum "liquids". An intriguing signature of weakening liquidity with increasing temperature, T, is found in the extreme quantum regime. The crossover is associated with production of defects. However, these defects appear to play distinct roles in driving the quantum and thermal "melting". Our analyses carry serious implications for a variety of experiments on many-particle systems - semiconductor heterostructure quantum dots, trapped ions, nanoclusters, colloids and complex plasma.

Crossover and maximal fat-oxidation points in sedentary healthy subjects: methodological issues.

PubMed

Gmada, N; Marzouki, H; Haboubi, M; Tabka, Z; Shephard, R J; Bouhlel, E

2012-02-01

Our study aimed to assess the influence of protocol on the crossover point and maximal fat-oxidation (LIPOX(max)) values in sedentary, but otherwise healthy, young men. Maximal oxygen intake was assessed in 23 subjects, using a progressive maximal cycle ergometer test. Twelve sedentary males (aged 20.5±1.0 years) whose directly measured maximal aerobic power (MAP) values were lower than their theoretical maximal values (tMAP) were selected from this group. These individuals performed, in random sequence, three submaximal graded exercise tests, separated by three-day intervals; work rates were based on the tMAP in one test and on MAP in the remaining two. The third test was used to assess the reliability of data. Heart rate, respiratory parameters, blood lactate, the crossover point and LIPOX(max) values were measured during each of these tests. The crossover point and LIPOX(max) values were significantly lower when the testing protocol was based on tMAP rather than on MAP (P<0.001). Respiratory exchange ratios were significantly lower with MAP than with tMAP at 30, 40, 50 and 60% of maximal aerobic power (P<0.01). At the crossover point, lactate and 5-min postexercise oxygen consumption (EPOC(5 min)) values were significantly higher using tMAP rather than MAP (P<0.001). During the first 5 min of recovery, EPOC(5 min) and blood lactate were significantly correlated (r=0.89; P<0.001). Our data show that, to assess the crossover point and LIPOX(max) values for research purposes, the protocol must be based on the measured MAP rather than on a theoretical value. Such a determination should improve individualization of training for initially sedentary subjects. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Associations of daily pediatric asthma emergency department visits with air pollution in Newark, NJ: utilizing time-series and case-crossover study designs.

PubMed

Gleason, Jessie A; Fagliano, Jerald A

2015-10-01

Asthma is one of the most common chronic diseases affecting children. This study assesses the associations of ozone and fine particulate matter (PM2.5) with pediatric emergency department visits in the urban environment of Newark, NJ. Two study designs were utilized and evaluated for usability. We obtained daily emergency department visits among children aged 3-17 years with a primary diagnosis of asthma during April to September for 2004-2007. Both a time-stratified case-crossover study design with bi-directional control sampling and a time-series study design were utilized. Lagged effects (1-d through 5-d lag, 3-d average, and 5-d average) of ozone and PM2.5 were explored and a dose-response analysis comparing the bottom 5th percentile of 3-d average lag ozone with each 5 percentile increase was performed. Associations of interquartile range increase in same-day ozone were similar between the time-series and case-crossover study designs (RR = 1.08, 95% CI 1.04-1.12) and (OR = 1.10, 95% CI 1.06-1.14), respectively. Similar associations were seen for 1-day lag and 3-day average lag ozone levels. PM2.5 was not associated with the outcome in either study design. Dose-response assessment indicated a statistically significant and increasing association around 50-55 ppb consistent for both study designs. Ozone was statistically positively associated with pediatric asthma ED visits in Newark, NJ. Our results were generally comparable across the time-series and case-crossover study designs, indicating both are useful to assess local air pollution impacts.

Using a single tablet daily to treat latent tuberculosis infection in Brazil: bioequivalence of two different isoniazid formulations (300 mg and 100 mg) demonstrated by a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry method in a randomised, crossover study.

PubMed

Daher, André; Pitta, Luciana; Santos, Tereza; Barreira, Draurio; Pinto, Douglas

2015-06-01

The recommended treatment for latent tuberculosis (TB) infection in adults is a daily dose of isoniazid (INH) 300 mg for six months. In Brazil, INH was formulated as 100 mg tablets. The treatment duration and the high pill burden compromised patient adherence to the treatment. The Brazilian National Programme for Tuberculosis requested a new 300 mg INH formulation. The aim of our study was to compare the bioavailability of the new INH 300 mg formulation and three 100 mg tablets of the reference formulation. We conducted a randomised, single dose, open label, two-phase crossover bioequivalence study in 28 healthy human volunteers. The 90% confidence interval for the INH maximum concentration of drug observed in plasma and area under the plasma concentration vs. time curve from time zero to the last measurable concentration "time t" was 89.61-115.92 and 94.82-119.44, respectively. The main limitation of our study was that neither adherence nor the safety profile of multiple doses was evaluated. To determine the level of INH in human plasma, we developed and validated a sensitive, simple and rapid high-performance liquid chromatography-tandem mass spectrometry method. Our results showed that the new formulation was bioequivalent to the 100 mg reference product. This finding supports the use of a single 300 mg tablet daily strategy to treat latent TB. This new formulation may increase patients' adherence to the treatment and quality of life.

Geosat crossover analysis in the tropical Pacific. Part 1: Constrained sinusoidal crossover adjustment

NASA Technical Reports Server (NTRS)

Tai, Chang-Kou

1988-01-01

A new method (constrained sinusoidal crossover adjustment) for removing the orbit error in satellite altimetry is tested (using crossovers accumulated in the first 91 days of the Geosat non-repeat era in the tropical Pacific) and found to have excellent qualities. Two features distinguish the new method from the conventional bias-and-tilt crossover adjustment. First, a sine wave (with wavelength equaling the circumference of the Earth) is used to represent the orbit error for each satellite revolution, instead of the bias-and-tilt (and curvature, if necessary) approach for each segment of the satellite ground track. Secondly, the indeterminacy of the adjustment process is removed by a simple constraint minimizing the amplitudes of the sine waves, rather than by fixing selected tracks. Overall the new method is more accurate, more efficient, and much less cumbersome than the old. The idea of restricting the crossover adjustment to crossovers between tracks that are less than certain days apart in order to preserve the large-scale long-term oceanic variability is also tested with inconclusive results because the orbit error was unusually nonstationary in the initial 91 days of the GEOSAT mission.

Local chromosome context is a major determinant of crossover pathway biochemistry during budding yeast meiosis

PubMed Central

Medhi, Darpan; Goldman, Alastair SH; Lichten, Michael

2016-01-01

The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions. DOI: http://dx.doi.org/10.7554/eLife.19669.001 PMID:27855779

The exposure-crossover design is a new method for studying sustained changes in recurrent events.

PubMed

Redelmeier, Donald A

2013-09-01

To introduce a new design that explores how an acute exposure might lead to a sustained change in the risk of a recurrent outcome. The exposure-crossover design uses self-matching to control within-person confounding due to genetics, personality, and all other stable patient characteristics. The design is demonstrated using population-based individual-level health data from Ontario, Canada, for three separate medical conditions (n > 100,000 for each) related to the risk of a motor vehicle crash (total outcomes, >2,000 for each). The exposure-crossover design yields numerical risk estimates during the baseline interval before an intervention, the induction interval immediately ahead of the intervention, and the subsequent interval after the intervention. Accompanying graphs summarize results, provide an intuitive display to readers, and show risk comparisons (absolute and relative). Self-matching increases statistical efficiency, reduces selection bias, and yields quantitative analyses. The design has potential limitations related to confounding, artifacts, pragmatics, survivor bias, statistical models, potential misunderstandings, and serendipity. The exposure-crossover design may help in exploring selected questions in epidemiology science. Copyright © 2013 Elsevier Inc. All rights reserved.

Superfluid density of states and pseudogap phenomenon in the BCS-BEC crossover regime of a superfluid Fermi gas

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

Watanabe, Ryota; Tsuchiya, Shunji; CREST

2010-10-15

We investigate single-particle excitations and strong-coupling effects in the BCS-BEC crossover regime of a superfluid Fermi gas. Including phase and amplitude fluctuations of the superfluid order parameter within a T-matrix theory, we calculate the superfluid density of states (DOS), as well as single-particle spectral weight, over the entire BCS-BEC crossover region below the superfluid transition temperature T{sub c}. We clarify how the pseudogap in the normal state evolves into the superfluid gap, as one passes through T{sub c}. While the pseudogap in DOS continuously evolves into the superfluid gap in the weak-coupling BCS regime, the superfluid gap in the crossovermore » region is shown to appear in DOS after the pseudogap disappears below T{sub c}. In the phase diagram with respect to the temperature and interaction strength, we determine the region where strong pairing fluctuations dominate over single-particle properties of the system. Our results would be useful for the study of strong-coupling phenomena in the BCS-BEC crossover regime of a superfluid Fermi gas.« less

Single-crossover recombination in discrete time.

PubMed

von Wangenheim, Ute; Baake, Ellen; Baake, Michael

2010-05-01

Modelling the process of recombination leads to a large coupled nonlinear dynamical system. Here, we consider a particular case of recombination in discrete time, allowing only for single crossovers. While the analogous dynamics in continuous time admits a closed solution (Baake and Baake in Can J Math 55:3-41, 2003), this no longer works for discrete time. A more general model (i.e. without the restriction to single crossovers) has been studied before (Bennett in Ann Hum Genet 18:311-317, 1954; Dawson in Theor Popul Biol 58:1-20, 2000; Linear Algebra Appl 348:115-137, 2002) and was solved algorithmically by means of Haldane linearisation. Using the special formalism introduced by Baake and Baake (Can J Math 55:3-41, 2003), we obtain further insight into the single-crossover dynamics and the particular difficulties that arise in discrete time. We then transform the equations to a solvable system in a two-step procedure: linearisation followed by diagonalisation. Still, the coefficients of the second step must be determined in a recursive manner, but once this is done for a given system, they allow for an explicit solution valid for all times.

Meiotic recombination hotspots - a comparative view.

PubMed

Choi, Kyuha; Henderson, Ian R

2015-07-01

During meiosis homologous chromosomes pair and undergo reciprocal genetic exchange, termed crossover. Meiotic recombination has a profound effect on patterns of genetic variation and is an important tool during crop breeding. Crossovers initiate from programmed DNA double-stranded breaks that are processed to form single-stranded DNA, which can invade a homologous chromosome. Strand invasion events mature into double Holliday junctions that can be resolved as crossovers. Extensive variation in the frequency of meiotic recombination occurs along chromosomes and is typically focused in narrow hotspots, observed both at the level of DNA breaks and final crossovers. We review methodologies to profile hotspots at different steps of the meiotic recombination pathway that have been used in different eukaryote species. We then discuss what these studies have revealed concerning specification of hotspot locations and activity and the contributions of both genetic and epigenetic factors. Understanding hotspots is important for interpreting patterns of genetic variation in populations and how eukaryotic genomes evolve. In addition, manipulation of hotspots will allow us to accelerate crop breeding, where meiotic recombination distributions can be limiting. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

49 CFR 236.203 - Hand operated crossover between main tracks; protection.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Electric locking of the switches of the crossover. Signals governing movements over either switch shall... crossover is occupied by a train, locomotive or car in such a manner as to foul the main track. It shall not... electric locking releases. ...

49 CFR 236.203 - Hand operated crossover between main tracks; protection.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Electric locking of the switches of the crossover. Signals governing movements over either switch shall... crossover is occupied by a train, locomotive or car in such a manner as to foul the main track. It shall not... electric locking releases. ...

49 CFR 236.203 - Hand operated crossover between main tracks; protection.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Electric locking of the switches of the crossover. Signals governing movements over either switch shall... crossover is occupied by a train, locomotive or car in such a manner as to foul the main track. It shall not... electric locking releases. ...

24 CFR 3285.701 - Electrical crossovers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section require...

24 CFR 3285.701 - Electrical crossovers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section require...

24 CFR 3285.701 - Electrical crossovers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section require...

24 CFR 3285.701 - Electrical crossovers.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section require...

49 CFR 236.203 - Hand operated crossover between main tracks; protection.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Electric locking of the switches of the crossover. Signals governing movements over either switch shall... crossover is occupied by a train, locomotive or car in such a manner as to foul the main track. It shall not... electric locking releases. ...

49 CFR 236.203 - Hand operated crossover between main tracks; protection.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Electric locking of the switches of the crossover. Signals governing movements over either switch shall... crossover is occupied by a train, locomotive or car in such a manner as to foul the main track. It shall not... electric locking releases. ...

Single-center, single-dose, open-label, randomized, two-period crossover study on the bioavailability of methotrexate administered using a novel prefilled, needle-free delivery system.

PubMed

Bienvenu, Boris; Aouba, Achille; Gottenberg, Jacques-Eric; Verstuyft, Celine

2017-04-01

Zeneo 1 is a needle-free injection device. We performed a pharmacokinetic study to investigate the bioequivalence of methotrexate administered subcutaneously using either the needle-free injection device or a conventional needle and syringe. This was a single-dose, open-label, laboratory-blind, randomized crossover study performed in adult healthy volunteers. Each participant received two methotrexate injections (each 25 mg), one via needle-free injection device and one via conventional injection, with a 21-28 day wash-out interval between dosing. For each participant, the administration site for both injections was either the abdomen or the thigh. The primary pharmacokinetic outcome parameters were AUC (0- t ) and C max . Bioequivalence was assessed by standard criteria: whether 90% confidence intervals of geometric mean ratios for the two administration methods were within 80-125%. Fifty-two individuals completed the study. Bioequivalence criteria were met for AUC (0- t ) , for the overall analysis (both injection sites: 90% confidence interval: 99.4-103.1%), and for each injection site separately. Bioequivalence was similarly demonstrated with AUC (0-∞) . Bioequivalence criteria for C max were fulfilled for abdominal administration but not for the overall analysis. Injection via the needle-free injection device was well tolerated. Limitations include conducting the study in healthy volunteers and the relatively small subject number (albeit satisfactory for bioequivalence). This study shows that methotrexate injection via needle-free injection device is bioequivalent to a conventional needle and syringe in relation to AUC (0- t ) and AUC (0-∞) . Studies of needle-free injection device use in patients requiring methotrexate therapy are planned.

Bio-Inspired Genetic Algorithms with Formalized Crossover Operators for Robotic Applications.

PubMed

Zhang, Jie; Kang, Man; Li, Xiaojuan; Liu, Geng-Yang

2017-01-01

Genetic algorithms are widely adopted to solve optimization problems in robotic applications. In such safety-critical systems, it is vitally important to formally prove the correctness when genetic algorithms are applied. This paper focuses on formal modeling of crossover operations that are one of most important operations in genetic algorithms. Specially, we for the first time formalize crossover operations with higher-order logic based on HOL4 that is easy to be deployed with its user-friendly programing environment. With correctness-guaranteed formalized crossover operations, we can safely apply them in robotic applications. We implement our technique to solve a path planning problem using a genetic algorithm with our formalized crossover operations, and the results show the effectiveness of our technique.

Random-effects linear modeling and sample size tables for two special crossover designs of average bioequivalence studies: the four-period, two-sequence, two-formulation and six-period, three-sequence, three-formulation designs.

PubMed

Diaz, Francisco J; Berg, Michel J; Krebill, Ron; Welty, Timothy; Gidal, Barry E; Alloway, Rita; Privitera, Michael

2013-12-01

Due to concern and debate in the epilepsy medical community and to the current interest of the US Food and Drug Administration (FDA) in revising approaches to the approval of generic drugs, the FDA is currently supporting ongoing bioequivalence studies of antiepileptic drugs, the EQUIGEN studies. During the design of these crossover studies, the researchers could not find commercial or non-commercial statistical software that quickly allowed computation of sample sizes for their designs, particularly software implementing the FDA requirement of using random-effects linear models for the analyses of bioequivalence studies. This article presents tables for sample-size evaluations of average bioequivalence studies based on the two crossover designs used in the EQUIGEN studies: the four-period, two-sequence, two-formulation design, and the six-period, three-sequence, three-formulation design. Sample-size computations assume that random-effects linear models are used in bioequivalence analyses with crossover designs. Random-effects linear models have been traditionally viewed by many pharmacologists and clinical researchers as just mathematical devices to analyze repeated-measures data. In contrast, a modern view of these models attributes an important mathematical role in theoretical formulations in personalized medicine to them, because these models not only have parameters that represent average patients, but also have parameters that represent individual patients. Moreover, the notation and language of random-effects linear models have evolved over the years. Thus, another goal of this article is to provide a presentation of the statistical modeling of data from bioequivalence studies that highlights the modern view of these models, with special emphasis on power analyses and sample-size computations.

Extended precedence preservative crossover for job shop scheduling problems

NASA Astrophysics Data System (ADS)

Ong, Chung Sin; Moin, Noor Hasnah; Omar, Mohd

2013-04-01

Job shop scheduling problems (JSSP) is one of difficult combinatorial scheduling problems. A wide range of genetic algorithms based on the two parents crossover have been applied to solve the problem but multi parents (more than two parents) crossover in solving the JSSP is still lacking. This paper proposes the extended precedence preservative crossover (EPPX) which uses multi parents for recombination in the genetic algorithms. EPPX is a variation of the precedence preservative crossover (PPX) which is one of the crossovers that perform well to find the solutions for the JSSP. EPPX is based on a vector to determine the gene selected in recombination for the next generation. Legalization of children (offspring) can be eliminated due to the JSSP representation encoded by using permutation with repetition that guarantees the feasibility of chromosomes. The simulations are performed on a set of benchmarks from the literatures and the results are compared to ensure the sustainability of multi parents recombination in solving the JSSP.

Genetic Recombination at the Buff Spore Color Locus in SORDARIA BREVICOLLIS. II. Analysis of Flanking Marker Behavior in Crosses between Buff Mutants.

PubMed

Sang, H; Whitehouse, H L

1983-02-01

Aberrant asci containing one or more wild-type spores were selected from crosses between pairs of alleles of the buff locus in the presence of closely linked flanking markers. Data were obtained relating to the site of aberrant segregation and the position of any associated crossover giving recombination of flanking markers. Aberrant segregation at a proximal site within the buff gene may be associated with a crossover proximal to the site of aberrant segregation or, with equal frequency, with a crossover distal to the site of the second mutant present in the cross. Similarly, segregation at a distal site may be associated with a crossover distal to the site or, with lower frequency, with a crossover proximal to the site of the proximal mutant present in the cross. Crossovers between the alleles were rare. This evidence for the relationship between hybrid DNA and crossing over is discussed in terms of current models for the mechanism of recombination.

Weather conditions may worsen symptoms in rheumatoid arthritis patients: the possible effect of temperature.

PubMed

Abasolo, Lydia; Tobías, Aurelio; Leon, Leticia; Carmona, Loreto; Fernandez-Rueda, Jose Luis; Rodriguez, Ana Belen; Fernandez-Gutierrez, Benjamin; Jover, Juan Angel

2013-01-01

Patients with rheumatoid arthritis (RA) complain that weather conditions aggravate their symptoms. We investigated the short-term effects of weather conditions on worsening of RA and determined possible seasonal fluctuations. We conducted a case-crossover study in Madrid, Spain. Daily cases of RA flares were collected from the emergency room of a tertiary level hospital between 2004 and 2007. 245 RA patients who visited the emergency room 306 times due to RA related complaints as the main diagnostic reason were included in the study. Patients from 50 to 65 years old were 16% more likely to present a flare with lower mean temperatures. Our results support the belief that weather influences rheumatic pain in middle aged patients. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Can the Farnsworth D15 Color Vision Test Be Defeated through Practice?

PubMed

Ng, Jason S; Liem, Sophia C

2018-05-01

This study suggests that it is possible for some patients with severe red-green color vision deficiency to do perfectly on the Farnsworth D15 test after practicing it. The Farnsworth D15 is a commonly used test to qualify people for certain occupations. For patients with color vision deficiency, there may be high motivation to try to pass the test through practice to gain entry into a particular occupation. There is no evidence in the literature on whether it is possible for patients to learn to pass the D15 test through practice. Ten subjects with inherited red-green color vision deficiency and 15 color-normal subjects enrolled in the study. All subjects had anomaloscope testing, color vision book tests, and a Farnsworth D15 at an initial visit. For the D15, the number of major crossovers was determined for each subject. Failing the D15 was determined as greater than 1 major crossover. Subjects with color vision deficiency practiced the D15 as long as desired to achieve a perfect score and then returned for a second visit for D15 testing. A paired t test was used to analyze the number of major crossovers at visit 1 versus visit 2. Color-normal subjects did not have any major crossovers. Subjects with color vision deficiency had significantly (P < .001) fewer major crossovers on the D15 test at visit 2 (mean/SD = 2.5/3.0), including five subjects with dichromacy that achieved perfect D15 performance, compared to visit 1 (mean/SD = 8.7/1.3). Practice of the Farnsworth D15 test can lead to perfect performance for some patients with color vision deficiency, and this should be considered in certain cases where occupational entry is dependent on D15 testing.

Dynamic and thermodynamic crossover scenarios in the Kob-Andersen mixture: Insights from multi-CPU and multi-GPU simulations.

PubMed

Coslovich, Daniele; Ozawa, Misaki; Kob, Walter

2018-05-17

The physical behavior of glass-forming liquids presents complex features of both dynamic and thermodynamic nature. Some studies indicate the presence of thermodynamic anomalies and of crossovers in the dynamic properties, but their origin and degree of universality is difficult to assess. Moreover, conventional simulations are barely able to cover the range of temperatures at which these crossovers usually occur. To address these issues, we simulate the Kob-Andersen Lennard-Jones mixture using efficient protocols based on multi-CPU and multi-GPU parallel tempering. Our setup enables us to probe the thermodynamics and dynamics of the liquid at equilibrium well below the critical temperature of the mode-coupling theory, [Formula: see text]. We find that below [Formula: see text] the analysis is hampered by partial crystallization of the metastable liquid, which nucleates extended regions populated by large particles arranged in an fcc structure. By filtering out crystalline samples, we reveal that the specific heat grows in a regular manner down to [Formula: see text] . Possible thermodynamic anomalies suggested by previous studies can thus occur only in a region of the phase diagram where the system is highly metastable. Using the equilibrium configurations obtained from the parallel tempering simulations, we perform molecular dynamics and Monte Carlo simulations to probe the equilibrium dynamics down to [Formula: see text]. A temperature-derivative analysis of the relaxation time and diffusion data allows us to assess different dynamic scenarios around [Formula: see text]. Hints of a dynamic crossover come from analysis of the four-point dynamic susceptibility. Finally, we discuss possible future numerical strategies to clarify the nature of crossover phenomena in glass-forming liquids.

The unusual magnetism of nanoparticle LaCoO3.

PubMed

Durand, A M; Belanger, D P; Hamil, T J; Ye, F; Chi, S; Fernandez-Baca, J A; Booth, C H; Abdollahian, Y; Bhat, M

2015-05-08

Bulk and nanoparticle powders of LaCoO3 (LCO) were synthesized and their magnetic and structural properties were studied using SQUID magnetometry and neutron diffraction. The bulk and large nanoparticles exhibit weak ferromagnetism (FM) below T ≈ 85 K and a crossover from strong to weak antiferromagnetic (AFM) correlations near a transition expressed in the lattice parameters, To≈40 K. This crossover does not occur in the smallest nanoparticles; instead, the magnetic behavior is predominantly ferromagnetic. The amount of FM in the nanoparticles depends on the amount of Co3O4 impurity phase, which induces tensile strain on the LCO lattice. A core-interface model is introduced, with the core region exhibiting the AFM crossover and with FM in the interface region near surfaces and impurity phases.

The unusual magnetism of nanoparticle LaCoO 3

DOE PAGES

Durand, A. M.; Belanger, D. P.; Hamil, T. J.; ...

2015-04-15

Bulk and nanoparticle powders of LaCoO 3 (LCO) were synthesized and their magnetic and structural properties were studied using SQUID magnetometry and neutron diffraction. The bulk and large nanoparticles exhibit weak ferromagnetism (FM) below T≈85K and a crossover from strong to weak antiferromagnetic (AFM) correlations near a transition expressed in the lattice parameters, To ≈ 40 K. This crossover does not occur in the smallest nanoparticles; instead, the magnetic behavior is predominantly ferromagnetic. The amount of FM in the nanoparticles depends on the amount of Co 3O 4 impurity phase, which induces tensile strain on the LCO lattice. A core-interfacemore » model is introduced, with the core region exhibiting the AFM crossover and with FM in the interface region near surfaces and impurity phases.« less

The unusual magnetism of nanoparticle LaCoO3

NASA Astrophysics Data System (ADS)

Durand, A. M.; Belanger, D. P.; Hamil, T. J.; Ye, F.; Chi, S.; Fernandez-Baca, J. A.; Booth, C. H.; Abdollahian, Y.; Bhat, M.

2015-05-01

Bulk and nanoparticle powders of LaCoO3 (LCO) were synthesized and their magnetic and structural properties were studied using SQUID magnetometry and neutron diffraction. The bulk and large nanoparticles exhibit weak ferromagnetism (FM) below T ≈ 85 K and a crossover from strong to weak antiferromagnetic (AFM) correlations near a transition expressed in the lattice parameters, To≈40 K. This crossover does not occur in the smallest nanoparticles; instead, the magnetic behavior is predominantly ferromagnetic. The amount of FM in the nanoparticles depends on the amount of Co3O4 impurity phase, which induces tensile strain on the LCO lattice. A core-interface model is introduced, with the core region exhibiting the AFM crossover and with FM in the interface region near surfaces and impurity phases.

Dynamical Crossovers in Prethermal Critical States.

PubMed

Chiocchetta, Alessio; Gambassi, Andrea; Diehl, Sebastian; Marino, Jamir

2017-03-31

We study the prethermal dynamics of an interacting quantum field theory with an N-component order parameter and O(N) symmetry, suddenly quenched in the vicinity of a dynamical critical point. Depending on the initial conditions, the evolution of the order parameter, and of the response and correlation functions, can exhibit a temporal crossover between universal dynamical scaling regimes governed, respectively, by a quantum and a classical prethermal fixed point, as well as a crossover from a Gaussian to a non-Gaussian prethermal dynamical scaling. Together with a recent experiment, this suggests that quenches may be used in order to explore the rich variety of dynamical critical points occurring in the nonequilibrium dynamics of a quantum many-body system. We illustrate this fact by using a combination of renormalization group techniques and a nonperturbative large-N limit.

Influence diagnostics for count data under AB-BA crossover trials.

PubMed

Hao, Chengcheng; von Rosen, Dietrich; von Rosen, Tatjana

2017-12-01

This paper aims to develop diagnostic measures to assess the influence of data perturbations on estimates in AB-BA crossover studies with a Poisson distributed response. Generalised mixed linear models with normally distributed random effects are utilised. We show that in this special case, the model can be decomposed into two independent sub-models which allow to derive closed-form expressions to evaluate the changes in the maximum likelihood estimates under several perturbation schemes. The performance of the new influence measures is illustrated by simulation studies and the analysis of a real dataset.

49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

Code of Federal Regulations, 2011 CFR

2011-10-01

...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which...

49 CFR 218.103 - Hand-operated switches, including crossover switches.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...

49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which...

49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which...

49 CFR 218.103 - Hand-operated switches, including crossover switches.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...

49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which...

49 CFR 218.103 - Hand-operated switches, including crossover switches.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...

49 CFR 218.103 - Hand-operated switches, including crossover switches.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...

49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which...

49 CFR 218.103 - Hand-operated switches, including crossover switches.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...

Metal-like transport in proteins: A new paradigm for biological electron transfer

NASA Astrophysics Data System (ADS)

Malvankar, Nikhil; Vargas, Madeline; Tuominen, Mark; Lovley, Derek

2012-02-01

Electron flow in biologically proteins generally occurs via tunneling or hopping and the possibility of electron delocalization has long been discounted. Here we report metal-like transport in protein nanofilaments, pili, of bacteria Geobacter sulfurreducens that challenges this long-standing belief [1]. Pili exhibit conductivities comparable to synthetic organic metallic nanostructures. The temperature, magnetic field and gate-voltage dependence of pili conductivity is akin to that of quasi-1D disordered metals, suggesting a metal-insulator transition. Magnetoresistance (MR) data provide evidence for quantum interference and weak localization at room temperature, as well as a temperature and field-induced crossover from negative to positive MR. Furthermore, pili can be doped with protons. Structural studies suggest the possibility of molecular pi stacking in pili, causing electron delocalization. Reducing the disorder increases the metallic nature of pili. These electronically functional proteins are a new class of electrically conductive biological proteins that can be used to generate future generation of inexpensive and environmentally-sustainable nanomaterials and nanolectronic devices such as transistors and supercapacitors. [1] Malvankar et al. Nature Nanotechnology, 6, 573-579 (2011)

Comparison of the urinary excretion of quercetin glycosides from red onion and aglycone from dietary supplements in healthy subjects: a randomized, single-blinded, cross-over study.

PubMed

Shi, Yuanlu; Williamson, Gary

2015-05-01

Some intervention studies have shown that quercetin supplementation can regulate certain biomarkers, but it is not clear how the doses given relate to dietary quercetin (e.g. from onion). We conducted a two-period, two-sequence crossover study to compare the bioavailability of quercetin when administered in the form of a fresh red onion meal (naturally glycosylated quercetin) or dietary supplement (aglycone quercetin) under fasting conditions. Six healthy, non-smoking, adult males with BMI 22.7 ± 4.0 kg m(-2) and age 35.3 ± 12.3 y were grouped to take the two study meals in random order. In each of the 2 study periods, one serving of onion soup (made from 100 g fresh red onion, providing 156.3 ± 3.4 μmol (47 mg) quercetin) or a single dose of a quercetin dihydrate tablet (1800 ± 150 μmol (544 mg) of quercetin) were administered following 3 d washout. Urine samples were collected up to 24 h, and after enzyme deconjugation, quercetin was quantified by LC-MS. The 24 h urinary excretion of quercetin (1.69 ± 0.79 μmol) from red onion in soup was not significantly different to that (1.17 ± 0.44 μmol) for the quercetin supplement tablet (P = 0.065, paired t-test). This means that, in practice, 166 mg of quercetin supplement would be comparable to about 10 mg of quercetin aglycone equivalents from onion. These data allow intervention studies on quercetin giving either food or supplements to be more effectively compared.

Does the Flipped Classroom Improve Learning in Graduate Medical Education?

PubMed

Riddell, Jeff; Jhun, Paul; Fung, Cha-Chi; Comes, James; Sawtelle, Stacy; Tabatabai, Ramin; Joseph, Daniel; Shoenberger, Jan; Chen, Esther; Fee, Christopher; Swadron, Stuart P

2017-08-01

The flipped classroom model for didactic education has recently gained popularity in medical education; however, there is a paucity of performance data showing its effectiveness for knowledge gain in graduate medical education. We assessed whether a flipped classroom module improves knowledge gain compared with a standard lecture. We conducted a randomized crossover study in 3 emergency medicine residency programs. Participants were randomized to receive a 50-minute lecture from an expert educator on one subject and a flipped classroom module on the other. The flipped classroom included a 20-minute at-home video and 30 minutes of in-class case discussion. The 2 subjects addressed were headache and acute low back pain. A pretest, immediate posttest, and 90-day retention test were given for each subject. Of 82 eligible residents, 73 completed both modules. For the low back pain module, mean test scores were not significantly different between the lecture and flipped classroom formats. For the headache module, there were significant differences in performance for a given test date between the flipped classroom and the lecture format. However, differences between groups were less than 1 of 10 examination items, making it difficult to assign educational importance to the differences. In this crossover study comparing a single flipped classroom module with a standard lecture, we found mixed statistical results for performance measured by multiple-choice questions. As the differences were small, the flipped classroom and lecture were essentially equivalent.

Association of Ambient Fine Particles With Out-of-Hospital Cardiac Arrests in New York City

PubMed Central

Silverman, Robert A.; Ito, Kazuhiko; Freese, John; Kaufman, Brad J.; De Claro, Danilynn; Braun, James; Prezant, David J.

2010-01-01

Cardiovascular morbidity has been associated with particulate matter (PM) air pollution, although the relation between pollutants and sudden death from cardiac arrest has not been established. This study examined associations between out-of-hospital cardiac arrests and fine PM (of aerodynamic diameter ≤2.5 μm, or PM2.5), ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide in New York City. The authors analyzed 8,216 out-of-hospital cardiac arrests of primary cardiac etiology during the years 2002–2006. Time-series and case-crossover analyses were conducted, controlling for season, day-of-week, same-day, and delayed/apparent temperature. An increased risk of cardiac arrest in time-series (relative risk (RR) = 1.06, 95% confidence interval (CI): 1.02, 1.10) and case-crossover (RR = 1.04, 95% CI: 0.99, 1.08) analysis for a PM2.5 increase of 10 μg/m3 in the average of 0- and 1-day lags was found. The association was significant in the warm season (RR = 1.09, 95% CI: 1.03, 1.15) but not the cold season (RR = 1.01, 95% CI: 0.95, 1.07). Associations of cardiac arrest with other pollutants were weaker. These findings, consistent with studies implicating acute cardiovascular effects of PM, support a link between PM2.5 and out-of-hospital cardiac arrests. Since few individuals survive an arrest, air pollution control may help prevent future cardiovascular mortality. PMID:20729350

A randomized, placebo-controlled trial of controlled release melatonin treatment of delayed sleep phase syndrome and impaired sleep maintenance in children with neurodevelopmental disabilities.

PubMed

Wasdell, Michael B; Jan, James E; Bomben, Melissa M; Freeman, Roger D; Rietveld, Wop J; Tai, Joseph; Hamilton, Donald; Weiss, Margaret D

2008-01-01

The purpose of this study was to determine the efficacy of controlled-release (CR) melatonin in the treatment of delayed sleep phase syndrome and impaired sleep maintenance of children with neurodevelopmental disabilities including autistic spectrum disorders. A randomized double-blind, placebo-controlled crossover trial of CR melatonin (5 mg) followed by a 3-month open-label study was conducted during which the dose was gradually increased until the therapy showed optimal beneficial effects. Sleep characteristics were measured by caregiver who completed somnologs and wrist actigraphs. Clinician rating of severity of the sleep disorder and improvement from baseline, along with caregiver ratings of global functioning and family stress were also obtained. Fifty-one children (age range 2-18 years) who did not respond to sleep hygiene intervention were enrolled. Fifty patients completed the crossover trial and 47 completed the open-label phase. Recordings of total night-time sleep and sleep latency showed significant improvement of approximately 30 min. Similarly, significant improvement was observed in clinician and parent ratings. There was additional improvement in the open-label somnolog measures of sleep efficiency and the longest sleep episode in the open-label phase. Overall, the therapy improved the sleep of 47 children and was effective in reducing family stress. Children with neurodevelopmental disabilities, who had treatment resistant chronic delayed sleep phase syndrome and impaired sleep maintenance, showed improvement in melatonin therapy.

The Biphasic Effects of Moderate Alcohol Consumption with a Meal on Ambiance-Induced Mood and Autonomic Nervous System Balance: A Randomized Crossover Trial

PubMed Central

Schrieks, Ilse C.; Stafleu, Annette; Kallen, Victor L.; Grootjen, Marc; Witkamp, Renger F.; Hendriks, Henk F. J.

2014-01-01

Background The pre-drinking mood state has been indicated to be an important factor in the mood effects of alcohol. However, for moderate alcohol consumption there are no controlled studies showing this association. Also, the mood effects of consuming alcohol combined with food are largely unknown. The aim of this study was to investigate the effects of moderate alcohol combined with a meal on ambiance-induced mood states. Furthermore effects on autonomic nervous system activity were measured to explore physiological mechanisms that may be involved in changes of mood state. Methods In a crossover design 28 women (age 18–45 y, BMI 18.5–27 kg/m2) were randomly allocated to 4 conditions in which they received 3 glasses of sparkling white wine (30 g alcohol) or alcohol-free sparkling white wine while having dinner in a room with either a pleasant or unpleasant created ambiance. Subjects filled out questionnaires (B-BAES, POMS and postprandial wellness questionnaire) at different times. Skin conductance and heart rate variability were measured continuously. Results Moderate alcohol consumption increased happiness scores in the unpleasant, but not in the pleasant ambiance. Alcohol consumption increased happiness and stimulation feelings within 1 hour and increased sedative feelings and sleepiness for 2.5 hour. Skin conductance was increased after alcohol within 1 hour and was related to happiness and stimulation scores. Heart rate variability was decreased after alcohol for 2 hours and was related to mental alertness. Conclusion Mood inductions and autonomic nervous system parameters may be useful to evaluate mood changes by nutritional interventions. Moderate alcohol consumption elevates happiness scores in an unpleasant ambiance. However, drinking alcohol during a pleasant mood results in an equally positive mood state. Trial Registration Clinicaltrials.gov NCT01426022. PMID:24465955

The Value of Supplementing Science Education with Outdoor Instruction for Sixth Grade Students

NASA Astrophysics Data System (ADS)

Jackson, Devin Joseph Guilford

Science education is moving away from memorization of facts to inquiry based learning. Adding outdoor instruction can be an effective way to promote this exploratory method of learning. The limited number of empirical studies available have shown significant increase in attitudes and learning with outdoor science instruction. An eight-week quasi-experimental teacher research study was conducted to further this research and assess the value of schoolyard science instruction on student engagement and learning. Participants were 60 students in two sixth grade middle school Earth Science classes. A crossover study design was used with two classes alternating as experimental and control groups. NASA Global Precipitation Measurement mission curriculum was used (NASA/GPM, 2011). While the results did not show a clear increase in student engagement and content knowledge, the study adds to the body of knowledge on outdoor instruction and identifies limitations to consider in future studies.

Electromagnetic pump stator frame having power crossover struts

DOEpatents

Fanning, Alan W.; Olich, Eugene E.

1995-01-01

A stator frame for an electromagnetic pump includes a casing joined to a hub by a plurality of circumferentially spaced apart struts. At least one electrically insulated power crossover lead extends through the hub, through a crossover one of the struts, and through the casing for carrying electrical current therethrough.

50 CFR 660.320 - Open access fishery-crossover provisions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. (a) Operating in both limited entry and open access fisheries. See provisions at § 660.60, subpart C. (b...

50 CFR 660.320 - Open access fishery-crossover provisions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. (a) Operating in both limited entry and open access fisheries. See provisions at § 660.60, subpart C. (b...

Determination of Effective Crossover Location and Dimensions for Branched Detonation in a Pulsed Detonation Engine

DTIC Science & Technology

2012-03-22

location is varied from the aft end of the detonation tube to the middle of the detonation tube while the crossover width is varied from 2.5 in to 0.5...the other end where the tube is connected to a source of fuel, oxidizer, and ignition .7 The engine cycle is divided into three equal phases: fill...location and width of the crossover duct for hydrogen, ethylene and an n-alkane. The crossover location is varied from the aft end of the

Spin crossover in (Mg,Fe3+)(Si,Fe3+)O3 bridgmanite: effects of disorder, iron concentration, and temperature

NASA Astrophysics Data System (ADS)

Shukla, Gaurav; Wentzcovitch, Renata

The spin crossover of iron in Fe3+-bearing bridgmanite, the most abundant mineral of the Earth's lower mantle, is by now a well-established phenomenon, though several aspects of this crossover remain unclear. Here we investigate effects of disorder, iron concentration, and temperature on this crossover using ab initio LDA + USC calculations. Disorder and concentration effects are addressed using complete statistical samplings of coupled substituted configurations up to 80 atoms supercells, while the vibrational effects using the quasiharmonic approximation. Our calculated compression curves for iron-free and iron-bearing bridgmanite compare well with the latest experimental measurements. The comparison also suggests that in a closed system, Fe2+ present in the sample may transform into Fe3+ by introduction of Mg and O vacancies with increasing pressure. As in the spin crossover in ferropericlase, this crossover in bridgmanite is accompanied by a clear volume reduction and an anomalous softening of the bulk modulus throughout the crossover pressure range. Though the concentration of [Fe3+]Si in bridgmanite may be small, related elastic anomalies may impact the interpretation of radial and lateral velocity structures of the Earth's lower mantle. This research was supported primarily by NSF Grant EAR 1348066. Computations are performed at the Minnesota Supercomputing Institute (MSI).

Modafinil In Debilitating fatigue After Stroke (MIDAS): study protocol for a randomised, double-blinded, placebo-controlled, crossover trial.

PubMed

Lillicrap, Thomas; Krishnamurthy, Venkatesh; Attia, John; Nilsson, Michael; Levi, Christopher R; Parsons, Mark W; Bivard, Andrew

2016-08-17

Fatigue is a common symptom in stroke survivors for which there is currently no proven therapy. Modafinil is a wakefulness-promoting agent with established benefits in other disease models. We aim to test if modafinil will improve patient's self-reported fatigue scores when compared to placebo and if therapy results in increased quality of life. MIDAS is a phase II, single-centre, prospective, double-blinded, randomised, crossover trial of modafinil for the treatment of persistent fatigue in survivors of ischaemic stroke. The inclusion criteria will require an average score of 12 or more across all domains of the Multi-dimensional Fatigue Inventory (MFI-20) and the diagnosis of a stroke more than 6 months prior. Patients will be randomised 1:1 to receive either modafinil 200 mg daily or placebo for a period of 6 weeks, after which a crossover will occur where patients who are on modafinil will begin taking placebo and vice versa. The primary outcome will be improvement in fatigue as measured by the MFI-20. Secondary outcomes will include changes in the Fatigue Severity Scale, improved cognition measured using the Montreal Cognitive Assessment, improvement in mood as determined by the Depression, Anxiety and Stress Scale and improvement in each patient's stroke-specific quality of life score. All participants will also undergo magnetic resonance imaging (MRI) at baseline, crossover and study conclusion to measure cerebral blood flow on arterial spin labelling and brain activity on resting state functional MRI. This study will comply with the CONSORT guidelines. The projected sample size requirement is 36 participants in a crossover trial giving a power of 80 % and a type-1 error rate of 0.05. MIDAS seeks to enhance the quality of life in stroke survivors by assisting or resolving stroke-associated fatigue. ACTRN12615000350527 , registered on the 17 April 2015. Protocol version 3, approved 16 June 2015.

A crossover-crossback prospective study of dibutyl-phthalate exposure from mesalamine medications and serum reproductive hormones in men.

PubMed

Nassan, Feiby L; Coull, Brent A; Skakkebaek, Niels E; Andersson, Anna-Maria; Williams, Michelle A; Mínguez-Alarcón, Lidia; Krawetz, Stephen A; Hall, Janet E; Hait, Elizabeth J; Korzenik, Joshua R; Ford, Jennifer B; Moss, Alan C; Hauser, Russ

2018-01-01

Phthalates, such as dibutyl phthalate (DBP), are endocrine disruptors used in some medication coatings e.g., mesalamine to treat inflammatory bowel disease (IBD). Taking advantage of different mesalamine formulations with/without DBP, we assessed whether DBP from mesalamine (>1000x background) altered serum hormones. Men (N=73) with IBD participated in a crossover-crossback prospective study and provided up to 6 serum samples (2:baseline, 2:crossover, 2:crossback). Men on non-DBP mesalamine (background) at baseline crossed-over for 4 months to DBP-mesalamine (high) and then crossed-back for 4 months to non-DBP mesalamine (B 1 HB 2 -arm) and vice versa for men on DBP-mesalamine at baseline (H 1 BH 2 -arm). We divided H 1 BH 2 -arm at the median (H 1 <3yrs or H 1 ≥3yrs). We estimated crossover and crossback % changes in serum reproductive hormones using multivariable linear mixed effect models. When B 1 HB 2 -arm (26 men,134 samples) crossed-over, luteinizing hormone decreased 13.9% (95% confidence interval(CI): -23.6,-3.0) and testosterone, inhibin-B, and follicle-stimulating hormone (FSH) marginally decreased; after crossback all increased 8-14%. H 1 BH 2 -arm, H 1 ≥3yrs (25 men,107samples) had no changes at crossover or crossback whereas in H 1 BH 2 -arm,H 1 <3yrs (22 men,100 samples) after crossover, inhibin-B increased 13.2% (CI: 4.2,22.9), FSH decreased 9.9% (CI: -17.9,-1.1) and after crossback, inhibin-B further increased 11.3%, and FSH marginally increased. High-DBP exposure may disrupt pituitary-gonadal hormones that largely reversed after exposure removal, but only in men with no or short previous high-exposure history. Paradoxically, men with longer duration of high-DBP exposure, exposure removal did not change hormone levels, suggesting that long-term high-DBP exposure may alter the pituitary-gonadal axis and make it insensitive to exposure changes. Copyright © 2017 Elsevier Inc. All rights reserved.

The role of crossover operator in evolutionary-based approach to the problem of genetic code optimization.

PubMed

Błażej, Paweł; Wnȩtrzak, Małgorzata; Mackiewicz, Paweł

2016-12-01

One of theories explaining the present structure of canonical genetic code assumes that it was optimized to minimize harmful effects of amino acid replacements resulting from nucleotide substitutions and translational errors. A way to testify this concept is to find the optimal code under given criteria and compare it with the canonical genetic code. Unfortunately, the huge number of possible alternatives makes it impossible to find the optimal code using exhaustive methods in sensible time. Therefore, heuristic methods should be applied to search the space of possible solutions. Evolutionary algorithms (EA) seem to be ones of such promising approaches. This class of methods is founded both on mutation and crossover operators, which are responsible for creating and maintaining the diversity of candidate solutions. These operators possess dissimilar characteristics and consequently play different roles in the process of finding the best solutions under given criteria. Therefore, the effective searching for the potential solutions can be improved by applying both of them, especially when these operators are devised specifically for a given problem. To study this subject, we analyze the effectiveness of algorithms for various combinations of mutation and crossover probabilities under three models of the genetic code assuming different restrictions on its structure. To achieve that, we adapt the position based crossover operator for the most restricted model and develop a new type of crossover operator for the more general models. The applied fitness function describes costs of amino acid replacement regarding their polarity. Our results indicate that the usage of crossover operators can significantly improve the quality of the solutions. Moreover, the simulations with the crossover operator optimize the fitness function in the smaller number of generations than simulations without this operator. The optimal genetic codes without restrictions on their structure minimize the costs about 2.7 times better than the canonical genetic code. Interestingly, the optimal codes are dominated by amino acids characterized by polarity close to its average value for all amino acids. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

12-month blood pressure results of catheter-based renal artery denervation for resistant hypertension: the SYMPLICITY HTN-3 trial.

PubMed

Bakris, George L; Townsend, Raymond R; Flack, John M; Brar, Sandeep; Cohen, Sidney A; D'Agostino, Ralph; Kandzari, David E; Katzen, Barry T; Leon, Martin B; Mauri, Laura; Negoita, Manuela; O'Neill, William W; Oparil, Suzanne; Rocha-Singh, Krishna; Bhatt, Deepak L

2015-04-07

Results of the SYMPLICITY HTN-3 (Renal Denervation in Patients With Uncontrolled Hypertension) trial confirmed the safety but not the efficacy of renal denervation for treatment-resistant hypertension at 6 months post procedure. This study sought to analyze the 12-month SYMPLICITY HTN-3 results for the original denervation group, the sham subjects who underwent denervation after the 6-month endpoint (crossover group), and the sham subjects who did not undergo denervation after 6 months (non-crossover group). Eligible subjects were randomized 2:1 to denervation or sham procedure. Subjects were unblinded to their treatment group after the 6-month primary endpoint was ascertained; subjects in the sham group meeting eligibility requirements could undergo denervation. Change in blood pressure (BP) at 12 months post randomization (6 months for crossover subjects) was analyzed. The 12-month follow-up was available for 319 of 361 denervation subjects and 48 of 101 non-crossover subjects; 6-month denervation follow-up was available for 93 of 101 crossover subjects. In denervation subjects, the 12-month office systolic BP (SBP) change was greater than that observed at 6 months (-15.5 ± 24.1 mm Hg vs. -18.9 ± 25.4 mm Hg, respectively; p = 0.025), but the 24-h SBP change was not significantly different at 12 months (p = 0.229). The non-crossover group office SBP decreased by -32.9 ± 28.1 mm Hg at 6 months, but this response regressed to -21.4 ± 19.9 mm Hg (p = 0.01) at 12 months, increasing to 11.5 ± 29.8 mm Hg. These data support no further reduction in office or ambulatory BP after 1-year follow-up. Loss of BP reduction in the non-crossover group may reflect decreased medication adherence or other related factors. (Renal Denervation in Patients With Uncontrolled Hypertension [SYMPLICITY HTN-3]; NCT01418261). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Analytical Description of Degradation-Relaxation Transformations in Nanoinhomogeneous Spinel Ceramics.

PubMed

Shpotyuk, O; Brunner, M; Hadzaman, I; Balitska, V; Klym, H

2016-12-01

Mathematical models of degradation-relaxation kinetics are considered for jammed thick-film systems composed of screen-printed spinel Cu 0.1 Ni 0.1 Co 1.6 Mn 1.2 O 4 and conductive Ag or Ag-Pd alloys. Structurally intrinsic nanoinhomogeneous ceramics due to Ag and Ag-Pd diffusing agents embedded in a spinel phase environment are shown to define governing kinetics of thermally induced degradation under 170 °C obeying an obvious non-exponential behavior in a negative relative resistance drift. The characteristic stretched-to-compressed exponential crossover is detected for degradation-relaxation kinetics in thick-film systems with conductive contacts made of Ag-Pd and Ag alloys. Under essential migration of a conductive phase, Ag penetrates thick-film spinel ceramics via a considerable two-step diffusing process.

Higher-than-ballistic conduction of viscous electron flows.

PubMed

Guo, Haoyu; Ilseven, Ekin; Falkovich, Gregory; Levitov, Leonid S

2017-03-21

Strongly interacting electrons can move in a neatly coordinated way, reminiscent of the movement of viscous fluids. Here, we show that in viscous flows, interactions facilitate transport, allowing conductance to exceed the fundamental Landauer's ballistic limit [Formula: see text] The effect is particularly striking for the flow through a viscous point contact, a constriction exhibiting the quantum mechanical ballistic transport at [Formula: see text] but governed by electron hydrodynamics at elevated temperatures. We develop a theory of the ballistic-to-viscous crossover using an approach based on quasi-hydrodynamic variables. Conductance is found to obey an additive relation [Formula: see text], where the viscous contribution [Formula: see text] dominates over [Formula: see text] in the hydrodynamic limit. The superballistic, low-dissipation transport is a generic feature of viscous electronics.

Do Surrogate Endpoints Better Correlate with Overall Survival in Studies That Did Not Allow for Crossover or Reported Balanced Postprogression Treatments? An Application in Advanced Non-Small Cell Lung Cancer.

PubMed

Hashim, Mahmoud; Pfeiffer, Boris M; Bartsch, Robert; Postma, Maarten; Heeg, Bart

2018-01-01

In previous studies, correlation between overall survival (OS) and surrogate endpoints like objective response rate (ORR) or progression-free survival (PFS) in advanced non-small cell lung cancer (NSCLC) was poor. This can be biased by crossover and postprogression treatments. To evaluate the relationship between these two surrogate endpoints and OS in advanced NSCLC studies that did not allow for crossover or reported balanced post-progression treatments. A systematic review in patients with advanced NSCLC receiving second- and further-line therapy was performed. The relationship between the absolute difference in ORR or median PFS (mPFS) and the absolute difference in median OS (mOS) was assessed using the correlation coefficient (R) and weighted regression models. The analysis was repeated in predefined data cuts based on crossover and balance of postprogression treatments. When the upper limit of R's 95% confidence interval (CI) was more than 0.7, the surrogate threshold effect (STE) was estimated. In total, 146 randomized clinical trials (43,061 patients) were included. The mean ORR, mPFS, and mOS were 12.2% ± 11.2%, 3.2 ± 1.3 months, and 9.6 ± 4.1 months, respectively. The correlation coefficients of ORR and mPFS were 0.181 (95% CI 0.016-0.337) and 0.254 (95% CI 0.074-0.418), respectively, with mOS. Nevertheless, in trials that did not allow crossover and reported balanced postprogression treatments, the correlation coefficients of ORR and mPFS were 0.528 (95% CI 0.081-0.798) and 0.778 (95% CI 0.475-0.916), respectively, with mOS. On the basis of STE estimation, in trials showing significant treatment effect size of 41.0% or more ORR or 4.15 or more mPFS months, OS benefit can be expected with sufficient certainty. Crossover and postprogression treatments may bias the relationship between surrogate endpoints and OS. Presented STE calculation can be used to interpret treatment effect on either ORR or PFS when used as primary endpoints. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Lack of a Pharmacokinetic Interaction Between Saxagliptin and Dapagliflozin in Healthy Subjects: A Randomized Crossover Study.

PubMed

Vakkalagadda, Blisse; Lubin, Susan; Reynolds, Laurie; Liang, Dan; Marion, Alan S; LaCreta, Frank; Boulton, David W

2016-08-01

This single-dose, open-label, randomized, 3-period, 3-treatment crossover drug-drug interaction study was conducted to evaluate differences in the pharmacokinetic properties of saxagliptin and dapagliflozin when coadministered. Healthy subjects (N = 42) were randomized to receive saxagliptin 5 mg alone, dapagliflozin 10 mg alone, or saxagliptin 5 mg plus dapagliflozin 10 mg coadministered; there was a washout period of ≥6 days between treatments. Serial blood samples for determining saxagliptin, 5-hydroxy saxagliptin (5-OH saxagliptin; major active metabolite) and dapagliflozin plasma concentrations and pharmacokinetic parameters were collected before and up to 60 hours after the dose. No interaction was to be concluded if the 90% CIs for the geometric mean ratios of the combination compared with each drug given alone for Cmax and AUCinf were within 0.80 to 1.25. The results indicated that dapagliflozin had no effect on the pharmacokinetic properties of saxagliptin, 5-OH saxagliptin, or saxagliptin total active moiety and vice versa. The 90% CIs for Cmax and AUCinf for all comparisons were contained entirely within the 0.80 to 1.25 equivalence intervals. Other pharmacokinetic parameters (apparent oral clearance or half-life) of saxagliptin or dapagliflozin were similar when each medicine was administered alone or when coadministered. No safety profile or tolerability findings of concern were observed during the study. All adverse events were mild, and no serious adverse events were reported. These data indicate that coadministration of saxagliptin and dapagliflozin exhibits no pharmacokinetic interaction and is well tolerated. ClinicalTrials.gov identifier: NCT01662999. Copyright © 2016 Elsevier HS Journals, Inc. All rights reserved.

Acute changes of hip joint range of motion using selected clinical stretching procedures: A randomized crossover study.

PubMed

Hammer, Adam M; Hammer, Roger L; Lomond, Karen V; O'Connor, Paul

2017-12-01

Hip adductor flexibility and strength is an important component of athletic performance and many activities of daily living. Little research has been done on the acute effects of a single session of stretching on hip abduction range of motion (ROM). The aim of this study was to compare 3 clinical stretching procedures against passive static stretching and control on ROM and peak isometric maximal voluntary contraction (MVC). Using a randomized crossover study design, a total of 40 participants (20 male and 20 female) who had reduced hip adductor muscle length attended a familiarization session and 5 testing sessions on non-consecutive days. Following the warm-up and pre-intervention measures of ROM and MVC, participants were randomly assigned 1 of 3 clinical stretching procedures (modified lunge, multidirectional, and joint mobilization) or a static stretch or control condition. Post-intervention measures of ROM and MVC were taken immediately following completion of the assigned condition. An ANOVA using a repeated measure design with the change score was conducted. All interventions resulted in small but statistically significant (p < 0.05) increases (1.0°-1.7°) in ROM with no inter-condition differences except one. Multidirectional stretching was greater than control (p = 0.031). These data suggest that a single session of stretching has only a minimal effect on acute changes of hip abduction ROM. Although hip abduction is a frontal plane motion, to effectively increase the extensibility of the structures that limit abduction, integrating multi-planar stretches may be indicated. Copyright © 2017 Elsevier Ltd. All rights reserved.

A crossover randomized prospective pilot study evaluating a central venous catheter team in reducing catheter-related bloodstream infections in pediatric oncology patients.

PubMed

Secola, Rita; Azen, Colleen; Lewis, Mary Ann; Pike, Nancy; Needleman, Jack; Sposto, Richard; Doering, Lynn

2012-01-01

Treatment for most children with cancer includes the use of a central venous catheter (CVC). CVCs provide reliable venous access for delivery of chemotherapy and supportive care. This advantage is mitigated by an increased risk of bloodstream infections (BSIs). Despite the ubiquitous use of CVCs, few prospective studies have been conducted to address infection prevention strategies in pediatric oncology patients. Prospective, crossover pilot study of a CVC team intervention versus standard care. Two inpatient oncology units in a metropolitan children's hospital. A total of 41 patients/135 admissions for the experimental unit (EU) and 41/129 admissions for the control unit (CU). Patients received a CVC blood draw bundle procedure by a CVC registered nurse (RN) team member (experimental intervention: EU) for 6 months and by the assigned bedside RN (standard care: CU) for 6 months. Feasibility of implementing a CVC RN team; a significant difference in CVC-related BSIs between the team intervention versus standard care and risk factors associated in the development of CVC-related BSIs were determined. There were 7 CVC-related BSIs/1238 catheter days in the EU group (5.7/1000 catheter days) versus 3 CVC-related BSIs/1419 catheter days in the CU group (2.1/1000 catheter days; P = .97). Selected risk factors were not significantly associated with the development of a CVC-related BSI. A CVC team in the care of pediatric oncology patients is feasible; however, a larger cohort will be required to adequately determine the effectiveness of the team reducing CVC-related BSIs.

Cognitive changes after saline or plasmalyte infusion in healthy volunteers: a multiple blinded, randomized, cross-over trial.

PubMed

Story, David A; Lees, Lucy; Weinberg, Laurence; Teoh, Soon-Yee; Lee, Katherine J; Velissaris, Sarah; Bellomo, Rinaldo; Wilson, Sarah J

2013-09-01

In an incidental finding, during a study of plasma chemistry after crystalloid infusion, participants reported subjective cognitive changes, particularly slower thinking, after saline but not Hartmann's (Ringer's lactate) solution. The authors tested the hypothesis that saline infusion would produce greater adverse cognitive changes than Plasmalyte infusion. The authors conducted a randomized, cross-over, multiple blinded study of healthy adult volunteers. On separate days, participants received 30 ml/kg over 1 h of either 0.9% saline or Plasmalyte with the order randomly allocated. Plasma chemistry was tested on venous samples. As part of a battery of cognitive tests our primary endpoint was the reaction time index after infusion. The authors studied 25 participants. Plasma chloride was greater after saline than after Plasmalyte: mean difference 5.4 mM (95% CI, 4.1-6.6 mM; P < 0.001). Saline was also associated with greater metabolic acidosis: base-excess 2.5 mM more negative (95% CI, 1.9-3.0 mM more negative; P < 0.001). There was no evidence of a difference in the reaction time index between the two interventions: mean reaction time index 394 ms (SD, 72) after saline versus 385 ms (SD, 55) after Plasmalyte. Difference: saline 9 ms slower (95% CI, 30 ms slower to 12 ms faster; P = 0.39). There were minimal differences in the other cognitive and mood tests. Despite expected differences in plasma chemistry, the authors found that measures of cognition did not differ after infusions of Plasmalyte or saline.

Association between ambient air pollution and hospitalization for ischemic and hemorrhagic stroke in China: A multicity case-crossover study.

PubMed

Liu, Hui; Tian, Yaohua; Xu, Yan; Huang, Zhe; Huang, Chao; Hu, Yonghua; Zhang, Jun

2017-11-01

There is growing interest in the association between ambient air pollution and stroke, but few studies have investigated the association in developing countries. The primary objective of this study was to examine the association between levels of ambient air pollutants and hospital admission for stroke in China. A time-stratified case-crossover analysis was conducted between 2014 and 2015 in 14 large Chinese cities among 200,958 ischemic stroke and 41,746 hemorrhagic stroke hospitalizations. We used conditional logistic regression to estimate the percentage changes in stroke admissions in relation to interquartile range increases in air pollutants. Air pollution was positively associated with ischemic stroke. A difference of an interquartile range of the 6-day average for particulate matter less than 10 μm in aerodynamic diameter, sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone corresponded to 0.7% (95% CI: 0%, 1.4%), 1.6% (95% CI: 1.0%, 2.3%), 2.6% (95% CI: 1.8%, 3.5%), 0.5% (95% CI: -0.2%, 1.1%), and 1.3% (95% CI: 0.3%, 2.3%) increases in ischemic stroke admissions, respectively. For hemorrhagic stroke, we observed the only significant association in relation to nitrogen dioxide on the current day (percentage change: 1.6%; 95% CI: 0.3%, 2.9%). Our findings contribute to the limited scientific literature concerning the effect of ambient air pollution on stroke in developing countries. Our findings may have significant public health implications for primary prevention of stroke in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

-Sb Glasses at Low Temperatures

NASA Astrophysics Data System (ADS)

Souri, Dariush; Azizpour, Parvin; Zaliani, Hamideh

2014-09-01

Semiconducting glasses of the type 40TeO2-(60 - x) V2O5- xSb were prepared by rapid melt quenching and their dc electrical conductivity was measured in the temperature range 180-296 K. For these glassy samples, the dc electrical conductivity ranged from 2.26 × 10-7 S cm-1 to 1.11 × 10-5 S cm-1 at 296 K, indicating the conductivity is enhanced by increasing the V2O5 content. These experimental results could be explained on the basis of different mechanisms (based on polaron-hopping theory) in the different temperature regions. At temperatures above Θ D/2 (where Θ D is the Debye temperature), the non-adiabatic small polaron hopping (NASPH) model is consistent with the data, whereas at temperatures below Θ D/2, a T -1/4 dependence of the conductivity indicative of the variable range hopping (VRH) mechanism is dominant. For all these glasses crossover from SPH to VRH conduction was observed at a characteristic temperature T R ≤ Θ D/2. In this study, the hopping carrier density and carrier mobility were determined at different temperatures. N ( E F), the density of states at (or near) the Fermi level, was also determined from the Mott variables; the results were dependent on V2O5 content.

Automatic Combination of Operators in a Genetic Algorithm to Solve the Traveling Salesman Problem.

PubMed

Contreras-Bolton, Carlos; Parada, Victor

2015-01-01

Genetic algorithms are powerful search methods inspired by Darwinian evolution. To date, they have been applied to the solution of many optimization problems because of the easy use of their properties and their robustness in finding good solutions to difficult problems. The good operation of genetic algorithms is due in part to its two main variation operators, namely, crossover and mutation operators. Typically, in the literature, we find the use of a single crossover and mutation operator. However, there are studies that have shown that using multi-operators produces synergy and that the operators are mutually complementary. Using multi-operators is not a simple task because which operators to use and how to combine them must be determined, which in itself is an optimization problem. In this paper, it is proposed that the task of exploring the different combinations of the crossover and mutation operators can be carried out by evolutionary computing. The crossover and mutation operators used are those typically used for solving the traveling salesman problem. The process of searching for good combinations was effective, yielding appropriate and synergic combinations of the crossover and mutation operators. The numerical results show that the use of the combination of operators obtained by evolutionary computing is better than the use of a single operator and the use of multi-operators combined in the standard way. The results were also better than those of the last operators reported in the literature.

Automatic Combination of Operators in a Genetic Algorithm to Solve the Traveling Salesman Problem

PubMed Central

2015-01-01

Genetic algorithms are powerful search methods inspired by Darwinian evolution. To date, they have been applied to the solution of many optimization problems because of the easy use of their properties and their robustness in finding good solutions to difficult problems. The good operation of genetic algorithms is due in part to its two main variation operators, namely, crossover and mutation operators. Typically, in the literature, we find the use of a single crossover and mutation operator. However, there are studies that have shown that using multi-operators produces synergy and that the operators are mutually complementary. Using multi-operators is not a simple task because which operators to use and how to combine them must be determined, which in itself is an optimization problem. In this paper, it is proposed that the task of exploring the different combinations of the crossover and mutation operators can be carried out by evolutionary computing. The crossover and mutation operators used are those typically used for solving the traveling salesman problem. The process of searching for good combinations was effective, yielding appropriate and synergic combinations of the crossover and mutation operators. The numerical results show that the use of the combination of operators obtained by evolutionary computing is better than the use of a single operator and the use of multi-operators combined in the standard way. The results were also better than those of the last operators reported in the literature. PMID:26367182

Temperature and frequency dependent conductivity of bismuth zinc vanadate semiconducting glassy system

NASA Astrophysics Data System (ADS)

Punia, R.; Kundu, R. S.; Dult, Meenakshi; Murugavel, S.; Kishore, N.

2012-10-01

The ac conductivity of bismuth zinc vanadate glasses with compositions 50V2O5. xBi2O3. (50-x) ZnO has been studied in the frequency range 10-1 Hz to 2 MHz and in temperature range 333.16 K to 533.16 K. The temperature and frequency dependent conductivity is found to obey Jonscher's universal power law for all the compositions of bismuth zinc vanadate glass system. The dc conductivity (σdc), crossover frequency (ωH), and frequency exponent (s) have been estimated from the fitting of experimental data of ac conductivity with Jonscher's universal power law. Enthalpy to dissociate the cation from its original site next to a charge compensating center (Hf) and enthalpy of migration (Hm) have also been estimated. It has been observed that mobility of charge carriers and ac conductivity in case of zinc vanadate glass system increases with increase in Bi2O3 content. In order to determine the conduction mechanism, the ac conductivity and its frequency exponent have been analyzed in the frame work of various theoretical models based on classical hopping over barriers and quantum mechanical tunneling. The ac conduction takes place via tunneling of overlapping large polarons in all the compositions of presently studied vanadate glasses. The fitting of experimental data of ac conductivity with overlapping large polarons tunneling model has also been done. The parameters; density of states at Fermi level (N(EF)), activation energy associated with charge transfer between the overlapping sites (WHO), inverse localization length (α) and polaron radius (rp) obtained from fitting of this model with experimental data are reasonable.

Innovative Strategies for Clinical Microscopy Instruction: Virtual Versus Light Microscopy.

PubMed

McDaniel, M Jane; Russell, Gregory B; Crandall, Sonia J

2018-06-01

The purpose of the study was to compare virtual microscopy with light microscopy to determine differences in learning outcomes and learner attitudes in teaching clinical microscopy to physician assistant (PA) students. A prospective, randomized, crossover design study was conducted with a convenience sample of 67 first-year PA students randomized to 2 groups. One group used light microscopes to find microscopic structures, whereas the other group used instructor-directed video streaming of microscopic elements. At the midpoint of the study, the groups switched instructional strategies. Learning outcomes were assessed via posttest after each section of the study, with comparison of final practical examination results to previous cohorts. Attitudes about the 2 educational strategies were assessed through a postcourse questionnaire with a Likert scale. Analysis of the first posttest demonstrated that students in the video-streamed group had significantly better learning outcomes than those in the light microscopy group (P = .004; Cohen's d = 0.74). Analysis of the posttest after crossover showed no differences between the 2 groups (P = .48). Between the 2 posttests, students first assigned to the light microscopy group scored a 6.6 mean point increase (±10.4 SD; p = .0011), whereas students first assigned to the virtual microscopy group scored a 1.3 mean point increase (±7.1 SD; p = .29). The light microscopy group improved more than the virtual microscopy group (P = .019). Analysis of practical examination data revealed higher scores for the study group compared with 5 previous cohorts of first-year students (P < .0001; Cohen's d = 0.66). Students preferred virtual microscopy to traditional light microscopy. Virtual microscopy is an effective educational strategy, and students prefer this method when learning to interpret images of clinical specimens.

Two Formulations of Venlafaxine are Bioequivalent when Administered as Open Capsule Mixed with Applesauce to Healthy Subjects.

PubMed

Jain, Renu T; Panda, J; Srivastava, A

2011-09-01

Venlafaxine is a unique antidepressant approved for treatment of various depressive disorders. A single dose, cross-over bioequivalence study was performed with two different formulations of venlafaxine 150 mg extended-release capsules in which the contents of capsule were mixed with applesauce and administered to healthy subjects under fed condition. A total of 24 healthy adult male subjects participated in this randomized, single-dose, non-blinded, two-way crossover study conducted at a single centre and 23 subjects completed the study as per the study protocol. After an overnight fast of 10 h, a high-fat and high-calorie breakfast was served 30 min before dosing. The subjects then received a single dose of either formulation administered with apple sauce followed by 240 ml of water as per randomized schedule in each period separated by a washout period of 7 days. A series of blood samples were collected upto 72 h for estimation of venlafaxine and its active metabolite, O-desmethylvenlafaxine. The quantification of venlafaxine and O-desmethylvenlafaxine was done by LC-MS/MS method and pharmacokinetic and statistical analysis by WinNonlin(®) 5.2 and SAS(®) 9.1.3. The results of the study demonstrated bioequivalence of two formulations as the 90% confidence interval for the intra-individual mean ratio of log-transformed C(max), AUC(0-t) and AUC(0-inf) of the test to the reference formulation were found within the defined bioequivalence range of 80.00%-125.00%. Both the formulations were well tolerated. This alternative mode of administration may provide benefits to patients who have difficulty in swallowing the capsule as a whole.

Two Formulations of Venlafaxine are Bioequivalent when Administered as Open Capsule Mixed with Applesauce to Healthy Subjects

PubMed Central

Jain, Renu T.; Panda, J.; Srivastava, A.

2011-01-01

Venlafaxine is a unique antidepressant approved for treatment of various depressive disorders. A single dose, cross-over bioequivalence study was performed with two different formulations of venlafaxine 150 mg extended-release capsules in which the contents of capsule were mixed with applesauce and administered to healthy subjects under fed condition. A total of 24 healthy adult male subjects participated in this randomized, single-dose, non-blinded, two-way crossover study conducted at a single centre and 23 subjects completed the study as per the study protocol. After an overnight fast of 10 h, a high-fat and high-calorie breakfast was served 30 min before dosing. The subjects then received a single dose of either formulation administered with apple sauce followed by 240 ml of water as per randomized schedule in each period separated by a washout period of 7 days. A series of blood samples were collected upto 72 h for estimation of venlafaxine and its active metabolite, O-desmethylvenlafaxine. The quantification of venlafaxine and O-desmethylvenlafaxine was done by LC-MS/MS method and pharmacokinetic and statistical analysis by WinNonlin® 5.2 and SAS® 9.1.3. The results of the study demonstrated bioequivalence of two formulations as the 90% confidence interval for the intra-individual mean ratio of log-transformed Cmax, AUC0-t and AUC0-inf of the test to the reference formulation were found within the defined bioequivalence range of 80.00%-125.00%. Both the formulations were well tolerated. This alternative mode of administration may provide benefits to patients who have difficulty in swallowing the capsule as a whole. PMID:22923863

Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study.

PubMed

Hoang, Thanh D; Olsen, Cara H; Mai, Vinh Q; Clyde, Patrick W; Shakir, Mohamed K M

2013-05-01

Patients previously treated with desiccated thyroid extract (DTE), when being switched to levothyroxine (L-T₄), occasionally did not feel as well despite adequate dosing based on serum TSH levels. Our objective was to investigate the effectiveness of DTE compared with L-T₄ in hypothyroid patients. We conducted a randomized, double-blind, crossover study at a tertiary care center. Patients (n = 70, age 18-65 years) diagnosed with primary hypothyroidism on a stable dose of L-T₄ for 6 months were included in the study. Patients were randomized to either DTE or L-T₄ for 16 weeks and then crossed over for the same duration. Biochemical and neurocognitive tests at baseline and at the end of each treatment period were evaluated. There were no differences in symptoms and neurocognitive measurements between the 2 therapies. Patients lost 3 lb on DTE treatment (172.9 ± 36.4 lb vs 175.7 ± 37.7 lb, P < .001). At the end of the study, 34 patients (48.6%) preferred DTE, 13 (18.6%) preferred L-T₄, and 23 (32.9%) had no preference. In the subgroup analyses, those patients who preferred DTE lost 4 lb during the DTE treatment, and their subjective symptoms were significantly better while taking DTE as measured by the general health questionnaire-12 and thyroid symptom questionnaire (P < .001 for both). Five variables were predictors of preference for DTE. DTE therapy did not result in a significant improvement in quality of life; however, DTE caused modest weight loss and nearly half (48.6%) of the study patients expressed preference for DTE over L-T₄. DTE therapy may be relevant for some hypothyroid patients.

Metabolic and hormonal effects of caffeine: randomized, double-blind, placebo-controlled crossover trial.

PubMed

MacKenzie, Todd; Comi, Richard; Sluss, Patrick; Keisari, Ronit; Manwar, Simone; Kim, Janice; Larson, Robin; Baron, John A

2007-12-01

In short-term studies, caffeine has been shown to increase insulin levels, reduce insulin sensitivity, and increase cortisol levels. However, epidemiological studies have indicated that long-term consumption of beverages containing caffeine such as coffee and green tea is associated with a reduced risk of type 2 diabetes mellitus. There is a paucity of randomized studies addressing the metabolic and hormonal effects of consuming caffeine over periods of more than 1 day. We evaluated the effect of oral intake of 200 mg of caffeine taken twice a day for 7 days on glucose metabolism, as well as on serum cortisol, dehydroepiandrosterone (DHEA), and androstenedione, and on nighttime salivary melatonin. A double-blind, randomized, placebo-controlled crossover study with periods of 7 days and washouts of 5 days comparing caffeine with placebo capsules was conducted. Participants were 16 healthy adults aged 18 to 22 years with a history of caffeine consumption. Blood samples from each subject were assayed for glucose, insulin, serum cortisol, DHEA, and androstenedione on the eighth day of each period after an overnight fast. Nighttime salivary melatonin was also measured. Insulin levels were significantly higher (by 1.80 microU/mL; 95% confidence interval, 0.33-3.28) after caffeine intake than after placebo. The homeostasis model assessment index of insulin sensitivity was reduced by 35% (95% confidence interval, 7%-62%) by caffeine. There were no differences in glucose, DHEA, androstenedione, and melatonin between treatment periods. This study provides evidence that daily caffeine intake reduces insulin sensitivity; the effect persists for at least a week and is evident up to 12 hours after administration.

Short, frequent, 5-days-per-week, in-center hemodialysis versus 3-days-per week treatment: a randomized crossover pilot trial through the Midwest Pediatric Nephrology Consortium.

PubMed

Laskin, Benjamin L; Huang, Guixia; King, Eileen; Geary, Denis F; Licht, Christoph; Metlay, Joshua P; Furth, Susan L; Kimball, Tom; Mitsnefes, Mark

2017-08-01

No controlled trials in children with end-stage kidney disease have assessed the benefits of more frequently administered hemodialysis (HD). We conducted a multicenter, crossover pilot trial to determine if short, more frequent (5 days per week) in-center HD was feasible and associated with improvements in blood pressure compared with three conventional HD treatments per week. Because adult studies have not controlled for the weekly duration of dialysis, we fixed the total treatment time at 12 h a week of dialysis during two 3-month study periods; only frequency varied from 5 to 3 days per week between study periods. Eight children (median age 16.7 years) consented at three children's hospitals. The prespecified primary composite outcome was a sustained 10% decrease in systolic blood pressure and/or a decrease in antihypertensive medications relative to each study period's baseline. Among the six patients completing both study periods, five (83.3%) experienced the primary outcome during HD performed 5 days per week but not 3 days per week; one of the six (16.7%) achieved that outcome during 3-day but not 5-day (p = 0.22) per week HD. During 5-day HD, all patients had significantly more treatments during which their pre-HD systolic (p = 0.01) or diastolic (p = 0.01) blood pressure was 10% lower than baseline. We observed that more frequent HD sessions per week was feasible and associated with improved blood pressure control, but barriers to changing thrice-weekly standard of care include financial reimbursement and the time demands associated with more frequent treatments.

Acute triggers of myocardial infarction: A case-crossover study.

PubMed

Ghiasmand, Maryam; Moghadamnia, Mohammad Taghi; Pourshaikhian, Majid; Kazemnejad Lili, Ehsan

2017-12-01

Acute myocardial infarction (AMI) is one of the most preventable non-communicable diseases in human. Identifying triggers of myocardial infarction (MI) and prevention ways of exposure-induced complications can reduce morbidity and mortality in people at risk. The aim of this study was to identify the emotional, environmental, physical and chemical dimensions of acute triggers in patients with AMI. This case-crossover study was conducted on 269 patients with AMI, hospitalized at two remedial centers in Rasht in 2015. The study samples were selected by convenient sampling method. Data were collected using researcher-made questionnaire through interviews. Hazard and control periods for each trigger and its effects on the development of MI were studied. The collected data were analyzed using descriptive and analytical statistical methods, Cochran test, and generalized estimating equation (GEE) model with logistics function default in SPSS version 21, and p  < 0.05 was considered statistically significant. The results showed that quarrel ( P  = 0.008, OR = 2.01) and hearing the sudden news ( P  = 0.001, OR = 2.19) were the most common emotional triggers. Respiratory infections ( P  = 0.0001, OR = 6.78) and exposure to hot or cold weather ( P  = 0.005, OR = 2.19) were the most frequent environmental triggers. Doing heavy activities ( P  = 0.005, OR = 1.66) and sexual activities ( P  = 0.003, OR = 2.36) were among the most common physical triggers. High-fat foods consumption and overeating ( P  = 0.0001, OR = 3.79) were the most frequent chemical triggers of AMI. It seems that given the importance of the triggers in the incidence of AMI, planning is necessary to train vulnerable individuals to reduce exposure to triggers.

Curcuma decreases serum hepcidin levels in healthy volunteers: a placebo-controlled, randomized, double-blind, cross-over study.

PubMed

Lainé, Fabrice; Laviolle, Bruno; Bardou-Jacquet, Edouard; Fatih, Nadia; Jezequel, Caroline; Collet, Nicolas; Ropert, Martine; Morcet, Jeff; Hamon, Catherine; Reymann, Jean-Michel; Loréal, Olivier

2017-10-01

Hepcidin, secreted by hepatocytes, controls iron metabolism by limiting iron egress in plasma. Hepcidin is upregulated during inflammation through the activation of the signal transducer and activator of transcription 3 (STAT3) transduction pathway, which decreases iron bioavailability and may explain the anemia of chronic inflammatory disease. In vitro, it has been shown that curcumin can decrease hepcidin synthesis by decreasing STAT3 activity. We conducted a proof-of-concept study to assess the effect of curcuma on hepcidin synthesis in human. This was a placebo-controlled, randomized, double-blind, cross-over, two-period study performed in 18 healthy male volunteers. Subjects received a single oral dose of 6 g curcuma containing 2% of curcumin or placebo. Serum hepcidin and iron parameters were assessed repeatedly until 48 h after dosing. When compared with a placebo curcuma decreased hepcidin levels significantly at 6 h (-19%, P = 0.004), 8 h (-17%, P = 0.009), and 12 h (-17%, P = 0.007) and tended to decrease hepcidin at 24 h (-15%, P = 0.076). Curcuma also significantly increased serum ferritin levels at 6 and 8 h (+7% for both times, P = 0.018, 0.030, respectively) and had no effects on serum iron, transferrin, and transferrin saturation. This pilot study showed that curcuma decreases serum hepcidin levels in human and supports the idea that curcuma could be useful in treating hepcidin overproduction during inflammatory processes. Confirmatory studies in patients with chronic inflammation are now required to determine the optimal dose and therapeutic scheme of curcuma. © 2017 Société Française de Pharmacologie et de Thérapeutique.

Patient profiling can identify patients with adult spinal deformity (ASD) at risk for conversion from nonoperative to surgical treatment: initial steps to reduce ineffective ASD management.

PubMed

Passias, Peter G; Jalai, Cyrus M; Line, Breton G; Poorman, Gregory W; Scheer, Justin K; Smith, Justin S; Shaffrey, Christopher I; Burton, Douglas C; Fu, Kai-Ming G; Klineberg, Eric O; Hart, Robert A; Schwab, Frank; Lafage, Virginie; Bess, Shay

2018-02-01

Non-operative management is a common initial treatment for patients with adult spinal deformity (ASD) despite reported superiority of surgery with regard to outcomes. Ineffective medical care is a large source of resource drain on the health system. Characterization of patients with ASD likely to elect for operative treatment from non-operative management may allow for more efficient patient counseling and cost savings. This study aimed to identify deformity and disability characteristics of patients with ASD who ultimately convert to operative treatment compared with those who remain non-operative and those who initially choose surgery. A retrospective review was carried out. A total of 510 patients with ASD (189 non-operative, 321 operative) with minimum 2-year follow-up comprised the patient sample. Oswestry Disability Index (ODI), Short-Form 36 Health Assessment (SF-36), Scoliosis Research Society questionnaire (SRS-22r), and spinopelvic radiographic alignment were the outcome measures. Demographic, radiographic, and patient-reported outcome measures (PROMs) from a cohort of patients with ASD prospectively enrolled into a multicenter database were evaluated. Patients were divided into three treatment cohorts: Non-operative (NON=initial non-operative treatment and remained non-operative), Operative (OP=initial operative treatment), and Crossover (CROSS=initial non-operative treatment with subsequent conversion to operative treatment). NON and OP groups were propensity score-matched (PSM) to CROSS for baseline demographics (age, body mass index, Charlson Comorbidity Index). Time to crossover was divided into early (<1 year) and late (>1 year). Outcome measures were compared across and within treatment groups at four time points (baseline, 6 weeks, 1 year, and 2 years). Following PSM, 118 patients were included (NON=39, OP=38, CROSS=41). Crossover rate was 21.7% (41/189). Mean time to crossover was 394 days. All groups had similar baseline sagittal alignment, but CROSS had larger pelvic incidence and lumbar lordosis (PI-LL) mismatch than NON (11.9° vs. 3.1°, p=.032). CROSS and OP had similar baseline PROM scores; however, CROSS had worse baseline ODI, PCS, SRS-22r (p<.05). At time of crossover, CROSS had worse ODI (35.7 vs. 27.8) and SRS Satisfaction (2.6 vs. 3.3) compared with NON (p<.05). Alignment remained similar for CROSS from baseline to conversion; however, PROMs (ODI, PCS, SRS Activity/Pain/Total) worsened (p<.05). Early and late crossover evaluation demonstrated CROSS-early (n=25) had worsening ODI, SRS Activity/Pain at time of crossover (p<.05). From time of crossover to 2-year follow-up, CROSS-early had less SRS Appearance/Mental improvement compared with OP. Both CROSS-early/late had worse baseline, but greater improvements, in ODI, PCS, SRS Pain/Total compared with NON (p<.05). Baseline alignment and disability parameters increased crossover odds-Non with Schwab T/L/D curves and ODI≥40 (odds ratio [OR]: 3.05, p=.031), and Non with high PI-LL modifier grades ("+"/'++') and ODI≥40 (OR: 5.57, p=.007) were at increased crossover risk. High baseline and increasing disability over time drives conversion from non-operative to operative ASD care. CROSS patients had similar spinal deformity but worse PROMs than NON. CROSS achieved similar 2-year outcome scores as OP. Profiling at first visit for patients at risk of crossover may optimize physician counseling and cost savings. Copyright © 2017. Published by Elsevier Inc.

A Time-Stratified Case-Crossover Study of Ambient Ozone Exposure and Emergency Department Visits for Specific Respiratory Diagnoses in California (2005–2008)

PubMed Central

Malig, Brian J.; Pearson, Dharshani L.; Chang, Yun Brenda; Broadwin, Rachel; Basu, Rupa; Green, Rochelle S.; Ostro, Bart

2015-01-01

Background: Studies have explored ozone’s connection to asthma and total respiratory emergency department visits (EDVs) but have neglected other specific respiratory diagnoses despite hypotheses relating ozone to respiratory infections and allergic responses. Objective: We examined relationships between ozone and EDVs for respiratory visits, including specifically acute respiratory infections (ARI), asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and upper respiratory tract inflammation (URTI). Methods: We conducted a multi-site time-stratified case-crossover study of ozone exposures for approximately 3.7 million respiratory EDVs from 2005 through 2008 among California residents living within 20 km of an ozone monitor. Conditional logistic regression was used to estimate associations by climate zone. Random effects meta-analysis was then applied to estimate pooled excess risks (ER). Effect modification by season, distance from the monitor and individual demographic characteristics (i.e., age, race/ethnicity, sex, and payment method), and confounding by other gaseous air pollutants were also investigated. Meta-regression was utilized to explore how climate zone–level meteorological, demographic, and regional differences influenced estimates. Results: We observed ozone-associated increases in all respiratory, asthma, and ARI visits, which were slightly larger in the warm season [asthma ER per 10-ppb increase in mean of same and previous 3 days ozone exposure (lag03) = 2.7%, 95% CI: 1.5, 3.9; ARI ERlag03 = 1.4%, 95% CI: 0.8, 1.9]. EDVs for pneumonia, COPD, and URTI were also significantly associated with ozone exposure over the whole year, but typically more consistently so during the warm season. Conclusions: Short-term ozone exposures among California residents living near an ozone monitor were positively associated with EDVs for asthma, ARI, pneumonia, COPD, and URTI from 2005 through 2008. Those associations were typically larger and more consistent during the warm season. Our findings suggest that these outcomes should be considered when evaluating the potential health benefits of reducing ozone concentrations. Citation: Malig BJ, Pearson DL, Chang YB, Broadwin R, Basu R, Green RS, Ostro B. 2016. A time-stratified case-crossover study of ambient ozone exposure and emergency department visits for specific respiratory diagnoses in California (2005–2008). Environ Health Perspect 124:745–753; http://dx.doi.org/10.1289/ehp.1409495 PMID:26647366

Magnetic-field-temperature phase diagram of alternating ferrimagnetic chains: Spin-wave theory from a fully polarized vacuum

NASA Astrophysics Data System (ADS)

da Silva, W. M.; Montenegro-Filho, R. R.

2017-12-01

Quantum critical (QC) phenomena can be accessed by studying quantum magnets under an applied magnetic field (B ). The QC points are located at the end points of magnetization plateaus and separate gapped and gapless phases. In one dimension, the low-energy excitations of the gapless phase form a Luttinger liquid (LL), and crossover lines bound insulating (plateau) and LL regimes, as well as the QC regime. Alternating ferrimagnetic chains have a spontaneous magnetization at T =0 and gapped excitations at zero field. Besides the plateau at the fully polarized (FP) magnetization, due to the gap there is another magnetization plateau at the ferrimagnetic (FRI) magnetization. We develop spin-wave theories to study the thermal properties of these chains under an applied magnetic field: one from the FRI classical state and another from the FP state, comparing their results with quantum Monte Carlo data. We deepen the theory from the FP state, obtaining the crossover lines in the T vs B low-T phase diagram. In particular, from local extreme points in the susceptibility and magnetization curves, we identify the crossover between an LL regime formed by excitations from the FRI state to another built from excitations of the FP state. These two LL regimes are bounded by an asymmetric domelike crossover line, as observed in the phase diagram of other quantum magnets under an applied magnetic field.

Study of. lambda. parameters and crossover phenomena in SU(N) x SU(N) sigma models in two dimensions

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

Shigemitsu, J; Kogut, J B

1981-01-01

The spin system analogues of recent studies of the string tension and ..lambda.. parameters of SU(N) gauge theories in 4 dimensions are carried out for the SU(N) x SU(N) and O(N) models in 2 dimensions. The relations between the ..lambda.. parameters of both the Euclidean and Hamiltonian formulation of the lattice models and the ..lambda.. parameter of the continuum models are obtained. The one loop finite renormalization of the speed of light in the lattice Hamiltonian formulations of the O(N) and SU(N) x SU(N) models is calculated. Strong coupling calculations of the mass gaps of these spin models are donemore » for all N and the constants of proportionality between the gap and the ..lambda.. parameter of the continuum models are obtained. These results are contrasted with similar calculations for the SU(N) gauge models in 3+1 dimensions. Identifying suitable coupling constants for discussing the N ..-->.. infinity limits, the numerical results suggest that the crossover from weak to strong coupling in the lattice O(N) models becomes less abrupt as N increases while the crossover for the SU(N) x SU(N) models becomes more abrupt. The crossover in SU(N) gauge theories also becomes more abrupt with increasing N, however, at an even greater rate than in the SU(N) x SU(N) spin models.« less

Two measures of bilingualism in the memories of immigrants and indigenous minorities: crossover memories and codeswitching.

PubMed

Altman, Carmit

2015-04-01

Two indices of bilingualism, crossover memories and codeswitching (CS), were explored in five groups of immigrant (English-Hebrew, Georgian-Hebrew Russian-Hebrew) and indigenous bilinguals (Arabic-Hebrew, Hebrew-English). Participants recalled memories in response to cue words and then were asked to report the language of retrieval and provide a more elaborate narrative. More memories were 'same language' memories, recalled in the language of the experimental session/cue word, but as many as 48 % of the memories were crossovers, i.e. memories reported in a language other than the language of the session/cue word. In an effort to examine the ecological validity of the self-reported language of the memories, the frequency of CS in the elaborated narratives was investigated. For the entire sample, more CS was found for self-reported crossover memories in L2 sessions. In a further analysis of CS in crossover memories, collapsed across L1 and L2 sessions, significant differences emerged between immigrants and indigenous bilinguals. Differences between immigrant and non-immigrant bilinguals are discussed in terms of the role of activation in crossover memories.

Interference-mediated synaptonemal complex formation with embedded crossover designation

PubMed Central

Zhang, Liangran; Espagne, Eric; de Muyt, Arnaud; Zickler, Denise; Kleckner, Nancy E.

2014-01-01

Biological systems exhibit complex patterns at length scales ranging from the molecular to the organismic. Along chromosomes, events often occur stochastically at different positions in different nuclei but nonetheless tend to be relatively evenly spaced. Examples include replication origin firings, formation of chromatin loops along chromosome axes and, during meiosis, localization of crossover recombination sites (“crossover interference”). We present evidence in the fungus Sordaria macrospora that crossover interference is part of a broader pattern that includes synaptonemal complex (SC) nucleation. This pattern comprises relatively evenly spaced SC nucleation sites, among which a subset are crossover sites that show a classical interference distribution. This pattern ensures that SC forms regularly along the entire length of the chromosome as required for the maintenance of homolog pairing while concomitantly having crossover interactions locally embedded within the SC structure as required for both DNA recombination and structural events of chiasma formation. This pattern can be explained by a threshold-based designation and spreading interference process. This model can be generalized to give diverse types of related and/or partially overlapping patterns, in two or more dimensions, for any type of object. PMID:25380597

Statistical power analysis of cardiovascular safety pharmacology studies in conscious rats.

PubMed

Bhatt, Siddhartha; Li, Dingzhou; Flynn, Declan; Wisialowski, Todd; Hemkens, Michelle; Steidl-Nichols, Jill

2016-01-01

Cardiovascular (CV) toxicity and related attrition are a major challenge for novel therapeutic entities and identifying CV liability early is critical for effective derisking. CV safety pharmacology studies in rats are a valuable tool for early investigation of CV risk. Thorough understanding of data analysis techniques and statistical power of these studies is currently lacking and is imperative for enabling sound decision-making. Data from 24 crossover and 12 parallel design CV telemetry rat studies were used for statistical power calculations. Average values of telemetry parameters (heart rate, blood pressure, body temperature, and activity) were logged every 60s (from 1h predose to 24h post-dose) and reduced to 15min mean values. These data were subsequently binned into super intervals for statistical analysis. A repeated measure analysis of variance was used for statistical analysis of crossover studies and a repeated measure analysis of covariance was used for parallel studies. Statistical power analysis was performed to generate power curves and establish relationships between detectable CV (blood pressure and heart rate) changes and statistical power. Additionally, data from a crossover CV study with phentolamine at 4, 20 and 100mg/kg are reported as a representative example of data analysis methods. Phentolamine produced a CV profile characteristic of alpha adrenergic receptor antagonism, evidenced by a dose-dependent decrease in blood pressure and reflex tachycardia. Detectable blood pressure changes at 80% statistical power for crossover studies (n=8) were 4-5mmHg. For parallel studies (n=8), detectable changes at 80% power were 6-7mmHg. Detectable heart rate changes for both study designs were 20-22bpm. Based on our results, the conscious rat CV model is a sensitive tool to detect and mitigate CV risk in early safety studies. Furthermore, these results will enable informed selection of appropriate models and study design for early stage CV studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Magnetic field tuning of an excitonic insulator between the weak and strong coupling regimes in quantum limit graphite [Tunable excitonic insulator in quantum limit graphite

DOE PAGES

Zhu, Zengwei; McDonald, R. D.; Shekhter, A.; ...

2017-05-04

Here, the excitonic insulator phase has long been predicted to form in proximity to a band gap opening in the underlying band structure. The character of the pairing is conjectured to crossover from weak (BCS-like) to strong coupling (BEC-like) as the underlying band structure is tuned from the metallic to the insulating side of the gap opening. Here we report the high-magnetic field phase diagram of graphite to exhibit just such a crossover. By way of comprehensive angle-resolved magnetoresistance measurements, we demonstrate that the underlying band gap opening occurs inside the magnetic field-induced phase, paving the way for a systematicmore » study of the BCS-BEC-like crossover by means of conventional condensed matter probes.« less

Compressed exponential relaxation in liquid silicon: Universal feature of the crossover from ballistic to diffusive behavior in single-particle dynamics

NASA Astrophysics Data System (ADS)

Morishita, Tetsuya

2012-07-01

We report a first-principles molecular-dynamics study of the relaxation dynamics in liquid silicon (l-Si) over a wide temperature range (1000-2200 K). We find that the intermediate scattering function for l-Si exhibits a compressed exponential decay above 1200 K including the supercooled regime, which is in stark contrast to that for normal "dense" liquids which typically show stretched exponential decay in the supercooled regime. The coexistence of particles having ballistic-like motion and those having diffusive-like motion is demonstrated, which accounts for the compressed exponential decay in l-Si. An attempt to elucidate the crossover from the ballistic to the diffusive regime in the "time-dependent" diffusion coefficient is made and the temperature-independent universal feature of the crossover is disclosed.

Inequity in work and intimate relationships: a Spillover-Crossover model.

PubMed

Bakker, Arnold B; Petrou, Paraskevas; Tsaousis, Ioannis

2012-01-01

This study among 267 Greek teachers and their partners tested and expanded the recently proposed Spillover-Crossover model (SCM) of well-being. Accordingly, experiences built up at work spill over to the home domain, and then influence the partner. The authors integrated equity theory in the model by formulating hypotheses about exchange in interpersonal relationships. Structural equation modeling analyses supported the spillover hypothesis that teachers who lose their work engagement as a result of an inequitable relationship with their students invest less in the relationship with their partner. In addition, the results supported the crossover hypothesis that teachers' relationship investments, in turn, show a negative relationship with inequity in the intimate relationship as perceived by the partner; and inequity in the intimate relationship contributed to partner depression. The findings are discussed in light of the SCM of well-being.

Magnetic field tuning of an excitonic insulator between the weak and strong coupling regimes in quantum limit graphite [Tunable excitonic insulator in quantum limit graphite

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

Zhu, Zengwei; McDonald, R. D.; Shekhter, A.

Here, the excitonic insulator phase has long been predicted to form in proximity to a band gap opening in the underlying band structure. The character of the pairing is conjectured to crossover from weak (BCS-like) to strong coupling (BEC-like) as the underlying band structure is tuned from the metallic to the insulating side of the gap opening. Here we report the high-magnetic field phase diagram of graphite to exhibit just such a crossover. By way of comprehensive angle-resolved magnetoresistance measurements, we demonstrate that the underlying band gap opening occurs inside the magnetic field-induced phase, paving the way for a systematicmore » study of the BCS-BEC-like crossover by means of conventional condensed matter probes.« less

Thermal conductance of suspended nanoribbons: interplay between strain and interatomic potential nonlinearity

NASA Astrophysics Data System (ADS)

Barreto, Roberto; Florencia Carusela, M.; Monastra, Alejandro G.

2017-10-01

We investigate the role that nonlinearity in the interatomic potential has on the thermal conductance of a suspended nanoribbon when it is subjected to a longitudinal strain. To focus on the first cubic and quartic nonlinear terms of a general potential, we propose an atomic system based on an α-β Fermi-Pasta-Ulam nearest neighbor interaction. We perform classical molecular dynamics simulations to investigate the contribution of longitudinal, transversal and flexural modes to the thermal conductance as a function of the α-β parameters and the applied strain. We compare the cases where atoms are allowed to vibrate only in plane (2D) with the case of vibrations in and out of plane (3D). We find that the dependence of conductance on α and β relies on a crossover phenomenon between linear/nonlinear delocalized/localized flexural and transversal modes, driven by an on/off switch of the strain.

Effective cross-over to granisetron after failure to ondansetron, a randomized double blind study in patients failing ondansetron plus dexamethasone during the first 24 hours following highly emetogenic chemotherapy

PubMed Central

de Wit, R; de Boer, A C; vd Linden, G H M; Stoter, G; Sparreboom, A; Verweij, J

2001-01-01

In view of the similarity in chemical structure of the available 5HT3-receptor antagonists it is assumed, whilst these agents all act at the same receptor, that failure to one agent would predict subsequent failure to all 5HT3-receptor antagonists. We conducted a randomized double blind trial of granisetron 3 mg plus dexamethasone 10 mg versus continued treatment with ondansetron 8 mg plus dexamethasone 10 mg in patients with protection failure on ondansetron 8 mg plus dexamethasone 10 mg during the first 24 hours following highly emetogenic chemotherapy. Of 40 eligible patients, 21 received ondansetron + dexamethasone and 19 received granisetron + dexamethasone. We found a significant benefit from crossing-over to granisetron after failure on ondansetron. Of the 19 patients who crossed over to granisetron, 9 patients obtained complete protection, whereas this was observed in 1 of the 21 patients continuing ondansetron, P = 0.005. These results indicate that there is no complete cross-resistance between 5HT3-receptor antagonists, and that patients who have acute protection failure on one 5HT3-receptor antagonist should be offered cross-over to another 5HT3-receptor antagonist. © 2001 Cancer Research Campaign  http://www.bjcancer.com PMID:11710819

Cranberry (poly)phenol metabolites correlate with improvements in vascular function: A double-blind, randomized, controlled, dose-response, crossover study.

PubMed

Rodriguez-Mateos, Ana; Feliciano, Rodrigo P; Boeres, Albert; Weber, Timon; Dos Santos, Claudia Nunes; Ventura, M Rita; Heiss, Christian

2016-10-01

Cranberries are rich in potentially bioactive (poly)phenols. The aim of this paper was to investigate whether cranberry juice intake can improve vascular function in healthy men in a dose- and time-dependent manner, and to understand which of the circulating (poly)phenol metabolites correlate with vascular effects. A double-blind randomized controlled crossover trial was conducted in ten healthy males. Flow-mediated dilation (FMD), blood pressure, pulse wave velocity and augmentation index were investigated at baseline, 1, 2, 4, 6, and 8 h post-consumption of cranberry juices containing 409, 787, 1238, 1534, and 1910 mg of total cranberry (poly)phenols (TP), and a control drink. Plasma (poly)phenol metabolites were analyzed by UPLC-Q-TOF MS using authentic standards. We observed dose-dependent increases in FMD at 1, 2, 4, 6, and 8 h with a peak at 4 h and maximal effects with juice containing 1238 mg TP. A total of 60 metabolites were quantified in plasma after cranberry consumption. Twelve (poly)phenol metabolites significantly correlated with the increases in FMD, including ferulic and caffeic acid sulfates, quercetin-3-O-ß-D-glucuronide and a γ-valerolactone sulfate. (Poly)phenols in cranberry juice can improve vascular function in healthy males and this is linked to the presence of specific newly identified plasma metabolites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Homing by path integration when a locomotion trajectory crosses itself.

PubMed

Yamamoto, Naohide; Meléndez, Jayleen A; Menzies, Derek T

2014-01-01

Path integration is a process with which navigators derive their current position and orientation by integrating self-motion signals along a locomotion trajectory. It has been suggested that path integration becomes disproportionately erroneous when the trajectory crosses itself. However, there is a possibility that this previous finding was confounded by effects of the length of a traveled path and the amount of turns experienced along the path, two factors that are known to affect path integration performance. The present study was designed to investigate whether the crossover of a locomotion trajectory truly increases errors of path integration. In an experiment, blindfolded human navigators were guided along four paths that varied in their lengths and turns, and attempted to walk directly back to the beginning of the paths. Only one of the four paths contained a crossover. Results showed that errors yielded from the path containing the crossover were not always larger than those observed in other paths, and the errors were attributed solely to the effects of longer path lengths or greater degrees of turns. These results demonstrated that path crossover does not always cause significant disruption in path integration processes. Implications of the present findings for models of path integration are discussed.

Test equality in binary data for a 4 × 4 crossover trial under a Latin-square design.

PubMed

Lui, Kung-Jong; Chang, Kuang-Chao

2016-10-15

When there are four or more treatments under comparison, the use of a crossover design with a complete set of treatment-receipt sequences in binary data is of limited use because of too many treatment-receipt sequences. Thus, we may consider use of a 4 × 4 Latin square to reduce the number of treatment-receipt sequences when comparing three experimental treatments with a control treatment. Under a distribution-free random effects logistic regression model, we develop simple procedures for testing non-equality between any of the three experimental treatments and the control treatment in a crossover trial with dichotomous responses. We further derive interval estimators in closed forms for the relative effect between treatments. To evaluate the performance of these test procedures and interval estimators, we employ Monte Carlo simulation. We use the data taken from a crossover trial using a 4 × 4 Latin-square design for studying four-treatments to illustrate the use of test procedures and interval estimators developed here. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Pressure and Temperature Sensors Using Two Spin Crossover Materials.

PubMed

Jureschi, Catalin-Maricel; Linares, Jorge; Boulmaali, Ayoub; Dahoo, Pierre Richard; Rotaru, Aurelian; Garcia, Yann

2016-02-02

The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices.

Ab Initio Calculations of Transport Properties of Vanadium Oxides

NASA Astrophysics Data System (ADS)

Lamsal, Chiranjivi; Ravindra, N. M.

2018-04-01

The temperature-dependent transport properties of vanadium oxides have been studied near the Fermi energy using the Kohn-Sham band structure approach combined with Boltzmann transport equations. V2O5 exhibits significant thermoelectric properties, which can be attributed to its layered structure and stability. Highly anisotropic electrical conduction in V2O5 is clearly manifested in the calculations. Due to specific details of the band structure and anisotropic electron-phonon interactions, maxima and crossovers are also seen in the temperature-dependent Seebeck coefficient of V2O5. During the phase transition of VO2, the Seebeck coefficient changes by 18.9 µV/K, which is close to (within 10% of) the observed discontinuity of 17.3 µV/K.

Aspects of electron transport in zigzag graphene nanoribbons

NASA Astrophysics Data System (ADS)

Bhalla, Pankaj; Pratap, Surender

2018-05-01

In this paper, we investigate the aspects of electron transport in the zigzag graphene nanoribbons (ZGNRs) using the nonequilibrium Green’s function (NEGF) formalism. The latter is an esoteric tool in mesoscopic physics. It is used to perform an analysis of ZGNRs by considering potential well. Within this potential, the dependence of transmission coefficient, local density of states (LDOS) and electron transport properties on number of atoms per unit cell is discussed. It is observed that there is an increment in electron and thermal conductance with increasing number of atoms. In addition to these properties, the dependence of same is also studied in figure of merit. The results infer that the contribution of electrons to enhance the figure of merit is important above the crossover temperature.

Impact of antimicrobial wipes compared with hypochlorite solution on environmental surface contamination in a health care setting: A double-crossover study.

PubMed

Siani, Harsha; Wesgate, Rebecca; Maillard, Jean-Yves

2018-05-11

Antimicrobial wipes are increasingly used in health care settings. This study evaluates, in a clinical setting, the efficacy of sporicidal wipes versus a cloth soaked in a 1,000 ppm chlorine solution. A double-crossover study was performed on 2 different surgical and cardiovascular wards in a 1,000-bed teaching hospital over 29 weeks. The intervention period that consisted of surface decontamination with the preimpregnated wipe or cloth soaked in chlorine followed a 5-week baseline assessment of microbial bioburden on surfaces. Environmental samples from 11 surfaces were analyzed weekly for their microbial content. A total of 1,566 environmental samples and 1,591 ATP swabs were analyzed during the trial. Overall, there were significant differences in the recovery of total aerobic bacteria (P < .001), total anaerobic bacteria (P < .001), and ATP measurement (P < .001) between wards and between the different parts of the crossover study. Generally, the use of wipes produced the largest reduction in the total aerobic and anaerobic counts when compared with the baseline data or the use of 1,000 ppm chlorine. Collectively, the introduction of training plus daily wipe disinfection significantly reduced multidrug-resistant organisms recovered from surfaces. Reversion to using 1,000 ppm chlorine resulted in the number of sites positive for multidrug-resistant organisms rising again. This double-crossover study is the first controlled field trial comparison of using preimpregnated wipes versus cotton cloth dipped into a bucket of hypochlorite to decrease surface microbial bioburden. The results demonstrate the superiority of the preimpregnated wipes in significantly decreasing microbial bioburden from high-touch surfaces. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Melatonin improves sleep in children with epilepsy: randomized, double-blind cross-over study

PubMed Central

Jain, Sejal V; Horn, Paul S; Simakajornboon, Narong; Beebe, Dean W; Holland, Katherine; Byars, Anna W; Glauser, Tracy A

2015-01-01

Objective Insomnia, especially maintenance insomnia is widely prevalent in epilepsy. Although melatonin is commonly used, limited data address its efficacy. We performed a randomized, double-blind, placebo-controlled, cross-over study to identify the effects of melatonin on sleep and seizure control in children with epilepsy. Methods Eleven pre-pubertal, developmentally normal children aged 6–11 years with epilepsy were randomized by software algorithm to receive placebo or 9 mg sustained release melatonin for 4 weeks, followed by a 1-week washout and 4-week crossover condition. The pharmacy performed blinding; patients, parents and study staff other than a statistician were blinded. Primary outcomes were sleep onset latency and wakefulness after sleep onset (WASO) measured on polysomnography. Secondary outcomes included seizure frequency, epileptiform spike density per hour of sleep on EEG and reaction time measures on psychomotor vigilance task. Statistical tests appropriate for cross-over designs were used for analysis. Results Data were analyzed from ten subjects who completed the study. Melatonin decreased sleep latency (Mean difference (MD): 11.4 min, p= 0.02) and WASO (MD 22 min, p=0.04) as compared to placebo. No worsening of spike density or seizure frequency was seen. Additionally, Slow-wave sleep duration and REM latency were increased with melatonin and REM sleep duration was decreased. These changes were statistically significant. Worsening of headache was noted in one subject with migraine on melatonin. Conclusion Sustained-release melatonin resulted in statistically significant decreases in sleep latency and WASO. No clear effects on seizures were observed but the study was too small to allow any conclusions to be drawn in this regard. PMID:25862116

RELIABILITY AND VALIDITY OF FUNCTIONAL PERFORMANCE TESTS IN DANCERS WITH HIP DYSFUNCTION

PubMed Central

Carcia, Christopher R.; Clemente, F. Richard; Phelps, Amy L.; Martin, RobRoy L.

2013-01-01

Study Design: Quasi-experimental, repeated measures. Purpose/Background: Functional performance tests that identify hip joint impairments and assess the effect of intervention have not been adequately described for dancers. The purpose of this study was to examine the reliability and validity of hop and balance tests among a group of dancers with musculoskeletal pain in the hip region. Methods: Nineteen female dancers (age: 18.90±1.11 years; height: 164.85±6.95 cm; weight: 60.37±8.29 kg) with unilateral hip pain were assessed utilizing the cross-over reach, medial triple hop, lateral triple hop, and cross-over hop tests on two occasions, 2 days apart. Test-retest reliability and comparisons between the involved and uninvolved side for each respective test were determined. Results: Intra-class correlation coefficients for the functional performance tests ranged from 0.89-0.96. The cross-over reach test had a SEM of 2.79 cm and a MDC of 7.73 cm. The medial and lateral triple hop tests had SEM values of 7.51 cm and 8.17 cm, and MDC values of 20.81 cm and 22.62 cm, respectively. The SEM was 0.15 seconds and the MDC was 0.42 seconds for the cross-over hop test. Performance on the medial triple hop test was significantly less on the involved side (370.21±38.26 cm) compared to the uninvolved side (388.05±41.49 cm); t(18) = −4.33, p<0.01. The side-to-side comparisons of the cross-over reach test (involved mean=61.68±10.9 cm; uninvolved mean=61.69±8.63 cm); t(18) = −0.004, p=0.99, lateral triple hop test (involved mean=306.92±35.79 cm; uninvolved mean=310.68±24.49 cm); t(18) = −0.55, p=0.59, and cross-over hop test (involved mean=2.49±0.34 seconds; uninvolved mean= 2.61±0.42 seconds; t(18) = −1.84, p=0.08) were not statistically different between sides. Conclusion: The functional performance tests used in this study can be reliably performed on dancers with unilateral hip pain. The medial triple hop test was the only functional performance test with evidence of validity in side-to-side comparisons. These results suggest that the medial triple hop test may be a reliable and valid functional performance test to assess impairments related to hip pain among dancers. Level of Evidence: 3b. Non-consecutive cohort study PMID:24175123

Treatment of pruritus with topically applied opiate receptor antagonist.

PubMed

Bigliardi, Paul L; Stammer, Holger; Jost, Gerhard; Rufli, Theo; Büchner, Stanislaw; Bigliardi-Qi, Mei

2007-06-01

Pruritus is the most common and distressing skin symptom, and treatment of itch is a problem for thousands of people. The currently available therapies are not very effective. Therefore there is an urgent need to find new effective topical drugs against itching. We conducted two separate studies to evaluate the efficacy of topically applied naltrexone, an opioid receptor antagonist, in the treatment of severe pruritus. The objective of the first open study was to correlate the clinical efficacy of topically applied naltrexone in different pruritic skin disorders to a change of epidermal mu-opiate receptor (MOR) expression. The second study was a double-blind, placebo-controlled, crossover study on pruritus in atopic dermatitis. Initially we performed an open pilot study on 18 patients with different chronic pruritic disorders using a topical formulation of 1% naltrexone for 2 weeks. A punch biopsy was performed in 11 patients before and after the application of the naltrexone cream and the staining of epidermal MOR was measured. Subsequently, a randomized, placebo-controlled, crossover trial was performed with the same formulation. We included in this trial 40 patients with localized and generalized atopic dermatitis with severe pruritus. In the open study more than 70% of the patients using the 1% naltrexone cream experienced a significant reduction of pruritus. More interestingly, the topical treatment with naltrexone caused an increase of epidermal MOR staining. The regulation of the epidermal opioid receptor correlated with the clinical assessment. The placebo-controlled, crossover trial demonstrated clearly that the cream containing naltrexone had an overall 29.4% better effect compared with placebo. The formulation containing naltrexone required a median of 46 minutes to reduce the itch symptoms to 50%; the placebo, 74 minutes. We could only take biopsy specimens in 11 patients, which means that a satisfactory statistical analysis of the changes of epidermal MOR staining was not possible. In addition, there was an insufficient number of patients with nephrogenic pruritus and pruritic psoriasis to draw definitive conclusions. The placebo-controlled study showed a significant advantage of topically applied naltrexone over the placebo formulation. This finding is supported by the biopsy results from the open studies, showing a regulation of MOR expression in epidermis after treatment with topical naltrexone, especially in atopic dermatitis. These results clearly show potential for topically applied opioid receptor antagonist in the treatment of pruritus. The placebo formulation also had some antipruritic effects. This underlines the importance of rehydration therapy for dry skin in the treatment of pruritus.

Effect of Stimulative and Sedative Music Videos on Depressive Symptoms and Physiological Relaxation in Older Adults: A Pilot Study.

PubMed

Huang, Chiung-Yu; Hsieh, Yuan-Mei; Lai, Hui-Ling

2016-09-01

Music has been found to improve depressive symptoms and relaxation. However, few studies related to this issue have been conducted using music videos (MVs). The aim was to compare the effects of stimulative and sedative MVs on depressive symptoms and physiological relaxation (i.e., electromyography, heart rate variability, and skin conductance) in older adults with depressive symptoms. Using a 2-week crossover design, interventions alternated between watching a stimulative and sedative MV and vice versa. Each intervention lasted for 30 minutes on 1 day during the first week, and was then alternated to another intervention for 1 day during the following week. Stimulative MVs were more effective in treating depressive symptoms than sedative MVs. Stimulative and sedative MVs had beneficial effects on depressive symptoms and physiological relaxation compared with baseline data. These findings add new knowledge to the literature for health care providers to improve psychophysiological health in older adults with depressive symptoms. [Res Gerontol Nurs. 2016; 9(5):233-242.]. Copyright 2016, SLACK Incorporated.

Scattering and transport statistics at the metal-insulator transition: A numerical study of the power-law banded random-matrix model

NASA Astrophysics Data System (ADS)

Méndez-Bermúdez, J. A.; Gopar, Victor A.; Varga, Imre

2010-09-01

We study numerically scattering and transport statistical properties of the one-dimensional Anderson model at the metal-insulator transition described by the power-law banded random matrix (PBRM) model at criticality. Within a scattering approach to electronic transport, we concentrate on the case of a small number of single-channel attached leads. We observe a smooth crossover from localized to delocalized behavior in the average-scattering matrix elements, the conductance probability distribution, the variance of the conductance, and the shot noise power by varying b (the effective bandwidth of the PBRM model) from small (b≪1) to large (b>1) values. We contrast our results with analytic random matrix theory predictions which are expected to be recovered in the limit b→∞ . We also compare our results for the PBRM model with those for the three-dimensional (3D) Anderson model at criticality, finding that the PBRM model with bɛ[0.2,0.4] reproduces well the scattering and transport properties of the 3D Anderson model.

Neurobehavioral toxicity of cadmium sulfate to the planarian Dugesia dorotocephala

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

Grebe, E.; Schaeffer, D.J.

1991-05-01

The authors are developing bioassays which use planarians (free-living platyhelminthes) for the rapid determination of various types of toxicity, including acute mortality, tumorigenicity, and short-term neurobehavioral responses. Their motivation for using these animals is due to their importance as components of the aquatic ecology of unpolluted streams their sensitivity to low concentrations of environmental toxicants and the presence of a sensitive neurological system with a true brain which allows for complex social behavior. A previous paper described the results of a neurobehavioral bioassay using phenol in a crossover study. This paper reports a similar crossover study using cadmium sulfate.

Association of daily asthma emergency department visits and hospital admissions with ambient air pollutants among the pediatric Medicaid population in Detroit: time-series and time-stratified case-crossover analyses with threshold effects.

PubMed

Li, Shi; Batterman, Stuart; Wasilevich, Elizabeth; Wahl, Robert; Wirth, Julie; Su, Feng-Chiao; Mukherjee, Bhramar

2011-11-01

Asthma morbidity has been associated with ambient air pollutants in time-series and case-crossover studies. In such study designs, threshold effects of air pollutants on asthma outcomes have been relatively unexplored, which are of potential interest for exploring concentration-response relationships. This study analyzes daily data on the asthma morbidity experienced by the pediatric Medicaid population (ages 2-18 years) of Detroit, Michigan and concentrations of pollutants fine particles (PM2.5), CO, NO2 and SO2 for the 2004-2006 period, using both time-series and case-crossover designs. We use a simple, testable and readily implementable profile likelihood-based approach to estimate threshold parameters in both designs. Evidence of significant increases in daily acute asthma events was found for SO2 and PM2.5, and a significant threshold effect was estimated for PM2.5 at 13 and 11 μg m(-3) using generalized additive models and conditional logistic regression models, respectively. Stronger effect sizes above the threshold were typically noted compared to standard linear relationship, e.g., in the time series analysis, an interquartile range increase (9.2 μg m(-3)) in PM2.5 (5-day-moving average) had a risk ratio of 1.030 (95% CI: 1.001, 1.061) in the generalized additive models, and 1.066 (95% CI: 1.031, 1.102) in the threshold generalized additive models. The corresponding estimates for the case-crossover design were 1.039 (95% CI: 1.013, 1.066) in the conditional logistic regression, and 1.054 (95% CI: 1.023, 1.086) in the threshold conditional logistic regression. This study indicates that the associations of SO2 and PM2.5 concentrations with asthma emergency department visits and hospitalizations, as well as the estimated PM2.5 threshold were fairly consistent across time-series and case-crossover analyses, and suggests that effect estimates based on linear models (without thresholds) may underestimate the true risk. Copyright © 2011 Elsevier Inc. All rights reserved.

Statistical analysis of Turbine Engine Diagnostic (TED) field test data

NASA Astrophysics Data System (ADS)

Taylor, Malcolm S.; Monyak, John T.

1994-11-01

During the summer of 1993, a field test of turbine engine diagnostic (TED) software, developed jointly by U.S. Army Research Laboratory and the U.S. Army Ordnance Center and School, was conducted at Fort Stuart, GA. The data were collected in conformance with a cross-over design, some of whose considerations are detailed. The initial analysis of the field test data was exploratory, followed by a more formal investigation. Technical aspects of the data analysis insights that were elicited are reported.

Fluctuation conductance and the Berezinskii-Kosterlitz-Thouless transition in two dimensional epitaxial NbTiN ultra-thin films

NASA Astrophysics Data System (ADS)

K, Makise; H, Terai; T, Yamashita; S, Miki; Z, Wang; Uzawa Y, Y.; S, Ezaki; T, Odou; B, Shinozaki

2012-12-01

We study on the electric transport properties of epitaxial NbTiN ultrathin films in a range from 2 to 8nm. The films with 4 nm thick shows superconductivity of which mean-field superconducting transition temperature is TC0 = 9.43 K The excess conductance due to superconducting fluctuations was measured at temperatures above TC0. The paraconductivity shows a two-dimensional like behaviour at close to TC0. Experimental results are in good agreement with the sum of Aslamazov - Larkin and Maki - Thompson term for superconducting fluctuation theory. Decreasing temperature below TC0, the current-voltage characteristic shows a crossover from linear to nonlinear behaviour. The exponent α of current-voltage relation, V ~ Iα showed universal jump at TCBKT = 9.33 K As results, we find that there is a consistency between the parametrization of the2D characteristics of fluctuation paraconductivity above TC0 and Berezinskii-Kosterlitz-Thouless type behaviour below TC0.

Detection of crossover time scales in multifractal detrended fluctuation analysis

NASA Astrophysics Data System (ADS)

Ge, Erjia; Leung, Yee

2013-04-01

Fractal is employed in this paper as a scale-based method for the identification of the scaling behavior of time series. Many spatial and temporal processes exhibiting complex multi(mono)-scaling behaviors are fractals. One of the important concepts in fractals is crossover time scale(s) that separates distinct regimes having different fractal scaling behaviors. A common method is multifractal detrended fluctuation analysis (MF-DFA). The detection of crossover time scale(s) is, however, relatively subjective since it has been made without rigorous statistical procedures and has generally been determined by eye balling or subjective observation. Crossover time scales such determined may be spurious and problematic. It may not reflect the genuine underlying scaling behavior of a time series. The purpose of this paper is to propose a statistical procedure to model complex fractal scaling behaviors and reliably identify the crossover time scales under MF-DFA. The scaling-identification regression model, grounded on a solid statistical foundation, is first proposed to describe multi-scaling behaviors of fractals. Through the regression analysis and statistical inference, we can (1) identify the crossover time scales that cannot be detected by eye-balling observation, (2) determine the number and locations of the genuine crossover time scales, (3) give confidence intervals for the crossover time scales, and (4) establish the statistically significant regression model depicting the underlying scaling behavior of a time series. To substantive our argument, the regression model is applied to analyze the multi-scaling behaviors of avian-influenza outbreaks, water consumption, daily mean temperature, and rainfall of Hong Kong. Through the proposed model, we can have a deeper understanding of fractals in general and a statistical approach to identify multi-scaling behavior under MF-DFA in particular.

The ASPIRE study: design and methods of an in-clinic crossover trial on the efficacy of automatic insulin pump suspension in exercise-induced hypoglycemia.

PubMed

Brazg, Ronald L; Bailey, Timothy S; Garg, Satish; Buckingham, Bruce A; Slover, Robert H; Klonoff, David C; Nguyen, Xuan; Shin, John; Welsh, John B; Lee, Scott W

2011-11-01

The Paradigm®Veo™ System includes a low glucose suspend (LGS) feature which suspends insulin delivery when a prespecified glucose threshold setting is reached by the associated continuous glucose monitoring (CGM) sensor. The ASPIRE (Automation to Simulate Pancreatic Insulin REsponse) study is a multicenter, in-clinic, randomized, crossover study to examine the efficacy of LGS in exercise-induced hypoglycemia. Insulin-pump users underwent two separate exercise sessions, one with the LGS feature set to suspend insulin (LGS-on) when the CGM-detected glucose concentration was ≤ 70 mg/dl and one with the LGS feature off. Exercise sessions were conducted after an overnight fast and with initial plasma glucose level as measured by the YSI 2300 STAT Plus glucose analyzer (YSI) of 100-140 mg/dl. Subjects exercised until their YSI value fell to ≤ 85 mg/dl; subsequent YSI values <70 mg/dl were recorded for up to 4 h to measure the duration and nadir of hypoglycemia. The protocol required that subjects with YSI values <50 or >300 mg/dl were rescued with carbohydrates or insulin, respectively, based on the provider's recommendation. The primary end point was comparison of duration and severity of hypoglycemia between LGS-on and LGS-off sessions. Secondary end points included areas under the glucose concentration curve, CGM sensor accuracy, and last YSI glucose. Device- and procedure-related adverse events and serious adverse events were recorded. Fifty adults and teenagers (17-58 years) with type 1 diabetes were randomized. Study completion is expected in November 2011. © 2011 Diabetes Technology Society.

A Case-Crossover Study of Heat Exposure and Injury Risk in Outdoor Agricultural Workers.

PubMed

Spector, June T; Bonauto, David K; Sheppard, Lianne; Busch-Isaksen, Tania; Calkins, Miriam; Adams, Darrin; Lieblich, Max; Fenske, Richard A

2016-01-01

Recent research suggests that heat exposure may increase the risk of traumatic injuries. Published heat-related epidemiological studies have relied upon exposure data from individual weather stations. To evaluate the association between heat exposure and traumatic injuries in outdoor agricultural workers exposed to ambient heat and internal heat generated by physical activity using modeled ambient exposure data. A case-crossover study using time-stratified referent selection among 12,213 outdoor agricultural workers with new Washington State Fund workers' compensation traumatic injury claims between 2000 and 2012 was conducted. Maximum daily Humidex exposures, derived from modeled meteorological data, were assigned to latitudes and longitudes of injury locations on injury and referent dates. Conditional logistic regression was used to estimate odds ratios of injury for a priori daily maximum Humidex categories. The mean of within-stratum (injury day and corresponding referent days) standard deviations of daily maximum Humidex was 4.8. The traumatic injury odds ratio was 1.14 (95% confidence interval 1.06, 1.22), 1.15 (95% confidence interval 1.06, 1.25), and 1.10 (95% confidence interval 1.01, 1.20) for daily maximum Humidex of 25-29, 30-33, and ≥34, respectively, compared to < 25, adjusted for self-reported duration of employment. Stronger associations were observed during cherry harvest duties in the June and July time period, compared to all duties over the entire study period. Agricultural workers laboring in warm conditions are at risk for heat-related traumatic injuries. Combined heat-related illness and injury prevention efforts should be considered in high-risk populations exposed to warm ambient conditions in the setting of physical exertion.

Bioequivalence of two commercial preparations of escitalopram oxalate/clonazepam using a liquid chromatography-electrospray mass spectrometry method.

PubMed

Agarwal, Sangita; Gowda, Kadajji Veeran; Selvan, Perumal Senthamil; Chattaraj, Tapas Kumar; Pal, Tapan Kumar

2008-01-01

A randomized, two-way crossover study was conducted in 24 fasting healthy male volunteers of Indian origin to compare the bioavailability of two brands of a fixed dose combination of escitalopram oxalate (CAS 219861-08-2) 10 mg and clonazepam (CAS 1622-61-3) 0.5 mg tablets, using Estomine-zee as test and a commercially available formulation as the reference product. The pharmacokinetics of escitalopram oxalate and clonazepam individually after oral administration of tablet formulation has been extensively evaluated in adult volunteers. However, no published data are available regarding the pharmacokinetics and bioavailability of this particular fixed dose combination. The trial was designed as a randomized, balanced, open-label, 2-period cross-over study. The drug was administered with 240 ml of water after a 10-h overnight fasting on two treatment days separated by a 21-day washout period. After dosing, serial blood samples were collected for a period of 96 h. Plasma harvested from blood was analyzed by simple rapid, selective and validated liquid chromatography-electrospray mass spectrometry (LC-ESI-MS/ MS) using diazepam (CAS 439-14-5) as an internal standard. The calibration curves were found to be linear in the range of 1-25 ng/ml and 1-10 ng/ml for escitalopram oxalate and clonazepam, respectively, with a mean correlation coefficient of more than 0.99. No statistically significant differences were obtained between the two products with respect to the mean concentration-time profiles or in the pharmacokinetic parameters, including the area under the serum concentration-time curve from the present study. Based on the statistical inferences, it was concluded that the test product is bioequivalent to the reference product. Both preparations were well tolerated with no adverse reactions throughout the study.

Using a single tablet daily to treat latent tuberculosis infection in Brazil: bioequivalence of two different isoniazid formulations (300 mg and 100 mg) demonstrated by a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry method in a randomised, crossover study

PubMed Central

Daher, André; Pitta, Luciana; Santos, Tereza; Barreira, Draurio; Pinto, Douglas

2015-01-01

The recommended treatment for latent tuberculosis (TB) infection in adults is a daily dose of isoniazid (INH) 300 mg for six months. In Brazil, INH was formulated as 100 mg tablets. The treatment duration and the high pill burden compromised patient adherence to the treatment. The Brazilian National Programme for Tuberculosis requested a new 300 mg INH formulation. The aim of our study was to compare the bioavailability of the new INH 300 mg formulation and three 100 mg tablets of the reference formulation. We conducted a randomised, single dose, open label, two-phase crossover bioequivalence study in 28 healthy human volunteers. The 90% confidence interval for the INH maximum concentration of drug observed in plasma and area under the plasma concentration vs. time curve from time zero to the last measurable concentration “time t” was 89.61-115.92 and 94.82-119.44, respectively. The main limitation of our study was that neither adherence nor the safety profile of multiple doses was evaluated. To determine the level of INH in human plasma, we developed and validated a sensitive, simple and rapid high-performance liquid chromatography-tandem mass spectrometry method. Our results showed that the new formulation was bioequivalent to the 100 mg reference product. This finding supports the use of a single 300 mg tablet daily strategy to treat latent TB. This new formulation may increase patients’ adherence to the treatment and quality of life. PMID:26038960

Clinical pharmacokinetics of Icotinib, an anti-cancer drug: evaluation of dose proportionality, food effect, and tolerability in healthy subjects.

PubMed

Liu, Dongyang; Jiang, Ji; Zhang, Li; Tan, Fenlai; Wang, Yingxiang; Zhang, Don; Hu, Pei

2014-04-01

Icotinib, an oral epidermal growth factor receptor tyrosine kinase inhibitor, has proved effectiveness in xenografted nude mice. Purpose of the present studies was to investigate tolerability and pharmacokinetics of Icotinib in healthy subjects for the first time, including dose proportionality, food effect, and tolerability. Two studies were conducted in total of 22 healthy subjects: a randomized, two-Latin-square crossover, dose proportional study (n = 12) and a randomized two-way crossover food-effect study (n = 10). Plasma concentration of Icotinib reached peak at a median Tmax of 0.75-3.5 h after single dose and then declined with a mean t1/2β of 6.02-7.83 h. Over the dose range of 100-600 mg, AUC values were proportional to dose and Cmax showed a slight saturation when dose increases. Only 0.2 % of the dose was excreted through kidney in unchanged Icotinib. After dosing 400 mg of Icotinib with high-fat and high-calorie meal, mean Cmax and AUC were significantly increased by 59 and 79 %, respectively. Three subjects experienced four adverse events (rash, increase in AST and ALT, and external injury). Rash and increased levels of AST and ALT were considered as drug-related. No serious adverse events were reported. The current work demonstrated that Icotinib was well tolerated in healthy male subjects (n = 22) over the dose range of 100-600 mg with or without food. Icotinib exposure, expressed in AUC, was proportionally increased with dose over the above dose range. Food intake significantly increased the absorption and exposure of Icotinib in healthy subjects.

Optimal Sequence of Irinotecan and Oxaliplatin-Based Regimens in Metastatic Colorectal Cancer: A Population-Based Observational Study

PubMed Central

Lin, Ching-Heng; Hwang, Wen-Li

2015-01-01

The optimal sequence of irinotecan and oxaliplatin-based regimens for metastatic colorectal cancer remains unclear. We conducted a population-based observational study by retrospectively reviewing records from Taiwan’s National Health Insurance Research Database to explore this issue. Patients aged ≥20 years with metastatic colorectal cancer newly diagnosed between 2004 and 2008 (n = 9490) were enrolled in current study. Among these 9490 patients, 3895 patients (41.04%) did not receive any chemotherapy within the first three months after catastrophic illness registration. Patients who received best supportive care were older and had higher Charlson comorbidity indexes and incidences of comorbidities than those who received irinotecan-based regimens, oxaliplatin-based regimens, and 5-fluorouracil/capecitabine alone. Patients who received irinotecan followed by oxaliplatin-based regimens and those who received the reverse sequence were further stratified into arm A (n = 542) and arm B (n = 1156), respectively. The median first time to next treatment was not significantly different between arm A and arm B (210 days vs. 196 days; p = 0.17). However, the median second time to next treatment was longer in arm A than in arm B (155 days vs. 123 days; p = 0.006), which translated into a better overall survival (487 days vs. 454 days; p = 0.02). The crossover rate was higher in arm A than in arm B (47.84% vs. 41.61%; p<0.001). Multivariate Cox regression analyses showed that overall survival was comparable between the two chemotherapy sequences (p = 0.27). Our study suggested that irinotecan followed by oxaliplatin-based regimens might be a better chemotherapy treatment option for metastatic colorectal cancer than the reverse sequence given the higher crossover rate and potential overall survival benefit. PMID:26273837

Optimal Sequence of Irinotecan and Oxaliplatin-Based Regimens in Metastatic Colorectal Cancer: A Population-Based Observational Study.

PubMed

Teng, Chieh-Lin Jerry; Wang, Chen-Yu; Chen, Yi-Huei; Lin, Ching-Heng; Hwang, Wen-Li

2015-01-01

The optimal sequence of irinotecan and oxaliplatin-based regimens for metastatic colorectal cancer remains unclear. We conducted a population-based observational study by retrospectively reviewing records from Taiwan's National Health Insurance Research Database to explore this issue. Patients aged ≥ 20 years with metastatic colorectal cancer newly diagnosed between 2004 and 2008 (n = 9490) were enrolled in current study. Among these 9490 patients, 3895 patients (41.04%) did not receive any chemotherapy within the first three months after catastrophic illness registration. Patients who received best supportive care were older and had higher Charlson comorbidity indexes and incidences of comorbidities than those who received irinotecan-based regimens, oxaliplatin-based regimens, and 5-fluorouracil/capecitabine alone. Patients who received irinotecan followed by oxaliplatin-based regimens and those who received the reverse sequence were further stratified into arm A (n = 542) and arm B (n = 1156), respectively. The median first time to next treatment was not significantly different between arm A and arm B (210 days vs. 196 days; p = 0.17). However, the median second time to next treatment was longer in arm A than in arm B (155 days vs. 123 days; p = 0.006), which translated into a better overall survival (487 days vs. 454 days; p = 0.02). The crossover rate was higher in arm A than in arm B (47.84% vs. 41.61%; p<0.001). Multivariate Cox regression analyses showed that overall survival was comparable between the two chemotherapy sequences (p = 0.27). Our study suggested that irinotecan followed by oxaliplatin-based regimens might be a better chemotherapy treatment option for metastatic colorectal cancer than the reverse sequence given the higher crossover rate and potential overall survival benefit.

Controlling charge transport mechanisms in molecular junctions: Distilling thermally induced hopping from coherent-resonant conduction.

PubMed

Kim, Hyehwang; Segal, Dvira

2017-04-28

The electrical conductance of molecular junctions may depend strongly on the temperature and weakly on molecular length, under two distinct mechanisms: phase-coherent resonant conduction, with charges proceeding via delocalized molecular orbitals, and incoherent thermally assisted multi-step hopping. While in the case of coherent conduction, the temperature dependence arises from the broadening of the Fermi distribution in the metal electrodes, in the latter case it corresponds to electron-vibration interaction effects on the junction. With the objective to distill the thermally activated hopping component, thus exposing intrinsic electron-vibration interaction phenomena on the junction, we suggest the design of molecular junctions with "spacers," extended anchoring groups that act to filter out phase-coherent resonant electrons. Specifically, we study the electrical conductance of fixed-gap and variable-gap junctions that include a tunneling block, with spacers at the boundaries. Using numerical simulations and analytical considerations, we demonstrate that in our design, resonant conduction is suppressed. As a result, the electrical conductance is dominated by two (rather than three) mechanisms: superexchange (deep tunneling) and multi-step thermally induced hopping. We further exemplify our analysis on DNA junctions with an A:T block serving as a tunneling barrier. Here, we show that the electrical conductance is insensitive to the number of G:C base-pairs at the boundaries. This indicates that the tunneling-to-hopping crossover revealed in such sequences truly corresponds to the properties of the A:T barrier.

Genetic Algorithm for Traveling Salesman Problem with Modified Cycle Crossover Operator

PubMed Central

Mohamd Shoukry, Alaa; Gani, Showkat

2017-01-01

Genetic algorithms are evolutionary techniques used for optimization purposes according to survival of the fittest idea. These methods do not ensure optimal solutions; however, they give good approximation usually in time. The genetic algorithms are useful for NP-hard problems, especially the traveling salesman problem. The genetic algorithm depends on selection criteria, crossover, and mutation operators. To tackle the traveling salesman problem using genetic algorithms, there are various representations such as binary, path, adjacency, ordinal, and matrix representations. In this article, we propose a new crossover operator for traveling salesman problem to minimize the total distance. This approach has been linked with path representation, which is the most natural way to represent a legal tour. Computational results are also reported with some traditional path representation methods like partially mapped and order crossovers along with new cycle crossover operator for some benchmark TSPLIB instances and found improvements. PMID:29209364

Genetic Algorithm for Traveling Salesman Problem with Modified Cycle Crossover Operator.

PubMed

Hussain, Abid; Muhammad, Yousaf Shad; Nauman Sajid, M; Hussain, Ijaz; Mohamd Shoukry, Alaa; Gani, Showkat

2017-01-01

Genetic algorithms are evolutionary techniques used for optimization purposes according to survival of the fittest idea. These methods do not ensure optimal solutions; however, they give good approximation usually in time. The genetic algorithms are useful for NP-hard problems, especially the traveling salesman problem. The genetic algorithm depends on selection criteria, crossover, and mutation operators. To tackle the traveling salesman problem using genetic algorithms, there are various representations such as binary, path, adjacency, ordinal, and matrix representations. In this article, we propose a new crossover operator for traveling salesman problem to minimize the total distance. This approach has been linked with path representation, which is the most natural way to represent a legal tour. Computational results are also reported with some traditional path representation methods like partially mapped and order crossovers along with new cycle crossover operator for some benchmark TSPLIB instances and found improvements.

Randomized crossover clinical trial of real and sham peripheral prism glasses for hemianopia.

PubMed

Bowers, Alex R; Keeney, Karen; Peli, Eli

2014-02-01

There is a major lack of randomized controlled clinical trials evaluating the efficacy of prismatic treatments for hemianopia. Evidence for their effectiveness is mostly based on anecdotal case reports and open-label evaluations without a control condition. To evaluate the efficacy of real relative to sham peripheral prism glasses for patients with complete homonymous hemianopia. Double-masked, randomized crossover trial at 13 study sites, including the Peli laboratory at Schepens Eye Research Institute, 11 vision rehabilitation clinics in the United States, and 1 in the United Kingdom. Patients were 18 years or older with complete homonymous hemianopia for at least 3 months and without visual neglect or significant cognitive decline. Patients were allocated by minimization into 2 groups. One group received real (57-prism diopter) oblique and sham (<5-prism diopter) horizontal prisms; the other received real horizontal and sham oblique, in counterbalanced order. Each crossover period was 4 weeks. The primary outcome was the overall difference, across the 2 periods of the crossover, between the proportion of participants who wanted to continue with (said yes to) real prisms and the proportion who said yes to sham prisms. The secondary outcome was the difference in perceived mobility improvement between real and sham prisms. Of 73 patients randomized, 61 completed the crossover. A significantly higher proportion said yes to real than sham prisms (64% vs 36%; odds ratio, 5.3; 95% CI, 1.8-21.0). Participants who continued wear after 6 months reported greater improvement in mobility with real than sham prisms at crossover end (P = .002); participants who discontinued wear reported no difference. Real peripheral prism glasses were more helpful for obstacle avoidance when walking than sham glasses, with no differences between the horizontal and oblique designs. Peripheral prism glasses provide a simple and inexpensive mobility rehabilitation intervention for hemianopia. clinicaltrials.gov Identifier: NCT00494676.

Muscle activation levels of the gluteus maximus and medius during standing hip-joint strengthening exercises using elastic-tubing resistance.

PubMed

Youdas, James W; Adams, Kady E; Bertucci, John E; Brooks, Koel J; Nelson, Meghan M; Hollman, John H

2014-02-01

No published studies have compared muscle activation levels simultaneously for the gluteus maximus and medius muscles of stance and moving limbs during standing hip-joint strengthening while using elastic-tubing resistance. To quantify activation levels bilaterally of the gluteus maximus and medius during resisted lower-extremity standing exercises using elastic tubing for the cross-over, reverse cross-over, front-pull, and back-pull exercise conditions. Repeated measures. Laboratory. 26 active and healthy people, 13 men (25 ± 3 y) and 13 women (24 ± 1 y). Subjects completed 3 consecutive repetitions of lower-extremity exercises in random order. Surface electromyographic (EMG) signals were normalized to peak activity in the maximum voluntary isometric contraction (MVIC) trial and expressed as a percentage. Magnitudes of EMG recruitment were analyzed with a 2 × 4 repeated-measures ANOVA for each muscle (α = .05). For the gluteus maximus an interaction between exercise and limb factor was significant (F3,75 = 21.5; P < .001). The moving-limb gluteus maximus was activated more than the stance limb's during the back-pull exercise (P < .001), and moving-limb gluteus maximus muscle recruitment was greater for the back-pull exercise than for the cross-over, reverse cross-over, and front-pull exercises (P < .001). For the gluteus medius an interaction between exercise and limb factor was significant (F3,75 = 3.7; P < .03). Gluteus medius muscle recruitment (% MVIC) was greater in the stance limb than moving limb when performing the front-pull exercise (P < .001). Moving-limb gluteus medius muscle recruitment was greater for the reverse cross-over exercise than for the cross-over, front-pull, and back-pull exercises (P < .001). From a clinical standpoint there is no therapeutic benefit to selectively activate the gluteus maximus and gluteus medius muscles on the stance limb by resisting sagittal- and frontal-plane hip movements on the moving limb using resistance supplied by elastic tubing.

Microfluidic Device with Tunable Post Arrays and Integrated Electrodes for Studying Cellular Release

PubMed Central

Selimovic, Asmira; Erkal, Jayda L.; Spence, Dana M.; Martin, R. Scott

2015-01-01

In this paper, we describe the development of a planar, pillar array device that can be used to image either side of a tunable membrane, as well as sample and detect small molecules in a cell-free region of the microchip. The pores are created by sealing two parallel PDMS microchannels (a cell channel and a collector channel) over a gold pillar array (5 or 10 µm in height), with the device being characterized and optimized for small molecule cross-over while excluding a flowing cell line (here, red blood cells, RBCs). The device was characterized in terms of the flow rate dependence of cross-over of analyte and cell exclusion as well as the ability to perform amperometric detection of catechol and nitric oxide (NO) as they cross-over into the collector channel. Using catechol as the test analyte, the limits of detection (LOD) of the cross-over for the 10 µm and 5 µm pillar array heights were shown to be 50 nM and 106 nM, respectively. Detection of NO was made possible with a glassy carbon detection electrode (housed in the collector channel) modified with Pt-black and Nafion, to enhance sensitivity and selectivity, respectively. Reproducible cross-over of NO as a function of concentration resulted in a linear correlation (r2 = 0.995, 7.6 µM - 190 µM), with an LOD for NO of 230 nM on the glassy carbon-Pt-black-0.05% Nafion electrode. The applicability of the device was demonstrated by measuring the NO released from hypoxic RBCs, with the device allowing the released NO to cross-over into a cell free channel where it was detected in close to real-time. This type of device is an attractive alternative to the use of 3-dimensional devices with polycarbonate membranes, as either side of the membrane can be imaged and facile integration of electrochemical detection is possible. PMID:25105251

Randomized controlled trial of nettle sting for treatment of base-of-thumb pain.

PubMed Central

Randall, C; Randall, H; Dobbs, F; Hutton, C; Sanders, H

2000-01-01

There are numerous published references to use of nettle sting for arthritis pain but no randomized controlled trials have been reported. We conducted a randomized controlled double-blind crossover study in 27 patients with osteoarthritic pain at the base of the thumb or index finger. Patients applied stinging nettle leaf (Urtica dioica) daily for one week to the painful area. The effect of this treatment was compared with that of placebo, white deadnettle leaf (Lamium album), for one week after a five-week washout period. Observations of pain and disability were recorded for the twelve weeks of the study. After one week's treatment with nettle sting, score reductions on both visual analogue scale (pain) and health assessment questionnaire (disability) were significantly greater than with placebo (P = 0.026 and P = 0.0027). PMID:10911825

Can the scaling behavior of electric conductivity be used to probe the self-organizational changes in solution with respect to the ionic liquid structure? The case of [C8MIM][NTf2].

PubMed

Paluch, Marian; Wojnarowska, Zaneta; Goodrich, Peter; Jacquemin, Johan; Pionteck, Jürgen; Hensel-Bielowka, Stella

2015-08-28

Electrical conductivity of the supercooled ionic liquid [C8MIM][NTf2], determined as a function of temperature and pressure, highlights strong differences in its ionic transport behavior between low and high temperature regions. To date, the crossover effect which is very well known for low molecular van der Waals liquids has been rarely described for classical ionic liquids. This finding highlights that the thermal fluctuations could be dominant mechanisms driving the dramatic slowing down of ion motions near Tg. An alternative way to analyze separately low and high temperature dc-conductivity data using a density scaling approach was then proposed. Based on which a common value of the scaling exponent γ = 2.4 was obtained, indicating that the applied density scaling is insensitive to the crossover effect. By comparing the scaling exponent γ reported herein along with literature data for other ionic liquids, it appears that γ decreases by increasing the alkyl chain length on the 1-alkyl-3-methylimidazolium-based ionic liquids. This observation may be related to changes in the interaction between ions in solution driven by an increase in the van der Waals type interaction by increasing the alkyl chain length on the cation. This effect may be related to changes in the ionic liquid nanostructural organization with the alkyl chain length on the cation as previously reported in the literature based on molecular dynamic simulations. In other words, the calculated scaling exponent γ may be then used as a key parameter to probe the interaction and/or self-organizational changes in solution with respect to the ionic liquid structure.

The acute effects of baobab fruit ( Adansonia digitata) on satiety in healthy adults.

PubMed

Garvey, Rebecca; Clegg, Miriam; Coe, Shelly

2017-06-01

The baobab fruit is high in both dietary fibre and polyphenols and therefore may increase satiety. The aim of the study was to measure the effects of baobab fruit extract on satiety. The study was conducted on 20 healthy participants. The study was a one-day single-blind crossover design. Participants were randomised to either a test smoothie consisting of 15 g of baobab extract or a control smoothie without the addition of baobab. Subjective ratings of satiety were taken on visual analogue scales immediately pre-consumption and then post-consumption, and energy intake at a post ad libitum meal was recorded. Subjective measures of hunger were reduced following the test smoothie compared with the control ( p < 0.05). There was no significant difference in calorie intake at an ad libitum meal. This research has positive implications for the use of baobab for reducing hunger, possibly having a positive effect on weight maintenance.

Chitosan and alginate types of bio-membrane in fuel cell application: An overview

NASA Astrophysics Data System (ADS)

Shaari, N.; Kamarudin, S. K.

2015-09-01

The major problems of polymer electrolyte membrane fuel cell technology that need to be highlighted are fuel crossovers (e.g., methanol or hydrogen leaking across fuel cell membranes), CO poisoning, low durability, and high cost. Chitosan and alginate-based biopolymer membranes have recently been used to solve these problems with promising results. Current research in biopolymer membrane materials and systems has focused on the following: 1) the development of novel and efficient biopolymer materials; and 2) increasing the processing capacity of membrane operations. Consequently, chitosan and alginate-based biopolymers seek to enhance fuel cell performance by improving proton conductivity, membrane durability, and reducing fuel crossover and electro-osmotic drag. There are four groups of chitosan-based membranes (categorized according to their reaction and preparation): self-cross-linked and salt-complexed chitosans, chitosan-based polymer blends, chitosan/inorganic filler composites, and chitosan/polymer composites. There are only three alginate-based membranes that have been synthesized for fuel cell application. This work aims to review the state-of-the-art in the growth of chitosan and alginate-based biopolymer membranes for fuel cell applications.

Non Fermi Liquid Crossovers in a Quasi-One-Dimensional Conductor in an Inclined Magnetic Field

NASA Astrophysics Data System (ADS)

Lebed, Andrei

We consider a theoretical problem of electron-electron scattering time in a quasi-one-dimensional (Q1D) conductor in a magnetic field, perpendicular to its conducting axis. We show that inverse electron-electron scattering time becomes of the order of characteristic electron energy, 1 / τ ~ ɛ ~ T , in a high magnetic field, directed far from the main crystallographic axes, which indicates breakdown of the Fermi liquid theory. In a magnetic field, directed close to one of the main crystallographic axis, inverse electron-electron scattering time becomes much smaller than characteristic electron energy and, thus, applicability of Fermi liquid theory restores. We suggest that there exist crossovers between Fermi liquid and some non Fermi liquid states in a strong enough inclined magnetic field. Application of our results to the Q1D conductor (Per)2Au(mnt)2 shows that it has to be possible to observe the above mentioned phenomenon in feasibly high magnetic fields of the order of H >=H* ~= 25 T . It was partially supported by NFS grant DMR-1104512.

Dual-frequency dielectrophoretic levitation of Canola protoplasts

PubMed Central

Kaler, Karan V. I. S.; Xie, Jing-Ping; Jones, Thomas B.; Paul, Reginald

1992-01-01

A novel dual-frequency excitation technique is introduced which permits investigation of the low-frequency dispersion of Canola plant protoplasts using feedback-controlled dielectrophoretic levitation. The upper and intermediate frequency spectra obtained using the new technique are generally consistent with previous work. However, below some cross-over frequency fOL, the protoplasts exhibit an apparent positive dielectrophoretic response that is not predicted by conventional theory. This cross-over frequency is linearly related to suspension conductivity, virtually independent of the suspension pH, and inversely proportional to the square of the cell radius. Examination of the complex Clausius-Mossotti polarization coefficient reveals that the observed positive dielectrophoretic response can not be accounted for in terms of Maxwell-Wagner polarization associated with a conventional layered model for the protoplast. The failure of straightforward enhancements to the protoplast model in explaining the low frequency behavior may indicate the presence of an electrophoretic contribution to the net observable force on the particle. To account for such fluid mechanical effects, it will be necessary to modify the existing dielectrophoretic force formulation. PMID:19431842

Stretched-to-compressed-exponential crossover observed in the electrical degradation kinetics of some spinel-metallic screen-printed structures

NASA Astrophysics Data System (ADS)

Balitska, V.; Shpotyuk, O.; Brunner, M.; Hadzaman, I.

2018-02-01

Thermally-induced (170 °C) degradation-relaxation kinetics is examined in screen-printed structures composed of spinel Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics with conductive Ag or Ag-Pd layered electrodes. Structural inhomogeneities due to Ag and Ag-Pd diffusants in spinel phase environment play a decisive role in non-exponential kinetics of negative relative resistance drift. If Ag migration in spinel is inhibited by Pd addition due to Ag-Pd alloy, the kinetics attains stretched exponential behavior with ∼0.58 exponent, typical for one-stage diffusion in structurally-dispersive media. Under deep Ag penetration into spinel ceramics, as for thick films with Ag-layered electrodes, the degradation kinetics drastically changes, attaining features of two-step diffusing process governed by compressed-exponential dependence with power index of ∼1.68. Crossover from stretched- to compressed-exponential kinetics in spinel-metallic structures is mapped on free energy landscape of non-barrier multi-well system under strong perturbation from equilibrium, showing transition with a character downhill scenario resulting in faster than exponential decaying.

Polaronic Nonmetal-Correlated Metal Crossover System β'-CuxV2O5 with Anharmonic Copper Oscillation and Thermoelectric Conversion Performance

NASA Astrophysics Data System (ADS)

Onoda, Masashige; Sato, Takuma

2017-12-01

The crystal structures and electronic properties of β'CuxV2O5 are explored through measurements of X-ray four-circle diffraction, electrical resistivity, thermoelectric power, thermal conductivity, magnetization, and electron paramagnetic resonance. For various compositions with 0.243 ≤ x ≤ 0.587, the crystal structures are redetermined through the anharmonic approach of the copper displacement factors, where the anharmonicity is reduced with increasing Cu concentration. The electron transport for x ≤ 0.45 is nonmetallic due to polaron hopping and the random potential of Cu ions, while for x = 0.60, a correlated Fermi-liquid state appears with a Wilson ratio of 1.3 and a Kadowaki-Woods ratio close to the universal value for heavy-fermion systems. At around x = 0.50, the polaronic bandwidth may broaden so that the Hubbard subbands caused by the electron correlation will overlap. The nonmetallic composition in the proximity of the nonmetal-metal crossover shows a dimensionless thermoelectric power factor of 10-2 at 300 K, partly due to the anharmonic copper oscillation.

Simple Analytic Model for Nanowire Array Polarizers

NASA Astrophysics Data System (ADS)

Pelletier, Vincent; Asakawa, Koji; Wu, Mingshaw; Register, Richard; Chaikin, Paul

2006-03-01

Cylinder-forming diblock copolymers can be used to pattern nanowire arrays on a transparent substrate to be used as a polarizer, as described by Koji Asakawa in a complementary talk at this meeting. With a 33nm period, these wire arrays can polarize UV radiation, which is of great interest in lithography, astronomy and other areas. One can gain an analytical understanding of such an array made of non-perfectly conducting material of finite thickness using a model with an appropriately averaged complex dielectric function in an infinite wavelength approximation. This analysis predicts that the grid can go from an E-polarizer to an H-polarizer as the wavelength decreases below a cross-over wavelength, and experimental data confirm this cross-over. The overall response of the polarizing grid depends primarily on the plasma frequency of the metal used and the volume fraction of the nanowires, as well as the grid thickness. A numerical approach is also used to confirm the analytical model and assess departure from infinite wavelength effects. For our array dimensions, the polarization is only slightly different from this approximation for wavelengths down to 150nm.

Social Justice for Crossover Youth: The Intersection of the Child Welfare and Juvenile Justice Systems.

PubMed

Kolivoski, Karen M; Goodkind, Sara; Shook, Jeffrey J

2017-10-01

Social workers are critical to promoting racial and social justice. "Crossover youth," a term used to describe youths who have contact with both the child welfare and juvenile justice systems, are an especially vulnerable but often overlooked population with whom social workers engage. A disproportionate number of crossover youth are African American. Empirical research on crossover youth is growing, but such scholarship rarely engages with a human rights and social justice perspective. African American children and youths have a distinct place within the history and current context of the child welfare and juvenile justice systems. These systems have historically excluded them or treated them differently; now, African American youths are overrepresented in each of them, and evidence suggests they are more likely to cross over. The purpose of this article is to describe the historical and current context of crossover youth, with a particular focus on African American youths, to provide the foundation for a discussion of what social workers can do to promote racial and social justice for crossover youth, including specific implications for practice and policy, as well as broader implications for human and civil rights. © 2017 National Association of Social Workers.

Situational and contextual factors that increase the risk of harm when students drink: case-control and case-crossover investigation.

PubMed

Connor, Jennie; Cousins, Kimberly; Samaranayaka, Ari; Kypri, Kypros

2014-07-01

Better understanding of the circumstances of alcohol-related adverse events experienced by university students could identify opportunities for prevention. We aimed to identify situational and contextual factors associated with unintentional injury, assault, unsafe sex, sexual assault and drink-driving/riding amongst university students. We conducted a Web-based survey of full-time students aged 17-25 years at five New Zealand universities (n = 2683) and carried out between- and within-subjects comparisons (case-control and case-crossover, respectively) of situational and contextual characteristics of events in the last seven days and control drinking occasions. The response fraction was 49%. For the seven days preceding the survey, 4.9% of women and 7.4% of men reported at least one of the defined events while they were drinking or soon after. The number of drinking locations and getting drunker than expected were strongly associated with risk of an event in both case-control and case-crossover models, independent of consumption. Total number of drinks, drinking later and into the morning, and drinking with close friends were also associated with increased risk in the case-control analysis. No gender difference was seen after controlling for drinking and contextual factors. Strategies to reduce the duration and volume of alcohol consumption, including earlier closing of licensed premises, should be considered as countermeasures for alcohol-related adverse events. The use of two different comparison groups for the circumstances of adverse events when drinking can strengthen inferences about the contribution of contextual factors. © 2014 Australasian Professional Society on Alcohol and other Drugs.

Short-term effects of crossover treatment with silodosin and tamsulosin hydrochloride for lower urinary tract symptoms associated with benign prostatic hyperplasia.

PubMed

Miyakita, Hideshi; Yokoyama, Eiji; Onodera, Yasutada; Utsunomiya, Takuji; Tokunaga, Masatoshi; Tojo, Takanori; Fujii, Noriteru; Yanada, Shuichi

2010-10-01

To compare the efficacy and safety of silodosin and tamsulosin in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) by a randomized crossover method. BPH patients with the complaint of LUTS were included in this study, and were randomly divided into two groups: a silodosin-preceding group (4 weeks of twice-daily administration of silodosin at 4 mg, followed by 4 weeks of once-daily administration of tamsulosin at 0.2 mg) or a tamsulosin-preceding group (4 weeks' administration of tamsulosin, followed by 4 weeks' administration of silodosin). No drug withdrawal period was provided when switching the drug. In the first treatment period, both drugs significantly improved the International Prostate Symptom Score total score, but the improvement by silodosin was significantly superior to that by tamsulosin. After crossover treatment, significant improvement was observed only with silodosin treatment. Moreover, intergroup comparison of changes revealed that silodosin showed significant improvement of straining and nocturia with first and crossover treatments, respectively, compared with tamsulosin. Silodosin also significantly improved quality of life (QOL) score in both treatment periods, while tamsulosin significantly improved QOL score only in the first treatment period. The most frequent adverse drug reaction was ejaculatory disorder with silodosin; however, the incidence of dizziness with silodosin was similar to that with tamsulosin. In BPH/LUTS patients, silodosin exhibits excellent efficacy in improving subjective symptoms in both initial and crossover treatment, and it appears to improve the QOL of patients. © 2010 The Japanese Urological Association.

Differential effects of the mismatch repair genes MSH2 and MSH3 on homeologous recombination in Saccharomyces cerevisiae.

PubMed

Selva, E M; Maderazo, A B; Lahue, R S

1997-12-01

The products of the yeast mismatch repair genes MSH2 and MSH3 participate in the inhibition of genetic recombination between homeologous (divergent) DNA sequences. In strains deficient for these genes, homeologous recombination rates between repeated elements are elevated due to the loss of this inhibition. In this study, the effects of these mutations were further analyzed by quantitation of mitotic homeologous recombinants as crossovers, gene conversions or exceptional events in wild-type, msh2, msh3 and msh2 msh3 mutant strains. When homeologous sequences were present as a direct repeat in one orientation, crossovers and gene conversions were elevated in msh2, msh3 and msh2 msh3 strains. The increases were greater in the msh2 msh3 double mutant than in either single mutant. When the order of the homeologous sequences was reversed, the msh2 mutation again yielded increased rates of crossovers and gene conversions. However, in an msh3 strain, gene conversions occurred at higher levels but interchromosomal crossovers were not increased and intrachromosomal crossovers were reduced relative to wild type. The msh2 msh3 double mutant behaved like the msh2 single mutant in this orientation. Control strains harboring homologous duplications were largely but not entirely unaffected in mutant strains, suggesting specificity for the mismatched intermediates of homeologous recombination. In all strains, very few (< 10%) recombinants could be attributed to exceptional events. These results suggest that MSH2 and MSH3 can function differentially to control homeologous exchanges.

All in the family: Work-family enrichment and crossover among farm couples.

PubMed

Sprung, Justin M; Jex, Steve M

2017-04-01

This study expands upon the contextualization of the work-family interface by examining positive work-family experiences within the farming industry. Both individual and crossover effects were examined among a sample of 217 married farm couples. Results demonstrated multiple significant relationships between self-reported attitudes, work-family enrichment, and health outcomes. In addition, crossover effects reveal the importance of individual attitudes (husband work engagement and wife farm satisfaction) for spousal work-family enrichment and health outcomes. Furthermore, individual work-family enrichment was positively related to spousal psychological health and negatively related to spousal physical symptoms. Many of these findings remained significant after controlling for work-family conflict. Overall, our results suggest the potential beneficial impact of the integrated work-family dynamic associated with the farming profession for positive work-family experiences. Implications of these findings, as well as directions for future research, are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Density and spin modes in imbalanced normal Fermi gases from collisionless to hydrodynamic regime

NASA Astrophysics Data System (ADS)

Narushima, Masato; Watabe, Shohei; Nikuni, Tetsuro

2018-03-01

We study the mass- and population-imbalance effect on density (in-phase) and spin (out-of-phase) collective modes in a two-component normal Fermi gas. By calculating the eigenmodes of the linearized Boltzmann equation as well as the density/spin dynamic structure factor, we show that mass- and population-imbalance effects offer a variety of collective mode crossover behaviors from collisionless to hydrodynamic regimes. The mass-imbalance effect shifts the crossover regime to the higher-temperature, and a significant peak of the spin dynamic structure factor emerges only in the collisionless regime. This is in contrast to the case of mass- and population-balanced normal Fermi gases, where the spin dynamic response is always absent. Although the population-imbalance effect does not shift the crossover regime, the spin dynamic structure factor survives both in the collisionless and hydrodynamic regimes.

The dynamical crossover phenomenon in bulk water, confined water and protein hydration water.

PubMed

Mallamace, Francesco; Corsaro, Carmelo; Baglioni, Piero; Fratini, Emiliano; Chen, Sow-Hsin

2012-02-15

We discuss a phenomenon regarding water that was until recently a subject of scientific controversy, i.e. the dynamical crossover from fragile-to-strong glass-forming material, for both bulk and protein hydration water. Such a crossover is characterized by a temperature T(L) at which significant dynamical changes occur, such as violation of the Stokes-Einstein relation and changes of behaviour of homologous transport parameters such as the density relaxation time and the viscosity. In this respect we will consider carefully the dynamic properties of water-protein systems. More precisely, we will study proteins and their hydration water as far as bulk and confined water. In order to clarify the controversy we will discuss in a comparative way many previous and new experimental data that have emerged using different techniques and molecular dynamic simulation (MD). We point out the reasons for the different dynamical findings from the use of different experimental techniques.

How job demands affect partners' experience of exhaustion: integrating work-family conflict and crossover theory.

PubMed

Bakker, Arnold B; Demerouti, Evangelia; Dollard, Maureen F

2008-07-01

This study among 168 couples of dual-earner parents uses insights from previous work-family conflict and crossover research to propose an integrative model delineating how job demands experienced by men and women carry over to the home domain. The authors hypothesized that for both men and women, job demands foster their own work-family conflict (WFC), which in turn contributes to their partners' home demands, family-work conflict (FWC), and exhaustion. In addition, they hypothesized that social undermining mediates the relationship between individuals' WFC and their partners' home demands. The results of structural equation modeling analyses provided strong support for the proposed model. The hypothesis that gender would moderate the model relationships was rejected. These findings integrate previous findings on work-family conflict and crossover theories and suggest fluid boundaries between the work and home domains.

Melting of Boltzmann particles in different 2D trapping potential

NASA Astrophysics Data System (ADS)

Bhattacharya, Dyuti; Filinov, Alexei; Ghosal, Amit; Bonitz, Michael

2015-03-01

We analyze the quantum melting of two dimensional Wigner solid in several confined geometries and compare them with corresponding thermal melting in a purely classical system. Our results show that the geometry play little role in deciding the crossover quantum parameter nX, as the effects from boundary is well screened by the quantum zero point motion. The unique phase diagram in the plane of thermal and quantum fluctuations determined from independent melting criteria separates out the Wigner molecule ``phase'' from the classical and quantum ``liquids''. An intriguing signature of weakening liquidity with increasing temperature T have been found in the extreme quantum regime (n). This crossover is associated with production of defects, just like in case of thermal melting, though the role of them in determining the mechanism of the crossover appears different. Our study will help comprehending melting in a variety of experimental realization of confined system - from quantum dots to complex plasma.

Matrix-assisted relaxation in Fe(phen)2(NCS)2 spin-crossover microparticles, experimental and theoretical investigations

NASA Astrophysics Data System (ADS)

Enachescu, Cristian; Tanasa, Radu; Stancu, Alexandru; Tissot, Antoine; Laisney, Jérôme; Boillot, Marie-Laure

2016-07-01

In this study, we present the influence of the embedding matrix on the relaxation of Fe(phen)2(NCS)2 (phen = 1,10-phenanthroline) spin-transition microparticles as revealed by experiments and provide an explanation within the framework of an elastic model based on a Monte-Carlo method. Experiments show that the shape of the high-spin → low-spin relaxation curves is drastically changed when the particles are dispersed in glycerol. This effect was considered in the model by means of interactions between the microparticles and the matrix. A faster start of the relaxation for microparticles embedded in glycerol is due to an initial positive local pressure acting on the edge spin-crossover molecules from the matrix side. This local pressure diminishes and eventually becomes negative during relaxation, as an effect of the decrease of the volume of spin-crossover microparticles from high-spin to low-spin.

Ambient temperature and coronary heart disease mortality in Beijing, China: a time series study

PubMed Central

2012-01-01

Background Many studies have examined the association between ambient temperature and mortality. However, less evidence is available on the temperature effects on coronary heart disease (CHD) mortality, especially in China. In this study, we examined the relationship between ambient temperature and CHD mortality in Beijing, China during 2000 to 2011. In addition, we compared time series and time-stratified case-crossover models for the non-linear effects of temperature. Methods We examined the effects of temperature on CHD mortality using both time series and time-stratified case-crossover models. We also assessed the effects of temperature on CHD mortality by subgroups: gender (female and male) and age (age > =65 and age < 65). We used a distributed lag non-linear model to examine the non-linear effects of temperature on CHD mortality up to 15 lag days. We used Akaike information criterion to assess the model fit for the two designs. Results The time series models had a better model fit than time-stratified case-crossover models. Both designs showed that the relationships between temperature and group-specific CHD mortality were non-linear. Extreme cold and hot temperatures significantly increased the risk of CHD mortality. Hot effects were acute and short-term, while cold effects were delayed by two days and lasted for five days. The old people and women were more sensitive to extreme cold and hot temperatures than young and men. Conclusions This study suggests that time series models performed better than time-stratified case-crossover models according to the model fit, even though they produced similar non-linear effects of temperature on CHD mortality. In addition, our findings indicate that extreme cold and hot temperatures increase the risk of CHD mortality in Beijing, China, particularly for women and old people. PMID:22909034

The effects of particulate air pollution on daily deaths: a multi-city case crossover analysis

PubMed Central

Schwartz, J

2004-01-01

Background: Numerous studies have reported that day-to-day changes in particulate air pollution are associated with day-to-day changes in deaths. Recently, several reports have indicated that the software used to control for season and weather in some of these studies had deficiencies. Aims: To investigate the use of the case-crossover design as an alternative. Methods: This approach compares the exposure of each case to their exposure on a nearby day, when they did not die. Hence it controls for seasonal patterns and for all slowly varying covariates (age, smoking, etc) by matching rather than complex modelling. A key feature is that temperature can also be controlled by matching. This approach was applied to a study of 14 US cities. Weather and day of the week were controlled for in the regression. Results: A 10 µg/m3 increase in PM10 was associated with a 0.36% increase in daily deaths from internal causes (95% CI 0.22% to 0.50%). Results were little changed if, instead of symmetrical sampling of control days the time stratified method was applied, when control days were matched on temperature, or when more lags of winter time temperatures were used. Similar results were found using a Poisson regression, but the case-crossover method has the advantage of simplicity in modelling, and of combining matched strata across multiple locations in a single stage analysis. Conclusions: Despite the considerable differences in analytical design, the previously reported associations of particles with mortality persisted in this study. The association appeared quite linear. Case-crossover designs represent an attractive method to control for season and weather by matching. PMID:15550600

The effect of LHRH antagonist cetrorelix in crossover conditioned media from epithelial (BPH-1) and stromal (WPMY-1) prostate cells.

PubMed

Siejka, A; Schally, A V; Barabutis, N

2014-01-01

Stromal cells strictly modulate the differentiation of the normal prostate epithelium. In benign prostatic hyperplasia (BPH) tissue, the ratio of stromal to epithelial cells reaches a 5:1 ratio. In this study, we evaluated the effects of crossover conditioned media (CM) of stromal and epithelial prostate cells before and after treatment with LHRH antagonist Cetrorelix. WPMY-1 human prostate stromal cells and BPH-1 human benign prostatic hyperplasia cells were cultured in vitro and the effects of crossover conditioned media (CM) from those cells were studied. We evaluated the effect of Cetrorelix on the expression of PCNA and p53 in those cells. We then studied the effect of Cetrorelix on BPH-1 cells cultured with the CM from WPMY-1 cells, as well as the mechanisms which govern these interactions. CM from WPMY-1 cells strongly stimulated the proliferation of BPH-1 cells in a dose dependent manner, while CM from BPH-1 cells only slightly increased the proliferation of WPMY-1 cells. Cetrorelix inhibited the proliferation of both cell lines and the expression of PCNA, while the expression of p53 was increased. Cetrorelix also inhibited the proliferation of BPH-1 cells stimulated with the CM from WPMY-1 cells. In the crossover experiment, conditioned media from WPMY-1 and BPH-1 cells increased the expression of phosphorylated ERK1/2 and STAT3. Our results support previous observations on the bidirectional stromal-epithelial interactions in prostate gland and shed more light on the mechanistic action of those effects. Our study strongly supports the hypothesis that LHRH antagonists may be beneficial for BPH prevention and treatment. © Georg Thieme Verlag KG Stuttgart · New York.

AC conductivity scaling behavior in grain and grain boundary response regime of fast lithium ionic conductors

NASA Astrophysics Data System (ADS)

Mariappan, C. R.

2014-05-01

AC conductivity spectra of Li-analogues NASICON-type Li1.5Al0.5Ge1.5P3O12 (LAGP), Li-Al-Ti-P-O (LATP) glass-ceramics and garnet-type Li7La2Ta2O13 (LLTO) ceramic are analyzed by universal power law and Summerfield scaling approaches. The activation energies and pre-exponential factors of total and grain conductivities are following the Meyer-Neldel (M-N) rule for NASICON-type materials. However, the garnet-type LLTO material deviates from the M-N rule line of NASICON-type materials. The frequency- and temperature-dependent conductivity spectra of LAGP and LLTO are superimposed by Summerfield scaling. The scaled conductivity curves of LATP are not superimposed at the grain boundary response region. The superimposed conductivity curves are observed at cross-over frequencies of grain boundary response region for LATP by incorporating the exp ( {{{ - (EAt - EAg )} {{{ - (EAt - EAg )} {kT}}} ) factor along with Summerfield scaling factors on the frequency axis, where EAt and EAg are the activation energies of total and grain conductivities, respectively.

Prevalence and gender patterns of mental health problems in German youth with experience of violence: the KiGGS study.

PubMed

Schlack, Robert; Petermann, Franz

2013-07-02

Research examining mental health in violence-affected youth in representative samples is rare. Using data from the nationally representative German Health Interview and Examination Survey for Children and Adolescents (KiGGS) this study reports on gender-specific prevalence rates and associations of a broad range of internalizing and externalizing mental health problems: emotional problems, conduct problems, ADHD, disordered eating, somatic pain and substance use in youth variously affected by violence. While internalizing is generally more common in girls and externalizing in boys, observations of prior non-normative studies suggest reverse associations once an individual is affected by violence. The occurrence of such "gender cross-over effects" is therefore examined in a representative sample. The sample consisted of 6,813 adolescents aged 11 to 17 from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS): Applying multivariate logistic regression analyses, associations between each type of violence history and mental health indicator were determined for perpetrators, victims, and perpetrating victims of youth violence. Moderating effects of gender were examined by using product term interaction. Victim status was associated primarily with internalizing problems, while perpetrators were more prone to externalizing problems. Perpetrating victims stood out with respect to the number and strength of risk associations with all investigated mental health indicators. However, the risk profiles of all violence-affected youth included both internalizing and externalizing mental health problems. Gender cross-over effects were found for girls and boys: despite lower overall prevalence, girls affected by violence were at far higher risk for conduct problems and illicit drug use; by contrast, somatic pain, although generally lower in males, was positively associated with perpetrator status and perpetrating victim status in boys. All violence-affected youth exhibited significantly higher rates of cumulative mental health problems. The results highlight the importance of violence for the mental health of youth. They reveal a particular vulnerability as a function of gender. Implications for policy making, clinical practice and research are discussed.

Prevalence and gender patterns of mental health problems in German youth with experience of violence: the KiGGS study

PubMed Central

2013-01-01

Background Research examining mental health in violence-affected youth in representative samples is rare. Using data from the nationally representative German Health Interview and Examination Survey for Children and Adolescents (KiGGS) this study reports on gender-specific prevalence rates and associations of a broad range of internalizing and externalizing mental health problems: emotional problems, conduct problems, ADHD, disordered eating, somatic pain and substance use in youth variously affected by violence. While internalizing is generally more common in girls and externalizing in boys, observations of prior non-normative studies suggest reverse associations once an individual is affected by violence. The occurrence of such “gender cross-over effects” is therefore examined in a representative sample. Methods The sample consisted of 6,813 adolescents aged 11 to 17 from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS): Applying multivariate logistic regression analyses, associations between each type of violence history and mental health indicator were determined for perpetrators, victims, and perpetrating victims of youth violence. Moderating effects of gender were examined by using product term interaction. Results Victim status was associated primarily with internalizing problems, while perpetrators were more prone to externalizing problems. Perpetrating victims stood out with respect to the number and strength of risk associations with all investigated mental health indicators. However, the risk profiles of all violence-affected youth included both internalizing and externalizing mental health problems. Gender cross-over effects were found for girls and boys: despite lower overall prevalence, girls affected by violence were at far higher risk for conduct problems and illicit drug use; by contrast, somatic pain, although generally lower in males, was positively associated with perpetrator status and perpetrating victim status in boys. All violence-affected youth exhibited significantly higher rates of cumulative mental health problems. Conclusions The results highlight the importance of violence for the mental health of youth. They reveal a particular vulnerability as a function of gender. Implications for policy making, clinical practice and research are discussed. PMID:23819775

Low-temperature thermoelectric, galvanomagnetic, and thermodynamic properties of the type-I clathrate Ba8AuxSi46-x

NASA Astrophysics Data System (ADS)

Aydemir, U.; Candolfi, C.; Ormeci, A.; Oztan, Y.; Baitinger, M.; Oeschler, N.; Steglich, F.; Grin, Yu.

2011-11-01

Polycrystalline samples of the clathrate Ba8AuxSi46-x were synthesized for 0.2 ⩽ x ⩽ 10. The homogeneity range of the type-I clathrate phase was determined to be 3.63 ⩽ x ⩽ 6.10 after annealing at 900 °C, while a lower Au concentration (x ≈ 2.2) was obtained by steel-quenching. Quasisingle phase materials were obtained for 4.10 ⩽ x ⩽ 6.10. In this composition range, thermoelectric properties, including electrical resistivity, thermopower, and thermal conductivity, were investigated between 2 and 350 K. These experiments were complemented by low-temperature specific heat and Hall-effect measurements (2-300 K). First-principles calculations were carried out to determine the evolution of the electronic structure as a function of x. Both theoretical and experimental results evidence a progressive evolution, with the Au content, from a metallic-like behavior towards a highly doped semiconducting state which develops around x = 5.43. At this concentration, a crossover from n- to p-type conduction occurs, suggesting that the present system satisfies the Zintl-Klemm concept, which predicts a transition at x = 5.33. This crossover is traced by Hall-effect data indicating a dominant electronlike response for x ⩽ 5.43, which turns into a holelike signal at higher x values. Analysis of the data based on a single-parabolic-band model under the assumption of a single scattering mechanism of the charge carriers proved to adequately describe the transport properties in the compositional range investigated. Interestingly, the temperature dependence of the lattice thermal conductivity is strongly influenced by the Au concentration: the typical behavior of crystalline insulators in the n-type compounds evolves into a glasslike dependence in the p-type samples. The series Ba8AuxSi46-x thus provides an excellent testing ground for the interplay between crystal structure, electronic properties, and lattice thermal conductivity in type-I clathrates.

Evolution of the baryon asymmetry through the electroweak crossover in the presence of a helical magnetic field

NASA Astrophysics Data System (ADS)

Kamada, Kohei; Long, Andrew J.

2016-12-01

We elaborate upon the model of baryogenesis from decaying magnetic helicity by focusing on the evolution of the baryon number and magnetic field through the Standard Model electroweak crossover. The baryon asymmetry is determined by a competition between the helical hypermagnetic field, which sources baryon number, and the electroweak sphaleron, which tends to wash out baryon number. At the electroweak crossover, both of these processes become inactive; the hypermagnetic field is converted into an electromagnetic field, which does not source baryon number, and the weak gauge boson masses grow, suppressing the electroweak sphaleron reaction. An accurate prediction of the relic baryon asymmetry requires a careful treatment of the crossover. We extend our previous study [K. Kamada and A. J. Long, Phys. Rev. D 94, 063501 (2016)], taking into account the gradual conversion of the hypermagnetic into the electromagnetic field. If the conversion is not completed by the time of sphaleron freeze-out, as both analytic and numerical studies suggest, the relic baryon asymmetry is enhanced compared to previous calculations. The observed baryon asymmetry of the Universe can be obtained for a primordial magnetic field that has a present-day field strength and coherence length of B0˜10-17 G and λ0˜10-3 pc and a positive helicity. For larger B0 the baryon asymmetry is overproduced, which may be in conflict with blazar observations that provide evidence for an intergalactic magnetic field of strength B0≳10-14 - 16 G .

Within-Subject Mediation Analysis in AB/BA Crossover Designs.

PubMed

Josephy, Haeike; Vansteelandt, Stijn; Vanderhasselt, Marie-Anne; Loeys, Tom

2015-05-01

Crossover trials are widely used to assess the effect of a reversible exposure on an outcome of interest. To gain further insight into the underlying mechanisms of this effect, researchers may be interested in exploring whether or not it runs through a specific intermediate variable: the mediator. Mediation analysis in crossover designs has received scant attention so far and is mostly confined to the traditional Baron and Kenny approach. We aim to tackle mediation analysis within the counterfactual framework and elucidate the assumptions under which the direct and indirect effects can be identified in AB/BA crossover studies. Notably, we show that both effects are identifiable in certain statistical models, even in the presence of unmeasured time-independent (or upper-level) confounding of the mediator-outcome relation. Employing the mediation formula, we derive expressions for the direct and indirect effects in within-subject designs for continuous outcomes that lend themselves to linear modelling, under a large variety of settings. We discuss an estimation approach based on regressing differences in outcomes on differences in mediators and show how to allow for period effects as well as different types of moderation. The performance of this approach is compared to other existing methods through simulations and is illustrated with data from a neurobehavioural study. Lastly, we demonstrate how a sensitivity analysis can be performed that is able to assess the robustness of both the direct and indirect effect against violation of the "no unmeasured lower-level mediator-outcome confounding" assumption.

Performance and microbial ecology of air-cathode microbial fuel cells with layered electrode assemblies.

PubMed

Butler, Caitlyn S; Nerenberg, Robert

2010-05-01

Microbial fuel cells (MFCs) can be built with layered electrode assemblies, where the anode, proton exchange membrane (PEM), and cathode are pressed into a single unit. We studied the performance and microbial community structure of MFCs with layered assemblies, addressing the effect of materials and oxygen crossover on the community structure. Four MFCs with layered assemblies were constructed using Nafion or Ultrex PEMs and a plain carbon cloth electrode or a cathode with an oxygen-resistant polytetrafluoroethylene diffusion layer. The MFC with Nafion PEM and cathode diffusion layer achieved the highest power density, 381 mW/m(2) (20 W/m(3)). The rates of oxygen diffusion from cathode to anode were three times higher in the MFCs with plain cathodes compared to those with diffusion-layer cathodes. Microsensor studies revealed little accumulation of oxygen within the anode cloth. However, the abundance of bacteria known to use oxygen as an electron acceptor, but not known to have exoelectrogenic activity, was greater in MFCs with plain cathodes. The MFCs with diffusion-layer cathodes had high abundance of exoelectrogenic bacteria within the genus Geobacter. This work suggests that cathode materials can significantly influence oxygen crossover and the relative abundance of exoelectrogenic bacteria on the anode, while PEM materials have little influence on anode community structure. Our results show that oxygen crossover can significantly decrease the performance of air-cathode MFCs with layered assemblies, and therefore limiting crossover may be of particular importance for these types of MFCs.

Dental Students' Preference with Regard to Tactile or Visual Determination of Injection Site for an Inferior Alveolar Nerve Block in Children: A Crossover Randomized Clinical Trial.

PubMed

Ramazani, Nahid; Iranmanesh, Seyed Masoud

2016-01-01

Instruction of local anesthesia injection in an important part of dental education curricula. This study was performed to compare dental students' preference with regard to tactile or visual determination of injection site for an inferior alveolar nerve block (IANB) in children. This crossover randomized clinical trial was conducted on dental students of Zahedan Dental School who took the first practical course of pediatric dentistry in the first academic semester of 2013-14 (n=42). They were randomly divided into two groups. During the first phase, group I was instructed to find the needle insertion point for an IANB via tactile method and group II was instructed to do it visually. In the second phase, the groups received instructions for the alternate technique. Both instructions were done using live demonstrations by the same instructor and immediately after instruction the learners practiced an IANB using the taught method. A five-point Likert scale questionnaire was then filled out by the students. The preference score was determined by calculating the mean of item scores. Data were analyzed using Mann-Whitney U and Wilcoxon Singed Rank tests in SPSS 19 at P=0.05 level of significance. Thirty-eight students completed the study. By using the visual method to perform an IANB, students gained a significantly higher mean preference score (P=0.020). There was a significant difference in the preference of male students (P=0.008). Instruction of IANB by visual identification of needle insertion point is more desirable by students.

An exploratory mixed-methods crossover study comparing DVD- vs. Web-based patient decision support in three conditions: The importance of patient perspectives.

PubMed

Halley, Meghan C; Rendle, Katharine A S; Gillespie, Katherine A; Stanley, Katherine M; Frosch, Dominick L

2015-12-01

The last 15 years have witnessed considerable progress in the development of decision support interventions (DESIs). However, fundamental questions about design and format of delivery remain. An exploratory, randomized mixed-method crossover study was conducted to compare a DVD- and Web-based DESI. Randomized participants used either the Web or the DVD first, followed by the alternative format. Participants completed a questionnaire to assess decision-specific knowledge at baseline and a questionnaire and structured qualitative interview after viewing each format. Tracking software was used to capture Web utilization. Transcripts were analyzed using integrated inductive and deductive approaches. Quantitative data were analyzed using exploratory bivariate and multivariate analyses. Exploratory knowledge analyses suggest that both formats increased knowledge, with limited evidence that the DVD increased knowledge more than the Web. Format preference varied across participants: 44% preferred the Web, 32% preferred the DVD and 24% preferred 'both'. Patient discussions of preferences for DESI information structure and the importance of a patients' stage of a given decision suggest these characteristics may be important factors underlying variation in utilization, format preferences and knowledge outcomes. Our results suggest that both DESI formats effectively increase knowledge. Patients' perceptions of these two formats further suggest that there may be no single 'best' format for all patients. These results have important implications for understanding why different DESI formats might be preferable to and more effective for different patients. Further research is needed to explore the relationship between these factors and DESI utilization outcomes across diverse patient populations. © 2014 John Wiley & Sons Ltd.

Evaluation of selective cyclooxygenase-2 inhibitor-induced small bowel injury: randomized cross-over study compared with loxoprofen in healthy subjects.

PubMed

Mizukami, Kazuhiro; Murakami, Kazunari; Yamauchi, Mika; Matsunari, Osamu; Ogawa, Ryo; Nakagawa, Yoshifumi; Okimoto, Tadayoshi; Kodama, Masaaki; Fujioka, Toshio

2013-05-01

Non-steroidal anti-inflammatory drugs have the potential to injure the mucosa of the upper digestive tract and small bowel, whereas celecoxib (a selective cyclooxygenase-2 inhibitor) has less influence on the entire digestive tract mucosa. The present study was conducted to compare the extents of small bowel mucosal injury induced by celecoxib and loxoprofen (the most frequently used non-steroidal anti-inflammatory drugs in Japan). Ten healthy adult males were given celecoxib (200 mg/day, Group C) and loxoprofen (180 mg/day, Group L) in a cross-over design for 14 days, and the influence of each drug on small bowel mucosa was evaluated by comparing pre- and post-treatment capsule endoscopy findings. We measured the percentage of patients with small bowel mucosal injury following administration of these drugs as primary endpoint. Additionally, mean number of small bowel mucosal injuries per subject was analyzed as secondary endpoint. The percentage of subjects experiencing small bowel mucosal injury as primary endpoint was 10% in Group C and 70% in Group L after treatment. This magnitude of the difference of between Group C and Group L was statistically significant (P = 0.031). The number of small bowel mucosal injuries as secondary endpoint differed significantly between the two groups, and the influence of celecoxib on small bowel injury was less than that of loxoprofen. These results indicate that celecoxib has less influence on small bowel mucosa than loxoprofen and can be used safely. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

Impact of a feedback device on chest compression quality during extended manikin CPR: a randomized crossover study.

PubMed

Buléon, Clément; Delaunay, Julie; Parienti, Jean-Jacques; Halbout, Laurent; Arrot, Xavier; Gérard, Jean-Louis; Hanouz, Jean-Luc

2016-09-01

Chest compressions require physical effort leading to increased fatigue and rapid degradation in the quality of cardiopulmonary resuscitation overtime. Despite harmful effect of interrupting chest compressions, current guidelines recommend that rescuers switch every 2 minutes. The impact on the quality of chest compressions during extended cardiopulmonary resuscitation has yet to be assessed. We conducted randomized crossover study on manikin (ResusciAnne; Laerdal). After randomization, 60 professional emergency rescuers performed 2 × 10 minutes of continuous chest compressions with and without a feedback device (CPRmeter). Efficient compression rate (primary outcome) was defined as the frequency target reached along with depth and leaning at the same time (recorded continuously). The 10-minute mean efficient compression rate was significantly better in the feedback group: 42% vs 21% (P< .001). There was no significant difference between the first (43%) and the tenth minute (36%; P= .068) with feedback. Conversely, a significant difference was evident from the second minute without feedback (35% initially vs 27%; P< .001). The efficient compression rate difference with and without feedback was significant every minute, from the second minute onwards. CPRmeter feedback significantly improved chest compression depth from the first minute, leaning from the second minute and rate from the third minute. A real-time feedback device delivers longer effective, steadier chest compressions over time. An extrapolation of these results from simulation may allow rescuer switches to be carried out beyond the currently recommended 2 minutes when a feedback device is used. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of abuse liability of Tramadol among experienced drug users: Double-blind crossover randomized controlled trial.

PubMed

Das, Mrinmay; Jain, Raka; Dhawan, Anju; Kaur, Amandeep

Tramadol is a widely used opioid analgesic. Different preclinical, clinical, and postmarketing surveillance studies show conflicting results regarding abuse potential of this drug. A randomized double-blind complete crossover study was conducted at National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi. Total subjects were 10, comprising total 120 observations (each subject assessed at baseline, 5, 45, and 240 minutes). Subjects with history of substance abuse were included after detoxification and informed consent. Assessment was done using modified single dose opiate questionnaire, morphine benzedrine group (MBG), pentobarbital chlorpromazine alcohol group (PCAG), and two bipolar visual analogue scales (VAS) after administration of three drugs-Tramadol (100 mg), Buprenorphine (0.6 mg), and Placebo (Normal Saline) intramuscularly, at 5-day interval. In intra-group analysis, there was statistically significant increase in scores of all four scales from baseline to all three time points after Tramadol and Buprenorphine administration. In inter-group analysis, statistically higher scores were seen for Buprenorphine in comparison to Tramadol at 5, 45, and 240 minutes for MBG scale; the score was significantly higher for Buprenorphine in VAS for pleasurable effect at 45 and 240 minutes, but not at baseline and 5 minutes. There was no significant difference in score at any point of time between Tramadol and Buprenorphine in PCAG scale and VAS for sedative/alertness effect. The scores were statistically insignificant in case of Placebo. All the subjects liked Buprenorphine most and then Tramadol followed by Placebo. Tramadol has abuse potential (even in therapeutic doses) more than Placebo but less than or comparable to Buprenorphine.