Diffusion barriers in modified air brazes

DOEpatents

Weil, Kenneth Scott; Hardy, John S; Kim, Jin Yong; Choi, Jung-Pyung

2013-04-23

A method for joining two ceramic parts, or a ceramic part and a metal part, and the joint formed thereby. The method provides two or more parts, a braze consisting of a mixture of copper oxide and silver, a diffusion barrier, and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together. The diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze, a heterogeneous component of the braze, a separate layer bordering the braze, or combinations thereof. The oxidizable metal is selected from the group Al, Mg, Cr, Si, Ni, Co, Mn, Ti, Zr, Hf, Pt, Pd, Au, lanthanides, and combinations thereof.

Diffusion barriers in modified air brazes

DOEpatents

Weil, Kenneth Scott [Richland, WA; Hardy, John S [Richland, WA; Kim, Jin Yong [Richland, WA; Choi, Jung-Pyung [Richland, WA

2010-04-06

A method for joining two ceramic parts, or a ceramic part and a metal part, and the joint formed thereby. The method provides two or more parts, a braze consisting of a mixture of copper oxide and silver, a diffusion barrier, and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together. The diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze, a heterogeneous component of the braze, a separate layer bordering the braze, or combinations thereof. The oxidizable metal is selected from the group Al, Mg, Cr, Si, Ni, Co, Mn, Ti, Zr, Hf, Pt, Pd, Au, lanthanides, and combinations thereof.

In Situ Formation Of Reactive Barriers For Pollution Control

DOEpatents

Gilmore, Tyler J.; Riley, Robert G.

2004-04-27

A method of treating soil contamination by forming one or more zones of oxidized material in the path of percolating groundwater is disclosed. The zone or barrier region is formed by delivering an oxidizing agent into the ground for reaction with an existing soil component. The oxidizing agent modifies the existing soil component creating the oxidized zone. Subsequently when soil contaminates migrate into the zone, the oxidized material is available to react with the contaminates and degrade them into benign products. The existing soil component can be an oxidizable mineral such as manganese, and the oxidizing agent can be ozone gas or hydrogen peroxide. Soil contaminates can be volatile organic compounds. Oxidized barriers can be used single or in combination with other barriers.

Barriers and facilitators to disease-modifying antirheumatic drug use in patients with inflammatory rheumatic diseases: a qualitative theory-based study.

PubMed

Voshaar, Marieke; Vriezekolk, Johanna; van Dulmen, Sandra; van den Bemt, Bart; van de Laar, Mart

2016-10-21

Although disease-modifying anti-rheumatic drugs (DMARDs) are the cornerstone of treatment for inflammatory rheumatic diseases, medication adherence to DMARDs is often suboptimal. Effective interventions to improve adherence to DMARDs are lacking, and new targets are needed to improve adherence. The aim of the present study was to explore patients' barriers and facilitators of optimal DMARD use. These factors might be used as targets for adherence interventions. In a mixed method study design, patients (n = 120) with inflammatory arthritis (IA) completed a questionnaire based on an existing adapted Theoretical Domains Framework (TDF) to identify facilitators and barriers of DMARD use. A subgroup of these patients (n = 21) participated in focus groups to provide insights into their facilitators and barriers. The answers to the questionnaires and responses of the focus groups were thematically coded by three researchers independently and subsequently categorized. The barriers and facilitators that were reported by IA patients presented large inter-individual variations. The identified barriers and facilitators could be captured in the following domains based on an adapted TDF: (i) knowledge, (ii) emotions, (iii) attention, memory, and decision processes, (iv) social influences, (v) beliefs about capability, (vi) beliefs about consequences, (vii) motivation and goals, (viii) goal conflict, (ix) environmental context and resources, and (x) skills. Patients with IA have a variety of barriers and facilitators with regard to their DMARD use. All of these barriers and facilitators could be categorized into adapted domains of the TDF. Interventions that address individual facilitators and barriers, based on capability, opportunity, and motivation, are needed to develop strategies for medication adherence that are tailored to individual patient needs.

[Blood-nerve barrier and peripheral nerve regeneration].

PubMed

Kanda, Takashi

2013-01-01

Blood-nerve barrier (BNB) restricts the movement of soluble mediators and leukocytes from the blood contents to the peripheral nervous system (PNS) parenchyma and thus maintains the endoneurial homeostasis. However, it interferes the supply of various neurotrophic factors from the blood constituents and stops the drainage of toxic substances out of the PNS parenchyma, resulting in the inhibition of peripheral nerve regeneration. If the manipulation of BNB function is possible, regeneration of peripheral nerve may be facilitated via the alteration of peripheral nerve microenvironment and ample supply of neurotrophic substances. A possible method to manipulate the BNB for therapeutic purposes is to modify the endothelial function using siRNAs, oligonucleotides and virus vectors. Another possible method is to modify BNB pericytes: small hydrophobic substances that can reach the pericyte membrane through the endothelial monolayer and strengthen the pericytic activity, including the release of various cytokines/chemokines that influence endothelial function, may also be useful as drug candidates to control the BNB function.

A network-analysis-based comparative study of the throughput behavior of polymer melts in barrier screw geometries

NASA Astrophysics Data System (ADS)

Aigner, M.; Köpplmayr, T.; Kneidinger, C.; Miethlinger, J.

2014-05-01

Barrier screws are widely used in the plastics industry. Due to the extreme diversity of their geometries, describing the flow behavior is difficult and rarely done in practice. We present a systematic approach based on networks that uses tensor algebra and numerical methods to model and calculate selected barrier screw geometries in terms of pressure, mass flow, and residence time. In addition, we report the results of three-dimensional simulations using the commercially available ANSYS Polyflow software. The major drawbacks of three-dimensional finite-element-method (FEM) simulations are that they require vast computational power and, large quantities of memory, and consume considerable time to create a geometric model created by computer-aided design (CAD) and complete a flow calculation. Consequently, a modified 2.5-dimensional finite volume method, termed network analysis is preferable. The results obtained by network analysis and FEM simulations correlated well. Network analysis provides an efficient alternative to complex FEM software in terms of computing power and memory consumption. Furthermore, typical barrier screw geometries can be parameterized and used for flow calculations without timeconsuming CAD-constructions.

Characterization of WB/SiC Schottky Barrier Diodes Using I-V-T Method

NASA Astrophysics Data System (ADS)

Aldridge, James; Oder, Tom

2009-04-01

The importance of silicon carbide (SiC) semiconductor for high temperature and high power microelectronic device applications has long been established. We have fabricated SiC Schottky barrier diodes using tungsten boride (WB) as the Schottky contact. The diodes were characterized using the current-voltage-temperature method. The sample was mounted on a heated stage and the temperature varied from about 25 ^oC to 300 ^oC at intervals of 25 ^oC. From the Richardson's plot, we obtained an energy barrier height of 0.96 eV and a Richardson's constant of 71.2 AK-1cm-2. Using the modified Richardson's plot, we obtained a barrier height of 1.01 eV. From the variation of the ideality factor and the temperature, we determined a characteristic energy of 0.02 eV to 0.04 eV across the range of the measurement temperature. This implies that thermionic emission is dominant in the low measurement temperature range. Our results confirm the excellent thermal stability of WB/SiC Schottky barrier diodes.

Military Sexual Trauma Among US Servicewomen During Deployment: A Qualitative Study

PubMed Central

Grindlay, Kate; Holt, Kelsey; Manski, Ruth; Grossman, Daniel

2014-01-01

Objectives. We explored qualitatively US servicewomen’s experiences with and perceptions of military sexual trauma (MST), reporting, and related services. Methods. From May 2011 to January 2012, we conducted 22 telephone interviews with US servicewomen deployed overseas between 2002 and 2011. We analyzed data thematically with modified grounded theory methods. Results. Factors identified as contributing to MST included deployment dynamics, military culture, and lack of consequences for perpetrators. Participants attributed low MST reporting to negative reactions and blame from peers and supervisors, concerns about confidentiality, and stigma. Unit cohesion was cited as both a facilitator and a barrier to reporting. Availability and awareness of MST services during deployment varied. Barriers to care seeking were similar to reporting barriers and included confidentiality concerns and stigma. We identified several avenues to address MST, including strengthening consequences for perpetrators. Conclusions. We identified barriers to MST reporting and services. Better understanding of these issues will allow policymakers to improve MST prevention and services. PMID:24328617

Implementation of power barrier option valuation

NASA Astrophysics Data System (ADS)

Cahyani, Agatha C. P.; Sumarti, Novriana

2015-09-01

Options are financial instruments that can be utilized to reduce risk in stock investment. Barrier options are one of the major types of options actively used in financial markets where its life period depends on the path of the underlying stock prices. The features of the barrier option can be used to modify other types of options. In this research, the barrier option will be implemented into power option, so it is called power barrier option. This option is an extension of the vanilla barrier options where the Call payoff being considered is defined as P C =max (STβ-Kβ,0 ) , and the Put payoff being considered is defined as P P =max (Kβ-STβ,0 ) . Here β > 0 and β ≠ 1, K is the strike price of the option, and ST is the price of the underlying stock at time maturity T. In this paper, we generate the prices of stock using binomial method which is adjusted to the power option. In the conclusion, the price of American power barrier option is more expensive than the price of European power barrier option.

Studying the Impact of Modified Saccharides on the Molecular Dynamics and Crystallization Tendencies of Model API Nifedipine.

PubMed

Kaminska, E; Tarnacka, M; Wlodarczyk, P; Jurkiewicz, K; Kolodziejczyk, K; Dulski, M; Haznar-Garbacz, D; Hawelek, L; Kaminski, K; Wlodarczyk, A; Paluch, M

2015-08-03

Molecular dynamics of pure nifedipine and its solid dispersions with modified carbohydrates as well as the crystallization kinetics of active pharmaceutical ingredient (API) above and below the glass transition temperature were studied in detail by means of broadband dielectric spectroscopy (BDS), differential scanning calorimetry (DSC), and X-ray diffraction method. It was found that the activation barrier of crystallization increases in molecular dispersions composed of acetylated disaccharides, whereas it slightly decreases in those consisting of modified monocarbohydrates for the experiments carried out above the glass transition temperature. As shown by molecular dynamics simulations it can be related to the strength, character, and structure of intermolecular interactions between API and saccharides, which vary dependently on the excipient. Long-term physical stability studies showed that, in solid dispersions consisting of acetylated maltose and acetylated sucrose, the crystallization of nifedipine is dramatically slowed down, although it is still observable for a low concentration of excipients. With increasing content of modified carbohydrates, the crystallization of API becomes completely suppressed. This is most likely due to additional barriers relating to the intermolecular interactions and diffusion of nifedipine that must be overcome to trigger the crystallization process.

Effects of Post Annealing on I-V-T Characteristics of (Ni/Au)/Al0.09Ga0.91N Schottky Barrier Diodes

NASA Astrophysics Data System (ADS)

Akkaya, Abdullah; Ayyıldız, Enise

2016-04-01

Post annealing is a simple, effective and suitable method for improving the diode parameters, especially when the used chemically stable substrates like Si, III-N and ternary alloys. In our work, we were applied this method to (Ni/Au)/Al0.09Ga0.91N Schottky Barrier Diodes (SBDs) and investigated by temperature-dependent current-voltage (I-V-T) characteristics at optimum conditions. Optimum annealing temperature was 600°C, which it’s determined with respect to have a highest barrier height value. The temperature-dependent electrical characteristics of the annealed at 600°C (Ni/Au)/Al0.09Ga0.91N SBDs were investigated in the wide temperature range of 95-315K. The diode parameters such as ideality factor (n) and Schottky barrier height (Vb0) were obtained to be strongly temperature dependent. The observed variation in Vb0 and n can be attributed to the spatial barrier inhomogeneities in Schottky barrier height by assuming a triple Gaussian distribution (TGD) of barrier heights (BHs) at 95-145K, 145-230K and 230-315K. The modified Richardson plots and T0 analysis was performed to provide an experimental Richardson constants and bias coefficients of the mean barrier height. Furthermore, the chemical composition of the contacts was examined by the XPS depth profile analysis.

Understanding the modifiable health systems barriers to hypertension management in Malaysia: a multi-method health systems appraisal approach.

PubMed

Risso-Gill, Isabelle; Balabanova, Dina; Majid, Fadhlina; Ng, Kien Keat; Yusoff, Khalid; Mustapha, Feisul; Kuhlbrandt, Charlotte; Nieuwlaat, Robby; Schwalm, J-D; McCready, Tara; Teo, Koon K; Yusuf, Salim; McKee, Martin

2015-07-03

The growing burden of non-communicable diseases in middle-income countries demands models of care that are appropriate to local contexts and acceptable to patients in order to be effective. We describe a multi-method health system appraisal to inform the design of an intervention that will be used in a cluster randomized controlled trial to improve hypertension control in Malaysia. A health systems appraisal was undertaken in the capital, Kuala Lumpur, and poorer-resourced rural sites in Peninsular Malaysia and Sabah. Building on two systematic reviews of barriers to hypertension control, a conceptual framework was developed that guided analysis of survey data, documentary review and semi-structured interviews with key informants, health professionals and patients. The analysis followed the patients as they move through the health system, exploring the main modifiable system-level barriers to effective hypertension management, and seeking to explain obstacles to improved access and health outcomes. The study highlighted the need for the proposed intervention to take account of how Malaysian patients seek treatment in both the public and private sectors, and from western and various traditional practitioners, with many patients choosing to seek care across different services. Patients typically choose private care if they can afford to, while others attend heavily subsidised public clinics. Public hypertension clinics are often overwhelmed by numbers of patients attending, so health workers have little time to engage effectively with patients. Treatment adherence is poor, with a widespread belief, stemming from concepts of traditional medicine, that hypertension is a transient disturbance rather than a permanent asymptomatic condition. Drug supplies can be erratic in rural areas. Hypertension awareness and education material are limited, and what exist are poorly developed and ineffective. Despite having a relatively well funded health system offering good access to care, Malaysia's health system still has significant barriers to effective hypertension management. The study uncovered major patient-related barriers to the detection and control of hypertension which will have an impact on the design and implementation of any hypertension intervention. Appropriate models of care must take account of the patient modifiable health systems barriers if they are to have any realistic chance of success; these findings are relevant to many countries seeking to effectively control hypertension despite resource constraints.

In silico direct folding of thrombin-binding aptamer G-quadruplex at all-atom level

PubMed Central

Yang, Changwon; Kulkarni, Mandar; Lim, Manho

2017-01-01

Abstract The reversible folding of the thrombin-binding DNA aptamer G-quadruplexes (GQs) (TBA-15) starting from fully unfolded states was demonstrated using a prolonged time scale (10–12 μs) parallel tempering metadynamics (PTMetaD) simulation method in conjunction with a modified version of the AMBER bsc1 force field. For unbiased descriptions of the folding free energy landscape of TBA-15, this force field was minimally modified. From this direct folding simulation using the modified bsc1 force field, reasonably converged free energy landscapes were obtained in K+-rich aqueous solution (150 mM), providing detailed atomistic pictures of GQ folding mechanisms for TBA-15. This study found that the TBA folding occurred via multiple folding pathways with two major free energy barriers of 13 and 15 kcal/mol in the presence of several intermediate states of G-triplex variants. The early formation of these intermediates was associated with a single K+ ion capturing. Interestingly, these intermediate states appear to undergo facile transitions among themselves through relatively small energy barriers. PMID:29112755

A fast method to produce strong NFC films as a platform for barrier and functional materials.

PubMed

Osterberg, Monika; Vartiainen, Jari; Lucenius, Jessica; Hippi, Ulla; Seppälä, Jukka; Serimaa, Ritva; Laine, Janne

2013-06-12

In this study, we present a rapid method to prepare robust, solvent-resistant, nanofibrillated cellulose (NFC) films that can be further surface-modified for functionality. The oxygen, water vapor, and grease barrier properties of the films were measured, and in addition, mechanical properties in the dry and wet state and solvent resistance were evaluated. The pure unmodified NFC films were good barriers for oxygen gas and grease. At a relative humidity below 65%, oxygen permeability of the pure and unmodified NFC films was below 0.6 cm(3) μm m(-2) d(-1) kPa(-1), and no grease penetrated the film. However, the largest advantage of these films was their resistance to various solvents, such as water, methanol, toluene, and dimethylacetamide. Although they absorbed a substantial amount of solvent, the films could still be handled after 24 h of solvent soaking. Hot-pressing was introduced as a convenient method to not only increase the drying speed of the films but also enhance the robustness of the films. The wet strength of the films increased due to the pressing. Thus, they can be chemically or physically modified through adsorption or direct chemical reaction in both aqueous and organic solvents. Through these modifications, the properties of the film can be enhanced, introducing, for example, functionality, hydrophobicity, or bioactivity. Herein, a simple method using surface coating with wax to improve hydrophobicity and oxygen barrier properties at very high humidity is described. Through this modification, the oxygen permeability decreased further and was below 17 cm(3) μm m(-2) d(-1) kPa(-1) even at 97.4% RH, and the water vapor transmission rate decreased from 600 to 40 g/m(2) day. The wax treatment did not deteriorate the dry strength of the film. Possible reasons for the unique properties are discussed. The developed robust NFC films can be used as a generic, environmentally sustainable platform for functional materials.

Uptake Mechanism of ApoE-Modified Nanoparticles on Brain Capillary Endothelial Cells as a Blood-Brain Barrier Model

PubMed Central

Wagner, Sylvia; Zensi, Anja; Wien, Sascha L.; Tschickardt, Sabrina E.; Maier, Wladislaw; Vogel, Tikva; Worek, Franz; Pietrzik, Claus U.; Kreuter, Jörg; von Briesen, Hagen

2012-01-01

Background The blood-brain barrier (BBB) represents an insurmountable obstacle for most drugs thus obstructing an effective treatment of many brain diseases. One solution for overcoming this barrier is a transport by binding of these drugs to surface-modified nanoparticles. Especially apolipoprotein E (ApoE) appears to play a major role in the nanoparticle-mediated drug transport across the BBB. However, at present the underlying mechanism is incompletely understood. Methodology/Principal Findings In this study, the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells was investigated to differentiate between active and passive uptake mechanism by flow cytometry and confocal laser scanning microscopy. Furthermore, different in vitro co-incubation experiments were performed with competing ligands of the respective receptor. Conclusions/Significance This study confirms an active endocytotic uptake mechanism and shows the involvement of low density lipoprotein receptor family members, notably the low density lipoprotein receptor related protein, on the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells. This knowledge of the uptake mechanism of ApoE-modified nanoparticles enables future developments to rationally create very specific and effective carriers to overcome the blood-brain barrier. PMID:22396775

Uptake mechanism of ApoE-modified nanoparticles on brain capillary endothelial cells as a blood-brain barrier model.

PubMed

Wagner, Sylvia; Zensi, Anja; Wien, Sascha L; Tschickardt, Sabrina E; Maier, Wladislaw; Vogel, Tikva; Worek, Franz; Pietrzik, Claus U; Kreuter, Jörg; von Briesen, Hagen

2012-01-01

The blood-brain barrier (BBB) represents an insurmountable obstacle for most drugs thus obstructing an effective treatment of many brain diseases. One solution for overcoming this barrier is a transport by binding of these drugs to surface-modified nanoparticles. Especially apolipoprotein E (ApoE) appears to play a major role in the nanoparticle-mediated drug transport across the BBB. However, at present the underlying mechanism is incompletely understood. In this study, the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells was investigated to differentiate between active and passive uptake mechanism by flow cytometry and confocal laser scanning microscopy. Furthermore, different in vitro co-incubation experiments were performed with competing ligands of the respective receptor. This study confirms an active endocytotic uptake mechanism and shows the involvement of low density lipoprotein receptor family members, notably the low density lipoprotein receptor related protein, on the uptake of the ApoE-modified nanoparticles into the brain capillary endothelial cells. This knowledge of the uptake mechanism of ApoE-modified nanoparticles enables future developments to rationally create very specific and effective carriers to overcome the blood-brain barrier.

Implementing clinical governance in Isfahan hospitals: Barriers and solutions, 2014.

PubMed

Ferdosi, Masoud; Ziyari, Farhad Bahman; Ollahi, Mehran Nemat; Salmani, Amaneh Rahim; Niknam, Noureddin

2016-01-01

In the new approach, all health care providers have been obligated to maintain and improve the quality and have been accountable for it. One of the ways is the implementation of clinical governance (CG). More accurate understanding of its challenges can help to improve its performance. In this study, barriers of CG implementation are investigated from the perspective of the hospitals involved. Besides, some solutions are suggested based on stakeholders' opinions. This study used combined method (qualitative content analysis and questionnaire) in hospitals affiliated to Isfahan University of Medical Sciences in 2014. First, experts, and stakeholders talked about CG implementation obstacles in a semi-structured interview. Interviews were confirmed by the interviewee (double check). After analyzing the interviews using reduction coding the questionnaire was drawn up. The questionnaire "validity was confirmed by Cronbach's alpha (0/891)" and its reliability was obtained using experts confirmation. Data analyzing was performed using SPSS (18) software. According to results staffing and management factors were the main obstacles. After them, were factors related to organizational culture, infrastructure elements, information, sociocultural and then process factors. The learning barriers were in final rank. Thirty-four solutions was proposed by experts and divided into subset of eight major barriers. Most solutions were offered on modifying processes and minimal solutions about modifying of organizational culture, sociocultural, and educational factors. Removing the obstacles, especially management and human resource factors can be effective by facilitating and accelerating CG. Furthermore, use of experts and stakeholders opinions can help to remove CG barriers.

Optimized surface topography of thermoplastics blends modified by graphene

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

Joshi, Girish M., E-mail: varadgm@gmail.com, E-mail: girish.joshi@vit.ac.in; Sharma, Ajay; Pandey, Mayank

2016-05-23

Polyacrilonitrile (PAN)/ Polyvinylfloride (PVDF) blends were modified by loading the graphene (0.5 to 1.5 wt %). The presence of graphene reveals the interesting surface properties. The decrease in surface roughness as function of graphene loading was confirmed by the topographic method of recording (two and three dimensional images) with atomic force microscope (AFM). The blends become smoother in nature due to occupied smaller surface area of graphene. This property may be useful for several applications in the marine, naval, nuclear domain and engineering applications as barrier medium.

Permeable reactive barrier of surface hydrophobic granular activated carbon coupled with elemental iron for the removal of 2,4-dichlorophenol in water.

PubMed

Yang, Ji; Cao, Limei; Guo, Rui; Jia, Jinping

2010-12-15

Granular activated carbon was modified with dimethyl dichlorosilane to improve its surface hydrophobicity, and therefore to improve the performance of permeable reactive barrier constructed with the modified granular activated carbon and elemental iron. X-ray photoelectron spectroscopy shows that the surface silicon concentration of the modified granular activated carbon is higher than that of the original one, leading to the increased surface hydrophobicity. Although the specific surface area decreased from 895 to 835 m(2)g(-1), the modified granular activated carbon could adsorb 20% more 2,4-dichlorophenol than the original one did in water. It is also proven that the permeable reactive barrier with the modified granular activated carbon is more efficient at 2,4-dichlorophenol dechlorination, in which process 2,4-dichlorophenol is transformed to 2-chlorophenol or 4-chlorophenol then to phenol, or to phenol directly. Copyright © 2010 Elsevier B.V. All rights reserved.

Movers, Shakers, & Everyone in Between: Faculty Personas Surrounding Active Learning in the Undergraduate STEM Classroom

ERIC Educational Resources Information Center

Guy, Batsheva R.

2017-01-01

This qualitative study explores the attitudes that STEM (Science, Technology, Engineering, and Mathematics) faculty have about active learning (AL), the barriers that STEM faculty face when implementing AL, and what would encourage STEM faculty to use AL. Data was gathered using a modified Group-Level Assessment (GLA), a participatory method meant…

Numerical investigation of dielectric barrier discharges

NASA Astrophysics Data System (ADS)

Li, Jing

1997-12-01

A dielectric barrier discharge (DBD) is a transient discharge occurring between two electrodes in coaxial or planar arrangements separated by one or two layers of dielectric material. The charge accumulated on the dielectric barrier generates a field in a direction opposite to the applied field. The discharge is quenched before an arc is formed. It is one of the few non-thermal discharges that operates at atmospheric pressure and has the potential for use in pollution control. In this work, a numerical model of the dielectric barrier discharge is developed, along with the numerical approach. Adaptive grids based on the charge distribution is used. A self-consistent method is used to solve for the electric field and charge densities. The Successive Overrelaxation (SOR) method in a non-uniform grid spacing is used to solve the Poisson's equation in the cylindrically-symmetric coordinate. The Flux Corrected Transport (FCT) method is modified to solve the continuity equations in the non-uniform grid spacing. Parametric studies of dielectric barrier discharges are conducted. General characteristics of dielectric barrier discharges in both anode-directed and cathode-directed streamer are studied. Effects of the dielectric capacitance, the applied field, the resistance in external circuit and the type of gases (O2, air, N2) are investigated. We conclude that the SOR method in an adaptive grid spacing for the solution of the Poisson's equation in the cylindrically-symmetric coordinate is convergent and effective. The dielectric capacitance has little effect on the g-factor of radical production, but it determines the strength of the dielectric barrier discharge. The applied field and the type of gases used have a significant role on the current peak, current pulse duration and radical generation efficiency, discharge strength, and microstreamer radius, whereas the external series resistance has very little effect on the streamer properties. The results are helpful in further understanding the ozone generation and pollution control process in a dielectric barrier discharge.

The determination of modified barrier heights in Ti/GaN nano-Schottky diodes at high temperature.

PubMed

Lee, Seung-Yong; Kim, Tae-Hong; Chol, Nam-Kyu; Seong, Han-Kyu; Choi, Heon-Jin; Ahn, Byung-Guk; Lee, Sang-Kwon

2008-10-01

We have investigated the size-effect of the nano-Schottky diodes on the electrical transport properties and the temperature-dependent current transport mechanism in a metal-semiconductor nanowire junction (a Ti/GaN nano-Schottky diode) using current-voltage characterization in the range of 300-423 K. We found that the modified mean Schottky barrier height (SBH) was approximately 0.7 eV with a standard deviation of approximately 0.14 V using a Gaussian distribution model of the barrier heights. The slightly high value of the modified mean SBH (approximately 0.11 eV) compared to the results from the thin-film based Ti/GaN Schottky diodes could be due to an additional oxide layer at the interface between the Ti and GaN nanowires. Moreover, we found that the abnormal behavior of the barrier heights and the ideality factors in a Ti/GaN nano-Schottky diode at a temperature below 423 K could be explained by a combination of the enhancement of the tunneling current and a model with a Gaussian distribution of the barrier heights.

Effects of ultrathin oxides in conducting MIS structures on GaAs

NASA Technical Reports Server (NTRS)

Childs, R. B.; Ruths, J. M.; Sullivan, T. E.; Fonash, S. J.

1978-01-01

Schottky barrier-type GaAs baseline devices (semiconductor surface etched and then immediately metalized) and GaAs conducting metal oxide-semiconductor devices are fabricated and characterized. The baseline surfaces (no purposeful oxide) are prepared by a basic or an acidic etch, while the surface for the MIS devices are prepared by oxidizing after the etch step. The metallizations used are thin-film Au, Ag, Pd, and Al. It is shown that the introduction of purposeful oxide into these Schottky barrier-type structures examined on n-type GaAs modifies the barrier formation, and that thin interfacial layers can modify barrier formation through trapping and perhaps chemical reactions. For Au- and Pd-devices, enhanced photovoltaic performance of the MIS configuration is due to increased barrier height.

Insilico direct folding of thrombin-binding aptamer G-quadruplex at all-atom level.

PubMed

Yang, Changwon; Kulkarni, Mandar; Lim, Manho; Pak, Youngshang

2017-12-15

The reversible folding of the thrombin-binding DNA aptamer G-quadruplexes (GQs) (TBA-15) starting from fully unfolded states was demonstrated using a prolonged time scale (10-12 μs) parallel tempering metadynamics (PTMetaD) simulation method in conjunction with a modified version of the AMBER bsc1 force field. For unbiased descriptions of the folding free energy landscape of TBA-15, this force field was minimally modified. From this direct folding simulation using the modified bsc1 force field, reasonably converged free energy landscapes were obtained in K+-rich aqueous solution (150 mM), providing detailed atomistic pictures of GQ folding mechanisms for TBA-15. This study found that the TBA folding occurred via multiple folding pathways with two major free energy barriers of 13 and 15 kcal/mol in the presence of several intermediate states of G-triplex variants. The early formation of these intermediates was associated with a single K+ ion capturing. Interestingly, these intermediate states appear to undergo facile transitions among themselves through relatively small energy barriers. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Geographically weighted regression as a generalized Wombling to detect barriers to gene flow.

PubMed

Diniz-Filho, José Alexandre Felizola; Soares, Thannya Nascimento; de Campos Telles, Mariana Pires

2016-08-01

Barriers to gene flow play an important role in structuring populations, especially in human-modified landscapes, and several methods have been proposed to detect such barriers. However, most applications of these methods require a relative large number of individuals or populations distributed in space, connected by vertices from Delaunay or Gabriel networks. Here we show, using both simulated and empirical data, a new application of geographically weighted regression (GWR) to detect such barriers, modeling the genetic variation as a "local" linear function of geographic coordinates (latitude and longitude). In the GWR, standard regression statistics, such as R(2) and slopes, are estimated for each sampling unit and thus are mapped. Peaks in these local statistics are then expected close to the barriers if genetic discontinuities exist, capturing a higher rate of population differentiation among neighboring populations. Isolation-by-Distance simulations on a longitudinally warped lattice revealed that higher local slopes from GWR coincide with the barrier detected with Monmonier algorithm. Even with a relatively small effect of the barrier, the power of local GWR in detecting the east-west barriers was higher than 95 %. We also analyzed empirical data of genetic differentiation among tree populations of Dipteryx alata and Eugenia dysenterica Brazilian Cerrado. GWR was applied to the principal coordinate of the pairwise FST matrix based on microsatellite loci. In both simulated and empirical data, the GWR results were consistent with discontinuities detected by Monmonier algorithm, as well as with previous explanations for the spatial patterns of genetic differentiation for the two species. Our analyses reveal how this new application of GWR can viewed as a generalized Wombling in a continuous space and be a useful approach to detect barriers and discontinuities to gene flow.

Transport in a magnetic field modulated graphene superlattice.

PubMed

Li, Yu-Xian

2010-01-13

Using the transfer matrix method, we study the transport properties through a magnetic field modulated graphene superlattice. It is found that the electrostatic barrier, the magnetic vector potential, and the number of wells in a superlattice modify the transmission remarkably. The angular dependent transmission is blocked by the magnetic vector potential because of the appearance of the evanescent states at certain incident angles, and the region of Klein tunneling shifts to the left. The angularly averaged conductivities exhibit oscillatory behavior. The magnitude and period of oscillation depend sensitively on the height of the electrostatic barrier, the number of wells, and the strength of the modulated magnetic field.

Use of Edible Laminate Layers in Intermediate Moisture Food Rations to Inhibit Moisture Migration

DTIC Science & Technology

2016-04-29

methylcellulose, propylene glycol, citric acid, modified starch , white beeswax Water resistant coating on one side Watson, Inc. Dual-sided HPMC moisture...barrier film Hydroxypropyl methylcellulose, propylene glycol, citric acid, modified starch , white beeswax Water resistant coating on both sides...Moisture Barrier (BWMB) film #1 Pullulan*, beeswax, glycerin, propylene glycol, starch , polysorbate 80 Water soluble Watson, Inc. Pullulan BWMB film

Barriers to and Facilitators of Research Utilization: A Survey of Registered Nurses in China

PubMed Central

Wang, Li-Ping; Jiang, Xiao-Lian; Wang, Lei; Wang, Guo-Rong; Bai, Yang-Jing

2013-01-01

Aims This survey aims to describe the perception of barriers to and facilitators of research utilization by registered nurses in Sichuan province, China, and to explore the factors influencing the perceptions of the barriers to and facilitators of research utilization. Methods A cross sectional survey design and a double cluster sampling method were adopted. A total of 590 registered nurses from 3 tertiary level hospitals in Sichuan province, China, were recruited in a period from September 2006 to January 2007. A modified BARRUERS Scale and a Facilitators Scale were used. Data were analyzed with descriptive statistics, rank transformation test, and multiple linear regression. Results Barriers related to the setting subscale were more influential than barriers related to other subscales. The lack of authority was ranked as the top greatest barrier (15.7%), followed by the lack of time (13.4%) and language barrier (15.0%). Additional barriers identified were the reluctance of patients to research utilization, the lack of funding, and the lack of legal protection. The top three greatest facilitators were enhancing managerial support (36.9%), advancing education to increase knowledge base (21.1%), and increasing time for reviewing and implementing (17.5%), while cooperation of patients to research utilization, establishing a panel to evaluate researches, and funding were listed as additional facilitators. Hospital, educational background, research experience, and knowledge on evidence-based nursing were the factors influencing perceptions of the barriers and facilitators. Conclusions Nurses in China are facing a number of significant barriers in research utilization. Enhancing managerial support might be the most promising facilitator, given Chinese traditional culture and existing health care system. Hospital, educational background, research experience and knowledge on evidence-based nursing should be taken into account to promote research utilization. The BARRIERS Scale should consider funding and involvement of patients in research utilization. PMID:24312380

Ultrashort dark solitons interactions and nonlinear tunneling in the modified nonlinear Schrödinger equation with variable coefficient

NASA Astrophysics Data System (ADS)

Musammil, N. M.; Porsezian, K.; Nithyanandan, K.; Subha, P. A.; Tchofo Dinda, P.

2017-09-01

We present the study of the dark soliton dynamics in an inhomogeneous fiber by means of a variable coefficient modified nonlinear Schrödinger equation (Vc-MNLSE) with distributed dispersion, self-phase modulation, self-steepening and linear gain/loss. The ultrashort dark soliton pulse evolution and interaction is studied by using the Hirota bilinear (HB) method. In particular, we give much insight into the effect of self-steepening (SS) on the dark soliton dynamics. The study reveals a shock wave formation, as a major effect of SS. Numerically, we study the dark soliton propagation in the continuous wave background, and the stability of the soliton solution is tested in the presence of photon noise. The elastic collision behaviors of the dark solitons are discussed by the asymptotic analysis. On the other hand, considering the nonlinear tunneling of dark soliton through barrier/well, we find that the tunneling of the dark soliton depends on the height of the barrier and the amplitude of the soliton. The intensity of the tunneling soliton either forms a peak or valley and retains its shape after the tunneling. For the case of exponential background, the soliton tends to compress after tunneling through the barrier/well.

Improved performance of In0.83Ga0.17As/InP photodetectors through modifying the position of In0.66Ga0.34As/InAs superlattice electron barrier

NASA Astrophysics Data System (ADS)

Shi, Yan-hui; Zhang, Yong-gang; Ma, Ying-jie; Gu, Yi; Chen, Xing-you; Gong, Qian; Du, Ben; Zhang, Jian; Zhu, Yi

2018-03-01

The performance of wavelength extended In0.83Ga0.17As/InP photodetectors has been improved notably through modifying the position of electron barriers in absorption layer. In order to fully utilize the diffusion component of the photocurrent, the In0.66Ga0.34As/InAs superlattice electron barrier is moved to the edge of the depletion region. Enhanced peak photo responsivity up to 0.84 A/W is realized, which raises 24% compared to that of a reference detector with the superlattice barrier in the middle of the absorber. The dark current slightly increases by 25% at room temperature while decreases by more than an order of magnitude at 150 K, resulting in about 10% or more than twofold improvements for the detectivity, respectively. The results suggest that optimized barrier position is a necessity for barrier-type photodetectors to achieve better performances.

Self-learning kinetic Monte Carlo simulations of Al diffusion in Mg

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

Nandipati, Giridhar; Govind, Niranjan; Andersen, Amity

2016-03-16

Atomistic on-lattice self-learning kinetic Monte Carlo (SLKMC) method was used to examine the vacancy-mediated diffusion of an Al atom in pure hcp Mg. Local atomic environment dependent activation barriers for vacancy-atom exchange processes were calculated on-the-fly using climbing image nudged-elastic band method (CI-NEB) and using a Mg-Al binary modified embedded-atom method (MEAM) interatomic potential. Diffusivities of vacancy and Al atom in pure Mg were obtained from SLKMC simulations and are compared with values available in the literature that are obtained from experiments and first-principle calculations. Al Diffusivities obtained from SLKMC simulations are lower, due to larger activation barriers and lowermore » diffusivity prefactors, than those available in the literature but have same order of magnitude. We present all vacancy-Mg and vacancy-Al atom exchange processes and their activation barriers that were identified in SLKMC simulations. We will describe a simple mapping scheme to map a hcp lattice on to a simple cubic lattice that would enable hcp lattices to be simulated in an on-lattice KMC framework. We also present the pattern recognition scheme used in SLKMC simulations.« less

Correlates of motivation to quit smoking among alcohol dependent patients in residential treatment

PubMed Central

Martin, Rosemarie A.; Rohsenow, Damaris J.; MacKinnon, Selene Varney; Abrams, David B.; Monti, Peter M.

2006-01-01

Substance use and smoking co-occur at high rates and substance abusers smoke more and have greater difficulty quitting smoking compared to the general population. Methods of increasing smoking cessation among alcoholics are needed to improve their health. This study investigated predictors of motivation to quit smoking among patients early in residential treatment for substance abuse. The 198 alcohol dependent patients were participating is a larger smoking study at an inner-city residential substance abuse treatment program. Motivation was measured by the Contemplation Ladder. A hierarchical multiple regression was conducted to assess whether perceived barriers to smoking cessation and self-efficacy about quitting were associated with motivation to quit smoking independent of the influence of degree of tobacco involvement, substance use, and comorbid depressive symptoms. Motivation was higher with longer previous smoking abstinence, fewer barriers to quitting, and greater self-efficacy but was not influenced by smoking rate, dependence, or gender. While the combination of alcohol and drug use, alcohol and drug problem severity, and depressive symptoms predicted motivation, no one of these variables was significant. Since barriers to change and self-efficacy are potentially modifiable in treatment, these could be salient targets for intervention efforts. This could be integrated into treatment by assessing barriers and providing corrective information about consequences and methods of overcoming barriers and by providing coping skills to increase confidence in one’s ability to quit smoking. PMID:16314049

Enhanced permeability of blood-brain barrier and targeting function of brain via borneol-modified chemically solid lipid nanoparticle.

PubMed

Song, Hui; Wei, Man; Zhang, Nan; Li, He; Tan, Xiaochuan; Zhang, Yujia; Zheng, Wensheng

2018-01-01

The incidence of central nervous system disease has increased in recent years. However, the transportation of drug is restricted by the blood-brain barrier, contributing to the poor therapeutic effect in the brain. Therefore, the development of a new brain-targeting drug delivery system has become the hotspot of pharmacy. Borneol, a simple bicyclic monoterpene extracted from Dryobalanops aromatica , can direct drugs to the upper body parts according to the theory of traditional Chinese medicine. Dioleoyl phosphoethanolamine (DOPE) was chemically modified by borneol as one of the lipid materials of solid lipid nanoparticle (SLN) in the present study. The borneol-modified chemically solid lipid nanoparticle (BO-SLN/CM), borneol-modified physically solid lipid nanoparticle (BO-SLN/PM), and SLN have similar diameter (of about 87 nm) and morphological characteristics. However, BO-SLN/CM has a lower cytotoxicity, higher cell uptake, and better blood-brain barrier permeability compared with BO-SLN/PM and SLN. BO-SLN/CM has a remarkable targeting function to the brain, while BO-SLN/ PM and SLNs are concentrated at the lung. The present study provides an excellent drug delivery carrier, BO-SLN/CM, having the application potential of targeting to the brain and permeating to the blood-brain barrier.

Ultralow-power complementary metal-oxide-semiconductor inverters constructed on Schottky barrier modified nanowire metal-oxide-semiconductor field-effect-transistors.

PubMed

Ma, R M; Peng, R M; Wen, X N; Dai, L; Liu, C; Sun, T; Xu, W J; Qin, G G

2010-10-01

We show that the threshold voltages of both n- and p-channel metal-oxide-semiconductor field-effect-transistors (MOSFETs) can be lowered to close to zero by adding extra Schottky contacts on top of nanowires (NWs). Novel complementary metal-oxide-semiconductor (CMOS) inverters are constructed on these Schottky barrier modified n- and p-channel NW MOSFETs. Based on the high performances of the modified n- and p-channel MOSFETs, especially the low threshold voltages, the as-fabricated CMOS inverters have low operating voltage, high voltage gain, and ultra-low static power dissipation.

Fission properties of Po isotopes in different macroscopic-microscopic models

NASA Astrophysics Data System (ADS)

Bartel, J.; Pomorski, K.; Nerlo-Pomorska, B.; Schmitt, Ch

2015-11-01

Fission-barrier heights of nuclei in the Po isotopic chain are investigated in several macroscopic-microscopic models. Using the Yukawa-folded single-particle potential, the Lublin-Strasbourg drop (LSD) model, the Strutinsky shell-correction method to yield the shell corrections and the BCS theory for the pairing contributions, fission-barrier heights are calculated and found in quite good agreement with the experimental data. This turns out, however, to be only the case when the underlying macroscopic, liquid-drop (LD) type, theory is well chosen. Together with the LSD approach, different LD parametrizations proposed by Moretto et al are tested. Four deformation parameters describing respectively elongation, neck-formation, reflectional-asymmetric, and non-axiality of the nuclear shape thus defining the so called modified Funny Hills shape parametrization are used in the calculation. The present study clearly demonstrates that nuclear fission-barrier heights constitute a challenging and selective tool to discern between such different macroscopic approaches.

An Investigation of the Effects of Self-Assembled Monolayers on Protein Crystallisation

PubMed Central

Zhang, Chen-Yan; Shen, He-Fang; Wang, Qian-Jin; Guo, Yun-Zhu; He, Jin; Cao, Hui-Ling; Liu, Yong-Ming; Shang, Peng; Yin, Da-Chuan

2013-01-01

Most protein crystallisation begins from heterogeneous nucleation; in practice, crystallisation typically occurs in the presence of a solid surface in the solution. The solid surface provides a nucleation site such that the energy barrier for nucleation is lower on the surface than in the bulk solution. Different types of solid surfaces exhibit different surface energies, and the nucleation barriers depend on the characteristics of the solid surfaces. Therefore, treatment of the solid surface may alter the surface properties to increase the chance to obtain protein crystals. In this paper, we propose a method to modify the glass cover slip using a self-assembled monolayer (SAM) of functional groups (methyl, sulfydryl and amino), and we investigated the effect of each SAM on protein crystallisation. The results indicated that both crystallisation success rate in a reproducibility study, and crystallisation hits in a crystallisation screening study, were increased using the SAMs, among which, the methyl-modified SAM demonstrated the most significant improvement. These results illustrated that directly modifying the crystallisation plates or glass cover slips to create surfaces that favour heterogeneous nucleation can be potentially useful in practical protein crystallisation, and the utilisation of a SAM containing a functional group can be considered a promising technique for the treatment of the surfaces that will directly contact the crystallisation solution. PMID:23749116

Negotiation of intracellular membrane barriers by TAT-modified gold nanoparticles.

PubMed

Krpetić, Zeljka; Saleemi, Samia; Prior, Ian A; Sée, Violaine; Qureshi, Rumana; Brust, Mathias

2011-06-28

This paper contributes to the debate on how nanosized objects negotiate membrane barriers inside biological cells. The uptake of peptide-modified gold nanoparticles by HeLa cells has been quantified using atomic emission spectroscopy. The TAT peptide from the HIV virus was singled out as a particularly effective promoter of cellular uptake. The evolution of the intracellular distribution of TAT-modified gold nanoparticles with time has been studied in detail by TEM and systematic image analysis. An unusual trend of particles disappearing from the cytosol and the nucleus and accumulating massively in vesicular bodies was observed. Subsequent release of the particles, both by membrane rupture and by direct transfer across the membrane boundary, was frequently found. Ultimately, near total clearing of particles from the cells occurred. This work provides support for the hypothesis that cell-penetrating peptides can enable small objects to negotiate membrane barriers also in the absence of dedicated transport mechanisms.

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

Chaiko, David J.; Leyva, Argentina A.

The invention provides methods for making clay/wax nanocomposites and coatings and films of same with improved chemical resistance and gas barrier properties. The invention further provides methods for making and using emulsions of such clay/wax nanocomposites. Typically, an organophillic clay is combined with a wax or wax/polymer blend such that the cohesion energy of the clay matches that of the wax or wax/polymer blend. Suitable organophilic clays include mica and phyllosilicates that have been surface-treated with edge or edge and surface modifying agents. The resulting nanocomposites have applications as industrial coatings and in protective packaging.

Barriers, benefits and behaviors related to breakfast consumption among rural adolescents

PubMed Central

Shanafelt, Amy; Wang, Qi; Leduc, Robert; Nanney, Marilyn S.

2015-01-01

Background We sought to determine if perceived barriers, benefits, and modifiable behaviors support or interfere with breakfast consumption in a racially and economically diverse rural high school population. Methods The participants were 832 Minnesota adolescents from 16 rural high schools. We used baseline data from a group randomized trial aimed at increasing school breakfast participation through policy and environmental-level school changes. Students completed an online survey asking about demographics, breakfast eating behaviors, and the barriers and benefits of eating as it relates to school performance. Bivariate and multivariate logistic regression, accounting for clustering by school, was performed using SAS. Each scale was modeled independently. Results Participants were 9th and 10th grade students, 36% free/reduced price lunch (FRL), 30% non-white and 55% female. Breakfast skippers compared to non-breakfast skippers reported fewer school related benefits and beliefs and more barriers to eating breakfast (p < .01). Adjusted models revealed students reported more positive beliefs (OR= 0.78, 95%CI=0.73-0.83), more benefits (OR=0.95, 95% CI=0.93-0.97) and fewer barriers (OR=0.85, 95%CI=0.82-0.87) and were less likely to skip breakfast. Conclusions Future intervention research should focus on alleviating barriers and enhancing education around the school related benefits of eating breakfast. PMID:26830505

Anticorrosion efficiency of ultrasonically deposited silica coatings on titanium

NASA Astrophysics Data System (ADS)

Ertaş, Fatma Sinem; Kaş, Recep; Mikó, Annamária; Birer, Özgür

2013-07-01

We utilized high intensity ultrasound to prepare coatings of silica and organically modified silica composed of multiple layers of densely packed nanoparticles. Ultrasound was used to collide nanoparticles onto an activated titanium surface with high speed. Large areas could be homogeneously coated by this method. These coatings were characterized by spectroscopy and microscopy methods and the anticorrosion efficiency in NaCl solution was evaluated by electrochemical measurements. The results indicated that the composite coatings provided good quality barrier layer on bare titanium and decreased the anodic corrosion rate. It was found that increase in the organic content of the coating shifted the passivation potential towards more positive direction. The comparison of the impedance results recorded at the corrosion potential pointed out that in each case a good quality barrier layer was formed on the titanium surface. The outstanding corrosion resistance of the composite coatings with only ~200 nm thickness shows that ultrasound assisted deposition can be a competitive method to obtain corrosion protective layers.

Adsorption-oxidation of hydrogen sulfide on Fe/walnut-shell activated carbon surface modified by NH3-plasma.

PubMed

Ning, Ping; Liu, Sijian; Wang, Chi; Li, Kai; Sun, Xin; Tang, Lihong; Liu, Gui

2018-02-01

Walnut-shell activated carbon (WSAC) supported ferric oxide was modified by non-thermal plasma (NTP), and the removal efficiency for hydrogen sulfide over Fe/WSAC modified by dielectric barrier discharge (DBD) was significantly promoted. The sample modified for 10min and 6.8kV output (30V input voltage) maintained 100% H 2 S conversion over a long reaction time of 390min. The surface properties of adsorbents modified by NTP under different conditions were evaluated by the methods of X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis and in-situ Fourier transform infrared spectroscopy (FTIR), to help understand the effect of the NTP treatment. NTP treatment enhanced the adsorption capacity of Fe/WSAC, which could due to the formation of micro-pores with sizes of 0.4, 0.5 and 0.75nm. XPS revealed that chemisorbed oxygen changed into lattice oxygen after NTP treatment, and lattice oxygen is beneficial for H 2 S oxidation. From the in-situ FTIR result, transformation of the reaction path on Fe/WSAC was observed after NTP modification. The research results indicate that NTP is an effective method to improve the surface properties of the Fe/WSAC catalyst for H 2 S adsorption-oxidation. Copyright © 2017. Published by Elsevier B.V.

Gender-Related Barriers and Delays in Accessing Tuberculosis Diagnostic and Treatment Services: A Systematic Review of Qualitative Studies

PubMed Central

Akande, Tokunbo; Shankar, Anita V.; McIntire, Katherine N.; Gounder, Celine R.; Gupta, Amita; Yang, Wei-Teng

2014-01-01

Background. Tuberculosis (TB) remains a significant global public health problem with known gender-related (male versus female) disparities. We reviewed the qualitative evidence (written/spoken narrative) for gender-related differences limiting TB service access from symptom onset to treatment initiation. Methods. Following a systematic process, we searched 12 electronic databases, included qualitative studies that assessed gender differences in accessing TB diagnostic and treatment services, abstracted data, and assessed study validity. Using a modified “inductive coding” system, we synthesized emergent themes within defined barriers and delays limiting access at the individual and provider/system levels and examined gender-related differences. Results. Among 13,448 studies, 28 studies were included. All were conducted in developing countries and assessed individual-level barriers; 11 (39%) assessed provider/system-level barriers, 18 (64%) surveyed persons with suspected or diagnosed TB, and 7 (25%) exclusively surveyed randomly sampled community members or health care workers. Each barrier affected both genders but had gender-variable nature and impact reflecting sociodemographic themes. Women experienced financial and physical dependence, lower general literacy, and household stigma, whereas men faced work-related financial and physical barriers and community-based stigma. Conclusions. In developing countries, barriers limiting access to TB care have context-specific gender-related differences that can inform integrated interventions to optimize TB services. PMID:24900921

Liposome-based glioma targeted drug delivery enabled by stable peptide ligands.

PubMed

Wei, Xiaoli; Gao, Jie; Zhan, Changyou; Xie, Cao; Chai, Zhilan; Ran, Danni; Ying, Man; Zheng, Ping; Lu, Weiyue

2015-11-28

The treatment of glioma is one of the most challenging tasks in clinic. As an intracranial tumor, glioma exhibits many distinctive characteristics from other tumors. In particular, various barriers including enzymatic barriers in the blood and brain capillary endothelial cells, blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB) rigorously prevent drug and drug delivery systems from reaching the tumor site. To tackle this dilemma, we developed a liposomal formulation to circumvent multiple-barriers by modifying the liposome surface with proteolytically stable peptides, (D)CDX and c(RGDyK). (D)CDX is a D-peptide ligand of nicotine acetylcholine receptors (nAChRs) on the BBB, and c(RGDyK) is a ligand of integrin highly expressed on the BBTB and glioma cells. Lysosomal compartments of brain capillary endothelial cells are implicated in the transcytosis of those liposomes. However, both peptide ligands displayed exceptional stability in lysosomal homogenate, ensuring that intact ligands could exert subsequent exocytosis from brain capillary endothelial cells and glioma targeting. In the cellular uptake studies, dually labeled liposomes could target both brain capillary endothelial cells and tumor cells, effectively traversing the BBB and BBTB monolayers, overcoming enzymatic barrier and targeting three-dimensional tumor spheroids. Its targeting ability to intracranial glioma was further verified in vivo by ex vivo imaging and histological studies. As a result, doxorubicin liposomes modified with both (D)CDX and c(RGDyK) presented better anti-glioma effect with prolonged median survival of nude mice bearing glioma than did unmodified liposomes and liposomes modified with individual peptide ligand. In conclusion, the liposome suggested in the present study could effectively overcome multi-barriers and accomplish glioma targeted drug delivery, validating its potential value in improving the therapeutic efficacy of doxorubicin for glioma. Copyright © 2015 Elsevier B.V. All rights reserved.

Overcoming translational barriers impeding development of Alzheimer's disease modifying therapies.

PubMed

Golde, Todd E

2016-10-01

It has now been ~ 30 years since the Alzheimer's disease (AD) research entered what may be termed the 'molecular era' that began with the identification of the amyloid β protein (Aβ) as the primary component of amyloid within senile plaques and cerebrovascular amyloid and the microtubule-associated protein tau as the primary component of neurofibrillary tangles in the AD brain. These pivotal discoveries and the subsequent genetic, pathological, and modeling studies supporting pivotal roles for tau and Aβ aggregation and accumulation have provided firm rationale for a new generation of AD therapies designed not to just provide symptomatic benefit, but as disease modifying agents that would slow or even reverse the disease course. Indeed, over the last 20 years numerous therapeutic strategies for disease modification have emerged, been preclinically validated, and advanced through various stages of clinical testing. Unfortunately, no therapy has yet to show significant clinical disease modification. In this review, I describe 10 translational barriers to successful disease modification, highlight current efforts addressing some of these barriers, and discuss how the field could focus future efforts to overcome barriers that are not major foci of current research efforts. Seminal discoveries made over the past 25 years have provided firm rationale for a new generation of Alzheimer's disease (AD) therapies designed as disease modifying agents that would slow or even reverse the disease course. Unfortunately, no therapy has yet to show significant clinical disease modification. In this review, I describe 10 translational barriers to successful AD disease modification, highlight current efforts addressing some of these barriers, and discuss how the field could focus future efforts to overcome these barriers. This article is part of the 60th Anniversary special issue. © 2016 International Society for Neurochemistry.

Diffusion Barriers to Increase the Oxidative Life of Overlay Coatings

NASA Technical Reports Server (NTRS)

Nesbitt, James A.; Lei, Jih-Fen

1999-01-01

Currently, most blades and vanes in the hottest section of aero gas turbine engines require some type of coating for oxidation protection. Newly developed single crystal superalloys have the mechanical potential to operate at increasingly higher component temperatures. However, at these elevated temperatures, coating/substrate interdiffusion can shorten the protective life of the coating. Diffusion barriers between overlay coatings and substrates are being examined to extend the protective life of the coating. A previously- developed finite-difference diffusion model has been modified to predict the oxidative life enhancement due to use of a diffusion barrier. The original diffusion model, designated COSIM, simulates Al diffusion in the coating to the growing oxide scale as well as Al diffusion into the substrate. The COSIM model incorporates an oxide growth and spalling model to provide the rate of Al consumption during cyclic oxidation. Coating failure is predicted when the Al concentration at the coating surface drops to a defined critical level. The modified COSIM model predicts the oxidative life of an overlay coating when a diffusion barrier is present eliminating diffusion of Al from the coating into the substrate. Both the original and the modified diffusion models have been used to predict the effectiveness of a diffusion barrier in extending the protective life of a NiCrAl overlay coating undergoing cyclic oxidation at 1100 C.

Interaction of healthcare staff's attitude with barriers to physical activity in hemodialysis patients: A quantitative assessment.

PubMed

Regolisti, Giuseppe; Maggiore, Umberto; Sabatino, Alice; Gandolfini, Ilaria; Pioli, Sarah; Torino, Claudia; Aucella, Filippo; Cupisti, Adamasco; Pistolesi, Valentina; Capitanini, Alessandro; Caloro, Giorgia; Gregorini, Mariacristina; Battaglia, Yuri; Mandreoli, Marcora; Dani, Lucia; Mosconi, Giovanni; Bellizzi, Vincenzo; Di Iorio, Biagio Raffaele; Conti, Paolo; Fiaccadori, Enrico

2018-01-01

In hemodialysis patients, sedentarism is a potentially modifiable mortality risk factor. We explored whether healthcare staff's attitude towards exercise interacts with patient-perceived barriers in modifying the level of physical activity in this population. In this prospective, cross-sectional, multicenter study we recruited 608 adult patients and 330 members of the healthcare staff in 16 hemodialysis units in Italy. We assessed patient-perceived barriers to, and healthcare staff's attitude towards, exercise by specific questionnaires. We fitted multilevel linear models to analyze the relationships of either barriers or staff's attitude, and their interaction, with a measure of patient self-reported physical activity (the Human Activity Profile-Adjusted Activity Score [HAP-AAS]), adjusting for multiple confounders. We also employed latent class analysis to dichotomize patients into those endorsing or not endorsing barriers. Most barriers were negatively associated with the HAP-AAS (adjusted change attributable to a given barrier ranging between -5.1 ["Feeling too old", 95% Confidence Interval: -9.4 to -0.8] and -15.6 ["Ulcers on legs and feet", 95%CI: -24.8 to -6.5]. We found a significant interaction between staff's attitude and barriers (adjusted P values ranging between 0.03 ["I do not believe that it is physician's or nurse's role providing advice on exercise to patients on dialysis"] and 0.001 ["I do not often ask patients about exercise"]). A beneficial effect of a proactive staff's attitude was evident only in patients not endorsing barriers. Barriers and non-proactive staff's attitude reduce physical activity in hemodialysis patients. Patients not endorsing barriers benefit the most from a proactive staff's attitude.

Organically modified low-grade kaolin as a secondary containment material for underground storage tanks.

PubMed

Moon, Chul-Hwan; Lee, Jai-Young; Oh, Byung-Taek; Choi, Sang-Il

2007-08-01

Batch scale reactions were conducted to evaluate the efficacy of modified low-grade kaolin for the treatment of petroleum contaminants. Low-grade kaolin, which has been unvalued as material in the mining process because of its low quality for commercial products, was modified with HDTMA (hexadecyl-trimethylammonium), and its efficiency was compared with that of HDTMA-modified bentonite, which is used as a secondary containment barrier for underground storage tanks. The sorption capacity and hydraulic conductivity of both the HDTMA-modified bentonite and low-grade kaolin were investigated and showed distribution coefficients in the sorption of benzene, toluene, ethylbenzene and xylene ranging between 45.7 and 583.7 and 57.0 and 525.1, respectively. The hydraulic conductivities were 2.53 x 10(-8) and 5.62 x 10(-8) cm/s for the HDTMA-modified bentonite and low-grade kaolin, respectively. These results suggest that HDTMA-modified low-grade kaolin could be used as a hydraulic barrier against advection migration of petroleum contaminants. Simulation of the one-dimensional transport of benzene through a liner made of either one of the compounds was also performed. These results also showed that HDTMA-modified kaolin more effectively retards the transport of benzene.

Glass Bead-based Genetic Transformation:An Efficient Method for Transformation of Thraustochytrid Microorganisms.

PubMed

Adachi, Takumi; Sahara, Takehiko; Okuyama, Hidetoshi; Morita, Naoki

2017-07-01

Here, we describe a new method for genetic transformation of thraustochytrids, well-known producers of polyunsaturated fatty acids (PUFAs) like docosahexaenoic acid, by combining mild glass (zirconia) bead treatment and electroporation. Because the cell wall is a barrier against transfer of exogenous DNA into cells, gentle vortexing of cells with glass beads was performed prior to electroporation for partial cell wall disruption. G418-resistant transformants of thraustochytrid cells (Aurantiochytrium limacinum strain SR21 and thraustochytrid strain 12B) were successfully obtained with good reproducibility. The method reported here is simpler than methods using enzymes to generate spheroplasts and may provide advantages for PUFA production by using genetically modified thraustochytrids.

Mental-Health Conditions, Barriers to Care, and Productivity Loss Among Officers in An Urban Police Department

PubMed Central

Fox, Justin; Desai, Mayur M.; Britten, Karissa; Lucas, Georgina; Luneau, Renee; Rosenthal, Marjorie S.

2014-01-01

Background Police officers are frequently exposed to situations that can negatively impact their mental health. Methods We conducted this study of an urban police department to determine 1) the prevalence of post-traumatic stress disorder (PTSD), depression, and alcohol abuse; 2) patterns of and barriers to mental-health services utilization; and 3) the impact these conditions have on productivity loss. Results Among 150 officers, PTSD (24%), depression (9%), and alcohol abuse (19%) were common. Only 46.7% had ever sought mental-health services; the most commonly cited barriers to accessing services were concerns regarding confidentiality and the potential “negative career impact.” Officers with mental-health conditions had higher productivity loss (5.9% vs 3.4%, P <0.001) at an annual cost of $ 4,489 per officer. Conclusion Mental-health conditions among police officers are common, and costly, yet most officers had never accessed mental-health services; many due to modifiable risk factors. PMID:23155671

The BARRIERS scale -- the barriers to research utilization scale: A systematic review

PubMed Central

2010-01-01

Background A commonly recommended strategy for increasing research use in clinical practice is to identify barriers to change and then tailor interventions to overcome the identified barriers. In nursing, the BARRIERS scale has been used extensively to identify barriers to research utilization. Aim and objectives The aim of this systematic review was to examine the state of knowledge resulting from use of the BARRIERS scale and to make recommendations about future use of the scale. The following objectives were addressed: To examine how the scale has been modified, to examine its psychometric properties, to determine the main barriers (and whether they varied over time and geographic locations), and to identify associations between nurses' reported barriers and reported research use. Methods Medline (1991 to September 2009) and CINHAL (1991 to September 2009) were searched for published research, and ProQuest® digital dissertations were searched for unpublished dissertations using the BARRIERS scale. Inclusion criteria were: studies using the BARRIERS scale in its entirety and where the sample was nurses. Two authors independently assessed the study quality and extracted the data. Descriptive and inferential statistics were used. Results Sixty-three studies were included, with most using a cross-sectional design. Not one study used the scale for tailoring interventions to overcome identified barriers. The main barriers reported were related to the setting, and the presentation of research findings. Overall, identified barriers were consistent over time and across geographic locations, despite varying sample size, response rate, study setting, and assessment of study quality. Few studies reported associations between reported research use and perceptions of barriers to research utilization. Conclusions The BARRIERS scale is a nonspecific tool for identifying general barriers to research utilization. The scale is reliable as reflected in assessments of internal consistency. The validity of the scale, however, is doubtful. There is no evidence that it is a useful tool for planning implementation interventions. We recommend that no further descriptive studies using the BARRIERS scale be undertaken. Barriers need to be measured specific to the particular context of implementation and the intended evidence to be implemented. PMID:20420696

Media campaign effectiveness in promoting a smoking-cessation program.

PubMed

Czarnecki, Karen Davis; Vichinsky, Laura E; Ellis, Jennifer A; Perl, Sarah B

2010-03-01

Little is known about the perceived barriers among smokers who do not utilize phone-based, population-level smoking-cessation services. The purpose of this study was to improve understanding of a media campaign's impact in promoting a phone-based, time-limited smoking-cessation program as measured by smoker awareness of the program, untapped interest in the program, perceived barriers to use of the program, and suggested methods for enhanced outreach. A random telephone survey of New York City smokers (n=1000) was conducted in 2006 in order to assess awareness of, interest in, and barriers to using the 2006 Nicotine Patch Program. Analyses were conducted in 2006 and 2007. The level of program awareness was high (60% overall), although it varied by demographic subgroup. The level of program interest among smokers unaware of the program was also encouragingly high (54%). Analysis of barriers to program use indicates that enrollment may be increased by addressing hesitance about using patches, developing messages for smokers who do not self-identify as smokers, and clarifying application procedures. Specific outreach strategies suggested by smokers include promotion through direct mail and advertising on public transportation. These data suggest that the use of mass media is an effective method for informing smokers about cessation services and that enrollment could be improved by modifying public messages to address barriers as well as expanding outreach to specific demographic groups. Improved outreach to smokers may be feasible using the strategies suggested by smokers in this survey. These findings can aid smoking-cessation services in expanding their reach and impact. Published by Elsevier Inc.

EVALUATION OF FLOORPAN TEARING AND CABLE SPLICES FOR CABLE BARRIER SYSTEMS

DOT National Transportation Integrated Search

2017-05-26

This research effort consisted of two objectives related to components of a prototype cable barrier system. The first objective was to mitigate the potential for vehicle floorpan tearing by modifying the cable guardrail posts. A bogie vehicle was equ...

Creating a Culture of Wellness in Residency.

PubMed

Edmondson, Emma K; Kumar, Anupam A; Smith, Stephanie M

2018-04-17

Despite increased awareness and recognition of the prevalence of physician burnout and the associated risks of depression and suicide, there is a paucity of actionable guidelines for residency programs to mitigate these risks for their residents. In this Invited Commentary, the authors acknowledge that, although there are inherent barriers to resident wellness, there are numerous modifiable barriers that present opportunities for programs to enable culture change and improve resident wellbeing. The authors frame the discussion with a personal narrative written by a resident in their internal medicine program who experienced burnout, depression, and suicidality during his intern year. They aim to inspire residency programs and hospital leadership to identify and intervene upon the modifiable barriers to wellness for residents in their programs in order to shape meaningful cultural change.

A methodology for generating a tailored implementation blueprint: an exemplar from a youth residential setting.

PubMed

Lewis, Cara C; Scott, Kelli; Marriott, Brigid R

2018-05-16

Tailored implementation approaches are touted as more likely to support the integration of evidence-based practices. However, to our knowledge, few methodologies for tailoring implementations exist. This manuscript will apply a model-driven, mixed methods approach to a needs assessment to identify the determinants of practice, and pilot a modified conjoint analysis method to generate an implementation blueprint using a case example of a cognitive behavioral therapy (CBT) implementation in a youth residential center. Our proposed methodology contains five steps to address two goals: (1) identify the determinants of practice and (2) select and match implementation strategies to address the identified determinants (focusing on barriers). Participants in the case example included mental health therapists and operations staff in two programs of Wolverine Human Services. For step 1, the needs assessment, they completed surveys (clinician N = 10; operations staff N = 58; other N = 7) and participated in focus groups (clinician N = 15; operations staff N = 38) guided by the domains of the Framework for Diffusion [1]. For step 2, the research team conducted mixed methods analyses following the QUAN + QUAL structure for the purpose of convergence and expansion in a connecting process, revealing 76 unique barriers. Step 3 consisted of a modified conjoint analysis. For step 3a, agency administrators prioritized the identified barriers according to feasibility and importance. For step 3b, strategies were selected from a published compilation and rated for feasibility and likelihood of impacting CBT fidelity. For step 4, sociometric surveys informed implementation team member selection and a meeting was held to identify officers and clarify goals and responsibilities. For step 5, blueprints for each of pre-implementation, implementation, and sustainment phases were generated. Forty-five unique strategies were prioritized across the 5 years and three phases representing all nine categories. Our novel methodology offers a relatively low burden collaborative approach to generating a plan for implementation that leverages advances in implementation science including measurement, models, strategy compilations, and methods from other fields.

Development of antibody-modified chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier as a strategy for inhibiting HIV replication in astrocytes.

PubMed

Gu, Jijin; Al-Bayati, Karam; Ho, Emmanuel A

2017-08-01

RNA interference (RNAi)-mediated gene silencing offers a novel treatment and prevention strategy for human immunodeficiency virus (HIV) infection. HIV was found to infect and replicate in human brain cells and can cause neuroinfections and neurological deterioration. We designed dual-antibody-modified chitosan/small interfering RNA (siRNA) nanoparticles to deliver siRNA across the blood-brain barrier (BBB) targeting HIV-infected brain astrocytes as a strategy for inhibiting HIV replication. We hypothesized that transferrin antibody and bradykinin B2 antibody could specifically bind to the transferrin receptor (TfR) and bradykinin B2 receptor (B2R), respectively, and deliver siRNA across the BBB into astrocytes as potential targeting ligands. In this study, chitosan nanoparticles (CS-NPs) were prepared by a complex coacervation method in the presence of siRNA, and antibody was chemically conjugated to the nanoparticles. The antibody-modified chitosan nanoparticles (Ab-CS-NPs) were spherical in shape, with an average particle size of 235.7 ± 10.2 nm and a zeta potential of 22.88 ± 1.78 mV. The therapeutic potential of the nanoparticles was evaluated based on their cellular uptake and gene silencing efficiency. Cellular accumulation and gene silencing efficiency of Ab-CS-NPs in astrocytes were significantly improved compared to non-modified CS-NPs and single-antibody-modified CS-NPs. These results suggest that the combination of anti-Tf antibody and anti-B2 antibody significantly increased the knockdown effect of siRNA-loaded nanoparticles. Thus, antibody-mediated dual-targeting nanoparticles are an efficient and promising delivery strategy for inhibiting HIV replication in astrocytes. Graphical abstract Graphic representation of dual-antibody-conjugated chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier (BBB) for inhibiting HIV replication in astrocytes. a Nanoparticle delivery to the BBB and penetration. b TfR-mediated transcytosis of nanoparticles across the epithelial cells. c B2R-mediated endocytosis of nanoparticles in astrocytes. d The molecular interactions between HIV-1 Tat protein and Cyclin T1 and Tip110 cellular proteins. e A schematic representation of chitosan nanoparticles with its components. RNAPII RNA polymerase II, TAR transactivation response RNA element, LTR long terminal repeat, Ab antibody, CS chitosan, TPP tripolyphosphate.

Evaluation of the effects of hyaluronic acid-carboxymethyl cellulose barrier on ovarian tumor progression

PubMed Central

2014-01-01

Background Hyaluronic acid is a prognostic factor in ovarian cancers. It is also a component of Hyaluronic Acid-Carboxymethyl Cellulose (HA-CMC) barrier, an anti-adhesion membrane widely used during abdominal surgeries in particular for ovarian carcinosis. 70% of patients who undergo ovarian surgery will relapse due to the persistence of cancer cells. This study’s objective was to determine the oncological risk from use of this material, in the presence of residual disease, despite the benefit gained by it decreasing post-surgical adhesions in order to provide an unambiguous assessment of its appropriateness for use in ovarian surgical management. Methods We assessed the effects of HA-CMC barrier on the in vitro proliferation of human ovarian tumor cell lines (OVCAR-3, IGROV-1 and SKOV-3). We next evaluated, in vivo in nude mice, the capacity of this biomaterial to regulate the tumor progression of subcutaneous and intraperitoneal models of ovarian tumor xenografts. Results We showed that HA-CMC barrier does not increase in vitro proliferation of ovarian cancer cell lines compared to control. In vivo, HA-CMC barrier presence with subcutaneous xenografts induced neither an increase in tumor volume nor cell proliferation (Ki67 and mitotic index). With the exception of an increased murine carcinosis score in peritoneum, the presence of HA-CMC barrier with intraperitoneal xenografts modified neither macro nor microscopic tumor growth. Finally, protein analysis of survival (Akt), proliferation (ERK) and adhesion (FAK) pathways highlighted no activation on the xenografts imputable to HA-CMC barrier. Conclusions For the most part, our results support the lack of tumor progression activation due to HA-CMC barrier. We conclude that the benefits gained from using HA-CMC barrier membrane during ovarian cancer surgeries seem to outweigh the potential oncological risks. PMID:24739440

Mechanism of H adatoms improving the O2 reduction reaction on the Zn-modified anatase TiO2 (101) surface studied by first principles calculation.

PubMed

Liu, Liangliang; Li, Chongyang; Jiang, Man; Li, Xiaodong; Huang, Xiaowei; Wang, Zhu; Jia, Yu

2018-06-05

First principles calculations were performed to cast insight into the mechanism of the improvement of O2 reduction reaction (ORR) activity by Zn and H interstitials on the anatase TiO2 (101) surface. For the Zn-modified anatase TiO2 (101) surface, both surface and subsurface Zn interstitials could contribute to O2 adsorption and dissociation, but the dissociation barriers of O2 molecules are still too high, which limits the ORR activity. After a H adatom is introduced onto the Zn-modified anatase TiO2 (101) surface, the highest energy barriers are greatly reduced compared with those of the Zn-modified surface. Meanwhile, it is observed that the dissociation barriers decrease almost linearly with the increase of the charge difference of adsorption O2 between initial and transition state configurations. Specifically, subsurface Zn and surface H interstitials facilitate O2 dissociation and subsequent oxidation reactions, and further frequency analysis shows that these dissociation processes are frequent even at the room temperature of 300 K. In a word, this work provides a theoretical support to design a high ORR activity catalyst of the TiO2 nanocrystal comparable to precious Pt catalysts.

Efficacy of IPL device combined with intralesional corticosteroid injection for the treatment of keloids and hypertrophic scars with regards to the recovery of skin barrier function: A pilot study.

PubMed

Kim, Dong Young; Park, Hyun Sun; Yoon, Hyun-Sun; Cho, Soyun

2015-10-01

Keloids and hypertrophic scars are prevalent and psychologically distressful dermatologic conditions. Various treatment modalities have been tried but without complete success by any one method. We evaluated the efficacy of a combination of intense pulsed light (IPL) device and intralesional corticosteroid injection for the treatment of keloids and hypertrophic scars with respect to the recovery of skin barrier function. Totally 52 Korean patients were treated by the combined treatment at 4-8-week intervals. Using digital photographs, changes in scar appearance were assessed with modified Vancouver Scar Scale (MVSS), physicians' global assessment (PGA) and patient's satisfaction score. In 12 patients, the stratum corneum (SC) barrier function was assessed by measuring transepidermal water loss (TEWL) and SC capacitance. Most scars demonstrated significant clinical improvement in MVSS, PGA and patient's satisfaction score after the combined therapy. A significant decrease of TEWL and elevation of SC capacitance were also documented after the treatment. The combination therapy (IPL + corticosteroid injection) not only improves the appearance of keloids and hypertrophic scars but also increases the recovery level of skin hydration status in terms of the skin barrier function.

Nationally Certified School Psychologists' use and reported barriers to using evidence-based interventions in schools: the influence of graduate program training and education.

PubMed

Hicks, Taylor B; Shahidullah, Jeffrey D; Carlson, John S; Palejwala, Mohammed H

2014-12-01

The purpose of this study was to empirically investigate Nationally Certified School Psychologists' (NCSP) training in and use of evidence-based interventions (EBIs) for child behavior concerns as well as their reported implementation barriers. A modified Tailored Design Method (TDM; Dillman, Smyth, & Christian, 2009) using up to four mail-based participant contacts was used to obtain survey data (72% usable response rate; n = 392) from a randomly selected national sample of 548 currently practicing NCSPs. Lack of time was rated as the most serious barrier to behavioral EBI implementation, followed by a lack of necessary resources, and financial constraints. Nearly three-quarters (71%) of respondents reported a perceived inadequacy of graduate program training in behavioral EBIs, with a statistically significant difference found between respondents who attended American Psychological Association (APA)-accredited/National Association of School Psychologists (NASP)-approved programs and those who did not. These findings highlight the significant barriers school psychologists encounter when attempting to implement behavioral EBIs within applied practice, as well as the importance of graduate program training in implementation science. Implications for training, practice, and research are discussed. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Quasicontinuum analysis of dislocation-coherent twin boundary interaction to provide local rules to discrete dislocation dynamics

NASA Astrophysics Data System (ADS)

Tran, H.-S.; Tummala, H.; Duchene, L.; Pardoen, T.; Fivel, M.; Habraken, A. M.

2017-10-01

The interaction of a pure screw dislocation with a Coherent Twin Boundary Σ3 in copper was studied using the Quasicontinuum method. Coherent Twin Boundary behaves as a strong barrier to dislocation glide and prohibits slip transmission across the boundary. Dislocation pileup modifies the stress field at its intersection with the Grain Boundary (GB). A methodology to estimate the strength of the barrier for a dislocation to slip across CTB is proposed. A screw dislocation approaching the boundary from one side either propagates into the adjacent twin grain by cutting through the twin boundary or is stopped and increases the dislocation pileup amplitude at the GB. Quantitative estimation of the critical stress for transmission was performed using the virial stress computed by Quasicontinuum method. The transmission mechanism and critical stress are in line with the literature. Such information can be used as input for dislocation dynamic simulations for a better modeling of grain boundaries.

Neighborhood walking among overweight and obese adults: age variations in barriers and motivators.

PubMed

Lee, Chanam; Ory, Marcia G; Yoon, Jeongjae; Forjuoh, Samuel N

2013-02-01

Walking is a popular form of physical activity that can bring many public health benefits. It can be even more beneficial to those who are currently obese or overweight. However, many barriers discourage people from walking, ranging from lack of motivation to unsafe neighborhood environments, and such barriers vary with age. This study addresses barriers and motivators to walking among overweight and obese adults, and examines their age variations. Particular emphasis was given to modifiable environmental factors as the priority intervention targets. A survey of 161 overweight and obese adults recruited from a large integrated healthcare system in central Texas provided data on walking, demographics, motivators and barriers. Descriptive statistics and correlation analysis were conducted. The respondents had a mean age of 48.4 (20-86), and were predominantly female (80.8%), non-Hispanic White (86.0%), and obese (mean BMI = 32.5). Popular environmental barriers to walking were: bad weather, inadequate lighting, no shade, unattended dogs, disconnected sidewalks, poor walking surfaces, no interesting places to walk nearby, and no benches (74.5-38.5%). Even and smooth walking surfaces and benches were more frequently reported by older adults as motivators. Proximity to recreational facilities was a stronger motivator for younger adults. Two safety related barriers, fear of injury (older adults) and traffic safety concerns (younger adults), also showed significant age differences. Overweight and obese adults experience substantial environmental barriers to walking, but many of them are modifiable. Observed age variations suggest that future interventions may be more effective if tailored to address age-specific barriers.

Measuring the barriers against seeking consultation for urinary incontinence among Middle Eastern women

PubMed Central

2010-01-01

Background Existing questionnaires to assess barriers against consultation for urinary incontinence (UI) are not appropriate for use in the Middle East culture. The aim of this study was to explore barriers against seeking help for UI and introducing a questionnaire that assess these barriers among those women. This is important before proceeding to any educational programs or having interval clinical audits to help incontinent women. Methods 1- Screening for UI. Women - aged 20 years and older, attending the outpatient Urology and Gynaecology clinics were invited to participate and interviewed by a research nurse. The UDI-6 was administered to assess the presence and type of UI. Women with UI as their chief complaint were excluded. 2- Interviewing study subjects for possible barriers. Subjects who had UI - as determined by the UDI-6-were first asked an open question "what prevented you from seeking medical consultation for urine leakage?"." They were then asked the proposed questions to assess possible barriers. We developed a preliminary questionnaire based on a review of reasons for not seeking incontinence care from the literature and the response of UI sufferers to the open question in this study. The questionnaire was modified many times to reach this final form. 3- Pilot Study to assess characteristics of the questionnaire. Validity and reliability of the final version of the questionnaire were assessed in a small pilot study including 36 women who completed questionnaire at initial visit and again after 2 weeks. Results Of the 1231 subjects who agreed to participate in the study, 348 reported having UI. About 80% of incontinent women have never sought medical advice. Factors significantly associated with seeking help were husband encouragement, prayer affection and having severe UI. Common barriers were embarrassment and assuming UI as a normal part of aging. A pilot study included 36 women to assess the psychometric properties of the questionnaire after modifying it. The number of missing or not interpretable responses per item ranged from 2.2% to 8.7%. Internal consistency of the items was good. The test-retest reliability of individual items of the questionnaire was variable, with weighted kappa statistics ranging from 0.32 to 0.94 (median, 0.76, p 0.000). Conclusions Preliminary data on our proposed questionnaire show that it is an easy to administer, stable and suits the Middle Eastern culture. PMID:20105307

Analysis of the barriers and enablers to implementing lifestyle management practices for women with PCOS in Singapore.

PubMed

Ko, Henry; Teede, Helena; Moran, Lisa

2016-06-16

Polycystic ovary syndrome (PCOS) is a condition that affects women of reproductive age and manifests with adverse reproductive, metabolic and psychological consequences. Evidence-based PCOS guidelines recommend lifestyle management first line for infertility. In Singapore women with PCOS can attend the PCOS Clinic at the Kandang Kerbau Women and Children's Hospital for infertility treatment. However lifestyle integration into infertility management is currently limited and barriers and enablers to progress remain unclear. All PCOS clinic staff undertook semi-structured interviews to investigate perceived barriers for staff and consumers for the integration of lifestyle into infertility management. This study utilised various tools including an 8P Ishikawa diagram model to identify and categorise barriers. A modified Hanlon method was then used to prioritise barriers within the Singaporean context considering organisational, cultural and financial constraints. Propriety, economics, acceptability, resources and legality (PEARL) criteria were also incorporated into this decision-making tool. In the 8P model, there were five factors contributing to the 'procedure (consultations and referral processes)' barrier, one 'policy (government and hospitals)' factor, five 'place' factors, two 'product (lifestyle management programme)' barriers, two 'people (programme capacity)' factors, four 'process (integration)' factors, three 'promotion' barriers and three 'price' factors. Of the prioritised barriers, two were identified across each of 'procedures', 'place', 'product' and 'people' and four related to 'processes'. There were no barriers identified that for 'policies', 'promotion' and 'price' that can be addressed. There is a clear need to integrate lifestyle into infertility management in PCOS, in line with current national and international evidence-based guidelines. The highest priority identified improvement opportunity was to develop a collaborative lifestyle management programme across hospital services. Reductions in variation of delivery and strengthening support within the lifestyle programme are other identified priorities. The strength of this study is that this is the first study to utilise a pragmatic quality improvement method for barriers identification and prioritisation in the area of lifestyle management for women with PCOS. This project identified factors that may provide easy improvements, but also identified some local factors that may be very difficult to change. The major limitation of this study is that it is only looking at the Singapore setting, so may have limited applicability to other countries. However, results from quality improvement projects are meant to be context specific.

Barriers to patient involvement in health service planning and evaluation: an exploratory study.

PubMed

Gagliardi, Anna R; Lemieux-Charles, Louise; Brown, Adalsteinn D; Sullivan, Terrence; Goel, Vivek

2008-02-01

Patient involvement in health service planning and evaluation is considered important yet not widely practiced. This study explored stakeholder beliefs about patient participation in performance indicator selection to better understand hypothesized barriers. Interviews with 30 cancer patients and health professionals from two teaching hospitals were analyzed qualitatively. All groups believed patients, not members of the public, should be involved in the selection of indicators. Ongoing, interactive methods such as committee involvement, rather than single, passive efforts such as surveys were preferred. Health professionals recommended patients assume a consultative, rather than decision-making role. Older patients agreed with this. Variable patient interest, health professional attitudes, and a lack of insight on appropriate methods may be limiting patient involvement in this, and other service planning and evaluation activities. More research is required to validate expressed views among the populations these stakeholders represent, and to establish effective methods for engaging patients. Efforts to encourage a change in health professional attitude may be required, along with dedicated organizational resources, coordinators and training. Methods to engage patients should involve deliberation, which can be achieved through modified Delphi panel or participatory research approaches.

Fish passage in a western Iowa stream modified by grade control structures

USGS Publications Warehouse

Litvan, M.E.; Pierce, C.L.; Stewart, T.W.; Larson, C.J.

2008-01-01

Grade control structures (GCSs) are commonly used in streams of western Iowa to control bank erosion and channel headcutting but may be barriers to fish passage. From May 2002 to May 2006, we used mark-recapture methods to evaluate fish passage over a total of five GCSs, ranging in slope (run : rise) from 13:1 to 18:1 in Turkey Creek, Cass County, Iowa. Three structures, over which limited fish movement was documented from 2002 to 2004, were modified in the winter of 2004-2005 to facilitate fish passage. Before modification, the majority of recaptured fish were recaptured at the station where they were originally marked; only 1% displayed movement between sites and either upstream or downstream over a GCS. After modification fish passage improved, 14% of recaptured fish displayed movement either upstream or downstream over a GCS. Individuals of four target species - channel catfish Ictalurus punctatus, yellow bullhead Ameiurus natalis, black bullhead A. melas, and creek chub Semotilus atromaculatus - passed over at least one modified structure. The majority of documented movements over GCSs were in the upstream direction and occurred in late spring and early summer, when streamflow was relatively high. Although we documented low numbers of fish passing both upstream and downstream over GCSs, these structures are probably barriers to fish movement during periods of low flow and when there is a structural failure, such as in-channel movement of riprap. Grade control structures are pervasive in western Iowa streams; nearly every low-order stream contains at least one instream structure. To sustain fish populations, management efforts should focus on constructing or modifying GCSs to allow fish passage. ?? Copyright by the American Fisheries Society 2008.

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

Cheng, Liwen, E-mail: lwcheng@yzu.edu.cn; Wu, Shudong; Xia, Changquan

In this work, graded barrier InGaN light-emitting diodes with increasing indium composition barriers are proposed and investigated numerically. When the conventional GaN barriers are replaced by this unique graded InGaN barrier design, the forward voltage at 100 mA is reduced from 3.32 V to 3.27 V, and the efficiency droop is improved from 46.6% to 7.5%. The simulation results observed in this work indicate that these improvements can be attributed to increased electron confinement and enhanced hole injection efficiency caused by the modified energy band diagram.

[Mental health care for migrants].

PubMed

Lindert, Jutta; Priebe, Stefan; Penka, Simone; Napo, Fatima; Schouler-Ocak, Meryam; Heinz, Andreas

2008-01-01

Global migration and the increasing number of migrants to Europe and Germany diversify the needs in the psychosocial and health care system. Migrants are a heterogeneous group as regards their country of emigration, reasons for migration and legal status. We aim to give an overview on 1) mental health of migrants in Germany, 2) cultural associated explanatory of addictive behaviour, 3) utilisation and help-seeking behaviour migrants with particular regard to addicted migrants, and on 4) barriers within the psychosocial care system. Studies on migration, mental health and utilisation of psychosocial institutions especially of institutions for addicted persons show inconsistent results. The results may be conflicting because of the methods used (e. g. small sample size, variety of methods, studies on clinical populations, studies without control-groups, mono-ethnic studies) or because of differences between populations. Therefore, the comparability of results is limited. Migrants use health and psychosocial care institutions differently from non-migrants. Barriers within the psychosocial care system may be caused by uncertainty of learned behaviour of members of staff how to treat migrants or by institutional barriers. Our findings show that empirical studies on mental health of migrants are still rare. Further specific investigations are needed to get an in-depth understanding of migrants' mental health and their pattern of psychosocial and health care utilisation to modify responsiveness of services.

Robust Superhydrophobic Graphene-Based Composite Coatings with Self-Cleaning and Corrosion Barrier Properties.

PubMed

Nine, Md J; Cole, Martin A; Johnson, Lucas; Tran, Diana N H; Losic, Dusan

2015-12-30

Superhydrophobic surfaces for self-cleaning applications often suffer from mechanical instability and do not function well after abrasion/scratching. To address this problem, we present a method to prepare graphene-based superhydrophobic composite coatings with robust mechanical strength, self-cleaning, and barrier properties. A suspension has been formulated that contains a mixture of reduced graphene oxide (rGO) and diatomaceous earth (DE) modified with polydimethylsiloxane (PDMS) that can be applied on any surface using common coating methods such as spraying, brush painting, and dip coating. Inclusion of TiO2 nanoparticles to the formulation shows further increase in water contact angle (WCA) from 159 ± 2° to 170 ± 2° due to the structural improvement with hierarchical surface roughness. Mechanical stability and durability of the coatings has been achieved by using a commercial adhesive to bond the superhydrophobic "paint" to various substrates. Excellent retention of superhydrophobicity was observed even after sandpaper abrasion and crosscut scratching. A potentiodynamic polarization study revealed excellent corrosion resistance (96.78%) properties, and an acid was used to provide further insight into coating barrier properties. The ease of application and remarkable properties of this graphene-based composite coating show considerable potential for broad application as a self-cleaning and protective layer.

How Landscape Plants Modify the Environment.

ERIC Educational Resources Information Center

Blankenship, Sylvia; Wise, Kevin

1993-01-01

Presents three experiments that provide examples of how plants modify their surroundings and create microenvironments. Examples demonstrate (1) how types of ground cover influence water quality; (2) how plants can create a thermal microenvironment; and (3) how plants can serve as barriers to wind. (MDH)

Nanoparticles of alkylglyceryl-dextran-graft-poly(lactic acid) for drug delivery to the brain: Preparation and in vitro investigation.

PubMed

Toman, Petr; Lien, Chun-Fu; Ahmad, Zeeshan; Dietrich, Susanne; Smith, James R; An, Qian; Molnár, Éva; Pilkington, Geoffrey J; Górecki, Darek C; Tsibouklis, John; Barbu, Eugen

2015-09-01

Poly(lactic acid), which has an inherent tendency to form colloidal systems of low polydispersity, and alkylglyceryl-modified dextran - a material designed to combine the non-immunogenic and stabilising properties of dextran with the demonstrated permeation enhancing ability of alkylglycerols - have been combined for the development of nanoparticulate, blood-brain barrier-permeating, non-viral vectors. To this end, dextran, that had been functionalised via treatment with epoxide precursors of alkylglycerol, was covalently linked to poly(lactic acid) using a carbodiimide cross-linker to form alkylglyceryl-modified dextran-graft-poly(lactic acid). Solvent displacement and electrospray methods allowed the formulation of these materials into nanoparticles having a unimodal size distribution profile of about 100-200nm and good stability at physiologically relevant pH (7.4). The nanoparticles were characterised in terms of hydrodynamic size (by Dynamic Light Scattering and Nanoparticle Tracking Analysis), morphology (by Scanning Electron Microscopy and Atomic Force Microscopy) and zeta potential, and their toxicity was evaluated using MTT and PrestoBlue assays. Cellular uptake was evidenced by confocal microscopy employing nanoparticles that had been loaded with the easy-to-detect Rhodamine B fluorescent marker. Transwell-model experiments employing mouse (bEnd3) and human (hCMEC/D3) brain endothelial cells revealed enhanced permeation (statistically significant for hCMEC/D3) of the fluorescent markers in the presence of the nanoparticles. Results of studies using Electric Cell Substrate Impedance Sensing suggested a transient decrease of the barrier function in an in vitro blood-brain barrier model following incubation with these nanoformulations. An in ovo study using 3-day chicken embryos indicated the absence of whole-organism acute toxicity effects. The collective in vitro data suggest that these alkylglyceryl-modified dextran-graft-poly(lactic acid) nanoparticles are promising candidates for in vivo evaluations that would test their capability to transport therapeutic actives to the brain. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Experimental analysis of the Schottky barrier height of metal contacts in black phosphorus field-effect transistors

NASA Astrophysics Data System (ADS)

Chang, Hsun-Ming; Fan, Kai-Lin; Charnas, Adam; Ye, Peide D.; Lin, Yu-Ming; Wu, Chih-I.; Wu, Chao-Hsin

2018-04-01

Compared to graphene and MoS2, studies on metal contacts to black phosphorus (BP) transistors are still immature. In this work, we present the experimental analysis of titanium contacts on BP based upon the theory of thermionic emssion. The Schottky barrier height (SBH) is extracted by thermionic emission methods to analyze the properties of Ti-BP contact. To examine the results, the band gap of BP is extracted followed by theoretical band alignment by Schottky-Mott rule. However, an underestimated SBH is found due to the hysteresis in electrical results. Hence, a modified SBH extraction for contact resistance that avoids the effects of hysteresis is proposed and demonstrated, showing a more accurate SBH that agrees well with theoretical value and results of transmission electron microscopy and energy-dispersive x-ray spectroscopy.

Improving safety culture in hospitals: Facilitators and barriers to implementation of Systemic Falls Investigative Method (SFIM).

PubMed

Zecevic, Aleksandra A; Li, Alvin Ho-Ting; Ngo, Charity; Halligan, Michelle; Kothari, Anita

2017-06-01

The purpose of this study was to assess the facilitators and barriers to implementation of the Systemic Falls Investigative Method (SFIM) on selected hospital units. A cross-sectional explanatory mixed methods design was used to converge results from a standardized safety culture survey with themes that emerged from interviews and focus groups. Findings were organized by six elements of the Ottawa Model of Research Use framework. A geriatric rehabilitation unit of an acute care hospital and a neurological unit of a rehabilitation hospital were selected purposefully due to the high frequency of falls. Hospital staff who took part in: surveys (n = 39), interviews (n = 10) and focus groups (n = 12), and 38 people who were interviewed during falls investigations: fallers, family, unit staff and hospital management. Implementation of the SFIM to investigate fall occurrences. Percent of positive responses on the Modified Stanford Patient Safety Culture Survey Instrument converged with qualitative themes on facilitators and barriers for intervention implementation. Both hospital units had an overall poor safety culture which hindered intervention implementation. Facilitators were hospital accreditation, strong emphasis on patient safety, infrastructure and dedicated champions. Barriers included heavy workloads, lack of time, lack of resources and poor communication. Successful implementation of SFIM requires regulatory and organizational support, committed frontline staff and allocation of resources to identify active causes and latent contributing factors to falls. System-wide adjustments show promise for promotion of safety culture in hospitals where falls happen regularly. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Surface modification of polyvinyl alcohol/malonic acid nanofibers by gaseous dielectric barrier discharge plasma for glucose oxidase immobilization

NASA Astrophysics Data System (ADS)

Afshari, Esmail; Mazinani, Saeedeh; Ranaei-Siadat, Seyed-Omid; Ghomi, Hamid

2016-11-01

Polymeric nanofiber prepares a suitable situation for enzyme immobilization for variety of applications. In this research, we have fabricated polyvinyl alcohol (PVA)/malonic acid nanofibers using electrospinning. After fabrication of nanofibers, the effect of air, nitrogen, CO2, and argon DBD (dielectric barrier discharge) plasmas on PVA/malonic acid nanofibers were analysed. Among them, air plasma had the most significant effect on glucose oxidase (GOx) immobilization. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrum analysis and X-ray photoelectron spectroscopy (XPS) results revealed that in case of air plasma modified nanofibers, the carboxyl groups on the surface are increased. The scanning electron microscopy (SEM) images showed that, after GOx immobilization, the modified nanofibers with plasma has retained its nanofiber structure. Finally, we analysed reusability and storage stability of GOx immobilized on plasma modified and unmodified nanofibers. The results were more satisfactory for modified nanofibers with respect to unmodified ones.

What is killing? People's knowledge about coronary heart disease, attitude towards prevention and main risk reduction barriers in Ismailia, Egypt (descriptive cross-sectional study).

PubMed

Seef, Sameh; Jeppsson, Anders; Stafström, Martin

2013-01-01

Cardiovascular diseases are a public health concern everywhere, especially ischemic or coronary heart diseases (CHD) which are on top of causes list of mortality and morbidity in both genders globally. From which nearly 80% can be because of modifiable risks. In Egypt, there is a lack of studies on the knowledge of people about coronary heart diseases and its modifiable risks. So, this research reported here we designed to measure the dimensions of peoples knowledge about CHD and their attitude towards prevention, and to identify the main risk reduction barriers. By using comprehensive cross-sectional, descriptive research design, all adult individuals attending the family health clinic at Suez Canal University Hospital were eligible for inclusion with total number 125 participants. An interview questionnaire designed and used to collect data. The study revealed that (10.4%) of participants had a history of CHD, and (7.2%) had a family history of CHD. 79.2% Had a satisfactory total knowledge about CHD, and (94.4%) had a positive total attitude towards prevention. Risk reduction barriers as a medical setting barriers were (24%), patient related barriers were (22.4%). Community-societal barriers were almost the same as knowledge barriers which were around (16%). At last the systemic-organizational barriers were (9.6%). The findings settled that, total knowledge about CHD was satisfactory but lower than the level total of attitude. More effort the health system needs to improve the settings and engage patients in their plans and breaking related barriers, with development of health education programs based on needs assessment. Further studies we recommend to explore the reasons and follow up the changes.

Latina and Non-Latina Mothers' Perceived Health Barriers and Benefits and Their Relationship to Children's Health Behaviors.

PubMed

Highland, Krista B; Lundahl, Alyssa; Kidwell, Katherine M; Hankey, Maren; Caballos, Miguel; McChargue, Dennis

2016-06-01

Objectives Disparities exist in rates of overweight/obesity between Latino and non-Latino populations. Attention should be given to risk factors that may be modifiable through interventions involving both the parent and child. The current study sought to identify ethnic differences in parental health beliefs and their relation to children's health behaviors. Methods Latina and non-Latina mothers (N = 203) at rural and urban clinics and health departments completed self-report questionnaires. Key information included beliefs about barriers and benefits to health practices and children's health behaviors. Results Children of Latina mothers consumed significantly more soda and fried foods and exercised less than children of non-Latina mothers. Latina mothers were significantly more likely to perceive barriers to healthy eating and significantly less likely to perceive benefits to healthy eating and physical activity than non-Latina mothers. Ethnicity mediated the relationship between maternal views of health benefits and soda consumption. Conclusions Policy changes are needed to promote health education and increase the accessibility of healthy foods and safe places to exercise for Latino families.

Surface Modified Pinecone Shaped Hierarchical Structure Fluorinated Mesocarbon Microbeads for Ultrafast Discharge and Improved Electrochemical Performances

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

Dai, Yang; Fang, Yuan; Cai, Sendan

2016-12-01

Among all primary lithium batteries, Li/CF x primary battery possesses the highest energy density of 2180 Wh kg -1. However, a key limitation is its poor rate capability because the cathode material CF x is intrinsically a poor electronic conductor. Here, we developed a so-called “doing subtraction” method to modify the pinecone shaped fluorinated mesocarbon microbead (F-MCMB). The modified fluorinated mesocarbon microbead (MF-MCMB), manifests the advantage of open-framed structure, possesses good electronic conductivity and removes transport barrier for lithium ions. Thus, high capacity performance and excellent rate capability without compromising capacity can be obtained. A capacity of 343 mAhg -1more » and a maximum power density of 54600 W kg -1 are realized at an ultrafast rate of 40 C (28A g -1). Additionally, the MF-MCMB cathode does not show any voltage delay even at 5C during the discharge, which is a remarkable improvement over the state-of-the-art CF xmaterials.« less

Dielectric barrier discharge atmospheric cold plasma inhibits Escherichia coli 0157:H7, Salmonella, Listeria monocytogenes, and Tulane virus in Romaine lettuce

USDA-ARS?s Scientific Manuscript database

The present study investigated the effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus (TV) on Romaine lettuce, assessing the influences of moisture vaporization, modifi...

Improvement of interfacial interactions using natural polyphenol-inspired tannic acid-coated nanoclay enhancement of soy protein isolate biofilms

NASA Astrophysics Data System (ADS)

Wang, Zhong; Kang, Haijiao; Zhang, Wei; Zhang, Shifeng; Li, Jianzhang

2017-04-01

In this study, a novel and economic surface modification technique for montmorillonite (MMT) nanosheets, a biocompatible coupling cross-linking agent, was developed on an attempt at improving the interfacial adhesion with soy protein isolate (SPI) matrix. Inspired by natural polyphenol, the "green dip-coating" method using tannic acid (TA) to surface-modify MMT (TA@MMT). SPI nanocomposite films modified with MMT or TA@MMT, as well as the control ones, were prepared via the casting method. The TA layer was successfully coated on the MMT surface through the (FeIII) ions coordination chemistry and the synthetic samples were characterized by the Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The compatibility and interfacial interactions between modified MMT and SPI matrix were greatly enhanced by the TA-FeIII coating on the MMT surface. The mechanical properties, water resistance, and thermal stability of the resultant biofilm were increased accordingly. Compared with that of the unmodified SPI film, the tensile strength of the nanocomposite films modified by the green dip-coating was increased by 113.3%. These SPI-based nanocomposite films showed the favorable potential in terms of food packing applications due to their efficient barriers to water vapor and UV and/or visible light.

Exponential blocking-temperature distribution in ferritin extracted from magnetization measurements

NASA Astrophysics Data System (ADS)

Lee, T. H.; Choi, K.-Y.; Kim, G.-H.; Suh, B. J.; Jang, Z. H.

2014-11-01

We developed a direct method to extract the zero-field zero-temperature anisotropy energy barrier distribution of magnetic particles in the form of a blocking-temperature distribution. The key idea is to modify measurement procedures slightly to make nonequilibrium magnetization calculations (including the time evolution of magnetization) easier. We applied this method to the biomagnetic molecule ferritin and successfully reproduced field-cool magnetization by using the extracted distribution. We find that the resulting distribution is more like an exponential type and that the distribution cannot be correlated simply to the widely known log-normal particle-size distribution. The method also allows us to determine the values of the zero-temperature coercivity and Bloch coefficient, which are in good agreement with those determined from other techniques.

A systematic approach for the accurate and rapid measurement of water vapor transmission through ultra-high barrier films

NASA Astrophysics Data System (ADS)

Kiese, Sandra; Kücükpinar, Esra; Reinelt, Matthias; Miesbauer, Oliver; Ewender, Johann; Langowski, Horst-Christian

2017-02-01

Flexible organic electronic devices are often protected from degradation by encapsulation in multilayered films with very high barrier properties against moisture and oxygen. However, metrology must be improved to detect such low quantities of permeants. We therefore developed a modified ultra-low permeation measurement device based on a constant-flow carrier-gas system to measure both the transient and stationary water vapor permeation through high-performance barrier films. The accumulation of permeated water vapor before its transport to the detector allows the measurement of very low water vapor transmission rates (WVTRs) down to 2 × 10-5 g m-2 d-1. The measurement cells are stored in a temperature-controlled chamber, allowing WVTR measurements within the temperature range 23-80 °C. Differences in relative humidity can be controlled within the range 15%-90%. The WVTR values determined using the novel measurement device agree with those measured using a commercially available carrier-gas device from MOCON®. Depending on the structure and quality of the barrier film, it may take a long time for the WVTR to reach a steady-state value. However, by using a combination of the time-dependent measurement and the finite element method, we were able to estimate the steady-state WVTR accurately with significantly shorter measurement times.

Evaluation of smallpox vaccines using variola neutralization.

PubMed

Damon, Inger K; Davidson, Whitni B; Hughes, Christine M; Olson, Victoria A; Smith, Scott K; Holman, Robert C; Frey, Sharon E; Newman, Frances; Belshe, Robert B; Yan, Lihan; Karem, Kevin

2009-08-01

The search for a 'third'-generation smallpox vaccine has resulted in the development and characterization of several vaccine candidates. A significant barrier to acceptance is the absence of challenge models showing induction of correlates of protective immunity against variola virus. In this light, virus neutralization provides one of few experimental methods to show specific 'in vitro' activity of vaccines against variola virus. Here, we provide characterization of the ability of a modified vaccinia virus Ankara vaccine to induce variola virus-neutralizing antibodies, and we provide comparison with the neutralization elicited by standard Dryvax vaccination.

Modified Pressure Imaging for Egg Crack Detection and Resulting Egg Quality

USDA-ARS?s Scientific Manuscript database

Cracks in the shell surface impair the primary barrier for external microbial contamination of the egg. Microcracks are very small cracks in the shell surface which are difficult to detect by human graders. New technology has been developed which utilizes modified pressure and imaging to detect mi...

Perceptions of reporting practices and barriers to reporting incidents among registered nurses and physicians in accredited and nonaccredited Jordanian hospitals.

PubMed

AbuAlRub, Raeda F; Al-Akour, Nemeh A; Alatari, Nour H

2015-10-01

To explore the awareness of the incident reporting system, incident reporting practices and barriers to reporting incidents among Jordanian staff nurses and physicians in accredited and nonaccredited hospitals. Reporting medical incidents is an important element of patient safety enhancement and quality of care improvement and it should be an integral part of the organisational culture. A descriptive exploratory survey was used for the present study. A modified version of the Incident Reporting Questionnaire was used to collect data from 307 nurses and 144 physicians at seven hospitals (four accredited and three not accredited) in Jordan. The response rate was 28·8% for nurses and 58·8% for physicians. Nurses were more aware of the incident reporting system than physicians. Physicians were less likely to report any incident on 50% or more of occasions. The major three barriers to reporting incidents were believing that there was no point in reporting near misses, lack of feedback and fear of disciplinary actions. The study showed significant differences between nurses in accredited and nonaccredited hospitals regarding barriers to reporting incidents and reporting practices. Nurse administrators should modify existing systems for reporting incidents to overcome the barriers as shown in the present study. © 2015 John Wiley & Sons Ltd.

Testing an Adapted Modified Delphi Method: Synthesizing Multiple Stakeholder Ratings of Health Care Service Effectiveness.

PubMed

Escaron, Anne L; Chang Weir, Rosy; Stanton, Petra; Vangala, Sitaram; Grogan, Tristan R; Clarke, Robin M

2016-03-01

The Affordable Care Act incentivizes health systems for better meeting patient needs, but often guidance about patient preferences for particular health services is limited. All too often vulnerable patient populations are excluded from these decision-making settings. A community-based participatory approach harnesses the in-depth knowledge of those experiencing barriers to health care. We made three modifications to the RAND-UCLA appropriateness method, a modified Delphi approach, involving patients, adding an advisory council group to characterize existing knowledge in this little studied area, and using effectiveness rather than "appropriateness" as the basis for rating. As a proof of concept, we tested this method by examining the broadly delivered but understudied nonmedical services that community health centers provide. This method created discrete, new knowledge about these services by defining 6 categories and 112 unique services and by prioritizing among these services based on effectiveness using a 9-point scale. Consistent with the appropriateness method, we found statistical convergence of ratings among the panelists. Challenges include time commitment and adherence to a clear definition of effectiveness of services. This diverse stakeholder engagement method efficiently addresses gaps in knowledge about the effectiveness of health care services to inform population health management. © 2015 Society for Public Health Education.

Accelerating oxygen reduction on Pt monolayer via substrate compression

NASA Astrophysics Data System (ADS)

Zhang, Xilin; Chen, Yue; Yang, Zongxian; Lu, Zhansheng

2017-11-01

Many methods have been proposed to accelerate the oxygen reduction and save the dosage of Pt. Here, we report a promising way in fulfilling these purposes by applying substrate strain on the supported Pt monolayer. The compressive strain would modify the geometric and electronic structures of tungsten carbide (WC) substrate, changing the interaction nature between substrate and Pt monolayer and resulting in a downward shift of the d-band center of surface Pt atoms. The activity of Pt monolayer on the compressed WC is further evaluated from the kinetics of the dissociation and protonation of O2. The dissociation barrier of O2 is increased and the hydrogenation barrier of O atom is decreased, indicating that the recovery of the catalytically active sites is accelerated and the deactivation by oxygen poison is alleviated. The present study provides an effective way in tuning the activity of Pt-based catalysts by applying the substrate strain.

Validating the Modified Drug Adherence Work-Up (M-DRAW) Tool to Identify and Address Barriers to Medication Adherence.

PubMed

Lee, Sun; Bae, Yuna H; Worley, Marcia; Law, Anandi

2017-09-08

Barriers to medication adherence stem from multiple factors. An effective and convenient tool is needed to identify these barriers so that clinicians can provide a tailored, patient-centered consultation with patients. The Modified Drug Adherence Work-up Tool (M-DRAW) was developed as a 13-item checklist questionnaire to identify barriers to medication adherence. The response scale was a 4-point Likert scale of frequency of occurrence (1 = never to 4 = often). The checklist was accompanied by a GUIDE that provided corresponding motivational interview-based intervention strategies for each identified barrier. The current pilot study examined the psychometric properties of the M-DRAW checklist (reliability, responsiveness and discriminant validity) in patients taking one or more prescription medication(s) for chronic conditions. A cross-sectional sample of 26 patients was recruited between December 2015 and March 2016 at an academic medical center pharmacy in Southern California. A priming question that assessed self-reported adherence was used to separate participants into the control group of 17 "adherers" (65.4%), and into the intervention group of nine "unintentional and intentional non-adherers" (34.6%). Comparable baseline characteristics were observed between the two groups. The M-DRAW checklist showed acceptable reliability (13 item; alpha = 0.74) for identifying factors and barriers leading to medication non-adherence. Discriminant validity of the tool and the priming question was established by the four-fold number of barriers to adherence identified within the self-selected intervention group compared to the control group (4.4 versus 1.2 barriers, p < 0.05). The current study did not investigate construct validity due to small sample size and challenges on follow-up with patients. Future testing of the tool will include construct validation.

A photoemission moments model using density functional and transfer matrix methods applied to coating layers on surfaces: Theory

NASA Astrophysics Data System (ADS)

Jensen, Kevin L.; Finkenstadt, Daniel; Shabaev, Andrew; Lambrakos, Samuel G.; Moody, Nathan A.; Petillo, John J.; Yamaguchi, Hisato; Liu, Fangze

2018-01-01

Recent experimental measurements of a bulk material covered with a small number of graphene layers reported by Yamaguchi et al. [NPJ 2D Mater. Appl. 1, 12 (2017)] (on bialkali) and Liu et al. [Appl. Phys. Lett. 110, 041607 (2017)] (on copper) and the needs of emission models in beam optics codes have lead to substantial changes in a Moments model of photoemission. The changes account for (i) a barrier profile and density of states factor based on density functional theory (DFT) evaluations, (ii) a Drude-Lorentz model of the optical constants and laser penetration depth, and (iii) a transmission probability evaluated by an Airy Transfer Matrix Approach. Importantly, the DFT results lead to a surface barrier profile of a shape similar to both resonant barriers and reflectionless wells: the associated quantum mechanical transmission probabilities are shown to be comparable to those recently required to enable the Moments (and Three Step) model to match experimental data but for reasons very different than the assumption by conventional wisdom that a barrier is responsible. The substantial modifications of the Moments model components, motivated by computational materials methods, are developed. The results prepare the Moments model for use in treating heterostructures and discrete energy level systems (e.g., quantum dots) proposed for decoupling the opposing metrics of performance that undermine the performance of advanced light sources like the x-ray Free Electron Laser. The consequences of the modified components on quantum yield, emittance, and emission models needed by beam optics codes are discussed.

Environmental Determinants of Cardiovascular Diseases Risk Factors: A Qualitative Directed Content Analysis

PubMed Central

Sabzmakan, Leila; Mohammadi, Eesa; Morowatisharifabad, Mohammad Ali; Afaghi, Ahmad; Naseri, Mohammad Hassan; Mirzaei, Masoud

2014-01-01

Background: Cardiovascular diseases (CVDs) are the number one cause of death in the world. In most analyses of health problems, environment plays a significant and modifiable role in causing the problem either directly or indirectly through behavior. Objectives: This study aims to understand the patients and healthcare providers’ experiences about the environmental determinants of CVD risk factors based on the Precede Model. Patients and Methods: This qualitative study conducted over six months in 2012 at Diabetes Units of Health Centers associated with Alborz University of Medical Sciences and Health Services which is located in Karaj, Iran. The data were collected based on individual semi-structured interviews with 50 patients and 12 healthcare providers. Data analysis was performed simultaneous with data collection using the content analysis directed method. Results: Lack of behaviors like stress control, healthy eating and physical activity were the roots of the risk factors for CVD. The environmental factor is one of the barriers for conducting these behaviors. The environmental barriers included of structural environment including “availability and accessibility of health resources”, “new skills”, and “law and policies” which are located in enabling category and social environment including “social support”, “motivation to comply” and “consequences of behavior” which are located in reinforcing category. The most barriers to performing health behaviors were often structural. Conclusions: The environmental factors were barriers for doing healthy behaviors. These factors need to be considered to design health promotion interventions. Policymakers should not only focus on patients’ education but also should provide specific facilities to enhance economic, social and cultural status. PMID:25031848

Barriers to oral health across selected European countries and the USA.

PubMed

Manski, Richard; Moeller, John

2017-06-01

In this review we consider oral-health access among older adults within and between the USA and various European countries with regard to possible primary financial and modifiable secondary non-financial factors. For older adults, the likelihood of using dental services has been associated, in the health literature, with a multiplicity of factors. These factors are traditionally classified into predisposing, enabling and need categories, and can be further classified into modifiable and non-modifiable subcategories. This raises the question of which single factor or group of factors has the most influence in keeping older adults from seeking care, and how these influences might differ between the USA and various other (European) countries. As it turns out, there is variation in the magnitude of effects across certain measurable potential barriers, but generally it takes a combination of characteristics associated with non-use to have a substantial impact. © 2017 FDI World Dental Federation.

Barriers to Oral Health Across Selected European Countries and the United States

PubMed Central

Manski, Richard; Moeller, John

2016-01-01

In this review we consider oral health access among older adults within and between the United States and various European countries with regard to possible primary financial and modifiable secondary non-financial factors. For older adults, the likelihood of using dental services has been associated with a multiplicity of factors in the health literature. These factors are traditionally classified into predisposing, enabling, and need categories, and can be further classified into modifiable and non-modifiable sub-categories. This raises the question as to which single factor or group of factors has the most influence in keeping older adults from seeking care, and how might these influences differ between the USA and various other (European) countries. As it turns out, there is variation in the magnitude of effects across certain measurable potential barriers, but generally it takes a combination of characteristics associated with non-use to have a substantial impact. PMID:28083874

Midwest Guardrail System with round timber posts

Treesearch

Ronald K. Faller; John D. Reid; David E. Kretschmann; Jason A. Hascall; Dean L. Sicking

2009-01-01

A modified Midwest Guardrail System (MGS) was developed by using small-diameter round wood posts. The barrier system was configured with three timber species: Douglas fir (DF), ponderosa pine (PP), and southern yellow pine (SYP). Barrier VII computer simulation, combined with cantilever post testing in a rigid sleeve and soil, was used to determine the required post...

Underutilization of cervical cancer prevention services in low and middle income countries: a review of contributing factors

PubMed Central

Chidyaonga-Maseko, Fresier; Chirwa, Maureen Leah; Muula, Adamson Sinjani

2015-01-01

This review aims at identifying barriers to utilization of cervical cancer prevention services in low- and middle-income countries. An electronic search was conducted using the following key words, HPV vaccination, screening, barriers, utilization and low and middle income/developed countries. Using the Garrard (1999) Matrix method approach, a modified matrix was designed and used as a data collection tool and data related to each category listed on the tool were entered into a matrix containing columns reflecting the categories. Constant comparative analysis was used to identify thematic categories. 31 articles published between 2001 and 2014 were yielded from the search. Analysis of the contents of the articles showed that the underutilization of cervical cancer screening services in low and middle-income countries is the result of barriers in accessing and utilizing of the prevention services. Though not mutually exclusive, the barriers were categorized in three categories; individual, community and health system related. Individual barriers include lack of awareness and knowledge about risk factors and prevention of cervical cancer. Age, marital status, diffidence, social economic status, cultural and religious belief of the women also determine the women's' willingness to utilize the services. In some communities there is stigma attached to discussing reproductive health issues and this limits the young women's awareness of cervical cancer and its prevention. Understanding individual, community and health system barriers that hinder women's utilization of cervical cancer prevention services is very crucial in designing effective cervical cancer control programs in low- and middle-income countries. PMID:26523173

Hydrogen Abstraction by Chlorine Atom from Small Organic Molecules Containing Amino Acid Functionalities: An Assessment of Theoretical Procedures

NASA Astrophysics Data System (ADS)

Taylor, Mark S.; Ivanic, Sandra A.; Wood, Geoffrey P. F.; Easton, Christopher J.; Bacskay, George B.; Radom, Leo

2009-07-01

A high-level quantum chemistry investigation has been carried out for the abstraction by chlorine atom of hydrogen from methane and five monosubstituted methanes, chosen to reflect the chemical functionalities contained in amino acids and peptides. A modified W1' procedure is used to calculate benchmark barriers and reaction energies for the six reactions. The reactions demonstrate a broad range of barrier heights and reaction energies, which can be rationalized using curve-crossing and molecular orbital theory models. In addition, the performance of a range of computationally less demanding electronic structure methods is assessed for calculating the energy profiles for the six reactions. It is found that the G3X(MP2)-RAD procedure compares best with the W1' benchmark, demonstrating a mean absolute deviation (MAD) from W1' of 2.1 kJ mol-1. The more economical RMP2/G3XLarge and UB2-PLYP/G3XLarge methods are also shown to perform well, with MADs from W1' of 2.9 and 3.0 kJ mol-1, respectively.

Wetting transitions on patterned surfaces with diffuse interaction potentials embedded in a Young-Laplace formulation

NASA Astrophysics Data System (ADS)

Pashos, G.; Kokkoris, G.; Papathanasiou, A. G.; Boudouvis, A. G.

2016-01-01

The Minimum Energy Paths (MEPs) of wetting transitions on pillared surfaces are computed with the Young-Laplace equation, augmented with a pressure term that accounts for liquid-solid interactions. The interactions are smoothed over a short range from the solid phase, therefore facilitating the numerical solution of problems concerning wetting on complex surface patterns. The patterns may include abrupt geometric features, e.g., arrays of rectangular pillars, where the application of the unmodified Young-Laplace is not practical. The MEPs are obtained by coupling the augmented Young-Laplace with the modified string method from which the energy barriers of wetting transitions are eventually extracted. We demonstrate the method on a wetting transition that is associated with the breakdown of superhydrophobic behavior, i.e., the transition from the Cassie-Baxter state to the Wenzel state, taking place on a superhydrophobic pillared surface. The computed energy barriers quantify the resistance of the system to these transitions and therefore, they can be used to evaluate superhydrophobic performance or provide guidelines for optimal pattern design.

Effectiveness of antimicrobial food packaging materials.

PubMed

Cooksey, K

2005-10-01

Antimicrobial additives have been used successfully for many years as direct food additives. The literature provides evidence that some of these additives may be effective as indirect food additives incorporated into food packaging materials. Antimicrobial food packaging is directed toward the reduction of surface contamination of processed, prepared foods such as sliced meats and Frankfurter sausages (hot dogs). The use of such packaging materials is not meant to be a substitute for good sanitation practices, but it should enhance the safety of food as an additional hurdle for the growth of pathogenic and/or spoilage microorganisms. Studies have focused on establishing methods for coating low-density polyethylene film or barrier films with methyl cellulose as a carrier for nisin. These films have significantly reduced the presence of Listeria monocytogenes in solutions and in vacuum packaged hot dogs. Other research has focused on the use of chitosan to inhibit L. monocytogenes and chlorine dioxide sachets for the reduction of Salmonella on modified atmosphere-packaged fresh chicken breasts. Overall, antimicrobial packaging shows promise as an effective method for the inhibition of certain bacteria in foods, but barriers to their commercial implementation continue to exist.

An Evidential Reasoning-Based CREAM to Human Reliability Analysis in Maritime Accident Process.

PubMed

Wu, Bing; Yan, Xinping; Wang, Yang; Soares, C Guedes

2017-10-01

This article proposes a modified cognitive reliability and error analysis method (CREAM) for estimating the human error probability in the maritime accident process on the basis of an evidential reasoning approach. This modified CREAM is developed to precisely quantify the linguistic variables of the common performance conditions and to overcome the problem of ignoring the uncertainty caused by incomplete information in the existing CREAM models. Moreover, this article views maritime accident development from the sequential perspective, where a scenario- and barrier-based framework is proposed to describe the maritime accident process. This evidential reasoning-based CREAM approach together with the proposed accident development framework are applied to human reliability analysis of a ship capsizing accident. It will facilitate subjective human reliability analysis in different engineering systems where uncertainty exists in practice. © 2017 Society for Risk Analysis.

Methods for natural gas and heavy hydrocarbon co-conversion

DOEpatents

Kong, Peter C [Idaho Falls, ID; Nelson, Lee O [Idaho Falls, ID; Detering, Brent A [Idaho Falls, ID

2009-02-24

A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

Nonthermal plasma systems and methods for natural gas and heavy hydrocarbon co-conversion

DOEpatents

Kong, Peter C.; Nelson, Lee O.; Detering, Brent A.

2005-05-24

A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

Density function theory study of the adsorption and dissociation of carbon monoxide on tungsten nanoparticles.

PubMed

Weng, Meng-Hsiung; Ju, Shin-Pon; Chen, Hsin-Tsung; Chen, Hui-Lung; Lu, Jian-Ming; Lin, Ken-Huang; Lin, Jenn-Sen; Hsieh, Jin-Yuan; Yang, Hsi-Wen

2013-02-01

The adsorption and dissociation properties of carbon monoxide (CO) molecule on tungsten W(n) (n = 10-15) nanoparticles have been investigated by density-functional theory (DFT) calculations. The lowest-energy structures for W(n) (n = 10-15) nanoparticles are found by the basin-hopping method and big-bang method with the modified tight-binding many-body potential. We calculated the corresponding adsorption energies, C-O bond lengths and dissociation barriers for adsorption of CO on nanoparticles. The electronic properties of CO on nanoparticles are studied by the analysis of density of state and charge density. The characteristic of CO on W(n) nanoparticles are also compared with that of W bulk.

A pushing chronic care forward in Abu Dhabi by identifying priorities and addressing barriers: a modified Delphi technique

PubMed Central

Loney, Tom; Lapão, Luis V

2018-01-01

Objective This study aimed to elucidate the top five key priorities and barriers to chronic care in the health system of Abu Dhabi, United Arab Emirates (UAE). Design A modified Delphi study was performed to reach consensus on priority areas and barriers to the development of the Chronic Care Model in the health system of Abu Dhabi. Individual wireless audience response devices (keypads) linked to a computer were used to reduce 28 priorities and 20 barriers to the top five during three iterative rounds over three consecutive days. Setting Chronic care services for patients with diabetes, cardiovascular diseases and cancer, in both private and publicly funded healthcare services in the emirate of Abu Dhabi. Participants A purposive sample of 20 health systems’ experts were recruited. They were front-line healthcare workers from the public and private sector working in the delivery of care for patients with diabetes, cardiovascular diseases and cancer. Results The ‘overall organizational leadership in chronic illness care’ was ranked as the most important priority to address (26.3%) and ‘patient compliance’ was ranked as the most important barrier (36.8%) to the development of the Chronic Care Model. Conclusions This study has identified the current priorities and barriers to improving chronic care within Abu Dhabi’s healthcare system. Our paper addresses the UAE’s 2021 Agenda of achieving a world-class healthcare system, and findings may help inform strategic changes required to achieve this mission. PMID:29866724

Use of evidence-based interventions in state health departments: a qualitative assessment of barriers and solutions.

PubMed

Dodson, Elizabeth A; Baker, Elizabeth A; Brownson, Ross C

2010-01-01

Existing knowledge on chronic disease prevention is not systematically disseminated and applied. State-level public health practitioners are in positions to implement programs and services related to chronic disease control. To advance dissemination science, this study sought to evaluate how and why evidence-based decision making (EBDM) is occurring. Specifically, it identified barriers to using EBDM commonly faced by state-level chronic disease practitioners and solutions for increasing the use of EBDM. Descriptive research using online survey methods. State health departments. Members of the National Association of Chronic Disease Directors. Barriers to using EBDM and solutions to increase the use of EBDM. In total, 469 people completed the survey (64% response rate). More than 60% of respondents described their position as project managers or coordinators. Nearly 80% of respondents were women, and 39% reported at least a master's degree as their highest degree. The survey elicited responses from every US state and the District of Columbia. Commonly-cited barriers to using EBDM included lack of time, resources, funding, and data. Participants noted that promising solutions to increase the use of EBDM include improved leadership, training, and collaboration. These results identify several modifiable barriers to EBDM among state-level public health practitioners. This information may improve state health departments' abilities to facilitate and encourage EBDM. In turn, this may assist chronic disease practitioners in implementing chronic disease interventions that have been proven effective. The use of such interventions will improve public health through the prevention of chronic diseases.

Enablers and barriers to using two-way information technology in the management of adults with diabetes: A descriptive systematic review.

PubMed

Macdonald, Emma M; Perrin, Byron M; Kingsley, Michael Ic

2017-01-01

Background This systematic review aimed to explore the enablers and barriers faced by adults with diabetes using two-way information communication technologies to support diabetes self-management. Methods Relevant literature was obtained from five databases using search strategies combining four major constructs: adults with diabetes, biomedical technology, communication technology and patient utilisation. Results Of 8430 unique articles identified, 48 were included for review. Risk of bias was assessed using either the Newcastle-Ottowa or Cochrane risk of bias assessment tools. Seventy-one percent of studies were of cohort design with the majority of studies assessed at high or unclear risk of bias. Consistently identified barriers included poorly designed interfaces requiring manual data entry and systems that lacked functionalities valued by patients. Commonly cited enablers included access to reliable technology, highly automated data entry and transmission, graphical display of data with immediate feedback, and supportive health care professionals and family members. Conclusions People with diabetes face a number of potentially modifiable barriers in using technology to support their diabetes management. In order to address these barriers, end users should be consulted in the design process and consideration given to theories of technology adoption to inform design and implementation. Systems should be designed to solve clinical or behavioural problems that are identified by patients as priorities. Technology should be as automated, streamlined, mobile, low cost and integrated as possible in order to limit the burden of usage for the patient and maximise clinical usefulness.

Self-efficacy for physical activity and insight into its benefits are modifiable factors associated with physical activity in people with COPD: a mixed-methods study.

PubMed

Hartman, Jorine E; ten Hacken, Nick H T; Boezen, H Marike; de Greef, Mathieu H G

2013-06-01

What are the perceived reasons for people with chronic obstructive pulmonary disease (COPD) to be physically active or sedentary? Are those reasons related to the actual measured level of physical activity? A mixed-methods study combining qualitative and quantitative approaches. People with mild to very severe COPD. Participants underwent a semi-structured interview and physical activity was measured by a triaxial accelerometer worn for one week. Of 118 enrolled, 115 participants (68% male, mean age 65 years, mean FEV1 57% predicted, mean modified Medical Research Council dyspnoea score 1.4) completed the study. The most frequently reported reason to be physically active was health benefits, followed by enjoyment, continuation of an active lifestyle from the past, and functional reasons. The most frequently reported reason to be sedentary was the weather, followed by health problems, and lack of intrinsic motivation. Mean steps per day ranged between 236 and 18 433 steps. A high physical activity level was related to enjoyment and self-efficacy for physical activity. A low physical activity level was related to the weather influencing health, financial constraints, health and shame. We identified important facilitators to being physically active and barriers that could be amenable to change. Furthermore, we distinguished three important potential strategies for increasing physical activity in sedentary people with COPD, namely reducing barriers and increasing insight into health benefits, tailoring type of activity, and improvement of self-efficacy. Copyright © 2013 Australian Physiotherapy Association. Published by .. All rights reserved.

Simple Things Matter! How Reassurance and Pain Management Strategies Can Improve Outcomes in Physiotherapy: A Case Report

ERIC Educational Resources Information Center

Leonard, Guillaume; Tousignant-Laflamme, Yannick; Mercier, Catherine

2013-01-01

Psychological barriers to rehabilitation are generally viewed as pre-existing patient traits that clinicians are asked to evaluate and modify. In the present case report, we provide evidence that these barriers can also be involuntarily created or perpetuated by the clinician himself when too much attention is placed on physical abnormalities.…

Development of modified flyash as a permeable reactive barrier medium for a former manufactured gas plant site, Northern Ireland

NASA Astrophysics Data System (ADS)

Doherty, R.; Phillips, D. H.; McGeough, K. L.; Walsh, K. P.; Kalin, R. M.

2006-05-01

A sequential biological permeable reactive barrier (PRB) was determined to be the best option for remediating groundwater that has become contaminated with a wide range of organic contaminants (i.e., benzene, toluene, ethylbenzene, xylene and polyaromatic hydrocarbons), heavy metals (i.e., lead and arsenic), and cyanide at a former manufactured gas plant after 150 years of operation in Portadown, Northern Ireland. The objective of this study was to develop a modified flyash that could be used in the initial cell within a sequential biological PRB to filter complex contaminated groundwater containing ammonium. Flyash modified with lime (CaOH) and alum was subjected to a series of batch tests which investigated the modified cation exchange capacity (CEC) and rate of removal of anions and cations from the solution. These tests showed that a high flyash composition medium (80%) could remove 8.65 mol of ammonium contaminant for every kilogram of medium. The modified CEC procedure ruled out the possibility of cation exchange as the major removal mechanism. The medium could also adsorb anions as well as cations (i.e., Pb and Cr), but not with the same capacity. The initial mechanism for Pb and Cr removal is probably precipitation. This is followed by sorption, which is possibly the only mechanism for the removal of dichromate anions. Scanning electron microscopic analysis revealed very small (<1 μm) cubic highly crystalline precipitates on the flyash, although this new crystalline zeolite growth did not occur rapidly enough to enable productive zeolite formation. Surface area measurements showed that biofilm growth on the medium could be a major factor in the comparative reduction of surface area between real and synthetic contaminant groundwaters. The modified flyash was found to be a highly sorptive granular material that did not inhibit microbiological activity, however, leaching tests revealed that the medium would fail as a long-term barrier material.

Toward improving CO2 dissociation and conversion to methanol via CO-hydrogenation on Cu(100) surface by introducing embedded Co nanoclusters as promoters: A DFT study

NASA Astrophysics Data System (ADS)

Qiu, Mei; Tao, Huilin; Li, Yali; Li, Yi; Ding, Kaining; Huang, Xin; Chen, Wenkai; Zhang, Yongfan

2018-01-01

The dissociation and hydrogenation of CO2 on Cu(100) surfaces that are modified by introducing Co nanoclusters with different size into the top layer have been investigated using density functional theory method. Our results show that on all surfaces the Co atoms are the sites for the adsorption of CO2, and in the early stage of introducing Co dopant, the chemisorption behavior of CO2 is sensitive to the amount of Co atom. According to the predicted pathways for the dissociation of CO2 to CO, it is interesting that the energy barrier decreases first and then increases as more Co atoms are dispersed on the surface, forming a ;V; shape. The minimum energy barrier of CO2 decomposition is predicted on the Cu(100) surface that contains four Co atoms aggregated together on the top layer, namely Co4/Cu(100) bimetallic surface. The most favorable reaction pathway for the hydrogenation of CO to methanol on such surface is further determined, which follows the sequence of CO* → HCO* → H2CO* → H3CO* → H3COH*, and the rate-limiting step is the hydrogenation of H3CO species with an activation barrier of 106.4 kJ/mol. It is noted that with respect to the pure Cu(100), since more stronger Cosbnd O adsorption bonds are formed on the Co-modified surface, the stability of formaldehyde intermediate is significantly enhanced. Correspondingly, the introducing of Co4 cluster tends to improve the productivity and selectivity towards methanol synthesis on Cu(100) surface.

Barriers to changing dietary behavior.

PubMed

Kapur, Kavita; Kapur, A; Ramachandran, Shobhana; Mohan, V; Aravind, S R; Badgandi, M; Srishyla, M V

2008-01-01

Dietary change requires giving up long established patterns of eating behavior and acquiring new habits. 'Non-compliance' to diet advice may be a result of inability to provide diet self-management training and getting the right messages across to change eating behavior. Using a pre-tested questionnaire based interview, we carried out a study amongst 350 adults (> 20 years) with type 2 diabetes from two metro cities in South India, who had previously received diet advice with the objective to understand perceptions, attitudes and practices, as well as study factors that enhance or reduce compliance to diet advice. Ninety six patients (28%) followed diet for the full duration of diabetes (Group1), 131 (38%) followed diet for a partial duration varying between more than a quarter to three quarters of the total diabetes duration (Group 2) and 115 (34%) did not follow diet advice (Group 3) - followed for a duration less than a quarter of their diabetes duration. Study results show that many factors both patient and health care provider related influence outcomes of dietary advice. Factors that have a positive impact on compliance are - older age, shorter duration, nuclear family, good family support, less busy work life, higher health consciousness, advice given by dietician, more frequent visits to dietician, advice that includes elements to promote overall health not merely control of blood sugar, diet counseling that is easy to understand and use and includes healthy food options, cooking methods, practical guidance to deal with lifestyle issues. We conclude that patient barriers related to life circumstance are mostly non-modifiable, most modifiable barriers are related to behavioural aspect and the inability of the health care provider to provide individualized diet advice and self management training. Efforts must be made to improve counseling skills.

Dl-3-n-butylphthalide protects the blood brain barrier of cerebral infarction by activating the Nrf-2/HO-1 signaling pathway in mice.

PubMed

Zhao, Y-J; Nai, Y; Ma, Q-S; Song, D-J; Ma, Y-B; Zhang, L-H; Mi, L-X

2018-04-01

The aim of this study was to explore whether Dl-3-n-butylphthalide (DBT) could protect blood-brain barrier (BBB) of mice with experimental cerebral infarction and the relevant mechanism. Adult male CD-1 mice were selected as the study objects. The permanent middle cerebral artery occlusion (MCAO) model was prepared by Longa's modified suture-occluded method. The mice were randomly divided into 3 groups: the sham operation group (Sham group), the cerebral infarction model group (CI group) and the DBT (120 mg/kg) intervention group (DBT group). Neurologic function deficits were evaluated by Longa's modified scoring method after 24 h of permanent MCAO. The wet and dry weight method was used for measuring water content in brain tissues. 2% 2,3,5-triphenyltetrazolium chloride (TTC) staining method was applied to determine the volume of cerebral infarction. Changes in the protein and messenger ribonucleic acid (mRNA) expression levels of matrix metallopeptidase 9 (MMP-9), claudin-5, vascular endothelial growth factor (VEGF), glial fibrillary acidic protein (GFAP), NF-E2 related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1) in ischemic brain tissues were detected using immunohistochemistry, Western blotting and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). Ultrastructure changes in BBBs were observed under an electron microscope. DBT improved the neurologic function deficits of mice and reduced the infarction volume of mice with cerebral infarction. DBT alleviated edema and decreased the permeability of BBBs of mice with cerebral infarction. DBT down-regulated the expression of MMP-9 and up-regulated the expression of claudin-5 in brain tissues of mice with cerebral infarction. DBT increased the expressions of VEGF and GFAP. DBT improved the ultrastructure in capillary endothelial cells of BBBs and increased the expressions of Nrf-2 and HO-1. DBT may protect BBB by activating the Nrf-2/HO-1 signaling pathway, thus achieving its protective effect on the brain.

Effect of polyethyleneimine modified graphene on the mechanical and water vapor barrier properties of methyl cellulose composite films.

PubMed

Liu, Hongyu; Liu, Cuiyun; Peng, Shuge; Pan, Bingli; Lu, Chang

2018-02-15

A series of novel methyl cellulose (MC) composite films were prepared using polyethyleneimine reduced graphene oxide (PEI-RGO) as an effective filler for water vapor barrier application. The as-prepared PEI-RGO/MC composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, tensile test and scanning electron microscopy. The experimental and theoretical results exhibited that PEI-RGO was uniformly dispersed in the MC matrix without aggregation and formed an aligned dispersion. The addition of PEI-RGO resulted in an enhanced surface hydrophobicity and a tortuous diffusion pathway for water molecules. Water vapor permeability of PEI-RGO/MC with loading of 3.0% of surface modified graphene was as low as 5.98×10 -11 gmm -2 s -1 Pa -1 . The synergistic effects of enhanced surface hydrophobicity and tortuous diffusion pathway were accounted for the improved water vapor barrier performance of the PEI-RGO/MC composite films. Copyright © 2017 Elsevier Ltd. All rights reserved.

Strongly reduced Ehrlich-Schwoebel barriers at the Cu (111) stepped surface with In and Pb surfactants

NASA Astrophysics Data System (ADS)

Hao, Jialei; Zhang, Lixin

2018-01-01

A surfactant can modify the properties of the surface and induce different mode of epitaxy growth. The atomistic mechanism is not fully understood yet. In this first-principles study, taking Cu homoepitaxy along (111) direction as an example, we show that the distribution of the surfactant atoms on the surface is the key. For In and Pb, they prefer to locate at the step edges and remain isolated. Once the growth is started, the distribution can be further modified by Cu adatoms. The uniquely decorated step edges have much lowered Ehrlich-Schwoebel (ES) barriers than that of the clean edges, thus the two dimensional growth on Cu (111) surface is promoted significantly. On the other hand, for Rh, Ir, and Au, these atoms are not favored at the step edges. The ES barriers can't be affected and these metals are not surfactants. The result is very helpful for searching of the optimal surfactants in metal homoepitaxy.

Modelling the endothelial blood-CNS barriers: a method for the production of robust in vitro models of the rat blood-brain barrier and blood-spinal cord barrier

PubMed Central

2013-01-01

Background Modelling the blood-CNS barriers of the brain and spinal cord in vitro continues to provide a considerable challenge for research studying the passage of large and small molecules in and out of the central nervous system, both within the context of basic biology and for pharmaceutical drug discovery. Although there has been considerable success over the previous two decades in establishing useful in vitro primary endothelial cell cultures from the blood-CNS barriers, no model fully mimics the high electrical resistance, low paracellular permeability and selective influx/efflux characteristics of the in vivo situation. Furthermore, such primary-derived cultures are typically labour-intensive and generate low yields of cells, limiting scope for experimental work. We thus aimed to establish protocols for the high yield isolation and culture of endothelial cells from both rat brain and spinal cord. Our aim was to optimise in vitro conditions for inducing phenotypic characteristics in these cells that were reminiscent of the in vivo situation, such that they developed into tight endothelial barriers suitable for performing investigative biology and permeability studies. Methods Brain and spinal cord tissue was taken from the same rats and used to specifically isolate endothelial cells to reconstitute as in vitro blood-CNS barrier models. Isolated endothelial cells were cultured to expand the cellular yield and then passaged onto cell culture inserts for further investigation. Cell culture conditions were optimised using commercially available reagents and the resulting barrier-forming endothelial monolayers were characterised by functional permeability experiments and in vitro phenotyping by immunocytochemistry and western blotting. Results Using a combination of modified handling techniques and cell culture conditions, we have established and optimised a protocol for the in vitro culture of brain and, for the first time in rat, spinal cord endothelial cells. High yields of both CNS endothelial cell types can be obtained, and these can be passaged onto large numbers of cell culture inserts for in vitro permeability studies. The passaged brain and spinal cord endothelial cells are pure and express endothelial markers, tight junction proteins and intracellular transport machinery. Further, both models exhibit tight, functional barrier characteristics that are discriminating against large and small molecules in permeability assays and show functional expression of the pharmaceutically important P-gp efflux transporter. Conclusions Our techniques allow the provision of high yields of robust sister cultures of endothelial cells that accurately model the blood-CNS barriers in vitro. These models are ideally suited for use in studying the biology of the blood-brain barrier and blood-spinal cord barrier in vitro and for pre-clinical drug discovery. PMID:23773766

Modifiable barriers to leisure-time physical activity during pregnancy: a qualitative study investigating first time mother's views and experiences.

PubMed

Connelly, Megan; Brown, Helen; van der Pligt, Paige; Teychenne, Megan

2015-04-22

Evidence suggests physical activity often declines during pregnancy, however explanations for the decline are not well understood. The aim of this study was to identify modifiable barriers to leisure-time physical activity among women who did not meet physical activity guidelines during pregnancy. Analyses were based on data from 133 mothers (~3-months postpartum) who were recruited from the Melbourne InFANT Extend study (2012/2013). Women completed a self-report survey at baseline in which they reported their leisure-time physical activity levels during pregnancy as well provided an open-ended written response regarding the key barriers that they perceived prevented them from meeting the physical activity guidelines during their pregnancy. Thematic analyses were conducted to identify key themes. The qualitative data revealed six themes relating to the barriers of leisure-time physical activity during pregnancy. These included work-related factors (most commonly reported), tiredness, pregnancy-related symptoms, being active but not meeting the guidelines, lack of motivation, and a lack of knowledge of recommendations. Considering work-related barriers were suggested to be key factors to preventing women from meeting the physical activity guidelines during pregnancy, workplace interventions aimed at providing time management skills along with supporting physical activity programs for pregnant workers should be considered. Such interventions should also incorporate knowledge and education components, providing advice for undertaking leisure-time physical activity during pregnancy.

Position of Proline Mediates the Reactivity of S-Palmitoylation.

PubMed

Khanal, Neelam; Pejaver, Vikas; Li, Zhiyu; Radivojac, Predrag; Clemmer, David E; Mukhopadhyay, Suchetana

2015-11-20

Palmitoylation, a post-translational modification in which a saturated 16-carbon chain is added predominantly to a cysteine residue, participates in various biological functions. The position of proline relative to other residues being post-translationally modified has been previously reported as being important. We determined that proline is statistically enriched around cysteines known to be S-palmitoylated. The goal of this work was to determine how the position of proline influences the palmitoylation of the cysteine residue. We established a mass spectrometry-based approach to investigate time- and temperature-dependent kinetics of autopalmitoylation in vitro and to derive the thermodynamic parameters of the transition state associated with palmitoylation; to the best of our knowledge, our work is the first to study the kinetics and activation properties of the palmitoylation process. We then used these thermochemical parameters to determine if the position of proline relative to the modified cysteine is important for palmitoylation. Our results show that peptides with proline at the -1 position of cysteine in their sequence (PC) have lower enthalpic barriers and higher entropic barriers in comparison to the same peptides with proline at the +1 position of cysteine (CP); interestingly, the free-energy barriers for both pairs are almost identical. Molecular dynamics studies demonstrate that the flexibility of the cysteine backbone in the PC-containing peptide when compared to the CP-containing peptide explains the increased entropic barrier and decreased enthalpic barrier observed experimentally.

Perspectives on family planning services among adolescents at a Boston community health center.

PubMed

Johnson, Katherine M; Dodge, Laura E; Hacker, Michele R; Ricciotti, Hope A

2015-04-01

The aim of this project was to investigate adolescent perspectives on family planning services at a community-health center, with the intent to inform health center programs aimed at stemming the adolescent pregnancy rate. This project was cross-sectional and employed mixed methods, including surveys and interviews, for the purposes of quality improvement. The project was conducted in the obstetrics and gynecology clinic at an urban community health center in Boston. Twenty adolescent females (age 16-20) who used services at the health center. Participants were individually interviewed to assess perspectives on family planning services and to identify major influences on methods of pregnancy prevention. Major themes were categorized into contraceptive usage, reproductive health knowledge, adult influence and communication, barriers to contraceptive care and expectations of a family planning clinic. All participants were sexually active and 80% had experienced pregnancy. Reproductive health knowledge was variable and in many cases limited. Concern about disapproval was a prominent barrier to going to a clinician for contraception or advice and parents were not often involved in the initial contraception discussion. Other barriers to use of contraception included forgetting to use the methods and fear of side effects. We identified several potentially modifiable factors, including lack of knowledge, concern for provider disapproval and fear of side effects that may limit effective use of family planning services by adolescents. Further attention should be paid to these factors in designing and improving youth-friendly services in ob-gyn clinics. Copyright © 2015 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Thermoelectric properties of nano-granular indium-tin-oxide within modified electron filtering model with chemisorption-type potential barriers

NASA Astrophysics Data System (ADS)

Brinzari, V.; Nika, D. L.; Damaskin, I.; Cho, B. K.; Korotcenkov, G.

2016-07-01

In this work, an approach to the numerical study of the thermoelectric parameters of nanoscale indium tin oxide (ITO, Sn content<10 at%) based on an electron filtering model (EFM) was developed. Potential barriers at grain boundaries were assumed to be responsible for a filtering effect. In the case of the dominant inelastic scattering of electrons, the maximal distance between potential barriers was limited in this modified model. The algorithm for such characteristic length calculation was proposed, and its value was evaluated for ITO. In addition, the contributions of different scattering mechanisms (SMs) in electron transport were examined. It was confirmed that in bulk ITO, the scattering on polar optical phonons (POPs) and ionized impurities dominates, limiting electron transport. In the framework of the filtering model, the basic thermoelectric parameters (i.e., electrical conductivity, mobility, Seebeck coefficient, and power factor (PF)) were calculated for ITO in the temperature range of 100-500 °C as a function of potential barrier height. The results demonstrated a sufficient rise of the Seebeck coefficient with an increase in barrier height and specific behavior of PF. It was found that PF is very sensitive to barrier height, and at its optimal value for granular ITO, it may exceed the PF for bulk ITO by 3-5 times. The PF maximum was achieved by band bending, slightly exceeding Fermi energy. The nature of surface potential barriers in nano-granular ITO with specific grains is due to the oxygen chemisorption effect, and this can be observed despite of the degeneracy of the conduction band (CB). This hypothesis and the corresponding calculations are in good agreement with recent experimental studies [Brinzari et al. Thin Solid Films 552 (2014) 225].

A Contextual Overview of the Modified Consent Decree in the Los Angeles Unified School District

ERIC Educational Resources Information Center

Weintraub, Frederick J.; Myers, Robert M.; Hehir, Thomas; Jaque-Anton, Donnalyn

2008-01-01

Since 1996, the Los Angeles Unified School District (LAUSD), located in Southern California, has been under a federal court consent decree requiring compliance with laws pertaining to the delivery of special education services and the elimination of architectural barriers in schools. In 2003, the consent decree was modified, creating…

Biological intrusion of low-level-waste trench covers

NASA Astrophysics Data System (ADS)

Hakonson, T. E.; Gladney, E. S.

The long-term integrity of low-level waste shallow land burialsites is dependent on the interaction of physical, chemical, and biological factors that modify the waste containment system. The need to consider biological processes as being potentially important in reducing the integrity of waste burial site cover treatment is demonstrated. One approach to limiting biological intrusion through the waste cover is to apply a barrier within the profile to limit root and animal penetration with depth. Experiments in the Los Alamos Experimental Engineered Test Facility were initiated to develop and evaluate biological barriers that are effective in minimizing intrusion into waste trenches. The experiments that are described employ four different candidate barrier materials of geologic origin. Experimental variables that will be evaluated, in addition to barrier type, are barrier depth and sil overburden depth.

Biomaterials for periodontal regeneration

PubMed Central

Shue, Li; Yufeng, Zhang; Mony, Ullas

2012-01-01

Periodontal disease is characterized by the destruction of periodontal tissues. Various methods of regenerative periodontal therapy, including the use of barrier membranes, bone replacement grafts, growth factors and the combination of these procedures have been investigated. The development of biomaterials for tissue engineering has considerably improved the available treatment options above. They fall into two broad classes: ceramics and polymers. The available ceramic-based materials include calcium phosphate (eg, tricalcium phosphate and hydroxyapatite), calcium sulfate and bioactive glass. The bioactive glass bonds to the bone with the formation of a layer of carbonated hydroxyapatite in situ. The natural polymers include modified polysaccharides (eg, chitosan,) and polypeptides (collagen and gelatin). Synthetic polymers [eg, poly(glycolic acid), poly(L-lactic acid)] provide a platform for exhibiting the biomechanical properties of scaffolds in tissue engineering. The materials usually work as osteogenic, osteoconductive and osteoinductive scaffolds. Polymers are more widely used as a barrier material in guided tissue regeneration (GTR). They are shown to exclude epithelial downgrowth and allow periodontal ligament and alveolar bone cells to repopulate the defect. An attempt to overcome the problems related to a collapse of the barrier membrane in GTR or epithelial downgrowth is the use of a combination of barrier membranes and grafting materials. This article reviews various biomaterials including scaffolds and membranes used for periodontal treatment and their impacts on the experimental or clinical management of periodontal defect. PMID:23507891

Potential in-class strategies to increase children's vegetable consumption.

PubMed

Sharp, Gemma; Pettigrew, Simone; Wright, Shannon; Pratt, Iain S; Blane, Sally; Biagioni, Nicole

2017-06-01

The Crunch&Sip programme is a school-based nutrition initiative designed to increase the fruit, vegetable and water intakes of primary-school children. In recognition of the notable deficits in children's vegetable consumption, the present study explored the receptivity of school staff to a realignment of the Crunch&Sip programme to feature a primary focus on vegetable consumption. This involved investigating school staff members' perceptions of relevant barriers, motivators and facilitators. A multi-method approach was adopted that involved four focus groups and a survey (administered in paper and online formats) containing a mixture of open- and closed-ended items. Western Australia. Staff from Western Australian schools participated in the focus groups (n 37) and survey (n 620). School staff were strongly supportive of modifying the Crunch&Sip programme to focus primarily on children's vegetable consumption and this was generally considered to be a feasible change to implement. Possible barriers identified included children's taste preferences and a perceived lack of parental support. Suggested strategies to overcome these barriers were education sessions for parents and children, teachers modelling vegetable consumption for their students and integrating vegetable-related topics into the school curriculum. School staff are likely to support the introduction of school-based nutrition programmes that specifically encourage the consumption of vegetables. Potential barriers may be overcome through strategies to engage parents and children.

Evaluation of smallpox vaccines using variola neutralization

PubMed Central

Damon, Inger K.; Davidson, Whitni B.; Hughes, Christine M.; Olson, Victoria A.; Smith, Scott K.; Holman, Robert C.; Frey, Sharon E.; Newman, Frances; Belshe, Robert B.; Yan, Lihan; Karem, Kevin

2009-01-01

The search for a ‘third’-generation smallpox vaccine has resulted in the development and characterization of several vaccine candidates. A significant barrier to acceptance is the absence of challenge models showing induction of correlates of protective immunity against variola virus. In this light, virus neutralization provides one of few experimental methods to show specific ‘in vitro’ activity of vaccines against variola virus. Here, we provide characterization of the ability of a modified vaccinia virus Ankara vaccine to induce variola virus-neutralizing antibodies, and we provide comparison with the neutralization elicited by standard Dryvax vaccination. PMID:19339477

A Modified Suture Bridge Technique for Application With Bone Anchors in Foot and Ankle Surgery.

PubMed

Walters, Jeremy; Correa, Christopher; Moss, Mark

2015-01-01

We present a suture bridge technique for reattachment of tendon or ligament to bone for use in foot and ankle surgery. The method is a simple, strong, and reproducible technique that could decrease the risk of irritation of the overlying cutaneous barrier and minimizes the likelihood of tendon strangulation when combined with soft tissue bone anchors. The present report serves as a guide to the use of this suture technique for reattachment of the Achilles tendon. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Enhancing antimicrobial activity of TiO2/Ti by torularhodin bioinspired surface modification.

PubMed

Ungureanu, Camelia; Dumitriu, Cristina; Popescu, Simona; Enculescu, Monica; Tofan, Vlad; Popescu, Marian; Pirvu, Cristian

2016-02-01

Implant-associated infections are a major cause of morbidity and mortality. This study was performed using titanium samples coated by anodization with a titanium dioxide (TiO2) shielded nanotube layer. TiO2/Ti surface was modified by simple immersion in torularhodin solution and by using a mussel-inspired method based on polydopamine as bio adhesive for torularhodin immobilization. SEM analysis revealed tubular microstructures of torularhodin and the PDA ability to function as a catchy anchor between torularhodin and TiO2 surface. Corrosion resistance was associated with TiO2 barrier oxide layer and nano-organized oxide layer and the torularhodin surface modification does not bring significant changes in resistance of the oxide layer. Our results demonstrated that the torularhodin modified TiO2/Ti surface could effectively prevent adhesion and proliferation of Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and Pseudomonas aeruginosa. The new modified titanium surface showed good biocompatibility and well-behaved haemocompatibility. This biomaterial with enhanced antimicrobial activity holds great potential for future biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Perceptions of the usefulness of external support to immunization coverage in Chad: an analysis of the GAVI-Alliance cash-based support

PubMed Central

Ferrinho, Paulo; Dramé, Mohammed; Tumusiime, Prosper

2013-01-01

Introduction Chad is one of the countries supported by the GAVI-Alliance that remains with unsatisfactory vaccination coverage. This paper tries to understand the main barriers to better coverage. Methods These barriers were categorised as up or downstream against the health system building blocks as proposed by WHO and compared with barriers and activities identified by the country in its health system's strengthening grant proposal as approved by the GAVI Alliance in 2007. Data were collected using a modified Delphi system and by analysis of grant and annual report documents. Results Most of the activities anticipated under the GAVI health system's strengthening proposal are activities targeting downstream barriers (the neglect of upstream issues is of major importance in a decentralised state like Chad) and aligned with, not complementary to, immunization services strengthening activities. Further, both set of cash grants are blind to important recommendations such as the need to address barriers at the level of leadership and governance and at the level of the financing system and also about initiatives to promote community demand of vaccination services. Conclusion In Chad slow vaccination progress is aggravated by several contextual barriers: the size of the country, the low population density, the nomadic nature of a significant part of its peoples, the recent civil war, associated with civil unrest and political instability and its geographical localization. In this situation it would be important to sustain downstream operations (the major focus of the ISS grant) while taking a long term view of the needs of the health system. The GAVI effectively supports downstream operations, but neglects the long term view. PMID:24106572

Barriers to accessing biologic treatment for rheumatoid arthritis in Greece: the unseen impact of the fiscal crisis--the Health Outcomes Patient Environment (HOPE) study.

PubMed

Souliotis, Kyriakos; Papageorgiou, Manto; Politi, Anastasia; Ioakeimidis, Dimitrios; Sidiropoulos, Prodromos

2014-01-01

The latest regulatory change in the distribution system of biologic disease-modifying, antirheumatic drugs limited their sale only through the designated pharmacies of the National Organization for Healthcare Services Provision (EOPYY) or the National Health System (NHS) hospitals, adding to the complexity of access to effective treatment for rheumatoid arthritis (RA) in Greece. The aim of this paper was to assess the barriers to access RA treatment, by recording patients', rheumatologists' and EOPYY pharmacists' experiences. One twenty-three patients, 12 rheumatologists and 27 pharmacists from Athens and other urban areas in Greece participated in the study. Three types of standardized questionnaires were used to elicit information from each group of respondents using the method of personal interview for patients and the method of postal survey for doctors and pharmacists. During the last year, 26% of patients encountered problems in accessing their rheumatologist and 49% of patients experienced difficulties in accessing their medication. Ninety-two percent of rheumatologists and 96% of pharmacists confirmed that patients experience difficulties in accessing RA medication. The most commonly reported reasons for reduced access to medical treatment were travel difficulties and long distance from doctor's clinic, as well as delays in booking an appointment. The most frequently reported barriers to access pharmaceutical treatment were difficulties in the prescription process, distance from EOPYY pharmacies and medicine shortages in NHS hospitals. The study showed that RA patients are facing increased barriers to access timely and effective treatment. Redesign of the current system of distribution ensuring the operation of additional points of sale is deemed necessary.

A photoemission moments model using density functional and transfer matrix methods applied to coating layers on surfaces: Theory

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

Jensen, Kevin L.; Finkenstadt, Daniel; Shabaev, Andrew

Recent experimental measurements of a bulk material covered with a small number of graphene layers reported by Yamaguchi et al. [NPJ 2D Mater. Appl. 1, 12 (2017)] (on bialkali) and Liu et al.[Appl. Phys. Lett. 110, 041607 (2017)] (on copper) and the needs of emission models in beam optics codes have lead to substantial changes in a Moments model of photoemission. The changes account for (i) a barrier profile and density of states factor based on density functional theory (DFT) evaluations, (ii) a Drude-Lorentz model of the optical constants and laser penetration depth, and (iii) a transmission probability evaluated bymore » an Airy Transfer Matrix Approach. Importantly, the DFT results lead to a surface barrier profile of a shape similar to both resonant barriers and reflectionless wells: the associated quantum mechanical transmission probabilities are shown to be comparable to those recently required to enable the Moments (and Three Step) model to match experimental data but for reasons very different than the assumption by conventional wisdom that a barrier is responsible. The substantial modifications of the Moments model components, motivated by computational materials methods, are developed. The results prepare the Moments model for use in treating heterostructures and discrete energy level systems (e.g., quantum dots) proposed for decoupling the opposing metrics of performance that undermine the performance of advanced light sources like the x-ray Free Electron Laser. The consequences of the modified components on quan-tum yield, emittance, and emission models needed by beam optics codes are discussed. Published by AIP Publishing. https://doi.org/10.1063/1.5008600« less

A photoemission moments model using density functional and transfer matrix methods applied to coating layers on surfaces: Theory

DOE PAGES

Jensen, Kevin L.; Finkenstadt, Daniel; Shabaev, Andrew; ...

2018-01-28

Recent experimental measurements of a bulk material covered with a small number of graphene layers reported by Yamaguchi et al. [NPJ 2D Mater. Appl. 1, 12 (2017)] (on bialkali) and Liu et al.[Appl. Phys. Lett. 110, 041607 (2017)] (on copper) and the needs of emission models in beam optics codes have lead to substantial changes in a Moments model of photoemission. The changes account for (i) a barrier profile and density of states factor based on density functional theory (DFT) evaluations, (ii) a Drude-Lorentz model of the optical constants and laser penetration depth, and (iii) a transmission probability evaluated bymore » an Airy Transfer Matrix Approach. Importantly, the DFT results lead to a surface barrier profile of a shape similar to both resonant barriers and reflectionless wells: the associated quantum mechanical transmission probabilities are shown to be comparable to those recently required to enable the Moments (and Three Step) model to match experimental data but for reasons very different than the assumption by conventional wisdom that a barrier is responsible. The substantial modifications of the Moments model components, motivated by computational materials methods, are developed. The results prepare the Moments model for use in treating heterostructures and discrete energy level systems (e.g., quantum dots) proposed for decoupling the opposing metrics of performance that undermine the performance of advanced light sources like the x-ray Free Electron Laser. The consequences of the modified components on quan-tum yield, emittance, and emission models needed by beam optics codes are discussed. Published by AIP Publishing. https://doi.org/10.1063/1.5008600« less

The expert's guide to mealtime interventions - A Delphi method survey.

PubMed

Conchin, Simone; Carey, Sharon

2017-09-27

Prevalence of malnutrition and a myriad of barriers to adequate oral diet in hospitalised patients warrants further investment to improve the patient mealtime experience. The aim of this study was to explore barriers and enablers to implementing effective mealtime interventions and develop a process framework to guide clinicians and researchers in the area. Potential experts in the area of hospital mealtime intervention were identified as having published in this field of work within the Australasian setting. Further information was sought by email and telephone communication on professional background; research experience; interest; and capacity to participate. Recruited participants were surveyed using a modified Delphi method to establish opinion and experience in the area of mealtime interventions. Results were collated and content was coded using a thematic analysis approach by the primary researcher and two additional reviewers. Thirty-two Australian authors in the area of mealtime interventions within the hospital environment were identified from publication. Twenty-one participants were able to be contacted and nineteen of these consented to enrol in the study. Participants included those from a dietetic (n = 14), nursing (n = 4) and medical (n = 1) background. Participants were deemed to have expert knowledge if they had significant involvement in the published research and demonstrated a deep level of understanding of hospital mealtime interventions. All participants provided key insights into barriers to oral intake in the hospital environment and suggestions for interventions to address these barriers. From the survey, an eight step framework to guide mealtime interventions was developed. Hospital mealtime interventions are complex processes. Interventions should be implemented after careful consideration of the local context and baseline data; and tailored to address barriers. Roles and responsibilities for nutrition care should be clear and consistent. Implementation planning is recommended to ensure that an ongoing process is in place to engage executive support and staff involvement, foster project team resilience and ensure sustainability of interventions. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Remediation of arsenic-contaminated groundwater using media-injected permeable reactive barriers with a modified montmorillonite: sand tank studies.

PubMed

Luo, Ximing; Liu, Haifei; Huang, Guoxin; Li, Ye; Zhao, Yan; Li, Xu

2016-01-01

A modified montmorillonite (MMT) was prepared using an acid activation-sodium activation-iron oxide coating method to improve the adsorption capacities of natural MMTs. For MMT, its interlamellar distance increased from 12.29 to 13.36 Å, and goethite (α-FeOOH) was intercalated into its clay layers. Two novel media-injected permeable reactive barrier (MI-PRB) configurations were proposed for removing arsenic from groundwater. Sand tank experiments were conducted to investigate the performance of the two MI-PRBs: Tank A was filled with quartz sand. Tank B was packed with quartz sand and zero-valent iron (ZVI) in series, and the MMT slurry was respectively injected into them to form reactive zones. The results showed that for tank A, total arsenic (TA) removal of 98.57% was attained within the first 60 mm and subsequently descended slowly to 88.84% at the outlet. For tank B, a similar spatial variation trend was observed in the quartz sand layer, and subsequently, TA removal increased to ≥99.80% in the ZVI layer. TA removal by MMT mainly depended on both surface adsorption and electrostatic adhesion. TA removal by ZVI mainly relied on coagulation/precipitation and adsorption during the iron corrosion. The two MI-PRBs are feasible alternatives for in situ remediation of groundwater with elevated As levels.

Methodology for calculating the volume of condensate droplets on topographically modified, microgrooved surfaces.

PubMed

Sommers, A D

2011-05-03

Liquid droplets on micropatterned surfaces consisting of parallel grooves tens of micrometers in width and depth are considered, and a method for calculating the droplet volume on these surfaces is presented. This model, which utilizes the elongated and parallel-sided nature of droplets condensed on these microgrooved surfaces, requires inputs from two droplet images at ϕ = 0° and ϕ = 90°--namely, the droplet major axis, minor axis, height, and two contact angles. In this method, a circular cross-sectional area is extruded the length of the droplet where the chord of the extruded circle is fixed by the width of the droplet. The maximum apparent contact angle is assumed to occur along the side of the droplet because of the surface energy barrier to wetting imposed by the grooves--a behavior that was observed experimentally. When applied to water droplets condensed onto a microgrooved aluminum surface, this method was shown to calculate the actual droplet volume to within 10% for 88% of the droplets analyzed. This method is useful for estimating the volume of retained droplets on topographically modified, anisotropic surfaces where both heat and mass transfer occur and the surface microchannels are aligned parallel to gravity to assist in condensate drainage.

A novel power harmonic analysis method based on Nuttall-Kaiser combination window double spectrum interpolated FFT algorithm

NASA Astrophysics Data System (ADS)

Jin, Tao; Chen, Yiyang; Flesch, Rodolfo C. C.

2017-11-01

Harmonics pose a great threat to safe and economical operation of power grids. Therefore, it is critical to detect harmonic parameters accurately to design harmonic compensation equipment. The fast Fourier transform (FFT) is widely used for electrical popular power harmonics analysis. However, the barrier effect produced by the algorithm itself and spectrum leakage caused by asynchronous sampling often affects the harmonic analysis accuracy. This paper examines a new approach for harmonic analysis based on deducing the modifier formulas of frequency, phase angle, and amplitude, utilizing the Nuttall-Kaiser window double spectrum line interpolation method, which overcomes the shortcomings in traditional FFT harmonic calculations. The proposed approach is verified numerically and experimentally to be accurate and reliable.

Analytical study on the suitability of using bentonite coated gravel as a landfill liner material

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

Roberts, Anel A.; Shimaoka, Takayuki

2008-12-15

This study investigates the feasibility of using bentonite coated gravel (BCG) as a liner material for waste landfills. BCG has proven to be a very effective capping material/method for the remediation of contaminated sediments in aquatic environments. The concept of BCG is similar to that of peanuts/almonds covered with chocolate; each aggregate particle has been covered with the clayey material. Laboratory tests were aimed at evaluating regulated and non-regulated factors for liner materials, i.e., permeability and strength. Tests included X-ray diffraction, methylene blue absorption, compaction, free swelling, permeability, 1D consolidation, triaxial compression and cone penetration. The compactive efforts used formore » this study were the reduced Proctor, standard Proctor, intermediate Proctor, modified Proctor and super modified Proctor. The compactive energy corresponding to each effort, respectively, is as follows: 355.5, 592.3, 1196.3, 2693.3, and 5386.4 kJ/m{sup 3}. Results revealed that even though aggregate content represents 70% of the weight of the material, hydraulic conductivities as low as 6 x 10{sup -10} cm/s can be achieved when proper compactive efforts are used. Compressibility is very low for this material even at low (or no) compactive efforts. Results also demonstrated how higher compactive efforts can lower the permeability of BCG; however, over-compaction creates fractures in the aggregate core of BCG that could increase permeability. Moreover, higher compactive efforts create higher swelling pressures that could compromise the performance of a barrier constructed using BCG. As a result of this study, moderate compactive efforts, i.e., intermediate Proctor or modified Proctor, are recommended for constructing a BCG barrier. Using moderate compactive efforts, very low hydraulic conductivities, good workability and good trafficability are easily attainable.« less

Analytical study on the suitability of using bentonite coated gravel as a landfill liner material.

PubMed

Roberts, Anel A; Shimaoka, Takayuki

2008-12-01

This study investigates the feasibility of using bentonite coated gravel (BCG) as a liner material for waste landfills. BCG has proven to be a very effective capping material/method for the remediation of contaminated sediments in aquatic environments. The concept of BCG is similar to that of peanuts/almonds covered with chocolate; each aggregate particle has been covered with the clayey material. Laboratory tests were aimed at evaluating regulated and non-regulated factors for liner materials, i.e., permeability and strength. Tests included X-ray diffraction, methylene blue absorption, compaction, free swelling, permeability, 1D consolidation, triaxial compression and cone penetration. The compactive efforts used for this study were the reduced Proctor, standard Proctor, intermediate Proctor, modified Proctor and super modified Proctor. The compactive energy corresponding to each effort, respectively, is as follows: 355.5, 592.3, 1196.3, 2693.3, and 5386.4 kJ/m(3). Results revealed that even though aggregate content represents 70% of the weight of the material, hydraulic conductivities as low as 6 x 10(-10)cm/s can be achieved when proper compactive efforts are used. Compressibility is very low for this material even at low (or no) compactive efforts. Results also demonstrated how higher compactive efforts can lower the permeability of BCG; however, over-compaction creates fractures in the aggregate core of BCG that could increase permeability. Moreover, higher compactive efforts create higher swelling pressures that could compromise the performance of a barrier constructed using BCG. As a result of this study, moderate compactive efforts, i.e., intermediate Proctor or modified Proctor, are recommended for constructing a BCG barrier. Using moderate compactive efforts, very low hydraulic conductivities, good workability and good trafficability are easily attainable.

Field Techniques: Atlantic Barrier System. Field Guidebook. National Association of Geology Teachers Eastern Section Annual Field Conference (Lewes, Delaware, April 26-29, 1984).

ERIC Educational Resources Information Center

O'Connor, James V., Ed.; Tormey, Brian B., Ed.

The Atlantic barrier system is used as a focal point in this manual of field exercises. A collection of activities and posed questions provide students with opportunities to develop skills basic to the development of sound field techniques. Investigations can be adapted and modified by teachers to specific subject areas and developmental needs.…

A seesaw-type approach for enhancing nonlinear energy harvesting

NASA Astrophysics Data System (ADS)

Deng, Huaxia; Wang, Zhemin; Du, Yu; Zhang, Jin; Ma, Mengchao; Zhong, Xiang

2018-05-01

Harvesting sustainable mechanical energy is the ultimate objective of nonlinear energy harvesters. However, overcoming potential barriers, especially without the use of extra excitations, poses a great challenge for the development of nonlinear generators. In contrast to the existing methods, which typically modify the barrier height or utilize additional excitations, this letter proposes a seesaw-type approach to facilitate escape from potential wells by transfer of internal energy, even under low-intensity excitation. This approach is adopted in the design of a seesaw-type nonlinear piezoelectric energy harvester and the energy transfer process is analyzed by deriving expressions for the energy to reveal the working mechanism. Comparison experiments demonstrate that this approach improves energy harvesting in terms of an increase in the working frequency bandwidth by a factor of 60.14 and an increase in the maximum output voltage by a factor of 5.1. Moreover, the output power is increased by a factor of 51.3, which indicates that this approach significantly improves energy collection efficiency. This seesaw-type approach provides a welcome boost to the development of renewable energy collection methods by improving the efficiency of harvesting of low-intensity ambient mechanical energy.

Spatial inhomogeneous barrier heights at graphene/semiconductor Schottky junctions

NASA Astrophysics Data System (ADS)

Tomer, Dushyant

Graphene, a semimetal with linear energy dispersion, forms Schottky junction when interfaced with a semiconductor. This dissertation presents temperature dependent current-voltage and scanning tunneling microscopy/spectroscopy (STM/S) measurements performed on graphene Schottky junctions formed with both three and two dimensional semiconductors. To fabricate Schottky junctions, we transfer chemical vapor deposited monolayer graphene onto Si- and C-face SiC, Si, GaAs and MoS2 semiconducting substrates using polymer assisted chemical method. We observe three main type of intrinsic spatial inhomogeneities, graphene ripples, ridges and semiconductor steps in STM imaging that can exist at graphene/semiconductor junctions. Tunneling spectroscopy measurements reveal fluctuations in graphene Dirac point position, which is directly related to the Schottky barrier height. We find a direct correlation of Dirac point variation with the topographic undulations of graphene ripples at the graphene/SiC junction. However, no such correlation is established at graphene/Si and Graphene/GaAs junctions and Dirac point variations are attributed to surface states and trapped charges at the interface. In addition to graphene ripples and ridges, we also observe atomic scale moire patterns at graphene/MoS2 junction due to van der Waals interaction at the interface. Periodic topographic modulations due to moire pattern do not lead to local variation in graphene Dirac point, indicating that moire pattern does not contribute to fluctuations in electronic properties of the heterojunction. We perform temperature dependent current-voltage measurements to investigate the impact of topographic inhomogeneities on electrical properties of the Schottky junctions. We observe temperature dependence in junction parameters, such as Schottky barrier height and ideality factor, for all types of Schottky junctions in forward bias measurements. Standard thermionic emission theory which assumes a perfect smooth interface fails to explain such behavior, hence, we apply a modified emission theory with Gaussian distribution of Schottky barrier heights. The modified theory, applicable to inhomogeneous interfaces, explains the temperature dependent behavior of our Schottky junctions and gives a temperature independent mean barrier height. We attribute the inhomogeneous barrier height to the presence of graphene ripples and ridges in case of SiC and MoS2 while surface states and trapped charges at the interface is dominating in Si and GaAs. Additionally, we observe bias dependent current and barrier height in reverse bias regime also for all Schottky junctions. To explain such behavior, we consider two types of reverse bias conduction mechanisms; Poole-Frenkel and Schottky emission. We find that Poole-Frenkel emission explains the characteristics of graphene/SiC junctions very well. However, both the mechanism fails to interpret the behavior of graphene/Si and graphene/GaAs Schottky junctions. These findings provide insight into the fundamental physics at the interface of graphene/semiconductor junctions.

Assessment of the physical, mechanical, and moisture-retention properties of pullulan-based ternary co-blended films.

PubMed

Pan, Hongyang; Jiang, Bo; Chen, Jie; Jin, Zhengyu

2014-11-04

Multi-component substances made through direct blending or blending with co-drying can form films on the surfaces of intermediate moisture foods (IMFs), which help retain moisture and protect food texture and flavor. An IMF film system based on pullulan, with glycerol serving as the plasticizer, was studied using alginate and four different types of polysaccharides (propyleneglycol alginate, pectin, carrageenan, and aloe polysaccharide) as the blend-modified substances. The physical, mechanical, color, transparency, and moisture-retention properties of the co-blended films with the polysaccharides were assessed. A new formula was established for the average moisture retention property, water barrier, tensile strength, elongation at break, and oxygen barrier property of the ternary co-blended films using the Design Expert software. The new model established for moisture content measurement used an indirect method of film formation on food surfaces by humectants, which should expedite model validation and allow a better comprehension of moisture transfer through edible films. Copyright © 2014 Elsevier Ltd. All rights reserved.

The role of probe oxide in local surface conductivity measurements

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

Barnett, C. J.; Kryvchenkova, O.; Wilson, L. S. J.

2015-05-07

Local probe methods can be used to measure nanoscale surface conductivity, but some techniques including nanoscale four point probe rely on at least two of the probes forming the same low resistivity non-rectifying contact to the sample. Here, the role of probe shank oxide has been examined by carrying out contact and non-contact I V measurements on GaAs when the probe oxide has been controllably reduced, both experimentally and in simulation. In contact, the barrier height is pinned but the barrier shape changes with probe shank oxide dimensions. In non-contact measurements, the oxide modifies the electrostatic interaction inducing a quantummore » dot that alters the tunneling behavior. For both, the contact resistance change is dependent on polarity, which violates the assumption required for four point probe to remove probe contact resistance from the measured conductivity. This has implications for all nanoscale surface probe measurements and macroscopic four point probe, both in air and vacuum, where the role of probe oxide contamination is not well understood.« less

Exploring perceived barriers, drivers, impacts and the need for evaluation of public involvement in health and social care research: a modified Delphi study

PubMed Central

Snape, D; Kirkham, J; Britten, N; Froggatt, K; Gradinger, F; Lobban, F; Popay, Jennie; Wyatt, K; Jacoby, Ann

2014-01-01

Objective To explore areas of consensus and conflict in relation to perceived public involvement (PI) barriers and drivers, perceived impacts of PI and ways of evaluating PI approaches in health and social care research. Background Internationally and within the UK the recognition of potential benefits of PI in health and social care research is gathering momentum and PI is increasingly identified by organisations as a prerequisite for funding. However, there is relatively little examination of the impacts of PI and how those impacts might be measured. Design Mixed method, three-phase, modified Delphi technique, conducted as part of a larger MRC multiphase project. Sample Clinical and non-clinical academics, members of the public, research managers, commissioners and funders. Findings This study found high levels of consensus about the most important barriers and drivers to PI. There was acknowledgement that tokenism was common in relation to PI; and strong support for the view that demonstrating the impacts and value of PI was made more difficult by tokenistic practice. PI was seen as having intrinsic value; nonetheless, there was clear support for the importance of evaluating its impact. Research team cohesion and appropriate resources were considered essential to effective PI implementation. Panellists agreed that PI can be challenging, but can be facilitated by clear guidance, together with models of good practice and measurable standards. Conclusions This study is the first to present empirical evidence of the opinions voiced by key stakeholders on areas of consensus and conflict in relation to perceived PI barriers and drivers, perceived impacts of PI and the need to evaluate PI. As such it further contributes to debate around best practice in PI, the potential for tokenism and how best to evaluate the impacts of PI. These findings have been used in the development of the Public Involvement Impact Assessment Framework (PiiAF), an online resource which offers guidance to researchers and members of the public involved in the PI process. PMID:24939808

Investigation of gas surface interactions at self-assembled silicon surfaces acting as gas sensors

NASA Astrophysics Data System (ADS)

Narducci, Dario; Bernardinello, Patrizia; Oldani, Matteo

2003-05-01

This paper reports the results of an investigation aimed at using self-assembled monolayers to modify the supramolecular interactions between Si surfaces and gaseous molecules. The specific goal is that of employing molecularly imprinted silicon surfaces to develop a new class of chemical sensors capable to detect species with enhanced selectivity. Single-crystal p-type (0 0 1) silicon has been modified by grafting organic molecules onto its surface by using wet chemistry synthetic methods. Silicon has been activated toward nucleophilic attack by brominating its surface using a modified version of the purple etch, and aromatic fragments have been bonded through the formation of direct Si-C bonds onto it using Grignard reagents or lithium aryl species. Formation of self-assembled monolayers (SAMs) was verified by using vibrational spectroscopy. Porous metal-SAM-Si diodes have been successfully tested as resistive chemical sensors toward NO x, SO x, CO, NH 3 and methane. Current-voltage characteristics measured at different gas compositions showed that the mechanism of surface electron density modulation involves a modification of the junction barrier height upon gas adsorption. Quantum-mechanical simulations of the interaction mechanism were carried out using different computational methods to support such an interaction mechanism. The results obtained appear to open up new relevant applications of the SAM techniques in the area of gas sensing.

Performance of Poly(lactic acid) Surface Modified Films for Food Packaging Application

PubMed Central

Dalla Rosa, Marco; Iordanskii, Alexey L.

2017-01-01

Five Poly(lactic acid) (PLA) film samples were analyzed to study the gas barrier behavior, thermal stability and mechanical performance for food packaging application. O2, CO2, N2, N2O, and C2H4 pure gases; Air; and Modified Atmosphere (MA, 79% N2O/21% O2) were used to analyze the influence of the chemical structure, storage temperature and crystalline phase on the gas barrier behavior. The kinetic of the permeation process was investigated at different temperatures, ranging from 5 °C to 40 °C. Annealing thermal treatment on the samples led to the crystalline percentage, influencing especially the gas solubility process. Thermal properties such as Tg and χc, and mechanical properties such as tensile strength and modulus were remarkably improved with surface PLA modification. A more pronounced reinforcing effect was noted in the case of metallization, as well as improved gas barrier performance. Tensile testing and tensile cycling tests confirmed the rigidity of the films, with about a 20% loss of elasticity after 25 cycles loading. PMID:28773210

Barriers to Receiving Long-acting Reversible Contraception in the Postpartum Period.

PubMed

Zerden, Matthew L; Tang, Jennifer H; Stuart, Gretchen S; Norton, Deborah R; Verbiest, Sarah B; Brody, Seth

2015-01-01

To assess why postpartum women who desired long-acting reversible contraception (LARC) did not receive it in the postpartum period and to assess which contraceptive methods they were using instead. This was a subgroup analysis of 324 women enrolled in a randomized, controlled trial to receive or not receive an educational LARC script during their postpartum hospitalization. Participants in this subgroup analysis stated that they were either using LARC (n = 114) or interested in using LARC (n = 210) during a follow-up survey completed after their scheduled 6-week postpartum visit. Modified Poisson regression analysis was used to assess for characteristics associated with using LARC by the time of the follow-up survey. Women who were interested in LARC but not using it were more likely to be multiparous (relative risk [RR], 1.59; 95% CI, 1.19-2.11) and to have missed their postpartum visit (RR, 25.88; 95% CI, 3.75-178.44) compared with those using LARC. Among the interested 210 who were not using LARC, the most common reasons provided for non-use were that they were told to come back for another insertion visit (45%), missed the postpartum visit (26%), and could not afford LARC (11%). The most common contraceptive methods used instead of LARC were barrier methods (42%) and abstinence (19%); 18% used no contraceptive method. Two-thirds (65%) of postpartum women who desired to use LARC did not receive it in the postpartum period and used less effective contraceptive methods. Increasing access to immediate postpartum LARC and eliminating two-visit protocols for LARC insertion may increase postpartum LARC use. As the Affordable Care Act moves toward full implementation, it is necessary to understand the barriers that prevent interested patients from receiving LARC. Copyright © 2015 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Patient-perceived barriers to lifestyle interventions in cirrhosis.

PubMed

Ney, Michael; Gramlich, Leah; Mathiesen, Vanessa; Bailey, Robert J; Haykowsky, Mark; Ma, Mang; Abraldes, Juan G; Tandon, Puneeta

2017-01-01

Sarcopenia, muscle weakness, and physical frailty are independent predictors of mortality in cirrhosis. These adverse prognostic factors are potentially modifiable with lifestyle interventions, including adequate nutritional intake and physical activity. Our aim was to identify patient-perceived barriers and enablers to these interventions. Adult patients with cirrhosis were prospectively recruited from two tertiary care liver clinics. Patients were excluded if they had hepatocellular carcinoma beyond transplant criteria, other active malignancy, or advanced chronic disease. A total of 127 patients (mean age: 60 ± 9 years, 58% males, and 48% with Child-Pugh-B/C (CP-B/C) disease) were included. Two-thirds of the patients had cirrhosis related to alcohol or hepatitis C. CP-B/C patients were more likely to take oral nutritional supplements (56% vs 29%) and less likely to consume animal protein daily (66% vs 85%) when compared to CP-A patients. Early satiety, altered taste, and difficulty in buying/preparing meals were more common in CP-B/C patients and even present in 20-30% of CP-A patients. Most patients reported adequate funds to purchase food. As quantified by the International Physical Activity Questionnaire-Short Form, 47% reported low activity levels, with no significant differences between groups. CP-B/C patients were more fatigued with exercise, however, overall Exercise Benefits/Barriers Scale scores were similar across groups. Barriers to nutritional intake and physical activity are common in cirrhosis and should be evaluated and treated in all patients. Asking simple screening questions in clinic and referring at-risk patients to expert multidisciplinary providers is a reasonable strategy to address these barriers. Future research should evaluate techniques to overcome modifiable barriers and enhance enablers.

Patient training in cancer pain management using integrated print and video materials: a multisite randomized controlled trial.

PubMed

Syrjala, Karen L; Abrams, Janet R; Polissar, Nayak L; Hansberry, Jennifer; Robison, Jeanne; DuPen, Stuart; Stillman, Mark; Fredrickson, Marvin; Rivkin, Saul; Feldman, Eric; Gralow, Julie; Rieke, John W; Raish, Robert J; Lee, Douglas J; Cleeland, Charles S; DuPen, Anna

2008-03-01

Standard guidelines for cancer pain treatment routinely recommend training patients to reduce barriers to pain relief, use medications appropriately, and communicate their pain-related needs. Methods are needed to reduce professional time required while achieving sustained intervention effectiveness. In a multisite, randomized controlled trial, this study tested a pain training method versus a nutrition control. At six oncology clinics, physicians (N=22) and nurses (N=23) enrolled patients (N=93) who were over 18 years of age, with cancer diagnoses, pain, and a life expectancy of at least 6 months. Pain training and control interventions were matched for materials and method. Patients watched a video followed by about 20 min of manual-standardized training with an oncology nurse focused on reviewing the printed material and adapted to individual concerns of patients. A follow-up phone call after 72 h addressed individualized treatment content and pain communication. Assessments at baseline, one, three, and 6 months included barriers, the Brief Pain Inventory, opioid use, and physician and nurse ratings of their patients' pain. Trained versus control patients reported reduced barriers to pain relief (P<.001), lower usual pain (P=.03), and greater opioid use (P<.001). No pain training patients reported severe pain (>6 on a 0-10 scale) at 1-month outcomes (P=.03). Physician and nurse ratings were closer to patients' ratings of pain for trained versus nutrition groups (P=.04 and <.001, respectively). Training efficacy was not modified by patient characteristics. Using video and print materials, with brief individualized training, effectively improved pain management over time for cancer patients of varying diagnostic and demographic groups.

Force-momentum-based self-guided Langevin dynamics: A rapid sampling method that approaches the canonical ensemble

NASA Astrophysics Data System (ADS)

Wu, Xiongwu; Brooks, Bernard R.

2011-11-01

The self-guided Langevin dynamics (SGLD) is a method to accelerate conformational searching. This method is unique in the way that it selectively enhances and suppresses molecular motions based on their frequency to accelerate conformational searching without modifying energy surfaces or raising temperatures. It has been applied to studies of many long time scale events, such as protein folding. Recent progress in the understanding of the conformational distribution in SGLD simulations makes SGLD also an accurate method for quantitative studies. The SGLD partition function provides a way to convert the SGLD conformational distribution to the canonical ensemble distribution and to calculate ensemble average properties through reweighting. Based on the SGLD partition function, this work presents a force-momentum-based self-guided Langevin dynamics (SGLDfp) simulation method to directly sample the canonical ensemble. This method includes interaction forces in its guiding force to compensate the perturbation caused by the momentum-based guiding force so that it can approximately sample the canonical ensemble. Using several example systems, we demonstrate that SGLDfp simulations can approximately maintain the canonical ensemble distribution and significantly accelerate conformational searching. With optimal parameters, SGLDfp and SGLD simulations can cross energy barriers of more than 15 kT and 20 kT, respectively, at similar rates for LD simulations to cross energy barriers of 10 kT. The SGLDfp method is size extensive and works well for large systems. For studies where preserving accessible conformational space is critical, such as free energy calculations and protein folding studies, SGLDfp is an efficient approach to search and sample the conformational space.

Is the metaphor of 'barriers to change' useful in understanding implementation? Evidence from general medical practice.

PubMed

Checkland, Kath; Harrison, Stephen; Marshall, Martin

2007-04-01

To investigate how general medical practices in the UK react to bureaucratic initiatives, such as National Health Service (NHS) National Service Frameworks (NSFs), and to explore the value of the metaphor of 'barriers to change' for understanding this. Interviews, non-participant observation and documentary analysis within case studies of four practices in northern England. The practices had not actively implemented NSFs. At interview, various 'barriers' that had prevented implementation were listed, including the complexity of the documents and lack of time. Observation suggested that these barriers were constructions used by the participants to make sense of the situation in which they found themselves. The metaphor of 'removing barriers to change' was of limited use in a context where non-implementation of policy was an emergent property of underlying organizational realities, likely to be modifiable only if these realities were addressed.

Race Attribution Modifies the Association Between Daily Discrimination and Major Depressive Disorder Among Blacks: the Role of Gender and Ethnicity.

PubMed

Assari, Shervin; Watkins, Daphne C; Caldwell, Cleopatra H

2015-06-01

Although the association between discrimination and depression among Blacks is well-known, we do not know if this effect is influenced by race attribution. In this current study, we investigated the effect modification of race attribution on the association between everyday discrimination and major depressive disorder (MDD) among Blacks in the United States, and whether this effect modification is influenced by the intersection of ethnicity and gender. With a cross-sectional design, this study used data from the National Survey of American Life (NSAL), 2001-2003. The study included a nationally representative sample of Blacks (n = 5,008), composed of 3,570 African Americans and 1,438 Caribbean Blacks. Everyday discrimination, two single-item measures of race attribution (race as the major barrier against upward social mobility, and race as the main cause for being discriminated against) and 12-month MDD were measured. In the first step, we fit logistic regressions to the pooled sample. In the next step, we ran regressions specific to the intersections of ethnicity and gender. Interaction between race attribution and discrimination were also entered into the models. Among Caribbean Black men, the belief that race is a major barrier against one's own upward social mobility modified the association between exposure to daily discrimination and MDD. In this group, the association between discrimination and MDD was weaker among those who believed that race is a major barrier against one's own upward social mobility. Race attribution did not modify the association between discrimination and MDD among African American men, African American women, and Caribbean Black women. The other measure of race attribution (race as the main cause of being discriminated against) did not modify the association between discrimination and MDD in any ethnicity by gender subgroups. Among Caribbean Black men, the link between everyday discrimination and depression may depend on seeing race as the main barrier against upward social mobility. Among African American men and women, however, the link between discrimination and MDD does not depend on race attribution. Our results suggest that ethnicity, gender, and race attribution may alter the association between discrimination and risk of MDD among Blacks.

Overcoming psychosocial and developmental barriers to blood and marrow transplantation (BMT) in an adolescent/young adult (AYA) transgender patient with chronic myelogenous leukemia.

PubMed

Khazal, Sajad; Abdel-Azim, Hisham; Kapoor, Neena; Mahadeo, Kris M

2014-11-01

Adolescents/young adults (AYAs) afflicted with cancer face unique barriers to potentially standard curative therapies, such as blood and marrow transplantation (BMT). Transgender AYAs face additional barriers and there is a dearth of published literature regarding their oncology-related experience. We present the case of an AYA male-to-female (MTF) transgender patient on cross-sex hormone therapy, with a history of Chronic Myelogenous Leukemia (CML) and significant psychosocial barriers, which initially served as a barrier to BMT at two different centers; we modified our standard consent and education process and was able to successfully proceed with BMT and subsequently cure her CML. Despite unique challenges, AYA and transgender patients with significant psychosocial barriers may achieve successful outcomes with BMT. Research is needed regarding guidelines for cross-sex hormone therapy administration for patients undergoing BMT and other issues, which may be unique to the transgender experience.

Barrier inhomogeneities and electronic transport of Pt contacts to relatively highly doped n-type 4H-SiC

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

Huang, Lingqin, E-mail: lqhuang@jsnu.edu.cn, E-mail: dwang121@dlut.edu.cn; Wang, Dejun, E-mail: lqhuang@jsnu.edu.cn, E-mail: dwang121@dlut.edu.cn

The barrier characteristics of Pt contacts to relatively highly doped (∼1 × 10{sup 18 }cm{sup −3}) 4H-SiC were investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements in the temperature range of 160–573 K. The barrier height and ideally factor estimated from the I-V characteristics based on the thermionic emission model are abnormally temperature-dependent, which can be explained by assuming the presence of a double Gaussian distribution (GD) of inhomogeneous barrier heights. However, in the low temperature region (160–323 K), the obtained mean barrier height according to GD is lower than the actual mean value from C-V measurement. The values of barrier height determined from themore » thermionic field emission model are well consistent with those from the C-V measurements, which suggest that the current transport process could be modified by electron tunneling at low temperatures.« less

Barriers to advancement in academic surgery: views of senior residents and early career faculty.

PubMed

Cochran, Amalia; Elder, William B; Crandall, Marie; Brasel, Karen; Hauschild, Tricia; Neumayer, Leigh

2013-11-01

A significant faculty attrition rate exists in academic surgery. The authors hypothesized that senior residents and early-career faculty members have different perceptions of advancement barriers in academic surgery. A modified version of the Career Barriers Inventory-Revised was administered electronically to surgical residents and early-career surgical faculty members at 8 academic medical centers. Residents identified a lack of mentorship as a career barrier about half as often as faculty members. Residents were twice as likely as faculty members to view childbearing as a career barrier. Many early-career faculty members cite a lack of mentors as a limitation to their career development in academic surgery. Childbearing remains a complex perceived influence for female faculty members in particular. Female faculty members commonly perceive differential treatment and barriers on the basis of their sex. Faculty development programs should address both systemic and sex-specific obstacles if academic surgery is to remain a vibrant field. Copyright © 2013 Elsevier Inc. All rights reserved.

Surface morphological, electrical and transport properties of rapidly annealed double layers Ru/Cr Schottky structure on n-type InP

NASA Astrophysics Data System (ADS)

Shanthi Latha, K.; Rajagopal Reddy, V.

2017-07-01

The electrical and transport properties of a fabricated bilayer Ru/Cr/ n-InP Schottky diode (SD) have been investigated at different annealing temperatures. Atomic force microscopy results have showed that the overall surface morphology of the Ru/Cr/ n-InP SD is fairly smooth at elevated temperatures. High barrier height is achieved for the diode annealed at 300 °C compared to the as-deposited, annealed at 200 and 400 °C diodes. The series resistance and shunt resistance of the Ru/Cr/ n-InP SD are estimated by current-voltage method at different annealing temperatures. The barrier heights and series resistance are also determined by Cheung's and modified Norde functions. The interface state density of the Ru/Cr/ n-InP SD is found to be decreased after annealing at 300 °C and then slightly increased upon annealing at 400 °C. The difference between barrier heights obtained from current-voltage and capacitance-voltage is also discussed. Experimental results have showed that the Poole-Frenkel emission is found to be dominant in the lower bias region whereas Schottky emission is dominant in the higher bias region for the Ru/Cr/ n-InP SDs irrespective of annealing temperatures.

A formative evaluation of customized pamphlets to promote physical activity and symptom self-management in women with multiple sclerosis

PubMed Central

Plow, Matthew; Bethoux, Francois; Mai, Kimloan; Marcus, Bess

2014-01-01

Inactivity is a prevalent problem in the population affected with multiple sclerosis (MS). Thus, there is a need to develop and test physical activity (PA) interventions that can be widely disseminated. We conducted a formative evaluation as part of a randomized controlled trial of a pamphlet-based PA intervention among 30 women with MS. Pamphlets were customized to sub-sets of participants who shared similar symptoms and barriers to PA. Mixed methods were used to examine the intervention’s influence on self-efficacy, social support, processes of change and stages of change placement, as well as explore participants’ perceived barriers, motivators and strategies for engaging in a PA program. Results indicated that the intervention group significantly improved stages of change placement (F = 16.64, P < 0.01) and social support (F = 4.08, P = 0.05) in comparison to the control group. Fatigue, pain and lack of time were the commonly cited barriers to engage in the PA program; whereas the pamphlets, phone calls and action planning were cited as motivators. Participants used fatigue management strategies, enlisted social support and modified their environment to routinely engage in the PA program. Strategies were identified to improve the PA intervention in future research. PMID:24989822

Enhanced photochemical catalysis of TiO2 inverse opals by modification with ZnO or Fe2O3 using ALD and the hydrothermal method

NASA Astrophysics Data System (ADS)

Liu, Jiatong; Sun, Cuifeng; Fu, Ming; Long, Jie; He, Dawei; Wang, Yongsheng

2018-02-01

The development of porous materials exhibiting photon regulation abilities for improved photoelectrochemical catalysis performance is always one of the important goals of solar energy harvesting. In this study, methods to improve the photocatalytic activity of TiO2 inverse opals were discussed. TiO2 inverse opals were prepared by atomic layer deposition (ALD) using colloidal crystal templates. In addition, TiO2 inverse opal heterostructures were fabricated using colloidal heterocrystals by repeated vertical deposition using different colloidal spheres. The hydrothermal method and ALD were used to prepare ZnO- or Fe2O3-modified TiO2 inverse opals on the internal surfaces of the TiO2 porous structures. Although the photonic reflection band was not significantly varied by oxide modification, the presence of Fe2O3 in the TiO2 inverse opals enhanced their visible absorption. The conformally modified oxides on the TiO2 inverse opals could also form energy barriers and avoid the recombination of electrons and holes. The fabrication of the TiO2 photonic crystal heterostructures and modification with ZnO or Fe2O3 can enhance the photocatalytic activity of TiO2 inverse opals.

The intestinal barrier in multiple sclerosis: implications for pathophysiology and therapeutics.

PubMed

Camara-Lemarroy, Carlos R; Metz, Luanne; Meddings, Jonathan B; Sharkey, Keith A; Wee Yong, V

2018-05-30

Biological barriers are essential for the maintenance of homeostasis in health and disease. Breakdown of the intestinal barrier is an essential aspect of the pathophysiology of gastrointestinal inflammatory diseases, such as inflammatory bowel disease. A wealth of recent studies has shown that the intestinal microbiome, part of the brain-gut axis, could play a role in the pathophysiology of multiple sclerosis. However, an essential component of this axis, the intestinal barrier, has received much less attention. In this review, we describe the intestinal barrier as the physical and functional zone of interaction between the luminal microbiome and the host. Besides its essential role in the regulation of homeostatic processes, the intestinal barrier contains the gut mucosal immune system, a guardian of the integrity of the intestinal tract and the whole organism. Gastrointestinal disorders with intestinal barrier breakdown show evidence of CNS demyelination, and content of the intestinal microbiome entering into the circulation can impact the functions of CNS microglia. We highlight currently available studies suggesting that there is intestinal barrier dysfunction in multiple sclerosis. Finally, we address the mechanisms by which commonly used disease-modifying drugs in multiple sclerosis could alter the intestinal barrier and the microbiome, and we discuss the potential of barrier-stabilizing strategies, including probiotics and stabilization of tight junctions, as novel therapeutic avenues in multiple sclerosis.

Total quality management: Strengths and barriers to implementation and cultural adaptation

NASA Technical Reports Server (NTRS)

Siegfeldt, Denise V.; Glenn, Michael; Hamilton, Louise

1992-01-01

NASA/Langley Research Center (LaRC) is in the process of implementing Total Quality Management (TQM) throughout the organization in order to improve productivity and make the Center an even better place to work. The purpose of this project was to determine strengths and barriers to TQM being implemented and becoming a part of the organizational culture of the Human Resources Management Division (HRMD) at Langley. The target population for this project was both supervisory and nonsupervisory staff of the HMRD. In order to generate data on strengths and barriers to TQM implementation and cultural adaptation, a modified nominal group technique was used.

Improving particle beam acceleration in plasmas

NASA Astrophysics Data System (ADS)

C. de Sousa, M.; L. Caldas, I.

2018-04-01

The dynamics of wave-particle interactions in magnetized plasmas restricts the wave amplitude to moderate values for particle beam acceleration from rest energy. We analyze how a perturbing invariant robust barrier modifies the phase space of the system and enlarges the wave amplitude interval for particle acceleration. For low values of the wave amplitude, the acceleration becomes effective for particles with initial energy close to the rest energy. For higher values of the wave amplitude, the robust barrier controls chaos in the system and restores the acceleration process. We also determine the best position for the perturbing barrier in phase space in order to increase the final energy of the particles.

Effect of inhomogeneous Schottky barrier height of SnO2 nanowires device

NASA Astrophysics Data System (ADS)

Amorim, Cleber A.; Bernardo, Eric P.; Leite, Edson R.; Chiquito, Adenilson J.

2018-05-01

The current–voltage (I–V) characteristics of metal–semiconductor junction (Au–Ni/SnO2/Au–Ni) Schottky barrier in SnO2 nanowires were investigated over a wide temperature range. By using the Schottky–Mott model, the zero bias barrier height Φ B was estimated from I–V characteristics, and it was found to increase with increasing temperature; on the other hand the ideality factor (n) was found to decrease with increasing temperature. The variation in the Schottky barrier and n was attributed to the spatial inhomogeneity of the Schottky barrier height. The experimental I–V characteristics exhibited a Gaussian distribution having mean barrier heights {\\overline{{{Φ }}}}B of 0.30 eV and standard deviation σ s of 60 meV. Additionally, the Richardson modified constant was obtained to be 70 A cm‑2 K‑2, leading to an effective mass of 0.58m 0. Consequently, the temperature dependence of I–V characteristics of the SnO2 nanowire devices can be successfully explained on the Schottky–Mott theory framework taking into account a Gaussian distribution of barrier heights.

Motivators and barriers to a healthy postpartum lifestyle in women at increased cardiovascular and metabolic risk: a focus-group study.

PubMed

Hoedjes, Meeke; Berks, Durk; Vogel, Ineke; Franx, Arie; Duvekot, Johannes J; Oenema, Anke; Steegers, Eric A P; Raat, Hein

2012-01-01

To describe the motivators and barriers to the adoption of a healthy postpartum lifestyle after a pregnancy complicated by preeclampsia, intrauterine growth restriction, and/or gestational diabetes. Thirty-six women with complicated pregnancies participated in six focus-group interviews that aimed to explore the perceptions of modifiable determinants of postpartum lifestyle. Although women expressed that they intended to live a healthy postpartum lifestyle, it was generally not achieved. The motivators included improving their own current health condition as well as modeling a healthy lifestyle for their children. Important barriers were reported to be lack of knowledge, poor recovery, and lack of professional support after delivery. The reported motivators and barriers can be used to develop a postpartum lifestyle intervention.

Advanced Environmental Barrier Coatings Development for Si-Based Ceramics

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Choi, R. Sung; Robinson, Raymond C.; Lee, Kang N.; Bhatt, Ramakrishna T.; Miller, Robert A.

2005-01-01

Advanced environmental barrier coating concepts based on multi-component HfO2 (ZrO2) and modified mullite systems are developed for monolithic Si3N4 and SiC/SiC ceramic matrix composite (CMC) applications. Comprehensive testing approaches were established using the water vapor cyclic furnace, high pressure burner rig and laser heat flux steam rig to evaluate the coating water vapor stability, cyclic durability, radiation and erosion resistance under simulated engine environments. Test results demonstrated the feasibility and durability of the environmental barrier coating systems for 2700 to 3000 F monolithic Si3N4 and SiC/SiC CMC component applications. The high-temperature-capable environmental barrier coating systems are being further developed and optimized in collaboration with engine companies for advanced turbine engine applications.

Spectroscopic investigation of a dielectric barrier discharge in modified atmosphere packaging

NASA Astrophysics Data System (ADS)

Milosavljević, Vladimir; Cullen, Patrick J.

2017-11-01

Diagnostics of a dielectric barrier discharge (DBD), in a sealed package (with and without meat) filled with gas mixtures of oxygen and carbon-dioxide (O2-CO2), is reported. The generation and evaluation of the plasma chemistry induced within the confines of the sealed package is studied. The plasma discharges were analyzed by optical emission spectroscopy (OES) and optical absorption spectroscopy (OAS) over a range of plasma process parameters. The study includes a detailed experimental investigation of the spatial and temporal spectroscopic data and links them with plasma kinetics. The results from the spectral radiation from package provide information about the electron energy distribution function. The experimental data indicates that the humidity level in the package with and without meat is unchanged, and that the gas temperature was not significantly modified. Oxygen and nitrogen radicals (trapped gas atmosphere and modified atmosphere) are increased in the package containing meat; at the same time there is no evidence of the presence of carbon monoxide molecules. The role of the nitrogen molecule in the quenching of O2 and CO2 molecules is also evaluated.

Triode carbon nanotube field emission display using barrier rib structure and manufacturing method thereof

DOEpatents

Han, In-taek; Kim, Jong-min

2003-01-01

A triode carbon nanotube field emission display (FED) using a barrier rib structure and a manufacturing method thereof are provided. In a triode carbon nanotube FED employing barrier ribs, barrier ribs are formed on cathode lines by a screen printing method, a mesh structure is mounted on the barrier ribs, and a spacer is inserted between the barrier ribs through slots of the mesh structure, thereby stably fixing the mesh structure and the spacer within a FED panel due to support by the barrier ribs.

Barriers and facilitators for consumer adherence to the dietary guidelines for Americans: the HEALTH study.

PubMed

Nicklas, Theresa A; Jahns, Lisa; Bogle, Margaret L; Chester, Deirdra N; Giovanni, Maria; Klurfeld, David M; Laugero, Kevin; Liu, Yan; Lopez, Sandra; Tucker, Katherine L

2013-10-01

The majority of the US population does not meet recommendations for consumption of milk, whole grains, fruit, and vegetables. The goal of our study was to understand barriers and facilitators to adherence to the Dietary Guidelines for Americans for four nutrient-rich food groups in fifth-grade children and unrelated adult caregivers across six sites in a multistate study. A total of 281 unrelated adult caregivers (32% African American, 33% European American, and 35% Hispanic American) and 321 children (33% African American, 33% European American, and 34% Hispanic American) participated in 97 Nominal Group Technique sessions. Nominal Group Technique is a qualitative method of data collection that enables a group to generate and prioritize a large number of issues within a structure that gives everyone an equal voice. The core barriers specific to unrelated adult caregivers were lack of meal preparation skills or recipes (whole grains, fruit, vegetables); difficulty in changing eating habits (whole grains, fruit, vegetables), cost (milk, whole grains, fruit, vegetables), lack of knowledge of recommendation/portion/health benefits (milk, vegetables), and taste (milk, whole grains, vegetables). Specific to children, the core barriers were competing foods (ie, soda, junk foods, sugary foods [whole grains, milk, fruit, vegetables]), health concerns (ie, milk allergy/upset stomach [milk]), taste/flavor/smell (milk, whole grains, fruit, vegetables), forget to eat them (vegetables, fruit), and hard to consume or figure out the recommended amount (milk, fruit). For both unrelated adult caregivers and children, reported facilitators closely coincided with the barriers, highlighting modifiable conditions that could help individuals to meet the Dietary Guidelines for Americans. Copyright © 2013 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Tracking the Effect of Adatom Electronegativity on Systematically Modified AlGaN/GaN Schottky Interfaces.

PubMed

Reiner, Maria; Pietschnig, Rudolf; Ostermaier, Clemens

2015-10-21

The influence of surface modifications on the Schottky barrier height for gallium nitride semiconductor devices is frequently underestimated or neglected in investigations thereof. We show that a strong dependency of Schottky barrier heights for nickel/aluminum-gallium nitride (0001) contacts on the surface terminations exists: a linear correlation of increasing barrier height with increasing electronegativity of superficial adatoms is observed. The negatively charged adatoms compete with the present nitrogen over the available gallium (or aluminum) orbital to form an electrically improved surface termination. The resulting modification of the surface dipoles and hence polarization of the surface termination causes observed band bending. Our findings suggest that the greatest Schottky barrier heights are achieved by increasing the concentration of the most polarized fluorine-gallium (-aluminum) bonds at the surface. An increase in barrier height from 0.7 to 1.1 eV after a 15% fluorine termination is obtained with ideality factors of 1.10 ± 0.05. The presence of surface dipoles that are changing the surface energy is proven by the sessile drop method as the electronegativity difference and polarization influences the contact angle. The extracted decrease in the Lifshitz-van-der-Waals component from 48.8 to 40.4 mJ/m(2) with increasing electronegativity and concentration of surface adatoms confirms the presence of increasing surface dipoles: as the polarizability of equally charged anions decreases with increasing electronegativity, the diiodomethane contact angles increase significantly from 14° up to 39° after the 15% fluorine termination. Therefore, a linear correlation between increasing anion electronegativity of the (Al)GaN termination and total surface energy within a 95% confidence interval is obtained. Furthermore, our results reveal a generally strong Lewis basicity of (Al)GaN surfaces explaining the high chemical inertness of the surfaces.

[Adhesion prevention after Cesarean section by short-term biological barrier of modified chitosan].

PubMed

Shen, Wei; Shen, Guofang; Li, Lüwei

2014-02-25

To evaluate the efficacies of modified chitosan, an adhesive prevention substance, as a biological barrier for preventing adhesion after Cesarean section. A total of 250 cases undergoing primary Cesarean section from January 2011 to June 2012 at our hospital were recruited. They were randomly divided into experiment (n = 130) and control (n = 120) groups. The experiment group received modified chitosan during Cesarean section while no adhesive prevention substance was offered for the control group. Postoperative flatus time, postoperative infection and pelvic adhesion were used to evaluate the clinical efficacies. For the experiment group, the average postoperative flatus time was (25 ± 7) hours. Three cases had postoperative infections with a postoperative infection rate of 2.3%. There were 2 cases of pelvic adhesion (pelvic adhesion rate: 1.5%) during the postoperative follow-up period. For the control group, the average postoperative flatus time was (34 ± 11) hours. Five cases had postoperative infections with a postoperative infection rate of 4.2%. There were 5 cases of pelvic adhesion (pelvic adhesion rate: 4.2%) during the postoperative follow-up period. There were significant inter-group differences in postoperative flatus time, postoperative infection and pelvic adhesion (P < 0.05). Modified chitosan can prevent pelvic adhesion after Cesarean section.

Infection control procedures used in conjunction with computed dental radiography.

PubMed

Hubar, J S; Gardiner, D M

2000-10-01

Infection control guidelines for dental radiography have been modified since 1986, when the American Dental Association and the Centers for Disease Control and Prevention supported the concept of "universal blood and body fluid precautions." With the introduction of computed digital radiography, hardware manufacturers recommend that alternative infection control techniques are necessary to prevent potential damage to the digital x-ray sensors placed inside the patient's mouth. Thirty first-year dental hygiene students were asked to insert and remove a Schick CDR number 2 size intraoral digital x-ray sensor into modified Rinn XCP bitewing bite blocks and a modified Rinn Snap-a-ray five times with each of the recommended infection control covers. Reduced rates of cross contamination are possible if the plastic barrier envelope has an additional latex finger cot stretched over it and the x-ray sensor. Sole usage of a latex finger cot will result in a reduced incidence of contamination, but still not to acceptable levels. However, a plastic barrier envelope placed over the x-ray sensor and over the modified XCP bite block together or a covered sensor in a Snap-a-ray under normal conditions does not result in a perforation and is least likely to result in cross contamination.

A Lagrange multiplier and Hopfield-type barrier function method for the traveling salesman problem.

PubMed

Dang, Chuangyin; Xu, Lei

2002-02-01

A Lagrange multiplier and Hopfield-type barrier function method is proposed for approximating a solution of the traveling salesman problem. The method is derived from applications of Lagrange multipliers and a Hopfield-type barrier function and attempts to produce a solution of high quality by generating a minimum point of a barrier problem for a sequence of descending values of the barrier parameter. For any given value of the barrier parameter, the method searches for a minimum point of the barrier problem in a feasible descent direction, which has a desired property that lower and upper bounds on variables are always satisfied automatically if the step length is a number between zero and one. At each iteration, the feasible descent direction is found by updating Lagrange multipliers with a globally convergent iterative procedure. For any given value of the barrier parameter, the method converges to a stationary point of the barrier problem without any condition on the objective function. Theoretical and numerical results show that the method seems more effective and efficient than the softassign algorithm.

Transferrin-modified liposome promotes α-mangostin to penetrate the blood-brain barrier.

PubMed

Chen, Zhi-Lan; Huang, Man; Wang, Xia-Rong; Fu, Jun; Han, Min; Shen, You-Qing; Xia, Zheng; Gao, Jian-Qing

2016-02-01

α-Mangostin (α-M) is a polyphenolic xanthone that protects and improves the survival of cerebral cortical neurons against Aβ oligomer-induced toxicity in rats. α-M is a potential candidate as a treatment for Alzheimer's disease (AD). However, the efficacy was limited by the poor penetration of the drug through the blood-brain barrier (BBB). In this study, we modified the α-M liposome with transferrin (Tf) and investigated the intracellular distribution of liposomes in bEnd3 cells. In addition, the transport of α-M across the BBB in the Tf(α-M) liposome group was examined. In vitro studies demonstrated that the Tf(α-M) liposome could cross the BBB in the form of an integrated liposome. Results of the in vivo studies on the α-M distribution in the brain demonstrated that the Tf(α-M) liposome improved the brain delivery of α-M. These results indicated that the Tf liposome is a potential carrier of α-M against AD. The use of α-Mangostin (α-M) as a potential agent to treat Alzheimer's disease (AD) has been reported. However, its use is limited by the poor penetration through the blood brain barrier. The delivery of this agent by transferrin-modified liposomes was investigated by the authors in this study. The positive results could point to a better drug delivery system for brain targeting. Copyright © 2015 Elsevier Inc. All rights reserved.

Tailoring Lipid and Polymeric Nanoparticles as siRNA Carriers towards the Blood-Brain Barrier - from Targeting to Safe Administration.

PubMed

Gomes, Maria João; Fernandes, Carlos; Martins, Susana; Borges, Fernanda; Sarmento, Bruno

2017-03-01

Blood-brain barrier is a tightly packed layer of endothelial cells surrounding the brain that acts as the main obstacle for drugs enter the central nervous system (CNS), due to its unique features, as tight junctions and drug efflux systems. Therefore, since the incidence of CNS disorders is increasing worldwide, medical therapeutics need to be improved. Consequently, aiming to surpass blood-brain barrier and overcome CNS disabilities, silencing P-glycoprotein as a drug efflux transporter at brain endothelial cells through siRNA is considered a promising approach. For siRNA enzymatic protection and efficient delivery to its target, two different nanoparticles platforms, solid lipid (SLN) and poly-lactic-co-glycolic (PLGA) nanoparticles were used in this study. Polymeric PLGA nanoparticles were around 115 nm in size and had 50 % of siRNA association efficiency, while SLN presented 150 nm and association efficiency close to 52 %. Their surface was functionalized with a peptide-binding transferrin receptor, in a site-oriented manner confirmed by NMR, and their targeting ability against human brain endothelial cells was successfully demonstrated by fluorescence microscopy and flow cytometry. The interaction of modified nanoparticles with brain endothelial cells increased 3-fold compared to non-modified lipid nanoparticles, and 4-fold compared to non-modified PLGA nanoparticles, respectively. These nanosystems, which were also demonstrated to be safe for human brain endothelial cells, without significant cytotoxicity, bring a new hopeful breath to the future of brain diseases therapies.

Inclusive Competitive Game Play Through Balanced Sensory Feedback.

PubMed

Westin, Thomas; Söderström, David; Karlsson, Olov; Peiris, Ranil

2017-01-01

While game accessibility has improved significantly the last few years, there are still barriers for equal participation and multiplayer issues have been less researched. Game balance is here about making the game fair in a player versus player competitive game. One difficult design task is to balance the game to be fair regardless of visual or hearing capabilities, with clearly different requirements. This paper explores a tentative design method for enabling inclusive competitive game-play without individual adaptations of game rules that could spoil the game. The method involved applying a unified design method to design an unbalanced game, then modifying visual feedback as a hypothetical balanced design, and testing the game with totally 52 people with and without visual or hearing disabilities in three workshops. Game balance was evaluated based on score differences and less structured qualitative data, and a redesign of the game was made. Conclusions are a tentative method for balancing a multiplayer, competitive game without changing game rules and how the method can be applied.

Achieving Crossed Strong Barrier Coverage in Wireless Sensor Network.

PubMed

Han, Ruisong; Yang, Wei; Zhang, Li

2018-02-10

Barrier coverage has been widely used to detect intrusions in wireless sensor networks (WSNs). It can fulfill the monitoring task while extending the lifetime of the network. Though barrier coverage in WSNs has been intensively studied in recent years, previous research failed to consider the problem of intrusion in transversal directions. If an intruder knows the deployment configuration of sensor nodes, then there is a high probability that it may traverse the whole target region from particular directions, without being detected. In this paper, we introduce the concept of crossed barrier coverage that can overcome this defect. We prove that the problem of finding the maximum number of crossed barriers is NP-hard and integer linear programming (ILP) is used to formulate the optimization problem. The branch-and-bound algorithm is adopted to determine the maximum number of crossed barriers. In addition, we also propose a multi-round shortest path algorithm (MSPA) to solve the optimization problem, which works heuristically to guarantee efficiency while maintaining near-optimal solutions. Several conventional algorithms for finding the maximum number of disjoint strong barriers are also modified to solve the crossed barrier problem and for the purpose of comparison. Extensive simulation studies demonstrate the effectiveness of MSPA.

Understanding and meeting injection device needs in multiple sclerosis: a survey of patient attitudes and practices

PubMed Central

Verdun di Cantogno, Elisabetta; Russell, Susan; Snow, Tom

2011-01-01

Background: All established disease-modifying drugs for multiple sclerosis require parenteral administration, which can cause difficulties for some patients, sometimes leading to suboptimal adherence. A new electronic autoinjection device has been designed to address these issues. Methods: Patients with relapsing multiple sclerosis currently receiving subcutaneous or intramuscular interferon beta-1a, interferon beta-1b, or glatiramer acetate completed an online questionnaire (July 4–25, 2008) that surveyed current injection practices, experiences with current injection methods, and impressions and appeal of the new device. Results: In total, 422 patients completed the survey, of whom 44% used autoinjectors, 43% prefilled syringes, and 13% syringes and vials; overall, 66% currently self-injected. Physical and psychological barriers to self-injection included difficulty with injections, needle phobia, and concerns over correct injection technique. Only 40% of respondents were “very satisfied” with their current injection method. The new electronic autoinjector was rated as “very appealing” by 65% of patients. The benefits of the new device included the ability to customize injection settings and to review dosing history. Conclusion: New technologies may help patients overcome physical and psychological barriers to self-injection. The combination of a reliable and flexible autoinjection device with dose-monitoring technology may improve communication between health care professionals and patients, and improve treatment adherence. PMID:21573048

Comparison of atmospheric microplasma and plasma jet irradiation for increasing of skin permeability

NASA Astrophysics Data System (ADS)

Shimizu, K.; Tran, N. A.; Hayashida, K.; Blajan, M.

2016-08-01

Atmospheric plasma is attracting interest for medical applications such as sterilization, treatment of cancer cells and blood coagulation. Application of atmospheric plasma in dermatology has potential as a novel tool for wound healing, skin rejuvenation and treatment of wrinkles. In this study, we investigated the enhancement of percutaneous absorption of dye as alternative agents of transdermal drugs. Hypodermic needles are often the only way to deliver large-molecule drugs into the dermis, although a safe transdermal drug delivery method that does not require needles would be desirable. We therefore explored the feasibility of using atmospheric microplasma irradiation to enhance percutaneous absorption of drugs, as an alternative delivery method to conventional hypodermic needles. Pig skin was used as a biological sample, exposed to atmospheric microplasma, and analyzed by attenuated total reflection-Fourier transform infrared spectroscopy. A tape stripping test, a representative method for evaluating skin barrier performance, was also conducted for comparison. Transepidermal water loss (TEWL) was measured and compared with and without atmospheric microplasma irradiation, to quantify water evaporation from the inner body through the skin barrier. The results show that the stratum corneum, the outermost skin layer, could be chemically and physically modified by atmospheric microplasma irradiation. Physical damage to the skin by microplasma irradiation and an atmospheric plasma jet was also assessed by observing the skin surface. The results suggest that atmospheric microplasma has the potential to enhance percutaneous absorption.

Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

NASA Astrophysics Data System (ADS)

Qu, Guangzhou; Liang, Dongli; Qu, Dong; Huang, Yimei; Li, Jie

2014-06-01

In this study, two regeneration methods (dielectric barrier discharge (DBD) plasma and ozone (O3) regeneration) of saturated granular activated carbon (GAC) with pentachlorophenol (PCP) were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with O3 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3 regeneration. O3 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cycles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after O3 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that O3 regeneration has a lower weight loss than DBD plasma regeneration.

Review of potential subsurface permeable barrier emplacement and monitoring technologies

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

Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.

1994-02-01

This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, ormore » excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods.« less

Blood-brain barrier structure and function and the challenges for CNS drug delivery.

PubMed

Abbott, N Joan

2013-05-01

The neurons of the central nervous system (CNS) require precise control of their bathing microenvironment for optimal function, and an important element in this control is the blood-brain barrier (BBB). The BBB is formed by the endothelial cells lining the brain microvessels, under the inductive influence of neighbouring cell types within the 'neurovascular unit' (NVU) including astrocytes and pericytes. The endothelium forms the major interface between the blood and the CNS, and by a combination of low passive permeability and presence of specific transport systems, enzymes and receptors regulates molecular and cellular traffic across the barrier layer. A number of methods and models are available for examining BBB permeation in vivo and in vitro, and can give valuable information on the mechanisms by which therapeutic agents and constructs permeate, ways to optimize permeation, and implications for drug discovery, delivery and toxicity. For treating lysosomal storage diseases (LSDs), models can be included that mimic aspects of the disease, including genetically-modified animals, and in vitro models can be used to examine the effects of cells of the NVU on the BBB under pathological conditions. For testing CNS drug delivery, several in vitro models now provide reliable prediction of penetration of drugs including large molecules and artificial constructs with promising potential in treating LSDs. For many of these diseases it is still not clear how best to deliver appropriate drugs to the CNS, and a concerted approach using a variety of models and methods can give critical insights and indicate practical solutions.

A choline derivate-modified nanoprobe for glioma diagnosis using MRI

NASA Astrophysics Data System (ADS)

Li, Jianfeng; Huang, Shixian; Shao, Kun; Liu, Yang; An, Sai; Kuang, Yuyang; Guo, Yubo; Ma, Haojun; Wang, Xuxia; Jiang, Chen

2013-04-01

Gadolinium (Gd) chelate contrast-enhanced magnetic resonance imaging (MRI) is a preferred method of glioma detection and preoperative localisation because it offers high spatial resolution and non-invasive deep tissue penetration. Gd-based contrast agents, such as Gd-diethyltriaminepentaacetic acid (DTPA-Gd, Magnevist), are widely used clinically for tumor diagnosis. However, the Gd-based MRI approach is limited for patients with glioma who have an uncompromised blood-brain barrier (BBB). Moreover, the rapid renal clearance and non-specificity of such contrast agents further hinders their prevalence. We present a choline derivate (CD)-modified nanoprobe with BBB permeability, glioma specificity and a long blood half-life. Specific accumulation of the nanoprobe in gliomas and subsequent MRI contrast enhancement are demonstrated in vitro in U87 MG cells and in vivo in a xenograft nude model. BBB and glioma dual targeting by this nanoprobe may facilitate precise detection of gliomas with an uncompromised BBB and may offer better preoperative and intraoperative tumor localization.

Solution of monotone complementarity and general convex programming problems using a modified potential reduction interior point method

DOE PAGES

Huang, Kuo -Ling; Mehrotra, Sanjay

2016-11-08

We present a homogeneous algorithm equipped with a modified potential function for the monotone complementarity problem. We show that this potential function is reduced by at least a constant amount if a scaled Lipschitz condition (SLC) is satisfied. A practical algorithm based on this potential function is implemented in a software package named iOptimize. The implementation in iOptimize maintains global linear and polynomial time convergence properties, while achieving practical performance. It either successfully solves the problem, or concludes that the SLC is not satisfied. When compared with the mature software package MOSEK (barrier solver version 6.0.0.106), iOptimize solves convex quadraticmore » programming problems, convex quadratically constrained quadratic programming problems, and general convex programming problems in fewer iterations. Moreover, several problems for which MOSEK fails are solved to optimality. In addition, we also find that iOptimize detects infeasibility more reliably than the general nonlinear solvers Ipopt (version 3.9.2) and Knitro (version 8.0).« less

Materials characterization with MeV ions

NASA Astrophysics Data System (ADS)

Conlon, T. W.

1989-04-01

The inherent atomic and nuclear properties of energetic ions in materials can be exploited to characterize as well as to modify materials' properties. In nuclear reactors keV ions from neutron collisions damage containment materials. However, basic studies of the interactions of such ions has yielded improved understanding of their properties and has even led to a tailoring of conditions so that the ions can be made to beneficially modify structures (by ion implantation). At higher energies an understanding of the ion-material interaction provides techniques such as PIXE, RBS, and ERD for nondestructive analysis, either in broad beam or "microbeam" mode. At high energies still penetration of the Coulomb barrier opens up activation methods for materials' characterization (CPAA, NRA, TLA etc.). A short discussion of the general properties of energetic ions in materials is followed by a brief introduction to our generic work in these areas, and some examples of current work in the areas of: activation for the radioisotope labelling of nonmetals, mass resolved ERDA using TOF techniques and submicron MeV microprobes.

Legislative history of recent primary safety belt laws

DOT National Transportation Integrated Search

1999-01-01

This document summarizes the strategies that supported or opposed new legislative provisions and the barriers encountered in modifying safety belt laws prior to December 1997. This study developed legislative analyses of six jurisdictions that upgrad...

Adhesive flexible barrier film, method of forming same, and organic electronic device including same

DOEpatents

Blizzard, John Donald; Weidner, William Kenneth

2013-02-05

An adhesive flexible barrier film comprises a substrate and a barrier layer disposed on the substrate. The barrier layer is formed from a barrier composition comprising an organosilicon compound. The adhesive flexible barrier film also comprises an adhesive layer disposed on the barrier layer and formed from an adhesive composition. A method of forming the adhesive flexible barrier film comprises the steps of disposing the barrier composition on the substrate to form the barrier layer, disposing the adhesive composition on the barrier layer to form the adhesive layer, and curing the barrier layer and the adhesive layer. The adhesive flexible barrier film may be utilized in organic electronic devices.

A mechanism study of sound wave-trapping barriers.

PubMed

Yang, Cheng; Pan, Jie; Cheng, Li

2013-09-01

The performance of a sound barrier is usually degraded if a large reflecting surface is placed on the source side. A wave-trapping barrier (WTB), with its inner surface covered by wedge-shaped structures, has been proposed to confine waves within the area between the barrier and the reflecting surface, and thus improve the performance. In this paper, the deterioration in performance of a conventional sound barrier due to the reflecting surface is first explained in terms of the resonance effect of the trapped modes. At each resonance frequency, a strong and mode-controlled sound field is generated by the noise source both within and in the vicinity outside the region bounded by the sound barrier and the reflecting surface. It is found that the peak sound pressures in the barrier's shadow zone, which correspond to the minimum values in the barrier's insertion loss, are largely determined by the resonance frequencies and by the shapes and losses of the trapped modes. These peak pressures usually result in high sound intensity component impinging normal to the barrier surface near the top. The WTB can alter the sound wave diffraction at the top of the barrier if the wavelengths of the sound wave are comparable or smaller than the dimensions of the wedge. In this case, the modified barrier profile is capable of re-organizing the pressure distribution within the bounded domain and altering the acoustic properties near the top of the sound barrier.

Studies of the Electrohydrodynamic Force Produced in a Dielectric Barrier Discharge for Flow Control. Report no. 2, Phase 3

DTIC Science & Technology

2010-02-01

applied between the electrodes at a repetition rate of a few kHz (for spanwise as well as streamwise configurations of the DBD actuators with respect to...the electronic version) 1. Introduction Surface dielectric barrier discharges ( DBDs ) at atmospheric pressure can generate a flow or modify the...to the momentum transfer from charged particles to neutral molecules in a gas discharge. In recent papers [7–9], we presented studies of surface DBDs

Susceptibility constants of airborne bacteria to dielectric barrier discharge for antibacterial performance evaluation.

PubMed

Park, Chul Woo; Hwang, Jungho

2013-01-15

Dielectric barrier discharge (DBD) is a promising method to remove contaminant bioaerosols. The collection efficiency of a DBD reactor is an important factor for determining a reactor's removal efficiency. Without considering collection, simply defining the inactivation efficiency based on colony counting numbers for DBD as on and off may lead to overestimation of the inactivation efficiency of the DBD reactor. One-pass removal tests of bioaerosols were carried out to deduce the inactivation efficiency of the DBD reactor using both aerosol- and colony-counting methods. Our DBD reactor showed good performance for removing test bioaerosols for an applied voltage of 7.5 kV and a residence time of 0.24s, with η(CFU), η(Number), and η(Inactivation) values of 94%, 64%, and 83%, respectively. Additionally, we introduce the susceptibility constant of bioaerosols to DBD as a quantitative parameter for the performance evaluation of a DBD reactor. The modified susceptibility constant, which is the ratio of the susceptibility constant to the volume of the plasma reactor, has been successfully demonstrated for the performance evaluation of different sized DBD reactors under different DBD operating conditions. Our methodology will be used for design optimization, performance evaluation, and prediction of power consumption of DBD for industrial applications. Copyright © 2012 Elsevier B.V. All rights reserved.

A modified 3D algorithm for road traffic noise attenuation calculations in large urban areas.

PubMed

Wang, Haibo; Cai, Ming; Yao, Yifan

2017-07-01

The primary objective of this study is the development and application of a 3D road traffic noise attenuation calculation algorithm. First, the traditional empirical method does not address problems caused by non-direct occlusion by buildings and the different building heights. In contrast, this study considers the volume ratio of the buildings and the area ratio of the projection of buildings adjacent to the road. The influence of the ground affection is analyzed. The insertion loss due to barriers (infinite length and finite barriers) is also synthesized in the algorithm. Second, the impact of different road segmentation is analyzed. Through the case of Pearl River New Town, it is recommended that 5° is the most appropriate scanning angle as the computational time is acceptable and the average error is approximately 3.1 dB. In addition, the algorithm requires only 1/17 of the time that the beam tracking method requires at the cost of more imprecise calculation results. Finally, the noise calculation for a large urban area with a high density of buildings shows the feasibility of the 3D noise attenuation calculation algorithm. The algorithm is expected to be applied in projects requiring large area noise simulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Accelerated molecular dynamics: A promising and efficient simulation method for biomolecules

NASA Astrophysics Data System (ADS)

Hamelberg, Donald; Mongan, John; McCammon, J. Andrew

2004-06-01

Many interesting dynamic properties of biological molecules cannot be simulated directly using molecular dynamics because of nanosecond time scale limitations. These systems are trapped in potential energy minima with high free energy barriers for large numbers of computational steps. The dynamic evolution of many molecular systems occurs through a series of rare events as the system moves from one potential energy basin to another. Therefore, we have proposed a robust bias potential function that can be used in an efficient accelerated molecular dynamics approach to simulate the transition of high energy barriers without any advance knowledge of the location of either the potential energy wells or saddle points. In this method, the potential energy landscape is altered by adding a bias potential to the true potential such that the escape rates from potential wells are enhanced, which accelerates and extends the time scale in molecular dynamics simulations. Our definition of the bias potential echoes the underlying shape of the potential energy landscape on the modified surface, thus allowing for the potential energy minima to be well defined, and hence properly sampled during the simulation. We have shown that our approach, which can be extended to biomolecules, samples the conformational space more efficiently than normal molecular dynamics simulations, and converges to the correct canonical distribution.

Formative research to develop a lifestyle application (app) for African American breast cancer survivors

PubMed Central

Smith, Selina A.; Whitehead, Mary S.; Sheats, Joyce Q.; Fontenot, Brittney; Alema-Mensah, Ernest; Ansa, Benjamin

2016-01-01

Background There is a proliferation of lifestyle-oriented mobile technologies; however, few have targeted users. Through intervention mapping, investigators and community partners completed Steps 1–3 (needs assessment, formulation of change objectives, and selection of theory-based methods) of a process to develop a mobile cancer prevention application (app) for cancer prevention. The aim of this qualitative study was to complete Step 4 (intervention development) by eliciting input from African American (AA) breast cancer survivors (BCSs) to guide app development. Methods Four focus group discussions (n=60) and three individual semi-structured interviews (n=36) were conducted with AA BCSs (40–72 years of age) to assess barriers and strategies for lifestyle change. All focus groups and interviews were recorded and transcribed verbatim. Data were analyzed with NVivo qualitative data analysis software version 10, allowing categories, themes, and patterns to emerge. Results Three categories and related themes emerged from the analysis: 1) perceptions about modifiable risk factors; 2) strategies related to adherence to cancer prevention guidelines; and 3) app components to address barriers to adherence. Participant perceptions, strategies, and recommended components guided development of the app. Conclusions For development of a mobile cancer prevention app, these findings will assist investigators in targeting features that are usable, acceptable, and accessible for AA BCSs. PMID:27583307

Understanding safety culture in long-term care: a case study.

PubMed

Halligan, Michelle H; Zecevic, Aleksandra; Kothari, Anita R; Salmoni, Alan W; Orchard, Treena

2014-12-01

This case study aimed to understand safety culture in a high-risk secured unit for cognitively impaired residents in a long-term care (LTC) facility. Specific objectives included the following: diagnosing the present level of safety culture maturity using the Patient Safety Culture Improvement Tool (PSCIT), examining the barriers to a positive safety culture, and identifying actions for improvement. A mixed methods design was used within a secured unit for cognitively impaired residents in a Canadian nonprofit LTC facility. Semistructured interviews, a focus group, and the Modified Stanford Patient Safety Culture Survey Instrument were used to explore this topic. Data were synthesized to situate safety maturity of the unit within the PSCIT adapted for LTC. Results indicated a reactive culture, where safety systems were piecemeal and developed only in response to adverse events and/or regulatory requirements. A punitive regulatory environment, inadequate resources, heavy workloads, poor interdisciplinary collaboration, and resident safety training capacity were major barriers to improving safety. This study highlights the importance of understanding a unit's safety culture and identifies the PSCIT as a useful framework for planning future improvements to safety culture maturity. Incorporating mixed methods in the study of health care safety culture provided a good model that can be recommended for future use in research and LTC practice.

Human serum albumin nanoparticles modified with apolipoprotein A-I cross the blood-brain barrier and enter the rodent brain.

PubMed

Zensi, Anja; Begley, David; Pontikis, Charles; Legros, Celine; Mihoreanu, Larisa; Büchel, Claudia; Kreuter, Jörg

2010-12-01

Nanoparticles made of human serum albumin (HSA) and modified with apolipoproteins have previously been shown to transport drugs, which normally do not enter the brain, across the blood-brain barrier (BBB). However the precise mechanism by which nanoparticles with different apolipoproteins on their surface can target to the brain, as yet, has not been totally elucidated. In the present study, HSA nanoparticles with covalently bound apolipoprotein A-I (Apo A-I) as a targetor for brain capillary endothelial cells were injected intravenously into SV 129 mice and Wistar rats. The rodents were sacrificed after 15 or 30 min, and their brains were examined by transmission electron microscopy. Apo A-I nanoparticles could be found inside the endothelial cells of brain capillaries as well as within parenchymal brain tissue of both, mice and rats, whereas control particles without Apo A-I on their surface did not cross the BBB during our experiments. The maintenance of tight junction integrity and barrier function during treatment with nanoparticles was demonstrated by perfusion with a fixative containing lanthanum nitrate as an electron dense marker for the permeability of tight junctions.

College Institutional Characteristics and the Use of Barrier Methods among Undergraduate Students

ERIC Educational Resources Information Center

Griner, Stacey B.; Thompson, Erika L.; Vamos, Cheryl A.; Logan, Rachel; Vázquez-Otero, Coralia; Daley, Ellen M.

2017-01-01

Sexually transmitted infections (STIs) may be prevented through the use of barrier methods, but rates of use among US college students are low. Previous research focuses on individual-level factors influencing barrier method use, but few studies consider community-level influences. This study examined consistency of barrier use by college…

Stakeholders identify similar barriers but different strategies to facilitate return-to-work: A vignette of a worker with an upper extremity condition.

PubMed

Peters, Susan E; Truong, Anthony P; Johnston, Venerina

2018-01-01

Stakeholders involved in the return-to-work (RTW) process have different roles and qualificationsOBJECTIVE:To explore the perspectives of Australian stakeholders of the RTW barriers and strategies for a worker with an upper extremity condition and a complex workers' compensation case. Using a case vignette, stakeholders were asked to identify barriers and recommend strategies to facilitate RTW. Content analysis was performed on the open-ended responses. The responses were categorised into RTW barriers and strategies using the biopsychosocial model. Pearson's Chi Square and ANOVA were performed to establish group differences. 621 participants (488 healthcare providers (HCPs), 62 employers, 55 insurers and 16 lawyers) identified 36 barriers (31 modifiable): 4 demographic; 8 biological; 15 psychological and 9 social barriers. 484 participants reported 16 RTW strategies: 4 biological; 6 psychological and 6 social strategies. 'Work relationship stressors' (83.4%) and 'Personal relationship stressors' (64.7%) were the most frequently nominated barriers. HCPs most frequently nominated 'Pain management' (49.6%), while employers, insurers and lawyers nominated 'RTW planning/Suitable duties programs' (40.5%; 42.9%; 80%). Stakeholders perceived similar barriers for RTW but recommended different strategies. Stakeholders appeared to be more proficient in identifying barriers than recommending strategies. Future research should focus on tools to both identify RTW barriers and direct intervention.

Thorough exploration of complex environments with a space-based potential field

NASA Astrophysics Data System (ADS)

Kenealy, Alina; Primiano, Nicholas; Keyes, Alex; Lyons, Damian M.

2015-01-01

Robotic exploration, for the purposes of search and rescue or explosive device detection, can be improved by using a team of multiple robots. Potential field navigation methods offer natural and efficient distributed exploration algorithms in which team members are mutually repelled to spread out and cover the area efficiently. However, they also suffer from field minima issues. Liu and Lyons proposed a Space-Based Potential Field (SBPF) algorithm that disperses robots efficiently and also ensures they are driven in a distributed fashion to cover complex geometry. In this paper, the approach is modified to handle two problems with the original SBPF method: fast exploration of enclosed spaces, and fast navigation of convex obstacles. Firstly, a "gate-sensing" function was implemented. The function draws the robot to narrow openings, such as doors or corridors that it might otherwise pass by, to ensure every room can be explored. Secondly, an improved obstacle field conveyor belt function was developed which allows the robot to avoid walls and barriers while using their surface as a motion guide to avoid being trapped. Simulation results, where the modified SPBF program controls the MobileSim Pioneer 3-AT simulator program, are presented for a selection of maps that capture difficult to explore geometries. Physical robot results are also presented, where a team of Pioneer 3-AT robots is controlled by the modified SBPF program. Data collected prior to the improvements, new simulation results, and robot experiments are presented as evidence of performance improvements.

Alloyed coatings for dispersion strengthened alloys

NASA Technical Reports Server (NTRS)

Wermuth, F. R.; Stetson, A. R.

1971-01-01

Processing techniques were developed for applying several diffusion barriers to TD-Ni and TD-NiCr. Barrier coated specimens of both substrates were clad with Ni-Cr-Al and Fe-Cr-Al alloys and diffusion annealed in argon. Measurement of the aluminum distribution after annealing showed that, of the readily applicable diffusion barriers, a slurry applied tungsten barrier most effectively inhibited the diffusion of aluminum from the Ni-Cr-Al clad into the TD-alloy substrates. No barrier effectively limited interdiffusion of the Fe-Cr-Al clad with the substrates. A duplex process was then developed for applying Ni-Cr-Al coating compositions to the tungsten barrier coated substrates. A Ni-(16 to 32)Cr-3Si modifier was applied by slurry spraying and firing in vacuum, and was then aluminized by a fusion slurry process. Cyclic oxidation tests at 2300 F resulted in early coating failure due to inadequate edge coverage and areas of coating porosity. EMP analysis showed that oxidation had consumed 70 to 80 percent of the aluminum in the coating in less than 50 hours.

Listeriolysin S: A bacteriocin from epidemic Listeria monocytogenes strains that targets the gut microbiota.

PubMed

Quereda, Juan J; Meza-Torres, Jazmín; Cossart, Pascale; Pizarro-Cerdá, Javier

2017-07-04

Listeria monocytogenes is a Gram-positive food-borne pathogen that in humans may traverse the intestinal, placental and blood/brain barriers, causing gastroenteritis, abortions and meningitis. Crossing of these barriers is dependent on the bacterial ability to enter host cells, and several L. monocytogenes surface and secreted virulence factors are known to facilitate entry and the intracellular lifecycle. The study of L. monocytogenes strains associated to human listeriosis epidemics has revealed the presence of novel virulence factors. One such factor is Listeriolysin S, a thiazole/oxazole modified microcin that displays bactericidal activity and modifies the host microbiota during infection. Our recent results therefore highlight the interaction of L. monocytogenes with gut microbes as a crucial step in epidemic listeriosis. In this article, we will discuss novel implications for this family of toxins in the pathogenesis of diverse medically relevant microorganisms.

Listeriolysin S: A bacteriocin from epidemic Listeria monocytogenes strains that targets the gut microbiota

PubMed Central

Quereda, Juan J.; Meza-Torres, Jazmín; Cossart, Pascale; Pizarro-Cerdá, Javier

2017-01-01

ABSTRACT Listeria monocytogenes is a Gram-positive food-borne pathogen that in humans may traverse the intestinal, placental and blood/brain barriers, causing gastroenteritis, abortions and meningitis. Crossing of these barriers is dependent on the bacterial ability to enter host cells, and several L. monocytogenes surface and secreted virulence factors are known to facilitate entry and the intracellular lifecycle. The study of L. monocytogenes strains associated to human listeriosis epidemics has revealed the presence of novel virulence factors. One such factor is Listeriolysin S, a thiazole/oxazole modified microcin that displays bactericidal activity and modifies the host microbiota during infection. Our recent results therefore highlight the interaction of L. monocytogenes with gut microbes as a crucial step in epidemic listeriosis. In this article, we will discuss novel implications for this family of toxins in the pathogenesis of diverse medically relevant microorganisms. PMID:28156183

Silicon oxide permeation barrier coating of PET bottles and foils

NASA Astrophysics Data System (ADS)

Steves, Simon; Deilmann, Michael; Awakowicz, Peter

2009-10-01

Modern packaging materials such as polyethylene terephthalate (PET) have displaced established materials in many areas of food and beverage packaging. Plastic packing materials offer are various advantages concerning production and handling. PET bottles for instance are non-breakable and lightweight compared to glass and metal containers. However, PET offers poor barrier properties against gas permeation. Therefore, the shelf live of packaged food is reduced. Permeation of gases can be reduced by depositing transparent plasma polymerized silicon oxide (SiOx) barrier coatings. A microwave (2.45 GHz) driven low pressure plasma reactor is developed based on a modified Plasmaline antenna to treat PET foils or bottles. To increase the barrier properties of the coatings furthermore a RF substrate bias (13.56 MHz) is applied. The composition of the coatings is analyzed by means of Fourier transform infrared (FTIR) spectroscopy regarding carbon and hydrogen content. Influence of gas phase composition and substrate bias on chemical composition of the coatings is discussed. A strong relation between barrier properties and film composition is found: good oxygen barriers are observed as carbon content is reduced and films become quartz-like. Regarding oxygen permeation a barrier improvement factor (BIF) of 70 is achieved.

Fitting of the Thomson scattering density and temperature profiles on the COMPASS tokamak

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

Stefanikova, E.; Division of Fusion Plasma Physics, KTH Royal Institute of Technology, SE-10691 Stockholm; Peterka, M.

2016-11-15

A new technique for fitting the full radial profiles of electron density and temperature obtained by the Thomson scattering diagnostic in H-mode discharges on the COMPASS tokamak is described. The technique combines the conventionally used modified hyperbolic tangent function for the edge transport barrier (pedestal) fitting and a modification of a Gaussian function for fitting the core plasma. Low number of parameters of this combined function and their straightforward interpretability and controllability provide a robust method for obtaining physically reasonable profile fits. Deconvolution with the diagnostic instrument function is applied on the profile fit, taking into account the dependence onmore » the actual magnetic configuration.« less

Oncologists' strategies and barriers to effective communication about the end of life.

PubMed

Granek, Leeat; Krzyzanowska, Monika K; Tozer, Richard; Mazzotta, Paolo

2013-07-01

Communicating about the end of life with patients has been reported as one of the most difficult and stressful part of the work of oncologists. Despite this fact, oncologists receive little training in this area, and many do not communicate effectively with patients. The purpose of this analysis, part of a larger study examining oncologists' experiences of patient loss, was to explore oncologists' communication strategies and communication barriers when discussing end-of-life issues with patients. Twenty oncologists were interviewed at three hospitals about their communication strategies on end-of-life issues with patients. The data were analyzed using the grounded theory method. The findings revealed the strategies to effective communication about the end of life included: being open and honest; having ongoing, early conversations; communicating about modifying treatment goals; and balancing hope and reality. Barriers to implementing these strategies fell broadly into three domains, including physician factors, patient factors, and institutional factors. Physician factors included difficulty with treatment and palliation, personal discomfort with death and dying, diffusion of responsibility among colleagues, using the "death-defying mode," lack of experience, and lack of mentorship. Patient factors included, patients and/or families being reluctant to talk about the end of life, language barriers, and younger age. Institutional factors included stigma around palliative care, lack of protocol about end-of-life issues; and lack of training for oncologists on how to talk with patients about end-of-life issues. We conclude by drawing implications from our study and suggest that further research and intervention are necessary to aid oncologists in achieving effective communication about end-of-life issues.

Misperceptions regarding protective barrier method use for safer sex among African-American women who have sex with women.

PubMed

Muzny, Christina A; Harbison, Hanne S; Pembleton, Elizabeth S; Hook, Edward W; Austin, Erika L

2013-05-01

Barrier methods for HIV and sexually transmissible infection (STI) prevention among women who have sex with women (WSW) are available, although their effectiveness has not been systematically investigated. These methods are infrequently used by WSW. As part of a larger study on STI risk perceptions and safer sex among African-American WSW, we discovered several misperceptions regarding barrier methods that may be associated with their limited use. Participants were recruited from the Jefferson County Health Department STI Clinic and through word of mouth in Birmingham, Alabama, for focus group discussions exploring perceptions of STI risk and safer sex. Seven focus groups with 29 participants were conducted (age range: 19-43 years). Several misperceptions regarding barrier methods were identified, notably the conflation of dental dams and female condoms. Descriptions of the use of barrier methods were qualified with phrases suggesting their hypothetical, rather than actual, use. Additional evidence that barrier methods are not actually used came from beliefs that dental dams and female condoms are available in major grocery stores or department store chains. Those providing sexual health services to WSW should be cautious in assuming that WSW have accurate information regarding barrier methods for safer sex. Sexual health services provided to WSW should include an accurate description of what barrier methods are, how to distinguish them from barrier methods more commonly used during heterosexual sex (female and male condoms), and how to use them correctly. Future studies are needed to address how effectively these measures reduce transmission of STIs among WSW.

Investigation of p-type depletion doping for InGaN/GaN-based light-emitting diodes

NASA Astrophysics Data System (ADS)

Zhang, Yiping; Zhang, Zi-Hui; Tan, Swee Tiam; Hernandez-Martinez, Pedro Ludwig; Zhu, Binbin; Lu, Shunpeng; Kang, Xue Jun; Sun, Xiao Wei; Demir, Hilmi Volkan

2017-01-01

Due to the limitation of the hole injection, p-type doping is essential to improve the performance of InGaN/GaN multiple quantum well light-emitting diodes (LEDs). In this work, we propose and show a depletion-region Mg-doping method. Here we systematically analyze the effectiveness of different Mg-doping profiles ranging from the electron blocking layer to the active region. Numerical computations show that the Mg-doping decreases the valence band barrier for holes and thus enhances the hole transportation. The proposed depletion-region Mg-doping approach also increases the barrier height for electrons, which leads to a reduced electron overflow, while increasing the hole concentration in the p-GaN layer. Experimentally measured external quantum efficiency indicates that Mg-doping position is vitally important. The doping in or adjacent to the quantum well degrades the LED performance due to Mg diffusion, increasing the corresponding nonradiative recombination, which is well supported by the measured carrier lifetimes. The experimental results are well numerically reproduced by modifying the nonradiative recombination lifetimes, which further validate the effectiveness of our approach.

Function of Platelet-Induced Epithelial Attachment at Titanium Surfaces Inhibits Microbial Colonization.

PubMed

Maeno, M; Lee, C; Kim, D M; Da Silva, J; Nagai, S; Sugawara, S; Nara, Y; Kihara, H; Nagai, M

2017-06-01

The aim of this study was to evaluate the barrier function of platelet-induced epithelial sheets on titanium surfaces. The lack of functional peri-implant epithelial sealing with basal lamina (BL) attachment at the interface of the implant and the adjacent epithelium allows for bacterial invasion, which may lead to peri-implantitis. Although various approaches have been reported to combat bacterial infection by surface modifications to titanium, none of these have been successful in a clinical application. In our previous study, surface modification with protease-activated receptor 4-activating peptide (PAR4-AP), which induced platelet activation and aggregation, was successful in demonstrating epithelial attachment via BL and epithelial sheet formation on the titanium surface. We hypothesized that the platelet-induced epithelial sheet on PAR4-AP-modified titanium surfaces would reduce bacterial attachment, penetration, and invasion. Titanium surface was modified with PAR4-AP and incubated with platelet-rich plasma (PRP). The aggregated platelets released collagen IV, a critical BL component, onto the PAR4-AP-modified titanium surface. Then, human gingival epithelial cells were seeded on the modified titanium surface and formed epithelial sheets. Green fluorescent protein (GFP)-expressing Escherichia coli was cultured onto PAR4-AP-modified titanium with and without epithelial sheet formation. While Escherichia coli accumulated densely onto the PAR4-AP titanium lacking epithelial sheet, few Escherichia coli were observed on the epithelial sheet on the PAR4-AP surface. No bacterial invasion into the interface of the epithelial sheet and the titanium surface was observed. These in vitro results indicate the efficacy of a platelet-induced epithelial barrier that functions to prevent bacterial attachment, penetration, and invasion on PAR4-AP-modified titanium.

Systematic planning of disconnection to enhance conservation success in a modified world.

PubMed

Hermoso, Virgilio; Januchowski-Hartley, Stephanie R; Linke, Simon

2015-12-01

Maintaining spatial-temporal connectivity for conservation is necessary to allow the persistence of ecological processes and the biodiversity they sustain. However, conservation practice in human-modified environments can also benefit from prescribed disconnection through the implementation of barriers. Barriers, such as fences or dams, and buffer zones can be a cost-effective way of addressing threats caused by a globally connected world, such as the propagation of invasive species and diseases, creating refuge areas for native biodiversity and helping reduce economic losses caused by native wildlife or invasive species. Despite the global attention that disconnection has received, no clear framework exists to guide the allocation of barriers for conservation management. Here we propose that the implementation of barriers for conservation should be systematically planned, considering ecological trade-offs for multiple species (easing threats vs. interruption of ecosystem processes) and socio-economic cost-benefits (implementation cost vs. reduced human-wildlife conflicts), rather than using ad-hoc opportunistic criteria or accommodating conservation needs for individual species. Such a systematic approach is necessary to ensure both socially acceptable and ecologically effective use of disconnections as a conservation tool and ideally planned across different realms so co-benefits or trade-offs can be accounted for. However, any implementation of disconnection for conservation should be cautiously considered if uncertainty in effectiveness of the barrier and ecological impacts to other species are high. We also suggest the need for improved approaches to monitoring to learn from previous successes and failures. Our recommendations should guide the systematic evaluation and allocation of barriers to help enhance the value of this conservation tool in the face of increasing propagation of threats worldwide. However, new tools and collaborative frameworks across different realms are needed to help stakeholders make better informed decision. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of perfluorodecyltrichlorosilane on the surface properties and anti-corrosion behavior of poly(dimethylsiloxane)-ZnO coatings

NASA Astrophysics Data System (ADS)

Arukalam, Innocent O.; Meng, Meijiang; Xiao, Haigang; Ma, Yuantai; Oguzie, Emeka E.; Li, Ying

2018-03-01

Poly(dimethylsiloxane)-ZnO coatings modified with different amounts of perfluorodecyltrichlorosilane (FDTS) were prepared using sol-gel technique. The results of field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) examinations showed that the surface structures and roughness of the coatings were respectively influenced by the increasing addition of FDTS. The water contact angle measurements showed maximum value of 130.52° with the 0.10 g FDTS-modified coating sample. The X-ray photoelectron spectroscopy (XPS) results indicated the coatings' hydrophobicity was also influenced by surface chemistry. The FTIR-ATR characterization results showed there was remarkable increase in the crystallinity of 0.10 g FDTS-modified coating after modification, and was confirmed by differential scanning calorimetry (DSC) analysis of crystallization temperature and the X-ray diffraction (XRD) results with an estimation of 71.29% percent crystallinity. The mechanical properties of the coatings were also conducted. The EIS measurements for anti-corrosion behavior showed that 0.10 g FDTS-modified coating had the highest barrier performance and lowest rate of degradation. Indeed, the obtained data have demonstrated that 0.10 g (≈ 0.18%) FDTS produced the most significantly effect on the surface and barrier properties of the coatings and thus, can effectively be used for anti-corrosion application in the marine environments.

Antibacterial Activity of a Novel Peptide-Modified Lysin Against Acinetobacter baumannii and Pseudomonas aeruginosa

PubMed Central

Yang, Hang; Wang, Mengyue; Yu, Junping; Wei, Hongping

2015-01-01

The global emergence of multidrug-resistant (MDR) bacteria is a growing threat to public health worldwide. Natural bacteriophage lysins are promising alternatives in the treatment of infections caused by Gram-positive pathogens, but not Gram-negative ones, like Acinetobacter baumannii and Pseudomonas aeruginosa, due to the barriers posed by their outer membranes. Recently, modifying a natural lysin with an antimicrobial peptide was found able to break the barriers, and to kill Gram-negative pathogens. Herein, a new peptide-modified lysin (PlyA) was constructed by fusing the cecropin A peptide residues 1–8 (KWKLFKKI) with the OBPgp279 lysin and its antibacterial activity was studied. PlyA showed good and broad antibacterial activities against logarithmic phase A. baumannii and P. aeruginosa, but much reduced activities against the cells in stationary phase. Addition of outer membrane permeabilizers (EDTA and citric acid) could enhance the antibacterial activity of PlyA against stationary phase cells. Finally, no antibacterial activity of PlyA could be observed in some bio-matrices, such as culture media, milk, and sera. In conclusion, we reported here a novel peptide-modified lysin with significant antibacterial activity against both logarithmic (without OMPs) and stationary phase (with OMPs) A. baumannii and P. aeruginosa cells in buffer, but further optimization is needed to achieve broad activity in diverse bio-matrices. PMID:26733995

Evaluation of the potential toxicity of unmodified and modified cyclodextrins on murine blood-brain barrier endothelial cells.

PubMed

Shityakov, Sergey; Salmas, Ramin Ekhteiari; Salvador, Ellaine; Roewer, Norbert; Broscheit, Jens; Förster, Carola

2016-04-01

In this study, we investigated the cytotoxic effects of unmodified α-cyclodextrin (α-CD) and modified cyclodextrins, including trimethyl-β-cyclodextrin (TRIMEB) and hydroxypropyl-β-cyclodextrin (HPβCD), on immortalized murine microvascular endothelial (cEND) cells of the blood-brain barrier (BBB). A CellTiter-Glo viability test, performed on the cEND cells showed significant differences among the different cyclodextrins. After 24 hr of incubation, TRIMEB was the most cytotoxic, and HPβCD was non-toxic. α-CD and TRIMEB exhibited greater cytotoxicity in the Dulbecco's modified Eagle's medium than in heat-inactivated human serum indicating protective properties of the human serum. The predicted dynamic toxicity profiles (Td) for α-CD and TRIMEB indicated higher cytotoxicity for these cyclodextrins compared to the reference compound (dimethylsulfoxide). Molecular dynamics simulation of cholesterol binding to the CDs suggested that not just cholesterol but phospholipids extraction might be involved in the cytotoxicity. Overall, the results demonstrate that HPβCD has the potential to be used as a candidate for drug delivery vector development and signify a correlation between the in vitro cytotoxic effect and cholesterol binding of cyclodextrins.

Minimum free-energy paths for the self-organization of polymer brushes.

PubMed

Gleria, Ignacio; Mocskos, Esteban; Tagliazucchi, Mario

2017-03-22

A methodology to calculate minimum free-energy paths based on the combination of a molecular theory and the improved string method is introduced and applied to study the self-organization of polymer brushes under poor solvent conditions. Polymer brushes in a poor solvent cannot undergo macroscopic phase separation due to the physical constraint imposed by the grafting points; therefore, they microphase separate forming aggregates. Under some conditions, the theory predicts that the homogeneous brush and the aggregates can exist as two different minima of the free energy. The theoretical methodology introduced in this work allows us to predict the minimum free-energy path connecting these two minima as well as the morphology of the system along the path. It is shown that the transition between the homogeneous brush and the aggregates may involve a free-energy barrier or be barrierless depending on the relative stability of the two morphologies and the chain length and grafting density of the polymer. In the case where a free-energy barrier exists, one of the morphologies is a metastable structure and, therefore, the properties of the brush as the quality of the solvent is cycled are expected to display hysteresis. The theory is also applied to study the adhesion/deadhesion transition between two opposing surfaces modified by identical polymer brushes and it is shown that this process may also require surpassing a free-energy barrier.

Flyweight 3D Graphene Scaffolds with Microinterface Barrier-Derived Tunable Thermal Insulation and Flame Retardancy.

PubMed

Zhang, Qiangqiang; Hao, Menglong; Xu, Xiang; Xiong, Guoping; Li, Hui; Fisher, Timothy S

2017-04-26

In this article, flyweight three-dimensional (3D) graphene scaffolds (GSs) have been demonstrated with a microinterface barrier-derived thermal insulation and flame retardancy characteristics. Such 3D GSs were fabricated by a modified hydrothermal method and a unidirectional freeze-casting process with hierarchical porous microstructures. Because of high porosity (99.9%), significant phonon scattering, and strong π-π interaction at the interface barriers of multilayer graphene cellular walls, the GSs demonstrate a sequence of multifunctional properties simultaneously, such as lightweight density, thermal insulating characteristics, and outstanding mechanical robustness. At 100 °C, oxidized GSs exhibit a thermal conductivity of 0.0126 ± 0.0010 W/(m K) in vacuum. The thermal conductivity of oxidized GSs remains relatively unaffected despite large-scale deformation-induced densification of the microstructures, as compared to the behavior of reduced GSs (rGSs) whose thermal conductivity increases dramatically under compression. The contrasting behavior of oxidized GSs and rGSs appears to derive from large differences in the intersheet contact resistance and varying intrinsic thermal conductivity between reduced and oxidized graphene sheets. The oxidized GSs also exhibit excellent flame retardant behavior and mechanical robustness, with only 2% strength decay after flame treatment. In a broader context, this work demonstrates a useful strategy to design porous nanomaterials with a tunable heat conduction behavior through interface engineering at the nanoscale.

A formative evaluation of customized pamphlets to promote physical activity and symptom self-management in women with multiple sclerosis.

PubMed

Plow, Matthew; Bethoux, Francois; Mai, Kimloan; Marcus, Bess

2014-10-01

Inactivity is a prevalent problem in the population affected with multiple sclerosis (MS). Thus, there is a need to develop and test physical activity (PA) interventions that can be widely disseminated. We conducted a formative evaluation as part of a randomized controlled trial of a pamphlet-based PA intervention among 30 women with MS. Pamphlets were customized to sub-sets of participants who shared similar symptoms and barriers to PA. Mixed methods were used to examine the intervention's influence on self-efficacy, social support, processes of change and stages of change placement, as well as explore participants' perceived barriers, motivators and strategies for engaging in a PA program. Results indicated that the intervention group significantly improved stages of change placement (F = 16.64, P < 0.01) and social support (F = 4.08, P = 0.05) in comparison to the control group. Fatigue, pain and lack of time were the commonly cited barriers to engage in the PA program; whereas the pamphlets, phone calls and action planning were cited as motivators. Participants used fatigue management strategies, enlisted social support and modified their environment to routinely engage in the PA program. Strategies were identified to improve the PA intervention in future research. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Metal diffusion barriers for GaAs solar cells.

PubMed

van Leest, R H; Mulder, P; Bauhuis, G J; Cheun, H; Lee, H; Yoon, W; van der Heijden, R; Bongers, E; Vlieg, E; Schermer, J J

2017-03-15

In this study accelerated ageing testing (AAT), J-V characterization and TEM imaging in combination with phase diagram data from literature are used to assess the potential of Ti, Ni, Pd and Pt as diffusion barriers for Au/Cu-based metallization of III-V solar cells. Ni barriers show the largest potential as at an AAT temperature of 250 °C both cells with 10 and 100 nm thick Ni barriers show significantly better performance compared to Au/Cu cells, with the cells with 10 nm Ni barriers even showing virtually no degradation after 7.5 days at 250 °C (equivalent to 10 years at 100 °C at an E a of 0.70 eV). Detailed investigation shows that Ni does not act as a barrier in the classical sense, i.e. preventing diffusion of Cu and Au across the barrier. Instead Ni modifies or slows down the interactions taking place during device degradation and thus effectively acts as an 'interaction' barrier. Different interactions occur at temperatures below and above 250 °C and for thin (10 nm) and thick (100 nm) barriers. The results of this study indicate that 10-100 nm thick Ni intermediate layers in the Cu/Au based metallization of III-V solar cells may be beneficial to improve the device stability upon exposure to elevated temperatures.

Barriers to Implementation of Optimal Laboratory Biosafety Practices in Pakistan

PubMed Central

Shafaq, Humaira; Hasan, Rumina; Qureshi, Shahida M.; Dojki, Maqboola; Hughes, Molly A.; Zaidi, Anita K. M.; Khan, Erum

2016-01-01

The primary goal of biosafety education is to ensure safe practices among workers in biomedical laboratories. Despite several educational workshops by the Pakistan Biological Safety Association (PBSA), compliance with safe practices among laboratory workers remains low. To determine barriers to implementation of recommended biosafety practices among biomedical laboratory workers in Pakistan, we conducted a questionnaire-based survey of participants attending 2 workshops focusing on biosafety practices in Karachi and Lahore in February 2015. Questionnaires were developed by modifying the BARRIERS scale in which respondents are required to rate barriers on a 1-4 scale. Nineteen of the original 29 barriers were included and subcategorized into 4 groups: awareness, material quality, presentation, and workplace barriers. Workshops were attended by 64 participants. Among barriers that were rated as moderate to great barriers by at least 50% of respondents were: lack of time to read biosafety guidelines (workplace subscale), lack of staff authorization to change/improve practice (workplace subscale), no career or self-improvement advantages to the staff for implementing optimal practices (workplace subscale), and unclear practice implications (presentation subscale). A lack of recognition for employees' rights and benefits in the workplace was found to be a predominant reason for a lack of compliance. Based on perceived barriers, substantial improvement in work environment, worker facilitation, and enabling are needed for achieving improved or optimal biosafety practices in Pakistan. PMID:27400192

Perceived Barriers to Smoking Cessation among Adults with Substance Use Disorders

PubMed Central

McHugh, R. Kathryn; Votaw, Victoria R.; Fulciniti, Francesca; Connery, Hilary S.; Griffin, Margaret L.; Monti, Peter M.; Weiss, Roger D.

2017-01-01

The majority of adults seeking substance use disorder treatment also smoke. Smoking is associated with greater substance use disorder severity, poorer treatment outcome, and increased mortality among those with substance use disorders. Yet, engaging this population in smoking cessation treatment is a significant challenge. The aim of this study was to examine perceived barriers to smoking cessation among treatment-seeking adults with alcohol or opioid use disorder. Additionally, we examined whether anxiety sensitivity--a known risk factor for barriers to smoking cessation in the general population--was associated with more barriers to smoking cessation in this sample. A sample of 208 adults was recruited for a one-time study and completed self-report measures of anxiety sensitivity and perceived barriers to smoking cessation. Results indicated that the most common barriers were anxiety (82% of the sample), tension/irritability (76%), and concerns about the ability to maintain sobriety from their primary substance of abuse (64%). Those who reported more barriers also reported lower confidence in the ability to change their smoking behavior. Higher anxiety sensitivity was associated with more perceived barriers to smoking cessation, even when controlling for nicotine dependence severity. These results suggest that there are several perceived barriers to smoking cessation among treatment-seeking adults with substance use disorders. In addition to psychoeducational interventions aimed to modify negative beliefs about smoking cessation, anxiety sensitivity may be a promising therapeutic target in this population. PMID:28132700

Barrier Methods of Birth Control: Spermicide, Condom, Sponge, Diaphragm, and Cervical Cap

MedlinePlus

... Education & Events Advocacy For Patients About ACOG Barrier Methods of Birth Control: Spermicide, Condom, Sponge, Diaphragm, and ... Cervical Cap FAQ022, March 2018 PDF Format Barrier Methods of Birth Control: Spermicide, Condom, Sponge, Diaphragm, and ...

Method of installing subsurface barrier

DOEpatents

Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

2007-10-09

Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

The effects of interfacial recombination and injection barrier on the electrical characteristics of perovskite solar cells

NASA Astrophysics Data System (ADS)

Shi, Lin Xing; Wang, Zi Shuai; Huang, Zengguang; Sha, Wei E. I.; Wang, Haoran; Zhou, Zhen

2018-02-01

Charge carrier recombination in the perovskite solar cells (PSCs) has a deep influence on the electrical performance, such as open circuit voltage, short circuit current, fill factor and ultimately power conversion efficiency. The impacts of injection barrier, recombination channels, doping properties of carrier transport layers and light intensity on the performance of PSCs are theoretically investigated by drift-diffusion model in this work. The results indicate that due to the injection barrier at the interfaces of perovskite and carrier transport layer, the accumulated carriers modify the electric field distribution throughout the PSCs. Thus, a zero electric field is generated at a specific applied voltage, with greatly increases the interfacial recombination, resulting in a local kink of current density-voltage (J-V) curve. This work provides an effective strategy to improve the efficiency of PSCs by pertinently reducing both the injection barrier and interfacial recombination.

Complementary Barrier Infrared Detector (CBIRD) with Double Tunnel Junction Contact and Quantum Dot Barrier Infrared Detector (QD-BIRD)

NASA Technical Reports Server (NTRS)

Ting, David Z.-Y; Soibel, Alexander; Khoshakhlagh, Arezou; Keo, Sam A.; Nguyen, Jean; Hoglund, Linda; Mumolo, Jason M.; Liu, John K.; Rafol, Sir B.; Hill, Cory J.;

Thick thermal barrier coatings for diesel components

NASA Technical Reports Server (NTRS)

Yonushonis, T. M.

1991-01-01

An engineered thick thermal barrier coating consisting of multiple layers of zirconia and CoCrAlY with a zirconia top layer and having a system thermal conductance less than 410 w/m(exp 2)K exceeded the 100 hour engine durability goals set forth in this program. The thermal barrier coatings were intact at the test conclusion. Back to back single cylinder research engine tests were conducted with watercooled, metal hardware and oil-cooled, thermal barrier coating insulated hardware to determine apparent heat release and fuel economy. Apparent heat release data revealed that the insulated engine had a shorter ignition delay and a longer combustion duration than the metal engine. The insulated engine fuel economy was approximately two percent worse on average for this series of tests. There was no attempt to optimize engine efficiency of the insulated engine by modifying the engine timing, coating, or other techniques.

Barriers and enablers to proper diabetic foot care amongst community dwellers in an Asian population: a qualitative study

PubMed Central

Cuttilan, Amit Nirmal; Pearce, Christopher J.

2017-01-01

Background Diabetic foot complications are common within Asian populations. They arise due to poor diabetic control and foot care. In this study, we aimed to identify the causes for proper and improper diabetic foot care. Methods A qualitative study consisting of key informant interviews with 17 healthcare professionals, including doctors and various allied health workers, was conducted. Participants included had at least five years of caring for diabetic foot patients either in public institutions or private clinics. Data collected was analyzed via thematic analysis. Results Diabetic patients were generally observed to have a mixture of proper and improper information and beliefs which eventually resulted in the extent of proper foot care. Factors which influenced the extent of proper and improper state of information and beliefs were classified into predisposing and precipitating factors. Predisposing factors were further categorised into modifiable factors (e.g., education level, socioeconomic status, social support) and non-modifiable factors (e.g., age, presence and severity of co-morbidities restricting ability to selfcare, past experiences). Precipitating factors were categorized into patient factors (e.g., degree of reception of information, presence of psychological barriers), provider factors (presence and degree of multi-disciplinary approach to care, presence of administrative inconveniences) and disease factors (presence of diabetic sensory neuropathy, complexity of disease process). Conclusions The extent of proper foot care amongst diabetic patients is influenced by numerous predisposing and precipitating factors. Further studies can look at further development of the described structure as well as quantitatively defining the various components and factors which make up the described system. PMID:28706922

A novel method for calculating the energy barriers for carbon diffusion in ferrite under heterogeneous stress

NASA Astrophysics Data System (ADS)

Tchitchekova, Deyana S.; Morthomas, Julien; Ribeiro, Fabienne; Ducher, Roland; Perez, Michel

2014-07-01

A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to ˜3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress.

A novel method for calculating the energy barriers for carbon diffusion in ferrite under heterogeneous stress.

PubMed

Tchitchekova, Deyana S; Morthomas, Julien; Ribeiro, Fabienne; Ducher, Roland; Perez, Michel

2014-07-21

A novel method for accurate and efficient evaluation of the change in energy barriers for carbon diffusion in ferrite under heterogeneous stress is introduced. This method, called Linear Combination of Stress States, is based on the knowledge of the effects of simple stresses (uniaxial or shear) on these diffusion barriers. Then, it is assumed that the change in energy barriers under a complex stress can be expressed as a linear combination of these already known simple stress effects. The modifications of energy barriers by either uniaxial traction/compression and shear stress are determined by means of atomistic simulations with the Climbing Image-Nudge Elastic Band method and are stored as a set of functions. The results of this method are compared to the predictions of anisotropic elasticity theory. It is shown that, linear anisotropic elasticity fails to predict the correct energy barrier variation with stress (especially with shear stress) whereas the proposed method provides correct energy barrier variation for stresses up to ∼3 GPa. This study provides a basis for the development of multiscale models of diffusion under non-uniform stress.

Urban sound energy reduction by means of sound barriers

NASA Astrophysics Data System (ADS)

Iordache, Vlad; Ionita, Mihai Vlad

2018-02-01

In urban environment, various heating ventilation and air conditioning appliances designed to maintain indoor comfort become urban acoustic pollution vectors due to the sound energy produced by these equipment. The acoustic barriers are the recommended method for the sound energy reduction in urban environment. The current sizing method of these acoustic barriers is too difficult and it is not practical for any 3D location of the noisy equipment and reception point. In this study we will develop based on the same method a new simplified tool for acoustic barriers sizing, maintaining the same precision characteristic to the classical method. Abacuses for acoustic barriers sizing are built that can be used for different 3D locations of the source and the reception points, for several frequencies and several acoustic barrier heights. The study case presented in the article represents a confirmation for the rapidity and ease of use of these abacuses in the design of the acoustic barriers.

Chemistry and microbiology of permeable reactive barriers for in situ groundwater clean up.

PubMed

Scherer, M M; Richter, S; Valentine, R L; Alvarez, P J

2000-01-01

Permeable reactive barriers (PRBs) are receiving a great deal of attention as an innovative, cost-effective technology for in situ clean up of groundwater contamination. A wide variety of materials are being proposed for use in PRBs, including zero-valent metals (e.g., iron metal), humic materials, oxides, surfactant-modified zeolites (SMZs), and oxygen- and nitrate-releasing compounds. PRB materials remove dissolved groundwater contaminants by immobilization within the barrier or transformation to less harmful products. The primary removal processes include: (1) sorption and precipitation, (2) chemical reaction, and (3) biologically mediated reactions. This article presents an overview of the mechanisms and factors controlling these individual processes and discusses the implications for the feasibility and long-term effectiveness of PRB technologies.

Building lipid barriers: biosynthesis of cutin and suberin.

PubMed

Pollard, Mike; Beisson, Fred; Li, Yonghua; Ohlrogge, John B

2008-05-01

Cutin and suberin are the polymer matrices for lipophilic cell wall barriers. These barriers control the fluxes of gases, water and solutes, and also play roles in protecting plants from biotic and abiotic stresses and in controlling plant morphology. Although they are ubiquitous, cutin and suberin are the least understood of the major plant extracellular polymers. The use of forward and reverse genetic approaches in Arabidopsis has led to the identification of oxidoreductase and acyltransferase genes involved in the biosynthesis of these polymers. However, major questions about the underlying polymer structure, biochemistry, and intracellular versus extracellular assembly remain to be resolved. The analysis of plant lines with modified cutins and suberins has begun to reveal the inter-relationships between the composition and function of these polymers.

Chimeric antigen receptor-modified T cells for the treatment of solid tumors: Defining the challenges and next steps☆

PubMed Central

Beatty, Gregory L.; O’Hara, Mark

2016-01-01

Chimeric antigen receptor (CAR) T cell therapy has shown promise in CD19 expressing hematologic malignancies, but how to translate this success to solid malignancies remains elusive. Effective translation of CAR T cells to solid tumors will require an understanding of potential therapeutic barriers, including factors that regulate CAR T cells expansion, persistence, trafficking, and fate within tumors. Herein, we describe the current state of CAR T cells in solid tumors; define key barriers to CAR T cell efficacy and mechanisms underlying these barriers, outline potential avenues for overcoming these therapeutic obstacles, and discuss the future of translating CAR T cells for the treatment of patients with solid malignancies. PMID:27373504

Barriers to hydroxyurea adherence and health-related quality of life in adolescents and young adults with sickle cell disease.

PubMed

Badawy, Sherif M; Thompson, Alexis A; Penedo, Frank J; Lai, Jin-Shei; Rychlik, Karen; Liem, Robert I

2017-06-01

To identify barriers to hydroxyurea adherence (negative beliefs, access, and/or recall barriers), and their relationship to adherence rates and health-related quality of life (HRQOL) among adolescents and young adults (AYA) with sickle cell disease (SCD). A cross-sectional survey was administered to 34 AYAs (12-22 years old) in SCD clinics from January to December 2015. Study measures included Brief Medication Questionnaire, Modified Morisky Adherence Scale 8-items, visual analog scale, and Patient Reported Outcomes Measurement Information System. Participants (59% male; 91% Black) had a median age of 13.5 years (IQR 12-18). Participants reported negative beliefs (32%), recall barriers (44%), and access barriers (32%). Participants with recall barriers reported worse pain (P=.02), fatigue (P=.05), and depression (P=.05). The number of adherence barriers inversely correlated with adherence level using ©MMAS-8 (r s =-.38, P=.02) and VAS dose (r s =-.25, P=.14) as well as MCV (r s =-.45, P=.01) and HbF% (r s =-.36, P=.05), suggesting higher hydroxyurea adherence in patients with fewer barriers. Patients with fewer barriers to hydroxyurea adherence were more likely to have higher adherence rates and better HRQOL scores. Routine assessment of hydroxyurea adherence and its related barriers could provide actionable information to improve adherence rates, HRQOL, and other clinical outcomes. © 2017 The Authors. European Journal of Haematology Published by John Wiley & Sons Ltd.

Modelling the endothelial blood-CNS barriers: a method for the production of robust in vitro models of the rat blood-brain barrier and blood-spinal cord barrier.

PubMed

Watson, P Marc D; Paterson, Judy C; Thom, George; Ginman, Ulrika; Lundquist, Stefan; Webster, Carl I

2013-06-18

Modelling the blood-CNS barriers of the brain and spinal cord in vitro continues to provide a considerable challenge for research studying the passage of large and small molecules in and out of the central nervous system, both within the context of basic biology and for pharmaceutical drug discovery. Although there has been considerable success over the previous two decades in establishing useful in vitro primary endothelial cell cultures from the blood-CNS barriers, no model fully mimics the high electrical resistance, low paracellular permeability and selective influx/efflux characteristics of the in vivo situation. Furthermore, such primary-derived cultures are typically labour-intensive and generate low yields of cells, limiting scope for experimental work. We thus aimed to establish protocols for the high yield isolation and culture of endothelial cells from both rat brain and spinal cord. Our aim was to optimise in vitro conditions for inducing phenotypic characteristics in these cells that were reminiscent of the in vivo situation, such that they developed into tight endothelial barriers suitable for performing investigative biology and permeability studies. Brain and spinal cord tissue was taken from the same rats and used to specifically isolate endothelial cells to reconstitute as in vitro blood-CNS barrier models. Isolated endothelial cells were cultured to expand the cellular yield and then passaged onto cell culture inserts for further investigation. Cell culture conditions were optimised using commercially available reagents and the resulting barrier-forming endothelial monolayers were characterised by functional permeability experiments and in vitro phenotyping by immunocytochemistry and western blotting. Using a combination of modified handling techniques and cell culture conditions, we have established and optimised a protocol for the in vitro culture of brain and, for the first time in rat, spinal cord endothelial cells. High yields of both CNS endothelial cell types can be obtained, and these can be passaged onto large numbers of cell culture inserts for in vitro permeability studies. The passaged brain and spinal cord endothelial cells are pure and express endothelial markers, tight junction proteins and intracellular transport machinery. Further, both models exhibit tight, functional barrier characteristics that are discriminating against large and small molecules in permeability assays and show functional expression of the pharmaceutically important P-gp efflux transporter. Our techniques allow the provision of high yields of robust sister cultures of endothelial cells that accurately model the blood-CNS barriers in vitro. These models are ideally suited for use in studying the biology of the blood-brain barrier and blood-spinal cord barrier in vitro and for pre-clinical drug discovery.

Environmental barrier material for organic light emitting device and method of making

DOEpatents

Graff, Gordon L [West Richland, WA; Gross, Mark E [Pasco, WA; Affinito, John D [Kennewick, WA; Shi, Ming-Kun [Richland, WA; Hall, Michael [West Richland, WA; Mast, Eric [Richland, WA

2003-02-18

An encapsulated organic light emitting device. The device includes a first barrier stack comprising at least one first barrier layer and at least one first polymer layer. There is an organic light emitting layer stack adjacent to the first barrier stack. A second barrier stack is adjacent to the organic light emitting layer stack. The second barrier stack has at least one second barrier layer and at least one second polymer layer. A method of making the encapsulated organic light emitting device is also provided.

Subterranean barriers, methods, and apparatuses for forming, inspecting, selectively heating, and repairing same

DOEpatents

Nickelson, Reva A.; Sloan, Paul A.; Richardson, John G.; Walsh, Stephanie; Kostelnik, Kevin M.

2009-04-07

A subterranean barrier and method for forming same are disclosed, the barrier including a plurality of casing strings wherein at least one casing string of the plurality of casing strings may be affixed to at least another adjacent casing string of the plurality of casing strings through at least one weld, at least one adhesive joint, or both. A method and system for nondestructively inspecting a subterranean barrier is disclosed. For instance, a radiographic signal may be emitted from within a casing string toward an adjacent casing string and the radiographic signal may be detected from within the adjacent casing string. A method of repairing a barrier including removing at least a portion of a casing string and welding a repair element within the casing string is disclosed. A method of selectively heating at least one casing string forming at least a portion of a subterranean barrier is disclosed.

The rational design of biomimetic skin barrier lipid formulations using biophysical methods.

PubMed

Bulsara, P A; Varlashkin, P; Dickens, J; Moore, D J; Rawlings, A V; Clarke, M J

2017-04-01

The focus of this communication was to study phospholipid-structured emulsions whose phase behaviour is modified with monoalkyl fatty amphiphiles. Ideally, these systems would mimic key physical and structural attributes observed in human stratum corneum (SC) so that they better alleviate xerotic skin conditions. Phosphatidylcholine-structured emulsions were prepared, and their phase behaviour modified with monoalkyl fatty amphiphiles. The effect of molecular volume, acyl chain length and head-group interactions was studied using a combination of physical methods. Water vapour transmission rate (WVTR) was used as a primary test to assess occlusive character. Changes in the vibrational modes observed in Fourier transform infrared (FTIR) spectroscopy and bilayer spacing measured by X-ray diffraction (XRD) were then applied to elucidate the lateral and lamellar microstructural characteristics in the systems. Water vapour transmission rate demonstrated that as the phosphatidylcholine acyl chain length increased from C14, to C18, to C22, there was a corresponding increase in occlusive character. The addition of monoalkyl fatty amphiphiles such as behenic acid, behenyl alcohol or cetostearyl alcohol to a base formulation incorporating dipalmitoyl and distearoylphosphatidylcholine (C18) was seen to further increase barrier characteristics of the emulsions. FTIR methods used to probe lipid-chain conformational ordering demonstrated that as phosphatidylcholine acyl chain lengths increased, there was a corresponding improvement in acyl chain ordering, with an increase in thermal transition temperatures. The addition of a monoalkyl fatty amphiphile resulted in conformational order and thermal transition temperature improvements trending towards those observed in stratum corneum. FTIR also demonstrated that systems containing behenic acid or behenyl alcohol exhibited features associated with orthorhombic character. X-ray diffraction data showed that addition of monoalkyl fatty amphiphile also resulted in thicker lamellar structures than when those agents are not present. The generalized approach described herein is shown to mechanistically describe the occlusive character of phospholipid-structured formulations in the presence of long-chain fatty acids or alcohols and that they exhibit characteristics mimicking those found in human SC lipids. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Developing theory-informed behaviour change interventions to implement evidence into practice: a systematic approach using the Theoretical Domains Framework

PubMed Central

2012-01-01

Background There is little systematic operational guidance about how best to develop complex interventions to reduce the gap between practice and evidence. This article is one in a Series of articles documenting the development and use of the Theoretical Domains Framework (TDF) to advance the science of implementation research. Methods The intervention was developed considering three main components: theory, evidence, and practical issues. We used a four-step approach, consisting of guiding questions, to direct the choice of the most appropriate components of an implementation intervention: Who needs to do what, differently? Using a theoretical framework, which barriers and enablers need to be addressed? Which intervention components (behaviour change techniques and mode(s) of delivery) could overcome the modifiable barriers and enhance the enablers? And how can behaviour change be measured and understood? Results A complex implementation intervention was designed that aimed to improve acute low back pain management in primary care. We used the TDF to identify the barriers and enablers to the uptake of evidence into practice and to guide the choice of intervention components. These components were then combined into a cohesive intervention. The intervention was delivered via two facilitated interactive small group workshops. We also produced a DVD to distribute to all participants in the intervention group. We chose outcome measures in order to assess the mediating mechanisms of behaviour change. Conclusions We have illustrated a four-step systematic method for developing an intervention designed to change clinical practice based on a theoretical framework. The method of development provides a systematic framework that could be used by others developing complex implementation interventions. While this framework should be iteratively adjusted and refined to suit other contexts and settings, we believe that the four-step process should be maintained as the primary framework to guide researchers through a comprehensive intervention development process. PMID:22531013

Brain delivery of proteins via their fatty acid and block copolymer modifications

PubMed Central

Yi, Xiang; Kabanov, Alexander V.

2014-01-01

It is well known that hydrophobic small molecules penetrate cell membranes better than hydrophilic molecules. Amphiphilic molecules that dissolve both in lipid and aqueous phases are best suited for membrane transport. Transport of biomacromolecules across physiological barriers, e.g. the blood-brain barrier, is greatly complicated by the unique structure and function of such barriers. Two decades ago we adopted a simple philosophy that to increase protein delivery to the brain one needs to modify this protein with hydrophobic moieties. With this general idea we began modifying proteins (antibodies, enzymes, hormones, etc.) with either hydrophobic fatty acid residues or amphiphilic block copolymer moieties, such as poy(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (pluronics or poloxamers) and more recently, poly(2-oxasolines). This simple approach has resulted in impressive successes in CNS drug delivery. We present a retrospective overview of these works initiated in the Soviet Union in 1980s, and then continued in the United States and other countries. Notably some of the early findings were later corroborated by brain pharmacokinetic data. Industrial development of several drug candidates employing these strategies has followed. Overall modification by hydrophobic fatty acids residues or amphiphilic block copolymers represents a promising and relatively safe strategy to deliver proteins to the brain. PMID:24160902

Synthesis and properties of graphene oxide/graphene nanostructures

NASA Astrophysics Data System (ADS)

Kapitanova, O. O.; Panin, G. N.; Baranov, A. N.; Kang, T. W.

2012-05-01

We report preparation of graphene oxide (GO)/graphene (G) nanostructures and their structural, optical and electrical properties. GO was synthesized through oxidation of graphite by using the modified Hummer's method, in which a long oxidation time was combined with a highly effective method for purifying the reaction products. The obtained GO was partially reduced (r-GO) by adding ascorbic acid and thermal annealing. An electrical reduction/oxidation process in r-GO under an electric field was used to form and control the GO/G nanostructures and the potential barrier at the interface. After the treatment, the ratio of the intensity of peak G (1578 cm-1) to that of peak D (1357 cm-1) in Raman spectra of the samples is increased, which is attributed to an increase in the ratio between the sp2 and sp3 regions. The electrical and the luminescence characteristics of the GO/G nanostructures were investigated.

Method of recognizing the high-speed railway noise barriers based on the distance image

NASA Astrophysics Data System (ADS)

Ma, Le; Shao, Shuangyun; Feng, Qibo; Liu, Bingqian; Kim, Chol Ryong

2016-10-01

The damage or lack of the noise barriers is one of the important hidden troubles endangering the safety of high-speed railway. In order to obtain the vibration information of the noise barriers, the online detection systems based on laser vision were proposed. The systems capture images of the laser stripe on the noise barriers and export data files containing distance information between the detection systems on the train and the noise barriers. The vibration status or damage of the noise barriers can be estimated depending on the distance information. In this paper, we focused on the method of separating the area of noise barrier from the background automatically. The test results showed that the proposed method is in good efficiency and accuracy.

The Infant Skin Barrier: Can We Preserve, Protect, and Enhance the Barrier?

PubMed Central

Telofski, Lorena S.; Morello, A. Peter; Mack Correa, M. Catherine; Stamatas, Georgios N.

2012-01-01

Infant skin is different from adult in structure, function, and composition. Despite these differences, the skin barrier is competent at birth in healthy, full-term neonates. The primary focus of this paper is on the developing skin barrier in healthy, full-term neonates and infants. Additionally, a brief discussion of the properties of the skin barrier in premature neonates and infants with abnormal skin conditions (i.e., atopic dermatitis and eczema) is included. As infant skin continues to mature through the first years of life, it is important that skin care products (e.g., cleansers and emollients) are formulated appropriately. Ideally, products that are used on infants should not interfere with skin surface pH or perturb the skin barrier. For cleansers, this can be achieved by choosing the right type of surfactant, by blending surfactants, or by blending hydrophobically-modified polymers (HMPs) with surfactants to increase product mildness. Similarly, choosing the right type of oil for emollients is important. Unlike some vegetable oils, mineral oil is more stable and is not subject to oxidation and hydrolysis. Although emollients can improve the skin barrier, more studies are needed to determine the potential long-term benefits of using emollients on healthy, full-term neonates and infants. PMID:22988452

Influences of modified bacterial cellulose nanofibers (BCNs) on structural, thermophysical, optical, and barrier properties of poly ethylene-co-vinyl acetate (EVA) nanocomposite.

PubMed

Ghadikolaei, Shila Shirdel; Omrani, Abdollah; Ehsani, Morteza

2018-04-14

The BCNs were chemically modified using acetic anhydride with the aim of improving its dispersion and interfacial adhesion. Acetylation of BCNs was confirmed by FT-IR spectroscopy. Morphology studies using TEM and SEM revealed that a reasonable dispersion of the modified BCNs in the EVA matrix was accomplished. The DSC data displayed a little shift in the T g to higher temperatures with the incorporation of both modified and unmodified BCNs. Increased thermal stability of the nanocomposites consisting acetylated BCNs was confirmed by TGA technique. DMA measurements highlighted that the storage modulus increased and the damping properties decreased for the nanocomposites with regard to the neat EVA. Copyright © 2018 Elsevier B.V. All rights reserved.

The intriguing role of Rifaximin in gut barrier chronic inflammation and in the treatment of Crohn's disease.

PubMed

Lopetuso, Loris R; Napoli, Marco; Rizzatti, Gianenrico; Gasbarrini, Antonio

2018-06-04

The gastrointestinal tract acts as a functional unit organized as a semipermeable multilayer system, in which commensal gut microbiota represents the anatomical barrier. Recently,, several studies have highlighted the involvement of gut microbiota in IBD pathogenesis, in sustaining gut barrier chronic inflammation, and in conditioning disease course and therapeutical response. This evidence provides a rationale for treating patients with gut microbiota modifiers. Among these, Rifaximin represents a non-traditional antibiotic able to act as a "eubiotic" on intestinal barrier. Area covered: The purpose of this narrative review is to explore the impact of Rifaximin on gut barrier and gut microbiota in IBD, in particular in Crohn's disease, and to analyze its potential therapeutic applications. Expert opinion: The possibility of a beneficial activity of Rifaximin in chronic intestinal inflammation and Crohn's disease has been debated and evaluated with different studies having obtained promising but still preliminary data. Larger trials are therefore needed. This gut-specific antibiotic could represent an alternative to systemic antibiotics thanks to its favorable safety profile and promising efficacy data. Rifaximin could exert, when appropriate, a synergic effect with immunomodulators in IBD, acting on both the microbial and immunological sides of gut barrier impairment.

The role of perceived barriers and objectively measured physical activity in adults aged 65-100.

PubMed

Gellert, Paul; Witham, Miles D; Crombie, Iain K; Donnan, Peter T; McMurdo, Marion E T; Sniehotta, Falko F

2015-05-01

to test the predictive utility of perceived barriers to objectively measured physical activity levels in a stratified sample of older adults when accounting for social-cognitive determinants proposed by the Theory of Planned Behaviour (TPB), and economic and demographic factors. data were analysed from the Physical Activity Cohort Scotland survey, a representative and stratified (65-80 and 80+ years; deprived and affluent) sample of 584 community-dwelling older people, resident in Tayside, Scotland. Physical activity was measured objectively by accelerometry. perceived barriers clustered around the areas of poor health, lack of interest, lack of safety and lack of access. Perceived poor health and lack of interest, but not lack of access or concerns about personal safety, predicted physical activity after controlling for demographic, economic and TPB variables. perceived person-related barriers (poor health and lack of interest) seem to be more strongly associated with physical activity levels than perceived environmental barriers (safety and access) in a large sample of older adults. Perceived barriers are modifiable and may be a target for future interventions. © The Author 2015. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

MATCON MODIFIED ASPHALT CONTAINMENT SYSTEM FOR MULTI-USE BROWNFIELDS

EPA Science Inventory

The concept of putting brownfield real estate back into safe and practical use is very appealing o both the owner and the neighborhood. Environmental regulations often preclude multi-use alterantives because traditional containment solutions rely on water barrier covers. These ar...

Impact test of a crash-energy management passenger rail car

DOT National Transportation Integrated Search

2004-04-06

On December 3, 2003, a single-car impact test was : conducted to assess the crashworthiness performance of a : modified passenger rail car. A coach car retrofitted with a : Crash Energy Management (CEM) end structure impacted a : fixed barrier at app...

Charge carrier transport and injection across organic heterojunctions

NASA Astrophysics Data System (ADS)

Tsang, Sai Wing

The discovery of highly efficient organic light-emitting diodes (OLEDs) in the 1980s has stimulated extensive research on organic semiconductors and devices. Underlying this breakthrough is the realization of the organic heterojunction (OH). Besides OLEDs, the implementation of the OH also significantly improves the power conversion efficiency in organic photovoltaic cells (OPVs). The continued technological advancements in organic electronic devices depend on the accumulation of knowledge of the intrinsic properties of organic materials and related interfaces. Among them, charge-carrier transport and carrier injection are two key factors that govern the performance of a device. This thesis mainly focuses on the charge carrier injection and transport at organic heterojunctions. The carrier transport properties of different organic materials used in this study are characterized by time-of-flight (TOF) and admittance spectroscopy (AS). An injection model is formulated by considering the carrier distribution at both sides of the interface. Using a steady-state simulation approach, the effect of accumulated charges on energy level alignment at OH is revealed. Instead of a constant injection barrier, it is found that the barrier varies with applied voltage. Moreover, an escape probability function in the injection model is modified by taking into account the total hopping rate and available hopping sites at the interface. The model predicts that the injection current at low temperature can be dramatically modified by an extremely small density of deep trap states. More importantly, the temperature dependence of the injection current is found to decrease with increasing barrier height. This suggests that extracting the barrier height from the J vs 1/T plot, as commonly employed in the literature, is problematic. These theoretical predictions are confirmed by a series of experiments on heterojunction devices with various barrier heights. In addition, the presence of deep trap states is also consistent with carrier mobility measurements at low temperature. From the point of view of application, an interface chemical doping method is proposed to engineer the carrier injection at an organic heterojunction. It is found that the injection current can be effectively increased or suppressed by introducing a thin (2 nm) doped organic layer at the interface. This technique is further extended to study the impact of an injection barrier at the OH, in OLEDs, on device performance. It is shown that a 0.3 eV injection barrier at the OH, that is normally negligible at metal/organic interface, can reduce the device efficiency by 25%. This is explained by the carrier distribution in the density-of-states at the OH. Furthermore, the carrier transport properties in a bulk heterojunction system are investigated. The bulk heterojunction consists of an interpenetrating network of a polymeric electron donor and a molecular electron acceptor. This material system has been studied in the last few years as an attractive power conversion efficiency (5% under AM 1.5) of OPV cells has been demonstrated. It is found that the electron mobility is greatly dependent on the thermal treatment of the film. Interfacial dipole effect at the heterojunction between the donor and the acceptor is proposed to be the determining factor that alters the carrier mobility in different nanoscale structures.

DFMSPH14: A C-code for the double folding interaction potential of two spherical nuclei

NASA Astrophysics Data System (ADS)

Gontchar, I. I.; Chushnyakova, M. V.

2016-09-01

This is a new version of the DFMSPH code designed to obtain the nucleus-nucleus potential by using the double folding model (DFM) and in particular to find the Coulomb barrier. The new version uses the charge, proton, and neutron density distributions provided by the user. Also we added an option for fitting the DFM potential by the Gross-Kalinowski profile. The main functionalities of the original code (e.g. the nucleus-nucleus potential as a function of the distance between the centers of mass of colliding nuclei, the Coulomb barrier characteristics, etc.) have not been modified. Catalog identifier: AEFH_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFH_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 7211 No. of bytes in distributed program, including test data, etc.: 114404 Distribution format: tar.gz Programming language: C Computer: PC and Mac Operation system: Windows XP and higher, MacOS, Unix/Linux Memory required to execute with typical data: below 10 Mbyte Classification: 17.9 Catalog identifier of previous version: AEFH_v1_0 Journal reference of previous version: Comp. Phys. Comm. 181 (2010) 168 Does the new version supersede the previous version?: Yes Nature of physical problem: The code calculates in a semimicroscopic way the bare interaction potential between two colliding spherical nuclei as a function of the center of mass distance. The height and the position of the Coulomb barrier are found. The calculated potential is approximated by an analytical profile (Woods-Saxon or Gross-Kalinowski) near the barrier. Dependence of the barrier parameters upon the characteristics of the effective NN forces (like, e.g. the range of the exchange part of the nuclear term) can be investigated. Method of solution: The nucleus-nucleus potential is calculated using the double folding model with the Coulomb and the effective M3Y NN interactions. For the direct parts of the Coulomb and the nuclear terms, the Fourier transform method is used. In order to calculate the exchange parts, the density matrix expansion method is applied. Typical running time: less than 1 minute. Reason for new version: Many users asked us how to implement their own density distributions in the DFMSPH. Now this option has been added. Also we found that the calculated Double-Folding Potential (DFP) is approximated more accurately by the Gross-Kalinowski (GK) profile. This option has been also added.

Cerium oxide nanoparticles alter the salt stress tolerance of Brassica napus L. by modifying the formation of root apoplastic barriers.

PubMed

Rossi, Lorenzo; Zhang, Weilan; Ma, Xingmao

2017-10-01

Rapidly growing global population adds significant strains on the fresh water resources. Consequently, saline water is increasingly tapped for crop irrigation. Meanwhile, rapid advancement of nanotechnology is introducing more and more engineered nanoparticles into the environment and in agricultural soils. While some negative effects of ENPs on plant health at very high concentrations have been reported, more beneficial effects of ENPs at relatively low concentrations are increasingly noticed, opening doors for potential applications of nanotechnology in agriculture. In particular, we found that cerium oxide nanoparticles (CeO 2 NPs) improved plant photosynthesis in salt stressed plants. Due to the close connections between salt stress tolerance and the root anatomical structures, we postulated that CeO 2 NPs could modify plant root anatomy and improve plant salt stress tolerance. This study aimed at testing the hypothesis with Brassica napus in the presence of CeO 2 NPs (0, 500 mg kg -1 dry sand) and/or NaCl (0, 50 mM) in a growth chamber. Free hand sections of fresh roots were taken every seven days for three weeks and the suberin lamellae development was examined under a fluorescence microscope. The results confirmed the hypothesis that CeO 2 NPs modified the formation of the apoplastic barriers in Brassica roots. In salt stressed plants, CeO 2 NPs shortened the root apoplastic barriers which allowed more Na + transport to shoots and less accumulation of Na + in plant roots. The altered Na + fluxes and transport led to better physiological performance of Brassica and may lead to new applications of nanotechnology in agriculture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Asthma Morbidity, Comorbidities, and Modifiable Factors Among Older Adults.

PubMed

Hsu, Joy; Chen, Jessica; Mirabelli, Maria C

Asthma morbidity is increased among older adults, especially older adult women. Interventions to improve asthma control in this population are not well described. The objective of this study was to identify risk factors (including modifiable factors) associated with asthma-related hospitalizations and emergency department or urgent care center visits (ED/UCV) among older adults. A secondary objective was to investigate sex differences in variables relevant to asthma control. Data were obtained from 14,076 older adults ≥65 years with active asthma participating in the 2006-2010 Behavioral Risk Factor Surveillance System Asthma Call-back Survey (a random-digit dialed survey) in 40 US states, the District of Columbia, and Puerto Rico, representative of >2.6 million persons. Weighted, adjusted logistic regression was conducted. One or more asthma-related hospitalizations in the past year were reported by 5.7% (95% confidence interval [95% CI] = 5.0% to 6.4%) of participants; 10.6% (95% CI = 9.7% to 11.5%) reported ≥1 asthma-related ED/UCV. Compared with older adults without asthma-related hospitalizations, adjusted odds were higher among those with ≥1 asthma-related hospitalization for chronic obstructive pulmonary disease (COPD), coronary artery disease, depression, cockroaches or mold in the home, and cost barriers to asthma-related health care or medication. All these factors, except for cockroaches, were associated with asthma-related ED/UCV. Compared with males, adjusted odds were higher among females for COPD, depression, obesity, and cost barriers to asthma-related health care or medication. Among older adults, asthma-related hospitalizations and ED/UCV were associated with clinical comorbidities, mold in the home, and financial barriers to asthma-related health care. Interventions addressing modifiable factors could reduce asthma morbidity among older adults. Published by Elsevier Inc.

Application of CaCu3Ti4O12 based quadruple perovskites as a promising candidate for optoelectronic devices

NASA Astrophysics Data System (ADS)

Pal, Kamalesh; Jana, Rajkumar; Dey, Arka; Ray, Partha P.; Seikh, Md Motin; Gayen, Arup

2018-05-01

We report the synthesis of nanosized (40-50 nm) CaCu3-xMnxTi4-xMnxO12 (x = 0, 0.5 and 1) quadruple perovskite (QP) semiconductor via a modified combustion method for use as Schottky barrier diode (SBD) at the Al/QP junction. The fabricated SBD is analysed on the basis of thermionic emission theory to observe its quality and some important diode parameters. For insight analysis of charge transport mechanism through metal-semiconductor junction, theory of space charge limited currents is applied and discussed in the light of parameters like carrier concentration, mobility-lifetime product and diffusion length. The Mn-doped exhibit better device performance compared to parent material.

Temperature and voltage stress dependent dielectric relaxation process of the doped Ba0.67Sr0.33TiO3 ceramics

NASA Astrophysics Data System (ADS)

Yan, Shiguang; Mao, Chaoliang; Wang, Genshui; Yao, Chunhua; Cao, Fei; Dong, Xianlin

2013-09-01

The current decay characteristic in the time domain is studied in Y3+ and Mn2+ modified Ba0.67Sr0.33TiO3 ceramics under different temperatures (25 °C-213 °C) and voltage stresses (0 V-800 V). The decay of the current is correlated with the overlapping of the relaxation process and leakage current. With respect to the inherent remarkable dielectric nonlinearity, a simple method through curve fitting is derived to differentiate these two currents. Two mechanisms of the relaxation process are proposed: a distribution of the potential barriers mode around room temperature and an electron injection mode at the elevated temperature of 110 °C.

Planning and Implementing Immunization Billing Programs at State and Local Health Departments: Barriers and Possible Solutions.

PubMed

Corriero, Rosemary; Redmon, Ginger

Before participating in a project funded by the Centers for Disease Control and Prevention, most state and local health departments (LHDs) were not seeking reimbursement or being fully reimbursed by insurance plans for the cost of immunization services (including vaccine costs and administration fees) they provided to insured patients. Centers for Disease Control and Prevention's Billables Project was designed to enable state and LHDs to bill public and private insurance plans for immunization services provided to insured patients. Identify and describe key barriers state and LHDs may encounter while planning and implementing a billing program, as well as possible solutions for overcoming those barriers. This study used reports from Billables Project participants to explore barriers they encountered when planning and implementing a billing program and steps taken to address those barriers. Thirty-eight state immunization programs. Based on project participants' reports, barriers were noted in 7 categories: (1) funding and costs, (2) staff, (3) health department characteristics, (4) third-party payers and insurance plans, (5) software, (6) patient insurance status, and (7) other barriers. Possible solutions for overcoming those barriers included hiring or seeking external help, creating billing guides and training modules, streamlining workflows, and modifying existing software systems. Overcoming barriers during planning and implementation of a billing program can be challenging for state and LHDs, but the experiences and suggestions of past Billables Project participants can help guide future billing program efforts.

Wave trapping by dual porous barriers near a wall in the presence of bottom undulation

NASA Astrophysics Data System (ADS)

Kaligatla, R. B.; Manisha; Sahoo, T.

2017-09-01

Trapping of oblique surface gravity waves by dual porous barriers near a wall is studied in the presence of step type varying bottom bed that is connected on both sides by water of uniform depths. The porous barriers are assumed to be fixed at a certain distance in front of a vertical rigid wall. Using linear water wave theory and Darcy's law for flow past porous structure, the physical problem is converted into a boundary value problem. Using eigenfunction expansion in the uniform bottom bed region and modified mild-slope equation in the varying bottom bed region, the mathematical problem is handled for solution. Moreover, certain jump conditions are used to account for mass conservation at slope discontinuities in the bottom bed profile. To understand the effect of dual porous barriers in creating tranquility zone and minimum load on the sea wall, reflection coefficient, wave forces acting on the barrier and the wall, and surface wave elevation are computed and analyzed for different values of depth ratio, porous-effect parameter, incident wave angle, gap between the barriers and wall and slope length of undulated bottom. The study reveals that with moderate porosity and suitable gap between barriers and sea wall, using dual barriers an effective wave trapping system can be developed which will exert less wave force on the barriers and the rigid wall. The proposed wave trapping system is likely to be of immense help for protecting various facilities/ infrastructures in coastal environment.

Barriers to lifestyle changes for prevention of cardiovascular disease - a survey among 40-60-year old Danes.

PubMed

Nielsen, Jesper Bo; Leppin, Anja; Gyrd-Hansen, Dort E; Jarbøl, Dorte Ejg; Søndergaard, Jens; Larsen, Pia Veldt

2017-09-12

Elimination of modifiable risk factors including unhealthy lifestyle has the potential for prevention of 80% of cardiovascular disease cases. The present study focuses on disclosing barriers for maintaining specific lifestyle changes by exploring associations between perceiving these barriers and various sociodemographic and health-related characteristics. Data were collected through a web-based questionnaire survey and included 962 respondents who initially accepted treatment for a hypothetical cardiovascular risk, and who subsequently stated that they preferred lifestyle changes to medication. Logistic regression was used to analyse associations between barriers to lifestyle changes and relevant covariates. A total of 45% of respondents were identified with at least one barrier to introducing 30 min extra exercise daily, 30% of respondents reported at least one barrier to dietary change, and among smokers at least one barrier to smoking cessation was reported by 62% of the respondents. The perception of specific barriers to lifestyle change depended on sociodemographic and health-related characteristics. We observed a considerable heterogeneity between different social groups in the population regarding a number of barriers to lifestyle change. Our study demonstrates that social inequality exists in the ability to take appropriate preventive measures through lifestyle changes to stay healthy. This finding underlines the challenge of social inequality even in populations with equal and cost-free access to health care. Our study suggests supplementing traditional public campaigns to counter cardiovascular disease by using individualized and targeted initiatives.

Feasibility of remote administration of the Fundamentals of Laparoscopic Surgery (FLS) skills test.

PubMed

Okrainec, Allan; Vassiliou, Melina; Kapoor, Andrew; Pitzul, Kristen; Henao, Oscar; Kaneva, Pepa; Jackson, Timothy; Ritter, E Matt

2013-11-01

Fundamentals of Laparoscopic Surgery (FLS) certification testing currently is offered at accredited test centers or at select surgical conferences. Maintaining these test centers requires considerable investment in human and financial resources. Additionally, it can be challenging for individuals outside North America to become FLS certified. The objective of this pilot study was to assess the feasibility of remotely administering and scoring the FLS examination using live videoconferencing compared with standard onsite testing. This parallel mixed-methods study used both FLS scoring data and participant feedback to determine the barriers to feasibility of remote proctoring for the FLS examination. Participants were tested at two accredited FLS testing centers. An official FLS proctor administered and scored the FLS exam remotely while another onsite proctor provided a live score of participants' performance. Participant feedback was collected during testing. Interrater reliabilities of onsite and remote FLS scoring data were compared using intraclass correlation coefficients (ICCs). Participant feedback was analyzed using modified grounded theory to identify themes for barriers to feasibility. The scores of the remote and onsite proctors showed excellent interrater reliability in the total FLS (ICC 0.995, CI [0.985-0.998]). Several barriers led to critical errors in remote scoring, but most were accompanied by a solution incorporated into the study protocol. The most common barrier was the chain of custody for exam accessories. The results of this pilot study suggest that remote administration of the FLS has the potential to decrease costs without altering test-taker scores or exam validity. Further research is required to validate protocols for remote and onsite proctors and to direct execution of these protocols in a controlled environment identical to current FLS test administration.

Identifying Barriers That Hinder Onsite Parental Involvement in a School-Based Health Promotion Program

PubMed Central

Garcia-Dominic, Oralia; Wray, Linda A.; Treviño, Roberto P.; Hernandez, Arthur E.; Yin, Zenong; Ulbrecht, Jan S.

2009-01-01

We investigated whether barriers to onsite parental involvement in the Bienestar Health Program Parent Component could be identified and whether participation rates could be increased by addressing these barriers. All nonparticipating parents of fourth-grade students of San Antonio Independent School District from 4 schools, which were selected randomly from 20 intervention schools in Bienestar, were invited to take part in this study. A total of 47 of 223 (21%) parents engaged in one of four focus groups offered. Parents identified barriers to their involvement in Bienestar that fit into five descriptive categories: (a) low value, (b) high cost, (c) competing family demands, (d) concerns about the program design, and (e) social role norms. The Bienestar Parent Component was then modified according to the focus group findings, which resulted in a marked increase in parental involvement from 17% to 37% overall. These findings suggest that even when parents are involved in the initial design of parent-friendly and culturally sensitive programs, as was the case for Bienestar, maximizing parental involvement may require additional assessment, identification, and remediation of barriers. PMID:19339644

Characteristics of sequential targeting of brain glioma for transferrin-modified cisplatin liposome.

PubMed

Lv, Qing; Li, Li-Min; Han, Min; Tang, Xin-Jiang; Yao, Jin-Na; Ying, Xiao-Ying; Li, Fan-Zhu; Gao, Jian-Qing

2013-02-28

Methods on how to improve the sequential targeting of glioma subsequent to passing of drug through the blood-brain barrier (BBB) have been occasionally reported. However, the characteristics involved are poorly understood. In the present study, cisplatin (Cis) liposome (lipo) was modified with transferrin (Tf) to investigate the characteristics of potential sequential targeting to glioma. In bEnd3/C6 co-culture BBB models, higher transport efficiency across the BBB and cytotoxicity in basal C6 cells induced by Cis-lipo(Tf) than Cis-lipo and Cis-solution, suggest its sequential targeting effect. Interestingly, similar liposomal morphology as that of donor compartment was first demonstrated in the receptor solution of BBB models. Meanwhile, a greater acquisition in the lysosome of bEnd3, distributed sequentially into the nucleus of C6 cells were found for the Cis-lipo(Tf). Pre-incubation of chlorpromazine and Tf inhibited this process, indicating that a clathrin-dependent endocytosis is involved in the transport of Cis-lipo(Tf) across the BBB. Copyright © 2013 Elsevier B.V. All rights reserved.

Healthcare access among circular and undocumented Mexican migrants: results from a pilot survey on the Mexico-US border

PubMed Central

Martinez-Donate, Ana P.; Zhang, Xiao; Rangel, M. Gudelia; Hovell, Melbourne; Simon, Norma-Jean; Amuedo-Dorantes, Catalina; Sipan, Carol; Guendelman, Sylvia

2014-01-01

Background Temporary and unauthorized migrants may face unique obstacles to access health care services in the U.S. Objective This study estimated levels of health care access among Mexican migrants returning to Mexico from the U.S. and factors associated with access to health care, with emphasis on the role of modifiable, enabling factors. Methods We conducted a pilot probability health care survey of migrants in the border city of Tijuana, Mexico (N=186). Results Approximately 42% of migrants reported having used health care services in the U.S. during the past year. Only 38% had a usual source of care and approximately 11% went without needed medical care in the U.S. About 71% of migrants did not have health insurance in the U.S. Lack of health insurance and transportation limitations were significantly related to various access indicators. Conclusion These results have implications for future policies and programs aimed to address modifiable health care access barriers faced by these vulnerable and underserved segments of the Mexican migrant population. PMID:25364381

Barriers to Point-of-Care Testing in India: Results from Qualitative Research across Different Settings, Users and Major Diseases

PubMed Central

Engel, Nora; Ganesh, Gayatri; Patil, Mamata; Yellappa, Vijayashree; Pant Pai, Nitika; Vadnais, Caroline; Pai, Madhukar

2015-01-01

Background Successful point-of-care testing, namely ensuring the completion of the test and treat cycle in the same encounter, has immense potential to reduce diagnostic and treatment delays, and impact patient outcomes. However, having rapid tests is not enough, as many barriers may prevent their successful implementation in point-of-care testing programs. Qualitative research on diagnostic practices may help identify such barriers across different points of care in health systems. Methods In this exploratory qualitative study, we conducted 78 semi-structured interviews and 13 focus group discussions in an urban and rural area of Karnataka, India, with healthcare providers (doctors, nurses, specialists, traditional healers, and informal providers), patients, community health workers, test manufacturers, laboratory technicians, program managers and policy-makers. Participants were purposively sampled to represent settings of hospitals, peripheral labs, clinics, communities and homes, in both the public and private sectors. Results In the Indian context, the onus is on the patient to ensure successful point-of-care testing across homes, clinics, labs and hospitals, amidst uncoordinated providers with divergent and often competing practices, in settings lacking material, money and human resources. We identified three overarching themes affecting point-of-care testing: the main theme is ‘relationships’ among providers and between providers and patients, influenced by the cross-cutting theme of ‘infrastructure’. Challenges with both result in ‘modified practices’ often favouring empirical (symptomatic) treatment over treatment guided by testing. Conclusions Even if tests can be conducted on the spot and infrastructure challenges have been resolved, relationships among providers and between patients and providers are crucial for successful point-of-care testing. Furthermore, these barriers do not act in isolation, but are interlinked and need to be examined as such. Also, a test alone has only limited power to overcome those difficulties. Test developers, policy-makers, healthcare providers and funders need to use these insights in overcoming barriers to point-of-care testing programs. PMID:26275231

Analysis of trace contamination of phthalate esters in ultrapure water using a modified solid-phase extraction procedure and automated thermal desorption-gas chromatography/mass spectrometry.

PubMed

Liu, Hsu-Chuan; Den, Walter; Chan, Shu-Fei; Kin, Kuan Tzu

2008-04-25

The present study was aimed to develop a procedure modified from the conventional solid-phase extraction (SPE) method for the analysis of trace concentration of phthalate esters in industrial ultrapure water (UPW). The proposed procedure allows UPW sample to be drawn through a sampling tube containing hydrophobic sorbent (Tenax TA) to concentrate the aqueous phthalate esters. The solid trap was then demoisturized by two-stage gas drying before subjecting to thermal desorption and analysis by gas chromatography-mass spectrometry. This process removes the solvent extraction procedure necessary for the conventional SPE method, and permits automation of the analytical procedure for high-volume analyses. Several important parameters, including desorption temperature and duration, packing quantity and demoisturizing procedure, were optimized in this study based on the analytical sensitivity for a standard mixture containing five different phthalate esters. The method detection limits for the five phthalate esters were between 36 ng l(-1) and 95 ng l(-1) and recovery rates between 15% and 101%. Dioctyl phthalate (DOP) was not recovered adequately because the compound was both poorly adsorbed and desorbed on and off Tenax TA sorbents. Furthermore, analyses of material leaching from poly(vinyl chloride) (PVC) tubes as well as the actual water samples showed that di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) were the common contaminants detected from PVC contaminated UPW and the actual UPW, as well as in tap water. The reduction of DEHP in the production processes of actual UPW was clearly observed, however a DEHP concentration of 0.20 microg l(-1) at the point of use was still being quantified, suggesting that the contamination of phthalate esters could present a barrier to the future cleanliness requirement of UPW. The work demonstrated that the proposed modified SPE procedure provided an effective method for rapid analysis and contamination identification in UPW production lines.

The Ponseti method in Latin America: initial impact and barriers to its diffusion and implementation.

PubMed

Boardman, Allison; Jayawardena, Asitha; Oprescu, Florin; Cook, Thomas; Morcuende, Jose A

2011-01-01

The Ponseti method for correcting clubfoot is a safe, effective, and minimally invasive treatment that has recently been implemented in Latin America. This study evaluates the initial impact and unique barriers to the diffusion of the Ponseti method throughout this region. Structured interviews were conducted with 30 physicians practicing the Ponseti method in three socioeconomically diverse countries: Chile, Peru and Guatemala. Since learning the Ponseti method, these physicians have treated approximately 1,740 clubfoot patients, with an estimated 1,705 (98%) patients treated using the Ponseti method, and 35 (2%) patients treated using surgical techniques. The barriers were classified into the following themes: physician education, health care system of the country, culture and beliefs of patients, physical distance and transport, financial barriers for patients, and parental compliance with the method. The results yielded several common barriers throughout Latin America including lack of physician education, physical distance to the treatment centers, and financial barriers for patients. Information from this study can be used to inform, and to implement and evaluate specific strategies to improve the diffusion of the Ponseti method for treating clubfoot throughout Latin America.

Access barriers to and unmet needs for home- and community-based services among older Korean Americans.

PubMed

Casado, Banghwa Lee; Lee, Sang E

2012-01-01

This cross-sectional survey study of 146 caregivers of older Korean Americans explored access barriers to and unmet needs for home- and community-based services (HCBS) programs (respite care, adult day care, personal care, home health, housekeeping, and transportation). Most often reported access barriers were lack of awareness and care recipient refusal. Predictors of unmet needs varied depending on the type of service, but included caregiver gender, relationship, education, caregiving duration, Medicaid coverage, English proficiency, caregiver self-efficacy, care recipient functional dependency, cognitive impairment, and caregiving hours. This study highlighted unmet needs for HCBS in Korean American communities, pointing to the pressing need for a collaborative effort to develop plans that modify and expand HCBS programs for older Korean Americans.

Damage Detection and Mitigation in Open Collaboration Applications

ERIC Educational Resources Information Center

West, Andrew G.

2013-01-01

Collaborative functionality is changing the way information is amassed, refined, and disseminated in online environments. A subclass of these systems characterized by "open collaboration" uniquely allow participants to "modify" content with low barriers-to-entry. A prominent example and our case study, English Wikipedia,…

Finding resiliency in the face of financial barriers: Development of a conceptual framework for people with cardiovascular-related chronic disease.

PubMed

Campbell, David J T; Manns, Braden J; Leblanc, Pamela; Hemmelgarn, Brenda R; Sanmartin, Claudia; King-Shier, Kathryn

2016-12-01

Patients with chronic diseases often face financial barriers to optimize their health. These financial barriers may be related to direct healthcare costs such as medications or self-monitoring supplies, or indirect costs such as transportation to medical appointments. No known framework exists to understand how financial barriers impact patients' lives or their health outcomes.We undertook a grounded theory study to develop such a framework. We used semistructured interviews with a purposive sample of participants with cardiovascular-related chronic disease (hypertension, diabetes, heart disease, or stroke) from Alberta, Canada. Interview transcripts were analyzed in triplicate, and interviews continued until saturation was reached.We interviewed 34 participants. We found that the confluence of 2 events contributed to the perception of having a financial barrier-onset of chronic disease and lack of income or health benefits. The impact of having a perceived financial barrier varied considerably. Protective, predisposing, or modifying of factors determined how impactful a financial barrier would be. An individual's particular set of factors is then shaped by their worldview. This combination of factors and lens determines one's degree of resiliency, which ultimately impacts how well they cope with their disease.The role of financial barriers is complex. How well an individual copes with their financial barriers is intimately tied to resiliency, which is related to the composite of a personal circumstances and their worldview. Our framework for understanding the experience of financial barriers can be used by both researchers and clinicians to better understand patient behavior.

Examining empirical evidence of the effect of superfluidity on the fusion barrier

NASA Astrophysics Data System (ADS)

Scamps, Guillaume

2018-04-01

Background: Recent time-dependent Hartree-Fock-Bogoliubov (TDHFB) calculations predict that superfluidity enhances fluctuations of the fusion barrier. This effect is not fully understood and not yet experimentally revealed. Purpose: The goal of this study is to empirically investigate the effect of superfluidity on the distribution width of the fusion barrier. Method: Two new methods are proposed in the present study. First, the local regression method is introduced and used to determine the barrier distribution. The second method, which requires only the calculation of an integral of the cross section, is developed to determine accurately the fluctuations of the barrier. This integral method, showing the best performance, is systematically applied to 115 fusion reactions. Results: Fluctuations of the barrier for open-shell systems are, on average, larger than those for magic or semimagic nuclei. This is due to the deformation and the superfluidity. To disentangle these two effects, a comparison is made between the experimental width and the width estimated from a model that takes into account the tunneling, the deformation, and the vibration effect. This study reveals that superfluidity enhances the fusion barrier width. Conclusions: This analysis shows that the predicted effect of superfluidity on the width of the barrier is real and is of the order of 1 MeV.

In vivo measurements of skin barrier: comparison of different methods and advantages of laser scanning microscopy

NASA Astrophysics Data System (ADS)

Patzelt, A.; Sterry, W.; Lademann, J.

2010-12-01

A major function of the skin is to provide a protective barrier at the interface between external environment and the organism. For skin barrier measurement, a multiplicity of methods is available. As standard methods, the determination of the transepidermal water loss (TEWL) as well as the measurement of the stratum corneum hydration, are widely accepted, although they offer some obvious disadvantages such as increased interference liability. Recently, new optical and spectroscopic methods have been introduced to investigate skin barrier properties in vivo. Especially, laser scanning microscopy has been shown to represent an excellent tool to study skin barrier integrity in many areas of relevance such as cosmetology, occupation, diseased skin, and wound healing.

Priorities and strategies for improving disabled women's access to maternity services when they are affected by domestic abuse: a multi-method study using concept maps.

PubMed

Bradbury-Jones, Caroline; Breckenridge, Jenna P; Devaney, John; Duncan, Fiona; Kroll, Thilo; Lazenbatt, Anne; Taylor, Julie

2015-12-28

Domestic abuse is a significant public health issue. It occurs more frequently among disabled women than those without a disability and evidence suggests that a great deal of domestic abuse begins or worsens during pregnancy. All women and their infants are entitled to equal access to high quality maternity care. However, research has shown that disabled women who experience domestic abuse face numerous barriers to accessing care. The aim of the study was to identify the priority areas for improving access to maternity services for this group of women; develop strategies for improved access and utilisation; and explore the feasibility of implementing the identified strategies. This multi-method study was the third and final part of a larger study conducted in the UK between 2012 and 2014. The study used a modified concept mapping approach and was theoretically underpinned by Andersen's model of healthcare use. Seven focus group interviews were conducted with a range of maternity care professionals (n = 45), incorporating quantitative and qualitative components. Participants ranked perceived barriers to women's access and utilisation of maternity services in order of priority using a 5-point Likert scale. Quantitative data exploration used descriptive and non-parametric analyses. In the qualitative component of each focus group, participants discussed the barriers and identified potential improvement strategies (and feasibility of implementing these). Qualitative data were analysed inductively using a framework analysis approach. The three most highly ranked barriers to women's access and utilisation of maternity services identified in the quantitative component were: 1) staff being unaware and not asking about domestic abuse and disability; 2) the impact of domestic abuse on women; 3) women's fear of disclosure. The top two priority strategies were: providing information about domestic abuse to all women and promoting non-judgemental staff attitude. These were also considered very feasible. The qualitative analysis identified a range of psychosocial and environmental barriers experienced by this group of women in accessing maternity care. Congruent with the quantitative results, the main themes were lack of awareness and fear of disclosure. Key strategies were identified as demystifying disclosure and creating physical spaces to facilitate disclosure. The study supports findings of previous research regarding the barriers that women face in accessing and utilising maternity services, particularly regarding the issue of disclosure. But the study provides new evidence on the perceived importance and feasibility of strategies to address such barriers. This is an important step in ensuring practice-based acceptability and ease with which improvement strategies might be implemented in maternity care settings.

Epigenetic regulation of cell fate reprogramming in aging and disease: A predictive computational model.

PubMed

Folguera-Blasco, Núria; Cuyàs, Elisabet; Menéndez, Javier A; Alarcón, Tomás

2018-03-01

Understanding the control of epigenetic regulation is key to explain and modify the aging process. Because histone-modifying enzymes are sensitive to shifts in availability of cofactors (e.g. metabolites), cellular epigenetic states may be tied to changing conditions associated with cofactor variability. The aim of this study is to analyse the relationships between cofactor fluctuations, epigenetic landscapes, and cell state transitions. Using Approximate Bayesian Computation, we generate an ensemble of epigenetic regulation (ER) systems whose heterogeneity reflects variability in cofactor pools used by histone modifiers. The heterogeneity of epigenetic metabolites, which operates as regulator of the kinetic parameters promoting/preventing histone modifications, stochastically drives phenotypic variability. The ensemble of ER configurations reveals the occurrence of distinct epi-states within the ensemble. Whereas resilient states maintain large epigenetic barriers refractory to reprogramming cellular identity, plastic states lower these barriers, and increase the sensitivity to reprogramming. Moreover, fine-tuning of cofactor levels redirects plastic epigenetic states to re-enter epigenetic resilience, and vice versa. Our ensemble model agrees with a model of metabolism-responsive loss of epigenetic resilience as a cellular aging mechanism. Our findings support the notion that cellular aging, and its reversal, might result from stochastic translation of metabolic inputs into resilient/plastic cell states via ER systems.

Method of sealing casings of subsurface materials management system

DOEpatents

Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

2007-02-06

Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

Current collectors for improved safety

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

Abdelmalak, Michael Naguib; Allu, Srikanth; Dudney, Nancy J.

A battery electrode assembly includes a current collector with conduction barrier regions having a conductive state in which electrical conductivity through the conduction barrier region is permitted, and a safety state in which electrical conductivity through the conduction barrier regions is reduced. The conduction barrier regions change from the conductive state to the safety state when the current collector receives a short-threatening event. An electrode material can be connected to the current collector. The conduction barrier regions can define electrical isolation subregions. A battery is also disclosed, and methods for making the electrode assembly, methods for making a battery, andmore » methods for operating a battery.« less

Experimental evaluation of optimization method for developing ultraviolet barrier coatings

NASA Astrophysics Data System (ADS)

Gonome, Hiroki; Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

2014-01-01

Ultraviolet (UV) barrier coatings can be used to protect many industrial products from UV attack. This study introduces a method of optimizing UV barrier coatings using pigment particles. The radiative properties of the pigment particles were evaluated theoretically, and the optimum particle size was decided from the absorption efficiency and the back-scattering efficiency. UV barrier coatings were prepared with zinc oxide (ZnO) and titanium dioxide (TiO2). The transmittance of the UV barrier coating was calculated theoretically. The radiative transfer in the UV barrier coating was modeled using the radiation element method by ray emission model (REM2). In order to validate the calculated results, the transmittances of these coatings were measured by a spectrophotometer. A UV barrier coating with a low UV transmittance and high VIS transmittance could be achieved. The calculated transmittance showed a similar spectral tendency with the measured one. The use of appropriate particles with optimum size, coating thickness and volume fraction will result in effective UV barrier coatings. UV barrier coatings can be achieved by the application of optical engineering.

Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

NASA Astrophysics Data System (ADS)

Samolyuk, G. D.; Osetsky, Y. N.; Stoller, R. E.

2015-10-01

We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascade production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (∼0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential. The Gao-Weber potential appears to give a more realistic description of cascade dynamics in SiC, but still has some shortcomings when the defect migration barriers are compared to the ab initio results.

Electromagnetic Saturation of Angstrom-Sized Quantum Barriers at Terahertz Frequencies

NASA Astrophysics Data System (ADS)

Bahk, Young-Mi; Kang, Bong Joo; Kim, Yong Seung; Kim, Joon-Yeon; Kim, Won Tae; Kim, Tae Yun; Kang, Taehee; Rhie, Jiyeah; Han, Sanghoon; Park, Cheol-Hwan; Rotermund, Fabian; Kim, Dai-Sik

2015-09-01

Metal-graphene-metal hybrid structures allow angstrom-scale van der Waals gaps, across which electron tunneling occurs. We squeeze terahertz electromagnetic waves through these λ /10 000 000 gaps, accompanied by giant field enhancements. Unprecedented transmission reduction of 97% is achieved with the transient voltage across the gap saturating at 5 V. Electron tunneling facilitated by the transient electric field strongly modifies the gap index, starting a self-limiting process related to the barrier height. Our work enables greater interplay between classical optics and quantum tunneling, and provides optical indices to the van der Waals gaps.

Electromagnetic Saturation of Angstrom-Sized Quantum Barriers at Terahertz Frequencies.

PubMed

Bahk, Young-Mi; Kang, Bong Joo; Kim, Yong Seung; Kim, Joon-Yeon; Kim, Won Tae; Kim, Tae Yun; Kang, Taehee; Rhie, Jiyeah; Han, Sanghoon; Park, Cheol-Hwan; Rotermund, Fabian; Kim, Dai-Sik

2015-09-18

Metal-graphene-metal hybrid structures allow angstrom-scale van der Waals gaps, across which electron tunneling occurs. We squeeze terahertz electromagnetic waves through these λ/10 000 000 gaps, accompanied by giant field enhancements. Unprecedented transmission reduction of 97% is achieved with the transient voltage across the gap saturating at 5 V. Electron tunneling facilitated by the transient electric field strongly modifies the gap index, starting a self-limiting process related to the barrier height. Our work enables greater interplay between classical optics and quantum tunneling, and provides optical indices to the van der Waals gaps.

Relevance of nanocomposite packaging on the stability of vacuum-packed dry cured ham.

PubMed

Lloret, Elsa; Fernandez, Avelina; Trbojevich, Raul; Arnau, Jacint; Picouet, Pierre A

2016-08-01

In this study effects of a novel high barrier multilayer polyamide film containing dispersed nanoclays (PAN) on the stability of vacuum packed dry-cured ham were investigated during 90days refrigerated storage in comparison with non-modified multilayer polyamide (PA) and a commercial high barrier film. Characteristic bands of the mineral in FT-IR spectra confirmed the presence of nanoclays in PAN, enhancing oxygen transmission barrier properties and UV protection. Packaging in PAN films did not originate significant changes on colour or lipid oxidation during prolonged storage of vacuum-packed dry-cured ham. Larger oxygen transmission rates in PA films caused changes in CIE b* during refrigerated storage. Ham quality was not affected by light exposition during 90days and only curing had a significant benefit on colour and TBARS, being cured samples more stable during storage in all the packages used. Packaging of dry-cured ham in PAN was equivalent to commercial high barrier films. Copyright © 2016 Elsevier Ltd. All rights reserved.

EMSC program manager survey on education of prehospital providers.

PubMed

Ngo, Thuy L; Belli, Karen; Shah, Manish I

2014-01-01

Although pediatric-specific objectives for the initial education of prehospital providers have been established, uniform implementation of these objectives and guidelines for hours of required pediatric continuing education (CE) for prehospital providers have not been established. To examine the content and number of hours of pediatric-specific education that prehospital providers receive during initial certification and recertification. Second, to identify barriers to implementing specific requirements for pediatric education of prehospital providers. Electronic surveys were sent to 55 EMS for Children (EMSC) State Partnership grantee program managers inquiring about the certification and recertification processes of prehospital providers and barriers to receiving pediatric training in each jurisdiction. We had a 91% response rate for our survey. Specified pediatric education hours exist in more states and territories for recertification (63-67%) than initial certification (41%). Limitations in funding, time, instructors, and accessibility are barriers to enhancing pediatric education. Modifying statewide policies on prehospital education and increasing hands-on training may overcome identified barriers.

MASH test 3-21 on TL-3 thrie beam transition without curb.

DOT National Transportation Integrated Search

2013-01-01

This project evaluated the impact performance of a modified TxDOT thrie beam transition to rigid : concrete barrier without a curb element below the transition rail. In a previous test described in TxDOT : Research Report 0-4564, a thrie beam transit...

The role of the intestinal microvasculature in inflammatory bowel disease: studies with a modified Caco-2 model including endothelial cells resembling the intestinal barrier in vitro.

PubMed

Kasper, Jennifer Y; Hermanns, Maria Iris; Cavelius, Christian; Kraegeloh, Annette; Jung, Thomas; Danzebrink, Rolf; Unger, Ronald E; Kirkpatrick, Charles James

The microvascular endothelium of the gut barrier plays a crucial role during inflammation in inflammatory bowel disease. We have modified a commonly used intestinal cell model based on the Caco-2 cells by adding microvascular endothelial cells (ISO-HAS-1). Transwell filters were used with intestinal barrier-forming Caco-2 cells on top and the ISO-HAS-1 on the bottom of the filter. The goal was to determine whether this coculture mimics the in vivo situation more closely, and whether the model is suitable to evaluate interactions of, for example, prospective nanosized drug vehicles or contrast agents with this coculture in a physiological and inflamed state as it would occur in inflammatory bowel disease. We monitored the inflammatory responsiveness of the cells (release of IL-8, soluble intercellular adhesion molecule 1, and soluble E-selectin) after exposure to inflammatory stimuli (lipopolysaccharide, TNF-α, INF-γ, IL1-β) and a nanoparticle (Ba/Gd: coprecipitated BaSO 4 and Gd(OH) 3 ), generally used as contrast agents. The barrier integrity of the coculture was evaluated via the determination of transepithelial electrical resistance and the apparent permeability coefficient (P app ) of NaFITC. The behavior of the coculture Caco-1/ISO-HAS-1 was compared to the respective monocultures Caco-2 and ISO-HAS-1. Based on transepithelial electrical resistance, the epithelial barrier integrity of the coculture remained stable during incubation with all stimuli, whereas the P app decreased after exposure to the cytokine mixture (TNF-α, INF-γ, IL1-β, and Ba/Gd). Both the endothelial and epithelial monocultures showed a high inflammatory response in both the upper and lower transwell-compartments. However, in the coculture, inflammatory mediators were only detected on the epithelial side and not on the endothelial side. Thus in the coculture, based on the P app , the epithelial barrier appears to prevent a potential inflammatory overreaction in the underlying endothelial cells. In summary, this coculture model exhibits in vivo-like features, which cannot be observed in conventional monocultures, making the former more suitable to study interactions with external stimuli.

Implementation of a cystic fibrosis lung transplant referral patient decision aid in routine clinical practice: an observational study.

PubMed

Stacey, Dawn; Vandemheen, Katherine L; Hennessey, Rosamund; Gooyers, Tracy; Gaudet, Ena; Mallick, Ranjeeta; Salgado, Josette; Freitag, Andreas; Berthiaume, Yves; Brown, Neil; Aaron, Shawn D

2015-02-07

The decision to have lung transplantation as treatment for end-stage lung disease from cystic fibrosis (CF) has benefits and serious risks. Although patient decision aids are effective interventions for helping patients reach a quality decision, little is known about implementing them in clinical practice. Our study evaluated a sustainable approach for implementing a patient decision aid for adults with CF considering referral for lung transplantation. A prospective pragmatic observational study was guided by the Knowledge-to-Action Framework. Healthcare professionals in all 23 Canadian CF clinics were eligible. We surveyed participants regarding perceived barriers and facilitators to patient decision aid use. Interventions tailored to address modifiable identified barriers included training, access to decision aids, and conference calls. The primary outcome was >80% use of the decision aid in year 2. Of 23 adult CF clinics, 18 participated (78.2%) and 13 had healthcare professionals attend training. Baseline barriers were healthcare professionals' inadequate knowledge for supporting patients making decisions (55%), clarifying patients' values for outcomes of options (58%), and helping patients handle conflicting views of others (71%). Other barriers were lack of time (52%) and needing to change how transplantation is discussed (42%). Baseline facilitators were healthcare professionals feeling comfortable discussing bad transplantation outcomes (74%), agreeing the decision aid would be easy to experiment with (71%) and use in the CF clinic (87%), and agreeing that using the decision aid would not require reorganization of the CF clinic (90%). After implementing the decision aid with interventions tailored to the barriers, decision aid use increased from 29% at baseline to 85% during year 1 and 92% in year 2 (p < 0.001). Compared to baseline, more healthcare professionals at the end of the study were confident in supporting decision-making (p = 0.03) but continued to feel inadequate ability with supporting patients to handle conflicting views (p = 0.01). Most Canadian CF clinics agreed to participate in the study. Interventions were used to target identified modifiable barriers to using the patient decision aid in routine CF clinical practice. CF clinics reported using it with almost all patients in the second year.

Single ricin detection by atomic force microscopy chemomechanical mapping

NASA Astrophysics Data System (ADS)

Chen, Guojun; Zhou, Jianfeng; Park, Bosoon; Xu, Bingqian

2009-07-01

The authors report on a study of detecting ricin molecules immobilized on chemically modified Au (111) surface by chemomechanically mapping the molecular interactions with a chemically modified atomic force microscopy (AFM) tip. AFM images resolved the different fold-up conformations of single ricin molecule as well as their intramolecule structure of A- and B-chains. AFM force spectroscopy study of the interaction indicates that the unbinding force has a linear relation with the logarithmic force loading rate, which agrees well with calculations using one-barrier bond dissociation model.

A Probabilistic Model for Predicting Attenuation of Viruses During Percolation in Unsaturated Natural Barriers

NASA Astrophysics Data System (ADS)

Faulkner, B. R.; Lyon, W. G.

2001-12-01

We present a probabilistic model for predicting virus attenuation. The solution employs the assumption of complete mixing. Monte Carlo methods are used to generate ensemble simulations of virus attenuation due to physical, biological, and chemical factors. The model generates a probability of failure to achieve 4-log attenuation. We tabulated data from related studies to develop probability density functions for input parameters, and utilized a database of soil hydraulic parameters based on the 12 USDA soil categories. Regulators can use the model based on limited information such as boring logs, climate data, and soil survey reports for a particular site of interest. Plackett-Burman sensitivity analysis indicated the most important main effects on probability of failure to achieve 4-log attenuation in our model were mean logarithm of saturated hydraulic conductivity (+0.396), mean water content (+0.203), mean solid-water mass transfer coefficient (-0.147), and the mean solid-water equilibrium partitioning coefficient (-0.144). Using the model, we predicted the probability of failure of a one-meter thick proposed hydrogeologic barrier and a water content of 0.3. With the currently available data and the associated uncertainty, we predicted soils classified as sand would fail (p=0.999), silt loams would also fail (p=0.292), but soils classified as clays would provide the required 4-log attenuation (p=0.001). The model is extendible in the sense that probability density functions of parameters can be modified as future studies refine the uncertainty, and the lightweight object-oriented design of the computer model (implemented in Java) will facilitate reuse with modified classes. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.

Asthma-Related School Absenteeism, Morbidity, and Modifiable Factors

PubMed Central

Hsu, Joy; Qin, Xiaoting; Beavers, Suzanne F.; Mirabelli, Maria C.

2016-01-01

Background Asthma is a leading cause of chronic disease-related school absenteeism. Little data exist on how information on absenteeism might be used to identify children for interventions to improve asthma control. This study investigated how asthma-related absenteeism was associated with asthma control, exacerbations, and associated modifiable risk factors using a sample of children from 35 states and the District of Columbia. Methods The Behavioral Risk Factor Surveillance System Child Asthma Call-back Survey is a random-digit dialing survey designed to assess the health and experiences of children aged 0–17 years with asthma. During 2014–2015, multivariate analyses were conducted using 2006–2010 data to compare children with and without asthma-related absenteeism with respect to clinical, environmental, and financial measures. These analyses controlled for sociodemographic and clinical characteristics. Results Compared to children without asthma-related absenteeism, children who missed any school because of asthma were more likely to have not well controlled or very poorly controlled asthma (prevalence ratio: 1.50; 95% CI: 1.34–1.69) and visit an emergency department or urgent care center for asthma (prevalence ratio: 3.27; 95% CI: 2.44–4.38). Mold in the home and cost as a barrier to asthma-related health care were also significantly associated with asthma-related absenteeism. Conclusions Missing any school because of asthma was associated with suboptimal asthma control, urgent or emergent asthma-related health care utilization, mold in the home, and financial barriers to asthma-related health care. Further understanding of asthma-related absenteeism could establish how to most effectively use absenteeism information as a health status indicator. PMID:26873793

The prevalence of medication nonadherence in post-myocardial infarction survivors and its perceived barriers and psychological correlates: a cross-sectional study in a cardiac health facility in Malaysia

PubMed Central

Ganasegeran, Kurubaran; Rashid, Abdul

2017-01-01

Background Although evidence-based practice has shown the benefits of prescribed cardioprotective drugs in post-myocardial infarction (MI) survivors, adherence rates remain suboptimal. The aim of this study was to determine the prevalence and factors associated with medication nonadherence among post-MI survivors in Malaysia. Materials and methods This cross-sectional study was conducted from February to September 2016 among 242 post-MI survivors aged 24–96 years at the cardiology outpatient clinic in a Malaysian cardiac specialist center. The study utilized an interviewer-administered questionnaire that consisted of items adapted and modified from the validated Simplified Medication Adherence Questionnaire, sociodemographics, health factors, perceived barriers, and novel psychological attributes, which employed the modified Confusion, Hubbub, and Order Scale and the Verbal Denial in Myocardial Infarction questionnaire. Results The prevalence of medication nonadherence was 74%. In the multivariable model, denial of illness (AOR 1.2, 95% CI 0.9–1.8; P=0.032), preference to traditional medicine (AOR 8.7, 95% CI 1.1–31.7; P=0.044), lack of information about illness (AOR 3.3, 95% CI 1.1–10.6; P=0.045), fear of side effects (AOR 6.4, 95% CI 2.5–16.6; P<0.001), and complex regimen (AOR 5.2, 95% CI 1.9–14.2; P=0.001) were statistically significant variables associated with medication nonadherence. Conclusion The relatively higher medication-nonadherence rate in this study was associated with patient-, provider-, and therapy-related factors and the novel psychological attribute denial of illness. Future research should explore these factors using robust methodological techniques to determine temporality among these factors. PMID:29263654

Method for applying a diffusion barrier interlayer for high temperature components

DOEpatents

Wei, Ronghua; Cheruvu, Narayana S.

2016-03-08

A coated substrate and a method of forming a diffusion barrier coating system between a substrate and a MCrAl coating, including a diffusion barrier coating deposited onto at least a portion of a substrate surface, wherein the diffusion barrier coating comprises a nitride, oxide or carbide of one or more transition metals and/or metalloids and a MCrAl coating, wherein M includes a transition metal or a metalloid, deposited on at least a portion of the diffusion barrier coating, wherein the diffusion barrier coating restricts the inward diffusion of aluminum of the MCrAl coating into the substrate.

Subsurface materials management and containment system, components thereof and methods relating thereto

DOEpatents

Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

2006-04-18

Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

Measuring the barriers against seeking consultation for urinary incontinence among Middle Eastern women.

PubMed

El-Azab, Ahmed S; Shaaban, Omar M

2010-01-27

Existing questionnaires to assess barriers against consultation for urinary incontinence (UI) are not appropriate for use in the Middle East culture. The aim of this study was to explore barriers against seeking help for UI and introducing a questionnaire that assess these barriers among those women. This is important before proceeding to any educational programs or having interval clinical audits to help incontinent women. 1- Screening for UI. Women - aged 20 years and older, attending the outpatient Urology and Gynaecology clinics were invited to participate and interviewed by a research nurse. The UDI-6 was administered to assess the presence and type of UI. Women with UI as their chief complaint were excluded. 2- Interviewing study subjects for possible barriers. Subjects who had UI - as determined by the UDI-6-were first asked an open question "what prevented you from seeking medical consultation for urine leakage?"." They were then asked the proposed questions to assess possible barriers. We developed a preliminary questionnaire based on a review of reasons for not seeking incontinence care from the literature and the response of UI sufferers to the open question in this study. The questionnaire was modified many times to reach this final form. 3- Pilot Study to assess characteristics of the questionnaire. Validity and reliability of the final version of the questionnaire were assessed in a small pilot study including 36 women who completed questionnaire at initial visit and again after 2 weeks. Of the 1231 subjects who agreed to participate in the study, 348 reported having UI. About 80% of incontinent women have never sought medical advice. Factors significantly associated with seeking help were husband encouragement, prayer affection and having severe UI. Common barriers were embarrassment and assuming UI as a normal part of aging. A pilot study included 36 women to assess the psychometric properties of the questionnaire after modifying it. The number of missing or not interpretable responses per item ranged from 2.2% to 8.7%. Internal consistency of the items was good. The test-retest reliability of individual items of the questionnaire was variable, with weighted kappa statistics ranging from 0.32 to 0.94 (median, 0.76, p 0.000). Preliminary data on our proposed questionnaire show that it is an easy to administer, stable and suits the Middle Eastern culture.

Exploring barriers and facilitators to the clinical use of virtual reality for post-stroke unilateral spatial neglect assessment.

PubMed

Ogourtsova, Tatiana; Archambault, Philippe S; Lamontagne, Anouk

2017-11-07

Hemineglect, defined as a failure to attend to the contralesional side of space, is a prevalent and disabling post-stroke deficit. Conventional hemineglect assessments lack sensitivity as they contain mainly non-functional tasks performed in near-extrapersonal space, using static, two-dimensional methods. This is of concern given that hemineglect is a strong predictor for functional deterioration, limited post-stroke recovery, and difficulty in community reintegration. With the emerging field of virtual reality, several virtual tools have been proposed and have reported better sensitivity in neglect-related deficits detection than conventional methods. However, these and future virtual reality-based tools are yet to be implemented in clinical practice. The present study aimed to explore the barriers/facilitators perceived by clinicians in the use of virtual reality for hemineglect assessment; and to identify features of an optimal virtual assessment. A qualitative descriptive process, in the form of focus groups, self-administered questionnaire and individual interviews was used. Two focus groups (n = 11 clinicians) were conducted and experts in the field (n = 3) were individually interviewed. Several barriers and facilitators, including personal, institutional, client suitability, and equipment factors, were identified. Clinicians and experts in the field reported numerous features for the virtual tool optimization. Factors identified through this study lay the foundation for the development of a knowledge translation initiative towards an implementation of a virtual assessment for hemineglect. Addressing the identified barriers/facilitators during implementation and incorporating the optimal features in the design of the virtual assessment could assist and promote its eventual adoption in clinical settings. Implications for rehabilitation A multimodal and active knowledge translation intervention built on the presently identified modifiable factors is suggested to be implemented to support the clinical integration of a virtual reality-based assessment for post-stroke hemineglect. To amplify application and usefulness of a virtual-reality based tool in the assessment of post-stroke hemineglect, optimal features identified in the present study should be incorporated in the design of such technology.

Absence of Nosocomial Transmission of Imported Lassa Fever during Use of Standard Barrier Nursing Methods.

PubMed

Grahn, Anna; Bråve, Andreas; Tolfvenstam, Thomas; Studahl, Marie

2018-06-01

Nosocomial transmission of Lassa virus (LASV) is reported to be low when care for the index patient includes proper barrier nursing methods. We investigated whether asymptomatic LASV infection occurred in healthcare workers who used standard barrier nursing methods during the first 15 days of caring for a patient with Lassa fever in Sweden. Of 76 persons who were defined as having been potentially exposed to LASV, 53 provided blood samples for detection of LASV IgG. These persons also responded to a detailed questionnaire to evaluate exposure to different body fluids from the index patient. LASV-specific IgG was not detected in any of the 53 persons. Five of 53 persons had not been using proper barrier nursing methods. Our results strengthen the argument for a low risk of secondary transmission of LASV in humans when standard barrier nursing methods are used and the patient has only mild symptoms.

Fingolimod promotes blood-nerve barrier properties in vitro.

PubMed

Nishihara, Hideaki; Maeda, Toshihiko; Sano, Yasuteru; Ueno, Maho; Okamoto, Nana; Takeshita, Yukio; Shimizu, Fumitaka; Koga, Michiaki; Kanda, Takashi

2018-04-01

The main effect of fingolimod is thought to be functional antagonism of lymphocytic S1P1 receptors and the prevention of lymphocyte egress from lymphoid tissues, thereby reducing lymphocyte infiltration into the nervous system. However, a growing number of reports suggest that fingolimod also has a direct effect on several cell types in the nervous system. Although we previously reported that fingolimod enhances blood-brain barrier (BBB) functions, there have been no investigations regarding the blood-nerve barrier (BNB). In this study, we examine how fingolimod affects the BNB. An immortalized human peripheral nerve microvascular endothelial cell line (HPnMEC) was used to evaluate BNB barrier properties. We examined tight junction proteins and barrier functions of HPnMECs in conditioned medium with or without fingolimod-phosphate and blood sera from patients with typical chronic inflammatory demyelinating polyneuropathy (CIDP). Incubation with fingolimod-phosphate increased levels of claudin-5 mRNA and protein as well as TEER values in HPnMECs. Conversely, typical CIDP sera decreased claudin-5 mRNA/protein levels and TEER values in HPnMECs; however, pretreatment with fingolimod-phosphate inhibited the effects of the typical CIDP sera. Fingolimod-phosphate directly modifies the BNB and enhances barrier properties. This mechanism may be a viable therapeutic target for CIDP, and fingolimod may be useful in patients with typical CIDP who have severe barrier disruption.

Identifying barriers to the provision of bystander cardiopulmonary resuscitation (CPR) in high-risk regions: a qualitative review of emergency calls.

PubMed

Case, Rosalind; Cartledge, Susie; Siedenburg, Josine; Smith, Karen; Straney, Lahn; Barger, Bill; Finn, Judith; Bray, Janet E

2018-06-01

Understanding regional variation in bystander cardiopulmonary resuscitation (CPR) is important to improving out-of-hospital cardiac arrest (OHCA) survival. In this study we aimed to identify barriers to providing bystander CPR in regions with low rates of bystander CPR and where OHCA was recognised in the emergency call. We retrospectively reviewed emergency calls for adults in regions of low bystander CPR in the Australian state of Victoria. Included calls were those where OHCA was identified during the call but no bystander CPR was given. A thematic content analysis was independently conducted by two investigators. Saturation of themes was reached after listening to 139 calls. Calls progressed to the point of compression instructions before EMS arrival in only 26 (18.7%) of cases. Three types of barriers were identified: procedural barriers (time lost due to language barriers and communication issues; telephone problems), CPR knowledge (skill deficits; perceived benefit) and personal factors (physical frailty or disability; patient position; emotional factors). A range of factors are associated with barriers to delivering bystander CPR even in the presence of dispatcher instructions -some of which are modifiable. To overcome these barriers in high-risk regions, targeted public education needs to provide information about what occurs in an emergency call, how to recognise an OHCA and to improve CPR knowledge and skills. Copyright © 2018. Published by Elsevier B.V.

Barriers to Treatment Among African Americans with Obsessive-Compulsive Disorder

PubMed Central

Williams, M.T.; Domanico, J.; Marques, L.; Leblanc, N.J.; Turkheimer, E.

2012-01-01

African Americans are underrepresented in OCD treatment centers and less likely to experience a remission of symptoms. This study examines the barriers that prevent African Americans with OCD from receiving treatment. Seventy-one adult African Americans with OCD were recruited and administered the modified Barriers to Treatment Participation Scale (BTPS) and the Barriers to Treatment Questionnaire (BTQ). Comparing the BTQ between a European American Internet sample (N=108) and the African American OCD sample (N=71) revealed barriers unique to African Americans, including not knowing where to find help and concerns about discrimination. A Mokken Scale Analysis of the BTPS in the African American participants identified seven major barriers, including the cost of treatment, stigma, fears of therapy, believing that the clinician will be unable to help, feeling no need for treatment, and treatment logistics (being too busy or treatment being too inconvenient). Pearson and point-biserial correlations of the scales and demographic and psychological variables were conducted. Significant relationships emerged between age, gender, income, education, insurance status, and ethnic affirmation/belonging among several of the Mokken scales. A one-way ANOVA demonstrated that concerns about cost were significantly greater for those without insurance, versus those with public or private plans. Suggestions for overcoming barriers are presented, including community education, affordable treatment options, and increasing cultural competence among mental health providers. PMID:22410094

Temperature dependent current-voltage characteristics of Au/n-Si Schottky barrier diodes and the effect of transition metal oxides as an interface layer

NASA Astrophysics Data System (ADS)

Mahato, Somnath; Puigdollers, Joaquim

2018-02-01

Temperature dependent current-voltage (I‒V) characteristics of Au/n-type silicon (n-Si) Schottky barrier diodes have been investigated. Three transition metal oxides (TMO) are used as an interface layer between gold and silicon. The basic Schottky diode parameters such as ideality factor (n), barrier height (ϕb 0) and series resistance (Rs) are calculated and successfully explained by the thermionic emission (TE) theory. It has been found that ideality factor decreased and barrier height increased with increased of temperature. The conventional Richardson plot of ln(I0/T2) vs. 1000/T is determined the activation energy (Ea) and Richardson constant (A*). Whereas value of 'A*' is much smaller than the known theoretical value of n-type Si. The temperature dependent I-V characteristics obtained the mean value of barrier height (ϕb 0 bar) and standard deviation (σs) from the linear plot of ϕap vs. 1000/T. From the modified Richardson plot of ln(I0/T2) ˗ (qσ)2/2(kT)2 vs. 1000/T gives Richardson constant and homogeneous barrier height of Schottky diodes. Main observation in this present work is the barrier height and ideality factor shows a considerable change but the series resistance value exhibits negligible change due to TMO as an interface layer.

Surfactants have multi-fold effects on skin barrier function.

PubMed

Lemery, Emmanuelle; Briançon, Stéphanie; Chevalier, Yves; Oddos, Thierry; Gohier, Annie; Boyron, Olivier; Bolzinger, Marie-Alexandrine

2015-01-01

The stratum corneum (SC) is responsible for the barrier properties of the skin and the role of intercorneocyte skin lipids, particularly their structural organization, in controlling SC permeability is acknowledged. Upon contacting the skin, surfactants interact with the SC components leading to barrier damage. To improve knowledge of the effect of several classes of surfactant on skin barrier function at three different levels. The influence of treatments of human skin explants with six non-ionic and four ionic surfactant solutions on the physicochemical properties of skin was investigated. Skin surface wettability and polarity were assessed through contact angle measurements. Infrared spectroscopy allowed monitoring the SC lipid organization. The lipid extraction potency of surfactants was evaluated thanks to HPLC-ELSD assays. One anionic and one cationic surfactant increased the skin polarity by removing the sebaceous and epidermal lipids and by disturbing the organization of the lipid matrix. Another cationic surfactant displayed a detergency effect without disturbing the skin barrier. Several non-ionic surfactants disturbed the lipid matrix organization and modified the skin wettability without any extraction of the skin lipids. Finally two non-ionic surfactants did not show any effect on the investigated parameters or on the skin barrier. The polarity, the organization of the lipid matrix and the lipid composition of the skin allowed describing finely how surfactants can interact with the skin and disturb the skin barrier function.

A qualitative study into the perceived barriers of accessing healthcare among a vulnerable population involved with a community centre in Romania.

PubMed

George, Siân; Daniels, Katy; Fioratou, Evridiki

2018-04-03

Minority vulnerable communities, such as the European Roma, often face numerous barriers to accessing healthcare services, resulting in negative health outcomes. Both these barriers and outcomes have been reported extensively in the literature. However, reports on barriers faced by European non-Roma native communities are limited. The "Health Care Access Barriers" (HCAB) model identifies pertinent financial, structural and cognitive barriers that can be measured and potentially modified. The present study thus aims to explore the barriers to accessing healthcare for a vulnerable population of mixed ethnicity from a charity community centre in Romania, as perceived by the centre's family users and staff members, and assess whether these reflect the barriers identified from the HCAB model. Eleven community members whose children attend the centre and seven staff members working at the centre participated in face-to-face semi-structured interviews, exploring personal experiences and views on accessing healthcare. The interviews were transcribed and analysed using an initial deductive and secondary inductive approach to identify HCAB themes and other emerging themes and subthemes. Identified themes from both groups aligned with HCAB's themes of financial, structural and cognitive barriers and emergent subthemes important to the specific population were identified. Specifically, financial barriers related mostly to health insurance and bribery issues, structural barriers related mostly to service availability and accessibility, and cognitive barriers related mostly to healthcare professionals' attitudes and discrimination and the vulnerable population's lack of education and health literacy. A unique theme of psychological barriers emerged from both groups with associated subthemes of mistrust, hopelessness, fear and anxiety of this vulnerable population. The current study highlights healthcare access barriers to a vulnerable non-Roma native population involved with a charity community centre in Romania. The "Healthcare Access Barriers for Vulnerable Populations" (HABVP) model is proposed as an adaption to the existing HCAB model to account for the unique perceived barriers to healthcare for this population. Recommendations for future resolution of these identified barriers are proposed.

Multipolar Ewald Methods, 2: Applications Using a Quantum Mechanical Force Field

PubMed Central

2015-01-01

A fully quantum mechanical force field (QMFF) based on a modified “divide-and-conquer” (mDC) framework is applied to a series of molecular simulation applications, using a generalized Particle Mesh Ewald method extended to multipolar charge densities. Simulation results are presented for three example applications: liquid water, p-nitrophenylphosphate reactivity in solution, and crystalline N,N-dimethylglycine. Simulations of liquid water using a parametrized mDC model are compared to TIP3P and TIP4P/Ew water models and experiment. The mDC model is shown to be superior for cluster binding energies and generally comparable for bulk properties. Examination of the dissociative pathway for dephosphorylation of p-nitrophenylphosphate shows that the mDC method evaluated with the DFTB3/3OB and DFTB3/OPhyd semiempirical models bracket the experimental barrier, whereas DFTB2 and AM1/d-PhoT QM/MM simulations exhibit deficiencies in the barriers, the latter for which is related, in part, to the anomalous underestimation of the p-nitrophenylate leaving group pKa. Simulations of crystalline N,N-dimethylglycine are performed and the overall structure and atomic fluctuations are compared with the experiment and the general AMBER force field (GAFF). The QMFF, which was not parametrized for this application, was shown to be in better agreement with crystallographic data than GAFF. Our simulations highlight some of the application areas that may benefit from using new QMFFs, and they demonstrate progress toward the development of accurate QMFFs using the recently developed mDC framework. PMID:25691830

Temperature dependent current transport of Pd/ZnO nanowire Schottky diodes

NASA Astrophysics Data System (ADS)

Gayen, R. N.; Bhattacharyya, S. R.; Jana, P.

2014-09-01

Zinc oxide (ZnO) nanowire based Schottky barrier diodes are fabricated by depositing Pd metal contact on top of vertically well-aligned ZnO nanowire arrays. A vertical array of ZnO nanowires on indium tin oxide (ITO) coated glass substrates is synthesized by hybrid wet chemical route. Scanning electron microscopy (SEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) measurement confirm the formation of stoichiometric well-aligned hexagonal (h-ZnO) nanowire arrays with wurtzite structure. Temperature dependent current-voltage (I-V) measurements on palladium-ZnO (Pd/ZnO) nanowire Schottky junctions in the temperature range 303-383 K exhibit excellent rectifying character. From these nonlinear I-V plots, different electrical parameters of diode-like reverse saturation current, barrier height and ideality factor are determined as a function of temperature assuming pure thermionic emission model. The ideality factor is found to decrease while the barrier height increases with the increase in temperature. The series resistance values calculated from Cheung’s functions also show temperature dependency. Such behavior can be attributed to the presence of defects that traps carriers, and barrier height inhomogeneity at the interface of the barrier junction. After barrier height inhomogeneity correction, considering a Gaussian distributed barrier height fluctuation across the Pd/ZnO interface, the estimated values of mean barrier height and modified Richardson constant are more closely matched to the theoretically predicted value for Pd/ZnO Schottky barrier diodes. The variation of density of interface states as a function of interface state energy is also calculated.

Where to restore ecological connectivity? Detecting barriers and quantifying restoration benefits.

PubMed

McRae, Brad H; Hall, Sonia A; Beier, Paul; Theobald, David M

2012-01-01

Landscape connectivity is crucial for many ecological processes, including dispersal, gene flow, demographic rescue, and movement in response to climate change. As a result, governmental and non-governmental organizations are focusing efforts to map and conserve areas that facilitate movement to maintain population connectivity and promote climate adaptation. In contrast, little focus has been placed on identifying barriers-landscape features which impede movement between ecologically important areas-where restoration could most improve connectivity. Yet knowing where barriers most strongly reduce connectivity can complement traditional analyses aimed at mapping best movement routes. We introduce a novel method to detect important barriers and provide example applications. Our method uses GIS neighborhood analyses in conjunction with effective distance analyses to detect barriers that, if removed, would significantly improve connectivity. Applicable in least-cost, circuit-theoretic, and simulation modeling frameworks, the method detects both complete (impermeable) barriers and those that impede but do not completely block movement. Barrier mapping complements corridor mapping by broadening the range of connectivity conservation alternatives available to practitioners. The method can help practitioners move beyond maintaining currently important areas to restoring and enhancing connectivity through active barrier removal. It can inform decisions on trade-offs between restoration and protection; for example, purchasing an intact corridor may be substantially more costly than restoring a barrier that blocks an alternative corridor. And it extends the concept of centrality to barriers, highlighting areas that most diminish connectivity across broad networks. Identifying which modeled barriers have the greatest impact can also help prioritize error checking of land cover data and collection of field data to improve connectivity maps. Barrier detection provides a different way to view the landscape, broadening thinking about connectivity and fragmentation while increasing conservation options.

Barriers, Benefits, and Behaviors Related to Breakfast Consumption Among Rural Adolescents.

PubMed

Hearst, Mary O; Shanafelt, Amy; Wang, Qi; Leduc, Robert; Nanney, Marilyn S

2016-03-01

We sought to determine if perceived barriers, benefits, and modifiable behaviors support or interfere with breakfast consumption in a racially and economically diverse rural high school population. The participants were 832 Minnesota adolescents from 16 rural high schools. We used baseline data from a group randomized trial aimed at increasing school breakfast participation through policy and environmental-level school changes. Students completed an online survey asking about demographics, breakfast eating behaviors, and the barriers and benefits of eating as it relates to school performance. Bivariate and multivariate logistic regression, accounting for clustering by school, was performed using SAS. Each scale was modeled independently. Participants were 9th and 10th grade students, 36% free/reduced-price lunch (FRL), 30% non-White, and 55% female. Breakfast skippers compared to nonbreakfast skippers reported fewer school related benefits and beliefs and more barriers to eating breakfast (p < .01). Adjusted models revealed students reported more positive beliefs (OR = 0.78, 95% CI = 0.73-0.83), more benefits (OR = 0.95, 95% CI = 0.93-0.97) and fewer barriers (OR = 0.85, 95% CI = 0.82-0.87) and were less likely to skip breakfast. Future intervention research should focus on alleviating barriers and enhancing education around the school related benefits of eating breakfast. © 2016, American School Health Association.

Controlled thermoelectric response of a tunable Rashba coupled metal-insulator-superconductor junction

NASA Astrophysics Data System (ADS)

Kapri, Priyadarshini; Adhikary, Priyanka; Sinha, Shubham; Basu, Saurabh

2018-05-01

Thermoelectric effect for metal, insulator and the superconductor junctions has been studied with Rashba spin-orbit coupling (RSOC) being present at the interfaces via modified Blonder-Tinkham-Klapwijk (BTK) theory. We find that the thermopower, as a function of an effective barrier potential that characterizes the intermediate insulating layer, displays an oscillatory behavior. Interesting interplay between the strength of RSOC and the effective barrier potential has been carried out in details in this regard. For specific ranges of the effective barrier potential, RSOC enhances the thermopower, while the reverse happens for other values. Moreover it is found that the effective barrier potential plays a crucial role in determining the thermopower spectrum. For a tunable Rashba coupling, the thermopower of the junction can be controlled with precision, which may useful for the thermoelectric applications, at low temperatures. Further the efficiency of the system is obtained for different pairing correlations of the superconducting lead where we find that the system with a d-wave symmetry is more efficient as compared to a s-wave correlation, in some selective regions of effective barrier potential. It is found that for some selective regions of effective barrier potential, the efficiency of the system increases with RSOC and the opposite happens for other values.

Factors predicting barriers to exercise in midlife Australian women.

PubMed

McGuire, Amanda; Seib, Charrlotte; Anderson, Debra

2016-05-01

Chronic diseases are the leading cause of death and disability worldwide. They are, though, largely attributable to modifiable lifestyle risk factors, including lack of exercise. This study aims to investigate what factors predict perceptions of barriers to exercise in midlife women. This cross-sectional descriptive study collected data from midlife Australian women by online questionnaire. Volunteers aged between 40 and 65 years were recruited following media publicity about the study. The primary outcome measure was perceived exercise barriers (EBBS Barriers sub-scale). Other self-report data included: exercise, smoking, alcohol, fruit and vegetable consumption, body mass index, physical and mental health and well-being (MOS SF-12v2) and exercise self-efficacy. On average, the 225 participants were aged 50.9 years (SD=5.9). The significant predictors of perceived barriers to exercise were perceived benefits of exercise, exercise self-efficacy, physical well-being and mental well-being. These variables explained 41% of the variance in the final model (F (8219)=20.1, p<.01) CONCLUSIONS: In midlife women, perceptions of barriers to exercise correlate with beliefs about the health benefits of exercise, exercise self-efficacy, physical and mental well-being. These findings have application to health promotion interventions targeting exercise behaviour change in midlife women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Barriers and Facilitators to Exercise Participation in People with Hip and/or Knee Osteoarthritis: Synthesis of the Literature Using Behavior Change Theory.

PubMed

Dobson, Fiona; Bennell, Kim L; French, Simon D; Nicolson, Philippa J A; Klaasman, Remco N; Holden, Melanie A; Atkins, Lou; Hinman, Rana S

2016-05-01

Exercise is recommended for hip and knee osteoarthritis (OA). Patient initiation of, and adherence to, exercise is key to the success of managing symptoms. This study aimed to (1) identify modifiable barriers and facilitators to participation in intentional exercise in hip and/or knee OA, and (2) synthesize findings using behavior change theory. A scoping review with systematic searches was conducted through March 2015. Two reviewers screened studies for eligibility. Barriers and facilitators were extracted and synthesized according to the Theoretical Domains Framework (TDF) by two independent reviewers. Twenty-three studies (total of 4633 participants) were included. The greatest number of unique barriers and facilitators mapped to the Environmental Context and Resources domain. Many barriers were related to Beliefs about Consequences and Beliefs about Capabilities, whereas many facilitators were related to Reinforcement. Clinicians should take a proactive role in facilitating exercise uptake and adherence, rather than trusting patients to independently overcome barriers to exercise. Strategies that may be useful include a personalized approach to exercise prescription, considering environmental context and available resources, personalized education about beneficial consequences of exercise and reassurance about exercise capability, and use of reinforcement strategies. Future research should investigate the effectiveness of behavior change interventions that specifically target these factors.

Modeling the dynamics of a phreatic eruption based on a tilt observation: Barrier breakage leading to the 2014 eruption of Mount Ontake, Japan

NASA Astrophysics Data System (ADS)

Maeda, Yuta; Kato, Aitaro; Yamanaka, Yoshiko

2017-02-01

Although phreatic eruptions are common volcanic phenomena that sometimes result in significant disasters, their dynamics are poorly understood. In this study, we address the dynamics of the phreatic eruption of Mount Ontake, Japan, in 2014 based on analyses of a tilt change observed immediately (450 s) before the eruption onset. We conducted two sets of analysis: a waveform inversion and a modified phase-space analysis. Our waveform inversion of the tilt signal points to a vertical tensile crack at a depth of 1100 m. Our modified phase-space analysis suggests that the tilt change was at first a linear function in time that then switched to exponential growth. We constructed simple analytical models to explain these temporal functions. The linear function was explained by the boiling of underground water controlled by a constant heat supply from a greater depth. The exponential function was explained by the decompression-induced boiling of water and the upward Darcy flow of the water vapor through a permeable region of small cracks that were newly created in response to ongoing boiling. We interpret that this region was intact prior to the start of the tilt change, and thus, it has acted as a permeability barrier for the upward migration of fluids; it was a breakage of this barrier that led to the eruption.

Recruitment and training for home hemodialysis: experience and lessons from the Nocturnal Dialysis Trial.

PubMed

Pipkin, Mary; Eggers, Paul W; Larive, Brett; Rocco, Michael V; Stokes, John B; Suri, Rita S; Lockridge, Robert S

2010-09-01

We assessed perceived barriers and incentives to home hemodialysis and evaluated potential correlates with the duration of home hemodialysis training. Surveys were sent to the principal investigator and study coordinator for each clinical center in the Frequent Hemodialysis Network Nocturnal Trial. Baseline data were obtained on medical comorbidities, cognitive and physical functioning, sessions required for home hemodialysis training, and costs of home renovations. The most commonly perceived barriers included lack of patient motivation, unwillingness to change from in-center modality, and fear of self-cannulation. The most common incentives were greater scheduling flexibility and reduced travel time. The median costs for home renovations varied between $1191 and $4018. The mean number of home hemodialysis training sessions was 27.7 +/- 10.4 (11-59 days). Average training time was less for patients with experience in either self-care or both self-care and cannulation. The number of training sessions was unrelated to the score on the Modified Mini Mental Status or Trailmaking B tests or patient's education level. Training time also did not correlate with the SF-36 Physical Function subscale but did with the modified Charlson comorbidity score and older patient age. Lack of patient or family motivation and fear of the dialysis process are surmountable barriers for accepting home hemodialysis as a modality for renal replacement therapy. Formal education and scores on cognitive function tests are not predictors of training time.

The Employers' Perspective on Barriers and Facilitators to Employment of People with Intellectual Disability: A Differential Mixed-Method Approach

ERIC Educational Resources Information Center

Kocman, Andreas; Fischer, Linda; Weber, Germain

2018-01-01

Background: Obtaining employment is among the most important ambitions of people with intellectual disability. Progress towards comprehensive inclusive employment is hampered by numerous barriers. Limited research is available on these barriers and strategies to overcome them. Method: A mixed method approach in a sample of 30 HR-managers was used…

Barriers Keep Drops Of Water Out Of Infrared Gas Sensors

NASA Technical Reports Server (NTRS)

Murray, Sean K.

1996-01-01

Infrared-sensor cells used for measuring partial pressures of CO(2) and other breathable gases modified to prevent entry of liquid water into sensory optical paths of cells. Hydrophobic membrane prevents drops of water entrained in flow from entering optical path from lamp to infrared detectors.

Modifying lignin to improve bioenergy feedstocks: strengthening the barrier against pathogens?

USDA-ARS?s Scientific Manuscript database

Lignin is a ubiquitous polymer present in cell walls of all vascular plants, where it rigidifies and strengthens the cell wall structure through covalent cross-linkages to cell wall polysaccharides. The presence of lignin makes the cell wall recalcitrant to conversion into fermentable sugars for bi...

Financial Literacy Curriculum: The Effect on Offender Money Management Skills

ERIC Educational Resources Information Center

Koenig, Lori A.

2007-01-01

Offenders involved in this study lacked basic financial knowledge which presented a barrier to their success upon release. The researcher modified existing curriculum and created a course in financial literacy for offenders within a medium security correctional facility based upon their personal experiences. The offenders gained financial…

Modifying Dialectical Behavior Therapy for Deaf Individuals

ERIC Educational Resources Information Center

O'Hearn, Amanda; Pollard, Robert Q., Jr.

2008-01-01

Therapies that rely on written materials, information, or procedures involving familiarity with the dominant culture (e.g., colloquialisms, history) often pose barriers to people who use another language, have low English literacy, or are less familiar with the dominant culture. All this applies deaf individuals. One of the most well-validated…

Modifying the Existing Campus Building for Accessibility: Accessible Products Catalog.

ERIC Educational Resources Information Center

Cotler, Stephen Richard

This catalog is intended to assist architects and college administrators to select products that help physically handicapped people lead lives free of architectural barriers. The product information, obtained directly from the manufacturers, is listed on comparative matrix sheets, that can be used to achieve the design recommendations. Products of…

Unique Educational Needs of Learners with Physical and Other Health Impairments.

ERIC Educational Resources Information Center

Kendall, Robbie M.

This monograph addresses the educational needs of learners who have physical and health impairments that adversely interfere with their educational performance and who thus require special training, related services, adaptive equipment, modified materials, and/or barrier free facilities. The first section discusses the identification of learners…

46 CFR 56.07-5 - Definitions (modifies 100.2).

Code of Federal Regulations, 2010 CFR

2010-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND... similar fittings which form part of the pressure barrier of any system are included under this heading.... “Nonstandard fitting” means a component of a piping system which is not fabricated under an adopted industry...

Engineering species-like barriers to sexual reproduction.

PubMed

Maselko, Maciej; Heinsch, Stephen C; Chacón, Jeremy M; Harcombe, William R; Smanski, Michael J

2017-10-12

Controlling the exchange of genetic information between sexually reproducing populations has applications in agriculture, eradication of disease vectors, control of invasive species, and the safe study of emerging biotechnology applications. Here we introduce an approach to engineer a genetic barrier to sexual reproduction between otherwise compatible populations. Programmable transcription factors drive lethal gene expression in hybrid offspring following undesired mating events. As a proof of concept, we target the ACT1 promoter of the model organism Saccharomyces cerevisiae using a dCas9-based transcriptional activator. Lethal overexpression of actin results from mating this engineered strain with a strain containing the wild-type ACT1 promoter.Genetic isolation of a genetically modified organism represents a useful strategy for biocontainment. Here the authors use dCas9-VP64-driven gene expression to construct a 'species-like' barrier to reproduction between two otherwise compatible populations.

Temperature dependence of electrical characteristics of Pt/GaN Schottky diode fabricated by UHV e-beam evaporation.

PubMed

Kumar, Ashish; Arafin, Shamsul; Amann, Markus Christian; Singh, Rajendra

2013-11-15

Temperature-dependent electrical characterization of Pt/n-GaN Schottky barrier diodes prepared by ultra high vacuum evaporation has been done. Analysis has been made to determine the origin of the anomalous temperature dependence of the Schottky barrier height, the ideality factor, and the Richardson constant calculated from the I-V-T characteristics. Variable-temperature Hall effect measurements have been carried out to understand charge transport at low temperature. The modified activation energy plot from the barrier inhomogeneity model has given the value of 32.2 A/(cm2 K2) for the Richardson constant A** in the temperature range 200 to 380 K which is close to the known value of 26.4A/(cm2 K2) for n-type GaN.

Modulators of IgG penetration through the blood-brain barrier: Implications for Alzheimer's disease immunotherapy.

PubMed

Finke, John M; Banks, William A

2017-01-01

This review serves to highlight approaches that may improve the access of antibody drugs to regions of the brain affected by Alzheimer's Disease. While previous antibody drugs have been unsuccessful in treating Alzheimer's disease, recent work demonstrates that Alzheimer's pathology can be modified if these drugs can penetrate the brain parenchyma with greater efficacy. Research in antibody blood-brain barrier drug delivery predominantly follows one of three distinct directions: (1) enhancing influx with reduced antibody size, addition of Trojan horse modules, or blood-brain barrier disruption; (2) modulating trancytotic equilibrium and/or kinetics of the neonatal Fc Receptor; and (3) manipulation of antibody glycan carbohydrate composition. In addition to these topics, recent studies are discussed that reveal a role of glycan sialic acid in suppressing antibody efflux from the brain.

Transferability study of CHO cell clustering assays for monitoring of pertussis toxin activity in acellular pertussis vaccines.

PubMed

Isbrucker, R; Daas, A; Wagner, L; Costanzo, A

2016-01-01

Current regulations for acellular pertussis (aP) vaccines require that they are tested for the presence of residual or reversion-derived pertussis toxin (PTx) activity using the mouse histamine sensitisation test (HIST). Although a CHO cell clustering assay can be used by manufacturers to verify if sufficient inactivation of the substance has occurred in-process, this assay cannot be used at present for the final product due to the presence of aluminium adjuvants which interfere with mammalian cell cultures. Recently, 2 modified CHO cell clustering assays which accommodate for the adjuvant effects have been proposed as alternatives to the HIST. These modified assays eliminate the adjuvant-induced cytotoxicity either through dilution of the vaccine (called the Direct Method) or by introducing a porous barrier between the adjuvant and the cells (the Indirect Method). Transferability and suitability of these methods for testing of products present on the European market were investigated during a collaborative study organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). Thirteen laboratories participated in this study which included 4 aP-containing vaccines spiked by addition of PTx. This study also assessed the transferability of a standardised CHO cell clustering assay protocol for use with non-adjuvanted PTx preparations. Results showed that the majority of laboratories were able to detect the PTx spike in all 4 vaccines at concentrations of 4 IU/mL or lower using the Indirect Method. This sensitivity is in the range of the theoretical sensitivity of the HIST. The Direct Method however did not show the expected results and would need additional development work.

Effect of irradiation, active and modified atmosphere packaging, container oxygen barrier and storage conditions on the physicochemical and sensory properties of raw unpeeled almond kernels (Prunus dulcis).

PubMed

Mexis, Stamatios F; Riganakos, Kyriakos A; Kontominas, Michael G

2011-03-15

The present study investigated the effect of irradiation, active and modified atmosphere packaging, and storage conditions on quality retention of raw, whole, unpeeled almonds. Almond kernels were packaged in barrier and high-barrier pouches, under N(2) or with an O(2) absorber and stored either under fluorescent lighting or in the dark at 20 °C for 12 months. Quality parameters monitored were peroxide value, hexanal content, colour, fatty acid composition and volatile compounds. Of the sensory attributes colour, texture, odour and taste were evaluated. Peroxide value and hexanal increased with dose of irradiation and storage time. Irradiation resulted in a decrease of polyunsaturated and monounsaturated fatty acids during storage with a parallel increase of saturated fatty acids. Volatile compounds were not affected by irradiation but increased with storage time indicating enhanced lipid oxidation. Colour parameters of samples remained unaffected immediately after irradiation. For samples packaged under a N(2) , atmosphere L and b values decreased during storage with a parallel increase of value a resulting to gradual product darkening especially in irradiated samples. Non-irradiated almonds retained acceptable quality for ca. 12 months stored at 20 °C with the O(2) absorber irrespective of lighting conditions and packaging material oxygen barrier. The respective shelf life for samples irradiated at 1.0 kGy was 12 months packaged in PET-SiOx//LDPE irrespective of lighting conditions and 12 months for samples irradiated at 3 kGy packaged in PET-SiOx//LDPE stored in the dark. Copyright © 2010 Society of Chemical Industry.

In situ retreival of contaminants or other substances using a barrier system and leaching solutions and components, processes and methods relating thereto

DOEpatents

Nickelson, Reva A.; Walsh, Stephanie; Richardson, John G.; Dick, John R.; Sloan, Paul A.

2005-06-28

Processes and methods relating to treating contaminants and collecting desired substances from a zone of interest using subterranean collection and containment barriers. Tubular casings having interlock structures are used to create subterranean barriers for containing and treating buried waste and its effluents. The subterranean barrier includes an effluent collection system. Treatment solutions provided to the zone of interest pass therethrough and are collected by the barrier and treated or recovered, allowing on-site remediation. Barrier components may be used to in the treatment by collecting or removing contaminants or other materials from the zone of interest.

Method of in situ retrieval of contaminants or other substances using a barrier system and leaching solutions

DOEpatents

Nickelson, Reva A.; Walsh, Stephanie; Richardson, John G.; Dick, John R.; Sloan, Paul A.

2006-12-26

Processes and methods relating to treating contaminants and collecting desired substances from a zone of interest using subterranean collection and containment barriers. Tubular casings having interlock structures are used to create subterranean barriers for containing and treating buried waste and its effluents. The subterranean barrier includes an effluent collection system. Treatment solutions provided to the zone of interest pass therethrough and are collected by the barrier and treated or recovered, allowing on-site remediation. Barrier components may be used to in the treatment by collecting or removing contaminants or other materials from the zone of interest.

Efficient free energy calculations by combining two complementary tempering sampling methods.

PubMed

Xie, Liangxu; Shen, Lin; Chen, Zhe-Ning; Yang, Mingjun

2017-01-14

Although energy barriers can be efficiently crossed in the reaction coordinate (RC) guided sampling, this type of method suffers from identification of the correct RCs or requirements of high dimensionality of the defined RCs for a given system. If only the approximate RCs with significant barriers are used in the simulations, hidden energy barriers with small to medium height would exist in other degrees of freedom (DOFs) relevant to the target process and consequently cause the problem of insufficient sampling. To address the sampling in this so-called hidden barrier situation, here we propose an effective approach to combine temperature accelerated molecular dynamics (TAMD), an efficient RC-guided sampling method, with the integrated tempering sampling (ITS), a generalized ensemble sampling method. In this combined ITS-TAMD method, the sampling along the major RCs with high energy barriers is guided by TAMD and the sampling of the rest of the DOFs with lower but not negligible barriers is enhanced by ITS. The performance of ITS-TAMD to three systems in the processes with hidden barriers has been examined. In comparison to the standalone TAMD or ITS approach, the present hybrid method shows three main improvements. (1) Sampling efficiency can be improved at least five times even if in the presence of hidden energy barriers. (2) The canonical distribution can be more accurately recovered, from which the thermodynamic properties along other collective variables can be computed correctly. (3) The robustness of the selection of major RCs suggests that the dimensionality of necessary RCs can be reduced. Our work shows more potential applications of the ITS-TAMD method as the efficient and powerful tool for the investigation of a broad range of interesting cases.

Efficient free energy calculations by combining two complementary tempering sampling methods

NASA Astrophysics Data System (ADS)

Xie, Liangxu; Shen, Lin; Chen, Zhe-Ning; Yang, Mingjun

2017-01-01

Although energy barriers can be efficiently crossed in the reaction coordinate (RC) guided sampling, this type of method suffers from identification of the correct RCs or requirements of high dimensionality of the defined RCs for a given system. If only the approximate RCs with significant barriers are used in the simulations, hidden energy barriers with small to medium height would exist in other degrees of freedom (DOFs) relevant to the target process and consequently cause the problem of insufficient sampling. To address the sampling in this so-called hidden barrier situation, here we propose an effective approach to combine temperature accelerated molecular dynamics (TAMD), an efficient RC-guided sampling method, with the integrated tempering sampling (ITS), a generalized ensemble sampling method. In this combined ITS-TAMD method, the sampling along the major RCs with high energy barriers is guided by TAMD and the sampling of the rest of the DOFs with lower but not negligible barriers is enhanced by ITS. The performance of ITS-TAMD to three systems in the processes with hidden barriers has been examined. In comparison to the standalone TAMD or ITS approach, the present hybrid method shows three main improvements. (1) Sampling efficiency can be improved at least five times even if in the presence of hidden energy barriers. (2) The canonical distribution can be more accurately recovered, from which the thermodynamic properties along other collective variables can be computed correctly. (3) The robustness of the selection of major RCs suggests that the dimensionality of necessary RCs can be reduced. Our work shows more potential applications of the ITS-TAMD method as the efficient and powerful tool for the investigation of a broad range of interesting cases.

Vision-based calibration of parallax barrier displays

NASA Astrophysics Data System (ADS)

Ranieri, Nicola; Gross, Markus

2014-03-01

Static and dynamic parallax barrier displays became very popular over the past years. Especially for single viewer applications like tablets, phones and other hand-held devices, parallax barriers provide a convenient solution to render stereoscopic content. In our work we present a computer vision based calibration approach to relate image layer and barrier layer of parallax barrier displays with unknown display geometry for static or dynamic viewer positions using homographies. We provide the math and methods to compose the required homographies on the fly and present a way to compute the barrier without the need of any iteration. Our GPU implementation is stable and general and can be used to reduce latency and increase refresh rate of existing and upcoming barrier methods.

Barriers to GPs' use of evidence-based medicine: a systematic review

PubMed Central

Zwolsman, Sandra; te Pas, Ellen; Hooft, Lotty; Waard, Margreet Wieringa-de; van Dijk, Nynke

2012-01-01

Background GPs report various barriers to the use and practice of evidence-based medicine (EBM). A review of research on these barriers may help solve problems regarding the uptake of evidence in clinical outpatient practice. Aim To determine the barriers encountered by GPs in the practice of EBM and to come up with solutions to the barriers identified. Design A systematic review of the literature. Method The following databases were searched: MEDLINE® (PubMed®), Embase, CINAHL®, ERIC, and the Cochrane Library, until February 2011. Primary studies (all methods, all languages) that explore the barriers that GPs encounter in the practice of EBM were included. Results A total of 14 700 articles were identified, of which 22 fulfilled all inclusion criteria. Of the latter, nine concerned qualitative, 12 concerned quantitative, and one concerned both qualitative and quantitative research methods. The barriers described in the articles cover the categories: evidence (including the accompanying EBM steps), the GP’s preferences (experience, expertise, education), and the patient’s preferences. The particular GP setting also has important barriers to the use of EBM. Barriers found in this review, among others, include lack of time, EBM skills, and available evidence; patient-related factors; and the attitude of the GP. Conclusion Various barriers are encountered when using EBM in GP practice. Interventions that help GPs to overcome these barriers are needed, both within EBM education and in clinical practice. PMID:22781999

Moving evidence-based drug abuse prevention programs from basic science to practice: "bridging the efficacy-effectiveness interface".

PubMed

August, Gerald J; Winters, Ken C; Realmuto, George M; Tarter, Ralph; Perry, Cheryl; Hektner, Joel M

2004-01-01

This article examines the challenges faced by developers of youth drug abuse prevention programs in transporting scientifically proven or evidence-based programs into natural community practice systems. Models for research on the transfer of prevention technology are described with specific emphasis given to the relationship between efficacy and effectiveness studies. Barriers that impede the successful integration of efficacy methods within effectiveness studies (e.g., client factors, practitioner factors, intervention structure characteristics, and environmental and organizational factors) are discussed. We present a modified model for program development and evaluation that includes a new type of research design, the hybrid efficacy-effectiveness study that addresses program transportability. The utility of the hybrid study is illustrated in the evaluation of the Early Risers "Skills for Success" prevention program.

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

Zhu, Jinlong; Wang, Yonggang; Li, Shuai

Na-rich antiperovskites are recently developed solid electrolytes with enhanced sodium ionic conductivity and show promising functionality as a novel solid electrolyte in an all solid-state battery. In this work, the sodium ionic transport pathways of the parent compound Na3OBr, as well as the modified layered antiperovskite Na4OI2, were studied and compared through temperature dependent neutron diffraction combined with the maximum entropy method. In the cubic Na3OBr antiperovskite, the nuclear density distribution maps at 500 K indicate that sodium ions hop within and among oxygen octahedra, and Br- ions are not involved. In the tetragonal Na4OI2 antiperovskite, Na ions, which connectmore » octahedra in the ab plane, have the lowest activation energy barrier. The transport of sodium ions along the c axis is assisted by I- ions.« less

Adaptive management in the context of barriers in European freshwater ecosystems.

PubMed

Birnie-Gauvin, Kim; Tummers, Jeroen S; Lucas, Martyn C; Aarestrup, Kim

2017-12-15

Many natural habitats have been modified to accommodate for the presence of humans and their needs. Infrastructures - such as hydroelectric dams, weirs, culverts and bridges - are now a common occurrence in streams and rivers across the world. As a result, freshwater ecosystems have been altered extensively, affecting both biological and geomorphological components of the habitats. Many fish species rely on these freshwater ecosystems to complete their lifecycles, and the presence of barriers has been shown to reduce their ability to migrate and sustain healthy populations. In the long run, barriers may have severe repercussions on population densities and dynamics of aquatic animal species. There is currently an urgent need to address these issues with adequate conservation approaches. Adaptive management provides a relevant approach to managing barriers in freshwater ecosystems as it addresses the uncertainties of dealing with natural systems, and accommodates for future unexpected events, though this approach may not be suitable in all instances. A literature search on this subject yielded virtually no output. Hence, we propose a step-by-step guide for implementing adaptive management, which could be used to manage freshwater barriers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Involvement of specific macrophage-lineage cells surrounding arterioles in barrier and scavenger function in brain cortex.

PubMed Central

Mato, M; Ookawara, S; Sakamoto, A; Aikawa, E; Ogawa, T; Mitsuhashi, U; Masuzawa, T; Suzuki, H; Honda, M; Yazaki, Y; Watanabe, E; Luoma, J; Yla-Herttuala, S; Fraser, I; Gordon, S; Kodama, T

1996-01-01

The transport of solutes between blood and brain is regulated by a specific barrier. Capillary endothelial cells of brain are known to mediate barrier function and facilitate transport. Here we report that specific cells surrounding arterioles, known as Mato's fluorescent granular perithelial (FGP) cells or perivascular microglial cells, contribute to the barrier function. Immunohistochemical and in situ hybridization studies indicate that, in normal brain cortex, type I and type II macrophage scavenger receptors are expressed only in FGP/perivascular microglial cells, and surface markers of macrophage lineage are also detected on them. These cells mediate the uptake of macromolecules, including modified low density lipoprotein, horseradish peroxidase, and ferritin injected either into the blood or into the cerebral ventricles. Accumulation of scavenged materials with aging or after the administration of a high-fat diet results in the formation of honeycomb-like foam cells and the narrowing of the lumen of arterioles in the brain cortex. These results indicate involvement of FGP/perivascular microglial cells in the barrier and scavenger functions in the central nervous system. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:8622926

Method of making dense, conformal, ultra-thin cap layers for nanoporous low-k ILD by plasma assisted atomic layer deposition

DOEpatents

Jiang, Ying-Bing [Albuquerque, NM; Cecchi, Joseph L [Albuquerque, NM; Brinker, C Jeffrey [Albuquerque, NM

2011-05-24

Barrier layers and methods for forming barrier layers on a porous layer are provided. The methods can include chemically adsorbing a plurality of first molecules on a surface of the porous layer in a chamber and forming a first layer of the first molecules on the surface of the porous layer. A plasma can then be used to react a plurality of second molecules with the first layer of first molecules to form a first layer of a barrier layer. The barrier layers can seal the pores of the porous material, function as a diffusion barrier, be conformal, and/or have a negligible impact on the overall ILD k value of the porous material.

Where to Restore Ecological Connectivity? Detecting Barriers and Quantifying Restoration Benefits

PubMed Central

McRae, Brad H.; Hall, Sonia A.; Beier, Paul; Theobald, David M.

2012-01-01

Landscape connectivity is crucial for many ecological processes, including dispersal, gene flow, demographic rescue, and movement in response to climate change. As a result, governmental and non-governmental organizations are focusing efforts to map and conserve areas that facilitate movement to maintain population connectivity and promote climate adaptation. In contrast, little focus has been placed on identifying barriers—landscape features which impede movement between ecologically important areas—where restoration could most improve connectivity. Yet knowing where barriers most strongly reduce connectivity can complement traditional analyses aimed at mapping best movement routes. We introduce a novel method to detect important barriers and provide example applications. Our method uses GIS neighborhood analyses in conjunction with effective distance analyses to detect barriers that, if removed, would significantly improve connectivity. Applicable in least-cost, circuit-theoretic, and simulation modeling frameworks, the method detects both complete (impermeable) barriers and those that impede but do not completely block movement. Barrier mapping complements corridor mapping by broadening the range of connectivity conservation alternatives available to practitioners. The method can help practitioners move beyond maintaining currently important areas to restoring and enhancing connectivity through active barrier removal. It can inform decisions on trade-offs between restoration and protection; for example, purchasing an intact corridor may be substantially more costly than restoring a barrier that blocks an alternative corridor. And it extends the concept of centrality to barriers, highlighting areas that most diminish connectivity across broad networks. Identifying which modeled barriers have the greatest impact can also help prioritize error checking of land cover data and collection of field data to improve connectivity maps. Barrier detection provides a different way to view the landscape, broadening thinking about connectivity and fragmentation while increasing conservation options. PMID:23300719

Legal barriers in accessing opioid medicines: results of the ATOME quick scan of national legislation of eastern European countries.

PubMed

Vranken, Marjolein J M; Mantel-Teeuwisse, Aukje K; Jünger, Saskia; Radbruch, Lukas; Lisman, John; Scholten, Willem; Payne, Sheila; Lynch, Tom; Schutjens, Marie-Hélène D B

2014-12-01

Overregulation of controlled medicines is one of the factors contributing to limited access to opioid medicines. The purpose of this study was to identify legal barriers to access to opioid medicines in 12 Eastern European countries participating in the Access to Opioid Medication in Europa project, using a quick scan method. A quick scan method to identify legal barriers was developed focusing on eight different categories of barriers. Key experts in 12 European countries were requested to send relevant legislation. Legislation was quick scanned using World Health Organization guidelines. Overly restrictive provisions and provisions that contain stigmatizing language and incorrect definitions were identified. The selected provisions were scored into two categories: 1) barrier and 2) uncertain, and reviewed by two authors. A barrier was recorded if both authors agreed the selected provision to be a barrier (Category 1). National legislation was obtained from 11 of 12 countries. All 11 countries showed legal barriers in the areas of prescribing (most frequently observed barrier). Ten countries showed barriers in the areas of dispensing and showed stigmatizing language and incorrect use of definitions in their legislation. Most barriers were identified in the legislation of Bulgaria, Greece, Lithuania, Serbia, and Slovenia. The Cypriot legislation showed the fewest total number of barriers. The selected countries have in common as main barriers prescribing and dispensing restrictions, the use of stigmatizing language, and incorrect use of definitions. The practical impact of these barriers identified using a quick scan method needs to be validated by other means. Copyright © 2014 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

NASA Technical Reports Server (NTRS)

De, B. R.; Srnka, L. J.

1978-01-01

Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

A Pilot Study Promoting Participation of Families with Limited Resources in Early Autism Intervention

PubMed Central

Carr, Themba; Lord, Catherine

2016-01-01

Background Relatively little research about autism early intervention has occurred in families of low socioeconomic status. Barriers to participation for under-resourced families (i.e., families with low incomes or limited education), pose a significant problem. The purpose of this pilot study was to apply empirically supported methods promoting participation of families with low-income and low-education levels to an established intervention for children with autism spectrum disorder (ASD). Method Participant recruitment specifically targeted families whose income was equal to or below two times the federal poverty line and whose caregiver(s) had no more than two years of college attendance. An evidence-based intervention was modified to be more accessible to participating families. Adaptations focused on decreasing access barriers, decreasing attrition, and promoting positive change within families. Success of the program was measured quantitatively and qualitatively. Results Twenty-seven families were referred to the project, 13 of which did not meet eligibility requirements. Eight families enrolled, maintained participation for the majority of the project and provided positive qualitative feedback of their experiences. Project and treatment attrition were calculated at 62% and 12.5%, respectively. Treatment attendance was high, but length of time to complete treatment was greatly influenced by the number of session cancellations. Conclusions The exploratory project demonstrated that practical modifications to standard early intervention protocols can promote engagement in families with limited resources. Recommendations for programs seeking to implement interventions in under-resourced communities are discussed. PMID:27019670

Devices for overcoming biological barriers: the use of physical forces to disrupt the barriers.

PubMed

Mitragotri, Samir

2013-01-01

Overcoming biological barriers including skin, mucosal membranes, blood brain barrier as well as cell and nuclear membrane constitutes a key hurdle in the field of drug delivery. While these barriers serve the natural protective function in the body, they limit delivery of drugs into the body. A variety of methods have been developed to overcome these barriers including formulations, targeting peptides and device-based technologies. This review focuses on the use of physical methods including acoustic devices, electric devices, high-pressure devices, microneedles and optical devices for disrupting various barriers in the body including skin and other membranes. A summary of the working principles of these devices and their ability to enhance drug delivery is presented. Copyright © 2012. Published by Elsevier B.V.

Direct control and characterization of a Schottky barrier by scanning tunneling microscopy

NASA Technical Reports Server (NTRS)

Bell, L. D.; Kaiser, W. J.; Hecht, M. H.; Grunthaner, F. J.

1988-01-01

Scanning tunneling microscopy (STM) methods are used to directly control the barrier height of a metal tunnel tip-semiconductor tunnel junction. Barrier behavior is measured by tunnel current-voltage spectroscopy and compared to theory. A unique surface preparation method is used to prepare a low surface state density Si surface. Control of band bending with this method enables STM investigation of semiconductor subsurface properties.

Transport of Zn(OH)4(-2) ions across a polyolefin microporous membrane

NASA Astrophysics Data System (ADS)

Krejci, Ivan; Vanysek, Peter; Trojanek, Antonin

1993-04-01

Transport of ZN(OH)4(2-) ions through modified microporous polypropylene membranes (Celgard 3401, 350140) was studied using polarography and conductometry. Soluble Nafion as an ion exchange modifying agent was applied to the membrane by several techniques. The influence of Nafion and a surfactant on transport of zinc ions through the membrane was studied. A relationship between membrane impedance and the rate of Zn(OH)4(2-) transport was found. The found correlation between conductivity, ion permeability and Nafion coverage suggests a suitable technique of membrane preparation to obtain desired zinc ion barrier properties.

Barrier height inhomogeneity in electrical transport characteristics of InGaN/GaN heterostructure interfaces

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

Roul, Basanta; Central Research Laboratory, Bharat Electronics, Bangalore 560013; Mukundan, Shruti

2015-03-15

We have grown InGaN/GaN heterostructures using plasma-assisted molecular beam epitaxy and studied the temperature dependent electrical transport characteristics. The barrier height (φ{sub b}) and the ideally factor (η) estimated using thermionic emission model were found to be temperature dependent. The conventional Richardson plot of ln(J{sub s}/T{sup 2}) versus 1/kT showed two temperature regions (region-I: 400–500 K and region-II: 200–350 K) and it provides Richardson constants (A{sup ∗}) which are much lower than the theoretical value of GaN. The observed variation in the barrier height and the presence of two temperature regions were attributed to spatial barrier inhomogeneities at the heterojunctionmore » interface and was explained by assuming a double Gaussian distribution of barrier heights with mean barrier height values 1.61 and 1.21 eV with standard deviation (σ{sub s}{sup 2}) of 0.044 and 0.022 V, respectively. The modified Richardson plot of ln(J{sub s}/T{sup 2}) − (q{sup 2}σ{sub s}{sup 2}/2k{sup 2}T{sup 2}) versus 1/kT for two temperature regions gave mean barrier height values as 1.61 eV and 1.22 eV with Richardson constants (A{sup ∗}) values 25.5 Acm{sup −2}K{sup −2} and 43.9 Acm{sup −2}K{sup −2}, respectively, which are very close to the theoretical value. The observed barrier height inhomogeneities were interpreted on the basis of the existence of a double Gaussian distribution of barrier heights at the interface.« less

Barriers to Beta-Blocker Use and Up-Titration Among Patients with Heart Failure with Reduced Ejection Fraction.

PubMed

Levitan, Emily B; Van Dyke, Melissa K; Loop, Matthew Shane; O'Beirne, Ronan; Safford, Monika M

2017-12-01

For patients with heart failure with reduced ejection fraction (HFrEF), guidelines recommend use of beta-blockers with gradual up-titration. However, many patients with HFrEF do not use beta-blockers and up-titration is rare. Our purpose was to identify and rank barriers to beta-blocker use and up-titration from the perspective of primary care physicians. We conducted 4 moderated, structured group discussions among 19 primary care physicians using the nominal group technique; 16 participants also completed a survey. Participants generated lists of barriers to beta-blocker use and up-titration among patients with HFrEF. Each participant had six votes with three votes assigned to the item ranked most important, two to the second most important item, and one to the third most important item. Investigators characterized items into themes. The percentage of available votes was calculated for each theme. Fifteen of 16 participating primary care physicians who completed the survey reported that management of beta-blockers was their responsibility. Treatment/side effects, particularly hypotension, were identified as the most important barrier for beta-blocker use (72% of available votes) followed by polypharmacy (11%), healthcare system barriers (10%), and comorbidities (6%). Barriers to up-titration included treatment/side effects (49% of available votes), patient communication/buy-in (21%), polypharmacy (13%), and healthcare system barriers (8%). Many barriers to guideline concordant use of beta-blockers among patients with HFrEF identified by primary care providers are not readily modifiable. Addressing these barriers may require development, testing, and dissemination of protocols for beta-blocker initiation and up-titration that are safe and appropriate in primary care.

Effect of Hydrothermal Treatment on the Physicochemical, Rheological, and Oil-Resistant Properties of Rice Flour

USDA-ARS?s Scientific Manuscript database

Rice flour was thermo-mechanically modified by steam jet-cooking and the physico-chemical and rheological properties of the resulting product were characterized. Then, its performance in frying batters was evaluated as an oil barrier. Compared to native rice flour, the steam jet-cooked rice flour ...

Moisture sorption properties of composite boards from esterified aspen fiber

Treesearch

C. Clemons; R. A. Young; R. M. Rowell

1992-01-01

One barrier to producing wood-plastic composites with wood fiber is the poor thermoplasticity of wood fiber. The objective of our study was to determine the plasticization of chemically modified wood fiber through tests on unmodified and esterified fiberboards. Attrition-milled aspen fiber was esterified with neat acetic, maleic, or succinic anhydride. Fourier...

FROM NEEDS ASSESSMENT TO PARTICIPATORY RESEARCH: A COMMUNITY VISION OF HEALTH PROMOTION PROGRAMS IN ONE NATIVE AMERICAN COMMUNITY

USDA-ARS?s Scientific Manuscript database

OBJECTIVE: Identify unique cultural needs, priorities, program delivery preferences and barriers to achieving a healthy diet and lifestyle in one Native American community. DESIGN: A novel modified nominal group technique (NGT) conducted in four districts and three age groups (Elders, adults and...

Perspectives of Mexican-Origin Smokers on Healthy Eating and Physical Activity

ERIC Educational Resources Information Center

Strong, Larkin L.; Hoover, Diana S.; Heredia, Natalia I.; Krasny, Sarah; Spears, Claire A.; Correa-Fernández, Virmarie; Wetter, David W.; Fernandez, Maria E.

2016-01-01

Key modifiable risk behaviors such as smoking, poor diet and physical inactivity often cluster and may have multiplicative adverse effects on health. This study investigated barriers and facilitators to healthy eating and physical activity (PA) in overweight Mexican-origin smokers to inform the adaptation of an evidence-based smoking cessation…

Preparation of chitosan-based multifunctional nanocarriers overcoming multiple barriers for oral delivery of insulin.

PubMed

Li, Lei; Jiang, Guohua; Yu, Weijiang; Liu, Depeng; Chen, Hua; Liu, Yongkun; Tong, Zaizai; Kong, Xiangdong; Yao, Juming

2017-01-01

To overcome multiple barriers for oral delivery of insulin, the chitosan-based multifunctional nanocarriers modified by L-valine (LV, used as a target ligand to facilitate the absorption of the small intestine) and phenylboronic acid (PBA, used as a glucose-responsive unit) have been designed and evaluated in this study. The resultant nanocarriers exhibited low cytotoxicity against HT-29 cells and excellent stability against protein solution. The insulin release behaviors were evaluated triggered by pH and glucose in vitro. The chemical stability of loaded insulin against digestive enzyme were established in presence of simulated gastric fluid (SGF) containing pepsin and simulated intestinal fluid (SIF) containing pancreatin, respectively. The uptake behavior of HT-29 cells was evaluated by confocal laser scanning microscope. After oral administration to the diabetic rats, an effective hypoglycemic effect was obtained compared with subcutaneous injection of insulin. This work suggests that L-valine modified chitosan-based multifunctional nanocarriers may be a promising drug delivery carrier for oral administration of insulin. Copyright © 2016 Elsevier B.V. All rights reserved.

Blend-modification of soy protein/lauric acid edible films using polysaccharides.

PubMed

Pan, Hongyang; Jiang, Bo; Chen, Jie; Jin, Zhengyu

2014-05-15

Different types of polysaccharides (propyleneglycol alginate (PGA), pectin, carrageenan and aloe polysaccharide) were incorporated into soy protein isolate (SPI)/lauric acid (La) films using a co-drying process or by direct addition to form biodegradable composite films with modified water vapour permeability (WVP) and mechanical properties. The WVP of SPI/La/polysaccharide films decreased when polysaccharides were added using the co-drying process, regardless of the type of polysaccharide. The tensile strength of SPI/La film was increased by the addition of polysaccharides, and the percentage elongation at break was increased by incorporating PGA using the co-drying process. Regarding oxygen-barrier performance, no notable differences were observed between the SPI/La and SPI/La/polysaccharide films. The most significant improvement was observed by blending PGA, with the co-dried preparation exhibiting better properties than the direct-addition preparation. Scanning electron microscopy (SEM) revealed that the microstructures of the films are the basis for the differences in the barrier and mechanical properties of the modified blends of SPI, polysaccharides and La. Copyright © 2013 Elsevier Ltd. All rights reserved.

The myth of natural barriers. Is transgene introgression by genetically modified crops an environmental risk?

PubMed

Guarnieri, Vincenzo; Benessia, Alice; Camino, Elena; Barbiero, Giuseppe

2008-01-01

Genetically modified (GM) crops under open field conditions are a complex and controversial issue. Ecologists are discussing about the possibility that a transgene belonging to GM plants could spread to native populations through a process known as introgression the stable incorporation of a gene in the host genome able to generate a differentiated population. The ecological consequences of a transgene introgression in plants or bacteria are not yet well understood, but could be significant. In this critical review we consider vertical and horizontal introgression. We analyse the biochemical and genetic constraints, and environmental factors that limit the possibility of transgene spread; meanwhile we show cases in which the natural barriers are overcome. Then we discuss the overall management of GM crops, noting the shortcomings and approximations of risk assessment based on linear thinking typical of the biomolecular approach. Finally we suggest to explicitly weight facts together with values and we encourage the undertaking of an ecological perspective, encompassing the complexity of (non-linear) relations between organisms and the environment.

Cardiovascular and Antiobesity Effects of Resveratrol Mediated through the Gut Microbiota.

PubMed

Bird, Julia K; Raederstorff, Daniel; Weber, Peter; Steinert, Robert E

2017-11-01

Encouraging scientific research into the health effects of dietary bioactive resveratrol has been confounded by its rapid first-pass metabolism, which leads to low in vivo bioavailability. Preliminary studies have shown that resveratrol can modulate gut microbiota composition, undergo biotransformation to active metabolites via the intestinal microbiota, or affect gut barrier function. In rodents, resveratrol can modify the relative Bacteroidetes:Firmicutes ratio and reverse the gut microbial dysbiosis caused by a high-fat diet. By upregulating the expression of genes involved in maintaining tight junctions between intestinal cells, resveratrol contributes to gut barrier integrity. The composition of the gut microbiome and rapid metabolism of resveratrol determines the production of resveratrol metabolites, which are found at greater concentrations in humans after ingestion than their parent molecule and can have similar biological effects. Resveratrol may affect cardiovascular risk factors such as elevated blood cholesterol or trimethylamine N -oxide concentrations. Modulating the composition of the gut microbiota by resveratrol may affect central energy metabolism and modify concentrations of satiety hormones to produce antiobesity effects. Encouraging research from animal models could be tested in humans. © 2017 American Society for Nutrition.

Characterization of the inhomogeneous barrier distribution in a Pt/(100)β-Ga2O3 Schottky diode via its temperature-dependent electrical properties

NASA Astrophysics Data System (ADS)

Jian, Guangzhong; He, Qiming; Mu, Wenxiang; Fu, Bo; Dong, Hang; Qin, Yuan; Zhang, Ying; Xue, Huiwen; Long, Shibing; Jia, Zhitai; Lv, Hangbing; Liu, Qi; Tao, Xutang; Liu, Ming

2018-01-01

β-Ga2O3 is an ultra-wide bandgap semiconductor with applications in power electronic devices. Revealing the transport characteristics of β-Ga2O3 devices at various temperatures is important for improving device performance and reliability. In this study, we fabricated a Pt/β-Ga2O3 Schottky barrier diode with good performance characteristics, such as a low ON-resistance, high forward current, and a large rectification ratio. Its temperature-dependent current-voltage and capacitance-voltage characteristics were measured at various temperatures. The characteristic diode parameters were derived using thermionic emission theory. The ideality factor n was found to decrease from 2.57 to 1.16 while the zero-bias barrier height Φb0 increased from 0.47 V to 1.00 V when the temperature was increased from 125 K to 350 K. This was explained by the Gaussian distribution of barrier height inhomogeneity. The mean barrier height Φ ¯ b0 = 1.27 V and zero-bias standard deviation σ0 = 0.13 V were obtained. A modified Richardson plot gave a Richardson constant A* of 36.02 A.cm-2.K-2, which is close to the theoretical value of 41.11 A.cm-2.K-2. The differences between the barrier heights determined using the capacitance-voltage and current-voltage curves were also in line with the Gaussian distribution of barrier height inhomogeneity.

Self-efficacy toward physical activity and the physical activity behavior of children with and without Developmental Coordination Disorder.

PubMed

Batey, C A; Missiuna, C A; Timmons, B W; Hay, J A; Faught, B E; Cairney, J

2014-08-01

Affecting 5-6% of children, Developmental Coordination Disorder (DCD) is a prevalent chronic condition. The nature of the disorder - impaired motor coordination - makes avoidance of physical activity (PA) common. The purpose of this study was to examine the effect of barrier and task self-efficacy on PA behavior in children with DCD and a group of typically developing (TD) children. Children were compared on their perceived ability to complete different intensities and duration of PA (task efficacy) and their confidence in completing PA when faced with everyday barriers (barrier efficacy). An accelerometer was used to record their activity over the subsequent week. Children with DCD were found to have significantly lower task efficacy and barrier efficacy. They also spent significantly less time in moderate to vigorous physical activity (MVPA). Multivariate analyses revealed that gender modified the relationship for both groups. Separate multivariate regressions, were therefore conducted by gender. A direct effect of DCD on PA was observed for boys, but not for girls. Further analyses showed that neither task efficacy nor barrier efficacy influenced the relationship between DCD and PA. Results from this study confirm that children with DCD have lower task and barrier self-efficacy than TD children and that males have lower PA levels than their TD peers; however neither task or barrier self-efficacy mediated the relationship between DCD and PA. Copyright © 2013. Published by Elsevier B.V.

Perceived Barriers and Facilitators to School Social Work Practice: A Mixed-Methods Study

ERIC Educational Resources Information Center

Teasley, Martell; Canifield, James P.; Archuleta, Adrian J.; Crutchfield, Jandel; Chavis, Annie McCullough

2012-01-01

Understanding barriers to practice is a growing area within school social work research. Using a convenience sample of 284 school social workers, this study replicates the efforts of a mixed-method investigation designed to identify barriers and facilitators to school social work practice within different geographic locations. Time constraints and…

A reaction-diffusion model of the Darien Gap Sterile Insect Release Method

NASA Astrophysics Data System (ADS)

Alford, John G.

2015-05-01

The Sterile Insect Release Method (SIRM) is used as a biological control for invasive insect species. SIRM involves introducing large quantities of sterilized male insects into a wild population of invading insects. A fertile/sterile mating produces offspring that are not viable and the wild insect population will eventually be eradicated. A U.S. government program maintains a permanent sterile fly barrier zone in the Darien Gap between Panama and Columbia to control the screwworm fly (Cochliomyia Hominivorax), an insect that feeds off of living tissue in mammals and has devastating effects on livestock. This barrier zone is maintained by regular releases of massive quantities of sterilized male screwworm flies from aircraft. We analyze a reaction-diffusion model of the Darien Gap barrier zone. Simulations of the model equations yield two types of spatially inhomogeneous steady-state solutions representing a sterile fly barrier that does not prevent invasion and a barrier that does prevent invasion. We investigate steady-state solutions using both phase plane methods and monotone iteration methods and describe how barrier width and the sterile fly release rate affects steady-state behavior.

Use of microalgae to remove pollutants from power plant discharges

DOEpatents

Wilde, Edward W.; Benemann, John R.; Weissman, Joseph C.; Tillett, David M.

1991-01-01

A method and system for removing pollutants dissolved in the aqueous discharge of a plant, such as a power plant, from a body of water having known hydraulogy and physicochemical characteristics, the method comprising (a) modifying the hydraulic system of the body of water including use of physical barriers to define a zone in a portion of the body of water which zone includes the discharge point and where the water has a range of physicochemical characteristics; (b) selecting a large and preferably filamentous, planktonically growing strain of algae adapted to absorb the particular pollutants and genetically dominating algae at the physicochemical characteristics of the zone; (c) establishing a colony of the selected algal strain in the zone; (d) harvesting a portion of the colony; and (e) reinnoculating the zone near the discharge point with a fraction of the harvested portion. The fraction used for reinnoculation can be adjusted to balance the rate of pollutant removal to the rate of pollutant discharge.

Use of microalgae to remove pollutants from power plant discharges

DOEpatents

Wilde, E.W.; Benemann, J.R.; Weissman, J.C.; Tillett, D.M.

1991-04-30

A method and system are described for removing pollutants dissolved in the aqueous discharge of a plant, such as a power plant, from a body of water having known hydraulic and physicochemical characteristics, the method comprising (a) modifying the hydraulic system of the body of water including use of physical barriers to define a zone in a portion of the body of water which zone includes the discharge point and where the water has a range of physicochemical characteristics; (b) selecting a large and preferably filamentous, planktonically growing strain of algae adapted to absorb the particular pollutants and genetically dominating algae at the physicochemical characteristics of the zone; (c) establishing a colony of the selected algal strain in the zone; (d) harvesting a portion of the colony; and (e) reinoculating the zone near the discharge point with a fraction of the harvested portion. The fraction used for reinoculation can be adjusted to balance the rate of pollutant removal to the rate of pollutant discharge. 4 figures.

Bacterial and fungal biofilm formation on anodized titanium alloys with fluorine.

PubMed

Perez-Jorge, Concepcion; Arenas, Maria-Angeles; Conde, Ana; Hernández-Lopez, Juan-Manuel; de Damborenea, Juan-Jose; Fisher, Steve; Hunt, Alessandra M Agostinho; Esteban, Jaime; James, Garth

2017-01-01

Orthopaedic device-related infections are closely linked to biofilm formation on the surfaces of these devices. Several modified titanium (Ti-6Al-4V) surfaces doped with fluorine were studied in order to evaluate the influence of these modifications on biofilm formation by Gram-positive and Gram-negative bacteria as well as a yeast. The biofilm studies were performed according to the standard test method approved by ASTM (Designation: E2196-12) using the Rotating Disk Reactor. Four types of Ti-6Al-4V samples were tested; chemically polished (CP), two types of nanostructures containing fluorine, nanoporous (NP) and nanotubular (NT), and non-nanostructured fluorine containing samples (fluoride barrier layers, FBL). Different species of Gram-positive cocci, (Staphylococcus aureus and epidermidis), Gram-negative rods (Escherichia coli, Pseudomonas aeruginosa), and a yeast (Candida albicans) were studied. For one of the Gram-positive (S. epidermidis) and one of the Gram-negative (E. coli) species a statistically-significant decrease in biofilm accumulation for NP and NT samples was found when compared with the biofilm accumulation on CP samples. The results suggest an effect of the modified materials on the biofilm formation.

Composition and method for removing photoresist materials from electronic components

DOEpatents

Davenhall, Leisa B.; Rubin, James B.

2002-01-01

The invention is a combination of at least one dense phase fluid and at least one dense phase fluid modifier which can be used to contact substrates for electronic parts such as semiconductor wafers or chips to remove photoresist materials which are applied to the substrates during manufacture of the electronic parts. The dense phase fluid modifier is one selected from the group of cyclic, aliphatic or alicyclic compounds having the functional group: ##STR1## wherein Y is a carbon, oxygen, nitrogen, phosphorus or sulfur atom or a hydrocarbon group having from 1 to 10 carbon atoms, a halogen or halogenated hydrocarbon group having from 1 to 10 carbon atoms, silicon or a fluorinated silicon group; and wherein R.sub.1 and R.sub.2 can be the same or different substituents; and wherein, as in the case where X is nitrogen, R.sub.1 or R.sub.2 may not be present. The invention compositions generally are applied to the substrates in a pulsed fashion in order to remove the hard baked photoresist material remaining on the surface of the substrate after removal of soft baked photoresist material and etching of the barrier layer.

Ion Implantation-Modified Fluorine-Doped Tin Oxide by Zirconium with Continuously Tunable Work Function and Its Application in Perovskite Solar Cells.

PubMed

Han, Dong; Wu, Cuncun; Zhao, Yunbiao; Chen, Yi; Xiao, Lixin; Zhao, Ziqiang

2017-12-06

In recent years, perovskite solar cells have drawn a widespread attention. As an electrode material, fluorine-doped tin oxide (FTO) is widely used in various kinds of solar cells. However, the relatively low work function (WF) (∼4.6 eV) limits its application. The potential barrier between the transparent conductive oxide electrode and the hole transport layer (HTL) in inverted perovskite solar cells results in a decrease in device performance. In this paper, we propose a method to adjust WF of FTO by implanting zirconium ions into the FTO surface. The WF of FTO can be precisely and continuously tuned between 4.59 and 5.55 eV through different dopant concentration of zirconium. In the meantime, the modified FTO, which had a WF of 5.1 eV to match well the highest occupied molecular orbital energy level of poly(3,4-ethylenedioxylenethiophene):polystyrene sulfonate, was used as the HTL in inverted planar perovskite solar cells. Compared with the pristine FTO electrode-based device, the open circuit voltage increased from 0.82 to 0.91 V, and the power conversion efficiency increased from 11.6 to 14.0%.

Developing theory-informed behaviour change interventions to implement evidence into practice: a systematic approach using the Theoretical Domains Framework.

PubMed

French, Simon D; Green, Sally E; O'Connor, Denise A; McKenzie, Joanne E; Francis, Jill J; Michie, Susan; Buchbinder, Rachelle; Schattner, Peter; Spike, Neil; Grimshaw, Jeremy M

2012-04-24

There is little systematic operational guidance about how best to develop complex interventions to reduce the gap between practice and evidence. This article is one in a Series of articles documenting the development and use of the Theoretical Domains Framework (TDF) to advance the science of implementation research. The intervention was developed considering three main components: theory, evidence, and practical issues. We used a four-step approach, consisting of guiding questions, to direct the choice of the most appropriate components of an implementation intervention: Who needs to do what, differently? Using a theoretical framework, which barriers and enablers need to be addressed? Which intervention components (behaviour change techniques and mode(s) of delivery) could overcome the modifiable barriers and enhance the enablers? And how can behaviour change be measured and understood? A complex implementation intervention was designed that aimed to improve acute low back pain management in primary care. We used the TDF to identify the barriers and enablers to the uptake of evidence into practice and to guide the choice of intervention components. These components were then combined into a cohesive intervention. The intervention was delivered via two facilitated interactive small group workshops. We also produced a DVD to distribute to all participants in the intervention group. We chose outcome measures in order to assess the mediating mechanisms of behaviour change. We have illustrated a four-step systematic method for developing an intervention designed to change clinical practice based on a theoretical framework. The method of development provides a systematic framework that could be used by others developing complex implementation interventions. While this framework should be iteratively adjusted and refined to suit other contexts and settings, we believe that the four-step process should be maintained as the primary framework to guide researchers through a comprehensive intervention development process.

Barriers to, and facilitators of, the prevention of unintentional injury in children in the home: a systematic review and synthesis of qualitative research.

PubMed

Smithson, Janet; Garside, Ruth; Pearson, Mark

2011-04-01

This review considers barriers to, and facilitators of, success for interventions to reduce unintentional injury to children in the home through supply and/or installation of home safety equipment, and looks at risk assessments. A systematic review of qualitative research. Bibliographic databases were searched for studies on interventions to reduce unintentional child injury in the home, or on related attitudes and behaviours. Studies were quality appraised, findings extracted, and a conceptual framework was developed to assess factors affecting the success of interventions. Nine peer-reviewed journal articles were included. Barriers and facilitators were highlighted at organisational, environmental and personal levels. Effective provision of safety equipment involves ongoing support with installation and maintenance. Take up and success of interventions depends on adjusting interventions according to practical limitations and parents' cultural expectations. A particular barrier was parents' inability to modify rented or shared accommodation. The review highlights ways in which health inequalities affect the take up and success of home safety interventions, and how health workers can use this knowledge to facilitate future interventions.

Awareness, Facilitators, and Barriers to Policy Implementation Related to Obesity Prevention for Primary School Children in Malaysia.

PubMed

Chan, Camelina; Moy, Foong Ming; Lim, Jennifer N W; Dahlui, Maznah

2018-03-01

To assess the awareness, facilitators, and barriers to policy implementation related to obesity prevention for primary school children. A cross-sectional study administered using an online questionnaire. Conducted in 447 primary schools in a state in Malaysia. One school administrator from each school served as a participant. The questionnaires consisted of 32 items on awareness, policy implementation, and facilitators and barriers to policy implementation. Descriptive analysis was used to describe the awareness, facilitators, and barriers of policies implementation. Association between schools' characteristics and policy implementation was assessed using logistic regression. The majority (90%) of school administrators were aware of the policies. However, only 50% to 70% of schools had implemented the policies fully. Reported barriers were lack of equipment, insufficient training, and limited time to complete implementation. Facilitators of policy implementation were commitment from the schools, staff members, students, and canteen operators. Policy implementation was comparable in all school types and locality; except the policy on "Food and Drinks sold at the school canteens" was implemented by more rural schools compared to urban schools (odds ratio: 1.74, 95% confidence interval: 1.13-2.69). Majority of the school administrators were aware of the existing policies; however, the implementation was only satisfactory. The identified barriers to policy implementation were modifiable and thus, the stakeholders should consider restrategizing plans in overcoming them.

Effect of nanodimensional polyethylenimine layer on surface potential barriers of hybrid structures based on silicon single crystal

NASA Astrophysics Data System (ADS)

Malyar, Ivan V.; Gorin, Dmitry A.; Stetsyura, Svetlana V.

2013-01-01

In this report we present the analysis of I-V curves for MIS-structures like silicon substrate / nanodimensional polyelectrolyte layer / metal probe (contact) which is promising for biosensors, microfluidic chips, different devices of molecular electronics, such as OLEDs, solar cells, where polyelectrolyte layers can be used to modify semiconductor surface. The research is directed to investigate the contact phenomena which influence the resulting signal of devices mentioned above. The comparison of I-V characteristics of such structures measured by scanning tunnel microscopy (contactless technique) and using contact areas deposited by thermal evaporation onto the organic layer (the contact one) was carried out. The photoassisted I-V measurements and complex analysis based on Simmons and Schottky models allow one to extract the potential barriers and to observe the changes of charge transport in MIS-structures under illumination and after polyelectrolyte adsorption. The direct correlation between the thickness of the deposited polyelectrolyte layer and both equilibrium tunnel barrier and Schottky barrier height was observed for hybrid structures with polyethylenimine. The possibility of control over the I-V curves of hybrid structure and the height of the potential barriers (for different charge transports) by illumination was confirmed. Based on experimental data and complex analysis the band diagrams were plotted which illustrate the changes of potential barriers for MIS-structures due to the polyelectrolyte adsorption and under the illumination.

Structuring unbreakable hydrophobic barriers in paper

NASA Astrophysics Data System (ADS)

Nargang, Tobias M.; Kotz, Frederik; Rapp, Bastian E.

2018-02-01

Hydrophobic barriers are one of the key elements of microfluidic paper based analytical devices (μPADs).μPADs are simple and cost efficient and they can be carried out without the need of high standard laboratories. To carry out such a test a method is needed to create stable hydrophobic barriers. Commonly used methods like printing wax or polystyrene have the major drawback that these barriers are stiff and break if bended which means they will no longer be able to retain a liquid sample. Here we present silanes to structure hydrophobic barriers via polycondensation and show a silanization method which combines the advantages of flexible silane/siloxane layers with the short processing times of UV-light based structuring. The barriers are created by using methoxy silanes which are mixed with a photo acid generator (PAG) as photoinitiator. Also a photosensitizer was given to the mixture to increase the effectiveness of the PAG. After the PAG is activated by UV-light the silane is hydrolyzed and coupled to the cellulose via polycondensation. The created hydrophobic barriers are highly stable and do not break if being bended.

Facilitating the Timely Discharge of Well Newborns by Using Quality Improvement Methods.

PubMed

Rochester, Nicole T; Banach, Laurie P; Hoffner, Wendy; Zeltser, Deena; Lewis, Phyllis; Seelbach, Elizabeth; Cuzzi, Sandra

2018-05-01

Discharges are a key driver of hospital throughput. Our pediatric hospitalist team sought to improve newborn nursery throughput by increasing the percentage of newborns on our service with a discharge order by 11 am. We hypothesized that implementing a discharge checklist would result in earlier discharge times for newborns who met discharge criteria. We identified barriers to timely discharge through focus groups with key stakeholders, chart reviews, and brainstorming sessions. We subsequently created and implemented a discharge checklist to identify and address barriers before daily rounds. We tracked mean monthly discharge order times. Finally, we performed chart reviews to determine causes for significantly delayed discharge orders and used this information to modify rounding practices during a second plan-do-study-act cycle. During the 2-year period before the intervention, 24% of 3224 newborns had a discharge order entered by 11 am. In the 20 months after the intervention, 39% of 2739 newborns had a discharge order by 11 am, a 63% increase compared with the baseline. Observation for group B Streptococcus exposure was the most frequent reason for a late discharge order. There are many factors that affect the timely discharge of well newborns. The development and implementation of a discharge checklist improved our ability to discharge newborns on our pediatric hospitalist service by 11 am. Future studies to identify nonphysician barriers to timely newborn discharges may lead to further improvements in throughput between the labor and delivery and maternity suites units. Copyright © 2018 by the American Academy of Pediatrics.

The need to promote behaviour change at the cultural level: one factor explaining the limited impact of the MEMA kwa Vijana adolescent sexual health intervention in rural Tanzania. A process evaluation

PubMed Central

2012-01-01

Background Few of the many behavioral sexual health interventions in Africa have been rigorously evaluated. Where biological outcomes have been measured, improvements have rarely been found. One of the most rigorous trials was of the multi-component MEMA kwa Vijana adolescent sexual health programme, which showed improvements in knowledge and reported attitudes and behaviour, but none in biological outcomes. This paper attempts to explain these outcomes by reviewing the process evaluation findings, particularly in terms of contextual factors. Methods A large-scale, primarily qualitative process evaluation based mainly on participant observation identified the principal contextual barriers and facilitators of behavioural change. Results The contextual barriers involved four interrelated socio-structural factors: culture (i.e. shared practices and systems of belief), economic circumstances, social status, and gender. At an individual level they appeared to operate through the constructs of the theories underlying MEMA kwa Vijana - Social Cognitive Theory and the Theory of Reasoned Action – but the intervention was unable to substantially modify these individual-level constructs, apart from knowledge. Conclusion The process evaluation suggests that one important reason for this failure is that the intervention did not operate sufficiently at a structural level, particularly in regard to culture. Recently most structural interventions have focused on gender or/and economics. Complementing these with a cultural approach could address the belief systems that justify and perpetuate gender and economic inequalities, as well as other barriers to behaviour change. PMID:22978613

Access to primary care for socio-economically disadvantaged older people in rural areas: A qualitative study

PubMed Central

Turley, Rachel; Porter, Tom; Shakespeare, Tom; Wong, Geoff; Jones, Andy P.; Steel, Nick

2018-01-01

Objective We aim to explore the barriers to accessing primary care for socio-economically disadvantaged older people in rural areas. Methods Using a community recruitment strategy, fifteen people over 65 years, living in a rural area, and receiving financial support were recruited for semi-structured interviews. Four focus groups were held with rural health professionals. Interviews and focus groups were audio-recorded and transcribed. Thematic analysis was used to identify barriers to primary care access. Findings Older people’s experience can be understood within the context of a patient perceived set of unwritten rules or social contract–an individual is careful not to bother the doctor in return for additional goodwill when they become unwell. However, most found it difficult to access primary care due to engaged telephone lines, availability of appointments, interactions with receptionists; breaching their perceived social contract. This left some feeling unwelcome, worthless or marginalised, especially those with high expectations of the social contract or limited resources, skills and/or desire to adapt to service changes. Health professionals’ described how rising demands and expectations coupled with service constraints had necessitated service development, such as fewer home visits, more telephone consultations, triaging calls and modifying the appointment system. Conclusion Multiple barriers to accessing primary care exist for this group. As primary care is re-organised to reduce costs, commissioners and practitioners must not lose sight of the perceived social contract and models of care that form the basis of how many older people interact with the service. PMID:29509811

Apical effect of diosmectite on damage to the intestinal barrier induced by basal tumour necrosis factor-alpha.

PubMed Central

Mahraoui, L; Heyman, M; Plique, O; Droy-Lefaix, M T; Desjeux, J F

1997-01-01

BACKGROUND: In many digestive diseases the intestinal barrier is weakened by the release of proinflammatory cytokines, including tumour necrosis factor-alpha (TNF alpha). AIM: To investigate the protective effect of apical diosmectite on the intestinal dysfunction induced by the proinflammatory cytokine TNF alpha. METHODS: Filter grown monolayers of the intestinal cell line HT29-19A were incubated for 48 hours in basal medium containing 10 ng/ml TNF alpha and 5 U/ml interferon-gamma (IFN gamma). Next, 1, 10, or 100 mg/ml diosmectite was placed in the apical medium for one hour. Intestinal function was then assessed in Ussing chambers by measuring ionic conductance (G) and apicobasal fluxes of 14C-mannitol (Jman), and intact horseradish peroxidase. In control intestinal monolayers, diosmectite did not significantly modify G, Jman, or intact horseradish peroxidase. RESULTS: After incubation with TNF alpha and IFN gamma, intestinal function altered, as shown by the increases compared with control values for G (22.8 (3.7) v (9.6 (0.5) mS/cm2), Jman (33.8 (7.5) v 7.56 (0.67) micrograms/h x cm2), and intact horseradish peroxidase (1.95 (1.12) v 0.14 (0.04) micrograms/h x cm2). G and Jman were closely correlated, suggesting that the increase in permeability was paracellular. Treatment with diosmectite restored al the variables to control values. CONCLUSIONS: Basal TNF alpha disrupts the intestinal barrier through the tight junctions, and apical diosmectite counteracts this disruption. PMID:9135522

Circularly polarized antennas for active holographic imaging through barriers

DOEpatents

McMakin, Douglas L [Richland, WA; Severtsen, Ronald H [Richland, WA; Lechelt, Wayne M [West Richland, WA; Prince, James M [Kennewick, WA

2011-07-26

Circularly-polarized antennas and their methods of use for active holographic imaging through barriers. The antennas are dielectrically loaded to optimally match the dielectric constant of the barrier through which images are to be produced. The dielectric loading helps to remove barrier-front surface reflections and to couple electromagnetic energy into the barrier.

Device and method for producing a containment barrier underneath and around in-situ buried waste

DOEpatents

Gardner, Bradley M.; Smith, Ann M.; Hanson, Richard W.; Hodges, Richard T.

1998-01-01

An apparatus for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably on which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground and injection means for inserting barrier-forming material into the void. In one embodiment, the digging means is a continuous cutting chain. Mounted on the continuous cutting chain are cutter teeth for cutting through soil and discharge paddles for removing the loosened soil. This invention includes a barrier placement machine, a method for building an underground horizontal containment barrier using the barrier placement machine, and the underground containment system. Preferably the underground containment barrier goes underneath and around the site to be contained in a bathtub-type containment.

Ion-barrier for memristors/ReRAM and methods thereof

DOEpatents

Haase, Gad S.

2017-11-28

The present invention relates to memristive devices including a resistance-switching element and a barrier element. In particular examples, the barrier element is a monolayer of a transition metal chalcogenide that sufficiently inhibits diffusion of oxygen atoms or ions out of the switching element. As the location of these atoms and ions determine the state of the device, inhibiting diffusion would provide enhanced state retention and device reliability. Other types of barrier elements, as well as methods for forming such elements, are described herein.

Flexible barrier film, method of forming same, and organic electronic device including same

DOEpatents

Blizzard, John; Tonge, James Steven; Weidner, William Kenneth

2013-03-26

A flexible barrier film has a thickness of from greater than zero to less than 5,000 nanometers and a water vapor transmission rate of no more than 1.times.10.sup.-2 g/m.sup.2/day at 22.degree. C. and 47% relative humidity. The flexible barrier film is formed from a composition, which comprises a multi-functional acrylate. The composition further comprises the reaction product of an alkoxy-functional organometallic compound and an alkoxy-functional organosilicon compound. A method of forming the flexible barrier film includes the steps of disposing the composition on a substrate and curing the composition to form the flexible barrier film. The flexible barrier film may be utilized in organic electronic devices.

Swedish nurses encounter barriers when promoting healthy habits in children.

PubMed

Ljungkrona-Falk, Lena; Brekke, Hilde; Nyholm, Maria

2014-12-01

To increase the understanding of difficulties in promoting healthy habits to parents, we explore barriers in health-care provision. The aim of this study is to describe nurses' perceived barriers when discussing with parents regarding healthy food habits, physical activity and their child's body weight. A mixed method approach was chosen. Nurses (n = 76) working at 29 different Child Health Care Centers' in an area in west Sweden were included in the study. Three focus group interviews were conducted and 17 nurses were selected according to maximum variation. Data were categorized and qualitative content analysis was the chosen analysis method. In the second method, data were obtained from a questionnaire distributed to all 76 nurses. The latent content was formulated into a theme: even with encouragement and support, the nurses perceive barriers of both an external and internal nature. The results identified four main barriers: experienced barriers in the workplace-internal and external; the nurse's own fear and uncertainty; perceived obstacles in nurse-parent interactions and modern society impedes parents' ability to promote healthy habits. The nurses' perceived barriers were confirmed by the results from 62 of the nurses who completed the questionnaire. Despite education and professional support, the health professionals perceived both external and internal barriers in promoting healthy habits to parents when implementing a new method of health promotion in primary care. Further qualitative studies are needed to gain deeper understanding of the perceived barriers when promoting healthy habits to parents. © The Author (2013). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

When ruthenia met titania: Achieving extraordinary catalytic activity at low temperature by nanostructuring of oxides

DOE PAGES

Graciani, J.; Stacchiola, D.; Yang, F.; ...

2015-09-09

Nanostructured RuO x/TiO 2(110) catalysts have a remarkable catalytic activity for CO oxidation at temperatures in the range of 350–375 K. Furthermore, the RuO 2(110) surface has no activity. The state-of-the-art DFT calculations indicate that the main reasons for such an impressive improvement in the catalytic activity are: (i) a decrease of the diffusion barrier of adsorbed O atoms by around 40%, from 1.07 eV in RuO 2(110) to 0.66 eV in RuO x/TiO 2(110), which explains the shift of the activity to lower temperatures and (ii) a lowering of the barrier by 20% for the association of adsorbed COmore » and O species to give CO 2 (the main barrier for the CO oxidation reaction) passing from around 0.7 eV in RuO 2(110) to 0.55 eV in RuO x/TiO 2(110). We show that the catalytic properties of ruthenia are strongly modified when supported as nanostructures on titania, attaining higher activity at temperatures 100 K lower than that needed for pure ruthenia. As in other systems consisting of ceria nanostructures supported on titania, nanostructured ruthenia shows strongly modified properties compared to the pure oxide, consolidating the fact that the nanostructuring of oxides is a main way to attain higher catalytic activity at lower temperatures.« less

Application of C/C composites to the combustion chamber of rocket engines. Part 1: Heating tests of C/C composites with high temperature combustion gases

NASA Astrophysics Data System (ADS)

Tadano, Makoto; Sato, Masahiro; Kuroda, Yukio; Kusaka, Kazuo; Ueda, Shuichi; Suemitsu, Takeshi; Hasegawa, Satoshi; Kude, Yukinori

1995-04-01

Carbon fiber reinforced carbon composite (C/C composite) has various superior properties, such as high specific strength, specific modulus, and fracture strength at high temperatures of more than 1800 K. Therefore, C/C composite is expected to be useful for many structural applications, such as combustion chambers of rocket engines and nose-cones of space-planes, but C/C composite lacks oxidation resistivity in high temperature environments. To meet the lifespan requirement for thermal barrier coatings, a ceramic coating has been employed in the hot-gas side wall. However, the main drawback to the use of C/C composite is the tendency for delamination to occur between the coating layer on the hot-gas side and the base materials on the cooling side during repeated thermal heating loads. To improve the thermal properties of the thermal barrier coating, five different types of 30-mm diameter C/C composite specimens constructed with functionally gradient materials (FGM's) and a modified matrix coating layer were fabricated. In this test, these specimens were exposed to the combustion gases of the rocket engine using nitrogen tetroxide (NTO) / monomethyl hydrazine (MMH) to evaluate the properties of thermal and erosive resistance on the thermal barrier coating after the heating test. It was observed that modified matrix and coating with FGM's are effective in improving the thermal properties of C/C composite.

Prevalence of Barriers and Facilitators to Enhancing Conservative Kidney Management for Older Adults in the Primary Care Setting.

PubMed

Tam-Tham, Helen; King-Shier, Kathryn M; Thomas, Chandra M; Quinn, Robert R; Fruetel, Karen; Davison, Sara N; Hemmelgarn, Brenda R

2016-11-07

Conservative management of adults with stage 5 CKD (eGFR<15 ml/min per 1.73 m 2 ) is increasingly being provided in the primary care setting. We aimed to examine perceived barriers and facilitators for conservative management of older adults by primary care physicians. In 2015, we conducted a cross-sectional, population-based survey of all primary care physicians in Alberta, Canada. Eligible participants had experience caring for adults ages ≥75 years old with stage 5 CKD not planning on initiating dialysis. Questionnaire items were on the basis of a qualitative descriptive study informed by the Behavior Change Wheel and tested for face and content validity. Physicians were contacted via postal mail and/or fax on the basis of a modified Dillman method. Four hundred nine eligible primary care physicians completed the questionnaire (9.6% response rate). The majority of respondents were men (61.6%), were ages 40-60 years old (62.6%), and practiced in a large/medium population center (68.0%). The most common barrier to providing conservative care in the primary care setting was the inability to access support to maintain patients in the home setting (39.1% of respondents; 95% confidence interval, 34.6% to 43.6%). The second most common barrier was working with nonphysician providers with limited kidney-specific clinical expertise (32.3%; 95% confidence interval, 28.0% to 36.7%). Primary care physicians indicated that the two most common strategies that would enhance their ability to provide conservative management would be the ability to use the telephone to contact a nephrologist or clinical staff from the conservative care clinic (86.9%; 95% confidence interval, 83.7% to 90.0% and 85.6%; 95% confidence interval, 82.4% to 88.9%, respectively). We identified important areas to inform clinical programs to reduce barriers and enhance facilitators to improve primary care physicians' provision of conservative kidney care. In particular, primary care physicians require additional resources for maintaining patients in their home and telephone access to nephrologists and conservative care specialists. Copyright © 2016 by the American Society of Nephrology.

Prevalence of Barriers and Facilitators to Enhancing Conservative Kidney Management for Older Adults in the Primary Care Setting

PubMed Central

Tam-Tham, Helen; King-Shier, Kathryn M.; Thomas, Chandra M.; Quinn, Robert R.; Fruetel, Karen; Davison, Sara N.

2016-01-01

Background and objectives Conservative management of adults with stage 5 CKD (eGFR<15 ml/min per 1.73 m2) is increasingly being provided in the primary care setting. We aimed to examine perceived barriers and facilitators for conservative management of older adults by primary care physicians. Design, setting, participants, & measurements In 2015, we conducted a cross–sectional, population–based survey of all primary care physicians in Alberta, Canada. Eligible participants had experience caring for adults ages ≥75 years old with stage 5 CKD not planning on initiating dialysis. Questionnaire items were on the basis of a qualitative descriptive study informed by the Behavior Change Wheel and tested for face and content validity. Physicians were contacted via postal mail and/or fax on the basis of a modified Dillman method. Results Four hundred nine eligible primary care physicians completed the questionnaire (9.6% response rate). The majority of respondents were men (61.6%), were ages 40–60 years old (62.6%), and practiced in a large/medium population center (68.0%). The most common barrier to providing conservative care in the primary care setting was the inability to access support to maintain patients in the home setting (39.1% of respondents; 95% confidence interval, 34.6% to 43.6%). The second most common barrier was working with nonphysician providers with limited kidney–specific clinical expertise (32.3%; 95% confidence interval, 28.0% to 36.7%). Primary care physicians indicated that the two most common strategies that would enhance their ability to provide conservative management would be the ability to use the telephone to contact a nephrologist or clinical staff from the conservative care clinic (86.9%; 95% confidence interval, 83.7% to 90.0% and 85.6%; 95% confidence interval, 82.4% to 88.9%, respectively). Conclusions We identified important areas to inform clinical programs to reduce barriers and enhance facilitators to improve primary care physicians’ provision of conservative kidney care. In particular, primary care physicians require additional resources for maintaining patients in their home and telephone access to nephrologists and conservative care specialists. PMID:27551007

Rat model of blood-brain barrier disruption to allow targeted neurovascular therapeutics.

PubMed

Martin, Jacob A; Maris, Alexander S; Ehtesham, Moneeb; Singer, Robert J

2012-11-30

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain barrier(1). The barrier selectively excludes molecules from crossing between the blood and the brain based upon their size and charge. This function can impede the delivery of therapeutics for neurological disorders. A number of chemotherapeutic drugs, for example, will not effectively cross the blood-brain barrier to reach tumor cells(2). Thus, improving the delivery of drugs across the blood-brain barrier is an area of interest. The most prevalent methods for enhancing the delivery of drugs to the brain are direct cerebral infusion and blood-brain barrier disruption(3). Direct intracerebral infusion guarantees that therapies reach the brain; however, this method has a limited ability to disperse the drug(4). Blood-brain barrier disruption (BBBD) allows drugs to flow directly from the circulatory system into the brain and thus more effectively reach dispersed tumor cells. Three methods of barrier disruption include osmotic barrier disruption, pharmacological barrier disruption, and focused ultrasound with microbubbles. Osmotic disruption, pioneered by Neuwelt, uses a hypertonic solution of 25% mannitol that dehydrates the cells of the blood-brain barrier causing them to shrink and disrupt their tight junctions. Barrier disruption can also be accomplished pharmacologically with vasoactive compounds such as histamine(5) and bradykinin(6). This method, however, is selective primarily for the brain-tumor barrier(7). Additionally, RMP-7, an analog of the peptide bradykinin, was found to be inferior when compared head-to-head with osmotic BBBD with 25% mannitol(8). Another method, focused ultrasound (FUS) in conjunction with microbubble ultrasound contrast agents, has also been shown to reversibly open the blood-brain barrier(9). In comparison to FUS, though, 25% mannitol has a longer history of safety in human patients that makes it a proven tool for translational research(10-12). In order to accomplish BBBD, mannitol must be delivered at a high rate directly into the brain's arterial circulation. In humans, an endovascular catheter is guided to the brain where rapid, direct flow can be accomplished. This protocol models human BBBD as closely as possible. Following a cut-down to the bifurcation of the common carotid artery, a catheter is inserted retrograde into the ECA and used to deliver mannitol directly into the internal carotid artery (ICA) circulation. Propofol and N2O anesthesia are used for their ability to maximize the effectiveness of barrier disruption(13). If executed properly, this procedure has the ability to safely, effectively, and reversibly open the blood-brain barrier and improve the delivery of drugs that do not ordinarily reach the brain (8,13,14).

Method and device for detecting impact events on a security barrier which includes a hollow rebar allowing insertion and removal of an optical fiber

DOEpatents

Pies, Ross E.

2016-03-29

A method and device for the detection of impact events on a security barrier. A hollow rebar is farmed within a security barrier, whereby the hollow rebar is completely surrounded by the security barrier. An optical fiber passes through the interior of the hollow rebar. An optical transmitter and an optical receiver are both optically connected to the optical fiber and connected to optical electronics. The optical electronics are configured to provide notification upon the detection of an impact event at the security barrier based on the detection of disturbances within the optical fiber.

Enablers and barriers to physical activity in overweight and obese pregnant women: an analysis informed by the theoretical domains framework and COM-B model.

PubMed

Flannery, C; McHugh, S; Anaba, A E; Clifford, E; O'Riordan, M; Kenny, L C; McAuliffe, F M; Kearney, P M; Byrne, M

2018-05-21

Obesity during pregnancy is associated with increased risk of gestational diabetes mellitus (GDM) and other complications. Physical activity is a modifiable lifestyle factor that may help to prevent these complications but many women reduce their physical activity levels during pregnancy. Interventions targeting physical activity in pregnancy are on-going but few identify the underlying behaviour change mechanisms by which the intervention is expected to work. To enhance intervention effectiveness, recent tools in behavioural science such as the Theoretical Domains Framework (TDF) and COM-B model (capability, opportunity, motivation and behaviour) have been employed to understand behaviours for intervention development. Using these behaviour change methods, this study aimed to identify the enablers and barriers to physical activity in overweight and obese pregnant women. Semi-structured interviews were conducted with a purposive sample of overweight and obese women at different stages of pregnancy attending a public antenatal clinic in a large academic maternity hospital in Cork, Ireland. Interviews were recorded and transcribed into NVivo V.10 software. Data analysis followed the framework approach, drawing on the TDF and the COM-B model. Twenty one themes were identified and these mapped directly on to the COM-B model of behaviour change and ten of the TDF domains. Having the social opportunity to engage in physical activity was identified as an enabler; pregnant women suggested being active was easier when supported by their partners. Knowledge was a commonly reported barrier with women lacking information on safe activities during pregnancy and describing the information received from their midwife as 'limited'. Having the physical capability and physical opportunity to carry out physical activity were also identified as barriers; experiencing pain, a lack of time, having other children, and working prevented women from being active. A wide range of barriers and enablers were identified which influenced women's capability, motivation and opportunity to engage in physical activity with "knowledge" as the most commonly reported barrier. This study is a theoretical starting point in making a 'behavioural diagnoses' and the results will be used to inform the development of an intervention to increase physical activity levels among overweight and obese pregnant women.

Factors involved in selecting the birth type among primiparous women

PubMed Central

Safari-Moradabadi, Ali; Alavi, Azin; Pormehr-Yabandeh, Asiyeh; Eftekhaari, Tasnim Eghbal; Dadipoor, Sakineh

2018-01-01

BACKGROUND: Mortality and disability rates were reported to be respectively 2-3 and 5-10 times higher in C-sections compared to Vaginal delivery. OBJECTIVES: This study was aimed to explore the factors involved in selecting the birth type among primiparous women. METHODS: The present cross-sectional research was conducted on 220 primiparous women, who visited the health-care centers of Bandar Abbas. They were recruited in their first trimester of pregnancy with a simple randomized clustering method. Data were collected in a researcher-designed questionnaire. Its validity was confirmed by a panel of experts and reliability was tested and approved through the test–retest method. Mean, standard deviation, independent sample t-test, and Chi-squared tests for data analysis were done by SPSS 16. P < 0.05 was considered statistically significant. RESULTS: The mean age of the participants was 27.40 ± 6.07 years. The main barriers to the choice of vaginal delivery were the fear of pain and fear of vaginal area tears and ruptures, fear of injury to fetus, and doctor's recommendation. A statistically significant correlation was observed between the age, education, employment, income, awareness, and the reasons for preferring surgical childbirth. CONCLUSIONS: To reduce the rate of unnecessary cesarean sections (C-section), the following recommendations are suggested: Reducing fear of pain in expectant mothers, modifying wrong beliefs about the culture of natural childbirth, increasing awareness of fewer adverse effects of vaginal delivery including the vaginal tears if the mother abides by all midwife(s) instructions during the delivery procedure, providing educational courses for the necessary movements during the delivery, decreasing surgeons’ payment for C-section, and increasing payment for natural childbirth and implementing barriers for optional delivery to reduce the C-section. PMID:29693036

Permeabilization of the blood-brain barrier via mucosal engrafting: implications for drug delivery to the brain.

PubMed

Bleier, Benjamin S; Kohman, Richie E; Feldman, Rachel E; Ramanlal, Shreshtha; Han, Xue

2013-01-01

Utilization of neuropharmaceuticals for central nervous system(CNS) disease is highly limited due to the blood-brain barrier(BBB) which restricts molecules larger than 500Da from reaching the CNS. The development of a reliable method to bypass the BBB would represent an enormous advance in neuropharmacology enabling the use of many potential disease modifying therapies. Previous attempts such as transcranial catheter implantation have proven to be temporary and associated with multiple complications. Here we describe a novel method of creating a semipermeable window in the BBB using purely autologous tissues to allow for high molecular weight(HMW) drug delivery to the CNS. This approach is inspired by recent advances in human endoscopic transnasal skull base surgical techniques and involves engrafting semipermeable nasal mucosa within a surgical defect in the BBB. The mucosal graft thereby creates a permanent transmucosal conduit for drugs to access the CNS. The main objective of this study was to develop a murine model of this technique and use it to evaluate transmucosal permeability for the purpose of direct drug delivery to the brain. Using this model we demonstrate that mucosal grafts allow for the transport of molecules up to 500 kDa directly to the brain in both a time and molecular weight dependent fashion. Markers up to 40 kDa were found within the striatum suggesting a potential role for this technique in the treatment of Parkinson's disease. This proof of principle study demonstrates that mucosal engrafting represents the first permanent and stable method of bypassing the BBB thereby providing a pathway for HMW therapeutics directly into the CNS.

Permeabilization of the Blood-Brain Barrier via Mucosal Engrafting: Implications for Drug Delivery to the Brain

PubMed Central

Bleier, Benjamin S.; Kohman, Richie E.; Feldman, Rachel E.; Ramanlal, Shreshtha; Han, Xue

2013-01-01

Utilization of neuropharmaceuticals for central nervous system(CNS) disease is highly limited due to the blood-brain barrier(BBB) which restricts molecules larger than 500Da from reaching the CNS. The development of a reliable method to bypass the BBB would represent an enormous advance in neuropharmacology enabling the use of many potential disease modifying therapies. Previous attempts such as transcranial catheter implantation have proven to be temporary and associated with multiple complications. Here we describe a novel method of creating a semipermeable window in the BBB using purely autologous tissues to allow for high molecular weight(HMW) drug delivery to the CNS. This approach is inspired by recent advances in human endoscopic transnasal skull base surgical techniques and involves engrafting semipermeable nasal mucosa within a surgical defect in the BBB. The mucosal graft thereby creates a permanent transmucosal conduit for drugs to access the CNS. The main objective of this study was to develop a murine model of this technique and use it to evaluate transmucosal permeability for the purpose of direct drug delivery to the brain. Using this model we demonstrate that mucosal grafts allow for the transport of molecules up to 500 kDa directly to the brain in both a time and molecular weight dependent fashion. Markers up to 40 kDa were found within the striatum suggesting a potential role for this technique in the treatment of Parkinson’s disease. This proof of principle study demonstrates that mucosal engrafting represents the first permanent and stable method of bypassing the BBB thereby providing a pathway for HMW therapeutics directly into the CNS. PMID:23637885

Facilitators and barriers to exercise adherence in patients with osteopenia and osteoporosis: a systematic review.

PubMed

Rodrigues, I B; Armstrong, J J; Adachi, J D; MacDermid, J C

2017-03-01

The aim of this study was to categorize the facilitators and barriers of exercise and identify methods to promote exercise adherence in the osteoporosis population. Despite the fair methodological quality of included randomized controlled trials (RCTs), less than 75 % identified facilitators and barriers to exercise. Methods to promote and measure exercise adherence were poorly reported. Several studies have shown exercise to be successful in maintaining or increasing BMD in individuals with low bone mass. Yet, adherence to exercise is poor, with 50 % of those registered in an exercise program dropping out within the first 6 months, lack of time being the number one barrier in many populations. However, in the osteoporosis population, the main facilitator and barrier to exercise is still unclear. The aim of this study is to examine the extent to which RCTs reported the facilitators and the barriers to exercise and identified methods to promote adherence to an exercise program. PubMed, CINHAL, EMBASE, and the Cochrane Review were queried using a predefined search criterion, and the resulting citations were imported into DistillerSR. Screening was carried out by two independent reviewers, and articles were included in the analysis by consensus. The methodological quality of included studies was assessed using the PEDro scale. Fifty-four RCTs examining exercise interventions in patients with osteopenia or osteoporosis were included. A spectrum of facilitators and barriers to exercise for osteoporotic patients were identified; however, no one facilitator was more frequently reported than the other. The most commonly reported barriers were lack of time and transportation. In most RCTs, methods to promote and measure exercise adherence were unsatisfactory. Of the 54 papers, 72 % reported an adherence rate to an exercise program; the lowest reported rate was 51.7 %, and the highest 100 %. Most RCTs found were of fair quality; however, less than three quarters identified facilitators and barriers to exercise. Reporting of methods to promote and measure exercise adherence were low. Future work should be directed toward identifying major facilitators and barriers to exercise adherence within RCTs. Only then can methods be identified to leverage facilitators and overcome barriers, thus strengthening the evidence for efficacy of optimal interventional exercise programs. This review has been registered in PROSPERO under registration number CRD42016039941.

Penetration through the Skin Barrier.

PubMed

Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

2016-01-01

The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates. During recent decades, the latter has received increased attention as a route for intentionally delivering drugs to patients. This has stimulated research in methods for sampling, measuring and predicting percutaneous penetration. Previous chapters have described how different endogenous, genetic and exogenous factors may affect barrier characteristics. The present chapter introduces the theory for barrier penetration (Fick's law), and describes and discusses different methods for measuring the kinetics of percutaneous penetration of chemicals, including in vitro methods (static and flow-through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous penetration. Finally, a short discussion of the advantages and challenges of each method is provided, which will hopefully allow the reader to improve decision making and treatment planning, as well as the evaluation of experimental studies of percutaneous penetration of chemicals. © 2016 S. Karger AG, Basel.

Room temperature current-voltage (I-V) characteristics of Ag/InGaN/n-Si Schottky barrier diode

NASA Astrophysics Data System (ADS)

Erdoğan, Erman; Kundakçı, Mutlu

2017-02-01

Metal-semiconductors (MSs) or Schottky barrier diodes (SBDs) have a significant potential in the integrated device technology. In the present paper, electrical characterization of Ag/InGaN/n-Si Schottky diode have been systematically carried out by simple Thermionic method (TE) and Norde function based on the I-V characteristics. Ag ohmic and schottky contacts are deposited on InGaN/n-Si film by thermal evaporation technique under a vacuum pressure of 1×10-5 mbar. Ideality factor, barrier height and series resistance values of this diode are determined from I-V curve. These parameters are calculated by TE and Norde methods and findings are given in a comparetive manner. The results show the consistency for both method and also good agreement with other results obtained in the literature. The value of ideality factor and barrier height have been determined to be 2.84 and 0.78 eV at room temperature using simple TE method. The value of barrier height obtained with Norde method is calculated as 0.79 eV.

Didactical Design Material Units of Distance and Speed to Developed Mathematical Connection in Elementary School

NASA Astrophysics Data System (ADS)

Jannah, R. R.; Apriliya, S.; Karlimah

2017-03-01

This study aims to develop alternative instructional design based of barriers learning which identified by developing mathematical connection capabilities to the material unit of distance and speed. The research was conducted in the fifth grade elementary school Instructional design is complemented with a hypothetical learning trajectory in the form of a pedagogical didactic anticipation. The method used is descriptive method with qualitative approach. Techniques data collection used were observation, interviews, and documentation. The instrument used the researchers themselves are equipped with an instrument written test. The data were analyzed qualitatively to determine the student learning obstacles, then arrange hypothetical learning trajectory and pedagogical didactic anticipation. Learning obstacle are identified, it is learning obstacle related the connections between mathematical topics, learning obstacle related with other disciplines, and learning obstacle related with everyday life. The results of this research are improvement and development of didactic design in mathematics which has activities mathematical connection to the material unit of distance and speed in elementary school. The learning activities are carried out is using varied methods include method lectures, demonstrations, practice and exercise, as well as using the modified instructional media.

Leveraging technology: creating and sustaining changes for health.

PubMed

Teyhen, Deydre S; Aldag, Matt; Edinborough, Elton; Ghannadian, Jason D; Haught, Andrea; Kinn, Julie; Kunkler, Kevin J; Levine, Betty; McClain, James; Neal, David; Stewart, Tiffany; Thorndike, Frances P; Trabosh, Valerie; Wesensten, Nancy; Parramore, David J

2014-09-01

The rapid growth and evolution of health-related technology capabilities are driving an established presence in the marketplace and are opening up tremendous potential to minimize and/or mitigate barriers associated with achieving optimal health, performance, and readiness. This article summarizes technology-based strategies that promote healthy habits related to physical activity, nutrition, and sleep. The Telemedicine and Advanced Technology Research Center convened a workshop titled "Leveraging Technology: Creating & Sustaining Changes for Health" (May 29-30, 2013, Fort Detrick, MD). Participants included experts from academia (n=3), government (n=33), and industry (n=16). A modified Delphi method was used to establish expert consensus in six topic areas: (1) physical activity, (2) nutrition, (3) sleep, (4) incentives for behavior change, (5) usability/interoperability, and (6) mobile health/open platform. Overall, 162 technology features, constructs, and best practices were reviewed and prioritized for physical activity monitors (n=29), nutrition monitors (n=35), sleep monitors (n=24), incentives for change (n=36), usability and interoperability (n=25), and open data (n=13). Leading practices, gaps, and research needs for technology-based strategies were identified and prioritized. This information can be used to provide a research and development road map for (1) leveraging technology to minimize barriers to enhancing health and (2) facilitating evidence-based techniques to create and sustain healthy behaviors.

Participation in Leisure Activity and Exercise of Chronic Stroke Survivors Using Community-Based Rehabilitation Services in Seongnam City

PubMed Central

Yi, Tae Im; Lee, Ko Eun; Ha, Seung A

2015-01-01

Objective To clarify how participation in leisure activities and exercise by chronic stroke survivors differs before and after a stroke. Methods Sixty chronic stroke survivors receiving community-based rehabilitation services from a health center in Seongnam City were recruited. They completed a questionnaire survey regarding their demographic characteristics and accompanying diseases, and on the status of their leisure activities and exercise. In addition, their level of function (Korean version of Modified Barthel Index score), risk of depression (Beck Depression Inventory), and quality of life (SF-8) were measured. Results After their stroke, most of the respondents had not returned to their pre-stroke levels of leisure activity participation. The reported number of leisure activities declined from a mean of 3.9 activities before stroke to 1.9 activities post-stroke. In addition, many participants became home-bound, sedentary, and non-social after their stroke. The most common barriers to participation in leisure activities were weakness and poor balance, lack of transportation, and cost. The respondents reported a mean daily time spent on exercise of 2.6±1.3 hours. Pain was the most common barrier to exercise participation. Conclusion Chronic stroke survivors need information on leisure activities and appropriate pain management. PMID:25932420

Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

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

Samolyuk, German D.; Osetskiy, Yury N.; Stoller, Roger E.

We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascademore » production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (~0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential.« less

Molecular dynamics modeling of atomic displacement cascades in 3C-SiC: Comparison of interatomic potentials

DOE PAGES

Samolyuk, German D.; Osetskiy, Yury N.; Stoller, Roger E.

2015-06-03

We used molecular dynamics modeling of atomic displacement cascades to characterize the nature of primary radiation damage in 3C-SiC. We demonstrated that the most commonly used interatomic potentials are inconsistent with ab initio calculations of defect energetics. Both the Tersoff potential used in this work and a modified embedded-atom method potential reveal a barrier to recombination of the carbon interstitial and carbon vacancy which is much higher than the density functional theory (DFT) results. The barrier obtained with a newer potential by Gao and Weber is closer to the DFT result. This difference results in significant differences in the cascademore » production of point defects. We have completed both 10 keV and 50 keV cascade simulations in 3C-SiC at a range of temperatures. In contrast to the Tersoff potential, the Gao-Weber potential produces almost twice as many C vacancies and interstitials at the time of maximum disorder (~0.2 ps) but only about 25% more stable defects at the end of the simulation. Only about 20% of the carbon defects produced with the Tersoff potential recombine during the in-cascade annealing phase, while about 60% recombine with the Gao-Weber potential.« less

Universal functions of nuclear proximity potential for Skyrme nucleus-nucleus interaction in a semiclassical approach

NASA Astrophysics Data System (ADS)

Gupta, Raj K.; Singh, Dalip; Kumar, Raj; Greiner, Walter

2009-07-01

The universal function of the nuclear proximity potential is obtained for the Skyrme nucleus-nucleus interaction in the semiclassical extended Thomas-Fermi (ETF) approach. This is obtained as a sum of the spin-orbit-density-independent and spin-orbit-density-dependent parts of the Hamiltonian density, since the two terms behave differently, the spin-orbit-density-independent part mainly attractive and the spin-orbit-density-dependent part mainly repulsive. The semiclassical expansions of kinetic energy density and spin-orbit density are allowed up to second order, and the two-parameter Fermi density, with its parameters fitted to experiments, is used for the nuclear density. The universal functions or the resulting nuclear proximity potential reproduce the 'exact' Skyrme nucleus-nucleus interaction potential in the semiclassical approach, within less than ~1 MeV of difference, both at the maximum attraction and in the surface region. An application of the resulting interaction potential to fusion excitation functions shows clearly that the parameterized universal functions of nuclear proximity potential substitute completely the 'exact' potential in the Skyrme energy density formalism based on the semiclassical ETF method, including also the modifications of interaction barriers at sub-barrier energies in terms of modifying the constants of the universal functions.

Psychiatric versus physical disabilities: A comparison of barriers and facilitators to employment.

PubMed

Sevak, Purvi; Khan, Shamima

2017-06-01

Guided by the social model of disability (Nagi, 1965), this study aims to better identify barriers to and facilitators of employment for individuals with psychiatric disabilities and how these factors may differ for individuals with physical disabilities. Our analysis uses data from the Survey of Disability and Employment on 2,148 individuals with psychiatric disabilities, physical disabilities, or both who in 2014 applied for services from 1 of 3 state vocational rehabilitation (VR) agencies. We identify type of disability based on respondents' open-ended descriptions of their impairments. We use univariate statistics and multivariate regression estimates to compare employment history, and potential barriers to and facilitators of employment between individuals with psychiatric and physical disabilities. VR applicants with psychiatric disabilities have had longer periods of nonemployment than individuals with physical disabilities alone. They are significantly more likely than individuals with physical disabilities alone to report nonhealth reasons, such as getting fired and lacking skills, as barriers to employment. We found that a number of accommodations, including flexible schedules and modified work duties, are significantly associated with continued employment. VR counselors should be aware that although most applicants with psychiatric disabilities place a great deal of importance on being employed, they face additional barriers to employment. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Effect of different intraorifice barriers on the fracture resistance of roots obturated with Resilon or gutta-percha.

PubMed

Nagas, Emre; Uyanik, Ozgur; Altundasar, Emre; Durmaz, Veli; Cehreli, Zafer C; Vallittu, Pekka K; Lassila, Lippo V J

2010-06-01

This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon. Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests. Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P < .05), but not by the type of obturation system used (P > .05). The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Physical, mechanical, and barrier properties of sodium alginate/gelatin emulsion based-films incorporated with canola oil

NASA Astrophysics Data System (ADS)

Syarifuddin, A.; Hasmiyani; Dirpan, A.; Mahendradatta, M.

2017-12-01

The development of mixed emulsion-based films formed by sodium alginate/gelatin incorporated with canola oil can offer particular properties such as water vapor barrier properties. The different ratios of sodium alginate/gelatin and sodium alginate/gelatin emulsion-based films incorporated with canola oil were developed and their effects on films’ physical, mechanical and barrier properties were assessed. Here we set out to examine whether canola oil addition and different ratio of sodium alginate/gelatin modified physical, mechanical, and barrier properties of films. To do so, the films were prepared by vary the ratio of sodium alginate/gelatin (2.5, 1, 0.5). Canola oil addition induced changes in moisture content, thickness, solubility, water vapor transmission rate (WVTR), percent elongation at break (p<0.05). In addition, it is apparent that varying ratio of sodium alginate to gelatin induced change the mechanical properties of films. The reduction of sodium alginate to gelatin decreased the tensile strength of both films. Improved values of WVTR, tensile strength and solubility at break were observed when the ratio of sodium alginate/gelatin emulsion film incorporated with canola oil was 2.5. Therefore, different ratio of sodium alginate/gelatin incorporated with canola oil can be used to tailor emulsion films with enhanced water vapor barrier and mechanical properties.

Review. Specificity in pollination and consequences for postmating reproductive isolation in deceptive Mediterranean orchids.

PubMed

Cozzolino, Salvatore; Scopece, Giovanni

2008-09-27

The type of reproductive isolation prevalent in the initial stages of species divergence can affect the nature and rate of emergence of additional reproductive barriers that subsequently strengthen isolation between species. Different groups of Mediterranean deceptive orchids are characterized by different levels of pollinator specificity. Whereas food-deceptive orchid species show weak pollinator specificity, the sexually deceptive Ophrys species display a more specialized pollination strategy. Comparative analyses reveal that orchids with high pollinator specificity mostly rely on premating reproductive barriers and have very little postmating isolation. In this group, a shift to a novel pollinator achieved by modifying the odour bouquet may represent the main isolation mechanism involved in speciation. By contrast, orchids with weak premating isolation, such as generalized food-deceptive orchids, show strong evidence for intrinsic postmating reproductive barriers, particularly for late-acting postzygotic barriers such as hybrid sterility. In such species, chromosomal differences may have played a key role in species isolation, although strong postmating-prezygotic isolation has also evolved in these orchids. Molecular analyses of hybrid zones indicate that the types and strength of reproductive barriers in deceptive orchids with contrasting premating isolation mechanisms directly affect the rate and evolutionary consequences of hybridization and the nature of species differentiation.

Surface modifications on InAs decrease indium and arsenic leaching under physiological conditions

NASA Astrophysics Data System (ADS)

Jewett, Scott A.; Yoder, Jeffrey A.; Ivanisevic, Albena

2012-11-01

Devices containing III-V semiconductors such as InAs are increasingly being used in the electronic industry for a variety of optoelectronic applications. Furthermore, the attractive chemical, material, electronic properties make such materials appealing for use in devices designed for biological applications, such as biosensors. However, in biological applications the leaching of toxic materials from these devices could cause harm to cells or tissue. Additionally, after disposal, toxic inorganic materials can leach from devices and buildup in the environment, causing long-term ecological harm. Therefore, the toxicity of these materials along with their stability in physiological conditions are important factors to consider. Surface modifications are one common method of stabilizing semiconductor materials in order to chemically and electronically passivate them. Such surface modifications could also prevent the leaching of toxic materials by preventing the regrowth of the unstable surface oxide layer and by creating an effective barrier between the semiconductor surface and the surrounding environment. In this study, various surface modifications on InAs are developed with the goal of decreasing the leaching of indium and arsenic. The leaching of indium and arsenic from modified substrates was assessed in physiological conditions using inductively coupled plasma mass spectrometry (ICP-MS). Substrates modified with 11-mercapto-1-undecanol (MU) and graft polymerized with poly(ethylene) glycol (PEG) were most effective at preventing indium and arsenic leaching. These surfaces were characterized using contact angle analysis, ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Substrates modified with collagen and synthetic polyelectrolytes were least effective, due to the destructive nature of acidic environments on InAs. The toxicity of modified and unmodified InAs, along with raw indium, arsenic, and PEG components was assessed using zebrafish embryos.

Barriers Influencing Linkage to Hypertension Care in Kenya: Qualitative Analysis from the LARK Hypertension Study.

PubMed

Naanyu, Violet; Vedanthan, Rajesh; Kamano, Jemima H; Rotich, Jackson K; Lagat, Kennedy K; Kiptoo, Peninah; Kofler, Claire; Mutai, Kennedy K; Bloomfield, Gerald S; Menya, Diana; Kimaiyo, Sylvester; Fuster, Valentin; Horowitz, Carol R; Inui, Thomas S

2016-03-01

Hypertension, the leading global risk factor for mortality, is characterized by low treatment and control rates in low- and middle-income countries. Poor linkage to hypertension care contributes to poor outcomes for patients. However, specific factors influencing linkage to hypertension care are not well known. To evaluate factors influencing linkage to hypertension care in rural western Kenya. Qualitative research study using a modified Health Belief Model that incorporates the impact of emotional and environmental factors on behavior. Mabaraza (traditional community assembly) participants (n = 242) responded to an open invitation to residents in their respective communities. Focus groups, formed by purposive sampling, consisted of hypertensive individuals, at-large community members, and community health workers (n = 169). We performed content analysis of the transcripts with NVivo 10 software, using both deductive and inductive codes. We used a two-round Delphi method to rank the barriers identified in the content analysis. We selected factors using triangulation of frequency of codes and themes from the transcripts, in addition to the results of the Delphi exercise. Sociodemographic characteristics of participants were summarized using descriptive statistics. We identified 27 barriers to linkage to hypertension care, grouped into individual (cognitive and emotional) and environmental factors. Cognitive factors included the asymptomatic nature of hypertension and limited information. Emotional factors included fear of being a burden to the family and fear of being screened for stigmatized diseases such as HIV. Environmental factors were divided into physical (e.g. distance), socioeconomic (e.g. poverty), and health system factors (e.g. popularity of alternative therapies). The Delphi results were generally consistent with the findings from the content analysis. Individual and environmental factors are barriers to linkage to hypertension care in rural western Kenya. Our analysis provides new insights and methodological approaches that may be relevant to other low-resource settings worldwide.

Asymptotic and near-target direct breakup of 6Li and 7Li

NASA Astrophysics Data System (ADS)

Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.

2016-04-01

Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.

Early mobilization of critically ill adults: a survey of knowledge, perceptions and practices of Canadian physicians and physiotherapists

PubMed Central

Koo, Karen K.Y.; Choong, Karen; Cook, Deborah J.; Herridge, Margaret; Newman, Anastasia; Lo, Vincent; Guyatt, Gordon; Priestap, Fran; Campbell, Eileen; Burns, Karen E.A.; Lamontagne, FranÇois; Meade, Maureen O.

2016-01-01

Background: The promotion of early mobilization following critical illness is tempered by national reports of patient and institutional barriers to this approach. We carried out a survey to assess current knowledge, perceptions and practices of Canadian physicians and physiotherapists with respect to acquired weakness and early mobilization in adults in the intensive care unit (ICU). Methods: We conducted a cross-sectional, self-administered postal survey among critical care physicians and physiotherapists in all 46 academic ICUs in Canada in 2011-2012. To identify all physicians and physiotherapists working in the ICUs, we contacted division heads and senior physiotherapists by telephone or email. We designed, tested and administered a questionnaire with the following domains: knowledge of ICU-acquired weakness and early mobilization; personal views of, perceived barriers to and adequacy of technical skills for early mobilization; assessments for initiation of early mobilization and permissible activity levels by patient physiologic characteristics, diagnoses and therapies; staffing issues; and sedation practices. Results: The overall response rate was 71.3% (311/436); it was 64.2% (194/302) among physicians and 87.3% (117/134) among physiotherapists. A total of 214 respondents (68.8%) underestimated the incidence of ICU-acquired weakness in the general medical-surgical ICU population, and 186 (59.8%) stated they had insufficient knowledge or skills to mobilize patients receiving mechanical ventilation. Excessive sedation, medical instability, limited staffing, safety concerns, insufficient guidelines and insufficient equipment were common perceived barriers to early mobilization. Interpretation: Physicians and physiotherapists in the ICU underestimated the incidence of ICU-acquired weakness and felt inadequately trained to mobilize patients receiving mechanical ventilation. We identified multiple modifiable barriers to early mobilization at the institutional, health care provider and patient levels that need to be addressed when designing mobilization programs for critically ill adults. PMID:27730109

Device and method for producing a containment barrier underneath and around in-situ buried waste

DOEpatents

Gardner, B.M.; Smith, A.M.; Hanson, R.W.; Hodges, R.T.

1998-08-11

An apparatus is described for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably on which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground and injection means for inserting barrier-forming material into the void. In one embodiment, the digging means is a continuous cutting chain. Mounted on the continuous cutting chain are cutter teeth for cutting through soil and discharge paddles for removing the loosened soil. This invention includes a barrier placement machine, a method for building an underground horizontal containment barrier using the barrier placement machine, and the underground containment system. Preferably the underground containment barrier goes underneath and around the site to be contained in a bathtub-type containment. 15 figs.

Clinical Applications Involving CNS Gene Transfer

PubMed Central

Kantor, Boris; McCown, Thomas; Leone, Paola; Gray, Steven J.

2015-01-01

Diseases of the central nervous system (CNS) have traditionally been the most difficult to treat by traditional pharmacological methods, due mostly to the blood–brain barrier and the difficulties associated with repeated drug administration targeting the CNS. Viral vector gene transfer represents a way to permanently provide a therapeutic protein within the nervous system after a single administration, whether this be a gene replacement strategy for an inherited disorder or a disease-modifying protein for a disease such as Parkinson's. Gene therapy approaches for CNS disorders has evolved considerably over the last two decades. Although a breakthrough treatment has remained elusive, current strategies are now considerably safer and potentially much more effective. This chapter will explore the past, current, and future status of CNS gene therapy, focusing on clinical trials utilizing adeno-associated virus and lentiviral vectors. PMID:25311921

Oblique wave trapping by vertical permeable membrane barriers located near a wall

NASA Astrophysics Data System (ADS)

Koley, Santanu; Sahoo, Trilochan

2017-12-01

The effectiveness of a vertical partial flexible porous membrane wave barrier located near a rigid vertical impermeable seawall for trapping obliquely incident surface gravity waves are analyzed in water of uniform depth under the assumption of linear water wave theory and small amplitude membrane barrier response. From the general formulation of the submerged membrane barrier, results for bottom-standing and surface-piercing barriers are computed and analyzed in special cases. Using the eigenfunction expansion method, the boundary-value problems are converted into series relations and then the required unknowns are obtained using the least squares approximation method. Various physical quantities of interests like reflection coefficient, wave energy dissipation, wave forces acting on the membrane barrier and the seawall are computed and analyzed for different values of the wave and structural parameters. The study will be useful in the design of the membrane wave barrier for the creation of tranquility zone in the lee side of the barrier to protect the seawall.

Investigating the use of small-diameter softwood as guardrail posts (dynamic test results)

Treesearch

Jason A. Hascall; John D. Reid; Ronald K. Faller; Dean L. Sicking; David E. Kretschmann

2007-01-01

A modified version of the Midwest Guardrail System (MGS), utilizing small-diameter round wood posts, was developed, tested, and evaluated. Three systems were developed using different species of timber, Douglas Fir, Ponderosa Pine, and Southern Yellow Pine. A combination of Barrier VII computer simulation modeling and several series of cantilever bogie tests, conducted...

41 CFR 102-76.90 - Who has the authority to waive or modify the standards in § 102-76.65(a)?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Who has the authority to... Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 76-DESIGN AND CONSTRUCTION Architectural Barriers Act § 102-76.90 Who has the...

41 CFR 102-76.90 - Who has the authority to waive or modify the standards in § 102-76.65(a)?

Code of Federal Regulations, 2014 CFR

2014-01-01

... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Who has the authority to... Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 76-DESIGN AND CONSTRUCTION Architectural Barriers Act § 102-76.90 Who has the...

41 CFR 102-76.90 - Who has the authority to waive or modify the standards in § 102-76.65(a)?

Code of Federal Regulations, 2012 CFR

2012-01-01

... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Who has the authority to... Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 76-DESIGN AND CONSTRUCTION Architectural Barriers Act § 102-76.90 Who has the...

41 CFR 102-76.90 - Who has the authority to waive or modify the standards in § 102-76.65(a)?

Code of Federal Regulations, 2011 CFR

2011-01-01

... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Who has the authority to... Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 76-DESIGN AND CONSTRUCTION Architectural Barriers Act § 102-76.90 Who has the...

Sex, Age, and Race/Ethnicity Do Not Modify the Effectiveness of a Diet Intervention among Family Members of Hospitalized Cardiovascular Disease Patients

ERIC Educational Resources Information Center

Mochari-Greenberger, Heidi; Terry, Mary Beth; Mosca, Lori

2011-01-01

Objective: To determine whether effectiveness of a diet intervention for family members of cardiovascular disease patients varies by participant sex, race/ethnicity, or age because these characteristics have been associated with unique barriers to diet change. Design: Randomized controlled trial. Setting and Participants: University medical…

Perceived Barriers and Strategies to Effective Online Earth and Space Science Instruction

ERIC Educational Resources Information Center

Pottinger, James E.

2012-01-01

With the continual growth and demand of online courses, higher education institutions are attempting to meet the needs of today's learners by modifying and developing new student centered services and programs. As a result, faculty members are being forced into teaching online, including Earth and Space science faculty. Online Earth and Space…

Digital Skills Acquisition: Future Trends among Older Adults

ERIC Educational Resources Information Center

Gilliam, Brian K.

2011-01-01

Purpose: The purpose of this study was to identify future trends and barriers that will either facilitate or impede the narrowing of the digital skills divide among older adults during the next 10 years. Methodology: To address the research questions, this study used a modified version of the Delphi process using a panel of experts who…

41 CFR 102-76.90 - Who has the authority to waive or modify the standards in § 102-76.65(a)?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Who has the authority to... Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 76-DESIGN AND CONSTRUCTION Architectural Barriers Act § 102-76.90 Who has the...

Nature-based care opportunities and barriers in oncology contexts: a modified international e-Delphi survey.

PubMed

Blaschke, Sarah; O'Callaghan, Clare C; Schofield, Penelope

2017-10-16

To develop recommendations regarding opportunities and barriers for nature-based care in oncology contexts using a structured knowledge generation process involving relevant healthcare and design experts. Four-round modified electronic Delphi study. Oncology patients' nature-based recommendations, uncovered in preceding qualitative investigation, were included in the first round for the expert participants' consideration. Key items (opportunities and barriers) were developed using data aggregation and synthesis, followed by item prioritisation and 10-point Likert scale ranking (1=not important, 10=very important). Descriptive statistics were calculated to assess items of highest importance representing expert recommendations. Online Delphi process constituting an electronic international survey. A purposive sample of 200 potential panellists (recruitment target n=40) comprising healthcare practitioners, managers, designers, architects and researchers were invited to participate; experts were identified via research networks, snowballing and systematic literature review. 38 experts across seven countries (Australia, USA, UK, New Zealand, Canada, Denmark and Sweden) returned questionnaire 1, which determined consent and acceptance for participation. Initial response rate was 19%, and subsequent response rates were 84%, 82% and 84% for rounds 2, 3 and 4, respectively. The Delphi panel developed recommendations consisting of 10 opportunities and 10 barriers. The following opportunities were rated to be of highest importance: window views from clinical areas onto nature; outdoor settings, gardens and courtyards with easy and effortless access; and nature-based physical exercise adapted to patient requirements. Highest-rated barriers for nature-based oncology care included lack of knowledge and awareness about benefits of nature engagement and inaccessibility, not considering access requirements for the very sick and frail. Experts suggested and agreed on a set of recommendations, which represent critical considerations for the safe adoption of nature-based oncology opportunities. These findings fill a gap in understanding about helpful nature-based oncology care and may translate into oncology design and innovation. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

"We get them up, moving, and out the door. How do we get them to do what is recommended?" Using behaviour change theory to put exercise evidence into action for rehabilitation professionals.

PubMed

McArthur, Caitlin; Ziebart, Christina; Papaioannou, Alexandra; Cheung, Angela M; Laprade, Judi; Lee, Linda; Jain, Ravi; Giangregorio, Lora M

2018-01-25

Recommendations suggest a multicomponent exercise for people with osteoporosis. We identified rehabilitation professionals' barriers and facilitators to implementing exercise recommendations with people with osteoporosis, and used those to make suggestions for targeted knowledge translation interventions. Future work will report on development and evaluation of the interventions informed by our study. Rehabilitation professionals can help people with osteoporosis to engage in a multicomponent exercise program and perform activities of daily living safely. However, rehabilitation professional face barriers to implementing exercise evidence, especially for specific disease conditions like osteoporosis. We performed a behavioural analysis and identified rehabilitation professionals' barriers to and facilitators of implementing disease-specific physical activity and exercise recommendations (Too Fit to Fracture recommendations), and used the Behaviour Change Wheel to select interventions. Semi-structured interviews and focus groups were conducted with rehabilitation professionals, including physical therapists, kinesiologists, and occupational therapists, and transcribed verbatim. Two researchers coded data and identified emerging themes. Using the Behaviour Change Wheel framework, themes were categorized into capability, opportunity, and motivation, and relevant interventions were identified. Ninety-four rehabilitation professionals (mean age 40.5 years, 88.3% female) participated. Identified barriers were as follows: capability-lack of training in behaviour change, how to modify recommendations for physical and cognitive impairments; opportunity-lack of resources, time, and team work; motivation-lack of trust between providers, fear in providing interventions that may cause harm. Interventions selected were as follows: education, training, enablement, modelling and persuasion. Policy categories are communication/marketing, guidelines, service provision and environmental/social planning. Key barriers to implementing the recommendations are rehabilitation professionals' ability to use behaviour change techniques, to modify the recommendations for physical and cognitive limitations and to feel comfortable with delivering challenging but safe interventions for people with osteoporosis, and lacking trust and team work across sectors. Future work will report on development and evaluation of knowledge translation interventions informed by our study.

Method for contamination control and barrier apparatus with filter for containing waste materials that include dangerous particulate matter

DOEpatents

Pinson, Paul A.

1998-01-01

A container for hazardous waste materials that includes air or other gas carrying dangerous particulate matter has incorporated in barrier material, preferably in the form of a flexible sheet, one or more filters for the dangerous particulate matter sealably attached to such barrier material. The filter is preferably a HEPA type filter and is preferably chemically bonded to the barrier materials. The filter or filters are preferably flexibly bonded to the barrier material marginally and peripherally of the filter or marginally and peripherally of air or other gas outlet openings in the barrier material, which may be a plastic bag. The filter may be provided with a backing panel of barrier material having an opening or openings for the passage of air or other gas into the filter or filters. Such backing panel is bonded marginally and peripherally thereof to the barrier material or to both it and the filter or filters. A coupling or couplings for deflating and inflating the container may be incorporated. Confining a hazardous waste material in such a container, rapidly deflating the container and disposing of the container, constitutes one aspect of the method of the invention. The chemical bonding procedure for producing the container constitutes another aspect of the method of the invention.

Method for contamination control and barrier apparatus with filter for containing waste materials that include dangerous particulate matter

DOEpatents

Pinson, P.A.

1998-02-24

A container for hazardous waste materials that includes air or other gas carrying dangerous particulate matter has incorporated barrier material, preferably in the form of a flexible sheet, and one or more filters for the dangerous particulate matter sealably attached to such barrier material. The filter is preferably a HEPA type filter and is preferably chemically bonded to the barrier materials. The filter or filters are preferably flexibly bonded to the barrier material marginally and peripherally of the filter or marginally and peripherally of air or other gas outlet openings in the barrier material, which may be a plastic bag. The filter may be provided with a backing panel of barrier material having an opening or openings for the passage of air or other gas into the filter or filters. Such backing panel is bonded marginally and peripherally thereof to the barrier material or to both it and the filter or filters. A coupling or couplings for deflating and inflating the container may be incorporated. Confining a hazardous waste material in such a container, rapidly deflating the container and disposing of the container, constitutes one aspect of the method of the invention. The chemical bonding procedure for producing the container constitutes another aspect of the method of the invention. 3 figs.

Career Barriers Perceived by Hard-of-Hearing Adolescents: Implications for Practice From a Mixed-Methods Study

ERIC Educational Resources Information Center

Punch, Renee; Creed, Peter A.; Hyde, Merv B.

2006-01-01

This study incorporated both quantitative and qualitative methods to examine the perception of career barriers by hard-of-hearing high school students being educated in regular classes with itinerant teacher support. Sixty-five students in Years 10, 11, and 12 completed a questionnaire about potential general and hearing-related barriers, and 12…

Complementary Barrier Infrared Detector (CBIRD) Contact Methods

NASA Technical Reports Server (NTRS)

Ting, David Z.; Hill, Cory J.; Gunapala, Sarath D.

2013-01-01

The performance of the CBIRD detector is enhanced by using new device contacting methods that have been developed. The detector structure features a narrow gap adsorber sandwiched between a pair of complementary, unipolar barriers that are, in turn, surrounded by contact layers. In this innovation, the contact adjacent to the hole barrier is doped n-type, while the contact adjacent to the electron barrier is doped p-type. The contact layers can have wider bandgaps than the adsorber layer, so long as good electrical contacts are made to them. If good electrical contacts are made to either (or both) of the barriers, then one could contact the barrier(s) directly, obviating the need for additional contact layers. Both the left and right contacts can be doped either n-type or ptype. Having an n-type contact layer next to the electron barrier creates a second p-n junction (the first being the one between the hole barrier and the adsorber) over which applied bias could drop. This reduces the voltage drop over the adsorber, thereby reducing dark current generation in the adsorber region.

Barriers to physical activity in chronic hemodialysis patients: a single-center pilot study in an Italian dialysis facility.

PubMed

Fiaccadori, Enrico; Sabatino, Alice; Schito, Franco; Angella, Francesca; Malagoli, Martina; Tucci, Marco; Cupisti, Adamasco; Capitanini, Alessandro; Regolisti, Giuseppe

2014-01-01

In patients on chronic dialysis a sedentary lifestyle is a strong, yet potentially modifiable, predictor of mortality. The present single-center pilot study evaluated social, psychological and clinical barriers that may hinder physical activity in this population. We explored the association between barriers to physical activity and sedentarism in adult patients at a chronic dialysis facility in Parma, Italy. We used different questionnaries exploring participation in physical activity, physical functioning, patient attitudes and preferences, and barriers to physical activity perceived by either patients or dialysis doctors and nurses. We enrolled 104 patients, (67 males, 65%), mean age 69 years (79% of patients older than 60 years); median dialysis vintage 60 months (range 8-440); mean Charlson score 5.55, ADL (Activities of Daily Living) score 5.5. Ninety-two participants (88.5%) reported at least one barrier to physical activity. At multivariable analysis, after adjusting for age and sex, feeling to have too many medical problems (OR 2.99, 95% CI 1.27 to 7.07; P=0.012), chest pain (OR 10.78, 95% CI 1.28 to 90.28; P=0.029) and sadness (OR 2.59, 95% CI 1.10 to 6.09; P=0.030) were independently associated with physical inactivity. Lack of time for exercise counseling and the firm belief about low compliance/interest by the patients toward exercise were the most frequent barriers reported by doctors and nurses. We identified a number of patient-related and health personnel-related barriers to physical activity in patients on chronic dialysis. Solutions for these barriers should be addressed in future studies aimed at increasing the level of physical activity in this population. © 2014 S. Karger AG, Basel.

Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout

NASA Astrophysics Data System (ADS)

Bläckberg, L.; El Fakhri, G.; Sabet, H.

2017-11-01

A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to  >42%, and for rough interfaces  >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically pixelated array 35% with polished pixel surfaces and 59% with rough surfaces.

Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout.

PubMed

Bläckberg, L; El Fakhri, G; Sabet, H

2017-10-19

A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to  >42%, and for rough interfaces  >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically pixelated array 35% with polished pixel surfaces and 59% with rough surfaces.

Engineering of Porphyrin Molecules for Use as Effective Cathode Interfacial Modifiers in Organic Solar Cells of Enhanced Efficiency and Stability.

PubMed

Tountas, Marinos; Verykios, Apostolis; Polydorou, Ermioni; Kaltzoglou, Andreas; Soultati, Anastasia; Balis, Nikolaos; Angaridis, Panagiotis A; Papadakis, Michael; Nikolaou, Vasilis; Auras, Florian; Palilis, Leonidas C; Tsikritzis, Dimitris; Evangelou, Evangelos K; Gardelis, Spyros; Koutsoureli, Matroni; Papaioannou, George; Petsalakis, Ioannis D; Kennou, Stella; Davazoglou, Dimitris; Argitis, Panagiotis; Falaras, Polycarpos; Coutsolelos, Athanassios G; Vasilopoulou, Maria

2018-06-20

In the present work, we effectively modify the TiO 2 electron transport layer of organic solar cells with an inverted architecture using appropriately engineered porphyrin molecules. The results show that the optimized porphyrin modifier bearing two carboxylic acids as the anchoring groups and a triazine electron-withdrawing spacer significantly reduces the work function of TiO 2 , thereby reducing the electron extraction barrier. Moreover, the lower surface energy of the porphyrin-modified substrate results in better physical compatibility between the latter and the photoactive blend. Upon employing porphyrin-modified TiO 2 electron transport layers in PTB7:PC 71 BM-based organic solar cells we obtained an improved average power conversion efficiency up to 8.73%. Importantly, porphyrin modification significantly increased the lifetime of the devices, which retained 80% of their initial efficiency after 500 h of storage in the dark. Because of its simplicity and efficacy, this approach should give tantalizing glimpses and generate an impact into the potential of porphyrins to facilitate electron transfer in organic solar cells and related devices.

Intumescent coatings with improved properties for high-rise construction

NASA Astrophysics Data System (ADS)

Ustinov, Andrey; Zybina, Olga; Tanklevsky, Leonid; Lebedev, Vasily; Andreev, Andrey

2018-03-01

The paper overviews the way of creating intumescent fire-protective compositions with improved properties by adding nano-and micro-sized supplements into them. Intumescent paints are inert at low temperatures, and at higher temperatures they expand and degrade to provide a charred layer of low conductivity materials. The modified intumescent paints are able to form a more stable charred layer than the classical paints. The stability of a charred layer is crucial if the fire safety in high-rise construction must be secured, because a weak charred layer will not provide a required fire endurance for steel bearing structures and they will break down in case of fire. The fire-protective properties of modified intumescent paints were estimated using an electrical furnace. Also the way of thermal decomposition of the paints was studied with thermogravimetric analysis. Results show that modified intumescent paints form a charred layer with improved fire-protective properties; it can serve as a thermal barrier for a longer period of time. Thermogravimetric analysis confirms this fact showing that the temperatures of full thermal decay in case of modified paints are higher than those of non-modified paints.

Analysis of the Barrier Properties of Polyimide-Silicate Nanocomposites

NASA Technical Reports Server (NTRS)

Campbell, Sandi; Johnston, J. Chris; Inghram, Linda; McCorkle, Linda; Silverman, Edward

2003-01-01

Montmorillonite clay was organically modified and dispersed into a thermoplastic (BPADA-BAPP) and a thermosetting (PMR-15) polyimide matrix. The barrier properties of the neat resins and the nanocomposites were evaluated. Reductions in gas permeability and water absorption were observed in thermoplastic polyimide nanocomposites. The thermosetting polyimide showed a reduction in weight loss during isothermal aging at 288 C. Carbon fabric (T650-35, 8 HS, 8 ply) composites were prepared using both the BPADE-BAPP and PMR-15 based nanocomposites. Dispersion of the layered silicate in the BPADA-BAPP matrix reduced helium permeability by up to 70 percent. The PMR-15/ silicate nanocomposite matrix had an increase in thermal oxidative stability of up to 25 percent.

Oil spill cleanup method and apparatus

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

Mayes, F.M.

1980-06-24

A method for removing oil from the surface of water where an oil spill has occurred, particularly in obstructed or shallow areas, which comprises partially surrounding a hovercraft with a floating oil-collecting barrier, there being no barrier at the front of the hovercraft, moving the oil-barrier-surrounded-hovercraft into oil contaminated water, and collecting oil gathered within the barrier behind the hovercraft through a suction line which carries the oil to a storage tank aboard the hovercraft. The invention also embodies the hovercraft adapted to effect an oil spill cleanup.

Multilayer thermal barrier coating systems

DOEpatents

Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

2000-01-01

The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.

Testing the Feasibility of a Passive and Active Case Ascertainment System for Multiple Rare Conditions Simultaneously: The Experience in Three US States

PubMed Central

McDermott, Suzanne; Ruttenber, Margaret; Mann, Joshua; Smith, Michael G; Royer, Julie; Valdez, Rodolfo

2016-01-01

Background Owing to their low prevalence, single rare conditions are difficult to monitor through current state passive and active case ascertainment systems. However, such monitoring is important because, as a group, rare conditions have great impact on the health of affected individuals and the well-being of their caregivers. A viable approach could be to conduct passive and active case ascertainment of several rare conditions simultaneously. This is a report about the feasibility of such an approach. Objective To test the feasibility of a case ascertainment system with passive and active components aimed at monitoring 3 rare conditions simultaneously in 3 states of the United States (Colorado, Kansas, and South Carolina). The 3 conditions are spina bifida, muscular dystrophy, and fragile X syndrome. Methods Teams from each state evaluated the possibility of using current or modified versions of their local passive and active case ascertainment systems and datasets to monitor the 3 conditions. Together, these teams established the case definitions and selected the variables and the abstraction tools for the active case ascertainment approach. After testing the ability of their local passive and active case ascertainment system to capture all 3 conditions, the next steps were to report the number of cases detected actively and passively for each condition, to list the local barriers against the combined passive and active case ascertainment system, and to describe the experiences in trying to overcome these barriers. Results During the test period, the team from South Carolina was able to collect data on all 3 conditions simultaneously for all ages. The Colorado team was also able to collect data on all 3 conditions but, because of age restrictions in its passive and active case ascertainment system, it was able to report few cases of fragile X syndrome. The team from Kansas was able to collect data only on spina bifida. For all states, the implementation of an active component of the ascertainment system was problematic. The passive component appears viable with minor modifications. Conclusions Despite evident barriers, the joint passive and active case ascertainment of rare disorders using modified existing surveillance systems and datasets seems feasible, especially for systems that rely on passive case ascertainment. PMID:27574026

Development of the Motivators of and Barriers to Health-Smart Behaviors Inventory.

PubMed

Tucker, Carolyn M; Rice, Kenneth G; Hou, Wei; Kaye, Lillian B; Nolan, Sarah E M; Grandoit, Delphia J; Gonzales, Lucia; Smith, Mary B; Desmond, Frederic F

2011-06-01

The Motivators of and Barriers to Health-Smart Behaviors Inventory (MB-HSBI) was developed for use in identifying self-reported motivators of and barriers to the following health-promoting behaviors (called health-smart behaviors) that should occur daily to help promote health and overcome illnesses/diseases: eating a healthy breakfast, eating healthy foods and snacks, drinking healthy drinks, and engaging in physical activity. The MB-HSBI was developed through several phases as part of a multisite study on modifying and preventing obesity. A central aspect of the larger study was to identify motivators of and barriers to the targeted health-smart behaviors among African American, Asian, Hispanic, and White adults. After establishing content validity and preliminary pilot testing, the MB-HSBI was administered to a national sample of 926 culturally diverse adults. Factor analyses and most of the internal consistency results supported multiple scales and subscales measuring motivators of and barriers to each of the targeted health-smart behavior domains. Scores correlated in expected directions with health self-efficacy and with importance of health-related behavioral goals. Pending further psychometric support of the MB-HSBI, this inventory or selected scales from it may serve as flexible and novel tools for (a) assessing motivators of and barriers to health-smart behaviors in community and clinical health promotion research studies and (b) developing assessment-based, culturally sensitive intervention programs that are customized to address the motivators of and barriers to health-smart behaviors identified in target communities, particularly those communities whose members are mostly racial/ethnic minorities and/or have low family incomes. 2011 APA, all rights reserved

Health worker perspectives on barriers to delivery of routine tuberculosis diagnostic evaluation services in Uganda: a qualitative study to guide clinic-based interventions.

PubMed

Cattamanchi, Adithya; Miller, Cecily R; Tapley, Asa; Haguma, Priscilla; Ochom, Emmanuel; Ackerman, Sara; Davis, J Lucian; Katamba, Achilles; Handley, Margaret A

2015-01-22

Studies of the quality of tuberculosis (TB) diagnostic evaluation of patients in high burden countries have generally shown poor adherence to international or national guidelines. Health worker perspectives on barriers to improving TB diagnostic evaluation are critical for developing clinic-level interventions to improve guideline implementation. We conducted structured, in-depth interviews with staff at six district-level health centers in Uganda to elicit their perceptions regarding barriers to TB evaluation. Interviews were transcribed, coded with a standardized framework, and analyzed to identify emergent themes. We used thematic analysis to develop a logic model depicting health system and contextual barriers to recommended TB evaluation practices. To identify possible clinic-level interventions to improve TB evaluation, we categorized findings into predisposing, enabling, and reinforcing factors as described by the PRECEDE model, focusing on potentially modifiable behaviors at the clinic-level. We interviewed 22 health center staff between February 2010 and November 2011. Participants identified key health system barriers hindering TB evaluation, including: stock-outs of drugs/supplies, inadequate space and infrastructure, lack of training, high workload, low staff motivation, and poor coordination of health center services. Contextual barrier challenges to TB evaluation were also reported, including the time and costs borne by patients to seek and complete TB evaluation, poor health literacy, and stigma against patients with TB. These contextual barriers interacted with health system barriers to contribute to sub-standard TB evaluation. Examples of intervention strategies that could address these barriers and are related to PRECEDE model components include: assigned mentors/peer coaching for new staff (targets predisposing factor of low motivation and need for support to conduct job duties); facilitated workshops to implement same day microscopy (targets enabling factor of patient barriers to completing TB evaluation), and recognition/incentives for good TB screening practices (targets low motivation and self-efficacy). Our findings suggest that health system and contextual barriers work together to impede TB diagnosis at health centers and, if not addressed, could hinder TB case detection efforts. Qualitative research that improves understanding of the barriers facing TB providers is critical to developing targeted interventions to improve TB care.

Method of manufacturing lightweight thermo-barrier material

NASA Technical Reports Server (NTRS)

Blair, Winford (Inventor)

1987-01-01

A method of manufacturing thermal barrier structures comprising at least three dimpled cores separated by flat plate material with the outer surface of the flat plate material joined together by diffusion bonding.

Modifying physician behavior to improve cost-efficiency in safety-net ambulatory settings.

PubMed

Borkowski, Nancy; Gumus, Gulcin; Deckard, Gloria J

2013-01-01

Change interventions in one form or another are viewed as important tools to reduce variation in medical services, reduce costs, and improve quality of care. With the current focus on efficient resource use, the successful design and implementation of change strategies are of utmost importance for health care managers. We present a case study in which macro and micro level change strategies were used to modify primary care physicians' practice patterns of prescribing diagnostic services in a safety-net's ambulatory clinics. The findings suggest that health care managers using evidence-based strategies can create a practice environment that reduces barriers and facilitates change.

Effects of different sterilization methods on the physico-chemical and bioresponsive properties of plasma-treated polycaprolactone films.

PubMed

Ghobeira, Rouba; Philips, Charlot; Declercq, Heidi; Cools, Pieter; De Geyter, Nathalie; Cornelissen, Ria; Morent, Rino

2017-01-24

For most tissue engineering applications, surface modification and sterilization of polymers are critical aspects determining the implant success. The first part of this study is thus dedicated to modifying polycaprolactone (PCL) surfaces via plasma treatment using a medium pressure dielectric barrier discharge, while the second part focuses on the sterilization of plasma-modified PCL. Chemical and physical surface changes are examined making use of water contact angle goniometry (WCA), x-ray photoelectron spectroscopy and atomic force microscopy. Bioresponsive properties are evaluated by performing cell culture tests. The results show that air and argon plasmas decrease the WCA significantly due to the incorporation of oxygen-containing functionalities onto the PCL surface, without modifying its morphology. Extended treatment times lead to PCL degradation, especially in the case of air plasma. In addition to surface modification, the plasma potential to sterilize PCL is studied with appropriate treatment times, but sterility has not been achieved so far. Therefore, plasma-modified films are subjected to UV, H 2 O 2 plasma (HP) and ethylene oxide (EtO) sterilizations. UV exposure of 3 h does not alter the PCL physico-chemical properties. A decreased wettability is observed after EtO sterilization, attributable to the modification of PCL chain ends reacting with EtO molecules. HP sterilization increases the WCA of the plasma-treated samples, presumably due to the scission of the hydrophilic bonds generated during the prior plasma treatments. Moreover, HP modifies the PCL surface morphology. For all the sterilizations, an improved cell adhesion and proliferation is observed on plasma-treated films compared to untreated ones. EtO shows the lowest proliferation rate compared to HP and UV. Overall, of the three sterilizations, UV is the most effective, since the physical alterations provoked by HP might interfere with the structural integrity when it comes to 3D scaffolds, and the chemical modifications caused by EtO, in addition to its toxicity, interfere with PCL bioactivity.

Physico-Chemical Properties and Biodegradability of Genetically Modified Populus trichocarpa and Pinus taeda

NASA Astrophysics Data System (ADS)

Edmunds, Charles Warren

Increasing concerns over greenhouse gas emissions and the finite supply of fossil fuels lead to the goal of utilizing lignocellulosic feedstocks for biofuels, platform chemicals, and biocomposites. Lignin is responsible for the recalcitrance of lignocellulosic biomass and is a major barrier to its deconstruction. Great progress has been made in mapping and modifying the lignin biosynthetic pathway. However, the link between the genetic modification, resulting chemical and physical properties of the wood, and how these properties influence the thermomechanical and recalcitrance to biological and chemical degradation needs further investigation. In this dissertation, the study of modified Populus trichocarpa and Pinus taeda were utilized to accomplish this goal. Thermo-mechanical properties of genetically modified P. trichocarpa with altered lignin content and/or lignin structure were measured with a series of tools including; dynamic mechanical analysis, nuclear magnetic resonance, and wet chemistry techniques. Results demonstrated lignin content and lignin structure likely influence the glass transition temperature (Tg), and that decreased lignin content and the corresponding higher proportion of cell wall carbohydrates may contribute to increased molecular mobility in the wood polymer structure. The effect of lignin biosynthetic pathway modification on biological degradation of these transgenic wood specimens was of interest. However, experimental methods for fungal treatment on small young greenhouse-grown wood specimens are not well established. Therefore, a project was undertaken to develop a method for fungal inoculation and incubation for these unique specimens. Several parameters were tested, and a fungal treatment method was identified with sufficient weight loss after decay and significant reduction in variation of weight loss between replicates compared to previous experiments by direct inoculation of wood with liquid malt extract fungal culture. Utilizing the fungal treatment method which was developed, fungal pretreatment as a potential low-input and environmentally-friendly alternative to conventional pretreatment methods was tested using the white-rot fungus, Ceriporiopsis subvermispora, on wildtype and transgenic P. trichocarpa. In addition to fungal treatment, hot water and dilute acid treatments followed by enzymatic hydrolysis was tested. Results showed no clear relationship between the initial lignin content or syringyl/guaiacyl lignin monomer ratio and weight loss due to fungal treatment. P-hydroxyphenyl lignin monomer degradation of up to 60% during the fungal treatment were observed in cinnamate 3-hydroxylase down-regulated genetic lines. It was demonstrated that fungal treatment in wildtype and several transgenic lines resulted in substantial improvements in sugar yields, up to 2.4-fold increase in glucose yield and 6.7-fold increase in xylose yield after enzymatic hydrolysis. However, some genetic lines showed little benefit from fungal pretreatment, and in general hot water and dilute acid pretreatments showed similar or increased glucose yield compared to fungal treatment. The goal of the last project was to characterize P. taeda which was genetically modified for S lignin production or decreased lignin content. In addition, the amenability to pretreatment and enzymatic hydrolysis were analyzed using hot water and dilute acid pretreatments followed by enzymatic hydrolysis. In the transgenic lines modified for production of syringyl lignin, Maule staining demonstrated the intermittent deposition of syringyl lignin in the secondary xylem, while thioacidolysis showed 13% concentration of S lignin, and solid state NMR demonstrated the occurrence of beta-O-4 linkages in S lignin units. In transgenic lines modified for reduced lignin content, lignin reduction up to 33% was observed, and pretreatment and enzymatic hydrolysis demonstrated increased cellulose conversion in lowlignin samples. These results highlight the potential of softwood to be a viable bioenergy/biochemical feedstock and opens up exciting new avenue of research.

Experimental and computational investigation of graphene/SAMs/n-Si Schottky diodes

NASA Astrophysics Data System (ADS)

Aydin, H.; Bacaksiz, C.; Yagmurcukardes, N.; Karakaya, C.; Mermer, O.; Can, M.; Senger, R. T.; Sahin, H.; Selamet, Y.

2018-01-01

We have investigated the effect of two different self-assembled monolayers (SAMs) on electrical characteristics of bilayer graphene (BLG)/n-Si Schottky diodes. Novel 4″bis(diphenylamino)-1, 1‧:3″-terphenyl-5‧ carboxylic acids (TPA) and 4,4-di-9H-carbazol-9-yl-1,1‧:3‧1‧-terphenyl-5‧ carboxylic acid (CAR) aromatic SAMs have been used to modify n-Si surfaces. Cyclic voltammetry (CV) and Kelvin probe force microscopy (KPFM) results have been evaluated to verify the modification of n-Si surface. The current-voltage (I-V) characteristics of bare and SAMs modified devices show rectification behaviour verifying a Schottky junction at the interface. The ideality factors (n) from ln(I)-V dependences were determined as 2.13, 1.96 and 2.07 for BLG/n-Si, BLG/TPA/n-Si and BLG/CAR/n-Si Schottky diodes, respectively. In addition, Schottky barrier height (SBH) and series resistance (Rs) of SAMs modified diodes were decreased compared to bare diode due to the formation of a compatible interface between graphene and Si as well as π-π interaction between aromatic SAMs and graphene. The CAR-based device exhibits better diode characteristic compared to the TPA-based device. Computational simulations show that the BLG/CAR system exhibits smaller energy-level-differences than the BLG/TPA, which supports the experimental findings of a lower Schottky barrier and series resistance in BLG/CAR diode.

Multifunctional Composites for Improved Polyimide Thermal Stability

NASA Technical Reports Server (NTRS)

Miller, Sandi G.

2007-01-01

The layered morphology of silicate clay provides an effective barrier to oxidative degradation of the matrix resin. However, as resin thermal stability continues to reach higher limits, development of an organic modification with comparable temperature capabilities becomes a challenge. Typically, phyllosilicates used in polymer nanocomposites are modified with an alkyl ammonium ion. Such organic modifiers are not suited for incorporation into high temperature polymers as they commonly degrade below 200oC. Therefore, the development of nanoparticle specifically suited for high temperature applications is necessary. Several nanoparticles were investigated in this study, including pre-exfoliated synthetic clay, an organically modified clay, and carbon nanofiber. Dispersion of the layered silicate increases the onset temperature of matrix degradation as well as slows oxidative degradation. The thermally stable carbon nanofibers are also observed to significantly increase the resin thermal stability.

Barrier methods of birth control - slideshow

MedlinePlus

... ency/presentations/100107.htm Barrier methods of birth control - series—Female normal anatomy To use the sharing ... M. Editorial team. Related MedlinePlus Health Topics Birth Control A.D.A.M., Inc. is accredited by ...

Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

DOEpatents

Lessing, Paul A [Idaho Falls, ID

2008-07-22

An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

DOEpatents

Lessing, Paul A.

2004-09-07

An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

Effect of various infection-control methods for light-cure units on the cure of composite resins.

PubMed

Chong, S L; Lam, Y K; Lee, F K; Ramalingam, L; Yeo, A C; Lim, C C

1998-01-01

This study (1) compared the curing-light intensity with various barrier infection-control methods used to prevent cross contamination, (2) compared the Knoop hardness value of cured composite resin when various barrier control methods were used, and (3) correlated the hardness of the composite resin with the light-intensity output when different infection-control methods were used. The light-cure unit tips were covered with barriers, such as cellophane wrap, plastic gloves, Steri-shields, and finger cots. The control group had no barrier. Composite resins were then cured for each of the five groups, and their Knoop hardness values recorded. The results showed that there was significant statistical difference in the light-intensity output among the five groups. However, there was no significant statistical difference in the Knoop hardness values among any of the groups. There was also no correlation between the Knoop hardness value of the composite resin with the light-intensity output and the different infection-control methods. Therefore, any of the five infection-control methods could be used as barriers for preventing cross-contamination of the light-cure unit tip, for the light-intensity output for all five groups exceeded the recommended value of 300 W/m2. However, to allow a greater margin of error in clinical situations, the authors recommend that the plastic glove or the cellophane wrap be used to wrap the light-cure tip, since these barriers allowed the highest light-intensity output.

Barriers that practitioners face when initiating insulin therapy in general practice settings and how they can be overcome

PubMed Central

Bin rsheed, Abdulaziz; Chenoweth, Ian

2017-01-01

AIM To explore primary care physicians’ perspectives on possible barriers to the use of insulin. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eight electronic databases were searched (between January 1, 1994 and August 31, 2014) for relevant studies. A search for grey literature and a review of the references in the retrieved studies were also conducted. Studies that focused on healthcare providers’ perspectives on possible barriers to insulin initiation with type 2 diabetic patients were included, as well as articles suggesting solutions for these barriers. Review articles and studies that only considered patients’ perspectives were excluded. RESULTS A total of 19 studies met the inclusion criteria and were therefore included in this study: 10 of these studies used qualitative methods, 8 used quantitative methods and 1 used mixed methods. Studies included a range of different health care settings. The findings are reported under four broad categories: The perceptions of primary care physicians about the barriers to initiate insulin therapy for type 2 diabetes patients, how primary care physicians assess patients prior to initiating insulin, professional roles and possible solutions to overcome these barriers. The barriers described were many and covered doctor, patient, system and technological aspects. Interventions that focused on doctor training and support, or IT-based decision support were few, and did not result in significant improvement. CONCLUSION Primary care physicians’ known delay in insulin initiation is multifactorial. Published reports of attempts to find solutions for these barriers were limited in number. PMID:28138362

Waste management barriers in developing country hospitals: Case study and AHP analysis.

PubMed

Delmonico, Diego V de Godoy; Santos, Hugo H Dos; Pinheiro, Marco Ap; de Castro, Rosani; de Souza, Regiane M

2018-01-01

Healthcare waste management is an essential field for both researchers and practitioners. Although there have been few studies using statistical methods for its evaluation, it has been the subject of several studies in different contexts. Furthermore, the known precarious practices for waste management in developing countries raise questions about its potential barriers. This study aims to investigate the barriers in healthcare waste management and their relevance. For this purpose, this paper analyses waste management practices in two Brazilian hospitals by using case study and the Analytic Hierarchy Process method. The barriers were organized into three categories - human factors, management, and infrastructure, and the main findings suggest that cost and employee awareness were the most significant barriers. These results highlight the main barriers to more sustainable waste management, and provide an empirical basis for multi-criteria evaluation of the literature.

Adjunctive Effect of Autologus Platelet-Rich Fibrin to Barrier Membrane in the Treatment of Periodontal Intrabony Defects.

PubMed

Panda, Saurav; Sankari, Malaiappan; Satpathy, Anurag; Jayakumar, Doraiswamy; Mozzati, Marco; Mortellaro, Carmen; Gallesio, Giorgia; Taschieri, Silvio; Del Fabbro, Massimo

2016-05-01

Autologous platelet-rich fibrin (PRF) and barrier membranes in the treatment of intrabony defects in chronic periodontitis patients have shown significant clinical benefits. This study evaluates the additive effect of autologous PRF in combination with a barrier membrane versus the use of barrier membrane alone for the treatment of intrabony defects in chronic periodontitis patients. A randomized split-mouth design was used. Sixteen patients with 32 paired intrabony defects were included. In each patient 1 defect was treated using a resorbable collagen membrane along with PRF (test group) and the other defect by guided tissue regeneration alone (control group). The following clinical parameters were measured at baseline and after 9 months: plaque index, modified sulcus bleeding index, probing pocket depth, clinical attachment level, and gingival marginal level. The radiographic defect depth was also assessed at baseline and after 9 months. Test group showed a statistically significant improvement for probing depth (P = 0.002), clinical attachment level (P = 0.001), and radiographic defect depth (P < 0.001) after 9 months as compared with the control sites. Radiographic defect depth reduction was 58.19 ± 13.24% in the test group as compared with 24.86 ± 9.94% reduction in the control group. The adjunctive use of PRF in combination with barrier membrane is more effective in the treatment of intrabony defects in chronic periodontitis as compared with barrier membrane alone.

Effects of Discipline-based Career Course on Nursing Students' Career Search Self-efficacy, Career Preparation Behavior, and Perceptions of Career Barriers.

PubMed

Park, Soonjoo

2015-09-01

The purpose of this study was to investigate the effectiveness of a discipline-based career course on perceptions of career barriers, career search self-efficacy, and career preparation behavior of nursing students. Differences in career search self-efficacy and career preparation behavior by the students' levels of career barriers were also examined. The study used a modified one-group, pretest-posttest design. The convenience sample consisted of 154 undergraduate nursing students in a university. The discipline-based career course consisted of eight sessions, and was implemented for 2 hours per session over 8 weeks. The data were collected from May to June in 2012 and 2013 using the following instruments: the Korean Career Indecision Inventory, the Career Search Efficacy Scale, and the Career Preparation Behavior Scale. Descriptive statistics, paired t test, and analysis of covariance were used to analyze the data. Upon the completion of the discipline-based career course, students' perceptions of career barriers decreased and career search self-efficacy and career preparation behavior increased. Career search self-efficacy and career preparation behavior increased in students with both low and high levels of career barriers. The difference between the low and high groups was significant for career search self-efficacy but not for career preparation behavior. The discipline-based career course was effective in decreasing perceptions of career barriers and increasing career search self-efficacy and career preparation behavior among nursing students. Copyright © 2015. Published by Elsevier B.V.

Barriers to accessing palliative care for pediatric patients with cancer: A review of the literature.

PubMed

Haines, Emily R; Frost, A Corey; Kane, Heather L; Rokoske, Franziska S

2018-06-01

Although many of the 16,000 children in the United States diagnosed who are with cancer each year could benefit from pediatric palliative care, these services remain underused. Evidence regarding the barriers impeding access to comprehensive palliative care is dispersed in the literature, and evidence specific to pediatric oncology remains particularly sparse. The purpose of the current review was to synthesize the existing literature regarding these barriers and the strategies offered to address them. The authors completed a literature search using the PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science databases. In total, 71 articles were reviewed. Barriers to accessing pediatric palliative care were categorized according to the 4 levels of a modified socioecological model (ie, barriers related to policy/payment, health systems, organizations, and individuals). Major themes identified at each level included: 1) the lack of consistent and adequate funding mechanisms at the policy/payment level, 2) the lack of pediatric palliative care programs and workforce at the health systems level, 3) difficulties integrating palliative care into existing pediatric oncology care models at the organizational level, and 4) the lack of knowledge about pediatric palliative care, discomfort with talking about death, and cultural differences between providers and patients and their families at the individual level. Recommendations to address each of the barriers identified in the literature are included. Cancer 2018;124:2278-88. © 2018 American Cancer Society. © 2018 American Cancer Society.

Effect of SiN x diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol-gel dip coating and reactive magnetron sputtering.

PubMed

Ghazzal, Mohamed Nawfal; Aubry, Eric; Chaoui, Nouari; Robert, Didier

2015-01-01

We investigate the effect of the thickness of the silicon nitride (SiN x ) diffusion barrier on the structural and photocatalytic efficiency of TiO2 films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO2 films produced using soft chemistry (sol-gel) and physical methods (reactive sputtering) are affected differentially by the intercalating SiN x diffusion barrier. Increasing the thickness of the SiN x diffusion barrier induced a gradual decrease of the crystallite size of TiO2 films obtained by the sol-gel process. However, TiO2 obtained using the reactive sputtering method showed no dependence on the thickness of the SiN x barrier diffusion. The SiN x barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO2 films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO2 films obtained by each process was discussed.

Women physicians as healthcare leaders: a qualitative study.

PubMed

Roth, Virginia R; Theriault, Anne; Clement, Chris; Worthington, Jim

2016-06-20

Purpose - The purpose of this paper is to explore the under-representation of women physicians in clinical leadership by examining the issue from their perspective. Design/methodology/approach - The authors used large group engagement methods to explore the experiences and perceptions of women physicians. In order to capture common themes across this group as a whole, participants were selected using purposeful sampling. Data were analysed using a structured thematic analysis procedure. Findings - This paper provides empirical insights into the influences affecting women physicians' decision to participate in leadership. The authors found that they often exclude themselves because the costs of leadership outweigh the benefits. Potential barriers unique to healthcare include the undervaluing of leadership by physician peers and perceived lack of support by nursing. Research limitations/implications - This study provides an in-depth examination of why women physicians are under-represented in clinical leadership from the perspective of those directly involved. Further studies are needed to confirm the generalizability of these findings and potential differences between demographic groups of physicians. Practical implications - Healthcare organizations seeking to increase the participation of women physicians in leadership should focus on modifying the perceived costs of leadership and highlighting the potential benefits. Large group engagement methods can be an effective approach to engage physicians on specific issues and mobilize grass-roots support for change. Originality/value - This exploratory study provides insights on the barriers and enablers to leadership specific to women physicians in the clinical setting. It provides a reference for healthcare organizations seeking to develop and diversify their leadership talent.

Enhancing Workplace Wellness Efforts to Reduce Obesity: A Qualitative Study of Low-Wage Workers in St Louis, Missouri, 2013–2014

PubMed Central

Eyler, Amy A.; Purnell, Jason Q.; Kinghorn, Anna M.; Herrick, Cynthia; Evanoff, Bradley A.

2015-01-01

Introduction The objective of this study was to examine workplace determinants of obesity and participation in employer-sponsored wellness programs among low-wage workers. Methods We conducted key informant interviews and focus groups with 2 partner organizations: a health care employer and a union representing retail workers. Interviews and focus groups discussed worksite factors that support or constrain healthy eating and physical activity and barriers that reduce participation in workplace wellness programs. Focus group discussions were transcribed and coded to identify main themes related to healthy eating, physical activity, and workplace factors that affect health. Results Although the union informants recognized the need for workplace wellness programs, very few programs were offered because informants did not know how to reach their widespread and diverse membership. Informants from the health care organization described various programs available to employees but noted several barriers to effective implementation. Workers discussed how their job characteristics contributed to their weight; irregular schedules, shift work, short breaks, physical job demands, and food options at work were among the most commonly discussed contributors to poor eating and exercise behaviors. Workers also described several general factors such as motivation, time, money, and conflicting responsibilities. Conclusion The workplace offers unique opportunities for obesity interventions that go beyond traditional approaches. Our results suggest that modifying the physical and social work environment by using participatory or integrated health and safety approaches may improve eating and physical activity behaviors. However, more research is needed about the methods best suited to the needs of low-wage workers. PMID:25950574

Transient and local increase in the permeability of the blood-brain barrier and the blood-retinal barrier by hyperthermia of magnetic nanoparticles in a rat model

NASA Astrophysics Data System (ADS)

Tabatabaei Shafie, Seyed Nasrollah

After successfully propelling therapeutic agents encapsulated in magnetic micro-carriers to a specific location inside an animal model by the gradient magnetic field of a modified clinical Magnetic Resonance (MR) scanner, we are now aiming to perform local drug delivery in the region of the central nervous system (CNS). To achieve localized drug delivery and increase efficacy, this project advances the theme that the therapeutic agents must be administered by means no more invasive than an intravenous injection followed by remote propulsion, controlled tracking, and on-command actuation in the CNS. The demanding function of the CNS requires an extremely stable environment. In fact, any small change in the composition of the interstitial fluid in the CNS plays a predominant role in regulating its microenvironment and neuronal activity. Therefore, the CNS is conceived to protect itself from frequent fluctuations of extracellular concentration of hormones, amino acids, and ion levels that occur after meals, exercise, or stress - as well as from toxic pathogens that may be circulating in the blood stream. This preventive barrier consists mainly of tightly interconnected endothelial cells that carpet the inner surface of most blood vessels in the CNS. While it provides a stable neuronal environment, more than 98% of all drug molecules are not able to cross this barrier and the extent to which a molecule enters is determined only by the permeability characteristics of the barrier. Therefore, while pharmaceutical research progresses for drug delivery to the CNS, it is limited by its pharmacokinetics through physiological barriers. Successful transient and local opening of the barrier for diffusion of therapeutics could strongly support the feasibility of treating a variety of neurological disorders. A recent effort presented in this dissertation provides evidence for the emergence of a novel approach to overcome this problem. This technique uses magnetic nanoparticles (MNPs) in conjunction with an alternating magnetic field to transiently increase barrier permeability for drug delivery. MNPs can act as miniaturized heat sources that, when under the influence of the alternating magnetic field, dissipate thermal energy directly and exclusively to the barrier (hyperthermia). In addition to its novelty, the findings confirm that the technique does not damage the neurovascular unit, i.e. neurons, astrocytes, etc. This in vivo investigation provides evidence that the proposed approach goes beyond former methods to access the CNS tissue with higher spatial precision, advanced control and apparent absence of immune reaction. Evidently, the ensemble of tracking and displacement abilities (MR technology), as well as hyperthermia, makes MNPs a principal component of the proposed non-invasive targeted drug delivery mechanism to the CNS. Because of its simplicity and specificity, this technique can introduce an enormous economical and social impact on quality of the life of patients diagnosed with CNS-related disorders.

Chaotic neoclassical separatrix dissipation in parametric drift-wave decay.

PubMed

Kabantsev, A A; Tsidulko, Yu A; Driscoll, C F

2014-02-07

Experiments and theory characterize a parametric decay instability between plasma drift waves when the nonlinear coupling is modified by an electrostatic barrier. Novel mode coupling terms representing enhanced dissipation and mode phase shifts are caused by chaotic separatrix crossings on the wave-ruffled separatrix. Experimental determination of these coupling terms is in broad agreement with new chaotic neoclassical transport analyses.

78 FR 57418 - Compliance With Order EA-13-109, Order Modifying Licenses With Regard to Reliable Hardened...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-18

... in development of the implementing guidance. The events at the Fukushima Dai-ichi nuclear power plant... public should a release occur. At Fukushima Dai-ichi, limitations in time and unpredictable conditions... containments) of three of the Fukushima Dai-ichi units. The loss of the various barriers led to the release of...

Using Participatory Action Research to Develop a School-Based Environmental Intervention to Support Healthy Eating and Physical Activity

ERIC Educational Resources Information Center

Vecchiarelli, Stephanie; Prelip, Michael; Slusser, Wendelin; Weightman, Heather; Neumann, Charlotte

2005-01-01

Rates of overweight children and adolescents have nearly tripled over the past 30 years. Many barriers exist to healthy eating and physical activity for children and adolescents, including factors in the school and community environment. It is these modifiable school environmental factors that led to the development of the Nutrition Friendly…

Sociodemographic Barriers to Early Detection of Autism: Screening and Evaluation Using the M-CHAT, M-CHAT-R, and Follow-Up

ERIC Educational Resources Information Center

Khowaja, Meena K.; Hazzard, Ann P.; Robins, Diana L.

2015-01-01

Parents (n = 11,845) completed the Modified Checklist for Autism in Toddlers (or its latest revision) at pediatric visits. Using sociodemographic predictors of maternal education and race, binary logistic regressions were utilized to examine differences in autism screening, diagnostic evaluation participation rates and outcomes, and reasons for…

On the enhanced sampling over energy barriers in molecular dynamics simulations.

PubMed

Gao, Yi Qin; Yang, Lijiang

2006-09-21

We present here calculations of free energies of multidimensional systems using an efficient sampling method. The method uses a transformed potential energy surface, which allows an efficient sampling of both low and high energy spaces and accelerates transitions over barriers. It allows efficient sampling of the configuration space over and only over the desired energy range(s). It does not require predetermined or selected reaction coordinate(s). We apply this method to study the dynamics of slow barrier crossing processes in a disaccharide and a dipeptide system.

YIP Formal Synthesis of Software-Based Control Protocols for Fractionated,Composable Autonomous Systems

DTIC Science & Technology

2016-07-08

Systems Using Automata Theory and Barrier Certifi- cates We developed a sound but incomplete method for the computational verification of specifications...method merges ideas from automata -based model checking with those from control theory including so-called barrier certificates and optimization-based... Automata theory meets barrier certificates: Temporal logic verification of nonlinear systems,” IEEE Transactions on Automatic Control, 2015. [J2] R

A Novel 1,4-Dihydropyridine Derivative Improves Spatial Learning and Memory and Modifies Brain Protein Expression in Wild Type and Transgenic APPSweDI Mice.

PubMed

Jansone, Baiba; Kadish, Inga; van Groen, Thomas; Beitnere, Ulrika; Moore, Doyle Ray; Plotniece, Aiva; Pajuste, Karlis; Klusa, Vija

2015-01-01

Ca2+ blockers, particularly those capable of crossing the blood-brain barrier (BBB), have been suggested as a possible treatment or disease modifying agents for neurodegenerative disorders, e.g., Alzheimer's disease. The present study investigated the effects of a novel 4-(N-dodecyl) pyridinium group-containing 1,4-dihydropyridine derivative (AP-12) on cognition and synaptic protein expression in the brain. Treatment of AP-12 was investigated in wild type C57BL/6J mice and transgenic Alzheimer's disease model mice (Tg APPSweDI) using behavioral tests and immunohistochemistry, as well as mass spectrometry to assess the blood-brain barrier (BBB) penetration. The data demonstrated the ability of AP-12 to cross the BBB, improve spatial learning and memory in both mice strains, induce anxiolytic action in transgenic mice, and increase expression of hippocampal and cortical proteins (GAD67, Homer-1) related to synaptic plasticity. The compound AP-12 can be seen as a prototype molecule for use in the design of novel drugs useful to halt progression of clinical symptoms (more specifically, anxiety and decline in memory) of neurodegenerative diseases, particularly Alzheimer's disease.

Synergistic tumor microenvironment targeting and blood-brain barrier penetration via a pH-responsive dual-ligand strategy for enhanced breast cancer and brain metastasis therapy.

PubMed

Li, Man; Shi, Kairong; Tang, Xian; Wei, Jiaojie; Cun, Xingli; Long, Yang; Zhang, Zhirong; He, Qin

2018-05-22

Cancer associated fibroblasts (CAFs) which shape the tumor microenvironment (TME) and the presence of blood brain barrier (BBB) remain great challenges in targeting breast cancer and its brain metastasis. Herein, we reported a strategy using PTX-loaded liposome co-modified with acid-cleavable folic acid (FA) and BBB transmigrating cell penetrating peptide dNP2 peptide (cFd-Lip/PTX) for enhanced delivery to orthotopic breast cancer and its brain metastasis. Compared with single ligand or non-cleavable Fd modified liposomes, cFd-Lip exhibited synergistic TME targeting and BBB transmigration. Moreover, upon arrival at the TME, the acid-cleavable cFd-Lip/PTX showed sensitive cleavage of FA, which reduced the hindrance effect and maximized the function of both FA and dNP2 peptide. Consequently, efficient targeting of folate receptor (FR)-positive tumor cells and FR-negative CAFs was achieved, leading to enhanced anti-tumor activity. This strategy provides a feasible approach to the cascade targeting of TME and BBB transmigration in orthotopic and metastatic cancer treatment. Copyright © 2018. Published by Elsevier Inc.

Evidence-based psychological treatments for mental disorders: Modifiable barriers to access and possible solutions

PubMed Central

Harvey, Allison G.; Gumport, Nicole B.

2015-01-01

The prevalence of mental disorders is high and appears to be growing, yet the majority of individuals who meet diagnostic criteria for a mental disorder are not able to access an adequate treatment. While evidence-based psychological treatments (EBPTs) are effective single or adjunctive treatments for mental disorders, there is also evidence that access to these treatments is diminishing. We seek to highlight modifiable barriers to these problems at the patient, therapist, treatment, organization and government-levels of analysis. A range of solutions to each set of contributors is offered and domains for future research are highlighted. In particular, we focus on the need to continue to work toward innovation in treatment development while also solving the difficulties relating to the dissemination of EBPTs. Several relatively new concepts in the field will be discussed (implementation cliff, program drift, voltage drop and deployment treatment development) and we contrast America and England as examples of government-level processes that are in the process of major change with respect to EBPTs. We conclude that there is a need for people in our field to become more knowledgeable about, and get involved in, shaping public policy. PMID:25768982

Barrier modification in sub-barrier fusion reaction 64Ni+100Mo using Wong formula with Skyrme forces in semiclassical formalism

NASA Astrophysics Data System (ADS)

Kumar, Raj; Gupta, Raj K.

2011-09-01

We obtain the nuclear proximity potential by using semiclassical extended Thomas Fermi (ETF) approach in Skyrme energy density formalism (SEDF), and use it in the extended l-summed Wong formula under frozen density approximation. This method has the advantage of allowing the use of different Skyrme forces, giving different barriers. Thus, for a given reaction, we could choose a Skyrme force with proper barrier characteristics, not-requiring extra "barrier lowering" or "barrier narrowing" for a best fit to data. For the 64Ni+100Mo reaction, the l-summed Wong formula, with effects of deformations and orientations of nuclei included, fits the fusion-evaporation cross section data exactly for the force GSkI, requiring additional barrier modifications for forces SIII and SV. However, the same for other similar reactions, like 58,64Ni+58,64Ni, fit the data best for SIII force. Hence, the barrier modification effects in l-summed Wong expression depend on the choice of Skyrme force in semiclassical ETF method.

Comparison of Methodologies of Activation Barrier Measurements for Reactions with Deactivation

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

Xie, Zhenhua; Yan, Binhang; Zhang, Li

In this work, methodologies of activation barrier measurements for reactions with deactivation were theoretically analyzed. Reforming of ethane with CO 2 was introduced as an example for reactions with deactivation to experimentally evaluate these methodologies. Both the theoretical and experimental results showed that due to catalyst deactivation, the conventional method would inevitably lead to a much lower activation barrier, compared to the intrinsic value, even though heat and mass transport limitations were excluded. In this work, an optimal method was identified in order to provide a reliable and efficient activation barrier measurement for reactions with deactivation.

Comparison of Methodologies of Activation Barrier Measurements for Reactions with Deactivation

DOE PAGES

Xie, Zhenhua; Yan, Binhang; Zhang, Li; ...

2017-01-25

In this work, methodologies of activation barrier measurements for reactions with deactivation were theoretically analyzed. Reforming of ethane with CO 2 was introduced as an example for reactions with deactivation to experimentally evaluate these methodologies. Both the theoretical and experimental results showed that due to catalyst deactivation, the conventional method would inevitably lead to a much lower activation barrier, compared to the intrinsic value, even though heat and mass transport limitations were excluded. In this work, an optimal method was identified in order to provide a reliable and efficient activation barrier measurement for reactions with deactivation.

In situ formation of phosphate barriers in soil

DOEpatents

Moore, Robert C.

2002-01-01

Reactive barriers and methods for making reactive barriers in situ in soil for sequestering soil ontaminants including actinides and heavy metals. The barrier includes phosphate, and techniques are disclosed for forming specifically apatite barriers. The method includes injecting dilute reagents into soil in proximity to a contamination plume or source such as a waste drum to achieve complete or partial encapsulation of the waste. Controlled temperature and pH facilitates rapid formation of apatite, for example, where dilute aqueous calcium chloride and dilute aqueous sodium phosphate are the selected reagents. Mixing of reagents to form precipitate is mediated and enhanced through movement of reagents in soil as a result of phenomena including capillary action, movement of groundwater, soil washing and reagent injection pressure.

Method Producing an SNS Superconducting Junction with Weak Link Barrier

NASA Technical Reports Server (NTRS)

Hunt, Brian D. (Inventor)

1999-01-01

A method of producing a high temperature superconductor Josephson element and an improved SNS weak link barrier element is provided. A YBaCuO superconducting electrode film is deposited on a substrate at a temperature of approximately 800 C. A weak link barrier layer of a nonsuperconducting film of N-YBaCuO is deposited over the electrode at a temperature range of 520 C. to 540 C. at a lower deposition rate. Subsequently a superconducting counter-electrode film layer of YBaCuO is deposited over the weak link barrier layer at approximately 800 C. The weak link barrier layer has a thickness of approximately 50 A and the SNS element can be constructed to provide an edge geometry junction.

Resonances for Symmetric Two-Barrier Potentials

ERIC Educational Resources Information Center

Fernandez, Francisco M.

2011-01-01

We describe a method for the accurate calculation of bound-state and resonance energies for one-dimensional potentials. We calculate the shape resonances for symmetric two-barrier potentials and compare them with those coming from the Siegert approximation, the complex scaling method and the box-stabilization method. A comparison of the…

Material Barriers to Diffusive Mixing

NASA Astrophysics Data System (ADS)

Haller, George; Karrasch, Daniel

2017-11-01

Transport barriers, as zero-flux surfaces, are ill-defined in purely advective mixing in which the flux of any passive scalar is zero through all material surfaces. For this reason, Lagrangian Coherent Structures (LCSs) have been argued to play the role of mixing barriers as most repelling, attracting or shearing material lines. These three kinematic concepts, however, can also be defined in different ways, both within rigorous mathematical treatments and within the realm of heuristic diagnostics. This has lead to a an ever-growing number of different LCS methods, each generally identifying different objects as transport barriers. In this talk, we examine which of these methods have actual relevance for diffusive transport barriers. The latter barriers are arguably the practically relevant inhibitors in the mixing of physically relevant tracers, such as temperature, salinity, vorticity or potential vorticity. We demonstrate the role of the most effective diffusion barriers in analytical examples and observational data. Supported in part by the DFG Priority Program on Turbulent Superstructures.

The Employers' perspective on barriers and facilitators to employment of people with intellectual disability: A differential mixed-method approach.

PubMed

Kocman, Andreas; Fischer, Linda; Weber, Germain

2018-01-01

Obtaining employment is among the most important ambitions of people with intellectual disability. Progress towards comprehensive inclusive employment is hampered by numerous barriers. Limited research is available on these barriers and strategies to overcome them. A mixed method approach in a sample of 30 HR-managers was used to assess (i) differences in perceived barriers for employment of people with specific disabilities and mental disorders; (ii) barriers specific to employing people with intellectual disability; (iii) strategies to overcome these barriers. Employers perceive more barriers for hiring people with intellectual disability and mental disorders than for physical disabilities. Employment for this population is hampered by a perceived lack of skills and legal issues. Strategies perceived as beneficial are supplying information, changes in organizational strategies and legal changes. Employers' differentiated expectations and reservations towards hiring individuals with specific disabilities need to be taken into account to increase employment for people with intellectual disability. © 2017 John Wiley & Sons Ltd.

Impact of satisfaction, nurse-patient interactions and perceived benefits on health behaviors following a cardiac event.

PubMed

Zrinyi, Miklos; Horvath, Teodora

2003-07-01

To describe patient perceptions of quality and satisfaction with nursing care, nurse-patient interactions and barriers to and benefits of implementing a healthy lifestyle. A pretest-posttest cross-sectional correlational research design was used. Subjects were randomly selected between November 2001 and January 2002 from patients admitted to the National Institute of Cardiology in Budapest, Hungary. Participants completed 3 self-reported measures and a demographic survey, which assessed individual lifestyle behaviors (e.g. frequency of smoking, physical activity, stress and unhealthy dieting). Satisfaction with nursing care and nurse-patient interactions influenced both perceived benefits and barriers. Patient satisfaction and perceived benefits at discharge were associated with more frequent exercising and less smoking. Among other factors, perceived benefits at discharge were predicted by attentive nurse behaviors toward patients and by patients' ability to initiate discussion with nurses. Findings support effects of patient satisfaction and nurse-patient relationships on perceived benefits/barriers. Compared to barriers, perceived benefits more importantly determined health behaviors. Attentive nursing care and the patient's ability to discuss health concerns with nurses appear more influential in modifying patient perceptions. Exploring nursing interventions to maximize perceived benefits during hospitalization is suggested.

Control of ITBs in Magnetically Confined Burning Plasmas

NASA Astrophysics Data System (ADS)

Panta, S. R.; Newman, D. E.; Terry, P. W.; Sanchez, R.

2017-10-01

In the magnetically confined burning plasma devices (in this case Tokamaks), internal transport barriers (ITBs) are those regimes in which the turbulence is suppressed by the E X B velocity shear, reducing the turbulent transport. This often occurs at a critical gradient in the profiles. The change in the transport then modifies the density and temperature profiles feeding back on the system. These transport barriers have to be controlled both to form them for improved confinement and remove them to both prevent global instabilities and to remove the ash and unnecessary impurities in the device. In this work we focus on pellet injection and modulated RF heating as a way to trigger and control the ITBs. These have an immediate consequence on density and temperature and hence pressure profiles acting as a control knob. For example, depending upon pellet size and its radial position of injection, it either helps to form or strengthen the barrier or to get rid of ITBs in the different transport channels of the burning plasmas. This transport model is then used to investigate the control and dynamics of the transport barriers in burning plasmas using pellets and RF addition to the NBI power and alpha power.

Exploring the facilitators and barriers to engagement in physical activity for people with multiple sclerosis.

PubMed

Kayes, Nicola M; McPherson, Kathryn M; Schluter, Philip; Taylor, Denise; Leete, Marta; Kolt, Gregory S

2011-01-01

To explore the relationship that cognitive behavioural and other previously identified variables have with physical activity engagement in people with multiple sclerosis (MS). This study adopted a cross-sectional questionnaire design. Participants were 282 individuals with MS. Outcome measures included the Physical Activity Disability Survey--Revised, Cognitive and Behavioural Responses to Symptoms Questionnaire, Barriers to Health Promoting Activities for Disabled Persons Scale, Multiple Sclerosis Self-efficacy Scale, Self-Efficacy for Chronic Diseases Scales and Chalder Fatigue Questionnaire. Multivariable stepwise regression analyses found that greater self-efficacy, greater reported mental fatigue and lower number of perceived barriers to physical activity accounted for a significant proportion of variance in physical activity behaviour, over that accounted for by illness-related variables. Although fear-avoidance beliefs accounted for a significant proportion of variance in the initial analyses, its effect was explained by other factors in the final multivariable analyses. Self-efficacy, mental fatigue and perceived barriers to physical activity are potentially modifiable variables which could be incorporated into interventions designed to improve physical activity engagement. Future research should explore whether a measurement tool tailored to capture beliefs about physical activity identified by people with MS would better predict participation in physical activity.

Using the WHO Surgical Safety Checklist to Direct Perioperative Quality Improvement at a Surgical Hospital in Cambodia: The Importance of Objective Confirmation of Process Completion.

PubMed

Garland, Naomi Y; Kheng, Sokhavatey; De Leon, Michael; Eap, Hourt; Forrester, Jared A; Hay, Janice; Oum, Palritha; Sam Ath, Socheat; Stock, Simon; Yem, Samprathna; Lucas, Gerlinda; Weiser, Thomas G

2017-12-01

The WHO surgical safety checklist (SSC) is known to prevent postoperative complications; however, strategies for effective implementation are unclear. In addition to cultural and organizational barriers faced by high-income countries, resource-constrained settings face scarcity of durable and consumable goods. We used the SSC to better understand barriers to improvement at a trauma hospital in Battambang, Cambodia. We introduced the SSC and trained data collectors to observe surgical staff performing the checklist. Members of the research team observed cases and data collection. After 3 months, we modified the data collection tool to focus on infection prevention and elicit more accurate responses. Over 16 months we recorded data on 695 operations (304 cases using the first tool and 391 cases with the modified tool). The first tool identified five items as being in high compliance, which were then excluded from further assessment. Two items-instrument sterility confirmation and sponge counting-were identified as being misinterpreted by the data collectors' tool. These items were reworded to capture objective assessment of task completion. Confirmation of instrument sterility was initially never performed but rectified to >95% compliance; sponge counting and prophylactic antibiotic administration were consistently underperformed. Staff complied with communication elements of the SSC and quickly adopted process improvements. The wording of our data collection tool affected interpretation of compliance with standards. Material resources are not the primary barrier to checklist implementation in this setting, and future work should focus on clarification of protocols and objective confirmation of tasks.

Nanosized insulin-complexes based on biodegradable amine-modified graft polyesters poly[vinyl-3-(diethylamino)-propylcarbamate-co-(vinyl acetate)-co-(vinyl alcohol)]-graft-poly(L-lactic acid): protection against enzymatic degradation, interaction with Caco-2 cell monolayers, peptide transport and cytotoxicity.

PubMed

Simon, Michael; Behrens, Isabel; Dailey, Lea Anne; Wittmar, Matthias; Kissel, Thomas

2007-05-01

Non-parenteral insulin delivery by the oral route is limited by epithelial barriers and enzymatic degradation. Nanosized insulin-complexes based on amine modified comb-like polyesters were designed to overcome these barriers. Protection of insulin in nanocomplexes (NC) from enzymatic degradation was investigated. The interaction with enterocyte-like Caco-2 cells in terms of cytotoxicity, transport through and uptake in the cell layers was evaluated by measuring transepithelial electrical resistance (TEER), release of lactate dehydrogenase (LDH) and insulin transport. The protection capacity of NC and their interaction with Caco-2 cells varied strongly as a function of lactide-grafting (hydrophobicity). With increasing lactide-grafting (P(26) < or = P(26)-1(LL) < or = P(26)-2(LL)) NC protected up to 95% of the insulin against degradation by trypsin. Transport and uptake into cell monolayers increased with higher l-lactid grafting. About 25% of a 1.25mg/ml TRITC-insulin NC dispersion with P(26)-2(LL) was recovered in Caco-2 cells after 90 min. A concentration dependent cytotoxicity profile was observed showing elevated LDH release and decreased TEER values. The cytotoxicity correlates with the surfactant like character of the polymers, decreasing the surface tension to 46 mN/m for the amphiphilic P(26)-2(LL). The observed TEER decrease was reversible after 20 h, suggesting that the biodegradable comb-polyesters offer a promising approach to overcome mucosal barriers.

Puncture detecting barrier materials

DOEpatents

Hermes, R.E.; Ramsey, D.R.; Stampfer, J.F.; Macdonald, J.M.

1998-03-31

A method and apparatus for continuous real-time monitoring of the integrity of protective barrier materials, particularly protective barriers against toxic, radioactive and biologically hazardous materials has been developed. Conductivity, resistivity or capacitance between conductive layers in the multilayer protective materials is measured by using leads connected to electrically conductive layers in the protective barrier material. The measured conductivity, resistivity or capacitance significantly changes upon a physical breach of the protective barrier material. 4 figs.

Puncture detecting barrier materials

DOEpatents

Hermes, Robert E.; Ramsey, David R.; Stampfer, Joseph F.; Macdonald, John M.

1998-01-01

A method and apparatus for continuous real-time monitoring of the integrity of protective barrier materials, particularly protective barriers against toxic, radioactive and biologically hazardous materials has been developed. Conductivity, resistivity or capacitance between conductive layers in the multilayer protective materials is measured by using leads connected to electrically conductive layers in the protective barrier material. The measured conductivity, resistivity or capacitance significantly changes upon a physical breach of the protective barrier material.

An integral equation method for calculating sound field diffracted by a rigid barrier on an impedance ground.

PubMed

Zhao, Sipei; Qiu, Xiaojun; Cheng, Jianchun

2015-09-01

This paper proposes a different method for calculating a sound field diffracted by a rigid barrier based on the integral equation method, where a virtual boundary is assumed above the rigid barrier to divide the whole space into two subspaces. Based on the Kirchhoff-Helmholtz equation, the sound field in each subspace is determined with the source inside and the boundary conditions on the surface, and then the diffracted sound field is obtained by using the continuation conditions on the virtual boundary. Simulations are carried out to verify the feasibility of the proposed method. Compared to the MacDonald method and other existing methods, the proposed method is a rigorous solution for whole space and is also much easier to understand.

A sediment record of barrier estuary behaviour at the mesoscale: Interpreting high-resolution particle size analysis

NASA Astrophysics Data System (ADS)

Clarke, David W.; Boyle, John F.; Chiverrell, Richard C.; Lario, Javier; Plater, Andrew J.

2014-09-01

At present, limited understanding of mesoscale (years-decades-centuries) back-barrier lagoon, barrier estuary behaviour is a critical shortcoming for resource managers and decision makers. In this paper, high-resolution particle size analysis of a sediment core from an intermittently open and closed barrier estuary is utilised to reconstruct a history of back-barrier environmental change at mesoscale temporal resolution. Sediments from Pescadero Marsh, California, were analysed for their particle size distribution at consecutive 2-mm intervals down-core. Site selection, informed by a time series of maps and aerial photographs coupled with a robust core chronology, ensured that the particle size data primarily reflect changing hydrodynamics of the back-barrier area over the European-American era (1850 to the present). Following more traditional plotting of particle size data and summary statistics, and statistical analysis of particle size end-members, visual analysis and categorisation of particle size distribution curves (PSDCs) provide an effective basis for the identification of recurring modal sizes and subpopulations. These particle size windows (PSWs) are interpreted as reflecting different modes of sediment transport and deposition, i.e., suspension and saltation loads, the varying prominence of which is interpreted as being modified by barrier integrity. When considered together, the down-core mean particle size (MPS) trend and individual PSDCs offer considerable insight into mesoscale system behaviour at subannual resolution over multiple years. This behaviour is expressed in the recurrence of characteristic barrier estuarine environments (closed lagoon, tidal lagoon, tidal marsh, and open estuary) and the overall barrier regime, and their persistence over the last c. 150 years. Subannual and multiannual fluctuations in back-barrier environmental configuration are seen to be superimposed on a longer-term quasi-stable barrier regime, demonstrating the value of the applied methodology with regard to bridging the estuarine evolution (long-term, stratigraphic) and process (short-term, geomorphic) knowledge bases. The documented behaviour suggests a level of innate morphological resilience in the system over the long term despite episodic disturbance by high-energy storms. Such empirical demonstrations of resilient behaviour in coastal environments are rare at the mesoscale.

Multi-layer light-weight protective coating and method for application

NASA Technical Reports Server (NTRS)

Wiedemann, Karl E. (Inventor); Clark, Ronald K. (Inventor); Taylor, Patrick J. (Inventor)

1992-01-01

A thin, light-weight, multi-layer coating is provided for protecting metals and their alloys from environmental attack at high temperatures. A reaction barrier is applied to the metal substrate and a diffusion barrier is then applied to the reaction barrier. A sealant layer may also be applied to the diffusion barrier if desired. The reaction barrier is either non-reactive or passivating with respect to the metal substrate and the diffusion barrier. The diffusion barrier is either non-reactive or passivating with respect to the reaction barrier and the sealant layer. The sealant layer is immiscible with the diffusion barrier and has a softening point below the expected use temperature of the metal.

Influence of temperature on Al/p-CuInAlSe2 thin-film Schottky diodes

NASA Astrophysics Data System (ADS)

Parihar, Usha; Ray, Jaymin; Panchal, C. J.; Padha, Naresh

2016-06-01

Al/p-CuInAlSe2 Schottky diodes were fabricated using the optimized thin layers of CuInAlSe2 semiconductor. These diodes were used to study their temperature-dependent current-voltage (I-V) and capacitance-voltage (C-V) analysis over a wide range of 233-353 K. Based on these measurements, diode parameters such as ideality factor ( η), barrier height (ϕbo) and series resistance ( R s) were determined from the downward curvature of I-V characteristics using Cheung and Cheung method. The extracted parameters were found to be strongly temperature dependent; ϕbo increases, while η and R s decrease with increasing temperature. This behavior of ϕbo and η with change in temperature has been explained on the basis of barrier inhomogeneities over the MS interface by assuming a Gaussian distribution (GD) of the ϕbo at the interface. GD of barrier height (BH) was confirmed from apparent BH (ϕap) versus q/2 kT plot, and the values of the mean BH and standard deviation (σs) obtained from this plot at zero bias were found to be 1.02 and 0.14 eV, respectively. Also, a modified ln ( {J_{{s}} /T2 } ) - q2 σ_{{s}}2 /2k2 T2 versus q/ kT plot for Al/p-CuInAlSe2 Schottky diodes according to the GD gives ϕbo and Richardson constant ( A ** ) as 1.01 eV and 26 Acm-2 K-2, respectively. The Richardson constant value of 26 Acm-2 K-2 is very close to the theoretical value of 30 Acm-2 K-2. The discrepancy between BHs obtained from I-V and C-V measurements has also been interpreted.

Progressive multiple sclerosis: from pathogenic mechanisms to treatment.

PubMed

Correale, Jorge; Gaitán, María I; Ysrraelit, María C; Fiol, Marcela P

2017-03-01

During the past decades, better understanding of relapsing-remitting multiple sclerosis disease mechanisms have led to the development of several disease-modifying therapies, reducing relapse rates and severity, through immune system modulation or suppression. In contrast, current therapeutic options for progressive multiple sclerosis remain comparatively disappointing and challenging. One possible explanation is a lack of understanding of pathogenic mechanisms driving progressive multiple sclerosis. Furthermore, diagnosis is usually retrospective, based on history of gradual neurological worsening with or without occasional relapses, minor remissions or plateaus. In addition, imaging methods as well as biomarkers are not well established. Magnetic resonance imaging studies in progressive multiple sclerosis show decreased blood-brain barrier permeability, probably reflecting compartmentalization of inflammation behind a relatively intact blood-brain barrier. Interestingly, a spectrum of inflammatory cell types infiltrates the leptomeninges during subpial cortical demyelination. Indeed, recent magnetic resonance imaging studies show leptomeningeal contrast enhancement in subjects with progressive multiple sclerosis, possibly representing an in vivo marker of inflammation associated to subpial demyelination. Treatments for progressive disease depend on underlying mechanisms causing central nervous system damage. Immunity sheltered behind an intact blood-brain barrier, energy failure, and membrane channel dysfunction may be key processes in progressive disease. Interfering with these mechanisms may provide neuroprotection and prevent disability progression, while potentially restoring activity and conduction along damaged axons by repairing myelin. Although most previous clinical trials in progressive multiple sclerosis have yielded disappointing results, important lessons have been learnt, improving the design of novel ones. This review discusses mechanisms involved in progressive multiple sclerosis, correlations between histopathology and magnetic resonance imaging studies, along with possible new therapeutic approaches. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Employment prospects and trends for gastroenterology trainees in Canada: A nationwide survey

PubMed Central

Razik, Roshan; Cino, Maria; Nguyen, Geoffrey C

2013-01-01

BACKGROUND: Many gastroenterology (GI) trainees face a variety of barriers to stable employment and are finding it increasingly difficult to secure employment in their chosen field. OBJECTIVE: To elucidate factors that contribute to the burden of unemployment and underemployment, and to examine solutions that may remedy this growing problem in the field of GI. METHODS: A nationwide survey of current, incoming and recently graduated individuals of GI training programs in Canada was conducted. Trainees in pediatric GI programs and those enrolled in sub-specialty programs within GI were also included. RESULTS: The response rate was 62%, with 93% of respondents enrolled in an adult GI training program. Many (73%) respondents planned to pursue further subspecialty training and the majority (53%) reported concerns regarding job security after graduation as contributory factors. Only 35% of respondents were confident that they would secure employment within six months of completing their training. Regarding barriers to employment, the most cited perceived reasons were lack of funding (both from hospitals and provincial governments) and senior physicians who continue to practice beyond retirement years. Sixty-nine per cent perceived a greater need for career guidance and 49% believed there were too many GI trainees relative to the current job market in their area. Most residents had a contingency plan if they remained unemployed >18 months, which often included moving to another province or to the United States. CONCLUSION: GI trainees throughout Canada reported substantial concerns about securing employment, citing national retirement trends and lack of funding as primary barriers to employment. Although these issues are not easily modifiable, certain problems should be targeted including optimizing training quotas, tailoring career guidance to the needs of the population, and emphasizing credentialing and quality control in endoscopy. PMID:24199210

Synthesizing qualitative and quantitative evidence on non-financial access barriers: implications for assessment at the district level.

PubMed

O'Connell, Thomas S; Bedford, K Juliet A; Thiede, Michael; McIntyre, Di

2015-06-09

A key element of the global drive to universal health coverage is ensuring access to needed health services for everyone, and to pursue this goal in an equitable way. This requires concerted efforts to reduce disparities in access through understanding and acting on barriers facing communities with the lowest utilisation levels. Financial barriers dominate the empirical literature on health service access. Unless the full range of access barriers are investigated, efforts to promote equitable access to health care are unlikely to succeed. This paper therefore focuses on exploring the nature and extent of non-financial access barriers. We draw upon two structured literature reviews on barriers to access and utilization of maternal, newborn and child health services in Ghana, Bangladesh, Vietnam and Rwanda. One review analyses access barriers identified in published literature using qualitative research methods; the other in published literature using quantitative analysis of household survey data. We then synthesised the key qualitative and quantitative findings through a conjoint iterative analysis. Five dominant themes on non-financial access barriers were identified: ethnicity; religion; physical accessibility; decision-making, gender and autonomy; and knowledge, information and education. The analysis highlighted that non-financial factors pose considerable barriers to access, many of which relate to the acceptability dimension of access and are challenging to address. Another key finding is that quantitative research methods, while yielding important findings, are inadequate for understanding non-financial access barriers in sufficient detail to develop effective responses. Qualitative research is critical in filling this gap. The analysis also indicates that the nature of non-financial access barriers vary considerably, not only between countries but also between different communities within individual countries. To adequately understand access barriers as a basis for developing effective strategies to address them, mixed-methods approaches are required. From an equity perspective, communities with the lowest utilisation levels should be prioritised and the access barriers specific to that community identified. It is, therefore, critical to develop approaches that can be used at the district level to diagnose and act upon access barriers if we are to pursue an equitable path to universal health coverage.

Next Steps for Science and Policy on Promoting Vegetable Consumption among US Infants and Young Children12

PubMed Central

Fisher, Jennifer O; Dwyer, Johanna T

2016-01-01

Vegetables are an important part of a healthy diet for infants and young children, but they are poorly accepted and underconsumed. This paper highlights major themes and research needs for understanding how to raise children to consume and enjoy vegetables as part of a healthful diet. A range of factors impedes US infants and young children from eating as many vegetables as experts consider optimal for child nutrition, health, and development. Barriers include biological and behavioral issues relating to infant and child development, household- and family-related barriers, obstacles in the larger community, economic limitations, and some government policies and programs. These barriers must be removed to encourage children to eat more vegetables. Research gaps also must be filled. We summarize the basic and applied research that is needed to craft more effective messages, devise strategies for parents and other child caretakers to take within households, develop action in the larger community, and modify some government policies and programs. PMID:26773035

Runge-Lenz wave packet in multichannel Stark photoionization

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

Texier, F.

2005-01-01

In a previous slow photoionization experiment, modulations of ionization rings were manifested for Xe in a constant electric field. The present quantum calculation reveals that the modulation is an effect of the multichannel core scattering and of tunneling waves through the Coulomb-Stark potential barrier: the barrier reduces the number of oscillations that is observed relatively to the number of oscillations of the short range wave functions, and the nonhydrogenic core phase shifts modify the position of the ionization rings. We find a hidden difference, in the ionization process, for two close values of the energy depending on the resonance withmore » the barrier. The ionization intensity is interpreted as a Runge-Lenz wave packet; thus, we can relate the quantum modulation to the classical Coulomb-Stark trajectories. The Runge-Lenz wave packet differs from a usual temporal wave packet because its components are eigenstates of the Runge-Lenz vector z projection and its evolution is not temporal but spatial.« less

Next Steps for Science and Policy on Promoting Vegetable Consumption among US Infants and Young Children.

PubMed

Fisher, Jennifer O; Dwyer, Johanna T

2016-01-01

Vegetables are an important part of a healthy diet for infants and young children, but they are poorly accepted and underconsumed. This paper highlights major themes and research needs for understanding how to raise children to consume and enjoy vegetables as part of a healthful diet. A range of factors impedes US infants and young children from eating as many vegetables as experts consider optimal for child nutrition, health, and development. Barriers include biological and behavioral issues relating to infant and child development, household- and family-related barriers, obstacles in the larger community, economic limitations, and some government policies and programs. These barriers must be removed to encourage children to eat more vegetables. Research gaps also must be filled. We summarize the basic and applied research that is needed to craft more effective messages, devise strategies for parents and other child caretakers to take within households, develop action in the larger community, and modify some government policies and programs. © 2016 American Society for Nutrition.

The Coulomb based magneto-electric coupling in multiferroic tunnel junctions and granular multiferroics

NASA Astrophysics Data System (ADS)

Udalov, O. G.; Beloborodov, I. S.

2018-05-01

We study magneto-electric effect in two systems: i) multiferroic tunnel junction (MFTJ) - magnetic tunnel junction with ferroelectric barrier and ii) granular multiferroic (GMF) in which ferromagnetic (FM) metallic grains embedded into ferroelectric matrix. We show that the Coulomb interaction influences the magnetic state of the system in several ways: i) through the spin-dependent part of the Coulomb interaction; ii) due to the Coulomb blockade effect suppressing electron hopping and therefore reducing magnetic coupling; and iii) through image forces and polarization screening that modify the barrier for electrons in MFTJ and GMF. We show that in the absence of spin-orbit or strain-mediated coupling magneto-electric effect appears in GMF and MFTJ. The Coulomb interaction depends on the dielectric properties of the system. For GMF it depends on the dielectric constant of FE matrix and for MFTJ on the dielectric constant of the FE barrier. Applying external electric field one can tune the dielectric constant and the Coulomb interaction. Thus, one can control magnetic state with electric field.

Surface Modulation of Graphene Field Effect Transistors on Periodic Trench Structure.

PubMed

Jin, Jun Eon; Choi, Jun Hee; Yun, Hoyeol; Jang, Ho-Kyun; Lee, Byung Chul; Choi, Ajeong; Joo, Min-Kyu; Dettlaff-Weglikowska, Urszula; Roth, Siegmar; Lee, Sang Wook; Lee, Jae Woo; Kim, Gyu Tae

2016-07-20

In this work, graphene field effect transistors (FETs) were fabricated on a trench structure made by carbonized poly(methylmethacrylate) to modify the graphene surface. The trench-structured devices showed different characteristics depending on the channel orientation and the pitch size of the trenches as well as channel area in the FETs. Periodic corrugations and barriers of suspended graphene on the trench structure were measured by atomic force microscopy and electrostatic force microscopy. Regular barriers of 160 mV were observed for the trench structure with graphene. To confirm the transfer mechanism in the FETs depending on the channel orientation, the ratio of experimental mobility (3.6-3.74) was extracted from the current-voltage characteristics using equivalent circuit simulation. It is shown that the number of barriers increases as the pitch size decreases because the number of corrugations increases from different trench pitches. The noise for the 140 nm pitch trench is 1 order of magnitude higher than that for the 200 nm pitch trench.

A qualitative study examining the perceived barriers and facilitators to medical healthcare services among women with a serious mental illness.

PubMed

Borba, Christina P C; DePadilla, Lara; McCarty, Frances A; von Esenwein, Silke A; Druss, Benjamin G; Sterk, Claire E

2012-03-01

This qualitative study investigates the barriers and facilitators to accessing and utilizing healthcare services among women with a serious mental illness (SMI). A purposive sample of 30 poor, urban, predominantly African-American women with a diagnosis of an SMI was recruited. Interviews were audio-taped and transcribed verbatim. Data analysis was guided by a modified constant comparison approach. The findings highlight a variety of nonmedical factors that serve as both barriers and facilitators to accessing and utilizing medical healthcare services, such as a trusting relationship with a mental health provider and a women's social network. Nonmedical factors and personal circumstances seem to be important factors influencing pathways to healthcare services among women with an SMI. Efforts to better engage and retain women with an SMI into healthcare will need to better acknowledge and incorporate the larger social context of the women's lives. Copyright © 2012 Jacobs Institute of Women

Development of methods for skin barrier peeling tests.

PubMed

Omura, Yuko; Kazuharu, Seki; Kenji, Oishi

2006-01-01

We sought to develop a more effective method to evaluate the adhesive properties of skin barriers. The experimental design used was based on 3 principles: partial control, randomization, and repetition. Using these principles, the 180-degree peeling tests were conducted as specified in a standardized methodology (JIS Z0297) to the extent possible. However, the use of a stainless steel plate as a proxy for skin barrier application may result in the stretching and breaking of the skin barrier, making it impossible to obtain suitable measurements. Tests were conducted in constant temperature/ humidity chambers using a Tensilon Automatic Elongation Tester, where a sample was fixed on the side of a sample immobilization device, a sturdy metal (aluminum) box from which the air in the box was drawn off with a vacuum pump. A fluorocarbon polymer film was applied to the adhesive surface of a sample skin barrier. The film was peeled off in the volte-face (180-degree) direction in order to measure adhesive strengths. The films exhibit such properties as (a) ease of removal from the adhesive surface, (b) no resistance to a 180-degree fold back due to the thinness and flexibility of the material, and (c) tolerance of elongation. The adhesive properties of skin barriers were measured by peeling the fluorocarbon polymers in a 180-degree direction. Twelve specimen skin barrier products were selected for measurement, providing results with satisfactory reproducibility. Results based on the conventional stainless steel plate-based testing method acted as a control. The newly developed testing method enables chronological measurement results for skin barriers applied to fluorocarbon polymer films after 24 hours, 48 hours, and longer period.

Vented Cavity Radiant Barrier Assembly And Method

DOEpatents

Dinwoodie, Thomas L.; Jackaway, Adam D.

2000-05-16

A vented cavity radiant barrier assembly (2) includes a barrier (12), typically a PV module, having inner and outer surfaces (18, 22). A support assembly (14) is secured to the barrier and extends inwardly from the inner surface of the barrier to a building surface (14) creating a vented cavity (24) between the building surface and the barrier inner surface. A low emissivity element (20) is mounted at or between the building surface and the barrier inner surface. At least part of the cavity exit (30) is higher than the cavity entrance (28) to promote cooling air flow through the cavity.

Time and materials needed to survey, inject systemic fungicides, and install root-graft barriers for Dutch elm disease management

Treesearch

William N., Jr. Cannon; Jack H. Barger; Charles J. Kostichka; Charles J. Kostichka

1986-01-01

Dutch elm disease control practice in 15 communities showed a wide range of time and material required to apply control methods. The median time used for each method was: sanitation survey, 9.8 hours per square mile; symptom survey, 96 hours per thousand elms; systemic fungicide injection, 1.4 hours per elm; and root-graft barrier installation, 2.2 hours per barrier (5...

Gender differences in substance abuse treatment and barriers to care among persons with substance use disorders with and without comorbid major depression.

PubMed

Chen, Lian-Yu; Strain, Eric C; Crum, Rosa M; Mojtabai, Ramin

2013-01-01

To compare substance use disorders (SUD) treatment patterns and barriers to such treatment among men and women with SUD with and without comorbid major depressive episodes (MDE) in a community sample. Using data from adult participants in the National Survey on Drug Use and Health 2005-2010, we investigated differences by sex in the association of MDE comorbidity with SUD on patterns of, perceived unmet need for, and the perceived barriers to SUD treatments. Compared with participants with SUD without MDE, both men and women with comorbid SUD and MDE were more likely to use SUD services or to report an unmet need for such treatment. Sex modified the association of comorbidity and treatment patterns: males with MDE comorbidity had a greater likelihood of emergency room visits and use of inpatient services than females. Barriers to substance treatment were remarkably similar for males and females in both the SUD without MDE group and with MDE group, with attitudinal factors being the most common barriers. Comorbidity with MDE seems to be an important predictor of service utilization and perceived need for SUD treatment in both men and women. The association of comorbidity with the use of some types of services, however, seems to vary according to sex. The findings have implications for the design of sex-specific SUD treatment programs.

Influence of functional food components on gut health.

PubMed

Wan, Murphy L Y; Ling, K H; El-Nezami, Hani; Wang, M F

2018-01-30

Intestinal epithelial cells (IECs) lining the gastrointestinal tract establish a barrier between external environments and the internal milieu. An intact intestinal barrier maintains gut health and overall good health of the body by preventing from tissue injury, pathogen infection and disease development. When the intestinal barrier function is compromised, bacterial translocation can occur. Our gut microbiota also plays a fundamentally important role in health, for example, by maintaining intestinal barrier integrity, metabolism and modulating the immune system, etc. Any disruption of gut microbiota composition (also termed dysbiosis) can lead to various pathological conditions. In short, intestinal barrier and gut microbiota are two crucial factors affecting gut health. The gastrointestinal tract is a complex environment exposed to many dietary components and commensal bacteria. Dietary components are increasingly recognized to play various beneficial roles beyond basic nutrition, resulting in the development of the functional food concepts. Various dietary modifiers, including the consumption of live bacteria (probiotics) and ingestible food constituents such as prebiotics, as well as polyphenols or synbiotics (combinations of probiotics and prebiotics) are the most well characterized dietary bioactive compounds and have been demonstrated to beneficially impact the gut health and the overall well-being of the host. In this review we depict the roles of intestinal epithelium and gut microbiota in mucosal defence responses and the influence of certain functional food components on the modulation of gut health, with a particular focus on probiotics, prebiotics and polyphenols.

Analysis of Nanoporosity in Moisture Permeation Barrier Layers by Electrochemical Impedance Spectroscopy.

PubMed

Perrotta, Alberto; García, Santiago J; Michels, Jasper J; Andringa, Anne-Marije; Creatore, Mariadriana

2015-07-29

Water permeation in inorganic moisture permeation barriers occurs through macroscale defects/pinholes and nanopores, the latter with size approaching the water kinetic diameter (0.27 nm). Both permeation paths can be identified by the calcium test, i.e., a time-consuming and expensive optical method for determining the water vapor transmission rate (WVTR) through barrier layers. Recently, we have shown that ellipsometric porosimetry (i.e., a combination of spectroscopic ellipsometry and isothermal adsorption studies) is a valid method to classify and quantify the nanoporosity and correlate it with the WVTR values. Nevertheless, no information is obtained about the macroscale defects or the kinetics of water permeation through the barrier, both essential in assessing the quality of the barrier layer. In this study, electrochemical impedance spectroscopy (EIS) is shown as a sensitive and versatile method to obtain information on nanoporosity and macroscale defects, water permeation, and diffusivity of moisture barrier layers, complementing the barrier property characterization obtained by means of EP and calcium test. EIS is performed on thin SiO2 barrier layers deposited by plasma enhanced-CVD. It allows the determination of the relative water uptake in the SiO2 layers, found to be in agreement with the nanoporosity content inferred by EP. Furthermore, the kinetics of water permeation is followed by EIS, and the diffusivity (D) is determined and found to be in accordance with literature values. Moreover, differently from EP, EIS data are shown to be sensitive to the presence of local macrodefects, correlated with the barrier failure during the calcium test.

Macroscopic quantum tunneling escape of Bose-Einstein condensates

NASA Astrophysics Data System (ADS)

Zhao, Xinxin; Alcala, Diego A.; McLain, Marie A.; Maeda, Kenji; Potnis, Shreyas; Ramos, Ramon; Steinberg, Aephraim M.; Carr, Lincoln D.

2017-12-01

Recent experiments on macroscopic quantum tunneling reveal a nonexponential decay of the number of atoms trapped in a quasibound state behind a potential barrier. Through both experiment and theory, we demonstrate this nonexponential decay results from interactions between atoms. Quantum tunneling of tens of thousands of 87Rb atoms in a Bose-Einstein condensate is modeled by a modified Jeffreys-Wentzel-Kramers-Brillouin model, taking into account the effective time-dependent barrier induced by the mean field. Three-dimensional Gross-Pitaevskii simulations corroborate a mean-field result when compared with experiments. However, with one-dimensional modeling using time-evolving block decimation, we present an effective renormalized mean-field theory that suggests many-body dynamics for which a bare mean-field theory may not apply.

Cross-Cultural Differences in Undergraduate Students' Perceptions of Online Barriers

ERIC Educational Resources Information Center

Olesova, Larisa; Yang, Dazhi; Richardson, Jennifer C.

2011-01-01

The intent of this study was to learn about students' perceived barriers and the impact of those barriers on the quality of online discussions between two distinct cultural groups in Eastern and Northern Siberia (Russia). A mixed-methods approach utilizing surveys and interviews was used to investigate (1) the types of barriers the students…

Simulation study of free-energy barriers in the wetting transition of an oily fluid on a rough surface with reentrant geometry.

PubMed

Savoy, Elizabeth S; Escobedo, Fernando A

2012-11-20

When in contact with a rough solid surface, fluids with low surface tension, such as oils and alkanes, have their lowest free energy in the fully wetted state. For applications where nonwetting by these phillic fluids is desired, some barrier must be introduced to maintain the nonwetted composite state. One way to create this free-energy barrier is to fabricate roughness with reentrant geometry, but the question remains as to whether the free-energy barrier is sufficiently high to prevent wetting. Our goal is to quantify the free-energy landscape for the wetting transition of an oily fluid on a surface of nails and identify significant surface features and conditions that maximize the wetting free-energy barrier (ΔGfwd*). This is a departure from most work on wetting, which focuses on the equilibrium composite and wetted states. We use boxed molecular dynamics (BXD) (Glowacki, D. R.; Paci, E.; Shalashilin, D. V. J. Phys. Chem. B2009, 113, 16603-16611) with a modified control scheme to evaluate both the thermodynamics and kinetics of the transition over a range of surface affinities (chemistry). We find that the reentrant geometry of the nails does create a free-energy barrier to transition for phillic chemistry whereas a corresponding system on straight posts wets spontaneously and, that doubling the nail height more than doubles ΔGfwd*. For neutral to phillic chemistry, the dewetting free-energy barrier is at least an order of magnitude higher than that for wetting, indicating an essentially irreversible wetting transition. Transition rates from BXD simulations and the associated trends agree well with those in our previous study that used forward flux sampling to compute transition rates for similar systems.

Sodium ion transport mechanisms in antiperovskite electrolytes Na 3OBr and Na 4OI 2: An in Situ neutron diffraction study

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

Zhu, Jinlong; Wang, Yonggang; Li, Shuai

Na-rich antiperovskites are recently developed solid electrolytes with enhanced sodium ionic conductivity and show promising functionality as a novel solid electrolyte in an all solid-stat battery. In this work, the sodium ionic transport pathways of the parent compound Na 3OBr, as well as the modified layered antiperovskite Na 4OI 2, were studied and compared through temperature dependent neutron diffraction combined with the maximum entropy method. In the cubic Na 3OBr antiperovskite, the nuclear density distribution maps at 500 K indicate that sodium ions ho within and among oxygen octahedra, and Br - ions are not involved in the tetragonal Namore » 4OI 2 antiperovskite, Na ions, which connect octahedra in the ab plane, have the lowest activation energy barrier. In conclusion, the transport of sodium ions along the c axis is assisted by I - ions.« less