Vorinostat and Combination Chemotherapy With Rituximab in Treating Patients With HIV-Related Diffuse Large B-Cell Non-Hodgkin Lymphoma or Other Aggressive B-Cell Lymphomas

ClinicalTrials.gov

2018-06-07

AIDS-Related Plasmablastic Lymphoma; AIDS-Related Primary Effusion Lymphoma; CD20 Positive; HIV Infection; Plasmablastic Lymphoma; Primary Effusion Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Stage I Diffuse Large B-Cell Lymphoma; Stage I Grade 3 Follicular Lymphoma; Stage II Diffuse Large B-Cell Lymphoma; Stage II Grade 3 Contiguous Follicular Lymphoma; Stage II Grade 3 Non-Contiguous Follicular Lymphoma; Stage III Diffuse Large B-Cell Lymphoma; Stage III Grade 3 Follicular Lymphoma; Stage IV Diffuse Large B-Cell Lymphoma; Stage IV Grade 3 Follicular Lymphoma

Primal-mixed formulations for reaction-diffusion systems on deforming domains

NASA Astrophysics Data System (ADS)

Ruiz-Baier, Ricardo

2015-10-01

We propose a finite element formulation for a coupled elasticity-reaction-diffusion system written in a fully Lagrangian form and governing the spatio-temporal interaction of species inside an elastic, or hyper-elastic body. A primal weak formulation is the baseline model for the reaction-diffusion system written in the deformed domain, and a finite element method with piecewise linear approximations is employed for its spatial discretization. On the other hand, the strain is introduced as mixed variable in the equations of elastodynamics, which in turn acts as coupling field needed to update the diffusion tensor of the modified reaction-diffusion system written in a deformed domain. The discrete mechanical problem yields a mixed finite element scheme based on row-wise Raviart-Thomas elements for stresses, Brezzi-Douglas-Marini elements for displacements, and piecewise constant pressure approximations. The application of the present framework in the study of several coupled biological systems on deforming geometries in two and three spatial dimensions is discussed, and some illustrative examples are provided and extensively analyzed.

Aids to navigation service force mix 2000 project. Volume 2 : development and application of an aids to navigation service force mix decision support system : aid assignments and vessel summary reports

DOT National Transportation Integrated Search

1992-06-01

The Aids to Navigation (ATON) Service Force Mix (SFM) 2000 Project is documented in a Project Overview and three separately bound volumes. This is Volume II. The Project Overview describes the purpose, approach, analysis, and results of the ATON SFM ...

Aids to navigation service force mix 2000 project. Volume 1 : development and application of an aids to navigation service force mix decision support system

DOT National Transportation Integrated Search

1992-07-01

The Aids to Navigation (ATON) Service Force Mix (SFM) 2000 Project is documented in a Project Overview and three separately bound volumes. This is the Project Overview. The Project Overview describes the purpose, approach, analysis, and results of th...

Diffusely reflecting paints including polytetrafluoroethylene and method of manufacture

NASA Technical Reports Server (NTRS)

Schutt, J. B.; Shai, M. C. (Inventor)

1985-01-01

The invention pertains to a high diffuse, reflective paint comprising an alcohol soluble binder, polytetrafluoroethylene (TFE) and an alcohol for coating a substrate and forming an optical reference with a superior Lambertian characteristic. A method for making the paint by first mixing the biner and alcohol, and thereafter by mixing in outgassed TFE is described. A wetting agent may be employed to aid the mixing process.

Mix-and-diffuse serial synchrotron crystallography

DOE PAGES

Beyerlein, Kenneth R.; Dierksmeyer, Dennis; Mariani, Valerio; ...

2017-10-09

Unravelling the interaction of biological macromolecules with ligands and substrates at high spatial and temporal resolution remains a major challenge in structural biology. The development of serial crystallography methods at X-ray free-electron lasers and subsequently at synchrotron light sources allows new approaches to tackle this challenge. Here, a new polyimide tape drive designed for mix-and-diffuse serial crystallography experiments is reported. The structure of lysozyme bound by the competitive inhibitor chitotriose was determined using this device in combination with microfluidic mixers. The electron densities obtained from mixing times of 2 and 50 s show clear binding of chitotriose to the enzymemore » at a high level of detail. Here, the success of this approach shows the potential for high-throughput drug screening and even structural enzymology on short timescales at bright synchrotron light sources.« less

Mix-and-diffuse serial synchrotron crystallography

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

Beyerlein, Kenneth R.; Dierksmeyer, Dennis; Mariani, Valerio

Unravelling the interaction of biological macromolecules with ligands and substrates at high spatial and temporal resolution remains a major challenge in structural biology. The development of serial crystallography methods at X-ray free-electron lasers and subsequently at synchrotron light sources allows new approaches to tackle this challenge. Here, a new polyimide tape drive designed for mix-and-diffuse serial crystallography experiments is reported. The structure of lysozyme bound by the competitive inhibitor chitotriose was determined using this device in combination with microfluidic mixers. The electron densities obtained from mixing times of 2 and 50 s show clear binding of chitotriose to the enzymemore » at a high level of detail. Here, the success of this approach shows the potential for high-throughput drug screening and even structural enzymology on short timescales at bright synchrotron light sources.« less

Epigenetic regulation of HIV, AIDS, and AIDS-related malignancies.

PubMed

Verma, Mukesh

2015-01-01

Although epigenetics is not a new field, its implications for acquired immunodeficiency syndrome (AIDS) research have not been explored fully. To develop therapeutic and preventive approaches against the human immunodeficiency virus (HIV) and AIDS, it is essential to understand the mechanisms of interaction between the virus and the host, involvement of genetic and epigenetic mechanisms, characterization of viral reservoirs, and factors influencing the latency of the virus. Both methylation of viral genes and histone modifications contribute to initiating and maintaining latency and, depending on the context, triggering viral gene repression or expression. This chapter discusses progress made at the National Institutes of Health (NIH), recommendations from the International AIDS Society Scientific Working Group on HIV Cure, and underlying epigenetic regulation. A number of epigenetic inhibitors have shown potential in treating AIDS-related malignancies. Epigenetic drugs approved by the US Food and Drug Administration and their implications for the eradication of HIV/AIDS and AIDS-related malignancies also are discussed.Past and current progress in developing treatments and understanding the molecular mechanisms of AIDS and HIV infection has greatly improved patient survival. However, increased survival has been coupled with the development of cancer at higher rates than those observed among the HIV/AIDS-negative population. During the early days of the AIDS epidemic, the most frequent AIDS-defining malignancies were Kaposi's sarcoma and non-Hodgkin lymphoma (NHL). Now, with increased survival as the result of widespread use in the developed world of highly active antiretroviral therapy (HAART), non-AIDS defining cancers (i.e., anal, skin, and lung cancers, and Hodgkin disease) are on the increase in HIV-infected populations. The current status of AIDS-related malignancies also is discussed.

Stages of AIDS-Related Lymphoma

MedlinePlus

... trials is also available. AIDS-Related Primary Central Nervous System Lymphoma Treatment of AIDS-related primary central nervous system lymphoma may include the following: External radiation therapy . ...

Mixing of secondary organic aerosols versus relative humidity

PubMed Central

Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin

2016-01-01

Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions. PMID:27791066

Mixing of secondary organic aerosols versus relative humidity.

PubMed

Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin; Sullivan, Ryan C; Donahue, Neil M

2016-10-24

Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions.

Stellar evolution with turbulent diffusion. I. A new formalism of mixing.

NASA Astrophysics Data System (ADS)

Deng, L.; Bressan, A.; Chiosi, C.

1996-09-01

In this paper we present a new formulation of diffusive mixing in stellar interiors aimed at casting light on the kind of mixing that should take place in the so-called overshoot regions surrounding fully convective zones. Key points of the analysis are the inclusion the concept of scale length most effective for mixing, by means of which the diffusion coefficient is formulated, and the inclusion of intermittence and stirring, two properties of turbulence known from laboratory fluid dynamics. The formalism is applied to follow the evolution of a 20Msun_ star with composition Z=0.008 and Y=0.25. Depending on the value of the diffusion coefficient holding in the overshoot region, the evolutionary behaviour of the test stars goes from the case of virtually no mixing (semiconvective like structures) to that of full mixing over there (standard overshoot models). Indeed, the efficiency of mixing in this region drives the extension of the intermediate fully convective shell developing at the onset of the the shell H-burning, and in turn the path in the HR Diagram (HRD). Models with low efficiency of mixing burn helium in the core at high effective temperatures, models with intermediate efficiency perform extended loops in the HRD, finally models with high efficiency spend the whole core He-burning phase at low effective temperatures. In order to cast light on this important point of stellar structure, we test whether or not in the regions of the H-burning shell a convective layer can develop. More precisely, we examine whether the Schwarzschild or the Ledoux criterion ought to be adopted in this region. Furthermore, we test the response of stellar models to the kind of mixing supposed to occur in the H-burning shell regions. Finally, comparing the time scale of thermal dissipation to the evolutionary time scale, we get the conclusion that no mixing in this region should occur. The models with intermediate efficiency of mixing and no mixing at all in the shell H

Thermodynamic calculations of oxygen self-diffusion in mixed-oxide nuclear fuels

DOE PAGES

Parfitt, David C.; Cooper, Michael William; Rushton, Michael J.D.; ...

2016-07-29

Mixed-oxide fuels containing uranium with thorium and/or plutonium may play an important part in future nuclear fuel cycles. There are, however, significantly less data available for these materials than conventional uranium dioxide fuel. In the present study, we employ molecular dynamics calculations to simulate the elastic properties and thermal expansivity of a range of mixed oxide compositions. These are then used to support equations of state and oxygen self-diffusion models to provide a self-consistent prediction of the behaviour of these mixed oxide fuels at arbitrary compositions.

Traditional beliefs about the cause of AIDS and AIDS-related stigma in South Africa.

PubMed

Kalichman, S C; Simbayi, L

2004-07-01

AIDS-related stigmas are pervasive in some segments of South African society and stigmas can impede efforts to promote voluntary counselling and testing and other HIV-AIDS prevention efforts. The current study examined associations among the belief that AIDS is caused by spirits and supernatural forces, AIDS-related knowledge and AIDS-related stigmas. A street intercept survey with 487 men and women living in a Black township in Cape Town, South Africa showed that 11% (n=54) believed that AIDS is caused by spirits and supernatural forces, 21% (n=105) were unsure if AIDS is caused by spirits and the supernatural, and 68% (n=355) did not believe that AIDS is caused by spirits and supernatural forces. Multiple logistic regression analyses controlling for participant age, gender, years of education and survey venue showed that people who believed HIV-AIDS is caused by spirits and the supernatural demonstrated significantly more misinformation about AIDS and were significantly more likely to endorse repulsion and social sanction stigmatizing beliefs against people living with HIV-AIDS. However, nearly all associations between beliefs that AIDS is caused by spirits and AIDS stigmas were non-significant when logistic regressions were repeated with AIDS-related knowledge included as a control variable. This finding suggests that relationships between traditional beliefs about the cause of HIV-AIDS and AIDS stigmas are mediated by AIDS-related knowledge. AIDS education efforts are urgently needed to reach people who hold traditional beliefs about AIDS to remedy AIDS stigmas.

Treatment Options for AIDS-Related Lymphoma

MedlinePlus

... trials is also available. AIDS-Related Primary Central Nervous System Lymphoma Treatment of AIDS-related primary central nervous system lymphoma may include the following: External radiation therapy . ...

Computer-Aided Characterization and Diagnosis of Diffuse Liver Diseases Based on Ultrasound Imaging: A Review.

PubMed

Bharti, Puja; Mittal, Deepti; Ananthasivan, Rupa

2016-04-19

Diffuse liver diseases, such as hepatitis, fatty liver, and cirrhosis, are becoming a leading cause of fatality and disability all over the world. Early detection and diagnosis of these diseases is extremely important to save lives and improve effectiveness of treatment. Ultrasound imaging, a noninvasive diagnostic technique, is the most commonly used modality for examining liver abnormalities. However, the accuracy of ultrasound-based diagnosis depends highly on expertise of radiologists. Computer-aided diagnosis systems based on ultrasound imaging assist in fast diagnosis, provide a reliable "second opinion" for experts, and act as an effective tool to measure response of treatment on patients undergoing clinical trials. In this review, we first describe appearance of liver abnormalities in ultrasound images and state the practical issues encountered in characterization of diffuse liver diseases that can be addressed by software algorithms. We then discuss computer-aided diagnosis in general with features and classifiers relevant to diffuse liver diseases. In later sections of this paper, we review the published studies and describe the key findings of those studies. A concise tabular summary comparing image database, features extraction, feature selection, and classification algorithms presented in the published studies is also exhibited. Finally, we conclude with a summary of key findings and directions for further improvements in the areas of accuracy and objectiveness of computer-aided diagnosis. © The Author(s) 2016.

Genetically Modified Peripheral Blood Stem Cell Transplant in Treating Patients With HIV-Associated Non-Hodgkin or Hodgkin Lymphoma

ClinicalTrials.gov

2015-05-06

Adult Nasal Type Extranodal NK/T-cell Lymphoma; AIDS-related Diffuse Large Cell Lymphoma; AIDS-related Diffuse Mixed Cell Lymphoma; AIDS-related Diffuse Small Cleaved Cell Lymphoma; AIDS-related Immunoblastic Large Cell Lymphoma; AIDS-related Lymphoblastic Lymphoma; AIDS-related Peripheral/Systemic Lymphoma; AIDS-related Small Noncleaved Cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Hepatosplenic T-cell Lymphoma; HIV-associated Hodgkin Lymphoma; Intraocular Lymphoma; Nodal Marginal Zone B-cell Lymphoma; Noncutaneous Extranodal Lymphoma; Peripheral T-cell Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Adult T-cell Leukemia/Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent Small Lymphocytic Lymphoma; Refractory Hairy Cell Leukemia; Small Intestine Lymphoma; Splenic Marginal Zone Lymphoma; Stage I AIDS-related Lymphoma; Stage II AIDS-related Lymphoma; Stage III AIDS-related Lymphoma; Stage IV AIDS-related Lymphoma; T-cell Large Granular Lymphocyte Leukemia; Testicular Lymphoma; Waldenström Macroglobulinemia

General Information about AIDS-Related Lymphoma

MedlinePlus

... AIDS-Related Lymphoma Treatment (PDQ®)–Patient Version General Information About AIDS-Related Lymphoma Go to Health Professional ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

Diffusion and Mixing in Globular Clusters

NASA Astrophysics Data System (ADS)

Meiron, Yohai; Kocsis, Bence

2018-03-01

Collisional relaxation describes the stochastic process with which a self-gravitating system near equilibrium evolves in phase-space due to the fluctuating gravitational field of the system. The characteristic timescale of this process is called the relaxation time. In this paper, we highlight the difference between two measures of the relaxation time in globular clusters: (1) the diffusion time with which the isolating integrals of motion (i.e., energy E and angular momentum magnitude L) of individual stars change stochastically and (2) the asymptotic timescale required for a family of orbits to mix in the cluster. More specifically, the former corresponds to the instantaneous rate of change of a star’s E or L, while the latter corresponds to the timescale for the stars to statistically forget their initial conditions. We show that the diffusion timescales of E and L vary systematically around the commonly used half-mass relaxation time in different regions of the cluster by a factor of ∼10 and ∼100, respectively, for more than 20% of the stars. We define the mixedness of an orbital family at any given time as the correlation coefficient between its E or L probability distribution functions and those of the whole cluster. Using Monte Carlo simulations, we find that mixedness converges asymptotically exponentially with a decay timescale that is ∼10 times the half-mass relaxation time.

Stimulated echo diffusion tensor imaging (STEAM-DTI) with varying diffusion times as a probe of breast tissue.

PubMed

Teruel, Jose R; Cho, Gene Y; Moccaldi Rt, Melanie; Goa, Pål E; Bathen, Tone F; Feiweier, Thorsten; Kim, Sungheon G; Moy, Linda; Sigmund, Eric E

2017-01-01

To explore the application of diffusion tensor imaging (DTI) for breast tissue and breast pathologies using a stimulated-echo acquisition mode (STEAM) with variable diffusion times. In this Health Insurance Portability and Accountability Act-compliant study, approved by the local institutional review board, eight patients and six healthy volunteers underwent an MRI examination at 3 Tesla including STEAM-DTI with several diffusion times ranging from 68.5 to 902.5 ms. A DTI model was fitted to the data for each diffusion time, and parametric maps of mean diffusivity, fractional anisotropy, axial diffusivity, and radial diffusivity were computed for healthy fibroglandular tissue (FGT) and lesions. The median value of radial diffusivity for FGT was fitted to a linear decay to obtain an estimation of the surface-to-volume ratio, from which the radial diameter was calculated. For healthy FGT, radial diffusivity presented a linear decay with the square root of the diffusion time resulting in a range of estimated radial diameters from 202 to 496 µm, while axial diffusivity presented a nearly time-independent diffusion. Residual fat signal was reduced at longer diffusion times due to the shorter T1 of fat. Residual fat signal to the overall signal in the healthy volunteers' FGT was found to range from 2.39% to 2.55% (shortest mixing time), and from 0.40% to 0.51% (longest mixing time) for the b500 images. The use of variable diffusion times may provide an in vivo noninvasive tool to probe diffusion lengths in breast tissue and breast pathology, and might aid by improving fat suppression at longer diffusion times. 2 J. Magn. Reson. Imaging 2017;45:84-93. © 2016 International Society for Magnetic Resonance in Medicine.

Physicians Mutual Aid Group: A Response to AIDS-Related Burnout.

ERIC Educational Resources Information Center

Garside, Bruce

1993-01-01

Describes origins and functioning of physician's mutual aid group for physicians providing primary care to people with Acquired Immune Deficiency Syndrome (AIDS). Offers suggestions related to overcoming resistance physicians might have to participating in such a group and reviews modalities that were helpful in facilitating participants' ability…

Mixing Efficiency in the Ocean.

PubMed

Gregg, M C; D'Asaro, E A; Riley, J J; Kunze, E

2018-01-03

Mixing efficiency is the ratio of the net change in potential energy to the energy expended in producing the mixing. Parameterizations of efficiency and of related mixing coefficients are needed to estimate diapycnal diffusivity from measurements of the turbulent dissipation rate. Comparing diffusivities from microstructure profiling with those inferred from the thickening rate of four simultaneous tracer releases has verified, within observational accuracy, 0.2 as the mixing coefficient over a 30-fold range of diapycnal diffusivities. Although some mixing coefficients can be estimated from pycnocline measurements, at present mixing efficiency must be obtained from channel flows, laboratory experiments, and numerical simulations. Reviewing the different approaches demonstrates that estimates and parameterizations for mixing efficiency and coefficients are not converging beyond the at-sea comparisons with tracer releases, leading to recommendations for a community approach to address this important issue.

Mixing Efficiency in the Ocean

NASA Astrophysics Data System (ADS)

Gregg, M. C.; D'Asaro, E. A.; Riley, J. J.; Kunze, E.

2018-01-01

Mixing efficiency is the ratio of the net change in potential energy to the energy expended in producing the mixing. Parameterizations of efficiency and of related mixing coefficients are needed to estimate diapycnal diffusivity from measurements of the turbulent dissipation rate. Comparing diffusivities from microstructure profiling with those inferred from the thickening rate of four simultaneous tracer releases has verified, within observational accuracy, 0.2 as the mixing coefficient over a 30-fold range of diapycnal diffusivities. Although some mixing coefficients can be estimated from pycnocline measurements, at present mixing efficiency must be obtained from channel flows, laboratory experiments, and numerical simulations. Reviewing the different approaches demonstrates that estimates and parameterizations for mixing efficiency and coefficients are not converging beyond the at-sea comparisons with tracer releases, leading to recommendations for a community approach to address this important issue.

Unity and diversity in mixing: Stretching, diffusion, breakup, and aggregation in chaotic flows

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

Ottino, J.M.

1991-05-01

Experiments and theory have produced a reasonably good qualitative understanding of the evolution of chaotic mixing of passive tracers, especially in two-dimensional time-periodic flow fields. Such an understanding forms a fabric for the evolution of breakup, aggregation, and diffusion-controlled reactions in more complex flows. These systems can be viewed as a population of microstructures'' whose behavior is dictated by iterations of a chaotic flow; microstructures break, diffuse, and aggregate, causing the population to evolve in space and time. This paper presents simple physical models for such processes. Self-similarity is common to all the problems; examples arise in the context ofmore » the distribution of stretchings within chaotic flows, in the asymptotic evolution of diffusion-reaction processes at striation thickness scales, in the equilibrium distribution of drop sizes generated upon mixing of immiscible fluids, in the equations describing mean-field kinetics of coagulation, in the sequence of actions necessary for the destruction of islands in two-dimensional flow, and in the fractal structure of clusters produced upon aggregation in chaotic flows.« less

Women and AIDS-Related Concerns

PubMed Central

Cochran, Susan D.; Mays, Vickie M.

2014-01-01

Acquired Immunodeficiency Syndrome (AIDS) has important implications for the practice of psychology. As the epidemic continues, the role of behavior change and psychosocial factors in the spread and transmission of Human Immunodeficiency Virus (HIV) infections assumes increasing significance. Psychologists, as behavior change experts, have a special and challenging role to play in educating the public, particularly women, about AIDS. This article examines AIDS- and HIV-related concerns in women with a focus on the personal dilemmas for the practicing psychologist, problems in health behavior advocacy, and methods and pitfalls in modifying sexual behaviors. PMID:2930055

Microstructure Imaging of Crossing (MIX) White Matter Fibers from diffusion MRI

PubMed Central

Farooq, Hamza; Xu, Junqian; Nam, Jung Who; Keefe, Daniel F.; Yacoub, Essa; Georgiou, Tryphon; Lenglet, Christophe

2016-01-01

Diffusion MRI (dMRI) reveals microstructural features of the brain white matter by quantifying the anisotropic diffusion of water molecules within axonal bundles. Yet, identifying features such as axonal orientation dispersion, density, diameter, etc., in complex white matter fiber configurations (e.g. crossings) has proved challenging. Besides optimized data acquisition and advanced biophysical models, computational procedures to fit such models to the data are critical. However, these procedures have been largely overlooked by the dMRI microstructure community and new, more versatile, approaches are needed to solve complex biophysical model fitting problems. Existing methods are limited to models assuming single fiber orientation, relevant to limited brain areas like the corpus callosum, or multiple orientations but without the ability to extract detailed microstructural features. Here, we introduce a new and versatile optimization technique (MIX), which enables microstructure imaging of crossing white matter fibers. We provide a MATLAB implementation of MIX, and demonstrate its applicability to general microstructure models in fiber crossings using synthetic as well as ex-vivo and in-vivo brain data. PMID:27982056

Photoionized Mixing Layer Models of the Diffuse Ionized Gas

NASA Astrophysics Data System (ADS)

Binette, Luc; Flores-Fajardo, Nahiely; Raga, Alejandro C.; Drissen, Laurent; Morisset, Christophe

2009-04-01

It is generally believed that O stars, confined near the galactic midplane, are somehow able to photoionize a significant fraction of what is termed the "diffuse ionized gas" (DIG) of spiral galaxies, which can extend up to 1-2 kpc above the galactic midplane. The heating of the DIG remains poorly understood, however, as simple photoionization models do not reproduce the observed line ratio correlations well or the DIG temperature. We present turbulent mixing layer (TML) models in which warm photoionized condensations are immersed in a hot supersonic wind. Turbulent dissipation and mixing generate an intermediate region where the gas is accelerated, heated, and mixed. The emission spectrum of such layers is compared with observations of Rand of the DIG in the edge-on spiral NGC 891. We generate two sequence of models that fit the line ratio correlations between [S II]/Hα, [O I]/Hα, [N II]/[S II], and [O III]/Hβ reasonably well. In one sequence of models, the hot wind velocity increases, while in the other, the ionization parameter and layer opacity increase. Despite the success of the mixing layer models, the overall efficiency in reprocessing the stellar UV is much too low, much less than 1%, which compels us to reject the TML model in its present form.

Local Interactions of Hydrometeors by Diffusion in Mixed-Phase Clouds

NASA Astrophysics Data System (ADS)

Baumgartner, Manuel; Spichtinger, Peter

2017-04-01

Mixed-phase clouds, containing both ice particles and liquid droplets, are important for the Earth-Atmosphere system. They modulate the radiation budget by a combination of albedo effect and greenhouse effect. In contrast to liquid water clouds, the radiative impact of clouds containing ice particles is still uncertain. Scattering and absorption highly depends in microphysical properties of ice crystals, e.g. size and shape. In addition, most precipitation on Earth forms via the ice phase. Thus, better understanding of ice processes as well as their representation in models is required. A key process for determining shape and size of ice crystals is diffusional growth. Diffusion processes in mixed-phase clouds are highly uncertain; in addition they are usually highly simplified in cloud models, especially in bulk microphysics parameterizations. The direct interaction between cloud droplets and ice particles, due to spatial inhomogeneities, is ignored; the particles can only interact via their environmental conditions. Local effects as supply of supersaturation due to clusters of droplets around ice particles are usually not represented, although they form the physical basis of the Wegener-Bergeron-Findeisen process. We present direct numerical simulations of the interaction of single ice particles and droplets, especially their local competition for the available water vapor. In addition, we show an approach to parameterize local interactions by diffusion. The suggested parameterization uses local steady-state solutions of the diffusion equations for water vapor for an ice particle as well as a droplet. The individual solutions are coupled together to obtain the desired interaction. We show some results of the scheme as implemented in a parcel model.

AIDS-related discrimination in Asia.

PubMed

Paxton, S; Gonzales, G; Uppakaew, K; Abraham, K K; Okta, S; Green, C; Nair, K S; Merati, T Parwati; Thephthien, B; Marin, M; Quesada, A

2005-05-01

The Asia Pacific Network of People Living with HIV/AIDS (APN+) conducted the first regional documentation of AIDS-related discrimination in Asia. This project was an action-based, peer-implemented study that aimed to develop an understanding of the nature, pattern and extent of AIDS-related discrimination in several Asian countries. Trained HIV-positive people interviewed 764 positive people in four countries (India 302; Indonesia 42; Thailand 338; the Philippines 82) using a structured questionnaire. Findings indicate that the major area of discrimination in each country is within the health sector, where over half of those surveyed experienced some form of discrimination. In all countries, the majority of people did not receive pre-test counselling before being tested for HIV. People who reported coerced testing were significantly more likely than other respondents to face subsequent AIDS-related discrimination. A considerable number of respondents were refused treatment after being diagnosed with HIV and many experienced delayed provision of treatment or health services. Breaches of confidentiality by health workers were common. Within the family and the community, women were significantly more likely to experience discrimination than men, including ridicule and harassment, physical assault and being forced to change their place of residence because of their HIV status. These findings have serious implications, particularly in light of the increasing trend in many countries to test all pregnant women in order to prevent transmission of HIV to their unborn children.

[Aged woman's vulnerability related to AIDS].

PubMed

Silva, Carla Marins; Lopes, Fernanda Maria do Valle Martins; Vargens, Octavio Muniz da Costa

2010-09-01

This article is a systhematic literature review including the period from 1994 to 2009, whose objective was to discuss the aged woman's vulnerability in relation to Acquired Imunodeficiency Syndrome (Aids). The search for scientific texts was accomplished in the following databases: Biblioteca Virtual em Saúde, Scientific Eletronic Library Online (SciELO), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) and Medical Literature Analysis and Retrieval System Online (MEDLINE). The descriptors used were vulnerability, woman and Aids. Eighteen texts were analyzed, including articles in scientific journals, thesis and dissertations. As a conclusion, it was noted that aged women and vulnerability to Aids are directly related, through gender characteristics including submission and that were built historical and socially. We consider as fundamental the development of studies which may generate publications accessible to women, in order to help them see themselves as persons vulnerable to Aids contagion just for being women.

Combined Microfluidic-Eectric Diffused Mixing of Living Cells in Continuous Flow

NASA Astrophysics Data System (ADS)

Ming-Wen Wang,

2010-02-01

The mixing process is a crucially important stage in the operation of biological and chemical microfluidic devices. If the mixing is inadequate, reactants do not fully interact with each other, and the device may not operate properly. This paper describes a simplified microfluidic mixer (different from a chaotic mixer) which can uniformly mix a buffer solution with living cells by applying an AC electric charge. Diffusion of the living cells into the buffer solution occurs rapidly following the interface of the flow stream with the electric charge; no further agitating step is needed. To accomplish this, an asymmetric pair of electrodes was integrated at the inlets of the buffer solution and the cells fluid. When the buffer solution and the cells fluid were introduced into one flow path, they remained limited to that flow stream. When the electrodes were charged, however, the cells in a short distance were efficiently moved into the solution flow, and the original fluids were mixed. The mixing efficiency depends on the polarizability of the cells, and this in turn is governed by the dielectric properties of the cells, the medium, and the solvent. This micro device, capable of efficiently mixing living cells with a buffer solution, may potentially allow biological mixing to be done outside of hospitals, in facilities without biological analyzing instruments.

Mixed conduction and chemical diffusion in a Pb(Zr0.53,Ti0.47)O3 buried capacitor structure

NASA Astrophysics Data System (ADS)

Donnelly, Niall J.; Randall, Clive A.

2010-02-01

Impedance spectroscopy is performed on a buried capacitor structure composed of a PZT-0.75% Nb ceramic with platinum electrodes. The ionic and electronic conductivities (σion,σelec) are extracted from the impedance spectra using an equivalent circuit based on the premise of mixed conduction. In the temperature range 500-700 °C, a change in local pO2 mainly affects σelec, suggesting that the samples are ionically compensated, i.e., [VO••]=[VPb″]. The chemical diffusion coefficient, D˜, is obtained by a conductivity relaxation technique assuming two-dimensional diffusion geometry. In comparison to BaTiO3, or SrTiO3, the chemical diffusivity is found to be relatively high, D˜=2.0×10-4 cm2 s-1 (700 °C, in air).

Investigating the Metallicity–Mixing-length Relation

NASA Astrophysics Data System (ADS)

Viani, Lucas S.; Basu, Sarbani; Joel Ong J., M.; Bonaca, Ana; Chaplin, William J.

2018-05-01

Stellar models typically use the mixing-length approximation as a way to implement convection in a simplified manner. While conventionally the value of the mixing-length parameter, α, used is the solar-calibrated value, many studies have shown that other values of α are needed to properly model stars. This uncertainty in the value of the mixing-length parameter is a major source of error in stellar models and isochrones. Using asteroseismic data, we determine the value of the mixing-length parameter required to properly model a set of about 450 stars ranging in log g, {T}eff}, and [{Fe}/{{H}}]. The relationship between the value of α required and the properties of the star is then investigated. For Eddington atmosphere, non-diffusion models, we find that the value of α can be approximated by a linear model, in the form of α /{α }ȯ =5.426{--}0.101 {log}(g)-1.071 {log}({T}eff}) +0.437([{Fe}/{{H}}]). This process is repeated using a variety of model physics, as well as compared with previous studies and results from 3D convective simulations.

Gravity Wave Mixing and Effective Diffusivity for Minor Chemical Constituents in the Mesosphere/Lower Thermosphere

NASA Astrophysics Data System (ADS)

Grygalashvyly, M.; Becker, E.; Sonnemann, G. R.

2012-06-01

The influence of gravity waves (GWs) on the distributions of minor chemical constituents in the mesosphere-lower thermosphere (MLT) is studied on the basis of the effective diffusivity concept. The mixing ratios of chemical species used for calculations of the effective diffusivity are obtained from numerical experiments with an off-line coupled model of the dynamics and chemistry abbreviated as KMCM-MECTM (Kuehlungsborn Mechanistic general Circulation Model—MEsospheric Chemistry-Transport Model). In our control simulation the MECTM is driven with the full dynamical fields from an annual cycle simulation with the KMCM, where mid-frequency GWs down to horizontal wavelengths of 350 km are resolved and their wave-mean flow interaction is self-consistently induced by an advanced turbulence model. A perturbation simulation with the MECTM is defined by eliminating all meso-scale variations with horizontal wavelengths shorter than 1000 km from the dynamical fields by means of spectral filtering before running the MECTM. The response of the MECTM to GWs perturbations reveals strong effects on the minor chemical constituents. We show by theoretical arguments and numerical diagnostics that GWs have direct, down-gradient mixing effects on all long-lived minor chemical species that possess a mean vertical gradient in the MLT. Introducing the term wave diffusion (WD) and showing that wave mixing yields approximately the same WD coefficient for different chemical constituents, we argue that it is a useful tool for diagnostic irreversible transport processes. We also present a detailed discussion of the gravity-wave mixing effects on the photochemistry and highlight the consequences for the general circulation of the MLT.

Diffusive exchange of trace elements between alkaline melts: Implications for element fractionation and timescale estimations during magma mixing

NASA Astrophysics Data System (ADS)

González-Garcia, Diego; Petrelli, Maurizio; Behrens, Harald; Vetere, Francesco; Fischer, Lennart A.; Morgavi, Daniele; Perugini, Diego

2018-07-01

. These results indicate that diffusive fractionation of trace elements is possible during magma mixing events, especially in the more silicic melts, and that the presence of water in such events can lead to enhanced chemical diffusive mixing efficiency, affecting also the estimation of mixing to eruption timescales.

Endoscopic appearance of AIDS-related gastrointestinal lymphoma with c-MYC rearrangements: case report and literature review.

PubMed

Tanaka, Shohei; Nagata, Naoyoshi; Mine, Sohtaro; Igari, Toru; Kobayashi, Taiichiro; Sugihara, Jun; Honda, Haruhito; Teruya, Katsuji; Kikuchi, Yoshimi; Oka, Shinichi; Uemura, Naomi

2013-08-07

Acquired immune deficiency syndrome (AIDS)-related lymphoma (ARL) remains the main cause of AIDS-related deaths in the highly active anti-retroviral therapy (HAART) era. Recently, rearrangement of MYC is associated with poor prognosis in patients with diffuse large B-cell lymphoma. Here, we report a rare case of gastrointestinal (GI)-ARL with MYC rearrangements and coinfected with Epstein-Barr virus (EBV) infection presenting with various endoscopic findings. A 38-year-old homosexual man who presented with anemia and was diagnosed with an human immunodeficiency virus infection for the first time. GI endoscopy revealed multiple dish-like lesions, ulcerations, bloody spots, nodular masses with active bleeding in the stomach, erythematous flat lesions in the duodenum, and multiple nodular masses in the colon and rectum. Magnified endoscopy with narrow band imaging showed a honeycomb-like pattern without irregular microvessels in the dish-like lesions of the stomach. Biopsy specimens from the stomach, duodenum, colon, and rectum revealed diffuse large B-cell lymphoma concomitant with EBV infection that was detected by high tissue EBV-polymerase chain reaction levels and Epstein-Barr virus small RNAs in situ hybridization. Fluorescence in situ hybridization analysis revealed a fusion between the immunoglobulin heavy chain (IgH) and c-MYC genes, but not between the IgH and BCL2 loci. After 1-mo of treatment with HAART and R-CHOP, endoscopic appearance improved remarkably, and the histological features of the biopsy specimens revealed no evidence of lymphoma. However, he died from multiple organ failure on the 139(th) day after diagnosis. The cause of his poor outcome may be related to MYC rearrangement. The GI tract involvement in ARL is rarely reported, and its endoscopic findings are various and may be different from those in non-AIDS GI lymphoma; thus, we also conducted a literature review of GI-ARL cases.

Endoscopic appearance of AIDS-related gastrointestinal lymphoma with c-MYC rearrangements: Case report and literature review

PubMed Central

Tanaka, Shohei; Nagata, Naoyoshi; Mine, Sohtaro; Igari, Toru; Kobayashi, Taiichiro; Sugihara, Jun; Honda, Haruhito; Teruya, Katsuji; Kikuchi, Yoshimi; Oka, Shinichi; Uemura, Naomi

2013-01-01

Acquired immune deficiency syndrome (AIDS)-related lymphoma (ARL) remains the main cause of AIDS-related deaths in the highly active anti-retroviral therapy (HAART) era. Recently, rearrangement of MYC is associated with poor prognosis in patients with diffuse large B-cell lymphoma. Here, we report a rare case of gastrointestinal (GI)-ARL with MYC rearrangements and coinfected with Epstein-Barr virus (EBV) infection presenting with various endoscopic findings. A 38-year-old homosexual man who presented with anemia and was diagnosed with an human immunodeficiency virus infection for the first time. GI endoscopy revealed multiple dish-like lesions, ulcerations, bloody spots, nodular masses with active bleeding in the stomach, erythematous flat lesions in the duodenum, and multiple nodular masses in the colon and rectum. Magnified endoscopy with narrow band imaging showed a honeycomb-like pattern without irregular microvessels in the dish-like lesions of the stomach. Biopsy specimens from the stomach, duodenum, colon, and rectum revealed diffuse large B-cell lymphoma concomitant with EBV infection that was detected by high tissue EBV-polymerase chain reaction levels and Epstein-Barr virus small RNAs in situ hybridization. Fluorescence in situ hybridization analysis revealed a fusion between the immunoglobulin heavy chain (IgH) and c-MYC genes, but not between the IgH and BCL2 loci. After 1-mo of treatment with HAART and R-CHOP, endoscopic appearance improved remarkably, and the histological features of the biopsy specimens revealed no evidence of lymphoma. However, he died from multiple organ failure on the 139th day after diagnosis. The cause of his poor outcome may be related to MYC rearrangement. The GI tract involvement in ARL is rarely reported, and its endoscopic findings are various and may be different from those in non-AIDS GI lymphoma; thus, we also conducted a literature review of GI-ARL cases. PMID:23922484

Electrokinetic mixing at high zeta potentials: ionic size effects on cross stream diffusion.

PubMed

Ahmadian Yazdi, Alireza; Sadeghi, Arman; Saidi, Mohammad Hassan

2015-03-15

The electrokinetic phenomena at high zeta potentials may show several unique features which are not normally observed. One of these features is the ionic size (steric) effect associated with the solutions of high ionic concentration. In the present work, attention is given to the influences of finite ionic size on the cross stream diffusion process in an electrokinetically actuated Y-shaped micromixer. The method consists of a finite difference based numerical approach for non-uniform grid which is applied to the dimensionless form of the governing equations, including the modified Poisson-Boltzmann equation. The results reveal that, neglecting the ionic size at high zeta potentials gives rise to the overestimation of the mixing length, because the steric effects retard liquid flow, thereby enhancing the mixing efficiency. The importance of steric effects is found to be more intense for channels of smaller width to height ratio. It is also observed that, in sharp contrast to the conditions that the ions are treated as point charges, increasing the zeta potential improves the cross stream diffusion when incorporating the ionic size. Moreover, increasing the EDL thickness decreases the mixing length, whereas the opposite is true for the channel aspect ratio. Copyright © 2014 Elsevier Inc. All rights reserved.

The arbitrary order mixed mimetic finite difference method for the diffusion equation

DOE PAGES

Gyrya, Vitaliy; Lipnikov, Konstantin; Manzini, Gianmarco

2016-05-01

Here, we propose an arbitrary-order accurate mimetic finite difference (MFD) method for the approximation of diffusion problems in mixed form on unstructured polygonal and polyhedral meshes. As usual in the mimetic numerical technology, the method satisfies local consistency and stability conditions, which determines the accuracy and the well-posedness of the resulting approximation. The method also requires the definition of a high-order discrete divergence operator that is the discrete analog of the divergence operator and is acting on the degrees of freedom. The new family of mimetic methods is proved theoretically to be convergent and optimal error estimates for flux andmore » scalar variable are derived from the convergence analysis. A numerical experiment confirms the high-order accuracy of the method in solving diffusion problems with variable diffusion tensor. It is worth mentioning that the approximation of the scalar variable presents a superconvergence effect.« less

Diffusion of major and trace elements in natural silicate melts as a tool to investigate timescales in magma mixing

NASA Astrophysics Data System (ADS)

González-García, Diego; Zezza, Angela; Behrens, Harald; Vetere, Francesco; Petrelli, Maurizio; Morgavi, Daniele; Perugini, Diego

2016-04-01

New melt injection into a shallow magma chamber is regarded as one of the potential triggers for explosive volcanic eruptions. Chemical diffusion occurring between the two mixing melts is a time-dependent process, and thus has the potential to shed light on the timescales involved in magma mixing events leading to an eruption. In order to achieve this, a complete database of diffusion coefficients in natural melts is a necessary prerequisite. We have carried out a set of 12 diffusion couple experiments in order to determine diffusion coefficients (D) of major and trace elements in two natural silicate melts. Two end-members from the Vulcano island (Aeolian archipelago, Italy) have been chosen for the experiments: a shoshonite (Vulcanello lava platform) and a rhyolitic obsidian (Pietre Cotte lava flow, La Fossa cone). Glasses from each end-member with added water contents of 0 wt%, 1 wt% and 2 wt% were produced in an Internally Heated Pressure Vessel (IHPV). Two glass cylinders with similar water content but different base composition are inserted in Au-Pd capsules and experiments are run in the IHPV at 1200° C with pressure from 0.5 to 3 kbar. Experiment capsules are rapidly quenched and analyzed by FTIR, EPMA and LA-ICP-MS for H2O, major and trace elements, respectively, along 2 mm linear profiles extending across the interface. A Boltzmann-Matano approach is used to obtain concentration-dependent diffusivities. The obtained concentration-distance profiles are asymmetric and extend deeper into the shoshonite relative to the rhyolite, indicating that diffusion is slower in the latter. Results show that diffusivities are notably accelerated by the presence of H2O in the melt. Experiments performed by using water-free glass show diffusivities one order of magnitude lower compared to glasses containing up to 2 wt% H2O. The effect of pressure, in the investigated range, is negligible and falls within measurement error. Among major elements, Si and Ti are the slowest

Trends in AIDS incidence and AIDS-related mortality in British Columbia between 1981 and 2013

PubMed Central

Lima, Viviane D.; Lourenço, Lillian; Yip, Benita; Hogg, Robert S.; Phillips, Peter; Montaner, Julio S.G.

2015-01-01

Background Appropriate use of highly active antiretroviral therapy (HAART) can markedly decrease the risk of progression to acquired immunodeficiency syndrome (AIDS) and of premature mortality. We aimed to characterize the trends between 1981 and 2013 in AIDS-defining illnesses (ADIs) and in the number AIDS-related deaths in British Columbia (BC), Canada. Methods We included data of 3550 HIV-positive individuals, aged 19 years or older, from different administrative databases in BC. We estimated the relative risk of developing an ADI over time using a Negative Binomial model, and we investigated trends in the percentage of all deaths associated with AIDS using generalized additive models. Findings The number of ADIs has decreased dramatically to its lowest level in 2013. The peak of the AIDS epidemic in BC happened in 1994 with 696 ADIs being reported (rate 42 ADIs per 100 person-years). Since 1997, the number of ADIs decreased from 253 (rate 7 per 100 person-years) to 84 cases in 2013 (rate 1 per 100 person-years) (p-value equals to zero for the trend in the number of ADIs). We have also shown that out of 22 ADIs considered, only PCP maintained its prominent ranking (albeit with much reduced overall prevalence). Finally, we observed that over time very few deaths were related to AIDS-related causes, especially in the most recent years. Interpretation We showed that the number of new ADIs and AIDS-related mortality have been decreasing rapidly over time in BC. These results provide further evidence that integrated comprehensive free programs that facilitate testing, and deliver treatment and care to this population can be effective in markedly decreasing AIDS-related morbidity and mortality, thus suggesting that controlling and eventually ending AIDS is possible. Funding The British Columbia Ministry of Health, the US National Institutes of Health, the US National Institute on Drug Abuse, the Canadian Institutes of Health Research, and the Michael Institute for

Impulsive synchronization of stochastic reaction-diffusion neural networks with mixed time delays.

PubMed

Sheng, Yin; Zeng, Zhigang

2018-07-01

This paper discusses impulsive synchronization of stochastic reaction-diffusion neural networks with Dirichlet boundary conditions and hybrid time delays. By virtue of inequality techniques, theories of stochastic analysis, linear matrix inequalities, and the contradiction method, sufficient criteria are proposed to ensure exponential synchronization of the addressed stochastic reaction-diffusion neural networks with mixed time delays via a designed impulsive controller. Compared with some recent studies, the neural network models herein are more general, some restrictions are relaxed, and the obtained conditions enhance and generalize some published ones. Finally, two numerical simulations are performed to substantiate the validity and merits of the developed theoretical analysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multivariate-$t$ nonlinear mixed models with application to censored multi-outcome AIDS studies.

PubMed

Lin, Tsung-I; Wang, Wan-Lun

2017-10-01

In multivariate longitudinal HIV/AIDS studies, multi-outcome repeated measures on each patient over time may contain outliers, and the viral loads are often subject to a upper or lower limit of detection depending on the quantification assays. In this article, we consider an extension of the multivariate nonlinear mixed-effects model by adopting a joint multivariate-$t$ distribution for random effects and within-subject errors and taking the censoring information of multiple responses into account. The proposed model is called the multivariate-$t$ nonlinear mixed-effects model with censored responses (MtNLMMC), allowing for analyzing multi-outcome longitudinal data exhibiting nonlinear growth patterns with censorship and fat-tailed behavior. Utilizing the Taylor-series linearization method, a pseudo-data version of expectation conditional maximization either (ECME) algorithm is developed for iteratively carrying out maximum likelihood estimation. We illustrate our techniques with two data examples from HIV/AIDS studies. Experimental results signify that the MtNLMMC performs favorably compared to its Gaussian analogue and some existing approaches. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The complex fluid dynamics of simple diffusion

NASA Astrophysics Data System (ADS)

Vold, Erik

2017-11-01

Diffusion as the mass transport process responsible for mixing fluids at the atomic level is often underestimated in its complexity. An initial discontinuity between two species of different atomic masses exhibits a mass density discontinuity under isothermal pressure equilibrium implying equal species molar densities. The self-consistent kinetic transport processes across such an interface leads to a zero sum of mass flux relative to the center of mass and so diffusion alone cannot relax an initially stationary mass discontinuity nor broaden the density profile at the interface. The diffusive mixing leads to a molar imbalance which drives a center of mass velocity which moves the heavier species toward the lighter species leading to the interfacial density relaxation. Simultaneously, the species non-zero molar flux modifies the pressure profile in a transient wave and in a local perturbation. The resulting center of mass velocity has two components; one, associated with the divergence of the flow, persists in the diffusive mixing region throughout the diffusive mixing process, and two, travelling waves at the front of the pressure perturbations propagate away from the mixing region. The momentum in these waves is necessary to maintain momentum conservation in the center of mass frame. Thus, in a number of ways, the diffusive mixing provides feedback into the small scale advective motions. Numerical methods which diffuse all species assuming P-T equilibrium may not recover the subtle dynamics of mass transport at an interface. Work performed by the LANS, LLC, under USDOE Contract No. DE-AC52-06NA25396, funded by the (ASC) Program.

Skew-t partially linear mixed-effects models for AIDS clinical studies.

PubMed

Lu, Tao

2016-01-01

We propose partially linear mixed-effects models with asymmetry and missingness to investigate the relationship between two biomarkers in clinical studies. The proposed models take into account irregular time effects commonly observed in clinical studies under a semiparametric model framework. In addition, commonly assumed symmetric distributions for model errors are substituted by asymmetric distribution to account for skewness. Further, informative missing data mechanism is accounted for. A Bayesian approach is developed to perform parameter estimation simultaneously. The proposed model and method are applied to an AIDS dataset and comparisons with alternative models are performed.

Epidemiological situation of acquired immunodeficiency syndrome (AIDS)-related mortality in a municipality in northeastern Brazil. A retrospective cross-sectional study.

PubMed

Silva, Luana Rodrigues da; Araújo, Ellen Thallita Hill; Carvalho, Moisés Lopes; Almeida, Camila Aparecida Pinheiro Landim; Oliveira, Adélia Dalva da Silva; Carvalho, Patrícia Maria Gomes de; Rodrigues, Tatyanne Silva; Campelo, Viriato

2018-01-01

The number of acquired immunodeficiency syndrome (AIDS)-related deaths covers different segments of the population differently, making monitoring of this mortality essential. The aim of this study was to describe the epidemiological situation of AIDS-related mortality in a municipality in the northeastern region of Brazil. Retrospective cross-sectional study based on data from death certificates in the mortality information system of the Health Information Center, Municipal Health Foundation, Brazil. Between 2003 and 2013, we investigated death certificates on which AIDS-related mortality was reported. Sociodemographic data, year, place, type of establishment where death occurred and underlying and associated causes that led to AIDS-related death were described. The Mann-Kendall test was used to verify the growth trend of the standardized mortality rate over the period studied. Among the 1,066 AIDS-related deaths, 69.7% were among men; 47.2% of the individuals were 28-41 years of age, 32.7% had had 4-7 years of schooling, 66.9% were pardos (mixed race), 55.7% were unmarried and 15.3% were housekeepers. Hospitals were the site of 97% of the deaths, and 91% occurred at public hospitals. Respiratory failure was the main cause of death. The prevalence of infectious and parasitic diseases was 99.0%. AIDS-related mortality increased by 160% over the period studied, from 5.5/100,000 inhabitants in 2003 to 14.3/100,000 in 2013. In the Brazilian municipality studied here, AIDS-related mortality was most prevalent among men and young adults of lower socioeconomic level. Over the period studied, the mortality rate increased.

RO4929097 and Capecitabine in Treating Patients With Refractory Solid Tumors

ClinicalTrials.gov

2014-11-06

Adult Grade III Lymphomatoid Granulomatosis; Adult Nasal Type Extranodal NK/T-cell Lymphoma; AIDS-related Diffuse Large Cell Lymphoma; AIDS-related Diffuse Mixed Cell Lymphoma; AIDS-related Diffuse Small Cleaved Cell Lymphoma; AIDS-related Immunoblastic Large Cell Lymphoma; AIDS-related Lymphoblastic Lymphoma; AIDS-related Peripheral/Systemic Lymphoma; AIDS-related Primary CNS Lymphoma; AIDS-related Small Noncleaved Cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; HER2-negative Breast Cancer; HIV-associated Hodgkin Lymphoma; Intraocular Lymphoma; Male Breast Cancer; Nodal Marginal Zone B-cell Lymphoma; Post-transplant Lymphoproliferative Disorder; Primary Central Nervous System Hodgkin Lymphoma; Primary Central Nervous System Non-Hodgkin Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Adult T-cell Leukemia/Lymphoma; Recurrent Breast Cancer; Recurrent Colon Cancer; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent Rectal Cancer; Recurrent Small Lymphocytic Lymphoma; Small Intestine Lymphoma; Splenic Marginal Zone Lymphoma; Stage III Adult Burkitt Lymphoma; Stage III Adult Diffuse Large Cell Lymphoma; Stage III Adult Diffuse Mixed Cell Lymphoma; Stage III Adult Diffuse Small Cleaved Cell Lymphoma; Stage III Adult Hodgkin Lymphoma; Stage III Adult Immunoblastic

Protein kinase C-beta inhibition induces apoptosis and inhibits cell cycle progression in AIDS-related Non-Hodgkin lymphoma cells

PubMed Central

Saba, Nakhle S.; Levy, Laura S.

2011-01-01

AIDS-related Non-Hodgkin Lymphoma (AIDS-NHL) constitutes an aggressive variety of lymphomas characterized by increased extranodal involvement, relapse rate and resistance to chemotherapy. PKCβ targeting showed promising results in preclinical and clinical studies involving a wide variety of cancers, but studies describing the role of PKCβ in AIDS-NHL are primitive if not lacking. In the present study, three AIDS-NHL cell lines were examined: 2F7 (AIDS-Burkitt Lymphoma), BCBL-1 (AIDS-Primary Effusion Lymphoma) and UMCL01-101 (AIDS-Diffuse Large B Cell Lymphoma). Immunoblot analysis demonstrated expression of PKCβ1 and PKCβ2 in 2F7 and UMCL01-101 cells, and PKCβ1 alone in BCBL-1 cells. The viability of 2F7 and BCBL-1 cells decreased significantly in the presence of PKCβ-selective inhibitor at IC50 of 14 μM and 15 μM, respectively, as measured by MTS assay. In contrast, UMCL01-101 cells were relatively resistant. As determined using flow cytometric TUNEL assay with propidium iodide staining, the responsiveness of sensitive cells was associated with apoptotic induction and cell cycle inhibition. PKCβ-selective inhibition was observed not to affect AKT phosphorylation, but to induce a rapid and sustained reduction in the phosphorylation of GSK3β, ribosomal protein S6, and mTOR in sensitive cell lines. The results indicate that PKCβ plays an important role in AIDS-related NHL survival, and suggest that PKCβ targeting should be considered in a broader spectrum of NHL. The observations in BCBL-1 were unexpected in the absence of PKCβ2 expression and implicate PKCβ1 as a regulator in those cells. PMID:21997316

Double-diffusive layers in the Adriatic Sea

NASA Astrophysics Data System (ADS)

Carniel, Sandro; Sclavo, Mauro; Kantha, Lakshmi; Prandke, Hartmut

2008-01-01

A microstructure profiler was deployed to make turbulence measurements in the upper layers of the southern Adriatic Sea in the Mediterranean during the Naval Research Laboratory (NRL) DART06A (Dynamics of the Adriatic in Real Time) winter cruise in March 2006. Measurements in the Po river plume along the Italian coast near the Gargano promontory displayed classic double-diffusive layers and staircase structures resulting from the relatively colder and fresher wintertime Po river outflow water masses overlying warmer and more saline water masses from the Adriatic Sea. We report here on the water mass and turbulence structure measurements made both in the double-diffusive interfaces and the adjoining mixed layers in the water columns undergoing double-diffusive convection (DDC). This dataset augments the relatively sparse observations available hitherto on the diffusive layer type of DDC. Measured turbulence diffusivities are consistent with those from earlier theoretical and experimental formulations, suggesting that the wintertime Po river plume is a convenient and easily accessible place to study double diffusive convective processes of importance to mixing in the interior of many regions of the global oceans.

Diffusive tunneling for alleviating Knudsen-layer reactivity reduction under hydrodynamic mix

NASA Astrophysics Data System (ADS)

Tang, Xianzhu; McDevitt, Chris; Guo, Zehua

2017-10-01

Hydrodynamic mix will produce small features for intermixed deuterium-tritium fuel and inert pusher materials. The geometrical characteristics of the mix feature have a large impact on Knudsen layer yield reduction. We considered two features. One is planar structure, and the other is fuel cells segmented by inert pusher material which can be represented by a spherical DT bubble enclosed by a pusher shell. The truly 3D fuel feature, the spherical bubble, has the largest degree of yield reduction, due to fast ions being lost in all directions. The planar fuel structure, which can be regarded as 1D features, has modest amount of potential for yield degradation. While the increasing yield reduction with increasing Knudsen number of the fuel region is straightforwardly anticipated, we also show, by a combination of direct simulation and simple model, that once the pusher materials is stretched sufficiently thin by hydrodynamic mix, the fast fuel ions diffusively tunnel through them with minimal energy loss, so the Knudsen layer yield reduction becomes alleviated. This yield recovery can occur in a chunk-mixed plasma, way before the far more stringent, asymptotic limit of an atomically homogenized fuel and pusher assembly. Work supported by LANL LDRD program.

Measurements of exciton diffusion by degenerate four-wave mixing in CdS1-xSex

NASA Astrophysics Data System (ADS)

Schwab, H.; Pantke, K.-H.; Hvam, J. M.; Klingshirn, C.

1992-09-01

We performed transient-grating experiments to study the diffusion of excitons in CdS1-xSex mixed crystals. The decay of the initially created exciton density grating is well described for t<=1 ns by a stretched-exponential function. For later times this decay changes over to a behavior that is well fitted by a simple exponential function. During resonant excitation of the localized states, we find the diffusion coefficient (D) to be considerably smaller than in the binary compounds CdSe and CdS. At 4.2 K, D is below our experimental resolution which is about 0.025 cm2/s. With increasing lattice temperature (Tlattice) the diffusion coefficient increases. It was therefore possible to prove, in a diffusion experiment, that at Tlattice<=5 K the excitons are localized, while the exciton-phonon interaction leads to a delocalization and thus to the onset of diffusion. It was possible to deduce the diffusion coefficient of the extended excitons as well as the energetic position of the mobility edge.

Changes in the influence of lymphoma- and HIV-specific factors on outcomes in AIDS-related non-Hodgkin lymphoma

PubMed Central

Barta, S. K.; Samuel, M. S.; Xue, X.; Wang, D.; Lee, J. Y.; Mounier, N.; Ribera, J.-M.; Spina, M.; Tirelli, U.; Weiss, R.; Galicier, L.; Boue, F.; Little, R. F.; Dunleavy, K.; Wilson, W. H.; Wyen, C.; Remick, S. C.; Kaplan, L. D.; Ratner, L.; Noy, A.; Sparano, J. A.

2015-01-01

Background We undertook the present analysis to examine the shifting influence of prognostic factors in HIV-positive patients diagnosed with aggressive non-Hodgkin lymphoma (NHL) over the last two decades. Patients and methods We carried out a pooled analysis from an existing database of patients with AIDS-related lymphoma. Individual patient data had been obtained prior from prospective phase II or III clinical trials carried out between 1990 until 2010 in North America and Europe that studied chemo(immuno)therapy in HIV-positive patients diagnosed with AIDS-related lymphomas. Studies had been identified by a systematic review. We analyzed patient-level data for 1546 patients with AIDS-related lymphomas using logistic regression and Cox proportional hazard models to identify the association of patient-, lymphoma-, and HIV-specific variables with the outcomes complete response (CR), progression-free survival, and overall survival (OS) in different eras: pre-cART (1989–1995), early cART (1996–2000), recent cART (2001–2004), and contemporary cART era (2005–2010). Results Outcomes for patients with AIDS-related diffuse large B-cell lymphoma and Burkitt lymphoma improved significantly over time, irrespective of baseline CD4 count or age-adjusted International Prognostic Index (IPI) risk category. Two-year OS was best in the contemporary era: 67% and 75% compared with 24% and 37% in the pre-cART era (P < 0.001). While the age-adjusted IPI was a significant predictor of outcome in all time periods, the influence of other factors waxed and waned. Individual HIV-related factors such as low CD4 counts (<50/mm3) and prior history of AIDS were no longer associated with poor outcomes in the contemporary era. Conclusions Our results demonstrate a significant improvement of CR rate and survival for all patients with AIDS-related lymphomas. Effective HIV-directed therapies reduce the impact of HIV-related prognostic factors on outcomes and allow curative antilymphoma

Oxygen diffusion model of the mixed (U,Pu)O2 ± x: Assessment and application

NASA Astrophysics Data System (ADS)

Moore, Emily; Guéneau, Christine; Crocombette, Jean-Paul

2017-03-01

The uranium-plutonium (U,Pu)O2 ± x mixed oxide (MOX) is used as a nuclear fuel in some light water reactors and considered for future reactor generations. To gain insight into fuel restructuring, which occurs during the fuel lifetime as well as possible accident scenarios understanding of the thermodynamic and kinetic behavior is crucial. A comprehensive evaluation of thermo-kinetic properties is incorporated in a computational CALPHAD type model. The present DICTRA based model describes oxygen diffusion across the whole range of plutonium, uranium and oxygen compositions and temperatures by incorporating vacancy and interstitial migration pathways for oxygen. The self and chemical diffusion coefficients are assessed for the binary UO2 ± x and PuO2 - x systems and the description is extended to the ternary mixed oxide (U,Pu)O2 ± x by extrapolation. A simulation to validate the applicability of this model is considered.

Diffuse reflectance relations based on diffusion dipole theory for large absorption and reduced scattering

NASA Astrophysics Data System (ADS)

Bremmer, Rolf H.; van Gemert, Martin J. C.; Faber, Dirk J.; van Leeuwen, Ton G.; Aalders, Maurice C. G.

2013-08-01

Diffuse reflectance spectra are used to determine the optical properties of biological samples. In medicine and forensic science, the turbid objects under study often possess large absorption and/or scattering properties. However, data analysis is frequently based on the diffusion approximation to the radiative transfer equation, implying that it is limited to tissues where the reduced scattering coefficient dominates over the absorption coefficient. Nevertheless, up to absorption coefficients of 20 m at reduced scattering coefficients of 1 and 11.5 mm-1, we observed excellent agreement (r2=0.994) between reflectance measurements of phantoms and the diffuse reflectance equation proposed by Zonios et al. [Appl. Opt. 38, 6628-6637 (1999)], derived as an approximation to one of the diffusion dipole equations of Farrell et al. [Med. Phys. 19, 879-888 (1992)]. However, two parameters were fitted to all phantom experiments, including strongly absorbing samples, implying that the reflectance equation differs from diffusion theory. Yet, the exact diffusion dipole approximation at high reduced scattering and absorption also showed agreement with the phantom measurements. The mathematical structure of the diffuse reflectance relation used, derived by Zonios et al. [Appl. Opt. 38, 6628-6637 (1999)], explains this observation. In conclusion, diffuse reflectance relations derived as an approximation to the diffusion dipole theory of Farrell et al. can analyze reflectance ratios accurately, even for much larger absorption than reduced scattering coefficients. This allows calibration of fiber-probe set-ups so that the object's diffuse reflectance can be related to its absorption even when large. These findings will greatly expand the application of diffuse reflection spectroscopy. In medicine, it may allow the use of blue/green wavelengths and measurements on whole blood, and in forensic science, it may allow inclusion of objects such as

Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

NASA Astrophysics Data System (ADS)

Watanabe, T.; Nagata, K.

2016-08-01

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting a value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES-LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.

Care Aides' Relational Practices and Caring Contributions.

PubMed

Andersen, Elizabeth A; Spiers, Jude

2016-11-01

HOW TO OBTAIN CONTACT HOURS BY READING THIS ARTICLE INSTRUCTIONS 1.2 contact hours will be awarded by Villanova University College of Nursing upon successful completion of this activity. A contact hour is a unit of measurement that denotes 60 minutes of an organized learning activity. This is a learner-based activity. Villanova University College of Nursing does not require submission of your answers to the quiz. A contact hour certificate will be awarded once you register, pay the registration fee, and complete the evaluation form online at http://goo.gl/gMfXaf. To obtain contact hours you must: 1. Read the article, "Care Aides' Relational Practices and Caring Contributions" found on pages 24-30, carefully noting any tables and other illustrative materials that are included to enhance your knowledge and understanding of the content. Be sure to keep track of the amount of time (number of minutes) you spend reading the article and completing the quiz. 2. Read and answer each question on the quiz. After completing all of the questions, compare your answers to those provided within this issue. If you have incorrect answers, return to the article for further study. 3. Go to the Villanova website listed above to register for contact hour credit. You will be asked to provide your name; contact information; and a VISA, MasterCard, or Discover card number for payment of the $20.00 fee. Once you complete the online evaluation, a certificate will be automatically generated. This activity is valid for continuing education credit until October 31, 2019. CONTACT HOURS This activity is co-provided by Villanova University College of Nursing and SLACK Incorporated. Villanova University College of Nursing is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation. ACTIVITY OBJECTIVES 1. Define the application of Swanson's Middle Range Theory of Caring in care aides' relational care practices for nursing home

Diffusibility Enhancement of Rejuvenator by Epoxidized Soybean Oil and Its Influence on the Performance of Recycled Hot Mix Asphalt Mixtures

PubMed Central

Kuang, Dongliang; Jiao, Yuan; Ye, Zhou; Lu, Zaihong; Chen, Huaxin; Yu, Jianying; liu, Ning

2018-01-01

Epoxidized soybean oil (ESO) was employed as a novel penetrant cooperating with a conventional rejuvenator (CR) for the recycling of reclaimed asphalt pavement (RAP). The influence of ESO on the diffusibility and the regenerating effects of CR on RAP were investigated. The diffusibility testing result shows that the diffusibility of CR is enhanced by the addition of ESO because the epoxy group in ESO can facilitate asphaltene dispersion due to its high polarity, which simultaneously reduces the viscosity and improves the fluidity of aged bitumen so as to allow diffusion of the rejuvenator into the aged bitumen. Road performance testing of a recycled hot mix asphalt mixture (RHMA) indicates that the fatigue and cracking resistance properties as well as the water stability of RHMA containing CR can be improved by the addition of ESO due to the diffusibility enhancement of CR, which boosts the regenerating effect of CR on aged bitumen in RAP. The fatigue and cracking resistance properties as well as the water stability of the recycled hot mix asphalt mixture containing CR with 7 wt % ESO approximate those of the hot mix asphalt mixture composed of the same virgin aggregates and bitumen. Taking into account the rutting resistance decline versus the addition of ESO, the content of ESO should not exceed 7 wt % of the conventional rejuvenator. PMID:29783675

Diffusibility Enhancement of Rejuvenator by Epoxidized Soybean Oil and Its Influence on the Performance of Recycled Hot Mix Asphalt Mixtures.

PubMed

Kuang, Dongliang; Jiao, Yuan; Ye, Zhou; Lu, Zaihong; Chen, Huaxin; Yu, Jianying; Liu, Ning

2018-05-18

Epoxidized soybean oil (ESO) was employed as a novel penetrant cooperating with a conventional rejuvenator (CR) for the recycling of reclaimed asphalt pavement (RAP). The influence of ESO on the diffusibility and the regenerating effects of CR on RAP were investigated. The diffusibility testing result shows that the diffusibility of CR is enhanced by the addition of ESO because the epoxy group in ESO can facilitate asphaltene dispersion due to its high polarity, which simultaneously reduces the viscosity and improves the fluidity of aged bitumen so as to allow diffusion of the rejuvenator into the aged bitumen. Road performance testing of a recycled hot mix asphalt mixture (RHMA) indicates that the fatigue and cracking resistance properties as well as the water stability of RHMA containing CR can be improved by the addition of ESO due to the diffusibility enhancement of CR, which boosts the regenerating effect of CR on aged bitumen in RAP. The fatigue and cracking resistance properties as well as the water stability of the recycled hot mix asphalt mixture containing CR with 7 wt % ESO approximate those of the hot mix asphalt mixture composed of the same virgin aggregates and bitumen. Taking into account the rutting resistance decline versus the addition of ESO, the content of ESO should not exceed 7 wt % of the conventional rejuvenator.

Disease-related stigma: comparing predictors of AIDS and cancer stigma.

PubMed

Greene, Kathryn; Banerjee, Smita C

2006-01-01

This study explores the prevalence of AIDS and cancer stigma as influenced by attitude toward homosexuality, religiosity, authoritarianism, and androgyny. This study used a quasi-experimental survey design (N = 485) to examine attitude toward people with AIDS and cancer, and interaction with people with AIDS and cancer. Negative attitudes toward homosexuality, high religious intensity and ideology, high authoritarianism, and low expressive emerged as factors related to more negative attitudes toward people with AIDS and unwillingness to interact with people with AIDS. Attitudes toward people with cancer were generally not related to the variables. Findings explore how to campaign efforts to reduce existing negative attitudes toward AIDS and homosexuality, given that gay men with AIDS are especially stigmatized. Implications and directions for future research are discussed, especially for interventions.

Diffusion in the special theory of relativity.

PubMed

Herrmann, Joachim

2009-11-01

The Markovian diffusion theory is generalized within the framework of the special theory of relativity. Since the velocity space in relativity is a hyperboloid, the mathematical stochastic calculus on Riemanian manifolds can be applied but adopted here to the velocity space. A generalized Langevin equation in the fiber space of position, velocity, and orthonormal velocity frames is defined from which the generalized relativistic Kramers equation in the phase space in external force fields is derived. The obtained diffusion equation is invariant under Lorentz transformations and its stationary solution is given by the Jüttner distribution. Besides, a nonstationary analytical solution is derived for the example of force-free relativistic diffusion.

AIDS-related and non-AIDS-related mortality in the Asia-Pacific region in the era of combination antiretroviral treatment.

PubMed

Falster, Kathleen; Choi, Jun Yong; Donovan, Basil; Duncombe, Chris; Mulhall, Brian; Sowden, David; Zhou, Jialun; Law, Matthew G

2009-11-13

Although studies have shown reductions in mortality from AIDS after the introduction of combination antiretroviral treatment (cART), little is known about cause-specific mortality in low-income settings in the cART era. We explored predictors of AIDS and non-AIDS mortality and compared cause-specific mortality across high-income and low-income settings in the Asia-Pacific region. We followed patients in the Asia Pacific HIV Observational Database from the date they started cART (or cohort enrolment if cART initiation was identified retrospectively), until the date of death or last follow-up visit. Competing risks methods were used to estimate the cumulative incidence, and to investigate predictors, of AIDS and non-AIDS mortality. Of 4252 patients, 215 died; 89 from AIDS, 97 from non-AIDS causes and 29 from unknown causes. Age more than 50 years [hazard ratio 4.29; 95% confidence interval (CI) 2.10-8.79] and CD4 cell counts less than or equal to 100 cells/microl (hazard ratio 8.59; 95% CI 5.66-13.03) were associated with an increased risk of non-AIDS mortality. Risk factors for AIDS mortality included CD4 cell counts less than or equal to 100 cells/microl (hazard ratio 34.97; 95% CI 18.01-67.90) and HIV RNA 10 001 or more (hazard ratio 4.21; 95% CI 2.07-8.55). There was some indication of a lower risk of non-AIDS mortality in Asian high-income, and possibly low-income, countries compared to Australia. Immune deficiency is associated with an increased risk of AIDS and non-AIDS mortality. Older age predicts non-AIDS mortality in the cART era. Less conclusive was the association between country-income level and cause-specific mortality because of the relatively high proportion of unknown causes of death in low-income settings.

Electron Energization and Mixing Observed by MMS in the Vicinity of an Electron Diffusion Region During Magnetopause Reconnection

NASA Technical Reports Server (NTRS)

Chen, Li-Jen; Hesse, Michael; Wang, Shan; Gershman, Daniel; Ergun, Robert; Pollock, Craig; Torbert, Roy; Bessho, Naoki; Daughton, William; Dorelli, John;

Electron energization and mixing observed by MMS in the vicinity of an electron diffusion region during magnetopause reconnection

NASA Astrophysics Data System (ADS)

Chen, Li-Jen; Hesse, Michael; Wang, Shan; Gershman, Daniel; Ergun, Robert; Pollock, Craig; Torbert, Roy; Bessho, Naoki; Daughton, William; Dorelli, John; Giles, Barbara; Strangeway, Robert; Russell, Christopher; Khotyaintsev, Yuri; Burch, Jim; Moore, Thomas; Lavraud, Benoit; Phan, Tai; Avanov, Levon

2016-06-01

Measurements from the Magnetospheric Multiscale (MMS) mission are reported to show distinct features of electron energization and mixing in the diffusion region of the terrestrial magnetopause reconnection. At the ion jet and magnetic field reversals, distribution functions exhibiting signatures of accelerated meandering electrons are observed at an electron out-of-plane flow peak. The meandering signatures manifested as triangular and crescent structures are established features of the electron diffusion region (EDR). Effects of meandering electrons on the electric field normal to the reconnection layer are detected. Parallel acceleration and mixing of the inflowing electrons with exhaust electrons shape the exhaust flow pattern. In the EDR vicinity, the measured distribution functions indicate that locally, the electron energization and mixing physics is captured by two-dimensional reconnection, yet to account for the simultaneous four-point measurements, translational invariant in the third dimension must be violated on the ion-skin-depth scale.

IGO-NGO relations and HIV / AIDS: innovation or stalemate?

PubMed

Jonsson, C; Soderholm, P

1995-01-01

This paper is concerned with the emergence of transnational cooperative structures in response to AIDS. Of chief concern are efforts to create and maintain links among and between intergovernmental organizations (IGO) in the UN system and the many heterogenous organizations usually included under the nongovernmental organization (NGO) label. After discussing the nature of the AIDS issue, the authors focus upon the various ways of framing the AIDS issue and the effort by the Global Program on AIDS to coordinate IGO and NGO activities. In closing, they identify lessons and insights of broader applicability emanating from the AIDS case. The paper discusses the nature of AIDS, AIDS as a medical problem, AIDS as a human rights problem, AIDS as a socioeconomic problem, forging IGO-NGO links, an international NGO forum, informal networking, NGOs and AIDS-related foreign assistance, representation, formal versus informal coordination, costs of network building, degree of organization, and expertise.

Professionalisation and social attitudes: a protocol for measuring changes in HIV/AIDS-related stigma among healthcare students

PubMed Central

Ahmadi, Keivan; Reidpath, Daniel D; Allotey, Pascale; Hassali, Mohamed Azmi Ahmad

2013-01-01

Introduction HIV/AIDS-related stigma affects the access and utilisation of health services. Although HIV/AIDS-related stigma in the health services has been studied, little work has attended to the relationship between professional development and stigmatising attitudes. Hence, in this study, we will extend earlier research by examining the relationship between the stage of professional development and the kinds of stigmatising attitudes held about people living with HIV/AIDS. Methods and analysis A serial cross-sectional design will be combined with a two-point in time longitudinal design to measure the levels of stigma among healthcare students from each year of undergraduate and graduate courses in Malaysia and Australia. In the absence of suitable measures, we will carry out a sequential mixed methods design to develop such a tool. The questionnaire data will be analysed using mixed effects linear models to manage the repeated measures. Ethics and dissemination We have received ethical approval from the Monash MBBS executive committee as well as the Monash University Human Research Ethics Committee. We will keep the data in a locked filing cabinet in the Monash University (Sunway campus) premises for 5 years, after which the information will be shredded and disposed of in secure bins, and digital recordings will be erased in accordance with Monash University's regulations. Only the principal investigator and the researcher will have access to the filing cabinet. We aim to present and publish the results of this study in national and international conferences and peer-reviewed journals, respectively. PMID:23793653

Calculation method for steady-state pollutant concentration in mixing zones considering variable lateral diffusion coefficient.

PubMed

Wu, Wen; Wu, Zhouhu; Song, Zhiwen

2017-07-01

Prediction of the pollutant mixing zone (PMZ) near the discharge outfall in Huangshaxi shows large error when using the methods based on the constant lateral diffusion assumption. The discrepancy is due to the lack of consideration of the diffusion coefficient variation. The variable lateral diffusion coefficient is proposed to be a function of the longitudinal distance from the outfall. Analytical solution of the two-dimensional advection-diffusion equation of a pollutant is derived and discussed. Formulas to characterize the geometry of the PMZ are derived based on this solution, and a standard curve describing the boundary of the PMZ is obtained by proper choices of the normalization scales. The change of PMZ topology due to the variable diffusion coefficient is then discussed using these formulas. The criterion of assuming the lateral diffusion coefficient to be constant without large error in PMZ geometry is found. It is also demonstrated how to use these analytical formulas in the inverse problems including estimating the lateral diffusion coefficient in rivers by convenient measurements, and determining the maximum allowable discharge load based on the limitations of the geometrical scales of the PMZ. Finally, applications of the obtained formulas to onsite PMZ measurements in Huangshaxi present excellent agreement.

Mixing model with multi-particle interactions for Lagrangian simulations of turbulent mixing

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

Watanabe, T., E-mail: watanabe.tomoaki@c.nagoya-u.jp; Nagata, K.

We report on the numerical study of the mixing volume model (MVM) for molecular diffusion in Lagrangian simulations of turbulent mixing problems. The MVM is based on the multi-particle interaction in a finite volume (mixing volume). A priori test of the MVM, based on the direct numerical simulations of planar jets, is conducted in the turbulent region and the interfacial layer between the turbulent and non-turbulent fluids. The results show that the MVM predicts well the mean effects of the molecular diffusion under various numerical and flow parameters. The number of the mixing particles should be large for predicting amore » value of the molecular diffusion term positively correlated to the exact value. The size of the mixing volume relative to the Kolmogorov scale η is important in the performance of the MVM. The scalar transfer across the turbulent/non-turbulent interface is well captured by the MVM especially with the small mixing volume. Furthermore, the MVM with multiple mixing particles is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (LES–LPS) of the planar jet with the characteristic length of the mixing volume of O(100η). Despite the large mixing volume, the MVM works well and decays the scalar variance in a rate close to the reference LES. The statistics in the LPS are very robust to the number of the particles used in the simulations and the computational grid size of the LES. Both in the turbulent core region and the intermittent region, the LPS predicts a scalar field well correlated to the LES.« less

"Mixing" as an ethnoetiology of HIV/AIDS in Malaysia's multinational factories.

PubMed

Root, Robin

2006-09-01

Minah Karan, the stigmatizing label appended to Malay factory women in the 1980s, signaled a dangerous female sexuality that risked spreading beyond the factory gates and infecting Malaysia's idea(l)s of its traditional kampung culture. This article narrates how Minah Karan, as the former antihero of development, was reconstituted in the 1990s, with the government's labeling of factories as "high-risk settings" for HIV/AIDS. This is an ethnoetiology based not on any evidential epidemiological data but on the racial and gendered "mixing" that transpires behind factory walls: a fear that the "mixing of the sexes" means ipso facto "sexual mixing" among the races. The article demonstrates how importation of the high-risk label articulates at the local level the new and contested linkages, economic, religious, and scientific, constitutive of globalization. The pragmatic nature and imperatives of this high-risk process are discerned in factory women's accounts of how they negotiate the interactional imperatives of factory work, because transnational structures of productivity violate the social boundaries that have long connoted political stability, moral integrity, ethnic community, and individual safety. The article concludes by questioning whether ethnoetiologies, especially when they concern sexual networks, become social etiologies, because this would locate ethnoetiologies as central to conventional public health praxis rather than as ethnographic exotica in the margins.

Adolescents' Thoughts and Feelings about AIDS in Relation to Cognitive Maturity.

ERIC Educational Resources Information Center

Peterson, Candida C.; Murphy, Lisa

1990-01-01

Studied adolescents' (N=163) formal operational reasoning in relation to Acquired Immune Deficiency Syndrome (AIDS) knowledge, AIDS fear, sexual knowledge, and reactions to AIDS victims. Found that advanced reasoning predicted better AIDS knowledge and general sexual knowledge. Advanced reasoning and AIDS knowledge were also linked with heightened…

Atomic diffusion and mixing in old stars. V. A deeper look into the globular cluster NGC 6752

NASA Astrophysics Data System (ADS)

Gruyters, Pieter; Nordlander, Thomas; Korn, Andreas J.

2014-07-01

Context. Abundance trends in heavier elements with evolutionary phase have been shown to exist in the globular cluster NGC 6752 ([Fe / H] = -1.6). These trends are a result of atomic diffusion and additional (non-convective) mixing. Studying such trends can provide us with important constraints on the extent to which diffusion modifies the internal structure and surface abundances of solar-type, metal-poor stars. Aims: Taking advantage of a larger data sample, we investigate the reality and the size of these abundance trends and address questions and potential biases associated with the various stellar populations that make up NGC 6752. Methods: We perform an abundance analysis by combining photometric and spectroscopic data of 194 stars located between the turnoff point and the base of the red giant branch. Stellar parameters are derived from uvby Strömgren photometry. Using the quantitative-spectroscopy package SME, stellar surface abundances for light elements such as Li, Na, Mg, Al, and Si as well as heavier elements such as Ca, Ti, and Fe are derived in an automated way by fitting synthetic spectra to individual lines in the stellar spectra, obtained with the VLT/FLAMES-GIRAFFE spectrograph. Results: Based on uvby Strömgren photometry, we are able to separate three stellar populations in NGC 6752 along the evolutionary sequence from the base of the red giant branch down to the turnoff point. We find weak systematic abundance trends with evolutionary phase for Ca, Ti, and Fe which are best explained by stellar-structure models including atomic diffusion with efficient additional mixing. We derive a new value for the initial lithium abundance of NGC 6752 after correcting for the effect of atomic diffusion and additional mixing which falls slightly below the predicted standard BBN value. Conclusions: We find three stellar populations by combining photometric and spectroscopic data of 194 stars in the globular cluster NGC 6752. Abundance trends for groups of

Clouding tracing: Visualization of the mixing of fluid elements in convection-diffusion systems

NASA Technical Reports Server (NTRS)

Ma, Kwan-Liu; Smith, Philip J.

1993-01-01

This paper describes a highly interactive method for computer visualization of the basic physical process of dispersion and mixing of fluid elements in convection-diffusion systems. It is based on transforming the vector field from a traditionally Eulerian reference frame into a Lagrangian reference frame. Fluid elements are traced through the vector field for the mean path as well as the statistical dispersion of the fluid elements about the mean position by using added scalar information about the root mean square value of the vector field and its Lagrangian time scale. In this way, clouds of fluid elements are traced and are not just mean paths. We have used this method to visualize the simulation of an industrial incinerator to help identify mechanisms for poor mixing.

Diffuse colonies of human skin fibroblasts in relation to cellular senescence and proliferation.

PubMed

Zorin, Vadim; Zorina, Alla; Smetanina, Nadezhda; Kopnin, Pavel; Ozerov, Ivan V; Leonov, Sergey; Isaev, Artur; Klokov, Dmitry; Osipov, Andreyan N

2017-05-16

Development of personalized skin treatment in medicine and skin care may benefit from simple and accurate evaluation of the fraction of senescent skin fibroblasts that lost their proliferative capacity. We examined whether enriched analysis of colonies formed by primary human skin fibroblasts, a simple and widely available cellular assay, could reveal correlations with the fraction of senescent cells in heterogenic cell population. We measured fractions of senescence associated β-galactosidase (SA-βgal) positive cells in either mass cultures or colonies of various morphological types (dense, mixed and diffuse) formed by skin fibroblasts from 10 human donors. Although the donors were chosen to be within the same age group (33-54 years), the colony forming efficiency of their fibroblasts (ECO-f) and the percentage of dense, mixed and diffuse colonies varied greatly among the donors. We showed, for the first time, that the SA-βgal positive fraction was the largest in diffuse colonies, confirming that they originated from cells with the least proliferative capacity. The percentage of diffuse colonies was also found to correlate with the SA-βgal positive cells in mass culture. Using Ki67 as a cell proliferation marker, we further demonstrated a strong inverse correlation (r=-0.85, p=0.02) between the percentage of diffuse colonies and the fraction of Ki67+ cells. Moreover, a significant inverse correlation (r=-0.94, p=0.0001) between the percentage of diffuse colonies and ECO-f was found. Our data indicate that quantification of a fraction of diffuse colonies may provide a simple and useful method to evaluate the extent of cellular senescence in human skin fibroblasts.

Diffusive mixing and Tsallis entropy

DOE PAGES

O'Malley, Daniel; Vesselinov, Velimir V.; Cushman, John H.

2015-04-29

Brownian motion, the classical diffusive process, maximizes the Boltzmann-Gibbs entropy. The Tsallis q-entropy, which is non-additive, was developed as an alternative to the classical entropy for systems which are non-ergodic. A generalization of Brownian motion is provided that maximizes the Tsallis entropy rather than the Boltzmann-Gibbs entropy. This process is driven by a Brownian measure with a random diffusion coefficient. In addition, the distribution of this coefficient is derived as a function of q for 1 < q < 3. Applications to transport in porous media are considered.

Photoletter to the editor: Diffuse cocaine-related purpura.

PubMed

Sarkar, Debjeet; Kammona, Hussein A; Lamsen, Leonard N; McAbee, Bradley A; Clark, Christopher T; Lee, Solomon S; Kelley, Shane E

2013-01-01

Diffuse purpura is an uncommon skin manifestation found in platelet and coagulation disorders, meningococcemia, vasculitides and cocaine use. Reports of cocaine-related purpura predominantly involve adulteration with the anti-helminthic, levamisole. Levamisole enhances the effects of cocaine and is known to cause vasculitis. Recently, the CDC also released an advisory of oxymorphone being used intravenously causing thrombogenic thrombocytopenic purpura (TTP). We report the case of a patient with diffuse purpura ultimately diagnosed with cocaine-related thrombogenic vasculopathy. In the current environment of adulterated cocaine usage and increased prescription narcotic abuse, it is crucial to investigate substance abuse as a cause of diffuse purpura.

Electro-diffusion in a plasma with two ion species

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

Kagan, Grigory; Tang Xianzhu

2012-08-15

Electric field is a thermodynamic force that can drive collisional inter-ion-species transport in a multicomponent plasma. In an inertial confinement fusion capsule, such transport causes fuel ion separation even with a target initially prepared to have equal number densities for the two fuel ion species. Unlike the baro-diffusion driven by ion pressure gradient and the thermo-diffusion driven by ion and electron temperature gradients, electro-diffusion has a critical dependence on the charge-to-mass ratio of the ion species. Specifically, it is shown here that electro-diffusion vanishes if the ion species have the same charge-to-mass ratio. An explicit expression for the electro-diffusion ratiomore » is obtained and used to investigate the relative importance of electro- and baro-diffusion mechanisms. In particular, it is found that electro-diffusion reinforces baro-diffusion in the deuterium and tritium mix, but tends to cancel it in the deuterium and helium-3 mix.« less

Challenges in fitting a hearing aid to a severely collapsed ear canal and mixed hearing loss.

PubMed

Oeding, Kristi; Valente, Michael; Chole, Richard

2012-04-01

Collapsed ear canals typically occur when an outside force, such as a headset for audiometric testing, is present. However, when a collapsed ear canal occurs without external pressure, this creates a challenge not only for performing audiometric testing but also for coupling a hearing aid to the ear canal. This case report highlights the challenges associated with fitting a hearing aid on a patient with a severe anterior-posterior collapsed ear canal with a mixed hearing loss. A 67-yr-old female originally presented to Washington University in St. Louis School of Medicine in 1996 with a long-standing history of bilateral otosclerosis. She had chronic ear infections in the right ear and a severely collapsed ear canal in the left ear and was fit with a bone anchored hearing aid (BAHA®) on the right side in 2003. However, benefit from the BAHA started to decrease due to changes in hearing, and a different hearing solution was needed. It was proposed that a hearing aid be fit to her collapsed left ear canal; however, trying to couple a hearing aid to the collapsed ear canal required unique noncustom earmold solutions. This case study highlights some of the obstacles and potential solutions for coupling a hearing aid to a severely collapsed ear canal. American Academy of Audiology.

A diffuse mixed histiocytic-lymphocytic lymphoma associated with immunological abnormalities.

PubMed

Syrjänen, K J

1979-01-01

A diffuse generalized lymphoma histologically classified as mixed histiocytic-lymphocytic type and associated with profound immunologie abnormalities is reported. The patient had an autoimmune hemolytic anemia, an autoimmune thrombocytopenia, polyclonally increased IgG and IgM, polyclonal secretion of kappa and lamda chains into urine, very low serum complement C3 and antibodies against glomerulus and smooth muscle. When studied with the modern surface-marker techniques, the lesion was found to be composed of entirely lymphoid cells of the B-lymphocyte series. The proper classification of this tumor could be a primitive immunoblastic sarcoma. The relationship of the present tumor to the non-neoplastic angioimmunoblastic lymphadenopathia is discussed. The necessity of applying the surface-marker techniques in the classification of malignant lymphomas is emphasized.

Mixed-order phase transition in a minimal, diffusion-based spin model.

PubMed

Fronczak, Agata; Fronczak, Piotr

2016-07-01

In this paper we exactly solve, within the grand canonical ensemble, a minimal spin model with the hybrid phase transition. We call the model diffusion based because its Hamiltonian can be recovered from a simple dynamic procedure, which can be seen as an equilibrium statistical mechanics representation of a biased random walk. We outline the derivation of the phase diagram of the model, in which the triple point has the hallmarks of the hybrid transition: discontinuity in the average magnetization and algebraically diverging susceptibilities. At this point, two second-order transition curves meet in equilibrium with the first-order curve, resulting in a prototypical mixed-order behavior.

Molecular dynamics insights into the structural and diffusive properties of ZIF-8/PDMS mixed matrix membranes in the n-butanol/water pervaporation process

NASA Astrophysics Data System (ADS)

Sun, Tao; Fang, Manquan; Wu, Zhen; Yu, Lixin; Li, Jiding

2017-04-01

Molecular dynamics (MD) simulation was used to study the structural and diffusive properties of zeolitic imidazolate framework-8 (ZIF-8)/polydimethylsiloxane (PDMS), a novel alcohol-permselective mixed matrix membrane (MMM). Simulation models of one pure PDMS membrane and three ZIF-8/PDMS MMMs with increasing loadings were successfully constructed. Non-bond energy turned out to be a strong attractive interaction between the PDMS matrix and ZIF-8 cells. The morphology and mobility of PDMS chains were characterized by mean square displacement (MSD). The fraction of free volume (FFV) of the pure membrane and MMMs was calculated and showed declining trends with increasing ZIF-8 loadings. The diffusion coefficients of n-butanol and water molecules were calculated by the Einstein relation. {D}n-\\text{butanol} first increased then decreased, while {D}{{water}} decreased with the increasing loadings. The mechanism of selective diffusion behaviour was investigated and it was found that the inner channels of ZIF-8 provided selective pathways for n-butanol. Diffusion coefficients were correlated with FFV and the results showed that the logarithm of {D}{{water}} demonstrated a good linear relation with the inverse FFV and was in agreement with the free volume theory, while {D}n-\\text{butanol} showed a significant deviation in the case of MMM-1 due to the selective diffusion channels provided by ZIF-8.

Chemical transport models: the combined non-local diffusion and mixing schemes, and calculation of in-canopy resistance for dry deposition fluxes.

PubMed

Mihailovic, Dragutin T; Alapaty, Kiran; Podrascanin, Zorica

2009-03-01

Improving the parameterization of processes in the atmospheric boundary layer (ABL) and surface layer, in air quality and chemical transport models. To do so, an asymmetrical, convective, non-local scheme, with varying upward mixing rates is combined with the non-local, turbulent, kinetic energy scheme for vertical diffusion (COM). For designing it, a function depending on the dimensionless height to the power four in the ABL is suggested, which is empirically derived. Also, we suggested a new method for calculating the in-canopy resistance for dry deposition over a vegetated surface. The upward mixing rate forming the surface layer is parameterized using the sensible heat flux and the friction and convective velocities. Upward mixing rates varying with height are scaled with an amount of turbulent kinetic energy in layer, while the downward mixing rates are derived from mass conservation. The vertical eddy diffusivity is parameterized using the mean turbulent velocity scale that is obtained by the vertical integration within the ABL. In-canopy resistance is calculated by integration of inverse turbulent transfer coefficient inside the canopy from the effective ground roughness length to the canopy source height and, further, from its the canopy height. This combination of schemes provides a less rapid mass transport out of surface layer into other layers, during convective and non-convective periods, than other local and non-local schemes parameterizing mixing processes in the ABL. The suggested method for calculating the in-canopy resistance for calculating the dry deposition over a vegetated surface differs remarkably from the commonly used one, particularly over forest vegetation. In this paper, we studied the performance of a non-local, turbulent, kinetic energy scheme for vertical diffusion combined with a non-local, convective mixing scheme with varying upward mixing in the atmospheric boundary layer (COM) and its impact on the concentration of pollutants

Diffusive exchange of trace elements between basaltic-andesite and dacitic melt: Insights into potential metal fractionation during magma mixing

NASA Astrophysics Data System (ADS)

Fiege, A.; Ruprecht, P.; Simon, A. C.; Holtz, F.

2017-12-01

Mafic magma recharge is a common process that triggers physical and chemical mixing in magmatic systems and drives their evolution, resulting in, e.g., hybridization and volcanic eruptions. Once magma-magma contact is initiated, rapid heat-flux commonly leads to the formation of a cooling-induced crystal mush on the mafic side of the interface. Here, on a local scale (µm to cm), at the magma-magma interface, melt-melt diffusive exchange is required to approach equilibrium. Significant chemical potential gradients drive a complex, multi-element mass flux between the two systems (Liang, 2010). This diffusive-equilibration often controls crystal dissolution rates within the boundary layers and, thus, the formation of interconnected melt or fluid networks. Such networks provide important pathways for the transport of volatiles and trace metals from the mafic recharge magma to the felsic host magma, where the latter may feed volcanic activities and ore deposits. While major element diffusion in silicate melts is mostly well understood, even in complex systems, the available data for many trace element metals are limited (Liang, 2010; Zhang et al., 2010). Differences in diffusivity in a dynamic, mixing environment can cause trace element fractionation, in particular during crystallization and volatile exsolution and separation. This may affect trace element signatures in phenocrysts and magmatic volatile phases that can form near a magma-magma boundary. As a result, the chemistry of volcanic gases and magmatic-hydrothermal ore deposits may be partially controlled by such mixing phenomena. We performed melt-melt diffusion-couple experiments at 150 MPa, 1100°C, FMQ, FMQ+1 and FMQ+3 (FMQ: fayalite-magnetite-quartz oxygen fugacity buffer). Hydrated, sulfur-bearing cylinders of dacite and basaltic andesite were equilibrated for up to 20 h. Major and trace element gradients were measured by using laser-ablation ICP-MS and electron microprobe analyses. The results we will

Computing eddy-driven effective diffusivity using Lagrangian particles

DOE PAGES

Wolfram, Phillip J.; Ringler, Todd D.

2017-08-14

A novel method to derive effective diffusivity from Lagrangian particle trajectory data sets is developed and then analyzed relative to particle-derived meridional diffusivity for eddy-driven mixing in an idealized circumpolar current. Quantitative standard dispersion- and transport-based mixing diagnostics are defined, compared and contrasted to motivate the computation and use of effective diffusivity derived from Lagrangian particles. We compute the effective diffusivity by first performing scalar transport on Lagrangian control areas using stored trajectories computed from online Lagrangian In-situ Global High-performance particle Tracking (LIGHT) using the Model for Prediction Across Scales Ocean (MPAS-O). Furthermore, the Lagrangian scalar transport scheme is comparedmore » against an Eulerian scalar transport scheme. Spatially-variable effective diffusivities are computed from resulting time-varying cumulative concentrations that vary as a function of cumulative area. The transport-based Eulerian and Lagrangian effective diffusivity diagnostics are found to be qualitatively consistent with the dispersion-based diffusivity. All diffusivity estimates show a region of increased subsurface diffusivity within the core of an idealized circumpolar current and results are within a factor of two of each other. The Eulerian and Lagrangian effective diffusivities are most similar; smaller and more spatially diffused values are obtained with the dispersion-based diffusivity computed with particle clusters.« less

Computing eddy-driven effective diffusivity using Lagrangian particles

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

Wolfram, Phillip J.; Ringler, Todd D.

A novel method to derive effective diffusivity from Lagrangian particle trajectory data sets is developed and then analyzed relative to particle-derived meridional diffusivity for eddy-driven mixing in an idealized circumpolar current. Quantitative standard dispersion- and transport-based mixing diagnostics are defined, compared and contrasted to motivate the computation and use of effective diffusivity derived from Lagrangian particles. We compute the effective diffusivity by first performing scalar transport on Lagrangian control areas using stored trajectories computed from online Lagrangian In-situ Global High-performance particle Tracking (LIGHT) using the Model for Prediction Across Scales Ocean (MPAS-O). Furthermore, the Lagrangian scalar transport scheme is comparedmore » against an Eulerian scalar transport scheme. Spatially-variable effective diffusivities are computed from resulting time-varying cumulative concentrations that vary as a function of cumulative area. The transport-based Eulerian and Lagrangian effective diffusivity diagnostics are found to be qualitatively consistent with the dispersion-based diffusivity. All diffusivity estimates show a region of increased subsurface diffusivity within the core of an idealized circumpolar current and results are within a factor of two of each other. The Eulerian and Lagrangian effective diffusivities are most similar; smaller and more spatially diffused values are obtained with the dispersion-based diffusivity computed with particle clusters.« less

Cytokine signaling pathway polymorphisms and AIDS-related non-Hodgkin lymphoma risk in the Multicenter AIDS Cohort Study

PubMed Central

Wong, Hui-Lee; Breen, Elizabeth C.; Pfeiffer, Ruth M.; Aissani, Brahim; Martinson, Jeremy J.; Margolick, Joseph B.; Kaslow, Richard A.; Jacobson, Lisa P.; Ambinder, Richard F.; Chanock, Stephen; Martínez-Maza, Otoniel; Rabkin, Charles S.

2014-01-01

Cytokine stimulation of B-cell proliferation may be an important etiologic mechanism for acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin lymphoma (NHL). The Epstein-Barr virus may be a co-factor, particularly for primary central nervous system (CNS) tumors, which are uniformly EBV-positive in the setting of AIDS. Thus, we examined associations of genetic variation in IL10 and related cytokine signaling molecules (IL10RA, CXCL12, IL13, IL4, IL4R, CCL5 and BCL6) with AIDS-related NHL risk and evaluated differences between primary CNS and systemic tumors. We compared 160 Multicenter AIDS Cohort Study (MACS) participants with incident lymphomas, of which 90 followed another AIDS diagnosis, to HIV-1-seropositive controls matched on duration of lymphoma-free survival post-HIV-1 infection (N=160) or post-AIDS diagnosis (N=90). We fit conditional logistic regression models to estimate odds ratios (ORs) and 95 percent confidence intervals (95%CIs). Carriage of at least one copy of the T allele for the IL10 rs1800871 (as compared to no copies) was associated with decreased AIDS-NHL risk specific to lymphomas arising from the CNS (CC vs. CT/TT: OR=0.3; 95%CI: 0.1, 0.7) but not systemically (CC vs. CT/TT: OR=1.0; 95%CI: 0.5, 1.9) (Pheterogeneity=0.03). Carriage of two copies of the “low IL10” haplotype rs1800896_A/rs1800871_T/rs1800872_A was associated with decreased lymphoma risk that varied by number of copies (Ptrend=0.02). None of the ORs for the other studied polymorphisms was significantly different from 1.0. Excessive IL10 response to HIV-1 infection may be associated with increased risk of NHL, particularly in the CNS. IL10 dysregulation may be an important etiologic pathway for EBV-related lymphomagenesis. PMID:20299965

A new prognostic score for AIDS-related lymphomas in the rituximab-era

PubMed Central

Barta, Stefan K.; Xue, Xiaonan; Wang, Dan; Lee, Jeannette Y.; Kaplan, Lawrence D.; Ribera, Josep-Maria; Oriol, Albert; Spina, Michele; Tirelli, Umberto; Boue, Francois; Wilson, Wyndham H.; Wyen, Christoph; Dunleavy, Kieron; Noy, Ariela; Sparano, Joseph A.

2014-01-01

While the International Prognostic Index is commonly used to predict outcomes in immunocompetent patients with aggressive B-cell non-Hodgkin lymphomas, HIV-infection is an important competing risk for death in patients with AIDS-related lymphomas. We investigated whether a newly created prognostic score (AIDS-related lymphoma International Prognostic Index) could better assess risk of death in patients with AIDS-related lymphomas. We randomly divided a dataset of 487 patients newly diagnosed with AIDS-related lymphomas and treated with rituximab-containing chemoimmunotherapy into a training (n=244) and validation (n=243) set. We examined the association of HIV-related and other known risk factors with overall survival in both sets independently. We defined a new score (AIDS-related lymphoma International Prognostic Index) by assigning weights to each significant predictor [age-adjusted International Prognostic Index, extranodal sites, HIV-score (composed of CD4 count, viral load, and prior history of AIDS)] with three risk categories similar to the age-adjusted International Prognostic Index (low, intermediate and high risk). We compared the prognostic value for overall survival between AIDS-related lymphoma International Prognostic Index and age-adjusted International Prognostic Index in the validation set and found that the AIDS-related lymphoma International Prognostic Index performed significantly better in predicting risk of death than the age-adjusted International Prognostic Index (P=0.004) and better discriminated risk of death between each risk category (P=0.015 vs. P=0.13). Twenty-eight percent of patients were defined as low risk by the ARL-IPI and had an estimated 5-year overall survival (OS) of 78% (52% intermediate risk, 5-year OS 60%; 20% high risk, 5-year OS 50%). PMID:25150257

Generic evolution of mixing in heterogeneous media

NASA Astrophysics Data System (ADS)

De Dreuzy, J.; Carrera, J.; Dentz, M.; Le Borgne, T.

2011-12-01

Mixing in heterogeneous media results from the competition bewteen flow fluctuations and local scale diffusion. Flow fluctuations quickly create concentration contrasts and thus heterogeneity of the concentration field, which is slowly homogenized by local scale diffusion. Mixing first deviates from Gaussian mixing, which represents the potential mixing induced by spreading before approaching it. This deviation fundamentally expresses the evolution of the interaction between spreading and local scale diffusion. We characterize it by the ratio γ of the non-Gaussian to the Gaussian mixing states. We define the Gaussian mixing state as the integrated squared concentration of the Gaussian plume that has the same longitudinal dispersion as the real plume. The non-Gaussian mixing state is the difference between the overall mixing state defined as the integrated squared concentration and the Gaussian mixing state. The main advantage of this definition is to use the full knowledge previously acquired on dispersion for characterizing mixing even when the solute concentration field is highly non Gaussian. Using high precision numerical simulations, we show that γ quickly increases, peaks and slowly decreases. γ can be derived from two scales characterizing spreading and local mixing, at least for large flux-weighted solute injection conditions into classically log-normal Gaussian correlated permeability fields. The spreading scale is directly related to the longitudinal dispersion. The local mixing scale is the largest scale over which solute concentrations can be considered locally uniform. More generally, beyond the characteristics of its maximum, γ turns out to have a highly generic scaling form. Its fast increase and slow decrease depend neither on the heterogeneity level, nor on the ratio of diffusion to advection, nor on the injection conditions. They might even not depend on the particularities of the flow fields as the same generic features also prevail for

Dentistry and HIV/AIDS related stigma.

PubMed

Elizondo, Jesus Eduardo; Treviño, Ana Cecilia; Violant, Deborah

2015-01-01

To analyze HIV/AIDS positive individual's perception and attitudes regarding dental services. One hundred and thirty-four subjects (30.0% of women and 70.0% of men) from Nuevo León, Mexico, took part in the study (2014). They filled out structured, analytical, self-administered, anonymous questionnaires. Besides the sociodemographic variables, the perception regarding public and private dental services and related professionals was evaluated, as well as the perceived stigma associated with HIV/AIDS, through a Likert-type scale. The statistical evaluation included a factorial and a non-hierarchical cluster analysis. Social inequalities were found regarding the search for public and private dental professionals and services. Most subjects reported omitting their HIV serodiagnosis and agreed that dentists must be trained and qualified to treat patients with HIV/AIDS. The factorial analysis revealed two elements: experiences of stigma and discrimination in dental appointments and feelings of concern regarding the attitudes of professionals or their teams concerning patients' HIV serodiagnosis. The cluster analysis identified three groups: users who have not experienced stigma or discrimination (85.0%); the ones who have not had those experiences, but feel somewhat concerned (12.7%); and the ones who underwent stigma and discrimination and feel concerned (2.3%). We observed a low percentage of stigma and discrimination in dental appointments; however, most HIV/AIDS patients do not reveal their serodiagnosis to dentists out of fear of being rejected. Such fact implies a workplace hazard to dental professionals, but especially to the very own health of HIV/AIDS patients, as dentists will not be able to provide them a proper clinical and pharmaceutical treatment.

Dentistry and HIV/AIDS related stigma

PubMed Central

Elizondo, Jesus Eduardo; Treviño, Ana Cecilia; Violant, Deborah

2015-01-01

OBJECTIVE To analyze HIV/AIDS positive individual’s perception and attitudes regarding dental services. METHODS One hundred and thirty-four subjects (30.0% of women and 70.0% of men) from Nuevo León, Mexico, took part in the study (2014). They filled out structured, analytical, self-administered, anonymous questionnaires. Besides the sociodemographic variables, the perception regarding public and private dental services and related professionals was evaluated, as well as the perceived stigma associated with HIV/AIDS, through a Likert-type scale. The statistical evaluation included a factorial and a non-hierarchical cluster analysis. RESULTS Social inequalities were found regarding the search for public and private dental professionals and services. Most subjects reported omitting their HIV serodiagnosis and agreed that dentists must be trained and qualified to treat patients with HIV/AIDS. The factorial analysis revealed two elements: experiences of stigma and discrimination in dental appointments and feelings of concern regarding the attitudes of professionals or their teams concerning patients’ HIV serodiagnosis. The cluster analysis identified three groups: users who have not experienced stigma or discrimination (85.0%); the ones who have not had those experiences, but feel somewhat concerned (12.7%); and the ones who underwent stigma and discrimination and feel concerned (2.3%). CONCLUSIONS We observed a low percentage of stigma and discrimination in dental appointments; however, most HIV/AIDS patients do not reveal their serodiagnosis to dentists out of fear of being rejected. Such fact implies a workplace hazard to dental professionals, but especially to the very own health of HIV/AIDS patients, as dentists will not be able to provide them a proper clinical and pharmaceutical treatment. PMID:26538100

Natural remananent magnetization acquisition through sediment mixing: theory and implications for relative paleointensity

NASA Astrophysics Data System (ADS)

Egli, Ramon; Zhao, Xiangyu

2015-04-01

We present a general theory on the acquisition of natural remanent magnetizations (NRM) in sediment under the influence of (a) magnetic torques, (b) randomizing torques (e.g. from bioturbation), and (c) torques resulting from interaction forces between remanence carriers and other particles. Dynamic equilibrium between (a) and (b) in the water column and sediment-water interface produce a detrital remanent magnetization (DRM), while much stronger randomizing forces occur in the mixed layer of sediment due to bioturbation forces. These generate a so-called mixing remanent magnetization (MRM), which is stabilized by interaction forces. During the time required to cross the mixed layer, DRM is lost and MRM is acquired at a rate that depends on bioturbation intensity. Both processes are governed by the same MRM lock-in function. The final NRM intensity is controlled mainly by a single parameter defined as the product of rotational diffusion constant and mixed layer thickness, divided by the sedimentation rate. This parameter defines three regimes: (1) slow mixing, leading to DRM preservation and insignificant MRM acquisition, (2) fast mixing with MRM acquisition and full randomization of the original DRM, and (3) intermediate mixing. Because the acquisition efficiency of DRM is expectedly larger than that of a MRM, MRM is particularly sensitive to the mixing rate in case of intermediate regimes, and generates variable NRM acquisition efficiencies. Our model explains (1) lock-in delays that can be matched with empirical reconstructions from paleomagnetic records, (2) the existence of small lock-in depths leading to DRM preservation, (3) NRM acquisition efficiencies of magnetofossil-rich sediments, and (4) relative paleointensity artifacts reported in some recent studies.

Vertical eddy diffusivity as a control parameter in the tropical Pacific

NASA Astrophysics Data System (ADS)

Martinez Avellaneda, N.; Cornuelle, B.

2011-12-01

Ocean models suffer from errors in the treatment of turbulent sub-grid-scale motions responsible for mixing and energy dissipation. Unrealistic small-scale physics in models can have large-scale consequences, such as biases in the upper ocean temperature, a symptom of poorly-simulated upwelling, currents and air-sea interactions. This is of special importance in the tropical Pacific Ocean (TP), which is home to energetic air-sea interactions that affect global climate. It has been shown in a number of studies that the simulated ENSO variability is highly dependent on the state of the ocean (e.g.: background mixing). Moreover, the magnitude of the vertical numerical diffusion is of primary importance in properly reproducing the Pacific equatorial thermocline. This work is part of a NASA-funded project to estimate the space- and time-varying ocean mixing coefficients in an eddy-permitting (1/3dgr) model of the TP to obtain an improved estimate of its time-varying circulation and its underlying dynamics. While an estimation procedure for the TP (26dgr S - 30dgr N) in underway using the MIT general circulation model, complementary adjoint-based sensitivity studies have been carried out for the starting ocean state from Forget (2010). This analysis aids the interpretation of the estimated mixing coefficients and possible error compensation. The focus of the sensitivity tests is the Equatorial Undercurrent and sub-thermocline jets (i.e., Tsuchiya Jets), which have been thought to have strong dependence on vertical diffusivity and should provide checks on the estimated mixing parameters. In order to build intuition for the vertical diffusivity adjoint results in the TP, adjoint and forward perturbed simulations were carried out for an idealized sharp thermocline in a rectangular domain.

Interactions of diffuse and focused allogenic recharge in an eogenetic karst aquifer (Florida, USA)

NASA Astrophysics Data System (ADS)

Langston, Abigail L.; Screaton, Elizabeth J.; Martin, Jonathan B.; Bailly-Comte, Vincent

2012-06-01

The karstic upper Floridan aquifer in north-central Florida (USA) is recharged by both diffuse and allogenic recharge. To understand how recharged water moves within the aquifer, water levels and specific conductivities were monitored and slug tests were conducted in wells installed in the aquifer surrounding the Santa Fe River Sink and Rise. Results indicate that diffuse recharge does not mix rapidly within the aquifer but instead flows horizontally. Stratification may be aided by the high matrix porosity of the eogenetic karst aquifer. Purging wells for sample collection perturbed conductivity for several days, reflecting mixing of the stratified water and rendering collection of representative samples difficult. Interpretive numerical simulations suggest that diffuse recharge impacts the intrusion of allogenic water from the conduit by increasing hydraulic head in the surrounding aquifer and thereby reducing influx to the aquifer from the conduit. In turn, the increase of head within the conduits affects flow paths of diffuse recharge by moving newly recharged water vertically as the water table rises and falls. This movement may result in a broad vertical zone of dissolution at the water table above the conduit system, with thinner and more focused water-table dissolution at greater distance from the conduit.

Incomplete Mixing and Reactions - A Lagrangian Approach in a Pure Shear Flow

NASA Astrophysics Data System (ADS)

Paster, A.; Aquino, T.; Bolster, D.

2014-12-01

Incomplete mixing of reactive solutes is well known to slow down reaction rates relative to what would be expected from assuming perfect mixing. As reactions progress in a system and deplete reactant concentrations, initial fluctuations in the concentrations of reactions can be amplified relative to mean background concentrations and lead to spatial segregation of reactants. As the system evolves, in the absence of sufficient mixing, this segregation will increase, leading to a persistence of incomplete mixing that fundamentally changes the effective rate at which overall reactions will progress. On the other hand, non-uniform fluid flows are known to affect mixing between interacting solutes. Thus a natural question arises: Can non-uniform flows sufficiently enhance mixing to suppress incomplete mixing effects, and if so, under what conditions? In this work we address this question by considering one of the simplest possible flows, a laminar pure shear flow, which is known to significantly enhance mixing relative to diffusion alone. To study this system we adapt a novel Lagrangian particle-based random walk method, originally designed to simulate reactions in purely diffusive systems, to the case of advection and diffusion in a shear flow. To interpret the results we develop a semi-analytical solution, by proposing a closure approximation that aims to capture the effect of incomplete mixing. The results obtained via the Lagrangian model and the semi-analytical solutions consistently highlight that if shear effects in the system are not sufficiently strong, incomplete mixing effects initially similar to purely diffusive systems will occur, slowing down the overall reaction rate. Then, at some later time, dependent on the strength of the shear, the system will return to behaving as if it were well-mixed, but represented by a reduced effective reaction rate. If shear effects are sufficiently strong, the incomplete mixing regime never emerges and the system can behave

Incomplete Mixing and Reactions - A Lagrangian Approach in a Pure Shear Flow

NASA Astrophysics Data System (ADS)

Paster, Amir; Bolster, Diogo; Aquino, Tomas

2015-04-01

Incomplete mixing of reactive solutes is well known to slow down reaction rates relative to what would be expected from assuming perfect mixing. As reactions progress in a system and deplete reactant concentrations, initial fluctuations in the concentrations of reactions can be amplified relative to mean background concentrations and lead to spatial segregation of reactants. As the system evolves, in the absence of sufficient mixing, this segregation will increase, leading to a persistence of incomplete mixing that fundamentally changes the effective rate at which overall reactions will progress. On the other hand, nonuniform fluid flows are known to affect mixing between interacting solutes. Thus a natural question arises: Can non-uniform flows sufficiently enhance mixing to suppress incomplete mixing effects, and if so, under what conditions? In this work we address this question by considering one of the simplest possible flows, a laminar pure shear flow, which is known to significantly enhance mixing relative to diffusion alone. To study this system we adapt a novel Lagrangian particle-based random walk method, originally designed to simulate reactions in purely diffusive systems, to the case of advection and diffusion in a shear flow. To interpret the results we develop a semi-analytical solution, by proposing a closure approximation that aims to capture the effect of incomplete mixing. The results obtained via the Lagrangian model and the semi-analytical solutions consistently highlight that if shear effects in the system are not sufficiently strong, incomplete mixing effects initially similar to purely diffusive systems will occur, slowing down the overall reaction rate. Then, at some later time, dependent on the strength of the shear, the system will return to behaving as if it were well-mixed, but represented by a reduced effective reaction rate. If shear effects are sufficiently strong, the incomplete mixing regime never emerges and the system can behave

The parallel-antiparallel signal difference in double-wave-vector diffusion-weighted MR at short mixing times: A phase evolution perspective

NASA Astrophysics Data System (ADS)

Finsterbusch, Jürgen

2011-01-01

Experiments with two diffusion weightings applied in direct succession in a single acquisition, so-called double- or two-wave-vector diffusion-weighting (DWV) experiments at short mixing times, have been shown to be a promising tool to estimate cell or compartment sizes, e.g. in living tissue. The basic theory for such experiments predicts that the signal decays for parallel and antiparallel wave vector orientations differ by a factor of three for small wave vectors. This seems to be surprising because in standard, single-wave-vector experiments the polarity of the diffusion weighting has no influence on the signal attenuation. Thus, the question how this difference can be understood more pictorially is often raised. In this rather educational manuscript, the phase evolution during a DWV experiment for simple geometries, e.g. diffusion between parallel, impermeable planes oriented perpendicular to the wave vectors, is considered step-by-step and demonstrates how the signal difference develops. Considering the populations of the phase distributions obtained, the factor of three between the signal decays which is predicted by the theory can be reproduced. Furthermore, the intermediate signal decay for orthogonal wave vector orientations can be derived when investigating diffusion in a box. Thus, the presented “phase gymnastics” approach may help to understand the signal modulation observed in DWV experiments at short mixing times.

Stellar models with microscopic diffusion and rotational mixing. 2: Application to open clusters

NASA Technical Reports Server (NTRS)

Chaboyer, B.; Demarque, P.; Pinsonneault, M. H.

1995-01-01

Stellar models with masses ranging from 05.5 to 1.3 solar mass were constructed for comparison with young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of overshoot at the base of the surface convection zone, and the exact metallicity of the models. Even when this is taken into account, the Li observations are a severe constraint for the models and rule out standard models and pure diffusion models. Stellar models which include diffusion and rotational mixing in the radiative regions of stars are able to simultaneously match the Li abundances observed in the Pleiades, the UMa Group, The Hyades, Praesepe, NGC 752, and M67. They also match the observed rotation periods in the Hyades. However, these models are unable to simultaneously explain the presence of the rapidly rotating late G and K stars in the Pleiades and the absence of rapidly rotating late F and early G stars.

HIV/AIDS and time allocation in rural Malawi

PubMed Central

Bignami-Van Assche, Simona; Van Assche, Ari; Anglewicz, Philip; Fleming, Peter; van de Ruit, Catherine

2012-01-01

AIDS-related morbidity and mortality are expected to have a large economic impact in rural Malawi, because they reduce the time that adults can spend on production for subsistence and on income-generating activities. However, households may compensate for production losses by reallocating tasks among household members. The data demands for measuring these effects are high, limiting the amount of empirical evidence. In this paper, we utilize a unique combination of qualitative and quantitative data, including biomarkers for HIV, collected by the 2004 Malawi Diffusion and Ideational Change Project, to analyze the association between AIDS-related morbidity and mortality, and time allocation decisions in rural Malawian households. We find that AIDS-related morbidity and mortality have important economic effects on women’s time, whereas men’s time is unresponsive to the same shocks. Most notably, AIDS is shown to induce diversification of income sources, with women (but not men) reallocating their time, generally from work-intensive (typically farming and heavy chores) to cash-generating tasks (such as casual labor). PMID:22639544

Vortex-scalar element calculations of a diffusion flame stabilized on a plane mixing layer

NASA Technical Reports Server (NTRS)

Ghoniem, Ahmed F.; Givi, Peyman

1987-01-01

The vortex-scalar element method, a scheme which utilizes vortex elements to discretize the region of high vorticity and scalar elements to represent species or temperature fields, is utilized in the numerical simulations of a two-dimensional reacting mixing layer. Computations are performed for a diffusion flame at high Reynolds and Peclet numbers without resorting to turbulence models. In the nonreacting flow, the mean and fluctuation profiles of a conserved scalar show good agreement with experimental measurements. Results for the reacting flow indicate that for temperature independent kinetics, the chemical reaction begins immediately downstream of the splitter plate where mixing starts. Results for the reacting flow with Arrhenius kinetics show an ignition delay, which depends on reactant temperature, before significant chemical reaction occurs. Harmonic forcing changes the structure of the layer, and concomitantly the rates of mixing and reaction, in accordance with experimental results. Strong stretch within the braids in the nonequilibrium kinetics case causes local flame quenching due to the temperature drop associated with the large convective fluxes.

Differentiating Tumor Progression from Pseudoprogression in Patients with Glioblastomas Using Diffusion Tensor Imaging and Dynamic Susceptibility Contrast MRI.

PubMed

Wang, S; Martinez-Lage, M; Sakai, Y; Chawla, S; Kim, S G; Alonso-Basanta, M; Lustig, R A; Brem, S; Mohan, S; Wolf, R L; Desai, A; Poptani, H

2016-01-01

Early assessment of treatment response is critical in patients with glioblastomas. A combination of DTI and DSC perfusion imaging parameters was evaluated to distinguish glioblastomas with true progression from mixed response and pseudoprogression. Forty-one patients with glioblastomas exhibiting enhancing lesions within 6 months after completion of chemoradiation therapy were retrospectively studied. All patients underwent surgery after MR imaging and were histologically classified as having true progression (>75% tumor), mixed response (25%-75% tumor), or pseudoprogression (<25% tumor). Mean diffusivity, fractional anisotropy, linear anisotropy coefficient, planar anisotropy coefficient, spheric anisotropy coefficient, and maximum relative cerebral blood volume values were measured from the enhancing tissue. A multivariate logistic regression analysis was used to determine the best model for classification of true progression from mixed response or pseudoprogression. Significantly elevated maximum relative cerebral blood volume, fractional anisotropy, linear anisotropy coefficient, and planar anisotropy coefficient and decreased spheric anisotropy coefficient were observed in true progression compared with pseudoprogression (P < .05). There were also significant differences in maximum relative cerebral blood volume, fractional anisotropy, planar anisotropy coefficient, and spheric anisotropy coefficient measurements between mixed response and true progression groups. The best model to distinguish true progression from non-true progression (pseudoprogression and mixed) consisted of fractional anisotropy, linear anisotropy coefficient, and maximum relative cerebral blood volume, resulting in an area under the curve of 0.905. This model also differentiated true progression from mixed response with an area under the curve of 0.901. A combination of fractional anisotropy and maximum relative cerebral blood volume differentiated pseudoprogression from

Macromolecular crowding effect upon in vitro enzyme kinetics: mixed activation-diffusion control of the oxidation of NADH by pyruvate catalyzed by lactate dehydrogenase.

PubMed

Balcells, Cristina; Pastor, Isabel; Vilaseca, Eudald; Madurga, Sergio; Cascante, Marta; Mas, Francesc

2014-04-17

Enzyme kinetics studies have been usually designed as dilute solution experiments, which differ substantially from in vivo conditions. However, cell cytosol is crowded with a high concentration of molecules having different shapes and sizes. The consequences of such crowding in enzymatic reactions remain unclear. The aim of the present study is to understand the effect of macromolecular crowding produced by dextran of different sizes and at diverse concentrations in the well-known reaction of oxidation of NADH by pyruvate catalyzed by L-lactate dehydrogenase (LDH). Our results indicate that the reaction rate is determined by both the occupied volume and the relative size of dextran obstacles with respect to the enzyme present in the reaction. Moreover, we analyzed the influence of macromolecular crowding on the Michaelis-Menten constants, vmax and Km. The obtained results show that only high concentrations and large sizes of dextran reduce both constants suggesting a mixed activation-diffusion control of this enzymatic reaction due to the dextran crowding action. From our knowledge, this is the first experimental study that depicts mixed activation-diffusion control in an enzymatic reaction due to the effect of crowding.

Diffuse Scattering as an Aid to the Understanding of Polymorphism in Pharmaceuticals

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

Welberry, T.R.; Chan, E.J.; Goossens, D.J.

Polymorphism occurs when the same molecular compound can crystallize in more than one distinct crystal structure. Its study is a field of great interest and activity. This is largely driven by its importance in the pharmaceutical industry, but polymorphism is also an issue in the pigments, dyes, and explosives industries. The polymorph formed by a compound generally exerts a strong influence on its solid-state properties. The polymorphic form of a drug molecule may affect the ease of manufacture and processing, shelf life, and most significantly the rate of uptake of the molecule by the human body. They can even varymore » in toxicity; one polymorph may be safe, while a second may be toxic. In this review of recently published work, we show how diffuse scattering experiments coupled with Monte Carlo (MC) computer modeling can aid in the understanding of polymorphism. Examples of the two common pharmaceuticals, benzocaine and aspirin, both of which are bimorphic, at ambient temperatures, are discussed.« less

Diffuse Scattering as an Aid to the Understanding of Polymorphism in Pharmaceuticals

NASA Astrophysics Data System (ADS)

Welberry, T. R.; Chan, E. J.; Goossens, D. J.; Heerdegen, A. P.

2012-05-01

Polymorphism occurs when the same molecular compound can crystallize in more than one distinct crystal structure. Its study is a field of great interest and activity. This is largely driven by its importance in the pharmaceutical industry, but polymorphism is also an issue in the pigments, dyes, and explosives industries. The polymorph formed by a compound generally exerts a strong influence on its solid-state properties. The polymorphic form of a drug molecule may affect the ease of manufacture and processing, shelf life, and most significantly the rate of uptake of the molecule by the human body. They can even vary in toxicity; one polymorph may be safe, while a second may be toxic. In this review of recently published work, we show how diffuse scattering experiments coupled with Monte Carlo (MC) computer modeling can aid in the understanding of polymorphism. Examples of the two common pharmaceuticals, benzocaine and aspirin, both of which are bimorphic, at ambient temperatures, are discussed.

SMALL-SCALE ANISOTROPIES OF COSMIC RAYS FROM RELATIVE DIFFUSION

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

Ahlers, Markus; Mertsch, Philipp

2015-12-10

The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small-scale structure can naturally arise from cosmic ray scattering in local turbulent magnetic fields that distort a global dipole anisotropy set by diffusion. We study this effect in terms of the power spectrum of cosmic ray arrival directions and show that the strength of small-scale anisotropies is related to properties of relative diffusion. We provide a formalism for how these power spectra can be inferred from simulations and motivate a simple analytic extension of the ensemble-averaged diffusion equation that canmore » account for the effect.« less

Numerical analysis of mixing enhancement for micro-electroosmotic flow

NASA Astrophysics Data System (ADS)

Tang, G. H.; He, Y. L.; Tao, W. Q.

2010-05-01

Micro-electroosmotic flow is usually slow with negligible inertial effects and diffusion-based mixing can be problematic. To gain an improved understanding of electroosmotic mixing in microchannels, a numerical study has been carried out for channels patterned with wall blocks, and channels patterned with heterogeneous surfaces. The lattice Boltzmann method has been employed to obtain the external electric field, electric potential distribution in the electrolyte, the flow field, and the species concentration distribution within the same framework. The simulation results show that wall blocks and heterogeneous surfaces can significantly disturb the streamlines by fluid folding and stretching leading to apparently substantial improvements in mixing. However, the results show that the introduction of such features can substantially reduce the mass flow rate and thus effectively prolongs the available mixing time when the flow passes through the channel. This is a non-negligible factor on the effectiveness of the observed improvements in mixing efficiency. Compared with the heterogeneous surface distribution, the wall block cases can achieve more effective enhancement in the same mixing time. In addition, the field synergy theory is extended to analyze the mixing enhancement in electroosmotic flow. The distribution of the local synergy angle in the channel aids to evaluate the effectiveness of enhancement method.

Measuring HIV/AIDS-Related Stigma across South Africa: A Versatile and Multidimensional Scale

ERIC Educational Resources Information Center

Smith, Edward A.; Miller, Jacqueline A.; Newsome, Valerie; Sofolahan, Yewande A.; Airhihenbuwa, Collins O.

2014-01-01

Reducing HIV/AIDS-related stigma is critical in the fight against HIV/AIDS. Although national campaigns and prevention programs have been implemented across South Africa to address this critical concern, assessing the impact of these initiatives is difficult as it requires that measurement of HIV/AIDS-related stigma is uniform and comparable…

Validity and Reliability of Persian Version of HIV/AIDS Related Stigma Scale for People Living With HIV/AIDS in Iran.

PubMed

Pourmarzi, Davoud; Khoramirad, Ashraf; Ahmari Tehran, Hoda; Abedini, Zahra

2015-11-01

To assess the perceived HIV/AIDS related stigma a comprehensive and well developed stigma instrument is necessary. This study aimed to assess validity and reliability of the Persian version of HIV/AIDS related stigma scale which was developed by Kang et al for people living with HIV/AIDS in Iran. Thescale was forward translatedby two bilingual academic members then both translations were discussed by expert team. Back-translation was done by two other bilingual translators then we carried out discussion with both of them. To evaluate understandability the scale was administered to 10 Persons Living with HIV/AIDS (PLWHA). Final Persian version was administered to 80 PLWHA in Qom, Iran in 2014. Test-retest reliability was assessed in a sample of 20 PLWHA after a week by intra-class correlation coefficient (ICC). Cronbach's alpha coefficient for overall scale was 0.85. Also Cronbach's alpha coefficients for the five subscales were as follows: social rejection (9 items, α = 0.84), negative self-worth (4 items, α = 0.70), perceived interpersonal insecurity (2 items, α = 0.57), financial insecurity (3 items, α = 0.70), discretionary disclosure (2 items, α = 0.83). Test-retest reliability was also approved with ICC = 0.78. Correlation between items and their hypothesized subscale is greater than 0.5. Correlation between an item and its own subscale was significantly higher than its correlation with other subscales. This study demonstrate that the Persian version of HIV/AIDS related stigma scale is valid and reliable to assess HIV/AIDS related stigma perceived by people living whit HIV/AIDS in Iran.

Exploring Ivorian Perspectives on the Effectiveness of the Current Ivorian Science Curriculum in Addressing Issues Related to HIV/AIDS

ERIC Educational Resources Information Center

Ado, Gustave Firmin

2014-01-01

School-based HIV/AIDS science education has the potential to impact students when integrated into the science curriculum. However, this mixed method study shows that school-based HIV/AIDS science education is often not infused into career subjects such as science education but integrated into civics education and taught by teachers who lack the…

The AIDS-related activities of religious leaders in Malawi

PubMed Central

TRINTAPOLI, J.

2010-01-01

The AIDS-related activities of religious leaders in Africa extend far beyond preaching about sexual mortality. This study aims to quantify the involvement of religious leaders in the fight against AIDS and to identify key predictors of the types of prevention strategies they promote. Using data from a random sample of Christian and Muslim leaders in Malawi, I use logistic regression to predict six types of AIDS activities, which correspond to three distinct types: formal messages (i.e., preaching), pragmatic interventions (monitoring the sexual behaviour of members and advising divorce to avoid infection), and the promotion of biomedical prevention strategies (promoting condom use and testing for HIV). Preaching about AIDS is the most common prevention activity, and promoting condom use is the least; sizable proportions of clergy promote testing and engage in pragmatic interventions. Denominational patterns in the type of engagement are weak and inconsistent. However, inquiries into the motivation for leaders' activities show that discussions with members about AIDS is the most consistent predictor, suggesting that religious leaders' engagement with HIV prevention is primarily a demand-driven phenomenon. PMID:20552476

Validity and Reliability of Persian Version of HIV/AIDS Related Stigma Scale for People Living With HIV/AIDS in Iran

PubMed Central

Pourmarzi, Davoud; Khoramirad, Ashraf; Ahmari Tehran, Hoda; Abedini, Zahra

2015-01-01

Objective: To assess the perceived HIV/AIDS related stigma a comprehensive and well developed stigma instrument is necessary. This study aimed to assess validity and reliability of the Persian version of HIV/AIDS related stigma scale which was developed by Kang et al for people living with HIV/AIDS in Iran. Materials and methods: Thescale was forward translatedby two bilingual academic members then both translations were discussed by expert team. Back-translation was done by two other bilingual translators then we carried out discussion with both of them. To evaluate understandability the scale was administered to 10 Persons Living with HIV/AIDS (PLWHA). Final Persian version was administered to 80 PLWHA in Qom, Iran in 2014. Test–retest reliability was assessed in a sample of 20 PLWHA after a week by intra-class correlation coefficient (ICC). Results: Cronbach’s alpha coefficient for overall scale was 0.85. Also Cronbach’s alpha coefficients for the five subscales were as follows: social rejection (9 items, α = 0.84), negative self-worth (4 items, α = 0.70), perceived interpersonal insecurity (2 items, α = 0.57), financial insecurity (3 items, α = 0.70), discretionary disclosure (2 items, α = 0.83). Test–retest reliability was also approved with ICC = 0.78. Correlation between items and their hypothesized subscale is greater than 0.5. Correlation between an item and its own subscale was significantly higher than its correlation with other subscales. Conclusion: This study demonstrate that the Persian version of HIV/AIDS related stigma scale is valid and reliable to assess HIV/AIDS related stigma perceived by people living whit HIV/AIDS in Iran. PMID:27047562

First Aid for Sports-Related Dental Injuries.

ERIC Educational Resources Information Center

Castaldi, C. R.

1987-01-01

Sports-related dental injuries are common but first aid is usually performed by non-dental personnel. This article describes basic procedures to be followed in order to diagnose the type and severity of the injury and to determine whether emergency treatment is required. Prevention of dental injuries is addressed. (Author/MT)

Accounts from the field: a public relations perspective on global AIDS/HIV.

PubMed

Bardhan, Nilanjana R

2002-01-01

This study is a theoretical as well as empirical exploration of the power and cultural differentials that mark and construct various intersecting discourses, specifically media discourse, on global AIDS/HIV. It applies the language and concepts of public relations to understand how the press coverage of the pandemic is associated with the variables that impact the newsmaking process as well as the public and policy implications of macro news frames generated over time. Theoretical work in the areas of agenda setting and news framing also instruct the conceptual framework of this analysis. Narrative analysis is used as a methodology to qualitatively analyze three pools of accounts-from people either living with AIDS/HIV, involved in AIDS/HIV work, or discursively engaged in the media construction of the pandemic; from transnational wire service journalists who cover the issue at global and regional levels; and policy shapers and communicators who are active at the global level. These three communities of respondents represent important stakeholders in the AIDS/HIV issue. The findings are analyzed from a public relations standpoint. Perhaps the most important finding of this study is that the public relations approaches used to address AIDS/HIV related issues need to be grounded in context-specific research and communicative practices that bring out the lived realities of AIDS/HIV at grassroots levels. The findings also posit that those situated at critical junctions between various stakeholders need to cultivate a finely balanced understanding of the etic and emic intersections and subjectivities of global/local AIDS/HIV.

Patient, surgeon, and healthcare purchaser views on the use of decision and communication aids in orthopaedic surgery: a mixed methods study.

PubMed

Bozic, Kevin J; Chenok, Kate Eresian; Schindel, Jennifer; Chan, Vanessa; Huddleston, James I; Braddock, Clarence; Belkora, Jeffrey

2014-08-31

Despite evidence that decision and communication aids are effective for enhancing the quality of preference-sensitive decisions, their adoption in the field of orthopaedic surgery has been limited. The purpose of this mixed-methods study was to evaluate the perceived value of decision and communication aids among different healthcare stakeholders. Patients with hip or knee arthritis, orthopaedic surgeons who perform hip and knee replacement procedures, and a group of large, self-insured employers (healthcare purchasers) were surveyed regarding their views on the value of decision and communication aids in orthopaedics. Patients with hip or knee arthritis who participated in a randomized controlled trial involving decision and communication aids were asked to complete an online survey about what was most and least beneficial about each of the tools they used, the ideal mode of administration of these tools and services, and their interest in receiving comparable materials and services in the future. A subset of these patients were invited to participate in a telephone interview, where there were asked to rank and attribute a monetary value to the interventions. These interviews were analyzed using a qualitative and mixed methods analysis software. Members of the American Hip and Knee Surgeons (AAHKS) were surveyed on their perceptions and usage of decision and communication aids in orthopaedic practice. Healthcare purchasers were interviewed about their perspectives on patient-oriented decision support. All stakeholders saw value in decision and communication aids, with the major barrier to implementation being cost. Both patients and surgeons would be willing to bear at least part of the cost of implementing these tools, while employers felt health plans should be responsible for shouldering the costs. Decision and communication aids can be effective tools for incorporating patients preferences and values into preference-sensitive decisions in orthopaedics. Future

Thyroid hormone levels in the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex.

PubMed Central

Tang, W W; Kaptein, E M

1989-01-01

Hypothalamic-pituitary dysfunction and thyroid gland cytomegalovirus inclusions have been described in patients with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC). We evaluated 80 patients with AIDS or ARC for the frequency of hypothalamic-pituitary or thyroid gland failure and altered serum thyroid hormone levels due to nonthyroidal disorders. One patient had subclinical hypothyroidism. Of these patients, 60% had low free triiodothyronine (T3) index values and 4% had low free thyroxine (T4) indexes; none of the latter had hypothalamic-pituitary or thyroid gland failure, since all serum cortisol values were greater than or equal to 552 nmol per liter (greater than or equal to 20 micrograms per dl) and all thyrotropin levels were less than or equal to 3 mU per liter (less than or equal to 3 microU per ml), respectively. Those who died had lower total T4 and T3, free T3 index, and albumin levels than those discharged from hospital. Serum total T4 and T3 levels correlated with albumin levels and total T3 with serum sodium levels. Serum total T3 levels best predicted the outcome of the hospital stay (accuracy = 82%). Thus, abnormal serum thyroid hormone levels in AIDS or ARC patients are most frequently due to nonthyroidal disorders, but hypothalamic-pituitary or thyroid gland failure may occur. PMID:2618039

Determination of sedimentation, diffusion, and mixing rates in coastal sediments of the eastern Red Sea via natural and anthropogenic fallout radionuclides.

PubMed

Al-Mur, Bandar A; Quicksall, Andrew N; Kaste, James M

2017-09-15

The Red Sea is a unique ecosystem with high biodiversity in one of the warmest regions of the world. In the last five decades, Red Sea coastal development has rapidly increased. Sediments from continental margins are delivered to depths by advection and diffusion-like processes which are difficult to quantify yet provide invaluable data to researchers. Beryllium-7, lead-210 and ceseium-137 were analyzed from sediment cores from the near-coast Red Sea near Jeddah, Saudi Arabia. The results of this work are the first estimates of diffusion, mixing, and sedimentation rates of the Red Sea coastal sediments. Maximum chemical diffusion and particle mixing rates range from 69.1 to 380cm -2 y -1 and 2.54 to 6.80cm -2 y -1 , respectively. Sedimentation rate is constrained to approximately 0.6cm/yr via multiple methods. These data provide baselines for tracking changes in various environmental problems including erosion, marine benthic ecosystem silting, and particle-bound contaminant delivery to the seafloor. Copyright © 2017. Published by Elsevier Ltd.

AIDS-Related Lymphoma Treatment (PDQ®)—Health Professional Version

Cancer.gov

AIDS-related lymphoma treatment may include chemotherapy, radiation therapy, high-dose chemotherapy with stem cell transplant, and/or targeted therapy. Get detailed information about the diagnosis and treatment of newly diagnosed and recurrent HIV-related lymphoma in this summary for clinicians.

Securitizing HIV/AIDS: a game changer in state-societal relations in China?

PubMed

Lo, Catherine Yuk-Ping

2018-05-16

China has experienced unprecedented economic growth since the 1980s. Despite this impressive economic development, this growth exists side by side with the human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) and severe acute respiratory syndrome (SARS) crises and the persisting deficiencies in public health provision in China. Acknowledging the prevailing health problems, the Chinese government has encouraged the development of health non-governmental organizations (NGOs) to respond to the health challenges and address the gaps in public health provision of the government. HIV/AIDS-focused NGOs have been perceived as the most outstanding civil society group developed in China. Considering the low priority of health policies since the economic reform, the limitation of the "third sector" activity permitted in authoritarian China, together with the political sensitivity of the HIV/AIDS problem in the country, this article aims to explain the proliferation of HIV/AIDS-focused NGOs in China with the usage of the securitization framework in the field of international relations (IR). The research that underpins this article is based on a desk-based literature review as well as in-depth field interviews with individuals working in HIV/AIDS-focused NGOs in China. Face-to-face interviews for this research were conducted between January and May in 2011, and between December 2016 and January 2017, in China. Discourse analysis was in particular employed in the study of the security-threat framing process (securitization) of HIV/AIDS in China. This article argues that the proliferation of HIV/AIDS-related NGOs in China is largely attributed to the normative and technical effects of HIV/AIDS securitization ushered in by the United Nations Security Council (UNSC) and supported by the Global Fund to Fight AIDS, Tuberculosis, and Malaria (hereinafter Global Fund) observed in China. Despite depicting a positive scenario, the development of HIV/AIDS

Diffusion-based recommendation with trust relations on tripartite graphs

NASA Astrophysics Data System (ADS)

Wang, Ximeng; Liu, Yun; Zhang, Guangquan; Xiong, Fei; Lu, Jie

2017-08-01

The diffusion-based recommendation approach is a vital branch in recommender systems, which successfully applies physical dynamics to make recommendations for users on bipartite or tripartite graphs. Trust links indicate users’ social relations and can provide the benefit of reducing data sparsity. However, traditional diffusion-based algorithms only consider rating links when making recommendations. In this paper, the complementarity of users’ implicit and explicit trust is exploited, and a novel resource-allocation strategy is proposed, which integrates these two kinds of trust relations on tripartite graphs. Through empirical studies on three benchmark datasets, our proposed method obtains better performance than most of the benchmark algorithms in terms of accuracy, diversity and novelty. According to the experimental results, our method is an effective and reasonable way to integrate additional features into the diffusion-based recommendation approach.

A Basin-Wide Examination of the Arctic Ocean's Double-Diffusive Staircase

NASA Astrophysics Data System (ADS)

Shibley, N.; Timmermans, M. L.; Carpenter, J. R.; Toole, J. M.

2016-02-01

The Arctic Ocean thermohaline stratification frequently exhibits a staircase structure above the Atlantic Water Layer consisting of multiple mixed layers of order 1-m in height separated by sharp interfaces. This double-diffusive staircase structure is characterized across the entire Arctic Ocean through a detailed analysis of Ice-Tethered Profiler measurements acquired between 2004 and 2013. Staircase properties (mixed layer thicknesses and temperature-salinity jumps across interfaces) are examined in relation to a bulk vertical density ratio for 50-m spanning the staircase stratification. It is shown that the Lomonosov Ridge serves as an approximate boundary between regions of low density ratio (on the Eurasian side) and higher density ratio (on the Canadian side). We find that the diffusive staircase in the Eurasian Basin is characterized by fewer, thinner mixed layers than that in the Canadian Basin, although the margins of all basins are characterized by relatively thin staircase mixed layers. Using a double-diffusive 4/3 flux law parameterization, the distribution of vertical heat fluxes through the staircase is estimated across the Arctic; it is found that heat fluxes in the Eurasian Basin [O(1) W/m^2] are generally an order of magnitude larger than those in the Canadian Basin [O(0.1) W/m^2].

Ibrutinib, Rituximab, Etoposide, Prednisone, Vincristine Sulfate, Cyclophosphamide, and Doxorubicin Hydrochloride in Treating Patients With HIV-Positive Stage II-IV Diffuse Large B-Cell Lymphomas

ClinicalTrials.gov

2018-06-11

AIDS-Related Lymphoma; Ann Arbor Stage II Diffuse Large B-Cell Lymphoma; Ann Arbor Stage III Diffuse Large B-Cell Lymphoma; Ann Arbor Stage IV Diffuse Large B-Cell Lymphoma; CD20 Negative; CD20 Positive; Human Immunodeficiency Virus Positive

AIDS with acute cerebral infarct: a case report.

PubMed

Wu, Lin-Hui; Chen, Wei-Hung; Lien, Li-Ming; Huang, Chien-Hsien; Chiu, Hou-Chang

2005-06-01

A 38 year-old male presented with an acute onset of left hemiplegia. Brain magnetic resonance imaging (MRI) revealed a bright lesion by diffusion-weighted imaging with low apparent diffusion coefficient value in the right subcortical region, a finding compatible with an acute cerebral infarct. An old infarct was also noted in the same imaging. Both enzyme-linked immunosorbent assay and Western blot method were positive for human immunodeficiency virus infection. The white blood cell count was 2930 cells / mm3, and the subpopulation study for lymphocyte revealed a decreased cluster of differentiation 4+ count of 149 cells/mm3. Studies for prothrombotic states showed decreased protein S and increased anticardiolipin antibodies. We concluded that this was a case of acquired immunodeficiency syndrome (AIDS) with acute and old cerebral infarcts. This patient might be the first reported case in Taiwan. AIDS might be related with stroke in young patients, a condition probably under-recognized in Taiwan.

AIDS-Related Lymphoma Treatment (PDQ®)—Health Professional Version

Cancer.gov

AIDS-related lymphoma presents and is treated differently compared to lymphoma in non-HIV patients. Treatments include chemotherapy, radiation therapy, high-dose chemotherapy with stem cell transplant, and targeted therapy. Get detailed information about HIV-related lymphoma in this summary for clinicians.

CO Diffusion into Amorphous H2O Ices

NASA Astrophysics Data System (ADS)

Lauck, Trish; Karssemeijer, Leendertjan; Shulenberger, Katherine; Rajappan, Mahesh; Öberg, Karin I.; Cuppen, Herma M.

2015-03-01

The mobility of atoms, molecules, and radicals in icy grain mantles regulates ice restructuring, desorption, and chemistry in astrophysical environments. Interstellar ices are dominated by H2O, and diffusion on external and internal (pore) surfaces of H2O-rich ices is therefore a key process to constrain. This study aims to quantify the diffusion kinetics and barrier of the abundant ice constituent CO into H2O-dominated ices at low temperatures (15-23 K), by measuring the mixing rate of initially layered H2O(:CO2)/CO ices. The mixed fraction of CO as a function of time is determined by monitoring the shape of the infrared CO stretching band. Mixing is observed at all investigated temperatures on minute timescales and can be ascribed to CO diffusion in H2O ice pores. The diffusion coefficient and final mixed fraction depend on ice temperature, porosity, thickness, and composition. The experiments are analyzed by applying Fick’s diffusion equation under the assumption that mixing is due to CO diffusion into an immobile H2O ice. The extracted energy barrier for CO diffusion into amorphous H2O ice is ˜160 K. This is effectively a surface diffusion barrier. The derived barrier is low compared to current surface diffusion barriers in use in astrochemical models. Its adoption may significantly change the expected timescales for different ice processes in interstellar environments.

[Survival time of HIV/AIDS cases and related factors in Beijing, 1995-2015].

PubMed

Li, Y; Wang, J; He, S F; Chen, J; Lu, H Y

2017-11-10

Objective: To analyze the survival time of HIV/AIDS cases and related factors in Beijing from 1995 to 2015. Methods: A retrospective cohort study was conducted to analyze the data of 12 874 HIV/AIDS cases. The data were collected from Chinese HIV/AIDS Comprehensive Information Management System. Life table method was applied to calculate the survival proportion, and Cox proportion hazard regression model were used to identify the factors related with survival time. Results: Among 12 874 HIV/AIDS cases, 303 (2.4%) died of AIDS related diseases; 9 346 (72.6%) received antiretroviral therapy. The average survival time was 226.5 months (95 %CI : 223.0-230.1), and the survival rates of 1, 5, 10, and 15 years were 98.2%, 96.4%, 93.2%, and 91.9% respectively. Multivariate Cox proportion hazard regression model showed that AIDS phase ( HR =1.439, 95 %CI : 1.041-1.989), heterosexual transmission ( HR =1.646, 95 %CI : 1.184-2.289), being married ( HR =2.186, 95 %CI : 1.510-3.164); older age (≥60 years) at diagnosis ( HR =6.608, 95 %CI : 3.546-12.316); lower CD(4)(+)T cell counts at diagnosis (<350 cells/μl) ( HR =8.711, 95 %CI : 5.757-13.181); receiving no antiretroviral therapy (ART) ( HR =18.223, 95 %CI : 13.317-24.937) were the high risk factors influencing the survival of AIDS patients compared with HIV phase, homosexual transmission, being unmarried, younger age (≤30 years), higher CD(4)(+)T cell count (≥350 cell/μl) and receiving ART. Conclusion: The average survival time of HIV/AIDS cases was 226.5 months after diagnoses. Receiving ART, higher CD(4)(+)T cell counts at the first test, HIV phase, younger age, being unmarried and the homosexual transmission were related to the longer survival time of HIV/AIDS cases. Receiving no ART, the lower CD(4)(+)T cell counts at the first test, AIDS phase, older age, being married and heterosexual transmission indicated higher risk of death due to AIDS.

Turbulent vertical diffusivity in the sub-tropical stratosphere

NASA Astrophysics Data System (ADS)

Pisso, I.; Legras, B.

2008-02-01

Vertical (cross-isentropic) mixing is produced by small-scale turbulent processes which are still poorly understood and paramaterized in numerical models. In this work we provide estimates of local equivalent diffusion in the lower stratosphere by comparing balloon borne high-resolution measurements of chemical tracers with reconstructed mixing ratio from large ensembles of random Lagrangian backward trajectories using European Centre for Medium-range Weather Forecasts analysed winds and a chemistry-transport model (REPROBUS). We focus on a case study in subtropical latitudes using data from HIBISCUS campaign. An upper bound on the vertical diffusivity is found in this case study to be of the order of 0.5 m2 s-1 in the subtropical region, which is larger than the estimates at higher latitudes. The relation between diffusion and dispersion is studied by estimating Lyapunov exponents and studying their variation according to the presence of active dynamical structures.

Addressing Ebola-related stigma: lessons learned from HIV/AIDS.

PubMed

Davtyan, Mariam; Brown, Brandon; Folayan, Morenike Oluwatoyin

2014-01-01

HIV/AIDS and Ebola Virus Disease (EVD) are contemporary epidemics associated with significant social stigma in which communities affected suffer from social rejection, violence, and diminished quality of life. To compare and contrast stigma related to HIV/AIDS and EVD, and strategically think how lessons learned from HIV stigma can be applied to the current EVD epidemic. To identify relevant articles about HIV/AIDS and EVD-related stigma, we conducted an extensive literature review using multiple search engines. PubMed was used to search for relevant peer-reviewed journal articles and Google for online sources. We also consulted the websites of the World Health Organization (WHO), Centers for Disease Control and Prevention (CDC), and the National Institutes of Health to retrieve up-to-date information about EVD and HIV/AIDS. Many stigmatizing attitudes and behaviors directed towards those with EVD are strikingly similar to those with HIV/AIDS but there are significant differences worthy of discussion. Both diseases are life-threatening and there is no medical cure. Additionally misinformation about affected groups and modes of transmission runs rampant. Unlike in persons with EVD, historically criminalized and marginalized populations carry a disproportionately higher risk for HIV infection. Moreover, mortality due to EVD occurs within a shorter time span as compared to HIV/AIDS. Stigma disrupts quality of life, whether it is associated with HIV infection or EVD. When addressing EVD, we must think beyond the immediate clinical therapeutic response, to possible HIV implications of serum treatment. There are emerging social concerns of stigma associated with EVD infection and double stigma associated with EVD and HIV infection. Drawing upon lessons learned from HIV, we must work to empower and mobilize prominent members of the community, those who recovered from the disease, and organizations working at the grassroots level to disseminate clear and accurate

A coupling strategy for nonlocal and local diffusion models with mixed volume constraints and boundary conditions

DOE PAGES

D'Elia, Marta; Perego, Mauro; Bochev, Pavel B.; ...

2015-12-21

We develop and analyze an optimization-based method for the coupling of nonlocal and local diffusion problems with mixed volume constraints and boundary conditions. The approach formulates the coupling as a control problem where the states are the solutions of the nonlocal and local equations, the objective is to minimize their mismatch on the overlap of the nonlocal and local domains, and the controls are virtual volume constraints and boundary conditions. When some assumptions on the kernel functions hold, we prove that the resulting optimization problem is well-posed and discuss its implementation using Sandia’s agile software components toolkit. As a result,more » the latter provides the groundwork for the development of engineering analysis tools, while numerical results for nonlocal diffusion in three-dimensions illustrate key properties of the optimization-based coupling method.« less

Aids-Related Cancers in Africa

NASA Astrophysics Data System (ADS)

Mbulaiteye, Sam M.

2014-07-01

Thank you Professor Zichichi for inviting me to give a talk about AIDS-related cancers in Africa. Let me begin by congratulating the team that organized the 46th Session of the Erice International Seminar Series, whose theme is THE ROLE OF SCIENCE IN THE THIRD MILLENIUM. I also congratulate the scientists from 38 countries who are attending these seminars. They are perpetuating the principle of SCIENCE WITHOUT SECRETS in the true spirit espoused by Archimedes, Galileo, and Fermi. It is a wonderful honor for me to be here to shed some light on the health impacts of the HIV epidemic in the area of cancer...

A novel approach for blood purification: mixed-matrix membranes combining diffusion and adsorption in one step.

PubMed

Tijink, Marlon S L; Wester, Maarten; Sun, Junfen; Saris, Anno; Bolhuis-Versteeg, Lydia A M; Saiful, Saiful; Joles, Jaap A; Borneman, Zandrie; Wessling, Matthias; Stamatialis, Dimitris F

2012-07-01

Hemodialysis is a commonly used blood purification technique in patients requiring kidney replacement therapy. Sorbents could increase uremic retention solute removal efficiency but, because of poor biocompatibility, their use is often limited to the treatment of patients with acute poisoning. This paper proposes a novel membrane concept for combining diffusion and adsorption of uremic retention solutes in one step: the so-called mixed-matrix membrane (MMM). In this concept, adsorptive particles are incorporated in a macro-porous membrane layer whereas an extra particle-free membrane layer is introduced on the blood-contacting side of the membrane to improve hemocompatibility and prevent particle release. These dual-layer mixed-matrix membranes have high clean-water permeance and high creatinine adsorption from creatinine model solutions. In human plasma, the removal of creatinine and of the protein-bound solute para-aminohippuric acid (PAH) by single and dual-layer membranes is in agreement with the removal achieved by the activated carbon particles alone, showing that under these experimental conditions the accessibility of the particles in the MMM is excellent. This study proves that the combination of diffusion and adsorption in a single step is possible and paves the way for the development of more efficient blood purification devices, excellently combining the advantages of both techniques. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Global Ocean Circulation in Thermohaline Coordinates and Small-scale and Mesoscale mixing: An Inverse Estimate.

NASA Astrophysics Data System (ADS)

Groeskamp, S.; Zika, J. D.; McDougall, T. J.; Sloyan, B.

2016-02-01

I will present results of a new inverse technique that infers small-scale turbulent diffusivities and mesoscale eddy diffusivities from an ocean climatology of Salinity (S) and Temperature (T) in combination with surface freshwater and heat fluxes.First, the ocean circulation is represented in (S,T) coordinates, by the diathermohaline streamfunction. Framing the ocean circulation in (S,T) coordinates, isolates the component of the circulation that is directly related to water-mass transformation.Because water-mass transformation is directly related to fluxes of salt and heat, this framework allows for the formulation of an inverse method in which the diathermohaline streamfunction is balanced with known air-sea forcing and unknown mixing. When applying this inverse method to observations, we obtain observationally based estimates for both the streamfunction and the mixing. The results reveal new information about the component of the global ocean circulation due to water-mass transformation and its relation to surface freshwater and heat fluxes and small-scale and mesoscale mixing. The results provide global constraints on spatially varying patterns of diffusivities, in order to obtain a realistic overturning circulation. We find that mesoscale isopycnal mixing is much smaller than expected. These results are important for our understanding of the relation between global ocean circulation and mixing and may lead to improved parameterisations in numerical ocean models.

AIDS-related stigma and social interaction: Puerto Ricans living with HIV/AIDS.

PubMed

Varas-Díaz, Nelson; Serrano-García, Irma; Toro-Alfonso, José

2005-02-01

People living with HIV/AIDS are stigmatized. Although personal and social consequences of this stigmatization have been documented, research regarding its impact on social interactions is scarce. Latinos, and Puerto Ricans in particular, have voiced concern regarding AIDS stigma. The authors investigated the key role of social interaction in the process of stigmatization through in-depth, semistructured interviews in a sample of 30 Puerto Ricans living with HIV/AIDS. Participants reported instances in which AIDS stigma negatively influenced social interactions with family, friends, sexual partners, coworkers, and health professionals. Some of the consequences they described were loss of social support, persecution, isolation, job loss, and problems accessing health services. Findings support the need for interventions to address AIDS stigma and its consequences.

Factors related to the implementation and diffusion of new technologies: a pilot study

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

Not Available

1979-06-01

In order to develop an understanding of how government intervention affects the processes of implementation and diffusion of new technologies, case studies of 14 technologies were carried out: automobiles; broadcast radio; frozen foods; black and white TV; color TV; polio vaccine; supersonic transport; fluoridation of water supplies; computer-aided instruction; basic oxygen process for steel; numerical control in manufacturing; digital computers; lasers; and integrated circuit. The key factors, their motivations for implementing/adopting the technology (or not doing so), the interactions among the key factors, and how these affected implementation/adoption are examined.

Detailed flow measurements in a centrifugal compressor vaneless diffuser

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

Pinarbasi, A.; Johnson, M.W.

1994-07-01

Hot-wire anemometer measurements have been made in the vaneless diffuser of a 1-m-dia low-speed backswept centrifugal compressor using a phase lock loop technique. Radial, tangential, and axial velocity measurements have been made on eight measurement planes through the diffuser. The flow field at the diffuser entry clearly shows the impeller jet-wake flow pattern and the blade wakes. The passage wake is located on the shroud side of the diffuser and mixes out slowly as the flow moves through the diffuser. The blade wakes, on the other hand, distort and mix out rapidly in the diffuser. Contours of turbulent kinetic energymore » are also presented on each of the measurement stations, from which the regions of turbulent mixing can be deduced.« less

An Experimental Investigation of Forced Mixing of a Turbulent Boundary Layer in an Annular Diffuser. Ph.D. Thesis - Ohio State Univ.; [for boundary layer control

NASA Technical Reports Server (NTRS)

Shaw, R. J.

1979-01-01

The forced mixing process of a turbulent boundary layer in an axisymmetric annular diffuser using conventional wing-like vortex generators was studied. Flow field measurements were made at four axial locations downstream of the vortex generators. At each axial location, a total of 25 equally spaced profiles were measured behind three consecutive vortex generators which formed two pairs of vortex generators. Hot film anemometry probes measured the boundary layer turbulence structure at the same locations where pressure measurements were made. Both single and cross film probes were used. The diffuser turbulence data was teken only for a nominal inlet Mach number of 0.3. Three vortex generator configurations were tested. The differences between configurations involved changes in size and relative vortex generator positions. All three vortex generator configurations tested provided increases in diffuser performance. Distinct differences in the boundary layer integral properties and skin friction levels were noted between configurations. The axial turbulence intensity and Reynolds stress profiles measured displayed similarities in trends but differences in levels for the three configurations.

Effect of fuel composition and differential diffusion on flame stabilization in reacting syngas jets in turbulent cross-flow

DOE PAGES

Minamoto, Yuki; Kolla, Hemanth; Grout, Ray W.; ...

2015-07-24

Here, three-dimensional direct numerical simulation results of a transverse syngas fuel jet in turbulent cross-flow of air are analyzed to study the influence of varying volume fractions of CO relative to H 2 in the fuel composition on the near field flame stabilization. The mean flame stabilizes at a similar location for CO-lean and CO-rich cases despite the trend suggested by their laminar flame speed, which is higher for the CO-lean condition. To identify local mixtures having favorable mixture conditions for flame stabilization, explosive zones are defined using a chemical explosive mode timescale. The explosive zones related to flame stabilizationmore » are located in relatively low velocity regions. The explosive zones are characterized by excess hydrogen transported solely by differential diffusion, in the absence of intense turbulent mixing or scalar dissipation rate. The conditional averages show that differential diffusion is negatively correlated with turbulent mixing. Moreover, the local turbulent Reynolds number is insufficient to estimate the magnitude of the differential diffusion effect. Alternatively, the Karlovitz number provides a better indicator of the importance of differential diffusion. A comparison of the variations of differential diffusion, turbulent mixing, heat release rate and probability of encountering explosive zones demonstrates that differential diffusion predominantly plays an important role for mixture preparation and initiation of chemical reactions, closely followed by intense chemical reactions sustained by sufficient downstream turbulent mixing. The mechanism by which differential diffusion contributes to mixture preparation is investigated using the Takeno Flame Index. The mean Flame Index, based on the combined fuel species, shows that the overall extent of premixing is not intense in the upstream regions. However, the Flame Index computed based on individual contribution of H 2 or CO species reveals that hydrogen

Marital Aspirations, Sexual Behaviors, and HIV/AIDS in Rural Malawi

PubMed Central

Clark, Shelley; Poulin, Michelle; Kohler, Hans-Peter

2009-01-01

We explore how marital aspirations are related to the sexual behaviors of adolescents and young adults in Malawi, where HIV/AIDS prevalence among adults exceeds 10%. We also consider whether the specter of AIDS is shaping ideals about marriage. By combining survey data (N = 1,087) and in-depth interviews (N = 133) with young Malawians from the Malawi Diffusion and Ideational Change Project, we show that looking for and finding a suitable spouse are linked to sexual behaviors and, thus, HIV risks. Moreover, concerns about contracting HIV are closely tied to the ideal characteristics of a future spouse. Our findings draw long-overdue attention to the importance of marital aspirations in understanding adolescent sexual behaviors and risks in the era of AIDS. PMID:20161389

Scale-invariant Green-Kubo relation for time-averaged diffusivity

NASA Astrophysics Data System (ADS)

Meyer, Philipp; Barkai, Eli; Kantz, Holger

2017-12-01

In recent years it was shown both theoretically and experimentally that in certain systems exhibiting anomalous diffusion the time- and ensemble-averaged mean-squared displacement are remarkably different. The ensemble-averaged diffusivity is obtained from a scaling Green-Kubo relation, which connects the scale-invariant nonstationary velocity correlation function with the transport coefficient. Here we obtain the relation between time-averaged diffusivity, usually recorded in single-particle tracking experiments, and the underlying scale-invariant velocity correlation function. The time-averaged mean-squared displacement is given by 〈δ2¯〉 ˜2 DνtβΔν -β , where t is the total measurement time and Δ is the lag time. Here ν is the anomalous diffusion exponent obtained from ensemble-averaged measurements 〈x2〉 ˜tν , while β ≥-1 marks the growth or decline of the kinetic energy 〈v2〉 ˜tβ . Thus, we establish a connection between exponents that can be read off the asymptotic properties of the velocity correlation function and similarly for the transport constant Dν. We demonstrate our results with nonstationary scale-invariant stochastic and deterministic models, thereby highlighting that systems with equivalent behavior in the ensemble average can differ strongly in their time average. If the averaged kinetic energy is finite, β =0 , the time scaling of 〈δ2¯〉 and 〈x2〉 are identical; however, the time-averaged transport coefficient Dν is not identical to the corresponding ensemble-averaged diffusion constant.

TCL1 oncogene expression in AIDS-related lymphomas and lymphoid tissues

PubMed Central

Teitell, Michael; Damore, Michael A.; Sulur, Girija G.; Turner, Devin E.; Stern, Marc-Henri; Said, Jonathan W.; Denny, Christopher T.; Wall, Randolph

1999-01-01

AIDS-related non-Hodgkin’s lymphoma (AIDS NHL) comprises a diverse and heterogeneous group of high-grade B cell tumors. Certain classes of AIDS NHL are associated with alterations in oncogenes or tumor-suppressor genes or infections by oncogenic herpesviruses. However, the clinically significant class of AIDS NHL designated immunoblastic lymphoma plasmacytoid (AIDS IBLP) lacks any consistent genetic alterations. We identified the TCL1 oncogene from a set of AIDS IBLP-associated cDNA fragments generated by subtractive hybridization with non-AIDS IBLP. Aberrant TCL1 expression has been implicated in T cell leukemia/lymphoma development, and its expression also has been seen in many established B cell tumor lines. However, TCL1 expression has not been reported in AIDS NHL. We find that TCL1 is expressed in the majority of AIDS IBLP tumors examined. TCL1 protein expression is restricted to tumor cells in AIDS IBLP tissue samples analyzed with immunohistochemical staining. Hyperplastic lymph node and tonsil also exhibit strong TCL1 protein expression in mantle zone B cells and in rare interfollicular zone cells, whereas follicle-center B cells (centroblasts and centrocytes) show weaker expression. These results establish TCL1 as the most prevalent of all of the surveyed oncogenes associated with AIDS IBLP. They also indicate that abundant TCL1 expression in quiescent mantle zone B cells is down-regulated in activated germinal center follicular B cells in parallel to the known expression pattern of BCL-2. High-level expression in nonproliferating B cells suggests that TCL1 may function in protecting naïve preactivated B cells from apoptosis. PMID:10449776

Quantification of mixing in vesicle suspensions using numerical simulations in two dimensions.

PubMed

Kabacaoğlu, G; Quaife, B; Biros, G

2017-02-01

We study mixing in Stokesian vesicle suspensions in two dimensions on a cylindrical Couette apparatus using numerical simulations. The vesicle flow simulation is done using a boundary integral method, and the advection-diffusion equation for the mixing of the solute is solved using a pseudo-spectral scheme. We study the effect of the area fraction, the viscosity contrast between the inside (the vesicles) and the outside (the bulk) fluid, the initial condition of the solute, and the mixing metric. We compare mixing in the suspension with mixing in the Couette apparatus without vesicles. On the one hand, the presence of vesicles in most cases slightly suppresses mixing. This is because the solute can be only diffused across the vesicle interface and not advected. On the other hand, there exist spatial distributions of the solute for which the unperturbed Couette flow completely fails to mix whereas the presence of vesicles enables mixing. We derive a simple condition that relates the velocity and solute and can be used to characterize the cases in which the presence of vesicles promotes mixing.

Quantification of mixing in vesicle suspensions using numerical simulations in two dimensions

PubMed Central

Quaife, B.; Biros, G.

2017-01-01

We study mixing in Stokesian vesicle suspensions in two dimensions on a cylindrical Couette apparatus using numerical simulations. The vesicle flow simulation is done using a boundary integral method, and the advection-diffusion equation for the mixing of the solute is solved using a pseudo-spectral scheme. We study the effect of the area fraction, the viscosity contrast between the inside (the vesicles) and the outside (the bulk) fluid, the initial condition of the solute, and the mixing metric. We compare mixing in the suspension with mixing in the Couette apparatus without vesicles. On the one hand, the presence of vesicles in most cases slightly suppresses mixing. This is because the solute can be only diffused across the vesicle interface and not advected. On the other hand, there exist spatial distributions of the solute for which the unperturbed Couette flow completely fails to mix whereas the presence of vesicles enables mixing. We derive a simple condition that relates the velocity and solute and can be used to characterize the cases in which the presence of vesicles promotes mixing. PMID:28344432

Computer-aided diagnostic system for diffuse liver diseases with ultrasonography by neural networks

NASA Astrophysics Data System (ADS)

Ogawa, K.; Fukushima, M.; Kubota, K.; Hisa, N.

1998-12-01

The aim of the study is to establish a computer-aided diagnostic system for diffuse liver diseases such as chronic active hepatitis (CAH) and liver cirrhosis (LC). The authors introduced an artificial neural network in the classification of these diseases. In this system the neural network was trained by feature parameters extracted from B-mode ultrasonic images of normal liver (NL), CAH and LC. For input data the authors used six parameters calculated by a region of interest (ROI) and a parameter calculated by five ROIs in each image. They were variance of pixel values, coefficient of variation, annular Fourier power spectrum, longitudinal Fourier power spectrum which were calculated for the ROI, and variation of the means of the five ROIs. In addition, the authors used two more parameters calculated from a co-occurrence matrix of pixel values in the ROI. The results showed that the neural network classifier was 83.8% in sensitivity for LC, 90.0% in sensitivity for CAH and 93.6% in specificity, and the system was considered to be helpful for clinical and educational use.

Meta-analytic investigations of structural grey matter, executive domain-related functional activations, and white matter diffusivity in obsessive compulsive disorder: an integrative review.

PubMed

Eng, Goi Khia; Sim, Kang; Chen, Shen-Hsing Annabel

2015-05-01

Obsessive-compulsive disorder (OCD) is a debilitating disorder. However, existing neuroimaging findings involving executive function and structural abnormalities in OCD have been mixed. Here we conducted meta-analyses to investigate differences in OCD samples and controls in: Study 1 - grey matter structure; Study 2 - executive function task-related activations during (i) response inhibition, (ii) interference, and (iii) switching tasks; and Study 3 - white matter diffusivity. Results showed grey matter differences in the frontal, striatal, thalamus, parietal and cerebellar regions; task domain-specific neural differences in similar regions; and abnormal diffusivity in major white matter regions in OCD samples compared to controls. Our results reported concurrence of abnormal white matter diffusivity with corresponding abnormalities in grey matter and task-related functional activations. Our findings suggested the involvement of other brain regions not included in the cortico-striato-thalamo-cortical network, such as the cerebellum and parietal cortex, and questioned the involvement of the orbitofrontal region in OCD pathophysiology. Future research is needed to clarify the roles of these brain regions in the disorder. Copyright © 2015 Elsevier Ltd. All rights reserved.

AIDS and Adolescents: The Relation of Parent and Partner Communication to Adolescent Condom Use.

ERIC Educational Resources Information Center

Shoop, Dawn M.; Davidson, Philip M.

1994-01-01

Eighty male and female heterosexual adolescents completed questionnaires concerning sexual behavior and condom use, Acquired Immune Deficiency Syndrome (AIDS) knowledge, ability to communicate with sexual partners about AIDS-related issues, and communication with parents about sex and AIDS. Adolescents' perceived ability to communicate with…

Primary pulmonary lymphoma in a patient with advanced AIDS

PubMed Central

Shahani, Lokesh; McKenna, Megan

2014-01-01

Non-Hodgkin's lymphoma (NHL) is an AIDS defining lesion and risk of NHL most likely correlates with the degree of immunosuppression from HIV. Risk of NHL is highest among patients with CD4 count <50 cells/mL. Primary pulmonary lymphoma (PPL) is an infrequent cause of AIDS-related lymphoma. The authors report a patient with advanced AIDS presenting with recurrent fever and pulmonary nodule seen on the CT scan. The patient remained febrile despite being on broad spectrum antibiotics with no clear source of infection. The patient underwent a bronchoscopy with biopsy of the pulmonary lesion which was most consistent with diffuse large B-cell lymphoma. The patient was started on dose-adjusted etoposide, vincristine, doxorubicin, cyclophosphamide and prednisone (EPOCH) and was noted to be afebrile and a repeat CT scan few weeks later showed resolution of her pulmonary nodule. This case highlights the importance of considering NHL in patients with advanced AIDS presenting with pulmonary nodule and fever. PMID:25527680

Determination of diffusion coefficients and diffusion characteristics for chlorferon and diethylthiophosphate in Ca-alginate gel beads.

PubMed

Ha, Jiyeon; Engler, Cady R; Lee, Seung Jae

2008-07-01

Diffusion characteristics of chlorferon and diethylthiophosphate (DETP) in Ca-alginate gel beads were studied to assist in designing and operating bioreactor systems. Diffusion coefficients for chlorferon and DETP in Ca-alginate gel beads determined at conditions suitable for biodegradation studies were 2.70 x 10(-11) m(2)/s and 4.28 x 10(-11) m(2)/s, respectively. Diffusivities of chlorferon and DETP were influenced by several factors, including viscosity of the bulk solution, agitation speed, and the concentrations of diffusing substrate and immobilized cells. Diffusion coefficients increased with increasing agitation speed, probably due to poor mixing at low speed and some attrition of beads at high speeds. Diffusion coefficients also increased with decreasing substrate concentration. Increased cell concentration in the gel beads caused lower diffusivity. Theoretical models to predict diffusivities as a function of cell weight fraction overestimated the effective diffusivities for both chlorferon and DETP, but linear relations between effective diffusivity and cell weight fraction were derived from experimental data. Calcium-alginate gel beads with radii of 1.65-1.70 mm used in this study were not subject to diffusional limitations: external mass transfer resistances were negligible based on Biot number calculations and effectiveness factors indicated that internal mass transfer resistance was negligible. Therefore, the degradation rates of chlorferon and DETP inside Ca-alginate gel beads were reaction-limited. (c) 2007 Wiley Periodicals, Inc.

Circumpolar Estimates of Isopycnal Mixing in the ACC from Argo Floats

NASA Astrophysics Data System (ADS)

Roach, C. J.; Balwada, D.; Speer, K. G.

2015-12-01

There are few direct observations of cross-stream isopycnal mixing in the interior of the Southern Ocean, yet such measurements are needed to determine the role of eddies transporting properties across the ACC, and key to progress toward testing theories of meridional overturning. In light of this we examine if it is possible to obtain estimates of mixing from Argo float trajectories. We divided the Southern Ocean into overlapping 15ο longitude bins before estimating mixing. Resulting diffusivities ranged from 300 to 3000 m2s-1, with peaks corresponding to the Scotia Sea; Kerguelen and Campbell Plateaus. Comparison of our diffusivities with previous regional studies demonstrated good agreement. Tests of the methodology in the DIMES region found that mixing from Argo floats agreed closely with mixing from RAFOS floats. To further test the method we used the Southern Ocean State Estimate velocity fields to advect particles with Argo and RAFOS float like behaviours. Stirring estimates from the particles agreed well with each other in the Kerguelen Island region, South Pacific and Scotia Sea, despite the differences in the imposed behaviour. Finally, these estimates were compared to mixing length suppression theory presented in Ferrari and Nikurashin 2010. This mixing length suppression theory quantifies horizontal diffusivity similar to Prandtl (1925), but the mixing length is suppressed in the presence of mean flows and eddy phase speeds. Our results suggest that the theory can explain both the structure and magnitude of mixing using mean flow data. An exception is near the Kerguelen and Campbell Plateaus where theory under-estimates mixing relative to our results.

Computer aided diagnosis system for Alzheimer disease using brain diffusion tensor imaging features selected by Pearson's correlation.

PubMed

Graña, M; Termenon, M; Savio, A; Gonzalez-Pinto, A; Echeveste, J; Pérez, J M; Besga, A

2011-09-20

The aim of this paper is to obtain discriminant features from two scalar measures of Diffusion Tensor Imaging (DTI) data, Fractional Anisotropy (FA) and Mean Diffusivity (MD), and to train and test classifiers able to discriminate Alzheimer's Disease (AD) patients from controls on the basis of features extracted from the FA or MD volumes. In this study, support vector machine (SVM) classifier was trained and tested on FA and MD data. Feature selection is done computing the Pearson's correlation between FA or MD values at voxel site across subjects and the indicative variable specifying the subject class. Voxel sites with high absolute correlation are selected for feature extraction. Results are obtained over an on-going study in Hospital de Santiago Apostol collecting anatomical T1-weighted MRI volumes and DTI data from healthy control subjects and AD patients. FA features and a linear SVM classifier achieve perfect accuracy, sensitivity and specificity in several cross-validation studies, supporting the usefulness of DTI-derived features as an image-marker for AD and to the feasibility of building Computer Aided Diagnosis systems for AD based on them. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A mixed-order nonlinear diffusion compressed sensing MR image reconstruction.

PubMed

Joy, Ajin; Paul, Joseph Suresh

2018-03-07

Avoid formation of staircase artifacts in nonlinear diffusion-based MR image reconstruction without compromising computational speed. Whereas second-order diffusion encourages the evolution of pixel neighborhood with uniform intensities, fourth-order diffusion considers smooth region to be not necessarily a uniform intensity region but also a planar region. Therefore, a controlled application of fourth-order diffusivity function is used to encourage second-order diffusion to reconstruct the smooth regions of the image as a plane rather than a group of blocks, while not being strong enough to introduce the undesirable speckle effect. Proposed method is compared with second- and fourth-order nonlinear diffusion reconstruction, total variation (TV), total generalized variation, and higher degree TV using in vivo data sets for different undersampling levels with application to dictionary learning-based reconstruction. It is observed that the proposed technique preserves sharp boundaries in the image while preventing the formation of staircase artifacts in the regions of smoothly varying pixel intensities. It also shows reduced error measures compared with second-order nonlinear diffusion reconstruction or TV and converges faster than TV-based methods. Because nonlinear diffusion is known to be an effective alternative to TV for edge-preserving reconstruction, the crucial aspect of staircase artifact removal is addressed. Reconstruction is found to be stable for the experimentally determined range of fourth-order regularization parameter, and therefore not does not introduce a parameter search. Hence, the computational simplicity of second-order diffusion is retained. © 2018 International Society for Magnetic Resonance in Medicine.

The mental health impact of AIDS-related mortality in South Africa: a national study

PubMed Central

Myer, L; Seedat, S; Stein, D J; Moomal, H; Williams, D R

2011-01-01

Background Few data exist on how the HIV/AIDS epidemic may influence population mental health. The associations were examined between knowing someone who died of HIV/AIDS and common mental disorders among South African adults. Methods Between 2002 and 2004, a nationally representative sample of 4351 adults were interviewed about personally knowing someone who died of HIV/AIDS, and the World Health Organization Composite International Diagnostic Interview was used to generate psychiatric diagnoses for depression, anxiety and substance abuse disorders during the preceding 12 months based on the Diagnostic and Statistical Manual, 4th edition (DSM-IV). Results Overall, 42.2% of the sample knew someone who died of HIV/AIDS, and 16.5% met the criteria for at least one DSM-IV diagnosis. Individuals who knew someone who died of HIV/AIDS were significantly more likely to have any DSM-IV defined disorder, including any depressive, anxiety or substance-related disorder (p<0.001 for all associations). In multivariate models adjusted for participant demographic characteristics, life events and socioeconomic status, individual disorders significantly associated with knowing someone who died of HIV/AIDS included generalised anxiety disorder, social phobia and alcohol/drug dependence or abuse. Based on these results, it is estimated that up to 15% of 12-month DSM-IV disorders in the South African adult population may be related to knowing someone who died of HIV/AIDS. Conclusion These novel data suggest that AIDS-related mortality may contribute substantially to the burden of mental disorders in settings of high HIV prevalence. While this finding requires further investigation, these data suggest the need to strengthen mental health services in communities where HIV/AIDS is prevalent. PMID:19074926

Flux-related and Critical Dilution Indices: Quantitative Indicators of Mixing and Mixing-controlled Reactions in Heterogeneous Porous Media

NASA Astrophysics Data System (ADS)

Chiogna, G.; Cirpka, O. A.; Grathwohl, P.; Rolle, M.

2010-12-01

The correct quantification of mixing is of utmost importance for modeling reactive transport in porous media and, thereby assessing the fate and transport of contaminants in the subsurface. An appropriate measure of mixing in heterogeneous porous formations should correctly capture the effects on mixing intensity of various processes at different scales, such as local dispersion and the effect of mixing enhancement due to heterogeneities. In this work, we use the concept of the flux-related dilution index as a measure of transverse mixing. This quantity expresses the dilution of the mass flux of a tracer solution over the total discharge of the system and is particularly suited to address problems where a compound is continuously injected into the domain. We focus our attention on two-dimensional systems under steady-state flow conditions and investigate both conservative and reactive transport in both homogeneous and heterogeneous porous media at different scales. For mixing-controlled reactive systems, we introduce and illustrate the concept of the critical dilution index, which represents the amount of mixing required for complete degradation of a continuously emitted plume undergoing decay upon mixing with ambient water. We perform two-dimensional numerical experiments at bench and field scales in homogeneous and heterogeneous conductivity fields. These numerical simulations show that the flux-related dilution index quantifies mixing and that the concept of the critical dilution index is a useful measure to relate the mixing of conservative tracers to mixing-controlled turnover of reactive compounds. In the end we define an effective transverse dispersion coefficient which is able to capture the main characteristics of the physical mechanisms controlling reactive transport at the field scale. Furthermore we investigated the influence of compound specific local transverse dispersion coefficients on the flux related dilution index and on the critical dilution

Recent development of a jet-diffuser ejector

NASA Technical Reports Server (NTRS)

Alperin, M.; Wu, J. J.

1980-01-01

The paper considers thrust augmenting ejectors in which the processes of mixing and diffusion are partly carried out downstream of the ejector solid surfaces. A jet sheet surrounding the periphery of a widely diverging diffuser prevents separation and forms a gaseous, curved surface to provide effective diffuser ratio and additional length for mixing of primary and induced flows. Three-dimensional potential flow methods achieved a large reduction in the length of the associated solid surface; primary nozzle design further reduced the volume required by the jet-diffuser ejectors, resulting in thrust augmentation in excess of two, and an overall length of about 2 1/2 times the throat width.

Core indicators evaluation of effectiveness of HIV-AIDS preventive-control programmes carried out by nongovernmental organizations. A mixed method study

PubMed Central

2011-01-01

Background The number of nongovernmental organizations working on AIDS has grown. There is great diversity in the type of activities and population groups that have been targeted. The purposes of this study are: to describe and analyze the objectives and HIV-AIDS preventive activities that are carried out by the AIDS-NGOs that work with AIDS in Catalonia and that receive subsidies from the Department of Health; and to develop a comprehensive proposal for measurable and agreed upon core quality evaluation indicators to monitor and assess those objectives and activities that can have an impact on the fight against inequalities and stigmatization, and incorporate the perspectives of the service providers and users. Methods A mixed method study has been carried out with professionals from the 36 NGOs that work with HIV/AIDS in Catalonia, as well as their users. This study achieved the completeness model using the following phases: 1. A systematic review of AIDS-NGOs annual reports and preparation of a catalogue of activities grouped by objectives, level of prevention and AIDS-NGOs target population; 2. A transversal study through an ad-hoc questionnaire administered to the AIDS-NGOs representatives; 3. A qualitative study with a phenomenological approach through focus groups, individual interviews and observations; 4. Consensus meetings between AIDS-NGOs professionals and the research team using Haddon matrices in order to establish a proposal of evaluation indicators. Results The information was classified according to level of prevention and level of intervention. A total of 248 objectives and 258 prevention activities were identified. 1564 evaluation indicators, addressed to 7 target population groups, were produced. Thirty core activities were selected. The evaluation indicators proposed for these activities were: 76 indicators for 15 primary prevention activities, 43 for 5 secondary prevention activities and 68 for 10 tertiary prevention activities. Conclusions

Core indicators evaluation of effectiveness of HIV-AIDS preventive-control programmes carried out by nongovernmental organizations. A mixed method study.

PubMed

Berenguera, Anna; Pujol-Ribera, Enriqueta; Violan, Concepció; Romaguera, Amparo; Mansilla, Rosa; Giménez, Albert; Ascaso, Carlos; Almeda, Jesús

2011-07-28

The number of nongovernmental organizations working on AIDS has grown. There is great diversity in the type of activities and population groups that have been targeted. The purposes of this study are: to describe and analyze the objectives and HIV-AIDS preventive activities that are carried out by the AIDS-NGOs that work with AIDS in Catalonia and that receive subsidies from the Department of Health; and to develop a comprehensive proposal for measurable and agreed upon core quality evaluation indicators to monitor and assess those objectives and activities that can have an impact on the fight against inequalities and stigmatization, and incorporate the perspectives of the service providers and users. A mixed method study has been carried out with professionals from the 36 NGOs that work with HIV/AIDS in Catalonia, as well as their users. This study achieved the completeness model using the following phases:1. A systematic review of AIDS-NGOs annual reports and preparation of a catalogue of activities grouped by objectives, level of prevention and AIDS-NGOs target population; 2. A transversal study through an ad-hoc questionnaire administered to the AIDS-NGOs representatives; 3. A qualitative study with a phenomenological approach through focus groups, individual interviews and observations; 4. Consensus meetings between AIDS-NGOs professionals and the research team using Haddon matrices in order to establish a proposal of evaluation indicators. The information was classified according to level of prevention and level of intervention. A total of 248 objectives and 258 prevention activities were identified. 1564 evaluation indicators, addressed to 7 target population groups, were produced. Thirty core activities were selected. The evaluation indicators proposed for these activities were: 76 indicators for 15 primary prevention activities, 43 for 5 secondary prevention activities and 68 for 10 tertiary prevention activities. The results could help to homogeneously

Turbulent mixing and removal of ozone within an Amazon rainforest canopy

NASA Astrophysics Data System (ADS)

Freire, L. S.; Gerken, T.; Ruiz-Plancarte, J.; Wei, D.; Fuentes, J. D.; Katul, G. G.; Dias, N. L.; Acevedo, O. C.; Chamecki, M.

2017-03-01

Simultaneous profiles of turbulence statistics and mean ozone mixing ratio are used to establish a relation between eddy diffusivity and ozone mixing within the Amazon forest. A one-dimensional diffusion model is proposed and used to infer mixing time scales from the eddy diffusivity profiles. Data and model results indicate that during daytime conditions, the upper (lower) half of the canopy is well (partially) mixed most of the time and that most of the vertical extent of the forest can be mixed in less than an hour. During nighttime, most of the canopy is predominantly poorly mixed, except for periods with bursts of intermittent turbulence. Even though turbulence is faster than chemistry during daytime, both processes have comparable time scales in the lower canopy layers during nighttime conditions. Nonchemical loss time scales (associated with stomatal uptake and dry deposition) for the entire forest are comparable to turbulent mixing time scale in the lower canopy during the day and in the entire canopy during the night, indicating a tight coupling between turbulent transport and dry deposition and stomatal uptake processes. Because of the significant time of day and height variability of the turbulent mixing time scale inside the canopy, it is important to take it into account when studying chemical and biophysical processes happening in the forest environment. The method proposed here to estimate turbulent mixing time scales is a reliable alternative to currently used models, especially for situations in which the vertical distribution of the time scale is relevant.

[Implementation of intervention programs on AIDS-related sexual transmission in China].

PubMed

Dong, Wei; Zhou, Chu; Ge, Lin; Li, Dongmin; Wu, Zunyou; Rou, Keming

2015-12-01

To analyze the implementation of intervention programs targeted on AIDS high risk sexual transmission groups since 2008, when the relative prevention and control information systems on HIV/AIDS were developed. Data from both aggregated interventions and sentinel surveillance programs from 2008 to the end of 2014 were used. Descriptive statistics were performed to analyze the trends of implementation on high risk groups including men who have sex with men, female sex workers (FSW) and migrant workers. From 2008 to 2012, the monthly average numbers receiving intervention programs and the average monthly coverage rate on intervention for MSM, increased from 49 000 to 252 000, and from 8.6% to 78.5% respectively. The FSW related indicators increased from 329 000 to 625 000, and from 30.9% to 87.0% respectively. Above indexes on the two populations had dropped slightly in 2013 and 2014. Sentinel surveillance data showed that knowledge and behavior indicators observed from the MSM and FSW populations increased annually. The coverage of intervention programs on migrant workers increased from 4.7% to almost 10.0%, but the surveillance data on migrant men showed that the knowledge and behavior indicators were still lower than the other high-risk groups. Intervention related to sexual transmission on HIV/AIDS among high-risk populations were effectively implemented, with some achievements seen. However, as sexual contact currently became the main route of AIDS epidemic, new challenges called for serious attention.

Enhancing the effectiveness of HIV/AIDS prevention programs targeted to unique population groups in Thailand: lessons learned from applying concepts of diffusion of innovation and social marketing.

PubMed

Svenkerud, P J; Singhal, A

1998-01-01

Diffusion of innovations theory and social marketing theory have been criticized for their limited applicability in influencing unique population groups (e.g., female commercial sex workers (CSWs) working in low-class brothels). This study investigated the applicability of these two theoretical frameworks in outreach efforts directed to unique populations at high risk for HIV/AIDS in Bangkok, Thailand. Further, this study examined Thai cultural characteristics that influence communication about HIV/AIDS prevention. The results suggest that certain concepts and strategies drawn from the two frameworks were used more or less by effective outreach programs, providing several policy-relevant lessons. Cultural constraints, such as the lack of visibility of the disease and traditional sexual practices, influenced communication about HIV/AIDS prevention.

Knowledge levels of pre-school teachers related with basic first-aid practices, Isparta sample.

PubMed

Sönmez, Yonca; Uskun, Ersin; Pehlivan, Azize

2014-09-01

The aim of this study was to evaluate the levels of knowledge of pre-school teachers working in the province center of Isparta related with basic first-aid practices and some factors which affected these levels of knowledge. In this cross-sectional, analytic study, 110 pre-school teachers working in the province center of Isparta constituted the population. A questionnaire questioning sociodemographic properties and the level of knowledge related with first-aid practices was applied under supervision. The level of knowledge was evaluated on a 20-point scale. In the analyses, Kruskal-Wallis and Mann-Whitney U tests and Spearman's rank correlation were used. The study was approved by the Ethical Committee for Clinical Studies of Süleyman Demirel University School of Medicine (registration number: 105). The mean score of first-aid knowledge of the pre-school teachers was found to be 11.9±2.9. The least known issues included washing the wound by soap and water after a dog bite, information related with the necessity of immobilization of a child who has fallen from a high level and the phone number of National Poison Information Center (16.4%, 20.9% and 22.7%, respectively). The scores of the subjects whose knowledge of first-aid was evaluated to be well were higher compared to the subjects whose knowledge of first-aid was evaluated to be moderate (p=0.009) and poor (p=0.001). It was found that first-aid scores did not show significant difference in terms of age, working period, having received first-aid training and having faced with a condition requiring first-aid previously (p>0.05, for all comparisons). It was found that pre-school teachers had insufficient first-aid knowledge. Since the first-aid knowledge scores of the subjects who reported that they received first-aid training before did not show significant difference, it was thought that the quality of training was as important as receiving training.

Certified Nurses' Aide Job-Related Curriculum.

ERIC Educational Resources Information Center

Massachusetts Career Development Inst., Springfield.

This document, which is designed for students preparing to become a certified nurses' aide, contains instructional text and learning activities organized in nine sections. The following topics are covered: the role of the certified nurse's aide (job duties, personal health, professionalism, code of ethics); infection control (the infection…

Lagrangian particles with mixing. I. Simulating scalar transport

NASA Astrophysics Data System (ADS)

Klimenko, A. Y.

2009-06-01

The physical similarity and mathematical equivalence of continuous diffusion and particle random walk forms one of the cornerstones of modern physics and the theory of stochastic processes. The randomly walking particles do not need to posses any properties other than location in physical space. However, particles used in many models dealing with simulating turbulent transport and turbulent combustion do posses a set of scalar properties and mixing between particle properties is performed to reflect the dissipative nature of the diffusion processes. We show that the continuous scalar transport and diffusion can be accurately specified by means of localized mixing between randomly walking Lagrangian particles with scalar properties and assess errors associated with this scheme. Particles with scalar properties and localized mixing represent an alternative formulation for the process, which is selected to represent the continuous diffusion. Simulating diffusion by Lagrangian particles with mixing involves three main competing requirements: minimizing stochastic uncertainty, minimizing bias introduced by numerical diffusion, and preserving independence of particles. These requirements are analyzed for two limited cases of mixing between two particles and mixing between a large number of particles. The problem of possible dependences between particles is most complicated. This problem is analyzed using a coupled chain of equations that has similarities with Bogolubov-Born-Green-Kirkwood-Yvon chain in statistical physics. Dependences between particles can be significant in close proximity of the particles resulting in a reduced rate of mixing. This work develops further ideas introduced in the previously published letter [Phys. Fluids 19, 031702 (2007)]. Paper I of this work is followed by Paper II [Phys. Fluids 19, 065102 (2009)] where modeling of turbulent reacting flows by Lagrangian particles with localized mixing is specifically considered.

Rapid microfluidic mixing.

PubMed

Johnson, Timothy J; Ross, David; Locascio, Laurie E

2002-01-01

A preformed T-microchannel imprinted in polycarbonate was postmodified with a pulsed UV excimer laser (KrF, 248 nm) to create a series of slanted wells at the junction. The presence of the wells leads to a high degree of lateral transport within the channel and rapid mixing of two confluent streams undergoing electroosmotic flow. Several mixer designs were fabricated and investigated. All designs were relatively successful at low flow rates (0.06 cm/s, > or = 75% mixing), but had varying degrees of success at high flow rates (0.81 cm/s, 45-80% mixing). For example, one design operating at high flow rates was able to split an incoming fluorescent stream into two streams of varying concentrations depending on the number of slanted wells present. The final mixer design was able to overcome stream splitting at high flow rates, and it was shown that the two incoming streams were 80% mixed within 443 microm of the T-junction for a flow rate of 0.81 cm/s. Without the presence of the mixer and at the same high flow rate, a channel length of 2.3 cm would be required to achieve the same extent of mixing when relying upon molecular diffusion entirely, while 6.9 cm would be required for 99% mixing.

Turbulent transport and mixing in transitional Rayleigh-Taylor unstable flow: A priori assessment of gradient-diffusion and similarity modeling

NASA Astrophysics Data System (ADS)

Schilling, Oleg; Mueschke, Nicholas J.

2017-12-01

Data from a 1152 ×760 ×1280 direct numerical simulation [N. J. Mueschke and O. Schilling, Phys. Fluids 21, 014106 (2009), 10.1063/1.3064120] of a Rayleigh-Taylor mixing layer modeled after a small-Atwood-number water-channel experiment is used to investigate the validity of gradient diffusion and similarity closures a priori. The budgets of the mean flow, turbulent kinetic energy, turbulent kinetic energy dissipation rate, heavy-fluid mass fraction variance, and heavy-fluid mass fraction variance dissipation rate transport equations across the mixing layer were previously analyzed [O. Schilling and N. J. Mueschke, Phys. Fluids 22, 105102 (2010), 10.1063/1.3484247] at different evolution times to identify the most important transport and mixing mechanisms. Here a methodology is introduced to systematically estimate model coefficients as a function of time in the closures of the dynamically significant terms in the transport equations by minimizing the L2 norm of the difference between the model and correlations constructed using the simulation data. It is shown that gradient-diffusion and similarity closures used for the turbulent kinetic energy K , turbulent kinetic energy dissipation rate ɛ , heavy-fluid mass fraction variance S , and heavy-fluid mass fraction variance dissipation rate χ equations capture the shape of the exact, unclosed profiles well over the nonlinear and turbulent evolution regimes. Using order-of-magnitude estimates [O. Schilling and N. J. Mueschke, Phys. Fluids 22, 105102 (2010), 10.1063/1.3484247] for the terms in the exact transport equations and their closure models, it is shown that several of the standard closures for the turbulent production and dissipation (destruction) must be modified to include Reynolds-number scalings appropriate for Rayleigh-Taylor flow at small to intermediate Reynolds numbers. The late-time, large Reynolds number coefficients are determined to be different from those used in shear flow applications and

Diffusion through Pig Gastric Mucin: Effect of Relative Humidity

PubMed Central

Runnsjö, Anna; Dabkowska, Aleksandra P.; Sparr, Emma; Kocherbitov, Vitaly; Arnebrant, Thomas; Engblom, Johan

2016-01-01

Mucus covers the epithelium found in all intestinal tracts, where it serves as an important protecting barrier, and pharmaceutical drugs administrated by the oral, rectal, vaginal, ocular, or nasal route need to penetrate the mucus in order to reach their targets. Furthermore, the diffusion in mucus as well as the viscosity of mucus in the eyes, nose and throat can change depending on the relative humidity of the surrounding air. In this study we have investigated how diffusion through gels of mucin, the main protein in mucus, is affected by changes in ambient relative humidity (i.e. water activity). Already a small decrease in water activity was found to give rise to a significant decrease in penetration rate through the mucin gel of the antibacterial drug metronidazole. We also show that a decrease in water activity leads to decreased diffusion rate in the mucin gel for the fluorophore fluorescein. This study shows that it is possible to alter transport rates of molecules through mucus by changing the water activity in the gel. It furthermore illustrates the importance of considering effects of the water activity in the mucosa during development of potential pharmaceuticals. PMID:27336158

HIV/AIDS Related Stigma and Discrimination against PLWHA in Nigerian Population

PubMed Central

Bulgiba, Awang; Oche, Oche Mansur; Adekunjo, Felix Oluyemi

2015-01-01

Background HIV/AIDS remain a major public health concern in Nigeria. People living with HIV/AIDS (PLWHA) face not only personal medical problems but also social problems associated with the disease such as stigma and discriminatory attitudes. This study provides an insight into HIV/AIDS related stigma and discrimination against PLWHA in Nigeria. Methods The data for this study was extracted from the 2013 Nigeria Demographic and Health Survey conducted by the National Population Commission. All men and women aged 15–49 years, permanent residents and visitors of the households were eligible for the interview. Several questionnaires were used in the survey, some covering questions on HIV/AIDS. Results A total of 56 307 men and women aged 15–49 years participated in this national survey. About half of the population in Nigeria have HIV stigma. Younger persons, men, those without formal education and those within poor wealth index are more likely to have stigma towards PLWHA. In addition, married people are more likely to have stigma on PLWHA and are more likely to blame PLWHA for bringing the disease to the community. Also about half of the population discriminates against PLWHA. However, those with higher levels of education and those from higher wealth index seem to be more compassionate towards PLWHA. About 70% in the population are willing to care for relative with AIDS, even more so among those with higher level of education. Conclusion There is a high level of HIV stigma and discrimination against PLWHA in the Nigerian population. Education seems to play a major role in the society with respect to HIV stigma and discrimination against PLWHA. Educating the population with factual information on HIV/AIDS is needed to reduce stigma and discrimination towards PLWHA in the community. PMID:26658767

HIV/AIDS Related Stigma and Discrimination against PLWHA in Nigerian Population.

PubMed

Dahlui, Maznah; Azahar, Nazar; Bulgiba, Awang; Zaki, Rafdzah; Oche, Oche Mansur; Adekunjo, Felix Oluyemi; Chinna, Karuthan

2015-01-01

HIV/AIDS remain a major public health concern in Nigeria. People living with HIV/AIDS (PLWHA) face not only personal medical problems but also social problems associated with the disease such as stigma and discriminatory attitudes. This study provides an insight into HIV/AIDS related stigma and discrimination against PLWHA in Nigeria. The data for this study was extracted from the 2013 Nigeria Demographic and Health Survey conducted by the National Population Commission. All men and women aged 15-49 years, permanent residents and visitors of the households were eligible for the interview. Several questionnaires were used in the survey, some covering questions on HIV/AIDS. A total of 56 307 men and women aged 15-49 years participated in this national survey. About half of the population in Nigeria have HIV stigma. Younger persons, men, those without formal education and those within poor wealth index are more likely to have stigma towards PLWHA. In addition, married people are more likely to have stigma on PLWHA and are more likely to blame PLWHA for bringing the disease to the community. Also about half of the population discriminates against PLWHA. However, those with higher levels of education and those from higher wealth index seem to be more compassionate towards PLWHA. About 70% in the population are willing to care for relative with AIDS, even more so among those with higher level of education. There is a high level of HIV stigma and discrimination against PLWHA in the Nigerian population. Education seems to play a major role in the society with respect to HIV stigma and discrimination against PLWHA. Educating the population with factual information on HIV/AIDS is needed to reduce stigma and discrimination towards PLWHA in the community.

Paclitaxel is safe and effective in the treatment of advanced AIDS-related Kaposi's sarcoma.

PubMed

Gill, P S; Tulpule, A; Espina, B M; Cabriales, S; Bresnahan, J; Ilaw, M; Louie, S; Gustafson, N F; Brown, M A; Orcutt, C; Winograd, B; Scadden, D T

1999-06-01

Liposomal anthracyclines are the present standard treatment for advanced AIDS-related Kaposi's sarcoma (KS). No effective therapies have been defined for use after treatment failure of these agents. A phase II trial was thus conducted with paclitaxel in patients with advanced KS to assess safety and antitumor activity. A regimen of paclitaxel at a dose of 100 mg/m(2) was given every 2 weeks to patients with advanced AIDS-related KS. Patients were treated until complete remission, disease progression, or unacceptable toxicity occurred. Fifty-six patients with advanced AIDS-related KS were accrued. Tumor-associated edema was present in 70% of patients and visceral involvement in 45%. Forty patients (71%) had received prior systemic therapy; 31 of these were resistant to an anthracycline. The median entry CD4(+) lymphocyte count was 20 cells/mm(3) (range, 0 to 358). A median of 10 cycles (range, 1 to 54+) of paclitaxel was administered. Fifty-nine percent of patients showed complete (n = 1) or partial response (n = 32) to paclitaxel. The median duration of response was 10.4 months (range, 2.8 to 26.7+ months) and the median survival was 15.4 months. The main side effects of therapy were grade 3 or 4 neutropenia in 61% of patients and mild-to-moderate alopecia in 87%. Paclitaxel at 100 mg/m(2) given every 2 weeks is active and well tolerated in the treatment of advanced and previously treated AIDS-related KS. The median duration of response is among the longest observed for any regimen or single agent reported for AIDS-related KS. Paclitaxel at this dosage and schedule is a treatment option for patients with advanced AIDS-related KS, including those who have experienced treatment failure of prior systemic therapy.

[AIDS-related early mortality in Mexico between 2008 and 2012].

PubMed

Silverman-Retana, Omar; Bautista-Arredondo, Sergio; Serván-Mori, Edson; Lozano, Rafael

2015-01-01

To describe the distribution of AIDS-related mortality according to the time of occurrence since entry to the System for the Administration, Logistics and Surveillance of Antiretrovirals (SALVAR, in Spanish), among users of Ministry of Health facilities in Mexico. Descriptive analysis of AIDS mortality and the related clinical and demographic profile of 41847 patients registered in SALVAR. 3195 patients (8.1%) died within the study period, 59% of these deaths occurred within six months after treatment initiation. Among those patients, 87.3% were diagnosed late, given their CD4 levels (CD4cel<200 cel/ml³). Our results underscore the need to strengthen programs aimed to increase opportune HIV diagnosis and linkage to care, as a key component of universal access policy to antiretroviral treatment in Mexico.

Transport and mixing in strongly coupled dusty plasma medium

NASA Astrophysics Data System (ADS)

Dharodi, Vikram; Das, Amita; Patel, Bhavesh

2016-10-01

The generalized hydrodynamic (GHD) fluid model has been employed to study the transport and mixing properties of Dusty plasma medium in strong coupling limit. The response of lighter electron and ion species to the dust motion is taken to be instantaneous i.e. inertia-less. Thus the electron and ion density are presumed to follow the Boltzman relation. In the incompressible limit (i-GHD) the model supports Transverse Shear wave in contrast to the Hydrodynamic fluids. It has been shown that the presence of these waves leads to a better mixing of fluid in this case. Several cases of flow configuration have been considered for the study. The transport and mixing attributes have been quantified by studying the dynamical evolution of tracer particles in the system. The diffusion and clustering of these test particles are directly linked to the mixing characteristic of a medium. The displacement of these particles provides for a quantitative estimate of the diffusion coefficient of the medium. It is shown that these test particles often organize themselves in spatially inhomogeneous pattern leading to the phenomena of clustering.

AIDS-related health behavior: coping, protection motivation, and previous behavior.

PubMed

Van der Velde, F W; Van der Pligt, J

1991-10-01

The purpose of this study was to examine Rogers' protection motivation theory and aspects of Janis and Mann's conflict theory in the context of AIDS-related health behavior. Subjects were 84 heterosexual men and women and 147 homosexual men with multiple sexual partners; LISREL's path-analysis techniques were used to evaluate the goodness of fit of the structural equation models. Protection motivation theory did fit the data but had considerably more explanatory power for heterosexual than for homosexual subjects (49 vs. 22%, respectively). When coping styles were added, different patterns of findings were found among both groups. Adding variables such as social norms and previous behavior increased the explained variance to 73% for heterosexual subjects and to 44% for homosexual subjects. It was concluded that although protection motivation theory did fit the data fairly adequately, expanding the theory with other variables--especially those related to previous behavior--could improve our understanding of AIDS-related health behavior.

Numerical simulations of short-mixing-time double-wave-vector diffusion-weighting experiments with multiple concatenations on whole-body MR systems

NASA Astrophysics Data System (ADS)

Finsterbusch, Jürgen

2010-12-01

Double- or two-wave-vector diffusion-weighting experiments with short mixing times in which two diffusion-weighting periods are applied in direct succession, are a promising tool to estimate cell sizes in the living tissue. However, the underlying effect, a signal difference between parallel and antiparallel wave vector orientations, is considerably reduced for the long gradient pulses required on whole-body MR systems. Recently, it has been shown that multiple concatenations of the two wave vectors in a single acquisition can double the modulation amplitude if short gradient pulses are used. In this study, numerical simulations of such experiments were performed with parameters achievable with whole-body MR systems. It is shown that the theoretical model yields a good approximation of the signal behavior if an additional term describing free diffusion is included. More importantly, it is demonstrated that the shorter gradient pulses sufficient to achieve the desired diffusion weighting for multiple concatenations, increase the signal modulation considerably, e.g. by a factor of about five for five concatenations. Even at identical echo times, achieved by a shortened diffusion time, a moderate number of concatenations significantly improves the signal modulation. Thus, experiments on whole-body MR systems may benefit from multiple concatenations.

HIV Stigma and Its Relation to Mental, Physical and Social Health Among Black Women Living with HIV/AIDS.

PubMed

Travaglini, Letitia E; Himelhoch, Seth S; Fang, Li Juan

2018-02-07

Black women living with HIV/AIDS (LWHA) are a subgroup with the highest growing rates of HIV infection in the United States. Stigma and co-occurring mental and physical health problems have been reported among Black women LWHA, and research on the benefits of social and religious support, often major protective factors among Black women, has been met with mixed findings. The current study examined the relation between anticipated HIV stigma and mental and physical health symptoms and risk and protective factors (discrimination, coping, social support) among Black women LWHA (N = 220). Results showed that greater anticipated stigma was significantly related to poorer mental health status, greater discrimination, and greater use of negative coping strategies. Stigma was not related to physical health, perceived social support or use of positive coping strategies. This study lends support to the need for psychosocial interventions that reduce anticipated stigma among individuals LWHA, particularly Black women LWHA.

The special theory of Brownian relativity: equivalence principle for dynamic and static random paths and uncertainty relation for diffusion.

PubMed

Mezzasalma, Stefano A

2007-03-15

The theoretical basis of a recent theory of Brownian relativity for polymer solutions is deepened and reexamined. After the problem of relative diffusion in polymer solutions is addressed, its two postulates are formulated in all generality. The former builds a statistical equivalence between (uncorrelated) timelike and shapelike reference frames, that is, among dynamical trajectories of liquid molecules and static configurations of polymer chains. The latter defines the "diffusive horizon" as the invariant quantity to work with in the special version of the theory. Particularly, the concept of universality in polymer physics corresponds in Brownian relativity to that of covariance in the Einstein formulation. Here, a "universal" law consists of a privileged observation, performed from the laboratory rest frame and agreeing with any diffusive reference system. From the joint lack of covariance and simultaneity implied by the Brownian Lorentz-Poincaré transforms, a relative uncertainty arises, in a certain analogy with quantum mechanics. It is driven by the difference between local diffusion coefficients in the liquid solution. The same transformation class can be used to infer Fick's second law of diffusion, playing here the role of a gauge invariance preserving covariance of the spacetime increments. An overall, noteworthy conclusion emerging from this view concerns the statistics of (i) static macromolecular configurations and (ii) the motion of liquid molecules, which would be much more related than expected.

Mixed membership trajectory models of cognitive impairment in the multicenter AIDS cohort study.

PubMed

Molsberry, Samantha A; Lecci, Fabrizio; Kingsley, Lawrence; Junker, Brian; Reynolds, Sandra; Goodkin, Karl; Levine, Andrew J; Martin, Eileen; Miller, Eric N; Munro, Cynthia A; Ragin, Ann; Sacktor, Ned; Becker, James T

2015-03-27

The longitudinal trajectories that individuals may take from a state of normal cognition to HIV-associated dementia are unknown. We applied a novel statistical methodology to identify trajectories to cognitive impairment, and factors that affected the 'closeness' of an individual to one of the canonical trajectories. The Multicenter AIDS Cohort Study (MACS) is a four-site longitudinal study of the natural and treated history of HIV disease among gay and bisexual men. Using data from 3892 men (both HIV-infected and HIV-uninfected) enrolled in the neuropsychology substudy of the MACS, a Mixed Membership Trajectory Model (MMTM) was applied to capture the pathways from normal cognitive function to mild impairment to severe impairment. MMTMs allow the data to identify canonical pathways and to model the effects of risk factors on an individual's 'closeness' to these trajectories. First, we identified three distinct trajectories to cognitive impairment: 'normal aging' (low probability of mild impairment until age 60); 'premature aging' (mild impairment starting at age 45-50); and 'unhealthy' (mild impairment in 20s and 30s) profiles. Second, clinically defined AIDS, and not simply HIV disease, was associated with closeness to the premature aging trajectory, and, third, hepatitis-C infection, depression, race, recruitment cohort and confounding conditions all affected individual's closeness to these trajectories. These results provide new insight into the natural history of cognitive dysfunction in HIV disease and provide evidence for a potential difference in the pathophysiology of the development of cognitive impairment based on trajectories to impairment.

An Experiment Investigation of Fully-Modulated, Turbulent Diffusion Flames in Reduced Gravity

NASA Technical Reports Server (NTRS)

Hermanson, J. C.; Johari, H.; Usowicz, J. E.; Stocker, D. P.; Nagashima, T.; Obata, S.

1999-01-01

Pulsed combustion appears to have the potential to provide for rapid fuel/air mixing, compact and economical combustors, and reduced exhaust emissions. The ultimate objective of this program is to increase the fundamental understanding of the fuel/air mixing and combustion behavior of pulsed, turbulent diffusion flames by conducting experiments in microgravity. In this research the fuel jet is fully-modulated (i.e., completely shut off between pulses) by an externally controlled valve system. This can give rise to drastic modification of the combustion and flow characteristics of flames, leading to enhanced fuel/air mixing mechanisms not operative for the case of acoustically excited or partially-modulated jets. In addition, the fully-modulated injection approach avoids the strong acoustic forcing present in pulsed combustion devices, significantly simplifying the mixing and combustion processes. Relatively little is known of the behavior of turbulent flames in reduced-gravity conditions, even in the absence of pulsing. The goal of this Flight-Definition experiment (PUFF, for PUlsed-Fully Flames) is to establish the behavior of fully-modulated, turbulent diffusion flames under microgravity conditions. Fundamental issues to be addressed in this experiment include the mechanisms responsible for the flame length decrease for fully-modulated, turbulent diffusion flames compared with steady flames, the impact of buoyancy on the mixing and combustion characteristics of these flames, and the characteristics of turbulent flame puffs under fully momentum-dominated conditions.

Modeling of molecular diffusion and thermal conduction with multi-particle interaction in compressible turbulence

NASA Astrophysics Data System (ADS)

Tai, Y.; Watanabe, T.; Nagata, K.

2018-03-01

A mixing volume model (MVM) originally proposed for molecular diffusion in incompressible flows is extended as a model for molecular diffusion and thermal conduction in compressible turbulence. The model, established for implementation in Lagrangian simulations, is based on the interactions among spatially distributed notional particles within a finite volume. The MVM is tested with the direct numerical simulation of compressible planar jets with the jet Mach number ranging from 0.6 to 2.6. The MVM well predicts molecular diffusion and thermal conduction for a wide range of the size of mixing volume and the number of mixing particles. In the transitional region of the jet, where the scalar field exhibits a sharp jump at the edge of the shear layer, a smaller mixing volume is required for an accurate prediction of mean effects of molecular diffusion. The mixing time scale in the model is defined as the time scale of diffusive effects at a length scale of the mixing volume. The mixing time scale is well correlated for passive scalar and temperature. Probability density functions of the mixing time scale are similar for molecular diffusion and thermal conduction when the mixing volume is larger than a dissipative scale because the mixing time scale at small scales is easily affected by different distributions of intermittent small-scale structures between passive scalar and temperature. The MVM with an assumption of equal mixing time scales for molecular diffusion and thermal conduction is useful in the modeling of the thermal conduction when the modeling of the dissipation rate of temperature fluctuations is difficult.

HIV/AIDS-related mortality in Africa and Asia: evidence from INDEPTH health and demographic surveillance system sites.

PubMed

Streatfield, P Kim; Khan, Wasif A; Bhuiya, Abbas; Hanifi, Syed M A; Alam, Nurul; Millogo, Ourohiré; Sié, Ali; Zabré, Pascal; Rossier, Clementine; Soura, Abdramane B; Bonfoh, Bassirou; Kone, Siaka; Ngoran, Eliezer K; Utzinger, Juerg; Abera, Semaw F; Melaku, Yohannes A; Weldearegawi, Berhe; Gomez, Pierre; Jasseh, Momodou; Ansah, Patrick; Azongo, Daniel; Kondayire, Felix; Oduro, Abraham; Amu, Alberta; Gyapong, Margaret; Kwarteng, Odette; Kant, Shashi; Pandav, Chandrakant S; Rai, Sanjay K; Juvekar, Sanjay; Muralidharan, Veena; Wahab, Abdul; Wilopo, Siswanto; Bauni, Evasius; Mochamah, George; Ndila, Carolyne; Williams, Thomas N; Khagayi, Sammy; Laserson, Kayla F; Nyaguara, Amek; Van Eijk, Anna M; Ezeh, Alex; Kyobutungi, Catherine; Wamukoya, Marylene; Chihana, Menard; Crampin, Amelia; Price, Alison; Delaunay, Valérie; Diallo, Aldiouma; Douillot, Laetitia; Sokhna, Cheikh; Gómez-Olivé, F Xavier; Mee, Paul; Tollman, Stephen M; Herbst, Kobus; Mossong, Joël; Chuc, Nguyen T K; Arthur, Samuelina S; Sankoh, Osman A; Byass, Peter

2014-01-01

As the HIV/AIDS pandemic has evolved over recent decades, Africa has been the most affected region, even though a large proportion of HIV/AIDS deaths have not been documented at the individual level. Systematic application of verbal autopsy (VA) methods in defined populations provides an opportunity to assess the mortality burden of the pandemic from individual data. To present standardised comparisons of HIV/AIDS-related mortality at sites across Africa and Asia, including closely related causes of death such as pulmonary tuberculosis (PTB) and pneumonia. Deaths related to HIV/AIDS were extracted from individual demographic and VA data from 22 INDEPTH sites across Africa and Asia. VA data were standardised to WHO 2012 standard causes of death assigned using the InterVA-4 model. Between-site comparisons of mortality rates were standardised using the INDEPTH 2013 standard population. The dataset covered a total of 10,773 deaths attributed to HIV/AIDS, observed over 12,204,043 person-years. HIV/AIDS-related mortality fractions and mortality rates varied widely across Africa and Asia, with highest burdens in eastern and southern Africa, and lowest burdens in Asia. There was evidence of rapidly declining rates at the sites with the heaviest burdens. HIV/AIDS mortality was also strongly related to PTB mortality. On a country basis, there were strong similarities between HIV/AIDS mortality rates at INDEPTH sites and those derived from modelled estimates. Measuring HIV/AIDS-related mortality continues to be a challenging issue, all the more so as anti-retroviral treatment programmes alleviate mortality risks. The congruence between these results and other estimates adds plausibility to both approaches. These data, covering some of the highest mortality observed during the pandemic, will be an important baseline for understanding the future decline of HIV/AIDS.

Ignition and structure of a laminar diffusion flame in a compressible mixing layer with finite rate chemistry

NASA Technical Reports Server (NTRS)

Grosch, C. E.; Jackson, T. L.

1991-01-01

The ignition and structure of a reacting compressible mixing layer is considered using finite rate chemistry lying between two streams of reactants with different freestream speeds and temperatures. Numerical integration of the governing equations show that the structure of the reacting flow can be quite complicated depending on the magnitude of the Zeldovich number. An analysis of both the ignition a diffusion flame regimes is presented using a combination of large Zeldovich number asymptotics and numerics. This allows to analyze the behavior of these regimes as a function of the parameters of the problem.

Age-related apparent diffusion coefficient changes in the normal brain.

PubMed

Watanabe, Memi; Sakai, Osamu; Ozonoff, Al; Kussman, Steven; Jara, Hernán

2013-02-01

To measure the mean diffusional age-related changes of the brain over the full human life span by using diffusion-weighted spin-echo single-shot echo-planar magnetic resonance (MR) imaging and sequential whole-brain apparent diffusion coefficient (ADC) histogram analysis and, secondarily, to build mathematical models of these normal age-related changes throughout human life. After obtaining institutional review board approval, a HIPAA-compliant retrospective search was conducted for brain MR imaging studies performed in 2007 for various clinical indications. Informed consent was waived. The brain data of 414 healthy subjects (189 males and 225 females; mean age, 33.7 years; age range, 2 days to 89.3 years) were obtained with diffusion-weighted spin-echo single-shot echo-planar MR imaging. ADC histograms of the whole brain were generated. ADC peak values, histogram widths, and intracranial volumes were plotted against age, and model parameters were estimated by using nonlinear regression. Four different stages were identified for aging changes in ADC peak values, as characterized by specific mathematical terms: There were age-associated exponential decays for the maturation period and the development period, a constant term for adulthood, and a linear increase for the senescence period. The age dependency of ADC peak value was simulated by using four-term six-coefficient function, including biexponential and linear terms. This model fit the data very closely (R(2) = 0.91). Brain diffusivity as a whole demonstrated age-related changes through four distinct periods of life. These results could contribute to establishing an ADC baseline of the normal brain, covering the full human life span.

Thalamic diffusion differences related to cognitive function in white matter lesions.

PubMed

Fernández-Andújar, Marina; Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Cáceres, Cynthia; Bargalló, Núria; Barrios, Maite; Arenillas, Juan Francisco; Toran, Pere; Alzamora, Maite; Clemente, Imma; Dávalos, Antoni; Mataró, Maria

2014-05-01

Cerebral white matter lesions (WMLs) are related to cognitive deficits, probably due to a disruption of frontal-subcortical circuits. We explored thalamic diffusion differences related to white matter lesions (WMLs) and their association with cognitive function in middle-aged individuals. Ninety-six participants from the Barcelona-AsIA Neuropsychology Study were included. Participants were classified into groups based on low grade and high grade of periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs). Tract-Based Spatial Statistics was used to study thalamic diffusion differences between groups. Mean fractional anisotropy (FA) values in significant areas were calculated for each subject and correlated with cognitive performance. Participants with high-grade PVHs and DWMHs showed lower FA thalamic values compared to those with low-grade PVHs and DWMHs, respectively. Decreased FA thalamic values in high-grade DWMHs, but not high-grade PVH, were related to lower levels of performance in psychomotor speed, verbal fluency, and visuospatial skills. Thalamic diffusion differences are related to lower cognitive function only in participants with high-grade DWMHs. These results support the hypothesis that fronto-subcortical disruption is associated with cognitive function only in DWMHs. Copyright © 2014 Elsevier Inc. All rights reserved.

(Energetics of silicate melts from thermal diffusion studies)

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

Not Available

1989-01-01

Research during the past year has been concentrated in four major areas. We are continuing work initiated during the first two years on modelling thermal diffusion on multicomponent silicate liquids. We have derived appropriate relations for ternary and quaternary systems and reanalyzed experimental thermal diffusion data for the ternary system fayalite-leucite-silica. In our manuscript entitled Thermal Diffusion in Petrology'', to be published in Adv. in Phy. Geochem., we show that these model results independently recover the compositional extent and temperature of liquid immiscibility in this system. Such retrieval provides a rigorous test of our theoretical predictions and simplified treatment ofmore » complex silicate liquids reported in Geochimica Cosmochimica Acta in 1986. The usefulness of our Soret research in providing mixing energies of silicate liquids has been recently confirmed by Ghiorso (1987, Cont. Min. Pet.). This demonstration provides a strategy for incorporating Soret data into the calibration of phase equilibrium-based solution models such as the one developed by Ghiorso. During the past year we also have resumed our studies of thermal diffusion in borosilicate glasses which also exhibit liquid immiscibility. Our objectives in studying these systems are (1) to further test of our multicomponent thermal diffusion model and (2) to provide quantitative constraints on the mixing properties of these glass-forming systems which are important for evaluating their suitability for storage of high-level nuclear waste. 16 refs.« less

Transient liquid phase diffusion bonding of Udimet 720 for Stirling power converter applications

NASA Technical Reports Server (NTRS)

Mittendorf, Donald L.; Baggenstoss, William G.

1992-01-01

Udimet 720 has been selected for use on Stirling power converters for space applications. Because Udimet 720 is generally considered susceptible to strain age cracking if traditional fusion welding is used, other joining methods are being considered. A process for transient liquid phase diffusion bonding of Udimet 720 has been theoretically developed in an effort to eliminate the strain age crack concern. This development has taken into account such variables as final grain size, joint homogenization, joint efficiency related to bonding aid material, bonding aid material application method, and thermal cycle.

IgM, IgG and IgA rheumatoid factors and circulating immune complexes in patients with AIDS and AIDS-related complex with serological abnormalities.

PubMed Central

Procaccia, S; Lazzarin, A; Colucci, A; Gasparini, A; Forcellini, P; Lanzanova, D; Foppa, C U; Novati, R; Zanussi, C

1987-01-01

To investigate some humoral aspects which may reflect the involvement of B lymphocytes in the acquired immunodeficiency syndrome (AIDS), we used an enzyme-linked immunoassay (ELISA) to determine the levels of IgM, IgG and IgA rheumatoid factors (RF) in 16 patients suffering from full-blown AIDS and 32 patients with AIDS-related complex (ARC), in the clinical form of lymphoadenopathy syndrome (LAS), compared with 40 healthy, young heterosexual subjects. Both AIDS and ARC patients showed a greater incidence of high IgM RF levels, with mean values significantly higher than controls, but with no differences between the two pathological groups. IgG RF behaviour was similar in the two patient populations and the healthy subjects. IgA RF were significantly raised in AIDS and ARC. Further information on RF was obtained by determination of the immunoglobulin levels of the respective isotypes in the same patients. Mean IgG levels were above normal in AIDS and ARC patients, but the latter group showed a higher incidence of increased values and higher mean levels. The IgA isotype was significantly increased mainly in AIDS patients. The behaviour of IgM was virtually the same in the three groups studied. A difference between AIDS and ARC patients was established by the detection of circulating immune-complexes (IC) by the C1q-binding and CIC-conglutinin assays. IC were significantly high, by both methods, only in the ARC group, but normal or very low in AIDS. These overall findings suggest once again the impairment of B cell function in AIDS, with prevalent hyperactivation in ARC and exhaustion in full-blown AIDS, and apparent preservation, in the latter group, of the antibody responses which are more closely related to the activity of subsets of T helper cells. PMID:3608224

The role of individual and personality factors in controlling risky behaviours related to AIDS: Proposing a causal model.

PubMed

Rezaei, Mansour; Zakiei, Ali; Reshadat, Soheyla; Ghasemi, Seyed Ramin

2017-02-01

Investigating previous studies show that personality traits have an important role in controlling risky behaviours related to AIDS; therefore, the aim of this study is to investigate the relationship between AIDS health literacy, personality traits and mental health and controlling risky behaviours related to AIDS through self-efficacy. The statistical population includes all the young people in western provinces of Iran, 2015. Data analysis was carried out for a sample of 756 participants (59% female). The results show that except for the socializing trait, all the other variables are related to controlling risky behaviours. In addition, variables of health literacy related to AIDS, mental health, activity, impulsive sensation seeking and hostility have a direct relation to controlling risky behaviours. Also, the predicting behaviours can predict 62% of the variance in controlling risky behaviours related to AIDS. The analysis results show that health literacy has an indirect impact on controlling risky behaviours through self-efficacy. In other words, health literacy related to AIDS leads to controlling risky behaviours when self-efficacy is high for controlling risky behaviours. Based on the results, it is recommended that the role of self-efficacy in controlling risky behaviours be considered as a strategy for preventing AIDS. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Conservative mixing, competitive mixing and their applications

NASA Astrophysics Data System (ADS)

Klimenko, A. Y.

2010-12-01

In many of the models applied to simulations of turbulent transport and turbulent combustion, the mixing between particles is used to reflect the influence of the continuous diffusion terms in the transport equations. Stochastic particles with properties and mixing can be used not only for simulating turbulent combustion, but also for modeling a large spectrum of physical phenomena. Traditional mixing, which is commonly used in the modeling of turbulent reacting flows, is conservative: the total amount of scalar is (or should be) preserved during a mixing event. It is worthwhile, however, to consider a more general mixing that does not possess these conservative properties; hence, our consideration lies beyond traditional mixing. In non-conservative mixing, the particle post-mixing average becomes biased towards one of the particles participating in mixing. The extreme form of non-conservative mixing can be called competitive mixing or competition: after a mixing event, the loser particle simply receives the properties of the winner particle. Particles with non-conservative mixing can be used to emulate various phenomena involving competition. In particular, we investigate cyclic behavior that can be attributed to complex competing systems. We show that the localness and intransitivity of competitive mixing are linked to the cyclic behavior.

Aids to navigation service force mix 2000 project. Volume 3 : analysis of multi-mission requirements and development of planning factors for the replacement buoy tender fleet

DOT National Transportation Integrated Search

1992-06-01

The Aids to Navigation (ATON) Service Force Mix (SFM) 2000 Project is documented in a Project Overview and three separately bound volumes. This is Volume III. The Project Overview describes the purpose, approach, analysis, and results of the ATON SFM...

AIDS-related knowledge and risks and contraceptive practices in Ghana: the early 1990s.

PubMed

Takyi, B K

2000-04-01

HIV/AIDS in Africa is transmitted primarily through heterosexual contact. This mode of disease transmission places sexually active childbearing women at high risk of contracting the disease. In this study, data from the 1993/94 Ghana Demographic Health Survey were used to explore the relationship between AIDS-related knowledge and family planning practices, specifically the use of contraceptives and condoms. While the study finds high levels of AIDS-related knowledge among Ghanaian women, this knowledge is yet to translate into increased condom use. It is suggested that the use of rational choice models in AIDS prevention programs may not be adequate to change people's sexual behaviour, especially in societies where the prevailing cultural practices and norms encourage large families and discourage the use of contraceptives of any type. In such settings, there is the need to find appropriate mechanisms that could help increase the use of all types of contraceptives. As contraceptive use increases, it is likely that the use of condoms for AIDS prevention and also for family planning purpose would increase in sub-Saharan Africa.

Bio-ethical and legal issues in relation to HIV/AIDS: the Uganda experience.

PubMed

Yusuf, N K

1998-01-01

In Uganda, as in many other countries, there is a vacuum regarding an appropriate legal and ethical response to the HIV/AIDS pandemic. Whereas much has been done to address the HIV/AIDS pandemic in a multidisciplinary way, very little has been done regarding legal and ethical issues. Hence, cases of claimants to have cures for AIDS, spiritual healers and sale of fake drugs plus unauthorized vaccine and drug trials are on the increase. The rights and needs of people infected with HIV/AIDS are not adequately addressed. The property rights of those affected by the pandemic continue to be abused. Therefore there is need to mobilize doctors, lawyers and human rights activists who should advocate and address these issues. This paper therefore highlights the critical bio-ethical and legal issues in relation to HIV/AIDS.

Immunophototherapy for the treatment of AIDS and AIDS-related infections

NASA Astrophysics Data System (ADS)

Schlager, Kenneth J.

1992-06-01

Immunophototherapy (IPT) is an experimental method of medical treatment that seeks to provide for the selective destruction of diseased cells and microbes such as human immunodeficiency virus (HIV)-T4 cells and the rapid elimination of their toxic by-products from the human body. Photosensitive monoclonal or polyclonal antibody fragments, which are specific to the diseased cell or microbe, will be used to treat acquired immunodeficiency syndrome (AIDS) and related infections. These antibody fragments are tagged with photosensitive compounds and metal colloids and then intravenously injected into the patient. The tagged antibodies quickly and selectively bind to the diseased cells or microbes in the blood stream and affected organs. These cells or microbes are then selectively destroyed by irradiation of these complexes with light of the proper wavelength. This light activates the photosensitive material which then creates singlet oxygen that destroys the microbe or cell. Toxic products of lysis are quickly discharged from the body by activation of the reticuloendothelial system. IPT has been demonstrated by Biotronics to be very effective in the in vitro selective destruction of specified cell types. In a proposed AIDS-treatment research program, IPT will be first demonstrated in vitro for a set of infected blood samples using commercially-available antibodies labeled with appropriate photosensitizers. Efficacy will be determined by a p24 antigen immunodiagnostic test that will indicate the % inhibition in comparison to controls and samples treated with the drug AZT. Subcontracted animal efficacy studies will use a SCID-hu mouse model and PCR/DNA-RNA for endpoint analysis. Toxicity studies of animal (rat) models will be based on post-treatment investigations of lymph nodes, spleen, liver and other organs.

Sunitinib Malate in Treating HIV-Positive Patients With Cancer Receiving Antiretroviral Therapy

ClinicalTrials.gov

2014-03-14

Accelerated Phase Chronic Myelogenous Leukemia; Acute Myeloid Leukemia With Multilineage Dysplasia Following Myelodysplastic Syndrome; Acute Undifferentiated Leukemia; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Adult Grade III Lymphomatoid Granulomatosis; Adult Langerhans Cell Histiocytosis; Adult Nasal Type Extranodal NK/T-cell Lymphoma; Aggressive NK-cell Leukemia; AIDS-related Diffuse Large Cell Lymphoma; AIDS-related Diffuse Mixed Cell Lymphoma; AIDS-related Diffuse Small Cleaved Cell Lymphoma; AIDS-related Immunoblastic Large Cell Lymphoma; AIDS-related Lymphoblastic Lymphoma; AIDS-related Malignancies; AIDS-related Small Noncleaved Cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; Clear Cell Renal Cell Carcinoma; Cutaneous B-cell Non-Hodgkin Lymphoma; de Novo Myelodysplastic Syndromes; Essential Thrombocythemia; Extramedullary Plasmacytoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Hepatosplenic T-cell Lymphoma; HIV Infection; HIV-associated Hodgkin Lymphoma; Intraocular Lymphoma; Isolated Plasmacytoma of Bone; Light Chain Deposition Disease; Mast Cell Leukemia; Myelodysplastic Syndrome With Isolated Del(5q); Myelodysplastic/Myeloproliferative Neoplasm, Unclassifiable; Myeloid/NK-cell Acute Leukemia; Nodal Marginal Zone B-cell Lymphoma; Noncutaneous Extranodal Lymphoma; Osteolytic Lesions of Multiple Myeloma; Peripheral T-cell Lymphoma; Plasma Cell Neoplasm; Polycythemia Vera; Post

AIDS-related dementia: a case report of rapid cognitive decline.

PubMed

Morgan, M K; Clark, M E; Hartman, W L

1988-11-01

Little is known psychometrically about the pattern of cognitive decline associated with acquired immunodeficiency syndrome (AIDS)-related dementia. Pre- and posttest results are presented to illustrate a case example of rapid cognitive decline. Increased psychometric assessment is recommended with additional examination of inconsistent results, which may be dismissed mistakenly as related to psychiatric symptoms. Implications for clinical practice and the role of the psychologist are discussed.

Venus' superrotation, mixing length theory and eddy diffusion - A parametric study

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Harris, I.; Schatten, K. H.; Stevens-Rayburn, D. R.; Chan, K. L.

1988-01-01

The concept of the Hadley mechanism is adopted to describe the axisymmetric circulation of the Venus atmosphere. It is shown that, for the atmosphere of a slowly rotating planet such as Venus, a form of the nonliner 'closure' (self-consistent solution) of the fluid dynamics system which constrains the magnitude of the eddy diffusion coefficients can be postulated. A nonlinear one-layer spectral model of the zonally symmetric circulation was then used to establish the relationship between the heat source, the meridional circulation, and the eddy diffusion coefficients, yielding large zonal velocities. Computer experiments indicated that proportional changes in the heat source and eddy diffusion coefficients do not significantly change the zonal velocities. It was also found that, for large eddy diffusion coefficients, the meridional velocity is virtually constant; below a threshold in the diffusion rate, the meridional velocity decreases; and, for large eddy diffusion and small heating rates, the zonal velocities decrease with decreasing planetary rotation rates.

Understanding and Improving Ocean Mixing Parameterizations for modeling Climate Change

NASA Astrophysics Data System (ADS)

Howard, A. M.; Fells, J.; Clarke, J.; Cheng, Y.; Canuto, V.; Dubovikov, M. S.

2017-12-01

Climate is vital. Earth is only habitable due to the atmosphere&oceans' distribution of energy. Our Greenhouse Gas emissions shift overall the balance between absorbed and emitted radiation causing Global Warming. How much of these emissions are stored in the ocean vs. entering the atmosphere to cause warming and how the extra heat is distributed depends on atmosphere&ocean dynamics, which we must understand to know risks of both progressive Climate Change and Climate Variability which affect us all in many ways including extreme weather, floods, droughts, sea-level rise and ecosystem disruption. Citizens must be informed to make decisions such as "business as usual" vs. mitigating emissions to avert catastrophe. Simulations of Climate Change provide needed knowledge but in turn need reliable parameterizations of key physical processes, including ocean mixing, which greatly impacts transport&storage of heat and dissolved CO2. The turbulence group at NASA-GISS seeks to use physical theory to improve parameterizations of ocean mixing, including smallscale convective, shear driven, double diffusive, internal wave and tidal driven vertical mixing, as well as mixing by submesoscale eddies, and lateral mixing along isopycnals by mesoscale eddies. Medgar Evers undergraduates aid NASA research while learning climate science and developing computer&math skills. We write our own programs in MATLAB and FORTRAN to visualize and process output of ocean simulations including producing statistics to help judge impacts of different parameterizations on fidelity in reproducing realistic temperatures&salinities, diffusivities and turbulent power. The results can help upgrade the parameterizations. Students are introduced to complex system modeling and gain deeper appreciation of climate science and programming skills, while furthering climate science. We are incorporating climate projects into the Medgar Evers college curriculum. The PI is both a member of the turbulence group at

Population Density and AIDS-Related Stigma in Large-Urban, Small-Urban, and Rural Communities of the Southeastern USA.

PubMed

Kalichman, Seth; Katner, Harold; Banas, Ellen; Kalichman, Moira

2017-07-01

AIDS stigmas delay HIV diagnosis, interfere with health care, and contribute to mental health problems among people living with HIV. While there are few studies of the geographical distribution of AIDS stigma, research suggests that AIDS stigmas are differentially experienced in rural and urban areas. We conducted computerized interviews with 696 men and women living with HIV in 113 different zip code areas that were classified as large-urban, small-urban, and rural areas in a southeast US state with high-HIV prevalence. Analyses conducted at the individual level (N = 696) accounting for clustering at the zip code level showed that internalized AIDS-related stigma (e.g., the sense of being inferior to others because of HIV) was experienced with greater magnitude in less densely populated communities. Multilevel models indicated that after adjusting for potential confounding factors, rural communities reported greater internalized AIDS-related stigma compared to large-urban areas and that small-urban areas indicated greater experiences of enacted stigma (e.g., discrimination) than large-urban areas. The associations between anticipated AIDS-related stigma (e.g., expecting discrimination) and population density at the community-level were not significant. Results suggest that people living in rural and small-urban settings experience greater AIDS-related internalized and enacted stigma than their counterparts living in large-urban centers. Research is needed to determine whether low-density population areas contribute to or are sought out by people who experienced greater AIDS-related stigma. Regardless of causal directions, interventions are needed to address AIDS-related stigma, especially among people in sparsely populated areas with limited resources.

40 CFR 227.29 - Initial mixing.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Initial mixing is defined to be that dispersion or diffusion of liquid, suspended particulate, and solid... adequate to predict initial dispersion and diffusion of the waste, these shall be used, if necessary, in.... (2) When field data on the dispersion and diffusion of a waste of characteristics similar to that...

40 CFR 227.29 - Initial mixing.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Initial mixing is defined to be that dispersion or diffusion of liquid, suspended particulate, and solid... adequate to predict initial dispersion and diffusion of the waste, these shall be used, if necessary, in.... (2) When field data on the dispersion and diffusion of a waste of characteristics similar to that...

40 CFR 227.29 - Initial mixing.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Initial mixing is defined to be that dispersion or diffusion of liquid, suspended particulate, and solid... adequate to predict initial dispersion and diffusion of the waste, these shall be used, if necessary, in.... (2) When field data on the dispersion and diffusion of a waste of characteristics similar to that...

40 CFR 227.29 - Initial mixing.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Initial mixing is defined to be that dispersion or diffusion of liquid, suspended particulate, and solid... adequate to predict initial dispersion and diffusion of the waste, these shall be used, if necessary, in.... (2) When field data on the dispersion and diffusion of a waste of characteristics similar to that...

The mixing mechanism during lithiation of Si negative electrode in Li-ion batteries: an ab initio molecular dynamics study.

PubMed

Johari, Priya; Qi, Yue; Shenoy, Vivek B

2011-12-14

In order to realize Si as a negative electrode material in commercial Li-ion batteries, it is important to understand the mixing mechanism of Li and Si, and stress evolution during lithiation in Si negative electrode of Li-ion batteries. Available experiments mainly provide the diffusivity of Li in Si as an averaged property, neglecting information regarding diffusivity of Si. However, if Si can diffuse as fast as Li, the stress generated during Li diffusion can be reduced. We, therefore, studied the diffusivity of Li as well as Si atoms in the Si-anode of Li-ion battery using an ab initio molecular dynamics-based methodology. The electrochemical insertion of Li into crystalline Si prompts a crystalline-to-amorphous phase transition. We considered this situation and thus examined the diffusion kinetics of Li and Si atoms in both crystalline and amorphous Si. We find that Li diffuses faster in amorphous Si as compared to crystalline Si, while Si remains relatively immobile in both cases and generates stresses during lithiation. To further understand the mixing mechanism and to relate the structure with electrochemical mixing, we analyzed the evolution of the structure during lithiation and studied the mechanism of breaking of Si-Si network by Li. We find that Li atoms break the Si rings and chains and create ephemeral structures such as stars and boomerangs, which eventually transform to Si-Si dumbbells and isolated Si atoms in the LiSi phase. Our results are found to be in agreement with the available experimental data and provide insights into the mixing mechanism of Li and Si in Si negative electrode of Li-ion batteries.

Characteristics of the mixing volume model with the interactions among spatially distributed particles for Lagrangian simulations of turbulent mixing

NASA Astrophysics Data System (ADS)

Watanabe, Tomoaki; Nagata, Koji

2016-11-01

The mixing volume model (MVM), which is a mixing model for molecular diffusion in Lagrangian simulations of turbulent mixing problems, is proposed based on the interactions among spatially distributed particles in a finite volume. The mixing timescale in the MVM is derived by comparison between the model and the subgrid scale scalar variance equation. A-priori test of the MVM is conducted based on the direct numerical simulations of planar jets. The MVM is shown to predict well the mean effects of the molecular diffusion under various conditions. However, a predicted value of the molecular diffusion term is positively correlated to the exact value in the DNS only when the number of the mixing particles is larger than two. Furthermore, the MVM is tested in the hybrid implicit large-eddy-simulation/Lagrangian-particle-simulation (ILES/LPS). The ILES/LPS with the present mixing model predicts well the decay of the scalar variance in planar jets. This work was supported by JSPS KAKENHI Nos. 25289030 and 16K18013. The numerical simulations presented in this manuscript were carried out on the high performance computing system (NEC SX-ACE) in the Japan Agency for Marine-Earth Science and Technology.

Connection between encounter volume and diffusivity in geophysical flows

NASA Astrophysics Data System (ADS)

Rypina, Irina I.; Smith, Stefan G. Llewellyn; Pratt, Larry J.

2018-04-01

Trajectory encounter volume - the volume of fluid that passes close to a reference fluid parcel over some time interval - has been recently introduced as a measure of mixing potential of a flow. Diffusivity is the most commonly used characteristic of turbulent diffusion. We derive the analytical relationship between the encounter volume and diffusivity under the assumption of an isotropic random walk, i.e., diffusive motion, in one and two dimensions. We apply the derived formulas to produce maps of encounter volume and the corresponding diffusivity in the Gulf Stream region of the North Atlantic based on satellite altimetry, and discuss the mixing properties of Gulf Stream rings. Advantages offered by the derived formula for estimating diffusivity from oceanographic data are discussed, as well as applications to other disciplines.

Structure and ionic diffusion of alkaline-earth ions in mixed cation glasses A 2O–2MO–4SiO 2 with molecular dynamics simulations

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

Konstantinou, Konstantinos; Sushko, Petr; Duffy, Dorothy M.

2015-05-15

A series of mixed cation silicate glasses of the composition A2O – 2MO – 4SiO2, with A=Li,Na,K and M=Ca,Sr,Ba has been investigated by means of molecular dynamics simulations in order to understand the effect of the nature of the cations on the mobility of the alkaline-earth ions within the glass network. The size of the alkaline-earth cation was found to affect the inter-atomic distances, the coordination number distributions and the bond angle distributions , whereas the medium-range order was almost unaffected by the type of the cation. All the alkaline-earth cations contribute to lower vibrational frequencies but it is observedmore » that that there is a shift to smaller frequencies and the vibrational density of states distribution gets narrower as the size of the alkaline-earth increases. The results from our modeling for the ionic diffusion of the alkaline-earth cations are in a qualitative agreement with the experimental observations in that there is a distinct correlation between the activation energy for diffusion of alkaline earth-ions and the cation radii ratio. An asymmetrical linear behavior in the diffusion activation energy with increasing size difference is observed. The results can be described on the basis of a theoretical model that relates the diffusion activation energy to the electrostatic interactions of the cations with the oxygens and the elastic deformation of the silicate network.« less

Pediatric mobility aid-related injuries treated in US emergency departments from 1991 to 2008.

PubMed

Barnard, Alison M; Nelson, Nicolas G; Xiang, Huiyun; McKenzie, Lara B

2010-06-01

Although mobility aids such as crutches, walkers, and wheelchairs are typically beneficial, they can be associated with injury. The objective of this study was to describe the incidence, patterns, and trends of pediatric mobility aid-related injuries to children and adolescents who were aged < or = 19 years and treated in US emergency departments between 1991 and 2008. A retrospective analysis was conducted by using data from the National Electronic Injury Surveillance System database for children and adolescents who were aged < or = 19 years. Sample weights were used to calculate national estimates of mobility aid-related injuries on the basis of 2301 actual cases. An estimated 63 309 cases of children and adolescents who were aged < or = 19 years were treated in US emergency departments for mobility aid-related injuries. Approximately 70% of mobility aid- related injuries occurred while patients were using wheelchairs. Children who were aged 2 to 10 years were more likely to sustain injuries while using walkers and wheelchairs, injure their heads, and sustain traumatic brain injuries. Children who were aged 11 to 19 years were more likely to sustain injuries while using crutches, injure their lower extremities, and sustain sprains and strains. Injuries involving wheelchairs were more likely to be traumatic brain injuries and result in hospitalization. Injuries involving crutches were more likely to involve misuse and be triggered by stairs or curbs. Injuries related to crutches, walkers, and wheelchairs have distinct injury patterns, mechanisms of injury, and trigger factors. Injury patterns between younger and older children were different. Additional research is needed to identify effective injury prevention strategies for the pediatric population.

Paramagnetic particles and mixing in micro-scale flows.

PubMed

Calhoun, R; Yadav, A; Phelan, P; Vuppu, A; Garcia, A; Hayes, M

2006-02-01

Mixing in microscale flows with rotating chains of paramagnetic particles can be enhanced by adjusting the ratio of viscous to magnetic forces so that chains dynamically break and reform. Lattice Boltzmann (LB) simulations were used to calculate the interaction between the fluid and suspended paramagnetic particles under the influence of a rotating magnetic field. Fluid velocities obtained from the LB simulations are used to solve the advection diffusion equation for massless tracer particles. At relatively high Mason numbers, small chains result in low edge velocities, and hence mixing is slower than at other Mason numbers. At low Mason numbers, long, stable chains form and produce little mixing toward the center of the chains. A peak in mixing rate is observed when chains break and reform. The uniformity of mixing is greater at higher Mason numbers because more small chains result in a larger number of small mixing areas.

"Diffusion" region of magnetic reconnection: electron orbits and the phase space mixing

NASA Astrophysics Data System (ADS)

Kropotkin, Alexey P.

2018-05-01

The nonlinear dynamics of electrons in the vicinity of magnetic field neutral lines during magnetic reconnection, deep inside the diffusion region where the electron motion is nonadiabatic, has been numerically analyzed. Test particle orbits are examined in that vicinity, for a prescribed planar two-dimensional magnetic field configuration and with a prescribed uniform electric field in the neutral line direction. On electron orbits, a strong particle acceleration occurs due to the reconnection electric field. Local instability of orbits in the neighborhood of the neutral line is pointed out. It combines with finiteness of orbits due to particle trapping by the magnetic field, and this should lead to the effect of mixing in the phase space, and the appearance of dynamical chaos. The latter may presumably be viewed as a mechanism producing finite conductivity in collisionless plasma near the neutral line. That conductivity is necessary to provide violation of the magnetic field frozen-in condition, i.e., for magnetic reconnection to occur in that region.

Quantifying Diapycnal Mixing in an Energetic Ocean

NASA Astrophysics Data System (ADS)

Ivey, Gregory N.; Bluteau, Cynthia E.; Jones, Nicole L.

2018-01-01

Turbulent diapycnal mixing controls global circulation and the distribution of tracers in the ocean. For turbulence in stratified shear flows, we introduce a new turbulent length scale Lρ dependent on χ. We show the flux Richardson number Rif is determined by the dimensionless ratio of three length scales: the Ozmidov scale LO, the Corrsin shear scale LS, and Lρ. This new model predicts that Rif varies from 0 to 0.5, which we test primarily against energetic field observations collected in 100 m of water on the Australian North West Shelf (NWS), in addition to laboratory observations. The field observations consisted of turbulence microstructure vertical profiles taken near moored temperature and velocity turbulence time series. Irrespective of the value of the gradient Richardson number Ri, both instruments yielded a median Rif=0.17, while the observed Rif ranged from 0.01 to 0.50, in agreement with the predicted range of Rif. Using a Prandtl mixing length model, we show that diapycnal mixing Kρ can be predicted from Lρ and the background vertical shear S. Using field and laboratory observations, we show that Lρ=0.3LE where LE is the Ellison length scale. The diapycnal diffusivity can thus be calculated from Kρ=0.09LES2. This prediction agrees very well with the diapycnal mixing estimates obtained from our moored turbulence instruments for observed diffusivities as large as 10-1 m2s-1. Moorings with relatively low sampling rates can thus provide long time series estimates of diapycnal mixing rates, significantly increasing the number of diapycnal mixing estimates in the ocean.

Radial mixing in turbomachines

NASA Astrophysics Data System (ADS)

Segaert, P.; Hirsch, Ch.; Deruyck, J.

1991-03-01

A method for computing the effects of radial mixing in a turbomachinery blade row has been developed. The method fits in the framework of a quasi-3D flow computation and hence is applied in a corrective fashion to through flow distributions. The method takes into account both secondary flows and turbulent diffusion as possible sources of mixing. Secondary flow velocities determine the magnitude of the convection terms in the energy redistribution equation while a turbulent diffusion coefficient determines the magnitude of the diffusion terms. Secondary flows are computed by solving a Poisson equation for a secondary streamfunction on a transversal S3-plane, whereby the right-hand side axial vorticity is composed of different contributions, each associated to a particular flow region: inviscid core flow, end-wall boundary layers, profile boundary layers and wakes. The turbulent mixing coefficient is estimated by a semi-empirical correlation. Secondary flow theory is applied to the VUB cascade testcase and comparisons are made between the computational results and the extensive experimental data available for this testcase. This comparison shows that the secondary flow computations yield reliable predictions of the secondary flow pattern, both qualitatively and quantitatively, taking into account the limitations of the model. However, the computations show that use of a uniform mixing coefficient has to be replaced by a more sophisticated approach.

Latinos and HIV/AIDS: Examining Factors Related to Disparity and Identifying Opportunities for Psychosocial Intervention Research

PubMed Central

Hendriksen, Ellen Setsuko; Collins, Erin Marie; Durán, Ron E.; Safren, Steven A.

2013-01-01

Latinos maintain an AIDS case rate more than 3 times higher than whites, a greater rate of progression to AIDS, and a higher rate of HIV/AIDS-related deaths. Three broad areas are reviewed related to these disparities: (1) relevant demographic, socioeconomic, and socio-cultural factors among Latinos; (2) drug abuse and mental health problems in Latinos relevant to HIV/AIDS outcomes; and (3) opportunities for psychosocial intervention. Latinos living with HIV are a rapidly growing group, are more severely impacted by HIV than whites, and confront unique challenges in coping with HIV/AIDS. A body of research suggests that depression, substance abuse, treatment adherence, health literacy, and access to healthcare may be fruitful targets for intervention research in this population. Though limited, the current literature suggests that psychosocial interventions that target these factors could help reduce HIV/AIDS disparities between Latinos and whites and could have important public health value. PMID:18498050

Isotope fractionation by multicomponent diffusion (Invited)

NASA Astrophysics Data System (ADS)

Watkins, J. M.; Liang, Y.; Richter, F. M.; Ryerson, F. J.; DePaolo, D. J.

2013-12-01

the rate of CaO diffusion; in A-B, the total variation is 2.5‰ whereas in D-E it is only 1.3‰. The diffusion of isotopes in a multicomponent system is modeled using a new expression for the isotope-specific diffusive flux that includes self diffusion terms in addition to the multicomponent chemical diffusion matrix. Kinetic theory predicts a mass dependence on isotopic mobility, i.e., self diffusivity, but it is unknown whether or how the mass dependence on self diffusivity translates into a mass dependence on chemical diffusion coefficients. The new experimental results allow us to assess several empirical expressions relating the self diffusivity and its mass dependence to the elements of the diffusion matrix and their mass dependence. Several plausible theoretical treatments can fit the data equally well. We are currently at the stage where experiments are guiding the theoretical treatment of the isotope fractionation by diffusion problem, underscoring the importance of experiments for aiding interpretations of isotopic variations in nature.

Cross-national diffusion of mental health policy

PubMed Central

Shen, Gordon C

2014-01-01

Background: Following the tenets of world polity and innovation diffusion theories, I focus on the coercive and mimetic forces that influence the diffusion of mental health policy across nations. International organizations’ mandates influence government behavior. Dependency on external resources, namely foreign aid, also affects governments’ formulation of national policy. And finally, mounting adoption in a region alters the risk, benefits, and information associated with a given policy. Methods: I use post-war, discrete time data spanning 1950 to 2011 and describing 193 nations’ mental health systems to test these diffusion mechanisms. Results: I find that the adoption of mental health policy is highly clustered temporally and spatially. Results provide support that membership in the World Health Organization (WHO), interdependence with neighbors and peers in regional blocs, national income status, and migrant sub-population are responsible for isomorphism. Aid, however, is an insufficient determinant of mental health policy adoption. Conclusion: This study examines the extent to which mental, neurological, and substance use disorder are addressed in national and international contexts through the lens of policy diffusion theory. It also adds to policy dialogues about non-communicable diseases as nascent items on the global health agenda. PMID:25337601

Kaposi's sarcoma-associated herpesvirus-like DNA sequences in AIDS-related body-cavity-based lymphomas.

PubMed

Cesarman, E; Chang, Y; Moore, P S; Said, J W; Knowles, D M

1995-05-04

DNA fragments that appeared to belong to an unidentified human herpesvirus were recently found in more than 90 percent of Kaposi's sarcoma lesions associated with the acquired immunodeficiency syndrome (AIDS). These fragments were also found in 6 of 39 tissue samples without Kaposi's sarcoma, including 3 malignant lymphomas, from patients with AIDS, but not in samples from patients without AIDS. We examined the DNA of 193 lymphomas from 42 patients with AIDS and 151 patients who did not have AIDS. We searched the DNA for sequences of Kaposi's sarcoma-associated herpesvirus (KSHV) by Southern blot hybridization, the polymerase chain reaction (PCR), or both. The PCR products in the positive samples were sequences and compared with the KSHV sequences in Kaposi's sarcoma tissues from patients with AIDS. KSHV sequences were identified in eight lymphomas in patients infected with the human immunodeficiency virus. All eight, and only these eight, were body-cavity-based lymphomas--that is, they were characterized by pleural, pericardial, or peritoneal lymphomatous effusions. All eight lymphomas also contained the Epstein-Barr viral genome. KSHV sequences were not found in the other 185 lymphomas. KSHV sequences were 40 to 80 times more abundant in the body-cavity-based lymphomas than in the Kaposi's sarcoma lesions. A high degree of conservation of KSHV sequences in Kaposi's sarcoma and in the eight lymphomas suggests the presence of the same agent in both lesions. The recently discovered KSHV DNA sequences occur in an unusual subgroup of AIDS-related B-cell lymphomas, but not in any other lymphoid neoplasm studied thus far. Our finding strongly suggests that a novel herpesvirus has a pathogenic role in AIDS-related body-cavity-based lymphomas.

Acute white matter changes following sport-related concussion: A serial diffusion tensor and diffusion kurtosis tensor imaging study.

PubMed

Lancaster, Melissa A; Olson, Daniel V; McCrea, Michael A; Nelson, Lindsay D; LaRoche, Ashley A; Muftuler, L Tugan

2016-11-01

Recent neuroimaging studies have suggested that following sport-related concussion (SRC) physiological brain alterations may persist after an athlete has shown full symptom recovery. Diffusion MRI is a versatile technique to study white matter injury following SRC, yet serial follow-up studies in the very acute stages following SRC utilizing a comprehensive set of diffusion metrics are lacking. The aim of the current study was to characterize white matter changes within 24 hours of concussion in a group of high school and collegiate athletes, using Diffusion Tensor and Diffusion Kurtosis Tensor metrics. Participants were reassessed a week later. At 24 hours post-injury, the concussed group reported significantly more concussion symptoms than a well-matched control group and demonstrated poorer performance on a cognitive screening measure, yet these differences were nonsignificant at the 8-day follow-up. Similarly, within 24-hours after injury, the concussed group exhibited a widespread decrease in mean diffusivity, increased axial kurtosis and, to a lesser extent, decreased axial and radial diffusivities compared with control subjects. At 8 days post injury, the differences in these diffusion metrics were even more widespread in the injured athletes, despite improvement of symptoms and cognitive performance. These MRI findings suggest that the athletes might not have reached full physiological recovery a week after the injury. These findings have significant implications for the management of SRC because allowing an athlete to return to play before the brain has fully recovered from injury may have negative consequences. Hum Brain Mapp 37:3821-3834, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The political context of AIDS-related stigma and knowledge in a South African township community

PubMed Central

Forsyth, Brian; Vandormael, Alain; Kershaw, Trace; Grobbelaar, Janis

2014-01-01

The purpose of this study was to examine the presentation of AIDS-related stigma and knowledge within the political context of the South African government’s response to the AIDS epidemic. It was during the 2000 - 2004 period that key government officials publicly challenged the orthodox views of HIV/AIDS, with the South African president, Thabo Mbeki, actively positing the primary role of poverty and other socio-economic stressors in the progression of the AIDS epidemic. This discursive position had real-time effects for AIDS policy-making and ultimately delayed the implementation of a national antiretroviral (ARV) rollout programme. Consequently this position was criticised by commentators in the media and elsewhere for contributing to an already widespread climate of AIDS stigmatisation and misinformation. To shed more light on these claims we conducted a survey in 2005 in Atteridgeville, a South African township, and compared results with those of a similar survey conducted shortly after ARV medications became available in 2004. Results indicated a reduction in AIDS stigma levels across the 1-year period, and that those participants who endorsed contentious political views (such as those expressed by key government officials) were more likely to have a higher level of AIDS-related stigma than those who disagreed. Nevertheless, this study cautions against drawing a causal relationship between the South African government’s position and AIDS-stigmatising attitudes, and suggests that further political and social factors be accounted for in an attempt to gain a fuller understanding of this seemingly complex relationship. PMID:18709210

Megestrol acetate in patients with AIDS-related cachexia.

PubMed

Von Roenn, J H; Armstrong, D; Kotler, D P; Cohn, D L; Klimas, N G; Tchekmedyian, N S; Cone, L; Brennan, P J; Weitzman, S A

1994-09-15

To compare the effects of oral suspensions of megestrol acetate, 800 mg/d, and placebo on body weight in patients with acquired immunodeficiency syndrome (AIDS)-related weight loss. Randomized, double-blind, placebo-controlled trial. Outpatient community and university patient care setting. Consecutive patients with AIDS who had substantial weight loss and anorexia were enrolled. Of 271 patients, 270 and 195 were evaluable for safety and efficacy, respectively. Patients were randomly assigned to receive placebo or megestrol acetate (100 mg, 400 mg, or 800 mg) daily for 12 weeks. The primary efficacy criterion was weight gain. Patients were evaluated at 4-week intervals for changes in weight and body composition, caloric intake, sense of well-being, toxic effects, and appetite. For evaluable patients receiving 800 mg of megestrol acetate per day, 64.2% gained 2.27 kg (5 pounds) or more compared with 21.4% of patients receiving placebo (P < 0.001). An intent-to-treat analysis showed significant differences (P = 0.002) between those receiving placebo and those receiving 800 mg of megestrol acetate for the number of patients who gained 2.27 kg (5 pounds) or more (8 of 32 [25%] compared with 38 of 61 [62.3%], respectively). Compared with patients receiving placebo at the time of maximum weight change, evaluable patients receiving megestrol acetate, 800 mg/d, reported improvement in overall well-being and had an increase in mean weight gain (-0.725 compared with 3.54 kg [-1.6 compared with +7.8 pounds]; P < 0.001), lean body mass (-0.772 compared with +1.14 kg [-1.7 compared with +2.5 pounds]; P < 0.001), appetite grade (P < 0.001), and caloric intake (-107 compared with +645.6 calories/d; P = 0.001). In patients with AIDS-related weight loss, megestrol acetate can stimulate appetite, food intake, and statistically significant weight gain that is associated with a patient-reported improvement in an overall sense of well-being.

Translational Research in NeuroAIDS: A Neuroimmune Pharmacology-Related Course

PubMed Central

Brown, Amanda; Shiramizu, Bruce; Nath, Avindra; Wojna, Valerie

2010-01-01

Neuroimmune pharmacology (NIP) can be considered a multidisciplinary science where areas of neuroscience, immunology, and pharmacology intersect in neurological disorders. The R25 training program titled “Translational Research in NeuroAIDS and Mental Health (TR-NAMH): An innovative mentoring program to promote diversity in NeuroAIDS Research (R25 MH080661)” at the Johns Hopkins University is a web-based interactive course with the goal to improve the capacity of high quality research by developing mentoring programs for (1) doctoral and postdoctoral candidates and junior faculty from racial and ethnic minorities and (2) non-minority individuals at the same levels, whose research focuses on NeuroAIDS disparity issues such as HIV-associated neurocognitive disorders (HAND). This web-based interactive course overcomes the limitations of traditional education such as access to expert faculty and financial burden of scientists from racial and ethnic minority groups in the field of NeuroAIDS research and NIP and identifies rich nurturing environments for investigators to support their careers. The TR-NAMH program identifies a cadre of talented students and investigators eager to commit to innovative educational and training sessions in NeuroAIDS and NIP. The interplay between NIP changes precipitated by HIV infection in the brain makes the study of HAND an outstanding way to integrate important concepts from these two fields. The course includes activities besides those related to didactic learning such as research training and long-term mentoring; hence, the newly learned topics in NIP are continually reinforced and implemented in real-time experiences. We describe how NIP is integrated in the TR-NAMH program in the context of HAND. PMID:20496178

Translational research in NeuroAIDS: a neuroimmune pharmacology-related course.

PubMed

Brown, Amanda; Shiramizu, Bruce; Nath, Avindra; Wojna, Valerie

2011-03-01

Neuroimmune pharmacology (NIP) can be considered a multidisciplinary science where areas of neuroscience, immunology, and pharmacology intersect in neurological disorders. The R25 training program titled "Translational Research in NeuroAIDS and Mental Health (TR-NAMH): An innovative mentoring program to promote diversity in NeuroAIDS Research (R25 MH080661)" at the Johns Hopkins University is a web-based interactive course with the goal to improve the capacity of high quality research by developing mentoring programs for (1) doctoral and postdoctoral candidates and junior faculty from racial and ethnic minorities and (2) non-minority individuals at the same levels, whose research focuses on NeuroAIDS disparity issues such as HIV-associated neurocognitive disorders (HAND). This web-based interactive course overcomes the limitations of traditional education such as access to expert faculty and financial burden of scientists from racial and ethnic minority groups in the field of NeuroAIDS research and NIP and identifies rich nurturing environments for investigators to support their careers. The TR-NAMH program identifies a cadre of talented students and investigators eager to commit to innovative educational and training sessions in NeuroAIDS and NIP. The interplay between NIP changes precipitated by HIV infection in the brain makes the study of HAND an outstanding way to integrate important concepts from these two fields. The course includes activities besides those related to didactic learning such as research training and long-term mentoring; hence, the newly learned topics in NIP are continually reinforced and implemented in real-time experiences. We describe how NIP is integrated in the TR-NAMH program in the context of HAND.

Expandable mixing section gravel and cobble eductor

DOEpatents

Miller, Arthur L.; Krawza, Kenneth I.

1997-01-01

In a hydraulically powered pump for excavating and transporting slurries in hich it is immersed, the improvement of a gravel and cobble eductor including an expandable mixing section, comprising: a primary flow conduit that terminates in a nozzle that creates a water jet internal to a tubular mixing section of the pump when water pressure is applied from a primary supply flow; a tubular mixing section having a center line in alignment with the nozzle that creates a water jet; a mixing section/exit diffuser column that envelopes the flexible liner; and a secondary inlet conduit that forms an opening at a bas portion of the column and adjacent to the nozzle and water jet to receive water saturated gravel as a secondary flow that mixes with the primary flow inside of the mixing section to form a combined total flow that exits the mixing section and decelerates in the exit diffuser.

Edge Probability and Pixel Relativity-Based Speckle Reducing Anisotropic Diffusion.

PubMed

Mishra, Deepak; Chaudhury, Santanu; Sarkar, Mukul; Soin, Arvinder Singh; Sharma, Vivek

2018-02-01

Anisotropic diffusion filters are one of the best choices for speckle reduction in the ultrasound images. These filters control the diffusion flux flow using local image statistics and provide the desired speckle suppression. However, inefficient use of edge characteristics results in either oversmooth image or an image containing misinterpreted spurious edges. As a result, the diagnostic quality of the images becomes a concern. To alleviate such problems, a novel anisotropic diffusion-based speckle reducing filter is proposed in this paper. A probability density function of the edges along with pixel relativity information is used to control the diffusion flux flow. The probability density function helps in removing the spurious edges and the pixel relativity reduces the oversmoothing effects. Furthermore, the filtering is performed in superpixel domain to reduce the execution time, wherein a minimum of 15% of the total number of image pixels can be used. For performance evaluation, 31 frames of three synthetic images and 40 real ultrasound images are used. In most of the experiments, the proposed filter shows a better performance as compared to the state-of-the-art filters in terms of the speckle region's signal-to-noise ratio and mean square error. It also shows a comparative performance for figure of merit and structural similarity measure index. Furthermore, in the subjective evaluation, performed by the expert radiologists, the proposed filter's outputs are preferred for the improved contrast and sharpness of the object boundaries. Hence, the proposed filtering framework is suitable to reduce the unwanted speckle and improve the quality of the ultrasound images.

Load Diffusion in Composite Structures

NASA Technical Reports Server (NTRS)

Horgan, Cornelius O.; Simmonds, J. G.

2000-01-01

This research has been concerned with load diffusion in composite structures. Fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses. The decay behavior of stresses and other field quantities provides a significant aid towards this process. The results are also amendable to parameter study with a large parameter space and should be useful in structural tailoring studies.

Implementation of a diffusion convection surface evolution model in WallDYN

NASA Astrophysics Data System (ADS)

Schmid, K.

2013-07-01

In thermonuclear fusion experiments with multiple plasma facing materials the formation of mixed materials is inevitable. The formation of these mixed material layers is a dynamic process driven the tight interaction between transport in the plasma scrape off layer and erosion/(re-) deposition at the surface. To track this global material erosion/deposition balance and the resulting formation of mixed material layers the WallDYN code has been developed which couples surface processes and plasma transport. The current surface model in WallDYN cannot fully handle the growth of layers nor does it include diffusion. However at elevated temperatures diffusion is a key process in the formation of mixed materials. To remedy this shortcoming a new surface model has been developed which, for the first time, describes both layer growth/recession and diffusion in a single continuous diffusion/convection equation. The paper will detail the derivation of the new surface model and compare it to TRIDYN calculations.

Transformation of anesthesia for ambulatory orthopedic surgery: A mixed-methods study of a diffusion of innovation in healthcare.

PubMed

Leggott, Kyle T; Martin, Matthew; Sklar, David; Helitzer, Deborah; Rosett, Randy; Crandall, Cameron; Vagh, Firoz; Mercer, Deana

2016-09-01

To provide insight into how an innovation in healthcare is implemented and diffused, we studied the transition from routine use of general anesthesia to peripheral nerve blocks (PNBs) for ambulatory orthopedic extremity surgery. Rogers' diffusion of innovations (DOI) theory was used as our theoretical framework. We identified themes that would be helpful for others attempting to diffuse innovations into healthcare settings. A mixed quantitative and qualitative methodology was used. We retrospectively reviewed operative and anesthesia records of patients who underwent ambulatory repair of distal radius fractures or arthroscopic knee meniscus procedures from 1998 to 2012 to identify whether general anesthetics or PNBs were used and the time course of the innovation. We interviewed orthopedic surgeons, anesthesiologists, and a nursing administrator working in the ambulatory surgery unit during the innovation to identify key themes associated with the adoption of PNBs. From 2003 to 2012, use of PNBs increased from less than 10% to 70% of cases studied. The adoption timeframe followed an S-shaped curve. Key themes included improved safety, quality, efficiency, physician leadership and trust, organizational structure, and technological change. The innovation involved an optional decision-making process and took root in a satellite facility and generally fit with Rogers DOI theory. The adoption and diffusion of PNBs provides a useful model for understanding innovations with optional decision-making in healthcare. Critical elements in our case were the characteristics of the innovation, which facilitated the decision-making process, and the positioning of the innovation in a peripheral structure away from core clinical facilities. Copyright © 2016 Elsevier Inc. All rights reserved.

Parental Language Mixing: Its Measurement and the Relation of Mixed Input to Young Bilingual Children's Vocabulary Size

ERIC Educational Resources Information Center

Byers-Heinlein, Krista

2013-01-01

Is parental language mixing related to vocabulary acquisition in bilingual infants and children? Bilingual parents (who spoke English and another language; n = 181) completed the Language Mixing Scale questionnaire, a new self-report measure that assesses how frequently parents use words from two different languages in the same sentence, such as…

Normal versus anomalous self-diffusion in two-dimensional fluids: memory function approach and generalized asymptotic Einstein relation.

PubMed

Shin, Hyun Kyung; Choi, Bongsik; Talkner, Peter; Lee, Eok Kyun

2014-12-07

Based on the generalized Langevin equation for the momentum of a Brownian particle a generalized asymptotic Einstein relation is derived. It agrees with the well-known Einstein relation in the case of normal diffusion but continues to hold for sub- and super-diffusive spreading of the Brownian particle's mean square displacement. The generalized asymptotic Einstein relation is used to analyze data obtained from molecular dynamics simulations of a two-dimensional soft disk fluid. We mainly concentrated on medium densities for which we found super-diffusive behavior of a tagged fluid particle. At higher densities a range of normal diffusion can be identified. The motion presumably changes to sub-diffusion for even higher densities.

Normal versus anomalous self-diffusion in two-dimensional fluids: Memory function approach and generalized asymptotic Einstein relation

NASA Astrophysics Data System (ADS)

Shin, Hyun Kyung; Choi, Bongsik; Talkner, Peter; Lee, Eok Kyun

2014-12-01

Based on the generalized Langevin equation for the momentum of a Brownian particle a generalized asymptotic Einstein relation is derived. It agrees with the well-known Einstein relation in the case of normal diffusion but continues to hold for sub- and super-diffusive spreading of the Brownian particle's mean square displacement. The generalized asymptotic Einstein relation is used to analyze data obtained from molecular dynamics simulations of a two-dimensional soft disk fluid. We mainly concentrated on medium densities for which we found super-diffusive behavior of a tagged fluid particle. At higher densities a range of normal diffusion can be identified. The motion presumably changes to sub-diffusion for even higher densities.

Solution processable broadband transparent mixed metal oxide nanofilm optical coatings via substrate diffusion doping.

PubMed

Glynn, Colm; Aureau, Damien; Collins, Gillian; O'Hanlon, Sally; Etcheberry, Arnaud; O'Dwyer, Colm

2015-12-21

Devices composed of transparent materials, particularly those utilizing metal oxides, are of significant interest due to increased demand from industry for higher fidelity transparent thin film transistors, photovoltaics and a myriad of other optoelectronic devices and optics that require more cost-effective and simplified processing techniques for functional oxides and coatings. Here, we report a facile solution processed technique for the formation of a transparent thin film through an inter-diffusion process involving substrate dopant species at a range of low annealing temperatures compatible with processing conditions required by many state-of-the-art devices. The inter-diffusion process facilitates the movement of Si, Na and O species from the substrate into the as-deposited vanadium oxide thin film forming a composite fully transparent V0.0352O0.547Si0.4078Na0.01. Thin film X-ray diffraction and Raman scattering spectroscopy show the crystalline component of the structure to be α-NaVO3 within a glassy matrix. This optical coating exhibits high broadband transparency, exceeding 90-97% absolute transmission across the UV-to-NIR spectral range, while having low roughness and free of surface defects and pinholes. The production of transparent films for advanced optoelectronic devices, optical coatings, and low- or high-k oxides is important for planar or complex shaped optics or surfaces. It provides opportunities for doping metal oxides to ternary, quaternary or other mixed metal oxides on glass, encapsulants or other substrates that facilitate diffusional movement of dopant species.

The development of a decision aid for tinnitus.

PubMed

Pryce, Helen; Durand, Marie-Anne; Hall, Amanda; Shaw, Rachel; Culhane, Beth-Anne; Swift, Sarah; Straus, Jean; Marks, Elizabeth; Ward, Melanie; Chilvers, Katie

2018-05-09

To develop a decision aid for tinnitus care that would meet international consensus for decision aid quality. A mixed methods design that included qualitative in-depth interviews, literature review, focus groups, user testing and readability checking. Patients and clinicians who have clinical experience of tinnitus. A decision aid for tinnitus care was developed. This incorporates key evidence of efficacy for the most frequently used tinnitus care options, together with information derived from patient priorities when deciding which choice to make. The decision aid has potential to enable shared decision making between clinicians and patients in audiology. The decision aid meets consensus standards.

Expression of activation-induced cytidine deaminase is associated with a poor prognosis of diffuse large B cell lymphoma patients treated with CHOP-based chemotherapy.

PubMed

Kawamura, Kiyoko; Wada, Akihiko; Wang, Ji-Yang; Li, Quanhai; Ishii, Akihiro; Tsujimura, Hideki; Takagi, Toshiyuki; Itami, Makiko; Tada, Yuji; Tatsumi, Koichiro; Shimada, Hideaki; Hiroshima, Kenzo; Tagawa, Masatoshi

2016-01-01

Activation-induced cytidine deaminase (AID) is involved in somatic hypermutation and class switch recombination processes in the antibody formation. The AID activity induces gene mutations and could be associated with transformation processes of B cells. Nevertheless, the relation between AID expression and the prognosis of B cell lymphoma patients remains uncharacterized. We examined expression levels of the AID gene in 89 lymph node specimens from lymphoma and non-lymphoma patients with Northern blot analysis and investigated an association with their survival. The AID gene was preferentially expressed in B cell lymphoma in particular in diffuse large B cell lymphoma and follicular lymphoma. We confirmed AID protein expression in the mRNA-positive but not in the negative specimens with Western blot analysis and immunohistochemical staining. Survival of the patients treated with cyclophosphamide-/doxorubicin-/vincristine-/prednisone-based chemotherapy demonstrated that the prognosis of diffuse large B cell patients was unfavorable in the mRNA-positive group compared with the negative group, and that AID expression levels were correlated with the poor prognosis. In contrast, AID expression was not linked with the prognosis of follicular lymphoma patients. AID expression is a predictive marker for an unfavorable outcome in DLBCL patients treated with the chemotherapy.

The political context of AIDS-related stigma and knowledge in a South African township community.

PubMed

Forsyth, Brian; Vandormael, Alain; Kershaw, Trace; Grobbelaar, Janis

2008-07-01

The purpose of this study was to examine the presentation of AIDS-related stigma and knowledge within the political context of the South African government's response to the AIDS epidemic. It was during the 2000 - 2004 period that key government officials publicly challenged the orthodox views of HIV/AIDS, with the South African president, Thabo Mbeki, actively positing the primary role of poverty and other socio-economic stressors in the progression of the AIDS epidemic. This discursive position had real-time effects for AIDS policy-making and ultimately delayed the implementation of a national antiretroviral (ARV) rollout programme. Consequently this position was criticised by commentators in the media and elsewhere for contributing to an already widespread climate of AIDS stigmatization and misinformation. To shed more light on these claims we conducted a survey in 2005 in Atteridgeville, a South African township, and compared results with those of a similar survey conducted shortly after ARV medications became available in 2004. Results indicated a reduction in AIDS stigma levels across the 1-year period, and that those participants who endorsed contentious political views (such as those expressed by key government officials) were more likely to have a higher level of AIDS-related stigma than those who disagreed. Nevertheless, this study cautions against drawing a causal relationship between the South African government's position and IDS-stigmatizing attitudes, and suggests that further political and social factors be accounted for in an attempt to gain a fuller understanding of this seemingly complex relationship.

A social epidemiological study on HIV/AIDS in a village of Henan Province, China.

PubMed

Yan, Jin; Xiao, Shuiyuan; Zhou, Liang; Tang, Yong; Xu, Guangming; Luo, Dan; Yi, Qifeng

2013-01-01

The HIV/AIDS epidemic caused by commercial blood donation in rural Henan Province of China in the early- to mid-1990s is the largest known cohort in the world related to blood donation but is not fully described. The objectives of this study were to describe the epidemic, epidemiology, and social epidemiology of commercial blood donation and HIV/AIDS. Both qualitative and quantitative mixed methods were used. A village was randomly selected from the 38 key HIV/AIDS pandemic villages in Henan Province. "Demographic Data Form" was applied to collect demographic information of each resident. Focus groups were held for the managers, some residents, members of "HIV/AIDS Work-Team" (organized by the Henan Provincial Government) in the village. Every village physician, people living with HIV/AIDS (PLWHA), school header, and other stakeholders were interviewed individually. The social epidemiology of HIV/AIDS was analyzed under three perspectives of the framework: individual, social, and structural perspectives. In this village, there were 2335 residents, 484 (20.3%) were former donors, 107 (4.6%) were PLWHA, and 96.3% of PLWHA were infected through commercial blood donation. Individually, low education and plasma donation were the risky factors of HIV/AIDS infection. Socially, the epidemic was geography-, kinship-, and conformity-related. Structurally, the related macrostructure factor was policy endorsement of national blood products. The microstructure factors were poverty and value belief on male child in passing down generations. It is concluded that commercial blood donation and HIV/AIDS epidemic in the village are symbiotically related. The epidemic is temporary and socially determined.

Mixing and Formation of Layers by Internal Wave Forcing

NASA Astrophysics Data System (ADS)

Dossmann, Yvan; Pollet, Florence; Odier, Philippe; Dauxois, Thierry

2017-12-01

The energy pathways from propagating internal waves to the scales of irreversible mixing in the ocean are not fully described. In the ocean interior, the triadic resonant instability is an intrinsic destabilization process that may enhance the energy cascade away from topographies. The present study focuses on the integrated impact of mixing processes induced by a propagative normal mode-1 over long-term experiments in an idealized setup. The internal wave dynamics and the evolution of the density profile are followed using the light attenuation technique. Diagnostics of the turbulent diffusivity KT and background potential energy BPE are provided. Mixing effects result in a partially mixed layer colocated with the region of maximum shear induced by the forcing normal mode. The maximum measured turbulent diffusivity is 250 times larger than the molecular value, showing that diapycnal mixing is largely enhanced by small-scale turbulent processes. Intermittency and reversible energy transfers are discussed to bridge the gap between the present diagnostic and the larger values measured in Dossmann et al. (). The mixing efficiency η is assessed by relating the BPE growth to the linearized KE input. One finds a value of Γ=12-19%, larger than the mixing efficiency in the case of breaking interfacial wave. After several hours of forcing, the development of staircases in the density profile is observed. This mechanism has been previously observed in experiments with weak homogeneous turbulence and explained by Phillips (1972) argument. The present experiments suggest that internal wave forcing could also induce the formation of density interfaces in the ocean.

Keeping the Spirit of Community Partnerships Alive in the Scale Up of HIV/AIDS Prevention: Critical Reflections on the Roll Out of DEBI (Diffusion of Effective Behavioral Interventions)

PubMed Central

Pinto, Rogério M.; Hunter, Joyce; Rapkin, Bruce; Remien, Robert H.

2009-01-01

DEBI, or the Diffusion of Effective Behavioral Interventions is the largest centralized effort to diffuse evidence-based prevention science to fight HIV/AIDS in the United States. DEBI seeks to ensure that the most effective science-based prevention interventions are widely implemented across the country in community-based organizations. Thus, this is a particularly timely juncture in which to critically reflect on the extent to which known principles of community collaboration have guided key processes associated with the DEBI rollout. We review the available evidence on how the dissemination of packaged interventions is necessary but not sufficient for ensuring the success of technology transfer. We consider additional principles that are vital for successful technology transfer, which were not central considerations in the rollout of the DEBI initiative. These issues are: (1) community perceptions of a top-down mode of dissemination; (2) the extent to which local innovations are being embraced, bolstered, or eliminated; and (3) contextual and methodological considerations that shape community preparedness. Consideration of these additional factors is necessary in order to effectively document, manage, and advance the science of dissemination and technology transfer in centralized prevention efforts within and outside of HIV/AIDS. PMID:18612809

Anatomy of particle diffusion

NASA Astrophysics Data System (ADS)

Bringuier, E.

2009-11-01

The paper analyses particle diffusion from a thermodynamic standpoint. The main goal of the paper is to highlight the conceptual connection between particle diffusion, which belongs to non-equilibrium statistical physics, and mechanics, which deals with particle motion, at the level of third-year university courses. We start out from the fact that, near equilibrium, particle transport should occur down the gradient of the chemical potential. This yields Fick's law with two additional advantages. First, splitting the chemical potential into 'mechanical' and 'chemical' contributions shows how transport and mechanics are linked through the diffusivity-mobility relationship. Second, splitting the chemical potential into entropic and energetic contributions discloses the respective roles of entropy maximization and energy minimization in driving diffusion. The paper addresses first unary diffusion, where there is only one mobile species in an immobile medium, and next turns to binary diffusion, where two species are mobile with respect to each other in a fluid medium. The interrelationship between unary and binary diffusivities is brought out and it is shown how binary diffusion reduces to unary diffusion in the limit of high dilution of one species amidst the other one. Self- and mutual diffusion are considered and contrasted within the thermodynamic framework; self-diffusion is a time-dependent manifestation of the Gibbs paradox of mixing.

Relative distance between tracers as a measure of diffusivity within moving aggregates

NASA Astrophysics Data System (ADS)

Pönisch, Wolfram; Zaburdaev, Vasily

2018-02-01

Tracking of particles, be it a passive tracer or an actively moving bacterium in the growing bacterial colony, is a powerful technique to probe the physical properties of the environment of the particles. One of the most common measures of particle motion driven by fluctuations and random forces is its diffusivity, which is routinely obtained by measuring the mean squared displacement of the particles. However, often the tracer particles may be moving in a domain or an aggregate which itself experiences some regular or random motion and thus masks the diffusivity of tracers. Here we provide a method for assessing the diffusivity of tracer particles within mobile aggregates by measuring the so-called mean squared relative distance (MSRD) between two tracers. We provide analytical expressions for both the ensemble and time averaged MSRD allowing for direct identification of diffusivities from experimental data.

Estimating the numerical diapycnal mixing in an eddy-permitting ocean model

NASA Astrophysics Data System (ADS)

Megann, Alex

2018-01-01

Constant-depth (or "z-coordinate") ocean models such as MOM4 and NEMO have become the de facto workhorse in climate applications, having attained a mature stage in their development and are well understood. A generic shortcoming of this model type, however, is a tendency for the advection scheme to produce unphysical numerical diapycnal mixing, which in some cases may exceed the explicitly parameterised mixing based on observed physical processes, and this is likely to have effects on the long-timescale evolution of the simulated climate system. Despite this, few quantitative estimates have been made of the typical magnitude of the effective diapycnal diffusivity due to numerical mixing in these models. GO5.0 is a recent ocean model configuration developed jointly by the UK Met Office and the National Oceanography Centre. It forms the ocean component of the GC2 climate model, and is closely related to the ocean component of the UKESM1 Earth System Model, the UK's contribution to the CMIP6 model intercomparison. GO5.0 uses version 3.4 of the NEMO model, on the ORCA025 global tripolar grid. An approach to quantifying the numerical diapycnal mixing in this model, based on the isopycnal watermass analysis of Lee et al. (2002), is described, and the estimates thereby obtained of the effective diapycnal diffusivity in GO5.0 are compared with the values of the explicit diffusivity used by the model. It is shown that the effective mixing in this model configuration is up to an order of magnitude higher than the explicit mixing in much of the ocean interior, implying that mixing in the model below the mixed layer is largely dominated by numerical mixing. This is likely to have adverse consequences for the representation of heat uptake in climate models intended for decadal climate projections, and in particular is highly relevant to the interpretation of the CMIP6 class of climate models, many of which use constant-depth ocean models at ¼° resolution

Dispersion in 2D network: Effects of mixing rule at nodes and molecular diffusion

NASA Astrophysics Data System (ADS)

Wang, Y.; Tao, Q.; Li, M.

2017-12-01

We simulate solute transport in 2D network backbone characterized by pore connectivity and pore heterogeneity by particle-tracking method. In order to ensure the dispersion coefficient reaching an asymptotic value, we upscale dispersion from pore-scale to meter-scale by using periodic boundary condition. As comparison, two different flow mechanisms without or with dispersion in a capillary tube, namely mean flow and Taylor-Aris dispersion, are introduced to investigate the evolution of solute spreading. The longitudinal dispersion coefficient DLM without dispersion in a pipe can roughly be regarded as a parameter to quantify the impact of microscopic structure of porous media on solute spreading, which is smaller than that value DL of Taylor-Aris dispersion. The difference between them decreases with the enhancement of the disorder. The mixing rule at nodes has a minor effect on longitudinal spreading, but has a significant effect on transverse spreading, especially for the nearly homogeneous media. An increase of the disorder in network achieved by increasing pore size heterogeneity or/and decreasing pore connectivity diminishes the difference between two mixing rules. Besides, the evolution of longitudinal dispersion coefficient over diffusion presents three different patterns at different velocities for homogenous media, such as monotonically increasing trend, decreasing first and then increasing trend and monotonically decreasing trend. But all are replaced by power law for a high disorder. The simulation results also accurately predict the experimental dependence of the longitudinal coefficient on Peclet number Pe.

A Study on the Characteristics of Design Variables for IRSS Diffuser

NASA Astrophysics Data System (ADS)

Cho, Yong-Jin; Ko, Dae-Eun

2017-11-01

In modern naval ships, infrared signature suppression systems (IRSS) are installed to decrease the temperature of waste gas generated in propulsion engine and the metallic surface temperature of heated exhaust pipes. Generally, IRSS is composed of eductor, mixing tube, and diffuser. Diffuser serves to reduce the temperature by creating an air film using the pressure difference between internal gas and external air. In this study, design variables were selected by analyzing the diffuser and the characteristics of design variables that affect the performance of diffuser were examined using Taguchi experiment method. For the diffuser performance analysis, a heat flow analysis technique established in previous research was used. The IRSS performance evaluation was carried out based on the average area value of the metal surface temperature and the temperature of the exhaust gas at the outlet of the diffuser, which are variables directly related to the intensity of infrared signature in naval ships. It was verified that the exhaust gas temperature is greatly affected by changes in the diameter of the diffuser outlet, and the metal surface temperature of diffuser is greatly affected by changes in the number of diffuser rings.

Charged BTZ-like black hole solutions and the diffusivity-butterfly velocity relation

NASA Astrophysics Data System (ADS)

Ge, Xian-Hui; Sin, Sang-Jin; Tian, Yu; Wu, Shao-Feng; Wu, Shang-Yu

2018-01-01

We show that there exists a class of charged BTZ-like black hole solutions in Lifshitz spacetime with a hyperscaling violating factor. The charged BTZ black hole is characterized by a charge-dependent logarithmic term in the metric function. As concrete examples, we give five such charged BTZ-like black hole solutions and the standard charged BTZ metric can be regarded as a special instance of them. In order to check the recent proposed universal relations between diffusivity and the butterfly velocity, we first compute the diffusion constants of the standard charged BTZ black holes and then extend our calculation to arbitrary dimension d, exponents z and θ. Remarkably, the case d = θ and z = 2 is a very special in that the charge diffusion D c is a constant and the energy diffusion D e might be ill-defined, but v B 2 τ diverges. We also compute the diffusion constants for the case that the DC conductivity is finite but in the absence of momentum relaxation.

Exploring Ivorian perspectives on the effectiveness of the current Ivorian science curriculum in addressing issues related to HIV/AIDS

NASA Astrophysics Data System (ADS)

Ado, Gustave Firmin

School-based HIV/AIDS science education has the potential to impact students when integrated into the science curriculum. However, this mixed method study shows that school-based HIV/AIDS science education is often not infused into career subjects such as science education but integrated into civics education and taught by teachers who lack the skills, knowledge, and the training in the delivery of effective school HIV/AIDS education. Since science is where biological events take place, it is suggested that HIV/AIDS science merits being taught in the science education classroom. This study took place in nine public middle schools within two school districts in Abidjan, Ivory Coast, one major urban city in the southern region. The study utilized triangulation of multiple data sources---both qualitative and quantitative. To substantiate the claims made in this study, a range of qualitative methods such as field notes and individual interviews with 39 teachers, 63 sixth grade students, 8 school administrators, and 20 community elders were used. For the quantitative portion 140 teachers and 3510 sixth grade students were surveyed. The findings from the study prioritize science education that includes HIV/AIDS science education for all, with emphasis on HIV/AIDS prevention in Ivory Coast. The factors that influence the implementation of HIV/AIDS curricula within the Ivorian sixth grade classrooms are discussed. Interview and survey data from students, teachers, school administrators, and community elders indicate that in the Ivorian school setting, "gerontocratic" cultural influences, religious beliefs, personal cultural beliefs, and time spent toward the discourse on HIV/AIDS have led to HIV/AIDS education that is often insufficient to change either misconceptions about HIV/AIDS or risky practices. It was also found that approaches to teaching HIV/AIDS does not connect with youth cultures. By reframing and integrating current HIV/AIDS curricula into the science

Creating Social Spaces to Tackle AIDS-Related Stigma: Reviewing the Role of Church Groups in Sub-Saharan Africa

PubMed Central

Skovdal, M.; Gibbs, A.

2012-01-01

An expanding body of literature explores the role of African church groups in facilitating or hindering the support of people living with AIDS and challenging or contributing to HIV/AIDS-related stigma. Treating church groups as social spaces in which HIV/AIDS-related stigma may potentially be challenged, we systematically review this literature, identifying five themes that highlight the complex and contradictory role of the church as a potential agent of health-enhancing social change. In many ways the church perpetuates HIV/AIDS-related stigma through (i) moralistic attitudes and (ii) its reinforcement of conservative gender ideologies. However some churches have managed move towards action that makes a more positive contribution to HIV/AIDS management through (iii) promoting various forms of social control for HIV prevention, (iv) contributing to the care and support of the AIDS-affected and (v) providing social spaces for challenging stigmatising ideas and practices. We conclude that church groups, including church leadership, can play a key role in facilitating or hindering the creation of supportive social spaces to challenge stigma. Much work remains to be done in developing deeper understandings of the multi-layered factors that enable some churches, but not others, to respond effectively to HIV/AIDS. PMID:20668927

Creating social spaces to tackle AIDS-related stigma: reviewing the role of church groups in Sub-Saharan Africa.

PubMed

Campbell, C; Skovdal, M; Gibbs, A

2011-08-01

An expanding body of literature explores the role of African church groups in facilitating or hindering the support of people living with AIDS and challenging or contributing to HIV/AIDS-related stigma. Treating church groups as social spaces in which HIV/AIDS-related stigma may potentially be challenged, we systematically review this literature, identifying five themes that highlight the complex and contradictory role of the church as a potential agent of health-enhancing social change. In many ways the church perpetuates HIV/AIDS-related stigma through (i) moralistic attitudes and (ii) its reinforcement of conservative gender ideologies. However some churches have managed move towards action that makes a more positive contribution to HIV/AIDS management through (iii) promoting various forms of social control for HIV prevention, (iv) contributing to the care and support of the AIDS-affected and (v) providing social spaces for challenging stigmatising ideas and practices. We conclude that church groups, including church leadership, can play a key role in facilitating or hindering the creation of supportive social spaces to challenge stigma. Much work remains to be done in developing deeper understandings of the multi-layered factors that enable some churches, but not others, to respond effectively to HIV/AIDS.

Theoretical Relationships between Luminescence and Hillslope Soil Vertical Diffusivity: a Numerical Modeling Approach

NASA Astrophysics Data System (ADS)

Gray, H. J.; Tucker, G. E.; Mahan, S.

2017-12-01

Luminescence is a property of matter that can be used to obtain depositional ages from fine sand. Luminescence generates due to exposure to background ionizing radiation and is removed by sunlight exposure in a process known as bleaching. There is evidence to suggest that luminescence can also serve as a sediment tracer in fluvial and hillslope environments. For hillslope environments, it has been suggested that the magnitude of luminescence as a function of soil depth is related to the strength of soil mixing. Hillslope soils with a greater extent of mixing will have previously surficial sand grains moved to greater depths in a soil column. These previously surface-exposed grains will contain a lower luminescence than those which have never seen the surface. To attempt to connect luminescence profiles with soil mixing rate, here defined as the soil vertical diffusivity, I conduct numerical modelling of particles in hillslope soils coupled with equations describing the physics of luminescence. I use recently published equations describing the trajectories of particles under both exponential and uniform soil velocity soils profiles and modify them to include soil diffusivity. Results from the model demonstrates a strong connection between soil diffusivity and luminescence. Both the depth profiles of luminescence and the total percent of surface exposed grains will change drastically based on the magnitude of the diffusivity. This suggests that luminescence could potentially be used to infer the magnitude of soil diffusivity. However, I test other variables such as the soil production rate, e-folding length of soil velocity, background dose rate, and soil thickness, and I find these other variables can also affect the relationship between luminescence and diffusivity. This suggests that these other variables may need to be constrained prior to any inferences of soil diffusivity from luminescence measurements. Further field testing of the model in areas where the soil

Atomic mixing induced by swift heavy ion irradiation of Fe/Zr multilayers

NASA Astrophysics Data System (ADS)

Jaouen, C.; Michel, A.; Pacaud, J.; Dufour, C.; Bauer, Ph.; Gervais, B.

1999-01-01

The mechanism of ion induced mixing and phase change was studied for Fe/Zr multilayers, and specifically for the case of swift heavy ions giving rise to a very large electronic excitation of the target. The multilayers had a modulation of 7.6 nm and an overall composition Fe 69Zr 31. The Zr layers were amorphous whereas the Fe ones were crystalline (bcc) with a very strong (1 1 0) texture in the growth direction. The phase transformation and the composition changes were analysed using the structural and magnetic properties of the Fe component by means of a detailed analysis of the X-ray diffraction profiles and with the aid of backscattering Mössbauer spectroscopy. A complete mixing was observed at a fluence of 10 13 U/cm 2. Both phenomena, the dose dependence of the ion beam mixed amorphous non-magnetic phase and the quantitative evolution of the crystalline iron layer thickness, suggest that mixing occurs in a two-stage process. At an initial stage, an anisotropic diffusion of iron atoms in the amorphous zirconium layers takes place along the interface, while subsequent ion bombardment leads to a generalised transformation through the whole of the Fe layer. Finally, the implications of these observations are discussed in comparison to the plastic deformation phenomena reported for amorphous alloys.

Diffusion and related transport mechanisms in brain tissue

NASA Astrophysics Data System (ADS)

Nicholson, Charles

2001-07-01

Diffusion plays a crucial role in brain function. The spaces between cells can be likened to the water phase of a foam and many substances move within this complicated region. Diffusion in this interstitial space can be accurately modelled with appropriate modifications of classical equations and quantified from measurements based on novel micro-techniques. Besides delivering glucose and oxygen from the vascular system to brain cells, diffusion also moves informational substances between cells, a process known as volume transmission. Deviations from expected results reveal how local uptake, degradation or bulk flow may modify the transport of molecules. Diffusion is also essential to many therapies that deliver drugs to the brain. The diffusion-generated concentration distributions of well-chosen molecules also reveal the structure of brain tissue. This structure is represented by the volume fraction (void space) and the tortuosity (hindrance to diffusion imposed by local boundaries or local viscosity). Analysis of these parameters also reveals how the local geometry of the brain changes with time or under pathological conditions. Theoretical and experimental approaches borrow from classical diffusion theory and from porous media concepts. Earlier studies were based on radiotracers but the recent methods use a point-source paradigm coupled with micro-sensors or optical imaging of macromolecules labelled with fluorescent tags. These concepts and methods are likely to be applicable elsewhere to measure diffusion properties in very small volumes of highly structured but delicate material.

Diagnosing isopycnal diffusivity in an eddying, idealized midlatitude ocean basin via Lagrangian, in Situ, Global, High-Performance Particle Tracking (LIGHT)

DOE PAGES

Wolfram, Phillip J.; Ringler, Todd D.; Maltrud, Mathew E.; ...

2015-08-01

Isopycnal diffusivity due to stirring by mesoscale eddies in an idealized, wind-forced, eddying, midlatitude ocean basin is computed using Lagrangian, in Situ, Global, High-Performance Particle Tracking (LIGHT). Simulation is performed via LIGHT within the Model for Prediction across Scales Ocean (MPAS-O). Simulations are performed at 4-, 8-, 16-, and 32-km resolution, where the first Rossby radius of deformation (RRD) is approximately 30 km. Scalar and tensor diffusivities are estimated at each resolution based on 30 ensemble members using particle cluster statistics. Each ensemble member is composed of 303 665 particles distributed across five potential density surfaces. Diffusivity dependence upon modelmore » resolution, velocity spatial scale, and buoyancy surface is quantified and compared with mixing length theory. The spatial structure of diffusivity ranges over approximately two orders of magnitude with values of O(10 5) m 2 s –1 in the region of western boundary current separation to O(10 3) m 2 s –1 in the eastern region of the basin. Dominant mixing occurs at scales twice the size of the first RRD. Model resolution at scales finer than the RRD is necessary to obtain sufficient model fidelity at scales between one and four RRD to accurately represent mixing. Mixing length scaling with eddy kinetic energy and the Lagrangian time scale yield mixing efficiencies that typically range between 0.4 and 0.8. In conclusion, a reduced mixing length in the eastern region of the domain relative to the west suggests there are different mixing regimes outside the baroclinic jet region.« less

Diffusion in confinement: kinetic simulations of self- and collective diffusion behavior of adsorbed gases

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

Abouelnasr, MKF; Smit, B

2012-01-01

The self- and collective-diffusion behaviors of adsorbed methane, helium, and isobutane in zeolite frameworks LTA, MFI, AFI, and SAS were examined at various concentrations using a range of molecular simulation techniques including Molecular Dynamics (MD), Monte Carlo (MC), Bennett-Chandler (BC), and kinetic Monte Carlo (kMC). This paper has three main results. (1) A novel model for the process of adsorbate movement between two large cages was created, allowing the formulation of a mixing rule for the re-crossing coefficient between two cages of unequal loading. The predictions from this mixing rule were found to agree quantitatively with explicit simulations. (2) Amore » new approach to the dynamically corrected Transition State Theory method to analytically calculate self-diffusion properties was developed, explicitly accounting for nanoscale fluctuations in concentration. This approach was demonstrated to quantitatively agree with previous methods, but is uniquely suited to be adapted to a kMC simulation that can simulate the collective-diffusion behavior. (3) While at low and moderate loadings the self- and collective-diffusion behaviors in LTA are observed to coincide, at higher concentrations they diverge. A change in the adsorbate packing scheme was shown to cause this divergence, a trait which is replicated in a kMC simulation that explicitly models this behavior. These phenomena were further investigated for isobutane in zeolite MFI, where MD results showed a separation in self- and collective-diffusion behavior that was reproduced with kMC simulations.« less

Diffusion in confinement: kinetic simulations of self- and collective diffusion behavior of adsorbed gases.

PubMed

Abouelnasr, Mahmoud K F; Smit, Berend

2012-09-07

The self- and collective-diffusion behaviors of adsorbed methane, helium, and isobutane in zeolite frameworks LTA, MFI, AFI, and SAS were examined at various concentrations using a range of molecular simulation techniques including Molecular Dynamics (MD), Monte Carlo (MC), Bennett-Chandler (BC), and kinetic Monte Carlo (kMC). This paper has three main results. (1) A novel model for the process of adsorbate movement between two large cages was created, allowing the formulation of a mixing rule for the re-crossing coefficient between two cages of unequal loading. The predictions from this mixing rule were found to agree quantitatively with explicit simulations. (2) A new approach to the dynamically corrected Transition State Theory method to analytically calculate self-diffusion properties was developed, explicitly accounting for nanoscale fluctuations in concentration. This approach was demonstrated to quantitatively agree with previous methods, but is uniquely suited to be adapted to a kMC simulation that can simulate the collective-diffusion behavior. (3) While at low and moderate loadings the self- and collective-diffusion behaviors in LTA are observed to coincide, at higher concentrations they diverge. A change in the adsorbate packing scheme was shown to cause this divergence, a trait which is replicated in a kMC simulation that explicitly models this behavior. These phenomena were further investigated for isobutane in zeolite MFI, where MD results showed a separation in self- and collective- diffusion behavior that was reproduced with kMC simulations.

Diffusive Phenomena and the Austenite/Martensite Relative Stability in Cu-Based Shape-Memory Alloys

NASA Astrophysics Data System (ADS)

Pelegrina, J. L.; Yawny, A.; Sade, M.

2018-03-01

The main characteristic of martensitic phase transitions is the coordinate movement of the atoms which takes place athermally, without the contribution of diffusion during its occurrence. However, the impacts of diffusive phenomena on the relative stability between the phases involved and, consequently, on the associated transformation temperatures and functional properties can be significant. This is particularly evident in the case of Cu-based shape-memory alloys where atomic diffusion in both austenite and martensite metastable phases might occur even at room-temperature levels, giving rise to a variety of intensively studied phenomena. In the present study, the progresses made in the understanding of three selected diffusion-related effects of importance in Cu-Zn-Al and Cu-Al-Be alloys are reviewed. They are the after-quench retained disorder in the austenitic structure and its subsequent reordering, the stabilization of the martensite, and the effect of applied stress on the austenitic order. It is shown how the experimental results obtained from tests performed on single crystal material can be rationalized under the shed of a model developed to evaluate the variation of the relative stability between the phases in terms of atom pairs interchanges.

Diffusive Phenomena and the Austenite/Martensite Relative Stability in Cu-Based Shape-Memory Alloys

NASA Astrophysics Data System (ADS)

Pelegrina, J. L.; Yawny, A.; Sade, M.

2018-02-01

The main characteristic of martensitic phase transitions is the coordinate movement of the atoms which takes place athermally, without the contribution of diffusion during its occurrence. However, the impacts of diffusive phenomena on the relative stability between the phases involved and, consequently, on the associated transformation temperatures and functional properties can be significant. This is particularly evident in the case of Cu-based shape-memory alloys where atomic diffusion in both austenite and martensite metastable phases might occur even at room-temperature levels, giving rise to a variety of intensively studied phenomena. In the present study, the progresses made in the understanding of three selected diffusion-related effects of importance in Cu-Zn-Al and Cu-Al-Be alloys are reviewed. They are the after-quench retained disorder in the austenitic structure and its subsequent reordering, the stabilization of the martensite, and the effect of applied stress on the austenitic order. It is shown how the experimental results obtained from tests performed on single crystal material can be rationalized under the shed of a model developed to evaluate the variation of the relative stability between the phases in terms of atom pairs interchanges.

New Layer Thickness Parameterization of Diffusive Convection

NASA Astrophysics Data System (ADS)

Zhou, Sheng-Qi; Lu, Yuan-Zheng; Guo, Shuang-Xi; Song, Xue-Long; Qu, Ling; Cen, Xian-Rong; Fer, Ilker

2017-11-01

Double-diffusion convection is one of the most important non-mechanically driven mixing processes. Its importance has been particular recognized in oceanography, material science, geology, and planetary physics. Double-diffusion occurs in a fluid in which there are gradients of two (or more) properties with different molecular diffusivities and of opposing effects on the vertical density distribution. It has two primary modes: salt finger and diffusive convection. Recently, the importance of diffusive convection has aroused more interest due to its impact to the diapycnal mixing in the interior ocean and the ice and the ice-melting in the Arctic and Antarctic Oceans. In our recent work, we constructed a length scale of energy-containing eddy and proposed a new layer thickness parameterization of diffusive convection by using the laboratory experiment and in situ observations in the lakes and oceans. The new parameterization can well describe the laboratory convecting layer thicknesses (0.01 0.1 m) and those observed in oceans and lakes (0.1 1000 m). This work was supported by China NSF Grants (41476167,41406035 and 41176027), NSF of Guangdong Province, China (2016A030311042) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11030302).

Relation between the neutrino flux from Centaurus A and the associated diffuse neutrino flux

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

Koers, Hylke B. J.; Tinyakov, Peter; Institute for Nuclear Research, 60th October Anniversary Prospect 7a, 117312, Moscow

2008-10-15

Based on recent results obtained by the Pierre Auger Observatory (PAO), it has been hypothesized that Centaurus A (Cen A) is a source of ultrahigh-energy cosmic rays (UHECRs) and associated neutrinos. We point out that the diffuse neutrino flux may be used to constrain the source model if one assumes that the ratio between the UHECR and neutrino fluxes outputted by Cen A is representative for other sources. Under this assumption we investigate the relation between the neutrino flux from Cen A and the diffuse neutrino flux. Assuming furthermore that Cen A is the source of two UHECR events observedmore » by PAO, we estimate the all-sky diffuse neutrino flux to be {approx}200-5000 times larger than the neutrino flux from Cen A. As a result, the diffuse neutrino fluxes associated with some of the recently proposed models of UHECR-related neutrino production in Cen A are above existing limits. Regardless of the underlying source model, our results indicate that the detection of neutrinos from Cen A without the accompanying diffuse flux would mean that Cen A is an exceptionally efficient neutrino source.« less

Control of flow separation and mixing by aerodynamic excitation

NASA Technical Reports Server (NTRS)

Rice, Edward J.; Abbott, John M.

1990-01-01

The recent research in the control of shear flows using unsteady aerodynamic excitation conducted at the NASA Lewis Research Center is reviewed. The program is of a fundamental nature, concentrating on the physics of the unsteady aerodynamic processes. This field of research is a fairly new development with great promise in the areas of enhanced mixing and flow separation control. Enhanced mixing research includes influence of core turbulence, forced pairing of coherent structures, and saturation of mixing enhancement. Separation flow control studies included are for a two-dimensional diffuser, conical diffusers, and single airfoils. Ultimate applications include aircraft engine inlet flow control at high angle of attack, wide angle diffusers, highly loaded airfoils as in turbomachinery, and ejector/suppressor nozzles for the supersonic transport. An argument involving the Coanda Effect is made that all of the above mentioned application areas really only involve forms of shear layer mixing enhancement. The program also includes the development of practical excitation devices which might be used in aircraft applications.

Relative phase shifts for metaplectic isotopies acting on mixed Gaussian states

NASA Astrophysics Data System (ADS)

de Gosson, Maurice A.; Nicacio, Fernando

2018-05-01

We address in this paper the notion of relative phase shift for mixed quantum systems. We study the Pancharatnam-Sjöqvist phase shift φ (t ) =ArgTr(U^ tρ ^ ) for metaplectic isotopies acting on Gaussian mixed states. We complete and generalize the previous results obtained by one of us, while giving rigorous proofs. The key actor in this study is the theory of the Conley-Zehnder index which is an intersection index related to the Maslov index.

Prevalence of "HIV/AIDS related" parental death and its association with sexual behavior of secondary school youth in Addis Ababa, Ethiopia: a cross sectional study.

PubMed

Menna, Takele; Ali, Ahmed; Worku, Alemayehu

2014-10-30

Human immunodeficiency virus infection is a global crisis that represents a serious health threat, particularly among younger people. Various studies show that both orphan and non-orphan adolescents and youths experience vulnerability to HIV. Nevertheless, the findings hitherto are mixed and inconclusive. The aim of this study, therefore, was to assess the prevalence of parental death and its association with multiple sexual partners among secondary school students for evidence based interventions. A cross-sectional study was conducted among secondary school youth in Addis Ababa, Ethiopia. A multistage sampling technique was used to select a representative sample of 2,169 school youths. Sexual health behavior related data were collected using self-administered questionnaire. Binary logistic regression was employed to examine the relation between parental death and multiple sexual partners. Among the 2,169 eligible study participants 1948 (90%) completed the self-administered questionnaires. Of those 1,182(60.7%) were females. The overall prevalence of parental death was 347(17.8%.) with 95% CI (16.2%, 19.6%). The HIV/AIDS proportionate mortality ratio was 28% (97/347).A multivariate logistic regression analysis showed that high HIV/AIDS related knowledge (AOR = 0.39; 95% CI, 0.18-0.84), positive attitude towards HIV prevention methods (AOR = 0.48; 95% CI, 0.23-0.97), being tested for HIV (AOR = 0.52; 95% CI, 0.31-0.87) and chewing Khat (AOR = 2.59; 95% CI,1.28-5.26)] were significantly associated with having multiple sexual partners among secondary school youths. Significant proportion of secondary school youths had lost at least one parent due to various causes. High knowledge of HIV/AIDS, positive attitude towards 'ABC' rules for HIV prevention, being tested for HIV and chewing khat are more likely to be factors associated with multiple sexual partnership among secondary school students in Addis Ababa.Therefore, the school based interventions

Comparison of Apparent Diffusion Coefficient and Intravoxel Incoherent Motion for Differentiating among Glioblastoma, Metastasis, and Lymphoma Focusing on Diffusion-Related Parameter.

PubMed

Shim, Woo Hyun; Kim, Ho Sung; Choi, Choong-Gon; Kim, Sang Joon

2015-01-01

Brain tumor cellularity has been assessed by using apparent diffusion coefficient (ADC). However, the ADC value might be influenced by both perfusion and true molecular diffusion, and the perfusion effect on ADC can limit the reliability of ADC in the characterization of tumor cellularity, especially, in hypervascular brain tumors. In contrast, the IVIM technique estimates parameter values for diffusion and perfusion effects separately. The purpose of our study was to compare ADC and IVIM for differentiating among glioblastoma, metastatic tumor, and primary CNS lymphoma (PCNSL) focusing on diffusion-related parameter. We retrospectively reviewed the data of 128 patients with pathologically confirmed glioblastoma (n = 55), metastasis (n = 31), and PCNSL (n = 42) prior to any treatment. Two neuroradiologists independently calculated the maximum IVIM-f (fmax) and minimum IVIM-D (Dmin) by using 16 different b-values with a bi-exponential fitting of diffusion signal decay, minimum ADC (ADCmin) by using 0 and 1000 b-values with a mono-exponential fitting and maximum normalized cerebral blood volume (nCBVmax). The differences in fmax, Dmin, nCBVmax, and ADCmin among the three tumor pathologies were determined by one-way ANOVA with multiple comparisons. The fmax and Dmin were correlated to the corresponding nCBV and ADC using partial correlation analysis, respectively. Using a mono-exponential fitting of diffusion signal decay, the mean ADCmin was significantly lower in PCNSL than in glioblastoma and metastasis. However, using a bi-exponential fitting, the mean Dmin did not significantly differ in the three groups. The mean fmax significantly increased in the glioblastomas (reader 1, 0.103; reader 2, 0.109) and the metastasis (reader 1, 0.105; reader 2, 0.107), compared to the primary CNS lymphomas (reader 1, 0.025; reader 2, 0.023) (P < .001 for each). The correlation between fmax and the corresponding nCBV was highest in glioblastoma group, and the correlation between

Fuel-Air Mixing and Combustion in Scramjets

NASA Technical Reports Server (NTRS)

Drummond, J. P.; Diskin, Glenn S.; Cutler, A. D.

2002-01-01

Activities in the area of scramjet fuel-air mixing and combustion associated with the Research and Technology Organization Working Group on Technologies for Propelled Hypersonic Flight are described. Work discussed in this paper has centered on the design of two basic experiments for studying the mixing and combustion of fuel and air in a scramjet. Simulations were conducted to aid in the design of these experiments. The experimental models were then constructed, and data were collected in the laboratory. Comparison of the data from a coaxial jet mixing experiment and a supersonic combustor experiment with a combustor code were then made and described. This work was conducted by NATO to validate combustion codes currently employed in scramjet design and to aid in the development of improved turbulence and combustion models employed by the codes.

Diffusion related isotopic fractionation effects with one-dimensional advective-dispersive transport.

PubMed

Xu, Bruce S; Lollar, Barbara Sherwood; Passeport, Elodie; Sleep, Brent E

2016-04-15

Aqueous phase diffusion-related isotope fractionation (DRIF) for carbon isotopes was investigated for common groundwater contaminants in systems in which transport could be considered to be one-dimensional. This paper focuses not only on theoretically observable DRIF effects in these systems but introduces the important concept of constraining "observable" DRIF based on constraints imposed by the scale of measurements in the field, and on standard limits of detection and analytical uncertainty. Specifically, constraints for the detection of DRIF were determined in terms of the diffusive fractionation factor, the initial concentration of contaminants (C0), the method detection limit (MDL) for isotopic analysis, the transport time, and the ratio of the longitudinal mechanical dispersion coefficient to effective molecular diffusion coefficient (Dmech/Deff). The results allow a determination of field conditions under which DRIF may be an important factor in the use of stable carbon isotope measurements for evaluation of contaminant transport and transformation for one-dimensional advective-dispersive transport. This study demonstrates that for diffusion-dominated transport of BTEX, MTBE, and chlorinated ethenes, DRIF effects are only detectable for the smaller molar mass compounds such as vinyl chloride for C0/MDL ratios of 50 or higher. Much larger C0/MDL ratios, corresponding to higher source concentrations or lower detection limits, are necessary for DRIF to be detectable for the higher molar mass compounds. The distance over which DRIF is observable for VC is small (less than 1m) for a relatively young diffusive plume (<100years), and DRIF will not easily be detected by using the conventional sampling approach with "typical" well spacing (at least several meters). With contaminant transport by advection, mechanical dispersion, and molecular diffusion this study suggests that in field sites where Dmech/Deff is larger than 10, DRIF effects will likely not be

Individual and organizational predictors of health care aide job satisfaction in long term care.

PubMed

Chamberlain, Stephanie A; Hoben, Matthias; Squires, Janet E; Estabrooks, Carole A

2016-10-13

Unregulated health care aides provide the majority of direct health care to residents in long term care homes. Lower job satisfaction as reported by care aides is associated with increased turnover of staff. Turnover leads to inferior job performance and negatively impacts quality of care for residents. This study aimed to determine the individual and organizational variables associated with job satisfaction in care aides. We surveyed a sample of 1224 care aides from 30 long term care homes in three Western Canadian provinces. The care aides reported their job satisfaction and their perception of the work environment. We used a hierarchical, mixed-effects ordered logistic regression to model the relative odds of care aide job satisfaction for individual, care unit, and facility factors. Care aide exhaustion, professional efficacy, and cynicism were associated with job satisfaction. Factors in the organizational context that are associated with increased care aide job satisfaction include: leadership, culture, social capital, organizational slack-staff, organizational slack-space, and organizational slack-time. Our findings suggest that organizational factors account for a greater increase in care aide job satisfaction than do individual factors. These features of the work environment are modifiable and predict care aide job satisfaction. Efforts to improve care aide work environment and quality of care should focus on organizational context.

A Physical Mechanism for the Asymmetry in Top-Down and Bottom-Up Diffusion.

NASA Astrophysics Data System (ADS)

Wyngaard, J. C.

1987-04-01

Recent large-eddy simulations of the vertical diffusion of a passive, conservative scalar through the convective boundary layer (CBL) show strikingly different eddy diffusivity profiles in the `top-down' and `bottom-up' cases. These results indicate that for a given turbulent velocity field and associated scalar flux, the mean change in scalar mixing ratio across the CBL is several times larger if the flux originates at the top of the boundary layer (i.e., in top-down diffusion) rather than at the bottom. The large-eddy simulation (LES) data show that this asymmetry is due to a breakdown of the eddy-diffusion concept.A simple updraft-downdraft model of the CBL reveals a physical mechanism that could cause this unexpected behavior. The large, positive skewness of the convectively driven vertical velocity gives an appreciably higher probability of downdrafts than updrafts; this excess probability of downdrafts, interacting with the time changes of the mean mixing ratio caused by the nonstationarity of the bottom-up and top-down diffusion processes, decreases the equilibrium value of mean mixing-ratio jump across the mixed layer in the bottom-up case and increases it in the top-down case. The resulting diffusion asymmetry agrees qualitatively with that found through LES.

Orphanhood by AIDS-Related Causes and Child Mental Health: A Developmental Psychopathology Approach

PubMed Central

Sharp, Carla; Jardin, Charles; Marais, Lochner; Boivin, Michael

2016-01-01

While the number of new HIV infections has declined, the number of orphans as a result of AIDS-related deaths continues to increase. The aim of this paper was to systematically review empirical research on the mental health of children affected by HIV/AIDS in the developing world, specifically with an eye on developing a theoretical framework to guide intervention and research. Articles for review were gathered by following the Preferred Reporting Items for Systemic Reviews and Meta Analyses (PRISMA standards), reviewed and then organized and synthesized with a Developmental Psychopathology framework. Results showed that the immediate and longterm effects of AIDS orphanhood are moderated by a number of important risk and protective factors that may serve as strategic targets for intervention. Research and clinical implications are discussed. PMID:27668289

[Analysis of HIV/AIDS related risk behaviors and their impact factors among out-of-school adolescents in outflow areas].

PubMed

Sun, Xiao; Zhu, Guang-rong; Ji, Cheng-ye; Wang, Zhen-zhen

2012-06-18

To analyze HIV/AIDS related risk behaviors among unmarried outside school adolescents and the impact factors in outflow areas, in order to provide basis for related health education. Using cluster sampling method, we investigated a vocational training center for all 15- to 24-year-old unmarried outside school youths in one county. The structured questionnaire based on the Theory of Reasoned Action was anonymous, which filled envelopes on the spot. A total of 1 800 questionnaires were recovered, and 1 712 questionnaires were valid. Epidata 3.0 was used for establishing a database and SPSS 13.0 for statistical analysis. (1) The incidence of HIV/AIDS risk behaviors of the outside school adolescents was high: 18.0% of the respondents had sexual behavior, 27.3% had never used condom when sexed in the past three months, 31.0% had multiple sexual partners, and 9.7% had drug abuse experience; the rate of HIV/AIDS-related knowledge was only 25.1%; peer environment of respondents was poor. (2) The use of condoms was correlated with those who had higher score of AIDS knowledge, and who could talk about condoms in sexual intercourse; The multiple sexual partners' behavior was correlated with age, friends who were themselves multiple sexual partners, high score of the attitude, and the subjective norm; The commercial sex was correlated with the family address, high score of the HIV/AIDS-related knowledge, friends who had commercial sex, the subjective norm and the intention of behavior, The drug abuse behavior was correlated with age, high score of the HIV/AIDS-related knowledge, drug abuse among their friends, the subjective norm, and the intention of behavior. (3) Subjective norms and behavioral intentions could better predict the occurrence of HIV/AIDS risk behaviors. The outside school adolescents are at risk in lack of HIV/AIDS-related knowledge and coping skills of negative peer pressure, so providing the related health education before they go and work outside their home

Treatment Option Overview (AIDS Related-Lymphoma)

MedlinePlus

... which malignant (cancer) cells form in the lymph system of patients who have acquired immunodeficiency syndrome (AIDS). ... below the ribs. Tests that examine the lymph system and other parts of the body are used ...

Exploring AIDS-related knowledge, attitudes, and behaviors of female Mexican migrant workers.

PubMed

Organista, P B; Organista, K C; Soloff, P R

1998-05-01

AIDS-related knowledge, attitudes, and behaviors were assessed in female Mexican migrant laborers. Thirty-two women were administered a modified version of the Hispanic Condom Questionnaire. Respondents were knowledgeable about the major modes of HIV transmission, but one-third to one-half of the women believed that they could contract AIDS from unlikely casual sources. Although respondents reported few negative beliefs about condom use, actual condom use with sex partners was low and knowledge of proper condom use was problematic. Consequently, 75 percent reported never carrying condoms. Implications of these findings for future research and provision of services for female Mexican migrants are discussed.

Transient Liquid-Phase Diffusion Bonding of Aluminum Metal Matrix Composite Using a Mixed Cu-Ni Powder Interlayer

NASA Astrophysics Data System (ADS)

Maity, Joydeep; Pal, Tapan Kumar

2012-07-01

In the present study, the transient liquid-phase diffusion bonding of an aluminum metal matrix composite (6061-15 wt.% SiCp) has been investigated for the first time using a mixed Cu-Ni powder interlayer at 560 °C, 0.2 MPa, for different holding times up to 6 h. The microstructure of the isothermally solidified zone contains equilibrium precipitate CuAl2, metastable precipitate Al9Ni2 in the matrix of α-solid solution along with the reinforcement particles (SiC). On the other hand, the microstructure of the central bond zone consists of equilibrium phases such as NiAl3, Al7Cu4Ni and α-solid solution along with SiC particles (without any segregation) and the presence of microporosities. During shear test, the crack originates from microporosities and propagates along the interphase interfaces resulting in poor bond strength for lower holding times. As the bonding time increases, with continual diffusion, the structural heterogeneity is diminished, and the microporosities are eliminated at the central bond zone. Accordingly, after 6-h holding, the microstructure of the central bond zone mainly consists of NiAl3 without any visible microporosity. This provides a joint efficiency of 84% with failure primarily occurring through decohesion at the SiC particle/matrix interface.

AIDS guidelines.

PubMed

Berger, R

1986-04-30

The Sun article, "Employers finding that AIDS in the workplace is a managerial nightmare" (April 3), did not accurately portray the status of AIDS in the workplace. The AIDS virus, HTLV III, is transmitted by body fluids, primarily semen and blood, and there is no known risk of transmitting the virus by casual contact in the workplace. The Center for Disease Control (CDC) released guidelines for child care workers last August. Guidelines on preventing transmission of AIDS in the workplace were issued by CDC in November 1985. These guidelines specifically discussed health care, personal service, and food service workers. The recommendations were against routine screening. Furthermore, employment should not be restricted on the basis of a positive HTLV III antibody test. A person with HTLV III infection should be exempt from the workplace only if there are circumstances interfering with job performance. In Maryland, the Governor's Task Force on AIDS has gone on record as endorsing CDC guidelines related to employment. Furthermore, the task force condemns discrimination based on the disease AIDS, AIDS Related Complex (ARC), or HTLV III infection. Increasingly AIDS patients are being considered legally disabled and therefore are protected by federal and state laws prohibiting discrimination on the basis of a handicap. Marylanders who are subjected to mandatory HTLV III screening in the workplace, or if discriminated against on the basis of HTLV III inefction, should contact the Maryland Commission on Human Relations, the Maryland Department of Health and Mental Hygiene, or the Health Education Resource Organization (HERO). All 3 of these resources guarantee confidentiality. It is only by employees reporting incidents that a nightmare in the workplace can be avoided in Maryland. full text

Lamination and mixing in laminar flows driven by Lorentz body forces

NASA Astrophysics Data System (ADS)

Rossi, L.; Doorly, D.; Kustrin, D.

2012-01-01

We present a new approach to the design of mixers. This approach relies on a sequence of tailored flows coupled with a new procedure to quantify the local degree of striation, called lamination. Lamination translates to the distance over which the molecular diffusion needs to act to finalise mixing. A novel in situ mixing is achieved by the tailored sequence of flows. This sequence is shown with the property that material lines and lamination grow exponentially, according to processes akin to the well-known baker's map. The degree of mixing (stirring coefficient) likewise shows exponential growth before the saturation of the stirring rate. Such saturation happens when the typical striations' thickness is smaller than the diffusion's length scale. Moreover, without molecular diffusion, the predicted striations' thickness would be smaller than the size of an atom of hydrogen within 40 flow turnover times. In fact, we conclude that about 3 minutes, i.e. 15 turnover times, are sufficient to mix species with very low diffusivities, e.g. suspensions of virus, bacteria, human cells, and DNA.

Generalized Einstein relation for the mutual diffusion coefficient of a binary fluid mixture.

PubMed

Felderhof, B U

2017-08-21

The method employed by Einstein to derive his famous relation between the diffusion coefficient and the friction coefficient of a Brownian particle is used to derive a generalized Einstein relation for the mutual diffusion coefficient of a binary fluid mixture. The expression is compared with the one derived by de Groot and Mazur from irreversible thermodynamics and later by Batchelor for a Brownian suspension. A different result was derived by several other workers in irreversible thermodynamics. For a nearly incompressible solution, the generalized Einstein relation agrees with the expression derived by de Groot and Mazur. The two expressions also agree to first order in solute density. For a Brownian suspension, the result derived from the generalized Smoluchowski equation agrees with both expressions.

Mixed cellulose ester filter as a separator for air-diffusion cathode microbial fuel cells.

PubMed

Wang, Zejie; Lim, Bongsu

2017-04-01

Separator is important to prevent bio-contamination of the catalyst layer of air-diffusion cathode microbial fuel cells (MFCs). Mixed cellulose ester filter (MCEF) was examined as a separator for an air-cathode MFC in the present study. The MCEF-MFC produced a maximum power density of 780.7 ± 18.7 mW/m 2 , which was comparable to 770.9 ± 35.9 mW/m 2 of MFC with Nafion membrane (NFM) as a separator. Long-term examination demonstrated a more stable performance of the MCEF-MFC than NFM-MFC. After 25 cycles, the maximum voltage of the MCEF-MFC decreased by only 1.3% from 425.1 ± 4.3 mV (initial 5 cycles) to 419.5 ± 2.3 mV (last 5 cycles). However, it was decreased by 9.1% from 424.8 ± 5.7 to 386 ± 2.5 mV for the NFM-MFC. The coulombic efficiency (CE) of the MCEF-MFC did not change (from 3.11 ± 0.09% to 3.13 ± 0.02%), while it decreased by 9.12% from 3.18 ± 0.04% to 2.89 ± 0.02% for the NFM-MFC. The MCEF separator was with less biofouling than the NFM separator over 60 days' operation, which might be the reason for the more table long-term performance of the MCEF-MFC. The results demonstrated that MCEF was feasible as a separator to set up good-performing and cost-effective air-diffusion cathode MFC.

Relative enhanced diffusivity: noise sensitivity, protocol optimization, and the relation to intravoxel incoherent motion.

PubMed

While, Peter T; Teruel, Jose R; Vidić, Igor; Bathen, Tone F; Goa, Pål Erik

2018-06-01

To explore the relationship between relative enhanced diffusivity (RED) and intravoxel incoherent motion (IVIM), as well as the impact of noise and the choice of intermediate diffusion weighting (b value) on the RED parameter. A mathematical derivation was performed to cast RED in terms of the IVIM parameters. Noise analysis and b value optimization was conducted by using Monte Carlo calculations to generate diffusion-weighted imaging data appropriate to breast and liver tissue at three different signal-to-noise ratios. RED was shown to be approximately linearly proportional to the IVIM parameter f, inversely proportional to D and to follow an inverse exponential decay with respect to D*. The choice of intermediate b value was shown to be important in minimizing the impact of noise on RED and in maximizing its discriminatory power. RED was shown to be essentially a reparameterization of the IVIM estimates for f and D obtained with three b values. RED imaging in the breast and liver should be performed with intermediate b values of 100 and 50 s/mm 2 , respectively. Future clinical studies involving RED should also estimate the IVIM parameters f and D using three b values for comparison.

On the Chemical Mixing Induced by Internal Gravity Waves

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

Rogers, T. M.; McElwaine, J. N.

Detailed modeling of stellar evolution requires a better understanding of the (magneto)hydrodynamic processes that mix chemical elements and transport angular momentum. Understanding these processes is crucial if we are to accurately interpret observations of chemical abundance anomalies, surface rotation measurements, and asteroseismic data. Here, we use two-dimensional hydrodynamic simulations of the generation and propagation of internal gravity waves in an intermediate-mass star to measure the chemical mixing induced by these waves. We show that such mixing can generally be treated as a diffusive process. We then show that the local diffusion coefficient does not depend on the local fluid velocity,more » but rather on the wave amplitude. We then use these findings to provide a simple parameterization for this diffusion, which can be incorporated into stellar evolution codes and tested against observations.« less

Age-related differences in reliance behavior attributable to costs within a human-decision aid system.

PubMed

Ezer, Neta; Fisk, Arthur D; Rogers, Wendy A

2008-12-01

An empirical investigation was done to determine if there are age-related differences attributable to costs in reliance on a decision aid. Costs of reliance on a decision aid may affect reliance on the aid. Older and younger adults may not perceive and respond to a dynamic cost structure equally or objectively. Sixteen older adults (65-74 years) and 16 younger adults (18-28 years) performed a counting task with an imperfect decision aid. Two types of costs were manipulated: (a) cost of error (CoE) and (b) cost of verification (CoV). The percentage of trials in which participants agreed with the decision aid and did not perform the task manually was recorded as reliance. Participants decreased their reliance as the CoE increased and increased their reliance with a lower CoV; however, they tended to underrely on the decision aid. Younger adults tended to change their reliance behavior more than older adults did with the changing cost structure. Older and younger adults appear to interpret costs differently, with older adults being less responsive to changes in costs. Older adults may have been less able to monitor the changing costs and hence not adapt to them as well as younger adults. Designers of decision aids should consider explicitly stating costs associated with reliance on the aid, as individuals may differ in how they interpret and respond to changing costs.

Detection of polyomavirus simian virus 40 tumor antigen DNA in AIDS-related systemic non-Hodgkin lymphoma

NASA Technical Reports Server (NTRS)

Vilchez, Regis A.; Lednicky, John A.; Halvorson, Steven J.; White, Zoe S.; Kozinetz, Claudia A.; Butel, Janet S.

2002-01-01

Systemic non-Hodgkin lymphoma (S-NHL) is a common malignancy during HIV infection, and it is hypothesized that infectious agents may be involved in the etiology. Epstein-Barr virus DNA is found in <40% of patients with AIDS-related S-NHL, suggesting that other oncogenic viruses, such as polyomaviruses, may play a role in pathogenesis. We analyzed AIDS-related S-NHL samples, NHL samples from HIV-negative patients, peripheral blood leukocytes from HIV-infected and -uninfected patients without NHL, and lymph nodes without tumors from HIV-infected patients. Specimens were examined by polymerase chain reaction analysis with use of primers specific for an N-terminal region of the oncoprotein large tumor antigen ( T-ag ) gene conserved among all three polyomaviruses (simian virus 40 [SV40], JC virus, and BK virus). Polyomavirus T-ag DNA sequences, proven to be SV40-specific, were detected more frequently in AIDS-related S-NHL samples (6 of 26) than in peripheral blood leukocytes from HIV-infected patients (6 of 26 vs. 0 of 69; p =.0001), NHL samples from HIV-negative patients (6 of 26 vs. 0 of 10; p =.09), or lymph nodes (6 of 26 vs. 0 of 7; p =.16). Sequences of C-terminal T-ag DNA from SV40 were amplified from two AIDS-related S-NHL samples. Epstein-Barr virus DNA sequences were detected in 38% (10 of 26) AIDS-related S-NHL samples, 50% (5 of 10) HIV-negative S-NHL samples, and 57% (4 of 7) lymph nodes. None of the S-NHL samples were positive for both Epstein-Barr virus DNA and SV40 DNA. Further studies of the possible role of SV40 in the pathogenesis of S-NHL are warranted.

Fludarabine and Total-Body Irradiation Followed By Donor Stem Cell Transplant and Cyclosporine and Mycophenolate Mofetil in Treating HIV-Positive Patients With or Without Cancer

ClinicalTrials.gov

2017-04-17

Accelerated Phase Chronic Myelogenous Leukemia; Acute Undifferentiated Leukemia; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Adult Grade III Lymphomatoid Granulomatosis; Adult Nasal Type Extranodal NK/T-cell Lymphoma; Aggressive NK-cell Leukemia; AIDS-related Diffuse Large Cell Lymphoma; AIDS-related Diffuse Mixed Cell Lymphoma; AIDS-related Diffuse Small Cleaved Cell Lymphoma; AIDS-related Immunoblastic Large Cell Lymphoma; AIDS-related Lymphoblastic Lymphoma; AIDS-related Peripheral/Systemic Lymphoma; AIDS-related Primary CNS Lymphoma; AIDS-related Small Noncleaved Cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Blastic Phase Chronic Myelogenous Leukemia; Childhood Acute Lymphoblastic Leukemia in Remission; Childhood Acute Myeloid Leukemia in Remission; Childhood Burkitt Lymphoma; Childhood Chronic Myelogenous Leukemia; Childhood Diffuse Large Cell Lymphoma; Childhood Grade III Lymphomatoid Granulomatosis; Childhood Immunoblastic Large Cell Lymphoma; Childhood Myelodysplastic Syndromes; Childhood Nasal Type Extranodal NK/T-cell Lymphoma; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; Contiguous Stage II Adult Burkitt Lymphoma; Contiguous Stage II Adult Diffuse Large Cell Lymphoma; Contiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Contiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Contiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Contiguous Stage II Adult Lymphoblastic Lymphoma; Contiguous Stage II Grade 1 Follicular Lymphoma; Contiguous Stage II Grade 2

Mixed Polyanion Glass Cathodes: Mixed Alkali Effect

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

Kercher, A. K.; Chapel, A. S.; Kolopus, J. A.

2017-01-01

In lithium-ion batteries, mixed polyanion glass cathodes have demonstrated high capacities (200-500 mAh/g) by undergoing conversion and intercalation reactions. Mixed polyanion glasses typically have the same fundamental issues as other conversion cathodes, i.e.: large hysteresis, capacity fade, and 1st-cycle irreversible loss. A key advantage of glass cathodes is the ability to tailor their composition to optimize the desired physical properties and electrochemical performance. The strong dependence of glass physical properties (e.g., ionic diffusivity, electrical conductivity, and chemical durability) on the composition of alkali mixtures in a glass is well known and has been named the mixed alkali effect. The mixedmore » alkali effect on battery electrochemical properties is reported here for the first time. Depending on glass composition, the mixed alkali effect is shown to improve capacity retention during cycling (from 39% to 50% after 50 cycle test), to reduce the 1st-cycle irreversible loss (from 41% to 22%), and improve the high power (500 mA/g) capacity (from 50% to 67% of slow discharge capacity).« less

Modeling Bimolecular Reactive Transport With Mixing-Limitation: Theory and Application to Column Experiments

NASA Astrophysics Data System (ADS)

Ginn, T. R.

2018-01-01

The challenge of determining mixing extent of solutions undergoing advective-dispersive-diffusive transport is well known. In particular, reaction extent between displacing and displaced solutes depends on mixing at the pore scale, that is, generally smaller than continuum scale quantification that relies on dispersive fluxes. Here a novel mobile-mobile mass transfer approach is developed to distinguish diffusive mixing from dispersive spreading in one-dimensional transport involving small-scale velocity variations with some correlation, such as occurs in hydrodynamic dispersion, in which short-range ballistic transports give rise to dispersed but not mixed segregation zones, termed here ballisticules. When considering transport of a single solution, this approach distinguishes self-diffusive mixing from spreading, and in the case of displacement of one solution by another, each containing a participant reactant of an irreversible bimolecular reaction, this results in time-delayed diffusive mixing of reactants. The approach generates models for both kinetically controlled and equilibrium irreversible reaction cases, while honoring independently measured reaction rates and dispersivities. The mathematical solution for the equilibrium case is a simple analytical expression. The approach is applied to published experimental data on bimolecular reactions for homogeneous porous media under postasymptotic dispersive conditions with good results.

Women's voices: attitudes and behaviors of female Ghanaian sex workers regarding HIV prevention and AIDS-related stigma.

PubMed

Raingruber, Bonnie; Uwazie, Ernest; Bowie, Sylvester

2010-08-01

Attitudes and behaviors of sex workers have a pivotal influence on the spread of AIDS. A qualitative descriptive study was undertaken to elicit Ghanaian female sex workers' perspectives regarding effective methods of HIV prevention, sources of AIDS-related stigma, and challenges associated with sex work. Women described that: (1) sex work is hard; (2) they felt God would protect their health; (3) staying safe is both a gift and a priority; (4) sex work allows for autonomy; and (5) AIDS-related stigma is very real. To design effective prevention programs it is necessary to consider the culture and perspectives of those who will be served.

Asbestos-related diffuse pleural thickening.

PubMed

Fujimoto, Nobukazu; Kato, Katsuya; Usami, Ikuji; Sakai, Fumikazu; Tokuyama, Takeshi; Hayashi, Seiji; Miyamoto, Kenji; Kishimoto, Takumi

2014-01-01

The clinical features of asbestos-related diffuse pleural thickening (DPT) remain unclear. To clarify the association between radiological findings of DPT and respiratory function. Medical data from patients with asbestos-related DPT were collected, including their history of occupational or neighborhood asbestos exposure, initial symptoms, modified Medical Research Council dyspnea grade, smoking history, radiological findings, and respiratory function test results. There were 106 DPT patients between 2005 and 2010 [i.e. 103 men (97.2%) and 3 women (2.8%)]. The median age at diagnosis was 69 years (range 46-88). Patient occupations related to asbestos exposure included: asbestos product manufacturing (n = 17); the shipbuilding industry (n = 14); the construction industry (n = 13); heat insulation work (n = 12); plumbing, asbestos spraying, and electrical work (n = 7 each), and transportation and demolition work (n = 4 each). The median duration of asbestos exposure was 25 years (range 2-54), and the median latency period before the onset of DPT was 46 years (range 25-66). Involvement of the costophrenic angle (CPA) was also negatively correlated with the percent vital capacity (%VC; r = -0.448, p < 0.01). Pleural thickness and the craniocaudal and horizontal extension of pleural thickening, as determined by chest computed tomography (CT), were also negatively correlated with %VC (r = -0.226, p < 0.05; r = -0.409, p < 0.01, and r = -0.408, p < 0.01, respectively). DPT develops after a long latency period following occupational asbestos exposure and causes marked respiratory dysfunction. The extension of DPT should be evaluated by chest CT, and chest X-ray would be important for the evaluation of the involvement of the CPA.

Linear response theory and transient fluctuation relations for diffusion processes: a backward point of view

NASA Astrophysics Data System (ADS)

Liu, Fei; Tong, Huan; Ma, Rui; Ou-Yang, Zhong-can

2010-12-01

A formal apparatus is developed to unify derivations of the linear response theory and a variety of transient fluctuation relations for continuous diffusion processes from a backward point of view. The basis is a perturbed Kolmogorov backward equation and the path integral representation of its solution. We find that these exact transient relations could be interpreted as a consequence of a generalized Chapman-Kolmogorov equation, which intrinsically arises from the Markovian characteristic of diffusion processes.

FBI fingerprint identification automation study. AIDS 3 evaluation report. Volume 4: Economic feasibility

NASA Technical Reports Server (NTRS)

Mulhall, B. D. L.

1980-01-01

The results of the economic analysis of the AIDS 3 system design are presented. AIDS 3 evaluated a set of economic feasibility measures including life cycle cost, implementation cost, annual operating expenditures and annual capital expenditures. The economic feasibility of AIDS 3 was determined by comparing the evaluated measures with the same measures, where applicable, evaluated for the current system. A set of future work load scenarios was constructed using JPL's environmental evaluation study of the fingerprint identification system. AIDS 3 and the current system were evaluated for each of the economic feasibility measures for each of the work load scenarios. They were compared for a set of performance measures, including response time and accuracy, and for a set of cost/benefit ratios, including cost per transaction and cost per technical search. Benefit measures related to the economic feasibility of the system are also presented, including the required number of employees and the required employee skill mix.

Ergotism related to a single dose of ergotamine tartrate in an AIDS patient treated with ritonavir

PubMed Central

Blanche, P; Rigolet, A; Gombert, B; Ginsburg, C; Salmon, D; Sicard, D

1999-01-01

We report a rare case of ergotism related to a single dose of ergotamine tartrate in a man with AIDS being treated with ritonavir. He was treated with a prostacyclin analogue and made a complete recovery.


Keywords: ergotism; ergotamine tartrate; AIDS; ritonavir; adverse drug reaction; HIV infection PMID:10616689

Genetic Testing Plus Irinotecan in Treating Patients With Solid Tumors or Lymphoma

ClinicalTrials.gov

2013-01-23

AIDS-related Peripheral/Systemic Lymphoma; AIDS-related Primary CNS Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Intraocular Lymphoma; Nodal Marginal Zone B-cell Lymphoma; Primary Central Nervous System Non-Hodgkin Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Adult T-cell Leukemia/Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent Small Lymphocytic Lymphoma; Small Intestine Lymphoma; Splenic Marginal Zone Lymphoma; Stage III Adult Burkitt Lymphoma; Stage III Adult Diffuse Large Cell Lymphoma; Stage III Adult Diffuse Mixed Cell Lymphoma; Stage III Adult Diffuse Small Cleaved Cell Lymphoma; Stage III Adult Hodgkin Lymphoma; Stage III Adult Immunoblastic Large Cell Lymphoma; Stage III Adult Lymphoblastic Lymphoma; Stage III Adult T-cell Leukemia/Lymphoma; Stage III Cutaneous T-cell Non-Hodgkin Lymphoma; Stage III Grade 1 Follicular Lymphoma; Stage III Grade 2 Follicular Lymphoma; Stage III Grade 3 Follicular Lymphoma; Stage III Mantle Cell Lymphoma; Stage III Marginal Zone Lymphoma; Stage III Mycosis Fungoides/Sezary Syndrome; Stage III Small Lymphocytic Lymphoma; Stage IV Adult Burkitt Lymphoma; Stage IV Adult Diffuse Large Cell Lymphoma; Stage IV Adult Diffuse Mixed Cell Lymphoma; Stage IV Adult Diffuse Small Cleaved Cell Lymphoma; Stage IV Adult Hodgkin Lymphoma; Stage IV Adult Immunoblastic Large Cell Lymphoma; Stage IV Adult Lymphoblastic

Notes on hyperscaling violating Lifshitz and shear diffusion

NASA Astrophysics Data System (ADS)

Kolekar, Kedar S.; Mukherjee, Debangshu; Narayan, K.

2017-07-01

We explore in greater detail our investigations of shear diffusion in hyperscaling violating Lifshitz theories in Phys. Lett. B 760, 86 (2016), 10.1016/j.physletb.2016.06.046. This adapts and generalizes the membrane-paradigm-like analysis of Kovtun, Son, and Starinets for shear gravitational perturbations in the near horizon region given certain self-consistent approximations, leading to the shear diffusion constant on an appropriately defined stretched horizon. In theories containing a gauge field, some of the metric perturbations mix with some of the gauge field perturbations and the above analysis is somewhat more complicated. We find a similar near-horizon analysis can be obtained in terms of new field variables involving a linear combination of the metric and the gauge field perturbation resulting in a corresponding diffusion equation. Thereby as before, for theories with Lifshitz and hyperscaling violating exponents z , θ satisfying z <4 -θ in four bulk dimensions, our analysis here results in a similar expression for the shear diffusion constant with power-law scaling with temperature suggesting universal behavior in relation to the viscosity bound. For z =4 -θ , we find logarithmic behavior.

Quantitative confirmation of diffusion-limited oxidation theories

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

Gillen, K.T.; Clough, R.L.

1990-01-01

Diffusion-limited (heterogeneous) oxidation effects are often important for studies of polymer degradation. Such effects are common in polymers subjected to ionizing radiation at relatively high dose rate. To better understand the underlying oxidation processes and to aid in the planning of accelerated aging studies, it would be desirable to be able to monitor and quantitatively understand these effects. In this paper, we briefly review a theoretical diffusion approach which derives model profiles for oxygen surrounded sheets of material by combining oxygen permeation rates with kinetically based oxygen consumption expressions. The theory leads to a simple governing expression involving the oxygenmore » consumption and permeation rates together with two model parameters {alpha} and {beta}. To test the theory, gamma-initiated oxidation of a sheet of commercially formulated EPDM rubber was performed under conditions which led to diffusion-limited oxidation. Profile shapes from the theoretical treatments are shown to accurately fit experimentally derived oxidation profiles. In addition, direct measurements on the same EPDM material of the oxygen consumption and permeation rates, together with values of {alpha} and {beta} derived from the fitting procedure, allow us to quantitatively confirm for the first time the governing theoretical relationship. 17 refs., 3 figs.« less

Impact of Parental HIV/AIDS on Children’s Psychological Well-Being: A Systematic Review of Global Literature

PubMed Central

Chi, Peilian; Li, Xiaoming

2012-01-01

This review examines the global literature regarding the impact of parental HIV/AIDS on children’s psychological well-being. Fifty one articles reporting quantitative data from a total of 30 studies were retrieved and reviewed. Findings were mixed but tended to show that AIDS orphans and vulnerable children had poorer psychological well-being in comparison with children from HIV-free families or children orphaned by other causes. Limited longitudinal studies suggested a negative effect of parental HIV on children’s psychological well-being in an early stage of parental HIV-related illness and such effects persisted through the course of parental illness and after parental death. HIV-related stressful life events, stigma, and poverty were risk factors that might aggravate the negative impact of parental HIV/AIDS on children. Individual coping skills, trusting relationship with caregivers and social support were suggested to protect children against the negative effects of parental HIV/AIDS. This review underlines the vulnerability of children affected by HIV/AIDS. Culturally and developmentally appropriate evidence-based interventions are urgently needed to promote the psychological well-being of children affected by HIV/AIDS. PMID:22972606

Hippocampus age-related microstructural changes in schizophrenia: a case-control mean diffusivity study.

PubMed

Chiapponi, Chiara; Piras, Fabrizio; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco

2014-08-01

Macrostructural-volumetric abnormalities of the hippocampus have been described in schizophrenia. Here, we characterized age-related changes of hippocampal mean diffusivity as an index of microstructural damage by carrying out a neuroimaging study in 85 patients with a DSM-IV-TR diagnosis of schizophrenia and 85 age- and gender-matched healthy controls. We performed analyses of covariance, with diagnosis as fixed factor, mean diffusivity as dependent variable and age as covariate. Patients showed an early increase in mean diffusivity in the right and left hippocampus that increased with age. Thus, microstructural hippocampal changes associated with schizophrenia cannot be confined to a specific time window. Copyright © 2014 Elsevier B.V. All rights reserved.

A prospective microstructure imaging study in mixed-martial artists using geometric measures and diffusion tensor imaging: methods and findings

PubMed Central

Mayer, Andrew R.; Ling, Josef M.; Dodd, Andrew B.; Meier, Timothy B.; Hanlon, Faith M.; Klimaj, Stefan D.

2018-01-01

Although diffusion magnetic resonance imaging (dMRI) has been widely used to characterize the effects of repetitive mild traumatic brain injury (rmTBI), to date no studies have investigated how novel geometric models of microstructure relate to more typical diffusion tensor imaging (DTI) sequences. Moreover, few studies have evaluated the sensitivity of different registration pipelines (non-linear, linear and tract-based spatial statistics) for detecting dMRI abnormalities in clinical populations. Results from single-subject analyses in healthy controls (HC) indicated a strong negative relationship between fractional anisotropy (FA) and orientation dispersion index (ODI) in both white and gray matter. Equally important, only moderate relationships existed between all other estimates of free/intracellular water volume fractions and more traditional DTI metrics (FA, mean, axial and radial diffusivity). These findings suggest that geometric measures provide differential information about the cellular microstructure relative to traditional DTI measures. Results also suggest greater sensitivity for non-linear registration pipelines that maximize the anatomical information available in T1-weighted images. Clinically, rmTBI resulted in a pattern of decreased FA and increased ODI, largely overlapping in space, in conjunction with increased intracellular and free water fractions, highlighting the potential role of edema following repeated head trauma. In summary, current results suggest that geometric models of diffusion can provide relatively unique information regarding potential mechanisms of pathology that contribute to long-term neurological damage. PMID:27071950

A prospective microstructure imaging study in mixed-martial artists using geometric measures and diffusion tensor imaging: methods and findings.

PubMed

Mayer, Andrew R; Ling, Josef M; Dodd, Andrew B; Meier, Timothy B; Hanlon, Faith M; Klimaj, Stefan D

2017-06-01

Although diffusion magnetic resonance imaging (dMRI) has been widely used to characterize the effects of repetitive mild traumatic brain injury (rmTBI), to date no studies have investigated how novel geometric models of microstructure relate to more typical diffusion tensor imaging (DTI) sequences. Moreover, few studies have evaluated the sensitivity of different registration pipelines (non-linear, linear and tract-based spatial statistics) for detecting dMRI abnormalities in clinical populations. Results from single-subject analyses in healthy controls (HC) indicated a strong negative relationship between fractional anisotropy (FA) and orientation dispersion index (ODI) in both white and gray matter. Equally important, only moderate relationships existed between all other estimates of free/intracellular water volume fractions and more traditional DTI metrics (FA, mean, axial and radial diffusivity). These findings suggest that geometric measures provide differential information about the cellular microstructure relative to traditional DTI measures. Results also suggest greater sensitivity for non-linear registration pipelines that maximize the anatomical information available in T 1 -weighted images. Clinically, rmTBI resulted in a pattern of decreased FA and increased ODI, largely overlapping in space, in conjunction with increased intracellular and free water fractions, highlighting the potential role of edema following repeated head trauma. In summary, current results suggest that geometric models of diffusion can provide relatively unique information regarding potential mechanisms of pathology that contribute to long-term neurological damage.

Microfluidic Mixing: A Review

PubMed Central

Lee, Chia-Yen; Chang, Chin-Lung; Wang, Yao-Nan; Fu, Lung-Ming

2011-01-01

The aim of microfluidic mixing is to achieve a thorough and rapid mixing of multiple samples in microscale devices. In such devices, sample mixing is essentially achieved by enhancing the diffusion effect between the different species flows. Broadly speaking, microfluidic mixing schemes can be categorized as either “active”, where an external energy force is applied to perturb the sample species, or “passive”, where the contact area and contact time of the species samples are increased through specially-designed microchannel configurations. Many mixers have been proposed to facilitate this task over the past 10 years. Accordingly, this paper commences by providing a high level overview of the field of microfluidic mixing devices before describing some of the more significant proposals for active and passive mixers. PMID:21686184

Probing the Evaporation Dynamics of Mixed SOA/Squalane Particles Using Size-Resolved Composition and Single-Particle Measurements.

PubMed

Robinson, Ellis Shipley; Saleh, Rawad; Donahue, Neil M

2015-08-18

An analysis of the formation and evaporation of mixed-particles containing squalane (a surrogate for hydrophobic primary organic aerosol, POA) and secondary organic aerosol (SOA) is presented. In these experiments, one material (D62-squalane or SOA from α-pinene + O3) was prepared first to serve as surface area for condensation of the other, forming the mixed-particles. The mixed-particles were then subjected to a heating-ramp from 22 to 44 °C. We were able to determine that (1) almost all of the SOA mass is comprised of material less volatile than D62-squalane; (2) AMS collection efficiency in these mixed-particle systems can be parametrized as a function of the relative mass fraction of the components; and (3) the vast majority of D62-squalane is able to evaporate from the mixed particles, and does so on the same time scale regardless of the order of preparation. We also performed two-population mixing experiments to directly test whether D62-squalane and SOA from α-pinene + O3 form a single solution or two separate phases. We find that these two OA types are immiscible, which informs our inference of the morphology of the mixed-particles. If the morphology is core-shell and dictated by the order of preparation, these data indicate that squalane is able to diffuse relatively quickly through the SOA shell, implying that there are no major diffusion limitations.

Enhanced reaction kinetics and reactive mixing scale dynamics in mixing fronts under shear flow for arbitrary Damköhler numbers

NASA Astrophysics Data System (ADS)

Bandopadhyay, Aditya; Le Borgne, Tanguy; Méheust, Yves; Dentz, Marco

2017-02-01

Mixing fronts, where fluids of different chemical compositions mix with each other, are known to represent hotspots of chemical reaction in hydrological systems. These fronts are typically subjected to velocity gradients, ranging from the pore scale due to no slip boundary conditions at fluid solid interfaces, to the catchment scale due to permeability variations and complex geometry of the Darcy velocity streamlines. A common trait of these processes is that the mixing interface is strained by shear. Depending on the Péclet number Pe , which represents the ratio of the characteristic diffusion time to the characteristic shear time, and the Damköhler number Da , which represents the ratio of the characteristic diffusion time to the characteristic reaction time, the local reaction rates can be strongly impacted by the dynamics of the mixing interface. So far, this impact has been characterized mostly either in kinetics-limited or in mixing-limited conditions, that is, for either low or high Da. Here the coupling of shear flow and chemical reactivity is investigated for arbitrary Damköhler numbers, for a bimolecular reaction and an initial interface with separated reactants. Approximate analytical expressions for the global production rate and reactive mixing scale are derived based on a reactive lamella approach that allows for a general coupling between stretching enhanced mixing and chemical reactions. While for Pe < Da , reaction kinetics and stretching effects are decoupled, a scenario which we name "weak stretching", for Pe > Da , we uncover a "strong stretching" scenario where new scaling laws emerge from the interplay between reaction kinetics, diffusion, and stretching. The analytical results are validated against numerical simulations. These findings shed light on the effect of flow heterogeneity on the enhancement of chemical reaction and the creation of spatially localized hotspots of reactivity for a broad range of systems ranging from kinetic limited

The Analytical Limits of Modeling Short Diffusion Timescales

NASA Astrophysics Data System (ADS)

Bradshaw, R. W.; Kent, A. J.

2016-12-01

Chemical and isotopic zoning in minerals is widely used to constrain the timescales of magmatic processes such as magma mixing and crystal residence, etc. via diffusion modeling. Forward modeling of diffusion relies on fitting diffusion profiles to measured compositional gradients. However, an individual measurement is essentially an average composition for a segment of the gradient defined by the spatial resolution of the analysis. Thus there is the potential for the analytical spatial resolution to limit the timescales that can be determined for an element of given diffusivity, particularly where the scale of the gradient approaches that of the measurement. Here we use a probabilistic modeling approach to investigate the effect of analytical spatial resolution on estimated timescales from diffusion modeling. Our method investigates how accurately the age of a synthetic diffusion profile can be obtained by modeling an "unknown" profile derived from discrete sampling of the synthetic compositional gradient at a given spatial resolution. We also include the effects of analytical uncertainty and the position of measurements relative to the diffusion gradient. We apply this method to the spatial resolutions of common microanalytical techniques (LA-ICP-MS, SIMS, EMP, NanoSIMS). Our results confirm that for a given diffusivity, higher spatial resolution gives access to shorter timescales, and that each analytical spacing has a minimum timescale, below which it overestimates the timescale. For example, for Ba diffusion in plagioclase at 750 °C timescales are accurate (within 20%) above 10, 100, 2,600, and 71,000 years at 0.3, 1, 5, and 25 mm spatial resolution, respectively. For Sr diffusion in plagioclase at 750 °C, timescales are accurate above 0.02, 0.2, 4, and 120 years at the same spatial resolutions. Our results highlight the importance of selecting appropriate analytical techniques to estimate accurate diffusion-based timescales.

Computer-aided engineering of semiconductor integrated circuits

NASA Astrophysics Data System (ADS)

Meindl, J. D.; Dutton, R. W.; Gibbons, J. F.; Helms, C. R.; Plummer, J. D.; Tiller, W. A.; Ho, C. P.; Saraswat, K. C.; Deal, B. E.; Kamins, T. I.

1980-07-01

Economical procurement of small quantities of high performance custom integrated circuits for military systems is impeded by inadequate process, device and circuit models that handicap low cost computer aided design. The principal objective of this program is to formulate physical models of fabrication processes, devices and circuits to allow total computer-aided design of custom large-scale integrated circuits. The basic areas under investigation are (1) thermal oxidation, (2) ion implantation and diffusion, (3) chemical vapor deposition of silicon and refractory metal silicides, (4) device simulation and analytic measurements. This report discusses the fourth year of the program.

Prediction of the blowout of jet diffusion flames in a coflowing stream of air

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

Karbasi, M.; Wierzba, I.

1995-12-31

The blowout limits of a lifted diffusion flame in a coflowing stream of air are estimated using a simple model for extinction, for a range of fuels, jet diameters and co-flowing stream velocities. The proposed model uses a parameter which relates to the ratio of a time associated with the mixing processes in a turbulent jet to a characteristic chemical time. The Kolmogorov microscale of time is used as time scale in this model. It is shown that turbulent diffusion flames are quenched by excessive turbulence for a critical value of this parameter. The predicted blowout velocity of diffusion flamesmore » obtained using this model is in good agreement with the available experimental data.« less

The "Spread" of Merit-Based College Aid: Politics, Policy Consortia, and Interstate Competition

ERIC Educational Resources Information Center

Cohen-Vogel, Lora; Ingle, William Kyle; Levine, Amy Albee; Spence, Matthew

2008-01-01

Many political scientists maintain that public policies diffuse across states and that proximate states, in particular, influence one another's policy activities. Using state-funded merit aid for college as its case, this article takes a new approach to the study of the diffusion phenomenon, leaving behind conventional techniques used by…

The Burden of Exposure–Related Diffuse Lung Disease

PubMed Central

Goldyn, Sheryl R.; Condos, Rany; Rom, William N.

2013-01-01

Estimating the burden of exposure-related diffuse lung disease in terms of health effects and economic burden remains challenging. Labor statistics are inadequate to define the scope of the problem, and few studies have analyzed the prevalence of exposure-related illnesses and the subsequent health care cost. Well-defined exposures, such as those associated with coal mines, asbestos mines, and stonecutting, have led to more accurate assessment of prevalence and cost. As governmental regulation of workplace exposure has increased, the prevalence of diseases such as silicosis and coal workers’ pneumoconiosis has diminished. However, the health and economic effects of diseases with long latency periods, such as asbestosis and mesothelioma, continue to increase in the short term. Newer exposures, such as those related to air pollution, nylon flock, and the World Trade Center collapse, have added to these costs. As a result, estimates of cost for occupational diseases, including respiratory illnesses, exceed $26 billion annually, and the true economic burden is likely much higher. PMID:19221957

First impressions last… A survey of knowledge of first aid in burn-related injuries amongst hospital workers.

PubMed

Tay, Poi Hoon; Pinder, Richard; Coulson, Samuel; Rawlins, Jeremy

2013-03-01

The administration of first aid in burns has been shown to have a significant influence on the ultimate severity of the burn. We wanted to assess in-hospital healthcare (HCW), and non-healthcare workers' (nHCW) knowledge of first aid in burns. A purpose-designed questionnaire, including information about previous attendance at a first aid course and four clinical scenarios of burns, was distributed to HCWs in the local hospitals and non-medical students in the Universities of Leeds and Sheffield. 697 questionnaires were completed - 397 (57%) from HCW and 300 (43%) from nHCW. 59% of HCW had attended a first aid course, 68% of these courses included teaching on first aid in burns. HCW who had completed a first aid course generally did better than those who had not. Only 16% of HCW achieved correct answers in all questions compared to 30% nHCW. We show that the knowledge of first aid in burns is relatively poor amongst HCW and that attendance at a burns first aid course improves knowledge (although perhaps not as much as one might hope). We recommend that the burns content of first aid courses be reviewed, and that there is a requirement for ALL hospital healthcare workers to undertake a first aid course, which includes appropriate burns first aid. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

Religion and HIV/AIDS stigma: Implications for health professionals in Puerto Rico

PubMed Central

Varas-Díaz, N.; Neilands, T.B.; Malavé Rivera, S.; Betancourt, E.

2009-01-01

HIV/AIDS stigma continues to be a barrier for prevention efforts. Its detrimental effects have been documented among people living with HIV/AIDS and encompass loss of social support and depression. When it is manifested by health professionals, it can lead to suboptimal services. Although strides have been made to document the effects of HIV/AIDS stigma, much needs to be done in order to understand the structural factors that can foster it. Such is the case of religion’s role on HIV/AIDS stigma in Puerto Rico. The Caribbean Island has a Judeo-Christian based culture due to years of Spanish colonisation. This religious influence continued under Protestantism as part of the Island’s integration as a non-incorporated territory of the USA. The main objective of this study was to explore the role of religion in HIV/AIDS stigma manifested by Puerto Rican health professionals in practice and in training. Through a mixed method approach, 501 health professionals completed qualitative interviews (n=80) and self-administered questionnaires (n=421). Results show that religion plays some role in conceptualisations of health and illness among participants in the study. Furthermore, the importance placed on religion and participation in such activities was related to higher levels of HIV/AIDS stigma. PMID:20087809

Cosmic ray diffusion: Report of the Workshop in Cosmic Ray Diffusion Theory

NASA Technical Reports Server (NTRS)

Birmingham, T. J.; Jones, F. C.

1975-01-01

A workshop in cosmic ray diffusion theory was held at Goddard Space Flight Center on May 16-17, 1974. Topics discussed and summarized are: (1) cosmic ray measurements as related to diffusion theory; (2) quasi-linear theory, nonlinear theory, and computer simulation of cosmic ray pitch-angle diffusion; and (3) magnetic field fluctuation measurements as related to diffusion theory.

Three-dimensional Diffusive Strip Method

NASA Astrophysics Data System (ADS)

Martinez-Ruiz, Daniel; Meunier, Patrice; Duchemin, Laurent; Villermaux, Emmanuel

2016-11-01

The Diffusive Strip Method (DSM) is a near-exact numerical method developed for mixing computations at large Péclet number in two-dimensions. The method consists in following stretched material lines to compute a-posteriori the resulting scalar field is extended here to three-dimensional flows, following surfaces. We describe its 3D peculiarities, and show how it applies to a simple Taylor-Couette configuration with non-rotating boundary conditions at the top end, bottom and outer cylinder. This flow produces an elaborate, although controlled, steady 3D flow which relies on the Ekman pumping arising from the rotation of the inner cylinder is both studied experimentally, and numerically modeled. A recurrent two-cells structure appears formed by stream tubes shaped as nested tori. A scalar blob in the flow experiences a Lagrangian oscillating dynamics with stretchings and compressions, driving the mixing process, and yielding both rapidly-mixed and nearly pure-diffusive regions. A triangulated-surface method is developed to calculate the blob elongation and scalar concentration PDFs through a single variable computation along the advected blob surface, capturing the rich evolution observed in the experiments.

Diffusion in coastal and harbour zones, effects of Waves,Wind and Currents

NASA Astrophysics Data System (ADS)

Diez, M.; Redondo, J. M.

2009-04-01

As there are multiple processes at different scales that produce turbulent mixing in the ocean, thus giving a large variation of horizontal eddy diffusivities, we use a direct method to evaluate the influence of different ambient parameters such as wave height and wind on coastal dispersion. Measurements of the diffusivity are made by digital processing of images taken from from video recordings of the sea surface near the coast. The use of image analysis allows to estimate both spatial and temporal characteristics of wave fields, surface circulation and mixing in the surf zone, near Wave breakers and inside Harbours. The study of near-shore dispersion [1], with the added complexity of the interaction between wave fields, longshore currents, turbulence and beach morphology, needs detailed measurements of simple mixing processes to compare the respective influences of forcings at different scales. The measurements include simultaneous time series of waves, currents, wind velocities from the studied area. Cuantitative information from the video images is accomplished using the DigImage video processing system [3], and a frame grabber. The video may be controlled by the computer, allowing, remote control of the processing. Spectral analysis on the images has also used n order to estimate dominant wave periods as well as the dispersion relations of dominant instabilities. The measurements presented here consist mostly on the comarison of difussion coeficients measured by evaluating the spread of blobs of dye (milk) as well as by measuring the separation between different buoys released at the same time. We have used a techniques, developed by Bahia(1997), Diez(1998) and Bezerra(2000)[1-3] to study turbulent diffusion by means of digital processing of images taken from remote sensing and video recordings of the sea surface. The use of image analysis allows to measure variations of several decades in horizontal diffusivity values, the comparison of the diffusivities

A novel family of DG methods for diffusion problems

NASA Astrophysics Data System (ADS)

Johnson, Philip; Johnsen, Eric

2017-11-01

We describe and demonstrate a novel family of numerical schemes for handling elliptic/parabolic PDE behavior within the discontinuous Galerkin (DG) framework. Starting from the mixed-form approach commonly applied for handling diffusion (examples include Local DG and BR2), the new schemes apply the Recovery concept of Van Leer to handle cell interface terms. By applying recovery within the mixed-form approach, we have designed multiple schemes that show better accuracy than other mixed-form approaches while being more flexible and easier to implement than the Recovery DG schemes of Van Leer. While typical mixed-form approaches converge at rate 2p in the cell-average or functional error norms (where p is the order of the solution polynomial), many of our approaches achieve order 2p +2 convergence. In this talk, we will describe multiple schemes, including both compact and non-compact implementations; the compact approaches use only interface-connected neighbors to form the residual for each element, while the non-compact approaches add one extra layer to the stencil. In addition to testing the schemes on purely parabolic PDE problems, we apply them to handle the diffusive flux terms in advection-diffusion systems, such as the compressible Navier-Stokes equations.

Optimal Control of Evolution Mixed Variational Inclusions

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

Alduncin, Gonzalo, E-mail: alduncin@geofisica.unam.mx

2013-12-15

Optimal control problems of primal and dual evolution mixed variational inclusions, in reflexive Banach spaces, are studied. The solvability analysis of the mixed state systems is established via duality principles. The optimality analysis is performed in terms of perturbation conjugate duality methods, and proximation penalty-duality algorithms to mixed optimality conditions are further presented. Applications to nonlinear diffusion constrained problems as well as quasistatic elastoviscoplastic bilateral contact problems exemplify the theory.

HIV/AIDS-related social anxieties in adolescents in three African countries.

PubMed

Venier, J L; Ross, M W; Akande, A

1998-02-01

This study examines the social anxieties associated with HIV prevention in adolescents in three African countries (Nigeria, Kenya, and Zimbabwe). The subjects used in this study were black Africans in form 2 or grade 10 in public high schools (Nigeria, n = 387; Kenya, n = 274; Zimbabwe n = 313). Subjects responded to the 33 item AIDS Social Assertiveness Scale (ASAS). Data indicated similar factor structures for each of the three countries and included five factors. The combined sample factor intercorrelations were modestly but significantly correlated. The mean scores for each factor were compared, and ANOVA of the factors by country, by gender, and by interaction between country and gender were performed. The factor structures were very similar between countries, each including five factors that had similar themes: condom interactions, refusal of risk, confiding in significant others, contact with people with HIV/AIDS, and general assertiveness. These factor structures were also very similar to one found in previous studies of Australian adolescents on the ASAS. The Kenyan means for four of the five factors were significantly lower than those for Nigeria, and were also significantly lower than the Zimbabwean means for two of the five factors, suggesting that Kenyan students are less anxious about social situations related to HIV/AIDS than others. Significant variance was found for several factors due to gender, country, and the interaction between gender and country. These results have important implications for designing education programs. The similarities of anxieties regarding HIV/AIDS social situations suggest that these clusters of social barriers to reduction of HIV infection risk might form the basis of educational interventions, and that dimensions of HIV social anxieties are similar across countries.

A reaction-diffusion model for market fluctuations - A relation between price change and traded volumes

NASA Astrophysics Data System (ADS)

Yuvan, Steven; Bier, Martin

2018-02-01

Two decades ago Bak et al. (1997) [3] proposed a reaction-diffusion model to describe market fluctuations. In the model buyers and sellers diffuse from opposite ends of a 1D interval that represents a price range. Trades occur when buyers and sellers meet. We show analytically and numerically that the model well reproduces the square-root relation between traded volumes and price changes that is observed in real-life markets. The result is remarkable as this relation has commonly been explained in terms of more elaborate trader strategies. We furthermore explain why the square-root relation is robust under model modifications and we show how real-life bond market data exhibit the square-root relation.

The arbitrary order mimetic finite difference method for a diffusion equation with a non-symmetric diffusion tensor

NASA Astrophysics Data System (ADS)

Gyrya, V.; Lipnikov, K.

2017-11-01

We present the arbitrary order mimetic finite difference (MFD) discretization for the diffusion equation with non-symmetric tensorial diffusion coefficient in a mixed formulation on general polygonal meshes. The diffusion tensor is assumed to be positive definite. The asymmetry of the diffusion tensor requires changes to the standard MFD construction. We present new approach for the construction that guarantees positive definiteness of the non-symmetric mass matrix in the space of discrete velocities. The numerically observed convergence rate for the scalar quantity matches the predicted one in the case of the lowest order mimetic scheme. For higher orders schemes, we observed super-convergence by one order for the scalar variable which is consistent with the previously published result for a symmetric diffusion tensor. The new scheme was also tested on a time-dependent problem modeling the Hall effect in the resistive magnetohydrodynamics.

[Present situation of awareness of acquired immune deficiency syndrome (AIDS) knowledge and AIDS-related behaviors among youth students in gay dating sites].

PubMed

2017-06-18

To investigate the awareness of acquired immune deficiency syndrome (AIDS) knowledge and AIDS-related behaviors among youth students in gay dating sites, and to provide evidences for AIDS prevention education through the internet. The students in gay dating sites, selected by a snowball sampling, were interviewed by questionnaires. Chi-square tests were used to analyze the awareness of AIDS knowledge among the students of different characteristics. The Logistic regression was used to analyze the factors associated with ever testing for HIV. In the study, 469 youth students in gay dating sites filled in the questionnaires, and a total of 442 (94.2%) valid samples were collected. The awareness of HIV/AIDS knowledge for the public among the youth students in gay dating sites was 83.9% (371).The awareness of HIV/AIDS knowledge for the youth students was 77.1% (341), and the rate of ever testing for HIV was 52.0% (230). The awareness of HIV/AIDS knowledge for the public in the students were different in different age groups (P=0.001), different marital statuses (P<0.001), different sexual orientations (P<0.001), and different genders of the first sexual partner (P<0.001). The awareness of HIV/AIDS knowledge for the youth students were different in different age groups (P=0.010), different marital status (P=0.004), different sexual orientations (P<0.001), and different genders of the first sexual partner (P<0.001). The rate of ever having sexual intercourse among the youth students in gay dating sites was 75.1% (332), and the rate of multiple sexual partnerships among the youth students was 41.3% (137). Compared with homosexual orientation, sexual orientation as heterosexual (OR=0.282, 95%CI: 0.151 to 0.528) and not sure (OR=0.175, 95%CI: 0.035 to 0.885) were risk factors of ever testing for HIV. Multiple sexual partnerships (OR=2.103, 95%CI: 1.278 to 3.462) were promoting factors of ever testing for HIV. The rate of high-risk behaviors among the youth students in gay

Trend of HIV/AIDS Prevalence and Related Interventions Administered in Prisons of Iran -13 Years’ Experience

PubMed Central

SHAHBAZI, Mohammad; FARNIA, Marzieh; RAHMANI, Khaled; MORADI, Ghobad

2014-01-01

Abstract Background HIV/AIDS epidemic is concentrated among injecting drug users in Iran. Like many other countries with HIV/AIDS concentrated epidemic, prisons are high risk areas for spreading HIV/AIDS. The aim of this paper was to study the trend of HIV/AIDS prevalence and related interventions administered in prisons of Iran during a 13 years period Methods This cross sectional study was conducted using the data collected from the sentinel sites in all prisons in the country and it also used the data about Harm Reduction interventions which has been implemented by Iran Prisons Organization. To evaluate the correlation between the prevalence and each of administered interventions in prisons the Correlation Coefficient Test was used for the second half of the mentioned time period Results The prevalence of HIV/AIDS in prisons had increased rapidly in the early stages of epidemic, so that in 2002 the prevalence raised to 3.83%. Followed by the expansion of Methadone Maintenance Therapy and development of Triangular Clinics, HIV/AIDS prevalence in prisons declined. There was a relationship between interventions and the prevalence of HIV/AIDS. Conclusion In regions and countries where the epidemic is highly prevalent among injecting drug users and prisoners, Methadone Maintenance Therapy and development of Triangular Clinics can be utilized to control HIV/AIDS epidemic quickly. PMID:26005657

Unhealthy Substance Use Behaviors as Symptom-Related Self-Care in HIV/AIDS

PubMed Central

Brion, John M.; Rose, Carol Dawson; Nicholas, Patrice K.; Sloane, Rick; Voss, Joachim G.; Corless, Inge B.; Lindgren, Teri G.; Wantland, Dean J.; Kemppainen, Jeanne K.; Sefcik, Elizabeth F.; Nokes, Kathleen M.; Kirksey, Kenn M.; Eller, Lucille Sanzero; Hamilton, Mary Jane; Holzemer, William L.; Portillo, Carmen J.; Mendez, Marta Rivero; Robinson, Linda M.; Moezzi, Shanaz; Rosa, Maria; Human, Sarie; Maryland, Mary; Arudo, John; Ros, Ana Viamonte; Nicholas, Thomas P.; Cuca, Yvette; Huang, Emily; Bain, Catherine; Tyer-Viola, Lynda; Zang, Sheryl M.; Shannon, Maureen; Peters-Lewis, Angelleen

2014-01-01

The prevalence of symptoms in HIV disease can be associated with HIV disease itself, comorbid illness, and/or antiretroviral therapy. Unhealthy substance use behaviors, particularly substance-use behaviors including heavy alcohol intake, marijuana use, other illicit drug use, and cigarette smoking, are engaged in by many HIV-positive individuals, often as a way to manage disease-related symptoms. This study is a secondary data analysis of baseline data from a larger randomized-controlled trial of an HIV/AIDS Symptom Management Manual. In the present study, the prevalence and characteristics of unhealthy substance use behaviors in relation to HIV/AIDS symptoms are examined. Subjects were recruited from a variety of settings which provide HIV/AIDS care and treatment. The mean age of the sample (n=775) was 42.8 years (SD=9.6) and nearly thirty-nine percent (38.5%) of the sample was female. The racial demographics of the sample were: 28% African American, 28% Hispanic, 21% White/Caucasian, 16% African from Kenya or South Africa, 1% Asian, and 5% self-described as “Other.” The mean number of years living with HIV was reported to be 9.1 years (SD=6.6).Specific self-reported unhealthy substance-use behaviors were use of marijuana (n= 111; 14.3%), cigarette smoking (n=355; 45.8%), heavy alcohol use (n= 66; 8.5%), and illicit drugs (n= 98; 12.6%). A subset of individuals who identified high levels of specific symptoms also reported significantly higher substance use behaviors including amphetamine and injection drug use in addition to heavy alcohol use, cigarette smoking, and marijuana use. Implications for clinical practice include assessment of self-care behaviors, screening for substance abuse, and education of persons related to self-management across the trajectory of HIV disease. PMID:21352430

Computer-aided, multi-modal, and compression diffuse optical studies of breast tissue

NASA Astrophysics Data System (ADS)

Busch, David Richard, Jr.

Diffuse Optical Tomography and Spectroscopy permit measurement of important physiological parameters non-invasively through ˜10 cm of tissue. I have applied these techniques in measurements of human breast and breast cancer. My thesis integrates three loosely connected themes in this context: multi-modal breast cancer imaging, automated data analysis of breast cancer images, and microvascular hemodynamics of breast under compression. As per the first theme, I describe construction, testing, and the initial clinical usage of two generations of imaging systems for simultaneous diffuse optical and magnetic resonance imaging. The second project develops a statistical analysis of optical breast data from many spatial locations in a population of cancers to derive a novel optical signature of malignancy; I then apply this data-derived signature for localization of cancer in additional subjects. Finally, I construct and deploy diffuse optical instrumentation to measure blood content and blood flow during breast compression; besides optics, this research has implications for any method employing breast compression, e.g., mammography.

Combustion Diagnostics and Flow Visualization of Hypergolic Combustion and Gelled Mixing Behavior

DTIC Science & Technology

1997-12-19

difference. Also, Exciplex Flourescence imaging has been implented to visualize diffusion layers which form at the contact interface of mixing...have been implemented and developed as a result of this effort. Among these techniques the most noteworthy involves a unique application of Exciplex ...fluorescence for visualization of diffusion layers formed between mixing liquids. Time resolved images of Exciplex fluorescence have been obtained

Effects of g-Jitter on Diffusion in Binary Liquids

NASA Technical Reports Server (NTRS)

Duval, Walter M. B.

1999-01-01

The microgravity environment offers the potential to measure the binary diffusion coefficients in liquids without the masking effects introduced by buoyancy-induced flows due to Earth s gravity. However, the background g-jitter (vibrations from the shuttle, onboard machinery, and crew) normally encountered in many shuttle experiments may alter the benefits of the microgravity environment and introduce vibrations that could offset its intrinsic advantages. An experiment during STS-85 (August 1997) used the Microgravity Vibration Isolation Mount (MIM) to isolate and introduce controlled vibrations to two miscible liquids inside a cavity to study the effects of g-jitter on liquid diffusion. Diffusion in a nonhomogeneous liquid system is caused by a nonequilibrium condition that results in the transport of mass (dispersion of the different kinds of liquid molecules) to approach equilibrium. The dynamic state of the system tends toward equilibrium such that the system becomes homogeneous. An everyday example is the mixing of cream and coffee (a nonhomogeneous system) via stirring. The cream diffuses into the coffee, thus forming a homogeneous system. At equilibrium the system is said to be mixed. However, during stirring, simple observations show complex flow field dynamics-stretching and folding of material interfaces, thinning of striation thickness, self-similar patterns, and so on. This example illustrates that, even though mixing occurs via mass diffusion, stirring to enhance transport plays a major role. Stirring can be induced either by mechanical means (spoon or plastic stirrer) or via buoyancy-induced forces caused by Earth s gravity. Accurate measurements of binary diffusion coefficients are often inhibited by buoyancy-induced flows. The microgravity environment minimizes the effect of buoyancy-induced flows and allows the true diffusion limit to be achieved. One goal of this experiment was to show that the microgravity environment suppresses buoyancy

A numerical study of circulation driven by mixing over a submarine bank

NASA Astrophysics Data System (ADS)

Cummins, Patrick F.; Foreman, Michael G. G.

1998-04-01

A primitive equation model is applied to study the spin-up of a linearly stratified, rotating fluid over an isolated topographic bank. The model has vertical eddy mixing coefficients that decay away from the bottom over a specified e-folding scale. No external flows are imposed, and a circulation develops due solely to diffusion over the sea bed. Vertical mixing, coupled with the condition of zero diffusive flux of heat through the sea floor, leads to a distortion of isothermal surfaces near the bottom. The associated radial pressure gradients drive a radial-overturning circulation with upslope flow just above the bottom and downslope flows at greater height. Coriolis forces on the radial flows accelerate a verticallysheared azimuthal (alongslope) circulation. Near the bottom the azimuthal motion is cyclonic (upwelling favourable), while outside the boundary layer, the motion is anticyclonic. Sensitivity experiments show that this pattern is robust and maintained even with constant mixing coefficients. Attention is given to the driving mechanism for the depth-averaged azimuthal motion. An analysis of the relative angular momentum balance determines that the torque associated with bottom stresses drives the anticyclonic depth-averaged flow. In terms of vorticity, the anticyclonic vortex over the bank arises due to the curl of bottom stress divided by the depth. A parameter sensitivity study indicates that the depth-averaged flow is relatively insensitive to variations in the bottom drag coefficient.

Development of a multimedia educational programme for first-time hearing aid users: a participatory design.

PubMed

Ferguson, Melanie; Leighton, Paul; Brandreth, Marian; Wharrad, Heather

2018-05-02

To develop content for a series of interactive video tutorials (or reusable learning objects, RLOs) for first-time adult hearing aid users, to enhance knowledge of hearing aids and communication. RLO content was based on an electronically-delivered Delphi review, workshops, and iterative peer-review and feedback using a mixed-methods participatory approach. An expert panel of 33 hearing healthcare professionals, and workshops involving 32 hearing aid users and 11 audiologists. This ensured that social, emotional and practical experiences of the end-user alongside clinical validity were captured. Content for evidence-based, self-contained RLOs based on pedagogical principles was developed for delivery via DVD for television, PC or internet. Content was developed based on Delphi review statements about essential information that reached consensus (≥90%), visual representations of relevant concepts relating to hearing aids and communication, and iterative peer-review and feedback of content. This participatory approach recognises and involves key stakeholders in the design process to create content for a user-friendly multimedia educational intervention, to supplement the clinical management of first-time hearing aid users. We propose participatory methodologies are used in the development of content for e-learning interventions in hearing-related research and clinical practice.

Molecular simulations of diffusion in electrolytes

NASA Astrophysics Data System (ADS)

Wheeler, Dean Richard

This work demonstrates new methodologies for simulating multicomponent diffusion in concentrated solutions using molecular dynamics (MD). Experimental diffusion data for concentrated multicomponent solutions are often lacking, as are accurate methods of predicting diffusion for nonideal solutions. MD can be a viable means of understanding and predicting multicomponent diffusion. While there have been several prior reports of MD simulations of mutual diffusion, no satisfactory expressions for simulating Stefan-Maxwell diffusivities for an arbitrary number of species exist. The approaches developed here allow for the computation of a full diffusion matrix for any number of species in both nonequilibrium and equilibrium MD ensembles. Our nonequilibrium approach is based on the application of constant external fields to drive species diffusion. Our equilibrium approach uses a newly developed Green-Kubo formula for Stefan-Maxwell diffusivities. In addition, as part of this work, we demonstrate a widely applicable means of increasing the computational efficiency of the Ewald sum, a technique for handling long-range Coulombic interactions in simulations. The theoretical development is applicable to any solution which can be simulated using MD; nevertheless, our primary interest is in electrochemical applications. To this end, the methods are tested by simulations of aqueous salt solutions and lithium-battery electrolytes. KCl and NaCl aqueous solutions were simulated over the concentration range 1 to 4 molal. Intermolecular-potential models were parameterized for these transport-based simulations. This work is the first to simulate all three independent diffusion coefficients for aqueous NaCl and KCl solutions. The results show that the nonequilibrium and equilibrium methods are consistent with each other, and in moderate agreement with experiment. We simulate lithium-battery electrolytes containing LiPF6 in propylene carbonate and mixed ethylene carbonate

Molecular Profiling Reveals Biologically Discrete Subsets and Pathways of Progression in Diffuse Glioma.

PubMed

Ceccarelli, Michele; Barthel, Floris P; Malta, Tathiane M; Sabedot, Thais S; Salama, Sofie R; Murray, Bradley A; Morozova, Olena; Newton, Yulia; Radenbaugh, Amie; Pagnotta, Stefano M; Anjum, Samreen; Wang, Jiguang; Manyam, Ganiraju; Zoppoli, Pietro; Ling, Shiyun; Rao, Arjun A; Grifford, Mia; Cherniack, Andrew D; Zhang, Hailei; Poisson, Laila; Carlotti, Carlos Gilberto; Tirapelli, Daniela Pretti da Cunha; Rao, Arvind; Mikkelsen, Tom; Lau, Ching C; Yung, W K Alfred; Rabadan, Raul; Huse, Jason; Brat, Daniel J; Lehman, Norman L; Barnholtz-Sloan, Jill S; Zheng, Siyuan; Hess, Kenneth; Rao, Ganesh; Meyerson, Matthew; Beroukhim, Rameen; Cooper, Lee; Akbani, Rehan; Wrensch, Margaret; Haussler, David; Aldape, Kenneth D; Laird, Peter W; Gutmann, David H; Noushmehr, Houtan; Iavarone, Antonio; Verhaak, Roel G W

2016-01-28

Therapy development for adult diffuse glioma is hindered by incomplete knowledge of somatic glioma driving alterations and suboptimal disease classification. We defined the complete set of genes associated with 1,122 diffuse grade II-III-IV gliomas from The Cancer Genome Atlas and used molecular profiles to improve disease classification, identify molecular correlations, and provide insights into the progression from low- to high-grade disease. Whole-genome sequencing data analysis determined that ATRX but not TERT promoter mutations are associated with increased telomere length. Recent advances in glioma classification based on IDH mutation and 1p/19q co-deletion status were recapitulated through analysis of DNA methylation profiles, which identified clinically relevant molecular subsets. A subtype of IDH mutant glioma was associated with DNA demethylation and poor outcome; a group of IDH-wild-type diffuse glioma showed molecular similarity to pilocytic astrocytoma and relatively favorable survival. Understanding of cohesive disease groups may aid improved clinical outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Breakdown of the Stokes-Einstein Relation for the Rotational Diffusivity of Polymer Grafted Nanoparticles in Polymer Melts.

PubMed

Maldonado-Camargo, Lorena; Rinaldi, Carlos

2016-11-09

We report observations of breakdown of the Stokes-Einstein relation for the rotational diffusivity of polymer-grafted spherical nanoparticles in polymer melts. The rotational diffusivity of magnetic nanoparticles coated with poly(ethylene glycol) dispersed in poly(ethylene glycol) melts was determined through dynamic magnetic susceptibility measurements of the collective rotation of the magnetic nanoparticles due to imposed time-varying magnetic torques. These measurements clearly demonstrate the existence of a critical molecular weight for the melt polymer, below which the Stokes-Einstein relation accurately describes the rotational diffusivity of the polymer-grafted nanoparticles and above which the Stokes-Einstein relation ceases to apply. This critical molecular weight was found to correspond to a chain contour length that approximates the hydrodynamic diameter of the nanoparticles.

Validating survey measurement scales for AIDS-related knowledge and stigma among construction workers in South Africa.

PubMed

Bowen, Paul; Govender, Rajen; Edwards, Peter

2016-01-23

Construction workers in South Africa are regarded as a high-risk group in the context of HIV/AIDS. HIV testing is pivotal to controlling HIV transmission and providing palliative care and AIDS-related knowledge and stigma are key issues in addressing the likelihood of testing behaviour. In exploring these issues, various studies have employed an 11-item AIDS-related knowledge scale (Kalichman and Simbayi, AIDS Care 16:572-580, 2004) and a 9-item stigma scale (Kalichman et al., AIDS Behav 9:135-143, 2005), but little evidence exists confirming the psychometric properties of these scales. Using survey data from 512 construction workers in the Western Cape, South Africa, this research examines the validity and reliability of the two scales through exploratory and confirmatory factor analysis and internal consistency tests. From confirmatory factor analysis, a revised 10-item knowledge scale was developed (χ2 /df ratio = 1.675, CFI = 0.982, RMSEA = 0.038, and Hoelter (95 %) = 393). A revised 8-item stigma scale was also developed (χ2 /df ratio = 1.929, CFI = 0.974, RMSEA = 0.045, and Hoelter (95 %) = 380). Both revised scales demonstrated good model fit and all factor loadings were significant (p < 0.01). Reliability analysis demonstrated excellent to good internal consistency, with alpha values of 0.80 and 0.74, respectively. Both revised scales also demonstrated satisfactory convergent and divergent validity. Limitations of the original survey from which the data was obtained include the failure to properly account for respondent selection of language for completion of the survey, use of ethnicity as a proxy for identifying the native language of participants, the limited geographical area from which the survey data was collected, and the limitations associated with the convenience sample. A limitation of the validation study was the lack of available data for a more robust examination of reliability beyond internal consistency, such as test-retest reliability. The

Diffuse pulmonary gallium accumulation with a normal chest radiogram in a homosexual man with pneumocystis carinii pneumonia. A case report

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

Moses, S.C.; Baker, S.R.; Seldin, M.F.

1983-12-01

A homosexual man with A.I.D.S. (acquired immunologic deficiency syndrome) and pneumocystis infestation was found to have diffuse Ga-67 uptake in the lungs with a coincident negative chest x-ray. While Ga-67 accumulates diffusely in the lungs in a variety of conditions, the present case is the first described in a patient with A.I.D.S. in which Ga-67 was positive before roentgenographic abnormalities were demonstrated. Thus, the use of Ga-67 scan, when A.I.D.S. is suspected, could help establish a diagnosis more promptly.

Ocean Turbulence, III: New GISS Vertical Mixing Scheme

NASA Technical Reports Server (NTRS)

Canuto, V. M.; Howard, A. M.; Cheng, Y.; Muller, C. J.; Leboissetier, A.; Jayne, S. R.

2010-01-01

ocean bottom, we adopt the enhanced bottom diffusivity expression used by previous authors but with a state of the art internal tidal energy formulation and replace the fixed Gamma-alpha = 0.2 with the RSM result that brings into the problem the Ri, R-rho dependence of the Gamma-alpha; the unresolved bottom drag, which has thus far been either ignored or modeled with heuristic relations, is modeled using a formalism we previously developed and tested in PBL studies. We carried out several tests without an OGCM. Prandtl and flux Richardson numbers vs. Ri. The RSM model reproduces both types of data satisfactorily. DD and Mixing efficiency Gamma-h(Ri,Rq). The RSM model reproduces well the NATRE data. Bimodal epsilon-distribution. NATRE data show that epsilon (Ri < 1) approximately equals 10epsilon(Ri > 1), which our model reproduces. Heat to salt flux ratio. In the Ri much greater than 1 regime, the RSM predictions reproduce the data satisfactorily. NATRE mass diffusivity. The z-profile of the mass diffusivity reproduces well the measurements at NATRE. The local form of the mixing scheme is algebraic with one cubic equation to solve.

Material transport in a wind and buoyancy forced mixed layer

NASA Astrophysics Data System (ADS)

Mensa, J. A.; Özgökmen, T.; Poje, A. C.; Imberger, J.

2016-02-01

Flows in the upper ocean mixed layer are responsible for the transport and dispersion of biogeochemical tracers, phytoplankton and buoyant pollutants, such as hydrocarbons from an oil spill. Material dispersion in mixed layer flows subject to diurnal buoyancy forcing and weak winds (|u10|=5ms-1) are investigated using a non-hydrostatic model. Both purely buoyancy-forced and combined wind- and buoyancy-forced flows are sampled using passive tracers, as well as 2D and 3D particles to explore characteristics of horizontal and vertical dispersion. It is found that the surface tracer patterns are determined by the convergence zones created by convection cells within a time scale of just a few hours. For pure convection, the results displayed the classic signature of Rayleigh-Benard cells. When combined with a wind stress, the convective cells become anisotropic in that the along-wind length scale gets much larger than the cross-wind scale. Horizontal relative dispersion computed by sampling the flow fields using both 2D and 3D passive particles is found to be consistent with the Richardson regime. Relative dispersion is an order of magnitude higher and 2D surface releases transition to Richardson regime faster in the wind-forced case. We also show that the buoyancy-forced case results in significantly lower amplitudes of scale-dependent horizontal relative diffusivity, kD(l), than those reported by Okubo (1970), while the wind- and buoyancy forced case shows a good agreement with Okubo's diffusivity amplitude, and scaling consistent with Richardson's 4/3rd law, kD(l) l4/3. The modelling results provide a framework for measuring material dispersion by mixed layer flow in future observational programs.

Efficient Computational Prototyping of Mixed Technology Microfluidic Components and Systems

DTIC Science & Technology

2002-08-01

AFRL-IF-RS-TR-2002-190 Final Technical Report August 2002 EFFICIENT COMPUTATIONAL PROTOTYPING OF MIXED TECHNOLOGY MICROFLUIDIC...SUBTITLE EFFICIENT COMPUTATIONAL PROTOTYPING OF MIXED TECHNOLOGY MICROFLUIDIC COMPONENTS AND SYSTEMS 6. AUTHOR(S) Narayan R. Aluru, Jacob White...Aided Design (CAD) tools for microfluidic components and systems were developed in this effort. Innovative numerical methods and algorithms for mixed

The hearing aid effect in 2013.

PubMed

Rauterkus, Erik P; Palmer, Catherine V

2014-10-01

The hearing aid effect is the term used to describe the assignment of negative attributes to individuals using hearing aids. The effect was first empirically identified in 1977 when it was reported that adults rating young children with and without hearing aids assigned negative attributes to the children depicted with hearing aids. Investigations in the 1980s and 1990s reported mixed results related to the extent of the hearing aid effect but continued to identify, on average, some negative attributes assigned to individuals wearing hearing aids. The specific aim of this research was to investigate whether the hearing aid effect has diminished in the past several decades by replicating the methods of previous studies for testing the hearing aid effect while using updated devices. Five device configurations were rated across eight attributes. RESULTS for each attribute were considered separately. A total of 24 adults judged pictures of young men wearing various ear level technologies across 8 attributes on a 7-point Likert scale. Five young men between ages 15 and 17 yr were photographed wearing each of five device configurations including (1) a standard-sized behind-the-ear (BTE) hearing aid coupled to an earmold with #13 tubing, (2) a mini-BTE hearing aid with a slim tube open-fit configuration, (3) a completely-in-the-canal hearing aid that could not be seen because of its location in the ear canal, (4) an earbud, and (5) a Bluetooth receiver. The 24 raters saw pictures of each of the 5 young men with each wearing one of the 5 devices so that devices and young men were never judged twice by the same observer. All judgments of each device, regardless of the young man modeling the device, were combined in the data analysis. The effect of device types on judgments was tested using a one-way between-participant analysis of variance. There was a significant difference on the judgment of age and trustworthiness level among the five devices. However, our post hoc

Raman Spectroscopy of Isotopic Water Diffusion in Ultraviscous, Glassy, and Gel States in Aerosol by Use of Optical Tweezers.

PubMed

Davies, James F; Wilson, Kevin R

2016-02-16

The formation of ultraviscous, glassy, and amorphous gel states in aqueous aerosol following the loss of water results in nonequilibrium dynamics due to the extended time scales for diffusive mixing. Existing techniques for measuring water diffusion by isotopic exchange are limited by contact of samples with the substrate, and methods applied to infer diffusion coefficients from mass transport in levitated droplets requires analysis by complex coupled differential equations to derive diffusion coefficients. We present a new technique that combines contactless levitation with aerosol optical tweezers with isotopic exchange (D2O/H2O) to measure the water diffusion coefficient over a broad range (Dw ≈ 10(-12)-10(-17) m(2)·s(-1)) in viscous organic liquids (citric acid, sucrose, and shikimic acid) and inorganic gels (magnesium sulfate, MgSO4). For the organic liquids in binary and ternary mixtures, Dw depends on relative humidity and follows a simple compositional Vignes relationship. In MgSO4 droplets, water diffusivity decreases sharply with water activity and is consistent with predictions from percolation theory. These measurements show that, by combining micrometer-sized particle levitation (a contactless measurement with rapid mixing times) with an established probe of water diffusion, Dw can be simply and directly quantified for amorphous and glassy states that are inaccessible to existing methods.

Raman Spectroscopy of Isotopic Water Diffusion in Ultraviscous, Glassy, and Gel States in Aerosol by Use of Optical Tweezers

DOE PAGES

Davies, James F.; Wilson, Kevin R.

2016-01-11

The formation of ultraviscous, glassy, and amorphous gel states in aqueous aerosol following the loss of water results in nonequilibrium dynamics due to the extended time scales for diffusive mixing. Existing techniques for measuring water diffusion by isotopic exchange are limited by contact of samples with the substrate, and methods applied to infer diffusion coefficients from mass transport in levitated droplets requires analysis by complex coupled differential equations to derive diffusion coefficients. Here, we present a new technique that combines contactless levitation with aerosol optical tweezers with isotopic exchange (D 2O/H 2O) to measure the water diffusion coefficient over amore » broad range (D w ≈ 10 -12-10 -17 m 2s -1) in viscous organic liquids (citric acid, sucrose, and shikimic acid) and inorganic gels (magnesium sulfate, MgSO 4). For the organic liquids in binary and ternary mixtures, D w depends on relative humidity and follows a simple compositional Vignes relationship. In MgSO 4 droplets, water diffusivity decreases sharply with water activity and is consistent with predictions from percolation theory. These measurements show that, by combining micrometer-sized particle levitation (a contactless measurement with rapid mixing times) with an established probe of water diffusion, D w can be simply and directly quantified for amorphous and glassy states that are inaccessible to existing methods.« less

Knowledge, attitudes and sexual practices of adolescents with mild retardation, in relation HIV/AIDS.

PubMed

Dawood, Naseema; Bhagwanjee, Anil; Govender, Kay; Chohan, Ebrahim

2006-05-01

This study investigates the knowledge, attitudes and sexual practices of adolescents with mild mental retardation (MMR) in relation to HIV/AIDS. Questionnaires were personally administered to a saturation sample of 90 adolescents with MMR drawn from one specialised educational institution in Durban, South Africa. The study revealed critical gaps and erroneous beliefs regarding knowledge of HIV/AIDS, especially with regard to its existence, transmission and cure. Participants indicated a high degree of exposure to various sources of information, particularly media messages. The results indicate that gender-role prescriptions and prevailing social constructions of immorality have had a negative influence on the attitudes and behaviour of participants, particularly with regard to sexual practices and preventative risk behaviours. Furthermore, the sample was found to have low levels of self-efficacy in relation to sexual negotiation and decision-making, more specifically with regard to condom use. It should be noted, however, that only a small proportion of the sample was sexually active and the use of contraceptives was accordingly found to be extremely low. The findings are discussed against the backdrop of the empirical literature on HIV/AIDS, developmental theory, and pertinent theories and models of health behaviour. This study may help to promote a better understanding of the psycho-educational dynamics of HIV infection in this special group of adolescents, and also help to inform attempts to tailor suitable educational programmes, as well as promote further research to add to our knowledge as we address the problems of HIV/AIDS among this group.

The arbitrary order mimetic finite difference method for a diffusion equation with a non-symmetric diffusion tensor

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

Gyrya, V.; Lipnikov, K.

Here, we present the arbitrary order mimetic finite difference (MFD) discretization for the diffusion equation with non-symmetric tensorial diffusion coefficient in a mixed formulation on general polygonal meshes. The diffusion tensor is assumed to be positive definite. The asymmetry of the diffusion tensor requires changes to the standard MFD construction. We also present new approach for the construction that guarantees positive definiteness of the non-symmetric mass matrix in the space of discrete velocities. The numerically observed convergence rate for the scalar quantity matches the predicted one in the case of the lowest order mimetic scheme. For higher orders schemes, wemore » observed super-convergence by one order for the scalar variable which is consistent with the previously published result for a symmetric diffusion tensor. The new scheme was also tested on a time-dependent problem modeling the Hall effect in the resistive magnetohydrodynamics.« less

The arbitrary order mimetic finite difference method for a diffusion equation with a non-symmetric diffusion tensor

DOE PAGES

Gyrya, V.; Lipnikov, K.

2017-07-18

Here, we present the arbitrary order mimetic finite difference (MFD) discretization for the diffusion equation with non-symmetric tensorial diffusion coefficient in a mixed formulation on general polygonal meshes. The diffusion tensor is assumed to be positive definite. The asymmetry of the diffusion tensor requires changes to the standard MFD construction. We also present new approach for the construction that guarantees positive definiteness of the non-symmetric mass matrix in the space of discrete velocities. The numerically observed convergence rate for the scalar quantity matches the predicted one in the case of the lowest order mimetic scheme. For higher orders schemes, wemore » observed super-convergence by one order for the scalar variable which is consistent with the previously published result for a symmetric diffusion tensor. The new scheme was also tested on a time-dependent problem modeling the Hall effect in the resistive magnetohydrodynamics.« less

Trends in AIDS-related mortality among people aged 60 years and older in Brazil: a nationwide population-based study.

PubMed

Lima, Mauricélia da Silveira; Firmo, Andréa Acioly Maia; Martins-Melo, Francisco Rogerlândio

2016-12-01

The success of antiretroviral therapy has led to an increase in the number of older people living with human immunodeficiency virus worldwide. This study analyzed the epidemiological patterns and time trends of acquired immunodeficiency syndrome (AIDS) related mortality in people aged 60 and older in Brazil from 2000 to 2011. Secondary mortality data from the Brazilian Mortality Information System was used to perform a nationwide population-based study, which included all AIDS-related deaths among people aged 60 years and older in Brazil from 2000 to 2011. Crude and age-adjusted mortality rates (per 100,000 inhabitants) were calculated by sex, age group and place of residence. Trends over time were assessed using joinpoint regression analysis. In the 12-year study period, 12,491,280 deaths were recorded in Brazil, of which 144,175 were AIDS-related deaths. A total of 8194 AIDS-related deaths was identified in people aged 60 years and older (0.12% of all deaths and 5.7% of AIDS-related deaths). The overall age-adjusted mortality rate for the period was 4.30 deaths/100,000 inhabitants (95% confidence interval: 3.99-4.64). Males (6.45 deaths/100,000 inhabitants), aged 60-64 years (6.63 deaths/100,000 inhabitants) and residing in the South region (5.94 deaths/100,000 inhabitants) had the highest mortality rates. We observed a significant increase in mortality at the national level and in all the Brazilian regions, with a sharper increase in the most socioeconomically disadvantaged regions of the country, such as the North and Northeast. The findings show that AIDS in older people is an increasing public health problem in Brazil, and reinforce the need to establish public policies for the prevention, early diagnosis and appropriate clinical treatment of this age group.

Some analyses of the chemistry and diffusion of SST exhaust materials during phase 3 of the wake period. [in lower stratosphere

NASA Technical Reports Server (NTRS)

Hilst, G. R.; Donaldson, C. D.; Contiliano, R. M.

1973-01-01

In the generally stably stratified lower stratosphere, SST exhaust plumes could spend a significant length of time in a relatively undispersed state. This effort has utilized invariant modeling techniques to simulate the separate and combined effects of atmospheric turbulence, turbulent diffusion, and chemical reactions of SST exhaust materials in the lower stratosphere. The primary results to date are: (1) The combination of relatively slow diffusive mixing and rapid chemical reactions during the Phase III wake period minimizes the effect of SST exhausts on O3 depletion by the so-called NOx catalytic cycle. While the SST-produced NO is substantially above background concentrations, it appears diffusive mixing of NO and O3 is simply too slow to produce the O3 depletions originally proposed. (2) The time required to dilute the SST exhaust plume may be a significant fraction of the total time these materials are resident in the lower stratosphere. If this is the case, then prior estimates of the environmental impact of these materials must be revised significantly downward.

Effects of mixing on resolved and unresolved scales on stratospheric age of air

NASA Astrophysics Data System (ADS)

Dietmüller, Simone; Garny, Hella; Plöger, Felix; Jöckel, Patrick; Cai, Duy

2017-06-01

Mean age of air (AoA) is a widely used metric to describe the transport along the Brewer-Dobson circulation. We seek to untangle the effects of different processes on the simulation of AoA, using the chemistry-climate model EMAC (ECHAM/MESSy Atmospheric Chemistry) and the Chemical Lagrangian Model of the Stratosphere (CLaMS). Here, the effects of residual transport and two-way mixing on AoA are calculated. To do so, we calculate the residual circulation transit time (RCTT). The difference of AoA and RCTT is defined as aging by mixing. However, as diffusion is also included in this difference, we further use a method to directly calculate aging by mixing on resolved scales. Comparing these two methods of calculating aging by mixing allows for separating the effect of unresolved aging by mixing (which we term aging by diffusion in the following) in EMAC and CLaMS. We find that diffusion impacts AoA by making air older, but its contribution plays a minor role (order of 10 %) in all simulations. However, due to the different advection schemes of the two models, aging by diffusion has a larger effect on AoA and mixing efficiency in EMAC, compared to CLaMS. Regarding the trends in AoA, in CLaMS the AoA trend is negative throughout the stratosphere except in the Northern Hemisphere middle stratosphere, consistent with observations. This slight positive trend is neither reproduced in a free-running nor in a nudged simulation with EMAC - in both simulations the AoA trend is negative throughout the stratosphere. Trends in AoA are mainly driven by the contributions of RCTT and aging by mixing, whereas the contribution of aging by diffusion plays a minor role.

Dynamical modes of two almost identical chemical oscillators connected via both pulsatile and diffusive coupling.

PubMed

Safonov, Dmitry A; Vanag, Vladimir K

2018-05-03

The dynamical regimes of two almost identical Belousov-Zhabotinsky oscillators with both pulsatile (with time delay) and diffusive coupling have been studied theoretically with the aid of ordinary differential equations for four combinations of these types of coupling: inhibitory diffusive and inhibitory pulsatile (IDIP); excitatory diffusive and inhibitory pulsatile; inhibitory diffusive and excitatory pulsatile; and finally, excitatory diffusive and excitatory pulsatile (EDEP). The combination of two types of coupling creates a condition for new feedback, which promotes new dynamical modes for the IDIP and EDEP coupling.

Surface wind mixing in the Regional Ocean Modeling System (ROMS)

NASA Astrophysics Data System (ADS)

Robertson, Robin; Hartlipp, Paul

2017-12-01

Mixing at the ocean surface is key for atmosphere-ocean interactions and the distribution of heat, energy, and gases in the upper ocean. Winds are the primary force for surface mixing. To properly simulate upper ocean dynamics and the flux of these quantities within the upper ocean, models must reproduce mixing in the upper ocean. To evaluate the performance of the Regional Ocean Modeling System (ROMS) in replicating the surface mixing, the results of four different vertical mixing parameterizations were compared against observations, using the surface mixed layer depth, the temperature fields, and observed diffusivities for comparisons. The vertical mixing parameterizations investigated were Mellor- Yamada 2.5 level turbulent closure (MY), Large- McWilliams- Doney Kpp (LMD), Nakanishi- Niino (NN), and the generic length scale (GLS) schemes. This was done for one temperate site in deep water in the Eastern Pacific and three shallow water sites in the Baltic Sea. The model reproduced the surface mixed layer depth reasonably well for all sites; however, the temperature fields were reproduced well for the deep site, but not for the shallow Baltic Sea sites. In the Baltic Sea, the models overmixed the water column after a few days. Vertical temperature diffusivities were higher than those observed and did not show the temporal fluctuations present in the observations. The best performance was by NN and MY; however, MY became unstable in two of the shallow simulations with high winds. The performance of GLS nearly as good as NN and MY. LMD had the poorest performance as it generated temperature diffusivities that were too high and induced too much mixing. Further observational comparisons are needed to evaluate the effects of different stratification and wind conditions and the limitations on the vertical mixing parameterizations.

Health Emergency 2003: The Spread of Drug-Related AIDS and Hepatitis C among African American and Latinos. Health Emergency Series.

ERIC Educational Resources Information Center

Day, Dawn

This report is the fifth in a series detailing the impact of the injection-related AIDS epidemic on African Americans and Latinos. Ten chapters include: (1) "Health Emergency: The Spread of AIDS among African Americans Who Inject Drugs"; (2) "Health Emergency: The Spread of AIDS Among Latinos Who Inject Drugs"; (3) "A…

Joining of Silicon Carbide: Diffusion Bond Optimization and Characterization

NASA Technical Reports Server (NTRS)

Halbig, Michael C.; Singh, Mrityunjay

2008-01-01

Joining and integration methods are critically needed as enabling technologies for the full utilization of advanced ceramic components in aerospace and aeronautics applications. One such application is a lean direct injector for a turbine engine to achieve low NOx emissions. In the application, several SiC substrates with different hole patterns to form fuel and combustion air channels are bonded to form the injector. Diffusion bonding is a joining approach that offers uniform bonds with high temperature capability, chemical stability, and high strength. Diffusion bonding was investigated with the aid of titanium foils and coatings as the interlayer between SiC substrates to aid bonding. The influence of such variables as interlayer type, interlayer thickness, substrate finish, and processing time were investigated. Optical microscopy, scanning electron microscopy, and electron microprobe analysis were used to characterize the bonds and to identify the reaction formed phases.

Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity.

PubMed

Xu, Jing; Zhang, Jianshun S; Liu, Xiaoyu; Gao, Zhi

2012-06-01

The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50%, and 70% RH). The "green" materials contained recycled materials and were friendly to environment. A dynamic dual-chamber test method was used. Results showed that a higher relative humidity led to a larger effective diffusion coefficient for two kinds of wallboards and carpet. The carpet was also found to be very permeable resulting in an effective diffusion coefficient at the same order of magnitude with the formaldehyde diffusion coefficient in air. The partition coefficient (K(ma)) of formaldehyde in conventional wallboard was 1.52 times larger at 50% RH than at 20% RH, whereas it decreased slightly from 50% to 70% RH, presumably due to the combined effects of water solubility of formaldehyde and micro-pore blocking by condensed moisture at the high RH level. The partition coefficient of formaldehyde increased slightly with the increase of relative humidity in "green" wallboard and "green" carpet. At the same relative humidity level, the "green" wallboard had larger partition coefficient and effective diffusion coefficient than the conventional wallboard, presumably due to the micro-pore structure differences between the two materials. The data generated could be used to assess the sorption effects of formaldehyde on building materials and to evaluate its impact on the formaldehyde concentration in buildings.

The diffusion of a community-level HIV intervention for women: lessons learned and best practices.

PubMed

King, Winifred; Nu'Man, Jeanette; Fuller, Talleria R; Brown, Mari; Smith, Shuenae; Howell, A Vyann; Little, Stacey; Patrick, Patricia; Glover, LaShon

2008-09-01

Abstract Early in the HIV/AIDS epidemic in the United States, relatively few women were diagnosed with HIV infection and AIDS. Today, the epidemic represents a growing and persistent health threat to women in the United States, especially young women and women of color. In 2005, the leading cause of HIV infection among African American women and Latinas was heterosexual contact. In addressing HIV prevention needs among women, community-level strategies are needed to increase consistent condom use by women and their partners and to change community norms to support safer sex behaviors. The Real AIDS Prevention Project (RAPP) is a community-based HIV prevention intervention for women and their partners. RAPP is based on a community mobilization model that involves a combination of activities, including street outreach, one-on-one discussions called stage-based encounters, role model stories, community networks, and small group activities. The objectives of RAPP are to increase consistent condom use by women and their partners and change community norms associated with perceptions of condom use and high-risk behaviors in an effort to make safer sex practice more acceptable. This paper describes the Centers for Disease Control and Prevention (CDC) Division of HIV/AIDS Prevention (DHAP) effort to nationally diffuse RAPP from March 2003 through May 2007 and lessons learned from that diffusion experience. The paper specifically discusses (1) collaborating and planning with researchers, (2) a diffusion needs assessment that was designed to assess prior implementation experiences among select agencies, (3) developing the intervention package, (4) developing and piloting training for community-based organizations (CBOs), (5) a rollout of national trainings for health departments and community-based organizations interested in implementing RAPP, and (6) ongoing quality assurance activities and the provision of technical assistance and support. RAPP has been proven effective

An ideal-typical model for comparing interprofessional relations and skill mix in health care.

PubMed

Schönfelder, Walter; Nilsen, Elin Anita

2016-11-08

Comparisons of health system performance, including the regulations of interprofessional relations and the skill mix between health professions are challenging. National strategies for regulating interprofessional relations vary widely across European health care systems. Unambiguously defined and generally accepted performance indicators have to remain generic, with limited power for recognizing the organizational structures regulating interprofessional relations in different health systems. A coherent framework for in-depth comparisons of different models for organizing interprofessional relations and the skill mix between professional groups is currently not available. This study aims to develop an ideal-typical framework for categorizing skill mix and interprofessional relations in health care, and to assess the potential impact for different ideal types on care coordination and integrated service delivery. A document analysis of the Health Systems in Transition (HiT) reports published by the European Observatory on Health Systems and Policies was conducted. The HiT reports to 31 European health systems were analyzed using a qualitative content analysis and a process of meaning condensation. The educational tracks available to nurses have an impact on the professional autonomy for nurses, the hierarchy between professional groups, the emphasis given to negotiating skill mix, interdisciplinary teamwork and the extent of cooperation across the health and social service interface. Based on the results of the document analysis, three ideal types for regulating interprofessional relations and skill mix in health care are delimited. For each ideal type, outcomes on service coordination and holistic service delivery are described. Comparisons of interprofessional relations are necessary for proactive health human resource policies. The proposed ideal-typical framework provides the means for in-depth comparisons of interprofessional relations in the health care

Using HIV&AIDS statistics in pre-service Mathematics Education to integrate HIV&AIDS education.

PubMed

van Laren, Linda

2012-12-01

In South Africa, the HIV&AIDS education policy documents indicate opportunities for integration across disciplines/subjects. There are different interpretations of integration/inclusion and mainstreaming HIV&AIDS education, and numerous levels of integration. Integration ensures that learners experience the disciplines/subjects as being linked and related, and integration is required to support and expand the learners' opportunities to attain skills, acquire knowledge and develop attitudes and values across the curriculum. This study makes use of self-study methodology where I, a teacher educator, aim to improve my practice through including HIV&AIDS statistics in Mathematics Education. This article focuses on how I used HIV&AIDS statistics to facilitate pre-service teacher reflection and introduce them to integration of HIV&AIDS education across the curriculum. After pre-service teachers were provided with HIV statistics, they drew a pie chart which graphically illustrated the situation and reflected on issues relating to HIV&AIDS. Three themes emerged from the analysis of their reflections. The themes relate to the need for further HIV&AIDS education, the changing pastoral role of teachers and the changing context of teaching. This information indicates that the use of statistics is an appropriate means of initiating the integration of HIV&AIDS education into the academic curriculum.

Detailed stress tensor measurements in a centrifugal compressor vaneless diffuser

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

Pinarbasi, A.; Johnson, M.W.

1996-04-01

Detailed flow measurements have been made in the vaneless diffuser of a large low-speed centrifugal compressor using hot-wire anemometry. The three time mean velocity components and full stress tensor distributions have been determined on eight measurement plans within the diffuser. High levels of Reynolds stress result in the rapid mixing out of the blade wake. Although high levels of turbulent kinetic energy are found in the passage wake, they are not associated with strong Reynolds stresses and hence the passage wake mixes out only slowly. Low-frequency meandering of the wake position is therefore likely to be responsible for the highmore » kinetic energy levels. The anisotropic nature of the turbulence suggests that Reynolds stress turbulence models are required for CFD modeling of diffuser flows.« less

Plasma kinetic effects on atomistic mix in one dimension and at structured interfaces (I)

NASA Astrophysics Data System (ADS)

Yin, L.; Albright, B. J.; Vold, E. L.; Taitano, W.; Chacon, L.; Simakov, A.

2017-10-01

Kinetic effects on interfacial mix are examined using VPIC simulations. In 1D, comparisons are made to the results of analytic theory in the small Knudsen number limit. While the bulk mixing properties of interfaces are in general agreement, differences arise near the low-concentration fronts during the early evolution of a sharp interface when the species' perpendicular scattering rate dominates over the slowing down rate. In kinetic simulations, the diffusion velocities can be larger or comparable to the ion thermal speeds, and the Knudsen number can be large. Super-diffusive growth in mix widths (Δx ta where a >=1/2) is seen before transition to the slow diffusive process predicted from theory (a =1/2). Mixing at interfaces leads to persistent, bulk, hydrodynamic features in the center of mass flow profiles as a result of diffusion and momentum conservation. These conclusions are drawn from VPIC results together with simulations from the RAGE hydrodynamics code with an implementation of diffusion and viscosity from theory and an implicit Vlasov-Fokker-Planck code iFP. In perturbed 2D and 3D interfaces, it is found that 1D ambipolarity is still valid and that initial perturbations flatten out on a-few-ps time scale, implying that finite diffusivity and viscosity can slow instability growth in ICF and HED settings. Work supported by the LANL ASC and Science programs.

Hydrodynamically induced fluid transfer and non-convective double-diffusion in microgravity sliding solvent diffusion cells

NASA Technical Reports Server (NTRS)

Pollmann, Konrad W.; Stodieck, Louis S.; Luttges, Marvin W.

1994-01-01

Microgravity can provide a diffusion-dominated environment for double-diffusion and diffusion-reaction experiments otherwise disrupted by buoyant convection or sedimentation. In sliding solvent diffusion cells, a diffusion interface between two liquid columns is achieved by aligning two offset sliding wells. Fluid in contact with the sliding lid of the cavities is subjected to an applied shear stress. The momentum change by the start/stop action of the well creates an additional hydrodynamical force. In microgravity, these viscous and inertial forces are sufficiently large to deform the diffusion interface and induce hydrodynamic transfer between the wells. A series of KC-135 parabolic flight experiments were conducted to characterize these effects and establish baseline data for microgravity diffusion experiments. Flow visualizations show the diffusion interface to be deformed in a sinusoidal fashion following well alignment. After the wells were separated again in a second sliding movement, the total induced liquid transfer was determined and normalized by the well aspect ratio. The normalized transfer decreased linearly with Reynolds number from 3.3 to 4.0% (w/v) for Re = 0.4 (Stokes flow) to a minimum of 1.0% for Re = 23 to 30. Reynolds numbers that provide minimum induced transfers are characterized by an interface that is highly deformed and unsuitable for diffusion measurements. Flat diffusion interfaces acceptable for diffusion measurements are obtained with Reynolds numbers on the order of 7 to 10. Microgravity experiments aboard a sounding rocket flight verified counterdiffusion of different solutes to be diffusion dominated. Ground control experiments showed enhanced mixing by double-diffusive convection. Careful selection of experimental parameters improves initial conditions and minimizes induced transfer rates.

Influences of external vs. core-shell mixing on aerosol optical properties at various relative humidities.

PubMed

Ramachandran, S; Srivastava, Rohit

2013-05-01

Aerosol optical properties of external and core-shell mixtures of aerosol species present in the atmosphere are calculated in this study for different relative humidities. Core-shell Mie calculations are performed using the values of radii, refractive indices and densities of aerosol species that act as core and shell, and the core-shell radius ratio. The single scattering albedo (SSA) is higher when the absorbing species (black carbon, BC) is the core, while for a sulfate core SSA does not vary significantly as the BC in the shell dominates the absorption. Absorption gets enhanced in core-shell mixing of absorbing and scattering aerosols when compared to their external mixture. Thus, SSA is significantly lower for a core-shell mixture than their external mixture. SSA is more sensitive to core-shell ratio than mode radius when BC is the core. The extinction coefficient, SSA and asymmetry parameter are higher for external mixing when compared to BC (core)-water soluble aerosol (shell), and water soluble aerosol (core)-BC (shell) mixtures in the relative humidity range of 0 to 90%. Spectral SSA exhibits the behaviour of the species which acts as a shell in core-shell mixing. The asymmetry parameter for an external mixture of water soluble aerosol and BC is higher than BC (core)-water soluble aerosol (shell) mixing and increases as function of relative humidity. The asymmetry parameter for the water soluble aerosol (core)-BC (shell) is independent of relative humidity as BC is hydrophobic. The asymmetry parameter of the core-shell mixture decreases when BC aerosols are involved in mixing, as the asymmetry parameter of BC is lower. Aerosol optical depth (AOD) of core-shell mixtures increases at a higher rate when the relative humidity exceeds 70% in continental clean and urban aerosol models, whereas AOD remains the same when the relative humidity exceeds 50% in maritime aerosol models. The SSA for continental aerosols varies for core-shell mixing of water soluble

Practice of first aid in burn related injuries in a developing country.

PubMed

Fadeyibi, Idowu Olusegun; Ibrahim, Nasiru Akanmu; Mustafa, Ibrahim Akinwunmi; Ugburo, Andrew Omotayo; Adejumo, Adedeji Olusola; Buari, Adedayo

2015-09-01

First aid with cool running water reduces the severity of burn. Low level of knowledge of first aid in burns was shown in previous studies with few patients receiving first aid by water lavage. A study investigating the use of water lavage as first aid in patients presenting to hospital with burn in Lagos, Nigeria was carried out. Patients admitted to a University Teaching Hospital for treatment of burns were recruited for this prospective study. Data detailing demographics, scene and aetiology of burns, material used for first aid, who administered first aid, level of education and relationship of first-aider with patients, length of hospital stay, complications and outcome of treatment were collected and statistical analysis performed. 168 patients; 73 (43.4%) children and 95 (56.6%) adults were seen. Burns were sustained at home in 95 (74.2%) cases and outside in 33 (25.8%). Water lavage was used in 49 (29.2%) cases, raw eggs in 21 (12.5%), pap in 16 (9.5%) and other materials in 48.8%. 40 (23.8%) patients had not received any form of first aid at presentation. Patients that received no water first aid had higher complication rate (35.3% versus 18.4%) compared with those that had water first aid. The use of water first aid in burns was shown to reduce complication rate in this study. People should be educated on the efficacy of water first aid in pre-hospital care of burns. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Mixed convection of magnetohydrodynamic nanofluids inside microtubes at constant wall temperature

NASA Astrophysics Data System (ADS)

Moshizi, S. A.; Zamani, M.; Hosseini, S. J.; Malvandi, A.

2017-05-01

Laminar fully developed mixed convection of magnetohydrodynamic nanofluids inside microtubes at a constant wall temperature (CWT) under the effects of a variable directional magnetic field is investigated numerically. Nanoparticles are assumed to have slip velocities relative to the base fluid owing to thermophoretic diffusion (temperature gradient driven force) and Brownian diffusion (concentration gradient driven force). The no-slip boundary condition is avoided at the fluid-solid mixture to assess the non-equilibrium region at the fluid-solid interface. A scale analysis is performed to estimate the relative significance of the pertaining parameters that should be included in the governing equations. After the effects of pertinent parameters on the pressure loss and heat transfer enhancement were considered, the figure of merit (FoM) is employed to evaluate and optimize the thermal performance of heat exchange equipment. The results indicate the optimum thermal performance is obtained when the thermophoresis overwhelms the Brownian diffusion, which is for larger nanoparticles. This enhancement boosts when the buoyancy force increases. In addition, increasing the magnetic field strength and slippage at the fluid-solid interface enhances the thermal performance.

Public Entrepreneurs and the Adoption of Broad-Based Merit Aid beyond the Southeastern United States

ERIC Educational Resources Information Center

Ingle, William Kyle; Petroff, Ruth Ann

2013-01-01

The concentration of broad-based merit aid adoption in the southeastern United States has been well noted in the literature. However, there are states that have adopted broad-based merit aid programs outside of the Southeast. Guided by multiple theoretical frameworks, including innovation diffusion theory (e.g., Gray, 1973, 1994; Rogers, 2003),…

Diffusion of macromolecules in self-assembled cellulose/hemicellulose hydrogels.

PubMed

Lopez-Sanchez, Patricia; Schuster, Erich; Wang, Dongjie; Gidley, Michael J; Strom, Anna

2015-05-28

Cellulose hydrogels are extensively applied in many biotechnological fields and are also used as models for plant cell walls. We synthesised model cellulosic hydrogels containing hemicelluloses, as a biomimetic of plant cell walls, in order to study the role of hemicelluloses on their mass transport properties. Microbial cellulose is able to self-assemble into composites when hemicelluloses, such as xyloglucan and arabinoxylan, are present in the incubation media, leading to hydrogels with different nano and microstructures. We investigated the diffusivities of a series of fluorescently labelled dextrans, of different molecular weight, and proteins, including a plant pectin methyl esterase (PME), using fluorescence recovery after photobleaching (FRAP). The presence of xyloglucan, known to be able to crosslink cellulose fibres, confirmed by scanning electron microscopy (SEM) and (13)C NMR, reduced mobility of macromolecules of molecular weight higher than 10 kDa, reflected in lower diffusion coefficients. Furthermore PME diffusion was reduced in composites containing xyloglucan, despite the lack of a particular binding motif in PME for this polysaccharide, suggesting possible non-specific interactions between PME and this hemicellulose. In contrast, hydrogels containing arabinoxylan coating cellulose fibres showed enhanced diffusivity of the molecules studied. The different diffusivities were related to the architectural features found in the composites as a function of polysaccharide composition. Our results show the effect of model hemicelluloses in the mass transport properties of cellulose networks in highly hydrated environments relevant to understanding the role of hemicelluloses in the permeability of plant cell walls and aiding design of plant based materials with tailored properties.

17-N-Allylamino-17-Demethoxygeldanamycin in Treating Patients With Advanced Epithelial Cancer, Malignant Lymphoma, or Sarcoma

ClinicalTrials.gov

2013-02-06

AIDS-related Peripheral/Systemic Lymphoma; AIDS-related Primary CNS Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Chondrosarcoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Intraocular Lymphoma; Metastatic Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Metastatic Osteosarcoma; Nodal Marginal Zone B-cell Lymphoma; Ovarian Sarcoma; Primary Central Nervous System Non-Hodgkin Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Adult T-cell Leukemia/Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent Osteosarcoma; Recurrent Small Lymphocytic Lymphoma; Recurrent Uterine Sarcoma; Small Intestine Lymphoma; Splenic Marginal Zone Lymphoma; Stage IV Adult Burkitt Lymphoma; Stage IV Adult Diffuse Large Cell Lymphoma; Stage IV Adult Diffuse Mixed Cell Lymphoma; Stage IV Adult Diffuse Small Cleaved Cell Lymphoma; Stage IV Adult Hodgkin Lymphoma; Stage IV Adult Immunoblastic Large Cell Lymphoma; Stage IV Adult Lymphoblastic Lymphoma; Stage IV Adult Soft Tissue Sarcoma; Stage IV Adult T-cell Leukemia/Lymphoma; Stage IV Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IV Grade 1 Follicular Lymphoma; Stage IV Grade 2 Follicular Lymphoma; Stage IV Grade 3 Follicular Lymphoma; Stage IV Mantle Cell Lymphoma; Stage IV Marginal Zone Lymphoma; Stage IV Mycosis Fungoides/Sezary Syndrome; Stage IV Small

Gendered differences in AIDS and AIDS-related cause of death among youth with secondary education in South Africa, 2009-2011.

PubMed

De Wet, Nicole

2016-12-01

The prevalence of human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) is higher among females than males in Sub-Saharan Africa. Education is associated with better health outcomes. For this and other reasons, African countries have made a concerted effort to increase youth education rates. However, in South Africa males have lower secondary education rates than females, yet females have a higher prevalence of HIV/AIDS. This study examines if a gender disparity exists in AIDS mortality rates among youth with secondary education in South Africa. This study uses descriptive statistics and life table techniques. A sample of 4386 deaths of youth with secondary education is used. Of this total sample, 987 deaths were among males and 340 were among females with secondary education. This study shows that AIDS mortality is higher among females than males in South Africa. Males and females with secondary education have lower AIDS mortality than all males and females in the population, yet the rates are higher for females. Using cause-deleted life tables, the probability of youth dying from HIV/AIDS practically disappears for both males and females. Odds ratio calculations show that secondary education does not have a protective effect from AIDS mortality among male and female youth. Given the gendered difference in AIDS mortality among youth with secondary education, efforts to increase secondary education among males and further research into other factors exacerbating AIDS mortality among females with secondary education is needed in the country.

Nonconvective mixing of miscible ionic liquids.

PubMed

Frost, Denzil S; Machas, Michael; Perea, Brian; Dai, Lenore L

2013-08-13

Ionic liquids (ILs) are ionic compounds that are liquid at room temperature. We studied the spontaneous mixing behavior between two ILs, ethylammonium nitrate (EAN) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and observed notable phenomena. Experimental studies showed that the interface between the two ILs was unusually long-lived, despite the ILs being miscible with one another. Molecular dynamics (MD) simulations supported these findings and provided insight into the micromixing behavior of the ILs. We found that not only did the ions experience slow diffusion as they mix but also exhibited significant ordering into distinct regions. We suspect that this ordering disrupted concentration gradients in the direction normal to the interface, thus hindering diffusion in this direction and allowing the macroscopic interface to remain for long periods of time. Intermolecular interactions responsible for this behavior included the O-NH interaction between the EAN ions and the carbon chain-carbon chain interactions between the [BMIM](+) cations, which associate more strongly in the mixed state than in the pure IL state.

Control of Jet Noise Through Mixing Enhancement

NASA Technical Reports Server (NTRS)

Bridges, James; Wernet, Mark; Brown, Cliff

2003-01-01

The idea of using mixing enhancement to reduce jet noise is not new. Lobed mixers have been around since shortly after jet noise became a problem. However, these designs were often a post-design fix that rarely was worth its weight and thrust loss from a system perspective. Recent advances in CFD and some inspired concepts involving chevrons have shown how mixing enhancement can be successfully employed in noise reduction by subtle manipulation of the nozzle geometry. At NASA Glenn Research Center, this recent success has provided an opportunity to explore our paradigms of jet noise understanding, prediction, and reduction. Recent advances in turbulence measurement technology for hot jets have also greatly aided our ability to explore the cause and effect relationships of nozzle geometry, plume turbulence, and acoustic far field. By studying the flow and sound fields of jets with various degrees of mixing enhancement and subsequent noise manipulation, we are able to explore our intuition regarding how jets make noise, test our prediction codes, and pursue advanced noise reduction concepts. The paper will cover some of the existing paradigms of jet noise as they relate to mixing enhancement for jet noise reduction, and present experimental and analytical observations that support these paradigms.

[An investigation of psychological state at different stages of occupational AIDS exposure and related influencing factors in Nanning, China].

PubMed

Lin, Q; Ge, X M; Mo, J C; Li, S S; Chen, C C; Chen, S Y

2016-10-20

Objective: To investigate the changes in psychological state after occupational exposure in the AIDS occupational exposure population and related influencing factors, and to provide baseline data and a basis for related departments to conduct mental health prevention and intervention for personnel with occupational AIDS exposure. Methods: AIDS risk assessment was performed for all personnel with occupational AIDS exposure in 2014 in Nanning, China, and the Symptom Checklist - 90 (SCL - 90) psychological scale was used for psychological state evaluation at 24 hours, 1 week, and 3 months after occupational exposure in all persons who met the research criteria. Results: Most of the persons with occupational AIDS exposure came from secondary and tertiary hospitals (85%) , and nurses accounted for the highest percentage (78.3% ). The age ranged from 21 to 50 years, and the mean age was 31.02 ± 7.92 years. The persons with occupational AIDS exposure aged 20~29 years accounted for the highest percentage (51.6%) , and most persons (76.7%) graduated from junior colleges. Compared with the adult norm, there was significant increases in the total psychological score and the number of positive items after occupational exposure ( P <0.05). The scores of all items at 24 hours were significantly higher than those at the other time points, and the scores of all items gradually decreased over time ( F =227.24, 267.57, and 287.46, P <0.05). Compared with the adult norm, there were significant increases in the factor points at 24 hours and significant reductions in the factor points at 3 months ( P <0.05). Compared with those at 24 hours, the factor scores at 3 months decreased significantly ( P <0.05). Conclusion: Occupational AIDS exposure affects the mental status of related personnel, and the mental status at 24 hours after exposure is poor. Related departments should provide corresponding psychological counseling for the occupational exposure population at different exposure

Quantifying residual, eddy, and mean flow effects on mixing in an idealized circumpolar current

DOE PAGES

Wolfram, Phillip J.; Ringler, Todd D.

2017-07-13

Meridional diffusivity is assessed in this paper for a baroclinically unstable jet in a high-latitudeIdealized Circumpolar Current (ICC) using the Model for Prediction Across Scales-Ocean (MPAS-O) and the online Lagrangian In-situ Global High-performance particle Tracking (LIGHT) diagnostic via space-time dispersion of particle clusters over 120 monthly realizations of O(10 6) particles on 11 potential density surfaces. Diffusivity in the jet reaches values of O(6000 m 2 s -1) and is largest near the critical layer supporting mixing suppression and critical layer theory. Values in the vicinity of the shelf break are suppressed to O(100 m 2 s -1) due tomore » the presence of westward slope front currents. Diffusivity attenuates less rapidly with depth in the jet than both eddy velocity and kinetic energy scalings would suggest. Removal of the mean flow via high-pass filtering shifts the nonlinear parameter (ratio of the eddy velocity to eddy phase speed) into the linear wave regime by increasing the eddy phase speed via the depth-mean flow. Low-pass filtering, in contrast, quantifies the effect of mean shear. Diffusivity is decomposed into mean flow shear, linear waves, and the residual nonhomogeneous turbulence components, where turbulence dominates and eddy-produced filamentation strained by background mean shear enhances mixing, accounting for ≥ 80% of the total diffusivity relative to mean shear [O(100 m 2 s -1)], linear waves [O(1000 m 2 s -1)], and undecomposed full diffusivity [O(6000 m 2 s -1)]. Finally, diffusivity parameterizations accounting for both the nonhomogeneous turbulence residual and depth variability are needed.« less

Restoration of hearing by hearing aids: conventional hearing aids – implantable hearing aids – cochlear implants – auditory brainstem implants

PubMed Central

Leuwer, R.; Müller, J.

2005-01-01

Aim of this report is to explain the current concept of hearing restoration using hearing aids. At present the main issues of conventional hearing aids are the relative benefits of analogue versus digital devices and different strategies for the improvement of hearing in noise. Implantable hearing aids provide a better sound quality and less distortion. The lack of directional microphones is the major disadvantage of the partially implantable hearing aids commercially available. Two different clinical studies about fully implantable hearing aids have been started in 2004. One of the most-promising developments seems to be the electric-acoustic stimulation. PMID:22073051

Including scattering within the room acoustics diffusion model: An analytical approach.

PubMed

Foy, Cédric; Picaut, Judicaël; Valeau, Vincent

2016-10-01

Over the last 20 years, a statistical acoustic model has been developed to predict the reverberant sound field in buildings. This model is based on the assumption that the propagation of the reverberant sound field follows a transport process and, as an approximation, a diffusion process that can be easily solved numerically. This model, initially designed and validated for rooms with purely diffuse reflections, is extended in the present study to mixed reflections, with a proportion of specular and diffuse reflections defined by a scattering coefficient. The proposed mathematical developments lead to an analytical expression of the diffusion constant that is a function of the scattering coefficient, but also on the absorption coefficient of the walls. The results obtained with this extended diffusion model are then compared with the classical diffusion model, as well as with a sound particles tracing approach considering mixed wall reflections. The comparison shows a good agreement for long rooms with uniform low absorption (α = 0.01) and uniform scattering. For a larger absorption (α = 0.1), the agreement is moderate, due to the fact that the proposed expression of the diffusion coefficient does not vary spatially. In addition, the proposed model is for now limited to uniform diffusion and should be extended in the future to more general cases.

Assessing HIV and AIDS treatment safety and health-related quality of life among cohort of Malaysian patients: a discussion on methodological approach.

PubMed

Syed, Imran Ahmed; Syed Sulaiman, Syed Azhar; Hassali, Mohammad Azmi; Lee, Christopher K C

2015-10-01

Health-related quality of life (HRQoL) is increasingly recognized as an important outcome and as a complement to traditional biological end points of diseases such as mortality. Unless there is a complete cure available for HIV/AIDS, development and implementation of a reliable and valid cross cultural quality of life measure is necessary to assess not only the physical and medical needs of HIV/AIDS people, but their psychological, social, environmental, and spiritual areas of life. A qualitative exploration of HIV/AIDS patients' understanding, perceptions and expectations will be carried out with the help of semi structured interview guide by in depth interviews, while quantitative assessment of patient reported adverse drug reactions and their impact on health related quality of life will be carried out by using data collection tool comprising patient demographics, SF-12, Naranjo scale, and a clinical data sheet. The findings may serve as baseline QOL data of people living with HIV/AIDS in Malaysia and also a source data to aid construction of management plan to improve HIV/AIDS patients' QOL. It will also provide basic information about HIV/AIDS patients' perceptions, expectations and believes towards HIV/AIDS and its treatment which may help in designing strategies to enhance patients' awareness which in turn can help in addressing issues related to compliance and adherence. © 2013 John Wiley & Sons Ltd.

Response of radiation belt simulations to different radial diffusion coefficients

NASA Astrophysics Data System (ADS)

Drozdov, A.; Shprits, Y.; Subbotin, D.; Kellerman, A. C.

2013-12-01

Resonant interactions between Ultra Low Frequency (ULF) waves and relativistic electrons may violate the third adiabatic invariant of motion, which produces radial diffusion in the electron radiation belts. This process plays an important role in the formation and structure of the outer electron radiation belt and is important for electron acceleration and losses in that region. Two parameterizations of the resonant wave-particle interaction of electrons with ULF waves in the magnetosphere by Brautigam and Albert [2000] and Ozeke et al. [2012] are evaluated using the Versatile Electron Radiation Belt (VERB) diffusion code to estimate their relative effect on the radiation belt simulation. The period of investigation includes quiet time and storm time geomagnetic activity and is compared to data based on satellite observations. Our calculations take into account wave-particle interactions represented by radial diffusion transport, local acceleration, losses due to pitch-angle diffusion, and mixed diffusion. We show that the results of the 3D diffusion simulations depend on the assumed parametrization of waves. The differences between the simulations and potential missing physical mechanisms are discussed. References Brautigam, D. H., and J. M. Albert (2000), Radial diffusion analysis of outer radiation belt electrons during the October 9, 1990, magnetic storm, J. Geophys. Res., 105(A1), 291-309, doi:10.1029/1999JA900344 Ozeke, L. G., I. R. Mann, K. R. Murphy, I. J. Rae, D. K. Milling, S. R. Elkington, A. A. Chan, and H. J. Singer (2012), ULF wave derived radiation belt radial diffusion coefficients, J. Geophys. Res., 117, A04222, doi:10.1029/2011JA017463.

Modeling of inhomogeneous mixing of plasma species in argon-steam arc discharge

NASA Astrophysics Data System (ADS)

Jeništa, J.; Takana, H.; Uehara, S.; Nishiyama, H.; Bartlová, M.; Aubrecht, V.; Murphy, A. B.

2018-01-01

This paper presents numerical simulation of mixing of argon- and water-plasma species in an argon-steam arc discharge generated in a thermal plasma generator with the combined stabilization of arc by axial gas flow (argon) and water vortex. The diffusion of plasma species itself is described by the combined diffusion coefficients method in which the coefficients describe the diffusion of argon ‘gas,’ with respect to water vapor ‘gas.’ Diffusion processes due to the gradients of mass density, temperature, pressure, and an electric field have been considered in the model. Calculations for currents 150-400 A with 15-22.5 standard liters per minute (slm) of argon reveal inhomogeneous mixing of argon and oxygen-hydrogen species with the argon species prevailing near the arc axis. All the combined diffusion coefficients exhibit highly nonlinear distribution of their values within the discharge, depending on the temperature, pressure, and argon mass fraction of the plasma. The argon diffusion mass flux is driven mainly by the concentration and temperature space gradients. Diffusions due to pressure gradients and due to the electric field are of about 1 order lower. Comparison with our former calculations based on the homogeneous mixing assumption shows differences in temperature, enthalpy, radiation losses, arc efficiency, and velocity at 400 A. Comparison with available experiments exhibits very good qualitative and quantitative agreement for the radial temperature and velocity profiles 2 mm downstream of the exit nozzle.

First aid: level of knowledge of relatives and bystanders in emergency situations.

PubMed

Tomruk, Onder; Soysal, Suna; Gunay, Turkan; Cimrin, Arif H

2007-01-01

Bystanders who are able to provide immediate first aid to patients who require emergency care can make a big difference in the outcome. Thus, first-aid training should be made available to as many people as possible. The aims of this study were to assess the level of first-aid knowledge among bystanders in emergency situations and to identify factors that affected this level of knowledge. At Dokuz Eylul University Emergency Service between February 1 and February 15, 2002, 318 bystanders were given a questionnaire. The first part of the questionnaire was concerned with demographic characteristics and factors that would affect first-aid knowledge level. The second part consisted of 16 multiple choice questions about first aid. Bystanders answered an average of 7.16+/-3.14 questions correctly. Bystanders who had graduated from a university, were health care personnel, had taken a first-aid course, had a first-aid certificate, or had a driver's license were considered to be more successful.

Interplay Between Hiv/aids Epidemics and Demographic Structures Based on Sexual Contact Networks

NASA Astrophysics Data System (ADS)

Bai, Wen-Jie; Zhou, Tao; Wang, Bing-Hong

In this article, we propose a network spreading model for HIV epidemics, wherein each individual is represented by a node of the transmission network and the edges are the connections between individuals along which the infection may spread. The sexual activity of each individual, measured by its degree, is not homogeneous but obeys a power-law distribution. Due to the heterogeneity of activity, the infection can persistently exist at a very low prevalence, which has been observed in the real data but cannot be illuminated by previous models with homogeneous mixing hypothesis. The model displays a clear picture of hierarchical spread: In the early stage the infection is adhered to these high-risk persons, and then, diffuses toward low-risk population. Furthermore, we find that to reduce the risky behaviors is much more effective in the fight against HIV/AIDS rather than the antiretroviral drug therapies. The prediction results show that the development of epidemics can be roughly categorized into three patterns for different countries, and the pattern of a given country is mainly determined by the average sex-activity and transmission probability per sexual partner. In most cases, the effect of HIV epidemics on demographic structure is very small. However, for some extremely countries, like Botswana, the number of sex-active people can be depressed to nearly a half by AIDS.

Computer-aided diagnosis of alcoholism-related EEG signals.

PubMed

Acharya, U Rajendra; S, Vidya; Bhat, Shreya; Adeli, Hojjat; Adeli, Amir

2014-12-01

Alcoholism is a severe disorder that affects the functionality of neurons in the central nervous system (CNS) and alters the behavior of the affected person. Electroencephalogram (EEG) signals can be used as a diagnostic tool in the evaluation of subjects with alcoholism. The neurophysiological interpretation of EEG signals in persons with alcoholism (PWA) is based on observation and interpretation of the frequency and power in their EEGs compared to EEG signals from persons without alcoholism. This paper presents a review of the known features of EEGs obtained from PWA and proposes that the impact of alcoholism on the brain can be determined by computer-aided analysis of EEGs through extracting the minute variations in the EEG signals that can differentiate the EEGs of PWA from those of nonaffected persons. The authors advance the idea of automated computer-aided diagnosis (CAD) of alcoholism by employing the EEG signals. This is achieved through judicious combination of signal processing techniques such as wavelet, nonlinear dynamics, and chaos theory and pattern recognition and classification techniques. A CAD system is cost-effective and efficient and can be used as a decision support system by physicians in the diagnosis and treatment of alcoholism especially those who do not specialize in alcoholism or neurophysiology. It can also be of great value to rehabilitation centers to assess PWA over time and to monitor the impact of treatment aimed at minimizing or reversing the effects of the disease on the brain. A CAD system can be used to determine the extent of alcoholism-related changes in EEG signals (low, medium, high) and the effectiveness of therapeutic plans. Copyright © 2014 Elsevier Inc. All rights reserved.

Computational analysis of electrokinetically driven flow mixing in microchannels with patterned blocks

NASA Astrophysics Data System (ADS)

Chang, C.-C.; Yang, R.-J.

2004-04-01

Electroosmotic flow in microchannels is restricted to low Reynolds number regimes characterized by extremely weak inertia forces and laminar flow. Consequently, the mixing of different species occurs primarily through diffusion, and hence cannot readily be achieved within a short mixing channel. The current study presents a numerical investigation of electrokinetically driven flow mixing in microchannels with various numbers of incorporated patterned rectangular blocks. Furthermore, a novel approach is introduced which patterns heterogeneous surfaces on the upper faces of these rectangular blocks in order to enhance species mixing. The simulation results confirm that the introduction of rectangular blocks within the mixing channel slightly enhances species mixing by constricting the bulk flow, hence creating a stronger diffusion effect. However, it is noted that a large number of blocks and hence a long mixing channel are required if a complete mixing of the species is to be obtained. The results also indicate that patterning heterogeneous upper surfaces on the rectangular blocks is an effective means of enhancing the species mixing. It is shown that increasing the magnitude of the heterogeneous surface zeta potential enables a reduction in the mixing channel length and an improved degree of mixing efficiency.

Perceptual Influence of Ugandan Biology Students' Understanding of HIV/AIDS

NASA Astrophysics Data System (ADS)

Mutonyi, Harriet; Nashon, Samson; Nielsen, Wendy S.

2010-08-01

In Uganda, curbing the spread of HIV/AIDS has largely depended on public and private media messages about the disease. Media campaigns based on Uganda’s cultural norms of communication are metaphorical, analogical and simile-like. The topic of HIV/AIDS has been introduced into the Senior Three (Grade 11) biology curriculum in Uganda. To what extent do students’ pre-conceptions of the disease, based on these media messages influence students’ development of conceptual understanding of the disease, its transmission and prevention? Of significant importance is the impact the conceptions students have developed from the indirect media messages on classroom instruction on HIV/AIDS. The study is based in a theoretical framework of conceptual change in science learning. An interpretive case study to determine the impact of Ugandan students’ conceptions or perceptions on classroom instruction about HIV/AIDS, involving 160 students aged 15-17, was conducted in four different Ugandan high schools: girls boarding, boys boarding, mixed boarding, and mixed day. Using questionnaires, focus group discussions, recorded biology lessons and informal interviews, students’ preconceptions of HIV/AIDS and how these impact lessons on HIV/AIDS were discerned. These preconceptions fall into four main categories: religious, political, conspiracy and traditional African worldviews. Results of data analysis suggest that students’ prior knowledge is persistent even after biology instructions. This has implications for current teaching approaches, which are mostly teacher-centred in Ugandan schools. A rethinking of the curriculum with the intent of offering science education programs that promote understanding of the science of HIV/AIDS as opposed to what is happening now—insensitivity to misconceptions about the disease—is needed.

Microscopic diffusion anisotropy in the human brain: Age-related changes.

PubMed

Lawrenz, Marco; Brassen, Stefanie; Finsterbusch, Jürgen

2016-11-01

The fractional anisotropy (FA) that can be derived from diffusion tensor imaging (DTI), is ambiguous because it not only depends on the tissue microstructure but also on the axon or fiber orientation distribution within a voxel. Measures of the microscopic diffusion anisotropy, like the microscopic anisotropy index (MA) that can be determined with so-called double-wave-vector (DWV) or double diffusion encoding (DDE) imaging, are independent of this orientation distribution and, thus, offer a more direct and undisguised access to the tissue structure on a cellular or microscopic scale. In this study, FA and MA measurements were performed in a group of aged (>60y), healthy volunteers and compared to the data obtained recently for a group of young (<33y), healthy volunteers to reveal age-related differences. The coefficients-of-variation (CV) determined for the aged group were considerably lower for MA than for FA in average and in most of the 16 ROIs analyzed due to lower between-subject variations of MA. FA differences between the young and the aged group were in line with previous DTI studies. MA was also decreased in the aged group but in more of the 16 ROIs and with a higher significance. Furthermore, MA differences were also observed in frontal brain regions containing fiber crossings that did not reveal significant FA differences, i.e. MA seems to provide a better sensitivity to detect microstructural changes in such regions. In some non-cortical gray matter structures like the putamen, FA was increased but MA was decreased in the aged group which could indicate a coherent fiber orientation in the aged group related to the loss of crossing or fanning fibers. In conclusion, MA not only could improve the detectability of differences of the tissue microstructure but, in conjunction with FA, could also help to identify the underlying changes. Copyright © 2016 Elsevier Inc. All rights reserved.

[Change trend of HIV/AIDS related risk factors and influencing factors among men who have sex with men in Yunnan, 2010-2013].

PubMed

Song, Lijun; Mei, Jingyuan; Lu, Jiyun; Fu, Liru; Li, Xuehua; Niu, Jin; Xiao, Minyang; Zhang, Zuyang; Lu, Ran; Luo, Hongbing

2015-02-01

To understand the change trend of the awareness rate of HIV/AIDS related knowledge, risk behaviors among men who have sex with men (MSM) in Yunnan and the factors influencing their condom use, and evaluate the effect of comprehensive intervention. The data about the MSM's demographic information, HIV/AIDS related knowledge awareness, and sex behavior, condom use, drug use and intervention receiving were obtained from AIDS sentinel surveillance among MSM in Yunnan province during 2010-2013 to conduct change trend and influencing factor analysis. A total of 9 073 MSM were surveyed. The awareness rate of the HIV/AIDS related knowledge, homosexual behavior and condom use rate increased year by year (P < 0.01). The condom use rate was lower in heterosexual behavior, and the drug use rate and sexually transmitted disease prevalence declined with year (P < 0.01). Multivariate logistic regression analysis indicated that cohabiting, low awareness of HIV/AIDS related knowledge, being from other provinces, local residence for <1 year, low education level, receiving no intervention, frequent anal sex and receiving no HIV/AIDS detection were the risk factors influencing persistent condom use among MSM. The effect of HIV/AIDS comprehensive intervention was observed after 4 years implantation, but most of the index were at low level. More attention should be paid to the intervention among MSM with cohabiting habit, low education level, frequent anal sex, and heterosexual sex. It is necessary to expand intervention coverage, strengthen HIV test and promote condom use among MSM.

Comparison of block and event-related experimental designs in diffusion-weighted functional MRI.

PubMed

Williams, Rebecca J; McMahon, Katie L; Hocking, Julia; Reutens, David C

2014-08-01

To compare diffusion-weighted functional magnetic resonance imaging (DfMRI), a novel alternative to the blood oxygenation level-dependent (BOLD) contrast, in a functional MRI experiment. Nine participants viewed contrast reversing (7.5 Hz) black-and-white checkerboard stimuli using block and event-related paradigms. DfMRI (b = 1800 mm/s(2)) and BOLD sequences were acquired. Four parameters describing the observed signal were assessed: percent signal change, spatial extent of the activation, the Euclidean distance between peak voxel locations, and the time-to-peak of the best fitting impulse response for different paradigms and sequences. The BOLD conditions showed a higher percent signal change relative to DfMRI; however, event-related DfMRI showed the strongest group activation (t = 21.23, P < 0.0005). Activation was more diffuse and spatially closer to the BOLD response for DfMRI when the block design was used. DfMRIevent showed the shortest TTP (4.4 ± 0.88 sec). The hemodynamic contribution to DfMRI may increase with the use of block designs. © 2013 Wiley Periodicals, Inc.

Limited Reach: The Role of Mission and Institutional Aid in Supporting Minority Students

ERIC Educational Resources Information Center

Finger, Mary Catherine

2013-01-01

This study uses a mixed methods research design to explore the relationship between institutional financial aid practice and graduation rates at a subset of private, non-profit four-year colleges and universities and explores how institutions prioritize allocations to financial aid within the framework of institutional mission, culture, and…

Aiding flow Thermo-Solutal Convection in Porous Cavity: ANN approach

NASA Astrophysics Data System (ADS)

Jafer Kazi1, Mohammed; Ameer Ahamad, N.; Yunus Khan, T. M.

2017-08-01

The transfer of thermal energy along with the diffusion of mass is common phenomenon that occurs in nature. The thermos-solutal convection in porous medium arises due to combined effect of diffusion of heat as well as mass inside the domain. The density variation of fluid due to absorbed heat at one end of porous cavity leads to fluid movement which in turn initiates the heat transfer. The mass diffusion inside the porous regime occurs due to concentration difference between two ends of cavity. Generally this phenomenon is studied with the help of numerical methods but current work emphasis the successful usage of artificial neural network in predicting the thermos-solutal convection of aiding flow in porous medium.

AIDS-Related Knowledge, Attitudes, Beliefs, and Behaviors in Los Angeles County

DTIC Science & Technology

1991-01-01

information: results of logistic regression ............................. 76 A.7. Predictors of who uses pamphlets/ brochures as a major source of AIDS...often (by 60 percent of the respondents). Brochures and pamphlets about AIDS from local, state, or federal agencies were mentioned by 25 percent of all...8217 KNOWLEDGE OF INFORMATION SOURCES ABOUT AIDS Single Most Any Trustworthy Source Mention a Mention TV/radio 73 19 Magazines/newspapers 59 7 Brochures

Diffusion-Tensor Imaging Findings and Cognitive Function Following Hospitalized Mixed-Mechanism Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

PubMed

Oehr, Lucy; Anderson, Jacqueline

2017-11-01

To undertake a systematic review and meta-analysis of the relationship between microstructural damage and cognitive function after hospitalized mixed-mechanism (HMM) mild traumatic brain injury (mTBI). PsycInfo, EMBASE, and MEDLINE were used to find relevant empirical articles published between January 2002 and January 2016. Studies that examined the specific relationship between diffusion tensor imaging (DTI) and cognitive test performance were included. The final sample comprised previously medically and psychiatrically healthy adults with HMM mTBI. Specific data were extracted including mTBI definitional criteria, descriptive statistics, outcome measures, and specific results of associations between DTI metrics and cognitive test performance. Of the 248 original articles retrieved and reviewed, 8 studies met all inclusion criteria and were included in the meta-analysis. The meta-analysis revealed statistically significant associations between reduced white matter integrity and poor performance on measures of attention (fractional anisotropy [FA]: d=.413, P<.001; mean diffusivity [MD]: d=-.407, P=.001), memory (FA: d=.347, P<.001; MD: d=-.568, P<.001), and executive function (FA: d=.246, P<.05), which persisted beyond 1 month postinjury. The findings from the meta-analysis provide clear support for an association between in vivo markers of underlying neuropathology and cognitive function after mTBI. Furthermore, these results demonstrate clearly for the first time that in vivo markers of structural neuropathology are associated with cognitive dysfunction within the domains of attention, memory, and executive function. These findings provide an avenue for future research to examine the causal relationship between mTBI-related neuropathology and cognitive dysfunction. Furthermore, they have important implications for clinical management of patients with mTBI because they provide a more comprehensive understanding of factors that are associated with cognitive

HIV-related stigma acting as predictors of unemployment of people living with HIV/AIDS.

PubMed

Liu, Ying; Canada, Kelli; Shi, Kan; Corrigan, Patrick

2012-01-01

Obtaining employment is an important part of recovery for many people living with HIV/AIDS (PLHA). However, this population often faces barriers in their attempt to reenter the workplace. One potential barrier lies in the decision-making of employers. Little is known about what influences employers' decision to hire PLHA. The current paper addresses this gap with findings from 156 quantitative interviews with employers across Chicago, Beijing, and Hong Kong regarding the hiring of people with HIV/AIDS. Hierarchical regression analysis showed that both fear of contagion and perceived incompetence are important factors in employers' decision to interview even after controlling for variables related to the employers' business size, their education level, and the provision of health benefits. These two variables accounted for 42% of the variance in employers' decision to interview. Implications of these findings are considered for better understanding of HIV-related employment stigma and further intervention for employing PLHA.

Optical (diffuse reflectance) and Mossbauer spectroscopic study of nontronite and related Fe-bearing smectites

USGS Publications Warehouse

Sherman, David M.; Vergo, N.

1988-01-01

Near-ultraviolet to near-infrared optical (diffuse reflectance) spectra of several nontronites and related Fe-bearing smectites [(Fe2+,Fe3+)-bearing saponite and (Fe2+,Fe3+)-bearing montmorillonite] are presented and interpreted. Mossbauer spectra at 298 K are also presented to help interpret the optical spectra. The optical spectra of nontronites are dominated by the ligand field transitions of Fe3+ in octahedral coordination sites. In addition to the ligand field transitions of single Fe3+ cations, a broad absorption band centered near 22000 cm-1 is observed that may be due to the simultaneous excitation of two Fe3+ cations to the 4T1g (4G) state. Alternatively, this band may represent excitations to the 2A2g and 2T1g ligand field states. For most samples, the amount of tetrahedrally coordinated Fe3+ was below that detectable by Mossbauer spectroscopy (1-3% of total Fe). However, the optical spectra of all of the nontronites show an absorption band near 23000 cm-1. This band is assigned to the 6A1 ??? 4E,4A1 transition of tetrahedrally coordinated Fe3+. The optical spectra of mixed-valence Fe-bearing smectites show a broad absorption band at 14000-15000 cm-1 owing to Fe2+ ??? Fe3+ charge transfer. -from Authors

Care centre visits to married people living with HIV: an indicator for measuring AIDS-related stigma & discrimination.

PubMed

Green, D A; Devi, S; Paulraj, L S

2007-08-01

We tested whether observation of the presence and relationship of attendants (i.e. those that accompany upon admission) and visitors to a sample of 230 (128 male, 102 female) married HIV-positive people in an HIV care centre provides an indicator of caregiving, AIDS-related stigma and discrimination. Sensitivity to gender, location (urban vs. rural), age (<35 yrs vs. >35) and source of infection (spouse vs. non-spouse) were factors considered to modulate AIDS-related stigma and assess discrimination. HIV-positive people were accompanied by their spouse (53%), mother (14%), father (7%), with only 7% attending alone. Immediate family most commonly accompanied on admission (80%), but visitors were mainly from the 'extended' family (32%) with many receiving no visitors (48%). Females (11%) were more likely than males to attend alone (11% vs. 4%; p<0.05). No effect of location, age or infector was obtained. Females were more likely to be visited by their mother (14% vs. 6%; p<0.01) and non-immediate family (39% vs. 27%; p<0.05) than males were. In contrast, fathers (0% vs. 6%; p <0.05) and spouses were less likely (3% vs. 10%; p<0.05) to visit females than males. No effect of location or age upon visitation was obtained. Non-spouse infected persons were less likely than spouse-infected to be visited by their spouse (3% vs. 10%; p<0.05) but more likely to receive 'extended' family visitation (43% vs. 24%; p<0.01). Spouse-infected persons had a higher rate of no visitors than persons not infected by their spouse (54% vs. 40%; p<0.05). Observation of the presence and relationship of attendants and visitors to HIV-positive people has potential as an indicator of caregiving AIDS-related stigma and discrimination. The measure appears particularly sensitive to the gender of the HIV-positive person. Such a measure may aid healthcare professionals to focus resources such as relational counselling upon the family and close friends of people experiencing AIDS-related stigma and

Load Diffusion in Composite and Smart Structures

NASA Technical Reports Server (NTRS)

Horgan, C. O.

2003-01-01

The research carried out here builds on our previous NASA supported research on the general topic of edge effects and load diffusion in composite structures. Further fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for the multi-functional large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Some specific problems recently considered were those of end effects in smart materials and structures, study of the stress response of pressurized linear piezoelectric cylinders for both static and steady rotating configurations, an analysis of the effect of pre-stressing and pre-polarization on the decay of end effects in piezoelectric solids and investigation of constitutive models for hardening rubber-like materials. Our goal in the study of load diffusion is the development of readily applicable results for the decay lengths in terms of non-dimensional material and geometric parameters. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses. The decay behavior of stresses and other field quantities provides a significant aid towards this process. The analysis is also amenable to parameter study with a large parameter space and should be useful in structural tailoring studies. Special purpose analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and in assessing results from general purpose finite element analyses. For example, a rational basis is needed in choosing where to use three-dimensional to two-dimensional transition finite elements in analyzing stiffened plates and shells. The decay behavior of stresses and other field quantities furnished by

AIDS: Secretions and Implications for Nursing Care-Givers.

DTIC Science & Technology

1992-05-06

addition, infected cells may be found in many different organs, often at the same time: the brain, lymph nodes , thymus gland, bone marrow, lungs, skin...symptomatic disease with diffuse non-malignant lymph node hypertrophy. Aside from these symptoms of lymphadenopathy, patients are typically healthy...a person physically and mentally crippled. AIDS dementia complex (ADC) or subacute HIV encephalopathy, primary lymphomas, toxoplasmosis , cryptococcal

AIDS-related Kaposi sarcoma: findings on thallium-201 scintigraphy

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

Lee, V.W.; Rosen, M.P.; Baum, A.

1988-12-01

No simple, noninvasive method is available for evaluating extracutaneous Kaposi sarcoma in AIDS patients or for following the tumor's response to treatment. We report our preliminary experience with thallium-201 scintigraphy in nine AIDS patients with proved Kaposi sarcoma. Eight of the nine had abnormal uptake of the radionuclide in skin, lymph nodes, oral cavity, vagina, and lungs. Only four of the nine had cutaneous Kaposi sarcoma at the time of scanning. All cutaneous and mucosal lesions were thallium avid. Two of the six patients with thallium-avid nodes underwent nodal biopsy. Both biopsies confirmed the diagnosis of Kaposi sarcoma. Cutaneous Kaposimore » sarcoma developed later in one of these patients, showing the efficacy of thallium scintigraphy for the early detection of extracutaneous lesions. These preliminary results show thallium avidity in Kaposi sarcoma involving the skin and various extracutaneous sites (lymph nodes, lung, mucosa, and vagina). Thallium scintigraphy is a potentially useful procedure for detecting extracutaneous Kaposi sarcoma in AIDS patients.« less

Improvements in Mixing Time and Mixing Uniformity in Devices Designed for Studies of Protein Folding Kinetics

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

Yao, Shuhuai; Bakajin, Olgica

2007-08-01

Using a microfluidic laminar flow mixer designed for studies of protein folding kinetics, we demonstrate a mixing time of 1 +/- 1 micros with sample consumption on the order of femtomoles. We recognize two limitations of previously proposed designs: (1) size and shape of the mixing region, which limits mixing uniformity and (2) the formation of Dean vortices at high flow rates, which limits the mixing time. We address these limitations by using a narrow shape-optimized nozzle and by reducing the bend of the side channel streamlines. The final design, which combines both of these features, achieves the best performance.more » We quantified the mixing performance of the different designs by numerical simulation of coupled Navier-Stokes and convection-diffusion equations and experiments using fluorescence resonance energy-transfer (FRET)-labeled DNA.« less

Double-diffusive instabilities in ancient seawater

NASA Astrophysics Data System (ADS)

Pawlowicz, Rich; Scheifele, Ben; Zaloga, Artem; Wuest, Alfred; Sommer, Tobias

2015-04-01

Powell Lake, British Columbia, Canada is a geothermally heated lake about 350m deep with a saline lower layer that was isolated from the ocean by coastal uplift about 11000 years ago, after the last ice age. Careful temperature and conductivity profiling measurements show consistent, stable, and spatially/temporally coherent steps resulting from double-diffusive processes in certain ranges of depth, vertically interspersed with other depth ranges where these signatures are not present. These features are quasi-stable for at least several years. Although molecular diffusion has removed about half the salt from the deepest waters and biogeochemical processes have slightly modified the water composition, the lack of tidal processes and shear-driven mixing, as well as an accurate estimate of heat flux from both sediment heat flux measurements and gradient measurements in a region not susceptible to diffusive instabilities, makes this a unique geophysical laboratory to study double diffusion. Here we present a detailed picture of the structure of Powell Lake and its double-diffusive stair cases, and suggest shortcomings with existing parameterizations for fluxes through such staircases.

Ultrafast lithium diffusion in bilayer graphene

NASA Astrophysics Data System (ADS)

Kühne, Matthias; Paolucci, Federico; Popovic, Jelena; Ostrovsky, Pavel M.; Maier, Joachim; Smet, Jurgen H.

2017-09-01

Solids that simultaneously conduct electrons and ions are key elements for the mass transfer and storage required in battery electrodes. Single-phase materials with a high electronic and high ionic conductivity at room temperature are hard to come by, and therefore multiphase systems with separate ion and electron channels have been put forward instead. Here we report on bilayer graphene as a single-phase mixed conductor that demonstrates Li diffusion faster than in graphite and even surpassing the diffusion of sodium chloride in liquid water. To measure Li diffusion, we have developed an on-chip electrochemical cell architecture in which the redox reaction that forces Li intercalation is localized only at a protrusion of the device so that the graphene bilayer remains unperturbed from the electrolyte during operation. We performed time-dependent Hall measurements across spatially displaced Hall probes to monitor the in-plane Li diffusion kinetics within the graphene bilayer and measured a diffusion coefficient as high as 7 × 10-5 cm2 s-1.

Axial diffusivity of the corona radiata correlated with ventricular size in adult hydrocephalus.

PubMed

Cauley, Keith A; Cataltepe, Oguz

2014-07-01

Hydrocephalus causes changes in the diffusion-tensor properties of periventricular white matter. Understanding the nature of these changes may aid in the diagnosis and treatment planning of this relatively common neurologic condition. Because ventricular size is a common measure of the severity of hydrocephalus, we hypothesized that a quantitative correlation could be made between the ventricular size and diffusion-tensor changes in the periventricular corona radiata. In this article, we investigated this relationship in adult patients with hydrocephalus and in healthy adult subjects. Diffusion-tensor imaging metrics of the corona radiata were correlated with ventricular size in 14 adult patients with acute hydrocephalus, 16 patients with long-standing hydrocephalus, and 48 consecutive healthy adult subjects. Regression analysis was performed to investigate the relationship between ventricular size and the diffusion-tensor metrics of the corona radiata. Subject age was analyzed as a covariable. There is a linear correlation between fractional anisotropy of the corona radiata and ventricular size in acute hydrocephalus (r = 0.784, p < 0.001), with positive correlation with axial diffusivity (r = 0.636, p = 0.014) and negative correlation with radial diffusivity (r = 0.668, p = 0.009). In healthy subjects, axial diffusion in the periventricular corona radiata is more strongly correlated with ventricular size than with patient age (r = 0.466, p < 0.001, compared with r = 0.058, p = 0.269). Axial diffusivity of the corona radiata is linearly correlated with ventricular size in healthy adults and in patients with hydrocephalus. Radial diffusivity of the corona radiata decreases linearly with ventricular size in acute hydrocephalus but is not significantly correlated with ventricular size in healthy subjects or in patients with long-standing hydrocephalus.

Phase I study of 2'-3'-dideoxyinosine administered orally twice daily to patients with AIDS or AIDS-related complex and hematologic intolerance to zidovudine.

PubMed

Connolly, K J; Allan, J D; Fitch, H; Jackson-Pope, L; McLaren, C; Canetta, R; Groopman, J E

1991-11-01

To evaluate the safety and hematologic tolerance of 2'-3'-dideoxyinosine (didanosine, ddI) in subjects with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex and prior hematologic intolerance to zidovudine. A Phase I trial with two dose groups at a single-center, university-affiliated hospital ambulatory care center. Of 30 subjects enrolled, 21 had AIDS and nine had AIDS-related complex. All had CD4 lymphocyte counts less than 0.2 x 10(9)/L at entry. Didanosine was administered orally twice daily at a total daily dose of 750 mg or 1,500 mg for 12 weeks. Subjects who completed the 12-week study continued to receive ddI at the lower dose. All subjects were monitored for toxicity. Virologic and immunologic response markers were also measured. For the group as a whole, there was no significant decrease in mean hemoglobin level or leukocyte or platelet counts. The dose-limiting toxicity was peripheral neuropathy. Other significant toxicities included pancreatitis and hypocalcemia. Uric acid elevations were common but were without clinical consequence. A sustained decrease in serum p24 antigen of at least 50% was noted in 42% of subjects who were p24 antigen-positive at entry. The mean CD4 lymphocyte count showed an initial increase that was not sustained over the 12-week study. All subjects remained anergic to skin testing. Didanosine is well tolerated hematologically in some patients with prior significant hematologic intolerance to zidovudine. The toxicity profile for ddI differs from that of zidovudine and includes peripheral neuropathy and pancreatitis. Changes in CD4 lymphocyte number and HIV p24 antigen levels in some patients suggest antiviral activity of ddI in this population.

Effects of Buoyancy on Laminar, Transitional, and Turbulent Gas Jet Diffusion Flames

NASA Technical Reports Server (NTRS)

Bahadori, M. Yousef; Stocker, Dennis P.; Vaughan, David F.; Zhou, Liming; Edelman, Raymond B.

1993-01-01

Gas jet diffusion flames have been a subject of research for many years. However, a better understanding of the physical and chemical phenomena occurring in these flames is still needed, and, while the effects of gravity on the burning process have been observed, the basic mechanisms responsible for these changes have yet to be determined. The fundamental mechanisms that control the combustion process are in general coupled and quite complicated. These include mixing, radiation, kinetics, soot formation and disposition, inertia, diffusion, and viscous effects. In order to understand the mechanisms controlling a fire, laboratory-scale laminar and turbulent gas-jet diffusion flames have been extensively studied, which have provided important information in relation to the physico-chemical processes occurring in flames. However, turbulent flames are not fully understood and their understanding requires more fundamental studies of laminar diffusion flames in which the interplay of transport phenomena and chemical kinetics is more tractable. But even this basic, relatively simple flame is not completely characterized in relation to soot formation, radiation, diffusion, and kinetics. Therefore, gaining an understanding of laminar flames is essential to the understanding of turbulent flames, and particularly fires, in which the same basic phenomena occur. In order to improve and verify the theoretical models essential to the interpretation of data, the complexity and degree of coupling of the controlling mechanisms must be reduced. If gravity is isolated, the complication of buoyancy-induced convection would be removed from the problem. In addition, buoyant convection in normal gravity masks the effects of other controlling parameters on the flame. Therefore, the combination of normal-gravity and microgravity data would provide the information, both theoretical and experimental, to improve our understanding of diffusion flames in general, and the effects of gravity on the

Living with HIV/AIDS in School.

ERIC Educational Resources Information Center

Sedletter, 1993

1993-01-01

This newsletter article is concerned with understanding what schools can and must do to sustain life in the age of human immunodeficiency virus and Acquired Immune Deficiency Syndrome (HIV/AIDS). The article looks at the incidence of AIDS and reviews legislation related to AIDS infection and school attendance. School policy as it relates to…

Dip-coating of nano-sized CeO2 on SiC membrane and its effect on thermal diffusivity.

PubMed

Park, Jihye; Jung, Miewon

2014-05-01

CeO2-SiC mixed composite membrane was fabricated with porous SiC ceramic and cerium oxide powder synthesized by sol-gel process. This CeO2-SiC membrane and SiC membrane which is made by the purified SiC ceramic were pressed and sintered in Ar atmosphere. And then, the SiC membrane was dip-coated by cerium oxide precursor sol solution and heat-treated in air. The surface morphology, particle size, porosity and structure analysis of the mixing and dip-coating SiC membrane were monitored by FE-SEM and X-ray diffraction analysis. Surface area, pore volume and pore diameter were determined by BET instrument. Thermal diffusivity was measured by laser flash method with increasing temperature. The relation between porosity and thermal diffusivity from different preparation process has been discussed on this study.

Transport and fluctuation-dissipation relations in asymptotic and preasymptotic diffusion across channels with variable section.

PubMed

Forte, Giuseppe; Cecconi, Fabio; Vulpiani, Angelo

2014-12-01

We study the asymptotic and preasymptotic diffusive properties of Brownian particles in channels whose section varies periodically in space. The effective diffusion coefficient D(eff) is numerically determined by the asymptotic behavior of the root mean square displacement in different geometries, considering even cases of steep variations of the channel boundaries. Moreover, we compared the numerical results to the predictions from the various corrections proposed in the literature to the well known Fick-Jacobs approximation. Building an effective one-dimensional equation for the longitudinal diffusion, we obtain an approximation for the effective diffusion coefficient. Such a result goes beyond a perturbation approach, and it is in good agreement with the actual values obtained by the numerical simulations. We discuss also the preasymptotic diffusion which is observed up to a crossover time whose value, in the presence of strong spatial variation of the channel cross section, can be very large. In addition, we show how the Einstein's relation between the mean drift induced by a small external field and the mean square displacement of the unperturbed system is valid in both asymptotic and preasymptotic regimes.

Concise evaluation of decision aids.

PubMed

Stalmeier, Peep F M; Roosmalen, Marielle S

2009-01-01

Decision aids purport to help patients make treatment related choices. Several instruments exist to evaluate decision aids. Our aim is to compare the responsiveness of several instruments. Two different decision aids were randomized in patients at high risk for breast and ovarian cancer. Treatment choices were between prophylactic surgery and screening. Effect sizes were calculated to compare the responsiveness of the measures. One decision aid was randomized in 390 women, the other in 91 ensuing mutation carriers. Three factors were identified related to Information, Well-being and Decision Making. Within each factor, single item measures were as responsive as multi-item measures. Four single items, 'the amount of information received for decision making,' 'strength of preference,' 'I weighed the pros and cons,' and 'General Health,' were adequately responsive to the decision aids. These items might be considered for inclusion in questionnaires to evaluate decision aids.

Scalar mixing and strain dynamics methodologies for PIV/LIF measurements of vortex ring flows

NASA Astrophysics Data System (ADS)

Bouremel, Yann; Ducci, Andrea

2017-01-01

Fluid mixing operations are central to possibly all chemical, petrochemical, and pharmaceutical industries either being related to biphasic blending in polymerisation processes, cell suspension for biopharmaceuticals production, and fractionation of complex oil mixtures. This work aims at providing a fundamental understanding of the mixing and stretching dynamics occurring in a reactor in the presence of a vortical structure, and the vortex ring was selected as a flow paradigm of vortices commonly encountered in stirred and shaken reactors in laminar flow conditions. High resolution laser induced fluorescence and particle imaging velocimetry measurements were carried out to fully resolve the flow dissipative scales and provide a complete data set to fully assess macro- and micro-mixing characteristics. The analysis builds upon the Lamb-Oseen vortex work of Meunier and Villermaux ["How vortices mix," J. Fluid Mech. 476, 213-222 (2003)] and the engulfment model of Baldyga and Bourne ["Simplification of micromixing calculations. I. Derivation and application of new model," Chem. Eng. J. 42, 83-92 (1989); "Simplification of micromixing calculations. II. New applications," ibid. 42, 93-101 (1989)] which are valid for diffusion-free conditions, and a comparison is made between three methodologies to assess mixing characteristics. The first method is commonly used in macro-mixing studies and is based on a control area analysis by estimating the variation in time of the concentration standard deviation, while the other two are formulated to provide an insight into local segregation dynamics, by either using an iso-concentration approach or an iso-concentration gradient approach to take into account diffusion.

Stratified mixing by microorganisms