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1.
Clin Infect Dis ; 76(3): e607-e612, 2023 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-36004410

RESUMEN

BACKGROUND: Using direct-acting antivirals (DAAs) for recently acquired hepatitis C virus (RAHCV) infections, particularly in human immunodeficiency virus (HIV)-positive men who have sex with men (MSM), dramatically reduced the incidence of hepatitis C. However, implementation into clinical practice is challenging. The aim of this study was to analyze spontaneous clearance (SC) rates of RAHCV and to identify predictors of SC. METHODS: The PROBE-C study is an observational European cohort on RAHCV infections in HIV-positive MSM. Between 2007 and 2017, RAHCV infections were documented with ≥12 months of follow-up. Fisher exact, χ2, and Mann-Whitney U tests were used for statistical analysis. RESULTS: A total of 464 RAHCV infections were documented; 457 of 464 patients (98%) were male, and the median age (interquartile range [IQR]) was 41 (38-46) years. The main risk group for hepatitis C virus (HCV) transmission was MSM (98.9%). Most participants were infected with HCV genotype 1 (78.3%). The median baseline HCV RNA level (IQR) was 230 000 (135 000-474 432) IU/mL, and the median CD4+ T-cell count was 574/µL (547-604/µL. Of all cases, 92% received combination antiretroviral therapy, with 91% showing suppressed HIV RNA levels (<200 copies/mL). The median maximum alanine aminotransferase level (IQR) was 445 (402-522) U/L. SC of RAHCV infection occurred in 55 of 464 cases (11.9%). A >2-log decline in HCV RNA levels 4 weeks after diagnosis of RAHCV infection was the strongest predictor of SC (P < .001; sensitivity, 96.4%; specificity, 97.5%; positive predictive value, 84.1%; negative predictive value, 99.5%). CONCLUSIONS: SC of RAHCV in HIV-positive MSM is found in only 11.9% of cases and a <2-log drop in HCV RNA level at week 4 after diagnosis should prompt early DAA-based treatment. However, immediate DAA treatment for RAHCV infection may also be favored in patients with ongoing transmission risk behavior.


Asunto(s)
Coinfección , Infecciones por VIH , Seropositividad para VIH , Hepatitis C Crónica , Hepatitis C , Minorías Sexuales y de Género , Humanos , Masculino , Adulto , Femenino , Hepacivirus/genética , Homosexualidad Masculina , Antivirales/uso terapéutico , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Hepatitis C Crónica/tratamiento farmacológico , Hepatitis C/complicaciones , Hepatitis C/tratamiento farmacológico , Hepatitis C/epidemiología , Seropositividad para VIH/tratamiento farmacológico , VIH/genética , ARN/uso terapéutico
2.
HIV Med ; 24(4): 389-397, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36059149

RESUMEN

BACKGROUND: Since May 2022, increasing numbers of monkeypox virus (MPXV) infections have been reported from across Europe and North America. Studies, mainly from Africa, have suggested a higher risk for severe MPXV cases in people living with HIV. METHODS: This was a retrospective study of all confirmed MPXV infections observed in the participating centres since 19 May 2022. We conducted a chart review to evaluate clinical characteristics, comorbidities, and coinfections, including HIV, viral hepatitis, and sexually transmitted infections (STIs). RESULTS: By 30 June 2022, a total of 546 MPXV infections were reported from 42 German centres. All patients were men who have sex with men (MSM), of whom 256 (46.9%) were living with HIV, mostly with a preserved immune system and with viral suppression. In total, 232 (42.5%) MSM were also taking HIV pre-exposure prophylaxis (PrEP) and 58 (10.6%) MSM had no known HIV infection or PrEP use. The median age was 39 years (range 20-67), and comorbidities were rare. However, 52.4% and 29.4% of all patients had been diagnosed with at least one STI within the last 6 months or within the last 4 weeks, respectively. The most frequent localizations of MPXV infection were genital (49.9%) and anal (47.9%), whereas fever (53.2%) and lymphadenopathy (42.6%) were the most frequent general symptoms. The hospitalization rate was low (4.0%), and no fatal course was observed. The clinical picture showed no apparent differences between MSM with or without HIV. CONCLUSIONS: In this preliminary cohort analysis from a current large outbreak among MSM in Germany, the clinical picture of MPXV infection did not differ between MSM with and without HIV infection. Severe courses were rare and hospitalization rates were low. However, most patients were relatively healthy, and only a few people living with HIV were viremic or severely immunosuppressed.


Asunto(s)
Infecciones por VIH , Mpox , Profilaxis Pre-Exposición , Minorías Sexuales y de Género , Enfermedades de Transmisión Sexual , Masculino , Humanos , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Femenino , Infecciones por VIH/complicaciones , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Homosexualidad Masculina , Monkeypox virus , Estudios Retrospectivos , Enfermedades de Transmisión Sexual/epidemiología , Alemania/epidemiología
3.
Appl Opt ; 62(30): 8007-8017, 2023 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-38038095

RESUMEN

Particle self-diffusivities in unimodal and bimodal aqueous dispersions are characterized by dynamic light scattering (DLS) applying a heterodyne detection scheme. For unimodal dispersions close to infinite dilution, it could be evidenced that pure homodyne conditions cannot be realized, leading to an increasing underestimation of diffusivity with a decreasing concentration. Even for bimodal dispersions and neglecting any local oscillator field, the coherent superposition of scattered light from different particle species hinders a clear assignment of the measured signals and their evaluation for diffusivity. In this case, the impact of a cross term on the determined diffusivities cannot be neglected. The results emphasize that the use of a heterodyne detection scheme in DLS experiments is a key aspect for an accurate determination of particle diffusivities in low-concentrated unimodal and bimodal dispersions.

4.
J Chem Eng Data ; 64(9)2020.
Artículo en Inglés | MEDLINE | ID: mdl-33654329

RESUMEN

In the present study, the simultaneous and accurate determination of liquid viscosity and surface tension of the n-alkanes n-hexane (n-C6H14), n-octane (n-C8H18), n-decane (n-C10H22), and n-hexadecane (n-C16H34) by surface light scattering (SLS) in thermodynamic equilibrium is demonstrated. Measurements have been performed over a wide temperature range from 283.15 K up to 473.15 K for n-C6H14, 523.15 K for n-C8H18, and 573.15 K for n-C10H22 as well as n-C16H34. The liquid dynamic viscosity and surface tension data with average total measurement uncertainties (k = 2) of (2.0 and 1.7) % agree with the available literature and contribute to a new database at high temperatures. Over the entire temperature range, a Vogel-type equation for the dynamic viscosity and a modified van der Waals equation for the surface tension represent the measured data for the four n-alkanes within experimental uncertainties. By also considering our former SLS data for n-dodecane (n-C12H26) and n-octacosane (n-C28H58), empirical models for the liquid viscosity and surface tension of n-alkanes were developed as a function of temperature and carbon number covering values between 6 and 28. Agreement between these models and reference correlations for further selected n-alkanes which were not included in the development procedure was found.

6.
J Infect Dis ; 203(5): 595-601, 2011 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-21257738

RESUMEN

Recently, a IL28B (rs 12979860) gene polymorphism was identified as a predictor for response to hepatitis C virus-specific treatment in human immunodeficiency virus (HIV)-uninfected and -infected patients with chronic hepatitis C. In an analysis of HIV-infected patients with acute hepatitis C, we found that the IL28B genotype was associated with serum levels of hepatitis C virus RNA, g-GT, and CD4 cell count. In contrast to HIV-infected patients with chronic hepatitis C, the IL28B genotype was not significantly associated with treatment response rates in patients with acute hepatitis C. Thus, effects of the IL28B single-nucleotide polymorphism may differ in HIV-infected patients with chronic and acute hepatitis C.


Asunto(s)
Infecciones por VIH/complicaciones , Hepatitis C/genética , Hepatitis C/virología , Interleucinas/genética , Polimorfismo de Nucleótido Simple , Adulto , Anciano , Anciano de 80 o más Años , Recuento de Linfocito CD4 , Estudios de Casos y Controles , Femenino , Genotipo , Infecciones por VIH/diagnóstico , Infecciones por VIH/genética , Hepacivirus/genética , Humanos , Interferones , Masculino , Persona de Mediana Edad , ARN Viral/análisis , Análisis de Regresión , Resultado del Tratamiento
7.
Phys Chem Chem Phys ; 13(20): 9525-33, 2011 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-21487585

RESUMEN

The present study shows that dynamic light scattering (DLS) is capable of measuring mutual diffusion coefficients for binary mixtures of ionic liquids (ILs) with different molecular liquids over the complete composition range. Evidence is given that the light scattering signals are related to true molecular binary diffusion. The method stands out due to its ability to work non-invasively in macroscopic thermodynamic equilibrium with reasonable accuracy and within convenient measurement periods. Compared with other techniques, mixtures with distinctly higher viscosities can be probed. For exemplary binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO(4)]) with acetone, acetonitrile, dichloromethane, ethanol, or water as well as of 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO(3)]) with acetone, water, or methanol, mutual diffusivity data were measured over a wide range of composition at a temperature of 293.15 K. In general, the mutual diffusivity increases with increasing mole fraction of the molecular liquid and similarities to aqueous solutions of classical inorganic salts can be found. The characteristic behavior of the mutual diffusion coefficients is influenced by the nature of the chosen molecular liquid. For IL water mixtures, low light scattering intensities were observed despite the large refractive index difference of the pure components. The reason for this behavior may be the existence of water clusters in the mixtures. Additional measurements for IL acetone mixtures at temperatures ranging from 278.15 K to 323.15 K showed that the temperature dependence of the mutual diffusivity can be represented by Arrhenius functions and is increasing for decreasing mole fractions of acetone.

8.
Langmuir ; 26(8): 5971-5, 2010 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-20345184

RESUMEN

The present work provides new information on the characteristics of ion implanted metallic surfaces responsible for the adjustment of stable dropwise condensation (DWC) of steam. The results are based on condensation experiments and surface analyses via contact angle (CA) and surface free energy (SFE) measurements as well as scanning electron microscopy (SEM). For studying possible influences of the base material and the implanted ion species, commercially pure titanium grade 1, aluminum alloy Al 6951, and stainless steel AISI 321 were treated with N(+), C(+), O(+), or Ar(+) using ion beam implantation technology. The studies suggest that chemically inhomogeneous surfaces are instrumental in inducing DWC. As this inhomogeneity is apparently caused by particulate precipitates bonded to the metal surface, the resulting nanoscale surface roughness may also influence the condensation form. On such surfaces nucleation mechanisms seem to be capable of maintaining DWC even when CA and SFE measurements indicate increased wettability. The precipitates are probably formed due to the supersaturation of ion implanted metal surfaces with doping elements. For high-alloyed materials like AISI 321 or Hastelloy C-276, oxidation stimulated by the condensation process obviously tends to produce similar surfaces suitable for DWC.

9.
J Phys Chem B ; 124(12): 2482-2494, 2020 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-32105484

RESUMEN

This work contributes to an improved understanding of the fluid-phase behavior and diffusion processes in mixtures of 1-hexanol and carbon dioxide (CO2) at temperatures around the upper critical end point (UCEP) of the system. Raman spectroscopy and dynamic light scattering were used to determine the composition at saturation conditions as well as Fick and thermal diffusivities. An acceleration of the Fick diffusive process up to CO2 mole fractions of about 0.2 was found, followed by a strong slowing-down approaching vapor-liquid-liquid equilibrium or critical conditions. The acceleration of the Fick diffusive process vanished at temperatures much higher than the UCEP. Experimental Fick diffusivity data were compared with predictions from equilibrium molecular dynamics simulations and excess Gibbs energy calculations using interaction parameters from the literature. Both theoretical methods were not able to predict that the thermodynamic factor is equal to zero at the spinodal composition, stressing the need for new methodologies under such conditions. Thus, new sets of temperature-dependent interaction parameters were developed for the nonrandom two-liquid model, which improve the prediction of the Fick diffusion coefficient considerably. The link between the Fick diffusion coefficient and the nonrandomness of the liquid phases is also discussed.

10.
J Phys Chem B ; 124(20): 4146-4163, 2020 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-32315527

RESUMEN

This work contributes to the characterization of long linear and branched alkanes and alcohols via the determination of their thermophysical properties up to temperatures of 573.15 K. For this, experimental techniques including surface light scattering (SLS) and molecular dynamics (MD) simulations were used under equilibrium conditions to analyze the influences of chain length, branching, and hydroxylation on liquid density, liquid viscosity, and surface tension. For probing these effects, 12 pure model systems given by the linear alkanes n-dodecane, n-hexadecane, n-octacosane, n-triacontane, and n-tetracontane, the linear alcohols 1-dodecanol, 1-hexadecanol, and 1,12-dodecanediol, the branched alkanes 2,2,4,4,6,8,8-heptamethylnonane (HMN) and 2,6,10,15,19,23-hexamethyltetracosane (squalane), and the branched alcohols 2-butyl-1-octanol and 2-hexyl-1-decanol were investigated at or close to saturation conditions at temperatures between 298.15 and 573.15 K. Based on the experimental results for the liquid densities, liquid viscosities, and surface tensions with average expanded uncertainties (k = 2) of 0.061, 2.1, and 2.6%, respectively, the performance of the three commonly employed force fields (FFs) TraPPE, MARTINI, and L-OPLS was assessed in MD simulations. To improve the simulation results for the best-performing all-atom L-OPLS FF at larger temperatures, a modified version was suggested. This incorporates a temperature dependence for the energy parameters of the Lennard-Jones potential obtained by calibrating only against the experimental liquid density data of n-dodecane. By transferring this approach to all other systems studied, the modified L-OPLS FF shows now a distinctly better representation of the equilibrium and transport properties of the long alkanes and alcohols, especially at high temperatures.

11.
J Phys Chem B ; 123(44): 9491-9502, 2019 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-31592668

RESUMEN

Polarized dynamic light scattering (DLS) gives access to orientation-averaged translational and rotational diffusion coefficients of anisotropic particles dispersed in fluids in a single experiment. As the combination of both diffusivities contains information on the morphology of the particles, their simultaneous and accurate measurement for the same sample and thermodynamic state is beneficial for particle characterization. For nontransparent model suspensions of gold nanorods in water and water-glycerol mixtures, a scattering geometry in reflection direction was realized, which minimizes multiple scattering and allows using low laser powers to avoid laser heating. Furthermore, a heterodyne detection scheme was guaranteed by superimposing much stronger reference light to the scattered light. This ensures an unambiguous data evaluation and reduces the uncertainties for the rotational and the translational diffusivity, where the latter is accessible with smaller uncertainty. For the water-based suspensions, both diffusivities agree well with the stick hydrodynamic theory for rods and show an Andrade-type behavior in the studied temperature range from 271 to 323 K. The measured results for both diffusivities, particularly for the rotational diffusivity, indicate a breakdown of the stick boundary conditions for dynamic viscosities larger than 4 mPa·s.

12.
J Phys Chem B ; 123(41): 8777-8790, 2019 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-31536354

RESUMEN

The influence of the strength of intermolecular interactions on mass diffusive processes remains poorly understood for mixtures of associative liquids with dissolved gases. For contributing to a fundamental understanding of the interplay between liquid structures and mass diffusivities in such systems, dynamic light scattering, Raman spectroscopy, and molecular dynamics simulations were used in this work. As model systems, binary mixtures consisting of the gases hydrogen, helium, nitrogen, carbon monoxide, or carbon dioxide dissolved in ethanol, 1-hexanol, or 1-decanol were selected. Experiments and simulations were performed at macroscopic thermodynamic equilibrium close to infinite dilution of solute for temperatures between 303 and 423 K. The Fick diffusion coefficients and self-diffusivities of the gas solutes increase with increasing temperature, decreasing alkyl chain length of the 1-alcohols, and decreasing molar mass of the solutes except for helium and hydrogen showing the opposite behavior. The analysis of the liquid structure of the mixtures showed that the fraction of hydrogen-bonded alcohol molecules decreases with increasing alkyl chain length and temperature. From the obtained structure-property relationships, a new correlation was developed to predict mass diffusivities in binary mixtures consisting of n-alkanes or 1-alcohols with dissolved gases close to infinite dilution within 10% on average.

13.
J Colloid Interface Sci ; 544: 144-154, 2019 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-30831548

RESUMEN

HYPOTHESIS: The application of dynamic light scattering (DLS) is well-established for measuring diffusion coefficients related to either molecular or translational micelle diffusion. The simultaneous determination of both transport properties should be feasible, but has not been reported in the literature yet. EXPERIMENTS: Different diffusion modes present in a microemulsion and selected subsystems consisting of a polyol mixture, a binary surfactant mixture, and carbon dioxide (CO2) were investigated systematically by DLS at temperatures of (314, 333, and 353) K and corresponding pressures of (10, 13, and 16) MPa. FINDINGS: Diffusion coefficients related to molecular and translational micelle diffusion could be measured simultaneously and increase with increasing temperature. From the translational diffusion coefficients, an increase in the hydrodynamic diameter of the micelles from their non-swollen to the CO2-swollen state being in agreement with literature data for the same and similar microemulsions was found. The effective diffusion coefficients related to the faster molecular diffusion process only observable in the presence of CO2 are not affected significantly by the surfactant. The time-dependent parts of the recorded intensity correlation functions related to molecular diffusion processes are heterodyne because the scattered light modulated by molecular concentration fluctuations is superimposed with light scattered by the micelles.

14.
J Clin Med ; 8(12)2019 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-31810183

RESUMEN

BACKGROUND: Accurate assessment of hepatic fibrosis in patients with chronic HBeAg-negative Hepatitis B is of crucial importance not only to predict the long-term clinical course, but also to evaluate antiviral therapy indication. The aim of this study was to prospectively assess the utility of point shear wave elastography (pSWE) for longitudinal non-invasive fibrosis assessment in a large cohort of untreated patients with chronic HBeAg-negative hepatitis B virus (HBV) infection. METHODS: 407 consecutive patients with HBeAg-negative HBV infection who underwent pSWE, transient elastography (TE) as well as laboratory fibrosis markers, including fibrosis index based on four factors (FIB-4), aspartate to platelet ratio index (APRI) and FibroTest, on the same day were prospectively followed up for six years. Patients were classified into one of the three groups: inactive carriers (IC; HBV-DNA <2000 IU/mL and ALT <40 U/L); grey zone group 1 (GZ-1; HBV DNA <2000 IU/mL and ALT >40 U/L); grey zone group 2 (GZ-2; HBV-DNA >2000 IU/mL and ALT <40 U/L). RESULTS: pSWE results were significantly correlated with TE (r = 0.29, p < 0.001) and APRI (r = 0.17; p = 0.005). Median pSWE values did not differ between IC, GZ-1 and GZ-2 patients (p = 0.82, p = 0.17, p = 0.34). During six years of follow-up, median pSWE and TE values did not differ significantly over time (TE: p = 0.27; pSWE: p = 0.05). CONCLUSION: Our data indicate that pSWE could be useful for non-invasive fibrosis assessment and follow-up in patients with HBeAg-negative chronic HBV infection.

15.
J Clin Microbiol ; 46(1): 341-5, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17977990

RESUMEN

The sensitivity and specificity of the human immunodeficiency virus (HIV) type 1-specific immunoglobulin G capture enzyme-linked immunosorbent assay (BED-CEIA) were compared with those of the avidity index method to identify recent HIV infection using a panel of 148 samples (81 patients) representing durations of infection ranging from 0 to 222 weeks. The results from the two tests were similar (sensitivity of 80% versus 74% [P = 0.53]; specificity of 86% versus 82% [P = 0.67]).


Asunto(s)
Afinidad de Anticuerpos , Ensayo de Inmunoadsorción Enzimática/métodos , Anticuerpos Anti-VIH/sangre , Infecciones por VIH/diagnóstico , VIH-1/inmunología , Inmunoglobulina G/sangre , Adulto , Infecciones por VIH/virología , Humanos , Sensibilidad y Especificidad
16.
J Phys Chem B ; 122(12): 3163-3175, 2018 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-29485876

RESUMEN

In the present study, dynamic light scattering (DLS) experiments and molecular dynamics (MD) simulations were used for the investigation of the molecular diffusion in binary mixtures of liquids with dissolved gases at macroscopic thermodynamic equilibrium. Model systems based on the n-alkane n-hexane or n-decane with dissolved hydrogen, helium, nitrogen, or carbon monoxide were studied at temperatures between 303 and 423 K and at gas mole fractions below 0.06. With DLS, the relaxation behavior of microscopic equilibrium fluctuations in concentration and temperature is analyzed to determine simultaneously mutual and thermal diffusivity in an absolute way. The present measurements document that even for mole gas fractions of 0.007 and Lewis numbers close to 1, reliable mutual diffusivities with an average expanded uncertainty ( k = 2) of 13% can be obtained. By use of suitable molecular models for the mixture components, the self-diffusion coefficient of the gases was determined by MD simulations with an averaged expanded uncertainty ( k = 2) of 7%. The DLS experiments showed that the thermal diffusivity of the studied systems is not affected by the dissolved gas and agrees with the reference data for the pure n-alkanes. In agreement with theory, mutual diffusivities and self-diffusivities were found to be equal mostly within combined uncertainties at conditions approaching infinite dilution of the gas. Our DLS and MD results, representing the first available data for the present systems, reveal distinctly larger mass diffusivities for mixtures containing hydrogen or helium compared to mixtures containing nitrogen or carbon monoxide. On the basis of the broad range of mass diffusivities of the studied gas-liquid systems covering about 2 orders of magnitude from about 10-9 to 10-7 m2·s-1, effects of the solvent and solute properties on the temperature-dependent mass diffusivities are discussed. This contributed to the development of a simple semiempirical correlation for the mass diffusivity of the studied gases dissolved in n-alkanes of varying chain length at infinite dilution as a function of temperature. The generalized expression requiring only information on the kinematic viscosity and molar mass of the pure solvent as well as the molar mass and acentric factor of the solute represents the database from this work and further literature with an absolute average deviation of about 11%.

17.
J Phys Chem B ; 122(28): 7122-7133, 2018 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-29889520

RESUMEN

This study contributes to a fundamental understanding of how the liquid structure in a model system consisting of weakly associative n-hexane ( n-C6H14) and carbon dioxide (CO2) influences the Fickian diffusion process. For this, the benefits of light scattering experiments and molecular dynamics (MD) simulations at macroscopic thermodynamic equilibrium were combined synergistically. Our reference Fickian diffusivities measured by dynamic light scattering (DLS) revealed an unusual trend with increasing CO2 mole fractions up to about 70 mol %, which agrees with our simulation results. The molecular impacts on the Fickian diffusion were analyzed by MD simulations, where kinetic contributions related to the Maxwell-Stefan (MS) diffusivity and structural contributions quantified by the thermodynamic factor were studied separately. Both the MS diffusivity and the thermodynamic factor indicate the deceleration of Fickian diffusion compared to an ideal mixture behavior. Computed radial distribution functions as well as a significant blue-shift of the CH stretching modes of n-C6H14 identified by Raman spectroscopy show that the slowing down of the diffusion is caused by a structural organization in the binary mixtures over a broad concentration range in the form of self-associated n-C6H14 and CO2 domains. These networks start to form close to the infinite dilution limits and seem to have their largest extent at a solute-solvent transition point at about 70 mol % CO2. The current results not only improve the general understanding of mass diffusion in liquids but also serve to develop sound prediction models for Fick diffusivities.

18.
J Colloid Interface Sci ; 499: 202-208, 2017 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-28384538

RESUMEN

The applicability of dynamic light scattering (DLS) for the characterization of the size of supercritical carbon dioxide (sc-CO2)-swollen micelles in a polyester polyol-based multicomponent microemulsion with nonionic surfactant has been thoroughly proved for the first time in this work. Systematic experiments confirming that a hydrodynamic mode is observable in either a homodyne or a heterodyne detection scheme as well as the evaluation of the influence of the laser power applied to the slightly colored microemulsion have ensured an accurate implementation of this technique for a technically relevant system. The correlation times associated with the translational diffusion coefficient of the swollen micelles in a continuous liquid phase were measured for temperatures from (298.15 to 338.15)K at pressures of (90 and 100)bar. While there was no significant effect of pressure, it was found that the translational diffusion coefficient increases with increasing temperature as expected. We postulate this is primarily related to the effect of decreasing viscosity of the continuous phase. An estimation of the hydrodynamic diameter of the sc-CO2-swollen micelles is in good agreement with values for similar systems reported in the literature. For the derivation of absolute sizes for corresponding systems, also dynamic viscosity and refractive index data will be determined simultaneously in a currently developed closed experimental loop.

19.
J Phys Chem B ; 121(16): 4145-4157, 2017 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-28388084

RESUMEN

Thermophysical properties of low-viscosity ionic liquids (ILs) based on the tetracyanoborate ([B(CN)4]-) anion carrying a homologous series of 1-alkyl-3-methylimidazolium ([AMIM]+) cations [EMIM]+ (ethyl), [BMIM]+ (butyl), [HMIM]+ (hexyl), [OMIM]+ (octyl), and [DMIM]+ (decyl) were investigated by experimental methods and molecular dynamics (MD) simulations at atmospheric pressure and various temperatures. Spectroscopic methods based on nuclear magnetic resonance and surface light scattering were applied to measure the ion self-diffusion coefficients and dynamic viscosity, respectively. In terms of MD simulations, a nonpolarizable molecular model for [EMIM][B(CN)4] developed by optimization to experimental data was transferred to the other homologous ILs. For the appropriate description of the inter- and intramolecular interactions, precise and approximate force fields (FFs) were tested regarding their transferability within the homologous IL series, aiming at reducing the computational effort in molecular simulations. It is shown that at comparable simulated and experimental densities, the calculated and measured data for viscosity and self-diffusion coefficients of the ILs agree well mostly within combined uncertainties, but deviate stronger for longer-chained ILs using an overly coarse FF model. For the [B(CN)4]--based ILs studied, a comparison with literature data, the influence of varying alkyl chain length in the cation on their structural and thermophysical properties, and a correlation between self-diffusivity and viscosity are discussed.

20.
Antivir Ther ; 22(7): 619-623, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28240597

RESUMEN

BACKGROUND: No published randomized controlled data on the use of direct-acting antivirals (DAA) in acute hepatitis C (AHC) coinfection exist. However, with the AHC epidemic ongoing among men who have sex with men (MSM) these are urgently needed. METHODS: The CHAT study is a randomized controlled trial of pegylated interferon + ribavirin (PR) plus telaprevir (TVR) for 12-24 weeks versus PR alone for 24-48 weeks in the response-guided treatment of patients with AHC genotype (GT) 1 infection and HIV-1 coinfection in Germany and Great Britain. RESULTS: 34 patients were included: 15 were randomized to the PR arm (arm 1), 19 to the TVR + PR arm (arm 2). All patients were MSM, median age was 40 years. 55% had IL28B C/C GT. Median baseline HCV RNA was 291,227 IU/ml, median alanine aminotransferase was 105 U/l. 85% received cART, all had baseline HIV RNA <40 copies/ml. Overall sustained virological response (SVR12) rate was 79.4% (27/34). SVR12 was seen in 12/15 (80%) in arm 1 and in 15/19 (79.8%) in arm 2. Of the four patients without SVR in arm 2, one experienced viraI breakthrough, two were non-responders; in one case HCV protease inhibitor (PI)-associated mutations were selected under TVR (V36M, R155K). CONCLUSIONS: Due to moderate response rates and additional toxicities 1st generation HCV PIs should not be used in treating acute HCV. While not being licensed, recent study data and guidelines support the use of dual DAA therapy but optimal treatment duration in acute HCV needs further investigation.


Asunto(s)
Antivirales/uso terapéutico , Coinfección , Infecciones por VIH/virología , Hepatitis C/tratamiento farmacológico , Hepatitis C/virología , Oligopéptidos/uso terapéutico , Enfermedad Aguda , Adulto , Antivirales/administración & dosificación , Recuento de Linfocito CD4 , Quimioterapia Combinada , Femenino , Infecciones por VIH/inmunología , Humanos , Masculino , Persona de Mediana Edad , Oligopéptidos/administración & dosificación , Oligopéptidos/efectos adversos , Resultado del Tratamiento , Carga Viral
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