Randomized controlled trial of an intervention to prevent adherence failure among HIV-infected patients initiating antiretroviral therapy.

Objective: Compare the efficacy of a multicomponent social support intervention to standard-of-care counseling on medication adherence among HIV-infected patients initiating antiretroviral therapy. Design: Randomized controlled trial. Generalized estimating equations tested for differences in the percentage of participants achieving 90% adherence. Main Outcome Measures: Pill-taking, electronically monitored over 6 consecutive months; plasma viral load (VL), assessed at 3 and 6 months following initiation of therapy. Results: Of 226 participants who were randomized and began the trial, 87 (38%) were lost to the study by 6 months. The proportion of adherent participants declined steadily over time, with no time by group interaction. Sustained adherence was associated with increased odds of achieving an undetectable VL (OR = 1.78; 95% CI = 1.01, 3.13). In intention-to-treat analyses, a larger proportion of the intervention group than the control group was adherent (40.15% vs. 27.59%, p = .02) and achieved an undetectable VL p = .04). However, the majority of participants who remained on study experienced some reduction in VL (≥ 1-log drop or undetectable), regardless of experimental condition. Conclusion: The multicomponent social support intervention significantly improved medication adherence over standard-of-care counseling; evidence for improved virologic outcomes was inconsistent. Early discontinuation of care and treatment may be a greater threat to the health of HIV patients than imperfect medication-taking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical and computational scaling issues in lattice Boltzmann simulations of binary fluid mixtures

We describe some scaling issues that arise when using lattice Boltzmann (LB) methods to simulate binary fluid mixtures--both in the presence and absence of colloidal particles. Two types of scaling problem arise: physical and computational. Physical scaling concerns how to relate simulation parameters to those of the real world. To do this effectively requires careful physics, because (in common with other methods) LB cannot fully resolve the hierarchy of length, energy and time-scales that arise in typical flows of complex fluids. Care is needed in deciding what physics to resolve and what to leave unresolved, particularly when colloidal particles are present in one or both of two fluid phases. This influences steering of simulation parameters such as fluid viscosity and interfacial tension. When the physics is anisotropic (for example, in systems under shear) careful adaptation of the geometry of the simulation box may be needed; an example of this, relating to our study of the effect of colloidal particles on the Rayleigh-Plateau instability of a fluid cylinder, is described. The second and closely related set of scaling issues are computational in nature: how do you scale-up simulations to very large lattice sizes? The problem is acute for systems undergoing shear flow. Here one requires a set of blockwise co-moving frames to the fluid, each connected to the next by a Lees-Edwards like boundary condition. These matching planes lead to small numerical errors whose cumulative effects can become severe; strategies for minimizing such effects are discussed.     

Effect of Geometric Discontinuities on Strains in FRP-Wrapped Columns

Extensive research on fiber-reinforced polymer (FRP) confinement strengthening for concrete columns has led to a good understanding of, and accurate models for, circular columns subjected to axial load. This research is being extended to noncircular and eccentrically loaded columns, steel tubular, and concrete-filled steel tubular columns. A significant gap in our understanding of all these columns, however, is that the apparent FRP strain at failure is significantly lower than the ultimate strain in a flat coupon test. There may be many factors contributing to this complex phenomenon. This paper shows that one of these factors is the geometrical discontinuities at the ends of the FRP wrap. The significance of the effect of discontinuities on the strain concentrations in the FRP wrap and the bonding adhesive is explored through an elastic finite-element analysis.     

Domain growth in cholesteric blue phases: Hybrid lattice Boltzmann simulations

Here we review a hybrid lattice Boltzmann algorithm to solve the equations of motion of cholesteric liquid crystals. The method consists in coupling a lattice Boltzmann solver for the Navier–Stokes equation to a finite difference method to solve the dynamical equations governing the evolution of the liquid crystalline order parameter. We apply this method to study the growth of cholesteric blue phase domains, within a cholesteric phase. We focus on the growth of blue phase II and on a thin slab geometry in which the domain wall is flat. Our results show that, depending on the chirality, the growing blue phase is either BPII with no or few defects, or another structure with hexagonal ordering. We hope that our simulations will spur further experimental investigations on quenches in micron-size blue phase samples. The computational size that our hybrid lattice Boltzmann scheme can handle suggests that large scale simulations of new generation of blue phase liquid crystal devices are within reach.     

Reactive Compensation and Harmonic Suppression for Industrial Power Systems Using Thyristor Converters

This paper discusses the problems and solutions of applying reactive compensation, either static or dynamic, to industrial power systems supplying large blocks of dc power from diode or thyristor converters. The resonance between power capacitors and system reactance can produce high harmonic voltages caused by the harmonic currents generated by converters. The interaction between these harmonic voltages and regulating systems can be minimized by the use of suitable filters. The design of these filters should eliminate the interaction between power system and load and reduce harmonic current flow. Different methods of reactive power control are also discussed.     

A randomized controlled trial of transcutaneous electrical nerve stimulation (CODETRON) to determine its benefits in a rehabilitation program for acute occupational low back pain

The authors report the results of a randomized controlled trial to examine the effectiveness of transcutaneous electrical nerve stimulation (TENS/CODETRON) when added to a standard exercise program for industrial workers with acute low back pain (LBP). Fifty-eight work-injured patients with LBP of 3-10 weeks duration were randomized into two groups that received actual or placebo stimulation in combination with the exercise regimen. The groups were compared on the primary outcome measures of disability, pain, and return to work. No significant differences between the experimental and placebo groups were discovered on any of the measured outcomes. Exercise alone, when continued over 4 weeks, reduced disability and pain scores significantly. Under the experimental conditions of this trial, no additional benefits of TENS/CODETRON were detected when added to an active exercise regimen.     

Application Considerations in Handling Effects of SCR Generated Harmonics in Cement Plants

Loads that inject harmonics into power distribution systems have existed for many years. Such harmonics produced by discontinuous conducting devices and nonlinear loads created few recognized problems for most cement plant power distribution systems installed prior to 1960 because of the small amount of harmonic generating loads present on such systems. With the advent of large thyristor-controlled equipment, considerable attention has been directed to harmonic currents required by such loads and the resultant harmonic voltages produced by the passage of such currents through the power system.     

Internal loading of phosphorus in a sedimentation pond of a treatment wetland: effect of a phytoplankton crash

Sedimentation ponds are widely believed to act as a primary removal process for phosphorus (P) in nutrient treatment wetlands. High frequency in-situ P, ammonium (NH₄⁺) and dissolved oxygen measurements, alongside occasional water quality measurements, assessed changes in nutrient concentrations and productivity in the sedimentation pond of a treatment wetland between March and June. Diffusive equilibrium in thin films (DET) probes were used to measure in-situ nutrient and chemistry pore-water profiles. Diffusive fluxes across the sediment-water interface were calculated from the pore-water profiles, and dissolved oxygen was used to calculate rates of primary productivity and respiration. The sedimentation pond was a net sink for total P (TP), soluble reactive P (SRP) and NH₄⁺ in March, but became subject to a net internal loading of TP, SRP and NH₄⁺ in May, with SRP concentrations increasing by up to 41 μM (1300 μl^− 1). Reductions in chlorophyll a and dissolved oxygen concentrations also occurred at this time. The sediment changed from a small net sink of SRP in March (average diffusive flux: − 8.2 μmol m^− 2 day^− 1) to a net source of SRP in June (average diffusive flux: + 1324 μmol m^− 2 day^− 1). A diurnal pattern in water column P concentrations, with maxima in the early hours of the morning, and minima in the afternoon, occurred during May. The diurnal pattern and release of SRP from the sediment were attributed to microbial degradation of diatom biomass, causing reduction of the dissolved oxygen concentration and leading to redox-dependent release of P from the sediment. In June, 2.7 mol-P day^− 1 were removed by photosynthesis and 23 mol-P day^− 1 were supplied by respiration in the lake volume. SRP was also released through microbial respiration within the water column, including the decomposition of algal matter. It is imperative that consideration to internal recycling is given when maintaining sedimentation ponds, and before the installation of new ponds designed to treat nutrient waste.     

The potential application of vanillin in preventing yeast spoilage of soft drinks and fruit juices

The preservative effect of vanillin, the major constituent of vanilla beans, was studied in an apple juice and peach-flavored soft drink. Vanillin activity was tested against Saccharomyces cerevisiae and Candida parapsilosis at 8 and 25 degrees C over an 8-week storage period. Initial results in laboratory media indicated minimum inhibitory concentration values of 17 and 9 mM vanillin for the two yeast strains. Concentrations of 20 and 10 mM vanillin, respectively, were required to achieve complete inhibition of both yeast strains inoculated at a level of approximately 10(4) CFU/ml in the apple juice and peach-flavored soft drink over the 8-week storage at 25 degrees C. These effective levels were reduced to 5 and 1 mM, when the storage temperature was reduced to 8 degrees C. A biocidal effect against both yeasts was observed within 96 h to 8 weeks, with vanillin concentrations of 5 to 40 mM depending on the beverage and the storage temperatures used. The increased activity of vanillin in the peach-flavored soft drink (pH 3.1) in comparison to the apple juice (pH 3.5) is probably a result of the lower intrinsic pH of the former; however, variation in vitamin and mineral levels or the presence of other phenolic compounds between the two drinks might also have contributed to the observed differences. Furthermore, the increased activity at the lower temperature could be linked to the combination of the increased membrane fluidity and the membrane-perturbing action of vanillin. We conclude that vanillin has the potential to preserve fruit juices and soft drinks that are low in both lipid and protein content against S. cerevisiae and C. parapsilosis.     

Physiological characterization of spoilage strains of Zygosaccharomyces bailii and Zygosaccharomyces rouxii isolated from high sugar environments

Two isolates of spoilage yeasts Zygosaccharomyces bailii and Zygosaccharomyces rouxii were obtained from a high sugar environment, in a factory producing candied fruit and nougat. Other strains, Z. bailii from other environments and other isolates from high sugar/salt environments were obtained for comparison (Zygosaccharomyces lentus, Candida magnoliae, Candida halophila and Pichia guilliermondii). A full physiological assessment of these isolates was carried out, of preservative and biocide resistance, osmotolerance, ethanol-tolerance, low pH resistance, degree of fermentation, and growth temperature and survival to pasteurisation. Results showed that the strains isolated from high sugar environments did not show extreme physiology. These were robust strains but within the normal parameters expected for the species. One exception to this was that the Z. bailii strains were abnormally able to grow at 37 degrees C. In all strains other than C. magnolia and C. halophila, cells were able to adapt to high levels of sugar. Cultures grown in high glucose concentrations were subsequently able to tolerate higher concentrations of glucose than previously. Similarly, high sugar was found to confer a degree of protection against pasteurisation, enabling survival in what would have otherwise been a lethal treatment. Isolates of Z. bailii showed a high level of resistance to preservatives such as sorbic acid, benzoic acid, acetic acid, cinnamic acid, and ethanol, and also to heat. Unexpectedly Z. bailii isolates were not exceptionally resistant to biocides such as peracetic acid, or hypochlorite. These results indicate that spoilage by yeasts such as Z. bailii may be better prevented by use of biocidal cleaning agents in the factory, rather than treating the food with preservatives.