Estimated UV doses to psoriasis patients during climate therapy at Gran Canaria in March 2006

International audiencePsoriasis is a chronic inflammatory disease involving about 2?3% of the Norwegian population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV) radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun exposure and these biological effects is not well known. In March 2006 a study was carried out to investigate possible therapeutic outcome mechanisms in 20 psoriasis patients receiving climate therapy at Gran Canaria. This paper presents estimates of their individual skin UV-doses based on UV measurements and the patients' diaries with information on time spent in the sun. On the first day of exposure the patients received on average 5.1 Standard Erythema Doses (SED: median=4.0 SED, range 2.6?10.3 SED) estimated to the skin. During the 15 days study they received 165.8 SED (range 104.3?210.1 SED). The reduction in PASI score was 72.8% on average, but there was no obvious relation between the improvement and the UV dose. The UV doses were higher than those found from climate therapy studies at other locations. It seems beneficial to use more strict exposure schedules that consider the available UV irradiance, depending on time of the day, time of the year and weather conditions

The "zeroth law" of turbulence: Isotropic turbulence simulations revisited

The dimensionless kinetic energy dissipation rate C_epsilon is estimated from numerical simulations of statistically stationary isotropic box turbulence that is slightly compressible. The Taylor microscale Reynolds number Re_lambda range is 20 < Re_lambda < 220 and the statistical stationarity is achieved with a random phase forcing method. The strong Re_lambda dependence of C_epsilon abates when Re_lambda approx. 100 after which C_epsilon slowly approaches approx 0.5 a value slightly different to previously reported simulations but in good agreement with experimental results. If C_epsilon is estimated at a specific time step from the time series of the quantities involved it is necessary to account for the time lag between energy injection and energy dissipation. Also, the resulting value can differ from the ensemble averaged value by up to +-30%. This may explain the spread in results from previously published estimates of C_epsilon.Comment: 7 pages, 7 figures. Submitted to Phys. Rev.

Probability density function of turbulent velocity fluctuations in rough-wall boundary layer

The probability density function of single-point velocity fluctuations in turbulence is studied systematically using Fourier coefficients in the energy-containing range. In ideal turbulence where energy-containing motions are random and independent, the Fourier coefficients tend to Gaussian and independent of each other. Velocity fluctuations accordingly tend to Gaussian. However, if energy-containing motions are intermittent or contaminated with bounded-amplitude motions such as wavy wakes, the Fourier coefficients tend to non-Gaussian and dependent of each other. Velocity fluctuations accordingly tend to non-Gaussian. These situations are found in our experiment of a rough-wall boundary layer.Comment: 6 pages, to appear in Physical Review

False-negative malaria rapid diagnostic tests in Rwanda: impact of Plasmodium falciparum isolates lacking hrp2 and declining malaria transmission

Rapid diagnostic tests (RDTs) for histidine rich protein 2 (HRP2) are often used to determine whether persons with fever should be treated with anti-malarials. However, Plasmodium falciparum parasites with a deletion of the hrp2 gene yield false-negative RDTs and there are concerns the sensitivity of HRP2-based RDTs may fall when the intensity of transmission decreases.; This observational study enrolled 9226 patients at three health centres in Rwanda from April 2014 to April 2015. It then compared the sensitivity of RDTs based on HRP2 and the Plasmodium lactate dehydrogenase (pLDH) to microscopy (thick smears) for the diagnosis of malaria. PCR was used to determine whether deletions of the histidine-rich central repeat region of the hrp2 gene (exon 2) were associated with false-negative HRP2-based RDTs.; In comparison to microscopy, the sensitivity and specificity of HRP2- and pLDH-based RDTs were 89.5 and 86.2% and 80.2 and 94.3%, respectively. When the results for both RDTs were combined, sensitivity rose to 91.8% and specificity was 85.7%. Additionally, when smear positivity fell from 46 to 3%, the sensitivity of the HRP2-based RDT fell from 88 to 67%. Of 370 samples with false-negative HRP2 RDT results for which PCR was performed, 140 (38%) were identified as P. falciparum by PCR. Of the isolates identified as P. falciparum by PCR, 32 (23%) were negative for the hrp2 gene based on PCR. Of the 32 P. falciparum isolates negative for hrp2 by PCR, 17 (53%) were positive based on the pLDH RDT.; This prospective study of RDT performance coincided with a decline in the intensity of malaria transmission in Kibirizi (fall in slide positivity from 46 to 3%). This decline was associated with a decrease in HRP2 RDT sensitivity (from 88 to 67%). While P. falciparum isolates without the hrp2 gene were an important cause of false-negative HRP2-based RDTs, most were identified by the pLDH-based RDT. Although WHO does not recommend the use of combined HRP2/pLDH testing in sub-Saharan Africa, these results suggest that combination HRP2/pLDH-based RDTs could reduce the impact of false-negative HRP2-based RDTs for detection of symptomatic P. falciparum malaria

Microstructure and phase stability of suspension high velocity oxy-fuel sprayed yttria stabilised zirconia coatings from aqueous and ethanol based suspensions

Two commercial 7-8 wt.% Yttria Stabilised Zirconia (YSZ) suspensions were sprayed by Suspension High Velocity Oxy Fuel (SHVOF) thermal spraying for advanced high temperature coatings. Heat treatments of the free-standing coatings were conducted at 800 °C and 1000 °C for 72 h. The SHVOF coatings using two liquid carriers: water and ethanol, behaved differently in terms of micro-structure and phase stability. The ethanol coatings retained a fully tetragonal composition after heat treatments; while the aqueous coatings, however, underwent the undesirable tetragonal to monoclinic phase transformation at 1000 °C, which is lower than previously reported temperatures (>1200 °C) in thermal sprayed YSZ coatings. The heat treatments not only resulted in densification of both coatings, but also caused excessive crystallite growth in aqueous coatings promoting the undesirable phase transformation. On the contrary, the ethanol suspension improved the phase stability by favouring the homogenization of yttrium during spraying

The SPAIR method: Isolating incident and reflected directional wave spectra in multidirectional wave basins

Wave tank tests aiming to reproduce realistic or site specific conditions will commonly involve using directionally spread, short-crested sea states. The measurement of these directional characteristics is required for the purposes of calibrating and validating the modelled sea state. Commonly used methods of directional spectrumreconstruction, based on directional spreading functions, have an inherent level of uncertainty associated with them. In this paper we aim to reduce the uncertainty in directional spectrum validation by introducing the SPAIR (Single-summation PTPD Approach with In-line Reflections) method, in combination with a directional wave gauge array. A variety of wave conditions were generated in the FloWave Ocean Energy Research Facility, Edinburgh, UK, to obtain a range of sea state and reflection scenarios. The presented approach is found to provide improved estimates of directional spectra over standardmethods, reducing the mean apparent directional deviation down to below 6% over the range of sea states. Additionally, the method isolates incident and reflected spectra in both the frequency and time domain, and can separate these wave systems over 360°. The accuracy of themethod is shown to be only slightly sensitive to the level of in-line reflectionpresent,but at present cannot dealwithoblique reflections. The SPAIRmethod, as presented or with slightmodification, will allow complex directional sea states to be validated more effectively, enabling multidirectional wave basins to simulate realistic wave scenarios with increased confidence

Renormalization group in the infinite-dimensional turbulence: third-order results

The field theoretic renormalization group is applied to the stochastic Navier-Stokes equation with the stirring force correlator of the form k^(4-d-2\epsilon) in the d-dimensional space, in connection with the problem of construction of the 1/d expansion for the fully developed fluid turbulence beyond the scope of the standard epsilon expansion. It is shown that in the large-d limit the number of the Feynman diagrams for the Green function (linear response function) decreases drastically, and the technique of their analytical calculation is developed. The main ingredients of the renormalization group approach -- the renormalization constant, beta function and the ultraviolet correction exponent omega, are calculated to order epsilon^3 (three-loop approximation). The two-point velocity-velocity correlation function, the Kolmogorov constant C_K in the spectrum of turbulent energy and the inertial-range skewness factor S are calculated in the large-d limit to third order of the epsilon expansion. Surprisingly enough, our results for C_K are in a reasonable agreement with the existing experimental estimates.Comment: 30 pages with EPS figure

Evaluation of Phase Feeding and Complete Diet Blending at Different Standardized Ileal Digestible Lysine Levels on Growing-Finishing Pigs’ Growth Performance, Carcass Characteristics, and Diet Economics

A total of 2,160 mixed-gender pigs (PIC 337 × 1050; initially 54.8 ± 9.4 lb) were used in the 120-d study to compare feeding strategies (phase feeding vs. complete diet blending) at different SID Lys levels (90 vs. 100% of requirement estimates) on finishing pig growth performance, carcass characteristics, and economics. Pens of pigs were randomly assigned to 1 of 4 treatments following a completely randomized block design with barn and initial body weight as blocking factors. The treatments included two feeding programs, a 5-phase feeding strategy at either 90% (Phase-90) or 100% of SID Lys requirement estimates (Phase-100); or two programs with complete diet blending, with pre-defined mixing proportions of a low and high SID Lys diet to meet 90 (Blend-90) or 100% (Blend-100) of the SID Lys curve requirement estimates for 50- to 280-lb pigs. Pigs in the phase-feeding strategies were fed on a feed budget with 47, 144, 147, 138, and 136 lb of feed per pig for phases 1 to 5, respectively. Body weights at any period of the trial and overall ADG (d 0 to 120) were not affected by the feeding strategy nor by diet SID Lys levels. In contrast, the overall ADFI of pigs fed by diet blending was lower than the ADFI of those fed by phase feeding (P = 0.002), resulting in improved F/G (P \u3c 0.001). The SID Lys levels did not influence overall ADFI or F/G. Hot carcass weight, carcass yield, lean percentage, fat depth, and loin depth were not affected by the feeding program. Despite the lower overall ADFI of pigs fed by diet blending, the feeding strategy resulted in no significant differences in economic criteria except for feed cost per lb of gain at the high price scenario (P = 0.049). With low diet cost, the 90% SID Lys level resulted in lower feed cost per pig and feed cost per lb of gain than 100% SID Lys, but this was not reflected in income over feed cost (IOFC). In conclusion, diet blending at either 90 or 100% of the SID Lys requirement estimate improved F/G by reducing ADFI without impacting ADG or carcass characteristics. At current prices used in this study, feeding strategies at either 90 or 100% SID Lys did not significantly affect IOFC, but feeding 90% of the SID Lys recommendation reduced the feed cost

Doppler spectra of airborne sound backscattered by the free surface of a shallow turbulent water flow

Measurements of the Doppler spectra of airborne ultrasound backscattered by the rough dynamic surface of a shallow turbulent flow are presented in this paper. The interpretation of the observed acoustic signal behavior is provided by means of a Monte Carlo simulation based on the Kirchhoff approximation and on a linear random-phase model of the water surface elevation. Results suggest that the main scattering mechanism is from capillary waves with small amplitude. Waves that travel at the same velocity of the flow, as well as dispersive waves that travel at a range of velocities, are detected, studied and used in the acoustic Doppler analysis. The dispersive surface waves are not observed when the flow velocity is slow compared to their characteristic velocity. Relatively wide peaks in the experimental spectra also suggest the existence of nonlinear modulations of the short capillary waves, or their propagation in a wide range of directions. The variability of the Doppler spectra with the conditions of the flow can affect the accuracy of the flow velocity estimations based on backscattering Doppler. A set of different methods to estimate this velocity accurately and remotely at different ranges of flow conditions is suggested