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Abstract: The contribution of regional, urban and traffic sources to PM2.5 and PM10 in an urban area was investigated in this study. The chemical composition of PM2.5 and PM10 was measured over a year at a street location and up- and down-wind of the city of Rotterdam, the Netherlands. The 14C content in EC and OC concentrations was also determined, to distinguish the contribution from “modern” carbon (e.g., biogenic emissions, biomass burning and wildfires) and fossil fuel combustion. It was concluded that the urban background of PM2.5 and PM10 is dominated by the regional background, and that primary and secondary PM emission by urban sources contribute less than 15%. The 14C analysis revealed that 70% of OC originates from modern carbon and 30% from fossil fuel combustion. The corresponding percentages for EC are, respectively 17% and 83%. It is concluded that in particular the urban population living in street canyons with intense road traffic has potential health risks. This is due to exposure to elevated concentrations of a factor two for EC from exhaust emissions in PM2.5 and a factor 2–3 for heavy metals from brake and tyre wear, and re-suspended road dust in PM10. It follows that local air quality management may focus on local measures to street canyons with intense road traffic. [Copyright &y& Elsevier]

Three-dimensional plotting of micro-extruded filaments is a promising method for the manufacture of porous structures in thermoplastic polymers. However, it has been noted that conventional dispense head systems for this microextrusion are unsuitable for the reliable processing of thermally sensitive polymers like poly(lactic acid) (PLA): the batch polymer remains in the molten state prior to processing and it will degrade under this thermal load, leading to polymer chain reduction. Therefore, a new dispense head system was developed which thermally separates a cold material supply zone from the hot extrusion zone and allows for the processing of PLA-based polymers without severe degradation. This manuscript discusses the design of the new dispense head and compares its thermoregulation with that of a conventional system by means of finite element modeling and infrared imaging. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

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In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RH<30-40%). Since ambient aerosol particles experience hygroscopic growth at enhanced RH, also their microphysical and optical properties - especially the aerosol light scattering - are strongly dependent on RH. The knowledge of this RH effect is of crucial importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. Here, we will present results from a four-month campaign which took place in summer 2009 in Cabauw, The Netherlands. The aerosol scattering coefficient σsp(λ) was measured dry and at various, predefined RH conditions between 20 and 95% with a humidified nephelometer. The scattering enhancement factor f(RH, λ) is the key parameter to describe the effect of RH on σsp(λ) and is defined as σsp(RH, λ)measured at a certain RH divided by the dry σsp(dry, λ). The measurement of f(RH, λ) together with the dry absorption measurement (assumed not to change with RH) allows the determination of the actual extinction coefficient σep(RH, λ) at ambient RH. In addition, a wide range of other aerosol properties were measured in parallel. The measurements were used to characterize the effects of RH on the aerosol optical properties. A closure study showed the consistency of the aerosol in-situ measurements. Due to the large variability of air mass origin (and thus aerosol composition) a simple parameterization of f(RH,λ) could not be established. If f(RH,λ) needs to be predicted, the chemical composition and size distribution needs to be known. Measurements of four MAX-DOAS (multi-axis differential optical absorption spectroscopy) instruments were used to retrieve vertical profiles of σep(λ). The values of the lowest layer were compared to the in-situ values after conversion of the latter to ambient RH. The comparison showed a good correlation of R² = 0.62-0.78, but the extinction coefficients were a factor of 1.5-3.4 larger than the in-situ values. Best agreement is achieved for a few cases characterized by low aerosol optical depths and low planetary boundary layer heights. Differences showed to be dependent on the applied MAX-DOAS retrieval algorithm. The comparison of the in-situ data to a Raman lidar (light detection and ranging) showed a good correlation and higher values measured by the lidar (R² = 0.79, slope of 1.81) if the Raman retrieved profile was used to extrapolate the directly measured extinction coefficient to the ground. The comparison improved if only nighttime measurements were used in the comparison (R² = 0.93, slope of 1.19). [ABSTRACT FROM AUTHOR]

The article presents a study on several correction algorithms of the Aethalometer (AE) absorption coefficients including Weingartner, Arnott, and Schmid. It notes that all corrections were tested, evaluated, and analyzed on six datasets which represent different aerosol types. The study poses several recommendations including the storage of measured attenuation values in databases, the modification of the absorption coefficient wavelength dependence, and the use of the filter-loading correction.

Primary marine aerosol fluxes were measured using eddy covariance (EC), a condensation particle counter (CPC) and an optical particle counter (OPC) with a heated inlet. The later was used to discriminate between sea salt and total aerosol. Measurements were made from the 25m tower at the research station Mace Head at the Irish west coast, May to September 2002. The aerosol fluxes were dominated by upward fluxes, sea spray from bubble bursting at the ocean surface. The sea salt aerosol number emissions increased two orders of magnitude with declining diameter from 1 to 0.1 µm where it peaked at values of 105 to 107 particles m-2s-1. The sea salt emissions increased at all sizes in the wind range 4 to 22 ms-1, in consistency with a power function of the wind speed. The sea salt emission data were compared to three recent sub micrometer sea salt source parameterisations. The best agreement was with Måartensson et al. (2003), which appear to apply from 0.1 to 1.1 µm diameters in temperate water (12°C) as well as tropical water (25°C). The total aerosol emissions were independent of the wind speed below 10 ms-1, but increased with the wind above 10 ms-1. The aerosol volume emissions were larger for the total aerosol than for the sea salt at all wind speeds, while the sea salt number emissions approached the total number emissions at 15 ms-1. It is speculated that this is caused by organic carbon in the surface water that is depleted at high wind speeds. The data are consistent with an internal aerosol mixture of sea salt, organic carbon and water. Using the aerosol model by Ellison et al. (1999) (a mono-layer of organic carbon surrounding a water-sea-salt brine) we show that the total and sea salt aerosol emissions are consistent. This predict that the organic carbon fraction increase with decreasing diameter from a few % at 1 µm over 50% at about 0.5 µm to about 90% at 0.1 µm, in consistency with simultaneous chemical data by Cavalli et al. (2004). The combined models of Mårtensson et al. (2003) and Ellison et al. (1999) reproduce the observed total aerosol emissions and offer an approach to model the organic sea spray fraction. [ABSTRACT FROM AUTHOR]

Transsexualism implies that an anatomically normal individual feels that he or she is actually a member of the opposite sex. Treatment usually includes real-life experience along with hormone therapy and sex reassignment surgery. Voice modification surgery may be necessary, as pass ability in general is still in a large extent dependent on the aspects of voice in transsexual people. Often male-to-female patients report being addressed in telephone conversations as their genetic gender, which is experienced as a disability. The purpose of this study was to evaluate the impact of voice on the quality of life in transsexuals.In order to detect the disability caused by a voice disorder, the validated assessment method the Voice Handicap Inventory (VHI) was used. An additional question about the way patients were addressed in a telephone conversation was added.As part of a study describing general health in transsexual persons, done at the Ghent University Hospital Belgium, a total of 48 patients were evaluated. In female-to-male transsexuals the median scores were very low, suggesting testosterone treatment led to an acceptable voice alteration. A higher serum LH level was significantly correlated with higher total, functional and emotional VHI scores. In male-to-female transsexuals the scores were significantly higher than those of the female-to-male transsexuals, but still there was no indication of a real disability/handicap. The extra telephone question was scored higher suggesting male-to-female transsexuals did experience a disability caused by their voice. From this study it is concluded that the VHI values did not demonstrate a handicapping effect. [ABSTRACT FROM AUTHOR]

We report a schwannoma with a rare location at the tip of the nose in a 20-year-old woman with an otherwise unremarkable medical history. The imaging findings unterline the usefulness of MRI in narrowing down the differential diagnosis of masses in this region. Once the diagnosis was focussed on a neural origin of the mass, the exact nature of the tumour could not be predicted from the MRI, although the presence of a capsule on imaging studies as well as at operation suggested it was probably a schwannoma. A schwannoma must be considered when one encounters a sharply delineated mass at the tip of the nose, showing high signal on T2-weighted images and strongly contrast enhancement. [ABSTRACT FROM AUTHOR]