Search results for " Size"
showing 10 items of 2281 documents
Targeted Hybrid Nanocarriers as a System Enhancing the Skin Structure
2021
The skin is constantly exposed to external and internal factors that disturb its function. In this work, two nanosystems-levan nanoparticles and a surfactin-stabilized nanoemulsion were preserved (tested for microbial growth) and characterized (size, polydispersity, Zeta potential, and stability). The nanosystems were introduced in the model formulations-cream, tonic, and gel, and confirmed by TEM. The analysis showed that nanoemulsion has a spherical morphology and size 220–300 nm, while levan nanoparticles had irregular shapes independently of the use of matrix and with particle size (130–260 nm). Additionally, we examined the antiradical effect of levan nanoparticles and nanoemulsion in …
Design Issues and Sample Size when Exposure Measurement is Inaccurate
2001
AbstractMeasurement error often leads to biased estimates and incorrect tests in epidemiological studies. These problems can be corrected by design modifications which allow for refined statistical models, or in some situations by adjusted sample sizes to compensate a power reduction. The design options are mainly an additional replication or internal validation study. Sample size calculations for these designs are more complex, since usually there is no unique design solution to obtain a prespecified power. Thus, additionally to a power requirement, an optimal design should also fulfill the criteria of minimizing overall costs. In this review corresponding strategies and formulae are descr…
Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula
2012
The Eyjafjallajökull ash that crossed over Spain and Portugal on 6e12 May 2010 has been monitored by a set of operational sun photometer sites within AERONET-RIMA and satellite sensors. The sun photometer observations (aerosol optical depth, coarse mode concentrations) and ash products from IASI and SEVIRI satellite sensors, together with FLEXPART simulations of particle transport, allow identifying the volcanic aerosols. The aerosol columnar properties derived from inversions were investigated, indicating specific properties, especially regarding the absorption. The single scattering albedo was high (0.95 at 440 nm) and nearly wavelength independent, although with slight decrease with wave…
Force control and powder dispersibility of spray dried particles for inhalation
2009
This study aims towards a deeper understanding of the correlation between particle morphology, cohesion forces, and aerosol performance of spray dried powders for inhalation. Therefore, forces affecting cohesion and dispersion are consid- ered and some novel contact models are introduced to explain the improved powder dispersibility of corrugated particles. Particles with different degrees of corrugation are prepared by spray drying and characterized. Powder dispersibility is measured by positioning a dry powder inhaler in front of the laser diffraction device. The particle sizes of all powders are in the range of x50 ¼ 2.11 � 0.15 mm. The ratio of mass specific surface area Sm to volume sp…
Effective broadband refractive index retrieval by a white light optical particle counter.
2009
A new approach to retrieve the effective broadband refractive indices (nbroad,eff) of aerosol particles by a white light aerosol spectrometer (WELAS) optical particle counter (OPC) is presented. Using a tandem differential mobility analyzer (DMA)-OPC system, the nbroad,eff are obtained for both laboratory and field applications. This method was tested in the laboratory using substances with a wide range of optical properties. With the obtained nbroad,eff, WELAS aerosol size distributions can be corrected. Therefore, this method can be used for instrument calibration in both laboratory and field measurements. The retrieved effective broadband refractive indices for the scattering aerosols we…
Affective temperaments in tango dancers.
2015
Background: Links between affective temperaments and folk culture have been infrequently explored systematically. Creativity and personality and temperament studies, conversely, have reported several associations. Tango is one of the most typical Argentinean folk dance-musical repertoires. The main purpose of this study is to compare affective temperaments between Argentinean professional tango dancers and the general population. Methods: TEMPS-A was administered to a sample of 63 professional tango dancers and 63 comparison subjects from the general population who did not practice tango. Subscale median scores and total median scores with non-parametric statistics were analyzed. Results: M…
Age-dependent inbreeding risk and offspring fitness costs in female black grouse
2011
Dispersal is an important mechanism used to avoid inbreeding. However, dispersal may only be effective for part of an individual's lifespan since, post-dispersal individuals that breed over multiple reproductive events may risk mating with kin of the philopatric sex as they age. We tested this hypothesis in black grouse Tetrao tetrix , and show that yearling females never mated with close relatives whereas older females did. However, matings were not with direct kin suggesting that short-distance dispersal to sites containing kin and subsequent overlap of reproductive lifespans between males and females were causing this pattern. Chick mass was lower when kinship was high, suggesting impor…
Mitochondria, oxidative stress and aging
2000
In the eighties, Miquel and Fleming suggested that mitochondria play a key role in cellular aging. Mitochondria, and specially mitochondrial DNA (mtDNA), are major targets of free radical attack. At present, it is well established that mitochondrial deficits accumulate upon aging due to oxidative damage. Thus, oxidative lesions to mtDNA accumulate with age in human and rodent tissues. Furthermore, levels of oxidative damage to mtDNA are several times higher than those of nuclear DNA. Mitochondrial size increases whereas mitochondrial membrane potential decreases with age in brain and liver. Recently, we have shown that treatment with certain antioxidants, such as sulphur-containing antioxid…
Terminal nerve in the mouse-eared bat (Myotis myotis): ontogenetic aspects.
2006
As in other mammals, ontogenesis of the terminal nerve (TN) in the mouse-eared bat (Myotis myotis) starts shortly after the formation of the olfactory placode, a derivative of the ectoderm. During development of the olfactory pit, proliferating neuroblasts thicken the placodal epithelium and one cell population migrates toward the rostroventral tip of the telencephalon. Here they accumulate in a primordial terminal ganglion, which successively divides into smaller units. Initial fibers of the TN can be distinguished from olfactory fibers in the mid-embryonic period. The main TN fiber bundle (mfb) originates from the anteriormost ganglion in the nasal roof, whereas one or more inconstant sma…
Role of Crassicauda sp. in natural mortality of pantropical spotted dolphins Stenella attenuata: a reassesment
2014
Evaluating the effect of parasites on population size is essential for designing management and conservation plans of wild animal populations. Although knowledge in this area is scarce in cetaceans, current evidence suggests that species of the nematode genus Crassicauda may play an important regulatory role in some populations. In the present study, a semiparametric regression technique is applied to a previously published dataset to re-examine the role of Crassicauda sp. in natural mortality of pantropical spotted dolphins Stenella attenuata. The resulting model indicated parasite-induced mortality at ages between 6.5 and 9 years and at roughly 12 years. The maximum mortality estimates ob…