410 research outputs found
Nemo-like kinase regulates the expression of vascular endothelial growth factor (VEGF) lein alveolar epithelial cells
The canonical Wnt signaling can be silenced either through β-catenin-mediated ubiquitination and degradation or through phosphorylation of Tcf and Lef by nemo-like kinase (NLK). In the present study, we generated NLK deficient animals and found that these mice become cyanotic shortly before death because of lung maturation defects. NLK-/- lungs exhibited smaller and compressed alveoli and the mesenchyme remained thick and hyperplastic. This phenotype was caused by epithelial activation of vascular endothelial growth factor (VEGF) via recruitment of Lef1 to the promoter of VEGF. Elevated expression of VEGF and activation of the VEGF receptor through phosphorylation promoted an increase in the proliferation rate of epithelial and endothelial cells. In summary, our study identifies NLK as a novel signaling molecule for proper lung development through the interconnection between epithelial and endothelial cells during lung morphogenesis
"Girls can't play": The effects of stereotype threat on females' gaming performance
The current study examined the impact of stereotype threat on female online gamers' performance and further examined whether manipulating the availability of multiple social identities effectively eliminated these performance decrements. Further, participants' implicit attitudes towards female online gamers were assessed. Eighty-one participants (60 female) were assigned to one of four experimental conditions: 1), stereotype threat, 2), multiple social identities, 3), female control, and 4), male control. They completed an Implicit Association Test and a gaming task. The number of coins collected in a 5-min time period provided a measure of gameplay performance. Results indicated that stereotype threatened females underperformed on the gaming task relative to males in the control condition. The intervention of multiple social identities successfully protected females' gameplay performance from stereotype threat. Additionally, differences were found between conditions in implicit attitudes pertaining to gender-gaming competence. This research highlights the harmful effects of negative stereotypes on females' gaming performance, and suggests that these decrements may be eliminated when females identify with an alternative positive social identity
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Guidelines for consideration of bats in lighting projects.
Eighty percent of the world’s population are currently exposed to light-polluted skies, and the Milky Way is no longer visible to more than a third of humanity. The pace the light pollution is increasing is faster than global population growth and economic development. While environmental conditions at night are being dramatically and rapidly altered, circadian rhythms, behaviour and ecology of plants and animals are imminently influenced. In the same time, effects of artificial lighting, various illumination schemes and spectra on biodiversity, including bats, are currently insufficiently understood, whereas only a vague notion of required mitigation and compensation activities exists among decision-makers and other parties involved in lighting projects. Although the bats are almost exclusively nocturnal and extremely sensitive to multiple effects of light pollution, its negative impact on bats alongside essential measures needed to preserve unfragmented nightscapes for these animals are often disregarded during impact assessments, planning and operation.
In this volume, we tried to compile available evidence related to the effect of artificial light at night on the European bats. Based on the current state of knowledge, solutions are proposed concerning possible ways to avoid, mitigate and compensate the adverse effects which lighting projects may have on bats and their functional habitats. We also outlined research priorities for future studies, required for in-depth understanding of the problem and assessing efficiency of proposed mitigative measures
Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
BACKGROUND: During a lipopolysaccharide-induced lung inflammation, a massive accumulation of neutrophils occurs, which is normally cleared by macrophage phagocytosis following neutrophil apoptosis. However, in cases of extensive apoptosis the normal clearance system may fail, resulting in extensive neutrophil secondary necrosis. The aim of this study was to explore the hypothesis that neutrophils, in areas of the lung with extensive cellular infiltration, contribute to clearance by phagocytosing apoptotic cells and/or cell debris derived from secondary necrosis. METHODS: Intranasal lipopolysaccharide administration was used to induce lung inflammation in mice. The animals were sacrificed at seven time points following administration, bronchoalveolar lavage was performed and tissue samples obtained. Electron microscopy and histochemistry was used to assess neutrophil phagocytosis. RESULTS: Electron microscopic studies revealed that phagocytosing neutrophils was common, at 24 h after LPS administration almost 50% of the total number of neutrophils contained phagosomes, and the engulfed material was mainly derived from other neutrophils. Histochemistry on bronchoalvolar lavage cells further showed phagocytosing neutrophils to be frequently occurring. CONCLUSION: Neutrophils are previously known to phagocytose invading pathogens and harmful particles. However, this study demonstrates that neutrophils are also able to engulf apoptotic neutrophils or cell debris resulting from secondary necrosis of neutrophils. Neutrophils may thereby contribute to clearance and resolution of inflammation, thus acting as a back up system in situations when the macrophage clearance system is insufficient and/or overwhelmed
Throat related symptoms and voice: development of an instrument for self assessment of throat-problems
<p>Abstract</p> <p>Background</p> <p>Symptoms from throat (sensation of globus; frequent throat clearing; irritated throat) are common in patients referred to voice clinics and to ENT specialists. The relation to symptoms of voice discomfort is unclear and in some cases patients do not have voice problems at all. Instruments for patients' self-reporting of symptoms, and assessment of handicap, such as the Voice Handicap Index (VHI), are in common use in voice clinics. Symptoms from throat are however only marginally covered. Purpose: To develop and evaluate an instrument that could make the patients' estimation of symptoms from the throat possible. Further to facilitate the consideration of the relation between throat- and voice problems with the Throat subscale together with a Swedish translation of the Voice Handicap Index. Finally to try the VHI with the Throat subscale: the VHI-T, for test-retest reliability and validity.</p> <p>Methods</p> <p>A subscale with 10 throat related items was developed for appliance with the VHI. The VHI was translated to Swedish and retranslated to English. The questionnaire was tried in two phases on a total of 23+144 patients and 12+58 voice healthy controls. The reliability was calculated with Cronbach's alpha, ICC and Pearson's correlation coefficient. The validity was estimated by independent T-test.</p> <p>Results</p> <p>The difference in VHI-T scores between the patients and the voice-healthy controls was significant (<it>p </it>= < 0,01) and there was a good correlation of the test- retest occasions. The reliability testing of the entire questionnaire showed an alpha value of <it>r </it>= 0,90 and that for the Throat subscale separately a value of <it>r </it>= 0,87 which shows a high degree of reliability.</p> <p>Conclusions</p> <p>For the estimation of self-perceived throat and voice problems the scale on throat related problems together with the present Swedish translation of the Voice Handicap Index, (VHI) the VHI-Throat, proves to be a valid and reliable instrument. The throat subscale seems to help revealing a category of symptoms that are common in our patients. These are symptoms that have not earlier been possible to cover with the questionnaires designed for use in the voice clinic.</p
Preparation and characterization of starch-poly-epsilon-caprolactone microparticles incorporating bioactive agents for drug delivery and tissue engineering applications
One limitation associated with the delivery of bioactive agents concerns the short half-life of these molecules when administered intravenously,
which results in their loss from the desired site. Incorporation of bioactive agents into depot vehicles provides a means to
increase their persistence at the disease site. Major issues are involved in the development of a proper carrier system able to deliver
the correct drug, at the desired dose, place and time. In this work, starch-poly-e-caprolactone (SPCL) microparticles were developed
for use in drug delivery and tissue engineering (TE) applications. SPCL microparticles were prepared by using an emulsion solvent
extraction/evaporation technique, which was demonstrated to be a successful procedure to obtain particles with a spherical shape (particle
size between 5 and 900 lm) and exhibiting different surface morphologies. Their chemical structure was confirmed by Fourier transform
infrared spectroscopy. To evaluate the potential of the developed microparticles as a drug delivery system, dexamethasone (DEX)
was used as model drug. DEX, a well-known component of osteogenic differentiation media, was entrapped into SPCL microparticles at
different percentages up to 93%. The encapsulation efficiency was found to be dependent on the polymer concentration and drug-to-polymer
ratio. The initial DEX release seems to be governed mainly by diffusion, and it is expected that the remaining DEX will be released
when the polymeric matrix starts to degrade. In this work it was demonstrated that SPCL microparticles containing DEX can be successfully
prepared and that these microparticular systems seem to be quite promising for controlled release applications, namely as carriers
of important differentiation agents in TE.E.R.B. thanks the Marie Curie Host Fellowships for Early Stage Research Training (EST) "Alea Jacta EST" (MEST-CT-2004-008104) for providing her with a PhD Fellowship. This work was partially supported by the European NoE EXPERTISSUES (NMP3-CT-2004-500283)
Ensemble Composition and Activity Levels of Insectivorous Bats in Response to Management Intensification in Coffee Agroforestry Systems
Shade coffee plantations have received attention for their role in biodiversity conservation. Bats are among the most diverse mammalian taxa in these systems; however, previous studies of bats in coffee plantations have focused on the largely herbivorous leaf-nosed bats (Phyllostomidae). In contrast, we have virtually no information on how ensembles of aerial insectivorous bats – nearly half the Neotropical bat species – change in response to habitat modification. To evaluate the effects of agroecosystem management on insectivorous bats, we studied their diversity and activity in southern Chiapas, Mexico, a landscape dominated by coffee agroforestry. We used acoustic monitoring and live captures to characterize the insectivorous bat ensemble in forest fragments and coffee plantations differing in the structural and taxonomic complexity of shade trees. We captured bats of 12 non-phyllostomid species; acoustic monitoring revealed the presence of at least 12 more species of aerial insectivores. Richness of forest bats was the same across all land-use types; in contrast, species richness of open-space bats increased in low shade, intensively managed coffee plantations. Conversely, only forest bats demonstrated significant differences in ensemble structure (as measured by similarity indices) across land-use types. Both overall activity and feeding activity of forest bats declined significantly with increasing management intensity, while the overall activity, but not feeding activity, of open-space bats increased. We conclude that diverse shade coffee plantations in our study area serve as valuable foraging and commuting habitat for aerial insectivorous bats, and several species also commute through or forage in low shade coffee monocultures
Ensemble Composition and Activity Levels of Insectivorous Bats in Response to Management Intensification in Coffee Agroforestry Systems
Shade coffee plantations have received attention for their role in biodiversity conservation. Bats are among the most diverse mammalian taxa in these systems; however, previous studies of bats in coffee plantations have focused on the largely herbivorous leaf-nosed bats (Phyllostomidae). In contrast, we have virtually no information on how ensembles of aerial insectivorous bats – nearly half the Neotropical bat species – change in response to habitat modification. To evaluate the effects of agroecosystem management on insectivorous bats, we studied their diversity and activity in southern Chiapas, Mexico, a landscape dominated by coffee agroforestry. We used acoustic monitoring and live captures to characterize the insectivorous bat ensemble in forest fragments and coffee plantations differing in the structural and taxonomic complexity of shade trees. We captured bats of 12 non-phyllostomid species; acoustic monitoring revealed the presence of at least 12 more species of aerial insectivores. Richness of forest bats was the same across all land-use types; in contrast, species richness of open-space bats increased in low shade, intensively managed coffee plantations. Conversely, only forest bats demonstrated significant differences in ensemble structure (as measured by similarity indices) across land-use types. Both overall activity and feeding activity of forest bats declined significantly with increasing management intensity, while the overall activity, but not feeding activity, of open-space bats increased. We conclude that diverse shade coffee plantations in our study area serve as valuable foraging and commuting habitat for aerial insectivorous bats, and several species also commute through or forage in low shade coffee monocultures
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