560 research outputs found
Multi-photon attenuation-compensated light-sheet fluorescence microscopy
We thank the UK Engineering and Physical Sciences Research Council for funding (grants EP/P030017/1 and EP/R004854/1), the European Union’s Horizon 2020 Framework Programme (H2020) (675512, BE-OPTICAL), the Danish Council for Independent Research (DFF FTP grant 7017-00021), and the Otto Mønsted Foundation (grant 19-70-0109).Attenuation of optical fields owing to scattering and absorption limits the penetration depth for imaging. Whilst aberration correction may be used, this is difficult to implement over a large field-of-view in heterogeneous tissue. Attenuation-compensation allows tailoring of the maximum lobe of a propagation-invariant light field and promises an increase in depth penetration for imaging. Here we show this promising approach may be implemented in multi-photon (two-photon) light-sheet fluorescence microscopy and, furthermore, can be achieved in a facile manner utilizing a graded neutral density filter, circumventing the need for complex beam shaping apparatus. A “gold standard” system utilizing a spatial light modulator for beam shaping is used to benchmark our implementation. The approach will open up enhanced depth penetration in light-sheet imaging to a wide range of end users.Publisher PDFPeer reviewe
Socioeconomic considerations in the health of urban areas
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45780/1/11524_2006_Article_BF02345090.pd
Recent Walker Circulation strengthening and Pacific cooling amplified by Atlantic warming
An unprecedented strengthening of Pacific trade winds since the late 1990s (ref. 1) has caused widespread climate perturbations, including rapid sea-level rise in the western tropical Pacific, strengthening of Indo-Pacific ocean currents, and an increased uptake of heat in the equatorial Pacific thermocline. The corresponding intensification of the atmospheric Walker circulation is also associated with sea surface cooling in the eastern Pacific, which has been identified as one of the contributors to the current pause in global surface warming. In spite of recent progress in determining the climatic impacts of the Pacific trade wind acceleration, the cause of this pronounced trend in atmospheric circulation remains unknown. Here we analyse a series of climate model experiments along with observational data to show that the recent warming trend in Atlantic sea surface temperature and the corresponding trans-basin displacements of the main atmospheric pressure centres were key drivers of the observed Walker circulation intensification, eastern Pacific cooling, North American rainfall trends and western Pacific sea-level rise. Our study suggests that global surface warming has been partly offset by the Pacific climate response to enhanced Atlantic warming since the early 1990s
Beyond the brain-Peripheral kisspeptin signaling is essential for promoting endometrial gland development and function
Uterine growth and endometrial gland formation (adenogenesis) and function, are essential for fertility and are controlled by estrogens and other regulators, whose nature and physiological relevance are yet to be elucidated. Kisspeptin, which signals via Kiss1r, is essential for fertility, primarily through its central control of the hypothalamic-pituitary-ovarian axis, but also likely through peripheral actions. Using genetically modified mice, we addressed the contributions of central and peripheral kisspeptin signaling in regulating uterine growth and adenogenesis. Global ablation of Kiss1 or Kiss1r dramatically suppressed uterine growth and almost fully prevented adenogenesis. However, while uterine growth was fully rescued by E2 treatment of Kiss1(-/-) mice and by genetic restoration of kisspeptin signaling in GnRH neurons in Kiss1r(-/-) mice, functional adenogenesis was only marginally restored. Thus, while uterine growth is largely dependent on ovarian E2-output via central kisspeptin signaling, peripheral kisspeptin signaling is indispensable for endometrial adenogenesis and function, essential aspects of reproductive competence
Causes and Treatment Outcomes of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in 82 Adult Patients
original article korean j intern med 2012;27:203-21
Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model
Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures
Demographic, social cognitive and social ecological predictors of intention and participation in screening for colorectal cancer
Extent: 10p.Background: Previous research points to differences between predictors of intention to screen for colorectal cancer (CRC) and screening behavior, and suggests social ecological factors may influence screening behavior. The aim of this study was to compare the social cognitive and social ecological predictors of intention to screen with predictors of participation. Methods: People aged 50 to 74 years recruited from the electoral roll completed a baseline survey (n = 376) and were subsequently invited to complete an immunochemical faecal occult blood test (iFOBT). Results: Multivariate analyses revealed five predictors of intention to screen and two predictors of participation. Perceived barriers to CRC screening and perceived benefits of CRC screening were the only predictor of both outcomes. There was little support for social ecological factors, but measurement problems may have impacted this finding. Conclusions: This study has confirmed that the predictors of intention to screen for CRC and screening behaviour, although overlapping, are not the same. Research should focus predominantly on those factors shown to predict participation. Perceptions about the barriers to screening and benefits of screening are key predictors of participation, and provide a focus for intervention programs.Tess A Gregory, Carlene Wilson, Amy Duncan, Deborah Turnbull, Stephen R Cole and Graeme Youn
Thyroid and pituitary gland development from hatching through metamorphosis of a teleost flatfish, the Atlantic halibut
Fish larval development, not least the spectacular
process of flatfish metamorphosis, appears to be
under complex endocrine control, many aspects of
which are still not fully elucidated. In order to obtain
data on the functional development of two major
endocrine glands, the pituitary and the thyroid, during
flatfish metamorphosis, histology, immunohistochemistry
and in situ hybridization techniques were applied on
larvae of the Atlantic halibut (Hippoglossus hippoglossus),
a large, marine flatfish species, from hatching
through metamorphosis. The material was obtained
from a commercial hatchery. Larval age is defined as
day-degrees (D =accumulated daily temperature from
hatching). Sporadic thyroid follicles are first detected in
larvae at 142 D (27 days post-hatch), prior to the
completion of yolk sack absorption. Both the number
and activity of the follicles increase markedly after yolk
sack absorption and continue to do so during subsequent
development. The larval triiodothyronine (T3)
and thyroxine (T4) content increases, subsequent to yolk
absorption, and coincides with the proliferation of thyroid
follicles. A second increase of both T3 and T4 occurs
around the start of metamorphosis and the T3 content
further increases at the metamorphic climax. Overall,
the T3 content is lower than T4. The pituitary gland can
first be distinguished as a separate organ at the yolk sack
stage. During subsequent development, the gland becomes
more elongated and differentiates into neurohypophysis (NH), pars distalis (PD) and pars intermedia
(PI). The first sporadic endocrine pituitary cells are observed
at the yolk sack stage, somatotrophs (growth
hormone producing cells) and somatolactotrophs (somatolactin
producing cells) are first observed at 121 D
(23 days post-hatch), and lactotrophs (prolactin producing
cells) at 134 D (25 days post-hatch). Scarce
thyrotrophs are evident after detection of the first thyroid
follicles (142 D ), but coincident with a phase in
which follicle number and activity increase (260 D ).
The somatotrophs are clustered in the medium ventral
region of the PD, lactotrophs in the anterior part of the
PD and somatolactotrophs are scattered in the mid and
posterior region of the pituitary. At around 600 D ,
coinciding with the start of metamorphosis, somatolactotrophs
are restricted to the interdigitating tissue of the
NH. During larval development, the pituitary endocrine
cells become more numerous. The present data on thyroid
development support the notion that thyroid hormones
may play a significant role in Atlantic halibut
metamorphosis. The time of appearance and the subsequent
proliferation of pituitary somatotrophs, lactotrophs,
somatolactotrophs and thyrotrophs indicate at
which stages of larval development and metamorphosis
these endocrine cells may start to play active regulatory
roles.This work has been carried out within the
projects ‘‘Endocrine Control as a Determinant of Larval Quality in
Fish Aquaculture’’ (CT-96-1422) and ‘‘Arrested development: The
Molecular and Endocrine Basis of Flatfish Metamorphosis’’
(Q5RS-2002-01192), with financial support from the Commission
of the European Communities. However, it does not necessarily
reflect the Commission’s views and in no way anticipates its future
policy in this area. This project was further supported by the
Swedish Council for Agricultural and Forestry Research and Pluriannual
funding to CCMAR by the Portuguese Science and
Technology Council
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