In the small intestine, type 2 responses are regulated by a signaling circuit that involves tuft cells and group 2 innate lymphoid cells (ILC2s). Here, we identified the microbial metabolite ...succinate as an activating ligand for small intestinal (SI) tuft cells. Sequencing analyses of tuft cells isolated from the small intestine, gall bladder, colon, thymus, and trachea revealed that expression of tuft cell chemosensory receptors is tissue specific. SI tuft cells expressed the succinate receptor (SUCNR1), and providing succinate in drinking water was sufficient to induce a multifaceted type 2 immune response via the tuft-ILC2 circuit. The helminth Nippostrongylus brasiliensis and a tritrichomonad protist both secreted succinate as a metabolite. In vivo sensing of the tritrichomonad required SUCNR1, whereas N. brasiliensis was SUCNR1 independent. These findings define a paradigm wherein tuft cells monitor microbial metabolites to initiate type 2 immunity and suggest the existence of other sensing pathways triggering the response to helminths.
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•Expression of receptors enabling chemosensing on tuft cells is tissue specific•Tuft cells in the small intestine express the succinate receptor SUCNR1•Succinate is sufficient to induce a multifaceted type 2 immune response•Immune sensing of Tritrichomonas colonization by tuft cells requires SUCNR1
Tuft cells have been proposed to act as immune sentinels in multiple tissues. Nadjsombati and McGinty et al. now show that detection of the microbial metabolite succinate by tuft cells in the small intestine is sufficient to induce a type 2 immune response, suggesting that tuft cells monitor microbial metabolites to initiate type 2 immunity.
Black hole feedback in the luminous quasar PDS 456 Nardini, E.; Reeves, J. N.; Gofford, J. ...
Science (American Association for the Advancement of Science),
02/2015, Letnik:
347, Številka:
6224
Journal Article
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Odprti dostop
The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and ...radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband x-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 1046 ergs per second is enough to provide the feedback required by models of black hole and host galaxy coevolution.
Context. The Kilo-Degree Survey (KiDS) is an ongoing optical wide-field imaging survey with the OmegaCAM camera at the VLT Survey Telescope, specifically designed for measuring weak gravitational ...lensing by galaxies and large-scale structure. When completed it will consist of 1350 square degrees imaged in four filters (ugri). Aims. Here we present the fourth public data release which more than doubles the area of sky covered by data release 3. We also include aperture-matched ZYJHKs photometry from our partner VIKING survey on the VISTA telescope in the photometry catalogue. We illustrate the data quality and describe the catalogue content. Methods. Two dedicated pipelines are used for the production of the optical data. The ASTRO-WISE information system is used for the production of co-added images in the four survey bands, while a separate reduction of the r-band images using the THELI pipeline is used to provide a source catalogue suitable for the core weak lensing science case. All data have been re-reduced for this data release using the latest versions of the pipelines. The VIKING photometry is obtained as forced photometry on the THELI sources, using a re-reduction of the VIKING data that starts from the VISTA pawprints. Modifications to the pipelines with respect to earlier releases are described in detail. The photometry is calibrated to the Gaia DR2 G band using stellar locus regression. Results. In this data release a total of 1006 square-degree survey tiles with stacked ugri images are made available, accompanied by weight maps, masks, and single-band source lists. We also provide a multi-band catalogue based on r-band detections, including homogenized photometry and photometric redshifts, for the whole dataset. Mean limiting magnitudes (5σ in a 2″ aperture) and the tile-to-tile rms scatter are 24.23 ± 0.12, 25.12 ± 0.14, 25.02 ± 0.13, 23.68 ± 0.27 in ugri, respectively, and the mean r-band seeing is 0.″70.
We examine the annular mode within each hemisphere (defined here as the leading empirical orthogonal function and principal component of hemispheric sea level pressure) as simulated by the ...Intergovernmental Panel on Climate Change Fourth Assessment Report ensembles of coupled ocean‐atmosphere models. The simulated annular patterns exhibit a high spatial correlation with the observed patterns during the late 20th century, though the mode represents too large a percentage of total temporal variability within each hemisphere. In response to increasing concentrations of greenhouse gases and tropospheric sulfate aerosols, the multimodel average exhibits a positive annular trend in both hemispheres, with decreasing sea level pressure (SLP) over the pole and a compensating increase in midlatitudes. In the Northern Hemisphere, the trend agrees in sign but is of smaller amplitude than that observed during recent decades. In the Southern Hemisphere, decreasing stratospheric ozone causes an additional reduction in Antarctic surface pressure during the latter half of the 20th century. While annular trends in the multimodel average are positive, individual model trends vary widely. Not all models predict a decrease in high‐latitude SLP, although no model exhibits an increase. As a test of the models' annular sensitivity, the response to volcanic aerosols in the stratosphere is calculated during the winter following five major tropical eruptions. The observed response exhibits coupling between stratospheric anomalies and annular variations at the surface, similar to the coupling between these levels simulated elsewhere by models in response to increasing GHG concentration. The multimodel average is of the correct sign but significantly smaller in magnitude than the observed annular anomaly. This suggests that the models underestimate the coupling of stratospheric changes to annular variations at the surface and may not simulate the full response to increasing GHGs.
Objectives We report cancer incidence, mortality, and stage distributions among Asians and Pacific Islanders (API) residing in the U.S. and note health disparities, using the cancer experience of the ...non-Hispanic white population as the referent group. New databases added to publicly available SEER*Stat software will enable public health researchers to further investigate cancer patterns among API groups. Methods Cancer diagnoses among API groups occurring from 1 January 1998 to 31 December 2002 were included from 14 Surveillance, Epidemiology, and End Results (SEER) Program state and regional population-based cancer registries covering 54% of the U.S. API population. Cancer deaths were included from the seven states that report death information for detailed API groups and which cover over 68% of the total U.S. API population. Using detailed racial/ethnic population data from the 2000 decennial census, we produced incidence rates centered on the census year for Asian Indians/Pakistanis, Chinese, Filipinos, Guamanians, Native Hawaiians, Japanese, Kampucheans, Koreans, Laotians, Samoans, Tongans, and Vietnamese. State vital records offices do not report API deaths separately for Kampucheans, Laotians, Pakistanis, and Tongans, so mortality rates were analyzed only for the remaining API groups. Results Overall cancer incidence rates for the API groups tended be lower than overall rates for non-Hispanic whites, with the exception of Native Hawaiian women (All cancers rate = 488.5 per 100,000 vs. 448.5 for non-Hispanic white women). Among the API groups, overall cancer incidence and death rates were highest for Native Hawaiian and Samoan men and women due to high rates for cancers of the prostate, lung, and colorectum among Native Hawaiian men; cancers of the prostate, lung, liver, and stomach among Samoan men; and cancers of the breast and lung among Native Hawaiian and Samoan women. Incidence and death rates for cancers of the liver, stomach, and nasopharynx were notably high in several of the API groups and exceeded rates generally seen for non-Hispanic white men and women. Incidence rates were lowest among Asian Indian/Pakistani and Guamanian men and women and Kampuchean women. Asian Indian and Guamanian men and women also had the lowest cancer death rates. Selected API groups had less favorable distributions of stage at diagnosis for certain cancers than non-Hispanic whites. Conclusions Possible disparities in cancer incidence or mortality between specific API groups in our study and non-Hispanic whites (referent group) were identified for several cancers. Unfavorable patterns of stage at diagnosis for cancers of the colon and rectum, breast, cervix uteri, and prostate suggest a need for cancer control interventions in selected groups. The observed variation in cancer patterns among API groups indicates the importance of monitoring these groups separately, as these patterns may provide etiologic clues that could be investigated by analytic epidemiological studies.
Duplex stainless steels are desirable for use in power generation systems because of their attractive combination of strength, corrosion resistance and cost. However, thermal embrittlement at ...intermediate homologous temperatures of 475 degree C and below, limits upper service temperatures for many applications. New lean grade duplex alloys have improved thermal stability over standard grades and potentially increase the upper service temperature or the lifetime at a given temperature for this class of material. The present work compares the thermal stability of lean grade, alloy 2003, to standard grade, alloy 2205, through a series of isothermal agings between 260 degree C and 482 degree C for times between 1 and 10,000h. Aged samples were characterized by changes in microhardness and impact toughness. Additionally, atom probe tomography was performed to illustrate the evolution of the alpha - alpha ' phase separation in both alloys at select conditions. Atom probe tomography confirmed that phase separation occurs via spinodal decomposition for both alloys, and identified the presence of Ni-Cu-Si-Mn-P clusters in alloy 2205, which may contribute to the embrittlement of this alloy. The impact toughness model predictions for the upper service temperature show that alloy 2003 may be viable for use in 288 degree C applications for 80-year service lifetimes based on a Charpy V-notch criteria of 47J at room temperature. In comparison, alloy 2205 should be limited to 260 degree C applications for the same room temperature toughness of 47J.
Abstract
A critical challenge during volcanic emergencies is responding to rapid changes in eruptive behaviour. Actionable advice, essential in times of rising uncertainty, demands the rapid ...synthesis and communication of multiple datasets with prognoses. The 2020–2021 eruption of La Soufrière volcano exemplifies these challenges: a series of explosions from 9–22 April 2021 was preceded by three months of effusive activity, which commenced with a remarkably low level of detected unrest. Here we show how the development of an evolving conceptual model, and the expression of uncertainties via both elicitation and scenarios associated with this model, were key to anticipating this transition. This not only required input from multiple monitoring datasets but contextualisation via state-of-the-art hazard assessments, and evidence-based knowledge of critical decision-making timescales and community needs. In addition, we share strategies employed as a consequence of constraints on recognising and responding to eruptive transitions in a resource-constrained setting, which may guide similarly challenged volcano observatories worldwide.
The SARS-CoV-2 hyperinflammatory response is associated with high mortality. This hypothesis suggests that a deficiency of nicotinamide adenine dinucleotide (NAD+) may be the primary factor related ...to the SARS-Cov-2 disease spectrum and the risk for mortality, as subclinical nutritional deficiencies may be unmasked by any significant increase in oxidative stress.
NAD+ levels decline with age and are also reduced in conditions associated with oxidative stress as occurs with hypertension, diabetes and obesity. These groups have also been observed to have high mortality following infection with COVID-19. Further consumption of NAD+ in a pre-existent depleted state is more likely to cause progression to the hyperinflammatory stage of the disease through its limiting effects on the production of SIRT1.
This provides a unifying hypothesis as to why these groups are at high risk of mortality and suggests that nutritional support with NAD+ and SIRT1 activators, could minimise disease severity if administered prophylactically and or therapeutically. The significance of this, if proven, has far-reaching consequences in the management of COVID-19 especially in third world countries, where resources and finances are limited.
Iron speciation is one of the most widely applied proxies used to reconstruct oxygen levels and redox conditions in past aqueous environments. The iron speciation proxy estimates proportions of ...different reactive iron species in fine‐grained sedimentary rocks, which are mapped to redox conditions based on empirical calibrations from modern sediments. It is based on a standardized extraction technique of sequentially applying acetate, hydroxlamine‐HCl, dithionite, and oxalate solutions to a powdered sample in order to dissolve iron phases and quantify the amount of iron carried by carbonates, “easily reducible” oxyhydroxides, ferric iron (oxyhydr)oxides, and magnetite, respectively. Although tested on pure minerals and mixtures, assessments of whether this sequential extraction process accurately dissolves the targeted minerals in natural sediments and sedimentary rocks are lacking. In our study, residues from each sequential extraction step were analyzed using rock magnetic and X‐ray diffraction experiments to identify and quantify the iron‐bearing minerals that were dissolved. The dithionite extraction robustly removes the targeted mineralogy as magnetic data show it to solubilize nearly all of the goethite. However, magnetic quantification of magnetite was orders of magnitude less than the iron measured in the oxalate extraction; X‐ray diffraction data suggest that dissolution of iron‐bearing clays, specifically berthierine/chamosite, could explain this disparity. Our data compilation shows higher values of iron from the oxalate extraction in Precambrian sedimentary rock samples, suggesting a significant temporal shift in iron cycling. Recognition of heterogeneity in chemical extraction efficiency and targeting is vital for holistic multiproxy interpretation of past oxygen levels and communication between disciplines.
Plain Language Summary
Sequential chemical extractions, where a series of solutions are applied to a powdered rock sample to selectively dissolve certain phases, are heavily utilized throughout Earth Science research. These methodologies provide a tool for estimating different reactive forms of an element; understanding how these pools change over time in a given environment allows us to better understand cycling of the element by biological, chemical, and geologic processes on the Earth's surface. In this study, we focus on a sequential chemical extraction method that measures the element iron, the most abundant transition metal in Earth's crust. Although heavily utilized for understanding nutrient cycling and ancient oxygen levels, the method is largely untested using actual rock samples that contain a mixture of minerals of different shapes and sizes. Such tests are needed to evaluate whether the extractions are accurately and completely dissolving the targeted minerals. We utilized magnetic and X‐ray diffraction methods that can sensitively measure iron minerals within natural samples. We found that some of the extractions worked as expected, but others did not, dissolving additional unexpected mineral types and/or slowly dissolving minerals across multiple extractions.
Key Points
Magnetic and X‐ray diffraction analyses on natural samples corroborate the efficiency of certain chemical extractions, such as dithionite
The majority of iron in the oxalate extraction is not dissolved from magnetite, but instead comes from iron‐bearing clays
Recognition of the heterogeneity in chemical extraction efficiency and targeting is vital for studies of past and present iron cycling
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