ABSTRACT
The analytic galactic wind model derived by Chevalier and Clegg in 1985 (CC85) assumes uniform energy and mass-injection within the starburst galaxy nucleus. However, the structure of ...nuclear star clusters, bulges, and star-forming knots are non-uniform. We generalize to cases with spherically-symmetric energy/mass injection that scale as r−Δ within the starburst volume R, providing solutions for Δ = 0, 1/2, 1, 3/2, and 2. In marked contrast with the CC85 model (Δ = 0), which predicts zero velocity at the centre, for a singular isothermal sphere profile (Δ = 2), we find that the flow maintains a constant Mach number of $\mathcal {M}=\sqrt{3/5} \simeq 0.77$ throughout the volume. The fast interior flow can be written as $v_{r \lt R} = (\dot{E}_T/3\dot{M}_T)^{1/2} \simeq 0.41 \, v_\infty$, where v∞ is the asymptotic velocity, and $\dot{E}_T$ and $\dot{M}_T$ are the total energy and mass injection rates. For $v_\infty \simeq 2000 \, \mathrm{km \, s^{-1}}$, $v_{r\lt R} \simeq 820 \, \mathrm{km\, s^{-1}}$ throughout the wind-driving region. The temperature and density profiles of the non-uniform models may be important for interpreting spatially-resolved maps of starburst nuclei. We compute velocity resolved spectra to contrast the Δ = 0 (CC85) and Δ = 2 models. Next generation X-ray space telescopes such as XRISM may assess these kinematic predictions.
Stellar feedback is often cited as the biggest uncertainty in galaxy formation models today. This uncertainty stems from a dearth of observational constraints as well as the great dynamic range ...between the small scales (lap1 pc) where the feedback originates and the large scales of galaxies (gap1 kpc) that are shaped by this feedback. To bridge this divide, in this paper we aim to assess observationally the role of stellar feedback at the intermediate scales of HII regions (~10-100 pc). In particular, we employ multiwavelength data to examine several stellar feedback mechanisms in a sample of 32 HII regions (with ages ~3-10 Myr) in the Large and Small Magellanic Clouds, respectively. Using optical, infrared, radio, and X-ray images, we measure the pressures exerted on the shells from the direct stellar radiation, the dust-processed radiation, the warm ionized gas, and the hot X-ray-emitting gas. We find that the warm ionized gas dominates over the other terms in all of the sources, although two have comparable dust-processed radiation pressures to their warm gas pressures. The hot gas pressures are comparatively weak, while the direct radiation pressures are one to two orders of magnitude below tire other terms. We discuss the implications of these results, particularly highlighting evidence for hot gas leakage from the HII shells and regarding the momentum deposition from the dust-processed radiation to the warm gas. Furthermore, we emphasize that similar observational work should be done on very young HII regions to test whether direct radiation pressure and hot gas can drive the dynamics at early times.
Genistein is an isoflavone present in soybeans and is considered a bioactive compound due to its widely reported biological activity. We have previously shown that intraperitoneal genistein ...administration and diet supplementation activates the thermogenic program in rats and mice subcutaneous white adipose tissue (scWAT) under multiple environmental cues, including cold exposure and high‐fat diet feeding. However, the mechanistic insights of this process were not previously unveiled. Uncoupling protein 1 (UCP1), a mitochondrial membrane polypeptide responsible for dissipating energy into heat, is considered the most relevant thermogenic marker; thus, we aimed to evaluate whether genistein regulates UCP1 transcription. Here we show that genistein administration to thermoneutral‐housed mice leads to the appearance of beige adipocyte markers, including a sharp upregulation of UCP1 expression and protein abundance in scWAT. Reporter assays showed an increase in UCP1 promoter activity after genistein stimulation, and in silico analysis revealed the presence of estrogen (ERE) and cAMP (CRE) response elements as putative candidates of genistein activation. Mutation of the CRE but not the ERE reduced genistein‐induced promoter activity by 51%. Additionally, in vitro and in vivo ChIP assays demonstrated the binding of CREB to the UCP1 promoter after acute genistein administration. Taken together, these data elucidate the mechanism of genistein‐mediated UCP1 induction and confirm its potential applications in managing metabolic disorders.
Genistein induces the thermogenic program in white adipose tissue via cAMP/PKA/CREB pathway to promote Ucp1 transcription. This mechanism of beige remodeling is independent of sympathetic nervous system activation.
Vibrational spectroscopy techniques are widely used in analytical chemistry, physics and biology. The most prominent techniques are Raman and Fourier-transform infrared spectroscopy (FTIR). Combining ...both techniques delivers complementary information of the test sample. We present the design, construction, and calibration of a novel bimodal spectroscopy system featuring both Raman and infrared measurements simultaneously on the same sample without mutual interference. The optomechanical design provides a modular flexible system for solid and liquid samples and different configurations for Raman. As a novel feature, the Raman module can be operated off-axis for optical sectioning. The calibrated system demonstrates high sensitivity, precision, and resolution for simultaneous operation of both techniques and shows excellent calibration curves with coefficients of determination greater than 0.96. We demonstrate the ability to simultaneously measure Raman and infrared spectra of complex biological material using bovine serum albumin. The performance competes with commercial systems; moreover, it presents the additional advantage of simultaneously operating Raman and infrared techniques. To the best of our knowledge, it is the first demonstration of a combined Raman-infrared system that can analyze the same sample volume and obtain optically sectioned Raman signals. Additionally, quantitative comparison of confocality of backscattering micro-Raman and off-axis Raman was performed for the first time.
Existence of anthropogenic contaminants (ACs) in different environmental matrices is a serious and unresolved concern. For instance, ACs from different sectors, such as industrial, agricultural, and ...pharmaceutical, are found in water bodies with considerable endocrine disruptors potency and can damage the biotic components of the environment. The continuous ACs exposure can cause cellular toxicity, apoptosis, genotoxicity, and alterations in sex ratios in human beings. Whereas, aquatic organisms show bioaccumulation, trophic chains, and biomagnification of ACs through different entry route. These problems have been found in many countries around the globe, making them a worldwide concern. ACs have been found in different environmental matrices, such as water reservoirs for human consumption, wastewater treatment plants (WWTPs), drinking water treatment plants (DWTPs), groundwaters, surface waters, rivers, and seas, which demonstrate their free movement within the environment in an uncontrolled manner. This work provides a detailed overview of ACs occurrence in water bodies along with their toxicological effect on living organisms. The literature data reported between 2017 and 2018 is compiled following inclusion-exclusion criteria, and the obtained information was mapped as per type and source of ACs. The most important ACs are pharmaceuticals (diclofenac, ibuprofen, naproxen, ofloxacin, acetaminophen, progesterone ranitidine, and testosterone), agricultural products or pesticides (atrazine, carbendazim, fipronil), narcotics and illegal drugs (amphetamines, cocaine, and benzoylecgonine), food industry derivatives (bisphenol A, and caffeine), and personal care products (triclosan, and other related surfactants). Considering this threatening issue, robust detection and removal strategies must be considered in the design of WWTPs and DWTPs.
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•Data of global occurrence of ACs in water resources from 2017 to 2018 was mapped.•Adverse effects of ACs on living organisms in polluted environments were analyzed.•ACs occurrence in drinking water reservoirs and bottled water was discussed.•Challenges and perspectives of ACs occurrence within water bodies are presented.
Obesity and its comorbidities are a severe public health problem worldwide. The use of bioactive compounds found in some foods has been demonstrated to ameliorate the metabolic abnormalities ...associated with obesity. The purpose of this study was to assess whether the bioactive compounds present in aguamiel concentrate (AC) from Agave salmiana could attenuate glucose intolerance and hepatic steatosis in mice fed a high fat (HF) diet. HPLC-ELSD analysis showed that AC contained several saponins. The consumption of an AC extract rich in saponins reduced weight gain and fat mass and lowered serum glucose, insulin and LDL-cholesterol levels in mice fed a HF diet. Additionally, mice fed the saponin extract exhibited a reduced HOMA index and hepatic lipid levels and increased expression of genes involved in fatty acid oxidation. Saponins increased white adipose tissue browning, AMPK phosphorylation, fatty acid oxidation, and mitochondrial activity in skeletal muscle and energy expenditure in mice fed the HF diet. These metabolic changes were accompanied by an increase in the abundance of Akkermansia muciniphila in the gut microbiota. Therefore, Agave salmiana saponins can be an alternative to attenuate the metabolic changes that accompany obesity.
Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and ...bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa's ability to colonize the GI tract but does decrease P. aeruginosa's cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
The PHANGS program is building the first data set to enable the multiphase, multiscale study of star formation across the nearby spiral galaxy population. This effort is enabled by large ...survey programs with the Atacama Large Millimeter/submillimeter Array (ALMA), MUSE on the Very Large Telescope, and the Hubble Space Telescope (HST), with which we have obtained CO(2–1) imaging, optical spectroscopic mapping, and high-resolution UV–optical imaging, respectively. Here, we present PHANGS-HST, which has obtained NUV–
U
–
B
–
V
–
I
imaging of the disks of 38 spiral galaxies at distances of 4–23 Mpc, and parallel
V
- and
I
-band imaging of their halos, to provide a census of tens of thousands of compact star clusters and multiscale stellar associations. The combination of HST, ALMA, and VLT/MUSE observations will yield an unprecedented joint catalog of the observed and physical properties of ∼100,000 star clusters, associations, H
ii
regions, and molecular clouds. With these basic units of star formation, PHANGS will systematically chart the evolutionary cycling between gas and stars across a diversity of galactic environments found in nearby galaxies. We discuss the design of the PHANGS-HST survey and provide an overview of the HST data processing pipeline and first results. We highlight new methods for selecting star cluster candidates, morphological classification of candidates with convolutional neural networks, and identification of stellar associations over a range of physical scales with a watershed algorithm. We describe the cross-observatory imaging, catalogs, and software products to be released. The PHANGS high-level science products will seed a broad range of investigations, in particular, the study of embedded stellar populations and dust with the James Webb Space Telescope, for which a PHANGS Cycle 1 Treasury program to obtain eight-band 2–21
μ
m imaging has been approved.
The relatively high level of morphological diversity in Australasian marsupials compared to that observed among American marsupials remains poorly understood. We undertake a comprehensive ...macroevolutionary analysis of ontogenetic allometry of American and Australasian marsupials to examine whether the contrasting levels of morphological diversity in these groups are reflected in their patterns of allometric evolution. We collate ontogenetic series for 62 species and 18 families of marsupials (n = 2091 specimens), spanning across extant marsupial diversity. Our results demonstrate significant lability of ontogenetic allometric trajectories among American and Australasian marsupials, yet a phylogenetically structured pattern of allometric evolution is preserved. Here we show that species diverging more than 65 million years ago converge in their patterns of ontogenetic allometry under animalivorous and herbivorous diets, and that Australasian marsupials do not show significantly greater variation in patterns of ontogenetic allometry than their American counterparts, despite displaying greater magnitudes of extant ecomorphological diversity.
Abstract
We present the discovery that ASASSN-14ko is a periodically flaring active galactic nucleus at the center of the galaxy ESO 253-G003. At the time of its discovery by the All-Sky Automated ...Survey for Supernovae (ASAS-SN), it was classified as a supernova close to the nucleus. The subsequent 6 yr of
V
- and
g
-band ASAS-SN observations revealed that ASASSN-14ko has nuclear flares occurring at regular intervals. The 17 observed outbursts show evidence of a decreasing period over time, with a mean period of
P
0
= 114.2 ± 0.4 days and a period derivative of
. The most recent outburst in 2020 May, which took place as predicted, exhibited spectroscopic changes during the rise and had a UV bright, blackbody spectral energy distribution similar to tidal disruption events (TDEs). The X-ray flux decreased by a factor of 4 at the beginning of the outburst and then returned to its quiescent flux after ∼8 days. The Transiting Exoplanet Survey Satellite observed an outburst during Sectors 4–6, revealing a rise time of 5.60 ± 0.05 days in the optical and a decline that is best fit with an exponential model. We discuss several possible scenarios to explain ASASSN-14ko’s periodic outbursts, but currently favor a repeated partial TDE. The next outbursts should peak in the optical on UT 2020 September 7.4±1.1 and UT 2020 December 26.5±1.4.
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