Oleanolic acid, a pentacyclic triterpenoid ubiquitously present in the plant kingdom, is receiving outstanding attention from the scientific community due to its biological activity against multiple ...diseases. Oleanolic acid is endowed with a wide range of biological activities with therapeutic potential by means of complex and multifactorial mechanisms. There is evidence suggesting that oleanolic acid might be effective against dyslipidemia, diabetes and metabolic syndrome, through enhancing insulin response, preserving the functionality and survival of β-cells and protecting against diabetes complications. In addition, several other functions have been proposed, including antiviral, anti-HIV, antibacterial, antifungal, anticarcinogenic, anti-inflammatory, hepatoprotective, gastroprotective, hypolipidemic and anti-atherosclerotic activities, as well as interfering in several stages of the development of different types of cancer; however, due to its hydrophobic nature, oleanolic acid is almost insoluble in water, which has led to a number of approaches to enhance its biopharmaceutical properties. In this scenario, the present review aimed to summarize the current knowledge and the research progress made in the last years on the extraction and characterization of oleanolic acid and its biological activities and the underlying mechanisms of action.
Abstract Despite encouraging advances in prevention and treatment of atherothrombosis, cardiovascular disease (CVD) remains a major cause of deaths and disability worldwide and will continue to grow ...mainly due to the increase in incidence in low and middle income countries (LMIC). In Europe and the United States of America (USA), coronary heart disease (CHD) mortality rates have decreased since the mid-1990s due to improvements in acute care, however the prevalence of CHD is increasing largely in part due to the overall aging of the population, increased prevalence of cardiovascular (CV) risk factors, and improved survival of patients after a CV event. Data from clinical trials has consistently proven the efficacy of pharmacologic interventions with aspirin, statins, and blood pressure (BP)-lowering agents in reducing the risk of CV events and total mortality in the ever growing pool of patients in secondary prevention. However, large gaps between indicated therapy and prescribed medication can be observed worldwide, with very low rates of use of effective therapies in LMIC countries. Adherence to medication is very poor in chronic patients, especially those treated with multiple pharmacologic agents, and has been directly correlated to a greater incidence of recurrent CV events and increase in direct and indirect healthcare costs. In this article, we review the global burden of CV disease, status of secondary prevention therapy and major barriers for treatment adherence.
Abstract
The GLASS-JWST Early Release Science (hereafter GLASS-JWST-ERS) Program will obtain and make publicly available the deepest extragalactic data of the ERS campaign. It is primarily designed ...to address two key science questions, namely, “what sources ionized the universe and when?” and “how do baryons cycle through galaxies?”, while also enabling a broad variety of first look scientific investigations. In primary mode, it will obtain NIRISS and NIRSpec spectroscopy of galaxies lensed by the foreground Hubble Frontier Field cluster, Abell 2744. In parallel, it will use NIRCam to observe two fields that are offset from the cluster center, where lensing magnification is negligible, and which can thus be effectively considered blank fields. In order to prepare the community for access to this unprecedented data, we describe the scientific rationale, the survey design (including target selection and observational setups), and present pre-commissioning estimates of the expected sensitivity. In addition, we describe the planned public releases of high-level data products, for use by the wider astronomical community.
ABSTRACT
We search the five CANDELS fields (COSMOS, EGS, GOODS-North, GOODS-South, and UDS) for passively evolving a.k.a. ‘red and dead’ massive galaxies in the first 2 Gyr after the big bang, ...integrating and updating the work on GOODS-South presented in a previous paper. We perform SED-fitting on photometric data, with top-hat star-formation histories to model an early and abrupt quenching, and using a probabilistic approach to select only robust candidates. Using libraries without (with) spectral lines emission, starting from a total of more than 20 000 z > 3 sources we end up with 102 (40) candidates, including one at z = 6.7. This implies a minimal number density of 1.73 ± 0.17 × 10−5 (6.69 ± 1.08 × 10−6) Mpc−3 for 3 < z < 5; applying a correction factor to account for incompleteness yields 2.30 ± 0.20 × 10−5. We compare these values with those from five recent hydrodynamical cosmological simulations, finding a reasonable agreement at z < 4; tensions arise at earlier epochs. Finally, we use the star-formation histories from the best-fitting models to estimate the contribution of the high-redshift passive galaxies to the global star formation rate density during their phase of activity, finding that they account for ∼5–10 per cent of the total star formation at 3 < z < 8, despite being only $\sim 0.5{{\ \rm per\ cent}}$ of the total in number. The resulting picture is that early and strong star formation activity, building massive galaxies on short time-scales and followed by a quick and abrupt quenching, is a rare but crucial phenomenon in the early Universe: the evolution of the cosmos must be heavily influenced by the short but powerful activity of these pristine monsters.
In plants, the expression of 14-3-3 genes reacts to various adverse environmental conditions, including cold, high salt, and drought. Although these results suggest that 14-3-3 proteins have the ...potential to regulate plant responses to abiotic stresses, their role in such responses remains poorly understood. Previously, we showed that the RARE COLD INDUCIBLE 1A (RCI1A) gene encodes the 14-3-3 psi isoform. Here, we present genetic and molecular evidence implicating RCI1A in the response to low temperature. Our results demonstrate that RCI1A functions as a negative regulator of constitutive freezing tolerance and cold acclimation in Arabidopsis thaliana by controlling cold-induced gene expression. Interestingly, this control is partially performed through an ethylene (ET)-dependent pathway involving physical interaction with different ACC SYNTHASE (ACS) isoforms and a decreased ACS stability. We show that, consequently, RCI1A restrains ET biosynthesis, contributing to establish adequate levels of this hormone in Arabidopsis under both standard and low-temperature conditions. We further show that these levels are required to promote proper cold-induced gene expression and freezing tolerance before and after cold acclimation. All these data indicate that RCI1A connects the low-temperature response with ET biosynthesis to modulate constitutive freezing tolerance and cold acclimation in Arabidopsis.
ABSTRACT
We present a VLT/X-Shooter spectroscopy of the Lyman continuum (LyC) emitting galaxy Ion2 at z = 3.2121 and compare it to that of the recently discovered strongly lensed LyC emitter at ...z = 2.37, known as the Sunburst arc. Three main results emerge from the X-Shooter spectrum: (a) the Ly α has three distinct peaks with the central one at the systemic redshift, indicating a ionized tunnel through which both Ly α and LyC radiation escape; (b) the large O32 oxygen index (O iii λλ4959, 5007/O ii λλ3727, 3729) of $9.18_{-1.32}^{+1.82}$ is compatible to those measured in local (z ∼0.4) LyC leakers; (c) there are narrow nebular high-ionization metal lines with σv < 20 km s−1, which confirms the presence of young hot, massive stars. The He iiλ1640 appears broad, consistent with a young stellar component including Wolf–Rayet stars. Similarly, the Sunburst LyC emitter shows a triple-peaked Ly α profile and from VLT/MUSE spectroscopy the presence of spectral features arising from young hot and massive stars. The strong lensing magnification, (μ > 20), suggests that this exceptional object is a gravitationally bound star cluster observed at a cosmological distance, with a stellar mass M ≲ 107 M⊙ and an effective radius smaller than 20 pc. Intriguingly, sources like Sunburst but without lensing magnification might appear as Ion2-like galaxies, in which unresolved massive star clusters dominate the ultraviolet emission. This work supports the idea that dense young star clusters can contribute to the ionization of the IGM through holes created by stellar feedback.
Missing [C ii] emission from early galaxies Carniani, S; Ferrara, A; Maiolino, R ...
Monthly notices of the Royal Astronomical Society,
12/2020, Letnik:
499, Številka:
4
Journal Article
Recenzirano
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ABSTRACT
ALMA observations have revealed that C ii 158 μm line emission in high-z galaxies is ≈2–3 × more extended than the UV continuum emission. Here we explore whether surface brightness dimming ...(SBD) of the C ii line is responsible for the reported C ii deficit, and the large $L_{\rm O\, \small {III}}/L_{\rm C\, \small {II}}$ luminosity ratio measured in early galaxies. We first analyse archival ALMA images of nine z > 6 galaxies observed in both C ii and O iii. After performing several uv-tapering experiments to optimize the identification of extended line emission, we detect C ii emission in the whole sample, with an extent systematically larger than the O iii emission. Next, we use interferometric simulations to study the effect of SBD on the line luminosity estimate. About 40 per cent of the extended C ii component might be missed at an angular resolution of 0.8 arcsec, implying that $L_{\rm C\, \small {II}}$ is underestimated by a factor ≈2 in data at low (<7) signal-to-noise ratio. By combining these results, we conclude that $L_{\rm C\, \small {II}}$ of z > 6 galaxies lies, on average, slightly below the local $L_{\rm C\, \small {II}}-\mathrm{ SFR}$ relation (Δz = 6–9 = −0.07 ± 0.3), but within the intrinsic dispersion of the relation. SBD correction also yields $L_{\rm O\, \small {III}}/L_{\rm C\, \small {II}}\lt 10$, i.e. more in line with current hydrodynamical simulations.
Protein synthesis is a fundamental process for life and, as such, plays a crucial role in the adaptation to energy, developmentaland environmental conditions. For these reasons, and despite the ...general conservation of the eukaryotic translational machinery, it is not surprising that organisms with different lifestyles have evolved distinct mechanisms of regulation to adapt translation initiation to their intrinsic growth and development. Plants have clear peculiarities compared with other eukaryotes that have also extended to translation control. This review describes the plant-specific mechanisms for regulation of translation initiation, with a focus on those that modulate the eIF4F complexes, central translational regulatory hubs in all eukaryotes, and highlights the latest discoveries on the signaling pathways that regulate their constituents and activity.
ABSTRACT
We present a Bayesian full-spectral-fitting analysis of 75 massive ($M_* \gt 10^{10.3} \, \mathrm{M_\odot }$) UVJ-selected galaxies at redshifts of 1.0 < z < 1.3, combining extremely deep ...rest-frame ultraviolet spectroscopy from VANDELS with multiwavelength photometry. By the use of a sophisticated physical plus systematic uncertainties model, constructed within the bagpipes code, we place strong constraints on the star-formation histories (SFHs) of individual objects. We first constrain the stellar mass versus stellar age relationship, finding a steep trend towards earlier average formation time with increasing stellar mass (downsizing) of $1.48^{+0.34}_{-0.39}$ Gyr per decade in mass, although this shows signs of flattening at $M_* \gt 10^{11} \, \mathrm{M_\odot }$. We show that this is consistent with other spectroscopic studies from 0 < z < 2. This relationship places strong constraints on the AGN-feedback models used in cosmological simulations. We demonstrate that, although the relationships predicted by simba and illustristng agree well with observations at z = 0.1, they are too shallow at z = 1, predicting an evolution of ≲0.5 Gyr per decade in mass. Secondly, we consider the connections between green-valley, post-starburst, and quiescent galaxies, using our inferred SFH shapes and the distributions of galaxy physical properties on the UVJ diagram. The majority of our lowest-mass galaxies ($M_* \sim 10^{10.5} \, \mathrm{M_\odot }$) are consistent with formation in recent (z < 2), intense starburst events, with time-scales of ≲500 Myr. A second class of objects experience extended star-formation epochs before rapidly quenching, passing through both green-valley and post-starburst phases. The most massive galaxies in our sample are extreme systems: already old by z = 1, they formed at z ∼ 5 and quenched by z = 3. However, we find evidence for their continued evolution through both AGN and rejuvenated star-formation activity.
Dysfunction associated with the aging process positions aging as a leading culprit for development of devastating diseases and mounting health-care costs. Many age-associated conditions for which ...aging increases risk are neurological disorders with no effective treatments, including Alzhei-mer's disease. As the proportion of aged individuals continues to rise in the coming decades, aging-related costs are expected to increase dramatically. Diverse approaches have emerged to meet the clinical need to treat aging and its associated conditions, including those aimed at increasing longevity, slowing the aging process itself, and improving healthspan. An emerging approach takes advantage of molecules circulating in the blood to limit or reverse aspects of aging in various organs throughout the body. Efforts are underway to translate these findings into novel therapeutics that harness the activity of youth-associated molecules present within blood. Here, we discuss the current state of blood-based approaches in this arena. Despite the apparent ease with which blood products might conceivably be applied as treatment paradigms, we propose that challenges nonetheless exist, which may be overcome with mechanistic studies that identify common pathways for targeted therapeutics.
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