ABSTRACT
Recent studies show that a universal relation between black hole (BH) growth and stellar mass (M⋆) or star formation rate (SFR) is an oversimplification of BH–galaxy coevolution, and that ...morphological and structural properties of host galaxies must also be considered. Particularly, a possible connection between BH growth and host-galaxy compactness was identified among star-forming (SF) galaxies. Utilizing ≈6300 massive galaxies with I814W < 24 at z < 1.2 in the Cosmic Evolution Survey (COSMOS) field, we perform systematic partial correlation analyses to investigate how sample-averaged BH accretion rate ($\rm \overline{BHAR}$) depends on host-galaxy compactness among SF galaxies, when controlling for morphology and M⋆ (or SFR). The projected central surface mass density within 1 kpc, Σ1, is utilized to represent host-galaxy compactness in our study. We find that the $\rm \overline{BHAR}$–Σ1 relation is stronger than either the $\rm \overline{BHAR}$–M⋆ or $\rm \overline{BHAR}$–SFR relation among SF galaxies, and this $\rm \overline{BHAR}$–Σ1 relation applies to both bulge-dominated galaxies and galaxies that are not dominated by bulges. This $\rm \overline{BHAR}$–Σ1 relation among SF galaxies suggests a link between BH growth and the central gas density of host galaxies on the kpc scale, which may further imply a common origin of the gas in the vicinity of the BH and in the central ∼kpc of the galaxy. This $\rm \overline{BHAR}$–Σ1 relation can also be interpreted as the relation between BH growth and the central velocity dispersion of host galaxies at a given gas content (i.e. gas mass fraction), indicating the role of the host-galaxy potential well in regulating accretion on to the BH.
ABSTRACT
Observations in the local universe show a tight correlation between the masses of supermassive black holes (SMBHs; MBH) and host-galaxy bulges (Mbulge), suggesting a strong connection ...between SMBH and bulge growth. However, direct evidence for such a connection in the distant universe remains elusive. We have studied sample-averaged SMBH accretion rate ($\overline{\rm BHAR}$) for bulge-dominated galaxies at z = 0.5–3. While previous observations found $\overline{\rm BHAR}$ is strongly related to host-galaxy stellar mass (M⋆) for the overall galaxy population, our analyses show that, for the bulge-dominated population, $\overline{\rm BHAR}$ is mainly related to SFR rather than M⋆. This ${\overline{\rm BHAR}}$–SFR relation is highly significant, e.g. 9.0σ (Pearson statistic) at z = 0.5–1.5. Such a $\overline{\rm BHAR}$–SFR connection does not exist among our comparison sample of galaxies that are not bulge dominated, for which M⋆ appears to be the main determinant of SMBH accretion. This difference between the bulge-dominated and comparison samples indicates that SMBHs only coevolve with bulges rather than the entire galaxies, explaining the tightness of the local MBH−Mbulge correlation. Our best-fitting ${\overline{\rm BHAR}}$–SFR relation for the bulge-dominated sample is ${\log \overline{\rm BHAR}= \log \mathrm{SFR} - (2.48\pm 0.05)}$ (solar units). The best-fitting $\overline{\rm BHAR}/\mathrm{SFR}$ ratio (10−2.48) for bulge-dominated galaxies is similar to the observed MBH/Mbulge values in the local universe. Our results reveal that SMBH and bulge growth are in lockstep, and thus non-causal scenarios of merger averaging are unlikely the origin of the MBH−Mbulge correlation. This lockstep growth also predicts that the MBH−Mbulge relation should not have strong redshift dependence.
How might fully saturated benzene polymers of composition (CH)6 n form under high pressure? In the first approach to answering this question, we examine the stepwise increase in saturation of a ...one-dimensional stack of benzene molecules by enumerating the partially saturated polymer intermediates, subject to constraints of unit cell size and energy. Defining the number of four-coordinate carbon atoms per benzene formula unit as the degree of saturation, a set of isomers for degree-two and degree-four polymers can be generated by either thinking of the propagation of partially saturated building blocks or by considering a sequence of cycloadditions. There is also one 4 + 2 reaction sequence that jumps directly from a benzene stack to a degree-four polymer. The set of degree-two polymers provides several useful signposts toward achieving full saturation: chiral versus achiral building blocks, certain forms of conformational freedom, and also dead ends to further saturation. These insights allow us to generate a larger set of degree-four polymers and enumerate the many pathways that lead from benzene stacks to completely saturated carbon nanothreads.
Background and purpose
Elevated plasma total homocysteine level (tHcy) is associated with increased risk of dementia via increased white matter changes or reduction in cortical volume. Whether tHcy ...has an independent impact on regional perfusion and if it can predict a more rapid cognitive decline in mild Alzheimer dementia (AD) warrants investigation.
Methods
Eighty AD patients with a clinical dementia rating of 1 were enrolled. Their Cognitive Ability Screening Instrument (CASI) scores on enrolment and after 1 year of follow‐up as well as their perfusion index (PI) from single photon emission computed tomography upon enrolment were analyzed.
Results
In cross‐sectional analysis, elevated tHcy was associated with lower frontal PI independent of cerebrovascular risk factors (β = −0.35, P = 0.009). The CASI scores correlated with temporo‐parietal PI (Pearson r range 0.3–0.39, P < 0.01) but not with tHcy or frontal PI. By longitudinal analysis, only tHcy level was related to a more rapid cognitive decline (odds ratio for executive function score 1.82; odds ratio for total CASI score 1.74).
Conclusions
Cognitive performance in mild AD can be reflected by hypo‐perfusion of the temporo‐parietal region while frontal hypo‐perfusion may be mediated by tHcy. tHcy level is an independent risk factor for rapid cognitive decline, especially in the executive function.
Prohibitin, which can inhibit oxidative stress and mitochondrial dysfunction, has been shown to have significant anti-inflammatory activities. Here, we investigate the effects of altering prohibitin ...levels in affected tissues in the interleukin-10 knockout (IL-10KO) mouse model with intestinal fibrosis. The aim of this study is to investigate the effects of IL-10 on prohibitin and the role of prohibitin in intestinal fibrosis of murine colitis. After the mice were treated with IL-10, prohibitin expression and localization were evaluated in IL-10KO and wild-type (WT, 129/SvEv) mice. The colon tissue was then investigated and the potential pathogenic molecular mechanisms were further studied. Fluorescence-based quantitative polymerase chain reaction (FQ-PCR) and immunohistochemistry assays revealed a significant upregulation of prohibitin with IL-10 treatment. Furthermore, IL-10 decreases inflammatory cytokines and TGF-β1 in the IL-10KO model of Crohn’s disease and demonstrates a promising trend in decreasing tissue fibrosis. In conclusion, we hypothesize that IL-10 treatment is associated with increased prohibitin and would decrease inflammation and fibrosis in an animal model of Crohn’s disease. Interestingly, prohibitin may be a potential target for intestinal fibrosis associated with inflammatory bowel disease (IBD).
ABSTRACT
Possible connections between central black hole (BH) growth and host-galaxy compactness have been found observationally, which may provide insight into BH–galaxy coevolution: compact ...galaxies might have large amounts of gas in their centres due to their high mass-to-size ratios, and simulations predict that high central gas density can boost BH accretion. However, it is not yet clear if BH growth is fundamentally related to the compactness of the host galaxy, due to observational degeneracies between compactness, stellar mass (M⋆) and star formation rate (SFR). To break these degeneracies, we carry out systematic partial-correlation studies to investigate the dependence of sample-averaged BH accretion rate ($\rm \overline{BHAR}$) on the compactness of host galaxies, represented by the surface-mass density, Σe, or the projected central surface-mass density within 1 kpc, Σ1. We utilize 8842 galaxies with H < 24.5 in the five CANDELS fields at z = 0.5–3. We find that $\rm \overline{BHAR}$ does not significantly depend on compactness when controlling for SFR or M⋆ among bulge-dominated galaxies and galaxies that are not dominated by bulges, respectively. However, when testing is confined to star-forming galaxies at z = 0.5–1.5, we find that the $\rm \overline{BHAR}$–Σ1 relation is not simply a secondary manifestation of a primary $\rm \overline{BHAR}$–M⋆ relation, which may indicate a link between BH growth and the gas density within the central 1 kpc of galaxies.
Abstract
The heat carriers responsible for the unexpectedly large thermal Hall conductivity of the cuprate Mott insulator La
2
CuO
4
were recently shown to be phonons. However, the mechanism by which ...phonons in cuprates acquire chirality in a magnetic field is still unknown. Here, we report a similar thermal Hall conductivity in two cuprate Mott insulators with significantly different crystal structures and magnetic orders – Nd
2
CuO
4
and Sr
2
CuO
2
Cl
2
– and show that two potential mechanisms can be excluded – the scattering of phonons by rare-earth impurities and by structural domains. Our comparative study further reveals that orthorhombicity, apical oxygens, the tilting of oxygen octahedra and the canting of spins out of the CuO
2
planes are not essential to the mechanism of chirality. Our findings point to a chiral mechanism coming from a coupling of acoustic phonons to the intrinsic excitations of the CuO
2
planes.
Objectives
To elucidate the relationship between various sleep-wake-related indicators and nutritional status.
Design
Cross-sectional study.
Setting
Community-based survey between 2017 and 2022 in ...Yilan City, Taiwan.
Participants
1,905 community-dwelling older adults aged ≥65 years.
Measurements
Nutritional status was evaluated using the Mini Nutritional Assessment, and participants were classified into normal nutritional status and undernutrition groups. Regarding sleep-wake-related indicators, specific items or component scores of the Pittsburgh Sleep Quality Index were used to assess sleep-wake schedule, subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, presence of sleep disturbances, hypnotic use, and dysfunction in maintaining enthusiasm. The 5-item Athens Insomnia Scale and the Epworth Sleepiness Scale were used to evaluate insomnia and excessive daytime sleepiness, respectively.
Results
Of the 1,905 participants, the mean age was 75.6±7.1, with 52.2% being ≥75 years old, 58.9% were women, and 11.4% had undernutrition. After controlling for covariates, short sleepers were less likely to have undernutrition (OR: 0.63; 95% CI: 0.41–0.97); in contrast, long sleepers were more likely to exhibit undernutrition (OR: 1.52; 95% CI: 1.06–2.17). In addition, poor habitual sleep efficiency (OR:1.69; 95% CI:1.15–2.50), taking hypnotics in the past month (OR: 1.58; 95% CI: 1.12–2.24), and dysfunction in maintaining enthusiasm (OR: 1.93; 95% CI: 1.24–2.99) were associated with increased risk of undernutrition.
Conclusions
Among older adults, various sleep-wake-related indicators differed in their relationships with nutritional status. Specific sleep-wake disturbances may indicate undernutrition in this population.
Results from microbiome studies on oral cancer have been inconsistent, probably because they focused on compositional analysis, which does not account for functional redundancy among oral bacteria. ...Based on functional prediction, a recent study revealed enrichment of inflammatory bacterial attributes in oral squamous cell carcinoma (OSCC). Given the high relevance of this finding to carcinogenesis, we aimed here to corroborate them in a case-control study involving 25 OSCC cases and 27 fibroepithelial polyp (FEP) controls from Sri Lanka. DNA extracted from fresh biopsies was sequenced for the V1 to V3 region with Illumina’s 2 × 300–bp chemistry. High-quality nonchimeric merged reads were classified to the species level with a prioritized BLASTN-based algorithm. Downstream compositional analysis was performed with QIIME (Quantitative Insights into Microbial Ecology) and linear discriminant analysis effect size, while PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) was utilized for bacteriome functional prediction. The OSCC tissues tended to have lower species richness and diversity. Genera Capnocytophaga, Pseudomonas, and Atopobium were overrepresented in OSCC, while Lautropia, Staphylococcus, and Propionibacterium were the most abundant in FEP. At the species level, Campylobacter concisus, Prevotella salivae, Prevotella loeschii, and Fusobacterium oral taxon 204 were enriched in OSCC, while Streptococcus mitis, Streptococcus oral taxon 070, Lautropia mirabilis, and Rothia dentocariosa among others were more abundant in FEP. Functionally, proinflammatory bacterial attributes, including lipopolysaccharide biosynthesis and peptidases, were enriched in the OSCC tissues. Thus, while the results in terms of species composition significantly differed from the original study, they were consistent at the functional level, substantiating evidence for the inflammatory nature of the bacteriome associated with OSCC.
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