Abstract
Quasar feedback may regulate the growth of supermassive black holes, quench coeval star formation, and impact galaxy morphology and the circumgalactic medium. However, direct evidence for ...quasar feedback in action at the epoch of peak black hole accretion at
z
≈ 2 remains elusive. A good case in point is the
z
= 1.6 quasar WISEA J100211.29+013706.7 (XID 2028), where past analyses of the same ground-based data have come to different conclusions. Here, we revisit this object with the integral-field unit of the Near Infrared Spectrograph on board the JWST as part of Early Release Science program Q3D. The excellent angular resolution and sensitivity of the JWST data reveal new morphological and kinematic substructures in the outflowing gas plume. An analysis of the emission-line ratios indicates that photoionization by the central quasar dominates the ionization state of the gas with no obvious sign for a major contribution from hot young stars anywhere in the host galaxy. The rest-frame near-UV emission aligned along the wide-angle cone of outflowing gas is interpreted as a scattering cone. The outflow has cleared a channel in the dusty host galaxy, through which some of the quasar ionizing radiation is able to escape and heat the surrounding interstellar and circumgalactic media. Although the warm ionized outflow is not powerful enough to impact the host galaxy via mechanical feedback, radiative feedback by the active galactic nucleus, aided by the outflow, may help to explain the unusually small molecular gas mass fraction in the galaxy host.
The synthesis and reactivity of a silyliumylidene cation stabilized by an amidinate ligand and 4‐dimethylaminopyridine (DMAP) are described. The reaction of the amidinate silicon(I) dimer LSi:2 (1; ...L=PhC(NtBu)2) with one equivalent of N‐trimethylsilyl‐4‐dimethylaminopyridinium triflate 4‐NMe2C5H4NSiMe3OTf and two equivalents of DMAP in THF afforded LSi(DMAP)OTf (2). The ambiphilic character of 2 is demonstrated from its reactivity. Treatment of 2 with 1 in THF afforded the disilylenylsilylium triflate L′2(L)SiOTf (3; L′=LSi:) with the displacement of DMAP. The reaction of 2 with K{HB(iBu)3} and elemental sulfur in THF afforded the silylsilylene LSiSi(H){(NtBu)2C(H)Ph} (4) and the base‐stabilized silanethionium triflate LSi(S)DMAPOTf (5), respectively. Compounds 2, 3, and 5 have been characterized by X‐ray crystallography.
1 becomes 2: The singlet silyliumylidene cation 2, which is stabilized by both an amidinate ligand and 4‐dimethylaminopyridine (DMAP), can be synthesized by the reaction of the amidinate SiI dimer 1 with N‐trimethylsilyl‐4‐dimethylaminopyridinium triflate and DMAP (see scheme). The ambiphilic character of 2 can be demonstrated by its reactivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Dengue (DENV) and Zika (ZIKV) viruses are clinically important members of the Flaviviridae family with an 11 kb positive strand RNA genome that folds to enable virus function. Here, we perform ...structure and interaction mapping on four DENV and ZIKV strains inside virions and in infected cells. Comparative analysis of SHAPE reactivities across serotypes nominates potentially functional regions that are highly structured, conserved, and contain low synonymous mutation rates. Interaction mapping by SPLASH identifies many pair-wise interactions, 40% of which form alternative structures, suggesting extensive structural heterogeneity. Analysis of shared interactions between serotypes reveals a conserved macro-organization whereby interactions can be preserved at physical locations beyond sequence identities. We further observe that longer-range interactions are preferentially disrupted inside cells, and show the importance of new interactions in virus fitness. These findings deepen our understanding of Flavivirus genome organization and serve as a resource for designing therapeutics in targeting RNA viruses.
Background
This study aimed to review studies that identified patterns of longitudinal HbA1c trends in patients with diabetes and to summarize factors and outcomes associated with distinct trajectory ...patterns.
Methods
PubMed and Web of Science were systematically searched for studies examining HbA1c trends among patients with diabetes from database inception through September 2017. Articles were included if they met the following inclusion criteria: (a) longitudinal study of subjects with diabetes only, (b) use of serial measurements of HbA1c, and (c) analysis of the trend of HbA1c using group‐based trajectory approaches.
Results
Twenty studies were included, 11 on type 1 diabetes and 9 on type 2 diabetes. These studies identified 2 to 6 HbA1c trajectory patterns. The most commonly identified patterns included stable HbA1c around 7.0% and at levels between 8.0% and 9.9%, which usually captured the HbA1c pattern among the majority of subjects in the study population. Unstable patterns identified included increasing HbA1c trend, decreasing HbA1c trend, and non‐linear patterns. These patterns were associated with differential risk of disease outcomes, over and beyond single‐point HbA1c measures. Age, gender, ethnicity, diabetes duration, disease management frequency, cardiovascular risk factors, insulin treatment, family environment, and psychosocial factors were the most frequently reported factors associated with membership of specific HbA1c pattern groups.
Conclusion
Common patterns of longitudinal HbA1c trends were identified despite heterogeneity among the studies. A better understanding of what underlies these different patterns may provide opportunities to tailor therapies and care for these patients to reduce adverse outcomes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We aimed to determine the 6-year incidence and risk factors of age-related macular degeneration (AMD) in first and second generations of Singaporean Indians. Baseline examination was conducted in ...2007-9 and 6-year propsective follow-up examination of this Indian population in 2013-5. All participants underwent interviews with questionnaires and comprehensive medical and eye examinations. Incidence was age-standardized to Singaporean 2010 census. Risk factors associated with AMD incidence were assessed and compared between first and second generations of immigrants. Among 2200 persons who participated in the follow-up examination (75.5% response rate), gradable fundus photographs were available in 2105. The 6-year age-standardized incidences of early and late AMD were 5.26% and 0.51% respectively. Incident early AMD was associated with cardiovascular disease history (HR 1.59, 95% CI 1.04-2.45), underweight body mass index (BMI) (HR 3.12, 95% CI 1.37-7.14) (BMI of <18.5 vs 18.51-25 kg/m2), heavy alcohol drinking (HR 3.14 95% CI 1.25-7.89) and ARMS2 rs3750847 homozygous genetic loci carrier (HR 2.52, 95% CI 1.59-3.99). We found a relatively low incidence of early AMD in this Singaporean Indian population compared to Caucasian populations. Both first and second-generation Indian immigrants have similar incidence and risk factor patterns for early AMD.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Identifying host factors is key to understanding RNA virus pathogenicity. Besides proteins, RNAs can interact with virus genomes to impact replication.
Here, we use proximity ligation sequencing to ...identify virus-host RNA interactions for four strains of Zika virus (ZIKV) and one strain of dengue virus (DENV-1) in human cells. We find hundreds of coding and non-coding RNAs that bind to DENV and ZIKV viruses. Host RNAs tend to bind to single-stranded regions along the virus genomes according to hybridization energetics. Compared to SARS-CoV-2 interactors, ZIKV-interacting host RNAs tend to be downregulated upon virus infection. Knockdown of several short non-coding RNAs, including miR19a-3p, and 7SK RNA results in a decrease in viral replication, suggesting that they act as virus-permissive factors. In addition, the 3'UTR of DYNLT1 mRNA acts as a virus-restrictive factor by binding to the conserved dumbbell region on DENV and ZIKV 3'UTR to decrease virus replication. We also identify a conserved set of host RNAs that interacts with DENV, ZIKV, and SARS-CoV-2, suggesting that these RNAs are broadly important for RNA virus infection.
This study demonstrates that host RNAs can impact virus replication in permissive and restrictive ways, expanding our understanding of host factors and RNA-based gene regulation during viral pathogenesis.
Abstract
Massive galaxies formed most actively at redshifts
z
= 1–3 during the period known as “cosmic noon.” Here we present an emission-line study of the extremely red quasar ...SDSSJ165202.64+172852.3’s host galaxy at
z
= 2.94, based on observations with the Near Infrared Spectrograph integral field unit on board JWST. We use standard emission-line diagnostic ratios to map the sources of gas ionization across the host and a swarm of companion galaxies. The quasar dominates the photoionization, but we also discover shock-excited regions orthogonal to the ionization cone and the quasar-driven outflow. These shocks could be merger-induced or—more likely, given the presence of a powerful galactic-scale quasar outflow—these are signatures of wide-angle outflows that can reach parts of the galaxy that are not directly illuminated by the quasar. Finally, the kinematically narrow emission associated with the host galaxy presents as a collection of 1 kpc–scale clumps forming stars at a rate of at least 200
M
⊙
yr
−1
. The interstellar medium within these clumps shows high electron densities, reaching up to 3000 cm
−3
, with metallicities ranging from half to a third solar with a positive metallicity gradient, and
V
-band extinctions up to 3 mag. The star formation conditions are far more extreme in these regions than in local star-forming galaxies but consistent with those of massive galaxies at cosmic noon. The JWST observations simultaneously reveal an archetypal rapidly forming massive galaxy undergoing a merger, a clumpy starburst, an episode of obscured near-Eddington quasar activity, and an extremely powerful quasar outflow.
Abstract
Quasar-driven galactic outflows are a major driver of the evolution of massive galaxies. We report observations of a powerful galactic-scale outflow in a
z
= 3 extremely red and ...intrinsically luminous (
L
bol
≃ 5 × 10
47
erg s
−1
) quasar SDSSJ1652 + 1728 with the Near-infrared Spectrograph on board JWST. We analyze the kinematics of rest-frame optical emission lines and identify the quasar-driven outflow extending out to ∼10 kpc from the quasar with a velocity offset of (
v
r
= ± 500 km s
−1
) and high velocity dispersion (FWHM = 700–2400 km s
−1
). Due to JWST’s unprecedented surface brightness sensitivity in the near-infrared, we unambiguously show that the powerful high velocity outflow in an extremely red quasar encompasses a large swath of the host galaxy’s interstellar medium. Using the kinematics and dynamics of optical emission lines, we estimate the mass outflow rate—in the warm ionized phase alone—to be at least 2300 ± 1400
M
⊙
yr
−1
. We measure a momentum flux ratio between the outflow and the quasar accretion disk of ∼1 on a kpc scale, indicating that the outflow was likely driven in a relatively high (>10
23
cm
−2
) column density environment through radiation pressure on dust grains. We find a coupling efficiency between the bolometric luminosity of the quasar and the outflow of 0.1%, matching the theoretical prediction of the minimum coupling efficiency necessary for negative quasar feedback. The outflow has sufficient energetics to drive the observed turbulence seen in shocked regions of the quasar host galaxy, which are likely directly responsible for prolonging the time that it takes for gas to cool efficiently.
The synthesis and characterization of novel cis‐1,2‐disilylenylethene cis‐LSi{C(Ph)C(H)}SiL (2; L=PhC(NtBu)2) and a singlet delocalized biradicaloid LSi(μ2‐C2Ph2)2SiL (3) are described. Compound 2 ...was prepared by the reaction of {PhC(NtBu)2}Si:2 (1) with one equivalent of PhCCH in toluene. Compound 3 was synthesized by the reaction of 1 with two equivalents of PhCCPh in toluene. The results suggest that the reaction proceeds through an LSi{C(Ph)C(Ph)}SiL intermediate, which then reacts with another molecule of PhCCPh to form 3. Compounds 2 and 3 have been characterized by X‐ray crystallography and NMR spectroscopy. X‐ray crystallography and DFT calculations of 3 show that the singlet biradicals are stabilized by the amidinate ligand and the delocalization within the “Si(μ2‐C2Ph2)2Si” six‐membered ring.
The new radicals: A novel amidinate‐stabilized singlet delocalized biradicaloid LSi(μ2‐C2Ph2)2SiL (L=PhC(NtBu)2) has been synthesized successfully by the reaction of {PhC(NtBu)2}Si2 with diphenylacetylene. X‐ray crystallography and DFT calculations show that the diradicals are stabilized by the amidinate ligand and the delocalization within the Si(μ2‐C2Ph2)2Si six‐membered ring (see figure).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The syntheses of a zwitterionic base‐stabilized digermadistannacyclobutadiene and tetragermacyclobutadiene supported by amidinates and low‐valent germanium amidinate substituents are described. The ...reaction of the amidinate GeI dimer, LGe:2 (1, L=PhC(NtBu)2), with two equivalents of the amidinate tin(II) chloride, LSnCl (2), and KC8 in tetrahydrofuran (THF) at room temperature afforded a mixture of the zwitterionic base‐stabilized digermadistannacyclobutadiene, L2Ge2Sn2L′2 (3; L′=LGe:), and the bis(amidinate) tin(II) compound, L2Sn: (4). Compound 3 can also be prepared by the reaction of 1 with LArSnCl (5, LAr=tBuC(NAr)2, Ar=2,6‐iPr2C6H3) in THF at room temperature. Moreover, the reaction of 1 with the “onio‐substituent transfer” reagent 4‐NMe2‐C5H4NSiMe3OTf (8) in THF and 4‐(N,N‐dimethylamino)pyridine (DMAP) at room temperature afforded a mixture of the zwitterionic base‐stabilized tetragermacyclobutadiene, L4Ge6 (9), the amidinium triflate, PhC(NHtBu)2OTf (10), and Me3SiSiMe3 (11). X‐ray structural data and theoretical studies show conclusively that compounds 3 and 9 have a planar and rhombic charge‐separated structure. They are also nonaromatic.
Heavy elements: Zwitterionic base‐stabilized digermadistannacyclobutadiene (1) and tetragermacyclobutadiene (2) were synthesized by simple procedures (see scheme). X‐ray structural data and theoretical studies show that these compounds have a planar and rhombic charge‐separated structure. They are also nonaromatic.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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