The CDK8 kinase module (CKM) is a conserved, dissociable Mediator subcomplex whose component subunits were genetically linked to the RNA polymerase II (RNAPII) C-terminal domain (CTD) and ...individually recognized as transcriptional repressors before Mediator was identified as a pre-eminent complex in eukaryotic transcription regulation. We used macromolecular EM and biochemistry to investigate the subunit organization, structure and Mediator interaction of the Saccharomyces cerevisiae CKM. We found that interaction of the CKM with Mediator's middle module interferes with CTD-dependent RNAPII binding to a previously unknown middle-module CTD-binding site and with the holoenzyme formation process. Taken together, our results reveal the basis for CKM repression, clarify the origin of the connection between CKM subunits and the CTD and suggest that a combination of competitive interactions and conformational changes that facilitate holoenzyme formation underlie the mechanism of transcription regulation by Mediator.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A Disinfection Balancing Act Apicella, Guy; Tipping, Hugh; Kuang, Wayne ...
Water environment & technology,
01/1995, Letnik:
7, Številka:
7
Magazine Article
A study was carried out in New York City to evaluate the use of bromine in wastewater treatment to help reach compliance with both chlorine standards and faecal coliform effluent limits. The effects ...of sodium bromide/sodium hypochlorite on the degree of disinfection and the acute toxicity to mysid shrimp and sheepshead minnow and of chlorination/dechlorination on acute toxicity, were investigated. Studies were carried out at the Tallman Island secondary wastewater treatment works. Faecal coliform counts, total residual chlorine and total residual oxidant were determined. In addition to lowering total residual oxidant levels and maintaining the required levels of disinfection, bromine addition and chlorine-dosing reduction lowered chemical costs.
IMPORTANCE: Optimal management of patients with asymptomatic severe carotid stenosis is uncertain, due to advances in medical care and a lack of contemporary data comparing medical and surgical ...treatment. OBJECTIVE: To estimate stroke outcomes among patients with medically treated asymptomatic severe carotid stenosis who did not undergo surgical intervention. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study that included 3737 adult participants with asymptomatic severe (70%-99%) carotid stenosis diagnosed between 2008 and 2012 and no prior intervention or ipsilateral neurologic event in the prior 6 months. Participants received follow-up through 2019, and all were members of an integrated US regional health system serving 4.5 million members. EXPOSURES: Imaging diagnosis of asymptomatic carotid stenosis of 70% to 99%. MAIN OUTCOMES AND MEASURES: Occurrence of ipsilateral carotid-related acute ischemic stroke. Censoring occurred with death, disenrollment, or ipsilateral intervention. RESULTS: Among 94 822 patients with qualifying imaging studies, 4230 arteries in 3737 (mean age, 73.8 SD 9.5 years; 57.4% male) patients met selection criteria including 2539 arteries in 2314 patients who never received intervention. The mean follow-up in this cohort was 4.1 years (SD 3.6 years). Prior to any intervention, there were 133 ipsilateral strokes with a mean annual stroke rate of 0.9% (95% confidence interval CI, 0.7%-1.2%). The Kaplan-Meier estimate of ipsilateral stroke by 5 years was 4.7% (95% CI, 3.9%-5.7%). CONCLUSIONS AND RELEVANCE: In a community-based cohort of patients with asymptomatic severe carotid stenosis who did not undergo surgical intervention, the estimated rate of ipsilateral carotid-related acute ischemic stroke was 4.7% over 5 years. These findings may inform decision-making regarding surgical and medical treatment for patients with asymptomatic severe carotid artery stenosis.
Background
Liver resection is effective for hepatocellular carcinoma (HCC) exceeding the Milan criteria in selected patients. However, the benefit of anatomical resection (AR) versus non‐anatomical ...resection (NAR) has not been clarified in this patient subgroup. This study aimed to compare outcomes between AR and NAR for HCC exceeding the Milan criteria.
Methods
Data on consecutive patients with HCC exceeding the Milan criteria who underwent liver resection with curative intent over a recent 6‐year interval were extracted from a prospective single‐centre HCC database and examined retrospectively. The postoperative outcomes of patients were compared before and after propensity score matching.
Results
Some 546 patients were included: 264 in the AR and 282 in the NAR group. In the original cohort, the AR group contained more patients with larger tumours, multiple tumours, macroscopic portal vein tumour thrombi, incomplete tumour capsules and microscopic vascular invasion. After propensity score matching, 177 pairs of patients were selected. The baseline data, including liver function and tumour burden, were similar in the matched groups. The 3‐year recurrence‐free survival rate was comparable between the matched NAR and AR groups (36·5 versus 28·5 per cent; P = 0·448). Similar results were observed for 3‐year overall survival (57·5 versus 50·3 per cent; P = 0·385), recurrence patterns and early recurrence rates (57·6 per cent versus 59·9 per cent; P = 0·712).
Conclusion
AR and NAR achieved favourable and similar outcomes for HCC exceeding the Milan criteria in selected patients.
No difference
Biomass burning organic aerosol (BBOA) impacts significantly on climate
directly through scattering and absorbing solar radiation and indirectly
through acting as cloud condensation nuclei. However, ...fundamental parameters
in the simulation of BBOA radiative effects and cloud activities such as
size distribution and refractive index remain poorly parameterized in
models. In this study, biomass burning events with high combustion
efficiency characterized by a high black carbon (BC) to BBOA ratio (0.22 on
average) were frequently observed during autumn in the Pearl River Delta
region, China. An improved absorption Ångström exponent (AAE) ratio
method considering both variations and spectral dependence of black carbon
AAE was proposed to differentiate brown carbon (BrC) absorptions from total
aerosol absorptions. BBOA size distributions, mass scattering and absorption
efficiency were retrieved based on the changes in aerosol number size
distribution, scattering coefficients and derived BrC absorptions that
occurred with BBOA spikes. Geometric mean diameter of BBOA volume size
distribution Dgv depended largely on combustion conditions, ranging
from 245 to 505 nm, and a linear relationship between Dgv and ΔBC/ΔBBOA was achieved. The retrieved real part of the BBOA refractive index
ranges from 1.47 to 1.64, with evidence showing that its variations might
depend largely on combustion efficiency, which is rarely investigated in
existing literature but which however requires further comprehensive investigations.
Retrieved imaginary parts of BBOA refractive index (mi,BBOA) correlated
highly with ΔBC/ΔBBOA (R>0.88) but differ a lot from previous parameterization schemes. The reason behind the inconsistency
might be that single formula parameterizations of mi,BBOA over the
whole BC/BBOA range were used in previous studies which might deviate
substantially for specific BC/BBOA ranges. Thus, a new scheme that
parameterizes wavelength-dependent mi,BBOA was presented, which filled
the gap for field-based BBOA absorptivity parameterizations of
BC/BBOA >0.1. These findings have significant implications for
simulating BBOA climate effects and suggest that linking both BBOA
refractive index and BBOA volume size distributions to BC content might be a
feasible and a good choice for climate models.
Summary
Stimulated emission depletion (STED) microscopy is a useful tool in investigation for super‐resolution realm. By silencing the peripheral fluorophores of the excited spot, leaving only the ...very centre zone vigorous for fluorescence, the effective point spread function (PSF) could be immensely squeezed and subcellular structures, such as organelles, become discernable. Nevertheless, because of the low cross‐section of stimulated emission and the short fluorescence lifetime, the depletion power density has to be extremely higher than the excitation power density and molecules are exposed in high risk of photobleaching. The existence of photobleaching greatly limits the research of STED in achieving higher resolution and more delicate imaging quality, as well as long‐term and dynamic observation. Since the first experimental implementation of STED microscopy, researchers have lift out variety of methods and techniques to alleviate the problem. This paper would present some researches via conventional methods which have been explored and utilised relatively thoroughly, such as fast scanning, time‐gating, two‐photon excitation (TPE), triplet relaxation (T‐Rex) and background suppression. Alternatively, several up‐to‐date techniques, especially adaptive illumination, would also be unveiled for discussion in this paper. The contrast and discussion of these modalities would play an important role in ameliorating the research of STED microscopy.
Lay description
Throughout the centuries, scientists have specific emotional tendency towards optical microscopy in the investigation of microworld. Compared with electron microscopy, optical microscopy embodies certain irreplaceable advantages, due to its noninvasive characteristics and convenience feature. Optical labelling is of vital part of optical discerning, featuring multicolour imaging and high contrast compared with unlabelled imaging. Among extensive labelling materials, fluorophores are outstanding ones. Hence, optical fluorescence microscopy becomes more and more popular in experiments and plays an important role in exploring detailed cellular and even subcellular structures. To the best of our knowledge, the theoretical principle of Abbe theory testifies that an optical imaging cannot discern two spots closer than half of the working wavelength. Taking the minimum visible light (380 nm) for example, the minimal distance of an optical imaging system can separate apart is some sort of 200 nm. Successively, ultraviolet microscope, solid immersion lens and near‐field scanning optical microscopy have been invented to break this limit barrier. However, they have certain shortcomings, such as high photodamage and high complexity, which confine them to specific application scopes. Stimulated emission depletion (STED) microscopy makes a great breakthrough of limit barrier. There are two beams involved in a STED microscope. The first beam, called excitation beam, excites the area of interest to the singlet state; simultaneously, the second beam, called depletion beam with a zero‐intensity centre, forces the peripheral fluorophores to return to the ground state. Then only the very centre area is excited so that the imaging characteristics are alternated and two spots closer than limit barrier could be detectable.
Nonetheless, the depletion intensity has to be extremely higher than the excitation intensity and molecules are exposed in high risk of photobleaching, a phenomenon concerning deterioration of fluorophores. There lift out extensive techniques and methods to combat the photobleaching issue. Fast scanning is an easy‐to‐go methodology to lower the photobleaching effect by decreasing the exposure time‐span of a fluorophore per scan. Time‐gated STED offers an outstanding solution by abandoning short‐lifetime fluorescence emitted by fluorophores that have not been fully exposed by depletion radiance completely so that long‐lifetime fluorophores could be detected. Two‐photon excitation (TPE) combined with STED microscopy lowers the out‐of‐focus influence, reducing the axial bleaching. By modulating the interpulse interval, triplet‐relaxation (T‐Rex) technique successfully avoids the impairment brought by bleaching. Background suppression is to remove the background signals, especially the anti‐Stokes signals caused by stimulated emission radiance. Adaptive illumination aims to solve the problem of uneven power density distribution and calls for illumination light being used only where it is needed.
Many studies have recently been done on understanding the sources
and formation mechanisms of atmospheric aerosols at ground level. However,
vertical profiles and sources of size-resolved particulate ...matter within the
urban boundary layer are still lacking. In this study, vertical distribution
characteristics of size-segregated particles were investigated at three
observation platforms (ground level, 118 m, and 488 m) on the 610 m high
Canton Tower in Guangzhou, China. Size-segregated aerosol samples were
simultaneously collected at the three levels in autumn and winter. Major
aerosol components, including water-soluble ions, organic carbon, and
elemental carbon, were measured. The results showed that daily average
fine-particle concentrations generally decreased with height.
Concentrations of sulfate and ammonium in fine particles displayed shallow
vertical gradients, and nitrate concentrations increased with height in
autumn, while the chemical components showed greater variations in winter
than in autumn. The size distributions of sulfate and ammonium in both
seasons were characterized by a dominant unimodal mode with peaks in the size
range of 0.44–1.0 µm. In autumn, the nitrate size distribution was
bimodal, peaking at 0.44–1.0 and 2.5–10 µm, while in winter
it was unimodal, implying that the formation mechanisms for nitrate
particles were different in the two seasons. Our results suggest that the
majority of the sulfate and nitrate is formed from aqueous-phase reactions,
and we attribute coarse-mode nitrate formation at the measurement site to
the heterogeneous reactions of gaseous nitric acid on existing sea-derived
coarse particles in autumn. Case studies further showed that atmospheric
aqueous-phase and heterogeneous reactions could be important mechanisms for
sulfate and nitrate formation, which, in combination with adverse weather
conditions such as temperature inversion and calm wind, led to haze
formation during autumn and winter in the Pearl River Delta (PRD) region.
The ascending thoracic aorta is designed to withstand biomechanical forces from pulsatile blood. Thoracic aortic aneurysms and acute aortic dissections (TAADs) occur as a result of genetically ...triggered defects in aortic structure and a dysfunctional response to these forces. Here, we describe mutations in the forkhead transcription factor FOXE3 that predispose mutation-bearing individuals to TAAD. We performed exome sequencing of a large family with multiple members with TAADs and identified a rare variant in FOXE3 with an altered amino acid in the DNA-binding domain (p.Asp153His) that segregated with disease in this family. Additional pathogenic FOXE3 variants were identified in unrelated TAAD families. In mice, Foxe3 deficiency reduced smooth muscle cell (SMC) density and impaired SMC differentiation in the ascending aorta. Foxe3 expression was induced in aortic SMCs after transverse aortic constriction, and Foxe3 deficiency increased SMC apoptosis and ascending aortic rupture with increased aortic pressure. These phenotypes were rescued by inhibiting p53 activity, either by administration of a p53 inhibitor (pifithrin-α), or by crossing Foxe3-/- mice with p53-/- mice. Our data demonstrate that FOXE3 mutations lead to a reduced number of aortic SMCs during development and increased SMC apoptosis in the ascending aorta in response to increased biomechanical forces, thus defining an additional molecular pathway that leads to familial thoracic aortic disease.
Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent antitumor effects in B-cell malignancies including acute lymphoblastic leukemia (ALL), but antigen loss remains the major cause ...of treatment failure. To mitigate antigen escape and potentially improve the durability of remission, we developed a dual-targeting approach using an optimized, bispecific CAR construct that targets both CD19 and BAFF-R. CD19/BAFF-R dual CAR T cells exhibited antigen-specific cytokine release, degranulation, and cytotoxicity against both CD19-/- and BAFF-R-/- variant human ALL cells in vitro. Immunodeficient mice engrafted with mixed CD19-/- and BAFF-R-/- variant ALL cells and treated with a single dose of CD19/BAFF-R dual CAR T cells experienced complete eradication of both CD19-/- and BAFF-R-/- ALL variants, whereas mice treated with monospecific CD19 or BAFF-R CAR T cells succumbed to outgrowths of CD19-/BAFF-R+ or CD19+/BAFF-R- tumors, respectively. Further, CD19/BAFF-R dual CAR T cells showed prolonged in vivo persistence, raising the possibility that these cells may have the potential to promote durable remissions. Together, our data support clinical translation of BAFF-R/CD19 dual CAR T cells to treat ALL.
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