256 research outputs found
Decentralized Base-Graph Routing for the Quantum Internet
Quantum repeater networks are a fundamental of any future quantum Internet
and long-distance quantum communications. The entangled quantum nodes can
communicate through several different levels of entanglement, leading to a
heterogeneous, multi-level network structure. The level of entanglement between
the quantum nodes determines the hop distance and the probability of the
existence of an entangled link in the network. Here, we define a decentralized
routing for entangled quantum networks. The proposed method allows an efficient
routing to find the shortest paths in entangled quantum networks by using only
local knowledge of the quantum nodes. We give bounds on the maximum value of
the total number of entangled links of a path. The proposed scheme can be
directly applied in practical quantum communications and quantum networking
scenarios.Comment: 13 pages, Journal-ref: Phys. Rev.
Association of Receiving Multiple, Concurrent Fracture-Associated Drugs With Hip Fracture Risk
Importance: Many prescription drugs increase fracture risk, which raises concern for patients receiving 2 or more such drugs concurrently. Logic suggests that risk will increase with each additional drug, but the risk of taking multiple fracture-associated drugs (FADs) is unknown.
Objective: To estimate hip fracture risk associated with concurrent exposure to multiple FADs.
Design, Setting, and Participants: This cohort study used a 20% random sample of Medicare fee-for-service administrative data for age-eligible Medicare beneficiaries from 2004 to 2014. Sex-stratified Cox regression models estimated hip fracture risk associated with current receipt of 1, 2, or 3 or more of 21 FADs and, separately, risk associated with each FAD and 2-way FAD combination vs no FADs. Models included sociodemographic characteristics, comorbidities, and use of non-FAD medications. Analyses began in November 2018 and were completed April 2019.
Exposure: Receipt of prescription FADs.
Main Outcomes and Measures: Hip fracture hospitalization.
Results: A total of 11.3 million person-years were observed, reflecting 2,646,255 individuals (mean [SD] age, 77.2 [7.3] years, 1,615,613 [61.1%] women, 2,136,585 [80.7%] white, and 219 579 [8.3%] black). Overall, 2,827,284 person-years (25.1%) involved receipt of 1 FAD; 1,322,296 (11.7%), 2 FADs; and 954,506 (8.5%), 3 or more FADs. In fully adjusted, sex-stratified models, an increase in hip fracture risk among women was associated with the receipt of 1, 2, or 3 or more FADs (1 FAD: hazard ratio [HR], 2.04; 95% CI, 1.99-2.11; P\u3c.001; 2 FADs: HR, 2.86; 95% CI, 2.77-2.95; P\u3c.001; ≥3 FADs: HR, 4.50; 95% CI, 4.36-4.65; P\u3c.001). Relative risks for men were slightly higher (1 FAD: HR, 2.23; 95% CI, 2.11-2.36; P\u3c.001; 2 FADs: HR, 3.40; 95% CI, 3.20-3.61; P\u3c.001; ≥3 FADs: HR, 5.18; 95% CI, 4.87-5.52; P\u3c.001). Among women, 2 individual FADs were associated with HRs greater than 3.00; 80 pairs of FADs exceeded this threshold. Common, risky pairs among women included sedative hypnotics plus opioids (HR, 4.90; 95% CI, 3.98-6.02; P\u3c.001), serotonin reuptake inhibitors plus benzodiazepines (HR, 4.50; 95% CI, 3.76-5.38; P\u3c.001), and proton pump inhibitors plus opioids (HR, 4.00; 95% CI, 3.56-4.49; P\u3c.001). Receipt of 1, 2, or 3 or more non-FADs was associated with a small, significant reduction in fracture risk compared with receipt of no non-FADs among women (1 non-FAD: HR, 0.93; 95% CI, 0.90-0.96; P\u3c.001; 2 non-FADs: HR, 0.84; 95% CI, 0.81-0.87; P\u3c.001; ≥3 non-FADs: HR, 0.74; 95% CI, 0.72-0.77; P\u3c.001).
Conclusions and Relevance: Among older adults, FADs are commonly used and commonly combined. In this cohort study, the addition of a second and third FAD was associated with a steep increase in fracture risk. Many risky pairs of FADs included potentially avoidable drugs (eg, sedatives and opioids). If confirmed, these findings suggest that fracture risk could be reduced through tighter adherence to long-established prescribing guidelines and recommendations
IgG and IgM Autoantibody Differences in Discoid and Systemic Lupus Patients
Systemic lupus erythematosus (SLE) patients with discoid lupus erythematosus (DLE) were reported to have milder disease. To test this observation, we used sandwich arrays containing 98 autoantigens to compare autoantibody profiles of SLE subjects without DLE (DLE-SLE+) (N=9), SLE subjects with DLE (DLE+SLE+) (N=10), DLE subjects without SLE (DLE+SLE-) (N=11), and healthy controls (N=11). We validated differentially expressed autoantibodies using immunoassays in DLE-SLE+ (N=18), DLE+SLE+ (N=17), DLE+SLE- (N=23), and healthy subjects (N=22). Arrays showed 15 IgG autoantibodies (10 against nuclear antigens) and 4 IgM autoantibodies that were differentially expressed (q-value<0.05). DLE-SLE+ subjects had higher IgG autoantibodies against double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), double-stranded RNA (dsRNA), histone H2A and H2B, and SS-A (52kDa) compared with all other groups including DLE+SLE+ subjects (P<0.05). Immunoassays measuring anti-dsDNA, -ssDNA, and -SS-A (52kDa) IgG autoantibodies showed similar trends (P<0.05). Healthy and DLE+SLE- subjects expressed higher IgM autoantibodies against alpha beta crystallin, lipopolysaccharide, heat-shock cognate 70, and desmoglein-3 compared with DLE+SLE+ and DLE-SLE+ subjects. IgG:IgM ratios of autoantibodies against nuclear antigens progressively rose from healthy to DLE-SLE+ subjects. In conclusion, lower IgG autoantibodies against nuclear antigens in DLE+SLE+ versus DLE-SLE+ subjects suggest that DLE indicates lower disease severity. Higher IgM autoantibodies against selected antigens in healthy and DLE+SLE- subjects may be nonpathogenic
Overexpression of the Aspergillus nidulans histone 4 acetyltransferase EsaA increases activation of secondary metabolite production
This is the peer reviewed version of the following article: Soukup, A. A., Chiang, Y.-M., Bok, J. W., Reyes-Dominguez, Y., Oakley, B. R., Wang, C. C. C., Strauss, J. and Keller, N. P. (2012), Overexpression of the Aspergillus nidulans histone 4 acetyltransferase EsaA increases activation of secondary metabolite production. Molecular Microbiology, 86: 314–330. doi:10.1111/j.1365-2958.2012.08195.x, which has been published in final form at http://doi.org/10.1111/j.1365-2958.2012.08195.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Regulation of secondary metabolite (SM) gene clusters in Aspergillus nidulans has been shown to occur through cluster specific transcription factors or through global regulators of chromatin structure such as histone methyltransferases, histone deacetylases, or the putative methyltransferase LaeA. A multi-copy suppressor screen for genes capable of returning SM production to the SM deficient ΔlaeA mutant resulted in identification of the essential histone acetyltransferase EsaA, able to complement an esa1 deletion in Saccharomyces cereviseae. Here we report that EsaA plays a novel role in SM cluster activation through histone 4 lysine 12 (H4K12) acetylation in four examined SM gene clusters (sterigmatocystin, penicillin, terrequinone, and orsellinic acid), in contrast to no increase in H4K12 acetylation of the housekeeping tubA promoter. This augmented SM cluster acetylation requires LaeA for full effect and correlates with both increased transcript levels and metabolite production relative to wild type. H4K12 levels may thus represent a unique indicator of relative production potential, notably of SMs
Molecular genetic analysis of the orsellinic acid/F9775 gene cluster of Aspergillus nidulans†,‡
F-9775A and F-9775B are cathepsin K inhibitors that arise from a chromatin remodelling deletant strain of Aspergillus nidulans. A polyketide synthase gene has been determined to be responsible for their formation and for the simpler, archetypical polyketide orsellinic acid. We have discovered simple culture conditions that result in the production of the three compounds, and this facilitates analysis of the genes responsible for their synthesis. We have now analysed the F9775/orsellinic acid gene cluster using a set of targeted deletions. We find that the polyketide synthase alone is required for orsellinic acid biosynthesis and only two additional genes in the cluster are required for F9775 A and B synthesis. Our deletions also yielded the bioactive metabolites gerfelin and diorcinol
The Two-Phase, Two-Velocity Ionized Absorber in the Seyfert 1 Galaxy NGC 5548
We present an analysis of X-ray high quality grating spectra of the Seyfert 1
galaxy NGC 5548 using archival Chandra HETGS and LETGS observations for a total
exposure time of 800ks. The continuum emission is well represented by a
powerlaw plus a black-body component. We find that the well known X-ray warm
absorber in this source consists of two different outflow velocity systems.
Recognizing the presence of these kinematically distinct components allows each
system to be fitted independently, each with two absorption components with
different ionization levels. The high velocity system consists of a component
with temperature of 2.7X10^6K and another component with temperature of
5.8X10^5K. The low-velocity system required also two absorbing components, one
with temperature of 5.8X10^5K; the other with lower temperature (3.5X10^4K).
Once these components are considered, the data do not require any further
absorbers. In particular, a model consisting of a continuous radial range of
ionization structures is not required. The two absorbing components in each
velocity system are in pressure equilibrium with each other. This suggests that
each velocity system consists of a multi-phase medium. This is the first time
that different outflow velocity systems have been modelled independently in the
X-ray band for this source. The kinematic components and column densities found
from the X-rays are in agreement with the main kinematic components found in
the UV absorber. This supports the idea that the UV and X-ray absorbing gas is
part of the same phenomenon. NGC 5548 can now be seen to fit in a pattern
established for other warm absorbers: 2 or 3 discrete phases in pressure
equilibrium. There are no remaining cases of a well studied warm absorber in
which a model consisting of a multi-phase medium is not viable.Comment: To appear on The Astrophysical Journal March 1, 201
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Structure of CD20 in complex with the therapeutic monoclonal antibody rituximab.
Cluster of differentiation 20 (CD20) is a B cell membrane protein that is targeted by monoclonal antibodies for the treatment of malignancies and autoimmune disorders but whose structure and function are unknown. Rituximab (RTX) has been in clinical use for two decades, but how it activates complement to kill B cells remains poorly understood. We obtained a structure of CD20 in complex with RTX, revealing CD20 as a compact double-barrel dimer bound by two RTX antigen-binding fragments (Fabs), each of which engages a composite epitope and an extensive homotypic Fab:Fab interface. Our data suggest that RTX cross-links CD20 into circular assemblies and lead to a structural model for complement recruitment. Our results further highlight the potential relevance of homotypic Fab:Fab interactions in targeting oligomeric cell-surface markers
The PIAS-like Coactivator Zmiz1 Is a Direct and Selective Cofactor of Notch1 in T Cell Development and Leukemia
SummaryPan-NOTCH inhibitors are poorly tolerated in clinical trials because NOTCH signals are crucial for intestinal homeostasis. These inhibitors might also promote cancer because NOTCH can act as a tumor suppressor. We previously reported that the PIAS-like coactivator ZMIZ1 is frequently co-expressed with activated NOTCH1 in T cell acute lymphoblastic leukemia (T-ALL). Here, we show that similar to Notch1, Zmiz1 was important for T cell development and controlled the expression of certain Notch target genes, such as Myc. However, unlike Notch, Zmiz1 had no major role in intestinal homeostasis or myeloid suppression. Deletion of Zmiz1 impaired the initiation and maintenance of Notch-induced T-ALL. Zmiz1 directly interacted with Notch1 via a tetratricopeptide repeat domain at a special class of Notch-regulatory sites. In contrast to the Notch cofactor Maml, which is nonselective, Zmiz1 was selective. Thus, targeting the NOTCH1-ZMIZ1 interaction might combat leukemic growth while avoiding the intolerable toxicities of NOTCH inhibitors
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