1,053 research outputs found
Apparent equilibrium shifts and hot-spot formation for catalytic reactions induced by microwave dielectric heating
Microwave dielectric heating of the gas phase decomposition of H2S catalysed by metal sulfides on a -Al2O3 support results in significant apparent shifts in the equilibrium constant, which have been attributed to the development of hot-spots in the catalytic beds; X-ray diffraction and electron microscopy measurements have indicated the formation of hot-spots with dimensions of 90–1000 µm and which involve not only the active phase, but also the support
Toward the synthesis of an acetal-free Tn antigen anti-cancer vaccine candidate
Cancer vaccines are a promising approach to cancer treatment by activating the immune system towards cancer cells. The challenge, however, comes with the identification of biomarkers correlated with cancer. Unfortunately, many oncotargets are simply upregulated in cancer; these are inappropriate vaccine targets as they are also present on healthy cells and therefore would ultimately initiate a very dangerous systemic immune response. In contrast, Tumor-Associated Carbohydrate Antigens (TACAs) are not found in healthy adult tissue but are found on over 90% of biopsied carcinomas. When incorporated into glycopeptides or other immunogenic scaffolds, these carbohydrate antigens have formed the basis of the development of anti-tumor immunotherapies through the induction of a specific immune response against cancer cells. However, despite promising preliminary data, none of these candidates have reached the clinic. Our hypothesis is that the carbohydrates on the vaccines may not survive antigen processing, and so more stable versions of these materials are required to create viable vaccines.
Our approach is to incorporate TACAs lacking the labile glycosidic bond: acetal-free carbohydrates (AFCs). This project aims to remove the unstable acetal functional group to yield a more robust carbohydrate structure that can then be incorporated into a vaccine candidate. In this presentation, two synthetic pathways will be described: conversion of a carbohydrate to a carbasugar through a rearrangement, and de novo synthesis from noncarbohydrate materials
SIDM on FIRE: Hydrodynamical Self-Interacting Dark Matter simulations of low-mass dwarf galaxies
We compare a suite of four simulated dwarf galaxies formed in 10 haloes of collisionless Cold Dark Matter (CDM) with galaxies
simulated in the same haloes with an identical galaxy formation model but a
non-zero cross-section for dark matter self-interactions. These cosmological
zoom-in simulations are part of the Feedback In Realistic Environments (FIRE)
project and utilize the FIRE-2 model for hydrodynamics and galaxy formation
physics. We find the stellar masses of the galaxies formed in Self-Interacting
Dark Matter (SIDM) with are very similar to those in CDM
(spanning ) and all runs lie on a
similar stellar mass -- size relation. The logarithmic dark matter density
slope () in the central pc remains
steeper than for the CDM-Hydro simulations with stellar mass
and core-like in the most massive galaxy.
In contrast, every SIDM hydrodynamic simulation yields a flatter profile, with
. Moreover, the central density profiles predicted in SIDM runs
without baryons are similar to the SIDM runs that include FIRE-2 baryonic
physics. Thus, SIDM appears to be much more robust to the inclusion of
(potentially uncertain) baryonic physics than CDM on this mass scale,
suggesting SIDM will be easier to falsify than CDM using low-mass galaxies. Our
FIRE simulations predict that galaxies less massive than provide potentially ideal targets for discriminating models,
with SIDM producing substantial cores in such tiny galaxies and CDM producing
cusps.Comment: 10 Pages, 7 figures, submitted to MNRA
Apparent equilibrium shifts and hot-spot formation for catalytic reactions induced by microwave dielectric heating
Bibliografía
Reaction of the anion-deficient,
cation-ordered perovskite phase
Ba<sub>2</sub>YFeO<sub>5</sub> with 80 atm of oxygen pressure at 410
°C results in the formation of the Fe<sup>4+</sup> phase Ba<sub>2</sub>YFeO<sub>5.5</sub>. The topochemical insertion of oxide ions
lifts the inversion symmetry of the centrosymmetric host phase, Ba<sub>2</sub>YFeO<sub>5</sub> (space group <i>P</i>2<sub>1</sub>/<i>n</i>), to yield a noncentrosymmetric (NCS) phase Ba<sub>2</sub>YFeO<sub>5.5</sub> (space group <i>Pb</i>2<sub>1</sub><i>m</i> (No. 26), <i>a</i> = 12.1320(2) Å, <i>b</i> = 6.0606(1) Å, <i>c</i> = 8.0956(1) Å, <i>V</i> = 595.257(2) Å<sup>3</sup>) confirmed by the observation
of second-harmonic generation. Dielectric and PUND ferroelectric measurements,
however, show no evidence for a switchable ferroelectric polarization,
limiting the material to pyroelectric behavior. Magnetization and
low-temperature neutron diffraction data indicate that Ba<sub>2</sub>YFeO<sub>5.5</sub> undergoes a magnetic transition at 20 K to adopt
a state which exhibits a combination of ferromagnetic and antiferromagnetic
order. The symmetry breaking from centrosymmetric to polar noncentrosymmetric,
which occurs during the topochemical oxidation process is discussed
on the basis of induced lattice strain and an electronic instability
and represents a new strategy for the preparation of NCS materials
that readily incorporate paramagnetic transition metal centers
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A Phase II Basket Trial of Dual Anti-CTLA-4 and Anti-PD-1 Blockade in Rare Tumors (DART SWOG 1609) in Patients with Nonpancreatic Neuroendocrine Tumors.
PurposeImmune checkpoint blockade has improved outcomes across tumor types; little is known about the efficacy of these agents in rare tumors. We report the results of the (nonpancreatic) neuroendocrine neoplasm cohort of SWOG S1609 dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART).Patients and methodsWe performed a prospective, open-label, multicenter phase II clinical trial of ipilimumab plus nivolumab across multiple rare tumor cohorts, with the (nonpancreatic) neuroendocrine cohort reported here. Response assessment by grade was not prespecified. The primary endpoint was overall response rate [ORR; RECIST v1.1; complete response (CR) and partial response (PR)]; secondary endpoints included progression-free survival (PFS), overall survival (OS), stable disease >6 months, and toxicity.ResultsThirty-two eligible patients received therapy; 18 (56%) had high-grade disease. Most common primary sites were gastrointestinal (47%; N = 15) and lung (19%; N = 6). The overall ORR was 25% [95% confidence interval (CI) 13-64%; CR, 3%, N = 1; PR, 22%, N = 7]. Patients with high-grade neuroendocrine carcinoma had an ORR of 44% (8/18 patients) versus 0% in low/intermediate grade tumors (0/14 patients; P = 0.004). The 6-month PFS was 31% (95% CI, 19%-52%); median OS was 11 months (95% CI, 6-∞). The most common toxicities were hypothyroidism (31%), fatigue (28%), and nausea (28%), with alanine aminotransferase elevation (9%) as the most common grade 3/4 immune-related adverse event, and no grade 5 events.ConclusionsIpilimumab plus nivolumab demonstrated a 44% ORR in patients with nonpancreatic high-grade neuroendocrine carcinoma, with 0% ORR in low/intermediate grade disease
INTERNATIONAL VARIATION IN CARE AMONG PATIENTS HOSPITALIZED FOR HEART FAILURE: AN ANALYSIS OF THE ACUTE DECOMPENSATED HEART FAILURE NATIONAL REGISTRY UNITED STATES AND ACUTE DECOMPENSATED HEART FAILURE REGISTRY INTERNATIONAL
Quantity, composition, and source of sediment collected in sediment traps along the fringing coral reef off Molokai, Hawaii
This paper is not subject to U.S. copyright. The definitive version was published in Marine Pollution Bulletin 52 (2006): 1034-1047, doi:10.1016/j.marpolbul.2006.01.008.Sediment traps were used to evaluate the frequency, cause, and relative intensity of sediment mobility/resuspension along the fringing coral reef off southern Molokai (February 2000–May 2002). Two storms with high rainfall, floods, and exceptionally high waves resulted in sediment collection rates > 1000 times higher than during non-storm periods, primarily because of sediment resuspension by waves. Based on quantity and composition of trapped sediment, floods recharged the reef flat with land-derived sediment, but had a low potential for burying coral on the fore reef when accompanied by high waves.
The trapped sediments have low concentrations of anthropogenic metals. The magnetic properties of trapped sediment may provide information about the sources of land-derived sediment reaching the fore reef. The high trapping rate and low sediment cover indicate that coral surfaces on the fore reef are exposed to transient resuspended sediment, and that the traps do not measure net sediment accumulation on the reef surface
ᴅ-Mannose for prevention of recurrent urinary tract infection among women: a randomized clinical trial
Importance: Recurrent urinary tract infection (UTI) is a common debilitating condition in women, with limited prophylactic options. d-Mannose has shown promise in trials based in secondary care, but effectiveness in placebo-controlled studies and community settings has not been established.
Objective: To determine whether d-mannose taken for 6 months reduces the proportion of women with recurrent UTI experiencing a medically attended UTI.
Design, Setting, and Participants: This 2-group, double-blind randomized placebo-controlled trial took place across 99 primary care centers in the UK. Participants were recruited between March 28, 2019, and January 31, 2020, with 6 months of follow-up. Participants were female, 18 years or older, living in the community, and had evidence in their primary care record of consultations for at least 2 UTIs in the preceding 6 months or 3 UTIs in 12 months. Invitation to participate was made by their primary care center. A total of 7591 participants were approached, 830 responded, and 232 were ineligible or did not proceed to randomization. Statistical analysis was reported in December 2022.
Intervention: Two grams daily of d-mannose powder or matched volume of placebo powder.
Main Outcomes and Measures: The primary outcome measure was the proportion of women experiencing at least 1 further episode of clinically suspected UTI for which they contacted ambulatory care within 6 months of study entry. Secondary outcomes included symptom duration, antibiotic use, time to next medically attended UTI, number of suspected UTIs, and UTI-related hospital admissions.
Results: Of 598 women eligible (mean [range] age, 58 [18-93] years), 303 were randomized to d-mannose (50.7%) and 295 to placebo (49.3%). Primary outcome data were available for 583 participants (97.5%). The proportion contacting ambulatory care with a clinically suspected UTI was 150 of 294 (51.0%) in the d-mannose group and 161 of 289 (55.7%) in the placebo group (risk difference, −5%; 95% CI, −13% to 3%; P = .26). Estimates were similar in per protocol analyses, imputation analyses, and preplanned subgroups. There were no statistically significant differences in any secondary outcome measures.
Conclusions and Relevance: In this randomized clinical trial, daily d-mannose did not reduce the proportion of women with recurrent UTI in primary care who experienced a subsequent clinically suspected UTI. d-Mannose should not be recommended for prophylaxis in this patient group.
Trial Registration: isrctn.org Identifier: ISRCTN1328351
Type II Critical Collapse of a Self-Gravitating Nonlinear -Model
We report on the existence and phenomenology of type II critical collapse
within the one-parameter family of SU(2) -models coupled to gravity.
Numerical investigations in spherical symmetry show discretely self-similar
(DSS) behavior at the threshold of black hole formation for values of the
dimensionless coupling constant \ccbeta ranging from 0.2 to 100; at 0.18 we
see small deviations from DSS. While the echoing period of the
critical solution rises sharply towards the lower limit of this range, the
characteristic mass scaling has a critical exponent which is almost
independent of \ccbeta, asymptoting to at large
\ccbeta. We also find critical scaling of the scalar curvature for
near-critical initial data. Our numerical results are based on an
outgoing-null-cone formulation of the Einstein-matter equations, specialized to
spherical symmetry. Our numerically computed initial-data critical parameters
show 2nd order convergence with the grid resolution, and after
compensating for this variation in , our individual evolutions are
uniformly 2nd order convergent even very close to criticality.Comment: 23 pages, includes 10 postscript figure files, uses REVTeX, epsf,
psfrag, and AMS math fonts (amstex + amssymb); to appear in PRD15. Summary of
revisions from v2: fix wrong formula in figure 6 caption and y-axis label,
also minor wording changes and update publication status of refs 5-
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