256 research outputs found
Securing Liberty with Chains: Locking up the Fifth Amendment within the Confines of Miranda Dickerson v. United States
Note
Nucleation at the DNA supercoiling transition
Twisting DNA under a constant applied force reveals a thermally activated
transition into a state with a supercoiled structure known as a plectoneme.
Using transition state theory, we predict the rate of this plectoneme
nucleation to be of order 10^4 Hz. We reconcile this with experiments that have
measured hopping rates of order 10 Hz by noting that the viscosity of the bead
used to manipulate the DNA limits the measured rate. We find that the intrinsic
bending caused by disorder in the base-pair sequence is important for
understanding the free energy barrier that governs the transition. Both
analytic and numerical methods are used in the calculations. We provide
extensive details on the numerical methods for simulating the elastic rod model
with and without disorder.Comment: 18 pages, 15 figure
High-temperature-grown buffer layer boosts electron mobility in epitaxial La-doped BaSnO/SrZrO heterostructures
By inserting a SrZrO buffer layer between the film and the substrate, we
demonstrate a significant reduction of the threading dislocation density with
an associated improvement of the electron mobility in La:BaSnO films. A
room temperature mobility of 140 cm V is achieved for
25-nm-thick films without any post-growth treatment. The density of threading
dislocations is only cm for buffered films prepared
on (110) TbScO substrates by pulsed laser deposition.Comment: 5 pages, 4 figure
A Titanium Nitride Absorber for Controlling Optical Crosstalk in Horn-Coupled Aluminum LEKID Arrays for Millimeter Wavelengths
We discuss the design and measured performance of a titanium nitride (TiN)
mesh absorber we are developing for controlling optical crosstalk in
horn-coupled lumped-element kinetic inductance detector arrays for
millimeter-wavelengths. This absorber was added to the fused silica
anti-reflection coating attached to previously-characterized, 20-element
prototype arrays of LEKIDs fabricated from thin-film aluminum on silicon
substrates. To test the TiN crosstalk absorber, we compared the measured
response and noise properties of LEKID arrays with and without the TiN mesh.
For this test, the LEKIDs were illuminated with an adjustable, incoherent
electronic millimeter-wave source. Our measurements show that the optical
crosstalk in the LEKID array with the TiN absorber is reduced by 66\% on
average, so the approach is effective and a viable candidate for future
kilo-pixel arrays.Comment: 7 pages, 5 figures, accepted for publication in the Journal of Low
Temperature Physic
Combined Spectroscopy and Electrical Characterization of La:BaSnO Thin Films and Heterostructures
For La-doped BaSnO thin films grown by pulsed laser deposition, we
combine chemical surface characterization and electronic transport studies to
probe the evolution of electronic states in the band structure for different
La-doping content. Systematic analyses of spectroscopic data based on fitting
the core electron line shapes help to unravel the composition of the surface as
well as the dynamics associated with increasing doping. This dynamics is
observed with a more pronounced signature in the Sn 3d core level, which
exhibits an increasing asymmetry to the high binding energy side of the peak
with increasing electron density. The present results expand the current
understanding of the interplay between the doping concentration, electronic
band structure and transport properties of epitaxial La:BaSnO films.Comment: 7 Figures, 4 Tables in manuscript; and 6 Figures and 1 Table in the
Supplementary Informatio
Soil bacterial community structure and functional responses across a long-term mineral phosphorus (Pi) fertilisation gradient differ in grazed and cut grasslands
peer-reviewedGrasslands form a significant proportion of land used across the globe and future management is important. The objective of this study was to compare the long-term impact of inorganic phosphorus (Pi) fertilisation rates (P0, P15 and P30 ha−1 yr−1) under two grass management trials (grazed vs. cut and removed) on soil physicochemical properties, microbial biomass, phosphomonoesterase activity, bacterial community structure and abundance of a phosphorus (P) mineralising gene (phoD). Under grazing, microbial biomass and soil phosphorus concentrations (total and Pi) generally increased with Pi fertilisation rate, accompanied by significant differences in bacterial community structure between unfertilised (P0) and P30 soil. At the cut and removed site, although Pi was significantly greater in P30 soil, P concentrations (total and Pi) did not increase to the same extent as for grazing, with microbial biomass and bacterial community structures unresponsive to Pi fertilisation. Despite differences in soil P concentrations (total and Pi) and microbial biomass between sites, the abundance of bacterial phoD increased with increasing soil Pi across both sites, while phosphomonoesterase activity decreased. Amplicon sequencing revealed Acidobacteria were the dominant bacterial phylum across both grasslands, but significant differences in relative abundances of bacterial genera were detected at the grazed site only. The bacterial genera Gp6 and Gp16 increased significantly with Pi fertilisation under grazing. Conversely, Bradyrhizobium as well as unclassified genus-type groups belonging to Actinobacteria and Acidimicrobiales significantly decreased with Pi fertilisation, suggesting potential roles in P mobilisation when soil Pi concentrations are low. This study highlights the importance of long-term Pi fertilisation rates and aboveground vegetation removal in shaping soil bacterial community structure and microbial biomass, which in turn may impact soil fertility and plant productivity within agricultural soils
Economic evaluation of the specialized donor care facility for thoracic organ donor management
Background: Over the last decade two alternative models of donor care have emerged in the United States: the conventional model, whereby donors are managed at the hospital where brain death occurs, and the specialized donor care facility (SDCF), in which brain dead donors are transferred to a SDCF for medical optimization and organ procurement. Despite increasing use of the SDCF model, its cost-effectiveness in comparison to the conventional model remains unknown.
Methods: We performed an economic evaluation of the SDCF and conventional model of donor care from the perspective of U.S. transplant centers over a 2-year study period. In this analysis, we utilized nationwide data from the Scientific Registry of Transplant Recipients and controlled for donor characteristics and patterns of organ sharing across the nation\u27s organ procurement organizations (OPOs). Subgroup analysis was performed to determine the impact of the SDCF model on thoracic organ transplants.
Results: A total of 38,944 organ transplants were performed in the U.S. during the study period from 13,539 donors with an observed total organ cost of 1.26 billion (-24.6 million.
Conclusions: The U.S. SDCF model may be a less costly and more effective means of multi-organ donor management, particularly for thoracic organ donors, compared to the conventional hospital-based model
Development of multi-chroic MKIDs for next-generation CMB polarization studies
We report on the status of an ongoing effort to develop arrays of horn-coupled, polarization-sensitive microwave kinetic inductance detectors (MKIDs) that are each sensitive to two spectral bands between 125 and 280 GHz. These multi-chroic MKID arrays are tailored for next-generation, large-detector-count experiments that are being designed to simultaneously characterize the polarization properties of both the cosmic microwave background and Galactic dust emission. We present our device design and describe laboratory-based measurement results from two 23-element prototype arrays. From dark measurements of our first engineering array, we demonstrated a multiplexing factor of 92, showed the resonators respond to bath temperature changes as expected, and found that the fabrication yield was 100%. From our first optically loaded array, we found the MKIDs respond to millimeter-wave pulses; additional optical characterization measurements are ongoing. We end by discussing our plans for scaling up this technology to kilo-pixel arrays over the next 2 years
Baseline Gastrointestinal Eosinophilia Is Common in Oral Immunotherapy Subjects With IgE-Mediated Peanut Allergy
Rationale: Oral immunotherapy (OIT) is an emerging treatment for food allergy. While desensitization is achieved in most subjects, many experience gastrointestinal symptoms and few develop eosinophilic gastrointestinal disease. It is unclear whether these subjects have subclinical gastrointestinal eosinophilia (GE) at baseline. We aimed to evaluate the presence of GE in subjects with food allergy before peanut OIT.Methods: We performed baseline esophagogastroduodenoscopies on 21 adults before undergoing peanut OIT. Subjects completed a detailed gastrointestinal symptom questionnaire. Endoscopic findings were assessed using the Eosinophilic Esophagitis (EoE) Endoscopic Reference Score (EREFS) and biopsies were obtained from the esophagus, gastric antrum, and duodenum. Esophageal biopsies were evaluated using the EoE Histologic Scoring System. Immunohistochemical staining for eosinophil peroxidase (EPX) was also performed. Hematoxylin and eosin and EPX stains of each biopsy were assessed for eosinophil density and EPX/mm2 was quantified using automated image analysis.Results: All subjects were asymptomatic. Pre-existing esophageal eosinophilia (>5 eosinophils per high-power field [eos/hpf]) was present in five participants (24%), three (14%) of whom had >15 eos/hpf associated with mild endoscopic findings (edema, linear furrowing, or rings; median EREFS = 0, IQR 0–0.25). Some subjects also demonstrated basal cell hyperplasia, dilated intercellular spaces, and lamina propria fibrosis. Increased eosinophils were noted in the gastric antrum (>12 eos/hpf) or duodenum (>26 eos/hpf) in 9 subjects (43%). EPX/mm2 correlated strongly with eosinophil counts (r = 0.71, p < 0.0001).Conclusions: Pre-existing GE is common in adults with IgE-mediated peanut allergy. Eosinophilic inflammation (EI) in these subjects may be accompanied by mild endoscopic and histologic findings. Longitudinal data collection during OIT is ongoing
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