1,789 research outputs found

    Geometric model from microscopic theory for nuclear absorption

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    A parameter-free geometric model for nuclear absorption is derived herein from microscopic theory. The expression for the absorption cross section in the eikonal approximation, taken in integral form, is separated into a geometric contribution that is described by an energy-dependent effective radius and two surface terms that cancel in an asymptotic series expansion. For collisions of light nuclei, an expression for the effective radius is derived from harmonic oscillator nuclear density functions. A direct extension to heavy nuclei with Woods-Saxon densities is made by identifying the equivalent half-density radius for the harmonic oscillator functions. Coulomb corrections are incorporated, and a simplified geometric form of the Bradt-Peters type is obtained. Results spanning the energy range from 1 MeV/nucleon to 1 GeV/nucleon are presented. Good agreement with experimental results is obtained

    A Pilot Study for Enhancing Postpartum Discharge Instructions for Incision Care: Assessment of Comprehension

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    Literacy and Health Care • 14.5% of United States is illiterate 1 • Reading level of most medical forms is 10th grade 2 Improving Outcomes with a Visual Aid • Cesarean Surgical Site Infection (SSI) rate is 5% 3 • A patient with a SSI can be 2 times as expensive 4 • Visual aids improve information recall 8 and confidence in wound care 5 Study Objectives 1. To evaluate the readability of the cesarean wound care discharge instructions relative to the patient population’s reading level 2. To conduct a pilot Randomized Control Trial (RCT) to evaluate the effectiveness of a visual aid on improving comprehension of the cesarean wound care instructionshttps://jdc.jefferson.edu/cwicposters/1034/thumbnail.jp

    Changes in DNA bending and flexing due to tethered cations detected by fluorescence resonance energy transfer

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    Local DNA deformation arises from an interplay among sequence-related base stacking, intrastrand phosphate repulsion, and counterion and water distribution, which is further complicated by the approach and binding of a protein. The role of electrostatics in this complex chemistry was investigated using tethered cationic groups that mimic proximate side chains. A DNA duplex was modified with one or two centrally located deoxyuracils substituted at the 5-position with either a flexible 3-aminopropyl group or a rigid 3-aminopropyn-1-yl group. End-to-end helical distances and duplex flexibility were obtained from measurements of the time-resolved Förster resonance energy transfer between 5′- and 3′-linked dye pairs. A novel analysis utilized the first and second moments of the G(t) function, which encompasses only the energy transfer process. Duplex flexibility is altered by the presence of even a single positive charge. In contrast, the mean 5′–3′ distance is significantly altered by the introduction of two adjacently tethered cations into the double helix but not by a single cation: two adjacent aminopropyl groups decrease the 5′–3′ distance while neighboring aminopropynyl groups lengthen the helix

    Fully energy-dependent HZETRN (a galactic cosmic-ray transport code)

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    For extended manned space missions, the radiation shielding design requires efficient and accurate cosmic-ray transport codes that can handle the physics processes in detail. The Langley Research Center galactic cosmic-ray transport code (HZETRN) is currently under development for such design use. The cross sections for the production of secondary nucleons in the existing HZETRN code are energy dependent only for nucleon collisions. The approximation of energy-independent, heavy-ion fragmentation cross section is now removed by implementing a mathematically simplified energy-dependent stepping formalism for heavy ions. The cross section at each computational grid is obtained by linear interpolation from a few tabulated data to minimize computing time. Test runs were made for galactic cosmic-ray transport through a liquid hydrogen shield and a water shield at solar minimum. The results show no appreciable change in total fluxes or computing time compared with energy-independent calculations. Differences in high LET (linear energy transfer) spectra are noted, however, because of the large variation in cross sections at the low-energy region. The high LET components are significantly higher in the new code and have important implications on biological risk estimates for heavy-ion exposure

    The SAMI Galaxy Survey: mass-kinematics scaling relations

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    We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass MM_* and the general kinematic parameter SK=KVrot2+σ2S_K = \sqrt{K V_{rot}^2 + \sigma^2} that combines rotation velocity VrotV_{rot} and velocity dispersion σ\sigma. We show that the logMlogSK\log M_* - \log S_K relation: (1)~is linear above limits set by properties of the samples and observations; (2)~has slightly different slope when derived from stellar or gas kinematic measurements; (3)~applies to both early-type and late-type galaxies and has smaller scatter than either the Tully-Fisher relation (logMlogVrot\log M_* - \log V_{rot}) for late types or the Faber-Jackson relation (logMlogσ\log M_* - \log\sigma) for early types; and (4)~has scatter that is only weakly sensitive to the value of KK, with minimum scatter for KK in the range 0.4 and 0.7. We compare SKS_K to the aperture second moment (the `aperture velocity dispersion') measured from the integrated spectrum within a 3-arcsecond radius aperture (σ3\sigma_{3^{\prime\prime}}). We find that while SKS_{K} and σ3\sigma_{3^{\prime\prime}} are in general tightly correlated, the logMlogSK\log M_* - \log S_K relation has less scatter than the logMlogσ3\log M_* - \log \sigma_{3^{\prime\prime}} relation.Comment: 14 pages, 8 figures, Accepted 2019 May 22. Received 2019 May 18; in original form 2019 January

    Prediction of congenital hypothyroidism based on initial screening thyroid-stimulating-hormone

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    Background: In thyroid-stimulating-hormone (TSH)-based newborn congenital hypothyroidism (CH) screening programs, the optimal screening-TSH cutoff level is critical to ensuring that true cases of CH are not missed. Screening-TSH results can also be used to predict the likelihood of CH and guide appropriate clinical management. The purpose of this study is to evaluate the predictive value of various screening-TSH levels in predicting a diagnosis of CH in the Ontario Newborn Screening Program (ONSP). Methods: The initial screening and follow-up data of 444,744 full term infants born in Ontario, Canada from April 1, 2006 to March 31, 2010 were analyzed. Confirmed CH cases were based on local endocrinologists\u27 report and initiation of thyroxine treatment. Results: There were a total of 541 positive screening tests (~1/822 live births) of which 296 were true positives (~1:1,500 live births). Subjects were further subdivided based on screening-TSH and positive predictive values (PPV) were calculated. Twenty four percent in the 17-19.9 mIU/L range were true positives. In the 17-30 mIU/L range, 29 % were true positives with a significantly higher PPV for those sampled after (43 %) rather than before (25 %) 28 h of age (p \u3c 0.02). Seventy three percent of neonates with an initial screening-TSH of ≥ 30 mIU/L and 97 % of those with ≥ 40 mIU/L were later confirmed to have CH. Conclusions: Infants with modestly elevated screening positive TSH levels between 17 and 19.9 mIU/L have a significant risk (24 %) of having CH. The very high frequency of true positives in term newborns with initial TSH values ≥ 30mIU/L suggests that this group should be referred directly to a pediatric endocrinologist in an effort to expedite further assessment and treatment. Screen positives with a modestly elevated TSH values (17-19.9 mIU/L) need to be examined in more detail with extended follow-up data to determine if they have transient or permanent CH

    Prediction of congenital hypothyroidism based on initial screening thyroid-stimulating-hormone

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    Background: In thyroid-stimulating-hormone (TSH)-based newborn congenital hypothyroidism (CH) screening programs, the optimal screening-TSH cutoff level is critical to ensuring that true cases of CH are not missed. Screening-TSH results can also be used to predict the likelihood of CH and guide appropriate clinical management. The purpose of this study is to evaluate the predictive value of various screening-TSH levels in predicting a diagnosis of CH in the Ontario Newborn Screening Program (ONSP). Methods: The initial screening and follow-up data of 444,744 full term infants born in Ontario, Canada from April 1, 2006 to March 31, 2010 were analyzed. Confirmed CH cases were based on local endocrinologists\u27 report and initiation of thyroxine treatment. Results: There were a total of 541 positive screening tests (~1/822 live births) of which 296 were true positives (~1:1,500 live births). Subjects were further subdivided based on screening-TSH and positive predictive values (PPV) were calculated. Twenty four percent in the 17-19.9 mIU/L range were true positives. In the 17-30 mIU/L range, 29 % were true positives with a significantly higher PPV for those sampled after (43 %) rather than before (25 %) 28 h of age (p \u3c 0.02). Seventy three percent of neonates with an initial screening-TSH of ≥ 30 mIU/L and 97 % of those with ≥ 40 mIU/L were later confirmed to have CH. Conclusions: Infants with modestly elevated screening positive TSH levels between 17 and 19.9 mIU/L have a significant risk (24 %) of having CH. The very high frequency of true positives in term newborns with initial TSH values ≥ 30mIU/L suggests that this group should be referred directly to a pediatric endocrinologist in an effort to expedite further assessment and treatment. Screen positives with a modestly elevated TSH values (17-19.9 mIU/L) need to be examined in more detail with extended follow-up data to determine if they have transient or permanent CH

    Shape Shifting Leads to Small-Molecule Allosteric Drug Discovery

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    SummaryEnzymes that regulate their activity by modulating an equilibrium of alternate, nonadditive, functionally distinct oligomeric assemblies (morpheeins) constitute a recently described mode of allostery. The oligomeric equilibrium for porphobilinogen synthase (PBGS) consists of high-activity octamers, low-activity hexamers, and two dimer conformations. A phylogenetically diverse allosteric site specific to hexamers is proposed as an inhibitor binding site. Inhibitor binding is predicted to draw the oligomeric equilibrium toward the low-activity hexamer. In silico docking enriched a selection from a small-molecule library for compounds predicted to bind to this allosteric site. In vitro testing of selected compounds identified one compound whose inhibition mechanism is species-specific conversion of PBGS octamers to hexamers. We propose that this strategy for inhibitor discovery can be applied to other proteins that use the morpheein model for allosteric regulation
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