2,777 research outputs found
Early hospital readmissions post‐kidney transplantation are associated with inferior clinical outcomes
Unplanned hospital readmissions are common early post‐kidney transplantation. We investigated the relationship between early hospital readmissions and clinical outcomes in a single‐center retrospective study that included all adult kidney transplant patients between 2004 and 2008 with follow‐up to December 2012. The early hospital readmissions within the first 30 d were numbered and the diagnosis ascertained. Patients were grouped as none, once, and twice or more readmissions. Predictors of early readmissions were assessed, and clinical outcomes and patient and death‐censored kidney survival were compared. Among 1064 patients, 203 (19.1%) patients had once and 83 (7.8%) patients had twice or more readmissions within 30 d. Surgical complications, infections, and acute kidney injuries/acute rejection were three most common diagnoses. The length of initial hospital stay and African American race were among the variables associated significantly with readmissions. Patients with early readmissions had lower baseline renal function (p < 0.01) and more early acute rejection (p < 0.01). During follow‐up, only frequent readmissions, twice or more, within 30 d were associated with increased risk of death ( AHR 1.75, p = 0.01) and death‐censored kidney failure ( AHR 2.20, p < 0.01). Frequent early hospital readmissions post‐transplantation identify patients at risk for poor long‐term outcomes, and more studies are needed to understand the mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106830/1/ctr12347.pd
Contact and Friction of Nano-Asperities: Effects of Adsorbed Monolayers
Molecular dynamics simulations are used to study contact between a rigid,
nonadhesive, spherical tip with radius of order 30nm and a flat elastic
substrate covered with a fluid monolayer of adsorbed chain molecules. Previous
studies of bare surfaces showed that the atomic scale deviations from a sphere
that are present on any tip constructed from discrete atoms lead to significant
deviations from continuum theory and dramatic variability in friction forces.
Introducing an adsorbed monolayer leads to larger deviations from continuum
theory, but decreases the variations between tips with different atomic
structure. Although the film is fluid, it remains in the contact and behaves
qualitatively like a thin elastic coating except for certain tips at high
loads. Measures of the contact area based on the moments or outer limits of the
pressure distribution and on counting contacting atoms are compared. The number
of tip atoms making contact in a time interval grows as a power of the interval
when the film is present and logarithmically with the interval for bare
surfaces. Friction is measured by displacing the tip at a constant velocity or
pulling the tip with a spring. Both static and kinetic friction rise linearly
with load at small loads. Transitions in the state of the film lead to
nonlinear behavior at large loads. The friction is less clearly correlated with
contact area than load.Comment: RevTex4, 17 pages, 13 figure
Screening of external magnetic perturbation fields due to sheared plasma flow
Within the single fluid resistive magnetohydrodynamic model, systematic toroidal modelling efforts are devoted to investigate the plasma response induced screening of the applied external 3D magnetic field perturbations in the presence of sheared toroidal flow. One particular issue of interest is addressed, when the local flow speed approaches zero at the perturbation rational surface inside the plasma. Subtle screening physics, associated with the favourable averaged toroidal curvature effect (the GGJ effect (Glasser et al 1975 Phys. Fluids 7 875)), is found to play an essential role during slow flow near the rational surface by enhancing the screening at reduced flow. A strong cancellation effect between different terms of Ohm's law is discovered, leading to different screening physics in the GGJ regime, as compared to that of conventional screening of the typical resistive-inertial regime occurring at faster flow. These modelling results may be applicable to interpret certain mode locking experiments, as well as type-I edge localized mode suppression experiments, with resonant magnetic field perturbations being applied to tokamak plasmas at low input toroidal torque
[Colored solutions of Yang-Baxter equation from representations of U_{q}gl(2)]
We study the Hopf algebra structure and the highest weight representation of
a multiparameter version of . The commutation relations as well as
other Hopf algebra maps are explicitly given. We show that the multiparameter
universal matrix can be constructed directly as a quantum double
intertwiner, without using Reshetikhin's transformation. An interesting feature
automatically appears in the representation theory: it can be divided into two
types, one for generic , the other for being a root of unity. When
applying the representation theory to the multiparameter universal
matrix, the so called standard and nonstandard colored solutions of the Yang-Baxter equation is obtained.Comment: [14]pages, latex, no figure
Characterization of high-resolution aerosol mass spectra of primary organic aerosol emissions from Chinese cooking and biomass burning
Aerosol mass spectrometry has proved to be a powerful tool to measure
submicron particulate composition with high time resolution. Factor analysis
of mass spectra (MS) collected worldwide by aerosol mass spectrometer (AMS)
demonstrates that submicron organic aerosol (OA) is usually composed of
several major components, such as oxygenated (OOA), hydrocarbon-like (HOA),
biomass burning (BBOA), and other primary OA. In order to help
interpretation of component MS from factor analysis of ambient OA datasets,
AMS measurements of different primary sources is required for comparison.
Such work, however, has been very scarce in the literature, especially for
high resolution MS (HR-MS) measurements, which performs improved
characterization by separating the ions of different elemental composition
at each <i>m</i>/<i>z</i> in comparison with unit mass resolution MS (UMR-MS)
measurements. In this study, primary emissions from four types of Chinese
cooking (CC) and six types of biomass burning (BB) were simulated
systematically and measured using an Aerodyne High-Resolution Time-of-Flight
AMS (HR-ToF-AMS). The MS of the CC emissions show high similarity, with <i>m</i>/<i>z</i>
41 and <i>m</i>/<i>z</i> 55 being the highest signals; the MS of the BB emissions also
show high similarity, with <i>m</i>/<i>z</i> 29 and <i>m</i>/<i>z</i> 43 being the highest signals. The
MS difference between the CC and BB emissions is much bigger than that
between different CC (or BB) types, especially for the HR-MS. The O/C ratio
of OA ranges from 0.08 to 0.13 for the CC emissions and from 0.18 to 0.26
for the BB emissions. The UMR ions of <i>m</i>/<i>z</i> 43, <i>m</i>/<i>z</i> 44, <i>m</i>/<i>z</i> 57, and <i>m</i>/<i>z</i> 60,
usually used as tracers in AMS measurements, were examined for their HR-MS
characteristics in the CC and BB emissions. In addition, the MS of the CC
and BB emissions are also compared with component MS from factor analysis of
ambient OA datasets observed in China, as well as with other AMS
measurements of primary sources in the literature. The MS signatures of
cooking and biomass burning emissions revealed in this study can be used as
important reference for factor analysis of ambient OA datasets, especially
for the relevant studies in East Asia
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Spatial-temporal dynamics of grain yield and the potential driving factors at the county level in China
© 2020 Elsevier Ltd Understanding the spatial-temporal dynamics of grain production and the influencing factors at the county level in China may promote the knowledge of land-use management and local policymaking, which are conducive to food security and the sustainable development of society. This study aims to evaluate China's grain yield (GY) from 2000 to 2014 and investigate the potential driving factors (PDFs) that affect the spatial-temporal dynamics of GY, including land, labor force, capital, and macro-background. Specifically, the locational Gini coefficient and exploratory spatial data analysis (ESDA) were used to characterize the spatial patterns of GY and its correlations with PDFs. Spatial regression models (SRMs) were employed to investigate the spatial dependence of GY on each PDF in 2000, 2005, 2010 and 2014. Results reveal that China's grain production has been on the rise with high-yield regions distributed mainly within the northeastern agricultural regions. Moreover, the proportion of counties in the northeastern agricultural regions with high grain yield has increased, while the number of low-yielding counties has increased in other agricultural regions. This finding highlights the increasing trend of spatial polarization in grain production. The significant bivariate Moran's I (p < 0.05) further revealed a global spatial spillover effect in the spatial correlation of GY and four PDFs. The spatial correlations could be categorized into four types: high GY and high PDFs, high GY and low PDFs, low GY and high PDFs, and low GY and low PDFs. SRMs were capable of quantifying the spatial dependence of GY on various PDFs, thereby revealing that land factors had a substantial effect on the grain production dynamics nationwide. The exploration of the spatial relationships between GY and PDFs provide a reference for formulating scientific and reasonable agricultural policies
PEGylated bottom-up synthesized graphene nanoribbons loaded with camptothecin as potential drug carriers
This work discusses the potential use of bottom-up synthesized graphene nanoribbons (GNRs) as nano-carriers for drug delivery systems (DDSs). GNRs have a high loading capacity for anticancer drugs due to their high specific surface area and non-covalent adsorption with hydrophobic anticancer drug molecules. Herein, we synthesized GNRs using a bottom-up approach, modified with PEG2000 (GNR-PEG) and PEG2000 carrying folic acid chains (GNR-PEG-FA), and then loaded with camptothecin (CPT). The targeting ability mediated by folic acid of the GNR derivative was evaluated using cellular assays, and the cytotoxicity of GNR systems loaded with CPT was assessed by in vitro studies. They suggest that the functionalization of GNR derivatives with folic acid significantly affects their interaction with cells expressing different levels of folic acid receptors. The authors also explore the possibility to employ GNRs in photothermal therapy (PTT). GNR-PEG and GNR-PEG-FA display minor or no toxicity in standard cell cultures, but they show remarkable thermal response upon NIR irradiation, causing complete loss of cell viability within a few hours of treatment. This work highlights the potential of GNRs as DDSs and emphasizes the importance of further research on their biocompatibility and as a platform for PTT
Factor Analysis and the Social Capital Index: A Study at the Brazil / Bolivia Border
Objective: The study aimed to build the level of social capital by neighborhoods Guajará-Mirim border region between the State of Rondônia, Brazil and the Republic of Bolivia, which in recent years has been showing signs of social fragility due advance not virtuous practices. Method: This work made use of research in secondary bases as well as in primary bases. The tabulation of qualitative and quantitative data was performed in Excel (2010) and for their processing performance index construction purposes were calculated following the factorial analysis techniques presented by Hair et al. [19] Santana [20, 21]; and Choi [22]. For this, we made use of the statistical tool SPSS (Statistical Package for Social Sciences) for the construction of the indices of social capital. The correlation analysis process was done in Excel. results: It was observed that the capital reached regular levels in Guajará-Mirim neighborhoods not observable, so correlations between the studied parameters, however, it needs to be further studied as factors such as the flooding of the Mamore river may have interfered in any way in the implementation process of the field survey to the residents of the city. It became clear that the municipality of Guajará-Mirim suffers from serious social problems and that most problems are correlated with the increase in alcoholic beverage market in the city and use drugs. However, was not observed as the institutional arrangements are dealing with this problem, that is, as public bodies are relating to discuss actions for concrete solutions to this evil that plagues large portion of the population of Guajará-Mirim, mainly young teenagers residents of Guajá-Mamim. However, we hope to continue this work in order to better understand this mechanism of social network between the actors of this process in the region
Quantitative nanoscale vortex-imaging using a cryogenic quantum magnetometer
Microscopic studies of superconductors and their vortices play a pivotal role
in our understanding of the mechanisms underlying superconductivity. Local
measurements of penetration depths or magnetic stray-fields enable access to
fundamental aspects of superconductors such as nanoscale variations of
superfluid densities or the symmetry of their order parameter. However,
experimental tools, which offer quantitative, nanoscale magnetometry and
operate over the large range of temperature and magnetic fields relevant to
address many outstanding questions in superconductivity, are still missing.
Here, we demonstrate quantitative, nanoscale magnetic imaging of Pearl vortices
in the cuprate superconductor YBCO, using a scanning quantum sensor in form of
a single Nitrogen-Vacancy (NV) electronic spin in diamond. The sensor-to-sample
distance of ~10nm we achieve allows us to observe striking deviations from the
prevalent monopole approximation in our vortex stray-field images, while we
find excellent quantitative agreement with Pearl's analytic model. Our
experiments yield a non-invasive and unambiguous determination of the system's
local London penetration depth, and are readily extended to higher temperatures
and magnetic fields. These results demonstrate the potential of quantitative
quantum sensors in benchmarking microscopic models of complex electronic
systems and open the door for further exploration of strongly correlated
electron physics using scanning NV magnetometry.Comment: Main text (5 pages, 4 figures) plus supplementary material (5 pages,
6 figures). Comments welcome. Further information under
http://www.quantum-sensing.c
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