1,355 research outputs found
Bepalen van de vochtinhoud en verdamping in de afzet van potplanten met behulp van een vochtmeting
A Hemoperfusion Column Based on Activated Carbon Granules Coated with an Ultrathin Membrane of Cellulose Acetate
A hemoperfusion system has been developed which makes use of activated carbon encapsulated with cellulose acetate. Studies have revealed that there are no stagnant flow regions in the column, there i? minimal particle release and the coating is 30 Å thick. The relationships between pore size, pore volume and surface area have been examined. Twenty-five patients in grade IV coma have been treated with the column for treatment of drug overdose or agricultural chemical poisoning; the clinical course of one meprobamate-poisoned patient is described in detail
Transient hygro- and hydro-expansion of freely and restrained dried paper: the fiber-network coupling
The transient dimensional changes during \textit{hygro}-expansion and
\textit{hydro}-expansion of freely and restrained dried, softwood and hardwood
sheets and fibers is monitored, to unravel the governing micro-mechanisms
occurring during gradual water saturation. The response of individual fibers is
measured using a full-field global digital height correlation method, which has
been extended to monitor the transient \textit{hydro}-expansion of fibers from
dry to fully saturated. The \textit{hygro}- and \textit{hydro}-expansion is
larger for freely versus restrained dried and softwood versus hardwood
handsheets. The transient sheet-scale \textit{hydro}-expansion reveals a sudden
strain and moisture content step. It is postulated that the driving mechanism
is the moisture-induced softening of the so-called "dislocated regions" in the
fiber's cellulose micro-fibrils, unlocking further fiber swelling. The strain
step is negligible for restrained dried handsheets, which is attributed to the
"dislocated cellulose regions" being locked in their stretched configuration
during restrained drying, which is supported by the single fiber
\textit{hydro}-expansion measurements. Finally, an inter-fiber bond model is
exploited and adapted to predict the sheet-scale \textit{hygro}-expansion from
the fiber level characteristics. The model correctly predicts the qualitative
differences between freely versus restrained dried and softwood versus hardwood
handsheets, yet, its simplified geometry does not allow for more quantitative
predictions of the sheet-scale \textit{hydro}-expansion.Comment: 37 pages; 12 figures; 5 table
Direct Integration of the Topological String
We present a new method to solve the holomorphic anomaly equations governing
the free energies of type B topological strings. The method is based on direct
integration with respect to the non-holomorphic dependence of the amplitudes,
and relies on the interplay between non-holomorphicity and modularity
properties of the topological string amplitudes. We develop a formalism valid
for any Calabi-Yau manifold and we study in detail two examples, providing
closed expressions for the amplitudes at low genus, as well as a discussion of
the boundary conditions that fix the holomorphic ambiguity. The first example
is the non-compact Calabi-Yau underlying Seiberg-Witten theory and its
gravitational corrections. The second example is the Enriques Calabi-Yau, which
we solve in full generality up to genus six. We discuss various aspects of this
model: we obtain a new method to generate holomorphic automorphic forms on the
Enriques moduli space, we write down a new product formula for the fiber
amplitudes at all genus, and we analyze in detail the field theory limit. This
allows us to uncover the modularity properties of SU(2), N=2 super Yang-Mills
theory with four massless hypermultiplets.Comment: 75 pages, 3 figure
Twistor Strings with Flavour
We explore the tree-level description of a class of N=2 UV-finite SYM
theories with fundamental flavour within a topological B-model twistor string
framework. In particular, we identify the twistor dual of the Sp(N) gauge
theory with one antisymmetric and four fundamental hypermultiplets, as well as
that of the SU(N) theory with 2N hypermultiplets. This is achieved by suitably
orientifolding/orbifolding the original N=4 setup of Witten and adding a
certain number of new topological 'flavour'-branes at the orientifold/orbifold
fixed planes to provide the fundamental matter. We further comment on the
appearance of these objects in the B-model on CP(3|4). An interesting aspect of
our construction is that, unlike the IIB description of these theories in terms
of D3 and D7-branes, on the twistor side part of the global flavour symmetry is
realised geometrically. We provide evidence for this correspondence by
calculating and matching amplitudes on both sides.Comment: 38+12 pages; uses axodraw.sty. v2: References added, minor
clarification
Built-in and induced polarization across LaAlO/SrTiO heterojunctions
Ionic crystals terminated at oppositely charged polar surfaces are inherently
unstable and expected to undergo surface reconstructions to maintain
electrostatic stability. Essentially, an electric field that arises between
oppositely charged atomic planes gives rise to a built-in potential that
diverges with thickness. In ultra thin film form however the polar crystals are
expected to remain stable without necessitating surface reconstructions, yet
the built-in potential has eluded observation. Here we present evidence of a
built-in potential across polar \lao ~thin films grown on \sto ~substrates, a
system well known for the electron gas that forms at the interface. By
performing electron tunneling measurements between the electron gas and a
metallic gate on \lao ~we measure a built-in electric field across \lao ~of 93
meV/\AA. Additionally, capacitance measurements reveal the presence of an
induced dipole moment near the interface in \sto, illuminating a unique
property of \sto ~substrates. We forsee use of the ionic built-in potential as
an additional tuning parameter in both existing and novel device architectures,
especially as atomic control of oxide interfaces gains widespread momentum.Comment: 6 pages, 4 figures. Submitted to Nature physics on May 1st, 201
A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with systemic sclerosis in a large European cohort
<p><b>Objectives</b> The aim of this study was to confirm the influence of TNFSF4 polymorphisms on systemic sclerosis (SSc) susceptibility and phenotypic features.</p>
<p><b>Methods</b> A total of 8 European populations of Caucasian ancestry were included, comprising 3014 patients with SSc and 3125 healthy controls. Four genetic variants of TNFSF4 gene promoter (rs1234314, rs844644, rs844648 and rs12039904) were selected as genetic markers.</p>
<p><b>Results</b> A pooled analysis revealed the association of rs1234314 and rs12039904 polymorphisms with SSc (OR 1.15, 95% CI 1.02 to 1.31; OR 1.18, 95% CI 1.08 to 1.29, respectively). Significant association of the four tested variants with patients with limited cutaneous SSc (lcSSc) was revealed (rs1234314 OR 1.22, 95% CI 1.07 to 1.38; rs844644 OR 0.91, 95% CI 0.83 to 0.99; rs844648 OR 1.10, 95% CI 1.01 to 1.20 and rs12039904 OR 1.20, 95% CI 1.09 to 1.33). Association of rs1234314, rs844648 and rs12039904 minor alleles with patients positive for anti-centromere antibodies (ACA) remained significant (OR 1.23, 95% CI 1.10 to 1.37; OR 1.12, 95% CI 1.01 to 1.25; OR 1.22, 95% CI 1.07 to 1.38, respectively). Haplotype analysis confirmed a protective haplotype associated with SSc, lcSSc and ACA positive subgroups (OR 0.88, 95% CI 0.82 to 0.96; OR 0.88, 95% CI 0.80 to 0.96; OR 0.86, 95% CI 0.77 to 0.97, respectively) and revealed a new risk haplotype associated with the same groups of patients (OR 1.14, 95% CI 1.03 to 1.26; OR 1.20, 95% CI 1.08 to 1.35; OR 1.23, 95% CI 1.07 to 1.42, respectively).</p>
<p><b>Conclusions</b> The data confirm the influence of TNFSF4 polymorphisms in SSc genetic susceptibility, especially in subsets of patients positive for lcSSc and ACA.</p>
The Effect of Provider Density on Lung Cancer Survival Among Blacks and Whites in the United States
IntroductionLung cancer mortality rates may vary with access to specialty providers and local resources. We sought to examine the effect of access to care, using density of lung cancer care providers, on lung cancer mortality among blacks and whites in the United States.MethodsWe examined U.S. county-level data for age-adjusted lung cancer mortality rates from 2003 to 2007. Our primary independent variable was per capita number of thoracic oncologic providers, adjusting for county-level smoking rates, socioeconomic status, and other geographic factors. Data were obtained from 2009 Area Resource File, National Center for Health Statistics, and the County Health Rankings Project.ResultsProviders of lung cancer care were unevenly distributed among the U.S. counties. For example, 41.4% of the U.S. population reside in counties with less than four thoracic surgeons per 100,000 people, 23.4% in counties with 4 to 15 surgeons per 100,000 people, and 35.3% in counties with more than 15 surgeons per 100,000 people. Geographically, 4.3% of whites compared with 11.2% of blacks lived in high lung cancer mortality zones. Lung cancer mortality did not vary by density of thoracic surgeons or oncology services; however, higher primary care provider density was associated with lung cancer mortality reduction of 4.1 per 100,000 for whites.ConclusionVariation in provider density for thoracic oncology in the United States was not associated with a difference in lung cancer mortality. Lower mortality associated with higher primary care provider density suggests that equitable access to primary care may lead to reduced cancer disparities
Evidence for reverse cholesterol transport in vivo from liver endothelial cells to parenchymal cells and bile by high-density lipoprotein
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