1,183 research outputs found
On the Large Time Behavior of Solutions of Hamilton-Jacobi Equations Associated with Nonlinear Boundary Conditions
In this article, we study the large time behavior of solutions of first-order
Hamilton-Jacobi Equations, set in a bounded domain with nonlinear Neumann
boundary conditions, including the case of dynamical boundary conditions. We
establish general convergence results for viscosity solutions of these
Cauchy-Neumann problems by using two fairly different methods : the first one
relies only on partial differential equations methods, which provides results
even when the Hamiltonians are not convex, and the second one is an optimal
control/dynamical system approach, named the "weak KAM approach" which requires
the convexity of Hamiltonians and gives formulas for asymptotic solutions based
on Aubry-Mather sets
Involvement of (pro)renin receptor in the glomerular filtration barrier
(Pro)renin receptor-bound prorenin not only causes the generation of angiotensin II via the nonproteolytic activation of prorenin, it also activates the receptor’s own intracellular signaling pathways independent of the generated angiotensin II. Within the kidneys, the (pro)renin receptor is not only present in the glomerular mesangium, it is also abundant in podocytes, which play an important role in the maintenance of the glomerular filtration barrier. Recent in vivo studies have demonstrated that the overexpression of the (pro)renin receptor to a degree similar to that observed in hypertensive rat kidneys leads to slowly progressive nephropathy with proteinuria. In addition, the handle region peptide, which acts as a decoy peptide and competitively inhibits the binding of prorenin to the receptor, is more beneficial than an angiotensin-converting enzyme inhibitor with regard to alleviating proteinuria and glomerulosclerosis in experimental animal models of diabetes and essential hypertension. Thus, the (pro)renin receptor may be upregulated in podocytes under hypertensive conditions and may contribute to the breakdown of the glomerular filtration barrier
BactMAP:An R package for integrating, analyzing and visualizing bacterial microscopy data
High-throughput analyses of single-cell microscopy data are a critical tool within the field of bacterial cell biology. Several programs have been developed to specifically segment bacterial cells from phase-contrast images. Together with spot and object detection algorithms, these programs offer powerful approaches to quantify observations from microscopy data, ranging from cell-to-cell genealogy to localization and movement of proteins. Most segmentation programs contain specific post-processing and plotting options, but these options vary between programs and possibilities to optimize or alter the outputs are often limited. Therefore, we developed BactMAP (Bacterial toolbox for Microscopy Analysis & Plotting), a command-line based R package that allows researchers to transform cell segmentation and spot detection data generated by different programs into various plots. Furthermore, BactMAP makes it possible to perform custom analyses and change the layout of the output. Because BactMAP works independently of segmentation and detection programs, inputs from different sources can be compared within the same analysis pipeline. BactMAP complies with standard practice in R which enables the use of advanced statistical analysis tools, and its graphic output is compatible with ggplot2, enabling adjustable plot graphics in every operating system. User feedback will be used to create a fully automated Graphical User Interface version of BactMAP in the future. Using BactMAP, we visualize key cell cycle parameters in Bacillus subtilis and Staphylococcus aureus, and demonstrate that the DNA replication forks in Streptococcus pneumoniae dissociate and associate before splitting of the cell, after the Z-ring is formed at the new quarter positions. BactMAP is available from https://veeninglab.com/bactmap
1+1 dimensional QCD with fundamental bosons and fermions
We analyze the properties of mesons in 1+1 dimensional QCD with bosonic and
fermionic ``quarks'' in the large \nc limit. We study the spectrum in detail
and show that it is impossible to obtain massless mesons including boson
constituents in this model. We quantitatively show how the QCD mass inequality
is realized in two dimensional QCD. We find that the mass inequality is close
to being an equality even when the quarks are light. Methods for obtaining the
properties of ``mesons'' formed from boson and/or fermion constituents are
formulated in an explicit manner convenient for further study. We also analyze
how the physical properties of the mesons such as confinement and asymptotic
freedom are realized.Comment: 20 pages, harvmac, 5 figure
Multi-layer scintillation detector for the MOON double beta decay experiment: Scintillation photon responses studied by a prototype detector MOON-1
An ensemble of multi-layer scintillators is discussed as an option of the
high-sensitivity detector Mo Observatory Of Neutrinos (MOON) for spectroscopic
measurements of neutrino-less double beta decays. A prototype detector MOON-1,
which consists of 6 layer plastic-scintillator plates, was built to study the
sensitivity of the MOON-type detector. The scintillation photon collection and
the energy resolution, which are key elements for the high-sensitivity
experiments, are found to be 1835+/-30 photo-electrons for 976 keV electrons
and sigma = 2.9+/-0.1% (dE/E = 6.8+/-0.3 % in FWHM) at the Qbb ~ 3 MeV region,
respectively. The multi-layer plastic-scintillator structure with good energy
resolution as well as good background suppression of beta-gamma rays is crucial
for the MOON-type detector to achieve the inverted hierarchy neutrino mass
sensitivity.Comment: 8 pages, 16 figures, submitted to Nucl.Instrum.Met
Prorenin anno 2008
For many years, prorenin has been considered to be nothing more than the inactive precursor of renin. Yet, its elevated levels in diabetic subjects with microvascular complications and its extrarenal production at various sites in the body suggest otherwise. This review discusses the origin, regulation, and enzymatic activity of prorenin, its role during renin inhibition, and the angiotensin-dependent and angiotensin-independent consequences of its binding to the recently discovered (pro)renin receptor. The review ends with the concept that prorenin rather than renin determines tissue angiotensin generation
Higher plasma prorenin concentration plays a role in the development of coronary artery disease
Radiative recombination of bare Bi83+: Experiment versus theory
Electron-ion recombination of completely stripped Bi83+ was investigated at
the Experimental Storage Ring (ESR) of the GSI in Darmstadt. It was the first
experiment of this kind with a bare ion heavier than argon. Absolute
recombination rate coefficients have been measured for relative energies
between ions and electrons from 0 up to about 125 eV. In the energy range from
15 meV to 125 eV a very good agreement is found between the experimental result
and theory for radiative recombination (RR). However, below 15 meV the
experimental rate increasingly exceeds the RR calculation and at Erel = 0 eV it
is a factor of 5.2 above the expected value. For further investigation of this
enhancement phenomenon the electron density in the interaction region was set
to 1.6E6/cm3, 3.2E6/cm3 and 4.7E6/cm3. This variation had no significant
influence on the recombination rate. An additional variation of the magnetic
guiding field of the electrons from 70 mT to 150 mT in steps of 1 mT resulted
in periodic oscillations of the rate which are accompanied by considerable
changes of the transverse electron temperature.Comment: 12 pages, 14 figures, to be published in Phys. Rev. A, see also
http://www.gsi.de/ap/ and http://www.strz.uni-giessen.de/~k
Reaction mechanism and characteristics of T_{20} in d + ^3He backward elastic scattering at intermediate energies
For backward elastic scattering of deuterons by ^3He, cross sections \sigma
and tensor analyzing power T_{20} are measured at E_d=140-270 MeV. The data are
analyzed by the PWIA and by the general formula which includes virtual
excitations of other channels, with the assumption of the proton transfer from
^3He to the deuteron. Using ^3He wave functions calculated by the Faddeev
equation, the PWIA describes global features of the experimental data, while
the virtual excitation effects are important for quantitative fits to the
T_{20} data. Theoretical predictions on T_{20}, K_y^y (polarization transfer
coefficient) and C_{yy} (spin correlation coefficient) are provided up to GeV
energies.Comment: REVTEX+epsfig, 17 pages including 6 eps figs, to be published in
Phys. Rev.
- …