106 research outputs found
Second-Order Self-Consistent-Field Density-Matrix Renormalization Group
We present a matrix-product state (MPS)-based quadratically convergent
density-matrix renormalization group self-consistent-field (DMRG-SCF) approach.
Following a proposal by Werner and Knowles (JCP 82, 5053, (1985)), our DMRG-SCF
algorithm is based on a direct minimization of an energy expression which is
correct to second-order with respect to changes in the molecular orbital basis.
We exploit a simultaneous optimization of the MPS wave function and molecular
orbitals in order to achieve quadratic convergence. In contrast to previously
reported (augmented Hessian) Newton-Raphson and super-configuration-interaction
algorithms for DMRG-SCF, energy convergence beyond a quadratic scaling is
possible in our ansatz. Discarding the set of redundant active-active orbital
rotations, the DMRG-SCF energy converges typically within two to four cycles of
the self-consistent procedureComment: 40 pages, 5 figures, 3 table
The estimation of pork carcass primal cuts value based on backfat thickness
The aim of the present study was to determine the effect of pork carcass backfat thickness on the dissection efficiency of four primal cuts (ham, loin, shoulder, belly),including correlation coefficients. The research material consisted of 80 pork carcasses. Backfat thickness (mm) was measured on cold half-carcasses using a vernier caliper at 6 points: at the first cervical vertebra (atlas), over shoulder at the thickest point, on the back, at the beginning, center, end of the gluteus medius muscle (CI, CII, CIII). On the basis of the average backfat thickness, measurements from 6 points were separated into two experimental groups: I (<25 mm); II (â„25 mm).Detailed dissection of the elements was performed to define mass (g): total,intermuscular fat, bones and lean meat. The significant effect of fat thickness on intermuscular fat content regardless of the cut was noted. Correlations between the average backfat thickness of 6 points and the total weight of the four main elements were calculated. In addition, the correlation coefficients were compared between the dissection elements and the average backfat thickness of 6 and 5 points. Higher backfat thickness determined the increase in the total mass of loin, shoulder and belly. A statistically proven correlation was shown between the average backfat thickness and the total mass of the analysed elements (r=0.293). When comparing the correlation coefficients of a different number of measurements a specific tendency was observed. Positive correlation coefficients were slightly higher for an average of 5 points of backfat thickness and negative correlation coefficients were slightly higher for an average of 6 points. Statistical differences between groups were recorded at the same level for the same parameters (Pâ€0.001 and 0.01<Pâ€0.05).The average backfat thickness of 6 points can be used as an indicator of the amount and quality of pork carcass primal cuts, with no adverse effects compared to standard 5 points
New Approaches for ab initio Calculations of Molecules with Strong Electron Correlation
Reliable quantum chemical methods for the description of molecules with
dense-lying frontier orbitals are needed in the context of many chemical
compounds and reactions. Here, we review developments that led to our
newcomputational toolbo x which implements the quantum chemical density matrix
renormalization group in a second-generation algorithm. We present an overview
of the different components of this toolbox.Comment: 19 pages, 1 tabl
Zur Relevanz von Polar- und Meerespolitik:Ein Bericht zur GrĂŒndung der Themengruppe Polar- und Meerespolitik der Deutschen Vereinigung fĂŒr Politikwissenschaft
Knecht S, Menzel A, Humrich C. Zur Relevanz von Polar- und Meerespolitik. Ein Bericht zur GrĂŒndung der Themengruppe âPolar- und Meerespolitikâ der Deutschen Vereinigung fĂŒr Politikwissenschaft an der UniversitĂ€t Bielefeld vom 30. September bis 02. Oktober 2019. Zeitschrift fĂŒr AuĂen- und Sicherheitspolitik. 2020;13:89â94
The cusp effect in eta' --> eta pi pi decays
Strong final-state interactions create a pronounced cusp in eta' --> eta pi0
pi0 decays. We adapt and generalize the non-relativistic effective field theory
framework developed for the extraction of pi pi scattering lengths from K --> 3
pi decays to this case. The cusp effect is predicted to have an effect of more
than 8% on the decay spectrum below the pi+ pi- threshold.Comment: 11 pages, 8 figures; comment added, typos corrected, version
published in Eur. Phys. J.
A disintegrin derivative as a case study for PHIP labeling of disulfide bridged biomolecules
A specific labeling strategy for bioactive molecules is presented for eptifibatide (integrilin) an antiplatelet aggregation inhibitor, which derives from the disintegrin protein barbourin in the venom of certain rattlesnakes. By specifically labeling the disulfide bridge this molecule becomes accessible for the nuclear spin hyperpolarization method of parahydrogen induced polarization (PHIP). The PHIP-label was synthesized and inserted into the disulfide bridge of eptifibatide via reduction of the peptide and insertion by a double Michael addition under physiological conditions. This procedure is universally applicable for disulfide-containing biomolecules and preserves their tertiary structure with a minimum of change. HPLC and MS spectra prove the successful insertion of the label. 1H-PHIP-NMR experiments yield a factor of over 1000 as lower limit for the enhancement factor. These results demonstrate the high potential of the labeling strategy for the introduction of site selective PHIP-labels into biomoleculesâ disulfide bonds
Selective inactivation of hypomethylating agents by SAMHD1 provides a rationale for therapeutic stratification in AML.
Hypomethylating agents decitabine and azacytidine are regarded as interchangeable in the treatment of acute myeloid leukemia (AML). However, their mechanisms of action remain incompletely understood, and predictive biomarkers for HMA efficacy are lacking. Here, we show that the bioactive metabolite decitabine triphosphate, but not azacytidine triphosphate, functions as activator and substrate of the triphosphohydrolase SAMHD1 and is subject to SAMHD1-mediated inactivation. Retrospective immunohistochemical analysis of bone marrow specimens from AML patients at diagnosis revealed that SAMHD1 expression in leukemic cells inversely correlates with clinical response to decitabine, but not to azacytidine. SAMHD1 ablation increases the antileukemic activity of decitabine in AML cell lines, primary leukemic blasts, and xenograft models. AML cells acquire resistance to decitabine partly by SAMHD1 up-regulation. Together, our data suggest that SAMHD1 is a biomarker for the stratified use of hypomethylating agents in AML patients and a potential target for the treatment of decitabine-resistant leukemia
Buiding in Dubai and Abu Dhabi - Field excursion of the faculty of civil engineering of the HTWG Konstanz 2009
Die 1,8-Millionenstadt Dubai und die Vereinigten Arabischen Emirate sind eine der Regionen der Welt mit den gröĂten BauaktivitĂ€ten. Der Exkursionsbericht schildert die EindrĂŒcke bei der Exkursion der FakultĂ€t Bauingenieurwesen der HTWG Konstanz im MĂ€rz 2009. Auf dem Programm standen die Baustellen der kĂŒnstlichen Palmeninsel "Palm Jebel Ali", des "Iris Bay"-Turms mit seiner auĂergewöhnlichen Architektur sowie des "Latifa Tower", einem "normalen" Hochhaus von 255 Meter Höhe. Geotechnik im WĂŒstensand unter der Leitung deutscher Firmen waren ebenso zu sehen wie der Bau des weltweit gröĂten Trinkwasserreservoirs. Weitere Höhepunkte der Reise waren die Baustellen des "Khalifa National Stadium" und der 1455 Meter langen Saadiyat-BrĂŒcke in Abu Dhabi, die die zukĂŒnftige Kulturmeile Abu Dhabis auf der Saadiyat Insel mit dem Festland verbinden wird.Dubai and the United Arab Emirates (UAE) are one of the regions in the world with the greatest building activities. The report depicts the impressions during a student field excursion of the Faculty of Civil Engineering of the University of Applied Sciences Konstanz, Germany, in March 2009
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