1,144 research outputs found
New results for the fully renormalized proton-neutron quasiparticle random phase approximation
A many-body Hamiltonian describing a system of Z protons and N neutrons
moving in spherical shell model mean field and interacting among themselves
through proton-proton and neutron-neutron pairing and a dipole-dipole
proton-neutron interaction of both particle-hole and particle-particle type, is
treated within a fully renormalized (FR) pnQRPA approach. Two decoupling
schemes are formulated. One of them decouples the equations of motion of
particle total number conserving and non-conserving operators. One ends up with
two very simple dispersion equations for phonon operators which are formally of
Tamm-Dancoff types. For excitations in the (N-1,Z+1) system, Ikeda sum rule is
fully satisfied provided the BCS equations are renormalized as well and
therefore solved at a time with the FRpnQRPA equations. Next, one constructs
two operators , which
commutes with the particle total number conserving operators, and , and moreover could be
renormalized so that they become bosons. Then, a phonon operator is built up as
a linear combination of these four operators. The FRpnQRPA equations are
written down for this complex phonon operator and the ISR is calculated
analytically. This formalism allows for an unified description of the dipole
excitations in four neighboring nuclei (N-1,Z+1),(N+1,Z-1),(N-1,Z-1),(N+1,Z+1).
The phonon vacuum describes the (N,Z) system ground state.Comment: 24 page
The Effect of a Type I Photoinitiator on Cure Kinetics and Cell Toxicity in Projection-Microstereolithography
AbstractProjection-microstereolithography is an additive manufacturing technique based on the spatially controlled solidification of a liquid photopolymer on exposure to digitally manipulated light patterns. This study presents a methodology to evaluate the effect of a type-I photoinitiator on the reaction kinetics in the process and the cytocompatibility of the produced components. While the reaction speed and degree of conversion were heavily dependent on the applied amount of the initiator, a clear toxic effect was observed with all tested concentrations, and a post-processing step of 7 days was required to leach out the initiator residues
Genetic partitioning of interleukin-6 signalling in mice dissociates Stat3 from Smad3-mediated lung fibrosis
Idiopathic pulmonary fibrosis (IPF) is a fatal disease that is unresponsive to current therapies and characterized by excessive collagen deposition and subsequent fibrosis. While inflammatory cytokines, including interleukin (IL)-6, are elevated in IPF, the molecular mechanisms that underlie this disease are incompletely understood, although the development of fibrosis is believed to depend on canonical transforming growth factor (TGF)-β signalling. We examined bleomycin-induced inflammation and fibrosis in mice carrying a mutation in the shared IL-6 family receptor gp130. Using genetic complementation, we directly correlate the extent of IL-6-mediated, excessive Stat3 activity with inflammatory infiltrates in the lung and the severity of fibrosis in corresponding gp130757F mice. The extent of fibrosis was attenuated in B lymphocyte-deficient gp130757F;µMT−/− compound mutant mice, but fibrosis still occurred in their Smad3−/− counterparts consistent with the capacity of excessive Stat3 activity to induce collagen 1α1 gene transcription independently of canonical TGF-β/Smad3 signalling. These findings are of therapeutic relevance, since we confirmed abundant STAT3 activation in fibrotic lungs from IPF patients and showed that genetic reduction of Stat3 protected mice from bleomycin-induced lung fibrosis
First-principles extrapolation method for accurate CO adsorption energies on metal surfaces
We show that a simple first-principles correction based on the difference
between the singlet-triplet CO excitation energy values obtained by DFT and
high-level quantum chemistry methods yields accurate CO adsorption properties
on a variety of metal surfaces.
We demonstrate a linear relationship between the CO adsorption energy and the
CO singlet-triplet splitting, similar to the linear dependence of CO adsorption
energy on the energy of the CO 2* orbital found recently {[Kresse {\em et
al.}, Physical Review B {\bf 68}, 073401 (2003)]}. Converged DFT calculations
underestimate the CO singlet-triplet excitation energy ,
whereas coupled-cluster and CI calculations reproduce the experimental . The dependence of on is used
to extrapolate for the top, bridge and hollow sites for the
(100) and (111) surfaces of Pt, Rh, Pd and Cu to the values that correspond to
the coupled-cluster and CI value. The correction
reproduces experimental adsorption site preference for all cases and obtains
in excellent agreement with experimental results.Comment: Table sent as table1.eps. 3 figure
Gemcitabine-Based Neoadjuvant Treatment in Borderline Resectable Pancreatic Ductal Adenocarcinoma: A Meta-Analysis of Individual Patient Data
Background: Non-randomized studies have investigated multi-agent gemcitabinebased neo-adjuvant therapies (GEM-NAT) in borderline resectable pancreatic
ductal adenocarcinoma (BR-PDAC). Treatment sequencing and specific elements
of neoadjuvant treatment are still under investigation. The present meta-analysis aims to
assess the effectiveness of GEM-NAT on overall survival (OS) in BR-PDAC.
Patients and Methods: A meta-analysis of individual participant data (IPD) on GEMNAT for BR-PDAC were performed. The primary outcome was OS after treatment with
GEM-based chemotherapy. In the Individual Patient Data analysis data were reappraised
and confirmed as BR-PDAC on provided radiological data.
Results: Six studies investigating GEM-NAT were included in the IPD metanalysis.
The IPD metanalysis was conducted on 271 patients who received GEM-NAT.
Pooled median patient-level OS was 22.2 months (95%CI 19.1–25.2). R0 rates
ranged between 81 and 95% (I
2 = 0%, p = 0.64), respectively. Median OS was
27.8 months (95%CI 23.9–31.6) in the patients who received NAT-GEM followed
by resection compared to 15.4 months (95%CI 12.3–18.4) for NAT-GEM without
resection and 13.0 months (95%CI 7.4–18.5) in the group of patients who received
upfront surgery (p < 0.0001). R0 rates ranged between 81 and 95% (I
2 = 0%,
p = 0.64), respectively. Overall survival in the R0 group was 29.3 months (95%
CI 24.3–34.2) vs. 16.2 months (95% CI 7·9–24.5) in the R1 group (p = 0·001). Conclusions: The present study is the first meta-analysis combining IPD from a
number of international centers with BR-PDAC in a cohort that underwent multi-agent
gemcitabine neoadjuvant therapy (GEM-NAT) before surgery. GEM-NAT followed by
surgical resection improve sur
Fusion of secretory vesicles isolated from rat liver
Secretory vesicles isolated from rat liver were found to fuse after exposure to Ca2+. Vescle fusion is characterized by the occurrence of twinned vesicles with a continuous cleavage plane between two vesicles in freeze-fracture electron microscopy. The number of fused vesicles increases with increasing Ca2+-concentrations and is half maximal around 10–6 m. Other divalent cations (Ba2+, Sr2+, and Mg2+) were ineffective. Mg2+ inhibits Ca2+-induced fusion. Therefore, the fusion of secretory vesiclesin vitro is Ca2+ specific and exhibits properties similar to the exocytotic process of various secretory cells.
Various substances affecting secretionin vivo (microtubular inhibitors, local anethetics, ionophores) were tested for their effect on membrane fusion in our system.
The fusion of isolated secretory vesicles from liver was found to differ from that of pure phospholipid membranes in its temperature dependence, in its much lower requirement for Ca2+, and in its Ca2+-specificity. Chemical and enzymatic modifications of the vesicle membrane indicate that glycoproteins may account for these differences
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