A new vibrational level of the H2+_2^+ molecular ion

A new state of the H$_2^+$ molecular ion with binding energy of 1.09$\times10^{-9}$ a.u. below the first dissociation limit is predicted, using highly accurate numerical nonrelativistic quantum calculations. It is the first L=0 excited state, antisymmetric with respect to the exchange of the two protons. It manifests itself as a huge p-H scattering length of $a=750\pm 5$ Bohr radii.Comment: 6 pages + 3 figure

Antiproton-Hydrogen annihilation at sub-kelvin temperatures

The main properties of the interaction of ultra low-energy antiprotons ($E\le10^{-6}$ a.u.) with atomic hydrogen are established. They include the elastic and inelastic cross sections and Protonium (Pn) formation spectrum. The inverse Auger process ($Pn+e \to H+\bar{p}$) is taken into account in the framework of an unitary coupled-channels model. The annihilation cross-section is found to be several times smaller than the predictions made by the black sphere absorption models. A family of $\bar{p}H$ nearthreshold metastable states is predicited. The dependence of Protonium formation probability on the position of such nearthreshold S-matrix singularities is analysed. An estimation for the $H\bar{H}$ annihilation cross section is obtained.Comment: latex.tar.gz file, 22 pages, 9 figure

Benchmark calculation of n-3H and p-3He scattering

The n-3H and p-3He elastic phase-shifts below the trinucleon disintegration thresholds are calculated by solving the 4-nucleon problem with three different realistic nucleon-nucleon interactions (the I-N3LO model by Entem and Machleidt, the Argonne v18 potential model, and a low-k model derived from the CD-Bonn potential). Three different methods -- Alt, Grassberger and Sandhas, Hyperspherical Harmonics, and Faddeev-Yakubovsky -- have been used and their respective results are compared. For both n-3H and p-3He we observe a rather good agreement between the three different theoretical methods. We also compare the theoretical predictions with the available experimental data, confirming the large underprediction of the p-3He analyzing power.Comment: 18 pages, 9 figure

PLA films with improved flexibility properties by using maleinized cottonseed oil

[EN] This work assesses the potential of maleinized cottonseed oil MCSO as plasticizer in poly(lactic acid) PLA films with improved ductile behaviour. The effects of MCSO are compared with commercially available maleinized oil, i.e. maleinized linseed oil MLO in terms of mechanical, thermal and barrier properties, as well as morphology changes. Plasticized PLA formulations were obtained with a maleinized oil content in the 0 10 wt% range. Addition of both maleinized vegetable oils leads to a slight decrease in the glass transition temperature (Tg) of neat PLA from 63 °C to 60 61 °C. Nevertheless, MCSO provides better overall properties. Addition of 7.5 wt% MCSO increases the elongation at break by 292%. Regarding the barrier properties, both maleinized vegetable oils increase the oxygen transmission rate OTR. Nevertheless, this increase is less pronounced in the case of MCSO thus indicating its higher efficiency compared to MLO. On the other hand, addition of both maleinized vegetable oils do not compromise the overall disintegration of the obtained PLA formulations, thus positioning these additives as environmentally friendly solutions to increase ductile properties in PLA-based films.This research was supported by the Ministry of Economy and Competitiveness - MINECO, Ref: MAT2014-59242-C2-1-R. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant. Garcia-Garcia wants to thanks the Spanish Ministry of Education, Culture and Sports for their financial support through an FPU grant (FPU13/06011).Carbonell-Verdu, A.; Garcia-Garcia, D.; Dominici, F.; Torre, L.; Sanchez-Nacher, L.; Balart, R. (2017). PLA films with improved flexibility properties by using maleinized cottonseed oil. European Polymer Journal. 91:248-259. https://doi.org/10.1016/j.eurpolymj.2017.04.013S2482599

Ribozyme-mediated compensatory induction of menin-oncosuppressor function in primary fibroblasts from MEN1 patients

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The Nuclear Yukawa Model on a Lattice

We present the results of the quantum field theory approach to nuclear Yukawa model obtained by standard lattice techniques. We have considered the simplest case of two identical fermions interacting via a scalar meson exchange. Calculations have been performed using Wilson fermions in the quenched approximation. We found the existence of a critical coupling constant above which the model cannot be numerically solved. The range of the accessible coupling constants is below the threshold value for producing two-body bound states. Two-body scattering lengths have been obtained and compared to the non relativistic results.Comment: 15 page

Manufacturing and compatibilization of PLA/PBAT binary blends by cottonseed oil-based derivatives

[EN] This research work aims at the compatibilization of poly(lactic acid)/poly(butylene adipate-co-terephthalate), PLA/PBAT binary blends by using cottonseed oil derivatives, i.e. epoxidized (ECSO) and maleinized (MCSO) cottonseed oil. The potential of these vegetable oil-based compatibilizers are compared versus the effects of a conventional styrene-acrylic oligomer. The base PLA/PBAT binary blend composition was 80 wt% PLA/20 wt% PBAT and the amount of compatibilizer was set to 1 and 7.5 wt%. The effects of the different compatibilizers were evaluated on PLA/PBAT films in terms of mechanical and thermal properties as well as blend's morphology by field emission scanning electron microscopy (FESEM). Complementary, biodisintegration tests in controlled compost soil and surface properties were evaluated to assess the effects of the compatibilizers. Addition of 1 wt% ECSO and MCSO led to a remarkable increase in the elongation at break up to values over 100% with regard to neat PLA. Despite this, maximum elongation at break was obtained for the compatibilized PLA/PBAT blend with 7.5 wt% MCSO, reaching values of about 321.2% respect neat PLA keeping mechanical resistant properties, such as Young's modulus and tensile strength, at high levels. Therefore, vegetable oil-derived compatibilizers stand out as environmentally friendly additives for PLA/PBAT binary blends with improved properties.This work was supported by the Ministry of Economy and Competitiveness (MINECO) (grant number MAT2017-84909-C2-2-R). A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant.Carbonell-Verdu, A.; Ferri, J.; Dominici, F.; Boronat, T.; Sanchez-Nacher, L.; Balart, R.; Torre, L. (2018). Manufacturing and compatibilization of PLA/PBAT binary blends by cottonseed oil-based derivatives. eXPRESS Polymer Letters. 12(9):808-823. https://doi.org/10.3144/expresspolymlett.2018.69S80882312

Point-Form Analysis of Elastic Deuteron Form Factors

Point-form relativistic quantum mechanics is applied to elastic electron-deuteron scattering. The deuteron is modeled using relativistic interactions that are scattering-equivalent to the nonrelativistic Argonne $v_{18}$ and Reid '93 interactions. A point-form spectator approximation (PFSA) is introduced to define a conserved covariant current in terms of single-nucleon form factors. The PFSA is shown to provide an accurate description of data up to momentum transfers of 0.5 ${\rm GeV}^2$, but falls below the data at higher momentum transfers. Results are sensitive to the nucleon form factor parameterization chosen, particularly to the neutron electric form factor.Comment: RevTex, 31 pages, 1 table, 13 figure

Mycobacterial aminoglycoside acetyltransferases: a little of drug resistance, and a lot of other roles

Aminoglycoside acetyltransferases are important determinants of resistance to aminoglycoside antibiotics in most bacterial genera. In mycobacteria, however, aminoglycoside acetyltransferases contribute only partially to aminoglycoside susceptibility since they are related with low level resistance to these antibiotics (while high level aminoglycoside resistance is due to mutations in the ribosome). Instead, aminoglycoside acetyltransferases contribute to other bacterial functions, and this can explain its widespread presence along species of genus Mycobacterium. This review is focused on two mycobacterial aminoglycoside acetyltransferase enzymes. First, the aminoglycoside 2'-N-acetyltransferase [AAC(2')], which was identified as a determinant of weak aminoglycoside resistance in M. fortuitum, and later found to be widespread in most mycobacterial species; AAC(2') enzymes have been associated with resistance to cell wall degradative enzymes, and bactericidal mode of action of aminoglycosides. Second, the Eis aminoglycoside acetyltransferase, which was identified originally as a virulence determinant in M. tuberculosis (enhanced intracellular survival); Eis protein in fact controls production of pro-inflammatory cytokines and other pathways. The relation of Eis with aminoglycoside susceptibility was found after the years, and reaches clinical significance only in M. tuberculosis isolates resistant to the second-line drug kanamycin. Given the role of AAC(2') and Eis proteins in mycobacterial biology, inhibitory molecules have been identified, more abundantly in case of Eis. In conclusion, AAC(2') and Eis have evolved from a marginal role as potential drug resistance mechanisms into a promising future as drug targets

Finding polynomial loop invariants for probabilistic programs

Quantitative loop invariants are an essential element in the verification of probabilistic programs. Recently, multivariate Lagrange interpolation has been applied to synthesizing polynomial invariants. In this paper, we propose an alternative approach. First, we fix a polynomial template as a candidate of a loop invariant. Using Stengle's Positivstellensatz and a transformation to a sum-of-squares problem, we find sufficient conditions on the coefficients. Then, we solve a semidefinite programming feasibility problem to synthesize the loop invariants. If the semidefinite program is unfeasible, we backtrack after increasing the degree of the template. Our approach is semi-complete in the sense that it will always lead us to a feasible solution if one exists and numerical errors are small. Experimental results show the efficiency of our approach.Comment: accompanies an ATVA 2017 submissio