Signaling pathways for transduction of the initial message of the glycocode into cellular responses

The sugar units of glycan structures store information and establish an alphabet of life. The language of the oligosaccharide coding units is deciphered by receptors such as lectins and the decoded message can be transduced by multiple signaling pathways. Similar to glycoconjugates, these receptors can exhibit pronounced changes in quantitative and qualitative aspects of expression, as attested by a wealth of lectin and immunohistochemical studies. Since histochemistry provides a static picture, it is essential to shed light on the mechanisms of how a recognitive protein-carbohydrate interplay can be transduced into cellular responses. Their consequences for example for cell morphology will then be visible to the histochemist. Therefore, basic signaling routes will be graphically outlined and their trigger potential will be explained by selected examples from the realm of glycosciences

Capecitabine as second-line treatment for metastatic cholangiocarcinoma: A report of two cases

Background: The management of recurrent, metastatic cholangiocarcinoma still remains a problem since this tumor entity is classified as chemotherapy-resistant. When advanced or metastatic disease is diagnosed, the therapeutic efforts are essentially directed toward palliation. Patients and Methods: We report on 2 patients suffering from metastatic cholangiocarcinoma. Both had received previous chemotherapy for metastatic disease, including hepatic artery infusion {[}5-fluorouracil (5-FU)/folinic acid (FA) and oxaliplatin] and a combination therapy consisting of 5-FU/FA and gemcitabine. Since a progression of the disease was diagnosed, both patients were started on oral capecitabine at a daily dose of 2,500 mg/m(2) in 2 divided doses for 2 weeks, followed by 1 week rest. Results: Capecitabine was tolerated well and severe side effects were not observed. A stop of progression, documented by imaging procedures and tumor marker kinetics, was achieved in both patients. Conclusion: Capecitabine could potentially be used for second-line treatment in patients with progressive metastatic cholangiocarcinoma

Predicting race performance in triathlon: The role of perfectionism, achievement goals, and personal goal setting

The question of how perfectionism affects performance is highly debated. Because empirical studies examining perfectionism and competitive sport performance are missing, the present research investigated how perfectionism affected race performance and what role athletes’ goals played in this relationship in two prospective studies with competitive triathletes (Study 1: N = 112; Study 2: N = 321). Regression analyses showed that perfectionistic personal standards, high performance-approach goals, low performance-avoidance goals, and high personal goals predicted race performance beyond athletes’ performance level. Moreover, the contrast between performance-avoidance and performance-approach goals mediated the relationship between perfectionistic personal standards and performance, whereas personal goal setting mediated the relationship between performance-approach goals and performance. The findings indicate that perfectionistic personal standards do not undermine competitive performance, but are associated with goals that help athletes achieve their best possible performance

Fano blockade by a Bose-Einstein condensate in an optical lattice

We study the transport of atoms across a localized Bose-Einstein condensate in a one-dimensional optical lattice. For atoms scattering off the condensate we predict total reflection as well as full transmission for certain parameter values on the basis of an exactly solvable model. The findings of analytical and numerical calculations are interpreted by a tunable Fano-like resonance and may lead to interesting applications for blocking and filtering atom beams.Comment: 4 pages, 4 figures (fig4 was resized for arXiv

Neural networks for impact parameter determination

Accurate impact parameter determination in a heavy-ion collision is crucial for almost all further analysis. We investigate the capabilities of an artificial neural network in that respect. First results show that the neural network is capable of improving the accuracy of the impact parameter determination based on observables such as the flow angle, the average directed inplane transverse momentum and the difference between transverse and longitudinal momenta. However, further investigations are necessary to discover the full potential of the neural network approach

Quantum state transfer in disordered spin chains: How much engineering is reasonable?

The transmission of quantum states through spin chains is an important element in the implementation of quantum information technologies. Speed and fidelity of transfer are the main objectives which have to be achieved by the devices even in the presence of imperfections which are unavoidable in any manufacturing process. To reach these goals, several kinds of spin chains have been suggested, which differ in the degree of fine-tuning, or engineering, of the system parameters. In this work we present a systematic study of two important classes of such chains. In one class only the spin couplings at the ends of the chain have to be adjusted to a value different from the bulk coupling constant, while in the other class every coupling has to have a specific value. We demonstrate that configurations from the two different classes may perform similarly when subjected to the same kind of disorder in spite of the large difference in the engineering effort necessary to prepare the system. We identify the system features responsible for these similarities and we perform a detailed study of the transfer fidelity as a function of chain length and disorder strength, yielding empirical scaling laws for the fidelity which are similar for all kinds of chain and all disorder models. These results are helpful in identifying the optimal spin chain for a given quantum information transfer task. In particular, they help in judging whether it is worthwhile to engineer all couplings in the chain as compared to adjusting only the boundary couplings.Comment: 20 pages, 13 figures. Revised version, title changed, accepted by Quantum Information & Computatio

Parabolic equations with dynamical boundary conditions and source terms on interfaces

We consider parabolic equations with mixed boundary conditions and domain inhomogeneities supported on a lower dimensional hypersurface, enforcing a jump in the conormal derivative. Only minimal regularity assumptions on the domain and the coefficients are imposed. It is shown that the corresponding linear operator enjoys maximal parabolic regularity in a suitable $L^p$-setting. The linear results suffice to treat also the corresponding nondegenerate quasilinear problems.Comment: 30 pages. Revised version. To appear in Annali di Matematica Pura ed Applicat