University of Cologne

About: University of Cologne is a education organization based out in Cologne, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 32050 authors who have published 66350 publications receiving 2210092 citations. The organization is also known as: Universität zu Köln & Universitatis Coloniensis.

Cyberbullying: who are the victims? A comparison of victimization in internet chatrooms and victimization in school

Abstract: Bullying is not a phenomenon exclusive to the school environment. Pupils also become victims of verbal aggression (teasing, threats, insults, or harassment) in the context of internet chatrooms. The present study addresses the following questions: (1) How often does bullying occur in internet chatrooms? (2) Who are the victims of bullying in internet chatrooms? (3) What are the determinants of victimization in internet chatrooms? A total of 1700 pupils from various German secondary schools participated in the study. Results revealed a strong relationship between victimization in school and victimization in internet chatrooms; school victims are significantly more often chat victims. Furthermore, the predictors of chat and school victimization show both commonalities (gender, self-concept, child-parent relationship) and differences (social integration, popularity, and bullying behavior).

Energy-consistent pseudopotentials for quantum Monte Carlo calculations

Abstract: The authors present scalar-relativistic energy-consistent Hartree-Fock pseudopotentials for the main-group elements. The pseudopotentials do not exhibit a singularity at the nucleus and are therefore suitable for quantum Monte Carlo (QMC) calculations. They demonstrate their transferability through extensive benchmark calculations of atomic excitation spectra as well as molecular properties. In particular, they compute the vibrational frequencies and binding energies of 26 first- and second-row diatomic molecules using post-Hartree-Fock methods, finding excellent agreement with the corresponding all-electron values. They also show their pseudopotentials give superior accuracy than other existing pseudopotentials constructed specifically for QMC. Finally, valence basis sets of different sizes (VnZ with n=D,T,Q,5 for first and second rows, and n=D,T for third to fifth rows) optimized for our pseudopotentials are also presented.

Impaired glycosylation and cutis laxa caused by mutations in the vesicular H+-ATPase subunit ATP6V0A2.

Abstract: We identified loss-of-function mutations in ATP6V0A2, encoding the a2 subunit of the V-type H+ ATPase, in several families with autosomal recessive cutis laxa type II or wrinkly skin syndrome. The mutations result in abnormal glycosylation of serum proteins (CDG-II) and cause an impairment of Golgi trafficking in fibroblasts from affected individuals. These results indicate that the a2 subunit of the proton pump has an important role in Golgi function.

Towards a realistic microscopic description of highway traffic

Abstract: Simple cellular automata models are able to reproduce the basic properties of highway traffic. The comparison with empirical data for microscopic quantities requires a more detailed description of the elementary dynamics. Based on existing cellular automata models, we propose an improved discrete model incorporating anticipation effects, reduced acceleration capabilities and an enhanced interaction horizon for braking. The modified model is able to reproduce the three phases (free-flow, synchronized, and stop-and-go) observed in real traffic. Furthermore we find a good agreement with detailed empirical single-vehicle data in all phases.

Histone Deacetylase 8 in Neuroblastoma Tumorigenesis

Abstract: Purpose: The effects of pan–histone deacetylase (HDAC) inhibitors on cancer cells have shown that HDACs are involved in fundamental tumor biological processes such as cell cycle control, differentiation, and apoptosis However, because of the unselective nature of these compounds, little is known about the contribution of individual HDAC family members to tumorigenesis and progression The purpose of this study was to evaluate the role of individual HDACs in neuroblastoma tumorigenesis Experimental Design: We have investigated the mRNA expression of all HDAC1-11 family members in a large cohort of primary neuroblastoma samples covering the full spectrum of the disease HDACs associated with disease stage and survival were subsequently functionally evaluated in cell culture models Results: Only HDAC8 expression was significantly correlated with advanced disease and metastasis and down-regulated in stage 4S neuroblastoma associated with spontaneous regression High HDAC8 expression was associated with poor prognostic markers and poor overall and event-free survival The knockdown of HDAC8 resulted in the inhibition of proliferation, reduced clonogenic growth, cell cycle arrest, and differentiation in cultured neuroblastoma cells The treatment of neuroblastoma cell lines as well as short-term-culture neuroblastoma cells with an HDAC8-selective small-molecule inhibitor inhibited cell proliferation and clone formation, induced differentiation, and thus reproduced the HDAC8 knockdown phenotype Global histone 4 acetylation was not affected by HDAC8 knockdown or by selective inhibitor treatment Conclusions: Our data point toward an important role of HDAC8 in neuroblastoma pathogenesis and identify this HDAC family member as a specific drug target for the differentiation therapy of neuroblastoma