University of Luxembourg

About: University of Luxembourg is a education organization based out in Luxembourg, Luxembourg. It is known for research contribution in the topics: Context (language use) & Computer science. The organization has 4744 authors who have published 22175 publications receiving 381824 citations.

Metallaxis-FL: mutation-based fault localization

Abstract: Fault localization methods seek to identify faulty program statements based on the information provided by the failing and passing test executions. Spectrum-based methods are among the most popular ones and assist programmers by assigning suspiciousness values on program statements according to their probability of being faulty. This paper proposes Metallaxis, a fault localization approach based on mutation analysis. The innovative part of Metallaxis is that it uses mutants and links them with the faulty program places. Thus, mutants that are killed mostly by failing tests provide a good indication about the location of a fault. Experimentation using Metallaxis suggests that it is significantly more effective than statement-based approaches. This is true even in the case where mutation cost-reduction techniques, such as mutant sampling, are facilitated. Additionally, results from a controlled experiment show that the use of mutation as a testing technique provides benefits to the fault localization process. Therefore, fault localization is significantly improved by using mutation-based tests instead of block-based or branch-based test suites. Finally, evidence in support of the methods' scalability is also given. Copyright © 2013 John Wiley & Sons, Ltd.

Raman analysis of monoclinic Cu2SnS3 thin films

Abstract: Secondary phases like Cu2SnS3 are major obstacles for kesterite thin film solar cell applications. We prepare Cu2SnS3 using identical annealing conditions as used for the kesterite films. By x-ray diffraction, the crystal structure of Cu2SnS3 was identified as monoclinic. Polarization-dependent Raman investigations allowed the identification of the dominant peaks at 290 cm−1 and 352 cm−1 with the main A′ symmetry vibrational modes from the monoclinic Cu2SnS3 phase. Furthermore, micro-resolved Raman investigations revealed local variations in the spectra that are attributed to a secondary phase (possibly Cu2Sn3S7). This exemplifies the abilities of micro-resolved Raman measurements in the detection of secondary phases.

Integrin alpha(v)beta3 expression confers on tumor cells a greater propensity to metastasize to bone

Abstract: The reasons why tumor cells metastasize to bone remain obscure. There is some evidence to support the theory that integrins (acting as cell surface adhesion receptors) play a role in mediating metastasis in certain organs. Here, we report that overexpression of a functionally active integrin alpha(v)b3 in Chinese hamster ovary (CHO) tumor cells drastically increased the incidence, number, and area of bone metastases in nude mice compared with those observed in mock-transfected CHO cells (CHO dhfr+) or in CHO cells expressing a functionally inactive integrin alpha(v)b3 (CHO beta3Delta744). Moreover, a breast cancer cell line (B02) established from bone metastases caused by MDA-MB-231 cells constitutively overexpressed integrin alpha(v)b3, whereas the cell surface expression level of other integrins remained unchanged. In vivo, the extent of bone metastases in B02-bearing mice was significantly increased compared with that of MDA-MB-231-bearing mice. In vitro, B02 cells and CHO cells expressing a functionally active integrin alpha(v)b3 exhibited substantially increased invasion of and adhesion to mineralized bone, bone sialoprotein, and collagen compared with those found with MDA-MB-231, CHO dhfr+, and CHO beta3Delta744 cells, respectively. Overall, our findings suggest that integrin alpha(v)b3 expression in tumor cells accelerates the development of osteolytic lesions, presumably through increased invasion of and adhesion to bone.