Finite size effects and magnetic order in the spin-1/2 honeycomb lattice compound InCu{2/3}V{1/3}O{3}

High field electron spin resonance, nuclear magnetic resonance and magnetization studies addressing the ground state of the quasi two-dimensional spin-1/2 honeycomb lattice compound InCu{2/3}V{1/3}O{3} are reported. Uncorrelated finite size structural domains occurring in the honeycomb planes are expected to inhibit long range magnetic order. Surprisingly, ESR data reveal the development of two collinear antiferromagnetic (AFM) sublattices below ~ 20 K whereas NMR results show the presence of the staggered internal field. Magnetization data evidence a spin reorientation transition at ~ 5.7 T. Quantum Monte-Carlo calculations show that switching on the coupling between the honeycomb spin planes in a finite size cluster yields a Neel-like AFM spin structure with a substantial staggered magnetization at finite temperatures. This may explain the occurrence of a robust AFM state in InCu{2/3}V{1/3}O{3} despite an unfavorable effect of structural disorder.Comment: revised version, accepted as a Rapid Communication in Phys. Rev. B (2010

Shock recovery experiments confirm the possibility of transferring viable microorganisms from Mars to Earth

Extract from introduction: With regard to the impact and ejection phase we tested the case for the transfer of microorganisms from Mars to Earth. Using a high explosive set-up thin layers of bacterial endospores of Bacillus subtilis, of the lichen Xanthoria elegans and of the cyanobacterium Chroococcidiopsis sp. embedded between two plates of gabbro were subjected to 10, 20, 30, 40 and 50 GPa which is the pressure range observed in Martian meteorites [1]

Life after shock: the mission from Mars to Earth

Extract from introduction: The minerals of the Martian meteorites collected so far indicate an exposure to shock waves in the pressure range of 5 to 55 GPa [1]. As terrestrial rocks are frequently inhabited by microbial communities, rocks ejected from a planet by impact processes may carry with them endolithic microorganisms, if microbial life existed/exists on this planet

Diagnosis of Burkitt's lymphoma in due time: a practical approach

Aims: The quick diagnosis of Burkitt's lymphoma (BL) and its clear-cut differentiation from diffuse large B-cell lymphoma (DLBCL) is of great clinical importance since treatment for these two disease entities differ markedly and should promptly be initiated in BL. However, these two tumours are difficult to distinguish using the current WHO classification, particularly in regard to BL variants, i.e., BL with plasmacytoid differentiation and atypical Burkitt's/Burkitt's-like lymphomas. Methods: We studied 39 cases of highly proliferative blastic B-cell lymphoma (HPBCL) to establish a practical differential-diagnostic algorithm. Characteristics set for BL were a typical morphology, a mature B-cell phenotype of CD10+, Bcl-6+ and Bcl-2- tumour cells, a proliferation rate of >95%, and the presence of C-MYC rearrangements in the absence of t(14;18)(q32;q21). All cases were selectively negative for cyclin D-1, CD5, CD23, LMP-EBV, CD34 and TdT, and there were no cases of endemic or immunodeficiency-associated Burkitt's lymphoma. Results: Altogether the set BL characteristics were found in only 5/39 cases (12.8%), whereas the majority of tumours revealed mosaic features (87.2%). In a second attempt, we followed a pragmatic stepwise approach for a classification algorithm that includes the assessment of C-MYC status to stratify HPBCL into four predefined diagnostic categories (DC), namely DC I (5/39, 12.8%): "classical BL", corresponding to the classical variant of sporadic BL in the WHO classification; DC II (11/39, 28.2%): "atypical BL", corresponding to the atypical Burkitt's/Burkitt's-like variants of sporadic BL in the WHO classification; DC III (9/39, 23.1%): "C-MYC+ DLBCL"; and DC IV (14/39, 35.9%): "C-MYC- HPBCL". Conclusion: This proposal may serve as a robust and objective operational basis for therapeutic decisions for HPBCL within one week and is applicable to be evaluated for its prognostic relevance in prospective clinical trials

Impact experiments in support of “Lithopanspermia”: The route from Mars to Earth

Shock recovery experiments on a Martian analogue rock (gabbro) loaded with three types of microorganisms reveal that these organisms survive the impact and ejection phase on Mars at shock pressures up to about 50 GPa with exponentially decreasing survival rates