Sensing the Spin of an Individual Ce Adatom Ternes, Markus; Lutz, Christopher P; Heinrich, Andreas J ...
Physical review letters,
04/2020, Letnik:
124, Številka:
16
Journal Article
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The magnetic moment of rare earth elements originates from electrons in the partially filled 4f orbitals. Accessing this moment electrically by scanning tunneling spectroscopy is hampered by ...shielding of outerlying orbitals. Here, we show that we can detect the magnetic moment of an individual Ce atom adsorbed on a Cu_{2}N ultrathin film on Cu(100) by using a sensor tip that has its apex functionalized with a Kondo screened spin system. We calibrate the sensor tip by deliberately coupling it to a well characterized Fe atom. Subsequently, we use the splitting of the tip's Kondo resonance when approaching a spectroscopically dark Ce atom to sense its magnetic moment.
Three's company: Rhizopodin is a cytostatic macrolide and a potent actin depolymerizer produced by the myxobacterium Myxococcus stipitatus. A crystal structure analysis of the rhizopodin/actin ...complex reveals that rhizopodin is a C2‐symmetric bislactone (see formula). The ternary complex supports the mode of rhizopodin‐induced actin dimerization and reveals the absolute configuration and biologically active conformation of this macrolide.
The Middle Pleistocene site Bilzingsleben II is well-known for its wealth of vertebrate and archaeological remains. Of particular importance is the record of Homo erectus bilzingslebenensis. Most ...palaeontologists consider the find horizon as a primary vertebrate deposit formed during human occupation, while some archaeologists attribute its formation to turbulent gravitational mass flows, inundation or a combination of both. Here we present mortality profiles of the beavers Castor and Trogontherium to provide further arguments to this controversial discussion. The mortality profiles of Castor from Bilzingsleben II, Weimar-Ehringsdorf and Weimar-Taubach are largely identical indicating similar taphonomic filters that were effective in the formation of the find layers. Individuals, which were tentatively classified as suspected ±2–2½ year old beavers dominate by far in all three sites. The structure of these mortality profiles shows similarities to Stiner’s (1990) “prime dominated mortality pattern”, which is indicative of human hunting. This consideration is supported by the difference of the mortality profile of Trogontherium from Bilzingsleben II (dominance of older individuals) in relation to the profiles of non-hominin generated assemblages of Tegelen and Mosbach 2 (dominance of younger individuals). Thus, our data support the interpretation of the Palaeolithic find horizon of Bilzingsleben II as a primary vertebrate deposit, but not the gravitational mass flow and inundation hypotheses.
The region around Tendaguru Hill in southeastern Tanzania has provided a rich, Late Jurassic dinosaur fauna. Among them, thousands of bones of the basal iguanodontian ornithopod Dysalotosaurus ...lettowvorbecki have been excavated in the Ig/WJ-quarry northwest of the Tendaguru Hill. The incomplete record of the taphonomic information from the excavation is the main reason for the still inconclusive interpretation of the assemblage as either catastrophic or attritional in origin. In this study, all available historical notes, sketches and field catalogues were analysed and combined with data from CT scans, new taphonomic observations and from bone histological as well as demographic analyses. According to these combined results, the mass accumulation of remains of D. lettowvorbecki consists of four closely associated bonebeds in at least three different stratigraphic levels. The bonebeds are classified as mixed, multitaxic, and monodominant. There is no evidence of abrasion and preburial weathering on the bones suggesting minimal transport distances and duration as well as short preburial exposure times. Although the size/age distributions are bimodally U-shaped, the bonebeds are interpreted as catastrophic in origin due to the restricted spatial extent and the overall uniform preservation of the bones. It is proposed that different herds of D. lettowvorbecki crossed a tidal channel several times during seasonal migration and that each time several to dozens of individuals died. The bodies decomposed and were buried at a barrier or a bend nearby. The demographic conditions as well as the modes of death and burial of D. lettowvorbecki are very similar to the observations made from the modern blue wildebeest in the Masai-Mara Reserve in Kenya. Key words: Dinosauria, Dysalotosaurus lettowvorbecki, history, demography, taphonomy, Jurassic, Tendaguru, Africa.
We analyzed the prevalence, clinical pattern, and prognostic impact of CNS involvement in a large cohort of children and adolescents diagnosed with non-Hodgkin's lymphoma (NHL), with special ...attention to differences according to NHL subtype.
From October 1986 to December 2002, 2,381 patients (median age, 9.37 years; range, 0.2 to 23.8 years; female-to-male ratio, 1:2.7) from Germany, Austria, and Switzerland were registered. A total of 2,086 patients were eligible for the consecutive multicenter protocols NHL-Berlin-Frankfurt-Münster BFM -86, NHL-BFM-90, and NHL-BFM-95, and could be evaluated for outcome.
CNS involvement was diagnosed in 141 (5.9%) of 2,381 patients and was associated with an advanced stage of NHL. The percentage of CNS-positive patients was 8.8% for Burkitt's lymphoma/Burkitt's leukemia (BL/B-ALL), 5.4% for precursor B-lymphoblastic lymphoma (pB-LBL), 3.3% for anaplastic large-cell lymphoma, 3.2% for T-cell-LBL, 2.6% for diffuse large B-cell lymphoma, and 0% for primary mediastinal large B-cell NHL (P < .001). Most CNS-positive patients with pB-LBL, T-LBL, or BL/B-ALL had meningeal disease. The probability of event-free survival (pEFS; +/- SE) at 5 years was 85% +/- 1% for the 2,086 protocol patients (median follow-up, 6.5 years; range, 0.3 to 17.7 years). For the 112 CNS-positive patients, pEFS was 64% +/- 5%, compared with 86% +/- 1% for the 1,927 CNS-negative patients (P < .001). Although CNS disease had no impact on pEFS for advanced-stage T-LBL patients, CNS-positive patients with BL/B-ALL had a worse average outcome than CNS-negative patients with stage IV BL/B-ALL (60% +/- 5% v 81% +/- 3%; P < .001). In multivariate analysis, CNS disease was the strongest predictor for relapse in BL/B-ALL patients with advanced-stage disease.
Six percent of childhood/adolescent NHL patients were CNS positive. However, the prevalence, pattern, and prognostic impact of CNS involvement differed among NHL subtypes.
Rhizopodin was isolated as cytostatic and weakly antifungal macrolide (
1) and later characterized as potent actin-depolymerizing agent. It is produced by the myxobacterium
Myxococcus stipitatus, ...which enables a fermentative supply of the drug for biological studies. We here report a revised structure that characterizes rhizopodin (
2) as the first known dimeric bis-lactone exhibiting side chains that terminate in
N-methyl-vinylformamide groups, which are otherwise found in smaller marine toxins also targeting the actin cytoskeleton. Compound
2 might function as bivalent inhibitor forming ternary complexes with actin which would explain its high efficacy.
The tribe Microtoscoptini, comprising the genera
from Eurasia and
and
from North America, is an enigmatic group of microtoid cricetids, which was widespread during the Late Miocene. Although fossil ...remains have been reported from 33 localities, their evolutionary and dispersal history is still poorly understood.
Here we give an overview of sites and records and discuss temporal ranges and some aspects of the dispersal history. The branch of cricetids that gave rise to the Microtoscoptini is still unknown. The currently oldest records are those of
from Shala in China, considered 8 to 9 Ma and correlated with MN 10 or MN 11. All other remains from Eurasia are distinctly younger (MN 11 – MN 13). The earliest North American records of
and
are from the early Hemphillian beginning at 9.0 Ma (approximately MN 10 – MN 11 transition). Whether
from Shala actually indicates the origin of Microtoscoptini in Asia and subsequent dispersal to North America is still unclear. The presence of Microtoscoptini in both Central Asia and North America during the Late Miocene does suggest dispersal through Beringia. The Microtoscoptini inhabited probably open grasslands locally differentiated by shrubs, tree patches and water bodies. It is far from clear why the Microtoscoptini became extinct even though they had developed an efficient arvicoline-like cheek-tooth pattern.
Neuroimaging plays a significant role in the diagnosis of intracranial tumors, especially brain gliomas, and must consist of an assessment of location and extent of the tumor and of its biologic ...activity. Therefore, morphologic imaging modalities and functional, metabolic, or molecular imaging modalities should be combined for primary diagnosis and for following the course and evaluating therapeutic effects. MRI is the gold standard for providing detailed morphologic information and can supply some additional insights into metabolism (MR spectroscopy) and perfusion (perfusion-weighted imaging) but still has limitations in identifying tumor grade, invasive growth into neighboring tissue, and treatment-induced changes, as well as recurrences. These insights can be obtained by various PET modalities, including imaging of glucose metabolism, amino acid uptake, nucleoside uptake, and hypoxia. Diagnostic accuracy can benefit from coregistration of PET results and MRI, combining the high-resolution morphologic images with the biologic information. These procedures are optimized by the newly developed combination of PET and MRI modalities, permitting the simultaneous assessment of morphologic, functional, metabolic, and molecular information on the human brain.
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