189 research outputs found
The abundances of hydrocarbon functional groups in the interstellar medium inferred from laboratory spectra of hydrogenated and methylated polycyclic aromatic hydrocarbons
Infrared (IR) absorption spectra of individual polycyclic aromatic
hydrocarbons (PAHs) containing methyl (-CH3), methylene (>CH2), or diamond-like
*CH groups and IR spectra of mixtures of methylated and hydrogenated PAHs
prepared by gas phase condensation were measured at room temperature (as grains
in pellets) and at low temperature (isolated in Ne matrices). In addition, the
PAH blends were subjected to an in-depth molecular structure analysis by means
of high-performance liquid chromatography, nuclear magnetic resonance
spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight
mass spectrometry. Supported by calculations at the density functional theory
level, the laboratory results were applied to analyze in detail the aliphatic
absorption complex of the diffuse interstellar medium at 3.4 mu-m and to
determine the abundances of hydrocarbon functional groups. Assuming that the
PAHs are mainly locked in grains, aliphatic CHx groups (x = 1,2,3) would
contribute approximately in equal quantities to the 3.4 mu-m feature (N_{CHx} /
N_{H} approx 10^{-5} - 2 * 10^{-5}). The abundances, however, may be two to
four times lower if a major contribution to the 3.4 mu-m feature comes from
molecules in the gas phase. Aromatic =CH groups seem to be almost absent from
some lines of sight, but can be nearly as abundant as each of the aliphatic
components in other directions (N_{=CH} / N_{H} < 2 * 10^{-5}; upper value for
grains). Due to comparatively low binding energies, astronomical IR emission
sources do not display such heavy excess hydrogenation. At best, especially in
proto-planetary nebulae, >CH2 groups bound to aromatic molecules, i.e., excess
hydrogens on the molecular periphery only, can survive the presence of a nearby
star.Comment: 34 pages, 19 figures, ApJS, 208, 2
Oratio De Dvbio Felicitatis Mvndi Et Hominvm Incremento
http://tartu.ester.ee/record=b1215390~S1*es
Dialektik der Deprivation: Zu Idee und Praxis der Entsagung als Element des Autoritarismus und ihre Rekonfiguration in der Gegenwart:Gesellschaftstheoretische, psychologische und empirische Dimensionen und ihre Aktualität im Spiegel der Kritischen Theorie
As the recent growth of authoritarian movements shows, the more complex society becomes and the more certain groups react to their feelings of powerlessness with authoritarian dispositions, the more necessary psychologically based social analysis becomes. The social-character concept of Fromm and Adorno is a fading method for understanding the dynamic interaction of socio-economic social structure and psychological structure. One of its most prominent types is the "authoritarian character". Today, more than 70 years after the emergence of this theory, the question arises as to the topicality of the theoretical explanatory model. This study not only clarifies the topicality of this model, but also traces its reconfigurations in late modernity. Asceticism, deprivation and renunciation, serve as key analytical concepts for understanding Western culture and its connections to authority: from Odysseus chained to the mast, to the expulsion from paradise in Genesis, from the extra-worldly asceticism in medieval monasteries, to inner-worldly asceticism and its connection to the spirit of capitalism, to neo-asceticism in the late-modern meritocracy. This culminates in the new affirmative social character, which, today, embodies the tendency to uncritically accept the existing conditions, the tendency to affirm these conditions, the impossibility of contradiction, the impossibility of transcendence, the impossibility of transcending existing society to qualitatively new forms of existence. The empirical part of this study identifies the new affirmative social character (274 Pb; 26.1 % / sample) and also tests the F-scale (inclination to fascism) on a new sample in the 21st century. As a result, a socially relevant phenomenon emerges, which necessitates further research
MEDB-41. Identifying a subgroup of patients with early childhood sonic hedgehog-activated medulloblastoma with unfavorable prognosis after treatment with radiation-sparing regimens including intraventricular methotrexate [Abstract]
PURPOSE/METHODS: Clinical and molecular risk factors in 142 patients 3 years] 47% vs 85% [<1 year] vs 84% [1-3 years], p<0.001). No TP53 mutations were detected (n=47). DNA methylation classification identified three subgroups: SHH-1(v12.3) (n=39), SHH-2(v12.3) (n=19), and SHH-3(v12.3) (n=19), with distinct cytogenetic profiles (chromosome 2 gains in SHH-1(v12.3), very few alterations in SHH-2(v12.3), and chromosome 9q losses in SHH-3(v12.3)), age profiles (median age [years] SHH-1(v12.3): 1.7, SHH-2(v12.3): 0.9, SHH-3(v12.3): 3.0, p<0.001), and histological distribution (SHH-2(v12.3): 74% MBEN, SHH-1(v12.3)/SHH-3(v12.3): 77%/79% DMB, p<0.001). PFS was more unfavorable in patients with SHH-3(v12.3)-medulloblastoma (5-year PFS 53% vs 86% [SHH-1(v12.3)] vs 95% [SHH-2(v12.3)], p=0.002), which remained the only risk factor on multivariable Cox regression for PFS. OS was comparable (5-year OS 94% [SHH-3(v12.3)] vs 97% [SHH-1(v12.3)] vs 100% [SHH-2(v12.3)], p=0.6). 8/9 patients with SHH-3(v12.3)-medulloblastoma received radiotherapy at relapse (6 craniospinal, 2 local [1 Gorlin syndrome, 1 BRCA2 germline mutation], 1 no radiotherapy [Gorlin syndrome]). CONCLUSION: We identify patients with an increased risk of relapse when treated with radiation-sparing approaches among children with early childhood SHH-medulloblastoma. If these tumors differ from SHH-3-medulloblastoma typically described in older children remains to be verified. Treatment recommendations need to consider cancer predisposition syndromes
Cumulative occupational lumbar load and lumbar disc disease – results of a German multi-center case-control study (EPILIFT)
Background The to date evidence for a dose-response relationship between physical workload and the development of lumbar disc diseases is limited. We therefore investigated the possible etiologic relevance of cumulative occupational lumbar load to lumbar disc diseases in a multi-center case-control study. Methods In four study regions in Germany (Frankfurt/Main, Freiburg, Halle/Saale, Regensburg), patients seeking medical care for pain associated with clinically and radiologically verified lumbar disc herniation (286 males, 278 females) or symptomatic lumbar disc narrowing (145 males, 206 females) were prospectively recruited. Population control subjects (453 males and 448 females) were drawn from the regional population registers. Cases and control subjects were between 25 and 70 years of age. In a structured personal interview, a complete occupational history was elicited to identify subjects with certain minimum workloads. On the basis of job task-specific supplementary surveys performed by technical experts, the situational lumbar load represented by the compressive force at the lumbosacral disc was determined via biomechanical model calculations for any working situation with object handling and load-intensive postures during the total working life. For this analysis, all manual handling of objects of about 5 kilograms or more and postures with trunk inclination of 20 degrees or more are included in the calculation of cumulative lumbar load. Confounder selection was based on biologic plausibility and on the change-in-estimate criterion. Odds ratios (OR) and 95% confidence intervals (CI) were calculated separately for men and women using unconditional logistic regression analysis, adjusted for age, region, and unemployment as major life event (in males) or psychosocial strain at work (in females), respectively. To further elucidate the contribution of past physical workload to the development of lumbar disc diseases, we performed lag-time analyses. Results We found a positive dose-response relationship between cumulative occupational lumbar load and lumbar disc herniation as well as lumbar disc narrowing among men and women. Even past lumbar load seems to contribute to the risk of lumbar disc disease. Conclusions According to our study, cumulative physical workload is related to lumbar disc diseases among men and women
A genome-wide CRISPR screen identifies a restricted set of HIV host dependency factors
Host proteins are essential for HIV entry and replication and can be important nonviral therapeutic targets. Large-scale RNA interference (RNAi)-based screens have identified nearly a thousand candidate host factors, but there is little agreement among studies and few factors have been validated. Here we demonstrate that a genome-wide CRISPR-based screen identifies host factors in a physiologically relevant cell system. We identify five factors, including the HIV co-receptors CD4 and CCR5, that are required for HIV infection yet are dispensable for cellular proliferation and viability. Tyrosylprotein sulfotransferase 2 (TPST2) and solute carrier family 35 member B2 (SLC35B2) function in a common pathway to sulfate CCR5 on extracellular tyrosine residues, facilitating CCR5 recognition by the HIV envelope. Activated leukocyte cell adhesion molecule (ALCAM) mediates cell aggregation, which is required for cell-to-cell HIV transmission. We validated these pathways in primary human CD4 + T cells through Cas9-mediated knockout and antibody blockade. Our findings indicate that HIV infection and replication rely on a limited set of host-dispensable genes and suggest that these pathways can be studied for therapeutic intervention
Stratospheric aerosol - Observations, processes, and impact on climate
Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes
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