Ebene Keramiksubstrate und neue Montagetechnologien zum Aufbau hybrid-optischer Systeme

Subject of the thesis are research results concerning the packaging and assembly of hybrid optical systems. The discussed packaging concept is suitable for miniaturized, free-space and two-dimensional optical systems that allow to realize a broad range of optical functions, but it is also capable for the integration of electronical components as well as silicon micromachined parts. Basic idea is to use planar ceramic printed circuit boards (PCB) made of aluminum oxide (Al2O3) or Low Temperature Cofired Ceramics (LTCC) as a system platform for the optical assembly. Ceramic PCB are already well known from electronics manufacturing and by additionally embedding mechanical mounting structures within the substrate optical components can be assembled on top of the platform. The geometrical variety of these mounting structures and their design are the first focus of the thesis. In a second part the assembly technologies are described and evaluated that are necessary to place, adjust and finally join optical components in such mounting structures. Procedures from electronics manufacturing and assembly like "Pick& Place" need to be adapted since positioning and adjustment of optical components often require more than four degrees of freedom. In the thesis two types of assembly strategies that take the issues of optical mounting into account and use mechanical stops or the adjusted optical function for a position representation of the component are evaluated. The investigations were carried out by designing and assembling an optoelectronic demonstrator system. The results show that if the mounting structures within the ceramic PCB are used as mechanical stops for the positioning of optical components the mounting structure accuracies, currently ranging from ±27 µm to ±90 µm, constrain the packaging concept. By using adjustment processes an enhanced positioning accuracy of < ±5 µm was demonstrated. Thus and also concerning the various non-optical functionalities that can be integrated the overall conclusion of the thesis is that ceramic PCB are well suitable for the integration of optics and electronics on a common platform, especially if the demands on the positioning accuracies for the optical components are above 5 µm

Perspectives for applications of quantum imaging

Quantum imaging is a multifaceted field of research that promises highly efficient imaging in extreme spectral ranges as well as ultralow‐light microscopy. Since the first proof‐of‐concept experiments over 30 years ago, the field has evolved from highly fascinating academic research to the verge of demonstrating practical technological enhancements in imaging and microscopy. Here, the aim is to give researchers from outside the quantum optical community, in particular those applying imaging technology, an overview of several promising quantum imaging approaches and evaluate both the quantum benefit and the prospects for practical usage in the near future. Several use case scenarios are discussed and a careful analysis of related technology requirements and necessary developments toward practical and commercial application is provided

Book Review: The Global Political Economy of Raúl Prebisch

This edited volume by Matias Margulis examines Raúl Prebisch’s ideas, agency, and influence in an interdisciplinary manner, with a particular emphasis on his relevance for Global Political Economy (GPE). This interdisciplinary approach reminds the reader that Prebisch was indeed much more than just an economic theorist and that his influence on development policy was profound. An important contribution of this book is the emphasis on how Prebisch’s ideas changed over time, partly in result of the failure of his political projects, first in Argentina and later in ECLAC. With time, Prebisch became more acutely aware of the importance of political power, not just economic capabilities, for shaping institutions as well as for forming the rules of the world economy. This is important to emphasize, as Prebisch’s work is sometimes criticized for being overly economistic (see, for example, Palma 2016; Shivji 2016), which is not a valid critique for his work during the last part of his life. There is a clear parallel to be drawn between what Margulis calls the peripheralization of Prebisch in GPE and the role of Prebisch’s ideas in the Economics field (see, for example, Kufakurinani et al. 2017). With the term peripheralization, Margulis is referring to the transformation of Prebisch from providing intellectual leadership in international development in the 1950s–1970s, to being relegated to a “historical footnote” in the 1980s. Prebisch also disappeared from the Economics curricula in the 1980s as suddenly, and perhaps more completely, as he disappeared from GPE (Kvangraven 2017). Although his core ideas may be found in mainstream economic history literature such as Kenneth Pomeranz’s (2000) The Great Divergence or Sven Beckert’s (2014) Empire of Cotton, such authors tend to not cite Prebisch as a source, perhaps because they are unaware of the origin of the concepts they use in their analysis. ECLAC itself also explicitly abandoned Prebisch’s main ideas in 1994 in favor of a policy of “open regionalism” (ECLAC 1994). Furthermore, Margulis’s observation of Prebisch often being incorrectly portrayed in GPE (e.g., as an advocate for economic autarky) is also paralleled in Economics. This can partly be attributed to the rewriting of the intellectual history of these fields.1 Eurocentricism in both GPE and Economics is another possible reason for the exclusion of Prebisch from the field

Phylogenomics of Mycobacterium africanum reveals a new lineage and a complex evolutionary history.

Human tuberculosis (TB) is caused by members of the Mycobacterium tuberculosis complex (MTBC). The MTBC comprises several human-adapted lineages known as M. tuberculosis sensu stricto, as well as two lineages (L5 and L6) traditionally referred to as Mycobacterium africanum. Strains of L5 and L6 are largely limited to West Africa for reasons unknown, and little is known of their genomic diversity, phylogeography and evolution. Here, we analysed the genomes of 350 L5 and 320 L6 strains, isolated from patients from 21 African countries, plus 5 related genomes that had not been classified into any of the known MTBC lineages. Our population genomic and phylogeographical analyses showed that the unclassified genomes belonged to a new group that we propose to name MTBC lineage 9 (L9). While the most likely ancestral distribution of L9 was predicted to be East Africa, the most likely ancestral distribution for both L5 and L6 was the Eastern part of West Africa. Moreover, we found important differences between L5 and L6 strains with respect to their phylogeographical substructure and genetic diversity. Finally, we could not confirm the previous association of drug-resistance markers with lineage and sublineages. Instead, our results indicate that the association of drug resistance with lineage is most likely driven by sample bias or geography. In conclusion, our study sheds new light onto the genomic diversity and evolutionary history of M. africanum, and highlights the need to consider the particularities of each MTBC lineage for understanding the ecology and epidemiology of TB in Africa and globally

What Is Resistance? Impact of Phenotypic versus Molecular Drug Resistance Testing on Therapy for Multi- and Extensively Drug-Resistant Tuberculosis.

Rapid and accurate drug susceptibility testing (DST) is essential for the treatment of multi- and extensively drug-resistant tuberculosis (M/XDR-TB). We compared the utility of genotypic DST assays with phenotypic DST (pDST) using Bactec 960 MGIT or Löwenstein-Jensen to construct M/XDR-TB treatment regimens for a cohort of 25 consecutive M/XDR-TB patients and 15 possible anti-TB drugs. Genotypic DST results from Cepheid GeneXpert MTB/RIF (Xpert) and line probe assays (LPAs; Hain GenoType MTBDRplus 2.0 and MTBDRsl 2.0) and whole-genome sequencing (WGS) were translated into individual algorithm-derived treatment regimens for each patient. We further analyzed if discrepancies between the various methods were due to flaws in the genotypic or phenotypic test using MIC results. Compared with pDST, the average agreement in the number of drugs prescribed in genotypic regimens ranged from just 49% (95% confidence interval [CI], 39 to 59%) for Xpert and 63% (95% CI, 56 to 70%) for LPAs to 93% (95% CI, 88 to 98%) for WGS. Only the WGS regimens did not contain any drugs to which pDST showed resistance. Importantly, MIC testing revealed that pDST likely underestimated the true rate of resistance for key drugs (rifampin, levofloxacin, moxifloxacin, and kanamycin) because critical concentrations (CCs) were too high. WGS can be used to rule in resistance even in M/XDR strains with complex resistance patterns, but pDST for some drugs is still needed to confirm susceptibility and construct the final regimens. Some CCs for pDST need to be reexamined to avoid systematic false-susceptible results in low-level resistant isolates

Space QUEST mission proposal: experimentally testing decoherence due to gravity

Models of quantum systems on curved space-times lack sufficient experimental verification. Some speculative theories suggest that quantum properties, such as entanglement, may exhibit entirely different behavior to purely classical systems. By measuring this effect or lack thereof, we can test the hypotheses behind several such models. For instance, as predicted by Ralph and coworkers [T C Ralph, G J Milburn, and T Downes, Phys. Rev. A, 79(2):22121, 2009, T C Ralph and J Pienaar, New Journal of Physics, 16(8):85008, 2014], a bipartite entangled system could decohere if each particle traversed through a different gravitational field gradient. We propose to study this effect in a ground to space uplink scenario. We extend the above theoretical predictions of Ralph and coworkers and discuss the scientific consequences of detecting/failing to detect the predicted gravitational decoherence. We present a detailed mission design of the European Space Agency's (ESA) Space QUEST (Space - Quantum Entanglement Space Test) mission, and study the feasibility of the mission schema.Comment: 18 pages, 13 figures, included radiation damage to detectors in appendi

Mikropumpe

The micro pump has fluid substrate (2) that is equipped with a pump chamber (1) which is entirely covered by a polymer membrane (3) made of polycarbonate. The polymer membrane is actuated by membrane actuators (6,7) containing metals, carbon nanotubes and electrically conductive polymers. The fluid inflow and inflow processes are performed through a micro-channel. Several nanoscale surface structures are provided at specific regions of micro-channel, such that directed pumping action is achieved by direction-dependent flow resistance. An independent claim is included for a method for producing micro pump