131 research outputs found
High-Q distributed-Bragg-grating laser cavities
Applying Bragg gratings in Al2O3 channel waveguides, we demonstrate distributed Bragg reflectors with Q-factors of 1.02x10e6. An integrated Al2O3:Yb3+ waveguide laser with 67% slope efficiency and 47 mW output power is achieved with such cavities
Single-Frequency, Narrow-Linewidth Distributed Feedback Waveguide Laser in Al2O3:Er3+ on Silicon
A distributed feedback channel waveguide laser in erbium-doped aluminum oxide on a silicon substrate is reported. The optically pumped laser has a threshold pump power of 15 mW and emits 3 mW in single-frequency operation at 1545.2 nm wavelength with a slope efficiency of 6.2% and linewidth of 15 kHz
A Chemically Defined Hydrogel for Human Liver Organoid Culture
End-stage liver diseases are an increasing health burden, and liver transplantations are currently the only curative treatment option. Due to a lack of donor livers, alternative treatments are urgently needed. Human liver organoids are very promising for regenerative medicine; however, organoids are currently cultured in Matrigel, which is extracted from the extracellular matrix of the Engelbreth-Holm-Swarm mouse sarcoma. Matrigel is poorly defined, suffers from high batch-to-batch variability and is of xenogeneic origin, which limits the clinical application of organoids. Here, a novel hydrogel based on polyisocyanopeptides (PIC) and laminin-111 is described for human liver organoid cultures. PIC is a synthetic polymer that can form a hydrogel with thermosensitive properties, making it easy to handle and very attractive for clinical applications. Organoids in an optimized PIC hydrogel proliferate at rates comparable to those observed with Matrigel; proliferation rates are stiffness-dependent, with lower stiffnesses being optimal for organoid proliferation. Moreover, organoids can be efficiently differentiated toward a hepatocyte-like phenotype with key liver functions. This proliferation and differentiation potential maintain over at least 14 passages. The results indicate that PIC is very promising for human liver organoid culture and has the potential to be used in a variety of clinical applications including cell therapy and tissue engineering
Large-scale production of LGR5-positive bipotential human liver stem cells
Background and Aims: The gap between patients on transplant waiting lists and available donor organs is steadily increasing. Human organoids derived from leucineârich repeatâcontaining G proteinâcoupled receptor 5 (LGR5)âpositive adult stem cells represent an exciting new cell source for liver regeneration; however, culturing large numbers of organoids with current protocols is tedious and the level of hepatic differentiation is limited. Approach and Results: Here, we established a method for the expansion of large quantities of human liver organoids in spinner flasks. Due to improved oxygenation in the spinner flasks, organoids rapidly proliferated and reached an average 40âfold cell expansion after 2 weeks, compared with 6âfold expansion in static cultures. The organoids repopulated decellularized liver discs and formed liverâlike tissue. After differentiation in spinner flasks, mature hepatocyte markers were highly upâregulated compared with static organoid cultures, and cytochrome p450 activity reached levels equivalent to hepatocytes. Conclusions: We established a highly efficient method for culturing large numbers of LGR5âpositive stem cells in the form of organoids, which paves the way for the application of organoids for tissue engineering and liver transplantation
Participatory Budgeting and Local Government in a Vertical Society: A Japanese Story
This article examines a case of participatory budgeting in Japanese local government. The article demonstrates how cultural values interact with stages of budgeting (in our case, the co-planning or consultation phase of budgeting). We find three key stakeholders â councillors, administrators and citizens â have varying degree of participation in the budget process. While direct citizen participation has been limited and challenging, we find that local associations and councillors work as lobbyists to influence the budget less publicly. The budget desk led by the mayor plays the dominant role. This article contributes to the broader debate on local government reforms and their translation into varied contexts by problematising such a linear adoption of knowledge from a cultural perspective
Damage accumulation in thin ruthenium films induced by repetitive exposure to femtosecond XUV pulses below the single shot ablation threshold
The process of damage accumulation in thin ruthenium films exposed to multiple femtosecond XUV free electron laser FEL pulses below the critical angle of reflectance at the Free electron LASer facility in Hamburg FLASH was experimentally analyzed. The multi shot damage threshold is found to be lower than single shot damage threshold. Detailed analysis of the damage morphology and its dependence on irradiation conditions justifies the assumption that cavitation induced by the FEL pulse is the prime mechanism responsible for multi shot damage in optical coating
Large-Scale Production of LGR5-Positive Bipotential Human Liver Stem Cells
Background and Aims: The gap between patients on transplant waiting lists and available donor organs is steadily increasing. H
Industrial associations as ideational platforms : why Japan resisted American-style shareholder capitalism
Significant wage and treatment differentials between regular workers in long-term employment and precarious non-regular workers have been a major political issue in Japan since the mid-1990s. I argue this phenomenon was caused by Japanese societyâs resistance to American neoliberal hegemony. Why has Japan resisted it, and how has the resistance resulted in the rapid increase in the working poor? I contend anti-liberal, anti-free market norms of Japanese society centred on âsystemic supportâ have bolstered resistance to convergence in order to prevent capitalist dominance from severing long-term social ties, such as management-labour cooperation. My broadened definition of systemic support incorporates dominant elitesâ support and protection of subordinates in exchange for their loyalty and obedience. This paper will explore reasons for the resistance to convergence by examining an ideational conflict within Japanese elites between the market liberalisation and anti-free market camps, particularly between two major industrial associations, Keidanren and Keizai Doyukai, which have played a key role as âideational platformsâ for Japanese corporate society. Under the Hashimoto (1996-8) and Koizumi (2001-6) administrations, the market liberalisation camp gained influence, but since 2006, both the anti-free market camp and its subordinates (e.g. regular workers) have driven anti-neoliberal backlash
âHot standardsâ for the thermoacidophilic archaeon Sulfolobus solfataricus
Within the archaea, the thermoacidophilic crenarchaeote Sulfolobus solfataricus has become an important model organism for physiology and biochemistry, comparative and functional genomics, as well as, more recently also for systems biology approaches. Within the Sulfolobus Systems Biology (âSulfoSYSâ)-project the effect of changing growth temperatures on a metabolic network is investigated at the systems level by integrating genomic, transcriptomic, proteomic, metabolomic and enzymatic information for production of a silicon cell-model. The network under investigation is the central carbohydrate metabolism. The generation of high-quality quantitative data, which is critical for the investigation of biological systems and the successful integration of the different datasets, derived for example from high-throughput approaches (e.g., transcriptome or proteome analyses), requires the application and compliance of uniform standard protocols, e.g., for growth and handling of the organism as well as the ââomicsâ approaches. Here, we report on the establishment and implementation of standard operating procedures for the different wet-lab and in silico techniques that are applied within the SulfoSYS-project and that we believe can be useful for future projects on Sulfolobus or (hyper)thermophiles in general. Beside established techniques, it includes new methodologies like strain surveillance, the improved identification of membrane proteins and the application of crenarchaeal metabolomics
Regional contribution to ventricular stroke volume is affected on the left side, but not on the right in patients with pulmonary hypertension
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