Lasing from a single quantum wire

A laser with an active volume consisting of only a single quantum wire in the 1-dimensional (1-D) ground state is demonstrated. The single wire is formed quantum-mechanically at the T-intersection of a 14 nm Al_{0.07}Ga_{0.93}As quantum well and a 6 nm GaAs quantum well, and is embedded in a 1-D single-mode optical waveguide. We observe single-mode lasing from the quantum wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.Comment: 4 pages including 4 figure

Imaging of emission patterns in a T-shaped quantum wire laser

Spatially and spectrally resolved microscopic images of spontaneous and stimulated emissions are imaged at the mirror facets of a GaAs T-shaped quantum wire laser with high uniformity. Laser emission from the one-dimensional ground state reveals a circular image located at the core of a T-shaped optical waveguide but significantly smaller in area than the low power spontaneous emission from the same waveguide. These images unambiguously allow assignment of all spontaneous and laser emissions to the wire ground state and respective intersecting wells in the structure.Comment: 4 pages, 3 figure

Gata6 Promotes GLI3 Repressor Activities in the Limb

Gli3 is a major regulator of Hedgehog signaling during limb development. In the anterior mesenchyme, GLI3 is proteolytically processed into GLI3R, a truncated repressor form that inhibits Hedgehog signaling. Although numerous studies have identified mechanisms that regulate Gli3 function in vitro, it is not completely understood how Gli3 function is regulated in vivo. In this study, we show a novel mechanism of regulation of GLI3R activities in limb buds by Gata6, a member of the GATA transcription factor family. We show that conditional inactivation of Gata6 prior to limb outgrowth by the Tcre deleter causes preaxial polydactyly, the formation of an anterior extra digit, in hindlimbs. A recent study suggested that Gata6 represses Shh transcription in hindlimb buds. However, we found that ectopic Hedgehog signaling precedes ectopic Shh expression. In conjunction, we observed Gata6 and Gli3 genetically interact, and compound heterozygous mutants develop preaxial polydactyly without ectopic Shh expression, indicating an additional prior mechanism to prevent polydactyly. These results support the idea that Gata6 possesses dual roles during limb development: enhancement of Gli3 repressor function to repress Hedgehog signaling in the anterior limb bud, and negative regulation of Shh expression. Our in vitro and in vivo studies identified that GATA6 physically interacts with GLI3R to facilitate nuclear localization of GLI3R and repressor activities of GLI3R. Both the genetic and biochemical data elucidates a novel mechanism by Gata6 to regulate GLI3R activities in the anterior limb progenitor cells to prevent polydactyly and attain proper development of the mammalian autopod

Detection of Lymphocyte Subsets by Monoclonal Antibodies in Aged and Young Humans

With the use of Leu-series monoclonal antibodies, peripheral blood lymphocyte subsets in aged and young humans were determined. 1) In comparison with young individuals, Leu-1+ cells and Leu-2a+ cells were decreased, whereas Leu-7+ cells and Leu-3a/Leu-2a were increased in aged individuals. 2) No sex difference could be observed in lymphocyte subsets. 3) PHA response of lymphocytes showed a negative correlation with Leu-2a+ cells and a positive correlation with Leu-3a/Leu-2a in aged individuals

Interleukin-2 Production and Lymphocyte Proliferation in Aged and Young Humans

A study was made on the effect of aging on the production of Interleukin-2 (IL-2) and lymphocyte proliferation of human peripheral blood lymphocytes. 1) In comparison with young individuals, IL-2 production tended to decrease in aged individuals, while lymphocyte proliferation showed a significant decrease. 2) A significant correlation was observed between IL-2 production and lymphocyte proliferation in both the aged and young human populations. 3) IL-2 production showed a negative correlation with Leu-2a positive rate and a positive correlation with Leu-3a/Leu-2a ratio in aged individuals

Immune Functions of Former Poison Gas Workers I. Mitogenic response of lymphocytes and serum factors

The relation of depressed immune function to carcinogenesis has been estimated in the living body. The authors have measured the immunological parameters in former poison gas workers, a group having a high risk of carcinogenesis, for comparison with age matched normal controls and the following results were obtained. 1) With regard to serum factors, no significant difference could be demonstrated between normal controls and poison gas workers in such immunoglobulins as IgG, IgA, and IgM, in acute phase reactants such as α1-AT, α1-AG, α2-HS and C3 and in such tumor markers as CEA, ferritin, and β2-microglobulin. Furthermore, no difference could be observed in the positive rate of immune complex and in complement activity. 2) No difference could be observed between the two groups with regard to tuberculin skin reaction and number of lymphocytes, but the longer the duration of work at the poison gas factory, the more significant was the increase in those who showed negative tuberculin skin reaction. 3) In comparison with normal controls, mitogenic response to PHA showed a significant decrease in poison gas workers, but no significant difference could be seen in mitogenic response to Con A and PPD and in mixed lymphocyte reaction. 4) No significant difference could be demonstrated between the two groups in the inhibitory effects of serum on mitogenic response to PHA and Con A and on mixed lymphocyte reaction

Comprehensive study of liposome-assisted synthesis of membrane proteins using a reconstituted cell-free translation system

Membrane proteins play pivotal roles in cellular processes and are key targets for drug discovery. However, the reliable synthesis and folding of membrane proteins are significant problems that need to be addressed owing to their extremely high hydrophobic properties, which promote irreversible aggregation in hydrophilic conditions. Previous reports have suggested that protein aggregation could be prevented by including exogenous liposomes in cell-free translation processes. Systematic studies that identify which membrane proteins can be rescued from irreversible aggregation during translation by liposomes would be valuable in terms of understanding the effects of liposomes and developing applications for membrane protein engineering in the context of pharmaceutical science and nanodevice development. Therefore, we performed a comprehensive study to evaluate the effects of liposomes on 85 aggregation-prone membrane proteins from Escherichia coli by using a reconstituted, chemically defined cell-free translation system. Statistical analyses revealed that the presence of liposomes increased the solubility of >90% of the studied membrane proteins, and ultimately improved the yields of the synthesized proteins. Bioinformatics analyses revealed significant correlations between the liposome effect and the physicochemical properties of the membrane proteins

UNIFORM-1: First Micro-Satellite of Forest Fire Monitoring Constellation Project

UNIFORM Project had started in November 2010 with its vision of constructing sustainable micro-satellite constellation system via cooperation with various countries. International collaboration and actual utilization of the system are the keys of the project for realizing sustainable space industry. Forest fire monitoring was selected as the first mission. UNIFORM-1 is the first micro-satellite, weighing 50kg with 50cm cubic size, in this project and launched on May 24th, 2014 by H-IIA rocket as a secondary payload. UNIFORM-1 carries two cameras of area sensor: uncooled microbolometer camera and visible light camera. Both have GSD of less than 200[m] and swath is about 100km. These two cameras are used for localization of heat anomaly spots. The acquired image will be overlaid on global map to generate a “forest fire map” which will be released so that local fire department of the concerning country can take action promptly and extinguish forest fire. Other key features of this satellite are following: 3-axis control with reaction wheels, deployable solar array panel wings, lithium ion battery, and 10Mbps X-band transmitter for mission data. Design and test result of UNIFORM-1 flight model is explained in detail in this paper. As the result of initial operation of five days after launch, image of infrared camera was successfully acquired

Exploring SDA sensor architectures for the surveillance of geosynchronous spacecraft

Significant changes have taken place in the space domain over the past decade, with a growing number of emerging space-faring nations and commercial actors gaining access to the operational environment. The consequential diversification of space activities has brought about a need for a reassessment of space domain awareness (SDA) capabilities. Numerous states are developing their operational capability to undertake space-based activities, with potentially widespread ramifications for the safety of spacecraft. Rendezvous and proximity operations are becoming more prevalent in the geosynchronous (GSO) region for mission lifetime extension, active removal of debris, and satellite inspection, in all cases giving rise to novel challenges for SDA systems. What's more, there remains a largely uncharacterised population of small debris in the vicinity of the GSO region, uncovered by bespoke surveys with large aperture telescopes, and posing a significant risk to active satellites. In 2022, the UK Space Agency commissioned a study into the requirements and opportunities for SDA in the UK, carried out by CGI with support from the Global Network On Sustainability In Space (GNOSIS) and UKspace. The study highlighted research and development of sovereign sensors as one of its key recommendations, both to improve the UK's sensing capability and to contribute to closing gaps in global SDA capability. To this end, we explore the key requirements for future SDA sensor architectures, with a focus on ground-based electro-optical systems for the surveillance of spacecraft in the GSO region. Archival two-line element sets are used to simulate catalogued resident space objects (RSOs) passing through a grid of surveillance regions, tasked with monitoring the neighbourhoods of high-value assets in the vicinity of the geostationary belt, while the derived population from ESA's Meteoroid and Space Debris Terrestrial Environment Reference (MASTER) model is used as a basis for simulating the GSO debris field. We assess the observability of transiting RSOs from the vantage point of La Palma, Canary Islands, taking a variety of observational constraints into account, including the Earth's shadow, lunation, and the galactic plane. We examine the performance of the simulated surveillance regions in the context of comprehensive, yet cost-effective SDA provision. Estimated costs are weighed against important metrics for essential SDA tasks (e.g., catalogue maintenance , change detection, and conjunction analysis), such as the total traffic observed per night, the cadence of the observations, and the temporal coverage of registered RSOs. The results of the simulation are used to inform a discussion of key sensor architecture requirements for effective SDA of GSO assets, taking into consideration a combination of sensor characteristics (e.g., sensitivity, resolution, and wavelength band) and other factors (e.g., geographical placement, site quality, and observational strategy) influencing SDA capabilities. We provide a commentary on the advantages and limitations of the different architectures considered and conclude with a list of recommendations for the designs of future SDA systems for the protection of GSO spacecraft