1,069 research outputs found
Entwicklung, Aufbau & Erprobung eines Sekundärreflektors zur experimentellen Verwendung im Hochleistungsstrahler SYNLIGHT
Potential of Opuntia seed oil for livelihood improvement in semi-arid Madagascar
The coastal area of the Mahafaly Plateau in southwestern Madagascar is prone to droughts, as well as to other environmental risks, resulting in frequent crop failures, famines, and extreme poverty. Thus, the identification of potential complementary livelihood sources has been identified as a crucial step for the sustainable development of the region. In this contribution, we assess the potential of prickly pear seed oil production as an income alternative for local communities. The prickly pears are cacti in the genus Opuntia Mill. and they are highly abundant in the region, particularly as living fences on farmland. From the seeds of its fruit, high-priced seed oil can be extracted. To investigate its economic potential, we inventoried prickly pears in field hedgerows through vegetation inventories and estimated the amount of seed oil that could be produced per household based on field sampling and laboratory analysis. To assess the socioeconomic impact of a potential large-scale project of regional Opuntia seed oil production, we conducted interviews with 51 farming households on human Opuntia consumption, the utilization of its cladodes as fodder, and other livelihood functions.Five different prickly pears occur in the research region. We found that two out of these five species are highly important socioeconomically (Opuntia monacantha and O. streptacantha) and contribute >50% to total food intake during periods of food shortage. Likewise, these species are consumed as a key water source and used as livestock fodder. In contrast, the other three Opuntia species are barely eaten by local residents or by livestock (O. dillenii, O. stricta and O. phaeacantha). These species are more spiny, and their fruits are virtually inedible due to a much higher seed content. The combination of low nutritional value and high seed content suggests promising seed oil production potential for these types of Opuntia. To avoid competition between human nutrition and the commercialization of local Opuntia seeds, sourcing strategies should exclusively target the fruit of the two high seed species. However, investments for oil mills, skilled staff, and adequate logistics would be needed to create local value from this underrated resource in the Mahafaly region
Modeling of an efficient singlet-triplet spin qubit to photon interface assisted by a photonic crystal cavity
Efficient interconnection between distant semiconductor spin qubits with the
help of photonic qubits would offer exciting new prospects for future quantum
communication applications. In this paper, we optimize the extraction
efficiency of a novel interface between a singlet-triplet spin qubit and a
photonic qubit. The interface is based on a 220 nm thick GaAs/AlGaAs
heterostructure membrane and consists of a gate-defined double quantum dot
(GDQD) supporting a singlet-triplet qubit, an optically active quantum dot
(OAQD) consisting of a gate-defined exciton trap, a photonic crystal cavity
providing in-plane optical confinement and efficient out-coupling to an ideal
free space Gaussian beam while accommodating the gate wiring of the GDQD and
OAQD, and a bottom gold reflector to recycle photons and increase the optical
extraction efficiency. All essential components can be lithographically defined
and deterministically fabricated on the GaAs/AlGaAs heterostructure membrane,
which greatly increases the scalability of on-chip integration. According to
our simulations, the interface provides an overall coupling efficiency of 28.7%
into a free space Gaussian beam, assuming an SiO2 interlayer filling the space
between the reflector and the membrane. The performance can be further
increased by undercutting this SiO2 interlayer below the photonic crystal. In
this case, the overall efficiency is calculated to be 48.5%
Experimental Investigation of a System of two Vacuum Solar Receivers for the Continuous Reduction of Ceria Particles
A solar receiver for the continuous reduction of redox particles under vacuum conditions has been developed previously as part of a system to produce hydrogen from solar energy. Here, we report about a joint effort of Sandia and DLR to improve the receivers design and to demonstrate a system of two receivers with different vacuum pressures at DLR’s solar simulator Synlight. We focus on the design and experimental investigation of three components: the novel beam down mirror, the novel secondary concentrator and the improved version of the particle conveying plate in the receiver. Irradiation test results and heat transfer analyses of the beam-down mirror and the secondary concentrator are being presented. The motion of the conveyor plate was improved by a MATLAB model, which predicts the transport speed of the particles on the conveyor
Development of polygon forming processes for aerospace engineering
The focus of this research lays on the further development of the Polygon Forming Technology, which is already successfully used for cold forming components in the aerospace industry. One example is the fuselage shell of the Airbus Beluga XL. According to the current state of the art it is possible to incrementally form large cylindrical or conical fuselage components by Polygon Forming. With the use of so-called infills, the Polygon Forming process can also be used to form components with pockets milled in the initial plane state. The limits of this technology exclude the creation of spherical geometries, such as those used in the front or rear fuselage sections of aircrafts. Presently, such components are produced by more complex stretch forming processes, which result in a considerable amount of scrap. In this work, a tool is developed to replicate the Polygon Forming process on experimental scale at the Institute of Forming Technology and Machines (IFUM) for materials commonly used in aerospace engineering. In addition, a downscaled pre-test tool is developed to investigate different tool geometries for incremental spherical forming inexpensive and easy according to the method of rapid prototyping
Inhibition of DHCR24 activates LXRα to ameliorate hepatic steatosis and inflammation
Liver X receptor (LXR) agonism has theoretical potential for treating NAFLD/NASH, but synthetic agonists induce hyperlipidemia in preclinical models. Desmosterol, which is converted by Δ24-dehydrocholesterol reductase (DHCR24) into cholesterol, is a potent endogenous LXR agonist with anti-inflammatory properties. We aimed to investigate the effects of DHCR24 inhibition on NAFLD/NASH development. Here, by using APOE*3-Leiden. CETP mice, a well-established translational model that develops diet-induced human-like NAFLD/NASH characteristics, we report that SH42, a published DHCR24 inhibitor, markedly increases desmosterol levels in liver and plasma, reduces hepatic lipid content and the steatosis score, and decreases plasma fatty acid and cholesteryl ester concentrations. Flow cytometry showed that SH42 decreases liver inflammation by preventing Kupffer cell activation and monocyte infiltration. LXRα deficiency completely abolishes these beneficial effects of SH42. Together, the inhibition of DHCR24 by SH42 prevents diet-induced hepatic steatosis and inflammation in a strictly LXRα-dependent manner without causing hyperlipidemia. Finally, we also showed that SH42 treatment decreased liver collagen content and plasma alanine transaminase levels in an established NAFLD model. In conclusion, we anticipate that pharmacological DHCR24 inhibition may represent a novel therapeutic strategy for treatment of NAFLD/NASH.</p
Distinct Mutational Profile of Lynch Syndrome Colorectal Cancers Diagnosed under Regular Colonoscopy Surveillance
Regular colonoscopy even with short intervals does not prevent all colorectal cancers (CRC) in Lynch syndrome (LS). In the present study, we asked whether cancers detected under regular colonoscopy surveillance (incident cancers) are phenotypically different from cancers detected at first colonoscopy (prevalent cancers). We analyzed clinical, histological, immunological and mutational characteristics, including panel sequencing and high-throughput coding microsatellite (cMS) analysis, in 28 incident and 67 prevalent LS CRCs (n total = 95). Incident cancers presented with lower UICC and T stage compared to prevalent cancers (p < 0.0005). The majority of incident cancers (21/28) were detected after previous colonoscopy without any pathological findings. On the molecular level, incident cancers presented with a significantly lower KRAS codon 12/13 (1/23, 4.3% vs. 11/21, 52%; p = 0.0005) and pathogenic TP53 mutation frequency (0/17, 0% vs. 7/21, 33.3%; p = 0.0108,) compared to prevalent cancers; 10/17 (58.8%) incident cancers harbored one or more truncating APC mutations, all showing mutational signatures of mismatch repair (MMR) deficiency. The proportion of MMR deficiency-related mutational events was significantly higher in incident compared to prevalent CRC (p = 0.018). In conclusion, our study identifies a set of features indicative of biological differences between incident and prevalent cancers in LS, which should further be monitored in prospective LS screening studies to guide towards optimized prevention protocols.Peer reviewe
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