Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder

A pathfinder version of CHIME (the Canadian Hydrogen Intensity Mapping Experiment) is currently being commissioned at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The instrument is a hybrid cylindrical interferometer designed to measure the large scale neutral hydrogen power spectrum across the redshift range 0.8 to 2.5. The power spectrum will be used to measure the baryon acoustic oscillation (BAO) scale across this poorly probed redshift range where dark energy becomes a significant contributor to the evolution of the Universe. The instrument revives the cylinder design in radio astronomy with a wide field survey as a primary goal. Modern low-noise amplifiers and digital processing remove the necessity for the analog beamforming that characterized previous designs. The Pathfinder consists of two cylinders 37\,m long by 20\,m wide oriented north-south for a total collecting area of 1,500 square meters. The cylinders are stationary with no moving parts, and form a transit instrument with an instantaneous field of view of $\sim$100\,degrees by 1-2\,degrees. Each CHIME Pathfinder cylinder has a feedline with 64 dual polarization feeds placed every $\sim$30\,cm which Nyquist sample the north-south sky over much of the frequency band. The signals from each dual-polarization feed are independently amplified, filtered to 400-800\,MHz, and directly sampled at 800\,MSps using 8 bits. The correlator is an FX design, where the Fourier transform channelization is performed in FPGAs, which are interfaced to a set of GPUs that compute the correlation matrix. The CHIME Pathfinder is a 1/10th scale prototype version of CHIME and is designed to detect the BAO feature and constrain the distance-redshift relation.Comment: 20 pages, 12 figures. submitted to Proc. SPIE, Astronomical Telescopes + Instrumentation (2014

Long-term performance of PEM water electrolysis cells with 3D printed electrodes and low catalyst loading

Bundesministerium für Bildung und ForschungPeerReviewe

Tubular PEM electrolysis cells with a 3D-printed oxygen electrode and ALD catalyst coating

Polymer electrolyte membrane electrolysis (PEMEL) is a technology with a major role in linking the hydrogen production to renewable energy resources with a volatile behaviour such as wind and solar. High amounts of precious metals and a labour intensive production also make it a cost intensive technology. A tubular cell design has the potential to reduce production costs by co-extrusion of cells which feature a reduced sealing length. For the inner half cell, additive manufacturing (AM) of titanium offers a high degree of freedom for the electrode design to reach a high electric conductivity and active surface area. In combination with atomic layer deposition (ALD) of iridium catalyst a porous transport electrode (PTE) can be fabricated. Using planar test cell results and model based PTE design, this study demonstrates the feasibility of a tubular PEMEL cell consisting of an additively manufactured, iridium coated anode PTE in the inner half cell, an extruded membrane and a platinum coated graphite felt cathode PTE in the outer half cell. The outer titanium current collector can be replaced by an extruded graphite polymer compound current collector to reduce the amount of titanium without performance losses. The cell is operated at 60 °C in 1 mol L−1 sulphuric acid and experimentally characterized by polarization curves and electrochemical impedance spectroscopy (EIS). At 2.0 V cell potential a current density of ≈450mAcm−2 was reached corresponding to an iridium mass specific current density >1500Ag−1 which is significant larger than literature values.Bundesministerium für Bildung und ForschungPeerReviewe

Practically applicable water oxidation electrodes from 3D-printed Ti6Al4V scaffolds with surface nanostructuration and iridium catalyst coating

Bundesministerium für Bildung und Forschun

A mild method for the activation of cation exchange membranes used in tubular PEM electrolyzers

Co-extrusion of both half-cells in tubular PEM water electrolyzers can lower the costs for hydrogen production, since the number of components is reduced and the production process is simplified. However, after co-extrusion of the inner half-cell and the ion exchange membrane, the membrane is in its fluoride sulfonyl form and must be hydrolyzed to achieve the proton conductive sulfonic acid to be ready for use. Common practice is the hydrolysis using concentrated alkaline solutions, which causes a corrosion of the laminated anode electrode. We developed a less corrosive method using triethylsilanol as reactant. Tubular membranes hydrolyzed with this new procedure were characterized and tested in an electrolyzer laboratory test setup.Bundesministerium für Bildung und ForschungPeerReviewe

Immunotherapy With the PreS-based Grass Pollen Allergy Vaccine BM32 Induces Antibody Responses Protecting Against Hepatitis B Infection

Background: We have constructed and clinically evaluated a hypoallergenic vaccine for grass pollen allergy, BM32, which is based on fusion proteins consisting of peptides from the IgE binding sites of the major grass pollen allergens fused to preS (preS1 + preS2), a domain of the hepatitis B virus (HBV) large envelope protein which mediates the viral attachment and entry. Aim of this study was the characterization of the HBV-specific immune response induced by vaccination of allergic patients with BM32 and the investigation of the vaccines' potential to protect against infection with HBV. Methods: Hepatitis B-specific antibody and T cell responses of patients vaccinated with BM32 were studied using recombinant preS and synthetic overlapping peptides spanning the preS sequence. The specificities of the antibody responses were compared with those of patients with chronic HBV infection. Furthermore, the capacity of BM32-induced antibodies, to inhibit HBV infection was investigated using HepG2-hNTCP cell-based in vitro virus neutralization assays. Findings: IgG antibodies from BM32-vaccinated but not of HBV-infected individuals recognized the sequence motif implicated in NTCP (sodium-taurocholate co-transporting polypeptide)-receptor interaction of the hepatitis B virus and inhibited HBV infection. Interpretation: Our study demonstrates that the recombinant hypoallergenic grass pollen allergy vaccine BM32 induces hepatitis B-specific immune responses which protect against hepatitis B virus infection in vitro

A New and less corrosive Method for the Activation of Cation Exchange Membranes used in tubular PEM Electrolyzers

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Diethylnitrosamine (DENA) recapitulates formation of hepatic angiosarcoma in pigs.

Background & aimPrimary hepatic angiosarcoma is a rare tumor with poor prognosis. The aim of this study was to generate a new angiosarcoma model to improve research on hepatic angiosarcoma.MethodsPigs sus scrofa were treated with different regimens of diethylnitrosamine (DENA). Tissues were analyzed by histology and immunohistochemistry. Serum parameters were determined. Angiosarcoma tissue was investigated for chromosomal aberrations by aCGH analysis.ResultsAnimals of almost all different treatment regimens developed a multitude of variable liver lesions. Different tumor types such as granulation tissue type, cellular-like, hyalinization necrosis-like, angiosarcoma-like, dysplastic nodule-like, hepatocellular-like, glandular structure-like, and leiomyoma-like lesions were observed. Weekly treatment with 15 mg/kg for up to 52 weeks or a single shot of 200 mg/kg DENA led to the development of hepatic angiosarcomas. aCGH analysis of angiosarcoma tissue revealed increased alterations in tumors compared to non-tumorous tissue. Most of the chromosomal alterations were found on chromosomes 6, 7, 12, and 14.ConclusionIn this preliminary study treatment of sus scrofa with weekly injections of 15 mg/kg DENA results in a new model for primary hepatic angiosarcoma. This model may help to shed light on the pathomechanisms of primary hepatic angiosarcoma and might therefore open new treatment options