Introducing the MeVCube concept: a CubeSat for MeV observations

Despite the impressive progress achieved both by X-ray and gamma-ray observatories in the last few decades, the energy range between ∼ 200 keV and ∼ 50 MeV remains poorly explored. COMPTEL, on-board the Compton Gamma-Ray Observatory (CGRO, 1991-2000), opened the MeV gamma-ray band as a new window to astronomy, performing the first all-sky survey in the energy range from 0.75 to 30 MeV. More than 20 years after the de-orbit of CGRO, no successor mission is yet operating. Over the past years many concepts have been proposed, for new observatories exploring different configurations and imaging techniques; a selection of the most recent ones includes AMEGO, ETCC, GECCO and COSI. We propose here a novel concept for a Compton telescope based on the CubeSat standard, named MeVCube, with the advantages of small cost and relatively short development time. The scientific payload is based on two layers of pixelated Cadmium-Zinc-Telluride (CdZnTe) detectors, coupled with low-power read-out electronics (ASIC, VATA450.3). The performance of the read-out electronics and CdZnTe custom designed detectors have been measured extensively at DESY [1]. The performance of the telescope is accessed through simulations: despite a small effective area limited to a few cm2, MeVCube can reach an angular resolution of 1.5° and a sensitivity comparable to the one achieved by the last generation of large-scale satellites like COMPTEL and INTEGRAL. Combined with a large field-of-view and a moderate cost, MeVCube can be a powerful instrument for transient observations and searches of electromagnetic counterparts of gravitational wave events.Peer Reviewe

Introducing the MeVCube concept: a CubeSat for MeV observations

Despite the impressive progress achieved both by X-ray and gamma-ray observatories in the last few decades, the energy range between $\sim200\;\mathrm{keV}$ and $\sim50\;\mathrm{MeV}$ remains poorly explored. COMPTEL, on-board the Compton Gamma-Ray Observatory (CGRO, $1991$-$2000$), opened the MeV gamma-ray band as a new window to astronomy, performing the first all-sky survey in the energy range from $0.75$ to $30\;\mathrm{MeV}$. More than $20$ years after the de-orbit of CGRO, no successor mission is yet operating. Over the past years many concepts have been proposed, for new observatories exploring different configurations and imaging techniques; a selection of the most recent ones includes AMEGO, ETCC, GECCO and COSI. We propose here a novel concept for a Compton telescope based on the CubeSat standard, named MeVCube, with the advantages of small cost and relatively short development time. The scientific payload is based on two layers of pixelated Cadmium-Zinc-Telluride (CdZnTe) detectors, coupled with low-power read-out electronics (ASIC, VATA450.3). The performance of the read-out electronics and CdZnTe custom designed detectors have been measured extensively at DESY. The performance of the telescope is accessed through simulations: despite a small effective area limited to a few $\mathrm{cm}^{2}$, MeVCube can reach an angular resolution of $1.5^{\circ}$ and a sensitivity comparable to the one achieved by the last generation of large-scale satellites like COMPTEL and INTEGRAL. Combined with a large field-of-view and a moderate cost, MeVCube can be a powerful instrument for transient observations and searches of electromagnetic counterparts of gravitational wave events

Characterization of a CdZnTe detector for a low-power CubeSat application

We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for the MeVCube project: a small Compton telescope on a CubeSat platform. MeVCube is expected to cover the energy range between 200 keV and 4 MeV, with a sensitivity comparable to the one of the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a 3-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed by Ideas, with a power consumption of only 0.25 mW/channel, which exhibits good performance in terms of dynamic range, noise and linearity. A 2.0 cm× 2.0 cm× 1.5 cm CdZnTe detector, with a custom 8 × 8 pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discrete Amptek A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around 3% FWHM has been measured at a gamma energy of 662 keV; at 200 keV the average energy resolution is 6.5%, decreasing to ≲ 2% at energies above 1 MeV. A 3-D spatial resolution of ≈ 2 mm is achieved in each dimension.Peer Reviewe

Characterization of a CdZnTe detector for a low-power CubeSat application

We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for the \emph{MeVCube} project: a small Compton telescope on a CubeSat platform. \emph{MeVCube} is expected to cover the energy range between $200\;\mathrm{keV}$ and $4\;\mathrm{MeV}$, with performance comparable to the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a $3$-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed by \emph{Ideas}, with a power consumption of only $0.25\;\mathrm{mW/channel}$, which exhibits good performance in terms of dynamic range, noise and linearity. A $2.0\;\mathrm{cm} \times 2.0\;\mathrm{cm} \times 1.5\;\mathrm{cm}$ CdZnTe detector, with a custom $8 \times 8$ pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discrete \emph{Amptek} A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around $3\%$ FWHM has been measured at a gamma energy of $662\;\mathrm{keV}$; at $200\;\mathrm{keV}$ the average energy resolution is $6.5\%$, decreasing to $\lesssim 2\%$ at energies above $1\;\mathrm{MeV}$. A $3$-D spatial resolution of $\approx 2\,\mathrm{mm}$ is achieved

A new and reliable culture system for superficial low-grade urothelial carcinoma of the bladder

Several bladder cancer culture systems have been developed in recent years. However, reports about successful primary cultures of superficial urothelial carcinomas (UC) are sparse. Based on the specific growth requirements of UC described previously, we developed a new and reliable culture system for superficial low-grade UC. Between November 2002 and April 2006, 64 primary cultures of bladder cancer specimens were performed. After incubating the specimens overnight in 0.1% ethylenediaminetetraacetic acid solution, tumour cells could easily be separated from the submucosal tissue. Subsequently, cells were seeded in a low-calcium culture medium supplemented with 1% serum, growth factors, non-essential amino acids and glycine. The malignant origin of the cultured cells was demonstrated by spectral karyotyping. Overall culture success rate leading to a homogenous tumour cell population without fibroblast contamination was 63%. Culture success could be remarkably enhanced by the addition of glycine to the culture medium. Interestingly, 86.4% of pTa tumours were cultured successfully compared to only 50% of the pT1 and 38% of advanced stage tumours, respectively. G1 and G2 tumours grew significantly better than G3 tumours (86, 73 and 41%, respectively). Up to three passages of low-grade UC primary cultures were possible. We describe a new and reliable culture system, which is highly successful for primary culture and passage of low-grade UC of the bladder. Therefore, this culture system can widely be used for functional experiments on early stage bladder cance

Der pathologische Exportboom: These und Stellungnahmen

Die deutsche Volkswirtschaft gibt Rätsel auf: Einerseits ist Deutschland Export-(Vize-)Weltmeister, andererseits leidet es unter einer anhaltenden Wachstums- und Beschäftigungsschwäche. Ist das Exportwachstum Ausdruck ungebrochener internationaler Wettbewerbsfähigkeit und die Wachstums- und Beschäftigungsschwäche nur ein konjunkturelles Problem, das sich einem Mangel an privater Binnennachfrage verdankt. Oder deutet das Nebeneinander von Wirtschaftskrise und Exportboom auf ein Standortproblem Deutschlands im Allgemeinen und ein Lohnproblem im Besonderen hin

Der pathologische Exportboom These und Stellungnahmen

Die deutsche Volkswirtschaft gibt Rätsel auf: Einerseits ist Deutschland Export-(Vize-)Weltmeister, andererseits leidet es unter einer anhaltenden Wachstums- und Beschäftigungsschwäche. Ist das Exportwachstum Ausdruck ungebrochener internationaler Wettbewerbsfähigkeit und die Wachstums- und Beschäftigungsschwäche nur ein konjunkturelles Problem, das sich einem Mangel an privater Binnennachfrage verdankt. Oder deutet das Nebeneinander von Wirtschaftskrise und Exportboom auf ein Standortproblem Deutschlands im Allgemeinen und ein Lohnproblem im Besonderen hin?Export, Lohn, Arbeitskosten, Beschäftigung, Wertschöpfung, Arbeitslosigkeit, Deutschland

Menschen entwickeln Qualitäten: Qualitätsmanagement nach dem GAB-Verfahren; ein Leitfaden für pädagogische und soziale Arbeitsfelder

Der Leitfaden beschreibt das Qualitätsmanagement in sozialen Organisationen mit dem GAB-Verfahren. Im Fokus steht die Beziehungsqualität als wesentliches Erfolgs- und Qualitätsmerkmal. Führungskräfte, Qualitätskoordinatoren und -beauftragte finden hier das methodische Handwerkszeug für ein vollständiges Qualitätsmanagement, das gleichzeitig Philosophie, Unternehmenskultur, Organisationsstruktur und tägliche Arbeit unterstützt. Das Konzept fördert eine wertschätzende Kommunikation, den konstruktiven Umgang mit Vielfalt und die Vertrauenskultur im Team. Ein Qualitätsmanagement auf der Grundlage des GAB-Verfahrens kann nach ISO 9001:2015, AZAV, ISO 29990 und anderen Vorgaben zertifiziert werden.The manual describes the quality management in social organisations using the GAB procedure. The emphasis is on relationship quality as an important characteristic for success and quality. Executives, quality coordinators and officers find the appropriate methodological tools for a comprehensive quality management, which at the same time supports company philosophy and culture, organisational structures and daily work routines. The concept promotes appreciative communication, constructive interaction with diversity and a culture of trust within a team. A quality management based on the GAB procedure can be certified in accordance with ISO 9001: 2015, AZAV, ISO 29990 and various other standards

CXCR4 and CXCR7 Mediate TFF3-Induced Cell Migration Independently From the ERK1/2 Signaling Pathway

Purpose: Trefoil factor family (TFF) peptides, and in particular TFF3, are characteristic secretory products of mucous epithelia that promote antiapoptosis, epithelial migration, restitution, and wound healing. For a long time, a receptor for TFF3 had not yet been identified. However, the chemokine receptor CXCR4 has been described as a low affinity receptor for TFF2. Additionally, CXCR7, which is able to heterodimerize with CXCR4, has also been discussed as a potential TFF2 receptor. Since there are distinct structural similarities between the three known TFF peptides, this study evaluated whether CXCR4 and CXCR7 may also act as putative TFF3 receptors. Methods: We evaluated the expression of both CXCR4 and CXCR7 in samples of human ocular surface tissues and cell lines, using RT-PCR, immunohistochemistry, and Western blot analysis. Furthermore, we studied possible binding interactions between TFF3 and the receptor proteins in an x-ray structure-based modeling system. Functional studies of TFF3–CXCR4/CXCR7 interaction were accomplished by cell culture–based migration assays, flow cytometry, and evaluation of activation of the mitogen-activated protein (MAP) kinase signaling cascade. Results: We detected both receptors at mRNA and protein level in all analyzed ocular surface tissues, and in lesser amount in ocular surface cell lines. X-ray structure-based modeling revealed CXCR4 and CXCR7 dimers as possible binding partners to TFF3. Cell culture–based assays revealed enhanced cell migration under TFF3 stimulation in a conjunctival epithelial cell line, which was completely suppressed by blocking CXCR4 and/or CXCR7. Flow cytometry showed increased proliferation rates after TFF3 treatment, while blocking both receptors had no effect on this increase. Trefoil factor family 3 also activated the MAP kinase signaling cascade independently from receptor activity. Conclusions: Dimers CXCR4 and CXCR7 are involved in TFF3-dependent activation of cell migration, but not cell proliferation. The ERK1/2 pathway is activated in the process, but not influenced by CXCR4 or CXCR7. These results implicate a dependence of TFF3 activity as to cell migration on the chemokine receptors CXCR4 and CXCR7 at the ocular surface