17 research outputs found
SiC Based Beam Monitoring System for Particle Rates from kHz to GHz
The extremely low dark current of silicon carbide (SiC) detectors, even after
high-fluence irradiation, was utilized to develop a beam monitoring system for
a wide range of particle rates, i.e., from the kHz to the GHz regime. The
system is completely built from off-the-shelve components and is focused on
compactness and simple deployment. Beam tests using a 50 um thick SiC detector
reveal, that for low fluences, single particles can be detected and counted.
For higher fluences, beam properties were extracted from beam cross sections
using a silicon strip detector. Overall accurate results were achieved up to a
particle rate of 109 particles per second
Performance of neutron-irradiated 4H-Silicon Carbide diodes subjected to Alpha radiation
The unique electrical and material properties of 4H-silicon-carbide (4H-SiC)
make it a promising candidate material for high rate particle detectors. In
contrast to the ubiquitously used silicon (Si), 4H-SiC offers a higher carrier
saturation velocity and larger breakdown voltage, enabling a high intrinsic
time resolution and mitigating pile-up effects. Additionally, as radiation
hardness requirements grow more demanding, wide-bandgap materials such as
4H-SiC could offer better performance. In this work, the detector performance
of 50 micron thick 4H-SiC p-in-n planar pad sensors was investigated at room
temperature, using an 241Am alpha source at reverse biases of up to 1100 V.
Samples subjected to neutron irradiation with fluences of up to 1e16/cm^2 were
included in the study in order to quantify the radiation hardness properties of
4H-SiC. The obtained results are compared to previously performed UV-TCT
studies. Samples exhibit a drop in charge collection efficiency (CCE) with
increasing irradiation fluence, partially compensated at high reverse bias
voltages far above full depletion voltage. A plateau of the collected charges
is observed in accordance with the depletion of the volume the alpha particles
penetrate for an unirradiated reference detector. For the neutron-irradiated
samples, such a plateau only becomes apparent at higher reverse bias. For the
highest investigated fluence, CCE behaves almost linearly with increasing
reverse bias. Compared to UV-TCT measurements, the reverse bias required to
deplete a sensitive volume covering full energy deposition is lower, due to the
small penetration depth of the alpha particles. At the highest reverse bias,
the measured CCE values agree well with earlier UV-TCT studies, with
discrepancies between 1% and 5%.Comment: 10 pages (8 without references), 6 figures, 1 table, to be published
in the Proceedings Section of Journal of Instrumentation (JINST) as a
proceeding of iWoRiD202
Randomized controlled phase 2 trial of hydroxychloroquine in childhood interstitial lung disease
Background
No results of controlled trials are available for any of the few treatments offered to children with interstitial lung diseases (chILD). We evaluated hydroxychloroquine (HCQ) in a phase 2, prospective, multicentre, 1:1-randomized, double-blind, placebo-controlled, parallel-group/crossover trial. HCQ (START arm) or placebo were given for 4 weeks. Then all subjects received HCQ for another 4 weeks. In the STOP arm subjects already taking HCQ were randomized to 12 weeks of HCQ or placebo (= withdrawal of HCQ). Then all subjects stopped treatment and were observed for another 12 weeks.
Results
26 subjects were included in the START arm, 9 in the STOP arm, of these four subjects participated in both arms. The primary endpoint, presence or absence of a response to treatment, assessed as oxygenation (calculated from a change in transcutaneous O 2 -saturation of ≥ 5%, respiratory rate ≥ 20% or level of respiratory support), did not differ between placebo and HCQ groups. Secondary endpoints including change of O 2 -saturation ≥ 3%, health related quality of life, pulmonary function and 6-min-walk-test distance, were not different between groups. Finally combining all placebo and all HCQ treatment periods did not identify significant treatment effects. Overall effect sizes were small. HCQ was well tolerated, adverse events were not different between placebo and HCQ.
Conclusions
Acknowledging important shortcomings of the study, including a small study population, the treatment duration, lack of outcomes like lung function testing below age of 6 years, the small effect size of HCQ treatment observed requires careful reassessments of prescriptions in everyday practice (EudraCT-Nr.: 2013-003714-40, www.clinicaltrialsregister.eu , registered 02.07.2013)
Gene Expression Changes in the Prefrontal Cortex, Anterior Cingulate Cortex and Nucleus Accumbens of Mood Disorders Subjects That Committed Suicide
Suicidal behaviors are frequent in mood disorders patients but only a subset of them ever complete suicide. Understanding predisposing factors for suicidal behaviors in high risk populations is of major importance for the prevention and treatment of suicidal behaviors. The objective of this project was to investigate gene expression changes associated with suicide in brains of mood disorder patients by microarrays (Affymetrix HG-U133 Plus2.0) in the dorsolateral prefrontal cortex (DLPFC: 6 Non-suicides, 15 suicides), the anterior cingulate cortex (ACC: 6NS, 9S) and the nucleus accumbens (NAcc: 8NS, 13S). ANCOVA was used to control for age, gender, pH and RNA degradation, with P≤0.01 and fold change±1.25 as criteria for significance. Pathway analysis revealed serotonergic signaling alterations in the DLPFC and glucocorticoid signaling alterations in the ACC and NAcc. The gene with the lowest p-value in the DLPFC was the 5-HT2A gene, previously associated both with suicide and mood disorders. In the ACC 6 metallothionein genes were down-regulated in suicide (MT1E, MT1F, MT1G, MT1H, MT1X, MT2A) and three were down-regulated in the NAcc (MT1F, MT1G, MT1H). Differential expression of selected genes was confirmed by qPCR, we confirmed the 5-HT2A alterations and the global down-regulation of members of the metallothionein subfamilies MT 1 and 2 in suicide completers. MTs 1 and 2 are neuro-protective following stress and glucocorticoid stimulations, suggesting that in suicide victims neuroprotective response to stress and cortisol may be diminished. Our results thus suggest that suicide-specific expression changes in mood disorders involve both glucocorticoids regulated metallothioneins and serotonergic signaling in different regions of the brain
A device for simulating network cable failure : development of hardware to simulate typical failures of a 100base-TX network cable remote- and automatable
Zsfassung in dt. SpracheÜbliche 100 Mbit-Netzwerkkabel (100baseTX) haben genaue spezifizierte Betriebsparameter, innerhalb derer sie betrieben werden sollen. In dieser Arbeit wird gezeigt, welche Auswirkungen es auf Datenübertragungen haben kann, wenn solche Parameter nicht eingehalten werden, also beispielsweise Wackelkontakte oder Übergangswiderstände auftreten, unterschiedliche Kabelqualitäten (ohne, mit einfacher, mit doppelter Schirmung) verwendet werden und Ähnliches. Es werden die Auswirkungen verschiedener Kabelfehler auf Datenübertragungen untersucht, indem Modelle von Kabelfehlern erstellt werden und diese dann durch elektronische Schaltungen realisiert werden, über die Daten übertragen werden. Das Ergebnis sind Erkenntnisse und Kennlinienfelder, in denen die Übertragungsfehler einer Datenübertragung in einer Testumgebung in Abhängigkeit von verschieden schwerwiegenden Kabelfehlern dargestellt sind. Außerdem wird ein Gerät entwickelt und gebaut, das in ein Kabel geschaltet zahlreiche Kabelfehler erzeugen kann: falsch verdrahtete Leitungen, Kurzschlüsse, ohmsche, kapazitive und induktive Kabelfehler, Antennen, sowie beliebige Kombinationen aus mehreren dieser Fehler gleichzeitig. Dieser Linkcutter ist vollständig fernkonfigurierbar und sowohl interaktiv als auch vorprogrammiert bedienbar.Regular 100 Mbit-network cables (100baseTX) have strictly specified operating parameters in which they should operate. This work examines the consequences for data transmission when such parameters are violated. For example, if there are slack joints or resistances, or if different cable types (without, with single or with double shielding) are used. The consequences of different cable failures on data transmission are investigated. Therefore models of cable failures are created. These models are implemented as electronic circuits, and tested by transmitting data over the line. The results are data sets and characteristic curves, in which the errors of data transmissions in a test bed are shown in dependency of the severity of different cable failures. Moreover, a device is developed and built, which can be connected in series of a network cable and which can generate a lot of representative cable failures: wrong wired cables, short circuits, ohmic, capacitive and inductive cable faults and antennas, as well as any combination of them simultaneously. This Linkcutter is completely remote-controllable and configurable, and it is useable both interactively and pre-programmed.15
Interleukin-10 enhances recruitment of immune cells in the neonatal mouse model of obstructive nephropathy
Abstract Urinary tract obstruction during renal development leads to inflammation, leukocyte infiltration, tubular cell death, and interstitial fibrosis. Interleukin-10 (IL-10) is an anti-inflammatory cytokine, produced mainly by monocytes/macrophages and regulatory T-cells. IL-10 inhibits innate and adaptive immune responses. IL-10 has a protective role in the adult model of obstructive uropathy. However, its role in neonatal obstructive uropathy is still unclear which led us to study the role of IL-10 in neonatal mice with unilateral ureteral obstruction (UUO). UUO serves as a model for congenital obstructive nephropathies, a leading cause of kidney failure in children. Newborn Il-10 −/− and C57BL/6 wildtype-mice (WT) were subjected to complete UUO or sham-operation on the 2nd day of life. Neonatal kidneys were harvested at day 3, 7, and 14 of life and analyzed for different leukocyte subpopulations by FACS, for cytokines and chemokines by Luminex assay and ELISA, and for inflammation, programmed cell death, and fibrosis by immunohistochemistry and western blot. Compared to WT mice, Il-10 −/− mice showed reduced infiltration of neutrophils, CD11bhi cells, conventional type 1 dendritic cells, and T-cells following UUO. Il-10 −/− mice with UUO also showed a reduction in pro-inflammatory cytokine and chemokine release compared to WT with UUO, mainly of IP-10, IL-1α, MIP-2α and IL-17A. In addition, Il-10 −/− mice showed less necroptosis after UUO while the rate of apoptosis was not different. Finally, α-SMA and collagen abundance as readout for fibrosis were similar in Il-10 −/− and WT with UUO. Surprisingly and in contrast to adult Il-10 −/− mice undergoing UUO, neonatal Il-10 −/− mice with UUO showed a reduced inflammatory response compared to respective WT control mice with UUO. Notably, long term changes such as renal fibrosis were not different between neonatal Il-10 −/− and neonatal WT mice with UUO suggesting that IL-10 signaling is different in neonates and adults with UUO
Development of a data acquisition system for the Belle II silicon vertex detector
The silicon-strip vertex detector in the Belle II experiment is one of essential detectors to search for physics beyond the Standard Model. To read out all 223,744 readout strips of the double-sided silicon strip detectors in high beam background, 1748 APV25 chips are employed for the frontend electronics. Hence, flash analog-to-digital conversion with high-density inputs is required on the back-end electronics. We developed prototypes of the back-end electronics and successfully performed a full integration test at the DESY electron beam line. In this paper, we report on the development of the prototypes and results from the beam test
Performance of the Belle II Silicon Vertex Detector
The Belle II experiment at the SuperKEKB collider of KEK (Japan) will accumulate 50 ab−1 of e+e− collision data at an unprecedented instantaneous luminosity of 8 ×1035 cm−2s−1, about 40 times larger than its predecessor. The Belle II vertex detector plays a crucial role in the rich Belle II physics program, especially for time-dependent measurements. It consists of two layers of DEPFET-based pixels and four layers of double sided silicon strips detectors(SVD). The vertex detector has been recently completed and installed in Belle II for the physics run started in spring 2019. We report here results on the commissioning of the SVD and its performance measured with the first collision data set
Machine learning: hit time finding with a neural network
At the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, the double-sided silicon strip sub-detector of the Belle II experiment is read out by 1748 APV25 chips. FPGAs perform several calculations on the digitized signals. One of them will be "Hit Time Finding": the determination of the time and amplitude of the signal peaks of each event in real time using pre-programmed neural networks. This work analyses the possibility, precision and reliability of these calculations depending on various parameters