DEPFET detectors for direct detection of MeV Dark Matter particles

The existence of dark matter is undisputed, while the nature of it is still unknown. Explaining dark matter with the existence of a new unobserved particle is among the most promising possible solutions. Recently dark matter candidates in the MeV mass region received more and more interest. In comparison to the mass region between a few GeV to several TeV, this region is experimentally largely unexplored. We discuss the application of a RNDR DEPFET semiconductor detector for direct searches for dark matter in the MeV mass region. We present the working principle of the RNDR DEPFET devices and review the performance obtained by previously performed prototype measurements. The future potential of the technology as dark matter detector is discussed and the sensitivity for MeV dark matter detection with RNDR DEPFET sensors is presented. Under the assumption of three background events in the region of interest and an exposure of one kg$\cdot$y a sensitivity of $\bar{\sigma}_{\bar{e}} = 10^{-41}$ cm$^{2}$ for dark matter particles with a mass of 10 MeV can be reached.Comment: submitted to EPJ

Editorial: Silicon radiation detectors: Status and perspectives

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Antimikrobna aktivnost i fenolni sastav ekstrakta biljke Salvia Verticillata L.

The aim of this study was to investigatethe total content of phenolic compounds, flavonoids and phenolic acids,examine the antimicrobial activity of the methanolic extract of S. verticillata aerial part, and demonstrate the presence of rosmarinic acid. The extract was rich in total phenolic content, especially in the total flavonoids content. Using the thin layer chromatography method, rosmarinic acid was identified in the extract.The extract showed moderate to weak antibacterial activity with MIC values of 1.25 to 20 mg/mL and significantly lower antifungal activity. The obtained results suggest that S. verticillata could be subjected to further studies of its pharmacological potential.Cilj ovog rada je bio određivanje ukupne količine fenolnih jedinjenja, flavonoida i fenolnih kiselina, ispitivanje antimikrobne aktivnosti metanolnog ekstrakta nadzemnog dela biljke S. verticillata, kao i dokazivanje prisustva ruzmarinske kiseline. Ekstrakt je sadržao značajnu količinu ukupnih fenolnih jedinjenja, pri čemu se izdvojio po visokom sadržaju flavonoida.TLC hromatografijom pokazano je prisustvo ruzmarinske kiseline u ovom ekstraktu. Ekstrakt je pokazao umerenu do slabu antibakterijsku aktivnost sa MIK vrednostima od 1,25 do 20 mg/mLi znatno slabiju antifungalnu aktivnost. Dobijeni rezultati sugerišu da se mogu nastaviti dalja ispitivanja farmakološkog potncijala biljkeS. verticillata

Different levels of humoral immunoreactivity to different wheat cultivars gliadin are present in patients with celiac disease and in patients with multiple myeloma

<p>Abstract</p> <p>Background</p> <p>Immunity to food antigens (gliadin, cow's milk proteins) is in the centre of the attention of modern medicine focused on the prevention of diseases, prevention which is based on the use of appropriate restriction diet. Detection of the enhanced levels of the immune reactions to antigen(s) present in food is from this point of view of great importance because there are reports that some of health disturbances, like celiac disease (CD) and some premalignant conditions, like monoclonal gammopathy of undetermined significance (MGUS), were vanished after the appropriate restriction diets.</p> <p>It is well known that gliadin is toxic to small bowel mucosa of relatively small population of genetically predisposed individuals, who under this toxic action develop celiac disease (CD). As the quantity of immunogenic gliadin could vary between different wheat species, the first aim of this work was to determine the percentage of immunogenic gliadin in ten bread wheat cultivars and in three commercially grown durum wheat cultivars. The second part of the study was initiated by results of previous publication, reporting that sera of some of multiple myeloma (MM) patients showed the presence of elevated levels of anti-gliadin IgA, without the enhanced levels of anti-gliadin IgG antibodies, determined with commercial ELISA test. It was designed to assess is it possible to reveal is there any hidden, especially anti-gliadin IgG immunoreactivity, in serum of mentioned group of patients. For this purpose we tested MM patients sera, as well as celiac disease (CD) patients sera for the immunoreaction with the native gliadin isolated from wheat species used for bread and pasta making in corresponding geographic region.</p> <p>Results</p> <p>Gliadin was isolated from wheat flour by two step 60% ehanolic extraction. Its content was determined by commercial R5 Mendez Elisa using PWG gliadin as the standard. Results obtained showed that immunogenic gliadin content varies between 50.4 and 65.4 mg/g in bread wheat cultivars and between 20 and 25.6 mg/g in durum wheat cultivars.</p> <p>Anti-gliadin IgA and IgG immunoreactivity of patients' sera in (IU/ml) was firstly determined by commercial diagnostic Binding Site ELISA test, and then additionally by non-commercial ELISA tests, using standardized ethanol wheat extracts -gliadin as the antigen.</p> <p>In both patients groups IgA immunoreactivity to gliadin from different cultivars was almost homogenous and in correlation with results from commercial test (except for one patient with IgA(λ) myeloma, they were more then five times higher). But, results for IgG immunoreactivity were more frequently inhomogeneous, and especially for few MM patients, they were more then five times higher and did not correlate with results obtained using Binding Site test.</p> <p>Conclusion</p> <p>Results obtained showed different content of immunogenic gliadin epitopes in various species of wheat.</p> <p>They also point for new effort to elucidate is there a need to develop new standard antigen, the representative mixture of gliadin isolated from local wheat species used for bread production in corresponding geographic region for ELISA diagnostic tests.</p

Status of the BELLE II Pixel Detector

The Belle II experiment at the super KEK B-factory (SuperKEKB) in Tsukuba, Japan, has been collecting $e^+e^−$ collision data since March 2019. Operating at a record-breaking luminosity of up to $4.7×10^{34} cm^{−2}s^{−1}$, data corresponding to $424 fb^{−1}$ has since been recorded. The Belle II VerteX Detector (VXD) is central to the Belle II detector and its physics program and plays a crucial role in reconstructing precise primary and decay vertices. It consists of the outer 4-layer Silicon Vertex Detector (SVD) using double sided silicon strips and the inner two-layer PiXel Detector (PXD) based on the Depleted P-channel Field Effect Transistor (DePFET) technology. The PXD DePFET structure combines signal generation and amplification within pixels with a minimum pitch of $(50×55) μm^2$. A high gain and a high signal-to-noise ratio allow thinning the pixels to $75 μm$ while retaining a high pixel hit efficiency of about $99$. As a consequence, also the material budget of the full detector is kept low at $≈0.21$$\frac{X}{X_0}$ per layer in the acceptance region. This also includes contributions from the control, Analog-to-Digital Converter (ADC), and data processing Application Specific Integrated Circuits (ASICs) as well as from cooling and support structures. This article will present the experience gained from four years of operating PXD; the first full scale detector employing the DePFET technology in High Energy Physics. Overall, the PXD has met the expectations. Operating in the intense SuperKEKB environment poses many challenges that will also be discussed. The current PXD system remains incomplete with only 20 out of 40 modules having been installed. A full replacement has been constructed and is currently in its final testing stage before it will be installed into Belle II during the ongoing long shutdown that will last throughout 2023

Study of detection efficiency distribution and areal homogeneity of SiPMs

The analog hadron calorimeter for the International Linear Collider (ILC) of the CALICE collaboration utilized novel silicon detectors, the Sillicon Photomultipliers (SiPMs), for the detection of scintillation light coming from very small scintillator cells 3x3x0.5 cm^3. This technology allows the construction of highly granular calorimeters used for excellent shower separation and therefore outstanding jet energy resolution using the particle flow concept. Since the SiPMs still have potential for further improvements, we developed a setup dedicated to the measurement of parameters like the areal distribution of relative photon detection efficiency and crosstalk probability which are used to characterize and compare different devices. Thanks to the precise positioning system together with excellent focusing of the light source we are capable of scanning whole SiPMs with an area of ca. 1 mm^2 at a sub-pixel resolution of 1-2 \mu{}m. A further alignment compensation feature allows us to conduct separate analysis on each single pixel of a SiPM. We present the technical description of our measurement setup and results obtained for two types of SiPMs. The first one is a commercial Hamamatsu MPPC with 50 \mu{}m pixel size, the second one was the second iteration series SiMPl device developed and manufactured in the Semiconductor Laboratory of the Max Planck Institute

Intermittent theta burst stimulation attenuates oxidative stress and reactive astrogliosis in the streptozotocin-induced model of Alzheimer’s disease-like pathology

IntroductionIntracerebroventricularly (icv) injected streptozotocin (STZ) is a widely used model for sporadic Alzheimer’s disease (sAD)-like pathology, marked by oxidative stress-mediated pathological progression. Intermittent theta burst stimulation (iTBS) is a noninvasive technique for brain activity stimulation with the ability to induce long-term potentiation-like plasticity and represents a promising treatment for several neurological diseases, including AD. The present study aims to investigate the effect of the iTBS protocol on the animal model of STZ-induced sAD-like pathology in the context of antioxidant, anti-inflammatory, and anti-amyloidogenic effects in the cortex, striatum, hippocampus, and cerebellum.MethodsMale Wistar rats were divided into four experimental groups: control (icv normal saline solution), STZ (icv STZ—3 mg/kg), STZ + iTBS (STZ rats subjected to iTBS protocol), and STZ + Placebo (STZ animals subjected to placebo iTBS noise artifact). Biochemical assays and immunofluorescence microscopy were used to evaluate functional and structural changes.ResultsThe icv STZ administration induces oxidative stress and attenuates antioxidative capacity in all examined brain regions. iTBS treatment significantly reduced oxidative and nitrosative stress parameters. Also, iTBS decreased Aβ-1-42 and APP levels. The iTBS enhances antioxidative capacity reported as elevated activity of its enzymatic and non-enzymatic components. In addition, iTBS elevated BDNF expression and attenuated STZ-induced astrogliosis confirmed by decreased GFAP+/VIM+/C3+ cell reactivity in the hippocampus.DiscussionOur results provide experimental evidence for the beneficial effects of the applied iTBS protocol in attenuating oxidative stress, increasing antioxidant capacity and decreasing reactive astrogliosis in STZ-administrated rats

Sustained Systemic Antioxidative Effects of Intermittent Theta Burst Stimulation beyond Neurodegeneration: Implications in Therapy in 6-Hydroxydopamine Model of Parkinson’s Disease

Parkinson’s disease (PD) is manifested by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and caudoputamen (Cp), leading to the development of motor and non-motor symptoms. The contribution of oxidative stress to the development and progression of PD is increasingly recognized. Experimental models show that strengthening antioxidant defenses and reducing pro-oxidant status may have beneficial effects on disease progression. In this study, the neuroprotective potential of intermittent theta burst stimulation (iTBS) is investigated in a 6-hydroxydopamine (6-OHDA)-induced PD model in rats seven days after intoxication which corresponds to the occurrence of first motor symptoms. Two-month-old male Wistar rats were unilaterally injected with 6-OHDA to mimic PD pathology and were subsequently divided into two groups to receive either iTBS or sham stimulation for 21 days. The main oxidative parameters were analyzed in the caudoputamen, substantia nigra pars compacta, and serum. iTBS treatment notably mitigated oxidative stress indicators, simultaneously increasing antioxidative parameters in the caudoputamen and substantia nigra pars compacta well after 6-OHDA-induced neurodegeneration process was over. Serum analysis confirmed the systemic effect of iTBS with a decrease in oxidative markers and an increase in antioxidants. Prolonged iTBS exerts a modulatory effect on oxidative/antioxidant parameters in the 6-OHDA-induced PD model, suggesting a potential neuroprotective benefit, even though at this specific time point 6-OHDA-induced oxidative status was unaltered. These results emphasize the need to further explore the mechanisms of iTBS and argue in favor of considering it as a therapeutic intervention in PD and related neurodegenerative diseases