Field structure and electron life times in the MEFISTO Electron Cyclotron Resonance Ion Source

The complex magnetic field of the permanent-magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Bern have been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance at 2.45 GHz and 87.5 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. New results were obtained from the numerical simulation of 25211 electron trajectories. The evident characteristic ion sputtering trident of hexapole confined ECR sources has been identified with the field and electron trajectory distribution. Furthermore, unexpected long electron trajectory lifetimes were found.Comment: 11 pages, 18 figure

An investigation into the utility of the ImPACT neurocognitive screening tool with patients diagnosed with multiple sclerosis

Objective: The objective of this study was to investigate the utility of the Immediate Post Concussion Assessment and Cognitive Testing (ImPACT) assessment tool in the neurocognitive screening of patients with Multiple Sclerosis (MS). Participants and Method: Patients diagnosed with Multiple Sclerosis (n = 29) were compared with a healthy control group (n = 20) of equivalent age, years of education, quality of education and estimated premorbid IQ. Measures included five ImPACT composite scores, the ImPACT Design Memory Delayed Recall subtest, the Symbol Digit Modalities Test (SDMT) that has shown prior sensitivity to cognitive dysfunction in MS groups, and the SDMT Delayed Recall test. T-test analyses compared test performances of the MS patient group with the control group; correlational analyses investigated the construct similarities between the ImPACT and SDMT tests. Results: There was a consistent trend for the MS patient group to perform worse than controls on all the neurocognitive tests. Significant differences accompanied by medium to high effect sizes were in evidence for ImPACT Reaction Time, ImPACT Cognitive Efficiency Index, ImPACT Design Memory Delayed Recall, SDMT, and SDMT Delayed Recall test. Correlational analyses revealed construct comparability between the ImPACT tests calling upon processing speed and the SDMT, as well as the IMPACT and SDMT delayed recall tasks. Conclusions: The results support the utility of the ImPACT test as a screening instrument for the detection of cognitive dysfunction in patients with MS. Tests tapping general cognitive efficiency, processing speed, reaction time, and delayed recall rather than immediate recall reveal particular utility as neurocognitive screening aids for patients with MS

The wound healing effects of a 3 CH homeopathic solution of hypericum perforatum, calendula officinalis and echinacea purpurea combied with photobiomodulation on diabetic fibroblasts

Abstract: The skin is the largest organ in the human body and is prone to injury (Martin & Nunan, 2015). Wounds usually heal in a timely, well-regulated fashion by following a predictable sequence of events (Tsourdi et al., 2013). Chronic wounds, however, take longer than three months to heal, and display unique characteristics such as disrupted patterns of cytokine expression and a prolonged inflammatory phase which is detrimental (Martin & Nunan, 2015; Wetzler et al., 2000). Interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α) are both cytokines which indicate inflammation (Barrientos et al., 2008). Diabetes mellitus (DM) is an endocrine disorder that is reaching epidemic proportion and whose prevalence is increasing worldwide (Cho et al., 2018). In DM, chronic wounds called diabetic foot ulcers (DFUs) are a serious complication which often leads to lower limb amputations (Sohn et al., 2010). The treatment of DFUs is notoriously difficult and new therapies are urgently needed to decrease the burden on national health care systems (Cho et al., 2018). Homeopathy is a complementary health system which is effective in treating a variety of disease conditions (Fisher, 2012). The substances Calendula officinalis (C. officinalis), Hypericum perforatum (H. perforatum) and Echinacea purpurea (E. purpurea) effectively stimulates wound healing in herbal form (Parente et al., 2012; Samadi et al., 2010; Rezaie et al., 2013). These remedies are also indicated in the homeopathic literature for the treatment of wounds, however there are limited studies on their effectiveness (Hering, 1997; Boericke, 1999; Sinha, 1981). Photobiomodulation (PBM) is a therapeutic intervention which involves using lowintensity laser light at specific wavelengths to treat a variety of medical conditions (Andrade et al., 2014). PBM is effective in accelerating wound healing in a variety of experimental models, including DFU in DM (Carvalho et al., 2016; Kaviani et al., 2011). The aim of this study was to determine the effects of a 3 cH homeopathic solution containing C. officinalis, H. perforatum and E. purpurea and PBM, both as single therapies and in combination in an in vitro diabetic wounded cell model. v Commercially available human skin fibroblasts (WS1) were used as an in vitro model in this study. Normal cell models were grown in supplemented culture medium and diabetic cell models were grown in the same with additional glucose to generate a final glucose concentration of 22.6 mMol/L. Cells were sub-cultured at confluency in 3.4 cm diameter culture dishes and subjected to the ‘scratch assay’ (Felice et al., 2015) using a sterile pipette tip to simulate a wound. For the PBM models, cells were irradiated using laser light with a wavelength of 660 nm and a dose of 5 J/cm2 . This dose and wavelength is well established within the research centre, and has been shown to stimulate healing in this in vitro diabetic wounded model (Houreld et al., 2018; Ayuk et al., 2016; Jere et al., 2018). For homeopathically treated models a homeopathic solution containing 3 cH C. officinalis, H. perforatum and E. purpurea prepared in 5% ethanol was added to culture medium and incubated for 48 h. In cells treated with both these therapies, the homeopathic solution was added first and then plates were irradiated. Controls were nonwounded cells, and wounded cells that received neither of the treatments, as well as an alcohol control group where 5% ethanol was added to culture medium. Images were captured using a microscope (Olympus CKX41) coupled to a digital camera at 0 h, 24 h and 48 h after treatment to visualise cellular morphology. For biochemical assays, culture medium was collected 48 h post-treatment and cells were detached from culture plates. A proportion of the culture medium was frozen to perform the enzyme-linked immunosorbent assay (ELISA), and a proportion was used immediately to perform the lactate dehydrogenase (LDH) membrane integrity assay to determine cytotoxicity. Detached cells were used to perform the adenosine triphosphate (ATP) luminescence assay and the Trypan Blue exclusion assay, measures of cellular viability. ELISA was performed using commercially available kits to determine the concentration of proinflammatory cytokines IL-6 and TNF-α in culture medium. Morphological changes revealed that both PBM and the homeopathic solution stimulated wound healing in diabetic wounded cells, and that combining these therapies had an even greater effect. Cellular viability was not affected by either homeopathic solution or PBM but combining them caused increased viability as indicated by ATP results. Trypan Blue results revealed decreased viability, contradicting the ATP results. Cytotoxicity was decreased by the homeopathic solution complex and in the combination therapy group. TNF-α concentration remained unchanged with both PBM and homeopathic solution as vi single treatment interventions but combining them increased TNF-α concentration. PBM decreased IL-6 concentration, indicating an anti-inflammatory effect. These cellular changes indicate that combining PBM and a 3 cH solution containing C. officinalis, H. perforatum and E. purpurea holds potential for accelerating wound healing in the context of DFUs. Further research is necessary to establish effects in more complex models.M.Tech. (Homoeopathy

Surface analysis of Mercury with a mass-spectrometer

Introduction: The European Space Agency BepiColombo mission to Mercury will include a lander, the Mercury Surface Element (MSE). Although the final configuration of instruments is still to be decided, we are developing a mass spectrometer suitable for use on this lander, or in other missions where low mass and low power consumption are a priority. Advantages of a mass-spectrometer over other analytical instruments include sensitivity to almost all elements, high dynamic range, spatially resolved measurements (with an appropriate sampling technique) and the potential to determine isotopic compositions

Genetic Analysis of Germline Development in the Model Organism C. elegans

My research investigated the relationships among several transcriptional and/or post-transcriptional regulators in the C. elegans germ line. I examined the relationship between the rha-1 gene and three other regulatory genes, ego-1, glp-1 and csr-1. These genes function in germline proliferation and differentiation and are required for fertility. Because these genes regulate similar processes, we have investigated the relationships among them. The rha-1 gene encodes an RNA helicase that is required for germline development, chromatin regulation, and RNA interference (RNAi). The ego-1 gene encodes an RNA-directed RNA polymerase that is also required for these processes. Although many of the rha-1 and ego-1 defects are similar, the rha-1 null phenotype is temperature-sensitive (ts) whereas the ego-1 null phenotype is not. The glp-1 gene encodes a Notch-type receptor that receives an inductive signal from distal tip cell (DTC), which maintains germline proliferation. In the absence of GLP-1 signaling, germ cells that are normally mitotic instead enter meiosis and undergo gametogenesis. The csr-1 gene encodes an Argonaute-type RNA binding protein that is required for germline development and chromatin regulation. Mutations in ego-1 and csr-1 enhance the phenotype of a weak glp-1 mutation. We constructed double mutant strains carrying the rha-1 null allele and either a null allele of ego-1 or csr-1, or a ts allele of glp-1. Our data suggest that EGO-1 and RHA-1 proteins work together to regulate some aspects of development and in parallel to regulate others. Preliminary genetic data also suggest that CSR-1 and RHA-1 work together to regulate development, but act antagonistically to regulate oogenesis onset or a very early step in oogenesis. Additionally, our research suggests that RHA-1 does not regulate germline proliferation by promoting GLP-1 signaling. These findings have improved our understanding of how germline development is regulated in this model organism

Calibrating beam fluxes of a low-energy neutral atom beam facility.

Scientific detection and imaging instruments for low-energetic neutral atoms (ENA) onboard spacecraft require thorough pre-flight laboratory calibration against a well-characterized neutral atom beam source. To achieve this requirement, a dedicated test facility is available at the University of Bern, which is equipped with a powerful plasma ion source and an ion beam neutralization stage. Using surface neutralization, low-energy neutral atom beams of any desired gas species can be produced in the energy range from 3 keV down as low as 10 eV. As the efficiency of the neutralization stage is species and energy dependent, the neutralizer itself needs to be calibrated against an independent reference. We report on the calibration and characterization of this neutral atom beam source using our recently developed Absolute Beam Monitor (ABM) as a primary calibration standard. The ABM measures the absolute ENA flux independent of neutral species in the energy range from 10 eV to 3 keV. We obtain calibration factors of a few 100 cm-2 s-1 pA-1, depending on species at beam energies above about 100 eV, and a power-law decrease for energies below 100 eV. Furthermore, the energy loss of neutralized ions in the surface neutralizer is estimated from time-of-flight measurements using the ABM. The relative energy loss increases with ENA energy from low levels near zero up to 20%-35% at 3 keV, depending on atomic species. Having calibrated our neutral beam source allows for accurate calibration of ENA space instruments

Characteristics of proton velocity distribution functions in the near-lunar wake from Chandrayaan-1/SWIM observations

Due to the high absorption of solar wind plasma on the lunar dayside, a large scale wake structure is formed downstream of the Moon. However, recent in-situ observations have revealed the presence of protons in the near-lunar wake (100 km to 200 km from the surface). The solar wind, either directly or after interaction with the lunar surface (including magnetic anomalies), is the source of these protons in the near-wake region. Using the entire data from the SWIM sensor of the SARA experiment onboard Chandrayaan-1, we analysed the velocity distribution of the protons observed in the near-lunar wake. The average velocity distribution functions, computed in the solar wind rest frame, were further separated based on the angle between the upstream solar wind velocity and the IMF. Several proton populations were identified from the velocity distribution and their possible entry mechanism were inferred based on the characteristics of the velocity distribution. These entry mechanisms include (i) diffusion of solar wind protons into the wake along IMF, (ii) the solar wind protons with finite gyro-radii that are aided by the wake boundary electric field, (iii) solar wind protons with gyro-radii larger than lunar radii from the tail of the solar wind velocity distribution, and (iv) scattering of solar wind protons from the dayside lunar surface or from magnetic anomalies. In order to gain more insight into the entry mechanisms associated with different populations, backtracing is carried out for each of these populations. For most of the populations, the source of the protons obtained from backtracing is found to be in agreement with that inferred from the velocity distribution. There are few populations that could not be explained by the known mechanisms and remain unknown.Comment: 8 figures, paper accepted in Icarus (2016), http://dx.doi.org/10.1016/j.icarus.2016.01.03