Graphene defect formation by extreme ultraviolet generated photoelectrons

We have studied the effect of photoelectrons on defect formation in graphene during extreme ultraviolet (EUV) irradiation. Assuming the major role of these low energy electrons, we have mimicked the process by using low energy primary electrons. Graphene is irradiated by an electron beam with energy lower than 80 eV. After e-beam irradiation, it is found that the D peak, I(D), appears in the Raman spectrum, indicating defect formation in graphene. The evolution of I(D)/I(G) follows the amorphization trajectory with increasing irradiation dose, indicating that graphene goes through a transformation from microcrystalline to nanocrystalline and then further to amorphous carbon. Further, irradiation of graphene with increased water partial pressure does not significantly change the Raman spectra, which suggests that, in the extremely low energy range, e-beam induced chemical reactions between residual water and graphene is not the dominant mechanism driving defect formation in graphene. Single layer graphene, partially suspended over holes was irradiated with EUV radiation. By comparing with the Raman results from e-beam irradiation, it is concluded that the photoelectrons, especially those from the valence band, contribute to defect formation in graphene during irradiation.Comment: appears in Journal of Applied Physics 201

Staat van infectieziekten in Nederland, 2013

In dit rapport wordt gelinked naar een bijlage: appendix150205001.De uitbraak van mazelen in 2013 was de meest in het oog springende infectieziekte van dat jaar. Dit blijkt uit de Staat van Infectieziekten in Nederland 2013, die inzicht geeft in ontwikkelingen van infectieziekten bij de Nederlandse bevolking. Daarnaast worden de ontwikkelingen in het buitenland beschreven die voor Nederland relevant zijn. Met deze jaarlijkse uitgave informeert het RIVM beleidsmakers van het ministerie van Volksgezondheid, Welzijn en Sport (VWS). Elk jaar komt in de Staat van Infectieziekten een thema aan bod; dit jaar is dat de hoeveelheid jaren in goede gezondheid die verloren gaan (ziektelast) door infectieziekten. Sommige infectieziekten, zoals maag-darminfecties, komen erg vaak voor maar veroorzaken over het algemeen geen ernstige klachten. Andere daarentegen, bijvoorbeeld tetanus, komen slechts zelden voor maar veroorzaken relatief veel sterfgevallen. Een gezondheidsmaat die deze aspecten van ziekten combineert is de Disability Adjusted Life Year (DALY). Voor 32 infectieziekten is de ziektelast in Nederland tussen 2007 en 2011 geschat. De gemiddelde jaarlijkse ziektelast voor de totale Nederlandse bevolking was het hoogst voor ernstige pneumokokkenziekte (9444 DALY's per jaar) en griep (8670 DALY's per jaar), die respectievelijk 16 en 15 procent van de totale ziektelast van alle 32 infectieziekten vertegenwoordigen. Na polio en difterie (0 gevallen in de onderzochte periode), werd de laagste ziektelast geschat voor rodehond op 0,14 DALY's per jaar. De ziektelast voor deze ziekten is zo laag dankzij het Rijksvaccinatieprogramma. De ziektelast per individu varieerde van 0,2 DALY's per honderd infecties voor giardiasis (diarree die wordt veroorzaakt door een parasiet), tot 5081 en 3581 DALY's per honderd infecties voor respectievelijk hondsdolheid en een variant van de ziekte van Creutzfeldt-Jakob. Voor alle ziektelaststudies geldt dat de resultaten afhankelijk zijn van de modelparameters en aannames, en van de beschikbaarheid van accurate gegevens over de mate waarin de ziekten voorkomen. Toch kunnen deze schattingen informatief zijn voor beleidsmakers binnen de gezondheidszorg om prioriteiten te kunnen aanbrengen in preventieve en andere maatregelen.The measles outbreak in 2013 was the most striking infectious disease of that year. This is demonstrated in the State of Infectious Diseases in the Netherlands 2013, which provides insight into infectious disease trends in the Dutch population. Developments in other countries that are relevant for the Netherlands are also described. This annual RIVM publication informs policy-makers from the Ministry of Health, Welfare and Sport (VWS). Every year the State of Infectious Diseases in the Netherlands publishes reports on a particular theme. This year's topic concerns the estimation of disease burden: how many years of health life are lost due to infectious diseases? Some infectious diseases, such as gastrointestinal infections, occur frequently in the population, but do not generally give rise to serious complaints. In contrast, other diseases, for example tetanus, occur rarely but may lead to a high risk of death. A summary measure of population health that combines the morbidity and premature mortality attributable to a disease in a single quantity is the Disability Adjusted Life Year (DALY). For 32 infectious diseases, we estimated the disease burden in the Netherlands between 2007 and2011. The highest average annual burden for the total Netherlands population was estimated for invasive pneumococcal disease (9444 DALYs per year) and influenza (8670 DALYs per year), which represent 16 and 15 percent, respectively, of the total burden of all 32 diseases considered. After poliomyelitis and diphtheria (no cases in the period investigated), the lowest burden was estimated for rubella, at 0.14 DALYs per year. The extremely low burden for these diseases is due to the National Immunization Programme. The disease burden per individual varied from 0.2 DALYs per 100 infections for giardiasis (diarrhea that is caused by a parasite), to 5081 and 3581 DALYs per 100 infections for rabies and variant Creutzfeldt-Jakob disease, respectively. As with all burden of disease studies, results depend on disease model parameters and assumptions and on the availability of accurate data on the incidence of infection. Nevertheless, estimates of disease burden can be informative for public health policy-makers regarding the prioritization of preventive and other measures.Ministerie van VW

Self-healing in B12P2 through Mediated Defect Recombination

Citation: Self-healing in B12P2 through Mediated Defect Recombination. S. P. Huber, E. Gullikson, C. D. Frye, J. H. Edgar, R. W. E. van de Kruijs, F. Bijkerk, and D. Prendergast. Chemistry of Materials 28 8415--8428 (2016) 10.1021/acs.chemmater.6b04075The icosahedral boride B12P2 has been reported to exhibit “self-healing” properties, after transmission electron microscopy recordings of sample surfaces, which were exposed to highly energetic particle beams, revealed little to no damage. In this work, employing calculations from first-principles within the density functional theory (DFT) framework, the structural characteristics of boron interstitial and vacancy defects in B12P2 are investigated. Using nudged elastic band simulations, the diffusion properties of interstitial and vacancy defects and their combination, in the form of Frenkel defect pairs, are studied. We find that boron icosahedra maintain their structural integrity even when in a degraded state in the presence of a vacancy or interstitial defect and that the diffusion activation energy for the recombination of an interstitial vacany pair can be as low as 3 meV, in line with the previously reported observation of “self-healing”

Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial

Objective To determine the effectiveness of increasing the dietary content of soluble fibre (psyllium) or insoluble fibre (bran) in patients with irritable bowel syndrome

Detection of defect populations in superhard semiconductor boron subphosphide B12P2 through X-ray absorption spectroscopy

Citation: Detection of defect populations in superhard semiconductor boron subphosphide B12P2 through X-ray absorption spectroscopy. S. P. Huber, E. Gullikson, J. Meyer-Ilse, C. D. Frye, J. H. Edgar, R. W. E. van de Kruijs, F. Bijkerk, and D. Prendergast J. Mater. Chem. A 5 5737--5749 (2017) 10.1039/c6ta10935gRecent theoretical work has shown for the first time how the experimentally observed property of “self-healing” of the superhard semiconductor boron subphosphide (B12P2) arises through a process of mediated defect recombination. Experimental verification of the proposed mechanism would require a method that can detect and distinguish between the various defect populations that can exist in B12P2. X-ray absorption near-edge spectroscopy (XANES) is such a method and in this work we present experimentally collected spectra of B12P2samples with varying crystalline qualities. By simulating the X-ray spectroscopic signatures of potential crystallographic point defects from first-principles within the density functional theory framework, the presence of defect populations can be determined through spectroscopic fingerprinting. Our results find an increasing propensity for the presence of phosphorus vacancy defects in samples deposited at lower temperatures but no evidence for comparable populations of boron vacancies in all the samples that have been studied. The absence of large amounts of boron vacancies is in line with the “self-healing” property of B12P2

SGLT2 inhibition promotes glomerular repopulation by cells of renin lineage in experimental kidney disease

Aim: Sodium glucose co-transporter-2 (SGLT2) inhibitors stimulate renal excretion of sodium and glucose and exert renal protective effects in patients with (non-)diabetic chronic kidney disease (CKD) and may as well protect against acute kidney injury (AKI). The mechanism behind this kidney protective effect remains unclear. Juxtaglomerular cells of renin lineage (CoRL) have been demonstrated to function as progenitors for multiple adult glomerular cell types in kidney disease. This study assesses the impact of SGLT2 inhibition on the repopulation of glomerular cells by CoRL and examines their phenotypic commitment. Methods: Experiments were performed in Ren1cre-tdTomato lineage-trace mice. Either 5/6 nephrectomy (5/6NX) modeling CKD or bilateral ischaemia reperfusion injury (bIRI) mimicking AKI was applied, while the SGLT2 inhibitor empagliflozin (10 mg/kg) was administered daily via oral gavage for 14 days. Results: Both 5/6NX and bIRI-induced kidney injury increased the number of glomerular CoRL-derived cells. SGLT2 inhibition improved kidney function after 5/6NX, indicated by decreased blood creatinine and urea levels, but not after bIRI. In line with this, empagliflozin in 5/6NX animals resulted in less glomerulosclerosis, while it did not affect histopathological features in bIRI. Treatment with empagliflozin resulted in an increase in the number of CoRL-derived glomerular cells in both 5/6NX and bIRI conditions. Interestingly, SGLT2 inhibition led to more CoRL-derived podocytes in 5/6NX animals, whereas empagliflozin-treated bIRI mice presented with increased levels of parietal epithelial and mesangial cells derived from CoRL. Conclusion: We conclude that SGLT2 inhibition by empagliflozin promotes CoRL-mediated glomerular repopulation with selective CoRL-derived cell types depending on the type of experimental kidney injury. These findings suggest a previously unidentified mechanism that could contribute to the renoprotective effect of SGLT2 inhibitors.</p

Relation between composition and fracture strength in off-stoichiometric metal silicide free-standing membranes

In this work, we investigated the influence of composition on the polycrystalline structure, elastic properties and fracture strength, of ZrxSi1-x, NbxSi1-x, and MoxSi1-x free-standing thin films that were deposited by magnetron sputtering and subsequently annealed at 500 °C. Despite deviations from the stoichiometric composition, the crystalline structure of all films, except for the most Zr-rich ZrxSi1-x, corresponded to their respective stoichiometric disilicide structures, without the formation of a second-phase. Off-stoichiometry was found to be accompanied by the presence of lattice defects and a decrease of the grain size, which bring about a lower tensile stress in the films. The dependence of the fracture strength on the composition was remarkably similar for the three silicides, with the lowest and highest strength values occurring for samples with 30% and 37–40% of metal content, respectively. The observed dependence of strength on composition was attributed to the combination of the Hall-Petch effect, changes in the morphology and strength of grain boundaries, and the enhancement of crystal plasticity due to lattice defects induced by off-stoichiometry