Influence of orbital symmetry on diffraction imaging with rescattering electron wave packets

Citation: Pullen, M. G., Wolter, B., Le, A. T., Baudisch, M., Sclafani, M., Pires, H., . . . Biegert, J. (2016). Influence of orbital symmetry on diffraction imaging with rescattering electron wave packets. Nature Communications, 7, 6. doi:10.1038/ncomms11922The ability to directly follow and time-resolve the rearrangement of the nuclei within molecules is a frontier of science that requires atomic spatial and few-femtosecond temporal resolutions. While laser-induced electron diffraction can meet these requirements, it was recently concluded that molecules with particular orbital symmetries (such as pi(g)) cannot be imaged using purely backscattering electron wave packets without molecular alignment. Here, we demonstrate, in direct contradiction to these findings, that the orientation and shape of molecular orbitals presents no impediment for retrieving molecular structure with adequate sampling of the momentum transfer space. We overcome previous issues by showcasing retrieval of the structure of randomly oriented O-2 and C2H2 molecules, with pi(g) and pi(u) symmetries, respectively, and where their ionization probabilities do not maximize along their molecular axes. While this removes a serious bottleneck for laser-induced diffraction imaging, we find unexpectedly strong backscattering contributions from low-Z atoms

Theory of extraordinary optical transmission through subwavelength hole arrays

We present a fully three-dimensional theoretical study of the extraordinary transmission of light through subwavelength hole arrays in optically thick metal films. Good agreement is obtained with experimental data. An analytical minimal model is also developed, which conclusively shows that the enhancement of transmission is due to tunneling through surface plasmons formed on each metal-dielectric interfaces. Different regimes of tunneling (resonant through a ''surface plasmon molecule", or sequential through two isolated surface plasmons) are found depending on the geometrical parameters defining the system.Comment: 4 pages, 4 figure

Impact Forecasting to Support Emergency Management of Natural Hazards

Forecasting and early warning systems are important investments to protect lives, properties, and livelihood. While early warning systems are frequently used to predict the magnitude, location, and timing of potentially damaging events, these systems rarely provide impact estimates, such as the expected amount and distribution of physical damage, human consequences, disruption of services, or financial loss. Complementing early warning systems with impact forecasts has a twofold advantage: It would provide decision makers with richer information to take informed decisions about emergency measures and focus the attention of different disciplines on a common target. This would allow capitalizing on synergies between different disciplines and boosting the development of multihazard early warning systems. This review discusses the state of the art in impact forecasting for a wide range of natural hazards. We outline the added value of impact-based warnings compared to hazard forecasting for the emergency phase, indicate challenges and pitfalls, and synthesize the review results across hazard types most relevant for Europe

Adaptation to flood risk: Results of international paired flood event studies

As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, that is, consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socioeconomic and hydro-climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, for example, via raised risk awareness, preparedness, and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur

Novel Patient Cell-Based HTS Assay for Identification of Small Molecules for a Lysosomal Storage Disease

Small molecules have been identified as potential therapeutic agents for lysosomal storage diseases (LSDs), inherited metabolic disorders caused by defects in proteins that result in lysosome dysfunctional. Some small molecules function assisting the folding of mutant misfolded lysosomal enzymes that are otherwise degraded in ER-associated degradation. The ultimate result is the enhancement of the residual enzymatic activity of the deficient enzyme. Most of the high throughput screening (HTS) assays developed to identify these molecules are single-target biochemical assays. Here we describe a cell-based assay using patient cell lines to identify small molecules that enhance the residual arylsulfatase A (ASA) activity found in patients with metachromatic leukodystrophy (MLD), a progressive neurodegenerative LSD. In order to generate sufficient cell lines for a large scale HTS, primary cultured fibroblasts from MLD patients were transformed using SV40 large T antigen. These SV40 transformed (SV40t) cells showed to conserve biochemical characteristics of the primary cells. Using a specific colorimetric substrate para-nitrocatechol sulfate (pNCS), detectable ASA residual activity were observed in primary and SV40t fibroblasts from a MLD patient (ASA-I179S) cultured in multi-well plates. A robust fluorescence ASA assay was developed in high-density 1,536-well plates using the traditional colorimetric pNCS substrate, whose product (pNC) acts as “plate fluorescence quencher” in white solid-bottom plates. The quantitative cell-based HTS assay for ASA generated strong statistical parameters when tested against a diverse small molecule collection. This cell-based assay approach can be used for several other LSDs and genetic disorders, especially those that rely on colorimetric substrates which traditionally present low sensitivity for assay-miniaturization. In addition, the quantitative cell-based HTS assay here developed using patient cells creates an opportunity to identify therapeutic small molecules in a disease-cellular environment where potentially disrupted pathways are exposed and available as targets

Generalized cerebral atrophy seen on MRI in a naturally exposed animal model for creutzfeldt-jakob disease

<p>Abstract</p> <p>Background</p> <p>Magnetic resonance imaging has been used in the diagnosis of human prion diseases such as sCJD and vCJD, but patients are scanned only when clinical signs appear, often at the late stage of disease. This study attempts to answer the questions "Could MRI detect prion diseases before clinical symptoms appear?, and if so, with what confidence?"</p> <p>Methods</p> <p>Scrapie, the prion disease of sheep, was chosen for the study because sheep can fit into a human sized MRI scanner (and there were no large animal MRI scanners at the time of this study), and because the USDA had, at the time of the study, a sizeable sample of scrapie exposed sheep, which we were able to use for this purpose. 111 genetically susceptible sheep that were naturally exposed to scrapie were used in this study.</p> <p>Results</p> <p>Our MRI findings revealed no clear, consistent hyperintense or hypointense signal changes in the brain on either clinically affected or asymptomatic positive animals on any sequence. However, in all 37 PrP^Scpositive sheep (28 asymptomatic and 9 symptomatic), there was a greater ventricle to cerebrum area ratio on MRI compared to 74 PrP^Scnegative sheep from the scrapie exposed flock and 6 control sheep from certified scrapie free flocks as defined by immunohistochemistry (IHC).</p> <p>Conclusions</p> <p>Our findings indicate that MRI imaging can detect diffuse cerebral atrophy in asymptomatic and symptomatic sheep infected with scrapie. Nine of these 37 positive sheep, including 2 one-year old animals, were PrP^Scpositive only in lymph tissues but PrP^Scnegative in the brain. This suggests either 1) that the cerebral atrophy/neuronal loss is not directly related to the accumulation of PrP^Scwithin the brain or 2) that the amount of PrP^Scin the brain is below the detectable limits of the utilized immunohistochemistry assay. The significance of these findings remains to be confirmed in human subjects with CJD.</p

Reporting of ethical approval and informed consent in clinical research published in leading nursing journals : a retrospective observational study

Background: Ethical considerations play a prominent role in the protection of human subjects in clinical research. To date the disclosure of ethical protection in clinical research published in the international nursing journals has not been explored. Our research objective was to investigate the reporting of ethical approval and informed consent in clinical research published in leading international nursing journals. Methods: This is a retrospective observational study. All clinical research published in the five leading international nursing journals from the SCI Journal Citation Reports between 2015 and 2017 were retrieved to evaluate for evidence of ethical review. Results: A total of 2041 citations have been identified from the contents of all the five leading nursing journals that were published between 2015 and 2017. Out of these, 1284 clinical studies have been included and text relating to ethical review has been extracted. From these, most of prospective clinical studies (87.5%) discussed informed consent. Only half of those (52.9%) reported that written informed consent had been obtained; few (3.6%) reported oral consent, and few (6.8%) used other methods such as online consent or completion and return of data collection (such as surveys) to denote assent. Notably, 36.2% of those did not describe the method used to obtain informed consent and merely described that “consent was obtained from participants or participants agreed to join in the research”. Furthermore, whilst most of clinical studies (93.7%) mentioned ethical approval; 92.5% of those stated the name of ethical committee and interestingly, only 37.1% of those mentioned the ethical approval reference. The rates of reporting ethical approval were different between different study type, country, and whether financial support was received (all P<0.05). Conclusion: The reporting of ethics in leading international nursing journals demonstrates progress, but improvement of the transparency and the standard of ethical reporting in nursing clinical research is required

Panta Rhei benchmark dataset: socio-hydrological data of paired events of floods and droughts

As the adverse impacts of hydrological extremes increase in many regions of the world, a better understanding of the drivers of changes in risk and impacts is essential for effective flood and drought risk management and climate adaptation. However, there is currently a lack of comprehensive, empirical data about the processes, interactions, and feedbacks in complex human–water systems leading to flood and drought impacts. Here we present a benchmark dataset containing socio-hydrological data of paired events, i.e. two floods or two droughts that occurred in the same area. The 45 paired events occurred in 42 different study areas and cover a wide range of socio-economic and hydro-climatic conditions. The dataset is unique in covering both floods and droughts, in the number of cases assessed and in the quantity of socio-hydrological data. The benchmark dataset comprises (1) detailed review-style reports about the events and key processes between the two events of a pair; (2) the key data table containing variables that assess the indicators which characterize management shortcomings, hazard, exposure, vulnerability, and impacts of all events; and (3) a table of the indicators of change that indicate the differences between the first and second event of a pair. The advantages of the dataset are that it enables comparative analyses across all the paired events based on the indicators of change and allows for detailed context- and location-specific assessments based on the extensive data and reports of the individual study areas. The dataset can be used by the scientific community for exploratory data analyses, e.g. focused on causal links between risk management; changes in hazard, exposure and vulnerability; and flood or drought impacts. The data can also be used for the development, calibration, and validation of sociohydrological models. The dataset is available to the public through the GFZ Data Services (Kreibich et al., 2023, https://doi.org/10.5880/GFZ.4.4.2023.001)