1,886 research outputs found
Comparison of two models for bridge-assisted charge transfer
Based on the reduced density matrix method, we compare two different
approaches to calculate the dynamics of the electron transfer in systems with
donor, bridge, and acceptor. In the first approach a vibrational substructure
is taken into account for each electronic state and the corresponding states
are displaced along a common reaction coordinate. In the second approach it is
assumed that vibrational relaxation is much faster than the electron transfer
and therefore the states are modeled by electronic levels only. In both
approaches the system is coupled to a bath of harmonic oscillators but the way
of relaxation is quite different. The theory is applied to the electron
transfer in with free-base porphyrin () being the donor, zinc porphyrin () being the bridge and
quinone () the acceptor. The parameters are chosen as similar as
possible for both approaches and the quality of the agreement is discussed.Comment: 12 pages including 4 figures, 1 table, 26 references. For more info
see http://eee.tu-chemnitz.de/~kili
Anterior Mediastinal Mass in a Young Marijuana Smoker: A Rare Case of Small-Cell Lung Cancer
The use of cannabis is embedded within many societies, mostly used by the young and widely perceived to be safe. Increasing concern regarding the potential for cannabis to cause mental health effects has dominated cannabis research, and the potential adverse respiratory effects have received relatively little attention. We report a rare case of 22-year-old man who presented with bilateral neck lymphadenopathy, fatigue, and sore throat without significant medical or family history. The patient had smoked one marijuana joint three times a week for three years but no cigarettes. Chest CT demonstrated a large anterior mediastinal mass compressing the superior vena cava and mediastinal lymphadenopathy. A final diagnosis of small-cell lung cancer was reached. Although rare, a small-cell lung cancer in this patient should alert the physician that cannabis smoking may be a risk factor for lung cancer
Economic and environmental assessments to support the decision making process in the offshore wind farm decommissioning projects
Open Access via the Elsevier agreement Funding This work was supported by the DecomTools project funded by the European Commission under the Interreg VB North Sea Region Programme [Project No.: 20180305091606]Peer reviewedPublisher PD
Drought Reduces Release of Plant Matter Into Dissolved Organic Matter Potentially Restraining Ecosystem Recovery
Future climate scenarios indicate increasing drought intensity that threatens ecosystem functioning. However, the behavior of ecosystems during intense drought, such as the 2018 drought in Northern Europe, and their respective response following rewetting is not fully understood. We investigated the effect of drought on four different vegetation types in a temperate climate by analyzing dissolved organic matter (DOM) concentration and composition present in soil leachate, and compared it to two accompanying years. DOM is known to play an important role in ecosystem recovery and holds information on matter flows between plants, soil microorganisms and soil organic matter. Knowledge about DOM opens the possibility to better disentangle the role of plants and microorganisms in ecosystem recovery. We found that the average annual DOM concentration significantly decreased during the 2018 drought year compared to the normal year. This suggests a stimulation of DOM release under normal conditions, which include a summer drought followed by a rewetting period. The rewetting period, which holds high DOM concentrations, was suppressed under more intense drought. Our detailed molecular analysis of DOM using ultrahigh resolution mass spectrometry showed that DOM present at the beginning of the rewetting period resembles plant matter, whereas in later phases the DOM molecular composition was modified by microorganisms. We observed this pattern in all four vegetation types analyzed, although vegetation types differed in DOM concentration and composition. Our results suggest that plant matter drives ecosystem recovery and that increasing drought intensity may lower the potential for ecosystem recovery
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Dont die like me: Which proteins are responsible for the selective neuronal vulnerability within the substantia nigra?
A hallmark of Parkinsons disease is the specific degeneration of dopaminergic neurons in the substantia nigra pars compacta. Interestingly, not all of these neurons are affected to the same extent. Studies revealed that neurons located more ventrally within the substantia nigra pars compacta have a higher prevalence to degenerate than those located in the dorsal tier. The underlying reasons for this selective neuronal vulnerability are still unknown. The aim of the present study was to gain a better understanding of molecular differences between these two neuronal subpopulations that may explain the selective neuronal vulnerability within the human substantia nigra. For this purpose, the neurons from the ventral as well as dorsal tier of the substantia nigra were specifically isolated out of neuropathologically unremarkable human substantia nigra sections with laser microdissection. Following, their proteome was analyzed by data independent acquisition mass spectrometry. The samples were analysed donor-specifically and not pooled for this purpose. A total of 5,391 proteins were identified in the substantia nigra. Of these, 2,453 proteins could be quantified in 100% of the dorsal tier samples. 1,629 could be quantified in 100% of the ventral tier samples. Nine proteins were differentially regulated with a log2 value â„0.5 and a Qvalue â€0.05. Of these 7 were higher abundant in the dorsal tier and 2 higher in the ventral tier. These proteins are associated with the cytoskeleton, neuronal plasticity, or calcium homeostasis. With these findings a deeper understanding can be gained of the selective neuronal vulnerability within the substantia nigra and of protective mechanisms against neurodegeneration in specific neuronal subpopulations
Leaky McEliece: Secret Key Recovery From Highly Erroneous Side-Channel Information
The McEliece cryptosystem is a strong contender for post-quantum schemes, including key encapsulation for confidentiality of key exchanges in network protocols.
A McEliece secret key is a structured parity check matrix that is transformed via Gaussian elimination into an unstructured public key. We show that this transformation is a highly critical operation with respect to side-channel leakage.
We assume leakage of the elementary row operations during Gaussian elimination, motivated by actual implementations of McEliece in real world cryptographic libraries (Classic McEliece and Botan).
We propose a novel algorithm to reconstruct a secret key from its public key with information from a Gaussian transformation leak. Even if the obtained side-channel leakage is extremely noisy, i.e., each bit can be flipped with probability as high as , our algorithm still succeeds to recover the secret key in a matter of minutes for all proposed (Classic) McEliece instantiations. Remarkably, for high-security McEliece parameters, our attack is more powerful in the sense that it can tolerate even larger .
Technically, we introduce a novel cryptanalytic decoding technique that exploits the high redundancy exhibited in the McEliece secret key. This allows our decoding routine to succeed in reconstructing each column of the secret key successively.
Our result stresses the necessity to well protect highly structured code-based schemes such as McEliece against side-channel leakage
Resolving physical interactions between bacteria and nanotopographies with focused ion beam scanning electron microscopy
To robustly assess the antibacterial mechanisms of nanotopographies, it is critical to analyze the bacteria-nanotopography adhesion interface. Here, we utilize focused ion beam milling combined with scanning electron microscopy to generate three-dimensional reconstructions of Staphylococcus aureus or Escherichia coli interacting with nanotopographies. For the first time, 3D morphometric analysis has been exploited to quantify the intrinsic contact area between each nanostructure and the bacterial envelope, providing an objective framework from which to derive the possible antibacterial mechanisms of synthetic nanotopographies. Surfaces with nanostructure densities between 36 and 58 per ÎŒm(2) and tip diameters between 27 and 50Â nm mediated envelope deformation and penetration, while surfaces with higher nanostructure densities (137 per ÎŒm(2)) induced envelope penetration and mechanical rupture, leading to marked reductions in cell volume due to cytosolic leakage. On nanotopographies with densities of 8 per ÎŒm(2) and tip diameters greater than 100Â nm, bacteria predominantly adhered between nanostructures, resulting in cell impedance
tDCSâInduced Analgesia and Electrical Fields in PainâRelated Neural Networks in Chronic Migraine
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93711/1/j.1526-4610.2012.02141.x.pd
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