359 research outputs found

    Practische Anweisung zur nĂŒzlichsten Magazin-Bienenzucht vor alle Gegenden : wordurch die Bienen in Strohkörben und hölzernen KĂ€sten, durchs SchwĂ€rmen und Ableger machen, ohne zu fĂŒttern, sicher zu vermehren, von ihnen Honig und Wachs, ohne Tödten und Beschneiden zu erlangen ; wo bey richtiger Behandlung, in einem guten Clima, jeder guter Bienenstock jĂ€hrlich 5 Gulden Nutzen bringt, auch bey recht guten Bienen-Jahren solches verdoppelt, und man ihn Lebenslang benutzen kann ; nebst einer Anweisung zu einer nĂŒzlichen Wald-Bienenzucht, welche vor den Grundherrn und Unterthanen vortheilhaft ist ; durch vieljĂ€hrige Erfahrungen geprĂŒft, und zum gemeinen Nutzen herausgegeben

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    Vollst. Titel: Practische Anweisung zur nĂŒzlichsten Magazin-Bienenzucht vor alle Gegenden : wordurch die Bienen in Strohkörben und hölzernen KĂ€sten, durchs SchwĂ€rmen und Ableger machen, ohne zu fĂŒttern, sicher zu vermehren, von ihnen Honig und Wachs, ohne Tödten und Beschneiden zu erlangen ; wo bey richtiger Behandlung, in einem guten Clima, jeder guter Bienenstock jĂ€hrlich 5 Gulden Nutzen bringt, auch bey recht guten Bienen-Jahren solches verdoppelt, und man ihn Lebenslang benutzen kann ; nebst einer Anweisung zu einer nĂŒzlichen Wald-Bienenzucht, welche vor den Grundherrn und Unterthanen vortheilhaft ist ; durch vieljĂ€hrige Erfahrungen geprĂŒft, und zum gemeinen Nutzen herausgegebe

    Band bending inversion in Bi2_2Se3_3 nanostructures

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    Shubnikov-de-Haas oscillations were studied under high magnetic field in Bi2_2Se3_3 nanostructures grown by Chemical Vapor Transport, for different bulk carrier densities ranging from 3×1019cm−33\times10^{19}\text{cm}^{-3} to 6×1017cm−36\times10^{17}\text{cm}^{-3}. The contribution of topological surface states to electrical transport can be identified and separated from bulk carriers and massive two-dimensional electron gas. Band bending is investigated, and a crossover from upward to downward band bending is found at low bulk density, as a result of a competition between bulk and interface doping. These results highlight the need to control electrical doping both in the bulk and at interfaces in order to study only topological surface states.Comment: 6 pages, 4 figure

    Studying the ephemeral, cultures of digital oblivion Identifying patterns in Instagram Stories

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    In diesem Beitrag stellen wir unsere Work-In-Progress Social-Media-Studie zu Instagram-Stories wÀhrend der Bundestagswahl 2021 vor. Da es wenig Daten zu den Inhalten und Elementen der Stories gibt haben wir ein Annotationstool entwickelt, mit dem durch Crowdsourcing Stories auf privaten Profilen und denen von Influencern annotiert und beschrieben werden können. ZusÀtzlich wurden die Stories politischer Parteien und derer Spitzenkandidat*innen automatisiert gesammelt und teilautomatisiert annotiert. Die beiden Korpora werden im weiteren Verlauf miteinander verglichen um zunÀchst auf einer Metaebene unterschiede und parallelen der Story-Nutzung zwischen Privatpersonen und politischer Akteure sowie Influencern zu erfassen. Als Nebeneffekt erhalten wir ein Korpus das es entgegen der vorhandenen Literatur zum ersten Mal erlaubt quantitative Aussagen zu Instagram-Stories machen kann: Welche Elemente und Medien werden genutzt, welche Inhalte geteilt

    Basis set convergence in extended systems: infinite hydrogen fluoride and hydrogen chloride chains

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    Basis set convergence of the Hartree-Fock and the correlation energy is examined for the hydrogen bonded infinite bent chains (HF)_infinity and (HCl)_infinity. We employ series of correlation consistent basis sets up to quintuple zeta quality together with a coupled cluster method (CCSD) to describe electron correlation on ab initio level. The Hartree-Fock energy converges rapidly with increasing basis set quality whereas the correlation energy is found to be slowly convergent for the same series of basis sets. We study basis set extrapolation for (HF)_infinity and (HCl)_infinity and show that it substantially enhances the accuracy of both the Hartree-Fock and the correlation energy in extended systems.Comment: 12 pages, 4 figures, 4 tables, LaTeX, corrected typo

    Cellular uptake and in vitro antitumor efficacy of composite liposomes for neutron capture therapy

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    BACKGROUND Neutron capture therapy for glioblastoma has focused mainly on the use of 10B as neutron capture isotope. However, 157Gd offers several advantages over boron, such as higher cross section for thermal neutrons and the possibility to perform magnetic resonance imaging during neutron irradiation, thereby combining therapy and diagnostics. We have developed different liposomal formulations of gadolinium-DTPA (MagnevistÂź) for application in neutron capture therapy of glioblastoma. The formulations were characterized physicochemically and tested in vitro in a glioma cell model for their effectiveness. METHODS Liposomes entrapping gadolinium-DTPA as neutron capture agent were manufactured via lipid/film-extrusion method and characterized with regard to size, entrapment efficiency and in vitro release. For neutron irradiation, F98 and LN229 glioma cells were incubated with the newly developed liposomes and subsequently irradiated at the thermal column of the TRIGA reactor in Mainz. The dose rate derived from neutron irradiation with 157Gd as neutron capturing agent was calculated via Monte Carlo simulations and set in relation to the respective cell survival. RESULTS The liposomal Gd-DTPA reduced cell survival of F98 and LN229 cells significantly. Differences in liposomal composition of the formulations led to distinctly different outcome in cell survival. The amount of cellular Gd was not at all times proportional to cell survival, indicating that intracellular deposition of formulated Gd has a major influence on cell survival. The majority of the dose contribution arises from photon cross irradiation compared to a very small Gd-related dose. CONCLUSIONS Liposomal gadolinium formulations represent a promising approach for neutron capture therapy of glioblastoma cells. The liposome composition determines the uptake and the survival of cells following radiation, presumably due to different uptake pathways of liposomes and intracellular deposition of gadolinium-DTPA. Due to the small range of the Auger and conversion electrons produced in 157Gd capture, the proximity of Gd-atoms to cellular DNA is a crucial factor for infliction of lethal damage. Furthermore, Gd-containing liposomes may be used as MRI contrast agents for diagnostic purposes and surveillance of tumor targeting, thus enabling a theranostic approach for tumor therapy

    Generation of Complex Azabicycles and Carbobicycles from Two Simple Compounds in a Single Operation through a Metal‐Free Six‐Step Domino Reaction

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    Aza‐ and carbobicyclic compounds possess favorable pharmaceutical properties, but they are difficult to access. Herein, we demonstrate an unprecedented organocatalytic two component six‐step chemodivergent domino reaction, which provides a straightforward, sustainable and atom economical route to difficult‐to‐access complex bicyclic architectures: azabicycles and carbobicycles, whose ratios can be controlled by the applied electrophiles and catalysts. Detailed NMR and X‐ray studies on the structures and relative stereochemistry of selected compounds are presented. Mechanistic investigations of the chemoselective branching step have been carried out with DFT methods in conjunction with semiempirical van der Waals interactions. This new domino reaction opens up a new vista of generating, in a single operation, new bioactive compounds with strong antiviral properties (EC50 up to 0.071 Όm for human cytomegalovirus (HCMV)) outperforming clinically used ganciclovir (EC50 2.6 Όm).Six steps in one go! An unprecedented two component six‐step domino reaction, providing a straightforward and atom economical route to bioactive azabicycles and carbobicycles is presented. DFT calculations accounting for dispersion interactions revealed that chemoselectivity might result from small differences in transition state and reaction energies of the branching step. This reaction opens up a new vista of generating, in a single operation, new antivirals outperforming clinically used drugs.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137557/1/chem201504798.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137557/2/chem201504798_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137557/3/chem201504798-sup-0001-misc_information.pd

    Blood Pressure in Seizures and Epilepsy

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    In this narrative review, we summarize the current knowledge of neurally mediated blood pressure (BP) control and discuss how recently described epilepsy- and seizure-related BP alterations may contribute to premature mortality and sudden unexpected death in epilepsy (SUDEP). Although people with epilepsy display disturbed interictal autonomic function with a shift toward predominant sympathetic activity, prevalence of arterial hypertension is similar in people with and without epilepsy. BP is transiently increased in association with most types of epileptic seizures but may also decrease in some, illustrating that seizure activity can cause both a decrease and increase of BP, probably because of stimulation or inhibition of distinct central autonomic function by epileptic activity that propagates into different neuronal networks of the central autonomic nervous system. The principal regulatory neural loop for short-term BP control is termed baroreflex, mainly involving peripheral sensors and brain stem nuclei. The baroreflex sensitivity (BRS, expressed as change of interbeat interval per change in BP) is intact after focal seizures, whereas BRS is markedly impaired in the early postictal period following generalized convulsive seizures (GCS), possibly due to metabolically mediated muscular hyperemia in skeletal muscles, a massive release of catecholamines and compromised brain stem function. Whilst most SUDEP cases are probably caused by a cardiorespiratory failure during the early postictal period following GCS, a profoundly disturbed BRS may allow a life-threatening drop of systemic BP in the aftermath of GCS, as recently reported in a patient as a plausible cause of SUDEP in a few patients

    Early and Differential Diagnosis of Dementia and Mild Cognitive Impairment Design and Cohort Baseline Characteristics of the German Dementia Competence Network

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    Background: The German Dementia Competence Network (DCN) has established procedures for standardized multicenter acquisition of clinical, biological and imaging data, for centralized data management, and for the evaluation of new treatments. Methods: A longitudinal cohort study was set up for patients with mild cognitive impairment (MCI), patients with mild dementia and control subjects. The aims were to establish the diagnostic, differential diagnostic and prognostic power of a range of clinical, laboratory and imaging methods. Furthermore, 2 clinical trials were conducted with patients suffering from MCI and mild to moderate Alzheimer's Disease (AD). These trials aimed at evaluating the efficacy and safety of the combination of galantamine and memantine versus galantamine alone. Results: Here, we report on the scope and projects of the DCN, the methods that were employed, the composition and flow within the diverse groups of patients and control persons and on the clinical and neuropsychological baseline characteristics of the group of 2,113 subjects who participated in the observational and clinical trials. Conclusion: These data have an impact on the procedures for the early and differential clinical diagnosis of dementias, the current standard treatment of AD as well as on future clinical trials in AD. Copyright (C) 2009 S. Karger AG, Base

    A Student-t based filter for robust signal detection

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    The search for gravitational-wave signals in detector data is often hampered by the fact that many data analysis methods are based on the theory of stationary Gaussian noise, while actual measurement data frequently exhibit clear departures from these assumptions. Deriving methods from models more closely reflecting the data's properties promises to yield more sensitive procedures. The commonly used matched filter is such a detection method that may be derived via a Gaussian model. In this paper we propose a generalized matched-filtering technique based on a Student-t distribution that is able to account for heavier-tailed noise and is robust against outliers in the data. On the technical side, it generalizes the matched filter's least-squares method to an iterative, or adaptive, variation. In a simplified Monte Carlo study we show that when applied to simulated signals buried in actual interferometer noise it leads to a higher detection rate than the usual ("Gaussian") matched filter.Comment: 17 pages, 6 figure
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