1,288 research outputs found

    On the role of twisted statistics in the noncommutative degenerate electron gas

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    We consider the problem of a degenerate electron gas in the background of a uniformly distributed positive charge, ensuring overall neutrality of the system, in the presence of non-commutativity. In contrast to previous calculations that did not include twisted statistics, we find corrections to the ground state energy already at first order in perturbation theory when the twisted statistics is taken into account. These corrections arise since the interaction energy is sensitive to two particle correlations, which are modified for twisted anti-commutation relations

    Side-effects of cidofovir in the treatment of recurrent respiratory papillomatosis

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    Recurrent respiratory papillomatosis (RRP) is a chronic and difficult to treat disease of the larynx. In 1998, the first article was published that described the use of the antiviral substance cidofovir to treat this disease. Although the results are promising, there remains some concern about the potential carcinogenicity of cidofovir. There is a demand for a qualitative review of the side-effects of this medicine. In this review, the side-effects of cidofovir are investigated. Special attention was given to the potential carcinogenicity of cidofovir. For this review a search is performed in PubMed and EMBASE for relevant articles in which the use of intralesional cidofovir for patients with RRP is described. Eventually, 31 articles could be included for this review. In these articles a total of 188 patients with RRP were described who underwent therapy with intralesional cidofovir. Five of these patients have developed dysplasia of the larynx during the treatment with cidofovir. This is a percentage of 2.7. This percentage is concurrent with the incidence of spontaneous malignant degeneration of RRP (2–3%). Based on this review, it can be concluded that the use of intralesional cidofovir does not increase the risk of laryngeal dysplasia. Apart from the articles that describe the intralesional administration of cidofovir, some articles have been published in which the use of intravenous cidofovir is described as a therapy for RRP. Therefore, a summary is given on the side-effects of intralesional cidofovir as well as a summary on the reported side-effects of the intravenous administration of cidofovir. Based on the outcomes of this review, recommendations are given for a safe use of cidofovir for treatment of recurrent respiratory papillomatosis in the future

    Rational Strain Engineering in Delafossite Oxides for Highly Efficient Hydrogen Evolution Catalysis in Acidic Media

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    The rational design of hydrogen evolution reaction (HER) electrocatalysts which are competitive with platinum is an outstanding challenge to make power-to-gas technologies economically viable. Here, we introduce the delafossites PdCrO2_2, PdCoO2_2 and PtCoO2_2 as a new family of electrocatalysts for the HER in acidic media. We show that in PdCoO2_2 the inherently strained Pd metal sublattice acts as a pseudomorphic template for the growth of a strained (by +2.3%) Pd rich capping layer under reductive conditions. The surface modification continuously improves the electrocatalytic activity by simultaneously increasing the exchange current density j0_0 from 2 to 5 mA/cmgeo2^2_{geo} and by reducing the Tafel slope down to 38 mV/decade, leading to overpotentials η10\eta_{10} < 15 mV for 10 mA/cmgeo2^2_{geo}, superior to bulk platinum. The greatly improved activity is attributed to the in-situ stabilization of a β\beta-palladium hydride phase with drastically enhanced surface catalytic properties with respect to pure or nanostructured palladium. These findings illustrate how operando induced electrodissolution can be used as a top-down design concept for rational surface and property engineering through the strain-stabilized formation of catalytically active phases

    Uncertainty quantification for sparse Fourier recovery

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    One of the most prominent methods for uncertainty quantification in high-dimen-sional statistics is the desparsified LASSO that relies on unconstrained 1\ell_1-minimization. The majority of initial works focused on real (sub-)Gaussian designs. However, in many applications, such as magnetic resonance imaging (MRI), the measurement process possesses a certain structure due to the nature of the problem. The measurement operator in MRI can be described by a subsampled Fourier matrix. The purpose of this work is to extend the uncertainty quantification process using the desparsified LASSO to design matrices originating from a bounded orthonormal system, which naturally generalizes the subsampled Fourier case and also allows for the treatment of the case where the sparsity basis is not the standard basis. In particular we construct honest confidence intervals for every pixel of an MR image that is sparse in the standard basis provided the number of measurements satisfies nmax{slog2slogp,slog2p}n \gtrsim\max\{ s\log^2 s\log p, s \log^2 p \} or that is sparse with respect to the Haar Wavelet basis provided a slightly larger number of measurements

    Bildanalytische Farberkennung zur Geschwindigkeitsregulierung beim Jäteflieger im ökologischen Möhrenanbau

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    Weed control in organic carrot production is time and cost intensive. There are several practicable techniques available for inter-row weed control, but the most sensitive area - ted by manual weeding. Weed regulation is usually done in uniform operations for one field, but weeds appear in a huge spatial variability, reflecting heterogeneous soil and climate conditions. Following the idea of precision farming, we developed a concept for camera-based weed detection, which displays the density as recommendation for velocity adaptation for the driver. The system was tested against the usual weeding with one constant velocity in a field trial with randomized plots. By using the new technology it was possible to increase the area performance by higher average velocities without reducing the weeding quality compared to the usual system. The next step of this low-cost component approach would be a complete implementation into the tractor system with the possibility of automatically velocity regulations

    Sensitivity and specificity of detection methods for erythropoietin doping in cyclists

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    Recombinant human erythropoietin (rHuEPO) is used as doping a substance. Anti-doping efforts include urine and blood testing and monitoring the athlete biological passport (ABP). As data on the performance of these methods are incomplete, this study aimed to evaluate the performance of two common urine assays and the ABP. In a randomized, double-blinded, placebo-controlled trial, 48 trained cyclists received a mean dose of 6000 IU rHuEPO (epoetin beta) or placebo by weekly injection for eight weeks. Seven timed urine and blood samples were collected per subject. Urine samples were analyzed by sarcosyl-PAGE and isoelectric focusing methods in the accredited DoCoLab in Ghent. A selection of samples, including any with false presumptive findings, underwent a second sarcosyl-PAGE confirmation analysis. Hematological parameters were used to construct a module similar to the ABP and analyzed by two evaluators from an Athlete Passport Management Unit. Sensitivity of the sarcosyl-PAGE and isoelectric focusing assays for the detection of erythropoietin abuse were 63.8% and 58.6%, respectively, with a false presumptive finding rate of 4.3% and 6%. None of the false presumptive findings tested positive in the confirmation analysis. Sensitivity was highest between 2 and 6 days after dosing, and dropped rapidly outside this window. Sensitivity of the ABP was 91.3%. Specificity of the urine assays was high; however, the detection window of rHuEPO was narrow, leading to questionable sensitivity. The ABP, integrating longitudinal data, is more sensitive, but there are still subjects that evade detection. Combining these methods might improve performance, but will not resolve all observed shortcomings

    First foods and gut microbes

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    The establishment of the human gut microbiota in early life has been associated with later health and disease. During the 1st months after birth, the microbial composition in the gut is known to be affected by the mode of delivery, use of antibiotics, geographical location and type of feeding (breast/formula). Consequently, the neonatal period and early infancy has attracted much attention. However, after this first period the gut microbial composition continues to develop until the age of 3 years, and these 1st years have been designated “a window of opportunity” for microbial modulation. The beginning and end of this window is currently debated, but it likely coincides with the complementary feeding period, marking the gradual transition from milk-based infant feeding to family diet usually occurring between 6 and 24 months. Furthermore, the ‘first 1000 days,’ i.e., the period from conception until age 2 years, are generally recognized to be of particular importance for the healthy development of children. While dietary changes are known to affect the adult gut microbiota, there is a gap in our knowledge on how the introduction of new dietary components into the diet of infants/young children affects the gut microbiota development. This perspective paper summarizes the currently very few studies addressing the effects of complementary diet on gut microbiota, and highlights the recent finding that transition to family foods greatly impacts the development of gut microbial diversity. Further, we discuss potential impacts on child health and the need for further studies on this important topic

    Radiolabeled albumin through S<sub>N</sub>Ar of cysteines as a potential pretargeting theranostic agent

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    Human serum albumin (HSA) has been shown to be a promising tumor targeting vector and target for generating theranostics by bioconjugation. Unstable chemical conjugation to HSA via a cysteine (Cys34) by reversible Michael additions is most commonly applied for this purpose. Herein, we describe utilization of our recently developed site-selective irreversible S(N)Ar conjugation to Cys34 using perfluorobenzene sulfonyl derivatives to introduce a trans-cyclooctene (TCO) handle. The TCO could then be bioorthogonally ligated within minutes through an inverse-electron demand Diels–Alder reaction (IEDDA) to tetrazines (Tzs) containing a radionuclide. The methodology opens up a wide range of chemistries including pretargeting, ‘click-to-release’ tumor selective drug delivery or ultra-fast and complete conjugation of any drug. The proof-of-principle study demonstrated that the conjugation chemistry is feasible, robust and easy to carry out, being promising for pretargeted imaging and therapy studies as well as selective drug delivery using HSA
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