192 research outputs found

    Thiol-gelatin-norbornene bioink for laser‐based high‐definition bioprinting

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    Two-photon polymerization (2PP) is a lithography-based 3D printing method allowing the fabrication of 3D structures with sub-micrometer resolution. This work focuses on the characterization of gelatin-norbornene (Gel-NB) bioinks which enables the embedding of cells via 2PP. The high reactivity of the thiol-ene system allows 2PP processing of cell-containing materials at remarkably high scanning speeds (1000 mm s(-1)) placing this technology in the domain of bioprinting. Atomic force microscopy results demonstrate that the indentation moduli of the produced hydrogel constructs can be adjusted in the 0.2-0.7 kPa range by controlling the 2PP processing parameters. Using this approach gradient 3D constructs are produced and the morphology of the embedded cells is observed in the course of 3 weeks. Furthermore, it is possible to tune the enzymatic degradation of the crosslinked bioink by varying the applied laser power. The 3D printed Gel-NB hydrogel constructs show exceptional biocompatibility, supported cell adhesion, and migration. Furthermore, cells maintain their proliferation capacity demonstrated by Ki-67 immunostaining. Moreover, the results demonstrate that direct embedding of cells provides uniform distribution and high cell loading independently of the pore size of the scaffold. The investigated photosensitive bioink enables high-definition bioprinting of well-defined constructs for long-term cell culture studies

    Terahertz radiation detection with a cantilever-based photoacoustic sensor

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    We report the photoacoustic (PA) response in the terahertz (THz) range by employing a detection process actuated with a silicon cantilever pressure sensor and a carbon-based radiation absorber. The detection relies on the mechanical response of the cantilever, when the volume of the carrier gas inside the PA cell expands with the heat produced by the radiation absorber. The detector interferometrically monitors the movement of the cantilever sensor to generate the PA signal. We selected the absorber material with the highest THz responsivity for detailed studies at 1.4 THz (214 pm wavelength). The observed responsivities of two different radiation absorbers are nearly the same at 1.4 THz and agree within 10% with responsivity values at 0.633 pm wavelength. The results demonstrate the potential of covering with a single PA detector a broad spectral range with approximately constant responsivity, large dynamic range, and high damage threshold. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License.Peer reviewe

    Utilisation de la photogrammĂ©trie pour l’étude de la vĂ©gĂ©tation riveraine

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    International audienceThis study presents the results of methodological tests in aerial photogrammetry with the objective of a diachronic survey of riparian vegetation in three dimensions, i.e. its spatial distribution and height. The study is undertaken at two complementary scales. The first one corresponds to a 10 km reach of the Allier river floodplain. At this scale, aerial photographs were taken from a small airplane. The second level of analysis corresponds to a wooded point bar located within the 10 km reach. At this scale, the photographs were taken from an unmanned aerial vehicle (UAV). Canopy height models (CHM) are produced at two scales of analysis. The accuracy of the CHMs is then analysed by comparison with vegetation height measurements collected during a filed campaign. The results show significant agreement for the models derived from two approaches, with an error of one meter at the floodplain scale and few centimetres at the bar scale. This variation in error is mainly due to different photographic resolutions. The two approaches appeared to be complementary. The first one is adequate for mapping vegetation structure at the floodplain scale, the second for mapping vegetation in smaller areas but at a higher resolution.Cette Ă©tude prĂ©sente les rĂ©sultats de tests mĂ©thodologiques rĂ©alisĂ©s en photogrammĂ©trie aĂ©rienne avec pour objectif le suivi diachronique de la vĂ©gĂ©tation riveraine dans ses trois dimensions, c’est-Ă -dire sa distribution spatiale et sa hauteur. L’étude est menĂ©e Ă  deux Ă©chelles d’analyse. La premiĂšre Ă©chelle est celle d’un tronçon longitudinal de 10 km de la plaine alluviale de la riviĂšre Allier. À cette Ă©chelle de travail, un avion a Ă©tĂ© utilisĂ© pour les prises de vue aĂ©rienne. La deuxiĂšme Ă©chelle d’analyse est celle d’un banc boisĂ©, localisĂ© dans la zone de 10 km. À cette Ă©chelle, la couverture photographique a Ă©tĂ© faite Ă  l’aide d’un drone. Pour les deux objets d’étude des modĂšles de hauteur du couvert vĂ©gĂ©tal (MHC) sont produits. La prĂ©cision des MHC est ensuite vĂ©rifiĂ©e Ă  partir de la mesure de la hauteur d’arbres sur le terrain. Les rĂ©sultats rĂ©vĂšlent une trĂšs bonne prĂ©cision des modĂšles pour les deux approches, de l’ordre du mĂštre Ă  l’échelle du tronçon de 10 km et de quelques centimĂštres Ă  l’échelle du banc. Cette inĂ©galitĂ© s’explique surtout par des rĂ©solutions photographiques diffĂ©rentes pour les deux missions. Il ressort de ce travail que les deux approches sont complĂ©mentaires. La premiĂšre permet de cartographier la structure de la vĂ©gĂ©tation Ă  l’échelle de la plaine alluviale, la deuxiĂšme permet une cartographie de la vĂ©gĂ©tation Ă  plus haute rĂ©solution mais seulement Ă  une Ă©chelle plus rĂ©duite

    Comparison of high-resolution electric field measurements in a hollow cathode glow-discharge operated in hydrogen and deuterium

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    High-resolution measurements of the electric field strength in a hollow cathode discharge operated with deuterium gas are presented. The electric field strength is determined via Stark effect splitting of the 2S level of deuterium atoms using Doppler-free two-photon laser spectroscopy. The results are compared with equivalent measurements when the discharge was operated in hydrogen. The measured electric fields are analyzed using two classical models to obtain valuable parameters about the discharge dynamics, such as the energy of the ions and their mean free path in the cathode region. This information is compared with previous results for hydrogen and allows insight into the differences when gas discharges are operated with one of the isotopes

    Acute Renal Failure on Immune Reconstitution in an HIV-Positive Patient with Miliary Tuberculosis

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    Immune reconstitution syndrome following HAART in human immunodeficiency virus (HIV)-infected patients is characterized by inflammatory worsening of organ functions despite improvement in HIV surrogate markers of HIV infection. We describe a patient with miliary tuberculosis and urinary shedding of acid fast bacilli who developed acute renal failure 8 weeks after initiation of antituberculosis therapy and 6 weeks after initiation of HAART. The diagnostic workup and further course of disease implicated immune reconstitution syndrome as the cause of acute renal failur

    Risk of Cutaneous Squamous Cell Carcinoma Development in Renal Transplant Recipients Is Independent of TMC/EVER Alterations

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    Renal transplant recipients (RTRs) have an increased risk of developing nonmelanoma skin cancer, mainly cutaneous squamous cell carcinoma (cSCC). Two genes (TMC6/EVER1 and TMC8/EVER2), mutated in epidermodysplasia verruciformis (EV) patients with an increased risk of cSCC development, contain numerous single-nucleotide polymorphisms (SNPs).; To evaluate the effect of SNPs in both TMC/EVER genes on the different susceptibilities of RTRs to cSCC.; We determined the occurrence of cSCC in 105 RTRs who were transplanted at least 7 years previously and investigated the frequency of 26 SNPs within both TMC/EVER genes in severely affected (n = 16) as well as in nonaffected RTRs (n = 25).; Our data did not indicate a significant association between any SNP genotype and risk of cSCC development in RTRs.; To clarify the correlation between SNPs in both TMC genes and cSCC development in RTRs, integrated investigations of large cohorts including both RTRs and immunocompetent individuals with consideration of cSCC status, SNP genotype and human papillomavirus status might be necessary

    Risk of Cutaneous Squamous Cell Carcinoma Development in Renal Transplant Recipients Is Independent of TMC/EVER Alterations

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    Renal transplant recipients (RTRs) have an increased risk of developing nonmelanoma skin cancer, mainly cutaneous squamous cell carcinoma (cSCC). Two genes (TMC6/EVER1 and TMC8/EVER2), mutated in epidermodysplasia verruciformis (EV) patients with an increased risk of cSCC development, contain numerous single-nucleotide polymorphisms (SNPs).; To evaluate the effect of SNPs in both TMC/EVER genes on the different susceptibilities of RTRs to cSCC.; We determined the occurrence of cSCC in 105 RTRs who were transplanted at least 7 years previously and investigated the frequency of 26 SNPs within both TMC/EVER genes in severely affected (n = 16) as well as in nonaffected RTRs (n = 25).; Our data did not indicate a significant association between any SNP genotype and risk of cSCC development in RTRs.; To clarify the correlation between SNPs in both TMC genes and cSCC development in RTRs, integrated investigations of large cohorts including both RTRs and immunocompetent individuals with consideration of cSCC status, SNP genotype and human papillomavirus status might be necessary

    Defining activities in neurovascular microsurgery training : entrustable professional activities for vascular neurosurgery

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    Background Entrustable professional activities (EPAs) represent an assessment framework with an increased focus on competency-based assessment. Originally developed and adopted for undergraduate medical education, concerns over resident ability to practice effectively after graduation have led to its implementation in residency training but yet not in vascular neurosurgery. Subjective assessment of resident or fellow performance can be problematic, and thus, we aim to define core EPAs for neurosurgical vascular training. Methods We used a nominal group technique in a multistep interaction between a team of experienced neurovascular specialists and a medical educator to identify relevant EPAs. Panel members provided feedback on the EPAs until they reached consent. Results The process produced seven core procedural EPAs for vascular residency and fellowship training, non-complex aneurysm surgery, complex aneurysm surgery, bypass surgery, arteriovenous malformation resection, spinal dural fistula surgery, perioperative management, and clinical decision-making. Conclusion These seven EPAs for vascular neurosurgical training may support and guide the neurosurgical society in the development and implementation of EPAs as an evaluation tool and incorporate entrustment decisions in their training programs.Peer reviewe

    Zusammenarbeit ĂŒber die Grenzen hinweg

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    Netzwerk fĂŒr wissenschaftliche Weiterbildung und Personalentwicklung der UniversitĂ€ten in Österreich: AUCEN (Elke Gornik/Monika Kil/Katharina Mallich-Pötz/Anna Steiger/Christine Stöckler-Penz) In diesem Beitrag werden die Entstehung von AUCEN, die Rahmenbedingungen der UniversitĂ€tsgesetzgebung fĂŒr wissenschaftliche Weiterbildung und Personalentwicklung, ProjektaktivitĂ€ten und aktuelle Herausforderungen ausgefĂŒhrt. Wirkungsvolle Interessenvertretung der universitĂ€ren Weiterbildung in der Schweiz: Swissuni (Andreas Fischer). Working together to promote University Lifelong learning in Europe: eucen (Françoise de Viron). This chapter presents eucen, a specific European university lifelong learning network. Using an organisational framework, based on the concepts of collaborative inter-organisational network and community of practice, it describes the characteristics, the functions and benefits of this network and highlights some prerequisites for its development. It concludes by a short test application of the framework to other networks dedicated to LLL at national level and highlights some examples in the case of Germany and the DGWF network
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