1,195 research outputs found

    Annealing tests of in-pile irradiated oxide coated U–Mo/Al–Si dispersed nuclear fuel

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    Authors do acknowledge the MERARG team for their experimental work (CEA) and F. Charollais, J. Noirot and finally B. Kapusta for their advices and comments. This study was supported by a combined Grant (FRM0911) of the Bundesministerium für Bildung und Forschung (BMBF) and the Bayerisches Staatsministerium für Wissenschaft, Forschung und Kunst (StMWFK).U–Mo/Al based nuclear fuels have been worldwide considered as a promising high density fuel for the conversion of high flux research reactors from highly enriched uranium to lower enrichment. In this paper, we present the annealing test up to 1800°C of in-pile irradiated U–Mo/Al–Si fuel plate samples. More than 70% of the fission gases (FGs) are released during two major FG release peaks around 500°C and 670°C. Additional characterisations of the samples by XRD, EPMA and SEM suggest that up to 500°C FGs are released from IDL/matrix interfaces. The second peak at 670°C representing the main release of FGs originates from the interaction between U–Mo and matrix in the vicinity of the cladding

    The [4+2]‐Cycloaddition of α‐Nitrosoalkenes with Thiochalcones as a Prototype of Periselective Hetero‐Diels–Alder Reactions—Experimental and Computational Studies

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    The [4+2]‐cycloadditions of α‐nitrosoalkenes with thiochalcones occur with high selectivity at the thioketone moiety of the dienophile providing styryl‐substituted 4H‐1,5,2‐oxathiazines in moderate to good yields. Of the eight conceivable hetero‐Diels–Alder adducts only this isomer was observed, thus a prototype of a highly periselective and regioselective cycloaddition has been identified. Analysis of crude product mixtures revealed that the α‐nitrosoalkene also adds competitively to the thioketone moiety of the thiochalcone dimer affording bis‐heterocyclic [4+2]‐cycloadducts. The experiments are supported by high‐level DFT calculations that were also extended to related hetero‐Diels–Alder reactions of other nitroso compounds and thioketones. These calculations reveal that the title cycloadditions are kinetically controlled processes confirming the role of thioketones as superdienophiles. The computational study was also applied to the experimentally studied thiochalcone dimerization, and showed that the 1,2‐dithiin and 2H‐thiopyran isomers are in equilibrium with the monomer. Again, the DFT calculations indicate kinetic control of this process

    Axonemal Lumen Dominates Cytosolic Protein Diffusion inside the Primary Cilium

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    Transport of membrane and cytosolic proteins in primary cilia is thought to depend on intraflagellar transport (IFT) and diffusion. However, the relative contribution and spatial routes of each transport mechanism are largely unknown. Although challenging to decipher, the details of these routes are essential for our understanding of protein transport in primary cilia, a critically affected process in many genetic diseases. By using a high-speed virtual 3D super-resolution microscopy, we have mapped the 3D spatial locations of transport routes for various cytosolic proteins in the 250-nm-wide shaft of live primary cilia with a spatiotemporal resolution of 2 ms and <16 nm. Our data reveal two spatially distinguishable transport routes for cytosolic proteins: an IFT-dependent path along the axoneme, and a passive-diffusion route in the axonemal lumen that escaped previous studies. While all cytosolic proteins tested primarily utilize the IFT path in the anterograde direction, differences are observed in the retrograde direction where IFT20 only utilizes IFT, and approximately half of KIF17 and one third of α–tubulin utilizes diffusion besides IFT

    Long-term results of a multicenter SAKK trial on high-dose ifosfamide and doxorubicin in advanced or metastatic gynecologic sarcomas

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    Background: Dose intensive chemotherapy has not been tested prospectively for the treatment of gynecologic sarcomas. We investigated the antitumor activity and toxicity of high-dose ifosfamide and doxorubicin, in the context of a multidisciplinary strategy for the treatment of advanced and metastatic, not pretreated, gynecologic sarcomas. Patients and methods: Thirty-nine patients were enrolled onto a phase I-II multicenter trial of ifosfamide, 10 g/m2 as a continuous infusion over 5 days, plus doxorubicin intravenously, 25 mg/m2/day for 3 days with Mesna and granulocyte-colony-stimulating factor every 21 days. Salvage therapy was allowed after chemotherapy. Results: Among the 37 evaluable patients, the tumor was locally advanced (n = 11), with concomitant distant metastases (n = 5) or with distant metastases only (n = 21). After a median of three (range 1-7) chemotherapy cycles, six patients experienced a complete response and 12 a partial response for an overall response rate of 49% (95% CI 32% to 66%). The response rate was higher in poorly differentiated tumors (62%) compared with moderately well differentiated ones (18%), but was not different according to histology subtypes. Eleven patients had salvage therapy, either immediately following chemotherapy (n = 7) or at time of progression (n = 4). With a median follow-up time of 5 years, the median overall survival was 30.5 months. Hematological toxicity was as expected neutropenia, thrombopenia and anemia ≥grade 3 at 50%, 34% and 33% of cycles respectively. No toxic death occurred. Conclusions: High-dose ifosfamide plus doxorubicin is an active regimen for all subtypes of gynecological sarcomas. Its toxicity was manageable in a multicentric setting. The prolonged survival might be due to the multidisciplinary strategy that was possible in one-third of the patient

    Organelle-specific targeting of polymersomes into the cell nucleus

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    Synthetic nanomaterials are being sought to shuttle therapeutic payloads directly into the cell nucleus as a major target for chemo- and gene-based therapies. However, it remains uncertain whether and how synthetic entities are able to bypass the nuclear pore complexes (NPCs) that regulate transport into and out of the nucleus. We have constructed biocompatible polymer vesicles that infiltrate NPCs and resolved their nuclear uptake mechanism in vitro and in vivo. Their ability to deliver payloads directly into cell nuclei is further validated by transmission electron microscopy.Organelle-specific nanocarriers (NCs) are highly sought after for delivering therapeutic agents into the cell nucleus. This necessitates nucleocytoplasmic transport (NCT) to bypass nuclear pore complexes (NPCs). However, little is known as to how comparably large NCs infiltrate this vital intracellular barrier to enter the nuclear interior. Here, we developed nuclear localization signal (NLS)-conjugated polymersome nanocarriers (NLS-NCs) and studied the NCT mechanism underlying their selective nuclear uptake. Detailed chemical, biophysical, and cellular analyses show that karyopherin receptors are required to authenticate, bind, and escort NLS-NCs through NPCs while Ran guanosine triphosphate (RanGTP) promotes their release from NPCs into the nuclear interior. Ultrastructural analysis by regressive staining transmission electron microscopy further resolves the NLS-NCs on transit in NPCs and inside the nucleus. By elucidating their ability to utilize NCT, these findings demonstrate the efficacy of polymersomes to deliver encapsulated payloads directly into cell nuclei

    Ecological Guild Evolution and the Discovery of the World's Smallest Vertebrate

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    Living vertebrates vary drastically in body size, yet few taxa reach the extremely minute size of some frogs and teleost fish. Here we describe two new species of diminutive terrestrial frogs from the megadiverse hotspot island of New Guinea, one of which represents the smallest known vertebrate species, attaining an average body size of only 7.7 mm. Both new species are members of the recently described genus Paedophryne, the four species of which are all among the ten smallest known frog species, making Paedophryne the most diminutive genus of anurans. This discovery highlights intriguing ecological similarities among the numerous independent origins of diminutive anurans, suggesting that minute frogs are not mere oddities, but represent a previously unrecognized ecological guild

    Correlation between Macular Neovascularization (MNV) Type and Druse Type in Neovascular Age-Related Macular Degeneration (AMD) Based on the CONAN Classification

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    To investigate associations and predictive factors between macular neovascularization (MNV) lesion variants and drusen types in patients with treatment-naĂŻve neovascular age-related macular degeneration (AMD). Methods: Multimodal imaging was retrospectively reviewed for druse type (soft drusen, subretinal drusenoid deposits (SDDs) or mixed) and MNV type (MNV 1, MNV 2, MNV 1/2 or MNV 3). The Consensus on Neovascular AMD Nomenclature (CONAN) classification was used for characterizing MNV at baseline. Results: One eye of each eligible patient was included (n = 191). Patients with predominant SDDs had an increased adjusted odds ratio (aOR) for MNV 2 (23.4453, p = 0.0025) and any type of MNV 3 (8.7374, p < 0.0001). Patients with MNV 1/2 had an aOR for predominant SDDs (0.3284, p = 0.0084). Patients with MNV1 showed an aOR for SDDs (0.0357, p < 0.0001). Eyes with SDDs only without other drusen types showed an aOR for MNV 2 (9.2945, p < 0.0001). Conclusions: SDDs represent a common phenotypic characteristic in AMD eyes with treatment-naĂŻve MNV. The aOR for eyes with predominant SDDs to develop MNV 2 and MNV 3 was much higher, possibly due to their location in the subretinal space. The predominant druse type may help to predict which type of MNV will develop during the course of AMD

    Genetic inhibition of neurotransmission reveals role of glutamatergic input to dopamine neurons in high-effort behavior

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    Midbrain dopamine neurons are crucial for many behavioral and cognitive functions. As the major excitatory input, glutamatergic afferents are important for control of the activity and plasticity of dopamine neurons. However, the role of glutamatergic input as a whole onto dopamine neurons remains unclear. Here we developed a mouse line in which glutamatergic inputs onto dopamine neurons are specifically impaired, and utilized this genetic model to directly test the role of glutamatergic inputs in dopamine-related functions. We found that while motor coordination and reward learning were largely unchanged, these animals showed prominent deficits in effort-related behavioral tasks. These results provide genetic evidence that glutamatergic transmission onto dopaminergic neurons underlies incentive motivation, a willingness to exert high levels of effort to obtain reinforcers, and have important implications for understanding the normal function of the midbrain dopamine system.Fil: Hutchison, M. A.. National Institutes of Health; Estados UnidosFil: Gu, X.. National Institutes of Health; Estados UnidosFil: Adrover, MartĂ­n Federico. National Institutes of Health; Estados Unidos. Consejo Nacional de Investigaciones CientĂ­ficas y TĂŠcnicas. Instituto de Investigaciones en IngenierĂ­a GenĂŠtica y BiologĂ­a Molecular "Dr. HĂŠctor N. Torres"; ArgentinaFil: Lee, M. R.. National Institutes of Health; Estados UnidosFil: Hnasko, T. S.. University of California at San Diego; Estados UnidosFil: Alvarez, V. A.. National Institutes of Health; Estados UnidosFil: Lu, W.. National Institutes of Health; Estados Unido

    A strategy to characterize the LISA-Pathfinder cold gas thruster system

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    The cold gas micro-propulsion system that will be used during the LISA-Pathfinder mission will be one of the most important component used to ensure the "free-fall" of the enclosed test masses. In this paper we present a possible strategy to characterize the effective direction and amplitude gain of each of the 6 thrusters of this system

    Analysis of Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) Parameters in Young Adults after SARS-CoV-2 Infection (COVID-19) Compared with Healthy Young Controls

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    Purpose: To compare retinal changes in young adults with previous SARS-CoV-2 infection with healthy young controls using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Methods: This prospective single-center study was conducted at the University Hospital of Zurich, Zurich, Switzerland. Participants were imaged from May to November 2021 using the SOLIX device (Visionix International SAS, Pont-de-l’Arche, France). We performed 12 mm × 12 mm, 6.4 mm × 6.4 mm, 6 mm × 6 mm and 3 mm × 3 mm OCT and OCTA scans, as well as fundus photography of each participant’s eyes. Results: In total, 466 participants were imaged. Of these, 233 were healthy controls with negative RT-PCR tests for SARS-CoV-2, 168 were young adults who had a SARS-CoV-2 infection at least 180 days previously, 19 were participants who had a SARS-CoV-2 infection < 180 days previously, and 46 were participants with asymptomatic SARS-CoV-2 infection (i.e., serologically positive but with no symptoms). Compared with healthy controls, statistically significant differences were found for OCTA recordings of the optic disc for the whole image (WI) and WI capillary vessel density, with both being higher in the SARS-CoV-2 group. Conclusion: Statistically significant results were only observed for selected variables, and in parts, only unilaterally, with relatively large p values (p = 0.02–0.03). Thus, we did not interpret these as clinically significant, leading to the conclusion that young and otherwise healthy individuals (mainly men) seem to recover from mild COVID-19 infections with no ophthalmological residues
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