267 research outputs found

    Vinylene-Linked Covalent Organic Frameworks by Base-Catalyzed Aldol Condensation

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    Two 2D covalent organic frameworks (COFs) linked by vinylene (−CH=CH−) groups (V‐COF‐1 and V‐COF‐2) are synthesized by exploiting the electron deficient nature of the aromatic s‐triazine unit of C3‐symmetric 2,4,6‐trimethyl‐s‐triazine (TMT). The acidic terminal methyl hydrogens of TMT can easily be abstracted by a base, resulting in a stabilized carbanion, which further undergoes aldol condensation with multitopic aryl aldehydes to be reticulated into extended crystalline frameworks (V‐COFs). Both V‐COF‐1 (with terepthalaldehyde (TA)) and V‐COF‐2 (with 1,3,5‐tris(p‐formylphenyl)benzene (TFPB)) are polycrystalline and exhibit permanent porosity and BET surface areas of 1341 m2 g−1 and 627 m2 g−1, respectively. Owing to the close proximity (3.52 Å) of the pre‐organized vinylene linkages within adjacent 2D layers stacked in eclipsed fashion, [2+2] photo‐cycloadditon in V‐COF‐1 formed covalent crosslinks between the COF layers.TU Berlin, Open-Access-Mittel - 2019DFG, 390540038, EXC 2008: UniSysCa

    Unravelling the mechanism of non-ribosomal peptide synthesis by cyclodipeptide synthases.

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    International audienceCyclodipeptide synthases form cyclodipeptides from two aminoacyl transfer RNAs. They use a ping-pong mechanism that begins with transfer of the aminoacyl moiety of the first aminoacyl tRNA onto a conserved serine, yielding an aminoacyl enzyme. Combining X-ray crystallography, site-directed mutagenesis and affinity labelling of the cyclodipeptide synthase AlbC, we demonstrate that the covalent intermediate reacts with the aminoacyl moiety of the second aminoacyl tRNA, forming a dipeptidyl enzyme, and identify the aminoacyl-binding sites of the aminoacyl tRNAs

    CRH – Groupe d’anthropologie historique de l’occident mĂ©diĂ©val (GAHOM)

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    JĂ©rĂŽme Baschet, maĂźtre de confĂ©rencesJean-Claude Bonne, Jean-Claude Schmitt, directeurs d’étudesMichel Pastoureau, directeur d’études supplĂ©antAline Debert, ingĂ©nieur d’études au CNRS Groupe de travail sur les images mĂ©diĂ©vales L’analyse et l’informatisation d’un fonds de miniatures, menĂ©es avec les Ă©tudiants, a progressĂ© grĂące Ă  l’indexation des enluminures de deux manuscrits exceptionnels, les Rothschild Canticles et le Ci nous dit. Les Rothschild Canticles (Yale University, Beinecke Rare B..

    CRH – Groupe d’anthropologie historique de l’occident mĂ©diĂ©val (GAHOM)

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    JĂ©rĂŽme Baschet, maĂźtre de confĂ©rencesJean-Claude Bonne, Jean-Claude Schmitt, directeurs d’étudesMichel Pastoureau, directeur d’études supplĂ©antAline Debert, ingĂ©nieur d’études au CNRS Groupe de travail sur les images mĂ©diĂ©vales L’analyse et l’informatisation d’un fonds de miniatures, menĂ©es avec les Ă©tudiants, a progressĂ© grĂące Ă  l’indexation des enluminures de deux manuscrits exceptionnels, les Rothschild Canticles et le Ci nous dit. Les Rothschild Canticles (Yale University, Beinecke Rare B..

    Social networks and citizen election forecasting: the more friends the better

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    Most citizens correctly forecast which party will win a given election, and such forecasts usually have a higher level of accuracy than voter intention polls. How do citizens do it? We argue that social networks are a big part of the answer: much of what we know as citizens comes from our interactions with others. Previous research has considered only indirect characteristics of social networks when analyzing why citizens are good forecasters. We use a unique German survey and consider direct measures of social networks in order to explore their role in election forecasting. We find that three network characteristics – size, political composition, and frequency of political discussion – are among the most important variables when predicting the accuracy of citizens’ election forecasts

    Whole Transcriptome Profiling of Successful Immune Response to Vibrio Infections in the Oyster Crassostrea gigas by Digital Gene Expression Analysis

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    The cultivated Pacific oyster Crassostrea gigas has suffered for decades large scale summer mortality phenomenon resulting from the interaction between the environment parameters, the oyster physiological and/or genetic status and the presence of pathogenic microorganisms including Vibrio species. To obtain a general picture of the molecular mechanisms implicated in C. gigas immune responsiveness to circumvent Vibrio infections, we have developed the first deep sequencing study of the transcriptome of hemocytes, the immunocompetent cells. Using Digital Gene Expression (DGE), we generated a transcript catalog of up-regulated genes from oysters surviving infection with virulent Vibrio strains (Vibrio splendidus LGP32 and V. aestuarianus LPi 02/41) compared to an avirulent one, V. tasmaniensis LMG 20012T. For that an original experimental infection protocol was developed in which only animals that were able to survive infections were considered for the DGE approach. We report the identification of cellular and immune functions that characterize the oyster capability to survive pathogenic Vibrio infections. Functional annotations highlight genes related to signal transduction of immune response, cell adhesion and communication as well as cellular processes and defence mechanisms of phagocytosis, actin cytosqueleton reorganization, cell trafficking and autophagy, but also antioxidant and anti-apoptotic reactions. In addition, quantitative PCR analysis reveals the first identification of pathogen-specific signatures in oyster gene regulation, which opens the way for in depth molecular studies of oyster-pathogen interaction and pathogenesis. This work is a prerequisite for the identification of those physiological traits controlling oyster capacity to survive a Vibrio infection and, subsequently, for a better understanding of the phenomenon of summer mortality

    The Beaker phenomenon and the genomic transformation of northwest Europe

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    From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries

    The global abundance of tree palms

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    Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≄10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Real-world study of the efficacy and safety of belantamab mafodotin (GSK2857916) in relapsed or refractory multiple myeloma based on data from the nominative ATU in France: the IFM 2020-04 study

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    Belantamab mafodotin (BM) is an anti-BCMA antibody-drug conjugate (GSK2857916) that represents an alternative option in multiple myeloma. We sought to assess the efficacy and safety of BM in a real-world setting in patients who benefited from an early access program. We conducted an observational, retrospective, multicenter study. Eligibility criteria were treatment of relapsed or refractory multiple myeloma (RRMM) in monotherapy in adult patients who have received at least three lines of therapy previously, including at least one immunomodulatory agent (IMiD), a proteasome inhibitor (PI) and an anti-CD38 monoclonal antibody, and whose disease progressed during the last treatment period. The primary endpoint of the study is to assess the overall survival (OS). Between November 2019 and December 2020, 106 patients were treated with BM; 97 were eligible for the efficacy evaluation and 104 for safety. The median age was 66 (range, 37–82) years. High-risk cytogenetics were identified in 40.9% of patients. Fifty-five (56.7%) patients were triple-class refractory and 11 (11.3%) were penta-class refractory. The median number of prior lines of treatment was five (range, 3–12). The median number of BM cycles administered was three (range, 1–22). The overall response rate at best response was 38.1% (37/97). The median OS was 9.3 months (95% confidence interval [CI]: 5.9-15.3), and median progression-free survival was 3.5 months (95% CI: 1.9-4.7). The median duration of response was 9 months (range, 4.65-10.4). Treatment was delayed for 55 (52.9%) patients including 36.5% for treatment-related toxicity. Ophthalmic adverse events, mainly grade ≀2, were the most common toxicity (48%). The occurrence of keratopathy was 37.5%. Overall, our data are concordant with the results from DREAMM-2 in terms of efficacy and safety on a non-biased population
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