| 61. |
- Carretero Cerdan, Alba, et al.
(författare)
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One-step microwave-assisted synthesis of amino-functionalized chromium(III) terephthalate MIL-101-NH2
- 2023
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Ingår i: Materials Today Chemistry. - 2468-5194. ; 31
-
Tidskriftsartikel (refereegranskat)abstract
- A single-step microwave (MW)-assisted protocol for the synthesis of MIL-101(Cr) and of MIL-101(Cr)-NH2 is described herein, based on the addition of NaF as the modulator instead of hydrofluoric acid to obtain the corresponding polymers in only 1 h with high crystallinity and yields (>70%, 0.5 g). Compared to classic solvothermal protocols (12-72 h, <30%), MW-assisted synthesis allowed shorter reaction time and improved yields, replacing N,N-dimethylformamide by water. Physicochemical properties of MIL-101(Cr)-NH2 and MIL-101(Cr) obtained through this MW-assisted procedure are more homogenous than those observed for the corresponding solvothermal counterparts, and interestingly, enhanced higher control over nanometric particle size (80-130 vs 400-1000 nm), lower polydispersity, and higher Brunauer-Emett-Teller surface area (2000-2700 vs 1800-2300 m2/g) were observed because of the better accessibility and diffusion of gases throughout the internal pores.& COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 62. |
- Costa, Sergio, 1987, et al.
(författare)
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Development and validation of a finite deformation fibre kinking model for crushing of composites
- 2020
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Ingår i: Composites Science and Technology. - : Elsevier BV. - 0266-3538 .- 1879-1050. ; 197
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Tidskriftsartikel (refereegranskat)abstract
- A mesoscale model for fibre kinking onset and growth in a three-dimensional framework is developed and validated against experimental results obtained in-house as well as from the literature. The model formulation is based on fibre kinking theory i.e. the initially misaligned fibres rotate due to compressive loading and nonlinear shear behaviour. Furthermore, the physically-based response is computed in a novel and efficient way using finite deformation theory. The model validation starts by correlating the numerical results against compression tests of specimens with a known misalignment. The results show good agreement of stiffness and strength for two specimens with low and high misalignment. Fibre kinking growth is validated by simulating the crushing of a flat coupon with the fibres oriented to the load direction. The numerical results show very good agreement with experiments in terms of crash morphology and load response.
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| 63. |
- Costa, Sergio, 1987, et al.
(författare)
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Validation and improvements of a mesoscale finite element constitutive model for fibre kinking growth
- 2019
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Ingår i: ECCM 2018 - 18th European Conference on Composite Materials. - : European Society for Composite Materials. - 9781510896932
-
Konferensbidrag (refereegranskat)abstract
- The present work is focused on the computational challenges and further verification and validation of an advanced fibre kinking model. This model was previously developed by the authors and implemented in a Finite Element (FE) code with a mesh objective formulation. The previous validation in terms of comparison with an analytical and a micromechanical model is herein extended to also encompass FE simulations of longitudinal compression in multiaxial stress states. In addition, numerical improvements have been added to the model targeting its computational efficiency and stability in order to handle multiaxial stress states and large structures.
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| 64. |
- Cremades, Andrés, et al.
(författare)
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Identifying regions of importance in wall-bounded turbulence through explainable deep learning
- 2024
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Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Despite its great scientific and technological importance, wall-bounded turbulence is an unresolved problem in classical physics that requires new perspectives to be tackled. One of the key strategies has been to study interactions among the energy-containing coherent structures in the flow. Such interactions are explored in this study using an explainable deep-learning method. The instantaneous velocity field obtained from a turbulent channel flow simulation is used to predict the velocity field in time through a U-net architecture. Based on the predicted flow, we assess the importance of each structure for this prediction using the game-theoretic algorithm of SHapley Additive exPlanations (SHAP). This work provides results in agreement with previous observations in the literature and extends them by revealing that the most important structures in the flow are not necessarily the ones with the highest contribution to the Reynolds shear stress. We also apply the method to an experimental database, where we can identify structures based on their importance score. This framework has the potential to shed light on numerous fundamental phenomena of wall-bounded turbulence, including novel strategies for flow control.
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| 65. |
- da Silva, Humberto, Jr., et al.
(författare)
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Multiple electron capture, excitation, and fragmentation in C6+-C-60 collisions
- 2014
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 90:3, s. 032701-
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental and theoretical results on single- and multiple-electron capture, and fragmentation, in C6+ + C-60 collisions at velocities in the v(col) = 0.05 - 0.4 a.u. range. We use time-of-flight mass spectrometry and coincidence detection of charged fragments to separate pure target ionization from processes in which the C-60 target is both ionized and fragmented. The coincidence technique allows us to identify different types of fragmentation processes such as C-60(q+) -> C-58(q+) + C-2 and C-60(q+) -> C-58((q-1)+) + C-2(+). A quasimolecular approach is employed to calculate charge transfer and target excitation cross sections. First-order time-dependent perturbation and statistical methods are used to treat the postcollisional processes: the calculated rate constants for C-2 and C-2(+) emission from the excited and charged fullerene are then used to evaluate the fragmentation dynamics. We show that the target ionization cross section decreases with the induced target charge state and the impact energy. C-2 emission from C-60(q+) is found to dominate when q <= 2 while C-2(+) emission dominates when q >= 5, in agreement with the present and previous experimental results.
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| 66. |
- De La Vega Elena, Carlos D., et al.
(författare)
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A rare blood group: p phenotype
- 2009
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Ingår i: Medicina. - 1648-9144. ; 69:6, s. 651-654
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Tidskriftsartikel (refereegranskat)abstract
- A rare blood group: p phenotype. A rare blood group is usually defined as the absence of a high prevalence antigen or the absence of several antigens within a single blood group system. These individuals may develop clinically significant red cell antibodies to the high incidence red cell antigens they lack. A 33-year-old alloimmunized woman was referred to our center at the 12th week of her third pregnancy for evaluation and follow up. The laboratory work-up grouped her as belonging to "p" phenotype, associated with difficulties to find compatible blood for transfusion and a high incidence of recurrent miscarriage. At 36 weeks, a baby girl was born by induced labor due to fetal suffering. With a negative direct antiglobulin test but a positive elution test, she was in the neonatology ward for one week receiving luminotherapy. Homozygosity for a missense mutation at position 752 (c.752C > T) in the A4GALT gene was found to be responsible for the p phenotype. This mutation changes a proline to a leucine at codon 251 of the 4-alpha-galactosyltransferase. Recently, due to an imminent chirurgical intervention and the impossibility to have compatible blood available for transfusion. an autologous donation plan was designed to satisfy probable demand. This case showed the need for blood bank facilities capable to respond satisfactorily to these situations in Argentina. This would facilitate the storage of cryopreserved blood from individuals with rare blood groups for homologous use or to develop rare blood donors programs.
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| 67. |
- del Campo, Sergio Martin, et al.
(författare)
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FPGA prototype of machine learning analog-to-feature converter for event-based succinct representation of signals
- 2013
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Ingår i: IEEE International Workshop on Machine Learning for Signal Processing. - Piscataway, NJ : IEEE Signal Processing Society.
-
Konferensbidrag (refereegranskat)abstract
- Sparse signal models with learned dictionaries of morphological features provide efficient codes in a variety of applications. Such models can be useful to reduce sensor data rates and simplify the communication, processing and analysis of information, provided that the algorithm can be realized in an efficient way and that the signal allows for sparse coding. In this paper we outline an FPGA prototype of a general purpose "analog-to-feature converter", which learns an overcomplete dictionary of features from the input signal using matching pursuit and a form of Hebbian learning. The resulting code is sparse, event-based and suitable for analysis with parallel and neuromorphic processors. We present results of two case studies. The first case is a blind source separation problem where features are learned from an artificial signal with known features. We demonstrate that the learned features are qualitatively consistent with the true features. In the second case, features are learned from ball-bearing vibration data. We find that vibration signals from bearings with faults have characteristic features and codes, and that the event-based code enable a reduction of the data rate by at least one order of magnitude.
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| 68. |
- del Peso-Santos, Teresa, et al.
(författare)
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Coregulation by phenylacetyl-coenzyme A-responsive PaaX integrates control of the upper and lower pathways for catabolism of styrene by Pseudomonas sp. strain Y2.
- 2006
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Ingår i: J Bacteriol. - 0021-9193. ; 188:13, s. 4812-21
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Tidskriftsartikel (refereegranskat)abstract
- The P(styA) promoter of Pseudomonas sp. strain Y2 controls expression of the styABCD genes, which are required for the conversion of styrene to phenylacetate, which is further catabolized by the products of two paa gene clusters. Two PaaX repressor proteins (PaaX1 and PaaX2) regulate transcription of the paa gene clusters of this strain. In silico analysis of the P(styA) promoter region revealed a sequence located just within styA that is similar to the reported PaaX binding sites of Escherichia coli and the proposed PaaX binding sites of the paa genes of Pseudomonas species. Here we show that protein extracts from some Pseudomonas strains that have paaX genes, but not from a paaX mutant strain, can bind and retard the migration of a P(styA) specific probe. Purified maltose-binding protein (MBP)-PaaX1 fusion protein specifically binds the P(styA) promoter proximal PaaX site, and this binding is eliminated by the addition of phenylacetyl-coenzyme A. The sequence protected by MBP-PaaX1 binding was defined by DNase I footprinting. Moreover, MBP-PaaX1 represses transcription from the P(styA) promoter in a phenylacetyl-coenzyme A-dependent manner in vitro. Finally, the inactivation of both paaX gene copies of Pseudomonas sp. strain Y2 leads to a higher level of transcription from the P(styA) promoter, while heterologous expression of the PaaX1 in E. coli greatly decreases transcription from the P(styA) promoter. These findings reveal a control mechanism that integrates regulation of styrene catabolism by coordinating the expression of the styrene upper catabolic operon to that of the paa-encoded central pathway and support a role for PaaX as a major regulatory protein in the phenylacetyl-coenzyme A catabolon through its response to the levels of this central metabolite.
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| 69. |
- Dillman, Karen L., et al.
(författare)
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New records, range extensions and nomenclatural innovations for lichens and lichenicolous fungi from Alaska, USA
- 2012
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Ingår i: Herzogia. - : Herzogia. - 0018-0971. ; 25:2, s. 177-210
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Tidskriftsartikel (refereegranskat)abstract
- New records, range extensions and nomenclatural innovations for lichens and lichenicolous fungi from Alaska, U.S.A. - Herzogia 25: 177-210. Surveys of lichens and lichenicolous fungi have been taking place in the U.S. state of Alaska for more than 160 years, but until now assessing the full extent of their diversity has been hampered by the lack of a comprehensive and synonymized baseline inventory. In this paper we will begin to redress this by resolving outstanding nomenclatural issues and providing voucher data for a forthcoming catalog of Alaskan lichens, specifically: 1) synonymization,and/or resolution of status of species previously reported from Alaska, with emphasis on Alaskan types; 2) species new to the Alaska lichen biota; and 3) biogeographically significant new records from within Alaska. We report 91 species new to the flora of Alaska, including 65 lichens, three saprophytic calicioid fungi and 23 lichenicolous fungi. Of these, we report thirteen species, Biatora sphaeroidiza, Biatorella conspurcans, Chaenothecopsis arthoniae, Collemopsidium foveolatum, Dactylospora frigida, Halospora discrepans, Lecanora bryopsora, Opegrapha geographicola, Peltigera lyngei, Petractis clausa, Protoblastenia cyclospora, Thelocarpon impressellum and Usnea cylindrica as new to North America. In addition, Arthonia pruinata and Flavocetraria minuscula are new to Canada and Adelococcus alpestris new to the United States. We further place the following five names into synonymy: Lecania disceptans (Nyl.) Lynge [= Halecania alpivaga (Th.Fr.) M.Mayrhofer], Lecidea pallidella Nyl. [= Lecania subfuscula (Nyl.) S.Ekman], Lempholemma triptodes (Nyl.) Zahlbr. Leciophysma finmarkicum Th.Fr.), Polyblastia obtenta (Nyl.) Lynge [= Sporodictyon terrestre (Th.Fr.) S.Savic & Tibell], and Verrucaria pernigrata Nyl. [= Protothelenella sphinctrinoides (Nyl.) H.Mayrhofer & Poelt]. We propose restoring the long overlooked taxon Polyblastia exalbida (Nyl.) Zahlbr., currently known only from Alaska, to the North American lichen checklist. Finally, we propose the new combination Puttea caesia (Fr.) M.Svensson & T.Sprib. to replace Lecidea symmictella Nyl., which becomes a synonym.
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| 70. |
- Divakar, Pradeep K., et al.
(författare)
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Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi
- 2015
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 208:4, s. 1217-1226
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Tidskriftsartikel (refereegranskat)abstract
- We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.
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