Influence of the Framework Topology on the Reactivity of Chiral Pyrrolidine Units Inserted in Different Porous Organosilicas

[EN] Three families of organosiliceous materials with different structuration level, order, and textural properties (non-ordered, M41S, and SBA-15 type materials) were prepared incorporating in their structural framework chiral pyrrolidine units with variable content. Likewise, non-ordered mesoporous hybrid solids were obtained through a sol-gel process in a fluoride medium, while M41S and SBA-15 type materials were obtained through micellar routes in the presence of long-chain neutral surfactants or block copolymers. Thanks to appropriate characterization studies and catalytic tests for the Michael addition between butyraldehyde and beta-nitrostyrene, we showed how the void shapes and sizes present in the structure of hybrid materials control the diffusion of reactants and products, as well as confine transition states and reactive intermediates. The best catalytic results, considering activity and enantioselectivity, were achieved in the presence of a non-ordered material, NOH-Pyr-5%, which exhibited the highest Brunauer-Emmett-Teller (BET) area, with a 96% yield and a 82% ee for the Michael adduct.This research was funded by the Spanish Government(MAT2017-82288-C2-1-P), Severo Ochoa Excellence Program (SEV-2016-0683), and MULTY2HYCAT (EU-Horizon 2020 funded project under grant agreement no. 720783). S. Ll. is thankful for the predoctoral fellowship from MINECO for financial support (BES-2015-072627).Llopis-Perez, S.; Velty, A.; Díaz Morales, UM. (2019). Influence of the Framework Topology on the Reactivity of Chiral Pyrrolidine Units Inserted in Different Porous Organosilicas. Catalysts. 9(8):1-21. https://doi.org/10.3390/catal9080654S12198Kuschel, A., Drescher, M., Kuschel, T., & Polarz, S. (2010). Bifunctional Mesoporous Organosilica Materials and Their Application in Catalysis: Cooperative Effects or Not? Chemistry of Materials, 22(4), 1472-1482. doi:10.1021/cm903412eDíaz, U., Brunel, D., & Corma, A. (2013). Catalysis using multifunctional organosiliceous hybrid materials. Chemical Society Reviews, 42(9), 4083. doi:10.1039/c2cs35385gKadib, A. E., Molvinger, K., Guimon, C., Quignard, F., & Brunel, D. (2008). Design of Stable Nanoporous Hybrid Chitosan/Titania as Cooperative Bifunctional Catalysts. Chemistry of Materials, 20(6), 2198-2204. doi:10.1021/cm800080sHorcajada, P., Serre, C., Vallet-Regí, M., Sebban, M., Taulelle, F., & Férey, G. (2006). Metal–Organic Frameworks as Efficient Materials for Drug Delivery. Angewandte Chemie International Edition, 45(36), 5974-5978. doi:10.1002/anie.200601878Zhang, J., Han, X., Wu, X., Liu, Y., & Cui, Y. (2019). Chiral DHIP- and Pyrrolidine-Based Covalent Organic Frameworks for Asymmetric Catalysis. ACS Sustainable Chemistry & Engineering, 7(5), 5065-5071. doi:10.1021/acssuschemeng.8b05887Loy, D. A., & Shea, K. J. (1995). Bridged Polysilsesquioxanes. Highly Porous Hybrid Organic-Inorganic Materials. Chemical Reviews, 95(5), 1431-1442. doi:10.1021/cr00037a013Inagaki, S., Guan, S., Fukushima, Y., Ohsuna, T., & Terasaki, O. (1999). Novel Mesoporous Materials with a Uniform Distribution of Organic Groups and Inorganic Oxide in Their Frameworks. Journal of the American Chemical Society, 121(41), 9611-9614. doi:10.1021/ja9916658Villaverde, G., Arnanz, A., Iglesias, M., Monge, A., Sánchez, F., & Snejko, N. (2011). Development of homogeneous and heterogenized rhodium(i) and palladium(ii) complexes with ligands based on a chiral proton sponge building block and their application as catalysts. Dalton Transactions, 40(37), 9589. doi:10.1039/c1dt10597cMelde, B. J., Holland, B. T., Blanford, C. F., & Stein, A. (1999). Mesoporous Sieves with Unified Hybrid Inorganic/Organic Frameworks. Chemistry of Materials, 11(11), 3302-3308. doi:10.1021/cm9903935García-García, P., Moreno, J. M., Díaz, U., Bruix, M., & Corma, A. (2016). Organic–inorganic supramolecular solid catalyst boosts organic reactions in water. Nature Communications, 7(1). doi:10.1038/ncomms10835Moreno, J. M., Velty, A., Díaz, U., & Corma, A. (2019). Synthesis of 2D and 3D MOFs with tuneable Lewis acidity from preformed 1D hybrid sub-domains. Chemical Science, 10(7), 2053-2066. doi:10.1039/c8sc04372hSzőllősi, G., Gombkötő, D., Mogyorós, A. Z., & Fülöp, F. (2018). Surface-Improved Asymmetric Michael Addition Catalyzed by Amino Acids Adsorbed on Laponite. Advanced Synthesis & Catalysis, 360(10), 1992-2004. doi:10.1002/adsc.201701627Feng, J., Li, X., & Cheng, J.-P. (2017). Enantioselective Organocatalyzed Vinylogous Michael Reactions of 3-Alkylidene Oxindoles with Enals. The Journal of Organic Chemistry, 82(3), 1412-1419. doi:10.1021/acs.joc.6b02582Bernardi, L., Fochi, M., Carbone, R., Martinelli, A., Fox, M. E., Cobley, C. J., … Carlone, A. (2015). Organocatalytic Asymmetric Conjugate Additions to Cyclopent-1-enecarbaldehyde: A Critical Assessment of Organocatalytic Approaches towards the Telaprevir Bicyclic Core. Chemistry - A European Journal, 21(52), 19208-19222. doi:10.1002/chem.201503352Afewerki, S., Ma, G., Ibrahem, I., Liu, L., Sun, J., & Córdova, A. (2015). Highly Enantioselective Control of Dynamic Cascade Transformations by Dual Catalysis: Asymmetric Synthesis of Polysubstituted Spirocyclic Oxindoles. ACS Catalysis, 5(2), 1266-1272. doi:10.1021/cs501975uMonge-Marcet, A., Pleixats, R., Cattoën, X., Man, M. W. C., Alonso, D. A., & Nájera, C. (2011). Prolinamide bridged silsesquioxane as an efficient, eco-compatible and recyclable chiral organocatalyst. New Journal of Chemistry, 35(12), 2766. doi:10.1039/c1nj20516aSagamanova, I., Rodríguez-Escrich, C., Molnár, I. G., Sayalero, S., Gilmour, R., & Pericàs, M. A. (2015). Translating the Enantioselective Michael Reaction to a Continuous Flow Paradigm with an Immobilized, Fluorinated Organocatalyst. ACS Catalysis, 5(11), 6241-6248. doi:10.1021/acscatal.5b01746Betancort, J. M., & Barbas, C. F. (2001). Catalytic Direct Asymmetric Michael Reactions:  Taming Naked Aldehyde Donors. Organic Letters, 3(23), 3737-3740. doi:10.1021/ol016700

Active Base Hybrid Organosilica Materials based on Pyrrolidine Builder Units for Fine Chemicals Production

[EN] The catalytic activity of "pyrrolidine type" fragments included or anchored in the mesoporous silica supports or polymeric frameworks have been fully reported for enantioselective transformation. Nevertheless, low attention was focused on their catalytic abilities to perform base-catalyzed reaction. Accordingly, hybrid materials including pyrrolidine fragments in the mesoporous silica supports were prepared following different synthesis methods, such as micellar and fluoride sol-gel routes in absence of structural directing agents. Their great catalytic performance was explored for various base-catalyzed reactions to the formation of C-C bond through Knoevenagel, Claisen-Schmidt and Henry condensations under microwave irradiation. The benefits of microwave irradiation combined with suitable catalytic properties of pyrrolidine hybrid materials with strong base sites and high accessibility to active centers, allowed carrying out successfully base-catalyzed condensation reactions for the production of fine chemicals. Moreover, the hybrid catalyst exhibited high selectivity and good stability over different catalytic cycles contributing to environmental sustainability.The authors are grateful for financial support from the Spanish Government, MAT2017-82288-C2-1-P and PID2020112590GB C21/AEI/10.13039/501100011033, and MULTY2HYCAT European project (EUHorizon 2020 funded project under grant agreement no. 720783).Llopis-Perez, S.; Velty, A.; Díaz Morales, UM. (2021). Active Base Hybrid Organosilica Materials based on Pyrrolidine Builder Units for Fine Chemicals Production. ChemCatChem. 13(23):5012-5024. https://doi.org/10.1002/cctc.202101031S50125024132

Estudio de la proteína transportadora de la hormona de crecimiento en los transtornos del crecimiento y en las alteraciones de la nutrición

Consultable des del TDXTítol obtingut de la portada digitalitzad

Integrating Blockchain in safety-critical systems: an application to the nuclear industry

Safety-Critical Systems (SCSs) often manage sensible data that must be trustworthy, especially in many cases in which different actors participate whose interests may not coincide. Blockchain is a disruptive technology that has emerged to ensure the trustfulness of data. The nuclear industry incorporates many SCSs where blockchain can be applied. This paper focuses on the use of blockchain for the inspection of steam generators of a nuclear power plant. This is a critical process where different actors participate: plant property, external companies in charge of the inspection itself and different administrations. It typically consists of a number of processes that explore the state of different components of the plant in order to find any kind of failure or defect and it generates a great amount of data that must be verifiable and trustworthy. A distributed blockchain-based system is presented where all the nodes share the information and it cannot be altered. As a novelty, automatic inspection algorithms are stored in the blockchain itself by means of smart contracts. The benefits of blockchain are studied for the nuclear industry in general and for the inspection process in particular. In order to explore the possible drawbacks of a blockchain-based system for data management, a simulator has been implemented to recreate the scenario of an inspection. The results obtained show that blockchain architectures are a good alternative to traditional information repositories for nuclear power plant inspections

Wireless sensor networks and structural health monitoring: Experiences with slab track infrastructures

Slab track systems have the potential to become a more sustainable option for high-speed railway infrastructures than traditional ballasted tracks. Traditionally, the systems that monitor these infrastructures have been costly, but advances in the last few decades have made the use of wireless sensor networks within these infrastructures a feasible solution that can be used to evaluate their degradation for failure detection and prediction. Since the cost of these systems is steadily decreasing, it is now possible to use permanent wireless sensor networks as an integral part of the overall system to pave the way for smart infrastructures that can get real-time information about the structural health of the infrastructure at a relatively low cost. In order to show the suitability of this kind of system to monitor the structural health, three demonstrators, developed in the context of the FASTRACK project, related to the design and construction of a monitoring system for slab track systems that measures vibrations and displacements in the track, are presented. FASTRACK uses an innovative approach where data read by sensors are sent to passing trains, which are used as data mules to upload the information to a remote server. On arrival at the station, the data are stored in a database, which is queried by an application to extract relevant information by means of analysis algorithms to detect and predict failures. The first real scenario tests the limits of the system under stress situations. The second one tests the system in an actual, installed slab track to analyze the suitability of the communication architecture and to study a transition zone between slab tracks to a ballast track. The last scenario deals with the data mule performance tests

Pattern Dystrophy of the Macula in a Case of Steinert Disease

IntroductionMyotonic dystrophies are typically associated with ocular complications like ptosis, weakness of the ocular muscle and cataracts, but also with less recognized retinal changes.Case ReportA 41-year-old female with type 1 myotonic dystrophy complained of progressive vision loss. Slit lamp examination revealed the presence of typical bilateral polychromatic cataract with posterior subcapsular component. Dilated fundus examination was remarkable for bilateral macular depigmented changes. Multimodal imaging analysis of the macula suggested the presence of a butterfly-shaped pattern dystrophy.DiscussionIn cases of myotonic dystrophies it is of great relevance to analyze the presence of retinal changes that might limit the visual improvement following cataract extraction

Rituximab in refractory Vogt–Koyanagi–Harada disease

IntroductionVogt–Koyanagi–Harada (VKH) prognosis depends on early recognition and treatment; chronic disease may be developed when either delayed or inadequate treatment is performed, whereas other cases despite correct treatment are refractory to different drugs and also become chronic. We report a case of refractory VKH controlled with rituximab treatment.Case reportA 41-year-old female with painful visual loss and headache was examined. (VA 0.4 in RE and hand movements (HM) in LE). Retinal examination demonstrated multiple serous retinal detachments in both eyes. High-dose oral steroids were started, followed by progressive tapering of prednisone. New acute anterior and posterior relapses were achieved, and other immunommodulators were progressively added—new high-dose steroid treatment, adalimumab, cyclosporine, and methotrexate—but patient had new anterior and posterior recurrences associated with tinnitus and headache. Thus, an infusion of 1 g of rituximab was administered after 15 months follow-up; the VA was 0.2 in RE and counting fingers in LE. Three additional doses of 1 g each were administered 1, 6, and 16 months later. We have achieved a final VA after 34 months follow-up of 0.2 in RE and HM in LE, with definitive control of inflammation, without acute relapses since rituximab was administered.ConclusionAfter searching PubMed/Medline, this is the first report of VKH disease treated with rituximab. Additional studies are warranted to confirm the efficacy of this new approach for inflammatory control in refractory cases of VKH disease

Adult Coats’ Disease Successfully Managed with the Dexamethasone Intravitreal Implant (Ozurdex®) Combined with Retinal Photocoagulation

Purpose: To report a case of Coats’ disease managed with the dexamethasone intravitreal implant Ozurdex® (Allergan, Inc., Irvine, Calif., USA) combined with retinal photocoagulation. Methods: A 46-year-old female with 20/200 visual acuity was diagnosed with Coats’ disease with secondary retinal vasoproliferative tumor. An initial approach was performed with an intravitreal injection of the sustained-release dexamethasone implant Ozurdex. After reattachment of the retina, the telangiectatic vessels were treated with laser photocoagulation. Results: The patient’s visual acuity improved to 20/25 after the intravitreal Ozurdex. No further recurrences of exudation were evident through the 12-month follow-up. Conclusions: Ozurdex may be an effective initial therapeutic approach for Coats’ disease with immediate anatomical response and visual improvement

Acute endothelial failure after cosmetic iris implants (NewIris®)

We report a case of an acute endothelial failure after the implantation of a new cosmetic, colored, artificial iris diaphragm implant called NewIris®. A 21-year-old woman came to us complaining of progressive loss of vision and pain after NewIris lenses had been implanted. Decreased visual acuity, corneal edema, and increased intraocular pressure in both eyes appeared only 3 weeks after the surgery. The lenses were removed as soon as possible but had already severely affected the endothelial cell count. NewIris implants are an alternative to cosmetic contact lenses, but they are not as safe as other phakic anterior chamber intraocular lenses, nor are they a good option for the patient