47 research outputs found
Benefit of Extended Dual Antiplatelet Therapy Duration in Acute Coronary Syndrome Patients Treated with Drug Eluting Stents for Coronary Bifurcation Lesions (from the BIFURCAT Registry)
Two-Year clinical outcomes after coronary bifurcation stenting in older patients from Korea and Italy
BackgroundOlder patients who treated by percutaneous coronary intervention (PCI) are at a higher risk of adverse cardiac outcomes. We sought to investigate the clinical impact of bifurcation PCI in older patients from Korea and Italy.MethodsWe selected 5,537 patients who underwent bifurcation PCI from the BIFURCAT (comBined Insights from the Unified RAIN and COBIS bifurcAtion regisTries) database. The primary outcome was a composite of target vessel myocardial infarction, clinically driven target lesion revascularization, and stent thrombosis at two years.ResultsIn patients aged ≥75 years, the mean age was 80.1 ± 4.0 years, 65.2% were men, and 33.7% had diabetes. Older patients more frequently presented with chronic kidney disease (CKD), severe coronary calcification, and left main coronary artery disease (LMCA). During a median follow-up of 2.1 years, older patients showed similar adverse clinical outcomes compared to younger patients (the primary outcome, 5.7% vs. 4.5%; p = 0.21). Advanced age was not an independent predictor of the primary outcome (p = 0.93) in overall patients. Both CKD and LMCA were independent predictors regardless of age group.ConclusionsOlder patients (≥75 years) showed similar clinical outcomes to those of younger patients after bifurcation PCI. Advanced age alone should not deter physicians from performing complex PCIs for bifurcation disease
Biochar successfully replaces activated charcoal for in vitro culture of two white poplar clones reducing ethylene concentration
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Global maps of soil temperature
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
Global maps of soil temperature
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
AI is a viable alternative to high throughput screening: a 318-target study
: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery
Global maps of soil temperature.
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
Black holes, gravitational waves and fundamental physics: a roadmap
The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions.
The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature.
The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'
Electrochemical approaches to Atom Transfer Radical Polymerization
Controlled radical polymerizations (CRPs) are among the most powerful methods to obtain polymers with well-defined properties and high commercial value. Atom transfer radical polymerization (ATRP) is probably the most widely used CRP, in academia and industry, thanks to its versatility and simplicity. In ATRP, a metal complex in a low oxidation state, MtzLm (typically a copper-amine system, [CuIL]+) reacts with a dormant polymeric chain Pn–X (where X = Cl, Br) to produce radicals Pn• that can propagate, in the bulk of the solution, by addition to monomer units. In this reaction, the copper complex is oxidized and binds to X–, generating the deactivating species [X-CuIIL]+, which traps the propagating species. ATRP equilibrium is shifted towards the dormant species Pn-X, so that Pn• concentration is very low, and the probability of radical-radical termination events is minimized. Growth of all chains begins virtually at the same time, thanks to the use of alkyl halide (RX) initiators that are more reactive than the dormant species, Pn-X. In such conditions, chain growth is homogenous, and it is possible to obtain polymers with predetermined molecular weight, narrow molecular-weight distribution and high chain-end fidelity. ATRP allows to tailor macromolecules with specific compositions, architectures and position of functional groups.
The aim of this thesis is to contribute to both the understanding and development of ATRP catalyzed by copper complexes, using electrochemical methods as equally analytical tools and efficient means of triggering and controlling the polymerization. The work focused on spreading the use of such systems to efficiently control the polymerization of a series of important monomers. Moreover, the investigated ATRP systems can be considered also “green” for several reasons: (i) most of the work regards the study and development of the reaction in green solvents in which copper complexes generally have high catalytic activity; (ii) electrochemical methods for catalyst regeneration (electrochemically mediated ATRP, eATRP) allowed triggering the polymerization with low loadings of copper complexes; (iii) ionic liquids, a class of non-flammable and easily recyclable solvents, were explored as potential media for eATRP; (iv) the mechanism of catalytic halogen exchange was investigated and defined, abridging the synthesis of block copolymers.
ATRP catalysts were investigated in the ionic liquid 1-butyl-3-methylimidazolium triflate ([BMIm][OTf]). Both Cu/L speciation and reactivity were found to be suitable for a well-controlled polymerization process. Polymerizations were conducted with electrochemical (re)generation of the active [CuIL]+ complex (eATRP). eATRP of methyl acrylate was investigated in detail by varying a series of parameters such as applied potential, temperature, degree of polymerization and catalyst load ([CuIITPMA]2+, TPMA = tris(2-pyridylmethyl)amine). Application of an electrochemical switch and chain extension with acrylonitrile via catalytic halogen exchange (cHE) proved the livingness of the polymerizations. Experiments triggered in recycled ionic liquid proved that eATRP tolerates well the recycled solvent; polymerizations exhibited good control and high conversion.
Block copolymers (BCP) have relevance in a vast range of applications in everyday life. BCP of acrylonitrile (AN) and butyl acrylate (BA) were investigated as precursors for mesoporous carbons. Thus, eATRP of acrylonitrile was studied considering several aspects, including the effect of applied potential, degree of polymerization, C-X nature and initiator structure. A macroinitiator of PAN was then extended with BA to form PAN-b-PBA copolymer as a precursor for mesoporous carbons. BCP can be obtained also by extension of a PBA chain with AN via cHE, thus avoiding purification procedures and reactivity mismatch when crossing from a less reactive monomer to a more reactive one.
cHE was proved to be an efficient tool of polymerization by both SARA and eATRP, in a range of solvents, including water. Methyl methacrylate (MMA) was polymerized thanks to cHE in [BMIm][OTf] and ethanol, to solve the issue of penultimate effect. Fine tuning of the electrolysis conditions afforded PMMA with low dispersion. Further improvements were obtained by using [CuIIPMDETA]2+ as an inexpensive and efficient catalyst in alternative to [CuIITPMA]2+. Tacticity analysis of PMMA obtained in [BMIm][OTf] and ethanol confirmed the poor ability of the ionic solvent to induce stereocontrol to the polymerization.
Pyridinic complexes such as [CuIITPMA]2+ are stable in very acid conditions (pH = 1). This allowed unprecedented control over conditions of macromolecular growth in water. In addition, it opened a new avenue for the polymerization of ionic liquid monomers (ILMs), a class of building blocks that can give a plethora of new materials. The main reason preventing ATRP of ILM is a cyclization reaction involving the chain-end with the terminal halogen as a leaving group, as in the case of methacrylic acid. Application of three strategies previously developed for ATRP of methacrylic acid allowed to dramatically improve conversion and control over ILMs polymerization. (i) Using C-Cl chain end functionality, which is much more stable than C-Br, (ii) lowering further the pH to completely convert free carboxylate ions to carboxylic acid, which is a much weaker nucleophile, and (iii) enhancing the polymerization rate to avoid the negative contribution of the cyclization side reaction, allowed synthesis of well-controlled high molecular weight poly(ionic liquids), PILs, with degree of polymerization > 500. A simple (poly)halogenated organic initiator such as 2,2-dichloropropionic acid was used to produce linear homotelechelic PILs.
Electrochemically mediated ATRP allowed exceptional control over CuI (re)generation. For this reason, it was decided to study the eATRP of vinyl chloride, which was considered impossible until now. The polymerization, triggered in a pressure-resistant electrochemical reactor, was controlled, fast and afforded an acceptable conversion. In addition to linear PVC, a star PVC was also synthesized, highlighting the flexibility of eATRP. In the star architecture, the electrochemical polymerization was by far superior to the chemical one (SARA ATRP). The success of this polymerization has categorically denied the SET-LRP mechanism and its assumptions.
One of the crucial properties of electrochemical eATRP is the inert role played by the cathode material used for the regeneration of [CuIL]+. Any electrode material with good stability in the reaction medium can be used as a cathode. It was therefore decided to study the polymerization of an acrylate using the surface of a stainless steel (SS304) reactor exposed to the polymerization mixture as a cathode. In this way, the reactor has the dual function of electrode and place where the reaction takes place. The results showed that polymerization is fast, controlled and reaches high conversions. Moreover, the absence of release of metal ions during the reaction (Fe, Ni, Cr) confirmed that the polymerization takes place via electrochemical reduction of CuII to CuI, while SS304 acts only as an electron reservoir, not chemically involved in ATRP activation. Such simple and cheap electrochemical setup can make the scale-up of the eATRP a reality in the short term and open new economic prospects.Le polimerizzazioni radicaliche controllate (CRP) sono riconosciute come i metodi più potenti per ottenere polimeri con struttura macromolecolare ben definita e alto valore commerciale. La polimerizzazione radicalica a trasferimento atomico (ATRP) è probabilmente la CRP più utilizzata, in accademia e industria, grazie alla sua versatilità e semplicità. Nell’ATRP, un complesso metallico a basso stato di ossidazione, MtzLm (tipicamente un sistema rame-ammina, [CuIL]+) reagisce con una catena polimerica dormiente Pn-X (dove X = Cl, Br) per produrre radicali Pn•. Questi propagando nel bulk della soluzione, crescono aggiungendo unità monomeriche. In questo processo, il complesso di rame viene ossidato e si lega a X-, generando la specie disattivante [X-CuIIL]+, che intrappola la specie propagante. L'equilibrio di ATRP è fortemente spostato verso la specie dormiente Pn-X, cosicché la concentrazione di radicali sia molto bassa e la probabilità di eventi di terminazione bimolecolare sia ridotta al minimo. La crescita inizia praticamente allo stesso tempo per tutte le catene grazie a iniziatori (alogenuro alchilico) molto efficienti (RX). In tali condizioni, la crescita delle catene è omogenea ed è possibile ottenere polimeri con peso molecolare predeterminato, distribuzione stretta dei pesi molecolari e alta ritenzione della funzionalità di fine catena. L’ATRP consente di costruire dunque macromolecole con specifiche composizioni, architetture e posizionamento dei gruppi funzionali.
Lo scopo di questa tesi è di contribuire alla comprensione e allo sviluppo dell’ATRP catalizzata da complessi di rame, utilizzando metodi elettrochimici sia come strumenti analitici che come strumenti per eseguire e controllare la polimerizzazione. Il lavoro si è concentrato sulla diffusione dell'uso di tali sistemi per controllare in modo efficiente la polimerizzazione di una serie di monomeri rilevanti. I sistemi investigati per ATRP possono essere considerati anche "green" per diversi motivi: (i) la maggior parte del lavoro riguarda lo studio e lo sviluppo della reazione in solventi green, generalmente caratterizzati da un'elevata attività catalitica; (ii) i metodi elettrochimici per la rigenerazione del catalizzatore (ATRP mediata elettrochimicamente, eATRP) permette la polimerizzazione con limitata quantità di complessi di rame; (iii) i liquidi ionici, una nuova classe di solventi non infiammabili e facilmente riciclabili, sono stati esplorati come potenziali solventi per eATRP; (iv) il meccanismo di halogen exchange catalitico (cHE) è stato studiato e sviluppato, facilitando la sintesi di copolimeri a blocchi.
I catalizzatori ATRP sono stati studiati nel liquido ionico 1-butil-3-metilimidazolio triflato. Sia la speciazione che la reattività di Cu/L sono risultate in linea per un processo di polimerizzazione ben controllato. Le polimerizzazioni sono state condotte con la (ri)generazione elettrochimica del complesso attivo [CuIL]+ (eATRP). L'eATRP del metil acrilato è stata studiata in dettaglio variando una serie di parametri come: potenziale applicato, temperatura, grado di polimerizzazione e carico di catalizzatore di Cu/TPMA (TPMA = tris(2-piridilmetil)ammina). Un interruttore elettrochimico e l'estensione della catena con acrilonitrile (grazie al meccanismo di halogen exchange catalitico) hanno dimostrato la presenza della funzionalità di fine catena. Le polimerizzazioni ottenute tramite liquido ionico riciclato hanno dimostrato che eATRP tollera bene anche un solvente riciclato.
I copolimeri a blocchi (BCP) hanno rilevanza in una vasta gamma di applicazioni nella vita di tutti i giorni. BCP di acrilonitrile (AN) e butil acrilato (BA) sono stati studiati come precursori di carbonio mesoporoso. Pertanto, eATRP di acrilonitrile è stata introdotta e studiata nei diversi aspetti, come: effetto del potenziale applicato, del grado di polimerizzazione, della natura di C-X e della struttura dell'iniziatore. Un macroiniziatore di PAN è stato quindi esteso con BA per formare il copolimero PAN-b-PBA come precursore del carbonio mesoporoso. I BCP possono essere ottenuti anche via cHE, evitando così le procedure di purificazione e la differenza di reattività quando si passa da un monomero meno reattivo a uno più reattivo.
Il cHE si è dimostrato strumento efficace di polimerizzazione sia da SARA che da eATRP, in una gamma di solventi incluso DMSO e acqua. Il metil metacrilato (MMA) è stato polimerizzato grazie al cHE in liquido ionico ed etanolo, per risolvere il problema dell’effetto del penultimo. La messa a punto delle condizioni di elettrolisi ha permesso di ottenere PMMA a bassa dispersione. Ulteriori miglioramenti sono stati ottenuti utilizzando [CuIIPMDETA]2+ come catalizzatore come alternativa economica ed efficiente a Cu/TPMA. L'analisi della tatticità del PMMA ottenuta in [BMIm][OTf] e l'etanolo ha confermato la scarsa capacità del solvente ionico di indurre stereocontrollo durante la polimerizzazione.
I complessi piridinici, come Cu/TPMA, stabili fino a condizioni molto acide (pH ⁓1) hanno permesso di ottenere poli(liquidi ionici). Hanno aperto infatti una nuova strada per la polimerizzazione di monomeri liquidi ionici, una classe di molecole che può dare una pletora di nuovi materiali polimerizzati mediante ATRP. La ragione principale che impedisce l'ATRP di ILM è una reazione di ciclizzazione che coinvolge l'estremità della catena, con l'alogeno terminale come gruppo uscente, come nel caso dell'acido metacrilico. Le stesse tre strategie usate per l’acido metacrilico hanno permesso di migliorare drasticamente la conversione e il controllo sulla polimerizzazione di ILM: (i) usando la funzionalità di fine catena C-Cl, che è molto più stabile di C-Br; (ii) abbassando il pH per convertire completamente gli ioni carbossilato liberi in acido carbossilico, che è un nucleofilo molto più debole; (iii) migliorare la velocità di polimerizzazione per evitare il contributo negativo della reazione di ciclizzazione. Tali condizioni hanno permesso la sintesi di poli(liquidi ionici) (PIL) ben controllati ad alto peso molecolare fino a grado di polimerizzazione 1000. Un semplice iniziatore organico (poli)alogenato come acido 2,2-dicloropropionico è stato utilizzato per produrre un PIL lineare telechelico.
L’insieme di questi risultati può consentire una più facile implementazione e scalabilità industriale dell’eATRP. Per questo motivo, è stato deciso di studiare l’eATRP del cloruro di vinile, considerata finora impossibile. La polimerizzazione, effettuata in un reattore elettrochimico resistente alla pressione, è controllata, veloce e con una conversione buona in tempi ragionevoli. Oltre al classico PVC lineare, è stato anche sintetizzato un PVC a stella, evidenziando la flessibilità dell'eATRP. Nell'architettura a stella, la polimerizzazione elettrochimica si è dimostrata di gran lunga superiore a quella chimica (SARA ATRP). Il successo di questa polimerizzazione ha smentito il meccanismo SET-LRP e le sue assunzioni.
Una delle proprietà dell’eATRP è la tolleranza al materiale catodico utilizzato per la rigenerazione di [CuIL]+. Si è deciso dunque di studiare la polimerizzazione di un acrilato usando la superficie del reattore esposto alla miscela di polimerizzazione come elettrodo. In questo modo il reattore ha la duplice funzione di elettrodo e luogo fisico in cui avviene la reazione. I risultati hanno mostrato che la polimerizzazione è veloce e controllata, raggiungendo conversioni elevate in breve tempo. Inoltre, l'assenza di rilascio di ioni metallici durante la reazione (Fe, Ni, Cr) da parte dell’acciaio conferma che la polimerizzazione avviene elettrochimicamente, l'acciaio agisce solo come un serbatoio di elettroni e non è chimicamente coinvolto. Una tale impostazione elettrochimica, semplice ed economica, può rendere l'eATRP una tecnica commerciale a breve termine e aprire nuove prospettive economiche