617 research outputs found
Allocation of Ambipolar Charges on an Organic Diradical with a Vinylene–Phenylenediyne Bridge
Two redox and magnetically active perchlorotriphenylmethyl (•PTM) radical units have been connected as end-capping groups to a bis(phenylene)diyne chain through vinylene linkers. Negative and positive charged species have been generated, and the influence of the bridge on their stabilization is discussed. Partial reduction of the electron-withdrawing •PTM radicals results in a class-II mixed-valence system with the negative charge located on the terminal PTM units, proving the efficiency of the conjugated chain for the electron transport between the two terminal sites. Counterintuitively, the oxidation process does not occur along the electron-rich bridge but on the vinylene units. The •PTM radicals play a key role in the stabilization of the cationic species, promoting the generation of quinoidal ring segments
Stability of radical-functionalized gold surfaces by self-assembly and on-surface chemistry
We have investigated the radical functionalization of gold surfaces with a
derivative of the perchlorotriphenylmethyl (PTM) radical, using two methods: by
chemisorption from the radical solution and by on surface chemical
derivatization from a precursor. We have investigated the obtained
self-assembled monolayers by photon-energy dependent X-ray photoelectron
spectroscopy. Our results show that the molecules were successfully anchored on
the surfaces. The monolayers are characterized by air and beam stability
unprecedented for films of organic radicals. Over very long beam exposure we
observed a dynamic nature of the radical-Au complex. The results clearly
indicate that (mono)layers of PTM; radical derivatives have the necessary
stability to stand device applications
Interrogating the CISS effect in chiral and paramagnetic organic radicals : the impact of the molecular spin over the total spin polarization
Continuous research on new chiral molecular materials brings new exciting properties to the field of molecular electronics. The discovery of the chirality-induced spin selectivity (CISS) effect has expanded the list of applications for chiral structures, opening promising avenues for their exploitation in molecular spintronics. In this work, the persistent propeller-like organic perchlorotriphenylmethyl (PTM) radical is investigated as a potential spin filter combining chirality and paramagnetism. In particular, two different PTM derivatives, mono- and bis-functionalized, with one or two terminal alkyne groups have been used for the preparation of enantioenriched solid-state assemblies. The analysis of their chiroptical properties reveals that the functionalization does not play a crucial role in their final conformational stability and highlights the dissimilarities of the racemization barriers in solution and solid states. Spin-dependent electrochemical and charge transport measurements of enantioenriched PTM-based self-assembled monolayers did not reveal the existence of the CISS effect. Density functional theory quantum transport calculations show that the most dominant contribution to the spin polarization would not be CISS-related polarization, but the one intrinsically associated with the radical spin. Nevertheless, at room temperature this contribution is affected by thermal fluctuations averaging to a net zero spin polarization
Lower expression of plasma-derived exosome miR-21 levels in HIV-1 elite controllers with decreasing CD4 T cell count
Exosome-derived miR-21 was independently associated with CD4 T cell decline in HIV-1-infected elite controllers (OR 0.369, 95% CI 0.137-0.994, p = 0.049). Also, a negative correlation between miR-21 expression and MCP-1 level was found (r = −0.649, p = 0.020), while no correlation between soluble biomarkers or cellular immune activation was found
Recommended from our members
Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Molecular One- and Two-Qubit Systems with Very Long Coherence Times
General-purpose quantum computation and quantum simulation require multi-qubit architectures with precisely defined, robust interqubit interactions, coupled with local addressability. This is an unsolved challenge, primarily due to scalability issues. These issues often derive from poor control over interqubit interactions. Molecular systems are promising materials for the realization of large-scale quantum architectures, due to their high degree of positionability and the possibility to precisely tailor interqubit interactions. The simplest quantum architecture is the two-qubit system, with which quantum gate operations can be implemented. To be viable, a two-qubit system must possess long coherence times, the interqubit interaction must be well defined and the two qubits must also be addressable individually within the same quantum manipulation sequence. Here results are presented on the investigation of the spin dynamics of chlorinated triphenylmethyl organic radicals, in particular the perchlorotriphenylmethyl (PTM) radical, a mono-functionalized PTM, and a biradical PTM dimer. Extraordinarily long ensemble coherence times up to 148 µs are found at all temperatures below 100 K. Two-qubit and, importantly, individual qubit addressability in the biradical system are demonstrated. These results underline the potential of molecular materials for the development of quantum architectures.The authors acknowledge the following funding: Center for Integrated Quantum Science and Technology, Carl Zeiss Foundation, Baden Württemberg Stiftung (QT5), Vector Foundation, Fonds der Chemischen Industrie. The work was also supported by Generalitat de Catalunya 2021 SGR 00443, MICINN (GENESIS PID2019-111682RB-I00), and the “Severo Ochoa” Programme for Centers of Excellence in R&D FUNFUTURE CEX2019-000917-S, CSIC Interdisciplinary Thematic Platform on Quantum Technologies (PTI QTEP+) (20219PT016, QTP2021-03-003). This research is part of the CSIC program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094. The authors further acknowledge financial support from EPSRC (UK) by funding the EPSRC National Research Facility for EPR spectroscopy at Manchester (NS/A000055/1; EP/W014521/1). The authors thank Yannick Thiebes for recording the powder X-ray diffractogram of Figure S15, Supporting Information.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe
Stability of radical-functionalized gold surfaces by self-assembly and on-surface chemistry
We have investigated the radical functionalization of gold surfaces with a derivative of the perchlorotriphenylmethyl (PTM) radical using two methods: by chemisorption from the radical solution and by on-surface chemical derivation from a precursor. We have investigated the obtained self-assembled monolayers by photon-energy dependent X-ray photoelectron spectroscopy. Our results show that the molecules were successfully anchored on the surfaces. We have used a robust method that can be applied to a variety of materials to assess the stability of the functionalized interface. The monolayers are characterized by air and X-ray beam stability unprecedented for films of organic radicals. Over very long X-ray beam exposure we observed a dynamic nature of the radical–Au complex. The results clearly indicate that (mono)layers of PTM radical derivatives have the necessary stability to withstand device applications.The authors would like to thank Helmholtz-Zentrum Berlin (HZB) for providing beamtime at BESSY II (Berlin, Germany), and Hilmar Adler, Elke Nadler, and Sergio Naselli for technical support. J. A. de S. is enrolled in the Materials Science PhD program of UAB. J. A. de S. thanks the Spanish Ministry for an FPI fellowship. This work was funded by the Spanish Ministry project FANCYCTQ2016-80030-R and GENESIS PID2019-111682RB-100, the Generalitat de Catalunya (2017SGR918) and the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centers of Excellence in R&D (SEV-2015-0496), the CSIC with the i-Link+ 2018 (Ref. LINKA20128) and CIBERBBN. Financial support from HZB and German Research Foundation (DFG) under the contract CA852/11-1 is gratefully acknowledged.Peer reviewe
Molecular one‐ and two‐qubit systems with very long coherence times
General-purpose quantum computation and quantum simulation require multi-qubit architectures with precisely defined, robust interqubit interactions, coupled with local addressability. This is an unsolved challenge, primarily due to scalability issues. These issues often derive from poor control over interqubit interactions. Molecular systems are promising materials for the realization of large-scale quantum architectures, due to their high degree of positionability and the possibility to precisely tailor interqubit interactions. The simplest quantum architecture is the two-qubit system, with which quantum gate operations can be implemented. To be viable, a two-qubit system must possess long coherence times, the interqubit interaction must be well defined and the two qubits must also be addressable individually within the same quantum manipulation sequence. Here results are presented on the investigation of the spin dynamics of chlorinated triphenylmethyl organic radicals, in particular the perchlorotriphenylmethyl (PTM) radical, a mono-functionalized PTM, and a biradical PTM dimer. Extraordinarily long ensemble coherence times up to 148 µs are found at all temperatures below 100 K. Two-qubit and, importantly, individual qubit addressability in the biradical system are demonstrated. These results underline the potential of molecular materials for the development of quantum architectures.Center for Integrated Quantum Science and TechnologyCarl Zeiss FoundationVector FoundationFonds der Chemischen IndustrieGeneralitat de Catalunya
http://dx.doi.org/10.13039/501100002809Programme for Centers of Excellence in R&D FUNFUTURECSIC Interdisciplinary Thematic Platform on Quantum TechnologiesRecovery and Resilience Facility of the European UnionEPSRC National Research FacilityBaden Württemberg StiftungProjekt DEA
A Prospective, Multicenter, Real-World Registry of Coronary Lithotripsy in Calcified Coronary Arteries
BACKGROUND Intravascular lithotripsy (IVL) has demonstrated effectiveness in the treatment of calcified lesions in selected patients with stable coronary disease. OBJECTIVES The authors sought to assess the performance of coronary IVL in calcified coronary lesions in a real-life, all comers, setting. METHODS The REPLICA-EPIC18 study prospectively enrolled consecutive patients treated with IVL in 26 centers in Spain. An independent core laboratory performed the angiographic analysis and event adjudication. The primary effectiveness endpoint assessed procedural success (successful IVL delivery, final diameter stenosis <20%, and absence of in- hospital major adverse cardiovascular events [MACE]). The primary safety endpoint measured freedom from MACE at 30 days. A predefined substudy compared outcomes between acute coronary syndrome (ACS) and chronic coronary syndrome (CCS) patients. RESULTS A total of 426 patients (456 lesions) were included, 63% of the patients presenting with ACS. IVL delivery was successful in 99% of cases. Before IVL, 49% of lesions were considered undilatable. The primary effectiveness endpoint was achieved in 66% of patients, with similar rates among CCS patients (68%) and ACS patients (65%). Likewise, there were no significant differences in angiographic success after IVL between CCS and ACS patients. The rate of MACE at 30 days (primary safety endpoint) was 3% (1% in CCS and 5% in ACS patients [P = 0.073]). CONCLUSIONS Coronary IVL proved to be a feasible and safe procedure in a real-life setting, effectively facilitating stent implantation in severely calcified lesions. Patients with ACS on admission showed similar angiographic success rates but showed a trend toward higher 30-day MACE compared with patients with CCS. (REPLICA-EPIC18 study [Registry of Coronary Lithotripsy in Spain]; NCT04298307) (c) 2024 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Revisiting the epidemiology of bloodstream infections and healthcare-associated episodes: results from a multicentre prospective cohort in Spain (PRO-BAC Study)
PROBAC REIPI/GEIH-SEIMC/SAEI Group.The epidemiology of bloodstream infections (BSIs) is dynamic as it depends on microbiological, host and healthcare system factors. The aim of this study was to update the information regarding the epidemiology of BSIs in Spain considering the type of acquisition. An observational, prospective cohort study in 26 Spanish hospitals from October 2016 through March 2017 including all episodes of BSI in adults was performed. Bivariate analyses stratified by type of acquisition were performed. Multivariate analyses were performed by logistic regression. Overall, 6345 BSI episodes were included; 2510 (39.8%) were community-acquired (CA), 1661 (26.3%) were healthcare-associated (HCA) and 2056 (32.6%) hospital-acquired (HA). The 30-day mortality rates were 11.6%, 19.5% and 22.0%, respectively. The median age of patients was 71 years (interquartile range 60–81 years) and 3656 (58.3%; 95% confidence interval 57.1–59.6%) occurred in males. The proportions according to patient sex varied according to age strata. Escherichia coli (43.8%), Klebsiella spp. (8.9%), Staphylococcus aureus (8.9%) and coagulase-negative staphylococci (7.4%) were the most frequent pathogens. Multivariate analyses confirmed important differences between CA and HCA episodes, but also between HCA and HA episodes, in demographics, underlying conditions and aetiology. In conclusion, we have updated the epidemiological information regarding patients’ profiles, underlying conditions, frequency of acquisition types and aetiological agents of BSI in Spain. HCA is confirmed as a distinct type of acquisition.This work was financed by grants from Plan Nacional de I+D+i 2013–2016, Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades [PI16/01432] and the Spanish Network for Research in Infectious Diseases (REIPI) [RD16/0016/0001; RD16/0016/0008], co‐financed by the European Development Regional Fund ‘A way to achieve Europe’, Operative program Intelligent Growth 2014–2020
- …