Studying the metal-ligand monoligation of alkali/alkaline earth metals (AMs) in solution represents a significant challenge due to the low stabilization of their complexes and the absence of an ...effective strategy to identify this type of weak binding. Herein, we show that the modulation of the intramolecular charge-transfer (ICT) in an excited ambidentate organic fluorophore is a convenient strategy to characterize the binding chemistry of AM cations in solution through simple steady-state fluorescence and fluorescence lifetime measurements. The key points of the fluorophore as a metal-binding probe were the location of diverse coordination functionalities with different binding abilities (ionic-, pseudo-covalent- and non-covalent-probes) along the donor-acceptor (D-A) chain and the occurrence of an intramolecular charge-transfer (ICT) mechanism upon excitation. The binding of these functionalities with AM-cations generated selective and specific fluorescence responses, which were quantifiable and allowed us to recognize the primary, secondary and tertiary interactions for all the AM cations in the solution. The relative binding affinities for each one of the functionalities with AM cations was estimated, and a general and consistent perspective of the binding of AMs as a function of their location in the Periodic Table, hardness property and ionic radius was established. The binding preferences of the AM cations were supported by DFT calculations. Our strategy allowed us to validate the binding dynamics of AMs in solution for three types of key ligations, which opens a new perspective to recognize weak intermolecular interactions derived from acidic species and rationally design selective AM-cation probes using an ICT-based ambidentate organic fluorophore.
Herein, we explored the binding chemistry in solution of alkaline and alkaline earth cations as a function of hardness, ionic radius and location in the Periodic Table of Elements, modulating the ICT of an excited ambidentate fluorophore.
Metal–organic frameworks (MOFs) are a rapidly growing class of materials that offer great promise in various applications. However, the synthesis remains challenging: for example, a range of crystal ...structures can often be accessed from the same building blocks, which complicates the phase selectivity. Likewise, the high sensitivity to slight changes in synthesis conditions may cause reproducibility issues. This is crucial, as it hampers the research and commercialization of affected MOFs. Here, it presents the first‐ever interlaboratory study of the synthetic reproducibility of two Zr–porphyrin MOFs, PCN‐222 and PCN‐224, to investigate the scope of this problem. For PCN‐222, only one sample out of ten was phase pure and of the correct symmetry, while for PCN‐224, three are phase pure, although none of these show the spatial linker order characteristic of PCN‐224. Instead, these samples resemble dPCN‐224 (disordered PCN‐224), which has recently been reported. The variability in thermal behavior, defect content, and surface area of the synthesised samples are also studied. The results have important ramifications for field of metal–organic frameworks and their crystallization, by highlighting the synthetic challenges associated with a multi‐variable synthesis space and flat energy landscapes characteristic of MOFs.
It performed an interlaboratory study of the synthesis of the metal‐organic frameworks (MOFs) PCN‐222 and PCN‐224. Ten participants independently synthesized the two MOFs and the products are analyzed, primarily by X‐ray diffraction. The success rates are low (one‐three samples corresponding to a pure sample of the correct phase), thus highlighting the problems with irreproducibility in MOF synthesis.
Biotemplating is a powerful approach for manufacturing small‐scale devices. Here, the assembly of metal–organic framework (MOF) nanocrystals onto biotemplated magnetic helical structures on the ...cyanobacterium Spirulina platensis is reported. It is demonstrated that the authors’ approach is universal and can be used to equip biotemplated structures with different functional MOF systems. The successful assembly of MOF nanocrystals on magnetically coated helical biotemplates is achieved by decorating the magnetic surface with gelatin, a naturally occurring macromolecule with synthon moieties that allows anchoring of the MOF nanocrystals via electrostatic interactions. Furthermore, as gelatin is a thermally responsive material, it can serve to free the magnetic biotemplates from the MOF nanocrystal cargoes. As such, the systems can be used as highly integrated magnetically driven microrobots with multiple functionalities. To this end, the potential of these composite helical architectures is demonstrated as MOF‐based small‐scale robots with applications in biomedicine and environmental remediation.
The gelatin‐mediated integration of metal–organic framework (MOF) nanocrystals onto biotemplated magnetic helical structures formed on Spirulina platensis is reported. The authors’ approach is universal and can be used to equip biotemplated architectures with different functional MOF systems. The potential of these composite helical architectures as MOF‐based microrobots with applications in biomedicine and environmental remediation is demonstrated.
Purpose
The aim of the study was to compare the outcomes of patients with post‐COVID‐19 condition undergoing supervised therapeutic exercise intervention or following the self‐management WHO (World ...Health Organization) rehabilitation leaflet.
Methods
A randomized controlled trial was carried out that included 39 participants with post‐COVID‐19 condition who had a chronic symptomatic phase lasting >12 weeks. Comprehensive medical screening, patient‐reported symptoms, and cardiorespiratory fitness and muscular strength were assessed. Patients were randomly assigned to a tailored multicomponent exercise program based on concurrent training for 8 weeks (two supervised sessions per week comprised resistance training combined with aerobic training moderate intensity variable training, plus a third day of monitored light intensity continuous training), or to a control group which followed the WHO guidelines for rehabilitation after COVID‐19.
Results
After follow‐up, there were changes in physical outcomes in both groups, however, the magnitude of the change pre–post intervention favored the exercise group in cardiovascular and strength markers: VO2max +5.7%, sit‐to‐stand −22.7% and load‐velocity profiles in bench press +6.3%, and half squat +16.9%, (p < 0.05). In addition, exercise intervention resulted in a significantly better quality of life, less fatigue, less depression, and improved functional status, as well as in superior cardiovascular fitness and muscle strength compared to controls (p < 0.05). No adverse events were observed during the training sessions.
Conclusion
Compared to current WHO recommendations, a supervised, tailored concurrent training at low and moderate intensity for both resistance and endurance training is a more effective, safe, and well‐tolerated intervention in post‐COVID‐19 conditions.
A transition metal‐free, environment‐friendly and practical protocol was developed either for the reduction of nitroarenes or for the deoxygenation of N‐oxide containing heteroarenes. The reaction ...proceeded with the use of a non‐toxic and cheap feedstock as elemental sulfur in aqueous methanol under relatively mild conditions. Green chemistry credentials were widely favorable compared to traditional and industrial protocols with good E‐factors and a low production of waste. The strategy allowed the efficient reduction of a large variety of substituted‐nitroarenes including various o‐nitroanilines as well as selective reduction of various poly‐nitroarenes in excellent yields with a broad substrate scope. The protocol was successfully extended to the deoxygenation of some N‐oxide containing heteroarenes, like benzofuroxans, phenazine N,N'‐dioxides, pyridine N‐oxides, 2H‐indazole N1‐oxides, quinoxaline N1,N4‐dioxides and benzodimidazole N1,N3‐dioxides. A gram‐scale example for the synthesis of luminol, in green conditions, was reported. A solid mechanism of reaction was proposed from experimental evidences.
A facile and convenient protocol for the reduction of nitro‐arenes and deoxygenation of heteroarenes N‐oxides under transition metal and additive free conditions has been developed. The strategy allows the selective reduction of poly‐nitroarenes as well as the efficient deoxygetaion of a variety of N‐oxides containing heteroarenes including benzofuroxanes and phenzines with a broad substrate scope through a simply mixing operation.
Double-blind peer review is considered a pillar of academic research because it is perceived to ensure a fair, unbiased, and fact-centered scientific discussion. Yet, experienced researchers can ...often correctly guess from which research group an anonymous submission originates, biasing the peer-review process. In this work, we present a transformer-based, neural-network architecture that only uses the text content and the author names in the bibliography to attribute an anonymous manuscript to an author. To train and evaluate our method, we created the largest authorship-identification dataset to date. It leverages all research papers publicly available on arXiv amounting to over 2 million manuscripts. In arXiv-subsets with up to 2,000 different authors, our method achieves an unprecedented authorship attribution accuracy, where up to 73% of papers are attributed correctly. We present a scaling analysis to highlight the applicability of the proposed method to even larger datasets when sufficient compute capabilities are more widely available to the academic community. Furthermore, we analyze the attribution accuracy in settings where the goal is to identify all authors of an anonymous manuscript. Thanks to our method, we are not only able to predict the author of an anonymous work but we also provide empirical evidence of the key aspects that make a paper attributable. We have open-sourced the necessary tools to reproduce our experiments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The chemistry of metal–organic frameworks (MOFs) relies on the controlled linking of organic molecules and inorganic secondary building units to assemble an unlimited number of reticular frameworks. ...However, the design of porous solids with chemical stability still remains limited to carboxylate or azolate groups. There is a timely opportunity to develop new synthetic platforms that make use of unexplored metal binding groups to produce metal–linker joints with hydrolytic stability. Living organisms use siderophores (iron carriers in Greek) to effectively assimilate iron in soluble form. These compounds make use of hard oxo donors as hydroxamate or catecholate groups to coordinate metal Lewis acids such as iron, aluminum, or titanium to form metal complexes very stable in water. Inspired by the chemistry of these microorganisms, we report the first hydroxamate MOF prepared by direct synthesis. MUV-11 (MUV = materials of Universidad de Valencia) is a crystalline, porous material (close to 800 m2·g–1) that combines photoactivity with good chemical stability in acid conditions. By using a high-throughput approach, we also demonstrate that this new chemistry is compatible with the formation of single-crystalline phases for multiple titanium salts, thus expanding the scope of accessible precursors. Titanium frameworks are regarded as promising materials for photocatalytic applications. Our photoelectrochemical and catalytic tests suggest important differences for MUV-11. Compared to other Ti-MOFs, changes in the photoelectrochemical and photocatalytic activity have been rationalized with computational modeling, revealing how the chemistry of siderophores can introduce changes to the electronic structure of the frontier orbitals, relevant to the photocatalytic activity of these solids.
Herein, recent developments for Selectfluor-mediated C–H functionalization of
N
-heteroarenes are described. This type of C–H bond activation is an attractive and competitive alternative to ...traditional methodologies, allowing the functionalization of a variety of chemical functions. In addition, Selectfluor is a more sustainable and economically accessible oxidant compared with expensive/toxic metals or hazardous peroxides. For a practical understanding, the current review classified systematically the reported strategies in four subsections as follows: (1) carbon–carbon formation, (2) carbon–nitrogen bond formation, (3) carbon–chalcogen bond, and (4) carbon–halogen bond formation. Mechanistic aspects and reaction conditions are fully discussed to provide an understanding of the aspects that govern C–H functionalization in
N
-heteroarenes mediated by Selectfluor.
Graphical Abstract
Malaria represents a significant health issue, and novel effective drugs are needed to address parasite resistance that has emerged to the current drug arsenal. The most popular antimalarial drugs ...are focused on the 7-chloro-4-aminoquinoline e.g., chloroquine (CQ), amodiaquine (AQ), isoquine (IQ), and tebuquine (TBQ), artemisinin, and atovaquone systems. Recently, endochin has been used as a platform to design a variety of novel potent and safe antimalarial agents named endochin-like quinolones (ELQs). Also, antimalarial quinolones have been constructed from other quinolones drugs such as ICI-56780 and floxacrine. Trifluoromethyl substitution has provided a significant increase in the antimalarial response of many of the designed ELQs against
Plasmodium
-resistant strains and for in vivo models. In particular, attachment of a substituted trifluoromethoxy (or trifluoromethyl in some cases) biaryl side chain at 2-, 3-, 4-, or 6-position of the quinolone core has shown to be crucially important to generate selective and potent novel ELQs. Furthermore, 6-chloro and 7-methoxy moieties on the quinolone core have been identified as essential pharmacophores when the trifluoromethoxy biaryl side chain is placed at 2- or 3-position of the quinolone core. Methyl or ethyl ester attached at 3-position is essential when the trifluoromethoxy aryl side chain is attached at 6- or 7-position of the quinolone core. Some promising ELQs are currently under clinical trials, representing an excellent platform for the design of new potent, selective, effective, and safe antimalarial drugs against emergent resistance malarial models.
The autonomic nervous system (ANS) functioning has been proposed as a relevant method to characterize the therapeutic needs of intimate partner violence (IPV) perpetrators. Nevertheless, research has ...neglected the influence of the ANS on socio‐affective functions in this population. The aim of the present study was to analyze the psychophysiological activity of IPV perpetrators (n = 52) compared to controls (n = 46) following an empathic induction task, performed through negative emotion‐eliciting videos. We employed two general ANS markers (heart rate HR and respiratory rate RR), two sympathetic‐related indexes (pre‐ejection period PEP and skin conductance level SCL) and a parasympathetic biomarker (respiratory sinus arrhythmia RSA). Additionally, we explored the impact of psychophysiological activity on prosocial behavior using Hare's donation procedure. Compared to controls, IPV perpetrators reported lower HR and SCL following the task, as well as longer PEP, suggesting an attenuated sympathetic response to others' distress. No differences in the RSA response pattern were found, however, IPV perpetrators displayed lower overall RSA levels throughout the protocol, indicative of reduced parasympathetic activity. Besides, while no differences in prosocial performance were observed, greater sympathetic responses and overall parasympathetic activity predicted increased donations across the sample. Thus, a high sympathetic and parasympathetic activity might influence the occurrence of prosocial behavior. The present study provides further evidence supporting that IPV perpetrators cope differently with others' negative emotions. In line with this biopsychosocial perspective, insights are gained on the emotional processing of IPV perpetrators which, in turn, could contribute to improve IPV psychotherapeutic programs.
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