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The kinetics of gelation in the Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP) of styrene, using a bifunctional initiator and no crosslinking agents are investigated. By applying the method of moments, we develop a system of differential equations that accounts for the formation of polymer rings. The kinetic rate constants of this model are optimized on the experimentally determined kinetics, varying the reaction temperature and ethanol fraction. Subsequently, we explore how variations in the amounts of catalyst, initiator, and reducing agents affect the simulated equilibria of ARGET ATRP, the emergence of gelation, and the swelling properties of the resulting networks. These findings suggest that favoring ring formation enhances the gelation phenomenon, supporting the hypothesis that the networks formed under the reported reaction conditions are olympic gels., (© 2024 The Author(s). Macromolecular Rapid Communications published by Wiley‐VCH GmbH.)

Over the past two decades, the chirality-induced spin selectivity (CISS) effect was reported in several experiments disclosing a unique connection between chirality and electron spin. Recent theoretical works highlighted time-resolved Electron Paramagnetic Resonance (trEPR) as a powerful tool to directly detect the spin polarization resulting from CISS. Here, we report a first attempt to detect CISS at the molecular level by linking the pyrene electron donor to the fullerene acceptor with chiral peptide bridges of different length and electric dipole moment. The dyads are investigated by an array of techniques, including cyclic voltammetry, steady-state and transient optical spectroscopies, and trEPR. Despite the promising energy alignment of the electronic levels, our multi-technique analysis reveals no evidence of electron transfer (ET), highlighting the challenges of spectroscopic detection of CISS. However, the analysis allows the formulation of guidelines for the design of chiral organic model systems suitable to directly probe CISS-polarized ET., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Enantio-discrimination and spin-dependent electrochemistry (SDE), as a manifestation of the chirality-induced spin selectivity (CISS) effect, are important phenomena that can be probed by "chiral" electrochemistry. Here, we prepared chiralized surfaces of gold and nickel, to serve as working electrodes, through effective chemisorption of enantiopure dimethyl-bis(ethylenedithio)-tetrathiafulvalene (DM-BEDT-TTF) 1, tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) 2, and their capped silver nanoparticle (AgNPs) aggregate by simple incubation of the metallic substrates. The effective chemisorption was checked by means of ultrahigh vacuum x-ray photoelectron spectroscopy (XPS) and by electro-desorption experiments, i.e., cyclic voltammetry (CV) scans showing a first electro-desorption peak at about -1.0 V. The Au|1 and Au|2 chiral electrodes were successfully used in CV experiments exploiting chiral redox probes. Finally, the hybrid interfaces Ni|enantiopure 1 or 2|AgNPs served as working electrodes in SDE experiments. In particular, the hybrid chiral interfaces Ni|(R)-2|AgNPs and Ni|(S)-2|AgNPs exhibited a significant spin-filtering ability, as a manifestation of the CISS effect, with average spin polarization values of 15%., (© 2023 Author(s). Published under an exclusive license by AIP Publishing.)

The chirality-induced spin selectivity (CISS) effect allows thin-film layers of chiral conjugated molecules to function as spin filters at ambient temperature. Through solvent-modulated dropcasting of chiral l- and d-perylene diimide (PDI) monomeric building blocks, two types of aggregate morphologies, nanofibers and nanodonuts, may be realized. Spin-diode behavior is evidenced in the nanodonut structures. Stacked PDI units, which form the conjugated core of these nanostructures, dominate the nanodonut-Au electrode contact; in contrast, the AFM tip contacts largely the high-resistance solubilizing alkyl chains of the chiral monomers that form these nanodonuts. Current-voltage responses of the nanodonuts, measured by magnetic conductive AFM (mC-AFM), demonstrate substantial spin polarizations as well as spin current rectification ratios (>10) that exceed the magnitudes of those determined to date for other chiral nanoscale systems. These results underscore the potential for chiral nanostructures, featuring asymmetric molecular junctions, to enable CISS-based nanoscale spin current rectifiers.

We describe the spin polarization-induced chirogenic electropolymerization of achiral 2-vinylpyridine, which forms a layer of enantioenhanced isotactic polymer on the electrode. The product formed is enantioenriched in asymmetric carbon polymer. To confirm the chirality of the polymer film formed on the electrode, we also measured its electron spin polarization properties as a function of its thickness. Two methods were used: First, spin polarization was measured by applying magnetic contact atomic force microscopy, and second, magnetoresistance was assessed in a sandwich-like four-point contact structure. We observed high spin-selective electron transmission, even for a layer thickness of 120 nm. A correlation exists between the change in the circular dichroism signal and the change in the spin polarization, as a function of thickness. The spin-filtering efficiency increases with temperature.

Breast cancer is the most common tumor in middle-aged and older women. In 2003, the European Parliament recommended to Member States that all women with breast cancer should be treated by a multidisciplinary team and that a network of certified breast centers be organized (the centers have been called Breast Units (BUs)). With the present study, we aim to explore the impact of the introduction of the BU organizational model in the Liguria region, Italy, through different outcome indicators. An explorative retrospective analysis was conducted through the period from 2013 to 2019 to assess the impact of the introduction of the BU model in our region. We identified two periods: before (2014-2015) and after (2017-2018) the introduction of this organizational model to assess its value impact through the definition of six measurable outcome indicators. Length of hospitalization, repeated specialist outpatient diagnostic procedures and the rate of subjects who started radiotherapy treatment within 60 days improved after the introduction of BUs. The passive health migration rate only improved significantly for one local health unit (LHU), while reintervention and diagnosis-surgery time did not show any enhancement after the introduction of the BU model. The BU model seems to provide an increase in several aspects of the healthcare offered to breast cancer patients in Liguria, specifically in those areas where a shared guideline could assist healthcare workers. Future research, such as pilot studies, are needed to assess the impact of the introduction of the BU model in our reality.

Controlled reduction of oxygen is important for developing clean energy technologies, such as fuel cells, and is vital to the existence of aerobic organisms. The process starts with oxygen in a triplet ground state and ends with products that are all in singlet states. Hence, spin constraints in the oxygen reduction must be considered. Here, we show that the electron transfer efficiency from chiral electrodes to oxygen (oxygen reduction reaction) is enhanced over that from achiral electrodes. We demonstrate lower overpotentials and higher current densities for chiral catalysts versus achiral ones. This finding holds even for electrodes composed of heavy metals with large spin-orbit coupling. The effect results from the spin selectivity conferred on the electron current by the chiral assemblies, the chiral-induced spin selectivity effect.

A critical spintronics challenge is to develop molecular wires that render efficiently spin-polarized currents. Interplanar torsional twisting, driven by chiral binucleating ligands in highly conjugated molecular wires, gives rise to large near-infrared rotational strengths. The large scalar product of the electric and magnetic dipole transition moments ([Formula: see text]), which are evident in the low-energy absorptive manifolds of these wires, makes possible enhanced chirality-induced spin selectivity-derived spin polarization. Magnetic-conductive atomic force microscopy experiments and spin-Hall devices demonstrate that these designs point the way to achieve high spin selectivity and large-magnitude spin currents in chiral materials., Competing Interests: The authors declare no competing interest., (Copyright © 2022 the Author(s). Published by PNAS.)

Background: We conducted a population-based cohort study to estimate mortality before, during and after the COVID-19 peak and to compare mortality in 2020 with rates reported in previous years, with a view to helping decision makers to apply containment measures for high-risk groups., Methods: All deaths were collected between 2015 and 2020 from municipal registry database. In 2020, weeks 1-26 were stratified in three periods: before, during and after the COVID mortality peak. The Poisson Generalized Linear regression Model showed the "harvesting effect". Three logistic regressions for 8 dependent variables (age and comorbidities) and a t-test of differences described all-cause mortality risk factors in 2019 and 2020 and differences between COVID and non-COVID patients., Results: A total of 47,876 deaths were collected. All-cause deaths increased by 38.5% during the COVID peak and decreased by 18% during the post-peak period in comparison with the average registered during the control period (2015-19), with significant mortality displacement in 2020. Except for chronic renal injuries in subjects aged 45-64 years, diabetes and chronic cardiovascular diseases in those aged 65-84 years, and neuropathies in those aged > 84 years, the weight of comorbidities in deaths was similar or lower in COVID subjects than in non-COVID subjects., Discussions: Surprisingly, the weight of comorbidities in death, compared to weight in non-COVID subjects allows you to highlight some surprising results such as COPD, IBD and Cancer. The excess mortality that we observed in the entire period were modest in comparison with initial estimates during the peak, owing to the mild influenza season and the harvesting effect starting from the second half of May., Competing Interests: Conflict of interest statement The authors declare no conflict of interest., (©2021 Pacini Editore SRL, Pisa, Italy.)

Despite the availability of vaccines against Streptococcus pneumoniae , the global incidence and economic cost of pneumococcal disease (PD) among adults is still high. This retrospective cohort analysis estimated the cost of emergency department (ED) visits/hospitalizations associated with non-invasive pneumonia and invasive pneumococcal disease among individuals ≥15 years of age in the Liguria region of Italy during 2012-2018. Data from the Liguria Region Administrative Health Databases and the Ligurian Chronic Condition Data Warehouse were used, including hospital admission date, length of stay, discharge date, outpatient visits, and laboratory/imaging procedures. A ≥30-day gap between two events defined a new episode, and patients with ≥1 ED or inpatient claim for PD were identified. The total mean annual number of hospitalizations for PD was 13,450, costing ~€49 million per year. Pneumonia accounted for the majority of hospitalization costs. The median annual cost of hospitalization for all-cause pneumonia was €38,416,440 (per-capita cost: €26.78) and was €30,353,928 (per-capita cost: €20.88) for pneumococcal and unspecified pneumonia. The total number and associated costs of ED visits/hospitalizations generally increased over the study period. PD still incurs high economic costs in adults in the Liguria region of Italy.

It is established that electron transmission through chiral molecules depends on the electron's spin. This phenomenon, termed the chiral-induced spin selectivity (CISS), effect has been observed in chiral molecules, supramolecular structures, polymers, and metal-organic films. Which spin is preferred in the transmission depends on the handedness of the system and the tunneling direction of the electrons. Molecular motors based on overcrowded alkenes show multiple inversions of helical chirality under light irradiation and thermal relaxation. The authors found here multistate switching of spin selectivity in electron transfer through first generation molecular motors based on the four accessible distinct helical configurations, measured by magnetic-conductive atomic force microscopy. It is shown that the helical state dictates the molecular organization on the surface. The efficient spin polarization observed in the photostationary state of the right-handed motor coupled with the modulation of spin selectivity through the controlled sequence of helical states, opens opportunities to tune spin selectivity on-demand with high spatio-temporal precision. An energetic analysis correlates the spin injection barrier with the extent of spin polarization., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

The steady-state charge and spin transfer yields were measured for three different Ru-modified azurin derivatives in protein films on silver electrodes. While the charge-transfer yields exhibit weak temperature dependences, consistent with operation of a near activation-less mechanism, the spin selectivity of the electron transfer improves as temperature increases. This enhancement of spin selectivity with temperature is explained by a vibrationally induced spin exchange interaction between the Cu(II) and its chiral ligands. These results indicate that distinct mechanisms control charge and spin transfer within proteins. As with electron charge transfer, proteins deliver polarized electron spins with a yield that depends on the protein's structure. This finding suggests a new role for protein structure in biochemical redox processes., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Monolayers of chiral molecules can preferentially transmit electrons with a specific spin orientation, introducing chiral molecules as efficient spin filters. This phenomenon is established as chirality-induced spin selectivity (CISS) and was demonstrated directly for the first time in self-assembled monolayers (SAMs) of double-stranded DNA (dsDNA) 1 . Here, we discuss SAMs of double-stranded peptide nucleic acid (dsPNA) as a system which allows for systematic investigations of the influence of various molecular properties on CISS. In photoemission studies, SAMs of chiral, γ-modified PNA show significant spin filtering of up to P = (24.4 ± 4.3)% spin polarization. The polarization values found in PNA lacking chiral monomers are considerably lower at about P = 12%. The results confirm that the preferred spin orientation is directly linked to the molecular handedness and indicate that the spin filtering capacity of the dsPNA helices might be enhanced by introduction of chiral centers in the constituting peptide monomers., (© 2021 The Authors. Chirality published by Wiley Periodicals LLC.)

Squaraine dyes are well known for their strong absorption in the visible regime. Reports on chiral squaraine dyes are, however, scarce. To address this gap, we here report two novel chiral squaraine dyes and their achiral counterparts. The presented dyes are aggregated in solution and in thin films. A detailed chiroptical study shows that thin films formed by co-assembling the chiral dye with its achiral counterpart exhibit exceptional photophysical properties. The circular dichroism (CD) of the co-assembled structures reaches a maximum when just 25 % of the chiral dye are present in the mixture. The solid structures with the highest relative CD effect are achieved when the chiral dye is used solely as a director, rather than the structural component. The chiroptical data are further supported by selected spin-filtering measurements using mc-AFM. These findings provide a promising platform for investigating the relationship between the dissymmetry of a supramolecular structure and emerging material properties rather than a comparison between a chiral molecular structure and an achiral counterpart., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

The spin-spin interactions between chiral molecules and ferromagnetic metals were found to be strongly affected by the chiral induced spin selectivity effect. Previous works unraveled two complementary phenomena: magnetization reorientation of ferromagnetic thin film upon adsorption of chiral molecules and different interaction rate of opposite enantiomers with a magnetic substrate. These phenomena were all observed when the easy axis of the ferromagnet was out of plane. In this work, the effects of the ferromagnetic easy axis direction, on both the chiral molecular monolayer tilt angle and the magnetization reorientation of the magnetic substrate, are studied using magnetic force microscopy. We have also studied the effect of an applied external magnetic field during the adsorption process. Our results show a clear correlation between the ferromagnetic layer easy axis direction and the tilt angle of the bonded molecules. This tilt angle was found to be larger for an in plane easy axis as compared to an out of plane easy axis. Adsorption under external magnetic field shows that magnetization reorientation occurs also after the adsorption event. These findings show that the interaction between chiral molecules and ferromagnetic layers stabilizes the magnetic reorientation, even after the adsorption, and strongly depends on the anisotropy of the magnetic substrate. This unique behavior is important for developing enantiomer separation techniques using magnetic substrates.

The electronic properties of conducting polymers are influenced by their micro- and macrostructural orders, which can be tailored by substituent modification. However, while the effect of substituents on conducting polymers is extensively investigated, chiral substituents are far less studied. Furthermore, many chiral conducting polymers have regioirregular structures, which result in polymer films with inferior properties. In this work, we apply electronic circular dichroism (ECD) spectroscopy to study the morphological changes to the chiral polymers under different polymerization conditions. For this purpose, we investigated 3,4-ethylenedioxythiophene (EDOT) derivatives having two stereogenic centers on each monomer and bearing methyl or phenyl side groups (dimethyl-EDOT and diphenyl-EDOT, respectively). Polymerizing the enantiomerically pure monomers produces regioregular and stereoregular dimethyl-PEDOT and diphenyl-PEDOT, respectively. The effect of the electrolyte and solvent on polymer film morphology was studied using scanning electron microscopy (SEM) and ECD, showing a correlation between the polymer's morphology and the chiroptical properties of its films. We found that, for diphenyl-PEDOT, the combination of perchlorate anion electrolyte and acetonitrile solvent resulted in a unique morphology characterized by significant intermolecular interactions. These interactions were clearly observable in the ECD spectra in the form of exciton couplings, whose presence was supported by TD-DFT calculations. A small enantiomeric excess was sufficient to induce very intense ECD signals, demonstrating chiral amplification in electropolymerized films., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

Essential aspects of the chiral induced spin selectivity (CISS) effect and their implications for spin-controlled chemistry and asymmetric electrochemical reactions are described. The generation of oxygen through electrolysis is discussed as an example in which chirality-based spin-filtering and spin selection rules can be used to improve the reaction's efficiency and selectivity. Next the discussion shifts to illustrate how the spin selectivity of chiral molecules (CISS properties) allows one to use the electron spin as a chiral bias for inducing asymmetric reactions and promoting enantiospecific processes. Two enantioselective electrochemical reactions that have used polarized electron spins as a chiral reagent are described; enantioselective electroreduction to resolve an enantiomer from a racemic mixture and an oxidative electropolymerization to generate a chiral polymer from achiral monomers. A complementary approach that has used spin-polarized, but otherwise achiral, molecular films to enantiospecifically associate with one enantiomer from a racemic mixture is also discussed. Each of these reaction types use magnetized films to generate the spin polarized electrons and the enantiospecificity can be selected by choice of the magnetization direction, North pole versus South pole. Possible paths for future research in this area and its compatibility with existing methods based on chiral electrodes are discussed.

Aim: During the last decade a continuous increase in non-albicans species isolation has been observed with Candida parapsilosis being one of the leading species. Aim of this study was to describe the epidemiology of candidemia, particularly of C parapsilosis, its predictors and clinical outcome., Materials and Methods: Incidences of candidemia was evaluated analyzing data from both a prospective collection (2012-2016) and a retrospective one (2008-2011). Predictors and outcome were based only on the prospective phase. C parapsilosis potential clusters were analysed by randomly amplified polymorphic DNA (RAPD) technique., Results: 1240 episodes were identified. Incidences of candidemia increased from 1.97 episodes/10 000 patient-days in 2008 to 4.59/10 000 patient-days in 2016 (P < .001), mainly due to an increase of C parapsilosis (incidence rate ratio, IRR: 1.04, P < .001). 33.0% of C parapsilosis strains were resistant to fluconazole; no resistance to echinocandins was found. Independent predictors of C parapsilosis candidemia were time of infection (P = .007), previous use of echinocandins (P < .0001) and year in which the episode was registered (P < .0001). 30 days mortality was 32.4% for C parapsilosis, with a significant difference compared to C non-parapsilosis. Potential clonal C parapsilosis strains were detected by genetic analyses, showing RAPD profile A as the most represented (72.6% of isolates)., Discussion: C parapsilosis candidemia is an emerging issue in our center, possibly attributed to some extent to horizontal transmission of the pathogen, as confirmed by the analysis of isolates similarities. Further microbiological and epidemiological investigations are needed in order to identify the most effective measures to reduce the rate of this infection., (© 2020 Blackwell Verlag GmbH.)

Organic semiconductors and organic-inorganic hybrids are promising materials for spintronic-based memory devices. Recently, an alternative route to organic spintronic based on chiral-induced spin selectivity (CISS) is suggested. In the CISS effect, the chirality of the molecular system itself acts as a spin filter, thus avoiding the use of magnets for spin injection. Here, spin filtering in excess of 85% in helical π-conjugated materials based on supramolecular nanofibers at room temperature is reported. The high spin-filtering efficiency can even be observed in nanofibers assembled from mixtures of chiral and achiral molecules through chiral amplification effect. Furthermore and most excitingly, it is shown that both "up" and "down" orientations of filtered spins can be obtained in a single enantiopure system via the temperature-dependent helicity (P and M) inversion of supramolecular nanofibers. The findings showcase that materials based on helical noncovalently assembled systems are modular platforms with an emerging structure-property relationship for spintronic applications., (© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Chirality-induced spin selectivity is evidenced by exciting the spin resonance of radicals in an electrochemical cell where the working electrode is covered with a chiral self-assembled monolayer. Because the electron transfer to and from the paramagnetic radical is spin dependent, the electrochemical current changes at resonance. This electrically-detected magnetic resonance (EDMR) is monitored by a lock-in detection based on electrode voltage modulation, at a frequency that optimizes the sensitivity of the differential conductance to the electrode charge transfer process. The method is validated using p-doped GaAs electrodes in which the conduction band electrons are hyperpolarized by a well-known method of optical spin pumping with circularly polarized light. Gold electrodes covered with peptides consisting of 5 alanine groups (Al5) present a relative current change of up to 5 × 10-5 when the resonance condition is met, corresponding to a spin filtering efficiency between 6 and 19%.

We show that enantioselective reactions can be induced by the electron spin itself and that it is possible to replace a conventional enantiopure chemical reagent by spin-polarized electrons that provide the chiral bias for enantioselective reactions. Three examples of enantioselective chemistry resulting from electron-spin polarization are presented. One demonstrates the enantioselective association of a chiral molecule with an achiral self-assembled monolayer film that is spin-polarized, while the other two show that the chiral bias provided by the electron helicity can drive both reduction and oxidation in enantiospecific electrochemical reactions. In each case, the enantioselectivity does not result from enantiospecific interactions of the molecule with the ferromagnetic electrode but from the polarized spin that crosses the interface between the substrate and the molecule. Furthermore, the direction of the electron-spin polarization defines the handedness of the enantioselectivity. This work demonstrates a new mechanism for realizing enantioselective chemistry., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)