Comprehensive investigation of the triplet state electronic structure of free-base 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin by a combined advanced EPR and theoretical approach.

The nature of the photoexcited triplet state of free-base 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H2TPPS4-) has been investigated by advanced Electron Paramagnetic Resonance (EPR) techniques combined with quantum chemical calculations. The zero-field splitting (ZFS) parameters, D and E, the orientation of the transition dipole moment in the ZFS tensor frame, and the proton hyperfine couplings have been determined by magnetophotoselection-EPR and pulse electron-nuclear double resonance spectroscopy. Both time-resolved and pulse experiments exploit the electron spin polarization of the photoexcited triplet state. Comparison of the magnetic observables with computational results, including CASSCF calculations of the ZFS interaction tensor, provides an accurate picture of the triplet-state electronic structure. The theoretical investigation has been integrated with a systematic analysis on the parent free-base porphyrin molecule to assess the effect of the sulfonatophenyl substituents on the magnetic tensors. Additionally, the magnetophotoselection effects are discussed in terms of tautomerization in the excited singlet state of H2TPPS4-.

Distance measurements in peridinin-chlorophyll a-protein by light-induced PELDOR spectroscopy. Analysis of triplet state localization.

Triplet-triplet energy transfer from chlorophylls to carotenoids is the mechanism underlying the photoprotective role played by carotenoids in many light harvesting complexes, during photosynthesis. The peridinin-chlorophyll-a protein (PCP) is a water-soluble light harvesting protein of the dinoflagellate Amphidinium carterae, employing peridinin as the main carotenoid to fulfil this function. The dipolar coupling of the triplet state of peridinin, populated under light excitation in isolated PCP, to the MTSSL nitroxide, introduced in the protein by site-directed mutagenesis followed by spin labeling, has been measured by Pulse ELectron-electron DOuble Resonance (PELDOR) spectroscopy. The triplet-nitroxide distance derived by this kind of experiments, performed for the first time in a protein system, allowed the assignment of the triplet state to a specific peridinin molecule belonging to the pigment cluster. The analysis strongly suggests that this peridinin is the one in close contact with the water ligand to the chlorophyll a, thus supporting previous evidences based on ENDOR and time resolved-EPR.

Delocalized triplet state in porphyrin J-aggregates revealed by EPR spectroscopy.

In this work, the electronic structure of the triplet state of self-assembled J-aggregates of tetrakis(4-sulfonatophenyl)porphyrin (TPPS) has been characterized by means of time-resolved electron paramagnetic resonance spectroscopy. Several insights into the triplet properties of the aggregate have been gained through comparison with the corresponding monomeric unit in both free base and acidified forms. Molecular distortions in the monomeric acidified TPPS cause variation in its zero-field splitting parameters and a redirection of triplet spin sublevel activity. The aggregation process does not alter the mechanism of triplet state population compared to the acidified monomer but it is accompanied by a further reduction in the zero-field splitting parameter D, which is possibly indicative of the formation of a delocalized triplet state species. The detection of a long-lived spin-polarized radical species also proves polaron generation and movement to a trap site in the J-aggregates.

Light-Induced Porphyrin-Based Spectroscopic Ruler for Nanometer Distance Measurements.

We present a novel pulsed electron paramagnetic resonance (EPR) spectroscopic ruler to test the performance of a recently developed spin-labeling method based on the photoexcited triplet state (S=1). Four-pulse electron double resonance (PELDOR) experiments are carried out on a series of helical peptides, labeled at the N-terminal end with the porphyrin moiety, which can be excited to the triplet state, and with the nitroxide at various sequence positions, spanning distances in the range 1.8-8 nm. The PELDOR traces provide accurate distance measurements for all the ruler series, showing deep envelope modulations at frequencies varying in a progressive way according to the increasing distance between the spin labels. The upper limit is evaluated and found to be around 8 nm. The PELDOR-derived distances are in excellent agreement with theoretical predictions. We demonstrate that high sensitivity is acquired using the triplet state as a spin label by comparison with Cu(II)-porphyrin analogues. The new labeling approach has a high potential for measuring nanometer distances in more complex biological systems due to the properties of the porphyrin triplet state.

Structural Changes of a Doubly Spin-Labeled Chemically Driven Molecular Shuttle Probed by PELDOR Spectroscopy.

Gaining detailed information on the structural rearrangements associated with stimuli-induced molecular movements is of utmost importance for understanding the operation of molecular machines. Pulsed electron-electron double resonance (PELDOR) was employed to monitor the geometrical changes arising upon chemical switching of a [2]rotaxane that behaves as an acid-base-controlled molecular shuttle. To this aim, the rotaxane was endowed with stable nitroxide radical units in both the ring and axle components. The combination of PELDOR data and molecular dynamic calculations indicates that in the investigated rotaxane, the ring displacement along the axle, caused by the addition of a base, does not alter significantly the distance between the nitroxide labels, but it is accompanied by a profound change in the geometry adopted by the macrocycle.

Porphyrin triplet state as a potential spin label for nanometer distance measurements by PELDOR spectroscopy.

This work demonstrates, for the first time, the feasibility of applying pulsed electron-electron double resonance (PELDOR/DEER) to determine the interspin distance between a photoexcited porphyrin triplet state (S = 1) and a nitroxide spin label chemically incorporated into a small helical peptide. The PELDOR trace shows deep envelope modulation induced by electron-electron dipole interaction between the partners in the pair, providing an accurate distance measurement. This new labeling approach has a high potential for measuring nanometer distances in more complex biological systems due to the sensitivity acquired from the spin polarization of the photoexcited triplet state spectrum.

Becoming Sandwiched in Later Life: Consequences for Individuals' Well-Being and Variation Across Welfare Regimes.

OBJECTIVES: The experience of being sandwiched between support obligations towards both aging parents and adult offspring is likely to become more common and more relevant. We aim at assessing the effect of demographic and social sandwiching on the psychological health and subjective well-being of individuals experiencing these transitions, and to what extent, these effects vary across welfare regimes. METHODS: Data are from 63,585 individuals aged 50-75 participating in the Survey of Health, Ageing and Retirement in Europe (SHARE). We estimate within- and between-individual effects using hybrid regression models to predict depressive symptoms (EURO-D) and subjective well-being (control, autonomy, self-realization, and pleasure [CASP]). RESULTS: Among demographically sandwiched women, transitioning into social sandwiching and into supporting only parents was associated with a moderate but statistically significant increase in EURO-D and decline in CASP scores. The same association is not observed for male respondents. The pattern of variation among women living in countries characterized by different welfare regimes suggests that social sandwiching is less detrimental in Nordic regimes than in other welfare contexts. DISCUSSION: Results from the between-individuals part of the model indicate that there is a selection into social sandwiching of more healthy individuals into support roles. However, the within-individuals part of the model indicates that the transition into social sandwiching has a detrimental effect on women's (but not men's) psychological health and well-being. The explanations for this gendered effect of social sandwiching may be found in the "invisible" support provided by women and the gendered division of specific care tasks.

The [4Fe-4S]-cluster coordination of [FeFe]-hydrogenase maturation protein HydF as revealed by EPR and HYSCORE spectroscopies.

[FeFe] hydrogenases are key enzymes for bio(photo)production of molecular hydrogen, and several efforts are underway to understand how their complex active site is assembled. This site contains a [4Fe-4S]-2Fe cluster and three conserved maturation proteins are required for its biosynthesis. Among them, HydF has a double task of scaffold, in which the dinuclear iron precursor is chemically modified by the two other maturases, and carrier to transfer this unit to a hydrogenase containing a preformed [4Fe-4S]-cluster. This dual role is associated with the capability of HydF to bind and dissociate an iron-sulfur center, due to the presence of the conserved FeS-cluster binding sequence CxHx(46-53)HCxxC. The recently solved three-dimensional structure of HydF from Thermotoga neapolitana described the domain containing the three cysteines which are supposed to bind the FeS cluster, and identified the position of two conserved histidines which could provide the fourth iron ligand. The functional role of two of these cysteines in the activation of [FeFe]-hydrogenases has been confirmed by site-specific mutagenesis. On the other hand, the contribution of the three cysteines to the FeS cluster coordination sphere is still to be demonstrated. Furthermore, the potential role of the two histidines in [FeFe]-hydrogenase maturation has never been addressed, and their involvement as fourth ligand for the cluster coordination is controversial. In this work we combined site-specific mutagenesis with EPR (electron paramagnetic resonance) and HYSCORE (hyperfine sublevel correlation spectroscopy) to assign a role to these conserved residues, in both cluster coordination and hydrogenase maturation/activation, in HydF proteins from different microorganisms.

Grandparents, family solidarity and the division of housework: evidence from the Italian case.

As a consequence of recent socio-demographic trends and labour market transformations the role of grandparental support has become pivotal in individuals' and households' life courses. In Southern European countries the availability of grandparents affects young couples' labour market participation and fertility decisions. In the present paper, it is asked if the potential availability of social support from the older family generation is associated with more or less inequality in the division of unpaid housework in couples with minor children, in Italy. Using data from the 2016 Family and Social Subjects survey it is shown that while there is not a clear relation between intergenerational face-to-face contacts and the symmetry of the division of household labour, adult children and older (grand)parents coresidence is associated with a more gender-equal sharing of housework within couples, arguably because co-residing grandparents take on the execution of a number of household tasks. The observed effect is comparable to that of hiring a paid housekeeper and higher than hiring a babysitter. Thus, despite one may think that three-generation households are characterized by a culture of traditional norms, our findings indicate that they have a more gender-equal division of housework.

The Older Sandwich Generation Across European Welfare Regimes: Demographic and Social Considerations.

The lengthening of the amount of time adult children depend on their parents' support and rising longevity have pushed scholars to devote increasing attention to the phenomenon of older sandwich family generations. This brief report develops a descriptive portrait of the prevalence of being demographically and socially sandwiched in the population aged 50 or more years, in Europe. It is shown that the prevalence of social sandwiching is highly sensitive to the types of support utilized to operationalize the concept; also, differences between welfare and transfer regimes are significantly affected by different operationalizations. Next, the analyses highlight the dynamic nature of social sandwiching over the adult life cycle, and show that demographic events and the changing needs of older parents are the main drivers of moving in/out the status of socially sandwiched. Support to adult children is ubiquitous in all European societies. Among the pivot generation family solidarity prevails over competition, but children enjoy a strategic advantage when older parents are in good health.

Validation and Ecological Niche Investigation of a New Fungal Intraspecific Competitor as a Biocontrol Agent for the Sustainable Containment of Aflatoxins on Maize Fields.

Crop yield and plant products quality are directly or indirectly affected by climate alterations. Adverse climatic conditions often promote the occurrence of different abiotic stresses, which can reduce or enhance the susceptibility to pests or pathogens. Aflatoxin producing fungi, in particular, whose diffusion and deleterious consequences on cereals commodities have been demonstrated to highly depend on the temperature and humidity conditions that threaten increasingly larger areas. Biological methods using intraspecific competitors to prevent fungal development and/or toxin production at the pre-harvest level are particularly promising, even if their efficacy could be affected by the ecological interaction within the resident microbial population. A previously characterized Aspergillus flavus atoxigenic strain was applied in two maize fields to validate its effectiveness as a biocontrol agent against aflatoxin contamination. At one month post-application, at the harvest stage, its persistence within the A. flavus population colonizing the maize kernels in the treated area was assessed, and its efficacy was compared in vitro with a representation of the isolated atoxigenic population. Results proved that our fungal competitor contained the aflatoxin level on maize grains as successfully as a traditional chemical strategy, even if representing less than 30% of the atoxigenic strains re-isolated, and achieved the best performance (in terms of bio-competitive potential) concerning endogenous atoxigenic isolates.

The spreading of SARS-CoV-2: Interage contacts and networks degree distribution.

Notable cross-country differences exist in the diffusion of the Covid-19 and in its lethality. Contact patterns in populations, and in particular intergenerational contacts, have been argued to be responsible for the most vulnerable, the elderly, getting infected more often and thus driving up mortality in some context, like in the southern European one. This paper asks a simple question: is it between whom contacts occur that matters or is it simply how many contacts people have? Due to the high number of confounding factors, it is extremely difficult to empirically assess the impact of single network features separately. This is why we rely on a simulation exercise in which we counterfactually manipulate single aspects of countries' age distribution and network structures. We disentangle the contributions of the kind and of the number of contacts while holding constant the age structure. More precisely, we isolate the respective effects of inter-age contact patterns, degree distribution and clustering on the virus propagation across age groups. We use survey data on face-to-face contacts for Great Britain, Italy, and Germany, to reconstruct networks that mirror empirical contact patterns in these three countries. It turns out that the number of social contacts (degree distribution) largely accounts for the higher infection rates of the elderly in the Italian context, while differences in inter-age contacts patterns are only responsible for minor differences. This suggests that policies specifically targeting inter-age contacts would be little effective.

Does Children's Union Dissolution Hurt Elderly Parents? Linked Lives, Divorce and Mental Health in Europe.

Previous research has shown that parent's union dissolution has negative consequences for individuals' well-being, parent-child relationships and children's outcomes. However, less attention has been devoted to the effects in the opposite direction, i.e. how children's divorce affects parents' well-being. We adopted a cross-country, longitudinal and multigenerational perspective to analyse whether children's marital break-up is associated with changes in parents' depressive symptoms. Using data from 17 countries and 5 waves of the Survey of Health, Ageing and Retirement in Europe (2004-2015), fixed effect linear regression models were estimated to account for time-constant social selection processes into divorce/separation. The results show that across European contexts parents' depressive symptoms increased as one of their children divorced. Furthermore, we found that parents living in more traditional societies, such as Southern European ones, experienced higher increases in depression symptoms when a child divorced than those living in Nordic countries. Overall, the findings provide new evidence in support of both the notion of "linked lives" and a normative perspective of family life course events.

Secondhand smoke exposure in hospitality venues in Europe.

BACKGROUND: Although in the last few years some European countries have implemented smoking bans in hospitality venues, the levels of secondhand smoke (SHS) in this occupational sector could still be extremely high in most countries. OBJECTIVE: The aim of this study was to assess exposure to SHS in hospitality venues in 10 European cities. METHODS: We included 167 hospitality venues (58 discotheques and pubs, 82 restaurants and cafeterias, and 27 fast-food restaurants) in this cross-sectional study. We carried out fieldwork in 10 European cities: Vienna (Austria), Paris (France), Athens (Greece), Florence and Belluno (Italy), Galway (Ireland), Barcelona (Spain), Warsaw and Lublin (Poland), and Bratislava (Slovak Republic). We measured vapor-phase nicotine as an SHS marker. RESULTS: We analyzed 504 samples and found nicotine in most samples (97.4%). We found the highest median concentrations in discos/pubs [32.99 microg/m(3); interquartile range (IQR), 8.06-66.84 microg/m(3)] and lower median concentrations in restaurants/cafeterias (2.09 microg/m(3); IQR, 0.49-6.73 microg/m(3)) and fast-food restaurants (0.31 microg/m(3); IQR, 0.11-1.30 microg/m(3)) (p < 0.05). We found differences of exposure between countries that may be related to their smoking regulations. Where we sampled smoking and nonsmoking areas, nicotine concentrations were significantly lower in nonsmoking areas. CONCLUSIONS: Hospitality venues from European cities without smoking regulations have very high levels of SHS exposure. Monitoring of SHS on a regular basis as well as a total smoking ban in hospitality sector would be needed.

Prevalence of second-hand smoke exposure after introduction of the Italian smoking ban: the Florence and Belluno survey.

AIMS AND BACKGROUND: A law banning smoking in enclosed public places was implemented in Italy on January 10, 2005. The aim of this paper is to present a cross-sectional survey on two representative samples of non-smokers of two Italian towns (Florence and Belluno), conducted one year after the introduction of the ban, in order to assess prevalence of second-hand smoke exposure, to record the attitudes towards the ban, and the perception about its compliance in a representative sample of non-smokers. METHODS: Computer-assisted telephone interviews were carried out in March 2006, from a random sample of households from telephone registries. Respondents were 402 non-smokers from Belluno and 1,073 from Florence. RESULTS: About 12% of Florentines and 7% of Belluno respondents were exposed at home; 39% and 19%, respectively, at work; 10% and 5% in hospitality venues; 20% and 10% in cars. The smoke-free law was almost universally supported (about 98%) even if a smaller proportion of people (about 90%) had the perception that the ban was observed. CONCLUSIONS: Second-hand smoke exposure at home and in hospitality premises has dropped to < or = 10%, whereas exposure at work remained higher. These results suggest the need for more controls in workplaces other than hospitality venues.

Grandparenting after parental divorce: The association between non-resident parent-child meetings and grandparenting in Italy.

Previous studies have shown that parental divorce has negative consequences on parent-child relationships and that these effects extend to relations between grandchildren and their grandparents. After parental divorce, grandchildren have less intense and lower quality relations with their grandparents. Some studies suggest that this negative association between union dissolution in the middle generation and grandparent-grandchild relations is explained by the post-divorce residential arrangements and, to a lesser extent, by the gatekeeping role exercised by the resident parent. The role of the frequency of meetings between the non-resident parent and his/her children, however, has been often overlooked in this literature. Using cross-sectional data from the Italian Family and Social Subject Survey, our study explores the extent to which frequent meetings between non-resident separated or divorced parents and their children below age 14 are correlated with grandparent involvement in looking after their grandchildren. The results show that young children who have very frequent meetings with their non-resident parents are more likely to receive care from their grandparents than are those who meet the non-resident parents once a week or less frequently.

Family transfers and long-term care: An analysis of the WHO Study on global AGEing and adult health (SAGE).

BACKGROUND: Populations globally are ageing, resulting in increased need for long-term care. Where social welfare systems are insufficient, these costs may fall to other family members. We set out to estimate the association between long-term care needs and family transfers in selected low- and middle- income countries. METHODS: We used data from the World Health Organization's Study on global AGEing and adult health (SAGE). Using regression, we analysed the relationship between long-term care needs in older households and i) odds of receiving net positive transfers from family outside the household and ii) the amount of transfer received, controlling for relevant socio-demographic characteristics. RESULTS: The proportion of household members requiring long-term care was significantly associated with receiving net positive transfers in China (OR: 1.76; p = 0.023), Ghana (OR: 2.79; p = 0.073), Russia (OR: 3.50; p < 0.001). There was a statistically significant association with amount of transfer received only in Mexico (B: 541.62; p = 0.010). CONCLUSION: In selected LMICs, receiving family transfers is common among older households, and associated with requiring long-term care. Further research is needed to better understand drivers of observed associations and identify ways in which financial protection of older adults' long-term care needs can be improved.

Reliability of Blue-Emitting Eu2+-Doped Phosphors for Laser-Lighting Applications.

This paper investigates the reliability of blue-emitting phosphors for Near-UV (NUV) laser excitation. By means of a series of thermal stress experiments, and of stress under high levels of optical excitation, we have been able to identify the physical process responsible for the degradation of Eu2+-activated alkaline-earth halophosphate phosphors under typical and extreme operating conditions. In particular, for temperatures equal to or greater than 450 °C the material exhibited a time-dependent drop in the Photo-Luminescence (PL), which was attributed to the thermally induced ionization of the Eu2+ optically active centers. Several analytical techniques, including spatially and spectrally resolved PL, Electron Paramagnetic Resonance (EPR) and X-ray Photo-emission Spectroscopy (XPS) were used to support this hypothesis and to gain insight on the degradation process. By means of further tests, evidence of this degradation process was also found on samples stressed under a relatively low power density of 3 W/mm² at 405 nm. This indicated that the optically (and thermally) induced ionization of the optically active species is the most critical degradation process for this family of phosphorescent material. The operating limits of a second-generation Eu-doped halophosphate phosphor were also investigated by means of short-term stress under optical excitation. The experimental data showed that a threshold excitation intensity for continuous pumping exists. Above this threshold, decay of the steady-state PL performance and non-recoverable degradation of the material were found to take place. This behavior is a consequence of the extremely harsh excitation regime, mainly due to the thermal management capabilities of the substrate material employed for our experimental purposes rather than from intrinsic properties of the phosphors.

Unequal Inequalities: The Stratification of the Use of Formal Care Among Older Europeans.

OBJECTIVES: The general aim of the article is to incorporate the stratification perspective into the study of (long-term) care systems. In particular, 3 issues are investigated: the extents to which (a) personal and family resources influence the likelihood of using formal care in later life; (b) the unequal access to formal care is mediated by differences in the availability of informal support; (c) the relationship between individuals' resources and the use of formal care in old age varies across care regimes and is related to the institutional design of long-term care policies. METHOD: Data from Waves 1 and 2 of the Survey of Health, Ageing and Retirement in Europe for 4 countries: Denmark, Germany, France, and Italy, and population aged at least 65 (N = 9,824) were used. Population-averaged logit models were used. RESULTS: Logit models revealed that in terms of access to formal care: an individual's educational level plays a limited role; family networks function similarly across the countries studied; in general, financial wealth does not have a significant effect; there is a positive relation between income and the use of formal care in Germany and Italy, and no significant relation in France and Denmark; home ownership has a negative effect in Germany and Denmark. On accounting for informal care, inequality associated with individuals' economic resources remains substantially unaltered. DISCUSSION: The study shows that care systems based on services provision grant higher access to formal care and create lower inequalities. Moreover, countries where cash-for-care programs and family responsibilities are more important register inequalities in the use of formal care. Access to informal care does not mediate the distribution of formal care.

An unusual role for the phytyl chains in the photoprotection of the chlorophylls bound to Water-Soluble Chlorophyll-binding Proteins.

Water-Soluble Chlorophyll Proteins (WSCPs) from Brassicaceae are non-photosynthetic proteins which tetramerize upon binding four chlorophyll (Chl) molecules. The bound Chls are highly photostable, despite the lack of bound carotenoids known, in Chl-containing photosynthetic proteins, to act as singlet oxygen and Chl triplet (3Chl) quenchers. Although the physiological function of WSCPs is still unclear, it is likely to be related to their biochemical stability and their resistance to photodegradation. To get insight into the origin of this photostability, the properties of the 3Chl generated in WSCPs upon illumination were investigated. We found that, unlike the excited singlet states, which are excitonic states, the triplet state is localized on a single Chl molecule. Moreover, the lifetime of the 3Chl generated in WSCPs is comparable to that observed in other Chl-containing systems and is reduced in presence of oxygen. In contrast to previous observations, we found that WSCP actually photosensitizes singlet oxygen with an efficiency comparable to that of Chl in organic solvent. We demonstrated that the observed resistance to photooxidation depends on the conformation of the phytyl moieties, which in WSCP are interposed between the rings of Chl dimers, hindering the access of singlet oxygen to the oxidizable sites of the pigments.