A 236-Ghz Fe\u3csup\u3e3+\u3c/sup\u3e EPR Study of Nanoparticles of the Ferromagnetic Room-Temperature Semiconductor Sn\u3csub\u3e1-x\u3c/sub\u3eFe\u3csub\u3ex\u3c/sub\u3eO\u3csub\u3e2\u3c/sub\u3e (\u3cem\u3ex\u3c/em\u3e = 0.005)

High-frequency (236 GHz) electron paramagnetic resonance (EPR) studies of Fe3+ ions at 255 K are reported in a Sn1-xFexO2 powder with x = 0.005, which is a ferromagnetic semiconductor at room temperature. The observed EPR spectrum can be simulated reasonably well as the overlap of spectra due to four magnetically inequivalent high-spin (HS) Fe3+ ions (S = 5/2). The spectrum intensity is calculated, using the overlap I(BL) + (I(HS1) + I(HS2) + I(HS3) + I(HS4)) 9 x e-0.00001xB, where B is the magnetic field intensity in Gauss, I represents the intensity of an EPR line (HS1, HS2, HS3, HS4), and BL stands for the base line (the exponential factor, as found by fitting to the experimental spectrum, is related to the Boltzmann population distribution of energy levels at 255 K, which is the temperature of the sample in the spectrometer). These high-frequency EPR results are significantly different from those at X-band. The large values of the zero-field splitting parameter (D) observed here for the four centers at the high frequency of 236 GHz are beyond the capability of X-band, which can only record spectra of ions only with much smaller D values than those reported here

An X- and Q-band Gd3+ EPR study of a single crystal of EuAlO3: EPR linewidth variation with temperature and low-symmetry effects

Detailed electron paramagnetic resonance (EPR) studies on a single crystal of Gd3+-doped Van-Vleck compound EuAlO3, potentially a phosphorescent/luminescent/laser material, with the Gd3+ ion substituting for the Eu3+ ion, were carried out at X-band (9.2 GHz) over the 77–400 K temperature range. They provide new physical results on magnetic properties of the Eu3+ ion in a low symmetry environment. The asymmetry exhibited by the variation of the Gd3+ EPR line positions for the orientations of the external magnetic field about the Z and X magnetic axes in the ZX plane was ascribed to the existence of low, monoclinic, site symmetry, as revealed by the significant values of the spin-Hamiltonian (SH) parameters and , estimated by fitting all the observed EPR line positions at room temperature for the orientation of the magnetic field in the magnetic ZX plane using a least-square fitting procedure. The temperature dependence of the Gd3+ EPR linewidth is interpreted to be due to the “life-time” broadening, caused by dynamical exchange and dipolar interactions between the impurity Gd3+ ions and the host Eu3+ ions

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Multifrequency Electron Paramagnetic Resonance: Theory and Applications

Filling the gap for a systematic, authoritative, and up-to-date review of this cutting-edge technique, this book covers both low and high frequency EPR, emphasizing the importance of adopting the multifrequency approach to study paramagnetic systems in full detail by using the EPR method. In so doing, it discusses not only the underlying theory and applications, but also all recent advances -- with a final section devoted to future perspectives

Handbook of multifrequency electron paramagnetic resonance: data and techniques

This handbook is aimed to deliver an up-to-date account of some of the recently developed experimental and theoretical methods in EPR, as well as a complete up-to-date listing of the experimentally determined values of multifrequency transition-ion spin Hamiltonian parameters by Sushil Misra, reported in the past 20 years, extending such a listing published by him in the Handbook on Electron Spin Resonance, volume 2. This extensive data tabulation makes up roughly 60% of the book`s content. It is complemented by the first full compilation of hyperfine splittings and g-factors for aminoxyl (ni

Electron paramagnetic resonance study of (La0.33Sm0.67)0.67Sr0.33−xBaxMnO3 (x<0.1): Griffiths phase

Manganite compounds (La0.33Sm0.67)0.67Sr0.33-xBaxMnO3 with light Ba doping (x = 0.01, 0.03, 0.06, 0.09) have been investigated by EPR over the temperature range 110 – 450 K. It was found that the EPR linewidth behavior changed drastically in samples with these low Ba concentrations. For all the samples there was observed a transition from paramagnetic to ferromagnetic phase below the phase-transition temperature. EPR signals characteristic of Griffiths phase were observed in the samples with x = 0.03, 0.06, 0.09. The temperature dependence of the EPR linewidth in the paramagnetic phase was analyzed on the basis of variable-range-hoping model, which explained well the observed data

Theory of EPR lineshape in samples concentrated in paramagnetic spins: Effect of enhanced internal magnetic field on high-field high-frequency (HFHF) EPR lineshape

A theoretial treatment is provided for the calculation of EPR (electron paramagnetic resonance) lineshape as affected by interactions with a cluster of paramagnetic ions in the sample. The internal fields seen by the various paramagnetic ions due to interactions with clusters of paramagnetic ions in their vicinity, as well as the resulting lineshapes, are different at high magnetic fields required in high-frequency EPR. The resulting EPR signals for the various ions are characterized by different g-shifts and lineshapes, so that the overall EPR lineshape, which is an overlap of these, becomes distorted, or even split, from that observed at lower frequencies. The observed EPR lineshapes in MnSO4.H2O powder and K3CrO8 single-crystal samples have been simulated here to show that in these samples, concentrated in paramagnetic spins, the position and lineshapes of EPR signals are significantly modified in high-field high-frequency (HFHF) EPR involving very high magnetic fields. These simulations show that it is important to take into account the effect of enhanced internal fields and modifications of HFHF EPR lineshapes to provide a more accurate interpretation of the observed EPR signals

Anil Complexes of Uranyl Acetate

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Estimation of distance-distribution probabilities from pulsed electron paramagnetic resonance (EPR) data of two dipolar interaction coupled nitroxide spin labels using doubly rotating frames and least-squares fitting

A method, based on the doubly rotating frame (DRF) technique to calculate the basis DEER (Double Electron–Electron Resonance) signals [Physica B: Condensed Matter, 625, 413,511 (2022)] accurately by numerical techniques over a range of $$r$$ values, where $$r$$ is the distance between the two nitroxides in a biradical in a biological system, has been exploited to calculate the probabilities of distance distribution, $$P\left( r \right),$$ by the use of Tikhonov regularization. It is demonstrated here by applying it to the data reported by Lovett et al. [J. Magn. Reson., 223, 98–106 (2012)] on a sample of bis-nitroxide nanowire, P1, in deuterated ortho-terphenyl solvent with 5% BnPy (d14-oTP/BnPy) in semi-rigid state. An improvement in the agreement of the calculated signal with respect to the experimental signal and thus in the probabilities of the distance distribution, $$P\left( r \right)$$, so obtained, is found, as compared to that obtained using the kernel signals based on analytical expressions