Influence of the Rare Earth Cation on the Magnetic Properties of Layered 12R-Ba4M4+Mn3O12 (M = Ce, Pr) Perovskites.

Material design is increasingly used to realize desired functional properties, and the perovskite structure family is one of the richest and most diverse: perovskites are employed in many applications due to their structural flexibility and compositional diversity. Hexagonal, layered perovskite structures with chains of face-sharing transition metal oxide octahedra have attracted great interest as quantum materials due to their magnetic and electronic properties. Ba4MMn3O12, a member of the "12R" class of hexagonal, layered perovskites, contains trimers of face-sharing MnO6 octahedra that are linked by a corner-sharing, bridging MO6 octahedron. Here, we investigate cluster magnetism in the Mn3O12 trimers and the role of this bridging octahedron on the magnetic properties of two isostructural 12R materials by systematically changing the M4+ cation from nonmagnetic Ce4+ (f0) to magnetic Pr4+ (f1). We synthesized 12R-Ba4MMn3O12 (M= Ce, Pr) with high phase purity and characterized their low-temperature crystal structures and magnetic properties. Using substantially higher purity samples than previously reported, we confirm the frustrated antiferromagnetic ground state of 12R-Ba4PrMn3O12 below TN ≈ 7.75 K and explore the cluster magnetism of its Mn3O12 trimers. Despite being atomically isostructural with 12R-Ba4CeMn3O12, the f1 electron associated with Pr4+ causes much more complex magnetic properties in 12R-Ba4PrMn3O12. In 12R-Ba4PrMn3O12, we observe a sharp, likely antiferromagnetic transition at T2 ≈ 12.15 K and an additional transition at T1 ≈ 200 K, likely in canted antiferromagnetic order. These results suggest that careful variation of composition within the family of hexagonal, layered perovskites can be used to tune material properties using the complex role of the Pr4+ ion in magnetism.

Cancer mortality after kidney transplantation: A multicenter cohort study in Italy.

Kidney transplant (KT) recipients are known to be at risk of developing several cancer types; however, cancer mortality in this population is underinvestigated. Our study aimed to assess the risk of cancer death among Italian KT recipients compared to the corresponding general population. A cohort study was conducted among 7373 individuals who underwent KT between 2003 and 2020 in 17 Italian centers. Date and cause of death were retrieved until 31 December 2020. Indirect standardization was used to estimate standardized mortality ratios (SMRs) and corresponding 95% confidence intervals (CIs). Cancer was the most common cause of death among the 7373 KT recipients, constituting 32.4% of all deaths. A 1.8-fold excess mortality (95% CI: 1.59-2.09) was observed for all cancers combined. Lymphomas (SMR = 6.17, 95% CI: 3.81-9.25), kidney cancer (SMR = 5.44, 95% CI: 2.97-8.88) and skin melanoma (SMR = 3.19, 95% CI: 1.03-6.98) showed the highest excess death risks. In addition, SMRs were increased about 1.6 to 3.0 times for cancers of lung, breast, bladder and other hematopoietic and lymphoid tissues. As compared to the general population, relative cancer mortality risk remained significantly elevated in all age groups though it decreased with increasing age. A linear temporal increase in SMR over time was documented for all cancers combined (P < .01). Our study documented significantly higher risks of cancer death in KT recipients than in the corresponding general population. Such results support further investigation into the prevention and early detection of cancer in KT recipients.

Variation in Post-Transplant Cancer Incidence among Italian Kidney Transplant Recipients over a 25-Year Period.

This cohort study examined 25-year variations in cancer incidence among 11,418 Italian recipients of kidney transplantation (KT) from 17 Italian centers. Cancer incidence was examined over three periods (1997-2004; 2005-2012; and 2013-2021) by internal (Incidence rate ratio-IRR) and external (standardized incidence ratios-SIR) comparisons. Poisson regression was used to assess trends. Overall, 1646 post-transplant cancers were diagnosed, with incidence rates/1000 person-years ranging from 15.5 in 1997-2004 to 21.0 in 2013-2021. Adjusted IRRs showed a significant reduction in incidence rates across periods for all cancers combined after exclusion of nonmelanoma skin cancers (IRR = 0.90, 95% confidence interval-CI: 0.76-1.07 in 2005-2012; IRR = 0.72, 95% CI: 0.60-0.87 in 2013-2021 vs. 1997-2004; Ptrend < 0.01). In site-specific analyses, however, significant changes in incidence rates were observed only for Kaposi's sarcoma (KS; IRR = 0.37, 95% CI: 0.24-0.57 in 2005-2012; IRR = 0.09, 95% CI: 0.04-0.18 in 2013-2021; Ptrend < 0.01). As compared to the general population, the overall post-transplant cancer risk in KT recipients was elevated, with a decreasing magnitude over time (SIR = 2.54, 95% CI: 2.26-2.85 in 1997-2004; SIR = 1.99, 95% CI: 1.83-2.16 in 2013-2021; Ptrend < 0.01). A decline in SIRs was observed specifically for non-Hodgkin lymphoma and KS, though only the KS trend retained statistical significance after adjustment. In conclusion, apart from KS, no changes in the incidence of other cancers over time were observed among Italian KT recipients.

The impact of cancer on the risk of death with a functioning graft of Italian kidney transplant recipients.

This study assessed the impact of cancer on the risk of death with a functioning graft of kidney transplant (KT) recipients, as compared to corresponding recipients without cancer. A matched cohort study was conducted using data from a cohort of 13 245 individuals who had undergone KT in 17 Italian centers (1997-2017). Cases were defined as subjects diagnosed with any cancer after KT. For each case, two controls matched by gender, age, and year at KT were randomly selected from cohort members who were cancer-free at the time of diagnosis of the index case. Overall, 292 (20.5%) deaths with a functioning graft were recorded among 1425 cases and 238 (8.4%) among 2850 controls. KT recipients with cancer had a greater risk of death with a functioning graft (hazard ratio, HR = 3.31) than their respective controls. This pattern was consistent over a broad range of cancer types, including non-Hodgkin lymphoma (HR = 33.09), lung (HR = 20.51), breast (HR = 8.80), colon-rectum (HR = 3.51), and kidney (HR = 2.38). The survival gap was observed throughout the entire follow-up period, though the effect was more marked within 1 year from cancer diagnosis. These results call for close posttransplant surveillance to detect cancers at earlier stages when treatments are more effective in improving survival.

Predictive Models for the Functional Recovery of Transplanted Kidney.

BACKGROUND: Renal transplantation is the gold standard treatment for end-stage renal disease, however, in 20% of cases, the graft develops a delayed graft function (DGF) that is associated with both early and late worsening of the outcome. The aim of this study was to examine and validate in a population of transplanted patients the appropriateness of the predictive score systems of DGF available to identify patients who might take advantage of a tailored immunosuppressive therapy. MATERIALS AND METHODS: We conducted a systematic review of the literature to identify articles concerning scoring systems predicting DGF to identify those applicable to the study population and subsequently comparing their appropriateness for defining the most accurate one. RESULTS: From an analysis of the scientific literature, we found 7 scoring systems predicting DGF. Of these, 3 can be calculated for the study population. We enrolled 247 renal transplants in the study. DGF was recorded in 41 cases (15.95%). The Irish score recognized 25 of 41 cases (60.98%), the Jeldres score 41 of 41 cases (100%), and the Chapal score only 7 of 41 (17.07%). Although the Irish score did not identify all cases of DGF, the analysis of data revealed that it is the most accurate, with area under the receiver operating characteristic almost overlapping. CONCLUSIONS: The study resulted in some interesting and promising conclusions about the predictability of DGF, defining the Irish score as the most reliable. This result can be considered the fundamental requirement to develop a custom therapeutic algorithm to be applied to all recipients with higher probability of developing DGF.

Air separation via two-step solar thermochemical cycles based on SrFeO3-δ and (Ba,La)0.15Sr0.85FeO3-δ perovskite reduction/oxidation reactions to produce N2: rate limiting mechanism(s) determination.

Two-step solar thermochemical cycles based on reversible reactions of SrFeO3-δ and (Ba,La)0.15Sr0.85FeO3-δ perovskites were considered for air separation. The cycle steps encompass (1) the thermal reduction of SrFeO3-δ or (Ba,La)0.15Sr0.85FeO3-δ perovskites driven by concentrated solar irradiation and (2) oxidation in air to remove O2 and produce N2. Rate limiting mechanisms were examined for both reactions using a combination of isothermal and non-isothermal thermogravimetry for temperature-swings between 673 and 1373 K, heating rates of 10, 20, and 50 K min-1, and O2 pressure-swings between 20% O2/Ar and 100% Ar at atmospheric pressure. Evolved O2 and associated lag due to transport behavior were measured with gas chromatography and used with measured sample temperatures to predict equilibrium compositions from a compound energy formalism thermodynamic model. Measured and predicted chemical equilibrium changes in deviation from stoichiometry were compared. Rapid chemical kinetics were observed as the samples equilibrated rapidly for all conditions, indicative that heat and mass transfer were the rate limiting mechanisms. The effects of bulk diffusion (or gas diffusion through the bed or pellet) were examined using pelletized and loose powdered samples and determined to have no discernable impact.

Indocyanine Green Angiography for Quality Assessment of the Kidney During Transplantation: An Outcome Predictor Prospective Study.

BACKGROUND: Microvascular damage is the main cause of delayed graft function (DGF) after kidney transplant. Assessing its extent may be helpful in predicting DGF to achieve better postoperative management, especially in terms of an immunosuppressive regimen. Our aim was to explore the capability of intraoperative indocyanine green (ICG) angiography to examine the microvasculature of the kidney. METHODS: We conducted a prospective cohort study on 37 kidney transplant recipients in a high-volume kidney transplant center. During surgery, after graft implant, an ICG angiography was performed through a high-definition Storz camera system (Karl Storz GmbH, Tuttlingen, Germany) with successive quantitative assessment of fluorescence using Icy bioimage analysis. RESULTS: All transplanted kidneys that showed immediate recovery of their function had a fluorescent intensity ≥49.953 with a mean of 96.930 ± 21. The fluorescence intensity for kidneys that showed a delayed recovery of their function never exceeded 55.648, and the mean was 37.718 ± 13. The difference between the 2 groups was statistically significant with a P value < .001. The only kidney that never recovered showed a fluorescence intensity consistently <25.220, the lowest detected. CONCLUSIONS: This study demonstrates that intraoperative ICG angiography may be used to assess the microvasculature of the graft. A statistically significant difference in terms of fluorescent intensity can be highlighted between kidneys that immediately recover their function and those with delayed recovery. Further larger studies are needed to confirm the capability of the technique to predict DGF to optimize the transplanted patients' management.

Compositional and operational impacts on the thermochemical reduction of CO2 to CO by iron oxide/yttria-stabilized zirconia.

Ferrites have potential for use as active materials in solar-thermochemical cycles because of their versatile redox chemistry. Such cycles utilize solar-thermal energy for the production of hydrogen from water and carbon monoxide from carbon dioxide. Although ferrites offer the potential for deep levels of reduction (e.g., stoichiometric conversion of magnetite to wüstite) and correspondingly large per-cycle product yields, in practice reactions are limited to surface regions made smaller by rapid sintering and agglomeration. Combining ferrites with zirconia or yttria-stabilized zirconia (YSZ) greatly improves the cyclability of the ferrites and enables a move away from powder to monolithic systems. We have studied the behavior of iron oxides composited with YSZ using thermogravimetric analysis under operando conditions. Samples in which the iron was fully dissolved within the YSZ matrix showed greater overall extent of thermochemical redox and higher rate of reaction than samples with equal iron loading but in which the iron was only partially dissolved, with the rest existing as agglomerates of iron oxide within the ceramic matrix. Varying the yttria content of the YSZ revealed a maximum thermochemical capacity (yield per cycle) for 6 mol% Y2O3 in YSZ. The first thermochemical redox cycle performed for each sample resulted in a net mass loss that was proportional to the iron oxide loading in the material and was stoichiometrically consistent with complete reduction of Fe2O3 to Fe3O4 and further partial reduction of the Fe3O4 to FeO. Mass gains upon reaction with CO2 were consistent with re-oxidation of the FeO fraction back to Fe3O4. The Fe dissolved in the YSZ matrix, however, is capable of cycling stoichiometrically between Fe3+ and Fe2+. Varying the re-oxidation temperature between 1000 and 1200 °C highlighted the trade-off between re-oxidation rate and equilibrium limitations.

An A- and B-Site Substitutional Study of SrFeO3-δ Perovskites for Solar Thermochemical Air Separation.

An A­ and B­site substitutional study of SrFeO3-δ perovskites (A'xA1-xB'yB1-yO3-δ, where A = Sr and B = Fe) was performed for a two­step solar thermochemical air separation cycle. The cycle steps encompass (1) the thermal reduction of A'xSr1-xB'yFe1-yO3-δ driven by concentrated solar irradiation and (2) the oxidation of A'xSr1-xB'yFe1-yO3-δ in air to remove O2, leaving N2. The oxidized A'xSr1-xB'yFe1-yO3-δ is recycled back to the first step to complete the cycle, resulting in the separation of N2 from air and concentrated solar irradiation. A-site substitution fractions between 0 ≤ x ≤ 0.2 were examined for A' = Ba, Ca, and La. B-site substitution fractions between 0 ≤ y ≤ 0.2 were examined for B' = Cr, Cu, Co, and Mn. Samples were prepared with a modified Pechini method and characterized with X-ray diffractometry. The mass changes and deviations from stoichiometry were evaluated with thermogravimetry in three screenings with temperature- and O2 pressure-swings between 573 and 1473 K and 20% O2/Ar and 100% Ar at 1 bar, respectively. A' = Ba or La and B' = Co resulted in the most improved redox capacities amongst temperature- and O2 pressure-swing experiments.

Congenital cystic adenomatoid malformation in adults, presenting as a single cyst.

Congenital cystic adenomatoid malformations are lung anomalies usually detected prenatally or in newborns and infants. Type 1 congenital cystic adenomatoid malformations appears as a multicystic lesion, with cysts up to 2 cm in diameter, or as a single large cyst. In the latter case, when detected in adults, the preoperative diagnosis is challenging because congenital cystic adenomatoid malformations can be confused with other more common lesions. We describe two cases of uniloculated type 1 congenital cystic adenomatoid malformation in adults. In both cases, the preoperative clinical diagnosis was missed and the patients were surgically treated with lung-sparing cyst resections.

Ordered ferrimagnetic form of ferrihydrite reveals links among structure, composition, and magnetism.

The natural nanomineral ferrihydrite is an important component of many environmental and soil systems and has been implicated as the inorganic core of ferritin in biological systems. Knowledge of its basic structure, composition, and extent of structural disorder is essential for understanding its reactivity, stability, and magnetic behavior, as well as changes in these properties during aging. Here we investigate compositional, structural, and magnetic changes that occur upon aging of "2-line" ferrihydrite in the presence of adsorbed citrate at elevated temperature. Whereas aging under these conditions ultimately results in the formation of hematite, analysis of the atomic pair distribution function and complementary physicochemical and magnetic data indicate formation of an intermediate ferrihydrite phase of larger particle size with few defects, more structural relaxation and electron spin ordering, and pronounced ferrimagnetism relative to its disordered ferrihydrite precursor. Our results represent an important conceptual advance in understanding the nature of structural disorder in ferrihydrite and its relation to the magnetic structure and also serve to validate a controversial, recently proposed structural model for this phase. In addition, the pathway we identify for forming ferrimagnetic ferrihydrite potentially explains the magnetic enhancement that typically precedes formation of hematite in aerobic soil and weathering environments. Such magnetic enhancement has been attributed to the formation of poorly understood, nano-sized ferrimagnets from a ferrihydrite precursor. Whereas elevated temperatures drive the transformation on timescales feasible for laboratory studies, our results also suggest that ferrimagnetic ferrihydrite could form naturally at ambient temperature given sufficient time.

Characterization of a rat model to study acute neuroinflammation on histopathological, biochemical and functional outcomes.

Neuroinflammation is one of the events occurring after acute brain injuries. The aim of the present report was to characterize a rat model to study acute neuroinflammation on the histopathological, biochemical and functional outcomes. Lipopolysaccharide (LPS), known as a strong immunostimulant, was directly injected into the hippocampus. The spatiotemporal evolution of inducible NOS (iNOS) and cell death was studied from 6 h to 7 days. A perfect time course correlation was observed between iNOS immunoreactivity and iNOS activity showing an acute, expansive and transient iNOS induction in the hippocampus with a peak at 24 h. It was associated with a marked increase in NO metabolite (NO(x)) levels, and a high level of myeloperoxidase (MPO) activity. This inflammation precedes a massive cellular loss including at least neurons and astrocytes, and a drop of constitutive NOS activity, restrictive to the ipsilateral hippocampus from 48 h after LPS injection. Moreover, sensorimotor function impairment occurred from 24 h to 7 days with a maximum at 24 h post-LPS injection. Therefore, we characterized an in vivo model of acute neuroinflammation and neurodegeneration, in relation with a neurological deficit, which may be a powerful tool for mechanistic studies and for further evaluation of the potential neuroprotective agents.

Renal transplantation. Strategies to prevent organ rejection--the role of an inter-regional reference center.

This paper summarizes the role of the Inter-Regional Reference Center (RC) of the North Italy Transplant program (NITp), in coordinating a donor procurement and organ transplantation network, with a special focus on the strategies to minimize immunological risk and complications after transplantation. In the NITp, patients enrolled on the renal transplantation (RT) waiting list are typed for HLA-A,B,DRB1 antigens with a genomic method. They are periodically screened for the presence of lymphocytotoxic antibodies in their serum by the RC and their suitability to receive the transplant is checked periodically. Cadaver kidney allocation is ruled by a computerized algorithm, named NITK3, established in 1997, which aims at ensuring quality, equity, transparency and traceability during all the phases of the allocation decision-making process. NITK3 has been set up by the NITp Working Group on the basis of biological, medical and administrative criteria and it is periodically reviewed after the analysis of transplant results. In this paper, we show the results of a preliminary analysis of RTs performed from 1998 to 2002 in nine out of sixteen centers of the NITp area, which demonstrates the general quality of the NITp program in terms of patients and graft survival and the special attention to the patients at higher immunological risk.