Dinuclear, organometallic, transuranium compounds, (Cp′3M)2(μ-4,4′-bpy) (Cp′– = trimethylsilylcyclopentadienide, 4,4′-bpy = 4,4′-bipyridine, M = Ce, Np, Pu), reported herein provide a rare ...opportunity to probe the nature of actinide–carbon bonding. Significant splitting of the f–f transitions results from the unusual coordination environment in these complexes and leads to electronic properties that are currently restricted to organoactinide systems. Structural and spectroscopic characterization in the solid state and in solution for (Cp′3M)2(μ-4,4′-bpy) (M = Np, Pu) are reported, and their structural metrics are compared to a cerium analogue.
Synthetics play an important role in quantitative genetic research and plant breeding, but few studies have investigated the application of genomic prediction (GP) to these populations. Synthetics ...are generated by intermating a small number of parents (Formula: see text and thereby possess unique genetic properties, which make them especially suited for systematic investigations of factors contributing to the accuracy of GP. We generated synthetics in silico from Formula: see text2 to 32 maize (Zea mays L.) lines taken from an ancestral population with either short- or long-range linkage disequilibrium (LD). In eight scenarios differing in relatedness of the training and prediction sets and in the types of data used to calculate the relationship matrix (QTL, SNPs, tag markers, and pedigree), we investigated the prediction accuracy (PA) of Genomic best linear unbiased prediction (GBLUP) and analyzed contributions from pedigree relationships captured by SNP markers, as well as from cosegregation and ancestral LD between QTL and SNPs. The effects of training set size Formula: see text and marker density were also studied. Sampling few parents (Formula: see text) generates substantial sample LD that carries over into synthetics through cosegregation of alleles at linked loci. For fixed Formula: see text, Formula: see text influences PA most strongly. If the training and prediction set are related, using Formula: see text parents yields high PA regardless of ancestral LD because SNPs capture pedigree relationships and Mendelian sampling through cosegregation. As Formula: see text increases, ancestral LD contributes more information, while other factors contribute less due to lower frequencies of closely related individuals. For unrelated prediction sets, only ancestral LD contributes information and accuracies were poor and highly variable for Formula: see text due to large sample LD. For large Formula: see text, achieving moderate accuracy requires large Formula: see text, long-range ancestral LD, and high marker density. Our approach for analyzing PA in synthetics provides new insights into the prospects of GP for many types of source populations encountered in plant breeding.
In recent years, several attempts have been made in plant genetics to detect QTL by using association mapping methods. The objectives of this study were to (i) evaluate various methods for ...association mapping in five plant species and (ii) for three traits in each of the plant species compare the Topt, the restricted maximum likelihood (REML) estimate of the conditional probability that two genotypes carry at the same locus alleles that are identical in state but not identical by descent. In order to compare the association mapping methods based on scenarios with realistic estimates of population structure and familial relatedness, we analyzed phenotypic and genotypic data of rapeseed, potato, sugar beet, maize, and Arabidopsis. For the same reason, QTL effects were simulated on top of the observed phenotypic values when examining the adjusted power for QTL detection.
The correlation between the Topt values identified using REML deviance profiles and profiles of the mean of squared difference between observed and expected P values was 0.83.
The mixed-model association mapping approaches using a kinship matrix, which was based on Topt, were more appropriate for association mapping than the recently proposed QK method with respect to the adherence to the nominal alpha level and the adjusted power for QTL detection. Furthermore, we showed that Topt differs considerably among the five plant species but only marginally among different traits.
Three samarium(II) crown ether complexes, Sm(15-crown-5)2I2 (1), Sm(15-crown-5)2I2·CH3CN (2), and Sm(benzo-15-crown-5)2I2 (3), have been prepared via the reaction of SmI2 with the ...corresponding crown ether in either THF or acetonitrile in good to moderate yields. The compounds have been characterized by single crystal X-ray diffraction and a variety of spectroscopic techniques. In all cases, the Sm(II) centers are sandwiched between two crown ether molecules and are bound by the five etheric oxygen atoms from each crown ether to yield 10-coordinate environments. Despite the higher symmetry crystal class of 1 (R3c), the samarium center resides on a general position, whereas in 2 and 3 (both in P21/c) the metal centers lie upon inversion centers. Moreover, the complexes in 2 and 3 are approximated well by D 5d symmetry. The molecule in 1, however, is distorted from idealized D 5d symmetry, and the crown ethers are more puckered than observed in 2 and 3. All three complexes luminesce in the NIR at low temperatures. However, the nature of the luminescence differs between the three compounds. 1 exhibits broadband photoluminescence at 20 °C but at low temperatures transitions to narrow peaks. 2 only exhibits nonradiative decay at 20 °C and at low temperatures retains a mixture of broadband and fine transitions. Finally, 3 displays broadband luminescence regardless of temperature. Spin–orbit (SO) CASSCF calculations reveal that the outer-sphere iodide anions influence whether broadband luminescence from 5d → 4f or fine 4f → 4f transitions occur through the alteration of symmetry around the metal centers and the nature of the excited states as a function of temperature.
Despite its importance to agriculture, the genetic basis of heterosis is still not well understood. The main competing hypotheses include dominance, overdominance, and epistasis. NC design III is an ...experimental design that has been used for estimating the average degree of dominance of quantitative trait loci (QTL) and also for studying heterosis. In this study, we first develop a multiple-interval mapping (MIM) model for design III that provides a platform to estimate the number, genomic positions, augmented additive and dominance effects, and epistatic interactions of QTL. The model can be used for parents with any generation of selfing. We apply the method to two data sets, one for maize and one for rice. Our results show that heterosis in maize is mainly due to dominant gene action, although overdominance of individual QTL could not completely be ruled out due to the mapping resolution and limitations of NC design III. For rice, the estimated QTL dominant effects could not explain the observed heterosis. There is evidence that additive x additive epistatic effects of QTL could be the main cause for the heterosis in rice. The difference in the genetic basis of heterosis seems to be related to open or self pollination of the two species. The MIM model for NC design III is implemented in Windows QTL Cartographer, a freely distributed software.
Selenium is of great concern owing to its acutely toxic characteristic at elevated dosage and the long-term radiotoxicity of 79Se. The contents of selenium in industrial wastewater, agricultural ...runoff, and drinking water have to be constrained to a value of 50 μg/L as the maximum concentration limit. We reported here the selenium uptake using a structurally well-defined cationic layered rare earth hydroxide, Y2(OH)5Cl·1.5H2O. The sorption kinetics, isotherms, selectivity, and desorption of selenite and selenate on Y2(OH)5Cl·1.5H2O at pH 7 and 8.5 were systematically investigated using a batch method. The maximum sorption capacities of selenite and selenate are 207 and 124 mg/g, respectively, both representing the new records among those of inorganic sorbents. In the low concentration region, Y2(OH)5Cl·1.5H2O is able to almost completely remove selenium from aqueous solution even in the presence of competitive anions such as NO3 –, Cl–, CO3 2–, SO4 2–, and HPO4 2–. The resulting concentration of selenium is below 10 μg/L, well meeting the strictest criterion for the drinking water. The selenate on loaded samples could be desorbed by rinsing with concentrated noncomplexing NaCl solutions whereas complexing ligands have to be employed to elute selenite for the material regeneration. After desorption, Y2(OH)5Cl·1.5H2O could be reused to remove selenate and selenite. In addition, the sorption mechanism was unraveled by the combination of EDS, FT-IR, Raman, PXRD, and EXAFS techniques. Specifically, the selenate ions were exchanged with chloride ions in the interlayer space, forming outer-sphere complexes. In comparison, besides anion exchange mechanism, the selenite ions were directly bound to the Y3+ center in the positively charged layer of Y2(OH)5(H2O)+ through strong bidentate binuclear inner-sphere complexation, consistent with the observation of the higher uptake of selenite over selenate. The results presented in this work confirm that the cationic layered rare earth hydroxide is an emerging and promising material for efficient removal of selenite and selenate as well as other anionic environmental pollutants.
Key message
Inclusion of historical training data improved the genomics-based prediction of performance of maize hybrids, the extent depending on the phenotypic trait and genotype-by-year ...interaction.
Prediction of hybrid performance using existing phenotypic data on previous hybrids combined with molecular data collected on the parent lines allows to identify the most promising candidates from a huge number of possible hybrids at an early stage. Phenotypic data on yield and dry matter of 1970 grain maize hybrids from 19 years of a public breeding program were aggregated considering the underlying structure of factorial sets of hybrids. Pedigree records and 50 K SNP data were collected on their 170 Dent and 127 Flint parent lines. The performance of untested hybrids was predicted by best linear unbiased predictors (BLUP) on basis of pedigree or genomic data. For composition of training sets (TRN) and test sets (TST), three schemes for collecting factorials from specific years were employed which resulted in 490 scenarios. For each scenario, the predictive ability and genomic relationship between TRN and TST hybrids were determined. For extended TRNs, where earlier years were successively added to the TRN, the maximum relationship increased and the predictive ability improved, with the extent of the latter depending on the phenotypic trait and its genotype-by-year interaction. Genomic BLUP outperformed pedigree BLUP and better utilized the early years’ data, especially for prediction of hybrids from factorials in a more distant future. This study on hybrid prediction in grain maize illustrated that including historical phenotypic data for training, although consisting of less related genotypes, can improve genomic prediction and enables optimization of hybrid variety development.
Many consider femoral nerve block the gold standard in pain management following knee arthroplasty. Local infiltration analgesia is an alternate approach that applies the concept of surgical wound ...infiltration with local anaesthetics. This meta-analysis aims to compare both analgesic treatments for analgesia and functional outcomes after total knee arthroplasty. This meta-analysis was performed according to the PRISMA statement guidelines. The primary outcomes were cumulative i.v. morphine consumption, pain scores at rest and on movement on postoperative day one (analogue scale,0–10). Secondary outcomes included range of motion, quadriceps muscle strength, length of stay and rates of complications (neurologic events, cardiovascular events, falls and knee infections). Fourteen trials, including 1122 adult patients were identified. There was no difference in i.v. morphine consumption (mean difference: −2.0 mg; 95% CI: −4.9, 0.9 mg; I2+69%; P+0.19), pain scores at rest (mean difference: −0.1; 95% CI: −0.4, 0.3; I2+72%; P+0.80) and pain scores on movement (mean difference: 0.2; 95% CI: −0.5, 0.8; I2+80%; P+0.64) on postoperative day one (a negative mean difference favours local infiltration analgesia). The qualities of evidence for our primary outcomes were moderate according to the GRADE system. There were no clinical differences in functional outcomes or rates of complications. Complication rates were captured by three trials or fewer with exception of knee infection, which was sought by eight trials. Local infiltration analgesia provides similar postoperative analgesia after total knee arthroplasty to femoral nerve block. Although this meta-analysis did not capture any difference in rates of complications, the low number of trials that specifically sought these outcomes dictates caution.
[Am(C5Me4H)3]: An Organometallic Americium Complex Goodwin, Conrad A. P.; Su, Jing; Albrecht‐Schmitt, Thomas E. ...
Angewandte Chemie (International ed.),
August 19, 2019, Letnik:
58, Številka:
34
Journal Article
Recenzirano
Odprti dostop
We report the small‐scale synthesis, isolated yield, single‐crystal X‐ray structure, 1H NMR solution spectroscopy /solid‐state UV/Vis‐nIR spectroscopy, and density functional theory (DFT)/ab initio ...wave function theory calculations on an Am3+ organometallic complex, Am(C5Me4H)3 (1). This constitutes the first quantitative data on Am−C bonding in a molecular species.
Captain americium: The first structural characterization of an Am−C molecular interaction along with a suite of standard synthetic chemistry characterization techniques, including both 1H NMR and solution UV/Vis‐NIR spectroscopy have been performed. Detailed theoretical models of the electronic structure show excellent agreement with experimental data.
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