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The aim of this study was to evaluate the foliar application of silicon on the silicon (Si) leaf content, photosynthetic parameters, and fruit production and quality of tomato. We evaluated five silicon concentrations via foliar application: 0 (control), 1, 2, 3 and 4 g L−1 of Si in tomatoes, using stabilized potassium copper silicate (SiKCuE) as a Si source. The foliar applications were carried out at the beginning of flowering, at intermediate flowering, and at full flowering. One week after the third application of Si, the relative chlorophyll index (RCI), physiological quality and Si content were measured on the diagnostic leaf. When the fruits had reached full maturity, they were harvested, the productivity was estimated, and the firmness and soluble solids content were evaluated. Foliar application of Si, proved to be efficient in increasing the leaf content of the beneficial element in tomato plants. The Si concentration of 2.34 g L−1 resulted in a leaf silicon content of 17.3 g kg−1, indicating the ideal Si content in tomato leaves, related to higher productivity (124.4 t ha−1). As a result foliar application of Si as SiKCuE is efficient in supplying Si via leaf to tomato plants, favoring photosynthetic parameters and fruit production and quality by increasing, accumulation of soluble solids firmness. The application of Si proved to be economically viable for all evaluated concentrations, allowing maximum profit to be obtained, US$ 6,679.00 ha−1 at a concentration of 3 g L−1 de Si, which produced 12% more than the control treatment, without the addition of silicon. [ABSTRACT FROM AUTHOR]

A very simple and fast immobilization technique based on ion exchange was investigated to improve the thermal stability of acid phosphatase from wheat germ and potato. Immobilization was not efficient for the DEAE-sepharose, and MANAE-agarose supports. On the other hand, Toyopearl DEAE-650s proved to be a promising support, with immobilization yield above 95% and recovery of activity above 85% for both enzymes. A second step was introduced in the immobilization protocol to improve the thermal stability of these biocatalysts. For this, oxidation and reduction of glycosidic chains of acid phosphatase were carried out, allowing the formation of aldehyde groups and subsequent interaction with the amine groups to further stabilize the different forms (free and immobilized). Both biocatalysts showed residual activity after 1 hour of inactivation at the temperature of 60 °C, a fact not observed for the free enzyme. The wheat germ acid phosphatase derivative was the most stable, with residual activity of 66.7% for the only immobilized derivative and 76.2% for the oxidized/reduced derivative. Also, the derivatives prepared by ion exchange adsorption on Toyopearl (TOYO), followed by oxidation/reduction and intramolecular crosslinking, were approximately 15 and 41 times more stable than the free enzyme from wheat germ. [ABSTRACT FROM AUTHOR]

X-ray free-electron laser sources enable time-resolved X-ray studies with unmatched temporal resolution. To fully exploit ultrashort X-ray pulses, timing tools are essential. However, new high repetition rate X-ray facilities present challenges for currently used timing tool schemes. Here we address this issue by demonstrating a sensitive timing tool scheme to enhance experimental time resolution in pump-probe experiments at very high pulse repetition rates. Our method employs a self-referenced detection scheme using a time-sheared chirped optical pulse traversing an X-ray stimulated diamond plate. By formulating an effective medium theory, we confirm subtle refractive index changes, induced by sub-milli-Joule intense X-ray pulses, that are measured in our experiment. The system utilizes a Common-Path-Interferometer to detect X-ray-induced phase shifts of the optical probe pulse transmitted through the diamond sample. Owing to the thermal stability of diamond, our approach is well-suited for MHz pulse repetition rates in superconducting linear accelerator-based free-electron lasers. In time-resolved measurements it is crucial to know the time delay between the exciting and probing light pulses. Here the authors demonstrate a self-referencing common-path interferometer method measuring the arrival time between the X-ray free electron laser and the optical pulse to the target and thus their inherent timing jitter. [ABSTRACT FROM AUTHOR]

Sugarcane stands out as the most used renewable energy source in Brazil. Its yield and adaptation respond perfectly to tropical edaphoclimatic conditions. This study evaluates the K dynamics in the soil–plant system for sugarcane crops under tropical conditions. Treatments were arranged in randomized blocks design with five doses of K2O (0, 50, 100, 150, and 200 kg ha−1) and five replications. The following analyses were performed: K content in the soil, plant uptake, availability and decomposition of sugarcane straw, and K balance in the soil–plant system. Data on response variables were subjected to the analysis of variance and F test at 5% probability. Quantitative factors were subjected to polynomial regression analysis by selecting the model of higher significance. The potassium dose of 200 kg ha−1 increased K levels at 0.8 m by 20% relative to the control. After 70 days, 50% of the 79 kg K ha−1 was available from sugarcane straw mineralization. The treatment that improved K in soil was 150 kg ha−1 of K annual application. This dose causes a positive balance of K in the soil with 133.32 kg ha−1 year−1. [ABSTRACT FROM AUTHOR]

We examine the link between the quality of fiscal governance and access to market-based external finance. Stronger fiscal governance is associated with improvements in several indicators of market access, including a higher likelihood of issuing sovereign bonds and having a sovereign credit rating, receiving stronger ratings, and obtaining lower spreads. Using the more granular information on quality of fiscal governance from Public Expenditure and Financial Accountability (PEFA) assessments for 89 emerging and developing economies, we find that similar indicators of market access are correlated with sound public financial management practices, especially those that improve budget transparency and reporting, debt management, and fiscal strategy. [ABSTRACT FROM AUTHOR]

Duraplasty is necessary in nearly 30% of all neurological surgeries. Different tissues and materials have been evaluated in dura mater repair or as dural substitutes in neurosurgery. The aim was to evaluate the biocompatibility of the bacterial cellulose (BC) membranes, produced from sugarcane molasses, for dural defect repair in rats. Forty adults males Wistar rats divided into two groups: a control (ePTFE) and an experimental (BC). Bilateral frontoparietal craniectomy was performed, and a dural defect was created. The arachnoid underlying defect was disrupted with a narrow hook. The animals were observed for 120 days. There were no cases of infection, cerebrospinal fluid fistulae, delayed hemorrhages, behavior disturbances, seizures and palsies. The BC membrane showed to have suitable biocompatibility properties, was not induced immune reaction, nor chronic inflammatory response and absence of neurotoxicity signals. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A series of vanadium compounds was studied by K-edge X-ray absorption (XAS) and K $$\beta $$ X-ray emission spectroscopies (XES). Qualitative trends within the datasets, as well as comparisons between the XAS and XES data, illustrate the information content of both methods. The complementary nature of the chemical insight highlights the success of this dual-technique approach in characterizing both the structural and electronic properties of vanadium sites. In particular, and in contrast to XAS or extended X-ray absorption fine structure (EXAFS), we demonstrate that valence-to-core XES is capable of differentiating between ligating atoms with the same identity but different bonding character. Finally, density functional theory (DFT) and time-dependent DFT calculations enable a more detailed, quantitative interpretation of the data. We also establish correction factors for the computational protocols through calibration to experiment. These hard X-ray methods can probe vanadium ions in any oxidation or spin state, and can readily be applied to sample environments ranging from solid-phase catalysts to biological samples in frozen solution. Thus, the combined XAS and XES approach, coupled with DFT calculations, provides a robust tool for the study of vanadium atoms in bioinorganic chemistry. [ABSTRACT FROM AUTHOR]

In haemoglobin the change from the low-spin (LS) hexacoordinated haem to the high spin (HS, S = 2) pentacoordinated domed deoxy-myoglobin (deoxyMb) form upon ligand detachment from the haem and the reverse process upon ligand binding are what ultimately drives the respiratory function. Here we probe them in the case of Myoglobin-NO (MbNO) using element- and spin-sensitive femtosecond Fe Kα and Kβ X-ray emission spectroscopy at an X-ray free-electron laser (FEL). We find that the change from the LS (S = 1/2) MbNO to the HS haem occurs in ~800 fs, and that it proceeds via an intermediate (S = 1) spin state. We also show that upon NO recombination, the return to the planar MbNO ground state is an electronic relaxation from HS to LS taking place in ~30 ps. Thus, the entire ligand dissociation-recombination cycle in MbNO is a spin cross-over followed by a reverse spin cross-over process. The change from low-spin hexacoordinated to high-spin pentacoordinated domed form in heam upon ligand detachment and the reverse process underlie the respiratory function. The authors, using femtosecond time-resolved X-ray emission spectroscopy, capture the transient states connecting the two forms in myoglobin-NO upon NO photoinduced detachment. [ABSTRACT FROM AUTHOR]

Disentangling the strong interplay between electronic and nuclear degrees of freedom is essential to achieve a full understanding of excited state processes during ultrafast nonadiabatic chemical reactions. However, the complexity of multi-dimensional potential energy surfaces means that this remains challenging. The energy flow during vibrational and electronic relaxation processes can be explored with structural sensitivity by probing a nuclear wavepacket using femtosecond time-resolved X-ray Absorption Near Edge Structure (TR-XANES). However, it remains unknown to what level of detail vibrational motions are observable in this X-ray technique. Herein we track the wavepacket dynamics of a prototypical [Cu(2,9-dimethyl-1,10-phenanthroline)2]+ complex using TR-XANES. We demonstrate that sensitivity to individual wavepacket components can be modulated by the probe energy and that the bond length change associated with molecular breathing mode can be tracked with a sub-Angstrom resolution beyond optical-domain observables. Importantly, our results reveal how state-of-the-art TR-XANES provides deeper insights of ultrafast nonadiabatic chemical reactions. Nonadiabatic excited state processes involve mixing of electronic and nuclear wavefunctions, which are difficult to disentangle. Here the authors explore by time-resolved X-ray absorption near edge structure the wavepacket dynamics of a copper(I)-phenanthroline complex, resolving different vibrational modes. [ABSTRACT FROM AUTHOR]