New Eremophilane-Type Sesquiterpenes from the Marine Sediment-Derived Fungus Emericellopsis maritima BC17 and Their Cytotoxic and Antimicrobial Activities.

The fungal strain BC17 was isolated from sediments collected in the intertidal zone of the inner Bay of Cadiz and characterized as Emericellopsis maritima. On the basis of the one strain-many compounds (OSMAC) approach, four new eremophilane-type sesquiterpenes (1-4), together with thirteen known derivatives (5-17) and two reported diketopiperazines (18, 19), were isolated from this strain. The chemical structures and absolute configurations of the new compounds were determined through extensive NMR and HRESIMS spectroscopic studies and ECD calculation. Thirteen of the isolated eremophilanes were examined for cytotoxic and antimicrobial activities. PR toxin (16) exhibited cytotoxic activity against HepG2, MCF-7, A549, A2058, and Mia PaCa-2 human cancer cell lines with IC50 values ranging from 3.75 to 33.44 µM. (+)-Aristolochene (10) exhibited selective activity against the fungal strains Aspergillus fumigatus ATCC46645 and Candida albicans ATCC64124 at 471 µM.

Structural and biosynthetic studies of botrycinereic acid, a new cryptic metabolite from the fungus Botrytis cinerea.

Chemical epigenetic manipulation of Botrytis cinerea strain B05.10 with the histone deacetylase inhibitor SAHA led to the isolation of a new cryptic metabolite, botrycinereic acid (22a). This compound was also overproduced by inactivating the stc2 gene, which encodes an unknown sesquiterpene cyclase. Its structure and absolute configuration were determined by extensive spectroscopic NMR and HRESIMS studies, and electronic circular dichroism calculations. Its biosynthesis was studied by feeding 2H and 13C isotopically labeled precursors to B. cinerea Δstc2 mutant. A detailed analysis of the labeling and coupling patterns into botrycinereic acid (22a) revealed that this compound derives from l-phenylalanine and l-leucine.

High incidence of stroke and mortality in pediatric critical care patients with COVID-19 in Peru.

INTRODUCTION: Pediatric critical care patients with COVID-19 treated in Peru have higher mortality than those previously reported from other countries. Pediatric providers have reported a high number of patients without comorbidities presenting with hemorrhagic strokes associated with COVID-19. We present a study analyzing the factors associated with mortality in this setting. METHODS: Prospective case-control study that included patients <17 years old admitted to a pediatric critical care unit with a positive test confirming COVID-19. The primary outcome was mortality. Fisher's exact test and the Mann-Whitney U test were used for the analysis. RESULTS: Forty-seven patients were admitted to critical care. The mortality of our study is 21.3%. The mortality of patients with neurological presentation was 45.5%, which was significantly higher than the mortality of acute COVID-19 (26.7%) and MIS-C (4.8%), p 0.18. Other risk factors for mortality in our cohort were strokes and comorbidities. Only one patient presenting with hemorrhagic stroke had an undiagnosed comorbidity. CONCLUSION: Cerebrovascular events associated with COVID-19 in pediatric patients, including infants, must be recognized as one of the more severe presentations of this infection in pediatric patients. IMPACT: Pediatric patients with COVID-19 can present with hemorrhagic and ischemic strokes on presentation. Neurological presentation in pediatric patients with COVID-19 has high mortality. Mortality of pediatric patients with COVID-19 is associated with comorbidities. Pediatric presentation and outcomes of COVID-19 in different regions can be novel to previously described.

Property-oriented basis sets for computation of atomization energies.

The SBO4-DZ(d,p)-3G basis sets introduced in a previous paper have been modified to improve their performance in the calculation of the atomization energies of organic molecules (pure or substituted hydrocarbons). The first step was to explore the possibility of improving those basis sets by adding a second D shell. The scale factor for an additional "D-3G" shell was first studied by minimizing the total energies. In a second step, the scale factor was calculated by optimizing atomization energies directly (instead total energies). This way the results obtained were very similar to those of the cc-pV5Z basis sets. Finally, we optimized simplified box orbital (SBO) basis sets for different methods obtaining optimal SBO basis sets for HF, DFTs, and MP2.

Bond reactivity indices approach analysis of the [2+2] cycloaddition of jatrophane skeleton diterpenoids from Euphorbia gaditana Coss to tetracyclic gaditanone.

The reaction mechanism of the intramolecular [2 + 2] cycloaddition from a jatrophane precursor to the gaditanane skeleton, an unprecedented 5/6/4/6-fused tetracyclic ring framework recently isolated from Euphorbia spp., was studied using the bond reactivity indices approach. Furthermore, six diterpenoids, including three undescribed jatrophanes isolated from E. gaditana Coss, were described. The structures of these compounds were deduced by a combination of 2D NMR spectroscopy and ECD data analysis.

On Electronegativity, Hardness, and Reactivity Descriptors: A New Property-Oriented Basis Set.

In this study, various ways of calculating electronegativity are analyzed after a brief summary of the evolution of this concept. We point out that some commonly used basis sets to calculate this parameter, such as 6-311G(d), provide results with an extraordinarily high margin of error. Therefore, a correction to the 6-311G(d) basis set is proposed that leads to calculations of electronegativity and hardness with a quality similar to those obtained with much broader basis sets, such as Aug-cc-pVQZ and Aug-cc-pV5Z. Since the calculation effort of the proposed basis is small, it can be applied to the accurate calculation of electronegativity and hardness in relatively large systems. It has also been tested in the calculation of reactivity indices and we have obtained results similar to those of the Aug-cc-pV5Z basis set. Finally, we have studied the densities corresponding to the frontier molecular orbitals in a representative sample set of molecules, using both the improved and other standard basis sets, and we have verified that the quality level of the proposed basis set is clearly better than that of standard basis sets with a similar calculation effort.

Software to obtain spatially localized functions from different radial functions.

We have developed an algorithm that enables simplified box orbital functions (SBO) to be obtained with optimized coefficients by fitting them to functions of many types. SBOs are a linear combination of radial functions useful in quantum chemistry calculations which can be spatially restricted (defined in [Formula: see text] interval, and zero for [Formula: see text]). The algorithm proposed makes it possible to obtain the optimal radius [Formula: see text] and the coefficients of the SBOs of any number of terms from the functions to be fitted, but also allows the user to define a particular radius r and calculate the coefficients of the combination of terms of the SBOs. SBOs have proved to be useful in the calculation of molecular properties, and can reduce the complexity of the integral calculations, especially in huge chemical systems such as atomic clusters. These types of functions are also adequate for studying confined systems such as molecules in solution or big chemical systems such as atomic clusters. In addition, while carrying out the examples presented in this study we have tested the suitability of SBO functions to calculate molecular reactivity, showing that the basis functions provide results as good as the basis sets typically used for this kind of calculations.

Introducing a new bond reactivity index: Philicities for natural bond orbitals.

In the present work, a new methodology defined for obtaining reactivity indices (philicities) is proposed. This is based on reactivity functions such as the Fukui function or the dual descriptor, and makes it possible to project the information from reactivity functions onto molecular orbitals, instead of onto the atoms of the molecule (atomic reactivity indices). The methodology focuses on the molecules' natural bond orbitals (bond reactivity indices) because these orbitals have the advantage of being localized, allowing the reaction site of an electrophile or nucleophile to be determined within a very precise molecular region. This methodology provides a "philicity" index for every NBO, and a representative set of molecules has been used to test the new definition. A new methodology has also been developed to compare the "finite difference" and the "frontier molecular orbital" approximations. To facilitate their use, the proposed methodology as well as the possibility of calculating the new indices have been implemented in a new version of UCA-FUKUI software. In addition, condensation schemes based on atomic populations of the "atoms in molecules" theory, the Hirshfeld population analysis, the approximation of Mulliken (with a minimal basis set) and electrostatic potential-derived charges have also been implemented, including the calculation of "bond reactivity indices" defined in previous studies. Graphical abstract A new methodology defined for obtaining bond reactivity indices (philicities) is proposed and makes it possible to project the information from reactivity functions onto molecular orbitals. The proposed methodology as well as the possibility of calculating the new indices have been implemented in a new version of UCA-FUKUI software. In addition, this version can use new atomic condensation schemes and new "utilities" have also been included in this second version.

Gaditanone, a Diterpenoid Based on an Unprecedented Carbon Skeleton Isolated from Euphorbia gaditana.

A novel diterpenoid, gaditanone (2), which possesses an unprecedented 5/6/4/6-fused gaditanane tetracyclic ring skeleton, and a new jatrophane (1) were isolated from the aerial parts of Euphorbia gaditana. The chemical structures and absolute configurations were determined by extensive spectroscopic NMR studies and ECD data analysis. A proposed biosynthetic pathway is presented for compound 2.

Micro-Raman Spectroscopy for the Determination of Local Temperature Increases in TiO2 Thin Films due to the Effect of Radiation.

This study applied a classic method involving Raman spectroscopy and the use of Stokes and anti-Stokes peaks to measure the temperature of TiO2 thin films found in dye-sensitized solar cells (DSSCs). In addition, three mathematical formulae were used and analyzed to estimate the increase in temperature generated solely by the effect of the radiation. The tests and calculations performed showed an increase in the temperature of the TiO2 film. That is, the films were heated by the radiation they were exposed to. A temperature increase of up to 30 K was detected for the sample with a single layer of TiO2, and over 40 K for the sample with three layers for the highest radiation powers used, and greater increases in temperature were observed in the thicker films.

A Study of Overheating of Thermostatically Controlled TiO2 Thin Films by Using Raman Spectroscopy.

In this study a classic Raman spectroscopy method is applied and the intensity ratio of Stokes and anti-Stokes peaks is used to measure the temperature of thermostatically controlled TiO2 thin films. In addition, three mathematical formulae are used and analyzed to estimate the temperature of the TiO2 thin films. Overheating of the samples above the thermostatically controlled temperature was observed while recording the Raman spectra, with a temperature increase of up to 30 K being detected. DFT-periodic calculations showed that the anatase (101) surface had a smaller band gap than bulk anatase. Thus, it can absorb the laser radiation with a wavelength of 532 nm that is used in the experimental setup. Part of the absorbed photon energy transfers into phonon energy, heating up the anatase phase, thus leading to the heating of the samples. Moreover, overheating of the samples indicates that the experimental method used in this study can lead to deviations in their real absolute temperature values.

DAMQT 2.1.0: A new version of the DAMQT package enabled with the topographical analysis of electron density and electrostatic potential in molecules.

DAMQT-2.1.0 is a new version of DAMQT package which includes topographical analysis of molecular electron density (MED) and molecular electrostatic potential (MESP), such as mapping of critical points (CPs), creating molecular graphs, and atomic basins. Mapping of CPs is assisted with algorithmic determination of Euler characteristic in order to provide a necessary condition for locating all possible CPs. Apart from the mapping of CPs and determination of molecular graphs, the construction of MESP-based atomic basin is a new and exclusive feature introduced in DAMQT-2.1.0. The GUI in DAMQT provides a user-friendly interface to run the code and visualize the final outputs. MPI libraries have been implemented for all the tasks to develop the parallel version of the software. Almost linear scaling of computational time is achieved with the increasing number of processors while performing various aspects of topography. A brief discussion of molecular graph and atomic basin is provided in the current article highlighting their chemical importance. Appropriate example sets have been presented for demonstrating the functions and efficiency of the code.

Introducing "UCA-FUKUI" software: reactivity-index calculations.

A new software (UCA-FUKUI) has been developed to facilitate the theoretical study of chemical reactivity. This program can calculate global parameters like hardness, softness, philicities, and Fukui condensed functions, and also local parameters from the condensed functions. To facilitate access to the program we have developed a very easy-to-use interface. We have tested the performance of the software by calculating the global and local reactivity indexes of a group of representative molecules. Finite difference and frontier molecular orbital methods were compared and their correlation tested. Finally, we have extended the analysis to a set of ligands of importance in coordination chemistry, and the results are compared with the exact calculation. As a general trend, our study shows the existence of a high correlation between global parameters, but a weaker correlation between local parameters.

Experimental and theoretical study of the electronic properties of Cu-doped anatase TiO2.

A good correlation was obtained between the electronic properties of Cu-doped anatase TiO2 by virtue of both physical chemistry characterization and theoretical calculations. Pure and Cu-doped TiO2 were synthesized. The composition, structural and electronic properties, and the band gap energy were obtained using several techniques. The method of synthesis used produces Cu-doped anatase TiO2, and XRD, XPS and Raman spectroscopy indicate that Cu atoms are incorporated in the structure by substitution of Ti atoms, generating a distortion of the structure and oxygen vacancies. In turn, the band gap energy of the synthesized samples decrease drastically with the Cu doping. Moreover, periodic density functional theory (DFT-periodic) calculations were carried out both to model the experimentally observed doped structures and to understand theoretically the experimental structures obtained, the formation of oxygen vacancies and the values of the band gap energy. From the analysis of density of states (DOS), projected density of states (PDOS) and the electron localization function (ELF) a decrease in the band gap is predicted upon increasing the Cu doping. Thus, the inclusion of Cu in the anatase structure implies a covalent character in the Cu-O interaction, which involves the appearance of new states in the valence band maximum with a narrowing in the band gap.

Ibuprofen loading in surfactant-templated silica: role of the solvent according to the polarizable continuum model.

Ibuprofen (an anti-inflammatory drug) has been loaded onto two different surfactant-templated silicas (SBA-15 and MCM-48). To evaluate the effect of the drug-solvent combination on the loading capacity of the silica, we have performed ibuprofen adsorption experiments using 10 different solvents; we have interpreted our experimental results assuming a chemical equilibrium between the ibuprofen adsorbed on the silica and that remaining in solution. To estimate the equilibrium constant for different solvents, we have calculated the free energy in solution for the ibuprofen molecule using the polarizable continuum model (PCM) to take the solvent into account. The results have been analyzed statistically to eliminate the effects of the dispersion of experimental data; results reveal a statistically significant (95-99%) linear relationship between the ibuprofen loading capacity and its free energy in solution calculated with the PCM solvation model. In addition, useful relationships between loading capacity and dielectric constant and molecular size of the solvents are established.