Hot Branching Dynamics in a Light‐Harvesting Iron Carbene Complex Revealed by Ultrafast X‐ray Emission Spectroscopy

Iron N‐heterocyclic carbene (NHC) complexes have received a great deal of attention recently because of their growing potential as light sensitizers or photocatalysts. We present a sub‐ps X‐ray spectroscopy study of an Fe^IINHC complex that identifies and quantifies the states involved in the deactivation cascade after light absorption. Excited molecules relax back to the ground state along two pathways: After population of a hot ³MLCT state, from the initially excited ¹MLCT state, 30 % of the molecules undergo ultrafast (150 fs) relaxation to the ³MC state, in competition with vibrational relaxation and cooling to the relaxed ³MLCT state. The relaxed ³MLCT state then decays much more slowly (7.6 ps) to the ³MC state. The ³MC state is rapidly (2.2 ps) deactivated to the ground state. The ⁵MC state is not involved in the deactivation pathway. The ultrafast partial deactivation of the ³MLCT state constitutes a loss channel from the point of view of photochemical efficiency and highlights the necessity to screen transition‐metal complexes for similar ultrafast decays to optimize photochemical performance.     

From a Medicinal Mushroom Blend a Direct Anticancer Effect on Triple-Negative Breast Cancer: A Preclinical Study on Lung Metastases

Bioactive metabolites isolated from medicinal mushrooms (MM) used as supportive treatment in conventional oncology have recently gained interest. Acting as anticancer agents, they interfere with tumor cells and microenvironment (TME), disturbing cancer development/progression. Nonetheless, their action mechanisms still need to be elucidated. Recently, using a 4T1 triple-negative mouse BC model, we demonstrated that supplementation with Micotherapy U-Care, a MM blend, produced a striking reduction of lung metastases density/number, paralleled by decreased inflammation and oxidative stress both in TME and metastases, together with QoL amelioration. We hypothesized that these effects could be due to either a direct anticancer effect and/or to a secondary/indirect impact of Micotherapy U-Care on systemic inflammation/immunomodulation. To address this question, we presently focused on apoptosis/proliferation, investigating specific molecules, i.e., PARP1, p53, BAX, Bcl2, and PCNA, whose critical role in BC is well recognized. We revealed that Micotherapy U-Care is effective to influence balance between cell death and proliferation, which appeared strictly interconnected and inversely related (p53/Bax vs. Bcl2/PARP1/PCNA expression trends). MM blend displayed a direct effect, with different efficacy extent on cancer cells and TME, forcing tumor cells to apoptosis. Yet again, this study supports the potential of MM extracts, as adjuvant supplement in the TNBC management.     

IRMPD Spectra of Protonated Hydroxybenzaldehydes: Evidence of Torsional Barriers in Carboxonium Ions

Protonation at the formyl oxygen atom of benzaldehydes leading to the formation of carboxonium ions yields two distinct isomers, depending on the relative orientation of the proton either cis or trans with respect to the hydrogen atom on the adjacent carbon. In this context, the IR multiple photon dissociation (IRMPD) spectra of protonated ortho, meta, and para-hydroxybenzaldehydes ( OH−BZH⁺ ), delivered into the gas phase by electrospray ionization of hydro-alcoholic solutions, are reported in the 3200–3700 cm⁻¹ spectral range. This range is characteristic of O−H stretching modes and thus able to differentiate cis and trans carboxonium isomers. Comparison between IRMPD spectra and DFT calculations at the B3LYP/6-311++G(2df2p) level suggests that for both p- OH−BZH⁺ and m- OH−BZH⁺ only cis conformers are present in the ion population analyzed. For o- OH−BZH⁺ , IRMPD spectroscopy points to a mixture comprising one trans and more than one cis conformers. The energy barrier for cis–trans isomerization calculated for each OH−BZH⁺ isomer is a measure of the degree of π-electron delocalization. Furthermore, IRMPD spectra of p- OH−BZH⁺ , m- OH−BZH⁺ and protonated phenol (this last used as reference) were recorded also in the fingerprint range. Both the observed C−O and O−H stretching vibrations appear to be a measure of π-electron delocalization in the ions.     

Investigation of anthropic effects connected with metal ions concentration, organic matter and grain size in Bormida river sediments

An investigation on the sediment composition and grain size was carried out along the Bormida river (Piedmont, Northern Italy). The samples were taken both in the riverbed and on its banks. Multivariate statistical exploratory methods permitted to identify possible sources of primary pollution. In particular, principal component analysis (PCA) showed that there are probably at least three anthropogenic main causes of pollution, one connected with Cr, Ni and Sn, the second with cadmium and the last one with mercury. Some correlations were found between heavy metal ion concentrations and organic matter and/or the sediment grain size. Differences between the samples collected in the riverbed and on the banks were identified and the relationships between the principal components and the distance of the samples from the riverbed and from the hot spot represented by the ACNA industrial site were also analyzed.     

Benefit of modulated maskers for speech recognition by younger and older adults with normal hearing

To assess age-related differences in benefit from masker modulation, younger and older adults with normal hearing but not identical audiograms listened to nonsense syllables in each of two maskers: (1) a steady-state noise shaped to match the long-term spectrum of the speech, and (2) this same noise modulated by a 10-Hz square wave, resulting in an interrupted noise. An additional low-level broadband noise was always present which was shaped to produce equivalent masked thresholds for all subjects. This minimized differences in speech audibility due to differences in quiet thresholds among subjects. An additional goal was to determine if age-related differences in benefit from modulation could be explained by differences in thresholds measured in simultaneous and forward maskers. Accordingly, thresholds for 350-ms pure tones were measured in quiet and in each masker; thresholds for 20-ms signals in forward and simultaneous masking were also measured at selected signal frequencies. To determine if benefit from modulated maskers varied with masker spectrum and to provide a comparison with previous studies, a subgroup of younger subjects also listened in steady-state and interrupted noise that was not spectrally shaped. Articulation index (AI) values were computed and speech-recognition scores were predicted for steady-state and interrupted noise; predicted benefit from modulation was also determined. Masked thresholds of older subjects were slightly higher than those of younger subjects; larger age-related threshold differences were observed for short-duration than for long-duration signals. In steady-state noise, speech recognition for older subjects was poorer than for younger subjects, which was partially attributable to older subjects' slightly higher thresholds in these maskers. In interrupted noise, although predicted benefit was larger for older than younger subjects, scores improved more for younger than for older subjects, particularly at the higher noise level. This may be related to age-related increases in thresholds in steady-state noise and in forward masking, especially at higher frequencies. Benefit of interrupted maskers was larger for unshaped than for speech-shaped noise, consistent with AI predictions.     

Scientific World Building on the Edge of Chaos: High School Students' Beliefs About Mathematics and Science

This study investigated high school students' beliefs about mathematics and science during a four week summer residential mathematics and science program. Beliefs about mathematical and scientific truths, the value and importance of mathematics and science inquiry, gender equity and ability with respect to pursuit of mathematics and science careers, the relationship between mathematics and technology, and the role of science in society were examined. Habermasian ways of knowing were used to categorize student beliefs and determine student world views. Implications of this study include suggested changes in the organizational dynamics of schooling to better prepare our students for surviving in the complexity of the 21st century and reducing dissonance between the “classical” educational viewpoints and the “chaotic” world.     

Polarity effects on ZnO films grown along the nonpolar [1120] direction

The surface electrical properties of ZnO thin films grown along the nonpolar [1120] direction have been investigated by Kelvin probe microscopy on a nanometer scale. Two different charge domains, with a 75 meV work function difference, coexist within the ZnO surface, which is covered by rhombohedral pyramids whose sidewalls are shown to be {1011}-type planes. The presence and relative orientation of the two kinds of charge domains are explained in terms of the atomic arrangement at the {1011} polar surfaces.