Efficient Upconversion by Highly Water-Soluble Cationic Sensitizer and Emitter in Aqueous Solutions with DNA

Highly water-soluble cationic palladium porphyrin as a sensitizer and 9,10-bis­(4-trimethylammoniumphenyl)­anthracene as an emitter were newly synthesized. They were shown to be bound and immobilized in DNA double helix assembly from absorption, fluorescence, phosphorescence, and circular dichroism spectra. Upon excitation at 532 nm in deaerated aqueous solutions, they showed weak blue upconversion fluorescence, the efficiency of which increased dramatically in the presence of DNA. The threshold power density between the second-order and first-order power dependence of upconversion fluorescence decreased to less than a half upon addition of DNA. The emitter triplet lifetime estimated from time dependences of upconversion fluorescence at low power ns pulsed laser was found to considerably increase in the presence of DNA. From these results, DNA was concluded to work effectively in concentrating both sensitizer and emitter and in migrating excited triplet states, resulting in efficient upconversion

Alexithymia characteristics are associated with salience network activity in healthy participants: an arterial spin labeling study

Abstract Background Alexithymia, a personality trait characterized by difficulties in identifying and expressing their emotions despite having a range of emotional experiences, can impact individuals’ stress coping mechanisms. While many studies have investigated brain functions associated with specific tasks in relation to emotion processing, research focusing on resting-state brain functions has been limited. Thus, the aim of this study was to investigate the relationship between alexithymia and brain function by analyzing arterial spin labeling (ASL) data obtained during the resting state. Methods A brain structural and functional imaging study was conducted on 42 healthy adult men and women using ASL and the 20-item Toronto Alexithymia Scale (TAS-20) questionnaire survey. Cerebral blood flow and functional connectivity values were calculated for regions of interest in the default mode network, saliency network, and central executive network from the ASL data. Correlation analysis was performed with TAS20 scores, and partial correlation analysis was conducted to control for anxiety and depression. Results The functional connectivity analysis revealed a negative correlation between the functional connectivity of the right insular cortex and left anterior cingulate cortex and the total score of TAS, as well as difficulty identifying feelings and difficulty describing feeling subscores, indicating that the higher the scores, the weaker the functional connectivity between these regions (T = -3.830, p = 0.0013, R = -0.5180). This correlation remained significant even after controlling for anxiety and depression using partial correlation analysis. Conclusion The present study revealed differences in the activity of the Saliency Network at rest as measured by ASL, which were independent of anxiety and depression, and varied depending on the severity of alexithymia. This functional change may underlie the neural basis of decreased emotional processing observed in alexithymia. These findings may contribute to the elucidation of the neural mechanisms of alexithymia, which can lead to social impairments, and suggest the usefulness of ASL measurement as a biomarker of alexithymia

Layered Double Hydroxide Nanoparticles/Microparticles (Mg/Al = 2) as Adsorbents for Temperature Swing Adsorption: Effect of Particle Size on CO₂ Gas Evolution Behavior

Mg–Al layered double hydroxide (LDH, Mg/Al ≈ 2) nanoparticles/microparticles with systematically controlled sizes were prepared using a hydrothermal method, and their performance as CO2 adsorbents for temperature swing adsorption (TSA) cycling was investigated. During continuous heating, gas evolution occurred in three distinct steps for all samples. During the second step of the multistep structural transformations (i.e., partial dehydroxylation of the layers followed by the coordination of carbonate ions to the metal ions), relatively large amounts of CO2 were evolved without the collapse of the layered crystal structure, whereas most of the interlayer CO32– ions were retained in the interlayer spaces. The amount of CO2 evolution increased as the particle size decreased. Subsequently, the amount of CO2 desorption was measured over repeated TSA cycles in the temperature range 463–603 K. All samples exhibited considerable CO2 desorption capacities, wherein water vapor enhanced the performance. In situ Fourier transform infrared spectroscopy revealed that the adsorption–desorption cycles were almost reversible. A slight change in the interlayer distance detected by in situ X-ray diffraction suggested that the insertion and removal of some carbonate species partly occurred in the interlayer spaces of the LDHs. The present study indicates the potential of LDH nanoparticles/microparticles for TSA adsorbents