Photoinduced Absorption Spectroscopy of Poly-3-Alkylthiophenes

1992 ◽  
Vol 247 ◽  
Author(s):  
C. Botta ◽  
S. Luzzati ◽  
A. Bolognesi ◽  
R. Tubino ◽  
A. Borghesi
Keyword(s):  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Laser Intensity ◽  
Electronic States ◽  
Chain Mechanism ◽  
Photoinduced Absorption ◽  
Polymer Aggregates ◽  
Cast Films ◽  
Solution Cast

ABSTRACTWe report a study of the near infrared photoinduced absorption of a series of poly -3-decylthiophene with different supermolecular organization as solution cast films, good solvent and aggregated bad solvent solutions.Photoinduced subgap electronic states are detected both in the solid and in solutions independently from the presence of polymer aggregates. The study of the photoinduced activity Δ/T on the laser intensity I indicate a I0.6 dependence for the films and a I0.95 dependence for the solutions. This is the evidence that the photoinduced states are generated in the solid via an inter-chain mechanism while in the solution via an intra-chain mechanism.A possible role of the solvent into the photoexcitation pathway is discussed.

scholarly journals Probing P25 TiO2 Photocatalysis Using Photoinduced Absorption Spectroscopy (PIAS)

2021 ◽  
Author(s):  
Andrew Mills ◽  
Christopher O'Rourke
Keyword(s):  
Absorption Spectroscopy ◽  
Photoinduced Absorption ◽  
Tio2 Photocatalysis ◽  
Mesoporous Film ◽  
First Time ◽  
Film Form

Photoinduced absorption spectroscopy, PIAS, is used for the first time to probe the kinetics exhibited by the most commonly employed powder photocatalyst, P25 TiO2, in mesoporous film form, in the...

scholarly journals Improvement of obesity-associated disorders by a small-molecule drug targeting mitochondria of adipose tissue macrophages

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yawei Wang ◽  
Binlin Tang ◽  
Lei Long ◽  
Peng Luo ◽  
Wei Xiang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Oxidative Phosphorylation ◽  
Near Infrared ◽  
Mitochondrial Metabolism ◽  
Diet Induced Obesity ◽  
Adipose Tissue Macrophages ◽  
Inflammatory Activation ◽  
Treatment Of Obesity ◽  
Pharmaceutical Agents

AbstractPro-inflammatory activation of adipose tissue macrophages (ATMs) is causally linked to obesity and obesity-associated disorders. A number of studies have demonstrated the crucial role of mitochondrial metabolism in macrophage activation. However, there is a lack of pharmaceutical agents to target the mitochondrial metabolism of ATMs for the treatment of obesity-related diseases. Here, we characterize a near-infrared fluorophore (IR-61) that preferentially accumulates in the mitochondria of ATMs and has a therapeutic effect on diet-induced obesity as well as obesity-associated insulin resistance and fatty liver. IR-61 inhibits the classical activation of ATMs by increasing mitochondrial complex levels and oxidative phosphorylation via the ROS/Akt/Acly pathway. Taken together, our findings indicate that specific enhancement of ATMs oxidative phosphorylation improves chronic inflammation and obesity-related disorders. IR-61 might be an anti-inflammatory agent useful for the treatment of obesity-related diseases by targeting the mitochondria of ATMs.

Optical Absorption Spectroscopy of DNA-Wrapped HiPco Carbon Nanotubes

2019 ◽  
Vol 943 ◽  
pp. 95-99
Author(s):  
Li Jun Wang ◽  
Kazuo Umemura
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Optical Characterization ◽  
Optical Absorption Spectroscopy ◽  
Double Stranded Dna

Optical absorption spectroscopy provides evidence for individually dispersed carbon nanotubes. A common method to disperse SWCNTs into aqueous solution is to sonicate the mixture in the presence of a double-stranded DNA (dsDNA). In this paper, optical characterization of dsDNA-wrapped HiPco carbon nanotubes (dsDNA-SWCNT) was carried out using near infrared (NIR) spectroscopy and photoluminescence (PL) experiments. The findings suggest that SWCNT dispersion is very good in the environment of DNA existing. Additionally, its dispersion depends on dsDNA concentration.

scholarly journals Analytical Theory of Attosecond Transient Absorption Spectroscopy of Perturbatively Dressed Systems

2019 ◽  
Vol 9 (7) ◽  
pp. 1350
Author(s):  
Daria Kolbasova ◽  
Robin Santra
Keyword(s):  
Perturbation Theory ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Electronic States ◽  
Theoretical Description ◽  
Transient Absorption Spectroscopy ◽  
Electron Dynamics ◽  
Optical Pulses ◽  
Absorption Signal ◽  
Level Model

A theoretical description of attosecond transient absorption spectroscopy for temporally and spatially overlapping XUV and optical pulses is developed, explaining the signals one can obtain in such an experiment. To this end, we employ a two-stage approach based on perturbation theory, which allows us to give an analytical expression for the transient absorption signal. We focus on the situation in which the attosecond XUV pulse is used to create a coherent superposition of electronic states. As we explain, the resulting dynamics can be detected in the spectrum of the transmitted XUV pulse by manipulating the electronic wave packet using a carrier-envelope-phase-stabilized optical dressing pulse. In addition to coherent electron dynamics triggered by the attosecond pulse, the transmitted XUV spectrum encodes information on electronic states made accessible by the optical dressing pulse. We illustrate these concepts through calculations performed for a few-level model.

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