Hydration Shells of DPPC Liposomes from the Point of View of Terahertz Time-Domain Spectroscopy

 Penkov, Nikita V., Valery A. Yashin, and Konstantin N. Belosludtsev. "Hydration Shells of DPPC Liposomes from the Point of View of Terahertz Time-Domain Spectroscopy." Applied Spectroscopy (2020): 0003702820949285.

Abstract

Analysis of structural and dynamic properties of water in suspensions of liposomes composed from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in three phase states (gel, rippled gel, liquid crystalline phase) by means of terahertz time-domain spectroscopy in 0.3–3.3 THz range was conducted in the current work. Fraction of free water molecules in DPPC liposome suspension was shown to decrease with temperature (compared to the analogous aqueous solution without liposomes), and intermolecular water binding was enhanced. The most crucial changes occur during gel-rippled gel phase transition (pretransition): at temperatures below pretransition point, liposomes alleviate water binding degree, while at temperatures above the transition point, they enhance water binding. This study has demonstrated the high information content of the terahertz time-domain spectroscopy method for exploring the hydration properties of phospholipids in water.

… spectra and refractive index spectra of the substance under investigation were measured at the same time with the help of a TPS Spectra 3000 spectrometer (Teraview, UK) in the range of wavenumber 10–110 cm –1 with the … 

Effect of particle size and deformation behaviour on water ingress into tablets

Skelbæk-Pedersen, Anne Linnet, Mohammed Al-Sharabi, Thomas Kvistgaard Vilhelmsen, Jukka Rantanen, and J. Axel Zeitler. "Effect of particle size and deformation behaviour on water ingress into tablets." International Journal of Pharmaceutics 587 (2020): 119645.

Abstract

Drug release performance of tablets is often highly dependent on disintegration, and water ingress is typically the rate-limiting step of the disintegration process. Water ingress into tablets is known to be highly influenced by the microstructure of the tablet, particularly tablet porosity. Initial particle size distribution of the formulation and the predominant powder deformation behaviour during compression are expected to impact such microstructure, making both factors important to investigate in relation to water ingress into tablets. Two size fractions (<125 and 355–500 µm) of plastically deforming microcrystalline cellulose (MCC) and fragmenting di-calcium phosphate (DCP) were compressed into tablets with porosities ranging from 5 to 30% (with 5% increments). The total porosity of the tablets was measured using terahertz time-domain spectroscopy and liquid transport into these tablets was quantified using a flow cell coupled to terahertz pulsed imaging. It was found that tablets compressed from large MCC particles resulted in slower water ingress compared to tablets prepared from small MCC particles. In contrast, no difference in liquid transport kinetics was observed for tablets prepared across both size fractions of DCP particles. These results highlight the complex interplay between material characteristics, the process induced microstructure, and the liquid transport process that ultimately determines the drug release performance of the tablets.

… Terahertz time-domain spectroscopy (THz-TDS) measurements were acquired in a transmission setup using a Terapulse 4000 spectrometer (Teraview Ltd., Cambridge, UK) (n = 3). The chamber was purged with dry nitrogen gas …

For full paper see https://www.sciencedirect.com/science/article/abs/pii/S0378517320306293

Terahertz imaging aids in art restoration

 

TeraView is pleased to announce that it has begun a collaboration with the Russian Museum’s Technology Research Department in St Petersburg, Russia aimed at demonstrating the power and capabilities of terahertz imaging in art restoration. TeraView is the leading supplier of terahertz systems to support a range of applications. Recently, the use of terahertz imaging in art restoration has been demonstrated by different museums and other institutions across the world. In some paintings and other works of art, terahertz imaging is able to detect the sequence and thickness of the different layers of paint, each of which can be imaged separately, effectively producing a 3D image of the artwork. Terahertz imaging can thus help reveal the artist’s technique, as well as authenticate paintings in some instances where the identity of the artist is in question. Additionally, terahertz imaging can assist art conservation and restoration decisions by providing information on cracks, delamination and defects buried below the surface and not visible to the naked eye or readily accessible with other techniques. The full press release is available to view here.

Terahertz Coating thickness analysis

Designed for the coatings industry, the TeraCota sensor can determine the individual thickness of multiple paint layers on both metallic and non-metallic substrates and offers significant benefits over existing techniques.

The sensor is non-contact, suitable for working on curved surfaces and capable of performing horizontal and vertical line scans.

For more information on the TeraCota system visit TeraView's web site at www.teraview.com #terahertz

Optical constants of CuO and ZnO particles in the terahertz frequency range

 Calvo-de la Rosa, Jaume, Alexandre Locquet, Denis Bouscaud, Sophie Berveiller, and D. S. Citrin. "Optical constants of CuO and ZnO particles in the terahertz frequency range." Ceramics International (2020).

Abstract

The optical constants (complex dielectric function) of CuO and ZnO particles in polyethylene pellets are measured by terahertz time-domain spectroscopy. The determination of the dielectric properties of these materials is of interest for energy-storage applications, for instance. Maxwell-Garnett theory is used to extract the contribution to the frequency-dependent optical constants of the oxide powders. The validity of the assumptions of Maxwell-Garnett theory are experimentally verified and self-consistency of the results of the model confirmed. On this basis, experimental complex permittivity values for isotropic CuO and ZnO oxide powders are reported in the 100 GHz-3 THz range.

for full paper see https://www.sciencedirect.com/science/article/pii/S0272884220318502

"THz transmission data through the pellets were obtained using a TeraView TPS Spectra 3000 in transmission mode. The experimental bandwidth (power spectrum of "