Spectroscopy Journal

13 pages, 3247 KiB

Open AccessArticle

Effect of Alkaline Salts on Pyrolyzed Solid Wastes in Used Edible Oils: An Attenuated Total Reflectance Analysis of Surface Compounds as a Function of the Temperature

by Francisca Romero-Sarria, Concepción Real, José Manuel Córdoba, María Carmen Hidalgo and María Dolores Alcalá

Spectrosc. J. 2023, 1(2), 98-110; https://doi.org/10.3390/spectroscj1020009 - 13 Sep 2023

Viewed by 736

Abstract

Biochars obtained via the pyrolysis of biomass are very attractive materials from the point of view of their applications and play key roles in the current energy context. The characterization of these carbonaceous materials is crucial to determine their field of application. In this work, the pyrolysis of a non-conventional biomass (solid wastes in used edible oils) was investigated. The obtained biochars were characterized using conventional techniques (TG, XRD, and SEM-EDX), and a deep analysis via ATR-FTIR was performed. This spectroscopic technique, which is a rapid and powerful tool that is well adapted to study carbon-based materials, was employed to determine the effect of temperature on the nature of functional groups on the surface. Moreover, the water washing of the raw sample (containing important quantities of inorganic salts) before pyrolysis evidenced that the inorganic salts act as catalysts in the biomass degradation and influence the degree of condensation (DOC) of PAH. Moreover, it was observed that these salts contribute to the retention of oxygenated compounds on the surface of the solid. Full article

(This article belongs to the Special Issue Feature Papers in Spectroscopy Journal)

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12 pages, 1266 KiB

Open AccessArticle

Narrow-Linewidth Pr:YLF Laser for High-Resolution Raman Trace Gas Spectroscopy

by Charuka Muktha Arachchige and Andreas Muller

Spectrosc. J. 2023, 1(2), 86-97; https://doi.org/10.3390/spectroscj1020008 - 23 Aug 2023

Viewed by 1201

Abstract

Spontaneous Raman gas spectroscopy, which stands out as a versatile chemical identification tool, typically relies on frequency-doubled infrared laser sources to deliver the high power and narrow linewidth needed to achieve chemical detection at trace concentrations. The relatively low efficiency and high complexity of these lasers, however, can make them challenging to integrate into field-deployable instruments. Additionally, the frequency doubling prevents the utilization of circulating laser power for Raman enhancement. A diode-pumped Pr:YLF laser was investigated as an alternative narrow-band light source that could potentially realize a more portable Raman scattering system. When operated with an intracavity etalon, the laser realized a linewidth of 0.5 cm

^{- 1}

with a green output power of 0.37 W and circulating power of 16 W when pumped with 3.1 W from a blue diode laser. Trace detection at atmospheric pressure with a high degree of spectral discrimination was demonstrated by resolving overlapping N

_{2}

/CO and CO

_{2}

_{2}

O Raman bands in air. Full article

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14 pages, 3347 KiB

Open AccessArticle

Dielectric Stability of Triton X-100-Based Tissue-Mimicking Materials for Microwave Imaging

by Mariana Relva and Susana Devesa

Spectrosc. J. 2023, 1(2), 72-85; https://doi.org/10.3390/spectroscj1020007 - 03 Aug 2023

Viewed by 1084

Abstract

Microwave imaging is an emerging technology, and has been proposed for various applications, namely as an alternative diagnostic technology. Microwave imaging explores the dielectric contrast of target tissues, enabling diagnosis based on the differences in dielectric properties between healthy and diseased tissues, with low cost, portability and non-ionizing radiation as its main advantages, constituting an alternative to various imaging technologies for diagnosing and monitoring. Before clinical trials of microwave imaging devices for the study of dielectric properties, phantoms are used, mimicking the materials of tissues and simulating the electric properties of human tissues, for device validation. The purpose of this work was to prepare and perform dielectric characterization of mimicking materials for the development of an anthropomorphic phantom of the human ankle with realistic dielectric and anatomic properties. The biological tissues targeted in this investigation were the skin, muscle, cortical bone, trabecular bone and fat, with the mimicking materials prepared using Triton X-100, sodium chloride and distilled water. The dielectric characterization was performed using a coaxial probe, operating at frequencies between 0.5 and 4.0 GHz. Since the stability of the dielectric properties of mimicking materials is one of their main properties, the dielectric characterization was repeated after 15 and 35 days. Full article

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7 pages, 2588 KiB

Open AccessCommunication

Light-Induced Condensates Show Accumulation-Prone and Less Dynamic Properties in the Nucleus Compared to the Cytoplasm

by Yuta Hamada and Akira Kitamura

Spectrosc. J. 2023, 1(2), 65-71; https://doi.org/10.3390/spectroscj1020006 - 10 Jul 2023

Viewed by 908

Abstract

Biomolecular condensates, including membraneless organelles, are ubiquitously observed in subcellular compartments. However, the accumulation and dynamic properties of arbitrarily induced condensates remain elusive. Here, we show the size, amount, and dynamic properties of subcellular condensates using various fluorescence spectroscopic imaging analyses. Spatial image correlation spectroscopy showed that the size of blue-light-induced condensates of cryptochrome 2-derived oligomerization tag (CRY2olig) tagged with a red fluorescent protein in the nucleus was not different from that in the cytoplasm. Fluorescence intensity measurements showed that the condensates in the nucleus were more prone to accumulation than those in the cytoplasm. Single-particle tracking analysis showed that the condensates in the nucleus are predisposed to have stationary dynamics compared to those in the cytoplasm. Therefore, the subcellular compartment may, in part, affect the characteristics of self-recruitment of biomolecules in the condensates and their movement property. Full article

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Spectrosc. J., Volume 1, Issue 2 (September 2023) – 4 articles

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