Raman spectroscopy (RS) is a powerful, noninvasive optical technique able to detect vibrational modes of chemical bonds. The high chemical specificity due to its fingerprinting character and the minimal requests for sample preparation have rendered it nowadays very popular in the analysis of biosystems for diagnostic purposes. In this paper, we first discuss the main advantages of spontaneous RS by describing the study of a single protozoan (<i>Acanthamoeba</i>), which plays an important role in a severe ophthalmological disease (<i>Acanthamoeba</i> keratitis). Later on, we point out that the weak signals that originated from Raman scattering do not allow probing optically thin samples, such as cellular membrane. Experimental approaches able to overcome this drawback are based on the use of metallic nanostructures, which lead to a huge amplification of the Raman yields thanks to the excitation of localized surface plasmon resonances. Surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS) are examples of such innovative techniques, in which metallic nanostructures are assembled on a flat surface or on the tip of a scanning probe microscope, respectively. Herein, we provide a couple of examples (red blood cells and bacterial spores) aimed at studying cell membranes with these techniques.

Giulia Rusciano

Gianluigi Zito

Giuseppe Pesce

Antonio Sasso

Cell Imaging by Spontaneous and Amplified Raman Spectroscopies

Coal spontaneous combustion (CSC) generally induces fire disasters in underground mines, thus causing serious casualties, environmental pollution, and property loss around the world. By using six P-containing additives to process three typical coal samples, this study investigated the variations of the self-ignition characteristics of the coal samples before and after treatment. The analysis was performed by combining thermogravimetric analysis/differential scanning calorimetry (TG/DSC) Fourier transform infrared spectrometer (FTIR) and low temperature oxidation. Experimental results showed that P-containing inhibitors could effectively restrain the heat emitted in the combustion of coal samples and therefore the ignition temperature of the coal samples was delayed at varying degrees. The combustion rate of the coal samples was reduced as well. At the temperatures ranging from 50&#xb0;C to 150&#xb0;C, the activation energy of the coal samples after the treatment was found to increase, which indicated that the coal samples were more difficult to be oxidized. After being treated with phosphorus flame retardants (PFRs), the content of several active groups represented by the C-O structure in the three coal samples was proved to be obviously changed. This suggested that PFRs could significantly inhibit the content of CO generated by the low temperature oxidation of coal, and the flame-retardant efficiency grew with the increasing temperature. At 200&#xb0;C, the maximal inhibition efficiency reached approximately 85&#x25;.

Yibo Tang

Inhibition Effect of Phosphorus Flame Retardants on the Fire Disasters Induced by Spontaneous Combustion of Coal

Mn<sup>2+</sup> ion doping is used as an electron paramagnetic resonance (EPR) probe to investigate the influence of low-coordination structural defects such as step edges at the surface of terraced (001) MgO nanoparticles on the electronic properties. Beside the well-known hyperfine sextet of Mn<sup>2+</sup> ions in the cubic crystal field of MgO, an additional EPR feature with a striking nonmonotonous temperature dependent shift of the <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.42943pt" id="M1" height="9.39034pt" version="1.1" viewBox="-0.0498162 -5.96091 7.52435 9.39034" width="7.52435pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-104" d="M546 430L539 434C529 434 505 438 495 440C473 444 450 448 430 448C352 448 265 412 213 366C145 306 96 203 96 103C96 22 135 -12 160 -12C190 -12 238 14 262 32C310 68 368 120 411 184H413C403 117 396 75 384 21C353 -118 325 -158 291 -184C270 -200 241 -205 208 -205C133 -205 90 -164 74 -110C70 -98 58 -100 49 -107C34 -119 23 -140 23 -155C23 -190 74 -261 166 -261C219 -261 280 -233 314 -208C383 -157 446 -79 470 81C491 223 529 388 546 430ZM456 386C452 357 433 283 420 252C402 216 366 174 325 129C288 88 239 56 212 56C192 56 182 77 182 120C182 165 199 242 226 292C256 348 281 377 311 389C327 395 353 402 375 402C408 402 436 394 456 386Z"/></g></svg>-factor is observed in terraced nanoparticles in the temperature range from 4 K to room temperature. By linking the difference in the temperature dependence of the Mn<sup>2+</sup> sextet intensity in cubic and terraced nanoparticles with the possible s-d exchange shift and enhanced Zeeman splitting we conclude that the novel EPR feature originates from the loosely trapped charge-compensating carriers at the abundant structural defects at the surface of terraced nanoparticles due to their exchange interaction with neighboring Mn<sup>2+</sup> ions. 

Peter V. Pikhitsa

Sukbyung Chae

Seungha Shin

Mansoo Choi

A Low-Field Temperature Dependent EPR Signal in Terraced MgO:Mn<sup>2+</sup> Nanoparticles: An Enhanced Zeeman Splitting in the Wide-Bandgap Oxide

The breakup regime in ethanol diffusion flame under different conditions was studied by the high speed camera system combined with the UV camera system. Spray angle and Weber number (We) were used to represent the change of breakup regime. With the increases of spray angle and We, the breakup mode changes from the Rayleigh-type breakup regime to the superpulsating regime. The reaction area and intensity of ethanol flames under different breakup regimes could be discussed by the <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2455997pt" id="M1" height="10.3481pt" version="1.1" viewBox="-0.0498162 -10.1025 25.804 10.3481" width="25.804pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g121-77" d="M381 665C170 665 44 498 44 318C44 125 188 -15 369 -15C552 -15 703 117 703 333C703 534 550 665 381 665ZM359 629C491 629 601 517 601 306C601 114 502 21 390 21C249 21 146 158 146 346S248 629 359 629Z"/></g><g transform="matrix(.013,0,0,-0.013,9.594,0)"><path id="g121-70" d="M729 650H468V622C546 615 554 610 554 527V365H213V527C213 610 221 616 297 622V650H38V622C120 616 128 611 128 527V123C128 39 120 34 40 28V0H303V28C221 34 213 40 213 123V322H554V123C554 39 546 34 460 28V0H728V28C647 34 639 39 639 123V527C639 610 647 615 729 622V650Z"/></g><g transform="matrix(.0091,0,0,-0.0091,19.625,-5.741)"><path id="g50-43" d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 486 347 485 366C470 376 444 381 422 380C389 338 368 319 321 288C323 345 329 372 349 422C339 442 322 461 305 470C289 461 271 442 262 422C281 372 287 345 290 288C243 319 222 338 189 380C167 381 142 376 125 366C125 347 133 322 145 304C198 296 225 288 275 262C225 236 198 227 145 220C133 201 125 177 126 158C141 148 167 143 189 144C222 186 243 205 290 236C288 179 282 152 262 102C272 82 289 63 306 54C322 63 340 82 350 102C330 152 324 179 321 236C368 205 390 186 422 144C444 143 470 148 486 158Z"/></g></svg> distribution. From Rayleigh-type breakup regime to superpulsating breakup regime, the <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2455997pt" id="M2" height="10.3481pt" version="1.1" viewBox="-0.0498162 -10.1025 25.804 10.3481" width="25.804pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g121-77"/></g><g transform="matrix(.013,0,0,-0.013,9.594,0)"><use xlink:href="#g121-70"/></g><g transform="matrix(.0091,0,0,-0.0091,19.625,-5.741)"><use xlink:href="#g50-43"/></g></svg> distribution increased and the oxidation-reduction reaction area expanded. At the condition of superpulsating breakup mode, the intensity of <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2455997pt" id="M3" height="10.3481pt" version="1.1" viewBox="-0.0498162 -10.1025 25.804 10.3481" width="25.804pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g121-77"/></g><g transform="matrix(.013,0,0,-0.013,9.594,0)"><use xlink:href="#g121-70"/></g><g transform="matrix(.0091,0,0,-0.0091,19.625,-5.741)"><use xlink:href="#g50-43"/></g></svg> was significantly higher than that of other modes. The flame luminous length can be obtained by the <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2455997pt" id="M4" height="10.3481pt" version="1.1" viewBox="-0.0498162 -10.1025 25.804 10.3481" width="25.804pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g121-77"/></g><g transform="matrix(.013,0,0,-0.013,9.594,0)"><use xlink:href="#g121-70"/></g><g transform="matrix(.0091,0,0,-0.0091,19.625,-5.741)"><use xlink:href="#g50-43"/></g></svg> emission, and <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2455997pt" id="M5" height="10.3481pt" version="1.1" viewBox="-0.0498162 -10.1025 25.804 10.3481" width="25.804pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g121-77"/></g><g transform="matrix(.013,0,0,-0.013,9.594,0)"><use xlink:href="#g121-70"/></g><g transform="matrix(.0091,0,0,-0.0091,19.625,-5.741)"><use xlink:href="#g50-43"/></g></svg> distribution reflects the structure of flame. When the breakup regime changes from the fiber-type breakup regime to the superpulsating regime, the flame luminous length increases suddenly.

Qing Zhang

Xudong Song

Qinghua Guo

Yan Gong

Chonghe Hu

Guangsuo Yu

Experimental Study on the Atomization and Chemiluminescence Characteristics of Ethanol Flame

A new, simple, and sensitive spectrometric method was developed for hydroquinone (HQ) determination in the presence of other depigmenting agents (kojic acid (KA), glycolic acid (GA), and ascorbic acid (AA)), commonly introduced in skin lightening products. The method is based on the oxidation of the depigmenting agents by potassium dichromate in sulfuric acid medium and subsequent measurement of the amplitude of the first-order derivative absorption spectrum at 268&#x2009;nm. By applying the zero-crossing method, at this wavelength, the oxidation products of KA, AA, and GA do not interfere in the indirect determination of HQ. Beer&#x2019;s law was obeyed in the range of 0.22&#x2013;22&#x2009;<i>&#x3bc;</i>g&#xB7;mL<sup>&#x2212;1</sup> HQ, with a detection limit of 0.07&#x2009;<i>&#x3bc;</i>g&#xB7;mL<sup>&#x2212;1</sup>. The developed method was applied with good results for the first time to the rapid determination of HQ in binary, ternary, and quaternary mixtures, thus proving that it could represent an effective tool for various skin lightening products analyses.

Zenovia Moldovan

Dana Elena Popa

Iulia Gabriela David

Mihaela Buleandra

Irinel Adriana Badea

A Derivative Spectrometric Method for Hydroquinone Determination in the Presence of Kojic Acid, Glycolic Acid, and Ascorbic Acid

Thioflavin T (ThT) is a widely used fluorescent probe of amyloid fibrils, which accompanies many serious neurodegenerative and other diseases. Until recently, examinations of processes of amyloid fibril formation in vitro were conducted in solutions whose properties were significantly different from those found inside the densely packed cells. Such crowded cellular milieu is typically simulated in vitro using concentrated solutions of inert polymers, which do not usually interact with proteins. However, these crowding agents can have a direct effect on the ThT molecule, and this effect must be taken into account. We examined the influence of PEG-400, PEG-12000, and Dextran-70 on the photophysical properties of ThT. It was shown that these crowding agents caused the red shift of the absorption, fluorescence excitation, and fluorescence spectra of ThT. Under these conditions, the increases of the molar extinction coefficient, fluorescence quantum yield, and excitation lifetime of ThT are also observed. However, these changes are significantly less pronounced than those observed for ThT bound to fibrils. It is concluded that, despite some effects of crowding agents on intrinsic fluorescent properties of ThT, this dye can be used as a probe of structure and formation of amyloid fibrils in crowded milieu in vitro.

Natalia P. Rodina

Maksim I. Sulatsky

Anna I. Sulatskaya

Irina M. Kuznetsova

Vladimir N. Uversky

Konstantin K. Turoverov

Photophysical Properties of Fluorescent Probe Thioflavin T in Crowded Milieu

Part of an indestructible component of any orthodox church, the Imperial Gates represent an important symbol in our cultural heritage. But in many cases the Imperial Gates from the wooden churches were damaged. In order to preserve and restore them, the scientific investigations of the Imperial Gate belonging to Nicula Monastery wooden church were performed by employing nondestructive and destructive methods. The wood essence was established, with its &#x201c;health&#x201d; status being investigated by FTIR (Fourier Transform Infrared) spectroscopy and DSC (Differential Scanning Calorimetry) thermal analysis. The painting materials employed by popular artists were determined by FTIR and XRF (X-ray fluorescence) spectroscopy as gypsum, calcite (rear background), lead white (Archangel Clothes), lead-minium (Archangel Clothes, leaf), iron oxide (Imperial Gate frame), malachite (green), Prussian blue (blue), orpiment (yellow), aliphatic, ester, and protein (probably egg yolk degradation products). Using similar colors as in the original artwork (resulting from the scientific investigation of the pigments) a 3D reconstruction has been performed. The restored Imperial Gates are placed in the old Nicula wooden church, being included into a tourist and religious circuit.

I. Bratu

Monk Siluan

C. M&#x103;ru&#x163;oiu

I. Kacso

S. Garabagiu

V. C. M&#x103;ru&#x163;oiu

C. T&#x103;n&#x103;selia

D. Popescu

D. L. Postolache

D. Pop

Science Applied for the Investigation of Imperial Gate from Eighteenth Century Wooden Church of Nicula Monastery

About this journal

<p><em>Journal of Spectroscopy</em> publishes research into the theory and application of spectroscopy across all disciplines, including biology, chemistry, engineering, earth sciences, medicine, materials science, physics, and space science.</p>


Journal profile

Meet the editorial board

<p>Chief Editor&nbsp;Dr Daniel Cozzolino&nbsp;is based at the University of Queensland, Australia. His research focuses on the developments of chemometric and spectroscopic methods for use in agriculture and food applications.</p>


Editor spotlight

Submit your proposal

Do you think there is an emerging area of research that really needs to be highlighted? Or an existing research area that has been overlooked or would benefit from deeper investigation? Raise the profile of a research area by leading a Special Issue.

Special Issues

Author guidelines

Editorial board

Databases and indexing

Journal of Spectroscopy - Table of contents 2017

title

Journal of Spectroscopy publishes research into the theory and application of spectroscopy across all disciplines, including biology, chemistry, engineering, earth sciences, medicine, materials science, physics, and space science.

Journal of Spectroscopy