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Gingival crevicular fluid (GCF) is a site-specific exudate deriving from the epithelium lining of the gingival sulcus. GCF analysis provides a simple and noninvasive diagnostic procedure to follow-up periodontal and bone remodeling in response to diseases or mechanical stimuli such as orthodontic tooth movement (OTM). In recent years, the use of vibrational spectroscopies such as Fourier Transform Infrared and Raman microspectroscopy and Surface-Enhanced Raman spectroscopy contributed to characterizing changes in GCF during fixed orthodontic treatment. Amide I band plays a relevant role in the analysis of these changes. The aim of this study was to investigate the spectroscopy response of Amide I depending on the OTM process duration. A model based on Gaussian–Lorentzian curves was used to analyze the infrared spectra, while only Lorentzian functions were used for Raman and SERS spectra. Changes induced by the OTM process in subcomponents of the Amide I band were determined and ascribed to secondary structure modification occurring in proteins. The vibrational spectroscopies allow us to efficiently monitor the effects of the orthodontic force application, thus gaining increasing attention as tools for individual patient personalization in clinical practice. [ABSTRACT FROM AUTHOR]

γ-rays can be efficiently detected by superconductor devices exploiting the interaction of single γ-ray photons with Abrikosov vortices [12]. In order to prove the feasibility of this novel detection mechanism, Josephson tunnel junctions were fabricated on bulk polycrystalline niobium base electrodes consisting of 0.3-mm-thick niobium foils, and investigated under 55Fe X-ray. The fabrication process is discussed with a particular attention to the treatment of the surface of the niobium foil. Niobium-bulk/Al/AlOx/Al/niobium Josephson junctions with different circular areas were tested at the temperature T = 4.2 K and their current–voltage and Josephson critical current dependence on parallel magnetic field were characterized. The experimental magnetic field dependences of the Josephson critical current have been well fitted by the Airy diffraction pattern. Depinning of Abrikosov vortices under X-ray photons has been observed by means of variation of the magnetic dependence of the Josephson critical current. [ABSTRACT FROM PUBLISHER]

Surface-Enhanced Raman Spectroscopy (SERS) enables the investigation of samples with weak specific Raman signals, such as opaque samples, including fruit juices and pulp. In this paper, biological apple juices and apple/pear pulp have been studied in order to evidence the presence of fructose and pectin, which are components of great relevance for quality assessment of these kinds of products. In order to perform SERS measurements a low-cost home-made substrate consisting of a glass slide decorated with 30-nm-sized gold nanoparticles has been designed and used. By employing a conventional micro-Raman spectroscopy set-up and a suitable data treatment based on "wavelet" denoising algorithms and background subtraction, spectra of pectin and fructose with clear Raman features have been obtained. The results have confirmed the potential of SERS in the food industry for product characterization, also considering the low-cost and the relative ease of the fabrication process of the employed SERS substrate. [ABSTRACT FROM AUTHOR]

Micro-Raman Spectroscopy is an efficient method for analyzing biological specimens due to its sensitivity to subtle chemical and structural changes. The aim of this study was to use micro-Raman spectroscopy to analyze chemical and structural changes in periodontal ligament after orthodontic force application and in gingival crevicular fluid in presence of periodontal disease. The biopsy of periodontal ligament samples of premolars extracted for orthodontic reasons and the gingival crevicular fluid samples collected by using absorbent paper cones; were analyzed by micro-Raman spectroscopy. Changes of the secondary protein structure related to different times of orthodontic force application were reported; whereas an increase of carotene was revealed in patients affected by periodontal inflammation. [ABSTRACT FROM AUTHOR]

Abstract: The voltage response of a Josephson junction to a pulsed terahertz current is evaluated in the limit of a negligible junction capacitance (overdamped limit). The time-dependent superconductor phase difference across the junction is calculated in the framework of the standard resistive shunted junction model by using a perturbative method. The pulsed current bias affects the time average value of the voltage across the junction and current steps are induced in the current–voltage characteristics for voltage values depending on the pulse repetition rate. The current step height is proportional to the square of the pulse time width (τ) to the period (T) ratio. A fast response detector for pulsed Terahertz radiation is proposed, with an expected responsivity of the order of 0.1V/W and an equivalent noise power of about 3×10−10 W/Hz1/2. [Copyright &y& Elsevier]

Micro-Raman spectroscopy is a very promising tool for medical applications, thanks to its sensitivity to subtle changes in the chemical and structural characteristics of biological specimens. To fully exploit these promises, building a method of data analysis properly suited for the case under study is crucial. Here, a linear or univariate approach using a R2 determination coefficient is proposed for discriminating Raman spectra even with small differences. The validity of the proposed approach has been tested using Raman spectra of high purity glucose solutions collected in the 600 to 1,600 cm-1 region and also from solutions with two known solutes at different concentrations. After this validation step, the proposed analysis has been applied to Raman spectra from oral human tissues affected by Pemphigus Vulgaris (PV), a rare life-threatening autoimmune disease, for monitoring disease follow-up. Raman spectra have been obtained in the wavenumber regions from 1,050 to 1,700 cm-1 and 2,700 to 3,200 cm-1 from tissues of patients at different stages of pathology (active PV, under therapy and PV in remission stage) as confirmed by histopathological and immunofluorescence analysis. Differences in the spectra depending on tissue illness stage have been detected at 1,150-1,250 cm-1 (amide III) and 1,420-1,450 cm-1 (CH3 deformation) regions and around 1,650 cm-1 (amide I) and 2,930 cm-1 (CH3 symmetric stretch). The analysis of tissue Raman spectra by the proposed univariate method has allowed us to effectively differentiate tissues at different stages of pathology. [ABSTRACT FROM AUTHOR]

The paper reports on results concerning the Si/YSZ/CeO2/YBCO multilayer prepared by means of magnetron sputtering. Such multilayer is considered for the possibility to compound the integration of YRCO Wins with silicon-based devices, with the unique, in perspective, properties of YBCO concerning photon sensors. We characterized YBCO films in such multilayer configuration by means of structural and dc transport measurements. It turns out that some granularity affects the transport properties of the YBCO film and lowers the critical currents. However, the lower temperature E — J characteristics are sharp enough to consider exploiting the transition between under critical and over critical (flux flow) state for future silicon-integrated broad-band photon sensors. [ABSTRACT FROM AUTHOR]

Monitoring the spore life cycle is one of the main issues in several fields including environmental control, sustainable ecosystems, food security, and healthcare systems. In this framework, the study of the living organism resistance to extreme conditions like those mimicking space environments is particularly interesting. The assessment of the local change of the pH level can be extremely useful for this purpose. An optical physiometer method based on the Raman response of the graphene, which is able to locally sense pH of a fluid on a micrometric scale, has been recently proposed. Due to the presence of π -bonds at the surface, the electronic doping of graphene is determined by the external conditions and can be electrochemically controlled or altered by the contact with an acid or alkaline fluid. The doping level affects the vibrational energies of the graphene that can be monitored by conventional Raman spectroscopy. In addition, Surface-Enhanced Raman Spectroscopy (SERS) can give direct information on the biochemical changes occurring in spore components. In this work, we propose the joint use of Graphene-Based Raman Spectroscopy (GbRS) and SERS for the monitoring of the response of spores to exposure to low temperatures down to 100 K. The spores of the thermophilic bacterium Parageobacillus thermantarcticus isolated from an active volcano of Antarctica (Mt. Melbourne) were investigated. These spores are particularly resistant to several stressing stimuli and able to adapt to extreme conditions like low temperatures, UV irradiation, and γ -rays exposure. The results obtained showed that the joint use of GbRS and SERS represents a valuable tool for monitoring the physio-chemical response of bacterial spores upon exposure to stressing stimuli. [ABSTRACT FROM AUTHOR]

Tears are exceptionally rich sources of information on the health status of the eyes, as well as of whole body functionality, due to the presence of a large variety of salts and organic components whose concentration can be altered by pathologies, eye diseases and/or inflammatory processes. Surface enhanced Raman spectroscopy (SERS) provides a unique method for analyzing low concentrations of organic fluids such as tears. In this work, a home-made colloid of gold nanoparticles has been used for preparing glass substrates able to efficiently induce an SERS effect in fluid samples excited by a He–Ne laser (λ = 633 nm). The method has been preliminary tested on Rhodamine 6G aqueous solutions at different concentrations, proving the possibility to sense substance concentrations as low as few μ M, i.e., of the order of the main tear organic components. A clear SERS response has been obtained for human tear samples, allowing an interesting insight into tear composition. In particular, aspartic acid and glutamic acid have been shown to be possible markers for two important human tear components, i.e., lactoferrin and lysozyme. [ABSTRACT FROM AUTHOR]

Graphene provides a unique way of sensing the local pH level of substances on the micrometric scale, with important implications for the monitoring of cellular metabolic activities where proton excretion could occur. Accordingly, an innovative biosensing approach for the quantification of the pH value of biological fluids, to be used also with small amounts of fluids, was realized and tested. It is based on the use of micro-Raman spectroscopy to detect the modifications of the graphene doping level induced by the contact of the graphene with the selected fluids. The approach was preliminarily tested on aqueous solutions of known pH values. It was then used to quantify the pH values of cell culture media directly exposed to different doses of X-ray radiation and to media exposed to X-ray-irradiated cells. The Raman response of cells placed on graphene layers was also examined. [ABSTRACT FROM AUTHOR]

Abstract: The coherence length ξ c along c-axis direction in (103)/(013) oriented YBCO superconductor thin films has been evaluated from the temperature dependence of current–voltage (I–V) characteristics of micro-bridges in the framework of a model taking in account thermally activated magnetic flux creep in the intrinsic potential of the layered structure of the superconductor. The coherence length gradually increased from the initial value ξ c =0.14nm to ξ c =0.33nm in the sample subjected to subsequent annealing steps performed in air at increasing temperatures from a range T a =190–275°C. Structural modifications of deoxygenated samples were monitored by micro-Raman spectroscopy. The critical temperature T c slightly increases after the initial annealing steps while a significant T c decrease has been observed after T a =275°C stage accompanied by appearance of the tetragonal phase in the crystal structure. [Copyright &y& Elsevier]

• Electron writing in thin YBCO films using standard TEM equipment is possible. • Electron beam processing of epitaxial YBCO films depends on the film substrate used. • High fluency irradiation effects are stronger in YBCO on MgO than in YBCO on LSAT. • Mismatch of the YBCO structure to the substrate leads to heat confinement effects. The influence of substrate material on electron writing (EW) procedures directed at fabrication of artificial channels for easy vortex motion in YBa 2 Cu 3 O 7−δ (YBCO) epitaxial thin films has been investigated. Films deposited on two types of substrates providing epitaxial growth, magnesium oxide (MgO) and La 0.18 Sr 0.82 Al 0.59 Ta 0.41 O 3 (LSAT) substrates, have been irradiated in a standard electron transmission microscope with low and high fluency 30 keV electrons. The effects of irradiation have been assessed by the measurements of the superconducting transition temperature and the critical current, completed by the micro-Raman spectroscopy and transmission electron microscopy structural investigations. The irradiation effects were found to depend on the type of substrate on which films were deposited. Differences have been attributed to distinct structural properties of the films, resulting from different matching of substrates lattices to the YBCO crystalline lattice. A stronger mismatch of MgO substrates causes the formation of in-plane disoriented epitaxial grains and significant heat confinement during EW procedures. Heat confinement mechanism, together with differences in the thermal properties of the substrates enables understanding the performance of different YBCO films in electron writing procedures. [ABSTRACT FROM AUTHOR]

The aim of the study was to examine the biochemical and structural changes occurring in the periodontal ligament (PDL) during orthodontic-force application using micro-Raman spectroscopy ( μ-RS). Adolescent and young patients who needed orthodontic treatment with first premolar extractions were recruited. Before extractions, orthodontic forces were applied using a closed-coil spring that was positioned between the molar and premolar. Patients were randomly divided into three groups, whose extractions were performed after 2, 7, and 14 days of force application. From the extracted premolars, PDL samples were obtained, and a fixation procedure with paraformaldehyde was adopted. Raman spectra were acquired for each PDL sample in the range of 1000–3200 cm−1 and the more relevant vibrational modes of proteins (Amide I and Amide III bands) and CH2 and CH3 modes were shown. Analysis indicated that the protein structure in the PDL samples after different time points of orthodontic-force application was modified. In addition, changes were observed in the CH2 and CH3 high wavenumber region due to local hypoxia and mechanical force transduction. The reported results indicated that μ-RS provides a valuable tool for investigating molecular interchain interactions and conformational modifications in periodontal fibers after orthodontic tooth movement, providing quantitative insight of time occurring for PDL molecular readjustment. [ABSTRACT FROM AUTHOR]

Gingival crevicular fluid (GCF) is a site-specific exudate in the gingival sulcus. GCF composition changes in response to diseases or mechanical stimuli, such as those occurring during orthodontic treatments. Raman microspectroscopy ( μ -RS) and surface-enhanced Raman spectroscopy (SERS) were adopted for a GCF analysis during different initial phases of orthodontic force application. GCF samples were pooled from informed patients using paper cones. SERS spectra were obtained from GCF extracted from these cones, whereas μ -RS spectra were directly acquired on paper cones without any manipulation. The spectral characteristics of the main functional groups and the changes in cytochrome, amide III, and amide I contributions were highlighted in the different phases of orthodontic treatment with both SERS and μ -RS analysis. μ -RS directly performed on the paper cones together with proper statistical methods can offer an effective approach for the development of a tool for monitoring the processes occurring during orthodontic treatments, which may help the clinician in the choice of type of treatment individually for each patient and accelerate and improve the orthodontic therapy. [ABSTRACT FROM AUTHOR]

A micro-Raman spectroscopy investigation has been performed in vitro on single human mammary epithelial cells after irradiation by graded x-ray doses. The analysis by principal component analysis (PCA) and interval-PCA (i-PCA) methods has allowed us to point out the small differences in the Raman spectra induced by irradiation. This experimental approach has enabled us to delineate radiation-induced changes in protein, nucleic acid, lipid, and carbohydrate content. In particular, the dose dependence of PCA and i-PCA components has been analyzed. Our results have confirmed that micro-Raman spectroscopy coupled to properly chosen data analysis methods is a very sensitive technique to detect early molecular changes at the single-cell level following exposure to ionizing radiation. This would help in developing innovative approaches to monitor radiation cancer radiotherapy outcome so as to reduce the overall radiation dose and minimize damage to the surrounding healthy cells, both aspects being of great importance in the field of radiation therapy. [ABSTRACT FROM AUTHOR]

Optical vibrational techniques show a high potentiality in many biomedical fields for their characteristics of high sensitivity in revealing detailed information on composition, structure, and molecular interaction with reduced analysis time. In the last years, we have used these techniques for investigating gingival crevicular fluid (GCF) and periodontal ligament (PDL) during orthodontic tooth treatment. The analysis with Raman and infrared signals of GCF and PDL samples highlighted that different days of orthodontic force application causes modifications in the molecular secondary structure at specific wavenumbers related to the Amide I, Amide III, CH deformation, and CH3/CH2. In the present review, we report the most relevant results and a brief description of the experimental techniques and data analysis procedure in order to evidence that the vibrational spectroscopies could be a potential useful tool for an immediate monitoring of the individual patient's response to the orthodontic tooth movement, aiming to more personalized treatment reducing any side effects. [ABSTRACT FROM AUTHOR]

Significance: A noninvasive method based on surface-enhanced Raman spectroscopy (SERS) of tears was proposed as a support for diagnosing neurodegenerative pathologies, including different forms of dementia and Alzheimer's disease (AD). In this field, timely and reliable discrimination and diagnosis are critical aspects for choosing a valid medical therapy, and new methods are highly required. Aim: The aim is to evince spectral differences in SERS response of human tears from AD affected, mild cognitive impaired (MCI), and healthy control (Ctr) subjects. Approach: Human tears were characterized by SERS coupled with multivariate data analysis. Thirty-one informed subjects (Ctr, MCI, and AD) were considered. Results: Average SERS spectra from Ctr, MCI, and AD subjects evidenced differences related to lactoferrin and lysozyme protein components. Quantitative changes were also observed by determining the intensity ratio between selected bands. We also constructed a classification model that discriminated among AD, MCI, and Ctr subjects. The model was built using the scores obtained by performing principal component analysis on specific spectral regions (i-PCA). Conclusions: The results are very encouraging with interesting perspectives for medical applications as support of clinical diagnosis and discrimination of AD from other forms of dementia. [ABSTRACT FROM AUTHOR]