scholarly journals Contactless Temperature Sensing at the Microscale Based on Titanium Dioxide Raman Thermometry

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 102
Author(s):  
Veronica Zani ◽  
Danilo Pedron ◽  
Roberto Pilot ◽  
Raffaella Signorini
Keyword(s):  
Titanium Dioxide ◽  
Scattered Light ◽  
Active Material ◽  
Local Temperature ◽  
Visible Range ◽  
Detection Techniques ◽  
Wide Range ◽  
Frequency Position ◽  
Anti Stokes

The determination of local temperature at the nanoscale is a key point to govern physical, chemical and biological processes, strongly influenced by temperature. Since a wide range of applications, from nanomedicine to nano- or micro-electronics, requires a precise determination of the local temperature, significant efforts have to be devoted to nanothermometry. The identification of efficient materials and the implementation of detection techniques are still a hot topic in nanothermometry. Many strategies have been already investigated and applied to real cases, but there is an urgent need to develop new protocols allowing for accurate and sensitive temperature determination. The focus of this work is the investigation of efficient optical thermometers, with potential applications in the biological field. Among the different optical techniques, Raman spectroscopy is currently emerging as a very interesting tool. Its main advantages rely on the possibility of carrying out non-destructive and non-contact measurements with high spatial resolution, reaching even the nanoscale. Temperature variations can be determined by following the changes in intensity, frequency position and width of one or more bands. Concerning the materials, Titanium dioxide has been chosen as Raman active material because of its intense cross-section and its biocompatibility, as already demonstrated in literature. Raman measurements have been performed on commercial anatase powder, with a crystallite dimension of hundreds of nm, using 488.0, 514.5, 568.2 and 647.1 nm excitation lines of the CW Ar+/Kr+ ion laser. The laser beam was focalized through a microscope on the sample, kept at defined temperature using a temperature controller, and the temperature was varied in the range of 283–323 K. The Stokes and anti-Stokes scattered light was analyzed through a triple monochromator and detected by a liquid nitrogen-cooled CCD camera. Raw data have been analyzed with Matlab, and Raman spectrum parameters—such as area, intensity, frequency position and width of the peak—have been calculated using a Lorentz fitting curve. Results obtained, calculating the anti-Stokes/Stokes area ratio, demonstrate that the Raman modes of anatase, in particular the Eg one at 143 cm−1, are excellent candidates for the local temperature detection in the visible range.

scholarly journals Biocompatible Temperature Nanosensors Based on Titanium Dioxide

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 16
Author(s):  
Veronica Zani ◽  
Danilo Pedron ◽  
Roberto Pilot ◽  
Raffaella Signorini
Keyword(s):  
Titanium Dioxide ◽  
Spatial Resolution ◽  
Optical Sensors ◽  
Scattered Light ◽  
Ccd Camera ◽  
Contactless Measurement ◽  
Temperature Detection ◽  
Frequency Position ◽  
Cooled Ccd ◽  
Anti Stokes

The measurement of temperature is of fundamental importance in a huge scale of applications, from nanomedicine, where the early detection of tumorous cells is an essential requirement, to microelectronics and microcircuits. Optical sensors with a micro/nano-spatial resolution can be used for temperature determination within a biological frame. Within this context, Raman spectroscopy is particularly interesting: the inelastic scattering of light has the advantage of a contactless measurement and exploits the temperature-dependence of intensities in the spectrum by observing the intensity ratio of anti-Stokes and Stokes signals. Titanium dioxide can be regarded as a potential optical material for temperature detection in biological samples, thanks to its high biocompatibility, already demonstrated in literature, and to its strong Raman scattering signal. The aim of the present work is the realization of biocompatible optical thermometers, with a sub-micrometric spatial resolution, made of titanium dioxide. Raman measurements have been performed on anatase powder using 514.5, 568.2 and 647.1 nm excitation lines of the CW Ar/Kr ion laser. The laser beam was focalized through a microscope on the sample, kept at defined temperature using a temperature controller. The Stokes and anti-Stokes scattered light was analyzed through a triple monochromator and detected by a liquid nitrogen-cooled CCD camera. Raw data were analyzed with Matlab and Raman spectrum parameters—such as area, intensity, frequency position and width of the peak—were calculated using a Lorentz fitting curve. Preliminary results showed that good reliable temperatures can be obtained.

scholarly journals QUANDO L’INSIEME È MEGLIO DELLA SOMMA: NANOMATERIALI IBRIDI ARGENTO-TITANIA ED ORO-TITANIA PER SENSORI ELETTROANALITICI

2020 ◽  
Author(s):  
Luigi Falciola ◽  
Valentina Pifferi ◽  
Anna Testolin
Keyword(s):  
Titanium Dioxide ◽  
Electrode Surface ◽  
Contact Region ◽  
Volume Ratio ◽  
Dominant Factor ◽  
Material Transport ◽  
Subsequent Increase ◽  
Intimate Contact ◽  
Wide Range

The interest of the scientific community for nanotechnologies and nanomaterials was born in 1959, on the occasion of the annual meeting of the American Physical Society, when a new approach began with which to consider and manipulate matter on a micro- and nano-metric scale. The subsequent increase in the use of nanomaterials in scientific research is due to their peculiar characteristics: increased surface / volume ratio, new optical and physical properties, high active surface, increased or modified material transport, increased selectivity. All these features make nanomaterials extremely suitable for a wide range of applications, from energy, to catalysis and sensors. In recent decades, apart from the application of nanomaterials characterized by a single component, the use of “hybrid” nanomaterials, composed of two or more components in “intimate” contact, is also rapidly growing. This is connected to the fact that, since in a hybrid material the establishment of synergistic properties is confined to the contact region between the different components, in nanomaterials, given the small size, these effects can become a dominant factor of the entire structure. The result is precisely the establishment of new and unexpected properties (often desired and interesting) which are not the simple sum of the ownership of individual contributions. Given all this, hybrid materials are excellent candidates for applications in the most varied fields, including electroanalysis, which can greatly benefit from these systems. In this context, this work aims to present the construction of devices based on hybrid metal-semiconductor nanomaterials (based on silver or gold nanoparticles and titanium dioxide). In these systems, the presence of metal nanoparticles is exploited for the electroanalytical determination of analytes of medical / diagnostic or environmental interest, while the presence of TiO2 is essential for overcoming the problems of fouling and passivation of the electrode surface following the determination of the molecule under examination. . The possibility of renewing the electrode surface simply by irradiating the device with ultraviolet light, allows you to use the devices remotely for a long time, without their continuous recovery. In the case of the Ag-TiO2 system, an “intimate contact” interphase between the silver nanoparticles and titanium dioxide was also found, which makes the hybrid a real new material, with different characteristics and with interesting applications compared to its precursors.

scholarly journals The Application of Nanosensors in Illicit Drugs Determination: A Review

2021 ◽  
pp. 39-59
Author(s):  
Lawal Shuaibu ◽  
AbduRahman Abdul Audu ◽  
Kingsley John Igenepo
Keyword(s):  
Optical Properties ◽  
Illicit Drugs ◽  
Illicit Drug ◽  
Drug Detection ◽  
Site Analysis ◽  
Detection Techniques ◽  
Wide Range ◽  
Qualitative Determination ◽  
Enhanced Selectivity

The utilization of nanomaterials (NMs) to produce nanosensors for detecting drugs in a wide range of materials has attracted global attention. Various categories of NMs have been synthesized and applied for the qualitative determination of some additives, contaminants, and illicit materials owing to their unique physicochemical properties at the nanoscale to impact desired effects. Rapid and facile detection techniques employed for on-site analysis of illicit drugs using NMs are reviewed. It is noted that NMs are good candidates in the fabrication of nanosensors for the sensitive detections and determinations of illicit drugs. Thus, this review is focused on the application of these sensors for illicit drug detection. Hence, the application of plasmonic/optical properties of NMs to enhance illicit drug detection in biological samples has been discussed. The fabricated sensors have been shown to possess enhanced selectivity, sensitivity, cost-effectiveness as well as improved automation. As highlighted in the in-depth review, the sensors are designed to utilize biological receptors with a transducer component to detect the analyte-biorecognition element interaction which resulted in producing an optimum signal. 

Correction Factor For Anthrone Carbohydrate in Coloured Wastewater Samples

1975 ◽  
Vol 10 (1) ◽  
pp. 126-131 ◽  
Author(s):  
A. Leduy ◽  
N. Kosaric ◽  
J.E. Zajic
Keyword(s):  
Correction Factor ◽  
Treatment Plant ◽  
Visible Range ◽  
Correction Factors ◽  
Total Carbohydrate ◽  
Water Solvent ◽  
Wide Range ◽  
Wastewater Samples ◽  
Anthrone Reagent

Abstract Spectrophotometric determination of total carbohydrate (TCH) in the wastewater samples by anthrone reagent is a simple and rapid method to follow the utilization of substrate, and hence the reduction of BOD5 load during the biological treatment process with chemoheterotrophs. However, for the coloured wastewater samples or treatment plant effluents, a correction factor was found necessary to compensate the colour inferences. Studies were conducted on various waste sulfite liquors (NH3-, Ca-, Mg-, Mixed- and Na-WSL) which provide a wide range of colours from creamy to black. The correction factor was calculated from the deviation of the standard calibration curves of glucose with and without the presence of WSL. These correction factors depended both on the nature and on the amount of WSL present. Within the practical dilution range of various WSL for the determination of TCH (1:1,000 - 4:1,000 v/v), the correction factors varied from 15 to 40%, which is highly significant if the correction was not made. In all WSL samples, the correction factor became more significant at higher concentration of WSL in the solution. Spectrophotometric studies of WSL at various concentrations within the visible range led to the development of the following empirical equation expressing their colour, $$\Lambda = \Lambda _{\rm s}\left( {1 + {[D_{\rm c}/D]}^2} \right)^{{\rm n/2}}$$ where Λ, Λs, Dc, D and n are the maximum transmitted wavelength of WSL solution, the maximum transmitted wavelength of water (solvent), the critical dilution of WSL, the dilution of WSL (reciprocal concentration of colouring materials) and the chromatic index of WSL respectively.

Polarimetric and photometric studies of lunar samples

1977 ◽  
Vol 285 (1327) ◽  
pp. 397-402 ◽  
Keyword(s):  
Phase Angle ◽  
Scattered Light ◽  
Degree Of Polarization ◽  
Surface Textures ◽  
Versus Phase ◽  
Maximum Value ◽  
Planetary Satellites ◽  
Wide Range ◽  
Lunar Samples

The polarization of scattered light has been investigated for lunar samples from six Apollo and two Luna missions. Over a wide range of the phase angle between incidence and observation directions, the light is found to be polarized only either normal (called positive) or parallel (negative) with respect to the incidence/observation plane. The resulting characteristic curves, of degree of polarization versus phase angle, are indicative of surface properties: the maximum value of polarization is inversely proportional to albedo, for dust-covered surfaces, and the slope is inversely proportional to albedo for most surfaces; the width and depth of the negative-going part of the curve indicate the type and complexity of the surface texture, as confirmed by Stereoscan photographs. This information may now be applied to the determination of albedos and surface textures for objects such as asteroids and planetary satellites, for which no samples are available but for which some polarization measurements have been made.

Determination of the profile of the temperature field of material heated by continuous laser radiation

2020 ◽  
pp. 51-10
Author(s):  
B.A. Lapshinov ◽  
◽  
N.I. Timchenko ◽  
Keyword(s):  
Temperature Field ◽  
Optical Fiber ◽  
Prolonged Exposure ◽  
Radiation Spectrum ◽  
Visible Range ◽  
Continuous Laser ◽  
Surface Temperature Distribution ◽  
Continuous Radiation ◽  
Spectral Pyrometry

Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.

DINAMIKA POLITIK PERSETUJUAN BERSAMA TENTANG PENETAPAN DESA ADAT DI KABUPATEN ROKAN HULU TAHUN 2014

2017 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Haryo Suganda ◽  
Raja Muhammad Amin
Keyword(s):  
Regulatory Region ◽  
Field Research ◽  
Analysis Techniques ◽  
Political Dynamics ◽  
Political Interests ◽  
Wide Range ◽  
Information Method ◽  
Qualitative Descriptive ◽  
The Village

This study is motivated the identification of policies issued by the regional Governmentof Rokan Hulu in the form of Regulatory region number 1 by 2015 on the determination of thevillage and Indigenous Village. Political dynamics based on various interests against themanufacture of, and decision-making in the process of formation of the corresponding localregulations determination of Indigenous Villages in the Rokan Hulu is impacted to a verysignificantamount of changes from the initial draft of the number i.e. 21 (twenty one) the villagebecame Customary 89 (eighty-nine) the Indigenous Villages who have passed. Type of thisresearch is a qualitative descriptive data analysis techniques. The research aims to describe theState of the real situation in a systematic and accurate fact analysis unit or related research, aswell as observations of the field based on the data (information). Method of data collectionwas done with interviews, documentation, and observations through fieldwork (field research).The results of the research on the process of discussion of the draft local regulations andmutual agreement about Designation of Indigenous Villages in the Rokan Hulu is, showed thatthe political dynamics that occur due to the presence of various political interests, rejectionorally by Villagers who were judged to have met the requirements of Draft Regulations to beformulated and the area for the set to be Indigenous Villages, and also there is a desire fromsome villages in the yet to Draft local regulations in order to set the Indigenous village , there isa wide range of interests of these aspects influenced the agreement to assign the entire localVillage which is in the Rokan Hulu become Indigenous village, and the village of Transmigrationinto administrative Villages where the initiator of the changes in the number of IndigenousVillages in the Rokan Hulu it is the desire of the local Government of its own.

scholarly journals Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

2021 ◽  
Vol 18 (4) ◽  
pp. 1768
Author(s):  
Hernâni Marques ◽  
Pedro Cruz-Vicente ◽  
Tiago Rosado ◽  
Mário Barroso ◽  
Luís A. Passarinha ◽  
...  
Keyword(s):  
Tobacco Smoke ◽  
Solid Phase ◽  
Smoke Exposure ◽  
Tobacco Smoke Exposure ◽  
World Health ◽  
Second Hand Smoke ◽  
Tobacco Exposure ◽  
Wide Range ◽  
Recent Developments

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

scholarly journals A coma-free super-high resolution optical spectrometer using 44 high dispersion sub-gratings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hua-Tian Tu ◽  
An-Qing Jiang ◽  
Jian-Ke Chen ◽  
Wei-Jie Lu ◽  
Kai-Yan Zang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Wavelength Region ◽  
Ultra Violet ◽  
High Spectral Resolution ◽  
Visible Range ◽  
High Dispersion ◽  
Charge Coupled Device ◽  
Wide Range ◽  
High Resolution Spectrometer

AbstractUnlike the single grating Czerny–Turner configuration spectrometers, a super-high spectral resolution optical spectrometer with zero coma aberration is first experimentally demonstrated by using a compound integrated diffraction grating module consisting of 44 high dispersion sub-gratings and a two-dimensional backside-illuminated charge-coupled device array photodetector. The demonstrated super-high resolution spectrometer gives 0.005 nm (5 pm) spectral resolution in ultra-violet range and 0.01 nm spectral resolution in the visible range, as well as a uniform efficiency of diffraction in a broad 200 nm to 1000 nm wavelength region. Our new zero-off-axis spectrometer configuration has the unique merit that enables it to be used for a wide range of spectral sensing and measurement applications.

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