NIR Radiation Research Articles

FT-NIR analysis of different garlic cultivars

Garlic represents a source of various biologically active phytomolecules. The content of phenolic compounds in garlic varies greatly with genetic, agronomic, and environmental factors, and the cultivar is the primary factor which determines this variation. The aim of this study was to analyse by Fourier transform near infrared spectroscopy (FT-NIR) different garlic cultivars, organically grown or commercial ones, coming from four different geographical areas. Garlic samples were collected from four different locations, and then analyse in the spectral range of the NIR radiation, which extends from 800 to 2500 nm, using three different modules (integrating sphere, transmission and fibre optic modules) that provide tools for analysing most liquid and solid samples. For all the measurements, no sample preparation was performed, since this analytical technique is non-invasive and non-destructive, and each sample was subject to repeated measurements. All the FT-NIR garlic spectra were undergone to a post processing analysis and compared between them. The comparison enhanced a clear distinction between biological and commercial garlic spectra. In particular, the last ones were characterised by a greater number of absorption peaks. This different trend in the FT-NIR spectra could be related to the possible contamination by toxic waste of the cultivation soil. Consumers are gradually looking for quality seals and trust marks on food products, and expected manufacturers and retailers to provide products of high quality. In this context, the FT-NIR represents a valid instrument for food classification and an important task for quality control and identification of foodstuff product adulteration.

Photothermal Superheating of Water with Ion‐Implanted Silicon Nanowires

Nanoparticle-mediated photothermal (PT) cancer therapy has been a major focus in nanomedicine due to its potential as an effective, non-invasive, and targeted alternative to traditional cancer therapy based on small-molecule pharmaceuticals[1,2]. Gold nanocrystals have been a primary focus of PT research[3], which can be attributed to their size tunability[4], well understood conjugation chemistry[5], and efficient absorption of NIR radiation in the tissue transparency window (800 nm – 1 μm) due to their size-dependent localized surface plasmon resonances[6].

Printed Smart Photovoltaic Window Integrated with an Energy‐Saving Thermochromic Layer

A smart photovoltaic window is designed and constructed by solution-processing a layer of thermochromic VO2 nanoparticles on top of a semitransparent organic solar cell. The prepared smart window not only produces electricity using the visible part of the solar spectrum but also saves energy via intelligently modulating the amount of NIR radiation passing through the device in response to ambient temperature.

Doxorubicin‐Loaded Single Wall Nanotube Thermo‐Sensitive Hydrogel for Gastric Cancer Chemo‐Photothermal Therapy

Single wall carbon nanotube (SWNT) based thermo‐sensitive hydrogel (SWNT‐GEL) is reported, which provides an injectable drug delivery system as well as a medium for photothermal transduction. SWNT‐hydrogel alone appears to be nontoxic on gastric cancer cells (BGC‐823 cell line) but leads to cell death with NIR radiation through a hyperthermia proapoptosis mechanism. By incorporating hyperthermia therapy and controlled in situ doxorubicin (DOX) release, DOX‐loaded SWNT‐hydrogel with NIR radiation proves higher tumor suppression rate on mice xenograft gastric tumor models compared to free DOX without detectable organ toxicity. The developed system demonstrates improved efficacy of chemotherapeutic drugs which overcomes systemic adverse reactions and presents immense potential for gastric cancer treatment.

Forensic and security applications of a long‐wavelength dispersive Raman system

A novel dispersive system operating at 1064‐nm excitation and coupled with transfer electron InGaAs photocathode and electron bombardment CCD technology has been evaluated for the analysis of drugs of abuse and explosives. By employing near‐IR excitation at 1064‐nm excitation wavelength has resulted in a significant damping of the fluorescence emission compared to 785‐nm wavelength excitation. Spectra of street samples of drugs of abuse and plastic explosives, which usually fluoresce with 785‐nm excitation, are readily obtained in situ within seconds through plastic packaging and glass containers using highly innovative detector architecture based upon a transfer electron (TE) photocathode and electron bombarded gain (EB) technology that allowed the detection of NIR radiation at 1064 nm without fluorescence interference. This dispersive near‐IR Raman system has the potential to be an integral part in the armoury of the forensic analyst as a non‐destructive tool for the in‐situ analysis of drugs of abuse and explosives. Copyright © 2015 John Wiley & Sons, Ltd.

Optical nonlinearity and electric conductivity origin study on sucrose crystal by using IR, Raman, INS, NMR, and EPR spectroscopies

The supposed importance of hydrogen bonds toward the origin of second harmonic generation (SHG) and electric conductivity in crystalline sucrose was investigated by IR (4000–10cm−1), INS (2000–10cm−1, at 35K), polarized Raman (3600–50cm−1) spectra, and 1H NMR second moment line records in the temperature range 450–80K. The temperature dependence of NIR (7000–5500cm−1) polarized spectra gave information about –CH2 motions complementary to NMR results concerning –CH2OH group rearrangements. The EPR spectra were applied to study the generation of radical ions by exposure to NIR radiation. Density functional theory quantum chemical calculations were performed to reproduce the vibrational spectra in order to complete as far as possible the assignments of bands observed by us and in the literature in sucrose crystals, and to throw more light on the possible reasons of sucrose electric conductivity and optical nonlinearity by the knowledge of theoretical values of dipole moments, polarizabilities, first order hyperpolarizabilities of sucrose molecule and clusters as well as ionization energy and electron affinity. The proton transfer in one specific hydrogen bond parallel to the helical axis b is proposed to be the most important in SHG and conductivity origin.

Optical Properties of Gold Nanorattles: Evidences for Free Movement of the Inside Solid Nanosphere

Gold nanorattles (AuNRTs), hollow gold nanospheres with internal small solid gold nanospheres (AuNSs), were prepared with different sizes. The presence of AuNS inside the hollow gold nanospheres in the nanorattle shape was found to improve their sensing efficiency. The sensitivity factor of the nanorattles is in the range of 450 nm/RIU, while the individual hollow nanosphere’s efficiency is ∼300 nm/RIU. This improvement is due to the strong plasmon field on the cavity and around the inner gold nanosphere as shown by using the discrete dipole approximation (DDA) calculations. Interestingly, this nanoparticle produces a strong enhancement for the interaction of light at 850 nm due to the excitation of both the inner sphere and outer nanoshell, despite being the fact that NIR radiation (850 nm) has very low energy to excite the inner gold nanosphere when present alone. Comparing the experimental and simulated scattering spectrum for a single colloidal nanorattle suggests that the interior gold nanosphere mov...

DEVELOPMENT OF ELECTRICITY PRODUCING GREENHOUSES - TWO CASE STUDIES

ISHS International Symposium on New Technologies for Environment Control, Energy-Saving and Crop Production in Greenhouse and Plant Factory - Greensys 2013 DEVELOPMENT OF ELECTRICITY PRODUCING GREENHOUSES - TWO CASE STUDIES

Evaluation of the Salt Content of Canned Sardines in Tomato Ketchup by Diffuse Reflection near Infrared Spectroscopy

This research aimed to determine the salt content of canned sardines in tomato sauce using NIR spectroscopy compared with traditional methods employing an auto-titrator, which are more consuming in terms of time and chemicals used. Scanning of NIR radiation was performed using an FT-NIR spectrometer with a wavenumber range of 12,500–4000 cm−1 (800–2500 nm) with the diffuse reflection mode. Model development was achieved using partial least-squares regression from three groups of samples, which were the sample group that included salt-adjusted samples, the sample group that did not include salt-adjusted samples and the sample group that included only salt-adjusted samples plus five non-salt-adjusted samples. The model from the sample group that did not include salt-adjusted samples used the first derivative + straight-line subtraction spectra between 9403.8 cm−1 and 4242.9 cm−1 with nine partial least-squares factors providing the lowest root mean square error of prediction ( RMSEP), with a coefficient of determination of calibration ( R2) of 0.90, root mean square error of estimation of 0.039%, coefficient of determination for prediction ( r2) of 0.85, RMSEP of 0.046%, average error of prediction (bias) of −0.002% and ratio of standard error of validation to the standard deviation of 2.58. The sample group that included salt-adjusted samples had a skewed distribution. The model returned an RMSEP of 0.109% on test samples, but the performance-to-interquartile range index indicated that this was a poor calibration. For the smaller salt-adjusted samples plus five non-salt-adjusted samples, cross-validation indicated the potential to evaluate salt in canned sardines (root mean square error of cross-validation = 0.158%). It was found that the vibration of water had an effect on the prediction accuracy as well as the vibration of starch and protein. In addition, the CONH2 and CO2H groups, which are common amino acid functional groups, also showed an effect. These findings represent novel findings concerning the use of NIR spectroscopy to determine salt that has no signal of its own in the NIR region.

Anti-biofouling conducting polymer nanoparticles as a label-free optical contrast agent for high resolution subsurface biomedical imaging

Optical coherence tomography (OCT) is a modern high resolution subsurface medical imaging technique. Herein we describe: (i) the synthesis of a thiophene-functionalized oligo(ethylene glycol) methacrylate (OEGMA)-based statistical copolymer, denoted poly(2TMOI–OEGMA); (ii) the preparation of sterically-stabilized polypyrrole (PPy) nanoparticles of approximately 60 nm diameter; (iii) the evaluation of these nanoparticles as a NIR-absorbing optical contrast agent for high-resolution OCT imaging. We show that poly(2TMOI–OEGMA)-stabilized PPy nanoparticles exhibit similar optical properties to poly(vinyl alcohol) (PVA)-stabilized PPy nanoparticles of comparable size prepared using commercially available PVA. Spectroscopic measurements and Mie calculations indicate that both types of PPy nanoparticles strongly absorb NIR radiation above 1000 nm, suggesting their potential use as OCT contrast agents. In vitro OCT studies indicate that both types of PPy nanoparticles reduce NIR backscattering within homogeneous intralipid tissue phantoms, offering almost identical contrast performance in this medium. However, PVA-stabilized PPy nanoparticles became colloidally unstable when dispersed in physiological buffer and immersed in a solid biotissue phantom and hence failed to generate a strong contrast effect. In contrast, the poly(2TMOI–OEGMA)-stabilized PPy nanoparticles remained well-dispersed and hence exhibited a strong rapid onset contrast effect within the biotissue phantom under identical physiological conditions. Ex vivo studies performed on excised chicken and porcine skin tissue demonstrated that topical administration of a low concentration of poly(2TMOI–OEGMA)-stabilized PPy nanoparticles rapidly enhances OCT image contrast in both cases, allowing key tissue features to be readily identified.

Photoactivity of S-doped nanoporous activated carbons: A new perspective for harvesting solar energy on carbon-based semiconductors

Photoactivity of S-doped nanoporous carbons was tested using photocurrent generation, cyclic voltammetry and photodegradation of methylene blue (MB) under artificial solar irradiation. The results were compared to those obtained on unmodified carbons and on commercial TiO2. A significant generation of photocurrent at visible and NIR radiation from 400 to 1200nm was found. An exposure to ambient light has a strong effect on an open circuit potential indicating the strong activity of S-doped carbons in oxidation reactions. The activity in the process of MB degradation was about 2.2 and 1.9 higher than that obtained on a commercial TiO2. The extent of photoactivity depends both on the composition of the activated carbon and on the sulfur content. The results suggest that incorporation of sulfur decreases the energy band gap in activated carbon.

Structural, thermal, and optical properties of Pr3+/Yb3+ co-doped oxyhalide tellurite glasses and its nano-crystalline parts

Nano-crystalized glass-ceramics and ceramics co-doped with Pr3+/Yb3+ have been successfully prepared by heat treatment of the precursor oxyhalide glass sample synthesized by melt-quench method. Thermal measurement of glass sample shows its glass transition temperature (Tg), and onset crystallization temperature (Tc). Formation of nano-crystals was verified by X-ray diffraction patterns and transmission electron microscopy (TEM) images. Values of optical band gap (Eopt) were found to be 2.85 eV and 1.54 eV for direct and indirect transitions, respectively. Up and downconversion emission spectra recorded with 976 and 532 nm laser wavelengths show emission from Pr3+ ions. Emission of Pr3+ enhances approximately thirty times when Yb3+ ion is added with the matrix. The Stark splitting and the intensity of different emission bands increase effectively when we approach to ceramic via glass-ceramic sample. Intense upconversion emission observed by naked eyes has been quantified in terms of standard chromaticity diagram (CIE). Power dependence study shows that the upconversion of NIR radiation to visible takes place mainly via photon avalanche (PA) process. Upconversion mechanisms have been discussed in terms of excited state absorption (ESA) and energy transfer (ET) processes.

Quantum‐Dot‐Tagged Reduced Graphene Oxide Nanocomposites for Bright Fluorescence Bioimaging and Photothermal Therapy Monitored In Situ

Quantum-dot-tagged reduced graphene oxide (QD-rGO) nanocomposites (left) internalized into targeted tumor cells display bright fluorescence from the QDs (right); by absorbing NIR radiation incident on the rGO and converting it into heat, they also cause simultaneous cell death and fluorescence reduction (bottom). The nanocomposite is thus capable of tumor imaging, photothermal therapy and in situ monitoring of treatment in progress.

Spectral Measurement and Analysis of Silicon CMOS Light Sources

The emission spectra of pn-junction and punch-through (PT) carrier injection silicon (Si) CMOS light sources were measured at various current densities and temperatures. In contrast to the narrow-band forward-biased junction spectrum, that peaks around 1.1 μm (1.1 eV), the reverse-bias spectrum was found to extend from about 350 nm (3.4 eV) to about 1.7 μm (0.7 eV) covering the UV, Vis and NIR regions. Since the photon energy decreases with increasing wavelength, the significant NIR radiation implies that the quantum conversion efficiency of Si avalanche light sources is appreciably higher than previously reported. Calculating the photon flux at the emission source within the Si against photon energy allowed the deduction and quantification of the physical light emission processes with respect to silicon's electronic band structure. Intra-conduction-band (c-c) electron (e - ) transitions seem to be the dominant physical mechanism responsible for the wide avalanche spectrum.

Use of near-infrared radiation for oxygenic photosynthesis via photon up-conversion

Radiation between 400 and 700 nm, used for oxygenic photosynthesis by cyanobacteria, algae and plants, represents only 44% of total solar energy while the range above 700 nm comprises 52%. An ability to use near infrared (NIR, 700–1200 nm) radiation would greatly improve the efficiency of photosynthesis, but NIR photons have too low energy to excite the photosystems of oxygenic photosynthesis. Here we show that a mechanism called photon up-conversion can turn NIR radiation into an energy source for photosynthesis. In the future, it may be possible to up-convert the NIR part of the solar energy flux to visible light for use in photo-induced biohydrogen production by oxygenic photosynthesis.

Spontaneous tunneling and near-infrared-induced interconversion between the amino-hydroxy conformers of cytosine

Spontaneous and near-infrared/infrared (NIR/IR)-induced interconversions between two amino-hydroxy conformers of monomeric cytosine have been investigated for the compound isolated in a low-temperature argon matrix. Combined use of a laser source (which provides narrowband NIR radiation) and a broadband NIR/IR source of excitation light allowed a detailed investigation of mutual conversions of the two conformers in question. The experiments carried out within the current work demonstrated that upon broadband NIR/IR irradiation (with the IR source of FTIR spectrometer) the population ratio of the two amino-hydroxy conformers changes towards a ratio corresponding to a photostationary state. Evolution of the conformer population ratio towards the photostationary ratio occurred independent of the initial ratio of conformers, which could be prepared by a population shift (in favor of one of the forms) induced by narrowband NIR excitation. Moreover, spontaneous tunneling conversion of the higher-energy conformer into a lower-energy form was observed for cytosine isolated in a low-temperature argon matrix kept in the dark. This process is slow and occurs on a time scale of days. The tunneling process, studied for matrix-isolated cytosine, clearly follows a dispersive type of kinetics rather than the classical monoexponential kinetics.

CALCULATION OF NIR EFFECT ON GREENHOUSE CLIMATE IN VARIOUS CONDITIONS

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Greenhouse 2010 and Soilless Cultivation CALCULATION OF NIR EFFECT ON GREENHOUSE CLIMATE IN VARIOUS CONDITIONS

Structural, thermal, and optical properties of Er3+/Yb3+ co-doped oxyhalide tellurite glasses, glass-ceramics and ceramics

Glass-ceramics and ceramics containing nano-crystals of different phases doped with Er3+/Yb3+ ions have been successfully prepared by heat treatment of the precursor oxyhalide glasses synthesized by the melt-quench method. X-ray diffraction patterns and transmission electron microscopy (TEM) images verify the precipitation of nano-crystals. Emission of Er3+ enhances several times when Yb3+ ion is added with the matrix. The Stark splitting and the intensity of different emission bands increase to a great extent when we approach to ceramics from glasses via glass-ceramics. The intensity of the blue and green emission bands increases much faster than the red and NIR emission bands. Intense upconversion emission observed by the naked eye has been quantified in terms of standard chromaticity diagram (CIE). Power dependence study shows that the upconversion of NIR radiation to visible radiation takes place mainly via photon avalanche (PA) process.

Modeling energy and carbon fluxes in a heterogeneous oak woodland: A three-dimensional approach

Most land surface and ecosystem models assume that a vegetated canopy can be abstracted as a turbid medium when such models compute mass, energy, and carbon exchange. However, those models fail to simulate radiation environments in heterogeneous landscapes. This study aims to couple a spatially explicit three-dimensional (3D) shortwave and longwave radiative transfer model with a soil and canopy energy balance and canopy physiology model (CANOAK-FLiES), to investigate how well the 3D model performs in a heterogeneous landscape compared to a 1D model. The canopy structural parameters were extracted using airborne-based Light Detection and Ranging (LiDAR) data and digital cover photographs. The developed model was compared with a wide variety of field and remote sensing data (e.g., hyper-spectral remote sensing images, overstory and understory radiation, and tower-based energy and CO 2 fluxes) in a woody oak savanna in CA, USA. Overall, the simulated spatial and diurnal patterns of the radiation environment were consistent with the measurements of shortwave and longwave wavebands. The 3D approach worked better than the 1D approach from the wet mild spring to the dry hot summer while the relative importance of using the 3D approach depends on climate and canopy physiological conditions as well as the canopy structure. With low leaf area index in the oak woodland, the woody elements absorbed 12%–39% of the PAR and 20%–52% of the NIR radiation. Consequently, 12% of the daytime energy flux was used as woody heat storage at our study site. This novel 3D model has the potential to serve as a useful tool for analyzing the spatio-temporal variability of radiation and energy fluxes in evaluating footprints of radiation sensors and eddy covariance fluxes, and serve as a standard in evaluating the performance of a hierarchy of simpler land surface models to compute mass and energy exchange of heterogeneous landscapes.

Impact of two DNA repair pathways, homologous recombination and non-homologous end joining, on bacterial spore inactivation under simulated martian environmental conditions

Spores of Bacillus subtilis were used as a model system to study the impact of the two major DNA double-strand break (DSB) repair mechanisms [homologous recombination (HR) and non-homologous end-joining (NHEJ)] on the survivability of air-dried mono- and multilayers of bacterial spores under a simulated martian environment; i.e., an environment with low temperature (−10 °C), pure CO 2 atmosphere (99.99% CO 2), 200–1100 nm UV–VIS–NIR radiation, and 0.69 kPa pressure. Spores in multilayers exhibited low inactivation rates compared to monolayers, mainly due to shadowing effects of overlying spores. Simulated martian UV irradiation reduced dramatically spore viability, whereas when shielded from martian UV radiation, spores deficient in NHEJ- and HR-mediated DNA repair were significantly more sensitive to simulated martian environmental conditions than were wild-type spores. In addition, NHEJ-deficient spores were consistently more sensitive than HR-deficient spores to simulated Mars environmental conditions, suggesting that DSBs were an important type of DNA damage. The results indicated that both HR and NHEJ provide an efficient set of DNA repair pathways ensuring spore survival after exposure to simulated martian environmental conditions.