Current Articles in the field of NIR Spectroscopy published online in scientific journals.
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On this page considered biochemistry journals:
Journal of Near Infrared Spectroscopy - published by
NIR Publications -
JNIRS is a bimonthly, peer review journal dedicated to all aspects of NIR spectroscopy and technology with the publication of original research papers, short communications, review articles and letters.
Current research articles of the mentioned
journals:
The aim of this study was to determine the feasibility of using near infrared (NIR) spectroscopy
to identify motor and sensory fascicles. Using 12 adult Beagle dogs which were anesthetised generally and sacrificed, canalis vertebralis were opened and both anterior
and posterior roots were harvested from the first lumbar vertebrae to the second sacral vertebrae (L1–S2). A total of 126 anterior roots and 126
posterior roots were collected. NIR diffuse reflectance spectra were measured using a Fourier transform near infrared (FT-NIR) spectrometer fitted with a fibre-optic probe. The
average spectrum of each sample was used for further analysis. There were no clear differences from the spectra between the anterior and posterior root samples. Original
spectral data were transformed to second derivative spectral data. Soft independent modelling of class analogy (SIMCA) was employed to identify the anterior and posterior roots
based upon differences in their spectral features. SIMCA models correctly classified 79–100% for the anterior and posterior roots and mean 83.7%. This study
demonstrated that NIR spectroscopy in combination with pattern recognition methods (SIMCA) could be used to classify the anterior and posterior roots. This result suggests that
NIR spectroscopy may provide a rapid, correct, non-destructive, low-cost means to quickly differentiate motor and sensory fascicles in mixed nerves.
In the cotton industry the most important parameters for quality of seed cotton (unginned, harvested cotton) are moisture
content and impurity level. In Spain, these quality parameters are regulated and cotton producers are awarded incentives. This study was performed to investigate the potential of
near infrared (NIR) spectroscopy for determining moisture content and impurity level of seed cotton. A total of 100 cotton samples collected from eight cotton ginners were used.
Two spectrometers were employed, one a research level instrument (Foss NIRSystems 6500), the other with a reduced wavelength range more suitable for use at-line (InfraXact
Lab). Moisture content was measured using a moisture meter, which is used in cotton industry, and by a drying oven technique. Impurity level was determined by gravimetric
analysis. Partial least square regression and classification were performed for moisture and impurity level of cotton, respectively. In sample preparation, the NIRSystems 6500 with
a back cover of the sample cell was better in repeatability of spectra than the InfraXact Lab with no back cover. For moisture, the best calibration was developed by using the
reference values from the oven drying method and using the first derivative and standard normal variate and detrending as pre-processing of the spectral data, giving a standard
error of 0.44% in the range of 5.83–14.96% moisture content. The classification model for the impurity level was developed with a combination of first derivative and
multiplicative scatter correction of the spectral data and resulted in an accuracy of 80%. For both moisture and impurity parameters, using the NIRSystems 6500 instrument gave
slightly better results than using the InfraXact Lab.
A sequential batch reactor (SBR) for aerobic treatment of dairy residues (activated sludge process) was monitored on-line by near infrared (NIR)
spectroscopy. NIR spectra in the wavelength range of 900–1700 nm were acquired in situ with a transflectance probe. Measured in situ NIR spectra allowed
the development of multivariate statistical process control models for supervision of the SBR process. The directly acquired spectra permitted characterisation of the different SBR
operation stages and the detection of process disturbances. Calibration models based on partial least squares regression were developed for three process parameters: total
solids (TS), total suspended solids (TSS) and chemical oxygen demand (COD). Model errors were estimated as root mean squared errors of cross-validation (RMSECV).
The cross-validation errors obtained were 0.066 g TS L–1, 0.075 g TSS L–1 and 86.6 mg O2L–1
respectively. Results demonstrated the viability of NIR spectroscopy as an alternative method for monitoring and control of activated sludge wastewater treatment processes
having advantages both in terms of efficient determination of process parameters (fast, in situ and requiring no toxic reagents) and in terms of process monitoring.
The selection of five naturally occurring selenite minerals that contain two different transition metal ions, Cu2+ and Co2+could
be distinguished by near infrared spectroscopy. Dependence of composition on spectral properties is a key to mineral identification and differentiation of the members of the
selenite group. The nature of the band positions and splitting of band components in the electronic spectra of Cu2+ selenites in the region 12400–8000
cm–1 are in conformity with octahedral geometry distortion. The two split components which are observed for the Co2+ band near 9000
cm–1 in cobaltomenites are considered as the vibrational satellites of spin-allowed transition 4T1g(F) → 4T2g(F). Bands observed at 6950
cm–1, 6810 cm–1 and 6700 cm–1 are the overtones of OH stretches of structural water in selenites and a strong
absorption feature near 6700 cm–1 is the result of hydrogen bonding between (SeO3)2– and H2O. These
bands are shifted in cobaltomenites. A sharp absorption band at 5170 cm–1 is a common feature in all the spectra of selenite minerals and is the contribution
by the combinations of the OH vibrations of water molecules, ν3 and ν1. A series of overlapping bands around 4500 and 4100
cm–1 is the result of the combination of the vibrational modes of (SeO3)2– ion in the minerals.
In order to develop a system for quality and safety evaluation of non-homogenised raw milk using near infrared (NIR)
spectroscopy, two stages of research have been conducted. The first stage was the development of a compact NIR system for measuring the major constituents such as fat and
protein in an aseptic environment. The second stage was the measurement of the total aerobic bacteria count (TBC). In the first stage, two compact sample holders for
commercially-available capped test tube were designed. One system was equipped with an NIRSystem6500 research-type NIR spectrophotometer, hereafter referred to as
MilkSpec-2. The other was equipped with a hand-held NIR spectrophotometer, the FT20, hereafter referred to as MilkSpec-3. For MilkSpec-2, the highly satisfactory results were
obtained with the multiple determination coefficients of determination (R2) = 0.99 and 0.96, and standard errors of prediction (SEP) = 0.03% and 0.07%
for fat and protein, respectively. The results for MilkSpec-3 were also satisfactory but inferior compared with MilkSpec-2; the results were R2 = 0.99 and 0.91
and SEP = 0.06% and 0.08% for fat and protein, respectively. In the following stage, MilkSpec-2 was used for the measurement of TBC in terms of log colony forming units
(CFU) mL–1. In the case of TBC measurements, where the concentration of bacteria itself or its by-products were very low, three kinds of commercial test
tube made of the same kind of glass but differing in diameter were used to identify the appropriate physical pathlength. It was found that the medium sized test tube with an
external diameter of 20 mm provided the best calibration results with R2 = 0.83, SEP = 0.55 log (CFU) mL–1 and the ratio of
standard deviation of reference data in the validation set to SEP (RPD) = 2.33. The analysis of the calibration structure indicated that the information related to
absorptions by bacteria metabolites such as lactic acid, urea and those of the carbon sources such as lactose and protein in milk might play substantial roles in the NIR-TBC
determination.
This paper reports a study carried out to determine the effect of post-filter-drying moisture uptake on the repeatability of NIR
spectroscopy analyses of ewe milk using the dry-extract system for infrared (DESIR). The study assessed the spectral repeatability of the method and the effect of moisture uptake
on that repeatability, using graphical representations and root mean squared (RMS) error between spectra, as well as multivariate Mahalanobis distances (GH
values) and predicted constituent values (protein, fat and dry matter). The spectral repeatability of this method of dried milk analysis using glass-fibre filters was very high, both
spectrally per se [RMS MEAN = 3.914 µlog (1/R) and STD = 4.126 µlog (1/R)] and in terms of NIR spectroscopy prediction of chemical components and
of the Mahalanobis distance. Using a single filter per milk sample is thus considered sufficient to guarantee the required accuracy and precision of the DESIR method. Differences
between spectra due to the presence or absence of air exposure [STD = 6446 µlog (1/R)] were greater than the method repeatability error. Predictions of protein, fat
and dry matter were significantly higher for air-exposed filters, due to moisture uptake; the increase in GH values for air-exposed filters was highly significant, suggesting
that milk samples to be analysed using the DESIR method should be stored in a desiccator after drying and before NIR analysis and not left exposed to air.
In this paper, we describe a methodology based on
imaging system shifting and Fourier transform to recover the spatial distribution of the sensivity of a hyperspectral imaging system. The methodology mainly adresses a
hyperspectral imaging system based on a CCD sensor for proximity image acquisition. The principle is to look several times at the same scene by moving the camera slightly (a few
millimetres) at each acquisition. Thus, it is possible to separate what moves (scene) from what remains fixed (response of the system) using properties of Fourier transform. Tests
on synthetic images have reinforced theorical results on contraints shifts and given good results with more than ten translations. Tests on real and in-laboratory images have
shown the need for accurate determination of translation to avoid some disruptive effects (pattern multiplication). Nevertheless, the results are promising and have shown the
potential of the methodology to correct images from spatial non-uniformity due to the imaging system (radiometric aberration due to the sensor and optic). We notice that such a
methodology remains valid for any imaging system based on a charged-coupled device (CCD) sensor.
