Fourier transform infrared microspectroscopy as a tool to identify macroalgal propagules

Understanding of macroalgal dispersal has been hindered by the difficulty in identifying propagules. Different carrageenans typically occur in gametophytes and tetrasporophytes of the red algal family Gigartinaceae, and we may expect that carpospores and tetraspores also differ in composition of carrageenans. Using Fourier transform infrared (FT-IR) microspectroscopy, we tested the model that differences in carrageenans and other cellular constituents between nuclear phases should allow us to discriminate carpospores and tetraspores of Chondrus verrucosus Mikami. Spectral data suggest that carposporophytes isolated from the pericarp and female gametophytes contained κ-carrageenan, whereas tetrasporophytes contained λ-carrageenan. However, both carpospores and tetraspores exhibited absorbances in wave bands characteristic of κ-,ι-, and λ-carrageenans. Carpospores contained more proteins and may be more photosynthetically active than tetraspores, which contained more lipid reserves. We draw analogies to planktotrophic and lecithotrophic larvae. These differences in cellular chemistry allowed reliable discrimination of spores, but pretreatment of spectral data affected the accuracy of classification. The best classification of spores was achieved with extended multiplicative signal correction (EMSC) pretreatment using partial least squares discrimination analysis, with correct classification of 86% of carpospores and 83% of tetraspores. Classification may be further improved by using synchrotron FT-IR microspectroscopy because of its inherently higher signal-to-noise ratio compared with microspectroscopy using conventional sources of IR. This study demonstrates that FT-IR microspectroscopy and bioinformatics are useful tools to advance our understanding of algal dispersal ecology through discrimination of morphologically similar propagules both within and potentially between species.

Quantitative determination of fatty acid compositions in micro-encapsulated fish-oil supplements using Fourier transform infrared (FTIR) spectroscopy

The research describes a rapid method for the determination of fatty acid (FA) contents in a micro-encapsulated fish-oil (μEFO) supplement by using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic technique and partial least square regression (PLSR) analysis. Using the ATR-FTIR technique, the μEFO powder samples can be directly analysed without any pre-treatment required, and our developed PLSR strategic approach based on the acquired spectral data led to production of a good linear calibration with R^₂ = 0.99. In addition, the subsequent predictions acquired from an independent validation set for the target FA compositions (i.e., total oil, total omega-3 fatty acids, EPA and DHA) were highly accurate when compared to the actual values obtained from standard GC-based technique, with plots between predicted versus actual values resulting in excellent linear fitting (R² ⩾ 0.96) in all cases. The study therefore demonstrated not only the substantial advantage of the ATR-FTIR technique in terms of rapidness and cost effectiveness, but also its potential application as a rapid, potentially automated, online monitoring technique for the routine analysis of FA composition in industrial processes when used together with the multivariate.

Attenuated total reflectance fourier transform infrared spectroscopy: an analytical technique to understand therapeutic responses at the molecular level

Rapid monitoring of the response to treatment in cancer patients is essential to predict the outcome of the therapeutic regimen early in the course of the treatment. The conventional methods are laborious, time-consuming, subjective and lack the ability to study different biomolecules and their interactions, simultaneously. Since; mechanisms of cancer and its response to therapy is dependent on molecular interactions and not on single biomolecules, an assay capable of studying molecular interactions as a whole, is preferred. Fourier Transform Infrared (FTIR) spectroscopy has become a popular technique in the field of cancer therapy with an ability to elucidate molecular interactions. The aim of this study, was to explore the utility of the FTIR technique along with multivariate analysis to understand whether the method has the resolution to identify the differences in the mechanism of therapeutic response. Towards achieving the aim, we utilized the mouse xenograft model of retinoblastoma and nanoparticle mediated targeted therapy. The results indicate that the mechanism underlying the response differed between the treated and untreated group which can be elucidated by unique spectral signatures generated by each group. The study establishes the efficiency of non-invasive, label-free and rapid FTIR method in assessing the interactions of nanoparticles with cellular macromolecules towards monitoring the response to cancer therapeutics.

Characterization of hot-pressed films from superfine wool powder

In this study, superfine wool powder was plasticized with glycerol and hot-pressed into a film. Scanning electron microscopy photos showed that the superfine wool powder could be molded into a smooth film and that the wool powder was distributed evenly in the cross section of the film. Fourier transform infrared analysis revealed no substantial changes in the chemical structure of the wool powder after hot pressing, but the absorbing peaks of glycerol were found in the spectrum. X-ray diffraction analysis showed that the overall crystallinity increased after the wool powder was hot-pressed into film. Thermogravimetry (TG) analysis indicated that the thermal stability of the hot-pressed film decreased. A transition point appeared in the TG curve of the wool hot-pressed film as glycerol was added. The differential thermal analysis curve of the film showed sharp absorbing peaks similar to that of wool powder. With increasing glycerol content, the film showed increasing ductility and softness.

Electrochemical impedance spectroscopy and surface characterization techniques to study carbon dioxide corrosion product scales

Electrochemical impedance spectroscopy (EIS) was used to study carbon dioxide (CO2) corrosion product scales and their effects on further CO2 corrosion. Objectives were to determine the suitability of EIS for studying corrosion scales and to investigate the influence of environmental factors on scale formation. EIS provided useful information about protective abilities and electrochemical properties of corrosion scales. CO2 corrosion scales formed at high-temperature and pressure provided better protection than those formed at low-temperature and pressure. The level of protection of the scale formed at higher temperature and pressure increased with exposure time. EIS results were compared with coupon weight-loss measurements. Scales were analyzed using a combination of Fourier transform infrared (FTIR) analysis, x-ray diffraction (XRD), and electron microscopy.

Studies of CO2 corrosion product scales using electrochemical impedance spectroscopy and surface characterisation techniques

Electrochemical impedance spectroscopy (EIS) was used to study carbon dioxide (CO2) corrosion product scales and their effects on further CO2 corrosion. Objectives were to determine the suitability of EIS for studying corrosion scales and to investigate the influence of environmental factors on scale formation. EIS provided useful information about protective abilities and electrochemical properties of corrosion scales. CO2 corrosion scales formed at high-temperature and pressure provided better protection than those formed at low-temperature and pressure. The level of protection of the scale formed at higher temperature and pressure increased with exposure time. EIS results were compared with coupon weight-loss measurements. Scales were analyzed using a combination of Fourier transform infrared (FTIR) analysis, x-ray diffraction (XRD), and electron microscopy

FTIR and thermal analysis of cashmere and other animal fibres

In this paper, sereval varieties of animal fibres including cashmere and Australian fine Merino wool have been analysed by Fourier transform infrared microscope and differential scanning calorimeter. The results showed that both Chinese and Australian cashmere fibres started absorbing heat at a relatively higher temperature but were thermally degraded quicker than other animal fibres tested. However, the mass changes (within the temperature range of 200oC to 350oC) and associated onset temperatures varied among fibre varieties. From the attenuated total reflectance spectra, the Chinese cashmere was clearly different from Australian cashmere and wool in a peak near 1040 cm-1 wavelength for S-O stretching of cysteic acid residues. The Chinese cashmere presented a stronger absorption at 1019 cm-1 wavelength, while Australian cashmere and wool peaked at 1079 cm-1 wavelength and had a weaker absorption. Combined with thermal analysis, the normalised R-SO3 - content of cysteic acid residues to the amide II peak of the protein backbone may have potential use in identifying Australian fine Merino wool from Chinese cashmere.

Molecular identification of marine yeast and its spectroscopic analysis establishes unsaturated fatty acid accumulation

Marine microbes are competent organisms, some of which can accumulate large amounts of lipids. A yeast strain, Rhodotorula mucilaginosa AMCQ8A was isolated from the marine water of the Queenscliff region, Victoria, Australia. The yeast isolate was identified by sequencing 18s rDNA genes. Scanning electron microscopy images revealed scars on the surface of the yeast cells. The Fourier transform infrared spectroscopy microspectroscopy studies demonstrated the presence of unsaturated fatty acids by differential microscopic analysis. The sharp band at 1745 cm^-1 was represented by ν(C=O) stretches of ester functional groups from lipids and fats, and therefore indicated the presence of total lipids produced by the cells. Over 65% of the fatty acids from the yeast strain were analyzed as C¹⁶ and C^18:1 with omega-3 content from about 6% to 7%. Thus, this marine-derived yeast could be a potential source of lipids, including omega-3 fatty acids. 2012, The Society for Biotechnology, Japan. All rights reserved.

Rapid determination of protein contents in microencapsulated fish oil supplements by ATR-FTIR spectroscopy and partial least square regression (PLSR) analysis

Following the recent success in quantitative analysis of essential fatty acid compositions in a commercial microencapsulated fish oil (?EFO) supplement, we extended the application of portable attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic technique and partial least square regression (PLSR) analysis for rapid determination of total protein contents-the other major component in most commercial ?EFO powders. In contrast to the traditional chromatographic methodology used in a routine amino acid analysis (AAA), the ATR-FTIR spectra of the ?EFO powder can be acquired directly from its original powder form with no requirement of any sample preparation, making the technique exceptionally fast, noninvasive, and environmentally friendly as well as being cost effective and hence eminently suitable for routine use by industry. By optimizing the spectral region of interest and number of latent factors through the developed PLSR strategy, a good linear calibration model was produced as indicated by an excellent value of coefficient of determination R2 = 0.9975, using standard ?EFO powders with total protein contents in the range of 140-450 mg/g. The prediction of the protein contents acquired from an independent validation set through the optimized PLSR model was highly accurate as evidenced through (1) a good linear fitting (R2 = 0.9759) in the plot of predicted versus reference values, which were obtained from a standard AAA method, (2) lowest root mean square error of prediction (11.64 mg/g), and (3) high residual predictive deviation (6.83) ranked in very good level of predictive quality indicating high robustness and good predictive performance of the achieved PLSR calibration model. The study therefore demonstrated the potential application of the portable ATR-FTIR technique when used together with PLSR analysis for rapid online monitoring of the two major components (i.e., oil and protein contents) in finished ?EFO powders in the actual manufacturing setting.

Rapid discrimination and determination of polyunsaturated fatty acid composition in marine oils by FTIR Spectroscopy and Multivariate Data Analysis

A rapid analytical approach for discrimination and quantitative determination of polyunsaturated fatty acid (PUFA) contents, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in a range of oils extracted from marine resources has been developed by using attenuated total reflection Fourier transform infrared spectroscopy and multivariate data analysis. The spectral data were collected without any sample preparation; thus, no chemical preparation was involved, but data were rather processed directly using the developed spectral analysis platform, making it fast, very cost effective, and suitable for routine use in various biotechnological and food research and related industries. Unsupervised pattern recognition techniques, including principal component analysis and unsupervised hierarchical cluster analysis, discriminated the marine oils into groups by correlating similarities and differences in their fatty acid (FA) compositions that corresponded well to the FA profiles obtained from traditional lipid analysis based on gas chromatography (GC). Furthermore, quantitative determination of unsaturated fatty acids, PUFAs, EPA and DHA, by partial least square regression analysis through which calibration models were optimized specifically for each targeted FA, was performed in both known marine oils and totally independent unknown n - 3 oil samples obtained from an actual commercial product in order to provide prospective testing of the developed models towards actual applications. The resultant predicted FAs were achieved at a good accuracy compared to their reference GC values as evidenced through (1) low root mean square error of prediction, (2) good coefficient of determination close to 1 (i.e., R 2≥ 0.96), and (3) the residual predictive deviation values that indicated the predictive power at good and higher levels for all the target FAs. © 2014 Springer Science+Business Media New York.

Synchrotron-FTIR microspectroscopy enables the distinction of lipid accumulation in thraustochytrid strains through analysis of individual live cells

The superior characteristics of high photon flux and diffraction-limited spatial resolution achieved by synchrotron-FTIR microspectroscopy allowed molecular characterization of individual live thraustochytrids. Principal component analysis revealed distinct separation of the single live cell spectra into their corresponding strains, comprised of new Australasian thraustochytrids (AMCQS5-5 and S7) and standard cultures (AH-2 and S31). Unsupervised hierarchical cluster analysis (UHCA) indicated close similarities between S7 and AH-7 strains, with AMCQS5-5 being distinctly different. UHCA correlation conformed well to the fatty acid profiles, indicating the type of fatty acids as a critical factor in chemotaxonomic discrimination of these thraustochytrids and also revealing the distinctively high polyunsaturated fatty acid content as key identity of AMCQS5-5. Partial least squares discriminant analysis using cross-validation approach between two replicate datasets was demonstrated to be a powerful classification method leading to models of high robustness and 100% predictive accuracy for strain identification. The results emphasized the exceptional S-FTIR capability to perform real-time in vivo measurement of single live cells directly within their original medium, providing unique information on cell variability among the population of each isolate and evidence of spontaneous lipid peroxidation that could lead to deeper understanding of lipid production and oxidation in thraustochytrids for single-cell oil development.

Investigation of failure mechanisms in aged aerospace composites

The effect of isothermal ageing on two high temperature, bismaleimide composite materials, a novel CSIRO CBR 320/328 composite and a commercial CIBA GEIGY Matrimid® 5292 composite, was examined at 204 and 250 °C. Delamination is a major cause of failure in composite materials, therefore, the Mode I interlaminar fracture toughness (GIC) of both materials was measured using the double cantilever beam (DCB) test. Chemical degradation of the matrix was monitored concurrently using Fourier transform infrared (FTIR) and Raman spectroscopy. Chemical changes at the core of both of these materials were found to occur concomitantly with the observed changes in interlaminar fracture toughness. FTIR analysis of both matrix materials revealed the predominant degradation mechanism to be the oxidation of the methylene group bridging two aromatic rings common to the structure of both resins, and was substantiated by the ingrowth of a broad peak centred at 1600 cm⁻¹ . In addition to this, the pyromellitic anhydride unit present only in the CBR 320/328 composites was found to be highly resistant to the effects of ageing, whereas the saturated imide, common to the cured structures of both materials, was observed to degrade. Raman spectroscopy indicated that the predominant degradation mechanism of the composites differed at the two ageing temperatures.

Determination of cashmere and wool fibre scale frequency by analysing diameter profiles with fast fourier transform

This paper describes a potentially faster and cheaper method of determining fibre scale frequencies. The method uses the single fibre analyser (SIFAN) to  determine the along the fibre diameter profile. This information is then analysed by the Fast Fourier Transform technique using computer software. The paper shows the close association between the mean scale frequencies determined by this method and the traditional approach using SEM.

Manufacturing process effects on the mode I interlaminar fracture toughness and nanocreep properties of CFRP

Quickstep ™ is a fluid filled floating mould technology which was recently developed by an Australian company of the same name. The Quickstep and conventional autoclave manufacture of composites were compared by investigating the mode I interlaminar fracture toughness and nanocreep propeties of HexPly914 carbon epoxy composites. It was found that composites cured using the Quickstep technology had significantly higher fracture toughness (1.8 times) than the composites cured via autoclave for this system. DMTA (dynamic mechanical thermal analysis) results showed a higher Tg (glass transition temperature) for the material manufactured by the Quickstep than that cured by the autoclave. FTIR (Fourier transform infrared spectroscopy) spectra did not indicate any difference in cure chemistry between the two processes. Nanocreep experiments were performed to explore the viscoelastic properties of the epoxy matrix of composites. The KelvinVoigt three-element model was applied to analyse the indentation creep behaviour of both composites.