A modification for the calculation of water depth profiles in oil‐treated skin by in vivo confocal Raman microscopy

In this study, an extended calculation method for the determination of the water profiles in oil‐treated skin is proposed, which is based on the calculation of the ratio between the Raman band intensities of water (3350‐3550 cm^?1) and keratin Amide I at 1650 cm^?1. The proposed method is compared with the conventional method based on the ratio of the Raman band intensities of water (3350‐3550 cm^?1) and keratin at 2930 cm^?1. The conventional method creates artifacts in the depth profiles of the water concentration in oil‐treated skin, showing a lower amount of water in the upper and intermediate layers of the stratum corneum, which is due to the superposition of oil‐ and keratin‐related Raman bands at 2930 cm^?1. The proposed extended method shows no artifacts and has the potential to determine the water depth profiles after topical application of formulations on the skin.     

Fourier transform infrared and Raman‐based biochemical profiling of different grades of pure foetal‐type hepatoblastoma

The biomolecular events resulting from the progression of hepatoblastoma remain to be elucidated. Fourier‐transform infrared (FTIR) and Raman spectroscopies are capable of noninvasively and accurately capturing the biochemical properties of biological tissue from its pathological status. Our aim was to probe critial biomolecular changes of liver accompanying the progression of pure foetal hepatoblastoma (PFH) by FTIR and Raman spectroscopies. Herein, biochemical alterations were both evident in the FTIR spectra (regions of 3100‐2800 cm^?1 and 1800‐900 cm^?1) and the Raman spectra (region of 1800‐400 cm^?1) among normal, borderline and malignant liver tissues. Compared with normal tissues, the ratios of protein‐to‐lipid, α‐helix‐to‐β‐sheet, RNA‐to‐DNA, CH3 methyl‐to‐CH2 methylene, glucose‐to‐phospholipids, and unsaturated‐to‐saturated lipids intensities were significantly higher in malignant tissues, while the ratios of RNA‐to‐Amide II, DNA‐to‐Amide II, glycogen‐to‐cholesterol and Amide I‐to‐Amide II intensities were remarkably lower. These biochemical alterations in the transition from normal to malignant have profound implications not only for cyto‐pathological classification but also for molecular understanding of PFH progression. The successive changes of the spectral characteristics have been shown to be consistent with the development of PFH, indicating that FTIR and Raman spectroscopies are excellent tools to interrogate the biochemical features of different grades of PFH.      

Non/mini-invasive monitoring of diabetes-induced myocardial damage by Fourier transform infrared spectroscopy: Evidence from biofluids

Early identification of diabetic cardiomyopathy (DCM) can help clinicians develop targeted treatment plans and forensic pathologists make accurate postmortem diagnoses. In the present study, diabetes-induced metabolic abnormalities in the myocardium and biofluids (plasma, urine, and saliva) of db/db mice of various ages (7, 12, and 21 weeks) were investigated by attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy. The results indicated that the diabetic and control groups had significantly different changes in the function groups of lipids, phosphate macromolecules (mostly nucleic acids), protein compositions and conformations, and carbohydrates (primarily glucose) in the myocardium and biofluids. The prediction model for quantifying DCM severity was developed on db/db mice's myocardial spectra using a genetic algorithm (GA)-partial least squares (PLS) regression method. Following that, the linear correlations between the predicted values for DCM severity and spectra for db/db biofluids were evaluated using the GA-PLS regression algorithm. The results showed there were good linear correlations between the predicted values for DCM severity and spectra for plasma (R² = 0.929), saliva (R² = 0.967), urine (R² = 0.954), and combination of plasma and saliva (R² = 0.980). This study provides a novel perspective on detecting diabetes-related biofluid and cardiac metabolic abnormalities and demonstrates the potential of biofluid infrared spectro-diagnostic models for non/mini-invasive assessment of DCM.     

New insights into hidradenitis suppurativa diagnosis via salivary infrared biosignatures: A pilot study

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease which can lead to a prolonged physical disability. HS diagnosis is exclusively clinical with the absence of biomarkers. Our study aims at assessing the HS-diagnostic potential of infrared spectroscopy from saliva, as a biofluid reflecting the body's pathophysiological state. Infrared spectra from 127 patients (57 HS and 70 non-HS) were processed by multivariate methods: principal component analysis coupled with Kruskal–Wallis or Mann–Whitney tests to identify discriminant spectral wavenumbers and linear discriminant analysis to evaluate the performances of HS-diagnostic approach. Infrared features, mainly in the 1300 cm⁻¹-1600 cm⁻¹ region, were identified as discriminant for HS and prediction models revealed diagnostic performances of about 80%. Tobacco and obesity, two main HS risk factors, do not seem to alter the infrared diagnosis. This pilot study shows the potential of salivary “liquid biopsy” associated to vibrational spectroscopy to develop a personalized medical approach for HS patients' management.     

Infrared spectra of glycosaminoglycans in deuterium oxide and deuterium chloride solution: Quantitative evaluation of uronic acid and acetamidodeoxyhexose moieties

I.r. spectra in the “carbonyl region” (1800-1400 cm^?1) have been obtained for aqueous solutions of a number of glycosaminoglycans and model compounds. In D₂O solution, the uronic carboxylate and acetamido groups absorb at characteristic frequencies (ν_asCOO^?, 1605 ±5; ν₅COO^?, 1420 ±5; Amide I, 1623 ±3; and Amide II, 1480 ±2 cm^?1). In acidic (m DCl) solution, the amide bands remain substantially unmodified, whereas those of the carboxylate anion disappear and are replaced by a single band due to the undissociated carboxyl (νCOOH, 1723 ±3 cm^?1). These bands can be used for quantitative evaluation of the uronic acid and acetamidodeoxyhexose moieties of glycosaminoglycans, using either standard polysaccharides or the corresponding monosaccharides as reference compounds. For D₂O solutions, the absorbances of the carboxylate and acetamido groups have been measured by graphical extrapolation of the corresponding most-intense bands (ν_asCOO^? and Amide I). In DCl, the two analytical bands (νCOOH and Amide I) are well-resolved, and analyses have been performed directly from the absorbances recorded. I.r. data for the uronic acid and 2-acetamido-2-deoxyhexose content of various reference samples of glycosaminoglycans are in reasonable agreement with those expected from the “established” structures, as well as with those obtained by colorimetric and conductimetric methods. When sodium d-glucuronate was used as the reference standard, the i.r. data gave relatively low values for the uronic acid content of heparin. The apparent acid dissociation constants of chondroitin 4-sulfate and heparin were estimated from the absorbance of νCOO^? and/or the νCOOH bands at different pH (pD) values.     

Fiber attenuated total reflection infrared spectroscopy of kidney tissue during live surgery

More than 90% of solid kidney tumors are cancerous and have to be treated by surgical resection where surgical outcomes and patient prognosis are dependent on the tumor discrimination. The development of alternative approaches based on a new generation of fiber attenuated total reflection (ATR) probes could aid tumor identification even under intrasurgical conditions. Herein, fiber ATR IR spectroscopy is employed to distinguish normal and cancerous kidney tissues. Freshly resected tissue samples from 34 patients are investigated under nearly native conditions. Spectral marker bands that allow a reliable discrimination between tumor and normal tissue are identified by a supervised classification algorithm. The absorbance values of the bands at 1025, 1155 and 1240 cm^?1 assigned to glycogen and fructose 1,6‐bisphosphatase are used as the clearest markers for the tissue discrimination. Absorbance threshold values for tumor and normal tissue are determined by discriminant analysis. This new approach allows the surgeon to make a clinical diagnosis.     

Secondary Structural Changes in Globular Protein Induced by a Surfactant: Fourier Self-Deconvolution of FT-IR Spectra

Abstract

Conformational changes in ovalbumin, a globular protein, induced by an anionic surfactant, sodium dodecyl sulfate (SDS), have been monitored by an FT-IR spectrometer using ZnSe cylindrical internal reflection optics which allows high quality IR spectra to be obtained in water solution. The most notable change, on addition of SDS, occurs in the composite band of the Amide I absorption band and the vibrational frequency of the composite C=O bond shifts from 1639 cm^?1 to 1652 cm^?1. On the other hand, the position of the Amide II band remains fairly unchanged.

Comparison of the various peak positions in the deconvoluted spectra for the native protein and the perturbed protein clearly shows the effect of SDS on the secondary structures of the protein. SDS unfolds the protein. It increases the helix content slightly. More importantly, it alters the β sheet structure, destroying it almost completely in the Amide I region, while retaining it in its neighbourhood. In the deconvoluted spectra of the perturbed protein, a band at 1531 cm^?1 indicates generation of some β turns. We used the second derivative of the deconvoluted spectra for fixing positions of minor peaks and shoulders.

The results of this study indicate that the deconvolution of the normal IR spectra, consisting of composite bands, provides evidence for the specific secondary structures in a protein and for the way they are affected by changes in the environment, e.g., the addition of SDS. This makes it possible to relate conformational changes to specific secondary structures.     

Synchrotron-based FTIR microspectroscopy of chili resistance induced by Bacillus subtilis strain D604 against anthracnose disease

The aim of this study was to determine the resistance mechanisms of chili induced by the Bacillus subtilis strain D604 using synchrotron FTIR microspectroscopy (SR-FTIR). In this study, the strain D604 reduced anthracnose disease severity in chili plants by approximately 31.10%. The SR-FTIR spectral changes from the epidermis and mesophyll leaf tissue revealed higher integral areas for the C=O ester from lipids, lignin, or pectin (1770–1700?cm^?1) as well as polysaccharides (1200–900?cm^?1) in the treated samples of D606 and distilled water and then challenge inoculation with chili anthracnose pathogen, Colletotrichum acutatum. The secondary structure of the Amide I protein failed to convert from alpha helices (centered at 1650?cm^?1) to beta sheets (centered at 1600?cm^?1) in the mesophyll of samples not treated with D604. This study suggested that the strain D604 induced resistance against anthracnose pathogen in chili by inducing cellular changes related to defense compounds involved in plant defense mechanism.     

Discriminant analysis and its application in DNA sequence motif recognition

Identification of functional motifs in a DNA sequence is fundamentally a statistical pattern recognition problem. Discriminant analysis is widely used for solving such problems. This paper will review two basic parametric methods: LDA (linear discriminant analysis) and QDA (quadratic discriminant analysis). Their usage in recognition of splice sites and exons in the human genome will be demonstrated.     

Two classification methods for developing and interpreting productivity zones using site properties

Crop performance is often shown as areas of differing grain yield. Many producers utilize simple GIS color ramping techniques to produce visual yield maps with delineated clusters. However, a more quantitative approach such as an unsupervised clustering procedure is generally used by scientists since it is much less arbitrary. Intuitively the yield clusters are due to soil and terrain properties, but there is no clear criterion for the delineation. We compared the effectiveness of two delineation or classification procedures: quadratic discriminant analysis (QDA) and k-nearest neighbor discriminant analysis (k-NN) for the study of how yield temporal patterns relate to site properties. This study used three production fields, one in Monticello, IL, and two in Centralia, MO. Clusters were defined using maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) yield from three seasons. The k-NN had greater and more consistent successful classification rates than did QDA. Classification success rate varied from 0.465 to 0.790 for QDA while the k-NN classification rate varied from 0.794 to 0.874. This shows that areas of certain temporal yield patterns correspond to areas of specific site properties. Although profiles of site properties differ by crop and production field, areas of consistent low maize yield had greater shallow electrical conductivity (EC_shallow), than those of consistent high maize yield. Furthermore, areas of consistent high soybean yield had lower soil reflectance than those areas of consistent low yields.     

The structural analysis of three‐dimensional fibrous collagen hydrogels by raman microspectroscopy

To investigate molecular effects of 1‐Ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC), EDC/N‐hydroxysuccinimide (NHS), glyceraldehyde cross‐linking as well as polymerization temperature and concentration on the three‐dimensional (3D) collagen hydrogels, we analyzed the structures in situ by Raman microspectroscopy. The increased intensity of the 814 and 936 cm^?1 Raman bands corresponding to the C—C stretch of a protein backbone and a shift in the amide III bands from 1241 cm^?1/1268 cm^?1 in controls to 1247 cm^?1/1283 cm^?1 in glyceraldehyde‐treated gels indicated changes to the alignment of the collagen molecules, fibrils/fibers and/or changes to the secondary structure on glyceraldehyde treatment. The increased intensity of 1450 cm^?1 band and the appearance of a strong peak at 1468 cm^?1 reflected a change in the motion of lysine/arginine CH₂ groups. For the EDC‐treated collagen hydrogels, the increased intensity of 823 cm^?1 peak corresponding to the C—C stretch of the protein backbone indicated that EDC also changed the packing of collagen molecules. The 23% decrease in the ratio of 1238 cm^?1 to 1271 cm^?1 amide III band intensities in the EDC‐modified samples compared with the controls indicated changes to the alignment of the collagen molecules/fibrils and/or the secondary structure. A change in the motion of lysine/arginine CH₂ groups was detected as well. The addition of NHS did not induce additional Raman shifts compared to the effect of EDC alone with the exception of a 1416 cm^?1 band corresponding to a COO^? stretch. Overall, the Raman spectra suggest that glyceraldehyde affects the collagen states within 3D hydrogels to a greater extent compared to EDC and the effects of temperature and concentration are minimal and/or not detectable. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 349–356, 2013.     

Stereological estimation of the surface area and oxygen diffusing capacity of the respiratory stomach of the air‐breathing armored catfish Pterygoplichthys anisitsi (Teleostei: Loricariidae)

The stomach of Pterygoplichthys anisitsi has a thin, translucent wall and a simple squamous epithelium with an underlying dense capillary network. In the cardiac and pyloric regions, most cells have short microvilli distributed throughout the cell surface and their edges are characterized by short, densely packed microvilli. The mucosal layer of the stomach has two types of pavement epithelial cells that are similar to those in the aerial respiratory organs. Type 1 pavement epithelial cells, resembling the Type I pneumocyte in mammal lungs, are flat, with a large nucleus, and extend a thin sheet of cytoplasm on the underlying capillary. Type 2 cells, resembling the Type II pneumocyte, possess numerous mitochondria, a well‐developed Golgi complex, rough endoplasmic reticulum, and numerous lamellar bodies in different stages of maturation. The gastric glands, distributed throughout the mucosal layer, also have several cells with many lamellar bodies. The total volume (air + tissue), tissue, and air capacity of the stomach when inflated, increase along with body mass. The surface‐to‐tissue‐volume ratio of stomach varies from 108 cm^?1 in the smallest fish (0.084 kg) to 59 cm^?1 in the largest fish (0.60 kg). The total stomach surface area shows a low correlation to body mass. Nevertheless, the body‐mass‐specific surface area varied from 281.40 cm² kg^?1 in the smallest fish to 68.08 cm² kg^?1 in the largest fish, indicating a negative correlation to body mass (b = ?0.76). The arithmetic mean barrier thickness between air and blood was 1.52 ± 0.07 μm, whereas the harmonic mean thickness (τ_h) of the diffusion barrier ranged from 0.40 to 0.74 μm. The anatomical diffusion factor (ADF = cm² μm^?1 kg^?1) and the morphological O₂ diffusion capacity (D_morpholO₂ = cm³ min^?1 mmHg^?1 kg^?1) are higher in the smallest specimen and lower in the largest one. In conclusion, the structure and morphometric data of P. anisitsi stomach indicate that this organ is adapted for oxygen uptake from air. J. Morphol. 2009. © 2008 Wiley‐Liss, Inc.     

Sialolithiasis: Application parameters for an optimal laser therapy

In‐vitro experimental parametric studies of laser ablation using natural sialoliths and artificial stones have been performed toward an efficient laser treatment of sialolithiasis. Surface microstructure and water adsorption become critical for coupling high power pulsed Ho:YAG laser radiation (λ = 2080 nm, τ ～250 μsec), inducing ablative interactions and stone fragmentation. Results reveal a generic trend, with single pulse laser energy density threshold for sialolith ablative erosion at ～200 J cm^?2 (corresponding to intensity ～800 kW cm^?2) and fragmentation rates reaching ～1 mm/pulse at ～2400 J cm^?2. This process shows no saturation, suggesting that very high energy density irradiation at low pulse repetition rate is an efficient approach. Such operation facilitates rapid cooling and minimal thermal loading of the oral and maxillofacial area, thus causing negligible adverse effects. The method is expected to contribute to the establishment of an easy and optimal therapeutic protocol for sialolithiasis pathology.     

Characterisation of DNA methylation status using spectroscopy (mid‐IR versus Raman) with multivariate analysis

Methylation status plays important roles in the regulation of gene expression and significantly influences the dynamics, bending and flexibility of DNA. The aim of this study was to determine whether attenuated total reflection Fourier‐transform infrared (ATR‐FTIR) or Raman spectroscopy with subsequent multivariate analysis could determine methylation patterning in oligonucleotides variously containing 5‐methylcytosine, cytosine and guanine bases. Applied to Low‐E reflective glass slides, 10 independent spectral acquisitions were acquired per oligonucleotide sample. Resultant spectra were baseline‐corrected and vector normalised over the 1750 cm^–1–760 cm^–1 (for ATR‐FTIR spectroscopy) or the 1750 cm^–1–600 cm^–1 (for Raman spectroscopy) regions. Data were then analysed using principal component analysis (PCA) coupled with linear discriminant analysis (LDA). Exploiting this approach, biomolecular signatures enabling sensitive and specific discrimination of methylation patterning were derived. For DNA sequence and methylation analysis, this approach has the potential to be an important tool, especially when material is scarce. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Robust discriminant analysis and its application to identify protein coding regions of rice genes

Identification of protein coding regions is fundamentally a statistical pattern recognition problem. Discriminant analysis is a statistical technique for classifying a set of observations into predefined classes and it is useful to solve such problems. It is well known that outliers are present in virtually every data set in any application domain, and classical discriminant analysis methods (including linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA)) do not work well if the data set has outliers. In order to overcome the difficulty, the robust statistical method is used in this paper. We choose four different coding characters as discriminant variables and an approving result is presented by the method of robust discriminant analysis.     

Exploration research on the fusion of multimodal spectrum technology to improve performance of rapid diagnosis scheme for thyroid dysfunction

The spectral fusion by Raman spectroscopy and Fourier infrared spectroscopy combined with pattern recognition algorithms is utilized to diagnose thyroid dysfunction serum, and finds the spectral segment with the highest sensitivity to further advance diagnosis speed. Compared with the single infrared spectroscopy or Raman spectroscopy, the proposal can improve the detection accuracy, and can obtain more spectral features, indicating greater differences between thyroid dysfunction and normal serum samples. For discriminating different samples, principal component analysis (PCA) was first used for feature extraction to reduce the dimension of high‐dimension spectral data and spectral fusion. Then, support vector machine (SVM), back propagation neural network, extreme learning machine and learning vector quantization algorithms were employed to establish the discriminant diagnostic models. The accuracy of spectral fusion of the best analytical model PCA‐SVM, single Raman spectral accuracy and single infrared spectral accuracy is 83.48%, 78.26% and 80%, respectively. The accuracy of spectral fusion is higher than the accuracy of single spectrum in five classifiers. And the diagnostic accuracy of spectral fusion in the range of 2000 to 2500 cm^?1 is 81.74%, which greatly improves the sample measure speed and data analysis speed than analysis of full spectra. The results from our study demonstrate that the serum spectral fusion technique combined with multivariate statistical methods have great potential for the screening of thyroid dysfunction.     

3D Printing of Tunable Energy Storage Devices with Both High Areal and Volumetric Energy Densities

Developing advanced supercapacitors with both high areal and volumetric energy densities remains challenging. In this work, self‐supported, compact carbon composite electrodes are designed with tunable thickness using 3D printing technology for high‐energy‐density supercapacitors. The 3D carbon composite electrodes are composed of the closely stacked and aligned active carbon/carbon nanotube/reduced graphene oxide (AC/CNT/rGO) composite filaments. The AC microparticles are uniformly embedded in the wrinkled CNT/rGO conductive networks without using polymer binders, which contributes to the formation of abundant open and hierarchical pores. The 3D‐printed ultrathick AC/CNT/rGO composite electrode (ten layers) features high areal and volumetric mass loadings of 56.9 mg cm^?2 and 256.3 mg cm^?3, respectively. The symmetric cell assembled with the 3D‐printed thin GO separator and ultrathick AC/CNT/rGO electrodes can possess both high areal and volumetric capacitances of 4.56 F cm^?2 and 10.28 F cm^?3, respectively. Correspondingly, the assembled ultrathick and compact symmetric cell achieves high areal and volumetric energy densities of 0.63 mWh cm^?2 and 1.43 mWh cm^?3, respectively. The all‐component extrusion‐based 3D printing offers a promising strategy for the fabrication of multiscale and multidimensional structures of various high‐energy‐density electrochemical energy storage devices.     

Hierarchical Zn–Co–S Nanowires as Advanced Electrodes for All Solid State Asymmetric Supercapacitors

A facile two‐step strategy is developed to design the large‐scale synthesis of hierarchical, unique porous architecture of ternary metal hydroxide nanowires grown on porous 3D Ni foam and subsequent effective sulfurization. The hierarchical Zn–Co–S nanowires (NWs) arrays are directly employed as an electrode for supercapacitors application. The as‐synthesized Zn–Co–S NWs deliver an ultrahigh areal capacity of 0.9 mA h cm^?2 (specific capacity of 366.7 mA h g^?1) at a current density of 3 mA cm^?2, with an exceptional rate capability (≈227.6 mA h g^?1 at a very high current density of 40 mA cm^?2) and outstanding cycling stability (≈93.2% of capacity retention after 10 000 cycles). Most significantly, the assembled Zn–Co–S NWs//Fe₂O₃@reduced graphene oxide asymmetric supercapacitors with a wide operating potential window of ≈1.6 V yield an ultrahigh volumetric capacity of ≈1.98 mA h cm^?3 at a current density of 3 mA cm^?2, excellent energy density of ≈81.6 W h kg^?1 at a power density of ≈559.2 W kg^?1, and exceptional cycling performance (≈92.1% of capacity retention after 10 000 cycles). This general strategy provides an alternative to design the other ternary metal sulfides, making it facile, free‐standing, binder‐free, and cost‐effective ternary metal sulfide‐based electrodes for large‐scale applications in modern electronics.     

Directed evolution of Aspergillus niger glucoamylase to increase thermostability

Using directed evolution and site‐directed mutagenesis, we have isolated a highly thermostable variant of Aspergillus niger glucoamylase (GA), designated CR2‐1 . CR2‐1 includes the previously described mutations Asn20Cys and Ala27Cys (forming a new disulfide bond), Ser30Pro, Thr62Ala, Ser119Pro, Gly137Ala, Thr290Ala, His391Tyr and Ser436Pro. In addition, CR2‐1 includes several new putative thermostable mutations, Val59Ala, Val88Ile, Ser211Pro, Asp293Ala, Thr390Ser, Tyr402Phe and Glu408Lys, identified by directed evolution. CR2‐1 GA has a catalytic efficiency (k_cat/K_m) at 35°C and a specific activity at 50°C similar to that of wild‐type GA. Irreversible inactivation tests indicated that CR2‐1 increases the free energy of thermoinactivation at 80°C by 10 kJ mol^?1 compared with that of wild‐type GA. Thus, CR2‐1 is more thermostable (by 5 kJ mol^?1 at 80°C) than the most thermostable A. niger GA variant previously described, THS8 . In addition, Val59Ala and Glu408Lys were shown to individually increase the thermostability in GA variants by 1 and 2 kJ mol^?1, respectively, at 80°C.     

Complex biopolymeric systems at stalk/epicuticular wax plant interfaces: A near infrared spectroscopy study of the sugarcane example

Naturally occurring macromolecules present at the epicuticular wax/stalk tissue interface of sugarcane were investigated using near infrared spectroscopy (NIRS). Investigations of water, cellulose, and wax‐cellulose interrelationships were possible using NIRS methods, where in the past many different techniques have been required. The sugarcane complex interface was used as an example of typical phenomena found at plant leaf/stalk interfaces. This detailed study showed that sugarcane cultivars exhibit spectral differences in the CH_n, water OH, and cellulose OH regions, reflecting the presence of epicuticular wax, epidermis, and ground tissue. Spectrally complex water bands (5276 cm^?1 and 7500–6000 cm^?1) were investigated via freeze‐drying experiments which revealed sequentially a complex band substructure (7500–6000 cm^?1), a developing weak H‐bonding system (～7301 cm^?1), and strong H‐bonding (～7062 cm^?1) assigned to water—cellulose interactions. Principal component analysis techniques clarified complex band trends that developed during the desorption experiment. Bands from wax‐free stalk were minimized in the 4327–4080 cm^?1 region (C? H_n vibrational modes associated with long chain fatty compounds), while bands from the stalk tissue (particularly lignin and moisture) became more pronounced. This work is a comprehensive guide to similar studies by scientists involved in a variety of plant and fiber research fields. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 642–651, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com