Monitoring of the natural aging of Diclofenac tablets, NIR and MIR-ATR spectroscopy coupled with chemometrics data analysis.

This study presents the analysis of the natural long-term aging of both the intact tablets and the active pharmaceutical ingredient. No forced aging conditions were applied to the samples. It is shown that the near infrared spectroscopy of the intact tablets packed in plastic blisters, supported by chemometrics, is a reliable method for detection of even slight deviations of the medicine from its regular state. Independent components analysis helps to extract source signals from spectra of the composite object "a coated tablet sealed in polyvinylchloride blister". Further analysis of the near infrared and attenuated total reflectance infrared spectra of the pure substance confirmed that the aging process detected by the analysis of the intact tablets is directly related to the degradation of the active pharmaceutical ingredient.

Evaluation of the impact of buffered peptone water composition on the discrimination between Salmonella enterica and Escherichia coli by Raman spectroscopy.

The detection of Salmonella spp. in food samples is regulated by the ISO 6579:2002 standard, which requires that precise procedures are followed to ensure the reliability of the detection process. This standard requires buffered peptone water as a rich medium for the enrichment of bacteria. However, the effects of different brands of buffered peptone water on the identification of microorganisms by Raman spectroscopy are unknown. In this regard, our study evaluated the discrimination between two bacterial species, Salmonella enterica and Escherichia coli, inoculated and analyzed with six of the most commonly used buffered peptone water brands. The results showed that bacterial cells behaved differently according to the brand used in terms of biomass production and the spectral fingerprint. The identification accuracy of the analyzed strains was between 85% and 100% depending on the given brand. Several batches of two brands were studied to evaluate the classification rates between the analyzed bacterial species. The chemical analysis performed on these brands showed that the nutrient content was slightly different and probably explained the observed effects. On the basis of these results, Raman spectroscopy operators are encouraged to select an adequate culture medium and continue its use throughout the identification process to guarantee optimal recognition of the microorganism of interest.

ComDim for explorative multi-block data analysis of Cantal-type cheeses: Effects of salts, gentle heating and ripening.

Common Dimension (ComDim) chemometrics method for multi-block data analysis was employed to evaluate the impact of different added salts and ripening times on physicochemical, color, dynamic low amplitude oscillatory rheology, texture profile, and molecular structure (fluorescence and MIR spectroscopies) of five Cantal-type cheeses. Firstly, Independent Components Analysis (ICA) was applied separately on fluorescence and MIR spectra in order to extract the relevant signal source and the associated proportions related to molecular structure characteristics. ComDim was then applied on the 31 data tables corresponding to the proportion of ICA signals obtained for spectral methods and the global analysis of cheeses by the other techniques. The ComDim results indicated that generally cheeses made with 50% NaCl or with 75:25% NaCl/KCl exhibit the equivalent characteristics in structural, textural, meltability and color properties. The proposed methodology demonstrates the applicability of ComDim for the characterization of samples when different techniques describe the same samples.

Highlighting metabolic indicators of olive oil during storage by the AComDim method.

Lipid oxidation during olive oil storage induces changes in the metabolite content of the oil, which can be measured using so-called quality indices. High values indicate poor quality oils that should be labeled accordingly or removed from the market. Based on quality indices measured over two years for two olive oils, the AComDim method was used to highlight the influence of five factors (olive oil type, oxygen, light, temperature and storage time) on oxidative stability during storage. To identify the significant factors, two full factorial experimental designs were built, each containing four of the five factors examined. The results showed that all five factors, as well as some two-factor interactions, were significant. Phenols and hydroperoxides were identified as being the most sensitive to these factors, and potential markers for the ageing of olive oil.

Development of a percutaneous penetration predictive model by SR-FTIR.

This work focused on developing a new evaluation criterion of percutaneous penetration, in complement to Log Pow and MW and based on high spatial resolution Fourier transformed infrared (FTIR) microspectroscopy with a synchrotron source (SR-FTIR). Classic Franz cell experiments were run and after 22 h molecule distribution in skin was determined either by HPLC or by SR-FTIR. HPLC data served as reference. HPLC and SR-FTIR results were compared and a new predictive criterion based from SR-FTIR results, named S(index), was determined using a multi-block data analysis technique (ComDim). A predictive cartography of the distribution of molecules in the skin was built and compared to OECD predictive cartography. This new criterion S(index) and the cartography using SR-FTIR/HPLC results provides relevant information for risk analysis regarding prediction of percutaneous penetration and could be used to build a new mathematical model.

A multiway chemometric and kinetic study for evaluating the thermal stability of edible oils by ¹H NMR analysis: comparison of methods.

The degradation process of edible oils of different nature, submitted to heating at 170°C, 190°C and 210°C with aeration, was studied by means of (1)H nuclear magnetic resonance spectroscopy (NMR). In this study, secondary products such as aldehydes were detected and monitored over time. Two complementary analytical approaches were adopted to characterize the kinetics of the appearance of aldehydes in the heated oils. This first was a classical kinetic approach based on the assumption that the overall degradation reaction to form aldehydes follows a rate law of order 1. This approach allowed us to calculate a thermal stability criterion for classifying the oils according to their heat stability. A second approach was to use the spectral fingerprint corresponding to aldehydes in a multivariate data analysis procedure in order to give the major trend in the studied phenomena, taking into account the multiway nature of recorded data. The application of different 3-way and 4-way Tucker3 models led to a better understanding of the chemical stability of the oils studied and was used to determine the order of stability of these oils. This multiway approach provides additional information that 2-way processing (PCA) does not provide clearly, such as the overall contribution of the heating time factor on the chemical evolution of oils. In conclusion, this work shows that a fully chemometric study of NMR spectra allows to order the oils according to their thermal stability and to achieve a result in good agreement with existing analytical and kinetic studies in the literature.

Development of near infrared sensors: detection of influential factors by the AComDim method.

The development of near infrared (NIR) sensors has to go through different steps of testing. Once a prototype is ready to be used, it is necessary to evaluate and optimize the experimental conditions and the data collection, in terms of accuracy, repeatability, reproducibility and speed. This paper studies the effects of controllable experimental factors on the quality of the spectral response, to determine the influence of each instrumental parameter and to improve the predictions obtained from the collected data. The AComDim method, based on the multi-block analysis of ANOVA matrices, was used here to evaluate the impact of experimental factors on the responses from the different sensors tested.

Improving the detection of significant factors using ANOVA-PCA by selective reduction of residual variability.

Selective elimination of residual error can be used when applying Harrington's ANOVA-PCA in order to improve the capabilities of the method. ANOVA-PCA is sometimes unable to discriminate between levels of a factor when sources of high residual variability are present. In some cases this variability is not random, possesses some structure and is large enough to be responsible for the first principal components calculated by the PCA step in the ANOVA-PCA. This fact sometimes makes it impossible for the interesting variance to be in the first two PCA components. By using the proposed selective residuals elimination procedure, one may improve the ability of the method to detect significant factors as well as have an understanding of the different kinds of residual variance present in the data. Two datasets are used to show how the method is used in order to iteratively detect variance associated with the factors even when it is not initially visible. A permutation method is used to confirm that the observed significance of the factors was not accidental.

Two new extensions of principal component transform to compute a PLS2 model between two wide matrices: PCT-PLS2 and segmented PCT-PLS2.

The progress of analytical techniques has led to the possibility of acquiring a large number of data for each analysed sample. Moreover, the application of pre-treatment methods such as Contrast greatly increases the number of variables, yielding (very) wide data matrices. The computation of a PLS2 model between two such matrices may be slowed down, or made impossible, because of computer memory problems. The method presented in this article proposes an algorithm to solve this problem, and to enable the computation of a PLS2 model between two matrices containing a large number of variables. To do this, the PLS2 model is computed between the score matrices obtained by a PCA on each original matrix separately. After PLS2, a back-transformation to the original space is possible, and leads to results identical to those which would have been obtained in the original space. The method can be later extended, by segmenting the matrices, and computing the PC transform on each segment, before concatenating all the resulting score matrices and computing the PLS2 model on the obtained matrices.

Fruit juice authentication by 1H NMR spectroscopy in combination with different chemometrics tools.

To discriminate orange juice from grapefruit juice in a context of fraud prevention, (1)H NMR data were submitted to different treatments to extract informative variables which were then analysed using multivariate techniques. Averaging contiguous data points of the spectrum followed by logarithmic transformation improved the results of the data analysis. Moreover, supervised variable selection methods gave better rates of classification of the juices into the correct groups. Last, independent-component analysis gave better classification results than principal-component analysis. Hence, ICA may be an efficient chemometric tool to detect differences in the (1)H NMR spectra of similar samples, and so may be useful for authentication of foods.

Evolving window zone selection method followed by independent component analysis as useful chemometric tools to discriminate between grapefruit juice, orange juice and blends.

This study investigates the use of high resolution 1H NMR as a suitable alternative to the standard chromatographic method for the determination of adulteration of orange juice (Citrus sinensis) with grapefruit juice (Citrus paradisi) based on flavonoid glycoside content. Fifty-nine orange juices (OJ), 23 grapefruit juices (GJ) and 10 blends (OG), obtained from local retail outlets were used to assess the performance of the 1H NMR method. The work presented here introduces the Evolving Window Zone Selection (EWZS) function that holds promise for the automatic detection of spectral regions tailored to discriminate predefined groups. This technique was applied on the pre-processed 1H NMR spectra of the 92 juices. Independent Component Analysis (ICA) is a good alternative to Principal Component Analysis (PCA) for recovering linearly-mixed unobserved multidimensional independent signals and has been used in this study to build supervised models that classify the samples into three categories, OJ, GJ, OG. The regions containing the known flavonoid glycoside markers were selected as well as another zone containing the signals of sucrose, alpha-glucose and other components that were tentatively attributed. ICA was applied on three different groups of selected variables and showed good results for both discrimination and interpretation of the signals. Up to 97.8% of the juices were correctly attributed. This method gave better results than the commonly used PCA method. In addition, the time required to carry out the 1H NMR analysis was less than half the time of the standard chromatographic method.

Selecting the optimum number of partial least squares components for the calibration of attenuated total reflectance-mid-infrared spectra of undesigned kerosene samples.

Selecting the correct dimensionality is critical for obtaining partial least squares (PLS) regression models with good predictive ability. Although calibration and validation sets are best established using experimental designs, industrial laboratories cannot afford such an approach. Typically, samples are collected in an (formally) undesigned way, spread over time and their measurements are included in routine measurement processes. This makes it hard to evaluate PLS model dimensionality. In this paper, classical criteria (leave-one-out cross-validation and adjusted Wold's criterion) are compared to recently proposed alternatives (smoothed PLS-PoLiSh and a randomization test) to seek out the optimum dimensionality of PLS models. Kerosene (jet fuel) samples were measured by attenuated total reflectance-mid-IR spectrometry and their spectra where used to predict eight important properties determined using reference methods that are time-consuming and prone to analytical errors. The alternative methods were shown to give reliable dimensionality predictions when compared to external validation. By contrast, the simpler methods seemed to be largely affected by the largest changes in the modeling capabilities of the first components.

Study of the behaviour of amino acids in aqueous solution by time-domain NMR and high-resolution NMR.

The study of protein hydration by time-domain NMR is complicated by the great number of interactions involved, resulting from the presence of several amino acids and the possible modifications produced by the various structures. Moreover, a good comprehension of the molecular interactions of the simple amino acids in solution is essential to elucidate the mechanism of the biological functions of proteins. Measurements of transverse relaxation rates of the protons of water (R(2) = 1/T(2)) in aqueous solutions of amino acids such as L-glycine, L-asparagine, L-arginine and L-tryptophan were carried out in order to study the effects of chemical exchange and molecular diffusion on the amplitude of R(2). The values of R(2) measured by the Carr-Purcell-Meiboom-Gill (CPMG) sequence were studied while varying the solution pH and the parameters of the CPMG sequence. The dependence of R(2) on pH and tau (inter-pulse delay between the first and the second pulses of the CPMG sequence) is interpreted in terms of chemical exchange between the protons of water and those of the labile amino acid groups. This interpretation was confirmed by the analysis of the proton spectra acquired using a 300 MHz NMR spectrometer.

Lakes, wetlands, and streams as predictors of land use/cover distribution.

The importance of the surrounding landscape to aquatic ecosystems has been well established. Most research linking aquatic ecosystems to landscapes has focused on the one-way effect of land on water. However, to understand fully the complex interactions between aquatic and terrestrial ecosystems, aquatic ecosystems must be seen not only as receptors of human modification of the landscape, but also as potential drivers of these modifications. We hypothesized that the presence of aquatic ecosystems influences the spatial distribution of human land use/cover of the nearby landscape (

Variability of cork from Portuguese Quercus suber studied by solid-state (13)C-NMR and FTIR spectroscopies.

A new approach is presented for the study of the variability of Portuguese reproduction cork using solid-state (13)C-NMR spectroscopy and photoacoustic (PAS) FTIR (FTIR-PAS) spectroscopy combined with chemometrics. Cork samples were collected from 12 different geographical sites, and their (13)C-cross-polarization with magic angle spinning (CP/MAS) and FTIR spectra were registered. A large spectral variability among the cork samples was detected by principal component analysis and found to relate to the suberin and carbohydrate contents. This variability was independent of the sample geographical origin but significantly dependent on the cork quality, thus enabling the distinction of cork samples according to the latter property. The suberin content of the cork samples was predicted using multivariate regression models based on the (13)C-NMR and FTIR spectra of the samples as reported previously. Finally, the relationship between the variability of the (13)C-CP/MAS spectra with that of the FTIR-PAS spectra was studied by outer product analysis. This type of multivariate analysis enabled a clear correlation to be established between the peaks assigned to suberin and carbohydrate in the FTIR spectrum and those appearing in the (13)C-CP/MAS spectra.

Hydration properties and the role of water in taste modalities of sucrose, caffeine, and sucrose-caffeine mixtures.

Solution properties of sapid molecules are informative on their type of hydration (hydrophobic or hydrophilic) and on the extent of the hydration layer. Physicochemical properties (intrinsic viscosity and apparent specific volume) and nuclear magnetic resonance (NMR) relaxation rates R(1) and R(2) for pure sucrose, bitter molecule caffeine, and their mixture were found to be relevant in the interpretation of the effects of these solutes on water mobility. Likewise, surface tension, contact angles with a hydrophobic surface, and the adhesion forces to this type of surface of the aqueous solutions of sapid molecules were found to discriminate between their effects on water cohesion and also between their taste qualities. The interpretation of the two sets of independent experimental results, namely physicochemical and spectroscopic data, helps in the elucidation of the role of water in sweet and bitter taste chemoreception.

Breast cancer detection: knowledge, attitudes, and behaviors of women from Pennsylvania.

PURPOSE/OBJECTIVES: To assess relationships among breast cancer detection behaviors and selected variables in healthy women. DESIGN: Correlational study. SETTING/SAMPLE: A sample of 1,000 women was selected randomly from the 16,500 members of the General Federation of Women's Clubs of Pennsylvania. Respondents (N = 538; 54% response rate) were predominately white, well educated, lived in urban areas, and had an average age of 60 years. METHODS: Mailed packets with a professionally designed, scannable survey instrument that included questions related to detection behaviors, a risk index, health behaviors, attitudes, and knowledge. MAIN RESEARCH VARIABLES: Breast cancer detection behaviors: mammography, clinical breast examination (CBE), breast self-examination (BSE). Structural/demographic variables: age, education, residence, knowledge of breast cancer and detection methods, teaching history, encouragement, and risk index (family/medical history). Predisposing variables: susceptibility, benefits/barriers, confidence, social norms and influence, and general health motivation. FINDINGS: Women reported moderate/high adherence to recommendations for early detection of breast cancer. Mammography behavior was predicted by older age, being encouraged by a doctor or nurse, and greater risk. CBE predictors were greater knowledge and risk along with greater benefits, social norms, and health motivation. BSE behavior was predicted by having had BSE technique checked, greater knowledge, greater risk, decreased barriers to BSE, and higher health motivation. CONCLUSIONS: Common predictors of breast screening behaviors include risk (family/medical history), knowledge, and general health motivation. IMPLICATIONS FOR NURSING PRACTICE: Educational efforts can be designed specifically to influence variables related to compliance with early breast cancer detection behaviors.

Changes in well-being of women cancer survivors following a survivor weekend experience.

PURPOSE/OBJECTIVES: To determine the long-term effects on quality of life (QOL) of women cancer survivors following a retreat experience. DESIGN: One-group repeated measures. SETTING: Southern California. SAMPLE: Participants in two 1998 Healing Odyssey Retreats (N = 41; response rate 67%). Most women were married (50%), had breast cancer (93%), and had been diagnosed within two years of the retreat (69%). Participants' mean age was 48 years. METHODS: The rehabilitative retreats took place in a mountain retreat center and consisted of multiple experiences guided by experiential learning theory. Exercises aimed to help women learn new tools for dealing with the challenges of cancer, treatment, and recovery. The QOL-Breast Cancer survey was used to collect data preretreat, immediately postretreat, at six weeks postretreat, and at six to seven months postretreat. MAIN RESEARCH VARIABLES: QOL subscale scores (physical, psychological, social, and spiritual well-being) and overall QOL scores. FINDINGS: At preretreat, women scored lower on psychological and social well-being than on physical and spiritual well-being. Total QOL, physical, psychological, and spiritual well-being scores differed significantly over time, with a significant increase immediately following the retreat that was maintained at six weeks and six months. Social well-being at six months was significantly greater than at the other three points. CONCLUSIONS: The Healing Odyssey Retreats enhanced women cancer survivors' total QOL-specifically their well-being in four dimensions. IMPLICATIONS FOR NURSING PRACTICE: Women who seek programs dealing with living life more fully after cancer and connections with other survivors may benefit from rehabilitative efforts such as this retreat.

Quantitation of aliphatic suberin in Quercus suber L. cork by FTIR spectroscopy and solid-state (13)C-NMR spectroscopy.

This work determined that the percentage of suberin in cork may be found by solid-state (13)C cross polarization/magic angle spinning (CP/MAS) NMR spectroscopy and by FTIR with photoacoustic detection (FTIR-PAS) spectroscopy. A linear relationship is found between the suberin content measured through CP/MAS spectral areas and that measured gravimetrically. Furthermore, application of a partial least squares (PLS1) regression model to the NMR and gravimetric data sets clearly correlates the two sets, enabling suberin quantification with 90% precision. Suberin quantitation by FTIR-PAS spectroscopy is also achieved by a PLS1 regression model, giving 90% accurate estimates of the percentage of suberin in cork. Therefore, (13)C-CP/MAS NMR and FTIR-PAS proved to be useful and accurate noninvasive techniques to quantify suberin in cork, thus avoiding the traditional time consuming and destructive chemical methods.

Consequences of delay in surgical treatment of biliary disease.

BACKGROUND: Delay of laparoscopic cholecystectomy after the diagnosis of uncomplicated biliary disease is common at our institution. This study assessed the effect of delay of operation for symptomatic biliary disease. METHODS: A cohort of 251 patients was retrospectively reviewed at Parkland Memorial Hospital with follow-up available for 168 patients (67%) from January 1998 to July 1998. Data were analyzed using Student's t test and the chi-square test. RESULTS: Of the 88 patients with the initial diagnosis of biliary colic, 69 (78%) underwent elective laparoscopic cholecystectomy. Thirty-six patients made a total of 44 return visits the emergency department with a recurrent attack of biliary colic or a complication of gallstone disease. Mean operative time increased from 94 minutes for elective operations to 122 minutes for nonelective operations and hospital stay increased from 0.6 days to 6.1 days. Conversion to open operation increased from 6% in the elective group to 26% in the nonelective group. CONCLUSION: Delay of surgical therapy is associated with complications, increased operative times, higher conversion to open cholecystectomy, and prolonged hospitalization. We conclude that patients with symptomatic cholelithiasis should undergo early cholecystectomy.