- E-postolav.kvalheim@uib.no
- BesøksadresseAllégaten 41Realfagbygget5007 Bergen
- PostadressePostboks 78035020 Bergen
I am mainly working with i) instrumental characterization/profiling of complex multicomponent systems (body fluids and tissue) and development of data-analytical methods and algorithms for resolution, exploration, pattern recognition, discrimination and classification of such systems, and, ii) applications of such methods to solve multifaceted problems of medical and pharmaceutical origin. Typically, spectral or chromatographic fingerprints of whole or fractionated samples are used to select features characterizing and/or discriminating groups of samples or to predict properties such as e.g. bioactivity of natural products or disease states for patients. Feature selection provides a strategy to reveal so-called biomarkers, molecules carrying specific information about biological processes such as pathogenesis. This can be molecules displaying the disease pattern in a way that can be utilized for diagnostic or therapeutic purposes. Collaboration with medical research groups is established in obesity research, and, for neurological diseases (multiple sclerosis). Analytical instrumentation such as NMR, chromatography and mass spectroscopy combined with chemometrics represents key technologies for pattern recognition and biomarker discovery for early diagnosis, risk analysis, and, monitoring of disease development and therapeutic effects.
Master and PhD projects are provided within the areas of new algortihms and methods for profiling and data analysis of complex systems, and, application of such methods to solve medical and pharmaceutical problems.
Examples of recent master theses:
1. Analysis of Brain Lipids Using NMR and Multivariate Methods
2. Multivariate characterization and analysis of brain lipids
Vitenskapelig artikkel
- (2022). Physical activity intensity profiles associated with cardiometabolic risk in middle-aged to older men and women. Preventive Medicine. 9 sider.
- (2022). Interaction Metabolomics to Discover Synergists in Natural Product Mixtures. Journal of natural products. 655-671.
- (2022). Associations of lipoprotein particle profile and objectively measured physical activity and sedentary time in schoolchildren: a prospective cohort study. International Journal of Behavioral Nutrition and Physical Activity. 14 sider.
- (2022). An approach to assess and adjust for the influence of multicollinear covariates on metabolomics association patterns-applied to a study of the associations between a comprehensive lipoprotein profile and the homeostatic model assessment of insulin resistance. Metabolomics. 1-10.
- (2021). Variation in Phenolic Chemistry in Zostera marina Seagrass Along Environmental Gradients. Plants. 17 sider.
- (2021). GRANADA consensus on analytical approaches to assess associations with accelerometer-determined physical behaviours (physical activity, sedentary behaviour and sleep) in epidemiological studies. British Journal of Sports Medicine. 9 sider.
- (2019). Interpretation of multivariate association patterns between multicollinear physical activity accelerometry data and cardiometabolic health in children-a tutorial. Metabolites. 14 sider.
- (2018). The multivariate physical activity signature associated with metabolic health in children. International Journal of Behavioral Nutrition and Physical Activity.
- (2017). Aerobic fitness and metabolic health in children: A clinical validation of directly measured maximal oxygen consumption versus performance measures as markers of health. Preventive Medicine Reports. 74-76.
- (2016). Serum fatty acid and lipoprotein subclass concentrations and their associations in prepubertal healthy Norwegian children. Metabolomics.
- (2016). Predictive associations between serum fatty acids and lipoproteins in healthy non-obese Norwegians: implications for cardiovascular health. Metabolomics.
- (2016). Intensive lifestyle intervention provides rapid reduction of serum fatty acid levels in women with severe obesity without lowering omega-3 to unhealthy levels. Clinical Obesity. 259-267.
- (2016). Effects of physical activity on schoolchildren's academic performance: The Active Smarter Kids (ASK) cluster-randomized controlled trial. Preventive Medicine. 322-328.
- (2016). Biochemometrics for Natural Products Research: Comparison of Data Analysis Approaches and Application to Identification of Bioactive Compounds. Journal of natural products. 376-386.
- (2015). Changes in Serum Fatty Acid Levels During the First Year After Bariatric Surgery. Obesity Surgery.
- (2015). Active Smarter Kids (ASK): Rationale and design of a cluster-randomized controlled trial investigating the effects of daily physical activity on children's academic performance and risk factors for non-communicable diseases. BMC Public Health.
- (2014). Variable importance in latent variable regression models. Journal of Chemometrics. 615-622.
- (2013). Physical activity versus sedentary behavior: associations with lipoprotein particle subclass concentrations in healthy adults. PLOS ONE. 9 sider.
- (2013). Impact of physical activity and diet on lipoprotein particle concentrations in severely obese women participating in a 1-year lifestyle intervention. Clinical Obesity. 202-213.
- (2012). History, philosophy and mathematical basis of the latent variable approach - from a peculiarity in psychology to a general method for analysis of multivariate data. Journal of Chemometrics. 210-217.
- (2011). Resolving co-eluting chromatographic patterns by means of dissimilarity analysis in iterative target transformation factor analysis. Journal of Chromatography A. 7219-7225.
- (2011). Chromatographic profiling and multivariate analysis for screening and quantifying the contributions from individual components to the bioactive signature in natural products. Chemometrics and Intelligent Laboratory Systems. 98-105.
- (2010). The vector of calibration ratios: A simple transfer method for mass spectra. Journal of Chromatography A. 5986-5994.
- (2010). Interpretation of partial least squares regression models by means of target projection and selectivity ratio plots. Journal of Chemometrics. 9 sider.
- (2010). Detection and use of selective ions for providing initial estimates of the concentration vectors in iterative target transformation factor analysis. Journal of Chromatography A. 3128-3135.
- (2010). A multivariate approach to reveal biomarker signatures for disease classification: application to mass spectral profiles of cerebrospinal fluid from patients with multiple sclerosis. Journal of Proteome Research. 3608-3620.
- (2009). X-tended target projection (XTP) - comparison with orthogonal partial least squares (OPLS) and PLS post-processing by similarity transformation (PLS + ST). Journal of Chemometrics. 49-55.
- (2009). Recipe for Uncovering the Bioactive Components in Herbal Medicine. Analytical Chemistry. 7217-7225.
- (2009). Discriminating Variable Test and Selectivity Ratio Plot: Quantitative Tools for Interpretation and Variable (Biomarker) Selection in Complex Spectral or Chromatographic Profiles. Analytical Chemistry. 2581-2590.
- (2009). Biomarker discovery in mass spectral profiles by means of selectivity ratio plot. Chemometrics and Intelligent Laboratory Systems. 35-48.
- (2008). Uncorrelated linear discriminant analysis (ULDA): A powerful tool for exploration of metabolomics data. Chemometrics and Intelligent Laboratory Systems. 70-79.
- (2008). Modeling based on subspace orthogonal projections for QSAR and QSPR research. Journal of Chemometrics. 23-36.
- (2007). Quantifying disturbances in benthic communities - comparison of the community disturbance index (CDI) to other multivariate methods. Ecological Indicators. 254-276.
- (2007). Pretreatment of mass spectral profiles: Application to proteomic data. Analytical Chemistry. 7014-7026.
- (2007). Pre-analytical influence on the low molecular weight cerebrospinal fluid proteome. PROTEOMICS - Clinical Applications. 699-711.
- (2007). A comparison of different pre-treatment procedures for reducing heteroscedasticity and other irrelevant features in data prior to modelling of benthic count profiles. Journal of Chemometrics. 386-396.
- (2004). Toxicological evaluation of complex mixtures: fingerprinting and multivariate analysis. Environmental Toxicology and Pharmacology. 127-133.
- (2004). Quantification of pollution levels by multiway modelling. Journal of Chemometrics. 173-182.
- (2004). Quantification of pollution levels by multiway modelling. Journal of Chemometrics. 173-182.
- (2004). Assigning environmental variables to observed biological changes. Analytical and Bioanalytical Chemistry. 453-466.
- (2004). A method for validation of reference sets in SIMCA modelling. Chemometrics and Intelligent Laboratory Systems. 101-109.
- (2004). A method for validation of reference sets in SIMCA modelling. Chemometrics and Intelligent Laboratory Systems. 101-109.
- (2003). Screening of biomakers in rat urine using LC/MC electrospray ionization-MS and two-way data analysis. Analytical Chemistry. 4784-4792.
- (2002). Toxicological evaluation of complex mixtures by pattern recognition: Correlating chemical fingerprints to mutagenicity. Environmental Health Perspectives. 985-988.
- (2002). Study of the Self-Association of Alcohols by Near-Infrared Spectroscopy and Multivariate 2D Techniques. Journal of Physical Chemistry A. 8543-8553.
- (2002). Feasibility study of NIR for surveillance of a pharmaceutical process, including a study of different preprocessing techniques. Journal of Chemometrics. 529-541.
- (2001). Resolution of GC-MS Data of Complex PAC Mixtures and Regression Modeling of Mutagenicity by PLS. Environmental Science and Technology. 2314-2318.
- (2001). Interactions in chromatographic separation of resins from deasphaltened crude oils studied by means of infrared spectroscopy and principal component analysis. Fuel. 717-730.
- (2001). Automated curve resolution applied to data from multi-detection instruments. Analytica Chimica Acta. 313-328.
- (2000). Quantitative determination of asphaltenes and resins in solution by means of near-infrared spectroscopy. Correlations to emulsion stability. Journal of Colloid and Interface Science. 494-504.
- (2000). Multivarite screening analysis of water-in-oil emulsions in high external electric fields as studied by means of dielectric time domain spectroscopy - III emulsions containing asphaltenes and resins. Journal of Colloid and Interface Science. 262-271.
- (2000). Morphological score and its application to chemical rank determination. Chemometrics and Intelligent Laboratory Systems. 37-47.
- (2000). Determination of chemical rank of two-way data from subspace comparisons. Chemometrics and Intelligent Laboratory Systems. 49-59.
- (2000). Crude oil model emulsion characterised by means of near infrared spectroscopy and multivariate techniques. Journal of Dispersion Science and Technology. 245-262.
- (1998). Friedel-Crafts Acylation on Porous Divinyl Benzene Polymer Particles: A Reaction Kinetic Process Studied by Mid-and Near-Infrared spectroscopy. Applied Spectroscopy. 1230-1239.
- (1997). Complexation between benzoic acid and fatty amines. An adsorption and chemometric study. Colloids and Surfaces. 135-144.
- (1997). Associative bahaviour of benzyl alcohol in carbon tetrachloride solutions. Journal of Physical Chemistry A. 6960-6969.
- (1997). Associative Behavior of Benzyl Alcohol in Carbon Tetrachloride Solutions. Journal of Physical Chemistry. 6960-6969.
- (1996). Self-Association of Medium-Chain Alcohols in n-Decane Solutions. Applied Spectroscopy. 1264-1272.
- (1996). Resolution of infrared profiles from variable temperature experiments on mixtures and conformers in rapid equilibrum by compensating for thermal and solvent effects. Vibrational Spectroscopy. 163-176.
- (1996). Proton nuclear magnetic resonance spectroscopy of serum from patients with colorectal neoplasia. European Journal of Surgical Oncology. 78-83.
- (1996). Proton nuclear magnetic resonance spectroscopy of serum from patients with colorectal neoplasia. European Journal of Surgical Oncology. 78-83.
- (1996). Proton nuclear magnetic resonance spectroscopy of serum from patients with colorectal neoplasia. European Journal of Surgical Oncology. 78-83.
- (1996). Proton nuclear magnetic resonance spectroscopy of serum from patients with colorectal neoplasia. European Journal of Surgical Oncology. 78-83.
- (1996). Projective modelling by SIMCA - a new dynamic strategy for cost-efficient environmental monitoring around offshore installations. Aquatic Sciences. 120-138.
- (1996). Methods for multivariate analysis. Chemometrics and Intelligent Laboratory Systems. 1-10.
- (1996). Influence and correction of peak shift and band broadening observed by rank analysis on vibrational bands from variable-temperature measurement. Vibrational Spectroscopy. 105-123.
- (1996). A multivariate analysis of w/o emulsions in high external electric fields, as studied by means of dielectric time domain spectroscopy. Part II. Model emulsions stabilised by interfacially active fractions from crude oils. Journal of Colloid and Interface Science. 396-405.
- (1996). A multivariate analysis of w/o emulsions in high external electric fields, as studied by means of dielectric time domain spectroscopy. Journal of Colloid and Interface Science. 117-125.
- (1995). Particle size effect on diffuse reflectance spectra: Modification of Kubelka-Munk equation. Vibrational Spectroscopy. 19-27.
- (1995). Maturity trends in asphaltenes from pyrolysed source rocks and natural coals-Multivariate modelling of diffuse reflectance Fourier transform infrared spectra. Organic Geochemistry. 139-158.
- (1995). Determination of the equilibrium constant and resolution of the HOD spectrum by alternating least squares. Applied Spectroscopy. 561-568.
- (1994). Structure of liquid water determined from infrared temperature profiling and evolutionary curve resolution. Journal of the American Chemical Society. 8311-8316.
- (1994). Speed improvement of multivariate algorithms by the method of postponed basis matrix multiplication method. Part II. Three-mode principal component analysis. Chemometrics and Intelligent Laboratory Systems. 43-54.
- (1994). Speed improvement of multivariate algorithms by the method of postponed basis matrix multiplication method. Part 1. Principal component analysis. Chemometrics and Intelligent Laboratory Systems. 31-42.
- (1994). Spectra of water in the near- and mid-infrared region. Vibrational Spectroscopy. 243-254.
- (1994). Resolution of infrared spectra and kinetic analysis of mutarotation of D-Glucose in water by sequential rank analysis. Vibrational Spectroscopy. 139-148.
- (1994). Resolution of embedded chromatographic peaks by sequential rank analysis of the firs-order differentiated elution profile in the domiain. Chemometrics and Intelligent Laboratory Systems. 229-240.
- (1994). Rank determination of spectroscopi data by means of cross validation - The effect of replicated measurements on the degrees of fredom. Chemometrics and Intelligent Laboratory Systems. 115-125.
- (1994). Preprocessing of analytical profiles in the presence of homoscedastic or heteroscedastic noise. Analytical Chemistry. 43-51.
- (1994). Prediction of the Shannon Wiener index from trace element profiles in sediments around the Statfjord platforms. Chemosphere. 1441-1465.
- (1994). Nonlinear curve fitting of bilinear data by ortogonal projections for rank analysis. Applications to GC-IR and temperature IR studies. Vibrational Spectroscopy. 125-137.
- (1994). Non-linear curvefitting of bilinear data using orthogonal projections for rank analysis. Applications to gas chromatography/ infrared spectrometry and variable temperature infrared studies. Vibrational Spectroscopy. 125-137.
- (1994). Non-linear curvefitting of bilinear data using orthogonal projections for rank analysis. Applications to gas chromatography/ infrared spectrometry and variable temperature infrared studies. Vibrational Spectroscopy. 125-137.
- (1994). Multi-array resolution parameter for multidetection chromatography. Performance of alternating regression, iterative target transformation factor analysis and heuristic evolving latent projections. Chemometrics and Intelligent Laboratory Systems. 61-75.
- (1994). Investigation of the allomerization reaction of chlorophyll a: use of diode array HPLC, mass spectrometry and chemometric factor analysis for the detection of early products. Photochemistry and Photobiology. 99-110.
- (1994). Diagnosis and resolution of multiwavelength chromatograms by rank map, orthogonal projections and sequential rank analysis. Analytica Chimica Acta. 5-15.
- (1994). Determination of kinetic parameters for the dehydration of calcium oxalate monohydrate by diffuse reflectance infrared FT-IR spectroscopy. Applied Spectroscopy. 561-568.
- (1994). Compression of three-mode data arrays by B-splines prior to three-mode principal component analysis (PCA). Chemometrics and Intelligent Laboratory Systems. 29-38.
- (1994). Compression of an order data arrays by B-splines. Part 2. Application to second- order FT-IR data. Journal of Chemometrics. 127-145.
- (1994). Bulk compositional variations of coal asphaltenes studied by latent variable analysis of infrared microspectroscopic data. Chemometrics and Intelligent Laboratory Systems. 197-204.
- (1994). Assessment of peak origin and purity by orthogonal design and Heuristic evolving latent projections. Journal of Chromatography A. 113-122.
- (1993). White, grey and black - A classification of methods for quantitative analysis of multicomponent analytical systems. Chemometrics and Intelligent Laboratory Systems. 235-250.
- (1993). Use of chemometrics factor analysis for chromatographic integration: Application to diode-array high-performance liquid chroma tography of mixtures of chlorophyll a degradation products. The Analyst. 779-790.
- (1993). Unique resolution of hidden peaks in multidetection chromatography by first-order differentiation and orthogonal projectio ns. Analytica Chimica Acta. 425-440.
- (1993). Resolution parameter for multidetection chromatography. Analytical Chemistry. 2270-2275.
- (1993). Resolution of strongly overlapping two-way multicomponent data by means of Heuristic Evolving Latent Projections. Journal of Chemometrics. 15-43.
- (1993). Interpretation of chemical structural changes by target-projection analysis of infrared profiles. Vibrational Spectroscopy. 1-14.
- (1993). Heuristic evolving latent projections: Resolving hyphenated chromatographic profiles by component stripping. Chemometrics and Intelligent Laboratory Systems. 115-125.
- (1993). Eigenstructure tracking analysis for demonstration of heteroscedastic noise in instrumental profiles - application to transm ittance and aborbance IR. Chemometrics and Intelligent Laboratory Systems. 65-73.
- (1993). Effect of particle size on diffuse reflectance Fourier-transform infrared spectra of polystyrene spheres. Vibrational Spectroscopy. 233-244.
- (1993). Determination of detection limit and local chemical rank by designing a nonparametric test from the zero-component regions. Journal of Chemometrics. 277-289.
- (1993). Deconvolution in one-dimensional chromomatography by heuristic evolving latent projections of whole profiles retention time shifted b y Simplex optimization of cross correlation between target peaks. Analytica Chimica Acta. 101-114.
- (1993). Compression of n-order data arrays by B-splines. Part 1. Theory. KJ. Chemometrics. 61-73.
- (1993). A two-way procedure for background correction of chromatographic/spectroscopic data by means of congruence analysis and least-squares fit of the zero-component regions, comparison with double-centering. Chemometrics and Intelligent Laboratory Systems. 265-279.
- (1993). A gas cell for on-line transmission Fourier-transform infrared spectrometry. Vibrational Spectroscopy. 365-371.
- (1992). White, grey and black - A classification of methods for quantitative and qualitative analysis of multicomponent analytical systems. Chemometrics and Intelligent Laboratory Systems.
- (1992). The latent variable. Chemometrics and Intelligent Laboratory Systems. 1-3.
- (1992). Resolution of strongly overlapping two-way multicomponent data by means of Heuristic Evolving Latent Projections. Journal of Chemometrics.
- (1992). On-line pyrolysis of asphaltenes studied by Diffuse reflectance Fourier transform infrared spectroscopy. Fuel. 125-127.
- (1992). Laboratory Profile. Journal of Chemometrics. 113-116.
- (1992). Investigation of the allomerization reaction of chlorophylla: use of diode array HPLC, mass spectrometry and chemometrics factor analysis for the detection of early products. Photobiol.
- (1992). Investigation of the allomerization reaction of chlorophylla: use of diode array HPLC, mass spectrometry and chemometrics factor analysis for the detection of early products. Photochem.
- (1992). Heuristic Evolving Latent Projection - resolving two-way multicomponent data. Part 2. Detection and resolution of minor component. Analytical Chemistry. 946-953.
- (1992). Heuristic Evolving Latent Projection - resolving two-way multicomponent data. Part 1. Selectivity, latent-projective graph, datascope, local rank analysis and unique resolution. Analytical Chemistry. 936-946.
- (1992). Evolving factor analysis in the presence of heteroscedastic noise. Analytica Chimica Acta. 29-36.
- (1992). Estimation of prediction error for samples within the calibration range. Journal of Chemometrics. 177-188.
- (1992). Eigenstructure tracking analysis for demonstration of heteroscedastic noise in instrumental profiles - application to transmittance and oborbance IR. Chemometrics and Intelligent Laboratory Systems.
- (1992). Effect of particle size on diffuse reflectance infrared spectra of polysterene spheres. Vibrational Spectroscopy.
- (1992). Deconvolution in one-dimensional chromotography by heuristic evolving latent projections of whole profiles retention time shifted by Simplex optimization of cross correlation between target peaks. Analytica Chimica Acta.
- (1992). Constrained background bilinearization. Chemometrics and Intelligent Laboratory Systems. 175-184.
- (1992). Compression of n-order data arrays by B-plines. Part. theory. Journal of Chemometrics.
- (1992). Applications of diffuse reflectance Fourier-transform infrared spectroscopy in petroleum geochemistry. Scan Time.
- (1992). Applications of diffuse reflectance Fourier-transform infrared spectroscopy in petroleum geochemistry. Scan Time, Spectra-Tech.
- (1992). Applications of diffuse reflectance Fourier transform infrared spectroscopy in petroleum geochemistry. Spectra-Tech.
- (1992). Analysis of nontransparent polymers-mixture design, 2nd derivative attenuated total internal reflectance FT-IR and multivariate calibration. Applied Spectroscopy. 1002-1008.
- (1992). Analysis of non transparent polymers: Mixture design, 2nd derivate attenuated total internal reflectance FT-IR and multivariate calibration. Applied Spectroscopy. 1002-1008.
- (1992). A two-way procedure for background correction of chromatographic/ spectroscopic data by means of congruence analysis and least-squares fit of the zerocomponent regions, comparison with double-centering. Chemometrics and Intelligent Laboratory Systems.
- (1992). A comparison of the Heuristic envolving latent projection and evolving factor analysis methods for peak purity control in HPLCDAD. Analytica Chimica Acta. 63-71.
- (1991). On-Line pyrolysis of asphaltenes studied by Diffuse reflectance Fourier-transform infrared spectroscopy. Fuel. 125-127.
- (1991). Maturity of Kerogen and asphaltenes determined by Partial-Least -Squares (PLS) calibration and target projection of diffuse reflectance Fourier-transformed infrared spectra. Organic Geochemistry. 63-74.
- (1991). Diffuse reflectance Fourier-transformed infrared spectroscopy in petroleum exploration: A multivariate approach to maturity determination. Journal of Geochemical Exploration. 213-226.
- (1990). Detection of malignant tumors by multivariate analysis of proton magnetic resonance spectra of serum. European Journal of Cancer. 615-618.
- (1989). Structural features of resins, asphaltenes and kerogen studied by diffuse reflectance Fourier-transform infrared spectroscopy. Fuel. 429-435.
- (1989). Quantitative determination of thermal maturity in sedimentary organic matter by diffuse reflectance infrared spectroscopy of asphaltenes. Organic Geochemistry. 77-81.
- (1987). Multivariate calibration of diffuse reflectance Fourier-transform infrared spectra of coals as an alternative to rank determination by vitrinite reflectance. Chemometrics and Intelligent Laboratory Systems. 199-207.
- (1987). Maturity determination of organic matter in coals using the methyl phenanthrene distribution. Geochimica et Cosmochimica Acta. 1883-1888.
- (1987). Interpretation of multivariate data: Relationship between phenanthrenes in crude oils. Chemometrics and Intelligent Laboratory Systems. 149-153.
Vitenskapelig foredrag
- (2021). Revealing the information (bioactivity) in multicollinear profiles from natural product extracts.
- (2021). Characterization of crude oil and crude oil emulsions by NIR spectroscopy and multivariate analysis.
- (2021). A novel approach to handle confounders in multicollinear data - applied to study the relation of a measure of insulin resistance (the HOMA score) to lipoprotein subclass patterns in serum from prepubertal children.
- (2019). What is the best measure(s) of variable importance for interpretation and variable selection in multivariate regression models?
- (2019). Using chromatography and chemometrics for detecting bioactive components in very complex extracts of natural products.
- (2019). Optimal partial least squares models and predictions of properties using Monte Carlo resampling strategies.
- (2019). Optimal Partial Least Squares models and predictions of properties using Monte Carlo resampling strategies.
- (2018). Development and maintenance of process models - automating the selection and updating of models.
- (2018). Bruk av kjemometri til persontilpasset forebygging av livsstilssykdommer.
- (2017). Variable selection in process modeling.
- (2017). Selecting the “right” variables in latent variable regression (LVR) modelling in the presence of multicolinearity and orthogonal variation - optimal interpretation and prediction at the same time .
- (2017). Revealing the bioactive signature in multicomponent profiles.
- (2017). Monte Carlo Cross validation for component selection and determination of prediction error in latent-variable regression.
- (2017). Determination of optimum number of components in partial least squares regression.
- (2016). Which factors impact the lipid metabolism and how?
- (2016). Analysis of metabolomics data – examples from the study of the lipid metabolism.
- (2015). Predictive and orthogonal variation in latent variable regression and implications for the concept of model quality and model reduction.
- (2015). Chemometric-directed bioexploration of natural products.
- (2014). Variable importance and variable selection in spectral profiles from process analysers.
- (2014). Predictive and orthogonal variation in latent variable regression – model quality and model reduction .
- (2014). Optimal strategies and tools for interpretation and variable selection in spectral profiles from process analysers .
- (2014). Optimal strategies and tools for interpretation and variable selection in spectral profiles from process analysers.
- (2014). Model performance, interpretation, prediction performance and SOLV-DPM for process control.
- (2013). Relationship between physical activity and lipoprotein subclass changes in severely obese women.
- (2007). Target projection and proper data pre-treatment for the analysis of proteomic profiles.
- (2007). Preteatment of Mass Spectral Profiles: Application to proteomic data.
- (2007). Analysis of Proteomic Profiles: Pretreatment and Biomarker Discovery for early diagnosis of diseases.
- (2007). Analysis of Proteomic Profiles - Biomarker Discovery and Early Diagnosis.
- (2007). Analysis of Proteomic Profiles.
- (2003). Resolution of GC-MS and LC-MS profiles of very complex biomedical samples.
- (2003). Medical application of GC- and LC- MS and MS resolver.
- (2003). Introduction to design, Design of Experiments.
- (2003). Introduction of NOx-handling (pre & post, existing context, R&D, where are we today?) Handling of NOx in exhaust gases.
- (2001). Identification of and solution to the problem of lurking variables in industrial processes.
- (1997). The associative behaviour of benzyl alcohol in carbon tetrachloride solutions.
- (1997). PVA and related methods applied to improvement of industrial processes and product quality.
- (1997). Multivariate information extraction as a strategic and communication tool in the industrial enterprise.
- (1997). Kjemometri og kvalitet processes and product quality.
- (1997). Environmental monitoring and forecasting by means of multivariate methods.
- (1997). En innføring i multikomponentanalyse.
- (1997). Detection and resolution of overlapping peaks in multidetection chromatography.
- (1997). Chemometrics - advanced methods.
- (1997). 2-D multicomponent analysis by means of Extricator.
- (1993). Temperature dependency of the infrared spectra of water studied by Fourier-transform infrared spectroscopy.
- (1993). Particle size problem in diffuse reflectance spectrometry.
- (1993). Particle size problem in diffuse reflectance Fourier-transform infrared spectrometry. Plenary lecture.
- (1992). Multivariate analysis of infrared spectroscopic data: Application to the chemical transformation of sedimentary organic matter.
- (1992). Determination of activation energy for the thermal decomposition of kerogen by on-line pyrolysis infrared spectroscopy.
- (1992). Applications of chemometrics in infrared microspectroscopy.
Sammendrag/abstract
- (2018). The multivariate physical activity signature associated with metabolic health in children. Journal of Physical Activity and Health. 248-249.
- (2018). Lipoprotein subclasses and their associations with physical activity and sedentary time in Norwegian schoolchildren: The Active Smarter Kids study. Journal of Physical Activity and Health. 109-110.
- (2018). Associations for volumes and patterns of physical activity with metabolic health in children: a multivariate pattern analysis approach. Preventive Medicine.
- (2017). Strong association between cardiorespiratory fitness and serum lipoprotein subclass pattern in prepubertal healthy children. Medicine & Science in Sports & Exercise. 640-640.
- (2016). New strategies to identify synergists from Hydrastis canadensis (goldenseal). Planta Medica. 1 sider.
- (2016). Biochemometric analysis reveals complimentary bacterial inhibitory functionalities of the medicinal lichen Usnea barbata. Planta Medica. 1 sider.
- (2014). Effect of two types of bariatric surgery on the fatty acid profile in serum. The Complexity of Obesity Proceedings.
- (2014). A multivariate approach to reveal biomarker signatures in instrumental profiles of body fluids. The Complexity of Obesity Proceedings.
- (2011). Health Related Quality of Life in in-patients undergoing lifestyle treatment for morbid obesity. Obesity Reviews. 87-87.
- (2008). PAT - Optimal prediction of properties by means of tailormade modelling of spectroscopic/chromatographic profiles. European Journal of Pharmaceutical Sciences. S16-S16.
- (2008). Early diagnosis and biomarker discovery from mass spectral profiles: application to multiple sclerosis. Multiple Sclerosis. S285-S285.
- (2008). Biomarker discovery from mass spectral profiles: A combined proteomics and multivariate analysis. European Journal of Pharmaceutical Sciences. S27-S27.
Vitenskapelig oversiktsartikkel/review
- (2011). Multivariate data analysis in pharmaceutics: A tutorial review. International Journal of Pharmaceutics. 280-290.
Se fullstendig oversikt over publikasjoner i CRIStin.
Arneberg R., Rajalahti T., Flikka K., Berven F.S., Kroksveen A.C., Berle M., Myhr K.-M., Vedeler C., Ulvik R.J., Kvalheim O.M. (2007) Pretreatment of mass spectral profiles: Applications to proteomic data, Anal. Chem., 79, 7014-7026.
Kvalheim O.M., Rajalahti T., Arneberg R. (2009) X-tended Target Projection (XTP) – comparison with ortogonal partial least squares (OPLS) and PLS post-processing by similarity transformation (PLS+ST), J. Chemometrics, 23, 49-55.
Rajalahti T., Arneberg R., Berven F.S., Myhr K.-M., Ulvik R.J., Kvalheim O.M. (2009) Biomarker discovery in mass spectral profiles by means of selectivity ratio plot, Chemometrics & Intell. Lab. Syst., 95, 35-48.
Rajalahti T., Arneberg R, Kroksveen A.C., Berle M., Myhr K.-M., Kvalheim O.M. (2009) Discriminating variables test and selectivity ratio plot – Quantitative tools for interpretation and variable (biomarker) selection in complex spectral or chromatographic profiles, Analytical Chemistry, 81, 2581-90.
Chau F.-T., Chan H.-Y., Cheung C.-Y., Xu C.-J., Liang Y., Kvalheim O.M. (2009) Recipe for Uncovering the Bioactive Components in Herbal Medicine, Analytical Chemistry, 81, 7217-7225.
Rajalahti T., Kroksveen A.C., Arneberg R., Berven F.S., Vedeler C., Myhr K.-M., Kvalheim O.M. (2010) A multivariate approach to reveal biomarker signatures for disease classification: Application to mass spectral profiles of cerebrospinal fluid from patients with multiple sclerosis, J. Proteome Res., 9, 3608-3620.
Kvalheim O.M. (2010) Interpretation of partial least squares regression models by means of target projection and selectivity ratio plots, J. Chemometrics, 24, 496-504.
Kvalheim O.M., Chan H.-Y., Lau T.-Y., Benzie I.F.F, Szeto Y.-T., Tzang A.H.-C., Chau F.-T. (2011) Chromatographic Profiling and Multivariate analysis for revealing and quantifying the contributions from individual components to the Bioactive Signature in Natural Products, Chemom. & Intell. Lab. Syst., in press.
Rajalahti T., Kvalheim O.M. (2011), Multivariate data analysis in pharmaceutics: a tutorial review, Intern. J. Pharmaceutics, in press.