José Rodrigues - Academia.edu (original) (raw)

Papers by José Rodrigues

Research paper thumbnail of Contrasting nitrogen fertilization treatments impact xylem gene expression and secondary cell wall lignification in Eucalyptus

BMC Plant Biology, 2014

Background: Nitrogen (N) is a main nutrient required for tree growth and biomass accumulation. In... more Background: Nitrogen (N) is a main nutrient required for tree growth and biomass accumulation. In this study, we analyzed the effects of contrasting nitrogen fertilization treatments on the phenotypes of fast growing Eucalyptus hybrids (E. urophylla x E. grandis) with a special focus on xylem secondary cell walls and global gene expression patterns. Results: Histological observations of the xylem secondary cell walls further confirmed by chemical analyses showed that lignin was reduced by luxuriant fertilization, whereas a consistent lignin deposition was observed in trees grown in N-limiting conditions. Also, the syringyl/guaiacyl (S/G) ratio was significantly lower in luxuriant nitrogen samples. Deep sequencing RNAseq analyses allowed us to identify a high number of differentially expressed genes (1,469) between contrasting N treatments. This number is dramatically higher than those obtained in similar studies performed in poplar but using microarrays. Remarkably, all the genes involved the general phenylpropanoid metabolism and lignin pathway were found to be down-regulated in response to high N availability. These findings further confirmed by RT-qPCR are in agreement with the reduced amount of lignin in xylem secondary cell walls of these plants. Conclusions: This work enabled us to identify, at the whole genome level, xylem genes differentially regulated by N availability, some of which are involved in the environmental control of xylogenesis. It further illustrates that N fertilization can be used to alter the quantity and quality of lignocellulosic biomass in Eucalyptus, offering exciting prospects for the pulp and paper industry and for the use of short coppices plantations to produce second generation biofuels.

Research paper thumbnail of A common near infrared—based partial least squares regression model for the prediction of wood density of Pinus pinaster and Larix × eurolepis

Wood Science and Technology, 2010

Abstract Wood density is defined as the ratio of mass to volume and therefore in principle it sho... more Abstract Wood density is defined as the ratio of mass to volume and therefore in principle it should be possible to calculate a unique partial least squares regression (PLS-R) model for several species. PLS-R models for wood density based on X-ray microdensity data were calculated for each species Pinus pinaster and Larix× eurolepis and for both species together. After cross-validation and test set validation the data sets were combined and final models were calculated. The common model gave a residual prediction deviation (RPD) ...

Research paper thumbnail of Eucalypt pulp yield QTL from Raiz as compared to the literature

BMC …, 2011

Background RAIZ is a Portuguese private non-profit research institute owned by the Pulp & Paper P... more Background RAIZ is a Portuguese private non-profit research institute owned by the Pulp & Paper Portucel Soporcel Group (http://www. raiz-iifp. pt webcite). RAIZ E. globulus genetic improvement program is managed in order to generate trees with increased economic ...

Research paper thumbnail of Improvement of Pinus pinaster Ait elite trees selection by combining near infrared spectroscopy and genetic tools

Holzforschung, 2000

An Error Occurred Setting Your User Cookie. This site uses cookies to improve performance. If you... more An Error Occurred Setting Your User Cookie. This site uses cookies to improve performance. If your browser does not accept cookies, you cannot view this site. Setting Your Browser to Accept Cookies. There are many reasons why a cookie could not be set correctly. ...

Research paper thumbnail of Influence of tree eccentric growth on syringyl/guaiacyl ratio in Eucalyptus globulus wood lignin assessed by analytical pyrolysis

Journal of Analytical and Applied Pyrolysis, 2001

Wood disks from 9-year-old Eucalyptus globulus trees that showed eccentric growth were analysed b... more Wood disks from 9-year-old Eucalyptus globulus trees that showed eccentric growth were analysed by analytical pyrolysis to determine lignin syringyl/guaiacyl (s/g) ratio, lignin content and polysaccharide composition (hexosans/hexosans+pentosans). Three cross-sectional fractions were analysed: the long radius, the short radius and the intermediate sections. Between-tree variation was observed for the s/g ratio from 2.0 to 2.8, the lignin content from 26.5 to 28.0% and the hesosans/hexosans+ pentosans ratio from 0.76 to 0.83. The reliability of the pyrolysis analysis assessed by the pooled standard deviation was very high for the three determinations (2-3% coefficients of variation). Eccentric tree growth in E. globulus has no impact in the s/g ratio and does not necessarily imply differences in lignin content or in polysaccharide composition. When differences occur, lower lignin and higher cellulose are found in the cross section part with the highest radial growth. Sampling for wood chemical analysis in eccentric cross sections should avoid the stem parts with high radial differences between opposite sides. Analytical pyrolysis can be used to prospect for the presence of tension wood.

Research paper thumbnail of NIR PLSR model selection for Kappa number prediction of maritime pine Kraft pulps

Wood Science and Technology, 2007

A total of 910 maritime pine (Pinus pinaster Aiton) wood discs, belonging to a genetic trial of 8... more A total of 910 maritime pine (Pinus pinaster Aiton) wood discs, belonging to a genetic trial of 80 families with 11-12 trees per family, were used in this study. A near infrared (NIR) partial least squares regression (PLSR) model for the prediction of Kappa number of Pinus pinaster Aiton pulps obtained from samples pulped under identical conditions was calculated. Very good correlations between NIR spectra of maritime pine pulps and Kappa numbers in the range from 58 to 100 were obtained. Besides the raw spectra, spectra pre-processed with ten methods were used for PLS analysis (cross validation with 57 samples), showing that even after test set validation (with 34 samples) no model decision could be made due to almost identical statistics. The final evaluation that proved the predictive power of the models by predicting pulps with unknown Kappa numbers allowed choosing a model Ó Springer-Verlag 2007 according to a minimal number of outliers found during this process. The minimum-maximum normalized spectra in the wave number range from 6,110 to 5,440 cm -1 used for the calculation gave the best model with a root mean square error of prediction of 2.3 units of Kappa number, a coefficient of determination of 95.9%, and one PLS component. The percentage of outliers during evaluation was 0.9%.

Research paper thumbnail of Calibration of NIR to assess lignin composition (H/G ratio) in maritime pine wood using analytical pyrolysis as the reference method

Research paper thumbnail of Estudio del contenido y la calidad de la lignina mediante Pirólisis analítica en madera de Pinus caribaea

Maderas. Ciencia y tecnología, 2007

En este trabajo se presentan los resultados alcanzados en la determinación del contenido de ligni... more En este trabajo se presentan los resultados alcanzados en la determinación del contenido de lignina así como de su calidad (relación H/G) en muestras de madera de Pinus caribaea var caribaea de tres localidades en la provincia de Pinar del Río, Cuba. El estudio se realizó en el Instituto de Investigación Científica Tropical de Lisboa, Portugal, en el marco del Proyecto GEMA. La técnica utilizada fue la Pirólisis analítica. Los resultados que se muestran representan el promedio de tres corridas experimentales y se obtuvieron valores cercanos al método Klason utilizado como referencia. Se encontró una correlación aceptable entre los contenidos del lignina-pirólisis y lignina Klason para esta especie, lo cual permite calcular el contenido de lignina Klason a través del contenido de ligninapirólisis. La pirólisis analítica es de gran utilidad en los programas de mejoramiento genético, en que es necesario el análisis de muchas muestras, ya que la introducción de parámetros como la composición química de la madera, induce al desarrollo de métodos expeditos de caracterización, reproducibles y de bajo costo, una vez que los métodos tradicionales son lentos, requieren mucha mano de obra y son de elevado costo.

Research paper thumbnail of Genetic parameters of wood properties in Picea abies

Hannrup, B. Cahalan, C. Chantre, G. Grabner, M. Karlsson, B. Le Bayon, I. Muller, U. Pereira, H. ... more Hannrup, B. Cahalan, C. Chantre, G. Grabner, M. Karlsson, B. Le Bayon, I. Muller, U. Pereira, H. Rodrigues, JC Rosner, S. Rozenberg, P. Wilhelmsson, L. Wimmer, R. ... There are no files associated with this item. ... Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Research paper thumbnail of Adsorption of acid orange 7 dye in aqueous solutions by spent brewery grains

Spent brewery grains (SBG), a by-product of the brewing process, were tested as an adsorbent of a... more Spent brewery grains (SBG), a by-product of the brewing process, were tested as an adsorbent of acid orange 7 dye (AO7), a monoazo acid dye currently used in paper and textile industries. The presence of AO7 in these effluents causes obvious environmental problems.

Research paper thumbnail of Impact of solar activity on the growth of pine trees: case study

In this work, we focus on the analysis of data for the ring width of two pine tree species: sampl... more In this work, we focus on the analysis of data for the ring width of two pine tree species: samples of six maritime pines (Pinus pinaster), grown in the north of Portugal, and one sample of Scots pine (Pinus sylvestris), grown in the south of Slovakia. A negative impact of solar activity (SA) was observed on the growth of these pine trees with particularly strong impact in the case of the maritime pines. The width of the annual rings was generally smaller in the years of maximum SA; furthermore, it was found that it is latewood width that is affected whereas earlywood width is not affected; as a corollary, the percentage of latewood also shows a significative negative correlation with SA.

Research paper thumbnail of Influência da actividade solar nos anéis de crescimento da Pinus Sylvestris L

Resumo:É sabido que as características da madeira produzidas pelas árvores estão sujeitas a um va... more Resumo:É sabido que as características da madeira produzidas pelas árvores estão sujeitas a um vasto conjunto de factores, como sejam a localização geográfica, condições do solo, do clima, genéticos, etc. Perante o crescente interesse da influência dos factores ambientais sobre o crescimento das árvores, particularmente sob a actual ameaça de ocorrência de alterações climáticas, no presente trabalho e recorrendo à microdensitometria da madeira por raios-x, foi analisado o efeito da actividade solar nas características dos anéis de crescimento de uma árvore de Pinus Sylvestris L. com 180 anos, localizada no Observatório Central de Hurbanovo (Eslováquia). Os resultados obtidos revelaram que a actividade solar poderá afectar o crescimento e a densidade da madeira sendo, responsável por cerca de 20% da variação total de algumas características da madeira. Verificou-se que o efeito da actividade solar é mais acentuado nas características da densidade e do crescimento da madeira formada durante o Verão/Outono (Lenho Final), do que na madeira formada durante a Primavera (Lenho Inicial). Verificou-se que nos anos de maior actividade solar as árvores formaram anéis com menor Densidade Máxima e Densidade do Lenho Final e, por isso, também menor Densidade Média e Índice de Heterogeneidade. Relativamente às características de crescimento, estes anéis apresentaram também uma redução da Largura do Lenho Final, Percentagem de Lenho Final e Largura do Anel.

Research paper thumbnail of Oriental LacquersHardening Process Characterization by FTIR Microspectroscopy and Py-GC/MS

Research paper thumbnail of Kappa Number Prediction of Acacia melanoxylon Unbleached Kraft Pulps using NIR-PLSR Models with a Narrow Interval of Variation

A total of 120 Acacia melanoxylon R. Br. (Australian blackwood) stem discs, belonging to 20 trees... more A total of 120 Acacia melanoxylon R. Br. (Australian blackwood) stem discs, belonging to 20 trees from four sites in Portugal, were used in this study. The samples were kraft pulped under standard identical conditions targeted to a Kappa number of 15. A Near Infrared (NIR) partial least squares regression (PLSR) model was developed for the Kappa number prediction using 75 pulp samples with a narrow Kappa number variation range of 10 to 17. Very good correlations between NIR spectra of A. melanoxylon pulps and Kappa numbers were obtained. Besides the raw spectra, also pre-processed spectra with ten methods were used for PLS analysis (cross validation with 48 samples), and a test set validation was made with 27 samples. The first derivative spectra in the wavenumber range from 6110 to 5440 cm -1 yielded the best model with a root mean square error of prediction of 0.4 units of Kappa number, a coefficient of determination of 92.1%, and two PLS components, with the ratios of performance to deviation (RPD) of 3.6 and zero outliers. The obtained NIR-PLSR model for Kappa number determination is sufficiently accurate to be used in screening programs and in quality control.

Research paper thumbnail of Analytical pyrolysis as a direct method to determine the lignin content in wood

In Part 1, a method for the quantification of the lignin content (Py-lignin) of Maritime pine and... more In Part 1, a method for the quantification of the lignin content (Py-lignin) of Maritime pine and spruce wood samples directly from the pyrograms was presented (A. Alves, M. Schwanninger, H. Pereira, J. Rodrigues, J. Anal. Appl. Pyrol. 76 (2006a) 209). The good correlation found between the Py-lignin and Klason lignin content gave a common model to both species.

Research paper thumbnail of Aspectos anatômicos e tecnológicos de painéis confeccionados com fibras de eucalipto e cana-de-açúcar

Research paper thumbnail of Determination of Eucalyptus globulus wood extractives content by near infrared-based partial least squares regression models: comparison between extraction procedures

Research paper thumbnail of Building up resources and knowledge to unravel transcriptomics dynamics underlying Eucalyptus globulus xylogenesis

BMC Proceedings, 2011

The economic importance of some Eucalyptus species, including interspecific hybrids, has been ext... more The economic importance of some Eucalyptus species, including interspecific hybrids, has been extended from the traditional interest of pulp and paper production to the emergent areas of bio-fuels and bio-materials. New genomic resources and high throughput technologies have provided the Eucalyptus research international community with the opportunities to identify genomic regions of interest in order to comprehensively dissect, catalogue and characterize genes involved in the determination of wood formation and quality. Similar strategies can be now applied to identify key regulator genes and better understand the cellular mechanisms by which they modulate the complex molecular events occurring in xylogenesis.

Research paper thumbnail of Deciphering cork formation in Quercus suber

Research paper thumbnail of Application of near infrared spectroscopy and multivariate data analysis for the evaluation of glue lines of untreated and copper azole treated laminated timber before and after ageing

Polymer Degradation and Stability, 2009

The necessity for inspection and assessment of glued laminated timber structures in service has r... more The necessity for inspection and assessment of glued laminated timber structures in service has raised interest in the evaluation of the glue lines. Glue line spectra were analysed and are discussed in detail with respect to spectral contributions from the adhesive, the hardener, the wood lamella below the adhesive, the curing temperature as well as ageing-related spectral changes. The combination

Research paper thumbnail of Contrasting nitrogen fertilization treatments impact xylem gene expression and secondary cell wall lignification in Eucalyptus

BMC Plant Biology, 2014

Background: Nitrogen (N) is a main nutrient required for tree growth and biomass accumulation. In... more Background: Nitrogen (N) is a main nutrient required for tree growth and biomass accumulation. In this study, we analyzed the effects of contrasting nitrogen fertilization treatments on the phenotypes of fast growing Eucalyptus hybrids (E. urophylla x E. grandis) with a special focus on xylem secondary cell walls and global gene expression patterns. Results: Histological observations of the xylem secondary cell walls further confirmed by chemical analyses showed that lignin was reduced by luxuriant fertilization, whereas a consistent lignin deposition was observed in trees grown in N-limiting conditions. Also, the syringyl/guaiacyl (S/G) ratio was significantly lower in luxuriant nitrogen samples. Deep sequencing RNAseq analyses allowed us to identify a high number of differentially expressed genes (1,469) between contrasting N treatments. This number is dramatically higher than those obtained in similar studies performed in poplar but using microarrays. Remarkably, all the genes involved the general phenylpropanoid metabolism and lignin pathway were found to be down-regulated in response to high N availability. These findings further confirmed by RT-qPCR are in agreement with the reduced amount of lignin in xylem secondary cell walls of these plants. Conclusions: This work enabled us to identify, at the whole genome level, xylem genes differentially regulated by N availability, some of which are involved in the environmental control of xylogenesis. It further illustrates that N fertilization can be used to alter the quantity and quality of lignocellulosic biomass in Eucalyptus, offering exciting prospects for the pulp and paper industry and for the use of short coppices plantations to produce second generation biofuels.

Research paper thumbnail of A common near infrared—based partial least squares regression model for the prediction of wood density of Pinus pinaster and Larix × eurolepis

Wood Science and Technology, 2010

Abstract Wood density is defined as the ratio of mass to volume and therefore in principle it sho... more Abstract Wood density is defined as the ratio of mass to volume and therefore in principle it should be possible to calculate a unique partial least squares regression (PLS-R) model for several species. PLS-R models for wood density based on X-ray microdensity data were calculated for each species Pinus pinaster and Larix× eurolepis and for both species together. After cross-validation and test set validation the data sets were combined and final models were calculated. The common model gave a residual prediction deviation (RPD) ...

Research paper thumbnail of Eucalypt pulp yield QTL from Raiz as compared to the literature

BMC …, 2011

Background RAIZ is a Portuguese private non-profit research institute owned by the Pulp & Paper P... more Background RAIZ is a Portuguese private non-profit research institute owned by the Pulp & Paper Portucel Soporcel Group (http://www. raiz-iifp. pt webcite). RAIZ E. globulus genetic improvement program is managed in order to generate trees with increased economic ...

Research paper thumbnail of Improvement of Pinus pinaster Ait elite trees selection by combining near infrared spectroscopy and genetic tools

Holzforschung, 2000

An Error Occurred Setting Your User Cookie. This site uses cookies to improve performance. If you... more An Error Occurred Setting Your User Cookie. This site uses cookies to improve performance. If your browser does not accept cookies, you cannot view this site. Setting Your Browser to Accept Cookies. There are many reasons why a cookie could not be set correctly. ...

Research paper thumbnail of Influence of tree eccentric growth on syringyl/guaiacyl ratio in Eucalyptus globulus wood lignin assessed by analytical pyrolysis

Journal of Analytical and Applied Pyrolysis, 2001

Wood disks from 9-year-old Eucalyptus globulus trees that showed eccentric growth were analysed b... more Wood disks from 9-year-old Eucalyptus globulus trees that showed eccentric growth were analysed by analytical pyrolysis to determine lignin syringyl/guaiacyl (s/g) ratio, lignin content and polysaccharide composition (hexosans/hexosans+pentosans). Three cross-sectional fractions were analysed: the long radius, the short radius and the intermediate sections. Between-tree variation was observed for the s/g ratio from 2.0 to 2.8, the lignin content from 26.5 to 28.0% and the hesosans/hexosans+ pentosans ratio from 0.76 to 0.83. The reliability of the pyrolysis analysis assessed by the pooled standard deviation was very high for the three determinations (2-3% coefficients of variation). Eccentric tree growth in E. globulus has no impact in the s/g ratio and does not necessarily imply differences in lignin content or in polysaccharide composition. When differences occur, lower lignin and higher cellulose are found in the cross section part with the highest radial growth. Sampling for wood chemical analysis in eccentric cross sections should avoid the stem parts with high radial differences between opposite sides. Analytical pyrolysis can be used to prospect for the presence of tension wood.

Research paper thumbnail of NIR PLSR model selection for Kappa number prediction of maritime pine Kraft pulps

Wood Science and Technology, 2007

A total of 910 maritime pine (Pinus pinaster Aiton) wood discs, belonging to a genetic trial of 8... more A total of 910 maritime pine (Pinus pinaster Aiton) wood discs, belonging to a genetic trial of 80 families with 11-12 trees per family, were used in this study. A near infrared (NIR) partial least squares regression (PLSR) model for the prediction of Kappa number of Pinus pinaster Aiton pulps obtained from samples pulped under identical conditions was calculated. Very good correlations between NIR spectra of maritime pine pulps and Kappa numbers in the range from 58 to 100 were obtained. Besides the raw spectra, spectra pre-processed with ten methods were used for PLS analysis (cross validation with 57 samples), showing that even after test set validation (with 34 samples) no model decision could be made due to almost identical statistics. The final evaluation that proved the predictive power of the models by predicting pulps with unknown Kappa numbers allowed choosing a model Ó Springer-Verlag 2007 according to a minimal number of outliers found during this process. The minimum-maximum normalized spectra in the wave number range from 6,110 to 5,440 cm -1 used for the calculation gave the best model with a root mean square error of prediction of 2.3 units of Kappa number, a coefficient of determination of 95.9%, and one PLS component. The percentage of outliers during evaluation was 0.9%.

Research paper thumbnail of Calibration of NIR to assess lignin composition (H/G ratio) in maritime pine wood using analytical pyrolysis as the reference method

Research paper thumbnail of Estudio del contenido y la calidad de la lignina mediante Pirólisis analítica en madera de Pinus caribaea

Maderas. Ciencia y tecnología, 2007

En este trabajo se presentan los resultados alcanzados en la determinación del contenido de ligni... more En este trabajo se presentan los resultados alcanzados en la determinación del contenido de lignina así como de su calidad (relación H/G) en muestras de madera de Pinus caribaea var caribaea de tres localidades en la provincia de Pinar del Río, Cuba. El estudio se realizó en el Instituto de Investigación Científica Tropical de Lisboa, Portugal, en el marco del Proyecto GEMA. La técnica utilizada fue la Pirólisis analítica. Los resultados que se muestran representan el promedio de tres corridas experimentales y se obtuvieron valores cercanos al método Klason utilizado como referencia. Se encontró una correlación aceptable entre los contenidos del lignina-pirólisis y lignina Klason para esta especie, lo cual permite calcular el contenido de lignina Klason a través del contenido de ligninapirólisis. La pirólisis analítica es de gran utilidad en los programas de mejoramiento genético, en que es necesario el análisis de muchas muestras, ya que la introducción de parámetros como la composición química de la madera, induce al desarrollo de métodos expeditos de caracterización, reproducibles y de bajo costo, una vez que los métodos tradicionales son lentos, requieren mucha mano de obra y son de elevado costo.

Research paper thumbnail of Genetic parameters of wood properties in Picea abies

Hannrup, B. Cahalan, C. Chantre, G. Grabner, M. Karlsson, B. Le Bayon, I. Muller, U. Pereira, H. ... more Hannrup, B. Cahalan, C. Chantre, G. Grabner, M. Karlsson, B. Le Bayon, I. Muller, U. Pereira, H. Rodrigues, JC Rosner, S. Rozenberg, P. Wilhelmsson, L. Wimmer, R. ... There are no files associated with this item. ... Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Research paper thumbnail of Adsorption of acid orange 7 dye in aqueous solutions by spent brewery grains

Spent brewery grains (SBG), a by-product of the brewing process, were tested as an adsorbent of a... more Spent brewery grains (SBG), a by-product of the brewing process, were tested as an adsorbent of acid orange 7 dye (AO7), a monoazo acid dye currently used in paper and textile industries. The presence of AO7 in these effluents causes obvious environmental problems.

Research paper thumbnail of Impact of solar activity on the growth of pine trees: case study

In this work, we focus on the analysis of data for the ring width of two pine tree species: sampl... more In this work, we focus on the analysis of data for the ring width of two pine tree species: samples of six maritime pines (Pinus pinaster), grown in the north of Portugal, and one sample of Scots pine (Pinus sylvestris), grown in the south of Slovakia. A negative impact of solar activity (SA) was observed on the growth of these pine trees with particularly strong impact in the case of the maritime pines. The width of the annual rings was generally smaller in the years of maximum SA; furthermore, it was found that it is latewood width that is affected whereas earlywood width is not affected; as a corollary, the percentage of latewood also shows a significative negative correlation with SA.

Research paper thumbnail of Influência da actividade solar nos anéis de crescimento da Pinus Sylvestris L

Resumo:É sabido que as características da madeira produzidas pelas árvores estão sujeitas a um va... more Resumo:É sabido que as características da madeira produzidas pelas árvores estão sujeitas a um vasto conjunto de factores, como sejam a localização geográfica, condições do solo, do clima, genéticos, etc. Perante o crescente interesse da influência dos factores ambientais sobre o crescimento das árvores, particularmente sob a actual ameaça de ocorrência de alterações climáticas, no presente trabalho e recorrendo à microdensitometria da madeira por raios-x, foi analisado o efeito da actividade solar nas características dos anéis de crescimento de uma árvore de Pinus Sylvestris L. com 180 anos, localizada no Observatório Central de Hurbanovo (Eslováquia). Os resultados obtidos revelaram que a actividade solar poderá afectar o crescimento e a densidade da madeira sendo, responsável por cerca de 20% da variação total de algumas características da madeira. Verificou-se que o efeito da actividade solar é mais acentuado nas características da densidade e do crescimento da madeira formada durante o Verão/Outono (Lenho Final), do que na madeira formada durante a Primavera (Lenho Inicial). Verificou-se que nos anos de maior actividade solar as árvores formaram anéis com menor Densidade Máxima e Densidade do Lenho Final e, por isso, também menor Densidade Média e Índice de Heterogeneidade. Relativamente às características de crescimento, estes anéis apresentaram também uma redução da Largura do Lenho Final, Percentagem de Lenho Final e Largura do Anel.

Research paper thumbnail of Oriental LacquersHardening Process Characterization by FTIR Microspectroscopy and Py-GC/MS

Research paper thumbnail of Kappa Number Prediction of Acacia melanoxylon Unbleached Kraft Pulps using NIR-PLSR Models with a Narrow Interval of Variation

A total of 120 Acacia melanoxylon R. Br. (Australian blackwood) stem discs, belonging to 20 trees... more A total of 120 Acacia melanoxylon R. Br. (Australian blackwood) stem discs, belonging to 20 trees from four sites in Portugal, were used in this study. The samples were kraft pulped under standard identical conditions targeted to a Kappa number of 15. A Near Infrared (NIR) partial least squares regression (PLSR) model was developed for the Kappa number prediction using 75 pulp samples with a narrow Kappa number variation range of 10 to 17. Very good correlations between NIR spectra of A. melanoxylon pulps and Kappa numbers were obtained. Besides the raw spectra, also pre-processed spectra with ten methods were used for PLS analysis (cross validation with 48 samples), and a test set validation was made with 27 samples. The first derivative spectra in the wavenumber range from 6110 to 5440 cm -1 yielded the best model with a root mean square error of prediction of 0.4 units of Kappa number, a coefficient of determination of 92.1%, and two PLS components, with the ratios of performance to deviation (RPD) of 3.6 and zero outliers. The obtained NIR-PLSR model for Kappa number determination is sufficiently accurate to be used in screening programs and in quality control.

Research paper thumbnail of Analytical pyrolysis as a direct method to determine the lignin content in wood

In Part 1, a method for the quantification of the lignin content (Py-lignin) of Maritime pine and... more In Part 1, a method for the quantification of the lignin content (Py-lignin) of Maritime pine and spruce wood samples directly from the pyrograms was presented (A. Alves, M. Schwanninger, H. Pereira, J. Rodrigues, J. Anal. Appl. Pyrol. 76 (2006a) 209). The good correlation found between the Py-lignin and Klason lignin content gave a common model to both species.

Research paper thumbnail of Aspectos anatômicos e tecnológicos de painéis confeccionados com fibras de eucalipto e cana-de-açúcar

Research paper thumbnail of Determination of Eucalyptus globulus wood extractives content by near infrared-based partial least squares regression models: comparison between extraction procedures

Research paper thumbnail of Building up resources and knowledge to unravel transcriptomics dynamics underlying Eucalyptus globulus xylogenesis

BMC Proceedings, 2011

The economic importance of some Eucalyptus species, including interspecific hybrids, has been ext... more The economic importance of some Eucalyptus species, including interspecific hybrids, has been extended from the traditional interest of pulp and paper production to the emergent areas of bio-fuels and bio-materials. New genomic resources and high throughput technologies have provided the Eucalyptus research international community with the opportunities to identify genomic regions of interest in order to comprehensively dissect, catalogue and characterize genes involved in the determination of wood formation and quality. Similar strategies can be now applied to identify key regulator genes and better understand the cellular mechanisms by which they modulate the complex molecular events occurring in xylogenesis.

Research paper thumbnail of Deciphering cork formation in Quercus suber

Research paper thumbnail of Application of near infrared spectroscopy and multivariate data analysis for the evaluation of glue lines of untreated and copper azole treated laminated timber before and after ageing

Polymer Degradation and Stability, 2009

The necessity for inspection and assessment of glued laminated timber structures in service has r... more The necessity for inspection and assessment of glued laminated timber structures in service has raised interest in the evaluation of the glue lines. Glue line spectra were analysed and are discussed in detail with respect to spectral contributions from the adhesive, the hardener, the wood lamella below the adhesive, the curing temperature as well as ageing-related spectral changes. The combination