mayra Gonzalez - Academia.edu (original) (raw)
Papers by mayra Gonzalez
Summary. The biosynthesis of poly ([3-hydroxybutyrate) (PHB) by Bacillus circulans was carried ou... more Summary. The biosynthesis of poly ([3-hydroxybutyrate) (PHB) by Bacillus circulans was carried out through cultivation in nutrient broth in a single step. l~v of polymer fractions soluble in chloroform were close to 2 x 105. IR, 1H and 13C NMR spectra of the isolated PHB were in agreement with the assumed structure of this poly-l~-hydroxyester. NMR spectroscopy pointed out a high percentage of isotactic polymer, while differential scanning calorimetry showed that the PHB was crystalline.
IEE Proceedings - Nanobiotechnology, 2005
In this preliminary work, an enteric polymer has been used for encapsulating bovine serum albumin... more In this preliminary work, an enteric polymer has been used for encapsulating bovine serum albumine (BSA) as a model protein drug. Poly (lactide-co-glycolide) has been commonly used for oral administration purposes as a polymer matrix, but in this case an enteric polymer was used effectively to protect the protein in a gastric environment. A modified water/oil/water technique was used to decrease the particle diameter, and transmission electron microscopy experiments showed that the average diameter of the nanoparticles obtained was below 100 nm. The spherical nature of the particles and their diameters strongly depend on the control of the process parameters. The encapsulation efficiency was 77% for sample B4, and protein release profiles for both samples B3 and B4 indicate that these systems possess controlled-release characteristics. Finally, as a result of electrophoresis (SDS-PAGE), the BSA was not chemically affected under encapsulation conditions.
Environmental Engineering and Management Journal, 2015
The possibility to use release controlled fertilizers in the agriculture of the tropical countrie... more The possibility to use release controlled fertilizers in the agriculture of the tropical countries is more important than in the agriculture of the countries of the cold regions. In this context, the purpose of this work is the characterization of an encapsulated commercial Fertilizer of Controlled Release named FERLENT ® , which was covered with a polymeric material, obtained in situ, under controlled conditions, which allowed to corroborate the fairly well adjustment of the synthesis parameters for a succesful release of nutrients. It was characterized by Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA), Nuclear Magnetic Resonance (NMR) and infrared spectroscopy (FTIR). The agronomic benefits of fertilizer were shown during the in vivo cultivation of tomatos using the method of transplantation from stakes. The fertilizer exhibited an ecological effect, acting as an alternative nutrition source for tomatoes which achieved higher yields compared with traditional fertilization.
Journal of Sol-Gel Science and Technology, 2012
ABSTRACT The present work describes for the first time a new, simple and environmentally friend p... more ABSTRACT The present work describes for the first time a new, simple and environmentally friend procedure for preparing polyaniline/silica hybrid materials by combining the sol–gel method and in situ polymerization of aniline. The hybrid materials were characterized by X-ray diffraction, scanning electron micrography, Fourier transform infrared spectroscopy, 29Si CPMAS solid state nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The hybrids displayed lower electrical conductivity, but higher crystallinity degree than pure PAni. Also electromagnetic interference shielding effectiveness (EMI SE) in the frequency range from 8 to 12 GHz of the hybrid materials containing up to 55 % of silica was similar to that found for pure polyaniline but with higher absorbed power, mainly in lower frequency range. This work demonstrates for the first time that it is possible to obtain PAni/silica-based EMI shielding hybrid materials with similar efficiency as pure polyaniline but with higher thermal stability. Graphical Abstract
Revista …, 2007
RESUMEN La llamada tecnología de liberación lenta y controlada ha adquirido gran importancia tant... more RESUMEN La llamada tecnología de liberación lenta y controlada ha adquirido gran importancia tanto en el campo de la agricultura como en el de la medicina, siendo su principal objetivo la liberación lenta o gradual de un material activo desde una matriz ...
Biomacromolecules, 2011
The biosynthesis and characterization of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) p... more The biosynthesis and characterization of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) produced by Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. The biosynthesis of mcl-PHA in this newly isolated microorganism follows a growth-associated trend. Mcl-PHA accumulation ranging from 49.7 to 68.9% on cell dry weight (CDW) basis were observed when fatty acids ranging from octanoic acid (C 8:0) to oleic acid (C 18:1) were used as sole carbon and energy source. Molecular weight of the polymer was found to be ranging from 55.7 to 77.7 kDa. Depending on the type of fatty acid used, the 1 H NMR and GCMSMS analyses of the chiral polymer showed a composition of even and odd carbon atom chain with monomer length of C4 to C14 with C8 and C10 as the principal monomers. No unsaturated monomer was detected. Thermo-chemical analyses showed the accumulated PHA to be semi-crystalline polymer with good thermal stability, having a thermal degradation temperature (T d) of 264.6 to 318.8 (60.2) o C, melting temperature (T m) of 43. (60.2) o C, glass transition temperature (T g) of 21.0 (60.2) o C and apparent melting enthalpy of fusion (DH f) of 100.9 (60.1) J g 21 .
Cell, 2020
Summary Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables a... more Summary Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNA-seq) of metastatic lung cancer was performed using 49 clinical biopsies obtained from 30 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNA-seq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell-state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap-junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by scRNA-seq were biomarkers of clinical outcomes in independent cohorts. This study highlights how therapy-induced adaptation of the multi-cellular ecosystem of metastatic cancer shapes clinical outcomes.
Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptabil... more Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNAseq) of metastatic lung cancer was performed using 44 tumor biopsies obtained longitudinally from 27 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNAseq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by...
Macromolecular …, 2001
This paper reports the effect of water on the kinetics and mechanism of the heterogeneous polymer... more This paper reports the effect of water on the kinetics and mechanism of the heterogeneous polymerisation of 2-ethenylfuran initiated by trifluoroacetic acid in methylene dichloride solution. The structure of the resin, kinetics and mechanism of reactions depend ...
Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C 17 H 18 NF 3 O)] durin... more Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C 17 H 18 NF 3 O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N 2 adsorption, and x-ray diffraction to detect the interaction between the drug and the matrix. The complex nature of FTIR signals for the matrix and the drug did not allow observation of the interactions; however, using the density functional theory formalism, two stable complexes are suggested to be formed on the drug-matrix system. Both complexes are formed through H bond interactions involving the amine group in fluoxetine and the hydroxylated sites in titanium xerogel. They were found to be energetically stable and independent of the titanium model core cluster used in the calculations.
Journal of Materials Research, 2011
Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the ... more Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N2 adsorption, and x-ray diffraction to detect the ...
Journal of Materials Research, 2011
Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the ... more Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N2 adsorption, and x-ray diffraction to detect the ...
Summary. The biosynthesis of poly ([3-hydroxybutyrate) (PHB) by Bacillus circulans was carried ou... more Summary. The biosynthesis of poly ([3-hydroxybutyrate) (PHB) by Bacillus circulans was carried out through cultivation in nutrient broth in a single step. l~v of polymer fractions soluble in chloroform were close to 2 x 105. IR, 1H and 13C NMR spectra of the isolated PHB were in agreement with the assumed structure of this poly-l~-hydroxyester. NMR spectroscopy pointed out a high percentage of isotactic polymer, while differential scanning calorimetry showed that the PHB was crystalline.
IEE Proceedings - Nanobiotechnology, 2005
In this preliminary work, an enteric polymer has been used for encapsulating bovine serum albumin... more In this preliminary work, an enteric polymer has been used for encapsulating bovine serum albumine (BSA) as a model protein drug. Poly (lactide-co-glycolide) has been commonly used for oral administration purposes as a polymer matrix, but in this case an enteric polymer was used effectively to protect the protein in a gastric environment. A modified water/oil/water technique was used to decrease the particle diameter, and transmission electron microscopy experiments showed that the average diameter of the nanoparticles obtained was below 100 nm. The spherical nature of the particles and their diameters strongly depend on the control of the process parameters. The encapsulation efficiency was 77% for sample B4, and protein release profiles for both samples B3 and B4 indicate that these systems possess controlled-release characteristics. Finally, as a result of electrophoresis (SDS-PAGE), the BSA was not chemically affected under encapsulation conditions.
Environmental Engineering and Management Journal, 2015
The possibility to use release controlled fertilizers in the agriculture of the tropical countrie... more The possibility to use release controlled fertilizers in the agriculture of the tropical countries is more important than in the agriculture of the countries of the cold regions. In this context, the purpose of this work is the characterization of an encapsulated commercial Fertilizer of Controlled Release named FERLENT ® , which was covered with a polymeric material, obtained in situ, under controlled conditions, which allowed to corroborate the fairly well adjustment of the synthesis parameters for a succesful release of nutrients. It was characterized by Scanning Electron Microscopy (SEM), Thermogravimetric analysis (TGA), Nuclear Magnetic Resonance (NMR) and infrared spectroscopy (FTIR). The agronomic benefits of fertilizer were shown during the in vivo cultivation of tomatos using the method of transplantation from stakes. The fertilizer exhibited an ecological effect, acting as an alternative nutrition source for tomatoes which achieved higher yields compared with traditional fertilization.
Journal of Sol-Gel Science and Technology, 2012
ABSTRACT The present work describes for the first time a new, simple and environmentally friend p... more ABSTRACT The present work describes for the first time a new, simple and environmentally friend procedure for preparing polyaniline/silica hybrid materials by combining the sol–gel method and in situ polymerization of aniline. The hybrid materials were characterized by X-ray diffraction, scanning electron micrography, Fourier transform infrared spectroscopy, 29Si CPMAS solid state nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The hybrids displayed lower electrical conductivity, but higher crystallinity degree than pure PAni. Also electromagnetic interference shielding effectiveness (EMI SE) in the frequency range from 8 to 12 GHz of the hybrid materials containing up to 55 % of silica was similar to that found for pure polyaniline but with higher absorbed power, mainly in lower frequency range. This work demonstrates for the first time that it is possible to obtain PAni/silica-based EMI shielding hybrid materials with similar efficiency as pure polyaniline but with higher thermal stability. Graphical Abstract
Revista …, 2007
RESUMEN La llamada tecnología de liberación lenta y controlada ha adquirido gran importancia tant... more RESUMEN La llamada tecnología de liberación lenta y controlada ha adquirido gran importancia tanto en el campo de la agricultura como en el de la medicina, siendo su principal objetivo la liberación lenta o gradual de un material activo desde una matriz ...
Biomacromolecules, 2011
The biosynthesis and characterization of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) p... more The biosynthesis and characterization of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) produced by Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. The biosynthesis of mcl-PHA in this newly isolated microorganism follows a growth-associated trend. Mcl-PHA accumulation ranging from 49.7 to 68.9% on cell dry weight (CDW) basis were observed when fatty acids ranging from octanoic acid (C 8:0) to oleic acid (C 18:1) were used as sole carbon and energy source. Molecular weight of the polymer was found to be ranging from 55.7 to 77.7 kDa. Depending on the type of fatty acid used, the 1 H NMR and GCMSMS analyses of the chiral polymer showed a composition of even and odd carbon atom chain with monomer length of C4 to C14 with C8 and C10 as the principal monomers. No unsaturated monomer was detected. Thermo-chemical analyses showed the accumulated PHA to be semi-crystalline polymer with good thermal stability, having a thermal degradation temperature (T d) of 264.6 to 318.8 (60.2) o C, melting temperature (T m) of 43. (60.2) o C, glass transition temperature (T g) of 21.0 (60.2) o C and apparent melting enthalpy of fusion (DH f) of 100.9 (60.1) J g 21 .
Cell, 2020
Summary Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables a... more Summary Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNA-seq) of metastatic lung cancer was performed using 49 clinical biopsies obtained from 30 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNA-seq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell-state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap-junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by scRNA-seq were biomarkers of clinical outcomes in independent cohorts. This study highlights how therapy-induced adaptation of the multi-cellular ecosystem of metastatic cancer shapes clinical outcomes.
Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptabil... more Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNAseq) of metastatic lung cancer was performed using 44 tumor biopsies obtained longitudinally from 27 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNAseq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by...
Macromolecular …, 2001
This paper reports the effect of water on the kinetics and mechanism of the heterogeneous polymer... more This paper reports the effect of water on the kinetics and mechanism of the heterogeneous polymerisation of 2-ethenylfuran initiated by trifluoroacetic acid in methylene dichloride solution. The structure of the resin, kinetics and mechanism of reactions depend ...
Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C 17 H 18 NF 3 O)] durin... more Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C 17 H 18 NF 3 O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N 2 adsorption, and x-ray diffraction to detect the interaction between the drug and the matrix. The complex nature of FTIR signals for the matrix and the drug did not allow observation of the interactions; however, using the density functional theory formalism, two stable complexes are suggested to be formed on the drug-matrix system. Both complexes are formed through H bond interactions involving the amine group in fluoxetine and the hydroxylated sites in titanium xerogel. They were found to be energetically stable and independent of the titanium model core cluster used in the calculations.
Journal of Materials Research, 2011
Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the ... more Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N2 adsorption, and x-ray diffraction to detect the ...
Journal of Materials Research, 2011
Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the ... more Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N2 adsorption, and x-ray diffraction to detect the ...