15 results on '"Ribeiro HL"'
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2. Films from cashew byproducts: cashew gum and bacterial cellulose from cashew apple juice.
- Author
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Silva SMF, Ribeiro HL, Mattos ALA, Borges MF, Rosa MF, and de Azeredo HMC
- Abstract
Abstract: Cashew is a major crop in several tropical countries. Its cultivation is mostly aimed to the production of cashew nuts, whereas its byproducts (including cashew tree gum and cashew apples) are underutilized. In this study, cashew tree gum (CG) has been combined to nanofibrillated bacterial cellulose (NFBC) produced from cashew apple juice, at different ratios (from CG-only to NFBC-only), to produce edible films. While the CG-only dispersion (at 1 wt%) behaved as a quasi-Newtonian fluid, the addition of NFBC provided a shear-thinning behavior, making the dispersions easier to process, especially to cast. Moreover, the films containing increasing NFBC contents exhibited better physico-mechanical performance. When compared to the CG-only film, the films containing at least 25% NFBC presented remarkably higher strength and modulus (even similar to some conventional petroleum-derived polymers), lower water vapor permeability (WVP), and lower water solubility, although at the expense of lower elongation and higher opacity values. The combined use of both polysaccharides was demonstrated to be useful to overcome the limitations of both CG-only films (very low viscosity, poor tensile properties and very high WVP) and NFBC-only films (very high viscosity, making the dispersions difficult to mix and spread). Moreover, the use of different NFBC/CG ratios allow properties to be tuned to meet specific demands for different food packaging or coating purposes., (© Association of Food Scientists & Technologists (India) 2020.)
- Published
- 2021
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3. Complex coacervates of cashew gum and gelatin as carriers of green coffee oil: The effect of microcapsule application on the rheological and sensorial quality of a fruit juice.
- Author
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Oliveira WQ, Wurlitzer NJ, Araújo AWO, Comunian TA, Bastos MDSR, Oliveira AL, Magalhães HCR, Ribeiro HL, Figueiredo RW, and Sousa PHM
- Subjects
- Chromatography, Gas, Consumer Behavior, Diterpenes analysis, Food Handling, Food Technology, Fruit and Vegetable Juices analysis, Humans, Oxidation-Reduction, Rheology, Smell, Tamarindus chemistry, Taste, Anacardium chemistry, Capsules chemistry, Coffee chemistry, Gelatin chemistry, Plant Oils chemistry
- Abstract
In this work, cashew gum (CG) and gelatin (GE) complexation was explored to encapsulate green coffee oil (GCO), rich in cafestol and kahweol, for use as ingredient in fruit juice. The microcapsules were loaded with 25, 50 and 75% (w/w) GCO and characterized by scanning electron microscopy, encapsulation efficiency and accelerated oxidation by Rancimat. Gas chromatography coupled to the mass detector was used to cafestol quantification in simulated gastrointestinal digestion and during fruit juice storage. Particles with 25% GCO (14.56 ± 6.36 μm) presented good encapsulation efficiency (85.57 ± 1.41%), reduced the GCO oxidation by six-fold and were resisted in the pasteurization conditions. The beverage added of capsules showed good sensory quality when compared to the control formulation. For the first time, the incorporation of GCO capsules into fruit juice has been reported, promoting a diterpene-rich drink with good rheological and sensory properties., Competing Interests: Declaration of Competing Interest The authors declared that there is no conflict of interest., (Copyright © 2020. Published by Elsevier Ltd.)
- Published
- 2020
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4. Optimization of the collagen extraction from Nile tilapia skin (Oreochromis niloticus) and its hydrogel with hyaluronic acid.
- Author
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Menezes MDLLR, Ribeiro HL, Abreu FOMDS, Feitosa JPA, and Filho MSMS
- Subjects
- Animals, Cichlids, Collagen chemistry, Collagen isolation & purification, Particle Size, Surface Properties, Hyaluronic Acid chemistry, Hydrogels chemistry, Skin chemistry
- Abstract
Nile tilapia skin, an abundant waste from fish processing, can be used for collagen extraction, which has a high aggregated value for biomedical applications. Collagen extraction was conducted under different reaction conditions (time, temperature, and concentration of acetic acid) in order to optimize the yield without compromising the integrity of the collagen. Temperature and time were responsible for increased yield. The extraction at 4 and 20 °C produced the acid-solubilized collagen (ASC) with the intact triple helix and was analysed by Fourier-transform infrared spectroscopy (FT-IR) and circular dichroism (CD). The optimized ASC (which used 0.35 mol/L of acetic acid at 20 °C) was consumed to obtain for the first-time fish-based hydrogels with hyaluronic acid (HA) crosslinked with 1-ethyl-3-(3-dimethylaminopropryl carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The hydrogel was characterized by FT-IR, rheology, swelling, and scanning electron microscopy (SEM), confirming that cross-linking was accomplished. It possesses a robust organized network, swells 255 % in PBS and bears interconnected pores with a diameter in the range of 10-100 μm. Until now, col-HA hydrogels crosslinked with EDC/NHS have not been reported in literature with collagen from Nile Tilapia skin. Fish collagen can be a better option than those from land-based animals (cow and pig)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
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5. Effects of a physical activity and nutritional intervention in overweight and obese children through an educational and recreational camp.
- Author
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Rauber SB, Castro HO, Marinho A, Vicente JB, Ribeiro HL, Monteiro LZ, Praça IR, Simoes HG, and Campbell CSG
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- Camping, Child, Child Behavior, Female, Health Behavior, Humans, Leisure Activities, Male, Overweight, Program Evaluation, Recreation, Diet, Exercise, Feeding Behavior, Health Education, Health Promotion methods, Pediatric Obesity therapy, Sedentary Behavior
- Abstract
Background:: Educational camps have hosted millions of children around the world. However, few studies have described their benefits on weight control and health promotion for overweight and obese children., Aim:: To investigate the impact of a health educational program for children composed of 5 days of camp and a 12-week follow up on the physical activity level, sedentary behaviour, anthropometric data and food intake in overweight and obese children., Methods:: 12 children attended the Health Educational Program for Children divided into two phases. Phase 1 consisted of pre-assessments and Phase 2 corresponded to 12 weeks of follow up. Physical activity level, sedentary behaviour and food intake were assessed throughout the questionnaire., Results:: After the follow up, 25% of the children became active (>1500 and <3000 Metabolic Equivalent of Tasks per week). In contrast, the number of sedentary children (<600 Metabolic Equivalent of Tasks per week) decreased by 15% and insufficiently active (600-1500 Metabolic Equivalent of Tasks per week) increased by 15%. The physical activity level of leisure time increased significantly throughout weekdays (26.0%) and weekends (14.1%) after the follow up compared to before the camp. Sedentary behaviour showed a significant reduction of 177.14 and 41.43 minutes on weekdays and weekends, respectively. Before the camp, the consumption of sugar and sweets was out of control (100% inadequate), and after the intervention, 58.4% started to consume these foods in a balanced way., Conclusions:: The Health Educational Program for Children (5-day camp and the 12 weeks of follow up) contributed to an increase in the physical activity level and a reduction in the sedentary behaviour and anthropometric measures in overweight and obese children.
- Published
- 2018
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6. Stabilizing effect of montmorillonite on acerola juice anthocyanins.
- Author
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Ribeiro HL, Oliveira AV, Brito ES, Ribeiro PRV, Souza Filho MSM, and Azeredo HMC
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- Color, Mass Spectrometry, Rhamnose analogs & derivatives, Rhamnose chemistry, Anthocyanins chemistry, Bentonite chemistry, Food Additives chemistry, Fruit and Vegetable Juices analysis, Malpighiaceae chemistry
- Abstract
This study was conducted to evaluate color and anthocyanin stability of clarified acerola juice (CAJ) as affected by montmorillonite (Mnt) at different concentrations (0-6 wt%, dry basis). While non-complexed CAJ suffered noticeable color degradation with time and pH variations, the presence of Mnt (especially at 4-6 wt%) not only changed the initial color of CAJ but also made it more stable with time and pH changes. CAJ/Mnt mixtures were ultracentrifuged in order to separate them into supernatants and anthocyanin-complexed Mnt precipitates. The supernatants presented decreasing anthocyanin contents with increasing Mnt concentrations, indicating pigment retention by the precipitates. X-ray diffraction of precipitates showed that Mnt interlayer spacing was increased by increasing anthocyanin/Mnt ratios, corroborating anthocyanin intercalation. FTIR revealed a band at 1530 cm
-1 ascribed to formation of anthocyanin-Mnt complexes. Moreover, chromatograms indicated the selective adsorption of two compounds by Mnt, which were identified by LC-MS as cyanidin-3-O-rhamnoside and pelargonidin-3-O-rhamnoside., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2018
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7. Prognostic importance of Aurora Kinases and mitotic spindle genes transcript levels in Myelodysplastic syndrome.
- Author
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Borges DP, Dos Santos AWA, Paier CRK, Ribeiro HL Júnior, Costa MB, Farias IR, de Oliveira RTG, França IGDF, Cavalcante GM, Magalhães SMM, and Pinheiro RF
- Subjects
- Adult, Aged, Aged, 80 and over, Aurora Kinase A genetics, Aurora Kinase A metabolism, Aurora Kinase B genetics, Aurora Kinase B metabolism, Cdc20 Proteins genetics, Cdc20 Proteins metabolism, Cell Cycle Proteins genetics, Cell Cycle Proteins metabolism, Female, Humans, Kaplan-Meier Estimate, Mad2 Proteins genetics, Mad2 Proteins metabolism, Male, Microtubule-Associated Proteins genetics, Microtubule-Associated Proteins metabolism, Middle Aged, Myelodysplastic Syndromes mortality, Nuclear Proteins genetics, Nuclear Proteins metabolism, Prognosis, Spindle Apparatus genetics, Spindle Apparatus metabolism, Transcriptome, Young Adult, rho GTP-Binding Proteins genetics, rho GTP-Binding Proteins metabolism, Myelodysplastic Syndromes genetics, Myelodysplastic Syndromes pathology
- Abstract
Myelodysplastic syndrome (MDS) are a heterogeneous group of clonal disease characterized by insufficiency of bone marrow, increase of apoptosis and increased risk of acute leukemia progression. Proteins related to the mitotic spindle (AURKA, AURKB, TPX2), to the mitotic checkpoint (MAD2, CDC20) and the regulation of the cell cycle (p21) are directly related to chromosomal stability and tumor development. This study aimed to evaluate the mRNA expression levels of these genes in 101 MDS patients using a real-time PCR methodology. We identified that CDC20 expression are increased in patients with dysmegakaryopoiesis (p=0.024), thrombocytopenia (p=0.000) and high-risk patients (p=0.014, 0.018) MAD2 expression are decreased in patients with 2 or 3 cytopenias (p=0.000) and neutrophil below 800/mm
3 . TPX2 is also overexpressed in patients presenting dysmegakaryopoiesis (p=0.009). A decrease in AURKA and AURKB expression were observed in patients with altered karyotype (p=0.000), who presented dysplasia in 3 lineages (p=0.000; 0.017) and hemoglobin inferior to 8g/dL (p=0.024). The expression of AURKA, AURKB and MAD2 (p=0.000; 0.001; 0.025) were decreased in patients with hypoplastic MDS, associated with high frequency of chromosomal alterations and high mortality rate. This study reaffirms the importance of aurora kinases and mitotic spindle genes to the pathogenesis and clinical evolution of MDS., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2018
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8. Expression of DNA repair genes is important molecular findings in CD34 + stem cells of myelodysplastic syndrome.
- Author
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Ribeiro HL Jr, Maia ARS, de Oliveira RTG, Dos Santos AWA, Costa MB, Farias IR, Borges DP, Magalhães SMM, and Pinheiro RF
- Subjects
- DNA Repair, Hematopoietic Stem Cells, Humans, Stem Cells, Antigens, CD34, Myelodysplastic Syndromes
- Published
- 2018
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9. DNA repair gene expressions are related to bone marrow cellularity in myelodysplastic syndrome.
- Author
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Ribeiro HL Jr, Maia ARS, de Oliveira RTG, Costa MB, Farias IR, de Paula Borges D, de Sousa JC, Magalhães SMM, and Pinheiro RF
- Subjects
- Adult, Aged, Aged, 80 and over, Ataxia Telangiectasia Mutated Proteins genetics, BRCA1 Protein genetics, BRCA2 Protein genetics, Biopsy, Bone Marrow Examination, DNA Breaks, Double-Stranded, DNA Breaks, Single-Stranded, DNA Ligase ATP genetics, DNA-Binding Proteins genetics, Female, Gene Expression Regulation, Enzymologic, Genetic Markers, Humans, Kaplan-Meier Estimate, Male, Middle Aged, Myelodysplastic Syndromes mortality, Predictive Value of Tests, Real-Time Polymerase Chain Reaction, Transcription Factors genetics, Xeroderma Pigmentosum Group A Protein genetics, Young Adult, Bone Marrow Cells pathology, DNA Repair, DNA Repair Enzymes genetics, Myelodysplastic Syndromes genetics, Myelodysplastic Syndromes pathology
- Abstract
Objective: To evaluate the expression of genes related to nuclear excision ( ERCC8 , XPA and XPC ), homologous recombination and non-homologous end-joining ( ATM , BRCA1 , BRCA2 and LIG4 ) repair mechanisms, using quantitative PCR methodologies, and it relation with bone marrow cellularity in myelodysplastic syndrome (MDS)., Methods and Results: A total of 51 adult de novo patients with MDS (3 refractory anaemia (RA), 11 refractory anaemia with ringed sideroblasts (RARS), 28 refractory cytopenia with multilineage dysplasia (RCMD), 3 refractory anaemia with excess blasts type I (RAEB-I), 5 refractory anaemia with excess blasts type II (RAEB-II), and 1 chronic myelomonocytic leukaemia (CMML) were evaluated. For karyotype, 16.2% patients were defined as very low prognosis, 59.5% low risk, 8.1% intermediate risk, 5.4% high risk and 10.8% very high risk. For bone marrow cellularity, 17.6%, 17.6% and 64.7% presented as hypocellular, normocellular and hypercellular, respectively. Patients with hypocellular MDS had significantly decreased expression of ATM (p=0.000) , BRCA1 (p=0.014), BRCA2 (p=0.003) , LIG4 (p=0.004) and ERCC8 (p=0.000) than those with normocellular/hypercellular bone marrow, whereas XPA (p=0.049) and XPC (p=0.000) genes were increased. In patients with hypoplastic MDS, a low expression of ATM (p=0.0268), LIG4 (p=0.0199) and ERCC8 (p=0.0493) was significantly associated with the presence of chromosomal abnormalities. We detected positive correlations between BRCA1 and BRCA2 (r=0.416; p=0.007), ATM and LIG4 (r=0.472; p=0.001), LIG4 and BRCA1 (r=0.333; p=0.026), LIG4 and BRCA2 (r=0.334; p=0.025), ATM and XPA (r=0.377; p=0.008), ATM and XPC (r=0.287; p=0.046), LIG4 and XPC (r=0.371; p=0.007) and XPA and XPC genes (r=0.895; p=0.0000). We also found among all patients evaluated that correlation with LIG4 occurred most often., Conclusions: These correlations demonstrate the important intrinsic relations between single and double DNA strand breaks genes in MDS, emphasising that these genes are related to MDS pathogenesis., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)
- Published
- 2017
- Full Text
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10. Influence of functional polymorphisms in DNA repair genes of myelodysplastic syndrome.
- Author
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Ribeiro HL Junior, Soares Maia AR, Costa MB, Farias IR, de Paula Borges D, de Oliveira RT, de Sousa JC, Magalhães SM, and Pinheiro RF
- Subjects
- Adult, Ataxia Telangiectasia Mutated Proteins genetics, Bone Marrow metabolism, DNA Damage, DNA Ligase ATP genetics, Female, Genomic Instability genetics, Hematopoietic Stem Cells metabolism, Humans, Ku Autoantigen genetics, Male, Middle Aged, RNA, Messenger analysis, DNA Repair genetics, Leukemia, Myeloid, Acute genetics, Myelodysplastic Syndromes genetics, Polymorphism, Genetic
- Abstract
Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic stem cell (HSC) malignances characterized by peripheral cytopenias and predisposition to acute myeloid leukemia transformation. Several studies show that the MDS pathogenesis is a complex and heterogeneous process that involves multiple steps through a sequence of genetic lesions in the DNA which lead to functional changes in the cell and the emergence and subsequent evolution of pre-malignant clone. Double strand breaks (DSB) lesions are the most severe type of DNA damage in HSCs, which, if not properly repaired, might contribute to the development of chromosomal abnormalities, which in turn may lead to leukemia development. We assessed the mRNA expression levels of ATM, BRCA1, BRCA2, RAD51, XRCC5, XRCC6 and LIG4 genes in bone marrow samples of 47 MDS patients in order to evaluate the association with functional polymorphisms rs228593, rs4793191, rs9567623, rs1801320, rs3835, rs2267437 and rs1805388, respectively, and try to detect clinical associations. We found that the rs228593, rs2267437 and rs1805388 functional polymorphisms probably alter the level of expression of the ATM, XRCC6 and LIG4 genes, respectively, being important in the maintenance of genomic instability in MDS., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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11. Polymorphisms of DNA repair genes are related to the pathogenesis of myelodysplastic syndrome.
- Author
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Ribeiro HL Jr, de Oliveira RT, Maia AR, Pires Ferreira Filho LI, de Sousa JC, Heredia FF, Magalhães SM, and Pinheiro RF
- Subjects
- Aged, Aged, 80 and over, Female, Genetic Predisposition to Disease, Genotype, Humans, Male, Middle Aged, Myelodysplastic Syndromes pathology, Risk Factors, DNA Repair genetics, Myelodysplastic Syndromes genetics
- Abstract
Some studies show that alterations in DNA repair genes polymorphisms are associated with the pathogenesis and susceptibility of Myelodysplastic Syndrome (MDS). We genotyped 60 MDS patients for six DNA repair gene polymorphisms: BRCA1 rs4793191, BRCA2 rs9567623, RAD51 rs1801320, XRCC5 rs3835, XRCC6 rs2267437 and LIG4 rs1805388. The G/C heterozygote genotype of rs1801320 polymorphism was associated with a decreased chance of developing MDS (p = 0.05). Additionally, the G/G homozygous genotype was associated with the presence of one cytopenia in whole blood. The genotype C/G and CG + GG of the rs2267437 polymorphism was associated with normal karyotype (p = 0.010) and bone marrow cellularity normocellular + hypercellular (p = 0.023). We found that the A/G heterozygous genotype of the rs3835 polymorphism is associated with decreased chance of developing MDS (p < 0.001). These results support the importance of RAD51, XRCC5 and XRCC6 genes polymorphisms in the maintenance of genomic stability promoting a better understanding of the genesis and etiology of MDS., (Copyright © 2014 John Wiley & Sons, Ltd.)
- Published
- 2015
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12. HFE gene mutation and oxidative damage biomarkers in patients with myelodysplastic syndromes and its relation to transfusional iron overload: an observational cross-sectional study.
- Author
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De Souza GF, Ribeiro HL Jr, De Sousa JC, Heredia FF, De Freitas RM, Martins MR, Gonçalves RP, Pinheiro RF, and Magalhães SM
- Subjects
- Adult, Aged, Analysis of Variance, Biomarkers blood, Case-Control Studies, Cross-Sectional Studies, Female, Genotype, Humans, Iron Overload etiology, Male, Middle Aged, Mutation, Myelodysplastic Syndromes blood, Myelodysplastic Syndromes complications, Polymorphism, Restriction Fragment Length, Histocompatibility Antigens Class I genetics, Iron Overload genetics, Myelodysplastic Syndromes genetics, Oxidative Stress genetics
- Abstract
Objective: A relation between transfusional IOL (iron overload), HFE status and oxidative damage was evaluated., Design, Setting and Participants: An observational cross-sectional study involving 87 healthy individuals and 78 patients with myelodysplastic syndromes (MDS) with and without IOL, seen at University Hospital of the Federal University of Ceará, Brazil, between May 2010 and September 2011., Methods: IOL was defined using repeated measures of serum ferritin ≥1000 ng/mL. Variations in the HFE gene were investigated using PCR/restriction fragment length polymorphism (RFLP). The biomarkers of oxidative stress (plasmatic malonaldehyde (MDA), glutathione peroxidase (GPx) and superoxide dismutase (SOD)) were determined by spectrophotometry., Results: The HFE gene variations were identified in 24 patients (30.77%) and 5 volunteers (5.74%). The H63D variant was observed in 35% and the C282Y variant as heterozygous in 5% of patients with MDS with IOL. One patient showed double heterozygous variant (C282Y/H63D) and serum ferritin of 11,649 ng/mL. In patients without IOL, the H63D variant was detected in 29.34%. Serum MDA levels were highest in patients with MDS with IOL, with a significant difference when compared with patients without IOL and healthy volunteers, pointing to the relationship between IOL and oxidative stress. The GPx and SOD were also significantly higher in these patients, indicating that lipid peroxidation increase was followed by an increase in antioxidant capacity. Higher ferritin levels were observed in patients with HFE gene variation. 95.7% of patients with MDS with the presence of HFE gene variations had received more of 20 transfusions., Conclusions: We observed a significant increase in MDA levels in patients with MDS and IOL, suggesting an increased lipid peroxidation in these patients. The accumulation of MDA alters the organisation of membrane phospholipids, contributing to the process of cellular degeneration. Results show that excess iron intensifies the process of cell damage through oxidative stress., Trial Registration Number: Local Ethics Committee (licence 150/2009)., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)
- Published
- 2015
- Full Text
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13. ATM polymorphism is associated with low risk myelodysplastic syndrome.
- Author
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Ribeiro HL Jr, Oliveira RT, Maia AR, Sousa JC, Heredia FF, Magalhães SM, and Pinheiro RF
- Subjects
- Aged, Ataxia Telangiectasia Mutated Proteins, Brazil, Case-Control Studies, Gene Frequency, Heterozygote, Humans, Cell Cycle Proteins genetics, DNA-Binding Proteins genetics, Genetic Predisposition to Disease, Myelodysplastic Syndromes genetics, Polymorphism, Single Nucleotide, Protein Serine-Threonine Kinases genetics, Tumor Suppressor Proteins genetics
- Published
- 2013
- Full Text
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14. Approximate Entropy as a measure of complexity in sap flow temporal dynamics of two tropical tree species under water deficit.
- Author
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Souza GM, Ribeiro RV, Santos MG, Ribeiro HL, and Oliveira RF
- Subjects
- Biological Transport, Spectrum Analysis, Entropy, Plant Physiological Phenomena, Trees metabolism, Water metabolism
- Abstract
Approximate Entropy (ApEn), a model-independent statistics to quantify serial irregularities, was used to evaluate changes in sap flow temporal dynamics of two tropical species of trees subjected to water deficit. Water deficit induced a decrease in sap flow of G. ulmifolia, whereas C. legalis held stable their sap flow levels. Slight increases in time series complexity were observed in both species under drought condition. This study showed that ApEn could be used as a helpful tool to assess slight changes in temporal dynamics of physiological data, and to uncover some patterns of plant physiological responses to environmental stimuli.
- Published
- 2004
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15. Functional groups of forest succession as dissipative structures: an applied study.
- Author
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Souza GM, Ribeiro RV, Santos MG, Ribeiro HL, and Oliveira RF
- Subjects
- Acclimatization physiology, Carbon Dioxide, Photosynthesis physiology, Plant Leaves physiology, Lecythidaceae physiology, Malvaceae physiology, Temperature, Trees
- Abstract
This study tested the hypothesis that dissipative efficiency of tropical tree species could be an ecological advantage in the forest succession process. Daily leaf gas exchanges of a pioneer species (Guazuma ulmifolia) and a late successional species (Cariniana legalis) were evaluated under well-irrigated conditions and by withholding irrigation. Analyses of network connectance (Cg) and plant autonomy (At) were carried out in order to assess metabolic network changes in response to environmental perturbation. As a global estimation of latent heat dissipation, the capacity to both maintain and cool leaf temperature in response to air temperature changes (deltaT = T degrees Cair - T degrees Cleaf) was evaluated. The changes observed in both the systemic parameters (Cg and At) and the physiological ones brought about by water deficit, associated with discrepant growth rates between both species, suggested that the initial formation of gap canopies composed by pioneer species could simply be a result of the higher photosynthetic rates of these species, and not necessarily because late successional species cannot cope with such a heterogeneous environment as that of a gap. Our results indicate that, in the absence of water constraints, the highest CO2 assimilation rates of pioneer species are supported by the efficiency of the whole dissipative structure, involving both degradation and dissipative processes. As a practical result, our study suggests the deltaT analysis in order to evaluate the efficiency of dissipative structures and as a aid in characterizing functional groups.
- Published
- 2004
- Full Text
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