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1.
Article in Spanish | MEDLINE | ID: mdl-37583450

ABSTRACT

Objective: To describe the quality of life in patients with idiopathic ventricular arrhythmias treated at the Instituto Nacional Cardiovascular INCOR in Lima -Peru. Materials and methods: . Analytical and cross-sectional study of patients with idiopathic ventricular arrhythmias treated by 3D ablation or antiarrhythmic therapy between July 2017 and December 2019 to whom the SF-36 health questionnaire was applied to assess quality of life related to health. Results: Fifty-two patients with idiopathic ventricular arrhythmias were included (34 underwent 3D ablation, and 18 underwent antiarrhythmic therapy only). The percentage of recurrence (14.7% vs. 50%, p=0.01) and adverse effects (0% vs. 22.2%, p=0.011) were lower in the 3D ablation group compared to the antiarrhythmic group. The mean standardized scores obtained from the Spanish version of the Health Survey SF-36v2, applied to the 3D ablation and antiarrhythmic groups were 85.1 vs 68.4 (p<0.001), respectively. Were found statistically significant differences in 6 of the eight components that evaluate health-related quality of life: physical function (96.0 vs. 76.0, p<0.001), physical role (93.4 vs. 61.1, p<0.001), general health (74.5 vs. 47.4, p<0.001), vitality (69.9 vs 54.7, p=0.008), emotional role (92.2 vs. 77.8, p=0.006) and mental health (73.8 vs. 60, p<0.001). Conclusions: Patients with idiopathic ventricular arrhythmias who underwent 3D ablation have a higher mean standardized score for health-related quality of life.

2.
Heliyon ; 9(6): e16782, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37292352

ABSTRACT

Thermoplastic biofilms were developed from achira starch, chitosan and nanoclays using the solvent-casting method. To obtain the filmogenic solutions, different sonication times (0, 10, 20 and 30 min) were considered in order to evaluate the incidence of this parameter on the chemical and physico-mechanical properties of the bionanocomposite films. The chemical analysis using FTIR spectroscopy showed strong intermolecular interactions between the components with increasing sonication times. The results for tensile strength and elongation were satisfactory for films with 20 min of sonication with increases of 154% and 161%, respectively. Morphological analysis showed greater homogeneity, while thermal analysis showed that sonication favoured the plasticization process and thus, the production of homogeneous materials. The water absorption and wettability tests showed less hydrophilic materials allowing these new materials to be considered for use as coatings or packaging for the food sector.

3.
Heliyon ; 8(10): e10833, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36247174

ABSTRACT

Miscibility in biopolymeric blends is a critical process that requires evaluation of the effect of surfactants or coupling agents under conditions similar to processing. Different mixtures in the molten state of plasticized starch and polylactic acid in the presence of a surfactant (Tween 20) at different concentrations were studied. This allowed knowing the rheological, thermal and surface behavior of the mixtures. The results of the dynamic rheological analysis showed increases in viscosity in the presence of the surfactant, in which strong interactions were produced at high shear rates that reflect possible crosslinking between the polymer chains, in addition to intermolecular interactions that were evidenced in the infrared spectrum. Likewise, the storage and loss modulus showed transitions mainly from viscous to elastic typical for thermoplastics. The thermogravimetric analysis did not show significant changes between the mixtures. However, the calorimetric analysis showed changes in the crystallinity of the mixtures, the tensoactive promotes greater freedom of movement and rearrangements in the microstructure with decrease of interface between polymers, and less compaction of the material induced by the emulsion. Analysis derived from biopolymeric films against contact with water shows significant changes. Interaction with water in short times (in the order of minutes) according to the sessile drop technique, favors hydrophilicity by increasing the concentration of Tween 20. However, interaction with water for prolonged times (in the order of hours), shows that the absorption reaches saturation in samples a stabilization in the absorption is observed. The results demonstrate that the miscibility of PLA in AS was achieved in the presence of the tween, under conventional processing conditions. The stability of the different formulations allows the production of films for packaging and biomedical applications.

4.
Polymers (Basel) ; 14(18)2022 Sep 14.
Article in English | MEDLINE | ID: mdl-36145994

ABSTRACT

The use of biopolymers for tissue engineering has recently gained attention due to the need for safer and highly compatible materials. Starch is one of the most used biopolymers for membrane preparation. However, incorporating other polymers into starch membranes introduces improvements, such as better thermal and mechanical resistance and increased water affinity, as we reported in our previous work. There are few reports in the literature on the biocompatibility of starch/chicken gelatin composites. We assessed the in vivo biocompatibility of the five composites (T1-T5) cassava starch/gelatin membranes with subdermal implantations in biomodels at 30, 60, and 90 days. The FT-IR spectroscopy analysis demonstrated the main functional groups for starch and chicken gelatin. At the same time, the thermal study exhibited an increase in thermal resistance for T3 and T4, with a remaining mass (~15 wt.%) at 800 °C. The microstructure analysis for the T2-T4 demonstrated evident roughness changes with porosity presence due to starch and gelatin mixture. The decrease in the starch content in the composites also decreased the gelatinization heats for T3 and T4 (195.67, 196.40 J/g, respectively). Finally, the implantation results demonstrated that the formulations exhibited differences in the degradation and resorption capacities according to the starch content, which is easily degraded by amylases. However, the histological results showed that the samples demonstrated almost complete reabsorption without a severe immune response, indicating a high in vivo biocompatibility. These results show that the cassava starch/chicken gelatin composites are promising membrane materials for tissue engineering applications.

5.
Carbohydr Polym ; 293: 119744, 2022 Oct 01.
Article in English | MEDLINE | ID: mdl-35798436

ABSTRACT

In this work, the miscibility of blends of thermoplastic Achira Starch (AS) and polylactic acid (PLA) was evaluated, assisted by Pluronic® F127 an amphiphilic triblock copolymer that acts as a surfactant and promotes the reduction of surface tension among AS and PLA in solution by emulsion stabilization. Different formulations of AS/PLA blends were obtained at 75:25, 50:50, and 25:75 containing 0 %, 4 %, and 8 % of Pluronic® F127, and glycerol was used as a plasticizer. Solvent casting was the method used to obtain blended polymeric films, which were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), differential scanning calorimetry (DSC) and wettability by contact angle measurements. The results demonstrate that miscibility of PLA in AS or vice versa was achieved. The stability of emulsion and posterior drying of the different formulations allows the production of films for packaging, pharmaceutical, or biomedical applications.


Subject(s)
Poloxamer , Starch , Emulsions , Polyesters , Polymers/chemistry , Starch/chemistry
6.
Polymers (Basel) ; 14(11)2022 May 26.
Article in English | MEDLINE | ID: mdl-35683839

ABSTRACT

Packaging materials play an essential role in the preservation and marketing of food and other products. To improve their conservation capacity, antimicrobial agents that inhibit bacterial growth are used. Biopolymers such as starch and chitosan are a sustainable alternative for the generation of films for packaging that can also serve as a support for preservatives and antimicrobial agents. These substances can replace packaging of synthetic origin and maintain good functional properties to ensure the quality of food products. Films based on a mixture of corn starch and chitosan were developed by the casting method and the effect of incorporating cellulose nanocrystals (CNC) at different concentrations (0 to 10% w/w) was studied. The effect of the incorporation of CNC on the rheological, mechanical, thermal and barrier properties, as well as the antimicrobial activity of nanocomposite films, was evaluated. A significant modification of the functional and antimicrobial properties of the starch-chitosan films was observed with an increase in the concentration of nanomaterials. The films with CNC in a range of 0.5 to 5% presented the best performance. In line with the physicochemical characteristics which are desired in antimicrobial materials, this study can serve as a guide for the development this type of packaging for food use.

7.
Materials (Basel) ; 15(4)2022 Feb 09.
Article in English | MEDLINE | ID: mdl-35207816

ABSTRACT

Packaging materials based on biodegradable polymers are a viable alternative to replace conventional plastic packaging from fossil origin. The type of plasticizer used in these materials affects their functionality and performance. The effect of different plasticizers such as glycerol (GLY), sorbitol (SOR), and poly(ethylene glycol) (PEG) in concentrations of 5%, 10%, and 15% (w/w) on the structural features and functional properties of starch/PVOH/chitosan films was evaluated. The incorporation of a plasticizer increased the thickness of the biodegradable composite films. Furthermore, the material plasticized with 30% (w/w) sorbitol had the highest elongation at break, lowest water vapor permeability, and better thermal resistance. The results obtained in this study suggest that maize starch/PVOH/chitosan biodegradable composite films are a promising packaging material, and that sorbitol is the most suitable plasticizer for this formulation.

8.
Rev Colomb Obstet Ginecol ; 72(3): 271-290, 2021 09 30.
Article in English, Spanish | MEDLINE | ID: mdl-34851570

ABSTRACT

Objective: To report the case of a patient diagnosed with ectopic mammary tissue in the vulva, and to conduct a literature review of the diagnosis, treatment and prognosis of this condition in that location. Materials and Methods: A 49-year-old patient who presented with a painful vulvar mass to a private intermediate complexity center in Bogotá, Colombia. The lesion was assessed on ultrasound and then surgically excised; histopathology showed ectopic mammary tissue with absence of malignancy. A search was conducted in the PubMed, Embase, Cochrane, LILACS and Scielo databases using the keywords "Vulva," "Breast" and "Ectopic." Case reports and case series of women with histopathology-confirmed mammary tissue in the vulva were included. Results: Overall, 184 titles were identified and, of these, 94 were ultimately included, for a total of 126 cases, with 57.9% being benign tumors, 95% in women under 50 years of age, and 42.06% being malignant tumors, 92% in women over 50 years of age. Diagnosis was made on the basis of the clinical findings, with ancillary diagnostic imaging, tumor markers and immunohistochemistry in some cases. Local excision was performed in 91% of cases with benign pathology and in 43% of cases with malignant pathology, with the diagnostic method being therapeutic. Conclusions: Ectopic mammary tissue in the vulva must be considered as part of the differential diagnosis of vulvar masses, prognosis being different in pre and postmenopausal women. Further studies are needed to enhance the characterization of this condition and define the ideal course of treatment in terms of relapse and survival.


Objetivo: reportar el caso de una paciente con diagnóstico de tejido mamario ectópico en vulva, y realizar una revisión de la literatura acerca del diagnóstico, tratamiento y pronóstico de esta condición en esta localización. Materiales y métodos: paciente de 49 años consulta por masa vulvar dolorosa a un centro privado de nivel medio de complejidad ubicado en Bogotá, Colombia. Se realizó ecografía de la lesión y posteriormente escisión quirúrgica; la histopatología mostró tejido mamario ectópico sin malignidad. Se realizó una búsqueda en las bases de datos PubMed, Embase, Cochrane, LILACS y Scielo, con las palabras clave "Vulva", "Glándulas mamarias", "ectópico", "Vulva", "Breast" y "Ectopic", y se incluyeron reportes y series de caso de mujeres con tejido mamario en vulva confirmado por histopatología. Resultados: se identificaron 184 títulos, de los cuales 94 fueron finalmente incluidos para un total de 126 casos. El 57,9% eran tumores benignos, con un 95% en mujeres menores de 50 años; y el 42,06% eran tumores malignos, el 92 % en mujeres mayores de 50 años. El diagnóstico se realizó por clínica, con imágenes diagnósticas complementarias, marcadores tumorales e inmunohistoquímica en algunos casos. Se realizó escisión local en el 91% de los casos de patología benigna y 43% de patología maligna, siendo el método diagnóstico y terapéutico. Conclusiones: el tejido mamario ectópico en vulva debe ser considerado como parte del diagnóstico diferencial de masas a nivel vulvar con diferente pronóstico en mujeres pre y posmenopáusicas. Se requieren más estudios para una mejor caracterización de la patología y definir el tratamiento ideal en términos de recaída y supervivencia.


Subject(s)
Choristoma , Vulvar Diseases , Adult , Breast/diagnostic imaging , Breast/surgery , Choristoma/diagnosis , Choristoma/surgery , Diagnosis, Differential , Female , Humans , Middle Aged , Vulva/surgery , Vulvar Diseases/diagnosis , Vulvar Diseases/surgery
9.
Polymers (Basel) ; 13(24)2021 Dec 17.
Article in English | MEDLINE | ID: mdl-34960981

ABSTRACT

Starch is a biopolymer with enormous potential for generating new biodegradable packages due to its easy availability and low cost. However, due to its weak functional properties, limitation of its interaction with some hydroxyl groups and evaluation of blends with other polymers are necessary in order to improve its performance. Glycerol-plasticized acetylated corn starch films were developed using the casting method, and the impact of incorporating chitosan (TPS:CH) in various proportions (75:25, 50:50, and 25:75 v/v) was studied in the present research. The effect of chitosan ratios on the physical, mechanical, water-vapor barrier, and thermal properties of the film was studied. Chitosan-protonated amino groups promoted the formation of intermolecular bonds, improving tensile strength, thermal stability, hydrophobicity, water adsorption capacity, and the gas barrier of starch films. The results show that the film composed of TPS25-CH75 proved to be the best barrier to water vapor; thus, these composite films are excellent choices for developing biodegradable packaging for the food industry.

10.
Molecules ; 26(21)2021 Nov 07.
Article in English | MEDLINE | ID: mdl-34771143

ABSTRACT

The preparation and characterization of biodegradable films based on starch-PVA-nanoclay by solvent casting are reported in this study. The films were prepared with a relation of 3:2 of starch:PVA and nanoclay (0.5, 1.0, and 1.5% w/v), and glycerol as plasticizer. The nanoclays before being incorporated in the filmogenic solution of starch-PVA were dispersed in two ways: by magnetic stirring and by sonication. The SEM results suggest that the sonication of nanoclay is necessary to reach a good dispersion along the polymeric matrix. FTIR results of films with 1.0 and 1.5% w/v of sonicated nanoclay suggest a strong interaction of hydrogen bond with the polymeric matrix of starch-PVA. However, the properties of WVP, tensile strength, percentage of elongation at break, and Young's modulus improved to the film with sonicated nanoclay at 0.5% w/v, while in films with 1.0 and 1.5% w/w these properties were even worse than in film without nanoclay. Nanoclay concentrations higher than 1.0 w/v saturate the polymer matrix, affecting the physicochemical properties. Accordingly, the successful incorporation of nanoclays at 0.5% w/v into the matrix starch-PVA suggests that this film is a good candidate for use as biodegradable packaging.


Subject(s)
Clay/chemistry , Nanocomposites/chemistry , Polyvinyl Alcohol/chemistry , Optical Imaging , Water/chemistry
11.
Rev. colomb. obstet. ginecol ; 72(3): 271-290, July-Sept. 2021. tab, graf
Article in Spanish | LILACS | ID: biblio-1351952

ABSTRACT

Objetivo: reportar el caso de una paciente con diagnóstico de tejido mamario ectópico en vulva, y realizar una revisión de la literatura acerca del diagnóstico, tratamiento y pronóstico de esta condición en esta localización. Materiales y métodos: paciente de 49 años consulta por masa vulvar dolorosa a un centro privado de nivel medio de complejidad ubicado en Bogotá, Colombia. Se realizó ecografía de la lesión y posteriormente escisión quirúrgica; la histopatología mostró tejido mamario ectópico sin malignidad. Se realizó una búsqueda en las bases de datos PubMed, Embase, Cochrane, LILACS y Scielo, con las palabras clave "Vulva", "Glándulas mamarias", "ectópico", "Vulva", "Breast" y "Ectopic", y se incluyeron reportes y series de caso de mujeres con tejido mamario en vulva confirmado por histopatología. Resultados: se identificaron 184 títulos, de los cuales 94 fueron finalmente incluidos para un total de 126 casos. El 57,9% eran tumores benignos, con un 95% en mujeres menores de 50 años; y el 42,06% eran tumores malignos, el 92 % en mujeres mayores de 50 años. El diagnóstico se realizó por clínica, con imágenes diagnósticas complementarias, marcadores tumorales e inmunohistoquímica en algunos casos. Se realizó escisión local en el 91% de los casos de patología benigna y 43% de patología maligna, siendo el método diagnóstico y terapéutico. Conclusión: el tejido mamario ectópico en vulva debe ser considerado como parte del diagnóstico diferencial de masas a nivel vulvar con diferente pronóstico en mujeres pre y posmenopáusicas. Se requieren más estudios para una mejor caracterización de la patología y definir el tratamiento ideal en términos de recaída y supervivencia.


Objective: To report the case of a patient diagnosed with ectopic mammary tissue in the vulva, and to conduct a literature review of the diagnosis, treatment and prognosis of this condition in that location. Material and methods: A 49-year-old patient who presented with a painful vulvar mass to a private intermediate complexity center in Bogotá, Colombia. The lesion was assessed on ultrasound and then surgically excised; histopathology showed ectopic mammary tissue with absence of malignancy. A search was conducted in the PubMed, Embase, Cochrane, LILACS and Scielo databases using the keywords "Vulva," "Breast" and "Ectopic." Case reports and case series of women with histopathology-confirmed mammary tissue in the vulva were included. Results: Overall, 184 titles were identified and, of these, 94 were ultimately included, for a total of 126 cases, with 57.9% being benign tumors, 95% in women under 50 years of age, and 42.06% being malignant tumors, 92% in women over 50 years of age. Diagnosis was made on the basis of the clinical findings, with ancillary diagnostic imaging, tumor markers and immunohistochemistry in some cases. Local excision was performed in 91% of cases with benign pathology and in 43% of cases with malignant pathology, with the diagnostic method being therapeutic. Conclusion: Ectopic mammary tissue in the vulva must be considered as part of the differential diagnosis of vulvar masses, prognosis being different in pre and postmenopausal women. Further studies are needed to enhance the characterization of this condition and define the ideal course of treatment in terms of relapse and survival.


Subject(s)
Humans , Female , Middle Aged , Vulva , Choristoma , Breast , Review
12.
Polymers (Basel) ; 13(14)2021 Jul 17.
Article in English | MEDLINE | ID: mdl-34301098

ABSTRACT

Biodegradable packaging prepared from starch is an alternative to fossil-based plastic packaging. However, the properties of starch packaging do not comply with the necessary physicochemical properties to preserve food. Hence, in a previous study, we reported the preparation of a composite polymer material based on starch-chitosan-pluronic F127 that was found to be an adequate alternative packaging material. In this study, we modified the physicochemical properties of this material by storing it for 16 months under ambient conditions. The results indicate that the incorporation of pluronic F127 in the blend polymer can help avoid the retrogradation of starch. Moreover, at higher concentrations of pluronic F127, wettability is reduced. Finally, after storage, the materials exhibited surface modification, which is related to a color change and an increase in solubility, as well as a slight increase in stiffness.

13.
Arch Peru Cardiol Cir Cardiovasc ; 2(3): 150-158, 2021.
Article in Spanish | MEDLINE | ID: mdl-37727518

ABSTRACT

Objective: To describe the initial experience in ablation of cardiac arrhythmias using 3D mapping at the Instituto Nacional Cardiovascular INCOR (Lima, Peru). Methods: A retrospective descriptive study was carried out. During February 2020, data was collected from the medical records of all patients in whom ablation was performed using 3D mapping from July 2017 to December 2019. This procedure was performed in patients with symptomatic arrhythmia refractory to antiarrhythmic therapy. Results: Data were collected from 123 patients (median age: 46 years, 64.2% male), who had a median time of illness of 6 years. Among the arrhythmias treated, 19% had atrial fibrillation, 17.5% atrial tachycardia, 17.5% idiopathic ventricular arrhythmias, 16.6% Wolf Parkinson White syndrome / Atrioventricular reentrant tachycardia, 11.1% ventricular arrhythmias of the His-Purkinje conduction system, 9.5% scar related ventricular tachycardia associated, 6.4% atrial flutter and 2.4% intranodal tachycardia. The median fluoroscopy time was 26 minutes. Ablation was acutely successful in 95.9% of cases, acute complications were observed in 4.8%, and recurrence-free survival during the first year of follow-up was 74%. Conclusions: Our experience in ablation of cardiac arrhythmias using 3D mapping had a high acute success rate, low frequency of complications, and one-year recurrence-free survival of 74 %.

14.
Polymers (Basel) ; 12(9)2020 Sep 16.
Article in English | MEDLINE | ID: mdl-32948042

ABSTRACT

One of the critical processing parameters-the speed of the extrusion process for plasticized poly (lactic acid) (PLA)-was investigated in the presence of acetyl tributyl citrate (ATBC) as plasticizer. The mixtures were obtained by varying the content of plasticizer (ATBC, 10-30% by weight), using a twin screw extruder as a processing medium for which a temperature profile with peak was established that ended at 160 °C, two mixing zones and different screw rotation speeds (60 and 150 rpm). To evaluate the thermo-mechanical properties of the blend and hydrophilicity, the miscibility of the plasticizing and PLA matrix, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), oscillatory rheological analysis, Dynamic Mechanical Analysis (DMA), mechanical analysis, as well as the contact angle were tested. The results derived from the oscillatory rheological analysis had a viscous behavior in the PLA samples with the presence of ATBC; the lower process speed promotes the transitions from viscous to elastic as well as higher values of loss modulus, storage modulus and complex viscosity, which means less loss of molecular weight and lower residual energy in the transition from the viscous state to the elastic state. The mechanical and thermal performance was optimized considering a greater capacity in the energy absorption and integration of the components.

15.
Polymers (Basel) ; 12(7)2020 Jun 27.
Article in English | MEDLINE | ID: mdl-32605116

ABSTRACT

This study explores the reprocessing behavior of polypropylene-sugarcane bagasse biocomposites using neat and chemically treated bagasse fibers (20 wt.%). Biocomposites were reprocessed 5 times using the extrusion process followed by injection molding. The mechanical properties indicate that microfibers bagasse fibers addition and chemical treatments generate improvements in the mechanical properties, reaching the highest performance in the third cycle where the flexural modulus and flexural strength increase 57 and 12% in comparison with neat PP. differential scanning calorimetry (DSC) and TGA characterization show that bagasse fibers addition increases the crystallization temperature and thermal stability of the biocomposites 7 and 39 °C respectively, without disturbing the melting process of the PP phase for all extrusion cycles. The rheological test shows that viscosity values of PP and biocomposites decrease progressively with extrusion cycles; however, Cole-Cole plots, dynamic mechanical analysis (DMA), width at half maximum of tan delta peaks and SEM micrographs show that chemical treatments and reprocessing could improve fiber dispersion and fiber-matrix interaction. Based on these results, it can be concluded that recycling potential of polypropylene-sugarcane bagasse biocomposites is huge due to their mechanical, thermal and rheological performance resulting in advantages in terms of sustainability and life cycle impact of these materials.

16.
Data Brief ; 30: 105579, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32382602

ABSTRACT

The article show the date associated with the work previously reported "Design, theoretical and correlation of the electronic and optical properties of diethynylphenylthiophene as photovoltaic materials", https://doi.org/10.1016/j.molstruc.2019.127093[1]. The authors reported graphics and tables building from of p-PDT, m-PDT, o-PDT, p-ZnPDT, m -ZnPDT and o-ZnPDT calculations as raw date, with the aim of to show electronic and optical properties, which can be analyzed by the reader. In this context, there exists an important number of renewable energies that are substituting the oil and the charcoal be used in the energetic supply. One of these alternatives is the use of solar cells, which can be use in diverse areas like telecommunications, remote systems of monitoring, lighting systems, water treatment systems, and products of consumption. The employment of the organic photovoltaic technology and photosensitized organic materials are based on the use of molecular organic materials for coverings for ceiling and windows of a house that allow the storage of energy. The OPVs and DSSC present π conjugated systems, giving them a high electronic relocated density, which allows catching the radiations with an energy range of wavelengths between 400 and 800 nm. The systems are derived of diethynylphenylthiophene (LMWOM) coupled to phenyldiamine (PD) as spacer, forming hyper conjugated macrocycles (p-PDT, m-PDT, o-PDT, p-ZnPDT, m -ZnPDT and o-ZnPDT). On the other hand, it is reported process electronic relationship with material sensitized and the bibliographic support of the publication topic.

17.
Ecol Evol ; 10(4): 1905-1916, 2020 Feb.
Article in English | MEDLINE | ID: mdl-32128124

ABSTRACT

Albizia saman is a multipurpose tree species of seasonally dry tropical forests (SDTFs) of Mesoamerica and northern South America typically cultivated in silvopastoral and other agroforestry systems around the world, a trend that is bound to increase in light of multimillion hectare commitments for forest and landscape restoration. The effective conservation and sustainable use of A. saman requires detailed knowledge of its genetic diversity across its native distribution range of which surprisingly little is known to date. We assessed the genetic diversity and structure of A.saman across twelve representative locations of SDTF in Colombia, and how they may have been shaped by past climatic changes and human influence. We found four different genetic groups which may be the result of differentiation due to isolation of populations in preglacial times. The current distribution and mixture of genetic groups across STDF fragments we observed might be the result of range expansion of SDTFs during the last glacial period followed by range contraction during the Holocene and human-influenced movement of germplasm associated with cattle ranching. Despite the fragmented state of the presumed natural A. saman stands we sampled, we did not find any signs of inbreeding, suggesting that gene flow is not jeopardized in humanized landscapes. However, further research is needed to assess potential deleterious effects of fragmentation on progeny. Climate change is not expected to seriously threaten the in situ persistence of A. saman populations and might present opportunities for future range expansion. However, the sourcing of germplasm for tree planting activities needs to be aligned with the genetic affinity of reference populations across the distribution of Colombian SDTFs. We identify priority source populations for in situ conservation based on their high genetic diversity, lack or limited signs of admixture, and/or genetic uniqueness.

18.
Molecules ; 24(24)2019 Dec 04.
Article in English | MEDLINE | ID: mdl-31817118

ABSTRACT

The modification of achira starch a thermoplastic biopolymer is shown. Glycerol and sorbitol, common plasticizers, were used in the molten state with organic acids such as oleic acid and lactic acid obtaining thermodynamically more stable products. The proportion of starch:plasticizer was 70:30, and the acid agent was added in portions from 3%, 6%, and 9% by weight. These mixtures were obtained in a torque rheometer for 10 min at 130 °C. The lactic acid managed to efficiently promote the gelatinization process by increasing the available polar sites towards the surface of the material; as a result, there were lower values in the contact angle, these results were corroborated with the analysis performed by differential scanning calorimetry and X-ray diffraction. The results derived from oscillatory rheological analysis had a viscous behavior in the thermoplastic starch samples and with the presence of acids; this behavior favors the transitions from viscous to elastic. The mixture of sorbitol or glycerol with lactic acid promoted lower values of the loss module, the storage module, and the complex viscosity, which means lower residual energy in the transition of the viscous state to the elastic state; this allows the compounds to be scaled to conventional polymer transformation processes.


Subject(s)
Lactic Acid/chemistry , Oleic Acid/chemistry , Plastics/chemistry , Rheology , Starch/chemistry , Temperature , Calorimetry, Differential Scanning , Elastic Modulus , Spectrophotometry, Ultraviolet , Starch/ultrastructure , Thermogravimetry , Torque , Viscosity , X-Ray Diffraction
19.
PLoS One ; 12(8): e0183743, 2017.
Article in English | MEDLINE | ID: mdl-28837638

ABSTRACT

Understanding the factors that underlie the production of non-timber forest products (NTFPs), as well as regularly monitoring production levels, are key to allow sustainability assessments of NTFP extractive economies. Brazil nut (Bertholletia excelsa, Lecythidaceae) seed harvesting from natural forests is one of the cornerstone NTFP economies in Amazonia. In the Peruvian Amazon it is organized in a concession system. Drawing on seed production estimates of >135,000 individual Brazil nut trees from >400 concessions and ethno-ecological interviews with >80 concession holders, here we aimed to (i) assess the accuracy of seed production estimates by Brazil nut seed harvesters, and (ii) validate their traditional ecological knowledge (TEK) about the variables that influence Brazil nut production. We compared productivity estimates with actual field measurements carried out in the study area and found a positive correlation between them. Furthermore, we compared the relationships between seed production and a number of phenotypic, phytosanitary and environmental variables described in literature with those obtained for the seed production estimates and found high consistency between them, justifying the use of the dataset for validating TEK and innovative hypothesis testing. As expected, nearly all TEK on Brazil nut productivity was corroborated by our data. This is reassuring as Brazil nut concession holders, and NTFP harvesters at large, rely on their knowledge to guide the management of the trees upon which their extractive economies are based. Our findings suggest that productivity estimates of Brazil nut trees and possibly other NTFP-producing species could replace or complement actual measurements, which are very expensive and labour intensive, at least in areas where harvesters have a tradition of collecting NTFPs from the same trees over multiple years or decades. Productivity estimates might even be sourced from harvesters through registers on an annual basis, thus allowing a more cost-efficient and robust monitoring of productivity levels.


Subject(s)
Conservation of Natural Resources , Crowdsourcing , Forests , Lecythidaceae/embryology , Seeds , Peru
20.
J Phys Chem A ; 118(1): 197-207, 2014 Jan 09.
Article in English | MEDLINE | ID: mdl-24350909

ABSTRACT

A density functional theory study was performed to analyze the electron donor-acceptor properties of the cis and trans isomers of a novel azobenzene-containing tetraphenylporphyrin (TPPN2PhC14H29) with different substituents (Br or TMS). In general, the trans isomers are better electron acceptors than the correspondent cis homologues. Their UV-vis spectra were also obtained and a comparison with available experimental results is included. According to these results, the azo compounds reported here are promising materials for the elaboration of dye-sensitized solar cells because their HOMO-LUMO gaps are close to 2 eV. Moreover, the energy of the high intensity absorption bands also fulfills the requirements needed for the operation of a solar cell built with TiO2 and the I(-)/I3(-) pair.

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