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2.
Sustain Sci ; 17(4): 1301-1316, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35818623

RESUMO

The social and environmental failure of successive Western development models imposed on the global South has led local communities to pursue alternatives to development. Such alternatives seek radical societal transformations that require the production of new knowledge, practices, technologies, and institutions that are effective to achieve more just and sustainable societies. We may think of such a production as innovation driven by social movements, organizations, collectives, indigenous peoples, and local communities. Innovation that is driven by such grassroots groups has been theorized in the academic literature as "grassroots innovation". However, research on alternatives to development has rarely examined innovation using grassroots innovation as an analytical framework. Here, we assess how grassroots innovation may contribute to building alternatives to development using Zapatismo in Chiapas (Mexico) as a case study. We focus on grassroots innovation in autonomous Zapatista education because this alternative to formal education plays a vital role in knowledge generation and the production of new social practices within Zapatista communities, which underpin the radical societal transformation being built by Zapatismo. We reviewed the academic literature on grassroots innovation as well as gray literature and audiovisual media on Zapatismo and autonomous Zapatista education. We also conducted ethnographic fieldwork in a Zapatista community and its school. We found innovative educational, pedagogical, and teaching-learning practices based on the (re)production of knowledge and learning, which are not limited to the classroom but linked to all the activities of Zapatistas. Our findings suggest that innovation self-realized by Zapatistas plays a key role on the everyday construction of Zapatismo. Therefore, we argue that a specific theoretical framework of grassroots innovation for the pluriverse, based on empirical work carried out in different alternatives to development, is an urgent task that will contribute to a better understanding of how such alternatives grassroots groups imagine, design, and build, particularly across the global South.

3.
Sci Rep ; 10(1): 17639, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33057022

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

4.
Polymers (Basel) ; 12(9)2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32948042

RESUMO

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.

5.
Sci Rep ; 10(1): 11637, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32669583

RESUMO

Cellulose nanofibers were obtained from the Colombian fique (Furcraea bedinghausii) and Acrylic hydrogels (H) and reinforced acrylic hydrogels with fique nanofibres (HRFN) were synthesized, using the solution polymerization method. The extraction was carried out using a combined extraction method (chemical procedures and ultrasound radiation). The raw material (NAT-F), bleached fibers (B-F), hydrolyzed fibers and fibers treated with ultrasound (US-F) were characterized by infrared spectroscopy (FTIR) and thermal stability analysis; also, in order to have a comparison criterion, a commercial microcrystalline cellulose sample (CC) was analyzed, which demonstrated the extraction of fique cellulose. The surface morphology of the NAT-F and the B-F was determined by scanning electron microscopy and the average particle size of the nanofibers was made through transmission electron microscopy. In H y HRFN the strain percent and compression resistance (Rc) were measured. The fique nanofibers showed diameter and length averages of 25.2 ± 6.2 nm and 483.8 ± 283.2 nm respectively. Maximum degradation temperature was 317 °C. HRFN presented higher compression resistance (16.39 ± 4.30 kPa) and this resistance was 2.5 greater than the resistance of H (6.49 ± 2.48 kPa). The results indicate that fique lignocellulosic matrix has potential application for obtaining polymeric type composite materials.


Assuntos
Celulose/química , Hidrogéis/química , Magnoliopsida/química , Nanofibras/química , Nanotecnologia/métodos , Colômbia , Força Compressiva , Cristalização , Hidrólise , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Polímeros/química , Pressão , Engenharia de Proteínas , Hidróxido de Sódio/química , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria
6.
J Org Chem ; 85(11): 7368-7377, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32396353

RESUMO

The thermal 6π aza-Diels-Alder cycloadditions between α-oxoketenes, in situ derived from a thermally induced Wolff rearrangement of 2-diazo-1,3-diketones, and N-(5-pyrazolyl)imines as prototypical electron-rich 2-azadienes lead to two distinct sets of products, essentially as a function of the nature of the α-oxoketenes involved. For instance, cyclic five-membered α-oxoketenes lead preferentially to spiro hydropyridin-4-ones, which involves the α-oxoketenes as the 2π partners at their C═C double bond and the N-(5-pyrazolyl)imines as the 4π partners at their 2-azadiene moiety. In contrast, other cyclic and acyclic α-oxoketenes lead preferentially to 1,3-oxazin-4-ones, which now involves the α-oxoketenes as the 4π partners at their 1-oxadiene moiety and the N-(5-pyrazolyl)imines as the 2π partners at their C═N double bond. A computational modeling study using DFT methods allowed rationalizing this change of periselectivity: the formation of spiro hydropyridin-4-ones is under thermodynamic control while the formation of 1,3-oxazin-4-ones is kinetically controlled, and slightly thermodynamically disfavored in the five-membered ring series. The competing cyclodimerization of the α-oxoketenes is also studied in detail.

7.
Comput Biol Chem ; 74: 218-229, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29655025

RESUMO

Given the wide spectrum of biological uses of pyrazolo[1,5-c]quinazoline and spiro-quinazoline derivatives as anticancer, anti-inflammatory analgesic agents, and their therapeutic applications in neurodegenerative disorders, it is compulsory to find easy, efficient, and simple methods to obtain and chemically diversify these families of compounds, thereby improving their biological applications. In this paper, we report the design and eco-friendly two-step synthesis of novel, fused spiro-pyrazolo[1,5-c]quinazoline derivatives as cholinesterase inhibitors. In addition, we studied their protein-ligand interactions via molecular docking and MM/GBSA calculations for a further rational design of more potent inhibitors. In first step, 2-(1H-pyrazol-5-yl)anilines were obtained through microwave (MW) assisted solvent-free/catalyst-free conditions and the second step involved the synthesis of the spiro-pyrazolo[1,5-c]quinazolines by a cyclocondensation reaction between 2-(1H-pyrazol-5-yl)anilines and cyclic ketones, or acetophenones, using stirring at room temperature. The compounds were obtained in high purity, good yields (50-97%), and at varying reaction times. The spiro-compounds were evaluated as acetylcholinesterase and butyrylcholinesterase inhibitors (AChEIs/BuChEIs) respectively, and the most potent compound exhibited a moderate AChE inhibitory activity (5f: IC50 = 84 µM). Molecular docking studies indicated that the binding mode of the compound 5f share common characteristics with the galantamine/donepezil-AChE complexes. Moreover, free binding energy (ΔG) calculations showed a good agreement with the experimental biological activity values. Our theoretical results indicated that halogen bond interactions could be involved with differential potency of these compounds and provide a new starting point to design novel pyrazolo[1,5-c]quinazolines as new anti-Alzheimer agents.


Assuntos
Inibidores da Colinesterase/farmacologia , Desenho de Fármacos , Simulação de Acoplamento Molecular , Pirazóis/farmacologia , Teoria Quântica , Quinazolinas/farmacologia , Compostos de Espiro/farmacologia , Acetilcolinesterase/metabolismo , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Relação Dose-Resposta a Droga , Humanos , Micro-Ondas , Estrutura Molecular , Pirazóis/síntese química , Pirazóis/química , Quinazolinas/síntese química , Quinazolinas/química , Compostos de Espiro/síntese química , Compostos de Espiro/química , Relação Estrutura-Atividade
8.
Ambio ; 47(8): 908-923, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29532402

RESUMO

It has been suggested that traditional ecological knowledge (TEK) may play a key role in forest conservation. However, empirical studies assessing to what extent TEK is associated with forest conservation compared with other variables are rare. Furthermore, to our knowledge, the spatial overlap of TEK and forest conservation has not been evaluated at fine scales. In this paper, we address both issues through a case study with Tsimane' Amerindians in the Bolivian Amazon. We sampled 624 households across 59 villages to estimate TEK and used remote sensing data to assess forest conservation. We ran statistical and spatial analyses to evaluate whether TEK was associated and spatially overlapped with forest conservation at the village level. We find that Tsimane' TEK is significantly and positively associated with forest conservation although acculturation variables bear stronger and negative associations with forest conservation. We also find a very significant spatial overlap between levels of Tsimane' TEK and forest conservation. We discuss the potential reasons underpinning our results, which provide insights that may be useful for informing policies in the realms of development, conservation, and climate. We posit that the protection of indigenous cultural systems is vital and urgent to create more effective policies in such realms.


Assuntos
Conservação dos Recursos Naturais/estatística & dados numéricos , Ecologia/educação , Florestas , Aculturação , Biodiversidade , Bolívia , Estudos Transversais , Meio Ambiente , Características da Família , Humanos , Conhecimento , Análise de Regressão , Análise Espacial
9.
Acta Crystallogr C Struct Chem ; 71(Pt 11): 1028-32, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26524179

RESUMO

Pyrazolo[1,5-c]quinazolines are fused-quinazoline derivatives which have been reported as potential agents against neurological disorders. The normal synthesis routes to these compounds require harsh reaction conditions, long reaction times or multistep sequences. The title compound, C18H15N3S, has been prepared under very mild conditions by condensation of thiochroman-4-one with 5-(2-aminophenyl)-1H-pyrazole, which had itself been prepared by the reaction of hydrazine hydrate with 4-hydroxyquinoline mediated by a brief period of microwave heating. Within the molecule in the crystal structure, the reduced pyrimidine ring adopts an envelope conformation, whereas the thiane ring adopts a half-chair conformation. Molecules are linked into sheets by a combination of one N-H···S hydrogen bond and two independent C-H···π(arene) hydrogen bonds, which utilize the same aryl ring as the acceptor, with one C-H bond donating to each face of the ring. Comparisons are made with some related compounds.

10.
Biol Conserv ; 186: 251-259, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26097240

RESUMO

Understanding how indigenous peoples' management practices relate to biological diversity requires addressing contemporary changes in indigenous peoples' way of life. This study explores the association between cultural change among a Bolivian Amazonian indigenous group, the Tsimane', and tree diversity in forests surrounding their villages. We interviewed 86 informants in six villages about their level of attachment to traditional Tsimane' values, our proxy for cultural change. We estimated tree diversity (Fisher's Alpha index) by inventorying trees in 48 0.1-ha plots in old-growth forests distributed in the territory of the same villages. We used multivariate models to assess the relation between cultural change and alpha tree diversity. Cultural change was associated with alpha tree diversity and the relation showed an inverted U-shape, thus suggesting that tree alpha diversity peaked in villages undergoing intermediate cultural change. Although the results do not allow for testing the direction of the relation, we propose that cultural change relates to tree diversity through the changes in practices and behaviors that affect the traditional ecological knowledge of Tsimane' communities; further research is needed to determine the causality. Our results also find support in the intermediate disturbance hypothesis, and suggest that indigenous management can be seen as an intermediate form of anthropogenic disturbance affecting forest communities in a subtle, non-destructive way.

11.
Landsc Res ; 40(3): 318-337, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25821282

RESUMO

Decisions on landscape management are often dictated by government officials based on their own understandings of how landscape should be used and managed, but rarely considering local peoples' understandings of the landscape they inhabit. We use data collected through free listings, field transects, and interviews to describe how an Amazonian group of hunter-horticulturalists, the Tsimane', classify and perceive the importance of different elements of the landscape across the ecological, socioeconomic, and spiritual dimensions. The Tsimane' recognize nine folk ecotopes (i.e., culturally-recognized landscape units) and use a variety of criteria (including geomorphological features and landscape uses) to differentiate ecotopes from one another. The Tsimane' rank different folk ecotopes in accordance with their perceived ecological, socioeconomic, and spiritual importance. Understanding how local people perceive their landscape contributes towards a landscape management planning paradigm that acknowledges the continuing contributions to management of landscape inhabitants, as well as their cultural and land use rights.

12.
Org Lett ; 16(16): 4126-9, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-25076051

RESUMO

The reactions between electron-rich 2-aza-dienes and α-oxo-ketenes derived from the Wolff rearrangement of 2-diazocycloalkane-1,3-diones chemo- and regioselectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel-Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles.

13.
Molecules ; 19(4): 4284-300, 2014 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-24714191

RESUMO

Diastereoselective reactions between 4-formylpyrazoles, N-substituted maleimides and glycine derivates led to new series of pyrazolyldipyrrolo [3,4-a:3',4'-f]pyrrolizines and pyrazolylpyrrolo[3,4-c]pyrroles in good yields. The reactions proceeded by a domino process through azomethine ylides formed in situ via a 1,3-dipolar cycloaddition reaction.


Assuntos
Pirróis/síntese química , Compostos Azo/química , Catálise , Reação de Cicloadição , Glicina/análogos & derivados , Maleimidas/química , Estrutura Molecular , Estereoisomerismo , Tiossemicarbazonas/química
14.
Econ Bot ; 68(1): 1-15, 2014 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26097243

RESUMO

Researchers have argued that indigenous peoples preferably use the most apparent plant species, particularly for medicinal uses. However, the association between the ecological importance of a species and its usefulness remains unclear. In this paper we quantify such association for six use categories (firewood, construction, materials, food, medicines and other uses). We collected data on the uses of 58 tree species, as reported by 93 informants in 22 villages in the Tsimane' territory (Bolivian Amazon). We calculated the ecological importance of the same species by deriving their importance value index (IVI) in 48 0.1-ha old-growth forest plots. Matching both data sets, we found a positive relation between the IVI of a species and its overall use value (UV) as well as with its UV for construction and materials. We found a negative relation between IVI and UV for species that were reportedly used for medicine and food uses, and no clear pattern for the other categories. We hypothesize that species used for construction or crafting purposes because of their physical properties are more easily substitutable than species used for medicinal or edible purposes because of their chemical properties.

15.
Hum Organ ; 73(2): 162-173, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27642188

RESUMO

Among the different factors associated to change in traditional ecological knowledge, the study of the relations between cultural change and traditional ecological knowledge has received scan and inadequate scholarly attention. Using data from indigenous peoples of an Amazonian society facing increasing exposure to the mainstream Bolivian society, we analyzed the relation between traditional ecological knowledge, proxied with individual plant use knowledge (n=484), and cultural change, proxied with individual- and village-level (n=47) measures of attachment to traditional beliefs and values. We found that both the individual level of detachment to traditional values and the village level of agreement in detachment to traditional values were associated with individual levels of plant use knowledge, irrespective of other proxy measures for cultural change. Because both the individual- and the village-level variables bear statistically significant associations with plant use knowledge, our results suggest that both the individual- and the supra-individual level processes of cultural change are related to the erosion of plant use knowledge. Results from our work highlight the importance of analyzing processes that happen at intermediary social units -the village in our case study- to explain changes in traditional ecological knowledge.

16.
Acta Crystallogr C ; 69(Pt 8): 915-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23907889

RESUMO

In the molecules of both methyl (1RS,3SR,3aRS,6aSR)-1-methyl-3-(3-methyl-1-phenyl-1H-pyrazol-4-yl)-4,6-dioxo-5-phenyloctahydropyrrolo[3,4-c]pyrrole-1-carboxylate, C25H24N4O4, (I), and methyl (1RS,3SR,3aRS,6aSR)-5-(4-chlorophenyl)-1-methyl-3-(3-methyl-1-phenyl-1H-pyrazol-4-yl)-4,6-dioxooctahydropyrrolo[3,4-c]pyrrole-1-carboxylate, C25H23ClN4O4, (II), the two rings of the pyrrolopyrrole fragment are both nonplanar, with conformations close to half-chair forms. The overall conformations of the molecules of (I) and (II) are very similar, apart from the orientation of the ester function. The molecules of (I) are linked into sheets by a combination of an N-H∙∙∙π(pyrrole) hydrogen bond and three independent C-H∙∙∙O hydrogen bonds. The molecules of (II) are also linked into sheets, which are generated by a combination of an N-H∙∙∙N hydrogen bond and two independent C-H∙∙∙O hydrogen bonds, weakly augmented by a C-H∙∙∙π(arene) hydrogen bond.


Assuntos
Pirazóis/química , Pirróis/química , Cristalografia por Raios X , Ligação de Hidrogênio , Espectrometria de Massas , Modelos Moleculares , Conformação Molecular , Pirazóis/síntese química , Pirróis/síntese química
17.
Acta Crystallogr C ; 68(Pt 11): o439-42, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23124458

RESUMO

The racemic title dipyrrolopyrrolizine compound crystallizes from dimethylformamide as a disolvate, C(55)H(39)Cl(2)N(7)O(6)·2C(3)H(7)NO. None of the four fused heterocyclic rings is planar; one adopts an envelope conformation, two others adopt half-chair conformations and the fourth adopts a conformation intermediate between an envelope and a half-chair. The arrangement of the ring fusions is such as to preclude the possibility of internal mirror symmetry. The three independent molecular components are weakly linked by C-H···O hydrogen bonds, and the dipyrrolopyrrolizine molecules are linked by a combination of four C-H···O and one C-H···π(arene) hydrogen bond to form a three-dimensional framework, from which the dimethylformamide solvent molecules are pendent. However, aromatic π-π stacking interactions are absent in the structure.

18.
Acta Crystallogr C ; 66(Pt 10): o521-3, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20921620

RESUMO

Molecules of the title compound, C(9)H(10)N(4)O(3), (I), are linked into complex sheets by a combination of one N-H...O hydrogen bond and two C-H...O hydrogen bonds. Comparisons are drawn between (I) and some related compounds in respect of both their molecular conformations and their hydrogen-bonding arrangements.


Assuntos
Acetamidas/química , Cristalografia por Raios X , Pirimidinas/química , Ligação de Hidrogênio , Modelos Moleculares , Conformação Molecular , Estrutura Molecular
19.
Acta Crystallogr C ; 66(Pt 1): o39-43, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20048422

RESUMO

The bond distances in 2-cyano-N-(2,6-dimethoxypyrimidin-4-yl)-3-[4-(dimethylamino)phenyl]acrylamide, C(18)H(19)N(5)O(3), (I), and in the anionic component of the salt dimethylammonium 6-cyano-1,3-dimethyl-2,4,5-trioxo-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidin-8-ide, C(2)H(8)N(2)(+).C(10)H(7)N(4)O(3)(-), (II), provide evidence for the occurrence of electronic polarization. There are no hydrogen bonds in the structure of (I), instead pairs of molecules are linked into centrosymmetric dimers by a single pi-pi stacking interaction. In (II), a combination of a two-centre N-H...O hydrogen bond, a three-centre N-H...(O)(2) hydrogen bond, together utilizing all three O atoms, and a two-centre C-H...N hydrogen bond, link the components into a ribbon containing R(1)(2)(6), R(2)(2)(10) and R(6)(6)(30) rings.


Assuntos
Acrilamidas/química , Metilaminas/química , Pirimidinas/química , Compostos de Amônio Quaternário/química , Ânions/química , Cristalografia por Raios X , Dimerização , Ligação de Hidrogênio , Modelos Moleculares
20.
Acta Crystallogr C ; 64(Pt 7): o385-7, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18599984

RESUMO

In the title compound, C(14)H(13)N(3)O, the intramolecular distances provide evidence for polarization of the molecular-electronic structure. A single three-centre N-H...(N,O) hydrogen bond links the molecules into chains of edge-fused R(2)(2)(16) and R(2)(4)(12) rings. Comparison with a number of related structures identifies factors of significance controlling the pattern of supramolecular aggregation.


Assuntos
Acrilonitrila/análogos & derivados , Ligação de Hidrogênio , Indóis/química , Acrilonitrila/química , Cristalografia , Estrutura Molecular
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