RESUMO

Using biopolymers functionalized with antibacterial agents to manufacture active packaging is a clean alternative to mitigate food losses due to postharvest plant diseases. In this study, two mycosynthetized AgNPs impregnation methodologies on cotton (cationization and in situ biochemical reduction) were used to obtain the antibacterial fibers (A-AgNPs-C and A-AgNPs-IBR), which, in addition to being characterized by SEM-EDX, XRD, were evaluated as antibacterial materials. The cotton fibers showed growth inhibition of Pectobacterium carotovorum at 48 h. The reuse tests of these cotton fibers showed that the two types of fibers could have up to three successive uses without losing their effectiveness, regardless of the impregnation method used. Is important to highlight that the retention tests indicated that the AgNPs remain attached to the A-AgNPs-C and A-AgNPs-IBR fibers after several successive washes. Finally, the mycosynthesized AgNPs were also impregnated on fique fibers (Fique-AgNPs) by cationization to obtain little antibacterial sacks. Nanostructured materials that in in vivo tests on potatoes showed only 7.8 % of affectation, while the tubers stored in the traditional sacks had an affectation of 25 %. This immobilization of AgNPs in natural fibers will allow the development of a nanobiotechnological application in the storage and transport of potatoes, after performing some additional cytotoxicity tests to guarantee its safety.

RESUMO

To achieve a suitable packaging configuration, it is important first to determine the physicochemical characteristics related to the packaged product. In this study, the physicochemical characterization of fresh purple passion fruits of three different ripening stages was carried out to determine key variables for the packaging, such as O2 consumption and CO2 -ethylene production rates. Subsequently, intermediate-ripe fruits were packaged for 21 days at 6 °C under three packaging conditions: Xtend® perforated bags, low-density polyethylene (LDPE) bags, and LDPE bags with a novel ethylene scavenger active additive (ESAA). It was observed that an equilibrium modified atmosphere was formed in the packages. For the Xtend® bags, the highest values of O2 (yo2  = 0.184 to 0.192) and lowest of CO2 (yco2  = 0.033 to 0.041) were reached, whereas for the LDPE bags with ESAA these values were moderate. In the case of ethylene, the LDPE bags showed the highest levels in the headspace (26 to 31 ppm), whereas the lowest levels were obtained in the LDPE bags with additive (2 to 4 ppm). These levels resulted in a delay in the ripening of the fruits during storage, which was verified through a sensory acceptability test that was carried out on the juice extracted from the fruits. In this sensory test, panelists identified similar characteristics between the fruits packaged with ESAA and the Xtend® bags, regarding the control fruits. The LDPE bags with the ethylene scavenger performed satisfactorily and can considerably delay the ripening, which may result in longer shelf life and conservation of fresh purple passion fruits. PRACTICAL APPLICATION: This work presents a novel packaging proposal that reduces oxygen and ethylene levels in contact with purple passion fruits. Our proposed active packaging can be used to increase the fruit shelf life by improving its conservation conditions throughout the chain of storage, transport, and distribution in the market. With this, it will be possible to reduce the fruit's losses due to senescence and to reduce the substrate consumption by using a more effective packaging system.

Assuntos

RESUMO

Resumen After an internal conflict that lasted over half a century, the detection and removal of antipersonnel landmines in Colombia have become cumbersome challenges. Antipersonnel landmines remain scattered in Colombia and with a considerable impact on the central-western region. Most of these devices are handmade (therefore, they can also be classified as improvised explosive devices) and composed of ammonium nitrate and fossil fuel blend, a mixture known as ANFO. Due to several unique factors, including concealment tactics and non-conventional manufacturing techniques employed by guerrilla fighters, the most efficient method for the detection of ANFO-based antipersonnel landmines is the use of trained canines. This review aims at describing the current chemical strategies used in the detection of ANFO-based antipersonnel landmines. First, a detailed description of the different techniques used in the detection of explosives is made. Then, all the strategies reported in the world for antipersonnel landmines detection are described. Finally, the importance of the use of canines for antipersonnel landmines detection is explained.

Abstract Después de un conflicto interno que duró más de medio siglo, la detección y eliminación de minas antipersonales en Colombia se han convertido en desafíos engorrosos. Las minas antipersonales siguen dispersas en la región centro-occidental de Colombia. La mayoría de estos dispositivos están hechos a mano (hecho que puede clasificarlos como artefactos explosivos improvisados, AEI) y están compuestos por una mezcla de nitrato de amonio y un combustible fósil, una mezcla conocida como ANFO. Debido a varios factores únicos, que incluyen tácticas de ocultación y técnicas de fabricación no convencionales empleadas por guerrilleros, el método más eficiente para la detección minas antipersonales basadas en ANFO es el uso de caninos entrenados. Esta revisión tiene como objetivo describir las estrategias químicas actuales utilizadas en la detección de minas antipersonales basadas en ANFO. En primer lugar, se hace una descripcion detallada de las diferentes técnicas utilizadas en la detección de explosivos; luego, se describen todas las estrategias reportadas en el mundo para la detección de minas antipersonales y, finalmente, se explica la importancia del uso de caninos para la detección de minas antipersonales.

Resumo Após um conflito interno que durou mais de meio século, a detecção e remoção de minas antipessoal na Colômbia se tornaram desafios complexos. As minas antipessoal continuam espalhadas na região centro-oeste da Colômbia. A maioria desses dispositivos é feita à mão (fato que pode classificá-los como dispositivos explosivos improvisados, DEI) e composta de uma mistura de nitrato de amônio e um combustível fóssil - uma mistura conhecida como ANFO. Devido a vários fatores únicos, incluindo táticas de ocultação e técnicas de fabricação não convencionais empregadas por guerrilheiros, o método mais eficiente para a detecção de minas antipessoal baseadas em ANFO é o uso de caninos treinados. Esta revisão visa descrever as estratégias químicas atuais usadas na detecção de minas antipessoal baseadas em ANFO. Primeiro, é feita uma descrição detalhada das diferentes técnicas utilizadas na detecção de explosivos; Em seguida, são descritas todas as estratégias relatadas no mundo para a detecção de minas antipessoal e, finalmente, é explicada a importância do uso de caninos para a detecção de minas antipessoal.

RESUMO

Ammonium nitrate fuel oil is an explosive mixture found in most antipersonnel landmines (APL) buried throughout the Colombian territory. During more than 50 years of internal conflict, the Colombian government has found that trained dogs are the most effective method to detect APL. However, the olfactive signature in ANFO is unknown and also if there are differences in detection related to the explosive manufacturing origin. Therefore, this work begins with the analytical validation of the method used to determine ammonia, in its derivatized form as carbamate, released by home-made ANFO using HS-SPME-GC-FID. Once validated, the method was used to identify ammonia and other organic volatile compounds present in ANFO, under laboratory and simulated field conditions. The validation process includes the evaluation of the optimum conditions for the derivation and extraction of butylcarbamate, the determination of the working ranges with linear response in FID, the limits of detection and quantification, the sensitivity, and the precision. The results of the validation established linearity and sensitivity in a concentration between 20 and 120 mg/L, as well as low limits of detection and quantification of 6.4 and 21.4 mg/L, respectively. Also, an intermediate precision of 11% for butylcarbamate with a repeatability of 8%. The validated method showed in real samples of home-made ANFO besides ammonia, the presence of low molecular methylamines, and also exhibited differences in volatile compositions according to the origin. The objective of this work is to offer a reliable analytical methodology for the extraction and analysis of volatile compounds from ANFO.

RESUMO

Two Covalent Organic Frameworks (COF), named TFP-BZ and TFP-DMBZ, were synthesized using the imine condensation between 1,3,5-triformylphloroglucinol (TFP) with benzidine (BZ) or 3,3-dimethylbenzidine (DMBZ). These materials were deposited, such as films over interdigitated electrodes (IDE), by chemical bath deposition, giving rise to TFP-BZ-IDE and TFP-DMBZ-IDE systems. The synthesized COFs powders were characterized by Powder X-Ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FT-IR), solid-state Nuclear Magnetic Resonance (ssNMR), nitrogen adsorption isotherms, Scanning Electron Microscopy (SEM), and Raman spectroscopy, while the films were characterized by SEM and Raman. Ammonia and low molecular weight amine sensing were developed with the COF film systems using the impedance electrochemical spectroscopy (EIS). Results showed that the systems TFP-BZ-IDE and TFP-DMBZ-IDE detect low molecular weight amines selectively by impedimetric analysis. Remarkably, with no significant interference by other atmospheric gas compounds such as nitrogen, carbon dioxide, and methane. Additionally, both COF films presented a range of sensitivity at low amine concentrations below two ppm at room temperature.

RESUMO

In this contribution, we examine the photophysical properties of 15 totally trans-trans 1,4-distyrylbenzene derivatives (DSBs) functionalized with different electron-donating (ED) and electron-withdrawing (EW) groups by experimental and computational methodologies. We use UV-vis and fluorescence spectroscopies to determine the experimental optical properties such as the maximum absorption (λabsexp) and emission (λemexp) wavelengths, the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gaps (ΔEabsexp), the molar extinction coefficients (ε), the fluorescence quantum yields (Φf), and the fluorescence lifetimes (τ). We also calculate the experimental spontaneous emission decay rate (krexp) and correlate all of these magnitudes to the corresponding calculated properties, maximum absorption (λabscal) and emission (λemcal) wavelengths, vertical transition energies (ΔEabscal), oscillator strength (Fosc), and spontaneous emission decay rate (krcal), obtained by the time-dependent density functional theory method. We analyze the effect of the electronic nature of the substituents on the properties of the DSBs, finding that the ED and EW groups lead to bathochromic shifts. This is consistent with the decrease of ΔE values as the strength of ED and EW substituents increases. We find excellent correlations between calculated and experimental values for λabs, λem, and ΔEabs (r ∼ 0.99-0.95). Additionally, the correlations between the relative ε with Fosc values and the kr values are in good agreement (r ∼ 0.88-0.72) with the experimental properties. Overall, we find that for substituted 1,4-DSBs, computational chemistry is an excellent tool to predict structure-property relationships, which can be useful to forecast the properties of their polymeric analogues, which are usually difficult to determine experimentally.

RESUMO

RESUMEN En años recientes hubo un auge del uso de terapias génicas para el tratamiento de enfermedades de gran incidencia, como el cáncer. Generalmente, estas se basan en la liberación de material genético como plásmidos, en el núcleo celular, con lo cual se corrige una función o se induce la producción de proteínas deficientes a nivel fisiológico. Para llevar a cabo la terapia génica se requiere de vectores capaces de encapsular el material genético y garantizar su entrega en el núcleo celular. Los polímeros catiónicos sintéticos han llamado la atención como vectores, debido a su capacidad de condensar ácidos nucleicos para formar partículas que los protegen de la degradación enzimática y facilitan su captación celular. La polietilenimina y el polimetacrilato de N, N-dimetilaminoetilo son los polímeros catiónicos más eficaces para la administración génica. Sin embargo, estos requieren modificaciones químicas específicas para eliminar o disminuir algunas limitaciones tales como su alta citotoxicidad y baja biodegradabilidad. En este artículo se analizan algunas de estas modificaciones, enfocándose en avances recientes en el desarrollo de copolímeros anfifílicos como precursores de nanopartículas usadas como vectores génicos.

SUMMARY During recent years, the use of genetic therapies has taken relevance in the treatment of high-incidence diseases such as cancer. Usually, they are based on the release of genetic material, as plasmids, into the cell nucleus, which corrects a function or induces the production of a deficient protein at the physiological level. To carry out gene therapy, vectors capable of encapsulating the genetic material and guaranteeing its delivery in the target cell nucleus are required. Synthetic cationic polymers have attracted great attention as vectors due to their ability to condense nucleic acids to form particles that protect them from enzymatic degradation and facilitate their cellular uptake. Polyethylenimine and poly (N, N-dimethylaminoethyl methacrylate) are the most effective cationic polymers for gene delivery. However, these polymers require specific chemical modifications to either avoid or diminish their high cytotoxicity and low biodegradability. This review analyzes some of these modifications, focusing on recent advances in the development of amphiphilic copolymers as precursors of nanoparticles used as gene vectors.

RESUMO

Abstract The synthesis of new terpyridine (Tpy) derivatives has been subject of extensive research due to its potential as functional materials for solar energy conversion, among other applications. In this contribution, the 4-([2,2':6',2"-terpyndm]-4'-yl)phenol (TpyOH) was synthesized, characterized and studied through several methods, including X-ray crystallography and computational approaches. Single crystal X-ray structure analysis shows that TpyOH is essentially planar, with dihedral angles of about 5.03° between the central pyridinyl and the phenolic ring, and also 6.05 and 12.2° in the terpyridine moiety. In the crystal, molecules are linked by intermolecular hydrogen bonds and through П- П stacking interactions. Using a time dependent density functional theory approach and taking into account bulk solvent effects, the absorption and fluorescence spectra of TpyOH were investigated and compared. The TD-DFT S0→Sn and S1 →S0 transition energies are in good agreement with experimental results. The frontier molecular orbitals analysis showed that the low-energy absorption band has an intraligand charge transfer character (ICT), while the high-energy band is a common feature of П- П* transitions of the Tpy moiety. The S1→S0 emission transition also has an ICT character, with a 90% contribution from the HOMO→LUMO transitions.

Resumen La síntesis de derivados terpiridinicos (Tpy) se ha investigado ampliamente debido a su potencial para la conversión de energía solar En este artículo se sintetizó y caracterizó el 4-([2,2':6',2"-terpiridin]-4'-il)fenol (TpyOH), a través de varias metodologías como la cristalografía de rayos X y herramientas computacionales. El análisis de rayos X de monocristal mostró que el TpyOH es plano, con ángulos diedros de 5,03° entre el piridinilo central y el anillo fenólico, con presencia de ángulos de 6,05 y 12,2° en la porción terpiridínica. En el cristal, las moléculas están unidas por enlaces de hidrógeno intermoleculares y mediante interacciones de apilamiento n-n. Utilizando cálculos DFT dependientes del tiempo (TD-DFT) y teniendo en cuenta el efecto de los disolventes, se investigaron y compararon los espectros de absorción y fluorescencia de TpyOH. Las energías de transición TD-DFT de S0→Sn y S1→S0 concuerdan con los resultados experimentales. El análisis de orbitales moleculares de frontera mostró que la banda de absorción de baja energía corresponde a transferencia de carga intraligando (ICT); mientras que la banda de alta energía es común en las transiciones П-П* del resto Tpy. La emisión debido a la transición S1→S0 corresponde a ICT, con una contribución del 90% proveniente de transiciones HOMO→LUMO.

Resumo A síntese de derivados de terpiridina (Tpy) tem sido estudada devido ao seu potencial para a conversão de energia solar. Nesta contribuição, o 4-([2,2':6',2"- terpindina]-4'-il) fenol (TpyOH) foi sintetizado, caracterizado e estudado por vários métodos A análise de estrutura de raios X de cristal único mostra que o TpyOH é plano, com Ångulos diedros de 5,03 ° entre o piridinilo central e o anel fenólico, e também 6,05 e 12,2 ° na porção de terpiridina No cristal, as moléculas são ligadas por ligações intermoleculares de hidrogênio e através de interações de empilhamento n-n. Usando uma abordagem da teoria funcional da densidade dependente do tempo e levando em consideração os efeitos do solvente em massa, foram investigados e comparados os espectros de absorção e fluorescência do TpyOH As energias de transição TD-DFT S0→Sn e S1→S0 estão de acordo com os resultados experimentais A análise de orbitários moleculares de fronteira mostrou que a banda de absorção de baixa energia possui um caráter de transferência de carga intraligando (TIC), enquanto a banda de alta energia é uma característica comum das transições П-П* da fração Tpy. A transição de emissão S1→S0 também tem um caráter TIC, com uma contribuição de 90% das transições HOMO→LUMO.

RESUMO

En Colombia existe una diversidad de ovinos, denominados ovinos criollos, resultado del cruce de diferentes razas, desde la época de la colonización y que se adaptaron a diferentes regiones del país. En el caso particular de este estudio, se hace referencia a los ovinos criollos de pelo, que se acomodaron a las condiciones biogeográficas de la Costa Caribe colombiana. Estos animales, por su adaptabilidad, han tenido un importante papel en el desarrollo de la ovinocultura del país; sin embargo, es muy poca la información que se tiene, a nivel nacional, sobre las características crecimiento de la raza o especie. El objetivo del presente estudio fue determinar la curva de crecimiento de dos poblaciones de ovinos criollos del trópico bajo colombiano, a través del uso del modelo no lineal Gompertz. Se utilizaron 55 animales, con 13 pesajes cada uno, perteneciente a dos sistemas de producción del departamento de Córdoba, Colombia. Se realizó un ajuste del modelo, mediante el procedimiento NLIN de Statistical Analysis Software (SAS), para la estimación de los parámetros del modelo. Se estimó β0, β1 y β2, cuyos valores fueron 25,97 ± 9,3, 2,1 ± 0,5 y 0,010 ± 0,004, respectivamente. Los estimados de madurez a los 4 y 6 meses fueron de 55,8 y 70,6%, respectivamente, y la edad al 75 de madurez fue de 7,0 meses y al 95% de madurez, de 13,1 meses. El modelo de Gompertz permitió describir el crecimiento de ovinos criollos, en condiciones de pastoreo, en el trópico bajo.

The Colombian Creole sheep has an important role in the development of sheep farming in the country, as this breed is distributed in most of the territory, being animals with significant features that make it widely used in farms with different productive purposes. To assess growth characteristics in animals have been used mathematical models, which describe the relationship between the age of the animal, its rate of growth and maturity. These models are equations that allow the construction of continuous curves of one biological variable according to another. This study aimed to determine the growth curve of two populations of crossbred sheep through the use of nonlinear Gompertz model. 55 animals with 13 measures of weight each were used, pertaining to two production systems of the department of Córdoba, Colombia. Estimaste for β0, β1 y β2 were 25.97 ± 9.3, 2.1 ± 0.5 and 0.010 ± 0.004, respectively. Estimates of maturity at 4 and 6 months were 55.8 and 70.6%, respectively; age 75% of maturity was of 7.0 months and at 95% of maturity was of 13.1 months. Gompertz model allowed describing the growth of creole sheep in conditions of grazing in the low tropics.

RESUMO

In the title compound, C10H9NO2S, all the non-H atoms, except for the ethyl fragment, lie nearly in the same plane. Despite the mol-ecular planarity, the ethyl fragment presents more than one conformation, giving rise to a discrete disorder, which was modelled with two different crystallographic sites for the eth-oxy O and eth-oxy α-C atoms, with occupancy values of 0.5. In the crystal, the three-dimensional array is mainly directed by C-H⋯(O,N) inter-actions, giving rise to inversion dimers with R22(10) and R22(14) motifs and infinite chains running along the [100] direction.

RESUMO

Phenylenevinylene oligomers (PVs) have outstanding photophysical characteristics for applications in the growing field of organic electronics. Yet, PVs are also versatile molecules, the optical and physicochemical properties of which can be tuned by manipulation of their structure. We report the synthesis, photophysical, and MS characterization of eight PV derivatives with potential value as electron transfer (ET) matrices for UV-MALDI. UV-vis analysis show the presence of strong characteristic absorption bands in the UV region and molar absorptivities at 355 nm similar or higher than those of traditional proton (CHCA) and ET (DCTB) MALDI matrices. Most of the PVs exhibit non-radiative quantum yields (φ) above 0.5, indicating favorable thermal decay. Ionization potential values (IP) for PVs, calculated by the Electron Propagator Theory (EPT), range from 6.88 to 7.96 eV, making these oligomers good candidates as matrices for ET ionization. LDI analysis of PVs shows only the presence of radical cations (M+.) in positive ion mode and absence of clusters, adducts, or protonated species; in addition, M+. threshold energies for PVs are lower than for DCTB. We also tested the performance of four selected PVs as ET MALDI matrices for analytes ranging from porphyrins and phthalocyanines to polyaromatic compounds. Two of the four PVs show S/N enhancement of 1961% to 304% in comparison to LDI, and laser energy thresholds from 0.17 µJ to 0.47 µJ compared to 0.58 µJ for DCTB. The use of PV matrices also results in lower LODs (low fmol range) whereas LDI LODs range from pmol to nmol. Graphical Abstract ᅟ.

RESUMO

In the title compounds, N-(5-acetyl-2-methyl-phen-yl)quinoline-2-carboxamide [C19H16N2O2, (I)], N-(5-acetyl-2-bromo-phen-yl)quinoline-2-carboxamide [C18H13BrN2O2, (II)] and N-(5-acetyl-2-ethynylphen-yl)quinoline-2-carboxamide [C20H14N2O2, (III)], the quinoline ring system is essentially planar and forms a dihedral angles of 3.68 (5) (I), 5.59 (7) (II) and 1.87 (6)° (III) with the acetyl-substituted ring. The mol-ecular structures of (I) and (III) each feature an intra-molecular N-H⋯N hydrogen bond, forming an S(5) ring, while in (II) an intra-molecular bifurcated N-H⋯(N,Br) hydrogen bond forms two S(5) rings. In the crystals, weak C-H⋯O hydrogen bonds link mol-ecules of (I) into C(7) chains long [010], mol-ecules of (II) into chains of R22(8) rings along [110] and mol-ecules of (III) into C(8) chains along [010]. In (I), there are no significant π-π stacking inter-actions under 4 Å, but in both (II) and (III), π-π inter-actions link the weak hydrogen-bonded chains into layers parallel to (001) [centroid-centroid disttances of 3.748 (1) Šin (II) and 3.577 (1), 3.784 (1) and 3.780 (1) Šin (III)].

RESUMO

In the title compound, C25H16N2O2, the quinoline ring system is essentially planar, with a maximum deviation of 0.030 (1) Å, and forms a dihedral angle of 20.9 (1)° with benzoyl benzene ring. The unsubstituted phenyl ring forms dihedral angles of 52.7 (1)° with the quinoline ring system and 54.1 (1)° with the ethynyl-substituted benzene ring. The mol-ecule contains an intra-molecular bifurcated N-H⋯(O,N) hydrogen bond, forming S(5) and S(6) rings, which may influence the conformation of the mol-ecule. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into a three-dimensional network. In addition, the three-dimensional structure contains π-π stacking inter-actions, with centroid-centroid distances of 3.695 (1) and 3.751 (1) Å.

RESUMO

Multidrug resistance (MDR) in cancer cells is the development of resistance to a variety of structurally and functionally nonrelated anticancer drugs. This phenomenon has become a major obstacle to cancer chemotherapy seriously affecting the clinical outcome. MDR is associated with increased drug efflux from cells mediated by an energy-dependent mechanism involving the ATP-binding cassette (ABC) transporters, mainly P-glycoprotein (ABCB1), the MDR-associated protein-1 (ABCC1), and the breast cancer resistance protein (ABCG2). The first two transporters have been widely studied already and reviews summarized the results. The ABCG2 protein has been a subject of intense study since its discovery as its overexpression has been detected in resistant cell lines in numerous types of human cancers. To date, a long list of modulators of ABCG2 exists and continues to increase. However, little is known about the clinical consequences of ABCG2 modulation. This makes the design of novel, potent, and nontoxic inhibitors of this efflux protein a major challenge to reverse MDR and thereby increase the success of chemotherapy. The aim of the present review is to describe and highlight specific and nonspecific modulators of ABCG2 reported to date based on the selectivity of the compounds, as many of them are effective against one or more ABC transport proteins.

Assuntos

RESUMO

The use of water hyacinth's dried matter (Eichhornia crasippes) as a support matrix for nano-MnO2 and its application for the removal of indigo carmine RIC) was studied. Different pretreatment processes were tested and results indicated that an acid-alkali pretreatment is an efficient method to binding nanoparticles RNPs) to cellulosic matrix. In adittion, the MnO2 NPs were synthesized by sonochemical reduction of MnO4- using different methods Rultrasonic horn system, ultrasonic bath and reaction with ethanol), where the influence of the precursor concentration was observed. The synthesized material was further characterized by ATR-IR, AAS, XRD, SEM, nitrogen isotherms adsorption, EDS, and pHpzc. The IC removal capacity of the nanostructured material, the chemical nature of the degradation products and the effect of various parameters Rtemperature, pH, initial IC concentration, among others) were explored in water samples.

Se estudió el uso de la materia seca del jacinto de agua (Eichhornia crassipes) como matriz-soporte para nano-MnO2 y su eficiencia en la eliminación de índigo carmín RIC). Se ensayaron diferentes procesos de pretratamiento y los resultados indicaron que un tratamiento previo ácido-alcalino es un método eficiente para unir las nanopartículas (NPs) a la matriz celulósica. Así mismo, las NPs de MnO2 se sintetizaron por reducción sonoquímica de MnO4- utilizando diferentes métodos Run sistema emisor de ultrasonido, baño de ultrasonido y reacción convencional con etanol como medio). El material sintetizado se caracterizó por ATR-IR, AAS, DRX, SEM, isotermas de adsorción de nitrógeno, EDS y pHpzc. Se exploró la capacidad de eliminación de IC por parte del material nanoestructurado y la naturaleza química de los productos de degradación en muestras acuosas. Se analizó el efecto de diversos parámetros tales como temperatura, pH, concentración inicial de IC, entre otros.

Foi estudada a utilização de matéria seca de jacinto de água (Eichhornia crassipes) como matriz de suporte para nano-MnO2 e sua aplicação para a remoção de índigo carmine RIC). Diferentes processos de prétratamento foram testados e os resultados indicaram que o prétratamento ácido-álcali é um método eficiente para ligar os NPs à matriz celulósica. Além disso, as NPs de MnO2 foram sintetizados por redução sonoquímica de MnO4- utilizando diferentes métodos (um sistema emissor de ultrassom, banho de ultrassom e a reacção com o etanol). O material sintetizado foi caracterizado por ATR-IR, AAS, DRX, SEM, isotermas de adsorção de nitrogênio, EDS e pHpzc. A facilidade de remoção de IC por o material nanoestruturado e a natureza química da degradação dos produtos foram explorados em amostras aquosas, assim mesmo foi estudado o efeito de vários parâmetros Rtemperatura, pH, concentração inicial de IC e a quantidade de nanocompósito, entre outros).

RESUMO

Debido a la creciente producción y uso de nanomateriales para actividades de investigación y desarrollo en Colombia, es necesario establecer una definición del término nanomaterial que facilite la toma de decisiones en torno a iniciativas de carácter regulatorio y de normatividad. Se presenta la definición de nanomateriales para Colombia que ha adoptado el Consejo Nacional Asesor de Nanociencia y Nanotecnología adscrito a la Red Colombiana de Nanociencia y Nanotecnología.

Due to the increasing production and use of nanomaterials in research and development activities in Colombia, it is necessary to define the nanomaterial term in order to facilitate decision-making process regarding initiatives with a regulatory or normative character. This article presents the nanomaterials definition that has been adopted by the National Advisory Council for Nanoscience and Nanotechnology, a Colombian Network of Nanoscience and Nanotechnology.

Dada a crescente produção e utilização de nanomateriais para a pesquisa e desenvolvimiento na Colombia, é urgente estabelecer uma definição do termo de nanomaterial para facilitar a tomada de decisão sobre iniciativas na regulamentação e as leis. É apresentada uma definição de nanomateriais para a Colombia que aprovou o Conselho Consultivo Nacional de Nanociência e Nanotecnologia ligado à Rede Colombiana de Nanociência e Nanotecnologia.

RESUMO

A simple, convenient and environmentally friendly one-pot procedure for the synthesis of 1,8-dioxo-octahydroxanthenes by the reaction of dimedone and aromatic aldehydes in aqueous citric acid is described. In this green synthetic protocol promoted by the reaction media, the use of any other catalysts and hazardous organic solvents are avoided, making the work up procedure greener and easier. The isolation of the products, obtained in good yields, is readily performed by filtration and crystallization from ethanol when required and the aqueous acidic media can be easily recycled and reused several times without significant loss of catalytic activity.

En esta contribución se describe un procedimiento one-pot simple, conveniente y medioambientalmente amigable para la síntesis de 1,8-dioxo-octahidroxantenos por la reacción de dimedona y aldehídos aromáticos en ácido cítrico acuoso. En este protocolo de síntesis "verde" promovido por el medio de reacción, el uso de otros catalizadores y solventes orgánicos peligrosos es eliminado, haciendo el tratamiento final de la reacción más fácil y "verde". El aislamiento de los productos, obtenidos en buenos rendimientos, se lleva a cabo mediante filtración y recristalización en etanol cuando es necesario, y el medio acuoso ácido puede ser reciclado y reutilizado varias veces sin pérdida significativa de la actividad catalítica.

É descrito um procedimento simples, conveniente, e ambientalmente amigável para a síntese de 1,8-dioxo-octaidroxantenes pela reação de dimedona e aldeídos aromáticos em ácido cítrico aquoso em uma só etapa. Em este protocolo de síntese verde, promovido pelo meio de reação, a utilização de algum outro catalisador e solvente orgânico perigoso é evitada, fazendo o procedimento mais fácil e mais "verde". O isolamento dos produtos, obtidos em grande rendimento, é feito por meio de filtração e cristalização a partir de etanol quando é requerido e o meio aquoso ácido pode ser facilmente recuperado e reutilizado várias vezes sem perder significativamente sua atividade catalítica.

RESUMO

En este trabajo se reporta la síntesis de terpiridinas bajo la metodología de Kröhnke. Las terpiridinas obtenidas por este método, se analizaron por espectroscopia UV-Vis y de fluorescencia, y su respuesta a la presencia de varios metales en diferentes concentraciones fue evaluada para sistemas en solución acuosa. Los resultados muestran que la terpiridina TpyOH es altamente promisoria en la detección de mercurio bajo las condiciones experimentales reportadas.

This paper reports the synthesis of terpyridines using the Kröhnke methodology. The terpyridines obtained by this method were analyzed by UV-Vis spectroscopy and fluorescence, and its response to the presence of various metals at different concentrations was evaluated in aqueous systems. The results show that the terpyridine TpyOH is highly promising for the detection of mercury under the experimental conditions reported.

Este trabalho relata a síntese de terpyridines baixo a metodologia de Kröhnke. Os terpyridines obtidos por este método foram analisadas por espectroscopia UV- Vis e de fluorescência, e a sua resposta à presença de vários metais em diferentes concentrações foi avaliada em sistemas aquosos. Os resultados mostram que o terpyridine TpyOH é altamente promissor para a detecção de mercúrio sob as condições experimentais relatados.

RESUMO

En la búsqueda de una película polimérica con óptimas propiedades antiempañantes se seleccionó como matriz polimérica polietileno de baja densidad (LDPE), a la cual se incorporaron por extrusión uno de los siguientes aditivos: polisorbato 80, oleato de sorbitán, monooleato de glicerol y mezcla de glicéridos, cada uno a 3 concentraciones. Para evaluar la eficiencia antiempañante de los empaques se realizaron medidas de tensión superficial, ángulos de contacto, medidas de transmisión de luz y pruebas cualitativas de empañamiento en frío. Los resultados sugieren que la película con mejores propiedades antiempañantes es la que contiene oleato de sorbitán al 1%.

In search of a film with optimal antifogging properties, low density polyethylene (LDPE) was selected as polymeric matrix, and one of the following four additives were incorporated into the film by an extrusion process: polysorbate 80, sorbitan oleate, glycerol monooleate and glyceride mixture, each of them in 3 different concentrations. Measures of surface tension, light transmission, contact angles, and qualitative cold fogging test were made to assess the efficiency of fog resistant in all packages. The results suggest that the film with sorbitan oleate (1%) presents the best antifogging properties.

Na procura de uma película polimèrica com ótimas propriedades antiembaciamento, selecionou-se como matriz polimèrica polietileno de baixa densidade (LDPE) e, através de uma extrusão, incorporou-se um dos seguintes os aditivos polisorbarto 80, oleato de sorbitan, mono-oleato de glicerol e mistura de glicerídeos cada um em três concentrações diferentes. Para avaliar a eficiência antiembaciamento das películas se realizaram as medidas de tensão superficial, ângulos de contato, medidas de transmissão de luz e provas qualitativas de antiembaciamento em frio. Os resultados sugerem que a película que contèm o oleato de sorbitan 1% tem as melhores propriedades antiembaciamento.

RESUMO

En el presente trabajo se reporta la síntesis y caracterización optoelectrónica de tres sistemas fenilvinilideno con sustituyentes electrodonores tipo alcoxilo (-OR). Los sistemas fueron obtenidos por medio de la reacción de acoplamiento de Heck, con rendimientos superiores a 95%, una conjugación de configuración totalmente trans y con altos rendimientos cuánticos de fluorescencia de color verde-azul. La gran estereoselectividad de la metodología de síntesis utilizada se ve reflejada en la obtención de rendimientos cuánticos superiores a los reportados para sistemas fenilvinilideno de estructuras químicas similares, lo cual hace de estos sistemas fenilvinilideno estereoselectivos, materiales de alto atractivo comercial dentro de las nacientes tecnologías de la electrónica de polímeros.

In this paper, we report the synthesis and optoelectronic characterization of three phenylene vinylene systems with electron-donor substituents (alcoxide type, -OR). The systems were obtained by Heck cross-coupling reaction, with yields over 95%, pure trans configuration conjugation, and high fluorescent quantum yields of blue-green color. The high stereoselectivity of the synthesis used is shown by obtaining fluorescence quantum yields higher than similar phenylene vinylene systems reported in literature, which makes these systems very attractive materials for the emerging polymer electronic technology.

Neste trabalho, reporta-se a síntese e a ca-raterizaçâo optoeletrônica de très sistemas fenil vinilideno com substituintes eletrodoadores do tipo alcoxil (-OR). Os sistemas foram obtidos pela reacào de acoplamento de Heck, com rendimentos acima de 95%, com uma conjugacào de configuracào totalmente trans e com altos rendimentos quànticos de fluorescencia de cor verde-azul. A grande esteroseletividade da síntese utilizada se ve refletida na obtencào de rendimentos quànticos superiores aos reportados para os sistemas fenil vinilideno de estruturas químicas similares, o qual faz de estes sistemas fenil vinilideno materiais atraentes comercial-mente dentro das nascentes tecnologias da eletrònica de polímeros.