Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Sensors (Basel) ; 23(5)2023 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-36904726

RESUMO

The development of optical sensors for in situ testing has become of great interest in the rapid diagnostics industry. We report here the development of simple, low-cost optical nanosensors for the semi-quantitative detection or naked-eye detection of tyramine (a biogenic amine whose production is commonly associated with food spoilage) when coupled to Au(III)/tectomer films deposited on polylactic acid (PLA) supports. Tectomers are two-dimensional oligoglycine self-assemblies, whose terminal amino groups enable both the immobilization of Au(III) and its adhesion to PLA. Upon exposure to tyramine, a non-enzymatic redox reaction takes place in which Au(III) in the tectomer matrix is reduced by tyramine to gold nanoparticles, whose reddish-purple color depends on the tyramine concentration and can be identified by measuring the RGB coordinates (Red-Green-Blue coordinates) using a smartphone color recognition app. Moreover, a more accurate quantification of tyramine in the range from 0.048 to 10 µM could be performed by measuring the reflectance of the sensing layers and the absorbance of the characteristic 550 nm plasmon band of the gold nanoparticles. The relative standard deviation (RSD) of the method was 4.2% (n = 5) with a limit of detection (LOD) of 0.014 µM. A remarkable selectivity was achieved for tyramine detection in the presence of other biogenic amines, especially histamine. This methodology, based on the optical properties of Au(III)/tectomer hybrid coatings, is promising for its application in food quality control and smart food packaging.


Assuntos
Ouro , Nanopartículas Metálicas , Tiramina , Aminas Biogênicas , Poliésteres , Colorimetria/métodos
2.
Am J Primatol ; 85(4): e23469, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36710071

RESUMO

The population of West African chimpanzees (Pan troglodytes verus) is declining rapidly mostly due to the impact of human activities and habitat loss. Sierra Leone harbors the third largest population of this subspecies, recently reclassified as Critically Endangered in the 2016 IUCN Red List. Population monitoring provides crucial data for planning and evaluating conservation and management policies. Therefore, to assess the status of the population size inhabiting the Loma Mountains National Park (LMNP) in Sierra Leone, we performed a nest count survey and estimated chimpanzee density and abundance using distance sampling. In total, 34 × 2-km-line transects were surveyed, with transects being systematically distributed across the LMNP area (288.5 km2 ). Concurrently, we compiled environmental data, which were used to model nest distribution and infer the most relevant environmental and anthropogenic drivers of the observed nest abundances. We encountered 10.03 nests/km and estimated a density of 3.47 ± standard error (SE) 0.92 individuals/km2 (i.e., 1002 ± SE 266 individuals in total). Compared to the figures obtained from a systematic literature review, our results suggest that the density and abundance of chimpanzees in the LMNP is among the highest across Africa. Contrary to expectation, no specific anthropogenic features predicted nest distribution and abundance. However, the nest distribution model indicated preference for elevated and steep areas covered by closed evergreen forest, which could be an indication of human avoidance. Based on these results, we highlight the value of LMNP for the conservation of the chimpanzees in Sierra Leone and the urgent necessity of guarantying long-term funding for this park's management to ensure the survival of this critically endangered subspecies in West Africa.


Assuntos
Loma , Pan troglodytes , Humanos , Animais , Serra Leoa , Conservação dos Recursos Naturais/métodos , Parques Recreativos
3.
ACS Appl Mater Interfaces ; 14(47): 53228-53240, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36378993

RESUMO

A variety of two-dimensional (2D) nanomaterials, including graphene oxide and clays, are known to stabilize Pickering emulsions to fabricate structures for functions in sensors, catalysts, and encapsulation. We introduce here a novel Pickering emulsion using self-assembled amphiphilic triblock oligoglycine as the emulsifier. Peptide amphiphiles are more responsive to environmental changes (e.g., pH, temperature, and ionic strength) than inorganic 2D materials, which have a chemically rigid, in-plane structure. Noncovalent forces between the peptide molecules change with the environment, thereby imparting responsiveness. We provide new evidence that the biantennary oligoglycine, Gly4-NH-C10H20-NH-Gly4, self-assembles into 2D platelet structures, denoted as tectomers, in solution at a neutral buffered pH using small-angle X-ray scattering and molecular dynamics simulations. The molecules are stacked in the platelets with a linear conformation, rather than in a U-shape. We discovered that the lamellar oligoglycine platelets adsorbed at an oil/water interface and stabilized oil-in-water emulsions. This is the first report of 2D oligoglycine platelets being used as a Pickering stabilizer. The emulsions showed a strong pH response in an acidic environment. Thus, upon reducing the pH, the protonation of the terminal amino groups of the oligoglycine induced disassembly of the lamellar structure due to repulsive electrostatic forces, leading to emulsion destabilization. To demonstrate the application of the material, we show that a model active ingredient, ß-carotene, in the oil is released upon decreasing the pH. Interestingly, in pH 9 buffer, the morphology of the oil droplets evolved over time, as the oligoglycine stabilizer created progressively a thicker interfacial layer. This demonstration opens a new route to use self-assembled synthetic peptide amphiphiles to stabilize Pickering emulsions, which can be significant for biomedical and pharmaceutical applications.


Assuntos
Peptídeos , beta Caroteno , Emulsões/química , beta Caroteno/química , Eletricidade Estática , Concentração de Íons de Hidrogênio
4.
J Colloid Interface Sci ; 608(Pt 2): 2025-2038, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34749150

RESUMO

HYPOTHESIS: Surfactants in emulsions sometimes do not provide adequate stability against coalescence, whereas Pickering emulsions often offer greater stability. In a search for stabilizers offering biocompatibility, we hypothesized that carboxylated nanodiamonds (ND) would impart stability to Pickering emulsions. EXPERIMENTS: We successfully prepared Pickering emulsions of sunflower oil in water via two different methods: membrane emulsification and probe sonication. The first method was only possible when the pH of the aqueous ND suspension was ≤ 4. FINDINGS: Pendant-drop tensiometry confirmed that carboxylated ND is adsorbed at the oil/water interface, with a greater decrease in interfacial tension found with increasing ND concentrations in the aqueous phase. The carboxylated ND become more hydrophilic with increasing pH, according to three-phase contact angle analysis, because of deprotonation of the carboxylic acid groups. Membrane emulsification yielded larger (about 30 µm) oil droplets, probe sonication produced smaller (sub-µm) oil droplets. The Pickering emulsions show high stability against mechanical vibration and long-term storage for one year. They remain stable against coalescence across a wide range of pH values. Sonicated emulsions show stability against creaming. In this first-ever systematic study of carboxylated ND-stabilized Pickering emulsions, we demonstrate a promising application in the delivery of ß-carotene, as a model active ingredient.


Assuntos
Nanodiamantes , Ácidos Carboxílicos , Emulsões , Concentração de Íons de Hidrogênio , Tamanho da Partícula
5.
Am J Primatol ; 83(10): e23320, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34402081

RESUMO

Paleoclimate reconstructions have enhanced our understanding of how past climates have shaped present-day biodiversity. We hypothesize that the geographic extent of Pleistocene forest refugia and suitable habitat fluctuated significantly in time during the late Quaternary for chimpanzees (Pan troglodytes). Using bioclimatic variables representing monthly temperature and precipitation estimates, past human population density data, and an extensive database of georeferenced presence points, we built a model of changing habitat suitability for chimpanzees at fine spatio-temporal scales dating back to the Last Interglacial (120,000 BP). Our models cover a spatial resolution of 0.0467° (approximately 5.19 km2 grid cells) and a temporal resolution of between 1000 and 4000 years. Using our model, we mapped habitat stability over time using three approaches, comparing our modeled stability estimates to existing knowledge of Afrotropical refugia, as well as contemporary patterns of major keystone tropical food resources used by chimpanzees, figs (Moraceae), and palms (Arecacae). Results show habitat stability congruent with known glacial refugia across Africa, suggesting their extents may have been underestimated for chimpanzees, with potentially up to approximately 60,000 km2 of previously unrecognized glacial refugia. The refugia we highlight coincide with higher species richness for figs and palms. Our results provide spatio-temporally explicit insights into the role of refugia across the chimpanzee range, forming the empirical foundation for developing and testing hypotheses about behavioral, ecological, and genetic diversity with additional data. This methodology can be applied to other species and geographic areas when sufficient data are available.


Assuntos
Pan troglodytes , Refúgio de Vida Selvagem , Animais , Biodiversidade , Clima , Ecossistema , Variação Genética , Filogeografia
6.
J Chromatogr A ; 1638: 461895, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33477028

RESUMO

Identification of 19 molecular species of globotriaosylceramides (Gb3) in extracts from a Fabry's plasma patient and a healthy control was performed by High-Performance Thin-Layer Chromatography (HPTLC)-densitometry and online coupling to Mass Spectrometry (MS). Separation was carried out on LiChrospher plates using Automated Multiple Development (AMD). Densitometry was performed on twin plates by combining detection in the visible at 550 nm, through previous on-plate orcinol derivatization, and by Ultraviolet 190 nm, using a non-impregnated plate. The latter was directly coupled to an ion-trap mass spectrometer through an automated elution-based interface. Gb3 molecular species, which were identified by HPTLC- Electrospray Mass Spectrometry (+)-MS and confirmed by MS/MS or HPTLC-Atmospheric Pressure Chemical Ionization Mass Spectrometry (+)-MS, are: five isoforms of saturated Gb3; seven isoforms of methylated Gb3; and seven species with two additional double bonds. Twelve of these species were previously reported as biomarkers of Fabry's lysosomal disorder using a Liquid Chromatography-MS-based method, and the other seven are structurally similar, closely related to them. Saturated Gb3 isoforms migrated on LiChrospher plate in one of the separated peaks corresponding to the migration zone of ceramide trihexosides standard. Instead, methylated and unsaturated Gb3 species co-migrated with sphingomyelin species. Ion intensity ESI-MS profiles show that saturated Gb3 species in Fabry's plasma were in higher concentration than in control sample. Before applying the Thin-Layer Chromatography (TLC)-MS interface on HPTLC separated peaks, its positioning precision was first studied using ceramide tri-hexosides as model compound. This provided information on Gb3 peak broadening and splitting during its migration.


Assuntos
Cromatografia em Camada Fina/métodos , Densitometria , Doença de Fabry/sangue , Triexosilceramidas/sangue , Biomarcadores/sangue , Doença de Fabry/diagnóstico , Humanos , Metilação , Isoformas de Proteínas/sangue , Padrões de Referência , Espectrometria de Massas por Ionização por Electrospray , Esfingolipídeos/sangue , Espectrometria de Massas em Tandem , Triexosilceramidas/análise , Triexosilceramidas/química
7.
Am J Primatol ; 83(4): e23219, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33264434

RESUMO

Sierra Leone constitutes the western boundary to the West Africa Upper Guinea Rainforest, one of 35 global biodiversity hotspots. The country is home to the third-largest western chimpanzee (Pan troglodytes verus) population, a subspecies upgraded to Critically Endangered on the 2016 IUCN Red List. The main threats facing chimpanzees in Sierra Leone are habitat loss and increasing interactions with humans. The Mobonda Community Conservation Project (MCCP) is a component of Tacugama Chimpanzee Sanctuary's Community Outreach Program and Kids Environmental Education Program. The aim of MCCP is to promote community-based forest management in combination with wildlife conservation through carefully designed programs that benefit communities, wildlife, and ecologically significant habitats. MCCP also aims to promote self-sustained and integrated community landscape conservation, to facilitate policy discussions to strengthen wildlife laws, and to build the capacity of the Government to implement community-based wildlife and forestry protection projects. Since Tacugama began collecting data in Moyamba District in June 2015, the project has evolved into an assembly of components. MCCP currently works with five communities, running programs including environmental education, ecological research, biomonitoring including wildlife law enforcement, habitat rehabilitation through reforestation of identified wildlife corridors, improved sustainable livelihoods, and ecotourism initiatives. These programs contributed to a reduction in the threats facing wildlife in the area; the project has seen stable chimpanzee numbers where decrements to chimpanzee populations continue to be experienced elsewhere. Other MCCP outcomes include boosted sustainable agricultural production and higher oyster yields while decreasing the negative impact on the mangrove ecosystem allowing it to recover and support an array of important fauna and flora.


Assuntos
Ostreidae , Pan troglodytes , Animais , Conservação dos Recursos Naturais , Ecossistema , Serra Leoa
8.
Nanomaterials (Basel) ; 10(8)2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32824730

RESUMO

Carbon nanomaterials have attracted increasing attention in biomedicine recently to be used as drug nanocarriers suitable for medical treatments, due to their large surface area, high cellular internalization and preferential tumor accumulation, that enable these nanomaterials to transport chemotherapeutic agents preferentially to tumor sites, thereby reducing drug toxic side effects. However, there are widespread concerns on the inherent cytotoxicity of carbon nanomaterials, which remains controversial to this day, with studies demonstrating conflicting results. We investigated here in vitro toxicity of various carbon nanomaterials in human epithelial colorectal adenocarcinoma (Caco-2) cells and human breast adenocarcinoma (MCF-7) cells. Carbon nanohorns (CNH), carbon nanotubes (CNT), carbon nanoplatelets (CNP), graphene oxide (GO), reduced graphene oxide (GO) and nanodiamonds (ND) were systematically compared, using Pluronic F-127 dispersant. Cell viability after carbon nanomaterial treatment followed the order CNP < CNH < RGO < CNT < GO < ND, being the effect more pronounced on the more rapidly dividing Caco-2 cells. CNP produced remarkably high reactive oxygen species (ROS) levels. Furthermore, the potential of these materials as nanocarriers in the field of drug delivery of doxorubicin and camptothecin anticancer drugs was also compared. In all cases the carbon nanomaterial/drug complexes resulted in improved anticancer activity compared to that of the free drug, being the efficiency largely dependent of the carbon nanomaterial hydrophobicity and surface chemistry. These fundamental studies are of paramount importance as screening and risk-to-benefit assessment towards the development of smart carbon nanomaterial-based nanocarriers.

9.
PLoS One ; 14(5): e0215545, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31095574

RESUMO

Human population growth and anthropogenic activities are exacerbating pressures on biodiversity globally. Land conversion is aggravating habitat fragmentation and non-human primates are increasingly compelled to live in forest-agricultural mosaics. In Sierra Leone, more than half of the wild chimpanzee population (Pan troglodytes verus) occurs outside protected areas and competes for resources with farmers. Our study area, in the Moyamba district in south-western Sierra Leone, is practically devoid of forest and is dominated by cultivated and fallow fields, swamps and mangroves. In this region, traditional slash-and-burn agriculture modifies annually the landscape, sparing swamps and mangroves and semi-domesticated oil palms (Elaeis guineensis). This study aimed to explore ecological and anthropogenic factors influencing chimpanzee relative abundance across this highly degraded and human-impacted landscape. Between 2015 and 2016, we deployed 24 camera traps systematically across 27 1.25x1.25 km grid cells. Cameras were operational over a period of 8 months. We used binomial iCAR models to examine to what extent anthropogenic (roads, settlements, abandoned settlements and human presence) and habitat variables (swamps, farmland and mangroves) shape chimpanzee relative abundance. The best model explained 43.16% of the variation with distance to roads and swamps emerging as the best predictors of chimpanzee relative abundance. Our results suggest that chimpanzees avoid roads and prefer to maintain proximity to swamps. There was no significant effect of settlements, abandoned settlements, mangroves or human presence. It appears that chimpanzees do not avoid areas frequented by people; although, our findings suggest temporal avoidance between the two species. We highlight the importance of studying chimpanzee populations living in anthropogenic habitats like agricultural-swamp matrixes to better understand factors influencing their distribution and inform conservation planning outside protected areas.


Assuntos
Conservação dos Recursos Naturais/métodos , Pan troglodytes/crescimento & desenvolvimento , Animais , Fazendas , Atividades Humanas , Humanos , Crescimento Demográfico , Serra Leoa , Gravação em Vídeo , Áreas Alagadas
10.
Dev Psychobiol ; 61(6): 874-887, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30957221

RESUMO

More data are needed for a better understanding of the long-term influence of wider and combined stressful events in chimpanzee personality development. We evaluated the effects of bushmeat trade outcomes on the personality development in 84 African sanctuary chimpanzees. The chimpanzees presented different backgrounds regarding maternal care, social exposure, and abuse. We evaluated personality traits in chimpanzees using the Cattell 16PF personality questionnaire, the first application of this questionnaire in this species. We found that chimpanzees were rated as higher in anxiety after long social deprivation during infancy and juvenility, and if high human exposure was experienced. Mother-reared chimpanzees were rated as lower in restraint than hand-reared chimpanzees. Finally, mother-reared chimpanzees were rated as less dominant than hand-reared chimpanzees and rated higher when they had experienced severe mistreatment. Results suggest a wide range of possible stressful events could be potentially shaping rescued chimpanzees' personality and demonstrating the detrimental outcomes and consequences of the bushmeat and pet trade.


Assuntos
Ansiedade/fisiopatologia , Comportamento Animal/fisiologia , Inibição Psicológica , Pan troglodytes/fisiologia , Personalidade/fisiologia , Predomínio Social , Estresse Psicológico/fisiopatologia , Animais , Feminino , Masculino , Determinação da Personalidade
11.
J AOAC Int ; 101(6): 1993-2000, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29571302

RESUMO

High-performance thin-layer chromatography was directly combined with electrospray mass spectrometry (ESI-MS) for structural identification issues below the level of lipid classes in complex samples through a portable, automated, elution-based interface. For samples as diverse as biodiesel and human plasma, separation conditions using Automated Multiple Development were selected in each case to provide lipid classes as zones narrow enough to ensure a direct transfer of them to ESI-MS. The respective zone of interest can be selected at will. ESI+ spectra of neutral lipids and sphingolipids showed sodium adducts when recorded from the plate. By using the described technique and ion-trap technology, the respective sodium adducts were fragmented. Sodium remained as the charge of the fragment ions and, thus, was useful for their structural identification through MSn. In this way, composition profiles of each class by ESI+-MS, and further identification of individual lipids and the molecular species belonging to each of them, were obtained by MS/MS and/or high-resolution MS. Thus, mono and diacylglycerides in ESI+ and fatty acids (in ESI-) were identified as low-concentration impurities in a fatty acid methyl ester-based biodiesel sample. Likewise, molecular species of sphingomyelins and globotriaosylceramides were unequivocally identified in human plasma samples.


Assuntos
Cromatografia em Camada Fina/métodos , Diglicerídeos/análise , Monoglicerídeos/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Esfingomielinas/sangue , Biocombustíveis/análise , Análise Química do Sangue/métodos , Misturas Complexas/química , Ácidos Graxos/análise , Humanos , Sódio/química , Espectrometria de Massas em Tandem
12.
Am J Primatol ; 79(9)2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28671714

RESUMO

Elevated Lipoprotein(a) (Lp(a)) plasma concentrations are a risk factor for cardiovascular disease in humans, largely controlled by the LPA gene encoding apolipoprotein(a) (apo(a)). Lp(a) is composed of low-density lipoprotein (LDL) and apo(a) and restricted to Catarrhini. A variable number of kringle IV (KIV) domains in LPA lead to a size polymorphism of apo(a) that is inversely correlated with Lp(a) concentrations. Smaller apo(a) isoforms and higher Lp(a) levels in central chimpanzees (Pan troglodytes troglodytes [PTT]) compared to humans from Europe had been reported. We studied apo(a) isoforms and Lp(a) concentrations in 75 western (Pan troglodytes verus [PTV]) and 112 central chimpanzees, and 12 bonobos (Pan paniscus [PPA]), all wild born and living in sanctuaries in Sierra Leone, Republic of the Congo, and DR Congo, respectively, and 116 humans from Gabon. Lp(a) levels were severalfold higher in western than in central chimpanzees (181.0 ± 6.7 mg/dl vs. 56.5 ± 4.3 mg/dl), whereas bonobos showed intermediate levels (134.8 ± 33.4 mg/dl). Apo(a) isoform sizes differed significantly between subspecies (means 20.9 ± 2.2, 22.9 ± 4.4, and 23.8 ± 3.8 KIV repeats in PTV, PTT, and PPA, respectively). However, far higher isoform-associated Lp(a) concentrations for all isoform sizes in western chimpanzees offered the main explanation for the higher overall Lp(a) levels in this subspecies. Human Lp(a) concentrations (mean 47.9 ± 2.8 mg/dl) were similar to those in central chimpanzees despite larger isoforms (mean 27.1 ± 4.9 KIV). Lp(a) and LDL, apoB-100, and total cholesterol levels only correlated in PTV. This remarkable differentiation between chimpanzees from different African habitats and the trait's similarity in humans and chimpanzees from Central Africa poses the question of a possible impact of an environmental factor that has shaped the genetic architecture of LPA. Overall, studies on the cholesterol-containing particles of Lp(a) and LDL in chimpanzees should consider differentiation between subspecies.


Assuntos
Apoproteína(a)/genética , Lipoproteína(a)/genética , Pan troglodytes/genética , África Central , Animais , Congo , Gabão , Humanos , Serra Leoa
13.
Nanoscale ; 9(23): 7791-7804, 2017 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-28186213

RESUMO

Here we present a route for non-covalent functionalization of carboxylated multi-walled carbon nanotubes and graphene oxide with novel two-dimensional peptide assemblies. We show that self-assembled amino-terminated biantennary and tetraantennary oligoglycine peptides (referred to as tectomers) effectively coat carboxylated multi-walled carbon nanotubes and also strongly interact with graphene oxide due to electrostatic interactions and hydrogen bonding as the driving force, respectively. The resulting hybrids can be made into free-standing conducting composites or applied in the form of thin, pH-switchable bioadhesive coatings onto graphene oxide fibers. Monitoring of cell viability of pancreatic cell lines, seeded on those CNT hybrids, show that they can be used as two- and three-dimensional scaffolds to tissue engineer tumour models for studying ex vivo the tumour development and response to treatment. This highly versatile method in producing pH-responsive hybrids and coatings offers an attractive platform for a variety of biomedical applications and for the development of functional materials such as smart textiles, sensors and bioelectronic devices.

14.
ACS Appl Mater Interfaces ; 8(3): 1913-21, 2016 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-26730704

RESUMO

The nanocarrier capabilities of atomically smooth two-dimensional sheets of a biantennary oligoglycine peptide C8H16(-CH2-NH-Gly5)2 (also called tectomers) are demonstrated. We show that the pH-controlled, rapid, and reversible assembly and disassembly of oligoglycine can be effectively used for controlled loading and release of the anticancer drug and fluorescent probe coralyne. The calculated partition coefficient in water is of the same order of magnitude or higher when compared to other nanocarriers such as liposomes and micelles, signifying the tectomer's impressive loading capabilities. Moreover, the loading of guest molecules in tectomers facilitates the protection from rapid photochemically induced degradation. Such efficient, pH-sensitive, stable, and biocompatible nanocarriers are extremely attractive for biosensing, therapeutic, and theranostic applications. Additionally, our results suggest that these planar self-assembled materials can also act as phase-transfer vehicles for hydrophobic cargoes further broadening their biomedical and technological applications.


Assuntos
Portadores de Fármacos/química , Nanopartículas/química , Peptídeos/química , Alcaloides de Berberina/farmacologia , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Microscopia Confocal , Nanopartículas/ultraestrutura , Solubilidade , Soluções , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , beta Caroteno/farmacologia
15.
Talanta ; 148: 393-400, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26653465

RESUMO

A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO.

16.
Rev. cienc. med. Pinar Rio ; 17(5): 196-206, sep.-oct. 2013.
Artigo em Espanhol | LILACS | ID: lil-739973

RESUMO

Introducción: los tumores cardíacos primarios son aquellos que se originan en Miocardio o Pericardio. El 90% son benignos, no son invasivos, pero debido a su localización pueden provocar alteraciones hemodinámicas graves y arrítmias. Presentación del caso: dos casos portadores de tumores cardíacos diagnosticados en la etapa prenatal, una gestante de 32 años, portadora de una Neurofribromatosis que en la ecocardiografía fetal de su hijo, se identifican dos tipos de tumores cardíacos, un mixoma auricular y un fibroma, y un niño que desde la etapa prenatal se diagnosticó un rabdomioma, lo cual se confirmó al nacimiento y que regresó espontáneamente. Conclusiones: a ecocardiografía fetal permite cada vez con más frecuencia, el diagnóstico intraútero de tumores cardíacos. Los rabdomiomas regresan en más del 50% de los casos, pero pueden ser un marcador de Esclerosis Tuberosa. Los tumores cardiacos se asocian a otras afecciones congénitas y requieren de tratamiento quirúrgico. Aspectos todos a tener en consideración para realizar el asesoramiento genético a la familia.


Introduction: primary cardiac tumors are those having their origin in the myocardium or pericardium. The 90% are benign, not invasive, but due to their location they can cause severe hemodynamic alterations and arrhythmias. Case report: two patients, carriers of cardiac tumors that were diagnosed in prenatal stages, a 32 year-old pregnant woman, carrier of a Neurofibromatosis, in the fetal echography of her child, two types of cardiac tumors were identified: an atrial myxoma and a fibroma, along with a fetus who presented a rhabdomyoma that was diagnosed during the prenatal stage and confirmed at birth having a spontaneous remission. Conclusions: more frequently fetal echocardiography makes possible the intrauterine diagnosis of cardiac tumors. Rhabdomyomas have a spontaneous remission in more than 50% of the cases, but they can be a marker of Tuberous Sclerosis. Cardiac tumors are associated with other congenital affections and require surgical treatment. All these aspects must be considered to accomplish genetic counseling to the family.

17.
Rev cienc méd pinar río ; 17(5)oct. 2013. ilus
Artigo em Espanhol | CUMED | ID: cum-55980

RESUMO

Los tumores cardíacos primarios son aquellos que se originan en Miocardio o Pericardio. El 90 por ciento son benignos, no son invasivos, pero debido a su localización pueden provocar alteraciones hemodinámicas graves y arrítmias. Dos casos portadores de tumores cardíacos diagnosticados en la etapa prenatal, una gestante de 32 años, portadora de una Neurofribromatosis que en la ecocardiografía fetal de su hijo, se identifican dos tipos de tumores cardíacos, un mixoma auricular y un fibroma, y un niño que desde la etapa prenatal se diagnosticó un rabdomioma, lo cual se confirmó al nacimiento y que regresó espontáneamente. A ecocardiografía fetal permite cada vez con más frecuencia, el diagnóstico intraútero de tumores cardíacos. Los rabdomiomas regresan en más del 50% de los casos, pero pueden ser un marcador de Esclerosis Tuberosa. Los tumores cardiacos se asocian a otras afecciones congénitas y requieren de tratamiento quirúrgico. Aspectos todos a tener en consideración para realizar el asesoramiento genético a la familia(AU)


Primary cardiac tumors are those having their origin in the myocardium or pericardium. 90 per cent are benign, not invasive, but due to their location they can cause severe hemodynamic alterations and arrhythmias. Two patients, carriers of cardiac tumors that were diagnosed in prenatal stages, a 32 year-old pregnant woman, carrier of a Neurofibromatosis, in the fetal echography of her child, two types of cardiac tumors were identified: an atrial myxoma and a fibroma, along with a fetus who presented a rhabdomyoma that was diagnosed during the prenatal stage and confirmed at birth having a spontaneous remission. More frequently fetal echocardiography makes possible the intrauterine diagnosis of cardiac tumors. Rhabdomyomas have a spontaneous remission in more than 50% of the cases, but they can be a marker of Tuberous Sclerosis. Cardiac tumors are associated with other congenital affections and require surgical treatment. All these aspects must be considered to accomplish genetic counseling to the family(AU)


Assuntos
Humanos , Gravidez , Miocárdio , Neoplasias , Aconselhamento Genético , Ecocardiografia , Feto
18.
BMC Microbiol ; 13: 204, 2013 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-24025115

RESUMO

BACKGROUND: It is increasingly recognized that the bacteria that live in and on the human body (the microbiome) can play an important role in health and disease. The composition of the microbiome is potentially influenced by both internal factors (such as phylogeny and host physiology) and external factors (such as diet and local environment), and interspecific comparisons can aid in understanding the importance of these factors. RESULTS: To gain insights into the relative importance of these factors on saliva microbiome diversity, we here analyze the saliva microbiomes of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) from two sanctuaries in Africa, and from human workers at each sanctuary. The saliva microbiomes of the two Pan species are more similar to one another, and the saliva microbiomes of the two human groups are more similar to one another, than are the saliva microbiomes of human workers and apes from the same sanctuary. We also looked for the existence of a core microbiome and find no evidence for a taxon-based core saliva microbiome for Homo or Pan. In addition, we studied the saliva microbiome from apes from the Leipzig Zoo, and found an extraordinary diversity in the zoo ape saliva microbiomes that is not found in the saliva microbiomes of the sanctuary animals. CONCLUSIONS: The greater similarity of the saliva microbiomes of the two Pan species to one another, and of the two human groups to one another, are in accordance with both the phylogenetic relationships of the hosts as well as with host physiology. Moreover, the results from the zoo animals suggest that novel environments can have a large impact on the microbiome, and that microbiome analyses based on captive animals should be viewed with caution as they may not reflect the microbiome of animals in the wild.


Assuntos
Microbiota , Pan paniscus/microbiologia , Pan troglodytes/microbiologia , Saliva/microbiologia , Adulto , África , Animais , Alemanha , Humanos , Adulto Jovem
19.
J Phys Chem B ; 117(25): 7593-604, 2013 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-23745842

RESUMO

We investigated the abilities of a family of tau-protein-related amphiphilic peptides with predictable self-association characteristics (N-acetyl-VQIVXK-NH2 (X = F, L, V, W, Y, A, K)) to disperse single-walled carbon nanotubes (SWCNTs). The dispersion abilities of these peptides could be explained by a linear combination of their hydrophobic and amyloidogenic properties in a 60/40 ratio. Circular dichroism (CD) spectra of one of the peptides having a high propensity to form an amyloid (N-acetyl-VQIVYK-NH2 (AcPHF6)) showed that this peptide exists as a random coil in water but assumes a ß-sheet conformation when sonicated with SWCNTs. Electron microscopy results, changes in near-infrared spectra, and changes in the Raman spectra upon formation of composites suggest that AcPHF6 intercalates, coats, and exfoliates SWCNT bundles. N-terminal truncation of AcPHF6 greatly reduced its ability to disperse SWCNTs. Taken together, our results suggest that amyloidogenic peptides wrap SWCNTs, forming an extensive ß-sheet network. To date, peptides based on the AcVQIVXK framework are structurally the simplest peptides that have been found to disperse CNTs, and an understanding of those properties that determine their efficiency may be used to design even more efficient peptides for these purposes. We believe that due to the structural simplicity, this family of peptides will have clear synthetic advantages over peptides now known to disperse CNTs.


Assuntos
Nanotubos de Carbono/química , Peptídeos/química , Proteínas tau/química , Sequência de Aminoácidos , Amiloide/química , Amiloide/metabolismo , Dicroísmo Circular , Interações Hidrofóbicas e Hidrofílicas , Peptídeos/metabolismo , Estrutura Secundária de Proteína
20.
Nanoscale Res Lett ; 8(1): 233, 2013 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-23679938

RESUMO

Laser ablation of selected coordination complexes can lead to the production of metal-carbon hybrid materials, whose composition and structure can be tailored by suitably choosing the chemical composition of the irradiated targets. This 'laser chemistry' approach, initially applied by our group to the synthesis of P-containing nanostructured carbon foams (NCFs) from triphenylphosphine-based Au and Cu compounds, is broadened in this study to the production of other metal-NCFs and P-free NCFs. Thus, our results show that P-free coordination compounds and commercial organic precursors can act as efficient carbon source for the growth of NCFs. Physicochemical characterization reveals that NCFs are low-density mesoporous materials with relatively low specific surface areas and thermally stable in air up to around 600°C. Moreover, NCFs disperse well in a variety of solvents and can be successfully chemically processed to enable their handling and provide NCF-containing biocomposite fibers by a wet-chemical spinning process. These promising results may open new and interesting avenues toward the use of NCFs for technological applications.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...