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1.
Democratization ; 31(6): 1125-1139, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39193066

RESUMEN

This paper examines the importance of, and variations in, political alignment within African regimes. Political alignment is how leaders establish sufficient political support across elites: we posit that formal appointments are the primary way that leaders manipulate political coalitions in order to secure their collective authority and tenure. Appointments, individually and collectively, can take on multiple characteristics: they can create inclusive or exclusive coalitions, transactional or loyal support, volatile or stable elite networks. Appointment powers have greater salience since governments institutionalized and formalized in governance systems across democratic and autocratic states. Manipulating who holds and secures power at the subnational and national levels, rather than repressive control or state capacity, underpins the stability, security, and survival of modern African regimes.

2.
J Hazard Mater ; 465: 133093, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38056254

RESUMEN

Nuclear facilities continue to be developed to help meet global energy demands while reducing fossil fuel use. However, an incident during the dismantling of these facilities could accidentally release tritiated particles (e.g. stainless steel) into the environment. Herein, we investigated the environmental dosimetry, fate, and impact of tritiated stainless steel (nano)particles (1 mg.L-1 particles and 1 MBq.L-1 tritium) using indoor freshwater aquatic mesocosms to mimic a pond ecosystem. The tritium (bio)distribution and particle fate and (bio)transformation were monitored in the different environmental compartments over 4 weeks using beta counting and chemical analysis. Impacts on picoplanktonic and picobenthic communities, and the benthic freshwater snail, Anisus vortex, were assessed as indicators of environmental health. Following contamination, some tritium (∼16%) desorbed into the water column while the particles rapidly settled onto the sediment. After 4 weeks, the particles and the majority of the tritium (>80%) had accumulated in the sediment, indicating a high exposure of the benthic ecological niche. Indeed, the benthic grazers presented significant behavioral changes despite low steel uptake (<0.01%). These results provide knowledge on the potential environmental impacts of incidental tritiated (nano)particles, which will allow for improved hazard and risk management.


Asunto(s)
Ecosistema , Acero Inoxidable , Tritio , Agua Dulce , Ambiente
3.
Cancers (Basel) ; 15(20)2023 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-37894311

RESUMEN

Carboranes have emerged as one of the most promising boron agents in boron neutron capture therapy (BNCT). In this context, in vivo studies are particularly relevant, since they provide qualitative and quantitative information about the biodistribution of these molecules, which is of the utmost importance to determine the efficacy of BNCT, defining their localization and (bio)accumulation, as well as their pharmacokinetics and pharmacodynamics. First, we gathered a detailed list of the carboranes used for in vivo studies, considering the synthesis of carborane derivatives or the use of delivery system such as liposomes, micelles and nanoparticles. Then, the formulation employed and the cancer model used in each of these studies were identified. Finally, we examined the analytical aspects concerning carborane detection, identifying the main methodologies applied in the literature for ex vivo and in vivo analysis. The present work aims to identify the current strengths and weakness of the use of carboranes in BNCT, establishing the bottlenecks and the best strategies for future applications.

4.
Front Digit Health ; 4: 934609, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36860207

RESUMEN

Privacy by design within a system for assisted living, personalised care, and wellbeing is crucial to protect users from misuse of the data collected about their health. Especially if the information is collected through audio-video devices, the question is even more delicate due to the nature of these data. In addition to guaranteeing a high level of privacy, it is necessary to reassure end users about the correct use of these streams. The evolution of data analysis techniques began to take on an important role and increasingly defined characteristics in recent years. The purpose of this paper is twofold: on the one hand, it presents a state of the art about privacy in European Active Healthy Ageing/Active Healthy Ageing projects, with a focus on those related to audio and video processing. On the other hand, it proposes a methodology, developed in the context of the European project PlatfromUptake.eu, to identify clusters of stakeholders and application dimensions (technical, contextual, and business), define their characteristics, and show how privacy constraints affect them. From this study, we then generated a Strengths, Weaknesses, Opportunities, and Threats analysis in which we aim to identify the critical features connected to the selection and involvement of relevant stakeholders for the success of a project. Applying this type of methodology to the initial stages of a project allows understanding of which privacy issues could be related to the various stakeholder groups and which problems can then affect the correct development of the project. The idea is, therefore, to suggest a privacy-by-design approach according to the categories of stakeholders and project dimensions. The analysis will cover technical aspects, legislative and policies-related aspects also regarding the point of view of the municipalities, and aspects related to the acceptance and, therefore, to the perception of the safety of these technologies by the final end users.

5.
Environ Sci Technol ; 55(24): 16270-16282, 2021 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-34854667

RESUMEN

In the past decade, mesocosms have emerged as a useful tool for the environmental study of engineered nanomaterials (ENMs) as they can mimic the relevant exposure scenario of contamination. Herein, we analyzed the scientific outcomes of aquatic mesocosm experiments, with regard to their designs, the ENMs tested, and the end points investigated. Several mesocosm designs were consistently applied in the past decade to virtually mimic various contamination scenarios with regard to ecosystem setting as well as ENMs class, dose, and dosing. Statistical analyses were carried out with the literature data to identify the main parameters driving ENM distribution in the mesocosms and the potential risk posed to benthic and planktonic communities as well as global ecosystem responses. These analyses showed that at the end of the exposure, mesocosm size (water volume), experiment duration, and location indoor/outdoor had major roles in defining the ENMs/metal partitioning. Moreover, a higher exposure of the benthic communities is often observed but did not necessarily translate to a higher risk due to the lower hazard posed by transformed ENMs in the sediments (e.g., aggregated, sulfidized). However, planktonic organisms were generally exposed to lower concentrations of potentially more reactive and toxic ENM species. Hence, mesocosms can be complementary tools to existing standard operational procedures for regulatory purposes and environmental fate and risk assessment of ENMs. To date, the research was markedly unbalanced toward the investigation of metal-based ENMs compared to metalloid- and carbon-based ENMs but also nanoenabled products. Future studies are expected to fill this gap, with special regard to high production volume and potentially hazardous ENMs. Finally, to take full advantage of mesocosms, future studies must be carefully planned to incorporate interdisciplinary approaches and ensure that the large data sets produced are fully exploited.


Asunto(s)
Ecosistema , Nanoestructuras , Nanoestructuras/toxicidad , Medición de Riesgo
6.
J Craniofac Surg ; 31(6): 1681-1686, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32657976

RESUMEN

PURPOSE: The aim of the present paper is to verify the long-term results in dental and skeletal stability in terms of symmetry, occlusion and functional balance by the association between the IS and the SF technique. METHODS: In this paper, the authors described 12 cases of severe class III malocclusion treated by the association between the IS and the SF technique. RESULTS: At 1 year of post-orthodontic follow up, the patients present an Angle class I occlusal relationship, no deep bite, no scissor or cross-bite and no open bite. No one patient referred TMJ discomfort nor severe post-surgical complications and no surgical-orthodontic relapse occurred. The surgical and occlusal results are stable in terms of stability in all patients. CONCLUSION: The results of this study suggest the validity of our protocol in management of class III malocclusion patients.


Asunto(s)
Aparatos Ortodóncicos Removibles , Adulto , Cefalometría/métodos , Oclusión Dental , Femenino , Humanos , Masculino , Maloclusión , Maloclusión de Angle Clase III , Mordida Abierta , Adulto Joven
7.
Int J Low Extrem Wounds ; 19(1): 78-85, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31679415

RESUMEN

The closure of wounds associated with soft tissue defects is surgically challenging, frequently requiring extensive plastic surgery and free flaps. The combination of ADM and STSG is an innovative method used to cover such wounds. The human-derived ADMs (H-ADMs) are the most described in the literature but according to European legislations, Companies H-ADMs outside the EC are not allowed to commercialize them in Europe, H-ADMs being "human products" and not "medical devices", so being ruled by European legislations on transplants. The Skin Bank of the Bufalini Hospital (Cesena, Italy) obtained in 2009 the approval for the production and distribution of the first human cadaver-donor derived ADM from the Italian National Transplant Center and National Health Institute, we called with the Italian acronym M.O.D.A. (Matrice Omologa Dermica Acellulata). We present here the first use of a new H-ADM for treatment of distal lower extremity wounds with exposed tendons managed in one-stage pocedure with STSG. The excellent performance suggests that in cases where autologous tissue is unavailable or undesirable, the use of M.O.D.A. in one-stage procedure represents a promising alternative for covering wounds associated with tendons exposition.


Asunto(s)
Dermis Acelular , Traumatismos del Tobillo/cirugía , Procedimientos de Cirugía Plástica/métodos , Trasplante de Piel/métodos , Traumatismos de los Tejidos Blandos/cirugía , Trasplante Heterólogo/métodos , Técnicas de Cierre de Heridas , Adulto , Femenino , Humanos , Italia , Evaluación de Procesos y Resultados en Atención de Salud , Recuperación de la Función , Tendones , Cicatrización de Heridas
8.
Front Plant Sci ; 10: 962, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31428109

RESUMEN

The common bean is one of the most important staples in many areas of the world. Extensive phenotypic and genetic characterization of unexplored bean germplasm are still needed to unlock the breeding potential of this crop. Dissecting genetic control of flowering time is of pivotal importance to foster common bean breeding and to develop new varieties able to adapt to changing climatic conditions. Indeed, flowering time strongly affects yield and plant adaptation ability. The aim of this study was to investigate the genetic control of days to flowering using a whole genome association approach on a panel of 192 highly homozygous common bean genotypes purposely developed from landraces using Single Seed Descent. The phenotypic characterization was carried out at two experimental sites throughout two growing seasons, using a randomized partially replicated experimental design. The same plant material was genotyped using double digest Restriction-site Associated DNA sequencing producing, after a strict quality control, a dataset of about 50 k Single Nucleotide Polymorphisms (SNPs). The Genome-Wide Association Study revealed significant and meaningful associations between days to flowering and several SNP markers; seven genes are proposed as the best candidates to explain the detected associations.

9.
J Craniofac Surg ; 30(8): e784-e787, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31348202

RESUMEN

PURPOSE: The aim of the authors study is to demonstrate the soft tissues changes in the eyelid-brow area (ELBA) in patients with long-face syndrome after LeFort I osteotomy and impaction movements. MATERIALS AND METHODS: To perform this study the authors have analyzed retrospectively orthognathic patients with at least 1 years of completely follow-up. The inclusion criteria were: long-face syndrome according to Farkas' studies and vertical maxillary shortening movement without considering whether movements have been made in the other 2 planes of space (sagittal and horizontal).Orthognathic patients in which the maxillary impaction movement did not correlate to the long-face syndrome represented the control group. In this group too the authors did not consider if other movements were performed.Size and shape of the eyelid and the eyebrow was assessed on the frontal patients photos calibrated on the three-dimensional soft tissue volume imported from cone beam computed tomography.Two reference lines were taken: a horizontal line from the nasal point passing through both medial canthal angles and a perpendicular line through the pupil centre bilaterally. Then the measures were taken.The same operator (A.C.) took all of the measurements.In both groups, the preoperative measures were then compared with the postoperative ones. Then the soft tissue changes in both groups were compared. RESULTS: The results demonstrate different reaction of the ELBA after orthognathic surgery. The ELBA's position changes in long-face patients in a higher position after maxillary impaction. The authors did not obtain the same results in patients who do not have long-face syndrome. CONCLUSIONS: Repositioning skeletal bases in patients with long face causes a change in the ELBA's morphology.


Asunto(s)
Párpados/cirugía , Anomalías Maxilomandibulares/cirugía , Adolescente , Adulto , Tomografía Computarizada de Haz Cónico , Párpados/diagnóstico por imagen , Femenino , Humanos , Imagenología Tridimensional/métodos , Anomalías Maxilomandibulares/diagnóstico por imagen , Masculino , Maxilar/cirugía , Procedimientos Quirúrgicos Ortognáticos/métodos , Estudios Retrospectivos , Diente Impactado , Adulto Joven
10.
Cell Tissue Bank ; 20(2): 183-192, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30767153

RESUMEN

Full-thickness skin wounds occur in many different clinical cases and the use of biological acellular dermal matrices (ADMs) to reconstruct the damaged area is increasing in the field of plastic and reconstructive surgery. In particular, the ability of ADMs to maintain the structural properties of extracellular matrix as well as to provide a suitable environment for cell growth makes their use suitable for the improvement of wound healing and the reduction of side effects deriving from contracture and scar tissue formation. In this study, we describe the clinical use of a recently developed human dermal matrix (HDM) in combination with graft skin as an alternative reconstructive solution for the treatment of full-thickness skin wounds. The HDM was applied in combination with autologous graft skin on three different clinical cases in which full-thickness skin wounds occurred. The clinical outcomes were evaluated in the patients during their follow-up. Histological as well as ultra-structural analysis were also performed on skin biopsy of the clinical case 3 one year after the treatment with HDM. The use of HDM stimulates the wound healing process in all clinical cases of full-thickness skin wounds here described with a functional and aesthetic rescue of the damaged area. Histological and ultra-structural analysis show a regenerative healing of the wound area with well-organized/oriented connective tissue in which cellular infiltration as well as blood vessels are evident. Our results support the clinical use of HDM as a permanent dermal replacement for the treatment of full-thickness skin wounds.


Asunto(s)
Dermis Acelular , Matriz Extracelular/fisiología , Trasplante de Piel/métodos , Piel/lesiones , Humanos , Piel Artificial , Cicatrización de Heridas/fisiología
11.
J Craniofac Surg ; 30(3): 793-797, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30418285

RESUMEN

Temporomandibular disorders (TMD) are common disorders that usually involve temporomandibular joint (TMJ), masticatory muscles, and other relevant structures. The symptoms may vary limiting the patients' quality of life. Many treatment options were proposed during the last years with the aim to treat the pathology. In this article, we analyze the effect of the injection of the fat-derived stem cell in the joint as a new treatment option.


Asunto(s)
Tejido Adiposo/citología , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/citología , Trastornos de la Articulación Temporomandibular/terapia , Humanos , Calidad de Vida
12.
Phytochemistry ; 144: 9-18, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28863306

RESUMEN

Silymarin is the phytochemical with medicinal properties extracted from Silybum marianum (L.) Gaertn. fruits. Yet, little information is available about silymarin biosynthesis. Moreover, the generally accepted pathway, formulated thus far, is not in agreement with actual experimental measurements on flavonolignan contents. The present work analyses flavonolignan and taxifolin content in 201 S. marianum samples taking into consideration a wide phenotypic variability. Two stable chemotypes were identified: one characterized by both high silychristin and silybin content (chemotype A) and another by a high silydianin content (chemotype B). Through the correlation analysis of samples divided according to chemotype, it was possible to construct a simplified silymarin biosynthetic pathway that is sufficiently versatile in explaining experimental results responding to the actually unresolved questions about this process. The proposed pathway highlights that three separate and equally sized metabolite pools exist, namely: diastereoisomers A (silybin A plus isosilybin A), diastereoisomers B (silybin B plus isosilybin B) and silychristin. In both A and B diastereoisomers pools, isosilybin A and isosilybin B always represent a given amount of the metabolite flux through the specific metabolite pool suggesting the possible involvement of dirigent protein-like enzymes. We suggest that chemotype B possesses a complete silymarin biosynthetic pathway in which silydianin biosynthesis is enzymatically controlled. On the contrary, chemotype A is probably a natural mutant unable to biosynthesize silydianin. The present simplified pathway for silymarin biosynthesis will constitute an important tool for the further understanding of the reactions that drive flavonolignan biosynthesis in S. marianum.


Asunto(s)
Flavonolignanos/metabolismo , Frutas/química , Silybum marianum/química , Silimarina/biosíntesis , Flavonolignanos/análisis , Frutas/metabolismo , Silybum marianum/metabolismo , Conformación Molecular , Silimarina/química , Estereoisomerismo
13.
Chemosphere ; 175: 1-7, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28211322

RESUMEN

Carbon-based nanomaterials, such as C60 fullerenes, are expected to accumulate in soil due to direct release and deposition from the atmosphere. However, little is known about the environmental fate of these nanoparticles which may be susceptible to photochemical and microbial degradation. In the present work, C60 was incubated for a period of 28 days and irradiated with UVA light. Three experiments were carried out where the fullerenes were either spiked onto a glass surface or added to quartz sand or sandy soil samples. At specific time intervals the samples were extracted and analysed by liquid chromatography coupled to UV or high resolution mass spectrometric (HRMS) detection. The fullerenes were degraded in all the treatments and the decay followed a pseudo-first-order rate law. In absence of a solid matrix, the half-life (t1/2) of the C60 was 13.1 days, with an overall degradation of 45.1% that was accompanied by the formation of functionalized C60-like structures. Furthermore, mass spectrometric analysis highlighted the presence of a large number of transformation products that were not directly related to the irradiation and presented opened cage and oxidized structures. When C60 was spiked into solid matrices the degradation occurred at a faster rate (t1/2 of 4.5 and 0.8 days for quartz sand and sandy soil, respectively). Minor but consistent losses were found in the non-irradiated samples, presumably due to biotic or chemical processes occurring in these samples. The results of this study suggest that light-mediated transformation of the fullerenes will occur in the environment.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Fulerenos/química , Fulerenos/efectos de la radiación , Contaminantes del Suelo/efectos de la radiación , Suelo , Rayos Ultravioleta , Cromatografía Liquida , Semivida , Espectrometría de Masas , Modelos Químicos , Nanoestructuras/química , Fotoquímica , Suelo/química
14.
Sci Total Environ ; 576: 273-283, 2017 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-27788442

RESUMEN

Only very limited information is available on measured environmental concentrations of nanoparticles. In this study, several environmental compartments in The Netherlands were probed for the presence of nanoparticles. Different types of water were screened for the presence of inorganic (Ag, Au, TiO2) and organic nanoparticles (C60, C70, [6,6]-phenyl-C61-butyric acid octyl ester, [6,6]-phenyl-C61-butyric acid butyl ester, [6,6]-phenyl-C61-butyric acid methyl ester, [6,6]-bis-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C71-butyric acid methyl ester, [6,6]-thienyl-C61-butyric acid methyl ester). Air samples were analysed for the presence of nanoparticulate Mo, Ag, Ce, W, Pd, Pt, Rh, Zn, Ti, Si, B as well as Fe and Cu. ICP-MS, Orbitrap-HRMS, SEM and EDX were used for this survey. Water samples included dune and bank filtrates, surface waters and ground waters as well as influents, effluents and sludge of sewage treatment plants (STPs), and surface waters collected near airports and harbours. Air samples included both urban and rural samples. C60 was detected in air, sewage treatment plants, influents, effluents and sludge, but in no other aqueous samples despite the low detection limit of 0.1ng/L. C70 and functionalised fullerenes were not detected at all. In STP sludge and influent the occurrence of Ag and Au nanoparticles was verified by SEM/EDX and ICP-MS. In air up to about 25m% of certain metals was found in the nanosize fraction. Overall, between 1 and 6% of the total mass from metals in the air samples was found in the size fraction <100nm.


Asunto(s)
Nanopartículas/análisis , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente , Fulerenos/análisis , Países Bajos , Aguas del Alcantarillado , Agua
15.
Environ Pollut ; 219: 47-55, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27661727

RESUMEN

Fullerenes are carbon based nanoparticles that may enter the environment as a consequence of both natural processes and human activities. Although little is known about the presence of these chemicals in the environment, recent studies suggested that soil may act as a sink. The aim of the present work was to investigate the presence of fullerenes in soils collected in The Netherlands. Samples (n = 91) were taken from 6 locations and analyzed using a new developed LC-QTOF-MS method. The locations included highly trafficked and industrialized as well as urban and natural areas. In general, C60 was the most abundant fullerene found in the environment, detected in almost a half of the samples and at concentrations in the range of ng/kg. Other fullerenes such as C70 and an unknown structure containing a C60 cage were detected to a lower extent. The highest concentrations were found in the proximity of combustion sites such as a coal power plant and an incinerator, suggesting that the nanoparticles were unintentionally produced during combustions processes and reached the soil through atmospheric deposition. Consistent with other recent studies, these results show that fullerenes are widely present in the environment and that the main route for their entrance may be due to human activities. These data will be helpful in the understanding of the distribution of fullerenes in the environment and for the study of their behavior and fate in soil.


Asunto(s)
Fulerenos/análisis , Fulerenos/química , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química , Cromatografía Liquida , Monitoreo del Ambiente , Espectrometría de Masas , Países Bajos
16.
J Chromatogr A ; 1433: 123-30, 2016 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-26810805

RESUMEN

The increasing production of fullerenes likely means a release of these chemicals in the environment. Since soils and sediments are expected to act as a sink, analytical tools are needed to assess the presence of fullerenes in these matrices. In the present work, a method was developed for the determination of fullerenes at environmental relevant levels employing Ultra High Performance Liquid Chromatograph coupled with High Resolution Mass Spectrometry (UHPLC-HRMS). Chromatographic separation was achieved with a core-shell biphenyl stationary phase that provided fast analysis with complete baseline separation. Ion Booster Electro Spray Ionization (IB-ESI) resulted in higher ionization efficiency and was much less susceptible to adduct formation in comparison with standard ESI, whereas Quadrupole Time of Flight (QTOF) MS granted high resolution mass spectra used for accurate identification. The Instrumental method limits of detection (ILoD) and quantification (ILoQ) were 6 and 20 fg, respectively, for C60 and 12 and 39 fg, respectively, for C70. Matrix effects related to co-extractants were systematically investigated in soil and sediments extracts through standard addition method (SAM) and monitoring the signal response during the chromatographic run of these samples. Consequently, minor chromatographic modifications were necessary for the analysis of matrices with high organic carbon content. The method limit of detection (MLoD)ranged from 84 pg/kg to 335 pg/kg, whereas limit of quantification (MLoQ) ranged from 279 pg/kg to 1.1 ng/kg. Furthermore, the method was successfully applied for the analysis of functionalized fullerenes (i.e. methanofullerenes). To the best of our knowledge, this is the first analytical method for the analysis of fullerenes in soils and sediments that employ core-shell biphenyl stationary phase as well as IB-ESI-QTOF MS hyphenated with UHPLC.


Asunto(s)
Fulerenos/análisis , Sedimentos Geológicos/análisis , Contaminantes del Suelo/análisis , Contaminantes del Agua/análisis , Cromatografía Líquida de Alta Presión/métodos , Suelo/química , Espectrometría de Masa por Ionización de Electrospray
17.
New Phytol ; 209(4): 1781-94, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26526745

RESUMEN

Here we studied the organization of genetic variation of the common bean (Phaseolus vulgaris) in its centres of domestication. We used 131 single nucleotide polymorphisms to investigate 417 wild common bean accessions and a representative sample of 160 domesticated genotypes, including Mesoamerican and Andean genotypes, for a total of 577 accessions. By analysing the genetic spatial patterns of the wild common bean, we documented the existence of several genetic groups and the occurrence of variable degrees of diversity in Mesoamerica and the Andes. Moreover, using a landscape genetics approach, we demonstrated that both demographic processes and selection for adaptation were responsible for the observed genetic structure. We showed that the study of correlations between markers and ecological variables at a continental scale can help in identifying local adaptation genes. We also located putative areas of common bean domestication in Mesoamerica, in the Oaxaca Valley, and the Andes, in southern Bolivia-northern Argentina. These observations are of paramount importance for the conservation and exploitation of the genetic diversity preserved within this species and other plant genetic resources.


Asunto(s)
Adaptación Fisiológica/genética , Variación Genética , Phaseolus/genética , Phaseolus/fisiología , Arqueología , Biomasa , Núcleo Celular/genética , Cloroplastos/genética , Geografía , Polimorfismo de Nucleótido Simple/genética , Semillas/genética
19.
Anal Chim Acta ; 807: 159-65, 2014 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-24356233

RESUMEN

Fullerenes are carbon-based nanomaterials expected to play a major role in emerging nanotechnology and produced at an increasing rate for industrial and household applications. In the last decade a number of novel compounds (i.e. fullerene derivatives) is being introduced into the market and specific analytical methods are needed for analytical purposes as well as environmental and safety issues. In the present work eight fullerenes (C60 and C70) and functionalized fullerenes (C60 and C70 exohedral-derivatives) were selected and a novel liquid chromatographic method was developed for their analysis with UV absorption as a method of detection. The resulting HPLC-UV method is the first one suitable for the analysis of all eight compounds. This method was applied for the analysis of fullerenes added to clayish, sandy and loess top-soils at concentrations of 20, 10 and 5 µg kg(-1) and extracted with a combination of sonication and shaking extraction. The analytical method limits of detection (LoD) and limits of quantification (LoQ) were in the range of 6-10 µg L(-1) and 15-24 µg L(-1) respectively for the analytical solutions. The extraction from soil was highly reproducible with recoveries ranging from 47±5 to 71±4% whereas LoD and LoQ for all soils tested were of 3 µg kg(-1) and 10 µg kg(-1) respectively. No significant difference in the extraction performance was observed depending of the different soil matrices and between the different concentrations. The developed method can be applied for the study of the fate and toxicity of fullerenes in complex matrices at relatively low concentrations and in principle it will be suitable for the analysis of other types of functionalized fullerenes that were not included in this work.

20.
Anal Chem ; 85(12): 5867-74, 2013 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-23705858

RESUMEN

One of the main challenges in environmental risk assessment of fullerenes is to develop analytical methods that detect and quantify fullerenes at low concentrations. In this paper we report on the development and optimization of a highly specific, robust, and relatively simple method for the quantitative determination of C60, C70, and six functionalized fullerenes, namely, [6,6]-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C61-butyric acid butyl ester, [6,6]-phenyl-C61-butyric acid octyl ester, [6,6]-bis(phenyl)-C61-butyric acid methyl ester, [6,6]-thienyl-C61-butyric acid methyl ester, and [6,6]-phenyl-C71-butyric acid methyl ester ([70PCBM], in different aqueous matrixes. For this method fullerenes were extracted from the aqueous phase using solid-phase extraction (SPE), with subsequent analysis on a liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS) system. SPE was optimized by varying different conditions to improve recovery of all fullerenes. Different SPE column materials (C18, C18e, C8, CN) were tested, and recoveries appeared to be the highest for the C18-material. Recoveries were improved by adding NaCl to the water during extraction. Very low limit of detection (LOD) values were obtained for all compounds with this method, ranging from 0.17 ng/L for [70]PCBM to 0.28 ng/L for C60, and subsequent limit of quantitation (LOQ) values of 0.57-0.91 ng/L. Recoveries for the fullerenes were on average 120% in ultrapure and drinking water. Recoveries appeared to be lower, but still acceptable (e.g., >78%), in surface water. The developed approach is promising and will be applied, for example, in (1) environmental monitoring, (2) a more in-depth study of environmental fate and transformation products, and (3) studying water treatment efficiency of C60, C70, and the various functionalized fullerenes.


Asunto(s)
Fulerenos/análisis , Espectrometría de Masas en Tándem/métodos , Contaminantes Químicos del Agua/análisis , Agua/análisis , Cromatografía Liquida/métodos , Espectrometría de Masas/métodos
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