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1.
Polymers (Basel) ; 16(3)2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38337248

RESUMO

In this study, four different plastic materials usually used in the agricultural sector (polystyrene film (PS), polyethylene terephthalate film (PET), low-density polyethylene film (LDPE) and linear low-density polyethylene film (LLDPE)) were subjected to different abiotic treatments, including photo-oxidation (ultraviolet and e-beam radiation) and thermochemical treatments, to enhance polymer degradation. The extensive use of these polymers leads to large amounts of plastic waste generation, including small plastic pieces, known as microplastics, which affect the quality of the agricultural environment, including soil fertility and quality. Therefore, polymer degradation strategies are needed to effectively reduce plastic waste to protect the agricultural sector. The degree of polymer degradation was assessed by the use of thermal and spectroscopic analyses, such as TGA and FTIR. In addition, efficiency, cost-benefits, and potential side-effects were also evaluated to propose the optimal degradation strategy to reduce plastic waste from the point of view of efficiency. The results obtained showed that the pre-treatments based on photo-oxidation (ultraviolet B and C and e-beam radiation) were more efficient and had a better cost-benefit for the degradation of the polymers studied in relation to the thermochemical treatments. Specifically, ultraviolet photo-oxidation worked well for PS and PET, requiring low energy and medium times. However, e-beam radiation was recommended for PE (LDPE and LLDPE) degradation, since high energy and long times were needed when ultraviolet energy was applied to this polymer. Furthermore, the overall efficiency of the plastic degradation of pre-treatments should be studied using a multicriteria approach, since FTIR assessments, in some cases, only consider oxidation processes on the plastic surface and do not show the potential integrity changes on the plastic probes.

2.
PLoS One ; 18(10): e0291516, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37792682

RESUMO

The settlement of cold and arid environments by Pleistocene hunter-gatherers has been a heated topic in Paleolithic Archaeology and the Quaternary Sciences for years. In the Iberian Peninsula, a key area for studying human adaptations to such environments is composed by the large interior and upland regions of the northern and southern plateaus (Mesetas) and bordering areas. As, traditionally, these regions have been relatively under-investigated compared to the ecologically more favored coastal areas of the peninsula, our knowledge of the human settlement of the whole Iberian hinterland remains scarce for the Last Glacial. In this paper we present the discovery and first geoarcheological, paleoenvironmental and chronometric evidence obtained at Charco Verde II, a new site close to the southwestern foothills of the Iberian system range (Guadalajara province, Spain), bearing a sequence of Magdalenian human occupations starting at least at 20.8-21.4 ka cal BP during the Last Glacial Maximum, and covering Greenland Stadial 2 until ∼15.1-16.6 ka cal BP, including Heinrich stadial 1. As this site is located in an upland region which today faces one of the harshest climates in Iberia, such occupation sequence, occurred during some of the coldest and most arid phases of the Last Glacial, has relevant implications for our understanding of human-environment-climate interactions and population dynamics in Iberia and Western Europe. These findings support the hypothesis that the Iberian hinterland was not avoided by Upper Paleolithic hunter-gatherers due to ecological constraints, but it hosted a complex and relatively dense settlement at least in some areas, even during cold periods. This suggest, one more time, that the historical scarcity of Upper Paleolithic sites in inland Iberia is, to a significant extent, an artifact of research bias.


Assuntos
Arqueologia , Clima , Humanos , Espanha , Europa (Continente) , Dinâmica Populacional
3.
Sci Total Environ ; 697: 133989, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31484092

RESUMO

The effects of climate change on forest growth are not homogeneous across tree species distribution ranges because of inter-population variability and spatial heterogeneity. Although latitudinal and thermal gradients in growth patterns have been widely investigated, changes in these patterns along longitudinal gradients due to the different timing and severity of regional droughts are less studied. Here, we investigated these responses in Mediterranean Black pine (Pinus nigra Arn.). We built a tree-ring width dataset comprising 77 forests (1202 trees) across the Mediterranean Basin. The biogeographical patterns in growth patterns and the relationships between growth and mean temperature, precipitation, drought and atmospheric circulations patterns (NAO -North Atlantic Oscillation-, SOI -Southern Oscillation Index- and MOI -Mediterranean Oscillation index-) were analyzed. Then, we evaluated the spatial and temporal growth synchrony between and within east and west populations. We found different growth and climate patterns in west vs. east Black pine populations, although in both regions growth was driven by similar temperature and precipitation variables. MOI significantly influenced tree growth, whilst NAO and SOI showed weaker effects. Growth of east and west Black pine populations desynchronized after the 1970s when several and uncoupled regional droughts occurred across the Mediterranean Basin. We detected a climate shift from the 1970s to the 1980s affecting growth patterns, changing growth-climate relationships, and reducing forest growth from west to east Black pine forests. Afterwards, climate and growth of east and west populations became increasingly more divergent. Our findings imply that integral bioclimatic and biogeographical analyses across the species distribution area must be considered to adequately assess the impact of climate change on tree growth under warming and more arid conditions.


Assuntos
Mudança Climática , Secas , Pinus/fisiologia , Fenômenos Biológicos , Florestas , Região do Mediterrâneo
4.
PLoS One ; 13(9): e0203754, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30208080

RESUMO

BACKGROUND: Overweight, obesity, and gestational diabetes (GD) during pregnancy may negatively affect neurodevelopment in the offspring. However, the mechanisms are unclear and objective measures of neurodevelopment in infancy are scarce. We hypothesized that these maternal metabolic pathologies impair cortical visual evoked potentials (cVEPs), a proxy for visual and neuronal maturity. DESIGN: The PREOBE study included 331 pregnant women stratified into four groups; normal weight (controls), overweight, obesity, and GD (the latter including mothers with normal weight, overweight and obesity). In a subsample of the offspring at 3 months (n = 157) and at 18 months (n = 136), we assessed the latencies and amplitudes of the P100 wave from cVEPs and calculated visual acuity. RESULTS: At 3 months of age, visual acuity was significantly poorer in offspring born to GD mothers. At 18 months of age, there were no differences in visual acuity but infants born to GD mothers had significantly longer latencies of cVEPs when measured at 15', and 30' of arc. The group differences at 30' remained significant after confounder adjustment (mean [SD] 121.0 [16.0] vs. 112.6 [7.6] ms in controls, p = 0.007) and the most prolonged latencies were observed in offspring to GD mothers with concurrent overweight (128.9 [26.9] ms, p = 0.002) and obesity (118.5 [5.1] ms, p = 0.020). CONCLUSIONS: Infants born to mothers with GD, particularly those with concurrent overweight or obesity, have prolonged latencies of visual evoked potentials at 18 months of age, suggesting that this maternal metabolic profile have a long lasting, non-optimal, effect on infants´ brain development.


Assuntos
Diabetes Gestacional/patologia , Potenciais Evocados Visuais/fisiologia , Obesidade/patologia , Sobrepeso/patologia , Adolescente , Adulto , Glicemia/análise , Índice de Massa Corporal , Estudos de Coortes , Feminino , Ferritinas/sangue , Humanos , Lactente , Estado Civil , Pessoa de Meia-Idade , Mães , Transtornos do Neurodesenvolvimento/diagnóstico , Gravidez , Acuidade Visual , Adulto Jovem
5.
PLoS One ; 12(7): e0180823, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28723924

RESUMO

INTRODUCTION AND OBJECTIVES: Although the Iberian Peninsula is a key area for understanding the Middle to Upper Paleolithic transition and the demise of the Neandertals, valuable evidence for these debates remains scarce and problematic in its interior regions. Sparse data supporting a late Neandertal persistence in the Iberian interior have been recently refuted and hence new evidence is needed to build new models on the timing and causes of Neandertal disappearance in inland Iberia and the whole peninsula. In this study we provide new evidence from Los Casares, a cave located in the highlands of the Spanish Meseta, where a Neandertal-associated Middle Paleolithic site was discovered and first excavated in the 1960's. Our main objective is twofold: (1) provide an updated geoarcheological, paleoenvironmental and chronological framework for this site, and (2) discuss obtained results in the context of the time and nature of the last Neandertal presence in Iberia. METHODS: We conducted new fieldwork in an interior chamber of Los Casares cave named 'Seno A'. Our methods included micromorphology, sedimentology, radiocarbon dating, Uranium/Thorium dating, palinology, microfaunal analysis, anthracology, phytolith analysis, archeozoology and lithic technology. Here we present results on site formation processes, paleoenvironment and the chronological setting of the Neandertal occupation at Los Casares cave-Seno A. RESULTS AND DISCUSSION: The sediment sequence reveals a mostly in situ archeological deposit containing evidence of both Neandertal activity and carnivore action in level c, dated to 44,899-42,175 calendar years ago. This occupation occurred during a warm and humid interval of Marine Isotopic Stage 3, probably correlating with Greenland Interstadial 11, representing one of the latest occurrences of Neandertals in the Iberian interior. However, overlying layer b records a deterioration of local environments, thus providing a plausible explanation for the abandonment of the site, and perhaps for the total disappearance of Neandertals of the highlands of inland Iberia during subsequent Greenland Stadials 11 or 10, or even Heinrich Stadial 4. Since layer b provided very few signs of human activity and no reliable chronometric results, and given the scarce chronostratigrapic evidence recorded so far for this period in interior Iberia, this can only be taken as a working hypothesis to be tested with future research. Meanwhile, 42,000 calendar years ago remains the most plausible date for the abandonment of interior Iberia by Neandertals, possibly due to climate deterioration. Currently, a later survival of this human species in Iberia is limited to the southern coasts.


Assuntos
Arqueologia , Fósseis , Homem de Neandertal , Animais , Cavernas , Clima , Datação Radiométrica , Espanha , Tecnologia
6.
Sci Total Environ ; 573: 1159-1170, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26996521

RESUMO

Mid-Late Holocene environmental changes in the Cantabrian Mountains are a consequence of both climate variability and human activity. A 182cm-long sedimentary sequence was collected from Belbín depression, Western Massif of Picos de Europa (Cantabrian Mountains, NW Spain), in order to reconstruct Holocene environmental dynamics and the factors triggering landscape changes in the area. Using multi-proxy analysis of the uppermost 60cm of the sediments (texture, organic matter content, quartz grains microstructures, charcoal deposition) together with three 14C AMS dates, a sequence of alternating warmer and colder phases has been inferred for the last ca. 6.7kycalBP. Warm stages are defined by low to moderate chemical weathering of the quartz grain particles with relative increases of the C/N ratio, while colder phases show a moderate to intense physical weathering of the quartz grains and lower C/N ratios. Warmer temperatures were recorded in Belbín area between: 6.7-5, 3.7-3, 2.6-1.1, 0.87-0.51 and since 0.01kycalBP. A colder regime occurred between 5-3.7, 3-2.6, 1.1-0.87 and 0.51 to 0.01kycalBP. The increasing organic matter content during the Late Holocene may be associated with increasing temperatures. The charcoal particles do not show a higher or lower concentration during prevailing colder or warmer conditions, and therefore may be linked to human-induced fire management of the landscape. The most intense period with fire activity occurred between 3.5 and 3kycalBP during the Bronze Age.

8.
Exp Parasitol ; 130(2): 152-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22101110

RESUMO

The development of nanotechnology has generated new means of disease diagnosis and treatment. Infectious diseases, including leishmaniasis, malaria, etc., have benefited from the advent of new nanomaterials and/or nanodevices capable of detecting specific antigens and antibodies with high specificity and low cost. In this paper, we present an investigation on a single-celled protozoan Leishmaniasis parasite, a disease considered of standard infectivity, given the high degree of immunological specificity. Natural rubber (NR) membranes incorporating gold nanoparticles (GNPs) were placed in the culture medium and the physiological behavior of Leishmania brasiliensis promastigotes was evaluated. The natural rubber membranes containing GNPs decreased the population growth rate, showing a lower index of living promastigotes (attached to the membrane surface) depending on the amount of nanoparticles deposited in the membrane surface. Such membranes may be used to develop a flexible band-aid for skin lesions from degenerative infection state, inhibiting the population growth of parasites in the lesions. In addition, natural rubber membranes would also stimulate angiogenesis in damaged tissues.


Assuntos
Curativos Hidrocoloides , Ouro/farmacologia , Leishmania braziliensis/fisiologia , Nanopartículas Metálicas , Borracha , Meios de Cultura , Leishmania braziliensis/efeitos dos fármacos , Leishmania braziliensis/crescimento & desenvolvimento , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/terapia , Membranas Artificiais
9.
Analyst ; 135(10): 2591-9, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20714515

RESUMO

The combination of metallic phthalocyanines (MPcs) and biomolecules has been explored in the literature either as mimetic systems to investigate molecular interactions or as supporting layers to immobilize biomolecules. Here, Langmuir-Blodgett (LB) films containing the phospholipid dimyristoyl phosphatidic acid (DMPA) mixed either with iron phthalocyanine (FePc) or with lutetium bisphthalocyanine (LuPc(2)) were applied as ITO modified-electrodes in the detection of catechol using cyclic voltammetry. The mixed Langmuir films of FePc + DMPA and LuPc(2) + DMPA displayed surface-pressure isotherms with no evidence of molecular-level interactions. The Fourier Transform Infrared (FTIR) spectra of the multilayer LB films confirmed the lack of interaction between the components. The DMPA and the FePc molecules were found to be oriented perpendicularly to the substrate, while LuPc(2) molecules were randomly organized. The phospholipid matrix induced a remarkable electrocatalytic effect on the phthalocyanines; as a result the mixed LB films deposited on ITO could be used to detect catechol with detection limits of 4.30 × 10(-7) and 3.34 × 10(-7) M for FePc + DMPA and LuPc(2) + DMPA, respectively. Results from kinetics experiments revealed that ion diffusion dominated the response of the modified electrodes. The sensitivity was comparable to that of other non-enzymatic sensors, which is sufficient to detect catechol in the food industry. The higher stability of the electrochemical response of the LB films and the ability to control the molecular architecture are promising for further studies with incorporation of biomolecules.


Assuntos
Catecóis/análise , Técnicas Eletroquímicas/métodos , Compostos Ferrosos/química , Glicerofosfolipídeos/química , Indóis/química , Eletrodos , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Phys Chem Chem Phys ; 12(16): 3972-83, 2010 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-20379489

RESUMO

The application of organic thin films as transducer elements in electronic devices has been widely exploited, with the electrostatic layer-by-layer (LbL) technique being one of the most powerful tools to produce such films. The conventional LbL method, however, is restricted in many cases to water soluble compounds. Here, an alternative way to produce LbL films containing iron phthalocyanine (FePc) in non-aqueous media (chloroform) is presented. This film fabrication was made possible by exploiting the specific interactions between Fe and NH(2) groups from PAH, poly(allylamine hydrochloride) used as the supporting layer, leading to the formation of bilayers structured as (PAH/FePc)(n). We have also incorporated silver nanoparticles (AgNPs) in LbL films with (PAH/FePc/AgNP)(n) trilayers, making it possible to achieve the surface-enhanced Raman scattering (SERS) phenomenon. The molecular architecture of the LbL films was determined through different techniques. The growth was monitored with UV-Vis absorption spectroscopy, their morphology characterized by optical and scanning electron (SEM) microscopes, and their molecular organization determined using FTIR. The electrochemical properties of the LbL films were successfully applied in detecting dopamine in KCl aqueous solutions at different concentrations using cyclic voltammetry. The results confirmed that the LbL films from FePc in non-aqueous media keep their electroactivity, while showing an interesting electrocatalytic effect. The SERS phenomenon suggested that FePc aggregates might be directly involved in the maintenance of the electroactivity of the LbL films.

11.
Nature ; 443(7113): 850-3, 2006 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-16971951

RESUMO

The late survival of archaic hominin populations and their long contemporaneity with modern humans is now clear for southeast Asia. In Europe the extinction of the Neanderthals, firmly associated with Mousterian technology, has received much attention, and evidence of their survival after 35 kyr bp has recently been put in doubt. Here we present data, based on a high-resolution record of human occupation from Gorham's Cave, Gibraltar, that establish the survival of a population of Neanderthals to 28 kyr bp. These Neanderthals survived in the southernmost point of Europe, within a particular physiographic context, and are the last currently recorded anywhere. Our results show that the Neanderthals survived in isolated refuges well after the arrival of modern humans in Europe.


Assuntos
Fósseis , Hominidae/fisiologia , Animais , Gibraltar , História Antiga , Humanos , Dinâmica Populacional , Fatores de Tempo
12.
Rev. venez. anestesiol ; 9(1): 12-19, jun. 2004. tab, graf
Artigo em Espanhol | LILACS | ID: lil-447523

RESUMO

Comparar los tiempos de recuperación del bromuro de rocuronio a 0,3 mg/kg y 0,6 mg/Kg para anestesia general con sevoflurano y óxido nitroso en preescolares y escolares. Previo consentimiento informado, se estudiaron 66 niños, ASA I-II, programados para cirugía electiva, distribuidos en dos grupos, preescolares (2-6 años) y escolares (7-12 años). La inducción anestésica fue inhalatoria con sevoflurano y NO2/O2, intravenosa con fentanyl 1 µg/kg, lidocaína 1,5 mg/kg, propofol 2 mg/kg. La monitorización se hizo por aceleromiografía (TOF-Guard) para la estimulación del nervio cubital. Posterior a la administración el bromuro de rocuronio se registraron los tiempos de recuperación espontánea del D25 y T75; índice de recuperación 25-75 y el TOF al 0,7 y 0,9. Los grupos resultaron estadísticamente homogéneos. Se obtuvieron similares tiempos de recuperación en los preescolares respecto a los escolares, con una prolongación estadísticamente significativa en el T75 a 0,6 mg/kg (P < 0,05) en los preescolares. Se encontró una correlación negativa entre la D25 y la edad, sin diferencia en los otros tiempos medidos


Assuntos
Masculino , Pré-Escolar , Humanos , Feminino , Criança , Brometos , Período de Recuperação da Anestesia , Venezuela , Anestesiologia
13.
Phytochemistry ; 62(7): 1145-51, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12591270

RESUMO

Dried mosses (five moss species) were progressively extracted and subjected to a four-step Craig distribution. Seven pure flavonoids were isolated and identified. The flavonoids were the flavones apigenin, apigenin-7-O-triglycoside, lucenin-2, luteolin-7-O-neohesperidoside, saponarine and vitexin; and the biflavonoid bartramiaflavone and they were submitted to biological tests. The tests were performed in vitro on spore germination and protonemal growth of the moss Tortula muralis and on seed germination and root growth of Raphanus sativus. Flavonoids caused a decrease in the percentage of spore germination, protonemal development and root growth. In addition they caused morphological alterations, such as forked tips, swollen apices, rounded cells and early formation of brood cells in the protonemata. Data were discussed in relation to the presence of allelochemicals in mosses.


Assuntos
Brassica/efeitos dos fármacos , Brassica/crescimento & desenvolvimento , Bryopsida/química , Flavonoides/química , Flavonoides/farmacologia , Hepatófitas/efeitos dos fármacos , Hepatófitas/crescimento & desenvolvimento , Flavonoides/isolamento & purificação , Germinação/efeitos dos fármacos , Hepatófitas/fisiologia , Microscopia/métodos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Esporos/efeitos dos fármacos , Esporos/crescimento & desenvolvimento , Fatores de Tempo
14.
Rev. venez. anestesiol ; 3(1): 3-7, ene.-jun. 1998. tab
Artigo em Espanhol | LILACS | ID: lil-263260

RESUMO

La Ventilación Jet Transtraqueal (VJTT) sistema de alto flujo de oxígeno, administrado a través de un catéter de grueso calibre, insertado en la membrana cricotiroidea. El objetivo principal es demostrar su utilidad en procedimientos electivos, mediante el mantenimiento de una adecuada oxigenación, ventilación y estabilidad hemodinámica. Veinte pacientes, ASA I o II, mayores de 18 años, programados para intervenciones electivas, menores de 90 minutos. Posterior a la inducción anestésica se inició la VJTT, con controles gasométricos a los 0 y 30 minutos, monitoreo oximétrico, presión arterial, frecuencia y ritmo cardíaco. Los resultados cuantitativos se expresaron en Promedios y Desviación Standard, se aplicó la t de Student. Los datos cualitativos en Porcentajes. La oxigenación fue adecuada en todos los pacientes, manteniendo una PaO2 media de 317 ñ 116,71 mm de Hg y saturación de Oxígeno de 98,78 ñ 0,71 por ciento. Los cambios del pH a los 0 y 30 minutos, mostraron variación significativa, sin importancia clínica. Las presiones arteriales de CO2 se encontraron elevadas en 4 pacientes; en dos acompañadas de un pH disminuido. Las variables hemodinámicas, no se modificaron en el transoperatorio. El 90 por ciento de los pacientes presentaron o no complicaciones leves. Concluimos que la VJTT es un procedimiento seguro, para ser usado en forma electiva; constituye un sistema para la oxigenación y ventilación del paciente, tanto clínico como gasométrico


Assuntos
Humanos , Masculino , Feminino , Adulto , Fisiologia , Oxigenação , Ventilação em Jatos de Alta Frequência
15.
Med. crít. venez ; 10(2): 56-9, mayo-ago. 1995. ilus
Artigo em Espanhol | LILACS | ID: lil-234634

RESUMO

Reportamos el caso de un paciente masculino de 44 años de edad, con limitación en la apertura bucal posterior a accidente de tránsito, quien fue programado para amputación infracondilea del miembro inferior derecho, bajo anestesia general. Por resultar fallidos múltiples intentos de intubación orotraqueal se decide iniciar la Ventilación Jet Transtraqueal (VJTT), a través de un catéter Nº14 colocado a través de la membrana cricotiroidea, con una presión de 30 PSI; siendo adecuada la oxigenación y ventilación durante todo el procedimiento quirúrgico. No se presentó ninguna complicación en el trans y postoperatorio. Este reporte es el primer caso de VJTT usada en una emergencia en el Hospital Militar "Dr. Carlos Arvelo"


Assuntos
Humanos , Masculino , Adulto , Anestesia/estatística & dados numéricos , Cirurgia Geral/métodos , Intubação/métodos , Membranas/anormalidades , Traqueia/anormalidades
16.
Z Naturforsch C J Biosci ; 50(3-4): 311-312, 1995 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-37978779

RESUMO

From Bartramia ithyphylla the following five biflavonoids were isolated: philonotisflavone, 2,3-dihydrophilonotisflavone, dicranolomin, 5',3'''-dihydroxyamentoflavone and 5'-hydroxyamentoflavone.

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