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1.
J Thorac Cardiovasc Surg ; 166(5): 1458-1467, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-35279289

RESUMO

OBJECTIVE: The study objective was to assess the benefits of del Nido cardioplegia compared with cold blood cardioplegia solution in terms of myocardial protection during adult cardiac surgery. METHODS: A total of 474 adult patients undergoing coronary artery bypass grafting, heart valve surgery, thoracic aortic surgery, or combined procedures were randomized to the del Nido cardioplegia group (n = 234) or the cold blood cardioplegia solution group (n = 240) after provided informed consent. The primary end points assessed inotropic support requirements, severe cardiovascular events, and troponin trend within the first 48 hours of intensive care unit stay. Reperfusion arrhythmias, aortic crossclamp and cardiopulmonary bypass times, and other clinical perioperative variables were considered as secondary end points. RESULTS: No statistically significant differences were found regarding postoperative inotropic support requirements or the incidence of severe cardiovascular events. The del Nido cardioplegia group showed a higher return to spontaneous sinus rhythm (P< .001), a lower number of defibrillation attempts (P< .001), and an earlier peak troponin value in the postoperative period. Peak blood glucose levels and intravenous insulin requirements were significantly lower in the del Nido cardioplegia group. We found no significant differences regarding aortic crossclamp or cardiopulmonary bypass time. We did observe a lower incidence of postoperative stroke in the del Nido cardioplegia group (2.6% vs 6.7%; P= .035). CONCLUSIONS: del Nido cardioplegia can be used safely and with comparable outcomes compared with traditional cardioplegia solutions. Additional advantages over glycemic control, reperfusion arrhythmias, and its comfortable redosing interval make del Nido an interesting alternative for myocardial protection in adult cardiac surgery. A significant decrease in postoperative stroke will require further research to shed light on the results of this study. VIDEO ABSTRACT.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Doenças Cardiovasculares , Acidente Vascular Cerebral , Cirurgia Torácica , Humanos , Adulto , Estudos Prospectivos , Parada Cardíaca Induzida/efeitos adversos , Parada Cardíaca Induzida/métodos , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Soluções Cardioplégicas/efeitos adversos , Troponina , Estudos Retrospectivos
2.
Rev Esp Cardiol (Engl Ed) ; 75(7): 552-558, 2022 Jul.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-34481752

RESUMO

INTRODUCTION AND OBJECTIVES: Pregnancy in women with Marfan syndrome (MS) is associated with an increased risk of aortic events. The clinical evidence on pregnant patients with MS is limited and there is no specific consensus on their optimal management. We report our multicenter experience. METHODS: From January 2004 to January 2020, 632 patients with MS underwent periodic monitoring in Marfan units. During this period, we identified all pregnant women with MS and analyzed the incidence of aortic events during pregnancy and puerperium. RESULTS: There were 133 pregnancies in 89 women with MS (8 women with prior aortic surgery). There were no maternal deaths, but 5 women had aortic events during the third trimester and puerperium (type A dissections in 2, type B dissection in 1, and significant [≥ 3mm] aortic growth in 2). The aortic event rate was 3.7%. Pregestational aortic diameter≥ 40mm showed a nonsignificant association with aortic events (P=.058). Fetal mortality was 3% and 37.6% of births were cesarean deliveries. CONCLUSIONS: Women with MS have an increased risk of aortic events during pregnancy, especially in the third trimester and postpartum period. Patients with MS and aortic diameters ≥40mm should be assessed in experienced centers for prophylactic aortic surgery before pregnancy. It is important to provide early diagnosis, prepregnancy study of the aorta, beta-blocker administration, and close monitoring during pregnancy, especially during the last trimester and postpartum.


Assuntos
Síndrome de Marfan , Complicações Cardiovasculares na Gravidez , Aorta , Cesárea/efeitos adversos , Feminino , Humanos , Incidência , Síndrome de Marfan/complicações , Síndrome de Marfan/diagnóstico , Síndrome de Marfan/epidemiologia , Gravidez , Complicações Cardiovasculares na Gravidez/epidemiologia
3.
Gerokomos (Madr., Ed. impr.) ; 32(1): 57-62, mar. 2021. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-202050

RESUMO

OBJETIVOS: Identificar el nivel de conocimiento, actitud y práctica orientada a la prevención del pie diabético en personas ingresadas o sus cuidadores principales en la Unidad de Cirugía Vascular. METODOLOGÍA: Se realizó un análisis estadístico descriptivo transversal. Las variables analizadas fueron: conocimiento, actitud y comportamientos relacionados con el cuidado del pie diabético. Desde diciembre de 2016 a diciembre de 2017, un equipo de enfermeras facilitó un cuestionario durante el ingreso de los pacientes en la Unidad de Cirugía Vascular, el cual no se había utilizado anteriormente con población española. RESULTADOS: El tamaño de la muestra se calculó con el objetivo de conseguir 189 personas. Un total de 172 respondió el cuestionario. En la dimensión de conocimiento, la media fue de 6,56 sobre 10 (DE = 2,05). El nivel de conocimiento de un 58,2% fue medio. En la dimensión de actitud, la media fue de 4,42 sobre 5 (DE = 0,95). Un 93% declaró tener actitud favorable hacia el autocuidado de sus pies. En la dimensión de práctica orientada a la prevención, la media fue de 5,45 (DE = 2,55). El 51,5% realizó una práctica media de autocuidado del pie diabético. CONCLUSIONES: Las personas poseían conocimientos medios de los cuidados del pie diabético. Al preguntarles por su actitud, esta fue favorable. Contrasta con el nivel de comportamiento en la práctica de autocuidado, que en la mitad de la muestra fue de carácter medio, repartiendo en partes iguales la buena práctica con la escasa práctica de autocuidado


BACKGROUND: To identify the level of knowledge, attitude and practice oriented to the prevention of diabetic foot in hospitalized persons or their main caregivers in the Vascular Surgery Unit. METHODS: A transversal descriptive statistical analysis was carried out. The variables analyzed were: knowledge, attitude and behavior related to the care of the diabetic foot. A team of six nurses, provided a questionnaire during the period of admission of patients from December 2016 to December 2017, which had not previously been used with Spanish population. RESULTS: The sample size was calculated in order to get 189 people. A total of 172 people answered the questionnaire. In the Knowledge Dimension, the mean was (6.56) out of 10 (SD = 2.05). The level of knowledge of 58.2% was medium. In Attitude, the average was 4.42 out of 5 (SD = 0.95). 93% say they are favorable towards self-care of their feet. In Practice oriented to prevention, the average was 5.45 (SD = 2.55). 51.5% perform an average self-care practice of diabetic foot. CONCLUSIONS: The people in the study had average knowledge of diabetic foot care. When asked about their attitude, this was favorable. It contrasts with the level of behavior in the practice of self-care, which in the middle of the sample was of average character, distributing in equal parts the good practice with the scarce practice of self-care


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Pé Diabético/prevenção & controle , Complicações do Diabetes/epidemiologia , Procedimentos Cirúrgicos Vasculares/métodos , Conhecimentos, Atitudes e Prática em Saúde , Cuidadores/estatística & dados numéricos , Pé Diabético/enfermagem , Autocuidado/métodos , Fragilidade/epidemiologia , Estudos Transversais
4.
Rev Esp Cardiol (Engl Ed) ; 74(1): 33-43, 2021 Jan.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-32448727

RESUMO

INTRODUCTION AND OBJECTIVES: Mortality remains high in cardiogenic shock (CS), especially in refractory CS involving the use of mechanical circulatory support (MCS) devices. The aim of this study was to analyze the results of a care program for patients in CS after the creation of a multidisciplinary team in our center and a regional network of hospitals in our area. METHODS: Observational and retrospective study of patients attended in this program from September 2014 to January 2019. We included patients in refractory CS who required MCS and those who, because of their age and absence of comorbidities, were candidates for advanced therapies. The primary endpoint was survival to discharge. RESULTS: A total of 130 patients were included (69 local and 61 transferred patients). The mean age was 52±15 years (72% men). The most frequent causes of CS were acute decompensated heart failure (29%), acute myocardial infarction (26%), and postcardiotomy CS (25%). MCS was used in 105 patients (81%), mostly extracorporeal membrane oxygenation (58%). Survival to discharge was 57% (74 of 130 patients). The most frequent destinations were myocardial recovery and heart transplant. Independent predictors of in-hospital mortality were SAPS II score, lactate level, acute myocardial infarction etiology, and vasoactive-inotropic score. CONCLUSIONS: The creation of multidisciplinary teams for patients with mainly refractory CS and a regional network is feasible and allows survival to discharge in more than a half of attended patients with CS.


Assuntos
Choque Cardiogênico , Adulto , Idoso , Feminino , Coração Auxiliar , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Choque Cardiogênico/epidemiologia , Choque Cardiogênico/terapia , Fatores de Tempo , Resultado do Tratamento
7.
Ann Thorac Surg ; 109(6): 1850-1857, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31589859

RESUMO

BACKGROUND: The purpose of this study was to analyze the risk of aortic events (death, dissection, or aortic rupture) associated with Marfan syndrome and decide on the optimal timing for preventive surgery on the aortic root. METHODS: From January 2004 to June 2015, 397 patients from Marfan Units were studied by echocardiographic and computed tomography and magnetic resonance imaging of aorta and periodic annual monitoring. Mean follow-up was 5.6 ± 2.7 years. The annual incidence of aortic events was assessed according to aortic diameters for the optimal time for prophylactic surgery to be decided on. RESULTS: Mean age at the first visit was 28.4 ± 14.5 years, with mean sinuses of Valsalva diameter of 37.1 ± 6.6 mm., Eleven aortic events occurred during follow-up: seven deaths and four acute aortic dissections. Mean annual risk of an aortic event was 0.5% (risk of death 0.32% and risk of aortic dissection 0.18%). The increase in aortic diameters was associated with increased risk of 0.2% per year (95% confidence interval [CI], 0.03 to 0.5) with diameters less than 40 mm, 0.3% per year (95% CI, 0.1 to 1.4) between 40 and 44 mm, 1.3% per year (95% CI, 0.3 to 4.6) between 45 and 49 mm, and 5.2% per year (95% CI, 0.4 to 12.4) with diameters 50 mm or greater. Fifty-six patients underwent elective surgery with no inhospital mortality. Overall survival at 3, 5, and 10 years was 99% ± 5%, 98.6% ± 6%, and 95.5% ± 2.5%, respectively. CONCLUSIONS: The incidence of aortic events in patients with Marfan syndrome followed at specific units is low, although the risk increases with aortic diameters of 45 mm or greater. These results support current indications, but we consider it reasonable at experienced centers (elective root aortic surgery mortality less than 1%) to indicate an early surgery when the aortic root exceeds 45 mm.


Assuntos
Aneurisma Roto/cirurgia , Aorta Torácica/cirurgia , Aneurisma da Aorta Torácica/cirurgia , Síndrome de Marfan/complicações , Prevenção Secundária/métodos , Procedimentos Cirúrgicos Vasculares/métodos , Adolescente , Adulto , Idoso , Aneurisma Roto/diagnóstico , Aneurisma Roto/etiologia , Aorta Torácica/diagnóstico por imagem , Aneurisma da Aorta Torácica/diagnóstico , Aneurisma da Aorta Torácica/etiologia , Criança , Pré-Escolar , Ecocardiografia , Feminino , Seguimentos , Humanos , Masculino , Síndrome de Marfan/diagnóstico , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Tomografia Computadorizada por Raios X , Adulto Jovem
8.
Symbiosis ; 71(1): 57-63, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28066125

RESUMO

Lichenicolous (lichen-dwelling) fungi have been extensively researched taxonomically over many years, and phylogenetically in recent years, but the biology of the relationship between the invading fungus and the lichen host has received limited attention, as has the effects on the chemistry of the host, being difficult to examine in situ. Raman spectroscopy is an established method for the characterization of chemicals in situ, and this technique is applied to a lichenicolous fungus here for the first time. Xanthoriicola physciae occurs in the apothecia of Xanthoria parietina, producing conidia at the hymenium surface. Raman spectroscopy of apothecial sections revealed that parietin and carotenoids were destroyed in infected apothecia. Those compounds protect healthy tissues of the lichen from extreme insolation and their removal may contribute to the deterioration of the apothecia. Scytonemin was also detected, but was most probably derived from associated cyanobacteria. This work shows that Raman spectroscopy has potential for investigating changes in the chemistry of a lichen by an invading lichenicolous fungus.

9.
Univ. psychol ; 13(3): 1147-1160, jul.-set. 2014.
Artigo em Espanhol | LILACS | ID: lil-745688

RESUMO

En este artículo se realiza una revisión de los principales programas de rehabilitación de las funciones ejecutivas ampliamente reconocidos en la literatura, así como una recopilación de aquellos estudios que han replicado dichos programas en pacientes con daño cerebral adquirido. Estos estudios son seleccionados a través de PubMed al incluir palabras clave tales como: funciones ejecutivas, daño cerebral, evaluación neuropsicológica e intervención. Luego, se analizan a partir de una organización y división de los componentes que trabajan: solución de problemas y memoria de trabajo, autorregulación, motivación e iniciativa y habilidades metacognitivas. Por último se describen aquellos programas que integran más de dos dominios. De la revisión se concluye que existe una gran cantidad de propuestas para la rehabilitación de estas funciones, y queda claro que la rehabilitación de las funciones ejecutivas ofrece efectos positivos sobre el funcionamiento y calidad de vida de la persona, en especial enfocando la intervención a aquellas áreas personales, familiares y ambientales relevantes para su funcionamiento. Sin embargo, aún se carece de suficientes estudios que demuestren la efectividad y eficiencia de dichos programas, lo cual se explica por el uso de muestras pequeñas o de caso único que no permiten la generalización de resultados, las características heterogéneas de los participantes y la baja generalización a la vida cotidiana.


This paper analyses the effectiveness of rehabilitation programs for executive functions in adults with brain damage. We consider an effective treatment when the program shows results with a statistically significant difference in the neuropsychological assessment after intervention (p < 0.05). Moreover, others criteria were considered such as improvement on daily life scales, the transfer of strategies on daily life conditions and the persistence of these for at least six months. The articles were searched through PubMed and must include keys words as: executive functions, brain damage, neuo-psychological assessment and rehabilitation. Then, they were organised according to which were the aim of the treatment: problem-solving and working memory, self-regulation, motivation and initiative and metacognitive skills. Additionally, there is a section where integrative programs were analysed. We concluded that there are many training programs for executive functions with positive results on patients' daily activities when the intervention is focused in metacognitive skills. However, there are still not enough studies that show an accurate effectiveness due to the conceptual complexity of the executive functions, the variability of patients' symptoms and the limited transfer of the knowledge trained to everyday life.


Assuntos
Reabilitação , Neuropsicologia
10.
FEMS Microbiol Ecol ; 89(2): 402-14, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24920320

RESUMO

We have assessed the microbial ecology on the surface of Mittivakkat glacier in SE-Greenland during the exceptional high melting season in July 2012 when the so far most extreme melting rate for the Greenland Ice Sheet has been recorded. By employing a complementary and multi-disciplinary field sampling and analytical approach, we quantified the dramatic changes in the different microbial surface habitats (green snow, red snow, biofilms, grey ice, cryoconite holes). The observed clear change in dominant algal community and their rapidly changing cryo-organic adaptation inventory was linked to the high melting rate. The changes in carbon and nutrient fluxes between different microbial pools (from snow to ice, cryoconite holes and glacial forefronts) revealed that snow and ice algae dominate the net primary production at the onset of melting, and that they have the potential to support the cryoconite hole communities as carbon and nutrient sources. A large proportion of algal cells is retained on the glacial surface and temporal and spatial changes in pigmentation contribute to the darkening of the snow and ice surfaces. This implies that the fast, melt-induced algal growth has a high albedo reduction potential, and this may lead to a positive feedback speeding up melting processes.


Assuntos
Chlamydomonas/metabolismo , Camada de Gelo , Estreptófitas/metabolismo , Biomassa , Ciclo do Carbono , Congelamento , Groenlândia , Fotossíntese , Estações do Ano , Neve , Xantofilas/metabolismo , Zeaxantinas
11.
Life (Basel) ; 3(1): 276-94, 2013 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-25371344

RESUMO

Raman spectroscopy is a valuable analytical technique for the identification of biomolecules and minerals in natural samples, which involves little or minimal sample manipulation. In this paper, we evaluate the advantages and disadvantages of this technique applied to the study of extremophiles. Furthermore, we provide a review of the results published, up to the present point in time, of the bio- and geo-strategies adopted by different types of extremophile colonies of microorganisms. We also show the characteristic Raman signatures for the identification of pigments and minerals, which appear in those complex samples.

12.
Anal Bioanal Chem ; 403(1): 131-44, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22349404

RESUMO

Raman spectroscopy has proven to be a very effective approach for the detection of microorganisms colonising hostile environments on Earth. The ExoMars rover, due for launch in 2018, will carry a Raman laser spectrometer to analyse samples of the martian subsurface collected by the probe's 2-m drill in a search for similar biosignatures. The martian surface is unprotected from the flux of cosmic rays, an ionising radiation field that will degrade organic molecules and so diminish and distort the detectable Raman signature of potential martian microbial life. This study employs Raman spectroscopy to analyse samples of two model organisms, the cyanobacterium Synechocystis sp. PCC 6803 and the extremely radiation resistant polyextremophile Deinococcus radiodurans, that have been exposed to increasing doses of ionising radiation. The three most prominent peaks in the Raman spectra are from cellular carotenoids: deinoxanthin in D. radiodurans and ß-carotene in Synechocystis. The degradative effect of ionising radiation is clearly seen, with significant diminishment of carotenoid spectral peak heights after 15 kGy and complete erasure of Raman biosignatures by 150 kGy of ionising radiation. The Raman signal of carotenoid in D. radiodurans diminishes more rapidly than that of Synechocystis, believed to be due to deinoxanthin acting as a superior scavenger of radiolytically produced reactive oxygen species, and so being destroyed more quickly than the less efficient antioxidant ß-carotene. This study highlights the necessity for further experimental work on the manner and rate of degradation of Raman biosignatures by ionising radiation, as this is of prime importance for the successful detection of microbial life in the martian near subsurface.


Assuntos
Vida , Radiação Ionizante , Análise Espectral Raman/métodos , Deinococcus/isolamento & purificação , Marte , Synechocystis/isolamento & purificação
13.
Anal Bioanal Chem ; 401(9): 2927-33, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21938598

RESUMO

The discovery of small, spherical nodules termed 'blueberries' in Gusev Crater on Mars, by the NASA rover Opportunity has given rise to much debate on account of their interesting and novel morphology. A terrestrial analogue in the form of spherical nodules of similar size and morphology has been analysed using Raman spectroscopy; the mineralogical composition has been determined and evidence found for the biological colonisation of these nodules from the spectral signatures of cyanobacterial protective biochemical residues such as scytonemin, carotenoids, phycocyanins and xanthophylls. This is an important result for the recognition of future sites for the planned astrobiological exploration of planetary surfaces using remote robotic instrumentation in the search for extinct and extant life biosignatures and for the expansion of putative terrestrial Mars analogue geological niches and morphologies.


Assuntos
Cianobactérias/química , Exobiologia , Meio Ambiente Extraterreno/química , Análise Espectral Raman/métodos , Regiões Árticas , Indóis/análise , Indóis/isolamento & purificação , Marte , Fenóis/análise , Fenóis/isolamento & purificação , Ficocianina/análise , Ficocianina/isolamento & purificação , Voo Espacial , Xantofilas/análise , Xantofilas/isolamento & purificação
14.
Ann Thorac Surg ; 90(1): e4-5, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20609735

RESUMO

Arthrographis kalrae is an uncommon etiology in clinical fungal infections. We describe a patient with native aortic valve endocarditis and aortic pseudoaneurysm caused by this agent who required multiple cardiac procedures.


Assuntos
Endocardite/microbiologia , Micoses/complicações , Saccharomycetales/isolamento & purificação , Feminino , Humanos , Pessoa de Meia-Idade
15.
Philos Trans A Math Phys Eng Sci ; 368(1922): 3127-35, 2010 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-20529949

RESUMO

Volcanic eruptions and lava flows comprise one of the most highly stressed terrestrial environments for the survival of biological organisms; the destruction of botanical and biological colonies by molten lava, pyroclastic flows, lahars, poisonous gas emissions and the deposition of highly toxic materials from fumaroles is the normal expectation from such events. However, the role of lichens and cyanobacteria in the earlier colonization of volcanic lava outcrops has now been recognized. In this paper, we build upon earlier Raman spectroscopic studies on extremophilic colonies in old lava flows to assess the potential of finding evidence of biological colonization in more recent lava deposits that would inform, first, the new colonization of these rocks and also provide evidence for the relict presence of biological colonies that existed before the volcanism occurred and were engulfed by the lava. In this research, samples were collected from a recent expedition to the active volcano at Kilauea, Hawaii, which comprises very recent lava flows, active fumaroles and volcanic rocks that had broken through to the ocean and had engulfed a coral reef. The Raman spectra indicated that biological and geobiological signatures could be identified in the presence of geological matrices, which is encouraging for the planned exploration of Mars, where it is believed that there is evidence of an active volcanism that perhaps could have preserved traces of biological activity that once existed on the planet's surface, especially in sites near the old Martian oceans.


Assuntos
Exobiologia , Análise Espectral Raman , Erupções Vulcânicas/análise , Minerais/análise
16.
Astrobiology ; 8(1): 119-56, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18211229

RESUMO

We have investigated how morphological biosignatures (i.e., features related to life) might be identified with an array of viable instruments within the framework of robotic planetary surface operations at Mars. This is the first time such an integrated lab-based study has been conducted that incorporates space-qualified instrumentation designed for combined in situ imaging, analysis, and geotechnics (sampling). Specimens were selected on the basis of feature morphology, scale, and analogy to Mars rocks. Two types of morphological criteria were considered: potential signatures of extinct life (fossilized microbial filaments) and of extant life (crypto-chasmoendolithic microorganisms). The materials originated from a variety of topical martian analogue localities on Earth, including impact craters, high-latitude deserts, and hydrothermal deposits. Our in situ payload included a stereo camera, microscope, Mössbauer spectrometer, and sampling device (all space-qualified units from Beagle 2), and an array of commercial instruments, including a multi-spectral imager, an X-ray spectrometer (calibrated to the Beagle 2 instrument), a micro-Raman spectrometer, and a bespoke (custom-designed) X-ray diffractometer. All experiments were conducted within the engineering constraints of in situ operations to generate realistic data and address the practical challenges of measurement. Our results demonstrate the importance of an integrated approach for this type of work. Each technique made a proportionate contribution to the overall effectiveness of our "pseudopayload" for biogenic assessment of samples yet highlighted a number of limitations of current space instrument technology for in situ astrobiology.


Assuntos
Exobiologia/instrumentação , Sedimentos Geológicos/microbiologia , Marte , América , Regiões Antárticas , Carbonato de Cálcio/química , Sulfato de Cálcio/química , Sedimentos Geológicos/química , Alemanha , Compostos de Ferro/química , Minerais , Origem da Vida
17.
Geochem Trans ; 8: 8, 2007 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-17697380

RESUMO

BACKGROUND: A profile across 8 layers from a fossil travertine terrace from a low temperature geothermal spring located in Svalbard, Norway has been studied using both Raman spectroscopy and SEM (Scanning Electron Microscopy) techniques to identify minerals and organic life signals. RESULTS: Calcite, anatase, quartz, haematite, magnetite and graphite as well as scytonemin, three different carotenoids, chlorophyll and a chlorophyll-like compound were identified as geo- and biosignatures respectively, using 785 and/or 514 nm Raman laser excitation wavelengths. No morphological biosignatures representing remnant microbial signals were detected by high-resolution imaging, although spectral analyses indicated the presence of organics. In contrast, in all layers, Raman spectra identified a series of different organic pigments indicating little to no degradation or change of the organic signatures and thus indicating the preservation of fossil biomarker compounds throughout the life time of the springs despite the lack of remnant morphological indicators. CONCLUSION: With a view towards planetary exploration we discuss the implications of the differences in Raman band intensities observed when spectra were collected with the different laser excitations. We show that these differences, as well as the different detection capability of the 785 and 514 nm laser, could lead to ambiguous compound identification. We show that the identification of bio and geosignatures, as well as fossil organic pigments, using Raman spectroscopy is possible. These results are relevant since both lasers have been considered for miniaturized Raman spectrometers for planetary exploration.

18.
Spectrochim Acta A Mol Biomol Spectrosc ; 68(4): 1133-7, 2007 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17600759

RESUMO

The Rio Tinto site is recognised as a terrestrial Mars analogue because of the presence of jarosite and related sulfates which have recently been identified by the NASA Mars Exploration Rover "Opportunity" in the El Capitan region of Meridiani Planum on Mars. It has long been known that acidophilic microbial action is responsible for the deep blood-red colour of the water in Rio Tinto, where the pH varies from about 1.5 to 3.0 and the water is rich in iron and sulfur. Following recent Raman spectroscopic characterisation of the mineral phases of the Rio Tinto system, we report here a study of the biological components found in several specimens of deposited minerals and near the waterside that were collected during a GeoRaman VI Conference organized field trip in 2006. Key biosignatures were found for carotenoids, scytonemin and mycosporine-like amino acids, which are indicative of the biological colonisation of exposed mineral substrates; information from this study will be useful for targeting Martian sites using a miniaturized Raman instrument where the biosignatures of relict or extant life could remain in the geological record.


Assuntos
Exobiologia , Meio Ambiente Extraterreno , Marte , Minerais/química , Simulação de Ambiente Espacial , Análise Espectral Raman , Espanha
19.
Anal Bioanal Chem ; 388(3): 683-9, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17404715

RESUMO

The mummification ritual in ancient Egypt involved the evisceration of the corpse and its desiccation using natron, a naturally occurring evaporitic mineral deposit from the Wadi Natrun, Egypt. The deposit typically contains sodium carbonate, sodium bicarbonate and impurities of chloride and sulfate as its major elemental components. It is believed that the function of the natron was to rapidly remove the water from the cadaver to prevent microbial attack associated with subsequent biological tissue degradation and putrefaction. Several specimens of natron that were recently collected from the Wadi Natrun contained coloured zones interspersed with the mineral matrix that are superficially reminiscent of extremophilic cyanobacterial colonisation found elsewhere in hot and cold deserts. Raman spectroscopy of these specimens using visible and near-infrared laser excitation has revealed not only the mineral composition of the natron, but also evidence for the presence of cyanobacterial colonies in several coloured zones observed in the mineral matrix. Key Raman biosignatures of carotenoids, scytonemin and chlorophyll have been identified.


Assuntos
Embalsamamento , Sedimentos Geológicos/análise , Múmias , Bicarbonatos/análise , Carbonatos/análise , Cianobactérias/isolamento & purificação , Egito , Embalsamamento/métodos , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Bicarbonato de Sódio/análise , Análise Espectral Raman , Sulfatos/análise
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 68(4): 1143-8, 2007 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17353144

RESUMO

Raman spectra were obtained from the natural crystalline (evenkite) and amorphous (ozokerite and hatchetin) hydrocarbons, originating from volcanic and sedimentary rocks from several sites (Merník, Evenki, Zastávka). Raman spectra of all materials investigated confirm their exclusively aliphatic character. Vibrational assignments are proposed and compared with pure synthetic compounds and the differences in Raman spectra obtained from materials from different sites are discussed. Monoclinic evenkite corresponds to n-tetratracosane (C(24)H(50)). Noncrystalline waxy ozokerite and hatchetine contain several degradation products in addition to higher paraffins.


Assuntos
Parafina/química , Análise Espectral Raman , Ceras/química , Alcanos/química
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