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J C Marques

Publications and source records attributed to J C Marques.

14 recordsLinked to original sources
PubMed2006

Comparative study of the whisky aroma profile based on headspace solid phase microextraction using different fibre coatings.

A dynamic headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to ion trap mass spectrometry (GC-(IT)MS) method was developed and applied for the qualitative determination of the volatile compounds present in commercial whisky samples which alcoholic content was previously adjusted to 13% (v/v). Headspace SPME experimental conditions, such as fibre coating, extraction temperature and extraction time, were optimized in order to improve the extraction process. Five different SPME fibres were used in this study, namely, poly(dimethylsiloxane) (PDMS), poly(acrylate) (PA), Carboxen-poly(dimethylsiloxane) (CAR/PDMS), Carbowax-divinylbenzene (CW/DVB) and Carboxen-poly(dimethylsiloxane)-divinylbenzene (CAR/PDMS/DVB). The best results were obtained using a 75 microm CAR/PDMS fibre during headspace extraction at 40 degrees C with stirring at 750 rpm for 60 min, after saturating the samples with salt. The optimised methodology was then applied to investigate the volatile composition profile of three Scotch whisky samples--Black Label, Ballantines and Highland Clan. Approximately seventy volatile compounds were identified in the these samples, pertaining at several chemical groups, mainly fatty acids ethyl esters, higher alcohols, fatty acids, carbonyl compounds, monoterpenols, C13 norisoprenoids and some volatile phenols. The ethyl esters form an essential group of aroma components in whisky, to which they confer a pleasant aroma, with "fruity" odours. Qualitatively, the isoamyl acetate, with "banana" aroma, was the most interesting. Quantitatively, significant components are ethyl esters of caprilic, capric and lauric acids. The highest concentration of fatty acids, were observed for caprilic and capric acids. From the higher alcohols the fusel oils (3-methylbutan-1-ol and 2.phenyletanol) are the most important ones.

Alcoholic Beverages↗
PubMed2006

Are taxonomic distinctness measures compliant to other ecological indicators in assessing ecological status?

Assessing the ecological status, a concept implemented in the European Water Framework Directive [EC, 2000. Directive of the European Parliament and of the Council 2000/60/EC establishing a framework for community action in the field of water policy PE-CONS 3639/1/00, p. 72], requires the application of methods capable of distinguishing different levels of ecological quality. The Average Taxonomic Distinctness has been used as tool in this context, and we tested the robustness of Taxonomic Distinctness measures applying it in different scenarios (estuarine eutrophication, organic pollution, and re-colonisation after physical disturbance), analysing simultaneously its compliance to other types of ecological indicators. Results show that, in most of the case studies, only Total Taxonomic Distinctness was relatively satisfactory in discriminating between disturbed situations. Other Taxonomic Distinctness measures have not proved to be more sensitive than other ecological indicators (Shannon-Wiener, Margalef, and Eco-Exergy indices). Therefore, this approach does not seem to be particularly helpful in assessing systems' ecological status with regard to the WFD implementation.

Animals↗
PubMed2005

Are taxonomic distinctness measures compliant to other ecological indicators in assessing ecological status?

Assessing the ecological status, a concept implemented in the European Water Framework Directive [Directive of the European Parliament and of the Council 2000/60/EC establishing a framework for community action in the field of water policy PE-CONS 3639/1/00, 72 p.], requires the application of methods capable of distinguishing different levels of ecological quality. Somerfield and Clarke [Marine Environmental Research 43 (2003) 145-156] proposed Average Taxonomic Distinctness to be used as tool in this context. We tested the robustness of Taxonomic Distinctness measures applying it in different scenarios (estuarine eutrophication, organic pollution, and re-colonisation after physical disturbance), analysing simultaneously its compliance to other types of ecological indicators. Results show that, in most of the case studies, only Total Taxonomic Distinctness was relatively satisfactory in discriminating between disturbed situations. Other Taxonomic Distinctness measures have not proved to be more sensitive than other ecological indicators (Shannon-Wiener, Margalef, and Eco-Exergy indices). Therefore, this approach does not seem to be particularly helpful in assessing systems' ecological status with regard to the WFD implementation.

Animals↗
PubMed2003

Heterocyclic acetals in Madeira wines.

The maturation of Madeira wines usually involves exposure to relatively high temperatures which affect the aroma and flavour composition leading to the formation of the typical and characteristic bouquet of these wines. The formation of heterocyclic acetals (1,3-dioxanes and 1,3-dioxolanes) was investigated in order to determine levels and for possible use as indicators of wine age. The results show a linear correlation of the investigated acetals with wine age but suggest that the acetalization reaction is not particularly affected by the drastic oxidative conditions observed during maturation.

Acetals↗
PubMed2001

Diversity, biodiversity, conservation, and sustainability.

The concepts of diversity and biodiversity are analysed regarding their historical emergence, and their intrinsic meaning and differences are discussed. Through a brief synopsis, difficulties usually experienced by statisticians in capturing the dynamics of diversity are analysed and main problems identified. The shift from diversity to the more holistic biodiversity as a working concept is appraised in terms of the novelty involved. Through a number of examples, the way the two concepts capture natural cyclic changes is analysed, and their reciprocal and complementary relations are approached theoretically. The way diversity could develop from the stores of biodiversity as its active expression through selective and evolutionary processes is described. Through the use of a very simple dynamic model, the concepts of diversity and biodiversity are analysed in extremely opposite hypothetical scenarios. Comparisons with natural situations are made and the theoretical implications from the conservation point of view are discussed. These support the opinion that conservation undertaken in restricted and protected areas is not self-sustainable, needing permanent external intervention to regulate internal processes, and in the long run will most probably lead in the direction of obsolescence and extinction. Finally, the relations between diversity, biodiversity, and sustainability are approached. The vagueness of the sustainability concept is discussed. Preservation of biodiversity is then defended as one of the best available indicators to assist us in fixing boundaries which may help to provide a more precise definition of sustainability.

Animals↗
PubMed2000

Surfactant (Genapol OX-80) toxicity to Selenastrum capricornutum.

A non-ionic surfactant (Genapol OX-80) was proposed as a means of reducing destructive crayfish activity in rice. In order to study the toxicity of this product on algae, a test in accordance to the ISO 8692 protocol (1989) was performed. The growth inhibiting effect of the pure formulation of Genapol OX-80 was studied on Selenastrum capricornutum in the concentration range of 0.01-1.0 mg/l. The result indicated a 72 h EC50-value of 0.5 mg/l. The suggested field concentration of approximately 50 mg/l is therefore two orders of magnitude above the algal EC50-value. From our findings it is expected that the impact on the rice field algae will not be negligible.

Agriculture↗
PubMed1997

Qualitative and quantitative high-performance liquid chromatographic analysis of aldehydes in Brazilian sugar cane spirits and other distilled alcoholic beverages.

A study is presented on the high-performance liquid chromatographic analysis of eighteen aldehydes in Brazilian sugar cane spirits and other international brandies. The aldehydes were separated by reversed-phase high-performance liquid chromatography as 2,4-dinitrophenylhydrazones (DNPHs). A very good chromatographic separation was achieved for eighteen different aldehyde-DNPHs. The proposed methodology is quite simple and not very time-consuming. Ten aldehydes were identified in 75 beverages and quantified using the external standard method with UV detection at 365 nm. A detailed knowledge of the aldehyde content should significantly contribute to improving the quality control of distilled spirits.

Alcoholic Beverages↗
PubMed1993

[A pulsed Doppler study of left atrial and ventricular inflow in 2 populations of normotensive and hypertensive subjects].

OBJECTIVE: Comparative analysis of left atrial and left ventricle Doppler inflow patterns in patients with essential systemic mild to moderate hypertension and normal global left ventricular systolic function. PATIENTS: A group of out patients with the diagnosis of hypertension referred to the Echocardiographic Laboratory of Egas Moniz Hospital in Lisbon. SETTING: Echocardiographic Doppler prospective study. MATERIAL AND METHODS: We studied a group of 50 patients with the diagnosis of mild to moderate arterial hypertension (Group H), which was compared with a population of 50 normal subjects (Group N). In each case we analysed the pulsed Doppler flow of the right upper pulmonary vein and the diastolic inflow of the left ventricular cavity. We calculated the peak velocities and time velocity integrals of the systolic, diastolic and atrial contraction waves of the pulmonary venous flow and also the systo-diastolic velocity and time velocity integral ratios. In the transmitral Doppler flow analysis we evaluated the peak velocities and time velocity integrals of the early (E wave) and late (A wave) waves, and their time velocity and velocity ratio. We assessed also the isovolumic relaxation time and left ventricular mass index. RESULTS: In groups N and H the peak velocity of the pulmonary venous flow systolic wave was 0.53 +/- 0.15 cm/sec and 0.75 +/- 0.10 cm/sec (p = 0.01), diastolic wave was 0.50 +/- 0.10 cm/sec and 0.41 +/- 0.09 cm/sec (p = 0.03) and atrial contraction wave was 0.18 +/- 0.03 cm/sec and 0.35 +/- 0.08 (p = 0.001), with a systo-diastolic ratio of 1.06 +/- 0.10 and 1.83 +/- 0.10 (p < 0.001), respectively. In these two groups the time velocity integral of the pulmonary venous flow systolic wave was 14.4 +/- 2.6 cm and 17.8 +/- 1.8 cm (p = 0.001), the diastolic wave was 12.5 +/- 3.2 cm and 9.3 +/- 1.3 cm (p = 0.05) and the atrial contraction wave was 4.4 +/- 0.07 cm (p = 0.001), with a systo-diastolic ratio of 1.1 +/- 0.16 and 1.9 +/- 0.12 (p < 0.001), respectively. For the group H and considering the three subgroups, hypertensive patients without anatomical or functional alterations, with isolated diastolic dysfunction and with left ventricular hypertrophy associated to diastolic dysfunction, the velocity systo-diastolic ratio was 1.08 +/- 0.12, 1.57 +/- 0.08 (p < 0.01) and 2.4 +/- 0.08 (p < 0.01) and 2.4 +/- 0.08 (p < 0.001), the systo-diastolic time velocity integral ratio was 1.22 +/- 0.17, 1.72 +/- 0.13 (p < 0.01) and 2.4 +/- 0.15 (p < 0.001), the peak velocity of the atrial contraction wave was 0.28 +/- 0.07, 0.3 +/- 0.08 (p < 0.01) and 0.43 +/- 0.07 (p < 0.001) and its time velocity integral was 4.6 +/- 0.06 cm, 5.6 +/- 0.07 cm (p < 0.01) and 7.0 +/- 0.08 cm (p < 0.001). CONCLUSIONS: Pulsed Doppler study of pulmonary venous flow is significantly abnormal in patients with arterial hypertension. This abnormal pulmonary venous flow pattern has a close relationship with structural and functional alterations of the left ventricle. Combined analysis of the pulsed Doppler inflow at these two cardiac anatomical levels is fundamental to understand the pathophysiology of hypertensive heart disease.

Adult↗
PubMed1991

[Significance of the unexpected hypertensive response to exertion. Correlation with ambulatory blood pressure monitoring and echocardiography].

The aim of this study was to analyse the meaning of unexpected hypertensive response during treadmill stress test in resting normotensive individuals without any evidence of cardiovascular pathology. The study group of 52 persons who fulfil the inclusion criteria was compared with a homogenous control population composed by 200 individuals with a suitable blood pressure response to stress. The adopted criteria for hypertensive response were the presence of blood pressure greater than or equal to 180/100 mmHg after 6 stress, in maximal stress greater than or equal to 210/110 mmHg and after 5' recovering greater than or equal to 150/90 mmHg. 74% of patients with hypertensive response appeared to be hypertensive according to the criteria of ambulatory blood pressure monitoring--day blood pressure greater than or equal to 140/90 mmHg and night blood pressure greater than or equal to 120/80 mmHg. After echocardiographic study to define the index of left ventricular mass, 68% of individuals with hypertensive stress response showed left ventricular hypertrophy with a medium index of 145 + 17 g/m2 (P less than or equal to 0.01) in most cases with a concentrical hypertrophy type. The appearance of tensional response of hypertensive type ascertains the probability of hypertensive disease. The analysis of tensional response to stress is an integrant part of a methodology of approaching patients suspect of high blood pressure.

Adult↗
PubMedDate not supplied

[Complete auriculo-ventricular block during therapy with carbamazepine].

The authors describe the case of a complete AV block probably induced by carbamazepine. They also review cases described in the literature and suggest some preventive measures before beginning therapy with carbamazepine, mainly in patients over sixty-five years of age, with or without known cardiovascular pathology.

Aged↗
PubMedDate not supplied

[The indices of pressure variability by noninvasive ambulatory monitoring of the arterial pressure. A study in 2 normotensive and hypertensive populations].

OBJECTIVE: Analysis of different indices of blood pressure (BP) variability using the ambulatory blood pressure monitoring (ABPM) method in two populations of hypertensive patients (HTA Group) and normotensive volunteers (NOR Group). SETTING: Noninvasive prospective ambulatory study to assess the alterations of the circadian blood pressure profile through ABPM indices of blood pressure variability. PATIENTS: Patients with the diagnosis of essential arterial hypertension referred for clinical investigation to the Cardiology Department of Egas Moniz Hospital in Lisbon. MATERIAL AND METHODS: 40 hypertensive patients (HTA Group) and 30 normal subjects (NOR Group) were included in this study. We calculated the short and long term variability indices. The short term variability indices were the casual and mean immediate BP deviation, percentage of BP peaks and BP peak relative deviation and maximal range variation. Some clinical and general factors considered were namely age, gender, height, weight, body area and index, mean and casual systolic-diastolic blood pressure. RESULTS: Concerning systolic blood pressure in hypertension Vs normal groups respectively, the casual BP deviation was 15 +/- 4 mmHg and 7 +/- 4 mmHg (p 0.003), the mean immediate BP deviation was 18.5 +/- 4 mmHg and 7.5 +/- 3 mmHg (p 0.002), the percentage of BP peaks was 27 +/- 6% (p < 0.001), the percentage of BP peak area was 29 +/- 7% and 6 +/- 3% (p 0.001) and the percentage of relative deviation was 14 +/- 4% and 8 +/- 3% (p 0.03). For diastolic blood pressure all differences were not statistically significant between the two groups and the same happened for systolic blood pressure in relation to standard deviation and maximal range variation. Among these parameters and general and clinical characteristics, the systolic mean and casual blood pressure level showed an acceptable correlation with mean immediate deviation (R = 0.54/0.49), percentage of BP peaks (R = 0.56/0.49) and percentage of BP peak area (R = 0.60/0.53). CONCLUSIONS: Blood pressure variability can be adequately evaluated through the method of ambulatory blood pressure monitoring. Some variability indices can be extracted from the 24 hour curves of ambulatory blood pressure monitoring. Long-term variability indices are not related to the level of blood pressure. In the hypertension group we found a greater variability concerning short term indices, namely immediate deviation, percentage and are of peak curve.

Adult↗
PubMedDate not supplied

[A double ambulatory product (blood pressure and heart rate), mild arterial hypertension and left ventricular hypertrophy].

OBJECTIVE: Analysis of the different ambulatory blood pressure monitoring derived parameters in terms of cardiac structural repercussion, in patients with isolated systolic and mild systolic-diastolic hypertension. SETTING: Prospective study involving simultaneously the two-dimensional echocardiographic technique and the ambulatory blood pressure monitoring method. PATIENTS: Out patients regularly observed in the Cardiology Department of Egas Moniz Hospital in Lisbon, were included in our study. MATERIAL AND METHODS: We studied 50 hypertensive patients who fulfilled the inclusion criteria of our study (Group H) and 20 subjects who were the normal aged matched population (Group N). through ambulatory blood pressure monitoring, in each individual of these two groups, we considered the mean values of daily systolic blood and diastolic blood pressure, heart rate and ambulatory heart rate blood pressure product. Through two-dimensional echocardiography we calculated the left ventricular mass and the correspondent index corrected for the body surface. RESULTS: In the H group an comparing to the N group, the mean value of the daily systolic blood pressure was 112 +/- 6 mmHg and 159 +/- 8 mmHg (p < 0.001) respectively, diastolic blood pressure was 60 +/- 5 mmHg and 75 +/- 7 mmHg respectively (p < 0.001), heart rate blood pressure product was 6720 +/- 580 and 12561 +/- 678 (p < 0.0001) and of the left ventricular mass index was 109 +/- 10 gm2 and 145 +/- 7 g/m2 (p < 0.001). The correlation coefficient between the left ventricular mass index and mean systolic, diastolic blood pressures and ambulatory heart rate blood pressure product was 0.60 (p < 0.01), 0.45 (p = NS) and 0.73 (p < 0.001) respectively. CONCLUSIONS: In the evaluation of the increase in left ventricular mass, ambulatory heart rate blood pressure product is a more accurate parameter compared to the mean daily blood pressure values. Ambulatory blood pressure monitoring is a method with a great potential and clinical application, when studying patients with hypertension diagnosis.

Adult↗