3,181 research outputs found

    Recent Highlights in Green Oxidative Chemical Processes Applied to Steroid Chemistry

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    Steroids and their oxidation products are widely distributed in living organisms and are important intermediates for the synthesis of many biologically active molecules. Due to their pharmacological and synthetic relevance, several oxidative chemical processes for the functionalization of the steroid nucleus have been developed. Green chemistry principles have been incorporated in some oxidative transformations of steroids, allowing significant advances in synthetic chemistry applied to these compounds. This chapter presents a selection of relevant applications of pharmaceutical green chemistry to steroid’s oxidative processes. Special emphasis is given to catalytic processes encompassing heterogeneous nanocatalysts, whose application in this context is increasing over the past years. This chapter is organized according to the reaction type that includes alcohol oxidation, epoxidation of alkenes, and allylic oxidation of alkenes to enones, among other relevant oxidative transformations. Biocatalytic oxidative methods applied to steroid synthesis are not included in this review

    6β-Acetamido-5α-hydroxy­cholestan-3β-yl acetate

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    The title steroid, C31H53NO4, was prepared from the corresponding 5α,6α-epoxy­cholestane. The conformation of the six-membered rings is close to a chair form, while the five-membered ring adopts a twist conformation. The hydroxyl and acetamide groups are in axial positions. The nucleophilic species bound to the steroid nucleus at position 6 by the β-face, whereas the hydroxyl group at position 5 has α-orientation. All rings are trans-fused. The crystal packing shows that the mol­ecules related by twofold symmetry exist as O—H⋯O hydrogen-bonded dimers

    Flexural and shear strengthening of reinforced concrete beams with a hybrid CFRP solution

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    An experimental program was carried out for assessing the performance of a hybrid solution composed by CFRP systems for the simultaneous flexural and shear strengthening of RC beams. CFRP laminates, applied according to NSM technique, are used for the flexural strengthening, while U‐shape CFRP discrete strips of wet lay‐up sheet, applied according to the EBR technique, are adopted for the shear strengthening. An anchorage system was applied at the extremities of these CFRP strips in an attempt of avoiding their premature debonding. The experimental results showed the hybrid strengthening solution is very effective, not only in terms of increasing the load carrying capacity of the beams, but also in assuring higher mobilization of the tensile capacity of the CFRP. The performance of the hybrid CFRP configuration that included the anchorage system for the shear strengthening was significantly higher than the one assured by other shear strengthening solutions that were applied in similar RC beams and tested until failure using the same test system adopted in this experimental program. The predictive performance of the ACI formulations proposed for estimating the contribution of CFRP systems for the flexural and shear resistance of RC beams was appraised considering the obtained experimental results.This work was supported by FEDER funds through the Operational Program for Competitiveness Factors ‐ COMPETE and National Funds through FCT ‐ Portuguese Foundation for Science and Technology under the project Spaflamis POCI‐01‐0145‐FEDER‐030956. The authors also acknowledges the support provided by the S&P® and “Empreiteiros Casais”

    Exercise echocardiography for the assessment of pulmonary hypertension in systemic sclerosis: a systematic review

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    BACKGROUND: Pulmonary arterial hypertension (PAH) complicates the course of systemic sclerosis (SSc) and is associated with poor prognosis. The elevation of systolic pulmonary arterial pressure (sPAP) during exercise in patients with SSc with normal resting haemodynamics may anticipate the development of PAH. Exercise echocardiography (ExEcho) has been proposed as a useful technique to identify exercise-induced increases in sPAP, but it is unclear how to clinically interpret these findings. In this systematic review, we summarize the available evidence on the role of exercise echocardiography to estimate exercise-induced elevations in pulmonary and left heart filling pressures in patients with systemic sclerosis. METHODS: We conducted a systematic review of the literature using MEDLINE, Cochrane Library and Web of Knowledge, using the vocabulary terms: ('systemic sclerosis' OR 'scleroderma') AND ('exercise echocardiography') AND ('pulmonary hypertension'). Studies including patients with SSc without a prior diagnosis of PAH, and subjected to exercise echocardiography were included. All searches were limited to English and were augmented by review of bibliographic references from the included studies. The quality of evidence was assessed by the Effective Public Health Practice Project system. RESULTS: We identified 15 studies enrolling 1242 patients, who were mostly middle-aged and female. Several exercise methods were used (cycloergometer, treadmill and Master's two step), with different protocols and positions (supine, semi-supine, upright); definition of a positive test also varied widely. Resting estimated sPAP levels varied from 18 to 35 mm Hg, all in the normal range. The weighted means for estimated sPAP were 22.2 ± 2.9 mmHg at rest and 43.0 ± 4.3 mmHg on exercise; more than half of the studies reported mean exercise sPAP ≥40 mmHg. The assessment of left ventricular diastolic function on peak exercise was reported in a minority of studies; however, when assessed, surrogate variables of left ventricular (LV) diastolic dysfunction were associated with higher sPAP on exercise. CONCLUSIONS: We found very high heterogeneity in the methods, the protocols and the estimated sPAP response to exercise. LV diastolic dysfunction was common and was associated with greater elevation of sPAP on exercise.info:eu-repo/semantics/publishedVersio

    Sensory evaluation of cakes prepared with orange-fleshed sweet potato flour (Ipomoeas batatas L.).

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    To assess students´ acceptability and preference for cakes prepared with orange-fleshed sweet potato flour (Ipomoea batatas L.). Materials and methods: the cakes were prepared with wheat flour (sample A) and a mixture where 40% of the wheat flour was replaced by orange-fleshed sweet potato flour (sample B). Questionnaires were applied to 100 students between 10 and 12 years old from a public school in the city of Rio de Janeiro; sensory acceptance and preference tests were also applied. Results: participants were on average 11,7 years old, 80% were 6th graders, 50% were female and 97% of the students reported liking the cakes. In this group, 14% reported consuming cakes less than once a month; 27%, 1-3 times per month; 37%, 1-4 times per week; 19%, 1-2 times a day; and only 2% reported never consuming them. Both cakes had high acceptability; with an average score of 9,27 (A) and 9,26 (B) out of a maximum of 10, without any significant differences in preference. Cake consumption was part of the children?s eating habits. Conclusions: cakes prepared with 40% sweet potato flour were as well accepted as conventional cakes. Further, a portion of this cake (60 g) can contribute up to 22% of daily vitamin A needs

    Exercise-induced pulmonary hypertension in scleroderma patients: a common finding but with elusive pathophysiology

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    BACKGROUND: The etiology of exercise-induced pulmonary hypertension (exPH) in systemic sclerosis (SSc) remains a complex task, as both left ventricle (LV) diastolic dysfunction and pulmonary vascular disease can contribute to its development. We determined the incidence of exPH in SSc and examined the association between pulmonary artery systolic pressure (PASP) and tissue Doppler-derived indexes of pulmonary capillary wedge pressure (PCWP). METHODS: Thirty-eight patients with SSc were studied, using a cycloergometer protocol; 10 were excluded due to resting PH or absence of tricuspid regurgitation (TR); TR and mitral E-wave velocities, LV outflow tract time-velocity integral and LV septal E'-wave were measured before and in peak exercise to calculate cardiac output (CO), PCWP and pulmonary vascular resistance (PVR). RESULTS: Mean age of diagnosis was 57.9 ± 8.9 years. At a mean workload of 64 ± 29 Watts, 48% of patients increased PASP ≥ 50 mmHg. PCWP, assessed by the E/e' ratio, did not change significantly during exercise (10.2 ± 3.1-10.0 ± 5.1; P = NS). Only 3 patients had elevations of the E/e' ratio ≥ 13 during exercise; 2 of them had an exercise PASP ≥ 50 mmHg, yielding a proportion of exPH due to elevated LV filling pressures of 2/11 (18%). Patients with exPH had lower DLCO and had more frequently the diffuse SSc. CONCLUSION: The elevation of PASP during exercise in most patients of this cohort seems to be related to a reduced pulmonary vascular reserve, and not to an increase in PCWP. Further studies are warranted to determine the therapeutic, as well as prognostic implications of these findings.info:eu-repo/semantics/publishedVersio

    Avaliação de minerais em feijão (Phaseolus vulgaris, L.) submetido a diferentes tratamentos de hidratação - secagem.

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    O objetivo do presente trabalho é avaliar os teores dos minerais, ferro, zinco, cálcio e manganês em grãos de feijão biofortificados descascados após diferentes tratamentos de hidratação-secagem
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