3,134 publications from this institution
Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular mass, have been classified as probably being carcinogenic to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention the European Union is paying to regulating their maximum allowed levels in various types of foodstuffs. Like tobacco and smoked meats, alcoholic drinks can also contain these carcinogenic chemicals, as the latter have been detected in the charred insides of barrels, some ingredients such as caramel or the smoke released during the drying of germinated barley in beer or whisky. This paper determined the contents of seven PAHs in alcoholic beverages of variable alcoholic strength that had been aged in charred barrels for different times (months, years). The aim was to elucidate the dependence of the formation of seven PAHs on the type of charring (traditional or convective) used and the charring intensity (light, medium or heavy). Based on the results, the way the tree raw material is toasted strongly influences PAH levels in alcoholic drinks; thus, traditional charring produces increased amounts of PAHs from the wood relative to convective toasting. The sum of the analysed PAH concentrations in the aged alcoholic beverages studied ranged from zero for a white wine to 172 ng l(-1) for a 'brandy de jerez solera'. The carcinogenic indicator benzo[a]pyrene was found at concentrations below 10 ng l(-1). These PAH concentrations in alcoholic beverages are very low relative to those in smoked and char-broiled foodstuffs. Any health hazards, however, can be minimized by using convective toasting to manufacture the barrels where the drinks are to be aged.
Abstract Diagnosis of hypertension—elevated blood pressure (BP) associated with increased cardiovascular disease (CVD) risk—and its management for decades have been based primarily on single time‐of‐day office BP measurements (OBPM) assumed representative of systolic (SBP) and diastolic BP (DBP) during the entire 24‐hours span. Around‐the‐clock ambulatory blood pressure monitoring (ABPM), however, reveals BP undergoes 24‐hours patterning characterized in normotensives and uncomplicated hypertensives by striking morning‐time rise, 2 daytime peaks—one ~2‐3 hours after awakening and the other early evening, small midafternoon nadir and 10‐20% decline (BP dipping) in the asleep BP mean relative to the wake‐time BP mean. A growing number of outcome trials substantiate correlation between BP and target organ damage, vascular and other risks is greater for the ABPM‐derived asleep BP mean, independent and stronger predictor of CVD risk, than daytime OBPM or ABPM‐derived awake BP. Additionally, bedtime hypertension chronotherapy, that is, ingestion of ≥1 conventional hypertension medications at bedtime to achieve efficient attenuation of asleep BP, better reduces total CVD events by 61% and major events (CVD death, myocardial infarction, ischaemic and haemorrhagic stroke) by 67%—even in more vulnerable chronic kidney disease, diabetes and resistant hypertension patients—than customary on‐awaking therapy that targets wake‐time BP. Such findings of around‐the‐clock ABPM and bedtime hypertension outcome trials, consistently indicating greater importance of asleep BP than daytime OBPM or ambulatory awake BP, call for a new definition of true arterial hypertension plus modern approaches for its diagnosis and management.
A detailed high-resolution electron microscopy study of the formation of Ag nanowires by solvent reduction in N,N-dimethylformamide (DMF), in the presence of poly(vinylpyrrolidone) (PVP) at high temperature provided clear evidence that the nanowires grow through the oriented aggregation of precursor nanoparticles. The HRTEM images demonstrate that initially, icosahedral and cuboctahedral Ag nanoparticles are formed, which then self-assemble to form aligned stripes, and eventually fuse with each other to yield single crystalline nanowires. The nanoparticle aggregation only takes place through preferred facets of the original nanocrystals, and therefore intermediate twisted wires are observed.
Abstract A method for determination of biphenyl residues In whole citrus fruit Is described. The mascerated fruit was distilled In an acid medium, the distillate was extracted with cyclohexane, and biphenyl was determined In the extract using various measures obtained by first and second derivative Infrared (IR) spectrophotometry. Calculations were performed by PE680 and SNGLE programs on data obtained using a Perkln- Elmer Model 3600 data station. The relative precision of the determinations at 70 ppm was 1.8 to 2.0%; the detection limit was 5 ppm In all measurements, and recovery of spiking concentrations of 20 to 80 ppm ranged from 90.2 ± 5.5 % (for the amplitude of the 739 cm-1 peak of the first derivative) to 97.5 db 2.0% (for the trough-to-peak difference from the 737 cm-1 minimum to the 743 cm-1 maximum of the second derivative).
