[en] The analyses of biological parameters in river ecosystems have been traditionally used as indicative of water quality with the advantage over chemical or physical analyses that they integrate the effects of punctual as well as long term effects. However, analyses of biological parameters (such as biomass and metabolism) performed at different spatial scales (from the microbial communities to the whole river) inform about different key processes. At the finer scale, microbial interactions and the structure of the microbial community (biofilm microbial biomass, three dimensional structure, and relevance of polysaccharide matrix) can be detected. At the reach scale, the different stream bed substrate (sediment, rocks, and particulate organic matter accumulation) are shown to play differential and specific roles on the processing of organic and inorganic materials in the flowing water. (Author)

[en] At the present, Peru has an installed electricity capacity of 4112 MW from which the 80% comes from hydroelectric sources and other 20% from thermal sources. Lima city concentrates the larger industrial activities and uses 95% of the hydro-electric supply the 5% comes from thermal origin. This situation provokes an energetic vulnerability to Lima, a city with more them 10 million of inhabitants, because climatic changes and the electric towers destruction. In the 1989-1992 period lack of energy meant economic losses for about US$ 2 100 000. To solve this problem the government is building a 300 MW thermal station. This alternative means a low investment for Kw installed but high production costs. Additionally the installation of the plant in Lima will increase the environmental contamination due to emission of about 20000 TM/year of SOx and 7500 TM/year of NOx. The research study recommends as a solution the diversification of energy sources, avoiding dependence of the hydro-electrical ones. In the same form it suggests that the next 300 MW power station to be installed for about 1998 would be a nuclear power plant but not thermal one. It also makes a revision of the new designs for nuclear power plants called safe inherently which design and construction philosophy avoid the possibility of accidents like Chernobyl. (author). 15 refs., 5 tabs., 13 figs

[en] In this work, it has been studied the radiology risk of the reactor RP-0 in two specific cases: during a normal operation and an accidental case. The calculus of the risk during the normal operation reach to the 1,05μSv/h. The calculus of doses for accidental cases under an assumption of the critical of 5 x 10⁺¹⁷ fissions without fracture of clad of the fuel element is between 43 Sv (in the control room) to 35μSv in the population beside the reactor. Also, under an assumption of prompt critical with fracture of casing and with a emission of the 1% of the radioactive inventory to the environment; this study concludes that population near to the Center (200 m) would receive a dose to the whole body 34μSv, thyroid: 0,96 mSv. (author) 4 refs

[en] Full text: The spices Turmeric (curcuma longa) and Saffron (crocus sativus) have also been used as pigments. The EPR spectrum of each shows a readily detectable free radical signal. EPR spectra of the available pure chief active colorants in solid form also give free radical signals. Curcumin (turmeric) is a 'linear' symmetric phenolic, so is expected to do so. The peptide turmerin (commercially unavailable), containing sulphur, may also contribute to the ESR signal. Crocetin (saffron) is a 'linear' molecule, related to the beta-carotenes, which do not give free radical signals: but it does, presumably because of its particular resonant structure properties

[en] Full text: Olives and extra virgin olive oil, are known to be very rich in antioxidants, most of which are phenolics, such as oleuropein, a derivative of catechol: the 'catechol' ring is separated, and effectively isolated electrically from the other (6-sided) ring. The main anthocyanin in olives in keracyanin (cyanidin-3-0-rutinoside). Solid samples of these two phenolics, and of catechol, were examined by ESR using a Varian E-12 spectrometer (x-band: ∼9.1 GHz) at room temperature. All three samples gave single unstructured lines of ∼ 10g. width with g-vales close to 2. The presence of these free radical signal shows the antioxidant action of these phenolics, even in the solid state. We believe this is first observation of free radicals in olive phenolics

[en] Full text: Polyphenols are widespread in vegetables and fruits and they play an important role in human diet and health: these compounds act mainly as antioxidants and radical scavengers. In this work we have detected free radicals in the following natural polyphenols: Endotelon, an anthocyanic grapeskin extract; malvidin 3,5-O-diglucosides (malvin); oleuropein, an olive polyphenol; a commercial green tea extract, and pure epigallocatechingallate EGCG. The investigation was performed using a Varian E-12 ESR Spectrometer (∼9.1 GHz) at room temperature. All except the green tea extract gave single unstructured lines of ∼ 10 gauss linewidth. The tea extract signal showed 3 lines, one ∼ 20 gauss wide, one ∼ 10 gauss wide, and one ∼ 2-3 gauss wide. Saturation behaviour of these lines at room and liquid N₂ temperature showed them to be from different radicals About 50% of the extract is represented by epigallocatechingallate (EGCG). Using the pure sample EGCG it was possible to assign the appropriate radical, which corresponded with the broadest and strongest 'single' signal (∼20g wide). The presence of the free radicals in the solid extracts shows that the appropriate molecules can act as radical scavengers by forming stable radicals

[en] Full text: A solid extract of procyanidins from green tea was studied by ESR, using a Varian E-12 (X-band: ∼9.1 GHz) spectrometer, at room temperature, and liquid N₂ temperature. The spectrum consisted of three unstructured lines, one ∼20 gauss wide, one ∼ 10 gauss wide, and one ∼3 gauss wide. Saturation behaviour of these lines at room and liquid N₂ temperature showed them to be from different radicals. About 50% of the extract is epogallocatechin gallate (EGCG). Using a pure sample of EGCG, it was possible to assign the broadest and strongest 'single' signal to EGCG. It has not been possible yet to assign the other lines to other molecular species

[en] Full text: Trinovin is an extract of red clover, recently released on the dietary supplement market. It is recommended for 'Men's Health', because it contains the phenolics (isoflavones) genistein, biochanin, daidzein and formononetin, said to act as 'phytoestrogens', and is therefore a possible help in prostate gland problems. An Electron Spin Resonance (ESR) study (∼9.1Ghz, room temperature) revealed at least 3 different free radical lines, one with hyperfine structure, consistent with the listed molecules. Accordingly, HPLC/DAD (High Performance Liquid Chromatography/Diode Array Detector) and HPLC/Mass Spectroscopy analyses were performed in order to evaluate the quali-quantitative contents of flavonoidic compounds. The HPLC profile shows two main isoflavones and another three compounds, one of them being a quercetin glycoside. The quercetin glycosides are flavonoidic derivatives abundant in plant materials and present in wine. We can therefore say: even if the phytoestrogen properties claimed for Trinovin turn out to be less than hoped for, the antioxidants contained are very powerful, and so possibly helpful in protection against many diseases, including cancers, atherosclerosis, diabetic retinal bleeding, and non-alcoholic dementia

[en] This paper presents the preliminary results of an investigation on medieval ceramics from Apricena using thermoluminescence (TL), optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray microanalysis (EDS). The combination of physical and chemical-mineralogical analyses has lead to an authentication and an initial characterisation of the ceramic sherds. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

[en] A photochemical and photophysical investigation has been carried out on 2,2-dimethyl-7,8-benzo-2H-chromene and 2,2-dimethyl-5,6-benzo-2H-chromene. Absolute quantum yields of fluorescence [Φ _F(n)] and photochemistry [Φ _PC(n)] have been determined and are functions of the individual states, modes, and vibrational levels (n) excited and thus, there are many quantum yields of each of the foregoing processes. We have found that photochemistry and vibrational relaxation (non-radiative decay) are competitive processes at each vibrational level of each mode of all states. Using photochemistry as a probe, we have determined: (1) the pathways of vibrational relaxation and photochemical processes and have quantitatively evaluated the competitive nature of these; (2) that vibrational relaxation only occurs within the mode excited, there is no crossing between different modes during relaxation; (3) significant radiationless relaxation occurs directly between any pure excited state, S _m(0), and the ground state; (4) the photochemical yield is largely determined by the mode excited, not the energy of excitation