Influence of different drying methods on tbe rheological properties of raisins

The rheological parameters of raisins were obtained after three different drying methods: convective, osmo-convective and solar drying. Compression tests were applied to rehydrated samples by using a Texture Analyzer TAXT2i. A mathematical trick was used to determine the stress and area was calculated along the deformation. A power law model could adequately fit stress-true strain curves and parameters; K (measure of stiffness) and n (solid behavior index) were obtained as a function of water activity between 0.755 to 0.432. Results showed that these parameters were strongly dependent on water activity for all drying methods. The constant K, which indicates the resistance against deformation, increased with decreasing water activity. on the other hand, increasing water activity resulted in higher solid behavior indexes, showing a large deviation from the Hookean behavior.

Removal of radionuclides from acid mine waters by retention on adsorbing materials

This study proposes a method for decontamination of acid drainage water from a uranium mine, as an alternative process to lime treatment. The research embodied the recovery of uranium with an ion-exchange resin, treatment of effluent resin with lime, or with inorganic adsorbents and biosorbents. The uranium decontamination level using the resin process was 94% and allowed the recovery of this element as a commercial product. Among the inorganic adsorbents studied, phosphogypsum was effective for Ra-226, Ra-228, and Pb-210 removal. Among the biosorbents, Sargassum sp.was superior in relation to its specific capacity to accumulate and remove Ra-226.

Luminescence of Eu(III) beta-diketone complex supported on functionalized macroporous silica matrix

This work reports on the photoluminescent properties of the complex diequatris(thenoyltrifluoroacetonate) europium(III), which was adsorbed or supported on tubes of modified surface silica matrix. The luminescence data and the experimental intensity parameter results evidence the existence of high interactions between the complex [Eu(tta)(3)(H2O)(2)] and the modified surface matrix. The anchored complex on macroporous silica shows higher intensity parameter values suggesting that the Eu-0 bond becomes more covalent than the adsorbed one. Therefore, the hypersensitive character of the D-5(0) --> F-7(2) transition increases evidencing a high contribution of the dynamic coupling mechanism possibly due to highly polarizable chemical environments occupied by europium(III) ion. The lifetimes of the complex on silica matrices were measured. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Efeitos da deficiência de cálcio e/ou boro sobre o pedúnculo do capítulo do girassol

Foi conduzido, em casa de vegetação, um experimento em solução nutritiva de Steimberg modificada, cultivando-se o girassol (Helianthus annuus L.), cv. Anhandy, com cinco níveis de cálcio e cinco de boro combinados, em esquema fatorial completo 5 x 5, visando-se induzir sintomas tardios, no início do florescimento, de deficiência desses elementos. A deficiência isolada de cálcio induziu o sintoma de colapso do capítulo quando o nível inicial de cálcio na solução foi tal (15,24 ppm de Ca) que permitiu a manifestação do sintoma no início do florescimento. A deficiência de boro manifestou-se antes do florescimento, para todos os níveis iniciais do micronutriente em solução, e isto impediu sua avaliação, em relação ao capítulo.

Temperature investigation of infrared-to-visible frequency upconversion in erbium-doped tellurite glasses excited at 1540 nm

Temperature investigation of infrared-to-visible frequency upconversion in erbium-doped tellurite glasses excited by CW laser radiation at 1540 nm and under cryogenic temperatures is reported. Intense upconversion emission signals around 530, 550 and 660 nm corresponding to the H-2(11/2), S-4(3/2), and F-4(9/2) transitions to the I-4(15/2) ground state were generated and studied as a function of the laser intensity and temperature. The upconversion excitation mechanism of the Er3+ ions emitting energy levels was accomplished via stepwise multiphoton absorption. The green upconversion luminescence exhibited a fivefold intensity enhancement when the temperature of the sample was varied in the range between 5 and 300 K. A maximum green upconversion intensity was attained around 120 K and a steady decreasing behavior for higher temperatures up to 300 K was observed. A model based upon conventional rate equations was used to model the observed temperature evolution of the upconversion luminescence. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Postsurgical stability of oropharyngeal airway changes following counter-clockwise maxillo-mandibular advancement surgery

Purpose: This study evaluated oropharyngeal airway changes and stability following surgical counter-clockwise rotation and advancement of the maxillo-mandibular complex.Methods and Patients: Fifty-six adults (48 females, 8 males), between 15 and 51 years of age, were treated with Le Fort I osteotomies and bilateral mandibular ramus sagittal split osteotomies to advance the maxillo-mandibular complex with a counter-clockwise rotation. The average postsurgical follow-up was 34 months. Each patient's lateral cephalograms were traced, digitized twice, and averaged to estimate Surgical changes (T2-T1) and Postsurgical changes (T3-T2).Results: During surgery, the occlusal plane angle decreased significantly (8.6 +/- 5.8 degrees) and the maxillo-mandibular complex advanced and rotated counter-clock-wise. The maxilla moved forward (2.4 +/- 2.7 mm) at ANS and the mandible was advanced 13.1 +/- 5.1 min at menton, 10 +/- 4.4 mm at point B, and 6.9 +/- 3.7 mm at lower incisor edge. Postsurgical hard tissue changes were not statistically significant. While the upper oropharyngeal airway decreased significantly (4.2 +/- 3.4 min) immediately after surgery, the narrowest retropalatal, lowest retropalatal airway, and the narrowest retroglossal airway measurements increased 2.9 +/- 2.7, 3.7 +/- 3.2, and 4.4 +/- 4.4 mm, respectively. Over the average 34 months Postsurgical period, upper retropalatal airway increased 3.9 +/- 3.7 mm, while narrowest retropalatal, lowest retropalatal airway, and narrowest retroglossal airway remained stable. Head posture showed flexure immediately after Surgery (4.8 +/- 5.9 degrees) and extension postsurgically (1.6 +/- 5.6 degrees).Conclusion: Maxillo-mandibular advancement with counter-clockwise rotation produces immediate increases in middle and lower oropharyngeal airway dimensions, which were constrained by changes in head posture but remain stable over the postsurgical period. The upper oropharyngeal airway space increased only on the longest follow-up. (C) 2006 American Association of Oral and Maxillofacial Surgeons.

The relationship between differential equations with piecewise constant argument and the associated discrete equations, via dichotomic maps

Dichotomic maps are considered by means of the stability and asymptotic stability of the null solution of a class of differential equations with argument [t] via associated discrete equations, where [.] designates the greatest integer function.

Chronopotentiometric stripping analysis using gold electrodes, an efficient technique for mercury quantification in natural waters

This paper proposes a simple methodology for mercury quantification in natural water by stripping chronopotentiometry at constant current, using gold (film) electrodes constructed from recordable CDs in stationary cell. The proposed method allows the direct measurement of labile mercury in natural waters. To quantify total mercury, a robust and low cost UV irradiation system was developed for the degradation of organic constituents of water. The proposed system presents such advantages as excellent sensitivity, low cost, versatility, and smaller dimensions (portability for on-field applications) when compared with other techniques (ICP, GFAAS, fluorimetry) traditionally utilized for mercury quantification. A large linear region of responses was observed, situated over the range 0.02 - 200 μ g L-1. Various experimental parameters were optimized and the system allowed quantifications in natural samples, with detection limit of 8 ng L-1 and excellent reproducibility (RSD of 1.4% for 48 repetitive measurements using a 10 μ g L-1 mercury solution). Different metal ions were evaluated, including copper, as possible interferences on stripping mercury signals. Applications of the new method were demonstrated for the analysis of certified and groundwater samples spiked with a known amount of mercury and for the quantification of methylmercury in synthetic oceanic water, originally utilized for fishes contamination experiment.

Preferência alimentar da formiga urbana Camponotus vittatus forel (Hymenoptera: Formicidae)

For an adequate management program of urban ants, knowledge on their biology is required, with the aim of detecting and exploring their vulnerabilities. This type of information has been used in the manufacture of baits, which must show, among other characteristics, attractiveness to several species to be considered efficient and economically viable. Therefore, the present study was aimed to evaluate in the laboratory the attractiveness of sweet and fatty substances to Camponotus vittatus, trying to find which substances would be more efficient to be introduced as the attractive component in baits. Five colonies, 68 sweet substances and 23 fatty substances were utilized in the laboratory trials. The most attractive sweet and fatty substances, were, respectively, 75% demerara sugar and vegetable fat. When substances of both natures were tested together, sweet substances presented slightly higher attractive indexes than oily substances.

Avaliação da população canina da zona urbana do Município de Araçatuba, São Paulo, SP, Brasil

Planning control programs, for diseases such as rabies requires information on the size and structure of the dog and cat population. In order to evaluate the dog population of the urban area of Araçatuba city, S. Paulo State, Brazil, a survey was conducted using a questionnaire to interview members of households. Eighty-eight districts were visited (37,778 houses) and the interview was possible at 77.93% of these. Human population size evaluated was 113,157 inhabitants. Houses that owned animals represented 55.2%, 26,926 of the animals concerned were dogs and 5,755 were cats. Of the dogs, 56.64% were 1-4 year olds and males represented 56.2% of the total population. Dog: person ratio was estimated at 2.8 dogs to every 10 persons, almost 3 times the ratio hitherto estimated and used in the planning of rabies vaccination campaigns.

Monosodium glutamate in standard and high-fiber diets: Metabolic syndrome and oxidative stress in rats

Objective: This study determined the effects of adding monosodium glutamate (MSG) to a standard diet and a fiber-enriched diet on glucose metabolism, lipid profile, and oxidative stress in rats. Methods: Male Wistar rats (65 ± 5 g, n = 8) were fed a standard diet (control), a standard diet supplemented with 100 g of MSG per kilogram of rat body weight, a diet rich in fiber, or a diet rich in fiber supplemented with 100 g of MSG per kilogram of body weight. After 45 d of treatment, sera were analyzed for concentrations of insulin, leptin, glucose, triacylglycerol, lipid hydroperoxide, and total antioxidant substances. A homeostasis model assessment index was estimated to characterize insulin resistance. Results: Voluntary food intake was higher and feed efficiency was lower in animals fed the standard diet supplemented with MSG than in those fed the control, fiber-enriched, or fiber- and MSG-enriched diet. The MSG group had metabolic dysfunction characterized by increased levels of glucose, triacylglycerol, insulin, leptin, and homeostasis model assessment index. The adverse effects of MSG were related to an imbalance between the oxidant and antioxidant systems. The MSG group had increased levels of lipid hydroperoxide and decreased levels of total antioxidant substances. Levels of triacylglycerol and lipid hydroperoxide were decreased in rats fed the fiber-enriched and fiber- and MSG-enriched diets, whereas levels of total antioxidant substances were increased in these animals. Conclusions: MSG added to a standard diet increased food intake. Overfeeding induced metabolic disorders associated with oxidative stress in the absence of obesity. The fiber-enriched diet prevented changes in glucose, insulin, leptin, and triacylglycerol levels that were seen in the MSG group. Because the deleterious effects of MSG, i.e., induced overfeeding, were not seen in the animals fed the fiber-enriched diets, it can be concluded that fiber supplementation is beneficial by discouraging overfeeding and improving oxidative stress that is induced by an MSG diet. © 2005 Elsevier Inc. All rights reserved.

Microcontrolled pyro-electric instrument for measuring X-ray intensity in mammography

A novel instrument for measurement of X-ray intensity from mammography consists of a sensitive pyro-electric detector, a high-sensitivity, low-noise current-to-voltage converter, a microcontroller and a digital display. The heart of this device, and what makes it unique is the pyro-electric detector, which measures radiation by converting heat from absorbed incident X-rays into an electric current. This current is then converted to a voltage and digitised. The detector consists of a ferro-electric crystal; two types were tested; lithium tantalate and lithium niobate. X-ray measurement in mammography is challenging because of its relatively low photon energy range, from 11 keV to 15 keV equivalent mean energy, corresponding to a peak tube potential from 22 to 36 kV. Consequently, energy fluence rate or intensity is low compared with that of common diagnostic X-ray. The instrument is capable of measuring intensities as low as 0.25 mWm -2 with precision greater than 99%. Not only was the instrument capable of performing in the clinical environment, with high background electromagnetic interference and vibration, but its performance was not degraded after being subjected to 140 roentgen (3.6 × 10 -2 C kg -2 air) as measured by piezo-electric (d 33) or pyro-electric coefficients. © IFMBE 2005.

Electrophysiological responses of Atta sexdens rubropilosa workers to essential oils of Eucalyptus and its chemical composition

The leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 is the most harmful of the Eucalyptus pests, causing severe losses in wood production through defoliation. Various strategies have been tried and effort spent on the development of methods to control this pest, however no practical and environmentally acceptable one currently exists. In this work the chemical composition of the essential oil of seven Eucalyptus species was identified and the selectivity and sensitivity of antennal receptors of A. sexdens rubropilosa workers to the volatile compounds were determined using the electroantennographic technique (EAG and GC-EAD). Analysis by GC-EAD showed in E. cloesiana and E. maculata, respectively, seventeen and sixteen terpenes that elicited responses in ant workers' antennae, indicating the potential role of the essential oils as allelochemicals that determine the choice of the foraging material. © 2006 Verlag der Zeitschrift für Naturforschung.