992 resultados para 183-1136


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The Tie-2 receptor has been shown to play a role in angiogenesis in atherosclerosis. The conventional method assaying the level of soluble Tie-2 (sTie-2) was ELISA. However, this method has some disadvantages. The aims of this research are to establish a more simple detection method, the optical protein-chip based on imaging ellipsomtry (OPC-IE) applying to Tie-2 assay. The sTie-2 biosensor surface on silicon wafer was prepared first, and then serum levels of sTie-2 in 38 patients with AMI were measured on admission (day 1), day 2, day 3 and day 7 after onset of chest pain and 41 healthy controls by ELISA and OPC-IE in parallel. Median level of sTie-2 increased significantly in the AMI patients when compared with the controls. Statistics showed there was a significant correlation in sTie-2 results between the two methods (r=0.923, P0.01). The result of this study showed that the level of sTie-2 increased in AMI, and OPC-IE assay was a fast, reliable, and convenient technique to measure sTie-2 in serum.

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This paper provides an overview of fisheries legislation in Kenya, Uganda and Tanzania as far it concerns the administration of Lake Victoria's fishery. It also provides brief comment on the structure of these nations' fisheries departments and how they have evolved in recent years. The administration of Kenya's Lake Victoria fishery has changed very little since the introduction of the 1988 Fisheries Act. In Tanzania and Uganda, however, government policies of decentralization have had a profound impact on fisheries administration at a local level. This paper examines these changes and speculates about possible future management scenarios for these two countries

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A total of sixty juvenile Oreochromis niloticus (Nile tilapia) were fed three species of aquatic weed, namely Azolla filiculoides (water fern), Elodea sp. and Pistia stratiotes (water lettuce) to determine which of the weeds will be selectively consumed, and preferred of all. A control group of twenty Nile tilapia was fed compounded feed. The selectivity of the weeds was observed based on their utilization as food source, and Azolla filiculoides was found to be highly utilized, followed by Elodea sp. and the roots of Pistia stratiotes. The growth response of the fish to the diets was found to be highest for fish fed compounded feed followed by Azolla filiculoides and Elodea sp., while Pistia stratiotes produced a negative growth trend. It is therefore postulated that Azolla filiculoides and Pista sp. are good feedstuffs for O. niloticus especially when used together with other feedstuffs

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Seit 1996 werden im Institut für Fischereitechnik (IFH) fangtechnische Untersuchungen zwecks Reduzierung des Beifangs bei der stark discardbelasteten Aalschleppnetzfischerei in der Ostsee durchgeführt. Diese Arbeiten wurden in Zusammenarbeit mit dem Institut für Fischerei der Landesforschungsanstalt für Landwirtschaft und Fischerei Mecklenburg-Vorpommern sowie dem Verein MARITEC e. V. durchgeführt (Gabriel und Thiele 1997; Gabriel et al. 1998). Nach Auswertung der bisher vorliegenden Ergebnisse und nach einer weiterführenden Beifanganalyse zur Schleppnetzfischerei auf Grundfischarten, insbesondere Plattfisch, in den Küstengewässern Mecklenburg-Vorpommerns wurden 1998 folgende technische Untersuchungen vorgesehen: • Überprüfung einer kombinierten Fischerei mit Plattfisch-Grundschleppnetzen und passiven Aalfanggeräten (Körbe, Langleinen, Korbketten) • Erprobung einer neuen Steertkonstruktion im Plattfischfang auf verbesserte Selektionseigenschaften • Blankaalfang mit einern pelagischen Tucknetz • Versuche in der passiven Fischerei mit verbesserten bzw. neuartigen Aalfanggeräten

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32 Proben verpackten Frischfischs in Selbstbedienungspackungen, 16 Seelachs- und 16 Rotbarschproben aus deutschen Supermärkten wurden mit physikalischen, chemischen, mikrobiellen und sensorischen Methoden untersucht. Ziel der Untersuchung war dieWertung von Untersuchungsmethoden zur Qualitätsbestimmung. Es zeigte sich, daß neben der sensorischen Beurteilung die Bestimmung des TVB-N geeignet ist, die Qualität dieser Produkte zu beurteilen.

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ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority of a Convention, originally negotiated between the Governments of the Republic of Costa Rica and the United States of America, which entered into force in 1950. The Republic of Panama adhered to the Convention in 1953. The Convention is open to adherence of other nations having an interest in the tuna and tuna-bait resources of the Eastern Tropical Pacific Ocean. SPANISH: La Comisión Interamericana del Atún Tropical funciona bajo la autoridad de una Convención que originalmente fue negociada entre los Gobiernos de la Republica de Costa Rica y de los Estados Unidos de America y entro en vigencia en 1950; la Republica de Panamá se adhirió a la Convención en 1953. Esta Convención esta abierta para otras naciones que tengan interés en los recursos de atún y de las especies de carnada en el Océano Pacifico Oriental Tropical (PDF contains 183 pages.)

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Superprotonic phase transitions and thermal behaviors of three complex solid acid systems are presented, namely Rb3H(SO4)2-RbHSO4 system, Rb3H(SeO4)2-Cs3H(SeO4)2 solid solution system, and Cs6(H2SO4)3(H1.5PO4)4. These material systems present a rich set of phase transition characteristics that set them apart from other, simpler solid acids. A.C. impedance spectroscopy, high-temperature X-ray powder diffraction, and thermal analysis, as well as other characterization techniques, were employed to investigate the phase behavior of these systems.

Rb3H(SO4)2 is an atypical member of the M3H(XO4)2 class of compounds (M = alkali metal or NH4+ and X = S or Se) in that a transition to a high-conductivity state involves disproportionation into two phases rather than a simple polymorphic transition [1]. In the present work, investigations of the Rb3H(SO4)2-RbHSO4 system have revealed the disproportionation products to be Rb2SO4 and the previously unknown compound Rb5H3(SO4)4. The new compound becomes stable at a temperature between 25 and 140 °C and is isostructural to a recently reported trigonal phase with space group P3̅m of Cs5H3(SO4)4 [2]. At 185 °C the compound undergoes an apparently polymorphic transformation with a heat of transition of 23.8 kJ/mol and a slight additional increase in conductivity.

The compounds Rb3H(SeO4)2 and Cs3H(SeO4)2, though not isomorphous at ambient temperatures, are quintessential examples of superprotonic materials. Both adopt monoclinic structures at ambient temperatures and ultimately transform to a trigonal (R3̅m) superprotonic structure at slightly elevated temperatures, 178 and 183 °C, respectively. The compounds are completely miscible above the superprotonic transition and show extensive solubility below it. Beyond a careful determination of the phase boundaries, we find a remarkable 40-fold increase in the superprotonic conductivity in intermediate compositions rich in Rb as compared to either end-member.

The compound Cs6(H2SO4)3(H1.5PO4)4 is unusual amongst solid acid compounds in that it has a complex cubic structure at ambient temperature and apparently transforms to a simpler cubic structure of the CsCl-type (isostructural with CsH2PO4) at its transition temperature of 100-120 °C [3]. Here it is found that, depending on the level of humidification, the superprotonic transition of this material is superimposed with a decomposition reaction, which involves both exsolution of (liquid) acid and loss of H2O. This reaction can be suppressed by application of sufficiently high humidity, in which case Cs6(H2SO4)3(H1.5PO4)4 undergoes a true superprotonic transition. It is proposed that, under conditions of low humidity, the decomposition/dehydration reaction transforms the compound to Cs6(H2-0.5xSO4)3(H1.5PO4)4-x, also of the CsCl structure type at the temperatures of interest, but with a smaller unit cell. With increasing temperature, the decomposition/dehydration proceeds to greater and greater extent and unit cell of the solid phase decreases. This is identified to be the source of the apparent negative thermal expansion behavior.

References

[1] L.A. Cowan, R.M. Morcos, N. Hatada, A. Navrotsky, S.M. Haile, Solid State Ionics 179 (2008) (9-10) 305.

[2] M. Sakashita, H. Fujihisa, K.I. Suzuki, S. Hayashi, K. Honda, Solid State Ionics 178 (2007) (21-22) 1262.

[3] C.R.I. Chisholm, Superprotonic Phase Transitions in Solid Acids: Parameters affecting the presence and stability of superprotonic transitions in the MHnXO4 family of compounds (X=S, Se, P, As; M=Li, Na, K, NH4, Rb, Cs), Materials Science, California Institute of Technology, Pasadena, California (2003).

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[ES] Los movimientos migratorios forman parte de la historia universal. La población inmigrante, igual que el resto de la población, puede sufrir malnutrición. Los indicadores de la nutrición en inmigrantes son los mismos que en los autóctonos. La valoración nutricional debe realizarse de forma sistematica, mediante antropometría, historia clínica y dietética, etc. Se puede realizar de forma objetiva o subjetiva.

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In July 1994 an internationally coordinated and EU financed multidisciplinary research project about Baltic cod recruitment was started. The primary goals are to identify and describe dominant biotic and abiotic processes affecting the developmental success of early stages and the maturation of cod in the Central Baltic, to incorporate these processes into recruitment models in order to enhance prediction of future stock fluctuations due to environmental pertubations, species interactions and fisheries management directives as a prerequisite for an integrated fish stock assessment in the Central Baltic and to evaluate the feasibility and possible effects of stock enhancement programs on stock and recruitment and providing the biological basis for assessing their economic value.

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The commonest organisms of the original Mexico lake complex are listed, including those that exist today in the Lago Viejo. In addition, a brief hydraulic history of this endorheic basin is given.

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This brief article provides some of the background to the publication of The Freshwater Algal Flora of the British Isles (John et al. 2002). This publication updates West and Fritsch's A Treatise on British Freshwater Algae (2nd edition) which was published in 1927. Taxonomic experts on the major freshwater algal groups were approached and almost all agreed to collaborate. The book which has taken more than 10 years to complete is illustrated with over 2000 line drawings and there are 20 half tone plates.

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Isoprene (ISO),the most abundant non-methane VOC, is the major contributor to secondary organic aerosols (SOA) formation. The mechanisms involved in such transformation, however, are not fully understood. Current mechanisms, which are based on the oxidation of ISO in the gas-phase, underestimate SOA yields. The heightened awareness that ISO is only partially processed in the gas-phase has turned attention to heterogeneous processes as alternative pathways toward SOA.

During my research project, I investigated the photochemical oxidation of isoprene in bulk water. Below, I will report on the λ > 305 nm photolysis of H2O2 in dilute ISO solutions. This process yields C10H15OH species as primary products, whose formation both requires and is inhibited by O2. Several isomers of C10H15OH were resolved by reverse-phase high-performance liquid chromatography and detected as MH+ (m/z = 153) and MH+-18 (m/z = 135) signals by electrospray ionization mass spectrometry. This finding is consistent with the addition of ·OH to ISO, followed by HO-ISO· reactions with ISO (in competition with O2) leading to second generation HO(ISO)2· radicals that terminate as C10H15OH via β-H abstraction by O2.

It is not generally realized that chemistry on the surface of water cannot be deduced, extrapolated or translated to those in bulk gas and liquid phases. The water density drops a thousand-fold within a few Angstroms through the gas-liquid interfacial region and therefore hydrophobic VOCs such as ISO will likely remain in these relatively 'dry' interfacial water layers rather than proceed into bulk water. In previous experiments from our laboratory, it was found that gas-phase olefins can be protonated on the surface of pH < 4 water. This phenomenon increases the residence time of gases at the interface, an event that makes them increasingly susceptible to interaction with gaseous atmospheric oxidants such as ozone and hydroxyl radicals.

In order to test this hypothesis, I carried out experiments in which ISO(g) collides with the surface of aqueous microdroplets of various compositions. Herein I report that ISO(g) is oxidized into soluble species via Fenton chemistry on the surface of aqueous Fe(II)Cl2 solutions simultaneously exposed to H2O2(g). Monomer and oligomeric species (ISO)1-8H+ were detected via online electrospray ionization mass spectrometry (ESI-MS) on the surface of pH ~ 2 water, and were then oxidized into a suite of products whose combined yields exceed ~ 5% of (ISO)1-8H+. MS/MS analysis revealed that products mainly consisted of alcohols, ketones, epoxides and acids. Our experiments demonstrated that olefins in ambient air may be oxidized upon impact on the surface of Fe-containing aqueous acidic media, such as those of typical to tropospheric aerosols.

Related experiments involving the reaction of ISO(g) with ·OH radicals from the photolysis of dissolved H2O2 were also carried out to test the surface oxidation of ISO(g) by photolyzing H2O2(aq) at 266 nm at various pH. The products were analyzed via online electrospray ionization mass spectrometry. Similar to our Fenton experiments, we detected (ISO)1-7H+ at pH < 4, and new m/z+ = 271 and m/z- = 76 products at pH > 5.