HPLC fluorometric determination of natural phytoplankton phycocyanin and its usefulness as cyanobacterial biomass in highly eutrophic shallow lake     

Akira Otsuki  Takehiko Omi  Shinya Hashimoto  Morihiro Aizaki  Noriko Takamura 《Water, air, and soil pollution》1994,76(3-4):383-396

A method for HPLC determination of phycocyanin in phytoplankton samples using gelchromatography with a fluorescence detector was developed to examine the use of phycocyanin as an index of the appearance and progress of cyanobacterial blooms in highly eutrophic lake. At least two types of phycocyanin with different molecular weights, each spectroscopically different from phycoerythrin and allophycocyanin, were found in natural phytoplankton samples. Changes in phycocyanin concentrations were clearly coupled to changes in chlorophyll-a concentrations during June to October while cyanobacterial blooms were occurring. The chlorophyll-a to phycocyanin relationship was linear at chlorophyll-a concentrations of less than 250 μg L^?1. The relationship between cyanobacterial carbon and phycocyanin concentration was also linear, suggesting that phycocyanin content may be a useful index of cyanobacterial biomass in highly eutrophic lakes where large cyanobacterial blooms occur.  相似文献   

Regional Sediment Deficits in the Dutch Lowlands: Implications for Long-Term Land-Use Options (8 pp)     

Michiel J. van der Meulen  Ad J. F. van der Spek  Ger de Lange  Stephan H. L. L. Gruijters  Serge F. van Gessel  Buu-Long Nguyen  Denise Maljers  Jeroen Schokker  Jan P. M. Mulder  Rob A. A. van der Krogt 《Journal of Soils and Sediments》2007,7(1):9-16

Background, Aim and Scope   Coastal and river plains are the surfaces of depositional systems, to which sediment input is a parameter of key-importance. Their habitation and economic development usually requires protection with dikes, quays, etc., which are effective in retaining floods but have the side effect of retarding sedimentation in their hinterlands. The flood-protected Dutch lowlands (so-called dike-ring areas) have been sediment-starved for up to about a millennium. In addition to this, peat decomposition and soil compaction, brought about by land drainage, have caused significant land subsidence. Sediment deficiency, defined as the combined effect of sediment-starvation and drainage-induced volume losses, has already been substantial in this area, and it is expected to become urgent in view of the forecasted effects of climate change (sea-level rise, intensified precipitation and run-off). We therefore explore this deficiency, compare it with natural (Holocene) and current human sediment inputs, and discuss it in terms of long-term land-use options. Materials and Methods: We use available 3D geological models to define natural sediment inputs to our study area. Recent progress in large-scale modelling of peat oxidation and compaction enables us to address volume loss associated with these processes. Human sediment inputs are based on published minerals statistics. All results are given as first-order approximations. Results: The current sediment deficit in the diked lowlands of the Netherlands is estimated at 136 ± 67 million m3/a. About 85% of this volume is the hypothetical amount of sediment required to keep up with sea-level rise, and 15% is the effect of land drainage (peat decomposition and compaction). The average Holocene sediment input to our study area (based on a total of 145 km3) is ~14 million m3/a, and the maximum (millennium-averaged) input ~26 million m3/a. Historical sediment deficiency has resulted in an unused sediment accommodation space of about 13.3 km3. Net human input of sediment material currently amounts to ~23 million m3/a. Discussion: As sedimentary processes in the Dutch lowlands have been retarded, the depositional system's natural resilience to sea-level rise is low, and all that is left to cope is human countermeasure. Preserving some sort of status quo with water management solutions may reach its limits in the foreseeable future. The most viable long-term solutions therefore seem a combination of allowing for more water in open country (anything from flood-buffer zones to open water) and raising lands that are to be built up (enabling their lasting protection). As to the latter, doubling or tripling the use of filling sand in a planned and sustained effort may resolve up to one half of the Dutch sediment deficiency problems in about a century. Conclusions: Conclusions, Recommendations and Perspectives. We conclude that sediment deficiency – past, present and future – challenges the sustainable habitation of the Dutch lowlands. In order to explore possible solutions, we recommend the development of long-term scenarios for the changing lowland physiography, that include the effects of Global Change, compensation measures, costs and benefits, and the implications for long-term land-use options. Recommendations and Perspectives: -  相似文献   

Risk factors of obesity among Brazilian adolescents: a case-control study     

Neutzling MB  Taddei JA  Gigante DP 《Public health nutrition》2003,6(8):743-749

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Ascorbic acid oxidation in sucrose aqueous model systems at subzero temperatures     

Champion D  Simatos D  Kalogianni EP  Cayot P  Le Meste M 《Journal of agricultural and food chemistry》2004,52(11):3399-3404

The reduction of Tempol by ascorbic acid in concentrated sucrose solutions was measured by electron paramagnetic resonance (EPR) at temperatures ranging from 16 to -16 degrees C. This method allowed the determination of the rate constants (k) of this fast reaction, by recording the Tempol reduction as a function of time. The two reactants were initially separated and had to migrate for the reaction to occur. The experimental findings were compared with predicted values according to the equation for diffusion-controlled reaction proposed by Atkins. The experimental reaction rate constants were observed to be lower than the calculated ones. However, the experimental values were found to be controlled by the temperature and viscosity changes of the reaction media, as expected for a diffusion-controlled reaction.  相似文献   

Longitudinal trends in pH and aluminum chemistry of the Coxing Kill,Ulster County,New York     

Alexandra M. Shultz  Marianne H. Begemann  Denise A. Schmidt  Kathleen C. Weathers 《Water, air, and soil pollution》1993,69(1-2):113-125

The purpose of this work was to characterize the Al chemistry along the longitudinal pH gradient of the Coxing Kill and thereby provide a basis for an in depth study of aluminum chemistry and transport as a function of pH. Water samples were collected along the pH gradient and analyzed for monomeric Al species, strong acid anions, base cations, ammonium, dissolved organic C and dissolved silica. Inorganic monomeric Al, organic momonmeric Al and dissolved organic C decreased in concentration as the stream's drainage area and pH increased. The ratio of organic to inorganic monomeric Al and the concentration of all other species increased with increasing pH. An abrupt change in stream chemistry occurred in conjunction with the gradual changes expected for a low order stream draining an acid sensitive watershed impacted by acid deposition. This abrupt change partially resulted from geological characteristics of the watershed.  相似文献   

Thyroid Hormone Concentrations In Critically III Canine Intensive Care Patients     

Denise A. Elliott  Lesley G. King  Carole A. Zerbe 《Journal of Veterinary Emergency and Critical Care》1995,5(1):17-23

Alterations in thyroid indices in critically ill dogs were studied retrospectively to determine the incidence of the euthyroid sick syndrome and to assess its prognostic relevance to survival. Sixty-seven dogs were classified as euthyroid bases on a TSH stimulation test. Forty-one of 67 (61%) of the euthyroid dogs had low baseline serum T₄ concentrations (<1.5 ug/dl) and 38 of 67 (56%) of the euthyroid dogs had low baseline serum T₃ concentrations (<75 ng/dl). There was no significant difference between either the baseline or the post-stimulation serum T₄ concentrations when values of dogs that survived were compared with those that died. There was, however, a significant difference (P<0.05) between both the baseline and the post-stimulation values for T3 when survivors (100.3± 81 ng/dl, 143± 66 ng/dl) and non-survivors (64.2 ± 17.1 ng/dl, 96.6 ± 38.3 ng/dl) were compared. The euthyroid sick syndrome occurs commonly in critically ill dogs. Further, the extent of depression of serum concentrations of T₃ may be correlated to mortality.  相似文献   

Isolation of influenza A viruses from migratory waterfowl in San-in District, western Japan in the winter of 1983-1984   总被引：1，自引：0，他引：1  

K Otsuki  O Takemoto  R Fujimoto  K Yamazaki  N Kubota  H Hosaki  T Mitani  M Tsubokura 《Research in veterinary science》1987,43(2):177-179

Certain species of winter migratory waterfowl in San-in District, western Japan, were surveyed for influenza virus from November 1983 to March 1984. Faeces of the waterfowl were collected regularly at five stations. Eleven influenza A viruses including H5N3 and H10N4 subtypes were isolated from 450 faecal samples from whistling swans, 28 viruses including H2N2 and H10N4 subtypes were isolated from 362 faecal samples from pintails; and subtype H13N6 was isolated from 240 faecal samples of black-tailed gulls.  相似文献   

Validity of a health-related quality-of-life scale for dogs with signs of pain secondary to cancer     

Yazbek KV  Fantoni DT 《Journal of the American Veterinary Medical Association》2005,226(8):1354-1358

OBJECTIVE: To develop and validate a health-related quality-of-life scale for dogs with pain secondary to cancer. DESIGN: Questionnaire development. ANIMALS: 40 healthy dogs with no history or signs of pain, 20 dogs with dermatologic disease but no signs of pain other than mild pruritus, and 20 dogs with cancer. PROCEDURE: Owners of all dogs completed a questionnaire containing 12 questions with 4 options for each question, and a quality-of-life score ranging from 0 to 36 was calculated. Scores for dogs with cancer were compared with scores for healthy dogs and dogs with dermatologic disease. RESULTS: All owners indicated that the questionnaire was easy to complete. Scores for healthy dogs were significantly different from scores for dogs with cancer and scores for dogs with dermatologic disease. Scores for dogs with dermatologic disease were significantly different from scores for dogs with cancer. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a simple questionnaire may be useful in assessing health-related quality of life in dogs with pain secondary to cancer, in that dogs with cancer had significantly lower scores than did healthy dogs and dogs with dermatologic disease.  相似文献   

Detection of the esp gene in high-level gentamicin resistant Enterococcus faecalis strains from pet animals in Japan   总被引：1，自引：0，他引：1  

Harada T  Tsuji N  Otsuki K  Murase T 《Veterinary microbiology》2005,106(1-2):139-143

We investigated the prevalence of the esp gene and the susceptibility to gentamicin in Enterococcus faecalis and E. faecium strains obtained from pet animals. Nine of 30 E. faecalis and 2 of 38 E. faecium strains from the pet animals had the esp gene. Three esp-positive E. faecalis strains, which were isolated from two dogs and a cat, showed gentamicin MICs of > or =256 microg/ml and harbored the high-level gentamicin resistance (HLGR) gene, aac(6')-Ie-aph(2')-Ia. Of the nine esp-positive E. faecalis strains, five, including the three strains with the HLGR gene, were closely related by numerical analysis of PFGE patterns. Longitudinal investigation needs to elucidate whether the HLGR gene was incorporated into a subpopulation of the esp-positive E. faecalis.  相似文献   

Electron microscopy of fine structure of Corynebacterium renale with special reference to pili   总被引：5，自引：0，他引：5  

R Yanagawa  K Otsuki  T Tokui 《The Japanese journal of veterinary research》1968,16(1):31-37

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