Factors influencing fluoride concentrations in Norwegian lakes     

Brit Lisa Skjelkvåle 《Water, air, and soil pollution》1994,77(1-2):151-167

The sources and mechanisms regulating fluoride (F) in Norwegian lake waters are studied using data from regional surveys of precipitation chemistry, lake water chemistry and bedrock geology. Fluoride concentrations in Norwegian lakes range from < 5 to 560 μg L^?1. Fluoride content in the bedrock is the most important factor controlling F levels in lake waters, as shown by significant differences in median value of F concentrations between lakes situated in different geological provinces. There are also weak but significant correlations between F in the lakes and components typical for weathering such as non-marine Ca, Mg, Na and K. The regional picture of F concentration in lake water shows elevated F concentrations in the acidified areas in southern and southeastern Norway compared to other regions of the country with comparable geology. There is a weak but significant correlation between F and SO₄, a typical indicator of acidification in surface water. Mass balance calculations in three catchments show that F is retained in soils in pristine areas, while F output exceeds precipitation input in acidified areas. This both demonstrates the strong retention capacity for F in soils and indicates that anthropogenic F added through polluted rain is a minor source of F in surface waters. Fluoride is mobilized in acidifies areas, probably due to complexation with Al.  相似文献   

Assessment of Nitrogen Leaching at ICP-Waters Sites (Europe and North America)     

John L. Stoddard  Tor S. Traaen  Brit Lisa Skjelkvåle 《Water, air, and soil pollution》2001,130(1-4):781-786

The International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP-Waters) is designed to assess the degree and geographical extent of acidification of surface waters. During the last 20 years, international emission reduction measures in Europe and North America have resulted in a decrease in atmospheric S-deposition of up to 50%, while N-deposition has stayed almost constant. Empirical relationships between N-deposition and stages of nitrogen saturation are used to assess the importance of nitrogen leaching at the ICP-Waters sites in Europe and North America. There is a clear coherence between high N saturation stages and high N deposition loads and more than 50% of the analysed ICP Waters sites show a high degree of nitrogen saturation, defined as stages 2 or 3 in Stoddard's classification system. Significant leaching of inorganic N also occurs at most sites with deposition greater than 10 kg/ha/yr.  相似文献   

Decrease in Acid Deposition - Recovery in Norwegian Waters     

Brit Lisa Skjelkvåle  Kjetil Tørseth  Wenche Aas  Tom Andersen 《Water, air, and soil pollution》2001,130(1-4):1433-1438

Concentrations of sulphate in precipitation in southern Norway have decreased by 50–60% from 1980–1999. This has caused a decrease in sulphate concentrations in lakes of 30–40% from 1986–1999. Nitrogen in precipitation has decreased slightly over the last 10-years. In lakewater there has also been a significant but slight decrease. Concentrations of non-marine base cations in precipitation have decreased by 40% from 1980–1999. In lakewater, non-marine base cation concentrations have been at about the same level the last 10 years. This indicates that acid deposition has decreased sufficiently such that the pool of exchangeable base cations in the soil is now being replenished. The acidification situation in lakes in Norway has thus shown a clear improvement over the last 8–10 years. pH, alkalinity and ANC (acid neutralising capacity) have all increased. Concentrations of inorganic (toxic) aluminium species have decreased. The trends in H⁺ and Alⁿ⁺ do not follow the relation expected if Alⁿ⁺ concentrations were governed solely by a single solid phase of Al(OH)₃.  相似文献   

Isoflavonoids isolated from Cuban propolis   总被引：3，自引：0，他引：3  

Piccinelli AL  Campo Fernandez M  Cuesta-Rubio O  Márquez Hernández I  De Simone F  Rastrelli L 《Journal of agricultural and food chemistry》2005,53(23):9010-9016

Chemical investigation of a red-type Cuban propolis sample has led to the isolation of 11 isoflavonoids (2 isoflavones, 3 isoflavans, and 6 pterocarpans), together with gallic acid, isoliquiritigenin, and (-)-liquiritigenin. Structural determination, including the absolute stereochemistry, was accomplished by spectroscopic analysis, particularly CD and 2D NMR techniques. The fragmentation behavior of pterocarpans was studied by electrospray ionization (ESI) tandem mass spectrometry (MS/MS) using an ion-trap analyzer, and a generalized fragmentation pathway, useful in the identification and structural characterization of pterocarpans, is proposed. Isoflavonoids are reported for the first time from propolis samples.  相似文献   

Relating microarthropod community structure and diversity to soil fertility manipulations in temperate grassland     

Lisa Cole  Sarah M. Buckland 《Soil biology & biochemistry》2005,37(9):1707-1717

We aimed to identify patterns of diversity in a below-ground community of microarthropods (mites and Collembola) after 15 months of a nutrient (calcium and nitrogen) manipulation experiment, located at the Natural Environment Research Council (NERC) Soil Biodiversity Site in Scotland, UK. We found that microarthropod densities increased with elevated soil fertility, but we detected no concurrent change in the diversity of soil microarthropods (mites and Collembola combined). That microarthropod density increased concurrently with improvements in soil fertility and plant productivity suggests that soil microarthropod communities are predominately regulated by bottom-up forces, driven by increased energy transfer via plant inputs to soil, providing increased food resources for fauna. However, that we found no concurrent change in the diversity of soil microarthropods provides little support for the idea that the diversity of soil fauna is positively related to their population density, primary productivity or improvements in soil conditions resulting from nutrient manipulations. However, we did find that microarthropod communities of more fertile sites contained a greater proportion of predators suggesting that more energy was transferred to higher trophic levels under elevated soil fertility. Our findings suggest that unlike plant communities, soil faunal diversity may not be strongly regulated by competition in productive situations, since competitive exclusion might not occur due to increased predation. Whilst we conclude that soil microarthropod diversity at our study site has not been affected by the nutrient additions to date, in the longer term we predict that changes in community composition and diversity could arise, most likely through top-down regulation of the soil food web.  相似文献   

Predictors of pregnancy and postpartum haemoglobin concentrations in low-income women   总被引：1，自引：0，他引：1  

Bodnar LM  Siega-Riz AM  Arab L  Chantala K  McDonald T 《Public health nutrition》2004,7(6):701-711

OBJECTIVE: Pregnancy and postpartum iron status is of great public health importance, yet few studies have examined predictors of haemoglobin (Hb) concentration during this time. We identified predictors of Hb from 24 weeks' gestation until delivery and from 4 to 25 weeks postpartum. DESIGN: Blood was drawn as many as four times during care: at the initial visit, at 24-29 weeks' gestation, at delivery and postpartum. A longitudinal, multivariable linear regression model was used to predict Hb concentration. SETTING: A public health clinic in Raleigh, North Carolina.Subjects: n=520 women who participated in the Iron Supplementation Study. RESULTS: Hb concentration at the previous blood draw, short stature, non-Hispanic white ethnicity/race, >12 years of education and smoking were positive predictors of pregnancy and postpartum Hb concentrations. Iron supplement use was a positive predictor, while inadequate weight gain and severe nausea/vomiting were negative predictors of gestational Hb. A high infant birth weight and postpartum haemorrhage were negative predictors of postpartum Hb. Pre-pregnancy body mass index had a slight positive relationship with gestational Hb, but had a strong negative relationship with postpartum Hb. The longitudinal model also confirmed the typical pattern of gestational Hb concentration. As the number of weeks between the initial visit and the 24- to 29-week visit increased, Hb at 24-29 weeks' gestation decreased. As gestational age increased from 24 weeks until delivery, Hb concentration increased as well. CONCLUSIONS: The predictors identified here could be used in clinical settings to target high-risk women for intervention.  相似文献   

Direct HPLC analysis of quercetin and trans-resveratrol in red wine,grape, and winemaking byproducts   总被引：1，自引：0，他引：1  

Careri M  Corradini C  Elviri L  Nicoletti I  Zagnoni I 《Journal of agricultural and food chemistry》2003,51(18):5226-5231

A simple and fast reversed-phase HPLC method using diode array detection was developed and validated for the simultaneous determination of trans-resveratrol and quercetin in Sicilian red wine from the Nero d'Avola red grape variety. Investigation was also extended to the quantitative determination of resveratrol and quercetin in grape skins and winemaking byproducts obtained from the same cultivar. Samples were eluted using a C18 narrow-bore column under isocratic conditions in less than 20 min. Quantification of trans-resveratrol and quercetin in red wine was performed without any sample pretreatment, whereas the determination of these phenolic compounds in grape skins and wine pomage required a solvent extraction procedure. Linearity was demonstrated over the 0.39-12.5 and 0.45-57.6 microg/mL range for trans-resveratrol and quercetin, respectively. Detection limits in real samples were in the low ppm level (0.07 mg/L for trans-resveratrol and 0.12 mg/L for quercetin). The HPLC-UV/DAD method was applied for the routine analyses of red wine and grape skin and winemaking byproduct extracts to evaluate their trans-resveratrol and quercetin content. In particular, a very high content of quercetin was found in wine pomace, suggesting the use of this wine byproduct as a potential source of this health-promoting phenolic compound.  相似文献   

Clinical Vignette   总被引：1，自引：0，他引：1  

Lisa Freeman  Jerry Stevens  Christine Loughman  Mary Tompkins 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(3):171-173

  相似文献   

Alterations in Lipoprotein Profiles in Dogs With Lymphoma     

Gregory K. Ogilvie  Richard B. Ford  David M. Vail  Lisa M. Walters  M. D. Salman  C. Babineau  Martin J. Fettman 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1994,8(1):62-66

After a 12-hour fast, blood samples were obtained from 31 dogs with previously untreated lymphoma. Blood samples were also collected from 16 of these dogs after up to 5 treatments with doxorubicin (30 mg/m² intravenously every 3 weeks). All 16 dogs underwent complete remission. Five dogs were re-evaluated after relapse and after overt signs of cancer cachexia had become clinically apparent. Samples were assayed for 8 quantitative parameters: total cholesterol (T-CH) and total triglyceride (T-TG) concentrations, and the concentration of cholesterol and triglyceride in each of the three major lipoprotein fractions, very-low-density lipoprotein (VLDL-CH and VLDL-TG), low-density lipoprotein (LDL-CH and LDL-TG), and high-density lipoprotein (HDL-CH and HDL-TG). The results were compared with those from 20 healthy control dogs of similar weight and age before and 3 weeks after being given one dose of doxorubicin (30 mg/m² intravenously). The administration of doxorubicin to control dogs resulted in a significant (P> .05) decrease in T-CH, LDL-CH, and HDL-CH, as well as a significant increase in VLOL-TG and HDL-TG. When compared with untreated controls, untreated dogs with lymphoma had significantly higher concentrations of VLDL-CH, T-TG, VLDL-TG, LDL-TG, and HDL-TG, and significantly lower concentrations of HDL-CH. HDL-TG and VLDL-TG concentrations from dogs with lymphoma were significantly increased above pretreatment values after relapse and development of overt signs of cancer cachexia. Dogs in remission that were evaluated after one dose of doxorubicin had significantly higher concentrations of T-CH, VLDL-CH, T-TG, and LDL-TG when compared with controls that were evaluated after an identical dose of doxorubicin. HDL-TG increased significantly over pretreatment values in dogs with lymphoma after doxorubicin therapy. These results suggest that dogs with lymphoma have significant alterations in lipid profiles, and with the possible exception of HDL-CH, these abnormalities do not normalize when clinical remission is obtained.  相似文献   

Analgesic efficacy of preoperative administration of meloxicam or butorphanol in onychectomized cats     

Carroll GL  Howe LB  Peterson KD 《Journal of the American Veterinary Medical Association》2005,226(6):913-919

OBJECTIVE: To determine analgesic efficacy and adverse effects of preemptive administration of meloxicam or butorphanol in cats undergoing onychectomy or onychectomy and neutering. DESIGN: Randomized controlled study. ANIMALS: 64 female and 74 male cats that were 4 to 192 months old and weighed 1.09 to 705 kg (2.4 to 15.5 lb). PROCEDURE: Cats received meloxicam (0.3 mg/kg [0.14 mg/lb], s.c.) or butorphanol (0.4 mg/kg [0.18 mg/lb], s.c.) 15 minutes after premedication and prior to anesthesia. A single blinded observer measured physiologic variables, assigned analgesia and lameness scores, and withdrew blood samples for each cat at baseline and throughout the 24 hours after surgery. Rescue analgesia (butorphanol, 0.4 mg/kg, i.v. or s.c.) or administration of acepromazine (0.025 to 0.05 mg/kg [0.011 to 0.023 mg/lb], i.v.) was allowed. RESULTS: Meloxicam-treated cats were less lame and had lower pain scores. Cortisol concentration was higher at extubation and lower at 1, 5, and 12 hours in the meloxicam-treated cats. Fewer meloxicam-treated cats required rescue analgesia at 3, 5, 12, and 24 hours after extubation. General impression scores were excellent or good in 75% of meloxicam-treated cats and 44% of butorphanol-treated cats. There was no treatment effect on buccal bleeding time; PCV and BUN concentration decreased in both groups, and glucose concentration decreased in meloxicam-treated cats. CONCLUSIONS AND CLINICAL RELEVANCE: Preoperative administration of meloxicam improved analgesia for 24 hours without clinically relevant adverse effects in cats that underwent onychectomy or onychectomy and neutering and provided safe, extended analgesia, compared with butorphanol.  相似文献