Methylmercury output from the Svartberget Catchment in northern Sweden during spring flood     

Kevin Bishop  Ying -Hua Lee  Catharina Pettersson  Bert Allard 《Water, air, and soil pollution》1995,80(1-4):445-454

The problem of mercury (Hg) accumulation in the aquatic food chain is widespread in Sweden. The methylmercury (MeHg) in runoff from catchments may be an important component of the MeHg load in surface waters. The spring flood in northern Sweden constitutes a major portion of the annual catchment runoff. This brief, but large event, therefore, may be of significance for the annual output of MeHg from soils to surface waters in this region. Methylmercury, total mercury (Hg-tot) and other chemical parameters were measured in spring flood runoff during April and May 1993 from two tributaries as well as the headwater mire of the 50 ha Svartberget Catchment. Snow cores from April 1993 and April 1994 prior to the onset of spring snowmelt were also analyzed. Stable isotope techniques were used to estimate the proportion of snowmelt in runoff. During the spring flood, Hg-tot and TOC were diluted in output from the headwater mire compared to the concentrations observed prior to the flood. Over half of the runoff from the mire was snowmelt according to the isotope Hydrograph separation. In runoff from the two forested tributaries, however, TOC and Hg-tot concentrations increased. About a third of this runoff was snowmelt. MeHg concentrations in the spring flood declined at all locations to the lowest levels recorded during 1993 (<0.2 ng l^?1). The runoff concentrations of MeHg were less than the average snow core concentration of 0.3 4+/- 0.17 ng l^?1. The differences in MeHg dynamics in comparison to TOC or Hg-tot suggest that there are factors independent of the availability of Hg-tot or TOC, and even contemporary MeHg deposition (in this case the snowpack MeHg concentrations) which determine the concentrations and output of MeHg during spring flood.  相似文献   

Peptides with angiotensin I-converting enzyme (ACE) inhibitory activity from defibrinated,hydrolyzed bovine plasma     

Wanasundara PK  Ross AR  Amarowicz R  Ambrose SJ  Pegg RB  Shand PJ 《Journal of agricultural and food chemistry》2002,50(24):6981-6988

Defibrinated bovine plasma (DBP) was treated with the microbial protease Flavourzyme to obtain protein hydrolysates with various degrees of hydrolysis (DH). The angiotensin I-converting enzyme (ACE) inhibiting activity of the hydrolyzed protein was assessed with hippuryl-His-Leu as the substrate. The amount of hippuric acid released, due to uninhibited ACE activity, was determined by high-performance liquid chromatography. ACE inhibiting (ACEI) activity was found to increase with increasing DH; the 43% DH hydrolysate exhibited the highest activity and had an IC(50) of 1.08 mg/mL. Peptide fractions with high ACEI activity were isolated using size exclusion chromatography. The fraction that possessed the highest ACEI activity contained peptides with GYP, HL(I), HPY, HPGH, L(I)F, SPY, and YPH sequence motifs, as determined by reversed-phase liquid chromatography-tandem mass spectrometry using a novel immonium precursor-ion scanning technique. Some of these motifs correspond to sequences found in bovine serum albumin, a potential source of ACEI peptides in bovine plasma.  相似文献   

Management of insect pests in celery and potato crops by pneumatic removal     

Phyllis G. Weintraub  Yossi Arazi  A.Rami Horowitz 《Crop Protection》1996,15(8):763-769

Over the course of 4 years, five sets of trials were run in celery and potato crops to evaluate the efficacy of a field-scale vacuum (FSV) unit for use in insect pest management. The unit was designed to dislodge insects by blowing air from lateral vents onto the plants while simultaneously vacuuming from above. Efficacy was evaluated by field observations, yellow sticky traps and hand vacuum sampling before and after the FSV. All insects evaluated were effectively removed by the vacuum unit; typically, population reductions of 50–75% were achieved with whiteflies, leafhoppers, and aphids. In some trials, reductions were achieved that lasted from week to week. Additionally, agromyzid leafminers were significantly reduced in number, but population reductions were temporary because of their strong flying ability.  相似文献   

Comparison of ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs     

Brömel C  Pollard RE  Kass PH  Samii VF  Davidson AP  Nelson RW 《American journal of veterinary research》2006,67(1):70-77

OBJECTIVE: To determine ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs and evaluate the relationships of thyroid gland size and volume with body weight and body surface area (BSA). ANIMALS: 72 dogs of small (6 Toy and 6 Miniature Poodles), medium (12 Beagles), and large breeds (12 Akitas and 36 Golden Retrievers). PROCEDURE: Each dog's thyroid gland was examined ultrasonographically with a 10- to 5-MHz multifrequency linear-array transducer. Size, shape, echogenicity, and homogeneity of thyroid lobes were evaluated on longitudinal and transverse images. Thyroid lobe volume was estimated by use of the equation for an ellipsoid (pi/6 [length x height x width]). RESULTS: Thyroid lobes appeared fusiform or elliptical on longitudinal images and triangular or round to oval on transverse images. In most dogs, thyroid lobes were hyperechoic or isoechoic, compared with surrounding musculature, and had a homogeneous echogenic pattern. Mean length, width, height, and volume of thyroid lobes were significantly greater in Akitas and Golden Retrievers, compared with findings in Beagles or Poodles; mean length, width, and height were significantly greater in Beagles, compared with findings in Poodles. Total thyroid gland volume correlated with body weight (r = 0.73) and BSA (r = 0.74). CONCLUSIONS AND CLINICAL RELEVANCE: Among the dog breeds examined ultrasonographically, thyroid lobe size and volume were more variable than shape, echogenicity, and homogeneity. The correlation of thyroid gland volume with BSA suggests that size of the dog, rather than breed, should be considered when assessing thyroid glands ultrasonographically.  相似文献   

Prevalence and antimicrobial resistance patterns of Salmonella enterica in preweaned calves from dairies and calf ranches     

Berge AC  Moore DA  Sischo WM 《American journal of veterinary research》2006,67(9):1580-1588

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Efficacy of a new slow-release volatile system against <Emphasis Type="Italic">Aphis gossypii</Emphasis> Glover (Hemiptera: Aphididae) on cucumber, <Emphasis Type="Italic">Cucumis sativus</Emphasis> L.     

Lilach Mondaca  Phyllis G. Weintraub  Eitan Recht 《Phytoparasitica》2017,45(5):667-672

Many arthropod agricultural pests have become resistant to pesticides through inappropriate usage. A consequence of this resistance is often cross-resistance with other pesticides with similar or related modes of actions. As a result of increasing pesticide resistance, a movement to alternative, ‘green’ botanical pesticides has been growing. A new formulation of volatile oils, extracted from a variety of plants allows for slow-release and longer duration in the field. In this publication we present results of the efficacy of one of these products against the cotton aphid Aphis gossypii on cucumber plants in replicated choice tests. The slow release Ap2, a Bio-Pel product from Newseal Mineral and Coatings Ltd. (hereafter Newseal), significantly reduced the population of aphids on test plants and prevented their movement upwards on the plant. Additionally, four Newseal products caused no mortality to the aphid parasitoid Aphidius colemani or to the generalist predator, Orius laevigatus.  相似文献   

Abstracts of papers presented at the 16th conference of the Entomological Society of Israel Research on thrips in Israel Dedicated to the Memory of Prof. E. Rivnay on the 100th Anniversary of his Birth     

M. Wysoki  M. Wysoki  M. Klein  M. Davidovich  R. Shaked  K. Rosenfeld  E. Pressman  Phyllis G. Weintraub  A. R. Horowitz  Sophia Kleitman  R. Azari  Leah Tsror  A. R. Horowitz  Phyllis G. Weintraub  Svetlana Kontsedalov  I. Ishaaya  Raisa Chyzik  M. Klein  Orna Ucko  S. Steinberg  M. Coll  D. Rosen  D. Gouldman  S. Steinberg  Ayala Lalouche  S. Steinberg  M. Coll  D. Ben-Yakir  M. Chen  Y. Antignus  Y. Messika  N. Dudai  A. Gera  Anat Kritzman  J. Cohen  B. Raccah 《Phytoparasitica》1999,27(3):243-250

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Cultural landscapes of the future: using agent-based modeling to discuss and develop the use and management of the cultural landscape of South West Devon     

Koen F. Tieskens  Brian J. Shaw  Toon Haer  Catharina J. E. Schulp  Peter H. Verburg 《Landscape Ecology》2017,32(11):2113-2132

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Supercritical fluid extraction and high-performance liquid chromatographic determination of phloroglucinols in St. John's Wort (Hypericum perforatum L.)     

Cui Y  Ang CY 《Journal of agricultural and food chemistry》2002,50(10):2755-2759

A small-scale supercritical fluid extraction (SFE) method was developed for the selective extraction of phloroglucinols from St. John's wort (SJW) leaf/flower mixtures using supercritical carbon dioxide (CO(2)). The extraction efficiency was investigated as influenced by pressure, temperature, time, and modifier. The optimized condition of SFE was carried out at 3.80 x 10(4) kpa (5500 psi) and 50 degrees C. Samples were held in static extraction for 10 min, followed by a dynamic extraction for 90 min at the flow rate of 1 mL/min. A simple and sensitive HPLC method was developed for the analysis of hyperforin and adhyperforin, the major phloroglucinols, in the SFE extract of SJW.  相似文献   

Hormone therapy: physiological complexity belies therapeutic simplicity     

Turgeon JL  McDonnell DP  Martin KA  Wise PM 《Science (New York, N.Y.)》2004,304(5675):1269-1273

The results of the Women's Health Initiative, a study anticipated to provide definitive answers about health benefits and risks of postmenopausal hormone therapy, have generated debate and confusion among clinicians, researchers, and the lay public. The ovarian hormones estrogen and progesterone, which decline at menopause, normally elicit complex tissue-specific responses throughout the body. Major advances are providing a detailed molecular definition of how that differential action is achieved. Here we review estrogen and progestin actions, discuss how effectively knowledge of steroid hormone endocrinology has been incorporated into clinical studies, and consider the impact on modern hormone therapy protocols and pharmaceutical development.  相似文献