The disposition of benzo(a)pyrene in the periphyton communities of two South Carolina streams: uptake and biotransformation

1982 ◽  
Vol 60 (10) ◽  
pp. 2084-2091 ◽  
Author(s):  
Mary G. Bruno ◽  
Timothy E. Fannin ◽  
Gordon J. Leversee
Keyword(s):  
South Carolina ◽  
Slide Surface ◽  
Uptake Rates ◽  
Area Basis ◽  
Autoradiographic Analysis ◽  
Colonization Time ◽  
Microscope Slides ◽  
Surface Area Basis ◽  
Glass Microscope ◽  
Sheath Material

The effect of periphyton community composition and colonization time on the uptake and biotransformation of benzo(a)pyrene (BaP) was determined in laboratory studies. Naturally colonized glass microscope slides were collected after 3 and 6 weeks from Castor Creek, which has a predominantly desmid flora, and after 3 and 5 weeks from diatom-dominated Upper Three Runs Creek. When expressed on a slide surface-area basis, the Castor Creek periphyton showed significantly greater BaP uptake rates at both colonization periods. Within streams, uptake rates increased significantly with colonization time. Autoradiographic analysis suggests that BaP was accumulated by surface sorption, especially to gelatinous sheath material. Active biotransformation as measured by the percentage extractable non-BaP 14C was not detected in either community.

Photolytic degradation of 2,4-D onZea maysleaves

Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 262-269 ◽  
Author(s):  
Ramarao Venkatesh ◽  
S. Kent Harrison
Keyword(s):  
Zea Mays ◽  
Time Course ◽  
Uv Light ◽  
Light Regime ◽  
Growth Chamber ◽  
Polychromatic Light ◽  
Photolytic Degradation ◽  
Microscope Slides ◽  
Glass Microscope

Growth chamber experiments were conducted to determine the effects of UV light and riboflavin on photolysis of 2,4-D applied toZea maysleaves. Droplets of 100 mg L−114C-2,4-D were applied toZ. maysleaves with and without 10 mg L−13H-riboflavin and exposed to either UV-enhanced or UV-attenuated polychromatic light in a time-course assay. Photolysis of nonabsorbed14C-2,4-D residues onZ. maysleaves was sensitized by riboflavin regardless of UV light regime, but a larger percentage of nonabsorbed herbicide was degraded under UV-enhanced light compared to UV-attenuated light. Riboflavin was almost completely photolyzed during the first 10 h of exposure; yet, photolysis of14C-2,4-D surface residues in treatments containing riboflavin increased from 59% at 10 h of exposure to 87% at 42 h of exposure. In corresponding treatments without riboflavin, photolysis of14C-2,4-D surface residues was 37% at 10 h of exposure and 84% at 42 h of exposure. In contrast, only 7% of the14C-2,4-D deposited on glass microscope slides was degraded after 42 h of exposure in the absence of riboflavin, whereas 59% was degraded in the presence of riboflavin. Photolysis of 2,4-D onZ. maysleaves in treatments without riboflavin suggests that certain epicuticular component(s) ofZ. maysacted as photosensitizers or catalytic agents that promoted photolysis of nonabsorbed 2,4-D residues.

scholarly journals Botryosphaeriaceae Species Spore-Trapping Studies in California Vineyards

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 717-724 ◽  
Author(s):  
J. R. Úrbez-Torres ◽  
M. Battany ◽  
L. J. Bettiga ◽  
C. Gispert ◽  
G. McGourty ◽  
...  
Keyword(s):  
Strong Relationship ◽  
Early Spring ◽  
Seasonal Abundance ◽  
Petroleum Jelly ◽  
Riverside County ◽  
Spore Release ◽  
Spore Trapping ◽  
Rain Events ◽  
Microscope Slides ◽  
Glass Microscope

The seasonal abundance of Botryosphaeriaceae spp. spores was studied in California vineyards by using glass microscope slides covered with petroleum jelly placed on grapevine cordons and Burkard volumetric spore traps at seven and two different locations, respectively. Correlation analysis was used to determine which meteorological variables (precipitation, relative humidity, temperature, and wind speed) influenced Botryosphaeriaceae spp. spore release. Among all variables, regression analysis resulted in a strong relationship between spore release and precipitation. Additionally, a positive relationship between irrigation and spore release was also observed in the Riverside County vineyard. During the study period, spore discharge of Botryosphaeriaceae spp. occurred from the first fall rain through the last spring rains, coinciding with September to April. However, based on the results obtained from the spore traps, most spores (over 60%) were trapped following rain events during the winter months of December, January, and February, which coincides with the grapevine pruning season. Botryosphaeriaceae spp. spore release was much lower in fall and early spring (22%) and very few or no spores were trapped in late spring and summer (3%). This work suggests that a delay of pruning time in California may be warranted to reduce grapevine infection because the current timing coincides with the greatest period of spore discharge.

scholarly journals A mammary gland whole mount technique that preserves cell fine structure for electron miscroscopy.

1979 ◽  
Vol 27 (9) ◽  
pp. 1271-1274 ◽  
Author(s):  
J M Strum
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Fine Structure ◽  
Mammary Gland ◽  
Trypan Blue ◽  
Negative Image ◽  
Whole Mount ◽  
Microscope Slides ◽  
Glass Microscope ◽  
Unusual Finding

A mammary gland whole mount technique has been developed that preserves cell fine structure and makes it possible to also examine the preparations by electron microscopy. The glands are placed on glass microscope slides, fixed in a paraformaldehyde-glutaraldehyde mixture, defatted in acetone, stained with 0.5% methylene blue (or trypan blue) in saline, and dehydrated in ethanol. They are evaluated and photographed in 100% ethanol. Then specific areas (i.e. containing small growths, tumors, or other lesions) are selected, excised and prepared for electroscopy. The ultrastructural preservation is good, organelles are evident and there is no observable dye precipitate. The only unusual finding is that cell membranes display a "negative" image.

Catalytic Activity and Surface Characterization Study of Pd Supported on Nanocrystalline and Polycrystalline CeO2

1999 ◽  
Vol 581 ◽  
Author(s):  
Gar B. Hoflund ◽  
Zhenhua Li ◽  
Timothy J. Campbell ◽  
William S. Epling ◽  
Horst W. Hahn
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Surface Concentration ◽  
Slow Step ◽  
Activity Increase ◽  
Area Basis ◽  
Surface Area Basis ◽  
Supported Pd

ABSTRACTThe catalytic activity of polycrystalline and nanocrystalline CeO2-supported Pd (Pd/pCeO2 and Pd/nCeO2) has been determined as a function of temperature and Pd loading. While the untreated nCeO2 support gives 50% methane conversion at 420°C, the untreated pCeO2 support exhibits little activity under the conditions examined due to its low surface area. A Pd loading of 5 wt% increases the activity of pCeO2 to 50% conversion at 260°C, while a 40 wt% Pd loading on nCeO2 exhibits a relatively smaller activity increase, yielding 50% conversion at 240°C. On a mass basis the 40 wt% Pd/nCeO2 catalyst is the most active tested in this study, but it is less active than the 5 wt% Pd/pCeO2 catalyst on a surface-area basis. Furthermore, the activity of the 40 wt% Pd/nCeO2 catalyst does not decrease during 100 hrs of exposure to CH4 and O2 at 250°C.X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) have been used to characterize the surfaces of both bare supports and Pd-containing catalysts before and after exposure to reactor conditions. The XPS results reveal that the Pd surface concentration is more than an order of magnitude higher for 5 wt% Pd/pCeO2 than for 5 wt% Pd/nCeO2 due to the larger surface area of nCeO2 and that the 40 wt% Pd/nCeO2 catalyst has a lower Pd loading on a surface-area basis than the 5 wt% Pd/pCeO2 catalyst. Most of the supported Pd is in the form of PdO, but higher PdO2/PdO ratios are observed for both CeO2 supports compared to Pd supported on ZrO2 or CO3O4. Furthermore, a significant amount of metallic Pd forms on Pd/nCeO2 but not on Pd/pCeO2 during reaction. The nanocrystalline and polycrystalline CeO2 behave differently chemically which is consistent with the fact that the nanocrystalline catalysts are less active on a surface-area basis. Accumulation of H20 on the Pd/pCeO2 surface during reaction is significant but not on the Pd/nCeO2 surface. This suggests that the rate limiting step may be H2O desorption on Pd/pCeO2 while for Pd on nCeO2 adsorption of methane appears to be the slow step. The ISS data indicate that the outermost atomic layer of Pd/nCeO2 consists mostly of O and C, which is not the case for Pd/pCeO2. Site blockage by these species may also contribute to the lower activity on a surface-area basis of Pd/nCeO2 compared to Pd/pCeO2.

Quantitative assessment of the bacterial rhizosphere flora of Pinus contorta var. latifolia

1975 ◽  
Vol 21 (12) ◽  
pp. 2034-2038 ◽  
Author(s):  
J. A. Dangerfield ◽  
D. W. S. Westlake ◽  
F. D. Cook
Keyword(s):  
Pinus Contorta ◽  
Quantitative Assessment ◽  
Rhizosphere Soil ◽  
Bacterial Flora ◽  
Root Systems ◽  
Control Soil ◽  
Root Radius ◽  
Area Basis ◽  
Soil Rhizosphere ◽  
Surface Area Basis

The bacterial flora associated with root systems of young and mature lodgepole pine was investigated by sampling forest-grown trees. Counts were performed and expressed on a surface-area basis to give a more realistic comparison of organism density or activity within the control soil, rhizosphere soil, and rhizoplane. On this basis, densities increased by an order of 104- to 106-fold from control soil to rhizoplane, with the degree of stimulation being inversely related to root radius.

Ectomycorrhizal fungi of Salix rotundifolia III. Resynthesized mycorrhizal complexes and their surface phosphatase activities

1981 ◽  
Vol 59 (12) ◽  
pp. 2458-2465 ◽  
Author(s):  
R. K. Antibus ◽  
J. G. Croxdale ◽  
O. K. Miller ◽  
A. E. Linkins
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Ectomycorrhizal Fungi ◽  
Environmental Conditions ◽  
Pure Culture ◽  
Acid Phosphatase Activity ◽  
Cenococcum Geophilum ◽  
Nitrophenyl Phosphate ◽  
Area Basis ◽  
Surface Area Basis

Pure culture isolates were obtained from fungi fruiting in the vicinity of dwarf willows at Barrow and Cape Simpson, Alaska. Four of these isolates and one isolate from Maryland were tested for their ability to form ectomycorrhizae with cuttings of Salix rotundifolia under controlled environmental conditions. Isolates of Entoloma sericeum, Hebelomapusillum, and Cenococcum geophilum from Barrow and Cape Simpson, Alaska all formed typical ectomycorrhizae with S. rotundifolia, while an isolate of C. geophilum from a temperate ecosystem (Maryland) did not.All of the ectomycorrhizae synthesized with S. rotundifolia, plus uncolonized roots, demonstrated an ability to hydrolyze p-nitrophenyl phosphate at a pH of 4.7. The acid phosphatase activity of E. sericeum ectomycorrhizae was from 10 to 40 times as great as that demonstrated by other mycorrhizal and nonmycorrhizal roots on a surface area basis.

The respiratory metabolism of parasitic nematodes

Parasitology ◽  
1948 ◽  
Vol 39 (1-2) ◽  
pp. 105-109 ◽  
Author(s):  
W. P. Rogers
Keyword(s):  
Haemonchus Contortus ◽  
Potassium Cyanide ◽  
The Other ◽  
Parasitic Nematodes ◽  
Ascaridia Galli ◽  
Reserve Material ◽  
Infective Larvae ◽  
Third Stage ◽  
Area Basis ◽  
Surface Area Basis

1. Qo2 values for Haemonchus contortus egs varied between − 9·7 and − 12·6 according to the degree of development of the embryos. The r.q. was in the region of 0·6.2. Young infective larvae of Nippostrongylus muris had a high Qo2 (−18·4), which fell as the larvae aged. Third stage Haemonchus contortus larvae gave similar results. The respiration was not affected by exsheathment.3. Adult parasites gave Qo2 values as follows: Ascaridia galli, − 2·5; Nematodirus spp., − 5·1; Nippostrongylus muris, − 6·8; Neoaplectana glaseri, − 12·6. When calculated on a surface area basis, Ascaridia galli had an oxygen uptake which was much higher than that of the other organisms.4. Qco2 values were small. The r.q. of infective larvae, which contain fat as reserve material, was about 0·72. The other forms which contained much glycogen as well as fat had r.q. values between 0·6 and 0·7. A. galli was an exception in that an r.q. of about 0·95 was obtained.5. Potassium cyanide inhibited respiration in all the forms examined.The author is indebted to Dr R. W. Glaser for supplying a strain of Neoaplectana glaseri.

scholarly journals Development of a rapid diagnostic test for the detection of antibodies or antigens to Coronavirus (COVID-19)

2021 ◽  
Author(s):  
James Elliff
Keyword(s):  
Low Income ◽  
Rapid Detection ◽  
Spike Protein ◽  
Low Income Countries ◽  
Health Crisis ◽  
Significant Difference ◽  
Specific Antigens ◽  
Microscope Slides ◽  
Glass Microscope ◽  
Control Samples

Theglobal health crisis caused by COVID-19 has overwhelmed both healthcaresettings and economies globally. Whilst mass population testing has improveddrastically, recent reviews of existing methods have highlighted variousshortcomings with these methods. Theaim of this project was to investigate whether the LAA could be modified andutilised as rapid detection test which either matched or exceeded the existingsensitivity and specificity values.   TheLAA investigated whether the COVID-19 spike protein could be detected insamples. COVID-19 specific IgM and IgG were used in conjunction with a seriesof non-specific antigens. Control or AG containing samples weremixed with AB-microsphere complexes on glass microscope slides. Manualvisualisation identified various levels of agglutination. Light microscopy andspectrophotometry at 405nm determined that the LAA could detect at least 2.3ngof spike protein.  Theparticle counting tool of ImageJ was utilised to obtain a dataset which wassubjected to statistical analysis which indicated that there was a significantdifference between control samples and live tests, P = 0.000102 for the spikeprotein assay and P = 0.254 for the non-specific assay respectively. Theresults obtained fell in line with a similar study conducted by Buffin et al in2018. Theanalytical methods used in this project twinned with data obtained in previousstudies supports the significant difference between control values and livetest values. The LAA is easier, quicker to use (results in ≤ 30 minutes) andcheaper, with potentially better sensitivity to existing methods. This couldbenefit high and low-income countries alike upon further research andoptimisation. 

Reactions between boron and clays

Soil Research ◽  
1964 ◽  
Vol 2 (1) ◽  
pp. 83 ◽  
Author(s):  
FJ Hingston
Keyword(s):  
Boric Acid ◽  
Surface Area ◽  
Total Surface Area ◽  
Langmuir Equation ◽  
Adsorbed Species ◽  
Mannitol Solution ◽  
Clay Surface ◽  
Ph Values ◽  
Area Basis ◽  
Surface Area Basis

Sorption of boron by Kent sand kaolinite, WilIalooka illite, and Marchagee montmorillonite in 0.01M CaCl2 is consistent with a mechanism described by the Langmuir equation, except that deviations occur at solution concentrations greater than about 10 �g B/ml. The quantity of boron adsorbed increases markedly with pH, and is rapid, reversible, and unaffected by the concentration of calcium chloride present. Complete desorption of surface boron, without significant solution of lattice boron, is achieved with 0.01M mannitol solution. Comparing the three clays at pH 7.5 on a surface area basis, the illite is most reactive (1.18 �g B/m2), followed by the kaolinite (0.28 �g B/m2) and the montmorillonite (0.02 �g B/m2). For illite, which is the most reactive of the three minerals, the magnitude of the above values emphasizes the small proportion (less than 1.4%) of the total surface area occupied by boron. Consideration of the reaction between boron and clays suggests that either boric acid molecules or borate ions could be the adsorbed species. Increasing sorption with pH could be explained either by the increasing proportion of borate ions to boric acid with pH or by a greater number of sites on the clay surface at higher pH values.

scholarly journals Optimization of the binding of dissociated exfoliated cervico-vaginal cells to glass microscope slides.

1977 ◽  
Vol 25 (7) ◽  
pp. 538-543 ◽  
Author(s):  
R C Leif ◽  
D Ingram ◽  
C Clay ◽  
D Bobbitt ◽  
R Gaddis ◽  
...  
Keyword(s):  
The Other ◽  
Centrifugal Field ◽  
Bonding Agents ◽  
Cell Dissociation ◽  
Silicone Coating ◽  
Glass Slides ◽  
Acceleration And Deceleration ◽  
A Cell ◽  
Microscope Slides ◽  
Glass Microscope

In order to monitor the development of a cell dissociation technique, it was essential to utilize the Centrifugal Cytology rotor to produce glutaraldehyde-fixed even cellular dispersions. The Cytology rotor has been improved to insure rapid alignment with the centrifugal field during both acceleration and deceleration, and the fixative is now delivered to the surface of the slide. The dissociation of the cells results in a loss of their adhesion to glass slides. Three bonding agents were tested: (a) Poly-L-Lysine; (b) Mayer's albumin fixative; (c) positively charging the slides with a silicone coating. The results with 65% albumin-coated slides were clearly superior to the other two. The addition of a postfixation step of 95% ethanol/4% polyethylene glycol did not significantly affect the recovery of the cells, but did eliminate some unevenness in the Centrifugal Cytology preparations, flattened the cells and expedited the procedure.

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