590 research outputs found
One-handed hammer-spanner for chucks
Modified spanner wrench with a heavy hammer-piece hinged to its handle allows one hand removal of a tool from a chuck
Antimicrobial activity of plant extracts
The purpose of this study was to investigate a possible antimicrobial activity in the following plants: Brunfelsia hopeana, Anemopsis californica, and Heimia salicifolia against Staphylococcus aureus, a Gram-positive coccus, Escherichia coli, a Gram-negative fermenter, Pseudomonas aeruginosa, a Gram-negative non-fermenter, and the yeast Candida albicans
Seasonal distributions of fine aerosol sulfate in the North American Arctic basin during TOPSE
We used the mist chamber/ion chromatography technique to quantify fine aerosol SO4=(\u3c2.7 μm) in the Arctic during the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) with about 2.5 min time resolution. Our effective sample area ranged from 50° to 86°N and 53° to 100°W. The seasonal evolution of fine aerosol sulfate in the Arctic troposphere during TOPSE was consistent with the phenomenon of Arctic haze. Arctic haze has been attributed to pollution from sources in the Arctic and pollution transported meridionally along stable isentropes into the Arctic in geographically broad but vertically narrow bands. These layers became more prevalent at higher altitudes as the season progressed toward summer, and the relevant isentropes are not held so close to the surface. Mean fine particle SO4= mixing ratios during TOPSE in February below 1000 m were elevated (112 pptv) and highly variable (between 28 and 290 pptv) but were significantly lower at higher altitudes (about 40 pptv). As the season progressed, elevated mixing ratios and higher variability were observed at higher altitudes, up to 7 km. In May, mixing ratios at the lowest altitudes declined but still remained higher than in February at all altitudes. The high variability in our measurements likely reflects the vertical heterogeneity of the wintertime Arctic atmosphere as the airborne sampling platform passed in and out of these layers. It is presumed that mixing ratios and variability will continue to decline at all altitudes into the summer as wet deposition processes become important in removing aerosol SO4= from the troposphere
Stratospheric influence on the northern North American free troposphere during TOPSE: 7Be as a stratospheric tracer
We use 7Be, with HNO3 and O3, to identify air masses sampled from the NCAR C-130 during TOPSE that retained clear evidence of stratospheric influence. A total of 43 such air masses, spread fairly evenly across the February to May sampling period, and 40°N–86°N latitude range, were encountered. South of 55°N, nearly all clear stratospheric influence was restricted to altitudes above 6 km. At higher latitudes stratospherically influenced air masses were encountered as low as 2 km. Approximately 12% of all TOPSE sampling time at altitudes above 2 km was spent in stratospherically impacted air, above 6 km this increased to more than half of the time. Because it is not certain how much of this stratospherically influenced air irreversibly injected mass (and chemical compounds) into the troposphere, we estimate the stratospheric fraction of O3 in high latitude TOPSE samples based on a linear relationship to7Be and compare it to in situ O3. This analysis indicates that the stratospheric source can account for a dominant fraction (\u3e85%) of in situ O3 throughout TOPSE, but that the stratospheric contribution was nearly constant through the 4 month campaign. In February and March the 7Be based estimates of stratospheric O3 account for 10–15% more O3 than was measured, but by April and May there is up to about 10% more O3 than expected from the stratospheric source. This trend suggests that a seasonal transition from O3 depletion to photochemical production in the high latitude North American troposphere is the major cause of the springtime increase in O3
Bedrock Geology of Kaskaskia Quadrangle, Randolph County, Illnois and Ste. Genevieve and Perry Counties, Missouri
Survey and identification of termites (Insecta, Isoptera) using morphological and molecular methods from eastern, central and western Ethiopia.
The subfamily Macrotermitinae are the largest members among the Family Termitidae which are the fungus growing sub-family and Odontotermes are the most abundant genus from the subfamily. The taxonomy of termites is poorly described in Ethiopia. In the present study 168 termite samples were collected from eight locations of Eastern, Western and Central Ethiopia. The collected samples were identified based on morphological and molecular characteristics. Molecular identification was done based on the dna sequence of a portion of the mitochondrial 16S rrna gene. A phylogenetic analysis of the collected samples and the outgroup resulted in a consensus tree with four distinct groups. Geographical distribution of the samples also supported the resulting clades. Odontotermes were the most widely distributed termites from the collected samples. The genetic distance between the sample showed that Odontotermes zambesiensis, Babile 33 is more distantly related with the rest of the samples
Investigations into free tropospheric new particle formation in the central Canadian arctic during the winter/spring transition as part of TOPSE
In this paper, we investigate the role of in situ new particle production in the central Canadian sub-Arctic and Arctic as part of the TOPSE experiment. Airborne measurements conducted primarily in the free troposphere were made from 50° to 90°W longitude and 60° to 85°N latitude during the period from February to May 2000. Data pertinent to this paper include 3–4 nm diameter (Dp) particles, ultrafine condensation nuclei (Dp \u3e 3 nm), fine particles (0.2 \u3c Dp \u3c 3 μm), and the possible nucleation precursor, sulfuric acid, and its precursor, sulfur dioxide. For data averaged over this period, most species showed little evidence for a latitudinal trend. Fine aerosol number concentrations, however, showed a slight increase with latitude. The evolution of various species concentrations over the period of the study show that fine particles also had a consistent temporal trend, increasing at all altitudes from February to May, whereas sulfur dioxide at the surface tended to peak in late March. Ultrafine condensation nuclei and 3–4 nm particles showed no temporal trends. Little evidence for in situ new particle production was observed during the study, except for one atypical event where SO2concentrations were 3.5 ppbv, 2 orders of magnitude higher than typical levels. This paper cannot address the question of whether the observed condensation nuclei were produced in situ by a low particle production rate or transported from lower latitudes
Level of protein kinase C activity correlates directly with resistance to adriamycin in murine fibrosarcoma cells
AbstractIn this report, we demonstrate a direct correlation between protein kinase C (PKC) activity and adriamycin (ADR) resistance in mouse fibrosarcoma cells. PKC activity was measured in four murine UV-2237M fibrosarcoma cell lines that differed in the degrees to which they expressed resistance to ADR, which is an inhibitor of PKC. A comparison of the four cell lines revealed a positive correlation between the level of PKC activity and resistance to ADR. Incubation of the cells with the PKC inhibitor H-7 produced a partial reversal of ADR resistance. Taken together, these results suggest a role for PKC in the mechanism of ADR resistance
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