Persistence pays off: Sir Charles Oatley and the scanning electron microscope

Shortly after World War II, Sir Charles Oatley initiated research at the Cambridge University engineering laboratories on what has evolved into the modern scanning electron microscope. While much of the research was actually conducted by research students under Oatley's supervision, he continually provided ideas, resources, and encouragement. He then was instrumental in having this instrument commercialized. His students often continued in the field for some time, making contributions both to the instrument and to its applications that led to improved performance and wider acceptance. This article attempts to capture some of the accomplishments of Sir Charles Oatley as seen by those who worked closely with him. The author believes that Sir Charles deserves the title: "Father of the Modern Scanning Electron Microscope.

The clinical pharmacology of intranasal l-methamphetamine.

BackgroundWe studied the pharmacology of l-methamphetamine, the less abused isomer, when used as a nasal decongestant.Methods12 subjects self-administered l-methamphetamine from a nonprescription inhaler at the recommended dose (16 inhalations over 6 hours) then at 2 and 4 (32 and 64 inhalations) times this dose. In a separate session intravenous phenylephrine (200 microg) and l-methamphetamine (5 mg) were given to define alpha agonist pharmacology and bioavailability. Physiological, cardiovascular, pharmacokinetic, and subjective effects were measured.ResultsPlasma l-methamphetamine levels were often below the level of quantification so bioavailability was estimated by comparing urinary excretion of the intravenous and inhaled doses, yielding delivered dose estimates of 74.0 +/- 56.1, 124.7 +/- 106.6, and 268.1 +/- 220.5 microg for ascending exposures (mean 4.2 +/- 3.3 microg/inhalation). Physiological changes were minimal and not dose-dependent. Small decreases in stroke volume and cardiac output suggesting mild cardiodepression were seen.ConclusionInhaled l-methamphetamine delivered from a non-prescription product produced minimal effects but may be a cardiodepressant

Spatial Patterns of Brown Rot Epidemics and Development of Microsatellite Markers for Analyzing Fine-Scale Genetic Structure of \u3ci\u3eMonilinia fructicola\u3c/i\u3e Populations Within Peach Tree Canopies

To better understand the fine-scale spatial dynamics of brown rot disease and corresponding fungal genotypes, we analyzed three-dimensional spatial patterns of pre-harvest fruit rot caused by Monilinia fructicola in individual peach tree canopies and developed microsatellite markers for canopy-level population genetics analyses. Using a magnetic digitizer, high-resolution maps of fruit rot development in five representative trees were generated, and M. fructicola was isolated from each affected fruit. To characterize disease aggregation, nearest-neighbor distances among symptomatic fruit were calculated and compared with appropriate random simulations. Within-canopy disease aggregation correlated negatively with the number of diseased fruit per tree (r = −0.827, P = 0.0009), i.e., aggregation was greatest when the number of diseased fruit was lowest. Sixteen microsatellite primers consistently amplified polymorphic regions in a geographically diverse test population of 47 M. fructicola isolates. None of the test isolates produced identical multilocus genotypes, and the number of alleles per locus ranged from 2 to 16. We are applying these markers to determine fine-scale population structure of the pathogen within and among canopies

Spatial Patterns of Brown Rot Epidemics and Development of Microsatellite Markers for Analyzing Fine-Scale Genetic Structure of \u3ci\u3eMonilinia fructicola\u3c/i\u3e Populations Within Peach Tree Canopies

To better understand the fine-scale spatial dynamics of brown rot disease and corresponding fungal genotypes, we analyzed three-dimensional spatial patterns of pre-harvest fruit rot caused by Monilinia fructicola in individual peach tree canopies and developed microsatellite markers for canopy-level population genetics analyses. Using a magnetic digitizer, high-resolution maps of fruit rot development in five representative trees were generated, and M. fructicola was isolated from each affected fruit. To characterize disease aggregation, nearest-neighbor distances among symptomatic fruit were calculated and compared with appropriate random simulations. Within-canopy disease aggregation correlated negatively with the number of diseased fruit per tree (r = −0.827, P = 0.0009), i.e., aggregation was greatest when the number of diseased fruit was lowest. Sixteen microsatellite primers consistently amplified polymorphic regions in a geographically diverse test population of 47 M. fructicola isolates. None of the test isolates produced identical multilocus genotypes, and the number of alleles per locus ranged from 2 to 16. We are applying these markers to determine fine-scale population structure of the pathogen within and among canopies

Characterization of \u3ci\u3eNeofabraea actinidiae\u3c/i\u3e and \u3ci\u3eN. brasiliensis\u3c/i\u3e as causal agents of apple bull’s-eye rot in southern Brazil

The causal agents of apple bull’s-eye rot in southern Brazil have recently been described as Neofabraea actinidiae and N. brasiliensis. Isolates of both species were evaluated for response of mycelial growth index (MGI) to different temperatures, enzyme production, mycelial growth inhibition and effective concentrations (EC50 and EC100) of the fungicides triflumizole, pyrimethanil and thiophanate methyl, as well as aggressiveness on fruits of ‘Fuji’ hybrid and ‘Pink Lady’. There was significantly lower mycelium growth in N. brasiliensis compared with N. actinidiae at all temperatures tested. Neither species grew at 3 and 32°C. There were minor differences in production of enzymes in the two species, with all N. brasiliensis isolates showing no production of pectolyase at pH 7. The lowest EC50 and EC100 values were observed with thiophanate methyl. In general, ‘Fuji’ fruits were more susceptible to Neofabraea infection and had larger lesions, while N. brasiliensis isolates showed greater aggressiveness on ‘Fuji’ hybrid and ‘Pink lady’ fruits compared with N. actinidiae. Dans le sud du Brésil, les agents causaux du chancre gloésporien de la pomme ont récemment été décrits comme étant Neofabraea actinidiae et N. brasiliensis. Des isolats des deux espèces ont été évalués en fonction de la réaction de l’indice de croissance mycélienne à différentes températures, de la production enzymatique, de l’inhibition de la croissance mycélienne et des concentrations efficaces (CE50 et CE100) des fongicides triflumizole, pyriméthanil et triophanate méthyle, ainsi qu’en fonction de leur agressivité à l’égard de la pomme hybride Fuji et de la Pink Lady. La croissance mycélienne chez N. brasiliensis était considérablement plus faible que chez N. actinidiae, et ce, à toutes les températures testées. Aucune espèce ne s’est développée à 3 ou à 32°C. Chez les deux espèces, il y a eu de petites différences quant à la production enzymatique, tous les isolats de N. brasiliensis n’affichant aucune production de pectolyase à pH 7. Les plus faibles valeurs de CE50 et de CE100 observées ont été celles du triophanate méthyle. Dans l’ensemble, les Fuji étaient plus sujettes à l’infection causée par Neofabraea et affichaient des lésions plus étendues, tandis que les isolats de N. brasiliensis étaient plus agressifs à l’égard de l’hybride Fuji et de la Pink Lady que ceux de N. actinidiae

Characterization of \u3ci\u3eNeofabraea actinidiae\u3c/i\u3e and \u3ci\u3eN. brasiliensis\u3c/i\u3e as causal agents of apple bull’s-eye rot in southern Brazil

The causal agents of apple bull’s-eye rot in southern Brazil have recently been described as Neofabraea actinidiae and N. brasiliensis. Isolates of both species were evaluated for response of mycelial growth index (MGI) to different temperatures, enzyme production, mycelial growth inhibition and effective concentrations (EC50 and EC100) of the fungicides triflumizole, pyrimethanil and thiophanate methyl, as well as aggressiveness on fruits of ‘Fuji’ hybrid and ‘Pink Lady’. There was significantly lower mycelium growth in N. brasiliensis compared with N. actinidiae at all temperatures tested. Neither species grew at 3 and 32°C. There were minor differences in production of enzymes in the two species, with all N. brasiliensis isolates showing no production of pectolyase at pH 7. The lowest EC50 and EC100 values were observed with thiophanate methyl. In general, ‘Fuji’ fruits were more susceptible to Neofabraea infection and had larger lesions, while N. brasiliensis isolates showed greater aggressiveness on ‘Fuji’ hybrid and ‘Pink lady’ fruits compared with N. actinidiae. Dans le sud du Brésil, les agents causaux du chancre gloésporien de la pomme ont récemment été décrits comme étant Neofabraea actinidiae et N. brasiliensis. Des isolats des deux espèces ont été évalués en fonction de la réaction de l’indice de croissance mycélienne à différentes températures, de la production enzymatique, de l’inhibition de la croissance mycélienne et des concentrations efficaces (CE50 et CE100) des fongicides triflumizole, pyriméthanil et triophanate méthyle, ainsi qu’en fonction de leur agressivité à l’égard de la pomme hybride Fuji et de la Pink Lady. La croissance mycélienne chez N. brasiliensis était considérablement plus faible que chez N. actinidiae, et ce, à toutes les températures testées. Aucune espèce ne s’est développée à 3 ou à 32°C. Chez les deux espèces, il y a eu de petites différences quant à la production enzymatique, tous les isolats de N. brasiliensis n’affichant aucune production de pectolyase à pH 7. Les plus faibles valeurs de CE50 et de CE100 observées ont été celles du triophanate méthyle. Dans l’ensemble, les Fuji étaient plus sujettes à l’infection causée par Neofabraea et affichaient des lésions plus étendues, tandis que les isolats de N. brasiliensis étaient plus agressifs à l’égard de l’hybride Fuji et de la Pink Lady que ceux de N. actinidiae

Characterization of Neofabraea actinidiae and N. brasiliensis as causal agents of apple bull's-eye rot in southern Brazil.

The causal agents of apple bull?s-eye rot in southern Brazil have recently been described as Neofabraea actinidiae and N. brasiliensis. Isolates of both species were evaluated for response of mycelial growth index (MGI) to different temperatures, enzyme production, mycelial growth inhibition and effective concentrations (EC 50 and EC 100 ) of the fungicides tri fl umizole, pyrimethanil and thiophanate methyl, as well as aggres- siveness on fruits of "Fuji " hybrid and " Pink Lady " . There was signi ficantly lower mycelium growth in N. brasiliensis compared with N. actinidiae at all temperatures tested. Neither species grew at 3 and 32°C. There were minor differences in production of enzymes in the two species, with all N. brasiliensis isolates showing no production of pectolyase at pH 7. The lowest EC 50 and EC 100 values were observed with thiophanate methyl. In general, " Fuji " fruits were more susceptible to Neofabraea infection and had larger lesions, while N. brasiliensis isolates showed greater aggressiveness on " Fuji " hybrid and " Pink lady " fruits compared with N. actinidiae

Aero-Heating of Shallow Cavities in Hypersonic Freestream Flow

The purpose of these experiments and analysis was to augment the heating database and tools used for assessment of impact-induced shallow-cavity damage to the thermal protection system of the Space Shuttle Orbiter. The effect of length and depth on the local heating disturbance of rectangular cavities tested at hypersonic freestream conditions has been globally assessed using the two-color phosphor thermography method. These rapid-response experiments were conducted in the Langley 31-Inch Mach 10 Tunnel and were initiated immediately prior to the launch of STS-114, the initial flight in the Space Shuttle Return-To-Flight Program, and continued during the first week of the mission. Previously-designed and numerically-characterized blunted-nose baseline flat plates were used as the test surfaces. Three-dimensional computational predictions of the entire model geometry were used as a check on the design process and the two-dimensional flow assumptions used for the data analysis. The experimental boundary layer state conditions were inferred using the measured heating distributions on a no-cavity test article. Two test plates were developed, each containing 4 equally-spaced spanwise-distributed cavities. The first test plate contained cavities with a constant length-to-depth ratio of 8 with design point depth-to-boundary-layer-thickness ratios of 0.1, 0.2, 0.35, and 0.5. The second test plate contained cavities with a constant design point depth-to-boundary-layer-thickness ratio of 0.35 with length-to-depth ratios of 8, 12, 16, and 20. Cavity design parameters and the test condition matrix were established using the computational predictions. Preliminary results indicate that the floor-averaged Bump Factor (local heating rate nondimensionalized by upstream reference) at the tested conditions is approximately 0.3 with a standard deviation of 0.04 for laminar-in/laminar-out conditions when the cavity length-to-boundary-layer thickness is between 2.5 and 10 and for cavities in the depth-to-boundary-layer-thickness range of 0.3 to 0.8. Over this same range of conditions and parameters, preliminary results also indicate that the maximum Bump Factor on the cavity centerline falls between 2.0 and 2.75, as long as the cavity-exit conditions remain laminar. Cavities with length-to-boundary-layer-thickness ratio less than 2.5 can not be easily classified with this approach and require further analysis