Studies on bacterial gene transposition

(1) Two Escherichia coli K12 based transposition frequency assay systems have been designed and developed to allow the frequency of prokaryotic transposable element movements to be simply assayed. One of these systems involves the giant transposon bacteriophage Mu dl(ApRlac), that carries the P-galactosidase gene so that insertion adjacent to promotors can be quantified. The other system developed involves transposon 5 (Tn5), initially inserted in the host genome, that encodes kanamycin resistance which allows transposition to (and amplification in) plasmids to be quantified. (2) The most transposogenic compounds identified in the two transposition frequency assays are the alkyl-nitro-nitrosoguanidine alkylating agents. Most other alkylating agents exam­ined were either weakly transposogenic or non-transposogenic. (3) The alkyl-nitro-nitrosoguanidines appear to act by guanylate cyclase activation, via nitroxide radical release, and subsequent elevation of the cGMP concentration. The transposogen- icity of cGMP is confirmed by an apparant effect of permeable cGMP derivatives on Mu d\(ApRlac) and Tn5 transposition frequency. (4) A group of metals were examined for transposogenicity, and showed that transposogeni- city may be related to mutagenicity since mutagenic metals (Cd(II), Cr(VI) and Mn(II)) are tran­sposogenic and an anti-mutagenic metal (Co(II)) is anti-transposogenic. (5) The majority of transposogens identified in the two transposition frequency assays were mutagens, well documented in literature, and the putative non-transposogens were non- mutagenic. However, one group of compounds investigated were three non-mutagenic (Ames test negative) carcinogens. Diethylstilbesuol, DDT and o-toluidine each gave increases in Mu d\{ApRlac) transposition frequency which, although weak effects, might not have been expected from the other data, which suggested that mutagenicity and transposogenicity are inter-connecte

Measuring Minimum Award Wage Reliance in Australia: The HILDA Survey Experience

An important group of interest for industrial tribunals in Australia is those workers who are reliant on awards for their pay and other employment conditions. Research on award reliance and its consequences, however, has long been hampered by the lack of good quality microdata. Most obviously, there are relatively few data sets in Australia that identify the method by which pay is set and also provide detailed information about individuals and the households in which they live. The HILDA Survey, however, is an exception to this, with information about award reliance, and methods of pay setting more generally, being collected for the first time in its 8th survey wave (in 2008). This paper reviews the quality of the data on award reliance that is being collected from this source. It then provides two examples of how these data can inform policy-relevant research questions: (i) to what extent are award-reliant workers found living in income-poor households; and (ii) what role does award reliance play in contributing to the gender pay gap? The results confirm that award-reliant workers are not especially concentrated in poor households, and that for award-reliant workers there is no evidence of any gender-based pay gap.Award reliance, Australia, gender pay equity, HILDA Survey, income distribution, minimum wages

Gender Differences in Rates of Job Dismissal: Why Are Men More Likely to Lose Their Jobs?

Empirical studies have consistently reported that rates of involuntary job separation, or dismissal, are significantly lower among female employees than among males. Only rarely, however, have the reasons for this differential been the subject of detailed investigation. In this paper, household panel survey data from Australia are used that also find higher dismissal rates among men than among women. This differential, however, largely disappears once controls for industry and occupation are included. These findings suggest that the observed gender differential primarily reflects systematic differences in the types of jobs into which men and women select.dismissals, gender differentials, involuntary job separations, HILDA Survey, Australia

Distribution, Abundance, and Biological Characteristics of Groundfish off the Coast of Washington, Oregon, and California, 1977-1986

We compare results of bottom trawl surveys off Washington, Oregon, and California in 1977, 1980, 1983, and 1986 to discern trends in population abundance, distribution, and biology. Catch per unit of effort, area-swept biomass estimates, and age and length compositions for 12 commercially important west coast groundfishes are presented to illustrate trends over the lO-year period. We discuss the precision, accuracy, and statistical significance of observed trends in abundance estimates. The influence of water temperature on the distribution of groundfishes is also briefly examined. Abundance estimates of canary rockfish, Sebastes pinniger, and yellowtail rockfish, S. Jlavidus, declined during the study period; greater declines were observed in Pacific ocean perch, S. alutus, lingcod, Ophiodon elongatus, and arrowtooth flounder, Atheresthes stomias. Biomass estimates of Pacific hake, Merluccius productus, and English, rex, and Dover soles (Pleuronectes vetulus, Errex zachirus, and Microstomus pacificus) increased, while bocaccio, S. paucispinis, and chilipepper, S. goodei, were stable. Sablefish, Anoplopoma fimbria, biomass estimates increased markedly from 1977 to 1980 and declined moderately thereafter. Precision was lowest for rockfishes, lingcod, and sablefish; it was highest for flatfishes because they were uniformly distributed. The accuracy of survey estimates could be gauged only for yellowtail and canary rockfish and sablefish. All fishery-based analyses produced much larger estimates of abundance than bottom trawl surveys-indicative of the true catchability of survey trawls. Population trends from all analyses compared well except in canary rockfish, the species that presents the greatest challenge to obtaining reasonable precision and one that casts doubts on the usefulness of bottom trawl surveys for estimating its abundance. (PDF file contains 78 pages.

Visual field changes following trabeculectomy

The use of automated visual fields to detect and monitor glaucoma is hampered by having no gold standard against which to compare them. In the case of monitoring disease progression visual fields display large amounts of fluctuation that can mask true change. The analysis of fields using pointwise linear regression (PLR) has been developed to more accurately detect change. However the criteria for change using PLR are themselves poorly understood. This thesis examines the collection of field data from a surgical trial of trabeculectomy and then explores the detection of change in the eyes in the study using conventional and PLR grading techniques. Analysis of field data from an initial group of patients in the trial reveals the large amount of change detected using existing criteria. Much of the change detected is due to noise or fluctuations in a patient's response that do not represent real change. The use of modified criteria has variable effects on the detection of change. From this group of modified criteria, 6 can be selected on an empirical basis. All maximise the detection of progression while minimising improvement. Given the data available it is not possible to link any changes in visual field to changes in media opacity, especially cataract. When the selected criteria are tested against a) extended follow up data and b) a second group of patients from the same trial one criterion offers the ability to detect progression in both groups of patients while minimising the detection of improvement. This criterion requires a particular spatial arrangement of points in the field. Analysing groups of patients' fields using PLR without regard to treatment offers a way of developing change criteria prior to analysis within treatment arms

Cellulase immobilization on superparamagnetic nanoparticles for reuse in cellulosic biomass conversion

Current cellulosic biomass hydrolysis is based on the one-time use of cellulases. Cellulases immobilized on magnetic nanocarriers offer the advantages of magnetic separation and repeated use for continuous hydrolysis. Most immobilization methods focus on only one type of cellulase. Here, we report co-immobilization of two types of cellulases, β-glucosidase A (BglA) and cellobiohydrolase D (CelD), on sub-20 nm superparamagnetic nanoparticles. The nanoparticles demonstrated 100% immobilization efficiency for both BglA and CelD. The total enzyme activities of immobilized BglA and CelD were up to 67.1% and 41.5% of that of the free cellulases, respectively. The immobilized BglA and CelD each retained about 85% and 43% of the initial immobilized enzyme activities after being recycled 3 and 10 times, respectively. The effects of pH and temperature on the immobilized cellulases were also investigated. Co-immobilization of BglA and CelD on MNPs is a promising strategy to promote synergistic action of cellulases while lowering enzyme consumption

Biology and Management of Sablefish, Anoplopoma fimbria: Papers from the International Symposium on the Biology and Management of Sablefish, Seattle, Washington, 13-15 April 1993

At its june 1990 annual meeting, the Technical Subcommittee (TSC) of the Canada-U.S. Groundfish Committee recommended that scientists and managers working on sablefish, Anoplopoma fimbria, issues convene to present and discuss the results of their recent research. Thorough knowledge of the biology and population dynamics of this species is essential for its effective management, especially considering its commercial importance. TSC representatives from both countries recognized that a great deal ofactive research has been conducted on this species since the International Sablefish Symposium was held in Anchorage, Alaska, in March 1983 (Melteff, 1983). As a result of this recommendation, the International Symposium on the Biology and Management of Sablefish (ISBMS) was convened April 13-15, 1993, at the Alaska Fisheries Science Center in Seattle, Washington. (PDF file contains 286 pages.

Initial experience using a femtosecond laser cataract surgery system at a UK National Health Service cataract surgery day care centre

© 2019 The Author(s). This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/OBJECTIVES: To describe the initial outcomes following installation of a cataract surgery laser system.SETTING: National Health Service cataract surgery day care unit in North London, UK.PARTICIPANTS: 158 eyes of 150 patients undergoing laser-assisted cataract surgery.INTERVENTIONS: Laser cataract surgery using the AMO Catalys femtosecond laser platform.PRIMARY AND SECONDARY OUTCOME MEASURES: PRIMARY OUTCOME MEASURE: intraoperative complications including anterior and posterior capsule tears.SECONDARY OUTCOME MEASURES: docking to the laser platform, successful treatment delivery, postoperative visual acuities.RESULTS: Mean case age was 67.7±10.8 years (range 29-88 years). Docking was successful in 94% (148/158 cases), and in 4% (6/148 cases) of these, the laser delivery was aborted part way during delivery due to patient movement. A total of 32 surgeons, of grades from junior trainee to consultant, performed the surgeries. Median case number per surgeon was 3 (range from 1-20). The anterior capsulotomy was complete in 99.3% of cases, there were no anterior capsule tears (0%). There were 3 cases with posterior capsule rupture requiring anterior vitrectomy, and 1 with zonular dialysis requiring anterior vitrectomy (4/148 eyes, 2.7%). These 4 cases were performed by trainee surgeons, and were either their first laser cataract surgery (2 surgeons) or their first and second laser cataract surgeries (1 surgeon).CONCLUSIONS: Despite the learning curve, docking and laser delivery were successfully performed in almost all cases, and surgical complication rates and visual outcomes were similar to those expected based on national data. Complications were predominately confined to trainee surgeons, and with the exception of intraoperative pupil constriction appeared unrelated to the laser-performed steps.Peer reviewe

Switchgrass storage effects on the recovery of carbohydrates after liquid hot water pretreatment and enzymatic hydrolysis

Perennial grasses that would be used for bioenergy and bioproducts production will need to be stored for various periods of time to ensure a continual feedstock supply to a bioprocessing facility. The effects of storage practices on grass composition and the response of grasses to subsequent bioprocesses such as pretreatment and enzymatic hydrolysis needs to be understood to develop the most efficient storage protocols. This study examined the effect of outdoor storage of round switchgrass bales on composition before and after liquid hot water pretreatment (LHW) and enzymatic hydrolysis. This study also examined the effect of washing LHW pretreated biomass prior to enzymatic hydrolysis. It was determined that switchgrass composition after baling was stable. As expected, glucan and lignin contents increased after LHW due to decreases in xylan and galactan. Washing biomass prior to enzymatic hydrolysis reduced saccharification, especially in samples from the interior of the bale, by at least 5%