Showing papers by "University of Queensland published in 1970"

Properties and regulation of leaf nicotinamide-adenine dinucleotide phosphate-malate dehydrogenase and 'malic' enzyme in plants with the C4-dicarboxylic acid pathway of photosynthesis.

Abstract: 1. NADP-malate dehydrogenase and ;malic' enzyme in maize leaf extracts were separated from NAD-malate dehydrogenase and their properties were examined. 2. The NADP-malate dehydrogenase was nicotinamide nucleotide-specific but otherwise catalysed a reaction comparable with that with the NAD-specific enzyme. By contrast with the latter enzyme, a thiol was absolutely essential for maintaining the activity of the NADP-malate dehydrogenase, and the initial velocity in the direction of malate formation, relative to the reverse direction, was faster. 3. For the ;malic' enzyme reaction the K(m) for malate was dependent on pH and the pH optimum varied with the malate concentration. At their respective optimum concentrations the maximum velocity for this enzyme was higher with Mg(2+) than with Mn(2+). 4. The NADP-malate dehydrogenase in green leaves was rapidly inactivated in the dark and was reactivated when plants were illuminated. Reactivation of the enzyme extracted from darkened leaves was achieved simply by adding a thiol compound. 5. The activity of both enzymes was low in etiolated leaves of maize plants grown in the dark but increased 10-20-fold, together with chlorophyll, when leaves were illuminated. 6. The activity of these enzymes in different species with the C(4)-dicarboxylic acid pathway was compared and their possible role in photosynthesis was considered.

On the sharpness of a limiting case of the Sobolev imbedding theorem

Abstract: A refinement of the Sobolev imbedding theorem, due to Trudinger, is shown to be optimal in a natural sense.

Neutrophils: Their Role in the Formation of a Tick Feeding Lesion

Abstract: Dogs infested with adtult Rhipicephalus sanguineus were given nitrogen mustard to reduce leukocyte numbers. In the treated animals the tick lesions were insignificant, lacking the collagen destruiction found in untreated hosts, bitt the ticks engorged normally. Feeding results from tick secretions causing vascitlar trauima and is independent of tissute damage associated with inflammatory responses.

Aspects of tetrazolium salt reduction relevant to quantitative histochemistry

Abstract: Uncertainty about the nature of the reduction products of ditetrazolium salts may have limited their use in quantitative histochemistry. Our studies have shown that under appropriate conditions pure Nitro-BT reduces through a red intermediate substance to a stable blue diformazan. Nitrobenzene was found to be a satisfactory solvent for this diformazan. The monotetrazolium INT may also be reduced to a formazan through an intermediate phase. The amounts of definitive formazan produced from both monotetrazolium and ditetrazolium salts may be influenced by the solubility of their intermediate reduction compounds in the systems in which reduction is occurring. The yield of definitive diformazan from Nitro-BT after chemical reduction, and after enzymatic reduction in liver homogenate and sections of a “mock” tissue, was not in linear proportion to the strength of reducing conditions; however, the yields of formazan from the monotetrazoliums INT and MTT were linear. This finding suggests that in quantitative histochemistry it is essential to calibrate reactions involving ditetrazolium reduction.

The Larval Development of Macrobrachium Australiense Holthuis, 1950 (Decapoda, Palaemonidae), Reared in the Laboratory

Abstract: Les stades larvaires de Macrobrachium australiense Holthuis, 1950 sont decrits et compares a ceux d'autres especes de Palaemonidae. Λί. australiense a une vie larvaire abregee de trois stades, s'etendant sur environ six jours avant que la metamorphose au premier stade post-larvaire n'ait lieu. En ce qui concerne le developpement larvaire, M. australiense appartiendrait a la deuxieme classe de Sollaud (1923) qui comprend les Palaemonidae d'eau douce a courte vie larvaire. Pourtant M. australiense produit un nombre relativement grand de petits oeufs, ce qui caracterise plutot les especes marines. Il est possible que ces observations indiquent que M. australiense n'est venu de l'estuaire a l'eau douce qu'a une epoque relativement recente.

The origin of scapolite in the regionally metamorphosed rocks of Mary Kathleen, Queensland, Australia

Abstract: Scapolite at Mary Kathleen (North-Western Queensland) occurs in calcareous and non-calcareous metapelites, acid and basic metavolcanics and metadolerites. Graphical treatment of the relationship between scapolite composition (Me%) and the host rock oxide ratios CaO/Na2O and Al2O3/(CaO + Na2O) reveals the following points: (a) The calcareous metapelites are also very sodic. (b) Scapolite in calcareous metapelites is more marialitic than that in low-calcium equivalents. (c) In graphs of Me% against CaO/Na2O and Al2O3/(CaO + Na2O) the metasediments and the metaigneous rocks show markedly different trends. It is concluded that scapolite in the metasediments originated by isochemical metamorphism of shales and marls containing evaporitic halite. The local abundance of halite was the main control on the composition and distribution of the scapolite, but the relative abundance of CaO and Na2O was a modifying factor. In the metaigneous rocks scapolite formed metasomatically during regional metamorphism by the introduction of volatile-rich fluids derived from the adjacent evaporitic sediments. The relative availability of CO2 and Cl2 again appears to have been the primary control on scapolite composition and may in turn have been controlled by bulk rock composition.

Sweating rate and the electrolyte content of skin secretions of Bos taurus and Bos indicus cross-bred cows

Abstract: Sweating rate and the electrolyte content of secretions from the skin of cattle have been measured on five Bos taurus and five B. indicus cross-bred cows by absorbing secretions into filter papers under polythene disks applied to shaved skin areas on the shoulder, sacral and lumbar regions for 5 min. The increase in weight of the filter paper was taken as a measure of sweating rate and the distilled water eluate from the filter paper was analysed for sodium and potassium. Animals were exposed for 4 h to air temperatures of 20-45 °C at 30% r.h. and for 5-7 h to air temperatures of 40 and 45 °C at 40% r.h. Estimated sweating rates were low by comparison with previously reported values, probably due to rising levels of humidity under the polythene disks during exposure to the skin. B. indicus cross-bred cows had higher sweating rates than B. taurus cows at high air temperatures but the difference between the groups was not significant statistically. Sweating rates were generally highest on the shoulder and lowest on the lumbar region. The amounts of sodium and potassium recovered from filter papers were small and very variable at low air temperatures but increased significantly with air temperature (P < 0.01). No significant differences in the amounts of electrolyte recovered from filter papers were recorded between the species groups or between different sites of collection. The secretions from cattle skin at high ambient temperatures contained at least four to five times as much potassium as sodium. Total sodium and potassium loss through the skin of these experimental animals at the highest ambient temperatures was estimated to be no more than 1-3 % of the sodium and potassium intake in the feed. Absorbing sweat on to filter paper as a method of measuring sweating rate and sweat composition is rather less satisfactory for use with cattle than with man.

The Burden of HIV/AIDS in Ethiopia from 1990 to 2016: Evidence from the Global Burden of Diseases 2016 Study.

Abstract: Background: The burden of HIV/AIDS in Ethiopia has not been comprehensively assessed over the last two decades. In this study, we used the 2016 Global Burden of Diseases, Injuries and Risk factors (GBD) data to analyze the incidence, prevalence, mortality and Disability-adjusted Life Years Lost (DALY) rates of Human Immunodeficiency Virus / Acquired Immune Deficiency Syndrome (HIV/AIDS) in Ethiopia over the last 26 years. Methods: The GBD 2016 used a wide range of data source for Ethiopia such as verbal autopsy (VA), surveys, reports of the Federal Ministry of Health and the United Nations (UN) and published scientific articles. The modified United Nations Programme on HIV/AIDS (UNAIDS) Spectrum model was used to estimate the incidence and mortality rates for HIV/AIDS. Results: In 2016, an estimated 36,990 new HIV infections (95% uncertainty interval [UI]: 8775-80262), 670,906 prevalent HIV cases (95% UI: 568,268-798,970) and 19,999 HIV deaths (95% UI: 16426-24412) occurred in Ethiopia. The HIV/AIDS incidence rate peaked in 1995 and declined by 6.3% annually for both sexes with a total reduction of 77% between 1990 and 2016. The annualized HIV/AIDS mortality rate reduction during 1990 to 2016 for both sexes was 0.4%. Conclusions: Ethiopia has achieved the 50% reduction of the incidence rate of HIV/AIDS based on the Millennium Development Goals (MDGs) target. However, the decline in HIV/AIDS mortality rate has been comparatively slow. The country should strengthen the HIV/AIDS detection and treatment programs at community level to achieve its targets during the Sustainable Development Program (SDGs)-era.

How assessment and reflection relate to more effective learning in adaptive management

Abstract: Assessment (an immediate evaluation of significance or performance) and reflection (a lengthy, deep consideration) should be important components of adaptive management leading to learning. In this paper we use a prototype adaptive cycle and feedback framework, which are related to some aspects of learning theory, to examine the extent to which assessment and reflection were applied in a series of studies and initiatives in the Kruger National Park. In addition to evaluating assessment and reflection, we also considered how the various contributing components of each case were inter-related to provide a holistic view of each initiative. Two other studies in the Kruger National Park, which have examined learning specifically, are also discussed. One of them suggests that in a complex environment, learning necessarily has a dual nature, with each component of seven contrasting pairs of the aspects of learning in partial tension with the other. We use these dualities to further probe assessment, reflection, inter-relatedness and learning in the cases presented. Each contrasting aspect of a ‘learning duality’ turns out to emphasise either assessment or reflection, which reinforces the idea that both are needed to facilitate sufficient learning for successful adaptive management. We hope this analysis can act as a springboard for further study, practice and reflection on these important and often underrated components of adaptive management. Conservation implications: The better understanding of assessment and reflection as being largely separate but complementary actions will assist adaptive management practitioners to give explicit attention to both, and to relate them better to each other.

Two approaches to the analysis of tags

Abstract: In recent literature on transformational grammar there has been a good deal of discussion of tag sentences (Klima, 1964; Katz and Postal, 1964; Bolinger, 1967; Arbini, 1969). The type of construction under consideration is exemplified in the following (incomplete) paradigm: (1) John has gone, hasn't he? (2) John hasn't gone, has he? (3) John has gone, has he (?) (4) John hasn't gone, hasn't he (?) (5) Come early, won't you (?) (6) Come early, will you (?)

The Absorption, Fluorescence and Phosphorescence and Phosphorescence of Single Crystals of 1,2,4,5-Tetrachlorobenzene and 1,4-Dichlorobenzene at Low Temperatures

Abstract: The emission spectra of ultra pure single crystals of 1, 2, 4, 5. tetrachlorobenzene (TCB) and 1, 4-dichlorobenzene (DCB) at temperatures from 4.2°K upwards are reported. In addition, by use of the phosphorescence excitation technique the singlet-triplet absorption spectrum at 4.2°K has been obtained. The phosphorescence emission of TCB at 4.2°K occurs predominantly from a defect origin “X” situated 48 cm−1 below the triplet exciton band. The triplet exciton energy level is at 26676 cm−1 from both emission and absorption studies. This is the triplet emission origin when the crystal is above 12°K. The temperature dependence of the emission intensity from the defect has an activation energy of 40±8 cm−1. This value is consistent with our suggestion of thermal depopulation of the traps. Single crystals of DCB show strong excimer emission and weak triplet exciton emission. There is no evidence for trapping levels. The triplet exciton emission. There is no evidence for trapping levels. The triplet exc...

A study in clinical cancer immunotherapy

Abstract: Twenty patients with advanced cancer have been treated by a vigorous course of immunotherapy, with the dual aim of clinical improvement and obtaining evidence of enhancement of immune response to the tumor Although the clinical response has not been striking, it has proved to be a safe procedure, and evidence has been obtained that cellular immune response can be enhanced by this procedure Usefulness of dermal hypersensitivity reactions in monitoring cancer immunity has been confirmed and correlation has been found between this enhanced immune response and apparent clinical improvement It is believed that the results of this investigation add further justification for carefully controlled trials of immunization earlier in the disease However, some results suggest that antigenic modulation of cancer cells has occurred in the face of immune attack If substantiated, this may be a further factor militating against successful immunotherapy of cancer

The use of oxygen isotope geothermometry on the granulites and related intrusives, Musgrave Ranges, central Australia

Abstract: Oxygen isotope equilibration involving quartz, feldspar and magnetite has taken place within the granulites of the metamorphic aureole of the intrusive charnockitic Ernabella Adamellite, and a temperature of approximately 550° C is indicated by 18O/16O values from quartz-magnetite and plagioclase-magnetite pairs. Pyroxene-magnetite fractionations are larger than equilibrium fractionations at this temperature, and demonstrate that caution is necessary in assigning estimates of temperature to highly metamorphosed rocks. The intrusive adamellite and related fine-grained and pegmatitic phases appear to have attained oxygen isotope equilibrium with the granulites at a similar temperature (approx. 550° C) which is here regarded as a late metamorphic equilibration temperature rather than the maximum temperature (estimated to be about 780° C) reached within the aureole. Oxygen was extracted from the minerals by means of bromine pentafluoride, and the isotopes were successfully measured without the normal prior conversion of oxygen to carbon dioxide.