Showing papers by "University of Western Australia published in 1973"
01 Feb 1973
TL;DR: The points of zero charge (pzc) of synthetic hydroxyapatite and fluoraphatite were measured by a titration technique in this article and the titrations were reversible if the pH value did not go below 7.5.
Abstract: The points of zero charge (pzc) of synthetic hydroxyapatite and fluorapatite were measured by a titration technique. The titrations were reversible if the pH value did not go below 7.5 for hydroxyapatite and 5.5 for fluorapatite. The pzc value obtained for hydroxyapatite in KCl, which was shown to be indifferent, was 8.5 and unaffected by the surface area of the sample and the use of KNO 3 , KC1O 4 and (CH 3 ) 4 NCl in place of KCl. Aging of the suspension from 16 to 504 hr did not affect the pzc although there was some increase in charge on either side of the pzc at a given pH value with increasing equilibration time. There was a shift in pzc to 7.6 when NaCl was used as supporting electrolyte indicating substitution of Na + for Ca 2+ on the surface. The presence of 5 × 10 −4 M F − moved the pzc to 6.8, a value close to that obtained for fluorapatite.
176 citations
TL;DR: The specificity of the estrogen receptor of the human uterus was investigated with the use of a large number of compounds mostly steroids, with 3 notable characteristics in the steroids of highest affinity to the receptor.
124 citations
TL;DR: The metabolic properties of synaptosomes prepared from the crude mitochondrial and crude nuclear fractions of the medulla/spinal cord showed similar properties, glycine being enriched in the latter, while electrically stimulated release of glycine and other amino acids was reduced.
Abstract: The metabolic properties of synaptosomes prepared from the crude mitochondrial and crude nuclear fractions of the medulla/spinal cord were studied. They showed similar properties, glycine being enriched in the latter. The respiration and glycolysis rates were similar to the cortical synaptosomes previously studied. A major difference from cortical synaptosomes was the enrichment of glycine. Medulla/spinal cord synaptosome suspensions and beds responded metabolically to electrical pulses; respiration and lactate production increased by 50 and 25 per cent respectively. Differential release of glutamate, aspartate, GABA and glycine occurred during both electrical stimulation, and when potassium in the medium was increased. Omitting calcium and adding EGTA greatly reduced this response with both forms of stimulation. The electrically induced release of GABA was completely reversible whilst that of aspartate and glycine was only partially reversible. The electrically stimulated release of glycine and other amino acids was reduced in synaptosomes prepared from rats treated intramuscularly with tetanus toxin 15 hr before death. No action of the toxin was seen on synaptosomes incubated with tetanus toxin after preparation.
110 citations
TL;DR: The problem known as ‘second-year clover mortality’ is primarily due to low numbers of clover rhizobia in the soil at the end of the growing season, which is aggravated over the long hot dry summer, when there is a further decline in numbers.
Abstract: The survival over summer of field-grown root nodule bacteria was studied in the field and the laboratory during the course of an investigation into a nodulation problem of annual clovers. Dry field soils containing Rhizobium trifolii and R. lupini were subjected to a range of temperatures in the laboratory, the bacteria surviving 6 h exposure to temperatures as high as 80°C. Soil temperatures during summer were recorded at different depths. Populations of rhizobia were estimated at these depths from the end of the growing season (October) to early autumn (April) in plots which had carried dense swards of subterranean clover and Serradella. High populations of R. lupini were maintained in the Serradella plots throughout the summer. Populations of R. trifolii in the subterranean clover plots were initially much lower, and declined with both time and depth. The problem known as ‘second-year clover mortality’ is primarily due to low numbers of clover rhizobia in the soil at the end of the growing season. This situation is aggravated over the long hot dry summer, when there is a further decline in numbers.
102 citations
TL;DR: In this article, the standard metabolic rate of western plumed pigeons (Lophophaps ferruginea ) averages 0·88 ml O 2 (g hr) −1 during summer and late fall, respectively.
101 citations
TL;DR: In this article, a model of ion adsorption on variable charged surfaces is presented and discussed, and a comparison with experiment suggests that the model explains most principal features of the model.
Abstract: A model of ion adsorption on variable charged surfaces is presented and discussed. Comparison with experiment suggests that the model explains most principal features.
96 citations
95 citations
TL;DR: The results indicate that information about the physical features of verbal stimuli is retained in a visual code that is partially’ or wholly independent of the verbal code for the same stimuli.
Abstract: lorty Ss were given a continuous recognition memory test in which each word was presented twice, eilher in the same print or in different print on the two occasions. The results showed that (a) recognition performance was facilitated to a small but statistically significant extent in the same-print condition and that (b) Ss could reliably re port first presentation print for recognized items for at least 1'/2 min. In a second experiment, the stirnuli used were nonsense strings 01' from five to seven letters instead 01' words. This rnanipulation increased the same-print advantage in recognition but reduced 55' ability to report first print form. The results indicate that information about the physical features 01' verbal stimuli is retained in a visual code that is partially or wholly independent of the verbal code for the same stimuli. The results are inconsistent with the conc1usion that the visual code is stored only as adependent attribute 01' the verbal code in mernory. When a person reads a word, one possible assumption is that the item is immediately translated into an auditory-verbal or semantic code. According to this view, the verbal and semantic properties of the word are extracted, whereas normally redundant information about the physical properties of the visual stimulus are lost. However, the results of recent studies (e.g., Kroll, Parks, Parkinson, Beiber, & Johnson, 1970: Warrington & Shallice, 1969) show that information about the physical properties of visually presented verbal stimuli may be retained in memory for 10-25 sec, aperiod of time substantially beyond that whieh eould he useful for word identification. The present study was implemented with a view to (a) providing further knowledge about the duration of visual persistence for verbal stimuli and (b) gaining some insight into the eoding processes involved in the retention of the representational as distinet from the semantic attributes of verbal stimuli. The present study used a modification of the continuous trial recognition mernory paradigm introduced by Shepard and Teghtsoonian (1961), In their experiment, Ss were exposed to a series of words, within which each item was repeated onee, at one of several possible retention intervals. The technique was modified here so that an item could be repeated in the same physical form (e.g., CARROT/CARROT) or in a different physical form (e.g., CARROT/carrot) on the first and second presentations in the continuous series. Two questions were considered in the present experiment. The first question involved a direct
84 citations
TL;DR: Dose response curves revealed certain age-dose level interactions which were consistent with the hypothesis that cholinergic inhibitory mechanisms in the brain develop gradually in the rat.
Abstract: Four studies are reported examining the development of spontaneous alternation behavior in rats. Spontaneous alternation was found to increase from a rate of around 20% in 15-16 day old rats to around 90% in 100-day olds. Increasing the length of confinement in the 1st chosen goal arm did not affect alternation rats. Spontaneous alternation could be disrupted or facilitated in mature animals by the administration of either scopolamine hydrobromide or physostigmine sulphate, drugs which had no effect on the typical alternation pattern of 16-day olds, but appeared to begin to have an effect at around 24 days. Dose response curves revealed certain age-dose level interactions which were consistent with the hypothesis that cholinergic inhibitory mechanisms in the brain develop gradually in the rat.
84 citations
TL;DR: Air pollution and cigarette smoking have been associated with an increased susceptibility to respiratory infection and chronic exposure to sulphur dioxide and carbon has been found to decrease the immune response of mice to inhaled antigen.
Abstract: THE bronchopulmonary system, one of the most important sites of access for antigen into the body, has a highly developed lymphatic system1 and the capacity to effect a local immune response2. Any modification of these defences by the environment is likely to have a lasting influence on the health of an animal. Chronic exposure to sulphur dioxide and carbon has been found to decrease the immune response of mice to inhaled antigen3. Cigarette smokers have also been found to have decreased serum antibody to influenza virus after infection or vaccination4. Both air pollution and cigarette smoking have been associated with an increased susceptibility to respiratory infection5,6.
82 citations
TL;DR: R.F. was more common than expected amongst people with raised blood-pressure, and also amongst women with dyspnœa, angina, or cerebrovascular symptoms, and that the vascular risk associated with smoking may be related in part to autoantibody induction.
TL;DR: In this article, a partial solution to the problem of characterizing the rings R for which Abelian groups can be characterized is presented, which is the same problem posed by Fuchs in his well-known book "Abelian Groups".
Abstract: One of the still unsolved problems posed by Fuchs in his well-known book “Abelian Groups” [2] is Problem 45: characterize the rings R for which . I present here a partial solution.
TL;DR: The 2,4-D anion was reversibly adsorbed on positively charged goethite surfaces, and maximum adsorption was observed near the pKa of 2, 4-D (2.73) and at low ionic strength as discussed by the authors.
Abstract: Summary
Adsorption, of the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) on an iron oxide, goethite, was studied in aqueous suspensions as a function of solution pH, ionic strength of the medium, and initial 2,4-D concentration.
The 2,4-D anion was reversibly adsorbed on positively charged goethite surfaces, maximum adsorption being observed near the pKa of 2,4-D (2.73) and at low ionic strength. Within certain levels of adsorption (5–22 mg 2,4-D adsorbed/g goethite) the complex became hydrophobic and floated to the liquid surface. This flotation effect disappeared on further adsorption.
It is suggested that adsorbed 2,4-D anions are orientated with their hydro-phobic aromatic ends directed towards the solution, the carboxyl groups being weakly bound to positive sites on the oxide surface. At high levels of adsorption, some of the anions are orientated in the opposite direction by π–π interaction, with the first adsorbed layer and the surface reverts to its hydrophilic nature.
TL;DR: In this article, a least-cost method for designing water distribution systems is presented, in which the cost of the system is to be minimized subject to equality and inequality constraints, and the inequality constraints are eliminated by a transformation of Box, from which Haarhoff and Buys' method for equality constraints is used to solve the remaining part of the problem.
Abstract: A least-cost method for designing water distribution systems is presented. Basically, the behavior of a network obeys two physical laws: (1) the conservation of headloss around any loop; and (2) the continuity of fluid flow at any pipe junction. From these physical laws and from the performance criteria that the pressures at the delivery points of the network must be above a specified level, a nonlinear programming problem is formulated, in which the cost of the system is to be minimized subject to equality and inequality constraints. Because of their simplicity, the inequality constraints are eliminated by a transformation of Box, from which Haarhoff and Buys' method for equality constraints is used to solve the remaining part of the problem. The method of solution is so coded that it is capable of handling existing or predetermined design components. Various sensitivity analyses are made on a model network, yielding results which can be useful to complex systems.
TL;DR: In this article, a method of lignin determination in HCl-activated triethylene glycol at 121 °C was proposed, which relates well to in vitro organic matter digestibility.
Abstract: A method of lignin determination which utilises the solubility of lignin in HCl-activated triethylene glycol at 121 °C is described. Experiments on a range of samples indicate that the method is simple, fast and reproducible, and relates well to in vitro organic matter digestibility.
TL;DR: Growing-season populations of rhizobia associated with annual host-plant roots and nearby soil were examined in a field soil showing a nodulation problem in the second year after establishment and Rhizobium lupini reached higher populations at a faster rate than R. trifolii.
Abstract: Growing-season populations of rhizobia associated with annual host-plant roots and nearby soil were examined in a field soil showing a nodulation problem in the second year after establishment. Rhizobium lupini reached higher populations at a faster rate than R. trifolii. A sharp drop in the population of R. trifolii associated with subterranean clover roots early in the growing season was followed by a recovery to high numbers. No such phenomenon occurred with R. lupini. The numbers of rhizobia under patches of non-nodulated plants in second-year stands were very low, usually <5/g soil, whereas the numbers under healthy plants in problem stands were similar to those under established stands. Differences in the colonization of both root and soil by R. trifolii in the first year were reflected in the second-year nodulation.
TL;DR: Stimulation during learning resulted in a strong persevarative response tendency and results were considered in terms of a registration-consolidation-retrieval continuum.
TL;DR: Evidence is presented which may indicate that in contrast to estriol, the anti-estrogens CN-55945, clomiphene, ICI-46474 and U-11100A influence the estradiol-17β-receptor interaction by allosteric (apparent) competition.
TL;DR: The surface characteristics of murine macrophages, epitheliod and giant cells have been studied under the scanning electron microscope and epithelioid cells showed a ‘cobblestone’ surface and many filiform processes.
TL;DR: This study is the first to consider in detail the structure, myology, nerve supply, and function of the tongue in the Pholidota, and compared with similar arrangements present in other mammals which feed on a diet requiring little or no mastication.
Abstract: The tongue, together with its associated structures, was studied in two species of African pangolins, Manis gigantea and M. tricuspis. Observa- tions were made on living animals, and anatomical studies were made on seven adults. The tongue, 70 centimeters long in Manis gigantea and 30 centimeters long in M. tricuspis, is of similar morphology in the two species. It lies ventral to the larynx and trachea and occupies the thorax and abdomen just internal to the body waIl. A description is given of the mandible, hyoid, and sternum; the attachments of transverse and longitudinal tongue protrudor and retractor muscles; the histology of the tongue epithelium and lytta; the intrinsic muscle arrangements and the salivary glands. The structural features are related to the specialized pangolin mode of food gathering, and compared with similar arrangements present in other mammals which feed on a diet requiring little or no mastication. African pangolins exhibit many interesting anatomical specializations. The forelimbs are pronograde and well adapted for tearing apart termite nests; the dorsal and lateral body hair is modified to form scale-like plaques; the tail is extremely muscular, contains a large complex retia mirabilia, and in the arboreal species possesses a terminal caudal sensory pad containing many Pacinian corpuscles. Such morphological adaptations and those of the tongue and jaws are specializations to a particular diet and mode of life, namely, anteating. Accounts of the tongue and associated structures in the Pholidota are con- fined to brief, and not wholly consistent reports. Cuvier (1845), Weber (1894), and Beddard (1909) described various aspects of pangolin anatomy, but only mentioned the tongue in passing. The anatomy of the taste organs of the tongue has been described in detail (Bronn, 1874; Tuckerman, 1890; Sonntag, 1923; Kubota et al., 1962). Our study is the first to consider in detail the structure, myology, nerve supply, and function of the tongue in the Pholidota.
TL;DR: In this article, the vapour pressure of degassed normal water between 273.15 and 298.15 K was measured, together with 37 values for D2O (purity: 99.75 mass per cent).
TL;DR: The parent magma for the sills appears to have been rich in MgO (15-18%) and is probably represented by the spatially associated high-Mg basalts found in the region of Western Australia.
Abstract: Small Archaean, pre-metamorphic layered sill-like intrusions showing “ Stillwatertype” differentiation are widespread in the Eastern Goldfields region of Western Australia. The sills have undergone low-grade metamorphism, but the retention of some original minerals and excellent preservation of primary textures have enabled most of their original features to be reconstructed. Despite their small size in comparison with well known layered intrusions, simple differentiation sequences are developed ranging upwards from dunite and harzburgite through orthopyroxenite, norite, norite-gabbro and gabbro to granophyre and anorthosite. The parent magma for the sills appears to have been rich in MgO (15–18%) and is probably represented by the spatially associated high-Mg basalts found in the region. The complexes are interpreted as being contemporaneous with volcanism and may be high-level emplacements.
TL;DR: In this paper, a descriptive classification of these units is proposed, based on the application of the concept of etch landsurfaces, the central theme of which incorporates both deep chemical weathering and differential stripping of the resultant saprolite.
Abstract: Landscapes in southwestern Australia are associated with variable proportions of a deep mantle of chemical weathering. By recognizing a continuum of landscapes showing a minimal amount of erosional modification of the deep mantle through to surfaces exhibiting intrusive stripping, broad soil-landscape units have been delineated. A descriptive classification of these units is proposed, based on the application of the concept of etch landsurfaces, the central theme of which incorporates both deep chemical weathering and differential stripping of the resultant saprolite.
TL;DR: Within 30 minutes after exposure to cigarette smoke, many murine peritoneal or alveolar macrophages die, while survivors exhibit an increase in tritiated RNA synthesis both in vivo and in vitro.
Abstract: Experiments have been carried out on the immediate effects of cigarette smoke on murine peritoneal and alveolar macrophages, fibroblasts, and epithelioid cells. Within 30 minutes after exposure to cigarette smoke, many murine peritoneal or alveolar macrophages die, while survivors exhibit an increase in tritiated RNA synthesis both in vivo and in vitro. The susceptibility of these cells to cigarette smoke contrasts sharply with that of murine fibroblasts and mixed cultures of fibroblastic and epithelioid cells derived from explants of fetal mouse lung.
TL;DR: The results indicate that maternal plasma transferrin is an adequate source of iron for the fetal guinea pig, and that placental transfer of iron is an active process, dependent on cellular metabolism, in which maternal plasmatransferrin is taken up by the placenta followed by removal of the iron from the transferrin and transfer to the fetal blood.
Abstract: The uptake of transferrin and iron by the placenta and iron transfer to the fetuses were studied in the guinea pig using radioiodine labelled guinea pig transferrin and albumin and 59Fe. The amount of labelled transferrin bound by the placenta increased during the first 30 min after injection, then reached steady levels which were maintained for the next 60 min. No labelled transferrin or albumin was detected in the fetal blood. The rate of transfer of iron from maternal plasma to the fetuses increased after the 25th day of pregnancy to reach a maximum at about the 54th day, and then decreased markedly by the 65th day.
The effects of hypoxia and of metabolic inhibitors on iron transfer were studied by in vivo perfusion of the placenta. Reduction in 59Fe transfer was observed in animals breathing 10 or 15% oxygen in nitrogen, or when sodium arsenite (5 mM), sodium cyanide (10 mM) or 2,4-dinitrophenol (10 mM) were added to the perfusate.
The results indicate that maternal plasma transferrin is an adequate source of iron for the fetal guinea pig, and that placental transfer of iron is an active process, dependent on cellular metabolism, in which maternal plasma transferrin is taken up by the placenta followed by removal of the iron from the transferrin and transfer to the fetal blood.
TL;DR: Variation in climate factors and fungal spore counts are associated with variation in the asthma attendance rate in the Perth area between April and September.
Abstract: Summary: The daily incidence of asthma as measured by the attendance of children with asthma in the season of low pollen numbers (April to September) is compared with total casualty attendance figures, the atmospheric pollen and fungal spore counts, and with climatic conditions including atmospheric ionization
A multiple regression computer programme with up to three days lag for the effect of climate factors on asthma attendance and fungal and pollen counts was used to demonstrate association between these factors Statistical analysis of this data shows that there is a significant association between reduction in asthma attendance (p < 005) and increased atmospheric ionization three days before, increased barometric pressure two days before, and increased temperature one day before This association accounts for 1618% of the daily variation in asthma attendance There is also a significant association between increased fungal spore counts and increased asthma (p < 005) In this April to September period there is no association between pollen grain counts and asthma Climate factors, as might be expected, are significantly associated with variation in pollen (2644%) and fungal spore numbers (2174%) With the exception of atmospheric ionization three days before (being associated with both a reduction in fungal spore count and a reduction in asthma attendance), there is no coincidence between the climate factors associated with variation in air spora numbers and those associated with variation in attendance with asthma It would appear that, in the Perth area between April and September, variation in climate factors and fungal spore counts are associated with variation in the asthma attendance rate
TL;DR: In this paper, the assignment of absolute stereochemistry to the acetoxyhydroxy-acid (1) from D. attenuata and the lactone (6) from the var. linearis is given.