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Showing papers by "University of Melbourne published in 1968"


Journal ArticleDOI
TL;DR: In this article, the authors propose a method to solve the problem of "missing links" in the context of artificial intelligence.VI. VII. VIII. IX. X. X
Abstract: VI. VII. VIII. IX. X.

465 citations



Journal ArticleDOI
TL;DR: The whole process of the eruptive stage of measles and subsequent immunity is mediated by the thymus-dependent system.

246 citations


Journal ArticleDOI
TL;DR: In this article, an average decline of 3.0 units of digestibility per unit of silica in the dry matter has been found, where W is cell walls, SiO 2 is silica on a dry matter basis, and L is the lignin content of acid-detergent fiber.

215 citations


Journal ArticleDOI
23 Mar 1968-Nature
TL;DR: Renin-LIKE enzymes have been extracted from a variety of tissues other than the kidney, including cat placenta1, rabbit uterine muscle and Placenta2–4, hog aorta5 and mouse submaxillary gland.
Abstract: RENIN-LIKE enzymes have been extracted from a variety of tissues other than the kidney, including cat placenta1, rabbit uterine muscle and placenta2–4, hog aorta5 and mouse submaxillary gland6,7.

161 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured the distributions of pressure on a bluff flat plate (fence) correlated with the characteristics of the smooth-wall boundary layer in which it is immersed, and found that the relative extent of upstream influence of the bluff-plate on the boundary layer was found to increase rapidly as h/δ decreases.
Abstract: Measurements of the distributions of pressure on a bluff flat plate (fence) have been correlated with the characteristics of the smooth-wall boundary layer in which it is immersed. For zero pressure-gradient flows, correlations are obtained for the variation of form drag with plate height h which are analogous in form to the ‘law of the wall’ and the ‘velocity-defect law’ for the boundary-layer velocity profile. The data for adverse pressure-gradient flows is suggestive of a ‘law of the wake’ type correlation. Pressures on the upstream face of the bluff-plate are determined by a wall-similarity law, even for h/δ > 1, and are independent of the pressure-gradient history of the flow; the separation induced upstream is apparently of the Stratford-Townsend type. The effects of the history of the boundary layer are manifested only in the flow in the rear separation bubble, and then only for h/δ > ½. The base pressure is also sensitive to free-stream pressure gradients downstream of the bluff-plate. The relative extent of upstream influence of the bluff-plate on the boundary layer is found to increase rapidly as h/δ decreases. One set of measurements of the mean flow field is also presented.

160 citations


Journal ArticleDOI
09 Mar 1968-Nature
TL;DR: Native Australian and introduced species of animals are adapted to severe sodium deficiency, and it has been shown that mechanisms controlling sodium homeostasis in wild rabbits are subject to profound stress.
Abstract: Native Australian and introduced species of animals are adapted to severe sodium deficiency. Effects of such a deficiency are aggravated by pregnancy and lactation, and it has been shown that mechanisms controlling sodium homeostasis in wild rabbits are subject to profound stress.

154 citations


Journal ArticleDOI
TL;DR: Smooth muscle cells of the external longitudinal coat of the guinea pig vas deferens were followed for 480 µ at 4.5-µ intervals, facilitating intermuscular and neuromuscular contacts and finding very little evidence of sensory innervation.
Abstract: Smooth muscle cells of the external longitudinal coat of the guinea pig vas deferens were followed for 480 µ at 4.5-µ intervals. Muscle bundles and fibers interwove, facilitating intermuscular and neuromuscular contacts. The ribbon- or rodlike muscle cells were about 450 µ long, 3,000 µ3 in volume, and 4,500 µ2 in area. The thickened nuclear zone lay anywhere along the middle one-third of the cell. Intercellular distances were 500–800 A. Intrusions were rare, and tight-junctions absent. At any level in a field of 80 muscle fibers there were 10–15 nerve bundles, each containing several varicose axons. Bundles and axons divided. Axons, en passage, were frequently within 500–1,000 A of a muscle fiber. En passage close contacts were rate. Axon terminations were bare, and bare axons invariably terminated. Bare terminations had scattered vesicle-laden varicosities and were from 10µ-60 µ in length, and all ended within 500 A of muscle fibers. Some made close contact with muscle fibers. Less than half of the muscle cells received this close contact, but some cells were approached by more than one termination. Most terminations involved more than one cell. Some cells had little or no innervation. Some groups of cells had a rich innervation. There was very little evidence of sensory innervation. These conclusions are not valid for other smooth muscles.

146 citations


Journal ArticleDOI
04 May 1968-Nature
TL;DR: This article is a slightly up-dated version of the presidential address to the Australian Society of Immunologists given by Sir Macfarlane Burnet in December 1967, which suggests that the mammalian immune system could have evolved from the haemocyte or primitive mobile cell of the invertebrate.
Abstract: This article is a slightly up-dated version of the presidential address to the Australian Society of Immunologists given by Sir Macfarlane Burnet in December 1967. He suggests that the mammalian immune system could have evolved from the haemocyte or primitive mobile cell of the invertebrate.

122 citations


Journal ArticleDOI
TL;DR: It is concluded that the uterine arterial supply of the guinea pig is innervated by both adrenergic constrictor and cholinergic dilator fibers, which appear to be functional only during pregnancy.
Abstract: The innervation of the extrinsic uterine arterial supply of the guinea pig has been studied using an isolated perfused preparation. The preparation was normally at minimal tone and responded to periarterial stimulation by a vaso-constriction which was mimicked by norepinephrine and abolished by bretylium. Constrictor responses both to stimulation and to norepinephrine were similar in both pregnant and non-pregnant states. In pregnant preparations, raising the tone of the vessels with norepinephrine revealed a powerful dilator response to periarterial stimulation. This response was mimicked by acetylcholine, potentiated by anticholinesterases, reduced by hyoscine, and abolished by-local anesthetic treatment. In contrast, virgin preparations showed only a weak dilator response to stimulation, while the response to acetylcholine even at high concentrations was usually negligible. Histochemical examination of the vessels revealed a dense plexus of fine nerve fibers exhibiting high acetylcholinesterase activity along the main uterine artery. The fibers lay in close apposition to the vascular muscle layer. Nerve fibers exhibited fluorescence for catecholamines were also abundant, but were distributed along the secondary as well as the main arteries. It is concluded that the uterine arterial supply of the guinea pig is innervated by both adrenergic constrictor and cholinergic dilator fibers. The dilator fibers appear to be functional only during pregnancy. The possibility of a noncholinergic dilator innervation is also discussed.

111 citations


Journal ArticleDOI
01 Aug 1968-Nature
TL;DR: Assimilation of carbon dioxide in the dark and on inverted stomatal rhythm are important adaptations of xerophytes as mentioned in this paper. But their adaptation is not suitable for the environment in which they live.
Abstract: Assimilation of carbon dioxide in the dark and on inverted stomatal rhythm are important adaptations of xerophytes.

Journal ArticleDOI
TL;DR: Littlejohn (1965) investigated geographic variation in male mating call structure in two closely related southeastern Australian tree frogs: Hyla ewingi and H. verreauxi, finding that whereas the calls of allopatric populations of the two species were remarkably similar, those of sympathetic populations were quite distinctive, differing especially in pulse repetition rate.
Abstract: Littlejohn (1965) investigated geographic variation in male mating call structure in two closely related southeastern Australian tree frogs: Hyla ewingi and H. verreauxi. The geographic ranges of these species are such that there is an extensive, linear zone of sympatry with adjacent areas of allopatry (see map in Littlejohn, 1965). It was found that whereas the calls of allopatric populations of the two species were remarkably similar, those of sympatric populations were quite distinctive, differing especially in pulse repetition rate (no overlap in ranges of variation). Other differences were also noted, their nature depending on the locations of the samples in the elongated zone of sympatry; i.e., whether they were from "deep" or "shallow" sympatry. Thus deep sympatric H. verreauxi differed further from shallow sympatric H. ewingi in having a lower carrier (dominant) frequency and reduced amplitude modulation; while deep sympatric H. ewingi differed further from shallow sympatric H. verreauxi in having a shorter note duration. In both species the shallow sympatric populations differed from the adjacent allopatric populations to a lesser extent. This pattern of geographic variation, particularly in pulse repetition rate, was interpreted as resulting from reinforcing selection for efficient premating reproductive isolation. Female response characteristics were presumed to follow the trends in male mating call divergence. Two predictions were made concerning potential premating isolation between allopatric populations. Firstly, since calls of remote allopatric populations of H. ewingi and H. verreauxi were so similar, it was suggested that this ethological character would not be effective as an isolating mechanism. Secondly, since the range of variation of pulse repetition rate in deep sympatric H. verreauxi did not overlap that of allopatric H. verreauxi (a difference comparable with that seen in the heterospecific sympatric populations), premating reproductive isolation of these populations was predicted. Although differences in mating calls have been shown to operate as important premating isolating mechanisms in other species of hylid frogs (Blair and Littlejohn, 1960; Littlejohn, 1960, 1961; Littlejohn, Fouquette, and Johnson, 1960; Littlejohn and Michaud, 1959; Michaud, 1962; Snyder and Jameson, 1965), direct experimental evidence was lacking in the H. ewingi complex. Accordingly, a program of call discrimination trials was arranged in order to test the assumption that the mating call differences were operating as premating isolating mechanisms. Since the calls of shallow sympatric H. ewingi are similar to those of adjacent allopatric H. ewingi, the predictions about the degree of premating isolation present between the two allopatric populations could also be tested. For practical reasons it was possible to test female H. ewingi and H. verreauxi from only one area-western sympatry. Even so, the results of the trials are convincing, allowing some conclusions and further predictions to be made.

Journal ArticleDOI
TL;DR: In this paper, the Galton-Watson branching process with two types of mating functions is considered, and sufficient and necessary conditions for the process to become extinct are found for all sufficiently large j.
Abstract: Consider a two-type Galton-Watson branching process with X nfemales and Y nmales in the nth generation, modified so that the (X inn}+1, Y n}+1) offspring in the (n + l)th generation are derived from Z n=ζ(X n, Tn) mating units which reproduce independently with the same offspring distribution for every mating unit in every generation. Necessary and sufficient conditions are found for the process to become extinct (i. e., Z N= 0 for some positive integer N) with probability one for the two particular mating functions ζ(x, y) = x min(1, y), which corresponds to perfect promiscuity, and ζ(x, y) = min(x, dy) (d a positive integer), which corresponds to polygamous mating with d wives per husband when there is an abundance of females. Essentially, the condition for pr(Z n→ 0)=1 to be true is the commonsense condition that E(Z 1¦Z0=j) ≦ j for all sufficiently large j.

Journal ArticleDOI
TL;DR: In this article, the authors propose models constructed from functions homogeneous of degree one which overcome these difficulties, yet leave a wide choice of models, leaving a wide range of models for a mixture system.
Abstract: SUMMARY Care needs to be exercised in the choice of model for a mixture system. The polynomial model, for example, cannot satisfactorily account for components which are inert or have additive effects and its coefficients lose their interpretative value when the variables are the proportions of components in the mixture. This paper proposes models constructed from functions homogeneous of degree one which overcome these difficulties, yet leave a wide choice of models.

Journal ArticleDOI
TL;DR: It appears that humoral cytotoxic antibodies are associated with kidney transplant rejections and that they either act directly on the transplant or serve as indicators of a state of presensitization.
Abstract: SUMMARY A total of 231 serum samples from 41 patients before and after first and second kidney transplants were investigated for the presence of cytotoxic antibodies. After transplantation 11 of 29 patients had cytotoxic antibodies in contrast to 4 of 21 patients before transplantation. In 10 patients who had their renal grafts removed because of rejection, 9 had demonstrable cytotoxic antibodies. Patients with cytotoxins generally tended to have worse kidney function and transplant failure than patients without cytotoxins (P

Journal ArticleDOI
TL;DR: A chart of intrauterine weight, based on data from 2637 patients, is presented together with details of the hospital population and the methods used in selecting the patients.
Abstract: SYNOPSIS The neonate whose birth-weight diverges widely from the average for the period of gestation is subject to special hazards. Acceptable local standards of weight are required to identify these infants at risk. A chart of intrauterine weight, based on data from 2637 patients, is presented together with details of the hospital population and the methods used in selecting the patients. The influence of certain complications during pregnancy is briefly discussed.

Journal ArticleDOI
TL;DR: A case of Fretal Vaccinia and Vocational End Results Following Rehabilitation of Upper-Extremity Amputees, and an Improved Tear-Conserving Goggle Attachment.
Abstract: REPORTS OF CASESA Case of Fretal Vaccinia, by G. H. Altkens, R. Bowman, D. Hansman, R. R. Hollis and A. M. Murphy 173 Minimal-Pressure Oxygen Recompression Treatment of Decompression Sickness, by Ronald Prehn Palmer .. .. .. .. .. 174 ORIGINAL ARTICLESPage Heparin In the Treatment of Venous ThromboEmbolic Disease: Administration, Control and Results, by E. F. O'Sullivan, J. Hirsh, R. A. McCarthy and G. C. de Gruchy .. .. .. .. 153 Treatment of Chronic Hepatic Encephalopathy with Lactulose, by W. P. Fung and O. T. Khoo 160 The Intravenous Tolbutamide Response In the Diagnosis of Diabetes, by R. L. Walker .. .. 164 Vocational End Results Following Rehabilitation of Upper-Extremity Amputees, by W. Graeme Shepherd and Donald Cain .. . . . . .. .. 166 An Improved Tear-Conserving Goggle Attachment, by the Reverend Frank Flynn, In association with A. Schulmelster . . . . .. .. .. 170 A Survey of Antibiotic Sensitivity Testing, by Scientific Projects Committee (Microbiology), The College of Pathologists of Australia .. 171

Journal ArticleDOI
TL;DR: The neuromuscular inter‐relationship was investigated in three regions of the trout heart: the sinoauricular junction, the auricle and the ventricle; it is suggested that every muscle cell in this region of the fish heart has at least one and probably many more individual neurOMuscular contacts.
Abstract: The neuromuscular inter-relationship was investigated in three regions of the trout heart: the sinoauricular junction, the auricle and the ventricle. The innervation of the sinoauricular tissue was unusually dense; in one plane of section, the number of axons less than 200A apart from cardiac muscle cells was approximately equal to the total number of muscle cells. Some muscle cells had up to eight close axon contacts. It is suggested that every muscle cell in this region of the fish heart has at least one and probably many more individual neuromuscular contacts. Many ganglion cells, some with presynaptic terminal were observed in the sinoauricular region. Multivesicular bodies were commonly seen in the cytoplasm. The innervation of the ventricle near the apex was very sparse and that of the auricle appeared to be intermediate between the two extremes. The ventricular muscle cells were somewhat larger and contained a higher area of myofibrils than those in the auricle and the sinoauricular tissue. M-lines in the myofibrils were demonstrated in the cardiac muscle of the trout. Intraaxonal vesicles were mostly agranular. However, in about 9.5% of the 1472 axon profiles examined, a number of small (500–700A) and large (∼800A) granular vesicles were also present, which suggests that, in contrast to the general view, there are some nerves containing catecholamines supplying the fish heart. It is likely that the sinoauricular region in the fish heart is homologous to the smus node in avian and mammalian hearts.

Journal ArticleDOI
TL;DR: The etiology of this fatty liver appears to differ from the cases in which there is a decreased secretion of the plasma lipoproteins, and a change in the composition of the very low density lipoprotein in the rats deficient in essential fatty acids is found.

Journal ArticleDOI
TL;DR: Under none of the conditions tested in any of the 3 tissues was the conversion of 20α-hydroxycholesterol-7α-3H to the steroid hormones increased in the presence of the trophic hormones.
Abstract: Slices of bovine adrenal cortex, bovine corpora lutea and rabbit testes were incubated with 20α-hydroxycholesterol-7α-3H or with cholesterol-7α-3H with and without the trophic hormones ACTH (adrenal cortex) or ICSH (corpora lutea or testes) added in vitro. In confirmation of previous findings, the trophic hormones increased the conversion of cholesterol-3H to cortisol-3H (adrenal cortex), progesterone-3H (corpora lutea) and testosterone-3H (testes). On the other hand, the trophic hormones produced a slight decrease in the conversion of 20α-hydroxycholesterol-3H to the same steroid hormones. In the case of the corpus luteum this decrease was less when incubation was continued for longer times, but under none of the conditions tested in any of the 3 tissues was the conversion of 20α-hydroxycholesterol-7α-3H to the steroid hormones increased in the presence of the trophic hormones. In the case of the testis similar results were observed 1 hr after a single intravenous injection of ICSH. These findings were m...

Journal ArticleDOI
TL;DR: It was concluded that the presence of noradrenergic terminals about ganglion cells in the enteric plexuses of mammals is a relatively recent evolutionary development.

Book ChapterDOI
TL;DR: There is far greater agreement within and between countries about the safest and most efficacious vaccines to be used in human vaccination than there is with vaccines destined for use in animals.
Abstract: The methods of reducing the impact of viral infections on animals of economic importance include a range of management practices such as test and slaughter, hygiene and sanitation, and immunization. The most generally applicable way of preventing viral diseases is by immunization, and the control of a large number of diseases of animals by immunization is the outstanding achievement of veterinary medicine in this century. The field has been catapulted to a new plane of promise by the application of new technologies including the use of recombinant DNA, site-directed mutagenesis, synthetic peptides, and bacterial, yeast, and mammalian expression systems. There are important differences between immunization practices in humans and animals. Except in developing countries, an economic constraint is of little importance in human medicine but is very important in most areas of veterinary practice. There is far greater agreement within and between countries about the safest and most efficacious vaccines to be used in human vaccination than there is with vaccines destined for use in animals. Viral vaccines have traditionally been classified into two broad categories: live-virus and inactivated. Most live-virus vaccines are attenuated mutants selected for their relative avirulence.

Journal ArticleDOI
TL;DR: The effect of crustecdysone on protein synthesis in body wall from treated 7 to 8 day larvae is proportional to the logarithm of the dose over the range 0·002 to 0·2 μg/larva, and the response of proteinhesis in fat body to increasing dose in this range is slight.

Journal ArticleDOI
TL;DR: This work is not able to show evidence of sensitization of recipients of renal allografts by whole-blood transfusions, thus providing the paradox alluded to in the title.
Abstract: PATIENTS in terminal renal failure who are awaiting renal transplantation are generally maintained on frequent bremodialysis. This period of maintenance may last for several months, during which time the patient may receive a number of whole blood transfusions, depending on the type of machine used for dialysis. This ranges from no transfusions to as many as 100 transfusions in the months immediately before transplantation. As it is known that leukocytes carry transplantation antigens (Medawar, 1946; Friedman et alii, 1961; Rapaport et alii, 1964), it might be expected that these frequent transfusions of whole blood (with leukocytes) would lead commonly to sensitization of potential recipients against a subsequent renal allograft. In fact, because of this theoretical risk of sensitization, many transplantation units use only leukocyte-free blood for transfusions. If this risk is real, it should be possible to demonstrate that renal allografts have a stormier early course, as judged by rejection crises, when the recipient has received a large number of transfusions before grafting. As just the opposite is suggested to be the case by two other units (Dossetor et alii, 1967; Michielsen, 1966), we have examined our own experience in this regard. We, too, are not able to show evidence of sensitization of recipients of renal allografts by whole-blood transfusions, thus providing the paradox alluded to in the title. The implications of the results to be described will be discussed at some length.

Journal ArticleDOI
TL;DR: It is concluded that intimal foam cells are primarily responsible for the lipid synthesis that occurs in the atherosclerotic lesion.
Abstract: The uptake of 14C-labeled oleic acid and its incorporation into combined lipids by aortic intimas from normal and cholesterol-fed rabbits has been investigated in vitro. More than five times as much oleic acid was taken up by the atherosclerotic intima as by the normal intima. About twice as much oleic acid was incorporated into phospholipid, and twenty times as much into cholesterol ester by the atherosclerotic intima as by the normal. Lecithin was the major phospholipid synthesized from oleic acid in both normal and atherosclerotic intimas. Radioautographs of the atherosclerotic vessels show that the 14C-labeled oleic acid and its metabolic derivatives, principally phospholipid and cholesterol ester, were localized in sudanophilic cells in the intima in both early and advanced lesions. It is concluded that intimal foam cells are primarily responsible for the lipid synthesis that occurs in the atherosclerotic lesion.

Journal ArticleDOI
TL;DR: St 155 differs from other clinically useful antihypertensives in its mode of action, and it is suggested that the depressor action of St 155 may be due to a central reduction of sympathetic outflow to the heart and blood vessels.

Journal ArticleDOI
TL;DR: FSH appears to increase protein biosynthesis whether spermatids are present or not, in keeping with earlier histological reports indic...
Abstract: Stimulation of protein biosynthesis in rat testis by glucose was studied in rats of various ages and in hypophysectomized animals. Glucose did not increase protein synthesis in the testis before the age of 28 days and the stimulation observed in the adult gradually declined following hypophysectomy until no response was observed 25 days after operation. It has been reported that spermatids appear at 28 days of age and disappear from the adult testis within 25 days after hypophysectomy. Our findings support previous suggestions that glucose stimulates protein biosynthesis in spermatids. A single injection of FSH stimulates protein biosynthesis in testes of rats aged 15–24 days but not in testes of rats more than 24 days of age. The adult testis responds to FSH within 18 hr of hypophysectomy and continues to respond to a single injection for at least 25 days after operation. FSH appears to increase protein biosynthesis whether spermatids are present or not, in keeping with earlier histological reports indic...

Journal ArticleDOI
TL;DR: There is a group of people centred around zoology and anatomy departments in Oxford, but involving London as well, who are pressing for the serious study of human biology in universities as a necessary preliminary to sociology and eventually as the only effective method of bridging the gap between Snow's "two cultures".
Abstract: oldest of British universities. There is a group of people centred around zoology and anatomy departments in Oxford, but involving London as well, who are pressing for the serious study of human biology in universities as a necessary preliminary to sociology and eventually as the only effective method of bridging the gap between Snow's \"two cultures\". The people primarily concerned are Pringle, Harrison, Weiner, Barnicot and Tanner-all sound academics with their feet on the ground. At present they are not specially interested in medicine. In one sense the whole of one's training in medicine is a training in human biology, but it differs rather sharply from what is now regarded as the realm of \"human biology\" by the group in Oxford. Medicine has necessarily been concerned with anatomy, physiology, biochemistry and their morbid counterparts. All are essentially common to other mammals as well as man. As long as we were essentially concerned only with the impact of the, environment in disease, or with the restoration of physical function by manipulation or surgery, we were not dealing with really human problems. It is characteristic of the present or the immediate past that we have always and rightly gone to the laboratory mammals-mouse, rat, guinea-pig and rabbit -to seek our answers. Human biology in its new sense has as yet had hardly any impact on medicine. It is concerned with those things which are essentially human but which can be looked at in the same general way that biologists can look at what is unique in the situation of any other mammalian species. The human biologist is concerned with the evolutionary history of man, with the physical and functional variations we find within the species and with the way in which these are transmitted by inheritance. He is concerned with the processes of growth, maturation, aging and death, with human numbers, their distribution and change in time: human ecology, that is. Finally and most importantly, he is looking for a new scientifically valid approach to human behaviour to psychology, if you like. There is a rapidly rising Interest in the view that this approach is coming from the science of animal behaviour now called ethology. At the present time there is a spate of interest In the behaviour of the higher primates (chimpanzee and gorilla) in their natural state. However, as in so many other fields, there are great differences of opinion as to how primate behaviour can be related to the behaviour of man's early ancestors. What is apparently accepted by everyone in the field is that human as well as animal behaviour is based on Inheritable conditions which provide the necessary background on which environmental and particularly cultural circumstances can give rise to specific behaviour.

Journal ArticleDOI
TL;DR: The findings demonstrate that chronic renovascular hypertension is not necessarily associated with abnormal concentration of renin or aldosterone in peripheral blood, and suggest that the renin-angiotensin system is not the cause of the continuing hypertension.
Abstract: Sheep were made chronically hypertensive by constriction of one renal artery. Blood levels of renin, aldosterone and cortisol were measured. Sodium balance was estimated from measured food intake and renal and fecal sodium loss. Animals with a clipped single kidney and animals with mild hypertension after unilateral clipping showed only a temporary increase of renin, aldosterone and cortisol in peripheral blood. Animals with severe hypertension after unilateral clipping became sodium depleted, due to increased renal excretion of sodium. Renin and aldosterone blood levels did not return to normal levels but increased progressively with the sodium deficit. The findings demonstrate that chronic renovascular hypertension is not necessarily associated with abnormal concentration of renin or aldosterone in peripheral blood, and suggest that the renin-angiotensin system is not the cause of the continuing hypertension. Severe hypertension may cause sodium depletion in animals with both kidneys in situ. The effect...

Journal ArticleDOI
TL;DR: In the presence of interfering ions, such as sulfate and phosphate, the effect can be used to determine fluoride ion in this concentration range as mentioned in this paper, which can be demonstrated in the analysis of a wide range of inorganic fluorides.
Abstract: Fluoride ion depresses the absorption of magnesium in the air-coal gas flame, the change in absorbance of the magnesium resonance line at 2852 A being proportional to the fluoride concentration over the range 0.2-20 ..mu..g/ml (10/sup -5/-10/sup -3/M). In the absence of interfering ions, principally sulfate and phosphate, the effect can be used to determine fluoride ion in this concentration range. An alternative, though somewhat less sensitive, technique is based on the enhancement of zirconium absorption by fluoride ion in the nitrous oxide-acetylene flame; this allows the determination, with a high degree of freedom from interference, of fluoride ion over the range 5-200 ..mu..g/ml (2.5 x 10/sup -5/-10/sup -2/M). In the presence of phosphate, which interferes with the zirconium method, a similar enhancement of titanium absorption can be used for fluoride determinations in the range 40-400 ..mu..g/ml (2 x 10/sup -3/-2 x 10/sup -2/M). These atomic absorption methods for fluoride determinations have been found to be considerably more rapid than more classical methods and in many cases can be used directly without prior separation of fluoride. Their application has been demonstrated in the analysis of a wide range of inorganic fluorides. 14 references, 3 figures, 3 tables.