Showing papers by "Linköping University published in 1983"
TL;DR: The interface zone between titanium implants and bone is considered at the macroscopic, microscopic, and molecular levels and includes a tightly adherent titanium oxide layer on the surface of the implant which may be similar to a ceramic material in relation to tissue response.
Abstract: The interface zone between titanium implants and bone is considered at the macroscopic, microscopic, and molecular levels. A high rate of successful dental implants of pure titanium is associated with a very close apposition of the bone to the titanium surface, called osseointegration. At the macroscopic level, osseointegration allows efficient stress transfer from the implant to the bone without abrasion or progressive movement that can take place if a fibrous layer intervenes. At the microscopic level, surface roughness and porosity provide interlocking of the implant and bone tissue which grows into direct contact with titanium. Sections studied in the electron microscope show that calcified tissue can be identified within 50 A of the implant surface. The interface zone includes a tightly adherent titanium oxide layer on the surface of the implant which may be similar to a ceramic material in relation to tissue response. The five year success rate of 90% in 2895 implants in clinical trials since 1965 is associated with the favorable behavior of bone tissue at the interface zone with pure titanium.
420 citations
TL;DR: It is concluded that the pro posed prophylactic program, including close supervi sion and correction by doctors and physiotherapists, significantly reduces soccer injuries.
Abstract: To study the efficacy of an injury prevention program in a randomized trial, 12 teams (180 players) in a male senior soccer division were followed up for 6 months. The 12 teams were allocated at random to two groups of six teams, one being given a prophylactic program and the other serving as control. The program was based on previous studies of injury mechanisms. It comprised (1) correction of training, (2) provision of optimum equipment; (3) prophylactic ankle taping; (4) controlled rehabilitation; (5) exclusion of players with grave knee instability; (6) information about the importance of disciplined play and the increased risk of injury at training camps; and (7) correction and supervision by doctor(s) and physiotherapist(s). The injuries in the test teams were 75% fewer than in the controls. The most common types of soccer injuries, sprains and strains to ankles and knees, were all significantly reduced. It is concluded that the proposed prophylactic program, including close supervision and correction by doctors and physiotherapists, significantly reduces soccer injuries.
311 citations
TL;DR: In this paper, the properties of carbide and nitride films were characterized by scanning electron microscopy and X-ray diffraction and through measurements of the microhardness and electrical resistivity.
265 citations
TL;DR: A series of N-aroyl d,l-amino acids were investigated with respect to direct optical resolution by high-performance liquid affinity chromatography on a stationary phase consisting of bovine serum albumin covalently bound to a 10-μm silica support as discussed by the authors.
237 citations
TL;DR: It is shown that macroscopically smooth-surfaced titanium can readily heal into bone without a soft tissue envelope, which could be of help for materials' choice and design of permanently fixed implants.
Abstract: Ten cylindrical implants, made of polycarbonate and covered with a 120-250-nm-thick layer of pure titanium, were implanted into each tibial metaphysis of five rabbits. Observation time was 12 weeks. The implants were surrounded by mature, living bone. No soft tissue intervened between bone and implant at any point. With TEM microscopy the titanium was shown to be bordered by a 20-nm-thick layer of proteoglycans, showing the characteristics of ground substance, and separating the collagen from the implant surface. Cells at the interface were likewise separated from the titanium by such a layer. Hydroxyapatite crystals were observed within the ground substance layer, occasionally seemingly in direct contact with the titanium. Normal mineralization was present 100-500 nm from the implant surface.While this study aims at defining interface anatomy, it also shows that macroscopi-cally smooth-surfaced titanium can readily heal into bone without a soft tissue envelope. This could be of help for materials' choice...
209 citations
TL;DR: The technique offers a simple method of quantifying ingested protein aggregates and of studying heterogeneity in phagocyte populations, and was found to be the best quenching agent of extracellular fluorescence when using ingested aggregated IgG.
208 citations
TL;DR: In this paper, the reactive sputtering of titanium in mixed ArN2 and CH4 discharges was studied by measuring the compositions of both the deposited films and the layers formed on the target.
176 citations
TL;DR: A new form of image estimator, which takes account of linear features, is derived using a signal equivalent formulation and shows that the method can improve the quality of noisy images even when the signal-to-noise ratio is very low.
Abstract: A new form of image estimator, which takes account of linear features, is derived using a signal equivalent formulation. The estimator is shown to be a nonstationary linear combination of three stationary estimators. The relation of the estimator to human visual physiology is discussed. A method for estimating the nonstationary control information is described and shown to be effective when the estimation is made from noisy data. A suboptimal approach which is computationally less demanding is presented and used in the restoration of a variety of images corrupted by additive white noise. The results show that the method can improve the quality of noisy images even when the signal-to-noise ratio is very low.
164 citations
TL;DR: A new algorithm for QRS delineation has been developed and the stability of the method is demonstrated for transitions between different waveform morphologies.
Abstract: A new algorithm for QRS delineation has been developed. Based on the envelope of the e.c.g. signal a delineation function is defined, which yields a single positive pulse for each complex. From this function the onset and end of the QRS or, alternatively, a fiducial point is determined. To remove low-frequency component such as S-T abnormalities without distortion of the QRS complex, a filter with time-varying characteristics is used. The accuracy of the method has been evaluated in a test set of different QRS complexes obtained from coronary care patients. For QRS onset, the standard deviation of the difference between automated and manual determination was 7 ms in normal beats and 14 ms in ectopic beats. With simulated noise added to each waveform an average dispersion of 7 ms was observed in the recognition of the QRS onset at a signal-to-noise ratio of 15 dB. The corresponding dispersion in the location of a fiducial point was 2 ms. Using simulated e.c.g. data, the stability of the method is demonstrated for transitions between different waveform morphologies.
152 citations
TL;DR: The suggestion that cGMP acts as a mediator of GTN-induced vascular smooth muscle relaxation is supported, as demonstrated in this study.
136 citations
TL;DR: In this paper, X-ray photoelectron spectroscopy (XPS) was used to characterize the conducting polymer BF4−-doped polypyrrole, and the results revealed that the pyrrole units are preserved in the polymer, the dopant occurs as BF 4− ions, there are four pyr role units per BF 4 − ion, and that electronic charge is extracted uniformly from all pyrrox units by the dopants ion.
01 Jan 1983
TL;DR: Assume that it should be possible to protect messages transmitted in a N-user network by encryption, and that the encryption can be performed by a public-key crypto system or by a conventional cipher.
Abstract: Assume that it should be possible to protect messages transmitted in a N-user network by encryption. The encryption can either be performed by a public-key crypto system or by a conventional cipher. In the first case there is no need for key distribution. In the second case we have two choices, either to distribute keys from a key distribution center or use a public key distribution algorithm.
TL;DR: In this paper, the authors measured the compositions of the films using Auger electron spectroscopy and their structure and morphology studied using X-ray diffraction and scanning electron microscopy respectively.
TL;DR: In this paper, the formation of surface compounds on the target leads to large reductions in deposition rate, and it is shown that the stable δ -TiN phase is formed on a target surface.
TL;DR: The concentrations of cholestero phospholipids and triglycerides were determined in plasma and in the HDL, HDL2, HDL3, LDL an VLDL fractions before and after one, three and si cycles of progestin treatment.
Abstract: Twenty-six postmenopausal women who had been on cutaneous oestradiol treatment for 3-6 months were given either 120 micrograms of 1-norgestrel (n = 13) or 300 mg of progesterone (n = 13) sequentially for another 6 months. The concentrations of cholesterol, phospholipids and triglycerides were determined in plasma and in the HDL, HDL2, HDL3, LDL and VLDL fractions before and after one, three and six cycles of progestin treatment. Already after 11 days on 1-norgestrel, the mean HDL cholesterol and the mean HDL phospholipid concentrations were reduced by 15%. The reduction of the HDL-lipids was mainly confined to the HDL2 fraction which was decreased by 25-30%. L-norgestrel also reduced the mean TG concentration both in the VLDL and the combined LDL + HDL fractions. Progesterone gave only minor changes of the plasma lipids and lipoproteins. Reduced HDL, especially HDL2, concentration, as induced by 1-norgestrel, might increase the risk for ischaemic heart disease. Therefore, it seems that, as regards the effects on the lipoproteins, progesterone might be more suitable than the 19-nortestosterone derivative 1-norgestrel for postmenopausal sequential hormonal therapy.
TL;DR: Laser Doppler flowmetry seems to be a useful tool in the further evaluation of the influence of spinal analgesia on the extent of tile associated sympathetic blockade.
Abstract: Changes in skin blood flow provoked by spinal analgesia were evaluated by laser Doppler flowmetry. This method permits a continuous and noninvasive measurement of the microvascular flow in the superficial skin layer. All recordings were made under control environmental conditions on 40 patients submitted to transurethral resection. During spinal analgesia a significant (P less than 0.001) reduction in skin blood flow was obtained in the shoulder and chest, while an increase (P less than 0.001) in skin blood flow was seen in the lower part of the body. In the postoperative period these changes still persisted, although they were less significant, indicating the individual duration of analgesia. The relations between intra-individual relative changes in skin blood flow and skin temperature during spinal analgesia were found to be virtually uncorrelated. Laser Doppler flowmetry seems to be a useful tool in the further evaluation of the influence of spinal analgesia on the extent of the associated sympathetic blockade.
TL;DR: It is suggested that the sound exposure criteria for industrial noise are not valid when discussing such sounds as are produced by acoustic instruments in a symphonic environment.
Abstract: The question has recently been raised as to whether the performance of symphony orchestra music involves a risk of sustaining hearing impairment. The following investigation presents a population study of 417 musicians, of whom 123 were investigated twice, at an interval of 6 years. Median values of screened tone thresholds were compared with a reference material, according to Spoor & Passchier-Vermeer (1969). The tone thresholds measured did not differ from the reference values although the actual sound exposure in some situations exceeded the permitted sound levels applied to industrial noise. We suggest that the sound exposure criteria for industrial noise are not valid when discussing such sounds as are produced by acoustic instruments in a symphonic environment.
TL;DR: Bupivacaine 0.75% (3 ml, 22.5 mg) in solution with glucose produced a more marked effect on the blood pressure than the other solutions tested, particularly suitable for hip surgery of long duration.
Abstract: Spinal analgesia with bupivacaine, tetracaine and mepivacaine was studied in 103 patients in two studies, one open and one double-blind. Injections were given with the patients sitting and they remained seated for 2 min after the injection. Regardless of the agent used, the mean cephalad spread of analgesia was T6-8 15 min after injection. Mepivacaine 4% (60 mg) in glucose produced analgesia and motor blockade of good quality but of short duration. Bupivacaine 0.5% and 0.75% and tetracaine 1%, all solutions with glucose, produced long-lasting blockades, tetracaine 14 mg having a longer duration of action than 15 mg bupivacaine. When 15 mg of bupivacaine was administered in solutions containing glucose, no difference in sensory blockade was seen, regardless of volume (2 or 3 ml, 0.75% and 0.5%, respectively) injected. 3 ml of bupivacaine 0.75% (22.5 mg) in glucose-free solution produced a very long-lasting blockade with deep motor engagement, particularly suitable for hip surgery of long duration. Bupivacaine 0.75% (3 ml, 22.5 mg) in solution with glucose produced a more marked effect on the blood pressure than the other solutions tested.
TL;DR: A new predictive coder, based on an estimation method which adapts to line and edge features in images, is described, and results are improved by pre- and postfiltering using a related noncausal form of the estimator.
Abstract: A new predictive coder, based on an estimation method which adapts to line and edge features in images, is described. Quantization of the prediction error is performed by a two-level adaptive scheme: an adaptive transform coder, and threshold coding in both transform and spatial domains. Control information, which determines the behavior of the predictor, is quantized using a simple variable rate technique. The results are improved by pre- and postfiltering using a related noncausal form of the estimator. Acceptable images have been produced in this way at bit rates of less than 0.5 bit/pixel.
TL;DR: A method is described for the analogue sampling of scattering angle in coherent and incoherent scattering processes, and the influence of coherent scattering, an often neglected process, can be estimated quantitatively.
TL;DR: The present study shows that laser Doppler flowmetry is a versatile method and the rat testis provides a suitable organ in the study of the origin and functional importance of these oscillations, and suggests that the recorded oscillations represent mainly local microvascular blood flow variations rather than variations in total testicular blood flow or tissue movements.
Abstract: We have earlier reported that local testicular blood flow, recorded by laser Doppler flowmetry, shows large oscillations with a frequency of 5-10 min-1. In the present study it is proposed that the recorded oscillations represent mainly local microvascular blood flow variations rather than variations in total testicular blood flow or tissue movements. The reasons for this are: (a) Blood flow simultaneously measured at two separate sites showed oscillations with different frequencies. (b) A local subcapsular injection of room-tempered saline under one probe site eradicated oscillations under that probe but not under another adjacent probe. (c) When the testicular capsule was split open, recordings of blood flow continued to show oscillations. (d) The amplitude of the oscillations was rather large (peak to peak value about 50% of mean flow value). No movements of the testicular surface were seen. A 20 min continuous infusion of 0.4 microgram/min noradrenaline did induce a decrease in plasma testosterone concentration, but did not change the mean blood flow. However, the oscillations nearly completely disappeared during the infusion period. The present study also shows that laser Doppler flowmetry is a versatile method and the rat testis provides a suitable organ in the study of the origin and functional importance of these oscillations.
TL;DR: In this paper, a theory for the development of a lamellar microstructure in the films containing two phases was proposed for the magnetron sputtering and reactive sputtering, and the observed microstructures were correlated with physical properties of the films.
TL;DR: The findings indicate that the presence of iron in lysosomes decreases the proton-retaining ability of their bordering membranes, possibly by way of enhanced metal (iron) catalyzed lipid peroxidation.
Abstract: Mouse peritoneal macrophages exposed to 60 microM Fe3+ in culture showed a pronounced decline in survival rate and an enhanced capacity for lipid peroxidation, as estimated by the formation of malondialdehyde. The iron-exposed cells contain secondary lysosomes loaded with iron as demonstrated by transmission electron microscopy, energy dispersive X-ray micro-analysis and the sulphide-silver method. The macrophages concentrated within their lysosomes the weak base acridine orange (AO) when the latter was added to the medium in a low concentration (1:10(5)). When cells were viewed under continuous illumination with short wave blue light in a fluorescence microscope, AO-exposed cells initially showed a brilliant red granular fluorescence and subsequently a progressive redistribution of AO into the cell sap and the nucleus with resultant green fluorescence. This redistribution of AO was associated with the disappearance of the normal granular reaction product pattern of the lysosomal marker enzyme acid phosphatase (AP), as demonstrated with a Gomori-type reaction, and later with cell death. The redistribution of AO and AP from the lysosomal vacuome to the cell sap under the influence of blue light occurred markedly more rapidly in macrophages containing iron loaded lysosomes than in control cells. The findings indicate that the presence of iron in lysosomes decreases the proton-retaining ability of their bordering membranes, possibly by way of enhanced metal (iron) catalyzed lipid peroxidation. It appears that leakage of AO signifies destabilization of the lysosomal membrane.
TL;DR: The ability of the pulmonary circulation to clear the blood of lidocaine is high, and that it is not affected markedly by those situations studied in the present investigation.
Abstract: Pulmonary uptake of lidocaine was investigated in patients before surgery, and aimed at elucidating the influence of general anaesthesia, the presence of another local anaesthetic agent in the blood, or the possible impact of lung insufficiency. When the lung uptake of lidocaine, injected as a bolus together with indocyanine green dye, was calculated as uptake at 95% pass of the dye, there were no statistically significant differences between the four groups. When the extraction in each of the arterial blood samples was calculated on the basis of the relation between relative concentrations, there were statistically significant differences, with a general tendency towards higher extraction of lidocaine in the awake, healthy volunteers, not given mepivacaine, compared to the other groups. In the group in whom mepivacaine was infused, the arterial concentration of mepivacaine increased transiently after the injection of lidocaine. This probably reflects a displacement of mepivacaine from binding sites for both agents. From this study, it is postulated that the ability of the pulmonary circulation to clear the blood of lidocaine is high, and that it is not affected markedly by those situations studied in the present investigation.
DOI•
01 Oct 1983TL;DR: The postoperative pain relief after a small dose (0.3 mg) of morphine or placebo injected intrathecally together with plain 0.75% bupivacaine for major hip surgery, was evaluated in a double blind study and found there was no pain or only mild pain in the postoperative period and did not require any administration of analgesia.
Abstract: The postoperative pain relief after a small dose (0.3 mg) of morphine or placebo injected intrathecally together with plain 0.75% bupivacaine (20 mg) for major hip surgery, was evaluated in a double blind study. It was found that in 17 patients of 23 belonging to the morphine group, there was no pain or only mild pain in the postoperative period and did not require any administration of analgesia. In the placebo group, all patients had marked pain experience and required an analgesic in the postoperative period. Complications due to the administration of morphine intrathecally included itching in two of 23 cases, as well as slow breathing in one case (7 breaths/min). This was eliminated by the injection of a small dose of naloxone.
TL;DR: The results indicate a causal relationship between adult coeliac disease and concomitant depressive symptoms which seems to implicate metabolic effects from pyridoxine deficiency influencing central mechanisms regulating mood.
Abstract: Signs of mental depression are typical in adults presenting with coeliac disease. The response to treatment was evaluated in 12 consecutive patients by means of the Minnesota Multiphasic Personality Inventory (MMPI), with surgical patients serving as controls. The coeliacs reported no change in depressive symptoms after 1 year's gluten withdrawal despite evidence of improvement in the small intestine. When retested after 3 years, however, after 6 months of 80 mg/day of oral pyridoxine (vitamin B6) therapy, they showed a fall in the score of scale 2 ('depression') from 70 to 56 (p less than 0.01), which became normalized like other pretreatment abnormalities in the MMPI. Cholecystectomy in the control subjects produced no alterations in the MMPI profile. The results indicate a causal relationship between adult coeliac disease and concomitant depressive symptoms which seems to implicate metabolic effects from pyridoxine deficiency influencing central mechanisms regulating mood.
TL;DR: Urinary recovery after oral intake in man and after intestinal load in rats and pigs indicates that the different-sized molecular components cross the intestinal epithelium at different rates, enabling characterization of the passive permeability properties of the mucosa.
Abstract: A novel method for the determination of different-sized polyethylene glycols (PEGs) in urine has been developed and applied to the study of intestinal permeability in man and animals. Macrogolum (PEG) 1000, a mixture of PEGs ranging from 634 to 1338 dalton, was used as probe molecules; these could be readily extracted from urine and analyzed by reversed-phase high-performance liquid chromatography. Urinary recovery after oral intake in man and after intestinal load in rats and pigs indicates that the different-sized molecular components cross the intestinal epithelium at different rates, enabling characterization of the passive permeability properties of the mucosa. Since altered intestinal permeability could underlie the pathogenesis of various diseases, this method could be of further use in investigative and clinical gastroenterology.
TL;DR: The study shows that the thresholds obtained with the two different techniques correlate well and that standard deviations for the test--retest difference are significantly lower in the computer-controlled situation.
Abstract: Ten normal-hearing subjects were evaluated with both manual and computer controlled audiometry using the ascending threshold determination method as proposed by ISO. The study shows that the thresholds obtained with the two different techniques correlate well and that standard deviations for the test--retest difference are significantly lower in the computer-controlled situation. The results also indicate that computer-controlled audiometry may be of importance in general clinical applications giving rapid and reliable threshold determination.
TL;DR: The electronic structure of the cleaved Ge(111)-(2.4-11.6 eV) surface has been studied with angle-resolved photoemission, with the use of photons in the energy range 7.4 and 11.6eV as mentioned in this paper.
Abstract: The electronic structure of the cleaved Ge(111)-(2\ifmmode\times\else\texttimes\fi{}1) surface has been studied with angle-resolved photoemission, with the use of photons in the energy range 7.4-11.6 eV. Similar to the Si(111)-(2\ifmmode\times\else\texttimes\fi{}1) surface, the dominating structure in the emission corresponds to a highly dispersive dangling-bond surface state. The initial-state energy, as a function of momentum parallel to the surface ${E}_{i}({k}_{\ensuremath{\parallel}})$ for this surface state, is presented along the $\overline{\ensuremath{\Gamma}}\ensuremath{-}\overline{J}\ensuremath{-}\overline{K}\ensuremath{-}\overline{\ensuremath{\Gamma}}$ lines in the (2\ifmmode\times\else\texttimes\fi{}1) surface Brillouin zone.
TL;DR: It is demonstrated that fine-grained incremental compilation is a relevant technique when implementing powerful debuggers an incremental programming environments and an incremental compiler for pascal has been implemented in the DICE system.