Showing papers by "Cardiff University published in 1975"

Calcaneo-valgus deformity

Abstract: A discussion of the essential deformity in calcaneo-valgus feet develops a theme originally put forward in 1961 on the relapsed club foot (Evans 1961). Whereas in the normal foot the medial and lateral columns are about equal in length, in talipes equino-varus the lateral column is longer and in calcaneo-valgus shorter than the medial column. The suggestion is that in the treatment of both deformities the length of the columns be made equal. A method is described of treating calcaneo-valgus deformity by inserting cortical bone grafts taken from the tibia to elongate the anterior end of the calcaneus.

Masticatory function-a review of the literature: (II) Speed of movement of the mandible, rate of chewing and forces developed in chewing.

Abstract: (1) Speed of movement of the mandible The speed of the masticatory movement is the speed developed by the mandible as it approaches or moves away from the maxilla. In a typical chewing stroke the mandible moves from the open position in an upward direction and, as contact is made with the bolus, the closure rate decreases and in most cycles there is a pause in occlusion. The mandible then drops rapidly and there is a gradual decrease in movement again as the mouth nears maximum opening. Shepherd (1960) discussed speed of movement of the mandible but did not try to assess it. In dentate and edentulous subjects the speed varied in different parts of the cycle and also from subject to subject. During each cycle a pause that averaged between 0-1 and 0-2 s occurred at the contacting position. WoelM, Hickey .& Allison (1962) found, in a study of edentulous subjects, that the chewing speed was more constant with rubber than with peanuts because of its .unchanging consistency, and that the closing stroked were slower than the opening strokes. As the jaw closed and the cusps neared contact with the food, the closure rate decreased. The motion slowed down even more as the bolus was crushed and then there was a pause of about 0-16 s before the jaw rapidly opened. Ahlgren (1966) recorded great individual variation of speed and acceleration in the mastlcalSry cycle in dentate children and showed that the mandible accelerated in the beginning of the opening phase and closing phase. Deceleration was especially marked when the mandible approached the intercuspal position and at the turning point between the opening and closing phase there was no pause. The mean speed of the masticatory movements in gum chewing and in carrot chewing was 64-0 mm/s and 75-0 mm/s respectively.

The properties and extracellular location of 5'-nucleotidase of the rat fat-cell plasma membrane.

Abstract: 1. A phosphohydrolase specific for 5'-nucleotides was characterized by using a particulate fraction from isolated fat-cells. 2. The activity of intact cells towards 5'-AMP was studied. 3. The activity in either situation had the same KM for AMP (45 muM) and was inhibited by low concentrations of ATP (less than 50 muM), but less potently by the ATP analogues AMP-P(CH2)P(adenylyl (beta gamma-methylene)diphosphonate) and AMP-P)NH)P (adenylylimidodiphosphate). 4. Homogenization of intact fat-cells caused no increase in activity and at least 85% of the activity was recovered in the particulate preparation. 5. The preparation of fat-cells used in this work was not freely permeable to AMP. 6. The ability of intact fat-cells to hydrolyse AMP implies that 5'-nucleotidase is an ectoenzyme in fat-cells. 7. Concentrations of ATP 100 times lower than intracellular concentrations inhibit the enzyme when added extracellularly to intact fat-cells, implying that this effect is also medicated at the extracellular face of the membrane. 8. Antibodies raised to whole liver cells and whole fat-cells inhibit 5'-nucleotidase in intact cells. 9. Incubation of intact fat-cells with adrenaline (1 mug/ml) or insulin (50 mui.u./ml) failed to alter the KM or Vmax. of the enzyme.

The social structure of violence in childhood and approval of violence as an adult

Abstract: Data from a national sample survey conducted for the Commission on the Causes and Prevention of Violence are used to investigate the relationship of three aspects of exposure to violence in childhood (observing violence, being a victim of violence, and committing violence) with approval of violence as an adult. Those who experienced violence as a child tended to favor the use of violence to achieve personal and political ends. However, there was no correlation between childhood violence experience and approval of the use of violence to settle conflicts between nations. It is concluded that the amount of violence experienced in childhood by members of a society is one of the factors contributing to the development and maintenance of cultural norms supporting the use of violence in face-to-face situations. VioLit summary: OBJECTIVE: The purpose of this study by Owens and Straus was to address the extent to which violence during childhood is associated with the future approval of the use of violence in three areas - nationally, politically, and interpersonally. METHODOLOGY: This study used information from 1,176 interviews conducted in 1968 by Baker and Ball for the President's Commission on the Causes and Prevention of Violence. The sample was selected using an area probability random sampling method. Telephone interviews were conducted on people 18 years or older. A review of current attitudes regarding the approval and legitimacy of violence in society was conducted. The following three views were explored. First, the greater the observation of violence as a child, the greater the approval of violence as an adult. Secondly, the more a child is a victim of violence in childhood, the greater their approval of violence as an adult. Thirdly, the more a child commits violent acts, the greater their approval of violence as an adult. Because childhood exposure to violence can be interpreted differently, measurement of the approval of violence was correlated and separated into three indexes, national violence (preserving integrity and honor), political violence (means to achieve political ends), and interpersonal violence (face-to-face between friends or acquaintances). Questions on the national index asked how respondents felt about their nation using violence in cases of war, and killing civilians when it was unavoidable. The political index asked for approval of violence used on persons who were armed against tax laws, critical of the government, war protestors, individuals who threaten senators, and the shooting of innocent people. The interpersonal index requested approval of violence when any of the following occurred: a parent spanking or beating a child if the child was noisy, disobedient, expelled, or had broken a law; slapping one's spouse if they were argumentative, insulting, flirting, or unfaithful; shooting one's spouse if unfaithful; a teacher hitting students if they were noisy, disobedient, destructive, or had hit the teacher; a policeman striking a citizen if they acted obscene, were demonstrating, suspected of murder, tried to escape, or attacked a policeman; a policeman shooting a citizen if escaping, attacking, or threatening with a gun; a teenager punching another teenager if disliked, ridiculed, challenged, or hit; a man striking another adult male if he were drunk, had hit a child, had beat a women, or had broken into his home; a man choking a stranger if he had hit a child, had beat a women, or had committed assault and robbery. Measurement procedures included selecting the data that indexed the variables, ranked the responses, summed the responses, analyzed indexes by item, and eliminated correlations falling below.20. Complete information regarding methodology is available in Owens, D.J. (1973), Experience with Violence in Childhood and Adult Violence Approval, Unpublished Master's Thesis, University of NewHampshire, Dur item-total correlations. FINDINGS/DISCUSSION: The three independent variables, interpersonal violence observed as a child, interpersonal violence received as a child, and interpersonal violence committed as a child were all intercorrelated based on exposure to violence. The results indicated a relationship between each variable which, in the authors' view, justified the existence of a social structure of violence in childhood. However, because the correlations were low (.41 to.63), they were reexamined as separate functions. Moderate correlation was found between the approval of interpersonal violence as an adult and all three indexes of exposure to violence as a child. Although moderate, these correlations were higher than expected, especially when considering that time and other factors would have reduced the correlations between the independent variables (childhood exposure) and the dependent variable (the approval of violence). When the respondent was a victim of the violence, instead of the expected disapproval of violence, the opposite was reported. The authors stated that one can assume that the victim observed the perpetrator getting what they wanted by means of violence. Thus, regardless of the exposure to violence in childhood - observing, being victims, or committing acts of violence - the approval of violence was viewed as a learning situation. The child observed the end results, internalized a view of moral correctness, and learned the reward of violent behavior. Women tended not to have as strong an association of progressing from exposure to approval, as did men. It was assumed that women have different expectations with regard to violence. Women are taught to disapprove of violent behavior. In addition, they cannot make use of violence nor defend themselves against violence, in the same way that men can. No significant results were noticed when controlling for socioeconomic status. Also, educational background had no effect between the association of exposure and subsequent approval of violence. When controlling for sex, SES, and education level, childhood exposure did not correlate significantly with the approval of national violence. The authors reported that behaviors learned from exposure to childhood violence, and subsequent approval of assaulting family and friends, did not extrapolate to situations of war between nations. Political violence was moderately correlated with exposure to violence in childhood. This exposure provided people with behavior models for acts of political violence. Overall, the data in this study displayed a strong correlation between exposure to violence as a child with approval of interpersonal violence as an adult. Approval of political violence was not as strong, and national violence was virtually uncorrelated to exposure of violence. Factors such as SES and education failed to effect results; however, males displayed consistently higher correlations than females. The authors suggested that this paper is proof of the role-model theory of witnessing violence as a child and future approval as an adult. However, role-model behavior was not a factor in the approval of national acts of violence. The authors hoped their results would help in reducing the approval of interpersonal violence and violence in society. In conclusion, the authors stated that this study's findings were consistent with the social-structure theory of violence. This theory posits that the greater the presence of violence in the social structure during childhood, the more the person learns to use violence; and for any set of behaviors characteristic of a population, there will develop a normative counterpart that rationalizes and justifies such behavior. The authors suggested that the high level of violence reported during adolescence is related to the "culture of violence" observed in our society, and that any means to alter violence through education will also depend upon the support from and the change in our social structure. AUTHORS' RECOMMENDATIONS: The authors suggested that future research should investigate confounders such as: (1) individual's belief in society and their belief in the goodness or badness of specific groups and humanity overall; (2) the situational determinants of being victimized, the expectations of loved ones; and (3) other possible resources that might be available for resolution. The authors thought that longitudinal cross lagged correlation designs could help match measures of experiences with those of actual violence. They also expressed limitations to the scope of this paper, specifically in the use of the phrase "violence as a means of social control." Future studies need to address violence, as it is defined in expressive or instrumental behavior; or as it is deemed to have social legitimacy. (CSPV Abstract - Copyright © 1992-2007 by the Center for the Study and Prevention of Violence, Institute of Behavioral Science, Regents of the University of Colorado) KW - Child Witness KW - Child Violence KW - Child Victim KW - 1960s KW - Violence Effects KW - Psychological Victimization Effects KW - Witnessing Violence Effects KW - Exposure to Violence KW - Adult Perceptions KW - Adult Attitudes KW - Long-Term Effects KW - Childhood Experience KW - Childhood Victimization KW - Social Structure KW - Theory KW - Attitudes Toward Violence Language: en

A hydrodynamic mechanism for the disintegration of Saccharomyces cerevisiae in an industrial homogenizer

Abstract: Amongst the commercial type of homogenizers the Manton-GaulinAPV homogenizer (APV Company Ltd., Crawley, Surrey, England) which is generally being used for other purposes than cell disintegration processes, has recently been proved to be effective for the breakage of yeast cells. To understand fully the disintegration process occurring in such machines it becomes necessary to describe their functions through mathematical expressionsbased on a realistic hydrodynamic model. A mathematical expression describing the protein release at an applied pressure has been derived from an energy balance in the homogenizer combined with the size distribution function of yeast cell population. This expression has been confirmed experimentally under conditions where it shows that turbulence is the controlling factor in the system. Furthermore it indicates the area where more investigations are needed to improve the efficiency of the process of disintegration.

Internal regulation of iron absorption.

Abstract: MCCANCE and Widdowson1 concluded that body iron content is regulated by variation in the amount absorbed and not by variation in excretion, and many workers have since attempted to define the factors which relate iron absorption to the needs of the body. Although there is a large body of data on the intracellular mechanisms of absorption2 this has not advanced our understanding of the physiology of regulation.

Characterization of pulmonary surfactant from ox, rabbit, rat and sheep.

Abstract: 1. Pulmonary surfactants from ox, rabbit, rat and sheep were isolated and analysed. 2. All preparations had a high anenoic phosphatidylcholine content and would produce stable surface tensions of 0.01 Nm-1 or less. 3. Protein content was 8-18% of the dry weights. A number of proteins were observed; their overall composition were high in hydrophobic amino acid residues. 4. Lipid content varied from 79% (ox) to 90% (rabbit) with phosphatidylcholine representing from 58% (sheep) to 83% (rabbit) of the total lipid. The surfactant preparations were rather similar in lipid composition except that sheep surfactant contained about 10% lysophosphatidylcholine. 5. Hexadecanoic acid was the principal fatty acid. It was particularly high in phosphatidylcholine. 6. Phosphatidylglycerol was a minor constituent of all surfactants but phosphatidyldimethylethanolamine was not detected.

The development of an abrasion testing machine for dental materials.

Abstract: Wear testing should be an important part of the investigations into the physical and mechanical properties of some dental materials. It has, however, largely been ignored because of conflicting and unreproducible results. It was decided, therefore, to review the work done by other researchers and to examine the human masticatory cycle, and then present new parameters to design and construct a new dental abrasion testing machine. This new machine is described in detail and its capabilities briefly illustrated.

Median rhomboid glossitis. Candidiasis and not a developmental anomaly.

Abstract: Infection by Candida Albicans was found in all biopsies taken from ten patients presenting with midline lesions of the tongue which clinically presented as median rhomboid glossitis.

Carbohydrate binding proteins involved in phagocytosis by Acanthamoeba.

Abstract: THE soil sarcodinid Acanthamoeba castellanii grows readily in axenic culture1,2 or in monoxenic conditions with a variety of bacteria as food organisms3. The reduced growth of this organism in the absence of particulate material4 suggests that even under axenic conditions the formation of phagocytic vesicles is important in the uptake of nutrients, as in Tetrahymena5. We present evidence that the preferential uptake by A. castellanii of horse red blood cells over those from other sources6 is caused by binding of these cells to carbohydrate sensitive sites on the surface of the amoebae, and that these sites may function in the same way in the amoeba's natural habitat.

The characteristics of ferritin from human tissues, serum and blood cells.

Abstract: 1. The properties of ferritin in serum have been compared with those of ferritin from a number of tissues including blood cells. On anion-exchange chromatography with DEAE-Sephadex, the behaviour of human heart ferritin is different from that of liver, kidney or spleen ferritin. Reticulocyte ferritin appears to have similar characteristics to heart ferritin. 2. Serum ferritin from normal subjects and patients with various degrees of iron load, leukaemia or liver disease all have a much lower affinity for the anion-exchange column that any tissue ferritin, suggesting a difference in isoelectric point. The elution point of serum ferritin from patients with acute myeloblastic leukaemia is significantly different from normal. 3. Density gradient centrifugation in sucrose showed that ferritin in leucocyte extracts and partially purified ferritin from the serum of two patients with iron overload behaved as apoferritin rather than the iron-rich protein. 4. The results suggest that ferritin is modified during its entry into the plasma and that even in cases of iron overload the iron content of serum ferritin may be low. The findings are of importance in considering the origin of plasma ferritin, the clearance of ferritin from plasma and its role in iron metabolism.

Sweeping flight and soaring by albatrosses

Abstract: ALBATROSSES can fly over the sea for a long time without flapping their wings. Raleigh1 worked out a suitable method, known as dynamic soaring, to account for this and Idrac2 showed that this was the method used by the birds.

The interfacial factor in the heat‐induced conversion of chlorophyll to pheophytin in green leaves

Abstract: The rates of the conversion of chlorophyll to pheophytin in the green leaves of common vegetables and other plants at different temperatures in buffered electrolyte systems were studied. Kinetic measurements showed that the conversion only occurred above a threshold temperature of 50–60 °C and was most probably a pseudo-first order reaction. Rates were found to be proportional to √[H+]. The dependence of the rate of conversion upon species, temperature and electrolyte type can be explained on the basis of a heat-induced metamorphosis of the chloroplasts to a smectic mesophase which occludes the chlorophyll. The rate of the reaction then depends on the transfer of hydronium ions across the interface and can be largely controlled by modifying the interfacial potential.

Analysis of droplets from iso‐atomic solutions as a means of calibrating a transmission electron analytical microscope (TEAM)

Abstract: SUMMARY This paper describes a spraying method of producing iso-atomic droplets (≅3 μm diameter) of uniform size, distribution and chemical composition. These droplets were used to calibrate a TEAM system operated under given conditions, so that the relative sensitivity of the instrumentation for the elements Na, Mg, P, S, (Cl), K, Ca and Co (‘overall sensitivity factors’) could be determined. These factors (15, 40, 83, 90, (43), 104, 109, 100% respectively) were used to convert observed X-ray intensity ratios from standard droplets to relative amounts of elements with a fair degree of accuracy (error generally less than ± 10%). It was proposed that the sampling and quantification methods could be applied for the absolute quantitative bulk-analysis of fluids and tissues (after solubilization) with an introduced reference element, e.g. cobalt, and potentially to the study of relative elemental ratios in fluid microvolumes and in biological thin sections.

Rebreathing in a t-piece: volunteer and theoretical studies of the jackson-rees modification of ayre's t-piece during spontaneous respiration

Abstract: SUMMARY The Jackson-Rees modification of Ayre's T-piece was examined experimentally and theoretically to see what effects the theoretical restrictions of Onchi, Hayashi and Ueyama (1957) (1 : 1 i: E ratio, zero deadspace volume) and the square-wave approximation of Mapleson (1958) may have had on the calculated critical fresh-gas flow rate necessary to prevent rebreathing of exhaled alveolar gases. In the experimental examination six conscious alert volunteers breathed through the system as the fresh-gas flow rate was varied in steps, and their ventilation was recorded at each value. Assuming that under rebreathing conditions a normal arterial P co 2 is maintained by hyperventilation, this experimental situation is identical with one of the two considered theoretically by assuming sine-wave inspiratory and expiratory waveforms, zero longitudinal mixing in deadspace volumes and perfect mixing in the alveoli. Agreement between experimental and theoretical results justifies the assumptions made in the theoretical analysis and the results indicate that a fresh-gas flow rate of about twice the normal ventilation is necessary to eliminate rebreathing completely from the Jackson-Rees modification of Ayre's T-piece. The exact requirement depends on the deadspace/tidal volume (VD/VT) and I: E ratios. The onset of hyperventilation at lower fresh-gas flow rates is gradual and, in spontaneous breathing with VD/VT approximately equal to 40% and i: E ratio=1 : 1.2, is only 10—20% at a fresh-gas flow rate of 1.5 times the normal ventilation