An in vitro investigation into the wear effects of unglazed, glazed, and polished porcelain on human enamel

A pBR322-based vector, pCI195, containing a 4.2-kb region of the conjugative transposon Tn919 was used as a vector for gene cloning in Clostridium difficile. The plasmid was found to integrate into the chromosome of a Bacillus subtilis strain that contained Tn916 delta E. Southern blot analysis of the recombinant demonstrated that pCI195 had inserted into Tn916 delta E by a recombination event. The transposon::plasmid structure could be transferred, by filter mating, from B. subtilis to C. difficile (at a frequency of 10(-8) per donor), where it entered the chromosome at a specific site. Segregation of plasmid and transposon markers was observed on transfer, although the Tn916 delta E::pCI195 was stably maintained in C. difficile. To demonstrate that pCI195 could be used for gene cloning in C. difficile, a 1.1-kb fragment of the C. difficile toxin B gene was cloned into pCI195 to generate pPPM100. Tn916 delta E::pPPM100 was transferred into a nontoxigenic C. difficile strain by filter mating, where it entered the genome at a specific site. pCI195 should be useful as a general cloning vector for C. difficile, as the transposon::plasmid structure could be transferred to different C. difficile strains. This is the first report of gene cloning in C. difficile.     

Fluoride content of prepackaged fruit juices and carbonated soft drinks

Epidemiological studies have established the beneficial effects of water fluoridation. Present dietary trends, however, indicate that many Australian children may consume more prepackaged fluids than actual tap water. The fluoride concentrations of a selection of carbonated soft drinks and prepackaged fruit juices were investigated. The results indicate that, in an optimal fluoride area such as Sydney, children who consume a consistent and large proportion of their fluids as carbonated soft drinks in cans, fruit juices and fruit drinks may not be receiving the full benefit of the water fluoridation.     

Proceedings: An investigation into the immunosuppressive properties of oestrogen

An investigation into the immunosuppressive properties of estrogen is reported. Normal and thymectomized mature male rats were given daily intradermal injections of .2 ml arachis oil containing 200 mcg estradiol-17beta/ml for 14 days. Lymphocytes from healthy men were incubated with the rat sera and lymphocyte subpopulations were identified by 3 surface markers: 1) cells forming rosettes with sheep erythrocytes (E-rosettes) as a measure of T lymphocytes, 2) lymphocytes with surface immunoglobulin identified by direct immunofluorescence (IgF), and 3) lymphocytes with receptors for C3 observed by a rosette technique employing sheep eryhrocytes treated with rabbit hemolytic serum and human complement (EAC-rosettes). Comparison of the effects of incubating cells with normal or treated rat serum revealed that E-rosettes dropped from 67.4 to 49% and that lymphocytes lacking all markers rose from 2.4 to 17.7%, respectively. The number of cells forming EAC-rosettes, bearing IgF or having both these markers did not change, however, it was apparent that a greater proportion of lymphocytes expressed both markers after incubation with estrogen-treated rat serum (25.7% compared with 12.1%). It appears that estrogen caused both decreased T lymphocyte response and enhanced B lymphocyte activity resulting in increased expression of related markers. None of these phenomena was apparent when lymphocytes were cultured with sera from estrogen-treated thymectomized rats, suggesting that estrogen affects the thymus such that a factor appears in the blood capable of causing changes in the immune response.     

An electrophysiological investigation into the monosynaptic H-reflex in the rat

Protein kinase C (PKC)-alpha and -betaII are expressed specifically and differentially in the septal formation. Following unilateral fimbria-fornix lesions, there was a marked reduction in punctiform PKC-alpha immunoreactivity in the lateral septum and in the number of PKC-betaII immunoreactive neurons in the medial septum and the lateral septum, while some PKC-alpha and PKC-betaII immunoreactive glia-like cells were observed in the lateral septum. The response of each PKC isozyme to this lesion supports the suggested role for PKC in the plasticity of the central nervous system.     

Why are poor comprehenders inefficient searchers? An investigation into the effects of text representation and spatial memory on the ability to locate information in text.

Good comprehenders were more efficient than poor comprehenders when they were required to locate specific pieces of information in a text, and there were qualitative differences in search strategies between the groups. However, the performance of the good comprehenders was more like that of poor comprehenders when they were required to search through a scrambled text, suggesting that their search was guided by their representation of the content of the text. Although the groups did not differ in performance on a test of spatial memory, or on their ability to remember the location of individual words in a text, the good comprehenders were better at remembering the order in which specific words appeared in a text. This finding again suggests that their superior search strategies may arise because of their better memory for the order of events in a text. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation into the immunochemical properties of the isoenzymes of human alkaline phosphatase

A study was carried out to investigate the immunochemical properties of the alkaline phosphatases present in liver, placenta, intestine, and kidney. Butanol extracts of the tissues were examined by antigen-antibody crossed electrophoresis, and the immunoprecipitates formed by the enzymes were identified by use of a specific stain for alkaline phosphatase. The results obtained revealed three immuno-chemical types of alkaline phosphatase, designated L, P, and PI respectively. The distribution of these enzymes among the tissues examined was as follows: type L was the only enzyme detected in liver extract and type P the only one detected in placental extract. The extracts of intestine and kidney both contained two isoenzymes, one of which was type L and the other type PI.     

An investigation into the role of waterproofing in a two-stage hypospadias repair

In our unit a two-stage procedure, using a full thickness preputial graft, has been adopted as the method of choice for the repair of hypospadias proximal to the coronal sulcus. In 1993 an audit was undertaken to establish our complication rate for this procedure. Twenty-two consecutive patients who completed a two-stage repair between January 1988 and December 1993 were studied. An unacceptably high fistula rate was identified (63%, 14/22 cases). Consequently our technique was modified by transposing a vascularised flap of preputial areolar tissue over the urethral suture line, at the time of urethroplasty. A second group of 22 consecutive patients, operated upon between January 1994 and July 1997, were subsequently investigated and a dramatic improvement in the fistula rate was demonstrated (4.5%, 1/22 cases). These cases represent a subgroup of almost 200 cases, which the senior author has managed over the last 10 years. The senior author undertook or supervised the surgery in all 44 cases, which were the focus of this study, and the introduction of a waterproofing layer represents the only change in technique.     

An investigation into modification of personality hardiness in staff nurses

Responsibilities of nurse educators include assisting nurses to adjust to a rapidly changing healthcare environment and demonstrating how these efforts are effective. In this article, the authors describe a study that measures the effects of teaching hardiness, a characteristic encompassing commitment, control, and challenge, to newly employed hospital nurses. The authors believe the study results indicate that instruction in hardiness is possible and may have an impact on morale.     

An investigation into the causes of absconding among black African breast cancer patients

OBJECTIVE: To discuss the complexities facing the researcher in attempting to determine reasons for the high rate of absconding from biomedical treatments by black African women diagnosed with breast cancer. DESIGN: Qualitative study based on in-depth interviews and participant observations of the informants, to ascertain attitudes, beliefs and practices of black African breast cancer patients with regard to the choice of healer. PARTICIPANTS: 10 black breast cancer patients, 4 African indigenous healers, 4 black lay persons, and 8 Groote Schuur Hospital members. SETTING: Radiation Oncology Department, Groote Schuur Hospital, Cape Town. RESULTS: The study revealed that various determinants affect black women's decision to abscond from biomedical breast cancer treatments. These determinants were based on social and cultural peculiarities. However, these findings did not explain the difference in absconding rates between black cervical (30%) and breast cancer (80%) patients. Although the two patient groups shared social, economic, and cultural backgrounds, their decisions with regard to biomedical treatments of cancer were remarkably different. CONCLUSIONS: The methods chosen for the research project provided a framework for a qualitative study of one ethnic group of breast cancer patients. However, the research framework failed to allow comparisons between breast and cervical cancer patients from the same ethnic backgrounds. Therefore, although the research findings revealed determinants affecting black breast cancer treatments, they do not explain the discrepancy between absconding rates of black cervical and breast cancer patients.     

An investigation into the observed sex difference in prevalence of unipolar depression.

The rates of occurrence of unipolar depression as measured by self-report and by diagnosis based on semistructured interviews were examined in a longitudinal study with 312 men and 686 women aged 18 yrs and over. Number of new cases, average age of onset, and average duration of episodes were comparable in men and women, but women with a history of previous depression were much more likely to become depressed again than men with a similar history. Data on a large number of demographic and psychological variables were collected through such measures as the Brief Symptom Inventory. Controlling for these factors (both singly and in combination) did not eliminate the sex difference in unipolar depression. Neither the artifact hypothesis (according to which the "true" prevalence of depression is equal for men and women) nor the psychosocial hypothesis (according to which women are more disadvantaged on relevant psychosocial variables) was supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation into the leaching kinetics of cobaltite ore with ferric sulfate solutions

A method for the extraction of cobalt from cobalt-arsenic-sulfide (cobaltite) ores or concentrates has been identified. The method utilizes an atmospheric oxygen-acidic ferric sulfate leach, at temperatures up to 373 K (100°C), to place the cobalt in solution. Extraction of 80 pct of the cobalt was obtained within 24 h and the tests indicate that greater and more rapid extractions are possible. Experiments were performed to assess the effects of temperature, ferric concentration, acid concentration, particle size, oxygen addition, and silver addition on the kinetics of cobaltite and chalcopyrite dissolution. formerly Graduate Student, University of Idaho     

An investigation into factors affecting proteocine production by Proteus isolates

Proteocine production was found to the influenced by the medium used, the temperature of incubation and the length of incubation. Different amounts of proteocine were produced in different media. Production in liquid media was maximum in proteose-peptone No. 3 (Difco). This medium gave a very high titre (1:10000) of proteocine when inoculated with the producer strain, and the aerated culture was induced with mitomycin C. Therefore a method of producing a high titre proteocine was developed using proteosepeptone No. 3 (Difco) and cultural conditions of 25 degrees C for 24 hours.     

On misattributing good remembering to a happy past: An investigation into the cognitive roots of nostalgia.

Reflections on the past are often accompanied by an experience of nostalgia, or positive sentiments about some prior stage of one's life. In the current study, we provide evidence suggesting that nostalgic experiences may occur because of positive feelings that accompany the act of successful recall, rather than reflecting the true nature of the past. In a series of experiments, we employed an encoding manipulation to cause some words to support more detailed recollections than others. In turn, we measured the effect of these manipulations on judgments of both pleasantness and the emotional valence of a prior stimulus encounter. We demonstrate that recollections rich in meaning are unique in biasing people to judge having previously seen a stimulus in an emotionally positive context. In contrast, pleasantness judgments appear to be guided primarily by perceptual fluency. Overall, our results are consistent with the notion that the subjective experience of nostalgia represents a misattribution of successful remembering to a pleasant past. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of sex differences in spatial ability: Mental rotation of three-dimensional objects.

Presented 2-dimensional computer-generated representations of 3-dimensional objects in pairs to 20 male and 20 female right-handed undergraduates. Ss were given 15 sec to make a same-different judgment of the objects, one of which was rotated 0°, 40°, 80°, 120°, or 160° from the other. Ss were also assessed on 2 standard spatial ability tests (the Spatial Relations subtest of the Differential Aptitude Tests, Form L, and the Standardized Road-Map Test of Direction Sense) and a verbal-imagery questionnaire. Analyses of the data showed that men were more accurate than women, and that the slope of the function relating response time to degree of rotation was steeper in women. There was a significant linear relation between performance and the degree of rotation. Rate of rotation and accuracy correlated with the other tests of spatial ability. Response time slope correlated with imagery in men but not in women, suggesting that frequent use of visual imagery was related to mental rotation rate in men, but not in women. There were no clear relations between performance and the strategy Ss professed to use in doing the mental rotation. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation into the feasibility of parental participation in the nursing care of their children

Family-centred care has been recognized as a basic tenet of paediatric nursing for some time because it is believed that children benefit from the continuous presence of their patents. It is for this reason that the concept of care by parents has evolved. Although such a philosophy is beneficial for the child, it has undoubtedly evolved due to low staffing levels, and in such an environment the guidelines for safe practice are easily called into question. In the wake of a new paediatric oncology ward, it was decided to consider instituting care by parents. In an effort to do this in a structured way, it was decided to make our practice research based. A teaching tool was formulated and five mothers who presented consecutively to the paediatric oncology ward were taught how to administer intravenous antibiotics to their child. Mothers' views on the teaching programme were sought using taped interviews, and the data were analysed using grounded theory. This methodology allowed a theoretical framework based on realistic data to emerge, and the resultant themes provided a valuable insight into mothers' views on the subject. It emerged that nurses' attitudes towards care by parents require clarifying and that changes need to take place if this concept is to be taken on board. Negotiation to allow mutual understanding between parents and nurses is essential to the successful implementation of such a scheme.     

An investigation into the relationships between area social characteristics and road accident casualties

This paper reports on the analysis of a data base created by merging road casualty information and census data for the former Lothian region in Scotland. The data base was established by assigning resident postcodes to each casualty record and relating these postcodes to the census data for the relevant census output area. Initially, consideration was given to the relationship between casualty frequencies and the distance of the accidents from the zones of residence. As might be anticipated, the casualty frequencies were higher nearer to the zones of residence, possibly due to higher exposure. Subsequently, the relationships between casualty rates and social deprivation indicators for the casualties' zone of residence were investigated. In general it was found that the casualty rates amongst residents from areas classified as relatively deprived were significantly higher than those from relatively affluent areas.