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At least 487 records · Page 27Linked to original sources

PubMed2005

Psychosocial Experiences of East and Southeast Asian men who use gay Internet chatrooms in Toronto: an implication for HIV/AIDS prevention.

OBJECTIVES: In recent years we have witnessed an increase in Asian men who use gay Internet chatrooms in Toronto. Previous research has shown that many men who had sex with men (MSM) sought sex partners through the Internet and that meeting sex partners via the Internet increases sexually transmitted infection (STI) and HIV risk. This study aims to (1) explore psychosocial issues relating to Asian men who use gay chatrooms and (2) identify culturally appropriate HIV prevention strategies for this population. DESIGN: In-depth interviews were conducted with a total of 21 East and Southeast Asian men who used Internet gay chatrooms. Unstructured, open-ended questions were used to obtain narrative data to help understand their lived, psychosocial experiences of gay chatrooms. Transcripts of the interviews were read to highlight themes and concepts. RESULTS: Analysis revealed complex lived, psychosocial experiences of Asian men who use gay chatrooms in Toronto. They tended to be socially isolated and highly marginalized, which had led to intense needs for social connections and thus left some Asian men vulnerable to sexual exploitation. Although they were fully aware that they should use condoms in anal intercourse with a casual partner, they had some misconceptions about HIV. Moreover, they rarely, if ever, used condoms in oral sex with a casual partner, which might leave them vulnerable to STI. CONCLUSIONS: It is important for service providers to continually provide accurate information about STIs and HIV/AIDS including how they can be contracted. However, HIV prevention strategies for this population must also address issues relating to social isolation and marginalization in order to combat the spread of HIV/AIDS effectively. This can be accomplished by an online peer support program.

Asia, Southeastern↗

PubMed1994

What's distinctive about a distinctive face?

In this study we examine the relationship between objective aspects of facial appearance and facial "distinctiveness". Specifically, we examine whether the extent to which a face deviates from "average" correlates with rated distinctiveness and measures of memorability. We find that, provided the faces are rated with hair concealed, reasonable correlations can be achieved between their physical deviation and their rated distinctiveness. More modest correlations are obtained between physical deviation and the extent to which faces are remembered, either correctly or falsely, after previous study. Furthermore, memory ratings obtained to "target" faces when they have been previously seen (i.e. "hits") do not show the expected negative correlation with the scores obtained to the same faces when acting as distractors (i.e. "false positives"), though each correlates with rated distinctiveness. This confirms the theory of Vokey and Read (1992) that the typicality/distinctiveness dimension can be broken down into two orthogonal components: "memorability" and "context-free familiarity".

Adolescent↗

PubMed2006

Monte Carlo correction factors for a Farmer 0.6 cm3 ion chamber dose measurement in the build-up region of the 6 MV clinical beam.

Reference dosimetry of photon fields is a well-established subject and currently available protocols (such as the IAEA TRS-398 and AAPM TG-51) provide methods for converting the ionization chamber (IC) reading into dose to water, provided reference conditions of charged particle equilibrium (CPE) are fulfilled. But these protocols cannot deal with the build-up region, where the lack of CPE limits the applicability of the cavity theorems and so the chamber correction factors become depth dependent. By explicitly including the IC geometry in the Monte Carlo simulations, depth-dependent dose correction factors are calculated for a PTW 30001 0.6 cm(3) ion chamber in the build-up region of the 6 MV photon beam. The corrected percentage depth dose (PDD) agrees within 2% with that measured using the NACP 02 plane-parallel ion chamber in the build-up region at depths greater than 0.4 cm, where the Farmer chamber wall reaches the phantom surface.

Calibration↗

PubMed1989

The effect of 2% chlorhexidine digluconate irrigation on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets.

Eight patients with moderate periodontitis volunteered to participate in a study to assess the effect of subgingival 2% chlorhexidine irrigation, with and without scaling and root planing, on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets. Each quadrant was required to have at least one site with a probing depth of 6 mm or greater and bleeding on probing. The patients were treated following a randomized four quadrant design: one quadrant received no treatment; a second quadrant received scaling and root planing only; a third quadrant received chlorhexidine irrigation only; the fourth quadrant received scaling and root planing, plus chlorhexidine irrigation. Sites to receive chlorhexidine were irrigated at 0, 1, 2, and 3 weeks. Clinical and microbiological indices were measured and recorded at 0, 5, 7, 11, and 15 weeks. The clinical parameters measured included; Plaque Index (PI), Gingival Index (GI), probing depth (PD), Bleeding Tendency (BT), and attachment level (AL). The attachment level was measured using an occlusal stint as a fixed reference point. The level of Bacteroides gingivalis was measured by labeling the plaque sample with a polyclonal fluorescent antibody. The plaque smear was then read using a fluorescent microscope at 1000 magnification. The Spearman Rank-Order Correlation was used to determine the relationship between parameters at baseline. The effects of the treatment groups were compared using the Neuman-Keuls Multiple Comparison Technique. The results showed that a positive correlation existed between B. gingivalis (rs = 0.68) and Bleeding Tendency and between P1I (rs = 0.77) and GI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

[Development and dosimetry of a 125 iodine applicator for brachytherapy of intraocular tumors].

Due to the low gamma energy (27-35 ke V), iodine 125 is especially suitable for brachytherapy of intraocular tumors. 125I is available as encapsulated seeds. Applicators can be individually loaded with these seeds to accommodate the shape of the tumor as much as possible. To measure the depth-dose distribution LiF thermoluminence detectors (TLDs, 1 mm3) are embedded in an RW-1 eye phantom at various distances and directions from the high active plaque positioned at the top of the phantom. To obtain the three-dimensional dose distribution, the TLDs are read after exposure for the appropriate time period. Based on experimental measurements of the 125I plaque, a computer program is developed to calculate the dose distribution within the eye and the radiation time for intraocular tumors. These results are very similar to those obtained when using mathematical equations published in the literature. In summary, three-dimensional dose distribution at various distances from an 125I eye plaque has been experimentally determined using a new method. This is an important prerequisite for introducing 125I plaques into the treatment of intraocular tumors.

Brachytherapy↗

PubMed1995

Deep-depth chemical peeling.

Although a wide range of peeling agents are available, few can provide the dramatic improvement that is seen with phenol-based peeling. The nonoccluded phenol-based technique described in this article has been used successfully for over 20 years. Due to the deeper degree of injury and more involved recovery period, the surgeon will be best served by not only reading about this technique, but also observing an experienced surgeon.

Chemexfoliation↗

PubMed2006

Comparison of simulated periodontal bone defect depth measured in digital radiographs in dedicated and non-dedicated software systems.

OBJECTIVES: To compare simulated periodontal bone defect depth measured in digital radiographs with dedicated and non-dedicated software systems and to compare the depth measurements from each program with the measurements in dry mandibles. METHODS: Forty periodontal bone defects were created at the proximal area of the first premolar in dry pig mandibles. Measurements of the defects were performed with a periodontal probe in the dry mandible. Periapical digital radiographs of the defects were recorded using the Schick sensor in a standardized exposure setting. All images were read using a Schick dedicated software system (CDR DICOM for Windows v.3.5), and three commonly available non-dedicated software systems (Vix Win 2000 v.1.2; Adobe Photoshop 7.0 and Image Tool 3.0). The defects were measured three times in each image and a consensus was reached among three examiners using the four software systems. The difference between the radiographic measurements was analysed using analysis of variance (ANOVA) and by comparing the measurements from each software system with the dry mandibles measurements using Student's t-test. RESULTS: The mean values of the bone defects measured in the radiographs were 5.07 mm, 5.06 mm, 5.01 mm and 5.11 mm for CDR Digital Image and Communication in Medicine (DICOM) for Windows, Vix Win, Adobe Photoshop, and Image Tool, respectively, and 6.67 mm for the dry mandible. The means of the measurements performed in the four software systems were not significantly different, ANOVA (P = 0.958). A significant underestimation of defect depth was obtained when we compared the mean depths from each software system with the dry mandible measurements (t-test; P approximately equal to 0.000). CONCLUSIONS: The periodontal bone defect measurements in dedicated and in three non-dedicated software systems were not significantly different, but they all underestimated the measurements when compared with the measurements obtained in the dry mandibles.

Alveolar Bone Loss↗

PubMed2006

The paradoxical reliance on allopathic medicine and positivist science among skeptical audiences.

A number of studies have found an association between what people see, hear and read in the mass media and their corresponding actions and beliefs. This link has been demonstrated both at the micro and at the macro levels of analysis. However, when people are asked directly about the impact of mass media they tend to deny that they are personally affected. In fact, they tend to describe themselves as critical and skeptical media consumers. The purpose of this paper is to explore this contradiction through 12 in-depth focus group discussions undertaken in Ontario, Canada in 2004. Findings from the focus group interviews confirm earlier research in that people claimed that they were not susceptible to media influence. At the same time as they said that they took information from the mass media "with a grain of salt", they articulated sophisticated and nuanced accounts of how and why they evaluated some information as good and some as bad. In general they evaluated media stories on the basis of the values of allopathic medicine and positivistic science. Moreover, in the context of the focus groups and their explicit comments on their skepticism, they discussed health information from the magazine articles that they were given to read (on either HIV/AIDS, Alzheimer's disease, or a heart disease). Possible explanations for these paradoxical findings are discussed.

Attitude to Health↗

PubMed1993

Reduction in number of corpora amylacea with advancing histological changes of glaucoma.

Retina and optic nerve of eyes enucleated due to an iris ring melanoma or a malignant melanoma of the ciliary body were studied to investigate the correlation between corpora amylacea count and glaucoma stages. Ten eyes from ten patients [age: 62.3 +/- 13.0 (mean +/- SD); range 43-84 years] were used for the present study. Eight eyes had shown elevated intraocular pressure readings preoperatively. The corpora amylacea count was correlated with histomorphometric changes of the intra- and parapapillary region. The corpora amylacea count of the retinal ganglion cells decreased significantly with increased histological ratio of cup to disc, decreased retinal nerve fiber layer thickness, and increased optic cup depth. There was no significant correlation between the corpora amylacea count of the bipolar cells and each histomorphometric datum. These results suggest that the corpora amylacea of the retinal ganglion cells decrease in number with advancing histological changes of secondary glaucoma.

Adult↗

PubMed1998

Changes in conceptions of meaning, effects and treatment of amblyopia. A phenomenographic analysis of interview data from parents of amblyopic children.

The research reported is an experimental study on the effects of intensified education of parents of children with amblyopia on their understanding of the nature of the defect, its origins and treatment. Parents in the control group were exposed to the ordinary information provided at two departments of paediatric ophthalmology, whereas parents in the experimental group, attending the same clinics, were asked to read a booklet aiming at enhancing their understanding of amblyopia and its treatment. Experimental as well as control subjects were thereafter interviewed about their understanding of the meaning of amblyopia and amblyopia-related phenomena. Data were generated in single subject, semi-structured, in-depth interviews which were taped and transcribed in extenso. The interviews were analyzed according to the phenomenographic approach: i.e. the outcome is a description of the various conceptions that emerged in the interviews. In almost all cases the categories of meaning could be hierarchically ordered with regard to the level of understanding implied. Parallel to the interviews the subjects had also filled out a questionnaire assessing general and specific attitudes towards disease and treatment (the Health Belief Model, HBM). The results reveal a superior understanding among parents in the experimental group. The experimental group had also changed attitudes towards disease and treatment in a direction that would favour compliance, more than could be observed in the control group. The outcome is discussed in terms of the role of understanding for a compliant behaviour. It is also emphasised that health care personnel would profit from being aware of the nature of common misconceptions of diseases and their treatment, in the sense that they would be better prepared for entering instructional dialogues with patients or, as in this case, other persons responsible for the management of prescriptions provided.

Adult↗

PubMed1998

Excimer laser phototherapeutic keratectomy for recurrent pterygium.

PURPOSE: To analyze the results of excimer laser phototherapeutic keratectomy (PTK) combined with simple excision in recurrent pterygium to minimize the recurrence rate and obtain a smooth corneal surface. SETTING: Veni Vidi Eye Health Centre, Istanbul, Turkey. METHODS: Combined pterygium excision and excimer laser PTK was performed in 22 eyes with recurrent pterygium (22 patients). Both spot and scan modes of the Meditec MEL 60 excimer laser were used to produce a wide ablation layer (depth 40 to 80 microns). RESULTS: During the mean follow-up of 16.5 months (range 6 to 27 months), visual acuity, refraction, slitlamp, and corneal topography examinations were recorded. Pterygium recurred in only 1 eye (4.5%). Postoperative visual acuity improved in 15 eyes (68.2%). Keratometric readings were not accurately measured preoperatively because of corneal surface irregularities but could be easily taken after the surgery. Corneal astigmatism ranged from 0 to 2.00 diopters (D) (mean 1.23 D). Three months after surgery, no haze persisted in any eye. No significant intraoperative or postoperative complication was detected. CONCLUSIONS: Excimer laser PTK appears to simplify pterygium surgery because a superficial keratectomy is sufficient to remove pterygium. The excimer laser can be used to ablate the visible residual tissues and smooth the corneal surface, resulting in good postoperative refraction and visual acuity. Consequently, this procedure seems to be effective and safe.

Adult↗

PubMed2004

Are size illusions in simple line drawings affected by shading?

In a number of simple line drawings, such as the Müller-Lyer or Judd figures, we can experience strong distortions of perceived space-geometric illusions. One way of explaining these effects is based on the perspective information that can be read from the line drawings. For instance, the 'inappropriate constancy scaling' theory advocates that the inferred three-dimensional structure of the pictured object is used by the perceptual system to adjust the size of line-drawing components. Such a theory would predict that additional depth cues, for instance shading added to line drawings, should affect these illusions because they influence the three-dimensional appearance. We present here systematic measurements of the magnitude of length misjudgments in horizontal Müller-Lyer and Judd figures for three configurations: (i) pure line drawings, and with shading attached to (ii) the top, and (iii) the bottom of the figures. The latter two configurations are unambiguously interpreted as 'folded' structures with a horizontal edge behind the image plane or protruding from it, respectively. While we could not find any effect of shading in our experimental data, we did observe a length misjudgment in Judd figures that corresponds precisely to the asymmetry that can be observed in the Müller-Lyer illusion for inward and outward fins. This pattern of results is not consistent with notions of inappropriate constancy scaling but is fully coherent with the view that neural filtering mechanisms, which are affecting the perceived position of line intersections, are responsible for this type of geometrical illusions.

Cues↗

PubMed2002

Height and its relationship to refraction and biometry parameters in Singapore Chinese children.

PURPOSE: To examine the association between the anthropometric measurements of height, weight, body mass index (BMI) and refraction and other ocular parameters in Singapore Chinese children. METHODS: In a cross-sectional study of 1449 Chinese schoolchildren, aged 7 to 9 years, from three Singapore schools, height and weight were measured according to standard protocol, and BMI was calculated. Refractive error and corneal curvature measures were determined by autorefraction in eyes under cycloplegia. Axial length, vitreous chamber depth, lens thickness, and anterior chamber depth were measured using A-scan biometry ultrasonography. RESULTS: In comparison with the children with height in the first quartile for a given age and gender, the eyeball length in children in the fourth quartile was 0.46 mm longer, the vitreous chamber depth 0.46 mm deeper, the corneal radius of curvature 0.10 mm greater (i.e., flatter), refraction more negative by 0.47 D (-0.76 D versus -0.29 D), and axial length-to-corneal curvature radius (AL-CR) ratio higher, after analyses controlling for age, gender, parental myopia, reading, school, and weight. The associations of height with refractive error and AL-CR ratio were significant in girls but not in boys. Heavier and more obese children had refractions that were more hyperopic (P = 0.01, P = 0.08), after analyses controlling for age, gender, parental myopia, reading, and school (height was also controlled for if weight was evaluated). This association was present in boys but not in girls. CONCLUSIONS: Controlling for age, gender, parental myopia, reading, school, and weight showed that taller Singapore Chinese children had eyes with longer axial lengths, deeper vitreous chambers, flatter corneas, and refractions that tended toward myopia. In multivariate analysis, eyes in children who were heavier or who had a higher BMI tended to have refractions that were more hyperopic, and eyes in heavier children had shorter vitreous chambers. Differences between the present results and a recent report in Singapore adults suggest either a cohort effect or a potential influence of systemic endocrine or metabolic factors during childhood on refractive development.

Biometry↗

PubMed1990

[Computerized electroencephalographic monitoring in anesthesia].

The computerized electroencephalogram monitor provides a simple interpretation of the standard EEG trend. In the operating room, this compact EEG monitor is convenient and the trend is easy to read for a non-specialist user. EEG monitoring is especially indicated in carotid endarterectomy for the detection of ischemic event during surgery. The use of this monitor should be recommended for high risk patients (cardiac surgery, cerebral aneurysm surgery, controlled hypotension) to determine the adequate depth of anesthesia and to perform a stress-free anesthesia when the anesthetic drug is given by titration according to the decrease in the awakening electrical cerebral activity.

Anesthesiology↗

PubMed2004

Inter- and intra-study reproducibility of contrast echocardiography for assessment of interventricular septal wall perfusion rate in humans.

AIMS: To assess inter- and intra-study reproducibility of myocardial contrast echocardiography (MCE) imaging for quantitative measurement of myocardial perfusion rate in humans in ambulatory setting. METHODS AND RESULTS: In 20 subjects, we performed 2 MCE tests 20-40 min apart on the same day under the same standardized protocol, and evaluated single-reader between-study and between-reading reproducibility of assessment of indicators of myocardial perfusion rate, such as the slope of video-intensity change k, and the factors A (peak video-intensity) and B (background video-intensity after bubble destruction) and the product k X A. The region of interest was placed at the mid-posterior interventricular septal wall visualized in apical 4-chamber view. In a sub-analysis, we evaluated indicators of myocardial perfusion rate comparing subjects with normal vs. those with subnormal ejection fraction (EF). Inter-study reproducibility of assessment of k was relatively low (intraclass correlation coefficient = 0.36), whereas intra-study reproducibility was fair (intraclass correlation coefficient = 0.61). The parameters k X A and B showed higher reproducibility than the k (inter- and intra-study intraclass correlation coefficients 0.64 and 0.75, 0.74 and 0.91, respectively). For reference, reproducibility data of the depth of the region of interest, of EF and CO were excellent. k and k X A were lower in subjects with low vs. those with normal EF. Only k and k X A were lower in subjects with subnormal than in those with normal EF. CONCLUSIONS: The MCE-derived indicator of myocardial perfusion rate k X A showed fairly good between-study and between-reading reproducibility.

Aged↗

PubMed1996

How nurse teachers keep up-to-date: their methods and practices.

A total of 316 nurse teachers completed a self-administered questionnaire in an investigation of the methods and practices they use to keep up-to-date. The study was in two stages. In the first stage, 240 respondents were asked to rate 13 activities as indispensable, useful or of minimal value for updating. Responses were not found to depend significantly on qualifications or years of experience (P < 0.05). Reading journals was most frequently rated as indispensable and in a separate question most indispensable of all. In the second stage, studying for a degree or diploma was added, giving a total of 14 activities. These were rated for four different purposes: topping up; restoring fluency; increasing depth; or adding to range of knowledge/skills. Most discrimination was observed for the category restoring fluency. The time nurse teachers spend on updating, the updating activities they spend most time on and set time aside for, and how they keep clinical skills up-to-date, were also assessed.

Education, Nursing, Continuing↗

PubMed2002

The current status of curettage and electrodesiccation.

Curettage and electrodesiccation (CE) is a technique widely used in the destruction of benign and selected malignant cutaneous neoplasms. CE is used mainly by dermatologists and family practice physicians, whereas plastic surgeons and other surgeons excise most benign and malignant lesions. The use of CE for the treatment of skin cancer has been widely extolled and also fervently criticized. Some practitioners treat most non-melanoma skin cancers (NMSC) with CE, and others have called for abandoning the technique in the treatment of such lesions. A thorough review of the literature reveals that CE has both virtues and flaws. In taking a rational approach to the treatment of benign and malignant cutaneous lesions it is essential to learn the basis for CE, the likely cure rates for given lesions, the proper technique, and the expected level of cosmesis. As the surgical treatment of skin cancer has become firmly entrenched in the field of dermatology, it is valuable to examine this technique in depth and to come to some thoughtful conclusions about its use for patients with skin cancer and assorted benign skin lesions. Last year a remarkably complete and exhaustive favorable review of curettage, electrosurgery, and skin cancer was published by Sheridan and Dawber. This article is a must read for anyone performing curettage; however, the author is writing with a slightly different perspective, that of a dermatologic surgeon. Although the author believes that CE has value and he uses this technique frequently, he disagrees with some of the truisms expressed in the literature about CE and attempts to define carefully what he believes are the strengths and limitations of this technique.

Curettage↗

PubMedDate not supplied

Calorimetric determination of the cavity-gas calibration factor Ngas.

In the recently published AAPM protocol for the dosimetry of high-energy photons and electrons, the response of an ionization chamber is defined as the dose to the gas in the chamber per unit electrometer reading, Ngas. Using a graphite calorimeter, Ngas has been determined for a Farmer-type ionization chamber using 4- and 25-MV x rays. The procedure was to measure the dose to graphite using the calorimeter, and then obtain the response of the chamber at the same depth in a graphite phantom. Equation (9) of the AAPM protocol was then used to calculate Ngas. The values of Ngas determined with the calorimeter are within 1% of Ngas calculated according to the AAPM protocol, using the 60Co exposure-calibration factor.

Calorimetry↗