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PubMed1979

Multidetector endodosimetry probe with silicon-pn-junction-diodes for in-vivo-dosimetry.

In-vivo-dosimetry is necessary to prevent overdosage during radiation treatment techniques of great risk. New special dosemeter probes with up to five Si-pn-junction-diodes in a silicone tube were developed and tested for endodosimetry. They show high efficiency and good linearity of response, without dose-rate dependence. The steep increase of the sensitivity for low energies causes a phantom depth dependence of response. A low temperature dependence but a large anisotropy of response is found for the tested diodes. These multidetector probes proved to be sufficient for direct reading endodosimetric control of dose and dose-distribution during radiotherapy.

Brachytherapy↗
PubMed2006

The impact of meaning and dimensionality on copying accuracy in individuals with autism.

Weak Central Coherence (Frith, 1989) predicts that, in autism, perceptual processing is relatively unaffected by conceptual analysis. Enhanced Perceptual Functioning (Mottron & Burack, 2001) predicts that the perceptual processing of those with autism is less influenced by conceptual analysis only when higher-level processing is detrimental to task performance. This research tested these theories using a copying task where one conceptual aspect enhances accuracy (meaningfulness) and another hinders it (three-dimensionality). Children and adolescents with and without autism copied meaningful and non-meaningful two-dimensional and three-dimensional line drawings. Drawing accuracy and strategy (global/local) were assessed. Participants with autism were less affected by dimensionality but not meaningfulness, apparently supporting EPF. Effects of dimensionality did not relate to drawing strategy, also contrary to WCC.

Adolescent↗
PubMed2000

Mind-body dualism and the biopsychosocial model of pain: what did Descartes really say?

In the last two decades there have been many critics of western biomedicine's poor integration of social and psychological factors in questions of human health. Such critiques frequently begin with a rejection of Descartes' mind-body dualism, viewing this as the decisive philosophical moment, radically separating the two realms in both theory and practice. It is argued here, however, that many such readings of Descartes have been selective and misleading. Contrary to the assumptions of many recent authors, Descartes' dualism does attempt to explain the union of psyche and soma - with more depth than is often appreciated. Pain plays a key role in Cartesian as well as contemporary thinking about the problem of dualism. Theories of the psychological origins of pain symptoms persisted throughout the history of modern medicine and were not necessarily discouraged by Cartesian mental philosophy. Moreover, the recently developed biopsychosocial model of pain may have more in common with Cartesian dualism than it purports to have. This article presents a rereading of Descartes' mental philosophy and his views on pain. The intention is not to defend his theories, but to re-evaluate them and to ask in what respect contemporary theories represent any significant advance in philosophical terms.

Global Health↗
PubMed2004

Dose rate and SDD dependence of commercially available diode detectors.

The dose-rate dependence of commercially available diode detectors was measured under both high instantaneous dose-rate (pulsed) and low dose rate (continuous, Co-60) radiation. The dose-rate dependence was measured in an acrylic miniphantom at a 5-cm depth in a 10 x 10 cm2 collimator setting, by varying source-to-detector distance (SDD) between at least 80 and 200 cm. The ratio of a normalized diode reading to a normalized ion chamber reading (both at SDD=100 cm) was used to determine diode sensitivity ratio for pulsed and continuous radiation at different SDD. The inverse of the diode sensitivity ratio is defined as the SDD correction factor (SDD CF). The diode sensitivity ratio increased with increasing instantaneous dose rate (or decreasing SDD). The ratio of diode sensitivity, normalized to 4000 cGy/s, varied between 0.988 (1490 cGy/s)-1.023 (38,900 cGy/s) for unirradiated n-type Isorad Gold, 0.981 (1460 cGy/s)-1.026 (39,060 cGy/s) for unirradiated QED Red (n type), 0.972 (1490 cGy/s)-1.068 (38,900 cGy/s) for preirradiated Isorad Red (n type), 0.985 (1490 cGy/s)-1.012 (38,990 cGy/s) for n-type Pt-doped Isorad-3 Gold, 0.995 (1450 cGy/s)-1.020 (21,870 cGy/s) for n-type Veridose Green, 0.978 (1450 cGy/s)-1.066 (21,870 cGy/s) for preirradiated Isorad-p Red, 0.994 (1540 cGy/s)-1.028 (17,870 cGy/s) for p-type preirradiated QED, 0.998 (1450 cGy/s)-1.003 (21,870 cGy/s) for the p-type preirradiated Scanditronix EDP20(3G), and 0.998 (1490 cGy/s)-1.015 (38,880 cGy/s) for Scanditronix EDP10(3G) diodes. The p-type diodes do not always show less dose-rate dependence than the n-type diodes. Preirradiation does not always reduce diode dose-rate dependence. A comparison between the SDD dependence measured at the surface of a full scatter phantom and that in a miniphantom was made. Using a direct adjustment of radiation pulse height, we concluded that the SDD dependence of diode sensitivity can be explained by the instantaneous dose-rate dependence if sufficient buildup is provided to eliminate electron contamination. An energy independent empirical formula was proposed to fit the dose-rate dependence of diode sensitivity.

Equipment Failure Analysis↗
PubMedDate not supplied

Development of the Grammar and Phonology Screening (GAPS) test to assess key markers of specific language and literacy difficulties in young children.

BACKGROUND: Despite a large body of evidence regarding reliable indicators of language deficits in young children, there has not been a standardized, quick screen for language impairment. The Grammar and Phonology Screening (GAPS) test was therefore designed as a short, reliable assessment of young children's language abilities. AIMS: GAPS was designed to provide a quick screening test to assess whether pre- and early school entry children have the necessary grammar and pre-reading phonological skills needed for education and social development. This paper reports the theoretical background to the test, the pilot study and reliability, and the standardization. METHODS: This 10-min test comprises 11 test sentences and eight test nonsense words for direct imitation and is designed to highlight significant markers of language impairment and reading difficulties. To standardize the GAPS, 668 children aged 3.4-6.6 were tested across the UK, taking into account population distribution and socio-economic status. The test was carried out by a range of health and education professionals as well as by students and carers using only simple, written instructions. RESULTS: GAPS is effective in detecting a range of children in need of further in-depth assessment or monitoring for language difficulties. The results concur with those from much larger epidemiological studies using lengthy testing procedures. CONCLUSIONS: The GAPS test (1) provides a successful screening tool; (2) is designed to be administered by professionals and non-professionals alike; and (3) facilitates identification of language impairment or at-risk factors of reading impairment in the early educational years. Thus, the test affords a first step in a process of assessment and targeted intervention to enable children to reach their potential.

Age Distribution↗
PubMed2025

The chromosome-level genome assembly and annotation of the silver-lipped pearl oyster, Pinctada maxima.

The silver-lipped pearl oyster (Pinctada maxima) is a valuable tropical aquaculture species, playing a crucial economic role in the global pearl industry. However, the lack of genomic reference limits our in-depth understanding of this species in genome-based breeding, conservation, evolution and adaptation. Here, annotated chromosome-level reference genome for P. maxima was generated by integrating PacBio long-read sequencing, Illumina short-read sequencing, and Hi-C sequencing data. The total genome size is 1,264.93&#x2009;Mb, with contig N50 and scaffold N50 of 649&#x2009;kb and 89.19&#x2009;Mb, respectively. The majority (97.94%) of the assembled genome was anchored to the 14 chromosomes by Hi-C analysis. The relatively high genome completeness was observed, with 97.38% (metazoa_odb10 database) and 95.26% (mollusca_odb10 database) in BUSCO analysis. Genome annotation revealed approximately 65.46% of the repeat sequences and 26,315 protein-coding genes. Comparative genome analysis revealed 28 expanded and 48 contracted families (p&#x2009;<&#x2009;0.05) in P. maxima, with 3.2% of genes (894) being species-specific. This chromosome-level genome serves as an essential resource for research in evolutionary genomics, phylogenetics, and biomineralization.

Animals↗
PubMedDate not supplied

Dose errors due to charge storage in electron irradiated plastic phantoms.

Commercial plastics used for radiation dosimetry are good electrical insulators . Used in electron beams, these insulators store charge and produce internal electric fields large enough to measurably alter the electron dose distribution in the plastic. The reading per monitor unit from a cylindrical ion chamber imbedded in a polymethylmethacrylate (PMMA) or polystyrene phantom will increase with accumulated electron dose, the increase being detectable after about 20 Gy of 6-MeV electrons. The magnitude of the effect also depends on the type of the plastic, the thickness of the plastic, the wall thickness of the detector, the diameter and depth of the hole in the plastic, the energy of the electron beam, and the dose rate used. Effects of charge buildup have been documented elsewhere for very low energy electrons at extremely high doses and dose rates. Here we draw attention to the charging effects in plastics at the dose levels encountered in therapy dosimetry where ion chamber or other dosimeter readings may easily increase by 5% to 10% and where a phantom, once charged, will also affect subsequent readings taken in 60Co beams and high-energy electron and x-ray beams for periods of several days to many months. It is recommended that conducting plastic phantoms replace PMMA and polystyrene phantoms in radiation dosimetry.

Electrons↗
PubMed1990

Visual cues in the interpretation of medical images.

The use of the computer in imaging has provided great versatility for the display of medical image information. In order to be useful in a medical sense, the display must be perceptually acceptable to the human observer, who must be able to extract the relevant diagnostic information from the image. Diagnostic information is defined by the imaging task, and the concept of task-dependent image quality is, therefore, very important. Visualization and estimation tasks may require different visual cues for their performance. Visualization tasks require strong boundary cues, whereas intensity estimation tasks require texture cues. Both tasks can be aided by appropriate image displays. Color can be helpful in estimation tasks, and three-dimensional display can aid visualization tasks. No matter what the task or the image, as long as an observer is needed to read out the information, performance is the final arbiter of the goodness of the image.

Color Perception↗
PubMed1995

[Functional results in bilateral implantation of a foldable refractive multifocal posterior chamber lens].

BACKGROUND: Clinical studies of multifocal intraocular lenses have primarily investigated functional results unilaterally. In the following study we have examined functional results after bilateral implantation of a refractive multifocal intraocular lens, which had already shown good results with unilateral testing situations. MATERIALS AND METHODS: After implantation of 36 foldable refractive multifocal posterior-chamber lenses in 25 patients we compared two patient groups concerning functional results: 11 patients with bilateral implantation against 14 patients with unilateral implantation of this lens type. We tested binocular function of distance visual acuity, near visual acuity, depth of focus, stereopsis, glare visual acuity and contrast sensitivity. RESULTS: The patients with bilateral implantation had a significantly better distance visual acuity, depth of focus and stereopsis tested according to Lang. Stereopsis tested according to Randot or Titmus and near visual acuity were not significantly but in trend better in patients with bilateral implantation. There were no differences in glare visual acuity or contrast sensitivity. The patients with bilateral implantation used more seldom glasses for reading, but they did not describe more disturbing optical phenomenons. CONCLUSIONS: Having a satisfied patient with a multifocal lens in one eye the implantation of the same type of lens into the second eye will bring further functional advantage to the patient.

Aged↗
PubMed2001

Situation models and aging.

Younger and older adults were tested for their ability to process and retrieve information from texts. The authors focused on the construction and retrieval of situation models relative to other types of text representations. The results showed that during memory retrieval, younger adults showed superior memory for surface form and textbase knowledge (what the text was), whereas older adults had equivalent or superior memory for situation model information (what the text was about). The results also showed that during reading, older and younger adults were similar in their sensitivity to various aspects of the texts. Overall, these findings suggest that although there are age-related declines in the processing and memory for text-based information, for higher level representations, these abilities appear to be preserved. Several possibilities for why this is the case are discussed, including an in-depth consideration of one possibility that involves W. Kintsch's (1988) construction-integration model.

Age Factors↗
PubMed1982

Lateral asymmetry: hard or simple-minded?

A letter or a three-dimensional shape was presented in the center of the visual field. Following the off-set of this stimulus either a comparison letter or a three-dimensional shape was flashed briefly in either the right or left visual field. The subject's task was to respond SAME, or DIFFERENT. The stimuli could be in the same plane, rotated in two dimensions (letters) or in three dimensions (three-dimensional shapes). The left visual field presentations (right hemisphere) of same-pair matches for letters only produced faster reaction times and fewer errors. In all other conditions reaction time measures showed no hemisphere effects. By contrast, error score data indicated that the left hemisphere was overwhelmingly more accurate.

Adolescent↗
PubMed2002

A TLD-based few-channel spectrometer for mixed photon, electron, and ion fields with high fluence rates.

A few-channel spectrometer for mixed photon, electron and ion radiation fields has been developed. It consists of a front layer of an etched-track detector foil for detecting protons and ions, a stack of PMMA with thermoluminescent detectors at different depths for gaining spectral information about electrons, and a stack of metallic filters with increasing cut-off photon energies, interspersed with thermoluminescent detectors for gaining spectral information about photons. From the reading of the TL detectors the spectral fluence of the electrons (400 keV to 9 MeV) and photons (20 keV to 2 MeV) can be determined by an unfolding procedure. The spectrometer can be used in pulsed radiation fields with extremely high momentary values of the fluence rate. Design and calibration of the spectrometer are described.

Electrons↗
PubMed2006

Corneal ectasia after laser in situ keratomileusis in patients without apparent preoperative risk factors.

PURPOSE: To evaluate patients who developed ectasia with no apparent preoperative risk factors. METHODS: Potential cases of patients who developed ectasia without apparent risk factors were identified by contacting participants in the Kera-Net (n = 580), ASCRS-Net (n = 450), and ISRS/AAO ISRS-Net (n = 525) internet bulletin boards from April to October 2003. Cases were included if ectasia developed after laser in situ keratomileusis in the absence of apparent preoperative risk factors. Reported cases were excluded for the following reasons: (1) calculated residual stromal bed less than 250 microm, (2) preoperative central pachymetry less than 500 microm, (3) any keratometry reading greater than 47.2 diopters (D), (4) a calculated inferior-superior value greater than 1.4, (5) more than 2 retreatments, (6) attempted initial correction greater than -12.00 D, (7) an Orbscan II "posterior float" (if obtained) greater than 50 microm, and (8) surgical/flap complications. RESULTS: A total of 27 eyes of 25 patients were submitted for consideration. Eight eyes (8 patients) met our inclusion criteria. Mean age was 27.7 years (range, 18-41 years). Preoperative manifest refraction spherical equivalent was -4.61 D (range, -2.00 to -8.00 D); steepest keratometric reading was 43.86 D (range, 42.50-46.40 D); keratometric astigmatism was 0.93 D (range, 0.25-1.90 D); and preoperative central pachymetry was 537 microm (range, 505-560 microm). The mean calculated ablation depth was 82.8 microm (range, 21-125.4 microm), and mean calculated residual stromal bed was 299.5 microm (range, 254-373 microm). Mean time to recognition of ectasia onset was 14.2 months (range, 3-27 months) postoperatively. At the time of ectasia diagnosis, the mean manifest refraction spherical equivalent was -1.23 D (range, +0.125 to -3.00) with a mean of 2.72 D (range, 0.75-4.00 D) of astigmatism. CONCLUSIONS: Ectasia can occur after an otherwise uncomplicated laser in situ keratomileusis procedure, even in the absence of apparent preoperative risk factors.

Adolescent↗
PubMed1995

Intrasulcular laser Doppler readings before and after root planing.

A reproducible and sensitive laser Doppler periodontal probe has recently been developed for intrasulcular measurement of gingival blood flow. The specific aims of this investigation were to determine the relation between intrasulcular laser Doppler readings (LDR) and traditional diagnostic criteria as well as to evaluate the response to root planning in terms of LDR and traditional criteria. LDR and clinical measurements (bleeding on probing (BOP), probing depth (PD) and clinical attachment loss (CAL) were obtained from 2 healthy and 2 diseased sites in 30 systemically healthy adult volunteers with localized moderate to advanced periodontitis. All 30 subjects were re-examined 1 month following root planing while 10 subjects were re-examined at approximately 1 year after treatment. Subject-adjusted correlations between pretreatment LDR and PD as well as LDR and CAL were 0.74 and 0.71, respectively. 1 month following root planing, the diseased sites had undergone a significant reduction in LDR and PD with an accompanying gain in CAL. Prior to treatment, 95 of 120 sites (79%) agreed on an ordinal classification (high, low) for LDR and BOP. Mantel-Haenszel common odds ratios for agreement between LDR and BOP were 9.6 pre-treatment and 4.3 one month after treatment. A slight rebound of all measurements was noted in a group of 10 subjects followed for 1 year. It was concluded that the laser Doppler periodontal probe is an unbiased non-invasive method of monitoring the response to periodontal therapy.

Adult↗
PubMed1996

Benefits of ambulatory blood pressure monitoring in the design of antihypertensive drug trials.

REVIEW IN DEPTH: Ambulatory blood pressure monitoring (ABPM) offers substantial advantages over conventional clinic measurement in the assessment of antihypertensive agents. There is a greater reproducibility of an average blood pressure taken from multiple readings,s and in the setting of a clinical trial this translates into increased precision of the assessment of mean antihypertensive effect. The temporal profile of blood pressure and the antihypertensive effect of an agent can be studied directly, and times of the day of particular clinical importance, such as the end of the dosing period and the early morning period, can be studied more easily than for conventional blood pressure measurement. ABPM reduces the size of any placebo effect on blood pressure to very low values, and it can be used to exclude white-coat hypertensives from clinical trials, thereby reducing the noise in a clinical trial. The role of ABPM in drug evaluation looks set to increase further with new developments in blood pressure measurement technology.

Journal Article↗
PubMed1989

[Esophageal acid exposure in a single number: the area under the pH curve].

Current interpretation of pH-metering tracings takes into account several variables which indirectly reflect how many times and for how long time pH falls below a threshold value and how efficient is acid clearance. In this investigation we have tested the hypothesis that area under pH curve summarizes all the former values in one single figure. We have compared the four classical pH-metering variables (percentage of time under pH 4, number of GER episodes, number of those lasting more than 5 minutes and duration of the longer episode) and the area under curve between a group of refluxing children (n = 50) and a control group (n = 20). A value of 4% time under pH 4 was selected as "gold standard" for separation of both groups. We have figured out sensitivity, specificity and accuracy for all values of each parameter and, by means of ROC (Receiver Operating Characteristic) method, we have determined their performance and the optimum threshold value. Our results demonstrate that area under curve is at least as performant as percentage of time below pH 4, and probably better because it reflects, in addition, the depth of pH falls and the clearance. Taking into consideration that its measurement can be done automatically, we suggest that it should be included in the currently available software for computerized pH reading.

Adolescent↗
PubMed1994

Phylogenetic depth of S10 and spc operons: cloning and sequencing of a ribosomal protein gene cluster from the extremely thermophilic bacterium Thermotoga maritima.

A segment of Thermotoga maritima DNA spanning 6,613 bp downstream from the gene tuf for elongation factor Tu was sequenced by use of a chromosome walking strategy. The sequenced region comprised a string of 14 tightly linked open reading frames (ORFs) starting 50 bp downstream from tuf. The first 11 ORFs were identified as homologs of ribosomal protein genes rps10, rpl3, rpl4, rpl23, rpl2, rps19, rpl22, rps3, rpl16, rpl29, and rps17 (which in Escherichia coli constitute the S10 operon, in that order); the last three ORFs were homologous to genes rpl14, rpl24, and rpl5 (which in E. coli constitute the three promoter-proximal genes of the spectinomycin operon). The 14-gene string was preceded by putative -35 and -10 promoter sequences situated 5' to gene rps10, within the 50-bp spacing between genes tuf and rps10; the same region exhibited a potential transcription termination signal for the upstream gene cluster (having tuf as the last gene) but displayed also the potential for formation of a hairpin loop hindering the terminator; this suggests that transcription of rps10 and downstream genes may start farther upstream. The similar organization of the sequenced rp genes in the deepest-branching bacterial phyla (T. maritima) and among Archaea has been interpreted as indicating that the S10-spc gene arrangement existed in the (last) common ancestor. The phylogenetic depth of the Thermotoga lineage was probed by use of r proteins as marker molecules: in all except one case (S3), Proteobacteria or the gram-positive bacteria, and not the genus Thermotoga, were the deepest-branching lineage; in only two cases, however, was the inferred branching order substantiated by bootstrap analysis.

Amino Acid Sequence↗