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At least 73 records · Page 4Linked to original sources

PubMed1992

1991 Federal Nursing Service Award recipient. The effect of increased atmospheric pressure on glucose reagent strip accuracy.

Hyperbaric oxygen (HBO) is currently being used throughout the world as an adjunctive therapy for non-healing diabetic wounds. Anecdotal accounts of diabetic patients experiencing hypoglycemic reactions with HBO necessitated glucose testing by fingerstick during treatment dives to 2.4 atmospheres absolute. This study looked at four glucose testing methods and the accuracy of their readings using high and low control solutions at both sea level and at depth. A one-way analysis of variance showed significant differences with all of the high and 75% of the low control solutions when comparing sea level readings to depth readings. The significance varied between reaction rate and end point reading methods, with the reaction rate technology performing better.

Air Pressure↗

PubMed1999

Conjoint dissociations reveal involuntary "perceptual" priming from generating at study.

Incidental perceptual memory tests reveal priming when words are generated orally from a semantic cue at study, and this priming could reflect contamination by voluntary retrieval. We tested this hypothesis using a generate condition and two read conditions that differed in depth of processing (read-phonemic vs read-semantic). An intentional word-stem completion test showed an advantage for the read-semantic over the generate condition and an advantage for the generate over the read-phonemic condition, and completion times were longer than in a control test, prior to which there was no study phase. An incidental word-stem completion test showed equivalent priming for the read-semantic and read-phonemic study conditions, despite considerable power, and completion times were no longer than control, indicating that retrieval was involuntary, and insensitive to prior conceptual processing. The generate condition produced less priming than the read conditions, but significant priming nonetheless. The results show that priming from generating can be involuntary and suggest that lexical processes are responsible. They are also the first results conjointly showing a crossed double dissociation, a single dissociation, and a parallel effect across memory tests with identical physical retrieval cues.

Cues↗

PubMed2005

Early computational processing in binocular vision and depth perception.

Stereoscopic depth perception is a fascinating ability in its own right and also a useful model of perception. In recent years, considerable progress has been made in understanding the early cortical circuitry underlying this ability. Inputs from left and right eyes are first combined in primary visual cortex (V1), where many cells are tuned for binocular disparity. Although the observation of disparity tuning in V1, combined with psychophysical evidence that stereopsis must occur early in visual processing, led to initial suggestions that V1 was the neural correlate of stereoscopic depth perception, more recent work indicates that this must occur in higher visual areas. The firing of cells in V1 appears to depend relatively simply on the visual stimuli within local receptive fields in each retina, whereas the perception of depth reflects global properties of the stimulus. However, V1 neurons appear to be specialized in a number of respects to encode ecologically relevant binocular disparities. This suggests that they carry out essential pre-processing underlying stereoscopic depth perception in higher areas. This article reviews recent progress in developing accurate models of the computations carried out by these neurons. We seem close to achieving a mathematical description of the initial stages of the brain's stereo algorithm. This is important in itself--for instance, it may enable improved stereopsis in computer vision--and paves the way for a full understanding of how depth perception arises.

Animals↗

PubMed2001

River loggers--a new tool to monitor riverine suspended particle fluxes.

The Australian Institute of Marine Science (AIMS) has developed an in situ digital turbidity logger (AIMS River Logger) to record time series of fine suspended sediment concentrations in North Queensland rivers. The loggers use dual LED transmissometers (15 and 85 mm pathlength) to measure in situ turbidity associated with the range of suspended sediment concentrations (0-5 g L-1) encountered in regional rivers. A system of wiper brushes clean the optical surfaces prior to instrument readings. Overlying water depth and temperature are concurrently recorded. Internal batteries provide sufficient power for unattended deployments of 6+ months with readings taken at 30 minute intervals. Records of suspended sediment concentrations in the lower Tully River over three wet seasons (1996, 1997, 2000) are shown in relation to concurrent river discharge. Peaks in suspended sediment concentration coincide with discharge events. During each event, peak sediment concentrations typically occur during the rising stage of the hydrograph, then decline rapidly prior to significant falls in water level. Derived suspended loads during discharge events are generally proportional to the size of the event, though higher responses are recorded during the initial flood event of each wet season.

Environmental Monitoring↗

PubMed2001

Monovision: a review of the scientific literature.

We reviewed the scientific literature on monovision to compare the visual performance of monovision patients with that of others wearing more traditional prescriptions. We found that visual performance of monovision patients was comparable to that of control patients wearing a balanced binocular correction, provided that reading adds were not greater than about +2.5 D, that illumination was photopic, and that stimuli were presented at supra-threshold levels. Under these conditions, monovision patients were satisfied with their perceptual experience and performed within 2 to 6% of balanced binocular control patients on a range of occupational tasks. It is noteworthy that monovision patients had relatively more difficulty with acuity-based tasks than with tasks demanding good depth perception. With reading adds over +2.5 D, at low levels of illumination, or with near-threshold level stimuli, visual performance of monovision patients was reduced compared with controls. Subjectively, under low levels of illumination, monovision patients experienced problems with glare and halos around point sources of light.

Contact Lenses↗

PubMed1983

[Characteristics of thermoluminescent dosimeters for the brehmsstrahlung and electron radiation of the betatron B5M-25].

The authors present the results of the experimental and theoretical determination of coefficients of the transition from readings of thermoluminescent detectors on the basis of alumophosphate glass with manganese to an absorbed dose in the water, and the correlation between the detector readings and the depth in the phantom for betatron inhibitory and electron radiations. Comparative measurements of absorbed doses have been done with the help of a ferrosulphate system and 2 dosimeters with ionization chambers (VA-J-18 and Rado-con-III). It has been shown that in case of inhibitory radiation, the readings of thermoluminescent detectors show no correlation with changes of the spectral composition of radiation; for electrons with an average energy of the spectrum at 10 and 20 MEV this dependence does not exceed +/- 2% in the depths from 0 up to 90% of the practical running. Experimentally defined coefficients of the transition from detector readings to an absorbed dose in the water give an opportunity to measure absorbed doses with a summary error that does not exceed 10% (for the confidential interval 95%). The measurement data have been confirmed theoretically, and it makes it possible to use small-size autonomous glass detectors in clinical dosimetry including those for the direct measurement of irradiation doses patients receive, to control the results of the dosimetric planning of radiation therapy. Theoretical correlations obtained can be used for the prognosis of behaviour of thermoluminescent detectors in the fields of inhibitory radiation of high energies and arbitrary spectral composition as well as for electron spectra with energies up to 25 MEV.

Cobalt Radioisotopes↗

PubMed1991

The identification of periodontal attachment loss from clinical measurements.

Clinical readings of pocket depth and loss of periodontal attachment were recorded on the approximal sites of 21 teeth scheduled for extraction. Corresponding laboratory measurements of pocket depth and loss of periodontal attachment were made on the teeth after extraction. Clinical measurements were within 1mm of their corresponding laboratory values on 95% of occasions. Clinical readings of loss of periodontal attachment of 0 or 1mm showed poor agreement with corresponding laboratory measurements. It was concluded that the presence of loss of periodontal attachment can only be reliably identified where a clinical reading of 2mm or greater is recorded.

Adult↗

PubMed2006

Intrapatient reproducibility of the BISxp monitor.

BACKGROUND: The Bispectral Index (BIS) reportedly reflects anesthetic depth. It is recommended that anesthetic agents should be titrated to maintain the BIS between 40 and 60 arbitrary BIS units during anesthesia. For anesthesia providers to follow this recommendation, the monitor should be predictably affected by different anesthetic agents and have good interpatient and intrapatient reproducibility. The authors hypothesized that when two BISxp devices (Aspect Medical Systems, Newton, MA) are placed concurrently on the same patient, their readings are concordant throughout the anesthetic period. METHODS: Simultaneous BIS recordings from two BISxp monitors were obtained during anesthesia at 5-s intervals from 12 participants. RESULTS: In total 22,860 concurrent paired BIS readings were obtained. For 10.7% of the time, there were sustained periods of 30 s or greater where the readings suggested a different depth of anesthesia. For 6% of the time, there were sustained periods of 30 s or greater where the readings differed by 10 or more arbitrary BIS units. The regression coefficient (R) for the two devices was 0.65 (range, 0.35-0.92). There was zero bias between the devices, and the 95% limits of agreement ranged between -18 and +17. CONCLUSION: A conflicting anesthetic management was suggested by the simultaneous BIS readings 10.7% of the time. These results suggest that BISxp does not always provide a reproducible single number. Anesthesia providers should not rely exclusively on the BIS reading when assessing depth of anesthesia.

Adult↗

PubMedDate not supplied

Utilization of laser fluorescence to monitor caries lesions development in primary teeth.

PURPOSE: The objective of this study was to analyze and evaluate laser fluorescence (LF) performance in monitoring and quantifying smooth-surface incipient caries lesions in primary teeth. METHODS: Artificial caries lesions were produced in 2 delimited windows on the buccal surface of 24 primary incisors using a pH-cycling procedure. LF (DIAGNOdent) readings were collected on the windows on each tooth surface before (sound enamel) and after (artificial caries lesions) the demineralization process. The left lesion of each tooth was used for the polarized light microscopy analysis. Statistical tests were performed to observe the performance of the method and correlation between LF readings and caries lesions depth. RESULTS: There was a significant increase in the LF readings after demineralization (P < .0001). The area under receiver operating characteristic curve was 0.956, showing a good result of the method. The best cut off LF value to detect incipient caries was 5, and with this value, sensitivity, specificity, and accuracy was 0.78, 1, and 0.89, respectively. Pearson's correlation coefficient between DIAGNOdent values and caries lesion depth was 0.68. CONCLUSIONS: Although LF was good at detecting artificial caries lesions in primary teeth, the quantification of mineral loss was undesirable.

Dental Caries↗

PubMed2001

Validation of DIAGNOdent for quantification of smooth-surface caries: an in vitro study.

The aims were 1) to validate a laser-based device, KaVo DIAGNOdent, for quantification of caries lesions on smooth surfaces, using histopathologic and microradiographic analyses as the gold standard, and 2) to test inter- and intra-observer agreements. We also investigated the influence on DIAGNOdent readings of the storage medium used for extracted teeth. Two observers measured independently the tooth surfaces of 40 extracted premolars that had been stored in thymol-saturated saline. After subsequent storage in neutral-buffered formalin for 14 days they were re-measured. The teeth were then sectioned for histopathologic and microradiographic analysis. The Spearman rank correlation coefficients between lesion depth and DIAGNOdent readings were 0.78-0.83 and 0.85 for teeth stored in thymol-saturated saline and formalin, respectively. Inter- and intra-observer agreements were 0.94 and 0.95 when the teeth were stored in thymol-saturated saline. The DIAGNOdent reading was almost 1.5 times higher for teeth stored in formalin than for those stored in thymol saline. The Spearman rank correlation coefficient between mineral loss in enamel (deltaZ) and DIAGNOdent readings ranged from 0.64 to 0.68. It was concluded that DIAGNOdent may be helpful for assessing smooth-surface caries, but the cut-off points need to be assessed under clinical conditions. The increase in fluorescence associated with storage of teeth in formalin warrants further investigation.

Analysis of Variance↗

PubMed1998

Depth predictability of stromal pockets in the posterior cornea.

PURPOSE: To evaluate the predictability of the depth of stromal pockets made in the posterior cornea for the excision of anterior or posterior lamellar corneal buttons with a planned thickness. METHODS: Stromal corneal pocket dissections were created in human eye bank eyes by making a peripheral arcuate keratotomy incision at 60, 80, or 95% of central pachymetry and creating a pocket from the bottom of the incision across the cornea. Pocket depth was measured by pachymetry immediately after surgery and by light microscopy. RESULTS: Mean achieved central pocket depth differed by 0.03+/-0.03 mm from the intended depth. Variation in depth across the pocket decreased from 0.07+/-0.02 mm for pockets made at 60% of the intended depth to 0.05+/-0.01 mm for pockets made at 80% depth, and 0.04+/-0.02 mm for pockets made at 95% depth (p < 0.01). Pachymetric and histological measurements of relative pocket depth averaged 64+/-9% and 73+/-7%, respectively, for pockets made at 60% of the intended depth, 82+/-7% and 86+/-3% for pockets made at 80% depth, and 91+/-7% and 92+/-3% for pockets made at 95% depth. The difference between pachymetric and histological relative pocket depth measurements decreased with deeper pocket depth (p < 0.01). CONCLUSIONS: In the posterior cornea, stromal pockets can be created to within 30 microm from the intended depth. Variation in depth throughout the pocket decreases with deeper pocket depth. Pachymetry is a reliable method to check the achieved pocket depth during surgery; the accuracy of pachymetry readings improves with deeper pocket depth.

Corneal Stroma↗

PubMed1987

A QRS detection algorithm.

In this article we present the choices that the designers of any QRS detector must make and explain the constraints we adopted. We outline the signal processing that precedes and the beat analysis that follows QRS detection in our single-channel, arrhythmia-monitoring algorithm and then expound the QRS detection algorithm in detail. Finally, we present the results of a QRS detector performance evaluation and comment on their importance. This article can be read to three depths: the text affords an overview of QRS detection for on-patient, ambulatory arrhythmia analysis; the commented pseudocode documents the logic of our QRS detector; and the pseudocode "footnotes" supply technical detail.

Algorithms↗

PubMed2025

Polygenic variants in DNA repair genes are associated with neurodevelopmental disorders, regression and increased burdens of somatic variants and short tandem repeat expansions.

PURPOSE: Developmental regression, characterized by the loss of acquired milestones, occurs in some individuals with neurodevelopmental disorders (NDDs); yet, its molecular basis remains unclear. Studies suggest that DNA damage repair (DDR) genes, such as FAN1, may protect against neurological dysfunction by modulating the somatic stability of short tandem repeats (STRs). This study explores the contribution of DDR gene variants in NDD cases presenting with regression. METHODS: We analyzed 1087 NDD patients, focusing on those carrying variants in DDR genes and presenting regression. We assessed the sensitivity to DNA damage using mitomycin C on lymphoblastoid cells. Somatic variants and STR expansions were evaluated through high-depth short-read genome sequencing. To further investigate the pathogenetic role of STR expansions, we performed long-read genome sequencing on the most severely affected proband. RESULTS: Probands with regression carried multiple DDR gene variants, several within the Fanconi anemia pathway. Their lymphoblastoid cells showed increased sensitivity to mitomycin C-induced cytotoxicity compared with parental and control samples. Probands with severe phenotypes and regression exhibited an accumulation of somatic variants and STR instability, enriched in neurodevelopmental genes. CONCLUSION: Our findings suggest that polygenic DDR gene variants may contribute to developmental regression in NDDs by promoting the accumulation of somatic variants and STR expansions.

Humans↗

PubMedDate not supplied

The 'three waves' of research in mental health geography: a review and critical commentary.

OBJECTIVE: To consider research conducted in the sub-field of mental health geography, concentrating on work published in English. METHODS: The paper offers an comprehensive, in-depth and critical reading of the relevant literature on mental health geography since the inception of this subfield of inquiry in the early-1970s. RESULTS: The paper identifies three 'waves' of research within work on mental health geography. It describes these 'waves' in detail, interprets certain strengths and weaknesses of the first two 'waves', which are well-established, and provides suggestions about important questions to be addressed in a future third 'wave'. CONCLUSION: Much excellent research has so far been undertaken within mental health geography, but there is scope to increase the relevance of this research through widening the focus of research and by being prepared to connect research more directly to mental health policy and politics.

Ill-Housed Persons↗

PubMed2026

Sperm subpopulations differing in mitochondrial abundance show divergent nuclear allele frequencies.

Mammalian ejaculates contain heterogeneous sperm subpopulations that differ in subcellular architecture and developmental history, despite appearing morphologically uniform. The extent to which this cellular heterogeneity reflects underlying nuclear genomic structure within a sire remains largely unexplored. Mitochondrial architecture in sperm is established during spermatogenesis, with final assembly and organization occurring during spermiogenesis under nuclear genomic control, positioning variation in mitochondrial abundance and organization as a potential phenomic indicator of within-sire allelic segregation. Here, we tested whether sperm subpopulations defined by differing mitochondrial abundance exhibit systematic differences in nuclear allele representation. Boar sperm were resolved into low and high mitochondrial subpopulations using fluorescence-activated cell sorting based on MitoTracker™ Green fluorescence while excluding debris, doublets, and non-viable cells. Epifluorescence microscopy confirmed that high MitoTracker™ Green fluorescence sperm possessed longer mitochondrial sheaths, validating a structural distinction between subpopulations. Whole-genome sequencing of paired mitochondrial subpopulations from three boars was performed, and allelic ratio distortion was evaluated relative to heterozygous baseline populations. Analyses across heterozygous loci genome-wide identified candidate allele frequency shifts between mitochondrial-defined subpopulations, suggesting non-random segregation of alleles within ejaculates. Using a minimum sequencing depth of 30 reads in both sorted fractions, 182 candidate SNPs were identified with evidence of allele-frequency differences between mitochondrial fluorescence-defined subpopulations. These findings suggest that sperm mitochondrial abundance can potentially serve as an indirect, high-throughput marker of nuclear genomic heterogeneity within sires. This proof-of-concept framework establishes a foundation for future studies integrating sperm phenotyping, genome-wide allele-frequency analysis and functional validation to better characterize gamete-level heterogeneity.

Male↗

PubMedDate not supplied

[Convenience of vestibular surfaces of lower canines for accepting retention elements of removable partial denture].

Lower canines often appear as abutment teeth of partially edentulous dental arch. Crown contours of these teeth are mostly inconvenient for placing clasps. The convex vestibular surfaces with sufficient undercuts for placing retention elements are obligatory on lower canines but it is not common case. Aim of this paper was to confirm a high frequency of unexistence of buccomesial and buccodistal undercuts of the lower canines. Measuring of buccomesial and buccodistal undercuts on abutment lower canines was preformed on 50 diagnostic casts of lower jaw, belonging to Kennedy class I, where the canine was a border of shortened dental arch. For this procedure paralelometar Unit "Degussa" with a special measuring device was used. The undercut depth could be read directly within a range of 0-1.0 mm. Results show that unprepared lower canines have poor possibilities for retention removable partial denture with clasps. Our positive clinical experiences in recontouring vestibular surfaces of the abutment teeth point to two methods of making an artificial undercut: non-invasive (making an artificial undercut using composite materials) and invasive (using modified fixed restorations). Considering fact that vestibular surfaces of lower canines as abutment teeth are in most cases without undercuts, recontouring of this surface in almost all occasions is necessary. If vestibular undercuts don't exist, non-invasive techniques should always have advantages to invasive techniques. The vestibular surfaces of abutment teeth might be recontoured by using non-invasive techniques with minimal destruction of integrity of teeth. Lately, the composite materials are used for forming artificial undercut.

Cuspid↗

PubMed1987

Tissue compliance meter for objective, quantitative documentation of soft tissue consistency and pathology.

A new instrument is described, the tissue compliance meter (TCM), for quantitative and objective recording of soft tissue consistency. This quality is appreciated at present only by the subjective method of palpation. Use of the TCM therefore offers a method to quantify palpation of tissue consistency and to document findings objectively. The handheld instrument allows immediate and simple reading of the depth of penetration of a rubber disc at a known pressure. The relation between the achieved penetration and employed pressure expresses the compliance. The TCM consists of a rubber disc with the surface of 1 cm2 attached to a force gauge. The depth of penetration of the rubber tip is indicated by a disc which slides on the shaft of the force gauge. Normal values were established for men and women over muscles which are frequently affected by spasm. Tissue compliance measurement can document changes in soft tissue consistency which occur in muscle spasm, spasticity, swelling, tumors, lumps, hematomas, etc. Use of the TCM provides the most sensitive and earliest objective indication of either healing and resolution in soft tissue pathology or occurrence of complications. Changes in muscle tone such as reduction of spasm, tension, or spasticity can be recorded. The effects of different types of physical therapy can thus be documented objectively.

Connective Tissue↗

PubMed1998

[How can I keep up with my literature?].

To keep up with the literature, the author and his wife have personal home subscriptions to the 'big five' general medical journals, two top general science journals, and close to a dozen specialist journals. Two of the general medical journals are regularly read in more depth. Since computerized search systems permit almost immediate retrieval on whatever subject at whatever work location, the author keeps no filing system of the items of interest. For three (slowly growing) subjects that transgress the boundaries of the usual keywords of search systems, copies of papers are collected in piles: (a) important methodological papers (which may have been published anywhere, on any subject), (b) papers about concepts of the origin and evolution of diseases, and (c) papers of strong general interest. The disadvantage of not keeping track of the literature by a personal filing system is that the author regularly forgets about papers and books he already has; the advantage is that no time is spent keeping a personal filing system.

Humans↗