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Biomedical subjects

H Moseley

Publications and source records attributed to H Moseley.

At least 91 records · Page 5Linked to original sources
PubMed1987

Ultrasound transmission time: an in vivo guide to nail thickness.

Human fingernail thickness was measured distally in 39 subjects using an adapted electronic micrometer and ultrasound transmission time was measured both distally and proximally. Distal ultrasound nail transmission time correlated well with micrometer measurements. There was a clear rank order of distal and proximal nail transmission times: thumb greater than index greater than middle greater than ring greater than little fingers. Male nails had greater transmission times than female nails on the ring and little fingers. Distal nail transmission time was 8.8% less than proximal transmission time.

Adult↗
PubMed1986

Arterial to end tidal carbon dioxide tension difference during caesarean section anaesthesia.

The relationship between arterial carbon dioxide tension and end tidal carbon dioxide tension was studied in 19 patients during general anaesthesia for Caesarean section. Thirteen patients scheduled for elective abdominal hysterectomy formed a nonpregnant group. There was significant correlation between arterial and end tidal CO2 tensions in both groups. During Caesarean section, this difference was significantly less than in the nonpregnant group.

Adult↗
PubMed1986

An assessment of visible-light polymerizing sources.

Measurements were made of the spectral distribution of light emitted from five commercially available visible-light polymerization units. All emissions peaked between 400 and 500 nm but the 'functional' irradiance varied by a factor of 20 for the sources investigated. Timer checks revealed errors of up to 20%. Light output was plotted as a function of time and, after 60 s, varied from-15% to +38% of the initial level. The decrease in irradiance with distance from the end of the guide was such that irradiance at 20 mm was between 20% and 40% of that at 2 mm. The light distribution across the face of each light guide was investigated and significant inhomogeneities discovered. An ultraviolet light (UV) hazard assessment was performed and it was concluded that none of the light sources presented a hazard to the operator in normal use.

Chemical Phenomena↗
PubMed1986

A system for solar radiation data storage and analysis.

It is important for photodermatologists to have an accurate and continuous measurement of the ultraviolet radiation reaching the ground. This implies the establishment of a network of detectors, but for this to be a practical reality, it is essential that an accurate and convenient system be adopted for data storage and analysis. To this end we have developed a system which meets the following criteria: it is automatic; component costs are low: it uses a home microcomputer costing 400 pounds (less than $600); because processing is done by a computer, it is flexible; also, for the same reason, there is the facility for on-line display and on-line analysis; there are no significant errors: a modified computer circuit produces a temperature coefficient of 30 ppm/degrees C; reliability is good: 12 d of data were lost from all causes, including development, during 12 months of continuous use. The system described could form the basis of a practical UV-recording network.

Data Collection↗
PubMed1986

The prevention of vitamin D deficiency in the elderly.

Vitamin D deficiency is common in the house-bound and institutionalised elderly population of Britain. A study of patients over 65 years discharged with a diagnosis of osteomalacia from Greater Glasgow Health Board hospitals between 1970 and 1981 inclusive showed a low incidence in the 65 to 74 years age group but a steeply rising incidence in older age groups. The majority (83%) of patients were female. The fortification of margarine, butter and milk with concentrations of vitamin D acceptable to the general population does not produce significant elevations in serum 25-hydroxyvitamin D (25-OHD) levels in vitamin D-deficient elderly patients. Low intensity background ultraviolet radiation (UVR) and intermittent high intensity UVR produce significant elevations in serum 25-OHD levels in elderly patients but both methods have disadvantages which limit their widespread use. Vitamin D supplements equivalent to 10 micrograms daily produce significant elevations in serum 25-OHD levels in vitamin D-deficient elderly patients. A vitamin D supplement policy for the housebound and institutionalised elderly population of Britain is required.

Aged↗
PubMed1984

The suitability of diazochrome KBL film for UV dosimetry.

A promising material for use in a UV film badge dosemeter is diazo film. The optical density of this substance changes on exposure to ultraviolet radiation. The present paper reports some of the relevant factors in the processing of the film and also on its spectral sensitivity. It is evident from our results that development time and volume and concentration of ammonia solution should be standardised. However, after the film has been developed, it is not affected by subsequent UV exposure or by storage for up to one month. Although maximum sensitivity occurs at 405 nm, there is still an easily measurable response at 254 nm. It is concluded that provided procedures are standardised, Diazochrome KBL film is an inexpensive, convenient material for a UV film badge dosemeter with measurable sensitivity down to 254 nm.

Film Dosimetry↗
PubMed1984

Routes of clearance of radioactive water from the rabbit vitreous.

The movement of water to and from the vitreous across the retina and pigment epithelium is important in relation to an understanding of such conditions as retinal detachment and its surgical cure, central serous retinopathy, and retinal oedema. Experiments were carried out to determine the main routes for removal of water injected into the vitreous and to see if the removal could be explained on the basis of diffusion or whether bulk flow was also implicated. 25 microCi of 3H2O in 25 microliter were injected into a central position in the vitreous humour of living rabbits under general anaesthesia. For 9 animals blood was collected from one of the 4 vortex veins draining the choroid and the radioactivity in the samples measured. For another 6 rabbits similarly injected the radioactivity in samples of aqueous humour was determined. The percentage of injectate recovered from the vortex vein blood ranged between 13% and 38%, mean 25 +/- 3%. The percentage of injectate recovered from the aqueous humour ranged between 1.2% and 5.2%, mean 2.8 +/- 0.6%. Analysis of the time course of isotope activity in the samples revealed a mean transit time from the mid vitreous to the choroid of 32 +/- 2 minutes, and from the mid vitreous to the anterior chamber of 84 +/- 3 minutes. By means of a computer model it was calculated that diffusion alone could effect this transfer; if active transport were involved in the transport of 3H2O to the choroid, this was not a limiting factor under the conditions of the experiment.

Animals↗
PubMed1983

Measurement of daylight UVA in Glasgow.

Measurements of daylight UVA have been carried out in Glasgow using a UVA-band detector and a spectroradiometer, both with the aperture window horizontal. Daily energy densities, defined as the total UVA energy each day per unit area, were obtained for the period November 1980 to May 1982. Levels rose from a mean December daily energy density of 4 J cm-2 to an average of 69 J cm-2 in June, with considerable fluctuations from day to day and with up to seven-fold changes observed on consecutive days. The UVA level sometimes varied rapidly during the day, with differences of up to a factor of six in successive 10 min periods. The daily temporal distribution of UVA for summer and winter, and the measured daylight spectra are presented. The spectroradiometer contained a double-grating monochromator used at a band-width of 1 nm. Measurements made by the spectroradiometer were compared with earlier published findings o solar UVA doses received by 56 patients who were photosensitized by 8-MOP in the course of PUVA therapy. It is shown that the median dose represented only 12 min daylight exposure and this indicates that the majority of patients to take care to avoid unnecessary exposure. However, the maximum dose was equivalent to some 84 min exposure to daylight UV and so there is clearly scope for a considerable reduction in exposure in some cases.

PUVA Therapy↗
PubMed1983

Mathematical modelling of aqueous humour outflow from the eye through the pores in the lining endothelium of Schlemm's canal.

Aqueous humour leaves the eye mainly by way of pore openings in vacuolar swellings in the endothelial cells which line the wall of Schlemm's canal. Calculation of the resistance to fluid flow offered by these small pores requires data on their incidence and dimensions linked to a suitable mathematical model. Data are derived from scanning electron microscopy (SEM) studies conducted on rhesus monkey eyes maintained at an intraocular pressure (IOP) of either 8 or 15 mmHg and on human eyes either untreated controls or treated with pilocarpine. Mathematical models of flow through the pore openings are developed. Application of a Venturi tube model to the SEM data shows that the pore resistance of rhesus monkey eyes at 8 mmHg was seventeen times greater than that at 15 mmHg while the pore resistance in untreated human eyes was five times greater than in eyes which received pilocarpine.

Animals↗
PubMed1983

An assessment of new dental ultraviolet sources and u.v.-polymerized fissure sealants.

The performance of six dental ultraviolet (u.v.) sources was assessed to establish minimum output requirements and possible u.v. hazards. Exposure criteria for u.v.-cured materials (Nuva-seal P.A., Nuva-cote P.A., Nuva-fil P.A., Lee-seal, u.v.-Dentoseal, Uviobond, Visiobond) were assessed by determining setting time-intensity characteristics, u.v. transmission and microhardness as a function of u.v. intensity and depth. A minimum intensity of 10 mW cm-2 was required for adequate curing and both Nuva-seal P.A. and Nuva-cote P.A. set well in depth with realistic exposures. Total u.v. outputs, average intensities and spatial distributions were assessed for the u.v. sources, most of which were well above minimum requirements. Ultraviolet spectra and maximum permissible exposure measurements indicated that all of the sources were safe in normal use.

Chemical Phenomena↗