Showing papers by "University of Bedfordshire published in 1989"

The chemical and physical speciation of trace metals in fine grained overbank flood sediments in the Tyne basin, north-east England

Abstract: Deposition of fine sediment contaminated by heavy metals on floodplains in the Tyne basin, north-east England, during a major flood in August 1986 provided an unusual opportunity to investigate the chemical and physical speciation of metals in overbank fines. Selective extractions and heavy-liquid analyses were used to assess the chemical forms of sediment-associated metal and the relationship between grain size, density and metal concentration and to identify sources of metalliferous material. Generally the highest concentrations of trace metals were found in the 500–250 μm size range and in the heavier density fractions (>3.3 gml−1), though more than 60% of metals reported to the lightest (<3.3 gml−1) density product. The principal source of metals appeared to be reworked alluvium contaminated by historic mining activity. Metal concentrations in flood sediment decrease downstream from former mining areas though at varying rates depending on the physical propeties and chemical phase of individual metals. With the exception of Cu (dominated by lithogenic fraction), metals are primarily associated with Fe/Mn oxides (Pb, Zn) and to a lesser extent with carbonates (Cd, Zn), organic matter (Zn, Cu) and an operationally defined exchangeable (Cd) component. In the upper and middle parts of the Tyne basin physical processes of downstream sediment metal content reduction were found to predominate, while in the lower reaches of the Tyne sediment metal transport appears to be governed by chemical sorption-desorption processes associated with Fe/Mn oxides and organic material. Finally the results of the study are discussed in a wider context of particulate metal transport in rivers and recommendations are made for refining density-based models of metal dispersal.

Alternating pressure pad

Abstract: An alternating pressure pad has two sets of alternately inflatable cells. The alternately inflatable cells overlie additional base cells in a lower layer of the mattress. These base cells are all simultaneously inflated whilst each of the sets of upper cells are repeatedly inflated and deflated in alternation over an inflation and deflation cycle. During a cycle each set of upper cells is deflated at least once while the patient is primarily supported by the other inflated set of cells. During each inflation and deflation cycle, the additional base cells are reduced in pressure at least once. In this way, even if a part of the patient is temporarily supported only on the lower base cells, the support pressure is temporarily reduced each cycle to minimize pressure effects on the patient.

Ventilators for promoting lung function

Abstract: A ventilator for inducing or assisting lung function in humans is characterized by a control system that provides for semi-automatic operation in which a single complete ventilation cycle in accordance with predetermined ventilation parameters (tidal volume, durations of inhalation and exhalation phases) is initiated by operation of a trigger. The ventilator is particularly useful in one-man resuscitation by CPR. The control system may require a discrete trigger operation to initiate each successive ventilation cycle or it may provide for continuous operation with timed successive cycles, in the manner of an automatic ventilator, by holding or latching the trigger. Various embodiments based on gas-powered ventilators are disclosed but the invention is also applicable to electrically operated or controlled ventilators. In a typical embodiment (FIG. 1) the output line (6) of a pneumatic oscillator is controlled by a diaphragm (22) held closed by a spring (36) loaded by a trigger (31) that when operated relieves the spring load and permits the diaphragm to open the output line. The output line pressure then acts on the diaphragm to hold the output line open until output pressure falls at the termination of the inhalation cycle, whether or not the trigger is released before that instant.

Minimum eliciting patch test concentrations of cobalt

Abstract: In sensitized subjects, minimum eliciting levels of cobalt were estimated using patch tests with aqueous cobalt chloride on both normal skin and on skin pretreated in various ways to enhance penetration and reactivity. 6 reacted to 10,000 ppm and 1 gave an equivocal reaction to 1000 ppm aq. cobalt. Pretreatment of the patch test site for 24 h with surfactant enhanced reactivity, reducing the minimum eliciting concentration to 1000 ppm cobalt chloride in 1 subject, to 100 ppm in 2 subjects, and in 3 subjects to 10 ppm aqueous cobalt chloride. No reactions were obtained at 1 ppm. EDTA was effective in reducing the response to aqueous cobalt.

Colored hydrogel objects and their production-containing a water-insoluble opaquing agent

Abstract: Shaped organic polymer hydrogels, especially contact lenses, are provided with opaque or translucent coloring so as to be capable of masking effectively any underlying color, eg the natural color of the eye The hydrogel may be rendered opaque by precipitation in situ of a white or yellow water-insoluble, inorganic or organic material eg barium sulphate or an optical brightener and then colored with a suitable dyestuff

Improved contact lens design

Abstract: A contact lens having its posterior only or posterior and anterior surface configured for astigmatic correction of the eye of a wearer and allowing an arbitrary amount of refractive correction of error in an eye of a wearer. The refractive error can be corrected by a proportionate distribution of design geometry between the anterior and/or posterior surface of the lens.

Soft contact lens for the correction of astigmatism

Abstract: The invention is incorporated to a soft contact lens. This lens has a concave posterior surface for fitting to the eye of a wearer, and a convex anterior surface for exposure from the eye of a wearer. The soft contact lens contains a correction for the eye having a component of astigmatism. A novel posterior surface has a central refractive segment sufficient in dimension to afford pupil coverage and therefore correction to the vision of the eye of the wearer. This central portion is configured for imparting a component of astigmatic correction of the eye of a wearer in a first central zone containing the refractive segment. When the contact lens is worn, this first central zone is juxtaposed to the central portion of the eye of the wearer. The posterior surface at the first central zone is surrounded by a posterior zone for fititng the soft contact lens to the eye of the wearer. This posterior zone about said first central zone has as its main purpose the maintenance of the contact lens to the eye of the wearer. Since by exclusion, it does not have substantial pupil coverage, it is tailored to the keratometry of the eye and enables the lens to be maintained on the eye. By combining the posterior central zone with the anterior portion of the lens, an arbitrary amount of refractive correction of error to the eye of the wearer can be accommodated.

Cross-correlation apparatus and methods

Abstract: An apparatus and method for processing first and second signals, the second signal representing information which is delayed in time with respect to correspoonding information represented by the first signal and there being included in the information represented by each signal information which represents a common effect, occurring at the same time, in each of the two signals. The apparatus includes correlating means which generate first data suitable for producing a positive time correlation curve from the two signals and second data suitable for producing the equivalent of a negative time correlation curve from the two signals or an autocorrelation curve from either one of the two signals. The information representing the common effect results in data common to both first and second data. One of the first and second data is therefore subtracted from the other, thereby removing or substantially reducing the information representing the common effect. The apparatus and method are particularly suited for measuring the speed of travel of a cable in a cable making machine, where lateral movements of the cable away from its desired path produce a common effect on sensors spaced lengthwise of the direction of travel.

Structural effects on the antitumour activity of a series of di(4‐substituted phenyl)tin dichloride complexes with nitrogen‐donor ligands

Abstract: Investigation of the antitumour activity of a series of diorganotin dichloride complexes (4-ZC6H4)2SnCl2·L2, where Z = OMe, Me, F, Cl, and CF3 and L2 = 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen) and 2-aminomethylpyridine (amp) is reported. A number of these complexex are shown to exhibit reproducible activity in vivo towards P388 lymphocytic leukaemia in mice. 1H NMR data are reported for an extended series of (4-ZC6H4)4Sn and the parent dichlorides (4-ZC6H4)2SnCl2 of the above-mentioned complexes. A correlation is reported between Hammett substituent constants and 1H chemical shift data. Attempts are made to relate the antitumour activity of the complexes to various structural factors. The dependence of antitumour activity on the electronic effect of group Z and the nature of the ligand L2 is demonstrated.

Feeding trough for animals

Abstract: This invention relates to feeding throughs for animals particularly, pigs. The feeding trough has an elongate trough member (10) sub-divided by lateral partitions into individual compartments (11). The width (7) of the compartments (11), the height (3) of a front wall (13) of the trough over which the animal's head extends, and a canopy (15, 16) which restricts the space within the compartment into which the animal's head can reach are all designed erogonomically with respect to a range of animals intended to use the trough. The base of the trough is at floor level (18) and the front wall (13) extends from said floor level (18) to a predetermined minimum brisket height (3) of a predetermined smallest size of pig intended to feed. The trough member has an inner front wall (14) which extends angularly downwards and inwards of the trough to terminate at floor level (18) and an inner rear wall (17) which extends angularly downwards to terminate at a predetermined height above floor level at said mean reach. A canopy (15, 16) overlying the trough member and extends inwards and downwards to meet the inner rear wall (17) at the predetermined mean neck angle of the mean weight of pig at a position equal to the maximum nose-to-crown length of the predetermined largest pig. Partitions are spaced along the trough at intervals equal to the maximum shoulder width of the largest pig. Mathematical expressions have been derived to enable the dimensions to be calculated knowing the weight of pig and the height above the floor of the feed.

Electrochemical reduction-oxidation reaction and apparatus

Abstract: An electrochemical cell (1) including an electrode comprising Magneli phase titanium oxide is disclosed for use with reduction oxidation reactions The use of the Magneli phase titanium oxide electrode advantageously inhibits certain redox back reactions

Manufacturing Industry, Consultants and 1992

Abstract: In the run‐up to 1992 UK manufacturers should be scrutinising the efficiency of their factory operations as well as their marketing efforts. A great deal of advanced manufacturing technology is available to assist UK manufacturers to improve their methods of production and to enhance product quality. UK management should be examining ways in which they can take advantage of this technology and can be assisted in this technically complex task by taking advantage of independent consultants. The Department of Trade and Industry can offer smaller companies financial assistance with the costs of consultancy through a range of initiatives. Uptake of these initiatives has been generally encouraging but UK manufacturers appear to be slow to take advantage of the Manufacturing Initiative.

The ultraviolet microscopic transmission characteristics of human stratum corneum.

Abstract: Synopsis This study has evaluated the ultraviolet light transmission characteristics of human stratum corneum at the single cell level using a low light level video microscope to measure the mean percentage transmission of light at different wavelengths and the variation in transmission across the stratum corneum. Stratum corneum was isolated by an enzymic technique and examined on a low light level UV video microscope. Quantitative evaluation of the transmitted monochromatic light for the underside of the layer was measured directly using a Kontron UNIPS image processor or indirectly with a Quantimet 920 image processor after video recording. Transmission distribution histograms were obtained from samples of stratum corneum taken from human breast, scalp, abdomen and leg. Mean transmission values were also derived and compared with diffuse transmission values obtained using the same tissue mounted on an integrating sphere. The UV microscopic transmission characteristics of enzyme separated stratum corneum clearly demonstrated that this structure was not an ideal diffuser. Uniform light intensity on the surface of the stratum corneum led to areas of transmitted intensity in close proximity that differed by factors ofthree to six fold, e.g. between regions of high (>70%) and low (<20%) brightness. However, the average transmission was found to be compatible with published data obtained by diffuse transmission spectrophotometry, taking into account the enhanced transmission arising from stratum corneum immersion in phosphate buffered saline. This was confirmed by the elevated values obtained by diffuse transmission spectrophotometry in this study for samples of stratum corneum prepared for UV microscopy being higher than these found in published data. It is obvious from these findings that viable cells in the epidermis are not exposed to a uniform incident light intensity even when this is true for the surface of skin. Studies of skin response to ultraviolet light at the single cell level must take account of the possibility of preferential exposure of specific sites in any subsequent explanation of cell sensitivity. This is in addition to the already well established cell cycle dependent ultraviolet sensitivity.

Tyrosine in Photographic Gelatin

Abstract: The amino acids tyrosine and phenylalanine have been determined in photograp, hic gelatin using the technique of second derivatrve spectroscopy. Results confirm earlier reports that gelatin produce...

Pupil Talk in Biology Practical Work--A Preliminary Study.

Abstract: The development of a framework for analysing pupil talk is described and the reliability of scoring transcribed conversations using the framework discussed. Preliminary findings from this study on the talk occurring during small group practical work in biology focus on the forms of verbal interaction that occur, patterns of verbal interactions shown by individuals within groups and the possible link between such patterns and roles within the groups.

Device for connecting a container to a dispensing head

Abstract: A connector for a bottle of concentrate for a carbonating apparatus has a cylindrical body the upper end of which carries a structure defining a number of radially extending baffle and a central opening through which a dip tube may be inserted into the bottle. A latching ring for connecting the connector to the carbonation apparatus is carried by the body at a position outwardly thereof and lower than the baffle structure. The latching ring is constructed to snap on to a corresponding boss on the carbonation apparatus. The bottle is detached from the carbonation apparatus, after exhaustion of the contents, by removal of a tear-off strip which connects the latching ring to the body of the connector. To facilitate connection of a fresh bottle of concentrate to the apparatus, the apparatus includes a housing which is detachable from the remainder of the apparatus and which carries the dip tube and other elements co-operable with the connector for attaching the bottle.