Trevor M. Jones

Return to work after traumatic brain injury: Cohort comparison and economic evaluation

Background: Returning to work (RTW) in the UK is problematic following TBI. Vocational rehabilitation (VR) is limited and efficacy or costs seldom reported. This study aimed to determine whether a TBI specialist VR intervention (TBI VR) was more effective at work return and retention 12 months after injury than usual care (UC). Secondary aims were to explore the feasibility of collecting economic data to inform a definitive trial. Method: Work outcomes of TBI-VR were compared to UC. Ninety-four participants (40 TBI-VR) with TBI resulting in hospitalization ≥48 hours, who were working at injury were followed up by postal questionnaire at 3, 6 and 12 months post-hospital discharge. Primary outcome was RTW. Secondary outcomes were functional ability, mood and quality-of-life. Health resource use was measured by self-report. Results: At 12 months, 15% more TBI-VR participants (27% more with moderate/severe TBI) were working than UC (27/36, 75% vs. 27/45, 60%). Mean TBI-VR health costs per person (consultant, GP, therapy, medication) were only £75 greater at 1 year. Secondary outcomes showed no significant baseline differences between groups. Discussion: More TBI-VR participants returned to work than UC. People with moderate/severe TBI benefitted most. This positive trend was achieved without greatly increased health costs, suggesting cost-effectiveness. This study justifies the need for and can inform a definitive Randomized Controlled Trial (RCT).

Moisture uptake and tensile strength of bulk solids.

An apparatus is described in which bulk solid handling properties can be examined over a wide range of humidities. It is shown that constant temperature and relative humidity can be maintained. The apparatus can also be used to study the effect of cycles of humidity changes. The rate of moisture uptake by loosely packed and tapped beds of six pharmaceutical materials was found to be dependent upon bed depth but independent of bulk density. The tensile strengths of the bulk solids changed when they were subjected to high relative humidities.

Seeking support after hospitalisation for injury: a nested qualitative study of the role of primary care

BACKGROUND In the UK, studies suggest that the transition from hospital to home after an injury can be a difficult time and many patients report feeling inadequately prepared. Patients often use primary care services after hospital discharge. These consultations provide opportunities to consider problems that patients experience and to facilitate recovery. Little is known, however, about how patients and service providers view care after hospital discharge and the role played by primary care services, specifically GPs. AIM To identify good practice and unmet needs in respect of post-discharge support for injured patients. DESIGN AND SETTING Qualitative study using semi-structured interviews at four sites (Bristol, Leicester/Loughborough, Nottingham, and Surrey). METHOD Qualitative interviews with 40 service providers and 45 hospitalised injured patients. RESULTS Although there were examples of well-managed hospital discharges, many patients felt they were not provided with the information they needed about their injury, what to expect in terms of recovery, pain control, return to work, psychological problems, and services to help meet their needs. They also described difficulty accessing services such as physiotherapy or counselling. Service providers identified problems with communication between secondary and primary care, lack of access to physiotherapy, poor communication about other services that may help patients, GP service and resource constraints, and difficulties in providing information to patients concerning likely prognosis. CONCLUSION Discharge from hospital after an injury can be problematic for patients. Changes in both secondary and primary care are required to resolve this problem.

The intraparticulate structure of calcium phosphate

It is well known that calcium phosphate B.P.C. requires more granulating fluid to produce a coherent mass during wet granulation than other tablet diluents such as lactose or starch. Recently Ganderton & Hunter (1971) reported that calcium phosphate showed uncontrollable ball growth during pan granulation at moisture contents in excess of 191 % v/v and rapid ball growth above 174% v/v. Furthermore in granulation by massing and screening, suitable granules were prepared only over a narrow range of lower moisture contents (117-157 % v/v). Assuming the particle density of calcium phosphate to be approximately 3.0 g ~ m ~ and allowing for the 10% w/v dextrose monohydrate dissolved in the granulating fluid (Ganderton & Hunter, 1971) these ranges of liquid content are equivalent to moisture contents of between 40 and 60% w/w dry basis. This agrees well with work in these laboratories which has shown that calcium phosphate shows no measurable change in tensile strength at liquid concentrations up to 45-50% by weight of the dry mass (Eaves & Jones, 1971,1972a, b). This has been attributed to the porous nature of the individual particles of calcium phosphate, a phenomenon inferred from the gross difference in the surface areas obtained firstly by Nitrogen adsorption and secondly by calculation from the size distribution data assuming the particles to be non-porous spheres of equivalent volume (Eaves & Jones, 1972a). It is assumed that the intraparticulate porosity is such that at low moisture contents the liquid becomes located within the particles thus preventing the formation of pendular liquid bridges between adjacent particles. Once the intraparticle voids are saturated, the moisture can exert an influence at the surface of the particle by increasing tensile strength or, as in Ganderton and Hunter’s work, by assisting aggregation and densification. This is in agreement with the suggestion of Glushkov, Karnaushenko & Platanov (1969) that the internal friction of materials composed of porous particles increased only after saturation of the internal structure. Fig. 1A and B are scanning electron micrographs obtained from a ‘Stereoscan’ Mark

The packing properties of moist bulk solids

The specific volumes of three bulk solids at moisture contents up to 50% w/w (dry basis) under various consolidating stresses have been shown to be dependent on the nature of the bulk solid. The values obtained can be related to the intraparticulate porosity and inherent cohesiveness of the dry materials. The influence of moisture on the packing properties and tensile strength of the three bulk solids is discussed in terms of the granulation process.

The equivalence of Oxytetracycline tablets B.P.

The equivalence of oxytetracycline tablets B.P. TREVOR M. JONES, PETER c. RISDALL AND MALCOLM FRIER* Research Department, The Boots Co. Ltd., Nottingham The inequivalence of bioavailability of oxytetracycline hydrochloride from capsules has been known for several years (Brice & Hammer, 1969; Blair, Barnes & others 1971). The B.P. tablet contains the dihydrate and a recent study has shown that the dissolution at pH 2.0 varies between products obtained from different manufacturers and between batches from one source (Groves, 1973). We have carried out bioavailability studies on formulations giving equivalent dissolution profiles at pH 2.0 and these have shown markedly different serum levels in volunteers. A more critical examination of the conditions of the dissolution test suggests that the pH of the dissolution medium is an important parameter. The percentage of drug released from a tablet in a given time was found to be directly related to the pH-solubility profile which exhibits a minimum at pH 5 (Merck Index, 1968). Dissolution tests at this pH highlight differences in serum levels from different formulations (for example see Table 1).

The construction of failure loci for a sand using a direct shear box

Abstract The failure properties of a close cut sieve fraction of sand have been measured using a direct shear box tester. It is shown that the conditions of bed preparation are important in defining the porosity changes in the shear zone during shear; in particular it was necessary to standardise the method of preparation prior to and after the application of consolidating loads. A shear cell with a shallow base has been used to reduce the amount of material below the shear zone. Using this cell and the standardised method of sample preparation it is shown that a failure surface for the sand can be accurately constructed by calculating the height of the shear zone and the changes in porosity during shear.

The influence of the surface tension of pendular bonds on the tensile strength of moist beds of bulk solids

T. EAVES* AND T. M . JONES Department of Pharmacy, University of Nottingham, Nottingham, U.K. The tensile strength of a bed of fine particle sized material depends upon a number of factors of which the main are, particle size and distribution, particle shape, surface roughness, chemical constitution and moisture (Eaves, 1971). For non-cohesive materials it was found that increasing the moisture content increased the tensile strength of a bed at a fixed state of packing to a plateau where it is recognized that the moisture exists as pendular bonds between adjacent particles. In this state, the tensile strength of an ideal system of monosize spheres may be estimated from an equation reported by Pietsch (1968). For glass powder, which possessed negligible tensile strength when dry, a reduction in the surface tension of the wetting fluid produced a reduction in tensile strength of packed beds at fixed porosities over a range of liquid contents. The tensile strength at constant liquid content and packing density increased linearly with surface tension, consistent with the previously mentioned equation. For materials with inherent tensile strength at dryness, increasing the moisture content was found to increase the strength of the bed at a fixed packing density to a maximum and thereafter to cause a decrease in tensile strength due to disruption of the inherent cohesive forces. Beds of fine particle sized sodium chloride wetted with a fluid of lower surface tension than saturated sodium chloride solution showed a similar pattern of tensile strength changes but non quantitative reduction in values. This is attributed to a change in the location of the pendular bonds. For calcium phosphate, however, liquid contents of up to about 50% by weight and of varying surface tensions were shown to produce little or no change in tensile strength and this is attributed to the location of liquid in the intraparticle voids where it is less likely to affect particle-particle interactions. The bulk solids used were powders characterized in terms of size, size distribution, shape and density. The wetting fluids consisted of 5 % w/w Tween 80 in either distilled water or a saturated solution of the solid being investigated. All measurements were made on pre-dried beds of bulk solids in a controlled temperature and humidity environment (Eaves & Jones, 1970) using tensile testing apparatus similar in design to that of Ashton, Farley & Valentin (1 964).