Resin-modified glass-ionomer setting reaction competition.

Resin-modified glass ionomers (RMGI) set by at least 2 mechanisms dependent upon reactant diffusion prior to gelation. Each reaction's kinetics and setting mechanism may rely on and/or compete with the other. In this study, we investigated RMGI setting reaction interactions using differential scanning calorimetry (DSC) by varying light-cure initiation times. A RMGI was analyzed with isothermal and dynamic temperature scan DSC with light-curing occurring immediately, or at 5 or 10 minutes after mixing as well as without light-activation. Results show that as time allowed for the acid-base reaction increased, the light-activation polymerization exotherm decreased. Conversely, analysis of DSC data suggests that earlier light-activation may limit the acid-base reaction and result in a different structured material. During early RMGI development, acid-base and light-polymerization reactions compete with and inhibit one another.

An appraisal of the use of secondment within a large teaching hospital.

INTRODUCTION: This study was undertaken in a large teaching hospital in Sheffield. It explores the use of secondment as a vehicle for practice, service and career development. AIM: To provide us with an understanding of the ways in which we utilize secondment opportunities, with a view to developing good practice guidelines that will help both the individual and the organization to maximize the potential in each secondment post. METHOD: A survey of nursing staff who had been on secondment during the previous year. Questionnaires were used to gather data from the senior nurse in each specialty directorate to develop an organizational (seconder) perspective and 20 secondees to provide an individual (secondee) perspective. RESULTS: Nurses tended to be seconded from clinical roles into specialist clinical roles or non-clinical roles, predominantly in areas of research, audit, practice development and teaching. Seconded posts were new roles for individuals and the majority were relocated to new work environments. Secondment was overwhelmingly seen as an opportunity, allowing individuals to develop new skills and knowledge, progress their career and gain a broader strategic perspective. However, there were a number of barriers to progress: lack of role definition for the organization and the individual; uncertainty about the future; falsely raised hopes that secondments would be extended; uncertainty about status; and difficulties adjusting to a new environment and culture within unrealistically short timeframes. CONCLUSIONS: Secondment use has become widespread throughout the National Health Service (NHS) and is a very positive and popular vehicle for staff and service development. The potential benefits are high but must be offset against the risks. This paper introduces an organizational risk assessment matrix which can be used to inform the development of effective secondment ventures.

A prospective audit of hospital-acquired deep vein thrombosis and pulmonary embolism.

The incidence of symptomatic deep vein thrombosis and pulmonary embolism acquired in hospital was studied, and the effectiveness of current thromboprophylaxis was assessed in an open study of 8648 admissions to the Doncaster Royal Infirmary between April and July 1994. On admission, all patients were assessed for their likely risk of thromboembolic problems according to THRIFT criteria. Treatment, prophylaxis, complications and outcome were recorded on discharge. A high risk sub-group was followed up for up to 42 days after discharge. The overall rate of clinically apparent hospital-acquired thromboembolic complications was 0.4% (n = 35). The rate of clinically apparent thromboembolic disease in the high risk group was 2.1% (n = 17). The incidence of thromboembolic problems appeared not to be reduce by prophylaxis apparently even when stratified by risk group. These findings suggest that thromboembolic complications may be less common than would be expected from published literature. Thromboprophylaxis as currently practised within our institution does not seem to affect the incidence of deep vein thrombosis or pulmonary embolism, and these results would appear to argue against a 'blanket' policy for pharmacological thromboprophylaxis.

Community case study: suicide cluster in a small Manitoba community.

OBJECTIVES: To review a cluster of suicides and suicidal ideation in a First Nations community. METHOD: The medical records and autopsy reports of the victims are reviewed. Collateral information obtained in the community is presented. A series of psychiatric assessments conducted at the local health centre in a 3-day period is outlined. The dilemma of developing appropriate treatment plans is discussed. RESULTS: In the period from February 3 to May 5, 1995, an isolated northern Manitoba First Nations community had 6 suicides in a population of less than 1500. Several other suicide attempts occurred. Community resources were strained. Alcohol was a factor in 4 of the suicides. Previous sexual assault was cited in 4 of 5 female cases presenting with suicidal ideation. CONCLUSIONS: Cluster suicide is a shared psychiatric and public health problem of major concern. Dreams of beckoning are common following a suicide. Communities should have a prepared plan to deal with a suicide. Resources should be provided quickly in an effort to prevent a cluster of suicides from occurring. High-risk individuals must be identified. Substance abuse must be addressed. Resources to assess and treat victims of sexual abuse must be available.

Response of tissue phosphate content to acute dietary phosphate deprivation in the X-linked hypophosphatemic mouse.

In order to evaluate a possible role for tissue phosphate or phosphorylated compounds in mediating the increase in plasma 1,25(OH)2D3 levels during dietary phosphate deprivation, renal cortical phosphate content has been measured in both normal and X-linked hypophosphatemic mice on a normal diet and also after acute dietary phosphate deprivation. We find that the metabolism of inorganic phosphate and phosphorylated organic compounds in the renal cortex of Hyp mice is not altered in response to their very low levels of serum phosphate. Skeletal muscle does not lose inorganic phosphate and/or phosphorylated metabolites to compensate for drastic loses of serum phosphate during acute dietary deprivation in either normal or Hyp mice. Furthermore, the chronic low level of serum phosphate and altered hormonal regulation in Hyp mice do not produce alterations in mineral composition of the bone with the possible exception that the stoichiometry of the apatite might be slightly different.

Characterization of the solid components of biological tissues by cross-polarization, magic angle NMR spectrometry.

A biological tissue is composed of cytosol, which can be investigated by high resolution nuclear magnetic resonance (NMR) spectroscopy, and membrane and particulate components, which yield NMR spectra similar to those of solids. In this review, the theoretical and technical requirements of recording NMR spectra of solids with cross polarization and magic angle sample spinning techniques are compared with the physical characteristics of the solid components of biological tissues. Current applications of cross-polarization, magic angle NMR spectroscopy to the investigation of membranes, mineral deposits and biosynthetic pathways are presented and discussed in terms of the biomedical questions to which this technique might be applied.