Aspects of Silicon Solar Cells: Thin-Film Cells and LPCVD Silicon Nitride

This thesis discusses the growth of thin-film silicon layers suitable for solar cells using liquid phase epitaxy and the behaviour of oxide LPCVD silicon nitride stacks on silicon in a high temperature ambient.¶ The work on thin film cells is focussed on the characteristics of layers grown using liquid phase epitaxy. The morphology resulting from different seeding patterns, the transfer of dislocations to the epitaxial layer and the lifetime of layers grown using oxide compared with carbonised photoresist barrier layers are discussed. The second half of this work discusses boron doping of epitaxial layers. Simultaneous layer growth and boron doping is demonstrated, and shown to produce a 35um thick layer with a back surface field approximately 3.5um thick.¶ ..

Boron doping of silicon layers grown by liquid phase epitaxy

This paper presents the results of a study of the incorporation of boron into silicon layers grown from a tin melt by liquid phase epitaxy. Boron was added to the melt through the use of boron-doped silicon source wafers. There is a large discrepancy between the amount of boron incorporated into the epitaxial layer and that available in the source wafer. This mismatch is explained by the gradual removal of boron from our system, most likely as a result of boron precipitation in the tin melt. This situation allows for control of the boron profile by adjusting the cooling rate and adding a dwell time. In this way, we have grown an epitaxial layer with an abrupt and highly doped p-type region at the epitaxial layer/substrate interface. This is useful for thin film solar cell applications as it allows the growth of a back surface field and a lightly doped bulk in a single growth step

Routine resite of peripheral intravenous devices every 3 days did not reduce complications compared with clinically indicated resite: a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Peripheral intravenous device (IVD) complications were traditionally thought to be reduced by limiting dwell time. Current recommendations are to resite IVDs by 96 hours with the exception of children and patients with poor veins. Recent evidence suggests routine resite is unnecessary, at least if devices are inserted by a specialised IV team. The aim of this study was to compare the impact of peripheral IVD 'routine resite' with 'removal on clinical indication' on IVD complications in a general hospital without an IV team.</p> <p>Methods</p> <p>A randomised, controlled trial was conducted in a regional teaching hospital. After ethics approval, 362 patients (603 IVDs) were randomised to have IVDs replaced on clinical indication (185 patients) or routine change every 3 days (177 patients). IVDs were inserted and managed by the general hospital medical and nursing staff; there was no IV team. The primary endpoint was a composite of IVD complications: phlebitis, infiltration, occlusion, accidental removal, local infection, and device-related bloodstream infection.</p> <p>Results</p> <p>IVD complication rates were 68 per 1,000 IVD days (clinically indicated) and 66 per 1,000 IVD days (routine replacement) (<it>P </it>= 0.86; HR 1.03; 95% CI, 0.74-1.43). Time to first complication per patient did not differ between groups (KM with log rank, <it>P </it>= 0.53). There were no local infections or IVD-related bloodstream infections in either group. IV therapy duration did not differ between groups (<it>P </it>= 0.22), but more (<it>P </it>= 0.004) IVDs were placed per patient in the routine replacement (mean, 1.8) than the clinical indication group (mean, 1.5), with significantly higher hospital costs per patient (<it>P </it>< 0.001).</p> <p>Conclusions</p> <p>Resite on clinical indication would allow one in two patients to have a single cannula per course of IV treatment, as opposed to one in five patients managed with routine resite; overall complication rates appear similar. Clinically indicated resite would achieve savings in equipment, staff time and patient discomfort. There is growing evidence to support the extended use of peripheral IVDs with removal only on clinical indication.</p> <p>Registration number</p> <p>Australian New Zealand Clinical Trials Registry (ANZCTR) Number ACTRN12608000421336.</p

Nadine Gordimer: De-Linking, Interrupting, Severing. Introduction

In a reflection about her own positionality, seen against the provisional and uncertain background of the “breaches and interstices that the ravelling-out of apartheid colonialism produced” (Writing 128), Nadine Gordimer recounts how her artistic calling preceded her political activism. In this essay, entitled “That Other World that Was the World,” she explains that before she committed herself to the anti-apartheid struggle per se, she had mingled with black writers, painters, and actors, an..

Psychiatric nurses’ views on criteria for psychiatric intensive care: acute and intensive care staff compared

Aim: To explore and investigate differences between the views of qualified nurses working in psychiatric intensive care units (PICUs) and acute care wards on which patients are appropriate for PICU care. Background: Previous research on the area of psychiatric intensive care highlights the great differences that exist in all aspects of service provision, from unit size and staffing levels to treatment approaches and physical environment. One of the most common areas of controversy is the type of client behaviour that warrants admission to the PICU. Method: Structured interviews of 100 qualified nursing staff (in the London area, England) working on either acute or PICU wards were used to gather data on appropriate and inappropriate referral to PICUs. Comments made during the course of the interviews were also collected and subjected to content analysis. Findings: There was evidence to support the hypothesis that acute ward staff considered patients suitable for PICU care at a lower level of risk than PICU staff thought appropriate. In comparison to acute ward nurses, those working in PICUs attended to a broader range of factors when considering suitability for admission to PICU. Appropriate reasons for transfer fell into five groups: risk to others; risk of intentional harm to self; risk of unintentional harm to self; therapeutic benefit from the PICU environment; and legitimate acute ward care problem. Inappropriate reasons for transfer fell into four groups: low risk to others and/or self; illegitimate acute admission care problems; patient belongs elsewhere; policy issues. Conclusion: The study opens up a range of issues not previously studied in relation to the use of PICUs and the intricate relationship of this use with the available acute care wards and other services. These findings and their implications for the care of acute and disturbed psychiatric patients are discussed

Encapsulated Dicopper(I): Kinetic or Thermodynamic Stabilization?

Cyclic voltammetry of a series of air-stable dicopper(I.I) azacryptates indicates that some, including those with heterocyclic-N-donor spacers, are thermodynamically unstable towards oxidation by O2; in this case outer-sphere oxidation by Fc+ or Ag+ is readily achieved

Electronic health records for biological sample collection: feasibility study of statin-induced myopathy using the Clinical Practice Research Datalink.

AIMS: Electronic healthcare records (EHRs) are increasingly used to store clinical information. A secondary benefit of EHRs is their use, in an anonymized form, for observational research. The Clinical Practice Research Datalink (CPRD) contains EHRs from primary care in the UK and, despite 1083 peer-reviewed research publications, has never been used to obtain pharmacogenetic samples. Using a statin-induced myopathy paradigm, we evaluated using the CPRD to obtain patient samples for a pharmacogenetic study targeting 250 cases and 500 controls from UK general practitioner (GP) practices. METHODS: The CPRD identified potential patients fitting specific case-definition criteria (active rhabdomyolysis or creatine phosphokinase > four times the upper limit of normal), and corresponding GP practices were asked to invite patient participation. Consenting patients were requested to provide either saliva or blood samples and to complete an ethnicity questionnaire. Control subjects were recruited from the same GP practice (saliva) or a small number of practices (blood). Samples were forwarded for DNA extraction. RESULTS: Thirty-six months of recruitment yielded DNA samples from 149 statin-induced myopathy cases and 587 tolerant controls. Data show that contacting patients through their GP is a reliable method for obtaining samples without compromising anonymity. Saliva collection directly from patients was considerably less effective than blood sampling. After 10 months of recruitment, saliva sampling was suspended in favour of blood sampling. CONCLUSIONS: We demonstrate the potential of EHRs for identifying accurately phenotyped cases and controls for pharmacogenetic studies. Recruitment was successful only because of the willingness of GP practices to participate and the existence of strong doctor-patient relationships. The present study provides a model that can be implemented in future genetic analyses using EHRs