330 research outputs found
Interactions of fluorophores with complex surfaces and spectroscopic examinations of ancient manuscripts
In the first part of this thesis, it was found by fibre-optic fluorescence spectroscopy, that the greening of fabrics washed in optical brighteners is due to a reabsorption effect. The quantum yield of fluorescence of the optical brighteners OB15, OB36 and OB49 in water are , and respectively. Their respective fluorescence natural lifetimes are , and ps. In solution, the excited state of OB15 experiences more competing relaxation processes as the solvatochromic shift increases. OB49 displays the opposite trend.
A literature cellulose model surface is employed as a cotton mimic for evanescent wave fluorescence studies. Two model greases are similarly developed and used, and a third is presented for future work. These are based on surface-specific reactions with glass substrates, and the doping of a regenerated cellulose film with long chain alcohols. On doped cellulose surfaces, some low quantum yields occur compared to clean cellulose and bulk solution. Photobleaching behaviours are also observed. Both dyes physisorb rigidly to cellulose and grease models.
The second part of this thesis identifies the pigment palette of the earliest Northumbrian manuscripts pre- and post-1066, by Raman and diffuse reflectance spectroscopy. It develops a suite of multispectral imaging programs in MATLAB for facile classification of pigments across a page ab initio, using data reduction and colour spaces.
Raman and reflectance data are meta-analysed using symmetric permutation to split manuscripts and pigments into groups ab initio. It was also generalised, that the palette of the pre-Hastings selected manuscripts contained vergaut, indigo, orpiment, impure red lead, and copper green pigments, as well as orcein purples. Immediately post-1066 white lead, red ochre, vermilion and lapis lazuli appear in the palette in England, though vergaut and indigo disappear and the red lead used is essentially pure
The incidence of subsequent contralateral hip fracture and factors associated with increased risk:The IMPACT Contralateral Fracture Study
IntroductionHip fractures are associated with high morbidity and mortality and patients that sustain a subsequent contralateral fracture experience inferior outcomes. The risk of contralateral fracture is highest within the first year, however the incidence and associated factors remain poorly understood. The aims were to investigate i) the incidence of a subsequent contralateral hip fracture within the first year ii) identify factors associated with an increased risk of contralateral fracture, and iii) compare early mortality risk after index versus contralateral hip fracture. MethodsThis study included all patients aged over 50 years admitted to NHS hospitals in Scotland between 1st March 2020 and 31st December 2020 (n=5566) as routine activity of the Scottish Hip Fracture Audit (SHFA). Multivariate logistic regression was used to examine factors associated with 30-day mortality and cox regression was used to identify factors associated with a contralateral fracture. ResultsDuring the study period 2.5% (138/5566) of patients sustained a contralateral hip fracture within 12 months of the index hip fracture. Socioeconomic deprivation was inversely associated with increased risk of contralateral fracture (odds ratio 2.64, p<0.001), whilst advancing age (p=0.427) and sex (p=0.265) were not. After adjusting for significant cofounders there was no significant difference in 30-day mortality following contralateral fracture compared to index fracture (OR 1.22, p=0.433). ConclusionOne in 40 (2.5%) hip fracture patients sustained a contralateral fracture within 12 months of their index fracture and deprivation was associated with a reduced risk of contralateral fracture. No difference in 30-day mortality was found. <br/
Proximal forearm fractures: epidemiology, functional results and predictors of outcome
Proximal forearm fractures account for over 10% of all upper limb fractures. There
is limited epidemiological data available and much of the literature focuses on the
more complex fracture patterns, with the role of non-operative management for the
isolated proximal forearm fracture still to be defined. Prospective short and long-term
patient reported outcome data for simple isolated fractures of the radial head
and olecranon would help define the indications for the non-operative management
of these injuries. This thesis aims to test the hypothesis that non-operative
management provides a comparable outcome to operative intervention for defined
fractures of the proximal forearm.
A large prospective database of 6872 fractures collected over a one-year
period was used to define the epidemiology of proximal forearm fractures. A
separate large prospective study carried out over an eighteen-month period using a
pre-defined management protocol for all isolated radial head and neck fractures was
analysed to determine the short and long-term outcome. Additional retrospective
databases were collected and analysed to determine the short and long-term outcome
for the non-operative and operative management of olecranon fractures, as well as
the operative management of complex radial head fractures. Finally, two prospective
randomised controlled trials (PRCTs) of isolated displaced fractures of the olecranon
were carried out to compare 1) tension band wire (TBW) versus plate fixation in
younger patients (<75 years) and 2) operative versus non-operative management in
elderly patients (≥75 years). The primary outcome measure for these studies was the
upper limb specific patient reported Disabilities of the Arm, Shoulder and Hand
(DASH) score. Secondary outcome measures included surgeon reported outcome
scores, complication rates and cost.
The incidence of proximal forearm fractures was 68 per 100,000. Radial
head fractures fit a type D distribution curve (unimodal young man, bimodal woman)
and radial neck type A (unimodal young man, unimodal older woman). Proximal
ulna and olecranon fractures were both a type F (unimodal older man, unimodal
older woman), with an increasing incidence after the 6th decade. Over 90% of
proximal radial fractures were isolated stable fractures.
Prospective analysis of 201 isolated proximal radius fractures found that the
patient and surgeon reported outcome following primary non-operative management
for Mason type 1 and type 2 (n=185) fractures was excellent in the short and long-term,
with <2% of patients undergoing secondary surgical intervention. At a mean of
10 years post injury (n=100), the mean DASH score was 5.8 and 92% of patients
were satisfied. Factors associated with a poorer short and long-term patient reported
outcome included increasing fracture displacement (≥5mm) and socio-economic
deprivation. Retrospective analysis of 105 acute unstable complex radial head
fractures found that the mean short-term functional outcome was good (mean
Broberg and Morrey Score 80) following radial head replacement. In the long-term
(mean 7 years), 28% of patients required removal or revision of the prosthesis, with
younger patients and silastic implants independent risk factors (both p<0.05).
Retrospective analysis of 36 operatively managed isolated displaced
olecranon fractures found satisfactory short and long-term outcomes, with the
symptomatic metalwork removal rate 47% and the mean DASH 2.5 at a mean of
seven years post injury. In the PRCT of plate (n=34) versus TBW (n=33) fixation,
comparable functional and patient reported outcomes (DASH 8.5 vs 13.5; p=0.252)
were found at one year following injury. Complication rates were significantly
higher in the TBW group (63.3% vs 37.5%; p=0.042), predominantly due to a
significantly higher rate of symptomatic metalwork removal (50.0% vs 21.9%;
p=0.021), resulting in equivocal costs for both techniques (p=0.131). In older lower-demand
patients, short and long-term retrospective analysis found very satisfactory
outcomes following non-operative management of isolated displaced fractures of the
olecranon, with patient satisfaction 91% and no patients requiring surgery for a
symptomatic non-union. The preliminary results of the PRCT of non-operative
(n=8) versus operative (n=11) management demonstrated comparable functional and
patient reported outcomes at all points over the one-year following injury (all
p≥0.05), with a higher rate of complications (81.8% vs 14.3%; p=0.013) and cost
(p=0.01) following surgical intervention.
The association found between fragility and the epidemiology of proximal
forearm fractures highlighted the importance of considering non-operative
management for these injuries. These findings support non-operative management
for isolated stable radial head and neck fractures. For more complex injuries when
radial head replacement is indicated, there is a high rate of removal or revision, with
younger patients most at risk. In younger active patients with an isolated displaced
fracture of the olecranon, TBW and plate fixation provide comparable short-term
results, with TBW fixation as cost effective despite an increased rate of metalwork
removal. In older lower demand patients, this data provides strong evidence for the
non-operative management of isolated displaced olecranon fractures
The incidence of surgical intervention following a suspected scaphoid fracture
Aims: The underlying natural history of suspected scaphoid fractures (SSF) is unclear and assumed poor. There is an urgent requirement to develop the literature around SSFs to quantify the actual prevalence of intervention following SSF. Defining the risk of intervention following SSF may influence the need for widespread surveillance and screening of SSF injuries and could potentially influence medicolegal actions around missed scaphoid fractures.Methods: Data on SSF was retrospectively gathered from Virtual Fracture Clinic (VFC) across a large Scottish Health Board over a four-year period from 1st January 2018 – 31st December 2021. The Bluespier Electronic Patient Record System identified any surgical procedure being undertaken in relation to a scaphoid injury over the same time period. Isolating patients who underwent surgical intervention for SSF was performed by cross referencing the unique patient Community Health Index [CHI] number for patients who underwent these scaphoid procedures with those seen at VFC for SSF over this four-year period.Results: 1739 patients were identified as having had a SSF. Five patients (0.28%) underwent early ORIF. One patient (0.06%) developed a non-union and underwent ORIF with bone grafting. All 6 patients undergoing surgery were male (p=0.0055). The overall rate of intervention following a SSF was 0.35%. The early intervention rate in those undergoing primary MRI was one (0.36%) compared with 3 in those without (0.27%)(p>0.576, Fishers exact test).Conclusions: Surgical intervention was rare following a SSF and was not required in women. A primary MRI policy did not appear be associated with any change in primary or secondary intervention. This data is the first and largest in recent literature to quantify the prevalence of surgical intervention following a SSF and may be used to guide surveillance and screening pathways as well as defining medicolegal risk involved in missing a true fracture in SSFs
The gatekeeper: individual differences are key in the chain from perception to behaviour
A basic assumption in mainstream social cognition is that the path from perception to behaviour is often automatic and direct, as supported for example by several experimental studies showing that priming can lead directly to a congruent behaviour without any need of conscious awareness of the process. However, we argue that the priming of a goal or an object activates individual differences in automatic evaluations at the associative level that in turn are the key predictors of action (gatekeeper model). A study (n = 90) on the American stereotype is presented to support the model. The results show that individual differences of the American stereotype as assessed with the IAT predicts a relevant action (essay evaluation) but only under condition of priming. Broader implications for predictive validity of implicit measures are also discussed
- …