Dispersion of positron emitting radioactive gases in a complex urban building array: a comparison of dose modelling approaches.

A radiological assessment was carried out on the release of positron-emitting radioactive gases from a roof-level stack at a central London site. Different modelling approaches were performed to investigate the range of radiation doses to representative persons. Contributions from plume inhalation, gamma shine and immersion to effective dose were taken into account. Dry and wet surface deposition on the roof, and exposure from contamination on the skin of roof-workers, added only a mean 4.7% to effective dose and were neglected. A 1:200 scale model, consisting of the stack and surrounding buildings, was tested in a wind tunnel to simulate pollutant dispersion in the near-field region i.e. rooftop. Concentration field measurements in the wind tunnel were converted into effective dose, including for roof-workers installing glass cladding to the stack building. Changes in the building shape, from addition of the cladding layer, were investigated in terms of the near-field flow pattern and significant differences found between the two cases. Pollutant concentrations were also modelled using Air Dispersion Modelling System (ADMS) and the results used to calculate the effective dose using the same meteorological data set and source release terms. Sector averaged wind tunnel dose estimates were greater than the ADMS figure by approximately a factor of two to three. Different stack release heights were investigated in the wind tunnel and ADMS simulations in order to determine the best height for the replacement flue stack for the building. Other techniques were investigated: building wake models, modified Gaussian plume methods and uniform dilution into a hemispherical volume to show the wide variation in predicted dose possible with different approaches. Large differences found between simpler analytic approaches indicated that more robust radiological assessments, based on more complex modelling approaches, were required to achieve satisfactory estimates of radiation dose to representative groups in adjacent buildings and on the building rooftop.

The reliability of character recognition: An Australian & New Zealand expert-novice comparison study in the interpretation of chemically recovered serial numbers.

The chemical recovery of a defaced serial number is a common forensic science practice, however it is not understood how proficient experts perform in correctly identifying recovered serial numbers. Understanding the accuracy of experts and how they compare to novices in character recognition can help to establish a baseline for this expertise. In this study an expert-novice comparison assessment was completed involving 118 test plates, each stamped with six randomised alphanumeric characters. The plates were defaced and chemically recovered before being viewed by multiple participants over six time intervals. A total of 3169 character inspections were completed. An assessment of confidence and error rates were calculated for both expert (trained) and novice (untrained) participants. Errors were counted when a participant interpreted a different character to that of the ground truth and believed the result was accurate for reporting. The results showed a similar (2.3 % and 2.4 %) error rate for the cohorts, however a statistical difference in confidence levels was recorded, demonstrating the more conservative nature of experts. This study aims to assist in validating practitioner interpretations, through addressing some forensic science criticisms, such as establishing error rates to routine scientific practices.

Preoperative neutrophil to lymphocyte ratio >5 is a prognostic factor for recurrent colorectal cancer.

AIM: Previous studies have demonstrated that raised preoperative neutrophil to lymphocyte ratio (NLR) is associated with poor prognosis in colorectal cancer (CRC). The aim of this study was to assess whether preoperative NLR could predict patients at risk of recurrence of CRC. METHOD: All consecutive patients who underwent surgical resection for CRC over a 2-year period at our institution were analysed. Demographic data including CRC recurrence were prospectively collected from our institutional cancer database. CRC recurrence was diagnosed on radiological and endoscopic histopathological data. Preoperative NLR was calculated on baseline blood results, with a value >5 being a poor prognostic factor. Parametric survival analysis was used to identify risk factors for CRC recurrence. Hazard ratios (HRs) were calculated for gender, CRC stage using Jass score, preoperative NLR and CRC site. P < 0.05 was considered statistically significant. RESULTS: In all, 297 patients (157 men) underwent CRC resection at a median age of 70 years (range 23-93); 164 patients had colon cancer, 111 rectal cancer and 22 recto-sigmoid cancer. The distribution by stage of CRC was 30.2% for stage 1, 23.8% for stage 2, 19.5% for stage 3 and 26.5% for stage 4. Over a median follow-up period of 3.35 (0.1-8) years, 59 (19.8%) patients had recurrent CRC. Multivariate analysis revealed CRC stage (HR 8.69, 95% CI 3.85-19.6, P < 0.0001) and NLR >5 (HR 1.81, 95% CI 1.07-3.07, P = 0.028) to be significant and independent risk factors predictive of recurrent CRC. CONCLUSION: These data suggest that preoperative NLR >5 is predictive of CRC recurrence.

Problem-based learning in postgraduate dental education: a qualitative evaluation of students' experience of an orthodontic problem-based postgraduate programme.

INTRODUCTION: Problem based learning (PBL) has gained wide acceptance in undergraduate education, but less so in postgraduate education. Qualitative research methodologies can help us gain insight and understanding of the students' experience in undertaking such programmes. AIM: To evaluate the experiences of postgraduate students undertaking a PBL based postgraduate programme. METHODS: Focus groups and semi-structured interviews were used to investigate students' experiences. The qualitative data were coded, the codes were grouped into categories and a coding framework developed. From this a construct is proposed to give insight into students' experiences. The validity of this construct was examined by reviewing the literature. RESULTS: Students entered the programme with high expectations, but soon found they had challenges to overcome. They came to realise that they were on a journey, rather than undertaking a sequence of separate individual learning events. PBL led to significant tensions both within the individuals and the group, caused by the conflict between appreciating PBL as a 'good thing' and yet finding that ;it just doesn't seem to work'. The fear of failure in a high stakes setting only exacerbated these tensions. The literature review revealed an inconsistent approach to the use of PBL and its evaluation in a postgraduate/continuing medical education setting. However it did provide evidence of similar findings in qualitative studies, supporting the construct developed. CONCLUSION: We have proposed a construct to help in understanding the PBL experience for students undergoing a 'high stakes' orthodontic postgraduate programme with a core of PBL.

The use of venous anastomotic flow couplers to monitor buried free DIEP flap reconstructions following nipple-sparing mastectomy.

Nipple sparing mastectomy with free tissue transfer for breast reconstruction offers excellent aesthetic outcomes but poses a challenge in monitoring the buried flap. Venous anastomotic flow couplers directly monitor buried flaps without the need for monitoring skin paddles. In a two year period we used the Synovis GEM™ flow coupler on 24 DIEP flaps. In our practice, flow couplers are effective in monitoring buried free flaps for breast reconstruction. The avoidance of a second procedure to remove a skin paddle improves patient experience and nullifies the additional flow coupler cost. One patient needed return to theatre when a Doppler wire became dislodged early in the series. There were no other issues with flap monitoring and no flap failures. We offer our tips to optimise flow coupler use.

The use of a failed flap as a biological dressing.

A patient with a narrowly excised squamous cell carcinoma on the scalp underwent a wider excision that involved burring of the underlying calvarium. The defect was reconstructed with a superficial temporal artery pedicled flap, which unfortunately failed. The patient had multiple co-morbidities, limiting reconstructive options. The failed flap was therefore maintained as a 'biological dressing' for several weeks. During this time, the patient was reviewed regularly in the dressing clinic and did not develop a wound infection. Six weeks later, he was taken back to theatre and the flap was debrided under local anaesthesia. Beneath the flap, there was sufficient healthy granulation tissue over the site of previous bony debridement to permit split skin grafting. We advocate this technique as a useful method for managing difficult wounds in complex patients with multiple co-morbidities where other reconstructive techniques are limited.

Diagnosis of testicular torsion using Doppler ultrasonic flowmeter.

Thirty-one patients with intrascrotal disease process have been studied with the Doppler ultrasonic flowmeter to determine if testicular torsion can be differentiated from acute epididymitis when clinical characteristics are ambivalent. In all instances of proved torsion there was a loss of blood flow in the involved testes, whereas in acute epididymitis or other epididymal and gonadal diseases blood flow ranged from normal to hyperemic.

Biliary sludge: can ultrasound reliably detect the presence of crystals in bile?

OBJECTIVE: To determine the accuracy of routine gallbladder ultrasound in the detection of crystals in bile. METHODS: Preoperative ultrasonography was performed in 40 patients undergoing elective cholecystectomy. Bile was aspirated at operation and examined microscopically for the presence and quantity of crystals. RESULTS: Six patients had echogenic bile, five of whom had large numbers of crystals at microscopy, and one only a few crystals. Thirty-four patients had hypoechoic bile, nine had large numbers of crystals and 25 of these had few or no crystals at microscopy. For those patients with echogenic bile (hyper- or isoechoic) the sensitivity for detection of large numbers of crystals was 5/14 (35.7%) with a specificity of 25/26 (96%). However, if the bile was hypoechoic the sensitivity was 9/14 (65%). CONCLUSION: For those patients with echogenic bile, ultrasound is highly specific for the detection of crystals, although the sensitivity is low. By contrast, those patients with hypoechoic bile at ultrasound would need a further investigation to exclude the presence of crystals.

Can serum interleukin-6 levels predict the outcome of patients with right iliac fossa pain?

In patients with right iliac fossa (RIF) pain it can be difficult to distinguish between appendicitis and nonspecific abdominal pain (NSAP). In this study we sought to determine whether serum interleukin-6 (IL-6) levels, an early marker of acute inflammation, taken at the time of admission could predict the outcome of patients admitted with RIF pain. Data were collected in a prospective manner on 53 consecutive patients (23 male, 30 female), mean age 22.1 years (range 10-79 years). Nineteen (36%) patients underwent surgery, of whom 16 had appendicitis (histologically proven). The mean (SEM) IL-6 levels (pg/ml) in patients undergoing operation vs those receiving non-operative management were 270.8 (106.3) vs 265.0 (80.4) (P = NS). The mean white blood cell (WBC) counts (x10(9)/l) in these patients were 14.28 (0.81) vs 9.66 (0.67), respectively (P = 0.0002). When patients with a confirmed diagnosis of appendicitis were compared with patients with a diagnosis of NSAP, the IL-6 levels were 149.4 (69.1) vs 363.6 (113.2), respectively (P = NS). In the same groups of patients, the WBC counts were 14.21 (0.81) vs 9.51 (0.68) (P = 0.004). We conclude that IL-6 levels taken at the time of admission are not useful in predicting the outcome of RIF pain.

Percutaneous endovascular covered stenting of a distal superficial femoral artery occlusion.

Peripheral vascular disease is a common problem in the elderly population. This is commonly treated nowadays by percutaneous transluminal angioplasty (PTA). When PTA is used in the treatment of superficial femoral artery (SFA) occlusions 35% reocclude within 1 year. Endovascular stents (uncovered) have been used to try to overcome this problem; however, results have been disappointing with reocclusion rates similar to PTA. In order to try to reduce this problem covered endovascular stents have been developed. We report the first known case in the UK of one of these stents being used in the treatment of SFA disease.

Initial experience of 3-D video endoscopy in general surgery.

The worldwide explosion of Iaparoscopic surgery within general surgery began in the late 1980sand early 1990s.From its inception, surgeons have expected the image on the video monitor to resemble closely the . image obtained in similar open surgery.The monitor image, however, is presented in two dimensions- height and width. Orientation of the surgeon to the anatomy is more difficult and requires a sound knowl- edge of anatomy, the relationships of organs to each other, and an understanding of the individual patient's unique structures. Adding a third dimension, depth, to imitate natural vision in open surgery may provide surgeons with the confidence to perform more advanced procedures. In addition, trainee surgeons, without the experience of open surgery which their senior colleagues have gained, may more rapidly appreciate orientation of the anatomy and learn the surgical task more quickly.

Hypothermia and the use of space blankets: a literature review.

Developed in the 1960s, the 'space blanket' subsequently became a popular tool in the management of the hypothermic patient. Recent articles addressing the issue of the management of hypothermia have tended to offer a variety of suggestions for combating hypothermia, but mention of the space blanket as a tool in this aim appears to have diminished. A review of 20 articles concerned with the management of hypothermia (and identified using a computerized search strategy) indicates that the space blanket has fallen from popularity in treating hypothermic patients and supports the notion that A & E departments should employ alternative methods for rewarming the patient with hypothermia.

The first 100 cases of orthodontic treatment: one year out of retention.

The Index of Orthodontic Treatment Need (IOTN) and Peer Assessment Rating (PAR) Index have been developed to assess need and outcome of orthodontic treatment. In this paper the authors evaluate the occlusal change and orthodontic treatment need of 100 consecutively started courses of orthodontic treatment at least 1 year after all retention measures had ceased using these indices.

The use of myofunctional appliances in the UK: a survey of British orthodontists.

A questionnaire was sent out to members of the British Orthodontic Society in an attempt to establish how myofunctional appliances are currently used in the UK and to attempt to explain the differences between provider groups. This article reports the findings of this survey and that, of all the appliances currently available, British orthodontists prefer to use the Twin Block appliance. Furthermore, most of the sample questioned felt that the laboratory cost of many myofunctional appliances meant their provision under the General Dental Service was not practical.

Event related outdating: a fairy tale comes true.

Traditionally ORs and CSRs have outdated reusable sterile goods at predetermined times. Professional standards (ORNAC, AORN, CSA) support event related outdating meaning that sterile goods remain sterile indefinitely unless package integrity is compromised. Significant savings in supply and labour costs can be realized without compromising patient care. The article outlines a model for the implementation of event related outdating.

Thirteen Patients with MAT1A Mutations Detected Through Newborn Screening: 13 Years' Experience.

BACKGROUND: Methionine adenosyltransferase I/III (MATI/III) deficiency is the most common genetic cause of persistent isolated hypermethioninemia. Patients and Methods : This is a retrospective data analysis of 62 newborns with elevated methionine detected by newborn screening between January 2000 and June 2013. The clinical, biochemical, and molecular findings of a subset of these children with MAT1A mutations associated with MATI/III deficiency are presented. RESULTS: Of the 62 newborns with elevated methionine, 12 were identified as having classical homocystinuria; 37 were false-positives; and 13 were found to have isolated persistent hypermethioninemia in the absence of biochemical markers of homocystinuria, abnormal liver function studies, or other causes of elevated methionine. These 13 individuals underwent genetic testing for changes in the MAT1A gene, associated with MATI/III deficiency. Three of 13 were found to have the common autosomal dominant R264H mutation, one was found to be a compound heterozygote for two novel pathogenic mutations, and three were found to be heterozygotes for previously reported mutations shown to cause autosomal recessive MATI/III deficiency when present in homozygous or a compound heterozygous configuration. The remaining six patients had variants of unknown clinical significance or novel mutations. For the majority of individuals, methionine persisted above the normal range but trended downward over time. None of these 13 individuals was started on a low-methionine diet, and all have age-appropriate growth and development. CONCLUSION: These cases show that individuals with even single changes in the MAT1A gene may have elevations in methionine identified by newborn screening, which may persist for months after birth without any clinical consequences.

Susuk charms? A case report.

This case report describes an interesting incidental finding on an orthopantomogram: bilateral radio-opaque objects in the mandibular rami region. The origin of the objects remains unidentified; however, the authors have tentatively identified these as being susuk by a process of exclusion of other possibilities.

The relation of experience in osteopathic palpation and object identification.

BACKGROUND: To determine whether osteopathic medical students, fellows, residents, and practicing physicians differ in their ability to identify inanimate objects and if these skills relate to palpatory experience. METHODS: Fifteen commonly known objects were fixed to a board and blinded with a cotton cloth. In Part I of testing, participants were asked to identify 9 objects, with choices provided. In Part II participants were asked to identify 6 objects using one word only. Part III consisted of identifying the shape of an object in Part II. RESULTS: Eighty-nine osteopathic medical students, fellows, residents, and practicing physicians participated in the study. Overall, correct identification of objects was higher in Part I with choices than in Part II without choices available. No statistically significant difference was found among osteopathic medical students, fellows, residents, and practicing physicians in the correct identification of the objects. CONCLUSIONS: Accuracy in tactile identification of objects among varying levels of palpatory experience was not found. Correlation with clinical palpation cannot be made as it requires a subset of palpatory skills not tested in this study. Accuracy and measurement of palpation should be studied further to demonstrate if palpatory experience improves palpatory accuracy.