28 research outputs found

    An Effective Method for the Preparation of High Temperature Stable Anatase TiO2 Photocatalysts

    Get PDF
    An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH4F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO2: NH4F at 1200 °C was seen to be most effective, having stable anatase present at 57.1 % compared to undoped TiO2 being 100 % rutile from 900 °C. This method involves the production of ammonium oxofluorotitanates (NH4TiOF3) at low temperatures. The inclusion of these intermediates greatly reduces the particle size growth and delays the anatase to rutile transition. The photocatalytic activity of these materials was studied by analysing the degradation of an organic dye, rhodamine 6G as a model system and the rate constant was calculated by pseudo-first-order kinetics. These results showed that the doped sample (0.0225 min-1) was three times more active than the undoped sample (0.0076 min-1) and over seven times faster than the commercial TiO2 photocatalyst standard Degussa P-25 calcined at 1200 °C (0.0030 min-1). The formation of intermediate compounds, oxofluorotitanates, was identified as the major reason for a delay in the anatase to rutile transition

    An Effective Method for the Preparation of High Temperature Stable Anatase TiO2 Photocatalysts

    Get PDF
    An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH4F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO2: NH4F at 1200 °C was seen to be most effective, having stable anatase present at 57.1 % compared to undoped TiO2 being 100 % rutile from 900 °C. This method involves the production of ammonium oxofluorotitanates (NH4TiOF3) at low temperatures. The inclusion of these intermediates greatly reduces the particle size growth and delays the anatase to rutile transition. The photocatalytic activity of these materials was studied by analysing the degradation of an organic dye, rhodamine 6G as a model system and the rate constant was calculated by pseudo-first-order kinetics. These results showed that the doped sample (0.0225 min-1) was three times more active than the undoped sample (0.0076 min-1) and over seven times faster than the commercial TiO2 photocatalyst standard Degussa P-25 calcined at 1200 °C (0.0030 min-1). The formation of intermediate compounds, oxofluorotitanates, was identified as the major reason for a delay in the anatase to rutile transition

    Outcome of periacetabular osteotomy for the management of acetabular dysplasia: experience in an academic centre.

    Get PDF
    Periacetabular osteotomy (PAO) is a very effective reconstructive procedure for treatment of acetabular dysplasia. An orthopaedic paediatric surgeon and a reconstructive hip arthroplasty surgeon performed this procedure together in the early phase of their learning curve and then performed it individually. The early clinical and radiographic results of 85 consecutive PAOs performed in this academic orthopaedic unit were reviewed. The mean Merle-d\u27Aubigné score increased from 12.4 preoperatively to 16 at follow-up. Pre-operatively 73 hips were anteverted and 12 were neutral or retroverted. The mean angle of Wiberg improved from 5 degrees to 21 degrees (p \u3c 0.0001) in anteverted hips, and from 9 degrees to 30 degrees in neutral or retroverted hips. The mean angle of Lequesne and de Sèze improved from 6 degrees to 35 degrees (p \u3c 0.0001) in anteverted hips, and in neutral or retroverted hips from 9 degrees to 30 degrees (p \u3c 0.0001). The acetabular index improved from 26 degrees to 8 degrees (p \u3c 0.0001) in anteverted hips, and from 21 degrees to 7 degrees (p \u3c 0.0001) in neutral or retroverted hips. Over the 7 year period the blood loss and operative time improved from 2000 ml to 900 ml and 4 hours to 2 hours respectively. Four hips (four patients) required conversion to total hip replacement. The radiographic correction and improved clinical scores are similar to those in previous studies. This study shows a survival rate of 94% at 58 months following periacetabular osteotomy. The learning curve and the early results of this procedure performed in our academic unit are encouraging

    Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

    Get PDF
    : The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

    Women's group mentoring programs: Chit chat or effective professional development?

    No full text
    Mentoring is widely recognised in the literature as a valuable professional development strategy. However, in today’s higher education context there is a tension between the ideals and values of mentoring and the demands of the ‘corporate’ university for quantifiable outcomes. On-going evaluation of the Women’s Group Mentoring Program at the University of Canberra suggests that this program has successfully negotiated these tensions to dispel the initial perceptions of many workplace supervisors that the program was ‘just a women’s chit chat session’. This presentation will outline the background to the program’s development, describe the program components and examine the benefits identified by participants, their workplace supervisors and program facilitators. These benefits include the formation of both formal and informal university-wide networks for participants which remain functional beyond the end of the Program, a sense of increased connectedness and commitment to the University, skill and knowledge acquisition and career progression, increased self-confidence and the dismantling of myths about academic and general staff roles and responsibilities. The presentation will then draw from this discussion factors that affect the success of such a program and conclude with the implications for others wishing to enhance the career development and leadership potential of women in other higher education contexts

    Acute shortness of breath due to reoccurrence of an intrapericardial bronchogenic cyst

    No full text
    A 71‐year‐old woman presented with dysphagia and acute shortness of breath. Surgical history included a prior thoracotomy overseas for a bronchogenic mesothelial cyst 19 years before. Computed tomography demonstrated a mass within the posterior mediastinum measuring 69 × 70 × 74 mm. A median sternotomy was performed, and after removal of the cyst, repair of the left atrium and pulmonary vessels was undertaken due to the invading nature of the cyst. Intrapericardial bronchogenic cysts are a rare form of congenital cysts arising from the primitive foregut. The cardiac primordia are in close proximity to the foregut and primitive tracheobronchial tree, and thus, abnormal budding of the tracheobronchial tree can arise in a myocardial location. Irrespective of the method of approach in redo surgery, complete resection must be performed in order to minimize the chance of recurrence, relieve symptoms, eliminate risk of infection, and prevent malignant degeneration

    Reliability and concurrent validity of knee angle measurement: smart phone app versus universal goniometer used by experienced and novice clinicians

    Get PDF
    The use of goniometers to measure joint angles is a key part of musculoskeletal practice. Recently smartphone goniometry applications have become available to clinicians. This study examined the intra- and inter-measurer reliability of novice and experienced clinicians and the concurrent validity of assessing knee range of motion using a smartphone application (the Knee Goniometer App (Ockendon©)) (KGA) and a standard universal goniometer (UG). Three clinicians, each with over seven years' experience as musculoskeletal physiotherapists and three final year physiotherapy students, measured 18 different knee joint angles three times, using both the universal goniometer and the smartphone goniometric application. The universal goniometer and the smartphone goniometric application were reliable in repeated measures of knee flexion angles (average Concordance Correlation Coefficient (CCC) > 0.98) with both experienced clinicians and final year physiotherapy students (average CCCs > 0.96). There were no significant differences in reliability between the experienced and the novice practitioners for either device. Agreement between the universal goniometer and smartphone goniometric application measurements was also high for all examiners with average CCCs all above 0.96. The Standard Error of Measurement ranged between 1.56° (0.52e2.66) for the UG and 0.62° (0.29e1.27) for the KGA. The universal goniometer and the smartphone goniometric application were reliable in repeated measures of knee flexion angles. Smaller error of measurement values for the smartphone goniometric application might indicate superiority for assessment where clinical situations demand greater precision of knee range of motion
    corecore