Prediction, detection and suppression of cerebral microemboli associated with carotid disease

Background Transient cerebral microemboli detected by transcranial Doppler (TCD) have been demonstrated to be a reliable biomarker for short term stroke risk in two clinical settings; patients with carotid artery stenosis and those following carotid endarterectomy. Suppressing cerebral microemboli using TCD-directed antiplatelet treatment reduces risk of recurrent stroke. The association between classical cardiovascular risk factors and cerebral microemboli has not been studied. Furthermore, standard TCD method to detect cerebral microemboli is limited by lack of acoustic temporal bone window which is not available in approximately 1 in 7 patients. TCD is the only real-time imaging modality for detecting microemboli. The demonstration of the kinetic of the microemboli is invaluable in assessing the efficacy of antiplatelet agents. Hypotheses 1. Whether Pocock cardiovascular risk score and ABCD2 risk score are able to predict the presence of cerebral microemboli. 2. The feasibility of using transorbital Doppler as an alternative to transcranial Doppler. 3. The effectiveness of Tirofiban in suppressing cerebral microemboli. Methods 1. Pocock score was assessed for the newly developed Carotid Surgery Registry of 670 patients managed between January 2002 and December 2012. 2. ABCD2 score was determined in 206 patients with hyper-acute symptomatic critical carotid artery stenosis in which 102 of these patients were from Registry. A further 104 consecutive patients were recruited between February 2011 and May 2013 within a new prospective observational study. 3. The feasibility of using transorbital Doppler was assessed based on the Registry data. Further new prospective validation study of transorbital Doppler against standard TCD method involving 100 consecutive patients undergoing elective carotid endarterectomies were undertaken. 4. From the Registry, patients who had microembolic signals acutely following carotid surgery were assessed to evaluate the effectiveness of Tirofiban in suppressing microemboli. Findings 1. A high Pocock score (≥ 0.8%) predicts presence of cerebral microemboli acutely following carotid endarterectomy (Area Under Curve (AUC) 0.582 95% CI 0.507 – 0.658, P = 0.038). It also showed a high sensitivity for the presence of microemboli in patients with hyper-acute symptomatic carotid artery disease. 2. The ABCD2 score did not predict presence of cerebral microemboli ((AUC 0.49 95% CI 0.41 – 0.57, P = 0.860), or carotid disease in over one-quarter of patients with symptomatic critical carotid artery stenosis. 3. Transorbital Doppler imaging appears a valid alternative to transcranial Doppler for detecting microembolic signals in patients with no suitable temporal acoustic window (sensitivity 80 %, specificity 86 %. Bland and Altman analysis revealed no significant bias [bias 0.11 microemboli (95% CI: -0.52 to 0.74), P = 0.81]). 4. Tirofiban has been shown to be more effective in treating microemboli in comparison to other most commonly used antithrombotic agents. The time for complete microemboli resolution (Tirofiban 68 minutes (53-94); dextran 113 (79-146); or in controls 53(49-68); P<0.001, KW) were shorter with tirofiban

ABCD² risk score does not predict the presence of cerebral microemboli in patients with hyper-acute symptomatic critical carotid artery stenosis

ABCD² risk score and cerebral microemboli detected by transcranial Doppler (TCD) have been separately shown to the predict risk of recurrent acute stroke. We studied whether ABCD² risk score predicts cerebral microemboli in patients with hyper-acute symptomatic carotid artery stenosis. We studied 206 patients presenting within 2 weeks of transient ischaemic attack or minor stroke and found to have critical carotid artery stenosis (≥50%). 86 patients (age 70±1 (SEM: years), 58 men, 83 Caucasian) had evidence of microemboli; 72 (84%) of these underwent carotid endarterectomy (CEA). 120 patients (age 72±1 years, 91 men, 113 Caucasian) did not have microemboli detected; 102 (85%) of these underwent CEA. Data were analysed using X2 and Mann-Whitney U tests and receiver operating characteristic (ROC) curves. 140/206 (68%: 95% CI 61.63 to 74.37) patients with hyper-acute symptomatic critical carotid stenosis had an ABCD2 risk score ≥4. There was no significant difference in the NICE red flag criterion for early assessment (ABCD² risk score ≥4) for patients with cerebral microemboli versus those without microemboli (59/86 vs 81/120 patients: OR 1.05 ABCD² risk score ≥4 (95% CI 0.58 to 1.90, p=0.867)). The ABCD² risk score was <4 in 27 of 86 (31%: 95% CI 21 to 41) embolising patients and in 39 of 120 (31%: 95% CI 23 to 39) without cerebral microemboli. After adjusting for pre-neurological event antiplatelet treatment (APT), area under the curve (AUC) of ROC for ABCD2 risk score showed no prediction of cerebral microemboli (no pre-event APT, n=57: AUC 0.45 (95% CI 0.29 to 0.60, p=0.531); pre-event APT, n=147: AUC 0.51 (95% CI 0.42 to 0.60, p=0.804)). The ABCD² score did not predict the presence of cerebral microemboli or carotid disease in over one-quarter of patients with symptomatic critical carotid artery stenosis. On the basis of NICE guidelines (refer early if ABCD² ≥4), assessment of high stroke risk based on ABCD² scoring may lead to inappropriate delay in urgent treatment in many patients

Sustainable waste management via incineration system: an Islamic outlook for conservation of the environment

This paper would firstly examine solid waste management currently experienced in Malaysia with special concentration given to waste incineration. Its function and benefits entailed from this system shall then be identified. This paper attempts to emphasize this notion within the Islamic perspective, stressing on the needs to conserve the environment. This study adopts a qualitative approach where the conceptual authoritative literature in the related field is utilized based on content analysis. The related principles of Islamic jurisprudencecarefully examined along with the Quranic verses depicting on this issue This study further submits that incinerating waste could mitigate environmental impact that might otherwise arise from waste. Finally, it further concludes that Islam provides a concrete model of environmental ethics which is based on divine revelation that needs to be observed.Keywords: sustainable waste management; incineration system; environment conservation;Islamic jurisprudence principles

Parameter optimization of debinding injection moulded Ti-6Al-4V mix with palm stearin and polyethylene

Debinding process of injection moulded Ti-6Al-4V feedstock was divided into two parts: solvent debinding process to eliminate palm stearin (PS) and thermal pyrolysis to eliminate polyethylene (PE). Solvent debinding process used heptane at optimum temperature, 60°C to remove PS binder completely as temperature is the only parameter that can be optimized. Thermal pyrolysis parameters for removal of PE binder from the injected 65vol% Ti-6Al-4V feedstock have been optimized by using Taguchi method. Heating rate, temperature and time were the selected factors during experiment to be applied in the L9(34) Taguchi orthogonal array (OA) to find the best set of parameters to produce highest density of brown part. Thermal pyrolysis process was done at optimum parameters: heating rate: 5°C/min; temperature: 510°C; and time: 90 minutes. Analysis of Variance (ANOVA) was employed to find the best signal to noise ratio (S/N) to express the contribution of the factors towards quality characteristic. Based on the results, heating rate has the greatest contribution (54.63%), followed by duration time of thermal pyrolysis (24.40%) and temperature (19.25%)

The analysis of grid independence study in continuous disperse of MQL delivery system

A sustainable cutting method of Minimum Quantity Lubricant (MQL) was introduced to promote lubrication effect and improve machinability. However, its performances are very dependent on the effectiveness of its mist to penetrate deep into the cutting zone. Optimizing the MQL system requires massive experimental work that increases cost and time. Therefore, this study conducts Computational Fluid Dynamic (CFD) analysis using ANSYS Fluent and focuses on the grid independence study in dispersed-continuous phase of MQL delivery system. The main aim is to identify the best mesh model that influences the accuracy of the CFD model. The analysis proposed two different unstructured grid cell elements of quadrilateral and triangular that were only applicable for 2-dimensional fluid flow in CFD. The unstructured grid was controlled with three different mesh quality factors such as Relevance Center, Smoothing, and Span Angle Center at coarse /low, medium, and fine /high. The results showed that the best mesh quality for quadrilateral was at 60,000 nodes number and coarse mesh, whereas the triangular was at 90,000 nodes number and coarse mesh. Both combinations resulted the most consistent and reliable result when compared with past studies. However, this study decided to choose quadrilateral cell element with 60,000 nodes number and coarse mesh as it is considered to be sufficient to provide accurate and reliable result as well as practical in terms of computational time for the MQL model in CFD analysis

Prediction of Cutting Force in End Milling of Inconel 718

This paper presents the effect of cutting parameters on the cutting force when machining Inconel 718. Response surface methodology (RSM) was used in the experiment, and a Box–Behnken design was employed to identify the cause and effect of the relationship between the four cutting parameters (cutting speed, feed rate, depth of cut and width of cut) and cutting force. The ball-nose type of end mill with donwmill approach was maitained througout the experiment. The forces were measured using Kistler dynamometer during straight line machining strategy. The result shows that the radial depth of cut was the dominating factor controlling cutting force, it was followed by axial depth of cut and feed rate. The prediction cutting force model was developed with the average error between the predicted and actual cutting force was less than 3

Individually-tailored multifactorial intervention to reduce falls in the Malaysian Falls Assessment and Intervention Trial (MyFAIT): A randomized controlled trial

Objective: To determine the effectiveness of an individually-tailored multifactorial intervention in reducing falls among at risk older adult fallers in a multi-ethnic, middle-income nation in South-East Asia. Design: Pragmatic, randomized-controlled trial. Setting: Emergency room, medical outpatient and primary care clinic in a teaching hospital in Kuala Lumpur, Malaysia. Participants: Individuals aged 65 years and above with two or more falls or one injurious fall in the past 12 months. Intervention: Individually-tailored interventions, included a modified Otago exercise programme, HOMEFAST home hazards modification, visual intervention, cardiovascular intervention, medication review and falls education, was compared against a control group involving conventional treatment. Primary and secondary outcome measures: The primary outcome was any fall recurrence at 12-month follow-up. Secondary outcomes were rate of fall and time to first fall. Results: Two hundred and sixty-eight participants (mean age 75.3 ±7.2 SD years, 67% women) were randomized to multifactorial intervention (n = 134) or convention treatment (n = 134). All participants in the intervention group received medication review and falls education, 92 (68%) were prescribed Otago exercises, 86 (64%) visual intervention, 64 (47%) home hazards modification and 51 (38%) cardiovascular intervention. Fall recurrence did not differ between intervention and control groups at 12-months [Risk Ratio, RR = 1.037 (95% CI 0.613–1.753)]. Rate of fall [RR = 1.155 (95% CI 0.846–1.576], time to first fall [Hazard Ratio, HR = 0.948 (95% CI 0.782–1.522)] and mortality rate [RR = 0.896 (95% CI 0.335–2.400)] did not differ between groups. Conclusion: Individually-tailored multifactorial intervention was ineffective as a strategy to reduce falls. Future research efforts are now required to develop culturally-appropriate and affordable methods of addressing this increasingly prominent public health issue in middle-income nations

Giant Merkel cell carcinoma of the eyelid: a case report and review of the literature

Merkel cell carcinoma (MCC) is a rare cutaneous tumor and cases located in the eyelid have been described, but still its rarity may lead to difficulty in diagnosis and delay in treatment. A 51-year-old female patient that presented with large lesions in the eyelid underwent surgery after the diagnosis of acute chalazion. Following respiratory distress secondary to pulmonary metastasis, the patient's condition deteriorated and was not fit for complete excision treatment. Histopathological investigation of the biopsies, taken from the tumor, revealed that it was undifferentiated small cell carcinoma. Our aim with this paper is to point out that more cases should be reported for more effective diagnosis, histopathological study, clinical investigation, treatment and prognosis of this specific neoplasm

The national portfolio for postgraduate family medicine training in South Africa : a descriptive study of acceptability, educational impact, and usefulness for assessment

Background: Since 2007 a portfolio of learning has become a requirement for assessment of postgraduate family medicine training by the Colleges of Medicine of South Africa. A uniform portfolio of learning has been developed and content validity established among the eight postgraduate programmes. The aim of this study was to investigate the portfolio's acceptability, educational impact, and perceived usefulness for assessment of competence. Methods: Two structured questionnaires of 35 closed and open-ended questions were delivered to 53 family physician supervisors and 48 registrars who had used the portfolio. Categorical and nominal/ordinal data were analysed using simple descriptive statistics. The open-ended questions were analysed with ATLAS.ti software. Results: Half of registrars did not find the portfolio clear, practical or feasible. Workshops on portfolio use, learning, and supervision were supported, and brief dedicated time daily for reflection and writing. Most supervisors felt the portfolio reflected an accurate picture of learning, but just over half of registrars agreed. While the portfolio helped with reflection on learning, participants were less convinced about how it helped them plan further learning. Supervisors graded most rotations, suggesting understanding the summative aspect, while only 61% of registrars reflected on rotations, suggesting the formative aspects are not yet optimally utilised. Poor feedback, the need for protected academic time, and pressure of service delivery impacting negatively on learning. Conclusion: This first introduction of a national portfolio for postgraduate training in family medicine in South Africa faces challenges similar to those in other countries. Acceptability of the portfolio relates to a clear purpose and guide, flexible format with tools available in the workplace, and appreciating the changing educational environment from university-based to national assessments. The role of the supervisor in direct observations of the registrar and dedicated educational meetings, giving feedback and support, cannot be overemphasized