Lee were responsible for the conception and design of the work. Andee Dzulkarnaen, Zaidi Zakaria, Nazri Mustaffa, and Sharifah Emilia Tuan Sharif were involved in sample acquisition and processing. All authors performed the data analysis and interpretation. Yusof Shuaib Ibrahim, Nazri Mustaffa, and Yeong Yeh Lee wrote the manuscript and all authors approved the final version.
Foaming temperature and grade of dry natural rubber were varied to evaluate their effects on the morphology and mechanical properties of natural rubber (NR) foams. Three different grades of NR were used; namely ENR-25, SMR-L, and SMR-10. NR foams from these grades were produced at three different foaming temperatures, i.e. 140, 150, and 1608C. The study was carried out using formulated compositions containing sodium bicarbonate as the chemical blowing agent and were expanded using conventional compression molding technique via a heat transfer foaming process. The NR foams were characterized with respect to their relative foam density, density of crosslinking, cell size, compression stress, and compression set. Increase in foaming temperature resulted in lower relative density and larger cell size.It was also discovered that the crosslink density slightly decrease with increasing foaming temperature. For mechanical properties, the highest foam density resulted in the highest compression stress. Compression stress at 50% strain increased with increasing foaming temperature and ENR-25 foam has the highest compression stress among the produced foams. The results showed that the morphology, physical, and mechanical properties of the rubber foams can be controlled closely by the foaming temperature and rubber grades.
Abstract. The present study focuses on the development and characterization of epoxy syntactic foam filled with epoxy hollow spheres (ESF/EHoS). The epoxy syntactic foam (ESF) was produced by embedding epoxy hollow spheres (EHoS) into a mixture of epoxy-hardener and 3% KOH solution. An innovative approach and simple procedure was implemented in the preparation of the EHoS where expanded polystyrene (EPS) beads were used as initiation material. The EPS beads were coated with the epoxy resin and these coated EPS beads were later cured and post-cured at high temperature which will also shrink the EPS beads thus producing a hollow structure. The physical and compressive properties of the developed ESF were characterized. The progressive collapse of the syntactic foam was monitored in real-time with respect to percentage of strain during a compression test. Results also indicated that the (ESF/EHoS) showed similar deformation pattern with other types of syntactic foams which exhibited the common three regions of deformations.
Biliary ascariasis is a rare disease in a non-endemic area. However, it is one of the possible etiological factors for retarded growth as well as malnutrition in children. It may cause intestinal obstruction, appendicitis, biliary obstruction, liver abscess, hepatolithiasis, and pancreatitis in adults. Herein, we report a patient with ascending cholangitis secondary to biliary ascariasis who was successfully managed with Endoscopic Retrograde Cholangio Pancreaticography.
PurposePatients with secondary hyperparathyroidism are at high risk for developing postoperative hypocalcemia. However, there are limited data regarding predictors of postoperative hypocalcemia in renal failure patient with secondary hyperparathyroidism. This study aimed to determine the clinical presentations of renal hyperparathyroidism and the predictors of early postoperative hypocalcemia after total parathyroidectomy.MethodsData of patients with renal hyperparathyroidism who underwent total parathyroidectomy between January 2007 to December 2014 were reviewed retrospectively. Patients were divided into 2 cohort groups according to their serum calcium levels within 24 hours of parathyroidectomy: the hypocalcemia group (calcium levels of 2 mmol/L or less), and the normocalcemia group (calcium levels more than 2 mmol/L). With the use of multivariable logistic regression analyses, the predictors of early postoperative hypocalcemia after total parathyroidectomy in patients with renal hyperparathyroidism were investigated.ResultsAmong 68 patients, 56 patients (82.4%) were symptomatic preoperatively. Fifty patients (73.5%) presented with bone pain and 14 patients (20.6%) had muscle weakness. Early postoperative hypocalcemia occurred in 25 patients (36.8%). Preoperative alkaline phosphatase level was the predictor of early postoperative hypocalcemia (adjusted odds ratio, 1.004; 95% confidence interval, 1.001–1.006; P = 0.002).ConclusionResults from our study show that most of the patients with renal hyperparathyroidism were symptomatic preoperatively and the most common clinical presentations were bone pain and muscle weakness. The significant predictor of early postoperative hypocalcemia after total parathyroidectomy was the preoperative alkaline phosphatase levels.
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