19672 research outputs found
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Comparative study on using static and dynamic finite element models to develop FWD measurement on flexible pavement structures
No full textThe deflection basin obtained through backcalculation analysis is compared with the measured deflection basin to determine the moduli of each pavement layer. Most computer programs use multi-layered elastic theory (MET) to perform backcalculation for determining deflection basin. Other structural analysis techniques, such as finite element method (FEM) and finite difference method (FDM), can be used to model flexible pavement structures when conducting FWD tests. Unlike FEM, MET analysis does not take into account nonlinear materials and dynamic loading. This study aims to develop a better finite element (FE) model by using the static and dynamic analyses in the ANSYS computer program. A comparative study was conducted by using varying sizes of model geometry and different types of elements and sizes to determine how they affect the developed FE model. The results of the analyses show that transient dynamic analysis is the best method for simulating FWD test. The percentage of errors between FE deflection basin and measured deflection basin range between 0.94 and 5.01%. Model geometry of 5000 × 5000 mm is sufficient to produce a good deflection basin which approximates the measured deflection. To ensure the accuracy of the developed model, the information on material properties must be valid. Additionally, finer and higher order elements should be used close to the loading region, for instance four or eight-node quadrilateral element (CAX4 or CAX8) with quadratic interpolation function
Radiopathological characteristics and outcomes of phyllodes tumor of the breast in Malaysian women
No full textPhyllodes tumor or cystosarcoma phyllodes is a rare fibroepithelial neoplasm which arises from the periductal stroma of the breast. They are classified as benign, borderline, and malignant based on the histologic features. However, all phyllodes tumor (PT) subtypes are regarded as having malignant potential and correct diagnosis is important for surgical management and optimal care. This study is a retrospective review of 76 women diagnosed as PT with highlights on the imaging characteristics, pathology, and surgical treatment over a 7-year period in a tertiary medical center of urban population in Malaysia. There were 45 benign, 16 borderline, and 15 malignant PT. The median age for benign PT was 43, borderline 48.5, and malignant 42 years. The Malay ethnic group constitute 52.6% of cases, with 27.6% and 18.4% in Chinese and Indian ethnic groups, respectively. On mammograms, most benign (64.3%) and 33.3% of malignant PT showed high-density lesions. Calcifications were only seen in 2 benign PT. On ultrasound, 86% of benign PT was well-circumscribed whilst 50.0% of malignant PT had irregular outline. Cystic spaces were seen in 40.0% of malignant and 9.5% of benign PT. 80% of malignant PT lesions were heterogenous. Malignant PT demonstrates tumor heterogeneity, cystic spaces, and posterior acoustic enhancement on ultrasound. Half of malignant PT showed regular borders on ultrasound and appear well circumscribed on mammogram. A total of 46 patients had wide local excision or excision biopsy whilst 30 underwent mastectomy as primary treatment. The majority of the borderline and malignant PTs in our study (75.0% and 85.7% respectively) and only 5 out of the 43 (11.6%) benign PT underwent mastectomy. There were 2 tumor recurrence in the benign PT group and 1 case in the borderline and malignant group respectively
Linking Soil Microbial Properties with Plant Performance in Acidic Tropical Soil Amended with Biochar
No full textSoil microbial properties are frequently used as indicators of soil fertility. However, the linkage of these properties with crop biomass is poorly documented especially in biochar amended soil with high carbon:nitrogen (C:N). A short-term field trial was conducted to observe the growth response of maize to biochar treatment in a highly weathered Ultisol of humid tropics and to observe the possible linkage of the measured microbial properties with maize biomass. Soil microbial biomass (carbon (C), nitrogen (N), phosphorus (P)), enzyme activity (β-glucosidase, urease, phosphodiesterase) and gene abundance (bacterial 16S rRNA, fungal ITS) were analyzed. For comparison, total soil C, N, and P were also analyzed. The data revealed no significant linkage of soil C, N, and P with maize biomass. A significant association of enzyme activity and gene abundance with maize biomass was not recorded. Strong positive correlation between maize above ground biomass with microbial biomass N was found (r = 0.9186, p < 0.01). Significant negative correlation was recorded between microbial biomass C:N with maize biomass (r = -0.8297, p < 0.05). These statistically significant linkages observed between microbial biomass and maize biomass suggests that microbial biomass can reflect the soil nutrient status, and possibly plant nutrient uptake. Estimation of microbial biomass can be used as a fertility indicator in soil amended with high C:N organic matter in the humid tropics
Flipped classroom approach for preschool students in learning English language
No full textAlong with technology advancements, the Malaysian education system needs to be transformed from a traditional system to an environment that is technology-based. In the Malaysian context, English is considered a second language to be acquired, thus barely practiced by students outside classroom or in daily life. Using Gagne’s theory, this study aims to identify the teaching and learning (T&L) processes carried out when using a flipped classroom (FC) approach. Findings show that students have positive responses toward the T&L processes using a FC approach. Three themes emerged during the interview process – children’s learning, video lectures and learning guidance. Thus, the contributions of the paper are to encourage the future English kindergarten teachers to implement FC in their T&L practices
Study of late-Mesozoic magmatic rocks and their related copper-gold-polymetallic deposits in the Guichi ore-cluster district, Lower Yangtze River Metallogenic Belt, East China
No full textThe Guichi ore-cluster district in the Lower Yangtze River Metallogenic Belt hosts extensive Cu–Au–Mo polymetallic deposits including the Tongshan Cu–Mo, Paodaoling Au, Matou Cu–Mo, Anzishan Cu–Mo, Guilinzheng Mo and Zhaceqiao Au deposits, mostly associated with the late Mesozoic magmatic rocks, which has been drawn to attention of study and exploration. However, the metallogenic relationship between magmatic rocks and the Cu–Au-polymetallic deposits is not well constrained. In this study, we report new zircon U–Pb ages, Hf isotopic, and geochemical data for the ore-bearing intrusions of Guichi region. LA-ICP-MS U–Pb ages for the Anzishan quartz diorite porphyrite is 143.9 ± 1.0 Ma. Integrated with previous geochronological data, these late Mesozoic magmatic rocks can be subdivided into two stages of magmatic activities. The first stage (150–132 Ma) is characterized by high-K calc-alkaline intrusions closely associated with Cu–Au polymetallic ore deposits. Whereas, the second stage (130–125 Ma) produced granites and syenites and is mainly characterized by shoshonite series that are related to Mo–Cu mineralization. The first stage of magmatic rocks is considered to be formed by partial melting of subducted Palaeo-Pacific Plate, assimilated with Yangtze lower crust and remelting Meso-Neoproterozoic crust/sediments. The second stage of magmatism is originated from partial melting of Mesoproterozoic-Neoproterozoic crust, mixed with juvenile crustal materials. The depression cross to the uplift zone of the Jiangnan Ancient Continent forms a gradual transition relation, and the hydrothermal mineralization composite with two stages have certain characteristics along the regional fault (Gaotan Fault). Guichi region results from two episodes of magmatism probably related to tectonic transition from subduction of Palaeo-Pacific Plate to back-arc extensional setting between 150 and 125 Ma, which lead to the Mesozoic large-scale polymetallic mineralization events in southeast China
Data mining based damage identification using imperialist competitive algorithm and artificial neural network
No full textCurrently, visual inspections for damage identification of structures are broadly used. However, they have two main drawbacks; time limitation and qualified manpower accessibility. Therefore, more precise and quicker technique is required to monitor the condition of structures. To aid the aim, a data mining based damage identification approach can be utilized to solve these drawbacks. In this study, to predict the damage severity of sin-gle-point damage scenarios of I-beam structures a data mining based damage identification framework and a hybrid algorithm combining Artificial Neural Network (ANN) and Imperial Competitive Algorithm (ICA), called ICA-ANN method, is proposed. ICA is employed to determine the initial weights of ANN. The efficiency coefficient and mean square error (MSE) are used to evaluate the performance of the ICA-ANN model. Moreover, the proposed model is compared with a pre-developed ANN approach in order to verify the efficiency of the proposed methodology. Based on the obtained results, it is concluded that the ICA-ANN indicates a better performance in detection of damage severity over the ANN method used only
Reduced expression of AURKA in peripheral blood of breast cancer patients
No full textAURKA, CENPW, and TIMP1 are reported to be genes involved in the regulation of the cell cycle and are highly associated with various cancers, including breast cancer (BC). These genes appear to be overexpressed in cancerous tissues, but unknown in peripheral blood. This study uses quantitative real-time PCR (qPCR) to assess the differential expression of AURKA, CENPW, and TIMP1 genes in the peripheral blood of BC patients and correlates expression levels with clinicopathological characteristics and etiological factors. We found that AURKA expression was significantly reduced in BC patients, as well as: 1) those without any family cancer history, 2) nonsmokers, and 3) those who engage in frequent consumption of red meat in the peripheral blood. However, all three genes in this study were not significantly correlated with clinicopathological characteristics of BC. Our study reveals that the expression of AURKA is significantly downregulated in the peripheral blood of BC patients
Measurement of coronary bifurcation angle with coronary CT angiography: A phantom study
No full textPurpose: Accurate determination of the bifurcation angle and correlation with plaque buildup may lead to the prediction of coronary artery disease (CAD). This work evaluates two techniques to measure bifurcation angles in 3D space using coronary computed tomography angiography (CCTA). Materials and Methods: Nine phantoms were fabricated with different bifurcation angles ranging from 55.3° to 134.5°. General X-ray and CCTA were employed to acquire 2D and 3D images of the bifurcation phantoms, respectively. Multiplanar reformation (MPR) and volume rendering technique (VRT) were used to measure the bifurcation angle between the left anterior descending (LAD) and left circumflex arteries (LCx). The measured angles were compared with the true values to determine the accuracy of each measurement technique. Inter-observer variability was evaluated. The two techniques were further applied on 50 clinical CCTA cases to verify its clinical value. Results: In the phantom setting, the mean absolute differences calculated between the true and measured angles by MPR and VRT were 2.4° ± 2.2° and 3.8° ± 2.9° respectively. Strong correlation was found between the true and measured bifurcation angles. Furthermore, no significant differences were found between the bifurcation angles measured using either technique. In clinical settings, large difference of 12.0° ± 10.6° was found between the two techniques. Conclusion: In the phantom setting, both techniques demonstrated a significant correlation to the true bifurcation angle. Despite the lack of agreement of the two techniques in the clinical context, our findings in phantoms suggest that MPR should be preferred to VRT for the measurement of coronary bifurcation angle by CCTA
Awareness, potential factors, and post-amputation care of stump flexion contractures among transtibial amputees
No full textObjectives: This study aims to assess the level of awareness of transtibial amputee patients on stump contractures and their compliance with efforts implemented to prevent the condition. Patients and methods: This study included 50 unilateral transtibial amputees (26 males, 24 females; mean age 55.4±14.7 years; range, 18 to 78 years) who met the respondent criteria of the study. The respondents were randomly selected and were issued with a questionnaire. Results: The majority of the transtibial amputees were aware of stump contracture complications. It was found that they also preferred methods of prevention which required less effort, was cost-effective, and were also practical. Conclusion: More focus should be placed on contracture prevention methods which were most complied with by the patients. This is because the effectiveness of a prevention method is highly influenced by patients’ compliance with the method. Patients with a higher risk of developing stump contractures should be also given more attention in post-amputation care
Green Product Preferences with Respect to Cultural Influences: Empirical Study in Indonesia
No full textNowadays, increasing awareness is directed toward the fulfilment of sustainability demands in production in rapidly developing Southeast Asian countries such as Indonesia. However, producing green products that satisfy customer preferences is still a challenging task for product designers and manufacturers. Cultural values can be a significant factor that influences customer preferences. The aim of this study is to investigate the influence of cultural values on green-product preferences. Data were statistically analyzed based on the fulfilment of critical threshold values for the modeling of a structural equation. According to the results, customer preferences in Indonesia were mostly influenced by uncertainty avoidance and long-term orientation. Further, additional product services were identified as the most important characteristic of green products for Indonesian customers