60 research outputs found

    New quinazolinone-based Mannich bases: Synthesis and in vitro cytotoxic evaluation

    Get PDF
    This research presents the synthesis of new quinazolinone-based Mannich bases in good yields via a three-step procedure. The first step is the reaction of 6-hydroxyanthranilic acid 1 with an excess of acetic anhydride at 150°C for 2 h to afford benzoxazinone 2 in 87% yield. Compound 2 is then reacted with 4-aminophenol in DMSO at reflux for 7 h to give compound 3 in 75% yield. Finally, the reaction of 3 with paraformadehyde and secondary amines in ethanol affords new quinazolinone-based Mannich bases 4a-c and 5a-e in 55-70% yields. The structure of Mannich bases have been characterized by NMR and MS spectra. The bio-assay results show that some new Mannich bases exhibited weak to moderate cytotoxic activity against SKLu-1 and MCF-7 cell lines

    A Study Of UV-curable Offset Ink Emulsified With An Alternative Isopropyl Alcohol-free Fountain Solution

    Get PDF
    In the present research, fountain solution without isopropyl alcohol (IPA) for Ultraviolet offset curing ink (UV ink) was prepared by using Ethylene Glycol Mono-butyl Ether (EGME) as a substitute for IPA. The effect of EGME concentration on the water pick-up characteristics, tack value, rheological behaviors, and curing time of UV offset inks was investigated. Water pick-up characteristics, tack value and rheological behaviors were measured by Duke Ink water emulsification tester, Tack-o-scope and cone-plate rheometer, respectively. The curing time of the UV ink was evaluated by the rub test of printed sheet samples proofed on the polymer film at the standard solid ink density and the same ink thickness. The results revealed that an increase in EGME concentration increased the water pick-up characteristics of the UV ink. There was no significant influence of EGME on the tack value of UV inks. However, the tack value of UV ink was significantly affected by fountain concentration in UV inks and UV ink color. The addition of EGME reduced the dynamic viscosity and thixotropic property of UV inks but did not change the flow behavior of UV ink as shear thinning. This study indicates that UV ink emulsified with a higher EGME concentration fountain solution needs a longer curing time. The cyan UV ink has the longest curing time. Finally, the fountain solution of 10% EGME exhibited good performance in water pick-up characteristics, tack value, rheological behaviors, and curing time of UV inks

    Computation-effective structural performance assessment using Gaussian Process-based finite element model updating and reliability analysis

    Get PDF
    Structural health monitoring data has been widely acknowledged as a significant source for evaluating the performance and health conditions of structures. However, a holistic framework that efficiently incorporates monitored data into structural identification and, in turn, provides a realistic life-cycle performance assessment of structures is yet to be established. There are different sources of uncertainty, such as structural parameters, computer model bias and measurement errors. Neglecting to account for these factors results in unreliable structural identifications, consequent financial losses, and a threat to the safety of structures and human lives. This paper proposes a new framework for structural performance assessment that integrates a comprehensive probabilistic finite element model updating approach, which deals with various structural identification uncertainties and structural reliability analysis. In this framework, Gaussian process surrogate models are replaced with a finite element model and its associate discrepancy function to provide a computationally efficient and all-round uncertainty quantification. Herein, the structural parameters that are most sensitive to measured structural dynamic characteristics are investigated and used to update the numerical model. Sequentially, the updated model is applied to compute the structural capacity with respect to loading demand to evaluate its as-is performance. The proposed framework's feasibility is investigated and validated on a large lab-scale box girder bridge in two different health states, undamaged and damaged, with the latter state representing changes in structural parameters resulted from overloading actions. The results from the box girder bridge indicate a reduced structural performance evidenced by a significant drop in the structural reliability index and an increased probability of failure in the damaged state. The results also demonstrate that the proposed methodology contributes to more reliable judgment about structural safety, which in turn enables more informed maintenance decisions to be made

    Lung Volume Reduction Surgery in Patients with Heterogenous Emphysema: Selecting Perspective

    Get PDF
    BACKGROUND: Lung volume reduction surgery (LVRS) was introduced to alleviate clinical conditions in selected patients with heterogenous emphysema. Clarifying the most suitable patients for LVRS remained unclear. AIM: This study was undertaken to specifically analyze the preoperative factor affecting to LVRS. METHODS: The prospective study was conducted at 103 Military Hospital between July 2014 and April 2016. Severe heterogenous emphysema patients were selected to participate in the study. The information, spirometry, and body plethysmographic pulmonary function tests in 31 patients who underwent LVRS were compared with postoperative outcomes (changing in FEV1 and CAT scale). RESULTS: Of the 31 patients, there was statistically significant difference in the outcome of functional capacity, lung function between two groups (FEV1 ≤ 50% and > 50%) (∆FEV1: 22.46 vs 18.32%; p = 0.042. ∆CAT: 6.85 vs 5.07; p = 0.048). Changes of the FEV1 and CAT scale were no statistically significant differences in three groups residual volume. Patients with total lung capacity < 140% had more improved than others (∆FEV1: 23.81 vs 15.1%; p = 0.031). CONCLUSION: Preoperative spirometry and body plethysmographic pulmonary function tests were useful measures to selected severe heterogenous emphysema patients for LVRS. Patients with FEV1 ≤ 50%, TLC in the range of 100-140% should be selected

    Light Absorption and Luminescence Properties of the Blend Poly(N-vinylcarbazole)/Poly(N-hexylthiophene)

    Get PDF
    We have investigated the enhancement absorption light and luminescence properties of the blend conducting polymers using poly(N-vinylcarbazole) and poly(N-hexylthiophene). The optimized material showed a broad absorption in the region of ultra violet to near infra-red and the better of luminescence ability than the pristine conducting polymers. The remarkable improvements in photoluminescences of the blends provide useful information to the application of this material in fabrication of optical – electronic devices.

    Awareness and preparedness of healthcare workers against the first wave of the COVID-19 pandemic: A cross-sectional survey across 57 countries.

    Get PDF
    BACKGROUND: Since the COVID-19 pandemic began, there have been concerns related to the preparedness of healthcare workers (HCWs). This study aimed to describe the level of awareness and preparedness of hospital HCWs at the time of the first wave. METHODS: This multinational, multicenter, cross-sectional survey was conducted among hospital HCWs from February to May 2020. We used a hierarchical logistic regression multivariate analysis to adjust the influence of variables based on awareness and preparedness. We then used association rule mining to identify relationships between HCW confidence in handling suspected COVID-19 patients and prior COVID-19 case-management training. RESULTS: We surveyed 24,653 HCWs from 371 hospitals across 57 countries and received 17,302 responses from 70.2% HCWs overall. The median COVID-19 preparedness score was 11.0 (interquartile range [IQR] = 6.0-14.0) and the median awareness score was 29.6 (IQR = 26.6-32.6). HCWs at COVID-19 designated facilities with previous outbreak experience, or HCWs who were trained for dealing with the SARS-CoV-2 outbreak, had significantly higher levels of preparedness and awareness (p<0.001). Association rule mining suggests that nurses and doctors who had a 'great-extent-of-confidence' in handling suspected COVID-19 patients had participated in COVID-19 training courses. Male participants (mean difference = 0.34; 95% CI = 0.22, 0.46; p<0.001) and nurses (mean difference = 0.67; 95% CI = 0.53, 0.81; p<0.001) had higher preparedness scores compared to women participants and doctors. INTERPRETATION: There was an unsurprising high level of awareness and preparedness among HCWs who participated in COVID-19 training courses. However, disparity existed along the lines of gender and type of HCW. It is unknown whether the difference in COVID-19 preparedness that we detected early in the pandemic may have translated into disproportionate SARS-CoV-2 burden of disease by gender or HCW type

    Structural damage identification using experimental modal parameters via correlation approach

    No full text
    This research provides a new damage identification strategy using experimental modal parameters via correlation approach. Two damage identification algorithms using modal strain energy-eigenvalue ratio (MSEE) are presented. Firstly, a method using a simplified term of MSEE called geometric modal strain energy-eigenvalue ratio (GMSEE) is developed. Secondly, the original method is modified using the full term of MSEE, proving better capability of damage identification when used with fewer vibration modes. Performance of the proposed damage identification algorithms has been successfully validated with a numerical model and some experimental models of various scales from small to large

    Study of organizational structure & empowerment profile of construction companies in Singapore

    No full text
    Since 1965, Singapore has undergone vast transformation from a Third-world young nation to a First-world country. In the modern world where change is the only constant, Construction Industry must be able to adapt and even take advantage of change for highest benefit. In fact, when capital is no longer a deciding factor of success; superior project management is and will be the cutting edge, separating individual firms from the herds. Two major aspects in Project Management include Organization structure which defines various hierarchical natures of power and deciding how the enterprise should be run, and Empowerment determining how much autonomy and authority of an individual. In construction industry, most project managers must take full responsibility for project implementation and outcomes. However, they might not have full authority to execute the jobs which in turn reduces the project efficiency and effectiveness, suggesting a possible causal-effect relationship of Organization Structures, Empowerment profiles with success of construction projects. Motivated by the relationship of Organization Structure and Empowerment, this dual-Final Year Project aims to investigate organizational behaviors of contractors of various financial grades (A1 to B2) through survey questionnaires and statistical analysis. With collaborated effort between two student-researchers, the report shares common features in Background Studies and Research Method. To make the research more meaningful, study results are presented independently by each student in light of Organizational Structures or Empowerment Profile. In addition, possible statistical correlations between related management dimensions are discussed and further enriched by a Case study done with four construction firms, which aimed to give the most genuine insights on Project Management in the 21st century. This report focuses on the Empowerment Profile part of the study.Bachelor of Engineering (Civil
    • …
    corecore