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Lycopodium Alkaloids: Lycoplatyrine A, an Unusual Lycodine–Piperidine Adduct from Lycopodium platyrhizoma and the Absolute Configurations of Lycoplanine D and Lycogladine H
No full textThree new Lycopodium alkaloids comprising two lycodine-Type alkaloids (1, 2) and one fawcettimine alkaloid (3), in addition to 16 known alkaloids, were isolated from Lycopodium platyrhizoma. The structures of these alkaloids were elucidated based on analysis of their NMR and MS data. Lycoplatyrine A (1) represents an unusual lycodine-piperidine adduct. The structures and absolute configurations of lycoplanine D (hydroxy-des-N-methyl-α-obscurine, 10) and lycogladine H (11) were confirmed by X-ray diffraction analysis. © 2019 American Chemical Society and American Society of Pharmacognosy
A hybrid bat–swarm algorithm for optimizing dam and reservoir operation
No full textOne of the major challenges and difficulties to generate optimal operation rule for dam and reservoir operation are how efficient the optimization algorithm to search for the global optimal solution and the time-consume for convergence. Recently, evolutionary algorithms (EA) are used to develop optimal operation rules for dam and reservoir water systems. However, within the EA, there is a need to assume internal parameters at the initial stage of the model development, such assumption might increase the ambiguity of the model outputs. This study proposes a new hybrid optimization algorithm based on a bat algorithm (BA) and particle swarm optimization algorithm (PSOA) called the hybrid bat–swarm algorithm (HB-SA). The main idea behind this hybridization is to improve the BA by using the PSOA in parallel to replace the suboptimal solution generated by the BA. The solutions effectively speed up the convergence procedure and avoid the trapping in local optima caused by using the BA. The proposed HB-SA is validated by minimizing irrigation deficits using a multireservoir system consisting of the Golestan and Voshmgir dams in Iran. In addition, different optimization algorithms from previous studies are investigated to compare the performance of the proposed algorithm with existing algorithms for the same case study. The results showed that the proposed HB-SA algorithm can achieve minimum irrigation deficits during the examined period and outperforms the other optimization algorithms. In addition, the computational time for the convergence procedure is reduced using the HB-SA. The proposed HB-SA is successfully examined and can be generalized for several dams and reservoir systems around the world. © 2019, Springer-Verlag London Ltd., part of Springer Nature
Intramolecular Dimerization Quenching of Delayed Emission in Asymmetric D–D′–A TADF Emitters
No full textUnderstanding the excited-state dynamics and conformational relaxation in thermally activated delayed fluorescence (TADF) molecules, including conformations that potentially support intramolecular through-space charge transfer, can open new avenues for TADF molecular design as well as elucidate complex photophysical pathways in structurally complex molecules. Emissive molecules comprising a donor (triphenylamine, TPA) and an acceptor (triphenyltriazine, TRZ) bridged by a second donor (9,9-dimethyl-9-10-dihydroacridin, DMAC, or phenoxazine, PXZ) are synthesized and characterized. In solution, the flexibility of the sp3-hybridized carbon atom in DMAC of DMAC-TPA-TRZ, compared to the rigid PXZ, allows significant conformational reorganization, giving rise to multiple charge-transfer excited states. As a result of such a reorganization, the TRZ and TPA moieties become cofacially aligned, driven by a strong dipole-dipole attraction between the TPA and TRZ units, forming a weakly charge-transfer dimer state, in stark contrast to the case of PXZ-TPA-TRZ where the rigid PXZ bridge only supports a single PXZ-TRZ charge transfer (CT) state. The low-energy TPA-TRZ dimer is found to have a high-energy dimer local triplet state, which quenches delayed emission because the resultant singlet CT local triplet energy gap is too large to mediate efficient reverse intersystem crossing. However, organic light-emitting diodes using PXZ-TPA-TRZ as an emitting dopant resulted in external quantum efficiency as high as 22%, more than two times higher than that of DMAC-TPA-TRZ-based device, showing the impact that such intramolecular reorganization and donor-acceptor dimerization have on TADF performance. © 2019 American Chemical Society
Curcumin Nanoformulations for Colorectal Cancer: A Review
No full textColorectal cancer (CRC) is the third most prevalent form of cancer, after lung cancer and breast cancer, with the second highest death incidence. Over the years, natural compounds have been explored as an alternative to conventional cancer therapies such as surgery, radiotherapy, and chemotherapy. Curcumin, an active constituent of turmeric has been associated with various health benefits. It has gained much attention as an anticancer agent due to its ability to regulate multiple cell signaling pathways, including NF-κB, STAT3, activated protein-1 (AP-1), epidermal growth response-1 (Egr-1), and p53, which are crucial in cancer development and progression. Nevertheless, the clinical application of curcumin is greatly restricted because of its low water solubility, poor oral absorption, and rapid metabolism. These issues have led to the development of curcumin nanoformulations to overcome the limitations of the compound. Nanotechnology-based delivery systems have been widely used in improving the delivery of poorly-water soluble drugs. Besides, these systems also come with the added benefits of possible cellular targeting and improvement in cellular uptake. An ideal improved formulation should display a greater anticancer activity compared to free curcumin, and at the same time be non-toxic to the normal cells. In this review, we focus on the design and development of various nanoformulations to deliver curcumin for use in CRC such as liposomes, micelles, polymer nanoparticles, nanogels, cyclodextrin complexes, solid lipid nanoparticles (SLN), phytosomes, and gold nanoparticles. We also discuss the current pre-clinical and clinical evidences of curcumin nanoformulations in CRC therapy, analyse the research gap, and address the future direction of this research area. © 2019 Wong, Ngai, Chan, Lee, Goh and Chuah
Validation of a simple extraction procedure for bisphenol A identification from human plasma
No full textThe general population is exposed to bisphenol A (BPA) orally, parenterally, transdermally, and environmentally as a result of the use of BPA in food packaging, plastics, and personal care products. The majority of the population nowadays (91–99%) has detectable levels of BPA inside their body. In this study, we successfully performed an inexpensive, rapid, and simple protein precipitation procedure for extraction of BPA from human plasma, followed by analysis by LC-MS/MS. This method was specifically developed for handling large numbers of samples with minimum cost and volume of sample. The developed method was accurate, precise, and reproducible for quantification of BPA from human plasma samples in the concentration range of 10–2000 ng/mL. The method was performed on samples from 150 healthy volunteers who were enrolled in the study. The mean of observed BPA level was 2.22 ± 9.91 ng/mL. Higher BPA levels were observed for females compare to that of males (p-value = 0.002), the BPA levels were higher in participants 33 years of age and older compared to those less than 33 years of age (p-value = 0.000), then the BPA levels higher in subjects with tap water as source of drinking (p-value = 0.005). This method may be valuable for general risk assessment of BPA for a large and varied population because of its efficiency and economical aspects. © 2019 Wiraagni et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Factors Associated with Health Care Professionals’ Attitude Toward the Presumed Consent System
No full textObjectives: This paper explores health care pro - fessionals’ potential attitude toward organ donation if the presumed consent system were to be im - plemented in Malaysia, as well as factors associated with this attitude. Materials and Methods: We used self-administered questionnaires to investigate the attitude of 382 health care professionals from the University of Malaya Medical Center between January and February 2014. The responses were analyzed using logistic regression. Results: Of the 382 respondents, 175 (45.8%) stated that they would officially object to organ donation if the presumed consent system were to be imple - mented, whereas the remaining 207 (54.2%) stated that they would not object. The logistic regression showed that health care professionals from the Malay ethnic group were more likely to object than those from Chinese (adjusted odds ratio of 0.342; P =.001) and Indian and other (adjusted odds ratio of 0.341; P =.003) ethnic groups. Health care professionals earning 3000 Malaysian Ringgit or below were more likely to object than those earning above 3000 Malaysian Ringgit (adjusted odds ratio of 1.919; P =.006). Moreover, respondents who were initially unwilling to donate organs, regardless of the donation system, were more likely to object under the presumed consent system than those who were initially willing to donate (adjusted odds ratio of 2.765; P <.001). Conclusions: Health care professionals in Malaysia have a relatively negative attitude toward the presumed consent system, which does not encourage the implementation of this system in the country at present. To pave the way for a successful implementation of the presumed consent system, efforts should be initiated to enhance the attitude of health care professionals toward this system. In particular, these efforts should at most target the health care professionals who are Malay, earn a low income, and have a negative default attitude toward deceased donation. © Başkent University 2019
Prevalence and determinants of pathological internet use among undergraduate students in a public university in Malaysia
No full textPathological Internet Use (PIU) affects one's physical and mental health, and university students are at risk as they are more likely to develop PIU. This study determines the prevalence of PIU and its associated factors among students in a public university in Malaysia. This cross-sectional study was conducted among 1023 undergraduate students in 2015. The questionnaire comprised of items from the Young's Diagnostic Questionnaire to assess PIU and items related to socio-demography, psychosocial, lifestyle and co-morbidities. Anonymous paper-based data collection method was adopted. Mean age of the respondents was 20.73 ± 1.49 years old. The prevalence of pathological Internet user was 28.9% mostly Chinese (31%), 22 years old and above (31.0%), in Year 1 (31.5%), and those who perceived themselves to be from family from higher socio-economic status (32.5%). The factors found statistically significant (p < 0.05) with PIU were Internet use for three or more hours for recreational purpose (OR: 3.89; 95% CI:1.33 - 11.36), past week of Internet use for pornography purpose (OR: 2.52; 95% CI:1.07 - 5.93), having gambling problem (OR: 3.65; 95% CI:1.64 - 8.12), involvement in drug use in the past 12 months (OR: 6.81; 95% CI:1.42 - 32.77) and having moderate/severe depression (OR: 4.32; 95% CI:1.83 - 10.22). University authorities need to be aware of the prevalence so that interventions can be developed to prevent adverse outcomes. Interventions should focus on screening students for PIU, creating awareness on the negative effects of PIU and promoting healthy and active lifestyle and restricting students' access to harmful websites. © Behavioral Science Research Institute
Interactive 3D visualization for tropical plant species
Get PDFAugmented Reality (AR) is gaining more popularity nowadays as AR enables the user to see, hear and feel the virtual elements in the real world. The advancement in AR has made an impressive remark in the field of game, education, tourism, exploration, and advertising. In this research, an interactive 3D visualization for tropical plant species is developed. It provides the user with better visualization of plant species through AR. It permits the user to view three-dimensional rotatable models through a marker in a book, on a pamphlet or on signage. It enables the user to have a better idea of how the plants would look like in real life rather than plain two-dimensional images. In order to track the 3D models, markers or image targets are developed to track various 3D plant models. The AR markers developed are rich in detail, good contrast and with no repetitive patterns to have the good tacking ability. This research consists of five main stages which are image acquisition, 3D model construction, marker design, integration of 3D model into marker, and graphical user interface (GUI) design. This application permits the user to access the 3D models of the topical plant species with the availability of the marker anywhere and anytime. In addition, it is portable and low-cost interactive learning material for school children as well as the public
A newly developed porcine training model for transurethral piecemeal and en bloc resection of bladder tumour
No full textPurpose: The Asian Urological Surgery Training & Education Group (AUSTEG) has been established to provide training and education to young urologists in Asia. We developed and validated a porcine bladder training model for transurethral resection of bladder tumour (TURBT). Methods: Urology residents and specialists were invited to test the training model. They were asked to complete a pre-task questionnaire, to perform piecemeal and en bloc resection of ‘bladder tumours’ within the training model, and to complete a post-task questionnaire afterwards. Their performances were assessed by faculty members of the AUSTEG. For the face validity, a pre-task questionnaire consisting of six statements on TURBT and the training model were set. For the content validity, a post-task questionnaire consisting of 14 items on the details of the training model were set. For the construct validity, a Global Rating Scale was used to assess the participants’ performances. The participants were stratified into two groups (junior surgeons and senior surgeons groups) according to their duration of urology training. Results: For the pre-task questionnaire, a mean score of ≥ 4.0 out of 5.0 was achieved in 5 out of 6 statements. For the post-task questionnaire, a mean score of ≥ 4.5 out of 5.0 was achieved in every item. For the Global Rating Scale, the senior surgeons group had higher scores than the junior surgeons group in 8 out of 11 items as well as the total score. Conclusion: A porcine TURBT training model has been developed, and its face, content and construct validity has been established. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
Parameter estimation by minimizing a probability generating function-based power divergence
No full textGenerating function-based statistical inference is an attractive approach if the probability (density) function is complicated when compared with the generating function. Here, we propose a parameter estimation method that minimizes a probability generating function (pgf)-based power divergence with a tuning parameter to mitigate the impact of data contamination. The proposed estimator is linked to the M-estimators and hence possesses the properties of consistency and asymptotic normality. In terms of parameter biases and mean squared errors from simulations, the proposed estimation method performs better for smaller value of the tuning parameter as data contamination percentage increases. © 2018, © 2018 Taylor & Francis Group, LLC