19672 research outputs found
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Ceramicines M–P from Chisocheton ceramicus: isolation and structure–activity relationship study
No full textCeramicines are a series of limonoids which were isolated from the bark of Malaysian Chisocheton ceramicus (Meliaceae) and show various biological activities. Ceramicine B, in particular, has been reported to show a strong lipid droplet accumulation (LDA) inhibitory activity on a mouse pre-adipocyte cell line (MC3T3-G2/PA6). With the purpose of discovering compounds with stronger activity than ceramicine B, we further investigated the constituents of C. ceramicus. As a result, from the bark of C. ceramicus four new ceramicines (ceramicines M–P, 1–4) were isolated, and their structures were determined on the basis of NMR and mass spectroscopic analyses in combination with NMR chemical shift calculations. LDA inhibitory activity of 1–4 was evaluated. Compounds 1–3 showed LDA inhibitory activity, and 3 showed better selectivity than ceramicine B while showing activity at the same order of magnitude as ceramicine B. Since 3, which possess a carbonyl group at C-7, showed better selectivity than 5, which possess a 7α-OH group, while showing activity at the same order of magnitude as 5, we also investigated the effect of the substituent at C-7 by synthesizing several derivatives and evaluating their LDA inhibitory activity. Accordingly, we confirmed the importance of the presence of a 7α-OH group to the LDA inhibitory activity
Chemical constituents of essential oils of Boesenbergia armeniaca and B. stenophylla (Zingiberaceae) endemic to Borneo
No full textBoesenbergia armeniaca and B. stenophylla are two endemic wild gingers from Borneo. Limited information are available on these wild species. The aim of this study was to identify the leaf essential oil constituents using hydrodistillation and analysed via GC-FID and GC-MS. The essential oil yields of leaves obtained from B. armeniaca and B. stenophylla were 0.01% and 0.08% respectively. The leaf oil of B. armeniaca was dominated by oxygenated sesquiterpenes (47.95%), while the leaf oil of B. stenophylla was dominated by oxygenated monoterpenes (85.12%). The main volatile constituents in the leaf oil of B. armeniaca were Nerolidol (42.55%), Linalool (11.63%) and β-caryophyllene (6.25%) while in the leaf oil of B. stenophylla, methyl cinnamate (83.17%) was most abundant. To date, this is the first report revealing the essential oil components of Boesenbergia armeniaca and B. stenophylla from Sabah, Borneo
Analysing the conceptual framework of religious freedom and interreligious relationship in Islam
No full textThis study evaluates the concept of religious freedom and interreligious relationships in Islam. The research engages in textual analysis and historical interpretation of the Qur'an and Sunnah (the Prophetic tradition) regarding the freedom of religious beliefs and practices as well as Muslim relationships with people of other religions. The study shows that Islam plays a unique role in providing every individual with the complete freedom to possess and practice any religion, culture or ideology. It also shows that as a universal religion, Islam advocates a harmonious relationship among the people of different religions, cultures and civilisations for the peaceful coexistence and harmonious development of all human beings. The study concludes that Islam as a complete way of life preserves the beliefs and practices of every individual and maintains a peaceful relationship between the followers of one religion and another. It constitutes a viable model for resolving religious hatred and promoting peace and justice among people of diverse ethnic, religious and cultural backgrounds
Does bank regulation matter on the relationship between competition and financial stability? Evidence from Southeast Asian countries
No full textThis study examines the role of bank regulation on the relationship between competition and financial stability. The considered regulations are capital requirements, activity restrictions, deposit insurance, and official supervision based on prior literature. We used data from the banking sector of Southeast Asian countries over the period of 1990–2014. Using system Generalized Method of Moments (GMM) and considering financial freedom and property right as instrumental variables, this study found that competition promotes financial stability, and reduces credit risk. Further, capital requirements and official supervision are the most effective and straightforward bank regulations promoting financial stability irrespective of the level of competition. Activity restrictions are effective in shaping financial stability only in a highly competitive environment, while deposit insurance promotes financial stability in a less competitive environment. This study provides a framework to determine the bank regulation best suited to promote financial stability through the channel of competition
Late Silurian cephalopods from Langkawi, Malaysia, with peri-Gondwanan faunal affinity
No full textNine species of late Pridoli (latest Silurian) orthocerid cephalopods are described from the Upper Setul Limestone of Pulau Langgun, Langkawi Islands, Malaysia. These are the orthoceratids Michelinoceras (Michelinoceras) cf. michelini (Barrande, 1866), Michelinoceras? sp., Kopaninoceras setulense sp. nov., Mimogeisonoceras? langgunense sp. nov., Kionoceras? sp. and Orthocycloceras sp.; the arionoceratids Arionoceras mahsuri sp. nov. and Caliceras mempelamense sp. nov.; and the geisonoceratid Murchisoniceras? sp. This is the first detailed record with taxonomic descriptions of Silurian cephalopods from Southeast Asia. The assemblage belongs to the newly defined Kopaninoceras Fauna that is interpreted to have been widely distributed along the northern (African to Asian) margin of Gondwana and around the Prototethys Ocean during the late Silurian. The Kopaninoceras Fauna includes a local assemblage from the Kurosegawa Belt of south-west Japan, which possibly represents its northernmost occurrence. The distribution of the Kopaninoceras Fauna implies that the cephalopod faunas of Kazakhstan and adjacent areas in Central Asia have closer affinities with peri-Gondwanan faunas than with Baltica or Siberia, corroborating conclusions drawn by earlier researchers based on the benthic faunas. http://zoobank.org/urn:lsid:zoobank.org:pub:DDE20872-C142-4B78-B5F2-2E604C3C8689
Enantiomeric pairs of copper(II) polypyridyl-alanine complex salts: anticancer studies
No full textThe anticancer properties of two previously characterized pairs of optically pure chiral complex salts [Cu(phen)(ala)(H2O)]X·xH2O (phen = 1.10-phenanthroline; X = NO3 −; ala: l-alanine (l-ala) 1 and d-alanine (d-ala) 2; and (X = Cl−; ala: l-ala, 3 and d-ala, 4; x = number of lattice water molecules) are reported herein, together with the crystal structure of the d-enantiomer 4. Unlike cisplatin which is ineffective against MCF-7 cancer cells with the absence of caspase-3 protein expression, these two pairs of complex salts were effective against this cell line and they were able to induce an increase in intracellular ROS, loss in mitochondrial membrane potential, cell cycle arrest mainly at SubG1 phase , caspase-9 activation, and caspase-3/caspase-7-independent apoptosis. Screening of 1 on the NCI-60 panel of human cancer cell lines showed that it was effective against most of the cell lines. MTT-NCI modified assay screening was also done on other cancer cell lines, viz. A549, CNE1, and HepG2, and two normal cell lines, viz. MCF-10A and CHANG. The effects of chirality of these Cu(II) compounds, especially the greater selectivity of d-enantiomers over the l-counterparts, on their anticancer properties are also reported herein
Calcium phosphate nanoparticles prepared via solid-state route
No full textTo date, the direction of bioceramic research is focused on the improvement of the mechanical performance and biological properties of existing bioactive ceramics particularly HA. Hence, the synthesis of crystalline HA nanoparticles with expected microstructure is of primary importance because the process directly relates to the phase purity, morphology, and particle size of the final HA particles. In this work, a simple and cost-effective technique, solid state reaction method was successfully employed to synthesize highly crystalline, high purity and single phase nanostructured hydroxyapatite powder using waste eggshells (HA-Es). The process involved mixing calcined eggshell powder and dicalcium hydrogen phosphate di-hydrate followed by a heat treatment at 800 °C for 5 hours. The resultant flower-like nanostructure HA powder is composed of leaf-like flakes having 100-200 nm width and crystallite size calculated using XRD data of ~56.21 nm
Effect of sintering temperature on the microstructures and mechanical properties of sodalite infiltrate all-ceramic material for dental restorations
No full textPotassium bromide sodalite (KBr-SOD) zeolite has been developed to enhance the mechanical properties of these restorations using a direct in situ hydrothermal condition followed by the sintering process. The purpose of this study was to determine the effects of sintering temperature on the microstructures and mechanical properties of porous alumina (A) and zirconia-toughened alumina (ZTA) discs infiltrated by KBr-SOD. Hundred and twenty disc-shaped samples were sintered at various temperatures and prepared for biaxial flexural strength and Vickers microhardness tests. The results showed that sintering temperatures from 1100 to 1600°C for both A-SOD and ZTA-SOD samples has resulted in a significant improvement in the density (2.8 and 1.1%, respectively), flexural strength (257 and 254%, respectively), Vickers hardness (109 and 112%, respectively), and Weibull modulus (7.5 and 3%, respectively). The present study concludes that infiltrated SOD material sintered at 1600°C is suitable for the fabrication of all-ceramic dental prostheses with adequate mechanical properties
Heterogeneity in studies of p16 in cervical lesions in different malaysian institutions: Time to consider collaborative study
No full textIntroduction: Clinical decision making becomes difficult when clinical and methodological heterogeneity does not permit synthesis of results of multiple small studies. Aim: For studies done in Malaysia, to identity the sample sizes and heterogeneity present in the various studies which used p16 in evaluating lesions of the cervix. To evaluate if it would be possible for a single study to answer the various questions posed by the original authors. To highlight areas where the design features of future studies can be optimised. Materials and Methods: Various databases were searched using synonyms for p16 AND cervix AND Malaysia. These were assessed for broad conformity to a Diagnostic Test Accuracy format. Methodological and clinical heterogeneity indicators were extracted into standardised fields. Results: There were 5 studies eligible for inclusion. Each sought to study different aspects of the disease such as diagnostic grade stratification and pathogenesis. The study type broadly conformed to a Diagnostic Test Accuracy format. The study design used was either consecutive or non-consecutive. Sample size ranged from 75 to 201. Clinical heterogeneity was present in the choice of controls with some using normal and some using inflamed tissue. Methodological heterogeneity in applying the reference test, index test and different antibody clones were present. Conclusion: There was both clinical and methodological heterogeneity making synthesis of studies difficult. It is possible to design a study which would be able to answer all the questions posed by the original authors with internal validity while at the same time increasing sample size
Biological properties and chemical diversity of Sinularia Flexibilis, an Alcyonacean Soft Coral
No full textSoft corals of the genus Sinularia (order Alcyonacea) are one of the most widespread sessile organisms in the Indo-Pacific waters. Unlike the hard corals, the major portion of soft coral is made up of inorganic skeletons consisting of calcareous spicules surrounded by a thin layer of tissue. This layer of tissue, made up of fleshy colonies with organic matter, is responsible in diversity of secondary metabolites. In order to survive the outburst of algal bloom, dynamic of microbial growth and predation of marine organisms, these soft corals synthesize unique chemicals as part of defense mechanism that makes them unpalatable to most marine life. As such, members of the genus Sinularia exhibits a diversity of secondary metabolites ranging from sesquiterpenes, diterpenes, polyhydroxylated steroids, and polyamine compounds. These metabolites had been shown to possess various biological activities such as antimicrobial, anti-inflammatory and cytotoxicity. This present paper reviews the chemistry and highlights the potential biological activities of metabolites from Sinularia flexibilis and provides a perspective for future research