5,209 research outputs found
Alkaloids from Alstonia Macrophylla / Lim Siew Huah
No full textThe Malaysian plant, Alstonia macrophylla Wall, was investigated for its alkaloidal content and the results are summarized in the Table below. A total of 90 alkaloids were isolated and characterized from the leaf and stem-bark of A. macrophylla. Of these, 30 are new alkaloids. The leaf extract of A. macrophylla yielded a total of 13 new alkaloids, including a macroline indole 1, a macroline oxindole 16, eight akuammiline alkaloids (compounds 24, 25, 26, 27, 28, 29, 30, and 31), a sarpagine alkaloid 32, and two ajmaline alkaloids (compounds 33 and 34). The stem-bark extract of A. macrophylla gave a total of 19 new alkaloids. These include, in addition to the akuammiline and sarpagine alkaloids found in the leaf extract (24 and 32, respectively), compound 2, 3, 4, 17, the linearly fused bisindole alkaloids, lumutinines A‒E (7175), the macroline-macroline bisindoles, lumusidines AD (7780) and perhentidines A‒B (81and 82), and the macrolinepleiocarpamine bisindole alkaloids, villalstonidines B (86) and F (87). Perhentidines A‒B (81 and 82), perhentinine (83), villalstonine (88) and macrocarpamine (90), showed pronounced cytotoxicity toward KB cells (IC50 2.644.06 g/mL), while lumutinines A‒E (71‒75), macralstonidine (76), lumusidines A-C (77‒79), anhydromacralstonine (85), and villalstonidine B (86) showed moderate cytotoxicity toward KB cells (IC50 4.3018.14 g/mL). Compounds 24, 25, 26, 29, 31, 32, lumusidine D (80), and macralstonine (84) showed strong activity in circumventing MDR in vincristine-resistant KB cells (IC50 0.055.03 g/mL)
KOMPETENSI ICT PEMIMPIN SEKOLAH
No full textLaporan Kajian SchoolNet dan Peranan ICT dalam Pendidikan yang dilaksanakan oleh
Boston Consulting Group (BCG) menyatakan bahawa tahap literasi ICT dalam kalangan
pemimpin sekolah adalah rendah. Laporan tersebut telah mencadangkan inisiatif “ensure
that Principals are minimally ICT literate and users of ICT”. Cadangan yang disarankan
ialah memberikan latihan bagi memastikan pemimpin sekolah mempunyai tahap literasi
ICT yang bersesuaian. Kajian ini dilaksanakan untuk meninjau tahap kompetensi ICT
dalam kalangan pemimpin sekolah. Dapatan kajian juga digunakan sebagai input untuk
mengkaji semula kurikulum latihan pada masa akan datang. Kajian tinjauan ini dijalankan
ke atas seramai 211 orang pemimpin sekolah di enam buah pejabat daerah pelajaran
yang terpilih dengan menggunakan instrumen yang dibangunkan. Instrumen Kompetensi
ICT Pemimpin Sekolah telah digubal untuk meninjau persepsi responden tentang tahap
kompetensi ICT mereka. Kompetensi ICT pemimpin sekolah ditinjau dalam enam
domain iaitu dasar dan kepimpinan, pembudayaan ICT dalam organisasi, pengetahuan
dan kemahiran ICT, pengurusan dan pentadbiran ICT, pembangunan keupayaan ICT
organisasi; serta isu sosial, perundangan dan etika ICT. Pada keseluruhannya, responden
berpendapat bahawa tahap kompetensi ICT mereka berada pada tahap tinggi bagi
keenam-enam domain dengan min antara 3.79 hingga 3.90. Namun jika dilihat secara
mendalam, terdapat tahap sederhana dalam dua indikator tertentu iaitu pengetahuan dan
kemahiran prisian produktiviti, serta kerjasama pintar. Dapatan tinjauan ini dicadangkan
menjadi satu asas untuk meneruskan kajian ke atas ke semua pemimpin sekolah bagi
mendapatkan gambaran yang sebenar kompetensi ICT dalam kalangan pemimpin sekolah
sj-pdf-1-trr-10.1177_03611981231206160 – Supplemental material for Role of U.S. Airports’ Attributes in the Output Response to the COVID-19 Pandemic: A Stochastic Frontier Analysis with the Difference-in-Differences Method
No full textSupplemental material, sj-pdf-1-trr-10.1177_03611981231206160 for Role of U.S. Airports’ Attributes in the Output Response to the COVID-19 Pandemic: A Stochastic Frontier Analysis with the Difference-in-Differences Method by Fecri Karanki and Siew Hoon Lim in Transportation Research Record</p
<b>Supplemental Material - Enhancing the hospital at home experience</b>
No full textSupplemental Material for Enhancing the hospital at home experience by Rachel Marie Towle, Peijin Esther Monica Fan, Juweita Arba’in, Fazila Aloweni, Siew Hoon Lim, Shin Yuh Ang and Su-Fee Lim in Proceedings of Singapore Healthcare.</p
Supplemental_material_for_DNA_Switch_Toehold_Mediated_DNA_Isothermal_Amplification_for_Dengue_Serotyping_by_Chan,_et_al – Supplemental material for DNA Switch: Toehold-Mediated DNA Isothermal Amplification for Dengue Serotyping
No full textSupplemental material, Supplemental_material_for_DNA_Switch_Toehold_Mediated_DNA_Isothermal_Amplification_for_Dengue_Serotyping_by_Chan,_et_al for DNA Switch: Toehold-Mediated DNA Isothermal Amplification for Dengue Serotyping by Soo Khim Chan, Akinori Kuzuya, Yee Siew Choong and Theam Soon Lim in SLAS Discovery</p
Fig. 5 in Polyneurines A H, iboga alkaloids from Tabernaemontana polyneura
No full textFig. 5. Proposed biosynthetic pathway to 1.Published as part of Tang, Sin-Yee, Tan, Chun-Hoe, Sim, Kae-Shin, Yong, Kien-Thai, Lim, Kuan-Hon, Low, Yun-Yee & Lim, Siew-Huah, 2023, Polyneurines A H, iboga alkaloids from Tabernaemontana polyneura, pp. 113587 in Phytochemistry (113587) 208 on page 8, DOI: 10.1016/j.phytochem.2023.113587, http://zenodo.org/record/816067
Polyneurines A H, iboga alkaloids from Tabernaemontana polyneura
No full textTang, Sin-Yee, Tan, Chun-Hoe, Sim, Kae-Shin, Yong, Kien-Thai, Lim, Kuan-Hon, Low, Yun-Yee, Lim, Siew-Huah (2023): Polyneurines A H, iboga alkaloids from Tabernaemontana polyneura. Phytochemistry (113587) 208: 113587, DOI: 10.1016/j.phytochem.2023.113587, URL: http://dx.doi.org/10.1016/j.phytochem.2023.11358
Fig. 1 in Polyneurines A H, iboga alkaloids from Tabernaemontana polyneura
No full textFig. 1. Structures of compounds 1–11, 14, and 20–21.Published as part of Tang, Sin-Yee, Tan, Chun-Hoe, Sim, Kae-Shin, Yong, Kien-Thai, Lim, Kuan-Hon, Low, Yun-Yee & Lim, Siew-Huah, 2023, Polyneurines A H, iboga alkaloids from Tabernaemontana polyneura, pp. 113587 in Phytochemistry (113587) 208 on page 2, DOI: 10.1016/j.phytochem.2023.113587, http://zenodo.org/record/816067
Analysis of Lim1 LIM domains in mouse development
No full textTranscriptional regulation is fundamental for the precise development of all organisms. Through tight regulation, necessary genes are activated at proper spatial and temporal patterns, while unnecessary genes are repressed. A large family of regulator proteins that have been demonstrated to be involved in various developmental processes by activation and repression of target genes is the homeodomain family of proteins. To date, the function of many of these homeoproteins has been elucidated in diverse species. However, the molecular mechanism underlying the function of these proteins has not been fully understood. In this study, the molecular mechanism of the function of a LIM-homeoprotein, Lim1, was examined. In addition to the homeodomain, Lim1 contains two LIM domains that are highly conserved among species. This high conservation along with data from in vitro studies on Xenopus Lim1 suggests that the LIM domains might be important for the function of Lim1 as a transcriptional regulator. Here, the functional importance of the LIM domains of Lim1 was determined by using a novel gene-targeting strategy in mouse embryonic stem (ES) cells. A cre-loxP system was used in conjunction with the unique genomic organization of Lim1 to obtain four types of mutant ES cell lines that would allow for the in vivo analysis of the function of both the LIM domains of Lim1 together and also singularly. These four mutant Lim1 alleles either contained base-pair changes at the LIM encoding exons that alters zinc-binding amino acids of the LIM domains or contained only exogenous loxP sequences in the first intron of Lim1, which serves as the control allele. These mutations in the LIM domains would presumably abolish the zinc-finger tertiary structure of the domain and thus render the domain non-functional. Mice carrying mutations at both the LIM domains of Lim1, L1L2, die around E10 without anterior head structures anterior to rhombomere 3, identical in phenotype to the Lim1 null mutants in spite of the presence of mutant Lim1 RNA. This result demonstrates that the integrity of both the LIM domains are essential for the function of Lim1. This is further supported by the phenotype of mice carrying mutation at only the second LIM domain of Lim1, L2. The L2 mice although still carrying one intact Lim1 LIM domain, also die in utero. The L2 mice die at varying times, from around E8 to E10 with anterior defects in addition to other axial defects which have yet to be fully characterized. The results of this study so far demonstrates that the integrity of both LIM domains are required for the function of Lim1
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