1,721,385 research outputs found
Alkaloids from Alstonia Macrophylla / Lim Siew Huah
Full text linkThe 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
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
Tanjong Karang survey - phase V a critical study of Sekinchan Long Heng Co-opereative rice mill society limited / Lim Siew Hoe.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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