1,720,964 research outputs found
Kimia analitik untuk mahasiswa farmasi
No full textDalam buku ini, diuraikan berbagai metode analisis, baik metode on-instrumental dan metode instrumental, seperti metode volumetri, spektroskopi dan kromatografi serta validasi metode analisis untuk memudahkan mahasiswa dalam memilih metode yang sesuai ketika melakukan analisis senyawa obat
ANALISIS VITAMIN B6 (PIRIDOKSIN) PADA SEDIAAN TABLET MULTIVITAMIN NEUROTROPI MENGGUNAKAN SPEKTROFOTOMETRI UV-VIS
Get PDFLatar Belakang : Analisis vitamin B6 dalam sediaan tablet multivitamin neurotropic membutuhkan metode yang simple, cepat serta efisien biaya. Salah satu metode yang memiliki kriteria tersebut adalah spektrofotometer UV-Vis. Rentan panjang gelombang yang lebar akan mampu mendapatkan panjang gelombang maksimal untuk analisis vitamin B6. Pemilihan panjang gelombang maksimal tunggal untuk vitamin B6 akan mampu memisahkan dengan komponen lain yaitu vitamin B1 dan B6 meskipun ketiganya sama-sama larut dalam air. Hal ini juga menunjukkan bahwa analisis vitamin B6 menggunakan spektrofometri UV Vis juga selektif. Metode : Kondisi optimal analisis vitamin B6 pada sampel vitamin neurotropic adalah menggunakan spektrofotometri UV-Vis pada panjang gelombang 325 nm. Pelarut yang digunakan adalah air. Hasil kurva kalibrasi pada seri kadar 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 110 ppm, 120 ppm dan 130 ppm memiliki nilai r 0,9965. Hasil : Penetapan kadar vitamin B6 menggunakan sampel sediaan multivitamin neurotropik yang dilakukan pada 3 merk. Kadar teoritis yang diukur adalah 100 ppm, sedangkan perolehan kembali pada sampel multivitamin neurotropic merk A masing-masing adalah 98,24 ppm, 95 ppm dan 95,78 ppm dengan nilai standar deviasi (SD) sebesar 1,69. Kadar teoritis vitamin B6 pada sampel multivitamin neurotropik merk B adalah 100 ppm, sedangkan perolehan kembali masing-masing adalah 99 ppm, 102 ppm dan 98 ppm dengan nilai standar deviasi (SD) sebesar 1,15. Penetapan kadar vitamin B6 pada multivitamin neurotropic merk C kadar teoritis yang diukur adalah 100 ppm, sedangkan perolehan kembali masing-masing adalah 102 ppm, 101 ppm dan 99 ppm dengan nilai standar deviasi (SD) sebesar 1,53. Perolehan kembali penetapan kadar vitamin B6 telah sesuai dengan persyaratan AOAC, yaitu untuk kadar analit 100 ppm % recoverinya 90-107%. Nilai SD dari ketiga sampel multivitamin neurotropik yang kurang dari 2 menunjukkan bahwa hasil penetapan kadar vitamin B6 dapat diterima. Kesimpulan : Hasil penelitian ini menunjukkan bahwa vitamin B6 dalam sampel multivitamin neurotropik dapat dianalisis menggunakan spektrofotometri UV-VIS pada panjang gelombang 325 nm menggunakan pelarut ai
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
ANTIBACTERIAL ACTIVITY OF MANGOSTEEN BARK FRACTION (GARCINIA MANGOSTANA L.) SALMONELLA TYPHI ATCC 13311
Get PDFBackground: Typhoid fever is caused by Salmonella typhi bacterial infection which spreads via the faecal-oral route and has epidemic potential. Salmonella typhi is a Gram-negative bacterium in the Enterobacteriaceae family. Currently, the use of natural ingredients can be an alternative treatment for typhoid fever, one of which is the mangosteen stem skin (Garcinia mangostana L.). Purpose: To determine the antibacterial activity of mangosteen stem skin fraction against Salmonella typhi ATCC 13311. Method:The maceration method was selected using methanol solvent and fractionation by ECC using ethyl acetate and n-hexane as solvents. This study used five treatments (fraction with a concentration of 20%, 40%, 80%, chloramphenicol 30µg as a positive control, and DMSO as a negative control) which tested their antibacterial activity against Salmonella typhi ATCC 13311 by disc diffusion. Result: The results showed that the ethyl acetate fraction of mangosteen stem skin had the greatest average inhibition zone, that is 13.86 ± 0.72 mm compared to the n-hexane fraction of mangosteen stem skin with an inhibition zone of 10.43 ± 0.73 mm. The data obtained were then analyzed with One-way ANOVA. Conclusion: The results obtained were p=0.000 (sig <0.05), indicating that there was a significant difference between the ethyl acetate fraction and the n-hexane fraction with 20%, 60%, and 80% concentrations with positive contro
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