1,720,967 research outputs found
Analisis Vitamin B6 (Piridoksin) pada Sediaan Tablet Multivitamin Neurotropik Menggunakan Spektrofotometri UV-Vis
Full text linkVitamin B6 analysis in neurotrophic multivitamin tablet preparations requires a simple, fast and cheap method. UV-Vis spectrophotometer is having these criteria. Vitamin B6 analysis using UV Vis spectrophotometry is very quick so that the substance degradation can be inhibited and the results obtained will be accurate. Selection of single maximum wavelength for vitamin B6 will be able to separate with other components of vitamins B1 and B6 although all three are soluble in water. The optimal condition of vitamin B6 analysis in neurotropic multivitamin samples was using UV-Vis spectrophotometry at 325 nm wavelength. The solvent used is water. The calibration result curve in series of 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 110 ppm, 120 ppm and 130 ppm have r value of 0, 9965. Determination of vitamin B6 levels using three brands of neurotrophic multivitamin samples performed. The measured theoretical level was 100 ppm, whereas the recovery of neurotropic multivitamin A samples were 98.24 ppm, 95 ppm and 95.78 ppm respectively with SD 1.69. The theoretical content of vitamin B6 in the neurotrophic multivitamin sample of B brand was 100 ppm, whereas the recovery was 99 ppm, 102 ppm and 98 ppm with SD 1.15. Determination of vitamin B6 concentration in the neurotropic multivitamin brand C the measured theoretical level was 100 ppm, while the recovery was 102 ppm, 101 ppm and 99 ppm with SD
value of 1.53. The recovery of vitamin B6 level determination has been in accordance with AOAC requirements, ie for 100% ppm% analytical calculation 90-107%. The primary SD values of the three neurotrophic multivitamin samples of less than 2 indicate that vitamin B6 levels are acceptable. The results of this study indicate that vitamin B6 in a neurotrophic multivitamin sample can be analyzed using UV-VIS spectrophotometry at a wavelength of 325 nm using a water solvent
HPLC METHOD DEVELOPMENT AND VALIDATION FOR SIMULTANEOUS ASSAY OF METAMIZOLE, THIAMINE AND PYRIDOXINE IN TABLET
Full text linkThe aim of the present study was develop and validate HPLC method for the simultaneous assay of metamizole, thiamine and pyridoxine in tablet. Metamizole is a substance that is easily hydrolyzed in the presence of water and oxygen. To inhibit the hydrolysis of metamizole during sample preparation prior to HPLC analysis. Sodium sulfite is added and its optimum concentration was investigated. The chromatographic system includes a RP C8(2) column (150x4.6 mm, 5 µm particle size) in conjunction with Photo Diode Array (PDA) detector. The optimal chromatographic condition was obtained using a mobile phase consisting of phosphate buffer 35mM pH 3.0: methanol (80:20), flowrate 1.0 mL/min, and 10 µl injection volume. The metamizole, thiamine and pyridoxine were detected at 275 nm. The hydrolysis of metamizole was successfully inhibited by adding solution containing 1.5 mg/mL sodium sulfite to solvent and 0.5 mg/mL sodium sulfite to mobile phase. The validation results indicate a good specificity and a linear detector responses with r>0.999. The accuracy (% recovery) for metamizole, thiamine and piridoxine were 100.26%; 99.09%; and 100.03%, respectively. The method yields good precision with RSD of metamizole, thiamine and pyridoxine were 2.0912%; 1.4489%; and 0.8418%, respectively. The validated method was successfully applied for simultaneous assay of metamizole, thiamine and pyridoxine in tablet
Aktifitas Sitotoksik Ekstrak Buah Jeruk Pamelo (Citrus Maxima) Terhadap Sel Kanker Servik
No full textKanker servik adalah jenis kanker yang banyak terjadi di Indonesia. Prevalensi terjadinya terus meningkat, sehingga diperlukan alternative terapi bagi penderita kanker serviks. Potensi jeruk pamelo sebagai agen anti kanker serviks karena pada buah ini mengandung senyawa likopen. Likopen bekerja dengan cara menekan proliferasi atau multiplikasi sel. Pada pasien kanker servik terjadi multiplikasi sel yang sangat cepat. Likopen juga mampu memperlambat atau bahkan mencegah proses oksidasi dari molekul lain dan mengeliminasi radikal bebas dalam tubuh yang dapat menyebabkan kerusakan sel. Radikal bebas dapat berikatan terhadap DNA, protein dan lemak dan akan merusak fungsi fisiologisnya, yang pada gilirannya dapat menyebabkan berkembangnya penyakit kanker servik. Likopen merupakan eliminator radikal bebas yang sangat efektif. Melalui dua mekanisme ini yaitu menekan multiplikasi sel dan eliminator radikal bebas maka likopen dapat digunakan sebagai terapi kanker servik.Uji aktivitas sitotoksik ekstrak buah jeruk pamelo dilakukan dengan metode MTT pada sel HeLa. Buah jeruk pamelo diekstrak dengan metode maserasi menggunakan pelarut etanol 96%. Kultur sel kanker servik (sel HeLa)di ditransfer sebanyak 1x104 sel/sumuran dalam media kultur yang terdiri dari FBS, penisilin-sterptomisin, amfoterizin-B sebagai dan RPMI 1640 kedalam 96-well plate dan diinkubasi dalam inkubator CO2 5% semalam. Selanjutnya dilakukan pemberian sampel uji dengan seri kadar dan dibuat replikasi tiga kali (triplo), kemudian diinkubasikan kembali semalam. Pengujian hari ke tiga, penambahan reagen MTT, dan setelah 4 jam akan terbentuk kristal formazan pada sel yang masih hidup. Selanjutnya ditambahkan SDS stoper untuk menghentikan reaksi MTT. Kemudian dilakukan pembacaan absorbansi menggunakan elisa reader pada panjang gelombang 595nm dan dilanjutkan penentuan nilai IC50. Hasil penelitian menunjukkan nilai IC 50 ekstrak jeruk pamelo 10.67 µg/µL. hal ini menunjukkan bahwa ekstrak jeruk pamelo memiliki potensi sebagai agen anti kanker servik yang besar. Penelitian ini dapat memberikan kontribusi pada pengembangan obat kanker servik. Ekstrak buah jeruk pamelo yang selektif terhadap sel kanker dapat menjadi terapi pilihan dalam penanganan pasien kanker servik yang prevalensinya tinggi di Indonesia
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Full text linkWe 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
- …
