1,720,996 research outputs found
LANDASAN ILMIAH BIOSINTESIS SENYAWA BIOPOLIMER POLI (3-HIDROKSIBUTIRAT) DI DALAM SEL BAKTERI Erwinia sp. USMI-20 DARI BAHAN DASAR MINYAK KELAPA SAWIT
Full text linkLandasan ilmiah produksi senyawa biopolimer poli (3-hidroksibutirat) dari minyak kelapa sawit oleh bakteri Erwinia sp. USMI-20 telah dikaji. Kajian dijalankan dengan keadaan fermentasi. Parameter yang diamati berdasarkan kepada pertumbuhan sel, kandungan polimer, konsentrasi polimer, kecepatan pertumbuhan spesifik maksimum, koefisien penghasilan polimer terhadap sumber karbon yang digunakan, Yp(3HB)/C, dan lamanya waktu optimum fermentasi. Granul bioplastik yang dihasilkan di dalam sel Erwinia sp. USMI-20 setelah pengkulturan, diamati dibawah mikroskop elektron transmisi. Hasil percobaan menunjukkan bahwa dengan menggunakan minyak kelapa sawit sebagai sumber karbon tunggal, Erwinia sp. USMI-20 dapat menghasilkan homopolimer P(3HB) dengan kandungan polimer maksimum 59 % dari berat kering selnya, konsentrasi polimer 54.1 g/l dan berat kering sel 6 g/l. P(3HB) dihasilkan dengan kadar pertumbuhan spesifik maksimum 0.3/j, kadar penghasilan polimer spesifik maksimum 0.03/j, Yp(3HB)/C 0.53 g/g dan waktu optimum fermentasi adalah 48 jam. Granul P(3HB) di dalam sel Erwinia sp. USMI-20 dengan diameter granul terletak di antara 100 hingga 350 nm dengan bilangan granul 3-8 granul setiap sel. Granul yang dihasilkan umumnya berbentuk bulat atau bulat lonjong dan berwarna putih.Mekanisme biosintesis P(3HB) dari sumber karbon minyak kelapa sawit oleh Erwinia sp. USMI-20, diperkirakan berasaskan kepada reaksi enzim lipase ekstra-sel terhadap trigliserida dan memasuki siklus -oksidasi asam lekam yang menghasilkan asetil-KoA. Dari asetil Ko-A selanjutnya akan mengikuti laluan biosintesis P(3HB) sehingga menghasilkan poli(3-hidroksibutirat)
Oksitosin Menghambat Aktivasi Ghrelin terhadap Neuron NPY di Pusat Pengendali Makan Arcuate Nucleus Hipotalamus
Full text linkHormon ghrelin disekresikan oleh lambung saat kosong dan dapat mengaktivasi neuron oreksigenik neuropeptida Y (NPY) pada pusat pengendali makan arcuate nucleus (ARC) di hipotalamus. Aktivasi NPY oleh ghrelin menjadi mekanisme utama munculnya rasa lapar secara akut dan resiko obesitas. Di sisi lain, oksitosin dapat mengaktivasi neuron anoreksigenik proopiomelanocortin (POMC) di ARC sehingga bermanifestasi terhadap timbulnya rasa kenyang. Akan tetapi, belum diketahui apakah oksitosin juga dapat mengintervensi aktivasi ghrelin terhadap neuron NPY. Pada penelitian ini, neuron tunggal NPY diisolasi dari hipotalamus tikus putih Wistar jantan dengan metode enzimatis. Dinamika konsentrasi Ca2+ sitosolik ([Ca2+]i) neuron NPY sebagai indikator responnya terhadap ghrelin dan oksitosin dimonitor dengan mikrofluorometri fura-2 in vitro. Inervasi terminal akson oksitosin pada neuron NPY juga diamati secara mikroskopis pada mencit transgenik hrGFP-NPY. Hasil penelitian menunjukkan bahwa oksitosin dapat menghambat peningkatan [Ca2+]i neuron NPY yang diinduksi oleh ghrelin. Sebanyak 33% dari neuron NPY yang teraktivasi oleh ghrelin dapat ditekan oleh oksitosin. Pada observasi mikroskopis ditemukan bahwa terminal-terminal akson neuron oksitosin menginervasi badan sel neuron NPY. Berdasarkan hasil tersebut disimpulkan bahwa oksitosin secara humoral dan neuronal dapat menghambat aktivasi ghrelin terhadap NPY. Hal ini diduga sebagai salah satu mekanisme kerja oksitosin dalam meregulasi makan selain melalui jalur aktivasi neuron POMC di ARC
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
Uji Antimikroba Curcuma spp. Terhadap Pertumbuhan Candida albicans, Staphylococcus aureus dan Escherichia coli
Full text linkA study about the effect of fresh extract of Curcuma spp on the growth of Candida albicans, Staphylococcus aureus and Escherichia coli was conducted from March to July 2012 at Microbiology Laboratory, Faculty of Sciences Andalas University. This experiment used nested completely randommized design. The result showed that fresh extracts of Curcuma spp. have different growth inhibition effects on C. albicans, S. aureus dan E. Coli. Temulawak (Curcuma xhantorrhiza) has the highest inhibition effect to the growth of C. albicans (13.07 mm), S. aureus (15.75 mm) and E. coli (31.56 mm). The lowest bactericidal consentration of fresh extract rhizome of temulawak for E. coli were 12.5% and 25%, but there is no inhibition effect to the C. albicans and S. aureus.Keywords: Curcuma, antimicrobial, extract, pathogen microbia
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
Penapisan Bakteri Termo-Amilolitik Dari Sumber Air Panas Sungai Medang, Kerinci, Jambi
Full text linkThis study aimed to observe the ability of isolated bacteria from Sungai Medang hot spring in producing amylase and to determine the activity and characteristic of isolated amylolytic bacteria which gave the highest amylolytic index. The water samples were collectied by using purposive sampling based on different level of temperatures. This study has successfully collected 48 bacterial isolated from the hot spring. To find the highest amylolytic activity, we tested ten isolated bacteria which have high amylolytic indices. We found that MV2.7 isolated from 740C of hot spring gave the highest amylolytic activity. The isolated bacteria was positive proteolytic, cellulolytic and negative lipolytic. The isolated bacteria showed higher and more spesific activity on rice starch rather than corn and sago starchKeywords: Screening, thermophilic, amylolytic, activit
- …
