PEMBUATAN BIODIESEL DARI ALGA Nannochloropsis sp

Kebutuhan dunia akan minyak bumi semakin hari semakin meningkat Akan tetapi hal tersebut bertolak belakang dengan persediaan minyak bumi yang ada. Oleh karma itu, pada saat ini para peneliti dunia sedang gencar-gencarnya melakukan penelitian ten-tang bio-fuel. Bio-fvel ini digolongkan dalam berbagai jenis, salah satunya adalah biodiesel. Bahan bakar biodiesel adalah metil atau etil ester yang diperoleh dari bermacam-macam sumber energi yang dapat diperbaharui, seperti minyak- tumbuhan atau lemak hewan. Penelitian ini bertujuan untuk- mempelajari pengaruh suhu reaksi (45°C, 55°C, 65°C) dan jenis katalis (KOH, NaOH dan. campuran I= dengan NaOH) dalam pembuatan biodiesel dan minyak alga dengan metode transesterifikasi, Berta mempelajari karakteristik biodiesel (flash point, cetane number, densitas, dan visk-ositas) yang d1hasilk-an pada yield yang terbesar. Hasil penelitian menunjukkan bahwa yield biodiesel terbesar didapatkan pada saat katalis yang digunakan adalah KOH don pada .suhu operasi 65°C yaitu sebesar 75,12% Hasil analisa pada yield biodiesel yang terbesar diperoleh data sebagai berikut flash point 120°C, cetane number 55, densitas 0, 88g/cm3 dan viskositas, 4 cP. Kata Kunci: biodiesel, alga, Nannochloropsis sp, transesterifikas

Towards a structural understanding of the fibrillization pathway in Machado-Joseph’s disease: trapping early oligomers of non-expanded ataxin-3

Machado-Joseph’s disease is caused by a CAG trinucleotide repeat expansion that is translated into an abnormally long polyglutamine tract in the protein ataxin-3. Except for the polyglutamine region, proteins associated with polyglutamine diseases are unrelated, and for all of these diseases aggregates containing these proteins are the major components of the nuclear proteinaceous deposits found in the brain. Aggregates of the expanded proteins display amyloid-like morphological and biophysical properties. Human ataxin-3 containing a non-pathological number of glutamine residues (14Q), as well as its Caenorhabditis elegans (1Q) orthologue, showed a high tendency towards self-interaction and aggregation, under nearphysiological conditions. In order to understand the discrete steps in the assembly process leading to ataxin-3 oligomerization, we have separated chromatographically high molecular mass oligomers as well as medium mass multimers of non-expanded ataxin-3. We show that: (a) oligomerization occurs independently of the poly(Q)-repeat and it is accompanied by an increase in b-structure; and (b) the first intermediate in the oligomerization pathway is a Josephin domain-mediated dimer of ataxin- 3. Furthermore, non-expanded ataxin-3 oligomers are recognized by a specific antibody that targets a conformational epitope present in soluble cytotoxic species found in the fibrillization pathway of expanded polyglutamine proteins and other amyloid-forming proteins. Imaging of the oligomeric forms of the non-pathological protein using electron microscopy reveals globular particles, as well as short chains of such particles that likely mimic the initial stages in the fibrillogenesis pathway occurring in the polyglutamine-expanded protein. Thus, they constitute potential targets for therapeutic approaches in Machado-Joseph’s disease, as well as valuable diagnostic markers in disease settings

Novel insights into chromosome evolution in birds, archosaurs, and reptiles

Homologous synteny blocks (HSBs) and evolutionary breakpoint regions (EBRs) in mammalian chromosomes are enriched for distinct DNA features, contributing to distinct phenotypes. To reveal HSB and EBR roles in avian evolution, we performed a sequence-based comparison of 21 avian and 5 outgroup species using recently sequenced genomes across the avian family tree and a newly-developed algorithm. We identified EBRs and HSBs in ancestral bird, archosaurian (bird, crocodile, and dinosaur), and reptile chromosomes. Genes involved in the regulation of gene expression and biosynthetic processes were preferably located in HSBs, including for example, avian-specific HSBs enriched for genes involved in limb development. Within birds, some lineage-specific EBRs rearranged genes were related to distinct phenotypes, such as forebrain development in parrots. Our findings provide novel evolutionary insights into genome evolution in birds, particularly on how chromosome rearrangements likely contributed to the formation of novel phenotypes

Construindo saberes da mediação na educação em museus de ciências: o caso dos mediadores do museu de astronomia e ciências afins/ Brasil

Nos museus, às atribuições de preservação e estudo de seus acervos, tornou-se indispensável acrescentar a exploração educativa do seu conjunto  material e simbólico. Assim, profissionais capazes de fazer a mediação entre o museu e seu público se tornam figuras importantes. Considera-se que a mediação requer um saber com dimensões peculiares: o saber da mediação. O presente trabalho apresenta resultados relativos ao saber da mediação de duas mediadoras do Museu de Astronomia e Ciências Afins, situado na cidade do Rio de Janeiro, Brasil. Tomando o paradigma do profissional reflexivo, o trabalho tem como objetivo principal conhecer as diferentes dimensões do saber da mediação na complexidade de museus  de ciência e tecnologia, incluindo formas de complementariedade entre ações educativas formais e não formais. São sugeridas estratégias para a formação de mediadores

Impact of Integrase Inhibitors on Cardiovascular Disease Events in People With Human Immunodeficiency Virus Starting Antiretroviral Therapy

BACKGROUND Integrase strand transfer inhibitors (INSTIs) have been associated with an increased risk for cardiovascular disease (CVD) events. We investigated the impact of starting INSTI-based antiretroviral therapy (ART) on CVD events among treatment-naïve people with human immunodeficiency virus using a target trial framework, which reduces the potential for confounding and selection bias. METHODS We included Swiss HIV Cohort Study participants who were ART-naïve after May 2008, when INSTIs became available in Switzerland. Individuals were categorized according to their first ART regimen (INSTI vs other ART) and were followed from ART start until the first of CVD event (myocardial infarction, stroke, or invasive cardiovascular procedure), loss to follow-up, death, or last cohort visit. We calculated hazard ratios and risk differences using pooled logistic regression models with inverse probability of treatment and censoring weights. RESULTS Of 5362 participants (median age 38 years, 21% women, 15% of African origin), 1837 (34.3%) started INSTI-based ART, and 3525 (65.7%) started other ART. Within 4.9 years (interquartile range, 2.4-7.4), 116 CVD events occurred. Starting INSTI-based ART was not associated with an increased risk for CVD events (adjusted hazard ratio, 0.80; 95% confidence interval [CI], .46-1.39). Adjusted risk differences between individuals who started INSTIs and those who started other ART were -0.17% (95% CI, -.37 to .19) after 1 year, -0.61% (-1.54 to 0.22) after 5 years, and -0.71% (-2.16 to 0.94) after 8 years. CONCLUSIONS In this target trial emulation, we found no difference in short- or long-term risk for CVD events between treatment-naïve people with human immunodeficiency virus who started INSTI-based ART and those on other ART