Uji Toksisitas Dengan Metode BSLT Dan Analisis Kandungan Fitokimia Ekstrak Daun Soyogik (Saurauia Bracteosa DC) Dengan Metode Soxhletasi

Penelitian ini bertujuan untuk mengetahui toksisitas dari ekstrak daun soyogik menggunakan metode Brine Shrimp Lethality Test (BSLT) dan menentukan kandungan fitokimia daun soyogik (Saurauia bracteosa DC). Ekstrak dibuat dengan cara soxhletasi menggunakan pelarut metanol. Uji toksisitas dilakukan dengan menggunakan larva udang Artemia salina Leach yang berumur 48 jam. Efek toksik ekstrak diidentifikasi dengan presentase kematian larva udang menggunakan analisis probit (LC50). Kandungan fitokimia meliputi fenolik, flavonoid dan tanin. Penelitian menunjukkan ekstrak daun soyogik bersifat toksik (LC50: 35,4 ppm). Kandungan senyawa fenolik (128 ppm), flavonoid (44,4 ppm), tanin (86,75 ppm).The aims of this research were to determine the toxicity of soyogik (Saurauia bracteosa DC)leaf extract using Brine Shrimp Lethality Test (BSLT) and the content of its compounds. The extraction was carried out ​​by soxhletation using methanol. Toxicity assay used Artemia salina Leach larvae of 48-hours age. Toxic effects of the extract were identified by the percentage mortality of shrimp larvae using probit analysis (LC50). Leaf extract was furthertested to phenolic, flavonoid and tannin contents. The results showed soyogik leaf extract was toxic (LC50: 35,4 ppm). The content of phenolic, flavonoid, and tannin compounds were 128 ppm, 44,4 ppm and 86,75 ppm, respectively

Is Scotland a Westminster-style Majoritarian Democracy or a Scandinavian-style Consensus Democracy? A Comparison of Scotland, the UK and Sweden

Peer reviewedPostprin

Lecturers’ perceptions: the value of assessment rubrics for informing teaching practice and curriculum review and development

http://dx.doi.org/10.1080/18146627.2015.1110907The assessment rubric is increasingly gaining recognition as a valuable tool in teaching and learning in higher education. While many studies have examined the value of rubrics for students, research into the lecturers’ usage of rubrics is limited. This article explores the lecturers’ perceptions of rubrics, in particular, its use and design, the role it can play in informing one's teaching practice and in curriculum review and development. The data shows that many lecturers use the rubric in a very mechanical and unconscious manner and view it mostly as a grading tool with limited instructional value. While acknowledging the rubric as a reflective tool for students, lecturers do not perceive it as having the same benefits for them. The findings, therefore suggest more conversations around the role that rubrics can play in informing one's teaching practice and course design. It also suggests further research into this area.Web of Scienc

Boundary Limitation of Wavenumbers in Taylor-Vortex Flow

We report experimental results for a boundary-mediated wavenumber-adjustment mechanism and for a boundary-limited wavenumber-band of Taylor-vortex flow (TVF). The system consists of fluid contained between two concentric cylinders with the inner one rotating at an angular frequency $\Omega$. As observed previously, the Eckhaus instability (a bulk instability) is observed and limits the stable wavenumber band when the system is terminated axially by two rigid, non-rotating plates. The band width is then of order $\epsilon^{1/2}$ at small $\epsilon$ ($\epsilon \equiv \Omega/\Omega_c - 1$) and agrees well with calculations based on the equations of motion over a wide $\epsilon$-range. When the cylinder axis is vertical and the upper liquid surface is free (i.e. an air-liquid interface), vortices can be generated or expelled at the free surface because there the phase of the structure is only weakly pinned. The band of wavenumbers over which Taylor-vortex flow exists is then more narrow than the stable band limited by the Eckhaus instability. At small $\epsilon$ the boundary-mediated band-width is linear in $\epsilon$. These results are qualitatively consistent with theoretical predictions, but to our knowledge a quantitative calculation for TVF with a free surface does not exist.Comment: 8 pages incl. 9 eps figures bitmap version of Fig

Rapid Structural, Kinetic, and Immunochemical Analysis of Alpha-Synuclein Oligomers in Solution.

Oligomers comprised of misfolded proteins are implicated as neurotoxins in the pathogenesis of protein misfolding conditions such as Parkinson's and Alzheimer's diseases. Structural, biophysical, and biochemical characterization of these nanoscale protein assemblies is key to understanding their pathology and the design of therapeutic interventions, yet it is challenging due to their heterogeneous, transient nature and low relative abundance in complex mixtures. Here, we demonstrate separation of heterogeneous populations of oligomeric α-synuclein, a protein central to the pathology of Parkinson's disease, in solution using microfluidic free-flow electrophoresis. We characterize nanoscale structural heterogeneity of transient oligomers on a time scale of seconds, at least 2 orders of magnitude faster than conventional techniques. Furthermore, we utilize our platform to analyze oligomer ζ-potential and probe the immunochemistry of wild-type α-synuclein oligomers. Our findings contribute to an improved characterization of α-synuclein oligomers and demonstrate the application of microchip electrophoresis for the free-solution analysis of biological nanoparticle analytes

Network Rewiring of Homologous Recombination Enzymes during Mitotic Proliferation and Meiosis.

Homologous recombination (HR) is essential for high-fidelity DNA repair during mitotic proliferation and meiosis. Yet, context-specific modifications must tailor the recombination machinery to avoid (mitosis) or enforce (meiosis) the formation of reciprocal exchanges-crossovers-between recombining chromosomes. To obtain molecular insight into how crossover control is achieved, we affinity purified 7 DNA-processing enzymes that channel HR intermediates into crossovers or noncrossovers from vegetative cells or cells undergoing meiosis. Using mass spectrometry, we provide a global characterization of their composition and reveal mitosis- and meiosis-specific modules in the interaction networks. Functional analyses of meiosis-specific interactors of MutLγ-Exo1 identified Rtk1, Caf120, and Chd1 as regulators of crossing-over. Chd1, which transiently associates with Exo1 at the prophase-to-metaphase I transition, enables the formation of MutLγ-dependent crossovers through its conserved ability to bind and displace nucleosomes. Thus, rewiring of the HR network, coupled to chromatin remodeling, promotes context-specific control of the recombination outcome

'This is what democracy looks like' : New Labour's blind spot and peripheral vision

New Labour in government since 1997 has been roundly criticized for not possessing a clear, coherent and consistent democratic vision. The absence of such a grand vision has resulted, from this critical perspective, in an absence of 'joined-up' thinking about democracy in an evolving multi-level state. Tensions have been all too apparent between the government's desire to exert central direction - manifested in its most pathological form as 'control freakery' - and its democratising initiatives derived from 'third-way' obsessions with 'decentralising', 'empowering' and 'enabling'. The purpose of this article is to examine why New Labour displayed such apparently impaired democratic vision and why it appeared incapable of conceiving of democratic reform 'in the round'. This article seeks to explain these apparent paradoxes, however, through utilising the notion of 'macular degeneration'. In this analysis, the perceived democratic blind spot of New Labour at Westminster is connected to a democratic peripheral vision, which has envisaged innovative participatory and decentred initiatives in governance beyond Westminster

Efficient Algorithm on a Non-staggered Mesh for Simulating Rayleigh-Benard Convection in a Box

An efficient semi-implicit second-order-accurate finite-difference method is described for studying incompressible Rayleigh-Benard convection in a box, with sidewalls that are periodic, thermally insulated, or thermally conducting. Operator-splitting and a projection method reduce the algorithm at each time step to the solution of four Helmholtz equations and one Poisson equation, and these are are solved by fast direct methods. The method is numerically stable even though all field values are placed on a single non-staggered mesh commensurate with the boundaries. The efficiency and accuracy of the method are characterized for several representative convection problems.Comment: REVTeX, 30 pages, 5 figure