932 research outputs found

    PELATIHAN KEWIRAUSAHAAN BAGI MAHASISWA PROGRAM STUDI PENDIDIKAN PANCASILA DAN KEWARGANEGARAAN IKIP PGRI PONTIANAK

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    Kegiatan pelatihan ini bertujuan untuk (1) menumbuhkan dan meningkatkan kemampuan, minat mahasiswa untuk menekuni dunia wirausaha, (2) meningkatkan kreativitas berpikir mahasiswa dalam mengembangkan kemampuan wirausaha, (3) membuka wawasan tentang perkembangan dunia wirausaha di Kalimantan Barat, dan (4) memberikan motivasi kepada dosen dan mahasiswa untuk dapat berpartisipasi dalam mengembangkan dunia wirausaha di Kalimantan Barat. Selain itu, kegiatan ini diharapkan akan memberikan manfaat pada peningkatan kemampuan, minat, motivasi, inovasi, dan kreativitas mahasiswa untuk menekuni dunia wirausaha, meningkatnya kreativitas berpikir mahasiswa dalam mengembangkan kemampuan wirausaha, membuka wawasan tentang perkembangan dunia wirausaha di Kalimantan Barat, dan mendorong motivasi kepada dosen dan mahasiswa untuk dapat berpartisipasi dalam mengembangkan dunia wirausaha di Kalimantan Barat. Peserta kegiatan pelatihan kewirausahaan adalah mahasiswa Prodi PPKn di IKIP PGRI Pontianak terdiri dari 40 orang. Tempat kegiatan yaitu Balai Pertemuan Desa Sungai Baru Kecamatan Telok Keramat Kabupaten Sambas. Pengenalan terhadap dunia dan peluang usaha tentunya akan memungkinkan peningkatan motivasi individu bahwa upaya kewirausahaan akan memberikan hasil yang jauh lebih baik daripada hanya duduk menunggu peluang mejadi orang yang bekerja diperkantora

    Synthesis and characterization of polystyrene-blockpoly(vinylbenzoic acid): a promising compound for manipulating photoresponsive properties at the nanoscale

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    "Published online: 27 January 2015"Using reversible addition-fragmentation chain transfer (RAFT) polymerization, the effect of PSt macroRAFT and 4VBA ratio on the synthesis of a carboxylic acid functional block copolymer (PSt-b-P4VBA) was studied. PSt macroRAFT polymer was initially prepared followed by the insertion of 4-vinylbenzoic acid (4VBA) monomer. The chemical structure of the diblock copolymer was confirmed by NMR and FTIR. The effect of PSt macroRAFT and 4VBA ratio on copolymerization yield and on molecular weight distribution was assessed by gel permeation chromatography. The rate of polymerization did not change as the 4VBA/PSt macroRAFT ratio increased, indicating an ideal amount of 4VBA insertion. An optimal ratio of [PSt macroRAFT]:[AIBN]:[4VBA] was 1.2:1:180. DSC and XRD confirmed the amorphous structure of homo and copolymer. Thermal stability was higher for PSt-b-P4VBA forming activated porous carbon char by dehydration, carbonization and oxidation. SEM and STEM observations showed a morphological evolution between PSt macroRAFT and the correspondent copolymer.The authors acknowledge the n-STeP-Nanostructured systems for Tailored Performance, with reference NORTE-07-0124-FEDER-000039, supported by the Programa Operacional Regional do Norte (ON.2), PEst-C/CTM/LA0025/2013 (Strategic Project-LA 25-2013-2014)

    Discrete and Stereospecific Oligomers Prepared by Sequential and Alternating Single Unit Monomer Insertion

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    Natural biopolymers, such as DNA and proteins, have uniform microstructures with defined molecular weight, precise monomer sequence, and stereoregularity along the polymer main chain that affords them unique biological functions. To reproduce such structurally perfect polymers and understand the mechanism of specific functions through chemical approaches, researchers have proposed using synthetic polymers as an alternative due to their broad chemical diversity and relatively simple manipulation. Herein, we report a new methodology to prepare sequence-controlled and stereospecific oligomers using alternating radical chain growth and sequential photoinduced RAFT single unit monomer insertion (photo-RAFT SUMI). Two families of cyclic monomers, the indenes and the N-substituted maleimides, can be alternatively inserted into RAFT agents, one unit at a time, allowing the monomer sequence to be controlled through sequential and alternating monomer addition. Importantly, the stereochemistry of cyclic monomer insertion into the RAFT agents is found to be trans-selective along the main chains due to steric hindrance from the repeating monomer units. All investigated cyclic monomers provide such trans-selectivity, but analogous acyclic monomers give a mixed cis- and trans-insertion

    Cerebral Arteriovenous Malformations (cAVMs): What Is New?

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    Cerebral arteriovenous malformations (cAVMs) are rare congenital anomalies of cerebral blood vessels that result from maldevelopment of the capillary bed, permitting direct communication between cerebral arteries and veins. It usually occurs in the supratentorial area of the brain; however, it can occur anywhere in the brain and spinal cord. Most of the patients with cAVMs present with a variety of complaints such as seizures, intracerebral hemorrhage, headache, and progressive focal neurological deficit. Imaging such as CT, MRI, and angiography plays a vital role in diagnosis, grading, risk assessment, and posttherapeutic follow-up. The multidisciplinary team use three therapeutic modalities in the treatment of cAVMs. This chapter reviews the clinical presentations, diagnosis, classification, and treatment of cAVMs

    The effect of Z-group modification on the RAFT polymerization of N-vinylpyrrolidone controlled by "switchable" N-pyridyl-functional dithiocarbamates

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    This is an accepted manuscript of an article published by Royal Society of Chemistry in the Polymer Chemistry on 24/08/2015, available online: https://doi.org/10.1039/C5PY01021G The accepted version of the publication may differ from the final published version.The ability of a RAFT agent to control the polymerization of a monomer is dictated by the structures of both the monomer and the RAFT agent. In this paper, the polymerization of N-vinylpyrrolidone was examined with a series of cyanomethyl N-aryl-N-pyridyldithiocarbamates [(4-R′Ph)N(py)C(S)SCH2CN] varying in the substituent (R′) at the 4-position on the phenyl ring. The polymerization of N-vinylpyrrolidone was best controlled when R′ was methoxy; one of the least active RAFT agents in the series. The preservation of RAFT agent functionality was demonstrated by chain extension experiments with further N-vinylpyrrolidone. Again best control again was found for the RAFT agent with R′ = MeOPh. The utility of this RAFT agent was also proved with the preparation of poly(N-isopropylacrylamide)-block-poly(N-vinylpyrrolidone).The authors gratefully acknowledge the Australian Government for award of an Australian Postgraduate Award to S.J.S., the CSIRO Manufacturing Flagship and the School of Science and Technology at the University of New England for project funding.Published versio

    A Rheometry Method to Assess The Evaporation-Induced Mechanical Strength Development of Polymer Solutions Used For Membrane Applications

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    Rotational and oscillatory shear rheometry were used to quantify the flow behavior under minimal and significant solvent evaporation conditions for polymer solutions used to fabricate isoporous asymmetric membranes by the self-assembly and non-solvent induced phase separation (SNIPS) method. Three different A-B-C triblock terpolymer chemistries of similar molar mass were evaluated: polyisoprene-^-polystyrene-6-poly(4-vinylpyridine) (ISV); polyisoprene-6- polystyrene-6-poly(V,A-dimethylacrylamide) (ISD); and polyisoprene-Z\u3e-polystyrene-h-poly(fer/- butyl methacrylate) (ISB). Solvent evaporation resulted in the formation of a viscoelastic film typical of asymmetric membranes. Solution viscosity and film viscoelasticity were strongly dependent on the chemical structure of the triblock terpolymer molecules. A hierarchical magnitude (ISV\u3eISB\u3eISD) was observed for both properties, with ISV solutions displaying the greatest solution viscosity, fastest film strength development, and greatest strength magnitude

    Chain transfer kinetics of acid/base switchable n-aryl- n-pyridyl dithiocarbamate RAFT agents in methyl acrylate, n-vinylcarbazole and vinyl acetate polymerization

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    This is an accepted manuscript of an article published by American Chemistry Society in Macromolecules on 14/05/2012, available online: https://doi.org/10.1021/ma300616g ©American Chemical Society. The accepted version of the publication may differ from the final published version.The structures of the "Z" and "R" substituents of a RAFT agent (Z-C(S)S-R) determine a RAFT agent's ability to control radical polymerization. In this paper we report new acid/base switchable N-aryl-N-pyridyl dithiocarbamates (R = -CH 2CN, Z = -N(Py)(Ar)) which vary in substituent at the 4-position of the aryl ring and the use of these to control molecular weight and dispersity. In their protonated form, the new RAFT agents are more effective in controlling polymerization of the more activated monomer, methyl acrylate (MA), whereas in their neutral form they provide more effective control of the polymerization of less activated monomers, N-vinyl carbazole (NVC) and vinyl acetate (VAc). For each polymerization, the apparent chain transfer coefficient (C trapp) shows a good correlation with Hammett parameters. Dithiocarbamates with more electron-withdrawing aryl ring substituents have the higher C trapp. This demonstrates the influence of polar effects on C trapp and supports the hypothesis that the activity of these RAFT agents is determined by the availability of the lone pair of the dithiocarbamate nitrogen.The authors gratefully acknowledge the Capability Development Fund of CSIRO Materials Science and Engineering for financial support.Published versio
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