82 research outputs found

    Model Pembelajaran Asam Basa Berbasis Scs (Science Process Skills) Melalui Kegiatan Laboratorium Sebagai Wahana Pendidikan Sains Siswa Mts

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    Tujuan penelitian ini adalah untuk memperkenal- kan dan mengetahui efektivitas Model Pembelajaran SCS ( Science Process Skills ) melalui kegiatan Laboratorium Sebagai Wahana Pendidikan Sains yang cocok bagi siswa MTs agar meningkatkan: penguasaan konsep kimia, ke- mampuan berpikir kreatif, dan keterampilan sains siswa. Metode yang digunakan adalah metode penelitian kelas, dan difokuskan pada pokok bahasan asam basa. Penelitian ini dilakukan di salah satu MTs Negeri di kota Semarang dengan subyek sebanyak 40 siswa kelas III. Instrumen yang digunakan dalam penelitian ini meliputi model pembelaja- ran, soal-soal tes, pedoman wawancara, pedoman obser- vasi dan angket, sedang LKS digunakan pada saat kegiatan laboratorium. Dalam model pembelajaran dikembangkan empat jenis konsep yaitu konsep kongkret, konsep yang menyatakan sifat, konsep yang melibatkan penggambaran simbol, dan konsep berdasarkan prinsip. Model pembela- jaran ini dapat meningkatkan pemahaman konsep pada setiap kelompok kemampuan siswa, mengembangkan ke- mampuan berpikir kreatif dengan hasil tertinggi pada as- pek membangun konsep di atas pengetahuan yang telah ada pada diri siswa dan terendah pada aspek memilih hal- hal yang mungkin tidak relevan, serta keterampilan sains mengatasi kurangnya waktu pembelajaran, bagian-bagian pembelajaran tertentu dapat dilaksanakan di luar jam ke- las

    Thermostabilization by the Improvement of Intertrimeric Residues in Thermus thermophilus Inorganic Pyrophosphatase.

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    Inorganic pyrophosphatase (EC. 3.6.1.1) from Thermus thermophilus (Tth PPase)is a thermostable homohexamer of 174 amino acids,and its intertrimer interface is formed mainly by the symmetric α-helix A between subunits. Amino acids and their interactions composing intertrimer interface are different in hexameric Family I PPases,and then it was deduced that Tth PPase showed high thermostability because of stabilizing this interface by interactions of these residues. In this study,we focused on Thr138 and Ala141 residues in intertrimer interface of Tth PPase to confirm the relationship between intertrimeric residues and thermostability, and then improved their combination to His and Asp/Glu (HD or HE variant). As results,the HD variant showed the highest thermostability of enzyme activity,fluorescence spectra, and quaternary structure in the wild type Tth PPase and all variants. Especially,about 38% of hexamer and almost 40% of enzyme activity were observed in HD variant after heating even at 85℃. Therefore,we suggested that the conversion to a set of ionic His138 and Asp141 at intertrimer interface had increased the thermostability of Tth PPase,and then suppressed its thermal aggregation

    Hybrid nanoarchitecturing of hierarchical zinc oxide wool-ball-like nanostructures with multi-walled carbon nanotubes for achieving sensitive and selective detection of sulfur dioxide

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    This work reports a facile glycerol-assisted solvothermal method for synthesizing hierarchical three-dimensional (3D) wool-ball-like zinc oxide (ZnO) nano structures and their subsequent modifications with multi-walled carbon nanotubes (MWCNTs) as modifiers for achieving sensitive and selective detection of toxic sulfur dioxide (SO2) gas. Structurally, the as-synthesized 3D wool-ball-like ZnO is assembled of two-dimensional (2D) plate-like structures, which themselves are arranged by numerous small nanopartides. Furthermore, in this work we observed an interesting new phenomenon in which when a high concentration of MWCNTs is introduced, many small nanorods grew on the surface of the plate-like structures which assemble the 3D wool-ball-like ZnO nanostructures. When evaluated for SO2 detection, the ZnO/MWCNTs (10:1) composite (ZnO:MWCNTs =10:1) shows a high response of 220.8 to 70 ppm of SO2 gas (approximately three times higher than the response of pure wool-ball-like ZnO) at an optimum operating temperature of 300 degrees C. Additionally, the composite also displays good stability and selectivity to SO2 with the response to 50 ppm of SO2 being 7-14 times higher than the responses to other tested gases at a similar concentration. The excellent sensing performance of the wool-ball-like ZnO/MWCNTs (10:1) composite is mainly attributed to: (i) the formation of p-n heterojunctions at the ZnO/MWCNTs interfaces, which greatly enhance the resistance changes upon exposure to SO2 gas and (ii) the increased amount of adsorption sites for O-2 and SO2 gas molecules owing to the larger surface area of the composite and defects sites generated by the functionalization process of MWCNTs. (C) 2018 Elsevier B.V. All rights reserved

    Effect of Cys168 substitutions on the Thermostability and the Thermal Aggregation of Thermus thermophilus Inorganic Pyrophosphatase.

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    Thermus thermophilus Inorganic pyrophosphatase (Tth PPase) is comprised of homohexamer,and exhibits high thermostability. However,the thermal aggregation containing the cross-linked dimer was observed after heating above 85℃. Therefore,we focused on the sole cysteine (Cys168) in C-terminalregion,and evaluated the effects of substitutions at this position on thermostability and thermal aggregation of Tth PPase. Firstly,we prepared the four Cys168-substituted variants (C168A,L ,1,and F) by site-directed mutagenesis. Although all variants formed hexamer in native state,C168A variant exhibited the highest thermostabilities for the enzyme activity and quatemary structure in wild type and all variants,while the other variants decreased them drastically as the side chain at the 168 position was much more bulky and hydrophobic in Tth PPase. Moreover, suppression of thermal aggregation for C168A variant was observed in the ANS fluorescence experiments. Therefore,we suggest that the small volume and less hydrophobicity of side chain at 168 position may contribute to the conformational thermostability, and substitution with Ala is the most suitable for thermostabilization and suppression ofthermal aggregation of Tth PPase

    The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016)

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    Background and purposeThe Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in February 2017 and published in the Journal of JSICM, [2017; Volume 24 (supplement 2)] https://doi.org/10.3918/jsicm.24S0001 and Journal of Japanese Association for Acute Medicine [2017; Volume 28, (supplement 1)] http://onlinelibrary.wiley.com/doi/10.1002/jja2.2017.28.issue-S1/issuetoc.This abridged English edition of the J-SSCG 2016 was produced with permission from the Japanese Association of Acute Medicine and the Japanese Society for Intensive Care Medicine.MethodsMembers of the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine were selected and organized into 19 committee members and 52 working group members. The guidelines were prepared in accordance with the Medical Information Network Distribution Service (Minds) creation procedures. The Academic Guidelines Promotion Team was organized to oversee and provide academic support to the respective activities allocated to each Guideline Creation Team. To improve quality assurance and workflow transparency, a mutual peer review system was established, and discussions within each team were open to the public. Public comments were collected once after the initial formulation of a clinical question (CQ) and twice during the review of the final draft. Recommendations were determined to have been adopted after obtaining support from a two-thirds (> 66.6%) majority vote of each of the 19 committee members.ResultsA total of 87 CQs were selected among 19 clinical areas, including pediatric topics and several other important areas not covered in the first edition of the Japanese guidelines (J-SSCG 2012). The approval rate obtained through committee voting, in addition to ratings of the strengths of the recommendation, and its supporting evidence were also added to each recommendation statement. We conducted meta-analyses for 29 CQs. Thirty-seven CQs contained recommendations in the form of an expert consensus due to insufficient evidence. No recommendations were provided for five CQs.ConclusionsBased on the evidence gathered, we were able to formulate Japanese-specific clinical practice guidelines that are tailored to the Japanese context in a highly transparent manner. These guidelines can easily be used not only by specialists, but also by non-specialists, general clinicians, nurses, pharmacists, clinical engineers, and other healthcare professionals

    Strucutral Analysis of Passive Films on Stainless Steel by Synchrotron Radiation

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    Hybrid methylammonium lead halide perovskite nanocrystals confined in gyroidal silica templates

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    We successfully synthesized hybrid methylammonium lead halide nanocrystals confined in a gyroidal mesoporous silica template. The nanocrystals adopted the same crystal structure as their bulk perovskite counterparts, highlighting the ability to control the bandgap by tuning the pore-size of the template. Besides providing more accessible spaces for the materials to diffuse within the channels, the 3D mesh of the gyroidal template should also allow easier escape of the solvent and pinning of the particles at different points, thus promoting the formation of isolated nanoparticles over larger structures (e.g., nanowires, nanorods)

    Coalescence-driven verticality in mesoporous TiO2 thin films with long-range ordering

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    Mesoporous semiconducting films with continuous interconnectivity and minimal tortuosity, such as densely ordered arrays of vertical channels, are ideal for ensuring a maximal surface area at the heterojunction to increase the density of charges or photons. While the design of these films with nanostructures below 50 nm using modern lithography is not feasible, continuously perpendicular pores can be obtained throughout a TiO2 film using a traditional soft-templating approach and lyotropic crystal engineering. We demonstrate here that a polystyrene-b-poly(ethylene oxide) block copolymer in a three-solvent system can self-assemble into a body-centered cubic Im3̅m template. The long-range three-dimensional periodicity of the template combined with a high degree of vertical contraction results in coalescence of the pores into orthogonal channels that are strongly interconnected with their nearest neighbors in the (011̅) plane. This work presents evidence of lateral long-range ordering with continuously transverse vertical porosity in a TiO2 material, which will enable functional applications, such as filtration, sensing, catalysis, and optoelectronics. To this end, we demonstrate the ability of the films to template and host methylammonium lead iodide perovskite nanocrystals
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