281 research outputs found

    ANALISIS KEMAMPUAN BERFIKIR KREATIF MATEMATIS SISWA SMP KELAS VIII PADA MATERI BANGUN RUANG

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    This study aims to examine and analyze the students' creative thinking ability. The population in this study is the students of grade VIII junior high school in one of the schools in Karawang. This classroom action research is planned to consist of 2 (two) cycles. Firstly given initial tests with a view to know the initial ability of students and related to the material wake up space. In the first cycle, the remaining able to answer the problem well reach 36.6%. From the results of tests in the first cycle can be said the ability of creative thinking students is still low.Â

    Dampak Program Gerakan Penerapan Pengelolaan Tanaman Terpadu (Gp-ptt) terhadap Tingkat Penerapan Teknologi Ptt pada USAhatani Jagung (Zea Mays L.) (Studi Kasus Dikelompok Tani Sangkan Hurip Desa Tanjungsari Kecamatan Rajadesa Kabupaten Ciamis)

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    Penelitian ini bertujuan untuk mengetahui : (1) Tingkat Penerapan Teknologi PTT sebelum dan sesudah petani mengikuti program GP-PTT ; (2) Dampak Program GP-PTT Terhadap Tingkat Penerapan Teknologi PTT Pada Usahatani Jagung (Zea mays L.) Jenis penelitian yang digunakan dalam penelitian ini adalah studi kasus di Kelompok Tani Sangkan Hurip Desa Tanjungsari Kecamatan Rajadesa Kabupaten Ciamis. Analisis data untuk mengetahui penerapan teknologi PTT sebelum dan sesudah petani mengikuti Program GP-PTT dianalisis secara deskriptif kualitatif, sedangkan untuk mengetahui Dampak Program GP-PTTTerhadap Tingkat Penerapan Teknologi PTT pada Usahatani Jagung dianalisis menggunakan pendekatan statitiska non parametrik yaitu uji tanda (sign test).Hasil penelitian menunjukkan bahwa : (1) Tingkat Penerapan Teknologi PTT sebelum petani mengikuti program GP-PTT sebanyak 17 orang (42,50) termasuk kategori sedang, sedangkan setelah petani mengikuti Program GP-PTT sebanyak 35 orang (87,50 % termasuk kategori tinggi;(2) Program GP-PTT mempunyai dampak positif yang nyata terhadap penerapan teknologi PTT pada USAhatani jagung di Desa Tanjungsari Kecamatan Rajadesa Kabupaten Ciamis

    In situ structure of the Caulobacter crescentus flagellar motor and visualization of binding of a CheY-homolog

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    Bacterial flagellar motility is controlled by the binding of CheY proteins to the cytoplasmic switch complex of the flagellar motor, resulting in changes in swimming speed or direction. Despite its importance for motor function, structural information about the interaction between effector proteins and the motor are scarce. To address this gap in knowledge, we used electron cryotomography and subtomogram averaging to visualize such interactions inside Caulobacter crescentus cells. In C. crescentus, several CheY homologs regulate motor function for different aspects of the bacterial lifestyle. We used subtomogram averaging to image binding of the CheY family protein CleD to the cytoplasmic Cring switch complex, the control center of the flagellar motor. This unambiguously confirmed the orientation of the motor switch protein FliM and the binding of a member of the CheY protein family to the outside rim of the C ring. We also uncovered previously unknown structural elaborations of the alphaproteobacterial flagellar motor, including two novel periplasmic ring structures, and the stator ring harboring eleven stator units, adding to our growing catalog of bacterial flagellar diversity

    The Diguanylate Cyclase SadC Is a Central Player in Gac/Rsm-Mediated Biofilm Formation in Pseudomonas aeruginosa

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    Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen and a threat for immune-compromised and Cystic Fibrosis patients. It is responsible for acute and chronic infections and can switch between these lifestyles upon taking an informed decision involving complex regulatory networks. The RetS/LadS/Gac/Rsm network and the c-di-GMP signaling pathways are both central to this phenomenon redirecting the P. aeruginosa population towards a biofilm mode of growth, which is associated with chronic infections. While these two pathways were traditionally studied independently from each other, we recently showed that cellular levels of c-di-GMP are increased in the hyperbiofilm retS mutant. Here, we have formally established the link between the two networks by showing that the SadC diguanylate cyclase is central to the Gac/Rsm-associated phenotypes, notably biofilm formation. Importantly, SadC is involved in the signaling that converges onto the RsmA translational repressor either via RetS/LadS or via HptB/HsbR. Although the level of expression of the sadC gene does not seem impacted by the regulatory cascade, the production of the SadC protein is tightly repressed by RsmA. This adds to the growing complexity of the signaling network associated with c-di-GMP in P. aeruginosa. While this organism possesses more than forty c-di-GMP-related enzymes it remains unclear how signaling specificity is maintained within the c-di-GMP network. The finding that SadC but no other diguanylate cyclase is related to the formation of biofilm governed by the Gac/Rsm pathway further contributes to understand this insulation mechanism

    Allosteric control of cyclic di-GMP signaling

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    Cyclic di-guanosine monophosphate is a bacterial second messenger that has been implicated in biofilm formation, antibiotic resistance, and persistence of pathogenic bacteria in their animal host. Although the enzymes responsible for the regulation of cellular levels of c-di-GMP, diguanylate cyclases (DGC) and phosphodiesterases, have been identified recently, little information is available on the molecular mechanisms involved in controlling the activity of these key enzymes or on the specific interactions of c-di-GMP with effector proteins. By using a combination of genetic, biochemical, and modeling techniques we demonstrate that an allosteric binding site for c-di-GMP (I-site) is responsible for non-competitive product inhibition of DGCs. The I-site was mapped in both multi- and single domain DGC proteins and is fully contained within the GGDEF domain itself. In vivo selection experiments and kinetic analysis of the evolved I-site mutants led to the definition of an RXXD motif as the core c-di-GMP binding site. Based on these results and based on the observation that the I-site is conserved in a majority of known and potential DGC proteins, we propose that product inhibition of DGCs is of fundamental importance for c-di-GMP signaling and cellular homeostasis. The definition of the I-site binding pocket provides an entry point into unraveling the molecular mechanisms of ligand-protein interactions involved in c-di-GMP signaling and makes DGCs a valuable target for drug design to develop new strategies against biofilm-related diseases

    Desain Pisau Pengurai dan Sistem Pengayak serta Uji Produk Mesin Pengolah Sabut Kelapa sebagai Bahan Mentah Komposit

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    This research aims to design a decomposing blade, sieving system, and test machine products. The method for completing coconut fiber processing machines consists of three stages, namely the design and production process stages, as well as machine product testing. This research produces the following data, namely the design of the untangling knife which is a combination of the functions of the coir untangling knife for random and woven results. Calculation of the equilibrium moment on the shaft obtained a value of is 28.68 N and the reaction at point A was is 28.32 N, with the diameter of the shaft used in the coconut fiber sieving machine transmission system being Ø28 mm. Fiber uniformity is obtained from twice decomposition processes, whereas the level of fiber/powder uniformity is influenced by the long sieving process time and also the high rotational speed of the sieve

    PENGGUNAAN TANAH BENTONIT SEBAGAI ADSORBEN LOGAM Cu

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    Bentonite serve the purpose of substance adsorpsi because swelling ability and cation for exchange. But adsorption ability is limited so that require to be activated by strong acid to higher level adsorption of bentonite. This research use Ca-Bentonit activated by strong acid HCl. Cation Cu analysed by using Spektofometri Serapan Atom (SSA).  Result of research  indicate that the increasing of HCl concentration and activation time can improve the adsorption capacity of bentonite. Maximum HCl concentration at 1,6 M and maximum activation time at 24 hour. Optimum heavy bentonite at 4 gr of 100 ppm Cu solution and optimum contact time at 2 hour. Result from Cu isoterm adsorption is weight of adsorption have same range with Cu concentratio

    BolA Is Required for the Accurate Regulation of c-di-GMP, a Central Player in Biofilm Formation

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    The bacterial second messenger cyclic dimeric GMP (c-di-GMP) is a nearly ubiquitous intracellular signaling molecule involved in the transition from the motile to the sessile/biofilm state in bacteria. C-di-GMP regulates various cellular processes, including biofilm formation, motility, and virulence. BolA is a transcription factor that promotes survival in different stresses and is also involved in biofilm formation. Both BolA and c-di-GMP participate in the regulation of motility mechanisms leading to similar phenotypes. Here, we establish the importance of the balance between these two factors for accurate regulation of the transition between the planktonic and sessile lifestyles. This balance is achieved by negative-feedback regulation of BolA and c-di-GMP. BolA not only contributes directly to the motility of bacteria but also regulates the expression of diguanylate cyclases and phosphodiesterases. This expression modulation influences the synthesis and degradation of c-di-GMP, while this signaling metabolite has a negative influence in bolA mRNA transcription. Finally, we present evidence of the dominant role of BolA in biofilm, showing that, even in the presence of elevated c-di-GMP levels, biofilm formation is reduced in the absence of BolA. C-di-GMP is one of the most important bacterial second messengers involved in several cellular processes, including virulence, cell cycle regulation, biofilm formation, and flagellar synthesis. In this study, we unravelled a direct connection between the bolA morphogene and the c-di-GMP signaling molecule. We show the important cross-talk that occurs between these two molecular regulators during the transition between the motile/planktonic and adhesive/sessile lifestyles in Escherichia coli This work provides important clues that can be helpful in the development of new strategies, and the results can be applied to other organisms with relevance for human health.IMPORTANCE Bacterial cells have evolved several mechanisms to cope with environmental stresses. BolA-like proteins are widely conserved from prokaryotes to eukaryotes, and in Escherichia coli, in addition to its pleiotropic effects, this protein plays a determinant role in bacterial motility and biofilm formation regulation. Similarly, the bacterial second messenger c-di-GMP is a molecule with high importance in coordinating the switch between planktonic and sessile life in bacteria. Here we have unravelled the importance of accurate regulation of cross-talk between BolA and c-di-GMP for a proper response in the regulation of these bacterial lifestyles. This finding underlines the complexity of bacterial cell regulation, revealing the existence of one additional tool for fine-tuning such important cellular molecular mechanisms. The relationship between BolA and c-di-GMP gives new perspectives regarding biofilm formation and opens the possibility to extend our studies to other organisms with relevance for human health

    ASSESSMENT OF THE ACOUSTICAL PERFORMANCE IN MALACCA MOSQUE,MALAYSIA: A CASE STUDY ON THE SAYYIDINA ABU BAKAR MOSQUE

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    As a building for worship and one of the important symbols in Islam, a mosque is usually designed with its architectural grandeur. Among of the characteristics is its spacious interior to create a perception so that people will feel ’small’ when entering the house of God. Most mosques therefore have high ceiling and are usually constructed with dome shape. In Malacca, Malaysia however, the architectural of the mosque resembles the traditional Malay house where the ceiling follows a pyramidal shape. This paper discusses the acoustical condition of the mosque in Malacca. The Sayyidina Abu Bakar Mosque is presented here for a case study. Measurement of its reverberation time was conducted and the results are validated with simulation data from CATT room acoustics software. Other important acoustical parameters are evaluated such as the early decay time, clarity, definition, lateral fraction and speech transmission index

    Precise Timing of Transcription by c-di-GMP Coordinates Cell Cycle and Morphogenesis in Caulobacter

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    Bacteria adapt their growth rate to their metabolic status and environmental conditions by modulating the length of their G1 period. Here we demonstrate that a gradual increase in the concentration of the second messenger c-di-GMP determines precise gene expression during G1/S transition in Caulobacter crescentus . We show that c-di-GMP stimulates the kinase ShkA by binding to its central pseudo-receiver domain, activates the TacA transcription factor, and initiates a G1/S-specific transcription program leading to cell morphogenesis and S-phase entry. Activation of the ShkA-dependent genetic program causes c-di-GMP to reach peak levels, which triggers S-phase entry and promotes proteolysis of ShkA and TacA. Thus, a gradual increase of c-di-GMP results in precise control of ShkA-TacA activity, enabling G1/S-specific gene expression that coordinates cell cycle and morphogenesis
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