Biodesulfurization of dibenzothiophene by Shewanella putrefaciens NCIMB 8768

The desulfurization ability of Shewanella putrefaciens strain NCIMB 8768 was studied and its activity profile was compared with the widely studied strain Rhodococcus erythropolis strain IGTS8. Dibenzothiophene (DBT) is a recalcitrant thiophenic component of fossil fuels especially among diesel blend stocks. DBT in basic salt medium (BSM) at a final concentration of 0.3, 0.6 and 0.9 mM was supplied to the microbes as the sole sulfur source. Experimental results showed that S. putrefaciens, similar to other biodesulfurization organisms, converted DBT to the end product 2-hydroxybiphenyl (HBP), as detected by the Gibbs assay and HPLC. Cells cultivated in medium containing 0.3 mM of DBT showed the highest desulfurization activity, with a maximum specific production rate 43.5 mmol/L of HBP

Temperature-sensitive protein–DNA dimerizers

Programmable DNA-binding polyamides coupled to short peptides have led to the creation of synthetic artificial transcription factors. A hairpin polyamide-YPWM tetrapeptide conjugate facilitates the binding of a natural transcription factor Exd to an adjacent DNA site. Such small molecules function as protein-DNA dimerizers that stabilize complexes at composite DNA binding sites. Here we investigate the role of the linker that connects the polyamide to the peptide. We find that a substantial degree of variability in the linker length is tolerated at lower temperatures. At physiological temperatures, the longest linker tested confers a "switch"-like property on the protein-DNA dimerizer, in that it abolishes the ability of the YPWM moiety to recruit the natural transcription factor to DNA. These observations provide design principles for future artificial transcription factors that can be externally regulated and can function in concert with the cellular regulatory circuitry

Signal recovery from wavelet transform maxima

Cataloged from PDF version of article.This paper presents an iterative algorithm for signal recovery from discrete-time wavelet transform maxima. The signal recovery algorithm is developed by using the method of projections onto convex sets. Convergence of the algorithm is assured

Sistem Pakar Kerusakan Motor Kendaraan Roda Dua Jenis Yamaha Matic pada Reza Jaya Motor Samarinda

Tulisan ini memuat bagaimana melakukan diagnosa kerusakan pada motor Yamaha matic dengan menggunakan metode Forward Chaining dan Certainty Factor Sebagai tolak ukur tingkat kepercayaan dari sistem. Forward Chaining sebuah metode Pencocokan fakta atau pernyataan dimulai dari bagian sebelah kiri. Dengan kata lain, penalaran dimulai dari fakta terlebih dahulu, lalu dicari rule yang sesuai dengan fakta – fakta dengan menginputkan dari macam kerusakan, ke fakta Gejala yang dirasakan pengguna untuk menguji kebenaran hipotesa sehinggga menghasilkan sebuah atau beberapa solusi. Metode pengembangan sistem yang digunakan pada tulisan ini menggunakan waterfall. Adapun langkah – langkah dari waterfall itu sendiri yaitu: Kebutuhan Sistem, Spesifikasi Kebutuhan Sistem perangkat lunak, Design perangkat lunak, Implementasi perangkat lunak, Uji mesin formal, operasi dan perawatan sistem. Metode pe ngujian yang di gunakan di dalam tulisan ini menggunakan white box dan Black box. Aplikasi yang dikembangkan digunakan untuk mengetahui gejala-gejala kerusakan dan mencari solusi yang tepat terhadap kerusakan yang dialami terhadap kendaraan roda dua jenis Yamaha merk mio soul pada Reza Jaya Motor Samarinda, agar teknisi dapat mengetahui segaja jenis kerusakan terdapat kendaraan yang masuk untuk diservice atau diperbaiki

Analysis of Residue Probability Density Function and Comparator Offset Error in Pipelined ADCs

This paper presents a new approach to analyze the convergence of residue probability density function (pdf) in pipelined ADCs. Compared to the previous approaches, in the proposed approach, in addition to the analysis of residue pdfs for different input densities, the analysis of the sub-ADC comparator offsets impact on output pdf is possible. Using Fourier analysis, it will be shown that the residue density converges to uniformity. In the half-bit redundant structure, residue pdf concentrates in the center half of the stage full-scale range and 6 dB of extra resolution can be gained. Also, the share of each stage in this resolution improvement is investigated. Examining the sub-ADC threshold offsets impact on residue pdfs, it is observed that with respect to the impact on converter additional resolution, the final stages offset errors are more significant than the first stages offsets

DBT degradation enhancement by decorating Rhodococcus erythropolis IGST8 with magnetic Fe3O4 nanoparticles

Biodesulfurization (BDS) of dibenzothiophene (DBT) was carried out by Rhodococcus erythropolis IGST8 decorated with magnetic Fe3O4 nanoparticles, synthesized in-house by a chemical method, with an average size of 45-50 nm, in order to facilitate the post-reaction separation of the bacteria from the reaction mixture. Scanning electron microscopy (SEM) showed that the magnetic nanoparticles substantially coated the surfaces of the bacteria. It was found that the decorated cells had a 56% higher DBT desulfurization activity in basic salt medium (BSM) compared to the nondecorated cells. We propose that this is due to permeabilization of the bacterial membrane, facilitating the entry and exit of reactant and product, respectively. Model experiments with black lipid membranes (BLM) demonstrated that the nanoparticles indeed enhance membrane permeability

Pengaruh Penggunaan Model Pembelajaran Berbasis Masalah Terhadap Kemampuan Menulis Teks Diskusi Oleh Siswa Kelas VIII SMP Negeri 2 Berastagi Tahun Pembelajaran 2014/2015

Penelitian ini untuk mengetahui pengaruh penggunaan model pembelajaran berbasis masalah terhadap kemampuan menulis teks diskusi oleh siswa kelas VIII SMP Negeri 2 Berastagi tahun pembelajaran 2014/2015. Populasi penelitian ini adalah seluruh siswa kelas VIII SMP Negeri 2 Berastagi yang berjumlah 300 orang. Sampel penelitian ini adalah siswa kelas VIII-7 yang berjumlah 30 orang. Dalam menentukan jumlah sampel dilakukan dengan teknik random sampling atau acak kelas. Metode penelitian ini adalah metode eksperimen dengan desain one group pre-test post-test design. Instrumen yang digunakan adalah tes menulis teks diskusi dalam bentuk penugasan. Nilai rata-rata pre-test adalah 61,83, sedangkan nilai rata-rata post-test adalah 78,33. Dengan demikian dapat disimpulkan bahwa nilai rata-rata post-test lebih tinggi daripada nilai pre-test. Pengujian hipotesis dilakukan dengan menggunakan uji “t”. Dari perhitungan uji hipotesis diperoleh thitung = 4,77 selanjutnya dikonsultasikan dengan tabel pada taraf signifikansi 5% dengan df = n-1 = 30-1 = 29. Dari df = 29 diperoleh taraf signifikansi sebesar 2,04. Berdasarkan perhitungan yang telah dilakukan, maka dapat diketahui bahwa thitung > ttabel , yakni 4,77 > 2,04. Dengan demikian, hipotesis alternatif (Ha) diterima. Maka, dapat disimpulkan bahwa model pembelajaran berbasis masalah berpengaruh terhadap kemampuan menulis teks diskusi siswa kelas VIII SMP Negeri 2 Berastagi Tahun Pembelajaran 2014/2015

Large Magellanic Cloud Microlensing Optical Depth with Imperfect Event Selection

I present a new analysis of the MACHO Project 5.7 year Large Magellanic Cloud (LMC) microlensing data set that incorporates the effects of contamination of the microlensing event sample by variable stars. Photometric monitoring of MACHO LMC microlensing event candidates by the EROS and OGLE groups has revealed that one of these events is likely to be a variable star, while additional data has confirmed that many of the other events are very likely to be microlensing. This additional data on the nature of the MACHO microlensing candidates is incorporated into a simple likelihood analysis to derive a probability distribution for the number of MACHO microlens candidates that are true microlensing events. This analysis shows that 10-12 of the 13 events that passed the MACHO selection criteria are likely to be microlensing events, with the other 1-3 being variable stars. This likelihood analysis is also used to show that the main conclusions of the MACHO LMC analysis are unchanged by the variable star contamination. The microlensing optical depth toward the LMC is = 1.0 +/- 0.3 * 10^{-7}. If this is due to microlensing by known stellar populations, plus an additional population of lens objects in the Galactic halo, then the new halo population would account for 16% of the mass of a standard Galactic halo. The MACHO detection exceeds the expected background of 2 events expected from ordinary stars in standard models of the Milky Way and LMC at the 99.98% confidence level. The background prediction is increased to 3 events if maximal disk models are assumed for both the MilkyWay and LMC, but this model fails to account for the full signal seen by MACHO at the 99.8% confidence level.Comment: 20 pages, 2 postscript figues, accepted by Ap