464 research outputs found
Analysis of crosstalk and field coupling to lossy MTL's in a SPICE environment
This paper proposes a circuit model for lossy multiconductor transmission lines (MTLs) suitable for implementation in modern SPICE simulators, as well as in any simulator supporting differential operators. The model includes the effects of a uniform or nonuniform disturbing field illuminating the line and is especially devised for the transient simulation of electrically long wideband interconnects with frequency dependent per-unit-length parameters. The MTL is characterized by its transient matched scattering responses, which are computed including both dc and skin losses by means of a specific algorithm for the inversion of the Laplace transform. The line characteristics are then represented in terms of differential operators and ideal delays to improve the numerical efficiency and to simplify the coding of the model in existing simulators. The model can be successfully applied to many kinds of interconnects ranging from micrometric high-resistivity metallizations to low-loss PCBs and cables, and can be considered a practical extension of the widely appreciated lossless MTL SPICE model, which maintains the simplicity and efficienc
Bioinorganic Chemistry
This book covers material that could be included in a one-quarter or one-semester course in bioinorganic chemistry for graduate students and advanced undergraduate students in chemistry or biochemistry. We believe that such a course should provide students with the background required to follow the research literature in the field. The topics were chosen to represent those areas of bioinorganic chemistry that are mature enough for textbook presentation. Although each chapter presents material at a more advanced level than that of bioinorganic textbooks published previously, the chapters are not specialized review articles. What we have attempted to do in each chapter is to teach the underlying principles of bioinorganic chemistry as well as outlining the state of knowledge in selected areas.
We have chosen not to include abbreviated summaries of the inorganic chemistry, biochemistry, and spectroscopy that students may need as background in order to master the material presented. We instead assume that the instructor using this book will assign reading from relevant sources that is appropriate to the background of the students taking the course.
For the convenience of the instructors, students, and other readers of this book, we have included an appendix that lists references to reviews of the research literature that we have found to be particularly useful in our courses on bioinorganic chemistry
Sodium Doped LaMnO3 Thin Films: Influence of Substrate and Thickness on Physical Properties
In this paper we report the results about the synthesis and characterization
of optimally doped La1-xNaxMnO3 thin films grown onto SrTiO3 (100), NdGaO3
(100) and NdGaO3 (110) for thickness ranging from 11 to 82 nm. The effect of
substrate nature and orientation, film thickness and annealing procedure was
investigated in order to optimize their magnetoresistance (MR). We obtained
very smooth films displaying MR values greater than 70%, near to room
temperature.Comment: 31 pages, 9 figures Final version to appear in J. Phys. Chem.
Audit Keamanan Informasi: Studi Kasus PT Xyz
PT XYZ is a provider of document management services, in cooperation with local/foreign banks. Documents containing customer information, so that information security should be set to provide services that meet information security criteria. Information security audit results showed weak information security, less monitored and evaluated. This research focuses on information security audit in accordance with ISO 27001 to provide comprehensive information security policies and procedures. The methodology used are assessment, risk analysis and impact, controls selection and recommendation of policies and procedures. Audit results showed a gap between policies and procedures that apply in PT XYZ with ISO 27001
Three-Dimensional Solution Structure of Saccharomyces cerevisiae Reduced Iso-l-cytochromec
Two-dimensional ^1H NMR spectra of Saccharomyces cerevisiae reduced iso-1-cytochrome c have been used to confirm and slightly extend the assignment available in the literature. 1702 NOESY cross-peaks have been assigned, and their intensities have been measured. Through the program DIANA and related protocols (Güntert, 1992), a solution structure has been obtained by using 1442 meaningful NOEs and 13 hydrogen-bond constraints. The RMSD values with respect to the mean structure for the backbone and all heavy atoms for a family of 20 structures are 0.61 ± 0.09 and 0.98 ± 0.09 Å, the average target function value being as small as 0.57 Å^2. The larger number of slowly exchanging amide NHs observed in this system compared to that observed in the cyanide derivative of oxidized Ala 80 cytochrome c suggests that the oxidized form is much more flexible and that the backbone protons are more solvent accessible. Comparison of the present structure with the crystal structures of reduced yeast cytochrome c and of the complex between cytochrome c peroxidase and oxidized yeast cytochrome c reveals substantial similarity among the backbone conformations but differences in the residues located in the region of protein−protein interaction. Interestingly, in solution the peripheral residues involved in the interaction with cytochrome c peroxidase are on average closer to the position found in the crystal structure of the complex than to the solid state structure of the isolated reduced form
Solution Structure of Oxidized Horse Heart Cytochrome c
The solution structure of oxidized horse heart cytochrome c was obtained at pH 7.0 in 100 mM phosphate buffer from 2278 NOEs and 241 pseudocontact shift constraints. The final structure was refined through restrained energy minimization. A 35-member family, with RMSD values with respect to the average structure of 0.70 ± 0.11 Å and 1.21 ± 0.14 Å for the backbone and all heavy atoms, respectively, and with an average penalty function of 130 ± 4.0 kJ/mol and 84 ± 3.7 kJ/mol for NOE and pseudocontact shift constraints, respectively (corresponding to a target function of 0.9 Å^2 and 0.2 Å^2), was obtained. The solution structure is somewhat different from that recently reported (Qi et al., 1996) and appears to be similar to the X-ray structure of the same oxidation state (Bushnell et al., 1990). A noticeable difference is a rotation of 17 ± 8° of the imidazole plane between solid and solution structure. Detailed and accurate structural determinations are important within the frame of the current debate of the structural rearrangements occurring upon oxidation or reduction. From the obtained magnetic susceptibility tensor a separation of the hyperfine shifts into their contact and pseudocontact contributions is derived and compared to that of the analogous isoenzyme from S. cerevisiae and to previous results
Structural Model for an Alkaline Form of Ferricytochrome c
An ^(15)N-enriched sample of the yeast iso-1-ferricytochrome c triple variant (Lys72Ala/Lys79Ala/Cys102Thr) in an alkaline conformation was examined by NMR spectroscopy. The mutations were planned to produce a cytochrome c with a single conformer. Despite suboptimal conditions for the collection of spectra (i.e., pH ≈ 11), NMR remains a suitable investigation technique capable of taking advantage of paramagnetism. 76% of amino acids and 49% of protons were assigned successfully. The assignment was in part achieved through standard methods, in part through the identification of groups maintaining the same conformation as in the native protein at pH 7 and, for a few other residues, through a tentative analysis of internuclear distance predictions. Lys73 was assigned as the axial ligand together with His18. In this manner, 838 meaningful NOEs for 108 amino acids, 50 backbone angle constraints, and 203 pseudocontact shifts permitted the convergence of randomly generated structures to a family of conformers with a backbone RMSD of 1.5 ± 0.2 Å. Most of the native cytochrome c conformation is maintained at high pH. The NOE pattern that involves His18 clearly indicates that the proximal side of the protein, including the 20s and 40s loops, remains essentially intact. Structural differences are concentrated in the 70−80 loop, because of the replacement of Met80 by Lys73 as an axial ligand, and in the 50s helix facing that loop; as a consequence, there is increased exposure of the heme group to solvent. Based on several spectral features, we conclude that the folded polypeptide is highly fluxional
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A High Space Density of Luminous Lyα Emitters at z ~ 6.5
We present the results of a systematic search for Lyα emitters (LAEs) at 6 ≾ z ≾ 7.6 using the HST WFC3 Infrared Spectroscopic Parallel (WISP) Survey. Our total volume over this redshift range is ~ 8 x 10^5 Mpc^3, comparable to many of the narrowband surveys despite their larger area coverage. We find two LAEs at z = 6.38 and 6.44 with line luminosities of L_(Lyα) ~ 4.7 x 10^(43) erg s^(−1), putting them among the brightest LAEs discovered at these redshifts. Taking advantage of the broad spectral coverage of WISP, we are able to rule out almost all lower-redshift contaminants. The WISP LAEs have a high number density of 7.7 x 10(-6) Mpc^(−3). We argue that the LAEs reside in megaparsec-scale ionized bubbles that allow the Lyα photons to redshift out of resonance before encountering the neutral intergalactic medium. We discuss possible ionizing sources and conclude that the observed LAEs alone are not sufficient to ionize the bubbles
Exploiting tumour addiction with a serine and glycine-free diet.
Understanding cancer metabolism is key to unveil the Achilles’ heel of cancer cells and provide novel therapeutic interventions for patients. While the rerouting of metabolic pathways during development1 or cancer transformation and progression2, 3, 4 has been extensively characterised, the exact dynamic of these events, their distribution and frequency in the different tumour types, and the correlation with genetic background remain largely unknown. In a recent article published in Nature, Karen Vousden’s team assesses the effect of serine and glycine dietary restriction in autochthonous mouse tumour models driven by different oncogenes (Maddocks et al, 2017)5, leading to potential area of therapeutic intervention
Flux Modulations seen by the Muon Veto of the GERDA Experiment
The GERDA experiment at LNGS of INFN is equipped with an active muon veto.
The main part of the system is a water Cherenkov veto with 66~PMTs in the water
tank surrounding the GERDA cryostat. The muon flux recorded by this veto shows
a seasonal modulation. Two effects have been identified which are caused by
secondary muons from the CNGS neutrino beam (2.2 %) and a temperature
modulation of the atmosphere (1.4 %). A mean cosmic muon rate of /(sm) was found in good agreement with other experiments at
LNGS at a depth of 3500~meter water equivalent.Comment: 7 pages, 6 figure
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