14,235 research outputs found
LC-MS/MS data for Zhang et al. NCB paper
No full textData deposited here include different type of RNA modifications examined by LC-MS/MS (liquid chromatography–tandem mass spectrometry). Different types of RNA modifications in sperm RNA fractions (15-25nt, 30-40nt, 40-100nt and >100 nt) extracted from F0 Dnmt2+/+ and Dnmt2-/- male mice under ND (normal diet) and HFD (High-fat diet) are processed for LC-MS/MS analysis
LC compensators for power factor correction of nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEA method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples
LC compensators based on transmission loss minimization for nonlinear loads
No full textThis material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThis paper presents a method employing the penalty function search algorithm to determine the LC compensator value for the optimal power factor correction in nonsinusoidal systems. The objective of the proposed method is to minimize the transmission loss while the power factor and efficiency are taken as constraints and utilized in order to solve the multiobjective optimization problem by transforming it into a single objective one. Examples show that the load nonlinearity can have a significant impact on optimal compensator sizes
A - 121.5-dB THD Class-D Audio Amplifier With 49-dB LC Filter Nonlinearity Suppression
No full textClass-D audio amplifiers produce electromagnetic interference (EMI), which often needs to be suppressed by an external LC filter. However, due to component nonlinearity, this filter can itself cause significant distortion. This article presents a class-D amplifier that suppresses LC filter nonlinearity by 49 dB and is robust to ±30% variations in its cutoff frequency. This is achieved by a dual-loop architecture, in which an inner loop provides stability, while an outer loop provides the high gain needed to suppress the LC filter and output-stage nonlinearity. A prototype, implemented in a 180-nm BCD process, achieves -121.5-dB total harmonic distortion (THD) and -107.1-dB THD+N, which is maintained to within 3 dB even as the LC filter cutoff frequency is varied from 62 to 106 kHz. It can deliver a maximum of 21 W into a 4-Ω load with 87% efficiency and 12 W into an 8-Ω load with 91% efficiency, measured at 10% THD. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
LC-MS-P/N-ALL.xml
No full textMetabolic data of Artemisia argyi and Artemisia indica at different periods (LC-MS) .</p
A 155W −95.6 dB THD+N GaN-based Class-D Audio Amplifier With LC Filter Nonlinearity Compensation
No full textSilicon MOSFETs-based medium-power (< 50W) Class-D amplifiers (CDAs) switching in the MHz range have gained popularity in recent years, which achieves better linearity thanks to a higher loop gain in the audio band while enabling the use of LC filters with higher cut-off frequencies. However, for high-power (>100 W) CDAs, such switching frequency and high load current could lead to significant power loss. Furthermore, in the presence of a large current and voltage applied to the load, the linearity of the system can quickly degrade due to LC filter component voltage/current dependency. Without any LC filter nonlinearity compensation technique, LC components with high voltage/current rating must be used to reach high system linearity, which are often expensive and bulky. This paper presents a CDA using a GaN-based output stage to achieve high switching frequency and good efficiency simultaneously, and an integrated controller implemented in a 180nm CMOS technology to compensate for the LC filter nonlinearity. Switching at 1.8 MHz, the CDA can deliver a maximum of 155W from a 50V supply into a load with a peak efficiency of 91.7%. It achieves a peak THD+N of −95.6 dB (0.0017%) while allowing the use of cheaper and smaller nonlinear LC components.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and MaterialsMicroelectronic
THE PLASTIC WRINKLING OF AN ANNULAR PLATE UNDER UNIFORM TENSION ON ITS INNER EDGE
No full textThis paper analyses the plastic wrinkling of an annular plate subjected to in-plane uniform tension stress on its inner edge with the combined use of the Kantorovich method and the Galerkin method, and discusses the appearance of wrinkles on the flange of a metal circular sheet during its axisymmetric deep-drawing operation. It is shown that the method provided in this paper is simple, convenient, and very suitable for engineering applications.MechanicsSCI(E)EI6ARTICLE5497-5032
AN INVESTIGATION OF THE BRAZIER EFFECT OF A CYLINDRICAL TUBE UNDER PURE ELASTIC PLASTIC BENDING
No full textEngineering, MultidisciplinaryEngineering, MechanicalSCI(E)18ARTICLE277-863
Apex Peptide Elution Chain Selection: A New Strategy for Selecting Precursors in 2D-LC-MALDI-TOF/TOF Experiments on Complex Biological Samples
No full textLC-MALDI provides an often overlooked opportunity to exploit the separation between LC-MS and MS/MS stages of a 2D-LC-MS-based proteomics experiment, that is, by making a smarter selection for precursor fragmentation. Apex Peptide Elution Chain Selection (APECS) is a simple and powerful method for intensity-based peptide selection in a complex sample separated by 2D-LC, using a MALDI-TOF/TOF instrument. It removes the peptide redundancy present in the adjacent first-dimension (typically strong cation exchange, SCX) fractions by constructing peptide elution profiles that link the precursor ions of the same peptide across SCX fractions. Subsequently, the precursor ion most likely to fragment successfully in a given profile is selected for fragmentation analysis, selecting on precursor intensity and absence of adjacent ions that may cofragment. To make the method independent of experiment-specific tolerance criteria, we introduce the concept of the branching factor, which measures the likelihood of false clustering of precursor ions based on past experiments. By validation with a complex proteome sample of Arabidopsis thaliana, APECS identified an equivalent number of peptides as a conventional data-dependent acquisition method but with a 35% smaller work load. Consequently, reduced sample depletion allowed further selection of lower signal-to-noise ratio precursor ions, leading to a larger number of identified unique peptides.
LC/MS peptide alignment and identification approach based on replicate spectral data
No full textThis item is available only to currently enrolled UTSA students, faculty or staff. To download, navigate to Log In in the top right-hand corner of this screen, then select Log in with my UTSA ID.Liquid Chromatography/Mass Spectrometry (LC-MS) is becoming a widely-used approach for quantifying the protein composition of complex samples. The LC-MS spectra show the intensity of a peptide feature with a specific mass-charge ratio (m/z) and retention time. This technology has been used to compare complex biological samples from multiple LC-MS experiments. One challenge for comparison is to match corresponding peptide features from different LC-MS experiments. Alignment corrects for experimental variations in the chromatography, which is an important technology for the comparison of LC-MS experiments.
The corresponding feature pair is two features that are generated exactly by the same peptide in replicates. There are two key steps for corresponding feature identification: alignment and identification. Alignment gives the corresponding and non-corresponding feature pairs together and the identification step can choose the corresponding feature out of the total pairs.
Before the alignment and identification steps, it is needed to perform LC peak detection accurately. Instead of checking MS templates at the base position, the author checks the consistency of isotope patterns on the premises that peptides produce consistent isotope patterns on scans within their elution periods. After accurate elution peak detection, the author obtains the candidate elution profiles for the peptides. The author verifies the interval detection method on SILAC data. The dissertation compared several quantification method based on the accurate interval detection. The performance of H/L ratio is much better than the result from Maxquant.
Common alignment methods use warping functions to correct elution time shifts between two different LC-MS datasets to identify corresponding features (LC peaks registered by the same peptide). Although a warping function can correct the mean difference of elution time shifts, it alone cannot resolve the ambiguity in alignment completely because elution time shifts are random. Instead the author explored the R-statistic to measure the similarity in LC peak shapes between corresponding feature pairs for alignment, which means the correlation between two elution profiles.
In Super-SILAC labeled data, based on MS/MS identifications, considered that the LC peak shape is an important factor for alignment, the author proposed a Statistical Corresponding Feature Identification Algorithm (SCFIA) based on both time shifts and the similarity of LC peak shapes between corresponding features. The author tested SCFIA on publicly available datasets and compared its performance with that of warping function based methods. The accuracy and the number of detected corresponding features are improved significantly.
In 18O labeled data, as the author mentioned above, warping functions are commonly used to correct elution time shifts, which cannot resolve the ambiguity completely because elution time shifts are unpredicted. So the author takes peak shape, labeling efficiency, peptide isotope pattern and peptide predicted elution time into consideration.
The author compared the algorithm, which is not only based on elution time shift but also many other parameters, to the other software. The result shows a great improvement.Electrical and Computer Engineerin
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