Developing a voltage-stability-constrained security assessment system part I: Determination of power system voltage security operation limits

The method for determining the voltage security operation limits in a practical voltage security analysis (VSA) system based on VSAT software for large power systems is introduced in this paper. These operation limits include bus voltage limits, branch/corridor transfer power limits and P-load limit of the whole system. The voltage security operation limits are determined by the most critical contingency among the studied contingency set. The most critical contingency determines the P-load limit of the whole system, and all kinds of operation parameter limits are operation parameter values corresponding to this P-load limit under pre-contingency. An operation parameter limit is upper limit if the function relationship between this operation parameter and load power is an increasing curve, or lower limit if the function relationship between this operation parameter and load power is an decreasing curve. These operation parameter limits are helpful for operators to monitor the system operation state. © 2005 IEEE.published_or_final_versio

Developing a voltage-stability-constrained security assessment system part II : Structure and function design and technology used

This is the second part in a two-part paper on the development of a voltage stability constrained security assessment system (VSC-SAS). In this part, overall VSC-SAS structure and function design and technology used will be presented. The system is expected to be used in both on-line and off-line modes. In on-line mode, on-line SCADA/EMS data will be used for VSC-SAS use; while in off-line mode (usually day-ahead calculation), historical data can be used for VSC-SAS. Both results (i.e. system operation limits) can be selected to compare with real time operation conditions and supervision power system operation security margin. © 2005 IEEE.published_or_final_versio

Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging

Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence.1152sciescopu

Enhanced Axial Resolution of Wide-Field Two-Photon Excitation Microscopy by Line Scanning Using a Digital Micromirror Device

Temporal focusing multiphoton microscopy is a technique for performing highly parallelized multiphoton microscopy while still maintaining depth discrimination. While the conventional wide-field configuration for temporal focusing suffers from sub-optimal axial resolution, line scanning temporal focusing, implemented here using a digital micromirror device (DMD), can provide substantial improvement. The DMD-based line scanning temporal focusing technique dynamically trades off the degree of parallelization, and hence imaging speed, for axial resolution, allowing performance parameters to be adapted to the experimental requirements. We demonstrate this new instrument in calibration specimens and in biological specimens, including a mouse kidney slice.We acknowledge support from the National Institute of Health 5-P41-EB015871-28, 2R01EY017656-06, R21-NS091982-01, 1-U01-NS090438-01, 1U01CA202177-01, and 1R01HL121386-01A1, Singapore-MIT Alliance for Science and Technology, Connecticut Children’s Medical Center, Hamamatsu Corp., and Samsung Advanced Institute of Technology. C.J.R. further acknowledges support from the Wellcome Trust 093831/Z/10/Z

Exome-wide somatic mutation characterization of small bowel adenocarcinoma

Small bowel adenocarcinoma (SBA) is an aggressive disease with limited treatment options. Despite previous studies, its molecular genetic background has remained somewhat elusive. To comprehensively characterize the mutational landscape of this tumor type, and to identify possible targets of treatment, we conducted the first large exome sequencing study on a population-based set of SBA samples from all three small bowel segments. Archival tissue from 106 primary tumors with appropriate clinical information were available for exome sequencing from a patient series consisting of a majority of confirmed SBA cases diagnosed in Finland between the years 2003-2011. Paired-end exome sequencing was performed using Illumina HiSeq 4000, and OncodriveFML was used to identify driver genes from the exome data. We also defined frequently affected cancer signalling pathways and performed the first extensive allelic imbalance (Al) analysis in SBA. Exome data analysis revealed significantly mutated genes previously linked to SBA (TP53, KRAS, APC, SMAD4, and BRAF), recently reported potential driver genes (SOX9, ATM, and ARID2), as well as novel candidate driver genes, such as ACVR2A, ACVR1B, BRCA2, and SMARCA4. We also identified clear mutation hotspot patterns in ERBB2 and BRAF. No BRAF V600E mutations were observed. Additionally, we present a comprehensive mutation signature analysis of SBA, highlighting established signatures 1A, 6, and 17, as well as U2 which is a previously unvalidated signature. Finally, comparison of the three small bowel segments revealed differences in tumor characteristics. This comprehensive work unveils the mutational landscape and most frequently affected genes and pathways in SBA, providing potential therapeutic targets, and novel and more thorough insights into the genetic background of this tumor type.Peer reviewe

Domestication syndrome is investigated by proteomic analysis between cultivated cassava (Manihot esculenta Crantz) and its wild relatives

Cassava (Manihot esculenta Crantz) wild relatives remain a largely untapped potential for genetic improvement. However, the domestication syndrome phenomena from wild species to cultivated cassava remain poorly understood. The analysis of leaf anatomy and photosynthetic activity showed significantly different between cassava cultivars SC205, SC8 and wild relative M. esculenta ssp. Flabellifolia (W14). The dry matter, starch and amylose contents in the storage roots of cassava cultivars were significantly more than that in wild species. In order to further reveal the differences in photosynthesis and starch accumulation of cultivars and wild species, the globally differential proteins between cassava SC205, SC8 and W14 were analyzed using 2-DE in combination with MALDI-TOF tandem mass spectrometry. A total of 175 and 304 proteins in leaves and storage roots were identified, respectively. Of these, 122 and 127 common proteins in leaves and storage roots were detected in SC205, SC8 and W14, respectively. There were 11, 2 and 2 unique proteins in leaves, as well as 58, 9 and 12 unique proteins in storage roots for W14, SC205 and SC8, respectively, indicating proteomic changes in leaves and storage roots between cultivated cassava and its wild relatives. These proteins and their differential regulation across plants of contrasting leaf morphology, leaf anatomy pattern and photosynthetic related parameters and starch content could contribute to the footprinting of cassava domestication syndrome. We conclude that these global protein data would be of great value to detect the key gene groups related to cassava selection in the domestication syndrome phenomena

NMR and Raman Scattering Studies of Temperature- and Pressure-Driven Phase Transitions in CH3NH2NH2PbCl3 Perovskite

Three-dimensional methylhydrazinium (CH3NH2NH2+, MHy+) lead halides, related to the famous methylammonium (CH3NH3+, MA+) and formamidinium (CH(NH2)2+, FA) perovskites, are attractive optoelectronic materials crystallizing in polar structures. In this work, temperature-dependent 1H and 207Pb magic-angle spinning (MAS) NMR, Raman as well as high-pressure Raman studies of CH3NH2NH2PbCl3 (MHyPbCl3) are reported. Raman spectroscopy reveals many similarities between phonon properties of MHy lead halides and the MA and FA analogues. In particular, these families of compounds show an increase in wavenumber of cage modes when large I- ions are replaced by smaller Br- and then Cl- ones. They also show strong sensitivity of the CH3 torsional mode on size of the cavity occupied by MHy+ cation that decreases with decreasing size of the halide anion. The cage modes of MHyPbCl3 are, however, observed at significantly lower wavenumbers than similar modes of MAPbCl3 and FAPbCl3, indicating higher softness of MHyPbCl3. Temperature-dependent Raman and NMR studies demonstrate that the MHy+ cations in MHyPbCl3 are significantly less affected by the temperature-induced phase transition than the Pb-Cl framework. This suggests a displacive type of the phase transition dominated by tilting and deformation of the PbCl6 octahedra. Analysis of the 207Pb MAS NMR spectra reveals the presence of two differently distorted PbCl6 octahedra and diminishing (increasing) distortion of the less (more) distorted octahedra in the high-temperature phase. Pressure-dependent Raman studies reveal the presence of a single first-order pressure-induced phase transition between 0.72 and 1.27 GPa. Analysis of the spectra indicates that the driving forces for the pressure-induced phase transition in MHyPbCl3 are tilting and distortion of the PbCl6 octahedra accompanied by reorientation of MHy+ cations. Raman spectra do not show evidence of any additional phase transition or amorphization up to 6.95 GPa

Tumor cell nuclei soften during transendothelial migration

During cancer metastasis, tumor cells undergo significant deformation in order to traverse through endothelial cell junctions in the walls of blood vessels. As cells pass through narrow gaps, smaller than the nuclear diameter, the spatial configuration of chromatin must change along with the distribution of nuclear enzymes. Nuclear stiffness is an important determinant of the ability of cells to undergo transendothelial migration, yet no studies have been conducted to assess whether tumor cell cytoskeletal or nuclear stiffness changes during this critical process in order to facilitate passage. To address this question, we employed two non-contact methods, Brillouin confocal microscopy (BCM) and confocal reflectance quantitative phase microscopy (QPM), to track the changes in mechanical properties of live, transmigrating tumor cells in an in vitro collagen gel platform. Using these two imaging modalities to study transmigrating MDA-MB-231, A549, and A375 cells, we found that both the cells and their nuclei soften upon extravasation and that the nuclear membranes remain soft for at least 24 h. These new data suggest that tumor cells adjust their mechanical properties in order to facilitate extravasation

Tumor cell nuclei soften during transendothelial migration

During cancer metastasis, tumor cells undergo significant deformation in order to traverse through endothelial cell junctions in the walls of blood vessels. As cells pass through narrow gaps, smaller than the nuclear diameter, the spatial configuration of chromatin must change along with the distribution of nuclear enzymes. Nuclear stiffness is an important determinant of the ability of cells to undergo transendothelial migration, yet no studies have been conducted to assess whether tumor cell cytoskeletal or nuclear stiffness changes during this critical process in order to facilitate passage. To address this question, we employed two non-contact methods, Brillouin confocal microscopy (BCM) and confocal reflectance quantitative phase microscopy (QPM), to track the changes in mechanical properties of live, transmigrating tumor cells in an in vitro collagen gel platform. Using these two imaging modalities to study transmigrating MDA-MB-231, A549, and A375 cells, we found that both the cells and their nuclei soften upon extravasation and that the nuclear membranes remain soft for at least 24 h. These new data suggest that tumor cells adjust their mechanical properties in order to facilitate extravasation