Design of multivariable feedback control systems via spectral assignment using reduced-order models and reduced-order observers

The feasibility of using reduced order models and reduced order observers with eigenvalue/eigenvector assignment procedures is investigated. A review of spectral assignment synthesis procedures is presented. Then, a reduced order model which retains essential system characteristics is formulated. A constant state feedback matrix which assigns desired closed loop eigenvalues and approximates specified closed loop eigenvectors is calculated for the reduced order model. It is shown that the eigenvalue and eigenvector assignments made in the reduced order system are retained when the feedback matrix is implemented about the full order system. In addition, those modes and associated eigenvectors which are not included in the reduced order model remain unchanged in the closed loop full order system. The fulll state feedback design is then implemented by using a reduced order observer. It is shown that the eigenvalue and eigenvector assignments of the closed loop full order system remain unchanged when a reduced order observer is used. The design procedure is illustrated by an actual design problem

Design of multivariable feedback control systems via spectral assignment using reduced-order models and reduced-order observers

The feasibility of using reduced order models and reduced order observers with eigenvalue/eigenvector assignment procedures is investigated. A review of spectral assignment synthesis procedures is presented. Then, a reduced order model which retains essential system characteristics is formulated. A constant state feedback matrix which assigns desired closed loop eigenvalues and approximates specified closed loop eigenvectors is calculated for the reduced order model. It is shown that the eigenvalue and eigenvector assignments made in the reduced order system are retained when the feedback matrix is implemented about the full order system. In addition, those modes and associated eigenvectors which are not included in the reduced order model remain unchanged in the closed loop full order system. The full state feedback design is then implemented by using a reduced order observer. It is shown that the eigenvalue and eigenvector assignments of the closed loop full order system rmain unchanged when a reduced order observer is used. The design procedure is illustrated by an actual design problem

Sonication-Assisted Synthesis of β-Mercuric Sulfide Nanoparticles

The nanoscale semiconductor β‐mercuric sulphide (HgS) has promising applications in electronic and optical fields. Continued development of synthesis methods is needed to expand approaches that produce uniform particles, while avoiding reagents of high toxicity and ecological impact. A solvent‐based approach was developed using mercuric chloride and elemental sulphur as the mercury and chalcogenide sources. Ethanol was used as the solvent and sodium hydroxide as the hydrolysis reagent. Use of mild sonication resulted in smaller particles (average 11nm diameter) than without sonication treatment (average 17nm diameter) and continuous nitrogen purging reduced the surface oxygen content of the particles from approximately 25% to 6%. Particle characterization methods included TEM, XRD, XPS, UV‐visible absorbance spectroscopy and DLS. The nanoparticles were typically spheres of 10‐15nm in diameter. Aggregates formed in aqueous solutions tended to be in the range of 100nm or more. The overall process can be performed simply at room temperature and is comparatively free of toxic chemical hazards. The process does not include surfactants or other stabilizers that could potentially contaminate the nanocrystals. In principle, the method could be applied to synthesis of other metal chalcogenide nanoparticles

Convective response of a wall-mounted hot-film sensor in a shock tube

Shock tube experiments were performed in order to determine the response of a single hot-film element of a sensor array to transiently induced flow behind weak normal shock waves. The experiments attempt to isolate the response due only to the change in convective heat transfer at the hot-film surface mounted on the wall of the shock tube. The experiments are described, the results being correlated with transient boundary layer theory and compared with an independent set of experimental results. One of the findings indicates that the change in the air properties (temperature and pressure) precedes the air mass transport, causing an ambiguity in the sensor response to the development of the velocity boundary layer. Also, a transient, local heat transfer coefficient is formulated to be used as a forcing function in an hot-film instrument model and simulation which remains under investigation

Galectin-3 regulates intracellular trafficking of EGFR through Alix and promotes keratinocyte migration.

The EGFR-mediated signaling pathways are important in a variety of cellular processes, including cell migration and wound re-epithelialization. Intracellular trafficking of EGFR is critical for maintaining EGFR surface expression. Galectin-3, a member of an animal lectin family, has been implicated in a number of physiological and pathological processes. Through studies of galectin-3-deficient mice and cells isolated from these mice, we demonstrated that the absence of galectin-3 impairs keratinocyte migration and skin wound re-epithelialization. We have linked this pro-migratory function to a crucial role of cytosolic galectin-3 in controlling intracellular trafficking and cell surface expression of EGFR after EGF stimulation. Without galectin-3, the surface levels of EGFR are markedly reduced, and the receptor accumulates diffusely in the cytoplasm. This is associated with reduced rates of both endocytosis and recycling of the receptor. We have provided evidence that this previously unreported function of galectin-3 may be mediated through interaction with its binding partner Alix, which is a protein component of the ESCRT (endosomal sorting complex required for transport) machinery. Our results suggest that galectin-3 is potentially a critical regulator of a number of important cellular responses through its intracellular control of trafficking of cell surface receptors

Relationships Between Metal Contamination in Wadable Streams in South Carolina and Land Use Charateristics

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

Characterization of METTL16 as a cytoplasmic RNA binding protein

mRNA modification by N6-methyladenosine (m6A) is involved in many post-transcriptional regulation processes including mRNA stability, splicing and promotion of translation. Accordingly, the recently identified mRNA methylation complex containing METTL3, METTL14, and WTAP has been the subject of intense study. However, METTL16 (METT10D) has also been identified as an RNA m6A methyltransferase that can methylate both coding and noncoding RNAs, but its biological role remains unclear. While global studies have identified many potential RNA targets of METTL16, only a handful, including the long noncoding RNA MALAT1, the snRNA U6, as well as the mRNA MAT2A have been verified and/or studied to any great extent. In this study we identified/verified METTL16 targets by immunoprecipitation of both endogenous as well as exogenous FLAG-tagged protein. Interestingly, exogenously overexpressed METTL16 differed from the endogenous protein in its relative affinity for RNA targets which prompted us to investigate METTL16’s localization within the cell. Surprisingly, biochemical fractionation revealed that a majority of METTL16 protein resides in the cytoplasm of a number of cells. Furthermore, siRNA knockdown of METTL16 resulted in expression changes of a few mRNA targets suggesting that METTL16 may play a role in regulating gene expression. Thus, while METTL16 has been reported to be a nuclear protein, our findings suggest that METTL16 is also a cytoplasmic methyltransferase that may alter its RNA binding preferences depending on its cellular localization. Future studies will seek to confirm differences between cytoplasmic and nuclear RNA targets in addition to exploring the physiological role of METTL16 through long-term knockdown

N6-methyladenosine contributes to cellular phenotype in a genetically-defined model of breast cancer progression

The mRNA modification N6-methyladenosine (m6A) is involved in many post- transcriptional regulatory processes including mRNA stability and translational efficiency. However, it is also imperative to correlate these processes with phenotypic outputs during cancer progression. Here we report that m6A levels are significantly decreased in genetically-defined immortalized and oncogenically-transformed human mammary epithelial cells (HMECs), as compared with their primary cell predecessor. Furthermore, the m6A methyltransferase (METTL3) is decreased and the demethylase (ALKBH5) is increased in the immortalized and transformed cell lines, providing a possible mechanism for this basal change in m6A levels. Although the immortalized and transformed cells showed lower m6A levels than their primary parental cell line, overexpression of METTL3 and METTL14, or ALKBH5 knockdown to increase m6A levels in transformed cells increased proliferation and migration. Remarkably, these treatments had little effect on the immortalized cells. Together, these results suggest that m6A modification may be downregulated in immortalized cells as a brake against malignant progression. Finally, we found that m6A levels in the immortalized and transformed cells increased in response to hypoxia without corresponding changes in METTL3, METTL14 or ALKBH5 expression, suggesting a novel pathway for regulation of m6A levels under stress