Reduction of spindle vibrations in milling machine by active magnetic bearing

In this study, a three-dimensional dynamic model of a milling machine is proposed. The cutting forces of the face milling process were obtained according to the cutting parameters by means of computer simulations and experiment. The cutting forces excited the dynamic model of the system. Relative displacements of the contact point of the cutting tool and the workpiece were obtained by using forced vibration analysis. These displacements affected machining accuracy of the milling machine. Therefore, radial and axial electromagnetic bearings were designed for the active control of the system and they were adapted on the spindle of the milling machine. Thereby the electromagnetic force produced around the rotating spindle reduced vibration amplitude of the cutting tool. The system was operated with and without active control and both these cases were compared. It was revealed that active control diminished cutting tool vibrations and improved machining performanc

Reduction of spindle vibrations in milling machine by active magnetic bearing

In this study, a three-dimensional dynamic model of a milling machine is proposed. The cutting forces of the face milling process were obtained according to the cutting parameters by means of computer simulations and experiment. The cutting forces excited the dynamic model of the system. Relative displacements of the contact point of the cutting tool and the workpiece were obtained by using forced vibration analysis. These displacements affected machining accuracy of the milling machine. Therefore, radial and axial electromagnetic bearings were designed for the active control of the system and they were adapted on the spindle of the milling machine. Thereby the electromagnetic force produced around the rotating spindle reduced vibration amplitude of the cutting tool. The system was operated with and without active control and both these cases were compared. It was revealed that active control diminished cutting tool vibrations and improved machining performanc

Reduction of spindle vibrations in milling machine by active magnetic bearing

In this study, a three-dimensional dynamic model of a milling machine is proposed. The cutting forces of the face milling process were obtained according to the cutting parameters by means of computer simulations and experiment. The cutting forces excited the dynamic model of the system. Relative displacements of the contact point of the cutting tool and the workpiece were obtained by using forced vibration analysis. These displacements affected machining accuracy of the milling machine. Therefore, radial and axial electromagnetic bearings were designed for the active control of the system and they were adapted on the spindle of the milling machine. Thereby the electromagnetic force produced around the rotating spindle reduced vibration amplitude of the cutting tool. The system was operated with and without active control and both these cases were compared. It was revealed that active control diminished cutting tool vibrations and improved machining performanc

Phosphorylation of serine-893 in CARD11 suppresses the formation and activity of the CARD11-BCL10-MALT1 complex in T and B cells

CARD 11 acts as a gatekeeper for adaptive immune responses after T cell or B cell antigen receptor (TCR/BCR) ligation on lymphocytes. PKC theta/beta-catalyzed phosphorylation of CARD11 promotes the assembly of the CARD11-BCL10-MALT1 (CBM) complex and lymphocyte activation. Here, we demonstrated that PKC theta/beta-dependent CARD11 phosphorylation also suppressed CARD11 functions in T or B cells. Through mass spectrometry-based proteomics analysis, we identified multiple constitutive and inducible CARD11 phosphorylation sites in T cells. We demonstrated that a single TCR- or BCR-inducible phosphorylation on Ser 893 in the carboxyl terminus of CARD1 1 prevented the activation of the transcription factor NF-kappa B, the kinase JNK, and the protease MALT1. Moreover, CARD11 Ser(893) phosphorylation sensitized BCR-addicted lymphoma cells to toxicity induced by Bruton's tyrosine kinase (BTK) inhibitors. Phosphorylation of Ser 893 in CARD11 by PKCO controlled the strength of CARD11 scaffolding by impairing the formation of the CBM complex. Thus, PKCO simultaneously catalyzes both stimulatory and inhibitory CARD11 phosphorylation events, which shape the strength of CARD11 signaling in lymphocytes

MALT1 Phosphorylation Controls Activation of T Lymphocytes and Survival of ABC-DLBCL Tumor Cells

The CARMA1/CARD11-BCL10-MALT1 (CBM) complex bridges T and B cell antigen receptor (TCR/BCR) ligation to MALT1 protease activation and canonical nuclear factor kappa B (NF-kappa B) signaling. Using unbiased mass spectrometry, we discover multiple serine phosphorylation sites in the MALT1 C terminus after T cell activation. Phospho-specific antibodies reveal that CBM-associated MALT1 is transiently hyper-phosphorylated upon TCR/CD28 co-stimulation. We identify a dual role for CK1 alpha as a kinase that is essential for CBM signalosome assembly as well as MALT1 phosphorylation. Although MALT1 phosphorylation is largely dispensable for protease activity, it fosters canonical NF-kappa B signaling in Jurkat and murine CD4 T cells. Moreover, constitutive MALT1 phosphorylation promotes survival of activated B cell-type diffuse large B cell lymphoma (ABC-DLBCL) cells addicted to chronic BCR signaling. Thus, MALT1 phosphorylation triggers optimal NF-kappa B activation in lymphocytes and survival of lymphoma cells

A reversible state of hypometabolism in a human cellular model of sporadic Parkinson's disease

Sporadic Parkinson's Disease (sPD) is a progressive neurodegenerative disorder caused by multiple genetic and environmental factors. Mitochondrial dysfunction is one contributing factor, but its role at different stages of disease progression is not fully understood. Here, we showed that neural precursor cells and dopaminergic neurons derived from induced pluripotent stem cells (hiPSCs) from sPD patients exhibited a hypometabolism. Further analysis based on transcriptomics, proteomics, and metabolomics identified the citric acid cycle, specifically the alpha-ketoglutarate dehydrogenase complex (OGDHC), as bottleneck in sPD metabolism. A follow-up study of the patients approximately 10 years after initial biopsy demonstrated a correlation between OGDHC activity in our cellular model and the disease progression. In addition, the alterations in cellular metabolism observed in our cellular model were restored by interfering with the enhanced SHH signal transduction in sPD. Thus, inhibiting overactive SHH signaling may have potential as neuroprotective therapy during early stages of sPD. Mitochondrial dysfunction is a contributing factor in Parkinson's disease. Here the authors carry out a multilayered omics analysis of Parkinson's disease patient-derived neuronal cells, which reveals a reversible hypometabolism mediated by alpha-ketoglutarate dehydrogenase deficiency, which is correlated with disease progression in the donating patients

Cassini Radio Science

Cassini radio science investigations will be conducted both during the cruise (gravitational wave and conjunction experiments) and the Saturnian tour of the mission (atmospheric and ionospheric occultations, ring occultations, determinations of masses and gravity fields). New technologies in the construction of the instrument, which consists of a portion on-board the spacecraft and another portion on the ground, including the use of the Ka-band signal in addition to that of the S- and X-bands, open opportunities for important discoveries in each of the above scientific areas, due to increased accuracy, resolution, sensitivity, and dynamic range.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43765/1/11214_2004_Article_1436.pd