1,058 research outputs found

    HMGB1 Redox During Sepsis

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    During sepsis, the alarmin HMGB1 is released from tissues and promotes systemic inflammation that results in multi-organ damage, with the kidney particularly susceptible to injury. The severity of inflammation and pro-damage signaling mediated by HMGB1 appears to be dependent on the alarmin\u27s redox state. Therefore, we examined HMGB1 redox in kidney cells during sepsis. Using intravital microscopy, CellROX labeling of kidneys in live mice indicated increased ROS generation in the kidney perivascular endothelium and tubules during lipopolysaccharide (LPS)-induced sepsis. Subsequent CellROX and MitoSOX labeling of LPS-stressed endothelial and kidney proximal tubule cells demonstrated increased ROS generation in these cells as sepsis worsens. Consequently, HMGB1 oxidation increased in the cytoplasm of kidney cells during its translocation from the nucleus to the circulation, with the degree of oxidation dependent on the severity of sepsis, as measured in in vivo mouse samples using a thiol assay and mass spectrometry (LC-MS/MS). The greater the oxidation of HMGB1, the greater the ability of the alarmin to stimulate pro-inflammatory cyto-/chemokine release (measured by Luminex Multiplex) and alter mitochondrial ATP generation (Luminescent ATP Detection Assay). Administration of glutathione and thioredoxin inhibitors to cell cultures enhanced HMGB1 oxidation during sepsis in endothelial and proximal tubule cells, respectively. In conclusion, as sepsis worsens, ROS generation and HMGB1 oxidation increases in kidney cells, which enhances HMGB1\u27s pro-inflammatory signaling. Conversely, the glutathione and thioredoxin systems work to maintain the protein in its reduced state

    Dynamics of zonal flow-like structures in the edge of the TJ-II stellarator

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    The dynamics of fluctuating electric field structures in the edge of the TJ-II stellarator, that display zonal flow-like traits, is studied. These structures have been shown to be global and affect particle transport dynamically [J.A. Alonso et al., Nucl. Fus. 52 063010 (2012)]. In this article we discuss possible drive (Reynolds stress) and damping (Neoclassical viscosity, geodesic transfer) mechanisms for the associated ExB velocity. We show that: (a) while the observed turbulence-driven forces can provide the necessary perpendicular acceleration, a causal relation could not be firmly established, possibly because of the locality of the Reynolds stress measurements, (b) the calculated neoclassical viscosity and damping times are comparable to the observed zonal flow relaxation times, and (c) although an accompanying density modulation is observed to be associated to the zonal flow, it is not consistent with the excitation of pressure side-bands, like those present in geodesic acoustic oscillations, caused by the compression of the ExB flow field

    A Stop Codon in Xeroderma Pigmentosum Group C Families in Turkey and Italy: Molecular Genetic Evidence for a Common Ancestor

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    Xeroderma pigmentosum family G from Van, Turkey had two severely affected children: a son with multiple skin cancers who died at age 10 (XP67TMA), and an 8 y old daughter who began developing skin cancer before 3 y of age (XP68TMA). XP67TMA and XP68TMA cells were hypersensitive to killing by ultraviolet and the post-ultraviolet DNA repair level was 12–16% of normal. Host cell reactivation of an ultraviolet-treated reporter plasmid cotransfected with a vector expressing wild-type XPC cDNA assigned XP67TMA to xeroderma pigmentosum complementation group C. The XPC mRNA level was markedly reduced. Sequencing of the 3.5 kb XPC cDNA from XP67TMA showed a C–T mutation in XPC exon 8 at base pair 1840. This mutation converts the CGA codon of arginine at amino acid 579 to a UGA stop codon resulting in marked truncation of the 940 amino acid xeroderma pigmentosum C protein. Restriction fragment length polymorphism analysis of XPC exon 8 DNA in XP67TMA and XP68TMA showed that both affected children had a homozygous mutation and that both parents had heterozygous normal and mutated sequences at the same position consistent with a history of consanguinity in the family. The mutated allele also contained two XPC single nucleotide polymorphisms. The same mutated XPC allele was reported in an Italian family. Studies of 19 microsatellite markers flanking the XPC gene on chromosome 3 suggest that the XPC allele passed between Italy and Turkey approximately 300–500 y ago. This XPC allele containing a nonsense mutation is associated with severe clinical disease with multiple skin cancers and early death

    Real-time plasma state monitoring and supervisory control on TCV

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    In ITER and DEMO, various control objectives related to plasma control must be simultaneously achieved by the plasma control system (PCS), in both normal operation as well as off-normal conditions. The PCS must act on off-normal events and deviations from the target scenario, since certain sequences (chains) of events can precede disruptions. It is important that these decisions are made while maintaining a coherent prioritization between the real-time control tasks to ensure high-performance operation. In this paper, a generic architecture for task-based integrated plasma control is proposed. The architecture is characterized by the separation of state estimation, event detection, decisions and task execution among different algorithms, with standardized signal interfaces. Central to the architecture are a plasma state monitor and supervisory controller. In the plasma state monitor, discrete events in the continuous-valued plasma state arc modeled using finite state machines. This provides a high-level representation of the plasma state. The supervisory controller coordinates the execution of multiple plasma control tasks by assigning task priorities, based on the finite states of the plasma and the pulse schedule. These algorithms were implemented on the TCV digital control system and integrated with actuator resource management and existing state estimation algorithms and controllers. The plasma state monitor on TCV can track a multitude of plasma events, related to plasma current, rotating and locked neoclassical tearing modes, and position displacements. In TCV experiments on simultaneous control of plasma pressure, safety factor profile and NTMs using electron cyclotron heating (ECI I) and current drive (ECCD), the supervisory controller assigns priorities to the relevant control tasks. The tasks are then executed by feedback controllers and actuator allocation management. This work forms a significant step forward in the ongoing integration of control capabilities in experiments on TCV, in support of tokamak reactor operation.Peer reviewe
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