OPC Specification Research Articles

Oligodendrocyte Development in the Absence of Their Target Axons In Vivo.

Oligodendrocytes form myelin around axons of the central nervous system, enabling saltatory conduction. Recent work has established that axons can regulate certain aspects of oligodendrocyte development and myelination, yet remarkably oligodendrocytes in culture retain the ability to differentiate in the absence of axons and elaborate myelin sheaths around synthetic axon-like substrates. It remains unclear the extent to which the life-course of oligodendrocytes requires the presence of, or signals derived from axons in vivo. In particular, it is unclear whether the specific axons fated for myelination regulate the oligodendrocyte population in a living organism, and if so, which precise steps of oligodendrocyte-cell lineage progression are regulated by target axons. Here, we use live-imaging of zebrafish larvae carrying transgenic reporters that label oligodendrocyte-lineage cells to investigate which aspects of oligodendrocyte development, from specification to differentiation, are affected when we manipulate the target axonal environment. To drastically reduce the number of axons targeted for myelination, we use a previously identified kinesin-binding protein (kbp) mutant, in which the first myelinated axons in the spinal cord, reticulospinal axons, do not fully grow in length, creating a region in the posterior spinal cord where most initial targets for myelination are absent. We find that a 73% reduction of reticulospinal axon surface in the posterior spinal cord of kbp mutants results in a 27% reduction in the number of oligodendrocytes. By time-lapse analysis of transgenic OPC reporters, we find that the reduction in oligodendrocyte number is explained by a reduction in OPC proliferation and survival. Interestingly, OPC specification and migration are unaltered in the near absence of normal axonal targets. Finally, we find that timely differentiation of OPCs into oligodendrocytes does not depend at all on the presence of target axons. Together, our data illustrate the power of zebrafish for studying the entire life-course of the oligodendrocyte lineage in vivo in an altered axonal environment.

Retinal determination genes coordinate neuroepithelial specification and neurogenesis modes in the Drosophila optic lobe.

Differences in neuroepithelial patterning and neurogenesis modes contribute to area-specific diversifications of neural circuits. In the Drosophila visual system, two neuroepithelia, the outer (OPC) and inner (IPC) proliferation centers, generate neuron subtypes for four ganglia in several ways. Whereas neuroepithelial cells in the medial OPC directly convert into neuroblasts, in an IPC subdomain they generate migratory progenitors by epithelial-mesenchymal transition that mature into neuroblasts in a second proliferative zone. The molecular mechanisms that regulate the identity of these neuroepithelia, including their neurogenesis modes, remain poorly understood. Analysis of Polycomblike revealed that loss of Polycomb group-mediated repression of the Hox gene Abdominal-B (Abd-B) caused the transformation of OPC to IPC neuroepithelial identity. This suggests that the neuroepithelial default state is IPC-like, whereas OPC identity is derived. Ectopic Abd-B blocks expression of the highly conserved retinal determination gene network members Eyes absent (Eya), Sine oculis (So) and Homothorax (Hth). These factors are essential for OPC specification and neurogenesis control. Finally, eya and so are also sufficient to confer OPC-like identity, and, in parallel with hth, the OPC-specific neurogenesis mode on the IPC.

Open CNC Machine Tool's State Data Acquisition and Application Based on OPC Specification

For open CNC machine tool, user can develop third-party software based on OPC specification. Besides, CNC machine tool produce massive state data in machining process, which real time reflect the states of the machine. In this paper, the structure of open numerical control system is introduced, then data acquisition and compression based on OPC specification is implemented, finally data mining of the status data and its application in the intelligent fault warning and diagnostic is proposed. This research is critical to realize the digit and smart factory.

Design of MOD-CAN Interface Card Based on OPC Technology

The actuality that SHCAN2000 system relies on FIX configuration software has limited its application scope significantly. In this paper, the interface card what accord with OPC specification was realized through applying LM3S8962 microcontroller and OPC technology, the opening performance of data acquisition system was greatly improved, which can effectively avoid the repeatability of development process and incompatibility of many integrated software systems, at the same time, the standardization of hardware and software was also fulfilled the requirements. The improved Field Bus control system has a broader application prospect in industrial control field.

Human oligodendrocytes from embryonic stem cells: conserved SHH signaling networks and divergent FGF effects

Human embryonic stem cells (hESCs) offer a platform to bridge what we have learned from animal studies to human biology. Using oligodendrocyte differentiation as a model system, we show that sonic hedgehog (SHH)-dependent sequential activation of the transcription factors OLIG2, NKX2.2 and SOX10 is required for sequential specification of ventral spinal OLIG2-expressing progenitors, pre-oligodendrocyte precursor cells (pre-OPCs) and OPCs from hESC-derived neuroepithelia, indicating that a conserved transcriptional network underlies OPC specification in human as in other vertebrates. However, the transition from pre-OPCs to OPCs is protracted. FGF2, which promotes mouse OPC generation, inhibits the transition of pre-OPCs to OPCs by repressing SHH-dependent co-expression of OLIG2 and NKX2.2. Thus, despite the conservation of a similar transcriptional network across vertebrates, human stem/progenitor cells may respond differently to those of other vertebrates to certain extrinsic factors.

The Uniform Engineering of Distributed Control Systems Using the OPC Specification

OPC specifications have considerably contributed to the uniformization and standardization procedures for the software applications gathering process data and exchanging it in a unitary ...

Using standard components in automation industry: A study on OPC Specification

This paper focuses on automation software integration issues based on standard OPC Components in the automation industry. OPC Specification is a set of published connectivity interfaces that enables integrators to connect disparate systems together. It has become de facto standard for the automation industry because of the widely acknowledged benefits it offers. In this paper, a typical multi-tier architecture of industrial automation system and the component-based SCADA software system are introduced simply at first. Then, an overview of OPC family and the issues on which individual OPC Specification focuses are presented. By carefully studying the reasons why OPC gets success in detail, it's first time as we know, from the point of definition, implementation, and usage of OPC Component, we propose some fairly impersonal opinions and get some valuable experiences. At last, an integration framework with OPC to the core and its integration approaches for constructing the distributed SCADA software system are described. The proposed integration solutions which use off-the-self OPC products available will enable integrators to create robust solutions and provide true interoperability while at the same time reducing implementation time and costs.

An extendable data engine based on OPC specification

This paper deals with the data exchange issue in the automation of power systems. We present a new concept of OPC-based data engine, including the formalization description, the unified data access (UDA) model and the implementation details. With the help of a simple UDA model, data sets, data sources and their relationships are described in a universal way; thus, a uniform process is achieved to access data from the model. The designed data engine greatly reduces the complexity of a system, working as a bridge between various data sources and applications. In particular, the OPC interfaces of a data engine provide an efficient, consistent way to exchange information with other applications. It can be seamlessly integrated into the applications that are compatible with the OPC specification. Evaluation results show that the performance and throughput of the designed data engine are quite satisfactory.