Tumor necrosis factor (TNF)-family cytokines induce reactive oxygen species (ROS) that injure vulnerable populations of brain cells. Among glia, oligodendrocytes are particularly susceptible to TNF-induced ROS whereas microglia are protected. We previously found that oligodendrocytes in vitro predominantly express the p55 type-1 TNF receptor, while microglial cells express both type-1 and p75 type-2 receptors. We hypothesized that differential TNF receptor expression and attendant signaling underlies the relative vulnerability of oligodendrocytes, versus microglia, to TNF-induced injury. To test this hypothesis, purified cultures of glial cells were incubated 0–48 hr with TNFa or lymphotoxin-alpha, following which levels of ROS, glutathione (GSH), nuclear factor kappa-B (NFκB) translocation, and anti-oxidant proteins and activity were measured. 48 hr exposure to TNF increased ROS levels 28% and decreased GSH levels 17% in oligodendrocytes, but decreased levels ROS levels 24% and increased GSH levels 112% increase in microglia. Thirty to 180 min exposure to TNF increased NFkB nuclear translocation to a greater extent and for a longer time in microglia versus oligodendrocytes, and this was followed 24–48 hr later with 3- to 13-fold increases in microglia manganese superoxide dismutase protein levels and 6-fold increases in enzyme activity. Collectively, these data suggest that signals transduced through the p75 receptor activate anti-oxidant mechanisms that protect microglia from TNF-induced injury. Lacking such signals, oligodendrocytes are considerably more vulnerable to the injurious effects of TNF.
A apparatus for forming a beverage using a beverage formation device. Opening of a brew chamber may automatically enable the provision of beverage precursor liquid from a reservoir to a heating tank that is used (heated or not) to form a beverage. For example, opening of the brew chamber may cause a valve to be opened or otherwise permit flow of beverage precursor liquid from the reservoir to the heating tank. The valve may open simultaneously and automatically with a brew chamber lid, and may close when the brew chamber lid is closed.
An assembly adapted to emit electromagnetic radiation made up of an emitter of electromagnetic radiation; a non-reflective ceramic support for the emitter; a substantially transparent crown mounted on the support to define and enclose a space that houses the emitter; and leads attached to the emitter through the support. The combination of the non-reflective support and the transparent crown, and the location of the emitter in the enclosed space enables the emitter to emit electromagnetic radiation in a conical radiation pattern. The radiation pattern appears to have a centroid. This centroid appears to be in a more constant spatial position regardless of the viewing angle as compared with the apparent position of this centroid with other assemblies.
An valve actuator in a hydronic heating and cooling system includes a motor for changing the position of a valve, a switch for switching power to the motor, and a sensor for detecting the arrival of the valve at a desired position and for stopping the motor without using a mechanical stop. The motor's power source includes a capacitive power source which can be used to drive the motor under low-power conditions. A worm gear is used in the drive train, and combined with a clutch assembly to permit the valve to be operated manually.
A tunnel-type conveyor oven having two types of heat sources is provided. The oven includes a conveyor for carrying items through the oven along a conveyor path. The conveyor has first and second opposite sides. A plurality of radiant heaters are located transverse to and extend across the conveyor path. The radiant heaters are spaced apart in a direction of the conveyor path. Each radiant heater includes an inner tube having a wall with a plurality of openings defined therethrough, an open first end and a second end. A burner is directed into the open first end of the inner tube. An outer tube is located around the inner tube. The outer tube has an outer surface which is adapted to radiate heat, a first end and a second end. An exhaust outlet is located on the second end of the outer tube. The radiant heaters are arranged such that with every other heater, the burners are located on the first side of the conveyor, and with the remaining heaters, the burners are located on the second side of the conveyor for uniform radiant heat distribution across the conveyor. An exhaust manifold is connected to the exhaust outlet of at least one of the heaters. A penthouse chamber is located above the plurality of radiant heaters, and the exhaust manifold is connected to the penthouse chamber. A convection heating system is also provided which includes an upper convection heater located above and extending across the conveyor path. The upper convection heater has an upper plenum with supply areas located between each of the radiant heaters. The supply areas each have a plurality of openings directed toward the conveyor path. A lower convection heater is located below the conveyor path and includes a lower plenum having a plurality of openings directed toward the conveyor path. A convection air manifold is connected between the penthouse chamber and the upper and lower plenums to deliver the products of combustion from the radiant heaters collected in the penthouse chamber to the upper and lower plenums to provide convective heat along the conveyor path.
Improved point source electromagnetic radiation emitters including a dispersing element that radiates electromagnetic radiation over a very wide conical angle of approaching about 180.degree.. This light dispersing element can be in any one or more of several illustrated forms such as a light diffusing spherical or hemispherical element, a planar diffusing plate, a tapered light guide, a plano-concave lens, a convex mirror, a light pipe with a large numerical aperture, or the like. The emitter of this invention may be fixed to an object and tracked in a 3-dimensional volume by a system using electro-optical position sensors in order to determine the spatial location of the emitters and therefore to determine, by geometry, the position and orientation of the object. The electromagnetic radiation generator is preferably disposed remote from the emitter and is electrically and magnetically isolated from the emitter. A common optical fiber provides transmission of the radiation from the generator to the emitter. The emitted radiation more nearly resembles point source of radiation and therefore enables more accurate determination of the location of the radiating element, and thereby more accurate determination of the position and orientation of the object on which the emitters reside. The preferred electromagnetic radiation generator is an LED, most preferably a laser diode.