Pharmacological Inhibition of Voltage-gated Ca2+ Channels for Chronic Pain Relief

Chronic pain is a major therapeutic problem as the current treatment options are unsatisfactory with low efficacy and deleterious side effects. Voltage-gated Ca2+ channels (VGCCs), which are multi-complex proteins consisting of α1, β, γ, and α2δ subunits, play an important role in pain signaling. These channels are involved in neurogenic inflammation, excitability, and neurotransmitter release in nociceptors. It has been previously shown that N-type VGCCs (Cav2.2) are a major pain target. U.S. FDA approval of three Cav2.2 antagonists, gabapentin, pregabalin, and ziconotide, for chronic pain underlies the importance of this channel subtype. Also, there has been increasing evidence that L-type (Cav1.2) or T-type (Cav3.2) VGCCs may be involved in pain signaling and chronic pain. In order to develop novel pain therapeutics and to understand the role of VGCC subtypes, discovering subtype selective VGCC inhibitors or methods that selectively target the inhibitor into nociceptors would be essential. This review describes the various VGCC subtype inhibitors and the potential of utilizing VGCC subtypes as targets of chronic pain. Development of VGCC subtype inhibitors and targeting them into nociceptors will contribute to a better understanding of the roles of VGCC subtypes in pain at a spinal level as well as development of a novel class of analgesics for chronic pain

Application of microperforated elements in axial fan noise control and silencer design

The microperforated panel (MPP) is considered to be an alternative sound absorbing material, which could replace the traditional glass fibers and other porous materials because of its sound absorbing characteristics in a wide frequency range. The MPP is also very useful in various human involved environments because it is less harmful to human respiratory system than traditional sound absorbing materials, meaning more hygienic. Therefore in this study, microperforated panels were used in fan noise control and in acoustic silencers, where both of the devices are easily accessible by humans

The application of microperforated material to control axial fan noise

In this paper, a passive fan noise control approach implemented by applying microperforated materials to the shroud of an axial fan will be discussed. Microperforated panels with different flow resistances were compared to an unperforated fan housing. In addition to the shroud treatment, the application of an extended microperforated housing to the inlet-end and outlet end of the fan will be discussed

The Application of Microperforated Panels in Duct Systems

Microperforated panels (MPPs) are usually considered to be an alternative sound absorbing surface treatment in architectural acoustics applications, where they can serve as effective, fiber-free replacements for the more traditional glass fibers and other porous materials. However, the areas in which MPPs may be applied are not only limited to the replacement of conventional sound absorbing materials, but MPPs can also be used in spaces where more conventional materials cannot be conveniently used. For example, heating, ventilation, and air conditioning (HVAC) duct application is one area where MPPs can be used as a stand-alone material,in contrast with glass fiber, which typically must be covered by perforated surface treatments to prevent erosion of the fibers due to the flow. In this study, it will be shown how a suitably designed MPP can be an effective noise control element in ducts by reducing fan and flow noise while at the same time maintaining the flow delivery performance of the duct