]cyt) response in tumor-derived SW982 synoviocytes and primary cultures of human synovial cells from patients with inflammatory arthropathies. As shown by fura-2 ratio measurements while cells were incubated in a temperature-regulated chamber, significant [Ca 2ϩ ]cyt elevation was elicited by rapid changes in bath temperature, application of TRPV1 receptor agonists capsaicin and resiniferatoxin, or a cold receptor stimulator, icilin. Temperature thresholds for calcium response were determined to be 12 Ϯ 1°C for cold and 28 Ϯ 2°C for heat activation. Temperature increases or decreases beyond these thresholds resulted in a significant rise in the magnitude of [Ca 2ϩ ]cyt spikes. Observed changes in [Ca 2ϩ ]cyt were completely abolished in calcium-free medium and thus resulted from direct calcium entry through TRP channels rather then by activation of voltage-dependent calcium channels. Two heat sensitive channels, TRPV1 and TRPV4, and a cold-sensitive channel, TRPA1, were detected by RT-PCR. Minimal mRNA for TRPV3 or TRPM8 was amplified. The RT-PCR results support the data obtained with the [Ca 2ϩ ]cyt measurements. We propose that the TRP channels are functionally expressed in human synoviocytes and may play a critical role in adaptive or pathological changes in articular surfaces during arthritic inflammation. transient receptor potential channels; vanilloid receptors; arthritis CELLS IN SYNOVIAL COMPARTMENTS can be exposed to low pH conditions after inflammation, infection, or injury. An acidsensing G protein-coupled receptor has been identified on synovial cells that are responsive to low pH (pH 5.5-7.0) in calcium-free media except in the presence of Cu 2ϩ (6). A response profile in low pH (pH 7.0 -7.2) in the presence of Cu 2ϩ was also noted, consistent with transient receptor potential (TRP)V1 activation. The present study was designed to characterize TRP receptors on target human synovial cells. The presence of TRP receptors on target peripheral tissue would be an adaptive mechanism for activating intracellular responses outside the physiological range.The TRP ion channels are important membrane sensors, responding to thermal, chemical, osmotic, or mechanical stimuli by activation of calcium and sodium fluxes. Currently, the mammalian TRP family consists of 28 unique channels, in 6 main subfamilies (43). Recent studies demonstrated that several members of TRP V, M, and A subfamilies act as the thermal sensation receptors, responding to moderate or noxious changes in the external temperature. These channels are called "heat" or "cold" receptors, depending on the temperature range required for their activation.
Nearly monodisperse PbWO4 and CaWO4 microspheres have been synthesized in large scale by a surfactant-assisted solution route, in which either sodium dodecyl benzenesulfonate (SDS) or cetyltrimethyl ammonium bromide (CTAB) is used. By controlling the solution reaction conditions, such as temperature, surfactant, and pH value, we can synthesize nearly monodisperse microspheres of tetragonal tungstate (MWO4, M = Pb, Ca) composed of subunits with different shapes. The diameters of these microspheres have been found to be sensitive to the reaction conditions and could be tuned by controlling the reaction conditions. The growth process of these nearly monodisperse microspheres has been examined. The optical properties of the tungstate monodisperse microspheres in the temperature range of 20−270 K were studied.
ions were prepared by a solid state reaction technique at high temperature. The excitation spectra in the VUV (vacuum ultraviolet)-UV range and the emission spectra in the UV-vis range together with decay time spectra are investigated and discussed. X-ray excited emission spectra were measured and light yields are calculated. The results revealed that Ca(II) sites are preferentially occupied at low doping concentration, and then Ca(I) sites are dominant with the increasing of concentration for Ce 3+ in Ca 5 (PO 4 ) 3 F. In contrast, Ce 3+ ions mainly occupied the Sr(II)/Ba(II) sites in Sr 5 (PO 4 ) 3 F and Ba 5 (PO 4 ) 3 F even at higher doping concentration. The low light output seems to suggest that the materials are not suitable x-ray or gamma-ray phosphors.
The VUV-vis spectroscopic properties of Gd 3+ in Na(Y,Gd)FPO 4 are reported. The photon cascade emission was observed under 8 S 7/2 f 6 G J excitation in which 6 G J f 6 P J , 6 I J emissions of Gd 3+ in the orange/red and near-IR range are followed by ultraviolet emission of 6 P J f 8 S 7/2 transitions. We demonstrate systematically the emission decays and concentration-quenching characteristics of 6 G J f 6 P J and 6 P J f 8 S 7/2 transitions under excitation into 6 G J levels. The effect of temperature on the 6 G J f 6 P J emissions is also presented. IntroductionPhosphors for excitation in the VUV (vacuum ultraviolet, wavelength λ < 200 nm, energy E > 50 000 cm -1 ) region are required for application in Hg-free fluorescent tubes and plasma display panels (PDPs). Development of VUV phosphors, especially excitation upon 147 and 172 nm (xenon discharge emission wavelength), has become an important challenge in the field of luminescent materials. There is a higher nonradiative relaxation energy loss (65% loss for a 172 nm photon), 1 which is involved in conversion of a photon with higher energy in the vacuum ultraviolet range to a photon with lower energy in the visible region. In order to improve the energy efficiency, the most feasible approach is by quantum cutting or photon cascade emission (PCE), 2,3 that is, the phosphor absorbs one vacuum ultraviolet photon and emits two or more visible photons.Early in 1957 the possibility for PCE was discussed by Dexter. 4 Since the 1970s the PCE process was first demonstrated by Pr 3+ in fluorides 5,6 and then in borates and other oxides. [7][8][9] Recently, the photon cascade emission of Gd 3+ was also observed in LiYF 4 10 and GdBaB 9 O 16 11 when Gd 3+ was excited to 6 G J states. More important, the quantum cutting can also be achieved using a combination of two lanthanide ions, for example, Gd 3+ -Eu 3+ or Gd 3+ -Nd 3+ /Tm 3+ in fluorides, and the high-lying energy levels 6 G J of Gd 3+ play a key role in these quantum cutting processes. 2,12 Fluorides usually show lower effective phonon frequencies, but they also have a crucial shortcoming. That is, they have no efficient absorption around 147/172 nm. Oxides are maybe better matrices than fluorides for VUV phosphors because of their easy preparation, better physical and chemical stability, and higher VUV absorption efficiency, but their higher phonon frequency usually causes higher nonradiative relaxation energy loss. Therefore, Na(Y,Gd)FPO 4 is selected as the host, which is expected to combine the good qualities of fluorides and oxides. This paper will focus on the photon cascade emission of Gd 3+ in Na(Y,Gd) FPO 4 . NaYFPO 4 13 is crystallized in the monoclinic system (space group C 2/m ) with unit cell parameters a ) 8.944(2) Å, b )
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