Analytical model of a diode-pumped cesium laser for investigation of upper-state mixing and quenching reactions.

A one-dimensional analytical model of a diode-pumped cesium vapor laser was constructed, and equations were derived to explain the dependence of the laser power on the hydrocarbon gas partial pressure. By varying the hydrocarbon gas partial pressure over a wide range and measuring the laser power, the corresponding mixing and quenching rate constants were validated. A gas-flow Cs diode-pumped alkali laser (DPAL) was operated with methane, ethane, and propane as buffer gases, with the partial pressures varied from 0 to 2 atmospheres. The experimental results were found to be in good agreement with the analytical solutions, confirming the validity of our proposed method. Separate 3-D numerical simulations were performed, and the output power effectively reproduced the experimental results over the entire buffer gas pressure range.

[Utility of microsemi LC-667CRP in point of care testing system for acute inflammatory disease].

We examined the basic performance of "Microsemi LC-667CRP" (LC-667, HORIBA, Ltd.) which has been newly developed as compact laboratory instrument capable of simultaneous measuring of complete blood count (CBC) including 3-part differentials of white blood cells (WBC) and C-reactive protein (CRP) using whole blood anticoagulated with ethylenediaminetetraacetic acid (EDTA). We found that CBC and CRP were intra-assay-reproducible (n = 10, CVs < 5.0%). They also showed the good linearity and no definite carry-over. Concerning the WBC differentials, percentage of monocytes (MON%) showed less intra-assay reproducibility compared with those of granulocytes (GRA%) and lymphocytes (LYM%). We also evaluated the correlation of values obtained by LC-667 and routinely used instruments in our institute. Concerning the CBC and WBC differentials, excellent correlations were found between LC-667CRP and XE-2100 (SYSMEX CORPORATION) except MON%. In addition, whole blood CRP as well as plasma and serum CRP measured by LC-667 also showed the good correlations with serum CRP measured by 7600 (Hitachi High Technologies Corporation). From these findings, LC-667 was revealed to produce the clinically reliable data using only 18 microL of sample volume in 4 minutes. Point of care testing (POCT) has been developed as the laboratory system performed at or near the site of patient to reduce the turn around time. Therefore, LC-667 seemed useful in POCT for the patients with acute inflammatory disease especially in pediatrics.

Cleft-type cyclophanes confer neuroprotection against excitatory neurotoxicity in vitro and in vivo through inhibition of NMDA receptors.

The cleft-type cyclophanes (ACCn, DNCn and TsDCn) were found to strongly inhibit macroscopic currents at heteromeric NMDA receptors (NR1/NR2) but not AMPA receptors expressed in Xenopus oocytes at voltage-clamp recording. The inhibition by cleft-type cyclophanes was voltage-dependent, because the inhibition was larger at -100 mV than at -20 mV. Mutations at NR1 N650, located in the vestibule of the channel pore, reduced the inhibition by DNCn and TsDCn, suggesting that the residue (N650) interacts with these cleft-type cyclophanes. Cell toxicity of TsDCn on SH-SY5Y cells was slightly weaker than that of memantine. The neuroprotective effects of cleft-type cyclophanes against cell damage caused by NMDA were investigated in cultured rat hippocampal neurons. Addition of 10 microM DNCn or TsDCn into the medium ablated the neurotoxicity induced by NMDA, and a similar effect was also observed with memantine. The neuroprotective effects of cleft-type cyclophanes were then assayed on NMDA-induced seizures in mice. Intracerebroventricular injection of TsDCn (5 mg/mouse) decreased the seizure induced by intraperitoneal injection of NMDA (115 mg/kg) in mice. The results demonstrate that these cleft-type cyclophanes interact directly with the extracellular mouth of the NMDA channel pore and exhibit neuroprotective effects on NMDA-induced excitatory toxicity in primary cultured neurons and mice.

Cyclophane and acyclic cyclophane: novel channel blockers of N-methyl-D-aspartate receptor.

The effects of cyclophanes (CPCn, CPPy and TGDMAP) and acyclic cyclophane (ATGDMAP) on various glutamate receptors were studied with these receptors expressed in Xenopus oocytes using voltage-clamp recording. CPCn, CPPy, TGDMAP and ATGDMAP were found to inhibit macroscopic currents at heteromeric NMDA receptors (NR1/NR2), but not Ca(2+)-permeable AMPA receptors (GluR1), Ca(2+)-nonpermeable AMPA receptors (GluR1/GluR2) and metabotropic glutamate receptors (mGluR1alpha). The inhibition of NR1/NR2A receptors by these compounds was more potent than those of the other NMDA receptor subtypes. At a resting potential (-70 mV), the IC(50) values of CPCn, CPPy, TGDMAP and ATGDMAP for NR1/NR2A receptors were 0.5+/-0.1, 1.0+/-0.2, 8.0+/-0.8 and 4.9+/-0.5 microM, respectively. The inhibition by these compounds was voltage-dependent, that is, the degree of inhibition was in the order of negative holding potentials, -100 mV>-70 mV>-20 mV. Results of experiments using mutant NR1 and NR2 subunits identified residues that influence block by CPCn. The inhibition by CPCn was not altered significantly in the mutants at the critical asparagines in the M2 loop, NR1 N616, NR2B N615 and NR2B N616, these residues are known to form the narrowest region of the channel and the binding site of Mg(2+). However, mutations at NR1 N650, located in the vestibule of channel pore, and NR1 D669, located in the extracellular region, reduced the inhibition by CPCn, suggesting that these amino acid residues interact with CPCn. These results suggest that CPCn interacts directly with the mouth or vestibule of the ion channel, like a lid.

Analytical investigation of two-step adsorption kinetics on surfaces.

Analytical equations of two-step adsorption kinetics on surface have been derived. Moreover, computer simulations have been carried out to interpret various experimental adsorption kinetics previously reported. In the first case, molecules are further adsorbed from a solution onto a layer consisting of previously adsorbed molecules. This model was applied to the adsorption kinetics of hexadecyltrimethylammonium chloride (C16TAC) on a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (T. Imae, H. Torii, J. Phys. Chem. B 104 (2000) 9218). The second case is that some of the initially adsorbed molecules are released from the adlayer with further time course. The adsorption of C16TAC on 1-dodecanethiol SAM (T. Imae, T. Takeshita, K. Yahagi, Stud. Surf. Sci. Catal. 132 (2001) 477) agrees with this mechanism. The strict mathematical developments presented in this work are demanded to specify the physical meaning of observed non-Langmuir adsorption kinetics, consisting of the two exponential terms.