Trapping adsorption of carbon monoxide located between carbon dioxide adsorbed on magnesium oxide

Carbon monoxide adsorbed on MgO is strongly trapped by the adsorbed carbon dioxide, increasing the heat of adsorption from 85.4 to 184.1 kJ/mol. The trapped CO is thought to be captured by two or three adsorbed CO₂ and becomes less active to react with oxygen.

---

, MgO, , 85,4 184,1 /. , CO CO₂ .

     

Raman spectral changes of alcoholic zinc chloride solutions from liquid state to glassy state

Raman spectral changes associated with vitrification were measured for ZnCl₂·4OROH solutions (ROH=methanol, ethanol and 1-propanol). Solvated ZnCl₂ is the only major Zn-species in these solutions at room temperature while the dominant Zn-species stabilized in the glassy alcoholic solutions are ZnCl ₃ ^– , ZnCl ₄ ^2– and [Zn(MeOH)₆]²⁺ for the methanol solution, ZnCl₂ and ZnCl ₃ ^– for the ethanol solution and ZnCl₂ for the 1-propanol solution. Together with Raman data for aqueous ZnCl₂ solutions, the differences in the dominant Zn-species in the glassy alcoholic solutions are discussed in terms of the dielectric constants of solvents (water and alcohols).     

Effects of the photooxidant on DNA-mediated charge transport

A direct comparison of DNA charge transport (CT) with different photooxidants has been made. Photooxidants tested include the two metallointercalators, Rh(phi)(2)(bpy')(3+) and Ru(phen)(bpy')(dppz)(2+), and three organic intercalators, ethidium (Et), thionine (Th), and anthraquinone (AQ). CT has been examined through a DNA duplex containing an A(6)-tract intervening between two 5'-CGGC-3' sites with each of the photooxidants covalently tethered to one end of the DNA duplex. CT is assayed both through determination of the yield of oxidative guanine damage and, in derivative DNA assemblies, by analysis of the yield of a faster oxidative trapping reaction, ring opening of N(2)-cyclopropylguanine (d(CP)G) within the DNA duplex. We find clear differences in oxidative damage ratios at the distal versus proximal 5'-CGGC-3' sites depending upon the photooxidant employed. Importantly, nondenaturing gel electrophoresis data demonstrate the absence of any DNA aggregation by the DNA-bound intercalators. Hence, differences seen with assemblies containing various photooxidants cannot be attributed to differential aggregation. Comparisons in assemblies using different photooxidants thus reveal characteristics of the photooxidant as well as characteristics of the DNA assembly. In the series examined, the lowest distal/proximal DNA damage ratios are obtained with Ru and AQ, while, for both Rh and Et, high distal/proximal damage ratios are found. The oxidative damage yields vary in the order Ru > AQ > Rh > Et, and photooxidants that produce higher distal/proximal damage ratios have lower yields. While no oxidative DNA damage is detected using thionine as a photooxidant, oxidation is evident using the faster cyclopropylguanosine trap; here, a complex distance dependence is found. Differences observed among photooxidants as well as the complex distance dependence are attributed to differences in rates of back electron transfer (BET). Such differences are important to consider in developing mechanistic models for DNA CT.     

Synthesis and properties of microgel bearing a mercapto group

Vinylbenzyl S-thioacetate ( 1 ) was prepared from thioacetic acid and chloromethylstyrene. Although bulk polymerization of 1 afforded a crosslinked polymer, solution polymerization in chlorobenzene afforded a corresponding soluble polymer. The S-thioacetate group did not react during the radical polymerization of 1 . Bulk copolymerization of 1 with styrene afforded a soluble copolymer when the feed ratio of 1 was lower than 30 mol %. Soap-free emulsion copolymerization of 1 , St, divinylbenzene, and 2-hydroxyethyl methacrylate (66 : 28 : 1 : 5) was carried out in water using 2,2′-azobis (N,N′-dimethyleneisobutyramidine) dichloride as an initiator to afford uniform spherical microgel 2 , whose average diameter was 135 nm. Aminolysis of 2 with an excess amount of butylamine in the presence of sodium tetrahydridoborate followed by treatment with hydrochloric acid resulted in complete removal of the acetyl group to give a slightly distorted spherical microgel (MG-SH) bearing mercapto group. The average diameter of MG-SH was 165 nm. Trans-esterification of p-nitrophenyl acetate ( 3 ) in the presence of triethylamine was efficiently accelerated by the addition of MG-SH. The radical polymerization of methyl methacrylate (MMA) in the presence of suspended MG-SH in chlorobenzene afforded the MMA-grafted microgel. Although MG-SH is a crosslinked gel, it acts as a soluble polymer bearing mercapto group. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1443–1451, 1997     

Octonionic Yang–Mills instanton on quaternionic line bundle of Spin(7) holonomy

The total space of the spinor bundle on the four-dimensional sphere S⁴ is a quaternionic line bundle that admits a metric of Spin(7) holonomy. We consider octonionic Yang–Mills instanton on this eight-dimensional gravitational instanton. This is a higher dimensional generalization of (anti-) self-dual instanton on the Eguchi-Hanson space. We propose an ansatz for Spin(7) Yang–Mills field and derive a system of non-linear ordinary differential equations. The solutions are classified according to the asymptotic behavior at infinity. We give a complete solution when the gauge group is reduced to a product of SU(2) subalgebras in Spin(7). The existence of more general Spin(7) valued solutions can be seen by making an asymptotic expansion.     

Direct determination of non-steroidal anti-inflammatory drugs by column-switching LC-MS

A method for determination of 16 non-steroidal anti-inflammatory drugs (NSAIDs) in human plasma samples without time-consuming sample pre-treatments was developed. The system consisted of two pumps for mobile phase delivery, a six-port switching valve, a pre-column (Oasis HLB Cartridge Column), and a reversed phase analytical column (COSMOSIL 3C18-MS-II). The analytes were trapped on the precolumn and subsequently separated on the analytical column. The present method allowed on-line sample clean-up and enrichment, leading to improved sensitivity without any tedious sample preparation. The recoveries of NSAIDs from human plasma by column-switching were greater than 72.6%. The total analysis time for a single analytical run was approximately 11 min. The detection limits of NSAIDs were 0.0025 to 0.2 microg/mL using the selected ion monitoring mode.     

High-resolution optical storage by use of minute spheres

We have developed a new optical storage system that uses minute spheres arranged upon a surface-relief grating. By using dye-doped minute spheres as recording bits we can limit a sensitive region within a sphere's diameter. Using a reflection-type confocal optical system, we read out shape signals from minute spheres at high resolution. The shape signals from minute spheres are utilized as clock signals in recording and readout.     

Ultrafast walk-off-free nonlinear optical loop mirror by a simplified configuration for 320-Gbit / s time-division multiplexing signal demultiplexing

We demonstrate a simplified configuration of an ultrafast walk-off-free nonlinear optical loop mirror (NOLM) for 320-10-Gbit/s optical time-division demultiplexing. The proposed NOLM consists of a short, 100-m length of highly nonlinear dispersion-shifted fiber, resulting in compact, highly stable, and ultrafast walk-off-free operation.     

Rapid enzymatic transglycosylation and oligosaccharide synthesis in a microchip reactor

Glycosidase-promoted hydrolysis was performed in a microreaction channel. The result was compared with the reaction in a micro-test tube. Transgalactosylation on p-nitrophenyl-2-acetamide-2-deoxy-beta-D-glucopyranoside was also examined in a microreaction channel, because transglycosylation is a useful method for oligosaccharide synthesis. We examined both the forward reaction, i.e., hydrolysis, and the reverse reaction, i.e., transglycosylation, in the microreaction channel. The results showed that both hydrolysis and transglycosylation were enhanced in the microreaction channel compared with the batch reaction.