Electrochemical typing of blood using affinity membranes

Human blood group substance of the ABO system was immobilized in a mebrane matrix. The membrane-bound blood group substance retained its binding ability against the corresponding antibody (agglutinin) in serum. The transmembrane potential changed drastically with the agglutination of the membrane-bound blood group substance. Electrochemical typing of blood was performed with sera, using a pair of membranes with immobilized A- and B-type blood group substances. The blood type was determined by measuring the transmembrane potential across these membranes before and after the agglutination reaction. A possible re-use of the membrane-bound blood group substance by treatment with galactose is discussed.     

Statistical Thermodynamics Unveils How Ions Influence an Aqueous Diels-Alder Reaction

The kinetics of Diels-Alder (DA) reactions in water has been known to be altered by salts for a long time. Yet the question how salts influence the reaction rate, either as rate-enhancing or rate-reducing additives, has so far remained unresolved. Conflicting hypotheses involve (i) indirect salt contributions through the modulation of internal pressure and (ii) making (or breaking) of the so-called “water-structure” by salts that strengthen (or weaken) the hydrophobic effect. In contrast to the qualitative nature of these hypotheses, here we answer this question quantitatively through a combination of transition state theory and fluctuation adsorption-solvation theory (FAST) using the DA reaction between anthracene-9-carbinol and N-ethylmaleimide as an example. We show that rate enhancement is driven by the salting out of the hydrophobic reactant, while rate-enhancing salts exhibit stronger affinity to the transition state.     

Supplementary Observations on the Chemistry of the Alkaloids of Berberine Series. II. The Ultraviolet Absorption Spectra of Berberines and Related Compounds

The ultraviolet absorption spectra of berbines and ?-berbines consist of a single, weak and narrow band in which λ_max position dependeds on the kind of auxochrome group i. e., methylenedioxy-or dimethoxy group attached to 2–3 position. The effect of the auxochrome group at 11–12 position or 12–13 position is very small. The shape of the band of oxyberberine, oxy-?-berberine and oxyprotoberberine are similar, especially those of the latter two substances resemble closely. Comparing with isoquinoline, the bands (b), (c) and (d) of G-berberines and protoberberine are considered as characteristic of isoquinoline structure, while the band (a) in visible region is of berberinium structure, however, the absorption curve of ?-berberines does not show any characteristic of isoquinoline or berberinium structure.     

Crystal engineering for topochemical polymerization of muconic esters using halogen-halogen and CH/pi interactions as weak intermolecular interactions

We now report the molecular and crystal structure design of muconic ester derivatives on the basis of crystal engineering using halogen-halogen contacts and CH/pi interactions. The solid-state photoreaction pathway of the dibenzyl (Z,Z)-muconates as the 1,3-diene dicarboxylic acid monomers depends on the structure of the ester groups. The substitution of a halogen atom for the aromatic hydrogen of a benzyl group induces topochemical polymerization to produce stereoregular polymers in a crystalline form, whereas the unsubstituted benzyl derivative isomerizes to yield the corresponding E,E isomer under similar conditions. The topochemical polymerization process is directly confirmed by the fact that the single-crystal structures before and after the polymerization are very similar to each other. From the crystal structure analysis for a series of substituted benzyl (Z,Z)- and (E,E)-muconates, it has been revealed that the planar diene moieties are closely packed to form a columnar structure in the crystals. The stacking of the polymerizable monomers is characterized by a stacking distance of 4.9-5.2 A along the columns. This structure is supported by a halogen-halogen interaction between the chlorine or bromine atoms introduced at the p position of the benzyl groups in addition to an aromatic stacking due to the CH/pi interaction between the benzylic methylene hydrogens and aromatic rings. The design of a monomer packing corresponds to the type and position of the introduced halogen atom and also the polymorphs. To make a stacking distance of 5 A using both halogen-halogen and CH/pi interactions as supramolecular synthons is important for the molecular design of muconic ester derivatives appropriate for topochemical polymerization.     

Distortions of videofiberoscopy imaging: Reconsideration and correction

An analysis was made of the optical distortion of a lens system of a fiberscope and the distortion related to lens-object angles and lens-object distances used in laryngeal flexible endoscopic examinations. The optical distortion was systematic and, therefore, could be corrected through computer processing once the calibration was made. Similarly, the distortion related to the lens-object angle and distance varied systematically depending on distance and angle and, therefore, could be predicted if those parameters were measured simultaneously. The correction of those distortions of videofiberoscopic image is demonstrated, and a procedure for recording and measuring laryngeal images that minimizes measurement error due to those distortions is suggested.     

Development of a simultaneous measurement system of x‐ray diffraction and raman spectra: Application to structural study of crystalline‐phase transitions of chain molecules

The development of a bench‐top‐type system for simultaneous measurement of X‐ray diffraction and Raman spectra has been made to investigate structural changes in the phase transitions of chain molecules such as polyethylene, n‐alkane, and so forth from various viewpoints. For the X‐ray diffraction measurement an imaging plate or a charge‐coupled device camera was used as a two‐dimensional detector. For the Raman spectral measurement a miniature Raman spectrometer was used with optical fibers for the irradiation of incident laser beams and collection of scattered signals. For example, in the heating process of the n‐C₃₀H₆₂ sample, the phase transition from orthorhombic‐to‐hexagonal lattices could be detected clearly by the X‐ray and Raman measurements. By comparing these two different types of data in detail, an intimate relationship between conformational disordering and rotational motion of molecular chains is detected more clearly than before. Also, similar discussion can be made for the orthorhombic‐to‐hexagonal phase transition of the geometrically constrained polyethylene sample occurring immediately below the melting point. Another example concerns the structural change in the photoinduced solid‐state polymerization of cis,cis‐diethylmuconate single crystal. From the shifts in the X‐ray reflection position and Raman frequency characteristic of the produced polymer, it was found that the molecular deformation of the polymer chains and lattice strain was induced in the early stage of the polymerization reaction. For the ferroelectric‐phase transition of vinylidene fluoride copolymer, the simultaneous measurement was made for collecting triple information of small‐angle and wide‐angle X‐ray scatterings and Raman spectra to know the relationship between the structural change in the crystal lattice and the morphological change in the lamellar stacking mode. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 495–506, 2002; DOI 10.1002/polb.10112     

Analysis of methamphetamine and its metabolites in hair

Methamphetamine (MA) is a sympathomimetic amine whose abuse has become a serious problem in Japan, Korea, Taiwan and other Southeast Asian countries. The use of hair for the determination of MA use has become more commonplace. The maximum period in which MA and its main metabolites (amphetamine and p-hydroxymethamphetamine) can be detected in urine is about 10 days after its use. However, proof of MA use is possible in hair even several years after its use if the part of the hair that grew in the period of its use is available. In addition, segmental analysis of hair is capable of clarifying the history of MA abuse. This paper reviews the clean-up, extraction, analytical method and distribution of MA and its metabolites in hair from reports published in the last 20 years.     

Temperature dependence of three-body hydrophobic interactions: potential of mean force, enthalpy, entropy, heat capacity, and nonadditivity

Temperature-dependent three-body hydrophobic interactions are investigated by extensive constant-pressure simulations of methane-like nonpolar solutes in TIP4P model water at six temperatures. A multiple-body hydrophobic interaction is considered to be (i) additive, (ii) cooperative, or (iii) anti-cooperative if its potential of mean force (PMF) is (i) equal to, (ii) smaller than, or (iii) larger than the corresponding pairwise sum of two-methane PMFs. We found that three-methane hydrophobic interactions at the desolvation barrier are anti-cooperative at low to intermediate T, and vary from essentially additive to slightly cooperative at high T. Interactions at the contact minimum are slightly anti-cooperative over a wider temperature range. Enthalpy, entropy, and heat capacity are estimated from the computed PMFs. Contrary to the common expectation that burial of solvent-accessible nonpolar surface area always leads to a decrease in heat capacity, the present results show that the change in heat capacity upon three-methane association is significantly positive at the desolvation barrier and slightly positive at the contact minimum. This suggests that the heat capacity signature of a hydrophobic polymer need not vary uniformly nor monotonically with conformational compactness. Ramifications for protein folding are discussed.     

Growth of high-quality ZnO single crystals by seeded CVT using the newly designed ampoule

The high-quality ZnO single crystals were grown by seeded chemical vapor transport (CVT) in a newly designed ampoule using carbon as a transport agent. The well-faceted crystal of about 5×5×5 mm³ can be grown reproducibly. Secondary ion mass spectroscopy (SIMS) analysis, X-ray rocking curve (XRC) and photoluminescence (PL) measurements demonstrate that the grown single crystal is of high purity and high crystallinity.