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Mixed Langmuir−Blodgett (LB) films of 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (C18TCNQ) and deuterated stearic acid (stearic acid-d35) were fabricated to investigate effects of incorporation of the fatty acid on molecular orientation and structure in LB films of C18TCNQ. A π−A isotherm of the mixed Langmuir film suggests that C18TCNQ and stearic acid-d35 are segregated in the film and that above 22 mNm^-1 the C18TCNQ domains start to collapse or the C18TCNQ molecules are squeezed out from the fatty acid monolayer on the water subphase. Ultraviolet−visible and infrared transmission and reflection−absorption (RA) spectra were measured for one-, three-, and five-layer mixed LB films deposited at 18 and 35 mNm^-1. A doublet peak caused by the CH2 scissoring mode of the alkyl chain of C18TCNQ suggests that the phase separation occurs in the mixed LB films. Infrared spectra of LB films of C18TCNQ alone give two bands at 2926 and 2918 cm^-1 due to the CH2 antisymmetric stretching modes of the partially disordered and highly ordered parts of the alkyl chain of C18TCNQ, respectively. In the corresponding spectra of the mixed LB films, the band at 2926 cm^-1 becomes very weak. Thus, the percentage of the partially disordered part is reduced markedly by mixing C18TCNQ with fatty acid. Molecular orientation of C18TCNQ is also changed significantly upon the formation of the mixed LB films. For example, the alkyl chain becomes more perpendicular, whereas the TCNQ plane becomes more parallel to the substrate surface. The reduction in the ratio of the partially disordered part of the alkyl chain and the change in the molecular orientation of C18TCNQ in the mixed LB films are probably due to freezing-in effects of the fatty acid domains which block the realignment of C18TCNQ during the film deposition. The infrared spectra of the mixed LB films deposited at 35 mNm^-1 show that the molecular orientation and structure of C18TCNQ change greatly because of the collapse of the C18TCNQ layer at this pressure.

Time-dependent changes in molecular orientation, structure, and morphology in one-layer Langmuir−Blodgett (LB) films of 2-dodecyl-, 2-pentadecyl-, and 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (dodecyl-TCNQ, pentadecyl-TCNQ, and octadecyl-TCNQ) have been investigated by means of infrared and ultraviolet and visible (UV−vis) spectroscopy and atomic force microscopy (AFM). The intensities of bands at 2920 and 2850 cm^-1 due to CH2 antisymmetric and symmetric stretching modes of the alkyl chain and those of bands at 2222, 1547, and 1529 cm^-1 assigned to C&tbd1;N, C&dbd;C, and C&dbd;C stretching modes of the TCNQ chromophore increase significantly with time in the infrared reflection−absorption (RA) spectrum of a one-layer LB film of pentadecyl-TCNQ after the film deposition on a gold-evaporated glass slide. These observations indicate that the alkyl chain becomes more tilted with respect to the surface normal during the time course and the TCNQ plane becomes more perpendicular with respect to the substrate surface. The time-dependent changes are also observed for one-layer LB films of dodecyl-TCNQ, but the changes are much smaller than those for the films of pentadecyl-TCNQ. One-layer LB films of octadecyl-TCNQ do not show appreciable infrared spectral changes with time. A UV−vis spectrum in the 350−450 nm region of the one-layer LB film of pentadecyl-TCNQ on a CaF2 plate consists of two bands due to the stacked and aggregation forms of the TCNQ chromophore. As a function of time, the intensity of the band due to the aggregation form increases while that of the band due to the stacked form decreases, indicating that some of the stacked TCNQ chromophores change into the aggregation with the change in the molecular orientation. The increase in baseline is also noted in the UV−vis spectrum. The baseline change may be due to the partition of the large domains of the one-layer film into small domains with the size of ~1 μm. Time-dependent measurements of the AFM image of a one-layer LB film of pentadecyl-TCNQ on mica have revealed that the thickness of the film changes from 4.6 to 8.2 nm and that the flat and uniformed structure of the film changes into the condensed and accumulated structure during the time course from 15 to 180 min after the film deposition. Aged one-layer LB films of dodecyl- and octadecyl-TCNQ are similar to the aged and fresh one-layer LB films of pentadecyl-TCNQ, respectively, in terms of both the film morphology and thickness. On the basis of the results of infrared and UV−vis spectroscopy and AFM, we propose a model for the time-dependent morphological and structural changes in the one-layer LB films of the alkyl-TCNQ. The differences in the aging effects among the one-layer LB films of the three kinds of alkyl-TCNQ may be concerned with the differences in the strength of the hydrophobic interaction between the interdigitated alkyl chains and in the degree of three-dimensional microcrystal growth of the one-layer LB films.

Reversible “cold cataract” phenomenon of a SD-strain rat lens (29 days old) was studied by Raman spectroscopy in the temperature range of 35–17.5°C. Cold cataract appeared in the lens nucleus below 26°C. The Raman spectra did not show any detectable change in the 300–800 cm−1and 900–4000 cm−1regions as the temperature decreased. However lens opacification caused a significant change in the intensity ratio of tyrosine doublet near 840 cm−1, suggesting that some tyrosine residues in lens proteins undergo a change in their hydrogen bonding environment during the cold cataract formation. It was also found that the intensity ratio of the tyrosine doublet band provides a practical indicator of phase transition temperature of cold cataract.

Background. Hepatocyte growth factor (HGF) plays a key role in the regulation of liver regeneration after hepatocyte damage. Changes in HGF production reflect the status of the, regeneration process. Methods. Serum concentrations of HGF and energy substrates were measured during and after liver transplantation in 30 recipients. Results. In the patients with compromised grafts (group A) HGF concentrations were persistently high after reperfusion, whereas in the patients with well-functioning grafts (group B), HGF concentrations decreased rapidly and remained low 4 hours after reperfusion. The patients in group A who died had persistently high concentrations of HGF. The surviving patients with reversible primary graft dysfunction in group A exhibited low concentrations 48 hours after reperfusion. The decrease in HGF concentration preceded the decrease in aspartate aminotransferase concentration. The metabolic parameters that reflect carbohydrate metabolism by the graft paralleled the changes in HGF. Conclusions. HGF may be more sensitive and specific in predicting early graft function than prothrombin time ratio, aspartate aminotransferase, or arterial ketone body ratio. The determination of HGF levels after liver transplantation may yield valuable information for evaluating early graft function and making an early decision to repeat a graft procedure in an acutely ill patient.

Infrared spectra of one-monolayer Langmuir-Blodgett (LB) films of chlorophyll-a(Chl-a) can be obtained with a high signal-to-noise ratio by using the attenuated total reflection (ATR) technique. The observed spectra indicate that Chl-aassumes a five-coordinated monomer in the LB films; it seems that both the ester and keto C=O groups are free from any interactions, and a water molecule coordinates to the Mg atom. Comparison of the spectra of the one-monolayer LB films with those of the cast films shows that the structure of Chl-ais quite different between the two kinds of films; in contrast to the LB films the cast films are liable to have the dimer or oligomer of Chl-a. The fact that the five-coordinated monomer is predominant in the LB films suggests that Chl-amolecules are highly oriented in the one-monolayer LB films.

FT-IR spectra were measured in situfor an albino rabbit lens capsule by use of the ATR method, and the spectrum of water was subtracted. The obtained difference spectra resemble the spectrum of purified Type IV collagen in aqueous solution and show intense bands at 1637 and 1553 cm−1assignable to the amide I and II modes, respectively. These frequencies are very close to those of the amide I and II bands of a 31helix. This is direct evidence for the existence of the so-called collagen helix (a slightly modified 31helix) in the lens capsule. FT-IR spectra were also measured by the diffuse reflectance method for the dried capsule stripped from a dried lens. IR frequencies of the amide I and II bands of the capsule collagen shift from 1637 and 1553 cm−1to 1654 and 1540 cm−1, respectively, upon going from the intact capsule to the dried one, showing that the collagen helix is converted to a random coil structure upon drying.

Molecular aggregation and orientation in mixed Langmuir−Blodgett (LB) films of 5-(4-N-octadecylpyridyl)-10,15,20-tri-p-tolylporphyrin (porphyrin 338a) and stearic acid have been investigated by means of ultraviolet−visible (UV−vis), fluorescence, and infrared (IR) spectroscopies. It has been found that for the multilayer mixed LB films deposited onto glass and gold-evaporated glass substrates, the formation of porphyrin aggregates is facilitated by adding stearic acid, evidenced by a 3−6 nm red shift of the Soret band in the UV−vis spectra and a 5 nm red shift of the Q(x)(0,0) band in the fluorescence emission spectra, compared to the corresponding LB films of porphyrin 338a. This result and that for the one-layer mixed films suggest that fatty acid molecules impose their effect on promoting the porphyrin aggregation in the mixed films via interlayer interactions. Comparison of IR spectra between the mixed films and those of porphyrin 338a leads to the conclusion that the alkyl chains of porphyrin 338a molecules in the mixed LB films become ordered and closely packed and more perpendicular to the substrate surface compared to those in the LB films of porphyrin 338a. The comparison of ratio of intensities of CH2 antisymmetric and C&dbd;N (pyridyl group) stretching bands in the IR spectra between mixed LB films and the LB films of porphyrin 338a also supports this conclusion.

Several kinds of recently advanced microanalytical techniques—like electron probe x-ray microanalysis, laser Raman microprobe, and Fourier transform-infrared spectroscopy combined with a microsampling method—have been used for the study of the microstructure of gallstones. The organic and inorganic constituents of three kinds of gallstones are characterized on a microscopic scale. The microstructure of a cholesterol-bilirubin gallstone with a layered structure has been studied with particular emphasis. Small white particles contained in both a bilirubin gallstone and a cholesterol-bilirubin mixed gallstone have been found to consist of calcium salt of a fatty acid, probably calcium palmitate. The results obtained here will be very useful for understanding the mechanism of the gallstone-formation process.

Morphology and annealing effects of mixed-stack charge transfer (CT) complex films of 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (octadecyl-TCNQ) doped by 5,10-dimethyl-5,10-dihydrophenazine ((Me)2P) have been investigated by atomic force microscopy (AFM) and ultraviolet−visible−near-infrared (UV−vis−NIR) and infrared (IR) spectroscopies. The AFM measurements scanned at room temperature show that the 11-layer CT film consists of layered platelet microcrystal domains with a layer distance of 3.3 nm, which is in good agreement with the distance obtained by an X-ray diffraction experiment. It is likely that each layer in the CT film has a bimolecular layer structure as in the case of Langmuir−Blodgett (LB) films of neutral octadecyl-TCNQ. A two-dimensionally resolved molecular arrangement of octadecyl-TCNQ and (Me)2P is observed inside the domains by a high-resolution AFM image. The inter- and intrastack periods, which are across and along the CT stacks, are 0.96 and 0.83 nm, respectively, with an intersect angle of 59°. A cyclic thermal treatment on the CT film up to 70 °C, which is below the dedope temperature, does not change its morphology, i.e., the molecular arrangement and layered structure in the microcrystal domains are nearly unchanged. However, when the CT film is heated above the dedope temperature, the layered structure vanishes completely and the molecular arrangement becomes similar to that in the LB film of neutral octadecyl-TCNQ. The UV−vis−NIR and IR spectra of the annealed CT films confirm the results obtained by AFM.

Molecular orientation and structure in mixed-stack charge transfer (CT) films of 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (octadecyl-TCNQ) doped by 5,10-dimethyl-5,10-dihydrophenazine ((Me)2P) have been investigated by using ultraviolet−visible−near-infrared (UV−vis−NIR) and infrared (IR) spectroscopies and X-ray diffraction. The degree of charge transfer (ρ) was determined to be 0.5 by a shift of a b1u C&tbd1;N stretching band of the TCNQ chromophore, suggesting that the complex is close to the neutral−ionic boundary. An X-ray diffraction pattern indicates that the CT films consist of a highly ordered multilayered structure in which donor ((Me)2P) and acceptor (octadecyl-TCNQ) molecules are periodically arranged. The d value was calculated to be 3.3 nm, implying that each layer of the CT films comprises bimolecular layers. Comparison of IR intensities of b1u, b2u, and ag C&tbd1;N stretching bands of the acceptor (A) and a totally symmetric band at 1255 cm^-1 of the donor (D) between the transmission and reflectance absorption (RA) IR spectra indicates that the chromophores of D and A are almost perpendicular to the substrate surface with their long molecular axes being nearly parallel to the surface normal in the one-layer mixed-stack CT films. The hydrocarbon chain of octadecyl-TCNQ was evaluated to lie on the substrate. In the multilayer CT films the D and A chromophoric planes seem to be slightly tilted with respect to the substrate surface.