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Abstract: A new effect, called attenuated quantum confinement, is described using a theoretical approach, based on the effective mass approximation. It assumes that the exciton, generated in a semiconductor nanocrystal, can penetrate the medium outside the crystal boundary. An equation is derived for the energy of attenuated quantum confinement depending on the penetration depth and mass of exciton outside the crystalline core. It gives lower absorption energy, which is observed experimentally for very small nanocrystals, compared to that predicted by usual quantum confinement. The penetration depth calculated for compound semiconductors is found to be of the same magnitude as that of the thickness of organic capping layer for CdS, CdSe, PbS and InAs nanoparticles. Our finding can also explain other practical processes of charge generation and transportation in a matrix with embedded nanocrystals.

Plant genomes contain a heavily methylated region in which cytosines are methylated in both the symmetrical and asymmetrical sequences. The physical mapping of such a hypermethylated region is difficult because many restriction enzymes are sensitive to methylated cytosine residues in their recognition sites. The Phi29 DNA polymerase provides an efficient and representative amplification of the genomic DNA that is methylation-free. Using this amplified genomic DNA, we were able to show that a heavily methylated genomic DNA region becomes amenable to physical mapping with any restriction enzymes. This protocol will be especially useful for analysis of the heavily methylated region of plant genomes.Plant genomes contain a heavily methylated region in which cytosines are methylated in both the symmetrical and asymmetrical sequences. The physical mapping of such a hypermethylated region is difficult because many restriction enzymes are sensitive to methylated cytosine residues in their recognition sites. The Phi29 DNA polymerase provides an efficient and representative amplification of the genomic DNA that is methylation-free. Using this amplified genomic DNA, we were able to show that a heavily methylated genomic DNA region becomes amenable to physical mapping with any restriction enzymes. This protocol will be especially useful for analysis of the heavily methylated region of plant genomes.

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This paper deals with the structural changes of spherical aggregates composed of elemental gold nanoparticles, called spheroids. The spheroid diameter is reduced to almost 70% of the original diameter by maintaining the spheroid suspension at a constant temperature ranging from 65 to 91 °C for 2−12 h (from 2 h at 91 °C to 12 h at 65 °C). The size-reduced spheroids become monolithic colloids of similar size at each temperature by the end of the reduction process. This is due to an irreversible transition, resulting from fusion among the nanocolloids in spheroids:  coagulative transition. The 30% reduction of the diameter implies that one spheroid is initially composed of 67 nanocolloids at 0.26 volume fraction of the nanocolloids. Assuming that one spheroid gives one monolithic colloid (one-to-one coagulative transition), the lifetime of spheroids can be estimated from the dependence of the transition time on the suspension temperature, for example, 1 month at 22 °C and 6 months at 4 °C. A nonequilibrium thermodynamic model of the spheroid suspension describes the coagulative transition, suggesting that the exclusion and osmotic pressures against intercalated molecules in spheroids are additional factors keeping spheroids in water.

Although the triple-helical structure of fibrillar collagen is regarded in general as being quite similar, each type of collagen molecule has inherent characteristics in the triple-helical domain. Few studies have ever been performed in terms of the aggregate structure of the triple-helical domain of fibrillar collagen. Reconstituted aggregates from the purified triple-helical domain of each type of fibrillar collagen might amplify the subtle differences in the structural characteristics of each type of collagen molecule. In this study, the reconstituted aggregate structure of pepsin-treated type V collagen (type Vp collagen), that is, virtually its triple-helical domain was characterized by transmission electron microscopy. Pepsin-treated type I (type Ip) and type II (type IIp) collagen were compared with type Vp collagen. Unique features of the aggregate structure of the triple-helical domain of the type V collagen can be summarized as follows:1.Type Vp collagen formed fibrils with the D-periodic banding pattern. The banded type Vp fibrils appeared to be of a loosely twisted ribbon-like structure. The average thickness of type Vp collagen fibrils with the banding pattern was significantly smaller than those reconstituted from types Ip and IIp collagen.2.The width of the type Vp collagen fibrils was not affected under the conditions where the D-periodic banded fibrils were formed; the conditions being incubation temperature, protein concentration, and NaCl concentration.3.Type Vp collagen fibrils had little branching and merging. Furthermore, the type Vp collagen fibrils did not bind to each other. On the contrary, type Ip collagen fibrils were often bound to each other and had many branching and merging.

Elemental gold nanocolloids were synthesized by reducing an aurate aqueous solution in the presence of sodium mercaptoacetate. The nanocolloids, 4.6 nm in diameter, self-assembled in highly monodispersed spherical aggregates, 30 nm in diameter, when the nanocolloid suspension was dialyzed in water. Elimination of excess ions, due to dialysis, caused the three-dimensional self-assembly of the nanocolloids. The spheroid and also the elemental nanocolloids before dialysis did not produce the plasmonic absorption peak that is characteristic of conventional gold colloids. Chemisorption of mercaptoacetate onto the nanocolloids caused the peak to disappear. The features of the spheroid structure and assembly mechanism are presented.

The influence of associated viral hepatitis status on 119 patients with primary hepatocellular carcinoma (HCC) undergoing hepatic resection was investigated. Operative morbidity and mortality were examined in three patient groups: 31 patients (group B) positive for hepatitis B surface antigen (HBsAg), 14 (group Be) positive for both HBsAg and hepatitis B e antigen, and 74 (group C) positive for hepatitis C virus antibody (HCVAb). Preoperative liver function in groups Be and C was similar and more impaired than that of patients in group B; combined active hepatitis was seen most frequently in group C (68 per cent). The tumour size in group B was significantly greater than that in groups Be and C. Postoperative complications occurred more frequently in group C (39 per cent) and early postoperative deaths, other than those from cancer, were seen in nine patients positive for HCVAb, of whom three developed postoperative liver failure. Patients with HCC and hepatitis B without seroconversion as well as hepatitis C frequently have active hepatitis, which may impair liver function and play an important role in operative morbidity and mortality.

In order to clarify the factors contributing to the signal intensities (SIs) of HCC on T1-weighted images, the amount of water, lipid, copper (Cu), iron (Fe), and manganese (Mn) was determined in HCC and surrounding hepatic parenchyma of 13 patients. The relationships among these findings, the histopathologic findings, and the SIs of T1-weighted images were evaluated.Among the 13 HCC, 3 had a high SI, 5 were isointense, and 5 had a low SI on T1-weighted images compared to the surrounding hepatic parenchyma. The paramagnetic ions which contributed to the SI patterns were assumed to be Cu in HCC (38.0±62.4 μg/g ww), and Fe in the liver (61.1±42.4 μg/g ww) and HCC (40.0±34.3 μg/g ww). In 8 HCC with high- or isointensity, 2 were grades I, 5 were grade II, and one was grade III according to the Edmondson-Steiner's histopathologic classification. It is concluded that the SI patterns alone can not be a sign of low grade malignancy because of the existence of Fe in livers and HCC.

In order to clarify the factors contributing to the signal intensities (SIs) of HCC on T1-weighted images, the amount of water, lipid, copper (Cu), iron (Fe), and manganese (Mn) was determined in HCC and surrounding hepatic parenchyma of 13 patients. The relationships among these findings, the histopathologic findings, and the SIs of T1-weighted images were evaluated.Among the 13 HCC, 3 had a high SI, 5 were isointense, and 5 had a low SI on T1-weighted images compared to the surrounding hepatic parenchyma. The paramagnetic ions which contributed to the SI patterns were assumed to be Cu in HCC (38.0±62.4 μgg ww), and Fe in the liver (61.1±42.4 μgg ww) and HCC (40.0±34.3 μgg ww). In 8 HCC with high- or isointensity, 2 were grades I, 5 were grade II, and one was grade III according to the Edmondson-Steiner's histopathologic classification. It is concluded that the SI patterns alone can not be a sign of low grade malignancy because of the existence of Fe in livers and HCC.

Localizations of collagen types I, III, and V in monkey liver, as determined by the indirect immunofluorescence method, were photographically superimposed on the fibers revealed by silver-staining in the same tissue sections. Immunofluorescence for type I collagen was found to correspond with the brown collagen fibers and with some of the coarse reticular fibers, while that for type III collagen was found to correspond with most, but not all, reticular fibers of the liver as well as with the brown collagen fibers. The distribution of type V collagen coincides not only with the collagen fibers in the stroma of portal triads and around the central veins, but also with the coarse and fine reticular fibers in the liver lobules. By immuno-electron microscopy, reaction products with anti-type III and V collagens antibodies were demonstrated on cross-striated collagen fibrils, about 45 nm in diameter, in the space of Disse. From these observations, it is concluded that: (1) the fine reticular fibers are mainly composed of type III and type V collagens, and (2) the collagen fibers and coarse reticular fibers in the periphery of liver lobules are composed of type I, type III and type V collagens.

Pattern evoked potentials were recorded simultaneously with an electrode placed on the skin of the lower eyelid, gold foil electrodes hooked on the right and left eyelids, and a skin electrode at Oz in normal subjects and in patients with optic nerve and macular diseases. Peak latencies and amplitudes of the pattern electroretinogram (PERG) were compared between the two electrodes.

Visually evoked cortical potentials in response to pattern-appearance, disappearance, and -reversal stimuli were studied in normal subjects and in patients suffering from optic neuritis. It was found in normal subjects that pattern disappearance VECPs were as reliable as the pattern reversal ones. On the other hand, the appearance response showed interindividual differences which made its evaluation rather difficult. The same was true in the records of the patients. Both the mean peak latencies of the disappearance responses and those of the pattern reversal ones were prolonged significantly in optic neuritis, compared with those obtained from normal subjects. We concluded that the peak latencies of the disappearance response could be more confidently used than those of the appearance response for diagnosing optic neuritis.

Hexagonally packed holoferritin arrays were produced on a silicon wafer by mechanically expanding (using a scratching method) the holoferritin solution to form a wetting film on the surface. This film is then dried, during which the protein array forms. The packing state of holoferritin depended on the surface charge of the molecules in the wetting film and on the drying rate of the film (i.e., evaporation rate of the water from the film). We found that a secondary minimum was created and then annihilated near the air/water interface and had a potential profile during the evaporation of the water from the wetting film. Consequently, we introduced a concept called the lifetime of a secondary minimum. Since this minimum formed in two-dimensions in the wetting film (primary film), we called it a secondary film in contrast to the primary film that was primarily created in two-dimensions. Such a secondary film can provide a two-dimensional container for nanometer-sized particles, such as proteins, and bring about an Alder-type transition. This new formation technique has widespread application in industry, such as mass production of high-sensitivity bio-sensors.

Type IX collagen, containing molecules of the three distinct polypeptides alpha 1(IX), alpha 2(IX), and alpha 3(IX), is an interesting hybrid extracellular matrix component in cartilage and eye tissues, with the properties of both a proteoglycan and a collagen. The alpha 1 (IX) chain has two forms, as a result of the tissue-specific utilization of two alternative promoters; the alpha 2(IX) chain carries a covalently attached glycosaminoglycan side chain. We have introduced a gene construct controlled by a tissue-specific promoter/enhancer and expressing a truncated alpha 1(IX) chain into mice. Examination of the offspring of two different founders revealed pathological changes similar to osteoarthritis in the articular cartilage of knee joints. In addition, mice homozygous for the transgene developed mild chondrodysplasia (i.e., mild dwarfism, anterior tonguing in the vertebral bodies, and ophthalmopathy). The relative ratio of transgene product to the endogenous alpha 1(IX) chain was approximately one in homozygotes and less than one in heterozygotes. Therefore, the phenotypic severity correlated well with the level of transgene expression. These findings suggest that mutations in type IX collagen genes may cause certain forms of osteoarthritis and chondrodysplasia in humans.

We have screened genes predominantly expressed in the rat spinal cord, and we report here cloning of the most abundant unknown gene. It is a novel member of the central nervous system (CNS) myelin-constituting proteins, myelin-associated oligodendrocytic basic protein (MOBP). MOBP is abundantly expressed specifically in oligodendrocytes at the mRNA level only next to myelin basic protein (MBP) and proteolipid protein. Two isoforms have been confirmed. One of them has proline-rich tandem repeats and has 84& homology with human counterpart in terms of predicted amino acid sequences. The cDNA-derived primary structure predicts a small, soluble, basic protein. The immunoelectron microscopy has shown that MOBP is expressed throughout compact myelin. All these characteristics are similar to MBP. One definite difference between MBP and MOBP is that MOBP is expressed exclusively in the CNS myelin. These findings suggest that MOBP shares some important functions with MBP in the CNS myelin such as myelin compaction.

To determine the optimal surgical therapy for patients with pedunculated hepatocellular carcinoma (HC), we evaluated findings in ten patients with pedunculated HC among 350 patients with HC who underwent hepatectomy from 1975 to 1991 at Kyushu University Hospital. These patients were classified into three groups: Group I (n = 4) Pedunculated HC with no intrahepatic HC, Group II (n = 2) Pedunculated HC with a single intrahepatic HC, and Group III (n = 4) Pedunculated HC with multiple intrahepatic HC. Patients in group I and II were treated by partial hepatic resections or subsegmentectomies. In two patients there was an intrahepatic recurrence in the same lobe, after radical resection. All patients in group III who underwent palliative resection died within 8 months after surgery. Retrospectively, we favour the view that patients in Groups I or II may have had a better prognosis if lobectomy rather than partial hepatectomies had been done.

Previous observations suggested that incubating fibroblasts at elevated temperature caused over-modification of type I procollagen by post-translational enzymes because of a delay in folding of the collagen triple helix. Here, human skin fibroblasts were incubated at 40.5 instead of 37 degrees C, and the type I procollagen secreted into the medium was isolated. Analysis of the protein indicated that there was an increase of about 5 residues of hydroxylysine/alpha chain and about 1 residue of glycosylated hydroxylysine/alpha chain. Assays with procollagen N-proteinase indicated that the N-propeptide of the over-modified collagen was cleaved at a decreased rate, apparently because the over-modification altered the conformation-dependent cleavage site for the enzyme. Assays in a system for assembly of collagen into fibrils demonstrated that the over-modified protein had a higher critical concentration for self-assembly. Also, the fibrils formed from the over-modified collagen at 31 and 29 degrees C had smaller diameters than fibrils formed from normal type I collagen. The results provide direct evidence for earlier suggestions that post-translational over-modification of a fibrillar collagen can alter the morphology of the fibrils formed. The results also indicate that some of the biological consequences of the mutations in type I procollagen causing heritable disorders must be ascribed to the effects of post-translational over-modifications that frequently occur as secondary consequences of changes in the primary structure of the protein.

It is demonstrated that thermal annealing of RF plasma CVD silicon films below 600 °C increases the crystalline component of the film.