Spatiotemporal expression of C-CAM in the rat placenta

We investigated the expression of the immunoglobulin superfamily cell adhesion molecule, C-CAM, in developing and mature rat placenta. By immunohistochemical staining at the light microscopic level, no C-CAM-expression was seen before Day 9 of gestation, when it appeared in the trophoblasts of ectoplacental cones. On Day 10.5, spongiotrophoblasts and invasive trophoblasts around the maternal vessels of the decidua basalis were stained positively. On Day 12.5, C-CAM was detected in the spongiotrophoblasts of the junctional layer, but labyrinth trophoblasts and secondary giant trophoblasts were not stained. On Day 17.5, C-CAM was found only in the labyrinth and lacunae of the junctional layer. At this stage, both the labyrinth cytotrophoblasts of the maternal blood vessels and the endothelial cells of the embryonic capillaries were strongly stained. Placental tissues from gestational Days 12.5 and 17.5 were analyzed by immunoelectron microscopy to determine the location of C-CAM at the subcellular level. On Day 12.5, positive staining of the spongiotrophoblasts was observed, mainly on surface membranes and microvilli between loosely associated cells. On Day 17.5, staining was found primarily on the microvilli of the maternal luminal surfaces of the labyrinth cytotrophoblasts, and both on the luminal surface and in the cytoplasm of endothelial cells of the embryonic vessels. RT-PCR analysis and Southern blotting of the PCR products revealed expression of mRNA species for both of the major isoforms, C-CAM1 and C-CAM2. Immunoblotting analysis of C-CAM isolated from 12.5-day and 14.5-day placentae showed that it appeared as a broad band with an apparent molecular mass of 110-170 kD. In summary, C-CAM was strongly expressed in a specific spatiotemporal pattern in trophoblasts actively involved in formation of the placental tissue, suggesting an important role in placental development. In the mature placenta, C-CAM expression was confined to the trophoblastic and endothelial cells lining the maternal and embryonic vessels, respectively, suggesting important functions in placental physiology.     

α-sulfonated fatty acid esters: II. Solution behavior of α-sulfonated fatty acid polyethylene glycol esters

Sodium α-sulfonated, fatty acid polyethylene glycol monoesters [C _m H_2m+1CH(SO₃Na)COO(C₂H₄O) _n H] and diesters [C _m H_2m+1CH(SO₃Na)COO(C₂H₄O) _n COCH(SO₃Na)C _m H_2m+1], wherem=10–16 andn=1–35, were prepared by esterification of α-sulfonated, fatty acids with polyethylene glycols, followed by neutralization with NaOH. Crude products were purified by reversed-phase column chromatography on an octadecyl-modified silica gel. Characteristic solution behavior of these α-sulfonated fatty acid esters was, examined, and the following features were observed. All monoesters prepared in this work had Krafft points below 0°C and also possessed good calcium stabilities. Critical micelle concentrations of the monoesters increased monotonously, as a rule, with an increase in the number of oxyethylene units. These results suggest that the polyethylene glycol residue of the monoester behaves as a hydrophile. On the other hand, diesters possessed high water solubility, low foamability, and critical micelle concentrations that were lower by a factor of ten compared to those of the monoesters.     

Photoexcited states in directly synthesized trans-polyacetylene films studied by photocurrent measurement

A trans-polyacetylene film was directly synthesized to reduce defects introduced during usual thermal isomerization treatment. A photocurrent excitation spectrum of this film showed very low efficiency around a reflection peak which was accompanied with phonon side bands. This strongly indicates that the lowest optically allowed state of trans-polyacetylene is a 1¹B^u exciton state like other conjugated polymers, such as polydiacetylenes. Misinterpretations of the experimental results under the SSH model, because of the use of a film of low quality, are pointed out and reinterpretations are made according to the present conclusion.     

Kobe earthquake and reduced sperm motility

We investigated a possible relationship between the Kobe earthquake (January 17, 1995) and the quality of semen. We assessed sperm concentration and motility of 27 male patients who had a concentration of more than 30 million/ml and >40% sperm motility within 5 months before the earthquake. Twelve male patients from districts with a magnitude of <4 on the Richter scale showed no difference in sperm concentration and motility before and after the earthquake. Of 15 male patients from districts with a magnitude of >6, five patients whose houses received no damage showed no distinct changes in sperm concentration and motility. In contrast, 10 patients whose houses were partially or completely destroyed showed significantly (P < 0.001) lower sperm motility after the earthquake than before, although no significant difference of sperm concentration could be observed. Of these latter 10 patients, seven could be followed. In six patients, sperm motility was restored between 2 and 9 months after the earthquake; the sperm motility in one patient, whose father died a victim of the house crash, has not yet recovered. Thus, the acute stress resulting from such a catastrophic earthquake could be a possible cause of reduced sperm motility.     

Characteristics of mutations in the p53 gene of oral squamous-cell carcinomas associated with betel-quid chewing in Sri Lanka

The PCR copy of the ribR gene of Bacillus subtilis was subcloned in Escherichia coli cells under the control of the phage T7 inducible promoter. The polypeptide of 26 kDa corresponding to the 690-bp gene is the product of the ribR gene. The protein encoded by the ribR gene is flavokinase, and the riboflavin-reduced form is the substrate for it.     

Lead-free soldering in the Japanese electronics industry

Japan has witnessed prosperous industrial growth since the 1960s, and this growth has given rise to increased awareness by the government and the people regarding environmental responsibility. This responsibility includes the use of "green" materials and the recycling of important resources. Legislation, including the appliances law, requires the Japanese electronics industry to comply with more stringent environmental stipulations. However, Japanese electronics companies have captured international attention by preempting legislation with the introduction of lead-free products in the market with an ambitious target of eliminating the use of lead in electronic products. In this paper, we investigate corporate strategies regarding lead-free product development in light of legislative and environmental issues in Japan.     

Surface hydrophilicity and enzymatic hydrolyzability of biodegradable polyesters: 1. effects of alkaline treatment

Surface treatment using alkaline solutions was attempted to enhance the surface hydrophilicity and enzymatic hydrolyzability of hydrophobic poly(L ‐lactide) [ie poly(L ‐lactic acid) (PLLA) and poly(ε‐caprolactone) (PCL). The alkaline treatment was performed by immersing the PLLA and PCL films in 0.01 and 4 N NaOH solutions, respectively, for various periods of time. The effects of the alkaline treatment on the hydrophilicity of the films were monitored by dynamic contact angle measurements, while the enzymatic hydrolyzability of the PLLA and PCL films after the alkaline treatment were evaluated by weight losses in the presence of proteinase K and Rhizopus arrhizus lipase, respectively. With the alkaline treatment the hydrophilicity of the PLLA and PCL films was controllable in the advancing contact angle (θ_a) ranges of 84–108° and of 69–93°, respectively, by varying the alkaline treatment time. The enzymatic hydrolysis rates of the PLLA films became higher with decrease of the θ_a, irrespective of the crystallinity, strongly suggesting that the surface hydrophilicity or the surface molecular weight is crucial to determine their enzymatic hydrolyzability. In contrast, the enzymatic hydrolyzability of the PCL films remained unchanged even when the θ_a decreased from 93° to 73° by alkaline treatment for 4 h. However, prolonged alkaline treatment for periods of time exceeding 4 h, which insignificantly altered the θ_a but caused the formation of pores and cracks on the PCL film surface, accelerated the enzymatic hydrolysis of the PCL films. This indicates that the enzymatic hydrolyzability of the PCL film depends on the surface area per unit weight rather than the surface hydrophilicity. Copyright © 2003 Society of Chemical Industry     

A series‐connected hybrid triple converter system

This paper proposes a hybrid multiconverter system aiming at a large‐capacity high‐voltage high‐efficiency converter system free from harmonics in its input/output. The system consists of n (n: integer) GTO converters and a single neutral‐point‐clamped IGBT converter connected in series by n + 1 output transformers. The GTO converters operate in a square‐wave switching mode while the IGBT converter operates in a PWM switching mode. The former produces a base part of the resultant output voltage. The latter not only produces an additional part of the resultant output voltage, but offsets the voltage harmonics generated by the GTO converters. A basic voltage control strategy for the hybrid converter system is proposed, and its validity is verified by experimental results. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 64–70, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20210