Analysis of interaction between stretched pulses propagating indispersion-managed fibers

Mutual interaction between a pair of stretched pulses propagating in periodically amplified dispersion-managed fibers is analyzed by means of the variational method. It is shown that the location of the amplifier within a unit cell of the dispersion management significantly affects the energy enhancement and interaction between adjacent pulses. The collapse distance of the two pulses can be extended by suitably positioning the amplifier     

Mutational analysis of the N-ras gene in acute lymphoblastic leukemia: a study of 125 Japanese pediatric cases

Many antibiotic resistance mutations arise in pathogenic bacteria that harbor plasmids (R-plasmids). Resistance to third generation cephalosporins, for instance, largely occurs by one or more point mutations in plasmid bla genes that expand the resistance spectrum of beta-lactamases. Here I review relevant evidence underlying the worldwide emergence of extended spectrum beta-lactamases (ESBLs). The conclusion reached is that the origin of these resistance-conferring mutations cannot be explained by a series of single point mutation and selection events. Instead, highly advantageous stochastic processes might exist that generate alterations in the sequence or the conformation of particular regions in chromosomal or plasmid genomes such as bla, i.e., recombination or mutation. Several explanations for the origin of ESBLs are reviewed but direct experimental evidence to support or to invalidate them is still lacking. The cellular conditions under which ESBLs arise are unknown; however, involvement of nutritional stresses inside natural animal hosts and of plasmid conjugal functions appear likely.     

Experimental study of large rectenna array for microwave energytransmission

For a field experiment on microwave power transmission (MPT) which was jointly conducted by the Radio Atmospheric Science Center of Kyoto University, Robe University, and Kansai Electric Power Company from 1994 to 1995, we had developed and tested a new type of rectenna (rectifying antenna) based on a circular microstrip antenna (CMA). A square shape of array with an area of 3.2 m×3.6 m was then constructed using the developed rectennas for experiment. The whole rectenna array is composed of 256 sub-arrays, each with nine rectenna elements. We place the rectenna sub-array with better RF-DC conversion efficiency in the central area of the whole rectenna array. Such spatial optimization is needed because the power density of the microwave beam used in the experiment has a spatial gradient with a peak at the center of the beam. We then examined dependence of the rectenna array characteristics on the electrical connection of the sub-arrays. The difference of the output DC power of the whole array for five different electrical connections is within 5%. The load characteristics, therefore, suffers little change even if the electrical connection of the rectenna sub-array is changed     

Thermal fatigue and aging properties of water-impervious cable

On-core water impervious power cable has a water-impervious layer consisting of lead foil and a semiconducting plastic film. This layer is thermally bounded to the insulation shield of the cable core and prevents ingress of water to its interior. According to this design, the water-impervious layer is subjected to thermal expansion and contraction directly from the core and, as a result, thermal fatigue properties assume greater importance. Factors such as strain in the water-impervious layer, aging behavior of the lead foil, heat cycle behavior on the cable, and high-temperature behavior of composite tapes were investigated. Based on these results, it is estimated that the life of the on-core water-impervious layer is approximately 40 yrs     

Changes of immunological markers after autologous peripheral blood stem cell transplantation

PURPOSE: Recently high-dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) has become an important treatment for hematological and solid tumors. METHODS: Immunological parameters were examined before and after PBSCT in 9 patients with lung cancer and 13 patients with malignant lymphoma. Findings were compared with those for bone marrow transplantation (BMT). Peripheral blood cells were analyzed for phenotype and the levels of cytokines and soluble factors were measured. RESULTS: After PBSCT, activated T cells (CD3+HLA-DR+ cells, CD8+HLA-DR+ cells) and suppressor/cytotoxic T cells (CD8+CD11b- cells) were significantly higher in the patients with lung cancer than in those with malignant lymphoma. Serum levels of interleukin-4 and soluble interleukin-2 receptor were also significantly higher in the patients with lung cancer than in those with lymphoma. On the other hand, the serum levels of interferon gamma, tumor necrosis factor alpha, interleukin-6, soluble human leukocyte antigen class 1, and soluble thrombomodulin were significantly increased after bone marrow transplantation. The transfused peripheral stem cells of lung cancer and lymphoma patients had a similar number of granulocyte/macrophage-colony-forming units, but lung cancer patients had significantly more CD34-positive cells. CONCLUSION: By reinfusing large numbers of autologous immune cells, PBSCT may accelerate immune reconstitution, with T cells being likely to have a marked therapeutic potential. The changes after PBSCT were greater in patients with lung cancer than in lymphoma patients. These blood cells are potent mediators of anticancer activity and could play an important role in the elimination of autologous malignant cells.     

Assignment of the human connexin43 gene, GJA1, to chromosome 6q22.3

Metabolism is probably disturbed in patients with abnormal liver function who have undergone a successful Kasai procedure. We examined bone mineral metabolism in patients who have successfully undergone Kasai procedure. Bone mineral metabolism was examined in 8 patients with biliary atresia after a successful Kasai procedure. Five patients were female and 3 were male. The ages at Kasai procedure ranged from 50 to 80 days, and the follow-up periods ranged from 3 to 27 years after the operation. All patients eat a normal oral diet. We examined plasma levels of 25-OH-D3, 1, 25-(OH)2-D3, Ca and phosphorus (P). Bone mineral content of the lumbar spine (L2-L4) was assessed by dual energy x-ray absorptiometry (DEXA), and the data were expressed as a bone mineral density (BMD). Two patients showed abnormal levels on hepatic function tests. Plasma levels of 1, 25-(OH)2-D3, Ca, and P were normal in all patients. The level of 25-OH-D3 was normal in 7 patients. BMD levels were normal in 6 patients, but low in 2 who had undergone partial splenic embolization and splenectomy, respectively, due to hypersplenism. In long-term survivors of Kasai procedure, measurement of BMD may detect bone mineral deficiency earlier than measurements of serum levels of 25-OH-D, 1, 25-(OH)2-D, Ca and P.     

Narrow-beam and power-penalty-free 1.3-/spl mu/m laser diodes with monolithically integrated waveguide lens formed by selective-area epitaxial growth

A narrow-beam has been realized in a 1.3 /spl mu/m Fabry-Perot laser diode monolithically integrated with a tapered waveguide lens. The beam divergences in the perpendicular and horizontal directions are reduced down to 12/spl deg/ and 11/spl deg/ by a selective area epitaxial growth technique. The threshold current has been kept as low as 14 mA comparable to the conventional ones. Neither kinks in the L-I curves nor changes of far-field patterns are observed in the wide temperature range from -40 to 80/spl deg/C. Furthermore, high cut-off frequency over 4 GHz and power penalty-free characteristic under 622 Mb/s-50 km transmission have been confirmed.     

Nonadipose tissue production of leptin: leptin as a novel placenta-derived hormone in humans

Leptin is a circulating hormone that is expressed abundantly and specifically in the adipose tissue. It is involved in the regulation of energy homeostasis, as well as the neuroendocrine and reproductive systems. Here, we demonstrate production of leptin by nonadipose tissue, namely, placental trophoblasts and amnion cells from uteri of pregnant women. We show that pregnant women secrete a considerable amount of leptin from the placenta into the maternal circulation as compared with nonpregnant obese women. Leptin production was also detected in a cultured human choriocarcinoma cell line, BeWo cells, and was augmented during the course of forskolin-induced differentiation of cytotrophoblasts into syncytiotrophoblasts. Plasma leptin levels were markedly elevated in patients with hydatidiform mole or choriocarcinoma and were reduced after surgical treatment or chemotherapy. Leptin is also produced by primary cultured human amnion cells and is secreted into the amniotic fluid. The present study provides evidence for leptin as a novel placenta-derived hormone in humans and suggests the physiologic and pathophysiologic significance of leptin in normal pregnancy and gestational trophoblastic neoplasms.