NF‐IL6 is a nuclear factor that specifically binds to an IL1‐responsive element in the IL‐6 gene. In this study the gene encoding NF‐IL6 has been cloned by direct screening of a lambda gt11 library using NF‐IL6 binding sequence as a ligand. The full‐length cDNA encoded a 345 amino acid protein with a potential leucine zipper structure and revealed a high degree of homology to a liver‐specific transcriptional factor, C/EBP, at the C‐terminal portion. The bacterial fusion protein bound to the CCAAT homology as well as the viral enhancer core sequences as in the case of C/EBP. Recombinant NF‐IL6 activated the human IL‐6 promoter in a sequence‐specific manner. Southern blot analysis demonstrated the high‐degree conservation of the NF‐IL6 gene through evolution and the existence of several other related genes sharing the DNA‐binding domain. NF‐IL6 mRNA was normally not expressed, but induced by the stimulation with either LPS, IL‐1 or IL‐6. Interestingly, NF‐IL6 was shown to bind to the regulatory regions for various acute‐phase protein genes and several other cytokine genes such as TNF, IL‐8 and G‐CSF, implying that NF‐IL6 has a role in regulation not only for the IL‐6 gene but also for several other genes involved in acute‐phase reaction, inflammation and hemopoiesis.

The interleukin-6 (IL-6) promoter is rapidly and transiently activated with other cytokines, including IL-1, tumor necrosis factor, and platelet-derived growth factor, as well as phorbol esters and agents that increase intracellular cyclic AMP. In this study, we have investigated cis-acting regulatory elements and trans-acting factors responsible for IL-i-induced IL-6 gene expression. Studies on the 5' deletion mutants of the human IL-6 gene suggested that the IL-i-responsive element was mapped within the IL-6 promoter region (-180 to -123) which was homologous to the c-fos serum-responsive enhancer element. Gel retardation assay identified two types of nuclear factors that bound to this region, one constitutive and the other inducible. These two factors recognized a 14-base-pair (bp) palindromic sequence, ACATTGCACAATCT. Furthermore, three copies of this 14-bp palindrome conferred IL-1 responsiveness to the basal enhancerless IL-6 promoter, indicating that a 14-bp-dyad symmetry sequence was an IL-i-responsive element in the IL-6 gene.

NF-IL6 was originally identified as a DNA binding protein regulating interleukin-1 (IL-1)-stimulated IL-6 expression. Direct cloning of NF- IL6 showed its homology with C/EBP, a hepatocyte- and adipocyte- specific transcription factor. This study showed that the expression of NF-IL6 messenger RNA (mRNA) increased markedly during the differentiation to a (mRNA) increased markedly during the differentiation to a macrophage lineage in mouse myeloid leukemia cells M1, human histiocytic leukemia cells U937, promyelocytic leukemia cells HL-60, and human peripheral monocytes. Particularly in HL-60 cells that undergo granulocyte or macrophage differentiation depending on inducers, NF-IL6 mRNA was specifically upregulated during macrophage differentiation but not granulocyte differentiation. It was also shown that the functional NF-IL6 protein increased during the differentiation of U937 cells. Furthermore, recombinant NF-IL6 was found to bind to the regulatory regions of the IL-1, tumor necrosis factor, granulocyte colony-stimulating factor, and lysozyme genes, which are expressed in mature macrophages. These results suggest that NF-IL6 may possibly be involved as an important transcription factor in the process of activation and/or differentiation of macrophages.

A new tsunami observation system has been developed, which employs the RTK-GPS technique to detect a tsunami before it reaches the coast. The system consists of dual-buoys: the Support-buoy, which is sensitive to wind-waves, and the Sensor-buoy, which is of a spar-type and is insensitive to wind-waves. Both buoys are equipped with a GPS antenna. An experiment using this system was carried out for about nine days in March 1999. Observation data were monitored at the onshore base station. The results showed that hourly averaged data is consistent with ocean tides for both buoys. The Sensor-buoy was found not to respond much to wind-waves compared to the Support-buoy. Thus, it may be preferable to use a spar-type buoy for detecting a tsunami efficiently. Furthermore, a simple frequency analysis showed that a tsunami could be easily separated from higher frequency wind waves if a tsunami is superimposed on regular wind waves.

A seaworthy ship must have the ability to endure the constantly changing and sometimes harsh environments of the ocean. Stable operation of a ship is important not only to prevent capsizing, but also to maintain an acceptable level of comfort for the crew. When navigating through waves, a ship experiences greater resistance, which adversely affects its speed and stability. Hence, one of the most important goals of research and development in naval architecture is to stabilize a ship’s movement in waves. Insects, birds, and fish use wings and fins to maintain stability and to generate thrust. Drawing from these examples in nature, researchers have investigated the employment of wings to transform wave energy into propulsion and to improve a ship’s stability. Research has shown that bow wings can generate thrust while simultaneously enhancing ship stability. In this paper, we review various strategies for improved bow wing technologies. Both theoretical and experimental efforts are reviewed. The effects of wing shape, size, position, and stiffness on the characteristics of thrust and resistance are detailed. Various control and energy conversion strategies are discussed. Perspectives for further research and development are also presented.