81 research outputs found

    Conversion in Turkish : an overview

    Get PDF
    This paper presents an overview of possible cases of conversion in Turkish. I argue that apparent cases of conversion between nouns and adjectives are cases of syntactic transposition, and apparent cases of conversion between nouns/adjectives and verbs are end products of phonological changes in the history of the language, which resulted in pairs of lexemes that are formally identical synchronically, but not historically. This does not mean that no cases of morphological conversion can be traced in the language. I will present two cases of secondary word-class conversion from derived, inflected and uninflected words to toponyms which might be taken as instances of morphological conversion or derivation by zero-affixation

    Acetate Kinase Isozymes Confer Robustness in Acetate Metabolism

    Get PDF
    Acetate kinase (ACK) (EC no: 2.7.2.1) interconverts acetyl-phosphate and acetate to either catabolize or synthesize acetyl-CoA dependent on the metabolic requirement. Among all ACK entries available in UniProt, we found that around 45% are multiple ACKs in some organisms including more than 300 species but surprisingly, little work has been done to clarify whether this has any significance. In an attempt to gain further insight we have studied the two ACKs (AckA1, AckA2) encoded by two neighboring genes conserved in Lactococcus lactis (L. lactis) by analyzing protein sequences, characterizing transcription structure, determining enzyme characteristics and effect on growth physiology. The results show that the two ACKs are most likely individually transcribed. AckA1 has a much higher turnover number and AckA2 has a much higher affinity for acetate in vitro. Consistently, growth experiments of mutant strains reveal that AckA1 has a higher capacity for acetate production which allows faster growth in an environment with high acetate concentration. Meanwhile, AckA2 is important for fast acetate-dependent growth at low concentration of acetate. The results demonstrate that the two ACKs have complementary physiological roles in L. lactis to maintain a robust acetate metabolism for fast growth at different extracellular acetate concentrations. The existence of ACK isozymes may reflect a common evolutionary strategy in bacteria in an environment with varying concentrations of acetate

    Guided Elastic Interface Waves for Ceramic Joint Evaluation

    Get PDF
    Because of their excellent thermal and wear properties, structural ceramics are finding increasing use in applications that have traditionally been reserved for metals. Since many ceramics remain stable at temperatures well in excess of the melting points of virtually all of the common structural metals, one such application is in high-temperature engines, where the relatively low weight of ceramics provides an additional advantage over such competitors as refractory metals. Unfortunately, with the relatively low fracture toughness and poor machinability of ceramics, practical designs, at least for the near future, will probably consist of ceramic liners attached to metal substrates, thereby combining the wear and thermal properties of ceramics with the strength of metals.</p

    The Reflection of Ultrasound from Interface Layers in Adhesive Joints

    Full text link
    The detection of a weak adhesive/adherend interface in an adhesive joint is one of the major current challenges in NDE; the lack of a satisfactory non destructive test for this region is retarding the exploitation of the advantages of adhesive bonding in safety critical areas. It is the interface layer which is affected by the common problem of slight contamination due to, for example, grease on the adherend surfaces prior to bonding. The interface is particularly important in aluminium-aluminium joints in which an inappropriate interface structure can cause greatly enhanced susceptibility to environmental attack [1]. Inspection of the interface layer is difficult because it is frequently only of the order of lμm thick, compared with an adhesive layer thickness of the order of 100 μm.</p

    IL-6 signaling by STAT3 participates in the change from hyperplasia to neoplasia in NRP-152 and NRP-154 rat prostatic epithelial cells

    Get PDF
    BACKGROUND: STAT3 phosphorylation is associated with the neoplastic state in many types of cancer, including prostate cancer. We investigated the role of IL-6 signaling and phosphorylation of STAT3 in 2 rat prostatic epithelial lines. NRP-152 and NRP-154 cells were derived from the same rat prostate, yet the NRP-152 cells are not tumorigenic while the NRP-154 cells are tumorigenic. These lines are believed to represent 2 of the stages in the development of prostate cancer, hyperplasia and neoplasia. Differences in signaling pathways should play a role in the 2 phenotypes, hyperplastic and neoplastic. METHODS: We looked at the phosphorylation state of STAT3 by intracellular flow cytometry, using phospho-specific antibodies to STAT3. We used the same method to examine IL-6 production by the cell lines. We also measured apoptosis by binding of fluorescent annexin V to the cells. RESULTS: Although both cells lines made IL-6 constitutively, phosphorylated-STAT3 was present in untreated NRP-154 cells, but not in NRP-152 cells. Treatment with dexamethasone inhibited the IL-6 production of NRP-152 cells, but enhanced that of NRP-154 cells. Treatment with the JAK2 inhibitor AG490 induced apoptosis in NRP-152, but not NRP-154 cells. CONCLUSIONS: We conclude from these experiments that STAT3 activity plays a role in the phenotype of NRP-154 cell, but not NRP-152 cells. The significance of alternative IL-6 signaling pathways in the different phenotypes of the 2 cell lines is discussed
    corecore