Coordination polymeric structures in the sodium salt of 4-chloro-3-nitrobenzoic acid and the sodium and potassium salts of 4-nitroanthranilic acid

The structures of the hydrated sodium salts of 4-chloro-3-nitrobenzoic acid {poly[aqua(μ4-4-chloro-3-nitrobenzoato)sodium(I)], [Na(C7H3ClNO4)(H2O)]n, (I)} and 2-amino-4-nitrobenzoic acid {poly[μ-aqua-aqua(μ3-2-amino-4-nitrobenzoato)sodium(I)], [Na(C7H5N2O4)(H2O)2]n, (II)}, and the hydrated potassium salt of 2-amino-4-nitrobenzoic acid {poly[μ-aqua-aqua(μ5-2-amino-4-nitrobenzoato)potassium(I)], [K(C7H5N2O4)(H2O)]n, (III)} have been determined and their complex polymeric structures described. All three structures are stabilized by intra- and intermolecular hydrogen bonding and strong π–π ring interactions. In the structure of (I), the distorted trigonal bipyrimidal NaO5 coordination polyhedron comprises a monodentate water molecule and four bridging carboxylate O-atom donors, generating a two-dimensional polymeric structure lying parallel to (001). Intra-layer hydrogen-bonding associations and strong inter-ring π–π interactions are present. Structure (II) has a distorted octahedral NaO6 stereochemistry, with four bridging O-atom donors, two from a single carboxylate group and two from a single nitro group and three from the two water molecules, one of which is bridging. Na centres are linked through centrosymmetric four-membered duplex water bridges and through 18-membered duplex head-to-tail ligand bridges. Similar centrosymmetric bridges are found in the structure of (III), and in both (II) and (III) strong inter-ring π–π interactions are found. A two-dimensional layered structure lying parallel to (010) is generated in (II), whereas in (III) the structure is three-dimensional. With (III), the irregular KO7 coordination polyhedron comprises a doubly bridging water molecule, a single bidentate bridging carboxylate O-atom donor and three bridging O-atom donors from the two nitro groups. A three-dimensional structure is generated. These coordination polymer structures are among the few examples of metal complexes of any type with either 4-chloro-3-nitrobenzoic acid or 4-nitroanthranilic acid.

Tyrosine phosphorylation mediates ConA-induced membrane type 1-matrix metalloproteinase expression and matrix metalloproteinase-2 activation in MDA-MB-231 human breast carcinoma cells

ConA-induced cell surface activation of pro-matrix metalloproteinase-2 (pro-MMP-2) by MDA-MB-231 human breast cancer cells is apparently mediated by up-regulation of membrane type 1 MMP (MT1-MMP) through transcriptional and posttranscriptional mechanisms. Here, we have explored the respective roles of cell surface clustering and protein tyrosine phosphorylation in the ConA- induction effects. Treatment with succinyl-ConA, a variant lacking significant clusterability, partially stimulated MT1-MMP mRNA and protein levels but did not induce MMP-2 activation, suggesting that clustering contributes to the transcriptional regulation by ConA but appears to be critical for the nontranscriptional component. We further found that genistein, an inhibitor of tyrosine phosphorylation, blocked ConA-induced pro-MMP-2 activation and ConA-induced MT1-MMP mRNA level in a dose-dependent manner, implicating tyrosine phosphorylation in the transcriptional aspect. This was confirmed by the dose-dependent promotion of pro-MMP-2 activation by sodium orthovanadate in the presence of suboptimal concentrations of ConA (7.5 μg/ml), with optimal effects seen at 25 μg/g orthovanadate. Genistein did not inhibit the ConA potentiation of MMP-2 activation in MCF-7 cells, in which transfected MT1-MMP is driven by a heterologous promoter, supporting the major implication of phosphotyrosine in the transcriptional component of ConA regulation. These data describe a major signaling event upstream of MT1- MMP induction by ConA and set the stage for further analysis of the nontranscriptional component.

Narratives of possession : reading for saga authorship

The aim of this thesis is to show how character analysis can be used to approach conceptions of saga authorship in medieval Iceland. The idea of possession is a metaphor that is adopted early in the thesis, and is used to describe Icelandic sagas as works in which traditional material is subtly interpreted by medieval authors. For example, we can say that if authors claim greater possession of the sagas, they interpret, and not merely record, the sagas' historical information. On the other hand, tradition holds onto its possession of the narrative whenever it is not possible for an author to develop his own creative and historical interests. The metaphor of possession also underpins the character analysis in the thesis, which is based on the idea that saga authors used characters as a vehicle by which to possess saga narratives and so develop their own historical interests. The idea of possession signals the kinds of problems of authorship study which are addressed here, in particular, the question of the authors' sense of saga writing as an act either of preservation or of creation. While, in that sense, the thesis represents an additional voice in a long-standing debate about the saga writers' relation to their source materials, I argue against a clear-cut distinction between creative and non-creative authors, and focus instead on the wide variation in authorial control over saga materials. This variation suggests that saga authorship is a multi-functional activity, or one which co-exists with tradition. Further, by emphasising characterisation as a method, I am adding to the weight of scholarship that seeks to understand the sagas in terms of their literary effects. The Introduction and chapter one lay out the theoretical scope of this thesis. My aim in these first two sections is to inform the reader of the type of critical questions that arise when authorship is approached in relation to characterisation, and to suggest an interpretive framework with which to approach these questions. In the Introduction this aim manifests as a brief discussion of the application of the term "authorship" to the medieval Icelandic corpus, a definition of the scope of this study, and an introduction to the connections, made throughout this thesis, between saga authors, the sagas' narrative style, and the style of characterisation in the sagas. Chapter one is a far more detailed discussion of our ability to make these connections. In particular, the chapter develops the definition of the analytical term "secondary authorship" that I introduce in order to delineate the type of characterisation that is of most interest in this thesis. "Secondary authorship" is a literary term that aims to sharpen our approach to saga authors' relationship to their characters by focusing on characters who make representations about the events of the saga. The term refers to any instance in which characters behave in a manner that resembles the creativity, interpretation, and understanding associated with authorship more generally. Character analysis cannot, however, be divorced from socio-historical approaches to the saga corpus. Most importantly, the sagas themselves are socio-historical representations that claim some degree of truth value. This claim that the sagas make by implication about their historicity is the starting point of a discussion of authorship in medieval Iceland. Therefore, at the beginning of chapter one I discuss some of the approaches to the social context of saga writing. This discussion serves as an introduction to both the culture of saga writing in medieval Iceland and to the nature of the sagas' historical perspective, and reflects my sense that literary interpretations of the sagas cannot be isolated from the historical discourses that frame them. The chapter also discusses possession, which, as I note above, is used alongside the concept of secondary authorship to describe the saga authors' relationship with the stories and characters of the past. At the close of chapter one, I offer a preliminary list the various functions of saga authorship, and give some examples of secondary authorship. From this point I am able to tie my argument about secondary authorship to specific examples from the sagas. Chapter two examines the effect of family obligations and domestic points of view in the depiction of characters' choices and conception of themselves. The examples that are given in that chapter - from Gisla saga Súrssonar and Íslendinga saga - are the first of a number of textual analyses that demonstrate the application of the concepts of secondary authorship and possession of saga narratives. The relationship between narratives about national and domestic matters shows how authorial creativity in the area of kinship obligation provides the basis for the saga's development of historical themes. Thus, the two major case studies given in chapter two tie authorial engagement with characters to the most influential social institution in early and medieval Iceland, the family. The remaining chapters represent similar attempts to relate authorial possession of saga characters to central socio-historical themes in the sagas, such as the settlement process in early Iceland and its influence on the development of regional political life (chapter three). Likewise, the strong authorial interest in an Icelander's journey to Norway in Heimskringla is presented as evidence of the author's use of a saga character to express an Icelandic interpretation of Norwegian history and to promote a sense that Iceland shared the ownership of regal history with Norway (chapter four). In that authorial engagement with the Icelander abroad, we witness saga characterisation being used as a basis for historical interpretation and the means by which foreign traditions and influence, not least the narratives of royal lives and of the Christianisation, are claimed as part of medieval Icelanders' self-conception. While saga authors observe the conventions of saga narration, characters are often subtly positioned as the authors' interpretive mirrors, especially clear than when they act as secondary authors. Nowhere is this more apparent than in Brennu- Njáls saga, which contains many characters who voice the author's claim to interpret the past. Even Hrútr Herjólfsson, through his remarkable perception of events and his conspicuous comments about them, acts as a secondary author by enabling the author to emphasise the importance of the disposition of characters. In Laxdœla saga and Þorgils saga ok Hafliða, authorial interest in characters' perception is matched by the thematising of learning, from the inception of knowledge as prophecy or advice to complete understanding by saga characters (chapter six). In Þorgils saga skarða, a character's inner development from an excessively ambitious and politically ruthless youth to a Christian leader killed by his kinsman allows the author to shape a political life into a lesson about leadership and the community's ability to moderate and contain the behaviour of extraordinary individuals. The portrayal draws on methods of characterisation that we can identify in Grettis saga Ásmundarson, Fóstbrœðra saga, and Orkneyinga saga. A comparison of the characterisation of figures with intense political or military ambitions suggests that saga authors were interested in the community's ability to balance their strength and ability with a degree of social moderation. The discussion of these sagas shows that character study can be used to analyse how the saga authors added their own voice to the voices passed down to medieval Icelanders in traditional narratives. Authorial engagement with characters allowed inherited traditions about early Norway and Iceland and records of thirteenth century events to be transformed into sophisticated historical works with highly creative elements. Through secondary authorship, saga authors took joint-possession of narratives and contested the power of tradition in setting the interpretive framework of a saga.

Terrestrial invertebrates of dry river beds are not simply subsets of riparian assemblages

Dry river beds are common worldwide and are rapidly increasing in extent due to the effects of water management and prolonged drought periods due to climate change. While attention has been given to the responses of aquatic invertebrates to drying rivers, few studies exist on the terrestrial invertebrates colonizing dry river beds. Dry river beds are physically harsh and they often differ substantially in substrate, topography, microclimate and inundation frequency from adjacent riparian zones. Given these differences, we predicted that dry river beds provide a unique habitat for terrestrial invertebrates, and that their assemblage composition differs from that in adjacent riparian zones. Dry river beds and riparian zones in Australia and Italy were sampled for terrestrial invertebrates with pitfall traps. Sites differed in substrate type, climate and flow regime. Dry river beds contained diverse invertebrate assemblages and their composition was consistently different from adjacent riparian zones, irrespective of substrate, climate or hydrology. Although some taxa were shared between dry river beds and riparian zones, 66 of 320 taxa occurred only in dry river beds. Differences were due to species turnover, rather than shifts in abundance, indicating that dry river bed assemblages are not simply subsets of riparian assemblages. Some spatial patterns in invertebrate assemblages were associated with environmental variables (irrespective of habitat type), but these associations were statistically weak. We suggest that dry river beds are unique habitats in their own right. We discuss potential human stressors and management issues regarding dry river beds and provide recommendations for future research.

Authentication of concast communication

In this paper we tackle the problem of finding an efficient signature verification scheme when the number of signatures is signi.- cantly large and the verifier is relatively weak. In particular, we tackle the problem of message authentication in many-to-one communication networks known as concast communication. The paper presents three signature screening algorithms for a variant of ElGamal-type digital signatures. The cost for these schemes is n applications of hash functions, 2n modular multiplications, and n modular additions plus the verification of one digital signature, where n is the number of signatures. The paper also presents a solution to the open problem of finding a fast screening signature for non-RSA digital signature schemes.

No genetic bottleneck in Plasmodium falciparum wild-type Pfcrt alleles reemerging in Hainan Island, China, following high-level chloroquine resistance

Chloroquine-resistant Plasmodium falciparum was highly prevalent in Hainan, China, in the 1970s. Twenty-five years after cessation of chloroquine therapy, the prevalence of P. falciparum wild-type Pfcrt alleles has risen to 36% (95% confidence interval, 22.1 to 52.4%). The diverse origins of wild-type alleles indicate that there was no genetic bottleneck caused by high chloroquine resistance.

Electrical characteristics of lateral heterostructure organic field-effect bipolar transistors

We describe and discuss the unique electrical characteristics of an organic field-effect transistor in which the active layer consists of a type II lateral heterojunction located approximately midway between the source and drain. The two active semiconductors on either side of the junction transport only one carrier type each, with the other becoming trapped, which leads to devices that operate in only the steady state when there is balanced electron and hole injections from the drain and source. We describe the unique transfer characteristics of such devices in two material systems.

Developing an evaluation framework for hospital disaster resilience : tertiary hospitals of Shandong Province, China

This thesis provided a definition and conceptual framework for hospital disaster resilience; it used a mixed-method, including an empirical study in tertiary hospitals of Shandong Province in China, to devise an assessment instrument for measuring hospital resilience. The instrument is the first of its type and will allow hospitals to measure their resilience levels. The concept of disaster resilience has gained prominence in the light of the increased impact of various disasters. The notion of resilience encompasses the qualities that enable the organisation or community to resist, respond to, and recover from the impact of disasters. Hospital resilience is essential as it provides 'lifeline' services which minimize disaster impact. This thesis has provided a framework and instrument to evaluate the level of hospital resilience. Such an instrument could be used to better understand hospital resilience, and also as a decision-support tool for its promoting strategies and policies.

Global dissemination of a multidrug resistant Escherichia coli clone

Escherichia coli sequence type 131 (ST131) is a globally disseminated, multidrug resistant (MDR) clone responsible for a high proportion of urinary tract and bloodstream infections. The rapid emergence and successful spread of E. coli ST131 is strongly associated with several factors, including resistance to fluoroquinolones, high virulence gene content, the possession of the type 1 fimbriae FimH30 allele, and the production of the CTX-M-15 extended spectrum β-lactamase (ESBL). Here, we used genome sequencing to examine the molecular epidemiology of a collection of E. coli ST131 strains isolated from six distinct geographical locations across the world spanning 2000–2011. The global phylogeny of E. coli ST131, determined from whole-genome sequence data, revealed a single lineage of E. coli ST131 distinct from other extraintestinal E. coli strains within the B2 phylogroup. Three closely related E. coli ST131 sublineages were identified, with little association to geographic origin. The majority of single-nucleotide variants associated with each of the sublineages were due to recombination in regions adjacent to mobile genetic elements (MGEs). The most prevalent sublineage of ST131 strains was characterized by fluoroquinolone resistance, and a distinct virulence factor and MGE profile. Four different variants of the CTX-M ESBL–resistance gene were identified in our ST131 strains, with acquisition of CTX-M-15 representing a defining feature of a discrete but geographically dispersed ST131 sublineage. This study confirms the global dispersal of a single E. coli ST131 clone and demonstrates the role of MGEs and recombination in the evolution of this important MDR pathogen.

F9 fimbriae of uropathogenic Escherichia coli are expressed at low temperature and recognise Galβ1-3GlcNAc-containing glycans

Uropathogenic Escherichia coli (UPEC) is the leading causative agent of urinary tract infections (UTI) in the developed world. Among the major virulence factors of UPEC, surface expressed adhesins mediate attachment and tissue tropism. UPEC strains typically possess a range of adhesins, with type 1 fimbriae and P fimbriae of the chaperone-usher class the best characterised. We previously identified and characterised F9 as a new chaperone-usher fimbrial type that mediates biofilm formation. However, the regulation and specific role of F9 fimbriae remained to be determined in the context of wild-type clinical UPEC strains. In this study we have assessed the distribution and genetic context of the f9 operon among diverse E. coli lineages and pathotypes and demonstrated that f9 genes are significantly more conserved in a UPEC strain collection in comparison to the well-defined E. coli reference (ECOR) collection. In the prototypic UPEC strain CFT073, the global regulator protein H-NS was identified as a transcriptional repressor of f9 gene expression at 37°C through its ability to bind directly to the f9 promoter region. F9 fimbriae expression was demonstrated at 20°C, representing the first evidence of functional F9 fimbriae expression by wild-type E. coli. Finally, glycan array analysis demonstrated that F9 fimbriae recognise and bind to terminal Galβ1-3GlcNAc structures.

Impact of al passivation and cosputter on the structural property of β-FeSi2 for Al-Doped β-FeSi2/ n -Si(100) based solar cells application

The aluminum (Al) doped polycrystalline p-type β-phase iron disilicide (p-β-FeSi2) is grown by thermal diffusion of Al from Al-passivated n-type Si(100) surface into FeSi2 during crystallization of amorphous FeSi2 to form a p-type β-FeSi 2/n-Si(100) heterostructure solar cell. The structural and photovoltaic properties of p-type β-FeSi2/n-type c-Si structures is then investigated in detail by using X-ray diffraction, Raman spectroscopy, transmission electron microscopy analysis, and electrical characterization. The results are compared with Al-doped p-β-FeSi2 prepared by using cosputtering of Al and FeSi2 layers on Al-passivated n-Si(100) substrates. A significant improvement in the maximum open-circuit voltage (Voc) from 120 to 320 mV is achieved upon the introduction of Al doping through cosputtering of Al and amorphous FeSi2 layer. The improvement in Voc is attributed to better structural quality of Al-doped FeSi2 film through Al doping and to the formation of high quality crystalline interface between Al-doped β-FeSi2 and n-type c-Si. The effects of Al-out diffusion on the performance of heterostructure solar cells have been investigated and discussed in detail.

The effects of exercise and adipose tissue lipolysis on plasma adiponectin concentration and adiponectin receptor expression in human skeletal muscle

Objective It has been suggested that adiponectin regulates plasma free fatty acid (FFA) clearance by stimulating FFA uptake and/or oxidation in muscle. We aimed to determine changes in plasma adiponectin concentration and adiponectin receptor 1 and 2 mRNA expression in skeletal muscle during and after prolonged exercise under normal, fasting conditions (high FFA trial; HFA) and following pharmacological inhibition of adipose tissue lipolysis (low FFA trial; LFA). Furthermore, we aimed to detect and locate adiponectin in skeletal muscle tissue. Methods Ten subjects performed two exercise trials (120 min at 50% VO2max). Indirect calorimetry was used to determine total fat oxidation rate. Plasma samples were collected at rest, during exercise and during post-exercise recovery to determine adiponectin, FFA and glycerol concentrations. Muscle biopsies were taken to determine adiponectin protein and adiponectin receptor 1 and 2 mRNA expression and to localise intramyocellular adiponectin. Results Basal plasma adiponectin concentrations averaged 6.57±0.7 and 6.63±0.8 mg/l in the HFA and LFA trials respectively, and did not change significantly during or after exercise. In the LFA trial, plasma FFA concentrations and total fat oxidation rates were substantially reduced. However, plasma adiponectin and muscle adiponectin receptor 1 and 2 mRNA expression did not differ between trials. Immunohistochemical staining of muscle cross-sections showed the presence of adiponectin in the sarcolemma of individual muscle fibres and within the interfibrillar arterioles. Conclusion Plasma adiponectin concentrations and adiponectin receptor 1 and 2 mRNA expression in muscle are not acutely regulated by changes in adipose tissue lipolysis and/or plasma FFA concentrations. Adiponectin is abundantly expressed in muscle, and, for the first time, it has been shown to be present in/on the sarcolemma of individual muscle fibres.