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No description available.

Insolvency of a dependant person and its group consequences Abstract The thesis deals with the consequences that the Czech Act on Business Corporations and the Insolvency Act provides for the case of bankruptcy of a dependant entity in relation to the remaining entities in the group. First, the general conceptual bases are discussed and the value of the principles of limited liability and individual legal personality in the context of the business group is explained. One chapter is devoted to international issues that arise in the context of bankruptcy within business groups, that is, both private international law and harmonization issues. The importance of harmonization is explained with reference to universalism, the leading way of thinking in solving cross-border bankruptcy, and in other parts of the thesis, Czech law is compared with the international standards of insolvency law of UNCITRAL and the World Bank. Furthermore, the ways in which the liability of a group member for the debts of an insolvent corporation can be inferred are analyzed. These include, in particular, the English law inspired wrongful trading regime contained in s. 68 of the Act on Business Corporations and the liability of the dominant entity for the debts of the dependant entity if the dominant entity causes the dependant entity...

Groundwater is a significant component of the world's water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and 'health' of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system. Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed. The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level. The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1 976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels. Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panrnictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution. The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Wester,,Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction. The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit fi-om understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.

Ce manuscrit est basé sur l'étude de l'interaction entre des purs courants de spin et parois de domaines magnétiques. Cet étude a été divisée en quatre parties. Dans la première partie, nous avons donné une explication détaillée du transport de spin dans des nano structure métalliques en utilisant trois approches différentes. La deuxième partie est focalisée sur l'utilisation d'un pur courant de spin pour induire le mouvement d'un paroi de domaine. Dans la troisième et quatrième partie nous avons mis en évidence deux nouvelle techniques d'injection et détection de spin en utilisant des parois des domaines magnétiques. / This thesis is based on the study of the interplay between pure spin currents and magnetic domains walls. This study has been divided in four chapters. In the first part, we provides a detailed explanation of the spin-transport in metallic structures by using three approaches. The second chapter concerns to the use of pure spin currents to induce DW motion in lateral spin valves. The third and four chapter, is mainly focused on the use of DWs for the efficient injection and detection of pure spin currents in lateral spin valves and cross shaped geometries.

Summary of doctoral dissertation introduces the object, purpose and tasks, the novelty, actuality and originality of the dissertation. As well as this, the methodology, sources and the structure of the dissertation are given. Main conclusions and results of the research are being presented. Finally, the list of scientific publications and personal details about the author of the dissertation are given. / Disertacijos santraukoje apibrėžiami darbo objektas, tikslai ir uždaviniai, taip pat mokslinio darbo naujumas, originalumas ir aktualumas. Kartu pateikiami pagrindiniai darbe naudoti metodai ir šaltiniai. Pristatomos pagrindinės ir svarbiausios moksliniame tyrime pasiektos išvados ir ginamieji teiginiai. Galiausiai pateikiama bendra informacija apie disertacijos autorę ir jos mokslinių publikacijų disertacijos tema sąrašas.

Plants are constantly exposed to pathogens and various environmental stresses, such as cold, salinity and drought. Plants normally respond rapidly to these biotic and abiotic stresses. Efficient perception of biotic and abiotic stresses and cell programmed signaling mechanisms for appropriate responses are important for growth and survival of plants. Calcium is an important second messenger in signaling pathways that respond to environmental stresses, pathogen attack as well as hormonal stimuli (For review, see DeFalco et al., 2010; Reddy and Reddy, 2004; Sanders et al., 2002). The transient increase of cytosolic free calcium concentration has been shown in a variety of external signals (Reddy, 2001), which in turn triggers many signal transduction pathways leading to a variety of cellular responses (Bush, 1995). Any calcium mediated signal transduction process involves generation of signal-specific calcium signature in the cytosol (Scrase-Field and Knight, 2003). These changes in cytosolic calcium level or ‘calcium signatures’ are sensed by the specific group of proteins called the ‘calcium sensors’. Different calcium sensors recognize specific calcium signatures and transduce them into downstream effects, including altered protein phosphorylation and gene expression patterns. In plants the protein kinases are a large and differentiated group of calcium sensors. After analyzing 1264 protein kinase sequences, a superfamily of protein kinase called CDPK/SnRK family of protein kinase were defined (Hrabak et al., 2003). CDPK/SnRK family of protein kinases encompasses five subfamilies viz., calcium-dependant protein kinases, (CPKs), calcium/calmodulin dependant protein kinases (CCaMKs), calmodulin-dependant protein kinases (CaMKs), CPKrelated kinases (CRKs), and SnF1 related kinase 3 (SnRK3) and are regulated by calcium directly or indirectly. Among these, in plants, calcium-dependant protein kinases (CPKs) are predominant calcium sensors, which are shown to be involved in myriads of physiological responses. They are Ser/Thr family of protein kinases typically made up of five domains with an Nterminal variable domain followed by catalytic protein kinase domain, an autoinhibitory/ junction domain, a regulatory calmodulin-like domain (CaMLD) and a Cterminal domain of variable length. The CPKs are unique due to the presence of CaMLD which couples the calcium sensor directly to its responder (kinase domain). Although CPKs are highly conserved, there are several features that distinguish different members of the plant CDPK family. In an attempt to investigate the role of a CPK isoform, in the present work we bring out the results and inferences on isolation and characterization of a novel cDNA encoding a calcium-dependant protein kinase isoform ScCPK1 from Swainsonacanescens, a pharmaceutically important Australian herb known to produce an anticancer drug, swainsonine. Initially, we have cloned an 800 bp partial CPK cDNA from S. canescens by reverse transcription polymerase chain reaction (RTPCR) using degenerate oligonucleotide primers designed based on conserved regions of the other known CPKs. A 2.1 kb full length CPK was obtained using 5` and 3` RACE which was designated as ScCPK1. An open reading frame (ORF) of 1659 bp was detected that encodes a protein of 552 amino acids with a calculated molecular mass of 61.8 kDa. Comparison of the deduced amino acid sequence of ScCPK1 with sequences of other CPKs revealed the highest identity (>90%) to Glycine max and Vigna radiate CPKs. As described for other CPKs, ScCPK1 has a long variable domain (88 aa), an auto-inhibitory domain (31 aa) and a C-terminal calmodulin domain (145 aa) containing four EF-hand calcium binding motifs, which is found in many CPKs. Phylogenetic tree analysis showed that ScCPK1 was closely related to StCPK4 , CmCPK1 and CmCPK2. The entire coding region of ScCPK1 was cloned into pRSETA expression vector and expressed as fusion protein in E.coli. The recombinant ScCPK1 protein was purified to homogeneity by NiNTA affinity chromatography. The recombinant purified ScCPK1 was catalytically active in a calcium-dependent manner. The recombinant ScCPK1 phosphorylated itself and histone IIIS as substrate only in the presence of Ca2+. Phosphoaminoacid analyses showed that ScCPK1 phosphorylates serine and threonine residues of histone IIIS and its autophosphorylation also occurs on serine and threonine residues. ScCPK1 has a pH and temperature optima of 7.5 and 37 °C, respectively. It showed high affinity to histone III-S with a Km of 4.8 µM and had a Vmax of 4.700 pmoles of γ32P incorporation/min/mg at saturating substrate concentrations. The ScCPK1 is ~100fold active and showed 10fold higher affinities to histone III-S than CaCPK1 and CaCPK2, CPKs which were characterized from Cicer arietinum previously in our laboratory (Prakash and Jayabaskaran, 2006). From literature it is known that many CPKs are activated or inhibited by metal ions. (PutnamEvans etal., 1990; Anil and Rao, 2001). The influence of Na+ and Mg2+on the in vitro substrate phosphorylation activity of the recombinant ScCPK1 was tested in this work. Addition of NaCl strongly inhibited ScCPK1 activity. The inhibition of substrate phosphorylation activity by salt implies ionic interactions between the positively charged substrate and the enzyme’s active site. The optimum concentration of Mg2+ for ScCPK1 substrate phosphorylation activity was found to be 810 mM, similar to CaCPK1 and CaCPK2 (Prakash and Jayabaskaran, 2006). However, the activity was inhibited above 10 mM Mg2+suggesting the disruption of ionic interactions between the enzyme and the substrate. The kinase and autophosphorylation activities of the recombinant ScCPK1 were calmodulin independent and sensitive to CaM antagonists’ calmidazolium and W7 (N(6aminohexyl)5chloronaphthalene sulphonate). This indicates that the activation was supported by calmodulin-like domain, which is typical of CPK family. Farmer and Choi (1999), showed that DcCPK1 activity was inhibited by polyamines vizspermine and spermidine, and polylysine. We found that substrate phosphorylation activity of ScCPK1 was inhibited by polyLLysine with an IC50 of 8 M but not the polyamines, spermine and spermidine. An interesting aspect that makes CPKs attractive for research is their functional similarity to mammalian PKCs. There are no structural PKC analogues found in plant genomic data. Similar to PKCs, CPKs are regulated by intracellular Ca2+ signals. There is also experimental evidence that some of the CPKs are additionally activated by phospholipids (Farmer and Choi, 1999; Szczegielniak etal., 2000). We investigated the effects of lipid molecules on the activity of ScCPK1. Phosphorylation of histone IIIS by ScCPK1 was stimulated by phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol in the presence of Ca2+, where as lysophosphatidylcholine, phosphatidylcholine and phosphatidic acid did not increase the enzyme activity. Our data that shows interaction of ScCPK1 with phospholipids supports the idea that this protein kinase could be associated with the membrane. The work from Farmer and Choi (1999), with DcCPK1 suggested that some of the PKClike activities observed in plants may be attributed to CPKs. They also demonstrated that DcCPK1 phosphorylated PKC pseudosubstrate peptide and also was sensitive to staurosporine inhibition. However, the protein kinase inhibitor, staurosporine inhibited the substrate phosphorylation activity of ScCPK1 completely with an IC50 value of 700 nM invitro. But PKC inhibitor PMA was less effective, inhibiting the substrate phosphorylation activity of ScCPK1 to a maximum of 50%, but at a very high concentration (200 nM). Our data suggests that ScCPK1 may not have any features attributable to PKC. We investigated subcellular localization of the ScCPK1. To gain a better understanding of the subcellular localization of the ScCPK1, we generated GFP fusion protein of ScCPK1 and transiently expressed it in Agrobacterium-mediated transformed tobacco BY2 cells. Analysis of the GFP expression patterns in transformed tobacco BY2 cells revealed ScCPK1 localization in the plasma membrane of the transformed tobacco BY2 cells despite lacking consensus myristoylation and palmitoylation motifs (as per in silico analyses). Taking together, our data have demonstrated that ScCPK1 is a Ser/Thr protein kinase and its sub-cellular localization studies revealed that it is localized to plasma membrane. We propose that ScCPK1 is a key component of one or more signaling pathways and plays vital roles in plant development, responses to environmental stimuli and/ or in secondary metabolite biosynthetic gene expression. The involvement of the ScCPK1 as a component of signaling pathways warrants further studies.

The dissertation focuses on the temperature dependent rate coefficient measurement of reactions in the interstellar medium using a coaxial molecular beam ring electrode ion trap apparatus. The first chapter introduces the previous studies of ion-molecule reactions in the ISM, the types of instruments mainly used in the reaction rate coefficient study, the former research on the ring electrode ion trap and the gas phase reaction mechanisms. Compare to other instruments, our molecular beam - ring electrode ion trap is extremely good at ion cooling and temperature control for both ions and neutral molecules. Chapter two describes each part of the instrument used in detail. Ions produced by electron impact in the ion source chamber, are mass filtered and then reach the ring electrode ion trap. In the trap, ions collide with molecules in the molecular beam where reaction takes place. When the reaction is done, all the ions remained in the trap (the reactant and product ions) come out and move to the detector. The molecular beam terminates at residual gas analyzer which is used for the number density calibration. The third chapter shows how the temperature of ions and molecules are controlled separately in order to find the reaction mechanism. Ions are cooled by the pulsed He buffer in the ring electrode trap and a chopped beam is used to make sure the ions are cooled to the desired low temperature when the reaction takes place. Chapters four to six describe the three reactions being studied using this instrument: N₂⁺ + H₂O charge transfer reaction, H₃O⁺ + C₂H₄ proton transfer reaction and H3O⁺ + (C₂H₂)₂/C₂H₂ dimer reaction. The temperature dependent rate coefficient data of these reactions are explained by the average dipole orientation theory, statistical theory and Colussi's acetylene dimer model, respectively. Two temperatures are defined and applied in the experimental rate coefficients analysis: ion-molecule center of mass collision temperature and the reaction statistical temperature which is based on the numbers of degrees of freedom of both reactants.

No description available.

Neisseria gonowhoeae has evolved a repertoire of high-affinity iron acquisition systems to facilitate essential iron uptake in the human host. Acquisition of iron requires both the energy-harnessing cytoplasmic membrane protein, TonB, as well as specific outer membrane TonB-dependent transporters (TdTs). The overall goal of this study was to investigate the extra- and intracellular iron acquisition mechanisms of N. gonorrhoeae and determine the role of the TonB and TdTs in this process.The ability of gonococci to acquire potential exogenous iron sources was determined by plate bioassay. Gonococcal growth was promoted by various catecholate and hydromate siderophores; however, growth was not dependent upon TonB expression.As all previously characterized siderophore-iron uptake is dependent upon this protein, apotential TonB-bypass mechanism is suggested.The role of the Ton system and TdTs in gonococcal survival within human cervicalepithelial cells was also determined for two gonococcal strains, FA1090 and MS 1 1. Wedemonstrate that intracellular survival of both strains was dependent upon host cell ironacquisition, yet the expression of the Ton system was only critical to the survival ofFA1090. One characterized difference between these two strains is possession of thegonococcal genetic island (GGI) which is present in approximately 80% of gonococcalstrains. This study demonstrates that the GGI provides a mechanism to bypassintracellular TonB-dependent iron acquisition.In the strain lacking the genetic island, none of the characterized TdTs provided abenefit to the gonococcus when grown intracellularly. However, expression of oneuncharacterized TdT, TdfF, was necessary for successful intracellular survival. To ourknowledge, this is the first demonstration of a specific requirement for a single irontransporter in the survival of a bacterial pathogen within host epithelial cells.In the GGI-containing strain, TonB function was not critical to survival withincervical epithelial calls. The presence of the GGI was associated with the ability to bypass TonB-dependant uptake. Specifically, this bypass mechanism was mediated bycomponents of the T4S machinery encoded by the GGI, and replication was directlyrelated to iron acquisition. To our knowledge, this study provides the first direct linkbetween bacterial iron acquisition and a type IV secretion system.