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Major Driving Force (major + driving_force)
Selected Abstracts(4-Acyl-5-pyrazolonato)titanium Derivatives: Oligomerization, Hydrolysis, Voltammetry, and DFT StudyEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2003Francesco Caruso Abstract Twenty 4-acyl-5-pyrazolonato (Q) titanium derivatives of varied nuclearity have been synthesized from Ti(OR)4 or TiCl4 and characterized with spectroscopic methods (IR, NMR, ESI-MS). While Ti,(,-diketonato) cleavage is not seen in isolated solids, Ti,O(alkoxy) (or Ti,Cl) bonds cleave upon hydrolysis, leading to several structural forms, including oligomers. Ionic Q species with no Ti, i.e., obtained after Ti,Q cleavage, are seen for some Ti,Q derivatives by ESI-MS, which also indicates a varied nuclearity for a given species, e.g., the isolated polynuclear [Q2Ti-,-O]n has several "n" values. Mononuclear Ti complexes are obtained under rigorous anhydrous conditions. The cis structures of the mononuclear species (QT)2Ti(OCH3)2, QT = 3-methyl-4-(neopentylcarbonyl)-1-phenylpyrazol-5-onato have been analyzed with DFT methods. A trans influence is a major driving force that accounts for several sets of Ti,O bonds. One of the cis stereoisomers is 56 kcal/mol higher in energy than the other two. In contrast, all (QT)2TiCl2cis isomers show similar energies. Voltammetry of the mononuclear species (QT)2Ti(OnPr)2 and the antitumor tetranuclear compound [(QB)2Ti-,-O]4, (QB = 4-benzoyl-3-methyl-1-phenylpyrazol-5-onato) indicate that the TiIV is less prone to reduction to TiIII in the latter (Epc for the TiIV/TiIII couple is ,1.71 V and ,1.46 V versus Fc+/Fc, respectively). Potential antitumor compounds having a Ti/Q ratio of 1:1 do not disproportionate, unlike the equivalent acetylacetonato derivatives, and are water-soluble. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Family Reunification Rights of (Migrant) Union Citizens: Towards a More Liberal ApproachEUROPEAN LAW JOURNAL, Issue 5 2009Alina Tryfonidou Over the years, in the case-law of the European Court of Justice (ECJ) determining the availability of family reunification rights for migrant Member State nationals, the pendulum has swung back and forth, from a ,moderate approach' in cases such as Morson and Jhanjan (1982) and Akrich (2003), towards a more ,liberal approach' in cases such as Carpenter (2002) and Jia (2007). Under the Court's ,moderate approach', family reunification rights in the context of the Community's internal market policy are only granted in situations where this is necessary for enabling a Member State national to move between Member States in the process of exercising one of the economic fundamental freedoms; in other words, where there is a sufficient link between the exercise of one of those freedoms and the need to grant family reunification rights under EC law. Conversely, under the Court's ,liberal approach', in order for family reunification rights to be bestowed by EC law, it suffices that the situation involves the exercise of one of the market freedoms and that the claimants have a familial link which is covered by Community law; in other words, there is no need to illustrate that there is a link between the grant of such rights and the furtherance of the Community's aim of establishing an internal market. The recent judgments of the ECJ in Eind and Metock (and its order in Sahin) appear to have decidedly moved the pendulum towards the ,liberal approach' side. In this article, it will be explained that the fact that the EU is aspiring to be not only a supranational organisation with a successful and smoothly functioning market but also a polity, the citizens of which enjoy a number of basic rights which form the core of a meaningful status of Union citizenship, is the major driving force behind this move. In particular, the move towards a wholehearted adoption of the ,liberal approach' seems to have been fuelled by a desire, on the part of the Court, to respond to a number of problems arising from its ,moderate approach' and which appear to be an anomaly in a citizens' Europe. These are: a) the incongruity caused between the (new) aim of the Community of creating a meaningful status of Union citizenship and the treatment of Union citizens (under the Court's ,moderate approach') as mere factors of production; and b) the emergence of reverse discrimination. The article will conclude with an explanation of why the adoption of the Court's liberal approach does not appear to be a proper solution to these problems. [source] Genetic transduction in freshwater ecosystemsFRESHWATER BIOLOGY, Issue 6 2008OLADELE A. OGUNSEITAN Summary 1. Lateral genetic exchange is a profound consequence of the co-existence of viruses (bacteriophages) and bacteria in freshwater ecosystems. Transduction is distinct from other mechanisms of genetic exchange because it is driven by potentially lethal agents external to the donor and recipient cells. Therefore, transduction is reputed to be a major driving force behind the diversity in natural populations and communities of bacteria. 2. Both generalized transduction (where every segment of the donor's genome has equal chance of being transferred to a recipient cell) and specialized transduction (where certain donor gene sequences are transferred at higher frequencies than others based on their proximity to the integration site of the transducing bacteriophage genome) have been demonstrated for various freshwater bacteria. However, these genetic exchange events occur at frequencies that vary widely, from 10,2 to 10,10 transductants per recipient, depending on the influence of various physical, chemical and biotic environmental factors on the outcome of phage,host encounters. Methodological constraints limit the interpretation of results from early studies of transduction in freshwaters because those studies introduced exogenous organisms in microcosms and excluded, to different extents, naturally occurring environmental conditions and their variability. 3. To assist the design and extrapolation of empirical observations, mathematical models including application of Group Theory are useful to estimate boundaries of the impact of transduction in generating and maintaining microbial diversity in freshwater. These theoretical excursions generate hypotheses and questions that can only be answered through refinement of current empirical estimates of transduction frequency, polarity of gene mobilization, bacteriophage host ranges, and the influence of gradients in environmental parameters that characterize freshwater ecosystems. [source] Diel variation in surface and subsurface microbial activity along a gradient of drying in an Australian sand-bed streamFRESHWATER BIOLOGY, Issue 10 2003Cecile Claret Summary 1. Microbes play key roles in nutrient transformation and organic matter mineralisation in the hyporheic zone but their short-term responses to diel variations in discharge and temperature are unknown. Rates of microbial esterase activity were hypothesised to vary vertically and along a gradient of moisture in a drying sand-bed stream where discharge fluctuated daily in response to evapotranspiration. 2. At ,fully saturated', ,moist' and ,dry' locations in three sites along a drying Australian sand-bed stream, microbial activity at three depths (surface, 10 and 30 cm) was assessed using fluorescein diacetate hydrolysis. Samples were collected in mid-summer in the late afternoon and again at dawn to assess diel variation in hydrolytic activity at each site and depth. Data loggers tracked diel variations in temperature at each depth. 3. Hydrolytic activity was up to 10-fold greater in the surface sediments in late afternoon than at dawn in all habitats, and was correlated with surface sediment temperature. Diel differences in activity were not detected at 10 cm, although daily thermal cycles were evident at this depth. Unexpectedly, activity was marginally higher at dawn at 30 cm in all habitats, perhaps reflecting lags in temperature at that depth. 4. Overall, microbial activity declined with depth, strongly correlated with vertical trends in total organic matter and concentrations of dissolved phosphorus. Particulate organic matter, probably buried during a flood 35 days earlier, appeared largely responsible for these vertical trends. On the other hand, there was little evidence for hydrological exchange between much of the hyporheic zone and the surface stream, implying that processes in the subsurface zone of this stream are effectively isolated during baseflow in mid-summer. 5. Diel cycles of wetting and drying in the moist habitats did not enhance esterase activity relative to the dry or fully saturated habitats. Sediment moisture was not correlated with microbial activity, and mats of senescent algae appeared to inhibit water loss from surface sediments in the moist habitat. In this sand-bed stream, local diel fluctuations in water level appear to have less influence on microbial activity and mineralisation of organic matter in the sediments than occasional floods that bury leaf litter and renew many hyporheic zone functions. Subreach-scale processes seem to be the major driving force of microbial processes and nutrient cycling in this sand-bed river. [source] Role of Reduced Ionic Strength and Low pH in Gelation of Chicken Breast Muscle ProteinJOURNAL OF FOOD SCIENCE, Issue 1 2005S. Ke And ABSTRACT: Elastic gels with a high moisture content of 88% were prepared at an acidic pH and low ionic strength. The relationship among pH, ionic strength, water-holding capacity, and fold score of gels was investigated. A decrease of pH from 4.1 to 3.7 or below increased gel elasticity and significantly decreased water loss under pressure (P < 0.05). In the presence of sodium chloride, gels made at pH 3.5 to 3.7 had decreased elasticity and increased water loss under pressure. Prior freezing increased the water loss of gels under pressure. Gels made with phosphoric acid and hydrochloric acid lost less water under pressure than those made with citric acid. The percentage loss of water from cylindrical gels was inversely related to the height of the cylinders, suggesting that surface effects were involved. These results suggest that net positive charges on the protein molecules at low pH produced electrostatic repulsion, which was a major driving force for water uptake in the low-salt gels. [source] Digital soil mapping in Germany,a reviewJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2006Thorsten Behrens Abstract Digital soil mapping as a tool to generate spatial soil information provides solutions for the growing demand for high-resolution soil maps worldwide. Even in highly developed countries like Germany, digital soil mapping becomes essential due to the decreasing, time-consuming, and expensive field surveys which are no longer affordable by the soil surveys of the individual federal states. This article summarizes the present state of soil survey in Germany in terms of digitally available soil data, applied digital soil mapping, and research in the broader field of pedometrics and discusses future perspectives. Based on the geomorphologic conditions in Germany, relief is a major driving force in soil genesis. This is expressed by the digital,soil mapping research which highlights the great importance of digital terrain attributes in combination with information on parent material in soil prediction. An example of digital soil mapping using classification trees in Thuringia is given as an introduction in digital soil-class mapping based on correlations to environmental covariates within the scope of the German classification system. [source] Residual tumor cells are unique cellular targets in glioblastoma,ANNALS OF NEUROLOGY, Issue 2 2010Martin Glas MD Residual tumor cells remain beyond the margins of every glioblastoma (GBM) resection. Their resistance to postsurgical therapy is considered a major driving force of mortality, but their biology remains largely uncharacterized. In this study, residual tumor cells were derived via experimental biopsy of the resection margin after standard neurosurgery for direct comparison with samples from the routinely resected tumor tissue. In vitro analysis of proliferation, invasion, stem cell qualities, GBM-typical antigens, genotypes, and in vitro drug and irradiation challenge studies revealed these cells as unique entities. Our findings suggest a need for characterization of residual tumor cells to optimize diagnosis and treatment of GBM. ANN NEUROL 2010;68:264,269 [source] Insulating effect of coals and organic rich shales: implications for topography-driven fluid flow, heat transport, and genesis of ore deposits in the Arkoma Basin and Ozark PlateauBASIN RESEARCH, Issue 2 2002J.A. Nunn ABSTRACT Sedimentary rocks rich in organic matter, such as coal and carbonaceous shales, are characterized by remarkably low thermal conductivities in the range of 0.2,1.0 W m,1 °C,1, lower by a factor of 2 or more than other common rock types. As a result of this natural insulating effect, temperature gradients in organic rich, fine-grained sediments may become elevated even with a typical continental basal heat flow of 60 mW m,2. Underlying rocks will attain higher temperatures and higher thermal maturities than would otherwise occur. A two-dimensional finite element model of fluid flow and heat transport has been used to study the insulating effect of low thermal conductivity carbonaceous sediments in an uplifted foreland basin. Topography-driven recharge is assumed to be the major driving force for regional groundwater flow. Our model section cuts through the Arkoma Basin to Ozark Plateau and terminates near the Missouri River, west of St. Louis. Fluid inclusions, organic maturation, and fission track evidence show that large areas of upper Cambrian rocks in southern Missouri have experienced high temperatures (100,140 °C) at shallow depths (< 1.5 km). Low thermal conductivity sediments, such as coal and organic rich mudstone were deposited over the Arkoma Basin and Ozark Plateau, as well as most of the mid-continent of North America, during the Late Palaeozoic. Much of these Late Palaeozoic sediments were subsequently removed by erosion. Our model results are consistent with high temperatures (100,130 °C) in the groundwater discharge region at shallow depths (< 1.5 km) even with a typical continental basal heat flow of 60 mW m,2. Higher heat energy retention in basin sediments and underlying basement rocks prior to basin-scale fluid flow and higher rates of advective heat transport along basal aquifers owing to lower fluid viscosity (more efficient heat transport) contribute to higher temperatures in the discharge region. Thermal insulation by organic rich sediments which traps heat transported by upward fluid advection is the dominant mechanism for elevated temperatures in the discharge region. This suggests localized formation of ore deposits within a basin-scale fluid flow system may be caused by the juxtaposition of upward fluid discharge with overlying areas of insulating organic rich sediments. The additional temperature increment contributed to underlying rocks by this insulating effect may help to explain anomalous thermal maturity of the Arkoma Basin and Ozark Plateau, reducing the need to call upon excessive burial or high basal heat flow (80,100 mW m,2) in the past. After subsequent uplift and erosion remove the insulating carbonaceous layer, the model slowly returns to a normal geothermal gradient of about 30 °C km,1. [source] Gene-environment interaction and obesityNUTRITION REVIEWS, Issue 12 2008Lu Qi The epidemic of obesity has become a major public health problem. Common-form obesity is underpinned by both environmental and genetic factors. Epidemiological studies have documented that increased intakes of energy and reduced consumption of high-fiber foods, as well as sedentary lifestyle, were among the major driving forces for the epidemic of obesity. Recent genome-wide association studies have identified several genes convincingly related to obesity risk, including the fat mass and obesity associated gene and the melanocortin-4 receptor gene. Testing gene-environment interaction is a relatively new field. This article reviews recent advances in identifying the genetic and environmental risk factors (lifestyle and diet) for obesity. The evidence for gene-environment interaction, especially from observational studies and randomized intervention trials, is examined specifically. Knowledge about the interplay between genetic and environmental components may facilitate the choice of more effective and specific measures for obesity prevention based on the personalized genetic make-up. [source] A detailed look at 7 million years of genome evolution in a 439 kb contiguous sequence at the barley Hv-eIF4E locus: recombination, rearrangements and repeatsTHE PLANT JOURNAL, Issue 2 2005Thomas Wicker Summary Six overlapping BAC clones covering the Hv-eIF4E gene region in barley were sequenced in their entire length, resulting in a 439.7 kb contiguous sequence. The contig contains only two genes, Hv-eIF4E and Hv-MLL, which are located in a small gene island and more than 88% of the sequence is composed of transposable elements. A detailed analysis of the repetitive component revealed that this chromosomal region was affected by multiple major duplication and deletion events as well as the insertion of numerous transposable elements, resulting in a complete reshuffling of genomic DNA. Resolving this highly complex pattern resulted in a model unraveling evolutionary events that shaped this region over an estimated 7 million years. Duplications and deletions caused by illegitimate recombination and unequal crossing over were major driving forces in the evolution of the Hv-eIF4E region, equaling or exceeding the effects of transposable element activities. In addition to a dramatic reshuffling of the repetitive portion of the sequence, we also found evidence for important contributions of illegitimate recombination and transposable elements to the sequence organization of the gene island containing Hv-eIF4E and Hv-MLL. [source] Interrogating the production of urban space in China and Vietnam under market socialismASIA PACIFIC VIEWPOINT, Issue 2 2009Terry G. McGee Abstract This paper explores two issues. First, it focuses on the question of what is the most appropriate theoretical framework for the study of the urbanisation process in China and Vietnam over the last 30 years? It is argued that Le Fefebvre's theory of the ,production of urban space' offers the most useful approach because the political economy it adopts helps identify the major driving forces in the urbanisation process in these formerly socialist societies. The second issue involves the investigation of the differences and similarities in the urbanisation process in the two countries that are engaged in similar processes of structural economic transformation. The conclusion suggests that despite historical and cultural differences between Vietnam and China, the urbanisation process in both countries is exhibiting converging features as both countries are adopting a form of ,hybrid urbanisation' that involves a combination of socialist and market economies that does not involve an inevitable move to ,capitalism'. [source] | |||||||||||||||||||