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Crucial Factor (crucial + factor)
Selected AbstractsPareto-Improving Redistribution and Pure Public GoodsGERMAN ECONOMIC REVIEW, Issue 2 2000Richard Cornes In the pure public good model, the Nash equilibrium associated with one initial income distribution may Pareto dominate the equilibrium associated with another distribution of the same aggregate income. We explore this possibility and examine its implications for Pareto-improving policy intervention by undertaking a comparative static analysis of Pareto-improving tax-financed increases in pure public good provision. Under some circumstances, a government can engineer policies that raise public good provision while increasing the well-being of contributors and non-contributors. Crucial factors promoting this outcome involve a large number of non-contributors, a high marginal valuation for the public good by non-contributors and a large aggregate response of contributors to changes in their income. [source] Wnt signaling in hematopoiesis: Crucial factors for self-renewal, proliferation, and cell fate decisionsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2010Frank J.T. Staal Abstract A large number of studies from many different laboratories have implicated the Wnt signaling pathway in regulation of hematopoiesis. However, different inducible gain- and loss-of-function approaches yielded controversial and some times contradictory results. In this prospect we will review the current ideas on Wnt signaling in hematopoiesis and early lymphopoiesis. Reviewing this large body of knowledge let us to hypothesize that different levels of activation of the pathway, dosages of Wnt signaling required and the interference by other signals in the context of Wnt activation collectively explain these controversies. Besides differences in dosage, differences in biological function of Wnt proteins in various blood cell types also is a major factor to take into account. Our own work has shown that while in the thymus Wnt signaling provides cytokine-like, proliferative stimuli to developing thymocytes, canonical Wnt signaling in HSC regulates cell fate decisions, in particular self-renewal versus differentiation. J. Cell. Biochem. 109: 844,849, 2010. © 2010 Wiley-Liss, Inc. [source] Synthesis and Physical Chemistry of s -Tetrazines: Which Ones are Fluorescent and Why?EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 35 2009Yong-Hua Gong Abstract New fluorescent tetrazines have been prepared and their electrochemistry and fluorescence efficiency evaluated. The occurrence of fluorescence as well as the wavelength were found to be strongly dependent on the substituents, which have to be electronegative heteroatoms. This has been rationalized through a computational study that showed that the crucial factor is the nature of the HOMO, which determines the existence or not of fluorescence. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Process Chain for Tailoring the Refractive Index of Thermoplastic Optical Materials using Ceramic NanoparticlesADVANCED ENGINEERING MATERIALS, Issue 6 2005E. Ritzhaupt-Kleissl Interconnections between active optical devices like laser diodes and polymer optical fibres are a crucial factor of optical damping due to coupling losses at the interfaces. Tailoring the refractive index of thermoplastic polymers can diminish these damping losses. The use of modified thermoplastics in an injection moulding process allows a high throughput and therefore a cost effective method for manufacturing passive optical parts with improved properties. [source] On the mechanism of fatigue failure in the superlong life regime (N>107 cycles).FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 11 2000Part 1: influence of hydrogen trapped by inclusions The fracture surfaces of specimens of a heat-treated hard steel, namely Cr,Mo steel SCM435, which failed in the regime of N,=,105 to 5,×,108 cycles, were investigated by optical microscopy and scanning electron microscopy (SEM). Specimens having a longer fatigue life had a particular morphology beside the inclusion at the fracture origin. The particular morphology looked optically dark when observed by an optical microscope and it was named the optically dark area (ODA). The ODA looks a rough area when observed by SEM and atomic force microscope (AFM). The relative size of the ODA to the size of the inclusion at the fracture origin increases with increase in fatigue life. Thus, the ODA is considered to have a crucial role in the mechanism of superlong fatigue failure. It has been assumed that the ODA is made by the cyclic fatigue stress and the synergetic effect of the hydrogen which is trapped by the inclusion at the fracture origin. To verify this hypothesis, in addition to conventionally heat-treated specimens (specimen QT, i.e. quenched and tempered), specimens annealed at 300 °C in a vacuum (specimen VA) and the specimens quenched in a vacuum (specimen VQ) were prepared to remove the hydrogen trapped by inclusions. The specimens VA and VQ, had a much smaller ODA than the specimen QT. Some other evidence of the influence of hydrogen on superlong fatigue failure are also presented. Thus, it is concluded that the hydrogen trapped by inclusions is a crucial factor which causes the superlong fatigue failure of high strength steels. [source] Freshwater crayfish farming technology in the 1990s: a European and global perspectiveFISH AND FISHERIES, Issue 4 2000H.E.G. Ackefors This paper aims to describe the state of crayfish farming technology in the USA, Australia and Europe, and to discuss some of the prerequisites for this industry. Data from Europe are partly based on replies from a questionnaire sent out to scientists in all European countries. For other parts of the world, the crayfish literature has been reviewed and data from the August 2000 meeting of the International Association of Astacology are also included. Issues addressed in this review are cultivated species, production and productivity figures, production technique with regard to enclosures, reproduction and feed items, disease problems, predators, pond vegetation and water quality. Fewer than a dozen crayfish species are cultivated. The most attractive ones for culture and stocking in natural waters have been transferred to more than one continent. Pond rearing techniques predominate in all countries, and the technology required to achieve the spawning and rearing of juveniles is relatively simple. Pieces of fish, carrots and potatoes are frequent supplementary feed items; plants, cereals, pieces of meat, zooplankton and pellets are also common. Diseases are not usually a major concern, except in Europe where the American plague fungus, Aphanomyces astaci, has eradicated many European crayfish populations. Predators identified as common include insects and amphibians, as well as fishes, birds and mammals. Many water macrophytes are common in crayfish farms. These may either serve a useful function or cause problems for the crayfish farmer. Water temperature is the crucial factor for crayfish production. Water parameters such as pH and certain inorganic ion concentrations may also be of concern. Acidic waters that occur in some areas are generally detrimental to crayfish. The total yield from crayfish production from farming and fishery is in the order of 120 000,150 000 tonnes, more than four times the quantity given by FAO statistics. The largest crayfish producer is the Peoples' Republic of China, followed by the USA (70 000 and 50 000 tonnes in 1999, respectively). Of the quantity produced in the USA in 1999, about 35 000 tonnes was farmed. The yield in Europe was about 4500 tonnes in 1994, and of this quantity only 160 tonnes came from aquaculture. There are no official statistics for crayfish fishery production in Australia, but about 400 tonnes came from aquaculture in 1999. [source] Storage and mobility of black carbon in permafrost soils of the forest tundra ecotone in Northern SiberiaGLOBAL CHANGE BIOLOGY, Issue 6 2008GEORG GUGGENBERGER Abstract Boreal permafrost soils store large amounts of organic carbon (OC). Parts of this carbon (C) might be black carbon (BC) generated during vegetation fires. Rising temperature and permafrost degradation is expected to have different consequences for OC and BC, because BC is considered to be a refractory subfraction of soil organic matter. To get some insight into stocks, variability, and characteristics of BC in permafrost soils, we estimated the benzene polycarboxylic acid (BPCA) method-specific composition and storage of BC, i.e. BPCA-BC, in a 0.44 km2 -sized catchment at the forest tundra ecotone in northern Siberia. Furthermore, we assessed the BPCA-BC export with the stream draining the catchment. The catchment is composed of various landscape units with south-southwest (SSW) exposed mineral soils characterized by thick active layer or lacking permafrost, north-northeast (NNE) faced mineral soils with thin active layer, and permafrost-affected raised bogs in plateau positions showing in part thermokarst formation. There were indications of vegetation fires at all landscape units. BC was ubiquitous in the catchment soils and BPCA-BC amounted to 0.6,3.0% of OC. This corresponded to a BC storage of 22,3440 g m,2. The relative contribution of BPCA-BC to OC, as well as the absolute stocks of BPCA-BC were largest in the intact bogs with a shallow active layer followed by mineral soils of the NNE aspects. In both landscape units, a large proportion of BPCA-BC was stored within the permafrost. In contrast, mineral soils with thick active layer or lacking permafrost and organic soils subjected to thermokarst formation stored less BPCA-BC. Permafrost is, hence, not only a crucial factor in the storage of OC but also of BC. In the stream water BPCA-BC amounted on an average to 3.9% of OC, and a yearly export of 0.10 g BPCA-BC m,2 was calculated, most of it occurring during the period of snow melt with dominance of surface flow. This suggests that BC mobility in dissolved and colloidal phase is an important pathway of BC export from the catchment. Such a transport mechanism may explain the high BC concentrations found in sediments of the Arctic Ocean. [source] Numerical modeling of seismic triggering, evolution, and deposition of rapid landslides: Application to Higashi,Takezawa (2004)INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 4 2010Nikos Gerolymos Abstract A mathematical model is developed for the dynamic analysis of earthquake-triggered rapid landslides, considering two mechanically coupled systems: (a) the accelerating deformable body of the slide and (b) the rapidly deforming shear band at the base of the slide. The main body of the slide is considered as a one-phase mixture of Newtonian incompressible fluids and Coulomb solids sliding on a plane of variable inclination. The evolution of the landslide is modeled via a depth-integrated model of the Savage,Hutter type coupled with: (a) a cyclic hysteretic constitutive model of the Bouc,Wen type and (b) Voellmy's rheology for the deformation of the material within the shear band. The original shallow-water equations that govern the landslide motion are appropriately reformulated to account for inertial forces due to seismic loading, and to allow for a smooth transition between the active and the passive state. The capability of the developed model is tested against the Higashi,Takezawa landslide. Triggered by the 2004 Niigata-ken Chuetsu earthquake, the slide produced about 100m displacement of a large wedge from an originally rather mild slope. The mechanism of material softening inside the shear band responsible for the surprisingly large run-out of the landslide is described by a set of equations for grain crushing-induced pore-water pressures. The back-analysis reveals interesting patterns on the flow dynamics, and the numerical results compare well with field observations. It is shown that the mechanism of material softening is a crucial factor for the initiation and evolution of the landslide, while viscoplastic frictional resistance is a key requirement for successfully reproducing the field data. Copyright © 2009 John Wiley & Sons, Ltd. [source] Improved four-node Hellinger,Reissner elements based on skew coordinatesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2008K. Wisniewski Abstract Mixed four-node elements based on the Hellinger,Reissner (HR) functional are developed for stress representations in various coordinates, including the skew, natural and Cartesian ones. The two-field HR functional is used in the classical form and in the incremental form suitable for non-linear materials. We argue that the skew coordinates, not the natural ones, should be associated with the natural basis at the element's center. If 5- and 7-parameter stress representations are assumed in these coordinates, then, for a linear elastic case, the homogenous equilibrium equations and the stress form of compatibility equation are satisfied point-wise. Two mixed four-node elements are developed and tested: 1.An assumed stress element (HR5-S) is developed from the non-enhanced HR functional, for a 5-parameter representation of stresses, formally identical as the one used, for example, in Pian and Sumihara [Int. J. Numer. Meth. Engng 1984; 20:1685,1695], but in terms of skew coordinates. This element is very simple and uses a smaller number of parameters, but is equally accurate as the elements by Yuan et al. [Int. J. Numer. Meth. Engng 1993; 36:1747,1763] and by Piltner and Taylor [Int. J. Numer. Meth. Engng 1995; 38:1783,1808]. 2.An assumed stress/enhanced strain element (HR9) is developed from the enhanced HR functional, for a 7-parameter representation of stress and a 2-parameter enhanced assumed displacement gradient or enhanced assumed strain enhancement. Various forms of 7-parameter representations appearing in the literature are reviewed, and we prove that they are linked by a linear onto transformation. The choice of coordinates for the stress and the enhancement turns out to be the crucial factor, and four combinations of coordinates for which the element performs the best are identified. Both elements are based on the Green strain, and several numerical tests show their good accuracy, in particular, their robustness to shape distortions for coarse meshes. Two update schemes for the multipliers of modes and the incremental constitutive procedure accounting for the plane stress condition for non-linear materials are tested for large deformation problems. Copyright © 2008 John Wiley & Sons, Ltd. [source] Structure analysis of Antonovsky's sense of coherence from an epidemiological mental health survey with a brief nine-item sense of coherence scaleINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 1 2007Olav Martin Klepp Abstract Antonovsky has proposed the sense of coherence (SOC) as a crucial factor that protects against symptoms of mental disease. A central issue in research on the SOC construct is whether this is most appropriately considered as one-dimensional or three-dimensional with comprehensibility (C), manageability (Ma) and meaningfulness (Me) as separate dimensions. In this paper we address this issue by means of confirmatory factor analysis of a shortened nine-item version of Antonovsky's original 29- and 13-items Sense of Coherence Scale (SOCS-29), using epidemiological data from a mental health survey of adults in local communities (N = 1,062). In addition to analysing the internal structure of the SOC items, we examine the association between estimated factor scores and variables expected to be statistically related to SOC. Goodness-of-fit indices were very good for the three-factor model but acceptable even for the one-factor model. In the three-factor model, however, the factors were found to be very highly or, with regard to Ma and C, even perfectly correlated. Moreover, the factor scores had very similar correlations with measures of psychological wellbeing, depression and anxiety and they are also very similarly related to age (and none of them are related to gender). We therefore conclude in favour of a one-factor model. Copyright © 2006 John Wiley & Sons, Ltd. [source] Evening Light Exposure: Implications for Sleep and DepressionJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2002Geralyn M. Wallace-Guy MA OBJECTIVES: To examine whether dim illumination in the evening is a factor in sleep disturbances of aging, depression, and circadian phase advance. DESIGN: One-week continuous recordings were made to record illumination exposure and to infer 24-hour sleep patterns from wrist activity. SETTING: Recordings took place during normal home and community activities. PARTICIPANTS: Complete data of 154 postmenopausal women, mean age 66.7, were selected from a larger study of participants in the Women's Health Initiative. MEASUREMENTS: Illumination in lux was averaged for 4 hours before bedtime and over 24 hours. Mood was measured using a brief eight-item screen. RESULTS: Illumination in the 4 hours before bedtime was quite dim: median 24 lux. Nevertheless, evening light exposure was not significantly related to sleep amount (in bed or out of bed) sleep efficiency, sleep latency, wake within sleep, or mood. In contrast, the overall amount of light throughout the 24 hours was negatively correlated with sleep latency, wake within sleep, and depressed mood. CONCLUSIONS: Low evening lighting does not appear to be a crucial factor in sleep and mood disturbances of aging, but overall lighting may contribute to these disturbances. [source] Gel Strengthening Effect of Wood Extract on Surimi Produced from Mackerel Stored in IceJOURNAL OF FOOD SCIENCE, Issue 8 2009A.K. Balange ABSTRACT:, The effect of ethanolic kiam wood extract (EKWE) and commercial tannin (CT) on the gel properties of surimi produced from mackerel (Rastrelliger kanagurta) stored in ice for different times (0 to 12 d) was studied. During 12 d of iced storage, pH, total volatile base (TVB), trimethylamine (TMA), and trichloroacetic acid (TCA)-soluble peptide contents as well as thiobarbituric acid-reactive substances (TBARS) of mackerel mince increased while myosin heavy chain (MHC) band intensity decreased continuously (P,< 0.05). The result suggested that deterioration, protein degradation, and lipid oxidation proceeded with increasing storage time. For corresponding surimi, TVB and TMA were almost removed and TBARS and TCA soluble peptide contents were decreased. Conversely, MHC became more concentrated. Decreases in gel-forming ability of surimi were observed when fish used as raw material were stored in ice for a longer time, regardless of EKWE or CT addition. Whiteness of surimi gel decreased and expressible moisture increased especially when the storage time increased. However, superior breaking force and deformation of surimi gel with 0.15% EKWE or 0.30% CT added, compared to those of the control gel were observed during the first 6 d of the storage. Thereafter, EKWE and CT had no gel enhancing effect on surimi. Therefore, freshness was a crucial factor determining gel enhancing ability of EKWE or CT toward mackerel surimi. [source] Yélî Dnye and the Theory of Basic Color TermsJOURNAL OF LINGUISTIC ANTHROPOLOGY, Issue 1 2000Stephen C. Levinson The theory of basic color terms was a crucial factor in the demise of linguistic relativity. The theory is now once again under scrutiny and fundamental revision. This article details a case study that undermines one of the central claims of the classical theory, namely that languages universally treat color as a unitary domain, to be exhaustively named. Taken together with other cases, the study suggests that a number of languages have only an incipient color terminology, raising doubts about the linguistic universality of such terminology. [source] Pricing Behavior and the Response of Hours to Productivity ShocksJOURNAL OF MONEY, CREDIT AND BANKING, Issue 7 2007DOMENICO J. MARCHETTI pricing behavior; technology shocks; hours Recent contributions have suggested that technology shocks have a negative impact on hours, contrary to the prediction of standard flexible-price models of the business cycle. Some authors have interpreted this finding as evidence in favor of sticky-price models, while others have either extended flexible-price models or disputed the empirical finding itself. In this paper, we estimate a variety of alternative total factor productivity measures for a representative sample of Italian manufacturing firms and on average find a negative effect of productivity shocks on hours growth. More interestingly, using the reported frequency of price reviews, we show that the contractionary effect is stronger for firms with stickier prices and weaker or not significant for firms with more flexible prices. Price stickiness remains a crucial factor in shaping the response of hours after controlling for product storability or market power. [source] Pharmacokinetic aspects of biotechnology productsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2004Lisa Tang Abstract In recent years, biotechnologically derived peptide and protein-based drugs have developed into mainstream therapeutic agents. Peptide and protein drugs now constitute a substantial portion of the compounds under preclinical and clinical development in the global pharmaceutical industry. Pharmacokinetic and exposure/response evaluations for peptide and protein therapeutics are frequently complicated by their similarity to endogenous peptides and proteins as well as protein nutrients. The first challenge frequently comes from a lack of sophistication in various analytical techniques for the quantification of peptide and protein drugs in biological matrices. However, advancements in bioassays and immunoassays,along with a newer generation of mass spectrometry-based techniques,can often provide capabilities for both efficient and reliable detection. Selection of the most appropriate route of administration for biotech drugs requires comprehensive knowledge of their absorption characteristics beyond physicochemical properties, including chemical and metabolic stability at the absorption site, immunoreactivity, passage through biomembranes, and active uptake and exsorption processes. Various distribution properties dictate whether peptide and protein therapeutics can reach optimum target site exposure to exert the intended pharmacological response. This poses a potential problem, especially for large protein drugs, with their typically limited distribution space. Binding phenomena and receptor-mediated cellular uptake may further complicate this issue. Elimination processes,a critical determinant for the drug's systemic exposure,may follow a combination of numerous pathways, including renal and hepatic metabolism routes as well as generalized proteolysis and receptor-mediated endocytosis. Pharmacokinetic/pharmacodynamic (PK/PD) correlations for peptide and protein-based drugs are frequently convoluted by their close interaction with endogenous substances and physiologic regulatory feedback mechanisms. Extensive use of pharmacokinetic and exposure/response concepts in all phases of drug development has in the past been identified as a crucial factor for the success of a scientifically driven, evidence-based, and thus accelerated drug development process. Thus, PK/PD concepts are likely to continue and expand their role as a fundamental factor in the successful development of biotechnologically derived drug products in the future. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:2184,2204, 2004 [source] The Idea of LiteracyJOURNAL OF PHILOSOPHY OF EDUCATION, Issue 2 2000Jim MacKenzie In this paper I show that literacy is not, as is often thought, a necessary condition for civilisation; argue that it was not, as often thought, the crucial factor in enabling the modern world to emerge from earlier civilisations; report the disadvantages of literacy as expressed by Plato's character Socrates and Milne's character Piglet, and look at the relation of literacy to reasoning and to philosophy; trace the role of the idea of literacy in the nineteenth century protocol for creating national cultures, and speculate on further developments in the same line; and then discuss its role in the modern economy and in the future. [source] Developing Good Practice in the Clinical Assessment of People With Profound Intellectual Disabilities and Multiple ImpairmentJOURNAL OF POLICY AND PRACTICE IN INTELLECTUAL DISABILITIES, Issue 2 2007Steve Carnaby Abstract, The task of assessing people with profound intellectual disabilities and multiple impairments can be a daunting one, for experienced and newly qualified clinicians and practitioners alike. Difficulties with definitions in the context of challenging, excluding service delivery models can sometimes lead to incoherent and inconsistent approaches. The author examines a number of issues, including the paucity of adequately sensitive, standardized assessment tools, the importance of collaborative working, and the acknowledgment that services can be ill-equipped to face the challenges presented by people with such complex and chronic support needs. The role of an overly generic service philosophy in potentially limiting the work of clinicians is noted, and the author notes that evaluating development is a crucial factor in any overall assessment. The author concludes with a number of recommendations for developing good practice in this crucial area of the support process, including: agree on terminology and inclusion criteria; take a transdisciplinary approach; use a developmental model; consider the impact of neurological conditions; select measures and informants carefully; and consider the assessment as an intervention. [source] A Solvent Free Graft Copolymerization of Maleic Anhydride onto Cellulose Acetate Butyrate Bioplastic by Reactive ExtrusionMACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2006Arief C. Wibowo Abstract Summary: Interfacial adhesion between fibers and matrix is a crucial factor for effective stress transfer from matrix to fiber; especially in short fiber reinforced composite systems. The use of a chemical compatibilizer is an efficient means to achieve such adhesion. Maleic anhydride-grafted-cellulose acetate butyrate (CAB-g-MA) is one such compatibilizer which can be used in biocomposite fabrication, and this has been synthesized in our laboratory by utilizing a twin-screw reactive extrusion process in the presence of a free radical initiator (2,5-dimethyl-2,5-di(tert -butylperoxy)hexane). The unique feature of this process is its solvent-free approach for grafting of maleic anhydride onto CAB, without hydroxyl group protection. CAB-g-MA was characterized using FTIR as well as by a non-aqueous titration method. The effects of initiator and monomer concentrations and various processing conditions on the graft content were also investigated. The preliminary results show that by adding approximately 10 wt.-% of CAB-g-MA into a plasticized cellulose acetate butyrate (TEB)-industrial hemp fiber biocomposites system, an improvement in tensile strength (20%) and in tensile modulus (45%) were obtained. These results are promising in that they pave the way for future studies involving the use of CAB-g-MA as a suitable compatibilizer for cellulose ester-natural fiber biocomposites. [source] Extreme sex-biased dispersal in the communally breeding, nonmigratory Bechstein's bat (Myotis bechsteinii)MOLECULAR ECOLOGY, Issue 8 2002G. Kerth Abstract Maternity colonies of the communally breeding, nonmigratory Bechstein's bat consist of closely related females that live together with unrelated females, and average colony relatedness is low despite the absence of immigration. We compared the genetic structure of both nuclear and mitochondrial microsatellites in order to quantify sex-specific dispersal rates. More specifically, we aimed at testing whether male dispersal is able to balance the genetic effect of strong (absolute) female philopatry. Absolute female philopatry, indicated by an extreme mitochondrial DNA population differentiation of 96%, was indeed opposed by strong (possibly complete) male dispersal. Based on our knowledge of the biology of Myotis bechsteinii, we conclude that inbreeding avoidance is likely to be the crucial factor driving male dispersal in this species. [source] Kell and XK immunohistochemistry in McLeod myopathyMUSCLE AND NERVE, Issue 10 2001Hans H. Jung MD Abstract The McLeod syndrome is an X-linked neuroacanthocytosis manifesting with myopathy and progressive chorea. It is caused by mutations of the XK gene encoding the XK protein, a putative membrane transport protein of yet unknown function. In erythroid tissues, XK forms a functional complex with the Kell glycoprotein. Here, we present an immunohistochemical study in skeletal muscle of normal controls and a McLeod patient with a XK gene point mutation (C977T) using affinity-purified antibodies against XK and Kell proteins. Histological examination of the affected muscle revealed the typical pattern of McLeod myopathy including type 2 fiber atrophy. In control muscles, Kell immunohistochemistry stained sarcoplasmic membranes. XK immunohistochemistry resulted in a type 2 fiber-specific intracellular staining that was most probably confined to the sarcoplasmic reticulum. In contrast, there was only a weak background signal without a specific staining pattern for XK and Kell in the McLeod muscle. Our results demonstrate that the lack of physiological XK expression correlates to the type 2 fiber atrophy in McLeod myopathy, and suggest that the XK protein represents a crucial factor for the maintenance of normal muscle structure and function. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1346,1351, 2001 [source] Death comes early: apoptosis observed in ENS precursorsNEUROGASTROENTEROLOGY & MOTILITY, Issue 7 2009H. Enomoto Abstract, Cell death is a physiological and fundamental process in normal organogenesis. During the development of the nervous system, cell death or apoptosis occurs in early and late developmental time periods, affecting neural precursors and neurons respectively. In the development of the enteric nervous system (ENS), however, apoptosis of neurons has not been detected, a feature unique to enteric neurons. In this issue of Neurogastroenterology and Motility, Wallace et al. focused on an early phase of ENS development and identified apoptotic cell death in vagal neural crest cells, the primary cellular source for the ENS. Introduction of an antiapoptotic molecule in the vagal neural crest and its derivatives resulted in the overproduction of neurons in the foregut. Thus, unlike the neurons themselves, ENS precursors do undergo apoptosis, which may, by regulating the size of the ENS precursor pool, be a crucial factor in determining the final cell number in the ENS. [source] Unusual evolution of an Epstein,Barr virus-associated leiomyosarcoma occurring after liver transplantationPEDIATRIC TRANSPLANTATION, Issue 5 2001Bénédicte Brichard Abstract: We report the case of a child who developed, 2 yr after orthotopic liver transplantation (OLTx) for biliary atresia, a multi-focal hepatic tumor with lymphonodular metastases, identified as an Epstein,Barr virus (EBV)-associated leiomyosarcoma. Chemotherapy was given without tumor response. Subsequently, slow growth of the tumor was observed. Immunosuppression was tapered and stopped 9 yr after transplantation. At the present time, 12 yr after the discovery of the first hepatic lesions, the patient is alive and completely symptom-free, the abdominal masses are stable, and liver function tests are completely normal. Smooth muscle tumors are increasingly recognized in children with various immunodeficiencies occurring after organ transplantation. This unusual evolution of a clinically aggressive tumor into a stable disease after restoration of immunity confirms that the immune status of the patient is a crucial factor. [source] Spatial and temporal variation in the fruiting phenology of palms in isolated standsPLANT SPECIES BIOLOGY, Issue 1 2008GREGORY H. ADLER Abstract Fruiting phenologies of two species of palms, Astrocaryum standleyanum L. H. Bailey and Attalea butyracea (Mutis ex L. f) Wess. Boer, isolated on eight small (1.7,3.7 ha) forested islands in the Panama Canal were studied over a 33-month period. Individual palms were permanently marked with numbered aluminum tags and censused each month for the presence of ripe fruits. The dataset consisted of 1106 monthly observations of palms with ripe fruits among the 634 marked individuals. Mean densities of palms of reproductive size varied widely among islands, ranging from a low of 0.3 ha,1 for A. standleyanum and 3.5 ha,1 for A. butyracea to a high of 44.9 ha,1 for A. standleyanum and 33.7 ha,1 for A. butyracea. Both species showed distinctly seasonal periods of fruiting activity that varied in duration between the two species and among years. The timing of fruiting by A. standleyanum was highly synchronous among islands, whereas inter-island synchrony in A. butyracea was less pronounced. The percentages of marked individuals that fruited varied widely among islands and years. Results indicated that these palms responded to both spatially and temporally variable conditions that promoted fruit production. We suggest that pollinator abundances are a crucial factor affecting reproductive output. Conditions that favor successful reproduction and seed dispersal, such as pollinator activity and the attraction of dispersal agents, may be the ultimate factors that have influenced the reproductive phenologies of these two species of palms. [source] Elucidation of the solution structure of cardiotoxin analogue V from the Taiwan cobra (Naja naja atra),Identification of structural features important for the lethal action of snake venom cardiotoxinsPROTEIN SCIENCE, Issue 4 2000Gurunathan Jayaraman Abstract The aim of the present study is to understand the structural features responsible for the lethal activity of snake venom cardiotoxins. Comparison of the lethal potency of the five cardiotoxin isoforms isolated from the venom of Taiwan cobra (Naja naja atra) reveals that the lethal potency of CTX I and CTX V are about twice of that exhibited by CTX II, CTX III, and CTX IV. In the present study, the solution structure of CTX V has been determined at high resolution using multidimensional proton NMR spectroscopy and dynamical simulated annealing techniques. Comparison of the high resolution solution structures of CTX V with that of CTX IV reveals that the secondary structural elements in both the toxin isoforms consist of a triple and double-stranded antiparallel ,-sheet domains. Critical examination of the threedimensional structure of CTX V shows that the residues at the tip of Loop III form a distinct "finger-shaped" projection comprising of nonpolar residues. The occurrence of the nonpolar "finger-shaped" projection leads to the formation of a prominent cleft between the residues located at the tip of Loops II and III. Interestingly, the occurrence of a backbone hydrogen bonding (Val27CO to Leu48NH) in CTX IV is found to distort the "finger-shaped" projection and consequently diminish the cleft formation at the tip of Loops II and III. Comparison of the solution structures and lethal potencies of other cardiotoxin isoforms isolated from the Taiwan cobra (Naja naja atra) venom shows that a strong correlation exists between the lethal potency and occurrence of the nonpolar "finger-shaped" projection at the tip of Loop III. Critical analysis of the structures of the various CTX isoforms from the Taiwan cobra suggest that the degree of exposure of the cationic charge (to the solvent) contributed by the invariant lysine residue at position 44 on the convex side of the CTX molecules could be another crucial factor governing their lethal potency. [source] Nurturing knowledge: the UK Higher Education Links scheme,PUBLIC ADMINISTRATION & DEVELOPMENT, Issue 2 2003Derek A. Eldridge This article examines the development of academic networks and expertise through the UK Higher Education Links scheme, which is funded by the UK Department for International Development, managed by the British Council and supported by the principals of UK higher education institutions. The links are established between UK and overseas universities primarily to enhance research and/or teaching capacity, with the ultimate aim of alleviating poverty and promoting sustainable development. This article draws on data gathered for a large-scale, multiple-method evaluation which endorsed the scheme's continuation. It is argued that a crucial factor helping to make individual links a success was good relationships between respective co-ordinators, although the nature of these relationships varied. The article discusses the extent to which the formation of fruitful academic networks and partnerships enabling knowledge transfer were encouraged. Copyright © 2003 John Wiley & Sons, Ltd. [source] Wealth Distributions of Migrant and Australian-born Households,THE ECONOMIC RECORD, Issue 268 2009DENISE DOIRON Wealth is an important measure of overall economic well-being and a crucial factor in migrants' ability to integrate into their new country. Using data from the 2002 HILDA survey, this study explores the disparity between the wealth distributions of native-born and foreign-born households in Australia. Using quantile regressions the results reveal that migrants have significantly less wealth than their Australian-born counterparts throughout the wealth distribution. This is despite the greater wealth-generating characteristics of the foreign-born. The wealth differentials are reduced but still negative for the migrant cohorts who have been in Australia for over 25 years. [source] Regulating p73 isoforms in human tumoursTHE JOURNAL OF PATHOLOGY, Issue 4 2006PJ Coates Abstract Although mutations in the TP73 gene are extremely rare in human tumours, altered expression is common. In some tumours, most notably leukaemias and lymphomas, expression of TP73 is reduced, suggesting a tumour suppressor role. In contrast, TP73 is over-expressed in many other tumour types, implying that it has oncogenic functions in human tumourigenesis. These conflicting scenarios can be reconciled by the observations that the TP73 gene produces p53-like isoforms (TAp73) and anti-p53 isoforms (,TAp73). Thus, loss of TAp73 or over-expression of ,TAp73 should each promote oncogenic transformation, and the balance of expression of the opposing isoforms is the crucial factor. The mechanisms that regulate expression of TP73 isoforms are therefore of great interest. Recent data provide evidence for interacting roles of ZEB1, p300, and a polymorphic 73 bp deletion in intron 1 of the human TP73 gene in this process. Importantly, alterations to the proposed regulatory pathway for controlling TP73 isoform expression in colorectal cancer are associated with adverse clinico-pathological characteristics. Because p73 is also associated with tumour chemosensitivity, these new findings should provide prognostic information and have the potential to guide future therapeutic decisions. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Recruiting and Retaining Physicians in Very Rural AreasTHE JOURNAL OF RURAL HEALTH, Issue 2 2010Carolyn M. Pepper PhD Abstract Context: Recruiting and retaining physicians is a challenge in rural areas. Growing up in a rural area and completing medical training in a rural area have been shown to predict decisions to practice in rural areas. Little is known, though, about factors that contribute to physicians' decisions to locate in very sparsely populated areas. Purpose: In this study, we investigated whether variables associated with rural background and training predicted physicians' decisions to practice in very rural areas. We also examined reasons given for plans to leave the study state. Methods: Physicians in the State of Wyoming (N = 693) completed a questionnaire assessing their background, current practice, and future practice plans. Findings: Being raised in a rural area and training in nearby states predicted practicing in very rural areas. High malpractice insurance rates predicted planning to move one's practice out of state rather than within state. Conclusions: Rural backgrounds and training independently predict practice location decisions, but high malpractice rates are the most crucial factor in future plans to leave the state. [source] Influence of motility and vitality in intracytoplasmic sperm injection with ejaculated and testicular spermANDROLOGIA, Issue 4 2005T. Stalf Summary The vitality of spermatozoa used for intracytoplasmic sperm injection (ICSI) is a crucial factor for fertilization, establishment and outcome of a pregnancy in assisted reproductive technique cycles. The sperm origin may also be a limiting factor, although little is known about this issue. It is known that the motility of injected spermatozoa and their origin from ejaculate or testicular biopsies are important predictors in terms of fertilization, pregnancy and birth rates. Oocytes of patients in 2593 cycles were retrieved in our in vitro fertilization programme and inseminated via ICSI. We used motile (group 1, n = 2317) or immotile ejaculated spermatozoa (group 2, n = 79), motile sperm retrieved from testicular biopsies (group 3, n = 62) and immotile spermatozoa from testicular biopsies (group 4, n = 135). Female age and number of oocytes retrieved did not differ significantly among the groups. The fertilization rates were as follows: 67.1% in group 1, 49.8% in group 2, 68.3% in group 3 and 47.8% in group 4. The pregnancy rates in cases where three embryos had been transferred amounted to 35.7% in group 1, 17.3% in group 2, 38.3% in group 3 and 20.5% in group 4. The embryo quality showed no differences between groups 1 and 3 (14.5), and between groups 2 (11.8) and 4 (10.8). The abortion rate was similar in groups 1,3, but increased in group 4 (26.6%, 27.3%, 31.6% and 55.5%). Irrespective of their origin, the fertilization potential of injected spermatozoa was found to be influenced by motility. The resulting pregnancy and birth rates, i.e. the potential of the resulting embryos to implant and to achieve viable pregnancies, seem to be additionally dependent on the sperm origin. This was well shown by declining rates when spermatozoa in a relatively early stage of maturity had been used. We see increasing evidence that the degree of sperm maturity has an important impact on the outcome of ICSI. In obstructive azoospermia, spermatozoa retrieved from the epididymis should be used rather than testicular biopsy spermatozoa, or testicular sperm should be preincubated in culture medium before ICSI. [source] Regulation of uterine function by cytokines in cows: Possible actions of tumor necrosis factor-,, interleukin-1, and interferon-,ANIMAL SCIENCE JOURNAL, Issue 3 2006Kiyoshi OKUDA ABSTRACT When animals do not become pregnant, regression of the corpus luteum (CL) is essential for normal cyclicity because it allows the development of a new ovulatory follicle. Luteal regression is caused by a pulsatile release of prostaglandin (PG) F2, from the uterus in the late luteal phase in most mammals including cattle. Although it has been proposed in ruminants that pulsatile PGF2, secretion is generated by a positive feedback loop between luteal and/or hypophyseal oxytocin and uterine PGF2,, the bovine endometrium may possess other mechanisms for initiation of luteolytic PGF2, secretion. There is increasing evidence that several cytokines mainly produced by immune cells modulate CL and uterine function in many species. Tumor necrosis factor-, (TNF-,) stimulates PGF2, output from bovine endometrium not only at the follicular phase but also at the late luteal phase. Administration of TNF-, at a high concentration prolongs luteal lifespan, whereas administration of a low concentration of TNF-, accelerates luteal regression in cows. The data obtained from the authors' previous in vitro and in vivo studies strongly suggest that TNF-, is a crucial factor in regulating luteolysis in cows. The authors' recent study has shown that interleukin-1, mediates PG secretion from bovine endometrium as a local regulator. Furthermore, interferon-, (IFN-,) suppresses the action of TNF-, on PGF2, synthesis by the bovine endometrium in vitro, suggesting that IFN-, plays a luteoprotective role by inhibiting TNF-,-induced PGF2, production in early pregnancy. The purpose of the present review is to summarize current understanding of the endocrine mechanisms that regulate uterine function by cytokines during the estrous cycle and early pregnancy in cows. [source] | |||||||||||||||||||||||||||||||