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Increased Size (increased + size)
Selected AbstractsHistopathological alterations in the edible snail, Babylonia areolata (spotted babylon), in acute and subchronic cadmium poisoningENVIRONMENTAL TOXICOLOGY, Issue 2 2005P. Tanhan Abstract Histopathological alterations in 6- to 8-month-old juvenile spotted babylon, Babylonia areolata, from acute and subchronic cadmium exposure were studied by light microscopy. The 96-h LC50 value of cadmium for B. areolata was found to be 3.35 mg/L, and the maximum acceptable toxicant concentration (MATC) was 1.6 mg/L. Snails were exposed to 3.35 and 0.08 mg/L (5% of MATC) of cadmium for 96 h and 90 days, respectively. After exposure the gill, the organs of the digestive system (proboscis, esophagus, stomach, digestive gland, and rectum), and the foot were analyzed for cadmium accumulation. The results showed that most digestive organs had a high affinity for cadmium. The main target organ was the stomach, which could accumulate on average 1192.18 ,g/g dry weight of cadmium. Cadmium was shown to accumulate to a lesser extent in the digestive gland, gill, rectum, esophagus, proboscis, and foot. Histopathological alterations were observed in the gill and digestive organs (proboscis, esophagus, stomach, and rectum). The study showed that the stomach and gill were the primary target organs of both acute and subchronic exposure. Gill alterations included increased size of mucous vacuoles, reduced length of cilia, dilation and pyknosis of nuclei, thickening of basal lamina, and accumulation of hemocytes. The epithelial lining of the digestive tract showed similar alterations such as increased size of mucous vacuoles, reduced length of cilia, and dilation of nuclei. In addition, fragmentation of the muscle sheath was observed. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 142,149, 2005. [source] RAPID GROWTH RESULTS IN INCREASED SUSCEPTIBILITY TO PREDATION IN MENIDIA MENIDIAEVOLUTION, Issue 9 2003Stephan B. Munch Abstract Several recent studies have demonstrated that rapid growth early in life leads to decreased physiological performance. Nearly all involved experiments over short time periods (<1 day) to control for potentially confounding effects of size. This approach, however, neglects the benefits an individual accrues by growing. The net effect of growth can only be evaluated over a longer interval in which rapidly growing individuals are allowed the time required to attain the expected benefits of large size. We used two populations of Menidia menidia with disparate intrinsic growth rates to address this issue. We compared growth and survivorship among populations subject to predation in mesocosms under ambient light and temperature conditions for a period of up to 30 days to address two questions: Do the growth rates of fish in these populations respond differently to the presence of predators? Is the previously demonstrated survival cost of growth counterbalanced by the benefits of increased size? We found that growth was insensitive to predation risk: neither population appeared to modify growth rates in response to predation levels. Moreover, the fast-growing population suffered significantly higher mortality throughout the trials despite being 40% larger than the slow-growing population at the experiment's end. These results confirm that the costs of rapid growth extend over prolonged intervals and are not ameliorated merely by the attainment of large size. [source] Enhanced Charge Transportation in Semiconducting Polymer/Insulating Polymer Composites: The Role of an Interpenetrating Bulk InterfaceADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Guanghao Lu Abstract The charge transportation in poly(3-butylthiophene) (P3BT)/insulating polymer composites is studied both microscopically and macroscopically. The increased mobility of free charge carriers, in particular hole mobility, contributes to the enhanced electrical conductivity of this semiconductor/insulator composite. The conductivity origin of the composite, as revealed by conductive-atomic force microscopy (C-AFM), comes mainly from the P3BT network, whose carrier mobility has been improved as a result of reduced activation energy for charge transportation upon forming an interface with the insulating matrix. Both the huge interfacial area and interconnected conductive component are morphologically required for the enhanced electrical property of the composite. An increased size of the P3BT domains, which correspondingly reduces the interfacial area between the two components, ruins the enhancement. This study clarifies the mechanism of the higher electrical properties achieved in a semiconducting polymer upon blending with an insulating polymer, which will further promote the development of these low-cost, easily processable, and environmentally stable composites. [source] Policy analysis for tropical marine reserves: challenges and directionsFISH AND FISHERIES, Issue 1 2003Murray A Rudd Abstract Marine reserves are considered to be a central tool for marine ecosystem-based management in tropical inshore fisheries. The arguments supporting marine reserves are often based on both the nonmarket values of ecological amenities marine reserves provide and the pragmatic cost-saving advantages relating to reserve monitoring and enforcement. Marine reserves are, however, only one of a suite of possible policy options that might be used to achieve conservation and fisheries management objectives, and have rarely been the focus of rigorous policy analyses that consider a full range of economic costs and benefits, including the transaction costs of management. If credible analyses are not undertaken, there is a danger that current enthusiasm for marine reserves may wane as economic performance fails to meet presumed potential. Fully accounting for the value of ecological services flowing from marine reserves requires consideration of increased size and abundance of focal species within reserve boundaries, emigration of target species from reserves to adjacent fishing grounds, changes in ecological resilience, and behavioural responses of fishers to spatially explicit closures. Expanding policy assessments beyond standard cost,benefit analysis (CBA) also requires considering the impact of social capital on the costs of managing fisheries. In the short term, the amount of social capital that communities possess and the capacity of the state to support the rights of individuals and communities will affect the relative efficiency of marine reserves. Reserves may be the most efficient policy option when both community and state capacity is high, but may not be when one and/or the other is weak. In the longer term, the level of social capital that a society possesses and the level of uncertainty in ecological and social systems will also impact the appropriate level of devolution or decentralization of fisheries governance. Determining the proper balance of the state and the community in tropical fisheries governance will require broad comparative studies of marine reserves and alternative policy tools. [source] Modernizing UK health services: ,short-sharp-shock' reform, the NHS subsistence economy, and the spectre of health care famineJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2005Bruce G. Charlton MD Abstract Modernization is the trend for societies to grow functionally more complex, efficient and productive. Modernization usually occurs by increased specialization of function (e.g. division of labour, such as the proliferation of specialists, in, medicine),, combined, with, increased, organization, in, order to co-ordinate the numerous specialized functions (e.g. the increased size of hospitals and specialist teams, including the management of these large groups). There have been many attempts to modernize the National Health Service (NHS) over recent decades, but it seems that none have significantly enhanced either the efficiency or output of the health care system. The reason may be that reforms have been applied as a ,drip-drip' of central regulation, with the consequence that health care has become increasingly dominated by the political system. In contrast, a ,short-sharp-shock' of radical and rapid modernization seems to be a more successful strategy for reforming social systems , in-between waves of structural change the system is left to re-orientate towards its client group. An example was the Flexner-initiated reform of US medical education which resulted in the closure of nearly half the medical colleges, an immediate enhancement in quality and efficiency of the system and future growth based on best institutional practices. However, short-sharp-shock reforms would probably initiate an NHS ,health care famine' with acute shortages and a health care crisis, because the NHS constitutes a ,subsistence economy' without any significant surplus of health services. The UK health care system must grow to generate a surplus before it can adequately be modernized. Efficient and rapid growth in health services could most easily be generated by stimulating provision outside the NHS, using mainly staff trained abroad and needs-subsidized ,item-of-service'-type payment schemes. Once there is a surplus of critically vital health services (e.g. acute and emergency provision), then radical modernization should rapidly improve the health service by a cull of low-quality and inefficient health care providers. [source] Differential Expression of Vasoactive Intestinal Polypeptide Receptor 1 and 2 mRNA in Murine Intestinal T Lymphocyte SubtypesJOURNAL OF NEUROENDOCRINOLOGY, Issue 9 2001B.-F. Qian Abstract Neuropeptides may exert a variety of effects on the immune cells at both systemic and mucosal immune sites. The immunoregulatory properties refer to the ability of physiological signals and pathways to influence various immune functions. Vasoactive intestinal polypeptide (VIP), a neuropeptide present in high concentration in gut, was studied for its production and receptor expression in intraepithelial and lamina propria T lymphocytes of mouse intestine. Using reverse transcription-polymerase chain reaction (RT-PCR) analysis, it was demonstrated that VIP receptor 1 (VIPR1) was constantly expressed in intraepithelial and lamina propria T lymphocytes from both small and large intestine. In contrast, VIPR2 was identified only in T cells from small intestine. Further studies on purified subpopulations of T lymphocytes indicated the existence of VIPR2 in CD8+ T cells, but not CD4+ and CD4CD8 double negative T cells, although all these three subpopulations displayed VIPR1. In addition, VIPR1 mRNA was detected in splenic T lymphocytes, but no signal was obtained for VIPR2 mRNA, even after stimulation of the cells with anti-CD3,-chain mAb, phorbol 12-myristate 13-acetate (PMA) and/or VIP. The presence of VIP receptor(s) on intestinal T lymphocytes was supported by the detection of VIP on the cell surface using dual colour immunoflowcytometry. In-vitro treatment with VIP resulted in a tendency towards an increased size of the VIP immunoreactive T cell population and significantly enhanced the average immunofluorescence intensity of the surface labelling. This indicates that the receptors are partially occupied by locally produced VIP in vivo and that more peptide molecules can be bound on the lymphocytes when needed, released and accumulated in higher concentration at the action sites. We failed to detect the expression of VIP mRNA in T lymphocytes, from either intestine or spleen. These observations support that VIP may be an important immune modulator in gut acting through specific receptors on T lymphocytes. The differential mRNA expression of VIP receptor subtypes in cells with different phenotypes and in different immune compartments may suggest diverse regulatory roles of the neuropeptide in immune responses. [source] Proplatelet formation in heterozygous Bernard-Soulier syndrome type BolzanoJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 3 2009A. BALDUINI Summary.,Background: Although mutations of GPIb, are among the most frequent causes of inherited platelet disorders, the mechanisms for the onset of thrombocytopenia and platelet macrocytosis are still poorly defined. Objective: In this work we analyzed in vitro megakaryocyte differentiation and proplatelet formation in six subjects heterozygous for the Ala156Val mutation in the GPIb, (Bolzano mutation). Methods: Human megakaryocytes were obtained by differentiation of patient cord blood-derived CD34+ cells and peripheral blood-derived CD45+ cells. Proplatelet formation was evaluated by phase contrast and fluorescence microscopy. Results: Megakaryocyte differentiation from both cord blood (one patient) and peripheral blood (five patients) was comparable to controls. However, proplatelet formation was reduced by about 50% with respect to controls. An identical defect of proplatelet formation was observed when megakaryocytes were plated on fibrinogen, von Willebrand factor or grown in suspension. Morphological evaluation of proplatelet formation revealed an increased size of proplatelet tips, which was consistent with the increased diameters of patients' blood platelets. Moreover, ,-tubulin distribution within proplatelets was severely deranged. Conclusions: Megakaryocytes from patients carrying a Bolzano allele of GPIb, display both quantitative and qualitative abnormalities of proplatelet formation in vitro. These results suggest that a defect of platelet formation contributes to macrothrombocytopenia associated to the Bolzano mutation, and indicate a key role for GPIb, in proplatelet formation. [source] Risk reduction and real estate portfolio sizeMANAGERIAL AND DECISION ECONOMICS, Issue 7 2001Peter J. Byrne There is remarkably little empirical evidence of the advantages of increased size on risk levels in real estate portfolios based on actual portfolios. This paper improves this by examining the portfolio risk of a large sample of actual real estate data in the UK over the period from 1981 to 1996. The results show that real estate portfolios of larger sizes tend, on average, to have lower risks than smaller sized portfolios and, more importantly, that portfolios with only a few assets can have very high or very low risk. For fund managers to be confident that their portfolio will have a risk level like the average, they need to hold portfolios of a considerably greater size than they might expect, or can sensibly acquire. Previous studies suggesting that only 20,40 properties are needed to reduce the risk of a property portfolio down to the market level are a significant underestimate. The actual figure is likely to be 400,500 properties, well above that of even the largest fund in the UK. Size alone does not necessarily lead to a reduction in portfolio risk. Other factors are of greater importance. Copyright © 2001 John Wiley & Sons, Ltd. [source] Temperature Effect on the Fluroescence Anisotropy Decay Dynamics of Coumarin-153 Dye in Triton-X-100 and Brij-35 Miscellar Solutions,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2005Manoj Kumbhakar ABSTRACT The fluorescence anisotropy decay dynamics of the fluorescent probe Coumarin-153 (C153) have been investigated in two neutral micelles, Triton-X-100 (TX-100) and Brij-35 (BJ-39, at different temperatures and analyzed on the basis of the wellknown two-step model. Because steady-state fluorescence spectra of the above probe do not show any noticeable changes with respect to temperature, for either of the studied micelles, suggests a similar polarity in the microenvironment around the probe at all the temperatures studied. The anisotropy results indicated that, for both the micelles, the fluidity inside the Palisade layer increases with temperature. However, the temperature effect on the anisotropy decay is relatively more pronounced in TX-100 than in BJ-35. It is inferred that the temperature effect on the anisotropy decay in the BJ-35 micelle is mainly due to the thermal effect on the microviscosity in the micellar phase. In the case of TX-100, the results indicate that, along with the above thermal effect, an additional effect is observed due to the increased size and hydration of the micelle with temperature, with the result being that the fluorescence anisotropy decay in TX-100 is more sensitive to temperature than in BJ-35. In the TX-100 micelle, our studies show that with an increase in temperature, even though the micellar size increases substantially, the distance of the probe from the micellar core does not increase that significantly. Thus, with increasing temperature, the probe undergoes a relative migration toward the micellar core to avoid the increased hydration in the micellar Palisade layer. [source] RDC-assisted modeling of symmetric protein homo-oligomersPROTEIN SCIENCE, Issue 5 2008Xu Wang Abstract Protein oligomerization serves an important function in biological processes, yet solving structures of protein oligomers has always been a challenge. For solution NMR, the challenge arises both from the increased size of these systems and, in the case of homo-oligomers, from ambiguities in assignment of intra- as opposed to intersubunit NOEs. In this study, we present a residual dipolar coupling (RDC)-assisted method for constructing models of homo-oligomers with purely rotational symmetry. Utilizing the fact that one of the principal axes of the tensor describing the alignment needed for RDC measurement is always parallel to the oligomer symmetry axis, it is possible to greatly restrict possible models for the oligomer. Here, it is shown that, if the monomer structure is known, all allowed dimer models can be constructed using a grid search algorithm and evaluated based on RDC simulations and the quality of the interface between the subunits. Using the Bacillus subtilis protein YkuJ as an example, it is shown that the evaluation criteria based on just two sets of NH RDCs are very selective and can unambiguously produce a model in good agreement with an existing X-ray structure of YkuJ. [source] Geographic variation in offspring size of a widespread lizard (Takydromus septentrionalis): importance of maternal investmentBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010WEI-GUO DU Geographic variation in offspring size is widespread, but the proximate causes of this variation have not yet been explicitly determined. We compared egg size and egg contents among five populations of a lizard (Takydromus septentrionalis, Günther, 1864) along a latitudinal gradient, and incubated eggs at two temperatures to determine the influence of maternal investment and incubation temperature on offspring size. The mean values for female size and egg size were both greater in the two northern populations (Chuzhou and Anji) than in the three southern populations (Lishui, Dongtou, and Ningde). The larger eggs were entirely attributable to the body size of females in the Anji population, but their increased size also stemmed from further enlargement of egg size relative to female body size in Chuzhou, the northernmost population sampled in this study. Eggs of the Chuzhou population contained more yolk and less water than those of southern populations. Despite the lower lipid content in the yolk, eggs from the Chuzhou population had higher energy contents than those from the two southern populations, owing to the larger egg size and increased volume of yolk. Hatchling size was not affected by incubation temperature, but differed significantly among populations, with hatchlings being larger in the Chuzhou population than in the other populations. Our data provide an inference that oviparous reptiles from cold climates may produce larger offspring, not only by increasing egg size but also by investing more energy into their eggs. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 59,67. [source] Optical, structural, and magnetic properties of p-type GaN implanted with Fe+ (5 and 10 at%)PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2007Yoon Shon Abstract p-type GaN epilayers were prepared by metalorganic chemical vapor deposition and subsequently implanted with Fe+. The results of energy dispersive X-ray peak displayed the Fe-injected concentration of 5 and 10 at%, respectively. The results of photoluminescence measurement show that optical transitions related to Fe appear at 2.5 and 3.1 eV. It was confirmed that the photoluminescence peak at 2.5 eV is a donor-Fe acceptor transition and the photoluminescence peak at 3.1 eV is a conduction band-Fe acceptor transition. Apparent ferromagnetic hysteresis loops measured at 10 and 300 K with the Fe concentration of 10 at% were observed, and the temperature-dependent magnetization displayed a ferromagnetic behavior persisting up to 300 K. The systematic enhancement of ferromagnetic hysteresis loops for GaN implanted with high doses of Fe (5 , 10 at%) takes place with an increase in the annealing temperature from 700 to 850 °C. The trends of magnetic properties coincide with the results of the increased full width at half maximum of triple axis diffraction for GaN (0002) including the appearance of GaFeN, the enhanced Fe-related photoluminescence transitions, and the increased sizes of symmetric spin ferromagnetic domains GaFeN in atomic force microscopy and magnetic force microscopy systematically. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||