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Size Decreased (size + decreased)
Kinds of Size Decreased Selected AbstractsLife-history, genotypic, and environmental correlates of clutch size in the Glanville fritillary butterflyECOLOGICAL ENTOMOLOGY, Issue 2 2007MARJO SAASTAMOINEN Abstract 1.,Glanville fritillary butterfly (Melitaea cinxia) females lay up to 10 clutches of 50,300 eggs in their lifetime. Clutch size is an important life-history trait as larval group size affects survival throughout larval development. 2.,Two experiments were carried out in a large population cage in the field to investigate the life-history and environmental correlates of clutch size. 3.,Clutch size decreased with the cumulative number of eggs laid previously, increased with both female body weight and the number of days between consecutive clutches. 4.,Genotypic differences among females in the glycolytic enzyme phosphoglucose isomerase had a significant influence on clutch size, partly because females of particular genotypes were able to initiate oviposition earlier in the day and thereby take advantage of the most favourable environmental conditions for oviposition. 5.,Factors influencing clutch size were partly different in two summers, indicating the modulating effect of prevailing environmental conditions on reproductive performance. [source] Age-dependent clutch size in a koinobiont parasitoidECOLOGICAL ENTOMOLOGY, Issue 1 2005Jelmer A. Elzinga Abstract., 1. The Lack clutch size theory predicts how many eggs a female should lay to maximise her fitness gain per clutch. However, for parasitoids that lay multiple clutches it can overestimate optimal clutch size because it does not take into account the future reproductive success of the parasitoid. 2. From egg-limitation and time-limitation models, it is theoretically expected that (i) clutch size decreases with age if host encounter rate is constant, and (ii) clutch size should increase with host deprivation and hence with age in host-deprived individuals. 3. Clutch sizes produced by ageing females of the koinobiont gregarious parasitoid Microplitis tristis Nees (Hymenoptera: Braconidae) that were provided daily with hosts, and of females ageing with different periods of host deprivation were measured. 4. Contrary to expectations, during the first 2 weeks, clutch size did not change with the age of the female parasitoid, neither with nor without increasing host-deprivation time. 5. After the age of 2 weeks, clutch size decreased for parasitoids that parasitised hosts daily. The decrease was accompanied by a strong decrease in available eggs. However, a similar decrease occurred in host-deprived parasitoids that did not experience egg depletion, suggesting that egg limitation was not the only factor causing the decrease in clutch size. 6. For koinobiont parasitoids like M. tristis that have low natural host encounter rates and short oviposition times, the costs of reproduction due to egg limitation, time limitation, or other factors are relatively small, if the natural lifespan is relatively short. 7. Koinobiont parasitoid species that in natural situations experience little variation in host density and host quality might not have strongly evolved the ability to adjust clutch size. [source] Factors influencing the partitioning and toxicity of nanotubes in the aquatic environment,,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2008Alan J. Kennedy Abstract Carbon nanotubes (NTs) may be among the most useful engineered nanomaterials for structural applications but could be difficult to study in ecotoxicological evaluations using existing tools relative to nanomaterials with a lower aspect ratio. Whereas the hydrophobicity and van der Waals interactions of NTs may suggest aggregation and sedimentation in aquatic systems, consideration regarding how engineered surface modifications influence their environmental fate and toxicology is needed. Surface modifications (e.g., functional groups and coatings) are intended to create conditions to make NTs dispersible in aqueous suspension, as required for some applications. In the present study, column stability and settling experiments indicated that raw, multiwalled NTs (MWNTs) settled more rapidly than carbon black and activated carbon particles, suggesting sediment as the ultimate repository. The presence of functional groups, however, slowed the settling of MWNTs (increasing order of stability: hydroxyl > carboxyl > raw), especially in combination with natural organic matter (NOM). Stabilized MWNTs in high concentrations of NOM provided relevance for water transport and toxicity studies. Aqueous exposures to raw MWNTs decreased Ceriodaphnia dubia viability, but such effects were not observed during exposure to functionalized MWNTs (>80 mg/L). Sediment exposures of the amphipods Leptocheirus plumulosus and Hyalella azteca to different sizes of sediment-borne carbon particles at high concentration indicated mortality increased as particle size decreased, although raw MWNTs induced lower mortality (median lethal concentration [LC50], 50 to >264 g/kg) than carbon black (LC50, 18,40 g/kg) and activated carbon (LC50, 12,29 g/kg). Our findings stress that it may be inappropriate to classify all NTs into one category in terms of their environmental regulation. [source] Effects of an organophosphorous insecticide on survival, fecundity, and development of Hylyphantes graminicola (Sundevall) (Araneae: Linyphiidae)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2006Lingling Deng Abstract The effects of an organophosphorous insecticide, methamidophos, on fecundity and development of the spider Hylyphantes graminicola (Sundevall) (Araneae: Linyphiidae) were assessed under laboratory conditions. Susceptibility of adults of both sexes to the insecticide and its influence on fecundity of females and development of offspring were investigated. At 48 h after topical application in adults, the median lethal dose (LD50) and 10% lethal dose (LD10) were 0.35 and 0.12 ,g/spider, respectively, for males and 0.52 and 0.16 ,g/spider, respectively, for females. Methamidophos had detrimental effects on fecundity of females; number of eggs per clutch, total egg mass, and clutch size decreased significantly. The hatching rate of eggs from LD10-treated females was slightly higher than the rate in the controls, but the hatching rate of eggs from LD50-treated females was lower than the rate in the controls. However, no significant differences were observed in hatching time and development time across treatments. Development time of spiderlings from LD50-treated females was significantly longer than the time in the controls, and body sizes of the first spiderlings from insecticide-treated females were larger than those in the controls. However, matured offspring were smaller than those in the controls. It was concluded that methamidophos has long-term effects on H. graminicola, and that this may affect the development of spider populations in the field. [source] Geographic Variation in Male Sexual Signals in Strawberry Poison Frogs (Dendrobates pumilio)ETHOLOGY, Issue 9 2007Heike Pröhl In this paper, we compare the advertisement calls of 207 neotropical strawberry poison frogs (Dendrobates pumilio) collected in 21 localities along a transect from northern Costa Rica to western Panama. Populations varied most in call duration and call rate, while pulse rate and duty cycle were less variable. Multivariate analyses showed that call variation followed a cline with higher call rates, shorter calls, lower duty cycles and higher pulse rates in the southeast. Body size decreased towards the southeast and explained most variation in dominant frequency, as well as some residual variation in call rate. We conclude that a combination of geography and morphology is largely responsible for call variation within this species. Two inferred bio-acoustic groups were roughly in accordance with two genetic groups, geographically separated in central Costa Rica. However, genetic distances among populations did not co-vary with call dissimilarity after correction for geographic distances. Thus, differences in calls between genetic groups are probably mainly a result of clinal variation. These findings agree with the general observation that bio-acoustic variation is often not (highly) associated with genetic divergence. Moreover, colour polymorphism observed among Panamanian populations was not reflected in a higher variability in call parameters relative to the monomorphic Costa Rican populations. [source] EVOLUTIONARY REDUCTION IN TESTES SIZE AND COMPETITIVE FERTILIZATION SUCCESS IN RESPONSE TO THE EXPERIMENTAL REMOVAL OF SEXUAL SELECTION IN DUNG BEETLESEVOLUTION, Issue 10 2008Leigh W. Simmons Sexual selection is thought to favor the evolution of secondary sexual traits in males that contribute to mating success. In species where females mate with more than one male, sexual selection also continues after copulation in the form of sperm competition and cryptic female choice. Theory suggests that sperm competition should favor traits such as testes size and sperm production that increase a male's competitive fertilization success. Studies of experimental evolution offer a powerful approach for assessing evolutionary responses to variation in sexual selection pressures. Here we removed sexual selection by enforcing monogamy on replicate lines of a naturally polygamous horned beetle, Onthophagus taurus, and monitoring male investment in their testes for 21 generations. Testes size decreased in monogamous lines relative to lines in which sexual selection was allowed to continue. Differences in testes size were dependent on selection history and not breeding regime. Males from polygamous lines also had a competitive fertilization advantage when in sperm competition with males from monogamous lines. Females from polygamous lines produced sons in better condition, and those from monogamous lines increased their sons condition by mating polygamously. Rather than being costly for females, multiple mating appears to provide females with direct and/or indirect benefits. Neither body size nor horn size diverged between our monogamous and polygamous lines. Our data show that sperm competition does drive the evolution of testes size in onthophagine beetles, and provide general support for sperm competition theory. [source] EFFECTS OF POLLEN LOAD SIZE ON SEED PATERNITY IN WILD RADISH: THE ROLES OF POLLEN COMPETITION AND MATE CHOICEEVOLUTION, Issue 8 2007Diane L. Marshall For sexual selection to be important in plants, it must occur at pollen load sizes typical of field populations. However, studies of the impact of pollen load size on pollen competition have given mixed results, perhaps because so few of these studies directly examined the outcome of mating when pollen load size was varied. We asked whether seed paternity after mixed pollination of wild radish was affected by pollen load sizes ranging from 22 to 220 pollen grains per stigma. We examined the seed siring abilities of 12 pollen donors across 11 maternal plants. Seed paternity was statistically indistinguishable across the pollen load sizes even though, overall, the pollen donors sired different numbers of seeds. This lack of effect of pollen load size on seed paternity may have occurred because fruit abortion and early abortion or failure of fertilization of seeds increased as load size decreased. Thus, failures of fruits and seeds sired by poorer pollen donors may keep seed paternity constant across pollen load sizes. [source] Double-nesting behaviour and sexual differences in breeding success in wild Red-legged Partridges Alectoris rufaIBIS, Issue 4 2009FABIÁN CASAS Double-nesting behaviour, a rare breeding system in which females lay in two nests, one incubated by herself and the other one by her mate, could be considered an intermediate stage in the evolutionary trend from biparental to uniparental care of single clutches. We examined the occurrence and success of double-nesting behaviour in Red-legged Partridges Alectoris rufa in Central Spain. Clutch size and hatching success were recorded, as well as the variation in these between years and between incubating sexes. Participation in incubation was higher for females (94.76%) than males (41.0%), and the proportion of incubating males varied markedly between years, with no incubating males in one dry year and approximately 50% of males incubating in other years. There was significant variation among years and between sexes in laying date, clutch size and hatching success. Clutch size decreased with later laying date in males and females. The probability of clutch loss to predation differed between sexes, being much higher for nests incubated by females. Our results suggest that both rainfall and predation influence the occurrence and success of double-nesting. [source] Changes in clutch size, brood size and numbers of nesting Squacco Herons Ardeola ralloides over a 32-year period in the Camargue, southern FranceIBIS, Issue 1 2001HEINZ HAFNER Changes in numbers of nesting pairs, clutch size, and brood size of Squacco Herons Ardeola ralloides in the Camargue, southern France were analysed over a 32-year period. The annual numbers of breeding pairs [average 84 pairs pL 30 sd, n = 32 years) exhibited a possible increasing trend, but with considerable variability. This variability is associated with local spring rainfall, which may influence the available surface area of their preferred freshwater habitats. In contrast to population size, clutch size decreased substantially in recent years. Our data do not provide a causal explanation for this change in clutch size, although the reduction temporally corresponds with increasing rice cultivation and with a dramatic increase in the number of Cattle Egrets Bubulcus ibis in the Camargue. [source] Endoluminal repair of distal aortic arch aneurysms causing aorto-vocal syndromeINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 10 2008J. P. Morales Summary Purpose:, We have evaluated the efficacy of endovascular repair of distal aortic arch aneurysms (DAAA) causing recurrent laryngeal nerve palsy. Material and methods:, Eight patients (five male and three female) with median age of 72 years (range: 59,80) presented with left recurrent laryngeal nerve palsy associated with DAAA. All patients were considered unfit for open surgery. The median aneurysm size was 5.9 cm (range: 5,7.3). Thirteen stents were deployed: eight Gore, four Endofit and one Talent. Epidural anaesthesia was used in all patients. The left subclavian artery was covered in all and the left common carotid in three who had a preliminary right to left carotid,carotid bypass. Routine follow-up (FU) was with computed tomography (CT) at 3,6 months and yearly thereafter. Results:, Exclusion of the aneurysm sac was achieved in all patients. Thirty-day mortality was 0%, with no paraplegia or stroke. Early complications included: rupture of the external iliac artery (one) and common femoral artery thrombectomy (one). One patient died of unknown cause at 17 months. The mean FU in the remaining seven patients was 21 months (range: 6,51). Aneurysm size decreased in five, was unchanged in one and increased in one. Three patients had improvement in voice quality postoperatively. One patient had a recurrent type 1 endoleak which was restented twice. No late deaths have occurred. Conclusion:, Though technically the procedures involved were more complicated, endovascular repair of DAAA causing aorto-vocal syndrome is safe and offers a realistic alternative to open surgery. Hoarseness of the voice can improve postoperatively and is associated with reduction in aortic sac diameter. [source] Composites of rigid polyurethane foam and cellulose fiber residueJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010M. C. Silva Abstract Rigid polyurethane composite foams were prepared with cellulose fibers as a filler. The cellulose fibers were an industrial residue of blanched cellulose pulp production. The influence of the cellulose fiber concentration on the structural, thermal, mechanical, and morphological properties of the foams was investigated. We also studied the influence of the cellulose fibers on the foam's resistance to fungal attack by placing a suspension of known fungus in contact with the surface of the foam and following the morphological evolution as a function of time (for 60 days). The increase in the cellulose filler concentration in the foams, up to 16% w/w with respect to the polyol, changed their properties as follows: (1) the cell size decreased, (2) the thermooxidative stability and mechanical properties remained approximately constant, (3) the thermal conductivity decreased slightly, and (4) fungal growth was observed. Therefore, a cellulosic fibrous industrial residue was rationally valorized as a filler in classical rigid polyurethane foams; this yielded materials with mechanical resistance and a susceptibility to fungi in a wet environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Patterns in diversity of anurans along an elevational gradient in the Western Ghats, South IndiaJOURNAL OF BIOGEOGRAPHY, Issue 5 2007Rohit Naniwadekar Abstract Aim, To examine patterns in anuran species richness along an elevation gradient and identify factors that govern anuran species richness on a tropical elevational gradient. Location, Sampling for anurans was carried out in Kalakad Mundanthurai Tiger Reserve (KMTR) in the southern Western Ghats, India. Methods, Night-time sampling for anuran species richness was carried out from 20 November 2004 to 20 April 2005, during the north-east monsoon and dry seasons, using transects (50 × 2 m) and visual encounter surveys along the streams. The entire gradient was classified into thirteen 100-m elevation zones. Sampling at the alpha (single drainage basin) level was carried out in the Chinnapul River drainage basin (40,1260 m a.s.l.) and at the gamma (landscape) level in four drainage basins. Additionally, published records were used to arrive at an empirical species richness (S) for the entire landscape. Mid-Domain Null software was used to test for the possible influence of geometric constraints on anuran species at both the alpha and gamma levels. The influence of area under each elevation zone on empirical S was tested. The pattern in anuran species richness along the elevational gradient was investigated using: (1) species boundaries in each elevation zone and their habitat correlates, (2) abiotic factors as predictor variables, (3) mean snout vent lengths of anurans, and (4) correlation between the matrices of distance in the elevation zones based on microhabitat parameters and species composition. Cluster analysis on species presence,absence in the elevation zones was used to categorize the entire gradient into high, middle and low elevations. In these three elevation categories, pattern in composition of species was examined for endemism in Western Ghats,Sri Lanka biodiversity hotspot, uniqueness to an elevation zone, adaptations of adults and modes of breeding. Results, Species richness at the alpha level increased linearly with elevation, while at the gamma level there were three peaks. Maximum species richness was observed at the highest elevation (1200 m) at both the alpha and the gamma levels. The observed patterns differed significantly from mid-domain null predictions. The multi-modal pattern in species richness was a consequence of overlapping species range boundaries. Soil temperature was the best single measure in explaining the majority of variation in species richness at the alpha level (r2 = 0.846, P < 0.01). However, soil moisture was the best predictor when both the alpha and the gamma sites were pooled (r2 = 0.774, P < 0.01). Anuran body size decreased with an increase in elevation. The highest proportions of endemic and unique species were found at high elevations (> 700 m). The proportion of arboreal anurans increased from low to high elevation. Anurans exhibiting direct development were predominantly found at high elevations. Main conclusions, Geometric constraints did not influence anuran species richness along the elevational gradient. Overlapping range boundaries influenced species richness at the gamma level. Abiotic factors such as soil temperature and moisture influenced anuran species richness in the mountain range. The ,Massenerhebung effect' could be responsible for range restriction and endemism of anurans, differences in guilds and mode of reproduction. These findings highlight the importance of cloud forests for endemic anurans. [source] Hunting, disturbance and roost persistence of bats in caves at Ankarana, northern MadagascarAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009Scott G. Cardiff Abstract Surveys and monitoring of 37 caves in and around the Ankarana Special Reserve, northern Madagascar, yielded evidence of hunting of bats and potential disturbance of bats by miners and tourists, and colony counts for several bat species of potential conservation concern. Colony size decreased by 95% and 14% for a colony of Hipposideros commersoni and a colony of Eidolon dupreanum, respectively, when recent evidence of hunting occurred at those colonies and those declines are probably attributable to hunting. Evidence of hunting occurred commonly at the roosts of those species and most commonly at the roosts of Rousettus madagascariensis. Hunting of pteropodids was associated with high vulnerability of roosts to hunters, little forest buffer between the cave and open savannah and the absence of tombs in the cave. Roost sites of the hunted species persisted for at least several years and this regularity may facilitate hunting. This work supports the ranking of E. dupreanum, R. madagascariensis and H. commersoni as species of conservation concern. Managers should consider the impact of tourist visits on bats and of increasing access to caves for tourism. Conservation efforts for the hunted species should also seek to protect vulnerable and unprotected cave roosts. Résumé Des études et un suivi continu de 37 grottes dans la Réserve Spéciale d'Ankarana et dans les environs, dans le nord de Madagascar, ont permis de récolter des preuves de la chasse aux chauves-souris et de l'éventuel dérangement des chauves-souris par des mineurs et des touristes; et des comptes de colonies pour plusieurs espèces dont le statut de conservation pourrait être inquiétant. La taille des colonies avait baissé de 95% et de 14% respectivement pour Hipposideros commersoni et pour Eidolon dupreanum, lorsque des preuves récentes de chasse sont apparues dans ces colonies; ces déclins sont probablement dus à la chasse. Des preuves de chasse étaient réguliérement présentes aux dortoirs de ces espèces, et plus communes encore aux dortoirs de Rousettus madagascariensis. La chasse des ptéropodidés était associée à une grande vulnérabilité des dortoirs face aux chasseurs, à une petite zone forestière tampon entre la grotte et la savane ouverte, et à l'absence de tombes dans la grotte. Les sites de repos des espèces chassées existaient depuis plusieurs années au moins, et cette persistance pourrait faciliter la chasse. Ce travail soutient le classement de E. dupreanum, R. madagascariensis et H. commersoni parmi les espèces dont le statut de conservation est inquiétant. Les gestionnaires devraient considérer l'impact des visites de touristes sur les chauves-souris et de l'augmentation de l'accès aux grottes pour le tourisme. Les efforts de conservation des espèces chassées devraient aussi viser à protéger les dortoirs dans des grottes vulnérables et non protégées. [source] Fluctuating asymmetry of sexual and nonsexual traits in stalk-eyed flies: a poor indicator of developmental stress and genetic qualityJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2000Bjorksten It has been proposed that females use fluctuating asymmetry (FA) in sexual ornaments to assess male quality. FA of sexual traits is predicted to show greater sensitivity to stress than FA of nonsexual traits, and to be heritable. We used a half-sib mating design and manipulation of larval food environment to test these predictions on stalk-eyed flies, Cyrtodiopsis dalmanni, in which females prefer males with larger eyespans. We measured size and FA of eyestalks and of two nonsexually selected characters, wing length and width. We found no evidence of an increase in FA under larval food stress in any of the individual traits, although trait size decreased under stress. We combined FA across traits into a single composite index, and found that males reared in the most benign larval environment had significantly higher composite FA than males reared on other media. There was no such effect in females. Heritability of FA was not significantly different from zero in any of the traits, in any of the environments, although trait sizes showed high heritability. We conclude that FA in sexual and nonsexual traits is a poor indicator of developmental stress and genetic quality. [source] Formation of monodisperse microbubbles in a microfluidic deviceAICHE JOURNAL, Issue 6 2006J. H. Xu Abstract The crossflowing rupture technique was first used in a microfluidic device to prepare microbubbles, and successfully prepared monodisperse microbubbles with polydispersity index (,) values of <2%. The parameters affecting the microbubble-formation process, such as two-phase flow rates, continuous-phase viscosity, surface tension, and surfactants were investigated. The microbubble-formation mechanisms of the crossflowing rupture technique with those of the techniques of both flow-focusing rupture and geometry-dominated breakup were also compared. It was also found that the bubble size decreased with increasing continuous-phase rate and its viscosity, while independent of surface tension. The different species of surfactants also influenced the microbubble-formation process. Moreover, the bubble-formation mechanism by using the crossflow rupture technique was different from the techniques of both hydrodynamic flow focusing and geometry-dominated breakup. The microbubble-formation process using the crossflowing rupture technique is controllable. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source] Electric and Dielectric Properties of Nb-Doped CaCu3Ti4O12 CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2007Seong-Hyeon Hong Pure and Nb-substituted CaCu3Ti4,xNbxO12+x/2 (CCTO, x=0, 0.02, 0.1, 0.2, 0.4) ceramics were prepared by a conventional solid-state sintering, and their electric and dielectric properties were investigated using an impedance analyzer. A single-phase CCTO was obtained up to x=0.2 Nb substitution and the lattice parameter increased with Nb substitution concentration. While the grain size decreased with Nb substitution, the resistivity of the grain boundary decreased. The dielectric constant increased with Nb substitution, and the highest value of ,420 000 was observed in the x=0.2 Nb-substituted specimen at 10 kHz. The obtained electric and dielectric properties in Nb-substituted CCTO were discussed in terms of the internal barrier layer capacitor model, particularly focusing on a ratio of thickness of the grain boundary region to grain size. [source] Silicon Nitride,Silicon Carbide Nancocomposites Fabricated by Electric-Field-Assisted SinteringJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2003Julin Wan Starting with Si-C-N(-O) amorphous powders, and using the electric field assisted sintering (EFAS) technique, silicon nitride/silicon carbide nanocomposites were fabricated with yttria as an additive. It was found that the material could be sintered in a relatively short time (10 min at 1600°C) to satisfactory densities (2.96,3.09 g/cm3) using 1,8 wt% yttria. With decreasing yttria content, the ratio of SiC to Si3N4 increased, whereas the grain size decreased from ,150 nm to as small as 38 nm. This offers an attractive way to make nano-nanocomposites of silicon nitride and silicon carbide. [source] Clinical, Echocardiographic, and Neurohormonal Effects of a Sodium-Restricted Diet in Dogs with Heart FailureJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 5 2000John E. Rush The use of low-sodium diets in dogs with heart failure is common practice, but randomized, double-blind studies have not been conducted to examine the benefits or problems with this approach. The purpose of this study was to determine the effects of a low-sodium diet on clinical, echocardiographic, and neurohormonal parameters in dogs with heart failure. Dogs with stable chronic heart failure were fed exclusively a low-sodium (LS) and a moderate-sodium (MS) diet for 4 weeks each in a randomized, double-blind, crossover design. At days 0, 28, and 56, echocardiography and thoracic radiography were performed, and blood was analyzed for electrolytes and neurohormones. Fourteen dogs completed the study (9 with chronic valvular disease and 5 with dilated cardiomyopathy). Electrolyte abnormalities were common during the study, and serum sodium and chloride concentrations decreased significantly on the LS diet. Neurohormones did not change significantly between diet groups. Maximum left atrial (P= .05) and standard left atrial (P= .09) size decreased on the LS diet. For dogs with chronic valvular disease, vertebral heart score (P= .05), left ventricular internal dimension in diastole (P= .006) and systole (P= .02), standard left atrial dimension (P = .03), maximum left atrial dimension (P= .02), end-diastolic volume index (P= .02), and end-systolic volume index (P= .04) decreased significantly on the LS diet compared to the MS diet. Although analysis of these data suggests some benefits of a low-sodium diet, future studies with improved study design are needed to further evaluate the advantages and disadvantages of sodium restriction in dogs with heart failure. [source] Preparation of Polystyrene/Clay Nanocomposites by Free-Radical Polymerization in DispersionMACROMOLECULAR MATERIALS & ENGINEERING, Issue 11 2009Nagi Greesh Abstract Fully exfoliated PS/clay nanocomposites were prepared via FRP in dispersion. Na-MMT clay was pre-modified using MPTMS before being used in a dispersion polymerization process. The objective of this study was to determine the impact of the clay concentrations on the monomer conversion, the polymer molecular weight, and the morphology and thermal stability of the nanocomposites prepared via dispersion polymerization. DLS and SEM revealed that the particle size decreased and became more uniformly distributed with increasing clay loading. XRD and TEM revealed that nanocomposites at low clay loading yielded exfoliated structures, while intercalated structures were obtained at higher clay loading. [source] Using Chitosan as a Nucleation Agent in Thermoplastic Foams for Heavy Metal AdsorptionMACROMOLECULAR SYMPOSIA, Issue 1 2009Milton O. Vázquez Abstract Thermoplastics/chitosan-powder composite foams were prepared by extrusion using azodicarbonamide (ACA) as chemical blowing agent. The effect of chitosan content on morphology (cell size, nucleation density and foam density) of the foams was studied. Chitosan particles are located on the bubbles periphery. Morphological quantification showed that foam cell size decreased and cell population increased with addition of chitosan into polymeric matrix from 1 to 10%. Further, optimum chitosan content was obtained for each polymer. Polymers foamed with chitosan were tested as a chelating resin to adsorb chromium (Cr VI) from different concentration solutions. [source] Configurations of germinal vesicle (GV) chromatin in the goat differ from those of other speciesMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2005Hong-Shu Sui Abstract Configuration of germinal vesicle (GV) chromatin has been studied and found correlated with the developmental competence of oocytes in several mammalian species. A common feature in the configuration of GV chromatin in the species studied so far is that the diffuse chromatin (the so called "NSN" pattern) condenses into a perinucleolar ring (the so called "SN" configuration) with follicular growth. However, no study has been published on the configuration of GV chromatin in the goat. Nor is it known whether the perinucleolar ring of condensed chromatin (CC) in an oocyte represents a step toward final maturation or atresia. Changes in configurations of GV chromatin and RNA synthesis during goat oocyte growth, atresia and maturation in vivo and in vitro were investigated in this study. Based on both the size of nucleoli and the degree of chromatin condensation, the GV chromatin of goat oocytes was classified into GV1 characterized by large nucleoli and diffuse chromatin, GV2 with medium-sized nucleoli and condensed net-like (GV2n) or clumped (GV2c) chromatin, GV3 with small nucleoli and net-like (GV3n) or clumped (GV3c) chromatin, and GV4 with no nucleolus but clumped chromatin. The results showed that (i) the configurations of GV chromatin in the goat differ from those of other species in that the chromatin did not condense into a perinucleolar ring; (ii) most of the goat oocytes are synchronized at the GV3n configuration before GVBD; (iii) the GVn pattern might represent a healthy state, but the GVc an atretic state; (iv) in both goats and mice, the GC-specific (Chromomycin A3, CMA3) and the AT-specific (Hoechst 33342) fluorochromes followed the same pattern of distribution in GV chromatin; (v) the nucleolar size decreased significantly with oocyte growth and maturation in vivo and in vitro; and (vi) goat oocytes began GVBD at 8 hr and had completed it by 20 hr after onset of estrus. The peculiar configuration of GV chromatin of goat oocytes can be a useful model for studies of morphological and functional changes of different nuclear compartments during the cell cycle and cell differentiation, and the functional differentiation between GV3n and GV3c might be used for reference to the question whether the "SN" configuration in other species inclines toward ovulation or atresia. Mol. Reprod. Dev. 71: 227,236, 2005. © 2005 Wiley-Liss, Inc. [source] Effect of eggshell powder as nucleating agent on the structure, morphology and functional properties of normal corn starch foams,PACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2007Yixiang Xu Abstract Corn starch and eggshell powder (with particle sizes of 4,5µm and 8,10µm) composite foams were prepared by extrusion. Effects of eggshell on the structure, morphology, physical properties (unit density and expansion ratio), mechanical properties (spring index and compressibility) and thermal behaviour (thermal transition and stability) of the foams were investigated. Foam cell size decreased and cell population increased with addition of eggshell into starch matrix. The foam unit density, expansion ratio and compressibility decreased significantly (p < 0.05), while the spring index increased significantly (p < 0.05) as the eggshell content increased from 0 to 6wt%. Further increasing eggshell content to 10wt% increased the unit density and compressibility and decreased the expansion ratio and spring index. The thermal transition and stability increased with the addition of eggshell. The optimum eggshell content was 6wt% and the smaller-sized eggshell powder had a favourable effect on the functional properties of the foams. Copyright © 2006 John Wiley & Sons, Ltd. [source] Life cycle environmental performance and improvement of a yogurt product delivery systemPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2004Gregory A. Keoleian Abstract A life cycle assessment was conducted to evaluate the environmental performance of the yogurt product delivery system used by Stonyfield Farm. A life cycle model was developed which included material production, manufacturing and disposition for primary and secondary packaging, as well as the related transportation links between these stages and filling, retail and the point of consumption. Product delivery systems (PDS) that utilized 4, 6, 8 and 32,oz polypropylene (PP) cups and 2,oz linear low-density polyethylene (LLDPE) tubes were analysed. Ten strategies for improving the environmental performance of these systems were proposed and their impacts on the total life cycle burden were analysed. The life cycle energy consumption for the 2, 4, 6, 8 and 32,oz containers was 4050, 4670, 5230, 4390 and 3620,MJ/1000,lb yogurt delivered to market, respectively. Material production of the primary packaging accounted for 58% of the life cycle energy, while Distribution 3 (yogurt delivery to distributors/retailers) alone accounted for one-third of the life cycle total energy. The life cycle solid waste profile showed that as the container size decreased, the solid waste burden increased, from 27.3,kg (32,oz) to 42.8,kg (6,oz) per 1000,lb yogurt delivered to market. This relationship was even more pronounced for the 4,oz (47.5,kg) and 2,oz (56.2,kg) product delivery systems. The greatest potential improvements in the environmental performance of the PDS are achievable through redesigning the primary packaging and using alternative manufacturing techniques for the yogurt cups. Shifting from injection moulding to thermoforming of 32,oz container reduces the life cycle energy and solid waste by 18.6% and 19.5%, respectively, primarily due to light-weighting. Elimination of lids for 6,oz and 8,oz containers provided similar benefits. Consumers purchasing yogurt in 32,oz instead of 6,oz containers can save 14.5% of the life cycle energy and decrease solid waste by 27.2%. Copyright © 2004 John Wiley & Sons, Ltd. [source] Morphological changes of sperm nuclei during spermatogenesis in the brown alga Cystoseira hakodatensis (Fucales, Phaeophyceae)PHYCOLOGICAL RESEARCH, Issue 2 2003Shinya Yoshikawa SUMMARY Morphological changes and chromatin condensation of sperm nuclei were observed during spermatogenesis in the fucalean brown alga Cystoseira hakodatensis (Yendo) Fensholt. Ultrastructural studies have shown that the mature spermatozoid has an elongated and concave nucleus with condensed chromatin. The morphological changes and the chromatin condensation process during spermatogenesis was observed. Nuclear size decreased in two stages during spermatogenesis. During the first stage, spherical nuclei decreased in size as they were undergoing meiotic divisions and the subsequent mitoses within the antheridium. During the second stage, the morphological transformation from a spherical into an elongated nucleus occurred. Afterwards, chromatin condensed at the periphery in each nucleus, and chromatin-free regions were observed in the center of the nucleus. These chromatin-free regions in the center of nucleus were compressed by the peripheral chromatin-condensed region. As the result, the elongated and concave nucleus of the mature sperm consisted of uniformly well-condensed chromatin. [source] Atmospheric Cold Plasmas for Synthesizing Nanocrystalline Anatase TiO2 using Dielectric Barrier DischargesPLASMA PROCESSES AND POLYMERS, Issue 5 2007Long-Hui Nie Abstract Nanocrystalline anatase TiO2 has been successfully synthesized using TiCl4 and O2 as precursors by atmospheric cold plasmas generated by dielectric barrier discharges (DBD) without extra heating or thermal treatment. For the TiO2 powders synthesized by DBD plasma at an energy density of 5.9 kJ,·,L,1, XRD and TEM analyses revealed that the nanocrystallite size is about 10,15 nm. Only a single crystalline structure of anatase was observed performing XRD, HRTEM and SAED measurements. It was found that the particle size decreased with increasing the discharge power, and that the chlorine contamination dramatically decreased when using high discharge power levels. [source] Morphologies and applied properties of PSI/PA composite particles synthesized at low temperaturePOLYMER COMPOSITES, Issue 11 2008Yumin Wu Latex with a poly(dimethyl-siloxane) core and a poly(methylmethacrylate- butylacrylate- 2-hydroxypropyl acrylate) shell have been prepared at low temperature with potassium-persulphate (KPS), sodium formaldehyde sulfoxylate (SFS) and 2,2,-azobis [2-(2-imidazolin- 2-yl)propane] dihydrochloride (VA-044) as composite initiators by staged emulsion polymerization. Reactive surfactants were used to significantly improve the applied properties such as water adsorption ratio and thermo-properties. Transmission electron microscopy (TEM) results indicated that increasing the amount of 2-hydroxypropyl acrylate (HPA) and butylacrylate (BA) was favorable to form the core/shell particles. Particle size distribution results showed with increasing the dosages of surfactants, initiators, and seed-latex, particle size decreased. Differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) results indicated the high temperature-reserved of copolymer was improved in the presence of polysiloxane. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] The effect of stoichiometry on the fracture toughness of a liquid crystalline epoxyPOLYMER ENGINEERING & SCIENCE, Issue 2 2002Elizabeth J. Robinson The fracture toughness of a liquid crystalline epoxy was compared with that of a standard bisphenol-A based epoxy to understand how both the liquid crystalline structure and the crosslink density affect fracture toughness. For the liquid crystalline epoxy, the liquid crystalline domain size decreased with increasing temperature of cure and away from the stoichiometric formulation. Quantitative fractography showed that there is a competition between the liquid crystalline domain structure and the stoichiometry in determining the fracture toughness. At some cure conditions the effect of the domains is dominant. When the cure conditions are adjusted to reduce the domain size, the domains become too small to affect the fracture toughness, and thus the effect of the stoichiometry is dominant. The result is that the formation of liquid crystalline structure only increases the fracture toughness relative to that of a traditional epoxy at and near the stoichiometric formulation. [source] Age- and site-specific decline in insulin-like growth factor-I receptor expression is correlated with differential growth plate activity in the mouse hindlimbTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 4 2007Maria A. Serrat Abstract The proximal and distal growth plates of the principal long bones do not contribute equally to longitudinal growth. Most forelimb elongation occurs at the shoulder and wrist, while most hindlimb growth occurs at the knee. This study examined whether insulin-like growth factor-I (IGF-I), a potent growth regulator, could underlie this variation via differential receptor expression. The spatiotemporal distribution of the IGF-I receptor (IGF-IR) was mapped in hindlimb growth plates (overall and within regional zones) from immature mice using immunohistochemistry. Growth activity was assessed by size/morphology of the growth plate and proliferating cell nuclear antigen (PCNA) expression. Both IGF-IR and PCNA staining declined considerably with age in the proximal femur and distal tibia (hip and ankle), but expression remained high in the more active distal femur and proximal tibia (knee) throughout growth. Growth plate size decreased with age in all sites, but the absolute and relative decline in IGF-IR in the hips and ankles of older mice indicated a site-specific loss of IGF-I sensitivity in these less active regions. These results suggest that regulation of the IGF-IR may at least partially mediate differential long bone growth, thereby providing a local mechanism for altering skeletal proportions absent modification of systemic hormone levels. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Acoustic Neuroma in a Private Neurotology Practice: Trends in Demographics and Practice PatternsTHE LARYNGOSCOPE, Issue 11 2007Douglas A. Chen MD Abstract Objectives/Hypothesis: To determine whether changes in demographics and management of patients with acoustic neuromas occurred between the years 1990 and 2005. Study Design: Retrospective chart review. Methods: Charts of all 614 patients with a diagnosis of acoustic neuroma, excluding neurofibromatosis-2, from 1990 through 2005 were reviewed. Age at diagnosis, tumor size, hearing, and initial therapy (observation, stereotactic radiation, or surgical excision) were obtained. Patients were grouped by time period (1990,1994, 1995,2000, 2001,2005). Results: Mean age at diagnosis increased slightly from the middle period (53.4 yr) to the most recent (56.9 yr) (P , .025). The proportion of patients 65 years or older increased from 21% to 29% to 32%, respectively, but the change was not significant. Average tumor size decreased from 1.7 cm initially to 1.4 cm most recently (P , .039). There were no significant changes in hearing. Although surgical excision remains our most common treatment (58.5% in 2001,2005), it is becoming less frequent (>80% in earlier periods) (P , .001). Observation with serial imaging was recommended in 37.3% in 2001 to 2005 as compared with 18.3% and 11.6% in the previous two time periods (P , .001). These changes in initial treatment choices occurred for all age groups and primarily for small tumors. Use of radiation has increased only slightly, to 4.2% in the recent period. Conclusion: Patients with acoustic neuroma are presenting with increased age and smaller tumors compared with 16 years ago. However, these changes cannot totally account for the large change in treatment trends. Technology and demographics are influential in these changes, but other difficult to measure forces, such aspatient influence and patient use of the Internet, are also factors. [source] Anti-apoptotic genes Aven and E1B-19K enhance performance of BHK cells engineered to express recombinant factor VIII in batch and low perfusion cell cultureBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2007Toey Nivitchanyong Abstract The engineering of production cell lines to express anti-apoptotic genes has been pursued in recent years due to potential process benefits, including enhanced cell survival, increased protein expression, and improved product quality. In this study, a baby hamster kidney cell line secreting recombinant factor VIII (BHK-FVIII) was engineered to express the anti-apoptotic genes Aven and E1B-19K. In high cell density shake flask culture evaluation, 11 clonal cell lines expressing either E1B-19K or a combination of Aven and E1B-19K showed improved survival compared to both parental and blank vector cell line controls. These cell lines exhibited lower caspase-3 activation and reduced Annexin-V binding compared to the controls. Parental and blank vector cell lines were less than 50% viable after 48 h of exposure to thapsigargin while cell lines expressing E1B-19K with or without Aven maintained viabilities approaching 90%. Subsequently, the best Aven-E1B-19K candidate cell line was compared to the parental cell line in 12-L perfusion bioreactor studies. Choosing the appropriate perfusion rates in bioreactors is a bioprocess optimization issue, so the bioreactors were operated at sequentially lower specific perfusion rates, while maintaining a cell density of 2,×,107 viable cells/mL. The viability of the parental cell line declined from nearly 100% at a perfusion rate of 0.5 nL/cell/day to below 80% viability, with caspase-3 activity exceeding 15%, at its lower perfusion limit of 0.15 nL/cell/day. In contrast, the Aven-E1B-19K cell line maintained an average viability of 94% and a maximum caspase-3 activity of 2.5% even when subjected to a lower perfusion minimum of 0.1 nL/cell/day. Factor VIII productivity, specific growth rate, and cell size decreased for both cell lines at lower perfusion rates, but the drop in all cases was larger for the parental cell line. Specific consumption of glucose and glutamine and production of lactate were consistently lower for the Aven-E1B-19K culture. Furthermore, the yield of ammonia from glutamine increased for the Aven-E1B-19K cell line relative to the parent to suggest altered metabolic pathways following anti-apoptosis engineering. These results demonstrate that expression of anti-apoptotic genes Aven and E1B-19K can increase the stability and robustness of an industrially relevant BHK-FVIII mammalian cell line over a wide range of perfusion rates. Biotechnol. Bioeng. 2007; 98: 825,841. © 2007 Wiley Periodicals, Inc. [source] | |||||||||||||||||||