bluuebunny/crossref_metadata_2025_split huggingface dataset:
A mathematical model of the food‐consumer system I. A case without food replenishment
Authors: Ishihara Michio , Hozumi Kazuo , Shinozaki Kichiro 
Published: November 2006

SummaryA simple mathematical model was proposed to describe the dynamics of a food‐consumer system. The model was based on the Logistic Theory and consisted of Eqs. (4), (5) and (6). The model was divided into the following three cases for further analyss; i) without food supply except at the initial time, ii) with continuous food supply at a constant rate, and iii) with food supply at varying rates. Only the first model was dealth with in this paper.The assumptions of the model 1 are that a definite amount of food is given only once at the initial time and only the feeding by animals is responsible for the decrease of food, and that the rate of decrease is proportional to the amount of animals. It is also assumed that the growth of animal population is represented by the logistic curve, and that the upper limit of the population is proportional to the amount of food at that time. For simplicity the parameters of basic differential equations are assumed to be constant throughout the time course.Analytical solutions of this non‐linear model were given by Eqs. (8), (9), (10) and (11). The properties of time course of the food amount and consumer population were discussed from the mathematical and biological points of view. The method of the estimation of the three constants λ,b, and c from the experimental data was also suggested.Since we had no available data for animal populations, we applied the model, regarding reserve substance as x and new plant body as y, to the data of the initial growth of Azuki bean plant in the dark.This model is very simple, but it may be useful for analyzing the behavior of food‐consumer system. And it may give some clue to the analysis of the more complex systems.
Investigation into the edge effect by use of capture‐recapture data in a vole population
Authors: Tanaka Ryo 
Published: November 2006

SummaryA substantial explication of the edge effect has been attempted by use of capture‐recapture data for a vole population (Microtus montebelli), gathered intwo plots of 100×100 m or less during 12 days, cheked twice daily, in August 1970; the sample was quite sufficient for the aim.The edge effect as guessed by increased catch per trap is usually suspected to ensue from range‐settlers in the outside boundary strip of a plot and immigrants. But by a theoretical analysis I could attain a tentative conclusion that no increased catch per trap will occur unless any invasion takes place. Then it follows that, apart from the effect of invasion, the role of the adjoining outside settlers in the edge effect is essentially required to be studied in the light of knowledge on the truth of size and shift in home range.The variation in range behavior for 183 adult voles, captured 6 times or more, could be grouped into eight types, of which the range‐conservative type possessed 52% of the sample and the group of the type was justly utilized for giving averages of range size. Besides, it was seen from the observed frequency of types that a considerable number of immigrants onto the census plot were induced perhaps being allured by trap baits, but the majority of them proved to be assigned to the voles that have their ranges inside the assessment line ofDice; the rest referable to effective immigrants was only a few (7%). I could perceive no reason such as disproves the idea ofDice's additional boundary strip.Viewed from maps of ingress shift of ranges, the effect of ingress must have been greater in the outer trap rows than in the inner within the plot, so that it might well be called edge effect in general; such effect, however, is seen gradually diminishing toward the center, and hence it is almost unlikely that one should find any clear‐cut intra‐plot assessment lines demarcating such an inner square as quite free from edge effects.Averages of observed range length and width (ORL and ORW), as reliable measures for the true range size, were determined from the above group of specimens; as a result, the remarkable concept of elliptic range shape was established by regarding ORL as long axis and ORW as short one, and, directly from these averages, the mean range sizes worked out at 0.04 for females and 0.09 for males in acreage which proved to be surprisingly well agreeable with those of isotope‐revealed ranges for voles given byGodfrey (1954) andAmbrose (1969).The catchability for marked voles () was estimated by the maximum likelihood method by use ofJolly's formulae (1965), but that for unmarked ones () was made by the regression census formula; as a result it was shown that the population was clearly of π>p type and that the trap‐experience that voles underwent one month or more ago can make them retain as high catchability as π.
Age structure of six populations of old‐field mice, Peromyscus polionotus
Authors: Dapson Richard W. 
Published: November 2006

SummaryAn accurate age‐estimating technique, based on biochemical changes in eye lens protein, was used to study age structures of six populations of the old‐field mouse, Peromyscus polionotus. A new mathematical procedure permitted quantitative comparisons of these populations. Four inland populations had essentially the same median ages (75–84 days), maximum ages (248–297 days) and relative production rates (56–58% of the surviving population had been born in the 100 days prior to sampling). Approximately 50% of the females were old enough to have weaned a litter. One inland population had a lower median age (49 days), a lower maximum age (181 days) and a higher relative production rate (73%). Relatively fewer females (38%) could have weaned a litter. The single beach population was also different, with higher median age (180 days), and lower relative production rate (2%). All females were old enough to have weaned a litter. Maximum age was essentially the same as for the four similar, inland populations. Factors which may have contributed to observed differences in these populations are discussed.
The change of the distribution pattern of the large weevil, Hyposipalus gigasFabricius (Coleoptera, Rhynchophoridae) within a single generation. A preliminary note
Authors: Furuta Kimito 
Published: November 2006

SummaryThe distribution pattern of adults of the large weevil, Hyposipalus gigas on logs of the Japanese black pine and that of larvae in pine stumps were examined by using the m*−m method (Iwao, 1968). The distribution of adults on logs was contagious, probably due to their response to local heterogeneity of the environment. The larval distribution was also contagious, but there was no significant correlation between the number of larval bores and the stump size. The mortality of young larvae seemed not to be related with the number of larvae per stump, but it was related with the density per unit area of bark surface. There was some sign of inversely density‐dependent or ‘all‐or‐none’ type mortaltiy in the late larval stage.
Rat gastric hydrophobic barrier: Modulation of phosphatidylcholine molecular species by dietary lipids
Authors: Bernhard W. , Postle A. D. , Linck M. , Sewing K. ‐Fr. 
Published: November 2006

AbstractPhospholipids protect the gastric mucosa by forming a proton‐repellent hydrophobic layer on its luminal surface. We have recently shown that two molecular species of phosphatidylcholine (PC), PC16:0/18:1, and PC16:0/18:2, but not PC16:0/16:0, are predominantly released into gastric mucus. We investigated whether these molecular species in mucus are modified by dietary fat. Rats were fed (for three weeks) a diet supplemented with either 10% cod liver, palm, or sunflower oil, or 10% corn starch as a control. In tissue, cod liver oil decreased PC16:0/20:4 and PC18:0/20:4. Cod liver oil and palm oil increased PC16:0/18:1, whereas sunflower oil decreased PC16:0/18:1. Palm oil additionally decreased PC16:0/18:2, whereas the other diets had no effect on PC16:0/18:2. In mucus, however, PC16:0/18:1 and PC16:0/18:2 were not significantly altered by any diet. They were increased over tissue values and comprised 37.6±3.3 and 33.1±1.4 mol% in controls. PC16:0/16:0 was lower in mucus than in mucosa and even decreased by cod liver oil (1.2±0.2 vs. 2.7±0.3 mol%;P<0.01). We conclude that PC16:0/18:1 and PC16:0/18:2 are modified by dietary fat in tissue. In gastric secretions, however, PC16:0/18:1 and PC16:0/18:2 are kept constant and together comprise 70 mol% of the released PC species, whereas PC16:0/16:0 does not play a role for the gastric hydrophobic barrier under any dietary treatment. Additionally, cod liver oil decreases the content of PC16:0/20:4 and PC18:0/20:4 in gastric mucosa, thereby possibly decreasing the formation of eicosanoids.
Changes in lipid composition during metamorphosis of bonefish (Albula sp.) leptocephali
Authors: Padrón David , Lindley Virginia A. , Pfeiler Edward 
Published: November 2006

AbstractDuring metamorphosis of bonefish (Albula sp.) larvae (leptocephali) all energy requirements are provided by breakdown of endogenous compounds, with lipid catabolism accounting for about 80% of total energy production. The principal objective of the present study was to characterize the lipid classes and fatty acids utilized. Analysis of whole‐body lipid content indicated that larvae lost about half (3.6 mg) of their total lipid during the 10‐d period. Percentages of neutral and polar lipid in early metamorphosing larvae were 64.2 and 35.8%, respectively; these values showed little change during metamorphosis, indicating that both lipid classes were catabolized. Triacylglycerols, the principal neutral lipid of all metamorphic stages, decreased by 1.8 mg. accounting for half of the decrease in total lipid. Levels of phosphatidylethanolamine, the principal polar lipid in early larvae, decreased by more than 50% during metamorphosis; levels of phosphatidylcholine, which was not detected in early larvae, increased. Fatty acids showing the largest net decreases, presumedly used as energy sources, were 16∶0 (30.4%), 14∶0 (13.8%), 16∶1n‐7 (12.2%), 20∶5n‐3 (7.7%), 18∶1n‐9 (7.4%), and 18∶4n‐3 (6.9%). Most of 22∶6n‐3, the second most abundant fatty acid of early larvae, was conserved.
Effect of medium‐chain triglycerides on calbindin‐D9k expression in the intestine
Authors: Devlin Angela , Innis Sheila M. , Wall Katharine , Krisinger John 
Published: November 2006

AbstractThese studies determined the effect of the saturated fat source in infant formula on the expression of calbindin‐D9k (CaBP‐9k). Piglets were fed from birth to 8 d with milk or formula containing saturated fatty acids as medium‐chain triglycerides (MCT), coconut oil, palm oil (Palm 1), or synthesized triglycerides with 16∶0 directed to thesn‐2 position (Palm 2). Levels of intestinal CaBP‐9k mRNA were significantly (P<0.01) higher in piglets fed formula with MCT than in piglets fed the other formula or milk; and higher in piglets fed the Palm‐1 than in piglets fed Palm‐2 formula. This is the first evidence that MCT alter piglet intestinal CaBP‐9k mRNA.
Functionalization at the double‐bond region of jojoba oil. 7. Chemical binding of jojoba liquid wax to polystyrene resins
Authors: Binman S. , Belfer S. , Shani A. 
Published: November 2006

AbstractJojoba wax was chemically bonded to a polystyrene matrixvia a stable C‐C covalent bond. This was achieved by binding allyl‐brominated jojoba derivatives to lithiated crosslinked polystyrene‐2% divinylbenzene or XAD‐4 polymeric beads via a nucleophilic substitution reaction. The double‐bond regions in the jojoba wax were preserved. A side reaction that accompanied the nucleophilic substitution was HBr elimination, which produced diene and triene systems in the bound jojoba. Phosphonation and sulfur chlorination at the double bonds of the jojoba wax, bonded to the polystyrene matrix, were also performed.
Changes in phospholipase D experession in soybeans during seed development and germination
Authors: Ryu Stephen B. , Zheng Ling , Wang Xuemin 
Published: November 2006

AbstractActivation of phospholipase D (PLD) has been linked to accumulation of nonhydratable phosphatides and lipid degradation leading to soybean seed deterioration during preharvest and postharvest events. This study examined the changes in PLD activity, protein, and mRNA in soybeans during seed development and germination. RNA blotting analysis indicated that expression of the gene that encodes PLD was highest during the early and middle stages of seed development. However, the amount of PLD activity accumulated per cotyledon reached the highest level in mature seeds. During germination and early seedling growth, PLD mRNA was not detected one day after imbibition, while a significant increase in PLD expression occurred in the cotyledons of three‐ and seven‐day seedlings. Similarly, PLD activity and protein concentration showed little change during the first day of imbibition and increased afterward in three‐ and seven‐day seedlings. These results suggested that expression of PLD is developmentally regulated and that the changes in its amount of activity and protein are controlled primarily at the mRNA level. Immunoblotting analysis further revealed the presence of PLD variants that were associated with specific stages of seed development and seedling growth. The PLD variants present in the cotyledons of mature seeds appeared to be distinct from those observed in the early stage of seed development and in young seedlings.
Lipase‐catalyzed production of biodiesel
Authors: Nelson Lloyd A. , Foglia Thomas A. , Marmer William N. 
Published: November 2006

AbstractLipases were screened for their ability to transesterify triglycerides with short‐chain alcohols to alkyl esters. The lipase fromMucor miehei was most efficient for converting triglycerides to their alkyl esters with primary alcohols, whereas the lipase fromCandida antarctica was most efficient for transesterifying triglycerides with secondary alcohols to give branched alkyl esters. Conditions were established for converting tallow to short‐chain alkyl esters at more than 90% conversion. These same conditions also proved effective for transesterfying vegetable oils and high fatty acid‐containing feedstocks to their respective alkyl ester derivatives.
Antioxidant activity of protein hydrolyzates from aquatic species
Authors: Shahidi Fereidoon , Amarowicz Ryszard 
Published: November 2006

AbstractAntioxidant activity of protein hydrolyzates from capelin (Mallotus villosus) and harp seal (Phoca groenlandica) was examined in a β‐carotene/linoleate model system. Capelin protein hydrolyzates exhibited a significant (P<0.05) antioxidant effect during the entire or a portion of the 120‐min incubation period when added to model systems at 1 to 10‐mg levels per 5 mL of lipid emulsion. However, systems containing 10 mg of seal protein hydrolyzate (SPH) displayed a singificant (P<0.05) prooxidative effect during the experimentation period, but the effect was less pronounced at 5 mg of SPH addition. This effect was reversed to a weak, but significant (P<0.05), antioxidant effect when 1 or 2 mg of SPH were present after 45, 105–120, and 30–120 min of incubation. Two‐dimensional thinlayer chromatographic separation of both hydrolyzates gave spots with antioxidant and prooxidant activites.
Preparation and performance of novel lubricating oil additives derived from 2‐mercaptobenzothiazole
Authors: Wan Yong , Xue Qunji , Cao Lili , Shen Guangqiu 
Published: November 2006

AbstractThree 2‐dialkylaminomethylthiobenzhthiazoles were prepared, and their thermal stability, corrosion‐inhibiting and lubricating characteristics as additives in lubricating oil were evaluated. The novel additives possess higher load‐carrying capacity and better lubricating property.
Eicosapentaenoic acid (20∶5n‐3) from the marine microalgaPhaeodactylum tricornutum
Authors: Cartens M. , Grima E. Molina , Medina A. Robles , Giménez A. Giménez , González J. Ibáñez 
Published: November 2006

AbstractEicosapentaenoic acid (EPA, 20∶5n‐3) was obtained from the marine microalgaePhaeodactylum tricornutum by a three‐step process: fatty acid extraction by direct saponification of biomass, polyunsaturated fatty acid (PUFA) concentration by formation of urea inclusion compounds, and EPA isolation by semipreparative high‐performance liquid chromatography (HPLC). Alternatively, EPA was obtained by a similar two‐step process without the PUFA concentration step by the urea method. Direct saponification of biomass was carried out with two solvents that contained KOH for lipid saponification. An increase in yield was obtained because the problems associated with emulsion formation were avoided by separating the biomass from the soap solution before adding hexane for extraction of insaponifiables. The most efficient solvent, ethanol (96%) at 60°C for 1 h, extracted 98.3% of EPA. PUFA were concentrated by the urea method with a urea/fatty acid ratio of 4∶1 at a crystallization temperature of 28°C and by using methanol and ethanol as urea solvents. An EPA concentration ratio of 1.73 (55.2∶31.9) and a recover yield of 78.6% were obtained with methanol as the urea solvent. This PUFA concentrate was used to obtain 93.4% pure EPA by semipreparative HPLC with a reverse‐phase, C18, 10 mm i.d.×25‐cm column and methanol/water (1% acetic acid), 80∶20 w/w, as the mobile phase. Eighty‐five percent of EPA loaded was recovered, and 65.7% of EPA present inP. tricornutum biomass was recovered in highly pure form by this three‐step downstream process. Alternatively, 93.6% pure EPA was isolated from the fatty acid extract (without the PUFA concentration step) with 100% EPA recovery yield. This two‐step process increases the overall EPA yield to 98.3%, but it is only possible to obtain 20% as much EPA as that obtained by three‐step downstream processing.
Soybean lipoxygenase‐promoted oxidation of free and esterified linoleic acid in the presence of deoxycholate
Authors: Piazza George J. , Foglia Thomas A. , Nuñez Alberto 
Published: November 2006

AbstractLipoxygenase (EC 1.13.11.12) catalyzes the reaction between oxygen and polyunsaturated fatty acids to give fatty acid hydroperoxides. Recent work showed that soybean lipoxygenase 1 can oxidize diacylglycerols when deoxycholate is present in the reaction medium. Conditions were sought to maximize 1,3‐dilinolein oxidation with a commercial soybean lipoxygenase preparation. It was found that dilinolein was oxidized most rapidly in a multicomponent buffer medium that contained 10 mM deoxycholate between pH 8 and 9. When dilinolein oxidation was conducted in the individual components of the multicomponent buffer, the oxidation rate decreased two‐ to threefold. Addition of 0.2 M NaCl to one of the components, Tricine buffer, caused a twofold increase in the oxidation rate, demonstrating that high ionic strength is a major factor promoting rapid oxidation in the multicomponent buffer. In the deoxycholate multicomponent buffer, the order of reactivity toward oxidation was monolinolein>methyl linoleate≈ linoleic acid>dilinolein. Competition experiments in which mixtures of the substrates were presented simultaneously to lipoxygenase in the presence of deoxycholate showed that linoleic acid was the most reactive substrate. When no surfactant was present or when the surfactant was Tween 20, linoleic acid was the most rapidly oxidized substrate. Overall, the results demonstrate that monolinolein and methyl linoleate are just as reactive, or more so, as linoleic acid to oxidation by lipoxygenase under specified reaction conditions. In competition experiments, linoleic acid oxidation predominates, probably because its free carboxyl functionality allows it to be preferentially bound to the active site of lipoxygenase.
Enzymatic modification of evening primrose oil: Incorporation of n−3 polyunsaturated fatty acids
Authors: Akoh Casimir C. , Jennings Brenda H. , Lillard Dorris A. 
Published: November 2006

AbstractImmobilized lipase SP435 fromCandida antaractica was used as a biocatalyst for the modification of the fatty acid composition of evening primrose oil by incorporating n−3 polyunsaturated fatty acid (PUFA) and eicosapentaenoic acid (EPA). Transesterification (ester‐ester interchange) was conducted in organic solvent or without solvent, with EPA ethyl ester (EEPA) as the acyl donor. Products were analyzed by gas‐liquid chromatography (GLC). After 24‐h incubation in hexane, the fatty acid composition of evening primrose oil was markedly changed to contain up to 43% EPA. The amount of 18:2n−6 PUFA was reduced by 32%, and the saturated fatty acid content was also reduced. The effects of incubation time, molar ratio, enzyme load, and reaction medium on mol% EPA incorporation were also studied. Generally, as the incubation time (up to 24 h), molar ratio, and enzyme load increased, EPA incorporation also increased. Evening primrose oil, containing EPA and γ‐linolenic acid (18:3n−6) in the same glycerol backbone, was successfully produced and may be more beneficial for certain applications than unmodified oil.
Oil content and fatty acid composition of commercially important Turkish fish species
Authors: Üstün G. , Akova A. , Dandik L. 
Published: November 2006

AbstractThe oil content and fatty acid composition of commercially important Turkish fish species (anchovy,Engraulis encrasicholus; freshwater rainbow trout,Salmo gairdneri; and cultured salmon,S. salar) were determined. Palmitic (16∶0), palmitoleic (16∶1), oleic (18∶1), and docosahexaenoic (22∶6) acids were the most abundant fatty acids in all species. Eicosapentaenoic acid (20∶5) was twice as high in the anchovy oil as in the rainbow trout and salmon oils. Significant quantities of linoleic acid (18∶2) and docosahexaenoic acids (22∶6) were found in both rainbow trout and salmon samples. The individual fatty acid data obtained from rainbow trout and salmon were similar to each other. All three fish species contain high levels of n‐3 polyunsaturated fatty acids and would be suitable for inclusion in the formulation of low‐fat highly unsaturated diets.
Contrasts in the surface activity of polyoxypropylene and polyoxybutylene‐based block copolymer surfactants
Authors: Nace V. M. 
Published: November 2006

AbstractPrevious studies have shown that polyoxybutylene surfactant hydrophobes are less polar than polyoxypropylene hydrophobes. Polyoxyalkylene hydrophobes can be modified by ethoxylation to give terminal polyoxyethylene block hydrophilic groups. Polyoxybutylene/polyoxyethylene copolymer surfactants exhibit differentiated interfacial tensions, and wetting and foaming properties when compared to structurally equivalent polyoxypropylene/polyoxyethylene copolymers. There have been no reported comparisons, however, of polyoxybutylene/polyoxyethylene copolymers and polyoxypropylene/polyoxyethylene analogues in terms of fundamental parameters, such as critical micelle concentration, area per molecule at the interface, efficiency, and effectiveness. In one phase of this work, four polyoxybutylene/polyoxyethylene block copolymer surfactants were compared to structurally analogous polyoxypropylene/polyoxyethylene materials. Findings showed that polyoxybutylene/polyoxyethylene copolymers exhibited enhanced cotton wetting and lower surface and interfacial tensions compared to polyoxypropylene/polyoxyethylene analogues. Polyoxybutylene‐based surfactants were typically one order of magnitude better in their ability to reduce surface tension at interface saturation. Polyoxybutylene/polyoxyethylene copolymers pack more efficiently at the interface, as evidenced by a smaller area per molecule at the interface. Critical micelle concentration values were also lower for polyoxybutylene/polyoxyethylene copolymers. A second phase of experiments focused on the surface activity of polyoxypropylene/polyoxyethylene triblock copolymers with higher molecular weight hydrophobes. Enhanced surface activity was found when compared to lower‐molecular weight polyoxypropylene/polyoxyethylene copolymers.