bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Iron Connections Between Desert Dust, Ocean Biogeochemistry, and Climate
Authors: Jickells T. D. , An Z. S. , Andersen K. K. , Baker A. R. , Bergametti G. , Brooks N. , Cao J. J. , Boyd P. W. , Duce R. A. , Hunter K. A. , Kawahata H. , Kubilay N. , laRoche J. , Liss P. S. , Mahowald N. , Prospero J. M. , Ridgwell A. J. , Tegen I. , Torres R.
Published: March 2005

The environmental conditions of Earth, including the climate, are determined by physical, chemical, biological, and human interactions that transform and transport materials and energy. This is the “Earth system”: a highly complex entity characterized by multiple nonlinear responses and thresholds, with linkages between disparate components. One important part of this system is the iron cycle, in which iron-containing soil dust is transported from land through the atmosphere to the oceans, affecting ocean biogeochemistry and hence having feedback effects on climate and dust production. Here we review the key components of this cycle, identifying critical uncertainties and priorities for future research.
Simultaneous Tomography and Diffraction Analysis of Creep Damage
Authors: Pyzalla A. , Camin B. , Buslaps T. , Di Michiel M. , Kaminski H. , Kottar A. , Pernack A. , Reimers W.
Published: March 2005

Creep damage by void nucleation and growth limits the lifetime of components subjected to loading at high temperatures. We report a combined tomography and diffraction experiment using high-energy synchrotron radiation that permitted us to follow in situ void growth and microstructure development in bulk samples. The results reveal that void growth versus time follows an exponential growth law. The formation of large void volumes coincides with texture evolution and dislocation density, reaching a steady state. Creep damage during a large proportion of sample creep life is homogeneous before damage localization occurs, which leads to rapid failure. The in situ determination of void evolution in bulk samples should allow for the assessment of creep damage in metallic materials and subsequently for lifetime predictions about samples and components that are subject to high-temperature loading.
A Late Jurassic Digging Mammal and Early Mammalian Diversification
Authors: Luo Zhe-Xi , Wible John R.
Published: March 2005

A fossil mammal from the Late Jurassic Morrison Formation, Colorado, has highly specialized teeth similar to those of xenarthran and tubulidentate placental mammals and different from the generalized insectivorous or omnivorous dentitions of other Jurassic mammals. It has many forelimb features specialized for digging, and its lumbar vertebrae show xenarthrous articulations. Parsimony analysis suggests that this fossil represents a separate basal mammalian lineage with some dental and vertebral convergences to those of modern xenarthran placentals, and reveals a previously unknown ecomorph of early mammals.
Selection equilibrium for hatchery and wild spawning fitness in integrated breeding programs
Authors: Goodman Daniel
Published: March 2005

Some salmon hatchery programs intentionally integrate the wild and hatchery population by taking naturally spawned fish as some fraction of the broodstock and allowing hatchery progeny to constitute some fraction of the adults spawning in the wild. This circumvents some ecological concerns about the effects of hatchery fish on the "wild" population while still reaping some of the benefits of increased potential for harvest, but it increases some genetic concerns. Here, we model phenotypic evolution in the integrated population to investigate the effects on natural spawning fitness at the joint selection and demographic equilibrium. We find a potential, but not a certainty, depending on quantitative aspects of the management interacting with biological characteristics of the stock, for substantial erosion of natural spawning fitness, compared with the original wild population, including the possibility of runaway selection driving natural spawning fitness effectively to zero. The vulnerability to such evolutionary deterioration increases with the magnitude of the contribution of hatchery breeding to the total production and increases with harvest. The response of the selection equilibrium to increasing contribution of hatchery progeny to the broodstock can exhibit a catastrophic discontinuity.
δ15N in riverine food webs: effects of N inputs from agricultural watersheds
Authors: Anderson Caroline , Cabana Gilbert
Published: March 2005

We examined the use of the natural abundance of nitrogen stable isotopes (δ15N) as a tracer of anthropo genic perturbations of the nitrogen (N) cycle at the watershed scale in 82 river sites draining 13 watersheds in the St. Lawrence Lowlands in Quebec. Mean δ15N values of aquatic primary consumers varied greatly among sites (+2 to +15), most of this variation (88%) being attributable to site effects. Variation in δ15N values among functional feeding groups of primary consumers within sites was comparatively lower (<1). Within watersheds, δ15N values of primary consumers (and organisms of higher trophic levels) tracked longitudinal changes in the percentage of agricultural area. Overall, the percentage of total watershed area under agriculture explained up to 69% of the variation in mean primary consumer δ15N values. Similar positive correlations were observed for predatory invertebrates and non-piscivorous fish. In general, our results show that δ15N in riverine food webs reacts strongly to spatial patterns in the intensity of N inputs related to agricultural land use.
Monte Carlo evaluation of a nonlinear regression estimator for aggregated lengthweight data
Authors: Lee Yong-Woo , Sampson David B
Published: March 2005

Parameters of fish lengthweight relationships (W = aLb) are usually estimated by applying linear regression to log-transformed length and weight values, but measuring individual weights is time-consuming and expensive. Often, length and weight data are available as sets of length measurements and aggregated sample weights, and the aggregate average weight of a sample can be expressed as the average of the weights predicted for the individual fish lengths. This study evaluated the feasibility of applying nonlinear regression to aggregated lengthweight data. Experiments with simulated random lengthweight data demonstrated that the estimates of parameter b appear to be unbiased and the estimates of a are right-skewed and biased. Further, the estimates of ln(a) and b are almost perfectly correlated. The precision and accuracy of the estimates were greatly influenced by the number of aggregate samples but were relatively unaffected by the number of fish in each sample. An additional experiment showed that the residuals from the regression can be used to detect small changes in the lengthweight parameters.
Bayesian removal estimation of a population size under unequal catchability
Authors: Mäntyniemi Samu , Romakkaniemi Atso , Arjas Elja
Published: March 2005

We introduce a Bayesian probability model for the estimation of the size of an animal population from removal data. The model is based on the assumption that in the removal sampling, catchability may vary between individuals, which appears to be necessary for a realistic description of many biological populations. Heterogeneous catchability among individuals leads to a situation where the mean catchability in the population gradually decreases as the number of removals increases. Under this assumption, the model can be fitted to any removal data, i.e., there are no limitations regarding the total catch, the number of removals, or the decline of the catch. Using a published data set from removal experiments of a known population size, the model is shown to be able to estimate the population size appropriately in all cases considered. It is also shown that regardless of the statistical approach, a model that assumes equal catchability of individuals generally leads to an underestimation of the population. The example indicates that if there is only vague prior information about the variation of catchability among individuals, a very high number of successive removals may be needed to correctly estimate the population size.
Bottom-up limitation of a stream salamander in a detritus-based food web
Authors: Johnson Brent R , Wallace J Bruce
Published: March 2005

The indirect effects that resources can have on higher trophic levels remain poorly understood for detritus-based ecosystems. Our objective was to examine effects of long-term terrestrial litter exclusion on a larval salamander, Eurycea wilderae, in a detritus-based stream. After 4 years of exclusion treatment, we conducted a markrecapture study and analyzed gut contents of E. wilderae larvae in the litter exclusion reach, a reach downstream of treatment, and in a reference stream. Eurycea wilderae growth rate (per day), density (individuals per square metre), biomass (milligrams ash-free dry mass per square metre), and production (milligrams ash-free dry mass per square metre per year) were all significantly reduced in the litter exclusion reach. Reduced density in the treatment reach was likely due to elevated hatchling drift driven by reduced prey availability. Larvae from the treatment reach had fewer prey items per gut than larvae in the reference stream and their diet consisted of fewer copepods but more midge larvae, nematodes, and terrestrial insects. The reach downstream of treatment was intermediate between reference and litter exclusion reaches for most measured parameters, indicating residual effects of upstream treatment. Our results provide the first comprehensive evidence of bottom-up limitation of a vertebrate predator in a detritus-based ecosystem and further demonstrate the importance of the terrestrialaquatic linkage.
Modeling feeding processes: a test of a new model for sea bream (Sparus aurata) larvae
Authors: Lika Konstadia , Papandroulakis Nikos
Published: March 2005

An organism's feeding rate is governed by constraints imposed by processes associated with consumption. We present a general feeding model that incorporates encounter, successful pursuit, handling, and digestion in one functional representation where we treat digestion as a parallel process. The model produces type II functional response curves. However, the asymptotic maximum feeding rate is determined by the sum of the time spent for handling and digesting a prey minus the gain in time, since the digestion process is parallel to the handling process. We use our model in combination with existing models of encounter, successful pursuit, and digestion to evaluate the feeding rate of fish larvae. We test the model against experimental data for sea bream (Sparus aurata) larvae and find a very close quantitative correspondence between predictions and experiments. Sensitivity analysis shows that for the early developmental stages, the model is sensitive to parameters related to the visual and locomotion abilities of larvae to detect and capture the prey. Later, when they establish these abilities, the choice of accepting or not the prey becomes more important.
Mercury methylation in the hypolimnetic waters of lakes with and without connection to wetlands in northern Wisconsin
Authors: Eckley C S , Watras C J , Hintelmann H , Morrison K , Kent A D , Regnell O
Published: March 2005

Rates of Hg methylation and demethylation were measured in anoxic hypolimnetic waters of two pristine Wisconsin lakes using stable isotopes of Hg as tracers. One of the lakes is a clear-water seepage lake situated in sandy terrain with minimal wetland influence. The other is a dark-water lake receiving channelized inputs from a relatively large terrestrial wetland. Methyl mercury (MeHg) accumulated in the anoxic hypolimnia of both lakes during summer stratification, reaching concentrations of 0.8 ng·L1in the clear-water lake and 5 ng·L1in the dark-water lake. The stable isotopic assays indicated that rate constants of Hg(II)methylation (Km) ranged from 0.01 to 0.04·day1in the clear-water lake and from 0.01 to 0.09·day1in the dark-water lake, depending on the depth stratum. On average, Kmwas threefold greater in the dark-water lake. Hypolimnetic demethylation rate constants (Kdm) averaged 0.03·day1in the clear-water lake and 0.05·day1in the dark-water lake. These methylation rates were sufficient to account for the observed accumulation of MeHg in hypolimnetic water during summer in both lakes. Despite substantial export of MeHg from the wetland to the dark-water lake, our study indicates that in-lake production and decomposition of MeHg dominated the MeHg cycle in both lakes.
In situ measurement of tissue turnover and energy conversion efficiencies in lake trout (Salvelinus namaycush) using a novel toxicokinetic approach
Authors: Paterson Gordon , Huestis Susan Y , Whittle D Michael , Drouillard Kenneth G , Haffner G Douglas
Published: March 2005

We determined polychlorinated biphenyl (PCB) elimination patterns in lake trout (Salvelinus namaycush) from Lake Ontario using biomonitoring data collected from 1977 to 1993. The in situ elimination rates of these persistent pollutants were found to describe tissue turnover rates in lake trout. A model relating tissue turnover rates and endogenous energy conversion efficiencies revealed that chemical elimination in larger organisms is primarily regulated by food limitation and bioenergetic mechanisms rather than chemical kinetics. Lake trout approximately 2500 g and larger were observed to have higher PCB elimination rates than smaller fish as a result of increased lipid mobilization to supplement metabolic demands due to increased time spent foraging. This study concludes that the growth and production of large predators in Lake Ontario are regulated by the bioenergetic constraints of searching for prey in a food-limited environment. We also demonstrate that persistent organic pollutant kinetics can describe the proportion of endogenous energy required to support metabolism and production, thus providing important in situ measurements of bioenergetic processes.
Effects of an increase in large wood on abundance and survival of juvenile salmonids (Oncorhynchus spp.) in an Oregon coastal stream
Authors: Johnson Steven L , Rodgers Jeffrey D , Solazzi Mario F , Nickelson Thomas E
Published: March 2005

We examined the effect of an increase in large wood on the summer population size, smolt abundance, and freshwater survival of steelhead (Oncorhynchus mykiss), coastal cutthroat trout (Oncorhynchus clarki clarki), and coho salmon (Oncorhynchus kisutch). We examined these parameters for five brood years prior to the addition of wood and five brood years after in Tenmile Creek, a direct ocean tributary on the Oregon coast. Over the same time frame, a nearby reference stream, Cummins Creek, was also sampled for the same parameters. The input of large wood into Tenmile Creek resulted from a planned habitat restoration project in 1996 and an unplanned addition of wood from a winter storm the same year. Steelhead smolt abundance, steelhead freshwater survival, and coho salmon freshwater survival increased in Tenmile Creek after the input of large wood. Steelhead age-0+ summer populations and steelhead smolt populations increased in the reference stream, although steelhead freshwater survival did not. Coho salmon populations remained unchanged in the reference stream. Our results illustrate the potential shortcomings of the before-after-control-impact study design under field conditions and the potential for misinterpreting results had we employed a more modest sampling plan.
Bacterial response to dissolved organic matter affects resource availability for algae
Authors: Klug Jennifer L
Published: March 2005

In aquatic systems, the presence of colored dissolved organic matter (DOM) may affect algal growth in numerous ways. This paper focuses on the effects of DOM on resource availability. DOM contains nitrogen and phosphorus, which may become available following microbial or photochemical degradation. Also, addition of DOM may stimulate bacterial growth, which in turn may change the availability of nitrogen, phosphorus, and inorganic carbon to algae. Experiments conducted in a moderately colored lake showed that the effect of DOM on algal growth depended on the amount of nutrients present in the peat extract and on bacterial response to DOM. There was evidence for competition for phosphorus between algae and bacteria in some treatments. In addition, when both bacteria growth and algal growth were high, bacterial respiration of DOM alleviated algal carbon limitation by providing algae with an inorganic carbon source. Thus, the degree to which bacteria are stimulated by the addition of DOM will affect the amount of phosphorus and inorganic carbon available for algal growth. These results suggest that part of the difficulty in predicting algal response to changes in DOM and nutrient concentration may be due partially to variability in bacterial responses.
Theoretical studies on the absorption and luminescent properties of a series of derivatives of 1,3-diphenyl-5-pyrene-2-yl-4,5-dihydro-1H-pyrazole
Authors: Liu Xiao-Juan , Feng Ji-Kang , Ren Ai-Min , Zhou Xin , Cheng Hong
Published: March 2005

The absorption and emission spectra for a series of substituted 1,3-diphenyl-5-pyrene-2-yl-4,5-dihydro-1H-pyrazole (DPPyP) molecules are computed by TDDFT methods. The solvent effect is modeled using the self-consistent reaction field (SCRF) method with Tomasi's polarized continuum model (PCM). The ground-state geometries were optimized by the HartreeFock method with the 6-31G basis set (and also with 3-21G* for molecule A) (HF/6-31G), and the lowest singlet excited-state geometries were optimized at the ab initio CIS level with the 6-31G basis set (CIS/6-31G). The calculated results indicate that the TDDFT method can reproduce the experimental values. We consider the effects of different basis sets on the optimization of the ground-state geometries. Specially, some insights on the differences observed for these compounds in changing the substituted donors (H, CH3, and NH2) and acceptor group (CN) are given; the results indicate that introduction of the donor groups will lead emission to be red-shifted, while introduction of the acceptor will induce the emission to be blue-shifted, which provides useful information for modulating light-emitting material colors.Key words: absorption and emission, TDDFT, CIS, SCRFPCM.
Mild, efficient, and chemoselective dehydrogenation of 2-imidazolines, bis-imidazolines, and N-substituted-2-imidazolines with potassium permanganate supported on montmorillonite K-10
Authors: Mohammadpoor-Baltork Iraj , Abdollahi-Alibeik Mohammad
Published: March 2005

Different types of 2-imidazolines, bis-imidazolines, and N-substituted-2-imidazolines are efficiently oxidized to their corresponding imidazoles with potassium permanganate (KMnO4) supported on montmorillonite K-10 under very mild conditions. The procedure is very simple and no strict conditions were required. Selective dehydrogenation of 2-alkyl-2-imidazolines in the presence of 2-aryl-2-imidazolines is a noteworthy advantage of this method and can be considered as a useful practical achievement in these reactions.Key words: 2-imidazolines, imidazoles, dehydrogenation, potassium permanganate, montmorillonite K-10.
Conformational study of internally retrograde and quasi-retrograde molecules  An ab initio and DFT study
Authors: Zamora Miguel A , Santágata Luis N , Masman Marcelo F , Bombasaro José A , Freile Mónica L , Enriz Ricardo D
Published: March 2005

A conformational study of the symmetrical and nonsymmetrical homologue series was carried out. In this study, ab initio (RHF/3-21G and RHF/6-31G(d)) and density functional theory (B3LYP/6-31G(d)) calculations were performed. The presence of two symmetrical aromatic systems (identical or not) reduces notably the conformational possibilities of these compounds. Our results indicate that RHF/3-21G calculations are sufficient to use in a preliminary form. However, from our results it is prudent to use this technique only for a preliminary or exploratory conformational analysis. Thus, at least, the HF level of theory in conjunction with more extended basis sets and the inclusion of electron correlation appear to be necessary to confirm critical points at the potential energy hyper surfaces (PEHSs) and to assign the conformational preferences of these compounds. In the present paper, we report a complete and comprehensive picture of the conformational intricacies of the compounds with a small flexible connecting chain (n = 15). In addition, an "educated guess" for the conformational behaviour of large-size homologues (n = 610) is also reported.Key words: ab initio and DFT calculations, conformational study, homologue series.
Kinetic and spectroscopic studies on α- and β-cyclodextrin rotaxanes with (µ-N,N′- bis(4-pyridinylmethylene)-α,ω-alkanediimine)bis[pentacyanoferrate(II)] threads
Authors: Jin Victor X , Macartney Donal H , Buncel Erwin
Published: March 2005

[2]Pseudorotaxanes have been prepared by threading N,N′-bis(4-pyridinylmethylene)-1,2-ethanediimine (L2), -1,4-butanediimine (L4), and -1,6-hexanediimine (L6) ligands through α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), and have subsequently been converted to the corresponding [2]rotaxane species by coordinating bulky [Fe(CN)5]3 end groups. The stability constants for the [2]pseudorotaxanes were determined by 1H NMR chemical shift titrations and increase with the polymethylene chain length n. The rate constants for both the formation of the [Fe(CN)5(Ln)]3 complexes from the [Fe(CN)5OH2]3 ion and Ln, and the rate constants for the dissociation of Ln from the metal complexes, exhibit significant diminutions in the presence of α- and β-CD, owing to inclusions of the free and coordinated ligands, respectively. The lability of the iron(II)pyridine bonds also permits the spontaneous self-assembly of the [2]rotaxane upon the addition of cyclodextrin to the iron dimer complexes. The mechanism for this process involves the rate-determining dissociation of a [Fe(CN)5]3 unit from [(NC)5Fe(Ln)Fe(CN)5]6, followed by CD inclusion of the Ln ligand to form a semirotaxane, and subsequent recomplexation by the [Fe(CN)5OH2]3 ion. Key words: cyclodextrins, rotaxanes, pentacyanoferrate(II), ligand substitution, kinetics.
Dew points of quaternary ethane + carbon dioxide + water + methanol mixtures  Measurement and modelling
Authors: Jarne C , Blanco S T , Avila S , Berro C , Otín S , Velasco I
Published: March 2005

Dew points have been measured for eight ethane + carbon dioxide + water + methanol mixtures at pressures from 0.11 to 2.17 MPa and temperatures from 249.0 to 288.7 K. The results are analysed in terms of a predictive excess-function equation of state (EF-EOS) method based on the zeroth approximation of Guggenheim's reticular model. This method can be used to adequately predict the dew points of the mixtures in the temperature and pressure ranges used in the present study. In fact, the model reproduces the experimental dew point temperature data with ≤3.1 K average absolute deviation.Key words: dew point, equation of state, excess function.
Substituent effects of the cycloaddition reaction of 7-substituted 5H-benzocycloheptenes with singlet oxygen and the chemistry of the benzocycloheptene endoperoxides
Authors: Güney Murat , Ceylan Zeynep Çelik , Daştan Arif , Balci Metin
Published: March 2005

The cycloaddition reaction of 7-substituted 5H-benzocycloheptenes with singlet oxygen and the chemistry of the obtained endoperoxides were investigated. Reaction of carboethoxy-substituted endoperoxide with NEt3 gave a mixture of products; hydroxyketone, diketone, and carboethoxy-substituted ketoenol tautomers, whereas the reaction of methyl-substituted endoperoxide only formed a diketone under the same reaction conditions. Thermolysis, thiourea, and CoTPP reactions of the endoperoxides were also studied. The reaction mechanism and electronic effect of substituents were discussed.Key words: benzocycloheptene, photooxygenation, endoperoxides, rearrangement, CoTPP.
Review on green chemistry  Suzuki cross coupling in aqueous media
Authors: Franzén Robert , Xu Youjun
Published: March 2005

The Suzuki cross-coupling reaction is a very efficient, reliable, and environmentally friendly method for the introduction of novel carboncarbon bonds into molecules. This review summarizes recent advances in the use of the reaction in aqueous media with a focus on different types of ligands and the ligandless protocols currently in use. Several synthetic targets for the reaction have been mentioned. The work summarizes recent results from studies on asymmetric Suzuki reactions performed in organic  aqueous mixed solvents.Key words: Suzuki reaction, green chemistry, metal-catalyzed cross-coupling reactions, aqueous synthesis media.
Hawthorn: Potential Roles in Cardiovascular Disease
Authors: Chang Wei-Tien , Dao Jenny , Shao Zuo-Hui
Published: March 2005

Hawthorn (Crataegus) may play a role in the prevention and treatment of cardiovascular diseases such as hypertension, hyperlipidemia, and in particular, congestive heart failure. Evidence is accumulating that hawthorn may induce anti-ischemia/reperfusion-injury, anti-arrhythmic, hypolipidemic and hypotensive effects. These beneficial effects may in part be due to the presence of antioxidant flavonoid components. While a number of studies have been performed to evaluate the clinical efficacy of hawthorn, an international, multi-center, prospective clinical study including a large number of New York Heart Association (NYHA) class II/III heart failure patients is ongoing to test hawthorn's long-term therapeutic effects. Further clinical trials as well as pharmacokinetic and mechanistic studies are needed to explore and confirm its effectiveness, safety and pharmacological mechanism.
Effect of Kami-kihi-to (Jia-Wei-Gui-Pi-Tang) for Experimental Osteopenia
Authors: Kanai Shigeyuki , Taniguchi Norimasa , Higashino Hideaki
Published: March 2005

In order to examine the effects of Kami-kihi-to (KKT or Jia-Wei-Gui-Pi-Tang) on osteopenia, we measured bone mineral density using computed X-ray absorptometry and monitored metabolism and bone tissue in an ovariectomized (OVX) rat model.

Bone mineral density was significantly lower in the OVX group than in normal group 3 months after ovariectomy. However, the bone mineral density of the OVX group administered KKT was clearly higher than that of the untreated OVX group.

Locomotor activity was regular in the normal group and in the OVX groups before administration of KKT. After 6-month administration of KKT, in OVX groups, the pattern of locomotor activity became diphasic with clear active and resting phases, as was also observed in the normal group. The locomotor activity did not decrease in the OVX groups after administration of KKT. At 6 months, the continuity of the trabecular bone was higher in the OVX group administered KKT than in the untreated OVX group. These results indicate that KKT improved the menopausal symptoms and increased the locomotor activity of the OVX group, thereby increasing bone mineral density.
The Neuroprotective Effects of BNG-1: A New Formulation of Traditional Chinese Medicines for Stroke
Authors: Cheng Fong-Chi , Chen Wen-Long , Wei Jiann-Wu , Huang Ken-Shung , Yarbrough George G.
Published: March 2005

BNG-1, a novel mixture of traditional Chinese medicines with a long history in the treatment of stroke, exhibited acute neuroprotection effect on rats with middle cerebral artery occlusion (MCAO). Anti-ischemic effects were seen in both animals receiving BNG-1 before the ischemic insult as well as in animals receiving the drug formulation after surgical occlusion of the artery. Anti-thrombic activity was seen in vitro to inhibit arachidonic acid-induced platelet aggregation and in vivo to prolong bleeding time in mice. BNG-1 was also found to inhibit several phosphodiesterase (PDE) isoforms with potency order of the following rank: PDE 1>PDE 3>PDE 6>PDE 2>PDE 4>PDE 5. Other pre-clinical results and emerging clinical data coupled with the present findings suggest that BNG-1 may be a safe and effective therapy for both the prevention and treatment of cerebral stroke. Moreover, the fundamental cellular mechanism underlying its therapeutic effects may result from phosphodiesterase inhibition.
Anti-hepatitis C Virus Effect of Citrus Unshiu Peel and Its Active Ingredient Nobiletin
Authors: Suzuki Megumi , Sasaki Kenroh , Yoshizaki Fumihiko , Fujisawa Min , Oguchi Katsuji , Cyong Jong-Chol
Published: March 2005

We investigated the effects of water and ethyl acetate extracts of Citrus unshiu peel (Aurantii Nobilis pericarpium) on hepatitis C virus (HCV) absorption in MOLT-4 cells (a human lymphoblastoid leukemia cell line). By reverse transcription polymerase chain reaction (RT-PCR), we showed that both the ethyl acetate layer of Citrus unshiu peel extract and fraction 7 decreased HCV absorption in MOLT-4 cells. Furthermore, we demonstrated that 3′,4′,5,6,7,8-hexamethoxyflavone (nobiletin) is the active ingredient that markedly inhibited HCV infection in MOLT-4 cells.
The Effects of Ananas comosus L. Leaves on Diabetic-Dyslipidemic Rats Induced by Alloxan and a High-Fat/High-Cholesterol Diet
Authors: Xie Weidong , Xing Dongming , Sun Hong , Wang Wei , Ding Yi , Du Lijun
Published: March 2005

The aim of this study is to demonstrate the effects of Ananas comosus L. leaves on diabetic-dyslipidemic rats. Hypoglycemic and hypolipidemic activities of the ethanolic extract of Ananas comosus L. leaves (EEACL) were evaluated in normal and alloxan-induced diabetic rats by oral glucose tolerance test and an olive oil load test. Anti-diabetic, anti-hyperlipidemic and anti-oxidative activities of EEACL were also investigated in diabetic-dyslipidemic rats induced by alloxan and a high-fat/high-cholesterol diet. EEACL at the dose of 0.40 g/kg significantly inhibited the increase in blood glucose in diabetic rats in oral glucose tolerance test, but did not cause any hypoglycerimic activity in normal rats. It also significantly inhibited the increase in postprandial triglycerides (TG) levels in both normal and diabetic rats in olive oil load test. After 15 days of treatment of diabetic dyslipidemic rats, EEACL significantly decreased blood glucose (-51.0%, P<0.01), TG (-50.1%, P<0.01), TC (-23.3%, P<0.01), LDL-c (-47.9%, P<0.01) and glycated albumin (-25.4%, P<0.01) levels, significantly increased serum high-density lipoprotein cholesterol levels (66.2%, P<0.01) and prevented lower body weight of diabetes (11.8%, P<0.05), significantly lowered lipid peroxidation productions of blood (-27.8%, P<0.01), brain (-31.6%, P<0.05), liver (-44.5%, P<0.01) and kidneys (-72.2%, P<0.05) compared with those in untreated diabetic dyslipidemic rats. These data suggest that EEACL has anti-diabetic, anti-dyslipidemic and anti-oxidative activities, which may be developed into a new plant medicine for treatment of diabetes and its complications.
Effects of Medicinal Herb Tea on the Smoking Cessation and Reducing Smoking Withdrawal Symptoms
Authors: Lee Ho-Jae , Lee Jae-Hwan
Published: March 2005

Medicinal herbs (21 species) were screened for the antioxidant activity and nicotine degradation activity (NDA) in vitro. Eleven of them with higher antioxidant activity and NDA were selected for preparation of the medicinal herb tea (MHT) and the effects of MHT on smoking cessation and reducing smoking withdrawal symptoms were evaluated in 100 male human smokers.

Among these medicinal herbs, Eugenia aromaticum and Astragalus membranaceus Bunge showed the highest antioxidant activity ( IC 50 of 30.0 μg/mL) and NDA (1.81), respectively. MHT showed relatively high antioxidant activity ( IC 50 of 50.6 μg/mL) and NDA (1.23). The urinary cotinine level, a metabolite of nicotine, increased in the first 2 weeks and greatly decreased from the 2nd to 4th week in the MHT taking group, which indicates that MHT accelerates the conversion of nicotine into cotinine. Human groups taking MHT for 4 weeks underwent reduced smoking withdrawal symptoms compared to the non-MHT taking subjects, and 38% of subjects taking MHT succeeded in smoking cessation, while only 12% of non-MHT taking subjects succeeded in quitting smoking.
MODELING MEMORY OF ECONOMIC AND FINANCIAL TIME SERIES
Authors: ROBINSON PETER M.
Published: March 2005

Much time series data are recorded on economic and financial variables. Statistical modeling of such data is now very well developed, and has applications in forecasting. We review a variety of statistical models from the viewpoint of "memory", or strength of dependence across time, which is a helpful discriminator between different phenomena of interest. Both linear and nonlinear models are discussed.
HOW EFFECTIVE ARE PRONATALIST BENEFITS? A LITERATURE SURVEY AND A STUDY ON SINGAPORE'S QUALIFIED CHILD RELIEF
Authors: PARK CHEOLSUNG
Published: March 2005

This paper reviews the existing literature on impacts of pronatalist benefits on fertility in various countries, and estimates the impact of the Qualified Child Relief (QCR) on the total fertility rate (TFR) of Singapore. The studies surveyed in this paper generally find that pronatalist incentives contribute to raising the fertility rate, but only to a limited extent. In Singapore, a 1% increase in the QCR is estimated to increase the TFR by 0.1–0.2%. Singapore's fertility rate is also found to be positively correlated with men's earnings and the infant mortality rate, while negatively correlated with women's earnings and the unemployment rate. Evidence that the New Population Policy of 1987 has been effective in raising the fertility rate is also found.
VERTICAL PRODUCT INNOVATION AND PARALLEL IMPORTS
Authors: LI CHANGYING
Published: March 2005

In this paper, we develop a model of endogenous R&D in vertical product innovation by an original manufacturer facing Bertrand competition from parallel importer(s). We show that if parallel imports are prohibited among the distributors' countries and there is at least one country other than the manufacturer's homeland in which there is only one distributor, then allowing reimports reduces the manufacturer's incentive to innovate. Otherwise, permitting reimports has no effect on the manufacturer's incentive to invest in R&D. Moreover under the assumption of Bertrand competition, either delegating more than one distributor in each country outside the manufacturer's homeland or allowing parallel imports among the distributors' countries enables the manufacturer to maximize his total profit regardless of whether innovation is successful.
TESTING FOR REGIME SWITCHING IN SINGAPOREAN BUSINESS CYCLES
Authors: BREUNIG ROBERT , STEGMAN ALISON
Published: March 2005

We examine a Markov-Switching model of Singaporean GDP using a combination of formal moment-based tests and informal graphical tests. The tests confirm that the Markov-Switching model fits the data better than a linear, autoregressive alternative. The methods are extended to allow us to identify precisely which features of the data are better captured by the nonlinear model. The methods described here allow model selection to be related to the intended use of the model.
PRICE CONTROL REGULATION OF PRIVATIZED UTILITIES IN THE UNITED KINGDOM: WHAT LESSONS FOR THE DEVELOPING ASIAN NATIONS?
Authors: HOSSAIN MOAZZEM
Published: March 2005

Privatization of public utilities in the United Kingdom has been the key vehicle for attaining further improvement in living standards since the mid-1980s. The United Kingdom was the first of the developed nations to privatize public utilities in 1984 when it sold British Telecom (BT). In subsequent years, almost all developed and developing nations followed suit. Simultaneously, the UK's privatization initiatives established independent regulatory agencies to oversee the performance of the newly privatized natural monopolies to protect all the parties (consumers, operators and government) from any adverse consequences of privatization. Most importantly, the regulators oversee and manage the affects of privatization on price increases. This paper investigates the price control regulation of privatized utilities in the UK with a view to gaining further lessons from these experiences for the developing Asian nations where privatization of utilities is currently being seriously considered for adoption. The lessons are investigated from the economic viewpoints.
"WHY NOT A VOLUNTEER ARMY?" REEXAMINING THE IMPACT OF MILITARY CONSCRIPTION ON ECONOMIC GROWTH FOR SINGAPORE
Authors: NG PAK SHUN
Published: March 2005

This paper evaluates the economic merits of a conscript or an all-volunteer military force for Singapore, focusing on military conscription as a subset of military expenditure. While many papers investigate the relationships between economic growth and conscription or defence spending, no concrete study has linked them to provide a new argument for or against conscription. This paper relates these three research areas to examine the economic costs and benefits of a conscript and an all-volunteer force for Singapore, taking into account the effects of military spending on the growth of the economy.
MULTIDIMENSIONAL GLOBAL MONOPOLE IN PRESENCE OF ELECTROMAGNETIC FIELD
Authors: RAHAMAN F. , GHOSH P. , KALAM M. , MANDAL S.
Published: March 2005

We study the gravitational properties of a global monopole in (D=d+2)-dimensional space–time in the presence of electromagnetic field.
STRUCTURE OF EXTENDED LOOP WAVE FUNCTION IN QUANTUM GRAVITY AND OPERATOR FORMALISM
Authors: SAITO MICHIYOSHI , NODA HUJIO , TASHIRO TSUTOMU
Published: March 2005

The structure of extended loop wave function is investigated in terms of the operator formalism. It is found that the extended loop wave function is characterized by the family number and classified by the partition of the family number. It is pointed out that the constraints to the extended loop function in quantum gravity exhibit a hierarchy structure.
THE EFFECT OF A LIGHT RADION ON THE TRIVIALITY BOUND ON HIGGS MASS
Authors: MAHANTA UMA , DAS PRASANTA KUMAR
Published: March 2005

In this paper we study how the triviality bound on Higgs mass in the context of the Standard Model is modified by a light stabilized radion of the Goldberger–Wise variety. Our approach is inherently perturbative. Including the radion contribution to β(λ) and β(gt) to one-loop we evolve the Higgs self coupling λ from the cutoff Λ(=<ϕ>) down to the electroweak scale μ0=v. The triviality bound is obtained by requiring that [Formula: see text] which is the perturbative limit. We also study the effect of small changes in the UVBC on the triviality bound both in the presence and absence of a light radion.
Gender dimorphism in rat liver mitochondrial oxidative metabolism and biogenesis
Authors: Justo Roberto , Boada Jordi , Frontera Margalida , Oliver Jordi , Bermúdez Jordi , Gianotti Magdalena
Published: March 2005

In the present study, we have investigated gender differences in rat liver mitochondrial oxidative metabolism. Total mitochondrial population (M) as well as the heavy (M1), medium (M3), and light (M8) mitochondrial fractions obtained by means of differential centrifugation steps at 1,000, 3,000, and 8,000 g, respectively, were isolated. Electron microscopic analysis was performed and mitochondrial protein content and cardiolipin levels, mitochondrial O2 flux, ATP synthase activity, mitochondrial membrane potential, and mitochondrial transcription factor A (TFAM) protein levels were measured in each sample. Our results indicate that mitochondria from females have higher protein content and higher cardiolipin levels, greater respiratory and phosphorylative capacities, and more-energized mitochondria in respiratory state 3. Moreover, protein levels of TFAM were four times greater in females than in males. Gender differences in the aforementioned parameters were more patent in the isolated heavy M1 and M3 mitochondrial fractions. The present study demonstrates that gender-related differences in liver mitochondrial function are due mainly to a higher capacity and efficiency of substrate oxidation, likely related to greater mitochondrial machinery in females than in males, which is in accord with greater mitochondrial differentiation in females.
Changes in intracellular Ca2+ and pH in response to thapsigargin in human glioblastoma cells and normal astrocytes
Authors: Kovacs Gergely Gy , Zsembery Akos , Anderson Susan J. , Komlosi Peter , Gillespie G. Yancey , Bell P. Darwin , Benos Dale J. , Fuller Catherine M.
Published: March 2005

Despite extensive work in the field of glioblastoma research no significant increase in survival rates for this devastating disease has been achieved. It is known that disturbance of intracellular Ca2+ ([Ca2+]i) and intracellular pH (pHi) regulation could be involved in tumor formation. The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a major regulator of [Ca2+]i. We have investigated the effect of inhibition of SERCA by thapsigargin (TG) on [Ca2+]i and pHi in human primary glioblastoma multiforme (GBM) cells and GBM cell lines, compared with normal human astrocytes, using the fluorescent indicators fura-2 and BCECF, respectively. Basal [Ca2+]i was higher in SK-MG-1 and U87 MG but not in human primary GBM cells compared with normal astrocytes. However, in tumor cells, TG evoked a much larger and faster [Ca2+]i increase than in normal astrocytes. This increase was prevented in nominally Ca2+-free buffer and by 2-APB, an inhibitor of store-operated Ca2+ channels. In addition, TG-activated Ca2+ influx, which was sensitive to 2-APB, was higher in all tumor cell lines and primary GBM cells compared with normal astrocytes. The pHi was also elevated in tumor cells compared with normal astrocytes. TG caused acidification of both normal and all GBM cells, but in the tumor cells, this acidification was followed by an amiloride- and 5-( N, N-hexamethylene)-amiloride-sensitive recovery, indicating involvement of a Na+/H+ exchanger. In summary, inhibition of SERCA function revealed a significant divergence in intracellular Ca2+ homeostasis and pH regulation in tumor cells compared with normal human astrocytes.
Direct block of cloned hKv1.5 channel by cytochalasins, actin-disrupting agents
Authors: Choi Bok Hee , Park Jung-Ah , Kim Kyung-Ryoul , Lee Ggot-Im , Lee Yong-Tae , Choe Huhn , Ko Seong-Hoon , Kim Min-Ho , Seo Yeon-Ho , Kwak Yong-Geun
Published: March 2005

The action of cytochalasins, actin-disrupting agents on human Kv1.5 channel (hKv1.5) stably expressed in Ltk− cells was investigated using the whole cell patch-clamp technique. Cytochalasin B inhibited hKv1.5 currents rapidly and reversibly at +60 mV in a concentration-dependent manner with an IC50 of 4.2 μM. Cytochalasin A, which has a structure very similar to cytochalasin B, inhibited hKv1.5 (IC50 of 1.4 μM at +60 mV). Pretreatment with other actin filament disruptors cytochalasin D and cytochalasin J, and an actin filament stabilizing agent phalloidin had no effect on the cytochalasin B-induced inhibition of hKv1.5 currents. Cytochalasin B accelerated the decay rate of inactivation for the hKv1.5 currents. Cytochalasin B-induced inhibition of the hKv1.5 channels was voltage dependent with a steep increase over the voltage range of the channel's opening. However, the inhibition exhibited voltage independence over the voltage range in which channels are fully activated. Cytochalasin B produced no significant effect on the steady-state activation or inactivation curves. The rate constants for association and dissociation of cytochalasin B were 3.7 μM/s and 7.5 s−1, respectively. Cytochalasin B produced a use-dependent inhibition of hKv1.5 current that was consistent with the slow recovery from inactivation in the presence of the drug. Cytochalasin B (10 μM) also inhibited an ultrarapid delayed rectifier K+ current ( IK,ur) in human atrial myocytes. These results indicate that cytochalasin B primarily blocks activated hKv1.5 channels and endogenous IK,ur in a cytoskeleton-independent manner as an open-channel blocker.
Developmental expression and biophysical characterization of a Drosophila melanogaster aquaporin
Authors: Kaufmann Nancy , Mathai John C. , Hill Warren G. , Dow Julian A. T. , Zeidel Mark L. , Brodsky Jeffrey L.
Published: March 2005

Aquaporins (AQPs) accelerate the movement of water and other solutes across biological membranes, yet the molecular mechanisms of each AQP's transport function and the diverse physiological roles played by AQP family members are still being defined. We therefore have characterized an AQP in a model organism, Drosophila melanogaster, which is amenable to genetic manipulation and developmental analysis. To study the mechanism of Drosophila Malpighian tubule (MT)-facilitated water transport, we identified seven putative AQPs in the Drosophila genome and found that one of these, previously named DRIP, has the greatest sequence similarity to those vertebrate AQPs that exhibit the highest rates of water transport. In situ mRNA analyses showed that DRIP is expressed in both embryonic and adult MTs, as well as in other tissues in which fluid transport is essential. In addition, the pattern of DRIP expression was dynamic. To define DRIP-mediated water transport, the protein was expressed in Xenopus oocytes and in yeast secretory vesicles, and we found that significantly elevated rates of water transport correlated with DRIP expression. Moreover, the activation energy required for water transport in DRIP-expressing secretory vesicles was 4.9 kcal/mol. This low value is characteristic of AQP-mediated water transport, whereas the value in control vesicles was 16.4 kcal/mol. In contrast, glycerol, urea, ammonia, and proton transport were unaffected by DRIP expression, suggesting that DRIP is a highly selective water-specific channel. This result is consistent with the homology between DRIP and mammalian water-specific AQPs. Together, these data establish Drosophila as a new model system with which to investigate AQP function.
Dissection of Bidirectional Synaptic Plasticity Into Saturable Unidirectional Processes
Authors: O'Connor Daniel H. , Wittenberg Gayle M. , Wang Samuel S.-H.
Published: March 2005

In populations of synapses, overall synaptic strength can undergo either a net strengthening (long-term potentiation) or weakening (long-term depression). These phenomena have distinct induction pathways, but the functional outcome is usually measured as a single lumped quantity. In hippocampal CA3-CA1 synapses, we took two approaches to study the activity dependence of each phenomenon in isolation. First, we selectively blocked one process by applying kinase or phosphatase inhibitors known, respectively, to block potentiation or depression. Second, we saturated depression or potentiation and examined the activity dependence of the converse process. The resulting unidirectional learning rules could be recombined to give a well-known bidirectional frequency-dependent learning rule under the assumption that when both pathways are activated kinases dominate, resulting in potentiation. Saturation experiments revealed an additional process in which potentiated synapses can be locked at high strength. Saturability of the components of plasticity implies that the amount of plasticity contributed by each pathway depends on the initial level of strength of the synapses. Variation in the distribution of initial synaptic strengths predicts a form of metaplasticity and can account for differences in learning rules observed under several physiological and genetic manipulations.