bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical investigation and experimental validation of the performance of a tubular packed bed reactor for hydrogenation of diene‐based polymers
Authors: Madhuranthakam Chandra Mouli R. , Pan Qinmin , Rempel Garry L. 
Published: May 2009

AbstractA process which comprised a tubular reactor (that can be packed with different internal structures) has been modeled and theoretically analyzed for conducting the hydrogenation of nitrile butadiene rubber (NBR). The dynamics of the tubular reactor and the intrinsic hydrogenation kinetics are coupled, and detailed numerical simulations are performed under isothermal and isobaric conditions. The proposed model thus obtained involves coupled, nonlinear, partial differential equations (distributed parameter system). The effect of different reactor design parameters such as Peclet number, carbon–carbon double bond loading, mass transfer to reaction resistance, and solubility of hydrogen with respect to hydrogenation of the NBR has been investigated numerically. The conversions predicted using the proposed model for tubular packed bed reactor are compared with those possible in conventional plug flow reactor and continuous stirred tank reactor models. The optimal parameters and operating conditions for efficient production of hydrogenated NBR are suggested. Finally, the validity of the proposed model is confirmed by comparing the predicted and the experimental degree of hydrogenation obtained in a tubular reactor packed with Intalox saddles. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Estimation of the interaction energy between small molecules and a silica model as an approach for predicting the interaction order between elastomers and silica
Authors: Pérez León D , Florez Elizabeth , Mark James E , López Betty L 
Published: May 2009

AbstractBACKGROUND: Many elastomers are reinforced with fillers to improve their mechanical properties; good reinforcement requires favorable interactions between the elastomeric chains and the surfaces of the filler particles. A useful goal is the development of computational methods that estimate these interactions, and thereby guide choices of fillers for elastomers based on the structures of the two components in nanocomposites in general.RESULTS: Experimental results available from inverse gas chromatography rank nitriles, aromatics and 1‐alkenes with regard to the magnitude of favorable interactions with silica reinforcing particles. Calculations using the Gaussian 03 package of computer programs were carried out, both with and without corrections for superposition errors. For the nitrile compounds, the formation of hydrogen bonds was predicted, and the interactions of the aromatic and 1‐alkene compounds with silica were shown to be dependent on electron transfer from the silica to the tested molecules.CONCLUSION: The method developed should be useful for ranking polymer–filler combinations in general with regard to the interactions known to be conducive to good reinforcement. Copyright © 2009 Society of Chemical Industry
Improved prediction of protein side‐chain conformations with SCWRL4
Authors: Krivov Georgii G. , Shapovalov Maxim V. , Dunbrack Roland L. 
Published: May 2009

AbstractDetermination of side‐chain conformations is an important step in protein structure prediction and protein design. Many such methods have been presented, although only a small number are in widespread use. SCWRL is one such method, and the SCWRL3 program (2003) has remained popular because of its speed, accuracy, and ease‐of‐use for the purpose of homology modeling. However, higher accuracy at comparable speed is desirable. This has been achieved in a new program SCWRL4 through: (1) a new backbone‐dependent rotamer library based on kernel density estimates; (2) averaging over samples of conformations about the positions in the rotamer library; (3) a fast anisotropic hydrogen bonding function; (4) a short‐range, soft van der Waals atom–atom interaction potential; (5) fast collision detection using k‐discrete oriented polytopes; (6) a tree decomposition algorithm to solve the combinatorial problem; and (7) optimization of all parameters by determining the interaction graph within the crystal environment using symmetry operators of the crystallographic space group. Accuracies as a function of electron density of the side chains demonstrate that side chains with higher electron density are easier to predict than those with low‐electron density and presumed conformational disorder. For a testing set of 379 proteins, 86% of χ1 angles and 75% of χ1+2 angles are predicted correctly within 40° of the X‐ray positions. Among side chains with higher electron density (25–100th percentile), these numbers rise to 89 and 80%. The new program maintains its simple command‐line interface, designed for homology modeling, and is now available as a dynamic‐linked library for incorporation into other software programs. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Modulation of presynaptic glucocorticoid receptors on glutamate release from rat hippocampal nerve terminals
Authors: Wang Chia‐Chuan , Wang Su‐Jane 
Published: May 2009

AbstractIn this study, we have examined the role of corticosterone (CORT) in the regulation of neuronal glutamate release using nerve terminals (synaptosomes) isolated from the rat hippocampus. Adult male Sprague‐Dawley rats received either a chronic systemic administration of CORT (daily 25 mg/kg in sesame oil, subcutaneously) or long‐term bilateral adrenalectomy (ADX) (3–4 weeks), and then the release of 4‐aminopyridine (4AP)‐evoked endogenous glutamate and the levels of glucocorticoid receptor (GR) expression from hippocampal nerve terminals were studied. Chronic administration of CORT resulted in a significant increase of 4AP‐evoked glutamate release from hippocampal nerve terminals, whereas ADX reduced 4AP‐evoked glutamate release. In addition, chronic administration of CORT and ADX induced a significant reduction and increase in GR expression in hippocampal synaptosomes, respectively, as detected by Western blots. Furthermore, acute treatment of CORT or dexamethasone facilitated 4AP‐evoked glutamate release from synaptosomes freshly isolated from naïve rat hippocampus and this effect can be significantly prevented by pretreatment of GR antagonist mifepristone, but not by mineralocorticoid receptor (MR) antagonist RU28318. Together, our results strongly support the presence of GRs on presynaptic nerve terminals in the rat hippocampus acting to facilitate the release of neuronal glutamate. Synapse 63:745–751, 2009. © 2009 Wiley‐Liss, Inc.
Characterization of Oil Extracted from Buriti Fruit (Mauritia flexuosa) Grown in the Brazilian Amazon Region
Authors: Silva Simone M. , Sampaio Klicia A. , Taham Thiago , Rocco Silvana A. , Ceriani Roberta , Meirelles Antonio J. A. 
Published: May 2009

AbstractFive samples of buriti oil from industrial and artisanal suppliers were characterized in terms of nutritional quality parameters (nutraceutical levels) and acidity. As a first screening, each sample was analyzed by titration, spectrophotometry and an HPLC method, and the results were compared. As expected, artisanal samples showed lower acidity and higher levels of carotenes and tocols (tocopherols and tocotrienols). A blend of industrial and artisanal samples in suitable proportions was completely characterized in terms of analytical and physico‐chemical properties, i.e., fatty acid composition, iodine value, partial and total acylglycerol contents, refractive index (40 °C), saponification value, unsaponifiable matter, acidity (expressed as % of oleic acid), peroxide value, phosphorus content, oil stability index, tocol and carotene concentrations. The results of the present study showed that buriti oil is a valuable source of monounsaturated fatty acids, and vitamins A and E. No previous work in the literature has analyzed buriti oil to this extent. The chromatographic method using HPLC was effective in qualifying and quantifying tocopherols, tocotrienols and carotenes.
Evoked potentials generated by noxious stimulation in the human infant brain
Authors: Slater Rebeccah , Worley Alan , Fabrizi Lorenzo , Roberts Siân , Meek Judith , Boyd Stewart , Fitzgerald Maria 
Published: May 2009

AbstractWhile human infants can display distinctive behavioural and physiological spinal cord and brainstem responses to noxious stimulation, it is not known whether cortical neurons are specifically activated by noxious stimuli in newborns. Here, using a novel approach to time‐lock an EEG recording to a clinically required heel lance, we show the presence of a distinct nociceptive‐specific potential in newborn infants (35–39 weeks postmenstrual age). The potential can be observed in single trials in the central electrodes (Cz and CPz) and using principal component analysis is characterised by a positivity that occurs at approximately 560 ms post‐stimulus (N420–P560; P, positive; N, negative). The magnitude of the nociceptive‐specific potential is not dependent on sleep state, whereas an earlier potential (N150–P260–N430), which is sleep‐state dependent, is evoked by both noxious and non‐noxious stimulation. These results provide the first direct evidence of specific noxious‐evoked neural activity in the infant brain and suggest that newborn infants are capable of the sensory‐discriminative aspects of pain experience.
Gamma-ray bursts as a threat to life on Earth
Authors: Thomas B.C. 
Published: May 2009

AbstractGamma-ray bursts (GRBs) are likely to have made a number of significant impacts on the Earth during the last billion years. The gamma radiation from a burst within a few kiloparsecs would quickly deplete much of the Earth's protective ozone layer, allowing an increase in solar ultraviolet radiation reaching the surface. This radiation is harmful to life, damaging DNA and causing sunburn. In addition, NO2 produced in the atmosphere would cause a decrease in visible sunlight reaching the surface and could cause global cooling. Nitric acid rain could stress portions of the biosphere, but the increased nitrate deposition could be helpful to land plants. We have used a two-dimensional atmospheric model to investigate the effects on the Earth's atmosphere of GRBs delivering a range of fluences, at various latitudes, at the equinoxes and solstices, and at different times of day. We have estimated DNA damage levels caused by increased solar UVB radiation, reduction in solar visible light due to NO2 opacity, and deposition of nitrates through rainout of HNO3. In this paper we give a concise review of this work and discuss current and future work on extending and improving our estimates of the terrestrial impact of a GRB.
The Impact of Climate Change on Agriculture in Developing Countries
Authors: Mendelsohn Robert 
Published: May 2009

AbstractThe largest known economic impact of climate change is upon agriculture because of the size and sensitivity of the sector. Warming causes the greatest harm to agriculture in developing countries primarily because many farms in the low latitudes already endure climates that are too hot. This paper reviews several studies that measure the size of the impact of warming on farms in developing countries. Even though adaptation will blunt some of the worst predicted outcomes, warming is expected to cause large damages to agriculture in developing countries over the next century.
Rent-Maximization Versus Competition in the Western and Central Pacific Tuna Fishery
Authors: Hannesson Rögnvaldur , Kennedy John 
Published: May 2009

AbstractThe potential for achieving sustainable and efficient harvesting of three species of migratory tuna in the Western and Central Pacific Ocean is examined. The stocks reside in exclusive economic zones (mainly those of Pacific island countries) and in the high seas. Most harvesting is carried out by distant water fishing nations, including the USA, Japan, Taiwan, China, and Korea. Problems of achieving sustainability and efficiency in the harvesting of the stocks by disparate countries are made more difficult due to changes in the harvesting levels of one fleet affecting the rents of another fleet through changes in the age distribution of stock. These types of problem are under review by the Western and Central Pacific Fisheries Commission. Results from an age-structured steady-state bioeconomic model are used to show: the changes in fleet rents and catches of tuna if all fleets form a cooperative grand coalition to deploy fishing effort to maximize rents over the region; the likely non-stability of the grand coalition; and the inferior Nash Equilibria outcomes if fleets fish non-cooperatively to maximize their own rents.
Quantifying the Airshed for Fine Particles: Using Geographic Information System (GIS), Remote Sensing Data, andIn SituMonitoring
Authors: Rush Alan C. 
Published: May 2009

AbstractThe advances in remote sensing and the need for air pollution data in remote areas highlighted the need to examine the current capabilities to fill gaps in ambient air monitoring. This paper describes delineating the boundaries of fine particulate matter (PM2.5) nonattainment areas by integrating PM ambient data and satellite aerosol optical depth (AOD) with geostatistical kriging. Correlation between the ground and satellites for the three year average was adequate in the upper Midwest and northeast (greater than r = .57) and typically very poor in the rest of the country (less than r = .20). To improve the geospatial prediction of the extent of aerosols, satellite AOD data from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensor was used. This addition of daily air quality data aids prediction of air pollution extent, making the approximation of fine particle airsheds possible.
Payment for Environmental Services: Estimating Demand Within a Tropical Watershed
Authors: Ortega-Pacheco Daniel V. , Lupi Frank , Kaplowitz Michael D. 
Published: May 2009

Abstract
The long-term success of payment for environmental services (PES) schemes depends on adequate demand for services and sustainable financing. We examine the viability of using locally financed payments to protect watershed services in rural eastern Costa Rica. Using dichotomous choice contingent valuation, we measure households' willingness to pay higher water bills for a local PES programme to adjust upstream land use practices to protect downstream water quality. We found that every income segment of the local population of water-users exhibited significant demand and willingness to finance the PES programme to protect local water quality.
Isolation and characterization of multipotent stem cells from human cruciate ligaments
Authors: Cheng M‐T. , Yang H‐W. , Chen T‐H. , Lee O. K‐S. 
Published: May 2009

AbstractObjectives:  Mesenchymal stem cells have great potential for tissue regeneration, and these cells can be harvested from a variety of tissues; however, up to now it has not been clear whether stem cells could be isolated from cruciate ligaments of the knee joint. The aim of our study was to isolate and characterize stem cells from both anterior and posterior cruciate ligaments (ACL and PCL) of humans.Materials and methods:  Cruciate igaments were obtained from patients receiving total knee arthroplasty for advanced osteoarthritis and plastic‐adherent cells were serially passaged. In vitro chondrogenic, osteogenic and adipogenic abilities of the cells were evaluated by reverse transcriptase–polymerase chain reaction and histological study. Karyotyping and surface immunophenotyping of the cells were performed.Results:  It was found that a population of ligament‐derived cells could be expanded and subcultured extensively. These cells were able to differentiate into osteoblasts, chondrocytes and adipocytes under appropriate inductions. Their phenotypic characteristics were similar to those of bone marrow mesenchymal stem cells. Karyotyping was normal after serial passage.Conclusions:  In summary, our study demonstrates that human multipotent stem cells can be isolated and expanded from human ACL and PCL, which are easily obtained from patients following total knee or cruciate ligament reconstructive surgery. Self‐renewal and mesodermal differentiation potential of these cells make them a viable alternative source for use in regenerative medicine.
Screening of autosomal gene deletions in patients with hypogonadotropic hypogonadism using multiplex ligation‐dependent probe amplification: detection of a hemizygosis for the fibroblast growth factor receptor 1
Authors: Trarbach Ericka Barbosa , Teles Milena Gurgel , Costa Elaine Maria Frade , Abreu Ana Paula , Garmes Heraldo Mendes , Guerra Gil , Baptista Maria Tereza Matias , De Castro Margaret , Mendonca Berenice Bilharinho , Latronico Ana Claudia 
Published: May 2009

SummaryObjective  Congenital hypogonadotropic hypogonadism with anosmia (Kallmann syndrome) or with normal sense of smell is a heterogeneous genetic disorder caused by defects in the synthesis, secretion and action of gonadotrophin‐releasing hormone (GnRH). Mutations involving autosomal genes have been identified in approximately 30% of all cases of hypogonadotropic hypogonadism. However, most studies that screened patients with hypogonadotropic hypogonadism for gene mutations did not include gene dosage methodologies. Therefore, it remains to be determined whether patients without detected point mutation carried a heterozygous deletion of one or more exons.Measurements  We used the multiplex ligation‐dependent probe amplification (MLPA) assay to evaluate the potential contribution of heterozygous deletions of FGFR1, GnRH1, GnRHR, GPR54 and NELF genes in the aetiology of GnRH deficiency.Patients  We studied a mutation‐negative cohort of 135 patients, 80 with Kallmann syndrome and 55 with normosmic hypogonadotropic hypogonadism.Results  One large heterozygous deletion involving all FGFR1 exons was identified in a female patient with sporadic normosmic hypogonadotropic hypogonadism and mild dimorphisms as ogival palate and cavus foot. FGFR1 hemizygosity was confirmed by gene dosage with comparative multiplex and real‐time PCRs.Conclusions  FGFR1 or other autosomal gene deletion is a possible but very rare event and does not account for a significant number of sporadic or inherited cases of isolated GnRH deficiency.
Seed banks cause elevated generation times and effective population sizes of Arabidopsis thaliana in northern Europe
Authors: LUNDEMO SVERRE , FALAHATI‐ANBARAN MOHSEN , STENØIEN HANS K. 
Published: May 2009

AbstractIt is commonly found that effective population sizes of natural populations are much smaller than census sizes of plants and animals. However, theoretical studies have shown that factors rarely investigated empirically, like seed banks in plants and diapause in animals, may have profound influence on effective sizes. Here we investigate whether the presence of seed banks can explain the relatively high genetic variability observed in northern European Arabidopsis thaliana populations with small census sizes. We have genotyped three above‐ and below‐ ground cohorts in 27 Norwegian populations using single nucleotide polymorphism markers. Although the populations varied extensively in levels of variability within and between cohorts, standard genetic population measures were comparable to those obtained in previous studies on above‐ground cohorts using microsatellite markers. Estimated effective population sizes are larger for total populations (containing both seed bank and above‐ground cohorts for 1 year) compared to each of the cohorts considered separately. Using a conservative approach, we find that the effective sizes are larger than census sizes of local populations, and that the effective generation time is higher than 1 year (3–4 years, on average), making A. thaliana a perennial semelparous plant at many northern European localities.
Longevity of inoculum production by Diplodia pinea on red pine cones
Authors: Munck I. A. , Stanosz G. R. 
Published: May 2009

SummaryIn summer of 2004, pycnidia of Diplodia pinea were observed on cones of Pinus resinosa that had matured and opened during previous years, but had been retained in canopies of trees at a mature red pine plantation in southern Wisconsin. Surveys during the winter and early summer of three consecutive years (2005–2007) to determine incidence and abundance of D. pinea conidia on cones of different ages in this stand. Cones from each age class consistently bore pycnidia with conidia of D. pinea. Although cones collected in June of the year after their maturation tended to yield more D. pinea conidia than older cones, large numbers of conidia were obtained from cones even 3 years after maturation. Perennial availability of inoculum due to persistence of D. pinea on cones of several ages in the overstory or in adjacent stands should be considered when regenerating red pine in areas where this pathogen is known to be present.
Translating nociceptor sensitivity: the role of axonal protein synthesis in nociceptor physiology
Authors: Price Theodore J. , Géranton Sandrine M. 
Published: May 2009

AbstractThe increased sensitivity of peripheral pain‐sensing neurons, or nociceptors, is a major cause of the sensation of pain that follows injury. This plasticity is thought to contribute to the maintenance of chronic pain states. Although we have a broad knowledge of the factors that stimulate changes in nociceptor sensitivity, the cellular mechanisms that underlie this plasticity are still poorly understood; however, they are likely to involve changes in gene expression required for the phenotypic and functional changes seen in nociceptive neurons after injury. While the regulation of gene expression at the transcriptional level has been studied extensively, the regulation of protein synthesis, which is also a tightly controlled process, has only recently received more attention. Despite the established role of protein synthesis in the plasticity of neuronal cell bodies and dendrites, little attention has been paid to the role of translation control in mature undamaged axons. In this regard, several recent studies have demonstrated that the control of protein synthesis within the axonal compartment is crucial for the normal function and regulation of sensitivity of nociceptors. Pathways and proteins regulating this process, such as the mammalian target of rapamycin signaling cascade and the fragile X mental retardation protein, have recently been identified. We review here recent evidence for the regulation of protein synthesis within a nociceptor’s axonal compartment and its contribution to this neuron’s plasticity. We believe that an increased understanding of this process will lead to the identification of novel targets for the treatment of chronic pain.