bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pollen/climate calibration based on a near‐annual peat sequence from the Swiss Alps
Authors: Kamenik Christian , Van der Knaap Willem O. , Van Leeuwen Jacqueline F. N. , Goslar Tomasz 
Published: May 2009

AbstractThe objective of this study was to develop a high‐resolution pollen‐based climate inference model (using ‘calibration in time’) for the mire Mauntschas (SE Swiss Alps, 1818 m above sea level). We focused on 11 types of pollen and spores (referred to as pollen for simplicity) for which we produced 150 year (a) time series of accumulation rates and percentages. Dating of these series was based on 29 14C dates from pure Sphagnum, spheroidal carbonaceous particles, larch bud moth events, and an age–depth model that took into account probabilities of calibrated 14C ages, the degree of curvature of the age–depth line and changes in concentrations of all major pollen types. Time resolution was 1–5 a. We first smoothed the series using a 3 a triangular filter, thus removing time‐resolution dependent changes in variability, and minimising effects of potential dating uncertainties. Using redundancy analysis, we then studied the simultaneous response of the selected pollen to 288 different combinations of monthly temperature or precipitation data measured at Sils Maria (1798 m above sea level), located 9 km from Mauntschas. From AD 1954 to 2002, mean May–August air temperature from the same year explained most (18.1%) of the variation in pollen accumulation rates. The amount of explained variation dropped to 9.9% after detrending all data with a 50 a high‐pass filter, which possibly removed non‐climatic trends. Temperature explained more variation among PAR than among pollen percentages; however, during the verification period (AD 1864–1953) the former were potentially affected by dating uncertainties and could not be used. For developing a pollen‐based temperature inference model, we tested ordinary least squares regression, time series regression, ridge regression, principal components regression, and partial least squares regression. During the well‐dated calibration period (AD 1954–2002), ordinary least squares regression based on percentages of six pollen types turned out to be the most parsimonious model, having a cross‐validated root mean square error of prediction of 0.23°C for mean April–November temperature. A comparison of reconstructed with measured temperature from Sils Maria during the verification period showed that the model best reflected long‐term (at least decadal‐scale) temperature changes. Copyright © 2009 John Wiley & Sons, Ltd.
Heterogeneous electrochemical characteristics of biofilm/metal interface and local electrochemical techniques used for this purpose
Authors: Wang W. , Zhang X. , Wang J. 
Published: May 2009

AbstractBiofilms on metal surface in an aqueous environment is a complex electrochemical system. The heterogeneous electrochemical characteristics of biofilm/metal interface and local electrochemical techniques used for this purpose are discussed in this work. The techniques presented in this work include microelectrode, scanning vibrating electrode, the wire beam electrode method, and scanning electrochemical microscopy. Two potentially useful techniques, localized electrochemical impedance spectroscopy and scanning Kelvin probe force microscopy, are also discussed. The advantages and limitations of these techniques are summarized. A new approach: numerical simulation of micro‐electrochemical heterogeneity of biofilm covered metals is introduced.
Corrosion and electrochemical behaviors of pure aluminum in novel KOH‐ionic liquid‐water solutions
Authors: Wang J. M. , Wang J. B. , Shao H. B. , Zeng X. X. , Zhang J. Q. , Cao C. N. 
Published: May 2009

AbstractThe corrosion and electrochemical behaviors of pure aluminum in KOH‐ionic liquid‐water solutions with variable volume ratios of water and the ionic liquid 1‐butyl‐3‐methyl imidazolium tetrafluoroborate (BMIMBF4) were for the first time investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, and electrochemical impedance spectroscopy (EIS). The results of hydrogen collection experiments showed that aluminum has a low corrosion rate in KOH‐BMIMBF4‐H2O solutions, and the corrosion rate decreases with increase in BMIMBF4 content in the electrolytes. The results of electrochemical experiments revealed that aluminum is electrochemically active over a very wide potential window in the KOH‐BMIMBF4‐H2O solutions, and its electrochemically kinetic mechanism is similar to that in the corresponding aqueous solution; the increase in KOH and water contents in the electrolytes may improve the anodic dissolution performance of aluminum. It was found that aluminum presents excellent galvanostatic discharge performance in the 2.0 M KOH BMIMBF4‐H2O mixed solution with 60% water.
Acardiac fetus complicating a triplet pregnancy: management and outcome
Authors: Sepulveda Waldo , Wong Amy E. , Bustos Juan C. , Flores Ximena , Alcalde Juan L. 
Published: May 2009

AbstractObjectiveTo report our experience with the management of triplet pregnancies complicated by an acardiac fetus.MethodsDuring the 5‐year period from 2003 to 2008, five cases were identified. The prenatal sonographic findings, antepartum course, antenatal intervention if performed, and perinatal outcome of each case were reviewed.ResultsFour pregnancies were spontaneously conceived and one was achieved by in vitro fertilization. Three pregnancies were dichorionic and two were monochorionic, and two acardiac fetuses were part of a monoamniotic set. All cases underwent an early sonographic examination, but the diagnosis was only made in the first trimester in only two cases, as the acardiac fetus was overlooked or inaccurately identified as a dead fetus in the remaining three cases. Early fetal demise before 12 weeks occurred in a case of monochorionic‐triamniotic triplets. Percutaneous laser coagulation of the main intra‐abdominal vessel was attempted at 17 weeks in two cases, with subsequent delivery after 34 weeks and perinatal survival of three of the four structurally normal fetuses. In the other two pregnancies which were managed expectantly, both were complicated by severe preterm delivery with perinatal survival of three of the four structurally normal fetuses. Overall, there were no survivors in one case, one twin survived in two cases, and two twins survived in the remaining two cases. None of the survivor had neurological sequelae.ConclusionsThe presence of an acardiac fetus in a triplet pregnancy carries a high risk for poor pregnancy outcome, including fetal death and severe preterm labor. Prenatal intervention may be indicated in some cases, but does not prevent fetal death of the pump twin. Copyright © 2009 John Wiley & Sons, Ltd.
Quantification of the distribution of carbon black in natural rubber/polybutadiene blends by differential scanning calorimetry
Authors: Portal Julien , Carrot Christian , Majeste Jean‐Charles , Cocard Stéphane , Pelissier Vincent , Anselme‐Bertrand Isabelle 
Published: May 2009

AbstractThe distribution of carbon black (CB) in uncured blends of natural rubber (NR) and polybutadiene (PB) can be quantified using DSC. The crystallization temperature of PB containing CB, measured during cooling from the melt, increases with the CB loading. This phenomenon was used to calculate the CB content in PB and conversely in NR in NR/PB/CB mixtures. Two different blends containing N550 CB were studied. A deeper analysis was performed over the entire composition range of NR/PB blends filled with N234 CB. Two different trends were highlighted depending on composition. Below 50 wt% of NR in the elastomer phase, the crystallization temperature of PB is higher than that of pure PB indicating that a part of the CB is dispersed in PB. Above 50 wt% of NR, the crystallization temperature of PB is lower than that of pure PB, indicating that the whole CB is in the NR phase and that fractionated crystallization of PB simultaneously occurs. Both phenomena are consistent as the dispersed phase morphology is favored by a large increase of the matrix viscosity by the filler. For both CBs, the results indicate that CB has larger affinity for NR than for PB. This tendency was confirmed by transmission electron microscopy. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
New tetrafunctional monomer 1,3‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzene in the synthesis of porous microspheres
Authors: Grochowicz Marta , Gawdzik Barbara , Bartnicki Andrzej 
Published: May 2009

AbstractSynthesis and properties of the new aromatic tetrafunctional methacrylate monomer 1,3‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzene are presented. This monomer was applied for the synthesis of porous microspheres. It was copolymerized with trimethylolpropane trimethacrylate in the presence of pore‐forming diluents, decan‐1‐ol and chlorobenzene. Influence of diluents composition on their porous structures was studied. Thermal resistance and tendency to swell in different organic diluents for a chosen sample were also determined. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3190–3201, 2009
Grafting of montmorillonite nano‐clay with butyl acrylate and methyl methacrylate by atom transfer radical polymerization: Blends with poly(BuA‐co‐MMA)
Authors: Karesoja Mikko , Jokinen Harri , Karjalainen Erno , Pulkkinen Petri , Torkkeli Mika , Soininen Antti , Ruokolainen Janne , Tenhu Heikki 
Published: May 2009

Abstract11‐(2‐Bromo‐2‐methyl)propionyl‐oxy‐undecyl trichlorosilane atom transfer radical polymerization (ATRP) initiator was covalently attached on montmorillonite clay platelets via silylation reactions. The initiator clay was used to polymerize butyl acrylate (BuA) and methyl methacrylate (MMA) on the clay surface. Polymerization was performed in bulk monomer solution or in DMSO. Polymer modified clay was mixed with a poly(BuA‐co‐MMA) matrix. Small angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) showed that clay modified in DMSO gave exfoliated composites when mixed with the matrix copolymer. Mechanical properties of the composites were studied by dynamic mechanical thermal analysis (DMTA). The results showed that the mechanical properties were improved as a function of clay content, as well with an increasing homogeneity of the nanocomposite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3086–3097, 2009
A photo‐oxidizable kinetic pathway of three‐component photoinitiator systems containing porphrin dye (Zn‐tpp), an electron donor and diphenyl iodonium salt
Authors: Kim Dongkwan , Stansbury Jeffrey W. 
Published: May 2009

AbstractA series of kinetic experiments were conducted involving visible‐light activated free radical polymerizations with three‐component photoinitiators and 2‐hydroxyethyl methacrylate (HEMA). Three‐component photoinitiator systems generally include a light‐absorbing photosensitizer (PS), an electron donor and an electron acceptor. To compare kinetic efficiency, we used thermodynamic feasibility and measured kinetic data. For this study, 5,10,15,20‐tetraphenyl‐21H,23H‐porphyrin zinc (Zn‐tpp) and camphorquinone (CQ) were used as the PSs. The Rehm‐Weller equation was used to verify the thermodynamic feasibility for the photo‐induced electron transfer reaction. Using the thermodynamic feasibility, we suggest two different kinetic mechanisms, which are (i) photo‐reducible series mechanism of CQ and (ii) photo‐oxidizable series mechanism of Zn‐tpp. Kinetic data were measured by near‐IR spectroscopy and photo‐differential scanning calorimetry based on an equivalent concentration of excited state PS. We report that the photo‐oxidizable series mechanism using Zn‐tpp produced dramatically enhanced conversions and rates of polymerizations compared with those associated with the photo‐reducible series mechanism using CQ. It was concluded from the kinetic results that the photo‐oxidizable series mechanism efficiently retards back electron transfer and the recombination reaction step. In addition, the photo‐oxidizable series mechanism provides an efficient secondary reaction step that involves consumption of the dye‐based radical and regeneration of the original PS. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3131–3141, 2009
Substituent effects in ethene/styrene copolymerization: Dormant state destabilization?
Authors: Theaker Giles W. , Morton Colin , Scott Peter 
Published: May 2009

AbstractHomogeneous metallocene and CGC catalyzed copolymerizations of ethene (E) and various substituted styrenes are examined. It is found that those with p‐tert‐butylstyrene (TBS) occur with dramatically higher degrees of incorporation and overall productivity than those observed under the same conditions with styrene. It is argued that that the σ‐donating effect of the tert‐butyl substituent is responsible for this performance, effecting a destabilization of an otherwise dormant benzylic species following 2,1‐insertion of the styrene. It was found possible to produce what is essentially TBS‐alt‐E (44% TBS with no sequential TBS units) using a standard constrained geometry catalyst at impressively high productivity [1.5 × 106 g/(molTi.barE.h)] and unusually low concentration of TBS (0.7 M). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3111–3117, 2009
Feeding cessation effects of chlorantraniliprole, a new anthranilic diamide insecticide, in comparison with several insecticides in distinct chemical classes and mode‐of‐action groups
Authors: Hannig Greg T , Ziegler Melissa , Marçon Paula G 
Published: May 2009

AbstractBACKGROUND: Chlorantraniliprole is a novel anthranilic diamide insecticide, efficacious for control of lepidopteran insect pests, as well as some species in the orders Coleoptera, Diptera and Hemiptera. In this study, the speed of action of chlorantraniliprole was compared with that of seven commercial insecticides by means of ingestion bioassays against larvae of Plutella xylostella L., Trichoplusia ni (Hübner), Spodoptera exigua (Hübner) and Helicoverpa zea (Boddie).RESULTS: Based on feeding cessation and reduction in feeding damage, chlorantraniliprole is among the fastest‐acting insecticides available for control of lepidopteran pests, comparable in speed of action with methomyl, lambda‐cyhalothrin and esfenvalerate, and faster than emamectin benzoate, indoxacarb, methoxyfenozide and metaflumizone.CONCLUSION: The speed of action of chlorantraniliprole against target pest species, based on time for feeding cessation and reduction in feeding damage, is significantly greater than that of most recently developed insecticides and comparable only with the speed of action of the fast‐acting carbamates and pyrethroids. In addition, chlorantraniliprole has a favorable toxicological and ecotoxicological profile. It belongs to a new chemical class with a novel mode of action and is effective against insect populations that have developed resistance to other insecticide groups, thus representing an attractive new tool for integrated pest management programs. Copyright © 2009 Society of Chemical Industry
Effects of exposure to oxamyl, carbofuran, dichlorvos, and lindane on acetylcholinesterase activity in the gills of the Pacific oyster Crassostrea gigas
Authors: Anguiano Gerardo A. , Amador Alejandro , Moreno‐Legorreta Manuel , Arcos‐Ortega Fabiola , Vazquez‐Boucard Celia 
Published: May 2009

AbstractAcetylcholinesterase (AChE) activity has been used to test the exposure of mollusk bivalves to pesticides and other pollutants. The Pacific oyster Crassostrea gigas is a species with a worldwide distribution, and it has a high commercial value. The use of this species as a bioindicator in the marine environment, and the use of measurements of AChE activity in tissues of C. gigas require prior evaluation of organisms exposed to several toxic compounds in the laboratory. In our study, the effects of pesticides on AChE activity in the gills and mantle tissues of C. gigas were analyzed by exposing animals to organophosphate (dichlorvos), carbamate (carbofuran and oxamyl), and organochlorine (lindane) pesticides. Adult Pacific oysters were exposed to several concentrations (0.1–200 μM) of dichlorvos, carbofuran, and oxamyl for 96 h, and lindane (1.0 and 2.5 μM) was applied for 12 days. In gill tissues, all pesticides analyzed caused a decrease in AChE activity when compared to the control unexposed group. The mean inhibition concentration (IC50) values were determined for dichlorvos, carbofuran, and oxamyl pesticides. Dichlorvos had the highest toxic effect, with an IC50 of 1.08 μM; lesser effects were caused by oxamyl and carbofuran, with IC50s of 1.67 and 3.03 μM, respectively. This study reports the effects of pesticides with several chemical structures and validates measurement of AChE activity in the gill tissues of C. gigas for use in environmental evaluations or food quality tests. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 327–332, 2010.
Effects of exogenous GSH and methionine on methylation of inorganic arsenic in mice exposed to arsenite through drinking water
Authors: Jin Yaping , Zhao Fenghong , Zhong Yuan , Yu Xiaoyun , Sun Di , Liao Yingjun , Lv Xiuqiang , Li Gexin , Sun Guifan 
Published: May 2009

AbstractWe hypothesized that chronic exposure to arsenic would deplete the reduced glutathione (GSH) and methionine in vivo, thereby impair the methylation capacity of inorganic arsenic (iAs) ingested. Our experiment was designed to explore the effects of exogenous GSH and methionine on arsenic methylation in mice exposed to arsenite via drinking water. Levels of iAs, monomethylarsenic acid (MMAs), and dimethylarsenic acid (DMAs) in the liver and blood were determined by the method of hydride generation coupled with atomic absorption spectrophotometry. Compared with mice exposed to arsenite alone, administration of GSH or methionine increased the secondary methylation index in the liver and primary methylation index in the blood, which resulted in the consequent increase of DMAs percent and decrease of iAs percent in the blood. Moreover, administration of GSH resulted in the increase of DMAs percent in the liver and total arsenic in the blood. Increase of total arsenic in the blood was mainly due to the increase of DMAs. Findings from the present study suggested that administration of GSH or methionine might potentiate the methylation capacity of arsenic in both liver and extrahepatic tissues, which may facilitate the excretion of arsenic and decrease arsenic related toxicities in the body. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 361–366, 2010.
Performance evaluation of utility‐based scheduling schemes with QoS guarantees in IEEE 802.16/WiMAX systems
Authors: Pitic Razvan , Serrelli Federico , Redana Simone , Capone Antonio 
Published: May 2009

AbstractOne of the most important benefits that WiMAX technology brings, the ability to provide differentiated quality of service (QoS) guarantees, could also prove to be the largest problem for system designers, because scheduling mechanisms able to cope with these demands have not been explicitly defined in the standard. In order to facilitate the understanding of how various scheduling schemes perform in a real system, we present here a detailed performance evaluation of some utility‐based scheduling algorithms, covering aspects like fairness and QoS provisioning. Through a series of extensive simulations, we analyse the ability of the scheduling schemes considered to strike a balance between fairness among users, or more restrictively, user QoS requirement satisfaction, and system efficiency maximization. Further, we show how several simple algorithms could be used as building blocks, constructing a powerful mechanism that allows the system designer to obtain any desired system behaviour, or even to dynamically change from one profile to another, depending on specific network‐related conditions. More specifically, by combining the benefits of proportional fair (PF) scheduling with the highly desirable system capacity maximization, and also taking into account a peak‐to‐average (PTA) channel quality metric, we are able to define a rule that outperforms traditional scheduling schemes, copes with various network conditions and provides graceful service degradation. Our results indicate that, by exploiting the intrinsic properties of orthogonal frequency division multiple access (OFDMA) as well as the mechanisms of the WiMAX system that are not regulated by the standard, one could increase the system efficiency, while fully respecting the QoS guarantees imposed. The use of algorithms that provide graceful performance degradation is highly advisable, in order to be able to employ a non‐conservative call admission control (CAC) mechanism, which further improves the overall spectral efficiency by maintaining the system close to saturation at all times. Copyright © 2009 John Wiley & Sons, Ltd.
The Practice of Physical Medicine and Rehabilitation in subSaharan Africa and Antarctica: A White Paper or a Black Mark?
Authors: Haig Andrew J. , Im Jonathan , Adewole Ayodeji , Nelson Virgina S. , Krabak Brian ,   The International Rehabilitation Forum Commission on Physiatry in subSaharan Africa
Published: May 2009

ObjectiveThe medical specialty of physical medicine and rehabilitation (PM&R) has had a proven impact on persons with disability and on health care systems. Documents such as The White Book on Physical and Rehabilitation Medicine in Europe have been important in defining the scope of practice within various regions. However, on some continents, the practice has not been well defined.DesignTo explore the practice of PM&R in subSaharan Africa and Antarctica.MethodsMedline searches, membership data searches, fax survey of medical schools, Internet searches, and interviews with experts.ResultsThe continents are dissimilar in terms of climate and government. However both Antarctica and subSaharan Africa have no PM&R training programs, no professional organizations, no specialty board requirements, and no practicing physicians in the field. Because there are no known disabled children on Antarctica and adults are airlifted to world‐class health care, the consequences of this deficit are minimal there. However, the 788,000,000 permanent residents of subSaharan Africa, including approximately 78 million persons with disability, are left unserved.ConclusionsAntarctica is doing fine. Africa is in a crisis. Local medical schools, hospitals doctors, and persons with disability; along with foreign volunteers, aid groups, and policymakers can impact the crisis. However government—specifically national ministries of health—is ultimately responsible for the health and wellbeing of citizens.