bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of climatic factors in cyclic accelerated corrosion test towards the development of a reliable and repeatable accelerated corrosion test for the automotive industry
Authors: LeBozec N. , Thierry D.
Published: March 2010

Two designs of experiments made of nine accelerated tests each were used in order to study the influence of a selection of important climatic parameters such as the concentration of NaCl, the drying level, the basic humidity cycle, the frequency of salt spray and the temperature. The accelerated corrosion tests were all performed using automatic chambers. Different automotive materials were selected in order to study the resistance to cosmetic corrosion, perforation corrosion and bi‐metallic corrosion. For cosmetic materials, coated panels of cold rolled steel (CRS), zinc‐coated steel and aluminium alloys were chosen. Perforation corrosion was investigated using crevice panels of CRS, zinc‐coated steel or different grades of aluminium alloys. From the results, the influence of testing conditions on the cosmetic and perforation corrosion of different automotive materials was obtained. As an example, it was shown that an elevation of the temperature from 35 to 45 °C in the cyclic corrosion test increased the scribe creep on painted CRS and aluminium alloys while it has no significant effects on painted hot dip galvanized (HDG) panels. The results were also compared to that obtained after 2 years of exposure at a marine exposure site and on busses driving in area using de‐icing salt. It was shown that one of the tests performed gives a good correlation to field results.
Study on the corrosion behavior of NdFeB permanent magnets in nitric acid and oxalic acid solutions with electrochemical techniques
Authors: Zhang H. , Song Z. L. , Mao S. D. , Yang H. X.
Published: March 2010

Corrosion behavior of sintered NdFeB magnets in nitric acid and oxalic acid was investigated. The experiment results indicated that NdFeB is strongly corroded in nitric acid solution, and is passivated in oxalic acid solution. Based on the corrosion behavior, the possible corrosion mechanisms are discussed.
Adsorption effect of 1‐((2‐hydroxynaphtalen‐1‐yl) (phenyl)methyl)urea on the carbon steel corrosion in hydrochloric acid media
Authors: Hosseini S. M. A. , Bahrami M. J. , Pilvar P.
Published: March 2010

The adsorption effect of 1‐((2‐hydroxynaphtalen‐1‐yl)(phenyl)methyl)urea (HNPU) on corrosion behavior of carbon steel in 1 M hydrochloric acid solution was investigated using weight loss, potentiostatic polarization, and infrared spectroscopy methods. Surface morphology was studied by scanning electron microscopy (SEM). The experimental results, suggest that HNPU inhibited the corrosion of carbon steel in acid solution and the inhibition efficiencies increased as the concentration of the compound in the solution was increased. The calculated inhibition efficiencies from the two investigated methods were in good agreement. Potentiostatic polarization measurements indicate that HNPU acts as a mixed‐type inhibitor. The adsorption of the inhibitor on the carbon steel surface obeys Langmuir adsorption isotherm. The values of activation energy and the thermodynamic parameters, such as adsorption equilibrium constant (Kads), adsorption free energy (ΔGads), adsorption heat (ΔHads), and adsorption entropy (ΔSads) values were calculated and discussed. The results obtained from infrared spectra, confirmed the adsorption of inhibitor on the alloy surface after immersion in acidic solution containing HNPU. The SEM analysis indicated that there are more lightly corroded and oxidative steel surface for the specimens after immersion in acidic solution containing HNPU than that in blank.
Corrosion behavior of 3C magnesium alloys in simulated sweat solution
Authors: Wu F. , Zhang S. , Tao Z.
Published: March 2010

AZ series Mg alloys AZ31, AZ61, and AZ80 are widely applied in 3C (computer, communication, and consumer electronic) industry. Their corrosion characters in simulated sweat solution have been investigated by electrochemical technology, surface analysis, and pH measurements. Electrochemical test results showed that the three magnesium alloys revealed different corrosion resistance (Rt) in simulated sweat solution, Rt(AZ31) < Rt(AZ61) < Rt(AZ80). Three major components of simulated sweat solution played different roles during corrosion processes. Lactic acid was a kind of strong erosive medium for the magnesium alloys, and NaCl can induce pitting corrosion on alloys surface, while urea acted as a corrosion inhibitor. The corroded surface morphology of the three magnesium alloys was observed using scanning electron microscopy (SEM) and corrosion products were analyzed by X‐ray diffraction (XRD). Result of pH measurement tests showed that there were differences in climbing speed and final values of pH for the three magnesium alloys in simulated sweat solution.
Block Copolymer Micellar Nanoreactors for the Directed Synthesis of ZnO Nanoparticles
Authors: Braun Christoph H. , Richter Thomas V. , Schacher Felix , Müller Axel H. E. , Crossland Edward J. W. , Ludwigs Sabine
Published: March 2010

We report the simple one‐pot synthesis of size tunable zinc oxide nanoparticles (ZnO NPs) out of an organometallic ZnO precursor using the self‐assembly of solution phase polystyrene‐block‐poly(2‐vinylpyridine) micelles. The resulting hybrid material could be deposited on various substrates in a straightforward manner with the NPs showing size‐dependent absorption and photoluminescence due to the quantum‐size effect. We compare the results to the assembly of preformed NPs which are selectively incorporated in the poly(2‐vinylpyridine) core of the micelles due to the high affinity of ZnO to vinylpyridine.

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A Rapid and Facile Synthesis of Nanofibrillar Polyaniline Using Microwave Radiation
Authors: Gizdavic‐Nikolaidis Marija R. , Stanisavljev Dragomir R. , Easteal Allan J. , Zujovic Zoran D.
Published: March 2010

We present the first fast and facile microwave assisted synthesis of polyaniline (PANI) nanofibers (“MWA synthesis”). Under conventional synthesis (CS), the polymer was produced with 79.7% yield after 5 h at ambient temperature. However, under microwave irradiation, the nanofibers were produced with yield of 76.2% after only 5 min, i.e., with 78.8% after 20 min at ambient temperature. The FTIR and Raman spectra show the PANI structure in all samples either synthesized conventionally or in the microwave. SEM and TEM confirm the nanofibrillar morphology.

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The specific contributions of set‐shifting to freezing of gait in Parkinson's disease
Authors: Naismith Sharon L. , Shine James M. , Lewis Simon J.G.
Published: March 2010

Freezing of gait (FOG) in Parkinson's disease (PD) is common and the pathophysiology of FOG is poorly understood. It has been hypothesized to reflect complementary yet competing frontostriatal pathways that reduce the ability to keep different tasks (motor or cognitive) on‐line. This inability to “set‐shift” has been proposed to trigger a freezing episode. If correct, this hypothesis would predict a differential pattern of executive dysfunction with FOG being most specifically related to attentional set‐shifting. In this study, 31 patients with a range of self‐reported FOG symptom severities were administered tests of executive functioning. The results demonstrate that FOG symptoms were selectively correlated with poorer performance on tasks of set‐shifting, but not with a range of other executive tasks. This was apparent even after controlling for slowed processing speed, disease stage and depressive symptoms. The results support the recently proposed hypothesis for the pathophysiology underlying FOG in PD. © 2010 Movement Disorder Society
Characterization of Lewy body pathology in 12‐ and 16‐year‐old intrastriatal mesencephalic grafts surviving in a patient with Parkinson's disease
Authors: Li Jia‐Yi , Englund Elisabet , Widner Håkan , Rehncrona Stig , Björklund Anders , Lindvall Olle , Brundin Patrik
Published: March 2010

We previously reported the occurrence of Lewy bodies in grafted human fetal mesencephalic neurons in two patients with Parkinson's disease. Here, we have used immunohistochemistry and electron microscopy to characterize the development of Lewy bodies in one of these cases. This patient was operated in putamen on both sides at 12 or 16 years before death, respectively. We demonstrate that 2% of the 12‐year‐old and 5% of the 16‐year‐old grafted, presumed dopaminergic neurons contained Lewy bodies immunoreactive for α‐synuclein. Based on morphological analysis, two forms of α‐synuclein‐positive aggregates were distinguished in the grafts, the first a classical and compact Lewy body, the other a loose meshwork aggregate. Lewy bodies in the grafts stained positively for ubiquitin and thioflavin‐S, and contained characteristic α‐synuclein immunoreactive electron dense fibrillar structures on electron microscopy. Our data indicate that Lewy bodies develop gradually in transplanted dopaminergic neurons in a fashion similar to that in dopaminergic neurons in the host substantia nigra. © 2010 Movement Disorder Society
GLP‐1‐Mimetika in klinischen Studien. Therapie durch Aktivierung des GLP‐1‐Rezeptors
Authors: Ritzel Robert A.
Published: March 2010

Innovative Diabetesmedikamente müssen für die Patienten neben einer guten Kontrolle des Glucosestoffwechsels weitere Vorteile bereithalten. Die Krankheitsprogression sollte verlangsamt werden und langfristig sollte auch eine Reduktion diabetischer Komplikationen, kardiovaskulärer Ereignisse und der Mortalität resultieren. GLP‐1‐Mimetika sind genau mit diesem Anspruch angetreten und werden in den nächsten Jahren daran gemessen werden.
Antikörper statt Insulin?
Authors: Anders S. , Kühnemund L. , Stauch M. , Zündorf I. , Dingermann T.
Published: March 2010

Der Typ‐1‐Diabetes ist durch eine selektive und irreversible Destruktion der Insulin produzierenden Betazellen des Pankreas durch autoaggressive T‐Lymphozyten charakterisiert. Außerdem finden sich im Serum von betroffenen Individuen Autoantikörper gegen verschiedene Inselzellantigene.
The Natural History of Anencephaly
Authors: Obeidi Nidaa , Russell Noirin , Higgins John R , O'Donoghue Keelin
Published: March 2010

Objective

Early elective termination of pregnancy is the most common outcome of a diagnosis of anencephaly in developed countries. Experience and expertise with management of ongoing pregnancies is limited. We aimed to investigate the natural history of these pregnancies from diagnosis to delivery and to determine timing of death.

Method

A retrospective review of cases of anencephaly diagnosed between 2003 and 2009 in tertiary‐referral university teaching hospitals in Cork.

Results

The majority of cases (25/26; 96%) were diagnosed prenatally at a median gestation of 21+2 weeks (range 13+4–32+4). The median maternal age was 30 years (range 17–41) and 50% were primigravidae. Seven pregnancies were complicated by polyhydramnios and four deliveries were complicated by shoulder dystocia. The median gestation at delivery was 35 weeks (range 22+5–42+6); 69% of labours were induced at a median gestation of 34 weeks. Six women (6/26; 23%) had a pre‐labour intrauterine fetal death and nine women (9/26; 35%) had an intrapartum fetal death. Median neonatal survival time was 55 min (range 10 min to 8 days). Six parents donated neonatal organs for transplantation.

Conclusion

This study provides useful information for health professionals caring for patients with a diagnosis of anencephaly. The majority of these infants die prior to delivery but short‐term survival is possible. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of acetylene‐terminated monomers using a polymer‐supported palladium catalyst
Authors: Trumbo D. L. , Marvel C. S.
Published: March 2010

A single‐crysial polyethylene‐bound palladium catalys: was prepared and used in the synthesis of acelylene‐terminated monomers.
Dynamic dielectric analysis: Development of techniques for following the curing process of laminating polyester resins
Authors: Hoffman R. D. , Godfrey J. J. , Ehrig R. J. , Kranbuehl D. E. , Weller L. , Hoff M.
Published: March 2010

DDA measurements made over a wide frequency range with a novel sensor are used to determine the onset of reaction, variation in viscosity, onset of gel, and reaction completion in a series of peroxide‐initiated unsaturated polyester resins diluted in styrene monomer. The dielectric measurements provide detailed insights into (he the cure process not available by conventional thermographic techniques.
Is home spirometry useful in diagnosing asthma in children with nonspecific respiratory symptoms?
Authors: Brouwer Alwin F.J. , Visser Chantal A.N. , Duiverman Eric J. , Roorda Ruurd Jan , Brand Paul L.P.
Published: March 2010

Background

Variation of lung function is considered to be a hallmark of asthma. Although guidelines recommend measuring it as a diagnostic tool for asthma, the usefulness of this approach has not been studied in children.

Aim

To assess the usefulness of home spirometry in children with nonspecific lower respiratory tract symptoms, to diagnose or exclude asthma.

Methods

In school‐aged children, referred by their general practitioner because of chronic respiratory symptoms of unknown origin, the diagnosis of asthma was made or excluded by a pediatric pulmonologist (gold standard), based on international guidelines and a standardized protocol. Additionally, children measured peak expiratory flow (PEF) and forced expiratory flow in 1 sec (FEV1) twice daily for 2 weeks on a home spirometer, from which diurnal variation was calculated. These results (index test) were not revealed to the pediatric pulmonologist. The value of home spirometry to diagnose asthma was calculated.

Results

Sixty‐one children (27 boys) were included (mean age: 10.4 years; range: 6–16 years). Between asthma and no asthma, the mean difference in PEF variation was 4.4% (95% CI: 0.9–7.9; P = 0.016) and in FEV1 variation 4.5% (95% CI: 1.6–7.4; P = 0.003). Sensitivity and specificity, based on the 95th‐centile of the reference values for PEF and FEV1 variation (12.3% and 11.8%, respectively) were 50% and 72% for PEF variation and 45% and 92% for FEV1 variation. The likelihood ratio was 1.8 for PEF and 5.6 for FEV1.

Conclusions

The contribution of home spirometry in the diagnostic process for asthma in schoolchildren with nonspecific respiratory symptoms is limited. Pediatr Pulmonol. 2010; 45:326–332. © 2010 Wiley‐Liss, Inc.
A synergistic approach to protein crystallization: Combination of a fixed‐arm carrier with surface entropy reduction
Authors: Moon Andrea F. , Mueller Geoffrey A. , Zhong Xuejun , Pedersen Lars C.
Published: March 2010

Protein crystallographers are often confronted with recalcitrant proteins not readily crystallizable, or which crystallize in problematic forms. A variety of techniques have been used to surmount such obstacles: crystallization using carrier proteins or antibody complexes, chemical modification, surface entropy reduction, proteolytic digestion, and additive screening. Here we present a synergistic approach for successful crystallization of proteins that do not form diffraction quality crystals using conventional methods. This approach combines favorable aspects of carrier‐driven crystallization with surface entropy reduction. We have generated a series of maltose binding protein (MBP) fusion constructs containing different surface mutations designed to reduce surface entropy and encourage crystal lattice formation. The MBP advantageously increases protein expression and solubility, and provides a streamlined purification protocol. Using this technique, we have successfully solved the structures of three unrelated proteins that were previously unattainable. This crystallization technique represents a valuable rescue strategy for protein structure solution when conventional methods fail.
Urea denatured state ensembles contain extensive secondary structure that is increased in hydrophobic proteins
Authors: Nick Pace C. , Huyghues‐Despointes Beatrice M. P. , Fu Hailong , Takano Kazufumi , Scholtz J. Martin , Grimsley Gerald R.
Published: March 2010

The goal of this article is to gain a better understanding of the denatured state ensemble (DSE) of proteins through an experimental and computational study of their denaturation by urea. Proteins unfold to different extents in urea and the most hydrophobic proteins have the most compact DSE and contain almost as much secondary structure as folded proteins. Proteins that unfold to the greatest extent near pH 7 still contain substantial amounts of secondary structure. At low pH, the DSE expands due to charge–charge interactions and when the net charge per residue is high, most of the secondary structure is disrupted. The proteins in the DSE appear to contain substantial amounts of polyproline II conformation at high urea concentrations. In all cases considered, including staph nuclease, the extent of unfolding by urea can be accounted for using the data and approach developed in the laboratory of Wayne Bolen (Auton et al., Proc Natl Acad Sci 2007; 104:15317–15323).
Improving the built‐in potential of p‐i‐n amorphous silicon solar cells
Authors: Caputo D. , de Cesare G. , Tucci M.
Published: March 2010

In order to increase the built‐in voltage of hydrogenated amorphous silicon solar cells, in this work we exploit the use of very thin (<5 nm) high conductivity layers at the interfaces between the electrodes and the doped regions of an amorphous silicon n‐i‐p stacked structure. The idea starts from results of experiments showing that very thin chromium silicide layers, formed at room temperature after evaporation of chromium on amorphous silicon doped films, are able to reduce the activation energy to few meV in both kind of doped layers. The detailed structure of the proposed device is: glass substrate/bottom electrode/chromium silicide/n‐type‐intrinsic‐p‐type amorphous silicon layers/chromium silicide/top electrode. Simulation results obtained by a numerical device description and measurements of the current‐voltage characteristic under AM1.5G illumination condition, together with quantum efficiency curve, demonstrate the built‐in potential enhancement of the proposed solar cell structure with respect to identical structure without any chromium silicide layer. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic memory effect in a crystalline silicon/polyether heterostructure
Authors: Neitzert H.‐C. , Concilio S. , Iannelli P. , Vacca P.
Published: March 2010

Organic/inorganic heterojunctions have been fabricated by spin‐coating of an oxadiazole based polyether on top of either n‐type or p‐type crystalline silicon substrates. The prepared heterodiodes showed good rectification. During current‐voltage measurements sharp current switching effects have been observed in the reverse bias characteristics for both types of heterodiodes. In particular a very stable hysteresis in the reverse characteristics of the polyether/n‐type crystalline silicon has been measured at applied voltages below 1V. The application of this heterodiode as electrical memory with an on/off‐ratio of about 2 orders of magnitude has been demonstrated (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Amorphous silicon thin‐film solar cells deposited on flexible substrates using different zinc oxide layers
Authors: Alpuim P. , Samantilleke A. , Marins E. , Oliveira F. , Cerqueira M. F. , Rebouta L. , Stefanov S. , Chiussi S. , Serra C. , Bourée J.E.
Published: March 2010

In order to improve the transparent contact layer in amorphous silicon solar cells fabricated on low‐temperature plastic substrates, Al and Ga doped ZnO films were deposited at room temperature on plastic and glass and their optical, electronic and structural properties were correlated and optimized. Aiming to explore light trapping effects, plastic substrates were laser textured and their haze and total transmittance and reflectance were compared with those of untextured substrates. Although the haze increased dramatically, from 1.7 to 78.9%, the total transmittance of PET coated with ZnO:Ga decreased from 83.9%, in the untextured substrate, to 58.5% in the textured PET. The haze in reflected light of PET coated with Al increased from 4.3% to 66.2% after texturing but the total reflectance decreased from 70.1% to 36.8%. Therefore the untextured substrates were used in the solar cells. a‐Si:H solar cells were deposited at a substrate temperature of 150°C on plastic, in the superstrate p‐i‐n configuration, and on stainless steel, in the substrate n‐i‐p configuration. The efficiency is ∼5% in both types of devices, limited by low Jsc and low fill factor. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defects and structure of µc‐SiOx:H deposited by PECVD
Authors: Xiao Lihong , Astakhov Oleksandr , Carius Reinhard , Lambertz Andreas , Grundler Thomas , Finger Friedhelm
Published: March 2010

Electronic transport and paramagnetic defects detected by Electron Spin Resonance (ESR) in both intrinsic and ‐type silicon oxide prepared by PECVD were investigated. The structure and alloy composition of the material were varied all the way from microcrystalline silicon (µc‐Si:H) to amorphous silicon oxide (a‐SiOX:H). The transition‐phase‐mixture material is called “microcrystalline silicon oxide” (µc‐SiOX:H). In undoped samples we find a strong reduction of the dark conductivity from 10‐3to 10‐12 S/cm and an increase of the spin density from1017 to 3×1019 cm‐3 as the crystallinity decreases from 80% to 0%. The variation of the dark conductivity in phosphorous doped samples was even higher from 101 to 10‐12 S/cm. ESR spectra of intrinsic material consist of a single featureless line with g‐values in the range of 2.0043…2.005 depending on the structure and alloying. The spectra of ‐type material exhibit a broader range of g‐values of 1.998…2.0043 due to strong variations of the Fermi level over the entire crystallinity range. The results are discussed within the frame of current understanding of µc‐SiOX:H as a phase mixture of µc‐Si:H crystallites embedded in a‐SiOX:H matrix (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Paramagnetic states in µc‐SiC:H thin films prepared by Hot‐Wire CVD at low temperatures
Authors: Xiao Lihong , Astakhov Oleksandr , Carius Reinhard , Chen Tao , Wang Haiyan , Stutzmann Martin , Finger Friedhelm
Published: March 2010

The relationship between the structure, electrical conductivity and paramagnetic states in microcrystalline hydrogenated silicon carbide (µc‐SiC:H) prepared by HWCVD is investigated. The study includes undoped and Al‐doped (p ‐type) µc‐SiC:H of different crystalline volume fraction (ICIR). High densities of paramagnetic states are observed in undoped material over a wide range of crystallinity whereas the conductivity increases by 10 orders of magnitude up to 10‐2 S/cm as the material becomes more crystalline. This dramatic increase of the conductivity attributed to unintentional n ‐type doping has a clear effect on the ESR spectrum which changes from a broad featureless resonance in the low crystallinity material to a sharp line with a pair of distinct satellites in highly crystalline n ‐type µc‐SiC:H. Al‐doping results in compensation and then effective p ‐type doping in µc‐SiC:H at higher doping concentration. Al‐doping seems to hinder the crystalline growth in p ‐type µc‐SiC:H. For ICIR ≤ 20% the spin resonance signature is a broad (peak‐to‐peak linewidth ΔHpp ≈ 30 G) featureless slightly asymmetric line at g ≈ 2.01. The nature and behavior of the ESR spectra in different types of µc‐SiC:H are investigated with respect to the Fermi level position and crystalline volume fraction (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resistivity control of ZnO nanowires by Al doping
Authors: Zimmermann Gregor , Lange Martin , Cao Bingqiang , Lorenz Michael , Grundmann Marius
Published: March 2010

The resistivity of ZnO nanowires grown by pulsed laser deposition is found to decrease by more than two orders of magnitude to 10–1 Ω cm upon doping with aluminum in the 0.6 at% range. The growth morphology of the straight nanowires with hexagonal cross‐section and small tapering angle, typically below 0.5°, is similar for doped and undoped nanowires. Ohmic contacts to single nanowires were prepared by electron‐beam lithography. For a set of nanowires (diameter: 110–260 nm, length: 0.6–8 μm), the resistivity is found to be independent of length and diameter. This confirms the homogeneous electrical properties of the ZnO:Al nanowires in the given size regime. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The nature and magnitude of specific halogen bonds between iodo‐perfluorobenzene and heterocyclic systems
Authors: Lu Junming , Zhang Bo , Deng Qingming , Wang Jinan , Lu Yunxiang , Zhu Weiliang
Published: March 2010

In this work, first‐principle calculations at different levels of theory have been carried out to investigate a series of complexes formed between iodo‐perfluorobenzene and several heteroatomic rings. Such model systems are selected to mimic halogen bonding interactions experimentally found within supramolecular architectures. In all cases, the predicted intermolecular distances are significantly shorter than the sums of van der Waals radii of I and N (O or S) atoms and the interactions appear to be highly directional. Halogen bonding energies, calculated at the MP2/lan12dz level, are substantial, ranging from −2.50 to −7.53 kcal/mol. Given the strength as well as the directionality comparable to hydrogen bonds, these synthons should be of general use in many fields of chemistry. Finally, to gain more insights into the nature of such interactions, we have used the natural bond orbital and atoms in molecules analyses on the studied systems, which show a considerable magnitude of charge transfer, significant orbital interaction, and distinct bond critical points between the two interacting atoms. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study on the interaction of neutral and charged Tin (n = 1–7) clusters with one oxygen molecule
Authors: Cao Lu‐Jie , Ai Hong‐Qi , Zheng Li‐Ming , Wang Su‐Na , Zhou Mei‐Juan , Liu Ji‐Feng , Zhang Chong
Published: March 2010

The interactions between the neutral and charged (−2, −1, +1, and +2) Tin (n = 1–7) clusters and one O2 molecule were investigated by density functional theory. The calculated results show that the oxygen molecule is dissociative on the neutral Tin clusters. Geometrically, the two O atoms are distributed at the two sides across the neutral Tin cluster for n = 1–4 and the oxygen atom favors the three‐fold hollow site for n = 5, 6, and 7. The binding energy per atom (Eb) and energy gap (Egap) show higher stability and lower chemical activity of the neutral TinO2 (n = 1–7) systems compared with the corresponding Tin clusters. The adsorption energies (Ead) exhibit a continuously ascending tendency except for n = 4. The results of the addition of different charges (−2, −1, +1, and +2) on the most stable neutral TinO2 (n = 1–7) systems indicate that their geometries are usually perturbed. The stabilities of the neutral TinO2 systems are enhanced by adding one negative charge. The strongest interaction of the charged Tin clusters (−2, −1, +1, and +2) with O2 molecule is found at charge +2. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Systematic investigation of ion suppression and enhancement effects of fourteen stable‐isotope‐labeled internal standards by their native analogues using atmospheric‐pressure chemical ionization and electrospray ionization and the relevance for multi‐analyte liquid chromatographic/mass spectrometric procedures
Authors: Remane Daniela , Wissenbach Dirk K. , Meyer Markus R. , Maurer Hans H.
Published: March 2010

In clinical and forensic toxicology, multi‐analyte procedures are very useful to quantify drugs and poisons of different classes in one run. For liquid chromatographic/tandem mass spectrometric (LC/MS/MS) multi‐analyte procedures, often only a limited number of stable‐isotope‐labeled internal standards (SIL‐ISs) are available. If an SIL‐IS is used for quantification of other analytes, it must be excluded that the co‐eluting native analyte influences its ionization. Therefore, the effect of ion suppression and enhancement of fourteen SIL‐ISs caused by their native analogues has been studied. It could be shown that the native analyte concentration influenced the extent of ion suppression and enhancement effects leading to more suppression with increasing analyte concentration especially when electrospray ionization (ESI) was used. Using atmospheric‐pressure chemical ionization (APCI), methanolic solution showed mainly enhancement effects, whereas no ion suppression and enhancement effect, with one exception, occurred when plasma extracts were used under these conditions. Such differences were not observed using ESI. With ESI, eleven SIL‐ISs showed relevant suppression effects, but only one analyte showed suppression effects when APCI was used. The presented study showed that ion suppression and enhancement tests using matrix‐based samples of different sources are essential for the selection of ISs, particularly if used for several analytes to avoid incorrect quantification. In conclusion, only SIL‐ISs should be selected for which no suppression and enhancement effects can be observed. If not enough ISs are free of ionization interferences, a different ionization technique should be considered. Copyright © 2010 John Wiley & Sons, Ltd.
Lack of genotype effect on D1, D2 receptors and dopamine transporter binding in triple MOP‐, DOP‐, and KOP‐opioid receptor knockout mice of three different genetic backgrounds
Authors: Yoo Ji‐hoon , Bailey Alexis , Ansonoff Micheal , Pintar John E. , Matifas Audrey , Kieffer Brigitte L. , Kitchen Ian
Published: March 2010

We investigated D1, D2 receptors and dopamine transporter (DAT) binding levels in mice lacking all three opioid receptors and wild‐type (WT) mice on three different genetic backgrounds. Quantitative autoradiography was used to determine the level of radioligand binding to the D1 and D2 receptors and DAT labeled with [3H]SCH23390, [3H]raclopride, and [3H]mazindol, respectively in triple‐opioid receptor knockout (KO) and WT maintained on C57BL/6 (B6) and 129/SvEvTac (129) as well as C57BL/6 × 129/SvPas (B6 × 129) strains. No significant genotype effect was observed in D1, D2 receptors and DAT binding in any regions analyzed in any of the strains studied, suggesting that a lack of all three opioid receptors does not influence D1, D2 receptors and DAT expression, irrespective of their genetic strain background. However, strain differences were observed in D1 binding between the three strains of mice studied. Lower levels of D1 binding were observed in the substantia nigra of B6 × 129 WT mice compared with the 129 WT mice and in the olfactory tubercle of B6 × 129 WT compared with B6 WT and 129 WT mice. Lower levels of D1 binding were observed in the caudate putamen of B6 × 129 KO mice compared with 129 KO mice. In contrast, no significant strain differences were observed in D2 and DAT binding between the three strains of mice in any regions analyzed. Overall, these results indicate a lack of modulation of the dopaminergic system by the deletion of all three opioid receptors regardless of different background strains. Synapse 64:520–527, 2010. © 2010 Wiley‐Liss, Inc.
Hydrocinchonine, cinchonine, and quinidine potentiate paclitaxel‐induced cytotoxicity and apoptosis via multidrug resistance reversal in MES‐SA/DX5 uterine sarcoma cells
Authors: Lee Sang‐Yun , Rhee Yun‐Hee , Jeong Soo‐Jin , Lee Hyo‐Jeong , Lee Hyo‐Jung , Jung Min‐Hyung , Kim Sun‐Hyung , Lee Eun‐Ok , Ahn Kwang Seok , Ahn Kyoo Seok , Kim Sung‐Hoon
Published: March 2010

Multidrug resistance (MDR) is one of important issues to cause the chemotherapy failure against cancers including gynecological malignancies. Despite some MDR reversal evidences of natural compounds including quinidine and cinchonine, there are no reports on MDR reversal activity of hydrocinchonine with its analogues quinidine and cinchonine especially in uterine sarcoma cells. Thus, in the current study, we comparatively investigated the potent efficacy of hydrocinchonine and its analogues quinidine and cinchonine as MDR‐reversal agents for combined therapy with antitumor agent paclitaxel (TAX). Hydrocinchonine, cinchonine, and quinidine significantly increased the cytotoxicity of TAX in P‐glycoprotein (gp)‐positive MES‐SA/DX5, but not in the P‐gp‐negative MES‐SA cells at nontoxic concentrations by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐‐diphenyltetrazolium bromide (MTT) assay. Rhodamine assay also revealed that hydrocinchonine, cinchonine, and quinidine effectively enhanced the accumulation of a P‐gp substrate, rhodamine in TAX‐treated MES‐SA/DX5 cells compared with TAX‐treated control. In addition, hydrocinchonine, cinchonine, and quinidine effectively cleaved poly (ADP‐ribose) polymerase (PARP), activated caspase‐3, and downregulated P‐gp expression as well as increased sub‐G1 apoptotic portion in TAX‐treated MES‐SA/DX5 cells. Taken together, hydrocinchonine exerted MDR reversal activity and synergistic apoptotic effect with TAX in MES‐SA/DX5 cells almost comparable with quinidine and cinchonine as a potent MDR‐reversal and combined therapy agent with TAX. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.
Genotoxic effects of chlorpyrifos, cypermethrin, endosulfan and 2,4‐D on human peripheral lymphocytes cultured from smokers and nonsmokers
Authors: Sandal Suleyman , Yilmaz Bayram
Published: March 2010

Pesticides often cause environmental pollution and adverse effects on human health. We have chosen four structurally different pesticides (endosulfan, an organochlorine pesticide; chlorpyrifos, an organophosphate insecticide; cypermethrin, type II pyrethroid insecticide, and 2,4‐dichlorophenoxyacetic acid, a chlorinated aromatic hydrocarbon acid pesticide) to examine and compare their effects on DNA damage in acutely cultured human lymphocytes by the comet assay. In addition, possible differences in response between smoking and nonsmoking subjects were also investigated. Venous blood samples were obtained from healthy male nonsmoker (n= 7) and smoker (n= 8) donors. Primary cultures of lymphocytes were prepared and test groups were treated with three different concentrations (1, 5, and 10 μM) of endosulfan, chlorpyrifos, cypermehrin, and 2,4‐D. DNA damage was assessed by alkaline comet assay. We determined an increase in the ratio of DNA migration in human lymphocyte cell cultures as a result of treatment with cypermethrin, 2,4‐D and chlorpyrifos at high concentration. Endosulfan had no significant genotoxic effect even at 10 μM concentration. We suggest that chlorpyrifos and cypermethrin are more potentially genotoxic than endosulfan and 2,4‐D. Our findings also indicate that the only significant DNA damage between smokers and nonsmokers was observed in the 2,4‐D‐treated group. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.
Incorporation of femur length leads to underestimation of fetal weight in asymmetric preterm growth restriction
Authors: Proctor L. K. , Rushworth V. , Shah P. S. , Keunen J. , Windrim R. , Ryan G. , Kingdom J.
Published: March 2010

Objective

To review the performance of a variety of biometry formulae for estimated fetal weight (EFW) in the management of severely growth restricted fetuses with abnormal umbilical artery Doppler at a single perinatal institution.

Methods

Forty‐three pregnancies were retrospectively reviewed. Inclusion criteria were: chromosomally/ structurally normal fetus; complete ultrasound biometry at ≤ 7 days from delivery; EFW < 10th centile; absent/reversed end‐diastolic flow in the umbilical arteries; and delivery at < 32 + 6 weeks. EFW accuracy and precision were compared among nine formulae utilizing combinations of head circumference (HC), biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) measurements.

Results

Twenty‐six (60.5%) fetuses showed asymmetric growth (HC/AC ratio > 95th centile). Analysis of the systematic and random errors associated with each formula showed that the birth weight of asymmetrically‐grown fetuses was most closely approximated by the Hadlock equation that utilized BPD and AC measurements only. The birth weight of symmetrically‐grown fetuses was most closely approximated by EFW derived from Hadlock equations that utilized ≥ three biometry measurements, including FL. Incorporation of FL into Hadlock formulae led to significant underestimation of birth weight in the fetuses with asymmetric growth (mean percentage error ± SD: EFWFL–AC, −13.3 ± 9.8%; EFWBPD–FL–AC, −10.8 ± 9.8%; EFWHC–FL–AC, −11.8 ± 9.3%; EFWBPD–HC–FL–AC, −11.7 ± 9.5%; P < 0.001). The same equations were accurate in fetuses with symmetric growth (EFWFL–AC, 3.1 ± 10.0%; EFWBPD–FL–AC, 1.0 ± 8.9%; EFWHC–FL–AC, 0.3 ± 8.7%; EFWBPD–HC–FL–AC, 0.4 ± 15.5%). Use of the best performing equation (Hadlock 3), which does not include FL, to estimate weight in asymmetrically‐grown fetuses over 28 weeks' gestation, would have reduced the proportion of those with an underestimation of fetal weight of > 100 g from nine (50.0%) to three (16.7%).

Conclusions

Biometry methods that exclude FL should be considered in asymmetric intrauterine growth restriction associated with abnormal umbilical artery Doppler waveforms. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
A survey on the channel assignment problem in wireless networks
Authors: Audhya Goutam K. , Sinha Koushik , Ghosh Sasthi C. , Sinha Bhabani P.
Published: March 2010

Efficient allocation of channels for wireless communication in different network scenarios has become an extremely important topic of recent research. The main challenge lies in the fact that the channel allocation problem is NP‐complete. Because of a maximum allowable time limit imposed in practical situations for allocation of channels, sometimes we may need to be satisfied with a near‐optimal solution. In this correspondence, we present a discussion on the various challenges and approaches that have been used by different researchers to solve the problem of channel allocation taking into account different interference issues and efficient utilization of available communication channels for cellular mobile (including multimedia communication) environment and cognitive radio based networks. Copyright © 2010 John Wiley & Sons, Ltd.
A novel elliptical curve ID cryptography protocol for multi‐hop ZigBee sensor networks
Authors: Kim Hyunjue , Kim Chang Hyun , Chung Jong‐Moon
Published: March 2010

ZigBee uses the network security and application profile layers of the IEEE 802.15.4 and ZigBee Alliance standards for reliable, low‐powered, wireless data communications. However, the ZigBee protocol has some security weaknesses for newly joining devices. In this paper, these weaknesses are analyzed and a novel elliptical curve identity‐based cryptography (ECIC) protocol is presented to improve the security level of ZigBee networks. The proposed method provides perfect forward secrecy and enables network key transmission between nodes. Therefore, the traffic concentrated on the trustcenter is diminished, and the network efficiency is improved by reducing the key establishment time and processing burden on each sensor node, thereby reducing the overall energy consumption of the sensor network. Copyright © 2010 John Wiley & Sons, Ltd.
Ockham's Razor
Authors: Lazar Nicole
Published: March 2010

Ockham's Razor is the philosophical principle that entities or assumptions should not be introduced unnecessarily. This is often interpreted as stating that one should seek the simplest explanation for a phenomenon. The purposes of this note are to introduce some of the different formulations of the Razor and the controversy surrounding it, to explore the use of Ockham's Razor as a scientific tool, and to draw connections with statistical inference, both frequentist and Bayesian. The note starts with a brief introduction to the life of William of Ockham, to whom the Razor is traditionally and popularly attributed. There is some controversy regarding the use of Ockham's Razor as an inferential tool; this seems to center on the meaning of ‘simple explanation’ and the issue is explored. Uses of the Razor in science, in statistical model selection, and in Bayesian inference are examined. Copyright © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Modeling Methods and Algorithms

Statistical Models > Model Selection
Clausius‐Clapeyron relations for an evaporating solid conductor
Authors: Grinfeld P.
Published: March 2010

We propose a number of experiments designed to test Thomson's thermodynamic theory of nucleation in the presence of electrostatic fields. In each proposed experiment, a two‐phase system is kept inside a charged capacitor whose top plate can act as a piston imposing external pressure. We present Clausius‐Clapeyron relations for a number of scenarios. In particular, we show the unexpected result that if the voltage U is changed isothermally and isobarically, then the accumulated charge τ remains unchanged.
Science de l'homme et division des sciences selon Maine de Biran
Authors: Azouvi François
Published: March 2010

Comme beaucoup de ses contemporains, Maine de Biran s’attache tout au long de sa carrière philosophique à élaborer une «science de l’homme». Mais l’originalité de la science biranienne de l’homme est d’être construite selon une perspective résolument épistémologique. Il y a autant de sciences dans la science de l’homme qu’il y a de « points de vue » pour l’esprit; chacun détermine un « ordre de faits », se déploie selon une méthode propre, atteint des résultats spécifiques et rencontre des obstacles particuliers. La division des sciences est donc la tâche qui prélude à l’analyse de chacune d’elles; c’est elle qui occupe Maine de Biran à chacun des moments clés de son itinéraire.
Enseignement scientifique et lignes de partage disciplinaire
Authors: Hulin Nicole
Published: March 2010

L’organisation de l’enseignement sdentifique s’effectue en suivant un découpage disciplinaire et la spécialisation des études impose des choix de couplage entre disciplines. Ainsi, apparaît un souci de classification dans la définition du domaine de chacune des disciplines de même que dans l’explidtation de leurs dépendances mutuelles. En France, la physique occupe une place charnière, éclatée en une physique expérimentale liée à la chimie et une physique mathématique rattachée aux sciences mathématiques; quant aux mathématiques, elles sont considérées comme un instrument nécessaire dans l’acquisition des connaissances scientifiques.
Postsurgical Recurrence of Ileal Crohn’s Disease: An Update on Risk Factors and Intervention Points to a Central Role for Impaired Host‐Microflora Homeostasis
Authors: Cunningham Michael F. , Docherty Neil G. , Coffey J. Calvin , Burke John P. , O’Connell P. Ronan
Published: March 2010

Background

A pressing need exists to identify factors that predispose to recurrence after terminal ileal resection for Crohn’s disease (CD) and to determine effective prophylactic strategies. This review presents an up‐to‐date summary of the literature in the field and points to a role for bacterial overproliferation in recurrence.

Methods

The literature (Medline, Embase, and the Cochrane Library, 1971–2009) on ileal CD and postoperative recurrence was searched, and 528 relevant articles were identified and reviewed.

Results

Smoking is a key independent risk factor for recurrence. NOD2/CARD15 polymorphisms and penetrating phenotype are associated with aggressive disease and higher reoperation rates. Age at diagnosis, disease duration, gender, and family history are inconsistent predictors of recurrence. Prophylactic 5‐aminosalicylic acid therapy and nitromidazole antibiotics are beneficial. Combination therapies with immunosuppressants are also effective. Anti‐TNFα‐based regimens show benefit but the evidence base is small. Corticosteroid, interleukin‐10, and probiotic therapies are not effective. Wider, stapled anastomotic configurations are associated with reduced recurrence rates. Strictureplasty and laparoscopic approaches have similar long‐term recurrence rates to open resection techniques. Length of resection and presence of microscopic disease at resection margins do not influence recurrence. A lack of consensus exists regarding whether the presence of granulomas or plexitis affects outcome.

Conclusions

Current evidence points to defects in mucosal immunity and intestinal dysbiosis of either innate (NOD2/CARD15) or induced (smoking) origin in postoperative CD recurrence. Prophylactic strategies should aim to limit dysbiosis (antibiotics, side‐to‐side anastomoses) or prevent downstream chronic inflammatory sequelae (anti‐inflammatory, immunosuppressive, and immunomodulatory therapy).
Amylase Concentration of the Drainage Fluid as a Risk Factor for Intra‐abdominal Abscess Following Gastrectomy for Gastric Cancer
Authors: Iwata Naoki , Kodera Yasuhiro , Eguchi Takehiko , Ohashi Norifumi , Nakayama Goro , Koike Masahiko , Fujiwara Michitaka , Nakao Akimasa
Published: March 2010

Background

Insertion of drainage tubes at gastric cancer surgery could be useful for the prediction and management of postoperative complications. However, drains should be removed as soon as they are deemed unnecessary for various reasons. Amylase concentration of the drainage fluid following total gastrectomy for gastric cancer has been reported to be a useful risk factor for surgical complications.

Methods

Between January 2002 and December 2008, the authors measured amylase concentration of the drainage fluid on the first postoperative day for 372 patients who underwent gastrectomy with lymphadenectomy for gastric cancer at the Department of Surgery II, Nagoya University. Univariate and multivariate analyses were performed to evaluate the significance of various covariates as risk factors for the pancreas‐related complications.

Results

Postoperative complications developed in 111 patients, of which 27 were pancreas‐related. Amylase concentration was significantly higher in patients who underwent splenectomy, pancreaticosplenectomy, total/proximal gastrectomies, and extended lymphadenectomy and in those who eventually developed intra‐abdominal abscess. Amylase concentration ≥1,000 IU/l on the first postoperative day, along with the body mass index, was an independent risk factor for pancreas‐related intra‐abdominal abscess.

Conclusions

With a negative predictive value of 97.7%, pancreas‐related complications are highly unlikely to be observed when amylase concentration is less than 1,000 IU/l, and early removal of the drainage tube could be recommended for these patients.