bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studying conductive polymer coating (BAM‐PPV) using positron annihilation spectroscopy
Authors: Zhang Renwu , Johnson Paul M. , Deluca Ryan J. , Alger Terry D. , Xu Jun , Suzuki R. , Ohdaira T. , Jean Y. C. 
Published: August 2007

AbstractPositron annihilation spectroscopy has been used to study two conductive polymer coatings, Al‐507A and Al‐507B, consisting of BAM‐PPV (poly (bis‐dialkylamino) phenylene vinylene) dissolved in two different solvents, THF at 0.2% concentration and xylene at 1.0% concentration, respectively. These samples were sprayed on aluminum substrates. They were further subjected to neutral salt treatment for 240 hours for the corrosion test. Doppler broadening of annihilation radiation (DBAR) and positron annihilation lifetime spectroscopy (PALS) were employed to investigate the corrosion effect on the two coatings in addition to their free volume. It was found that there are two layers in the polymer topcoat of sample Al‐507A while they were not clearly seen in Al‐507B. Interestingly the near‐surface layer demonstrates a large change after the salt treatment, suggesting creation of extra free volume. Both DBAR and PALS measurements indicate that the amount of free volume for Al‐507B coating is more than that for Al‐507A coating, while the free‐volume hole size for both coatings are similar, around 0.32 nm. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron annihilation in three zirconia polymorphs
Authors: Melikhova O. , Kuriplach J. , Čížek J. , Procházka I. , Anwand W. , Brauer G. , Konstantinova T. E. , Danilenko I. A. 
Published: August 2007

AbstractPositron lifetimes and high momentum profiles both for the perfect lattice and selected defects are calculated in three (cubic, tetragonal and monoclinic) zirconia polymorphs using the atomic superposition method. Theoretical data are compared with the measured positron lifetime for cubic and tetragonal monocrystals of yttria‐stabilized zirconia (YSZ) and coincidence Doppler broadening measurements on tetragonal monocrystals of YSZ. Positron lifetime spectra of YSZ monocrystals exhibit a single component spectrum with lifetimes 178 ps and 174 ps for cubic and tetragonal phases, respectively. Possible interpretations of measured lifetime and Doppler data are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase transition studies in trans ‐stilbene crystal using 2D‐ACAR
Authors: Sivaji K. , Arul Chakkaravarthi A. , Selvakumar S. , Sankar S. 
Published: August 2007

AbstractTwo‐dimensional electron momentum distributions (EMD) mapping in a (c‐a) plane of molecular trans‐stilbene crystal have been made, using the two‐dimensional angular correlation of positron annihilation radiation (2D‐ACAR) at room temperature (RT), 210 K and 110 K. Further, we discuss the changes in static and dynamic electron momentum distribution and the positron behavior in molecular crystals at different temperatures to clarify their static and dynamic origin. An attempt has been made to visualize the electronic structure of organic molecular crystal trans‐stilbene during phase transition. The mapped EMD is explained with the combination of disordered to ordered transition concept and molecular vibration freezing model. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of columbite ceramics A1–xNb2O6 by positron annihilation spectroscopy
Authors: Grebennikov Dmytro , Ovchar Oleg , Neretina Svetlana , Belous Anatolii , Mascher Peter 
Published: August 2007

AbstractColumbite ceramics A1–xNb2O6 (where A = Mg, Co, Zn and x = 0, ‐0.005, ‐0.01, ‐0.03, ‐0.04) were studied by means of positron annihilation spectroscopy. The lifetime spectra revealed the presence of two lifetime components. The first component originates from positron annihilation inside of the grains. The second component is due to annihilations in the grain boundary regions. From the intensity of the second component and simulations (C. Hübner, T. Staab, and R. Krause‐Rehberg, Appl. Phys A 61, 203 (1995) [1]) the diameter of the grains is estimated as 2‐5 μm, ∼ 10 μm and 5‐7 μm, respectively for Mg‐, Co‐, and Zn‐containing columbites, in agreement with the results of microscopy measurements. In order to facilitate explanation of experimental results, theoretical calculations were conducted on columbite samples. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorbed hydrogen on Ni(111) surface studied by slow positron beam
Authors: Hirota K. , Osawa M. , Suzuki H. , Oishi Y. , Kanazawa I. , Fukutani K. , Nozawa K. , Komori F. 
Published: August 2007

AbstractReemitted slow positrons from clean Ni(111) surface and hydrogen‐adsorbed Ni(111) one have been measured. We have estimated experimentally the positron work functions, ‐0.60±0.05 and ‐0.82±0.07 eV of clean Ni(111) surface and the hydrogen‐adsorbed Ni(111) surface, respectively. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Fe‐doping and electrical load on the defect structure of Pb(ZrxTi1–x)O3 ferroelectric ceramics
Authors: Puff W. , Balke N. , Kungl H. , Hoffmann M. J. , Balogh A. G. 
Published: August 2007

AbstractVacancy related defects in undoped and 1 mol% Fe doped Pb(Zr54Ti46)O3 ferroelectric ceramic samples have been investigated by means of positron lifetime spectroscopy. Temperature dependent measure‐ments between 10 K and room temperature have been performed to study the influence of the acceptor type doping on the defect structure and on the charge states of the defects. On commercial Pb(Zr0.54Ti0.47(Ni0.33Sb0.67)0.08)O3 samples the influence of different electrical loading have been studied. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vacancy‐induced minority‐spin states in half‐metallic Heusler alloys
Authors: Özdoğan Kemal , Şaşıoğlu Ersoy , Galanakis Iosif 
Published: August 2007

AbstractFerromagnetic full Heusler alloys containing Co are amongst the most studied half‐metallic systems. Several studies recently have been concentrated on the effect of defects and impurities. We focus in this Letter on the case of vacancies in these alloys. We show that the occurrence of vacancies at the sites occupied by Co atoms can destroy half‐metallicity and alters the Slater–Pauling rule. Such defects are likely to occur since they result to the C1b lattice structure of the semi‐Heusler alloys. Contrary, the appearance of vacancies at the other sites keeps the half‐metallic character of the parent alloys. Thus for realistic devices it is important to prevent the appearance of vacancies during the growth of thin films. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐Abelian homomorphism testing, and distributions close to their self‐convolutions
Authors: Ben‐or Michael , Coppersmith Don , Luby Mike , Rubinfeld Ronitt 
Published: August 2007

AbstractIn this paper, we study two questions related to the problem of testing whether a function is close to a homomorphism. For two finite groupsG,H(not necessarily Abelian), an arbitrary mapf:G,H, and a parameter 0 <ε< 1, say thatfisε‐close to a homomorphism if there is some homomorphismgsuch thatgandfdiffer on at mostε|G| elements ofG, and say thatfisε‐far otherwise. For a givenfandε, a homomorphism tester should distinguish whetherfis a homomorphism, or iffisε‐far from a homomorphism. WhenGis Abelian, it was known that the test which picksO(1/ε) random pairsx,yand tests thatf(x) +f(y) =f(x+y) gives a homomorphism tester. Our first result shows that such a test works for all groupsG.Next, we consider functions that are close to their self‐convolutions. LetA= {ag|gεG} be a distribution onG. The self‐convolution ofA,A′= {a|gεG}, is defined byIt is known thatA=A′exactly whenAis the uniform distribution over a subgroup ofG. We show that there is a sense in which this characterization is robust—that is, ifAis close in statistical distance toA′, thenAmust be close to uniform over some subgroup ofG.Finally, we show a relationship between the question of testing whether a function is close to a homomorphism via the above test and the question of characterizing functions that are close to their self‐convolutions. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
The random planar graph process
Authors: Gerke Stefanie , Schlatter Dirk , Steger Angelika , Taraz Anusch 
Published: August 2007

AbstractWe consider the following variant of the classical random graph process introduced by Erdős and Rényi. Starting with an empty graph on n vertices, choose the next edge uniformly at random among all edges not yet considered, but only insert it if the graph remains planar. We show that for all ε > 0, with high probability, θ(n2) edges have to be tested before the number of edges in the graph reaches (1 + ε)n. At this point, the graph is connected with high probability and contains a linear number of induced copies of any fixed connected planar graph, the first property being in contrast and the second one in accordance with the uniform random planar graph model. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Octylphenol reduces the expressions of steroidogenic enzymes and testosterone production in mouse testis
Authors: Kim Suel‐Kee , Kim Jong‐Hoon , Lee Ho‐Joon , Yoon Yong‐Dal 
Published: August 2007

Abstract4‐tert‐octylphenol (OP) is known to disrupt testicular development and reduce male fertility. In the present study, male mice were exposed to OP at two different developmental stages, and the expression of steroidogenic enzymes and testosterone production were evaluated. Juvenile (15‐day‐old) and adult (8‐week‐old) male mice were injected with 2, 20, or 200 mg/kg of OP or 0.2 μg/kg of estradiol valerate for 5 days. Testosterone concentration was measured by radioimmunoassay and the expressions of the testicular genes were determined by RT‐PCR analysis and immunohistochemistry. In the animals exposed with 20 mg/kg of OP during juvenile stage, histochemical analysis of the testis showed that number of pyknotic germ cells inside the tubule was increased, while the number of oil red O positive Leydig cells was decreased. Moreover, the lumen formation was remarkably delayed. A reduced serum testosterone concentration and down‐regulated expressions of the mRNAs for steroidogenic acute regulatory protein (StAR), cholesterol side‐chain cleavage enzyme (P450scc), and 17α‐hydroxylase/C17–20 lyase (P45017α) were also observed after juvenile exposure to OP. Immunohistochemical staining for P450scc was mainly detected in interstitial Leydig cells, and a slightly reduced expression of P450scc protein was observed in the testis exposed to 20 mg/kg of OP during juvenile stage. The present study demonstrates that juvenile exposure to OP inhibits steroidogenesis by decreasing the expressions of steroidogenic enzymes in the testis. Diminished lipid content in Leydig cells and reduced transcriptional expression of the cholesterol transport gene, StAR, also support altered cholesterol metabolism and/or transport as a potential mechanism for the decreased testosterone production following exposure to OP. Altogether, the alteration of steroidogenesis by exposure to OP may adversely affect the normal development of the testis and spermatogenesis. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 449–458, 2007.
Serologic evaluation of human microcystin exposure
Authors: Hilborn E. D. , Carmichael W. W. , Soares R. M. , Yuan M. , Servaites J. C. , Barton H. A. , Azevedo S. M. F. O. 
Published: August 2007

AbstractMicrocystins are among the most commonly detected toxins associated with cyanobacteria blooms worldwide. Two episodes of intravenous microcystin exposures occurred among kidney dialysis patients during 1996 and 2001. Analysis of serum samples collected during these episodes suggests that microcystins are detectable as free and bound forms in human serum. Our goal was to characterize the biochemical evidence for human exposure to microcystins, to identify uncertainties associated with interpretation of these observed results, and to identify research needs. We analyzed serum samples using enzyme‐linked immunosorbent assay (ELISA) methods to detect free microcystins, and gas chromatography/mass spectrometry (GC/MS) to detect 2‐methyl‐3‐methoxy‐4‐phenylbutyric acid (MMPB). MMPB is derived from both free and protein‐bound microcystins by chemical oxidation, and it appears to represent total microcystins present in serum. We found evidence of free microcystins in patient serum for more than 50 days after the last documented exposure. Serum concentrations of free microcystins were consistently lower than MMPB quantification of total microcystins: free microcystins as measured by ELISA were only 8–51% of total microcystin concentrations as detected by the GC/MS method. After intravenous exposure episodes, we found evidence of microcystins in human serum in free and protein‐bound forms, though the nature of the protein‐bound forms is uncertain. Free microcystins appear to be a small but variable subset of total microcystins present in human serum. Research is needed to elucidate the human toxicokinetics of microcystins, in part to determine how observed serum concentrations can be used to estimate previous microcystin exposure. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 459–463, 2007.
Seasonal evaluation of reproductive status and exposure to environmental estrogens in hornyhead turbot at the municipal wastewater outfall of Orange County, CA
Authors: Deng Xin , Rempel Mary Ann , Armstrong Jeff , Schlenk Daniel 
Published: August 2007

AbstractSeasonal changes in developmental stages, condition factor (CF), gonadosomatic index, and plasma vitellogenin (Vtg) concentrations in male and female hornyhead turbot were examined at the wastewater outfall (T1) of the Orange County Sanitation District, and two farfield sites T11 (7.7 km northwest of the outfall) and Dana Point (35 km south of the outfall) between February 2005 and May 2006. Fish collected from the three sites exhibited male‐oriented sex ratios. With few exceptions, developmental stages, CF, and GSI of both genders and plasma Vtg concentrations of females were not significantly different in samples collected from different sites at the same sampling period. More advanced gonad developmental stages and higher plasma Vtg concentrations in females were observed in August, indicating the seasonality of the reproductive cycle for this species. Plasma Vtg concentrations in males were observed in all of the sampling sites with the highest prevalence at T11 relative to T1 and Dana Point. The Vtg expression in males from the three sampling sites indicated widespread exposure to estrogenic compounds in waters of coastal California. However, the histopathological and reproductive relevance of the responses appeared to be insignificant and may not affect the population in these locations. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 464–471, 2007.
Acute toxicities of trace metals and common xenobiotics to the marine copepod Tigriopus japonicus: Evaluation of its use as a benchmark species for routine ecotoxicity tests in Western Pacific coastal regions
Authors: Lee K.‐W. , Raisuddin S. , Hwang D.‐S. , Park H. G. , Lee J.‐S. 
Published: August 2007

AbstractMarine copepods have recently been recognized as important organisms in ecotoxicity testing for regulatory purposes. The harpacticoid copepod Tigriopus japonicus has a wide geographical distribution along the coast in the Western Pacific including Japan, South Korea, Taiwan, and Hong Kong. This study evaluated the acute toxicity sensitivity profile of Tigriopus japonicus against 12 common toxic substances including six endocrine disrupting chemicals (EDCs), three biocides and three trace metals. Through standard acute toxicity test procedures, toxicity endpoints LC50, LC10, and no observed effect concentration (NOEC) of each chemical were obtained. Although T. japonicus depicted different sensitivities towards different chemicals, a dose‐response relationship was consistent in all cases. T. japonicus was particularly sensitive to most of the EDCs, but relatively less sensitive to molinate (a thiocarbate herbicide). Across all tested chemicals, tributyltin (TBT) was the most toxic to the copepod with the LC50, LC10, and NOEC of 0.05, 0.03, and 0.02 mg/L, respectively. A comparison made with available data on acute toxicities of these chemicals to other marine copepod species revealed that T. japonicus is generally more sensitive to EDCs and in particular to TBT. We, therefore, strongly advocate that T. japonicus shall be adopted as a benchmark marine species for routine ecotoxicity testing and ecotoxicological studies in Western Pacific coasts. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 532–538, 2007.
Release of hydrogen sulfide by asteroidimpacts in black sea and risks for inland human population
Authors: Badescu Viorel 
Published: August 2007

AbstractThe hydrogen sulfide rich waters of the Black Sea pose a potential danger for the surrounding land regions. The impact of an asteroid may cause a catastrophic poisonous gas release in the atmosphere. Some effects of this last phenomenon on the Eastern Black Sea coastal regions are evaluated in this article. Two simple models are proposed to describe the generation of the H2S cloud. The initial diameter of the cloud depends on asteroid size. The initial thickness of the cloud depends, in addition, on sea depth at impact location. The wind speed plays an important role in H2S cloud dynamics. At 10 m/s wind‐speed the cloud margins may be seen at about 150 km from impact location in about 3.2 h. The maximum distance traveled by the hydrogen sulfide cloud increases by increasing the asteroid size and wind speed. The influence of the impact position on the distance traveled by hydrogen sulfide clouds is rather weak, as far as the seawater depth does not change significantly. Two values are considered when referring to the effect of hydrogen sulfide concentrations on humans: the lower concentration limit of 19.88 ppm (which corresponds to fatigue, loss of appetite, headache, irritability, poor memory, dizziness) and the upper concentration limit of 497 ppm (which corresponds to death after single exposures). The land surface area covered by the H2S cloud generated by a 1000 m size asteroid during the run‐in ranges between about 6080 and 11 520 km2. This may affect between 145 000 and 276 000 people. When a 250 m size asteroid is considered, the covered land surface area ranges between about 840 and 1890 km2 and between 20 000 and 45 000 people may be affected. In case of a 70 m size asteroid, the cloud covers up to 105 km2 of land during the run‐in. This may affect about 2500 people. These are moderate estimates. They do not include the urban population and may be 10 times underestimated for some particular wind directions. General recommendations to diminish the social effects of the impacts are presented. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 510–524, 2007.
Levator co‐activation is a significant confounder of pelvic organ descent on Valsalva maneuver
Authors: Örnö A. K. , Dietz H. P. 
Published: August 2007

AbstractObjectiveA Valsalva maneuver is used clinically and on imaging in order to determine female pelvic organ prolapse. We have examined the potential confounding effect of levator co‐activation at the time of a Valsalva maneuver and the impact of repetition with biofeedback instruction.MethodsFifty nulliparous women at 36–38 weeks' gestation received 3D/4D translabial ultrasound investigation in the dorsal resting position after bladder emptying. Valsalva maneuvers were recorded initially and after repeated attempts with visual biofeedback both during the maneuver and after, with the operator demonstrating findings on the ultrasound monitor, in order to abolish levator co‐activation. Offline analysis was subsequently undertaken.ResultsSignificant differences between first and optimal Valsalva maneuver were found for bladder neck position, bladder neck descent, hiatal sagittal diameter and hiatal area on Valsalva. In a minority of women (22/50) we observed a reduction in the sagittal hiatal diameter on first Valsalva maneuver, indicating levator co‐activation. A reduction in sagittal diameter was seen in only 11/50 after instruction. Levator co‐activation was associated with significantly lower bladder neck descent.ConclusionThe Valsalva maneuver is frequently accompanied by a pelvic floor muscle contraction. Levator co‐activation may be a substantial confounder, reducing pelvic organ descent. Without repetition and digital, auditory or visual biofeedback, women may not perform a correct Valsalva maneuver. Biofeedback markedly reduces the likelihood of levator co‐activation but does not abolish it completely. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Newborn screening in Latin America at the beginning of the 21st century
Authors: Borrajo G. J. C. 
Published: August 2007

SummaryNewborn screening (NBS) in Latin America took its first steps in the mid‐1970s. Nevertheless, many years elapsed before it achieved its integration within the public health care system and its systematic and continuous implementation under a programme structure. Latin American countries can be characterized not only by their great geographic, demographic, ethnic, economic and health system diversity, but also by their heterogeneity in NBS activities, which gives rise to variation in degree of organization: countries with optimal fulfilment (Cuba, Costa Rica, Chile, Uruguay); others rapidly expanding their coverage (Brazil, Mexico, Argentina); some others in a recent implementation phase (Colombia, Paraguay, Venezuela, Nicaragua, Peru); others with minimal, isolated and non‐organized activities (Guatemala, Dominican Republic, Bolivia, Panama, Ecuador); and finally others without any NBS activities at all (El Salvador, Honduras, Haiti). Despite this disparity, a sustained and significant growth in NBS activities has become evident during the last decade, highlighted by implementation of new programmes, increase in coverage, expansion of NBS panels, increasing involvement of governmental and public health authorities, and integration of NBS teams through scientific societies and External Quality Assurance Schemes. Currently, congenital hypothyroidism (CH) is the most widely screened disease, followed by phenylketonuria, with organized NBS programmes for CH in 14 countries. Other diseases usually included in NBS programmes are screened in a lower rate. Every year, around 11.2 million infants are born in Latin America. During 2005, 49.3% of newborns were screened for CH, indicating that around 5.7 million newborns still did not have access to the benefits of NBS.
Distress and Family Functioning in Oncogenetic Counselling for Hereditary and Familial Breast and/or Ovarian Cancers
Authors: Condello C. , Gesuita R. , Pensabene M. , Spagnoletti I. , Capuano I. , Baldi C. , Carle F. , Contegiacomo A. 
Published: August 2007

AbstractWe conducted a psychological assessment during oncogenetic counseling for hereditary breast/ovarian cancer. Anxiety and depression were assessed with the HAD scale, and family functioning and satisfaction with FACES III. HAD was administered at baseline (t1), at risk communication (t2), at genetic test result communication, or at first surveillance in not tested subjects (t3); FACES III was administered at baseline only. We analysed a total of 185 questionnaires administered to the 37 subjects studied. Although not pathological, distress was significantly higher at t2 and t3 (p = 0.027 and p = 0.039, respectively). Health and marital status were significantly associated with distress. In a disease‐free condition, anxiety was higher (p = 0.027) at t2, and for single status, depression increased from t1 to t2 (p = 0.026). Families were perceived to be well functioning, and subjects were satisfied with their families. The data collected in this analysis could help to improve the quality of oncogenetic counselling in clinical practice.