bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacological characterization of cis‐nitromethylene neonicotinoids in relation to imidacloprid binding sites in the brown planthopper, Nilaparvata lugens
Authors: Xu X. , Bao H. , Shao X. , Zhang Y. , Yao X. , Liu Z. , Li Z. 
Published: October 2009

AbstractNeonicotinoid insecticides, such as imidacloprid, are selective agonists of the insect nicotinic acetylcholine receptors (nAChRs) and extensively used in areas of crop protection and animal health to control a variety of insect pest species. Here we describe that two cis‐nitromethylene neonicotinoids (IPPA152002 and IPPA152004), recently synthesized in our laboratory, discriminated between the high and low affinity imidacloprid binding sites in the brown planthopper, Nilaparvata lugens, a major insect pest of rice crops in many parts of Asia. [3H]imidacloprid has two binding sites with different affinities (Kd value of 0.0035 ± 0.0006 nM for the high‐affinity site and 1.47 ± 0.22 nM for the low‐affinity site). Although the cis‐nitromethylene neonicotinoids showed low displacement ability (Ki values of 0.15 ± 0.03 µM and 0.42 ± 0.07 µM for IPPA152002 and IPPA152004, respectively) against [3H]imidacloprid binding, low concentrations (0.01 µM) of IPPA152002 completely inhibited [3H]imidacloprid binding at its high‐affinity site. In Xenopus oocytes co‐injected with cRNA encoding Nlα1 and rat β2 subunits, obvious inward currents were detected in response to applications of IPPA152002 and IPPA152004, although the agonist potency is reduced to that of imidacloprid. The previously identified Y151S mutation in Nlα1 showed significant effects on the agonist potency of IPPA152002 and IPPA152004, such as a 75.8% and 70.6% reduction in Imax, and a 2.4‐ and 2.1‐fold increase in EC50. This data clearly shows that the two newly described cis‐nitromethylene neonicotinoids act on insect nAChRs and like imidacloprid, discriminated between high and low affinity binding sites in N. lugens native nAChRs. These compounds may be useful tools to further elucidate the pharmacology and nature of neonicotinoid binding sites.
Factors affecting the permeability of transportation and riparian corridors to the movements of songbirds in an urban landscape
Authors: Tremblay Marie A. , St. Clair Colleen C. 
Published: October 2009

Summary 1. Linear features associated with transportation and riparian corridors are known to inhibit the mobility of birds and other wildlife, yet the factors contributing to their barrier effects are poorly understood. The diversity of roads in urban landscapes provides an opportunity for elucidating the relative importance of factors such as noise, traffic volume, gap width and adjacent vegetation on animal movement. 2. Using an avian mobbing call as a lure, we tested the willingness of forest songbirds to cross four types of linear features in the urban landscape of Calgary, Alberta, Canada: (1) roads of varying widths and traffic volumes, (2) conventional railways and light transit lines, (3) transportation bridges across riparian corridors, and (4) rivers. 3. Using mixed effects logistic regression, we found that the size of the gap in vegetation was the most important determinant of movement (P < 0·001). As the gap in vegetation exceeded 30 m, the likelihood of movement decreased dramatically and by 45 m, birds were only half as likely to move across gaps as they were to move an equivalent distance in continuous tree cover. Traffic volume also had a significant dampening effect on movement (odds ratio = 0·952 per 1000 vehicle per day increase; P < 0·001) and generally explained more variation in the data than noise levels. 4. Railroads proved to be the most permeable of the features we tested, probably owing to their relatively narrow width, which never exceeded 30 m. Surprisingly, rivers were less permeable than the anthropogenic linear features we tested, with a significant barrier effect evident even at widths <50 m. 5. The birds in our study showed a marked preference for flying over, rather than under, transportation bridges, particularly when adjacent vegetation was available. 6.
Synthesis and applications. Our results suggest that linear features, both anthropogenic and natural, can significantly impede the movements of forest songbirds and that managing adjacent vegetation is a potentially effective way to mitigate these barrier effects in cities and other fragmented landscapes.
Wiki‐supported learning and knowledge building: effects of incongruity between knowledge and information
Authors: Moskaliuk J. , Kimmerle J. , Cress U. 
Published: October 2009

AbstractThis study describes the empirical test of a theoretical model of knowledge building with wikis that was recently introduced by Cress and Kimmerle. The underlying assumption of this model is that both learning (as an internal, individual process) and knowledge building (as the creation of public knowledge) are based on the interplay between an individual's knowledge and the information available in the wiki. Incongruity between individual knowledge and the information contained in the wiki will lead to learning (through the acquisition of factual and conceptual knowledge) and to knowledge building (through assimilation and accommodation). In three conditions, the experiment provided the participants with different levels of incongruity between their individual knowledge and information in the wiki by varying the amount of information that was contained in the wiki, while the amount of information that the participants possessed was kept constant. As predicted, the results confirmed that a medium level of incongruity between an individual's knowledge and the information that a wiki contains will best support learning. Moreover, a medium level of incongruity leads to more accommodative knowledge building despite the fact that high and medium levels of incongruity will result in similar amounts of assimilative knowledge building. The implications of these findings were discussed in the concluding remarks.
Neutron scattering studies of  BiFeO3 multiferroics: a review for microscopists
Authors: SOSNOWSKA I.M. 
Published: October 2009

SummaryApplication of the neutron scattering technique in the study of crystal and magnetic properties of multiferroic BiFeO3 is presented. The crucial role of the neutron scattering technique, complementary to X‐ray diffraction method and transmission electron microscopy, is shown. Especially the ultra high‐resolution time‐of‐flight (TOF) neutron diffraction technique used by Sosnowska et al. to detect the magnetic cycloid ordering and its role in studies of physical properties of BiFeO3 and its alloys are reviewed. The first inelastic neutron scattering patterns of magnetic excitations in BiFeO3 are also presented. Applications of different microscopy techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), field emission TEM and SEM (FESEM and FETEM), magnetic force microscope (MFM) and polarization force microscopy (PFM) bring insight on the fundamental problem of ferroelectricity and confirm the potential of BiFeO3 multiferroic material for nanoscale devices.
Microstructure analysis of Nd‐Fe‐B sintered magnets improved by Tb‐metal vapour sorption
Authors: WATANABE N. , UMEMOTO H. , ISHIMARU M. , ITAKURA M. , NISHIDA M. , MACHIDA K. 
Published: October 2009

SummaryBehaviours of constituent elements in the Nd‐Fe‐B sintered magnets improved by Tb‐metal vapour sorption have been investigated by using an analytical transmission microscopy. It was found that a triple junction of the grain boundaries consists of fine Nd‐O crystalline and amorphous phase. The energy dispersive X‐ray spectroscopy (EDS) analysis showed that the amorphous phase mainly consists of Co, Nd and Tb. The Tb‐treatment causes the formation of the amorphous Co‐Nd(Tb) wetting‐layer phase which wraps each Nd2Fe14B grain. The results suggest that the wrapped structure prevents the nucleation of magnetic reversed domains and then improves significantly the coercivity of the magnet.
Fine structures of wing scales in Sasakia charonda butterflies as photonic crystals
Authors: MATĚJKOVÁ‐PLSKOVA J. , SHIOJIRI S. , SHIOJIRI M. 
Published: October 2009

SummaryWe investigate the microstructure of scales in the wings of male Sasakia charonda charonda butterflies by scanning electron microscopy with the aid of optical microscopy. Six types of scales are identified: B1, W1 and R1 in brown background yellow spots and red spots, respectively; B2 in iridescent purple‐blue and W2 in white pearl, both of which characterize the male and B3 in the wing edges. The B1, W1 and R1 scales are almost the same in structure and the B2 and W2 scales are almost the same. The difference among the B, W and R scales is in species and content of pigment. The B1, W1 and R1 scales have only two layers of cuticle lapped on the ridges. In contrast with them, the B2 and W2 scales have seven multilayers of cuticle piled on the ridge. The multiple interference of light that occurs among these cuticle layers, spaced with air layers, generates the significant iridescence of the B2 and W2 scales. Thus, the characteristic purple‐blue of the male wings is ascribed to the combination of the structural and chemical colouration in the B2 scales with melanin. The photonic crystals of these scales may be applicable to fine light manipulators such as reflection elements in laser diodes. B3 has many holes between the ridges and no multilayers of cuticle on the ridges. These structures may play any role in aerodynamically easy flight and/or in drainage of wet wings.
Electron microscopy study of L10‐FePtCu nanoparticles synthesized at 613K
Authors: HIROTSU Y. , RYU H.W. , SATO K. , ISHIMARU M. 
Published: October 2009

SummaryFinely dispersed hard magnetic L1o‐FePtCu nanoparticles with 〈100〉 orientation were directly synthesized by RF‐sputtering on NaCl substrate at a temperature of 613 K. The maximum coercivity of the particles was 1.4 kOe (at RT). Degrees of atomic long‐range order (LRO) for the L1o‐FePtCu nanoparticles with different sizes were obtained using nanobeam electron diffraction technique. The decrease of LRO parameter became remarkable when the size became below 8 nm. The coercivity value also decreased with decreasing the particle size. The relation between the LRO parameter decrease and the coercivity decrease with particle size was discussed.
Microstructure and properties of hot compacted powders of aluminium alloys
Authors: LITYŃSKA‐DOBRZYŃSKA L. , DUTKIEWICZ J. , MAZIARZ W. , KANCIRUK A. 
Published: October 2009

SummaryAtomized 6061 aluminium alloy powders with and without the addition of 2 wt% Zr were milled for 80 h in a planetary ball mill and hot pressed in vacuum. The milled powders showed microhardness of about 170 HV, which increased after hot pressing up to 260 HV and up to 280 HV for powders without and with the Zr additions, respectively. Compression tests showed the high yield stress of 300 MPa obtained for the hot‐pressed sample produced from the initial powders compared with ultimate compression strength of above 800 MPa for that of the milled sample and slightly higher for that with Zr additions. The effect of hot pressing on the structure of powders was investigated using a conventional analytical and high‐resolution electron microscopy and high angle annular dark‐field scanning transmission electron microscopy combined with energy dispersive X‐ray microanalysis. The samples of initial powders hot pressed in vacuum showed a cell structure with particles of the Mg2Si and AlFeSi phases in intercell areas. In the milled and hot‐pressed sample, the homogeneous structure of small grains of size below 200 nm was observed. The AlFeSi and Mg2Si particles with size 20–100 nm were uniformly distributed as well as the Zr rich particles in the Zr containing alloy. The Zr‐rich particles containing up to 80 at% Zr were identified as a metastable fcc cubic phase with lattice parameter a= 0.48 nm.
TEM determination of directions of (Ga,Mn)As nanowires grown by MBE on GaAs(001) substrates
Authors: DŁUŻEWSKI P. , SADOWSKI J. , KRET S. , DĄBROWSKI J. , SOBCZAK K. 
Published: October 2009

SummaryThe structure of GaMnAs nanowires (NW) with nominal Mn concentration of up to 7 at% was investigated by transmission electron microscopy. The (Ga,Mn)As NW were grown on epiready GaAs(001) n‐type wafers by molecular beam epitaxy. The crystal structure of the NW was determined to be zinc‐blende. NW with Mn concentrations lower than 5 at% grow along the 〈111〉 direction. NW with higher Mn concentrations grow along the 〈110〉 direction and reveal a branching structure. The main nanowire and branches grow along the 〈110〉 directions belonging to only one {111} plane.
HRTEM studies of NiNbZr + Ag amorphous‐nanocrystalline composites
Authors: DUTKIEWICZ J. , LITYŃSKA‐DOBRZYŃSKA L. , KOVACOVA A. , ROGAL Ł. , MAZIARZ W. 
Published: October 2009

SummaryAmorphous powder of composition corresponding to Ni60Ti20Zr20 (in at%) was obtained by ball milling in a high‐energy mills starting from pure elements. Formation of the amorphous structure was observed already after 20 h of milling, although complete amorphization occurred after 40 h. The microhardness of powders increased from about 30 HV for pure elements to above 400 HV (1290 MPa) after 40 h of milling. Transmission electron microscopy (TEM) allowed to identify nanocrystalline inclusions of intermetallic phases of size 2–10 nm. Uniaxial hot pressing was performed in vacuum at temperature below the crystallization Tx it is 510°C and pressure of 600 MPa, Mixed amorphous powders and nanocrystalline silver powders were used to form a composite, in which microhardness was near 970 MPa HV and 400 HV for the amorphous phase and nanocrystalline silver, respectively. The compression strength of the composite containing 20 wt% of nanocrystalline Ag powder was equal to 600 MPa and plastic strain was 2%. Microstructure studies showed low porosity of composites of less than 1%, uniform distribution of the silver phase and a transition zone between both components, about 150 nm thick, where diffusion of nickel, niobium and zirconium into silver was observed. High‐resolution TEM allowed identifying the structure of nanocrystalline inclusions in the amorphous matrix after hot pressing as either Ni3Zr or Ni17Nb3. The identification was performed basing on measurements of angles and interatomic distances using inverse Fourier transformed images with enhanced contrast using Digital Micrograph computer program.
New approach to cathodoluminescence studies in application to InGaN/GaN laser diode degradation
Authors: PŁUSKA M. , CZERWINSKI A. , RATAJCZAK J. , KĄTCKI J. , MARONA L. , CZERNECKI R. , LESZCZYŃSKI M. , PERLIN P. 
Published: October 2009

SummaryCathodoluminescence (CL) studies are widely applied in semi‐conductor science and technology. However, for structures with a p‐n junction the CL spatial distribution can be strongly affected by internal current flows of the electron beam induced current generated within the structure. This influence is the investigated in application to CL studies of degradation in aged laser diodes with InGaN multiquantum wells.
Microstructure of ball milled and compacted Co–Ni–Al alloys from the β range
Authors: MAZIARZ W. , DUTKIEWICZ J. , ROGAL Ł. , GRZONKA J. , CESARI E. 
Published: October 2009

SummaryTwo powder alloys from the β phase region of compositions Co28.5Ni36.5Al35 and Co35Ni30Al35 were ball milled for 80 h in a high energy ball mill. The formation of amorphous structure was observed after 40 h of milling and further milling did not change their structure. The analytical and high‐resolution transmission electron microscopy (TEM, HREM) examination of powder structure showed that nanoparticles of  L10 phase of size of about 5 nm were present within the amorphous matrix. The vacuum hot pressing of the milled powders under pressure of 400 MPa at 700°C for 12 min resulted in the formation of compacts with density of about 70% of the theoretical one. The additional heat treatment at 1300°C for 6 h followed by water quenching, led to significant improvement of density and induced the martensitic transformation manifested by a broad heat effect. The characteristic temperatures of the transformation were determined using DSC measurements, which revealed only small differences within the examined alloys compositions. TEM structure studies of heat‐treated alloys allowed to identify the structure of an ordered β (B2) phase and L10 martrensite.
Rapid quantification of the effects of blotting for correlation of light and cryo‐light microscopy images
Authors: LEPPER S. , MERKEL M. , SARTORI A. , CYRKLAFF M. , FRISCHKNECHT F. 
Published: October 2009

SummaryRecent technical developments allowed the accurate correlation of fluorescently labelled organelles in living cells to cryo‐electron micrographs. We aimed at expanding this approach to Plasmodium berghei sporozoites, the motile forms of a rodent malaria parasite, which can be imaged by cryo‐electron tomography in toto without the need for sectioning. Sporozoites are crescent shaped eukaryotic cells that move on flat supports including EM grids in a circular, unidirectional manner. While sporozoites can be visualized with fluorescent light and cryo‐light microscopy prior to tomography, few motile sporozoites remained on the grid after blotting excess liquid impairing a complete correlation from light microscopy to cryo‐electron tomography. Comparison with cells showing different adhesion strengths demonstrated that the ratio of cells remaining on the grid can be rapidly determined, but that the integrity of the cells has to be carefully monitored as the blotting applies high physical stress to the cells. We demonstrate a quick technique to assess not only feasibility of direct correlation without fixation but also the damage caused by blotting.
Micro‐computed X‐ray tomography: a new non‐destructive method of assessing sectional, fly‐through and 3D imaging of a soft‐bodied marine worm
Authors: DINLEY J. , HAWKINS L. , PATERSON G. , BALL A.D. , SINCLAIR I. , SINNETT‐JONES P. , LANHAM S. 
Published: October 2009

SummaryThe detailed examination of the internal and functional anatomy of soft‐bodied marine worms has, until now, only been possible using the time consuming and destructive techniques of dissection, histology and electron microscopy. This is the first description of soft body morphology in polychaetes (Nephtys hombergii) derived by means of a bench‐top X‐ray micro‐CT scanner. The data are augmented, for comparison, by dissections, microscopy and scanning electron microscopy of the same species to show how this non‐destructive technique can rapidly and reliably produce high‐quality morphological data. It can also be applied to rare or unique invertebrate soft tissue material from museum collections and also to large‐scale invertebrate comparative anatomical studies possibly leading to greater evolutionary and taxonomic understanding. High‐definition images were obtained without the use of special tissue enhancing stains or radio‐opaque fluids and it is believed that this is the first time the technique has been successfully applied to this group of invertebrates. Extrapolation of the sectional imaging of regions of the gut and the production of three‐dimensional rotating and ‘fly‐through’ imaging can assist in assessment of aspects of functional anatomy.
Quality control protocol for in vitro micro‐computed tomography
Authors: STOICO R. , TASSANI S. , PERILLI E. , BARUFFALDI F. , VICECONTI M. 
Published: October 2009

SummaryThe aim of this work was to present and discuss a quality control protocol for in vitro micro‐computed tomography (microCT), based on the adaptation of the quality control protocols for medical computed tomography. The importance of establishing a quality control protocol is related to the opportunity to identify problems on time comparing the microCT images acquired in different time points, and in this way to verify the performance of the device. The proposed quality control protocol was applied for a long‐time monitoring period to verify the stability of the micro‐tomographic system over time. The protocol proposed in this study was applied to the histomorphometric characterization of bone tissue, but it can be used on a wide range of in vitro microCT applications. Noise and uniformity tests, taken and adapted to micro‐tomographic system by medical standard guidelines of quality control, were performed by the use of a water phantom. An accuracy test was designed and performed by the use of a morphometric calibrated phantom. All these tests were performed during a long‐time monitoring period to control the stability of the system. Specific control charts and monitoring parameters for each test were used to represent the monthly measures collected during 20 months and an out of control condition was defined. The reference values (baseline), calculated to control the stability of micro‐tomographic system over time, were calculated during acceptance/status test. During the period, no out of control conditions in noise, uniformity and accuracy tests were recorded. However, a changing condition was found in noise test, as showed by using statistical C (P < 0.01) and Kruskal–Wallis (P < 0.05) tests. In particular, a Wilcoxon rank sum test with Bonferroni correction (P < 0.0125) was applied in noise test to investigate which of the comparisons among first five acquisitions of year 2004 (group B.L.) and each group was significant (P < 0.0125). The noise showed a slight but significant increase over the years compared to baseline value; however, no out of control conditions were recorded. Nonetheless, a maintenance service to control the performance of mechanical components of microCT was required and performed.
Measurement of potential distribution function on object surface by using an electron microscope in the mirror operation mode
Authors: NEPIJKO S.A. , SCHÖNHENSE G. 
Published: October 2009

SummaryThe quantitative theory of image contrast in an electron microscope in the mirror operation mode is given in this paper. This theory permits us to calculate the potential distribution on the object surface from the current density distribution on the microscope screen. The potential distribution results in image formation on the screen. Local electric fields existing on the object surface lead to a perturbation of electron trajectories above the object and to a redistribution of the current density on the screen, causing image contrast. Using the quantitative correlation between these fields and the function of current density distribution on the screen, it is possible to calculate the magnitude of these microfields as well. As illustration, a measured potential distribution on an object surface with spiral structures of adsorbates was analysed. These structures are formed during reaction of CO oxidation on Pt(110). The value of the measured contact potential difference comprised a few hundredths of volt.