bluuebunny/crossref_metadata_2025 huggingface dataset:
Global cooling and densification of the plasma sheet during an extended period of purely northward IMF on October 22–24, 2003
Authors: Øieroset M. , Raeder J. , Phan T. D. , Wing S. , McFadden J. P. , Li W. , Fujimoto M. , Rème H. , Balogh A.
Published: April 2005

The October 22–24, 2003 interplanetary magnetic cloud was characterized by an exceptionally long interval (∼32 hours) of nearly purely northward interplanetary magnetic field (IMF). Following the northward IMF turning Cluster observed a gradual transition to a cold (<1 keV) and dense (∼1–2 cm−3) plasma sheet (CDPS). Cluster observed CDPS continuously for the following ∼30 hours while passing through the neutral sheet from the northern to the southern hemisphere. DMSP observations mapped to the equatorial plasma sheet reveal that the CDPS extended to all nightside local times. The FAST satellite observed reversed ion dispersion signatures in the cusp indicative of poleward‐of‐cusp reconnection, and nearly no polar cap. The CDPS observations show good agreement with a global MHD simulation where the CDPS is formed by poleward‐of‐cusp reconnection capturing magnetosheath plasma and convecting it to the tail. The process shrinks the size of the lobes (and therefore the polar cap) significantly, as observed.
Plasma sheet formation during long period of northward IMF
Authors: Li Wenhui , Raeder Joachim , Dorelli John , Øieroset Marit , Phan Tai D.
Published: April 2005

We have studied the entry paths of solar wind plasma into the magnetosphere during an extended period of northward IMF using an OpenGGCM MHD simulation of the cold dense plasma sheet (CDPS) event observed on October 23, 2003 by the Cluster spacecraft. We find that high‐latitude reconnection occurs tailward of both cusps between the IMF and geomagnetic field. The newly created closed magnetic flux tubes capture magnetosheath plasma, and subsequently sink and shrink into the magnetosphere, while convecting tailward. The plasma that enters near the reconnection site is driven sunward and toward the low latitude region initially; it then drifts to the flanks. The captured plasma is characterized by small flow velocity, and it is moderately heated in the reconnection region. In the present case study we find the cold plasma enters the plasma sheet in the near Earth tail where it is observed by Cluster.
Evidence for variability of atmospheric hydroxyl radicals over the past quarter century
Authors: Prinn R. G. , Huang J. , Weiss R. F. , Cunnold D. M. , Fraser P. J. , Simmonds P. G. , McCulloch A. , Harth C. , Reimann S. , Salameh P. , O'Doherty S. , Wang R. H. J. , Porter L. W. , Miller B. R. , Krummel P. B.
Published: April 2005

The hydroxyl free radical (OH) is the major oxidizing chemical in the atmosphere, destroying about 3.7 petagrams (Pg) of trace gases each year, including many gases involved in ozone depletion, the greenhouse effect and urban air pollution. Measurements of 1,1,1‐trichloroethane (methyl chloroform, CH3CCl3), which reacts with OH, provide the most accurate method currently utilized for determining the global behavior of OH. We report that CH3CCl3 levels rose steadily from 1978 to reach a maximum in 1992 and have since decreased rapidly to levels in 2004 about 30% of the levels when measurements began in 1978. Analysis of these observations shows that global average OH levels had a small maximum around 1989 and a larger minimum around 1998, with OH concentrations in 2003 being comparable to those in 1979. This post‐1998 recovery of OH reported here contrasts with the situation 4 years ago when reported OH was decreasing. The 1997–1999 OH minimum coincides with, and is likely caused by, major global wildfires and an intense El Nino event at this time.
Adaptive mesh seismic tomography based on tetrahedral and Voronoi diagrams: Application to Parkfield, California
Authors: Zhang Haijiang , Thurber Clifford
Published: April 2005

We have developed an adaptive mesh seismic tomography method based on tetrahedral and Voronoi diagrams to automatically match the inversion mesh to the data distribution. Two different irregular mesh interpolation methods, linear and natural neighbor, are evaluated. A synthetic test shows that the adaptive mesh seismic tomography method recovers the true synthetic model well in both the linear and natural neighbor interpolation cases. Use of more accurate differential data is helpful in removing artifacts in the model that result from the noisier absolute data. Application of the adaptive mesh scheme to Parkfield, California, results in much more uniform sampling of the model (as measured by the derivative weight sum) on the optimized irregular inversion mesh compared to a regular grid. The across‐strike cross sections resulting from using either just the absolute data or both the absolute and differential data show a clear velocity contrast at the San Andreas fault in the linear and natural neighbor interpolation cases. The velocity model obtained using natural neighbor interpolation is smoother than that from linear interpolation. Including the differential data in the inversion yields more clustered event locations and removes a velocity reversal to the southwest of the fault, which is likely caused by noise in the absolute data.
Intramolecular isotope distribution in heavy ozone (16O18O16O and 16O16O18O)
Authors: Janssen C.
Published: April 2005

The ratio of asymmetric vs. symmetric molecules of heavy ozone, r50 = [16O16O18O]/[16O18O16O], or similarly r49 for 17O‐containing ozone, is an essential feature of the unusual oxygen isotope effect in ozone formation. Whereas information on r49 is sparse and of limited accuracy, precision in laboratory measurements of r50 has recently been improved. The two most recent experiments, however, disagree on whether there is a preference for the formation of asymmetric over symmetric molecules or not (r50 > 2 versus r50 = 2). To throw light on this discrepancy, the temperature dependence of r50 has been derived from a reanalysis of existing measurements: r50 is found to decrease from 2.13 at 360 K to about 2.00 at 170 K. Kinetic model calculations show that the discrepancy between the two measurements disappears when temperature conditions for ozone formation are accounted for. The reanalysis confirms that the isotope enrichment in atmospheric 16O218O predominantly but not exclusively resides in the asymmetric molecule, with the preference for asymmetric molecules becoming smaller at low‐temperature conditions. The enrichment of 16O16O18O which likely characterizes the source strength of ozone to transfer heavy oxygen (18O) into other atmospheric molecules is quantified as a function of temperature and in relation to the overall enrichment of heavy ozone. This information can now be used in atmospheric models that simulate isotope transfer effects.
Spherical and spheroidal model particles as an error source in aerosol climate forcing and radiance computations: A case study for feldspar aerosols
Authors: Kahnert M. , Nousiainen T. , Veihelmann B.
Published: April 2005

A case study for feldspar aerosols is conducted to assess the errors introduced by simple model particles in radiance and flux simulations. The spectral radiance field and net flux are computed for a realistic phase function of feldspar aerosols measured in the laboratory at 633 nm. Results are compared to computations with spherical and spheroidal model particles. It is found that the use of spherical model particles introduces large spectral radiance errors at top of atmosphere (TOA) between −6 and 31%. Using a new shape parameterization of spheroids reduces the error range to −1 to 6%. Spherical model particles yield an absolute TOA spectral net flux error of −6.1 mW m−2 nm−1. An equiprobable shape distribution of spheroids results in only minor improvements, but the new shape parameterization yields an error of only −0.8 mW m−2 nm−1. A variation of the refractive index m reveals that the resulting changes in the TOA spectral net flux are slightly smaller than the error caused by assuming the particles to be spherical. However, the uncertainty of m is commonly considered the major error source in aerosol radiative forcing simulations, whereas the use of spherical model particles is often not seriously questioned. This study implies that this notion needs to be reconsidered. Should the relative spectral net flux errors be representative for the entire spectrum, then the use of spherical model particles may be among the major error sources in broadband flux simulations. The new spheroidal shape parameterization can, however, substantially improve the results.
Lunar optical maturity investigations: A possible recent impact crater and a magnetic anomaly
Authors: Blewett David T. , Hawke B. Ray , Lucey Paul G.
Published: April 2005

We have used maps of the OMAT optical maturity parameter, along with other Clementine UV‐Vis image products, to study two interesting lunar features related to albedo and optical maturity. Examination of the region of a small crater whose formation has been suggested to be a candidate for the flash photographed in 1953 by Stuart demonstrates that the candidate crater is not unusually fresh compared to other small craters in the vicinity. Therefore it is unlikely that the formation of this impact crater generated the observed flash. An area of unusually high albedo in the Descartes highlands is also known to be a magnetic anomaly. It has been proposed that the presence of the magnetic anomaly has prevented the solar wind from reaching the surface for billions of years and therefore that the area has not undergone normal space weathering and preserved a high albedo. The high albedo is caused only by maturity differences with the surroundings, not by an exotic composition. The fact that the albedo anomaly has not darkened or reddened to the extent expected may be the result of the surface texture as revealed in 3.8‐cm radar images. We suggest that the fresh appearance is largely caused by overlapping ejecta from two nearby craters and continual exposure of immature material by the erosion of 1‐ to 10‐cm‐sized fragments within the deposit. The magnetic shielding mechanism, if operative, probably plays only a minor role in producing the Descartes albedo anomaly.
Functional, Perfusion and Diffusion MRI of acute Focal Ischemic Brain Injury
Authors: Shen Qiang , Ren Hongxia , Cheng Haiying , Fisher Marc , Duong Timothy Q
Published: April 2005

Combined functional, perfusion and diffusion magnetic resonance imaging (MRI) with a temporal resolution of 30 mins was performed on permanent and transient focal ischemic brain injury in rats during the acute phase. The apparent diffusion coefficient (ADC), baseline cerebral blood flow (CBF), and functional MRI (fMRI) blood-oxygen-level-dependent (BOLD), CBF, and CMRO2 responses associated with CO2 challenge and forepaw stimulation were measured. An automated cluster analysis of ADC and CBF data was used to track the spatial and temporal progression of different tissue types (e.g., normal, ‘at risk,’ and ischemic core) on a pixel-by-pixel basis. With permanent ischemia ( n = 11), forepaw stimulation fMRI response in the primary somatosensory cortices was lost, although vascular coupling (CO2 response) was intact in some animals. Control experiments in which the right common carotid artery was ligated without causing a stroke ( n = 8) showed that the delayed transit time had negligible effect on the fMRI responses in the primary somatosensory cortices. With temporary (15-mins, n = 8) ischemia, transient CBF and/or ADC declines were observed after reperfusion. However, no T2 or TTC lesions were observed at 24 h except in two animals, which showed very small subcortical lesions. Vascular coupling and forepaw fMRI response also remained intact. Finally, comparison of the relative and absolute fMRI signal changes suggest caution when interpreting percent changes in disease states in which the baseline signals are physiologically altered; quantitative CBF fMRI are more appropriate measures. This approach provides valuable information regarding ischemic tissue viability, vascular coupling, and functional integrity associated with ischemic injury and could have potential clinical applications.
Comparative analysis of the pathogenic mechanisms associated with the G8363A and A8296G mutations in the mitochondrial tRNALys gene
Authors: BORNSTEIN Belén , MAS José Antonio , PATRONO Clarice , FERNÁNDEZ-MORENO Miguel Angel , GONZÁLEZ-VIOQUE Emiliano , CAMPOS Yolanda , CARROZZO Rosalba , MARTÍN Miguel Angel , HOYO Pilar del , SANTORELLI Filippo M. , ARENAS Joaquín , GARESSE Rafael
Published: April 2005

Two mutations (G8363A and A8296G) in the mtDNA (mitochondrial DNA) tRNALys gene have been associated with severe mitochondrial diseases in a number of reports. Their functional significance, however, remains unknown. We have already shown that homoplasmic cybrids harbouring the A8296G mutation display normal oxidative phosphorylation, although the possibility of a subtle change in mitochondrial respiratory capacity remains an open issue. We have now investigated the pathogenic mechanism of another mutation in the tRNALys gene (G8363A) by repopulating an mtDNA-less human osteosarcoma cell line with mitochondria harbouring either this genetic variant alone or an unusual combination of the two mutations (A8296G+G8363A). Cybrids homoplasmic for the single G8363A or the A8296G+G8363A mutations have defective respiratory-chain enzyme activities and low oxygen consumption, indicating a severe impairment of the oxidative phosphorylation system. Generation of G8363A cybrids within a wild-type or the A8296G mtDNA genetic backgrounds resulted in an important alteration in the conformation of the tRNALys, not affecting tRNA steady-state levels. Moreover, mutant cybrids have an important decrease in the proportion of amino-acylated tRNALys and, consequently, mitochondrial protein synthesis is greatly decreased. Our results demonstrate that the pathogenicity of the G8363A mutation is due to a change in the conformation of the tRNA that severely impairs aminoacylation in the absence of changes in tRNA stability. The only effect detected in the A8296G mutation is a moderate decrease in the aminoacylation capacity, which does not affect mitochondrial protein biosynthesis.
Probing a putative dantrolene-binding site on the cardiac ryanodine receptor
Authors: PAUL-PLETZER Kalanethee , YAMAMOTO Takeshi , IKEMOTO Noriaki , JIMENEZ Leslie S. , MORIMOTO Hiromi , WILLIAMS Philip G. , MA Jianjie , PARNESS Jerome
Published: April 2005

Dantrolene is an inhibitor of intracellular Ca2+ release from skeletal muscle SR (sarcoplasmic reticulum). Direct photoaffinity labelling experiments using [3H]azidodantrolene and synthetic domain peptides have demonstrated that this drug targets amino acids 590–609 [termed DP1 (domain peptide 1)] of RyR1 (ryanodine receptor 1), the skeletal muscle RyR isoform. Although the identical sequence exists in the cardiac isoform, RyR2 (residues 601–620), specific labelling of RyR2 by dantrolene has not been demonstrated, even though some functional studies show protective effects of dantrolene on heart function. Here we test whether dantrolene-active domains exist within RyR2 and if so, whether this domain can be modulated. We show that elongated DP1 sequences from RyR1 (DP1-2s; residues 590–628) and RyR2 (DP1-2c; residues 601–639) can be specifically photolabelled by [3H]azidodantrolene. Monoclonal anti-RyR1 antibody, whose epitope is the DP1 region, can recognize RyR1 but not RyR2 in Western blot and immunoprecipitation assays, yet it recognizes both DP1-2c and DP1-2s. This suggests that although the RyR2 sequence has an intrinsic capacity to bind dantrolene in vitro, this site may be poorly accessible in the native channel protein. To examine whether it is possible to modulate this site, we measured binding of [3H]dantrolene to cardiac SR as a function of free Ca2+. We found that ≥10 mM EGTA increased [3H]dantrolene binding to RyR2 by ∼2-fold. The data suggest that the dantrolene-binding site on RyR2 is conformationally sensitive. This site may be a potential therapeutic target in cardiovascular diseases sensitive to dysfunctional intracellular Ca2+ release.
Epolactaene binds human Hsp60 Cys442 resulting in the inhibition of chaperone activity
Authors: NAGUMO Yoko , KAKEYA Hideaki , SHOJI Mitsuru , HAYASHI Yujiro , DOHMAE Naoshi , OSADA Hiroyuki
Published: April 2005

Epolactaene is a microbial metabolite isolated from Penicillium sp., from which we synthesized its derivative ETB (epolactaene tertiary butyl ester). In the present paper, we report on the identification of the binding proteins of epolactaene/ETB, and the results of our investigation into its inhibitory mechanism. Using biotin-labelled derivatives of epolactaene/ETB, human Hsp (heat-shock protein) 60 was identified as a binding protein of epolactaene/ETB in vitro as well as in situ. In addition, we found that Hsp60 pre-incubated with epolactaene/ETB lost its chaperone activity. The in vitro binding study showed that biotin-conjugated epolactaene/ETB covalently binds to Hsp60. In order to investigate the binding site, binding experiments with alanine mutants of Hsp60 cysteine residues were conducted. As a result, it was suggested that Cys442 is responsible for the covalent binding with biotin-conjugated epolactaene/ETB. Furthermore, the replacement of Hsp60 Cys442 with an alanine residue renders the chaperone activity resistant to ETB inhibition, while the alanine replacement of other cysteine residues do not. These results indicate that this cysteine residue is alkylated by ETB, leading to Hsp60 inactivation.
A proteolytic fragment of Mcl-1 exhibits nuclear localization and regulates cell growth by interaction with Cdk1
Authors: JAMIL Sarwat , SOBOUTI Rafat , HOJABRPOUR Payman , RAJ Meera , KAST Juergen , DURONIO Vincent
Published: April 2005

Mcl-1 (myeloid cell leukaemia-1) is a Bcl-2 family member with short-term pro-survival functions but whose other functions, demonstrated by embryonic lethality of knockout mice, do not involve apoptosis. In the present study, we show a cell-cycle-regulatory role of Mcl-1 involving a shortened form of the Mcl-1 polypeptide, primarily localized to the nucleus, which we call snMcl-1. snMcl-1 interacts with the cell-cycle-regulatory protein Cdk1 (cyclin-dependent kinase 1; also known as cdc2) in the nucleus, and Cdk1 bound to snMcl-1 was found to have a lower kinase activity. The interaction with Cdk1 occurs in the absence of its cyclin partners and is enhanced on treatment of cells with G2/M blocking agents, but not by G1/S blocking. The snMcl-1 polypeptide is present during S and G2 phases and is negligible in G1. Overexpression of human Mcl-1 in a murine myeloid progenitor cell line resulted in a lower rate of proliferation. Furthermore, Mcl-1-overexpressing cells had lower total Cdk1 kinase activity compared with parental cells, in both anti-Cdk1 and anti-cyclin B1 immunoprecipitates. The latter results suggest that binding to snMcl-1 alters the ability of Cdk1 to bind its conventional partner, cyclin B1. Given the important role of Cdk1 in progression through G2 and M phases, it is probable that the inhibition of Cdk1 activity accounts for the inhibitory effect of Mcl-1 on cell growth.
Probing conformational changes of human serum albumin due to unsaturated fatty acid binding by chemical cross-linking and mass spectrometry
Authors: HUANG Bill X. , DASS Chhabil , KIM Hee-Yong
Published: April 2005

Mass spectrometry with chemical cross-linking was used to probe the conformational changes of HSA (human serum albumin) in solution on interaction with monounsaturated OA (oleic acid) or polyunsaturated AA (arachidonic acid) or DHA (docosahexaenoic acid). Fatty acid-free or -bound HSA was modified with lysine-specific cross-linkers and digested with trypsin. Cross-linked peptides were analysed by nano-electrospray ionization MS to localize the sites of cross-linking. Our data indicated that a local conformational change involving movement of the side chains of Lys-402 of subdomain IIIA or Lys-541 of subdomain IIIB occurred upon binding of all three fatty acids. Our data also indicated that the side chains of Lys-205 (IIA) and Lys-466 (IIIA) moved closer towards each other upon binding AA or DHA, but not OA, suggesting that the conformations of HSA when bound to mono- and poly-unsaturated fatty acids are distinctively different. While these observations agreed with previous X-ray crystallographic studies, the distances between ε-amino groups of most cross-linked lysine pairs were shorter than the crystal structure predicted, possibly reflecting a discrepancy between the solution and crystal structures. This method can serve as a useful complement to X-ray crystallography, particularly in probing the structure of a protein in solution.
Generation and function of astroglial lipoproteins from Niemann–Pick type C1-deficient mice
Authors: KARTEN Barbara , HAYASHI Hideki , FRANCIS Gordon A. , CAMPENOT Robert B. , VANCE Dennis E. , VANCE Jean E.
Published: April 2005

NPC (Niemann–Pick type C) disease is a progressive neurological disorder characterized by defects in intracellular cholesterol trafficking, accumulation of cholesterol in the endosomal system and impaired cholesterol homoeostasis. Although these alterations appear to occur in all NPC1-deficient cell types, the consequences are most profound in the nervous system. Since glial cells are important mediators of brain cholesterol homoeostasis, we proposed that defective generation and/or function of lipoproteins released by glia might contribute to the neurological abnormalities associated with NPC disease. We found that, as in other cell types, Npc1−/− glia accumulate cholesterol intracellularly. We hypothesized that this sequestration of cholesterol in glia might restrict the availability of cholesterol for lipoprotein production. Cerebellar astroglia were cultured from a murine model of NPC disease to compare the lipoproteins generated by these cells and wild-type glia. The experiments demonstrate that the amount of cholesterol in glia-conditioned medium is not reduced by NPC1 deficiency. Similarly, cholesterol efflux to apo (apolipoprotein) A1 or glial expression of the transporter ATP-binding-cassette transporter A1 was not decreased by NPC1 deficiency. In addition, the ratio of apo E:cholesterol and the density distribution of lipoproteins in Npc1−/− and Npc1+/+ glia-conditioned medium are indistinguishable. Importantly, in a functional assay, apo E-containing lipoproteins generated by Npc1−/− and Npc1+/+ glia each stimulate axonal elongation of neurons by approx. 35%. On the basis of these observations, we speculate that the neuropathology characteristic of NPC disease can quite probably be ascribed to impaired processes within neurons in the brain rather than defective lipoprotein production by astroglia.
Lsb5p interacts with actin regulators Sla1p and Las17p, ubiquitin and Arf3p to couple actin dynamics to membrane trafficking processes
Authors: COSTA Rosaria , WARREN Derek T. , AYSCOUGH Kathryn R.
Published: April 2005

The importance of coupling the process of endocytosis to factors that regulate actin dynamics has been clearly demonstrated in yeast, and many proteins involved in these mechanisms have been identified. Sla1p is a well-characterized yeast protein that binds both to activators of actin dynamics, Las17p and Pan1p, and to cargo proteins, such as the pheromone receptor Ste2p. Previously, we reported that the Lsb5 protein plays a role in endocytosis in yeast and that it localizes to the plasma membrane. Lsb5p has a similar structure to the GGA [Golgi-localized, γ-ear-containing, Arf (ADP-ribosylation factor)-binding] family of proteins with an N-terminal VHS [Vps27p (vacuolar protein sorting protein 27), Hrs, Stam] domain and a GAT (GGA and Tom1) domain. It does not, however, contain either a γ-adaptin ear or a clathrin-binding motif. In the present study, we have further defined its interaction site with both Sla1p and with Las17p, two regulators of actin dynamics. The site of interaction with Sla1p involves the Sla1 HD1 (homology domain 1), which also was shown previously to interact with the pheromone receptor Ste2p. We also demonstrate hitherto unknown interactions between Lsb5p and the active form of the yeast Arf3 protein, and with ubiquitin. Finally, we demonstrate a requirement for Arf3p expression in order to localize Lsb5p to the correct cortical site in cells. Taken together, our data provide further evidence for the role of Lsb5p in membrane-trafficking events at the plasma membrane and also demonstrate for the first time an interaction of Arf3 with the endocytic machinery in yeast.
Experimental measurement of the induced dipole moment of an isolated molecule in its ground and electronically excited states: Indole and indole–H2O
Authors: Kang Cheolhwa , Korter Timothy M. , Pratt David W.
Published: April 2005

Reported here are measurements of the magnitude and orientation of the induced dipole moment that is produced when an indole molecule in its ground S0 and electronically excited S1 states is polarized by the attachment of a hydrogen bonded water molecule in the gas phase complex indole–H2O. For the complex, we find the permanent dipole moment values μIW(S0)=4.4D and μIW(S1)=4.0D, values that are substantially different from calculated values based on vector sums of the dipole moments of the component parts. From this result, we derive the induced dipole moment values μI*(S0)=0.7D and μI*(S1)=0.5D. The orientation of the induced moment also is significantly different in the two electronic states. These results are quantitatively reproduced by a purely electrostatic calculation based on ab initio values of multipole moments.
Molecular dynamics integration and molecular vibrational theory. III. The infrared spectrum of water
Authors: Praprotnik Matej , Janežič Dušanka
Published: April 2005

The new symplectic molecular dynamics (MD) integrators presented in the first paper of this series were applied to perform MD simulations of water. The physical properties of a system of flexible TIP3P water molecules computed by the new integrators, such as diffusion coefficients, orientation correlation times, and infrared (IR) spectra, are in good agreement with results obtained by the standard method. The comparison between the new integrators’ and the standard method’s integration time step sizes indicates that the resulting algorithm allows a 3.0fs long integration time step as opposed to the standard leap-frog Verlet method, a sixfold simulation speed-up. The accuracy of the method was confirmed, in particular, by computing the IR spectrum of water in which no blueshifting of the stretching normal mode frequencies is observed as occurs with the standard method.
Nondestructive evaluation of misfit dislocation densities in ZnSe∕GaAs heterostructures by x-ray diffuse scattering
Authors: Alexe G. , Heinke H. , Haase L. , Hommel D. , Schreiber J. , Albrecht M. , Strunk H. P.
Published: April 2005

Estimating the low densities of misfit dislocations in epitaxial layers in the early stages of relaxation is difficult, requiring a very sensitive method. The characteristic patterns of diffuse x-ray scattering are therefore utilized to quantify the linear density of misfit dislocations. This is demonstrated for ZnSe∕GaAs(001) heterostructures with ZnSe layer thickness slightly above the critical thickness. The densities that resulted from calculated patterns of x-ray scattering perpendicular to the diffraction vector are found to be in good agreement with the results of cathodoluminescence and transmission electron microscopy. Moreover, the diffuse x-ray scattering is used to quantitatively study the thermally induced increase in the linear densities of misfit dislocations. Samples are annealed at various temperatures for increasing periods successively and are analyzed between the annealing steps by high-resolution x-ray diffraction. The density of dislocations is found to saturate for longer annealing periods. The saturation value and the rate of increase of the dislocation density depend both on the annealing temperature and on the crystallographic direction.
Adaptive optical biocompact disk for molecular recognition
Authors: Peng Leilei , Varma Manoj M. , Regnier Fred E. , Nolte David D.
Published: April 2005

We report the use of adaptive interferometry to detect a monolayer of protein immobilized in a periodic pattern on a spinning glass disk. A photorefractive quantum-well device acting as an adaptive beam mixer in a two-wave mixing geometry stabilizes the interferometric quadrature in the far field. Phase modulation generated by the spinning biolayer pattern in the probe beam is detected as a homodyne signal free of amplitude modulation. Binding between antibodies and immobilized antigens in a two-analyte immunoassay was tested with high specificity and without observable cross reactivity.
Planar magnetoinductive lens for three-dimensional subwavelength imaging
Authors: Freire M. J. , Marqués R.
Published: April 2005

A planar near-field magnetoinductive lens operating in the microwave range is presented. The proposed device consists of two parallel planar arrays of metallic broadside coupled (BC) split-ring resonators (SRRs), or BC-SRRs. The power coming from a point-like source located in front of the lens is focused into a receiver located in free space beyond the lens. This focus is clearly separated from the back side of the lens, and has a size that is an order of magnitude smaller than the free space wavelength of the incoming field. The imaging properties of the device relies mainly on the excitation of magnetoinductive surface waves on the BC-SRR arrays. By simply scaling the BC-SRRs’ size, as well as the arrays periodicity, the operation frequency of the device can be tuned in a wide frequency range. Thus, the proposed design is potentially useful for many applications ranging from megahertz to terahertz.
Influence of the lateral movement on the levitation and guidance force in the high-temperature superconductor maglev system
Authors: Song Honghai , de Haas Oliver , Beyer Christoph , Krabbes Gernot , Verges Peter , Schultz Ludwig
Published: April 2005

After the levitation force relaxation was studied for different field-cooling height and working-levitation height, the high-temperature superconductor (HTS) bulk was horizontally moved in the lateral direction above the permanent magnet guideway. Both levitation and guidance force were collected by the measurement system at the same time. It was found that the decay of levitation force is dependent on both the maximum lateral displacement and the movement cycle times, while the guidance force hysteresis curve does not change after the first cycle. This work provided scientific analysis for the HTS maglev system design.
Carrier-density-dependent electron effective mass in Zn1−xMnxSe for ⩽x⩽0.13
Authors: Agarwal K. C. , Daniel B. , Grün M. , Feinäugle P. , Klingshirn C. , Hetterich M.
Published: April 2005

We used room-temperature infrared reflectivity measurements to investigate n-type chlorine-doped Zn1−xMnxSe epilayers (0⩽x⩽0.13). By making Drude-Lorentz-type multioscillator fits to our data, we extracted the optical electron effective mass (m*) in doped Zn(Mn)Se:Cl samples with different Mn content and doping concentrations. Our results indicate that m* in Zn1−xMnxSe is lower than that for ZnSe. In n-type chlorine-doped ZnSe samples with different doping concentrations, m* varied from 0.133m0 to 0.152m0, while in Zn0.87Mn0.13Se:Cl samples, we found a variation from 0.095m0 to 0.115m0 within ±9% experimental accuracy. From theoretical calculations, we estimate that the band-edge electron masses in ZnSe:Cl and Zn0.87Mn0.13Se:Cl should be about 0.132m0 and 0.093m0, respectively.
Remarkable polarization sensitivity of gold nanoparticle arrays
Authors: Canfield Brian K. , Kujala Sami , Kauranen Martti , Jefimovs Konstantins , Vallius Tuomas , Turunen Jari
Published: April 2005

In an array of low-symmetry, L-shaped gold nanoparticles, slight distortions of particle shape and arm lengths eliminate the array’s mirror plane. Such asymmetries induce large angular shifts (∼10°) of the resonant extinction axes directions from those of mirror-symmetric particles. The axes directions exhibit dispersion, as allowed by the lack of any structural features dictating them. The nanostructures are chiral, and evidence of optical activity is observed. Rigorous diffraction theory calculations qualitatively reproduce the data.
The relationships between characteristics of milking sheds and the attitudes to dairy cows, working conditions, and quality of life of dairy farmers
Authors: Maller C. J. , Hemsworth P. H. , Ng K. T. , Jongman E. J. , Coleman G. J. , Arnold N. A.
Published: April 2005

This study consisted of a survey of dairy farmers and their milking sheds at 198 Victorian dairy farms to examine the relationships between physical features in the milking shed and a number of job-related characteristics of the farmer, such as attitudes to handling cows and job satisfaction. Furthermore, farmers’ opinions of the effects of specific design features of the milking shed on cow behaviour were sought. A further objective of this survey was to use the relationships between shed characteristics and job-related characteristics of the farmer to identify, for future research, possible features of the milking shed that may affect cow behaviour.
There was substantial variation in both the behavioural beliefs of farmers about cow behaviour in the milking shed and reports by farmers on comfort and working conditions in the dairy, indicating that considerable opportunities exist to improve these key job-related characteristics. A principal component analysis (PCA) of the responses to the questions on job-related characteristics of the farmer identified 6 factors: 2 of the factors identified were related to behavioural beliefs by farmers about cow behaviour (labelled ‘Cow Movement’ and ‘Cow Behaviour’); one of the factors related to comfort of the farmer in the shed (labelled ‘Operator Comfort’); and 3 of the factors related to aspects of the quality of life of the farmer (labelled ‘Workload’, ‘Farmer Mood’, and ‘Job Characteristics’). Positive beliefs about both cow movement (factor called Cow Movement) and cow behaviour (factor called Cow Behaviour) were correlated with farmers being more positive about working in the dairy (factor called Operator Comfort; P < 0.05 and P < 0.01, respectively) and the characteristics of the job (factor called Job Characteristics; P < 0.01). These relationships suggest that improvements in cow behaviour may lead to improvements in both job satisfaction and the quality of life of the farmer. Furthermore, regression analysis revealed that a number of the shed features, such as height of the breast rail, presence of stall gates, length and width of the platform and solid side on first milking bail, were significant predictors of one or more of these 6 PCA factors. Although these results may not reflect causal relationships, these relationships between shed characteristics and a number of job-related characteristics of the farmer highlight the potential importance of shed design to both the cow and the farmer and provide a valuable guide in identifying features of milking sheds that require future examination as to their effects on cow behaviour.
Extending the Bayesian mixture model to incorporate spatial information in analysing sheep CAT scan images
Authors: Alston C. L. , Mengersen K. L. , Thompson J. M. , Littlefield P. J. , Perry D. , Ball A. J.
Published: April 2005

The purpose of CAT scanning in some animal science experiments is to provide estimates of the proportion of the tissues, fat, muscle, and bone present in an individual body, and compare some of the density characteristics. In this paper we present an extension to the hierarchical Bayesian Normal mixture model, which incorporates some of the information provided by the neighbouring pixels in a CAT scan image. This neighbour information is included in the model through the use of a Markov random field for the component allocation variable. This extended mixture model provides a more responsive fit to the local likelihood of the data than that of the independent mixture model. The effectiveness of this modelling technique is illustrated by comparing its performance with that of a Normal mixture model and a fixed boundary method in 3 examples. In these examples it is shown that the extended mixture model we propose is most useful in situations that involve only slight separation of components. The advantages of the model decline as the separation of components increases.
Quantitative patch and repeated open application testing in methyldibromo glutaronitrile‐sensitive patients
Authors: Schnuch A. , Kelterer D. , Bauer A. , Schuster Ch. , Aberer W. , Mahler V. , Katzer K. , Rakoski J. , Jappe U. , Krautheim A. , Bircher A. , Koch P. , Worm M. , Löffler H. , Hillen U. , Frosch P. J. , Uter W.
Published: April 2005

Contact allergy to methyldibromo glutaronitrile (MDBGN), often combined with phenoxyethanol (PE) (e.g., Euxyl K 400®), increased throughout the 1990s in Europe. Consequently, in 2003, the European Commission banned its use in leave‐on products, where its use concentration was considered too high and the non‐sensitizing use concentration as yet unknown. The 2 objectives of the study are (a) to find a maximum non‐eliciting concentration in a leave‐on product in MDBGN/PE‐sensitized patients, which could possibly also be considered safe regarding induction and (b) to find the best patch test concentration for MDBGN. We, therefore, performed a use‐related test (ROAT) in patients sensitized to MDBGN/PE (n = 39) with 3 concentrations of MDBGN/PE (50, 100 and 250 p.p.m. MDBGN, respectively). A subset of these patients (n = 24) was later patch‐tested with various concentrations (0.1, 0.2, 0.3 and 0.5% MDBGN, respectively). 15 patients (38%, 95% confidence interval (CI) = 23–55%) had a negative and 24 (62%; 95% CI = 45–77%) a positive overall repeated open application test (ROAT) result. 13 reacted to the lowest (50 p.p.m.), 8 to the middle (100 p.p.m.) and 3 to the highest concentration (250 p.p.m.) only. In those 13 reacting to the lowest ROAT concentration, dermatitis developed within a few days (1–7). The strength of the initial and the confirmatory patch test result, respectively, and the outcome of the ROAT were positively associated. Of the 24 patients with a use and confirmatory patch test, 15 reacted to 0.1% MDBGN, 16 to 0.2%, 17 to 0.3% and 22 to 0.5%. With the patch test concentration of 0.5%, the number of ROAT‐negative patients but patch‐test‐positive patients increases considerably, particularly due to + reactions. A maximum sensitivity of 94% (95% CI = 70–100%) is reached with a patch test concentration of 0.2%, and is not further improved by increasing the concentration. However, the specificity decreases dramatically from 88 (95% CI = 47–100%) with 0.2% to a mere 12.5% (95% CI = 0–53%) with 0.5%. It can be concluded (a) that for MDBGN 0.2% is very likely the best patch test concentration and (b) that 50 p.p.m. in a leave‐on product can elicit contact dermatitis in sensitized persons. We were, therefore, unable to find a safe, still microbicidal, concentration for leave‐on products. By contrast, with other contact allergens, dose–response use tests may be able to identify a non‐eliciting concentration, which could give valuable clues to a non‐inducing (i.e., safe) concentration in products.
Recombinant FVIIa in the management of intracerebral haemorrhage in severe thrombocytopenia unresponsive to platelet‐enhancing treatment
Authors: Barnes C. , Blanchette V. , Canning P. , Carcao M.
Published: April 2005

summary.  Intracranial haemorrhage (ICH) is a dramatic and potentially life‐threatening presentation of children with thrombocytopenia. Management is limited to supportive care. Recent evidence suggests that ongoing bleeding following the initial ICH may result in greater neurological morbidity and mortality. Haemostatic agents, including recombinant factor VIIa (rFVIIa), a product licensed for use in patients with haemophilia and inhibitors, may be helpful in reducing bleeding in children with refractory thrombocytopenia.

We present the case of a 16‐year‐old girl with severe refractory immune thrombocytopenia, who presented with a major ICH and responded to treatment that included rFVIIa and platelet transfusions. The dose of rFVIIa was empirically chosen and based on reported cases in the literature. The case highlights a number of issues regarding off‐label use of rFVIIa and demonstrates the need to prospectively collect accurate information on the off‐label use of this new potentially useful medication.
Managing passively acquired autoimmune neonatal neutropenia: a case study
Authors: Fung Y. L. , Pitcher L. A. , Taylor K. , Minchinton R. M.
Published: April 2005

summary.  Pregnant women with autoimmune neutropenia (AIN) and circulating neutrophil‐specific autoantibodies can deliver neutropenic neonates at risk of sepsis. We report the case of a woman who had two such pregnancies. The woman had been on prophylactic granulocyte colony‐stimulating factor (G‐CSF) treatment, but this was ceased prior to conception in both pregnancies. In the first pregnancy, there was no monitoring or interventions, and the neonate was neutropenic and required intensive care treatment. In the second pregnancy, the maternal neutrophil autoantibody level was monitored, and G‐CSF treatment was introduced in the third trimester. The second infant had no neutropenia at delivery and an excellent Apgar score. We discuss the management strategy in the second pregnancy that included monitoring of serial titres of the maternal autoantibody and the introduction of G‐CSF in the third trimester, which may have contributed to a more favourable clinical outcome. This may assist other clinicians faced with similar dilemmas in the future.
About the role of boundary conditions on compositional imaging with a scanning electron microscope
Authors: MERLI P. G. , MORANDI V. , CORTICELLI F.
Published: April 2005

We consider the effects of different boundaries on the visibility of a specimen detail providing a compositional contrast in scanning electron microscopy, operating with backscattered electrons or secondary electrons. An object characterized by a gradual variation in composition, an As‐doped region in Si, is investigated. The different boundaries in the cross‐sectioned specimen correspond to the absence or presence of a poly‐Si layer on top of the implanted region, deposited after the annealing treatment. It is shown that the interpretation model used for image formation is of paramount relevance for understanding the experimental results, indicating that the boundaries of the doped region are important in hindering or enhancing its visibility. The relevance of experimental parameters such as electron energy and probe dimension is also reported.
An optical differential scanning calorimeter cryomicroscope
Authors: YUAN S. , DILLER K. R.
Published: April 2005

An optical‐DSC system was designed, built, tested, calibrated and verified to incorporate into a single device the capability for simultaneous optical cryomicroscopy and differential scanning calorimetry (DSC). This instrument can be used to obtain both visual and thermal data for an individual specimen subjected to a defined freezing and thawing protocol with very little compromise in quality or range of data available in comparison with dedicated single instruments. Temperature and caloric calibrations were performed based on phase transition states in water, n‐dodecane and n‐decane. The instrument has proven effective for process analysis in living cells and in foodstuffs.
Anthropometric measurements for neonates, 23 to 29 weeks gestation, in the 1990s
Authors: Karna Padmani , Brooks Kevin , Muttineni Jyotsna , Karmaus Wilfried
Published: April 2005

Reference data describing weight, length, and head circumference (anthropometric measurements) at birth were published by Lubchenco and Usher before 1970. Few attempts have been made to investigate whether these data are appropriate for today's cohort of preterm neonates. We analysed anthropometric data for neonates born between 23 and 29 weeks’ gestation. Reference charts were developed from the measurements obtained from neonatal records, and gestational age, obtained from maternal charts, on 975 neonates delivered at four neonatal centres in Michigan during 1992 and 1997. The analysis was confined to children with gestational age that was consistent or within 7 days by last menstrual period, obstetric examination, ultrasound and neonatal determinations. At 23 to 29 weeks’ gestation, ethnicity and multiple births did not have any significant impact on birthweight but girls were lighter. We compared our anthropometric charts with those presently being used at many neonatal centres. In our study, physical measurements at birth of preterm neonates born between 1992 and 1997 were significantly different from those currently used to assess growth status. Furthermore data derived from published studies that utilised birth certificates with gestational age based on last menstrual period seem to overestimate birthweight. For preterm infants, our findings are concordant with recently published values from 18 states of the US.

Because of improved survival, gestational age assessment and perinatal care of preterm neonates, development of new reference anthropometric measurements for neonates is overdue. Our Michigan data of 23–29 weeks preterm provides new national reference values, which we recommend for use in US neonatal centres for extremely preterm neonates.
Effects of aluminum on DNA synthesis, cellular polyamines, polyamine biosynthetic enzymes and inorganic ions in cell suspension cultures of a woody plant, Catharanthus roseus
Authors: Minocha Rakesh , Minocha Subhash C. , Long Stephanie L. , Shortle Walter C.
Published: April 2005

Increased aluminum (Al) solubility in soil waters due to acid precipitation has aroused considerable interest in the problem of Al toxicity in plants. In the present study, an in vitro suspension culture system of Catharanthus roseus (L.) G. Don was used to analyze the effects of aluminum on several biochemical processes in these cells. The aliphatic polyamines, spernine and spermidine, and their precursor, putrescine, have been implicated in a number of stress responses of plants. Addition of 0.2, 0.5 or 1.0 mM AlCl, to cells cultured for 3 days caused a small but significant increase in cellular levels of putrescine at 4 h followed by a sharp decline by 16 h. There was no further decline in levels of putrescine during the next 32 h. Spermidine levels did not change appreciably compared to those in the control cultures. However, spermine levels increased by 2–3–fold at 24 and 48 h. Cellular activities of arginine decarboxylase (ADC: EC 4.1.1.19) and S‐adenosylmethionine decarboxylase (SAMDC: EC 4.1.1.50) were both inhibited by 20–25% at 4 and 7 h. Ornithine decarboxylase (ODC; EC 4.1.1.17) was less than 10% of ADC activity at all times. Whereas all concentrations of Al caused a slight decrease in total cell number, cell viability was affected only by 1.0 mM Al. There was a decrease in the cellular levels of Ca, Mg, Na, K, Mn. P and Fe in the cells treated with Al at 4 h, but a significant increase by 16 and 24 h. The results presented here suggest that both the absolute amount of Al and the length of exposure to it are important for cell toxicity.