bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and mortality of transient shrimp populations (Farfantepenaeus spp.) in a coastal lagoon of Mexico: role of the environment and density-dependence
Authors: Pérez-Castañeda Roberto , Defeo Omar
Published: December 2004

The influence of environmental (temperature, salinity, aquatic vegetation) and density-dependent (abundance of recruits) factors on growth and mortality of four Farfantepenaeus species were evaluated during their period of estuarine residence, through a 2-year field study at Celestun lagoon, Mexico. Growth rates of the three most abundant species (F. brasiliensis, F. duorarum, F. notialis) were positively related with temperature and aquatic vegetation biomass, whereas some significant relationships between environmental factors and mortality rates were also demonstrated. Our results suggest that density-dependent processes regulate growth and mortality in these shrimp populations. Density-dependent mortality was also suggested by a strong compensatory relationship between recruits and juveniles. We conclude that population dynamics of Farfantepenaeus shrimps during their estuarine phase seem to be driven by the combined forces of density-dependent and environmental factors operating together.
Construct Validity of the Chinese Version of the Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH-HKPWH)
Authors: LEE E. W. C. , CHUNG M. M. H. , LI A. P. S. , LO S. K.
Published: December 2004

The study evaluated the construct validity of the Chinese Hong Kong version of the disabilities of the arm, shoulder and hand questionnaire (DASH-HKPWH). Three hundred and thirty four patients with a broad range of upper extremity disorders were recruited into the study. Each completed DASH-HKPWH and SF-36 forms and their pain intensity (numeric pain rating scale) and grip strength were also measured. The mean DASH-HKPWH score was 40 (SD = 20). Principal component factor analysis identified a single factor, which accounted for 47% of the total variance. Pearson correlation was applied to assess convergent and divergent validity of the DASH-HKPWH by comparison with the above-mentioned subjective and objective measurements. Our findings were comparable to the DASH of other languages.
Dual Energy X-Ray Absorptiometry (DXA): Can it Detect Acute Scaphoid Fractures?
Authors: STEPHEN A. B. , PYE D. , LYONS A. R. , ONI J. A. , DAVIS T. R. C.
Published: December 2004

This prospective study investigated whether dual energy X-ray absorptiometry (DXA) could detect acute scaphoid fractures. We blindly compared 10 normal and 10 fractured scaphoid images produced with a new technique of DXA scan analysis. This measured and plotted the density of the scaphoid throughout its length, producing a linear graph of the scaphoids’ density instead of a single area (g/cm2) measurement of bone density.

These new plots only detected six of the 10 fractures and suggested that four of the normal controls were fractured. Thus, this technique of DXA scan analysis is neither sensitive nor specific for the detection of acute scaphoid fractures.
A Comparative Study of Outcome between the Neuflex and Swanson Metacarpophalangeal Joint Replacements
Authors: DELANEY R. , TRAIL I. A. , NUTTALL D.
Published: December 2004

This prospective double blind trial compares the clinical findings of Swanson and Neuflex metacarpophalangeal joint replacements in patients with rheumatoid arthritis, up to 2 years follow-up. There were 37 joints (10 patients) in the Swanson group and 40 joints (12 patients) in the Neuflex group. Assessments of range of movement, grip strength and hand function were undertaken in a double blind fashion, preoperatively and up to 2 years following implantation. The mean and standard deviation of the data were calculated. A two-tailed student’s t-test was used when comparing groups of data. An X-ray analysis was also undertaken to identify any implant failure.

There was no significant difference between the two groups with respect to flexion and extension before surgery. At follow-up there was also no significant difference in the extensor lag, with mean extension lags of 19° and 16° for the Swanson and Neuflex implants, respectively. However, there was a significant difference in flexion, with mean active flexion values of 59° and 72° for the Swanson and Neuflex implants, respectively. There were no differences between the two groups in respect to arc of metacarpophalangeal joint motion, ulnar deviation, grip strength or the SODA function test at follow-up. At this early stage there was no evidence of any case of implant failure.

In conclusion, patients who underwent Neuflex metacarpophalangeal joint replacements obtained greater flexion than those who underwent a Swanson replacement.
Stock market speculation and managerial myopia
Authors: Nyman Ingmar
Published: December 2004

This paper extends the analysis of managerial share price concerns by allowing informed trading in the stock market. It is shown that because they decrease the manager's information advantage vis‐à‐vis the stock market, individual investors who trade on private information improve the efficiency of corporate investment. This improvement does, however, fall short of first‐best efficiency. Moreover, a stronger managerial share‐price concern increases the expected profit from informed trading. Hence, by encouraging individual investors to collect information about corporate decisions and trade on it, managerial myopia tends to automatically bring forth a partial solution to the problems that it causes.
Last century changes in ocean wind wave height from global visual wave data
Authors: Gulev Sergey K. , Grigorieva Vika
Published: December 2004

Centennial time series of visually observed wave height were derived from the International Comprehensive Ocean‐Atmosphere Data Set along the major ship routes in the World Ocean and homogenized. They demonstrate positive trends in significant wave height over the North Pacific with a maximum of 8–10 cm/decade in the northeast Pacific. In the North Atlantic and other basins significant upward changes (up to 14 cm/decade) are observed only for the last 50 years and not for centennial records. Long‐term changes in wind wave height are closely associated with the North Atlantic Oscillation in the Atlantic and with North Pacific Oscillation and El‐Niño–Southern Oscillation in the Pacific.
A comparison of the circulation patterns over the Southwestern Atlantic Shelf driven by different wind stress climatologies
Authors: Palma Elbio D. , Matano Ricardo P. , Piola Alberto R. , Sitz Lina E.
Published: December 2004

We compare the oceanic circulation patterns over the Southwestern Atlantic Shelf (SWAS) forced by nine different wind stress climatologies. The largest differences are observed in experiments forced with the Hellerman and Rosenstein [1983, hereafter HR83] and Trenberth et al. [1990, hereafter TR90] winds. HR83 shows a general northeastward flow near the shelf break. The TR90 results shows a bifurcating path south of ∼40°S and a poleward flow north of 35°S. The most robust circulation patterns are a broad northward flow and the generation of coastal re‐circulation cells in southern Patagonia and the development of a southward jet in the inner portion of the South Brazil Bight.
On the dynamics of interdecadal thermocline depth and sea surface temperature variability in the low to mid‐latitude Pacific Ocean
Authors: McGregor Shayne , Holbrook Neil J. , Power Scott B.
Published: December 2004

The role of upper ocean dynamics in generating interdecadal sea surface temperature (SST) variations is investigated with the help of the Australian Bureau of Meteorology Research Centre coupled general circulation model (CGCM) and a first baroclinic mode (“shallow‐water”) ocean model (SWM). An empirical orthogonal function analysis is performed on the lowpass filtered SST and vertically averaged temperature in the upper 300 m anomaly data output from a 100‐year CGCM simulation. The dominant mode SST spatial pattern and time variability is consistent with the Interdecadal Pacific Oscillation. The SWM is forced by wind stresses from the CGCM 100‐year simulation to investigate the role of oceanic Rossby and Kelvin wave propagation on thermocline depth variations. The SWM produces variability similar to the CGCM interdecadal variability. We conclude that large scale wind forced upper ocean dynamics play a dominant role in generating interdecadal upper ocean temperature variations on decadal and longer timescales.
The reflectance spectra of opal‐A (0.5–25 μm) from the Taupo Volcanic Zone: Spectra that may identify hydrothermal systems on planetary surfaces
Authors: Goryniuk Michelle C. , Rivard Benoit A. , Jones Brian
Published: December 2004

Opal‐A, the main component of siliceous sinters in many terrestrial hydrothermal systems, is a hydrated silicate that commonly incorporates silicified microorganisms. The detection of opal‐A on the surface of Mars, therefore, may carry important implications in the search for extraterrestrial life. Sinters from the discharge apron of Ohaaki Pool (North Island, New Zealand) yielded reflectance spectra (wavelengths between 0.5–25 μm) that indicate the presence of absorbed water, trapped water, and silanol in opal‐A. Two classes (1 and 2) of reflectance spectra were detected between the wavelengths of 6–13 μm. The Class‐1 spectrum is similar to existing opal spectra, and was collected from well‐consolidated samples that had low porosity. The Class‐2 spectrum is unique when compared to the spectra of other silica polymorphs, and was collected from poorly consolidated samples that had high porosity.
Latitude survey observations of neutron monitor multiplicity
Authors: Bieber J. W. , Clem J. M. , Duldig M. L. , Evenson P. A. , Humble J. E. , Pyle R.
Published: December 2004

We have recently augmented the electronics for our neutron monitor (NM) latitude survey so as to record the elapsed time (δT) between detected neutrons in each proportional tube, in order to examine time correlations in the data as a function of cutoff rigidity and primary spectrum. We quantify the dependence of counting rate on dead time, with particular focus on the longer dead times that were once employed in FSU/Russian stations. Our observations show that monitor dead time has little influence on the observed depth of Forbush decreases, indicating that the cosmic ray spectral shape is little changed in the decrease. However, the use of a different dead time significantly alters the response of the monitor as a function of cutoff rigidity. In spite of the general success of our calculation in reproducing the data, unexplained discrepancies are still present.
Influence of normal stress and grain shape on granular friction: Results of discrete element simulations
Authors: Guo Yonggui , Morgan Julia K.
Published: December 2004

Laboratory experiments of granular shear deformation demonstrate that loading conditions and grain characteristics can significantly affect the macroscopic friction of a granular material under shear. We have examined the variation of maximum sliding friction with normal stress and grain shape using a version of the distinct element method (DEM) that includes bonds between adjacent particles. In this way, arbitrarily shaped grains can be generated to reproduce more realistic fault gouge with a range of grain sizes and shapes. Two types of grains were designed to represent quartz gouge: rounded grains composed of seven close‐packed particles and triangular grains composed of six close‐packed particles. DEM experiments were conducted by shearing granular assemblages with different grain shape distributions using the identical boundary configurations (i.e., wall surface roughness) over a range of normal stresses from 5 to 100 MPa and were compared to equivalent experiments using reference circular particle assemblages. The results show an inverse power law relationship between normal stress and maximum sliding friction in all cases, where both its coefficient and exponent are dependent on gouge angularity. Under normal stress over 20 MPa, triangular grain assemblages exhibited the highest frictional strength and also the highest abundance of rotating grains, demonstrating that enhanced grain rolling alone does not explain the low frictional strength of simulated granular assemblages.
Secondary aerosol formation in continental outflow conditions during ACE‐Asia
Authors: Buzorius G. , McNaughton C. S. , Clarke A. D. , Covert D. S. , Blomquist B. , Nielsen K. , Brechtel F. J.
Published: December 2004

Ground‐based aerosol size distribution measurements at the Gosan, Korea, sampling site during ACE‐Asia showed occasionally elevated concentrations of nucleation mode aerosol particles, with subsequent growth to the Aitken mode. Similar results from aircraft and ship‐based measurements at around the same time indicated that at least one event exhibited a broad spatial extent. One of the most pronounced events, with total number concentrations of particles as high as 105 cm−3, occurred on 12 April at the same time as a large dust event, when the total aerosol surface area of particles with diameters less than 10 μm was increase by a factor of 1.7 compared to the average value for the study. Aircraft data showed layers of enlarged SO2 concentration coinciding with an increased aerosol total number concentration, with the highest detected SO2 concentration being 12 ppbv and aerosol number concentration reaching 8 × 104 cm−3 at 800 m altitude. Aircraft data showed that newly formed particles and dust were stratified in different layers in marine environment and transported to the surface close to the island. Atmospheric thermodynamic data suggested that particles were formed above the marine boundary layer and transported by vertical mixing toward the surface as a result of a 3 K north‐to‐south increase in the sea surface temperature. This temperature increase changed atmosphere stratification from stable to neutral/slightly unstable and deepened the internal mixed layer from below 300 m to above 800 m altitude. Measured hygroscopic properties of nucleation mode aerosol particles were consistent with those of ammonium sulfate particles. Here we reported a novel case study of tropospheric aerosol formation identifying particle chemical composition of nucleation mode aerosols in real time by measuring their water uptake properties. Then we demonstrated that particles formed in a layer aloft and were transported to the ground site by growth of the mixed boundary layer while nucleation was chemically induced and did not require turbulent mixing.
Sea‐salt vertical profiles over the Southern and tropical Pacific oceans: Microphysics, optical properties, spatial variability, and variations with wind speed
Authors: Shinozuka Yohei , Clarke Antony D. , Howell Steven G. , Kapustin Vladimir N. , Huebert Barry J.
Published: December 2004

About 100 vertical profiles of marine aerosol were contrasted between two remote regions over the Southern Ocean and the equatorial Pacific. Real‐time thermal analysis of particles at near 40°C, 150°C, and 300°C resolved the volatile (mostly sulfate and organic) and refractory (mostly sea salt) size distributions continuously throughout two major aircraft campaigns. The average sea‐salt contributions to aerosol optical depths (AOD) in the marine boundary layer over the Southern Ocean and tropical Pacific were 0.037 (63% of the total column AOD) and 0.022 (31%), respectively, while the volatile component contributed 0.011 (19%) and 0.038 (53%), respectively. This shows the large difference in relative importance of sea salt and volatile components for regions with different residence times and source strengths. The total column AOD is estimated to be 0.037, 0.043, and 0.090 for 0–4, 4–8, and 8–12 m s−1, respectively, over the Southern Ocean, and 0.060, 0.062, and 0.128 for 3–5, 5–7, and 7–9 m s−1, respectively, over the tropical Pacific. Wind speed was a good indicator of sea‐salt concentrations on a campaign average basis but a poor indicator on a case‐by‐case basis. This highlights the important effect of removal, wind duration, and fetch on sea‐salt variability. Variability in the marine aerosol was assessed statistically for 96 circular flight legs of about 60 km diameter. This mesoscale variability increased with altitude and resulted in variations in column AOD of about 25% over these spatial scales. Hence mesoscale variability is an important concern for satellite remote sensing, closure studies, and model validation even for this nominally homogeneous clean marine atmosphere.
Dusty plasma effects in Saturn's magnetosphere
Authors: Horányi M. , Hartquist T. W. , Havnes O. , Mendis D. A. , Morfill G. E.
Published: December 2004

Comets, planetary rings, exposed dusty surfaces, and the zodiacal dust cloud are all examples of environments where dusty plasma effects establish the size and spatial distributions of small grains. Simultaneously, dust often influences the composition, density, and temperature of the plasma surrounding it. The dynamics of charged dust particles can be surprisingly complex and fundamentally different from the well‐understood limits of gravitationally dominated motions of neutral particles or the adiabatic motion of electrons and ions in electromagnetic fields that dominate gravity. In this review we focus on observations that are best explained by theories concerning dusty plasma effects at Saturn. In addition to presenting our current models we also discuss our expectations for new discoveries based on existing observations at Jupiter or on purely theoretical considerations. Our intent is to give an up‐to‐date overview of dusty plasma effects in Saturn's magnetosphere and to draw attention to several outstanding problems that could be resolved by the Cassini mission.
A physically based model of the effects of forest roads on slope stability
Authors: Borga Marco , Tonelli Fabrizio , Selleroni Jacopo
Published: December 2004

Road networks in mountainous forest landscapes have the potential to increase the susceptibility to shallow landsliding by altering subsurface flow paths. In this paper a road interception/rerouting grid‐based model is developed and coupled with a hydrogeomechanical, threshold‐based model for slope instability. Model results allow quantification of the influence of roads on shallow landsliding hazard across a landscape and generation of hypotheses about the broader geomorphic effect of roads. The model is applied to three sites in northeastern Italy to study the influence of three different procedures for upslope drainage area computation on model results. The three procedures are a single‐flow direction procedure (D8), a multiple‐flow direction procedure (MF), and an algorithm based on proportioning flow between two downslope pixels (DINF). Model results are highly sensitive to upslope drainage area algorithm choice. It is shown that D8 and MF are unsuitable for road impact evaluation due to grid bias (D8) and excessive dispersion (MF). Model implementation with the DINF procedure results in a reasonable compromise between the artifacts that characterize the other two algorithms. Observed landslide patterns are broadly consistent with model estimates, a finding that underscores the utility of this simple approach for predicting the geomorphic effects of forest roads constructed on steep slopes. The approach used in this study may be useful for defining criteria for road design that reduce the effects of roads on geomorphic processes.
Identification, purification and characterization of a novel human blood protein with binding affinity for prostate secretory protein of 94 amino acids
Authors: REEVES Jonathan R. , XUAN Jim W. , ARFANIS Katerina , MORIN Catherine , GARDE Seema V. , RUIZ Marcia T. , WISNIEWSKI Jan , PANCHAL Chandra , TANNER Jerome E.
Published: December 2004

PSP94 (prostate secretory protein of 94 amino acids), an abundant protein within semen, has reported local functions within the reproductive tract and reported systemic functions. Mechanisms of action remain poorly understood, but binding to undefined molecules within the prostate, pituitary, testis and blood may initiate some of these actions. PSP94 serum measurements, especially of bound and free forms, have potential clinical utility in prostate cancer management. Identification of the binding molecules will help in the understanding of PSP94's action, and enable further development of PSP94 serum assays. PSPBP (PSP94-binding protein) was purified from human serum by ammonium sulphate fractionation, ion-exchange and affinity chromatography. The glycosylated protein ran as two bands on SDS/PAGE (70 and 95 kDa). N-terminal sequencing yielded a 30-amino-acid sequence, identical with the translated N-terminal region of a previously published cDNA (GenBank® accession number AX136261). Reverse transcriptase PCR and plaque hybridization demonstrated PSPBP mRNA in peripheral blood leucocytes and in a prostate cDNA library. Northern blotting showed 2 kb mRNA species in prostate, testis, ovary and intestine. Immunohistochemistry demonstrated PSPBP in tissues, including pituitary and Leydig cells, supporting a role for PSP94 in hormonal control at the pituitary gonadal axis. ELISA demonstrated that PSPBP levels were significantly lower (P=0.0014) in the serum of a prostate cancer population (n=65) compared with a control population (n=70). PSPBP identification will help the understanding of PSP94's functions and facilitate ELISA development to address the clinical value of PSP94 serum assays.
Identification, molecular cloning and functional characterization of a novel NADH kinase from Arabidopsis thaliana (thale cress)
Authors: TURNER William L. , WALLER Jeffrey C. , SNEDDEN Wayne A.
Published: December 2004

NADH kinase (NADHK; ATP:NADH 2′-phosphotransferase; EC 2.7.1.86), an enzyme that preferentially utilizes NADH as the diphosphonicotinamide nucleotide donor, has been identified for the first time in plants. Low activity (0.4 nmol of NADPH produced/min per mg of protein) was observed in clarified protein extracts from Arabidopsis thaliana (thale cress) cell suspension cultures. However, unlike an NADHK from yeast (Saccharomyces cerevisiae) (POS5), the enzyme from Arabidopsis did not associate with the mitochondria. NADHK was cloned (gi:30699338) from Arabidopsis and studied as a recombinant protein following affinity purification from Escherichia coli. The enzyme had a pH optimum for activity of 7.9 and a subunit molecular mass of 35 kDa. Analytical gel filtration demonstrated that the recombinant enzyme exists as a dimer. Hyperbolic saturation kinetics were observed for the binding of NADH, ATP, free Mg2+ and NAD+, with respective Km values of 0.042, 0.062, 1.16, and 2.39 mM. While NADHK could phosphorylate NADH or NAD+, the specificity constant (Vmax/Km) for NADH was 100-fold greater than for NAD+. The enzyme could utilize UTP, GTP and CTP as alternative nucleotides, although ATP was the preferred substrate. PPi or poly-Pi could not substitute as phospho donors. PPi acted as a mixed inhibitor with respect to both NADH and ATP. NADHK was inactivated by thiol-modifying reagents, with inactivation being decreased in the presence of NADH or ATP, but not NAD+. This study suggests that, in Arabidopsis, NADP+/NADPH biosynthetic capacity could, under some circumstances, become uncoupled from the redox status of the diphosphonicotinamide nucleotide pool.
A density-functional theory investigation of 3-nitro-1,2,4-triazole-5-one dimers and crystal
Authors: Xiao He-Ming , Ju Xue-Hai , Xu Li-Na , Fang Guo-Yong
Published: December 2004

Density-functional method with different basis sets was applied to the study of the highly efficient and low sensitive explosive 3-nitro-1,2,4-triazole-5-one (NTO) in both gaseous dimer and its bulk state. The binding energies have been corrected for the basis set superposition errors. Six stable dimers (II–VII) were located. The corrected binding energy of the most stable dimer VII is predicted to be −53.66 kJ/mol at the B3LYP/6-311++G** level. It was found that the structures of the more stable dimers (V–VII) are through the hydrogen bonding interaction between the carbonyl oxygen and the azole hydrogen of 3-nitro-1,2,4-triazole-5-one. The changes of Gibbs free energies (ΔG) in the processes from the monomer to the dimers at 298.15 K are 8.51, 0.90, 0.35, −8.74, −10.67, and −11.06 kJ/mol for dimers from II to VII, respectively. Dimers V–VII, possessing cyclic structures, can be spontaneously produced from the isolated monomer at room temperature. The lattice energy is −156.14 kJ/mol, and this value becomes to −150.43 kJ/mol when a 50% correction of the basis set superposition error was adopted. The frontier bands are quite flat. Judged from the value of band gap of 4.0 eV, it may be predicted that 3-nitro-1,2,4-triazole-5-one is an insulator. Most atoms in NTO, with the exception of C5 atom and the nitro atoms, make up the upper valence bands. In contrast, the lower conduction bands mainly consist of the nitro N and O atoms. The population of the C–NO2 bond is much less than those of the other bonds and the detonation may be initiated by the breakdown of this bond.
Absence of charge inversion on rodlike polyelectrolytes with excess divalent counterions
Authors: Wen Qi , Tang Jay X.
Published: December 2004

Filamentous viruses such as fd and M13 are highly charged rodlike polyelectrolytes. In this study, we employ fd virus to test the recent prediction of charge inversion [Nguyen, Rouzina, and Shklovskii, J. Chem. Phys. 112, 2562 (2000)]. Light scattering measurements show bundle formation and resolubilization of fd viruses when MgCl2 was added from 0 to 600 mM. The effective charge of fd was studied by measuring their electrophoretic mobility using a filament tracking method uniquely suited for the system. Monte Carlo simulations were performed under canonical ensemble to predict the charge distribution around the rodlike virus. Charge inversion, which has been suggested theoretically to accompany with bundle resolubilization, was not observed in either experiments or simulations. A modified analysis of force balance is called upon to account for these new findings.
Orientational motion of nitroxides in molecular glasses: Dependence on the chemical structure, on the molecular size of the probe, and on the type of the matrix
Authors: Kirilina Evgeniya P. , Grigoriev Igor A. , Dzuba Sergei A.
Published: December 2004

Echo detected electron paramagnetic resonance (EPR) study of orientational molecular motion of nitroxide spin probes in glassy solvents was performed by evaluating the anisotropic transverse relaxation rate 1/T2 at different positions of the EPR spectrum. Experiments were done on nitroxides of different sizes and shapes, in different solvent glasses, with different deuteration degree, and at different temperatures. We found that the properties of the solvent glass have a much stronger impact on the relaxation rate than the size and shape of the nitroxide have. We concluded that the anisotropic relaxation is induced by reordering of the solvent cage and not by small angle fluctuations of the nitroxide in the cage or intramolecular motion of nitroxide.
Thermo reflectance bolometry
Authors: Mitko S. V. , Oudalov A. Yu. , Udalov Yu. B. , Peters P. J. M. , Boller K. J.
Published: December 2004

An approach to bolometry has been developed. It is based on the measurements of optical reflectivity change of a thin metal layer deposited on a transparent substrate. The reflectivity change results from the temperature rise due to absorption of energetic particles or x rays. The sensor of the bolometer has no ohmic contact with the measuring unit, making this method well suited for an environment with strong electromagnetic noise interference. The technique was applied to characterize a method for the generation of intense electron beams in a dense gas. Very high efficiency for the e-beam generation (up to 95%) was measured.
Interfacial oxide formation from intrinsic oxygen in W–HfO2 gated silicon field-effect transistors
Authors: Preisler E. J. , Guha S. , Copel M. , Bojarczuk N. A. , Reuter M. C. , Gusev E.
Published: December 2004

We report the effects of ultrahigh vacuum and nitrogen annealing on self-aligned W-gated HfO2 n-field-effect transistors. While rapid thermal annealing in a nitrogen ambient significantly improved the channel mobility, there is a corresponding increase in the gate dielectric thickness of up to 20Å. Here we show that this increase is due to the formation of interfacial oxides between the HfO2 and the silicon, caused by the diffusion of oxygen from the W gates. The results point to the importance of oxygen solubility in metals, which may be significant in many candidate gate electrodes.
Electrically switchable lasing from pyrromethene 597 embedded holographic-polymer dispersed liquid crystals
Authors: Jakubiak Rachel , Natarajan Lalgudi V. , Tondiglia Vincent , He Guang S. , Prasad Paras N. , Bunning Timothy J. , Vaia Richard A.
Published: December 2004

One-dimensional photonic band gap (PBG) materials created from holographic polymer dispersed liquid crystals (H-PDLCs) provide enhanced light localization in an organic electro-optic device. Distributed feedback within the reflection notch of a H-PDLC grating narrowed the bandwidth of pyrromethene 597 fluorescence from 56 to 8.4nm at a lasing threshold of 0.12mJcm−2, compared to 2.6mJcm−2 required to observe amplified spontaneous emission in a nonstructured, but comparable floodlit (PDLC) sample. Application of an electric field (10–40V∕μm) continuously decreased the diffraction efficiency of the grating and the commensurate dynamic lasing intensity thus demonstrating electrically modulated gain from an optically pumped, all-organic PBG.
Photoemission study of energy-band alignment for RuOx∕HfO2∕Si system
Authors: Li Q. , Wang S. J. , Li K. B. , Huan A. C. H. , Chai J. W. , Pan J. S. , Ong C. K.
Published: December 2004

Conductive oxides RuOx as alternative electrode on high-κ HfO2 gate dielectric have been fabricated by ultrahigh-vacuum sputtering and subsequently oxidized using oxygen plasma. The energy-band alignment for the RuOx∕HfO2∕Si system and the oxidation-state dependence of barrier height for RuOx contacting to HfO2 dielectrics has been analyzed by x-ray photoemission spectroscopy. The valence- and conduction-band offsets of HfO2∕Si are determined to be 3.05±0.1 and 1.48±0.1eV, respectively. The barrier heights for the RuOx contacting to HfO2 are oxidation-state dependent, in the range of 1.95–2.73eV.
Superconducting properties of MgB2 films electroplated to stainless steel substrates
Authors: Abe Hideki , Nishida Kenji , Imai Motoharu , Kitazawa Hideaki , Yoshii Kenji
Published: December 2004

Superconducting MgB2 films have been fabricated on stainless steel substrates by means of electroplating in a molten electrolyte composed of MgCl2, MgB2O4, NaCl, and KCl containing a fractional amount of CuCl2. Microscopic observation has revealed that the electroplated films and substrates are combined with each other through Cu-rich layers at the interfaces. Transport measurements have shown that the electroplated MgB2 films possess an upper critical field, Hc2(0), of 28T, an irreversibility field, Hirr(0), of 13T, and a critical current density, Jc(5K,0T), of 25 000A∕cm2, which suggests that the electroplating in molten salts is a promising alternative to the powder-in-tube method for the fabrication of MgB2 tapes.
Photoelectrical properties of molecular layer consisting of chlorophyll a∕ferredoxin heterostructure
Authors: Nam Yun Suk , Choi Jeong-Woo , Lee Won Hong
Published: December 2004

Photoelectrical properties of biomolecular heterostructures are investigated. Ferredoxin and chlorophyll a were used as an electron acceptor and a sensitizer in the heterostructure by mimicking the photosynthesis. Self-assembly layer of ferredoxin was formed on Au-coated glass, and then chlorophyll a was deposited onto the ferredoxin layer by Langmuir–Blodgett method. The photoinduced current flow was observed by repeated step illumination of 488nm light irradiation. The rectifying property by the scanning-tunneling-spectroscopy-based current–voltage characteristic was achieved in the ferredoxin∕chlorophyll a heterostructure. The ferredoxin∕chlorophyll a heterostructure was functioned as the molecular diode and switching device with photocurrent generation and rectifying property. Proposed molecular diode can be usefully applied for the development of molecular-scale bioelectronic devices such as the diode, switch, and solar cell.
Atomic arrangement at the Au∕p-GaN interface in low-resistance contacts
Authors: Omiya H. , Ponce F. A. , Marui H. , Tanaka S. , Mukai T.
Published: December 2004

The atomic arrangement of Ni∕Au contacts on p-type GaN has been studied by transmission electron microscopy (TEM). The initial Au∕Ni∕GaN structure transforms upon annealing at 400–600°C into Ni∕Au∕GaN. The Au layer consists of thin platelets with uniform thickness. High-resolution TEM reveals an atomically sharp interface between GaN and Au, with no intermediate phases present. The epitaxial relationship between the Au layer and the GaN film is (111)Au‖(0002)GaN, and [11¯0]Au‖[112¯0]GaN. Analysis of TEM images shows that Au is directly in contact with Ga atoms, with no evidence of presence of Ni. The interface separation corresponds to covalent Ga and metallic Au, with a bond length of ∼2.5Å. This corresponds to an atomically abrupt transition between covalently bonded Ga and metallic bonded Au.
Optical characteristics of arsenic-doped ZnO nanowires
Authors: Lee Woong , Jeong Min-Chang , Myoung Jae-Min
Published: December 2004

The effect of arsenic doping on optical characteristics of ZnO nanowires was investigated by photoluminescence spectroscopy carried out at 13–290K. In as-grown nanowires, emission due to acceptor-bound excitons predominated at low temperatures; as temperatures increased, emission due to recombination of free excitons prevailed. Arsenic-doped nanowires exhibited emission due to acceptor-bound excitons with no free exciton emission in the whole temperature range, indicating the formation of the acceptor level within the ZnO nanowire by arsenic doping.
X-ray laser-induced photoelectron spectroscopy for single-state measurements
Authors: Nelson A. J. , Dunn J. , van Buuren T. , Hunter J.
Published: December 2004

We demonstrate single-shot x-ray laser-induced time-of-flight photoelectron spectroscopy on metal and semiconductor surfaces with picosecond time resolution. Our compact multipulse terawatt tabletop x-ray laser source provides the necessary high photon flux (>1012∕pulse), monochromaticity, picosecond pulse duration, and coherence for probing ultrafast changes in the chemical and electronic structure of these materials. Static valence band and shallow core-level photoemission spectra are presented for ambient temperature polycrystalline Cu foils and Ge(100). Surface contamination was removed by UV ozone cleaning prior to analysis. The ultrafast nature of this technique lends itself to true single-state measurements of shocked and heated materials.
108 THE ROLE OF NITRIC OXIDE SYNTHASE IN IN VITRO DEVELOPMENT OF BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS
Authors: Kadanga A.K. , Tesfaye D. , Ponsuksili S. , Wimmers K. , Gilles M. , Schellander K.
Published: December 2004

Nitric oxide (NO) is a free radical that serves as a key-signal molecule in various physiological processes including reproduction. Four isoforms of nitric oxide synthase (NOS) have been characterized: endothelial (eNOS), inducible (iNOS), neuronal (nNOS), and mitochondrial (mtNOS). The first two isoforms are reported to be expressed in mouse follicles, oocytes, and pre-implantation embryos (Nishikimi A et al. 2001 Reproduction 122, 957–963). However, the role of any of these isoforms have not yet been investigated in bovine embryos. Here we aimed to examine the role of NOS in in vitro development of bovine embryos by treating embryos with NOS inhibitor, N-omega-L-nitro-arginine methyl esther (L-NAME), and examining the localization of the protein in pre-implantation embryos. Oocytes and embryos were grown in the media with NOS inhibitor added at a level of 0 mM (control), 1 mM, and 10 mM to either maturation or culture medium. Each experiment was conducted in four replicates each containing 100 oocytes for IVP. Cleavage and blastocyst rate were recorded at Days 2 and 7, respectively. Data were analyzed using the General Linear Model in SAS version 8.02 (SAS Institute, Inc., Cary, NC, USA) with the main factors being the level of L-NAME and the point of application. Pairwise comparisons were done using the Tukey test. Protein localization in bovine oocytes and embryos was performed by immunocytochemistry using eNOS- and iNOS-specific antibodies. Embryos were fixed in 3.7% paraformaldehyde, permeabilized in 0.1% Triton-X100, and washed three times in PBS supplemented with BSA. They were incubated with eNOS and iNOS primary antibody (1:200 dilutions) and washed before incubation with secondary antibody conjugated to FITC. After washing they were mounted on glass slides and examined under a confocal laser scanning microscope (Carl Zeiss Jena, Carl Zeiss AG, Oberkochen, Germany). In the controls the primary antibodies were omitted. As shown in the table below, the presence of L-NAME in the maturation medium significantly reduced the cleavage and blastocyst rate independent of the dosage applied. However the presence of L-NAME in the culture medium had an influence only on the blastocyst rate. The immunocytochemical staining results showed that both eNOS and iNOS are expressed in the cytoplasm of the MII oocytes, and during the pre-implantation stage the fluorescence signal was observed in nuclei and cytoplasm. However, the nuclear signal was much weaker. In conclusion, the present study is the first to determine the role of NO and to detect NOS protein in bovine oocytes and pre-implantation embryos. These results indicate that nitric oxide may play an important role as diffusible regulator of bovine oocyte maturation and preimplantation embryo development.

Table 1.
Effect of l-name addition in maturation or culture medium on embryo development
167 ISOLATION AND COMPARATIVE PROFILING OF HUMAN ADIPOSE-DERIVED ADULT STEM CELLS
Authors: Boquest A. , Shahdadfar A. , Fronsdal K. , Brinchmann J. , Collas P.
Published: December 2004

The stromal compartment of mesenchymal tissues is thought to harbor stem cells that display extensive proliferative capacity and multilineage potential. However, despite their potential impact in the field of regenerative medicine, little is known about the biology of stromal stem cells prior to culture. After removing adipocytes and erythrocytes from collagenase digested human adipose tissue, we identified two cell populations using flow cytometry which shared expression of stem cell markers SH2 and CD34, but lacked the phenotypic characteristics of leukocytes (CD45−). However, they were found to be discernible based on CD31 expression, a marker for endothelial cells. Using CD31 conjugated magnetic beads, we separated these cells (CD45-CD31− and CD45-CD31+) from three patients and compared global gene expression profiles using an Affymetrix platform. The prominant feature of CD45-CD31+ cells was the up-regulation of genes associated with endothelial cells. By contrast, CD45-CD31− cells were found to overexpress transcripts involved in cell cycle quiescence and cell signaling elements including those of the WNT pathway thought to be important for maintaining the stem cell state. Upon culture in DMEM/F12 with 20% FCS, only CD45-CD31− cells were capable of adhering to plastic and forming colonies. These cells with fibroblastic morphology met the key criterion of stem cells, the ability to proliferate while retaining the capacity to differentiate into mature tissues. Under appropriate inductive conditions, they were found to exclusively form bone, cartilage, adipose and neuronal-like tissues in vitro. Clonal cell lines generated from individually cultured CD45-CD31− cells displayed multilineage and proliferative capacity, validating our conclusion that they are true stem cells and not simply committed progenitors. We then undertook extensive comparative profiling of CD45-CD31− cells with their cultured counterparts to examine changes that stromal stem cells undergo during culture. Except for the disappearance of CD34, flow cytometry analysis using 52 antibodies revealed little change in cell surface phenotype as a result of culture. However, comparative global gene profiling revealed extensive down-regulation of many genes during culture. These included cell cycle arresting genes, as expected, and genes encoding elements involved in cell signaling including those belonging to the tumor necrosis factor, interleukin, transforming growth factor and chemokine families. The consequences of these changes remain unknown, but ultimately may affect the potential use of adipose tissue stem cells in regenerative medicine.
206 FOLLICULAR GROWTH SUBSEQUENT TO FOLLICULAR ASPIRATION IN THE MARE
Authors: Holbech L.N. , Frederiksen K.D. , Pedersen H.G. , Greve T. , Bøgh I.B.
Published: December 2004

Follicle aspiration has previously been used in mares as a research tool to remove growing and atretic follicles, in order to study follicular growth. The aim of the present study was to (1) evaluate the fate of the aspirated follicles, and (2) determine the point of selection of the dominant follicle subsequent to follicular aspiration. In six Standardbred mares, all follicles larger than 9 mm were removed by transvaginal ultrasound-guided aspiration (Day 0). Subsequent to follicular aspiration, the growth of follicles larger than 1 mm was monitored daily by ultrasonography from Day 0 to Day 7. Aspirated follicles were monitored to establish whether they refilled and continued to grow, or luteinized. The experiment was conducted in six replicates in each mare. On Day 1 after aspiration the largest and second largest follicles were 10.4 ± 0.8 mm (mean ± SEM) and 7.8 ± 0.6 mm, respectively. On Day 7 the largest follicle and the second largest follicle were 25.7 ± 1.2 mm and 18.6 ± 1.2 mm, respectively. In 10/209 follicles, the follicular cavity refilled subsequent to aspiration with non-echogenic fluid and the follicle diameter increased during the following 7 days. Four of the ten aspirated and refilled follicles grew to become the largest follicles, whereas the remaining six follicles did not reach dominance. A further three aspirated follicles grew and ovulated on Day 5. In one case, an aspirated follicle refilled and continued to grow after an oocyte had been recovered. However, from these preliminary results, the growth pattern of the aspirated follicle can not be predicted on the basis of whether or not the oocyte was removed during the aspiration session. Preliminary results of this study indicate that follicular selection for dominance as determined by follicular size difference may already have occurred on Day 1 after aspiration. Furthermore, follicles that refill with fluid and continue to grow after aspiration may pose a problem when follicular growth and selection are studied.
This research was funded by the Danish Research Agency, project no. 23-02-0133.
238 ASSESSMENT OF SPERM MOTILITY, VIABILITY, AND FERTILIZATION RATE OF TWO GROUPS OF BULLS SHOWING A DIFFERENT ABILITY TO PROMOTE EMBRYO DEVELOPMENT IN VITRO
Authors: Alomar M. , Mahieu J. , Verhaeghe B. , Donnay I.
Published: December 2004

Low developmental rates after IVF with some AI bulls are one of the most frequent problems encountered with in vitro production of bovine embryos. In this study, two groups of high and low in vitro fertility bulls (3 bulls per group) were selected based upon blastocyst rates. We first evaluated sperm motion characteristics using computer-assisted sperm analysis (CASA) before and after Percoll separation. The following parameters were compared between bulls: proportion of motile sperm (% MOT), curvilinear velocity (VCL), and straightness (STR), which allowed us to evaluate the proportion of progressive semen (VCL > 80 μm/s and STR > 60%). Concerning % MOT, differences between bulls were observed before Percoll separation (42 to 59% – ANOVA2: P = 0.017). Following separation, the values of % MOT were globally increased (ANOVA3: P < 0.001) and no further difference was observed between bulls (68 to 76%). The same pattern was obtained for the proportion of progressive spermatozoa (before: 43 to 55% vs. after: 48 to 57% – ANOVA3: P = 0.005). For viability measurements, two DNA-binding fluorochromes, propidium iodide and Hoechst 33342, were used, which respectively stain dead sperm nuclei in red and living sperm nuclei in blue. This viability evaluation was carried out after 0, 2, 6, and 18 h of incubation in TALP medium supplemented with heparin (10 μg/mL), under the same conditions as IVF but without oocytes. In the two groups of bulls, a sharp decrease in the proportion of living sperm was already observed at 2 h (only 50 to 20% of living sperm), while, at 18 h, 17 to 9% of sperm were still intact. Two bulls from the high in vitro fertility group showed a percentage of living sperm significantly more important at 6 and 18 h than the other 4 bulls (chi square – P < 0.05). In a third experiment, we assessed the fertilization (2 pronuclei) and the polyspermy (>2 pronuclei) rates after staining the zygotes with Hoechst at 18 hpi. The high fertility group showed higher fertilization rates than the low fertility one (75 to 80% vs. 59 to 67% – ANOVA2: P < 0.008). No significant difference was noticed between bulls concerning polyspermy. The present results confirm the efficiency of Percoll separation in enhancing some of the motility parameters such as the proportion of motile and progressive sperm. Moreover, this gradient allows us to abolish differences between bulls for those motility parameters. However, the viability and the rate of fertilization still varied between bulls after Percoll separation. In our study, only fertilization rates seemed related to the blastocyst rates. Further investigations are under way to better understand the sperm characteristics of these two groups.
This work was supported by the Minestery of Agriculture of the Region wallonne de Belgique.
254 EFFECT OF FSH TREATMENT ON NUMBER OF BOVINE OOCYTES RETRIEVED BY NON-ULTRASOUND GUIDED TRANSVAGINAL OVUM PICK-UP AND THEIR DEVELOPMENTAL COMPETENCE
Authors: Sathanawongs A. , Rojanasthien S. , Oranratnachai A. , Sumretprasong J.
Published: December 2004

This study was conducted to investigate the efficacy of FSH stimulation on the number of bovine oocytes retrieved by non-ultrasound-guided transvaginal ovum pickup and their developmental competence. In Experiment 1, to study the effect of FSH treatment on meiotic maturation, oocyte donors were divided into two groups (n = 5/group). Group I received no FSH treatment and aspiration was performed twice weekly, whereas Group II received 200 mg FSH (Folltropin-V) treatment twice daily for 3 days prior to aspiration, which was performed once every two weeks. Both groups were investigated for 8 weeks, after which crossover treatment continued for another 8 weeks. The retrieved oocytes were cultured for 24 h in vitro, and the chromosomal stages were evaluated by staining with 1% aceto-orcein. Experiment 2 was designed to determine the effect of FSH treatment on developmental competence of bovine oocytes. Oocytes were obtained from FSH-treated and untreated control cows (n = 3/group), and they were matured, fertilized, and cultured in vitro. The results showed that Group II females had a higher number of retrieved oocytes per cow per session than Group I females (7.05 ± 3.88 vs. 2.06 ± 0.99, respectively; P < 0.05). The FSH stimulation led to an increase in the proportion of matured oocytes (69.6% vs. 63.3%) and also increased the percentage of cleavage stage embryos (49.4% vs. 32.2%) compared with untreated control cows (P < 0.05). However, there was no difference between the two groups in percentage of morula and blastocyst formation (11.1%, 8.6% and 10.2%, 6.8%, respectively). In conclusion, the combination of non-ultrasound-guided transvaginal ovum pickup with FSH stimulation increased the number of retrieved oocytes per cow per session and tended to increase in vitro embryo production.
The authors gratefully acknowledge the support by the Chiang Mai Artificial Insemination Center, Thailand.