bluuebunny/crossref_metadata_2025 huggingface dataset:
Photo‐oxidation of lipids impregnated on the surface of dried seaweed (Porphyra yezoensis Ueda). Hydroperoxide distribution
Authors: Pan Xiangqing , Ushio Hideki , Ohshima Toshiaki
Published: November 2006

The distribution of hydroperoxide isomers generated by photo‐oxidation of natural lipids impregnated on the surface of dried seaweed previously exposed to visible light and without added photosensitizer were studied. The surface of dried seaweed was impregnated with linoleic acid methyl ester, and the sample was divided into two parts. One part was exposed to light from a 100‐W tungsten bulb (4500 lux) in a low‐temperature room (5°C). The other part was kept in the dark as a control. Positional isomers of the hydroperoxides generated from the impregnated linoleic acid methyl ester were separated individually by HPLC and further identified by MS. The dried seaweed kept in the dark contained four hydroperoxide isomers, namely, 13‐hydroperoxy‐cis‐9, trans‐11‐octadecadienoate, 13‐hydroperoxy‐trans‐9, trans‐11‐octadecadienoate, 9‐hydroperoxy‐trans‐10,cis‐12‐octadecadienoate, and 9‐hydroperoxy‐trans‐10, trans‐12‐octadecadienoate. For the dried seaweed exposed to light, the oxidized lipids contained not only the same four isomers, but also 12‐hydroperoxy‐cis‐9, trans‐13‐octadecadienoate and 10‐hydroperoxy‐trans‐8,cis‐12‐octadecadienoate. When fresh seaweed was dried in the sunlight, the formation of 12‐cis,trans‐ and 10‐cis,trans‐hydroperoxides of naturally occurring methyl linoleate was verified. Dried seaweed was then impregnated with eicosapentaenoic acid ethyl ester and exposed to light. Light exposure also generated certain hydroperoxide isomers attributable to singlet oxygen oxidation, namely, 6‐hydroperoxy‐trans‐4,cis‐8, cis‐11,cis‐14,cis‐17‐ethyl and 17‐hydroperoxy‐cis‐5,cis‐8,cis‐11, cis‐14,trans‐18‐ethyl eicosapentaenoate. When dried sea‐weed without any impregnated lipids was exposed to the light for 24 h in a cold room (5°C), characteristic isomers, including both the 20‐carbon FA isomers 6‐OOH and 17‐OOH as well as the 18‐carbon FA isomers 10‐OOH and 12‐OOH, were detected in the light‐exposed sample but were not found in the control. These results clearly show that singlet oxygen oxidation of lipids occurred in the seaweed exposed to light. We concluded that this lipid oxidation was catalyzed by chlorophyll as a photosensitizer in seaweed.
Liquid‐phase theoretical antioxidant activity trend of some cinnamic acid antioxidants
Authors: Lithoxoidou Alexandra T. , Bakalbassis Evangelos G.
Published: November 2006

The trend in antioxidant activity of four cinnamic acid antioxidants, derived on the basis of their liquid‐phase phenolic O H bond dissociation enthalpies, is determined theoretically, with the aid of the polarizable continuum model at the density functional theory level. Three solvents, differing in their hydrogen‐bonding ability and polarity—n‐heptane, acetonitrile, and ethanol—were used to model different environmental situations. The trends in solution‐phase antioxidant activity appeared different in each solvent; still, the theoretical antioxidant activity trend derived in n‐heptane was in excellent agreement with the experimental one in the lipid systems and the gas‐phase system. Different ortho substituents show notably different solvent effects. These results could lead to the determination of reliable antioxidant activity trends in real‐solution environments of interest in food or biological science frameworks.
Utilization of olive‐residue oil in the formulation of lubricating calcium greases
Authors: Chtourou Manef , Trabelsi Mahmoud , Frikha Mohamed Hédi
Published: November 2006

Calcium greases were manufactured from olive‐residue oil in a closed reactor by substituting olive‐residue oil for animal tallow. The results of the performance tests applied to the obtained greases showed that their physicochemical and mechanical characteristics are comparable to those of calcium grease manufactured industrially by using animal tallow. The substitution of part of the animal tallow with olive‐residue oil increased the thermal and mechanical stability of the grease. Olive‐residue oil could constitute, alone or in combination with animal tallow, a raw material in the formulation of lubricating calcium grease.
Emulsifying properties and surface behavior of native and denatured whey soy proteins in comparison with other proteins. Creaming stability of oil‐in‐water emulsions
Authors: Palazolo Gonzalo G. , Sorgentini Delia A. , Wagner Jorge R.
Published: November 2006

In this work a comparative study of emulsifying and surface behaviors of native whey soy proteins (NWSP) and denatured whey soy proteins (DWSP) with those of native soy isolates, denatured soy isolates (DSI), and sodium caseinate was done. These samples showed different molecular mass distributions in gel filtration profiles. Dissociation and soluble high‐M.W. species in DWSP and DSI were observed. Lower interfacial and surface pressure values were obtained with native samples. Thermal treatment and salt addition enhanced tensioactivity in all fractions. Backscattering measurements of all oil‐in‐water emulsions, which exhibited a trimodal size distribution of droplets, showed the existence of a negative correlation with the median diameter of droplets. Greater droplet sizes were observed with NaCl addition. The NWSP emulsion had the lowest stability against creaming. Denaturation of this sample increased stability and favored air incorporation in emulsions. Destabilization depends not only on median droplet size but also on floc formation and structure. NaCl addition negatively affected the creaming stability only in emulsions formulated with soy isolates. The use of denaturation to enhance the surface and emulsifying properties of whey soy proteins would allow their use in food emulsions.
Production of linolenic acid in yeast cells expressing an omega‐3 desaturase from tung (Aleurites fordii)
Authors: Dyer John M. , Chapital Dorselyn C. , Kuan Jui‐Chang W. , Shepherd Hurley S. , Tang Fuqiang , Pepperman Armand B.
Published: November 2006

Tung oil is an industrial drying oil containing ca. 90% PUFA. We previously reported on enzymes required for the synthesis of linoleic (6% of FA) and eleostearic (80%) acids and here describe the cloning and functional analysis of an omega‐3 FA desaturase (FAD3) required for the synthesis of linolenic acid (1%). The tung FAD3 cDNA was identified by screening a tung seed cDNA library using the polymerase chain reaction and degenerate primers encoding conserved regions of the FAD3 enzyme family. Expression of this cDNA in yeast cells, cultured in the presence of linoleic acid, resulted in the synthesis and accumulation of linolenic acid, which accounted for up to 18% w/w of total cellular FA. Tung FAD3 activity was significantly affected by cultivation temperature, with the greatest amount of linolenic acid accumulating in yeast cells grown at 15°C. The amount of linolenic acid synthesized in yeast cells by tung FAD3 is ca. 10‐fold higher than that observed by expression of a rapeseed (Brassica napus) FAD3 in yeast, suggesting that tung FAD3 might be useful for biotechnological production of omega‐3 FA in transgenic organisms.
Production of monodispersed water‐in‐oil emulsions using polymer microchannels
Authors: Liu Haijie , Nakajima Mitsutoshi , Kimura Toshinori
Published: November 2006

Monodispersed water‐in‐oil (W/O) emulsions were prepared using new fabricated acrylic polymer microchannel (MC) plates. Acrylic plate MC‐A1 was 20 μm wide, 10 μm deep, and 120 μm long; and MC‐A2 was 40 μm wide, 20 μm deep, and 120 μm long with respect to MC sizes. Both MC plates had a terrace length of 30 μm. Monodispersed waterin‐triolein emulsions with average diameters of 42 to 60 μm (MC‐A1) and 62 to 98 μm (MC‐A2) were prepared successfully using tetraglycerin condensed ricinoleic acid ester (CR310) as a surfactant. The CV for droplets produced was less than 10%, demonstrating monodispersity. When we used decane (which is less viscous than triolein) as the continuous phase and CR310 and hexaglycerin pentaoleate (PO500) as surfactants, the average diameters and CV of the droplets became smaller, and the pressure ranges for stable droplet formation were much wider than for the water/triolein system. For comparison, a silicon MC plate (MC‐Si) with dimensions similar to the polymer MC‐A1 was tested and exhibited little significant difference in the average diameter and CV of droplets between MC‐A1 and MC‐Si.
Inguinale Schwellung: druckdolent, überwärmt
Authors: v. Orelli  , Hess
Published: November 2006

Bei dem 66-jährigen Patienten trat während der Rückreise aus Portugal zusätzlich zum bestehenden Perianalabszess eine grosse druckdolente Schwellung inguinal rechts auf. Nach Lymphonodektomie zum Ausschluss eines Malignoms wurde im Wundabstrich Nocardia brasiliensis isoliert und die Diagnose Nokardiose gestellt. Die Nokardiose sollte in der Differentialdiagnose von kutanen infektiösen Prozessen, insbesondere in Kombination mit einer Anamnese von Verletzungen im Freien, nicht fehlen. Die Diagnose wird mittels Kultur aus dem infizierten Gewebe gestellt. Die resistenzgerechte Behandlung mit Co-Trimoxazol für insgesamt zwei Monate in Kombination mit chirurgischer Sanierung des Perianalabszesses, resultierte in einer vollständigen Heilung der Infektion.
Analysis of ecosystem controls on soil carbon source‐sink relationships in the northwest Great Plains
Authors: Tan Zhengxi , Liu Shuguang , Johnston Carol A. , Liu Jinxun , Tieszen Larry L.
Published: November 2006

Our ability to forecast the role of ecosystem processes in mitigating global greenhouse effects relies on understanding the driving forces on terrestrial C dynamics. This study evaluated the controls on soil organic C (SOC) changes from 1973 to 2000 in the northwest Great Plains. SOC source‐sink relationships were quantified using the General Ensemble Biogeochemical Modeling System (GEMS) based on 40 randomly located 10 × 10 km2 sample blocks. These sample blocks were aggregated into cropland, grassland, and forestland groups based on land cover composition within each sample block. Canonical correlation analysis indicated that SOC source‐sink relationship from 1973 to 2000 was significantly related to the land cover type while the change rates mainly depended on the baseline SOC level and annual precipitation. Of all selected driving factors, the baseline SOC and nitrogen levels controlled the SOC change rates for the forestland and cropland groups, while annual precipitation determined the C source‐sink relationship for the grassland group in which noticeable SOC sink strength was attributed to the conversion from cropped area to grass cover. Canonical correlation analysis also showed that grassland ecosystems are more complicated than others in the ecoregion, which may be difficult to identify on a field scale. Current model simulations need further adjustments to the model input variables for the grass cover‐dominated ecosystems in the ecoregion.
On the turnaround of stratospheric ozone trends deduced from the reevaluated Umkehr record of Arosa, Switzerland
Authors: Zanis P. , Maillard E. , Staehelin J. , Zerefos C. , Kosmidis E. , Tourpali K. , Wohltmann I.
Published: November 2006

In this work, we investigate the issue of the turnaround in ozone trends of the recently homogenized Umkehr ozone record of Arosa, Switzerland, which is the longest Umkehr data set, extending from 1956 to date, using different statistical methods. All methods show statistically significant negative ozone trends from 1970 to 1995 in the upper stratosphere (above 32.6 km) throughout the course of the year as well as in the lower stratosphere (below 23.5 km) mainly during winter to spring, which can be partially attributed to dynamical changes. Over the recent period (1996–2004) the year‐round trends in the lower stratosphere become positive and are more positive during the winter to spring period. The results also show changes in upper stratospheric ozone trends after 1996, which are, however, not statistically significant at 95% if aerosol correction is applied on the retrieved data. This lack of significant trend changes during the recent period in the upper stratosphere is regionally coherent with recent results derived from upper stratospheric ozone data recorded by lidars, microwave radiometers, and satellite instruments at an adjacent location. Although the positive change in trends after 1996 both for upper and lower stratospheric ozone is in line with the reduction of the emissions of ozone‐depleting substances from the successful implementation of the Montreal Protocol and its amendments, we recommend, because of lack of significance for the upper stratospheric trends, repeating this analysis in a few years in order to overcome ambiguous results for documentation of the turnaround of upper stratospheric ozone.
Increased Eurasian‐tropical temperature amplitude difference in recent centuries: Implications for the Asian monsoon
Authors: D'Arrigo Rosanne , Wilson Rob , Li Jinbao
Published: November 2006

A warmer Eurasian continent and stronger land/sea temperature gradient between Eurasia and the tropical oceans contribute to an intensified summer monsoon. We evaluate changes in the temperature difference between Eurasia and the tropics over 250 years using proxies of Eurasian surface air temperatures (tree rings) and tropical sea surface temperatures (Indo‐Pacific corals). These records show low‐frequency correspondence with each other over this interval, and with other temperature and precipitation‐sensitive proxies from the Asian monsoon regime. Greater warming is estimated for Eurasia (amplitude = 1.70 ± 0.28°C; 1801–20 vs 1976–95) relative to the tropics (0.61 ± 0.29°C; 1806–25 vs 1937–56). The amplitude change from the 18th to 20th centuries is thus estimated to be about three times (1.5–6) greater over Eurasia than the tropics. This change may have contributed to an intensified Asian monsoon system over recent centuries, and to a decoupling of the monsoon and El Niño‐Southern Oscillation in recent decades.
Core region of Arctic Oscillation and the main atmospheric events impact on the Arctic
Authors: Zhao Jinping , Cao Yong , Shi Jiuxin
Published: November 2006

Arctic Oscillation (AO) is a seesaw pattern in which sea level pressure (SLP) at the polar and middle latitudes in North Hemisphere fluctuates between positive and negative phases. It has been used as a representative atmospheric circulation index to express climate change. The purpose of this paper is to reveal the regional difference of SLP variation. By calculating the correlation coefficients of AO Index with all the gridded SLPs, we have uncovered a special region named as Arctic Oscillation Core Region (AOCR), where the running correlation coefficients (RCC) between gridded SLP and AO index are all negative. The averaged SLP of this region correlates significantly with the AO index. The correlations between local SLPs and AO index outside of AOCR are weaker than those inside. RCC analysis reveals several strong discrepant events different from AO. These events occurred in the years of 1954, 1955, 1962, 1971, 1982/83, 1995, 1996/97, 1998, and 1999. A comparison of these events and the ENSO or PDO indices suggests that the events in 1982/83 and 1998 are probably associated with the ENSO processes. Events centered in other years are likely connected with PDO, which reached their minima in the years of 1950, 1955, 1962 and 1971. The result in this study provides an alternative insight to look at the mechanism of the variation of Arctic Oscillation.
Evaluation of the Second Global Soil Wetness Project soil moisture simulations: 1. Intermodel comparison
Authors: Guo Zhichang , Dirmeyer Paul A.
Published: November 2006

Driven with the meteorological data sets based on the reanalyses and gridded observational data archived by the International Satellite Land‐Surface Climatology Project (ISLSCP) Initiative II, eleven different land surface models generated global soil moisture data sets for the 10‐year period (1986–1995) for the Second Global Soil Wetness Project (GSWP‐2). We evaluate these model simulations against in situ observations over grasslands and agricultural regions in the former Soviet Union, United States (Illinois), China, and Mongolia from the Global Soil Moisture Data Bank in terms of their ability to estimate the actual column plant‐available soil moisture in the top 1‐m soil layer, to simulate the phasing of the annual cycle, and to represent observed interannual variability. Results from these 11 land surface models show that they reproduce reasonably well the observed interannual variability and phasing of the annual cycle. Statistical analysis also shows that the median root mean square of errors among these models ranges from 4 to 8 cm of soil moisture. Similar to what has been found in soil moisture simulations for GSWP‐1, the absolute values of soil moisture are poorly simulated by most models. However, the models do a good job of reproducing the soil moisture anomalies. This suggests that the global soil wetness data set produced by GSWP‐2 can be used for analyzing climate variability and initializing GCMs by using transform strategies. This also has relevance to subseasonal to seasonal forecasts since soil moisture anomalies may potentially have impact on precipitation.
Ponderomotive acceleration of injected electrons in tenuous plasmas by intense laser pulses
Authors: Sazegari V. , Shokri B.
Published: November 2006

The trapping and acceleration of an electron by forward ponderomotive force associated with intense short laser pulses, propagating in homogeneous rarefied plasmas is analyzed. This is done not by solving the motion equations but by energy conservation law and Lorentz transformation. This method is able to the treat the ponderomotive acceleration regardless of laser polarization. It is shown that the gain of acceleration increases linearly with the field strength of the laser and the relativistic factor of the group velocity of the laser in the plasma, while the minimum injection energy necessary for trapping the electron decreases with the laser field strength and increases slowly with the group velocity of the laser.
Characterization of the behavior of chemically reactive species in a nonequilibrium inductively coupled argon-hydrogen thermal plasma under pulse-modulated operation
Authors: Ye Rubin , Ishigaki Takamasa , Taguchi Hiroyuki , Ito Shigeru , Murphy Anthony B. , Lange Hubert
Published: November 2006

The temporal and spatial dependence of species densities in a pulse-modulated inductively coupled plasma (PM-ICP) in an argon-hydrogen mixture was investigated by means of numerical modeling, taking into account time dependence, two temperatures, and chemical nonequilibrium, and also through spectroscopic measurements. Conservation equations for mass, momentum, electron energy, heavy-species energy, each species, and the electromagnetic field were developed and solved self-consistently. The transient behavior of the mass fraction of each species was determined by including chemical kinetics source terms in the species conservation equations. Fourteen chemical reactions involving seven species (e, Ar, Ar+, H2, H2+, H, and H+) were considered. The transport properties were evaluated based on the local species densities using the first-order approximation of the Chapman-Enskog method. Time-resolved electron density profiles were obtained from measurements of the Stark broadening of the Hβ line (486.1nm), performed using an optical system positioned using a stepper motor. The investigations were conducted for a maximum power level of 11.7kW with a duty factor of 66.7% and at a pressure of 27kPa. Reasonable agreement was found between the predicted and measured electron densities. The electron density in the discharge region varied considerably over a pulse cycle, while the hydrogen atom density remained high throughout the cycle, and peaked in a region that has been experimentally demonstrated to have optimal efficiency for hydrogen doping of materials. The main mechanisms responsible for the production of the relevant species in the PM-ICP are discussed.
An experimental and theoretical study of double photoionization of CF4 using time-of-flight photoelectron-photoelectron (photoion-photoion) coincidence spectroscopy
Authors: Feifel R. , Eland J. H. D. , Storchi L. , Tarantelli F.
Published: November 2006

Single photon double ionization of CF4 has been studied by means of a time-of-flight photoelectron-photoelectron coincidence technique, which has very recently been extended towards ion detection, with energy analysis for the electrons and mass analysis for the ions. The complete single photon double ionization electron spectrum of CF4 up to a binding energy of ∼51eV is presented and discussed, also with the aid of accurate ab initio Green’s function calculations. From ion detection in coincidence with the ejected electrons, we derive fragmentation pathway-selected double ionization electron spectra of CF4. From the same data we extract the yield of each doubly charged ion or ion pair as a function of the double ionization energy.
Frequency dispersion of hysteresis in uniaxially anisotropic Heisenberg model: Spin-tilting resonance
Authors: Chen X. , Guo Y. B. , Yu H. , Liu J.-M.
Published: November 2006

The frequency dispersion of magnetic hysteresis for uniaxially anisotropic Heisenberg model in two-dimensional square lattice is studied by Monte Carlo simulation and mean-field calculation in order to investigate the high frequency spin-tilting resonance. It is observed that besides the spin reversal resonance which usually occurs under ac magnetic field of low frequency and high amplitude, the hysteresis dispersion may exhibit a second peak which occurs in the regime of high frequency and low amplitude and depends on the uniaxial anisotropy. It is argued that the second peak originates from the spin tilting in resonance with the ac magnetic field, which generates hysteresis far from saturation and is essentially different from the spin reversal resonance peak. The high frequency power-law scaling of the hysteresis is demonstrated for both the spin reversal mode and spin-tilting mode.
Entropy, diffusivity, and structural order in liquids with waterlike anomalies
Authors: Sharma Ruchi , Chakraborty Somendra Nath , Chakravarty Charusita
Published: November 2006

The excess entropy, defined as the difference between the entropies of the liquid and the ideal gas under identical density and temperature conditions, is studied as a function of density and temperature for liquid silica and a two-scale ramp potential, both of which are known to possess waterlike liquid state anomalies. The excess entropy for both systems is evaluated using a fairly accurate pair correlation approximation. The connection between the excess entropy and the density and diffusional anomalies is demonstrated. Using the pair correlation approximation to the excess entropy, it can be shown that if the energetically favorable local geometries in the low and high density limits have different symmetries, then a structurally anomalous regime can be defined in terms of orientational and translational order parameters, as in the case of silica and the two-scale ramp system but not for the one-scale ramp liquid. Within the category of liquids with waterlike anomalies, we show that the relationship between the macroscopic entropy and internal energy is sufficient to distinguish between those with local anisotropy and consequent open packings at low densities and those with isotropic interactions but multiple length scales. Since it is straightforward to evaluate the pair correlation entropy and internal energy from simulations or experimental data, such plots should provide a convenient means to diagnose the existence as well as type of anomalous behavior in a range of liquids, including ionic and intermetallic melts and complex fluids with ultrasoft repulsions.
Cascaded active regions in 2.4μm GaInAsSb light-emitting diodes for improved current efficiency
Authors: Prineas J. P. , Olesberg J. T. , Yager J. R. , Cao C. , Coretsopoulos C. , Reddy M. H. M.
Published: November 2006

By cascading multiple GaInAsSb active regions, the authors have fabricated 2.4μm light-emitting diodes that, for a given light output, operate at reduced current and higher voltage, which can be advantageous for battery-powered sensor applications. Tunnel heterojunctions separating emission regions add no measurable series resistance. Devices are demonstrated at room temperature with continuous wave output.
Copper (II) oxide as a giant dielectric material
Authors: Sarkar Sudipta , Jana Pradip Kumar , Chaudhuri B. K. , Sakata H.
Published: November 2006

Bulk copper (II) oxide (CuO), heat treated at 1223K, shows extraordinarily high dielectric constant (εr∼104), almost independent of temperature (above 230K) and frequency in the kilohertz region. A sudden decrease of εr is observed at lower temperature (below 150K). X-ray photoelectron spectroscopy and high resolution transmission electron microscopy studies confirm the presence of a microscopic amount of Cu3+ in annealed CuO. The dielectric behavior of CuO can be explained by Maxwell-Wagner-type polarization mechanism and thermally activated mechanism.
The dependence of electrostatic solvation energy on dielectric constants in Poisson-Boltzmann calculations
Authors: Tjong Harianto , Zhou Huang-Xiang
Published: November 2006

The Poisson-Boltzmann equation gives the electrostatic free energy of a solute molecule (with dielectric constant εl) solvated in a continuum solvent (with dielectric constant εs). Here a simple formula is presented that accurately predicts the electrostatic free energy for all combinations of εl and εs from the calculation on a single set of εl and εs values.
Nonlinear analysis of periodic modulation in resonances of cylindrical and spherical acoustic standing waves
Authors: Kurihara Eru , Yano Takeru
Published: November 2006

The nonlinear resonance of cylindrical acoustic standing waves of an ideal gas contained between two coaxial cylinders is theoretically investigated by the method of multiple scales. The wave motion concerned is excited by a small-amplitude harmonic oscillation of the radius of the outer cylinder, and the formulation of the problem includes the wave phenomenon in a hollow cylinder without the inner one as a limiting case. The spherical standing wave in two concentric spheres is also studied in parallel. The resonance occurs if the driving frequency falls in a narrow band around the linear resonance frequency, and in the weakly nonlinear regime, no shock wave is formed in contrast to the plane wave resonance. A cubic nonlinear equation for complex wave amplitude can then be derived by the method of multiple scales. Using a first integral of the cubic nonlinear equation, we shall demonstrate that the resonant oscillation is accompanied by a periodic modulation of amplitude and phase when the dissipation effect due to viscosity and thermal conductivity is negligible. The period of the modulation varies as the minus two-thirds power of the acoustic Mach number defined at the outer cylinder or sphere and decreases with an increase in the radius ratio of the inner and outer cylinders or spheres. When the dissipation effect is small but not negligible, the modulation is slowly weakened and the resonant oscillation approaches a steady state oscillation, which corresponds to the steady solution examined in earlier works.
Grain boundary weak link in a-b plane in MgB2 film
Authors: Stepantsov E. , Tarasov M. , Naito M. , Tsukada A. , Winkler D.
Published: November 2006

The authors have fabricated the MgB2 bridges 850–6000nm in width on bicrystal (111) MgO substrates with in-plane grain boundaries of the two types: 13°∕13° ⟨110⟩ and 13°∕13° ⟨112⟩. Annealing in oxygen of the films on ⟨110⟩ bicrystal substrates leads to a systematic decrease of critical current, a widening of the transition temperature width, and an improvement of the shape of IV curve that finally looks more like a Josephson junction. They have measured a response of such samples to the microwave radiation at 110GHz with the voltage amplitude up to 0.5mV.
Coulomb scattering in the Monte Carlo simulation of terahertz quantum-cascade lasers
Authors: Lü J. T. , Cao J. C.
Published: November 2006

The authors compare different Coulomb screening models in the Monte Carlo simulation of terahertz quantum-cascade lasers: the static multisubband screening model and two single subband models. In quantum-cascade structures, electrons are located in many different subbands. Coulomb screening from all these subbands influences the intra- and intersubband scattering processes. The simulation results show that one of the two single subband models overestimates the screening effect, while the other underestimates it. The authors show the reasons for this and propose simple modification to the single subband models.
High- and low-spin complexes with similar, ligands. II. Iron(II) complexes with sterically hindered analogues of 2,2'-bipyridyl
Authors: Harris CM , Kokot S , Patil HRH , Sinn E , Wong H
Published: November 2006

Benzo substitution cis to the nitrogen of 2,2'-bipyridyl (bipy), to form 2-(2'-pyridyl)quinoline
(pq), transforms the tris-complex with iron(11) from
low spin in Fe(bipy)32+ to
essentially high spin but near the crossover in Fe(pq)32+.
For this complex, the ligand field splitting near the crossover, Δc is estimated from magnetic and spectral
data as c. 12000 cm-l. A similar value but 150 cm-l lower
is estimated for the analogous complex with the sterically related ligand
2-methyl-1,10-phenanthroline. This apparent difference in Δ values could
arise from a direct change in ligand field potential, or from other factors,
such as a change in distortion effects. Due to steric hindrance, pq prefers to form bis-complexes Fe(pq)2X2,
pseudooctahedral and high spin, with suitable monodentates, X = Cl2 Br, NCS, ClO4. Double benzo substitution of bipy to form 2,2'-biquinolyl (biq)
so increases steric hindrance that the tris-complex could not be formed.
Instead biq forms pseudotetrahedral
complexes Fe(biq)22+ and Fe(biq)X2 (X = Cl, Br).
Acridone studies. XI. Reaction of some Polyalkoxy-10-methylacridones with sodium methoxide in methanol and in dimethyl sulphoxide
Authors: Hodgeman DKC , Prager RH
Published: November 2006

The isomeric
dimethoxymethylenedioxy-10-methylacridone react with sodium methoxide in
methanol to give a number of products which have been characterized.
Substitution occurs on both the aromatic nucleus and the methylene group. In
dimethyl sulphoxide opening of the methylenedioxy ring occurs exclusively and the rates and
activation parameters of this reaction have been measured.
No transuterine migration of fertilised ova after unilateral embryo transfer in mice
Authors: Rülicke Thomas , Haenggli Amy , Rappold Kirsten , Moehrlen Ueli , Stallmach Thomas
Published: November 2006

Transuterine migration is the passage of fertilised ova from one uterine horn into the other. The phenomenon has been described for animals of different species with a bicornuate type of uterus. Whether or not it occurs in rodents is questionable, but could have an impact on the way embryo transfers are carried out, i.e. unilaterally or bilaterally. The aim of this study was to examine the occurrence of transuterine migrations in nulliparous and multiparous mice after unilateral embryo transfer. Sixteen two-cell embryos were transferred into either the left or the right oviduct of mice with different genetic origin. With the exception of one reabsorption site in the opposite uterine horn, we never found evidence for the occurrence of transuterine migration. This is also true for embryo transfers carried out after parturition of the surrogate mother. Even the successful development of up to 13 embryos in one uterine horn did not result in transmigration but may be the reason for the widespread assumption that transuterine migration occurs after unilateral embryo transfers. The separation of the uterine body and the prevaginal portion of the uterine cervix into two canals by a septum seems to be the main reason for the absence of successful transuterine migration in mice.
Human embryonic stem cells: challenges and opportunities
Authors: Stice Steven L. , Boyd Nolan L. , Dhara Sujoy K. , Gerwe Brian A. , Machacek David W. , Shin Soojung
Published: November 2006

Human and non-human primate embryonic stem (ES) cells are invaluable resources for developmental studies, pharmaceutical research and a better understanding of human disease and replacement therapies. In 1998, subsequent to the establishment of the first monkey ES cell line in 1995, the first human ES cell line was developed. Later, three of the National Institute of Health (NIH) lines (BG01, BG02 and BG03) were derived from embryos that would have been discarded because of their poor quality. A major challenge to research in this area is maintaining the unique characteristics and a normal karyotype in the NIH-registered human ES cell lines. A normal karyotype can be maintained under certain culture conditions. In addition, a major goal in stem cell research is to direct ES cells towards a limited cell fate, with research progressing towards the derivation of a variety of cell types. We and others have built on findings in vertebrate (frog, chicken and mouse) neural development and from mouse ES cell research to derive neural stem cells from human ES cells. We have directed these derived human neural stem cells to differentiate into motoneurons using a combination of developmental cues (growth factors) that are spatially and temporally defined. These and other human ES cell derivatives will be used to screen new compounds and develop innovative cell therapies for degenerative diseases.
Identifying novel substrates for mouse Cdk5 kinase using the yeast Saccharomyces cerevisiae
Authors: Horiuchi Youko , Asada Akiko , Hisanaga Shin‐ichi , Toh‐e Akio , Nishizawa Masafumi
Published: November 2006

Among the mammalian Cdk family members, Cdk5, activated by the binding of p35, plays an important role in the control of neurogenesis, and its deregulation is thought to be one of the causes of neurodegenerative diseases. Overproduction of Cdk5 and p35 in yeast cells causes growth arrest, probably because of hyperphosphorylation of yeast proteins. We screened mouse brain cDNA that could recover the growth of yeast cells overproducing Cdk5 and p35, hoping that such cDNA encodes a substrate or inhibitor of Cdk5. Mouse brain cDNA library was introduced into a yeast strain in which Cdk5, p35 and mouse cDNA were over‐expressed under the control of the GAL promoter, and cDNA plasmids were isolated from the transformants that recovered growth on galactose medium. The analysis of those plasmids revealed that they harbored cDNA that encodes neuronal proteins including SCLIP and CRMP‐1, and those with unknown function. We found that Cdk5 could phosphorylate SCLIP and CRMP‐1 in vitro and the two proteins in cultured cells showed a mobility shift depending on Cdk5 activity and the presence of specific Ser or Thr residues, indicating that SCLIP and CRMP‐1 are likely substrates for Cdk5 in vitro and in cultured cells. Further screening with these systems will enable us to identify more novel substrates and regulators of Cdk5/p35, which will lead to the exploration of Cdk5 function in diverse cellular systems.
Effects of perfluorochemical evaporative properties on oxygenation during partial liquid ventilation
Authors: JENG MEI‐JY , YANG SHYH‐SHENG , HWANG BETAU , WOLFSON MARLA R. , SHAFFER THOMAS H.
Published: November 2006

Background:  The physical‐chemical properties of perfluorochemical (PFC) liquids have been shown to influence physiological and cellular responses during partial liquid ventilation (PLV). The aim of this study is to compare the relationship between patho‐physiological endpoints and the physical properties of three PFC liquids used in treating acute lung injury.

Methods:  A total of 18 juvenile rabbits were randomized into conventional mechanical ventilation or PLV groups after lung saline lavages. Three PFC liquids, including Flutec perfluoro‐1,3,5‐trimethylcyclohexane (PP4; vapor pressure, 28.8 mmHg at 37°C), Perfluorodecalin (PFD; vapor pressure, 13.6 mmHg at 37°C), and Perflubron (PFB; vapor pressure, 10.4 mmHg at 37°C) were used for PLV with no replacement for 4 h. A thermal detector was used to measure PFC loss rate. Physiological measurements and evaporative loss rate of PFC were done every 30 min, and lung histology was examined.

Results:  The mean evaporative loss rate was significantly higher in the PP4 group (4.75 ± 0.24 mL/kg per h) than in either the PFD (1.43 ± 0.11 mL/kg per h) or the PFB (1.18 ± 0.05 mL/kg per h) group (P < 0.05). The oxygenation of PFD and PFB was maintained good for 4 h, however, the PP4 group showed a fast deterioration since 2 h post‐treatment due to fast dropping of the residual PP4 amount in lungs. Histology showed good alveolar integrity in the PFD and PFB groups.

Conclusions:  The effects of PLV are directly influenced by the evaporative property of the PFC liquid. With no replacement over 4 h, PLV effects could be maintained with utilizing a PFC liquid with low, rather than high, vapor pressure. PFC with high vapor pressure has a high loss rate and low residual volume that causes poor maintenance on oxygenation during PLV. Therefore, measuring PFC loss rate is important in future studies and clinical application of PLV.
Study of 24 cases with congenital esophageal atresia: What are the risk factors?
Authors: SUGITO KIMINOBU , KOSHINAGA TSUGUMICHI , HOSHINO MAYUMI , INOUE MIKIYA , GOTO HIROSHI , IKEDA TARO , HAGIWARA NORITSUGU
Published: November 2006

Background: Recovery from esophageal atresia (EA) and tracheoesophageal fistula (TEF) has improved markedly over the years. But postoperative complications, however, have remained. This study evaluates recovery, preoperative, and postoperative status of patients with EA/TEF.

Methods: A retrospective study review was undertaken in 24 patients with EA/TEF after primary anastomosis (January 1975 through September 2003).

Results: There were no patients who had major cardiac anomalies or trisomy 18. In total, 17 of 24 (70.8%, group A) patients have survived and seven (29.2%, group B) have died. Birthweight and Apgar Scores in group A were significantly higher than in group B. The ratio of GAP (the distance of the location of the blind pouch from the ends of the upper and lower esophagus) to body length in group B was significantly higher than in group A. The birthweight and Apgar Scores in group A were significantly higher than in group B. When the authors compared their sample of cases by means of the Waterston classification, the Montreal classification and the Spitz classification, there were statistically significant differences between the results using the Waterston classification and the results using to the Spitz classification.

Conclusion: For the cases of EA surgery that were examined, the authors concluded that bodyweight at birth and the existence of pre‐surgery respiratory system complications have a significant effect on post‐surgery recovery, and that results appear to indicate the importance of classification using the Waterston classification and Spitz classification as a means of assessing the degree of risk. Results also appeared to indicate that the control of Respiratory Distress Syndrome throughout both the pre‐surgery and post‐surgery periods is critical.
The Political Color Line in America: Many “Peoples of Color” or Black Exceptionalism?
Authors: Sears David O. , Savalei Victoria
Published: November 2006

Despite the successes of the civil rights movement, a largely impermeable color line continues to restrict African Americans from assimilation into the broader American society. In the meantime high rates of immigration have produced an increasingly culturally diverse population. A “people of color” hypothesis suggests that the color line the new immigrants face resembles that imposed on African Americans. A “black exceptionalism” hypothesis suggests instead that the color line will be more porous for them, allowing for greater assimilation over successive generations, including a gradual weakening of politicized racial and ethnic group consciousness. Using data from Los Angeles County Social Surveys, we find that the largest new immigrant group, Latinos, like blacks, show strongly group‐interested policy preferences and strong group consciousness. However, both effects are stronger for recent Latino immigrants than for the U.S.‐born. We conclude that the new immigrant groups are increasingly likely to assimilate politically into the broader society in future generations, whereas a rather strict color line will continue to restrict blacks and maintain their distinctiveness.
Religious Attendance, Health Maintenance Beliefs, and Mammography Utilization: Findings from a Nationwide Survey of Presbyterian Women
Authors: BENJAMINS MAUREEN R. , TRINITAPOLI JENNY , ELLISON CHRISTOPHER G.
Published: November 2006

Preventive health services, such as mammography, play an increasingly important role in maintaining women's health. Social factors, such as religion, may influence utilization rates by expanding access, offering information, and increasing motivation. The current study examines the relationship between religious involvement, religious beliefs, and mammography usage in a nationally representative sample of Presbyterian women (N= 1,070). We use multivariate logistic regression models to estimate the influence of religious service attendance and two health‐related religious beliefs on self‐reported mammography use. The findings show that religious attendance is significantly associated with mammogram use. Women who attend services nearly every week are almost twice as likely to use mammograms compared to women who attend services less frequently or never. Furthermore, the belief that spiritual health is related to physical health is also associated with the use of mammograms.
Supply response in Ethiopia: accounting for technical inefficiency
Authors: Abrar Suleiman , Morrissey Oliver
Published: November 2006

Few empirical studies of supply response using the profit function have accounted for technical inefficiency. Using farm‐level panel data from Ethiopia, this study examines the effect of incorporating technical inefficiency in estimating the supply response of peasant farmers. Two systems of output supply and input demand equations are estimated and compared: the conventional model in which technical efficiency is assumed and another in which technical inefficiency is explicitly incorporated. The model with technical inefficiency is preferred on grounds of theoretical consistency and improved estimates, although model comparison tests are not conclusive. Incorporation of inefficiency generally increases the magnitudes and the statistical significance of own price elasticities, substantially so in the case of fertilizer and fertilizer‐intensive crops, and alters the priority attached to nonprice factors. An important result is that only the specification with inefficiency reveals a significant effect of access to extension services on output. Only this specification finds that output increases with household size, which one expects as the farms in the sample are largely subsistence and producing for own consumption. Furthermore, the results demonstrate that farmers' response to incentives is considerably restricted by inefficiency, suggesting that the traditional model would overstate response by excluding the efficiency variable.
Intellectual property piracy in a North–South context: empirical evidence
Authors: Goldsmith Peter , Ramos Gabriel , Steiger Carlos
Published: November 2006

The protection of intellectual property rights (IPR) has been a contentious issue for more than 20 years. Industrialized nations have moved to knowledge‐based economies, and simultaneously, trade barriers have fallen, making intellectual property (IP) vulnerable. Adding to this vulnerability are conflicting international institutional environments, belief systems, and economic realities. The debate over IPR protection has become a significant global trade issue pitting the net‐technology producing “North” against the net‐technology consuming “South.” With this in mind, there has been much debate about the impact of alternative IPR regimes (tight or loose) on the welfare of Southern economies. Policy makers, in both the South and the North, search for arguments to convince recalcitrant Southern countries to follow the Northern model of strict IPR regimes. The South, faced with a dilemma, searches for arguments to justify looser regimes or convince its populace that tighter regimes are in the best interest of the nation. The objective of this research is to add empirical clarity about the welfare impacts of weak IPR on the firm and host country. To this end, we employ a novel methodological design and unique context. The research design is deductive, in that we use the empirical setting of Pioneer‐Argentina, S.A., a seller of bioengineered agricultural seeds, to test the existing theory of weak IPR impacts in a North–South context.
A New Volume Warping Method for Surface Reconstruction
Authors: Azernikov Sergei , Fischer Anath
Published: November 2006

Volumetric models of 3D objects have recently been introduced into the reverse engineering (RE) process. Grid-based methods are considered as the major technique for reconstructing surfaces from these volumetric models. This is mainly due to the efficiency and simplicity of these methods. However, these grid-based methods suffer from a number of inherent drawbacks, resulting from the fact that the imposed Cartesian grid in general is not well adapted to the surface, neither in size nor in orientation. In order to overcome the above obstacles a new iso-surface extraction method is proposed for volumetric models. The main idea is first to construct a geometrical field that is induced by the object’s shape. This geometrical field represents the natural directions and a grid cell size for each point in the domain. Then, the imposed volumetric grid is deformed by the produced geometrical field toward the object’s shape. The iso-surface meshes can be extracted from the resulting adaptive grid by any conventional grid-based contouring technique. The proposed method provides better approximation of the unknown surface and exhibits anisotropy, which is present inherently in the surface. Moreover, since the produced meshes are quad-dominant, Catmull-Clark subdivision surfaces are directly constructed from these meshes.
Robotics projects as an integration exercise in a sophomore-junior level analog electronics course
Authors: Stevens Richard E. , Larkin John M.
Published: November 2006

A robotics project involving the custom design and implementation of analog transducers into LEGO robots has been added to our sophomore-junior level analog electronics course. This project allows the integration of circuit components whose properties and applications are learned throughout the course into a final unified project, motivates students to exercise initiative and creativity, and demonstrates a current application of analog electronics. Feedback both from students and the campus community has been very positive.