bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman shifted second harmonic backscattering of lasers in a magnetized plasma
Authors: Pathak Vishwa Bandhu , Tripathi V. K.
Published: September 2008

Raman shifted backward second harmonic generation, shifted by upper hybrid frequency, is seen as a strong signature of the existence of a transverse static magnetic field in the laser produced plasmas. An o-mode laser exerts a second harmonic longitudinal ponderomotive force on electrons, imparting them an oscillating velocity that acts as a driver to excite a space charge upper hybrid mode and a Raman shifted second harmonic backward electromagnetic wave.
Extreme “water repellency” on strong water-spreading surface without tilted degree actuation
Authors: Zheng Yongmei , Jiang Lei , Wang Jingxia , Han Dong
Published: September 2008

We report the self-running off phenomenon of microdroplet on strong water-spreading surface without any tilted degree actuation. It is found that when water droplet is deposited continuously gently on the porous superhydrophilic surface, the first droplet can spread strongly out in not more than 350 ms, while the subsequent droplet will run rapidly off the surface in 60–120 ms, in the absence of any tilted degree. It displays the more extreme “water repellency” than that of lotus leave or artificial superhydrophobic surfaces. This finding exhibits a unique way to design the antiadhesive surface using hydrophilic material.
Optical absorption spectra and monomer interaction in polymers: Investigation of exciton coupling in DNA hairpins
Authors: Burin A. L. , Dickman J. A. , Uskov D. B. , Hebbard C. F. F. , Schatz G. C.
Published: September 2008

We investigate the effect of exciton coupling on the optical absorption spectra of polymer molecules under conditions of strong inhomogeneous broadening. It is shown that the dependence of the maximum in the rescaled absorption spectrum on the number of monomers is determined by their resonant exciton coupling and is insensitive to inhomogeneous broadening. Thus the absorption spectrum can be used to determine optical interactions between monomers. Using our theory and semiempirical calculations we determine exciton coupling between adjacent AT pairs in DNA to be 0.04 eV and discuss exciton localization in DNA hairpins composed of AT pairs.
Honeycomb pattern array of vertically standing core-shell nanorods: Its application to Li energy electrodes
Authors: Kim Youn-Su , Ahn Hyo-Jin , Nam Sang Hoon , Lee Sang Ho , Shim Hee-Sang , Kim Won Bae
Published: September 2008

An energy storage electrode system is fabricated via a template method with one-dimensional nanostructures that are hexagonally patterned in a honeycomblike fashion and vertically standing nanorods made of a gold-coated carbon nanotube core and a V2O5 shell layer. The performance of this system for Li insertion and extraction shows an increased capacity along with an enhanced rate performance, which could be attributed to the aligned nanostructures having increased reaction sites, facilitated charge transport, and improved stability in the face of mechanical stress.
Quantitative differential interference contrast microscopy based on structured-aperture interference
Authors: Cui Xiquan , Lew Matthew , Yang Changhuei
Published: September 2008

We report a quantitative differential interference contrast (DIC) microscope based on a structured-aperture (SA) wavefront sensor. Unlike a conventional DIC microscope, the SA-DIC microscope can separate the amplitude and the phase gradient information of the image wavefront, and form quantitative intensity and DIC images of the sample with good resolution; our prototype achieved resolution ∼2 μm. Furthermore, due to the nonpolarization nature of the microscope, we were able to image birefringent samples without artifacts.
Influence of ferroelectricity on the photoelectric effect of LiNbO3
Authors: Dunn S. , Tiwari D.
Published: September 2008

A comparison between domain dependent photochemical and photoelectric cation reduction in LiNbO3 is presented. The reduction in photoelectric threshold for LiNbO3 due to the depolarization field allows UV irradiation to produce free electrons that can participate in photochemical reduction in silver nitrate. This is in addition to domain directed photophysics, where influences on the space charge layer due to the internal dipole of a ferroelectric determine the carrier at the surface. We show that the interaction of photoelectric and domain dependent influences is observed in LiNbO3 due to the low electron affinity (∼1–1.5 eV) and band bending (0.3–0.8 eV).
X-ray photoelectron spectroscopy energy band alignment of spin-on CoTiO3 high-k dielectric prepared by sol-gel spin coating method
Authors: Kao Kuo-Hsing , Chuang Shiow-Huey , Wu Woei-Cherng , Chao Tien-Sheng , Chen Jian-Hao , Ma Ming-Wen , Gao Reui-Hong , Chiang Michael Y.
Published: September 2008

The characteristics of CoTiO3 high-k dielectric prepared by sol-gel spin coating method had been demonstrated. High electrical permittivity (k∼40.2) of CoTiO3 dielectric was extracted via the transmission electron microscopy image and capacitance-voltage curves. In addition, the valence band offset between thermal SiO2 and spin-on CoTiO3 was about 4.0 eV, which was detected by x-ray photoelectron spectroscopy. The band gaps of thermal SiO2 and spin-on CoTiO3 were 9.0 and 2.2 eV, respectively. Energy band alignment of spin-on CoTiO3 directly with SiO2 and indirectly with Si was determined in this work.
Strain dependence of indirect band gap for strained silicon on insulator wafers
Authors: Munguía J. , Bremond G. , Bluet J. M. , Hartmann J. M. , Mermoux M.
Published: September 2008

We have used low temperature photoluminescence measurements in order to quantify the impact of strain effect on the Si indirect band gap in 9 nm thick tensely strained silicon on insulator layers. A redshift of the transverse optical phonon excitonic recombination in the strained silicon layer was evidenced as the strain in the layer is increased. Band gap shrinkages in the Δ direction equal to 130±3 meV, 184±3 meV, and 239±3 meV were obtained for 0.87±0.03%, 1.22±0.05%, and 1.54±0.06% strain values. These measured indirect transitions are in good agreement with the calculated strained silicon indirect band gap values.
Anisotropic optical gain in m-plane InxGa1−xN/GaN multiple quantum well laser diode wafers fabricated on the low defect density freestanding GaN substrates
Authors: Onuma T. , Okamoto K. , Ohta H. , Chichibu S. F.
Published: September 2008

The threshold power density for the stimulated emission (SE) at 400 nm of m-plane In0.05Ga0.95N/GaN multiple quantum well (QW) laser diode (LD) wafer excited with a stripe along the c-axis was found to be lower than along the a-axis, although the SEs exhibited transverse electric field mode for both configurations. The result was explained according to the polarization selection rules for the lowest and the second lowest energy interband transitions in anisotropically strained m-plane InGaN QWs. In case of the LD wafer lased at 426 nm, SE was observed only along the c-axis, where pronounced broadening of the gain spectrum was found. Because the equivalent internal quantum efficiency was only 44%, further reductions in nonradiative defect density and the width of gain spectrum are essential to realize longer wavelength LDs.
Asymmetric transport in asymmetric T-shaped graphene nanoribbons
Authors: Chen Yuan Ping , Xie Yue E. , Sun L. Z. , Zhong Jianxin
Published: September 2008

We propose an asymmetric T-shaped graphene nanoribbon (TGNR) that shows peculiar transport properties. In the vicinity of the Fermi level, the electron transmissions from the vertical graphene nanoribbon (GNR) to the two ends of the horizontal GNR are highly asymmetric. The electrons mostly transmit to one horizontal arm while are blocked by the other one. It is originated from the local asymmetric couplings between the intersection of the junction and the two horizontal arms. The asymmetric transport is very robust, even the T-shaped junction has a large size. Thus the asymmetric TGNR can be served as important components of nanocircuits.
Charge injection at carbon nanotube-SiO2 interface
Authors: Ong Hock Guan , Cheah Jun Wei , Chen Lang , TangTang Hosea , Xu Yanping , Li Bing , Zhang Hua , Li Lain-Jong , Wang Junling
Published: September 2008

Most single-wall carbon nanotube field-effect transistors show significant hysteresis in their transfer characteristics between forward and reverse gate bias sweeps. It was proposed that the hysteresis is due to a dynamic charging process at the carbon nanotube-dielectric interface. We have studied the charge injection and subsequent discharging processes at the carbon nanotube-SiO2 interface using electrostatic force microscopy. It was observed that the water layer assists charge diffusion on the dielectric surface.
A study of multirow-per-track bit patterned media by spinstand testing and magnetic force microscopy
Authors: Chen Y. J. , Huang T. L. , Leong S. H. , Hu S. B. , Ng K. W. , Yuan Z. M. , Zong B. Y. , Liu B. , Ng V.
Published: September 2008

We propose and demonstrate a concept of multirow-per-track bit patterned media (BPM) recording to overcome the problems encountered with the conventional one-row-per-track design. Focused ion beam was used on continuous granular perpendicular magnetic media to fabricate the prototype structures consisting of birow tracks with sub-100-nm single domain magnetic islands with the two rows of islands to be interleaved along the track direction, as well as an additional nonmagnetic spacer band between adjacent birow tracks for further bit aspect ratio (BAR)≥2 adjustment. Readback from such birow tracks with a two-row-wide read head was performed by dynamic spinstand testing. The proposed concept BPM provides many advantages including higher linear recording density (under the same lithographic limit), therefore enabling a higher data rate and a greater BAR≥2 for better integration with head design and servocontrol, as well as allowing the use of wider thus larger recording heads to improve writing efficiency for high density recording.
Current efficiency in organic light-emitting diodes with a hole-injection layer
Authors: Wang Hui , Klubek Kevin P. , Tang C. W.
Published: September 2008

We have systematically investigated the effect of layer structures on the current efficiency of prototypical hole-injection layer (HIL)/hole-transport layer (HTL)/electron-transport layer (ETL) organic light-emitting diodes based on 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA) as the HIL, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB) as the HTL, and tris(8-quinolinolato)aluminum (Alq) as the ETL. With bilayer devices, the current efficiency is limited by exciplex emissions in the case of MTDATA/Alq and quenching of Alq emissions by NPB+ radical cations in NPB/Alq. The improved current efficiency in trilayer MTDATA/NPB/Alq devices can be attributed to a reduction in NPB+ radical cations at the NPB/Alq interface and a strong electric field in the NPB layer.
Converse magnetoelectric effects on heterotype electrostrain-piezopermeability composites
Authors: Fang X. , Zhang N. , Wang Z. L.
Published: September 2008

By using the product effect of electrostrain and piezopermeability, a heterotype composite consisting of a bar of Pb(Zr,Ti)O3 and a ring of MnZn ferrite with higher permeability has been developed, and its converse magnetoelectric effect has been investigated. Under a constant electric field of 5 kV/cm, about 20% electric-field-induced changes in permeability and impedance have been observed with the composite device over a wide frequency band. The electric-field dependence of the permeability and impedance shows a ferroelectric relaxation behavior. This composite is a candidate material for electrically controlled magnetic devices.
Ti-based nonalloyed Ohmic contacts for Al0.15Ga0.85N∕GaN high electron mobility transistors using regrown n+-GaN by plasma assisted molecular beam epitaxy
Authors: Seo Hui-Chan , Chapman Patrick , Cho Hyun-Ick , Lee Jung-Hee , Kim Kyekyoon (Kevin)
Published: September 2008

A technique for regrowing n+-GaN layers has been developed to realize nonalloyed Ohmic contacts using plasma assisted molecular beam epitaxy. The contact resistance and device performance were measured of a recessed-gate with the regrowth and of recessed-source/drain AlGaN∕GaN high electron mobility transistors (HEMTs). With the regrown n+-GaN layers and recessed drain/source, a low contact resistance of 0.6Ωmm was obtained for Ti∕Au contacts to AlGaN. The peak drain current (IDS,max) and maximum transconductance (gm,max) of the AlGaN∕GaN HEMTs with nonalloyed Ohmic contacts were 573mA∕mm and 60mS∕mm, respectively. These results demonstrate that the regrowth of highly doped GaN layers is crucial in achieving low-resistance nonalloyed Ohmic contacts for the HEMT structures.
Modal analysis of a multimode polarization-maintaining plastic optical fiber fabricated using poly(methyl methacrylate/benzyl methacrylate) copolymer
Authors: Furukawa Rei A. , Tagaya Akihiro , Koike Yasuhiro
Published: September 2008

We report an experimental demonstration of a multimode polarization-maintaining fiber that has extinction ratio (ER) of 14.0dB at 1m propagation, and this value was compared to those measured from different kinds of commercially available multimode fibers. The sample fiber was fabricated using poly(methyl methacrylate/benzyl methacrylate), which we named as polarization-maintaining graded-index plastic optical fiber. A measurement setup was developed in order to measure the ER in the cases when different points of the fiber core was launched. Birefringence and the output near field pattern for each launching points have exhibited a clear correlation to the measured ER.l
Electron injection of SrTiO3∕Si interfacial layer
Authors: Ma J. H. , Sun J. L. , Qin J. H. , Gao Y. H. , Lin T. , Shen H. , Shi F. W. , Meng X. J. , Chu J. H. , Liu S. J. , Li J.
Published: September 2008

The electrical properties of the SrTiO3(STO)∕Si interfacial layer were studied by measuring STO metal-insulator-semiconductor (MIS) structure. The C-V measurements showed that there existed electron injection at the STO/Si interface under the higher sweep voltages. The electron injection behavior was analyzed and discussed in detail. By analyzing the voltage distribution of the semiconductor Si, the insulator STO, and the STO/Si interfacial layer in MIS structure, the electron injection electric field of interfacial layer was estimated to be about 5.5MV∕cm.
Enhancement of electron injection into a light-emitting polymer from an aluminum oxide cathode modified by a self-assembled monolayer
Authors: Vaynzof Yana , Dennes T. Joseph , Schwartz Jeffrey , Kahn Antoine
Published: September 2008

A self-assembled monolayer (SAM) of octylphosphonate was deposited on an AlOx electrode using the tethering by aggregation and growth (T-BAG) procedure. Ultraviolet photoemission spectroscopy (UPS) measurements showed a decrease in the substrate work function from 3.8to3.3eV. Poly[9,9′-dioctylfluorene-co-bis-N,N′-(4-butylphenyl)-diphenylamine] (TFB) films spin coated on the bare and the SAM-modified oxide surfaces were investigated by UPS. A shift in molecular levels, corresponding to a reduction in the electron injection barrier, was observed for the SAM-modified electrode. This barrier lowering was confirmed by current-voltage measurements showing a corresponding increase in electron current through the TFB/SAM/AlOx device.
Identification of a gain-of-function mutation of the prolactin receptor in women with benign breast tumors
Authors: Bogorad Roman L. , Courtillot Carine , Mestayer Chidi , Bernichtein Sophie , Harutyunyan Lilya , Jomain Jean-Baptiste , Bachelot Anne , Kuttenn Frédérique , Kelly Paul A. , Goffin Vincent , Touraine Philippe ,   the Benign Breast Diseases Study Group
Published: September 2008

There is currently no known genetic disease linked to prolactin (Prl) or its receptor (PrlR) in humans. Given the essential role of this hormonal system in breast physiology, we reasoned that genetic anomalies of Prl/PrlR genes may be related to the occurrence of breast diseases with high proliferative potential. Multiple fibroadenomas (MFA) are benign breast tumors which appear most frequently in young women, including at puberty, when Prl has well-recognized proliferative actions on the breast. In a prospective study involving 74 MFA patients and 170 control subjects, we identified four patients harboring a heterozygous single nucleotide polymorphism in exon 6 of the PrlR gene, encoding Ile
146
→Leu substitution in its extracellular domain. This sole substitution was sufficient to confer constitutive activity to the receptor variant (PrlR
I146L
), as assessed in three reconstituted cell models (Ba/F3, HEK293 and MCF-7 cells) by Prl-independent (
i
) PrlR tyrosine phosphorylation, (
ii
) activation of signal transducer and activator of transcription 5 (STAT5) signaling, (
iii
) transcriptional activity toward a Prl-responsive reporter gene, and (
iv
) cell proliferation and protection from cell death. Constitutive activity of PrlR
I146L
in the breast sample from a patient was supported by increased STAT5 signaling. This is a unique description of a functional mutation of the PrlR associated with a human disease. Hallmarks of constitutive activity were all reversed by a specific PrlR antagonist, which opens potential therapeutic approaches for MFA, or any other disease that could be associated with this mutation in future.
Regulation of the endocycle/gene amplification switch by Notch and ecdysone signaling
Authors: Sun Jianjun , Smith Laila , Armento Alexander , Deng Wu-Min
Published: September 2008

The developmental signals that regulate the switch from genome-wide DNA replication to site-specific amplification remain largely unknown. Drosophila melanogaster epithelial follicle cells, which begin synchronized chorion gene amplification after three rounds of endocycle, provide an excellent model for study of the endocycle/gene amplification (E/A) switch. Here, we report that down-regulation of Notch signaling and activation of ecdysone receptor (EcR) are required for the E/A switch in these cells. Extended Notch activity suppresses EcR activation and prevents exit from the endocycle. Tramtrack (Ttk), a zinc-finger protein essential for the switch, is regulated negatively by Notch and positively by EcR. Ttk overexpression stops endoreplication prematurely and alleviates the endocycle exit defect caused by extended Notch activity or removal of EcR function. Our results reveal a developmental pathway that includes down-regulation of Notch, activation of the EcR, up-regulation of Ttk to execute the E/A switch, and, for the first time, the genetic interaction between Notch and ecdysone signaling in regulation of cell cycle programs and differentiation.
Rab13 regulates membrane trafficking between TGN and recycling endosomes in polarized epithelial cells
Authors: Nokes Rita L. , Fields Ian C. , Collins Ruth N. , Fölsch Heike
Published: September 2008

To maintain polarity, epithelial cells continuously sort transmembrane proteins to the apical or basolateral membrane domains during biosynthetic delivery or after internalization. During biosynthetic delivery, some cargo proteins move from the trans-Golgi network (TGN) into recycling endosomes (RE) before being delivered to the plasma membrane. However, proteins that regulate this transport step remained elusive. In this study, we show that Rab13 partially colocalizes with TGN38 at the TGN and transferrin receptors in RE. Knockdown of Rab13 with short hairpin RNA in human bronchial epithelial cells or overexpression of dominant-active or dominant-negative alleles of Rab13 in Madin-Darby canine kidney cells disrupts TGN38/46 localization at the TGN. Moreover, overexpression of Rab13 mutant alleles inhibits surface arrival of proteins that move through RE during biosynthetic delivery (vesicular stomatitis virus glycoprotein [VSVG], A-VSVG, and LDLR-CT27). Importantly, proteins using a direct route from the TGN to the plasma membrane are not affected. Thus, Rab13 appears to regulate membrane trafficking between TGN and RE.
Reshaping of the endoplasmic reticulum limits the rate for nuclear envelope formation
Authors: Anderson Daniel J. , Hetzer Martin W.
Published: September 2008

During mitosis in metazoans, segregated chromosomes become enclosed by the nuclear envelope (NE), a double membrane that is continuous with the endoplasmic reticulum (ER). Recent in vitro data suggest that NE formation occurs by chromatin-mediated reorganization of the tubular ER; however, the basic principles of such a membrane-reshaping process remain uncharacterized. Here, we present a quantitative analysis of nuclear membrane assembly in mammalian cells using time-lapse microscopy. From the initial recruitment of ER tubules to chromatin, the formation of a membrane-enclosed, transport-competent nucleus occurs within ∼12 min. Overexpression of the ER tubule-forming proteins reticulon 3, reticulon 4, and DP1 inhibits NE formation and nuclear expansion, whereas their knockdown accelerates nuclear assembly. This suggests that the transition from membrane tubules to sheets is rate-limiting for nuclear assembly. Our results provide evidence that ER-shaping proteins are directly involved in the reconstruction of the nuclear compartment and that morphological restructuring of the ER is the principal mechanism of NE formation in vivo.
The mouth of a dense-core vesicle opens and closes in a concerted action regulated by calcium and amphiphysin
Authors: Llobet Artur , Wu Minnie , Lagnado Leon
Published: September 2008

Secretion of hormones and peptides by neuroendocrine cells occurs through fast and slow modes of vesicle fusion but the mechanics of these processes are not understood. We used interference reflection microscopy to monitor deformations of the membrane surface and found that both modes of fusion involve the tightly coupled dilation and constriction of the vesicle. The rate of opening is calcium dependent and occurs rapidly at concentrations <5 μM. The fast mode of fusion is blocked selectively by a truncation mutant of amphiphysin. Vesicles do not collapse when fusion is triggered by strontium, rather they remain locked open and membrane scission is blocked. In contrast, constriction of the vesicle opening continues when endocytosis is blocked by inhibiting the function of dynamin. Thus, fast and slow modes of fusion involve similar membrane deformations and vesicle closure can be uncoupled from membrane scission. Regulation of these processes by calcium and amphiphysin may provide a mechanism for controlling the release of vesicle contents.
Quantification of Wheat TAXI and XIP Type Xylanase Inhibitors: A Comparison of Analytical Techniques
Authors: Gebruers Kurt , Beaugrand Johnny , Croes Evi , Dornez Emmie , Courtin Christophe M. , Delcour Jan A.
Published: September 2008

To date, three different techniques are available for the quantification of TAXI and XIP type proteinaceous xylanase inhibitors in cereals. A first approach is based on the determination of the residual activities of xylanases (also referred to as endo‐1,4‐β‐d‐xylanases, EC 3.2.1.8), which are specifically inhibited by these inhibitors, after incubation with sample containing the inhibitors. The other two techniques are immunoblotting and ELISA which are based on recognition of TAXI and XIP proteins by specific antibodies. TAXI, as well as XIP, are easily extracted by aqueous buffers. Hence, the large difference in their concentrations (2–10 fold higher for XIP than for TAXI in whole meal) is not caused by differences in extractability. The repeatabilities of the three techniques are comparable. The intra‐assay and inter‐assay coefficients of variation were 6–7 and 10–14%, respectively, which is in the range of values described for methods to quantify other compounds in plant and animal tissues. The three methods give comparable results, suggesting they have similar accuracies. The choice of the technique to be used will depend not only on the sensitivity and dynamic range needed, but also on its technical simplicity and the need for high‐throughput analysis.
Site of Origin of Volatile Compounds in Cooked Rice
Authors: Yang Dong Sik , Lee Kyu‐Seong , Kim Kee‐Jong , Kays Stanley J.
Published: September 2008

Volatile compounds emanating from three cultivars of cooked rice milled to different degrees (0, 8, and 30% by weight) were compared to ascertain their site of origin and the effect of pigmentation on synthesis. The cultivars tested were Ilpumbyeo (traditional white rice), Heugjinjubyeo (black pigmented), and Jeogjinjubyeo (red pigmented). In total, 29, 38, and 27 volatile compounds were identified in dehulled, unmilled Ilpumbyeo, Heugjinjubyeo, and Jeogjinjubyeo, respectively. Significant quantitative and qualitative differences were found among the cultivars in their volatile profiles. 2‐Acetyl‐1‐pyrroline, guaiacol, 1‐nonanol, 3‐octen‐2‐one, 1,2‐dimethoxybenzene, pyridine, and pyrrole were found only in Heugjinjubyeo and phenylacetaldehyde only in Jeogjinjubyeo. Removal of the bran, partial endosperm, and pigment qualitatively and quantitatively affected the volatile compounds formed, with certain volatiles higher in unmilled rice (0% milling), indicating the pericarp and aleurone layer (bran) as their primary site of origin. Volatiles emanating from the 8 and 30% milled samples indicated the outer and middle endosperm (8%) and core endosperm (30%) as the primary sites of origin. Therefore, differences in chemical composition with location within the grain appear to account for the quantitative and qualitative variation in volatile synthesis.
Dietary Inclusion of Wheat Bran Arabinoxylooligosaccharides Induces Beneficial Nutritional Effects in Chickens
Authors: Courtin Christophe M. , Broekaert Willem F. , Swennen Katrien , Lescroart Olivier , Onagbesan Okanlawon , Buyse Johan , Decuypere Eddy , Van de Wiele Tom , Marzorati Massimo , Verstraete Willy , Huyghebaert Gerard , Delcour Jan A.
Published: September 2008

In vivo experiments were conducted to verify whether arabinoxylooligosaccharides (AXOS) obtained as low molecular mass compounds by enzymic hydrolysis from wheat bran arabinoxylan (AX) can exert nutritional effects. Two feeding trials were performed on chickens fed diets with either wheat or maize as the main component. Supplementation of bran AXOS at either 0.5% (w/w) to the wheat‐based diet or at 0.25% (w/w) to the maize‐based diet diets significantly (P < 0.05) improved the feed conversion rate without increasing the body weight of the animals, thus pointing to improved nutrient utilization efficiency. The positive effect of bran AXOS supplementation on feed utilization efficiency was similar to that obtained by adding an AX‐degrading xylanase directly to the wheat‐based diet. No significant effect on feed utilization efficiency was obtained with another type of nondigestible oligosaccharide such as fructooligosaccharides (FOS) derived from chicory roots. Bran AXOS significantly increased the level of bifidobacteria but not total bacteria in the caeca of the chickens, an effect not observed with either xylanase or FOS addition. These data suggest that bran AXOS have beneficial nutritional effects and may act as prebiotics.
Bread Quality of Spelt Wheat and Its Starch
Authors: Wilson J. D. , Bechtel D. B. , Wilson G. W. T. , Seib P. A.
Published: September 2008

Flours from five spelt cultivars grown over three years were evaluated as to their breadbaking quality and isolated starch properties. The starch properties included amylose contents, gelatinization temperatures (differential scanning calorimetry), granule size distributions, and pasting properties. Milled flour showed highly variable protein content and was higher than hard winter wheat, with short dough‐mix times indicating weak gluten. High protein cultivars gave good crumb scores, some of which surpassed the HRW baking control. Loaf volume was correlated to protein and all spelt cultivars were at least 9–51% lower than the HRW control. Isolated starch properties revealed an increase in amylose in the spelt starches of 2–21% over the hard red winter wheat (HRW) control. Negative correlations were observed for the large A‐type granules to bread crumb score, amylose level, and final pasting viscosity for cultivars grown in year 1999 and to pasting temperature in 1998 samples. Positive correlations were found for the small B‐ and C‐type granules relative to crumb score, loaf volume, amylose, and RVA final pasting viscosity for cultivars grown in 1999, and to RVA pasting temperature for samples grown in 1998. The environmental impact on spelt properties seemed to have a greater effect than genetic control.
Association of Avenanthramide Concentration in Oat (Avena sativa L.) Grain with Crown Rust Incidence and Genetic Resistance
Authors: Wise Mitchell L. , Doehlert Douglas C. , McMullen Michael S.
Published: September 2008

Avenanthramides (avn) are antioxidant compounds found in oat tissues, including the grain, that are of interest from a nutritional standpoint. In this study, we have measured avenanthramide concentration in the grain of 18 oat genotypes grown in six environments. These genotypes varied widely in crown rust (Puccinia coronata) resistance. Crown rust infected two of the six environments studied. The grain avenanthramide concentrations in the crown rust environments were significantly higher than those in the uninfected environments. Avenanthramide concentrations in the crown rust infected environments was also significantly correlated with their genetic crown rust resistance, as evaluated in the field. These results suggest that avenanthramide accumulation in the grain is associated with crown rust infection and that, in most of the cultivars evaluated, the extent of their accumulation also correlated with their genetic disease resistance; avenanthramide accumulation in the grain was, with noted exceptions, highest in those cultivars showing the greatest genetic resistant to crown rust.
Physical and Milling Characteristics of Wheat Kernels After Enzyme and Acid Treatments
Authors: Lamsal B. P. , Yoo J. H. , Haque E. , Faubion J. M.
Published: September 2008

The current wheat milling process separates bran from endosperm by passing tempered wheat kernels through successive break rolls and sifters. Using hydrolytic enzymes during tempering degrades bran and aleurone layers and can improve milling efficiency and yield. This study was conducted to evaluate the effects of chemical and enzymatic treatments of wheat kernels before milling on physical and milling characteristics of the resulting wheat and flour quality. Hard wheat kernels were soaked in dilute acid or water and dried back to original moisture before being tempered with enzymes in water. Kernel physical and milling characteristics (600 g) were evaluated. Dilute acid soaking did not affect the 1,000‐kernel weight and diameter but softened treated kernels. When treated kernels were pearled, bran removal was mostly from ends; and the reducing sugar content in enzyme‐treated bran was significantly higher than the control. Compared with the control, acid‐soaked enzyme‐tempered kernels showed small but significant improvement in straight flour yield, with virtually no difference in protein content, and flour color. Chemical and enzyme treatment resulted in higher ash in flour. These differences were not seen in milling of larger batches (1,500 g) of kernels.
Modification of Standard Enzymatic Protocol to a Cost‐Efficient Format for Mixed‐Linkage (1→3,1→4)‐β‐d‐Glucan Measurement
Authors: Hu Gongshe , Burton Charlotte
Published: September 2008

The current enzymatic assay approach (AACC International Approved Method 32‐23) for the measurement of mixed‐linkage β‐glucan in small grains was modified to a cost‐efficient and high‐throughput format without compromising the accuracy of the results. Ten barley (Hordeum vulgare L.) genotypes used in the study represented a wide range of β‐glucan content levels. A reduced reaction volume is used in the new protocol to adapt to a 96‐well plate format. The volume of key components lichenase and β‐glucosidase were reduced to 25% of the volume required in the original protocol and the cost per sample was reduced to 22% of that in the original protocol. Labor cost was also decreased to 25% of the original protocol as a result of format changes. The accuracy of the measurement from the modified protocol was comparable to the current standard enzymatic procedure. β‐Glucan measurement accuracy of the modified and original protocols were also compared using 21 oat (Avena sativa L.) samples. The results indicated that the new protocol consistently produced accurate measurements in both barley and oat.
Oat Grain Density Measurement by Sand Displacement and Analysis of Physical Components of Test Weight
Authors: Doehlert Douglas C. , McMullen Michael S.
Published: September 2008

Test weight or bulk density of oats (Avena sativa L.) has a major influence on the monetary value of oat grain. We hypothesize that test weight can be attributed to grain density and packing efficiency. We have measured oat grain volume and density by a sand‐displacement method and derived the packing factor for six oat cultivars grown in three environments. Volumes of individual grains were 31–38 mm3 and were highly correlated with grain mass. Grain densities were 0.96–1.03 g/cm3. Packing efficiency, defined as the space proportion occupied by the grains, was 53–55%. Regression analysis suggested that 78% of the variation in test weight could be attributed to grain density. Size fractionation of grain by sieving and analysis by digital image analysis indicated that smaller grains within an oat sample packed more efficiently than larger grains and larger grains in a sample were less dense than the smaller grains. Analysis of oat grain components indicated groat densities were ≈1.29 g/cm3 and hull densities were ≈0.69 g/cm3. The difference in densities between groat and hull provide a physical basis for the recognized relationship between groat percentage and test weight.
Hydration Dynamics of Durum Wheat Endosperm as Studied by Magnetic Resonance Imaging and Soaking Experiments
Authors: Kratzer A. , Handschin S. , Lehmann V. , Gross D. , Escher F. , Conde‐Petit B.
Published: September 2008

The precise knowledge of the kinetics of water transport in durum wheat endosperm is a prerequisite for the optimization of wheat processing techniques like pasta dough mixing on a fundamental basis. Pieces of endosperm were cylindrically cut, prepared from durum wheat kernels, and used to study the water uptake by applying a gravimetric method and magnetic resonance imaging (MRI). The total water uptake of endosperm cylinders at different soaking times was determined by gravimetric soaking experiments and revealed a swelling limit of ≈40 g/100 g wb after 60 min. With these results it was possible to estimate an apparent diffusion coefficient of water in durum endosperm by using numerical simulation based on a diffusion model (D25°C ~ 0.76 × 10–10 m2/sec). MRI was used to quantify the water distribution in the endosperm cylinders over time at excess and limited water conditions. The calibration of MRI for the quantification of local and time‐dependent water contents was successful by correlating the spin‐spin relaxation time (T2) with the water content of calibration samples at intermediate moisture levels (19–45 g/100 g wb). Water content maps were generated and showed the kinetics of water distribution inside the endosperm cylinders up to equilibrium conditions. The water uptake of the endosperm cylinders over time, as measured by MRI, fitted well to the water uptake as determined gravimetrically in soaking tests, which validated the applied MRI calibration and measurement procedures. The results allow the quantitative prediction of water transport properties of durum wheat endosperm during moistening procedures.
Study of Viscoelastic Properties of Wheat Kernels Using Compression Load Method
Authors: Ponce‐García N. , Figueroa J. D. C. , López‐Huape G. A. , Martínez H. E. , Martínez‐Peniche R.
Published: September 2008

The method to measure hardness and other viscoelastic properties of intact wheat kernels is presented. Wheat with 9.3% moisture showed high elastic behavior compared with wheat tempered at 22.5% moisture that showed a plastic behavior. Load‐deformation curves showed that bread wheat behaves as a more plastic material than durum wheat, which is a more elastic material. Yield point of all the wheat samples was ≈18.5 N, independent of wheat type and moisture content. The height of the wheat kernel increased linearly, and the compression area increased exponentially, with increasing moisture content. The modulus of elasticity of wheat ranged from 99.2 MPa for 22.5% moisture content to 394.8 MPa for 9.3% moisture content. Young's modulus range for soft wheat such as Salamanca, Saturno, and Cortazar cultivars was 232.2–308.5 MPa, as compared with Rayón bread wheat at 321.5 MPa and the Altar, Sofía, and Rafi cultivars of durum wheat that had elastic moduli of 438.7–485.8 MPa. The compression force and final stress decreased from 69.9 N and 40.1 MPa in soft wheat to 90 N and 78.9 MPa in durum, respectively. Total work range was 14.7 MPa/sec in soft wheat to 19.7 MPa/sec for durum wheat and, as expected, was higher in the durum and bread wheat than in soft wheat. The plastic part ranged from 2.4 MPa/sec in soft wheat to 0.6 MPa/sec in durum wheat.
Description of Chemical Changes Implied During Bread Dough Mixing by FT‐ATR Mid‐Infrared Spectroscopy
Authors: Kaddour A. Aït , Mondet M. , Cuq B.
Published: September 2008

The aim of the present study was to investigate the ability of mid‐infrared (MIR) spectroscopy to identify physicochemical changes in the French bread dough mixing process. An ATR FT‐MIR spectrometer at 4000–800 cm–1 was used. The MIR spectra collections recorded during mixing were analyzed after standard normal variate using principal component analysis (PCA) and after second‐derivative treatment. The results were interpreted in terms of chemical changes involved in dough development and more particularly in terms of secondary structural protein changes (amide III). The loading spectrum associated with principal component 1 (PC1) allows three MIR wave number regions of variations (3500–3000, 1700–1200, and 1200–800 cm–1) to be identified. The loading spectrum associated with PC1 describes an increase in the relative protein band intensities and a decrease in relative water and starch band intensities. The variation during bread dough mixing time of the different amide III bands identified after the second‐derivative show that α‐helical, β‐turn, and β‐sheet structures increase while random coil structure decreases, suggesting that the gluten structure is becoming a more ordered structure. The MIR mixing time identified as being the maximum scores value on the PC1 scores plots was associated with the time at which the dough apparent torque begin to collapse, suggesting that the MIR spectroscopy could monitor bread dough development.
Formation of Oligosaccharides and Polysaccharides by Lactobacillus reuteri LTH5448 and Weissella cibaria 10M in Sorghum Sourdoughs
Authors: Schwab Clarissa , Mastrangelo Mario , Corsetti Aldo , Gänzle Michael
Published: September 2008

Gluten‐free breads, which are composed of gluten‐free flours, starch, and hydrocolloids, differ from wheat and rye breads in relation to texture, volume, and crumb structure. Moreover, the dietary fiber content is lower compared with wheat or rye breads. Cereal isolates of lactic acid bacteria frequently produce oligo‐ and homopolysaccharides from sucrose, which can improve the nutritional and technological properties of gluten‐free breads as prebiotic carbohydrates and hydrocolloids, respectively. Sorghum sourdough was fermented with Lactobacillus reuteri LTH5448 or Weissella cibaria 10M, which synthesize fructooligosaccharides (FOS) and levan, and isomaltooligosaccharides and dextran, respectively. The gluten‐free bread was produced with 14% sourdough addition. L. reuteri LTH5448 formed FOS and 1.5 g of levan/kg DM in quinoa sourdoughs. FOS were digested by the baker's yeast during proofing, and the levan could be qualitatively detected in the bread. W. cibaria 10M produced >60 g of isomaltooligosaccharides/kg DM and 0.6 g of dextran/kg DM, which could still be detected in the bread. Breads prepared with W. cibaria 10M were less firm compared with breads prepared with L. reuteri LTH5448 or a FOS and levan‐negative mutant of L. reuteri LTH5448. The addition of sourdoughs fermented with oligo‐ and polysaccharide forming starter cultures can increase the content of prebiotic oligosaccharides in gluten‐free breads.
Enhancing Water Removal from Whole Stillage by Enzyme Addition During Fermentation
Authors: Henriques Ana Beatriz , Johnston David B. , Al‐Dahhan Muthanna
Published: September 2008

The removal of water from coproducts in the fuel ethanol process requires a significant energy input. In this study, the addition of commercially available cell‐wall‐degrading enzymes was investigated to determine whether or not the enzymes could reduce the amount of water bound within the wet grains. This would have the effect of allowing more water to be removed during centrifugation, reducing the time and energy needed during the drying process. The experiment screened 15 cell‐wall‐degrading enzyme preparations. A significant reduction in water‐binding capacity was found for a number of enzymes tested in the initial screening. The experiment was repeated and two enzymes were identified to have the highest whole stillage dewatering effect, 15 and 14% more water removed for enzyme preparations A and G, respectively. Adding different enzyme preparation amounts to the mash showed varying effects, with the potential to allow for an optimization of enzymes cost and energy savings. In some cases, an enzyme dosage of 0.5 mL worked as well, if not better, than a dosage of 1 mL. These results can translate into improvements in the overall energy efficiency of the process because the wet grains entering the drier would contain less moisture than in the conventional process thus requiring a shorter residence time in the drier.
Flavor Volatiles in Three Rice Cultivars with Low Levels of Digestible Protein During Cooking
Authors: Zeng Zhi , Zhang Han , Zhang Tao , Chen Jie Yu
Published: September 2008

A modified headspace solid‐phase microextraction (SPME) method in conjunction with gas chromatography‐mass spectrometry (GC‐MS) has been used for the analysis of the flavor volatiles in three rice cultivars with low levels of digestible protein during cooking. Altogether, 77 volatile compounds were identified, of which 13 components were not previously reported in rice. A total of 61, 71, and 74 peaks, respectively, were assigned to Shunyou, LGC‐katsu, and LGC‐soft. Compounds that have been highlighted previously as flavor molecular markers in rice, including indole, vanillin, (E,E)‐2,4‐decadienal, (E)‐2‐nonenal, 2‐pentylfuran, and 2‐methoxy‐4‐vinylphenol, etc., were on the list of those identified components. Furthermore, similarities and differences of the flavor volatiles among the three rice cultivars were observed. Shunyou was characterized by a relatively higher amount of indole and LGC‐katsu had a very high amount of 4‐vinylphenol while both rice cultivars displayed an absence of vanillin, pentyl hexanoate, and hexyl hexanoate. In contrast, LGC‐soft contained vanillin and had an abundance of fatty acid esters such as pentyl hexanoate and hexyl hexanoate, together with a higher amount of γ‐nonalactone.
Association Between % SDS‐Unextractable Polymeric Protein (%UPP) and End‐Use Quality in Chinese Bread Wheat Cultivars
Authors: Zhang Pingping , He Zhonghu , Zhang Yan , Xia Xianchun , Chen Dongshen , Zhang Yong
Published: September 2008

Trial I, with 33 spring cultivars, and trial II, with 21 winter cultivars, sown in four environments in the northwestern China spring wheat region and northern winter wheat region, respectively, were used to study the effect of genotype and environment on the size distribution of polymeric proteins. Association between quantity and size distribution of polymeric protein and dough properties (both trials) and northern‐style Chinese steamed‐bread (CSB) (trial I) and pan bread (trial II) qualities were also investigated. In trial I, all protein attributes, such as flour protein content, SDS‐extractable polymeric protein in the flour (EPP), SDS‐unextractable polymeric protein in the flour (UPP), and percent UPP in total polymeric protein (%UPP), were largely determined by environment, whereas variation in dough strength resulted from variation in UPP and %UPP across environments. In trial II, EPP was largely determined by environment, and UPP and %UPP were largely determined by genotype. These differences might result from different levels of protein content and dough strength in the two trials. The EPP was positively correlated with dough extensibility and was generally negatively correlated with dough stability and maximum resistance in both trials. However, %UPP was significantly positively correlated with dough stability and maximum resistance and end‐use quality in both trials. In trial I, correlation coefficients between %UPP and maximum resistance and CSB score were r = 0.90 and 0.71, respectively, whereas in trial II, the correlation coefficients between %UPP and maximum resistance and pan bread score were 0.96 and 0.87, respectively. Therefore, selection for high %UPP together with high‐quality glutenin subunits should lead to improved dough strength and end‐use quality in Chinese wheats.
Impact of Presoaking on Flavor of Cooked Rice
Authors: Champagne E. T. , Bett‐Garber K. L. , Thomson J. L. , Shih F. F. , Lea J. , Daigle K.
Published: September 2008

Soaking rice in water for 30 min or longer before cooking is traditionally practiced in Japan, Korea, and other Asian countries. When soaked, the rice grains hydrate, develop cracks, and water is absorbed. Soaking facilitates uniform cooking and shortens cooking time. The cooked kernel is usually less firm. The present study was undertaken to determine the effects of presoaking on the flavor of cooked rice and whether flavor differences are associated with textural changes that could influence retention of aroma compounds. Eleven samples of short, medium, and long grain milled rice representing scented and nonscented rice and a wide range of amylose contents were presented to a descriptive sensory panel. For the set of all rice samples, undesirable sewer/animal flavor significantly increased and sweet taste significantly decreased with presoaking for 30 min. For individual rice samples, significantly higher sewer/animal intensity was observed with presoaking for the 2 Basmati rice samples and one of the U.S. long grain rice samples. When presoaked, sweet taste was significantly lower in one of the Basmati and Jasmine rice samples, the U.S. medium grain rice, and one U.S. long grain rice. Water‐like metallic was also significantly higher in one presoaked Basmati sample. Presoaking also resulted in significant increases in summed negative flavor attributes and significant decreases in summed positive flavor attributes for the set of all rice samples. The effects of presoaking on texture, as measured by TPA hardness and chewiness, did not explain the observed increases in negative flavor attributes. An increase in free sulfur‐containing free amino acids with presoaking could have resulted in an increase of their breakdown products, thereby contributing to the increase in sewer/animal flavor. The decreases in sweet taste and summed positive flavor attributes were likely the result of masking caused by the increases in sewer/animal and summed negative flavor attributes.