bluuebunny/crossref_metadata_2025_split huggingface dataset:
Power‐based, phase‐informed selection of single nucleotide polymorphisms for disease association screens
Authors: Saccone Scott F. , Rice John P. , Saccone Nancy L. 
Published: May 2006

AbstractSingle nucleotide polymorphisms (SNPs) are becoming widely used as genotypic markers in genetic association studies of common, complex human diseases. For such association screens, a crucial part of study design is determining what SNPs to prioritize for genotyping. We present a novel power‐based algorithm to select a subset of tag SNPs for genotyping from a map of available SNPs. Blocks of markers in strong linkage disequilibrium (LD) are identified, and SNPs are selected to represent each block such that power to detect disease association with an underlying disease allele in LD with block members is preserved; all markers outside of blocks are also included in the tagging subset. A key, novel element of this method is that it incorporates information about the phase of LD observed among marker pairs to retain markers likely to be in coupling phase with an underlying disease locus, thus increasing power compared to a phase‐blind approach. Power calculations illustrate important issues regarding LD phase and make clear the advantages of our approach to SNP selection. We apply our algorithm to genotype data from the International HapMap Consortium and demonstrate that considerable reduction in SNP genotyping may be attained while retaining much of the available power for a disease association screen. We also demonstrate that these tag SNPs effectively represent underlying variants not included in the LD analysis and SNP selection, by using leave‐one‐out tests to show that most (approximately 90%) of the “untyped” variants lying in blocks are in coupling‐phase LD with a tag SNP. Additional performance tests using the HapMap ENCyclopedia of DNA Elements (ENCODE) regions show that the method compares well with the popular r2 bin tagging method. This work is a concrete example of how empirical LD phase may be used to benefit study design. Genet. Epidemiol. 2006. © 2006 Wiley‐Liss, Inc.
Rapid and cleaner synthesis of 1,4‐dihydropyridines in aqueous medium
Authors: Sivamurugan V. , Vinu A. , Palanichamy M. , Murugesan V. 
Published: May 2006

AbstractThe present investigation deals with a novel water soluble Lewis acid complex, Zn[(L)proline]2 catalyzed Hantzsch 1,4‐dihydropyridine derivatives syntheses in aqueous medium assisted by microwave irradiation. The microwave promoted syntheses in aqueous medium afforded moderate to excellent yield (up to 98%) within short reaction time and allowed the reaction to take place with low microwave power (200 W). This synthetic methodology provides easier separation of products and the catalyst exhibits recycling ability without loss of its catalytic activity up to five reaction cycles. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:267–271, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20197
Determination of Chitin and Protein Contents During the Isolation of Chitin from Shrimp Waste
Authors: Díaz‐Rojas Erika I. , Argüelles‐Monal Waldo M. , Higuera‐Ciapara Inocencio , Hernández Javier , Lizardi‐Mendoza Jaime , Goycoolea Francisco M. 
Published: May 2006

AbstractSummary: Accurate determination of chitin and protein contents in crustacean biomass and the intermediate products during the industrial isolation of chitin cannot be made directly from the total nitrogen content, unless the appropriate corrections are applied. This method, however, is affected by the presence of other nitrogen‐containing chemical species that are formed endogenously or by the action of microorganisms during the handling of the sample. Therefore, an alternative rapid method to estimate the contents of these components can be very useful both in research and in various fields of application. An original method has been developed to address this problem. The method consists of the development of a set of equations based on the stoichiometric contents of nitrogen of chitin and protein whereby the amounts of each component can be estimated from the value of the total nitrogen content, provided the rest of the proximate composition of the sample is accurately known. In order to validate the procedure, a set of model mixtures of pure chitin and protein concentrate in the solid state, both extracted from shrimp head waste, are used. Excellent agreement between the predicted and real values of chitin and protein are obtained (R2 = 0.98, slope = 0.90). When the proposed method is tested in the analysis of real samples obtained from five different processing protocols of pretreatment of raw shrimp head, it is found that in general the values of protein and chitin contents throughout the various stages of the process vary as expected.Variation of the measured total nitrogen versus calculated stoichiometric total nitrogen of the chitin‐protein mixtures.magnified imageVariation of the measured total nitrogen versus calculated stoichiometric total nitrogen of the chitin‐protein mixtures.
Reducing voxel bleed in hadamard‐encoded MRI and MRS
Authors: Goelman Gadi , Liu Songtao , Gonen Oded 
Published: May 2006

AbstractThe point spread function (PSF) of Hadamard encoding deviates from its ideal profile due to practical (as opposed to intrinsic) reasons. Finite radiofrequency (RF) pulse length and gradient strength cause slice profile imperfections that lead to cross‐talk (“voxel bleed”) as large as 17% for a 1‐KHz bandwidth, 5.12‐ms RF pulse under 3 mT/m. This could adversely affect localization and quantification, and consequently clinical usefulness. A simple modification of the Hadamard RF pulse synthesis that exploits its unique ability to encode noncontiguous slices is proposed and shown to markedly improve the PSF. Computer simulation, in vitro and in vivo experiments confirm the theoretical derivation of voxel bleed reduction from ∼17% to below 5% per Hadamard‐encoded direction. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Blipped multi gradient‐echo slice excitation profile imaging (bmGESEPI) for fast T measurements with macroscopic B0 inhomogeneity compensation
Authors: Truong Trong‐Kha , Chakeres Donald W. , Scharre Douglas W. , Beversdorf David Q. , Schmalbrock Petra 
Published: May 2006

AbstractWith the rapid development of human MRI at field strengths ≥ 7 T, knowledge of T relaxation times at such field strengths is needed to optimize acquisition parameters and understand relaxation mechanisms in many applications. However, standard T measurements (e.g., using conventional multiecho gradient‐echo (GE) sequences) are affected by macroscopic static magnetic field (B0) inhomogeneities, which are particularly severe at high field strength. The multi‐GE slice excitation profile imaging (mGESEPI) method was developed for T measurements in the presence of macroscopic B0 inhomogeneity, but it requires excessive acquisition times at field strengths ≥ 7 T. In this paper a more efficient technique, named blipped mGESEPI (bmGESEPI), is proposed. To demonstrate its advantages, T maps were acquired using a conventional multiecho GE method, the mGESEPI method, and the bmGESEPI method in postmortem and in vivo human brains at 8 T. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Continuous antibiotic infusion for salvage therapy of partially implanted central venous catheter tunnel infections due to staphylococci
Authors: Giacchino M. , Bezzio S. , Chiapello N. , Saracco P. , Fagioli F. , Caviglia I. , Moroni C. , Castagnola E. 
Published: May 2006

AbstractTunnel infection is an uncommon but serious complication observed in patients with partially implanted central venous catheters. International guidelines suggest that should include antibiotics and catheter removal. A success rate of only 5–20% was reported without catheter removal. We treated 13 episodes of tunnel Gram‐positive bacterial infection occurring in pediatric patients with cancer or serious blood disorders with 24‐hr intra‐catheter antibiotic continuous infusion. This approach led to a 69% success rate. Continuous infusion might be an attractive option to treat tunnel Gram‐positive bacterial infections when catheter removal might not be feasible or advisable. Pediatr Blood Cancer 2007;49:1010–1012. © 2006 Wiley‐Liss, Inc.
Prenatal diagnosis of a de novo complex chromosome rearrangement (CCR) mediated by six breakpoints, and a review of 20 prenatally ascertained CCRs
Authors: Giardino D. , Corti C. , Ballarati L. , Finelli P. , Valtorta C. , Botta G. , Giudici M. , Grosso E. , Larizza L. 
Published: May 2006

AbstractObjectivesTo describe the cytogenetic and FISH characterization of a prenatally diagnosed de novo complex chromosome rearrangement (CCR), showing the involvement of four chromosomes and six breakpoints, and review the literature concerning prenatally detected CCRs in order to obtain insights into addressing karyotype‐phenotype correlations in prenatal genetic counseling.MethodsConventional protocols were used to set up cultures and chromosome preparations. Commercial and homemade probes were used for the FISH analyses.ResultsAn apparently balanced de novo t(4;10;20) was prenatally identified by means of cytogenetic analysis. FISH revealed a rearrangement mediated by six breakpoints and the insertion of chromosome 8 material within the 4q region. The pregnancy was interrupted. The fetus showed malformations and anomalous cortical neuron migration. The assembled list of 20 prenatally detected CCRs points to the preferential involvement of chromosomes 4, 6 and 14. The involvement of chromosome 20 is described here for the first time.ConclusionsFISH analysis is essential for the accurate definition of a complex rearrangement. Phenotype description of fetuses carrying CCRs investigated by means of molecular cytogenetic techniques may contribute to improving and personalizing genetic counseling in prenatal diagnosis. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of TiO2–SiO2/polymer core–shell microspheres with a microphase‐inversion method
Authors: Xu Peng , Wang Haitao , Lv Rui , Du Qiangguo , Zhong Wei , Yang Yuliang 
Published: May 2006

AbstractA novel microphase‐inversion method was proposed for the preparation of TiO2–SiO2/poly(methyl methacrylate) core–shell nanocomposite particles. The inorganic–polymer nanocomposites were first synthesized via a free‐radical copolymerization in a tetrahydrofuran solution, and the poor solvent was added slowly to induce the microphase separation of the nanocomposite and result in the formation of nanoparticles. The average particle sizes of the microspheres ranged from 70 to 1000 nm, depending on the reaction conditions. Transmission electron microscopy and scanning electron microscopy indicated a core–shell morphology for the obtained microspheres. Thermogravimetric analysis and X‐ray photoelectron spectroscopy measurements confirmed that the surface of the nanocomposite microspheres was polymer‐rich, and this was consistent with the core–shell morphology. The influence of the synthetic conditions, such as the inorganic composition and the content of the crosslinking monomer, on the particle properties was studied in detail. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3911–3920, 2006
Thermodynamic stability of In1–x –yGax Aly N on GaN and InN
Authors: Kangawa Yoshihiro , Kakimoto Koichi , Ito Tomonori , Koukitu Akinori 
Published: May 2006

AbstractWe studied the thermodynamic stability of InGaAlN alloy based on calculations of enthalpy of mixing using empirical interatomic potentials. We also investigated the influence of lattice constraint from the bottom layer, i.e., (0001)GaN or (0001)InN, on thermodynamic stability of InGaAlN thin films. The results suggest that the maximum point of enthalpy of mixing shifted toward the In‐rich side in the case of InGaAlN/GaN and toward the In‐poor side in the case of InGaAlN/InN compared with that of bulk In1–x–yGaxAlyN at x = 0, y = 0.5. This implies that lattice constraint from the bottom layer has a significant influence on thermodynamic stability of thin films. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of epitaxial layer crystal quality on DC and RF characteristics of AlGaN/GaN short‐gate HEMTs
Authors: Shiojima K. , Makimura T. , Maruyama T. , Suemitsu T. , Shigekawa N. , Hiroki M. , Yokoyama H. 
Published: May 2006

AbstractThe DC and RF performances of short‐gate AlGaN/GaN high‐electron transistors (HEMT) on SiC and sapphire substrates have been investigated. There were differences in surface morphology, electron mobility, and contact resistance between SiC and sapphire wafers. The contact resistance limited and dispersed measured transconductance (gm). The intrinsic gm after subtraction of the source resistance contribution and gate‐length dependences of cut‐off frequency were the same. These results indicates that the effective electron velocity is the same for both samples. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low‐frequency noise in AlGaN/GaN HEMT structures with AlN thin film layer
Authors: Vitusevich S. A. , Antoniuk O. A. , Petrychuk M. V. , Danylyuk S. V. , Kurakin A. M. , Belyaev A. E. , Klein N. 
Published: May 2006

AbstractLow‐frequency noise in AlGaN/GaN high electron mobility transistor (HEMT) heterostructures with additional AlN thin barrier layer is investigated. Transmission line model structures with different lengths of the conducting channel formed by polarization effects at the heterointerface of undoped AlGaN/AlN/GaN layers are studied. The measured noise demonstrates an unusual broadening of the generation‐recombination components of the spectra. To explain the noise behaviour of the structure we consider a model taking into account peculiarities of the band structure of the interface with inserted AlN high molar fraction barrier layer. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of ternary and quaternary cubic III‐nitrides on 3C‐SiC substrates
Authors: Schörmann J. , Potthast S. , Schnietz M. , Li S. F. , As D. J. , Lischka K. 
Published: May 2006

AbstractCubic GaN, AlxGa1–xN/GaN multiple quantum wells and quaternary AlxGayIn1–x–yN layers were grown by plasma assisted molecular beam epitaxy on 3C‐SiC substrates. Using the intensity of a reflected high energy electron beam as a probe optimum growth conditions of c‐III nitrides were found, when a 1 monolayer Ga coverage is formed at the growing surface. Clear RHEED oscillations during the initial growth of AlxGa1–xN/GaN quantum wells were observed. X‐ray diffraction measurements of these quantum well structures show clear satellite peaks indicating smooth interfaces. Growth of quaternary AlxGayIn1–x–yN lattice matched to GaN were demonstrated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TEM analysis of annihilation process of threading dislocations in GaN thin films grown by MOVPE with anti‐surfactant treatment
Authors: Hijikuro M. , Kuwano N. , Takeuchi M. , Aoyagi Y. 
Published: May 2006

AbstractTransmission electron microscope (TEM) observation was performed for the anti‐surfactant (AS) treated GaN layer in order to clarify the annihilation process of dislocations. The morphology of dislocations in 3‐dimension was analyzed in a stereographical way by using a high‐voltage TEM. It was revealed that most of the threading dislocations are laid down on the AS‐treated surface and merge with one another to form a network of dislocations (sweep‐up process). The dislocations then decrease in number after the merging by cancellation of their Burgers vectors. It was also revealed that a thin layer is formed on the AS‐treated surface. The layer was confirmed to be crystalline. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InGaN quantum well epilayers morphological evolution under a wide range of MOCVD growth parameter sets
Authors: Florescu D. I. , Ting S. M. , Merai V. N. , Parekh A. , Lee D. S. , Armour E.A. , Quinn W. E. 
Published: May 2006

AbstractThis study exemplifies the use of TappingModeTM atomic force microscopy (AFM) surface morphology imaging to investigate and optimise the metalorganic chemical vapour deposition (MOCVD) growth conditions and post‐growth stability of thin (<40 Å) InGaN layers with direct implications to the structural and optical properties of blue (460 nm) and green (520 nm) LEDs. InGaN epilayers less than 40 Å thick of ∼20% solid phase indium were produced on thick (3‐4 µm) 2″ GaN templates grown on (0001) c ‐plane sapphire substrates. The morphological evolution of the InGaN material was studied utilising a DI3100 AFM tool. Surface morphology and its correlation with photoluminescence and X‐ray diffraction results will be discussed for every set of conditions employed. More specifically, the post‐growth ambient exposure and thermal stability of the uncapped InGaN epilayers were investigated. In addition, the initial stage of subsequent GaN growth, which is an essential step towards the manufacture of LED active regions, was examined. Based on the above findings, a flexible MOCVD growth parameter space and improved LED constituent layer sequencing techniques have been established leading to more efficient and stable LED devices. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐EL studying of high power blue LEDs
Authors: Onushkin G. A. , Zakgeim A. L. , Zakgeim D. A. , Rozhansky I. V. , Tsatsulnikov A. F. , Lundin W. V. , Sizov D. S. 
Published: May 2006

AbstractThe micro electro‐luminescence (EL) investigation of high‐power blue flip‐chip LEDs at high currents has been performed. The studied distribution of the spectral EL characteristics over the LED emitted area allowed evaluating the current crowding effect and revealed the local overheating of the p‐n junction. The current crowding effect lead to the two times higher local EL intensity. The local p‐n junction temperature distribution was calculated from FWHM map using obtained value a FWHM temperature coefficient. Maximum local junction temperature was by 50 K higher than average value over the LED area. The high local temperature and high local current density can lead to device failure or drastically decreases the LED lifetime. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of celery (Apium graveolens) extracts on some biochemical parameters of oxidative Stress in mice treated with carbon tetrachloride
Authors: Popović Mira , Kaurinović Biljana , Trivić Svetlana , Mimica‐Dukić Neda , Bursać Marija 
Published: May 2006

AbstractExtracts of celery leaves and roots in ether, chloroform, ethyl acetate, n‐butanol and water were evaporated to dryness and dissolved in 50% ethanol to make 10% (w[sol ]v) solutions. The potential protective action of the extracts was assessed by the corresponding in vitro and in vivo tests. In the in vitro experiments crude methanol extracts were tested as potential scavengers of free OH• and DPPH• radicals, as well as inhibitors of liposomal peroxidation (LPx). Analogous experiments were also carried out with the extracts of celery root, for comparison. The results obtained show that both the extracts of root and leaves are good scavengers of OH• and DPPH• radicals and reduce LPx intensity in liposomes, which points to their protective (antioxidant) activity. In vivo experiments were concerned with antioxidant systems (activities of GSHPx, GSHR, Px, CAT, XOD, GSH content and intensity of LPx) in liver homogenate and blood of mice after their treatment with extracts of celery leaves, or in combination with CCl4. On the basis of the results obtained it can be concluded that the examined extracts showed a certain protective effect. Of all the extracts the n‐butanol extract showed the highest protective effect. Combined treatments with CCl4 and extracts showed both positive and negative synergism – inducing or suppressing the impact of CCl4 alone. The differences observed in the action of particular extracts are probably due to the different contents of flavonoids and some other antioxidant compounds. Copyright © 2006 John Wiley & Sons, Ltd.
Isolation of flavonoids, a biscoumarin and an amide from the flower buds of Daphne genkwa and the evaluation of their anti‐complement activity
Authors: Park Bo‐Young , Min Byung‐Sun , Oh Sei‐Ryang , Kim Jung‐Hee , Bae Ki‐Hwan , Lee Hyeong‐Kyu 
Published: May 2006

AbstractAs part of an ongoing study aimed at identifying the anti‐complement active compound from the flower buds of Daphne genkwa, ten flavonoids, one biscoumarin and one amide were isolated. Their structures were identified from spectroscopic and physicochemical data as genkwanin 5‐O‐β‐d‐primveroside (1), apigenin 7‐O‐β‐d‐glucuronide (2), genkwanin 5‐O‐β‐d‐glucopyranoside (3), apigenin 5‐O‐β‐d‐glucopyranoside (4), genkwanin (5), apigenin (6), luteolin 7‐methyl ether (7), luteolin (8), daphnoretin (9), velutin (10), 7‐methoxyacacetin (11) and aurantiamide acetate (12). Among them, compounds 9, 10 and 12 were isolated from this plant for the first time. The anti‐complement activity of these compounds was tested against the classical pathway of the complement system. Among the compounds, daphnoretin (9) exhibited significant anti‐complement activity with an IC50 value of 11.4 µm, whereas the other compounds were not active in the assay. Copyright © 2006 John Wiley & Sons, Ltd.
Relationship between individual DNA methylation percentage differences and carcass traits in pigs
Authors: Cao-De Jiang , Chang-Yan Deng , Yuan-Zhu Xiong 
Published: May 2006

AbstractIn order to investigate the effects of DNA methylation on pig carcass traits, the methylation-sensitive amplified polymorphism technique (MSAP) was adopted to amplify DNA from blood samples taken from 77 F1hybrids of Large White×Meishan crosses. A total of 15 carcass traits were tested. Results showed that means of internal fat rate (IFR), lean meat percentage (LMP) and ratio of lean meat versus fat meat (RLF) were significantly different (P<0.05) among five levels of general individual methylation difference (GIMDP); means of carcass weight (CW), IFR, backfat thickness at buttock (BFT3), average backfat thickness (ABF), carcass length to the first rib (CLR) and carcass length to the first neck vertebra (CLN) were also significantly different (P<0.05) among five levels of special individual methylation percentage difference (SIMDP), while means of 15 carcass traits were not significantly different (P>0.05) among five levels of neutral individual methylation percentage difference (NIMDP). Of all traits that were significantly affected by SIMPD, CW, ABF and BFT3increased, IFR and backfat thickness at shoulder (BFT1) decreased, while CLR and bone percentage (BP) fluctuated with the SIMDP increase. The regressions between SIMDP and IFR, BFT1, BFT3and ABF were significant (P<0.05). It is concluded that DNA methylation can be applied as a marker to related studies in pigs; positive methylation sites were superior to negative methylation sites in predicting hybrid performance, and methylation differences should be maintained at specific levels for different traits to improve the productivity of pigs.
An association between tyrosinase gene single nucleotide polymorphisms and melanin distribution in chicken
Authors: Zhi-Qiang Chen , Xue-Mei Deng , Jun Zhou , Ning Li , Chang-Xin Wu 
Published: May 2006

AbstractTyrosinase (TYR) is a key enzyme of melanin biosynthesis. Single-strand conformation polymorphism (SSCP) analysis was applied to detect the single nucleotide polymorphisms (SNPs) in the upstream regulating region from -641 to -2125 bp of the TYR gene. Three SNPs were found in this region. Correlations were obtained between genotypes of the SNP sites and pigment traits in chicken parental and F2 generations of the Chinese Agricultural University (CAU) resource population. The chi-square test indicated that these mutations were significantly related to shank and body skin colours.