bluuebunny/crossref_metadata_2025 huggingface dataset:
Bone mineral density deficits in pediatric patients treated for sarcoma
Authors: Kaste Sue C. , Ahn Hyunah , Liu Tiebin , Liu Wei , Krasin Matthew J. , Hudson Melissa M. , Spunt Sheri L.
Published: June 2007

Background

Children treated for sarcoma are at risk of treatment‐associated deficits in bone mineral density (BMD). We investigated the severity of risk factors for BMD deficits in this patient population.

Procedure

Using signed‐rank test and logistic regression analysis, we retrospectively analyzed the relation of treatment variables and other potential risk factors to BMD (using quantitative computed tomography (QCT)) of 99 patients treated for pediatric sarcoma who had completed therapy at least 1 year previously.

Results

The study group (38% rhabdomyosarcoma (RMS), 25% osteosarcoma (OS), 24% Ewing‐family tumors, and 12% non‐rhabdomyosarcoma soft‐tissue sarcoma (NRSTS)) represented 22% of the sarcoma survivors treated between 1982 and 2003 who remained in follow‐up at St. Jude. These patients underwent QCT between July 1, 1997 and February 5, 2003. Their median age was 8.7 years (range, 0.2–21.3 years) at diagnosis and 17.4 years (range, 3.3–30.2 years) at the time of BMD measurement; 58% were male and 82% Caucasian. Median BMD Z‐score was −0.75 (range, −3.33–3.02), and median BMD was 168.0 mg/cc (range, 89.2–264.8 mg/cc). Risk of BMD deficit increased significantly with younger age at diagnosis (P = 0.044) and higher cumulative cyclophosphamide dose (P = 0.007). Patients with lower extremity primary disease had a significantly lower risk of BMD deficits than others. We found no association between BMD and body habitus, primary disease, lifestyle factors, or endocrinopathy.

Conclusion

A significant subset of sarcoma survivors are at risk of BMD deficits warranting prospective study of BMD to verify our results and refine risk factors contributing to BMD deficits. Pediatr Blood Cancer 2008;50:1032–1038. © 2007 Wiley‐Liss, Inc.
Investigation of liquid crystalline and photocrosslinkable poly[4‐x‐phenyl‐4′‐(m‐methacryloyloxyalkyloxy)cinnamate]s
Authors: Mohan Kumar Rajayyan , Balamurugan Rathinam , Kannan Palaninathan
Published: June 2007

Three series of liquid‐crystalline‐cum‐photocrosslinkable polymers were synthesized from 4‐x‐phenyl‐4′‐(m‐methacryloyloxyalkyloxy)cinnamates (x = − H, OCH3 and CN; m = 6, 8 and 10) by free radical solution polymerization using azobisisobutyronitrile as an initiator in tetrahydrofuran at 60 °C. All the monomers and polymers were characterized using intrinsic viscosity, and FTIR, 1H NMR and 13C NMR spectroscopy. The liquid crystalline behavior of these polymers was examined using a hot stage optical polarizing microscope. All the polymers exhibited liquid crystalline behavior. The hexamethylene spacer‐containing polymers exhibited grainy textures; in contrast, the octamethylene and decamethylene spacer‐containing polymers showed nematic textures. Differential scanning calorimetry data confirmed the liquid crystalline property of the polymers. Thermogravimetric analysis revealed that all the polymers were stable between 236 and 344 °C in nitrogen atmosphere and underwent degradation thereafter. As the methylene chain length increases in the polymer side‐chain, the thermal stability and char yield of the polymers decrease. The photocrosslinking property of the polymers was investigated using the technique of exposing the polymer solution to UV light and using UV spectroscopy. The crosslinking reaction proceeds via 2π–2π cycloaddition reactions of the CHCHof the pendant cinnamate ester. The polymers containing electron‐releasing substituents (OCH3) showed faster crosslinking than the unsubstituted polymers and those containing electron‐withdrawing substituents (CN). Copyright © 2007 Society of Chemical Industry
Structure and properties of the polyelectrolyte complex of chitosan with poly(methacrylic acid)
Authors: Chen Shilan , Liu Mingzhu , Jin Shuping , Chen Yong
Published: June 2007

The structure and properties of the polyelectrolyte complex composed of chitosan (CS) and poly(methacrylic acid) (PMAA) were studied in aqueous solutions using UV‐visible transmittance measurements, a fluorescence probe technique, and transmission electron microscopy. The thermal properties of the solid complex were measured using differential scanning calorimetry. The results showed that the complex optimum molar ratio (in monomer unit) of CS to PMAA is 1:4 at pH = 4.0, that is, there is an optimum complex between CS and PMAA when the feed ratio (in molar monomer unit) of CS to PMAA is 1:4 and an ionic bond between the amino ion group and carboxylate group can be formed on average every four carboxylate (or carboxyl) groups. The conformation of PMAA changed from a hypercoiled to a loose coil on complexation, and the pH‐ and salt‐sensitive range of the polyelectrolyte complex was obviously different from that of CS or PMAA. The formation process of the complex under various external conditions is discussed in detail. Transmission electron microscopy revealed that the sizes of CS–PMAA complex particles increased with increasing pH or salt concentration, and a change in morphology of the complex was observed. Thermal analysis further revealed that there was a change of structure and properties on blending in aqueous solutions. Copyright © 2007 Society of Chemical Industry
Synthesis, characterization and thermal dissociation of 2‐butoxyethanol‐blocked diisocyanates and their use in the synthesis of isocyanate‐terminated prepolymers
Authors: Ahmad Iftikhar , Zaidi Javid H , Hussain Rizwan , Munir Arshad
Published: June 2007

A series of blocked diisocyanates has been synthesized from toluene diisocyante (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 4,4′‐diphenylmethane diisocyanate (MDI) and 2‐butoxyethanol. The synthesis of blocked diisocyanate adducts was confirmed by Fourier transform infrared, 1H NMR, electron impact mass spectrometry and nitrogen analysis. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and carbon dioxide evolution were used to determine the minimum de‐blocking temperatures. De‐blocking temperatures determined by these three techniques were found to be in the order DSC > TGA > CO2 evolution. The effect of different metal catalysts on thermal de‐blocking reaction of the blocked diisocyanates was studied, using the carbon dioxide evolution method. It was found that iron(III) oxide has the maximum catalytic activity on de‐blocking. The solubility of the blocked diisocyanate adducts was determined in different solvents. The study revealed that at 30 °C blocked IPDI and HDI adducts show better solubility than adducts based on TDI and MDI. Isocyanate‐terminated prepolymers of blocked diisocyanates and hydroxyl‐terminated polybutadiene (HTPB) were prepared. The storage stability and gelation times of the prepolymers were studied. Results showed that all the diisocyanate‐HTPB compositions are stable at 50 °C for more than three months. However, aliphatic diisocyanate‐HTPB compositions require greater gelation time than aromatic diisocyanate‐HTPB compositions at their respective de‐blocking temperatures. Copyright © 2007 Society of Chemical Industry
Proteomic analysis of de‐etiolated rice seedlings upon exposure to light
Authors: Yang Pingfang , Chen Hui , Liang Yu , Shen Shihua
Published: June 2007

Two‐week‐old dark‐grown rice seedlings were de‐etiolated upon exposure to light. A comparison of 2‐DE protein profiles between the dark‐grown control and the rice seedlings illuminated respectively for 6, 12 and 24 h revealed 52 differentially expressed CBB‐stained spots. Of these changed spots, the identity of 51 protein spots was determined by MALDI‐TOF MS. Of these identified proteins, 13 proteins were related to light reactions of photosynthesis, photosynthetic carbon assimilation and chlorophyll biosynthesis, indicating the complex process of biogenesis of photosynthetic apparatus was correlated to the transition from a dark‐grown (etiolated) to a light‐grown (de‐etiolated) morphology. In addition, three proteins related to antioxidation and detoxification decreased in de‐etiolated rice seedlings implied, that the etiolated rice seedlings possibly be under an oxidative stress which could be released during their early stages of de‐etiolation. The increase of S‐adenosylmethionine synthetase that is involved in the biosynthesis of the phytohormone ethylene might contribute to the phenotypic development of the apical hook in the de‐etiolated rice seedlings. These results yield a comprehensive picture of the post‐transcriptional response for de‐etiolation of rice seedlings and serve as a basic platform for further characterization of gene function and regulation in light‐induced development of plants.
Proteome analysis of human androgen‐independent prostate cancer cell lines: Variable metastatic potentials correlated with vimentin expression
Authors: Wu Mingfu , Bai Xiangyang , Xu Gang , Wei Juncheng , Zhu Tao , Zhang Yongtao , Li Qiong , Liu Ping , Song Anping , Zhao Liangpin , Gang Chen , Han Zhiqiang , Wang Shixuan , Zhou Jianfeng , Lu Yunpin , Ma Ding
Published: June 2007

To better understand the molecular mechanisms of prostate cancer (PCA) dissemination and to develop new anti‐metastasis therapies, key regulatory molecules involved in PCA metastasis were identified in two human androgen‐independent PCA cell lines, highly metastatic 1E8‐H and lowly metastatic 2B4‐L cells. Through 2‐DE and MS analyses, 12 proteins with different expression levels in the two cell lines were identified. The following proteins were found to be significantly up‐regulated in 1E8‐H cells compared with 2B4‐L cells: gp96 precursor, calreticulin precursor, vimentin (VIM), Hsp90α, peroxiredoxin 2, HNRPH1, ezrin, T‐complex protein 1, alpha subunit, and hypothetical protein mln2339. In contrast, heart L‐lactate dehydrogenase H chain, annexin I, and protein disulfide isomerase were notably down‐regulated in 1E8‐H cells compared with 2B4‐L cells. To our knowledge, this study is the first to demonstrate that up‐regulation of VIM expression positively correlates with the invasion and metastasis of androgen‐independent PCA.
Qualitative and comparative proteomic analysis of Xanthomonas campestris pv. campestris 17
Authors: Chung Wei‐Jen , Shu Hung‐Yu , Lu Chi‐Yu , Wu Chiu‐Yi , Tseng Yi‐Hsiung , Tsai Shih‐Feng , Lin Chao‐Hsiung
Published: June 2007

The bacterium Xanthomonas campestris pathovar campestris (XCC) 17 is a local isolate that causes crucifer black rot disease in Taiwan. In this study, its proteome was separated using 2‐DE and the well‐resolved proteins were excised, trypsin digested, and analyzed by MS. Over 400 protein spots were analyzed and 281 proteins were identified by searching the MS or MS/MS spectra against the proteome database of the closely related XCC ATCC 33913. Functional categorization of the identified proteins matched 141 (50%) proteins to 81 metabolic pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. In addition, we performed a comparative proteome analysis of the pathogenic strain 17 and an avirulent strain 11A to reveal the virulence‐related proteins. We detected 22 up‐regulated proteins in strain 17 including the degrading enzymes EngXCA, HtrA, and PepA, which had been shown to have a role in pathogenesis in other bacteria, and an anti‐host defense protein, Ohr. Thus, further functional studies of these up‐regulated proteins with respect to their roles in XCC pathogenicity are suggested.
Phosphoproteomics identified Endofin, DCBLD2, and KIAA0582 as novel tyrosine phosphorylation targets of EGF signaling and Iressa in human cancer cells
Authors: Chen Yunhao , Low Teck‐Yew , Choong Lee‐Yee , Ray Rajarshi Sankar , Tan Yee‐Ling , Toy Weiyi , Lin Qingsong , Ang Boon Keong , Wong Chee Hong , Lim Simin , Li Bin , Hew Choy‐Leong , Sze Newman Siu‐Kwan , Druker Brian J. , Lim Yoon‐Pin
Published: June 2007

With the completion of the human genome project, analysis of enriched phosphotyrosyl proteins from epidermal growth factor (EGF)‐induced phosphotyrosine proteome permits the identification of novel downstream substrates of the EGF receptor (EGFR). Using cICAT‐based LC‐MS/MS method, we identified and relatively quantified the tyrosine phosphorylation levels of 21 proteins between control and EGF‐treated A431 human cervical cancer cells. Of these, Endofin, DCBLD2, and KIAA0582 were validated to be novel tyrosine‐phosphorylation targets of EGF signaling and Iressa, a highly selective inhibitor of EGFR. In addition, EGFR activity was shown to be necessary for EGF‐induced localization of Endofin, an FYVE domain‐containing protein regulated by phosphoinositol lipid and engaged in endosome‐mediated receptor modulation. Although several groups have conducted phosphoproteomics of EGF signaling in recent years, our study is the first to identify and validate Endofin, DCBLD2, and KIAA0582 as part of a complex EGF phosphotyrosine signaling network. These novel data will provide new insights into the complex EGF signaling and may have implications on target‐directed cancer therapeutics.
The PSI formal document process and its implementation on the PSI website
Authors: Vizcaíno Juan Antonio , Martens Lennart , Hermjakob Henning , Julian Randall K. , Paton Norman W.
Published: June 2007

The Human Proteome Organisation's Proteomics Standards Initiative (HUPO‐PSI) has recently developed formal document processes for reviewing MIAPE documents, specifications, community practice and informational documents. These document workflows rely on community participation as well as more traditional expert review. We here present the web interface used to support these document processes, and explain briefly how interested parties can participate in the review process. The HUPO‐PSI website can be found at http://www.psidev.info.
Computational approach for identification and characterization of GPI‐anchored peptides in proteomics experiments
Authors: Omaetxebarria Miren J. , Elortza Felix , Rodríguez‐Suárez Eva , Aloria Kerman , Arizmendi Jesus M. , Jensen Ole N. , Matthiesen Rune
Published: June 2007

Genes that encode glycosylphosphatidylinositol anchored proteins (GPI‐APs) constitute an estimated 1–2% of eukaryote genomes. Current computational methods for the prediction of GPI‐APs are sensitive and specific; however, the analysis of the processing site (ω‐ or omega‐site) of GPI‐APs is still challenging. Only 10% of the proteins that are annotated as GPI‐APs have the ω‐site experimentally verified. We describe an integrated computational and experimental proteomics approach for the identification and characterization of GPI‐APs that provides the means to identify GPI‐APs and the derived GPI‐anchored peptides in LC‐MS/MS data sets. The method takes advantage of sequence features of GPI‐APs and the known core structure of the GPI‐anchor. The first stage of the analysis encompasses LC‐MS/MS based protein identification. The second stage involves prediction of the processing sites of the identified GPI‐APs and prediction of the corresponding terminal tryptic peptides. The third stage calculates possible GPI structures on the peptides from stage two. The fourth stage calculates the scores by comparing the theoretical spectra of the predicted GPI‐peptides against the observed MS/MS spectra. Automated identification of C‐terminal GPI‐peptides from porcine membrane dipeptidase, folate receptor and CD59 in complex LC‐MS/MS data sets demonstrates the sensitivity and specificity of this integrated computational and experimental approach.
A novel method for analyzing phosphoproteins using SELDI‐TOF MS in combination with a series of recombinant proteins
Authors: Akashi Tetsuyuki , Yamori Takao
Published: June 2007

A novel SELDI‐TOF MS‐based method for analyzing phosphoproteins was developed using a series of recombinant wild‐type and mutant ribosomal P2 proteins. We demonstrated that the phosphorylation status of the overexpressed proteins in cells was easily and rapidly confirmed using this method. The ribosomal P2 protein contained two phosphorylation sites, which were sequentially phosphorylated in vivo. We also quantitatively detected the phosphoprotein by using SELDI‐TOF MS.
Diagnostic biomarkers differentiating metastatic melanoma patients from healthy controls identified by an integrated MALDI‐TOF mass spectrometry/bioinformatic approach
Authors: Matharoo‐Ball Balwir , Ratcliffe Lucy , Lancashire Lee , Ugurel Selma , Miles Amanda K. , Weston Daniel J. , Rees Robert , Schadendorf Dirk , Ball Graham , Creaser Colin S.
Published: June 2007

The prognosis of advanced metastatic melanoma (American Joint Committee on Cancer (AJCC) stage IV) remains dismal with a 5‐year survival rate of 6–18%. In the present study, an integrated MALDI mass spectrometric approach combined with artificial neural networks (ANNs) analysis and modeling has been used for the identification of biomarker ions in serum from stage IV melanoma patients allowing the discrimination of metastatic disease from healthy status with high specificities of 92% for protein ions and 100% for peptide biomarkers. Our ANNs model also correctly classified 98% of a blind validation set of AJCC stage I melanoma samples as nonstage IV samples, emphasizing the power of the newly defined biomarkers to identify patients with late‐stage metastatic melanoma. Sequence analysis identified peptides derived from metastasis‐associated proteins; alpha 1‐acid glycoprotein precursor‐1/2 (AAG‐1/2) and complement C3 component precursor‐1 (CCCP‐1). Furthermore, quantitation of serum AAG by an immunoassay showed a significant (p<0.001) increase in AAG serum concentration in stage IV patients in comparison with healthy volunteers; moreover; the quantity of AAG plotted against MALDI‐MS peak intensity classified the groups into two distinct clusters. Ongoing studies of other disease stages will provide evidence whether our strategy is sufficiently robust to give rise to stage‐specific protein/peptide signatures in melanoma.
Special Materials in Pyrotechnics: VI. Silicon – An Old Fuel with New Perspectives
Authors: Koch Ernst‐Christian , Clément Dominik
Published: June 2007

The application of silicon as fuel in common pyrotechnic and explosive compositions is reviewed. For part V see Ref. [56].
On the Oxidation and Combustion of AlH3 a Potential Fuel for Rocket Propellants and Gas Generators
Authors: Weiser Volker , Eisenreich Norbert , Koleczko Andreas , Roth Evelin
Published: June 2007

Aluminum hydride is a promising candidate for application in energetic materials and hydrogen storages. E.g. an AP/HTPB rocket propellant filled with alane was calculated for a 100 N s kg−1 higher specific impulse compared to the same concentration of aluminum. Different investigations on α‐AlH3 polyhedra using thermoanalytical methods and X‐ray diffraction were performed to receive a better understanding of dehydration at about 450 K, passivation of the remaining porous aluminum particles and further oxidation. A modeling approach to describe these conversions including diffusion processes, Avrami‐Erofeev mechanism and Arrhenius type reaction steps of n‐th order were introduced. Results were discussed in comparison to experimental investigations under pressure with model propellants on the base of gelled pure nitromethane and also filled with alane or pure aluminum in concentrations of 5%, 10% and 15%. Both alane and aluminum increase the burning rate on a factor of two correlated with a temperature increase up to 500 K and more. A mesa burning effect at 6 to 10 MPa was indicated by the mixtures with alane.
The Interaction between Otto Fuel II and Aqueous Hydroxylammonium Perchlorate (HAP), Part III: Depletion of Components within the Reacting Liquids
Authors: Bellerby John M. , Blackman Christopher S.
Published: June 2007

Gas chromatography (GC) with a Flame Ionisation Detector (FID) has been used to determine changes in the concentrations of the components of Otto Fuel II (OF) in contact with an 82% aqueous solution of hydroxylammonium perchlorate (HAP) in sealed vials at 31.7 °C during the period leading up to auto‐ignition of the two liquids. The concentration of hydroxylamine in HAP was monitored over the same period using a titration method. It was found that 2‐nitrodiphenylamine (2NDPA), the stabiliser in the OF, is completely consumed after about 65–70 h and that the concentration of hydroxylamine begins to fall at this point. 1,2‐Propanediol dinitrate (propylene glycol dinitrate, PGDN), the energetic component in the OF, is not depleted significantly until after about 90 h. The evolution of nitrous oxide (N2O) between 65 and 90 h is attributed to the reaction of the hydroxylammonium ion with nitrous acids produced by PGDN decomposition at the liquid‐liquid interface. Carbon dioxide (CO2) is evolved after ~ 90 h and is attributed to PGDN decomposition. HAP and PGDN are each thought to contribute to N2O evolution after ~ 90 h.
Synthesis and Characterization of 3,4,5‐Triamino‐1,2,4‐Triazolium 5‐Nitrotetrazolate
Authors: Darwich Chaza , Klapötke Thomas M. , Welch Jan M. , Suceska Muhamed
Published: June 2007

3,4,5‐Triamino‐1,2,4‐triazolium 5‐nitrotetrazolate (2) was synthesized in high yield from 3,4,5‐triamino‐1,2,4‐triazole (guanazine) (1) and ammonium 5‐nitrotetrazolate. The new compound 2 was characterized by vibrational (IR and Raman) and multinuclear NMR spectroscopy (1H, 13C, 15N), elemental analysis and single crystal X‐ray diffraction (triclinic, P(‐1), a=0.7194(5), b=0.8215(5), c=0.8668(5) nm, α=75.307(5), β=70.054(5), γ=68.104(5)°, V=0.4421(5) nm3, Z=2, ϱ=1.722 g cm−1, R1=0.0519 [F>4σ(F)], wR2(all data)=0.1154). The 15N NMR spectrum and X‐ray crystal structure (triclinic, P‐1, a=0.5578(5), b=0.6166(5), c=0.7395(5) nm, α=114.485(5)°, β=90.810(5)°, γ=97.846(5)°, V=0.2286(3) nm3, Z=2, ϱ=1.658 g cm−1, R1=0.0460 [F>4σ(F)], wR2(all data)=0.1153) of 1 were also determined.
Shock Desensitization Effect in the Confined Explosive Component Water Gap Test Defined by the NATO Standardization Agreement (STANAG) 4363
Authors: Lefrançois Alexandre S. , Lee Ronald S. , Tarver Craig M.
Published: June 2007

In an effort to extend the modified explosive component water gap test [1–3] defined by the NATO standardization agreement (STANAG) 4363, several countries have investigated the shock sensitiveness of confined lead and booster components having a diameter less than 5 mm [4–8]. A pentaerythritol tetranitrate (PETN) based acceptor pellet is chosen as a reference with a height and diameter of 3 mm. The height of the steel confinement is equal to the one of the HE pellet and the wall thickness varies. A 1‐mm thick wall makes the component more sensitive (larger water gap). As the wall thickness is increased to 2‐mm, the gap increases a lesser amount. A decrease in sensitivity is observed with a 3.5 mm thick wall (smaller water gap). This decrease of the water gap has been reproduced experimentally. This unusual behavior remains puzzling and does not allow the test to be extended for small components. This work presents the numerical simulations performed with LS‐Dyna in 2D axi‐symmetrical and 3D wedge configurations, using an ignition and growth model [9] for LX‐16 (96% PETN, 4% FPC 461) in order to evaluate the shock sensitiveness for a confined HE acceptor.
Increased expression of CCAAT/enhancer‐binding protein beta in proliferative inflammatory atrophy of the prostate: Relation with the expression of COX‐2, the androgen receptor, and presence of focal chronic inflammation
Authors: Wang Wanzhong , Bergh Anders , Damber Jan‐Erik
Published: June 2007

BACKGROUND

Proliferative inflammatory atrophy (PIA) in the prostate has been proposed to be a precursor to prostate cancer. CCAAT/enhancer‐binding protein beta (C/EBPβ) is an important transcription factor involved in cellular proliferation and differentiation. Activation of C/EBPβ plays a crucial role during the initial stage of cyclo‐oxygenase 2 (COX‐2) induction by proinflammatory mediators. Overexpression of C/EBPβ has been reported in several human tumors. Nevertheless, the C/EBPβ expression and functions in human prostate tissue are basically unknown.

METHODS

C/EBPβ immunohistochemical staining was performed on 45 benign prostate hyperplasia (BPH) samples. The expression of C/EBPβ in PIA lesions and normal‐appearing acini was analyzed. In addition, by using double‐IHC staining, C/EBPβ expression and the association with chronic inflammatory cell density, co‐expression of COX‐2 and androgen receptor (AR) were also investigated.

RESULTS

C/EBPβ was occasionally observed in normal‐appearing prostate acini (4.9% ± 6.7%, Mean ± SD) but was clearly overexpressed in PIA lesions (81.8% ± 16.4%) (P < 0.0001). Atrophic glands with T‐lymphocyte and macrophage inflammation expressed higher level of C/EBPβ. Furthermore, C/EBPβ correlated significantly with COX‐2 expression. Downregulation of the AR was common in PIA and was also related to the C/EBPβ overexpression.

CONCLUSIONS

The data demonstrated that chronic inflammation appeared to play roles in the induction of C/EBPβ expression in prostate epithelium, which was in turn associated with increased COX‐2 expression and AR downregulation. In combining with other molecular alteration in the epithelium of PIA, it is suggested that these cells might be a kind of intermediate cells and involved in the pathogenesis of prostate cancer. Prostate 67: 1238–1246, 2007. © 2007 Wiley‐Liss, Inc.
Gene expression in pyriproxyfen‐ resistant Bemisia tabaci Q biotype
Authors: Ghanim Murad , Kontsedalov Svetlana
Published: June 2007

Pyriproxyfen is a biorational insecticide that acts as a juvenile hormone (JH) analogue and disrupts insect development with an unknown molecular mode of action. Pyriproxyfen is one of the major insecticides used to control the whitefly Bemisia tabaci (Gennadius) and comply with integrated pest management (IPM) programmes, resulting in minimal effects on the environment, humans and beneficial organisms. During the last few years, resistance to pyriproxyfen has been observed in several locations in Israel, sometimes reaching a thousandfold or more. No information exists about the molecular basis underlying this resistance that may lead to understanding the mode of action of pyriproxyfen and developing molecular markers for rapid monitoring of resistance outbreaks. In this communication, a cDNA microarray from B. tabaci was used to monitor changes in gene expression in a resistant B. tabaci population. Based on statistical analysis, 111 expressed sequence tags (ESTs) were identified that were differentially upregulated in the resistant strain after pyriproxyfen treatment. Many of the upregulated ESTs observed in the present study belong to families usually associated with resistance and xenobiotic detoxification such as mitochondrial genes, P450s and oxidative stress, genes associated with protein, lipid and carbohydrate metabolism and others related to JH‐associated processes in insects such as oocyte and egg development. Copyright © 2007 Society of Chemical Industry
Time‐dependent Ginzburg–Landau equations for a two‐band superconductor and the relaxation times of the order parameters in Y1–xCaxBa2Cu3O7–δ
Authors: Konsin P. , Sorkin B.
Published: June 2007

Time‐dependent Ginzburg–Landau equations for clean and dirty two‐band superconductors are derived. The general formulas for the relaxation times of the two‐component order parameter caused by interband scattering of the intraband pairs are obtained. The two relaxation times (τA and τB ) of the order parameters in Y1–x Cax Ba2Cu3O7–δ are calculated. Below the superconducting transition temperature Tc the calculation gives two distinct relaxation times, one with τB = 0.5 ps and the other with τA = 3 ps in the low temperature region in agreement with the experiment. The relaxation time τA possesses the critical behaviour. The other (noncritical) relaxation channel is characterized by almost T ‐independent relaxation time τB pointing to the existence of a T ‐independent pseudogap. The effects of impurities are taken into account. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relaxation and recombination in InAs quantum dots
Authors: Dawson P. , Göbel E. O. , Pierz K. , Rubel O. , Baranovskii S. D. , Thomas P.
Published: June 2007

In this paper we discuss recent developments in the study of the temperature dependence of the optical properties of InAs/GaAs quantum dots and the mechanisms involved in the relaxation and recombination from InAs/AlAs quantum dots. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intersubband absorption at 1.5–3.5 μm in GaN/AlN multiple quantum wells grown by molecular beam epitaxy on sapphire
Authors: Liu X. Y. , Holmström P. , Jänes P. , Thylén L. , Andersson T. G.
Published: June 2007

Ten and twenty period multiple quantum well structures with 1.5–5.4 nm GaN wells and 1.2–5.1 nm AlN barriers were grown on sapphire by molecular beam epitaxy. Layer thicknesses were determined by X‐ray diffraction measurements and simulations. Reciprocal space mapping showed that the relaxation of the quantum well layers was independent of the buffer layer thickness. Intersubband absorption was observed by Fourier transform infrared spectroscopy at λ ∼ 1.5–3.5 μm. Monolayer fluctuations in the quantum well width induced multiple peaks in spectra, which were well fitted to Lorentzian peaks of only 57 meV linewidth. Samples were very homogeneous as the absorption peak energy varied less than 1% along ∼4 cm on 2 inch wafers. The intersubband transition energies were calculated considering the conduction‐band nonparabolicity, built‐in fields, strain, and many‐body effects. The calculation and comparison to the fitted Lorentzian peak energies indicated a moderate blueshift due to many‐body effects. It was shown by both experiments and calculations that the AlN barrier width affects the intersubband transition energy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inelastic light scattering spectroscopy of semiconductor nitride nanocolumns
Authors: Calleja J. M. , Lazić S. , Sanchez‐Páramo J. , Agulló‐Rueda F. , Cerutti L. , Ristić J. , Fernández‐Garrido S. , Sánchez‐Garcia M. A. , Grandal J. , Calleja E. , Trampert A. , Jahn U.
Published: June 2007

A review of inelastic light scattering measurements on group III‐nitride nanocolumns grown by molecular beam epitaxy is presented. The nanocolumns are hexagonal, high quality single crystals with diameters in the range of 20 to 100 nm, with no traces of extended defects. GaN nanocolumns grown on bare Si substrates with both (111) and (100) orientation display narrow phonon peaks, indicating the absence of strain inhomogeneities. This opens the possibility of efficient integration of the nanocolumns as optoelectronic devices with the complementary metal oxide semiconductor technology. Measurements of theE2phonon frequency on AlGaN nanocolumns indicate a linear dependence of the Al concentration on the Al relative flux, up to 60%. TheE2peak width increases with Al content due to phonon damping by alloy scattering. Inelastic light scattering measurements in InN nanocolumns display a coupled LO phonon‐plasmon mode together with uncoupled phonons. The coupled mode is not observed in a reference compact sample. The origin of the coupled mode is attributed to spontaneous accumulation of electrons at the lateral surfaces of the nanocolumns. The presence of free electrons in the nanocolumns is confirmed by infrared reflectance measurements. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐organization and finite size effects in epitaxial ferromagnetic MnAs films on GaAs
Authors: Däweritz L. , Herrmann C.
Published: June 2007

The self‐organized striped structure of coexisting α‐MnAs and β‐MnAs, characteristic for MnAs films grown on GaAs(001) by molecular beam epitaxy under As‐rich conditions at low temperature, has been studied in samples prepared under conditions closer to the equilibrium. Whereas the period of the stripe pattern is independent on the preparation procedure, the width of the ferromagnetic α‐MnAs stripes increases. Thus, the aspect ratio p between the stripe width L and the stripe thickness t can be varied over a wide range. The magnetic properties of the finite‐size magnetic system are investigated as a function of the ratio p at room temperature. The transition from type‐I domains with meander‐like contrast in the magnetic force microscopy (MFM) image to type‐II domains with a line‐shaped contrast due to the division of the stripe into N subdomains across the stripe occurs at p ratios expected from a model based on the shape anisotropy. Besides the well‐known N = 3 type‐II domains also type‐II domains with N = 4, 5 were detected. When the stripe width approaches the period of the self‐organized structure, the boundary between two neighboring stripes is imaged as chessboard‐like contrast in the MFM pattern. The shape of the magnetic hysteresis loops changes with the p ratio or, in other words, with the predominance of in‐plane or out‐of plane magnetic moments in the demagnetized state. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MBE growth and interface formation of compound semiconductor heterostructures for optoelectronics
Authors: Tournié Eric , Trampert Achim
Published: June 2007

We give a bird's‐eye view of the interface formation during MBE growth of various quasi lattice‐matched as well as highly‐mismatched semiconductor heterostructures. We show that the parameters controlling the growth mode and the interface formation are numerous and that the optimum interface configuration depends on the materials system and on the target application. Our results obtained from various semiconductor materials systems demonstrate that this growth and interface‐related problem is much more complex than it has often been considered for many years. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure and stability of thorium carbonitrides
Authors: Shein I. R. , Shein K. I. , Medvedeva N. I. , Ivanovskii A. L.
Published: June 2007

The electronic structure of the monoclinic (α‐ThCN), hexagonal (β‐ThCN) and cubic (ThCx N1–x ) thorium carbonitrides is studied within the density‐functional theory (DFT). We predict the metal conductivity for the solid solutions ThCx N1–x , but both α‐ThCN and β‐ThCN phases should be semiconductors with band gap 1.49 eV and 1.97 eV, respectively. Distinct from the 5f metal carbides and nitrides, both Th6d and Th5f states give comparable contributions to the density of states at the Fermi level in ThCx N1–x . The enthalpies of formation were estimated relative to the different reagents and the largest values were obtained for the reactions with simple reagents (α‐Th, C, N). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Principles of robust design methodology
Authors: Arvidsson Martin , Gremyr Ida
Published: June 2007

The literature on robust design has focused chiefly on the development of methods for identifying robust design solutions. In this paper we present a literature review of conflicts and agreements on the principles of robust design. Through this review four central principles of robust design are identified: awareness of variation, insensitivity to noise factors, application of various methods, and application in all stages of a design process. These principles are comprised into the following definition of robust design methodology: Robust design methodology means systematic efforts to achieve insensitivity to noise factors. These efforts are founded on an awareness of variation and can be applied in all stages of product design. Copyright © 2007 John Wiley & Sons, Ltd.
Double sampling hotelling's T2 charts
Authors: Champ Charles W. , Aparisi Francisco
Published: June 2007

Two double sampling T2 charts are discussed. They only differ in how the second sample is used to suggest to the practitioner the state of the process. An optimal method using a genetic algorithm is given for designing these charts based on the average run length (ARL). An analytical method is used to determine run length performance of the chart. Comparisons are made with various other control charting procedures. Some recommendations are given. Copyright © 2007 John Wiley & Sons, Ltd.
Profiling the metabolic difference of seven tanshinones using high‐performance liquid chromatography/multi‐stage mass spectrometry with data‐dependent acquisition
Authors: Sun Jianghao , Yang Min , Han Jian , Wang Baorong , Ma Xiaochi , Xu Man , Liu Peng , Guo Dean
Published: June 2007

Tanshinones are a class of bioactive constituents in the roots of Salvia miltiorrhiza named Dan‐Shen in Chinese, which possess diverse pharmacological activities. In this study, we employed a sensitive high‐performance liquid chromatography/multi‐stage mass spectrometry (HPLC/MSn) method with data‐dependent acquisition and a dynamic exclusion program for the identification of phase I metabolites of seven tanshinones in rat bile after intravenous administration. These seven tanshinones are tanshinone IIA, sodium tanshinone IIA sulfonate (abbreviated as STS, a water‐soluble derivate of tanshinone IIA), cryptotanshinone, 15,16‐dihydrotanshinone I, tanshinone IIB, przewaquinone A and tanshinone I. Altogether 33 metabolites underwent monohydroxylation, dihydroxylation, dehydrogenation, D‐ring hydrolysis or oxidation reactions in the C‐4 or C‐15 side chain which were characterized by analyzing the LC/MSn data. Different metabolic reactions for tanshinones were dependent on the degree of saturation and the substituent group in the skeleton. Dehydrogenation was the major metabolic modification for cryptotanshinone with saturated A and D rings. 15,16‐Dihydrotanshinone I containing a saturated D ring was mainly metabolized through D‐ring hydrolysis. For tanshinone IIA, possessing a saturated A ring, hydroxylation was the major metabolic pathway. When there was hydroxyl group substitution in the C‐17 or C‐18 position, such as przewaquinone A and tanshinone IIB, or sulfonic group substitution in the C‐16 position, such as STS, higher metabolic stability than that of tanshinone IIA was shown and only trace metabolites were generated. Oxidation in the C‐4 or C‐15 side chain was a characteristic reaction for tanshinone IIA and hydroxylated tanshinone IIA. For tanshinone I, bearing unsaturated A and D rings simultaneously, no metabolites were detected. Copyright © 2007 John Wiley & Sons, Ltd.
(+)‐Silybin, a pharmacologically active constituent of Silybum marianum: fragmentation studies by atmospheric pressure chemical ionization quadrupole time‐of‐flight tandem mass spectrometry
Authors: Kéki Sándor , Tóth Katalin , Zsuga Miklós , Ferenczi Renáta , Antus Sándor
Published: June 2007

The fragmentation behavior of (+)‐silybin (1) and (+)‐deuterosilybin (2), as well as of their flavanone‐3‐ol‐type building blocks, such as 3,5,7‐trihydroxy‐2‐phenyl‐4‐chromanone (3) and 2‐(1,4‐benzodioxolanyl)‐3,5,7‐trihydroxy‐4‐chromanone (4), were investigated by atmospheric pressure chemical ionization quadropole time‐of‐flight tandem mass spectrometry in the positive ion mode (APCI(+)‐QqTOF MS/MS). The product ion spectra of the protonated molecules of 1 revealed a rather complicated fragmentation pattern with product ions originating from consecutive and competitive loss of small molecules such as H2O, CO, CH2O, CH3OH and 2‐methoxyphenol, along with the A+‐ and B+‐type ions arising from the cleavage of the C‐ring of the flavanone‐3‐ol moiety. The elucidation of the fragmentation behavior of 1 was facilitated by acquiring information on the fragmentation characteristics of the flavanone‐3‐ol moieties and 2. The capability of the accurate mass measurement on the quadrupole time‐of‐flight mass spectrometer allowed us to determine the elemental composition of each major product ion. Second‐generation product ion spectra obtained by combination of in‐source collision induced dissociation (CID) with selective CID (pseudo‐MS3) was also helpful in elaborating the fragmentation pathways and mechanism. Based on the experimental results, a fragmentation mechanism as well as fragmentation pathways for 1 and its flavanone‐3‐ol building blocks (3, 4) are proposed and discussed. Copyright © 2007 John Wiley & Sons, Ltd.
High‐performance liquid chromatography/electrospray ionization mass spectrometric characterization of new products formed by the reaction between flavanols and malvidin 3‐glucoside in the presence of acetaldehyde
Authors: Sun Baoshan , Santos Cláudia P. Reis , Leandro Maria C. , De Freitas Vítor , Spranger Maria I.
Published: June 2007

Monomer and polymer flavan‐3‐ols and anthocyanins are the two major groups of phenolic compounds in red wine and one of the most important reactions during red wine ageing is the condensation reaction, either direct or indirect, between these two classes of compounds. In this work, the reaction of (+)‐catechin, (−)‐epicatechin and dimer procyanidin B2 with malvidin 3‐glucoside, in the presence of acetaldehyde, was carried out in wine model solutions at pH 1.7 and 3.2. Identification of the reaction products was carried out by high‐performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI‐MS) and MSn analysis. Various reaction products were detected. The structures of three condensation products – malvidin‐3‐glucoside‐ethyl‐(epi)catechin‐1″‐hydroxyethyl, malvidin‐3‐glucoside‐ethyl‐dimer‐vinyl and malvidin‐3‐glucoside‐ethyl‐dimer‐1″‐hydroxyethyl – were identified in a model solution for the first time. Moreover, in the reaction solution containing dimer B2 at pH 3.2, monomer epicatechin, trimer and tetramer procyanidins were also detected indicating that, under these conditions, dimer procyanidins can either be hydrolyzed to monomers or polymerized to higher oligomer or polymers. Copyright © 2007 John Wiley & Sons, Ltd.
Arginine‐mimic labeling with guanidinoethanethiol to increase mass sensitivity of lysine‐terminated phosphopeptides by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Ahn Yeong Hee , Ji Eun Sun , Lee Ji Yeon , Cho Kun , Yoo Jong Shin
Published: June 2007

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) generally shows better mass sensitivity for arginine‐terminated peptides than for lysine‐terminated peptides, presumed to arise from the higher proton affinity of the guanidine group in arginine. Here, we report a new method for analyzing phosphopeptides in which phosphopeptides are labeled with a novel chemical tag, guanidinoethanethiol (GET), by a β‐elimination/Michael addition before MS analysis. GET labeling converts phosphoserine into guanidinoethylcysteine (Gec) containing a guanidine moiety, along with an increase in mass of 21.1 Da. GET‐labeled peptides are detected by MALDI MS with greatly increased peak intensities compared to those of intact phosphopeptides. In particular, GET labeling of lysine‐terminated phosphopeptides dramatically increased peak intensity. GET labeling of lysine‐terminated phosphopeptides improved sensitivity up to 22 times compared to that of the corresponding aminoethanethiol (AET) labeling, in which AET was used as a labeling tag containing an amino group instead of the guanidine group. These results show the guanidine group plays a very important role in increasing the observed sensitivity of MALDI MS for labeled peptide, derivatized from serine‐phosphorylated peptides. Copyright © 2007 John Wiley & Sons, Ltd.
Evaluating the added predictive ability of a new marker: From area under the ROC curve to reclassification and beyond
Authors: Pencina Michael J. , D' Agostino Ralph B. , D' Agostino Ralph B. , Vasan Ramachandran S.
Published: June 2007

Identification of key factors associated with the risk of developing cardiovascular disease and quantification of this risk using multivariable prediction algorithms are among the major advances made in preventive cardiology and cardiovascular epidemiology in the 20th century. The ongoing discovery of new risk markers by scientists presents opportunities and challenges for statisticians and clinicians to evaluate these biomarkers and to develop new risk formulations that incorporate them. One of the key questions is how best to assess and quantify the improvement in risk prediction offered by these new models. Demonstration of a statistically significant association of a new biomarker with cardiovascular risk is not enough. Some researchers have advanced that the improvement in the area under the receiver‐operating‐characteristic curve (AUC) should be the main criterion, whereas others argue that better measures of performance of prediction models are needed. In this paper, we address this question by introducing two new measures, one based on integrated sensitivity and specificity and the other on reclassification tables. These new measures offer incremental information over the AUC. We discuss the properties of these new measures and contrast them with the AUC. We also develop simple asymptotic tests of significance. We illustrate the use of these measures with an example from the Framingham Heart Study. We propose that scientists consider these types of measures in addition to the AUC when assessing the performance of newer biomarkers. Copyright © 2007 John Wiley & Sons, Ltd.
Let chaos reign, then rein in chaos—repeatedly: managing strategic dynamics for corporate longevity
Authors: Burgelman Robert A. , Grove Andrew S.
Published: June 2007

Combining longitudinal field research and executive experience, we propose that corporate longevity depends on matching cycles of autonomous and induced strategy processes to different forms of strategic dynamics, and that the role of alert strategic leadership is to appropriately balance the induced and autonomous processes throughout these cycles. We also propose that such strategic leadership is the means through which leadership style exerts its influence on corporate longevity. Our findings can be related to organizational research on structural inertia, learning and adaptation, as well as to formal theories of complex adaptive systems. They also contribute to resolving the seeming contradiction between a study of corporations that attributes exceptional long‐term success to leadership style, and the more common proposition that strategy is the determinant of long‐term performance. Copyright © 2007 John Wiley & Sons, Ltd.
Intended and unintended termination of international joint ventures
Authors: Makino Shige , Chan Christine M. , Isobe Takehiko , Beamish Paul W.
Published: June 2007

This study proposes that international joint ventures (IJVs) are terminated either when the initial purposes of the formation of the IJV have been achieved (intended termination), or when unanticipated contingencies that emerge in the external, internal, or inter‐partner conditions after the establishment of the IJV impede the continuation of its operation (unintended termination). Our study examines the factors that affect intended and unintended termination and the longevity of IJVs. The findings show that approximately 90 percent of all IJV terminations are unintended and 10 percent intended, and that the frequency of intended termination and unintended termination varies noticeably depending on the initial purposes of formation. This suggests that the termination of IJVs is significantly contingent on their formation. The findings also show that the longevity of IJVs varies according to the initial purposes of formation, the initial conditions under which the IJV is formed, and the types of unanticipated contingencies that it encounters. The key theoretical issues and practical implications of the distinction between the intended and unintended termination of IJVs are also discussed. Copyright © 2007 John Wiley & Sons, Ltd.