bluuebunny/crossref_metadata_2025_split huggingface dataset:
TMZ‐induced PrPc/par‐4 interaction promotes the survival of human glioma cells
Authors: Zhuang Dongxiao , Liu Yingchao , Mao Ying , Gao Liang , Zhang Haishi , Luan Shihai , Huang Fengping , Li Qingquan 
Published: February 2011

AbstractMalignant gliomas recur even after extensive surgery and chemo‐radiotherapy. Although a relatively novel chemotherapeutic agent, temozolomide (TMZ), has demonstrated promising activity against gliomas, the effects last only a few months and drug resistance develops thereafter in many cases. It has been acknowledged that glioma cells respond to TMZ treatment by undergoing G2/M arrest, but not apoptosis. Here we demonstrate a phase‐specific chemotherapy resistance due to cellular prion protein (PrPc) in human glioma cells upon TMZ treatment. TMZ‐induced G2/M‐arrested cultures show an upregulation of PrPc expression and are more resistant, whereas G1/S‐phase cells that show decreased levels of PrPc are more sensitive to apoptosis. Furthermore, an investigation into the biological significance of PrPc association with par‐4 provided the first evidence of a relationship between the endogenous levels of PrPc and the resistance of glioma cells to the apoptotic effects of TMZ. Upon TMZ treatment, PrPc exerts its antiapoptotic activity by inhibiting PKA‐mediated par‐4 phosphorylation that are important for par‐4 activation, nuclear entry and initiation of apoptosis. In context with cell cycle‐dependent responses to chemotherapy, the data from this study suggest the possibility of exploiting the PrPc‐dependent pathway to improve the efficacy of TMZ‐based regimen for patients with gliomas.
Cross‐Linking Organic and Polyoxometalate Chemistries
Authors: Thorimbert Serge , Hasenknopf Bernold , Lacôte Emmanuel 
Published: February 2011

AbstractThis paper is a choral personal account on a longstanding and fruitful collaboration of organic and inorganic chemists to develop new hybrid polyoxometallic systems. .We explain our motivation and the context of our work that led to polyoxometalates with highly functional and reactive organic groups. Our approach yielded catalytically, biologically, and photochemically active systems.
Testing the ONIOM G2R3 model against donor–acceptor dissociation energies of group 13–15 complexes: Accuracy comparable to CCSD(T)/aug‐CC‐pVTZ at a fraction of the resource cost
Authors: Gilbert Thomas M. 
Published: February 2011

AbstractThe ability of the composite three‐layer ONIOM G2R3 (OG2R3) method to match experimental dissociation energies for group 13–15 donor–acceptor complexes was examined for a database of 34 complexes. The composite approach provides energies that agree reasonably with experiment, performing nearly as well as both the CCSD(T)/aug‐CC‐pVTZ and CCSD(T)/6‐311+G(2df, 2p) models for small molecules and nearly as well as the latter for slightly larger ones. Broadly, all three models exhibit average absolute errors of ∼3 kcal mol−1, and root mean square errors of ∼4 kcal mol−1. The average signed error suggest that the OG2R3 approach systematically underbinds by ∼2.3 kcal mol−1; if this is used as a general correction, the approach performs as well or better than the pure CCSD(T) models. However, the OG2R3 model can be applied to molecules too large to be studied by the other CCSD(T) methods, as it requires only a fraction of the time and computer resources. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Pharmacophore alignment search tool: Influence of the third dimension on text‐based similarity searching
Authors: Hähnke Volker , Klenner Alexander , Rippmann Friedrich , Schneider Gisbert 
Published: February 2011

AbstractPreviously (Hähnke et al., J Comput Chem 2010, 31, 2810) we introduced the concept of nonlinear dimensionality reduction for canonization of two‐dimensional layouts of molecular graphs as foundation for text‐based similarity searching using our Pharmacophore Alignment Search Tool (PhAST), a ligand‐based virtual screening method. Here we apply these methods to three‐dimensional molecular conformations and investigate the impact of these additional degrees of freedom on virtual screening performance and assess differences in ranking behavior. Best‐performing variants of PhAST are compared with 16 state‐of‐the‐art screening methods with respect to significance estimates for differences in screening performance. We show that PhAST sorts new chemotypes on early ranks without sacrificing overall screening performance. We succeeded in combining PhAST with other virtual screening techniques by rank‐based data fusion, significantly improving screening capabilities. We also present a parameterization of double dynamic programming for the problem of small molecule comparison, which allows for the calculation of structural similarity between compounds based on one‐dimensional representations, opening the door to a holistic approach to molecule comparison based on textual representations. © 2011 Wiley Periodicals, Inc. J Comput Chem , 2011.
Paths to which the nudged elastic band converges
Authors: Sheppard Daniel , Henkelman Graeme 
Published: February 2011

AbstractA recent letter to the editor (Quapp and Bofill, J Comput Chem 2010, 31, 2526) claims that the nudged elastic band (NEB) method can converge toward gradient extremal paths and not to steepest descent paths, as has been assumed. Here, we show that the NEB does in fact converge to steepest descent paths and that the observed tendency for the NEB to approach gradient extremal paths was a consequence of implementation errors. We also note that while the NEB finds steepest descent paths, these are not necessarily minimum energy paths in the sense of being a set of points which are minima in the potential energy surface perpendicular to the path. An example is given where segments of steepest descent paths follow potential energy ridges. © 2011 Wiley Periodicals, Inc. J Comput Chem , 2011.
Modeling the electron density kernels
Authors: Szarek Paweł , Komorowski Ludwik 
Published: February 2011

AbstractExisting approximation to the softness kernel, successfully explored in earlier work, has been extended; the normal Gauss distribution function has been used instead of the Dirac delta. The softness kernel becomes continuous functions in space and may be used to calculate the linear response function of the electron density. Three‐dimensional visualization of the softness kernel and the linear response function are presented for a nitrogen atom as a working example. By using a single parameter of the spatial Gauss distribution, the novel softness kernel has been adjusted to be consistent with the standard form of the hardness kernel, representing the leading fraction of the electronic interactions in the system. © 2011 by Wiley Periodicals, Inc.
Extraction properties of phthalic acid and aromatic polycarboxylic acids using various solvents
Authors: Zhou Zhiyong , Qin Wei 
Published: February 2011

AbstractBACKGROUND: To explore the extraction properties of aromatic acids produced in the oxidation of coal, the extraction equilibrium of phthalic acid (as a typical product) was studied using three solvents, 1‐octanol, 50% tributylphosphate (TBP)/kerosene, and 10% trialkylphosphine oxide (TRPO)/kerosene, and the feasibility of separating phthalic, [1,1′‐biphenyl]‐2,2′‐dicarboxylic and trimellitic acids is discussed.RESULTS: Phthalic acid extraction followed the sequence: 10% TRPO > 50% TBP > 1‐octanol, with recoveries from the TRPO and TBP systems being much larger than that for 1‐octanol. The stoichiometry of formation of the complexes of TBP and TRPO with phthalic acid was 1:1. The apparent extraction equilibrium constant for TRPO is much larger than that for TBP. The distribution coefficient of [1,1′‐biphenyl]‐2,2′‐dicarboxylic acid is much larger than that of the other two acids using 1‐octanol as the extractant and this acid could be removed by 1‐octanol from a mixture of the three acids. The extraction equilibrium correlations obtained for the individual acid component systems can be used to predict that of the acid mixture.CONCLUSION: The extent of phthalic acid extraction by the three solvents investigated is as follows: 10% TRPO > 50% TBP > 1‐octanol. The stoichiometry of the complex formation of TBP or TRPO and phthalic acid is 1:1, and the apparent extraction equilibrium constant for TRPO is much larger than that for TBP. 1‐octanol shows a good extractive selectivity for [1,1′‐biphenyl]‐2,2′‐dicarboxylic acid as compared with phthalic and trimellitic acids. Copyright © 2011 Society of Chemical Industry
Ethanol—the primary renewable liquid fuel
Authors: Datta Rathin , Maher Mark A. , Jones Coleman , Brinker Richard W. 
Published: February 2011

AbstractThis perspective paper establishes that ethanol has a long history of very good performance as a renewable liquid fuel blended with gasoline and can be used in over 80% of the automobile and other light duty transportation vehicles. It fits very well into the future of the combination of electricity and renewable liquid fuel for such transportation. It has also been established that renewable biomass feedstock is highly oxygenated and ethanol can be produced with high yields and efficiency with some conversion technologies—particularly the ‘Hybrid’ of gasification with bioconversion—that have been developed to the commercial implementation stage. Recent major studies conducted by the USDA, DOE and major National Laboratories have projected that large and sustainable biomass feedstock supplies are available and are going to be available to efficiently produce this ethanol in very large quantities of around 340 billion liters per year in the USA. The experience gained over the past 70 years in the south‐eastern USA has been summarized to further support the fact that efficient and sustainable biomass supply can be developed and maintained to support much increased usage. Copyright © 2011 Society of Chemical Industry
Stem cell antigen‐1 positive cell‐based systemic human growth hormone gene transfer strategy increases endosteal bone resorption and bone loss in mice
Authors: Hall Susan L. , Chen Shin‐Tai , Wergedal Jon E. , Gridley Daila S. , Mohan Subburaman , Lau K.‐H. William 
Published: February 2011

AbstractBackgroundThe present study assesses the effect of the stem cell antigen‐1 positive (Sca‐1+) cell‐based human growth hormone (hGH) ex vivo gene transfer strategy on endosteal bone mass in the mouse.MethodsSublethally irradiated recipient mice were transplanted with Sca‐1+ cells transduced with lentiviral vectors expressing hGH or β‐galactosidase control genes. Bone parameters were assessed by micro‐computed tomography and histomorphometry.ResultsThis hGH strategy drastically increased hGH mRNA levels in bone marrow cells and serum insulin‐like growth factor‐I (IGF‐I) (by nearly 50%, p < 0.002) in hGH recipient mice. Femoral trabecular bone volume of the hGH mice was significantly reduced by 35% (p < 0.002). The hGH mice also had decreased trabecular number (by 26%; p < 0.0001), increased trabecular separation (by 38%; p < 0.0002) and reduced trabecular connectivity density (by 64%; p < 0.001), as well as significantly more osteoclasts (2.5‐fold; p < 0.05) and greater osteoclastic surface per bone surface (2.6‐fold; p < 0.01).ConclusionsTargeted expression of hGH in cells of marrow cavity through the Sca‐1+ cell‐based gene transfer strategy increased circulating IGF‐I and decreased endosteal bone mass through an increase in resorption in recipient mice. These results indicate that high local levels of hGH or IGF‐I in the bone marrow microenvironment enhanced resorption, which is consistent with previous findings in transgenic mice with targeted bone IGF‐I expression showing that high local IGF‐I expression increased bone remodeling, favoring a net bone loss. Thus, GH and/or IGF‐I would not be an appropriate transgene for use in this Sca‐1+ cell‐based gene transfer strategy to promote endosteal bone formation. Published 2011 John Wiley & Sons, Ltd.
Characterisation of selected hazelnut cultivars: phenology, growing and yielding capacity, market quality and nutraceutical value
Authors: Solar Anita , Stampar Franci 
Published: February 2011

AbstractBACKGROUND: Sixteen hazelnut cultivars growing in the continental climate of Slovenia were analysed over 15 years for their phenology, growth habit, yield potential, susceptibility to hazelnut weevil and the pomological traits and phenolic content of their nuts in order to obtain a complex value of these cultivars for growers, the confectionary industry and consumers.RESULTS: Blooming occurred over an interval of 10–23 days for female (pistillate) flowers and 11–22 days for male (staminate) flowers. Nocchione, Romai, Pauetet, ID and Daria were the most productive cultivars, with a nine‐year cumulative yield ranging from 31.8 to 44.7 kg per plant. Pauetet, F. Coutard, Nocchione and Segorbe were less susceptible to unfavourable weather conditions during blooming and fertilisation, in terms of maintaining acceptable yields with limited blank production. Under integrated pest management, less than 2% of the nuts of Romai, Daria, TGDL and Nocchione were affected by hazelnut weevil, compared with an average of 5.5% for the other cultivars. Daria, Pauetet and T. Giffoni performed best with regard to kernel percentage and blanching ratio. The results suggest that raw kernels are a good source of the natural antioxidants gallic acid and epicatechin.CONCLUSION: The results of this study provide direction when choosing hazelnut cultivars for planting, consuming or processing. They can be applied not only in Slovenia and nearby countries but also in other parts of central and northern European countries with similar climates and growing conditions. Copyright © 2011 Society of Chemical Industry
Physical and stress–strain properties of wheat (Triticum aestivum) kernel
Authors: Babić Ljiljana , Babić Mirko , Turan Jan , Matić‐Kekić Snežana , Radojčin Milivoj , Mehandžić‐Stanišić Sanja , Pavkov Ivan , Zoranović Miodrag 
Published: February 2011

AbstractBACKGROUND: Two hard wheat varieties and one soft variety grown under the same agroecological conditions were analyzed for their physical and uniaxial stress–strain compression properties.RESULTS: The physical properties of wheat kernel were determined at a moisture content of 0.13 kg kg−1 (wet basis), whereas the stress–strain compression test was conducted at a kernel moisture content from 0.082 to 0.433 kg kg−1. Mean kernel lengths were 5.46 (5.37 and 5.38) mm, widths were 2.56 (2.47 and 2.62) mm and thicknesses were 2.12 (2.18 and 2.43) mm for Simonida, Dragana and NS 40S cultivars, respectively. Bulk densities were 791.34 (Simonida), 788.51 (Dragana) and 731.77 kg m−3 (NS 40S). The force at the yield point was 241.46 N for Dragana (moisture content 0.133 kg kg−1), 244.30 N for Simonida (0.136 kg kg−1) and 164.90 N for NS 40S (0.433 kg kg−1).CONCLUSION: The width and thickness of the analyzed kernels were small compared with the length, and bulk densities were also moderate. The yield point force values of the two hard varieties were 2.2 times higher than the values of the soft variety, at a moisture content of 0.136 kg kg−1 for Simonida, 0.133 kg kg−1 for Dragana and 0.141 kg kg−1 for NS 40S. Copyright © 2011 Society of Chemical Industry
Yield and fruit quality of four sweet corn hybrids (Zea mays) under conventional and integrated fertilization with vermicompost
Authors: Lazcano Cristina , Revilla Pedro , Malvar Rosa Ana , Domínguez Jorge 
Published: February 2011

AbstractBACKGROUND: Vermicompost has been proposed as a valuable fertilizer for sustainable agriculture. The effects of vermicompost on yield and quality of sweet corn were evaluated in this study. In two field trials, sweet corn plants were grown under (i) a conventional fertilization regime with inorganic fertilizer, and integrated fertilization regimes in which 75% of the nutrients were supplied by the inorganic fertilizer and 25% of the nutrients were supplied by either (ii) rabbit manure, or (iii) vermicompost. All three types of fertilization regime were supplied at two doses. Two pairs of nearly isogenic sweet corn hybrids homozygous for sugary1 and shrunken2 mutants were included in the trials to explore fertilizer × genotype interactions. Growth, yield and ear quality of the plants were evaluated in relation to the three fertilization regimes.RESULTS: In general, the integrated regimes yielded the same productivity levels as the conventional treatment. Moreover, both vermicompost and manure produced significant increases in plant growth and marketable yield, and also affected the chemical composition and quality of the marketable ear. Nevertheless, most of the observed effects of the organic fertilizers were genotype‐dependent.CONCLUSION: The results confirm that the use of organic fertilizers such as vermicompost has a positive effect on crop yield and quality. Nevertheless, these effects were not general, indicating the complexity of the organic amendment–plant interactions and the importance of controlling genetic variation when studying the effects of vermicompost on plant growth. Copyright © 2011 Society of Chemical Industry
Quantification of branched‐chain amino acids in blood spots and plasma by liquid chromatography tandem mass spectrometry for the diagnosis of maple syrup urine disease
Authors: Sowell John , Pollard Laura , Wood Tim 
Published: February 2011

AbstractIndividuals with maple syrup urine disease (MSUD) have an inherited metabolic disorder resulting in a deficiency in the branched‐chain keto‐acid dehydrogenase complex. As a result, these individuals have elevated concentrations of the branched‐chain amino acids valine, isoluecine, allo‐isoleucine, and leucine. MSUD presents in the first few days of life and progression may lead to irreversible intellectual disability, coma, cerebral edema, and death. However, early diagnosis and intervention can mitigate or eliminate many of the potential adverse effects. Consequently, it is important to develop techniques to screen for MSUD. We have developed an LC‐MS/MS assay for the diagnosis of MSUD. The method is amenable to high‐throughput formats due to the minimal sample prep required. The assay was shown to be robust, precise, and accurate. Finally, we identified and addressed some of the problems associated with working with bloodspots and implemented satisfactory approaches to overcoming these problems.
Ultrasonication extraction coupled with magnetic solid‐phase clean‐up for the determination of polycyclic aromatic hydrocarbons in soils by high‐performance liquid chromatography
Authors: Yang Fei , Long Yiming , Shen Rui , Chen Chunyan , Pan Di , Zhang Qianli , Cai Qingyun , Yao Shouzhuo 
Published: February 2011

AbstractC18‐functionalized magnetic microspheres synthesized in a three‐stage system and characterized by Fourier transform infrared (FTIR) spectroscopy and SEM were applied for clean‐up and enrichment of polycyclic aromatic hydrocarbons (PAHs) in soil samples combined with ultrasonication extraction. Magnetic solid‐phase extraction (MSPE) parameters, such as elution solvents, amounts of sorbents, enrichment time and organic modifier, were optimized together with ultrasonication time and extraction solvents. Under the optimal conditions, the developed method provided spiked recoveries of 63.2–92.8% with RSDs of less than 6.4% and limits of detection were 0.5–1.0 ng/g. This new method provides several advantages, such as high extraction efficiency, convenient extraction procedure and short analysis times. Finally, the method was successfully applied to the determination of polycyclic aromatic hydrocarbons in soil samples.
Chromatographic fingerprint analysis and simultaneous determination of eight lignans in Justicia procumbens and its compound preparation by HPLC‐DAD
Authors: Wang Linan , Pan Jianyu , Yang Meihua , Wu Jun , Yang Junshan 
Published: February 2011

AbstractHPLC fingerprints were developed for the quality evaluation of Justicia procumbens and its compound preparation, Jian‐er syrup, together with the simultaneous quantification of eight arylnaphthalide lignans (6′‐hydroxy justicidin B, 6′‐hydroxy justicidin A, 6′‐hydroxy justicidin C, justicidin B, chinensinaphthol methyl ether, justicidin C, taiwanin C, and neojusticin A). Samples were separated with a Shiseido Capcell Pak C18 reversed‐phase column (250×4.6 mm id, 5 μm) using acetonitrile and water as the mobile phase. The column temperature was maintained at 35°C and the wavelength of detector was set at 256 nm. For fingerprint analysis, 17 peaks were selected as the characteristic peaks for the evaluation of the similarities among different J. procumbens samples collected in different places. The structures of lignans were confirmed by diagnostic fragments in the positive ESI‐MSn. The new method was successfully applied for the chromatographic fingerprint analysis and simultaneous determination of eight lignans in its compound preparation, Jian‐er syrup. All the results indicated that HPLC fingerprint assay in combination with multi‐marker determination afforded a useful method for the quality control of J. procumbens and its compound preparation, Jian‐er syrup.
Separation behavior of U(VI) and Th(IV) on a cation exchange column using 2,6‐pyridine dicarboxylic acid as a complexing agent and its application for the rapid separation and determination of U and Th by ion chromatography
Authors: Jeyakumar Subbiah , Mishra Vivekchandra Guruprasad , Das Mrinal Kanti , Raut Vaibhavi Vishwajeet , Sawant Ramesh Mahadev , Ramakumar Karanam Lakshminarayana 
Published: February 2011

AbstractThe retention behavior of U and Th as their 2,6‐pyridine dicarboxylic acid (PDCA) complexes on a cation exchange column was investigated under low pH conditions. Based on the observed retention characteristics, an ion chromatographic method for the rapid separation of uranium and thorium in isocratic elution mode using 0.08 mM PDCA and 0.24 M KNO3 in 0.22 M HNO3 as the eluent was developed. Both uranium and thorium were eluted as their PDCA complexes within 2 min, whereas the transition and lanthanide metal cations were eluted as an unresolved broad peak after thorium. Under the optimized conditions both U and Th have no interference either from alkali and alkaline earth elements up to a concentration ratio of 1:500 or from other elements up to 1:100. The detection limits (LOD) of U and Th were calculated as 0.04 and 0.06 ppm, respectively (S/N=3). The precision in the measurement of peak area of 0.5 ppm of both U and Th was better than 5% and a linear calibration in the concentration range of 0.25–25 ppm of U and Th was obtained. The method was successfully applied to determine U and Th in effluent water samples.
Functionalization of Graphene Sheets by Polyacetylene: Convenient Synthesis and Enhanced Emission
Authors: Xu Xiujuan , Luo Qingying , Lv Wei , Dong Yongqiang , Lin Yi , Yang Quanhong , Shen Aiguo , Pang Daiwen , Hu Jiming , Qin Jingui , Li Zhen 
Published: February 2011

AbstractFor the first time, graphene materials have been conveniently covalently functionalized with polyacetylene through the nitrene chemistry reaction. The resultant functional polyacetylenes became soluble in different organic solvents and were well characterized, thus providing a new approach to prepare graphene‐polymer composite materials.
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