bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring the Chemistry of a Double‐Stranded Cycle with the Carbon Skeleton of the Belt Region of the C84 Fullerene
Authors: Stuparu Mihaiela , Lentz Dieter , Rüegger Heinz , Schlüter A. Dieter 
Published: October 2006

AbstractIntense scale‐up efforts greatly improved the availability of the known double‐stranded cycle 2 with two bridging ether units. The chemistry of 2 towards Bronsted and Lewis acids could, therefore, be investigated quite comprehensively. It was discovered that the reactivity of 2, whose carbon framework resembles the belt region of the C84 (D2) fullerene, is rather unusual as compared with acyclic model compounds. Whereas the latter could easily be dehydrated to the corresponding planar arenes, the former gave rise to a bouquet of unexpected reactions, which all avoided the aromatization of 2 to its still‐elusive, fully conjugated congener B. Intermediates generated from 2 under acidic conditions attack the solvent (e.g. toluene) to give 4, form bridging lactones to give 11 or close back to starting material 2 (e.g. from 16) rather than dehydrate to more highly conjugated structures on the way to the fully unsaturated target cycle B. The structure of compound 4 was solved by X‐ray diffraction. Through the reactions of 2 with Lewis acids, derivatives 14 and 15 became accessible. They are candidates for future attempts to achieve the desired aromatization under basic conditions or by thermal treatment. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Relevance of Ras gene mutations in the context of the molecular heterogeneity of multiple myeloma
Authors: Intini Daniela , Agnelli Luca , Ciceri Gabriella , Ronchetti Domenica , Fabris Sonia , Nobili Lucia , Lambertenghi‐Deliliers Giorgio , Lombardi Luigia , Neri Antonino 
Published: October 2006

AbstractRas gene mutations are a recurrent genetic lesion in multiple myeloma (MM). Here, we report a mutation analysis of N‐ and K‐Ras genes in purified plasma cell populations from a panel of 81 newly diagnosed MM patients stratified according to the most frequent genetic and molecular features associated with the neoplasia. Ras gene mutations, mostly involving the N‐Ras gene, were detected in 20% of the patients. Ras mutations did not correlate with the presence of chromosome 13q deletion, trisomy of chromosome 11, 1q amplification or hyperdiploidy. In addition, despite an appreciable association with tumours overexpressing Cyclin D1, Ras mutations did not correlate at significant levels with any of the proposed groups in the TC classification, based on the presence of the major IgH chromosomal translocations and expression of Cyclin D genes. Finally, transcription analyses revealed the presence of differentially expressed transcripts in human multiple myeloma cell lines carrying the Ras gene mutations but not in primary tumours. Overall, these data suggest that Ras gene mutations are not likely to represent a master lesion in MM but its relevance needs to be considered in the context of other genetic abnormalities. Copyright © 2006 John Wiley & Sons, Ltd.
The relationship between Indian monsoon precipitation along the Qinghai–Tibet Highway and differences in sensible heat flux
Authors: Wen L. , Yao T. , Li D. , Tian L. , Ma W. 
Published: October 2006

AbstractSensible heat flux greatly influences the Indian monsoon. In this study, we calculated sensible heat flux time‐series for 12 sites over the western Tibetan Plateau using Price and Dunne's formula and adjusting the stability function. The time‐series were derived from the field observations from the GEWEX Asian Monsoon Experiment (GAME)/Tibet programme under the Global Energy and Water Cycle Experiment (GEWEX). This paper demonstrates that monthly sensible heat fluxes show strong correlations with corresponding precipitation, and that the correlation coefficients increase with precipitation amount. The preceding winter and spring solid precipitation (snowfall and resulting snowpack) can also influence sensible heat flux in May, but the situation is complex. The correlations between heat flux and snowfall at Amdo, Naqu, and Lhasa are negative, but they are positive at Gaize (also known as Gerze) and Dingri. There is a significant relationship between how the variations from the mean calculated heat fluxes at Amdo differ from those at Rikaze, or Dingri, Cuona and Longzi, and their respective June–September precipitation amounts. This phenomenon may result from changes in circulation. When the sensible heat fluxes are above average north of the influence of the Indian monsoon and below average to the south, the summer monsoon circulation develops early and with greater intensity and precipitation, and vice versa. Copyright © 2006 John Wiley & Sons, Ltd.
Applying a real‐coded multi‐population genetic algorithm to multi‐reservoir operation
Authors: Chen L. , Chang F. J. 
Published: October 2006

AbstractThe primary objective of this study is to propose a real‐coded hypercubic distributed genetic algorithm (HDGA) for optimizing reservoir operation system. A conventional genetic algorithm (GA) is often trapped into local optimums during the optimization procedure. To prevent premature convergence and to obtain near‐global optimal solutions, the HDGA is designed to have various subpopulations that are processed using separate and parallel GAs. The hypercubic topology with a small diameter spreads good solutions rapidly throughout all of the subpopulations, and a migration mechanism, which exchanges chromosomes among the subpopulations, exchanges information during the joint optimization to maintain diversity and thus avoid a systematic premature convergence toward a single local optimum. Three genetic operators, i.e. linear ranking selection, blend‐α crossover and Gaussian mutation, are applied to search for the optimal reservoir releases. First, a benchmark problem, the four‐reservoir operation system, is considered to investigate the applicability and effectiveness of the proposed approach. The results show that the known global optimal solution can be effectively and stably achieved by the HDGA. The HDGA is then applied in the planning of a multi‐reservoir system in northern Taiwan, considering a water reservoir development scenario to the year 2021. The results searched by an HDGA minimize the water deficit of this reservoir system and provide much better performance than the conventional GA in terms of obtaining lower values of the objective function and avoiding local optimal solutions. Copyright © 2006 John Wiley & Sons, Ltd.
Towards dynamic catchment modelling: a Bayesian hierarchical mixtures of experts framework
Authors: Marshall Lucy , Nott David , Sharma Ashish 
Published: October 2006

AbstractDespite the abundance of existing hydrological models, there is no single model that has been identified as performing consistently over the range of possible catchment types and catchment conditions. An attractive alternative to selecting a single model is to combine the results from several different hydrological models, thereby providing a more appropriate representation of model uncertainty than is the case otherwise. Methods based on Bayesian statistical techniques provide an ideal means to compare and combine competing models, as they explicitly account for model uncertainty. Bayesian model averaging is one such alternative that combines individual models by weighting models proportional to their respective posterior probability of selection. However, the necessity of having fixed weights for each model over the entire length of the simulation period means that the relative usefulness of different models at different times is not considered.The hierarchical mixtures of experts (HME) framework is an appealing extension of the model averaging framework that allows the individual model weights to be estimated dynamically. Consequently, a model more capable at simulating low flow characteristics attains a higher weight (probability) when such conditions are likely, switching over to a lower weight when catchment storage increases. In this way, different models apply in different hydrological states, with the probability of selecting each model being allowed to depend on relevant antecedent condition characteristics. HME models provide additional flexibility compared with simple combinations of models, by allowing the way that model predictions are combined to depend on predictor variables. Thus, for hydrological models, the ‘switch’ from one model to another can depend on the existing catchment condition.This new modelling framework is applied using a simple conceptual model to 10 selected Australian catchments. The study regions are chosen to vary considerably in terms of size, yield and location. Results from this application are compared with the alternative where a single fixed model structure is applied. Comparison of the model simulations using the maximum log‐likelihood and the Nash‐Sutcliffe coefficient of efficiency show that more variance in streamflow was explained by the HME model, compared with the conceptual model alone for each of the catchments investigated. Copyright © 2006 John Wiley & Sons, Ltd.
Use of soil moisture data and curve number method for estimating runoff in the Loess Plateau of China
Authors: Huang Mingbin , Gallichand Jacques , Dong Cuiyun , Wang Zhanli , Shao Mingan 
Published: October 2006

AbstractThe Soil Conservation Service curve number (CN) method commonly uses three discrete levels of soil antecedent moisture condition (AMC), defined by the 5‐day antecedent rainfall depth, to describe soil moisture prior to a runoff event. However, this way may not adequately represent soil water conditions of fields and watersheds in the Loess Plateau of China. The objectives of this study were: (1) to determine the effective soil moisture depth to which the CN is most related; (2) to evaluate a discrete and a linear relationship between AMC and soil moisture; and (3) to develop an equation between CN and soil moisture to predict runoff better for the climatic and soil conditions of the Loess Plateau of China. The dataset consisted of 10 years of rainfall, runoff and soil moisture measurements from four experimental plots cropped with millet, pasture and potatoes. Results indicate that the standard CN method underestimated runoff depths for 85 of the 98 observed plot‐runoff events, with a model efficiency E of only 0·243. For our experimental conditions, the discrete and linear approaches improved runoff estimation, but still underestimated most runoff events, with E values of 0·428 and 0·445 respectively. Based on the measured CN values and soil moisture values in the top 15 cm of the soil, a non‐linear equation was developed that predicted runoff better with an E value of 0·779. This modified CN equation was the most appropriate for runoff prediction in the study area, but may need adjustments for local conditions in the Loess Plateau of China. Copyright © 2006 John Wiley & Sons, Ltd.
Subglacial drainage system changes of the Gulkana Glacier, Alaska: discharge and sediment load observations and modelling
Authors: Kido Daisaku , Chikita Kazuhisa A. , Hirayama Kenta 
Published: October 2006

AbstractHydrological characteristics of englacial and subglacial drainage systems in Gulkana Glacier, Alaska, were examined by analysing temporal variations of discharge and sediment load in the proglacial Phelan Creek in 2001. From data plots on semi‐log paper, it appeared appropriate to separate both discharge and sediment load into fast and slow components. The two components were possibly produced by two different drainage systems: an englacial and subglacial, ‘channellized’ system in the ablation zone, and a subglacial, ‘distributed’ system in the accumulation zone. The data indicate the occurrence of an event during which part of the ‘distributed’ drainage system changed into the ‘channellized’ drainage system. The daily time‐series of discharge and sediment load were represented using a tank model. In the model, the drainage from an additional tank was added, supposing that a subglacial reservoir full of water and sediment collapsed slowly when the subglacial drainage system changed from distributed to channellized. The simulation with the collapsed tank gave much more reasonable results than those with no collapsed tank. The contribution of the collapsed tank to total sediment load is 24%, which is much larger than 9% to total discharge. Copyright © 2006 John Wiley & Sons, Ltd.
An evaluation of the acute toxic properties of liquids derived from oil sands
Authors: Stubblefield W. A. , McKee R. H. , Kapp R. W. , Hinz J. P. 
Published: October 2006

AbstractThe acute toxicity of three materials derived from Athabasca Oil Sands—(1) bitumen plus naphtha, (2) untreated naphtha (0–250°C) and (3) synthetic crude oil (0–500°C)— was assessed in a battery of tests. In acute oral studies, all three test materials exhibited a low order of toxicity (LD50 > 5.0 g kg−1). The acute dermal LD50 was also low (> 3 g kg−1) for each test material. All three materials were judged to be ‘slight’ ocular irritants. Acute inhalation studies (6‐h exposures at the maximum attainable concentrations) produced varied responses. Bitumen plus naphtha administered at a concentration of 1.46 mg l−1 did not cause mortality in exposed rats or mice. Lung discoloration was the only necropsy finding of note. Untreated naphtha administered at a concentration of 10.6 mg l−1 was lethal to essentially all of the mice;but only two rats died. Necropsy findings included elevated weights in the liver and kidneys of the exposed mice, elevated lung weights in male rats and elevated liver weights in female rats. Synthetic crude oil administered at a concentration of (4 mg l−1) was lethal to 5/10 mice, but none of the rats (0/10) died. Severe hair loss was noted in the surviving mice, and slight alopecia was also observed in rats. Both species exhibited elevated liver weight, and elevated lung weight was noted in female rats.
Influence of trace metals on serum total sialic acids and perchloric acid—soluble proteins and sialic acids in mice
Authors: Patel A. B. , Venkatakrishna‐Bhatt H. 
Published: October 2006

AbstractMale Swiss mice were exposed to a single LD50 (75%; i.p.) of mercury, zinc, lead and manganese to determine their influence on serum sialic acid and protein levels after a refractory period of 48 h. They significantly elevated, in different proportions, the serum levels of total and perchloric acid (PCA)‐soluble sialic acids (biological marker) and PCA‐soluble proteins, thus indicating their toxicity.
Synthesis of the 5‐nitrofuran 2,4‐diacetylamino‐6‐(5‐nitro‐2‐furyl)‐1,3,5‐triazine‐6‐14C
Authors: Doose Dennis R. , Hoener Betty‐Ann 
Published: October 2006

AbstractThe synthesis of the 5‐nitrofuran 2,4‐diacetylamino‐6‐(5‐nitro‐2‐furyl)‐1,3,5‐triazine‐6‐14C is described. Furyllithium in ether is carboxylated with radio‐carbon dioxide generated from Ba14CO3. The furoic‐carbonyl‐14C acid is then esterified with diazoethane and nitrated with nitronium acetate. The resulting ethyl 5‐nitro‐2‐furoate‐carbonyl‐14C is then condensed with biguanide to give 2,4‐diamino‐6‐(5‐nitro‐2‐furyl)‐1,3,5‐triazine‐6‐14C. The final product is then obtained by refluxing the condensation product in acetic anhydride to give a yield of 18% based on the amount of Ba14CO3 at a specific activity of 43.2mCi/mmole.
Self‐radiolysis of tritium‐labelled fatty acid esters
Authors: Guarino A. , Pizzella R. , Possagno E. 
Published: October 2006

AbstractHigh specific activity methyl‐butyrate‐2, 3‐H3 and methyl‐stearate‐9, 10‐H3 were stored for approximately three months. The self‐radiolysis decomposition products were identified by means of radio‐gas chromatographic methods and the isotopic dilution technique. Rather high G‐values were found for the parent acids and for the destroyed ester molecules.
Deuterated organic compounds XXV synthesis of certain deuterated n‐undecanes and n‐dodecanes
Authors: Warner R. M. , Leitch L. C. 
Published: October 2006

AbstractThe synthesis of the following n‐undecanes and n‐dodecanes deuterated in specific positions is described: CH3(CH2)10CD3, CD3(CH2)10CD3, CH3(CD2)10CH3, [CD3(CD2)4)CH2]2, [CD3(CD2)4]2CH2, CD3(CD2)3(CH2)3 (CD2)3CD3, and CD3(CD2)3CH2 CD2CH2(CD2)3CD3. The following new intermediates were prepared in the course of these syntheses: CCl3CD2CD = CDCD2CN, CCl3CD2CD = CDCD2CO2H, CCl3CD2CD = CDCD2CO2C2H5, CCl3(CD2)4CO2C2H5, CH3(CD2)4CO2C2H5, CD3(CD2)4CO2C2H5, CH3(CD2)4CO2C2H5, CH3(CD2)4CD2OH, CH3(CD)4C2D2Br, CD3(CD2)4CO2D, [CD3(CD2)4]2CO, [CD3(CD2)4]2CHOH, [CD3(CD2)4]2CHBr, [CD3(CD2)3CH2]2CO, [CD3(CD2)3CH2]2CDOH, [CD3(CD2)3CH2]2CDBr, [CD3(CD2)3CH2]2CHOH, [CD3(CD2)3CH2]2CHBr.
Tritium labelling of amino‐acids and peptides by the Wilzbach method
Authors: Parmentier J. H. 
Published: October 2006

AbstractOptically pure L‐valine was labelled with tritium by the Wilzbach method. Only 4% of the activity of the radiochemically pure valine was found in D‐valine. This figure was determined by reverse isotope dilution.The suitability of this method for valine was tested, with good results, with DL‐valine also labelled by the Wilzbach method.
Synthesis of benzo [RST] pentaphene‐5, 15‐14C and of its oxidation products
Authors: Boger Eliahu , Bernfeld Peter 
Published: October 2006

Abstract14C labeled benzo [rst] pentaphene (V) known as 3, 4, 9, 10‐dibenzpyrene, 14C labeled benzo [rst] pentaphene‐5, 8‐diol, diacetate (VI) and 14C labeled benzo [rst] pentaphene‐5, 8‐dione (IV) have been synthesized for the study of the distribution, the metabolic fate and the mode of action of the carcinogenic hydrocarbon dibenzpyrene, which appears to differ from other known carcinogens with regard to these factors [1, 2].
Synthesis of 14C‐labelled isopropyl, diisopropyl and methyldiisopropyl amine
Authors: Colombini C. , Terbojevich M. , Peggion E. 
Published: October 2006

AbstractIsopropyl, diisopropyl and methyldiisopropyl amines, specifically labeled with 14C in the isopropyl moiety, have readily been prepared at a good yield, starting from Acetone‐2‐14C. Isopropylamine‐2‐14C [III] at 10 mC|mM was obtained by a two step synthesis with a 75% overall yield based on Acetone‐2‐14C. Diisopropylamine‐2‐14C [VI] at 3 mC|mM was prepared in a two step synthesis in 61% overall yield. From [VI], methyldiisopropylamine‐2‐14C [VII] at 1 mC|mM was obtained in one step at a 93% yield.Starting with various ketones, it is possible to carry out radiosynteses of homologous primary, secondary and tertiary amines according to the described reaction schemes.
Isotope exchange of active methyl hydrogens. III. Preparation of 2, 4, 6‐tri‐d3‐methylpyridine, 3, 5‐di‐d3‐methylphenol, 3, 5‐di‐d3‐methyl‐2‐acetylfuran, and 4, 6, 8‐tri‐d3‐methylazulene, from 2, 4, 6‐tri‐d3‐methylpyrylum perchlorate
Authors: Balaban A. T. , Gǎrd E. , Vasilescu A. , Barabas A. 
Published: October 2006

AbstractFrom 2, 4, 6‐tri‐d3‐methylpyrylium perchlorate the title compounds II‐V were obtained by reaction with aqueous or gaseous ammonia, aqueous sodium hydroxide, aqueous hydrogen peroxide and sodium cyclopentadienide, respectively. The preparation of II‐IV in aqueous solution proves that the nucleophilic additions to the pyrylium ring proceed faster than the dedeuteration. Infrared and nuclear magnetic resonance spectra of these compounds confirm that their methyl groups are deuterated.
A kinetic parameter concerning mass transfer in silica monolithic and particulate stationary phases measured by the peak‐parking and slow‐elution methods
Authors: Miyabe Kanji , Kobayashi Hiroshi , Tokuda Daisuke , Tanaka Nobuo 
Published: October 2006

AbstractMass transfer in monolithic C18‐silica stationary phases and C18‐silica gel particles was studied. A traditional kinetic parameter, γsDs, which is a diffusion coefficient of solute molecules in the stationary phase, was measured by two unusual approaches, i. e., peak‐parking and slow‐elution methods. The correlation between the ratio of γsDs to molecular diffusivity (Dm) and the retention factor (k) was represented by one common curve, irrespective of the RPLC conditions. A similar curved profile was also observed between another kinetic parameter (DLs), which is related to the axial diffusive molecular migration in the stationary phase, and the retention equilibrium constant (Ka). The values of DLs and Ka were calculated from those of γsDs and k, respectively. The ratio of DLs/Dm increases with decreasing Ka and seems to approach around unity when Ka is infinitely small. The dependence of DLs on Ka was also studied from extra‐thermodynamic points of view. The linear correlation between ln DLs and ln Ka suggests the existence of a kind of linear free energy relationship between the mass transfer in the stationary phase and the retention equilibrium. Because these characteristics of DLs are similar to those of the surface diffusion coefficient (Dsur), DLs seems to correspond to Dsur.
Visualization of astaxanthin localization in HT29 human colon adenocarcinoma cells by combined confocal resonance Raman and fluorescence microspectroscopy
Authors: Briviba Karlis , Bornemann Rainer , Lemmer Ulrich 
Published: October 2006

AbstractAstaxanthin, a carotenoid found in plants and seafood, exhibits antiproliferative, antioxidant and anticarcinogenic properties. We show that astaxanthin delivered with tetrahydrofuran is effectively taken up by cultured colon adenocarcinoma cells and is localized mostly in the cytoplasm as detected by confocal resonance Raman and broad‐band fluorescence microspectroscopy image analysis. Cells incubated with β‐carotene at the same concentration as astaxanthin (10 μM) showed about a 50‐fold lower cellular amount of β‐carotene, as detected by HPLC. No detectable Raman signal of β‐carotene was found in cells, but a weak broad‐band fluorescence signal of β‐carotene was observed. β‐Carotene, like astaxanthin, was localized mostly in the cytoplasm. The heterogeneity of astaxanthin and β‐carotene cellular distribution in cells of intestinal origin suggests that the possible defense against reactive molecules by carotenoids in these cells may also be heterogeneous.
Complete assignments 1H and 13C NMR spectral data of four anabaseine derivatives
Authors: Sobarzo‐Sánchez Eduardo , De la Fuente Julio , Quezada Elías , Castedo Luis 
Published: October 2006

AbstractThe anabaseine derivatives 6‐methoxy‐7‐hydroxy‐1‐(pyridin‐3‐yl)‐3,4‐dihydroisoquinoline, 6,7‐dimethoxy‐1‐(pyridin‐3‐yl)‐1,2,3,4‐tetrahydroisoquinoline and 6,7‐dimethoxy‐1‐(piperidin‐3‐yl)‐1,2,3,4‐tetrahydroisoquino‐ line were prepared either by demethylation with HBr or by reduction with different reagents, NaBH4 and H2/PtO2 from 6,7‐dimethoxy‐1‐(pyridin‐3‐yl)‐3,4‐dihydroisoquinoline, as starting material. The structures have been fully assigned by the combination of one‐ and two‐dimensional experiments. Copyright © 2006 John Wiley & Sons, Ltd.
Densin is a novel cell membrane protein of sertoli cells in the testis
Authors: Lassila Markus , Juhila Juuso , Heikkilä Eija , Holthöfer Harry 
Published: October 2006

AbstractCell–cell interactions between Sertoli cells and germ cells are crucial for the maturation of germ cells in spermatogenesis but the structural and functional aspects of the interactions remain to be fully elucidated. Densin is a junction protein suggested to play a role in establishment of specific cell–cell contacts in the post‐synaptic densities of the brain and the slit diaphragm of the kidney podocyte. In the present study, densin was discovered to be expressed in the testis of the man and the mouse. Expression of densin at the gene and the protein level was studied by using RT‐PCR and Western blotting analyses, and the localization of densin was explored with immunofluorescence staining. RT‐PCR and Western blotting analyses showed that densin is expressed at the gene and the protein levels. Immunofluorescence staining localized the expression of densin to the cell membranes of Sertoli cells suggesting that densin may be an adherens junction protein between Sertoli cells and developing germ cells. Densin is a novel testicular protein expressed in the cell membranes of Sertoli cells. Its functional role remains to be assessed. Mol. Reprod. Dev. 74: 641–645, 2007. © 2006 Wiley‐Liss, Inc.