bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epigenetic control of plant stress response
Authors: Boyko Alex , Kovalchuk Igor 
Published: October 2007

AbstractLiving organisms have the clearly defined strategies of stress response. These strategies are predefined by a genetic make‐up of the organism and depend on a complex regulatory network of molecular interactions. Although in most cases, the plant response to stress based on the mechanisms of tolerance, resistance, and avoidance has clearly defined metabolic pathways, the ability to acclimate/adapt after a single generation exposure previously observed in several studies (Boyko A et al. [2007]: Nucleic Acids Res 35:1714–1725; Boyko and Kovalchuk, unpublished data), represents an interesting phenomenon that cannot be explained by Mendelian genetics. The latest findings in the field of epigenetics and the process of a reversible control over gene expression and inheritance lead to believe that organisms, especially plants, may have a flexible short‐term strategy of the response to stress. Indeed, the organisms that can modify gene expression reversibly have an advantage in evolutionary terms, since they can avoid unnecessary excessive rearrangements and population diversification. This review covers various epigenetic processes involved in plant stress response. We focus on the mechanisms of DNA methylation and histone modifications responsible for the protection of somatic cells and inheritance of stress memories. Environ. Mol. Mutagen., 2008. © 2007 Wiley‐Liss, Inc.
Slope–channel coupling between pipes, gullies and tributary channels in the Mocatán catchment badlands, Southeast Spain
Authors: Faulkner H. , Alexander R. , Zukowskyj P. 
Published: October 2007

AbstractThe dispersive nature of the highly sodic silts of the Triassic‐rich unit of the Góchar formation plays a fundamental role in the erosion of the Mocatán catchment badlands in Almería, where a rejuvenating pipe and incised channel network is rapidly evacuating slope materials. Referring to concepts of medium‐ and long‐term landscape evolution, and incorporating contemporary thoughts on the role of connectivity in system evolution from the geomorphological literature, this paper attempts to develop a conceptual model of the way geologic, topographic, material property and ecological factors combine to explain the complex geomorphological evolution of the site.An electronic distance measurement (EDM) survey was undertaken using a Leica TC3100, to produce a detailed topographic map. This database was supplemented by geomorphological, geological and ecological data derived from ground survey and remote sensing, and further morphometric analysis undertaken. Preferred orientations of channel segments, and the topographic distribution of pipe‐roof‐collapse features and outfalls in relation to known stratigraphic controls, suggests that, once coupled to the slope‐base channel, pipe networks develop in a systematic, sequential way. A wave of incision moving up the main channel reconnects channels with slopes, and the resulting increased hydraulic gradients on sideslopes encourage extensive deep pipe development for the first time in these materials. Once major pipe development is possible, three‐dimensional pipe networks enlarge and then collapse to form an extensive, partially coupled steep‐sided gully network. From this perspective, the coupling of the pipe to a rejuvenating channel is a significant intrinsic threshold event and the main reason that badlands have developed locally in these dispersive materials. It is concluded that erosion in this landscape will only be suppressed after a considerable period of slope‐base stability, which could allow a gradual loss of sodium from the surface by leaching or organic exchanges. Both theoretical and management implications are explored. Copyright © 2007 John Wiley & Sons, Ltd.
Probabilistic approach to voltage stability analysis with load uncertainty considered
Authors: Wu B. , Zhang Y. , Chen M. J. 
Published: October 2007

AbstractThis paper proposes a new probabilistic assessment algorithm of voltage stability based on Monte‐Carlo simulation and modal analysis considering uncertainty of the load level and load parameters. By Monte‐Carlo sampling, the bus load level is determined according to the forecasted bus load curve of a research period. The coefficients of the load polynomials, which include induction motors, are treated as random variables with normal distribution. A technique of normal distribution sampling is utilized to simulate these coefficients uncertainty. Voltage stability is evaluated in the form of indices such as the expected maximum loadability and the statistics of system participations, which are obtained from modal analysis near the point of collapse. A case study of the IEEE 118‐node system is given to demonstrate the validity of the proposed algorithm, and the effects of load uncertainty and the proportion of motors on probabilistic assessment of voltage stability are investigated. Copyright © 2007 John Wiley & Sons, Ltd.
New formulation and analysis of the system planning expansion model
Authors: Sadegheih A. 
Published: October 2007

AbstractIn this paper, an electrical power transmission network planning expansion is formulated for mixed‐integer programming, a genetic algorithm and tabu search (TS). Compared with other optimisation methods, GA's are suitable for traversing large search spaces since they can do this relatively rapidly and because the use of mutation diverts the method away from local minima, which will tend to become more common as the search space increases in size. GA's give an excellent trade‐off between solution quality and computing time and flexibility for taking into account specific constraints in real situations. TS has emerged as a new, highly efficient, search paradigm for finding quality solutions to combinatorial problems. It is characterised by gathering knowledge during the search, and subsequently profiting from this knowledge. The attractiveness of the technique comes from its ability to escape local optimality. The cost function of this problem consists of the capital investment cost in discrete form, the cost of transmission losses and the power generation costs. The DC load flow equations for the network are embedded in the constraints of the mathematical model to avoid sub‐optimal solutions that can arise if the enforcement of such constraints is done in an indirect way. The solution of the model gives the best line additions, and also provides information regarding the optimal generation at each generation point. This method of solution is demonstrated on the expansion of a 10 bus‐bar system to 18 bus‐bars. Finally, an empirical analysis of the effects of parameter values on genetic algorithm performance is tested. Copyright © 2007 John Wiley & Sons, Ltd.
Distortions in Electrochemical Impedance Spectroscopy Measurements Using 3‐Electrode Methods in SOFC. II. Effect of Electrode Activity and Relaxation Times
Authors: Cimenti M. , Birss V. I. , Hill J. M. 
Published: October 2007

AbstractThe 3‐electrode configuration is commonly applied to quantify the overpotential of anodes or cathodes in solid‐oxide fuel cells (SOFC). In this type of set‐up, a reference electrode (RE) is used to isolate the potential loss of one electrode from that of the entire cell; however, erroneous results can be obtained whenever the RE does not precisely separate the potential drop between the two active electrodes. In this study, we present the results of a theoretical and experimental analysis focused on verifying the effectiveness of the 3‐electrode configuration in electrochemical impedance spectroscopy measurements for the kinetic characterisation of SOFC electrode reactions. The focus of this paper is on the distortion of impedance measurements caused by differences in the area‐specific polarisation resistance and impedance time constants of the working and counter electrodes. The results obtained numerically and experimentally, both for planar and tubular SOFC cell geometries, prove the reliability of the theoretical model used. From the systematic simulation presented here and in our previous work, it was possible to formulate general guidelines for the design of 3‐electrode experimental SOFC. The theoretical model used here can also be used to verify the consistency of EIS measurements obtained with thin planar cells.
Investigation of the Ethanol Electro‐Oxidation in Alkaline Membrane Electrode Assembly by Differential Electrochemical Mass Spectrometry
Authors: Rao V. , Hariyanto  , Cremers C. , Stimming U. 
Published: October 2007

AbstractThe fuel cell differential electrochemical mass spectrometry (FC‐DEMS) measurements were performed for studying the ethanol oxidation reaction (EOR), using alkaline membrane electrode assemblies (MEAs) made up of nanoparticle Pt catalyst and alkaline polymeric membranes. The obtained results indicate that in an alkaline medium, ethanol undergoes significantly more complete electro‐oxidation to CO2 than in an acidic MEA using the same Pt anode. The CO2 current efficiency (CCE) can be compared for acidic and alkaline MEA with similar electrochemical active area on the anode side. The CCE estimated, in case of alkaline MEA with Pt anode, is around 55% at 0.8 V/RHE, 60 °C and 0.1 M ethanol. In comparison, under similar conditions, acidic MEAs using the same anode catalyst show only 2% CCE. This might indicate that the C–C bond scission rates are much higher in alkaline media. However, the mechanism of ethanol oxidation in alkaline media is not exactly known. CO2 produced in electrochemical reaction forms soluble carbonates in the presence of aqueous alkaline electrolyte. This makes it difficult to study ethanol oxidation in alkaline media using FTIR or model DEMS systems. The alkaline polymer electrolyte membranes as used in this study for making alkaline MEAs provide an important opportunity to observe CO2 produced during EOR using FC‐DEMS system.
Robust estimation and testing of haplotype effects in case‐control studies
Authors: Allen Andrew S. , Satten Glen A. 
Published: October 2007

AbstractHaplotype‐based analyses are thought to play a major role in the study of common complex diseases. This has led to the development of a variety of statistical methods for detecting disease‐haplotype associations from case‐control study data. However, haplotype phase is often uncertain when only genotype data is available. Methods that account for haplotype ambiguity by modeling the distribution of haplotypes can, if this distribution is misspecified, lead to substantial bias in parameter estimates even when complete genotype data is available. Here we study estimators that can be derived from score functions of appropriate likelihoods. We use the efficient score approach to estimation in the presence of nuisance parameters to a derive novel estimators that are robust to the haplotype distribution. We establish key relationships between estimators and study their empirical performance via simulation.Genet. Epidemiol. 2007. Published 2007 Wiley‐Liss, Inc.
Medication use in nursing home residents with advanced dementia
Authors: Blass David M. , Black Betty S. , Phillips Hilary , Finucane Thomas , Baker Alva , Loreck David , Rabins Peter V. 
Published: October 2007

AbstractObjectiveTo describe medication usage in nursing home residents with advanced dementia, to identify how this usage changed as patients advanced towards death, and to identify correlates of increased medication usage.MethodsProspective cohort study (CareAD) during which data on medication prescription were extracted from medical records at regular intervals using standardized extraction procedures.ResultsPatients (n = 125) were prescribed a mean of 14.6 medications during the 6 months prior to study enrollment. In a subgroup of patients who died during the study (n = 88), as the time of death approached, the total number of medications prescribed did not vary but the types of medications prescribed did change, with an increase in palliative medications such as opiate analgesics and a decrease in other medication classes such as antibiotics, anti‐dementia agents, cardiovascular agents, and psychotropic agents, among others. In linear regression analyses, total medication prescription at study entry was associated with study site, antibiotic treatment, presence of cardiovascular disease, and treatment of gastrointestinal or dermatological conditions.ConclusionsNursing home residents with advanced dementia are prescribed a large number of medications from numerous medication classes and prescribing patterns change over time. Further study is needed to determine the ideal approach to treating chronic medical problems at the end of life in this patient population. Copyright © 2007 John Wiley & Sons, Ltd.
One extra month of depression: the effects of caregiving on depression outcomes in the IMPACT trial
Authors: Thompson Alex , Fan Ming‐Yu , Unützer Jürgen , Katon Wayne 
Published: October 2007

AbstractBackgroundDepression occurs in 5–10% of older adults and there are nearly 6 million informal caregivers aged 65 or older. Prior research has focused on vulnerability to psychological distress in caregivers. Research has not addressed the caregiving burden of depressed elderly patients or how that burden affects depression treatment outcomes.AimsTo describe the self‐reported caregiving burden in a large, representative cohort of depressed elderly patients and compare depression treatment outcomes between caregivers and non‐caregivers.MethodsUnivariate and multiple regression analyses were performed comparing 24‐month depression outcomes (measured as depression free days) in those providing care at any time over the 24‐month trial to those who never reported a caregiving burden.ResultsAt 3, 6, 12, 18, and 24 months, nearly 10% of cohabitating elderly depressed patients provided care for basic activities such as bathing or dressing while nearly 20% reported providing care for other activities such as making phone calls or taking medication. Over 24 months, after adjusting for marital status, intervention status, and number of medical comorbidities, those reporting any caregiving burden had over 30 more days with depression compared to those with no caregiving burden. The IMPACT collaborative care model did not modify the effect of caregiving on depression outcomes.ConclusionCaregiving is common in depressed older adults and appears to affect response to depression treatment. In the future, interventions for depressed older adults should consider and specifically address caregiving activities in addition to specific depression treatment. Copyright © 2007 John Wiley & Sons, Ltd.
Price increase causes fewer sales of factory‐made cigarettes and higher sales of cheaper loose tobacco in Germany
Authors: Hanewinkel Reiner , Radden Christian , Rosenkranz Tobias 
Published: October 2007

AbstractAim of this study is the analysis of the price responsiveness of demand for cigarettes and loose tobacco in Germany over the period 1991–2006. In this period the average consumption of all kinds of cigarettes per capita (German population ≥ 15 years) declined from 634 pieces/quarter to 457pieces/quarter (−28%). Consumption of factory‐made cigarettes decreased from about 545 pieces/quarter to 330 pieces/quarter in 2006 (−39%). In the same time consumption of self‐made cigarettes increased from 89 pieces/quarter to 127 pieces/quarter (+42%). A one Euro Cent increase in price is associated with 28 cigarettes of all kinds consumed less per quarter. Data indicate that the different types of cigarettes are substitutes, e.g. there is evidence for a positive relationship between the price of factory‐made cigarettes and the consumption of hand‐made cigarettes. Thus, the increase in such consumption is rather driven by a positive cross‐price effect of 17.01. Data indicate additionally an overall decrease in the cigarette consumption and a partial switch to cheaper loose tobacco. The availability of low‐taxed loose tobacco may undermine the public health benefits of higher cigarette prices. Price differentials between tobacco products should be reduced in order to maximize the public health benefits of high cigarette prices. Copyright © 2007 John Wiley & Sons, Ltd.
Flavonoid Glycosides from Ranunculus chinensisBge.
Authors: Zou Yan‐Ping , Tan Chang‐Heng , Wang Bao‐De , Jiang Shan‐Hao , Zhu Da‐Yuan 
Published: October 2007

AbstractFour new flavonoid glycosides, 3‐O‐[α‐L‐arabinopyranosyl‐(1→2)‐β‐D‐galactopyranosyl]‐7‐O‐β‐D‐glucopyranosylkaempferol (1), 3‐O‐(α‐L‐arabinopyranosyl‐(1→2)‐{4‐O‐[(E)‐caffeoyl]‐β‐D‐galactopyranosyl})‐7‐O‐β‐D‐glucopyranosylquercetin (2), 3‐O‐{2‐O‐[(E)‐caffeoyl]‐α‐L‐arabinopyranosyl‐(1→2)‐β‐D‐galactopyranosyl}‐7‐O‐β‐D‐glucopyranosylkaemperfol (3), and 3‐O‐{2‐O‐[(E)‐caffeoyl]‐α‐L‐arabinopyranosyl‐(1→2)‐β‐D‐galactopyranosyl}kaempferol (4), together with two known compounds were isolated from the aerial parts of Ranunculus chinensis Bge. The structures of the new glycosides were determined on the basis of spectroscopic analysis, including 1D‐ and 2D‐NMR, and ESI‐MS techniques, and chemical methods.
Synthesis and Hybridization Properties of Oligodeoxynucleotides with Long‐Chain Linkers
Authors: Seio Kohji , Terada Takeshi , Mizuta Masahiro , Ohkubo Akihiro , Taguchi Haruhiko , Sekine Mitsuo 
Published: October 2007

AbstractNew oligonucleotides with a long‐chain linker (6,9‐dioxa‐3,12‐diazatetradecane‐1,14‐diyl) in their backbone were synthesized, and their hybridization properties were studied by measurement of their Tm curves and fluorescence spectra. The Tm analyses revealed that these oligonucleotides could bind to their complementary strands despite the presence of the long‐chain linker. We also demonstrated interesting fluorescence properties of oligodeoxynucleotides with an anthracen‐9‐ylmethyl group on one of the two N‐atoms in the long‐chain linker. The fluorescence intensity of these oligonucleotides increased upon their hybridization to the complementary strands and was sensitive to the presence of the mismatch base pairs at a specific position.
Folding–Unfolding Equilibrium of a Methylidene‐Substituted β‐Peptide
Authors: Schmid Nathan , Zagrovic Bojan , van Gunsteren Wilfred F. 
Published: October 2007

Abstractβ‐Peptides possess the ability to fold into secondary structure elements, and this property, together with resistance to biodegradation, makes these compounds interesting for pharmaceutical applications. Recently, a novel class of β‐peptides containing methylidene moieties was described. The GROMOS 53A6 force field was used to simulate the folding equilibrium of a β3‐hexapeptide with methylidene (CH2) groups at all six CA‐atoms. Due to the rotational barriers induced by these methylidene groups, the helical secondary‐structure elements, normally found in β3‐peptides, are disfavored in this molecule. Simulations, started from fully extended and 314‐helical conformations, showed that the molecule adopts a complete 28‐helix for ca. 5% of the time and partial 28‐helical conformations for ca. 20% of the time. Yet, as suggested by experiments, the folding equilibrium is dominated by unfolded conformations.
Tirucallane Triterpenoid Saponins from Munronia delavayiFranch
Authors: Cai Xiang‐Hai , Du Zhi‐Zhi , Luo Xiao‐Dong 
Published: October 2007

AbstractFour new tirucallane triterpenoid saponins, named munronosides I–IV (2–5), along with three known triterpenoids, sapelin B (1), melianodiol, and (3β)‐22,23‐epoxytirucall‐7‐ene‐3,24,25‐triol, were isolated from the EtOH extract of the whole plants of Munronia delavayi Franch by chromatographic methods. On the basis of spectroscopic evidences, the structures of 2–5 were elucidated as (20S,23R,24S)‐21,25‐epoxy‐29‐{{O‐β‐d‐glucopyranosyl‐(1→3)‐O‐[α‐l‐rhamnopyranosyl‐(1→6)]‐β‐d‐glucopyranosyl}oxy}‐23,24‐dihydroxytirucall‐7‐ene‐3,21‐dione (2), (3β,20S,23R,24S)‐21,25‐epoxy‐29‐{{O‐β‐d‐glucopyranosyl‐(1→3)‐O‐[α‐l‐rhamnopyranosyl‐(1→6)]‐β‐d‐glucopyranosyl}oxy}‐3,23,24‐trihydroxytirucall‐7‐en‐21‐one (3), (20S,23R,24S)‐24‐(acetyloxy)‐21,25‐epoxy‐29‐{{O‐β‐d‐glucopyranosyl‐(1→3)‐O‐[α‐l‐rhamnopyranosyl‐(1→6)]‐β‐d‐glucopyranosyl}oxy}‐23‐hydroxytirucall‐7‐ene‐3,21‐dione (4), and (3β,20S,23R,24S)‐24‐(acetyloxy)‐21,25‐epoxy‐29‐{{O‐β‐d‐glucopyranosyl‐(1→3)‐O‐[α‐l‐rhamnopyranosyl‐(1→6)]‐β‐d‐glucopyranosyl}oxy}‐3,23‐dihydroxytirucall‐7‐en‐21‐one (5).
CD133 negative glioma cells form tumors in nude rats and give rise to CD133 positive cells
Authors: Wang Jian , Sakariassen Per Ø. , Tsinkalovsky Oleg , Immervoll Heike , Bøe Stig Ove , Svendsen Agnete , Prestegarden Lars , Røsland Gro , Thorsen Frits , Stuhr Linda , Molven Anders , Bjerkvig Rolf , Enger Per Ø. 
Published: October 2007

AbstractCD133 is a cell surface marker expressed on progenitors of haematopoietic and endothelial cell lineages. Moreover, several studies have identified CD133 as a marker of brain tumor‐initiating cells. In this study, human glioblastoma multiforme biopsies were engrafted intracerebrally into nude rats. The resulting tumors were serially passaged in vivo, and monitored by magnetic resonance imaging. CD133 expression was analyzed at various passages. Tumors initiated directly from the biopsies expressed little or no CD133, and showed no contrast enhancement suggesting an intact blood‐brain barrier. During passaging, the tumors gradually displayed more contrast enhancement, increased angiogenesis and a shorter survival. Real‐time qPCR and immunoblots showed that this was accompanied by increased CD133 expression. Primary biopsy spheroids and xenograft tumors were subsequently dissociated and flow sorted into CD133 negative and CD133 positive cell populations. Both populations incorporated BrdU in cell culture, and expressed the neural precursor marker nestin. Notably, CD133 negative cells derived from 6 different patients were tumorgenic when implanted into the rat brains. For 3 of these patients, analysis showed that the resulting tumors contained CD133 positive cells. In conclusion, we show that CD133 negative glioma cells are tumorgenic in nude rats, and that CD133 positive cells can be obtained from these tumors. Upon passaging of the tumors in vivo, CD133 expression is upregulated, coinciding with the onset of angiogenesis and a shorter survival. Thus, our findings do not suggest that CD133 expression is required for brain tumor initiation, but that it may be involved during brain tumor progression. © 2007 Wiley‐Liss, Inc.