bluuebunny/crossref_metadata_2025_split huggingface dataset:
Marine benthic macrophytes as possible nitrogen source in agriculture
Authors: Karyotis Theodore , Orfanidis Sotiris , Reizopoulou Sofia 
Published: August 2006

AbstractMarine benthic macrophytes were examined as possible nitrogen (N) sources for agriculture in Greece in terms of N mineralization and available standing stocks. Net N mineralization patterns were determined over a 30‐week incubation period under aerobic conditions. Ulva sp., Cystoseira barbata C. Agardh, and Posidonia oceanica (L.) Delile storm‐cast material (SC) and harvested leaves (L) were incorporated into acidic, slightly acidic after liming, and alkaline soils and incubated at 35°C. From the initial stage until the 12th week of incubation, ammonification was higher than nitrification in most cases. The decreasing order of mineralized N originating from macrophytes was: Ulva sp. > P. oceanica (SC) > C. barbata > P. oceanica (L). Rates of net N mineralization of the macrophytes were the highest in the alkaline soil, whereas the lowest values were recorded in the strongly acidic soil. Application of Ca into the acidic soil revealed a considerable increase of N mineralization. Immobilization and ammonification were observed after incorporation of Ulva sp. into the acidic soil. As Ulva sp. proved to be the only potential alternative N source for arable crops, its standing stocks in two geographically different Greek lagoons, the Vassova Lagoon (N Greece) and Papas Lagoon (S Greece) were estimated. It was estimated that 2 ha of Ulva could supply adequate N to cultivate approximately 1 ha cotton. Posidonia and Cystoseira did not show potential as an alternative N source for agriculture and especially in plant nutrition.
Pedo‐ecological consequences of lithological discontinuities in soils—examples from Central Europe
Authors: Lorz Carsten , Phillips Jonathan D. 
Published: August 2006

AbstractSoil profiles having lithological discontinuities, i.e., stratified or layered profiles, occur worldwide. Their genesis as part of the upper‐regolith formation is comparatively well understood, particularly in Central Europe where extensive research on relic periglacial cover beds has been done. But the pedogenetic and ecological implications of lithologically discontinuous soils (LDS) are less well known. Most textbooks rely on the so‐called A‐B‐C‐model as a climate‐driven approach to soil formation.After reviewing definitions and concepts of lithological discontinuities and how they form, we present a pedogenetic model extending the traditional approach by considering substrate genesis and regolith dynamics. The consequences in the interpretation of vertical distributions of parameters of soil acidification and of heavy metals are investigated for typical soil profiles from the W Ore Mountains and the central‐German lowlands. Results show how lithological discontinuities influence the depth gradients and that properties inherited from substrate should be distinguished, if possible, from those developed by pedogenesis.
Permanent–soil monitoring sites for documentation of soil‐fertility development after changing from conventional to organic farming
Authors: Quintern Michael , Joergensen Rainer Georg , Wildhagen Holger 
Published: August 2006

AbstractFor monitoring soil fertility after changing farm management from highly conventional to organic farming on the newly established research farm of Kassel University, two permanent–soil monitoring sites were installed in 1999. Representative locations for installing the permanent–soil monitoring sites were selected using geographical information systems (GIS), based on available data from geology, topography, soil taxation, land use, and intensive auger‐borehole records and analysis with a very high spatial resolution of data. The soils are represented by a Luvisol derived from loess and a Vertisol developed from claystone. The soil properties of the two monitoring sites measured immediately after changing to organic farming showed high contents of extractable nutrients as a result of the former intensive fertilization practice during conventional farm management. The microbial soil properties of the two monitoring sites were in the medium range of regional soils. A first evaluation of the development of soil properties was done after 5 y of monitoring. The soil organic‐matter content increased slightly after grass‐clover and after application of farmyard manure. The amounts of K and P decreased clearly at the loess site without application of farmyard manure. At the clay site, the unique application of farmyard manure led to increasing contents of extractable K and P in the top soil. The variation of soil properties increased clearly after perennial crops like grass‐clover and in years after application of farmyard manure.
Automatic characterization of ignition processes with machine learning clustering techniques
Authors: Blurock Edward S. 
Published: August 2006

AbstractMachine learning clustering techniques are used to characterize and, after the training phase, to identify phases within an ignition process. For the ethanol mechanism used in this paper, four physically identifiable phases were found and characterized: the initiation phase, preignition phase, ignition phase, and the postignition phase. The clustering is done with respect to fuzzy logic predicates identifying the maxima, minima, and inflection points of the species profiles. The cluster descriptions characterize the phases found and are in human interpretable form. In addition, these descriptions are powerful enough to be used to predict the phase structure under new conditions. Cluster phases were calculated for the ethanol mechanism at an equivalence ratio of 0.5, a pressure of 3.3 bar, and the temperatures 1200, 1300, 1400, and 1500 K. The resulting cluster phase descriptions were then successfully used to predict the phase structure and ignition delay times for other temperatures in the range from 1200 to 1500 K. The effect of different fuzzy logic predicate profile descriptions is studied to emphasize that the boundaries of some phases, specifically that between the preignition and the ignition phase, are a matter of what the modeler considers important. The end of the ignition phase corresponds to the ignition delay time and was relatively independent of the predicate descriptions used to determine the phases. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 621–633, 2006
Kinetics of the esterification of acetic acid with 2‐propanol: Impact of different acidic cation exchange resins on reaction mechanism
Authors: Ali Sami H. , Merchant Sabiha Q. 
Published: August 2006

AbstractThe kinetics of the esterification of acetic acid with the secondary alcohol, 2‐propanol, catalyzed by the cation exchange resins, Dowex 50Wx8‐400, Amberlite IR‐120, and Amberlyst 15 has been studied at temperatures of 303, 323, and 343 K; acid to alcohol molar ratios of 0.5, 1, and 2; and catalyst loadings of 20, 40, and 60 g/L. The equilibrium constant was experimentally determined, and the reaction was found to be mildly exothermic. External and internal diffusion limitations were absent under the implemented experimental conditions. Systems catalyzed by gel‐type resins (Dowex 50Wx8‐400 and Amberlite IR‐120) exhibit some similarities in their reaction kinetics. Increase in reaction temperature, acid to alcohol ratio, and catalyst loading is found to enhance reaction kinetics for the three catalysts. The pseudohomogeneous (PH), Eley Rideal (ER), Langmuir Hinshelwood (LH), modified Langmuir Hinshelwood (ML), and Pöpken (PP) models were found to predict reaction kinetics with mean relative errors of less than 5.4%. However, the ML model was found to be better for predicting reaction kinetics in the systems catalyzed by gel‐type resins, while the PP model was better for the system catalyzed by the macroreticular catalyst, Amberlyst 15. The Eact for the forward reaction is found to be 57.0, 59.0, and 64.0 kJ/mole for the systems catalyzed by Dowex 50Wx8‐400, Amberlite IR‐120, and Amberlyst 15, respectively. For these three catalysts, the adsorption equilibrium constants of the components present in the system increase in the same order as do the solubility parameters of the component. Nonideality in the system is successfully accounted for by the UNIFAC model. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 593–612, 2006
Effects of NO2, CO, O2, and SO2 on oxidation kinetics of NO over Pt‐WO3/TiO2 catalyst for fast selective catalytic reduction process
Authors: Irfan Muhammad Faisal , Goo Jeong Hoi , Kim Sang Done 
Published: August 2006

AbstractThe selective catalytic reduction rate of NO with N‐containing reducing agents can be enhanced considerably by converting a part of NO into NO2. The enhanced reaction rate is more pronounced at lower temperatures by using an equimolar mixture of NO and NO2. The kinetics of NO oxidation over Pt‐WO3/TiO2 catalyst has been determined in a fixed‐bed reactor with different concentrations of oxygen, nitric oxide, and nitrogen dioxide in the presence of 8% water. It has been found that the reaction is second order with respect to nitric oxide, first order for oxygen with a third‐order rate constant. Also, it is found that there is no effect on the reaction order with an addition of NO2, CO, or SO2. It follows the same second order but the reaction rate is found to be changed. It is observed that in the case of NO2 and SO2, the reaction rate tends to decrease, but it increases with the addition of CO into the feed. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 613–620, 2006
Kinetics and mechanism of interaction of dipeptide (glycyl–glycine) with ninhydrin in aqueous micellar media
Authors: Akram Mohd. , Zaidi Neelam Hazoor , Kabir‐ud‐Din  
Published: August 2006

AbstractThe rates of reaction between ninhydrin and dipeptide glycyl–glycine (Gly–Gly) have been determined by studying the reaction spectrophotometrically at 70°C and pH 5.0 in aqueous and in aqueous cationic micelles of cetyltrimethylammonium bromide (CTAB). The reaction follows first‐ and fractional‐order kinetics, respectively, in [Gly–Gly] and [ninhydrin]. The observed rate constant is affected by [CTAB] changes and the maximum rate enhancement is ca. three‐fold. As the kψ − [CTAB] profile shape is characteristic of bimolecular reactions catalyzed by micelles, the catalysis is explained in terms of the pseudo‐phase model of the micelles (proposed by Menger and Portnoy and developed by Bunton and Romsted). The presence of inorganic salts (NaCl, NaBr, Na2SO4) does not reveal any regular effect but the data with organic salts (NaBenz, NaSal) show an increase in the rate followed by a decrease. The kinetic data have been used to calculate the micellar binding constants KS for Gly–Gly and KN for ninhydrin and the respective values are 317 and 69 mol−1 dm3. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 643–650, 2006
Micelle‐catalyzed reaction of ninhydrin withDL‐valine in the absence and presence of organic solvents
Authors: Kabir‐ud‐Din  , Fatma Waseefa , Khan Zaheer 
Published: August 2006

AbstractKinetics of theDL‐valine‐ninhydrin reaction has been studied spectrophotometrically under varying conditions of [CTAB], [ninhydrin], [DL‐valine], pH, temperature, and %(v/v) organic solvents (solvents used: 1‐propanol, methylcellosolve, acetonitrile, and dimethyl sulfoxide). Addition of CTAB and increase in the proportion of organic solvents, both showed catalyzing effect on the reaction. The effect of simultaneous presence of CTAB and DMSO in the reaction mixture has also been seen. The rate profiles obtained for solutions containing from 10% to 70% DMSO exhibited clear maxima that shifted progressively to higher concentrations of CTAB. The experimental results are explained in terms of specific solvent effects and the formation of stoichiometric hydrate DMSO · 2H2O and the inhibitory effect of DMSO on micelle formation. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 634–642, 2006
Mass spectrometry‐based metabolomics
Authors: Dettmer Katja , Aronov Pavel A. , Hammock Bruce D. 
Published: August 2006

AbstractThis review presents an overview of the dynamically developing field of mass spectrometry‐based metabolomics. Metabolomics aims at the comprehensive and quantitative analysis of wide arrays of metabolites in biological samples. These numerous analytes have very diverse physico‐chemical properties and occur at different abundance levels. Consequently, comprehensive metabolomics investigations are primarily a challenge for analytical chemistry and specifically mass spectrometry has vast potential as a tool for this type of investigation. Metabolomics require special approaches for sample preparation, separation, and mass spectrometric analysis. Current examples of those approaches are described in this review. It primarily focuses on metabolic fingerprinting, a technique that analyzes all detectable analytes in a given sample with subsequent classification of samples and identification of differentially expressed metabolites, which define the sample classes. To perform this complex task, data analysis tools, metabolite libraries, and databases are required. Therefore, recent advances in metabolomics bioinformatics are also discussed. © 2006 Wiley Periodicals, Inc., Mass Spec Rev 26:51–78, 2007
Prostate cancer stem/progenitor cells: Identification, characterization, and implications
Authors: Tang Dean G. , Patrawala Lubna , Calhoun Tammy , Bhatia Bobby , Choy Grace , Schneider‐Broussard Robin , Jeter Collene 
Published: August 2006

AbstractSeveral solid tumors have now been shown to contain stem cell‐like cells called cancer stem cells (CSC). These cells, although generally rare, appear to be highly tumorigenic and may be the cells that drive tumor formation, maintain tumor homeostasis, and mediate tumor metastasis. In this Perspective, we first provide our insight on how a CSC should be defined. We then summarize our current knowledge of stem/progenitor cells in the normal human prostate (NHP), an organ highly susceptible to hyperproliferative diseases such as benign prostate hyperplasia (BPH) and prostate cancer (PCa). We further review the evidence that cultured PCa cells, xenograft prostate tumors, and patient tumors may contain stem/progenitor cells. Along with our discussion, we present several methodologies that can be potentially used to identify putative tumor‐reinitiating CSC. Finally, we present a hypothetical model for the hierarchical organization of human PCa cells and discuss the implications of this model in helping understand prostate carcinogenesis and design novel diagnostic, prognostic, and therapeutic approaches. © 2006 Wiley‐Liss, Inc.
Overexpression of TGF‐β1 in esophageal (Barrett's) adenocarcinoma is associated with advanced stage of disease and poor prognosis
Authors: von Rahden Burkhard H. A. , Stein Hubert J. , Feith Marcus , Pühringer Franziska , Theisen Jörg , Siewert J. Rüdiger , Sarbia Mario 
Published: August 2006

AbstractExpression of TGF‐β1, a major member of the TGF‐β superfamily and important promoter of tumor growth, was investigated in a series of primary resected esophageal (Barrett's) adenocarcinomas to establish its potential clinical significance and prognostic relevance in this entity. A series of 123 primary resected adenocarcinomas of the distal esophagus, arising in association with Barrett's esophagus, and corresponding normal squamous epithelium (n = 12) and non‐malignant Barrett's mucosa (n = 11), were investigated by means of quantitative RT‐PCR for expression of TGF‐β1, using paraffin embedded tissue samples. Gene expression levels were correlated with clinical parameters and overall survival. TGF‐β1 mRNA was expressed in all tumors, but relative gene expression levels varied largely among different tumors. The relative gene expression was significantly higher in tumor tissue compared to squamous epithelium (P = 0.005) and Barrett's mucosa (P=0.002), expressing only low amounts of TGF‐β1. Relative overexpression of the TGF‐β1 gene was associated with advanced UICC stage (III/IV vs. I/II; P = 0.009), depth of tumor infiltration (pT3 vs. pT1/2; P < 0.001), nodal involvement (pN1 vs. pN0; P = 0.006), and lymphatic vessel invasion (L1 vs. L0; P = 0.011). On univariate survival analysis, TGF‐β1 overexpression had a significant negative impact on survival (log rank test; P = 0.0255). However, the prognostic impact was not independent from other strong predictors of survival (pT, pN) on multivariate survival analysis. Our data show that TGF‐β1 overexpression is associated with advanced stage of esophageal adenocarcinoma and implies a negative impact on survival. The TGF‐β pathway may be a potential target for molecular therapies of advanced tumors of this entity. © 2006 Wiley‐Liss, Inc.
Benzo[a]pyrene diol‐epoxide (B[a]PDE) upregulates COX‐2 expression through MAPKs/AP‐1 and IKKβ/NF‐κB in mouse epidermal Cl41 cells
Authors: Ouyang Weiming , Ma Qian , Li Jingxia , Zhang Dongyun , Ding Jin , Huang Yi , Xing Mingzhao , Huang Chuanshu 
Published: August 2006

AbstractBenzo[α]pyrene‐7,8‐diol‐9,10‐epoxide (B[a]PDE), the major metabolite of benzo[a]pyrene (B[a]P), shows an ultimate complete carcinogen in various animals and is a causative agent for human cancers. However, its effects on the activation of signal pathways and the expression of genes involved in its carcinogenic effect remain largely unknown. In this study, the effects of B[a]PDE on induction of cyclooxygenase (COX)‐2 and the signal pathways leading to the induction were investigated. Treatment of mouse epidermal Cl41 cells with B[a]PDE caused an increase in the expression of COX‐2 at both transcription and protein levels, while its parental compound B[a]P did not show significant inductive effect. The COX‐2 induction by B[a]PDE was dependent on the activation of mitogen‐activated protein kinases (MAPK)s/activation protein (AP)‐1 pathway, because inhibition of AP‐1 by either overexpression of TAM67 (dominant negative mutant of c‐jun), or pretreatment of cells with PD98059 (MEK1/2‐ERKs pathway inhibitor) or SB202190 (p38K inhibitor), markedly inhibited B[a]PDE‐induced COX‐2 expression. In addition, impairment of NF‐κB pathway by either NEMO‐BDBP (an NF‐κB specific inhibitor) or IκB kinase (IKK)β‐KM (dominant negative mutant of IKKβ) also caused marked reduction of COX‐2 induction by B[a]PDE. In contrast, inhibition of nuclear factor of activated T cells (NFAT) with FK506, did not show any effect on B[a]PDE‐induced COX‐2 expression. Collectively, these data indicate that exposure of Cl41 cells to B[a]PDE can induce COX‐2 expression by increasing its transcription, which requires the activation of MAPKs/AP‐1 and IKKβ/NF‐κB pathways, but not NFAT pathway. In view of the importance of COX‐2 in carcinogenesis, we anticipate that the induction of COX‐2 by B[a]PDE may coordinate its mutagenic effects to facilitate the development of skin cancer. © 2006 Wiley‐Liss, Inc.
Force steadiness, muscle activity, and maximal muscle strength in subjects with subacromial impingement syndrome
Authors: Bandholm Thomas , Rasmussen Lars , Aagaard Per , Jensen Bente Rona , Diederichsen Louise 
Published: August 2006

AbstractWe investigated the effects of the subacromial impingement syndrome (SIS) on shoulder sensory‐motor control and maximal shoulder muscle strength. It was hypothesized that both would be impaired due to chronic shoulder pain associated with the syndrome. Nine subjects with unilateral SIS who remained physically active in spite of shoulder pain and nine healthy matched controls were examined to determine isometric and isokinetic submaximal shoulder‐abduction force steadiness at target forces corresponding to 20%, 27.5%, and 35% of the maximal shoulder abductor torque, and maximal shoulder muscle strength (MVC). Electromyographic (EMG) activity was assessed using surface and intramuscular recordings from eight shoulder muscles. Force steadiness was impaired in SIS subjects during concentric contractions at the highest target force level only, with muscle activity largely unaffected. No between‐group differences in shoulder MVC were observed. The present data suggest that shoulder sensory‐motor control is only mildly impaired in subjects with SIS who are able to continue with upper body physical activity in spite of shoulder pain. Thus, physical activity should be continued by patients with SIS, if possible, to avoid the loss in neural and muscle functions associated with inactivity. Muscle Nerve, 2006
Negative impact of urinary incontinence on quality of life, a cross‐sectional study among women aged 49–61 years enrolled in the GAZEL cohort
Authors: Saadoun Karim , Ringa Virginie , Fritel Xavier , Varnoux Noëlle , Zins Marie , Bréart Gérard 
Published: August 2006

AbstractAimsThe aim of the study was to analyze the relations between severity of urinary incontinence (UI), defined as involuntary loss of urine considered to be a hygienic or social problem, and quality of life (QoL) among middle‐aged French working women enrolled in a cohort study, while taking into account characteristics that may affect this relation.MethodsData came from self‐administered mail questionnaires completed by 2,640 women aged 49–61 years in the GAZEL cohort of utility company employees. The analysis considered social and demographic characteristics, lifestyle, hormone status, and body mass index. We used bivariate and multivariate analysis to study the associations between UI severity (measured by SANDVIK's index) and QoL scales (Contilife, specific for UI, and the generic Nottingham Health Profile).ResultsThe sample included 556 women (21%) with UI. QoL alterations associated with UI severity were observed for all six Contilife dimensions (daily and effort activities, self‐image, emotional impact, sexuality, and well‐being) and two dimensions of the NHP (pain and physical mobility). These results remain after adjustment for age, BMI, and living arrangements.ConclusionsUI affects QoL even among women from a nonclinical population, and the more severe the UI, the more harmful the effect. These results raise the question of whether UI in its severe forms should be considered a disability because of its negative effects on mobility in daily life. Neurourol. Urodynam. 25:696–702, 2006. © 2006 Wiley‐Liss, Inc.
Having a child to save a sibling: Reassessing risks and benefits of creating stem cell donors
Authors: Morgan Elaine R. , Girod Jennifer , Rinehart John S. 
Published: August 2006

AbstractThis manuscript assesses the risks, benefits, and ethical concerns regarding the use of assisted reproductive techniques (ART) to create a new donor for stem cell transplantation. We address ethical literature, the medical and psychosocial impact on patient, donor, family, and medical caregivers, and the appropriate decision‐making process. We conclude that the use of ART to create a stem cell donor can be ethically acceptable. The decision to conceive a donor has medical and psychosocial implications. The family is the appropriate decision‐maker and must consider risks and benefits to all parties with input from medical caregivers. Pediatr Blood Cancer 2007;48:249–253. © 2006 Wiley‐Liss, Inc.