bluuebunny/crossref_metadata_2025_split huggingface dataset:
KAl(SO4)2×12H2O: An Efficient Catalyst for the Stereoselective Synthesis of cis‐Isoquinolonic Acids.
Authors: Azizian Javad , Mohammadi Ali A. , Karimi Ali R. , Mohammadizadeh Mohammad R. , Koohshari M. 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
The Facile Formation of Trioxanaphthacenes by a [4 + 2] Addition of Flavonols to 1,2‐Benzoquinone.
Authors: Kaizer Jozsef , Speier Gabor , Oesz Erzsebet , Giorgi Michel , Reglier Marius 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
An Efficient One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2‐ones Catalyzed by Methanesulfonic Acid.
Authors: Jin Tong‐Shou , Wang Huan‐Xin , Xing Chun‐Yong , Li Xiao‐Liu , Li Tong‐Shuang 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Stereoselective Intramolecular Hetero Diels—Alder Reactions of 1‐Oxa‐1,3‐butadienes: A Novel Approach for the Synthesis of Complex Annulated Uracils.
Authors: Devi Ipsita , Bhuyan Pulak J. 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
2‐C‐Branched Glycosides from 2′‐Carbonylalkyl 2‐O‐Ms(Ts)‐Glycosides. A Tandem SN2—SN2 Reaction via 1,2‐Cyclopropanated Sugars.
Authors: Shao Huawu , Ekthawatchai Sanchai , Wu Shih‐Hsiung , Zou Wei 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Highly Selective Synthesis of Bicyclic Quinolizidine Alkaloids and Their Analogues via Double RCM Reaction of N‐Alkynyl‐N‐(1,ω)‐alkadienyl Acrylamides.
Authors: Ma Shengming , Ni Bukuo , Liang Zhiqiang 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Various Types of Metal Complexes Based on Chelating β‐Diketones and Their Structural Analogues
Authors: Skopenko V. V. , Amirkhanov V. M. , Sliva T. Yu. , Vasilchenko I. S. , Anpilova E. L. , Garnovskii A. D. 
Published: January 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Lithium‐Batterien
Authors: Dierks Wiebke , Vennemann Hendrik 
Published: January 2005

Abstract„Ich finde, dass es schon irgendwie zum Allgemeinwissen gehört und es außerdem viel spannender ist, auch zu wissen was überhaupt passiert, wenn man einen Lithium‐Ionen Akku benutzt und sich nicht nur damit zufrieden zu geben, dass man ihn halt laden und entladen kann.”︁ Dieses sagte eine Schülerin auf die Frage, ob sie es wichtig fände zu wissen, wie ein Lithium‐Ionen‐Akkumulator funktioniere. Aus diesem Grund möchten wir in diesem Artikel im ersten Teil einige chemische Grundlagen der Lithium‐Batterien darlegen und anschließend eine Unterrichtsreihe vorstellen, mit der es gelingen kann, dieses aktuelle und alltagsnahe Thema in den Chemieunterricht zu integrieren.
Clinical presentation of delirium in patients undergoing hematopoietic stem cell transplantation
Authors: Fann Jesse R. , Alfano Catherine M. , Burington Bart E. , Roth‐Roemer Sari , Katon Wayne J. , Syrjala Karen L. 
Published: January 2005

AbstractBACKGROUNDDelirium is common in patients undergoing hematopoietic stem cell transplantation (HSCT) and is associated with considerable morbidity and excess mortality in diverse patient samples. Although delirium can be treated successfully, it is largely undiagnosed. Understanding the clinical presentation of delirium may help improve the recognition of delirium in these patients. In the current study, the authors investigated the clinical presentation of delirium in HSCT patients, including the time course of these symptoms and comorbid affective distress, fatigue, and pain.METHODSNinety patients ages 22–62 years were recruited prior to undergoing their first allogeneic or autologous HSCT. Delirium, distress, and pain symptom assessments were conducted prospectively 3 times per week from pretransplantation through Day 30 posttransplantation.RESULTSDelirium episodes occurred in 50% of patients and lasted approximately 10 days, with peak severity at the end of the second week posttransplantation. Factor analysis revealed three groups of delirium symptoms representing psychosis‐behavior, cognition, and mood‐consciousness. Delirium episodes were characterized by rapid onset of psychomotor and sleep‐wake cycle disturbance that persisted and cognitive symptoms that continued to worsen throughout much of the episode. Rises in psychosis‐behavior and cognitive symptoms predated the start of delirium episodes by ≈ 4 days. Affective distress and fatigue were common and appeared to be associated most with psychosis‐behavioral delirium symptoms.CONCLUSIONSThe results describe in detail the clinical presentation of delirium in patients undergoing HSCT. Affective distress and fatigue commonly were associated with delirium. These findings may aid clinicians in improving the recognition and treatment of delirium in this population and avoiding further morbidity and potential mortality. Cancer 2005. © 2005 American Cancer Society.
HER‐2/neu and p53 overexpression as biomarkers of breast carcinoma in women age 30 years and younger
Authors: Maru Dipen , Middleton Lavinia P. , Wang Sijan , Valero Vicente , Sahin Aysegul 
Published: January 2005

AbstractBACKGROUNDAlthough p53 and HER‐2/neu overexpression are found in 30% of breast carcinomas in women of all ages and are associated with high rates of lymph node metastases, their role in women age < 30 years has not been studied extensively.METHODSThe institutional breast cancer data base was searched to identify young women (23–30 years) with breast carcinoma. An immunohistochemical analysis was performed to determine estrogen receptor and progesterone receptor expression and p53 and HER‐2/neu overexpression. Positive staining for p53 was defined as nuclear staining in > 10% of tumor cells. HER‐2/neu membranous staining was graded as 0, 1 (incomplete, faint staining in > 10% of cells), 2 (weak‐to‐moderate, complete staining in > 10% of cells), or 3 (complete, strong staining in > 10% of cells). Fluorescence in situ hybridization (FISH) was performed on all samples with ≥ 2 and ≥ 3 results, and only FISH‐positive samples were classified as positive. The overexpression was correlated with clinicopathologic features.RESULTSAmong 44 patients, 1 patient had medullary carcinoma, and 1 had mixed ductal/lobular carcinoma. All remaining patients were diagnosed with invasive ductal carcinoma. The clinical stage was T1 in 5 patients, T2 in 24 patients, T3 in 10 patients, T4 in 4 patients, and unavailable in 1 patient. Positive p53 status was determined in 22 of 44 patients (50%), and positive HER‐2/neu status was determined in 18 of 41 patients (44%). Tumors with lymph node metastasis had a significantly greater incidence of HER‐2/neu overexpression (P = 0.04).CONCLUSIONSFrequent overexpression of HER‐2/neu and p53 was found in the patient population. HER‐2/neu overexpression was associated significantly with lymph node involvement and, thus, may be a marker for aggressive clinical behavior in patients with breast carcinoma age ≤ 30 years. Cancer 2005. © 2005 American Cancer Society
Absolute Rate Calculations: Atom and Proton Transfers in Hydrogen‐Bonded Systems
Authors: Barroso Mónica , Arnaut Luis G. , Formosinho Sebastião J. 
Published: January 2005

AbstractWe calculate energy barriers of atom‐ and proton‐transfer reactions in hydrogen‐bonded complexes in the gas phase. Our calculations do not involve adjustable parameters and are based on bond‐dissociation energies, ionization potentials, electron affinities, bond lengths, and vibration frequencies of the reactive bonds. The calculated barriers are in agreement with experimental data and high‐level ab initio calculations. We relate the height of the barrier with the molecular properties of the reactants and complexes. The structure of complexes with strong hydrogen bonds approaches that of the transition state, and substantially reduces the barrier height. We calculate the hydrogen‐abstraction rates in H‐bonded systems using the transition‐state theory with the semiclassical correction for tunneling, and show that they are in excellent agreement with the experimental data. H‐bonding leads to an increase in tunneling corrections at room temperature.
Graphite Powder and Multiwalled Carbon Nanotubes Chemically Modified with 4‐Nitrobenzylamine
Authors: Wildgoose Gregory G. , Wilkins Shelley J. , Williams Gareth R. , France Robert R. , Carnahan David L. , Jiang Li , Jones Timothy G. J. , Compton Richard G. 
Published: January 2005

AbstractWe demonstrate that graphite powder and multiwalled carbon nanotubes (MWCNTs) can be derivatised by 4‐nitrobenzylamine (4‐NBA) simply by stirring the graphite powder or MWCNTs in a solution of acetonitrile containing 10 mM 4‐NBA. We propose that 4‐NBA partially intercalates at localised edge‐plane or edge‐plane‐like defect sites and support this hypothesis with a range of experimental data provided by electrochemistry in both aqueous and nonaqueous media, electron microscopy and X‐ray powder diffraction.
The Interaction of Water‐Soluble Manganese Porphyrins with DNA Films and Their Electrocatalytic Properties with Hydrazine
Authors: Chen Shen‐Ming , Lu Ming‐Feng , Lin Kuo‐Chiang 
Published: January 2005

AbstractThe electrochemistry of water‐soluble manganese porphyrins (Mn(4‐TMPyP)) has been studied as an electrochemically‐active film on double‐stranded deoxyribonucleic acid (dsDNA) modified electrodes in solutions at various pH. An electrochemical quartz crystal microbalance and cyclic voltammetry were used to study the in situ deposition of DNA on gold disk electrodes, and Mn(4‐TMPyP) (manganese meso‐tetrakis‐(N‐methyl‐4‐pyridyl)porphyrin) deposition on DNA film modified electrodes. MnII(4‐TMPyP) (the reduced form) is more easily deposited on a DNA film than MnIII(4‐TMPyP) (the oxidized form). Electrodeposition of Mn(4‐TMPyP) can be performed in strong basic aqueous solutions, and shows two redox couples with electrochemically active voltammograms. The films can also be produced on glassy carbon, platinum, gold, and transparent semiconductor tin (IV) oxide electrodes. The Mn(4‐TMPyP)/DNA film was electrocatalytically oxidative for hydrazine, hydroxylamine, and SO$\rm{ {_{3}^{2-}}}$ in a basic aqueous solution through a Mn(IV) species. The electrocatalytic efficiency of MnIV(O)(4‐TMPyP) was observed to be greater than (OH)MnIV(O)(4‐TMPyP). Electrocatalytic oxidation by a Mn(4‐TMPyP) film as a catalyst for hydrazine oxidation is also discussed. This shows a new anodic peak current in the second segment after the positive scan during electrocatalytic oxidation, and is pH dependent.
Continouos Heavy Metal Monitoring System for Application in River and Seawater
Authors: Mikkelsen Øyvind , Skogvold Silje M. , Schrøder Knut H. 
Published: January 2005

AbstractAn automated voltammetric system using solid electrodes was investigated for continuous and on‐line remote monitoring of heavy metals in natural waters. Both a polluted river impacted by a copper mine, and costal seawater were monitored automatically every 30 minutes for six months. The huge difference in these two locations demonstrates the wide application range for this system. Results have been automatically monitored every thirty minutes for six months, and can be correlated against a range of parameters, e.g., season, flow of water, temperature, pH etc.
Electrochemical and Catalytic Properties of the Adenine Coenzymes FAD and Coenzyme A on Pyrolytic Graphite Electrodes
Authors: de‐los‐Santos‐Álvarez Noemí , Lobo‐Castañón María Jesús , Miranda‐Ordieres Arturo J. , Tuñón‐Blanco Paulino 
Published: January 2005

AbstractRedox properties of two coenzymes, flavin adenine dinucleotide (FAD) and coenzyme A (CoA) are studied on pyrolytic graphite electrodes. Both of them exhibit an oxidation process at about 1.2 V in pH 9, associated with the oxidation of their adenine moiety. The resulting adsorbed oxidation products have a common structure, an electroactive quinone‐imine that acts as efficient catalyst of the oxidation of NADH at low potentials. The influence of the structure on their electrochemical features in comparison with other adenine derivatives is studied. Finally, a modified electrode prepared with the oxidation product of CoA was used to determine NADH in a wide linear range (1×10−8–2.43×10−5 M) with a detection limit of 3 nM.
Bioelectrocatalysis of Plant Peroxidases Immobilized on Graphite in Aqueous and Mixed Solvent Media
Authors: Brusova Zuzana , Ferapontova Elena E. , Sakharov Ivan Yu. , Magner Edmond , Gorton Lo 
Published: January 2005

AbstractThe bioelectrocatalytic function of two plant peroxidases, horseradish peroxidase (HRP) and a newly purified royal palm tree‐leaf peroxidase (RPTP), was studied on graphite electrodes in aqueous buffer solutions, over the pH range 7.0–3.0, and in aqueous buffer solutions, at pH 6.0, containing different amounts of a polar organic cosolvent, i.e., ethanol and acetonitrile. The kinetics of direct and of mediated (using catechol as mediator) reduction of H2O2 at the HRP‐ and RPTP‐modified graphite electrodes were analyzed amperometrically at −50 mV(vs. Ag|AgCl|0.1 M KCl) in a flow‐through wall‐jet electrochemical system. Values of the apparent rate constant of the heterogeneous electron transfer between the enzyme and graphite, ks, the rate constant for enzymatic reduction of H2O2, k1, and the rate constant of mediated reduction of H2O2, k3, were determined using the modified Koutecky‐Levich approach. Analysis of the variation of the rate constants and the response of the peroxidase‐modified electrodes to H2O2 with pH and content of the organic cosolvent demonstrated that maximal peroxidase bioelectrocatalytic activity occurred at pH 5.0–6.0 and at concentrations of ethanol of 10–20% v/v. At a lower pH, higher concentrations of ethanol, and in aqueous solutions of acetonitrile, the bioelectrocatalytic activity of the peroxidase‐modified electrodes drastically decreased. However, contrary to the data for homogeneous catalysis, both peroxidases were bioelectrocatalytically active even in 95% organic co‐solvents, thus demonstrating a stabilizing effect of the enzyme immobilization on the bioelectrocatalytic performance of the peroxidases. RPTP immobilized on graphite demonstrated lower overall activity but a higher pH‐ and organic cosolvent‐stability than HRP.
A Study of Heavy Metal Complexation in Grape Juice
Authors: Salinas Íñigo , Esparza Irene , Gómez Sara , Santamaría Carolina , Fernández José M. 
Published: January 2005

AbstractDifferential pulse anodic stripping voltammetry, DPASV, has been used to monitor the initial stages of grape juice fermentation, focusing on Zn interactions with natural occurring ligands. Langmuir and Scatchard linearization methods have been employed. A 1 : 1 ratio has been found by either method; from Langmuir data analysis only one ligand population was found, while Scatchard approach gave rise to the detection of two ligand types. Both data analysis procedures led to the same total ligand concentration. When catechin was used as model ligand, a 1 : 1 ratio was found for Zn and also for Cu.
Visualization of the Reaction Zones Between Two Miscible Solutions with Potentiometric and Amperometric Microsensors
Authors: Schröck Konstanze , Schulte Albert , Schuhmann Wolfgang 
Published: January 2005

AbstractA strategy for visualizing the concentration gradients in the border zone between two miscible aqueous solutions of different composition is presented. To achieve this goal, potentiometric pH microsensors and disk‐shaped Pt microelectrode have been operated as scanning probes in a set‐up that combined conventional scanning electrochemical microscopy (SECM) equipment with an inverted optical microscope and a syringe pump for analyte injection. With the established system, complex gradients in proton concentration have been examined in the reaction zone between two aqueous solutions of different pH value, one of which being dispensed into the other at controlled flow rate. In addition to the local potentiometric measurements, Pt microelectrodes have been used as amperometric SECM tips to visualize the reaction zone at the diffuse boundary between a stream of H2O2 and a neighbouring catalase‐containing buffer solution.
Geomorphic and sedimentological signature of a two‐phase outburst ﬂood from moraine‐dammed Queen Bess Lake, British Columbia, Canada
Authors: Kershaw Jane A. , Clague John J. , Evans Stephen G. 
Published: January 2005

AbstractOn 12 August 1997, the lower part of Diadem Glacier in the southern Coast Mountains of British Columbia fell into Queen Bess Lake and produced a train of large waves. The waves overtopped the broad end moraine at the east end of the lake and ﬂooded the valley of the west fork of Nostetuko River. The displacement waves also incised the outﬂow channel across the moraine. Stratigraphic and sedimentologic evidence supports the conclusion that the ﬂood had two phases, one related to wave overtopping and a second to breach formation. Empirical equations were used to calculate the peak discharge of the ﬂood at various points along the west fork of the Nostetuko valley and to describe the attenuation of the ﬂood wave. The velocity of the ﬂood was also calculated to determine the time it took for the ﬂood to reach the main fork of Nostetuko River. The highest peak discharges were achieved in the upper reach of the valley during the displacement phase of the ﬂood. Peak discharge declined rapidly just below the moraine dam, with little change thereafter for approximately 7 km. Empirical formulae and boulder measurements indicate a rise in peak discharge in the lower part of the west fork valley. We suggest that ﬂow in the upper part of the valley records the passage of two separate ﬂood peaks and that the rise in discharge in the lower part of the valley is due to amalgamation of the wave and breach peaks. Hydraulic ponding in conﬁned reaches of the valley extended the duration of the ﬂood. In addition, erosion of vegetation and sediment in the channel and valley sides may also have exerted an inﬂuence on the duration and nature of ﬂooding. Sediments were deposited both upstream and downstream of channel constrictions and on a large fan extending out into the trunk Nostetuko River valley. This study extends our understanding of the variety and complexity of outburst ﬂoods from naturally dammed lakes. It also shows that simple empirical and other models for estimating peak discharges of outburst ﬂoods are likely to yield erroneous results. Copyright © 2005 John Wiley & Sons, Ltd.
The contribution of geoarchaeology to understanding the environmental history and archaeological resources of the Trent Valley, U.K.
Authors: Howard Andy J. 
Published: January 2005

AbstractThis paper provides a review of the contribution that geoarchaeological research has played in elucidating the landscape history of the Trent Valley, U.K. Ameliorating climate in the immediate postglacial led to the expansion of mixed deciduous woodland across the valley floor and the development of an anastomosing channel. In the Lower Trent, fluvial and vegetation development may have been influenced by sea‐level change. Around 4000 B.C., the character of the valley floor changed, demonstrated by the dating of tree trunks interbedded within gravel deposits. Synchronicity of changing geomorphological and hydrological processes is suggested, and, while the causal mechanism of this change are not fully understood, tree trunks which were clearly felled have been identified in the valley and provide significant evidence. The later prehistoric and historic archaeological remains, including fishweirs, bridges, and mill dams, point to increasing human activity, and environmental evidence documents the increasing effects of agriculture on the catchment. © 2005 Wiley Periodicals, Inc.
Erosion modeling of past land‐use practices in the Fiume di Sotto di Troina river valley, north‐central Sicily
Authors: Ayala Gianna , French Charly 
Published: January 2005

AbstractThe chronology and pattern of Holocene landscape development in the Nebrodi Mountains of north‐central Sicily, seen in valley alluviation and the pedological record, has been investigated in the Fiume di Sotto di Troina valley. Intensive geomorphological survey has revealed three phases of alluvial aggradation reflecting increased hillslope disturbance during the late Pleistocene and Holocene. The results of sediment analyses, archaeological survey, and literary evidence were combined in a Geographical Information System (GIS) in order to model the potential erosion caused by different land‐use practices throughout history. This paper presents the erosion model used to investigate possible Roman land‐use practices and their effects on landscape change as documented in the catchment basin. The results of the model support a correlation between intensive pastoralism and the erosional phases documented in the sedimentary record. © 2005 Wiley Periodicals, Inc.
Recent (1999–2003) Canadian research on contemporary processes of river erosion and sedimentation, and river mechanics
Authors: de Boer D. H. , Hassan M. A. , MacVicar B. , Stone M. 
Published: January 2005

AbstractContributions by Canadian fluvial geomorphologists between 1999 and 2003 are discussed under four major themes: sediment yield and sediment dynamics of large rivers; cohesive sediment transport; turbulent flow structure and sediment transport; and bed material transport and channel morphology. The paper concludes with a section on recent technical advances. During the review period, substantial progress has been made in investigating the details of fluvial processes at relatively small scales. Examples of this emphasis are the studies of flow structure, turbulence characteristics and bedload transport, which continue to form central themes in fluvial research in Canada. Translating the knowledge of small‐scale, process‐related research to an understanding of the behaviour of large‐scale fluvial systems, however, continues to be a formidable challenge. Models play a prominent role in elucidating the link between small‐scale processes and large‐scale fluvial geomorphology, and, as a result, a number of papers describing models and modelling results have been published during the review period. In addition, a number of investigators are now approaching the problem by directly investigating changes in the system of interest at larger scales, e.g. a channel reach over tens of years, and attempting to infer what processes may have led to the result. It is to be expected that these complementary approaches will contribute to an increased understanding of fluvial systems at a variety of spatial and temporal scales. Copyright © 2005 John Wiley & Sons, Ltd.