bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electroanalytical Chemistry with Carbon Film Electrodes and Micro and Nano-Structured Carbon Film-Based Electrodes
Authors: Niwa Osamu 
Published: April 2005

Abstract
The recent development of electroanalysis using carbon film electrodes and micro and nano-structured carbon film based electrodes is reviewed. Graphite-like carbon film was synthesized by various methods such as thermal chemical vapor deposition and the thermolysis of organic polymers. Highly stable diamond film electrodes with a wide potential window have been synthesized by using the plasma CVD process and then employed for electroanalysis. A carbon film consisting of electron cyclotron resonance (ECR) sputter-deposited carbon films containing a large portion of sp3 bonds was introduced. The film makes it possible to detect analytes with higher oxidation potential or electroactive species that foul the electrode surface after oxidation. ECR carbon film can be deposited at low temperature and is conductive without doping. Graphite-like carbon films have been formed in order to construct various microelectrodes and microarray electrodes by using photolithography and dry etching methods to meet the requirements for improving the detection limit and for miniaturizing electrochemical detectors for small volume samples. For example, carbon film fabricated into an interdigitated array (IDA) electrode has a very low detection limit for biochemicals such as catecholamines when used as an electrochemical detector for high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). In contrast, composite carbon films containing various metal nanoparticles can be used for many analytes, including hydrogen peroxide and sugars. The films are deposited by the RF co-sputtering of metal and carbon. This is unlike other preparation methods such as the thermolysis of a polymer–metal complex or the electroplating of metal particles onto carbon film. The obtained carbon film contains 2–5 nm metal particles such as Pt, Ni, Cu, and Ir. The highly sensitive and extremely stable detection of hydrogen peroxide, which is known to be the product of various oxidase enzymatic reactions, was achieved with sputter-deposited carbon film in which Pt nano-particles were dispersed. In contrast, carbon films containing dispersed Ni and Cu nanoparticles provide a high electrocatalytic current for sugars such as glucose and lactose in alkaline solution. By using the film as a detection electrode for HPLC, one can obtain a lower detection limit for several sugars than when using bulk metal electrodes.
Growth of AOT Reversed Micelles and the Solvent Effect Investigated by Dielectric and Light-Scattering Measurements
Authors: Tanaka Reiji , Yokoyama Takuya , Sameshima Kaori , Kawase Tokuzo 
Published: April 2005

Abstract
The relative permittivity (εr) and the conductivity (κ) at a frequency (f) of 50 kHz, and the dynamic light-scattering were measured for ternary systems of (AOT + r·H2O) solved in cyclohexane, heptane, octane, decane, and dodecane at a temperature of 298.15 K as a function of the amount ratio (r) of water to AOT (r = [H2O]/[AOT]) up to the onset of percolation. The molality (m) of AOT for those solutions was 0.15 mol kg−1, and increased to 0.30 mol kg−1 for solutions with dodecane. By increasing r, spherical reversed micelles were formed at r ≈ 6 in straight-chain hydrocarbons. The light-scattering measurements indicated that the mean hydrodynamic diameter of the micelles increased with increasing r, showing a sigmoid curve. The growth of micelles was promoted in a longer chain hydrocarbon. The percolation transition occurred as the particles grew to a critical diameter of about 50 nm. On the other hand, the growth of particles in c-hexane was moderate, and percolation did not occur up to r = 90, where the solution turned turbid. The growth of particles found from light-scattering measurements was well correlated to dielectric observations.
Syntheses, Crystal Structures of Mo–S Clusters [Mo3S4(dtp)3(L)]2[μ-OOC(CH2)nCOO-μ] (L = dmf, dmso; n = 3, 4) and Their Supramolecular Architectures
Authors: Tang Yan-Hong , Qin Ye-Yan , Li Zhao-Ji , Zhang Jian , Kang Yao , Hu Rui-Feng , Wen Yi-Hang , Cheng Jian-Kai , Yao Yuan-Gen 
Published: April 2005

Abstract
The substitution reaction of [Mo3S4(dtp)3(ClCH2COO)(py)] (dtp = diethyl dithiophosphate) or [Mo3S4(dtp)4(H2O)] with adipic acid or glutaric acid in N,N′-dimethylformamide (dmf) or dimethyl sulfoxide (dmso) dimerized two discrete Mo3S4 clusters into novel Mo(IV) cluster compounds [Mo3S4(dtp)3(L)]2[μ-OOC(CH2)nCOO-μ] (L = dmf, n = 4 for 1, n = 3 for 2; L = dmso, n = 3 for 3). Their structures have been determined by X-ray crystallography and spectroscopically characterized. Each molecule of these clusters consists of two incomplete cubane-type [Mo3S4(dtp)3(L)] units, and each unit is respectively coordinated to one dicarboxylate group of the same dicarboxylic acid. Intermolecular S···S and C–H···S contacts, observed in the crystal packing diagram, establish three infinite two-dimensional supramolecular architectures.
Incorporation of Ethylenediamine as a Bi-layer in the Interlayer Space of Tetratitanic Acid by Re-stacking Exfoliated Nanosheets
Authors: Sugimoto Wataru , Ohuchi Kazunori , Murakami Yasushi , Takasu Yoshio 
Published: April 2005

Abstract
The reaction of ethylenediamine with a colloidal suspension containing exfoliated H2Ti4O9 nanosheets was studied. Characterization of the product by X-ray diffraction, thermogravimetry-differential thermal analysis, elemental analysis, and solid-state 13C NMR revealed that two types of ethylenediamine–H2Ti4O9 intercalation compounds, namely, compounds with ethylenediamine in a mono-layer or a bi-layer arrangement, could be prepared depending on the synthetic conditions. The latter composite material is a novel intercalation compound with the ethylenediamine arranged in a bi-layer with one amine group attached to the interlayer surface of H2Ti4O9 as an ammonium cation (–NH3+) and the other group present in the interlayer space in a neutral state (–NH2).
Association of trans-[PdCl2(NH=CPh2-κN)2] via Intermolecular N–H···Cl Hydrogen Bonding in the Solid State and in Solution
Authors: Kuwabara Junpei , Takeuchi Daisuke , Osakada Kohtaro 
Published: April 2005

Abstract
The crystal structure of a new complex, trans-[PdCl2(NH=CPh2-κN)2], shows an association of the two molecules via intermolecular N–H···Cl hydrogen bonds. The 1H NMR signal of the N–H hydrogen in CDCl3 changes its position depending on the concentration and temperature of the solution.
Stereoselective Synthesis of 19-Hydroxytaxoid by Utilizing Samarium(II) Iodide-Mediated Double Aldol Cyclization
Authors: Ogawa Yasuyuki , Kuroda Kiichi , Matsuo Jun-ichi , Mukaiyama Teruaki 
Published: April 2005

Abstract
The stereoselective synthesis of new 19-hydroxytaxoid 36, possessing a double-aldol skeleton was achieved by way of B to BC to ABC ring construction. Optically active 8-membered ring 6 corresponding to the B-ring of 19-hydroxytaxol has been synthesized in high yield from epoxyketo aldehyde 8 by intramolecular samarium(II) iodide-mediated double aldol cyclization. The bicyclic compound 5 corresponding to the BC ring system was prepared from the 8-membered ring 6 by successive trimethylaluminium-assisted stereoselective conjugated addition and intramolecular samarium(II) iodide-mediated double aldol cyclization. The ABC-ring system 4 was constructed by stereoselective homoallylation and pinacol coupling cyclization with low-valent titanium. The synthesis of new 19-hydroxytaxoid 36 was accomplished from ABC ring system 4 by olefination of vicinal diol unit.
Generation of Superoxide in a Water-Soluble Model System with FeTMPyP
Authors: Nakano Taku , Ohto Kanae , Okafuji Fumito , Mori Yoshihiro , Kakuda Hiroko , Hatanaka Yasumaru , Masuoka Noriyoshi 
Published: April 2005

Abstract
In a model system of a water-soluble hemin, tetrakis(4-methylpyridyl)porphinatoiron(III) pentachloride (FeTMPyPCl5), with 3-methyl-2-benzothiazolinone hydrazone (MBTH), superoxide anion radical (O2•−), hydrogen peroxide, and then hydroxyl radical were generated in a phosphate buffer solution (pH 6.0–7.5) under aerobic conditions. The hemin was degraded in this system. The reactive oxygen species were deduced from inhibition of the degradation by adding SOD and catalase, and one of them was trapped by 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a DMPO–hydroxyl radical adduct, which was detected by ESR. The mechanism for activating dioxygen and the degradation of hemin was examined, and it was proposed to be the initial one-electron reduction of hemin by MBTH forming a dioxygen complex and liberating superoxide as one of the routes during the reduction–autoxidation cycle in aqueous media.
Optically Active Seleninic Acid: Isolation, Absolute Configuration, Stability, and Chiral Crystallization
Authors: Nakashima Yusuke , Shimizu Toshio , Hirabayashi Kazunori , Yasui Masanori , Nakazato Masaki , Iwasaki Fujiko , Kamigata Nobumasa 
Published: April 2005

Abstract
Each optical isomer of methaneseleninic acid (1a) was isolated as chiral crystals by recrystallization from methanol/toluene. The absolute configuration of one of the enantiomers was determined by X-ray crystallographic analysis, and the relationship between the absolute configuration and the circular dichroism spectra of 1a was clarified. The optically active seleninic acid (R)-1a was stable toward racemization in the solid state, although it racemized very rapidly in solution. Each enantiomer of 1a was obtained in bulk by chiral crystallization in the presence of a seed crystal or chiral solvents. The absolute configuration of optically active methanesulfinic acid (4) was also assigned by comparing its circular dichroism spectra with those of 1a.
Intermolecular Communication on Lipid Bilayer Membrane. Tuning of Enzymatic Activity with Phase Transition of the Matrix Membranes
Authors: Tian Wen-Jie , Sasaki Yoshihiro , Fan Sheng-Di , Kikuchi Jun-ichi 
Published: April 2005

Abstract
A molecular device, in which the catalytic activity of lactate dehydrogenase was controlled by a response of ditopic molecular recognition of a lipid signal, was constructed on lipid bilayer membranes. The enzymatic activity was tuned up sensitively through phase transition of the matrix membrane as a platform for the intermolecular communication.
Novel Low-Molecular-Weight Gelators Based on Azobenzene Containing l-Amino Acids
Authors: Inoue Daisaku , Suzuki Masahiro , Shirai Hirofusa , Hanabusa Kenji 
Published: April 2005

Abstract
A series of azobenzene derivatives containing glycine, l-alanine, l-valine, l-leucine, and l-isoleucine were synthesized and their gelation properties were examined. Although the azobenzene derivatives containing glycine, l-alanine, and l-leucine exhibited very low gelation abilities, other compounds of l-isoleucine and l-valine acted as good gelators that formed organogels in many organic solvents and oils at relatively low concentrations. The electron microscopic observation demonstrated that a three-dimensional network was created by entanglement of self-assembled nanofibers. Furthermore, the spectroscopic studies suggested that the gelator molecules self-assembled into the nanofibers through hydrogen bonding and π–π interactions, including the H-aggregation mode of the azobenzene segments.
Analysis of Minor Hemoglobins by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry
Authors: Zurbriggen Karin , Schmugge Markus , Schmid Marlis , Durka Silke , Kleinert Peter , Kuster Thomas , Heizmann Claus W , Troxler Heinz 
Published: April 2005

AbstractBackground: Hemoglobin (Hb) heterogeneity arises mainly from posttranslational modifications of the globin chains, and cation-exchange chromatography reveals falsely increased concentrations of some minor Hbs in the presence of abnormal Hbs. Here we describe a method for identification of the globin chains and their posttranslational modifications contained in the Hb fractions.Methods: We used cation-exchange HPLC (PolyCAT A column) for separation of Hb fractions and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for analysis of the separated globin chains. Globin chains were identified by their molecular masses. Posttranslational modifications of globin chains were identified by digestion of the proteins with endoproteinase V8 before MALDI-TOF MS of the resulting peptides.Results: Analysis of the HbA2 fractions of patients with HbS revealed 4 different globin chains. We found, in addition to the expected α- and δ-chains, the carbamylated α- and the βS-chains. Additionally, we analyzed HbH, Hb Barts, HbA1b, pre-HbA1c, HbA1c, HbF1, HbF, HbA1d3a, HbA1d3b, HbA2, and HbC1 fractions from control and pathologic blood samples. We identified several posttranslational modifications of the globin chains, such as pyruvatization, glycation, acetylation, carbamylation, and acetaldehyde adduct formation.Conclusions: The native and posttranslationally modified globin chains in minor and major Hbs are unambiguously identified by MALDI-TOF MS. A minor Hb containing the carbamylated α- and the βS-chain elutes at the same time as normal HbA2 (α2δ2) and thus leads to falsely increased HbA2 values in patients with HbS when blood is analyzed with PolyCAT A chromatography.
Developing Science in Developing Countries: The Harvard College Observatory and the Establishment of Modern Astrophysics in Mexico
Authors: Bartolucci Jorge 
Published: April 2005

The 1942 creation of the National Astrophysical Observatory of Tonantzintla, Puebla, marked the beginning of the later establishment of modern astrophysics in Mexico. This advancement was made possible through the support given by the Harvard College Observatory to a group of young Mexican scientists who worked very hard to integrate their country into the international scientific community. Despite the efforts made by Mexican politicians and astronomers before 1940 to build scientific institutions to promote the progress of science in the country, public and private support was sporadic, fragmented, weak and directionless. What happened in the 1940s that made it possible to overcome these obstacles? According to this analysis, success can be explained as a consequence of the close interaction between Harlow Shapley and Luis E. Erro under very singular historical circumstances. Since their collaboration took place within the context of the Second World War, the influence of geopolitical affairs must be underlined. As a case study, the essay highlights the presence of social and historical factors that particularized the process of more globalized transference of modern science outside Western Europe and the United States.
El establecimiento de la astronomía moderna en México fue una historia de desventuras. A pesar de los sucesivos esfuerzos iniciados en 1842 para erigir un observatorio nacional que promoviese el progreso de la ciencia astronómica, el respaldo público y privado fue esporádico, fragmentario, débil y errático. Con la fundación del Observatorio Astronómico Nacional en 1878, las condiciones para hacer estudios astronómicos mejoraron; sin embargo, las circunstancias económicas, políticas e intelectuales de la época no fueron las adecuadas para que los astrónomos locales se incorporaran al vigoroso proceso de crecimiento y consolidación de la astrofísica moderna. Esto cambió apenas en 1942, con la fundación del Observatorio Astrofísico de Tonantzintla. En esa oportunidad se sentaron las bases para el establecimiento de la astrofísica en México. La construcción de este observatorio fue posible gracias a la solidaridad del director del Observatorio de la Universidad de Harvard, Harlow Shapley, y al apoyo incondicional del gobierno de México a un grupo de jóvenes científicos mexicanos, encabezado por Luis Enrique Erro, que trabajaron arduamente para actualizar la astronomía local. Dicho proceso tuvo lugar entre 1938 y 1942, en medio de una situación interna muy particular de la política mexicana y de los problemas geopolíticos planteados por la Segunda Guerra Mundial.
The Political Origins of Social Security in Mexico during the Cárdenas and Ávila Camacho Administrations
Authors: Dion Michelle 
Published: April 2005

This study compares efforts to adopt social insurance legislation in the administrations of Lázaro Cárdenas and Manuel Ávila Camacho in Mexico to explain the political origins of the welfare state in Latin America. The author argues that the adoption and implementation of social insurance in Mexico was the outcome of an implicit bargain between organized labor and the state following the 1940 presidential election. This bargain signifies the rebuilding by the Ávila Camacho administration of the cross-class coalition originally designed by President Cárdenas and jeopardized by the nationalization of petroleum and presidential succession struggles of the late 1930s.Este trabajo compara esfuerzos a implantar legislación del seguro social en las administraciones de Lázaro Cárdenas y de Manuel Ávila Camacho en México para explicar los orígenes políticos del Estado de bienestar en América Latina. La autora discute que la adopción y la implantación del seguro social en México fueron resultados de un negocio implícito entre la clase trabajadora organizada y el Estado que seguía la elección presidencial de 1940. Este negocio significa la reconstrucción por la administración de Ávila Camacho de la coalición de clases diseñada por presidente Cárdenas y comprometida originalmente por la nacionalización del petróleo y de las luchas de la sucesión presidencial de los finales de los 30s.
Effects of Waterfall Dimensions and Light Intensity on Age‐0 Brook Trout Jumping Performance
Authors: Brandt Mandi M. , Holloway J. Preston , Myrick Christopher A. , Kondratieff Matthew C. 
Published: April 2005

AbstractWe conducted three experiments to understand the effects of (1) waterfall design (width, height, and plunge pool depth) and (2) light intensity on the ability of age‐0 brook trout Salvelinus fontinalis to successfully jump over small waterfalls or vertical obstacles, such as pool‐and‐weir fishways. We measured the jumping performance of brook trout as a function of waterfall height (2–24 cm), plunge pool depth (8–18 cm), and fish size (total length (TL), mm). Waterfall height and TL had the largest effects on jumping performance. Maximum heights jumped decreased as waterfall height increased or TL decreased. Our second experiment measured the effects of waterfall widths of 10, 20, and 30 cm on age‐0 brook trout jumping ability for a fixed waterfall height of 20 cm and a plunge pool depth of 40 cm. Significantly fewer fish jumped through the 10‐cm‐wide waterfall than through either the 20‐ or 30‐cm‐wide waterfalls. Our third experiment measured the jumping success of brook trout at light levels of 0, 0.23, and 1.70 lx/μA. Brook trout successfully jumped over 4‐ and 20‐cm‐high waterfalls at all light intensities, providing evidence that they can see very well under low light conditions and may also use senses like the acoustico‐lateralis system to help them negotiate obstacles. We conclude that narrow waterfalls with heights more than three body lengths and shallow plunge pools will probably restrict the movement of age‐0 brook trout, while light intensity does not appear to have much of an impact on their movements.
Preoperative Assessment of Surgical Risk in Oncogeriatric Patients
Authors: Audisio Riccardo A. , Ramesh Hodigere , Longo Walter E. , Zbar Andrew P. , Pope Daniel 
Published: April 2005

Abstract
Cancer is a prevalent disease in our aging population; however, few oncologists are familiar with caring for oncogeriatric patients. Surgery is presently the treatment of choice for most solid tumors, but it is frequently delivered in a suboptimal way in this patient subsetting. Undertreatment is often justified with the concern of an unsustainable toxicity, while overtreatment can be related to the lack of knowledge in optimizing preoperative risk assessment. To draw new light on this issue, several surgeons presented their series, providing hard evidence that surgical options can be offered to the elderly with cancer, with only a limited postoperative mortality and morbidity. As it is likely that much of these data suffer from selection bias, we concentrated on Comprehensive Geriatric Assessment (CGA), which can add substantial information on the functional assessment of elderly cancer patients. A validated instrument such as the CGA allows a comparison of series, predicting short-term surgical outcomes more precisely, and offers appropriate information when consenting elderly patients. Preoperative Assessment of Cancer in the Elderly is a prospective international study conceived and launched to outline the fitness of elderly surgical patients with malignant tumors. This paper reports on preliminary results and analysis from the ongoing study.
T-Cell Lymphoma of the Rectum in a Patient with AIDS and Hepatitis C: A Case Report and Discussion
Authors: Tisdale Gus , Mahadevan Anand , Matthews Richard H. 
Published: April 2005

Abstract
Primary T-cell non-Hodgkin's lymphoma (NHL) occurring in the context of acquired immune deficiency syndrome (AIDS) is uncommon. Here, we report and discuss such a case presenting in the rectum, and review relevant literature. Although typical in some respects, the case is, in other ways, somewhat unusual for an AIDS-related NHL (ARL); ARL tends to be B cell and advanced stage and our case was T cell and stage IE. In addition, the patient suffered from concomitant cirrhosis related to hepatitis C. Chemotherapeutic options for ARL were limited early in the AIDS epidemic due to poor tolerability. Although this has largely been mitigated by the advent of highly active antiretroviral therapy, our patient eventually suffered complications of chemotherapy, apparently related more to his liver disease than to either his lymphoma or AIDS, that ultimately brought about his demise.
Toxicity assessment of environmentally relevant pollutant mixtures using a heuristic model
Authors: Olmstead Allen W. , LeBlanc Gerald A. 
Published: April 2005

Abstract
In this study, 9 chemicals were chosen from a recent report on surface water concentrations of a variety of xenobiotics to test the hypothesis that the toxicity of chemical mixtures could be estimated using a model based on the toxicity of the individual chemicals. Concentration-response curves for the endpoints of lifespan, growth rate, and fecundity were generated for each chemical experimentally using the crustacean, Daphnia magna. From this data, a mathematical model for the combined toxicity of these chemicals was generated that merged the concepts of concentration addition and independent joint action. Toxicity of a mixture was modeled at various levels at which the ratio of the chemicals within the mixture was maintained at that reported for median detected environmental levels. Toxicity of the mixture was then determined experimentally and compared to model predictions. The model accurately predicted the most sensitive endpoint, as well as the lowest toxic effect level of the mixture. Results demonstrated that, for this mixture of chemicals, toxicity was not influenced significantly by interactions among the chemicals and a single constituent dominated toxicity. According to model predictions and experimental results, the median detected environmental concentrations of chemicals constituting this mixture provided no margin of safety.