bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Bifunctionalized Ordered Mesoporous Materials
Authors: Zhang W.‐H. , Lu X.‐B. , Xiu J.‐H. , Hua Z.‐L. , Zhang L.‐X. , Robertson M. , Shi J.‐L. , Yan D.‐S. , Holmes J. D. 
Published: June 2004

AbstractDirect synthesis (co‐condensation reaction) and post‐synthesis reaction (grafting) are combined for the first time to efficiently fabricate bifunctionalized ordered mesoporous materials (OMMs). Ethylenediamine‐containing OMMs (ED‐MCM‐41) were first synthesized via direct synthesis and then further modified by the phenyl (PH) group in a supercritical fluid (SCF) medium via grafting reaction, resulting in OMMs with ED and PH groups (PH‐ED‐MCM‐41). X‐ray diffraction (XRD) patterns, N2 sorption properties, transmission electron microscopy (TEM), 29Si and 13C magic angle spinning (MAS) NMR, chemical analysis, and hydrothermal treatment were used to characterize the bifunctionalized materials. Experiments show that bifunctionalized OMMs can be efficiently prepared by modifying the directly synthesized monofunctionalized OMMs via grafting reaction in a supercritical fluid medium. Both functional groups are distributed uniformly at the surfaces. The advantage of bifunctionalized OMMs over monofunctionalized OMMs was illustrated by introducing thiol groups into ED‐MCM‐41 materials and the subsequent formation of CdS nanocrystals inside thiol‐ and ED‐functionalized MCM‐41 (HS‐ED‐MC‐41). Because of the variety of the functional groups that can be introduced into OMMs by direct synthesis or post‐synthesis reaction, it is expected that the present strategy could provide a generally applicable approach to the design of OMMs with two functional groups.
Reliable Monolayer‐Template Patterning of SnO2 Thin Films from Aqueous Solution and Their Hydrogen‐Sensing Properties
Authors: Shirahata N. , Shin W. , Murayama N. , Hozumi A. , Yokogawa Y. , Kameyama T. , Masuda Y. , Koumoto K. 
Published: June 2004

AbstractWe demonstrate a novel lithographic technique utilizing a solvent to fabricate a chemically based semiconductor microdevice from an aqueous solution. According to this technique, SnO2 thin film could be integrated onto predefined sites on a SiO2/Si wafer. A patterned octadecyltrimethoxysilane self‐assembled monolayer (ODS‐SAM) was prepared by vacuum ultraviolet (VUV) irradiation through a photomask to use as a template for the fabrication of a micropatterned SnO2 thin film on the SiO2/Si surface. A Sn‐based thin film was then deposited onto the entire surface of the ODS template from an aqueous solution containing 0.03 mol L–1 of SnCl2·2H2O at 60 °C for 16 h in an ambient atmosphere. The thin film deposited on the methyl‐terminated area of the template was then peeled using an ultrasonic rinse in anhydrous toluene for 30 min, while the film deposited on the silanol area remained intact and undamaged. Rinsing in hydrophilic solvents did not facilitate peeling of the thin film from the methyl‐terminated area. We succeeded by this process in obtaining a high‐resolution, micropatterned Sn‐based thin film on an ODS‐SAM template on Si. The as‐deposited film was composed of fine Sn‐based particles. The sensitivity of this SnO2 thin film to H2 gas increases linearly with improving crystallinity. The effectiveness of anhydrous toluene as a rinse in solution lithography is discussed from the viewpoint of the high hydrophobic affinity between the rinse solvent and the terminal groups in the monolayer template.
Age at menarche and age of onset of pubertal characteristics in 6–14‐year‐old girls from the Province of L'Aquila (Abruzzo, Italy)
Authors: Danubio Maria Enrica , de Simone Michele , Vecchi Francesco , Amicone Elisa , Altobelli Emma , Gruppioni Giorgio 
Published: June 2004

AbstractThe present study is part of a research project on growth models of children in an area of central‐southern Italy. It analyzes the phases of pubertal breast development (BD) in 397 girls, pubic hair development (PHD) in 399 girls, and menarche in 583 girls from 6–14 years old. The status quo method was used to evaluate the age at menarche. Probit analysis was used to analyze the data for all three variables. The onset of BD and PHD (Tanner stage 2) occurs at age 7 in 6.1% of girls. Passage to stage 3 of one or both secondary sexual characteristics occurs at age 10 in 8.5% of girls. Comparison with data from the United States shows higher percentages of American white girls in stage 2 (or greater) of both characteristics at any age. The mean (median) age of onset (Tanner stage 2) of BD or PHD or both of them is 9.96 years. The passage to stage 3 occurs at age 12.36 for BD (95% confidence interval: 1.36 years) and at age 12.10 for PHD (95% confidence interval: 0.51 years). The mean age at menarche is 12.55 years, in general agreement with other values found in Italy. Sexual maturation at any considered stage for both pubertal characteristics is generally in line with literature data concerning other Mediterranean and industrialized countries or countries in which the demographic transition is in an advanced phase. It does not show a significant earlier onset. The evidence emerging from the general project suggests that the secular trend is still in progress in this region of Italy. Am. J. Hum. Biol. 16:470–478, 2004. © 2004 Wiley‐Liss, Inc.
Recent decline in age at menarche: The Fels Longitudinal Study
Authors: Demerath Ellen W. , Towne Bradford , Chumlea W. Cameron , Sun Shumei S. , Czerwinski Stefan A. , Remsberg Karen E. , Siervogel Roger M. 
Published: June 2004

AbstractA number of recent reports suggest that the average age at menarche of US girls has declined over the past 20 years. Because the putative declines in the age at menarche are concurrent with increases in childhood body mass index (BMI), it has been suggested that these two trends may be causally linked. We examined differences in mean age of menarche in Fels Longitudinal Study girls who were born in six 10‐year birth cohorts (1930s, 1940s, 1950s, 1960s, 1970s, and 1980s) and simultaneous cohort changes in mean BMI measured cross‐sectionally at selected ages from 3–35 years (n = 371). Girls born in the 1980s had a mean age at menarche of 12.34 years, which was ∼3–6 months earlier than that of girls born previously (P < 0.001). While the mean BMI values at ages 25 and 35 generally increased from the 1930s to the 1970s, the mean BMI during childhood and adolescence remained constant across the six birth cohorts. In summary, we found no evidence that the recent decline in the age at menarche in the Fels Longitudinal Study girls was reflected in concurrent increases in BMI at any point in childhood or adolescence. Conversely, girls born in the 1960s and 1970s have subsequently become heavier in young and mid‐adulthood than were girls from earlier birth cohorts, without any concurrent change in the mean age at menarche over that time period. These two findings suggest that population‐level shifts in BMI and the timing of menarche are largely independent, although sometimes coincident, processes. Am. J. Hum. Biol. 16:453–457, 2004. © 2004 Wiley‐Liss, Inc.
Boas and beyond: Migration and craniometric variation
Authors: Relethford John H. 
Published: June 2004

AbstractMigration is expected to affect craniometric variation in three ways: 1) movement into a different environment leading to developmental plasticity; 2) movement into a different environment followed by in situ adaptation through natural selection; and 3) changes in among‐group differentiation and genetic distance through the action of gene flow. The relative influence of these three factors has been argued in the literature, most recently in a series of articles debating the statistical and biological significance of Boas's immigration studies as they relate to cranial plasticity. The Boas debate is discussed within the broader context of debate over genetic and environmental influences on craniometric variation. Additional examples are provided from an ongoing study of global craniometric variation. Although developmental plasticity and climatic adaptation have had an impact on craniometric variation, these factors tend not to erase, or even obscure greatly, underlying patterns of population structure and history that fit a neutral model of quantitative variation. Thus, craniometric data can be used to explore questions of gene flow and genetic affinity. Am. J. Hum. Biol. 16:379–386, 2004. © 2004 Wiley‐Liss, Inc.
History of migration studies in biological anthropology
Authors: Mascie‐Taylor C.G. Nicholas , Little Michael A. 
Published: June 2004

AbstractThe earliest studies of human biological factors in migration in which a clear research design was employed date back to the early 20th century in the United States. Maurice Fishberg's study of Jewish migrants, published in 1905, antedated the classic study of Franz Boas initiated in 1908. There have been two main approaches. The first approach examined the impact of migration in relation to changing environment and the importance of environmental plasticity. For example, Fishberg reported that migrants had offspring different in stature from themselves and with differences thought to be due to improvements in the environment, although some selection of genetically determined traits was suggested. Subsequently, a number of research designs have been used, ranging from Boas's simple design of sedente (nonmigrant) adults and children compared with first‐ and second‐generation migrants; Shapiro's extension of this study in Japanese migrants to Hawai'i; Goldstein's four‐fold comparison of Mexican sedentes and their offspring in Mexico, and migrants to the USA and their offspring in the USA; and Lasker's extension of Goldstein's Mexican study by including comparison of sedentes with returning emigrants. More sophisticated designs were used by Harrison and Baker in examining altitude effects and changes in subsistence and lifestyle during the 1960s through to the 1980s. The second approach has focused on the effect of migration on gene flow. For example, the clinal variation of ABO blood groups in Europe and Australia is generally purported to result from past migration, although increasing random migration for blood groups is likely to eliminate clinal variation. Migration has usually been considered from a spatial (geographic) perspective, but more recent studies have also investigated the impact of social or occupational movement (social mobility) alone, or in combination with geographic migration, and tested whether such movements are selective or random for a number of biological traits. Am. J. Hum. Biol. 16:365–378, 2004. © 2004 Wiley‐Liss, Inc.
Zur Genauigkeit von Heizwärme‐Bilanzverfahren. Einführung eines Heizperiodenbilanzverfahrens mit analytischen Klimafunktionen
Authors: Rabenstein Dietrich 
Published: June 2004

AbstractMit geglätteten harmonischen Verläufen der Außentemperatur und der Strahlungsintensitäten lassen sich Heizzeit, mittlere Außentemperatur und Globalstrahlung in der Heizperiode als Funktionen der Heizgrenztemperaturen angeben. Bei Vernachlässigung der zeitlichen Verschiebung zwischen Strahlungsintensitäten und Außentemperatur läßt sich auch die gemittelte Heizgrenztemperatur als einfache Funktion der Gebäudeparameter und der Klimagrößen darstellen. Vergleiche bei kleinen Wärmegewinnen zeigen, daß beim Monatsbilanzverfahren und noch ausgeprägter beim Heizperiodenbilanzverfahren nach EN 832 eine Tendenz zur Unterschätzung des Jahres‐Heizwärmebedarfs von Gebäuden besteht, die sich umso stärker auswirkt, je kleiner die Heizzeit ist. Bei kürzeren Heizzeiten als 4 Monaten pro Jahr steht sogar die Eignung des Monatsbilanzverfahrens als Referenzverfahren in Frage.Das analytische Bilanzverfahren, ein einfaches, vollständig analytisches Heizperiodenbilanzverfahren zur Berechnung des Heizwärmebedarfs für unterschiedliche energetische Standards wird vorgestellt. Die erreichbare Berechnungsgenauigkeit wurde durch Vergleiche mit dem Monatsbilanzverfahren nach DIN EN 832 und DIN V 4108‐6 ermittelt. Für längere Heizzeiten als 5 Monate pro Jahr weicht der nach diesem Verfahren berechnete Jahres‐Heizwärmebedarf bei den meisten praktisch vorkommenden Berechnungsfällen um weniger als 2 % vom entsprechenden Ergebnis des Monatsbilanzverfahrens ab.Das von Loga vorgeschlagene vereinfachte Heizperiodenbilanzverfahren für Gebäude mit unterschiedlichen energetischen Standards wird analysiert und mit dem analytischen Bilanzverfahren verglichen.
Perianal Crohn's disease
Authors: Singh B , McC Mortensen N J , Jewell D P , George B 
Published: June 2004

Abstract

Background
The management of perianal Crohn's disease is difficult. A wide variety of treatment options exist although few are evidence based.

Methods
A search was conducted using the National Library of Medicine for articles on perianal Crohn's disease and its incidence, classification, assessment and management.

Results and conclusion
Perianal Crohn's disease can manifest as skin tags, ulcers, fissures, abscesses, fistulas or stenoses. Improved radiological imaging with endoanal anal ultrasonography and magnetic resonance imaging has improved its assessment and may be used to predict outcome after surgery. Many treatment options exist. During acute complications they are generally aimed at resolving the immediate problem and limiting damage to anal and perianal tissues; this may be a ‘bridge’ to definitive treatment. The likelihood of success of definitive treatment must be weighed against the risk of complications, especially faecal incontinence.
Alternativen zu tierischen Proteinen: Schlüsselkomponenten der Nahrung
Authors: Doltsinis Stefanos , Andlauer Wilfried 
Published: June 2004

AbstractLebensmittel sind komplexe Systeme chemischer Stoffe. Ihre Minorbestandteile können Hürden bei der Bereitstellung essentieller Nährstoffe darstellen oder Förderer positiver metabolischer Mechanismen sein. Für die Bevölkerungen der verschiedenen Regionen der Welt sind unterschiedliche Produkte gefragt.
Elektronentransport in der DNA
Authors: Groß Michael 
Published: June 2004

AbstractDie DNA‐Doppelhelix ist seit einem halben Jahrhundert als Speicher der genetischen Information eine molekulare Berühmtheit. Weniger bekannt ist, dass sie seit gut einem Jahrzehnt auch als molekulares Kabel für den Transport elektrischer Ladungen dient. Ein wichtiger Grund für die Erforschung der Leitfähigkeit der Erbsubstanz besteht darin, dass der Stromfluss von der korrekten Basenpaarung abhängt und somit als hochsensibler Sensor für eine bestimmte Gensequenz dienen kann.
A study of digital instantaneous value control with filter capacitor current compensation for PWM inverter
Authors: Yokoyama Tomoki , Igarashi Yoshitaka , Haneyoshi Toshimasa , Izumi Tomonori 
Published: June 2004

AbstractA new approach for real‐time digital feedback control of PWM inverter is proposed, in which an instantaneous value control with filter capacitor current compensation is achieved. In this scheme, the sampling frequency of the inverter becomes half of the carrier frequency, and it is suitable to implement for higher carrier frequency.In this paper, the output characteristics of the inverter for various LC filter components are evaluated. From the viewpoint of UPS applications, the advantages and disadvantages are discussed through simulations and experiments, and the superiority of the proposed control law is verified. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(3): 72–79, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10329
Frontline: Epitope recognition on the myelin/oligodendrocyte glycoprotein differentially influences disease phenotype and antibody effector functions in autoimmune demyelination
Authors: von Büdingen Hans‐Christian , Hauser Stephen L. , Ouallet Jean‐Christophe , Tanuma Naoyuki , Menge Til , Genain Claude P. 
Published: June 2004

AbstractPreliminary observations of humoral immunity against the myelin oligodendrocyte glycoprotein (MOG) in experimental allergic encephalomyelitis (EAE) and human multiple sclerosis (MS) suggest that a subset of anti‐MOG autoantibodies directed against conformational epitopes is of pathogenic predominance. Here, we provide proof that in marmoset EAE, autoantibodies reactive against conformational epitopes of MOG are not only responsible for aggravating demyelination, but also an essential factor for disease dissemination in space within the central nervous system, a hallmark for typicalforms of human MS. In terms of effector mechanisms, IgG deposition and complement activation occur exclusively in association with presence of these conformational antibodies, while microglial/macrophage activation appears to be a common immunopathological finding regardless of the fine determinant specificity of anti‐MOG antibodies. These findings highlight for the first time the complex heterogeneity of function and pathogenicity in the polyclonal anti‐MOG antibody repertoire of outbred species. Because the linear and conformational antibody determinants of MOG are shared between marmosets and humans, these results are directly relevant to understanding effector mechanisms of organ damage in MS.See accompanying Commentary http//dx.doi.org/10.1002/eji.200425291
Mono‐ and Dinuclear High‐Spin Half‐Sandwich Manganese(II) Complexes Containing Acetylide and TMEDA Ligands
Authors: Kheradmandan Sohrab , Fox Thomas , Schmalle Helmut W. , Venkatesan Koushik , Berke Heinz 
Published: June 2004

AbstractThe d5 high‐spin MnII half‐sandwich complexes [Mn(C≡CR)(MeC5H4)(tmeda)] (R = SiMe3 2; Ph 3; tBu 4; C≡CSiMe3 5; C≡CPh 6; tmeda = N,N,N′,N′‐tetramethylethylenediamine) were prepared by the reaction of [Mn(MeC5H4)2(tmeda)] (1) with 1 equiv. of the corresponding acetylene or the trimethyltin acetylide. The dinuclear complexes [Mn(C≡C−C≡CSiMe3)2(tmeda)]2 (7) and [Mn2(MeCp)2(μ1‐tBuC≡C)2(μ1‐tmeda)] (8), which contain Mn−Mn bonds, were synthesized by treating 1 with an excess of HC≡C−C≡CSiMe3 or HC≡CtBu, respectively. Dinuclear complexes of the type [(MeC5H4)(tmeda)MnC≡C− X−C≡CMn(tmeda)(C5H4Me)] [X = 1,3‐C6H4 9; 1,4‐C6H4 10; 4,4′‐(C6H4)2 11] were obtained by treatment of 1 with 0.5 equiv. of the corresponding acetylides 1,3‐C6H4(C≡CSnMe3)2, 1,4‐C6H4(C≡CSnMe3)2 and 4,4′‐(C6H4)2(C≡CSnMe3)2 in benzene for 24 h to yield the corresponding dinuclear complexes in very good yields. All the mono‐ and dinuclear compounds have been characterized by NMR, IR, Raman spectroscopy and elemental analyses. X‐ray diffraction studies have been performed on complexes 3 and 5−11. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electron Transfer Behavior of Multi‐Iron Sandwich‐Type Polyoxometalates and Electrocatalytic Reduction Reactions
Authors: Keita Bineta , Mbomekalle Israel Martyr , Lu Yu Wei , Nadjo Louis , Berthet Patrick , Anderson Travis M. , Hill Craig L. 
Published: June 2004

AbstractThe physicochemical and electrocatalytic behaviors of eight multi‐iron Wells−Dawson sandwich‐type polyoxometalates were studied with specific emphasis on the FeIII centers. Magnetization measurements were used to identify and quantify the antiferromagnetic interactions between the edge‐sharing FeIII units. Electrochemical studies show the stepwise reduction of the FeIII centers, in complete agreement with magnetization conclusions. The location of the potential of each wave depends on the pH of the solution, as well as the concentration and composition of the electrolyte. In addition, ion‐pairing studies show there is a positive shift of the FeIII centers with an increase in ion pairing (i.e. K+ > Na+ > Li+). The electrocatalytic reduction of dioxygen and hydrogen peroxide is efficient for all the complexes. However, there is a pronounced increase in efficiency as the number of FeIII centers in the complex increases (i.e. 4 FeIII > 3 FeIII > 2 FeIII). The mixed‐metal complexes [αββα‐Na14(MnIIOH2)2(FeIII)2(As2W15O56)2 and αββα‐Na14(MnIIOH2)2(FeIII)2(P2W15O56)2] are also efficient catalysts for the reduction of NO and HNO2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Comparison of Hemoglobin and Myoglobin for In Situ Metabolite Generation in Chemical Toxicity Sensors Using a Metallopolymer Catalyst for DNA Damage Detection
Authors: Mugweru Amos , Yang Jing , Rusling James F. 
Published: June 2004

AbstractDetection of DNA damage can serve as the basis for rapid, inexpensive screening of the toxicity of new chemicals. Sensors for this purpose can be constructed on electrodes using layer‐by‐layer electrostatic adsorption of DNA and bioactivating proteins that mimic liver cytochrome P450s. This paper evaluates the use of the inexpensive protein hemoglobin (Hb) as the bioactivating “enzyme” in such sensors. Stable films containing myoglobin (Mb) and DNA, and Hb and DNA, were assembled one layer at a time on rough pyrolytic graphite (PG) electrodes on top of a 900 nm thick layer of chloro‐bis(bipyridyl)ruthenium(II)‐poly(vinylpyridine) [PVP‐ClRu(bpy)22+], a catalyst for DNA oxidation. The films showed independent, chemically reversible voltammetric peaks for protein heme FeIII/FeII and polymer RuIII/RuII redox sites. Incubation of PVP‐ClRu(bpy)22+‐(DNA/protein)3 films in pH 5.5 buffer containing styrene and hydrogen peroxide over 15 min resulted in nearly linear increases in catalytic square‐wave voltammetric (SWV) peaks at the RuII oxidation potential of ca. 0.73 V (vs. SCE). Films using Hb performed equally well as those containing Mb. No significant changes in SWV peaks were found for control incubations with toluene and hydrogen peroxide, styrene without hydrogen peroxide, or hydrogen peroxide alone.
Microemulsion electrokinetic chromatography of drugs varying in charge and hydrophobicity Part II: Strategies for optimization of separation
Authors: Harang Valérie , Jacobsson Sven P. , Westerlund Douglas 
Published: June 2004

AbstractThe separation of anionic, cationic, and neutral drugs in microemulsion electrokinetic chromatography (MEEKC) was studied. The concentration of sodium dodecyl sulfate (SDS; surfactant) and 2‐propanol (organic solvent) was varied in a three‐level full factorial design. 29 different model substances were chosen with different hydrophobicities and charges (neutral, positive, and negative). The models were calculated by means of multiple linear regression (MLR). The compounds were divided into five different subgroups, and different strategies for optimization of the separation within each group were investigated. The optimization was done by maximizing the selectivity using response surface plots in MODDE, by calculation of different chromatographic functions, and by using the software DryLab™. For all the different groups, MODDE, almost all chromatographic functions and DryLab™ gave approximately the same settings of the factors for optimum separation. Attempts were made to fit descriptors of the compounds to the retention data from the three‐level full factorial design by means of partial least squares projection to latent structures (PLS). Between 86 and 89% of all predictions of migration times were acceptable (80–120% of the observed value).