bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of a Hexagonal Nanosized Macrocyclic Fluorophore with Integrated Endotopic Terpyridine Metal‐Chelation Sites
Authors: Baxter Paul N. W. 
Published: October 2003

AbstractA rigid nanosized hexagonal phenylethynyl cyclophane 5 has been prepared, which incorporates two 2,2′:6′,2″‐terpyridines as integral structural units, for the purpose of binding metal ions. Macrocycle 5 was obtained by a 14‐step synthesis in an overall yield of 11 %, and was characterised by spectroscopic techniques. The efficiency and ease of all transformations, and the relatively enhanced yield of the final macrocyclisation suggests that the entire synthetic pathway should be amenable to scale‐up. Cyclophane 5 possesses four bulky triisopropylsilyl(TIPS)‐protected ethyne substituents which serve a dual role. Firstly, they solubilise the structure thereby facilitating purification and subsequent handling. Secondly, they enable post‐synthetic modification in which additional functionality may be attached to the periphery of the ring. Significantly, 5 was found to be a fluorescent chromophore, and may therefore potentially function as a new sensory platform for the detection of metal ions and H‐bond donating biological substrates. The structurally well‐defined nanosized morphology of 5, coupled with its interesting spectroscopic properties, supports the expectation that 5 and related architectures will attain a wealth of future applications within the developing fields of nanochemistry and nanoscience.
Stereoselective Aldol Additions Catalyzed by Dihydroxyacetone Phosphate‐Dependent Aldolases in Emulsion Systems: Preparation and Structural Characterization of Linear and Cyclic Iminopolyols from Aminoaldehydes
Authors: Espelt Laia , Parella Teodor , Bujons Jordi , Solans Conxita , Joglar Jesús , Delgado Antonio , Clapés Pere 
Published: October 2003

AbstractThe potential of dihydroxyacetone phosphate (DHAP)‐dependent aldolases to catalyze stereoselective aldol additions is, in many instances, limited by the solubility of the acceptor aldehyde in aqueous/co‐solvent mixtures. Herein, we demonstrate the efficiency of emulsion systems as reaction media for the class I fructose‐1,6‐bisphosphate aldolase (RAMA) and class II recombinant rhamnulose‐1‐phosphate aldolase from E. coli (RhuA)‐catalyzed aldol addition between DHAP and N‐benzyloxycarbonyl (N‐Cbz) aminoaldehydes. The use of emulsions improved the RAMA‐catalyzed aldol conversions by three to tenfold relative to those in conventional DMF/water mixtures. RhuA was more reactive than RAMA towards the N‐Cbz aminoaldehydes regardless of the reaction medium. With (S)‐ or (R)‐Cbz‐alaninal, RAMA exhibited preference for the R enantiomer, while RhuA had no enantiomeric discrimination. The linear N‐Cbz aminopolyols thus obtained were submitted to catalytic intramolecular reductive amination to afford the corresponding iminocyclitols. This reaction was diastereoselective in all cases examined; the face selectivity was controlled by the stereochemistry of the newly formed hydroxyl group originating from the aldehyde. Characterization of the resulting iminocyclitols allowed the assessment of the diastereoselectivity of the enzymatic aldol reactions with respect to the N‐protected aminoaldehyde. RAMA formed single diastereoisomers from N‐Cbz‐glycinal and from both enantiomers of N‐Cbz‐alaninal, while 14 % of the epimeric product was observed from N‐Cbz‐3‐aminopropanal. Diastereoselectivity from RhuA was lower than that observed from RAMA. Interestingly, a single diastereoisomer was formed from (S)‐Cbz‐alaninal, whereas only a 34 % diastereomeric excess was observed from its enantiomer (i.e., (R)‐Cbz‐alaninal).
Low frequency bursts and ionization instabilities in weakly ionized plasmas
Authors: Alcaide I. , Balam P.C. , Conde L. , Ionita C. , Schrittwieser R. 
Published: October 2003

AbstractIn this paper we report time dependent ion density bursts observed during the electron collection process from an unmagnetized plasma by a positively polarized electrode. For bias voltages over a threshold a double layer develops and the electron drained current exceeds the thermal levels. The energized electrons by the plasma potential voltage drop would excite a ionization instability in the plasma located at the high potential side, causing the subsequent fluctuations in the ion current downstream the double layer. These oscillations in the ion density were detected as abrupt decrements in the electron saturation current of a collecting Langmuir probe, located in Maxwellian background plasma, away form the double layer. The time elapsed between two successive jumps in ion density decreases with the amount of current drained by the metallic electrode. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Alcohol intake in social housing and in isolation before puberty and its effects on voluntary alcohol consumption in adulthood
Authors: Juárez Jorge , Vázquez‐Cortés Cristina 
Published: October 2003

AbstractWe assessed the effects of alcohol exposure in social and isolation housing before puberty on the alcohol consumption later in adulthood. From 25 to 35 days of age, Wistar male rats were exposed to either (a) continuous isolation; (b) continuous social housing; (c) continuous isolation, but placed in social housing during 12 hr every other day; or (d) continuous social housing, but placed in isolation during 12 hr every other day (SOIS group). All males were exposed to 8% ethanol as the only available liquid 12 hr/day every other day in this prepubescent period and to continuous free‐choice access to 8% ethanol or water in both social and isolation housing when adulthood was reached. Alcohol consumption before puberty was higher in the group permanently housed in isolation. Both voluntary alcohol intake and preference for alcohol in adulthood also were higher during the isolation than in the social condition in all groups, except in the SOIS group. Alcohol consumption was higher in the SOIS group than in the other groups only during social condition in adulthood. Food intake decreased during the social interaction of the groups that changed their condition from isolated to social or from social to isolated. Results support that (a) isolation facilitates alcohol consumption, and (b) rearing characteristics associated to alcohol intake at an early age can play an important role in later alcohol intake. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 200–207, 2003.
Short‐term stability of physiological measures in kindergarten children: Respiratory sinus arrhythmia, heart period, and cortisol
Authors: Doussard‐Roosevelt Jane A. , Montgomery Lee Anne , Porges Stephen W. 
Published: October 2003

AbstractThe short‐term stability of measures of respiratory sinus arrhythmia (RSA), heart period, and salivary cortisol and the relation of these variables to one another and to measures of social competence in kindergartners were examined. Physiological measures were collected during multiple individual sessions with 30 kindergarten children, ages 5 to 6 years. Three sessions were scheduled at 2‐week intervals and included a negative affect task as a challenge. Cardiovascular and cortisol responses to the challenge were assessed. Results indicated that baseline measures of RSA and heart period were stable across time. Baseline cortisol levels were not stable. The change in RSA in response to a task that elicited emotional responses was not stable over time. Consistent with findings observed in adults and older children, changes in RSA were related to the cortisol response. Children who increased cortisol over the course of Session 1 exhibited larger decreases in RSA than children who did not show increased cortisol levels. In addition, the children who had larger decreases in RSA had higher ratings of sociability on the Colorado Childhood Temperament Inventory. Greater decreases in heart period during the task were associated with lower ratings of shyness. The relation of RSA measures to ratings of social competence supports the Polyvagal Theory (Porges, 1995, 2001), which suggests that the ability to engage and disengage with objects and people in one's environment, necessary for social competence, is related to the regulation of vagal control of the heart. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 230–242, 2003.
Operation and economy of a refuse‐fired generating system with electricity wheeling service
Authors: Kemmoku Yoshishige , Fujiwara Yoshikazu , Takikawa Hirofumi , Sakakibara Tateki 
Published: October 2003

AbstractElectric power markets have been partially liberalized and liberalization will be proceeding steadily. On the other hand, refuse‐fired generating systems (RGS) are constructed in many municipal corporations as on‐site power sources. This paper discusses the operation of an RGS which can transfer its excess energy to consumers through the electricity wheeling service of the electric utility. The RGS is operated by the dynamic programming method under the constraints of RGS operation and electricity wheeling service. In the DP method, the estimation function is the annual total electricity charge of both the RGS and the consumers, and the control variable is the residual amount in the refuse pit. A university, hospitals, welfare apartment houses, and their combinations are selected as consumers. The main results obtained are as follows: (1) electricity wheeling service is more economical than the absence of electricity wheeling service when the annual demand of the consumer is higher than 70% of the excess energy of RGS; (2) it is more economical as the load factor increases if the annual demand is the same; (3) the most economical consumer is the combination of four hospitals and five welfare apartment houses, for which the total electricity charge can be reduced to 84% of that in the absence of wheeling service. It is concluded that the total electricity charge of the RGS with electricity wheeling service could be decreased considerably by selecting the consumers appropriately. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 59–69, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10211
Transient response of a grounding system in an underground GIS substation
Authors: Okabe Shigemitsu , Yamada Michio , Nojima Kenichi , Suzuki Katsumi 
Published: October 2003

AbstractThe transient grounding impedance of a gas‐insulated switchgear (GIS) substation was investigated through measurements on a commercial 300‐kV underground substation. Using the results, the transient impedance of the grounding grid was investigated. The attenuation factor of the propagation line composed of the outer surface of the GIS tank and the concrete floor was also evaluated. The validity of EMTP analysis of surge phenomena in the GIS grounding system was confirmed. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 70–77, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10214
Feasible enhancement of a three‐phase soft‐switching inverter with an auxiliary resonant DC link snubber
Authors: Kurokawa Manabu , Konishi Yoshihiro , Nakaoka Mutsuo 
Published: October 2003

AbstractThe purpose of this paper is to improve power conversion efficiency of a three‐phase voltage source type soft‐switching inverter with a single auxiliary resonant DC link (ARDCL) snubber. First, the operating principle of an ARDCL snubber discussed here is described. Second, this paper proposes an effective pulse pattern generation method of the zero voltage space vector of the three‐phase soft‐switching inverter using IGBTs or power modules that can reduce power losses in the ARDCL snubber treated here. In particular, a zero voltage holding interval in the DC rail busline of this three‐phase soft‐switching inverter is to be regulated according to the generation method of the zero voltage space vector. Third, the maximum modulation depth Mmax under the condition of correction of the instantaneous voltage space vector can be improved by using a new zero voltage space vector generation method. Finally, the feasible experimental results of this inverter are obtained confirming the operating characteristics such as power conversion actual efficiency, as well as conventional efficiency THD and RMS value of the balanced three‐phase output voltage for an experimentally built three‐phase voltage source type soft‐switching pulse modulated inverter using the latest IGBT modules and evaluated from the standpoint of practical applications in industry UPS and new energy systems. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 89–99, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10234
Influence of wave front steepness and accumulated charge on creeping discharge
Authors: Ueno Hideki , Nakayama Hiroshi 
Published: October 2003

AbstractThe creeping flashover voltage–time characteristics for the composite insulating configuration by insertion of a barrier between a needle electrode and a plane electrode in N2 gas have been investigated. A maximum creeping flashover voltage of around 10 µs has been found in N2 gas for negative polarity. This anomalous voltage–time characteristic is associated with the low field relaxation effect of the accumulated charges on the barrier for an applied pulse voltage with a highly steep wave front. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 1–8, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10249
Logistic regression of family data from retrospective study designs
Authors: Whittemore Alice S. , Halpern Jerry 
Published: October 2003

AbstractWe wish to study the effects of genetic and environmental factors on disease risk, using data from families ascertained because they contain multiple cases of the disease. To do so, we must account for the way participants were ascertained, and for within‐family correlations in both disease occurrences and covariates. We model the joint probability distribution of the covariates of ascertained family members, given family disease occurrence and pedigree structure. We describe two such covariate models: the random effects model and the marginal model. Both models assume a logistic form for the distribution of one person's covariates that involves a vector β of regression parameters. The components of β in the two models have different interpretations, and they differ in magnitude when the covariates are correlated within families. We describe ascertainment assumptions needed to estimate consistently the parameters βRE in the random effects model and the parameters βM in the marginal model. Under the ascertainment assumptions for the random effects model, we show that conditional logistic regression (CLR) of matched family data gives a consistent estimate ${\hat{\beta }}_{RE} $ for βRE and a consistent estimate for the covariance matrix of ${\hat{\beta }}_{RE} $. Under the ascertainment assumptions for the marginal model, we show that unconditional logistic regression (ULR) gives a consistent estimate for βM, and we give a consistent estimator for its covariance matrix. The random effects/CLR approach is simple to use and to interpret, but it can use data only from families containing both affected and unaffected members. The marginal/ULR approach uses data from all individuals, but its variance estimates require special computations. A C program to compute these variance estimates is available at http://www.stanford.edu/dept/HRP/epidemiology. We illustrate these pros and cons by application to data on the effects of parity on ovarian cancer risk in mother/daughter pairs, and use simulations to study the performance of the estimates. Genet Epidemiol 25:177–189, 2003. © 2003 Wiley‐Liss, Inc.
Elasto‐hydrodynamische Simulationstechnik mit integriertem Mischreibungskontakt
Authors: Knoll G. 
Published: October 2003

AbstractMit den Entwicklungszielen neuer Konzepte in der Motoren‐ und Antriebstechnik verbunden ist die Forderung nach immer höherer spezifischer Leistungsdichte. Die sichere Auslegung der Lagerungen erfordert hierbei ein besseres Systemverständnis für Wechselwirkungen, die sich aus tribologischer und konstruktiver Sicht ergeben. Ein Weg zum besseren Systemverständnis ist die Simulationstechnik auf Basis hochauflösender Modelle. Zur Verbesserung der Auslegungssicherheit sowie zur Ausnutzung bisher ungenutzter werkstoff‐ und schmierungstechnischer sowie konstruktiver Optimierungspotentiale wird in der Gleitlagertechnik intensiv an der Entwicklung von Simulationsverfahren gearbeitet, welche – gegenüber den bisherigen Auslegungsverfahren – auch Parameter berücksichtigen, welche für den Übergang und die Intensität von Mischreibungszuständen maßgeblich sind. Aus fluid‐mechanischer Sicht bestimmt die Oberflächenfeingestalt maßgeblich die tribologischen Eigenschaften hinsichtlich der mikrohydrodynamischen Schmierfilmbildung und der mechanischen Beanspruchung im Festkörperkontakt. In dem vorliegenden Beitrag werden Verfahren zur tribologischen Kennwertbildung rauer Oberflächen durch Flusstensoren und durch Kontaktdruckkennfelder sowie deren Integration in elasto‐hydrodynamische Berechnungstechniken vorgestellt. Hieraus abgeleitet wird ein örtliches Konzept zur Ermittlung qualitativer und quantitativer Verschleißzustände. Zur Ermittlung der notwendigen werkstoffspezifischen Kenndaten wurden außermotorische Gleitlagerversuche für unterschiedliche Lager‐ und Wellenwerkstoffe durchgeführt.
Synergistic effects of RAD and Neoral in inhibition of host‐vs.‐graft and graft‐vs.‐host immune responses in rat small‐bowel transplantation
Authors: Johnson Stéphane , Qi Shiji , Xu Dasheng , Jolicoeur Marc , Liu Dingyi , Barama Azemi , Busque Stéphane , Smeesters Christian , Daloze Pierre , Chen Huifang 
Published: October 2003

AbstractThe combined effects of RAD and Neoral were tested in a rat orthotopic small‐bowel transplantation model. Seven groups (n = 6) were involved in this study, and each one was included in three rejection models for the evaluation of host‐vs.‐graft disease (HVG) (LBN‐F1 to LEW), graft‐vs.‐host disease (GVH) (LEW to LBN‐F1), and combined HVG and GVH immune responses (BN to LEW). Both drugs were administered orally throughout the study. Low doses of RAD (1.0–2.5 mg/kg/day) combined with Neoral (2.0–5.0 mg/kg/day) produced strong synergistic effects in the prolongation of small‐bowel graft survival in HVG (combination index, CI = 0.095, 0.1212), GVH (CI = 0.027, 0.020), and combined HVG and GVH immune responses (CI = 0.070, 0.301). The combination therapy of RAD and Neoral produces a strong synergistic effect toward the inhibition of HVG, GVH, and combined HVG and GVH immune responses in a rat small‐bowel transplantation model. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:476–482 2003
Observations of rat ovarian‐splenic consecutive transplants
Authors: Hong I.C. , Lee S. , Yoo C.H. , Nam S. , Bai S. , Kim K. , Pivetti C.D. , Niewiadomski S.T. , Wolf P. , Gittes R.F. 
Published: October 2003

AbstractWe examined the results after implantation of ovarian follicles by various modes in a total of 82 cases. One or five ovarian follicles were implanted into spleens in castrated female rats. In 20 cases among these, each five follicles were implanted into native and transplanted spleens after spleen transplantation (double implantation of the ovary). Through consecutive spleen transplantation, we observed the results beyond the rat's life span for a limited period. In many cases, we found a more aggressive form of malignant tumor, i.e., dysgerminoma. We present the results and discuss the modes of implantations and possible pathogenetic mechanisms of tumor formation. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:450–453 2003
Effect of annealing on the electrical properties and morphology of a conducting polymer used as an anode in organic light‐emitting devices
Authors: Kim W. H. , Kushto G. P. , Kim H. , Kafafi Z. H. 
Published: October 2003

AbstractThe surface sheet resistance of conducting films of glycerol‐doped poly(3,4‐ethylenedioxy‐thiophene)–poly(styrene sulfonate) is largely dependent on the annealing temperature. The presence of free glycerol in insufficiently baked films, as indicated by infrared spectra and thermogravimetric analysis, results in conducting polymer films with poor morphology and low electrical conductivity. The device performance of organic light‐emitting diodes using this modified poly(3,4‐ethylenedioxy‐thiophene)–poly(styrene sulfonate) as an anode is also greatly affected by the baking conditions of the conducting films. The maximum light output, current density, and luminous power efficiency are observed from devices using anodes baked at a high temperature close to the boiling point of glycerol. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2522–2528, 2003
New materials for optical rectification and electrooptic sampling of ultrashort pulses in the terahertz regime
Authors: Hayden L. Michael , Sinyukov Alexander M. , Leahy Megan R. , French Joey , Lindahl Peter , Herman Warren N. , Twieg Robert J. , He Meng 
Published: October 2003

AbstractThe synthesis and nonlinear optical characterization of new electrooptic (EO) materials useful for terahertz (THz) applications is presented. Semiempirical calculations were used to guide the development of a series of chromophores on the basis of 2‐dicyanomethylen‐3‐cyano‐4,5,5‐trimethyl‐2,5‐dihydrofuran acceptors acting as guests in polymer films used in the generation of THz radiation via optical rectification. Amorphous films, 65–250 μm thick, with EO coefficients as high as 52 pm/V at 785 nm were used to generate sub‐picosecond pulses with bandwidths up to 3 THz. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2492–2500, 2003
Field effect conductance of conducting polymer nanofibers
Authors: Merlo Jeffrey A. , Frisbie C. Daniel 
Published: October 2003

AbstractWe report on the electrical conductance of nanofibers of regioregular poly(3‐hexylthiophene) (RRP3HT) as a function of gate‐induced charge. Nanofibers of RRP3HT were deposited onto SiO2/Si substrates by casting from dilute p‐xylene solutions. An analysis of the nanofibers by atomic force microscopy revealed fiber lengths of 0.2–5 μm, heights of 3–7 nm, and widths of approximately 15 nm. A field effect transistor geometry was used to probe the conductance of webs of nanofibers and single nanofibers; in these measurements, gold electrodes served as source and drain contacts, and the doped SiO2/Si substrate served as the gate. Temperature‐dependent transport studies on webs of nanofibers revealed an activation energy of 108 meV at a gate‐induced hole density of 3.8 × 1012 charges/cm2. Pretreating SiO2 with a hydrophobic hexamethyldisilazane (HMDS) layer reduced the activation energy to 65 meV at the same charge density. The turn‐on gate voltage on treated and untreated substrates increased in magnitude with decreasing temperature. Conductance measurements on single nanofibers on HMDS‐treated SiO2 yielded hole mobilities as high as 0.06 cm2/Vs with on/off current ratios greater than 103. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2674–2680, 2003