bluuebunny/crossref_metadata_2025_split huggingface dataset:
Desorption kinetics of model polar stratospheric cloud films measured using Fourier Transform Infrared Spectroscopy and Temperature‐Programmed Desorption
Authors: Koehler Birgit G. 
Published: September 2002

AbstractThis study combines Fourier transform infrared (FTIR) spectroscopy and temperature‐programmed desorption to examine the evaporation kinetics of thin films of crystalline nitric acid hydrates, solid amorphous H2O/HNO3 mixtures, H2O–ice, ice coated with HCl, and solid HNO3. IR spectroscopy measured the thickness of each film as it evaporated, either at constant temperature or during a linear temperature ramp (temperature‐programmed infrared, TPIR). Simultaneously, a mass spectrometer measured the rate of evaporation directly by monitoring the evolution of the molecules into the gas phase (temperature‐programmed desorption, TPD). Both TPIR and TPD data provide a measurement of the desorption rate and yield the activation energy and preexponential factor for desorption. TPD measurements have the advantage of producing many data points but are subject to interference from experimental difficulties such as uneven heating from the edge of a sample and sample‐support as well as pumping‐speed limitations. TPIR experiments give clean but fewer data points. Evaporation occurred between 170 and 215 K for the various films. Ice evaporates with an activation energy of 12.9 ± 1 kcal/mol and a preexponential factor of 1 × 1032±1.5 molec/cm2 s, in good agreement with the literature. The beta form of nitric acid trihydrate, β–NAT, has an Edes of 15.6 ± 2 kcal/mol with log A = 34.3 ± 2.3; the alpha form of nitric acid trihydrate, α–NAT, is around 17.7 ± 3 kcal/mol with log A = 37.2 ± 4. For nitric acid dihydrate, NAD, Edes is 17.3 ± 2 kcal/mol with log A = 35.9 ± 2.6; for nitric acid monohydrate, NAM, Edes is 13 ± 3 kcal/mol with log A = 31.4 ± 3. The α–NAT converts to β–NAT during evaporation, and the amorphous solid H2O/HNO3 mixtures crystallize during evaporation. The barrier to evaporation for pure nitric acid is 14.6 ± 3 kcal/mol with log A = 34.4 ± 3. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 295–309, 2001
Kinetics of OH reactions with N2H4, CH3NHNH2and (CH3)2NNH2in the gas phase
Authors: Vaghjiani Ghanshyam L. 
Published: September 2002

AbstractThe gas phase reaction kinetics of OH with three di‐amine rocket fuels—N2H4, CH3NHNH2, and (CH3)2NNH2—was studied in a discharge flow tube apparatus and a pulsed photolysis reactor under pseudo‐first‐order conditions in [OH]. Direct laser‐induced fluorescence monitoring of the [OH] temporal profiles in a known excess of the [diamine] yielded the following absolute second‐order OH rate coefficient expressions;k1= (2.17 ± 0.39) × 10−11e(160±30)/T,k2= (4.59 ± 0.83) × 10−11e(85±35)/Tandk3= (3.35 ± 0.60) × 10−11e(175±25)/Tcm3molec−1s−1, respectively, for reactions with N2H4, CH3NHNH2and (CH3)2NNH2in the temperature range 232–637 K. All three reactions did not show any discernable pressure dependence on He or N2buffer gas pressure of up to 530 torr. The magnitude of the weak temperature and the lack of pressure effects of the OH + N2H4reaction rate coefficient suggest that a simple direct metathesis of H‐atom may not be important compared to addition of the OH to one of the N‐centers of the diamine skeleton, followed by rapid dissociation of the intermediate into products. Our findings on this reaction are qualitatively consistent with a previousab initiostudy [3]. However, in the alkylated diamines, direct H‐abstraction from the methyl moiety cannot be completely ruled out. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 354–362, 2001
Oxidation of 3‐(3,4‐dihydroxy phenyl)‐l‐alanine (levodopa) and 3‐(3,4‐dihydroxy phenyl)‐2‐methyl‐l‐alanine (methyl dopa) by manganese(III) in pyrophosphate media: Kinetic and mechanistic study
Authors: Sherigara B. S. , Kumara Swamy B. E. , Subrahmanyam E. V. S. , Ishwar Bhat K. 
Published: September 2002

AbstractManganese(III) (Mn(III)) has been stabilized in weakly acidic solution by means of pyrophosphate and the nature of the complex was elucidated spectrophotometrically. Stoichiometry of Mn(III)‐oxidation of levodopa and methyl dopa in pyrophosphate medium was established in the pH range 2.5–4.0 by iodometric and spectrophotometric methods. The reaction shows a distinct variation in kinetic order with respect to [Mn(III)], a first‐order dependence in the pH range 1.9–2.6, decreasing to fractional order above pH 3. Other common features include first‐order dependence on [dopa], positive fractional order dependence on [H+], and inverse first‐order dependence on [Mn(III)] in the pH range studied. The effects of varying ionic strength and solvent composition were studied. Added ions such as SO42− and ClO4− alter the reaction rate, probably due to the change in the formal redox potential of Mn(III)–Mn(II) couple because of the changes in coordination environment of the oxidizing species. Evidence for the transient existence of the free radical intermediate is given. Cyclic voltametric sensing of levodopa and methyl dopa has ruled out the formation of dopaquinones as oxidation products in the pH range studied. Activation parameters have been evaluated using the Arrhenius and Erying plots. Mechanisms consistent with the kinetic data have been proposed and discussed. These studies are expected to throw some light on dopa metabolism. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 449–457, 2001
Comparative analysis ofrasproto‐oncogene mutations in selected mammalian tumors
Authors: Watzinger F. , Mayr B. , Gamerith R. , Vetter C. , Lion T. 
Published: September 2002

AbstractPoint mutations withinrasproto‐oncogenes are frequently detected in human malignancies and in different types of experimentally induced tumors in animals. In contrast to findings in experimental animal models of carcinogenesis, little is known about the incidence ofrasmutations in naturally occurring animal tumors. In the present study, we investigated whether point mutations, particularly within the mutational hot‐spot codons 12, 13, and 61, occur at comparable frequencies in human malignancies and spontaneously occurring tumors in other mammalian species. Two hundred seventy‐nine of the most frequent canine and feline neoplasms were analyzed for changes in mutational hot‐spot regions of the N‐, Ki‐, and Ha‐rasgenes. DNA fragments from exons 1 and 2 of all threerasgenes were amplified by polymerase chain reaction, and the presence of point mutations was assessed by single‐strand conformation polymorphism analysis and direct sequencing of amplified products. Only one sample, a case of canine melanoma, exhibited an Ha‐rasmutation. Thus, our data strongly suggested thatrasmutations at the hot‐spot loci are apparently very rare and do not play a major role in the pathogenesis of the spontaneously occurring canine and feline tumors investigated. These observations were in marked contrast to those in experimental rodent models of carcinogen‐induced mammary and skin tumors that described a consistent association with Ha‐ or Ki‐rasactivation. The role of ras oncogene activation in related human malignancies therefore cannot be readily inferred from studies of experimental carcinogenesis in animal models. © 2001 Wiley‐Liss, Inc.
Use of an arterialized venous flap for resurfacing a circumferential soft tissue defect of a digit
Authors: Chia John , Lim Aymeric , Peng Yeong‐Pin 
Published: September 2002

AbstractCircumferential defects of digit are uncommon but present a challenging problem to the clinician. The use of simple skin grafts tends to cause tendon adhesions and can limit digital range of motion. The use of local skin flaps, such as a cross‐finger flap, is limited by the considerable skin loss in a defect that is circumferential in nature. Other options have included the use of reversed forearm flap or some free tissue transfer. We report a case in which the circumferential defect of an index finger, measuring 6 cm around the digit and 3 cm long, is resurfaced by the use of a free arterialized venous flap raised from the volar forearm skin. © 2001 Wiley‐Liss, Inc. MICROSURGERY 21:374‐378; 2001
Vascular complication in free tissue transfer to the leg
Authors: Muramatsu Keiichi , Shigetomi Mitsunori , Ihara Koichiro , Kawai Shinya , Doi Kazuteru 
Published: September 2002

AbstractThe lower‐extremity free flap has a high incidence of vascular complication. A retrospective study of 70 free flap transplants in 70 patients (1987–2000) was conducted to investigate factors leading to vascular complication and free flap failure. The overall success rate was 92% (64 of 70 flaps); the incidence of vascular complications was 22% (16 of 70 flaps). Among 16 complicated flaps, 7 were transferred in severely crushed legs, and 4 were in multioperated legs attributable to chronic osteomyelitis. Venous thrombosis occurred in 12 flaps (86%). The success rate of the patients operated on at Yamaguchi University Hospital was higher (96%) than at other hospitals tested. The key factors contributing to improved outcome in free tissue transplantation in the leg were careful preoperative planning for highly traumatized legs and proper selection of the recipient vein and of the hospital at which immediate reexploration can be performed for vascular complicated flaps. © 2001 Wiley‐Liss, Inc. MICROSURGERY 21:362–365 2001
On the diffraction of Poincaré waves
Authors: Martin P. A. 
Published: September 2002

AbstractThe diffraction of tidal waves (Poincaré waves) by islands and barriers on water of constant finite depth is governed by the two‐dimensional Helmholtz equation. One effect of the Earth's rotation is to complicate the boundary condition on rigid boundaries: a linear combination of the normal and tangential derivatives is prescribed. (This would be an oblique derivative if the coefficients were real.) Corresponding boundary‐value problems are treated here using layer potentials, generalizing the usual approach for the standard exterior boundary‐value problems of acoustics. Singular integral equations are obtained for islands (scatterers with non‐empty interiors) whereas hypersingular integral equations are obtained for thin barriers. Copyright © 2001 John Wiley & Sons, Ltd.
Highly efficient L‐band EDFA for DWDM systems employing a self‐generated seed signal
Authors: Mahdi M. A. , Ahmad H. 
Published: September 2002

AbstractA novel method of a gain‐enhanced long‐wavelength band (L‐band) erbium‐doped fiber amplifier is presented utilizing a gain‐clamped amplifier based on a ring‐laser feedback. The laser output is used as a seed signal into a second‐stage arnplifier, and has improved the L‐band gain for higher dense wavelength‐division multiplexed channels. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 234–236, 2001.
Improved technique of H‐plane nonreciprocal ferrite phase shifter
Authors: Che Wenquan , Yung E. K. N. , Ma Jinping 
Published: September 2002

AbstractAn improved technique for an H‐plane nonreciprocal ferrite phase shifter is introduced in this letter. A numerical analysis is carried out using the finite‐element method (FEM) to determine the effect of the technique quantitatively. Both experimental and numerical results show that the differential phase shift of the improved device has been increased by over 70%. The measured results also show that the insertion loss of the improved device is smoother than that of the old one. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 236–237, 2001.
Estimating the RF attenuation rate via roadside trees with extraction techniques
Authors: Liu Ji‐Chyun , Wei Chia Ping , Chang Dau‐Chyrh , Chang Chung‐Chi , Cheng Ching 
Published: September 2002

AbstractModelings of the radio propagation channel are among the most important and fundamental issues. The levels of the desired signal and cochannel interference are associated with the measurement system. A new approach to estimate the RF attenuation rate (AR, dBm/m) with the extraction technique is introduced in this paper. Any changes due to an environmental disturbance or cochannel interference will cancel. The AR can be used to characterize the trees (or medium) with a linear expression. In practice, the attenuation rate results of four roadside trees are described based on data acquired from experiments employing an RF channel sounding system at 1800 MHz. It makes the estimations suitable for wireless communication systems. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 242–246, 2001.
Design of a wideband microstrip array antenna for PCS and IMT‐2000 service
Authors: Kim Taewoo , Choi Jaehoon , Jeon Joo Seong 
Published: September 2002

AbstractIn this letter, a wideband microstrip array antenna for a PCS and IMT‐2000 base station is designed. To obtain the wideband characteristic, we utilized a multilayered structure composed of foam materials and a parasitic element with an aperture‐coupled feeding network. The return‐loss characteristic is improved by placing the gaps between coupling slots. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 261–265, 2001.
Application of ferromagnetic composite in different planar tunable microwave devices
Authors: Salahun E. , Tanné G. , Quéffélec P. , Lefloc'h M. , Adenot A.‐L. , Acher O. 
Published: September 2002

AbstractIn this paper, several microwave devices using a ferromagnetic composite demonstrate great tunability under weak magnetizing field conditions. Indeed, a tunable bandstop of 50% tunability and phase shifters of 35°/dB figure of merit around 3 GHz and 7.8°/dB in the X‐band are obtained when a 250 Oe dc magnetic field is applied. Moreover, a magnetic switch near 25 dB isolation and less than 1 dB insertion losses is realized. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 272–276, 2001.
A dual‐band rectangular microstrip antenna using a novel photonic bandgap ground plane of unequal orthogonal periods
Authors: Kuo Yen‐Liang , Chiou Tzung‐Wern , Wong Kin‐Lu 
Published: September 2002

AbstractThis paper presents a novel photonic bandgap (PBG) structure of unequal orthogonal periods and its application to a dual‐band rectangular microstrip antenna for performance enhancement. The two operating frequencies of the dual‐band microstrip antenna studied have orthogonal polarization planes, and by using the proposed PBG ground plane with its periods in orthogonal directions determined from the two separate operating frequencies, gain enhancements of 1.7 and 1.1 dBi have been obtained for the lower and upper operating frequencies, respectively. Details of the PBG structure studied are described, and the obtained experimental results are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 280–283, 2001.
Decidualization and implantation: Embryo‐uterine bioinformatics at work
Authors: Kierszenbaum Abraham L. 
Published: September 2002

AbstractThe implantation of the blastocyst into a nurturing endometrium involves two overlapping steps: 1. The blastocyst‐endometrial luminal epithelial attachment. 2. The decidualization of the endometrial stroma. An intriguing question is how does the blastocyst identify the uterine implantation site. Current research is focused on hypothetical soluble signaling molecules released by the blastocyst for conditioning a discrete uterine luminal epithelial domain for implantation. A still unresolved issue is the functional significance of receptor autophosphorylation following binding of uterine epithelial cell‐derived heparin‐binding epidermal growth factor‐like growth factor to the epidermal growth factor receptor on trophoectodermic cell surfaces. With recent results hinting at the role of signaling proteins associated with the bone morphogenetic protein, fibroblast growth factor, WNT and hedgehog families to enable embryo implantation, the dynamics of uterine‐embryo interaction becomes linked to fundamental cellular pathways of growth, differentiation and apoptosis. Mol. Reprod. Dev. 59:123–125, 2001. © 2001 Wiley‐Liss, Inc.
Extracellular apparent diffusion in rat brain
Authors: Duong Timothy Q. , Sehy Jonathan V. , Yablonskiy Dmitriy A. , Snider B. Joy , Ackerman Joseph J.H. , Neil Jeffrey J. 
Published: September 2002

AbstractThe apparent diffusion coefficients (ADCs) of a series of markers concentrated in the extracellular space of normal rat brain were measured to evaluate, by inference, the ADC of water in the extracellular space. The markers (mannitol, phenylphosphonate, and polyethylene glycols) are defined as “compartment selective” because tissue culture experiments demonstrate some leakage into the intracellular space, making them less “compartment specific” than commonly believed. These primarily extracellular markers have ADCs similar to those of intracellular metabolites of comparable hydrodynamic radius, suggesting that water ADC values in the intra‐ and extracellular spaces are similar. If this is the case, then it is unlikely that a net shift of water from the extra‐ to the intracellular space contributes significantly to the reduction in water ADC detected following brain injury. Rather, this reduction is more likely due primarily to a reduction of the ADC of intracellular water associated with injury. Magn Reson Med 45:801–810, 2001. © 2001 Wiley‐Liss, Inc.
Region and tissue differences of metabolites in normally aged brain using multislice 1H magnetic resonance spectroscopic imaging
Authors: Schuff Norbert , Ezekiel Frank , Gamst Anthony C. , Amend Diane L. , Capizzano Andres A. , Maudsley Andrew A. , Weiner M.W. 
Published: September 2002

AbstractQuantitative measurements of regional and tissue specific concentrations of brain metabolites were measured in elderly subjects using multislice proton magnetic resonance spectroscopic imaging (1H MRSI). Selective k‐space extrapolation and an inversion‐recovery sequence were used to minimize lipid contamination and linear regression was used to account for partial volume problems. The technique was applied to measure the concentrations of N‐acetyl aspartate (NAA), and creatine (Cr)‐ and choline (Cho)‐containing compounds in cortical gray and white matter, and white matter lesions of the frontal and the parietal lobe in 40 normal elderly subjects (22 females and 18 males, 56–89 years old, mean age 74 ± 8). NAA was about 15% lower in cortical gray matter and 23% lower in white matter lesions when compared to normal white matter. Cr was 11% higher in cortical gray matter than in white matter, and also about 15% higher in the parietal cortex than in the frontal cortex. Cho was 28% lower in cortical gray matter than in white matter. Furthermore, NAA and Cr changes correlated with age. In conclusion, regional and tissue differences of brain metabolites must be considered in addition to age‐related changes when interpreting 1H MRSI data. Magn Reson Med 45:899–907, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of age, body mass index, and wrist index as risk factors for carpal tunnel syndrome severity
Authors: Kouyoumdjian Joao A. , Zanetta Dirce M.T. , Morita Maria P.A. 
Published: September 2002

AbstractTo determine the role of personal variables as risk factors for carpal tunnel syndrome (CTS) and their relationship to severity of nerve conduction abnormality, we studied 210 consecutive symptomatic CTS patients and 320 controls subjects without CTS symptomatology or known systemic disorders. The CTS group was classified according to the severity of nerve conduction changes. The risk factors for CTS and its severity were assessed by means of univariate and multivariate analysis. Presence of CTS was significantly related to increase of body mass index (BMI) and wrist index. More severe nerve conduction abnormalities were associated with greater age and wrist index but not with higher BMI. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 93–97, 2002
Proposed revised electrophysiological criteria for chronic inflammatory demyelinating polyradiculoneuropathy
Authors: Nicolas Guillaume , Maisonobe Thierry , Le Forestier Nadine , Léger Jean‐Marc , Bouche Pierre 
Published: September 2002

AbstractElectrophysiological criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) were proposed by an Ad Hoc Subcommittee of the American Academy of Neurology (AAN) in 1991. Only 60% of CIDP patients fulfilled these criteria, which therefore appear poorly sensitive. We therefore sought to revise the electrophysiological criteria. We selected 40 CIDP patients and compared them with 35 patients with axonal polyneuropathy, 116 patients with Charcot‐Marie‐Tooth type 1A (CMT1A) disease, and 66 patients with immunoglobulin M (IgM) monoclonal gammopathy. The proposed electrophysiological criteria identified 90% of the CIDP patients, although 3% of patients with axonal polyneuropathy were falsely identified. For the CIDP patients, sensitivity and specificity were 90% and 97%, respectively. Of the patients with IgM monoclonal gammaglobulin of undetermined significance (MGUS) and CMT1A, 100% fulfilled these new criteria, whereas 90% and 97%, respectively, fulfilled the AAN criteria. These results suggest that the AAN criteria are more appropriate for IgM MGUS and CMT1A patients than for CIDP patients. We therefore propose new electrophysiological criteria for CIDP that appear to have better sensitivity. © 2002 American Association of Electrodiagnostic Medicine Muscle Nerve 25: 26–30, 2002
Analysis of ephrin‐A2 in the chick retinotectal projection using a function‐blocking monoclonal antibody
Authors: Yamada T. , Okafuji T. , Ohta K. , Handwerker C. , Drescher U. , Tanaka H. 
Published: September 2002

AbstractEph receptor tyrosine kinases and their ligands have been shown to be involved in processes of cell migration and axon guidance during embryonic development. Here we describe the development of a function‐blocking monoclonal antibody against chick ephrin‐A2, and its effect on retinal ganglion cell axons studied both in vitro and in vivo. In the stripe assay, the blocking antibody completely abolished the repulsive effect of posterior tectal membranes. In vivo, in a loss‐of‐function approach, hybridoma cells secreting the antiephrin‐A2 antibody were applied to chick embryos from embryonic day 3 (E3) on, and the retinotectal projection was subsequently analyzed at E16. DiI tracing analyses showed that although the projection of both temporal and nasal retinal ganglion axons in the tectum was, overall, normal, occasionally diffuse and extra termination zones were observed, in addition to axons over‐shooting their termination zones. These data support the idea that ephrin‐A2 contributes to the establishment of the chick retinotectal projection. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 245–254, 2001
Knowing is all: or is it? Some reflections on why the acquisition of knowledge, focusing particularly on evaluation activities, does not always lead to action
Authors: Cracknell Basil E. 
Published: September 2002

AbstractThis article examines the factors that influence whether the acquisition of knowledge leads on to action. It looks first at the ‘supply’ side, i.e. the kind of knowledge that is being acquired and whether it meets the needs of the intended users and is conducive to action; whether knowledge is a product or a process; the relevance of the positivist and constructivist approaches in this context; and whether participatory methods are required. The article then turns to the ‘demand’ side, and looks at possible reasons why decision‐takers may often seem to ignore new knowledge and evaluation findings. It suggests that evaluators may sometimes have unrealistic expectations of the kind of impact their reports should have. On the other hand there are factors leading to inertia and risk averseness that may stymie action. The importance of a ‘knowledge culture’ is emphasized if knowledge is to be turned into action. Copyright © 2001 John Wiley & Sons, Ltd.