bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of perfluorooctane sulfonate and perfluorooctanoic acid in human plasma by large volume injection capillary column switching liquid chromatography coupled to electrospray ionization mass spectrometry
Authors: Holm Anders , Wilson Steven R. , Molander Paal , Lundanes Elsa , Greibrokk Tyge 
Published: September 2004

AbstractRapid, selective, and sensitive methodology for the quantification of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in human plasma using packed capillary liquid chromatography coupled to electrospray ionization ion‐trap mass spectrometry has been developed. Plasma proteins were precipitated using acetonitrile and the resulting supernatant was diluted 1 + 1 with water containing 10 mM ammonium acetate (NH4Ac) prior to injection. Sample volumes of 250 μL were loaded onto a 30 mm×0.32 mm ID 10 μm Kromasil C18 precolumn by a carrier solution consisting of 10 mM NH4Ac in ACN/H2O (5/95, v/v) at a flow rate of 100 μL/min, providing on‐line analyte enrichment and sample clean‐up. Backflushed elution onto a 100 mm×0.32 mm ID 3.5 μm Kromasil C18 analytical column was conducted using an ACN/H2O solvent gradient containing 10 mM NH4Ac. In order to improve the robustness and performance of the method, perfluoroheptanoic acid (PFHA) was used as internal standard. Separation and detection of PFOA, PFHA, and PFOS were achieved within 10 minutes. Ionization was performed in the negative mode in the m/z range 250–550. The method was validated over the concentration range 1–200 ng/mL for PFOA and over the range 5–200 ng/mL untreated plasma for PFOS, yielding correlation coefficients of 0.997 (PFOA) and 0.996 (PFOS), respectively. The within‐assay (n = 6) and between‐assay (n = 6) precisions were in the range 2.1–9.2 and 5.6–12%, respectively. The concentration limits of detection (cLOD) of PFOA was 0.5 ng/mL while the cLOD of PFOS was estimated to be 0.2 ng/mL in untreated plasma.
Enantiomer separations on a vancomycin stationary phase and retention mechanism of pressurized capillary electrochromatography
Authors: Yao Chuanyi , Tang Shaokun , Gao Ruyu , Jiang Chun , Yan Chao 
Published: September 2004

AbstractSeveral chiral drugs, promethazine, carteolol, celiprolol, and albuterol, were resolved with vancomycin as the chiral stationary phase by pressurized capillary electrochromatography (pressurized CEC) and capillary HPLC. The effects of pressure and electrical field strength on efficiency, resolution, and capacity factor in pressurized CEC were investigated. A mathematical model describing the relationship of capacity factor in pressurized CEC with voltage, pressurized flow velocity, electroosmotic mobility, and electrophoretic mobility was established, which was in good agreement with the experimental data.
Function series with multifractal variations
Authors: Barral Julien , Seuret Stephane 
Published: September 2004

AbstractIn this paper, we study three classes of multifractal function series using a work achieved for a new class of measures defined in [3].The originality of these function series consists in the fact that the sizes of the jumps (or of the amplitudes of the pulses) depend on the location of the jump points and on a measure μ. In particular, there may be a strong heterogeneity in the distribution of the size of the jumps. These function series f are defined by

where ψj,k is a contracted and dilated version of a single function ψ. This function ψ will either be a wavelet, a pulse, or a piecewise linear function.We show that under suitable conditions on the measure μ, the multifractal spectrum of f can be computed. For large classes of measures, the spectrum is linear between 0 and a critical value hc, and if h ≥ hc, f and μ share the same spectrum. This untypical shape is the result of the combination of the multifractal measure μ with the rapid variations or discontinuities of the functions ψj,k. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Technology and Stress Relaxation of Biaxially Oriented Polyolefin Shrink Films
Authors: Bobovitch Arthur , Unigovski Yakov , Jarashneli Albert , Gutman Emmanuel M. 
Published: September 2004

AbstractIn the present study the influence of the heating rate on the stability of the double bubble technological process was investigated. It was shown that increasing the heating rate decreases the stability of the process and causes the lower elongation of the films produced. The morphological transformations of linear low density polyethylene (LLDPE) film were explained using X‐ray and transmission electrom microscopy (TEM) methods. The stress relaxation behavior of co‐extruded LLDPE/ethylene‐vinyl‐acetate (EVA) film was studied using the relaxation time spectrum approach. The influence of vinyl‐acetate (VA) content in EVA copolymers on the relaxation time spectrum was observed.
New Approaches for the Development of Highly Stable Polypropylene
Authors: Terano Minoru , Liu Boping , Nakatani Hisayuki 
Published: September 2004

AbstractEffects of primary structure on the degradation of polypropylene (PP) were studied using PPs having a variety of tacticities or a random ethylene sequence with the aim of improving the stability of PP. Thermal stabilities of isotactic, atactic and syndiotactic PPs (iPP, aPP and sPP) having similar molecular weights were investigated in terms of stereoregularity under the same conditions. The sPP showed the highest stability, suggesting that the racemic structure of the main chain interferes with the chain reaction of radical species. Moreover, iPP was prepared to evaluate the thermal stability with a random ethylene sequence (ethylene‐propylene random copolymer: rPP). The rPP was more stable than iPP. The existence of the ethylene sequence in the main chain was found to be effective in achieving high stability.
From Mumford–Shah to Perona–Malik in image processing
Authors: Kawohl B. 
Published: September 2004

AbstractIn mathematical image processing we are often presented with amazing examples of image enhancement algorithms. Yet, when applied to different noisy images, they can produce unwanted effects. The analysis of such algorithms lags behind their intuitive development. Two essentially different models have found wide recognition: a variational approach due to Mumford and Shah, and an anisotropic diffusion approach leading to an evolution type equation by Perona and Malik. In this survey we shall explain a surprising connection between these two approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Broadband high‐efficiency microstrip antenna array with corporate‐series‐feed
Authors: Lee Byungje , Kang Gi‐Cho , Yang Sung‐Hyun 
Published: September 2004

AbstractA linearly polarized microstrip antenna array in the Ku‐band achieves high efficiency by having the proper impedance matching throughout the array and by properly using the corporate and series feeds with microstrip transmission lines. The efficiency of the antenna array is 83.3%. The cavity‐backed microstrip patch is used as the element of the antenna array to obtain relatively wide bandwidth. The auto‐tracking antenna in the azimuth direction is developed with a very low profile as well as a low manufacturing cost for the vehicle's rooftop mounting. The main beam of array is tilted 15° away from the broadside direction to provide optimum coverage for Korea satellite III. The measured gain of an antenna array is 23.8 dBi at the center frequency of 12.5 GHz. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 181–183, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20413
Wideband circularly polarized radial stub fed slot antenna
Authors: Rao Patnam H. 
Published: September 2004

AbstractWideband circular polarization with a boresight axial ratio of ≤ 2.2 dB is achieved over 35% of bandwidth by sequential rotation of linearly polarized radial stub‐fed slot elements (2 × 2 array). The effect of the feed interactions upon the antenna radiation pattern is also analysed. The impedance bandwidth of the antenna is 40%, centered at 2.1 GHz for VSWR ≤ 1.5. The average measured gain of the antenna is 3 dB. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 211–213, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20421
High‐efficiency generation of cladding pumped Erbium‐ytterbium co‐doped double clad fiber ring laser operating in L‐band
Authors: Shu‐Min Zhang , Fu‐Yun Lu , Jian Wang , Fa‐Jie Dong , Hongjie Wang , Xiaoyi Dong 
Published: September 2004

AbstractA novel Er3+/Yb3+ co‐doped double‐clad fiber‐ring laser, which utilizes amplified spontaneous emission as a secondary pump source in order to operate in L‐band, is demonstrated. Six laser diodes are used to cladding‐pump Er3+/Yb3+ co‐doped double‐clad fiber. When the pumping power of entering fiber is 2731.8 mW, the maximum output power is 518.4 mW, and the slope efficiency is 19%. The relationship between the output power and the splitting ratio of the output coupler is also studied in this paper. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 213–215, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20422
Comparison between two stable hybridized 2D generalized FDTD algorithms for multiscale analysis
Authors: Marrone M. , Mittra R. 
Published: September 2004

AbstractIn this paper, we carry out a numerical comparison between two hybrid 2D generalized finite‐difference time‐domain (FDTD) algorithms, designed to analyze objects with fine details, without using the very small time steps dictated by the Courant condition. We evaluate the accuracy and the computational complexity of the above algorithms, employing either subgridding or triangular gridding to model the fine details. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 221–225, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20424
Guide wavelength estimation of sandwich‐type double‐layer slotline
Authors: Han Ki Jin , Kim Jeong Phill 
Published: September 2004

AbstractA novel approximate method for estimating the guide wavelength of a double‐layer slotline is presented. The guide wavelength curve of a physically symmetric double‐layer slotline is estimated from the data of two special types of slotline. A linear combination of two curves in the former approximation is used for a general double‐layer slotline. The results of the proposed method are compared with numerical computation and its high level of accuracy is confirmed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 261–264, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20437
Complete assignment of 1H and 13C NMR data for three aryltetralin lignan lactones
Authors: da Silva Rosangela , Heleno Vladimir Constantino Gomes , de Albuquerque Sérgio , Bastos Jairo Kenupp , e Silva Márcio Luis Andrade , Donate Paulo Marcos , da Silva Gil Valdo José 
Published: September 2004

AbstractWe describe the complete 1H and 13C NMR analysis of three aryltetralin lignan lactones (polygamain, morelensin and 4,5‐dimethoxymorelensin) using modern NMR techniques such as COSY, HMQC, HMBC, 2D‐J‐resolved and NOE experiments. The relative stereochemistry of these compounds, which is very important with regard to their biological activity, was completely determined. Copyright © 2004 John Wiley & Sons, Ltd.
Sleep disorders, epilepsy, and autism
Authors: Malow Beth A. 
Published: September 2004

AbstractThe purpose of this review article is to describe the clinical data linking autism with sleep and epilepsy and to discuss the impact of treating sleep disorders in children with autism either with or without coexisting epileptic seizures. Studies are presented to support the view that sleep is abnormal in individuals with autistic spectrum disorders. Epilepsy and sleep have reciprocal relationships, with sleep facilitating seizures and seizures adversely affecting sleep architecture. The hypothesis put forth is that identifying and treating sleep disorders, which are potentially caused by or contributed to by autism, may impact favorably on seizure control and on daytime behavior. The article concludes with some practical suggestions for the evaluation and treatment of sleep disorders in this population of children with autism. MRDD Research Reviews 2004;10:122–125. © 2004 Wiley‐Liss, Inc.
Epileptic encephalopathies and their relationship to developmental disorders: Do spikes cause autism?
Authors: Tharp Barry R. 
Published: September 2004

AbstractEpileptic encephalopathies are progressive clinical and electroencephalographic syndromes where deterioration is thought to be caused by frequent seizures and abundant EEG epileptiform activity. Seizures occur in approximately 10–15% of children with pervasive developmental disorders (PDD) and 8–10% have epileptiform EEG abnormalities without seizures. Thirty percent of children with PDD have regression of social behavior and language at 2–3 years of age. Some authors speculate that the regression is caused by epileptiform activity even in the absence of overt clinical seizures (“autism with epileptic regression”) and suggest that elimination of the epileptiform activity, either medically or surgically, should lead to improvement in behavior. This review examines the data showing that interictal epileptiform discharges are associated with transient clinical dysfunction and discusses the implications of these observations for autistic behavioral abnormalities. The results of resective surgery, vagal nerve stimulation, and multiple subpial transaction on children with autism and epileptiform EEG abnormalities are also discussed. I conclude that there is no evidence that interictal dischargesper secause (or contribute to) the complex behavioral phenotype of autism. There is no justification to support the use of anticonvulsant medication or surgery in children with PDDwithout seizures; that is,there is no evidence that treatmentto eliminate EEG spikes will have a therapeutic effect on the behavioral abnormalities of PDD and autism. MRDD Research Reviews 2004;10:132–134. © 2004 Wiley‐Liss, Inc.
Lennox–Gastaut syndrome: Potential mechanisms of cognitive regression
Authors: Blume Warren T. 
Published: September 2004

AbstractLennox–Gastaut (L‐G) syndrome is an intractable generalized epilepsy of childhood onset, associated with spike waves at a slow rate and paroxysmal fast activity. These epileptiform discharge patterns are thought to reflect excessive neocortical excitability and arise from neuronal and synaptic features peculiar to the immature central nervous system. The epileptic processes associated with L‐G syndrome may lead to enduring patterns of abnormal activity and connectivity. These abnormal patterns compete with normal developmental mechanisms and may result in subsequent impairment and/or regression of cognition. Recurring or prolonged seizures themselves may also damage the brain. We hypothesize that the presence of slow spike waves diverts the brain from normal developmental processes toward seizure‐preventing mechanisms. Adding to this burden, antiepileptic medications, sleep disruption, and social isolation all retard cognitive development and the learning process at a crucial time of brain maturation. MRDD Research Reviews 2004;10:150–153. © 2004 Wiley‐Liss, Inc.
Rett syndrome: Of girls and mice—Lessons for regression in autism
Authors: Glaze Daniel G. 
Published: September 2004

AbstractRett syndrome (RTT) is a neurodevelopmental disorder occurring almost exclusively in females. Regression is a defining feature of RTT. During the regression stage, RTT girls display many autistic features, such as loss of communication and social skills, poor eye contact, and lack of interest, and initially may be given the diagnosis of autism. The discovery of the genetic cause of RTT, mutations in the MECP2 gene, a transcriptional repressor, has promoted the early diagnosis of RTT and development of mouse models. The phenotype of one mouse model includes features such as regression and abnormal behavioral and social interactions. The timing of the period of regression in RTT—during ages 1 to 2 years—parallels the period of intense synaptic development. The effects of the MECP2 mutation also increases concomitantly with peak synaptogenesis. Neuropathological findings in Rett include the selective reduction of dendritric spines in the pyramidal cells of RTT brains; this feature has also been reported in autism. Studies have observed that MECP influences the expression of brain‐derived neurotrophic factor and thus may influence synaptic plasticity. Abnormalities in synapse maintenance and modulation may contribute to regression in RTT and autism. Studies of the clinical aspects of the regression period and of the mouse model may be useful in understanding the pathophysiology of RTT and other neurodevelopmental disorders such as autism. A recent study observed abnormal expression of MeCP2 in RTT and other neurodevelopmental disorders such as autism. Although the genetic background and certain clinical features differ in RTT and autism, a similar mechanism involving MeCP2 regulation and expression may contribute to regression. MRDD Research Reviews 2004;10:154–158. © 2004 Wiley‐Liss, Inc.
Assessment of recovery following a novel partial nerve lesion in a rat model
Authors: Malushte Tejashree S. , Kerns James M. , Huang Chris C. , Shott Susan , Safanda John , Gonzalez Mark 
Published: September 2004

AbstractPartial nerve lesions with a varying degree of retained function and often a painful neuroma pose a dilemma for the clinician. Surgical treatment of partial nerve lesion is perilous because of possible damage to intact axons and subsequent loss of retained function. We present a new rat model of a partial nerve lesion, allowing further study to improve treatment for this condition. A partial (50%) lesion of the tibial portion of the rat sciatic nerve was created and compared to standard crush and neurectomy control lesions. The extent of lost function and the progress of postoperative recovery following the three lesions were compared using serial walking track analyses and end‐point muscle weight ratios for atrophy as outcome measures. All groups had tibial functional indices (TFI) significantly different from one another after 1 week. TFIs for the crush group returned to normal by 4 weeks, whereas the neurectomy group showed no recovery. The partial lesion group gradually improved, reaching a plateau of 44% by 7 weeks. Gastrocnemius muscle weight ratios for the partial, crush, and neurectomy lesions at 9 weeks were 0.63, 0.87, and 0.32, respectively. There was a strong correlation between the TFI and muscle weight ratios (r2 = 0.89; P < 0.001) suggesting that these outcome measures are highly predictive of function. In conclusion, the partial lesion showed a gradual but incomplete functional recovery with a complementary degree of muscle atrophy. The model may prove useful in the evaluation of proposed treatments for partial nerve lesions and the associated painful state. Muscle Nerve 2004
Fatigue of rat hindlimb motor units: Biochemical– physiological associations
Authors: Callister Robert J. , Sesodia Sanjay , Enoka Roger M. , Nemeth Patti M. , Reinking Robert M. , Stuart Douglas G. 
Published: September 2004

AbstractAssociations between fatigability and biochemical properties within motor unit (MU) types were explored in two hindlimb muscles of the adult rat. Type FF MUs in extensor digitorum longus and type S units in soleus were subjected either to a moderate (type FF) or severe (type S) 6‐min, fatigue‐inducing stimulation protocol. For both MU types, the range of values for their fatigability was considerably greater than the ranges in the activity levels of three enzymes in the units' constituent muscle fibers (MFs). These enzymes represented major energy‐yielding pathways: adenylokinase, for high‐energy phosphate metabolism; lactate dehydrogenase, for anaerobic glycolysis; and malate dehydrogenase, for oxidative metabolism. There were also relatively weak associations between the fatigue indices of the MUs and the activity levels of the three enzymes. Thus, this work supports previous conclusions that the force decline exhibited by MUs during electrically evoked contractions depends on both MF biochemistry and other intracellular mechanisms. Electromyographic measurements suggested that these other mechanisms are distal to the intramuscular branches of the axon in type FF units, and distal to excitation–contraction coupling in type S units. Muscle Nerve, 2004
Physiotherapy for female stress urinary incontinence: Individual therapy at the outpatient clinic versus home‐based pelvic floor training: A 5‐year follow‐up study
Authors: Parkkinen A. , Karjalainen E. , Vartiainen M. , Penttinen J. 
Published: September 2004

AbstractAimsTo compare the long‐term effects of individual physiotherapy at an outpatient clinic, including electrical stimulation (ES), active pelvic floor muscle exercises (PFMEs), and training with a vaginal ball (VB), with home‐based active PFMEs and training with a VB, in cases of female stress urinary incontinence (SUI).Materials and MethodThirty‐three women with SUI (outpatient clinic group [Group I, n = 16] and home group [Group II, n = 17]) participated in the 5‐year follow‐up study. Both groups had an active PFME program and they used a VB during daily activities for intensive pelvic floor muscle (PFM) training. Group I was also treated at the outpatient clinic with maximal interferential ES, using frequencies varying from 10 to 50 Hz, and individually instructed exercises with biofeedback were carried out at the same time, once a week, an average of nine times in the first year. After baseline examinations, both groups visited the outpatient clinic at 4 months, 12 months, and at 5 years.ResultsAt 12 months, there were no statistically significant differences between the study groups in any of the outcome variables, but within the groups both the subjective and objective results were significantly better in comparison with the initial values. After 12 months, two (3%) patients in Group I continued physiotherapy and seven (41%) patients in Group II needed physiotherapy because of an unsatisfactory outcome. At 5 years, according to the urinary incontinence severity score (UISS) questionnaire, subjective discomfort had decreased in both groups (P < 0.01) and 21 of the 33 women (64%) perceived a subjective cure or improvement in their condition. The mean objective urine leakage verified by the pad test decreased from 23.0 to 1.0 g in Group I and from 13.0 to 1.0 g in Group II (P < 0.001 for both groups). The strength of PFMs tested in a standing position increased by 26% in Group I and by 19% in Group II (P values 0.001 and 0.084, respectively), and in a lying position by 28% in Group I and by 32% in Group II (P values 0.001 and 0.008, respectively).ConclusionsHome‐based PFMEs and training with a VB proved to be equally effective as once‐a‐week supervised therapy, and the 5‐year follow‐up results demonstrated a successful response in the treatment of female SUI. © 2004 Wiley‐Liss, Inc.
Sojourn times in a two‐stage queueing network with blocking
Authors: Gómez‐Corral A. 
Published: September 2004

AbstractThe model considered in this paper involves a tandem queue consisting of a sequence of two waiting lines. The main feature of our model is blocking, i.e., as soon as the second waiting line reaches a certain upper limit, the first line is blocked. The input of units to the tandem queue is the MAP (Markovian arrival process), and service requirements are of phase type. Our objective is to study the sojourn time distribution under the first‐come‐first‐serve discipline by analyzing the sojourn time through times until absorption in appropriately defined quasi‐birth‐and‐death processes and continuous‐time Markov chains. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004