bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micellar electrokinetic capillary chromatography with in situ charged micelles: II. Evaluation and comparison of octylmaltoside and octylsucrose surfactants as anionic borate complexes in the separation of herbicides
Authors: Smith Joel T. , Rassi Ziad El 
Published: May 2005

AbstractThis report is an extension of our previous work involving the development of in situ charged micellar phases with adjustable surface charge density for micellar electrokinetic capillary chromatography (MECC) of neutral and charged herbicides. The micelles evaluated here are basically alkyldisaccharide‐borate complexes in which the surface charge density can be conveniently varied by changing the operating parameters such as borate concentration and/or pH of the running electrolyte. The two alkyldisaccharide surfactants (i.e., octyl‐β‐D‐maltopyranoside and octylsucrose), having the same alkyl tail but differing in the nature of the sugar polar head group, were compared and characterized over a wide range of conditions using neutral and acidic herbicides as model solutes. The effects of the operating parameters are discussed in terms of mobility, elution range parameter, capacity factor, peak capacity, and separation efficiency. The retention energetics of the micellar phases were studied using two homologous series, alkylphenylketones and alkylbenzenes. At constant micellized surfactant concentration, the two in situ charged micellar phases exhibited homoenergetic retention behavior toward the homologous solutes. On the other hand, even though the two surfactants differed by the nature of one sugar residue in their polar head groups, the micelles exhibited different hydrophobic character, with octylmaltoside yielding higher retention.
Chemiluminescence detection in capillary electrophoresis
Authors: Baeyens Willy R. G. , Ling Betty Lin , Imai Kazuhiro , Calokerinos Anthony C. , Schulman Stephen G. 
Published: May 2005

AbstractCapillary electrophoresis techniques offer high plate numbers and are highly suited for the efficient separation of a wide variety of chemical components in diverse matrices. Because of the small capillary and detection cell dimensions, together with the minute volumes of samples to be injected, sensitive detection devices based on different physicochemical principles are being developed by various scientific groups and companies. The nature, possible applications and limitations of chemiluminescence as a detection technique are outlined in the present manuscript. The technique so far has only been explored by a limited number of research groups, and serious developments are to be expected for the coming years.
Characterization of continuous electrophoretic separations in narrow channels coupled to small bore capillaries
Authors: Mesaros Jody M. , Ewing Andrew G. 
Published: May 2005

AbstractContinuous electrophoretic separations in narrow channels have been carried out by coupling conventional capillary zone electrophoresis to open channel structures with rectangular cross sections. Presented here is an examination of the results of continuous separations conducted under various experimental conditions. The characterization is conducted using analysis of both continuous and plug injections of material into the channel, and the parameters used to analyze the separation are lateral dispersion, longitudinal dispersion, and signal intensity. Longitudinal dispersion indicates the amount of band broadening in the direction parallel to channel flow and, therefore, determines the spatial resolution of the separation. Lateral dispersion corresponds to band broadening perpendicular to channel flow and affects the accuracy with which the time of sample introduction into the channel can be determined. The results from these experiments indicate that (a) a cooled channel system provides better results when longer analyses are conducted, (b) a capillary step rate yielding a band introduction angle of 45 degrees relative to the direction of flow in the channel provides the best compromise between longitudinal and lateral dispersions (this value typically equals 0.9 s/25‐μm step for the system used in this research), (c) a capillary to channel linear velocity ratio of 3 to 5 yields improved signals relative to lower ratios due to more sample introduced (velocity ratios above this may lead to loss of spatial resolution), and (4) fast channel flows yield more symmetrically shaped bands than do slower flows due to more efficient transfer of material from the capillary‐channel junction into the channel. Detection limits of 41 μM are obtained with a linear range from 0.12 mM to 1.9 mM for laser induced fluorescence detection.
Electrochemical detection in open tubular column supercritical fluid chromatography using a platinum microelectrode and CO2/water as mobile phase
Authors: Almquist Susanne R. , Nyholm Leif , Markides Karin E. 
Published: May 2005

AbstractA miniaturized electrochemical detector for microcolumn separations has been developed. The detector was used in open tubular column supercritical fluid chromatography (SFC) with a mobile phase consisting of supercritical carbon dioxide with water below saturation. The detector is compatible with pressure programmed conditions, as is illustrated by the separation of ferrocene, acetylferrocene, and benzoylferrocene.
Electrokinetic chromatography of diterpenoid alkaloids from Aconitum sinomontanum Nakai
Authors: Song Liguo , Zhang Suoming , Ou Qingyu , Yu Weile 
Published: May 2005

AbstractThe separation of a hydrophobic mixture of diterpenoid alkaloids from Aconitum sinomontanum Nakai was studied using various modes of electrokinetic chromatography (EKC), such as SDS micellar EKC, methanol or N,N‐dimethylformamide modified micellar EKC, β‐cyclodextrin modified micellar EKC, mixed micellar EKC with SDS and PEG 400 monolaurate, and microemulsion EKC with SDS, n‐octane and n‐butanol. Mixed micellar EKC was found to be the most preferred approach.
An on‐line coupled HPLC‐HRGC system for the quantitative characterization of oil fractions in the middle distillate range
Authors: Beens Jan , Tijssen Robert 
Published: May 2005

AbstractA commercially available HPLC‐HRGC instrument was adapted to enable the full quantitative characterization of oil fractions in the range 150–400°C. The HPLC separates the sample into five fractions: saturates, mono‐aromatics, di‐aromatics, fluorenes + dibenzothiophenes, and tri‐aromatics. These fractions are subsequently quantitatively transferred via an on‐column interface to the HRGC part of the system. This transfer is performed into an empty, wide‐bore precolumn (retention gap), which enables a refocussing effect of the compounds of interest in the tail of the HPLC mobile phase, which acts as a solvent in the GC. A solvent vapor exit in the system enables the vent of the major part of this solvent. The final HRGC separation provides a carbon distribution of the saturates and the mono‐aromatics and enables the identification of a number of compounds in the other three fractions. It is demonstrated that the described method is quantitative for the hydrocarbons, but also for sulphur‐containing compounds in only those samples that have a low sulphur content. © 1995 John Wiley & Sons, Inc.
Separation of basic drugs by capillary electrophoresis using selectively modified cyclodextrins as chiral selectors
Authors: Weseloh Gerald , Bartsch Holger , König Wilfried A. 
Published: May 2005

AbstractThe influence of seven differently methylated β‐cyclodextrin derivatives and of pure β‐cyclodextrin (β‐CD) on the enantiomeric resolution by capillary electrophoresis of six basic chiral pharmaceuticals is investigated. The methyl substitution pattern affects enantioselectivity much more than other experimental parameters. The purity of the used cyclodextrin derivatives is analyzed by successive hydrolysis, reduction, acetylation, and GC/MS of each CD derivative and by MALDI‐TOF mass spectrometry. © 1995 John Wiley & Sons, Inc.
Large‐volume on‐column injections for gas chromatography
Authors: Ramalho Silvia , Hankemeier Thomas , de Jong Marco , Th. Brinkman Udo A. , Vreuls René J. J. 
Published: May 2005

AbstractLarge‐volume injection is an attractive means to improve detection limits when analyzing dilute sample extracts. There is now no need to achieve enrichment by means of solvent evaporation, which makes the total analytical procedure less reliable and less robust due to loss of volatile compounds. In this study on‐column injection was applied for large‐volume injection using an on‐column injector in combination with a deactivated uncoated fused silica capillary (retention gap) and an early solvent vapor exit. Two strategies are described. The first one relies on the programmable speed of an infusion pump, which is adapted such that it lies just above the evaporation rate of the extraction solvent used. With the second procedure, which can be used for a commercially available autosampler, the evaporation speed is adjusted to the fixed speed of injection by varying the temperature during injection. During optimization the additional solvent evaporation time was determined. The optimum conditions for an injection volume of 100 μL of either n‐hexane or ethyl acetate are reported. Large‐volume injection was used for simplified and miniaturized solid‐phase extraction procedures. The procedures were used to determine various organic micropollutants, such as organophosphorus pesticides and triazine herbicides, in tap and surface water extracts, using a flame photometric, and a mass spectrometric detector. For both methods good recovery for most of the analytes (70–87%), linear calibration curves (0.01‐5 μg/L range), and relative standard deviations of less than 10% were obtained. Detection limits typically were in the range of 1–10 ng/L for GC‐FPD and 10–150 ng/L for GC‐MS. When working in the time‐scheduled multiple ion detection mode detection limits in GC‐MS were one order of magnitude lower. © 1995 John Wiley & Sons, Inc.
GC instrumentation for on‐column injection of large volumes: Automated optimization of conditions
Authors: Munari Fausto , Colombo Pier Albino , Magni Paolo , Zilioli Giacinto , Trestianu Sorin , Grob Konrad 
Published: May 2005

AbstractImproved instrumentation facilitates on‐column injection of up to several hundreds of microliters onto GC capillary columns. It incorporates an autosampler with adjustable injection speed, a standardized precolumn system, an early vapor exit, and software that models evaporation of a given solvent at the flow and temperature conditions chosen by the user. The software calculates the appropriate injection speed, guides the autosampler correspondingly, and closes the vapor exit at a moment leaving in the precolumn the amount of unevaporated solvent that is selected by the user. © 1995 John Wiley & Sons, Inc.
Cyanobiphenyl‐substituted polymethylsiloxane encapsulated particles for packed capillary column supercritical fluid chromatography
Authors: Shen Yufeng , Li Wenbao , Malik Abdul , Reese Shawn L. , Rossiter Bryant E. , Lee Milton L. 
Published: May 2005

AbstractNine isomeric cyanobiphenyl‐substituted (25%) polymethylsiloxane (CBP) stationary phases were coated and immobilized by free‐radical crosslinking on silica packing materials for use in supercritical fluid chromatography (SFC). The selectivities of these packing materials to benzene derivatives, polycyclic aromatic hydrocarbons (PAHs), and double bonds in fatty acid methylesters (FAMEs) were determined. Among the nine isomeric CBP‐coated packing materials, the o, p‐CBP phase was found to be the most selective to both double bonds and aromatic isomers under SFC conditions. The durability of the packing materials was evaluated by measuring the changes in selectivity with SFC use. The loss in selectivity was less than 0.20% after being continuously washed by supercritical carbon dioxide at 100°C and 300 atm for more than 100 h.
Abnormal vestibuloocular reflex cancellation in multiple system atrophy and progressive supranuclear palsy but not in Parkinson's disease
Authors: Rascol O. , Sabatini U. , Fabre N. , Senard J. M. , Simonetta‐Moreau M. , Montastruc J. L. , Clanet M. , Rascol A. 
Published: May 2005

AbstractWe have measured the gain of the vestibuloocular reflex (VOR) in darkness and its cancellation by fixation in 37 patients with Parkinson's disease (PD), 26 patients with multiple system atrophy (MSA), 11 patients with progressive supranuclear palsy (PSP), and 19 normal volunteers. The capacity to cancel the VOR by fixation (VOR cancellation) was significantly reduced in the MSA and PSP patients compared with the PD and normal subjects (p < 10−4). A VOR cancellation < 90% (i.e., the mean VOR cancellation of the normals ‐ 2 SD) was present in four PD patients, 23 MSA patients, and 11 PSP patients. This criteria distinguished PD and MSA with a 89% sensitivity and a 89% specificity. Our results demonstrate that the VOR cancellation is impaired in most patients with MSA and PSP but not with PD. In MSA patients, the abnormal VOR cancellation is probably not related to the nigrostriatal dopaminergic deficit and more likely reflects a cerebellar dysfunction. Impaired VOR cancellation is a clinical criteria to differentiate MSA and PSP from PD.
A controlled investigation of current and premorbid personality: Characteristics of Parkinson's disease patients
Authors: Glosser Guila , Clark Christopher , Freundlich Bruce , Kliner‐Krenzel Lori , Flaherty Phyllis , Stern Matthew 
Published: May 2005

AbstractIt has been suggested that before development of motor symptoms, Parkinson's disease (PD) patients with idiopathic display a specific cluster of personality traits consisting of increased rigidity, conscientiousness, industriousness, orderliness, and cautiousness. The idea of such a distinctive premorbid personality profile remains controversial. This hypothesis was reexamined using a methodology that expands on previous studies. Patients with idiopathic PD, probable Alzheimer's Disease (AD), and medical controls with nonneurological chronic progressive motor disorders were rated by a close relative on the NEO‐Personality Inventory (PI) to compare current and premorbid personality profiles. For PD and control subjects, current and past self‐ratings were also obtained. Results do not support the postulated distinctive PD personality either premorbidly or following onset of symptoms. Both in terms of the premorbid personality profile and perceived changes in personality postdating the onset of illness, PD patients are similar to AD patients. Though not differing from medical controls premorbidly, after developing symptoms, PD patients were described as less extroverted; less exploratory and curious; and less organized, goal directed, and disciplined.
Prevalence of Parkinson's disease in junín, Buenos Aires province, argentina
Authors: Melcon Mario O. , Anderson Dallas W. , Vergara Rodolfo H. , Rocca Walter A. 
Published: May 2005

AbstractWe investigated the prevalence of Parkinson's disease (PD) in a South American city: Junín, Buenos Aires Province, Argentina. At dwellings systematically selected, the case finding involved household screenings and neurological examinations (i.e., a two‐phase survey approach). Only persons 40 years of age or older were eligible (N = 7,765). There were 51 cases of PD identified, yielding a crude prevalence of 656.8 per 100,000 population. The age‐specific prevalence was consistently higher in men than women, and it increased with advancing age for both sexes. In addition to prevalence figures, we present tallies related to clinical features of PD, as well as tallies related to other subtypes of parkinsonism.
A controlled trial of fluoxetine in nondepressed patients with Huntington's disease
Authors: Como Peter G. , Rubin Allen J. , O'Brien Chris F. , Lawler Kathy , Hickey Charlyne , Rubin Ann E. , Henderson Robin , McDermott Michael P. , McDermott Maria , Steinberg Kim , Shoulson Ira 
Published: May 2005

AbstractTo examine the antidepressant specificity of fluoxetine in Huntington's disease (HD), we carried out a randomized, double‐blind, placebo‐controlled trial of this medication in nondepressed HD patients. Thirty patients with early HD who were not depressed (Hamilton Depression Inventory <16) were randomized to placebo (N = 13) or fluoxetine 20 mg/day (N = 17) and were followed up for 4 months. Outcome measures included changes in total functional capacity (TFC) and in standardized neurological, cognitive, and behavioral ratings. After adjustment for the higher education level found in the placebo group at baseline, no differences between the treatment groups were found in TFC, neurological, or cognitive ratings. Fluoxetine‐treated patients did show a slight reduction in agitation and in the need for routine. Although fluoxetine may be a useful antidepressant in depressed HD patients, it failed to exert substantial clinical benefits in nondepressed HD patients.
Evidence for a new spinocerebellar ataxia locus
Authors: Higgins J. J. , Pho L. T. , Ide S. E. , Nee L. E. , Polymeropoulos M. H. 
Published: May 2005

AbstractThe autosomal dominant ataxias (ADA) are a diverse group of multisystem, neurodegenerative disorders characterized by mutations at several chromosomal loci (SCA types 1–5, SCA type 7, DRPLA). We excluded all the known SCA loci by mutational and linkage analyses in an American family of British origin with ADA and document that an additional ataxia locus must exist. The clinical characteristics and ethnic origin of our family are similiar to the British Drew family of Walworth with the SCA type 3 mutation and differ from other families without a known ataxia locus. Individuals in our family and the Drew family initially show signs of ataxia but may develop variable degrees of ophthalmoplegia, Parkinsonian features and central demyelination. The phenotypic diversity in families without a known ataxia locus suggests that there may be several other undefined ataxia loci.
Posttraumatic movement disorders after moderate or mild head injury
Authors: Krauss Joachim K. , Tränkle Rolf , Kopp Karl‐Heinz 
Published: May 2005

AbstractWe examined the occurrence of posttraumatic movement disorders after moderate or mild head injury with a three‐level follow‐up study including questionnaires, telephone interviews, and personal examinations 4–6 years after the trauma (mean 5.2 years). Sixteen of 158 patients (10.1%) for whom a detailed follow‐up was available had developed movement disorders most probably related to craniocerebral trauma. The most frequent finding was a low‐amplitude postural/intention tremor that appeared to resemble enhanced physiological or essential tremor. Twelve patients reported transient tremor, two patients had persistent tremor, one patient had transient tremor and persistent hyperekplexia, and another patient had mild persistent cervical myoclonic twitches. Overall, the movement disorder was transient in 12 patients (7.6%) and persisted in only 4 patients (2.6%). These movement disorders were not disabling and did not require medical therapy. Taking into account possible bias by selection of the sample group, the frequency of movement disorders secondary to moderate or mild head trauma might be lower than 10.1%. Posttraumatic movement disorders occurred significantly more often in the group of patients with Glasgow Coma Scores between 9 and 14 than in those with a score of 15. Severe movement disorders such as low‐frequency kinetic tremor or hemidystonia were not identified in this survey.
Teaching tape for the motor section of the toronto western spasmodic torticollis scale
Authors: Comella Cynthia L. , Stebbins Glenn T. , Goetz Christopher G. , Chmura Teresa A. , Bressman Susan B. , Lang Anthony E. 
Published: May 2005

AbstractThe Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) assesses the character and severity of cervical dystonia (CD). We developed a teaching tape of the TWSTRS scoring for the motor symptoms of CD. The tape provides investigators with visual representations of each component of the motor section of the TWSTRS as agreed upon by three independently scoring raters. The rate of agreement for the nondichotomous components was always significant, with a Kendall's coefficient of concordance W ranging between 0.98 and 0.76 (p < 0.01 for all measures). For the two dichotomous components, a weighted k coefficient was also significant at 0.86 for lateral shift and 0.89 for sagittal shift (p < 0.01 for both measures). Scale deficiencies identified by the raters were an explicit definition of midline for assessment of range of motion, the absence of a separate scoring category assessing dystonic tremor, and the specification of duration for the effect of sensory tricks. These observations should be taken into account in future revisions of the TWSTRS and in refinements of other rating scales for CD.
Gait initiation in parkinson's disease
Authors: Rosin Regina , Topka Helga , Dichgans Johannes 
Published: May 2005

AbstractWe studied the kinematic patterns of gait initiation in 31 patients with Parkinson's disease and in 20 age‐ and sex‐matched normals by using an optoelectronic tracking system (ELITE). Position markers were attached to the skin overlying the ankle, knee, hip, elbow, shoulder, and zygomatic bone. Subjects were instructed to start walking immediately after an acoustic go signal. Gait initiation was defined as the phase between standing motionless and steady‐state locomotion. This phase was subdivided into a movement preparation period (the time between go signal and movement onset) and a movement execution period (the time between movement onset and the end of the first stride). Onset and duration of ankle, knee, hip, trunk, and arm motion within the first stride were analyzed. Movement preparation time was significantly increased in Parkinson's disease (p = 0.01), whereas movement execution times were similar in both groups (p = 0.23). Initiation of ankle, knee, hip, arm, and trunk movements was delayed in patients as compared with healthy subjects, but the relative timing and the sequence of submovements was comparable in both groups, indicating that the overall pattern of submovements was preserved in the patients. Our data suggest that gait initiation deficits in Parkinson's disease cannot be explained by a disordered sequence of limb and trunk submovements. More likely, gait initiation problems originate from the basal ganglia's internal cueing deficit for movement sequences, delaying onset and slowing the execution of all subcomponents.
Cerebral glucose metabolism in corticobasal degeneration: Comparison with progressive supranuclear palsy and normal controls
Authors: Nagahama Yasuhiro , Fukuyama Hidenao , Turjanski Nora , Kennedy Angus , Yamauchi Hiroshi , Ouchi Yasuomi , Kimura Jun , Brooks David J. , Shibasaki Hiroshi 
Published: May 2005

AbstractThe regional metabolic rate of glucose was estimated using 18F‐labeled 2‐deoxyglucose and positron‐emission tomography (PET) in eight patients with corticobasal degeneration (CBD). Measures of cerebral glucose metabolism in these patients were compared with those for nine age‐matched normal controls and eight patients with progressive supranuclear palsy (PSP). Compared with that in the normal controls, the CBD patients showed significantly reduced cerebral glucose metabolism in the contralateral hemisphere to the clinically most affected side in the dorsolateral frontal, medial frontal, inferior parietal, sensorimotor, and lateral temporal cortex, as well as in the corpus striatum and the thalamus. In comparison with that in PSP, in CBD the glucose metabolism in the contralateral hemisphere was significantly decreased in the in ferior parietal, sensorimotor, lateral temporal cortex, and the corpus striatum. These results confirm the marked asymmetric cerebral involvement in CBD and suggest that there are significant differences between CBD and PSP in the cerebral metabolism in some cerebral regions such as the inferior parietal cortex and sensorimotor cortex, which might reflect the differences in their clinical characteristics.