bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of the dissociation constant for unreacted silanol groups on the surface of ODS‐silica from the relationship between ph and electroosmotic flow velocity in capillary electrochromatography
Authors: Kitagawa Shinya , Tsuda Takao 
Published: May 2005

AbstractElectroosmotic flow in electrochromatography is generated by surface charges on the packing materials under an applied voltage. The surface charge density of ODS‐silica gel is increased by dissociation of unreacted silanol groups, and the dissociation constant is dependent on pH. We have developed an equation for the relationship between pH and electroosmotic flow velocity. By using this equation, we estimate the dissociation constant of unreacted silanol groups from their relationships in electrochromatography to be 10−4.3.The proposed method has the following features: (1) the dissociation constant can be estimated in situ by using a column for electrochromatography or capillary electrophoresis without any alteration of the instrumentation, and therefore (2) the dissociation constant obtained is directly useful for the selection of separation conditions.
Effects of buffer concentration on the electrophoretic behaviors of small peptides in capillary zone electrophoresis
Authors: Chen Nong , Wang Lei , Zhang Yukui 
Published: May 2005

AbstractIt was found that unlike the electroosmotic flow, the electrophoretic mobilities of small peptides in capillary zone electrophoresis (CZE) were invariant over the buffer concentration range studied. Migration of these peptides in CZE is a electroosmotic‐governed process. The quantitative linear relationships between the logarithm of migration times (log tm) and the reciprocal of column temperature were investigated under different buffer concentrations to study the activation energies of diffusion (AED) as the function of the buffer concentration. The preexponential factors were quantitatively correlated with the structural parameters of the peptides studied. © 1995 John Wiley & Sons, Inc.
Comparison of selectivities for PCBs in gas chromatography for a series of cyanobiphenyl stationary phases
Authors: Hillery Barbara R. , Girard James E. , Schantz Michele M. , Wise Stephen A. , Malik Abdul , Lee Milton L. 
Published: May 2005

AbstractSelectivity for polychlorinated biphenyl (PCB) congeners was examined for a series of cyanobiphenyl stationary phases, and the results were compared to a nonpolar 5% phenyl methylpolysiloxane phase and a shape‐selective smectic liquid crystalline phase. For all of the columns studied, the degree of ortho substitution of the congener was found to be a significant factor controlling chromatographic retention of PCBs. The retention pattern on six different cyanobiphenyl phases followed the same general pattern as on the liquid crystalline column, though the trends were more exaggerated on the liquid crystalline phase. While the general retention pattern was similar for all of the cyanobiphenyl phases studied, subtle differences were observed, resulting in significant selectivity differences. For isomeric planar PCB congeners, elution order could be correlated to length‐to‐breadth ratios. Among the cyanobiphenyl phases, the p,p‐ and the o,p,p‐cyanobiphenyl phases had the greatest enhancement of retention for planar congeners. A shapeselective test mixture reflected the similarity of retention on the cyanobiphenyl phases to both the 5% phenyl methylpolysiloxane phase and the smectic liquid crystalline phase. © 1995 John Wiley & Sons, Inc.
Investigation of parameters affecting the supercritical fluid extraction of polymer additives from polyethylene
Authors: Lou Xianwen , Janssen Hans‐Gerd , Cramers Carel A. 
Published: May 2005

AbstractPolymer additives were extracted from polyethylene with supercritical carbon dioxide. The two‐film theory, which considers mass transfer across a phase boundary, is applied to qualitatively describe the kinetics of mass transfer from the core of the polymer particles into the supercritical fluid extractant. The effects of pressure, temperature, addition of benzene as a modifier, properties and concentrations of the solutes, static time, and supercritical fluid extractant flow rate on the extraction process are investigated systematically. At constant temperature the extraction rates first increase with increasing pressure. When pressure reaches a certain level, a further increase of the pressure does not further increase the extraction rates. At constant pressure, the extraction rates were found to increase first and then decrease with increasing temperature. In addition to pressure and temperature, the SFE extraction kinetics is also influenced by the solute concentration, and the rate‐limiting parameter in the extraction can be changed from solubility to diffusion during the course of the extraction. The magnitude of the effects of the experimental parameters depends on the properties and molecular weights of the solutes. The role of benzene as a modifier in the extraction of polymer additives from polyethylene is swelling the polymer particles and improvement of the solvent strength of the supercritical fluid extractant. Modifier effects were found to be more pronounced at lower temperatures. © 1995 John Wiley & Sons, Inc.
Capillary electrophoresis using air and helium as cooling fluids
Authors: Cifuentes Alejandro , Kok Wim Th. , Poppe Hans 
Published: May 2005

AbstractA comparative study on the properties of helium and air as thermostatting fluids in Capillary Electrophoresis (CE) has been carried out. Equations that relate the properties of fluids to their control of the temperature of the capillary are shown. Results from theory and experiments are compared under different cooling conditions, i.e., natural and forced gas convection, using air and helium. Experimental results are qualitatively in good agreement with those predicted by theory. The better thermostatting capability of helium compared to air is demonstrated by an improved efficiency in real separations and a lower degree of denaturation of a thermolabile protein during its purification by CE. © 1995 John Wiley & Sons, Inc.
Modifier addition in microcolumn supercritical fluid chromatography
Authors: Robson Mark M. , Raynor Mark W. , Bartle Keith D. , Clifford Anthony A. 
Published: May 2005

AbstractRecent advances in techniques for the packing of microcolumns of down to 50 μm inner diameter using supercritical CO2 have led to rapid growth in the use of high efficiency packed capillary columns in SFC. Maximization of the usefulness and applications of these techniques requires gradient elution chromatography and the development of pumps capable of delivering 0.1 to 1 μl per minute of modifier. A micro SFC‐LC pump has been tested in the isocratic and gradient elution mode with CO2 as the supercritical fluid and methanol as the modifier. The pump was tested using the EPA priority PAHs as the test mixture with a specially treated ODS column and UV detection. Results are presented for testing in the isocratic and gradient elution modes and the retention times are shown to have a coefficient of variation of less than 2%. The application of this system to the analysis of PAHs in coal derivatives is shown. The problems encountered in the use of formic acid as a modifier in SFC are discussed. © 1995 John Wiley & Sons, Inc.
Analytical separation of Trichoderma Reesei cellulases by Capillary Zone Electrophoresis
Authors: Khaled Maha Y. , McNair Harold , Polite Lee , Pauls Richard 
Published: May 2005

AbstractThe Capillary Zone Electrophoretic separation of the four common enzymes of Cellulase, the endo‐(EG I, EG II) and the exo‐(CBH I, and CBH II) glucohydrolases from the fungi Trichoderma Reesei, is presented. The separation using underivatized fused silica capillaries with 0.03 M Na2HPO4 at an optimum pH of 9.2 proved successful, rapid, and reproducible. Variations in buffer type, ionic strength, pH, temperature, and reduced electroosmotic flow and their effects on the separation were investigated revealing a significant effect on the efficiency, the separation, and the integrity of the enzymes. © 1995 John Wiley & Sons, Inc.
Direct analysis of cortisol and cortisone in human urine by semi‐microcolumn liquid chromatography with mixed‐function precolumn
Authors: Kanda Taketoshi , Shirota Osamu , Ohtsu Yutaka , Yamaguchi Michihiro 
Published: May 2005

AbstractA column‐switching system based on semi‐microcolumns is constructed for direct analysis of cortisol and cortisone in human urine samples. Urine samples (100 μl) were directly injected into a polymer‐coated mixed‐function (PCMF) column (35 mm × 1.5 mm i.d.), which removes proteins and fractionates an analyte‐containing zone. The analyte‐containing fraction was thereafter transferred to a C18 semi‐microcolumn (250 mm × 1.5 mm i.d.). The analytes were monitored with ultraviolet (UV) absorption at 242 nm, with the detection limit for cortisol and cortisone, 3 pmol/mL (at a S/N ratio of 5) for each. The system showed quantitative results for dilute standard samples using human urine as a solvent. The method could be applied to the routine assessment of cortisol and cortisone in human urine. © 1995 John Wiley & Sons, Inc.
Characterization of the physiological condition of Eucalyptus globulus labil by headspace HRGC analysis of the bouquet of odors
Authors: Mateus Eduardo P. , Farrall Maria H. , Paiva M. Rosa 
Published: May 2005

AbstractThe borer Phoracantha semipuntacta originates from Australasia and has spread to Africa, Europe, and America where it attains major pest status on eucalyptus crops. However, in an eucalyptus stand not all trees are equally attractive to females of P. semipunctata searching for ovipositing sites. Previous studies indicate a non‐random host selection process in which olfactory stimuli play an important role. Field experiments, conducted to decode the mechanisms of primary attraction, showed that eucalyptus logs originating from trees already attacked by the borer captured significantly more adults and eggs of P. semipunctata than the ones cut from vigorous trees. A High Resolution Gas Chromatography‐Head Space (HRGC‐HS) technique was used, to analyze and compare the profiles of the volatiles emitted by attacked, and unattacked E. globulus. Identification of the chromatographic peaks was achieved by GC‐MS. Significant differences were found between the two types of trees, particularly in the contents of α‐phellandrene, α‐pinene, and p‐cymene. A relationship between tree physiological condition—attacked or unattacked—and the bouquet of odors emitted was thus established.
The effects of cisapride on plasma L‐dopa levels and clinical response in Parkinson's disease
Authors: Neira Walter Diaz , Sanchez Vicenta , Mena Maria Angeles , de Yebenes Justo Garcia 
Published: May 2005

AbstractCisapride (CIS) is a prokinetic agent that increases gastrointestinal motility in normal individuals and improves constipation in Parkinson's disease (PD). We studied the effects of CIS on the clinical response and the peripheral pharmacokinetics of orally administered L‐dopa given to patients with PD. Twenty patients with idiopathic PD and chronic constipation, whose response to L‐dopa was suboptimal or characterized by fluctuations, agreed to participate in an open study that lasted for 2 weeks. Fourteen patients completed the study (mean age 65 ± 9.3 years, mean duration of treatment 5.7 ± 4.2 years, mean L‐dopa daily doses 658.9 ± 269.9 mg); six patients were excluded due to lack of compliance or changes in medication during the study. The end points of the study included the mean levels of L‐dopa, the height of the peak of L‐dopa in plasma, mean plasma levels of 3‐OM‐dopa, and the speed and quality of gait and visuomanual corrdination before and during treatment with CIS. CIS increased peak plasma levels of L‐dopa by 37% and the mean plasma levels of L‐dopa by 13% with respect to those obtained with the same dose of L‐dopa before the addition of CIS. Therefor, CIS appears to increase early absorption of L‐dopa through acceleration of gastric emptying. CIS also increased plasma 3‐OM‐dopa levels, improved visuomanual coordination, and reduced gait disability. CIS improves gastrointestinal function and response to L‐dopa in patients with PD and could be a helpful add‐on medication in these patients.
Frontal and parietal premovement slow brain potentials in Parkinson's disease and aging
Authors: Bötzel K. , Mayer M. , Oertel W. H. , Paulus W. 
Published: May 2005

AbstractDuring the anticipation of a stimulus that induces a predetermined pattern of behavior, a slowly increasing negative electric potential can be recorded from the human scalp at central and parietal electrodes and has been named contingent negative variation (CNV). We used a simple and a choice reaction time paradigm to investigate premovement potentials in patients with Parkinson's disease (PD) and in normal controls. There was a clear CNV in young subjects whereas it was negligible in the elderly control subjects and absent in the patients. In addition, we found a slowly increasing positive frontal potential. In normals the steepness of this potential decreased with the complexity of the task (simple vs. choice) and with age. This difference was abolished in the patients: If a slowly increasing positivity was observed at all, it was, on average, larger in the choice task. Reaction times of the patients were disproportionally prolonged in the simple compared to the complex task. These findings support the hypothesis that storing or initiating a simple preprogrammed motor response is more impaired in PD than selecting and initiating a motor response of a more complex task. The electrophysiological recordings suggest that impaired activation of the frontal lobes may be responsible for this deficit.
Tourettism associated with Huntington's disease
Authors: Jankovic Joseph , Ashizawa Tetsuo 
Published: May 2005

AbstractThe identification of the gene for Huntington's disease (HD) has made it possible to diagnose patients with HD who present with unusual or atypical features. We describe a 41‐year‐old man whose intial manifestation of HD was dominated by the presence of motor and vocal tics and other features of Tourette's syndrome. This case illustrates the broad range of clinical manifestation of HD and the usefulness of testing for the HD mutation in selected cases with familial movement disorders.
Psychiatric symptoms, atypical dementia, and left visual field inattention in corticobasal ganglionic degeneration
Authors: Rey G. J. , Tomer R. , Levin B. E. , Sanchez‐Ramos J. , Bowen B. , Bruce J. H. 
Published: May 2005

AbstractWe longitudinally examined the neuropsychological and psychiatric characteristics of an adult male with pathologically confirmed corticobasal ganglionic degeneration (CBGD). The patient was seen on an inpatient and outpatient basis by members of the Departments of Neurology and Radiology of the University of Miami School of Medicine. Longitudinal neuropsychological testing revealed a lateralized cortical‐subcortical dementia and left visual field inattention consistent with neurological and postmortem neuropathological findings of greater right hemisphere dysfunction. Symptoms of depression and obsessive‐compulsive symptomatology were also documented. Our findings are consistent with prior reports indicating that CBGD is characterized by lateralized cerebral dysfunction and suggest that a detailed neuropsychological examination is a useful procedure to assist in the differential diagnosis of this movement disorder.
Spread of symptoms in idiopathic torsion dystonia
Authors: Greene Paul , Kang Un Jung , Fahn Stanley 
Published: May 2005

AbstractWe reviewed the histories of 115 patients who had idiopathic dystonia and who were 21 years of age and younger at onset of symptoms and 472 patients with older than age 21. Patients with onset in the lower extremities tended to be younger at onset (mean age 8.4 years), have rapid spread of symptoms to other body parts, and to develop generalized dystonia. Patients with onset in the upper extremities tended to be older at onset (mean age 11.2 years) and were less likely to develop generalized dystonia, but were more likely to experience spread of symptoms many years after the disease began. Almost 20% of patients younger than age 22 began with torticollis, and 67% of these remained focal after a mean 14.9 years. In adults, dystonic symptoms remained focal in the majority, but ∼ 15–30% of patients presenting with blepharospasm, torticollis, laryngeal or brachial dystonia eventually experienced dystonia outside the initially involved segment. Almost 50% of children and adolescents with dystonia reported a family history of dystonia, compared with ∼ 10–13% of patients with torticollis, laryngeal or brachial dystonia. Less than 3% of patients with blepharospasm reported a family history of dystonia. There were only minor differences in the pattern of spread of dystonic symptoms between Jewish and non‐Jewish patients. Although younger patients were more likely to report a family history of dystonia, patterns of spread were the same for familial and sporadic patients in the same age range.
Patterns of regional cerebral blood flow in corticobasal degeneration studied using HMPAO SPECT; comparison with Parkinson's disease and normal controls
Authors: Markus H. S. , Lees A. J. , Lennox G. , Marsden C. D. , Costa D. C. 
Published: May 2005

AbstractCorticobasal degeneration (CBD) is a rare syndrome characterised by an asymmetrical rigidity with localised cortical signs, particularly apraxia. Using positron emission tomography, abnormal patterns of cortical metabolism have recently been shown. We have studied patterns of regional cerebral blood flow (rCBF) using single photon emission tomography, with the tracer 99Technetium hexamethylpropylenamine (HMPAO), in subjects with CBD. In subjects with CBD, compared with 12 age‐matched normal controls, in the clinically more affected hemisphere a characteristic pattern was found with significant reductions in HMPAO uptake in the posterior frontal cortex (by 11.5%), and in the superior, inferior, anterior, and posterior parietal cortex (by 12.2, 12.9, 12.9, and 9.7, respectively). Reduced uptake was also found in the caudate (9.3%), putamen (9.7%), and thalamus (8.6%). In contrast, HMPAO uptake in the temporal and occipital cortex was normal. In comparison with 12 Parkinson's disease (PD) controls, significant reduced uptake was seen in the thalamus (9.0%), posterior frontal (8.9%), and inferior (9.9%), and anterior parietal (9.5%) cortex. A similar pattern of impaired uptake was seen in the clinically les/unaffected cerebral hemisphere in patients with CBD compared with normal controls, with a significant reduction in HMPAO uptake in the thalamus (6.8%), superior parietal (9.6%) and anterior parietal (7.6%), and posterior parietal (7.3%) cortex. This implies that the disease process is bilateral even in those cases with clinically unilateral disease. This widely available technique may be useful in the early diagnosis of CBD and in differentiation from other extrapyramidal disorders.
Oculofacial‐skeletal myorhythmia in central nervous system Whipple's disease: Additional case and review of the literature
Authors: Simpson David A. , Wishnow Robin , Gargulinski Richard B. , Pawlak Anne M. 
Published: May 2005

AbstractA case of oculofacial‐skeletal myorhythmia associated with cerebral Whipple's disease is presented. This peculiar abnormal movement disorder consists of a convergent‐divergent pendular nystagmus associated with a synchronous, rhythmic movement of the mouth, jaw, and extremities. The movements in previous cases have responded inconsistently to a variety of broad‐spectrum antibiotic drugs, and antiepileptic, muscle relaxant, antispastic, and psychotropic drugs. The current patient's mental status improved after starting intravenous ceftriaxone but improvement of the abnormal movements occurred only after the addition of oral valproate. Current treatment consists of intravenous trimethoprim‐sulfamethoxazole for 2 weeks followed by oral trimethoprim‐sulfamethoxazole twice daily for 1 year. Presented here is an alternative treatment of intravenous ceftriazone followed by oral trimethoprim‐sulfamethoxazole in combination with valproate for abnormal movements not responsive to antibiotic drugs alone.
Bismuth subsalicylate toxicity as a cause of prolonged encephalopathy with myoclonus
Authors: Gordon Mark Forrest , Abrams Russell Ira , Rubin Daniel B. , Barr William B. , Correa Denise D. 
Published: May 2005

AbstractBismuth subsalicylate preparations are over‐the‐counter products for gastrointestinal complaints. Bismuth toxicity causes delirium, psychosis, ataxia, myoclonus, and seizures and is reversible over several weeks or months, when bismuth intake is stopped. We report a 54‐year‐old man with a 6‐week history of progressive confusion and memory difficulty and a 2–3‐week history of involuntary movements and gait impairment. His encephalopathy was further characterized by marked multifocal myoclonic jerks, coarse postural tremors, postural instability, and gait ataxia. He gradually improved. Extensive toxic, metabolic, and infectious workup demonstrated bismuth toxicity. Spinal tap and brain magnetic resonance scan were normal. Electroencephalography showed bihemispheric slowing. As his encephalopathy cleared, he reported using bismuth subsalicylate long term (daily intake of 8 oz). Bismuth levels 5 weeks after cessation of bismuth were elevated and normalized after 12 weeks. He followed a typical course for bismuth toxicity with subacute progressive encephalopathy and gradual recovery. Creutzfeldt‐Jakob was strongly considered due to his rapidly progressive encephalopathy, multifocal myoclonus, and ataxia. Due to its rarity, bismuth toxicity is often overlooked. We hope this presentation will increase recognition of bismuth toxicity. We believe more detailed labeling of bismuth products is needed to avoid similar toxicity from this readily available product.
Propriospinal myoclonus upon relaxation and drowsiness: A cause of severe insomnia
Authors: Montagna Pasquale , Provini Federica , Plazzi Giuseppe , Liguori Rocco , Lugaresi Elio 
Published: May 2005

AbstractThree patients, aged 71, 50, and 41 years, presented with myoclonic activity arising in the relaxation period preceding sleep onset and causing severe insomnia. Polygraphic studies showed that the myoclonic activity began in spinally innervated muscles, propagating at low speed to rostral and caudal muscular segments. Myoclonus arose whenever patients relaxed mentally and showed diffuse electroencephalographic alpha activity and was independent of posture. The jerks disappeared during sleep. Clonazepam afforded symptomatic improvement. Propriospinal myoclonus arising from a spinal generator may be facilitated by changes in supraspinal control related to vigilance levels. When arising during relaxation and drowsiness, it may cause severe insomnia.
A long‐term follow‐up study of cinnarizine‐ and flunarizine‐induced parkinsonism
Authors: Negrotti A. , Calzetti S. 
Published: May 2005

AbstractThe natural course of calcium‐entry blocker–induced parkinsonism was evaluated in 13 elderly patients previously exposed to cinnarizine or flunarizine or both for a median period of 7 months. Clinical assessments were carried out before drug discontinuation and twice thereafter over a period lasting ≤7 years. None of the patients showed a full recovery of extrapyramidal signs, indicating that the long‐term prognosis of the parkinsonism is less benign than previously reported. Two main patterns of clinical outcome were recognized (i.e., “remittent” and “persistent and not progressive”parkinsonism), whereas the development of a progressive disorder was observed only in one patient. No significant correlation was found between the patterns of outcome and some clinical variables, such as total duration of exposure to cinnarizine and flunarizine, cumulative drug dosages, and age at onset of parkinsonism. There was no significant difference in terms of family history of essential tremor or parkinsonism or both among the patients with the two main patterns of clinical course.