bluuebunny/crossref_metadata_2025 huggingface dataset:
Cabergoline in Parkinson's disease complicated by motor fluctuations
Authors: Geminiani Guiliano , Fetoni Vincenza , Genitrini Silvia , Giovannini Paolo , Tamma Filippo , Caraceni Tommaso
Published: December 2004

Cabergoline is a long‐acting D2 dopamine (DA) agonist. We conducted an open study to investigate the effectiveness and tolerability of cabergoline, administered once a day orally, in 50 consecutive patients with Parkinson's disease complicated by motor fluctuations and dyskinesias. In 15 patients cabergoline replaced another direct DA agonist. Evaluation after 6 months of treatment (also including patients who dropped out during this period), showed an improvement in off or on hours, or both, in excess of 50% in 27 patients, comprising 20 of the 35 patients (57%) previously untreated with DA agonists and seven of the 15 patients (47%) already on DA agonists when the study began. Of the 22 patients who received the treatment for 1 year, the improvement was maintained up to final evaluation in the patients not on DA agonists at admission (n = 16), whereas a slight deterioration in clinical condition was observed in the patients already on DA agonists at admission (n = 6). Only six patients showed a detectable increase in dyskinesias. The most common side effects were gastric upset (n = 12), orthostatic hypotension (n = 3), and ankle edema (n = 3), all mild; also observed were two cases of pleural effusion/pulmonary fibrosis. Twenty patients (40%) failed to complete the treatment; of these, five (10% of total) dropped out because of adverse effects. It is concluded that once‐daily administrations of cabergoline are useful for treating patients with Parkinson's disease with motor fluctuations and may advantageously substitute other DA agonists. The side effects of the drug are generally mild, although two cases involving pleuropulmonary complications did emerge.
Reversal of behavioural abnormalities by fetal allografts in a novel rat model of striatonigral degeneration
Authors: Wenning G. K. , Granata R. , Laboyrie P. M. , Quinn N. P. , Jenner P. , Marsden C. D.
Published: December 2004

We have developed a rodent model of striatonigral degeration, one of the core pathologies underlying the disease multiple system atrophy (MSA). 6‐Hydroxydopamine (6‐OHDA) was administered into the left medial forebrain bundle of male Wistar rats, followed 3–4 weeks later by intrastriatal injection of quinolinic acid into the ipsilateral stratum. The 6‐OHDA lesion resulted in ipsilateral rotation to (+)‐amphetamine and contralateral rotation to apomorphine. Following the subsequent striatal lesion, amphetamine‐induced ipsilateral rotation persisted, but apomorphine‐induced contralateral rotation was reduced or abolished. Subsequently, the lesioned striatum was implanted with fetal CNS allografts consisting of cell suspensions derived from striatal primordium alone or combined with cografts of ventral mesencephalon. Cografted rats showed a reduction or reversal of amphetamine‐induced rotation. This was not observed in animals receiving striatal grafts alone. Apomorphine‐induced contralateral rotation was restored after striatal grafts alone, but only partially in animals receiving sham or cografts. Tyrosine hydroxylase (TH) and dopamine‐ and cyclic adenosine 3′:5′‐monophosphate‐regulated phosphoprotein (DARPP 32) immunocytochemistry showed mesencephalic and striatal graft survival in most animals. However, dopaminergic outgrowth was restricted to the graft deposit. The latter was surrounded by a markedly gliotic glial fibrillary acidic protein‐positive capsule continuous with corpus callosum. Dopaminergic reinnervation of denervated and lesioned adult striatum itself was absent, suggesting that rotational recovery was due to diffuse dopamine release. The study shows that combined unilateral lesioning of rodent medial forebrain bundle and striatum results in a characterstic drug‐induced rotational response that can be partly restored by mesencephalic/striatal cografts.
Dentatorubral‐pallidoluysian atrophy. Clinical features of a five‐generation danish family
Authors: Nielsen J. E. , Sørensen S. A. , Hasholt L. , Nørremølle A.
Published: December 2004

We describe the first Danish family with dentatorubral‐pallidoluysian atrophy (DRPLA), containing 16 clinically affected individuals in five generations. Inheritance is autosomal dominant. The disorder was diagnosed as Huntington's (HD), but analysis of the IT15 gene for HD revealed normal alleles. The diagnosis of DRPLA was based on the finding of elongated CAG repeats in the B37 gene on chromosome 12 in affected individuals. The age at onset ranged from 13 to 60 years, with most severe clinical picture being associated with onset in childhood. Clinical features included varying combinations of dementia, euphoria, visuomotor disturbances, speech problems, ataxia, tremor, epilepsy, and involuntary movements presenting as chorea, athetosis, and dystonia. We discuss characteristics of DRPLA that may enable the differentiation from HD on a clinical basis. In conclusion, DRPLA should be considered and DNA analysis is recommended in patients manifesting varying combinations of extrapyramidal and cerebellar symptoms, especially when clinical features show pronounced intrafamilial variability, and dyscoordination, tremor, myoclonus, epilepsy, and euphoria are part of the syndrome.
Severe motor tics causing cervical myelopathy in Tourette's syndrome
Authors: Krauss Joachim K. , Jankovic Joseph
Published: December 2004

We describe two patients with Tourette's syndrome in whom severe motor tics involving the neck were complicated by cervical myelopathy. The first patients, a 21‐year‐old man, had complex tics consisting of violent twisting and extending movements of the neck preceded by an irresistible urge to produce the abnormal postures. Two years after onset of these tics, paraesthesias, sensory deficits up to the level of C4, and a gait disturbance developed. Neuroimaging studies confirmed compressive myelopathy, and the symptoms gradually improved with botulinum toxin injections in the posterior cervical muscles. The second patient, a 42‐year‐old man, had violent clonic tics consisting of thrusting head jerks. The repetitive flexion‐extension neck movements had been present since the age 10 years. At age 23, he developed progressive weakness off all four extremities and bladder and sexual dysfunction. Myelography demonstrated cervical spinal canal stenosis with retrospondylosis from C3 through C5 and a Klippel‐Feil malformation. After cervical decompression by, C3‐C5 laminectomies, his spinal cord symptoms improved temporarily. The tics, however, continued, and the neurologic deficits of cervical myelopathy progressed again after age 34. He did not benefit from a second operation. This report draws attention to the possibility that some tics can produce disabling compressive myelopathy. Early diagnosis and treatment of the movement disorder is essential in such cases.
Persisting “Writer's Cramp” as a result of compensation of a temporary palsy due to a hereditary neuropathy with liability to pressure palsies
Authors: Straube Andreas , Mai Norbert , Walther Ernst , Mayer Michael
Published: December 2004

A 49‐year‐old man reported several periods of acute paresis of different nerves after exposure to pressure. All palsies showed a good recovery over a period of days to months. The suspected diagnosis of a hereditary neuropathy with liability to pressure palsies was confirmed by the histology of a suralis nerve biopsy, which showed a distinct tomaculous swelling of the myelin. Nine years ago he noticed an acute, distally pronounced palsy of the right arm. A brachial plexus lesion was diagnosed. His profession required written work, thereby forcing him to compensate this weakness by increasign the coactivation of the elbow and upper arm. This coactivation persisted even after complete recovery from the plexus palsy. Thus, the patient showed the typical feature of classcal writer's cramp, with broad coactivation of the arm muscles, which has continued to the present. At the same time, however, the patient was able to perform other motoric tasks well, such as painting. After several practice sessions with a special program that makes use of preserved motor abilities to reestablish writing, the patient was again able to write with a normal kinematic profile as documented by the recorded handwriting. This suggests that the “writer's cramp” of our patient is one form of task‐related dystonia that may be related more to the perserveration of a misleading motor strategy than to a general inability of the motor system to control the movement properly.
Alleviation of experimental hemiparkinsonism by high‐frequency stimulation of the subthalamic nucleus in primates: A comparison with L‐dopa treatment
Authors: Benazzouz Abdelhamid , Boraud Thomas , Féger Jean , Burbaud Pierre , Bioulac Bernard , Gross Christian
Published: December 2004

Experimental studies in 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐treated monkeys have shown that akinesia and rigidity are linked to a hyperactivity of glutamatergic subthalamic nucleus neurons and that the lesion of this nucleus can ameliorate parkinsonian motor signs. In our study, high‐frequency stimulation applied at the subthalamic level was performed on two Macaca mulatta monkeys rendered hemiparkinsonian by unilateral infusion of MPTP. Its effects on rigidity and bradykinesia have been quantified. The results exhibit an important alleviation of both symptoms during the application of subthalamic stimulation comparable to that obtained during L‐Dopa treatment, but without the appearance of abnormal movements such hemiballism or dyskinesia. Our data show that subthalamic stimulation has a beneficial effect on experimental parkinsonian rigidity and bradykinesia and suggests a new therapy approach for the treatment of Parkinson's disease by using subthalamic high‐frequency stimulation instead of L‐Dopa treatment.
Clinical trial of piracetam in patients with myoclonus: Nationwide multiinstitution study in Japan
Authors: Ikeda Akio , Shibasaki Hiroshi , Tasgiro Kunio , Mizuno Yoshikuni , Kimura Jun
Published: December 2004

Sixty patients with disabling myoclonus excluding mainly spinal myoclonus were treated by piracetam as an open‐labeled study, and myoclonus score, neurological symptoms, functional disbility, and intensity of myoclonus were scored before and after treatment, including a blinded video inspection. Electrophysiological correlation also was investigated before and after treatment. Piracetam was effective in myoclonus, especially that of cortical origin, in both had positive benefits on gait ataxia and convulsions but not on dysarthria, and feeding and hand writing improved much significantly. Psychologically significant improvement was seen in decreased motivation, sleep distrubance, attention deficit, and depression, all of which might be possibly secondary benefits associated with improvement of myoclonus. There was no positive correlation between clinical and electrophysiological improvement. Tolerance was good, and side effects were transient. However, hematological abnormalities observed in at least two patients in the present study should be kept in mind when relatively large doses of piracetam are administered, especially in combination with other antimyoclonic drugs.
Subacute encephalomyelitis presenting as stiff‐person syndrome: Clinical, polygraphic, and pathologic correlations
Authors: Armon Carmel , Swanson Jerry W. , McLean John M. , Westbrook Philip R. , Okazaki Haruo , Kurtin Paul J. , Kalyan‐Raman Uma P. , Rodriguez Moses
Published: December 2004

A 60‐year‐old woman presented with stiff‐person syndrome (SPS). Treatment with diazepam controlled her painful spasms initially. Two and one‐half years after the onset of SPS, new spells of paroxysmal legjerking and apnea developed. A spell was recorded with simultaneous video and polygraphic techniques that revealed simultaneous firing of motor unit potentials in several muscles (paraspinal, internal hamstring, and abdominal muscles). Apnea was associated with arterial oxygen desaturation. An increase in the dose of diazepam decreased the number and severity of these episodes. Seventeen months later, the patient began to taper the diazepam dose. Shortly thereafter, she had a cardiorespiratory arrest and subsequently died. Autopsy showed small chronic inflammatory foci in the pancreas (some associated with islets) and findings of diffuse encephalomyelitis characterized by perivascular cuffing in the spinal cord, brainstem, thalamus, hippocampus, and amygdala and a dense mononuclear infiltrate in the anterior horns of the lumbar and cervical cord, with relative preservation of axons and myelin. Cell typing showed this infiltrate was polyclonal and reactive. There have been rare cases of SPS associated with encephalomyelitis reported previously. Although the prolonged course in our patient suggested that SPS may have preceded encephalomyelitis, the more likely explanation is that the patient had an unusually long course of encephalomyelitis alone.
Foot dystonia and lumbar canal stenosis
Authors: Blunt Stavia B. , Richards Peter G. , Khalil Nofal
Published: December 2004

We describe a patient who developed involuntary, painless, dystonic contraction of the toes of the right foot on standing or walking. The development of this abnormal movement had been preceded by sensory disturbance on the soles of both feet, triggered by dorsiflexion of the feet. Examination showed that weight bearing on the right foot and walking brought on clawing of the toes of the right foot, which was relieved within seconds of taking pressure off the right foot. There was sensory and reflex evidence of bilateral S1 root disturbance confirmed by electrophysiology. Magnetic resonance imaging of the lumbar spine showed marked stenosis of the lumbar canal with compression of the L5 and S1 nerve roots bilaterally. The patient underwent a lumbar laminectomy with nerve root exit foramina decompresion, which abolished the foot dystonia and has considerably improved the sensory disturbance. This case demonstrates that lumbar canal stenosis and/or nerve root compression, may be responsible for foot dystonia. Amelioration of the abnormal movement by surgical decompression argues strongly in favour of this hypothesis.
Imaging of dopamine receptors with [123I]iodobenzamide single‐photon emission–computed tomography in neuroleptic malignant syndrome
Authors: Jauss M. , Krack P. , Franz M. , Klett R. , Bauer R. , Gallhofer B. , Dorndorf W.
Published: December 2004

With the tracer [123I] iodobenzamide;([123I]‐IBZM), it is possible to image dopamine receptor occupancy with singlephoton emission‐computed tomography (SPECT). We report follow‐up examinations with IBZM‐SPECT in neuroleptic malignant syndrome (NMS) to display D2‐receptor availability in the acute phase and during the course of remission. A 27‐year‐old man was admitted with severe akinesia, rigor, tachycardia, fever, and elevated creatine phosphokinase level (CK) after neuroleptic medication. NMS was diagnosed, was started with dantrolene, amantadine, and dopamine agonists. IBZM‐SPECT examination was performed on days 6, 34, 90, 107, 131, and 201. In the acute state of NMS, there was no binding of IBZM to D2‐receptors. SPECT reached almost normal values on day 131, but clinical examination still showed a mild parkinsonian syndrome. With SPECT, the D2‐receptor occupancy in NMS could be successfully shown in correlation with extrapyramidal signs. IBZM‐SPECT may therefore serve to monitor D2‐receptor occupancy in patients at risk for NMS.
Paroxysmal kinesigenic dystonia associated with a medullary lesion
Authors: Riley David E.
Published: December 2004

A 67‐year‐old man experienced the abrupt onset of intermittent of intermittent spasms of tightening of his throat muscles and elevation of his tongue to the roof of his mouth. These were precipitated by initiating movements, either of his mouth (eating, drinking, speaking, yawning) or of his whole body (arising from bed or a chair, lifting heavy weights). Episodes occurred six to 20 times per day, lasted 10–30 s, then resolved spontaneously. Two years later, results of his general neurological examination including speech, were normal. Several spasms were provoked by arising from a seated or supine position or by drinking. Objectively, there was a strained dysphonia accompainied by palpable hardening of the supralaryngeal muscles. Each episode resolved within 15s. Magnetic resonance imaging (MRI) showed evidence of a remote hemorrhage in the medulla. No abnormal blood vessels were seen. Phenytoin 300 mg/day abolished the spasms within days. Decreasing the dose to 200 mg/day months later led to a partial return of symptoms. Relief has persisted for 3 years. This patient has paroxysmal kinesigenic dystonia (PKD) of structures (pharynx, larynx tongue,) innervated by lower cranial motor nerves and a medullar lesion on MRI. PKD has been associated with focal lesions at all levels of the central nervous system (CNS), although never before in the medulla. PKD seems to be a nonspecific phenomenon of the CNS in reaction to injury.
Nuclear spin relaxation study of aqueous raffinose solution in the presence of a gadolinium contrast agent
Authors: Ghalebani Leila , Kruk Danuta , Kowalewski Jozef
Published: December 2004

Paramagnetic enhancement of nuclear spin–lattice relaxation rates (PREs) was measured in aqueous solution of the trisaccharide raffinose in the presence of a gadolinium(III) complex, GdDTPA–BMA, used as a magnetic resonance imaging contrast agent. The relaxation enhancement of aqueous protons was measured over a broad range of magnetic fields, using field‐cycling apparatus in addition to conventional spectrometers. The nuclear magnetic relaxation dispersion profile thus obtained was interpreted with a recently developed model, allowing for both inner‐ and outer‐sphere relaxation. The relaxation enhancement for the carbon‐13 nuclei in raffinose was studied under high‐resolution conditions at three magnetic fields, whereas the sugar proton PRE was measured at two fields. The PRE of the sugar nuclei could be interpreted in a consistent way, assuming that it was caused by the outer‐sphere mechanism. The electron spin relaxation was found to be a less important source of modulation of the electron–nuclear dipole–dipole interaction than the mutual translational diffusion. Copyright © 2004 John Wiley & Sons, Ltd.
Ring current effects on nuclear magnetic shielding of carbon in the benzene molecule
Authors: Ferraro M. B. , Faglioni F. , Ligabue A. , Pelloni S. , Lazzeretti P.
Published: December 2004

The differential Biot–Savart law of classical electrodynamics was applied to develop a ring current model for the magnetic shielding of the carbon nucleus in benzene. It is shown that the local effect of the π currents, induced by a magnetic field normal to the molecular plane, on the $\sigma_{\|}^{\rm C}$ out‐of‐plane shielding tensor component vanishes. However, approximately 10% of $\sigma_{\|}^{\rm C}$ is due to the shielding contributions from π current density in the region of the other carbon atoms. Magnetic shielding density maps obtained via quantum mechanical procedures confirm the predictions of the classical model. Copyright © 2004 John Wiley & Sons, Ltd.
Antioxidant status decreases in children with acute lymphoblastic leukemia during the first six months of chemotherapy treatment
Authors: Kennedy Deborah D. , Ladas Elena J. , Rheingold Susan R. , Blumberg Jeffrey , Kelly Kara M.
Published: December 2004

Background

Children undergoing treatment for acute lymphoblastic leukemia (ALL) receive combination chemotherapy and many of the components are associated with free radical production.

Procedure

Among 103 children newly diagnosed with ALL, plasma concentrations of antioxidants, total antioxidant capacity (ORAC), and DNA oxidized base 8‐oxodeoxyguanosine (8‐oxo‐dG) were analyzed at baseline and 3 and 6 months after diagnosis.

Results

Plasma vitamin A, antioxidants, 8‐oxo‐dG, and ORAC changed from diagnosis through the first 6 months of ALL therapy. In patients with higher plasma concentrations of vitamin A, E, total carotenoids, ORAC, and 8‐oxo‐dG there was a beneficial association with fewer dose reductions, fewer infections, improved quality of life, less delay in chemotherapy treatment schedule, reduced toxicity, and fewer days spent in the hospital. There were also adverse relationships demonstrated.

Conclusions

Among children with ALL, antioxidant levels and oxidative stress appear to be associated with duration and complications of treatment. © 2004 Wiley‐Liss, Inc.
Thermophysical properties of anhydride‐cured epoxy/nano‐clay composites
Authors: Miyagawa Hiroaki , Rich Michael J. , Drzal Lawrence T.
Published: December 2004

Polymer nano‐composites made with a matrix of anhydride‐cured diglycidyl ether of bisphenol A (DGEBA) and reinforced with organo‐montmorillonite clay were investigated. A sonication technique was used to process the epoxy/clay nano‐composites. The thermal properties of the nano‐composites were measured with dynamic mechanical analysis (DMA). The glass transition temperature Tg of the anhydride‐cured epoxy was higher than the room temperature (RT). For samples with 6.25 wt% (4.0 vol%) of clay, the storage modulus at 30°C and at (Tg + 15)°C was observed to increase 43% and 230%, respectively, relative to the value of unfilled epoxy. The clay reinforcing effect was evaluated using the Tandon‐Weng model for randomly oriented particulate filled composites. Transmission electron microscopy (TEM) examination of the nano‐composites prepared by sonication of clays in acetone showed well‐dispersed platelets in the nano‐composites. The clay nano‐platelets were observed to be well‐intercalated/expanded in the anhydride‐cured epoxy resin system. POLYM. COMPOS., 26:42–51, 2005. © 2004 Society of Plastics Engineers.
Changes in prescribing of inhaled corticosteroids (1999–2002) in Scotland
Authors: Boyter Anne C. , Steinke Douglas T.
Published: December 2004

Purpose

To investigate the trend in prescribing of inhaled corticosteroids and general practitioner (GP) consultations for respiratory diseases.

Methods

A longitudinal observation study of all prescriptions, from primary care, for inhaled corticosteroids dispensed in Scotland from January 1999 to May 2002 was undertaken.

The main outcome measures were the trends in prescribing of inhaled corticosteroids and GP consultations for respiratory diseases.

Results and conclusions

The prescribing of all inhaled corticosteroids has risen over the study period. The rise in prescribing of the combination product containing fluticasone and salmeterol appears not to have been at the expense of the prescribing of fluticasone alone while the prescribing of the budesonide/eformoterol combination may be at the expense of budesonide (BUD) alone. GP consultations for both asthma and chronic obstructive pulmonary disease (COPD) have declined over a similar period.

The increased prescribing of inhaled corticosteroids over this period is associated with the increased use of the fluticasone/salmeterol combination rather than an increase in the use of all inhaled corticosteroids. The accompanying fall in number of consultations with GPs may be due to this increased prescribing or a move to nurse led clinics. Copyright © 2004 John Wiley & Sons, Ltd.
Thermomechanical studies of amorphous and crystalline polymers
Authors: Sidorovich A. V. , Kushinsky E. V.
Published: December 2004

Translated from: Vysokomolekuliarnye Soedineniia 2, 778–84 (May 1960). A thermomechanical study was made of the softening of crystalline polymers during uniform, uniaxial stretch and also of the effect of the rate of heating upon the softening or amorphous polymers. The effect of the tensile force on the thermo‐mechanical behavior of various polymers was measured over the range 20 to 100 kg/cm2 and within wide temperature limits (−150° to 250°C). Ribbons 50 mm long, 2‐4 mm wide and 0.05 to 0.5 mm thick served as specimens.
Ultraviolet degradation of plastics and the use of protective ultraviolet absorbers
Authors: Hirt R. C. , Searle N. Z. , Schmitt R. G.
Published: December 2004

The degradation of plastics by ultraviolet energy and the use of protective ultraviolet absorbers to improve stability necessitate studies along several lines. These include (a) the measurement of the ultraviolet spectral energy distribution of sunlight and of the indoor accelerated test sources, (b) the measurement of the extent of degradation as a function of the wavelength of the incident radiation, (c) an estimate of the absorbing effectiveness of the added protective agents, and (d) the stability of the protective ultraviolet absorbers themselves.
The effect of molecular weight distribution on the flow properties of polyethylene
Authors: Mills D. R. , Moore G. E. , Pugh D. W.
Published: December 2004

The non‐Newtonian flow behavior of polyethylene has been investigated with respect to the effects of molecular weight and molecular weight distribution. Effects of die geometry on melt fracture as well as preliminary extrudate orientation studies are discussed.
The effect of extrusion variables on the fundamental properties of tubular polythene film
Authors: Huck N. D. , Clegg P. L.
Published: December 2004

The mechanism of formation of tubular polythene film is a complicated process, and extensive studies have shown that the properties of the film made are influenced profoundly and in a complex way both by the processing conditions used by certain design features of the equipment. Studies of the effect of the extrusion variables on the more important film properties, both optical and mechanical, are reviewed in this paper. The results are discussed in terms of the fundamental nature of polythene film, its surface, its crystalline structure and its orientation.
Inorganic‐organic high polymers, phenoxyaldehyde resins of Titanium (IV) and Hafnium (IV)
Authors: Landry R. J. , Bartel E. H.
Published: December 2004

A new series of inorganic‐organic high polymers have been synthesized namely; the metaloxene polymers of phenolaldehyde. Titanium (IV), Zirconium (IV) and Hafnium (IV) phenolaldehyde have been prepared and other metals especially the refractory type metals may merit further development as calorobic plastic materials. The hafnium resin has been compression molded into a rocket‐nozzle insert shape with satisfactory rocket‐firing results.
The thermodynamics of biaxial elongation
Authors: Stein Richard S.
Published: December 2004

If temperature variations of forces in both directions are observed simultaneously at constant simple dimensions, internal energy and entropy changes on elongation in those directions may be calculated at constant volume and in the more common experimental condition of constant pressure. Thermodynamic derivatives at constant volume are important for fundamental molecular interpretation being related to configuration change. Constant pressure quantities were therefore changed into constant volume ones by the use of an evaluated correction term, involving average Young Moduli and thermal expansion coefficient.
Polymers as conductors and semi‐conductors
Authors: Atlas S. M. , Becher M. , Mark H. F.
Published: December 2004

Mobile ions can be introduced thereby increasing the conductivity, with a limiting operating temperature range of 200°–250°C. Conductivity can be increased with the formation of conjugatd double bonds. Polymeric compounds may be synthesized with metallocyclic groups, where an atom of metal is bound to nitrogen atoms in a heterocyclic system in the basic chain of conjugation of the macromolecule. Here phtalocyanimes possess the greatest thermal stability. Lastly there are semiconducting polymers with conjugated double bonds containing hetero‐atoms in the principle chain, having unpaired electrons of oxygen and nitrogen.
Physical techniques used in studying interfacial phenomena
Authors: Patrick Robert L.
Published: December 2004

Adsorption studies on powdered and planar surfaces yield significant information regarding the rate and degree of interaction between the substrate and the organic adsorbate. Investigative tools include contact angle measurement, radiotracer methods, ellipsometry, x‐ray diffraction, electron diffraction, elegant infrared techniques, dynamic desorption techniques, and film balance applications.
The effect of polymerization catalysts on the rate of degradation of isotactic polypropylene
Authors: Ryshavy D. , Balaban L.
Published: December 2004

One of the reasons for purification of low‐pressure polymerization products is the assumed degradation effects of retained catalysts. Degree of degradation was determined from the change in viscosity number. Effects of catalysts on active sights and deactivation were noted along with degradation in the presence of air and oxygen in addition to determining, the effect of antioxidants. Individual components of the catalyst may have the ability to intensify the effect of any antioxidant and affect the rate of degradation where catalyst influence was better defined in the presence of oxygen.
Bibliography on ultraviolet degradation and stabilization of plastics
Authors: Searle N. Z. , Hirt R. C.
Published: December 2004

A bibliography of references from 1957 through 1960 was prepared containing the following sub‐headings: Protective Ultraviolet Absorbers, Light Sources, Light Fastness Evaluation, Plastics Degradation and Stabilization Polyesters, Polystyrene, Polyvinylchloride, Polyethylene, Polyacrylo and Methacrylonitrile, Polymethyl Methacrylate, Cellulose Acetate and Nitrate, Polyvinyl alcohol, Polyamides, Wool, Rubber, Silicone Resin, Wood, Dyes and Paint Films, Epoxy, Melamine and Urea Formaldehyde, Oil Films, General Mechanical Degradation, Free Radicals and ESR, Photochemistry, Photochemistry and Spectroscopy at Low Temperatures, Antioxidants and Free Radical Scavengers, Flash Photolysis, Energy Transfer, Phosphorence and the Triplet State, Fluorescence.
Dynamic elastic behavior or high polymers at audiofrequencies
Authors: Sauer J. A.
Published: December 2004

A brief description is given of the use of a resonant‐bar type apparatus for measurement of the dynamic elastic modulus and the associated damping or internal friction of a solid polymer. Each different type of polymer is found to exhibit a characteristic internal friction spectrum when explored over the temperature range from liquid nitrogen temperatures to the melting point. These spectra are characterized by the occurrence of one or more peaks in the mechanical loss data centered about certain temperatures, accompanied by an associated drop in dynamic modulus. By variation of polymer composition and of polymer structure, by addition of low molecular weight compounds, and by subjection of samples to irradiation, considerable additional information can be gained that would be helpful in determining the nature of the molecular mechanisms that are responsible for the observed transitions. Dynamic mechanical data are presented and discussed for a series of poly(alpha olefins) with methyl, ethyl, propyl, isopropyl and isobutyl side chains to depict the effects of crystallinity, side chain length and side chain structure on the observed transitions.
Dynamic shear behavior of high polymers at low frequencies
Authors: Sinnott K. M.
Published: December 2004

The experimental techniques used to measure the dynamic shear behaviour of polymers at low frequencies, that is below 10 sec−1, are discussed with particular reference to the torsion pendulum. The various types of relaxations which can occur in amorphous and semicrystalline polymers are considered. Polymethyl methacrylate, polyethyl methacrylate, and polystyrene are examples of amorphous polymers. The effects of crosslinking, intermolecular forces, steric effects, and plasticizers on the main glass transition of other amorphous polymers are also described. Polytetrafluorethylene is an example of a linear, semi‐crystalline polymer. The effect of introducing trifluoromethyl groups along the chain in copolymers of tetrafluoroethylene and hexafluoropropylene is described. Results obtained with polypropylene are also discussed.
Creep of high polymers
Authors: Williams Malcolm L. , Howard William H.
Published: December 2004

For polymers the isothermal creep compliance shows a major dispersion region from the glassy compliance Jg to the quasi‐equilibrium compliance Je. Further increases in compliance are associated with viscous flow. There is no detailed molecular mechanism to explain these phenomena although the modified Rouse theory and the postulated entanglement coupling present a reasonable physical concept. To empirically describe the creep curves of polycrystalline metals, a power law (\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document} = mt−n) has frequently been used, where \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document} is the creep rate, t is the time and m and n are constants with O⩽n⩽. In particular, n equal to 2/3 leads to Andrade creep, a relationship which is applicable to both polymers and metals. A comparison of the creep behavior of polymers and polycrystalline metals shows many points of similarity.
Novel polymerization methods. Introduction
Authors: Werber F. X.
Published: December 2004

New methods, new structures leading to novel properties are presented in a collection of summaries. Areas discussed were: thiosemicarbazides, organometallic initiation of allene polymerization, poly(1,1,4,4,‐tetramethyl‐1,3‐butadiene), emulsion polymerization of vinyl acetate with protein detergent solubilizing agents, alkali metal organic catalysts for stereospecific polymerization, anionic polymerization of dienes, rate constants in anionic polymerization, a series on polymerization by oxidative coupling with amine copper salt catalysts, block polymerization by vapor phase swelling, intra‐intermolecular propagation in the solid‐state and radiation induced polymerization.
Turbidimetric determination of the molecular weight distribution of linear polyethylene
Authors: Taylor W. C. , Tung L. H.
Published: December 2004

α‐Chloronaphthalene plus 30 weight percent of dimethylphthalate was the solvent with 0.5% ethyl cellulose as stabilizer. A polymer concentration of 0.0025% gave optimum results. A parameter S which is defined as the difference in temperature between 20% and 50% of the total reduction in phototube output is related linearly to a parameter of the Wesslau distribution.
Identification of the urethane‐epoxy reaction product
Authors: Wood R. N.
Published: December 2004

The probable molecular structure resulting from a reaction of equal parts of a Bisphenol A/Epichlorohydrin epoxy and a Tolylene Diisocyanate Prepolymer with a selected diamine has been identified by using spectrometry. This identification presents additional opportunities for attaching other complex molecules to either of the basic resins. Not only can this technique lead to an interesting family of hybrid plastics, but it is another step toward designing specific molecules for specific applications.
Pyrolysis of phenolic polymers
Authors: Anderson Hugh C.
Published: December 2004

The technique of thermogravimetry was used to investigate the thermal decomposition characteristics of several cross‐linked phenolic polymers, which included regular and chlorinated phenolics and phenolics copolymerized with silane, nylon and phenol‐furfural resins. These polymers were found to be more stable thermally than the usual polyester and epoxide polymers, as evidenced by slower rates of decomposition and lower ultimate percentage weight losses. Temperatures at which 50% of ultimate percentage weight losses occurred ranged from 395°C for a phenolic copolymerized with a silane to 505°C for a chlorinated phenolic copolymerized with a silane. Chemical modification of the regular phenolic cross‐linked structure caused a decrease in thermal stability.
Some effects of molecular weight distribution on the melt rheology of high density polyethylene
Authors: Wagner H. L. , Wissbrun K. F.
Published: December 2004

Using a high shear rate capillary viscometer, the melt viscosities of a series of high density linear polyethylenes ranging in weight average molecular weight from 70,000 to 160,000 have been measured from shear rates of 2 to 200 sec−1 and from 190° to 240°C. The data, corrected for elastic end effects are described by an empirical relationship except for the temperature term which is fitted to the Williams‐Landel‐Ferry equation. Over the range measured the viscosity is given approximately by a power law in relation to shear rate with an exponent dependent upon molecular weight.

The effects of distribution were examined by measuring the viscosity‐shear rate relationships for not only the above series, which varied in Mw/Mn from 23 to 10, but also for blends of polyethylenes of varying molecular weights or of fractions, and other polyethylenes obtained by removal of the high molecular weight tail. In general, the broader the distribution, the more sensitive is the viscosity to the rate of shear.

The end correction, a measure of the elastic energy, does not vary much with shear stress or temperature in the case of high density polyethylene.
The analysis of polymers for moisture and volatiles
Authors: David D. J. , Baumann G. F. , Steingiser Samuel
Published: December 2004

An analytical method for the quantitative determination of the moisture and volatile content of polymeric materials is described. The method has been applied to polycarbonates, urethane elastomers and polyesters. It has been found particularly valuable for moisture determinations of polymers which have limited solubility in most common solvents and for polymers whose moisture content is in the range of 0.001%‐0.01%. The moisture is expelled from the sample by means of heating under vacuum and collected in a cold trap. The vapor pressure of the water is then measured and correlated with the amount present in the sample. Volatiles, if present, can be determined by difference after removal of the water. Commercially obtainable equipment is employed.
Photoelastic phenomena in plastics during impact
Authors: Hall N. W. , Wright R. E. , Smith W. C.
Published: December 2004

The study of strain patterns in deformed, transparent plastic placed between crossed Polaroids can shed considerable light on the responses of these plastics to stress. This article describes a study of the differing responses of three thermoplastics of varying degrees of toughness to the notched Izod impact test. The growth and waning of the strain patterns during impact are followed by means of high‐speed cinematography; interpretation of the phenomena thus observed is aided by thin section microscopy of partially deformed specimens.
Cellular materials–composition, cell‐size, thermal conductivity
Authors: Guenther Frederick O.
Published: December 2004

Composition by weight and volume of a cellular material and how it changes with density is shown in the form of equations. The equations are used to derive the basic relationship between cell size, cell wall thickness, density of cellular material and density of solid and gaseous components. A simplified equation is presented for thermal conductivity of low density cellular materials. It is used to illustrate the contribution of the solid and gaseous components in cellular polystyrene and urethane at various densities. The contribution of factors other than conduction to observed thermal conductivity of cellular polystyrene is compared to that reported for fiber glass insulation. The observed effect of cell size on conductivity is presented and compared to the calculated effect, based on an equation in the literature.
Experimental measurement of roll‐separating forces during milling of plastics
Authors: Carey R. H.
Published: December 2004

A “milling viscosity” test has been developed which measures the roll‐separating forces encountered during milling of experimental compound formulations on a carefully set‐up and controlled laboratory two‐roll mill. A small 8‐in. x 16‐in. laboratory mill was equipped with force‐measuring dynamometers and used to explore the actions of different vinyl‐resin compounds. The instrument has proven to be useful in developing thermoplastic materials, in providing an index for predicting the tendency of a material to deflect calender rolls, and as an aid in estimating the forces which may be encountered in full‐size equipment.
Polymer analysis, using gas chromatographic separation of pyrolyzates on a capacity column
Authors: Stanley C. W. , Peterson W. R.
Published: December 2004

An analytical method for polymer mixtures has been developed, using gas chromatographic separation of pyrolysis products on a capillary column. This technique uses one set of column conditions for the analysis of a number of polymers, including those from methyl methacrylate, ethyl acrylate, 2‐ethylhexyl acrylate, butadiene, acrylonitrile, vinyl acetate, and styrene, either as homopolymers on as copolymers of two or more components.
A compound pendulum for dynamic viscoelastic property measurements
Authors: Rosenthal L. A. , Ungermah A. J.
Published: December 2004

A compound pendulum system has been developed for the measurement and study of the modulus of elasticity and internal damping properties of a viscoelastic specimen through a range of temperatures.

An analysis of the apparatus and the essential describing equations are presented. Test results for several materials are presented. In the region of the heat distortion temperature many materials exhibit a sharp peak in their damping characteristics. The modulus of elasticity drops rapidly in this region. Modulus of elasticity results obtained compare favorably with static testing machine data. The compound pendulum system described provides a simple technique for these physical property determinations continuously over a range of temperatures.
The nature, origin and effects of internal stresses in reinforced plastic laminates
Authors: Matta J. A. , Outwater J. O.
Published: December 2004

There is a tension set up between the resin and the glass upon curing. A simple experiment has been devised to measure this tension and to note how it changes with time and temperature. It is found that it does not diminish with time and that it is linearly dependent on the highest temperature to which the resin has been brought during or after cure. NOL‐type rings were made with the same resin systems and subjected to different cure temperature so that the effect of the different shrinkage tensions on the physical properties be examined.
The bonding of fillers to thermosetting resins
Authors: Vanderbilt Byron M. , Jaruzelski John J.
Published: December 2004

Use of silica was emphasized since it is available in high purity, and since it is a major ingredient in all glass fibers. Other fillers employed include the aluminas, silicates, glass, and simple salts. When using a hydrocarbon type thermosetting resin and no chemical coupling agent, all fillers were substantially equivalent from the standpoint of strength of moldings. When using a vinyl silanol type coupling agent in the mix, there was a vast difference, however. Silica and alumina are strongly coupled via the silanol linkage of the silane, the glasses and complex silicates such as clays are intermediate, and simple salts such as carbonates and sulfates do not respond at all.
Moldability of plastics based on melt rheology. Part 1—theoretical development
Authors: Weir F. E.
Published: December 2004

An expression for the “average” viscosity of a polymeric material realized during an injection molding shot is developed. From this expression certain rheological quantities are taken which should better express ease of molding than do conventional testing methods. Comparison is made between actual molding experience and quality as predicted by the new method.
Moldability of plastics based on melt rheology. Part II—practical applications
Authors: Weir F. E. , Doyle M. E. , Norton D. G.
Published: December 2004

An expression for the “average” viscosity of a polymeric material realized during an injection molding shot is developed. From this expression certain rheological quantities are taken which should better express ease of molding than do conventional testing methods. Comparison is made between actual molding experience and quality as predicted by the new method.
The relationship between optical exaltation and polymerizability of olefins. Correlation of exaltation with copolymerization
Authors: Downey Paul M. , Butler George B.
Published: December 2004

Monomers for which the necessary information was obtained for comparison included the following: styrene, α‐methylstyrene, cis and trans‐propenylbenzene, allylbenzene, m‐methylstyrene, p‐methylstyrene, o‐, m‐, and p‐chlorostyrene, 2,3‐, 2,4‐, 2,5‐, 2,6‐, 3,4‐, and 3,5‐dichlorostyrene, p‐ethylstyrene, and p‐tert‐butylstyrene. In both free radical and ionic copolymerizations involving similar monomers, plots of the logarithms of the relative reactivities of several substituted styrenes toward the styrene and methyl methacrylate radicals versus the differences existing between the exaltations of substituted styrenes and the exaltation of styrene were strikingly similar to those in which Hammett's sigma values for the styrene substituents were plotted against the relative reactivities of the substituted styrenes.
The polymerization and long‐term stability of room temperature curing epoxy resins
Authors: Steele Doris V.
Published: December 2004

The effect of resin mass on the degree of crosslinking during the initial polymerization of three typical polymer compounds was determined by electrical resistivity techniques. Activation energies for the electrical conduction process (Ec) were calculated and used as an index of the extent of additional crosslinking occurring during sixteen months of storage. Test data show continued polymerization at slow rates for periods of time ranging from three days to over sixteen months before the polymerization process is completed. The final degree of crosslinking is shown to be dependent on the extent of initial crosslinking.
Polymerization of methacryloyl chloride in selected solvents
Authors: Blatz Paul E.
Published: December 2004

Methacryloyl chloride was polymerized in a number of solvents, and the polyacid chloride was converted into the methyl ester. The yield and viscometric molecular weight are given for each sample, whereas the osmometric molecular weight is given for selected samples. The choice of solvent controls the degree of polymerization between the limits of 500 and 8,800. Polymer yields were about 20% and the degree of polymerization was 1500 when dioxane was used as a solvent, whereas the yield increased to 45% and the DP was very high when such solvents as cyclohexane and n‐hexane were used. Polymerization in solvent mixtures gave intermediate molecular weight values. Infrared analysis showed the presence of anhydride.
Microencapsulation by interfacial polycondensation
Authors: Mackinney Herbert W.
Published: December 2004

A water immiscible liquid is encapsulated in a thin skin of an insoluble copolymer by dissolving a difunctional acid chloride in said liquid and spraying the solution in fine droplets into a dilute aqueous solution of excess glycol or diamine. The polymer, which is not hygroscopic, forms as an insoluble film on the periphery of each drop. The microcapsules may be separated from the aqueous phase and dried without coalescing. Dyes, pigments, stabilizers, and other materials may be incorporated within the capsules.