bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Counter‐Current Chromatography: Instrumentation, Solvent Selection and Some Recent Applications to Natural Product Purification
Authors: FOUCAULT A. P. , CHEVOLOT L.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Vibrational Spectroscopy with Neutrons
Authors: JOBIC H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: IR Characterization of Metal Catalysts Using CO as Probe Molecule
Authors: MAUGE F. , BINET C. , LAVALLEY J. C.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Three Triterpenes (I) ‐ (III) and a Triterpene Ferulate (IV) from Rhoiptelea chiliantha.
Authors: JIANG Z.‐H. , INUTSUKA C. , TANAKA T. , KOUNO I.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: First Synthesis of a C‐Glycoside Analogue of a Tumor‐Associated Carbohydrate Antigen Employing Samarium Diiodide Promoted C‐Glycosylation.
Authors: URBAN D. , SKRYDSTRUP T. , BEAU J.‐M.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Novel Amphiphilic Cyclodextrins: Per[6‐deoxy‐6‐(4,5‐dicarboxy‐1,2,3‐triazol‐1‐yl)‐2,3‐di‐O‐methyl] Derivatives
Authors: KRAUS T. , BUDESINSKY M. , ZAVADA J.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: New Effective Synthesis of (N‐Acetyl‐ and N‐Stearoyl‐2‐amino‐2‐deoxy‐β‐D‐glucopyranosyl)‐ (1→4)‐N‐acetylnormuramoyl‐L‐2‐aminobutanoyl‐D‐isoglutamine, Analogues of GMDP with Immunopotentiating Activity.
Authors: LEDVINA M. , ZYKA D. , JEZEK J. , TRNKA T. , SAMAN D.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Serotonergic Ergoline Derivatives.
Authors: MANTEGANI S. , BRAMBILLA E. , CACCIA C. , DAMIANI G. , FORNARETTO M. G. , MCARTHUR R. A. , VARASI M.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Palau′amine and Its Congeners: A Family of Bioactive Bisguanidines from the Marine Sponge Stylotella aurantium.
Authors: KINNEL R. B. , GEHRKEN H.‐P. , SWALI R. , SKOROPOWSKI G. , SCHER P. J.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of (.+‐.)‐2′,3′‐Dideoxy‐3′‐fluoroapiosylpyrimidine Nucleosides.
Authors: AHN S. K. , KIM D. , SON H. J. , JEONG B. S. , HONG R. K. , KIM B. Y. , KIM E. N. , CHUNG K. H. , KIM J. W.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Anti‐HIV Properties of 1,2,4,6‐Thiatriazin‐3‐one 1,1‐Dioxide Nucleosides.
Authors: OCHOA C. , PROVENCIO R. , JIMENO M. L. , BALZARINI J. , DE CLERCQ E.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Effect of Acridine with Various Linker Arms Attached to C5 Position of 2′‐Deoxyuridine on the Stability of DNA/DNA and DNA/RNA Duplexes.
Authors: OZAKI H. , OGAWA Y. , MINE M. , SAWAI H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Triplex Forming Properties of an Acyclic N7‐Glycosylated Guanine Nucleoside.
Authors: CLAIR A. ST. , XIANG G. , MCLAUGHLIN L. W.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Genistein Complexes with Amines: Structure and Properties
Authors: MAZUREK A. P. , ET AL. ET AL.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Acetogenins of Annonaceae. Part 65. Glaucabellin and Glaucaflorin, Two Acetogenins from Annona glauca.
Authors: WAECHTER A.‐I. , SZLOSEK M. , HOCQUEMILLER R. , LAURENS A. , CAVE A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Convenient Synthesis of 1‐Phenylheptane‐1,5‐dione.
Authors: HASSARAJANI S. A. , DHOTARE B. , CHATTOPADHYAY A. , MAMDAPUR V. R.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: New β‐Lactam Derivatives: Synthesis and Antibacterial Activity of Mono Aryloxy‐s‐triazine Derivatives of Penicillin (V), Cephalosporin (IX), Ampicillin (VII), and Cephalexin (XI).
Authors: SHELAR A. R. , ADURE A. S. , SHELAR M. A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Unusual Bioactive Annonaceous Acetogenins from Goniothalamus giganteus.
Authors: ALALI F. Q. , ROGERS L. , ZHANG Y. , MCLAUGHLIN J. L.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Biological Activities of 5H‐Furo[3,2‐g][1]benzopyran‐5‐one Derivatives.
Authors: MIKY J. A. A. , SHARAF H. H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Absolute Measurements of the High‐Frequency Magnetic Dynamics in High‐Tc Superconductors
Authors: HAYDEN S. M. , AEPPLI G. , DAI P. , MOOK H. A. , PERRING T. G. , CHEONG S.‐W. , FISK Z. , DOGAN F. , MASON T. E.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Electron Transfer Reactions of Nickel(III) and Nickel(IV) Complexes
Authors: BHATTACHARYA S. , SAHA B. , DUTTA A. , BANERJEE P.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Survey of Ligand Field Parameters of Strong Field d5 Complexes Obtained from the g Matrix
Authors: MCGARVEY B. R.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Structural Aspects of Metal—Amide Complexes
Authors: CLEMENT O. , RAPKO B. M. , HAY B. P.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Transformations of 1,2,4‐Triazines under the Action of C‐Nucleophiles
Authors: RUSINOV V. L. , CHUPAKHIN O. N.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Phthalocyanines and Related Compounds: Subunits for the Preparation of Molecular Materials
Authors: GARCIA J. , GONZALEZ A. , GOULOUMIS A. , MAYA E. M. , PEREZ M. D. , REY B. D. , VAZQUEZ P. , TORRES T.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: C60′s Smallest Cousin
Authors: HEATH J. R.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Novel Nucleoside Analogues for the Therapy of Virus Disease: An Overview
Authors: HILGEROTH A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Endogenous Tetrahydroisoquinoline Alkaloids (TIQ′s): A Starting Point to Understand Alcoholism
Authors: MELZIG M. F. , HABER H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Radiation‐Chemical Degradation of Cellulose and Other Polysaccharides
Authors: ERSHOV B. G.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Biomimetic Alkane Oxidation Involving Metal Complexes
Authors: KARASEVICH E. I. , KULIKOVA V. S. , SHILOV A. E. , SHTEINMAN A. A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Reactions of Organic Peroxides
Authors: BAJ S. , CHROBOK A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Dirhodium(II) Tetrakis(methyl pyrrolidone‐5‐carboxylate) [Rh2(5R‐mepy)4 and Rh2(5S‐mepy)4] and Related Chiral Rhodium Catalysts
Authors: PODLECH J.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Metal Complexes with Biologically Important Ligands. Part 100. Bioorganometallic Chemistry—Transition Metal Complexes with α‐Amino Acids and Peptides
Authors: SEVERIN K. , BERGS R. , BECK W.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Separation of proteins from olive oil by CE: An approximation to the differentiation of monovarietal olive oils
Authors: Montealegre Cristina , Marina María Luisa , García‐Ruiz Carmen
Published: June 2010

The separation of proteins from olive oils by CE has been achieved for the first time in this work. Based on the protein profiles obtained using UV detection, a novel approach has also been proposed enabling the differentiation of monovarietal olive oils. An extraction procedure based on the precipitation of proteins in cold acetone and their isolation and solubilization in a hydro‐organic medium prior to their in‐capillary preconcentration in CE was a critical step in method development since proteins are minor components of olive oils. Then, a CE separation using a basic medium in a dynamically coated capillary originated electrophoretic profiles with multiple peaks from which seven of them were identified as proteins. When different monovarietal olive oils were injected, three different regions (zones I, II, and III) were identified. Zone III, called as differential zone, enabled to distinguish easily between extra virgin olive oils made from the Arbequina variety and the Picual and Hojiblanca varieties. This is the first time that protein profiles have been employed for the differentiation of botanical varieties of olive oils showing an enormous potential as traceability markers for these highly appreciated oils.
HPLC/CE‐ESI‐TOF‐MS methods for the characterization of polyphenols in almond‐skin extracts
Authors: Arráez‐Román David , Fu Shaoping , Sawalha Saleh M. S. , Segura‐Carretero Antonio , Fernández‐Gutiérrez Alberto
Published: June 2010

We have developed two rapid methods using CE and HPLC coupled to ESI‐TOF‐MS and both these methods have been compared for the separation and characterization of antioxidant phenolic compounds in almond‐skin extract. Under optimum CE‐ESI‐TOF‐MS conditions we achieved the determination of nine compounds from the polar fraction in 35 min. Furthermore, by using the HPLC‐ESI‐TOF‐MS method, a total of 23 compounds corresponding to phenolic acids and the flavonoid family were identified from almond skin in only 9 min. The sensitivity, together with mass accuracy and true isotopic pattern of TOF‐MS, allowed the identification of a broad series of known phenolic compounds present in almond‐skin extracts using HPLC and CE as separation techniques.
Behavioral arousal in response to stress and drug cue in alcohol and cocaine addicted individuals versus healthy controls
Authors: Chaplin Tara M. , Hong Kwangik , Fox Helen C. , Siedlarz Kristen M. , Bergquist Keri , Sinha Rajita
Published: June 2010

Negative emotional arousal in response to stress and drug cues is known to play a role in the development and continuation of substance use disorders. However, studies have not examined behavioral indicators of such arousal.

Objective

The current study examined behavioral and bodily arousal in response to stress and drug cue in individuals with alcohol dependence and cocaine dependence as compared to healthy controls using a new scale.

Methods

Fifty‐two alcohol dependent (AD group), 45 cocaine dependent (COC group), and 68 healthy controls (HC group) were exposed to individually developed stressful, drug‐cue, and neutral‐relaxing imagery. Behavioral and bodily responses were assessed with a new scale, the Behavioral Arousal Scale (BAS).

Results

The BAS showed acceptable inter‐rater reliability and internal consistency and correlated with subjective negative emotion and craving. BAS scores were higher in stress than neutral conditions for all three groups. COC participants showed higher BAS response to stress than AD or HC participants. COC and AD participants showed greater BAS response to drug cue than HC participants.

Conclusion

Behavioral arousal is a domain in which stress and drug related arousal is expressed and assessment of this domain could provide unique information about vulnerability to craving and relapse in addicted populations. Copyright © 2010 John Wiley & Sons, Ltd.
Metabolic networks for assessment of therapy and diagnosis in Parkinson's disease
Authors: Hirano Shigeki , Eckert Thomas , Flanagan Toni , Eidelberg David
Published: June 2010

Neuroimaging and modern computational techniques like spatial covariance analysis have contributed greatly to the understanding of neural system abnormalities in neurodegenerative disorders such as Parkinson's disease (PD). The application of network analysis to metabolic PET data obtained from patients with PD has led to the identification and validation of two distinct spatial covariance patterns associated with the motor and cognitive manifestations of the disease. Quantifying the activity of these patterns in individual subjects has provided an objective tool for the assessment of treatment efficacy and differential diagnosis. We have found that activity of the PD motor‐related network is modulated by antiparkinsonian treatments such as dopaminergic therapy, deep brain stimulation (DBS), and subthalamic nucleus (STN) gene therapy. By contrast, the cognitive‐related network is not altered by these interventions for PD motor symptoms. This pattern may however change in response to therapies targeting the cognitive symptoms of this disorder. Recent work has focused on the identification of specific network biomarkers for atypical parkinsonian conditions such as multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). These disease‐related patterns can potentially be used in an automated imaging‐based algorithm to classify patients with these disorders. © 2009 Movement Disorder Society
MRI and cognitive impairment in Parkinson's disease
Authors: Ibarretxe‐Bilbao Naroa , Tolosa Eduardo , Junque Carme , Marti Maria‐Jose
Published: June 2010

Patients with Parkinson's disease (PD) may present impairment in cognitive functions even at early stages of the disease. When compared with the general population, their risk of dementia is five to six times higher. Recent investigations using structural MRI have shown that dementia in PD is related to cortical structural changes and that specific cognitive dysfunctions can be attributed to atrophy in specific structures. We review the structural MRI studies carried out in PD using either a manual region of interest (ROI) approach or voxel‐based morphometry (VBM). ROI studies have shown that hippocampal volume is decreased in patients with PD with and without dementia; in addition, hippocampal atrophy correlated with deficits in verbal memory. VBM studies have demonstrated that dementia in PD involves structural changes in limbic areas and widespread cortical atrophy. Findings in nondemented patients with PD are less conclusive, possibly because cognitively heterogeneous groups of patients have been studied. Patients with PD with cognitive impairment and/or visual hallucinations present greater brain atrophy than patients without these characteristics. These findings suggest that cortical atrophy is related to cognitive dysfunction in PD and precedes the development of dementia. Structural MRI might therefore provide an early marker for dementia in PD. © 2009 Movement Disorder Society
Novel soluble fluorinated poly(ether imide)s with different pendant groups: Synthesis, thermal, dielectric, and optical properties
Authors: Liu Yu , Xing Yan , Zhang Yunhe , Guan Shaowei , Zhang Haibo , Wang Yu , Wang Yongpeng , Jiang Zhenhua
Published: June 2010

Three types of new bis(ether dianhydride) monomers, [4,4′‐(2‐(3′‐methylphenyl)‐1,4‐phenylenedioxy)‐diphthalic anhydride (4a)], [4,4′‐(2‐(3′‐trifluoromethylphenyl)‐1,4‐phenylenedioxy)‐diphthalic anhydride (4b)], and [4,4′‐(2‐(3′,5′‐ditrifluoromethylphenyl)‐1,4‐phenylenedioxy)‐diphthalic anhydride (4c)] were prepared via a multistep reaction sequence. Three series of soluble poly(ether imide)s (PEIs) were prepared from the obtained dianhydrides by a two‐step chemical imidization method. Experimental results indicated that all the PEIs had glass transition temperature in the range of 200–230 °C and the temperature of 5% weight loss in the range of 520–590 °C under nitrogen. The PEIs showed excellent solubility in a variety of organic solvents due to introduction of the bulky pendant groups and were capable of forming tough films. The casting films of PEIs (80–91 μm in thickness) had tensile strengths in the range from 88 to 117 MPa, tensile modulus from 2.14 to 2.47 GPa, and elongation at break from 15 to 27%. The casting films showed UV‐Vis absorption edges at 357–377 nm, low dielectric constants of 2.73–2.82, and water uptakes lower than 0.66 wt %. The spin‐coated films of PEIs presented a minimum birefringence value as low as 0.0122 at 650 nm and low optical absorption at the optical communication wavelengths of 1310 and 1550 nm. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3281–3289, 2010
Streaming birefringence as a rheological research tool
Authors: Wayland Harold
Published: June 2010

This paper reviews the theoretical and experimental evidence currently available to establish criteria to aid the experimenter who wishes to use streaming birefringence as a tool for studying fluid flow. Instrumental techniques are reviewed, and the possibilities for both qualitative and quantitative flow visualization by streaming birefringence in pure Newtonian liquids, colloidal suspensions and dilute and concentrated polymer solutions are discussed. Methods of reconstruction of the velocity and stress fields from birefringence data are outlined.
Rheo‐optical properties of polymers. X. Relaxation
Authors: Legrand D. G. , Haaf W. R.
Published: June 2010

Light scattering relaxation in thin strained polyethylene films has been determined. Results for swollen and unswollen films are presented. Concurrent studies of stress relaxation indicate that the mechanism by which relaxation takes place is associated with changes in the average fluctuation in refractive index of the material. The ratio of the change in the fluctuation in refractive index to stress appears to be independent of time.
Differential thermal analysis of linear polyesters
Authors: Schulken R. M. , Boy R. E. , Cox R. H.
Published: June 2010

Differential thermal analysis (DTA) was used to measure crystallization, melting, and glass transition temperatures of poly(ethylene terephthalate), poly‐1,4‐cyclohexylene‐dimethylene terephthalate, and some copolyesters. These values are affected in different ways by systematic changes in such factors us copolymerination, molecular block formation, crystal perfection, nucleation, thermal history, and orientation. At least two types of abnormally high melting structures were formed and identified. The stability of these polymers to thermal and oxidative degradation was studied by DTA.
Dynamic differential thermal analysis of the glass transition interval
Authors: Wuxderlich Bernhard , Bodily David M.
Published: June 2010

Dynamic differential thermal analysis (DDTA) will be described and its application to the study of the glass transition interval of polystyrene will be discussed. The mode of operation involves reproducible cooling from the molten state through the glass transition interval and subsequent heating, both at reproducible linear rates of temperature change. Data on the temperature of half‐freezing on cooling and on the temperature of the peak and (or) minimum in the heat capacity have been collected and will be compared with theoretical expressions derived on the basis of the hole theory of liquids. From the half‐freezing temperature on cooling; which is taken to be a mean fictive temperature, properties of a mean hole are calculated for polystyrene. (Mean molar hole volume = 21.9 cm.3, energy 1600 cal., activation energy 157,600 cal.; relaxation time at the fictive temperature 5.5 min,) DDTA will be shown to be applicable to the determination of the second freezing‐in process of polystyrene which occurs over a range of 230 to 350°K. and is thought to involve the librational motion of the phenyl rings.
Thermal analysis of high polymers: Differential thermal analysis and dynamic electrothermal analysis
Authors: Chiu Jen
Published: June 2010

The presentation consists of two parts. In the first part, a modification of a previously reported high‐resolution differential thermal analysis apparatus is described which extends the temperature range to 1100°C. and permits operation at pressures as low as 10μ. A sample of less than 1 mg. may be used to give well defined thermograms. The thermal behavior of an aromatic polyimide was studied and also of TFE‐fluorocarbon rosins in nitrogen and oxygen at various pressures. In the second part, an apparatus for performing simultaneous differential thermal analysis (DTA) and electrothermal analysis (ETA) is described. Changes in both heat content and electrical resistivity of a single sample are followed continuously as a function of sample temperature. Physical transitions such as melting, crystallization, glass transition, vaporization, and crystalline structural changes, and decomposition reactions are readily studied for a variety of polymer systems.
Colloidal macromolecular phenomena
Authors: Battista O. A.
Published: June 2010

Colloidal macromolecular phenomena represent a novel segment of polymer chemistry. They are associated with the unique physical behavior of discrete, particulate, and highly organized aggregates of hundreds or thousands of long chain molecules having dimensions roughly between those of the smallest viruses and the larger bacteria. Unique rheological and other functional properties are exhibited by unhinged colloidal macro‐molecular micro crystals possessing truly colloidal dimensions, namely, circular or rectangular rods, or platelets of the order of 25 A. × 50 A. × >1000 A., properties that are in large measure independent of chemical composition. Two commercial products now are available utilizing colloidal macromolecular phenomena (Avicel micro crystal line cellulose and Baymal colloidal alumina). It is believed that these are the forerunners of many new colloidal macromolecular products to come, new products fashioned from microcrystals of both synthetic and natural high polymers, from organic as well as inorganic high polymers, or combinations of both of them.
Diffusion of water through hydrocarbon liquids
Authors: Schatzberg Paul
Published: June 2010

Diffusion of water through slightly volatile hydrocarbon liquids can be described by dm/dt = –DA(dc/dx) where dm/dt is the rate of mass transport, A the area, dc/dx the concentration gradient, and D the diffusion coefficient. For dilute systems, D can be determined from an experimental evaluation of dm/dt, A, and dc/dx. In the experimental arrangement used, water diffuses through a layer of hydrocarbon lying fiat on a layer of water in a small beaker which is attached to a recording microbalance. The system is closed and maintained anhydrous with MgClO4. When steady‐state diffusion is attained, dm/dt is measured directly by the microbalance. Water diffuses from maximum concentration (water‐hydrocarbon interface) to zero concentration (hydrocarbon‐anhydrous air interface). Thus, the gradient dc/dx becomes –s/l where s is the solubility of water in the hydrocarbon, and l is the layer thickness. Therefore D = (dm/dt)l/(sA). Diffusion coefficients have been determined for water diffusing through n‐hexadecane and 2, 6, 10, 15, 19, 23‐hexamethyl tetracusane at five temperatures from 25–45°C. Results give a good fit in an Arrhenius plot. Diffusion activation energies are calculated as well as entropies of activation based on the Eyring absolute rate theory. Results are compared with data for the diffusion of water through polyethylene and polypropylene.
Solution and diffusion of gases and vapors in silicone rubber membranes
Authors: Barrer R. M. , Chio H. T.
Published: June 2010

Solution and diffusion of He, Ne, Ar, Kr, Xe, H2, N2, O2, and n‐C4H10 have been studied in filled dimethylpolysiloxane elastomers, at temperatures between 0 and −37°C. for all penetrants, and down to −78°C. for some. Crystallization of the rubber, commencing at about −50°C. resulted in large decreases in permeability and diffusion coefficients and smaller decreases in solubility. Diffusion coefficients were measured in three different ways and solubility coefficients in two. Above the crystallization temperature, the results by all methods agreed for a lightly filled rubber but for a rubber with a high filler content especially when partially crystalline (i.e., below −50°C.) differences were observed between solubility coefficients measured directly and those derived from permeation and diffusion. These differences arc related to the heterogeneity of the medium and to consequent differences in diffusion coefficients obtained by the time‐lag and steady‐state methods. Diffusion and solubility coefficients both show relationships with other physical properties. Permeabilities of the silicone rubbers to gases are high, and selectivity can be good as between appropriate pairs of molecules.
Structure of cholla gum (Opuntia fulgida)
Authors: Parikh V. M. , Jones J. K. N.
Published: June 2010

The structure of cholla gum has been investigated using (a) the methylation procedure, (b) by oxidation of the polysaccharide with periodate (the Smith procedure), and (c), by its partial hydrolysis with the formation of sugars and oligosaccharides. It is composed of a main chain of D‐galactopyranose residues fi‐linked 1 → 3 and/or 1 → 6, to which are attached side chains. These branches contain D‐galacturonic acid, D‐galactose, and D‐xylose, all in the pyranose form, and L‐rhamnose and L‐arabinofuranose residues. The chains are terminated by D‐xylopyranose or L‐arabinofuranose units. D‐Xylose is present only in terminal residues.
The sorption of glucomannan and xylan on α‐cellulose wood fibers
Authors: Clayton D. W. , Phelps G. R.
Published: June 2010

The rates of sorption of spruce glucomannan and of a modified birch xylan (containing less than 3% uronic anhydride) upon never‐dried α‐cellulose wood fibers in 0.02N alkali have been measured at 4 temperatures ranging from 5–40°C. By labeling the glucomannan with carbon‐14 and the xylan with tritium it was possible to measure the rates of sorption of each hemicellulose alone or in solution together at the same concentration. In both cases the rates of sorption of the glucomannan were about twice those for the xylan. Average activation energies (kcal./mole) derived from the rates were as follows: glucomannan alone, 3.8; glucomannan in admixture with xylan, 3.1; xylan alone or in admixture with glucomaunan, 6.3. The initial rates of sorption, estimated graphically by a methods which is shown to have severe theoretical limitations, gave higher values for the activation energies, viz.: glucomannan alone, 6.6; glucomannan in admixture with xylan, 5.8; xylan alone, 10.0; xylan in admixture with glucomannan, 10.1 kcal./mole. All these values suggest that the sorption of both hemicelluloses is physical. Although the initial rate of sorption of the xylan was not significantly affected by the presence of the glucomannan, its total sorption after 10 min was reduced by an average of 18% when glucomannan was present. The lower rate of sorption of the xylan is ascribed to the presence of its uronic acid carboxylic groups. A small percentage of these groups can apparently override the conformational similarity of xylan and cellulose.
Characterization of cellulose gels by small angle light scattering
Authors: Beebe E. V. , Coalson R. L. , Marchessault R. H.
Published: June 2010

An experimental evaluation of the light scattering from two water‐swollen cellulose gels and the corresponding solvent‐exchanged cellulose gels has been made. The two gels were prepared from a commercial viscose by methods which gave different degrees of swelling. The solvent exchanged gels were finally imbibed with silicone fluids whose refractive indices (n) covered the range 1.40–1.59. The Debye‐Bueche theory for scattering from a heterogeneous solid was applied to the data. The observed scattering could be interpreted in terms of refractive index or density fluctuations which were less for the sample with lover degree of swelling. The average periodicity of the density fluctuations increased as n of the imbibition fluid in the solvent‐exchanged samples approached the value, na, for the amorphous regions and maximized in this region. Comparative lateral order distribution information could be derived from the data. From the results it could be shown that the water‐swollen gel is more homogeneous then after solvent exchange but the difference was less for the less swollen system. The evidence collected supports the idea that cellulose gels are, to a first approximation, three‐phased systems involving high order and low order regions as well as micropores. Electron micrographs of thin sections of the solvent‐exchanged gels served to confirm this hypothesis.
Small angle x‐ray scattering from bulk crystalline polymers
Authors: Geil P. H.
Published: June 2010

It is tempting to correlate the discrete small angle x‐ray diffraction (SA) spacings obtained using polymers crystallized from the melt with the thickness of the lamellae present in the sample. There is a good correlation of SA spacing and the electron microscope (EM) observed thickness for polymers crystallized from solution. However, a review of available data in which SA and EM observations have been made on the same sample (for polyethylene, polyoxymethylene, polychlorotrifluoroethylene, and polyethylene oxide) show that the largest HA spacing is not in agreement with the EM observed thickness. In several of the polymers the second largest spacing, which is often not an order of the largest, is in reasonable agreement with the EM value. Possible causes of these discrepancies are discussed.
Introductory remarks for symposium on transitions and relaxations in polymers
Authors: Royer R. F.
Published: June 2010

Most organic polymers show a complex array of transition and/or multiple relaxation phenomena in addition to the classical glass transition and the melting point. An amorphous hydrocarbon backbone polymer such as an equimolar, random copolymer of ethylene and propylene, can exhibit, four types of relaxation regions: (1) motion of the entire chain as a unit; (2) motion of a chain segment of perhaps 50–100 carbon atoms, i.e., the glass transition; (3) motion of a 2, 3, or 4 carbon atom moiety about the chain axis, i.e., the γ transition: (4) motion of a side group, such as CH3 in a propylene unit. A moderately crystalline hydrocarbon backbone polymer, i.e., polypropylene, can show all of the loss peaks noted above but in addition may exhibit peaks as follows: (1) melting point; (2) a first‐order transition from one crystal type to another; (3) motion of side groups such as CH3 within the crystallites; (4) interactions between crystallites and amorphous regions; (5) frictional losses within crystallites. Single crystals of linear polyethylene show several loss peaks related to loss peaks in partially crystalline polyethylene. Additional types of loss mechanisms arise in polymers such as polyethylene glycol terephthalate, polycarbonates, cellulose derivatives, and nylon, in which different types of moieties alternate along the chain. Different teat methods varying in specificity toward molecular groups in frequency and in sensitivity are needed to elucidate the full spectrum of loss mechanisms. Brief comment is made on the dielectric data of Kheir showing two clearly resolved loss peaks for 5% cellulose acetate in dioxane.
Ellipsoid model for polyelectrolytes
Authors: Kurata Michio
Published: June 2010

The expansion factor of polyelectrolytes is calculated by using an equivalent ellipsoid model which is essentially the same as that used by Kurata, Stockmayer, and Roig in the theory of excluded volume effect of non‐ionic polymers. The Donnan‐Kimball approximate solution of the Poisson‐Boltzmann equation is used for evaluating the electric free energy of a chain. The result h applied to the calculation of the intrinsic viscosity [η] as a function of the molecular weight M and salt concentration ρs, As a consequence, [η] is predicted to be expressible in the form

over a wide range of the variables. Here K, Bn and Φ0 are constant independent of M and Ps. In a limited range of large ps values, for example 0.1 ∼ 1 mole 1.−1 for a 1:1 added salt, the parameter Be(Ps) is proportional to Ps−1; but in the range of lower value, of Ps, for example 0.005 ∼ 0.1 mole 1.−1, Be(ps) becomes proportional to a lower inverse power of ps. For still lower values of ps, the above equation is no longer valid, because Be(Ps) becomes a function of M rather than of ps, In this range, the polyelectro‐lyte chain is in an extended rodlike form.
Temperature dependence of polymer viscosity. The influence of shear rate and stress
Authors: Porter Roger S. , Johnson Julian F.
Published: June 2010

Apparent flow activation energies evaluated from viscosity changes with temperature can be calculated in the non‐Newtonian region at either constant shear rate, E, or at constant shear stress, E. For many linear, amorphous polymere, it can be shown that E is independent of stress over the full range for which shear stress data tire reported. This conclusion also holds for solutions of several polymer types. Anomalous results are documented only for branched polyethylene. E decreases with shear in the non‐Newtonian region approaching a lower limit corresponding to the “power law” region. The relative changes in E with shear rate can be expressed in terms of reduced variables. The absolute change in E with shear rate can he used as a measure of polymer molecular weight distribution.
Normal stresses, non‐Newtonian flow, and dynamic mechanical behavior of polymer solutions
Authors: Kotaka Tadao , Osaki Kunihiro
Published: June 2010

Complex dynamic shear moduli, shear and normal stresses in steady shearing flow, and complex moduli with superposed steady shear are investigated in both theoretical and experimental aspects. Firs) it summary of phenomenological and molecular theories is given. Experimental tests of phenomenological theory are made by comparing dynamic (linear viscoelastic) data and steady shearing flow (nonlinear viscoelastic) data. It is found that the recent theory of memory fluids is quite satisfactory and also the results show that the action of normal stress in steady shearing flow is mainly pull in the direction of the flow line. The behavior of dilute polymer solutions (near A condition are best approximated by the molecular theory of Zimm, particularly at very low shear rates. At higher shear rates, the Zimm theory fails in predicting the appearance of non‐Newtonian viscosities and nonquadratic normal stresses. Various proposed modifications of the theory are examined experimentally. The behavior of concentrated polymer solution does not seem to fit any of the existing molecular theories; therefore, some typical features of the experimentally observed behavior of concentrated solutions are simply summarized. The results of the measurements of complex moduli with superposed steady shear show that in the low‐frequency region the effect of superposed shear rate results in a much larger decrease in the real part of the complex modulus that in the imaginary part, while in the higher‐frequency region the real part is again decreased but the imaginary part is increased with the increase of superposed shear rate.
On the Structure and Properties of Polyamides. XXVIII. Crystallization of Polycaprolactam Without a Thermal History
Authors: Tomka J. , Šebenda J. , Wichterle O.
Published: June 2010

The time lags for crystallization of polycaprolactam without a thermal history have been measured by nephelometry. The effects of crystallization temperature, degree of polymerization, diluent, and crosslinking have been investigated. Polymer without a thermal history was prepared by activated alkaline polymerization at the desired crystallization temperature, so that the polymer had never previously been crystalline. The dependence of the time lag τ on temperature T and the degree of polymerization P obeys the theoretical relation τ = const. (Tm — T)‐−bPc If we substituted for Tm the melting temperatures corrected for the content of noncrystallizable material we obtained b = 5.85. This value is close to the theoretical value 6, derived under the assumption that the diffusion of segments into the nucleus is proportional to the number of chains forming the surface of the cylindrical nucleus. Measurement of time lags for polycaprolactam crosslinked by means of methylenebiscaprolactam has corroborated the assumption that the viscosity near the surface of the crystal is not identical with the macroscopic viscosity of the melt, in agreement with the fact that the determined value of c = 1.58 is lower than 3.4. The effect of the diluent, N‐methyl‐caprolactam on the depression of Tm outweighs that of the viscosity decrease. The dilatometric measurements of the kinetics of crystallization of polycaprolactam without a thermal history have confirmed that both the time lag and the secondary crystallization can appreciably affect the value of the exponent n in Avrami's equation. If we evaluate the kinetics of the primary crystallization in terms of Avrami's equation using experimental values of time lags, the value of the exponent n is close to 4, which corresponds to a sporadic nucleation and three‐dimensional growth. If, however, the secondary crystallization is not separated and the start of the crystallization is considered to be the moment when the volume change is perceivable experimentally, then we obtain n ≈ 2. This indicates that conclusions on the mechanism of crystallization drawn from the value of the exponent n may be questionable.
Endgroups in Poly (methyl Methacrylate) Initiated by Photosensitized Ferric Salts in Aqueous Media
Authors: Saha Mihir Kumar , Mukherjee Asish R. , Ghosh P. , Palit Santi R.
Published: June 2010

Photosensitized ferric salts (ferric chloride, as well as bromide and perchlorate) have been used as initiators of aqueous polymerization of methyl methacrylate under varied conditions. Analysis of endgroups in the resulting polymers have been made by the application of dye techniques. Both hydroxyl and halogen endgroups have been traced in the polymers in varying proportions except in case of perchlorate where only hydroxyl endgroups have been detected. Some of the results are in sharp contrast with those reported by Evans et al. While increasing concentration of both ferric chloride and bromide was associated with a sharp fall in the total endgroup content of the polymers, ferric perchlorate did not show such effect. Specific action of some anions derived from additives such as salts and acids on the total endgroup content of the polymer was also investigated. Total endgroup content of the polymer decreased appreciably when a halide or a halogen acid was used in the polymerization medium, the effect of bromide being more predominant than the chloride. No such effect was observed in the case of potassium perchlorate, perchloric acid, and potassium sulfate as the additive. An explanation has been suggested for such specific action of anions.
Analysis of NMR and Vibrational Spectra and Conformational Structure of Stereoisomers of 2,4,6‐Trichloroheptane
Authors: Doskočilová D. , Štokr J. , Schneider B. , Pivcová H. , Kolinsky M. , Petránek J. , Lím D.
Published: June 2010

The infrared and NMR spectra of syndiotactic, isotactic, and heterotactic 2,4,6‐trichloroheptane, model compounds of poly(vinyl chloride), have been measured over a wide temperature range. Conformational structures of these stereoisomers have been determined from C—Cl stretching vibrations in infrared spectra and from the temperature dependence of vicinal coupling constants obtained by a four‐spin analysis of the methylene proton bands in NMR spectra.