bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorescence hysteroscopy using 5‐aminolevulinic: A descriptive study
Authors: Wyss Pius , Degen Andrea , Caduff Rosmarie , Hornung Rene , Haller Urs , Fehr Mathias
Published: August 2003

Background and Objectives

To assess the feasibility of fluorescence hysteroscopy following topical ALA application and to descript the optical appearance of normal and neoplastic endometrium.

Study Design/Materials and Methods

Fifty‐four patients scheduled for routine hysteroscopy and D&C were assigned to the study group using topically applied ALA. Two milliliters of a 2% 5‐ALA‐solution at pH = 4.0 (ASAT AG/Zug, Switzerland) was administrated into the uterine cavity 4 hours before fluorescence hysteroscopy, using a STORZ‐D‐Light (Tuttlingen, Germany) system. Hysteroscopic findings were compared to the histological diagnosis of hematoxylin & eosin (H&E) stained sections. In the study group, 60 histological specimens were taken (47 materials of curettage and 13 targeted biopsies). The percentage of fluorescence positive patients was calculated.

Results

The rate of fluorescent endometrial samples was low in atrophic endometrium 1/16 (6.2%). Endometrial carcinoma were diagnosed in two patients. Both cases exhibited selective and intense PpIX‐mediated red fluorescence. Fluorescence hysteroscopy could not differentiate between hyperplastic areas with or without atypia. Minimal uterine cramps or discomfort following ALA instillation were complained by 30 (56%) patients, no pain was indicated by 24 patients (44%).

Conclusions

Fluorescence hysteroscopy following intrauterine application of ALA is feasible. Cancerous, hyperplastic, and secretory endometrial tissue showed high red fluorescence. Lasers Surg. Med. 33:209–212, 2003. © 2003 Wiley‐Liss, Inc.
Comparative in vitro percutaneous penetration of 5‐aminolevulinic acid and two of its esters through excised hairless mouse skin
Authors: van den Akker Johanna T.H.M. , Holroyd J. Andrew , Vernon David I. , Sterenborg Henricus J.C.M. , Brown Stanley B.
Published: August 2003

Background and Objectives

ALA esters have been developed to improve PpIX production in ALA–PDT, but they do not perform as well in skin as they do in cells and the bladder.

Study Design/Materials and Methods

The in vitro penetration across normal mouse skin of ALA and its methyl and hexyl ester was determined for different application concentrations. ALA and the esters were also applied to tape stripped skin to determine the effect of the stratum corneum.

Results

The penetration of ALA and the esters was higher through tape stripped skin than through normal skin (P < 0.01), showing that the stratum corneum is an important barrier. The experiments with different application concentrations indicated that the skin penetration through normal skin and tape stripped skin is highest for ALA and lowest for the hexyl ester.

Conclusions

The differences in skin penetration properties could be (co‐)responsible for the finding that ALA esters do not induce substantially higher PpIX levels in in vivo skin. Lasers Surg. Med. 33:173–181, 2003. © 2003 Wiley‐Liss, Inc.
Light emitting diode irradiation protect against the amyloid beta 25–35 induced apoptosis of PC12 cell in vitro
Authors: Duan Rui , Zhu Ling , Liu Timon Cheng‐Yi , Li Yan , Liu Jiang , Jiao Jianling , Xu Xiaoyang , Yao Libo , Liu Songhao
Published: August 2003

Background and Objectives

Whether light emitting diode (LED) irradiation has effects on “β‐amyloid (Aβ) induced apoptosis,” a leading hypothesis of the cause of Alzheimer's disease (AD), or not?

Study Design/Materials and Methods

Monolayer cell cultures of PC12 were subjected to Aβ or/and LED irradiation at various intensity. Cell apoptosis was confirmed by morphological criteria, DNA fragmentation assay, and FAScan flow cytometer assay.

Results

Treatment of the cells with LED irradiation significantly diminished Aβ induced apoptosis within 24 hours.

Conclusions

The LED irradiation, when utilized at power of 0.9 W/m2 and 60 minutes has significantly diminished Aβ induced apoptosis of PC12 cells. Lasers Surg. Med. 33:199–203, 2003. © 2003 Wiley‐Liss, Inc.
Proteomic snapshot analyses of preribosomal ribonucleoprotein complexes formed at various stages of ribosome biogenesis in yeast and mammalian cells
Authors: Takahashi Nobuhiro , Yanagida Mitsuaki , Fujiyama Sally , Hayano Toshiya , Isobe Toshiaki
Published: August 2003

I.
Introduction
288

II.
Transcription and Processing of the Pre‐rRNA in the Ribosome Biogenesis of Yeast Cells: A Model for Eukaryotic Cells
290

III.
Trans‐Acting Factors Involved in the Pre‐rRNA Processing and Assembly in Yeast Cells
291

A.  Trans‐Acting Proteins That Act with snoRNAs
291

B.  Trans‐Acting Factors Involved in the rRNA Cleavages
293

C.  Trans‐Acting Factors Involved in the rRNA Editing and Conformational Rearrangement
296

IV.
Isolation and Proteomic Characterization of Pre‐rRNP Complexes Formed During Ribosome Biogenesis in Yeast Cells
296

A.  Experimental Approaches to Characterize Pre‐rRNP Complexes
296

B.  90S Pre‐rRNP Complexes Formed at Very Early Stages of Ribosome Biogenesis
299

C.  Pre‐rRNP Complexes Formed at Early/Middle Stages of Ribosome Biogenesis
302

D.  Pre‐rRNP Complexes Formed at Later Stages of Ribosome Biogenesis
303

 V.
Isolation and Proteomic Characterization of Pre‐rRNP Complexes Involved in Mammalian Ribosome Biogenesis
304

A.  Ribosome Biogenesis in Mammalian Cells
304

B.  Proteomic Analysis of the Pre‐rRNP Complexes Associated with Nucleolin: A Major Nucleolar Protein
305

C.  Reverse‐Tagging Methodology Applied to Human Trans‐Acting Proteins Involved in Ribosome Biogenesis
310

D.  Isolation and Proteomic Analysis of Human Parvulin‐Associating Pre‐rRNP Complexes
310

 VI.
Proteomic Analysis of the Nucleolus of Mammalian Cells
312

VII.
Conclusions
312

VIII.
Abbreviations
314

References
314

Proteomic technologies powered by advancements in mass spectrometry and bioinformatics and coupled with accumulated genome sequence data allow a comprehensive study of cell function through large‐scale and systematic protein identifications of protein constituents of the cell and tissues, as well as of multi‐protein complexes that carry out many cellular function in a higher‐order network in the cell. One of the most extensively analyzed cellular functions by proteomics is the production of ribosome, the protein‐synthesis machinery, in the nucle(ol)us—the main site of ribosome biogenesis. The use of tagged proteins as affinity bait, coupled with mass spectrometric identification, enabled us to isolate synthetic intermediates of ribosomes that might represent snapshots of nascent ribosomes at particular stages of ribosome biogenesis and to identify their constituents—some of which showed dynamic changes for association with the intermediates at various stages of ribosome biogenesis. In this review, in conjunction with the results from yeast cells, our proteomic approach to analyze ribosome biogenesis in mammalian cells is described. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:287–317, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mas.10057
Atmospheric pressure photoionization mass spectrometry
Authors: Raffaelli Andrea , Saba Alessandro
Published: August 2003

I.
Introduction and Historical Background
318

II.
Short Theoretical Outline
319

A.  The Use of a Dopant
319

    1.  APPI–MS with a Dopant
320

B.  Further Parallel Reactions in APPI–MS
321

III.
APPI Sources—Overview
321

A.  In‐Line Geometry Source
321

B.  Orthogonal Geometry Source
323

IV.
Factors that Influence the Performance of APPI
323

A.  The Dopant
323

B.  Mobile Phase Composition
323

 V.
Applications
324

A.  Pharmaceutical and Drug Metabolism
324

    1.  Non‐Steroidal Compounds
325

    2.  Steroidal Compounds
327

B.  Environmental
327

C.  Natural Products
328

D.  Synthetic Organics
329

VI.
Conclusions
330

Acknowledgments
330

References
330

Atmospheric pressure photoionization (APPI) is the last arrival in the family of atmospheric pressure ionization (API) methods to couple mass spectrometry (MS) to liquid‐phase separation techniques. The basic idea was to further extend the fields of application of liquid chromatography (LC)–MS to those molecules that are not, or are poorly amenable, to electrospray (ESI) or APCI. The present review explores the literature. After a short introduction with an historical background and the premises for its development, we describe the technique, its physical principles, and the factors that affect its efficiency. The review also presents a survey of applications in different fields. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:318–331, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mas.10060
Bacterial production of PHA from lactose and cheese whey permeate
Authors: Povolo Silvana , Casella Sergio
Published: August 2003

Due to the large availability of agro‐industry wastes containing potentially exploitable substrates, such as whey from dairy industry, a study on the bacterial conversion of lactose and whey permeate to poly(β‐hydroxyalkanoate) (PHA) was undertaken. A first approach was carried out on culture collection strains. Among a number of strains tested, Hydrogenophaga pseudoflava DSM 1034 and Sinorhizobium meliloti 41 were found to grow on lactose and produce PHA. These findings suggested to investigate among a wider range of microorganisms by directly isolating new strains from soil. A number of soil bacteria were first isolated on a minimal medium containing lactose as unique carbon source and PHA‐accumulating traits were then investigated. Three isolates, identified by 16S rDNA sequence analysis as Sinorhizobium sp., Bacillus megaterium and Bacillus sp., were selected for their efficient growth and PHA production using lactose as carbon source. The same strains were also tested for their ability to accumulate PHA by direct fermentation of whey and whey permeate. Our results suggest that production of the polymer from cheese whey or whey permeate may be possible, although further research is needed to determine whether these microorganisms have the potential for commercial production of such biodegradable polymers.
Study of the influence of plasticizers on the thermal and mechanical properties of poly(3‐hydroxybutyrate) compounds
Authors: Baltieri Rodrigo Cirillo , Innocentini Mei Lucia H. , Bartoli Julio
Published: August 2003

The influence of four types of plasticizers, dioctyl phthalate (DOP), dioctyl adipate (DOA), triacetyl glycerol (TAG) and polyadipate (PA), in the thermal and mechanical properties of Poly(3‐hydroxybutyrate) (PHB), a highly crystalline biodegradable polyester, was evaluated in this work. The plasticizers were introduced alone or mixtures of them, using concentrations that varied from 5 to 30% wt. Their influence in some important polymer parameters as Tg, Tm and degree of crystallinity, and on its mechanical behavior, elongation and tensile strain were investigated. The best results were obtained for the sample with 30% TAG and that one using a binary mixture of plasticizers PA 20% and TAG 10%.
Factorial design in optimization of PHAs processing
Authors: Chiellini Emo , Grillo Fernandes Elizabeth , Pietrini Matteo , Solaro Roberta
Published: August 2003

Poly(hydroxyalkanoate)s (PHA)s, as all melt‐processed polymers, may undergo thermal degradation at temperatures close to the melting point. The primary purpose of the present study is to screen out process variables on the basis of a factorial design for two variables at two levels. The investigated parameters for PHA polymer samples processed in a torque rheometer were structure of PHA, processing temperature, and rotor speed. For polymers processed by compression molding, only the first two variables were considered and purification. The main effects and possible interactions were verified by the changes of molecular weight and thermal properties, as detected by DSC and TGA. It was observed that molecular weight decreased up to about 50% while the thermal properties did not appreciably change.
Biodegradable polymeric films based on microbial poly(3‐hydroxybutyrate). Effect of gamma‐radiation on mechanical properties and biodegradability
Authors: Miyazaki S.S. , Yep A.R. , Kolton F. , Hermida É.B. , Povolo F. , Fernandes E.G. , Chiellini E.
Published: August 2003

Two samples of microbial poly(3‐hydroxybutyrate) (PHB) having different molecular weight were used for the preparation of films to be exposed to gamma radiation. The effect of radiation on those samples with high molecular weight increased the fragility of the film. Biodegradability increased with time and reached about 95% after 18 days. Weight‐loss of both samples (irradiated and non‐irradiated) after 23 days were 100%, for those films with molecular weight of 265 kD.
Thermal and mechanical properties of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) plasticized by biodegradable soybean oils
Authors: Choi Jea Shin , Park Won Ho
Published: August 2003

The effects of soybean oil (SO) and epoxidized soybean oil(ESO) as biodegradable plasticizers for poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) were studied using thermal and mechanical analyses. PHBV/SO and PHBV/ESO blends were prepared by evaporating solvent from blend solutions. The levels of additive in the blend varied from 5% to 30%. As a plasticizer for PHBV, ESO was more effective than SO in depression of the glass transition temperature as well as in increasing the elongation at break and the impact strength of the films with increasing levels of additive. Biodegradation of the plasticized PHBV films was carried out by accelerated compost method. The degradation rates of the blend films with SO or ESO were found to be faster than that of PHBV film. From the thermogravimetric analysis, it was found that the thermal reaction between the epoxide groups of ESO and PHBV fragments with carboxylic chain ends, occurred during the degradation of PHBV/ESO blends.
Characterization of surface modified flax fibers and their biocomposites with PHB
Authors: Lee Seung Goo , Choi Sung‐Seen , Park Won Ho , Cho Donghwan
Published: August 2003

Flax fiber was treated with acetic anhydride or with ethylene plasma to improve adhesion with poly(3‐hydroxybutyrate) (PHB). The flax fiber surface became hydrophobic by the surface treatments. The ethylene plasma treated flax fiber has better thermal resistance and shows higher interfacial adhesion strength in flax/PHB biocomposite than the chemically modified flax fiber with acetic anhydride. Optimum conditions of the ethylene plasma treatment were found to be 0.5 cm3/sec of the ethylene flow rate and 50 W of the plasma power with 5 min of the treatment time.
Injection molded hybrid composites based on corn fibers and poly(vinyl alcohol)
Authors: Cinelli Patrizia , Lawton John W. , Gordon Sherald H. , Imam Syed H. , Chiellini Emo
Published: August 2003

Ongoing research cooperation between USDA and the University of Pisa, Italy has yielded several composite blends of poly(vinyl alcohol) (PVA) and corn fibers (CF). The USA is the largest producer of ethanol from cereal grains. Composites based on natural fibers alone are extremely sensitive to water. Their mechanical properties deteriorated upon the absorption of water, thus suggesting a limited usefulness of such formulations in practical applications. In this study, corn‐fibers produced during the wet milling process of corn for fuel ethanol were used to prepare composites. CF and PVA were processed in variable amounts in the presence of both dry/fluid plasticizers, such as glycerol and pentaerythritol. Composites prepared from CF in combination with PVA showed little change in their mechanical properties even after conditioning at variable relative humidities, as well as complete soaking in water. Composites tested after storage for one year under 50% relative humidity and 23°C exhibited mechanical properties similar to those of freshly prepared composites. Cornstarch was introduced in the formulation for the purpose of reducing the cost of the final product and to further increase the composition of natural components in the composites. Addition of starch moderately reduced the mechanical properties of the composites.
Biodegradable hybrid polymer films based on poly(vinyl alcohol) and collagen hydrolyzate
Authors: Chiellini Emo , Cinelli Patrizia , Ilieva Vassilka I. , Ceccanti Antonio , Alexy Pavol , Bakos Dusan
Published: August 2003

Hybrid blends of poly(vinyl alcohol) (PVA) and collagen hydrolyzate (CH), an added value waste from leather indutry, have been converted by blown molding extrusion, to environmentally degradable films.

Blown extruded films comprising 5‐15% of CH, were tested as sel fertilizing mulching films and analyzed for their propensity to enviromental degradation.

PVA/CH films rapidly disintegrate when buried in soil, and resulted promising for application such as transplanting films, with additional fertilizing action of CH.
Liquid mulch based on poly(vinyl alcohol). PVA‐soil interaction
Authors: Chiellini Emo , Cinelli Patrizia , D'Antone Salvatore , Ilieva Vassilka I. , Magni Simone , Miele Sergio , Pampana Silvia
Published: August 2003

This study is meant to provide a contribution in recent developments of biodegradable polymeric materials applied in agricultural practices with particular reference to the mulching segment. Special attention has been devoted to material based on renewable resources or utilization of waste products from agro‐industrial activities, thus suggesting cost‐effective and environmentally sound solutions to specific social needs. In the present contribution PVA solubility at room temperature has been improved by premixing with chemical additives and proteic materials. Waste materials from ethanol production by corn fermentation and from wood industries have been used as, respectively starch‐based and lignocellulosic additives. The prepared formulations were applied on the soil by conventional spraying agricultural equipment. Time of permanence of the film formed on the soil was monitored as well as the effect on corn growth and yield production. Finally, in order to investigate the final fate of the PVA applied on the soil, a test was performed in lysimeters, with half of the lysimeters cropped with maize plants. PVA amount applied for the mulching test was in order of 5‐10 g PVA/1 m2; under those conditions it resulted completely absorbed and no presence of PVA was recorded in the leached solutions.
Synthesis and thermal properties of epoxy resins from ester‐carboxylic acid derivative of alcoholysis lignin
Authors: Hirose Shigeo , Hatakeyama Tatsuko , Hatakeyama Hyoe
Published: August 2003

Alcoholysis lignin (AL) was dissolved in ethylene glycol and the obtained mixture was reacted with succinic anhydride to form a mixture of ester‐carboxylic acid derivatives (AL‐polyacid, ALPA). Ethylene glycol‐polyacid (EGPA) was also prepared from ethylene glycol. The obtained mixture of ester carboxylic acid derivatives was treated with ethylene glycol diglycidyl ether in the presence of catalytic amount of dimethylbenzylamine to form ester‐epoxy resins. The curing reaction was analyzed by Ozawa's method using differential scanning calorimetry. The activation energy of curing reaction in the initial step was found to be ca. 84 kJ mol−1. The molar ratios of epoxy groups to carboxylic acid groups ([EPOXY]/[AA] ratios) were varied from 0.8 to 1.3. The contents of ALPA in the mixture of ALPA and EGPA were also varied from 0 to 100%. Thermal properties of epoxy resins were studied by DSC and thermogravimetry. Glass transition temperatures of epoxy resins showed a maximum value of −11.5 °C when [EPOXY]/[AA] ratio was 1.1. Tg increased with increasing ALPA contents suggesting that lignin acts as a hard segment in epoxy resin networks. Thermal degradation temperatures of epoxy resins slightly decreased with increasing ALPA contents.
Mechanical and thermal properties of rigid polyurethane foams derived from sodium lignosulfonate mixed with diethylene‐, triethylene‐ and polyethylene glycols
Authors: Hatakeyama T. , Asano Y. , Hatakeyama H.
Published: August 2003

Sodium salt of lignosulfonic acid (LS), which was obtained as by‐product of cooking process in sulfite pulping, was solved in diethylene, triethylene or polyethylene glycol. Three series of polyurethane foams (LSPU) were synthesized by varying the LS content from 0 to 33 wt%. Apparent density (ρ) of LSPU foams ranged from 0.08 to 0.18 g cm−3 and was affected by both LS content and oxyethylene chain length. Glass transition temperatures increased with increasing amount of LS and with decreasing oxyethylene chain length. Thermal gravimetry analysis indicated that the LS component decomposes first and that the thermal stability increases with decreasing oxyethylene chain length. Compression strength and compression modulus increased linearly with increasing apparent density. It is concluded that LS is successfully utilized as a hard segment of rigid PU foams, whose thermal and mechanical properties can be tuned by changing the amount of LS and the length of soft oxyethylene chains.
New thermo‐molded biodegradable films based on sunflower protein isolate: aging and physical properties
Authors: Orliac Olivier , Silvestre Françoise
Published: August 2003

Smooth black films are obtained. Films plasticized with glycerol have the least stress at break, but show the highest strain at break (glycerol 33%: 6.7 MPa, 150%). The ethylene glycol family shows an increase in stress at break when the aliphatic chain length increases, while strain at break decreases. Lastly, a rigidification phenomenon of films occurs with the two plasticizers 1,2‐propanediol and ethylene glycol, which can be attributed to a loss of plasticizer (followed by HPLC). The triethylene glycol produces the most resistant films, with a great elasticity (TEG 33%: 9.5 Mpa, 100%). Moreover, the films produced with this plasticizer keep their properties during time, as good as films produced with glycerol. The water vapor permeabilities of all those films are low (in the region of 10−12 g.m−1.s−1.Pa−1); even if contact angle measurements carried out with water show the hydrophilic character of the films surface. This last result is in agreement with the water uptake tests which show a loss of plasticizer and an absorption of water (in the region of 100% of the dry matter of film); without considering the plasticizer nature, and this in spite of a nearly total insolubility of the crosslinked proteic network.
Effect of filler shape on mechanical properties of rigid polyurethane composites containing plant particles
Authors: Funabashi Masahiro , Hirose Shigeo , Hatakeyama Tatsuko , Hatakeyama Hyoe
Published: August 2003

The effect of types of fillers on mechanical properties of rigid polyurethane composite samples was investigated. Polyurethane (PU) composites were prepared using a molasses polyol (MP, a mixture of molasses and polyethylene glycol, Mw=200) diphenylmethane diisocyanate (MDI) and fillers. The following plant particles, bamboo powder, roast bamboo powder, wood meal, coffee grounds, ground coffee bean parchment and cellulose powder, were used as fillers. The mixture of MP and fillers was reacted with MDI by adding an adequate amount of acetone as a solvent. The content of fillers was defined as the ratio of filler weight to total weight of polyol and fillers. The filler content was varied from 10 to 90 wt%. Polyurethane (PU) composites were prepared using fillers with MP. Lengths of major axis and minor axis for each particle regarded as an ellipse were measured using an optical microscope. Averages of diameter and aspect ratio were derived for each plant particle. The relationships between these average values and the mechanical properties, such as strength and elastic modulus, determined by the compression tests were investigated. The effect of filler content was estimated using the apparent volume ratio which is determined as the ratio of the apparent volume of fillers to the reciprocal values of the apparent density of samples. The master curves of the relationships between the specific values of mechanical properties and the apparent volume ratio were obtained. It was found that the compression strength and the elastic modulus for composite samples with different fillers showed maximum values at average aspect ratio around 3. It was also found that the apparent volume ratio, where the mechanical properties showed maximums, decreases with increasing aspect ratio. Using master curves, it is possible to evaluate the mechanical properties of plant particle filled polyurethane composites are described.
Polycaprolactone based biodegradable polyurethanes
Authors: Wang Shu Hui , Silva Luiziana F. , Kloss Juliana , Munaro Marilda , Pinto de Souza Gabriel , Wada M. Alice , Gomez J. Gregório C. , Zawadzki S. , Akcelrud L.
Published: August 2003

Two series of segmented polyurethanes were prepared with systematic variation in soft and hard segment length. The soft segment was constituted by polycaprolactone (PCL) blocks of molecular masses 530 or 2000 and the hard segment (HS) by urethane blocks, in a concentration that varied from 12% to 44% in weight of the whole polyurethane. Morphological analyses indicated that the amount of crystallinity of copolymers was strongly dependent on the PCL molar mass and hard segment content. The copolymers with longer PCL soft segments (Mn=2000) were semicrystalline, but those with shorter PCL segment (Mn=530) were unable to crystallize. The primary factor affectingthe biodegradability of copolymers as evaluated by Sturm tests was the extent of the phase separation, and that the segmental blending of the less biodegradable polyurethane (HS) blocks with PCL in the amorphous phase had a critical unfavorable consequence, which may be attributed to the size of the accessible area by microorganisms.
Properties and adsorptive capacity of amino acids modified chitosans for copper ion removal
Authors: Dehonor‐Gómez Mariamne , Hernández‐Esparza Margarita , Ruiz‐Treviño F. Alberto , Contreras‐Reyes Roberto
Published: August 2003

This work presents the results of the modification of lateral groups of chitosan (2‐amino‐2‐desoxy‐β‐D‐glucose) by the reaction with different amino acids (glycine, L‐lysine, ‐glutamic acid and L‐isoleucine) under acid catalysis. The Cu2+ adsorption capacity of pure chitosan and of the chemically modified chitosans were also evaluated. The modification reaction favored the amide formation of the C‐2 carbon of the glycoside ring under the adopted reaction conditions: reaction time and temperature and using sulfuric acid as a catalyst. The Cu2+ adsorption kinetics and equilibrium response using pure chitosan and the chemically modified chitosans as adsorbents showes that the adsorption capacity of equilibrium depended on the initial ion concentration. The response of each adsorbent gave good correlation with Langmuir's isotherm model. The following maximum adsorption capacity constants were obtained: 172.4 mg/g for chitosan and 69.9, 34.4, and 26.7 mg/g for modified chitosan with glycine, L‐glutamic acid, and L‐lysine, respectively. The adsorptive capacity seems to be dependent on the length and complexity of the added group.
Malolactonate polymers and copolymers for biomedical applications
Authors: Bizzarri Ranieri , Chiellini Federica , Ober Christopher K. , Saltzman W. Mark , Solaro Roberta , Chiellini Emo
Published: August 2003

A new class of malolactonate polymers and copolymers with a wide range of lateral chain structures were synthesized by anionic ring opening polymerization of alkyl malolactonate monomers. The monomers were prepared in good yields according to established procedures. Final macromolecular and thermal characteristics were in agreement with the designed monomer structures. Molecular weights in the range 4‐20 kD were attained, as a result of chain transfer reactions. Representative polymeric compounds displayed stability up to 200 °C. Many of the obtained poly(alkyl malolactonate)s were able to sustain and promote with 3T3 murine fibroblasts adhesion and proliferation onto their surface.
Biodegradable starburst carbon chain polymer‐protein and lysine dendrite conjugates: adjustment of immune properties, DNA bonding and delivery
Authors: Vlasov Guennady P.
Published: August 2003

In the past decade, the development of gene therapy technology has focused on the design of new nonviral carriers for gene delivery. Proteins modified with polyethyleneimine[1] or polylysine[2] as well as dendrites[3] have shown to be perspective carriers for DNA targeted delivery. The usage of protein conjugates as carriers of biologically active compounds will depend on the adjustment of their immune properties. To investigate this we have prepared starburst carbon chain polymer/protein conjugates containing low molecular weight biologically active compounds, salsolinol and bradykinin, in the polymer moieties and studied their immune properties. We have shown that chemical structure of the polymer moiety determines the conjugate biodegradation as well as their immune properties. The starburst poly(N‐vinylimidazole) transferring poly(N‐vinylimidazole) and polylysine 3G lysine dendrite conjugates have been prepared. The study of their ability to bind DNA and to guarantee its targeted delivery have shown that they are perspective DNA carriers.
Surface patterning and biological evaluation of semi‐interpenetrated poly(HEMA)/poly(alkyl β‐malolactonate)s
Authors: Chiellini Federica , Bizzarri Ranieri , Ober Christopher K. , Schmaljiohann Dirk , Yu Tianyue , Saltzman W. Mark , Solaro Roberto , Chiellini Emo
Published: August 2003

Semi‐interpenetrating hydrogel networks were prepared by radical polimerization of monomer HEMA, co‐monomer EGDMA as cross‐linking agent and in the presence of 1 wt % of poly(alkyl β‐malolactonate)s. Biological evaluation in terms of cell adhesion and proliferation of the prepared materials showed the ability of HEMA‐based hydrogels to sustain a good cell adhesion and proliferation. Moreover, a method based on soft‐lithography to obtained surface microstructured semi‐interpenetrating hydrogel networks was developed, thus allowing for further investigation of the influence of surface topography on cell behavior.
A simple method suitable to test the ultimate biodegradability of environmentally degradable polymers
Authors: Chiellini Emo , Corti Andrea
Published: August 2003

A straightforward experimental set‐up derived from the Biometer Flask previously utilized for experiments of pesticides biodegradation, has been adopted for testing the ultimate biodegradability of natural, synthetic and semi‐synthetic polymeric materials on solid substrates such as soil and mature compost. The use of these whole substrates as incubation media in respirometric experiments, may negatively affect the accuracy of the test due to the large amount of carbon dioxide developed from the blanks, especially in the presence of specimen degrading at low or moderate rates. In the present test procedure soil and compost samples are diluted with perlite, a naturally occurring inert aluminum silicate widely utilized in horticultural applications, in order to ensure optimal conditions for the microbial growth while reducing the carbon dioxide emissions from the blanks. The results so far reported clearly indicate that the adopted procedure is extremely valuable and versatile for the appreciation of even subtle differences in the biodegradation rate of different polymeric materials, as well as for long‐term degradation experiments.
Strategies for detecting ecotoxicological effects of biodegradable polymers in agricultural applications
Authors: Fritz J. , Sandhofer M. , Stacher C. , Braun R.
Published: August 2003

Biodegradable is the long awaited and highly accepted property for materials (polymers) used in agricultural applications. Methods for determining biodegradability and material disintegration are established and already in use for routine analysis. Methods for analysing ecotoxic effects caused by biodegradable materials are neither established nor in routine use. In the past, biotests have been developed and optimised solely for investigations of single chemicals. Such tests are applicable even if they are not validated for the detection of undesired ecotoxicological effects deriving from biodegradation of polymers in soil. Since the biodegradation process does have an influence on the physical, chemical and biological status of the soil matrix, both biotests and chemical analysis are required in many cases. Theory, background data from method development and some results are presented.
Degradation of the blends of natural and synthetic copolyesters in different natural environments
Authors: Rutkowska Maria , Krasowska Katarzyna , Heimowska Aleksandra , Kowalczuk Marek
Published: August 2003

The paper presents results of the biodegradation of the blends of natural and synthetic copolyesters in two different natural environments. Environmental degradation took place in compost with activated sludge at sewage farm and ‐ for comparison ‐ in the Baltic Sea in Gdynia Harbour. Degradation of these blends was monitored for 16 weeks in compost and for 6 weeks in sea water. The changes in macroscopic features of surface and the weight loss of the samples were measured during the performed experiment. The characteristic parameters of compost and sea water were also controlled during all incubation time and their influence on the rate of biodegradation is discussed. The results of this study revealed that the natural aliphatic copolyester i.e. 3‐hydroxybutyrate‐co‐3‐hydroxyvalerate (PHBV) and its blends with the synthetic aliphatic‐aromatic copolyester of 1,4‐butandiol with adipic and terephthalic acids degrade faster in compost than in sea water. The rate of the biodegradation process depends on the composition of blends and different abiotic parameters of compost and sea water.
Liquid‐liquid equilibria of binary polymer blends: molecular thermodynamic approach
Authors: Chang Bong Ho , Bae Young Chan
Published: August 2003

We extended and simplified the modified double‐lattice model to binary polymer blend systems. The model has two model parameters, Cβ and Cγ. Those are not adjustable parameters but universal functions. In comparison with Ryu et al.'s simulation data for symmetric polymer blend with various chain lengths (r1 = r2 = 8, 20, 50, 100), Cγ is determined. Our results show that Cβ is negligible for symmetric polymer blend systems. The proposed model describes very well phase behaviors of weakly interacting polymer blend systems.
Modelling segmental dynamics in miscible polymer blends
Authors: Leroy Eric , Alegría Angel , Colmenero Juan
Published: August 2003

The complex thermorheological behaviour observed in miscible polymer blends is modelled by combining two existing theoretical approaches: The Thermal Concentration Fluctuation model (A. Zetsche, E.W. Fischer, Acta Polymer. 1994, 45, 168) and the Effective Concentration model (T.P. Lodge, T.C.B. McLeish, Macromolecules 2000, 33, 5278), giving rise to a simple model with only one adjustable parameter. This model is then tested in the case of two model blends allowing to show its abilities and limitations to describe how the respective segmental dynamics of lowest or highest Tg component are affected by blending.
Crystallization and structure formation in polymer blends with strong intermodular interactions: blends of poly(ethylene oxide) and styrene‐hydroxystyrene copolymers
Authors: Cho Jaedong , Xu Ruijian , Yeh Fengji , Hsiao Benjamin S. , Runt James
Published: August 2003

Time‐resolved synchrotron wide‐ and small‐angle X‐ray scattering experiments were used to investigate crystallization behavior and microstructure development of a nearly monodisperse poly(ethylene oxide) [PEO] (Mw = 53,500), and its melt‐miscible blends with two fractionated styrene ‐ hydroxystyrene random copolymers [SHS]. PEO crystallization rates decrease significantly in the presence of the melt‐miscible SHS copolymers. All low and high molecular weight SHS blends exhibit a crystallization process at relatively short times characterized by large Avrami exponents (n), followed by a dominant process with n near that of neat PEO. A model for the crystallization of these blends is proposed.
Shear influence on the phase behavior of systems containing a homopolymer A and a block copolymer AB
Authors: Madbouly Samy A.
Published: August 2003

Cloud point temperatures (Tcp) and crystallization temperatures (Tl/s) of the ternary system tetrahydronaphthalene/poly(ethylene oxide)/poly(dimethyl siloxane‐b‐ethylene oxide) have been measured at different constant shear rates using a rheo‐optical device and an advanced rheometer. The cloud points temperatures (UCST‐type phase diagram) are reduced by several degrees as the system flows; i.e. the shear can suppress the phase separation and enlarge the homogenous region. The crystallization kinetics of PEO in the ternary mixtures has been investigated isothermally and non‐isothermally at quiescent state and under shear. The shear could strongly enhance the crystallization i.e. the (Tl/s) shifts to higher temperatures and the induction time, t0 (the time needs for the onset of crystallization) substantially decreases with increasing shear rate during the non‐isothermal and isothermal crystallization processes, respectively. The isothermal crystallization kinetics at quiescent state and at different shear rates was analyzed on the bases of Avrami approach. The Avrami exponent which provides qualitative information about the nature of the nucleation and growth process, was found to be shear rate and temperature dependent. The Avrami exponent increased from ∼3 at the quiescent state to as large as 9 at &&ggr;dot; = 100 s−1.
Detection of co‐continuous structures in SAN/PA6 blends by different methods
Authors: Pötschke Petra , Paul Donald R.
Published: August 2003

This paper describes the 70/30 wt% composition of SAN/PA6 blends having different types of morphology, namely PA6 dispersed in SAN, a co‐continuous structures of PA6 and SAN, and a “mixed structure” which exhibits PA6 particles in SAN which themselves form the matrix for smaller SAN particles. These morphologies were achieved by using different processing conditions during extrusion blending in a twin screw extruder, especially variation in the screw speed and by injection molding. Morphological analysis using SEM and TEM, solubility experiments, DMA, and oscillatory rheometry are presented. These methods were shown to be able to distinguish between the different types of morphology. In addition, DSC was used to detect the PA6 crystallization behavior.
Interfacially induced additional damping peaks in dynamic mechanical spectra – micromechanical transitions in multipolymeric materials
Authors: Colombini Didier , Maurer Frans H.J.
Published: August 2003

The viscoelastic properties of several hypothetical multiphase polymeric materials were investigated in relation to their phase‐property dependencies and microstructures. Theoretical mechanical considerations based on the self‐consistent interlayer model were performed to point out that specific geometrical arrangements into phases of a set of properties of the pure constituents can lead to interfacially induced damping peaks in dynamic mechanical spectra (DMS). Such additional contributions in DMS were referred to micromechanical transitions to distinguish them from ordinary molecular transitions.
Blends of isotactic polypropylenes and a plastomer: crystallization and viscoelastic behavior
Authors: Cerrada Maria L. , Prieto Oscar , Pereña José M. , Benavente Rosario , Pérez Ernesto
Published: August 2003

Blends covering the entire range of compositions of a metallocenic ethylene‐1‐octene, CEO, copolymer and two conventional isotactic polypropylenes, iPP, of different molecular weights have been prepared, analyzing the effect of composition and molecular weight on the crystallization (studied by DSC and X‐ray diffraction) and viscoelastic behavior (DMTA). It was found that those blends rich in the iPP component show a behavior practically coincident with the weighted addition of the two components. On the contrary, significant deviations were found for the blends where the CEO copolymer is the major component. These deviations are considerably more important in the case of the blends with the iPP of higher molecular weight. Moreover, both components are not miscible, exhibiting the glass transitions of the two neat components. The area under the loss tangent curves provides a preliminary information about how the toughness is enhanced using this type of impact modifier, though it provokes a significant reduction of stiffness.
Reactive compatibilization of blends of PET and PP modified by GMA grafting
Authors: Pracella Mariano , Chionna Donatella
Published: August 2003

The melt radical grafting of glycidyl methacrylate (GMA) onto isotactic polypropylene (PP) was carried out in Brabender internal mixer and the influence of reaction procedure, radical initiator concentration and addition of co‐monomer (styrene) on the grafting efficiency was examined. The viscosity, the thermal behaviour and melt rheology of PP‐g‐GMA samples was then analysed as a function of grafted GMA content. Blends of poly(ethylene terephthalate) (PET) with PP and PP‐g‐GMA (5.2 wt% GMA), prepared in internal mixer, were characterised by SEM, DSC and melt viscosimetry. The morphological analysis of PET/PP‐g‐GMA blends (80/20, 50/50 w/w) pointed out a marked improvement of phase dispersion (with particle size of about 0.6 μm for 80/20 blend) and interfacial adhesion, as compared to non‐compatibilized PET/PP blend. The results of mixing torque and thermal analysis supported the occurrence of in‐situ compatibilization reaction between epoxy groups of GMA modified PP and carboxyl end‐groups of PET in the melt.
Reactively and physically compatibilized immiscible polymer blends: stability of the copolymer at the interface
Authors: Harrats Charef , Dedecker Kristof , Groeninckx Gabriel , Jérôme Robert
Published: August 2003

This paper reports on the interfacial behaviour of block and graft copolymers used as compatibilizers in immiscible polymer blends. A limited residence time of the copolymer at the interface has been shown in both reactive blending and blend compatibilization by preformed copolymers. Polystyrene (PS)/polyamide6 (PA6), polyphenylene oxide (PPO)/PA6 and polymethylmethacrylate (PMMA)/PA6 blends have been reactively compatibilized by a styrene‐maleic anhydride copolymer SMA. The extent of miscibility of SMA with PS, PPO and PMMA is a key criterion for the stability of the graft copolymer at the interface. For the first 10 to 15 minutes of mixing, the in situ formed copolymer is able to decrease the particle size of the dispersed phase and to prevent it from coalescencing. However, upon increasing mixing time, the copolymer leaves the interface which results in phase coalescence.

In PS/LDPE blends compatibilized by preformed PS/hydrogenated polybutadiene (hPB) block copolymers, a tapered diblock stabilizes efficiently a co‐continuous two‐phase morphology, in contrast to a triblock copolymer that was unable to prevent phase coarsening during annealing at 180°C for 150 minutes.
Morphology of reactive PP/PS blends with hyperbranched polymers
Authors: Pionteck Jürgen , Pötschke Petra , Proske Norbert , Zhao Hanying , Malz Hauke , Beyerlein Detlev , Schulze Ulrich , Voit Brigitte
Published: August 2003

To study the efficiency of different mechanism for reactive compatibilization of polypropylene/polystyrene (PP/PS) blends main chain or terminal functionalized PP and terminal functionalized PS have been synthesized by different methods. While the in‐situ block and graft copolymer formation results in finer phase morphologies compared to the corresponding non‐reactive blends, the morphology development in the ternary blend system PP/PS + HBP (hyperbranched polymer) is a very complex process. HBP with carboxylic acid endgroups reacts preferably with the reactive sites of the oxazoline functionalized PS (PS‐Ox) and locates mainly within the dispersed PS‐Ox phase. A bimodal size distribution of the PS‐Ox particles within the oxazoline modified PP (PP‐Ox) matrix phase is observed with big PS‐Ox particles (containing the HBP as dispersed phase) and small PS‐Ox particles similar in size like the unimodal distributed particles in the non‐reactive PP‐Ox/PS‐Ox blends. Factors influencing the morphology are discussed.
Compatibilized blends of thermoplastic polyurethane (TPU) and polypropylene
Authors: Lu Qi‐Wei , Macosko Christopher W. , Horrion Jacques
Published: August 2003

Compatibilized blends of thermoplastic polyurethane (TPU) and polypropylene (PP) were developed using amine (primary or secondary) functionalized PP's (PP‐g‐NH2 or PP‐g‐NHR). The strategy of reactive compatibilization is based on fast reactions between amine functional groups and urethane linkages or traces of free isocyanates released by thermal degradation of TPU. Excellent compatibilization between TPU and PP was confirmed by rheological, morphological, and mechanical properties. Much finer domain size, higher interfacial adhesion, and more stable morphologies were clearly observed by scanning electron microscopy. Significant improvements in the overall mechanical properties (tensile, tear, abrasion) imply significantly more reaction between TPU and PP phases in the two TPU/PP blends containing PP‐g‐NH2 or PP‐g‐NHR than a TPU/PP blend using PP‐g‐MA as a compatibilizing agent.
Biodegradable compositions by reactive processing of aliphatic polyester/polysaccharide blends
Authors: Dubois Philippe , Narayan Ramani
Published: August 2003

Commercially available biodegradable aliphatic polyesters, i.e., high molecular weight poly(ϵ‐caprolactone) (PCL) and polylactide (PLA), were melt blended with a well‐known natural and biodegradable polysaccharide: starch either as corn starch granules or as thermoplastic corn starch after plasticization with glycerol. Conventional melt blending yielded compositions with poor mechanical performances as a result of lack of interfacial adhesion between the rather hydrophobic polyester matrix and the highly hydrophilic and moisture sensitive starch phase. Interface compatibilization was achieved via two different strategies depending on the nature of the polyester chains. In case of PLA/starch compositions, PLA chains were grafted with maleic anhydride through a free radical reaction conducted by reactive extrusion. The maleic anhydride‐grafted PLA chains (MAG‐PLA) allowed for reinforcing the interfacial adhesion with granular starch as attested by TEM of cryofracture surface. As far as PCL/starch blends were concerned, the compatibilization was achieved via the interfacial localization of amphiphilic graft copolymers formed by grafting of PCL chains onto a polysaccharide backbone such as dextran. The PCL‐grafted polysaccharide copolymers were synthesized by controlled ring‐opening polymerization of ϵ‐caprolactone proceeding via a coordination‐insertion mechanism. These compatibilized PCL/starch compositions displayed much improved mechanical properties as determined by tensile testing as well as a much more rapid biodegradation as measured by composting testing.
Solvent activity changes and phase separation during crosslinking of coating films
Authors: Dušková‐Smrčková Miroslava , Dušek Karel , Vlasák Petr
Published: August 2003

Changes in solvent activity and thermodynamic stability of a system undergoing crosslinking in the presence of a solvent are modeled by combination of branching theory with thermodynamics of polymer solutions and swelling of a crosslinked polymer. The system is considered as a quasiternary one in which the solvent, polydisperse soluble polymer (sol) and crosslinked network, respectively, represent the components. Crosslinking brings about growth of polymer structures but also changes in polymer‐solvent interactions. The results are compared with onset of phase separation and changes in evaporation rates from films formed from a hydroxy‐functional star oligomer and triisocyanate.