bluuebunny/crossref_metadata_2025 huggingface dataset:
β-Arrestin2-Mediated Internalization of Mammalian Odorant Receptors
Authors: Mashukova Anastasia , Spehr Marc , Hatt Hanns , Neuhaus Eva M.
Published: September 2006

Odorant receptors comprise the biggest subfamily of G-protein-coupled receptors. Although the endocytic mechanisms of other G-protein-coupled receptors have been characterized extensively, almost nothing is known about the intracellular trafficking of odorant receptors. The present study describes the endocytic pathway of mammalian odorant receptors, which bind β-arrestin2 with high affinity and are internalized via a clathrin-dependent mechanism. After prolonged odorant exposure, receptors are not targeted to lysosomal degradation but accumulate in recycling endosomes. Odorant-induced odorant receptor desensitization is promoted by cAMP-dependent protein kinase A phosphorylation and is dependent on serine and threonine residues within the third intracellular loop of the receptor. Moreover, β-arrestin2 is redistributed into the dendritic knobs of mouse olfactory receptor neurons after treatment with a complex odorant mixture. Prolonged odorant exposure resulted in accumulation of β-arrestin2 in intracellular vesicles. Adaptation of olfactory receptor neurons to odorants can be abolished by the inhibition of clathrin-mediated endocytosis, showing the physiological relevance of the here described mechanism of odorant receptor desensitization. A better understanding of odorant receptor trafficking and additional insight into the molecular determinants underlying the interactions of odorant receptors with β-arrestin2 and other trafficking proteins will therefore be important to fully understand the mechanisms of adaptation and sensitization in the olfactory epithelium.
Vestibular Hair Bundles Control pH with (Na+, K+)/H+Exchangers NHE6 and NHE9
Authors: Hill Jennifer K. , Brett Christopher L. , Chyou Anthony , Kallay Laura M. , Sakaguchi Masao , Rao Rajini , Gillespie Peter G.
Published: September 2006

In hair cells of the inner ear, robust Ca2+/H+exchange mediated by plasma-membrane Ca2+-ATPase would rapidly acidify mechanically sensitive hair bundles without efficient removal of H+. We found that, whereas the basolateral membrane of vestibular hair cells from the frog saccule extrudes H+via an Na+-dependent mechanism, bundles rapidly remove H+in the absence of Na+and HCO3−, even when the soma is acidified. K+was fully effective and sufficient for H+removal; in contrast, Rb+failed to support pH recovery. Na+/H+-exchanger isoform 1 (NHE1) was present on hair-cell soma membranes and was likely responsible for Na+-dependent H+extrusion. NHE6 and NHE9 are organellar isoforms that can appear transiently on plasma membranes and have been proposed to mediate K+/H+exchange. We identified NHE6 in a subset of hair bundles; NHE9 was present in all bundles. Heterologous expression of these isoforms in yeast strains lacking endogenous exchangers conferred pH-dependent tolerance to high levels of KCl and NaCl. NHE9 preferred cations in the order K+, Na+≫ Rb+, consistent with the relative efficacies of these ions in promoting pH recovery in hair bundles. Electroneutral K+/H+exchange, which we propose is performed by NHE9 in hair bundles, exploits the high-K+endolymph, responds only to pH imbalance across the bundle membrane, is unaffected by the +80 mV endocochlear potential, and uses mechanisms already present in the ear for K+recycling. This mechanism allows the hair cell to remove H+generated by Ca2+pumping without ATP hydrolysis in the cell.
Academic Disqualification and Persistence to Graduation by Financial Aid Category and Academic Ability
Authors: Wessel Roger D. , Bell Carolyn L. , McPherson John D. , Costello Michael T. , Jones Jim A.
Published: September 2006

In this longitudinal study of 21,243 students, the academic disqualification and persistence to graduation by financial aid category and academic ability were studied. Students who had greater financial need disqualified at higher rates and persisted to graduation at lower rates. However, when financial aid categories were stratified by academic ability, academic ability was a better indicator of disqualification and persistence to graduation than was financial aid category. These data may provide clues to determine where financial intervention with institutional need-based aid may be most beneficial and how programmatic interventions may be appropriate.
Commentary: The Pivotal Role of the Faculty in Propelling Student Persistence and Progress toward Degree Completion
Authors: Stevenson Joseph M. , Buchanan Debra A. , Sharpe Abby
Published: September 2006

Many constituencies of a college or university make contributions to student success and failure. Higher education research has focused on many contributors to college or university student success, including pre-college preparation, transition or orientation programs, academic rigor, and academic and social support systems to name a few. Our observation is that the potential impact of one group—faculty—on student success far outweighs all others. Because student success is ultimately determined by their persistence to graduation, and student mastery of academic content determines their persistence and graduation, and faculty determine the extent to which mastery of courses has occurred, faculty are vital to student success. The authors recommend action research as a tool for faculty to assess the extent of their impact on student success (i.e., learning, persistence, and graduation).
Depression Case Finding in Primary Care: A Method for the Mandates
Authors: Nease Donald E. , Klinkman Michael S. , Aikens James E.
Published: September 2006

The current mandates for depression screening in primary care create a dilemma for clinicians. How should screening be implemented in the face of limited evidence for sustainable strategies for effective depression monitoring and management in primary care. In this article we review the issues surrounding primary care depression screening, and develop the argument for a case-finding strategy that includes careful choice of a single instrument, focused identification of high-risk patients, and systematic monitoring of outcomes. We believe this is a sustainable method that primary care clinicians can implement to address the spirit of current depression screening mandates.
Assessment of Depressive Symptoms in Japanese School Children and Adolescents Using the Birleson Depression Self-Rating Scale
Authors: Denda Kenzo , Kako Yuki , Kitagawa Nobuki , Koyama Tsukasa
Published: September 2006

Objective:

The aim of this study was to investigate the prevalence of depressive symptoms in children and adolescents in the general Japanese population using a depression self-rating scale and determine whether this prevalence varies according to age, gender, or region.

Method:

The Birleson Depression Self-Rating Scale for children (DSRS) was used to examine the extent to which depressive tendencies were present among 2,453 elementary and middle-school children (6 to 15 years old) in two cities in Japan.

Results:

The mean DSRS score was high at 8.75 + 5.66. A significant increase in score was observed with increasing age. There were no significant differences between regions. Using a DSRS cutoff score of 15 points as a risk of depression, the scores of 14.9% of the subjects exceeded the cutoff.

Conclusions:

As determined using the DSRS, a high proportion of Japanese children and adolescents have depressive tendencies.
Compliance and Coping Potential of Cancer Patients Treated in Liaison-Consultation Psychiatry
Authors: Grube Michael
Published: September 2006

Objective:

To investigate the impact of psychiatric illness, aggression, and other covarying variables on the compliance and coping potential of cancer patients treated in liaison-consultation psychiatry.

Methods:

The study involves 270 cancer patients who were admitted to the oncology ward for diagnosis and treatment. Each patient took part in a psychiatric consultation. We used the Transplant Evaluation Rating Scale (TERS), which provides a system for differentially recording the patient's compliance and coping potential (total score for the TERS items 3–10). Following standardization using the basic psychooncological documentation (PO-BADO), the demographic variables were recorded. We also identified the internal processes which each patient used to deal with the disease using criteria established by Kübler-Ross as well as the phases of cancer experience according to Fawzy.

Results:

Twenty-three variables were checked for their relationship to the coping and compliance potential. For 13 of these, the Mann-Whitney U-test or Spearmann-Rank correlation calculated exceeded the required Bonferroni-adjusted significance level. The calculation of an ordinal regression model containing these significant single variables showed that the following variables are associated with a lower compliance and coping potential according to their estimate (Beta-value): aggression as the dominant form of dealing internally with cancer (Kübler-Ross), pre-existing DSM IV Axis 1 psychiatric disorders, carcinoma-induced psychiatric disorders, necessity of treatment with neuroleptics and male gender. Acceptance as the dominant form of dealing internally with cancer (Kübler-Ross) is strongly associated with a higher compliance and coping potential.

Conclusion:

The results show that the compliance and coping potential of oncological in-patients can be comprehensively described by the Transplant Evaluation Rating Scale. The instruments of measurement used in the study are also useful for describing risk factors associated with low levels of compliance and coping potential.
Role of Dissociation in “False Drug Allergy”
Authors: Rodriguez-Cano Teresa , Beato-Fernandez Luis , Galindo-Bonilla Pedro
Published: September 2006

Objective:

The aim of the present study was to analyze the influence of dissociation on the “false allergy” phenomenon.

Method:

Fifty-five individuals (11 males and 44 females) who consecutively presented for the study of their suspected drug allergy were assessed.

Results:

After the challenge test, false allergy was found in 39.3% and placebo positive response in 12.5% of the patients. Seven patients (12.5%) scored above the cut-off point of 20 on the Dissociative Experiences Scale (DES), and 5 out of this group (71.4%) fit in the “false allergy” group. Pathological scores on the DES were associated with the diagnosis of “false allergy” (OR = 9.583, 95% CI = 1.002, 91.621). The effect of age, gender, and other psychopathological variables was controlled.

Conclusions:

High levels of dissociation might predispose to false drug allergy, which could complicate pharmacological treatment and therefore increase the patient's complaints and demands for medical attention.
The Impact of Remediation on Persistence of Under-Prepared College Students
Authors: Kreysa Peter G.
Published: September 2006

This study examined the influence of individual attributes, high school experience, and college experience upon persistence for remedial and non-remedial students. The subjects were 438 first-time true freshmen who graduated from a large private university on the West Coast. In addition to finding that remedial and non-remedial students did not differ with respect to graduation rates, the variables associated with declared major and changing majors were found to influence persisters and leavers in differing ways.
Wastewater Treatment
Authors: Eckenfelder W. Wesley ,   Updated by Staff
Published: September 2006

There is a scarcity of safe and good quality water at present and this problem will become more prevalent in the future. Sewage is the spent water supply of a community. Treatment of these spent waters (wastewater) is the focus of this article. Because of large equipment and land requirements, capital costs for wastewater‐treatment plants are high. A collection system that conveys both sanitary and storm flows must be designed to deal with high peak flows at a treatment plant.

Wastewater treatment technologies differ from each other in terms of their principles, scope of application, speed, and economy. Waste treatments begins with minimization of wastes as a primary measures and then is followed by physical, chemical, electrical, thermal, and biological treatments. All of these options are discussed. Tertiary, or advanced, treatments convert water processed by the above technologies into good quality water that can be used for different purposes such as drinking, industrial, and medicinal uses. Alternative biological processes include lagoon and aerated lagoons, activated sludge, fixed‐film processes, rotating biological contactors, anaerobic, and aerobic treatments. Managing the removed pollutants (sludge) is also detailed. Newer technologies for wastewater treatment are addressed, eg, ultrasonic radiation, ionizing radiation, conducting polymers, use of zeolites. Storm‐water control is an important issue and EPA permitting regulations for control are given. Other disposal considerations that are not based on sewers include septic tanks, package units, and boat waste. Health and safety are also discussed.
Waxes
Authors: Leray Claude
Published: September 2006

A review of waxes is provided, including classification, source, composition, production, testing, and applications. Waxes are generally classified according to source, such as natural waxes derived from animals or vegetables; mineral waxes derived from petroleum, coal, and peat; and synthetic waxes derived through polymerization of feed stocks, such as ethylene, methylene, and α‐olefins. The composition varies widely among the different classifications. Most of the natural waxes are mixtures with long‐chain alcohols, long‐chain carboxylic acids, and long‐chain esters as the major constituents. Waxes derived from coal and peat are similar, while the petroleum waxes consist almost exclusively of long‐chain hydrocarbons. Petroleum‐derived waxes are produced in massive quantities throughout the world. The synthetic waxes are generally low molecular weight polymers, with ethene polymers being the largest volume product. Since all waxes are fairly complex mixtures, physical properties are often used to describe the products. Uses vary from consumer products, such as chewing gum, cosmetics, and candles, to industrial applications, such as hot‐melt adhesives for carton sealing, flow modifier for plastic resins, and process additive for suspension polymerization.
Microfluidic modeling and design for continuous flow in electrokinetic mixing‐reaction channels
Authors: He Xiang , Hauan Steinar
Published: September 2006

Advances in microfluidics have inspired novel designs of LoC systems with integrated functionality and improved thermal and mass‐transfer characteristics. As important functional subsystems of LoC, microfluidic reaction systems can significantly reduce the need for space, materials, and energy, and often have shorter response times. Iterative design studies require accurate and fast models for subsystems. Here, we present two PFR‐network‐based models and a method of lines model for reaction subsystems. These two models employ two different discretization methods to reduce the set of PDEs into a system of coupled ODEs. We use our model to analyze an example micro mixing‐reaction system. The results illustrate how reaction channel length and the electric potential difference influence the product yields and selectivities. These models are ready to be combined other subsystem models for the design of integrated LoC systems.
Polyelectrolyte complex membranes based on two anionic polysaccharides composed of sodium alginate and carrageenan: The effect of annealing on the separation of methanol/water mixtures
Authors: Kim Sang‐Gyun , Lee Ki‐Sub , Lee Kew‐Ho
Published: September 2006

Through the complexation of two anionic polysaccharide blends composed of sodium alginate and carrageenan with divalent calcium ions, polyelectrolyte complex membranes were prepared. The effects of annealing on the structure of the polyelectrolyte complex membranes and on their performance at removing water from a methanol mixture were investigated and discussed. The annealed membranes exhibited a change in their crystallinity. The change was due to a rearrangement of polymer chains, which was induced by a deformation of the chelate structure and intramolecular or intermolecular interactions between the polysaccharides. Because of the effects of annealing on the resulting membranes, water components almost penetrated the membranes to the permeate side in the vapor permeation process. Moreover, the membrane performances were gradually enhanced as the operating temperature increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5781–5788, 2006
Effect of porosigen on the swelling behavior and drug release of porous N‐isopropylacrylamide/poly(ethylene glycol) monomethylether acrylate copolymeric hydrogels
Authors: Lee Wen‐Fu , Lin Yu‐Hung
Published: September 2006

A series of porous thermoreversible hydrogels were prepared from N‐isopropylacrylamide (90 mol %) and poly(ethylene glycol) methylether acrylate (10 mol %), which was derived from poly(ethylene glycol) monomethylether, N,N′‐methylenebisacrylamide, and porosigen, or poly (ethylene glycol) (PEG) with different molecular weights (MWs). The influence of pore volume in the gel on the physical properties, swelling kinetics, and solute permeation from these porous gels was investigated. The results show that the surface areas, pore volumes, and equilibrium swelling ratios for the porous gels increased with increasing MW of PEG, but the shear moduli and effective crosslinking densities decreased with increasing MW of PEG. The results from the dynamic swelling kinetics show that the transport mechanism was non‐Fickian. The diffusion coefficients of water penetrating into the gels increased with increasing pore volume of the gels. In addition, we also studied solute permeation through the porous gel controlled by temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5490–5499, 2006
Synthesis and mesomorphic properties of side‐chain cholesteric liquid‐crystalline polymers containing menthyl groups
Authors: Du Bing‐Guang , Hu Jian‐She , Zhang Bao‐Yan , Xiao Lin‐Jiu , Wei Ke‐Qi
Published: September 2006

A series of new cholesteric liquid‐crystalline polysiloxanes (P1–P5) derived from menthyl groups were synthesized. The chemical structures of the monomers and polymers were characterized with Fourier transform infrared, 1H‐NMR, 13C‐NMR, and elemental analyses. The mesomorphic properties and thermal behavior were investigated with differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analysis, and X‐ray diffraction measurements. The influence of the polymer structure on the thermal behavior was discussed. The monomer diosgeninyl 4‐allyloxybenzoate exhibited a typical cholesteric oily‐streak texture and a focal‐conic texture. Polymers P1–P5 showed thermotropic liquid‐crystalline properties. P1 displayed a smectic fan‐shaped texture, P2–P5 showed a cholesteric Grandjean texture, and P6 and P7 did not show mesomorphic properties. The experimental results demonstrated that the glass‐transition temperature and the clearing temperature decreased, and the mesomorphic properties weakened with an increasing concentration of menthyl units. Moreover, P1–P5 exhibited wide mesophase temperature ranges and high thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5559–5565, 2006
Isothermal and nonisothermal melt crystallization kinetics of a novel poly(aryl ether ketone ether ketone ketone) containing a meta‐phenyl linkage
Authors: Qiu Zhaobin , Yang Wantai
Published: September 2006

The isothermal and nonisothermal melt crystallization kinetics of a novel poly(aryl ether ketone ether ketone ketone) containing a meta‐phenyl linkage (PEKEKmK) were studied by differential scanning calorimetry. The Avrami equation was used to analyze the isothermal crystallization kinetics of PEKEKmK. The crystallization mechanism did not change within the crystallization temperature range, but the crystallization rate decreased with an increase in the crystallization temperature. The equilibrium melting point, T, was determined to be 327°C according to the Hoffman–Weeks equation. Moreover, the nonisothermal crystallization kinetics of PEKEKmK was also investigated by the Avrami equation as modified by Jeziorny. It was found that the nonisothermal crystallization behavior of PEKEKmK could be described well by this method at various cooling rates, although the parameters n and Zc did not have the same clear physical meaning as for isothermal crystallization kinetics. The thermal properties and crystallization characteristics of PEKEKmK were compared with those of all‐para PEKEKK(T) and PEKEKK(T/I) with a T/I ratio of 1. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4775–4779, 2006
PP/LDPE blends produced by reactive processing. I. Grafting efficiency and rheological and high‐elastic properties of [PP/LDPE]‐g‐IA melts
Authors: Pesetskii S. S. , Jurkowski B. , Krivoguz Y. M. , Tomczyk T. , Makarenko O. A.
Published: September 2006

Itaconic acid (IA) was grafted onto polypropylene/low‐density polyethylene (PP/LDPE) blends. The ratio of polymeric components was varied from 100 : 0 to 0 : 100. The effect of the variation in the ratios of the components on grafting efficiency and concomitant side processes was studied. Grafting of IA (1 wt %) was initiated by 2,5‐dimethyl‐2,5‐di(tert‐butyl peroxy)‐hexane (0.3 wt %) and was carried out in an extruder reactor equipped with a dynamic mixer. An increase in the PP content of the blend led to a lower yield of the grafted product. With low concentrations of LDPE in the blend (up to 25 wt %), grafting efficiency was observed to increase, and this increase was greater in comparison with the additive rule. Between 25 and 99 wt % of LDPE in the blend, grafting efficiency rose monotonically with LDPE concentration. At or below an LDPE content of 25 wt %, the melt flow index (MFI) of [PP/LDPE]‐g‐IA would increase unlike with PP‐g‐IA systems. But a small quantity of PP (below 25 wt %) in the [PP/LDPE]‐g‐IA blends would result in a decreased MFI unlike with LDPE‐g‐IA. The dependence of swell index and melt strength on the ratio of polymeric components in [PP/LDPE]‐g‐IA blends also was investigated. ©2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5095–5104, 2006
Impacts of impregnation with boron compounds on surface roughness of woods and varnished surfaces
Authors: Örs Yalçın , Atar Musa , Keskin Hakan , Çolakoğlu Mustafa H.
Published: September 2006

This study determines the effects of the process of impregnation of boron compounds on the surface roughness of Oriental beech, Scotch pine, Oriental spruce, and Uludağ fir woods and varnished surfaces. For this purpose, samples are prepared according to ASTM D 358 and impregnated according to ASTM D 1413‐99 with a 5.5% solution of boric acid (Ba), borax (Bx), and Ba with Bx (Ba + Bx) and varnished with synthetic varnish (Sv) and water‐based varnish (Wb) in accordance with ASTM D 3023. The surface roughness is determined according to ISO 4287 and TS 930 standards. The results indicate that the surface roughness is the highest in Uludağ fir, Wb, and Bx and the lowest in Oriental spruce, Sv, and Ba + Bx. For the combination of wood, impregnation material, and varnish, the surface roughness is the highest in Oriental beech with Bx and Wb and the lowest in Scotch pine with Ba + Bx and Sv. The surface roughness is less in impregnated samples than unimpregnated samples and in impregnated and varnished samples than impregnated and unvarnished samples. According to these results, boron compounds decrease the surface roughness of varnishes and wood materials. Thus, impregnation of wood with boron compounds decreases the surface roughness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4952–4957, 2006
Biologically active polymers. IV. Synthesis and antimicrobial activity of tartaric acid polyamides
Authors: Kenawy El‐Refaie , Abdel‐Hay Fouad I. , Shahada Lamies , El‐Shanshoury Abd El‐Raheem R. , El‐Newehy Mohamed H.
Published: September 2006

New bactericidal polyamides with quaternary ammonium or phosphonium salts were prepared, and their antimicrobial activities were explored. The polyamides were synthesized by the polycondensation of diethyl‐l‐tartrate or chloromethylated diethyl‐l‐tartrate with ethylenediamine in dry absolute ethanol. The polyamides were modified to yield polymers with either quaternary ammonium or phosphonium salts. The polymers were characterized with elemental microanalysis and 1H‐NMR and IR spectra. The antimicrobial activity of the polymers bearing onium salts was studied against Gram‐negative bacteria (Escherichia coli, Pseudomones aeruginosa, Shigella sp., and Salmonella typhae), Gram‐positive bacteria (Bacillus subtilis and Bacillus cereus), and a fungus (Trichophytum rubrum) by the cut‐plug and viable‐cell‐count methods. Although all the polymers showed high antibacterial activity, some had no antifungal activity. The tributyl phosphonium salt of the polyamide was more effective against both Gram‐negative and Gram‐positive bacteria than the triethyl ammonium and triphenyl phosphonium salts of the polyamide. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4780–4790, 2006
ESR study of hydroxyl alkoxyamine (HMPAP) in DMF and tert‐butylbenzene
Authors: Yin Meizhen , Krause Tilo , Habicher Wolf D.
Published: September 2006

Hydroxyl alkoxyamine (HMPAP) in DMF and in tert‐butylbenzene with oxygen as a scavenger was studied with electron spin resonance spectroscopy. From kinetics studies performed at 120°C, it was found that the rate constant of CO bond homolysis was smaller in DMF than in tert‐butylbenzene. The difference in the behavior could be related to the formation of an activated six‐membered intermediate formed through intramolecular H‐bonding in tert‐butylbenzene and the disruption of H‐bonding in the polar solvent DMF. This led to alteration of the equilibrium constant between the alkoxyamine and the corresponding nitroxide and C‐centered radical in DMF and decreased initiating efficiency for the controlled/living radical polymerization using HMPAP as initiator. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4116–4120, 2006
Application of DMEU/SiO2 gel solution in the antiwrinkle finishing of cotton fabrics
Authors: Huang K. S. , Nien Y. H. , Hsiao K. C. , Chang Y. S.
Published: September 2006

In this experiment, cotton fabrics were treated by padding, drying, and curing with an antiwrinkle finishing reagent, dimethylolethylene urea (DMEU), in combination with different concentrations of tetraethoxysilane (TEOS) and isopropanol (IPA) at various volumes. The treated fabrics were studied to determine the effects of adding TEOS and IPA. They were also analyzed using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) methods to examine the binding between SiO2 and DMEU. The results showed that hydrogen bonds formed between SiO2 and DMEU. TEOS was found to improve the antiwrinkle properties, tensile strength retention, and yellowing of the treated fabrics, although their softness was slightly reduced. The solvent IPA was shown to decrease the tensile strength of treated fabrics, although it improved their antiwrinkle properties. We observed only one stage of pyrolysis in untreated cotton fabrics, whereas the treated fabrics showed two stages. In addition, the fabrics treated with TEOS showed improved heat resistance. Our findings demonstrated that cotton fabrics showed excellent antiwrinkle properties and high tensile strength, when treated with a finishing solution composed of DMEU, 3% TEOS, IPA and water, followed by predrying and curing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4136–4143, 2006
Blend films of O‐carboxymethyl chitosan and cellulose in N‐methylmorpholine‐N‐oxide monohydrate
Authors: Zhuang X. P. , Liu X. F.
Published: September 2006

To introduce N‐methylmorpholine‐N‐oxide (NMMO) process to prepare antibacterial lyocell fiber, the blend films of O‐carboxymethyl chitosan (O‐CMCS) and cellulose were prepared. O‐CMCS in aqueous suspension with particles having a surface mean diameter of 2.24 μm was blended with cellulose in NMMO hydrate. The blend films with different O‐CMCS content were prepared with the blend solutions. SEM confirmed that O‐CMCS remained within the cellulose film in the particle. The mechanical properties of the blend films show little increased value when O‐CMCS was less 5%; however, it decreased sharply when O‐CMCS was over 8%. Thus, the optimum O‐CMCS content may give a good combination of antibacterial action and mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4601–4605, 2006
Comparing reinforcement strategies for epoxy networks using reactive and non‐reactive fortifiers
Authors: Calzia Kevin J. , Forcum Anne , Lesser Alan J.
Published: September 2006

Improvements in physical, mechanical, and thermal properties of an epoxy network are made with the use of a unique class of molecules that reinforce the network at the molecular scale. These molecules are commonly referred to as antiplasticizers or fortifiers. In this contribution, two types of fortifiers are incorporated into the model epoxy network. One, dimethyl methylphosphonate, is a simple additive while the other, diethyl phosphoramidate, contains a reactive amine and is cured as part of the network. The two approaches provide some unique differences in the physical and mechanical properties of the networks. Several mechanisms of fortification are discussed and correlated to the observed properties. In addition, it is shown that the fortifiers improve the rheological characteristics of the epoxy resin and act as fire‐retardants in the cured network. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4606–4615, 2006
Post‐extrusion solid‐state polymerization of fully drawn polyester yarns
Authors: Agrawal Ashwini K. , Mhaisgawali Vilas T.
Published: September 2006

Post‐extrusion solid‐state polymerization (SSP) of a commercial fully drawn filament yarn (FDY) of poly(ethylene terephthalate) was carried out at 220°C, 230°C, and 240°C for a duration of 30 min to 2 h under inert atmosphere. Molecular weight of the solid‐state polymerized polyester filaments was increased from 1.67 × 104 gm/mol to a maximum of 2.61 × 104 gm/mole for the sample subjected to 240°C for 2 h. The kinetics of the SSP in the highly oriented crystalline FDY polyester filaments was investigated using an empirical relation between initial molecular weight and time of SSP and was found to be greatly enhanced, compared to amorphous unoriented polyester chips. Though the free annealing (i.e., under no tension) of samples at high temperature during solid‐state polymerization had a detrimental effect on the orientation of the FDY yarn, the simultaneous increase in the molecular weight compensated the loss in mechanical properties to a great extent. Application of tension during SSP was found to improve the mechanical properties of the SSP yarn by a small value. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5113–5122, 2006
Studies on blends of natural rubber and ethylene propylene diene rubber modified with phosphorylated cardanol prepolymer: Processability, physico‐mechanical properties, and morphology
Authors: Menon A. R. R. , Sonia T. A. , Sudha J. D.
Published: September 2006

The melt processability and physico‐mechanical properties of blends of natural rubber (NR) and ethylene propylene diene rubber (EPDM) containing different dosages (0–10 phr) of phosphorylated cardanol prepolymer (PCP) were studied in unfilled and china‐clay‐filled mixes. The plasticizing effect of PCP in the blends was evidenced by progressive reduction in power consumption of the mixing and activation energy for melt flow with an increase in the dosage of PCP. The PCP‐modified blend vulcanizates showed higher tensile properties and tear strength despite a decrease in the chemical crosslink density (CLD) index. This is presumably due to the formation of a crosslinked network structure of PCP with the rubbers and improved dispersion of the filler particles in the rubber matrix, as evidenced by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Thermogravimetric analysis showed an increase in thermal stability of the blend vulcanizate in presence of 5 phr of PCP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5123–5130, 2006
Dynamic mechanical properties in blends of poly(styrene‐b‐isoprene‐b‐styrene) with aromatic hydrocarbon resin
Authors: Wu Caiyun , Wu Guozhang , Wu Chifei
Published: September 2006

The damping properties in blends of poly(styrene‐b‐isoprene‐b‐styrene) (SIS) and hydrogenated aromatic hydrocarbon (C9) resin were investigated by dynamic mechanical analysis. SIS exhibited two independent peaks of loss factor (tan δ) corresponding to the glass transition of polyisoprene (PI) and polystyrene (PS) segments, respectively. The addition of hydrogenated C9 resin had a positive impact on the damping of SIS. With the increasing softening point and content of the resin, the main tan δ peak shifted to higher temperatures and the useful damping temperature range was broadened. Addition of mica or PS was found to widen the effective damping range evidently in the high‐temperature region, especially when PS was mixed in the solid state. It was concluded that the dispersed PS domains played a role of reinforcing fillers at low temperatures and served as a polymer component with a tan δ peak due to its glass transition at the high temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4157–4164, 2006
Interfacial studies on the surface modified aramid fiber reinforced epoxy composites
Authors: Wu Ju , Cheng Xian‐Hua
Published: September 2006

In this work, solutions of rare earth modifier (RES) and epoxy chloropropane (ECP) grafting modification method were used for the surface treatment of aramid fiber. The effect of chemical treatment on aramid fiber has been studied in a composite system. The surface characteristics of aramid fibers were characterized by Fourier transform infrared spectroscopy (FTIR). The interfacial properties of aramid/epoxy composites were investigated by means of the single fiber pull‐out tests. The mechanical properties of the aramid/epoxy composites were studied by interlaminar shear strength (ILSS). As a result, it was found that RES surface treatment is superior to ECP grafting treatment in promoting the interfacial adhesion between aramid fiber and epoxy matrix, resulting in the improved mechanical properties of the composites. Meanwhile, the tensile strengths of single fibers were almost not affected by RES treatment. This was probably due to the presence of reactive functional groups on the aramid fiber surface, leading to an increment of interfacial binding force between fibers and matrix in a composite system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4165–4170, 2006
Polymerization of halogenated anilines by plasma
Authors: Olayo M. G. , Enríquez M. A. , Cruz G. J. , Morales J. , Olayo R.
Published: September 2006

This work presents an experimental study about the electric conductivity in polyanilines synthesized by plasma obtained from halogenated anilines in which chlorine or iodine atoms are bonded in meta position to the aniline rings. The objective is to study the enhancement of the electric conductivity of these structures due to the addition of electronegative atoms to the polymeric chains. The results show that the halogenated anilines produce polymers with an electric conductivity up to eight orders of magnitude higher than those of the undoped polyanilines, reaching ∼10−4 S/cm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4682–4689, 2006
Influence of curing agent and compatibilizer on the physicomechanical properties of polypropylene/nitrile butadiene rubber blends investigated by positron annihilation lifetime technique
Authors: Soares B. G. , Almeida M. S. M. , Deepa Urs M. V. , Kumaraswamy G. N. , Ranganathaiah C. , Siddaramaiah  , Mauler R.
Published: September 2006

A series of thermoplastic vulcanizates of polypropylene (PP)/nitrile butadiene rubber (NBR) (50/50) have been prepared by melt‐mixing method, using phenolic resin/SnCl2 as the curing system and maleic anhydride‐functionalized PP (PP‐g‐MA) and carboxylated NBR (NBRE‐RCOOH) as the compatibilizing system. Triethylenetetramine was also employed to promote the reaction between the functionalized polymers. The effects of curing agent and compatibilizer on the mechanical and morphological properties have been studied. A novel technique based on positron annihilation lifetime spectroscopy has been used to measure the free volume parameters of these systems. The positron results showed minimum free volume size and free volume fraction at 5.0% of the curing agent suggesting some crosslinking in the rubber phase. The reduction in free volume holes at 2.5% of the compatibilizer is interpreted as improvement in the interfacial adhesion between the components of the blend. The observed variation of free volume fraction is opposite to the tensile strength and exhibits the correlation that, lesser the free volume more is the tensile strength at 2.5% of the compatibilizer in the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4672–4681, 2006
Microwave‐assisted preparation of temperature sensitive poly(N‐isopropylacrylamide) hydrogels in poly(ethylene oxide)‐600
Authors: Shi Shaohua , Liu Lijian
Published: September 2006

In this article, a series of poly(N‐isopropylacrylamide) (PNIPAM)‐based hydrogels were prepared under microwave irradiation using poly(ethylene oxide)‐600 (PEO‐600) as reaction medium and microwave‐absorbing agent as well as pore‐forming agent. All of the temperature measurements, gel fractions, and FTIR analyses proved that the PNIPAM hydrogels were successfully synthesized. Within 1 min, the PNIPAM hydrogel with a 98% yield was obtained under microwave irradiation. The PNIPAM hydrogels thus prepared exhibited controllable properties such as pore size, equilibrium swelling ratios, and swelling/deswelling rates when changing the feed weight ratios of monomer (N‐isopropylacrylamide, NIPAM) to PEO‐600. These properties are well adapted to the different requirements for their potential application in many fields such as biomedicine. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4177–4184, 2006
Effect of immobilized neutral protease on the preparation and physicochemical properties of low molecular weight chitosan and chito‐oligomers
Authors: Li Jin , Du Yu Min , Liang Hong Bo , Yao Ping Jia , Wei Yuan An
Published: September 2006

Neutral protease was immobilized on glutaraldehyde‐pretreated N‐succinyl chitosan hydrogel beads and the biocatalyst obtained was used for the preparation of low molecular weight chitosan and chito‐oligomers with molecular weight of 1.9–23.5 kDa from commercial chitosan. Factors affecting the chitinolytic hydrolysis were described. The degradation was monitored by gel permeation chromatography. The structure of degraded chitosan was characterized by Fourier transform infrared, X‐ray diffraction and liquid chromatography‐mass spectrometry. Immobilized neutral protease showed optimal depolymerization at pH 5.7 and 50°C. The degree of deacetylation of the hydrolysates did not change compared to that of the initial chitosan. The decrease of molecular weight led to transformation of crystal structure but the chemical structures of residues were not modified. The degree of polymerization of chito‐oligomers was mainly from 3 to 8. The method allows cyclic procedures of immobilized enzyme and N‐succinyl chitosan support utilization, and is suitable for a large‐scale production of the low molecular weight chitosan and chito‐oligomers free of protein admixtures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4185–4193, 2006
Interfacial adhesion through maleic anhydride grafting of EPDM in PP/EPDM blend
Authors: Purnima D. , Maiti S. N. , Gupta A. K.
Published: September 2006

This paper presents a study of interface modification effect through the use of maleic anhydride (MAH) grafting on one of the component polymers of the binary blend. The system used is binary blend of polypropylene (PP) and the elastomer EPDM (copolymer of ethylene–propylene–diene monomer). Two sets of the blend (i) PP/EPDM binary blend and (ii) PP/EPDM‐g‐MAH binary blend at constant degree of grafting (i.e., EPDM : MAH ratio) and at varying blending ratios were studied and compared for the properties and structure development. Results are discussed to illustrate the effect of interfacial modification due to presence of MAH by comparing the data of mechanical properties and crystallization behavior for the two sets of the binary blend at identical blending ratios, as well as to study the trends of variation of properties with blending ratio for each individual set of the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5528–5532, 2006
Effect of the interface with solid on the interfacial region in the blends of linear polymers formed in situ
Authors: Lipatov Yu. S. , Kosyanchuk L. F. , Yarovaya N. V.
Published: September 2006

Blends of polyurethane and poly (methyl methacrylate) of various compositions were synthesized in situ in presence of various amounts of nanoparticles (fumed silica). From thermo‐ physical measurements it was found that the reaction is accompanied by the phase separation and evolution of two phases. The temperature transitions in the systems and their positions depend on the blend composition and on the filler amount. Using scanning differential calorimetry, the fraction of an intermediate region between two main phases has been estimated from the changing of heat capacity increments. It was observed that in filled polymer blends in the temperature region between two main relaxation transitions, there appears the third transition. This transition is supposed to be the result of the formation of adsorption layer at the interface with solid. The appearance of such an intermediate regions increases essentially the total fraction of an interfacial region in the system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4646–4651, 2006
Effects of polydimethylsiloxane concentration on properties of polyurethane/polydimethylsiloxane hybrid dispersions
Authors: Fei Guiqiang , Shen Yiding , Wang Haihua , Shen Yue
Published: September 2006

A series of waterborne polyurethane (WPU) derived from isophorone isocyanate and poly(tetramethylene glycol) were modified by hydroxyl‐terminated polydimethylsiloxane (HPMS). The solutions were then cast into films named as PUHS. Rheological behavior of the emulsions were studied using Rheometer and morphology was studied with transmission electron microscope. Meanwhile, the casting films were prepared from the WPU/HPMS hybrid dispersions, and their glass transition behavior, miscibility, water resistance, and medium resistance were studied with differential scanning calorimeter (DSC), wide‐angle X‐ray diffraction (WAXD), and so on. The results revealed that the emulsions' particle size decreases with increasing HPMS content and the particles are more easily affixed to each other when the HPMS content is more than 15%, and emulsions are endowed with pseudoplasticity and thixotropy. WAXD and DSC figures manifested that the casting films all exhibited a certain degree of miscibility. The degrees of crystallinity (xc) decreased with increasing HPMS content, and the PUHS films were almost amorphous. It is noticed that water and medium absorption increased in the HPMS/PU compared to pure PU, which demonstrate that the membrane surfaces have excellent water and chemical medium repellency. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5538–5544, 2006
Synthesis and characterization of new flame‐retardant poly(amide‐imide)s containing phosphine oxide and hydantoin moieties in the main chain
Authors: Faghihi Khalil
Published: September 2006

Six new flame‐retardant poly(amide‐imide)s (PAIs) 9a–f with high inherent viscosities containing phosphine oxide and hydantoin moieties in main chain were synthesized from the polycondensation reaction of N,N′‐(3,3′‐diphenylphenylphosphine oxide) bistrimellitimide diacid chloride 7 with six hydantoin derivatives 8a–f by two different methods such as solution and microwave assisted polycondensation. Results showed that the microwave assisted polycondensation, by using a domestic microwave oven, proceeded rapidly, compared with solution polycondensation, and was completed in about 7–9 min. All of the obtained polymers were fully characterized by means of elemental analysis, viscosity measurements, solubility test, and FTIR spectroscopy. Thermal properties and flame retardant behavior of the PAIs 9a–f were investigated using thermal gravimetric analysis (TGA and DTG) and limited Oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers showed good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that these polymers are capable of exhibiting good flame retardant properties. These polymers can be potentially utilized in flame retardant thermoplastic materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5062–5071, 2006
Synthesis and characterization of dextran hydrogels prepared with chlor‐ and nitrogen‐containing crosslinkers
Authors: İmren Dilek , Gümüşderelioğlu Menemşe , Güner Ali
Published: September 2006

In this study, we have synthesized dextran hydrogels by the crosslinking reactions of dextran with some selective Cl‐, and N‐containing functional monomers, such as epichlorohydrin (ECH), N,N′‐methylenebisacrylamide (MBAm), and glutaraldehyde (GA). Crosslinking reactions were carried out in the basic aqueous solutions (2.8NNaOH) at 25–50°C. The optimum conditions for effective crosslinking, i.e., temperature, crosslinking time, and amount of crosslinker, were determined for each system. The hydrogel discs of 3 mm diameter and 1.5 mm thickness were subjected to a number of Tris‐buffer solutions of desired pH (2.0–9.0) at 37°C. Swelling kinetics of the hydrogels were evaluated with second–order swelling model. The pH‐dependent swelling of hydrogels was strongly influenced by the functional group of crosslinker and crosslinker content. While the hydrogels prepared with ECH and MBAm shows higher swelling ability at basic medium than that of acidic medium, GA‐containing hydrogels exhibited just the opposite behavior. Mesh sizes (ξ) and average molecular weights between crosslinks (Mc) were estimated from swelling data using the Flory‐Rehner theory. Characterization studies were completed by Fourier transform infrared spectroscopy and thermal gravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4213–4221, 2006
Aluminosilicate‐filled composites of PVA–PVP—An improved biodegradable polymeric material
Authors: Saha Nabanita , Ali S. K. Akbar , Kar Sritama , Saha Petr , Banthia Ajit K.
Published: September 2006

Poly(viny alcohol)–poly(vinyl pyrrolidone) biodegradable polymer blend was modified with aluminosilicate. Sample films containing 5, 10, 15, and 20 wt % filler were prepared by conventional solvent casting technique using glass plates as casting surfaces. The newly developed biodegradable composites are bright red, with magnetic properties due to the presence of iron compounds. Physical, chemical, and biodegradable properties of the films were studied with the conclusion that the presence of aluminosilicate affects the properties of the matrix and enhances biodegradability of the polymer composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4963–4970, 2006