bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequentially activated discrete modules appear as traveling waves in neuronal measurements with limited spatiotemporal sampling
Authors: Orsher Yuval , Rom Ariel , Perel Rotem , Lahini Yoav , Blinder Pablo , Shein-Idelson Mark
Published: March 2024

Numerous studies have identified traveling waves in the cortex and suggested they play important roles in brain processing. These waves are most often measured using macroscopic methods that are unable to assess the local spiking activity underlying wave dynamics. Here, we investigated the possibility that waves may not be traveling at the single neuron scale. We first show that sequentially activating two discrete brain areas can appear as traveling waves in EEG simulations. We next reproduce these results using an analytical model of two sequentially activated regions. Using this model, we were able to generate wave-like activity with variable directions, velocities, and spatial patterns, and to map the discriminability limits between traveling waves and modular sequential activations. Finally, we investigated the link between field potentials and single neuron excitability using large-scale measurements from turtle cortex ex vivo. We found that while field potentials exhibit wave-like dynamics, the underlying spiking activity was better described by consecutively activated spatially adjacent groups of neurons. Taken together, this study suggests caution when interpreting phase delay measurements as continuously propagating wavefronts in two different spatial scales. A careful distinction between modular and wave excitability profiles across scales will be critical for understanding the nature of cortical computations.
Identification and transcriptomic profiling of salinity stress response genes in colored wheat mutant
Authors: Hong Min Jeong , Ko Chan Seop , Kim Jin-Baek , Kim Dae Yeon
Published: March 2024

Background

Salinity is a major abiotic stress that prevents normal plant growth and development, ultimately reducing crop productivity. This study investigated the effects of salinity stress on two wheat lines: PL1 (wild type) and PL6 (mutant line generated through gamma irradiation of PL1).

Results

The salinity treatment was carried out with a solution consisting of a total volume of 200 mL containing 150 mM NaCl. Salinity stress negatively impacted germination and plant growth in both lines, but PL6 exhibited higher tolerance. PL6 showed lower Na+ accumulation and higher K+ levels, indicating better ion homeostasis. Genome-wide transcriptomic analysis revealed distinct gene expression patterns between PL1 and PL6 under salt stress, resulting in notable phenotypic differences. Gene ontology analysis revealed positive correlations between salt stress and defense response, glutathione metabolism, peroxidase activity, and reactive oxygen species metabolic processes, highlighting the importance of antioxidant activities in salt tolerance. Additionally, hormone-related genes, transcription factors, and protein kinases showed differential expression, suggesting their roles in the differential salt stress response. Enrichment of pathways related to flavonoid biosynthesis and secondary metabolite biosynthesis in PL6 may contribute to its enhanced antioxidant activities. Furthermore, differentially expressed genes associated with the circadian clock system, cytoskeleton organization, and cell wall organization shed light on the plant’s response to salt stress.

Conclusions

Understanding these mechanisms is crucial for developing stress-tolerant crop varieties, improving agricultural practices, and breeding salt-resistant crops to enhance global food production and address food security challenges.
TAKRA: AN INTEGRATIVE REVIEW ON ITS EFFICACY IN IRRITABLE BOWEL SYNDROME
Authors: Keshri Mayank Kumar , Prakash Shalini
Published: March 2024

In the quest for effective and holistic therapies for the growing burden of gastrointestinal illnesses, IBS has emerged as a major concern. This integrative review, "Takra: An integrative review on its efficacy in irritable bowel syndrome," examines whether Takra (buttermilk), a fermented dairy product, can treat IBS. The human gut, a dynamic ecology of microbes, is essential to health. New research has shown that gut health affects everything from immunity to mental health. IBS, a persistent functional gastrointestinal illness that causes abdominal pain and bloating and changes bowel patterns, burdens sufferers and healthcare systems worldwide. Takra (buttermilk or chaas) has a long history in traditional medicine, particularly in Ayurveda, which was used to treat digestive issues like Grahani roga (Malabsorption syndrome). Its fermentation process gives it probiotic characteristics, making it ideal for gastrointestinal ailments. This extensive analysis evaluates clinical and preclinical data to determine if Takra (buttermilk) can treat IBS. Historical use, mechanisms of action, clinical evidence, and safety are studied. The results of this review imply that Takra (buttermilk) may be a promising natural and culturally rooted IBS supplement. This article discusses Takra (buttermilk), the ancient elixir, and its potential to improve gut health, treat IBS, and improve the quality of life as the global healthcare landscape evolves towards integrative and holistic treatments.
A CASE STUDY ON RESTORING FACIAL SYMMETRY: AN AYURVEDIC APPROACH TO ARDITA (BELL’S PALSY)
Authors: Prabhu Pooja , Paradkar Hemant , Pal Subodh , Pathrikar Anaya , Kamat Nitin
Published: March 2024

The case study outlines the successful Ayurvedic management of Bell's palsy, referred to as Ardita in Ayurveda. The 46-year-old male patient presented with sudden onset drooping of the right upper eyelid, prominent right nasolabial fold, and dryness in the right eye after travelling. These symptoms are consistent with facial muscle weakness, which is characteristic of Bell's palsy. In Ayurveda, Ardita is correlated with the vitiation of Vata dosha, leading to facial distortion. The treatment approach adopted in this case was shamana chikitsa, a method focused on pacifying the aggravated dosha. Additionally, the Tarpana procedure, belonging to Netra-kriya-kalpana (ocular therapies), was employed along with mild ocular exercises. The shamana and Tarpana procedures were initiated from the first day of the treatment. After two weeks, there was a significant improvement in the gradation of Bell's palsy, resulting in a normal palpebral aperture of the eye. Notably, the treatment approach followed Ayurvedic principles and did not involve the use of oral steroids. This case study contributes to exploring and developing Ayurvedic treatment modalities for Bell's palsy. The successful outcome, without adverse effects, highlights the potential effectiveness of Ayurvedic interventions in managing facial muscle weakness. The emphasis on shamana and specific ocular therapies aligns with the holistic approach of Ayurveda, addressing the root cause of the condition and promoting overall well-being. In conclusion, this case study provides valuable insights into Ayurvedic management of Bell's palsy, showcasing the potential of traditional Ayurvedic principles and therapies in treating facial muscle weakness, enhancing confidence and preventing long-term facial damage.
Biodegradation of poly(L‐aspartic acid‐co‐valine) and its derivatives
Authors: Tang Guping , He Binbin
Published: July 2006

Biodegradable poly(L‐aspartic‐acid/valine) (PAV) was synthesized by thermal polycondensation. The molar ratios of aspartic acid/valine were 9 : 1, 8 : 2, 7 : 3, 6 : 4, and 5 : 5, respectively. The chemical structure of PAV was confirmed by 13C‐NMR, DSC, FTIR, X‐ray, and GPC measurements. The degradation of PAV was studied in PBS buffer solution (pH 7.4 and 8.2) and in aqueous solution with enzymatic hydrolysis in which papain and trypsine acted as catalyst. It showed that the biodegradation rate of PAV was increased when the content of valine in copolymer increased. 3‐Hydroproplamine was used in a succinimide ring‐open reaction to obtain hydrophilic products (PHPAV). Stability tests showed that humidity, light, and temperature had no remarkable effect on PHPAV, however, it could be degraded in base solution. Biocompatibility and hematological tests were investigated. No deaths were found in the mice treated with PHPAV solution up to a 7.5 g/kg dose. No differences in number of red cells and glutamic pyruvic and creatinuria transaminase activities were found between the experiment and the control groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 46–51, 2006
Effect of selected boroorganic compounds on thermal and heat properties of rigid polyurethane–polyisocyanurate foams
Authors: Czupryński Bogusław , Liszkowska Joanna , Paciorek‐Sadowska Joanna
Published: July 2006

The effects of three selected borates {tri(hydroxypropyl), tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)‐1‐methylethyl], tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)propyl]} on the heat and thermal properties of rigid polyurethane–polyisocyanurate foams was studied. Increasing the amount of tri(hydroxypropyl) borate and tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)propyl] borate in the foam composition from 0.1 to 0.4 chemical equivalents caused an increase in the softening point, the temperature of the first decrement of foam mass, the extrapolated temperature of the main decrement of the foam mass, and the temperature of the highest rate of the mass decrement. When tri[(3‐chloro‐2‐hydroxy‐1‐propoxy)‐1‐methylethyl] borate was added to the foam compositions, the softening point decreased but the temperatures characterizing their thermal resistance were higher in comparison with the standard foam. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 768–771, 2006
4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites: Preparation and properties
Authors: Lu Guotao , Huang Ying , Yan Yehai , Zhao Tong , Yu Yunzhao
Published: July 2006

4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites were prepared by the sol–gel process of tetrabutyl titanate in the presence of 4,4′‐bismaleimidodiphenyl methane modified novolak resin prepolymers with acetyl acetone as a stabilizer. These nanocomposite materials were characterized by Fourier transform infrared analysis, dynamical mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and field emission scanning electron microscopy. Nanometer titania particles were formed in the novolak resin matrix, and the average original particle size of the dispersed phase in the nanocomposites was less than 150 nm, but particle aggregates of larger size existed. The introduction of the titania inorganic phase with a nanoscale domain size did not improve the glass‐transition temperature of the nanocomposites but lowered the thermal resistance of the material because of the incomplete removal of acetyl acetone coordinated with tetrabutyl titanate, and it improved the modulus of the material at lower temperatures (<200°C) but lowered the modulus at higher temperatures (>250°C). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 52–57, 2006
Bound rubber in chlorobutyl compounds: Influence of filler type and storage time
Authors: Sridhar V. , Gupta B. R. , Tripathy D. K.
Published: July 2006

Bound rubber (BdR) is considered as a measure of the filler–polymer interaction in rubber compounds. The variation of the BdR content with storage time was studied in chlorobutyl compounds filled with fillers like carbon black, carbon–silica dual phase filler (CSDPf), silica, and nanoclays. The effect of the addition of a silane coupling agent on the BdR in carbon black and silica filled compounds was also studied. The BdR content increased with storage time in all compounds. The increase in BdR was higher during the initial 15 days of storage. Thereafter there was only a marginal increase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 715–720, 2006
Preparation and characterization of highly swelling smart grafted polymer networks of poly(vinyl alcohol) and poly(acrylic acid–co–acrylamide)
Authors: Shukla Sandeep , Bajpai A. K.
Published: July 2006

Smart grafted polymer networks comprising random copolymer of poly(acrylic acid‐co‐acrylamide) and polyvinyl alcohol and exhibiting extraordinary water imbibtion property were prepared by free radical polymerization method and characterized by Fourier Transform infrared spectroscopy, Ultra Violet spectroscopy, Environmental Scanning Electron Microscopy, Thermogravimetric Analysis, Differential Scanning Calorimetry, and X–ray Diffraction. The mesh size (ξ) and chain flexibility factor (α) of interpenetrating polymer networks were calculated for various grafted polymer network compositions and correlated with their water sorption capacity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 84–95, 2006
Flame‐retardant ABS resins from novel phenyl isocyanate blocked novolac phenols and triphenyl phosphate
Authors: Ji Youngyoun , Kim Jinhwan , Bae Jin‐Young
Published: July 2006

In an effort to prepare a novel novolac phenol (NP) based char former with good solubility, the hydroxyl functionalities of NP were blocked with phenyl isocyanate (PI) via a simple urethane‐forming reaction. The chemical structure and properties of the obtained novolac phenol–phenyl isocyanate adduct (NP–PI) were characterized with gel permeation chromatography, Fourier transform infrared spectroscopy, 1H‐NMR, and differential scanning calorimetry. Adducts of two kinds of NPs (molecular weights = 450 and 800) with PI were used as potential char formers for this study. Thus, a two‐component system using NP–PI as a char former and triphenyl phosphate (TPP) as a phosphorous‐based flame retardant was blended with ABS, and the thermal degradation behavior and flame retardance were examined as a function of the molar mass of NP–PI and the TPP/NP–PI ratio with thermogravimetric analysis and limiting oxygen index (LOI) testing. ABS compositions with no NP–PI were also prepared for comparison. The mixtures showed a synergistic effect between TPP and NP–PI on the flame‐retardance enhancement of ABS. Those containing the higher molar mass NP–PI adduct were the most flame retardant, and a LOI value as high as 41 was obtained. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 721–728, 2006
Pulverization of rubber using modified solid state shear extrusion process (SSSE)
Authors: Shahidi Nima , Arastoopour Hamid , Ivanov George
Published: July 2006

The challenge of reusing scrap rubber material is mainly due to its crosslinked/vulcanized structure, which prevents the material from melting and from being melt processed into new items. The most feasible recycling approach is believed to be a process in which the vulcanized rubber is first pulverized into a fine powder and then incorporated into new products. Solid state shear extrusion (SSSE), developed at Illinois Institute of Technology, is a process for continuous pulverization of rubber materials into a fine powder (Aratoopour, H. U.S. Pat. 5,704,555 (1998); Arastoopour, H.; Schocke, D. A.; Bernstein, B.; Bilgili, E. U.S. Pat. 5,904,885 (1999); Ivanov, G. Polym Eng Sci 2000, 40, 676). In this work, the design of the SSSE apparatus was modified to overcome heat generation due to pulverization and the limitation from the torque/feeding rate relation and, thus, to increase the efficiency of the process in the production of finer particles at higher throughput. The modification was achieved by separating the original process into the extrusion section and the pulverization section. The extrusion section is dedicated to convey material to the pulverization section, which consists of a cylindrical housing and a rotatable cylindrical element that rotates independent of the extruder's screw. The rotatable cylindrical element can be treaded or flightless. Both sections are connected with an adapter. This new approach to the design allowed us to apply a more efficient cooling system, capable of removing the heat of pulverization and, in turn, results in the production of finer rubber particles. Furthermore, separation of the conveying process from the pulverization process resulted in a reduction in extruder's torque and a significant increase in the throughput. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 119–127, 2006
Physico‐mechanical, dynamic mechanical, and swelling properties of sodium chloride filled chlorobutyl vulcanizates
Authors: Sridhar V. , Tripathy D. K.
Published: July 2006

The effect of addition of rigid, nonreinforcing, and noninteracting filler viz. finely ground NaCl in chlorobutyl vulcanizates on properties such as physicomechanical, dynamic mechanical, and swelling has been studied. The nonreinforcing effect of NaCl in the system was studied by Russel and Cunnenn analysis and Kraus plots. Mechanical measurements of stress and strain at the break of filled and unfilled samples showed no appreciable change in the mechanical behavior of the system. The dynamic mechanical analysis showed that there is no change at all in the glass transition temperature with addition of NaCl filler. The damping properties showed an increase with increase in filler loading because of the filler–filler friction. The swelling behavior of NaCl‐filled CIIR was studied for a period of 60 days in four different solvents of varying chemical energy potential viz. water, chloroform, acetone, and tetrahydrofuran (THF). The degree of swelling was found to increase continuously with time in water, which is a good solvent for the filler, and in THF, which is a good solvent for the polymer matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 707–714, 2006
Synthesis of crosslinked oxidized starch and its adsorption behavior for calcium ion
Authors: Chen Yanxiao , Wang Gongying
Published: July 2006

Cornstarch, after crosslinking with epichlorohydrin (4%, v/w, dry basis of the starch), was oxidized with hydrogen peroxide over the catalyst Cu(II). The newly synthesized products were applied to examine the calcium ion removal activity from water, under various conditions. Removal efficiency of calcium ion from aqueous solution increased proportionally with carboxyl content and the dose of crosslinked oxidized starch in the solution. Ionization of carboxyl groups in starch was necessary for the effective calcium removal. When the pH of the solution was adjusted below 4.0, the starch was no longer an effective calcium‐sequestering agent. Adsorption isotherm models were developed, wherein the best fit was obtained in the Langmuir model. Thermodynamic study indicated that the adsorption process was exothermic, and the enthalpy change (ΔHθ), the entropy change (ΔSθ), and free energy change (ΔGθ) of the adsorption process were calculated with adsorption isotherm data and basic thermodynamic relations. It was assessed that adsorption occurred by strong electrostatic interactions with the negative adsorption enthalpy (ΔHθ). The regeneration and reusability of oxidized starch were also assessed and were found to retain the adsorption capacity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1539–1546, 2006
Preparation and characterization of rare earth complex europium3+‐acrylate‐1,10‐phenanthroline grafted onto polypropylene
Authors: Pan Yuanfeng , Zheng Anna , Xiao Huining , Hu Fuzeng
Published: July 2006

Rare earth (RE) complex photoluminescence films were conventionally prepared by blending. The RE complexes were unevenly dispersed in the polymer matrix, thus readily quenching the fluorescence. An improved approach for preparing photoluminescence films was developed, in which the chemical or covalent bonding between the RE complex and polymer was introduced through melt‐grafting polymerization. An RE complex (europium3+‐acrylate‐1,10‐phenanthroline) [Eu(AA)3phen] was synthesized, and then grafted onto polypropylene (PP) in the melt phase to render the resin fluorescently active. The complex and the grafted PP were systematically characterized using various analytical tools including elemental analysis, TGA, IR DSC, WAXS, and fluorescence. The results indicated that the complex possessed favorable fluorescence and thermal stability, and the Eu(AA)3phen complex was successfully grafted onto the PP backbone. The findings from the DSC and WAXS measurements revealed that the complex acted as a nucleating agent, increasing the crystallization rate effectively and destroying the integrity of the crystallinity as well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1547–1552, 2006
Physical and electrochemical characterizations of poly(vinylidene fluoride‐co‐hexafluoropropylene)/SiO2‐based polymer electrolytes prepared by the phase‐inversion technique
Authors: Kim Kwang Man , Park Nam‐Gyu , Ryu Kwang Sun , Chang Soon Ho
Published: July 2006

Highly porous poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF–HFP)‐based polymer membranes filled with fumed silica (SiO2) were prepared by a phase‐inversion technique, and films were also cast by a conventional casting method for comparison. N‐Methyl‐2‐pyrrolidone as a solvent was used to dissolve the polymer and to make the slurry with SiO2. Phase inversion occurred just after the impregnation of the applied slurry on a glass plate into flowing water as a nonsolvent, and then a highly porous structure developed by mutual diffusion between the solvent and nonsolvent components. The PVdF–HFP/SiO2 cast films and phase‐inversion membranes were then characterized by an examination of the morphology, thermal and crystalline properties, absorption ability of an electrolyte solution, ionic conductivity, electrochemical stability, and interfacial resistance with a lithium electrode. LiPF6 (1M) dissolved in a liquid mixture of ethylene carbonate and dimethyl carbonate (1:1 w/w) was used as the electrolyte solution. Through these characterizations, the phase‐inversion polymer electrolytes were proved to be superior to the cast‐film electrolytes for application to rechargeable lithium batteries. In particular, phase‐inversion PVdF–HFP/SiO2 (30–40 wt %) electrolytes could be recommended to have optimum properties for the application. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 140–148, 2006
Synthesis of star‐shaped poly(ϵ‐caprolactone) by samarium‐based tetrafunctional initiator and its dilute‐solution properties
Authors: Xi Xiujuan , Jiang Liming , Ling Jun , Sun Weilin , Shen Zhiquan
Published: July 2006

An in situ–generated tetrafunctional samarium enolate from the reduction of 1,1,1,1‐tetra(2‐bromoisobutyryloxymethyl)methane with divalent samarium complexes [Sm(PPh2)2 and SmI2] in tetrahydrofuran has proven to initiate the ring‐opening polymerization of ϵ‐caprolactone (CL) giving star‐shaped aliphatic polyesters. The polymerization proceeded with quantitative conversions at room temperature in 2 h and exhibited good controllability of the molecular weight of polymer. The resulting four‐armed poly(ϵ‐caprolactone) (PCL) was fractionated, and the dilute‐solution properties of the fractions were studied in tetrahydrofuran and toluene at 30°C. The Mark–Houwink relations for these solvents were [η] = 2.73 × 10−2Mw0.74 and [η] = 1.97 × 10−2Mw0.75, respectively. In addition, the unperturbed dimensions of the star‐shaped PCL systems were also evaluated, and a significant solvent effect was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 175–182, 2006
Effect of vibration parameters of electromagnetic dynamic plastics injection molding machine on mechanical properties of polypropylene samples
Authors: Quan Wang , Qu Jin‐Ping , Liang He
Published: July 2006

Dynamic injection processing experiments have been carried out on polypropylene using the self‐made electromagnetic dynamic plastics injection molding machine, and the effects of the vibration force field on mechanical properties of molding samples are studied, namely, the influence of vibration frequency and vibration amplitude on the mechanical properties of samples are researched by using tensile testing, impact testing, differential scanning calorimeter (DSC) and scanning electronic micrograph (SEM) techniques. The results show that the tensile strength and impact strength are both enhanced and the melting point shifts toward the higher temperature, which facilitates the perfection of crystal. The best vibration parameters for processing polypropylene using electromagnetic dynamic plastics injection molding machine are that frequency is from 3 to 9 Hz and amplitude is from 0.1 to 0.4 mm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 972–976, 2006
Controlled release of bovine serum albumin using MPEG–PCL diblock copolymers as implantable protein carriers
Authors: Kim Moon Suk , Seo Kwang Su , Hyun Hoon , Khang Gilson , Cho Sun Hang , Lee Hai Bang
Published: July 2006

MPEG–PCL diblock copolymers consisting of methoxy polyethylene glycol (MPEG) and poly(ϵ‐caprolactone) (PCL) as drug carriers were synthesized by ring‐opening polymerization. It is possible to control the balance between hydrophilic and hydrophobic by changing the MPEG and the ratio of ϵ‐CL to MPEG. Implantable wafers were easily fabricated by the direct compression method after physical mixing of diblock copolymers and bovine serum albumin–fluorescein isothiocyanate (BSA‐FITC) as a model protein drug. The BSA release from wafers prepared by MPEG–PCL diblock copolymers were higher than that from PCL with the physical blending of MPEG. The wafers prepared by a variety of MPEG–PCL diblock copolymers exhibited the controlled BSA release profiles with a dependence on MPEG–PCL diblock copolymer compositions. In addition, the changing of MPEG and PCL molecular weights within MPEG–PCL diblock copolymer controlled the initial burst of BSA. We confirmed that the diblock copolymers could be served as protein delivery carrier in implantable wafer form. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1561–1567, 2006
Modification and characterization of poly(ethylene‐co‐vinyl alcohol) by glycosidation reaction
Authors: Liu Binyuan , Xue Zhixin , Liu Lu , Zhang Li , Liu Fang
Published: July 2006

Poly(ethylene‐co‐vinyl alcohol) was modified by the covalent bonding of a glucose ester via acetal formation of a surface hydroxyl group using acid as the catalyst. Grafted copolymers were characterized by 1H‐NMR, Fourier transform IR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:227–232, 2006
Influence of moisture regain of aramid fibers on effects of atmospheric pressure plasma treatment on improving adhesion with epoxy
Authors: Liu L. , Jiang Q. , Zhu T. , Guo X. , Sun Y. , Guan Y. , Qiu Y.
Published: July 2006

One difference between a low‐pressure plasma treatment and an atmospheric pressure plasma treatment is that in the atmosphere, the substrate material may contain significant quantities of moisture, which could potentially influence the effects of the plasma treatment. To investigate how the existence of moisture affects atmospheric pressure plasma treatment, aramid fibers (Twaron 1000) with three different moisture regains (0.5, 4.5, and 5.5%) were treated by an atmospheric pressure plasma jet for 3 s at a gas flow rate of 8 L/min, a treatment head temperature of 100°C, and a power of 10 W. The scanning electron microscopy analysis showed no observable surface morphology change for the plasma treated samples. X‐ray photoelectron spectroscopy analysis showed the oxygen contents of the 0.5 and 4.5% moisture regain groups increased from that of the control, although the opposite was true for the 5.5% moisture regain group. The advancing contact angles of the treated fibers decreased about 8°–16° whereas their receding contact angles decreased about 17°–27°. The interfacial shear strengths of the treated fibers as measured using microbond pull‐out tests were more than doubled when the moisture regain was 4.5 or 5.5%, whereas it increased by 58% when the moisture regain was 0.5%. In addition, no significant difference in single fiber tensile strength was observed among the plasma treated samples and the control sample. Therefore, we concluded that moisture regain promoted the plasma treatment effect in the improvement of the adhesion property of aramid fibers to epoxy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 242–247, 2006
Effect of carbon blacks on relaxation phenomenon of chlorobutyl vulcanizates
Authors: Sridhar V. , Choudhary R. N. P. , Tripathy D. K.
Published: July 2006

The effect of the types of carbon black on the physicomechanical, dynamic mechanical, and dielectric relaxation spectra in chlorobutyl vulcanizates was studied. The primary relaxation (α transition, the glass transition) was studied by dynamic mechanical analysis as a function of temperature (−60 to +100°C) and by positron annihilation lifetime spectroscopy (−70 to +100°C). Irrespective of the type of carbon black that was used, all composites showed glass‐transition temperatures in the range of −29 to −33°C, which was explained on the basis of the relaxation dynamics of polyisobutylene chains in the vicinity of the fillers. The secondary relaxation (α* or β relaxation) was studied using dielectric relaxation spectra in the frequency range of 100–106 Hz. The nonlinear strain dependent dynamical parameters (Payne effect) were also evaluated at dynamic strain amplitudes of 0.07–5%. The nonlinearity in the tan δ and storage modulus was explained by the concept of filler–polymer interactions and the interaggregate attraction (filler networking). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1809–1820, 2006
Effect of fatty amine and perfluorocarbon as anti‐fouling agent on the catalyst activity and titanium oxidation state in slurry polymerization of ethylene
Authors: Mousavi Mojtaba , Hakim Shokoofeh , Nekoomanesh Mehdi
Published: July 2006

In this work, the effect of two antifouling materials on the activity of catalyst used to produce polyethylene in a 1‐L slurry reactor and on the titanium oxidation state of the catalyst was investigated. Armostat 300 with the formula alkyl C14‐C18 bis(2‐hydroxyethyl)amine is an antistatic agent that reduces static electricity of the polymer particles. It was found that within the concentration of 0.16–1.32 g/mmol Ti, Armostat 300 helps to increase the catalyst activity to 1.3–2 times. The variation of the titanium oxidation state of the catalyst in the presence of Armostat 300 at 80°C with Al/Ti molar ratio of 100 showed that Ti (III) species increased. The effect of Armostat 300 on Tm, % Xc, density, bulk density, and MFI of polymer was insignificant. In this work, Zonyl FSN‐100 with the formula Rf(CH2CH2O)xH, Rf = F(CF2CF2)y, y = 1–9, x = 1–26 was used as antifouling agent in copolymerization of ethylene with 1‐butene. It was found that Zonyl FSN‐100 at the concentration range of 5–20 ppm reduces the catalyst activity to 1.11–1.9 times. It was also shown that Ti (III) species in the presence of Zonyl FSN 100 decreased. This antifouling agent slightly decreased the properties of polymer including % Xc, density, and Mw. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 257–260, 2006
Failure of multimaterial fusion bonding interface generated during over‐injection molding/thermoforming hybrid process
Authors: Aurrekoetxea J. , Castillo G. , Cortes F. , Sarrionandia M. A. , Urrutibeascoa I.
Published: July 2006

The effects of processing parameters on the strength of the fusion bonding interface have been investigated. The interface was generated when an isotactic polypropylene homopolymer was injection molded on a solid self‐reinforced polypropylene substrate. The interface strength was measured in shear configuration, and the melting behavior of substrate was studied using differential scanning calorimetry. The results show that strong bonding interface can be achieved when the correct processing parameters are chosen. The interfacial strength is largely improved if the interface temperature is higher than the melting temperature of the substrate layer, and in these specimens failure does not take place at the interface. Furthermore, for a fixed interface temperature, interface strength increases with thermal gradient. Finally, in the analyzed holding pressure range, pressure apparently has no effect on strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 261–265, 2006
Study on copolymerization of ethylene/1‐hexene catalyzed by a novel polystyrene‐supported metallocene catalyst
Authors: Wang Wenqin , Wang Li , Dong Xiaochen , Sun Tianxu , Wang Jianfeng
Published: July 2006

Ethylene/1‐hexene copolymerization was carried out with polystyrene‐supported metallocene catalyst. It was found that the kinetic of the copolymerization was strongly influenced by the steric hindrance of carrier. The influences of 1‐hexene concentration in the feed on catalyst productivity and comonomer reactivity were investigated. The microstructure of resultant copolymer was analyzed by 13C NMR. It was found that the different carriers have slight effect on the composite of copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1574–1577, 2006
Functionalization of chitosan membranes through phosphorylation: Atomic force microscopy, wettability, and cytotoxicity studies
Authors: Amaral I. F. , Granja P. L. , Melo Luís V. , Saramago B. , Barbosa M. A.
Published: July 2006

Grafting negatively charged groups such as phosphates is a well‐known strategy for inducing the deposition of apatite‐like layers under simulated physiological conditions. In this investigation, chitosan was phosphorylated in an attempt to enhance its osteoconduction. Chitosan membranes were phosphorylated at 30°C with the H3PO4/Et3PO4/P2O5/butanol reaction system for periods up to 48 h. This method is an alternative to the phosphoric acid/urea/dimethylformamide phosphorylation method, which involves the use of much higher temperatures. In this study, the effects of the phosphorylation reaction time on the surface morphology and surface free energy of phosphorylated membranes were investigated with atomic force microscopy and static‐contact‐angle measurements, respectively. In addition, the modified membranes were evaluated with respect to their cytotoxicity toward bone cells through the incubation of human osteoblastic cells with extracts of the materials for two different periods: 24 and 120 h. The results revealed a reduction of the average surface roughness at the nanometer scale with increasing phosphorylation reaction time. Wettability studies showed an increase in the polar component of the surface free energy with increasing reaction time as a result of the increase in the phosphate surface concentration. Cytotoxicity studies revealed no cytotoxic effect of phosphorylated membranes on osteoblastic cells, regardless of the incubation period. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 276–284, 2006
Fractionation of a silk fibroin hydrolysate and its protective function of hydrogen peroxide toxicity
Authors: Yeo Joo‐Hong , Lee Kwang‐Gill , Kweon Hae‐Yong , Woo Soon‐Ok , Han Sang‐Mi , Kim Sung‐Su , Demura Makoto
Published: July 2006

Fractionated components of Bombyx mori silk fibroin, which were hydrolyzed with protease, were prepared with a preparative‐recycling high‐performance‐liquid‐chromatography system to evaluate the protective effects of molecular‐weight‐controlled B. mori silk fibroin components on H2O2‐injured neuronal cells. Three major fractions, having molecular weights less than about 1500, were first collected with the recycling techniques. The highest protective effect of the molecular‐weight‐controlled B. mori silk fibroin components on H2O2‐injured neuronal cells was obtained when a fraction with a molecular weight of approximately 1400 was used. This protective effect of the silk fibroin hydrolysate on H2O2‐injured neuronal cells was suggested to correlate with the contents of aromatic amino acids such as tyrosine and phenylalanine.
© 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 772–776, 2006
Evaluation of anionic‐ and cationic‐supported hydrogel membranes for sorption of Th(IV) and U(VI) ions from nitric acid medium
Authors: Hegazy E. A. , El‐Gammal B. , Khalil F. H. , Mabrouk T. M.
Published: July 2006

Functionalized membranes were obtained by radiation‐induced graft copolymerization (RIGP) of acrylamide‐acrylic acid (AAm‐AAc) and acrylamide‐4‐vinyl pyridine (AAm‐4VP) binary monomers on both low‐density polyethylene and polypropylene films. The supporting conditions as inhibitor concentration, irradiation dose comonomer compositions and concentrations were studied and optimized. The prepared membranes were characterized using SEM, DTA‐TG, and FTIR. They proved that supporting the selected hydrogels on the base films have modified their structure and enhanced their thermal and mechanical characteristics. The sorption characteristics of Th(IV) and U(VI) on the different membranes were studied. The amount of ions sorbed at equilibrium was found to increase with increase in the degree of graft at certain conditions. The kinetics of sorption was also studied and found to obey the Lagergren and Morris–Weber kinetic models. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 320–332, 2006
Preparation of interpenetrating polymer network gel beads for dye absorption
Authors: Kusuktham Boonsri
Published: July 2006

Preparation of interpenetrating polymer network (IPN) gel beads for dye absorption was carried out by using simultaneous crosslinking method. First, sodium alginate (SA), 3‐(methacrylamido) propyl trimethyl ammonium chloride (MAPTAC), and/or acrylamide (AM), K2S2O8, and N,N′‐methylenebisacrylamide (MBAM) were mixed in aqueous solution. The beads were prepared using K2S2O8 and MBAM as the initiator and crosslinking agent, respectively. Then, the solution was dropped into CaCl2 solution mixed with N,N,N′,N′‐tetramethylethylenediamine (TMEDA). The former was used as the crosslinking agent of alginate and the latter was used as the accelerator for the polymerization of monomer in the alginate solution. The gel bead composed of only alginate was also prepared to compare the properties with IPN gel bead. The components in IPN gel bead were examined by FTIR analysis. The factors effecting the particle size of alginate and IPN gel beads were investigated. In alginate gel bead, the concentration of solution affected the particle size, whereas type of monomer affected the particle size of IPN gel bead. The IPN gel bead had smooth surface (from SEM results), different from the alginate bead. Alginate content caused the swelling behavior of dried IPN beads. Cationic dye was absorbed by crosslinked alginate gel bead. The absorption of reactive dye by IPN gel bead was a result of its cationic charge. The absorption density of IPN gel beads was the reciprocal of the absorbent dosage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1585–1591, 2006
The tensile properties of strain‐crystallizing vulcanizates. III. The superiority of conventional over peroxide vulcanizates in terms of network microstructure
Authors: Horst M. Van Der , McGill W. J. , Woolard C. D.
Published: July 2006

It is proposed that, when vulcanization is performed using peroxides, crosslinking leads to a simple network, whereas in conventional vulcanization crosslinking a partially interpenetrating polymer network (PIPN) is formed. Two unfilled polyisoprene networks of similar crosslink density, produced with dicumyl peroxide and 2‐bisbenzothiazole‐2,2′‐disulfide/sulfur formulations, were compared with respect to the effect of strain rate on their stress–strain and hysteresis curves at room and elevated temperatures. At high elongations, the stress–strain curves for peroxide vulcanizates show a steeper upturn than for conventional vulcanizates, but have lower tensile strength and elongation at break. On increasing the extension rate, stress–strain curves for peroxide vulcanizates rise less steeply, while conventional vulcanizates rise more steeply. For both vulcanizates the hysteresis ratio decreases on increasing the rate at which samples are extended and retracted. The effect on conventional vulcanizates is less than on peroxide vulcanizates. It is suggested that chains in peroxide networks disengage increasingly rapidly at higher strains, allowing increased strain‐induced crystallization. Rapid strain‐induced crystallization leads to low ultimate tensile strength (UTS). In more complex PIPNs, the disengagement and alignment of chains are retarded. The increased nonuniform extension of chains promotes early strain‐induced crystallization at low extensions, but overall it reduces the rate of crystallization, which occurs over a wider range of strains. This improves UTS and elongation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 876–884, 2006
Application of electrochemically produced and oxidized poly(3,4‐ethylenedioxythiophene) as anticorrosive additive for paints: Influence of the doping level
Authors: Liesa Francisco , Ocampo Cintia , Alemán Carlos , Armelin Elaine , Oliver Ramón , Estrany Francesc
Published: July 2006

This work investigates the resistance against marine corrosion of an epoxy‐based coating modified by the addition of electrochemically produced and oxidized poly(3,4‐ethylenedioxythiophene) (PEDOT). For this purpose, electrodeposition of PEDOT was performed on steel electrodes by electrochemical polymerization of 3,4‐ethylenedioxythiophene. The doping level of the resulting material was increased by chronoamperometry and chronopotentiometry (CP), three different oxidation degrees being achieved. The electrochemical and electrical properties of such three samples, which were used as anticorrosive additives, were examined. Furthermore, the physical properties of the coating before and after addition of the conducting polymers were characterized using FTIR, thermal analyses, and mechanical properties evaluations. Accelerated corrosion tests indicated that the polymer with the highest amount of positive charge per monomeric unit, which was achieved by CP, enhances considerably the anticorrosive protection imparted by the coating. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1592–1599, 2006
Preparation and properties of microporous cellulose membranes from novel cellulose/aqueous sodium hydroxide solutions
Authors: Cao Yu , Tan Huimin
Published: July 2006

Microporous cellulose membranes were prepared from novel cellulose/aqueous sodium hydroxide solutions by coagulation with aqueous H2SO4 solutions. The free and glass‐contacting surface morphology of the microporous cellulose membranes showed an asymmetric porous structure. The morphological structure, tensile properties, and permeability of the microporous cellulose membranes could be controlled by changes in the coagulation conditions such as the coagulant concentration and the coagulation time.
© 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 920–926, 2006
Structure and properties of nanocomposites based on poly(butylene succinate) and organically modified montmorillonite
Authors: Ray Suprakas Sinha , Okamoto Kazuaki , Okamoto Masami
Published: July 2006

Poly(butylene succinate) and organically modified montmorillonite nanocomposites with there different compositions were prepared via melt blending in a twin‐screw extruder. The structure of the nanocomposites was studied with X‐ray diffraction and transmission electron microscopy, which revealed the formation of intercalated nanocomposites, regardless of the silicate loading. Dynamic mechanical analysis revealed a substantial increase in the storage modulus of the nanocomposites over the entire temperature range investigated. The tensile property measurements showed a relative increase in the stiffness with a simultaneous decrease in the yield strength in comparison with that of neat poly(butylene succinate). The oxygen gas barrier property of neat poly(butylene succinate) improved after nanocomposite preparation with organically modified montmorillonite. The effect of the layered‐silicate loading on the melt‐state linear viscoelastic behavior of the intercalated nanocomposites was also investigated.
© 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 777–785, 2006
Synthesis and characterization of modified bismaleimide/polysulfone semi‐interpenetrating polymer networks
Authors: Kurdi Jamal , Kumar Ashwani
Published: July 2006

The present work reports a new method of preparing semi‐interpenetrating polymer network (semi‐IPN) membranes through in situ polymerization of bismaleimide (BMI) within polysulfone (PSF). It was found that BMI could be polymerized at ambient conditions in the presence of a proton donor and PSF without the use of an initiator or a catalyst. Chemical structure characterization of these semi‐IPNs by Fourier transform infrared attenuated total reflection (FTIR‐ATR) revealed the possibility of imide cleavage and formation of amic acid when BMI polymerization was continued for a longer time while X‐ray photoelectron spectroscopy (XPS) revealed the protonation of imide nitrogen at shorter polymerization time. It was also found that size of thermoset BMI phase within the PSF thermoplastic has a significant impact on glass‐transition temperature of resulting semi‐IPN. By controlling the thermoset/thermoplastic phase separation of semi‐IPNs through dope composition and formation techniques, gas separation membranes with comparable selectivity and permeance that were up to 12 times higher than corresponding PSF membranes were formed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 369–379, 2006
Preparation and characterization of high refractive index thin films of TiO2/epoxy resin nanocomposites
Authors: Guan Cheng , Lü Chang‐Li , Liu Yi‐Fei , Yang Bai
Published: July 2006

By using sol–gel method, amorphous titania was introduced into epoxy matrix to prepare a series of high refractive index TiO2/epoxy resin nanocomposite films. To increase the refractive index of the hybrid films, triethoxysilane‐capped trimercaptothioethylamine (TCTMTEA), a new kind of high refractive index coupling agent was synthesized from trimercaptothioethylamine (TMTEA). In the experiment, TCTMTEA acted as the solidification agent together with TMTEA except being used as the coupling agent. The hybrid films have been characterized via FTIR, AFM, DSC, TGA, etc. The experimental results showed that the amorphous TiO2 had been dispersed uniformly in the organic polymer matrix with the size smaller than 100 nm in each sample. More importantly, the refractive index of this kind of materials can be continuously adjusted from 1.61 to 1.797 with the content of TiO2 increasing from 0% to 65% in mass, and the continuously adjusted refractive index is very important for the applications in optical antirefractive films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1631–1636, 2006
Investigation on gradient dielectric characteristics of bamboo (Dentroclamus strictus)
Authors: Chand Navin , Jain Deepak , Nigrawal Archna
Published: July 2006

Dependence of dielectric constant (ε′) and dielectric dissipation factor (tan δ) on distance from outermost skin to the center of bamboo has been determined. Dielectric measurements have been done in the temperature range of 24–120°C and in the frequency range, 4–100 kHz. Gradient behavior in ε′ and tan δ has been found in bamboo. It has also been observed that ε′ and tan δ increase with increasing temperature and decrease with increasing frequency. Relaxation times have been calculated for the four samples at 80, 90, and 100°C temperatures, which show that relaxation time decreases with the increase of temperature because of the increased molecular mobility. A continuous increase in the hardness from center (48) to outer surface (70) and density from 0.45 to 0.80 g/cc has been observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 380–386, 2006