bluuebunny/crossref_metadata_2025 huggingface dataset:
Percutaneous Endoscopic Interlaminar Discectomy for Intracanalicular Disc Herniations At L5–S1 Using a Rigid Working Channel Endoscope
Authors: Choi Gun , Lee Sang-Ho , Raiturker Pradyumna Pai , Lee Seungcheol , Chae Yu-Sik
Published: February 2006

OBJECTIVE:

Percutaneous endoscopic transforaminal discectomy is often used as a minimally invasive procedure for lumbar disc herniation. However, a transforaminal approach posts limitations at the L5–S1 level owing to anatomic constraints, such as a high iliac crest or small intervertebral foramen and especially for migrated large intracanalicular disc herniations. We discuss the procedure and clinical results of percutaneous endoscopic interlaminar discectomy using a rigid working channel endoscope at the L5–S1 level and the relevant surgical anatomy.

METHODS:

We performed percutaneous endoscopic discectomy through the interlaminar approach in 67 patients who satisfied our inclusion criteria during the period from March 2002 to November 2002. All procedures were performed under local anesthesia. Under fluoroscopic guidance, we performed discography using indigocarmine mixed with radio-opaque dye. The 6-mm working channel endoscope was then introduced into the epidural space. Herniated disc material was removed using forceps and laser under clear endoscopic visualization. We retrospectively evaluated the 65 cases with more than 1.5 years of follow-up. The patients were evaluated using the visual analogue scale (VAS) and the Oswestry Disability Index (ODI).

RESULTS:

VAS for leg pain (preoperative mean, 7.89; postoperative mean, 1.58) and ODI (preoperative mean, 57.43; postoperative mean, 11.52) showed statistically significant (P = 0.00) improvement in their values at the last follow-up examination compared with preoperative scores. Of the study group, 90.8% individuals showed favorable result. The mean hospital stay was 12 hours. The average time to return to work was 6.79 weeks. Complications included two cases of dural injury with cerebrospinal fluid leakage, nine cases of dysesthesia that were transient, and one case of recurrence. Two patients required conversion to open procedure at the initial operation. There was no evidence of infection in any patients.

CONCLUSION:

Percutaneous endoscopic interlaminar discectomy is a safe, effective, and minimally invasive procedure for the treatment of intracanalicular disc herniations at the L5–S1 level in properly selected cases, especially when the transforaminal approach is not possible because of anatomic constraints.
Scalp to Meningeal Arterial Anastomosis in the Parietal Foramen
Authors: Yoshioka Nobutaka , Rhoton Albert L. , Abe Hiroshi
Published: February 2006

OBJECTIVE:

The purpose of this study was to examine the parietal foramen and to determine whether it is the site of an anastomosis between the meningeal and scalp arteries.

METHODS:

Forty parietal regions from 20 adult cadavers, in which the arteries were perfused with colored latex, were examined for this study. The scalp was separated from the parietal foramen, and the vasculature in the foramen and adjacent scalp and dura were examined using ×3 magnification. The scalp arteries that anastomosed with the meningeal arteries through the parietal foramen were followed into the dura after craniotomy.

RESULTS:

Parietal foramen was found in 20 of the 40 (50%) parietal regions. They were present bilaterally in eight heads and unilaterally in four. Every parietal foramen transmitted an anastomosis between the middle meningeal and scalp arteries. In 11 (55%) of the 20 foramina found in this study, the superficial temporal and occipital artery formed an anastomosis in the galea and pericranial layer that sent a branch through the parietal foramen to anastomose with parietal branches of the middle meningeal artery. In the remaining nine (45%) sides, the middle meningeal artery had a connection through the foramen with a small pericranial artery.

CONCLUSION:

Every parietal foramen was the site of a connection between the middle meningeal and scalp arteries. The scalp end of the anastomosis most commonly arose in an anastomosis between the superficial temporal and occipital arteries. This anastomosis may be involved in several pathologies.
Comparative Analysis of Anterior Petrosectomy and Transcavernous Approaches to Retrosellar and Upper Clival Basilar Artery Aneurysms
Authors: Figueiredo Eberval Gadelha , Zabramski Joseph M. , Deshmukh Puspha , Crawford Neil R. , Spetzler Robert F. , Preul Mark C.
Published: February 2006

OBJECTIVE:

To compare two techniques, transcavernous approach (TcA) and anterior petrosectomy (AP), used to manage retrosellar and upper clival basilar artery (BA) aneurysms.

METHODS:

AP and TcA were carried out on nine sides of cadaver heads. With use of a computerized tracking system, the area of surgical exposure in the ventral surface of the brain stem, the superficial area of exposure, and the linear exposure of the BA were evaluated. The angles of approach in the horizontal and vertical axes were measured using a robotic microscope. The caudal extent of exposure was determined by an aneurysm clip applied to proximal BA, and the distance between the clip and the floor of the sella was quantified after performing TcA.

RESULTS:

TcA (1127.3 ± 438.4 mm2) provided a greater superficial exposure than AP (697.7 ± 219.1 mm2) (P = 0.01). There were no statistical differences in the deep working exposure (P = 0.303) between TcA (206.9 ± 40.7 mm2) and AP (260.2 ± 137.1 mm2). The linear exposure of the BA was greater for AP (22.7 ± 6.2 mm2) than for the TcA (12.8 ± 2.9 mm2) (P = 0.004). The caudal extent of exposure averaged 6.1 mm from the floor of the sella. No differences were found in horizontal angles (P = 0.596); however, vertical angles were significantly greater for the TcA than AP (15.2 ± 3.4) (P = 0.004).

CONCLUSION:

From an anatomic standpoint, the TcA offers more advantages than the AP, when approaching retrosellar BA aneurysms, except for those cases in which proximal control is the principal issue and the neck of the aneurysm is located more than 6.0 mm below the floor of the sella.
Endoscopic Transsphenoidal Pituitary Surgery with Intraoperative Magnetic Resonance Imaging
Authors: Schwartz Theodore H. , Stieg Phillip E. , Anand Vijay K.
Published: February 2006

OBJECTIVE:

The two most recent significant advances in pituitary surgery have been the endonasal endoscopic approach and intraoperative magnetic resonance imaging (IMRI). Each provides improved visualization of intra- and parasellar anatomy with the goal of attaining a complete resection. The combination of the two techniques has not been previously reported in the literature.

METHODS:

We performed endoscopic, endonasal resection of pituitary macroadenomas in 15 patients using the Polestar N-10 (0.12T) IMRI (Odin Medical Technologies, Inc., Newton, MA). Eleven patients had nonfunctioning tumors, three had acromegaly, and one had a medication-resistant prolactinoma. The effect of the magnetic field on the cathode ray tube screen and the image quality of the IMRI images were assessed. The presence of residual tumor on IMRI was noted and then re-examined with the endoscope.

RESULTS:

Although the Polestar N-10 is a low Tesla magnet, the IMRI caused significant distortion of the cathode ray tube screen regardless of the viewing angle. This was overcome with the use of a wall-mounted plasma screen. IMRI images were obtained in all cases and were of sufficiently high quality to demonstrate adequate decompression of the optic chiasm and the removal of all suprasellar tumor. In three cases, residual tumor was found with IMRI that was resected endoscopically before the completion of surgery. In four other cases, potential residual tumor was examined endoscopically and found to be normal postoperative change. In eight cases no residual intrasellar tumor was seen on the IMRI. Preresection visual deficits improved in all cases and the insulin-like growth factor levels normalized in two of three cases. There were no delayed cerebrospinal fluid leaks.

CONCLUSION:

Combining intraoperative endoscopy and IMRI is feasible and distortion of the cathode ray tube screen can be overcome with the use of either a plasma or liquid crystal display screen. Each technology provides complementary information, which can assist the surgeon in safely maximizing the extent of resection. In this small series using a low-field magnet, rates of residual tumor following endoscopic trans-sphenoidal surgery were less than have been reported following microscope-based transsphenoidal surgery.
Characteristics of the glmS ribozyme suggest only structural roles for divalent metal ions
Authors: ROTH ADAM , NAHVI ALI , LEE MARK , JONA INBAL , BREAKER RONALD R.
Published: February 2006

The glmS ribozyme is a riboswitch class that occurs in certain Gram-positive bacteria, where it resides within mRNAs encoding glucosamine 6-phosphate synthase. Members of this self-cleaving ribozyme class rapidly catalyze RNA transesterification upon binding GlcN6P, and genetic evidence suggests that this cleavage event is important for down-regulating GlmS protein expression. In this report, we present a refined secondary structure model of the glmS ribozyme and determine the importance of a conserved pseudoknot structure for optimal ribozyme function. Analyses of deletion constructs demonstrate that the pseudoknot, together with other structural elements, permits the ribozyme to achieve maximum rate constants for RNA cleavage at physiologically relevant Mg2+ concentrations. In addition, we show that substantial rate enhancements are supported by an exchange-inert cobalt (III) complex and by molar concentrations of monovalent ions. Our findings indicate that the glmS ribozyme forms a complex structure to employ catalytic strategies that do not require the direct participation of divalent metal ions.
The crystal and molecular structures of sodium and barium complexes of dibenzo-24-crown-8 ether
Authors: Schilde Uwe , Erk Çakil , Kleinpeter Erich
Published: February 2006

The sodium and barium isothiocyanate complexes of 6,7,9,10,12,13,20,21,23,24,26,27-dodecahydro-dibenzo[b,n]-1,4,7,10,13,16,19,22-octaoxacyclotetracosin (dibenzo-24-crown-8 ether=DB24C8) were synthesized and analyzed by X-ray diffraction.

The sodium complex, [Na(DB24C8)(NCS)(H2O)] 1, crystallizes in the orthorhombic space group Fdd2 with 16 molecules in the unit cell. The coordination number of Na is 6 and the central ion is located in a distorted octahedric environment. Only four of the crown ether oxygen atoms are involved. The coordination polyhedron is completed by the isothiocanate anion and by a water molecule, which is stabilized by hydrogen bonds.

The barium complex, [Ba(DB24C8)(NCS)2] 2, crystallizes in the trigonale space group P3121 with 3 molecules in the unit cell. Crystallographic C2 symmetry is observed for the complex. The coordination number of Ba is 10. Barium is coordinated with the eight oxygen atoms of the macrocyclic ligand and with two isothiocyanate anions. The absolute structure was estimated using the FLACK parameter.
Involvement of Niemann-Pick Type C2 Protein in Hematopoiesis Regulation
Authors: Heo Kyu , Jariwala Unnati , Woo Jeongim , Zhan Yuxia , Burke Kathleen A. , Zhu Lunjian , Anderson W. French , Zhao Yi
Published: February 2006

Niemann-Pick type C2 (NPC2) protein has been characterized as a cholesterol-binding protein. Its loss leads to NPC2 disease, an inherited neurodegenerative disorder. When analyzing gene expression profile, we noticed high expression of both NPC2 and its receptor, mannose 6-phosphate receptor (MPR), in murine hematopoietic stem cells. NPC2 protein, in the presence of thrombopoietin (TPO), causes an increase in CFU-GEMM (colony-forming unit-granulocyte-erythroid-macrophage-megakaryocyte) and a decrease in CFU-GM (colony-forming unit-granulocyte-macrophage) colony number in colony-forming cell (CFC) assays. This effect is independent of cholesterol binding but does require the presence of MPR. With M07e cells, a TPO-dependent hematopoietic leukemia cell line, NPC2 can inhibit TPO-induced differentiation and enhance TPO-mediated anti-apoptosis effects. Strikingly, these results are not observed under the standard 20% O2 level of the standard incubator, but rather at 7% O2, the physiological oxygen level of bone marrow. Furthermore, NPC2 protein upregulates hypoxia inducible factor 1-α protein level at 7% O2, but not at 20% O2. Our results demonstrate that NPC2 protein plays a role in hematopoiesis at the physiologic bone marrow level of O2.
Regulatory Agencies
Authors: Passow Nancy R. , Yingling Gary L. , Onel Suzan
Published: February 2006

Because of updates and reauthorization, regulations covering health, safety, and environmental issues change continuously and specifications can become outdated. Regulatory agencies provide assistance regarding the laws and regulations of these issues. The two main federal agencies involved in the protection of human health and the environment are the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA). Primary laws covered by the EPA are the Clean Air Act Amendments (CAAA); the Clean Water Act (CWA); Resource Conservation and Recovery Act (RCRA); Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA); Toxic Substances Control Act (TSCA); and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The principal function of OSHA is the protection of people in the workplace. Other functions of regulatory agencies, eg, agriculture, commerce, defense, and energy, are discussed.

The Food and Drug Administration (FDA) is the primary federal scientific and regulatory government agency that monitors drug, biologic, medical device, food, veterinary and cosmetic products. FDA is organized into five distinct centers, each with its own rules and regulations. This article discusses FDA’s traditional regulatory mission of consumer protection and how its decisional processes have changed over time as a result of the explosion of advances within analytical chemistry and toxicology. Because no compound is completely safe, FDA must regularly assess the intended use of a product and whether the level of risk is acceptable. The article also summarizes the legislation that sets the boundaries of FDA’s authority and lays out the administration’s organization and responsibilities.

The chemical process industry is highly regulated in the environmental, health, and safety area. Everything is affected, from the siting of a new facility to the transportation of raw materials and finished products, from the working conditions for employees to operating requirements for processes, packaging of finished goods, and dealings with the community. The two main U.S. Federal agencies involved in the protection of human health and the environment are the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA). The EPAs principal concern is the protection of the environment; in most cases, the area outside of an industrial facility. Significant laws covered by EPA are discussed.
Posterior hypothalamic activation in paroxysmal hemicrania
Authors: Matharu Manjit S. , Cohen Anna S. , Frackowiak Richard S. J. , Goadsby Peter J.
Published: February 2006

Objective

Paroxysmal hemicrania (PH) is a severe, strictly unilateral headache that lasts 2 to 30 minutes, occurs more than five times daily, is associated with trigeminal autonomic symptoms, and is exquisitely responsive to indomethacin. The purpose of the study was to determine the brain structures active in PH.

Methods

Seven PH patients were studied using positron emission tomography (PET). Each patient was scanned in three states: (1) acute PH attack–off indomethacin; (2) pain‐free–off indomethacin; and (3) pain‐free after administration of intramuscular indomethacin 100mg. The scan images were processed and analyzed using SPM99.

Results

The study showed no significant activations during state 1 compared with state 2, but there was relative activation of the pain neuromatrix in both states 1 and 2 compared with state 3. This suggests that there is persistent activation of the pain neuromatrix during acute PH attacks and during interictal pain‐free states off indomethacin that is deactivated by the administration of indomethacin. In addition, the untreated PH state was associated with significant activation of the contralateral posterior hypothalamus and contralateral ventral midbrain, which extended over the red nucleus and the substantia nigra.

Interpretation

These activated subcortical structures may play a pivotal role in the pathophysiology of this syndrome. Ann Neurol 2006;59:535–545
Synthesis and characterization of poly(thiophen‐3‐yl acetic acid 4‐pyrrol‐1‐yl phenyl ester‐co‐N‐methylpyrrole) and its application in an electrochromic device
Authors: Bingöl Bahar , Camurlu Pinar , Toppare Levent
Published: February 2006

Copolymer of thiophen‐3‐yl acetic acid 4‐pyrrol‐1‐yl phenyl ester (TAPE) with N‐methylpyrrole (NMPy) was synthesized by potentiostatic electrochemical polymerization in acetonitrile–tetrabutylammonium tetrafluoroborate solvent–electrolyte couple. The chemical structures were confirmed via Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and UV–vis spectroscopy. Electrochromic and spectroelectrochemical properties of poly(TAPE‐co‐NMPy) [P(TAPE‐co‐NMPy)] were investigated. Results showed that the copolymer revealed color change between light yellow and green upon doping and dedoping of the copolymer, with a moderate switching time. Furthermore, as an application, dual‐type absorptive/transmissive polymer electrochromic device (ECD) based on poly(TAPE‐co‐NMPy) and poly(3,4‐ethylene dioxythiophene) (PEDOT) have been assembled, where spectroelectrochemistry, switching ability, stability, and optical memory of the ECD were investigated. Results showed that the device exhibited good optical memory and stability with moderate switching time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1988–1994, 2006
Three‐dimensional solubility parameters of poly(ε‐caprolactone)
Authors: Huang Jan‐Chan , Lin Ko‐Ting , Deanin Rudolph D.
Published: February 2006

The three‐dimensional solubility parameter model was applied to analyze solution thermodynamic data of 27 solutes in poly(ε‐caprolactone) (PCL) between 70 and 110 °C. A linear regression method was compared with a nonlinear least square regression method, which searches solubility parameter components by minimization of the sum of error squares. The parameters of polymers were the same by both methods. When compared with the error in predicting χRT/V, the data showed a different slope from the simple three‐dimensional model. These deviations were reduced by a different model using a smaller weight on the polar and hydrogen bonding components. In the new model, the solubility parameter components were closer to the value of a structure analogue of PCL. The confidence intervals for the parameters were estimated from a linearized equation based on the sum of error squares. The solubility parameter components obtained were different from the average values of the five solutes with the smallest χ. The inclusion of solutes with high hydrogen bonding components contributed to the increase of the component in the nonlinear regression method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2002–2009, 2006
Microwave‐irradiated ring‐opening polymerization of D,L‐lactide under atmosphere
Authors: Jing Shu , Peng Wang , Tong Zheng , Baoxiu Zhao
Published: February 2006

Poly(D,L‐lactide) (PDLLA) was synthesized by microwave‐irradiated ring‐opening polymerization catalyzed by stannous octoate (Sn(Oct)2) under atmosphere. The effects of heating medium, monomer purity, catalyst concentration, microwave irradiation time, and vacuum level were discussed. Under the appropriate conditions such as carborundum (SiC) as heating‐medium, 0.15% catalyst, lactide with purity above 99.9%, 450 W microwave power, 30 min irradiation time, and atmosphere, PDLLA with a viscosity–average molecular weight (Mη) over 2.0 × 105 and a yield over 85% was obtained. The dismission of vacuum to ring‐opening polymerization of D,L‐lactide (DLLA) under microwave irradiation simplified the process greatly. The temperature under microwave irradiation and conventional heating was compared. The largely enhanced ring‐opening polymerization rate of DLLA under microwave irradiation was the coeffect of thermal effects and microwave effects. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2244–2247, 2006
Separation characteristics of acetic acid–water mixtures by using poly(vinyl alcohol‐g‐4‐vinyl pyridine) membranes by pervaporation and temperature difference evapomeation techniques
Authors: Asman Gülsen , şanlı Oya
Published: February 2006

The separation of acetic acid–water mixtures was carried by using pervaporation (PV) and temperature difference evapomeation (TDEV) methods. For the separation process 4‐vinyl pyridine was grafted on poly(vinyl alcohol). Membranes were prepared from the graft‐copolymer by casting method and crosslinked by heat treatment. The effect of feed composition on the separation characteristics was studied and the performances of the separation methods were compared. Permeation rates obtained in PV were found to be high, whereas separation factors were high in TDEV method. Membranes gave permeation rates of 0.1–3.0 kg/(m2 h) and separation factors of 2.0–61.0, depending on the composition of the feed mixture and the method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2030–2039, 2006
Synthesis and characterization of negative‐type polyamic acid ester with 1‐methacryloyloxy‐2‐propanoate group
Authors: Choi Sung Mook , Kwon Soo‐Han , Yi Mi Hye
Published: February 2006

A negative‐type photosensitive polyamic acid (PAA) was synthesized from cyclobutane‐1,2,3,4‐tetracarboxylic dianhydride and 2‐(methacryloyloxy)ethyl 3,5‐diaminobenzoate in N‐methyl‐2‐pyrrolidinone. Glycidyl methacrylate was added into the PAA solution to yield a photosensitive PAA ester (PAE) by the ring‐opening esterification reaction of the carboxylic acid group in the PAA and glycidyl methacrylate. Esterification reactions were conducted with varying reaction temperatures and times. The typical PAE (PAE‐C3) with a degree of esterification of 20% was used for a photosensitivity study. We investigated the effects of the postexposure baking temperature, amount of photoinitiator, and exposure dose on the photosensitivity of PAE‐C3. Furthermore, a photolithography evaluation was conducted on PAE‐C3 in the presence of 1‐[4‐(phenylthio)phenyl]‐2‐(O‐benzoyloxime)‐1,2‐octanedione as a photoinitiator using a mercury lamp at a 365‐nm wavelength. The resolution of the film with 2.0‐μm thickness was about 8 μm. PAE‐C3 cured at 250°C for 60 min was stable up to around 310°C in a nitrogen atmosphere. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2252–2258, 2006
Loading rate effects on mechanical properties of polymer composites at ultralow temperatures
Authors: Ray Bankim Ch.
Published: February 2006

E‐glass fibers of 55, 60, and 65 weight percentages were reinforced with epoxy matrix to prepare the laminated composites. They were exposed to −40, −60, and −80°C temperatures for different times. The 3‐piont bend test was conducted on the conditioned samples at those temperatures. Mechanical test was carried out at 2 mm/min and 500 mm/min crosshead speeds. The main emphasis of the investigation was to evaluate the roles of percentage matrix phase and interfacial areas on the interlaminar shear failure mechanism of glass/epoxy composites at ultralow temperatures for different loading speeds. The mechanical performances of the laminated specimens at low temperatures were compared with room temperature property. The loading rate sensitivity of the polymer composites appeared to be inconsistent and contradictory at some points of conditioning time and as well as at a temperature of conditioning. This Phenomenon may be attributed to low‐temperature hardening, matrix cracking, misfit strain due to differential thermal coefficient of the constituent phases, and also to enhanced mechanical keying factor by compressive residual stresses at low temperatures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2289–2292, 2006
The effect of different metallic catalysts on the coreaction of cyanate/epoxy
Authors: Li Qi Fang , Lu Kun , Yang Qingquan , Jin Riguang
Published: February 2006

The curing reaction between the diepoxy and dicyanate mixed resins in the presence of three different catalysts Cu(AcAc)2, manganese octoate, and copper octoate was investigated. The thermal behavior was monitored using differential scanning calorimeter; the transformations of structures during the isothermal and heating process were explored by Fourier transform infrared spectroscopy; the changes of the carbonic‐framework of polymer and intermediate products were analyzed by nuclear magnetic resonance. Conclusions can be drawn as follows: Similar to noncatalyzed system, the overall reaction still occurs in two steps: cyclotrimerization of cyanate ester to produce triazine rings, coupled with the formation of some secondary intermediate products, and coreaction of epoxy and triazine rings to form oxazolidinone rings at high temperature. The catalysts can accelerate the curing process and decrease the curing temperature as well as gel time, and manganese octoate presents the best effect on curing rate. But the mechanisms and the structures of intermediate products of metallic‐catalyzed epoxy/cyanate are not changed by the addition of catalysts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2293–2302, 2006
Effect of thermal shock on interlaminar strength of thermally aged glass fiber‐reinforced epoxy composites
Authors: Ray Bankim Chandra
Published: February 2006

Glass fiber/epoxy composites were thermally conditioned at 50, 100, 150, 200, and 250°C for different periods of time and then immediately quenched directly in ice‐cold water from each stage of conditioning temperature. The polymerization or depolymerization by thermal conditioning and the debonding effect by concurrently following thermal shock in polymer composites are assessed in the present study. The short‐beam shear tests were performed at room temperature on the quenched samples to evaluate the value of interlaminar shear strength of the composites. The short conditioning time followed by thermal shock resulted in reduction of shear strength of the composites. The strength started regaining its original value with longer conditioning time. Conditioning at 250°C and thereafter quenching yielded a sharp and continuous fall in the shear strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2062–2066, 2006
Preparation and properties of biodegradable thermoplastic starch/poly(hydroxy butyrate) blends
Authors: Lai S.‐M. , Don T.‐M. , Huang Y.‐C.
Published: February 2006

The vital differences using three types of thermoplastic starches (TPS), including potato starch, corn starch, and soluble potato starch, with two different gelatinization degrees to blend with poly(hydroxy butyrate) (PHB) are thoroughly discussed in this study. For blends containing a certain amount of PHB, thermal stability remains in a certain degree. In all cases of this study, mechanical properties of TPS blended with PHB confer higher performance than those of pristine TPS. In particular, a significant increase on tensile strength and tear strength is observed for TPS (potato starch) blended with PHB at low gelatinization degree. A suitable degree of gelatinization of starch is critical to achieve optimum performance. The investigation on the morphological observation partly features the supporting evidence of the above findings. The assessment of biodegradability indicates that the values of water absorption and weight loss increase with increasing treatment period and glycerol content, but decrease with increasing amount of PHB content. Among three types of starches investigated, the TPS (soluble starch)/PHB blend gives the highest level of water absorption and weight loss. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2371–2379, 2006
Thermal and surface characterization of polyurethane–urea clay nanocomposite coatings
Authors: Sreedhar B. , Chattopadhyay D. K. , Swapna V.
Published: February 2006

This paper reports synthesis and characterization of polyurethane–urea (PU‐urea) and the nanocomposites derived from the PU‐urea with silicate clays. Organophilic montmorillonite cotreated by cetyl trimethyl ammonium bromide (CTAB) was synthesized and used to prepare PU‐urea/montmorillonite nanocomposites coatings. PU‐ureas were prepared from polyethylene glycol (PEG), polypropylene glycol (PPG), trimethylol propane (TMP), and 4,4′‐diphenylmethane diisocyanate (MDI) by reacting excess diisocyanate with polyether glycols. The excess isocyanate of the prepolymers was cured with atmospheric moisture. The synthesized moisture cured PU‐urea and nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetric (DSC), and angle resolved X‐ray photoelectron spectroscopy (AR‐XPS). The thermal stability of the PU‐urea nanocomposites was higher relative to the mother PU‐urea films. DSC results showed a slight enhancement in the soft segment glass transition temperature after 3 wt % clay loading. The surface properties showed an enrichment of the soft segment toward the surface. An enhancement in the hard segment composition in the nanocomposite coatings has resulted in enhancing the phase mixing process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2393–2401, 2006
Preparation and characterization of nanocomposite hydrogels based on polyacrylamide for enhanced oil recovery applications
Authors: Zolfaghari Reihaneh , Katbab Ali A. , Nabavizadeh Javad , Tabasi Ramin Yousefzadeh , Nejad Majid Hossein
Published: February 2006

In the present work, attempts have been made to prepare nanocomposite type of hydrogels (NC gels) by crosslinking the polyacrylamide/montmorillonite (Na‐MMT) clay aqueous solutions with chromium (III). The X‐ray diffraction patterns of the NC gels exhibited a significant increase in d001 spacing between the clay layers, indicating the formation of intercalated as well as exfoliated type of morphology. Exfoliation of the clay layers through out the gel network was found to be predominated, which evidences the high interaction between the polyacrylamide segments and montmorillonite layers. Gelation time as well as variation of viscoelastic parameters such as storage modulus (G′) of the gel network during gelation process at 75°C was studied and followed by rheomechanical spectroscopy (RMS). The NC gels prepared with lower crosslinker concentration showed higher strength and elastic modulus compared with the similar but unfilled polyacrylamide gel. This distinct characteristic of the NC gels yields a gel network structure with high resistance towards syneresis at high temperature in the presence of the oil reservoir formation water. The effects of the composition, such as clay content, crosslinker concentration, and also water salinity upon the gelation rate, gel strength as well as rate of syneresis have been investigated. To optimize the injectivity of the intercalated polyacrylamide solution before the onset of gelation with the gel strength of the final developed gel, sodium lactate was employed as retarder. This was found to be effective to balance these two characteristics of the NC gels, which are aimed to be used for water shut‐off and as profile modifier in enhanced oil recovery (EOR) process during water flooding process. The nanocomposite gels showed much more elasticity and extensibility at low crosslinker concentration compared with the similar but unfilled gel, which makes the NC gels suitable as an in‐depth profile modifier, and also as an oil displacing agent in the heterogeneous oil reservoir in chemical EOR. Effects of the clay content on the thermal stability of the gel network have also been investigated by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) has been performed upon the NC‐gel samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2096–2103, 2006
Supramolecular magnetorheological polymer gels
Authors: Hu B. , Fuchs A. , Huseyin S. , Gordaninejad F. , Evrensel C.
Published: February 2006

Novel magnetorheological fluids—supramolecular magnetorheological polymer gels (SMRPGs)— were investigated. Supramolecular polymer deposited on the surface of iron particles was suspended in the carrier fluids. The supramolecular network was obtained by metal coordination between terpyridine monomers and zinc ion. These SMRPGs had such advantages as controllable off‐state viscosity, a reduced iron particle settling rate, and stability. The viscoelastic behavior of SMRPGs with small‐ and large‐amplitude oscillatory shear was investigated using the amplitude and frequency sweep mode. The effects of strain amplitude, frequency, and magnetic field strength on the viscoelastic moduli were measured. The linear viscoelastic (LVE) strain range was obtained by the oscillation and static stress strain methods. The maximum LVE value was equal to the preyield strain point, 0.3%. Microstructural variation of SMRPG is proposed as an explanation of the rheological changes in the oscillation tests. The results of this research indicate that off–state viscosity and particle settling can be controlled by adjusting the concentration of supramolecular polymer gel. Dynamic yield stress significantly increased with an external magnetic field up to ∼23,500 Pa under a magnetic flux density of 500 mT. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2464–2479, 2006
Composite anion exchange membrane for alkaline direct methanol fuel cell: Structural and electrochemical characterization
Authors: Huang Aibin , Xia Chaoyang , Xiao Chaobo , Lin Zhuang
Published: February 2006

A copolymer of 4‐vinylpyridine (4‐VP) and styrene was synthesized by radical mass polymerization using 2,2′‐azobisisobutyronitrile as initiator. An insoluble (linear) pyridinium‐type polymer was prepared by the reaction of P (4VP–St) with 1‐bromooctane. An anion exchange membrane was prepared using a composite of pyridinium‐type polymer and a fibrous woven structure for use in electrochemistry. The composite membrane was characterized by X‐ray diffraction, tensile strength, scanning electron microscopy, and electrochemistry measurements. The experimental results showed that the fibrous woven product had improved the tensile strength more than had the membrane made of a pyridinium‐type polymer alone. The composite membrane was used in alkaline fuel cells, and its properties were measured by electrochemical analysis. The ionic conductivity of the membrane was acceptable, but its performance as a direct methanol fuel cell (DMFC) was not. The primary reason for this was analyzed, and research is ongoing, with analysis to be discussed in later reports. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2248–2251, 2006
Curing kinetics and structural changes of a of di[(N‐m‐acetenylphenyl) phthalimide] ether/[(methyl) diphenylacetylene] silane copolymer
Authors: Dai Zeliang , Chen Qi , Ni Lizhong , Song Ning , Zhang Wenkai
Published: February 2006

Differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, and 13C‐NMR were used to characterize the curing kinetics and structural changes of a copolymer of di[(N‐m‐acetenylphenyl) phthalimide] ether (DAIE) and [(methyl) diphenylacetylene] silane (MDPES). The results show that the apparent activation energy (E) and reaction order (n) calculated according to the Kissinger method were nearly the same as those calculated according to the Ozawa method. E was 160.4 kJ/mol and n was 0.96 with the Kissinger method, and E was 158.1 kJ/mol and n was 0.95 with the Ozawa method. The FTIR and solid‐state 13C‐NMR results also indicate that with increasing curing temperature, the peaks assigned to SiH and CC bonded to phenylene carbons decreased, broadened, and finally vanished, whereas the peaks assigned to the CC carbons and phenyl carbons increased and broadened. Crosslinking reactions in the curing of the DAIE/MDPES copolymer were possible due to the hydrosilylation reaction and the Diels–Alder reaction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2126–2130, 2006
Miscibility and thermooxidative degradation of poly(vinyl chloride)/biodegradable aliphatic–aromatic copolyester blends
Authors: Andričić Branka , Kovačić Tonka , Klarić Ivka
Published: February 2006

The miscibility of poly(vinyl chloride) (PVC) and a biodegradable aliphatic–aromatic copolyester (AAC) was investigated by differential scanning calorimetry. The thermooxidative degradation of the blends was investigated thermogravimetrically. The blends were prepared by dissolution in 1,2‐dichloroethane and precipitation with methanol. The investigated blends were completely miscible with the glass‐transition temperatures best predicted by the Fox equation. Fourier transform infrared analysis showed that the interactions responsible for miscibility were the hydrogen bonds between the blend components. The thermooxidative stability of the PVC/AAC blends was improved compared to that of pure PVC. Furthermore, when AAC was added, the dehydrochlorination rate of PVC decreased, and the maximum rate shifted to a higher temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2158–2163, 2006
Comparative study of propylene polymerization using monosupported and bisupported titanium‐based Ziegler–Natta catalysts
Authors: Zohuri Gholam Hossien , Jamjah Roghieh , Ahmadjo Saeid
Published: February 2006

Heterogeneous Ziegler–Natta systems—MgCl2 (ethoxide type)/TiCl4/di‐n‐butyl phthalate (DNBP)/triethylaluminum (TEA)/dimethoxymethylcyclohexylsilane (DMMCHS) and SiO2/MgCl2 (ethoxide type)/TiCl4/DNBP/TEA/DMMCHS—were studied for the polymerization of propylene. The slurry polymerization of propylene was carried out with the catalyst systems in n‐heptane. Both systems performed with optimum activity at a particular [Al]/[DMMCHS]/[Ti] molar ratio. The ratio to reach the highest activity was much lower for the bisupported catalyst system. The productivity of the bisupported catalyst was higher than that of the monosupported one. Polypropylene of a high isotacticity index (II; >96%) was obtained with both systems and did not significantly change with an increasing [Al]/[DMMCHS]/[Ti] molar ratio. The addition of hydrogen as a chain‐transfer agent reduced II of the polymers obtained with both systems. The effect of the polymerization temperature (40–75°C) on the viscosity‐average molecular weight (Mv) and II showed a decrease in both cases. The bisupported catalyst system produced a polymer with higher Mv. The effect of temperature on II was similar for both the monosupported and bisupported systems. A monomer pressure of 2.02 × 105 to 0.8 × 106 Pa increased Mv of the obtained polymer. II of the polymer slightly decreased with increasing monomer pressure. The titanium content of the catalyst was 1.70 and 3.55% for the monosupported and bisupported systems, respectively. The surface area of the bisupported catalyst was higher than that of the monosupported catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2220–2226, 2006
Production of agrochemical from waste polyesters
Authors: Goje A. S. , Shinde P. H. , Mishra S.
Published: February 2006

In this study, agrochemical was produced from waste polyesters. Reactions of waste polyesters [poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT)] powder with ethylene glycol (EG) in the presence of tetrahydrofurane (THF) using 0.003 mol lead acetate as a catalyst were carried out in a batch reactor at 470 K and at atmospheric pressure conditions. Reactions were undertaken with various particle size ranges from 50 to 512.5 μm, and reaction time from 30 to 70 min for reactions of polyesters. Low molecular weight product of polyester was obtained during this process. In the next stage, hydroxylamine hydrochloride (HAHC), cyclohexylamine (CHA), and potasium hydroxide (KOH) solution were introduced to convert low molecular weight product of polyester into terephthalohydroxamic acid (TPHA) by introduction of HCl (Hydrochloric Acid) as per stoichiometric requirement. TPHA can be used as an agrochemical (insecticide) with appreciable efficiency. To increase the polyester conversion rate, external catalyst (0.003 mol lead acetate) was introduced during the reaction. The product was deposited on the surface of unreacted polyester, which was removed from the surface by introducing dimethyl sulfoxide (DMSO). To accelerate the reaction rate, DMSO, CHA, and THF were introduced during the reaction, which has an industrial significance. Depolymerization of polyester was proportional to the reaction time. Depolymerization of polyester was inversely proportional to the particle size of polyester. Analyses of value‐added product (TPHA) and byproducts [EG and BD (1,4‐butanediol)] as well as polyesters were undertaken. A kinetic model is developed, and experimental data simulated with it, which was consistent with the model. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2504–2510, 2006
Chemistry of thermal ageing in aerospace epoxy composites
Authors: Bondzic S. , Hodgkin J. , Krstina J. , Mardel J.
Published: February 2006

The detailed chemical reactions involved in the thermal ageing (at 120°C) of a typical aerospace epoxy composite have been studied by the mid‐Fourier transform infrared spectroscopy (FTIR) spectral characterization of selected model compounds. The FTIR spectra indicate that at this particular temperature, the major reaction in the resin structure is probably an oxidation of a CH2 group adjacent to the nitrogen atom of the tetraglycidyldiaminodiphenyl methane unit of the molecular structure, particularly where it is attached to one isomer of the diaminodiphenylsulfone hardener unit. The FTIR changes indicate that the major product is an amide group but other minor changes are also detailed and differences in the chemical changes seen at other ageing temperatures highlighted. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2210–2219, 2006
Improving the physical and chemical functionality of starch‐derived films with biopolymers
Authors: Ban Weiping , Song Jianguo , Argyropoulos Dimitris S. , Lucia Lucian A.
Published: February 2006

The physical and chemical properties of composite starch‐based films containing cellulosic fiber, chitosan, and gelatin were investigated. Films containing both cellulosic fibers and chitosan demonstrated tremendous enhancements in film strength and gas permeation. The water absorbency of composite films could be greatly reduced in film composites containing cellulosic fibers and gelatin, but the inclusion of chitosan into these films provided a higher hydrophilicity, increasing water absorbency. Film transparency was not noticeably affected in the composite films that were made. These films may have wide application in the food packaging, agricultural mulching, and the medical industries. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2542–2548, 2006
Structure and adhesion properties of linear low‐density polyethylene powders grafted with acrylic acid via ultraviolet light
Authors: Lei Jingxin , Gao Jun , Jiang Lingbo
Published: February 2006

The structure and adhesion properties of linear low‐density polyethylene (LLDPE) powder grafted with acrylic acid (AA) via ultraviolet light (UV) were studied by Fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and water contact angle, peel strength, and graft degree measurements. The results show that the chemically inert LLDPE powder can be graft‐copolymerized with AA via this photografting method. The graft degree increases with the ultraviolet irradiation time. The hydrophilicity of the grafted LLDPE powder and the peel strength of high‐density polyethylene (HDPE)/steel joint with the grafted LLDPE powder used as hot‐melt adhesive are improved considerably, as compared to that with the ungrafted LLDPE powder. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2549–2553, 2006
Properties of starch‐based blend films using citric acid as additive. II
Authors: Yoon Soon‐Do , Chough Sung‐Hyo , Park Hye‐Ryoung
Published: February 2006

Starch/polyvinyl alcohol (PVA) blend films were prepared by using corn starch, polyvinyl alcohol (PVA), glycerol (GL), and citric acid (CA) as additives and glutaraldehyde (GLU) as crosslinking agent for the mixing process. The additives, drying temperature, and the influence of crosslinker of films on the properties of the films were investigated. The mechanical properties, tensile strength (TS), elongation at break (% E), degree of swelling (DS), and solubility (S) of starch/PVA blend film were examined adding GL and CA as additives. At all measurement results, except for DS, the film adding CA was better than GL because hydrogen bonding at the presence of CA with hydroxyl group and carboxyl group increased the inter/intramolecular interaction between starch, PVA, and additives. CA improves the properties of starch/PVA blend film compared with GL. TS, % E, DS, and S of film adding GLU as crosslinking agent were examined. With increasing GLU contents, TS increases but % E, DS, and S value of GL‐added and CA‐added films decrease. When the film was dried at low temperature, the physical properties of the films were clearly improved because the hydrogen bonding was activated at low temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2554–2560, 2006
Lymphangiogenesis by blind‐ended vessel sprouting is concurrent with hemangiogenesis by vascular splitting
Authors: Parsons‐Wingerter Patricia , Mckay Terri L. , Leontiev Dmitry , Vickerman Mary B. , Condrich Terence K. , Dicorleto Paul E.
Published: February 2006

Development of effective vascular therapies requires the understanding of all modes of vessel formation involved in angiogenesis (here termed “hemangiogenesis”) and lymphangiogenesis. Two major modes of vessel morphogenesis include sprouting of a new vessel from a preexisting vessel and splitting of a preexisting parent vessel into two offspring vessels. In the quail chorioallantoic membrane (CAM) during mid‐development (embryonic days E6–E9), lymphangiogenesis progressed primarily via blind‐ended vessel sprouting. Isolated lymphatic endothelial progenitor cells were recruited to the tips of growing vessels. During concurrent hemangiogenesis, parent blood vessels expanded from the capillary network and split into offspring vessels, accompanied by transient capillary expression of alpha smooth muscle actin (αSMA) and recruitment of polarized mural progenitor cells. Lymphatics and blood vessels were identified by confocal/fluorescence microscopy of vascular endothelial growth factor (VEGF) receptor VEGFR‐2, αSMA (specific to CAM blood vessels), homeobox transcription factor Prox1 (specific to lymphatics), and the quail hematopoetic marker, QH‐1. VEGFR‐2 was expressed intensely in isolated cells and lymphatics, and moderately in blood vessels. Prox1 was absent from isolated progenitor cells prior to lymphatic recruitment. Exogenous vascular endothelial growth factor‐165 (VEGF165) increased blood vessel density and anastomotic frequency without changing endogenous modes of vascular/lymphatic vessel formation or marker expression. Although VEGF165 is a key cellular regulator of hemangiogenesis and vasculogenesis, the role of VEGF165 in lymphangiogenesis is less clear. Interestingly, VEGF165 increased lymphatic vessel diameter and density as measured by novel Euclidean distance mapping, and the antimaturational dissociation of lymphatics from blood vessels, accompanied by lymphatic reassociation into homogeneous networks. Published 2006 Wiley‐Liss, Inc.