bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of a Mission-Based Flight Priority System
Authors: Yaylalı Emine , Yıldız Feride Şüheda , Koçak Sena
Published: March 2024

Purpose: The purpose of this study is to develop a mission-based flight priority system that decides which aircraft would match with which airborne operation, and determines a sequence of take-off for those airplane-operation peers. Both peers and take-off orders are specified by minimizing total operation cost which includes fuel cost, waiting cost and penalty cost for missed missions. The aim of this system is to create a cost effective, fast and efficient decision-making tool for allocating operation-aircraft assignments and determining the sequence of take-off, especially in emergency cases.
Methodology: An integer programming model that minimizes the total cost are formulated. Four scenarios are designed to assess the performance of the system. The system, which includes five aircrafts and ten airborne operations, was revealed in the study. Integer programming is used while modeling the system and the Branch-and-Bound algorithm is used as the solution algorithm. The optimization algorithm was developed in MATLAB.
Findings: Both emergency scenarios and normal scenarios are maintained with the purpose of examining the behaviors and the result of the system under different conditions. It is believed that system have given the appropriate sequence and matchup for air vehicle-operation peers.
Originality: Since the integration of airplane-mission assignment and determining take-off sequence is rare in the literature, our study may be considered as a new approach. Therefore, in order to bring a new perspective, an optimization system related to the determination of flight priority and mission assignment was brought in this study.
Evaluation of the Antioxidant Capacity and Studies of the Anticonvulsant Properties of Hymenocardia acida
Authors: Mathieu Melingui Eketi Joel , Lucie Ojong , Omam  , Elisabeth Ngo Bum , Achick Tembe Estella , Roger Ahouga , Hermann Chindje , Nina Nfogham , Pamela Tayou , Marie-Claire Fonyuy , Wilfred Mbacham , Charles Fokunang
Published: March 2024

The work focuses on evaluating the antioxidant capacity and studying the anticonvulsant properties of the bark of Hymencardia acida (Euphorbiaceae), which is a tropical African plant traditionally used in the Centre Region of Cameroon in the treatment of many diseases such as migraines, diarrhoea, wounds, stomach ache and influenza. The various antioxidant tests carried out have highlighted the high antioxidant content of the bark of these plants. The results of the anticonvulsant activity showed that: The decoction of Hymencardia acida antagonized the convulsions induced by 100% pentylenetetrazole at doses of 22.5, 45 and 90 mg/kg. It also protected mice from convulsions induced by pilocarpine, 100% at doses 45 and 90 mg/kg and in the 4-aminopyridine convulsion induction test, it protected mice 100% at doses 45 and 90 mg/kg with a significant difference of (P ≤ 0.001) compared to the negative control. This study justify the use of H. acida in traditional medicine category 1, for the treatment of epilepsy in the community of the Centre Region of Cameroon.
Sample Size Calculation for Comparing Time‐to‐Event Data
Authors: Wang Hansheng , Chow Shein‐Chung
Published: October 2006

This article discusses three commonly employed testing procedures: the exponential model, Cox's proportional hazard model, and the log‐rank test. The sample size formula for testing equality, superiority, and equivalence are discussed for each method.
Predicting Random Effects in Community Intervention
Authors: Stanek Edward J.
Published: October 2006

The main objective in a group randomized trial is a comparison between treatments. Often, interest exists in the expected response for a particular group receiving a treatment. As a random sample of groups is included in the trial, the parameter for such a group is represented as a random effect. In this context, predicting the expected response for a group requires predicting a random effect. Proposed solutions to this problem are reviewed focusing on differences in the model assumptions in a simple setting. The author concludes that although popular computing solutions exist, fundamental open questions remain that impact interpretation.
Steam reactivation of a spent sorbent for enhanced SO2 capture in FBC
Authors: Montagnaro Fabio , Pallonetto Fabio , Salatino Piero , Scala Fabrizio
Published: October 2006

The regeneration by steam hydration of the sulfur capture ability of spent sorbent particles from Fluidized Bed Combustion (FBC) is addressed. The process is characterized in terms of effectiveness of sorbent reactivation, hydration degree, particle sulfation pattern, development of accessible porosity, and extent of particle attrition and fragmentation. Steam reactivation experiments were carried out in a lab‐scale atmospheric FBC at 250°C for 10, 30, and 180 min with 0.05 MPa steam partial pressure. The effectiveness of sorbent reactivation was assessed by reinjecting the reactivated material into the FB reactor operated at 850°C under simulated desulfurization conditions and following the degree of calcium conversion and the attrition rate along with resulfation. The experimental results indicated that steam reactivation is effective in renewing the SO2 uptake ability of the exhausted sorbent particles. The regeneration mechanism based on the swelling upon hydration of the unreacted core, the generation of fissures and cracks, and the consequent development of accessible porosity is confirmed for the limestone under scrutiny. In addition to this, a remarkable result was that steam hydration induces, for the sorbent under investigation, a pronounced sulfur redistribution throughout the particle cross‐section, which provides another pathway to the enhancement of the sulfur capture ability of the reactivated sorbent. © 2006 American Institute of Chemical Engineers AIChE J, 2006
D‐serine in the developing human central nervous system
Authors: Fuchs Sabine A. , Dorland Lambertus , De Sain‐Van Der Velden Monique G. , Hendriks Margriet , Klomp Leo W. J. , Berger Ruud , De Koning Tom J.
Published: October 2006

To elucidate the role of D‐serine in human central nervous system, we analyzed D‐serine, L‐serine, and glycine concentrations in cerebrospinal fluid of healthy children and children with a defective L‐serine biosynthesis (3‐phosphoglycerate dehydrogenase deficiency). Healthy children showed high D‐serine concentrations immediately after birth, both absolutely and relative to glycine and L‐serine, declining to low values at infancy. D‐Serine concentrations were almost undetectable in untreated 3‐phosphoglycerate dehydrogenase–deficient patients. In one patient treated prenatally, D‐serine concentration was nearly normal at birth and the clinical phenotype was normal. These observations suggest a pivotal role for D‐serine in normal and aberrant human brain development. Ann Neurol 2006;60:476–480
Polishing a Diamond in the Rough: “CuH” Catalysis with Silanes
Authors: Rendler Sebastian , Oestreich Martin
Published: October 2006

The value of a novel chemical transformation is often underappreciated at the time of its discovery. The reasons are doubtlessly manifold, but the “chemical zeitgeist” subtly determines how the new reaction will be received by the chemical community. The enantioselective reduction of carbonyls by copper‐catalyzed hydrosilylation was certainly outshone by other asymmetric hydrogenation techniques. A seminal report at an early stage indicated the considerable potential of this catalytic process, yet it was disregarded for more than a decade. A refined mechanistic picture in connection with a plethora of new chiral ligands then led to copper‐catalyzed 1,2‐ as well as 1,4‐reductions of carbonyl compounds with excellent levels of enantioselection at high substrate‐to‐catalyst ratios and even more remarkable substrate‐to‐ligand ratios. The tide is turning for inexpensive copper catalysts in asymmetric hydride transfer reactions!
Analysis of the structure and properties of expanded graphite‐filled poly(phenylene ether)/atactic polystyrene nanocomposite fibers
Authors: Celik Ceyhan , Warner Steven B.
Published: October 2006

A miscible blend of 85.5 wt % atactic polystyrene and 9.5 wt % poly(phenylene ether) containing 5.0 wt % expanded graphite nanoparticles was melt‐spun and stretched up to 25 times. The structure and electrical and mechanical properties of the fibers were investigated. Characterized by a Hermans orientation factor of 0.6, the nanographite platelets were moderately aligned with the fiber axis, which likely occurred when the polymer itself was partially aligned during drawdown. The electrical conductivity of the oriented filaments was about 10−4 S/cm, about what other researchers have measured in comparable unoriented systems. The conductive network of agglomerated graphite nanoparticles did not collapse during drawdown, which led to small protrusions, or bumps, on the fiber surface. The obvious lack of polymer–particle bonding led to reduced extrinsic mechanical properties; both the tensile strength and elongation of the fibers were 20–25% less than those of the neat fibers. The modulus of the oriented fiber was unchanged by the addition of the graphite nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 645–652, 2007
Comparative effect of metallocene and Ziegler‐Natta polypropylene on the exfoliation of montmorillonite and hectorite clays to obtain nanocomposites
Authors: Moncada E. , Quijada R. , Retuert J.
Published: October 2006

The present study was carried out on the effect of molecular weight and polydispersity of polypropylene (PP) obtained via Ziegler‐Natta or metallocene catalysis on the formation of nanocomposites with montmorillonite and mineral and synthetic hectorite. The formation of the nanocomposites was achieved by the melt‐mix method. X‐ray diffraction, transmission electron microscopy, and analysis of mechanical properties showed that, using PP obtained via metallocene catalysis (polydispersity ∼ 2), it is possible to achieve improved formation of nanocomposites compared with PP obtained via Ziegler‐Natta catalysis (polydispersity ∼ 4). It was also found that the molecular weight of the PP affects the tendency toward clay exfoliation and consequently the properties of the nanocomposites. Montmorillonite type clay was evaluated at 1%, 3%, and 5% by weight in the nanocomposite. The nanocomposite with 1 wt % clay was found to have better mechanical properties compared with the nanocomposite containing 3 wt % and 5 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 698–706, 2007
Effect of octene content in poly(ethylene‐co‐1‐octene) on the properties of poly(propylene)/poly(ethylene‐co‐1‐octene) blends
Authors: Lee Hwi‐yong , Kim Dong Hak , Son Younggon
Published: October 2006

Ethylene‐octene random copolymer (EOC) is one of the most commonly employed elastomers for PP, and as such its rubber toughening efficiency has been extensively studied. However, most existing studies employ EOC containing an octene comonomer of about 8 mol %. Therefore, in this study, we investigated the effect of EOC octene comonomer content on the morphology and thermal and mechanical properties of PP‐ethylene random copolymer (PP‐CP)/EOC (80/20 wt %/wt %) blends. It was clearly shown that the properties of the blends are significantly affected by the octene content. The rubber particle size of the blends decreased as the octene content in the EOC was increased, which was a consequence of the reduced interfacial tension between PP‐CP and EOC. Impact strength of the blends as a function of octene content displayed a brittle‐ductile transition. The tensile yield strength and modulus of the PP‐CP/EOC blends were decreased by addition of EOC, owing to incorporation of the soft EOC into the hard PP‐CP. The tensile yield strength and modulus of PP‐CP/EOC blends decreased monotonically with the octene content in the EOC. The melting temperature as well as the crystallinity of the PP‐CP phase were not affected significantly by the addition of EOC whereas a notable shift in melting and crystallization temperatures was observed for the EOC phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1133–1139, 2007
Novel fishnet fibers with anti‐adhesion of seaweeds obtained by UV‐irradiation technique
Authors: Zhao Yi‐Ping , Chen Li , Zhang Huan , Zhao Guo‐Bu
Published: October 2006

A novel Nylon‐6 fishnet fiber with the antiadhesion of seaweeds was prepared by UV radiation‐initiated grafting of acrylic acid (AA) onto Nylon‐6 fibers, and its structure was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The influences of grafting conditions, such as irradiation dose, temperature, concentration of monomer, inorganic acid, and inhibitor etc., on grafting rate were studied, and the antiadhesion of seaweeds was evaluated with Dunaliella. The results showed that the grafting amount of Nylon‐g‐AA was increased with the increase of irradiation time. With the increase of concentration of AA, temperature, reaction time, inorganic acid, and inhibitor, the grafting amount increased firstly and then decreased, respectively. Nylon‐6 fibers modified by Poly(acrylic acid) (PAA) had a strong effect on the adhesion of Dunaliella, and the antiadhesion was improved with the increase of the grafting amount. Results from the mechanical analysis revealed that the tensile strength of the UV‐irradiation fibers decreased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1252–1256, 2007
Preparation and application of fluorocarbon polymer/SiO2 hybrid materials, part 1: Preparation and properties of hybrid materials
Authors: Yeh Jen‐Taut , Chen Chin‐Lai , Huang Kuo‐Shien
Published: October 2006

For this study, we first prepared a fluorocarbon polymer and its hybrid materials. We found that fluorocarbon copolymers can produce hydrogen bonds with SiO2 to form hybrid materials. We also used thermogravimetric analyzer and tested the thermostabilities of the four products, which were ranked as follows: fluorocarbon copolymer/SiO2 hybrid material > fluorocarbon polymer/SiO2 hybrid material > fluorocarbon copolymer > fluorocarbon polymer. In addition, we found that, due to the inorganic SiO2 used, the number of pores and the specific surface areas of the hybrid materials both increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1140–1145, 2007
Development of transdermal drug‐delivery films with castor‐oil‐based polyurethanes
Authors: Shelke Namdev B. , Sairam Malladi , Halligudi Shivaraj B. , Aminabhavi Tejraj M.
Published: October 2006

Two different types of polyurethanes (PUs) were prepared with castor oil, ethylene glycol, isophorene diisocyanate and castor oil, and isophoren diisocyanate and poly‐(ethylene glycol) (400 or 600). PU films were prepared and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and gel permeation chromatography. We prepared transdermal patches by loading different amounts of drug, plasticizer, and penetration enhancer.In vitrodrug permeability through the castor‐oil‐based aliphatic PU patches was examined with a Keshary–Chien diffusion cell. The effect of castor oil on the film‐forming properties and the effect of penetration enhancers on diffusion characteristics of indomethacin (IDM) drug through the castor‐oil‐based PU were investigated. Prolonged release of IDM was observed from the prepared PU patches.In vitrodrug diffusion revealed that slow and prolonged release of IDM was achieved in the absence of penetration enhancers. The use of penetration enhancers showed a significant effect on drug diffusion. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 779–788, 2007
Synthesis and electrochemical polymerization of N‐ethylcarbazole‐bis‐3,4‐etyhlenedioxythiophene‐N‐ethylcarbazole comonomer
Authors: Sarac A. S. , Parlak E. , Sezer E.
Published: October 2006

A new comonomer ECz‐BEDOT‐ECz (EBEE) [ECz: N‐ethylcarbazole‐BEDOT:2,2′‐bis(3,4‐ethyhlenedioxy) thiophene] has been synthesized, characterized, and electropolymerized on Pt and carbon fiber microelectrodes (CFME). The ECz side group of the comonomer plays an important role in determining its physical properties PEBEE and it resembles the behavior of corresponding homopolymer (PECz). PBEDOT was increased by the incorporation of ECz monomer into structure. The environmental stability of PBEDOT was increased by incorporating the ECz unit into the structure. The new comonomer seems prefer to be electrodeposited onto CFME as opposed to Pt. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 795–801, 2007
Emulsion and miniemulsion polymerization of isobornyl acrylate
Authors: Back Alan J. , Schork F. Joseph
Published: October 2006

Isobornyl acrylate, a highly hydrophobic monomer, was batch‐polymerized in both emulsion and miniemulsion recipes. Surfactant levels above and below the critical micelle concentration were used, as were two different initiator types: ionic (potassium persulfate) and nonionic (t‐butyl hydroperoxide) Samples were analyzed for degree of conversion, molecular weight, and particle size. The effects of reaction type (emulsion versus miniemulsion), surfactant level, type of initiator (ionic versus nonionic) of the polymer properties are discussed. Issues of monomer transport across the aqueous phase, and mechanisms of nucleation, especially at very low surfactant concentrations are discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 819–833, 2007
Synthesis and characterization of poly(ethylene terephthalate)/attapulgite nanocomposites
Authors: Yuan Xuepei , Li Chuncheng , Guan Guohu , Liu Xiaoqing , Xiao Yaonan , Zhang Dong
Published: October 2006

A kind of clay with fibrous morphology, attapulgite (AT), was used to prepare poly (ethylene terephthalate) (PET)/AT nanocomposites via in situ polymerization. Attapulgite was modified with Hexadecyltriphenylphosphonium bromide and silane coupling agent (3‐glycidoxypropltrimethoxysilane) to increase the dispersion of clay particles in polymer matrix and the interaction between clay particles and polymer matrix. FTIR and TGA test of the organic‐AT particles investigated the thermal stability and the loading quantity of organic reagents. XRD patterns and SEM micrographs showed that the organic modification was processed on the surface of rod‐like crystals and did not shift the crystal structure of silicate. For PET/AT nanocomposites, it was revealed in TEM that the fibrous clay can be well dispersed in polymer matrix with the rod‐like crystals in the range of nanometer scale. The diameter of rod‐like crystal is about 20 nm and the length is near to 500 nm. The addition of the clay particles can enhance the thermal stability and crystallization rate of PET. With the addition of AT in PET matrix, the flexural modulus of those composites was also increased markedly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1279–1286, 2007
Mechanical and thermal properties of epoxypolymethyl methacrylate blends synthesizedin supercritical carbon dioxide
Authors: Zaidi M. G. H. , Bhullar N. , Singh V. P. , Sah P. L. , Alam S. , Singh R.
Published: October 2006

A series of epoxy/polymethyl methacrylate (E/PMMA) blends was synthesized through impregnation polymerization of methyl methacrylate at concentrations ranging (0–1.5 phr) into diglycidyl ether of bisphenol‐A (0.1 mol) in presence of 2,2‐azobisisobutyronitrile (2 × 10−2 mol) at 3000 psi, (60–90 ± 1)°C for 3 h in supercritical carbon dioxide, followed by curing of treated epoxy with triethylene tetramine (10 phr) at (40 ± 1)°C. The progress of all such impregnation polymerization reactions was monitored rheoviscometrically. Formation of E/PMMA blends was ascertained through of PMMA mass uptake (%) into epoxy, UV–vis and FTIR spectra, and TEM. With PMMA mass uptake (%), compression strength and resistance against wear of E/PMMA blends were increased with simultaneous decrease in their Rockwell hardness (R scale), charpy impact, and tensile strength, respectively. All E/PMMA blends have shown nonuniform photoelastic behavior at applied load ranging 4–20 kgf and significant stability against thermooxidation with Tg/Tm and char yield (%) ranging 0.53–0.59, 29.31–31.66, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1303–1310, 2007
Synthesis and biodegradability evaluation of 2‐methylene‐1,3‐dioxepane and styrene copolymers
Authors: Xu Jian , Liu Zhi‐Lan , Zhuo Ren‐Xi
Published: October 2006

Biodegradable copolymers of 2‐methylene‐1,3‐dioxepane (MDO) and styrene (ST) were synthesized by free‐radical copolymerization using di‐t‐butyl peroxide (DTBP) as the initiator. The copolymers containing ester units were characterized by Fourier transform infrared (FTIR), 1H‐NMR, and 13C‐NMR spectroscopy. Their molecular weight and polydispersity index were determined by gel permeation chromatography (GPC). In vitro enzymatic degradation of poly(MDO‐co‐ST) was performed at 37°C in phosphate buffer solution (PBS, pH = 7.4) in the presence of Pseudomonas lipase or crude enzyme extracted from earthworm. The experiment showed that incorporating ester units into CC backbone chain of polystyrene would result in a biodegradable copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1146–1151, 2007
Isothermal crystallization kinetics and morphology development of isotactic polypropylene blends with atactic polypropylene
Authors: Chen Jean‐Hong , Chang Yu‐Lun
Published: October 2006

The crystallization kinetics and morphology development of pure isotactic polypropylene (iPP) homopolymer and iPP blended with atactic polypropylene (aPP) at different aPP contents and the isothermal crystallization temperatures were studied with differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy. The spherulitic morphologies of pure iPP and larger amounts of aPP for iPP blends showed the negative spherulite, whereas that of smaller amounts of aPP for the iPP blends showed a combination of positive and negative spherulites. This indicated that the morphology transition of the spherulite may have been due to changes the crystal forms of iPP in the iPP blends during crystallization. Therefore, with smaller amounts of aPP, the spherulitic density and overall crystallinity of the iPP blends increased with increasing aPP and presented a lower degree of perfection of the γ form coexisting with the α form of iPP during crystallization. However, with larger amounts of aPP, the spherulitic density and overall crystallinity of the iPP blends decreased and reduced the γ‐form crystals with increasing aPP. These results indicate that the aPP molecules hindered the nucleation rate and promoted the molecular motion and growth rate of iPP with smaller amounts of aPP and hindered both the nucleation rate and growth rate of iPP with larger amounts of aPP during isothermal crystallization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1093–1104, 2007
Highly crosslinked nanocomposites of aromatic dicyanates/SiO2 via the sol–gel method
Authors: Lin Rong‐Hsien , Lin Chih‐Wei , Lee An‐Cheng , Chen Yi‐Hung , Yen Fu‐Shan
Published: October 2006

Highly crosslinked nanocomposites of bisphenol A dicyanate (BADCy) containing silica clusters were successfully prepared via the sol–gel process. The silica clusters were generated from various metal alkoxide precursors, including methyltrimethoxysilane (TMOS), 3‐glycidoxypropyltrimethoxysilane (GPOS), and 2‐(3,4‐epoxycyclohexyl) ethyltrimethoxysilane (ECOS). The metal alkoxide precursors GPOS and ECOS were, in turn, used as coupling agents. Three kinds of systems involving BADCy/TMOS, BADCy/coupling agent, and BADCy/TMOS/coupling agent were individually prepared and thoroughly investigated using various methods. Each kind of system was of a particular characterization and morphology and had distinct physical and dielectric properties. Isolated silica clusters on a nanoscale were homogenously distributed in the highly crosslinked BADCy/TMOS hybrid system. The characterization of BADCy/TMOS nanocomposites showed improved physical properties, when compared with the neat BADCy network. The particle sizes can be controlled by adding different amounts of TMOS and are slightly increased (in the range of 50–105 nm) with increasing TMOS content. On the other hand, in the highly crosslinked BADCy/coupling agent hybrid system, the silica clusters were tethered to the BADCy matrix by the coupling agent. An oxazoline linkage was detected during the reaction of cyanate groups in BADCy with the epoxide groups in the coupling agent. These nanocomposites exhibited weakened mechanical properties but are of a smaller and more homogenous particle size in the range of 30–50 nm, irrespective of the silica content. Finally, the BADCy/TMOS/coupling agent system was successfully designed to combine the advantages of the two systems mentioned above. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1356–1366, 2007
Remodeling dynamics in the alveolar process in skeletally mature dogs
Authors: Huja Sarandeep S. , Fernandez Soledad A. , Hill Kara J. , Li Yan
Published: October 2006

Bone turnover rates can be altered by metabolic and mechanical demands. Due to the difference in the pattern of loading, we hypothesized that there are differences in bone remodeling rates between the maxillary and mandibular alveolar processes. Furthermore, in a canine model, the alveolar process of teeth that lack contact (e.g., second premolars) would have a different turnover rate than bone supporting teeth with functional contact (e.g., first molars). Six skeletally mature male dogs were given a pair of calcein labels. After sacrifice, specimens representing the anterior and posterior locations of both jaws were prepared for examination by histomorphometric methods to evaluate the bone volume/total volume (BV/TV; %), bone volume (mm2), mineral apposition rate (MAR; μm/day), and bone formation rate (BFR; %/year) in the alveolar process. There were no significant differences (P > 0.05) in the BV/TV within the jaws. The bone volume within the alveolar process of the mandible was 2.8‐fold greater than in the maxilla. The MAR was not significantly different between the jaws and anteroposterior locations. However, the BFR was significantly (P < 0.0001) greater in the mandible than in the maxilla. The anterior location had higher (P = 0.002) remodeling than the posterior location in the maxilla but not in the mandible. While there was a greater bone mass and increased remodeling in the mandible, no remodeling gradient in the coronal‐apical direction was apparent in the alveolar process. Bone adaptation probably involves a complex interplay of bone turnover, mass, and architecture. Anat Rec Part A, 2006. © 2006 Wiley‐Liss, Inc.
Manipulating the evocative and abative effects of an establishing operation: influences on challenging behavior during classroom instruction
Authors: O'Reilly Mark , Edrisinha Chaturi , Sigafoos Jeff , Lancioni Giulio , Cannella Helen , Machalicek Wendy , Langthorne Paul
Published: October 2006

In this study we examined the evocative and abative effects of an establishing operation on challenging behavior during classroom instruction for a student with severe disabilities including autism. A prior functional analysis indicated that his challenging behavior was maintained by access to preferred snack items. During classroom instructional sessions these snack items were visible but not available to the student. In other words challenging behavior was placed on extinction during instruction. Immediately prior to instructional sessions the student received either access to snack items or did not receive access to snacks. Access versus no access to snacks prior to instruction was systematically controlled using a multi‐element design. Results demonstrated higher levels of challenging behavior during instruction when the student did not have access to snacks prior to instruction. Very little challenging behavior occurred during instructional sessions when the student had prior access to snacks. Implications for considering the evocative and abative effects of establishing operations when implementing operant extinction in applied settings are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Cover Picture: Hierarchical Mechanochemical Switches in Angiostatin (ChemBioChem 11/2006)
Authors: Grandi Fabio , Sandal Massimo , Guarguaglini Giovanni , Capriotti Emidio , Casadio Rita , Samorì Bruno
Published: October 2006

The cover picture addresses a very general and basic question: is the active form of a protein only ever the native one? The single‐molecule experiments reported in the article by Samorì et al. on p. 1774 ff indicate that angiostatin is present in vivo not only in its native, fully oxidized and folded structure, but in a series of partially reduced and partially unfolded structures. Access to these structures is controlled by the coupling of redox and mechanical switches, depicted on the cover figure for the K2–K3 fragment of this multimodular protein. If we assume that these structures, rather than the native one, can act as the active forms of this protein, a set of puzzling and so far unexplained data on the antiangiogenic activity of angiostatin can be accounted for. AFM‐based single‐molecule force spectroscopy was used in this study, and one of the recorded force curves is shown in the background of the picture.
Organoiodine(III)‐mediated efficient synthesis of new 3,9‐diaryl‐bis‐1,2,4‐triazolo[4,3‐a][4,3‐c]pyrimidines
Authors: Prakash Om , Kumar Rajesh , Sharma Deepak , Naithani Rajesh , Kumar Ravi
Published: October 2006

Oxidation of bis‐2,4‐pyrimidinylhydrazones of various araldehydes with two equivalents of iodobenzene diacetate in dichloromethane provides an efficient and easy method for the synthesis of eight new 3,9‐diaryl‐bis‐1,2,4‐triazolo[4,3‐a][4,3‐c]pyrimidines. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:653–655, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20250
Derivation techniques on the Hermitian surface
Authors: Cossidente A. , Ebert G. L. , Marino G.
Published: October 2006

We discuss derivation‐like techniques for transforming one locally Hermitian partial ovoid of the Hermitian surface H(3,q2) into another one. These techniques correspond to replacing a regulus by its opposite in some naturally associated projective 3‐space PG(3,q) over a square root subfield. © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 478–486, 2007
The zebrafish genome in context: ohnologs gone missing
Authors: Postlethwait John H.
Published: October 2006

Some zebrafish genes appear to lack an ortholog in the human genome and researchers often call them “novel” genes. The origin of many so‐called “novel” genes becomes apparent when considered in the context of genome duplication events that occurred during evolution of the phylum Chordata, including two rounds at about the origin of the subphylum Vertebrata (R1 and R2) and one round before the teleost radiation (R3). Ohnologs are paralogs stemming from such genome duplication events, and some zebrafish genes said to be “novel” are more appropriately interpreted as “ohnologs gone missing”, cases in which ohnologs are preserved differentially in different evolutionary lineages. Here we consider ohnologs present in the zebrafish genome but absent from the human genome. Reasonable hypotheses are that lineage‐specific loss of ohnologs can play a role in establishing lineage divergence and in the origin of developmental innovations. How does the evolution of ohnologs differ from the evolution of gene duplicates arising from other mechanisms, such as tandem duplication or retrotransposition? To what extent do different major vertebrate lineages or different teleost lineages differ in ohnolog content? What roles do differences in ohnolog content play in the origin of developmental mechanisms that differ among lineages? This review explores these questions. J. Exp. Zool. (Mol. Dev. Evol.) 308B:563–577, 2007. © 2006 Wiley‐Liss, Inc.
Quantitative analysis of cotransfection efficiencies in studies of ionotropic glutamate receptor complexes
Authors: Ma Zhan‐Lu , Werner Markus , Körber Christoph , Joshi Illah , Hamad Mohammad , Wahle Petra , Hollmann Michael
Published: October 2006

Transient transfection of cultured mammalian cells is widely employed in the study of ionotropic glutamate receptors. Heteromeric expression is usually achieved by simultaneous transfection of various combinations of glutamate receptor subunit‐encoding cDNAs. This approach is based on an “all‐or‐none” assumption, rarely verified experimentally, that any given cell expresses all subunits present during transfection. A similar assumption implicitly is made when cotransfection of a cDNA encoding a fluorescent marker protein is applied to distinguish transfected from untransfected cells. A further frequent assumption alleges that the ratio between cDNAs used in cotransfection experiments directs the assembly of receptor complexes in heterologous expression systems. To check the validity of these assumptions for ionotropic glutamate receptors as model transmembrane receptors, we generated fluorescently labeled receptor subunits and introduced them into HEK‐293 cells by the calcium phosphate method. Analyzing the expression of multiple fusion proteins by confocal microscopy, we evaluated the coexpression efficiencies for various glutamate receptor cDNA combinations, cDNA amounts, and cDNA ratios. Several factors were found to influence the individual, cumulative, and cotransfection efficiencies, including the cDNA ratio, the nature of the expressed protein, and the specific combination of cotransfected cDNAs. After simultaneous transfection with equal amounts of several cDNAs, we demonstrate the consistent generation of several distinct populations of cells that express different receptor subunit combinations. The evidence we present suggests that cotransfected cells should always be independently tested for the expression of all target subunits before picking cells for the analysis of specific heteromeric receptor assemblies. © 2006 Wiley‐Liss, Inc.
Gulf war‐related trauma and psychological distress of Kuwaiti children and their mothers
Authors: Hadi Fawzyiah , Llabre Maria Magdalena , Spitzer Susan
Published: October 2006

The participants were 111 Kuwaiti boys and girls and 59 mothers assessed in 1993 and 2003 to determine exposure to war‐related trauma during the Iraqi occupation and subsequent psychological distress. Children were classified into four groups based on what happened to their fathers during the occupation: killed, missing, arrested, or unharmed. The results indicate that the group whose fathers were arrested had the highest level of posttraumatic stress symptoms and the highest level of depression and anxiety in 2003. In 1993, the highest levels of depression for children and their mothers were observed in those whose fathers–husbands were killed or missing relative to controls. Long‐term effects of war‐related trauma in children may be influenced by the war experience of their fathers.
Kinetics and mechanism of oxidation of indole by HSO
Authors: Meenakshisundaram Subbiah , Sarathi N.
Published: October 2006

Mechanistic studies on the oxidation of indole [IND] by HSO in aqueous CH3CN medium (80:20 v/v) have been carried out, and the reaction is characterized by the rate law −d[HSO]/dt = k[IND][HSO]HSO and SO are probably the respective electrophiles in acidic and basic mediums. Nucleophilic attack of the ethylenic bond on the persulfate oxygen is envisaged to explain the reactivity. The reaction fails to initiate polymerization, and a radical mechanism is ruled out. Thermodynamic parameters very much suggest a bimolecular process. No significant catalytic activity is observed for the reaction system in the presence of Ag+, Cu2+, and heteroaromatic N‐bases. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 39: 46–51, 2007
Kinetics of Demixing and Remixing Transitions in Aqueous Solutions of Poly(N‐isopropylacrylamide): A Temperature‐Jump1H NMR Study
Authors: Yushmanov Pavel V. , Furó István , Iliopoulos Ilias
Published: October 2006

Summary:The time course of the coil‐to‐globule collapse and intermolecular aggregation of poly(N‐isopropylacrylamide) in aqueous solution upon exceeding the lower critical solution temperature (LCST) are investigated by temperature‐jump1H NMR spectroscopy. After the temperature jump, we record the time dependences of (i) the mobile fraction of the polymer chain as revealed by the intensity of the liquid‐like NMR signal, (ii) the local mobility of those chains as revealed by the transverse relaxation timeT2, and (iii) their self‐diffusion coefficientD. The same data are also reported at their temperature‐dependent long‐time limits. The results suggest a sudden, faster than one second, collapse and intermolecular aggregation into globules and a slower reorganization/redistribution of the individual chains among and within the globular and mobile states. We found that all molecular changes are reversible if the temperature remains less than ca. 6–8 K above the LCST for less than a few minutes; under those conditions, experiments upon sudden temperature quench below the LCST show that the aggregates disintegrate and swell into coils in less than a few seconds.

1H NMR signal intensity of the methyl groups of 1 wt.‐% PNIPAM dissolved in 0.1MNaCl solution in D2O in a temperature‐jump experiment from 300 to 312 K. The data were recorded by the 90°−τ–(180°−2τ‐)n‐detection of the CPMG pulse sequence.

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1H NMR signal intensity of the methyl groups of 1 wt.‐% PNIPAM dissolved in 0.1MNaCl solution in D2O in a temperature‐jump experiment from 300 to 312 K. The data were recorded by the 90°−τ–(180°−2τ‐)n‐detection of the CPMG pulse sequence.
Polymerization of Methyl Acrylate by a 2,6‐Bis(2‐benzimidazyl)pyridine Zirconium Dichloride/MAO Catalyst System
Authors: Cho Hyun Yong , Tarte Naresh Hiraral , Cui Liqiang , Hong Dae Sik , Woo Seong Ihl , Gong Young‐Dae
Published: October 2006

Summary: A novel non‐metallocene Zr(IV) complex bearing a bianionic form of the ligand 2,6‐bis(2‐benzimidazolyl)pyridine is synthesized. This Zr complex is an active catalyst for the polymerization of MA via coordination polymerization in the presence of methylaluminoxane MAO. The activity and MWD are increased as the polymerization temperature increases. The maximum activity is observed at Al/Zr molar ratio of 100 and the deactivation is shown above 100, resulting from an inactive bimetallic complex between catalyst and free TMA presented in MAO. Decrease in MWD is observed with higher MAO concentration due to its role in chain transfer during the chain propagation.

The reaction of the ligand and catalyst synthesis.

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The reaction of the ligand and catalyst synthesis.
Cell cycle analysis and interspecies nuclear transfer of in vitro cultured skin fibroblasts of the Siberian tiger (Panthera tigris Altaica)
Authors: Hashem Md. Abul , Bhandari Dilip P. , Kang Sung Keun , Lee Byeong Chun
Published: October 2006

The present study was conducted to examine the effect of cell culture conditions, antioxidants, protease inhibitors (PI), and different levels of dimethylsulfoxide (DMSO) for the promotion of synchronization of different cell cycles of Siberian tiger skin fibroblasts. We also compared the ability of somatic cell nuclei of the Siberian tiger in pig cytoplasts and to support early development after reconstruction. Cell cycle synchronization between nuclear donor and recipient cells is considered to be one of the most crucial factors for successful cloning. Five experiments were performed each with a one‐way completely randomized design involving three replicates of all treatments. Least significant difference (LSD) was used to determine variation among treatment groups. Experiment I focused in the effects of cycling, serum starved and fully confluent stages of Siberian tiger cells on different cell cycles. In Experiment II, the effects of different antioxidants like β‐Mercaptoethanol (β‐ME, 10 µM), cysteine (2 mM), and glutathione (2 mM) were examined after cells were fully confluent without serum starvation for 4 hr. In Experiment III, three PI, namely 6‐dimethylaminopurine (6‐DMAP, 2 mM), cycloheximide (7.5 µg/ml) and cytochalasin B (7.5 µg/ml) were used in the sane manner as in Experiment II. In Experiment IV, different levels of DMSO at 0%, 0.5%, 1.0%, and 2.5% were tested on different cell cycle stages of Siberian tiger examined by Flowcytometry (FACS). In Experiment I, 67.2% of the Siberian tiger skin fibroblasts reached the G0/G1stage (2C DNA content) in fully confluent conditions which was more than the cycling (49.8%) and serum starved (SS) medium (65.5%;P < 0.05). Among the chemically treated group, glutathione (72.6%) and cycloheximide (71.3%) had little bit better results for the synchronization of G0 + G1phases than serum starved and fully confluent. After nuclear transfer we did not see any significant differences on the development of tiger‐porcine reconstructed embryos at cycling, SS and fully confluent. Data indicate that prolonged culture of cells in the absence of serum as well as using different chemicals for this experiment does not imply a shift in the percentage of cells that enter G0/G1and that confluency is sufficient to induce quiescence. This finding can be beneficial in nuclear transfer programs in Siberian tiger, because there are negative effects, such as apoptosis associated with serum starvation. Mol. Reprod. Dev. 74: 403–411, 2007. © 2006 Wiley‐Liss, Inc.
Survivin acts as anti‐apoptotic factor during the development of bovine pre‐implantation embryos
Authors: Park Sae Young , Kim Eun Young , JeOn Kilsoo , Cui Xiang‐Shun , Lee Won Don , Kim Nam‐Hyung , Park Se Pill , Lim Jin Ho
Published: October 2006

Survivin, an inhibitor of apoptotic protein containing a single baculoviral inhibit apoptotic protein repeat domain, is a bifunctional protein that suppresses apoptosis and regulates cell division. Thus, we used double stranded RNA (dsRNA) interference to manipulate survivin expression in bovine embryos and analyze its role in blocking apoptosis and facilitating development of pre‐implantation embryos. In vitro fertilized embryos (1‐cell) were injected with survivin dsRNA, and expression of survivin mRNA was evaluated by real‐time quantitative RT‐PCR. To analyze survivin protein expression, we performed immunocytochemistry using a rabbit anti‐bovine suvivin antibody. Expression levels of survivin mRNA and protein were decreased in the dsRNA group compared to the sham group. Rates of in vitro blastocyst development were lower in the survivin dsRNA‐injected group than in the sham‐injected group. Also, the total cell number seen in blastocysts was decreased in the dsRNA group. TUNEL assays of DNA fragmentation indicated an increased apoptotic index in the dsRNA group compared to the sham group. These results indicate that survivin is important for optimal development of bovine blastocysts and confirm that survivin expression suppresses apoptosis of pre‐implantation embryos. Mol. Reprod. Dev. 74: 582–590, 2007. © 2006 Wiley‐Liss, Inc.
Numerical instability in linearized planing problems
Authors: Wang Xuelian , Day Alexander H.
Published: October 2006

The hydrodynamics of planing ships are studied using a finite pressure element method. In this method, a boundary value problem (BVP) is formulated based on linear planing theory; the planing ship is represented by the pressure distribution acting on the wetted bottom of the ship, and the magnitude of this pressure distribution is evaluated using a boundary element method. The pressure is discretized using overlapping pressure pyramids, known as tent functions, so that the resulting distribution is piece‐wise continuous in both longitudinal and transverse directions. A set of linear algebraic equations for the determination of the pressure is then established using a collocation technique.

It is found that the matrix of the linear equations is ill conditioned; this leads to oscillatory behaviour of the predicted pressure distribution if the direct solution method of LU decomposition or Gaussian elimination is used to solve the system of linear equations. In the current study, this numerical instability is analysed in detail. It is found that the problem can be addressed by adopting singular value decomposition (SVD) technique for the solution of the linear equations. Using this method, the hydrodynamic results for flat‐bottomed and prismatic planing ships are calculated and a good agreement is demonstrated with Savitsky's empirical relations. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical solution of the heat equation with nonlinear boundary conditions in unbounded domains
Authors: Koleva Miglena , Vulkov Lubin
Published: October 2006

The numerical solution of the heat equation in unbounded domains (for a 1D problem‐semi‐infinite line and for a 2D one semi‐infinite strip) is considered. The artificial boundaries are introduced and the exact artificial boundary conditions are derived. The original problems are transformed into problems on finite domains. The space semi‐discretization by finite element method and the full approximation by the implicit‐explicit Euler's method are presented. The solvability of the full discretization schemes is analyzed. Computational examples demonstrate the accuracy and the efficiency of the algorithms. Also, the behavior of blowing up solutions is examined numerically. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 23: 379–399, 2007
Finite difference approximate solutions for the Cahn‐Hilliard equation
Authors: Khiari N. , Achouri T. , Ben Mohamed M.L. , Omrani K.
Published: October 2006

In this article, we analyze a Crank‐Nicolson‐type finite difference scheme for the nonlinear evolutionary Cahn‐Hilliard equation. We prove existence, uniqueness and convergence of the difference solution. An iterative algorithm for the difference scheme is given and its convergence is proved. A linearized difference scheme is presented, which is also second‐order convergent. Finally a new difference method possess a Lyapunov function is presented. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 23: 437–455, 2007
Symbolic computation of the potential in a nonlinear Schrödinger equation
Authors: Kaçar Ahmet , Terzi̇oğlu Ömer
Published: October 2006

Our purpose in this article is to find a time‐dependent potential of the problem of conducting given initial data to given terminal data in a nonlinear Schrödinger equation. We get a condition for existence of a transferring potential. Using Maple, we give symbolic computations of equations for potential. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 23: 475–483, 2007
Ossification of the interosseous ligaments between the metapodials in horses: a new recording methodology and preliminary study
Authors: Bendrey R.
Published: October 2006

This article presents a methodology for recording and quantifying the ossification of the interosseous ligaments between the metapodials in horses, including a scoring system for defining stages in the development of this lesion. The method is applied to a sample of ten Przewalski's horse skeletons from the National Museum, Prague. This case study demonstrates the nature of this lesion in a sample of unworked animals and presents a preliminary sample for comparison with archaeological assemblages. The results show that the condition can occur in animals that are not worked. They also indicate that age is an important factor in the development of the lesion. The expression of the pathology in this sample appears to be linked to how the weight of the animal acts through the legs, in that it occurs earliest, and is generally more advanced, in the areas that support a greater burden. Copyright © 2006 John Wiley & Sons, Ltd.