bluuebunny/crossref_metadata_2025 huggingface dataset:
Rewetting effects and droplet motion on partially wetted powder surfaces
Authors: Hapgood Karen P. , Nguyen Thanh H. , Hauw Sunarko , Iveson Simon M. , Shen Wei
Published: April 2009

In high shear mixer granulation, the powder is agitated in a vessel while liquid is sprayed onto the powder. Formation of “nuclei” can be predicted using a nucleation regime map. However, this approach assumes that only dry powder enters the spray zone. Industrial granulation processes commonly add 20–50 wt % fluid, and the partially wetted powder recirculates many times through the spray zone. The effect of partially wetted powder re‐entering the spray zone is not currently known. To investigate, droplets were added to a powder bed at controlled separation distances and time intervals. A strong correlation between drop penetration time and droplet motion on the powder bed surface was observed. For fast penetrating systems, nucleation was only slightly affected by the presence of the previous droplet. However, systems with long penetration times showed lateral droplet motion due to Laplace pressure differences. Implications for the nucleation regime map are discussed. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Seasonal modulation of reproductive effort during early pregnancy in humans
Authors: Vitzthum Virginia J. , Thornburg Jonathan , Spielvogel Hilde
Published: April 2009

Life history theory predicts that early pregnancy presents a relatively low cost, uncontested opportunity for a woman to terminate investment in a current reproductive opportunity if a conceptus is of poor quality and/or maternal status or environmental conditions are not propitious for a successful birth. We tested this hypothesis in rural Bolivian women experiencing substantial seasonal variation in workload and food resources. Significant risk factors for early pregnancy loss (EPL) included agropastoralism versus other economic strategies, conception during the most arduous seasons versus other seasons, and increasing maternal age. Anovulation rate (AR) was higher during the most arduous seasons and in older women. Breastfeeding and indicators of social status and living conditions did not significantly influence either risk of EPL or AR. Averaged over the year, anovulation occurred in about 1/4 of the cycles and EPL occurred in about 1/3 of the conceptions. This is the first evidence of seasonality of EPL in a non‐industrialized population, and the first to demonstrate a relationship between economic activities and EPL. These findings suggest that both anovulation and EPL are potential mechanisms for modulating reproductive effort; such “failures” may also be nonadaptive consequences of conditions hostile to a successful pregnancy. In either case, variation in EPL risk associated with different subsistence activities can be expected to influence fertility levels and birth seasonality in both contemporary and past human populations. These consequences of variability in the risk of EPL can impact efforts to understand the sources of variation in reproductive success. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Fertility, body size, and shape: An empirical test of the covert maternal depletion hypothesis
Authors: Nenko Ilona , Jasienska Grazyna
Published: April 2009

In populations with limited resources, high‐reproductive effort may lead to poor nutritional status of the mother (the maternal depletion syndrome), whereas in well‐nourished populations woman's body weight tends to increase after each pregnancy. However, in affluent populations, women's body shape may change due to mobilization of polyunsaturated fatty acids (PUFAs) from the lower parts of their bodies to meet the needs of the developing child (the “covert maternal depletion”). We studied relationships between reproductive history traits and body size and shape for 296 rural, parous women in good nutritional status (mean body mass index, BMI = 27.9, SD = 5.94), aged 22–85 (mean 47.8, SD = 16.34) from southern Poland. Body mass adjusted for age, age of menarche, body height, and similarly adjusted BMI were each positively related to the number of children born by a woman (R = 0.13, P = 0.02 and R = 0.13, P = 0.02, respectively). Waist and hip circumferences, adjusted for confounders, did not show statistically significant relationships with the number of children. Moreover, groups with low and high parity did not significantly differ in hip/BMI and waist/BMI ratios, which were proposed to be indicators of covert form of maternal depletion (after controlling for overall body fatness and age). In conclusion, parity caused a slightly higher body mass and BMI later in life. However, parity did not lead to covert maternal depletion, perhaps because women in this population have relatively high‐dietary intake of PUFAs. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Endocrine mechanisms of primate life history trade‐offs: Growth and reproductive maturation in vervet monkeys
Authors: Whitten Patricia L. , Turner Trudy R.
Published: April 2009

Life history theory predicts that the timing of maturation will result from a trade‐off between growth and the age of first reproduction. This trade‐off and its mechanisms of action are still poorly understood in many species and have not been well studied at the individual level. This study examined hypothesized trade‐offs between growth and reproductive maturation in wild populations of vervet monkeys (Cercopithecus aethiops) from Kenya, East Africa. Individuals were sampled from four populations in widely separated sites differing in temperature, altitude, and rainfall. Biological samples and morphometric measures were collected from 50 adult males, 83 adult females, and 225 juveniles. Gonadal steroids and leptin levels were analyzed by radioimmunoassay of sera from 136 juvenile males and 90 juvenile females. Cross‐sectional profiles of morphometric and endocrine data were used to assess the onset and cessation of growth in relation to sexual maturation. Gonadal steroids were used to assess sexual maturation and breeding onset. Leptin was used as an index of nutritional state. Estimates of mortality were derived from population age‐structure. Across populations, higher resource productivity and nutrient status were associated with more rapid growth. Shorter growth duration was associated with earlier reproductive onset. These findings provide support for models of trade‐offs between the timing of growth completion and reproductive onset, but they are contradicted by the evidence that reproduction precedes the cessation of growth in these populations. The biphasic actions of estradiol provide an alternative model and mechanism for the growth‐reproduction trade‐off. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Influence of helminth infections on childhood nutritional status in lowland Bolivia
Authors: Tanner S. , Leonard W.R. , Mcdade T.W. , Reyes‐Garcia V. , Godoy R. , Huanca T.
Published: April 2009

Infectious disease, such as diarrheal disease, respiratory infections, and parasitic infections, are an important source of nutritional and energetic stress in many populations. Inspired by the research and methodological innovations of A. Roberto Frisancho, this work considers the impact of childhood environment and local disease ecology on child health and nutritional patterns among an indigenous group in lowland Bolivia. Specifically, we examine the association between soil‐transmitted helminth infection, especially hookworm species, and anthropometric markers of short‐ and long‐term nutritional status. Fecal samples, anthropometric dimensions, and health interviews were collected for 92 children ranging in age from 2.0 to 10.9 years. Microscopic examination revealed high levels of parasitic infection, with 76% of children positive for hookworm species infections (77% of girls and 74% of boys). Less common infections included Ascaris lumbricoides, Trichurius trichiura, and Strongyloides stercoralis with only 15% of children positive for multiple‐species infections. After adjusting for sex and age, no statistically significant associations were observed between helminth infections and the frequency of reported illness or anthropometric measures of nutritional status. These data demonstrate the difficulty of assessing nutritional impacts of endemic infections. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.
Effects of antiepileptic drugs on lipids, homocysteine, and C‐reactive protein
Authors: Mintzer Scott , Skidmore Christopher T. , Abidin Caitlin J. , Morales Megan C. , Chervoneva Inna , Capuzzi David M. , Sperling Michael R.
Published: April 2009

Objective

The widely prescribed anticonvulsants phenytoin and carbamazepine are potent inducers of cytochrome P450 enzymes, which are involved in cholesterol synthesis. We sought to determine whether these drugs have an effect on cholesterol and other serological markers of vascular risk.

Methods

We recruited 34 epilepsy patients taking carbamazepine or phenytoin in monotherapy whose physicians had elected to change treatment to one of the noninducing anticonvulsants lamotrigine or levetiracetam. Fasting blood samples were obtained both before and 6 weeks after the switch to measure serum lipid fractions, lipoprotein(a), C‐reactive protein, and homocysteine. A comparator group of 16 healthy subjects underwent the same serial studies.

Results

In the epilepsy patients, switch from either phenytoin or carbamazepine produced significant declines in total cholesterol (−24.8mg/dl), atherogenic (non–high‐density lipoprotein) cholesterol (−19.9mg/dl), triglycerides (−47.1mg/dl) (all p < 0.0001), and C‐reactive protein (−31.4%; p = 0.027). Patients who stopped taking carbamazepine also had a 31.2% decline in lipoprotein(a) level (p = 0.0004), whereas those taken off phenytoin had a decrease in homocysteine level (−1.7μmol/L; p = 0.005). All of these changes were significant when compared with those seen in healthy subjects (p < 0.05). Results were similar whether patients were switched to lamotrigine or levetiracetam.

Interpretation

Switching epilepsy patients from the enzyme‐inducers carbamazepine or phenytoin to the noninducing drugs levetiracetam or lamotrigine produces rapid and clinically significant amelioration in several serological markers of vascular risk. These findings suggest that phenytoin and carbamazepine may substantially increase the risk for cardiovascular and cerebrovascular disease. Ann Neurol 2009;65:448–456
Ein Bis(silaselenon) mit zwei donorstabilisierten SiSe‐Bindungen, erhalten durch eine unerwartet stereokonvergente Hydrolyse eines Diselenadisiletans
Authors: Mitra Amitabha , Wojcik Joseph P. , Lecoanet Daniel , Müller Thomas , West Robert
Published: April 2009

Hydrolyse mit Wasser überführt das durch Umsetzung von racemischem Silylen 1 mit elementarem Selen gebildete Diselenadisiletan 2 in das erste Bis(silaselenon) (3; siehe Struktur; grau C, weiß H, blau N, rot O, violett Se, grün Si; d(SiSe)=215 pm). Diese Reaktion verläuft stereokonvergent: Aus der Mischung der rac‐ und meso‐Isomere von 2 wird nur racemisches 3 erhalten.

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Toroidal Micelles of Uniform Size from Diblock Copolymers
Authors: Huang Haiying , Chung Bonghoon , Jung Jueun , Park Hae‐Woong , Chang Taihyun
Published: April 2009

Einheitliche Nanoringe: Stabile toroidale Micellen mit sehr einheitlicher Form und Größe bilden sich spontan aus einem selektiven THF/Ethanol‐Lösungsmittelgemisch (siehe 3D‐AFM‐Bild). Die Donut‐förmigen Micellen können als Template für das Wachsen von Goldnanopartikeln dienen, die sich entlang der Ringoberfläche bilden.

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Umsetzung von Kohlendioxid mit Allenen zu β,γ‐ungesättigten Carbonsäuren
Authors: North Michael
Published: April 2009

Ungeahnte Reaktivität: Trotz seiner vermeintlichen thermodynamischen und kinetischen Inertheit ist Kohlendioxid eine nützliche Ausgangsverbindung für chemische Synthesen, wie die Addition an Allene unter milden reduktiven Bedingungen in Gegenwart eines Palladium‐Pinzettenkomplexes verdeutlicht (siehe Schema). Diese Umsetzung wird in Zusammenhang mit den Bedingungen für CO2‐Fixierung diskutiert. DMF=N,N‐Dimethylformamid, Tf=Trifluormethansulfonyl.

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9‐Boraanthracene Derivatives Stabilized by N‐Heterocyclic Carbenes
Authors: Wood Thomas K. , Piers Warren E. , Keay Brian A. , Parvez Masood
Published: April 2009

2009: Ende der Boraanthracen‐Odyssee: Allgemeine Reaktionswege führen zu Boraanthracen‐Derivaten, die lange postuliert, aber noch nicht beobachtet wurden. Strukturen, photophysikalische Eigenschaften und die bemerkenswerte Reaktionsfähigkeit der Produkte mit Sauerstoff werden beschrieben.

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Titelbild: Nanoscale Chemical Imaging of the Reduction Behavior of a Single Catalyst Particle (Angew. Chem. 20/2009)
Authors: de Smit Emiel , Swart Ingmar , Creemer J. Fredrik , Karunakaran Chithra , Bertwistle Drew , Zandbergen Henny W. , de Groot Frank M. F. , Weckhuysen Bert M.
Published: April 2009

Eisenkatalysatoren wandeln in der Fischer‐Tropsch‐Synthese aus Kohle oder Biomasse gewonnenes Synthesegas (CO/H2) in flüssige Treibstoffe um. In ihrer Zuschrift auf S. 3686 ff. untersuchen B. M. Weckhuysen, F. M. F. de Groot und Mitarbeiter das unterschiedliche Verhalten von Katalysatorvorstufen bei der Vorbehandlung mit H2 auf der Nanometerskala und auf der Ebene des makroskopischen Katalysators. Ihre Beobachtungen helfen, die Funktionsweise des aktivierten Katalysators zu verstehen.

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A Convenient Method for the Synthesis of α‐Ethynylphospholes and Modulation of Their π‐Conjugated Systems
Authors: Matano Yoshihiro , Nakashima Makoto , Imahori Hiroshi
Published: April 2009

Mind the (narrow) gap: α‐Ethynylphospholes generated in situ from the corresponding silyl‐capped precursors were converted into a series of α‐(arylethynyl) phospholes bearing functional substituents as well as an α,α′‐linked terphosphole (see scheme). The terphosphole has a narrow HOMO–LUMO gap owing to efficient π conjugation over the three phosphole rings.

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9‐Boraanthracene Derivatives Stabilized by N‐Heterocyclic Carbenes
Authors: Wood Thomas K. , Piers Warren E. , Keay Brian A. , Parvez Masood
Published: April 2009

2009: A boraanthracene odyssey: General routes to boraanthracene derivatives—long proposed, but never observed—are disclosed, along with the structural and photophysical properties of these compounds and their remarkable reactivity towards oxygen.

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Synthesis and characterization of chitosan‐g‐methacrylic acid and studies of its additional physicochemical properties, such as swelling, metal‐ion sorption, and flocculation behavior
Authors: Mishra Dinesh Kumar , Tripathy Jasaswini , Srivastava Abhishek , Pandey Peeyoosh Kant , Behari Kunj
Published: April 2009

The aim of this study was to examine the synthesis of a graft copolymer of chitosan and methacrylic acid (MAA) by free‐radical polymerization with a potassium peroxymonosulfate/cyclohexanone (CY) redox system in an inert atmosphere. The optimum reaction conditions affording maximum grafting ratio (%G), grafting efficiency (%E), add on (%A), and conversion (%C) were determined. The grafting parameters were found to increase with increasing concentration of MAA up to 24 × 10−2 mol/dm3, but thereafter, these parameters decreased. With increasing concentration of peroxymonosulfate from 0.6 × 10−2 to 1.2 × 10−2 mol/dm3, %G, %A, and %E increased continuously. All of these grafting parameters increased with increasing concentration of CY up to 1.2 × 10−2 mol/dm3, but beyond this concentration, the grafting parameters decreased. With various concentrations of chitosan from 0.6 to 1.4 g/dm3, the maximum %G, %A, and %E were obtained at 1.4 g/dm3. %G, %A, and %C decreased continuously with various concentrations of hydrogen ions from 2 × 10−3 to 6 × 10−3 mol/dm3. The grafting parameters increased with increasing temperature up to 35°C, but thereafter, these parameters decreased. With increasing time period of reaction from 60 to 180 min, %G, %A, and %E increased up to 120 min, but thereafter, these parameters decreased. The graft copolymer was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study of the physical aging of the epoxy system BADGE n = 0/m‐XDA/CaCO3
Authors: Fraga F. , López M. , Soto Tellini V. H. , Rodríguez‐Núñez E. , Martínez‐Ageitos J. M. , Miragaya J.
Published: April 2009

The physical aging of the epoxy network consisting of a diglycidyl ether of bisphenol A (BADGE n = 0), m‐xylylenediamine (m‐XDA), and calcium carbonate was studied by differential scanning calorimetry. The glass transition temperature and the variation of the specific heat capacities were calculated using the method based on the intersection of both enthalpy–temperature lines for glassy and liquid states. The apparent activation energy was calculated using a single method that involved separate temperature and excess enthalpy dependency. All calorimetric data were compared with those obtained for the epoxy network without filled calcium carbonate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A smart hollow filament with thermal sensitive internal diameter
Authors: Meng Qinghao , Liu Jinlian , Shen Liming , Hu Yang , Han Jianping
Published: April 2009

In this work, a thermoplastic shape memory polyurethane was prepared via melt polymerization and a corresponding shape memory hollow fiber was fabricated via melt spinning. The fiber mechanical properties, especially shape memory effect, were characterized by static tensile, thermo‐mechanical cyclic tensile testing. The hollow fiber switching temperature was the melting transition temperature of the soft segment phase at about 41°C. The tenacity of the hollow fiber was about 1.14 cN/dtex, and breaking elongation was 682%. The shape fixity ratio was above 87% and the recovery ratio was above 89%. The internal diameter of the hollow fiber could be noticeably changed and the deformed fiber cross‐section could be well fixed. Once heated above the soft segment phase melting transition temperature, the hollow fiber internal hole recovered to its original diameter. The results from differential scanning calorimetry, X‐ray diffraction, and dynamic mechanical analysis were used to illustrate the mechanism governing the mechanical properties and shape memory effect especially. Due to the changes of the hollow fiber and the internal diameter affect of the physical properties of the prepared products, this fiber may be used in smart textiles for thermal management, or as stuffing of pillows and mattresses, which can adjust to body contours. Furthermore, the findings suggest that this kind of hollow fiber with thermal sensitive internal diameter could be used in smart filtration, drug‐controlled release, and liquid transportationin vivo. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Hydroxypropylation of cellulose isolated from bamboo (Dendrocalamus strictus) with respect to hydroxypropoxyl content and rheological behavior of the hydroxypropyl cellulose
Authors: Sharma Ritu , Varshney V. K. , Chauhan Ghanshyam S. , Naithani Sanjay , Soni P. L.
Published: April 2009

Bamboo, a lignocellulosic material, is a renewable source of interest as feedstock for production of cellulose derivatives by chemical functionalization. Optimization of hydroxypropylation of cellulosic material (average DP 816), isolated from bamboo (Dendrocalamus strictus) was, therefore, performed with respect to maximum percent hydroxylpropoxyl (% HP) contents under varying reaction conditions and studying their effect on the % HP. The optimized reaction conditions were aqueous NaOH concentration 22%, propylene oxide concentration 17.4 mol/AGU, temperature 50°C, duration of hydroxypropylation 4 h to yield hydroxypropyl cellulose of % HP 65.89. The ηapp of 1 and 2% solutions of the optimized product showed it to be non‐Newtonian pseudoplastic. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Soy‐based polyols from oxirane ring opening by alcoholysis reaction
Authors: Lozada Zuleica , Suppes Galen J. , Tu Yuan‐Chan , Hsieh Fu‐Hung
Published: April 2009

A screening study was conducted to identify a catalyst that promotes epoxy ring opening of full epoxidized soybean oil (ESBO) avoiding side reactions at low concentration and temperature. Six catalysts different catalyst: formic acid, phosphoric acid, POLYCAT® 5, p‐toluenesulfonic acid monohydrate, POLYCAT® SA‐1, and DABCO® BL17 were evaluated in terms of acid number, oxirane oxygen content, and color analyses. p‐Toluenesulfonic acid shows a particular behavior that promotes the reaction resulting in a maximum oxirane oxygen content reduction; low acid number and color index compare to the others catalyst. To create an alkoxy hydroxy ESBO molecule, ESBO was combined with methanol and ethylene glycol using 0.5% by wt of p‐toluenesulfonic acid at 130, 150, and 170°C for different reaction times. Optimal conditions for oxirane ring opening by alcoholysis reaction were determined varying temperatures and reaction times. FTIR spectrum confirmed the emergence of hydroxyl groups in the alkoxy hydroxy ESBO polyol sample. The polyol sample G was characterized in terms of its hydroxyl number and its potential of replacing up from 50–100% of the petroleum‐based polyol in waterborne rigid polyurethane foam application. All polyurethanes foams were evaluated to determine their thermal conductivity, density, and compressive strength properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dynamic responses of irregular fibers under axial tension
Authors: Yan Wenyi , Li Zhi , Wang Xungai , Wang Lijing
Published: April 2009

A numerical study on the dynamic responses of irregular fibers under axial tension is presented in this article. The irregularity was represented by a sinusoidal shape profile along the fiber axis. The finite element method was used in the simulations and the maximum first principal stress due to the dynamic pulling has been examined. Our numerical results indicate that the first principal stress mainly varies along the longitudinal direction. Its change in radial direction is negligibly small. The maximum first principal stress in an irregular fiber always appears in the narrowest crosssection, which is the weakest link of the fiber. The maximum first principal stress is very sensitive to the change in the irregular amplitude. The stress value increases dramatically with the increase in the amplitude of irregularity. The frequency of irregularity has a limited effect on the maximum first principal stress. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polymer dynamics in rubbery epoxy networks/polyhedral oligomeric silsesquioxanes nanocomposites
Authors: Kourkoutsaki Th. , Logakis E. , Kroutilova I. , Matejka L. , Nedbal J. , Pissis P.
Published: April 2009

Dielectric techniques, including thermally stimulated depolarization currents (TSDC, −150 to 30°C) and, mainly, broadband dielectric relaxation spectroscopy (DRS, 10−2 – 106 Hz, −150 to 150°C) were employed, next to differential scanning calorimetry (DSC), to investigate molecular dynamics in rubbery epoxy networks prepared from diglycidyl ether of Bisphenol A (DGEBA) and poly(oxypropylene)diamine (Jeffamine D2000, molecular mass 2000) and modified with polyhedral oligomeric silsesquioxanes (POSS) units covalently bound to the chains as dangling blocks. Four relaxations were detected and analyzed: in the order of increasing temperature at constant frequency, two local, secondary γ and β relaxations in the glassy state, the segmental α relaxation associated with the glass transition and the normal mode relaxation, related with the presence of a dipole moment component along the Jeffamine chain contour. Measurements on pure Jeffamine D2000 helped to clarify the molecular origin of the relaxations observed. A significant reduction of the magnitude and a slight acceleration of the α and of the normal mode relaxations were observed in the modified networks. These results suggest that a fraction of polymer is immobilized, probably at interfaces with POSS, due to constraints imposed by the covalently bound rigid nanoparticles, whereas the rest exhibits a slightly faster dynamics due to increaseof free volume resulting from loosened molecular packing of the chains (plasticization by the bulky POSS units).The increase of free volume is rationalized by density measurements. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Imidazolium‐organic solvent–alkali metal salt mixtures as nonflammable electrolytes incorporated into PVDF–PEG polymer electrolyte
Authors: Wang Yun‐Pu , Gao Xiang‐Hu , Chen Jiu‐Cun , Li Zhi‐Wen , Li Cheng‐Lin , Zhang Shou‐Cun
Published: April 2009

A mixture of flammable organic solvent, alkali metal salt, and nonflammable room temperature ionic liquid has been used as a new type of electrolyte. A novel microporous polymer electrolyte based on poly(vinylidene fluoride), i.e., PVDF, and poly(ethylene glycol), i.e., PEG, was prepared by a simple phase‐inversion technique. The mixed electrolyte was observed to be nonflammable at ionic liquid contents of 60 vol % or greater. The viscosity (range, 0.98–30.5 mPa s) and conductivity (range, 9.9 to 22.25 mS cm−1) of the mixed electrolyte were discussed. The porosity, solution uptake, and conductivity mechanism of polymer membranes also were discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Fluconazole release through semi‐interpenetrating polymer network hydrogels based on chitosan, acrylic acid, and citraconic acid
Authors: Pulat Mehlika , Asıl Dilek
Published: April 2009

Semi‐interpenetrating polymer network hydrogels with different compositions of chitosan (Cs), acrylic acid, and citraconic acid were synthesized via free‐radical polymerization with ethylene glycol dimethacrylate as a crosslinker. The variations of the swelling percentages of the hydrogels with time, temperature, and pH were determined, and Cs–poly(acrylic acid) (PAA) hydrogels were found to be most swollen at pH 7.4 and 37°C. Scanning electron micrographs of Cs–PAA and Cs–P(AA‐co‐CA)‐1 (Cs‐poly(acrylicacid‐co‐citraconir acid)−1) were taken to observe the morphological differences in the hydrogels. Although the less swollen hydrogel, Cs–P(AA‐co‐CA)‐1, had a sponge‐type structure, the most swollen hydrogel, Cs–PAA, displayed a uniform porous appearance. Fluconazole was entrapped in Cs–P(AA‐co‐CA)‐1 and Cs–PAA hydrogels, and the release was investigated at pH 4.0 and 37°C. The kinetic release parameters of the hydrogels (the gel characteristic constant and the swelling exponent) were calculated, and non‐Fickian diffusion was established for Cs–PAA, which released fluconazole much more slowly than the Cs–P(AA‐co‐CA)‐1 hydrogel. A therapeutic range was reached at close to 1 h for both hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Electrospun polylactide/silk fibroin–gelatin composite tubular scaffolds for small‐diameter tissue engineering blood vessels
Authors: Wang Shudong , Zhang Youzhu , Yin Guibo , Wang Hongwei , Dong Zhihui
Published: April 2009

Many synthetic scaffolds have been used as vascular substitutes for clinical use. However, many of these scaffolds may not show suitable properties when they are exposed to physiologic vascular environments, and they may fail eventually because of some unexpected conditions. Electrospinning technology offers the potential for controlling the composition, structure, and mechanical properties of scaffolds. In this study, a tubular scaffold (inner diameter = 4.5 mm) composed of a polylactide (PLA) fiber outside layer and a silk fibroin (SF)–gelatin fiber inner layer (PLA/SF–gelatin) was fabricated by electrospinning. The morphological, biomechanical, and biological properties of the composite scaffold were examined. The PLA/SF–gelatin composite tubular scaffold possessed a porous structure; the porosity of the scaffold reached 82 ± 2%. The composite scaffold achieved the appropriate breaking strength (1.28 ± 0.21 MPa) and adequate pliability (elasticity up to 41.11 ± 2.17% strain) and possessed a fine suture retention strength (1.07 ± 0.07 N). The burst pressure of the composite scaffold was 111.4 ± 2.6 kPa, which was much higher than the native vessels. A mitochondrial metabolic assay and scanning electron microscopy observations indicated that both 3T3 mouse fibroblasts and human umbilical vein endothelial cells grew and proliferated well on the composite scaffold in vitro after they were cultured for some days. The PLA/SF–gelatin composite tubular scaffolds presented appropriate characteristics to be considered as candidate scaffolds for blood vessel tissue engineering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of process parameters on properties of wet‐spun poly(L,D‐lactide) copolymer multifilament fibers
Authors: Rissanen Marja , Puolakka Arja , Hukka Terttu , Ellä Ville , Nousiainen Pertti , Kellomäki Minna
Published: April 2009

Poly(L,D‐lactide) [P(L,D)LA], LL/D ratio 96/4, and poly(L,DL‐lactide) [P(L,DL)LA], L/DL ratio 70/30, multifilament fibers were prepared by wet‐spinning and the effects of the spin draw ratio and the coagulant on the morphological, thermal, and mechanical properties of the filaments were studied. The hydrolytic degradation of filaments was studied in vitro. The filament diameter and the mechanical properties of filaments were highly dependent on the spin draw ratio, whereas the coagulant had no or minor effect. The filament diameters were in the range of 11–36 μm and the maximum tenacity of 150 MPa was obtained at the spin draw ratio of 7.0 for both copolymers. The copolymer had the main importance on the crystallinity of filaments, but it was also affected by the duration of the coagulation process. The crystallinities of P(L,D)LA 96/4 filaments were in the range of 5–16%, whereas P(L,DL)LA 70/30 filaments were totally amorphous. The degree of crystallinity had effect on the hydrolytic degradation of filaments. The tenacity loss of P(L,D)LA 96/4 filaments was about 10% and that of P(L,DL)LA 70/30 filaments was as high as 50% after 24 weeks in vitro. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Functional Correlates of Fiber Architecture of the Lateral Caudal Musculature in Prehensile and Nonprehensile Tails of the Platyrrhini (Primates) and Procyonidae (Carnivora)
Authors: Organ Jason M. , Teaford Mark F. , Taylor Andrea B.
Published: April 2009

Prehensile‐tailed platyrrhines (atelines and Cebus) and procyonids (Potos) display bony tail features that have been functionally and adaptively linked to their prehensile behaviors, particularly the need to resist relatively greater bending and torsional stresses associated with supporting their body weight during suspensory postures. We compared fiber architecture of the mm. intertransversarii caudae (ITC), the prime tail lateral flexors/rotators, in 40 individuals distributed across 8 platyrrhine and 2 procyonid genera, divided into one of two groups: prehensile or nonprehensile. We tested the hypothesis that prehensile‐tailed taxa exhibit relatively greater physiologic cross‐sectional areas (PCSAs) to maintain tail suspensory postures for extended periods. As an architectural trade‐off of maximizing force, we also predicted prehensile‐tailed taxa would exhibit relatively shorter, more pinnate fibers, and a lower mass to tetanic tension ratio (Mass/PO). Prehensile‐tailed taxa have relatively higher PCSAs in all tail regions, indicating their capacity to generate relatively greater maximum muscle forces compared to nonprehensile‐tailed taxa. Contrary to our predictions, there are no group differences in pinnation angles, fiber lengths or M/PO ratios. Therefore, the relatively greater prehensile PCSAs are driven largely by relative increase in muscle mass. These findings suggest that relatively greater ITC PCSAs can be functionally linked to the need for prehensile‐tailed taxa to suspend and support their body weight during arboreal behaviors. Moreover, maximizing ITC force production may not come at the expense of muscle excursion/contraction velocity. One advantage of this architectural configuration is it facilitates suspension of the body while simultaneously maximizing tail contact with the substrate. Anat Rec, 292:827–841, 2009. © 2009 Wiley‐Liss, Inc.
Cover Picture: Monitoring the Formation of Coordination Complexes Using Electrospray Mass Spectrometry (Chem. Asian J. 5/2009)
Authors: Mathieson Jennifer S. , Cooper Geoffrey J. T. , Pickering Alexandra L. , Keller Marco , Long De‐Liang , Newton Graham N. , Cronin Leroy
Published: April 2009

The rigid Schiff‐base ligand cis,trans‐1,3,5‐tris(pyridine‐2‐carboxaldimino) cyclohexane is synthesized, and its complexation to copper(II) salts at a range of stoichiometries is investigated. L. Cronin et al. show that the complexation reaction leads to the crystallization of transition‐metal complexes with nuclearities of 1, 2, and 4, and the formation of the complexes can be followed stepwise, in real time, using electrospray mass spectrometry. For more information, see their Full Paper on page 681 ff.

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Industrial perspectives of AFM control
Authors: Su Chanmin
Published: April 2009

The controllers delivered by atomic force microscope (AFM) manufacturers to AFM users are several decades behind various advanced control technology. This paper is trying to analyze factors that created this gap to reach certain specifications, either quantitatively or qualitatively, of an ideal controller viewing from AFM industries. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Identification, control and hysteresis compensation of a 3 DOF metrological AFM
Authors: Merry Roel , Uyanik Mustafa , van de Molengraft René , Koops Richard , van Veghel Marijn , Steinbuch Maarten
Published: April 2009

Atomic Force Microscopes (AFMs) are widely used for the investigation of samples at the nanometer scale. The metrological AFM used in this work uses a 3 degrees‐of‐freedom (DOFs) stage, driven by piezo‐stack actuators, for sample manipulation in combination with a fixed cantilever. The piezo‐stack actuators suffer from hysteresis, which acts as a nonlinear disturbance on the system and/or can change the system dynamics. The contributions of this paper are the application of feedback control to all 3 DOFs of the metrological AFM and the design and application of a hysteresis feedforward for the asymmetric hysteresis present in the system. The amount of coupling between the DOFs is assessed by a non‐parametric multiple‐input‐multiple‐output (MIMO) identification. Since the dynamics appear to be decoupled in the frequency range of interest, feedback controllers are designed for each DOF separately. For the modeling of the asymmetric hysteresis an extended Coleman‐Hodgdon model is proposed. This model is used for feedforward compensation of the hysteresis. The combination of feedback control for all DOFs and the asymmetric hysteresis feedforward enables the AFM to track scanning profiles within the sensor bound of 5 nm. Real‐time imaging of the sample is possible with an accuracy of 2 nm. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
High‐speed serial‐kinematic SPM scanner: design and drive considerations
Authors: Leang Kam K. , Fleming Andrew J.
Published: April 2009

This paper describes the design of a flexure‐guided, two‐axis nanopositioner (scanner) driven by piezoelectric stack actuators. The scanner is specifically designed for high‐speed scanning probe microscopy (SPM) applications, such as atomic force microscopy (AFM). A high‐speed AFM scanner is an essential component for acquiring high‐resolution, three‐dimensional, time‐lapse images of fast processes such as the rapid movement of cells and the diffusion of DNA molecules. A two‐axis SPM scanner is proposed, where the slow and fast scanning axes are serially connected and flexure guided to minimize runout. The scanner's achievable scan range is approximately 10µm × 10µm. Finite element analysis is utilized to optimize the mechanical resonance frequencies of the scanner. Experimental results show a first major resonance in the slow and fast axis at 1.5 and 29 kHz, respectively. This paper also discusses the various tradeoffs between speed, range, electrical requirements, and scan trajectory design for high‐speed nanopositioning. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Creep and hysteresis compensation for nanomanipulation using atomic force microscope
Authors: Yang Qinmin , Jagannathan S.
Published: April 2009

In this paper, a novel scheme is presented to simultaneously compensate the inherent creep and hysteresis nonlinearities of a piezoelectric actuator while positioning the Atomic Force Microscope (AFM) tip. In order to mitigate these nonlinearities, creep and hysteresis phenomenon are first modeled separately by using the classical Prandtl‐Ishlinskii (PI) operator. Then, a linear time‐invariant (LTI) representation is obtained to identify the creep uncertainty and subsequently an adaptive control scheme is devised for the piezoelectric actuator to track a desired path in the presence of creep. An additional dynamic inversion loop is utilized by using an online approximator to offset the hysteresis effects without the need of identifying the parameters within the hysteresis model. Rigorous performance analysis is conducted using standard Lyapunov stability approach along with simulation results. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A new potential field method for mobile robot path planning in the dynamic environments
Authors: Yin Lu , Yin Yixin , Lin Cheng‐Jian
Published: April 2009

A new potential field method for mobile robot path planning is proposed in this paper. At present, most potential field methods are designed to be applied in the stationary environment, and several improved potential functions have brought in the velocity factors in the dynamic circumstances. Based on the consideration that the moving trend of the robot in the dynamic environments is also necessary to produce more reasonable path, this paper defines new attractive potential function with respect to the relative position, velocity, and acceleration between the robot and the goal, as well as the repulsive potential function with respect to the relative positions, velocities, and accelerations between the robot and the obstacles. The virtual forces are calculated to make the robot plan its motion, not only with right positions, but also with suitable velocities. Furthermore, the robot will keep a similar moving trend with the goal and contrary trends with the obstacles. Finally, some methodic simulations are carried out to validate and demonstrate the effectiveness of the new potential field method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
On stability and stabilizability of positive delay systems
Authors: Wu Ligang , Lam James , Shu Zhan , Du Baozhu
Published: April 2009

The stabilization problem with positivity is investigated in this note for discrete‐time linear systems with time delay. A delay‐independent necessary and sufficient condition is proposed in terms of linear matrix inequalities (LMIs) for the existence of desired controllers that guarantee the closed‐loop system to be asymptotically stable and positive. In addition, the obtained result is further extended to more general case when the system matrices contain uncertain parameters, where a sufficient condition is obtained. The frequently used polytopic parameter uncertainty is taken into consideration. Since the conditions obtained are expressed as LMIs, which can be easily verified by using standard numerical software. A numerical example is provided to illustrate the proposed results. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Shrinkage drift parameter estimation for multi‐factor Ornstein–Uhlenbeck processes
Authors: Nkurunziza Sévérien , Ahmed S. Ejaz
Published: April 2009

We consider some inference problems concerning the drift parameters of multi‐factors Vasicek model (or multivariate Ornstein–Uhlebeck process). For example, in modeling for interest rates, the Vasicek model asserts that the term structure of interest rate is not just a single process, but rather a superposition of several analogous processes. This motivates us to develop an improved estimation theory for the drift parameters when homogeneity of several parameters may hold. However, the information regarding the equality of these parameters may be imprecise. In this context, we consider Stein‐rule (or shrinkage) estimators that allow us to improve on the performance of the classical maximum likelihood estimator (MLE). Under an asymptotic distributional quadratic risk criterion, their relative dominance is explored and assessed. We illustrate the suggested methods by analyzing interbank interest rates of three European countries. Further, a simulation study illustrates the behavior of the suggested method for observation periods of small and moderate lengths of time. Our analytical and simulation results demonstrate that shrinkage estimators (SEs) provide excellent estimation accuracy and outperform the MLE uniformly. An over‐ridding theme of this paper is that the SEs provide powerful extensions of their classical counterparts. Copyright © 2009 John Wiley & Sons, Ltd.
Pension funding problem with regime‐switching geometric Brownian motion assets and liabilities
Authors: Chen Ping , Yang Hailiang
Published: April 2009

This paper extends the pension funding model in (N. Am. Actuarial J.2003;7:37–51) to a regime‐switching case. The market mode is modeled by a continuous‐time stationary Markov chain. The asset value process and liability value process are modeled by Markov‐modulated geometric Brownian motions. We consider a pension funding plan in which the asset value is to be within a band that is proportional to the liability value. The pension plan sponsor is asked to provide sufficient funds to guarantee the asset value stays above the lower barrier of the band. The amount by which the asset value exceeds the upper barrier will be paid back to the sponsor. By applying differential equation approach, this paper calculates the expected present value of the payments to be made by the sponsor as well as that of the refunds to the sponsor. In addition, we study the effects of different barriers and regime switching on the results using some numerical examples. The optimal dividend problem is studied in our examples as an application of our theory. Copyright © 2009 John Wiley & Sons, Ltd.
Solvent‐dependent conformation of amylose tris(phenylcarbamate) as deduced from scattering and viscosity data
Authors: Fujii Taichi , Terao Ken , Tsuda Maiko , Kitamura Shinichi , Norisuye Takashi
Published: April 2009

The z‐average mean‐square radius of gyration 〈S2〉z, the particle scattering function P(k), the second virial coefficient, and the intrinsic viscosity [η] have been determined for amylose tris(phenylcarbamate) (ATPC) in methyl acetate (MEA) at 25°C, in ethyl acetate (EA) at 33°C, and in 4‐methyl‐2‐pentanone (MIBK) at 25°C by light and small‐angle X‐ray scattering and viscometry as functions of the weight‐average molecular weight in a range from 2 × 104 to 3 × 106. The first two solvents attain the theta state, whereas the last one is a good solvent for the amylose derivative. Analysis of the 〈S2〉z, P(k), and [η] data based on the wormlike chain yields h (the contour length or helix pitch per repeating unit) = 0.37 ± 0.02 and λ−1 (the Kuhn segment length) = 15 ± 2 nm in MEA, h = 0.39 ± 0.02 and λ−1 = 17 ± 2 nm in EA, and h = 0.42 ± 0.02 nm and λ−1 = 24 ± 2 nm in MIBK. These h values, comparable with the helix pitches (0.37–0.40 nm) per residue of amylose triesters in the crystalline state, are somewhat larger than the previously determined h of 0.33 ± 0.02 nm for ATPC in 1,4‐dioxane and 2‐ethoxyethanol, in which intramolecular hydrogen bonds are formed between the CO and NH groups of the neighbor repeating units. The slightly extended helices of ATPC in the ketone and ester solvents are most likely due to the replacement of those hydrogen bonds by intermolecular hydrogen bonds between the NH groups of the polymer and the carbonyl groups of the solvent. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 729–736, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
A spectroscopic investigation into the interactions of 3′‐O‐carboxy esters of thymidine with bovine serum albumin
Authors: Ghosh Kalyan Sundar , Sen Shiladitya , Sahoo Bijaya Ketan , Dasgupta Swagata
Published: April 2009

Binding studies of 3′‐O‐carboxy esters of thymidine, reported inhibitors of ribonucleases, with bovine serum albumin (BSA) have been explored in this report. Fluorescence spectroscopy in combination with Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy have been used to determine the nature and mode of binding. The binding and quenching parameters were determined from tryptophan fluorescence quenching by Scatchard plots and modified Stern–Volmer plots. The association constants are of the order of 104M−1for both the ligands. Thermodynamic parameters suggest that apart from an initial hydrophobic association, hydrogen bonding and van der Waals interactions play a decisive role during protein‐ligand complex formation. Minor changes were observed in the secondary structures of human serum albumin (HSA) as revealed by FTIR and CD. Docking studies suggest that the ligands are close to Trp 213, which causes fluorescence quenching. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 737–744, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Cultural consequences of miscarriages of justice
Authors: Cole Simon A.
Published: April 2009

Social science scholarship has tended to focus more on the causes than the consequences of miscarriages of justice. Within the literature on consequences, the overwhelming emphasis has been on individual consequences: psychological and material impacts on the wrongly convicted individual and, in some cases, other indirectly impacted individuals such as family members of the wrongly convicted and victims of the true perpetrator's future crimes. Some attention has been devoted to social harms, the impact of miscarriages of justice on the broader society within which they are situated, such as the undermining of the legitimacy of the criminal justice system. This paper focuses on what are called here cultural consequences of miscarriages of justice: the way in which some high‐profile miscarriages of justice can shape the public's beliefs about some of the most basic “facts” about crime, such as the nature, prevalence, or even existence of certain categories of crime and the types of individual who tend to perpetrate particular types of crime. In this way, the paper argues, miscarriages of justice may have hitherto underexplored consequences: reshaping, based on false premises, the public's belief about the very nature of crime itself. This paper discusses three cases studies of miscarriages of justice that for varying periods of time created widespread false beliefs about the nature of crime in large segments of the public. The paper concludes by noting that the “righting” of these false beliefs was in most cases fortuitous. This suggests that unexposed miscarriages of justice may still be shaping popular beliefs about the nature of crime, and aspects of the public's current conception of crime may yet be based on false premises. Copyright © 2009 John Wiley & Sons, Ltd.