bluuebunny/crossref_metadata_2025 huggingface dataset:
The Connection Between Entropy and the Absorption Spectra of Schwarzschild Black Holes for Light and Massless Scalar Fields
Authors: Mendoza Sergio , Hernandez Xavier , Rendón Pablo , Lopez-Monsalvo C. , Velasco-Segura Roberto
Published: January 2009

We present heuristic arguments suggesting that if EM waves with wavelengths somewhat larger than the Schwarzschild radius of a black hole were fully absorbed by it, the second law of thermodynamics would be violated, under the Bekenstein interpretation of the area of a black hole as a measure of its entropy. Thus, entropy considerations make the well known fact that large wavelengths are only marginally absorbed by black holes, a natural consequence of thermodynamics. We also study numerically the ingoing radial propagation of a scalar field wave in a Schwarzschild metric, relaxing the standard assumption which leads to the eikonal equation, that the wave has zero spatial extent. We find that if these waves have wavelengths larger that the Schwarzschild radius, they are very substantially reflected, fully to numerical accuracy. Interestingly, this critical wavelength approximately coincides with the one derived from entropy considerations of the EM field, and is consistent with well known limit results of scattering in the Schwarzschild metric. The propagation speed is also calculated and seen to differ from the value c, for wavelengths larger than Rs, in the vicinity of Rs. As in all classical wave phenomena, whenever the wavelength is larger or comparable to the physical size of elements in the system, in this case changes in the metric, the zero extent ’particle’ description fails, and the wave nature becomes apparent.
Optimization and Comparison of Five Methods for Extraction of Coniferyl Ferulate from Angelica sinensis
Authors: Xie Jing-Jing , Lu Jia , Qian Zheng-Ming , Yu Yue , Duan Jin-Ao , Li Shao-Ping
Published: January 2009

Coniferyl ferulate, which is noted for its multiple pharmacological activities and chemical instability, is abundant in Angelica sinensis. In this paper, five methods, namely sonication extraction (SE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), hydrodistillation (HD) and decoction (DC) for extraction of coniferyl ferulate, as well as ferulic acid, Z/E-ligustilide and Z/E-butylidenephthalide, from A. sinensis were optimized and compared. The results showed that the order of extraction efficiency was: PLE»SE>SFE>>HD, DC. The compositions of the SE, PLE and SFE extracts, which had a high ratio of coniferyl ferulate, were very similar, while no coniferyl ferulate was obtained by HD and DC, though they had high selectivity for the extraction of ligustilide and ferulic acid, respectively. It was noteworthy that the content of ligustilide and coniferyl ferulate was not detectable in the decoction, the commonly used oral administration form of Traditional Chinese Medicines in clinical practice.
A Two-Dimensional Micro Scanner Integrated with a Piezoelectric Actuator and Piezoresistors
Authors: Zhang Chi , Zhang Gaofei , You Zheng
Published: January 2009

A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26º × 23º. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively.
Use of Reflectance Ratios as a Proxy for Coastal Water Constituent Monitoring in the Pearl River Estuary
Authors: Fang Li-Gang , Chen Shui-Sen , Li Dong , Li Hong-Li
Published: January 2009

Spectra, salinity, total suspended solids (TSS, in mg/L) and colored dissolved organic matter (CDOM, ag(400) at 400 nm) sampled in stations in 44 different locations on December 18, 19 and 21, in 2006 were measured and analyzed. The studied field covered a large variety of optically different waters, the absorption coefficient of CDOM ([ag(400)] in m-1) varied between 0.488 and 1.41 m-1, and the TSS concentrations (mg/L) varied between 7.0 and 241.1 mg/L. In order to detect salinity of the Pearl River Estuary, we analyzed the spectral properties of TSS and CDOM, and the relationships between field water reflectance spectra and water constituents’ concentrations based on the synchronous in-situ and satellite hyper-spectral image analysis. A good correlation was discovered (the positive correlation by linear fit), between in-situ reflectance ratio R680/R527 and TSS concentrations (R2 = 0.65) for the salinity range of 1.74-22.12. However, the result also showed that the absorption coefficient of CDOM was not tightly correlated with reflectance. In addition, we also observed two significant relationships (R2 > 0.77), one between TSS concentrations and surface salinity and the other between the absorption coefficient of CDOM and surface salinity. Finally, we develop a novel method to understand surface salinity distribution of estuarine waters from the calibrated EO-1 Hyperion reflectance data in the Pearl River Estuary, i.e. channels with high salinity and shoals with low salinity. The EO-1 Hyperion derived surface salinity and TSSconcentrations were validated using in-situ data that were collected on December 21, 2006, synchronous with EO-1 Hyperion satellite imagery acquisition. The results showed that the semi-empirical relationships are capable of predicting salinity from EO-1 Hyperion imagery in the Pearl River Estuary (RMSE < 2‰).
Occurrence of ochratoxin A and heavy metals in tissues associated with porcine nephropathy in Serbia
Authors: Milićević D. , Jurić V. , Stefanović S. , Jovanović M. , Petrović Z. , Vuković D.
Published: January 2009

In order to find information on the occurrence of mycotoxic porcine nephropathy in Serbia, during a six month period (2006/2007) samples of blood, kidney and liver from individual animals were collected from healthy slaughtered pigs (n=90) and analysed by HPLC for ochratoxin A (OTA). In addition, the presence of nephrotoxic heavy metals such as cadmium, lead, mercury and arsenic were measured and the kidneys pathohistologically examined. Of the 90 liver samples, 26.6% contained OTA in the range of 0.22-14.5 ng/g. The incidence of OTA in serum and kidney were very similar (30 and 31.1%), but varied between 0.24-220.8 ng/ml and 0.17-52.5 ng/g, respectively. The presence of mercury was confirmed in 33.3% of kidney samples and concentrations ranged between 0.005-0.055 mg/kg, while cadmium was found less frequently (27.7% positive samples) but at higher levels (0.05-1.23 mg/kg). The presence of arsenic was found in only one sample, while lead was not detected in any sample. Histopathological examination of kidneys confirmed tubulopathies with oedema and cell vacuolisation. In addition, haemorrhages and necrosis of proximal kidney tubules' cells were found. These findings indicate that it is likely that most of the kidney injury is related to OTA and other nephrotoxic compounds which enhance the toxicity of OTA.
Natural maize phytochemicals for control of maize mycoflora and aflatoxigenic fungi
Authors: Nesci A. , Marín S. , Etcheverry M. , Sanchis V.
Published: January 2009

This research was undertaken to evaluate the effects of the natural phytochemicals trans-cinnamic acid (CA) alone
at concentrations of 20 and 25 mM, ferulic acid (FA) at concentration of 30 mM and two mixtures, CA-FA (20+30
mM) and CA-FA (25+30 mM) on natural maize mycoflora, Aspergillus section Flavi population and aflatoxin B1
production. These studies were carried out in maize grain in relation to a water activity of 0.99, 0.97 and 0.94. CA
at 25 mM and the mixture CA-FA (25+30 mM) were the most effective treatments at inhibiting natural maize
mycoflora at all aw assayed after 11 and 35 days of incubation at 25 °C. In general, 20 mM CA caused complete
inhibition of Aspergillus section Flavi population at all aw values tested during all incubation period without an
additional inoculum. 20 mM CA and 25 mM CA showed the major inhibitory effect on aflatoxin B1 accumulation
of control and Aspergillus section Flavi additionally inoculated during all incubation periods. The data showed that
CA and FA could be considered as effective fungitoxicants for natural maize mycoflora and aflatoxigenic fungi in the
aw range 0.99 to 0.94. The information obtained shows promise for controlling aflatoxigenic fungi in stored maize.
Developments in mycotoxin analysis: an update for 2007-2008
Authors: Shephard G. , Berthiller F. , Dorner J. , Krska R. , Lombaert G. , Malone B. , Maragos C. , Sabino M. , Solfrizzo M. , Trucksess M. , van Egmond H. , Whitaker T.
Published: January 2009

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2007 and mid-2008. It covers the major mycotoxins: aflatoxins,Alternariatoxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Some aspects of natural occurrence, particularly if linked to novel aspects of analytical methods, are also included. The review demonstrates the rise of LC-MS methods, the continuing interest in developing alternative and rapid methods and the modification of well-established mycotoxin analytical methods by individual laboratories to meet their own requirements.
Emergencia y configuración del asociacionismo familiar en España
Authors: Ayuso Sánchez Luis
Published: January 2009

Las asociaciones familiares representan fenómenos característicos de las sociedades avanzadas actuales, al combinar tendencias asociativas y comunitarias. En su configuración se reflejan rasgos propios de los nuevos movimientos sociales y las organizaciones del tercer sector, poniéndose el acento en la autonomía de la sociedad civil para organizarse alrededor de la familia. En este trabajo se presenta una aproximación a estos actores en España, aportando diferentes claves teóricas para su interpretación y un análisis cuantitativo y cualitativo sobre su presencia y configuración en nuestro país.
Confianza, incertidumbre y percepción social de las tecnologías avanzadas. Un estudio de caso
Authors: Solá Rosario , Prades Ana , Espluga Josep , Real Marta
Published: January 2009

En este artículo se reflexiona sobre el papel de la confianza en la configuración de las percepciones y respuestas sociales de una población expuesta a una nueva instalación tecnológica, concretamente ante la implantación de un Centro de Investigación sobre la combustión limpia de carbón en un territorio minero del noroeste de España. Para ello, mediante una estrategia metodológica que integra técnicas cuantitativas y cualitativas, se analizan las percepciones ciudadanas en el momento del anuncio de la creación de dicha instalación tecnológica. Los resultados permiten discutir el peso que habitualmente se tiende a otorgar a la confianza en las instituciones gestoras del riesgo en la configuración de las percepciones públicas, así como en la mayor o menor aceptación social de ciertas tecnologías emergentes.
Religious and spiritual issues in medical genetics
Authors: Fanning Joseph B. , Clayton Ellen Wright
Published: January 2009

This article provides an overview of a special issue on the religious and spiritual concerns that arise in the provision of genetic services. It introduces some of the challenges in defining religion and spirituality and provides contexts and summaries for the empirical and normative research that appears in the issue. © 2009 Wiley‐Liss, Inc.
A religious framework as a lens for understanding the intersection of genetics, health, and disease
Authors: Harris Tina M. , Keeley Bethany , Barrientos Samantha , Gronnvoll Marita , Landau Jamie , Groscurth Christopher R. , Shen Lijiang , Cheng Youyou , Cisneros J. David
Published: January 2009

The primary goal of this study was to determine the extent to which religious frameworks inform lay public understandings of genes and disease. Contrary to existing research, there were minimal differences between racial groups. We did, however, observe two patterns in that data that are worthy of discussion. First, because participants were from the south, the finding that participants from both racial groups ascribe to a religious belief system to make sense of their lived experiences is not surprising. Rather, it appears to be reflective of the religious culture that is an integral part of the south and our identity as a nation. A second noteworthy finding is that while a significant number of participants believe that a relationship exists between health status, genes, and religious behaviors, they also recognize that positive health behaviors must also be adopted as a means for staving off disease. In some cases, however, there was a belief that health issues could dissolve or disappear as a result of certain religious behaviors such as prayer. © 2009 Wiley‐Liss, Inc.
The role and impact of personal faith and religion among genetic service providers
Authors: Geller Gail , Micco Ellyn , Silver Rachel J. , Kolodner Ken , Bernhardt Barbara A.
Published: January 2009

This paper describes the impact of genetic service providers' personal faith and religious values on their experiences interacting with colleagues and patients. We surveyed 480 clinical geneticists (MDs), genetic counselors (GCs), and genetic nurses randomly selected from their professional associations, and then interviewed a sample of survey respondents. Outcomes included religiosity, coping with distress through spiritual beliefs, and personal value conflicts (PVCs). Two hundred fourteen providers completed the survey out of an estimated 348 eligible (61% response rate). Importance attributed to regular attendance at religious services ranged from 39% (not at all important) to 27% (very important). Reliance on religion and spiritual beliefs as a source of comfort ranged from 48% (never) to 33% (sometimes or often). Religiosity varied by discipline with 58% of nurses thinking regular attendance at religious services was moderately or very important as compared to 47% of GCs and 30% of MDs (P = 0.006). Ten percent of respondents had difficulty reconciling their own faith with being a genetics professional, 14% felt the need to hide their own faith from their colleagues or patients, 7% thought their professional stance was not consistent with their personal values, and 4% felt ostracized by the genetics community because of their personal beliefs. The experience of such PVCs was positively correlated with religiosity (r = 0.35; P < 0.0001). GCs were more likely to experience PVCs than MDs or nurses (P = 0.013). Data from the interviews (N = 54) support these findings. A significant minority of genetic service providers are religiously observant and rely on their religious values to cope with distress. These individuals often experience difficulty reconciling their religious beliefs with the expectations of their profession, and sharing their beliefs with their colleagues and patients. Efforts should be made to prevent or reduce the secrecy surrounding personal faith and religion among genetics professionals. © 2009 Wiley‐Liss, Inc.
God and genes in the caring professions: Clinician and clergy perceptions of religion and genetics
Authors: Bartlett Virginia L. , Johnson Rolanda L.
Published: January 2009

Little is known about how care providers' perceptions of religion and genetics affect interactions with patients/parishioners. This study investigates clinicians' and clergy's perceptions of and experiences with religion and genetics in their clinical and pastoral interactions. This is an exploratory qualitative study designed to elicit care providers' descriptions of experiences with religion and genetics in clinical or pastoral interactions. Thirteen focus groups were conducted with members of the caring professions: physicians, nurses, and genetics counselors (clinicians), ministers and chaplains (clergy). Preliminary analysis of qualitative data is presented here. Preliminary analysis highlights four positions in professional perceptions of the relationship between science and faith. Further, differences among professional perceptions appear to influence perceptions of needed or available resources for interactions with religion and genetics. Clinicians' and clergy's perceptions of how religion and genetics relate are not defined solely by professional affiliation. These non‐role‐defined perceptions may affect clinical and pastoral interactions, especially regarding resources for patients and parishioners. © 2009 Wiley‐Liss, Inc.
Moving up the slippery slope: Mandated genetic screening on Cyprus
Authors: Cowan Ruth Schwartz
Published: January 2009

Many social scientists and bioethicists have argued that genetic screening is a new form of eugenics. Examination of the development of the quasi‐mandated screening program for β‐thalassemia in the Republic of Cyprus (1970–1984) demonstrates that there is nothing eugenic about modern genetic screening practices. The Cypriot screening program involves mandated premarital carrier screening, voluntary prenatal diagnosis (originally through fetoscopy, now through CVS), and voluntary termination of afflicted pregnancies—all at public expense. In the Republic of Cyprus, the mandating agency for genetic screening is the established church, so this examination also demonstrates that religious authorities with profound objections to abortion can balance that moral precept against others, such as the imperative to reduce suffering that sometimes conflict with it. © 2009 Wiley‐Liss, Inc.
Manual digital pressures during knuckle‐walking in chimpanzees (Pan troglodytes)
Authors: Wunderlich R.E. , Jungers W.L.
Published: January 2009

Considerable attention has been given to hand morphology and function associated with knuckle‐walking in the African apes because of the implications they have for the evolution of bipedalism in early hominins. Knuckle‐walking is associated with a unique suite of musculoskeletal features of the wrist and hand, and numerous studies have hypothesized that these anatomical features are associated with the dynamics of load distribution across the digits during knuckle‐walking. We collected dynamic digital pressures on two chimpanzees during terrestrial and simulated arboreal locomotion. Comparisons were made across substrates, limb positions, hand positions, and age categories. Peak digital pressures were similar on the pole and on the ground but were distributed differently across the digits on each substrate. In young animals, pressure was equally high on digits 2–4 on the ground but higher on digits 3 and 4 on the pole. Older animals experience higher pressures on digits 2 and 3 on the ground. Hand posture (palm‐in vs. palm‐back) influenced the distribution and timing of peak pressures. Age‐related increases in body mass also result in higher overall pressures and increased variation across the digital row. In chimpanzees, digit 5 typically bears relatively little load regardless of hand position or substrate. These are the first quantitative data on digital pressures during knuckle‐walking in hominoids, and they afford the opportunity to develop hypotheses about variation among hominoids and biomechanical models of wrist and forearm loading. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
Technical note: Virtual reconstruction of a fragmentary clavicle
Authors: Benazzi Stefano , Orlandi Marco , Gruppioni Giorgio
Published: January 2009

We report a procedure for the virtual reconstruction of incomplete human bones applicable to skeletal remains from archaeological excavations or to reconstructive and prosthetic surgery. To test the procedure, we reconstructed a fragmented left clavicle on the basis of the contralateral clavicle. The procedure involved 3‐D laser scanner acquisition of the left clavicle (complete but broken into two parts), the same manually reconstructed bone, and the intact right clavicle, which was mirror‐imaged and used as a reference for the reconstruction of the whole left clavicle. Because it was not possible to recognize homologous anatomical landmarks, on the two reference models (a mirror‐image copy of the right clavicle and the main fragment of the left), we identified three grids with an increasing number of corresponding landmarks, which constituted the framework of the deformation process. The three reconstructed digital models of the clavicle closely approximated the model of the original clavicle. They also showed that an increasing number of landmarks did not significantly improve the reconstructed model. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
Brief communication: Histology and micro CT as methods for assessment of facial suture patency
Authors: Reinholt Lauren E. , Burrows Anne M. , Eiting Thomas P. , Dumont Elizabeth R. , Smith Timothy D.
Published: January 2009

The extent of fusion in facial sutures has implications for topics ranging from biomechanics to phylogeny reconstruction. An unfortunate limitation of studying sutural fusion in skeletal specimens is that it is difficult to assess whether apparently patent sutures are in fact fused internally. Both histology and microcomputed tomography (CT) are potential tools for solving this, but relatively few studies have attempted to discern the limits of micro CT for visualization of microanatomical structures. We examined microanatomical aspects of facial sutures in adult cadaveric samples from captive bushbabies. Premaxillary and nasopremaxillary sutures were examined in serially sectioned snouts of four greater bushbabies (Otolemur garnettii) and four lesser bushbabies (Galago moholi). Sections containing sutures with osseous bridging were rated as “fused,” and the presence or absence of grooves on the external side was recorded. One bushbaby was studied using micro CT prior to physical sectioning. O. garnettii and two of the G. moholi show multiple foci of fusion. Histological examination confirmed that sutural fusion is limited to the internal surface in numerous sections, resulting in an external notch. Such points of internal fusion could be clearly visualized in raw CT slices. The presence of such notches suggests that external examination can underestimate the degree of suture fusion. Thus, microanatomical evidence may be needed to fully assess biomechanical correlates and phylogenetic interpretations based on fusion of facial sutures. Our results also indicate micro CT may be a useful tool to obtain this evidence. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
Control of Duplex Formation and Columnar Self‐Assembly with Heterogeneous Amide/Urea Macrocycles
Authors: Fischer Lucile , Decossas Marion , Briand Jean‐Paul , Didierjean Claude , Guichard Gilles
Published: January 2009

Ausgewogene Mischung: Cyclische Oligomere mit Harnstoff‐Amid‐Rückgrat (siehe Bild) bilden selbstorganisiert hoch geordnete hierarchische Strukturen: Abhängig vom Ausmaß der Vororientierung des Rückgrats können Säulen‐ oder Röhrenanordnungen mit parallelem oder antiparallelem Stapelungsmodus gezielt erhalten werden.

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Sequential Synthesis of Furans from Alkynes: Successive Ruthenium(II)‐ and Copper(II)‐Catalyzed Processes
Authors: Zhang Min , Jiang Huan‐Feng , Neumann Helfried , Beller Matthias , Dixneuf Pierre H.
Published: January 2009

In einer Eintopfreaktion lassen sich über zwei aufeinander folgende katalytische Reaktionen aus terminalen Alkinen 2,5‐disubstituierte Furane herstellen (siehe Schema; p‐TSA=para‐Toluolsulfonsäure): Zuerst bildet sich durch Dimerisierung eines terminalen Alkins und Addition eines Alkohols unter [RuCp*(NCMe)3]PF6‐Katalyse ein 1,3‐Dienylalkylether. Die nachfolgende Hydrolyse und Cyclisierung mithilfe eines CuCl2‐Katalysators ergeben dann die Zielverbindung.

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Oxindole Synthesis by Direct Coupling of CH and CH Centers
Authors: Jia Yi‐Xia , Kündig E. Peter
Published: January 2009

sp2 trifft sp3: Eine neuartige und effiziente Synthesemethode für 3,3‐disubstituierte Oxindole umfasst die direkte intramolekulare oxidative Kupplung eines Aryl‐C‐H‐ und eines C‐H‐Zentrums (siehe Schema; DMF=N,N‐Dimethylformamid).

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Room‐Temperature Palladium‐Catalyzed CH Activation: ortho‐Carbonylation of Aniline Derivatives
Authors: Houlden Chris E. , Hutchby Marc , Bailey Chris D. , Ford J. Gair , Tyler Simon N. G. , Gagné Michel R. , Lloyd‐Jones Guy C. , Booker‐Milburn Kevin I.
Published: January 2009

Effizient, unter 1 atm CO und bei 18 °C verläuft die Titelreaktion mit 5 Mol‐% [Pd(OTs)2(MeCN)2] als Präkatalysator. Abhängig vom Lösungsmittel sind entweder Anthranilate oder cyclische Imide in hohen Ausbeuten zugänglich (siehe Bild; BQ=Benzochinon, Ts=4‐Toluolsulfonyl).

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Revisiting Prussian Blue Analogues with Solid‐State MAS NMR Spectroscopy: Spin Density and Local Structure in [Cd3{Fe(CN)6}2]⋅15 H2O
Authors: Flambard Alexandrine , Köhler Frank H. , Lescouëzec Rodrigue
Published: January 2009

No legendary Prussian order! The distribution of vacancies in Prussian blue analogues is not random, and the spin density on the Cd2+ ion varies depending on the number of paramagnetic ions in its surroundings. This conclusion follows from 113Cd solid‐state magic‐angle spinning NMR studies of [Cd3{Fe/Co(CN)6}2]⋅15 H2O, where the presence of small but significant spin density on the observed 113Cd nucleus leads to improved spectral resolution.

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Sequential Synthesis of Furans from Alkynes: Successive Ruthenium(II)‐ and Copper(II)‐Catalyzed Processes
Authors: Zhang Min , Jiang Huan‐Feng , Neumann Helfried , Beller Matthias , Dixneuf Pierre H.
Published: January 2009

Step in time: 2,5‐Disubstituted furans can be prepared from terminal alkynes in one pot using two successive catalytic reactions (see scheme; p‐TSA=para‐toluenesulfonic acid). First, a 1,3‐dienyl alkyl ether is produced by the dimerization of a terminal alkyne and addition of an alcohol catalyzed by [RuCp*(NCMe)3][PF6]. Then, consecutive hydrolysis and cyclization catalyzed by CuCl2 provides the 2,5‐disubstituted furan.

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Synthesis and properties of organosoluble polyimides based on novel flourene‐ring containing diacetamido‐diamine
Authors: Ghaemy M. , Barghamadi M.
Published: January 2009

A new diacetamido‐diamine monomer, N′‐[7‐(acetyl‐4‐aminoanilino)‐9,9‐dioctylflouren‐2‐yl]‐N′‐4‐aminophenyl) acetamide (ADOAc), with flourene‐based structure was prepared from the reaction of 4‐aminoacetanillide with 2,7‐dibromo‐9,9‐dioctylfluorene in the presence of 10 mol % CuI, 20 mol % N,N′‐dimethylethylene diamine as catalyst and K2CO3 as base. Two new flourene‐ring containing polyimides were prepared from the reaction of ADOAc with aromatic dianhydrides such as pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) via chemical imidization of poly(amic acid). The new diamine and the related polyimides were characterized by using conventional methods such as FT‐IR, NMR, and elemental analysis. The polyimides obtained from the reaction of ADOAc with PMDA (PIa) and of ADOAc with BTDA (PIb) had inherent viscosity of 0.49 and 0.58 dL/g respectively, and showed excellent solubility in a variety of organic solvents. The polyimides of PIa and PIb showed excellent thermal stability with 10% weight loss in nitrogen atmosphere at temperatures of 418°C and 407°C and Tg of 172°C and 167°C, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of poly(N‐tert‐butylacrylamide‐co‐acrylamide) ferrogel
Authors: Caykara Tuncer , Yörük Döne , Demirci Serkan
Published: January 2009

Magnetic‐field‐sensitive gel, called ferrogel, was prepared by a two‐step procedure in which first step requires synthesis of the poly(N‐tert‐butylacrylamide‐co‐acrylamide) [P(NTBA‐co‐AAm)] hydrogel and during second step magnetite (Fe3O4) particles were formed in the hydrogel via coprecipitation of Fe(II) and Fe(III) ions in alkaline medium at 70°C. The obtained ferrogel was characterized by attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy combined with energy dispersive spectroscopy, and electron spin resonance measurements. The magnetic responsive of the ferrogel was also investigated by applying magnetic field to the ferrogel. The extent of a bending degree of the ferrogel depends on the applied magnetic field strength. In addition, the magnetic responsive studies also indicated that formed magnetite content in the hydrogel is high enough to achieve considerable magnetic response to external magnetic field. As a result, the P(NTBA‐co‐AAm) ferrogel may be useful for potential applications in magnetically controlled drug release systems, magnetic‐sensitive sensors, and pseudomuscular actuators. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Immobilization of α‐amylase onto chitosan and its amino acid condensation adducts
Authors: El‐Ghaffar M. A. Abd , Hashem M. S.
Published: January 2009

α‐Amylase from Bacillus subtilis was immobilized on insoluble chitosan and its amino acid (L‐glutamic acid and 4‐aminobutyric acid) condensation adducts with the direct covalent attachment method and with glutaric dialdehyde (GDA) as a crosslinking agent. The immobilization process was carried out at 25°C and pH 6.9, and the maximum retained activity was obtained with 3 mg of α‐amylase. The properties of the immobilized α‐amylase were investigated and compared with those of the free α‐amylase. For the assays carried out via the crosslinking method at 25°C and pH 6.9, the retained activities were found to be 68.59, 97.36, and 79.50% for chitosan, chitosan–L‐glutamic acid, and chitosan–4‐aminobutyric acid crosslinked with 1% GDA, respectively. The immobilized α‐amylase had better stability and higher retained activities with respect to the pH, temperature, and storage stability than the free α‐amylase. In the repeated‐use experiments, the α‐amylase immobilized with chitosan–GDA (1%) retained about 46.45% of its original activity after 25 uses. In contrast, the activities of α‐amylase immobilized on chitosan–L‐glutamic acid–GDA (1%) and chitosan–4‐aminobutyric acid–GDA (1%) did not change after 11 and 8 uses, respectively. The retained activities after 25 uses were 79 and 71% with respect to the original activity for the aforementioned carriers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of oxidation level on the dual modification of banana starch: The mechanical and barrier properties of its films
Authors: Zamudio‐Flores Paul Baruk , Bautista‐Baños Silvia , Salgado‐Delgado René , Bello‐Pérez Luis Arturo
Published: January 2009

Banana starch was oxidized at three different levels and then acetylated. The double‐modified starch was used for film preparation. The physical, mechanical, and barrier properties were tested. The oxidation level increased the whiteness of the film, and the second modification (acetylation) did not affect this parameter. The solubility increased with temperature and oxidation level. However, acetylation decreased the solubility value. At the longest storage times, the solubility decreased because of starch reorganization inside the polymeric matrix. In general, oxidation increased the tensile strength of the films, and a slight increase was observed when the oxidized starch was acetylated. This effect was more noticeable at the longest storage time. The oxidation level decreased the percentage elongation at break, and a slight effect due to acetylation was observed. The film of oxidized–acetylated starch showed a higher elastic modulus value than its oxidized counterpart. The water vapor permeability increased with oxidation level, but the acetylation decreased this parameter. The oxidation increased the hydrophilic character of the starch because of the formation of carbonyl and carboxyl groups that showed more affinity for water molecules. When the oxidized banana starch was acetylated, a decrease in the water vapor permeability was found because the acetylation increased the hydrophobic character of the starch due to the ester group. Films prepared with the double‐modified banana starch had some improved physical, mechanical, and barrier properties, and they may be used in specific applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Guanidinylated poly(allyl amine) as a gene carrier
Authors: Yu Jia‐Hui , Huang Jin , Jiang Hu‐Lin , Quan Ji‐Shan , Cho Myung‐Haing , Cho Chong‐Su
Published: January 2009

Guanidinylated poly(allyl amine) (GA) was synthesized and used as a gene carrier. The degree of guanidinylation in GA increased linearly when the feed ratio of guanidino groups in 1H‐pyrazole‐1‐carboxamidine to amino groups in poly(allyl amine) (PA) was below 0.7, and the amino groups of poly(allyl amine) with a weight‐average molecular weight of 15,000 (PA15) were almost replaced with guanidino groups when the ratio reached 2. GA showed good plasmid condensation and protection ability. Nanoparticles with a narrow size distribution, good dispersity, and spherical shape could be assembled between GA and DNA. With an increase in the N/P ratio [where N is the amount of nitrogen in the polycation (for GA, three nitrogens per guanidino group) and P is the amount of plasmid phosphate in the DNA as moles] or the degree of guanidinylation, the ζ‐potential of GA/DNA nanoparticles increased, whereas the sizes of GA/DNA nanoparticles decreased sharply with increasing N/P ratios. Compared with polyethylenimine with a weight‐average molecular weight of 25,000 and PA15, GA essentially showed decreased cytotoxicity to HeLa, 293T, and HepG2 cell lines, and guanidinylated PA15 exhibited the lowest cytotoxicity. Guanidinylation of PA enhanced its gene transfection. This enhancement was dependent on the degree of guanidinylation and the cell lines. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Increasing the resistance of poly(ether imide) to solvents by blending with poly(trimethylene terephthalate)
Authors: Ramiro J. , Eguiazábal J. I. , Nazábal J.
Published: January 2009

We studied the sorption behavior of poly(ether imide) (PEI) upon the addition of minor amounts (10 and 30%) of miscibilized poly(trimethylene terephthalate) (PTT) under acetone and other common solvent environments. Significant solvent sorption (maximum solvent sorption = 8–12 wt %) and changes in mechanical properties were observed only in the case of acetone. The sorption of acetone was Fickian and partially irreversible. Both sorption and solubility decreased markedly upon PTT addition to PEI, most likely as a result of a blending‐induced decrease in the free volume. The decreases in the modulus were attributed to plasticization, and the mixed effects on the elongation at break were attributed to the combined effects of fast plasticization and slower swelling. The joint effects of applied stress and the presence of acetone were studied with creep tests. In these tests, a combination of a free volume increase, plasticization, and superficial cracking of PEI was proposed to occur. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal degradation kinetics and lifetime prediction of poly(aryl ether ketone)s containing 2,6‐naphthalene moieties
Authors: Liu Si‐Jie , Hou Xiang , Fang Chi‐Guang , Ma Rong‐Tang , Jiang Zhen‐Hua
Published: January 2009

The kinetics of thermal degradation and lifetime of poly(aryl ether ketone) containing 2,6‐naphthalene moieties (PANEK) in nitrogen and in air were studied with dynamic thermogravimetry. The results showed that the thermal stability of PANEK in air was substantially less than that in nitrogen. The kinetic parameters for PANEK, including the activation energy, the reaction order; and the frequency factor of the degradation reaction, were analyzed with the Ozawa method. The lifetime of PANEK decreased gradually from 1.09 × 107 to 0.65 × 102 min as the temperature increased from 200 to 400°C in air and from 2.12 × 108 to 3.30 × 102 min in nitrogen. These lifetime parameters indicated that the service/process temperature had a strong influence on PANEK. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical properties and fracture behavior of polypropylene reinforced with polyaniline‐grafted short glass fibers
Authors: Flores O. , Romo‐Uribe A. , Romero‐Guzmán M. E. , González A. E. , Cruz‐Silva R. , Campillo B.
Published: January 2009

This research was focused on the mechanical properties of electrically conducting composites based on polyaniline (PAn)‐coated short glass fibers (SGFs) immersed in an isotactic polypropylene (iPP) matrix. In these composites, PAn was actually grafted onto the SGF surface, and so it was denoted PAn‐g‐SGF. The tensile, flexural, and interlaminar fracture toughness was investigated. To study the influence of PAn‐g‐SGF, three different concentrations (10, 20, and 30 wt %) were melt‐mixed in the iPP resin with a batch mixer. X‐ray patterns of the as‐molded plaques of iPP and its composites showed an isotropic orientation. Uniaxial tensile deformation revealed that the Young's modulus and tensile stress increased as the concentration of PAn‐g‐SGF increased; on the other hand, the strain at failure was significantly reduced (by 2 orders of magnitude) with respect to the neat iPP. Scanning electron microscopy studies on the failure specimens indicated that the significant reduction of the strain at failure was due to the low interfacial bonding between the fibers and the surrounding matrix. Moreover, X‐ray scattering analyses of the fractured regions showed that the uniaxial deformation enabled significant molecular orientation in the iPP, whereas the fractured composites remained isotropic. Detailed scanning electron microscopy analyses showed that the fracture mechanism arose from the fracture of the PAn‐g‐SGFs; the percolated PAn‐g‐SGFs formed a path for the stress transfer. Because the failure was dominated by both filler decohesion and polymeric chain rupture, the strength was not influenced significantly by the amount of PAn‐g‐SGFs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Engineering performance and material viscoelastic analyses along a compounding line for silica‐based compounds. I. Mixing line performance analysis
Authors: Nijman G. , Leblanc J. L.
Published: January 2009

In the tire industry, the preparation of silica‐filled compounds requires relatively complicated compounding operations, which involve several dumping, cooling, and remixing steps, to eventually obtain quality final batches. The various and complex sets of events that take place along the mixing line remain, however, poorly understood. The objectives of this study, reported in two companion articles, were to deepen the understanding of silica–silane compounding operations. Two approaches were used in parallel: first, we performed a deep analysis of the engineering performance of an existing—and successful—mixing line by paying attention to the various curves that are nowadays recorded during internal mixing, and second, we studied the variations of the nonlinear viscoelastic properties along the mixing line using so‐called Fourier transform rheometry, implemented on a commercial torsional dynamic rheometer. The first article of the series is devoted to the performance analysis of the mixing line through mixing trials along an industrial line. Silica dispersion and the treatment with silane were initiated during a master‐batching process; then, two remixing steps were performed to achieve the right silanization degree. Curatives were added during a final mixing step. Mixing signatures, containing information such as mixing power, ram position, compound temperature, and rotor speed, gave some insight to the dispersion–silanization processes and, among other results, showed that the dumping, cooling, and remixing of the compound comprised a more efficient process than the maintenance of a very high batch temperature for an extended time, essentially because one could make use of stress‐induced dispersing effects. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of poly(methyl methacrylate) particles with different initial temperature rising ramps on size distribution in dispersion polymerization
Authors: Zhang Congyun , Wei Qun
Published: January 2009

The initial heating velocity was surprisingly found to play a key role in the size distribution of the resulting polymer particles in the dispersion polymerization of methyl methacrylate. Monodisperse poly(methyl methacrylate) particles had to be prepared by the mild and gradual increase of the reaction temperature. A universal conclusion was drawn from a series of experiments: the more slowly the initial temperature rose, the more the dispersity of the poly(methyl methacrylate) particles improved with a monomer concentration of 5–20 wt %, a 2,2‐azobisisobutyronitrile concentration of 0.5–3 wt %, and a polyvinylpyrrolidone K‐30 concentration of 20–60 wt %. The optimal heating velocity was 10–15°C/h. A heating ramp faster than 15°C/h led to polydisperse polymer particles or a poor dispersity. These interesting phenomena might be explained as a delicate balance between the formation rate of radicals and the capture of oligomer chains in the continuous phase when a slow heating strategy was used. For comparison, the dispersion polymerization of styrene and glycidyl methacrylate in an alcoholic medium was also investigated. Slow heating was slightly disadvantageous for the dispersity of polystyrene and poly(glycidyl methacrylate). Presetting at the polymerization temperature was practical for the production of monodisperse polystyrene and poly(glycidyl methacrylate). Furthermore, either a low reaction temperature or a long heating time caused the coagulation of poly(glycidyl methacrylate) or polydisperse particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of an anion‐exchange membrane by the amination of chlorinated polypropylene and polyethyleneimine at a low temperature and its ion‐exchange property
Authors: Hong Joo‐Hee , Park Myung‐Chul , Hong Sung‐Kyu , Kim Byoung‐Sik
Published: January 2009

An anion‐exchange membrane was prepared by the amination of chlorinated polypropylene and polyethyleneimine at a low temperature and was investigated with respect to not only its physical properties but also its electrochemical properties. The degrees of amination were 50.16, 53.76, 57.11, and 65.29% at 30, 40, 50, and 55°C, respectively. The base polymer membrane had no water uptake, whereas that of the aminated polymer membrane was 0.254, 0.296, 0.298, and 0.319 g of H2O/g of dry membrane, respectively, with increasing amination. The prepared membranes possessed an ion‐exchange capacity in the range of 1.257–2.000 mequiv/g of dry membrane and a fixed ion concentration in the range of 4.492–6.261 mequiv/g of H2O. The ionic conductivity of the aminated polymer membrane was highest when the water uptake was highest. Those of the prepared membrane were in the range of 0.89 × 10−2 to 1.36 × 10−2 S/cm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Nucleation mechanism and morphology of polystyrene/Fe3O4 latex particles via miniemulsion polymerization using AIBN as initiator
Authors: Luo Ying‐Da , Dai Chi‐An , Chiu Wen‐Yen
Published: January 2009

In this study, oil‐based magnetic Fe3O4 nanoparticles were first synthesized by a coprecipitation method followed by a surface modification using lauric acid. Polystyrene/Fe3O4 composite particles were then prepared via miniemulsion polymerization method using styrene as monomer, 2,2′‐azobisisobutyronitrile (AIBN) as initiator, sodium dodecyl sulfate (SDS) as surfactant, hexadecane (HD) or sorbitan monolaurate (Span20®) as costabilizer in the presence of Fe3O4 nanoparticles. The effects of Fe3O4 content, costabilizer, homogenization energy during ultrasonication, and surfactant concentration on the polymerization kinetics (e.g., conversion), nucleation mechanism, and morphology (e.g., size distributions of droplets and latex) of composite particles were investigated. The results showed that at high homogenization energy, an optimum amount of SDS and hydrophobic costabilizer was needed to obtain composite particles nucleated predominately by droplet nucleation mechanism. The morphology of the composite particles can be well controlled by the homogenization energy and the hydrophobicity of the costabilizer. The magnetic composite particles can be made by locating Fe3O4 inside the latex particles or forming a shell layer on their PS core surface depending on the aforementioned polymerization conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Diffusion behavior of water and sulfuric acid in epoxy/organoclay nanocomposites
Authors: Abacha N. , Kubouchi M. , Sakai T. , Tsuda K.
Published: January 2009

The research on polymer‐layered silicate nanocomposites is currently an expanding field of study because they often exhibit a wide range of improved properties over their unmodified starting polymers. Epoxy/organoclay nanocomposites have been prepared by intercalating epoxy into the organoclay montmorillonite. The intercalation and/or exfoliation of the clay within the nanocomposite were monitored using X‐ray diffraction and transmission electron microscopy. Diffusion was studied through epoxy samples containing up to 10 phr of organically treated montmorillonite following the gravity method. The water and sulfuric acid diffusion within the epoxy‐based nanocomposites were evaluated in terms of diffusivity, weight change and penetration depth of the sulfuric acid element S as function of immersion time and immersion temperature. An investigation of the resistance of epoxy nanocomposite to a corrosive environment by immersion into sulfuric acid at elevated temperature was performed. The effect of the degree of exfoliation of the clay on moisture barrier effect and corrosion resistance is specifically studied. The data has been compared to those obtained from the neat epoxy resin to evaluate the diffusion properties of the nanocomposites. It was found that the diffusion of water and that of acid do not obey Fick's law, and that the higher the organoclay content the higher weight change was obtained. The presence of the organoclay enhanced the diffusivity and delayed the penetration of the sulfuric acid. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009