bluuebunny/crossref_metadata_2025 huggingface dataset:
A Microfluidic Approach to Chemically Driven Assembly of Colloidal Particles at Gas–Liquid Interfaces
Authors: Park Jai Il , Nie Zhihong , Kumachev Alexander , Abdelrahman Ahmed I. , Binks Bernard P. , Stone Howard A. , Kumacheva Eugenia
Published: March 2009

Die Auflösung von CO2‐Blasen in einer Suspension von Kolloidpartikeln induziert auf chemischem Weg die Anlagerung von Partikeln auf der Oberfläche der geschrumpften Blasen. Dieser Ansatz führt schnell zu Blasen mit einem Kolloidüberzug und exakt festgelegter Größe.

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Ordered Poly(p‐phenylene)/Layered Double Hydroxide Ultrathin Films with Blue Luminescence by Layer‐by‐Layer Assembly
Authors: Yan Dongpeng , Lu Jun , Wei Min , Han Jingbin , Ma Jing , Li Feng , Evans David G. , Duan Xue
Published: March 2009

Himmelblau: Ein anionisches Poly(para‐phenylen) und Mg‐Al‐Hydroxid‐Schichten wurden zu sehr dünnen geordneten Filmen mit definierter blauer Fluoreszenz (siehe Bild; Nummer: Zahl der Doppelschichten) und hoher Photostabilität kombiniert. Die Filme wirken auf Valenzelektronen als Anordnungen von Quantentöpfen.

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A Microfluidic Approach to Chemically Driven Assembly of Colloidal Particles at Gas–Liquid Interfaces
Authors: Park Jai Il , Nie Zhihong , Kumachev Alexander , Abdelrahman Ahmed I. , Binks Bernard P. , Stone Howard A. , Kumacheva Eugenia
Published: March 2009

Bubbling up: Dissolution of CO2 bubbles in a suspension of colloidal particles chemically induces the assembly of particles on the surface of shrunken bubbles, and thus yields rapid continuous formation of a colloidal armor. This approach maintains the high colloidal stability of particles in bulk, has increased productivity, and allows the formation of bubbles with precisely controlled dimensions.

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Ablation and thermal properties of ethylene–propylene–diene elastomer composites reinforced with polysulfonamide short fibers
Authors: Jia Xiaolong , Li Gang , Yu Yunhua , Sui Gang , Liu Haiyang , Li Ya'nan , Li Peng , Yang Xiaoping
Published: March 2009

Polysulfonamide (PSA) short fiber/ethylene–propylene–diene elastomer (EPDM) composites were prepared as high‐performance thermal insulators. The pyrolysis products and thermal stabilities of the PSA fiber and aramid fiber were analyzed. The ablation and thermal properties of the PSA/EPDM composites were compared with those of the aramid/EPDM composites. The degradation peak temperature of the PSA fiber was 100°C higher than that of the aramid fiber. With the fiber content increasing, the ablation rates of both composites decreased up to 10 phr and subsequently increased, whereas the thermal conductivities of both composites increased linearly. In comparison with the aramid/EPDM composites, the ablation rate and thermal conductivity of the PSA/EPDM composites were lower, whereas the thermal degradation temperature and limiting oxygen index of the PSA/EPDM composites were higher. Dynamic mechanical thermal testing and morphology observations revealed that strong interfacial bonding between the fiber and the matrix was developed in the PSA/EPDM composites, and it was beneficial for improving the ablation properties of the composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of PVA/PAN bicomponent nanofiber via electrospinning and selective dissolution
Authors: Kim Mi Nae , Koh Joonseok , Lee Yujin , Kim Hyungsup
Published: March 2009

Bicomponent polymer solutions were prepared from two immiscible polymers, poly(vinylalcohol) (PVA) and polyacrylonitrile (PAN), and then used to prepare films and electrospun fibers. The miscibility and the surface morphology of the bicomponent polymer systems were determined. There was a strong relationship between the diameter of the electrospun fibers and the blend ratio used. By applying selective dissolution, using solvents such as hot water, acetic acid, or N,N‐dimethylformamide, to the films and fibers, one polymer component was removed selectively without affecting the other component. This resulted in a decrease in the diameter of the electrospun fibers and the formation of grooves, pores, and craters on the fiber surface. The width of the grooves decreased as the bicomponent polymer content increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermosensitive phase transition kinetics of poly(N‐isopropylacryl amide‐co‐acrylamide) microgel aqueous dispersions
Authors: Wang Qin , Zhao Yanbing , Xu Huibi , Yang Xiangliang , Yang Yajiang
Published: March 2009

Thermosensitive poly(N‐isopropylacrylamide‐co‐acrylamide) microgel particles were prepared through precipitation polymerization. The diameters of the microgel particles were in the range of 220–270 nm and showed a monodispersion. The lower critical solution temperatures (LCST) of the microgel dispersions were measured by dynamic light scattering and turbidimetric analysis. The results indicated that the LCST increased with an increase of acrylamide (AAm) content in the copolymer composition. The kinetics of the thermosensitive phase transitions of the microgel particles were investigated by time‐course UV–vis spectroscopy. The results indicated that the higher the content of AAm in copolymer composition, the more time is required for equilibrium deswelling and the less time required for equilibrium swelling. In addition, the time required for equilibrium deswelling decreased with an increase of the content of the microgel particles in dispersions. By contrast, the time required for equilibrium swelling increased slightly. Thus, a suitable LCST and time required for equilibrium of phase transition can be achieved by adjusting the molar ratio of the comonomers in the microgels and the content of the microgel particles in dispersions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Manipulation of polymer layer characteristics by electrochemical polymerization from mixtures of aniline and ortho‐phenylenediamine monomers
Authors: Roković M. Kraljić , Jurišić A. , Žic M. , Duić Lj. , Schauperl Z.
Published: March 2009

The influence of adding ortho‐phenylenediamine (OPDA) during the polymerization of aniline on the characteristics of the resulting polymer film was examined. When using a platinum electrode, the deposits were obtained from solutions containing 0.1 mol dm−3 aniline and 1, 5, or 10 mmol dm−3 OPDA. The deposits were also prepared from solutions containing 0.5 mol dm−3 aniline and 5, 10, or 50 mmol dm−3 OPDA. In both cases, 3 mol dm−3 phosphoric acid solution was used as a supporting electrolyte. The characteristics of the obtained layers were investigated through the catalytic effect of different polymer layers on hydroquinone/quinone (H2Q/Q) test redox system. The results obtained confirm the earlier established catalytic effect on the potential of the redox reaction by shifting it to more reversible values. However, as the concentration of OPDA was increased, the resulting limiting current decreased, thus indicating in the presence of OPDA a lower population of the available active centers necessary for the catalytic reaction to proceed. The influence of OPDA on polymer characteristics was also studied by using scanning electron microscopy as well as electrochemical impedance spectroscopy. The polymer was synthesized on a stainless steel electrode (13% Cr) from a solution containing 0.5 mol dm−3 aniline and 5, 10, or 50 mmol dm−3 OPDA. The layers were tested in chloride‐containing solutions by monitoring the open circuit potential. The results obtained suggest that, by increasing the concentration of OPDA, the time of OCP in the passive region of stainless steel is prolonged. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The enhanced mechanical properties of a covalently bound chitosan‐multiwalled carbon nanotube nanocomposite
Authors: Cao Xiaodong , Dong Hua , Li Chang Ming , Lucia Lucian A.
Published: March 2009

In the present work, chitosan (CS)‐grafted multiwalled carbon nanotube (MWCNT) nanocomposites were prepared via covalently bonded CS onto MWCNTs that had weight fractions of MWCNTs ranging from 0.1 to 3.0 wt % by a simple method of solution casting. The structure, morphology, and mechanical properties of the films were investigated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, optical microscopy, wide‐angle X‐ray diffraction, contact angle, and tensile testing. The results indicated that the CS chains were attached onto the MWCNTs successfully via covalent linkages. More interestingly, the MWCNTs provided a matrix that facilitated the crystallization of CS. Compared with the pure CS, the tensile strength and Young's modulus of the nanocomposites were enhanced significantly from 39.6 to 105.6 MPa and from 2.01 to 4.22 GPa with an increase in the MWCNT loading level from 0 to 3.0 wt %, respectively. The improvement in the tensile strength and modulus were ascribed to the uniform dispersion of MWCNTs covalently linked to the CS matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Electrohydrodynamic liquid atomization of biodegradable polymer microparticles: Effect of electrohydrodynamic liquid atomization variables on microparticles
Authors: Meng Fanzheng , Jiang Yi , Sun Zhihui , Yin Yizi , Li Yanyan
Published: March 2009

The exploration of a method to tailor a biodegradable polymer into microparticles/nanoparticles with a desirable morphology and size may result in their enhanced performance as biomedical devices for drug delivery and simplify the preparation process. A modified electrohydrodynamic liquid atomization (EHDA) process is reported here for the preparation of poly(lactic‐co‐glycolic acid) (PLGA) microparticles. To understand systematically the EHDA method for the preparation of PLGA microparticles, PLGAs of four different molecular weights were electrosprayed under different conditions involving changes in the applied potential, liquid flow rate, polymer concentration, and solvent. The results show that the right concentration range of PLGA is key for electrospraying the spherical particles. A solution with a low‐molecular‐weight PLGA has a wider concentration range for electrospraying into spherical particles than a solution with a high‐molecular‐weight PLGA. At the concentration at which spherical particles are formed, the diameter of the as‐sprayed particles is not affected substantially by the applied potential and PLGA molecular weight, but it increases monotonically with the liquid flow rate and PLGA concentration. Experimentation further demonstrated that low electric conductivity, a low dielectric constant, and a high vapor pressure of chloroform are favorable for controlling the EHDA process to obtain quasi‐monodisperse particles. The addition of the solvent N,N‐dimethylformamide with opposite solvent properties extremely disturbs the stability of the EHDA process and, at the same time, produces smaller and polydisperse particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of artificial perspiration and cleaning chemicals on the mechanical and chemical properties of ballistic materials
Authors: Chin Joannie , Petit Sylvain , Forster Amanda , Riley Michael , Rice Kirk
Published: March 2009

During routine field use of soft body armor, the ballistic panels become saturated with perspiration. This condition motivates the user to clean and/or deodorize the armor, and anecdotal evidence is given for various methods used to accomplish this. Although the cleaning/deodorization is usually performed on the armor liners and coverings, there is concern that the chemicals could seep into the ballistic panels and damage the fibers. The purpose of this study was to assess the effect of artificial perspiration and cleaning chemicals on the mechanical and chemical properties of aramid, poly(p‐phenylene benzobisoxazole), and ultrahigh‐molecular‐weight polyethylene yarns after controlled cycles of exposure to artificial perspiration and dilute solutions of common cleaning chemicals. It was observed that the effect of the artificial perspiration on the properties of all of the materials tested was the same as that of water alone. Of all of the cleaning chemicals used, only chlorine bleach had a detrimental effect on the yarn properties. All other cleaning chemicals had the same effect as water alone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Wood particle/high‐density polyethylene composites: Thermal sensitivity and nucleating ability of wood particles
Authors: Bouafif Hassine , Koubaa Ahmed , Perré Patrick , Cloutier Alain , Riedl Bernard
Published: March 2009

The thermal sensitivity, nucleating ability, and nonisothermal crystallization of high‐density polyethylene (HDPE) with different wood fillers during wood/HDPE melt processing were investigated with thermogravimetric analysis and differential scanning calorimetry. The results showed that the wood degraded at a lower temperature than HDPE. The thermal decomposition behavior was similar across wood species. The most remarkable dissimilarities were observed between wood and bark in the decomposition rate around a processing temperature of 300°C and in the peak temperature location for cellulose degradation. The higher degradation rate for bark was explained by the devolatilization of extractives and the degradation of lignin, which were present in higher amounts in pine bark. The nucleating ability for various wood fillers was evaluated with the crystalline weight fraction, crystal conversion, crystallization half‐time, and crystallization temperature of the HDPE matrix. The nucleation activity improved with the addition of wood particles to the HDPE matrix. However, no effect of wood species on the crystal conversion was found. For composites based on semicrystalline matrix polymers, the crystal conversion may be an important factor in determining the stiffness and fracture behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Characterization of cyanobacterial β‐carotene ketolase and hydroxylase genes in Escherichia coli, and their application for astaxanthin biosynthesis
Authors: Scaife Mark A. , Burja Adam M. , Wright Phillip C.
Published: March 2009

Carotenoid biosynthesis is highly conserved and well characterized up to the synthesis of β‐carotene. Conversely, the synthesis of astaxanthin from β‐carotene is less well characterized. Regardless, astaxanthin is a highly sought natural product, due to its various industrial applications and elevated antioxidant capacity. In this article, 12 β‐carotene ketolase and 4 β‐carotene hydroxylase genes, isolated from 5 cyanobacterial species, are investigated for their function, and potential for microbial astaxanthin synthesis. Further, this in vivo comparison identifies and applies the most promising genetic elements within a dual expression vector, which is maintained in Escherichia coli. Here, combined overexpression of individual β‐carotene ketolase and β‐carotene hydroxylase genes, within a β‐carotene accumulating host, enables a 23.5‐fold improvement in total carotenoid yield (1.99 mg g−1), over the parental strain, with >90% astaxanthin. Biotechnol. Bioeng. 2009;103: 944–955. © 2009 Wiley Periodicals, Inc.
A high efficient method of constructing recombinant Bombyx mori (silkworm) multiple nucleopolyhedrovirus based on zero‐background Tn7‐mediated transposition in Escherichia coli
Authors: Sun Jing Chen , Zhang Er Hui , Yao Lun Guang , Zhang Hong Ling , Jin Peng Fei
Published: March 2009

A high efficient way for generation of recombinant Bombyx mori (silkworm) multiple nucleopolyhedrovirus by Tn7‐mediated transposition in Escherichia coli was performed. The new system consists of a conditional replication donor vector pRCDM and an attTn7 site blocked E. coli containing BmNPV‐Bacmid. The donor vector contains a replication origin derived from R6Kγ, which propagated only in host cells with pir gene expression decreased in the transposition background greatly. Compared with original vector derived from pUC, the transposition efficiency increased from 5.7 to 66% (≈10 fold) when using conditional replication vector pRCDM transposition into original BmDH10Bac. A further effort to decrease the transposition background was made by blocking the attTn7 site in host E. coli genome. The resulting attTn7 occupied BmDH10BacΔTn7 resulted in a significant increase from 5.7 to 23% (≈4 fold) in the efficacy of generate recombinant BmNPV Bacmid by transposition. Furthermore, the transposition of BmDH10BacΔTn7 with pRCDM resulted typically in 100% white colonies, and it indicated that a zero transposition background was accomplished. This high efficient and zero background transposition system provides a new simple and rapid method for construction of recombinant BmNPV used to express target genes or produce gene‐delivery virus particles in silkworm. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
A digital simulation of the vibration of a two‐mass two‐spring system
Authors: Lee Wei‐Pin , Lu Ming‐Shiun
Published: March 2009

In this study, we developed a computer program to simulate the vibration of a two‐mass two‐spring system by using Visual BASIC. Users can enter data for the two‐mass two‐spring system. The software will derive the eigenvalue problem from the input data. Then the software solves the eigenvalue problem and illustrates the results numerically and graphically on the screen. In addition, the program uses animation to demonstrate the motions of the two masses. The displacements, velocities, and accelerations of the two bodies can be shown if the corresponding checkboxes are selected. This program can be used in teaching courses, such as Linear Algebra, Advanced Engineering Mathematics, Vibrations, and Dynamics. Use of the software may help students to understand the applications of eigenvalue problems and related topics such as modes of vibration, natural frequencies, and systems of differential equations. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 563–573, 2010; View this article online at wileyonlinelibrary.com; DOI 10.1002/cae.20241
Fine‐Tuning of Catalytic Properties of Catechol 1,2‐Dioxygenase by Active Site Tailoring
Authors: Caglio Raffaella , Valetti Francesca , Caposio Patrizia , Gribaudo Giorgio , Pessione Enrica , Giunta Carlo
Published: March 2009

Choosing chloro: By reshaping the catalytic pocket of a catechol 1,2‐dioxygenase through a structural route alternative to evolution, novel engineered chlorocatechol dioxygenase‐like enzymes were obtained. Variants show an inversion of specificity with a preference for 4‐chlorocatechol and activity on the rarely recognised substrate 4,5‐dichlorocatechol.

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Catechol 1,2‐dioxygenases and chlorocatechol dioxygenases are FeIII‐dependent enzymes that do not require a reductant to perform the ortho cleavage of the aromatic ring. The reaction mechanism is common to the two enzymes, and active‐site residues must play a key role in the fine‐tuning of specificity. Protein engineering was applied for the first time to the catalytic pocket of a catechol 1,2‐dioxygenase by site‐specific and site‐saturation mutagenesis with the purpose of redesigning the pocket shape for improved catalysis on bulky derivatives. Mutants were analysed for changes in kinetic parameters: variants for residue 69 show an inversion of specificity with a preference towards 4‐chlorocatechol (decrease of KM by a factor of 20) and activity on the rarely recognised substrate 4,5‐dichlorocatechol, thus creating a novel, engineered chlorocatechol dioxygenase. A L69A substitution conveys gain‐of‐function activity towards 4‐tert‐butylcatechol. Mutations of position 72 enhance kcat towards chlorinated substrates. The biphasic Arrhenius plot observed in A72S suggests the involvement of a dynamic switch in the fine regulation of the enzyme.
Recent Advances in Production of Bioethanol from Lignocellulosic Biomass
Authors: Kumar S. , Singh S. P. , Mishra I. M. , Adhikari D. K.
Published: March 2009

Ethanol is considered the most potential next generation automotive fuel because it is carbon‐neutral and could be produced from renewable resources like lignocellulosic biomass. There are some technological barriers such as pretreatment, saccharification of cellulose and hemicellulose matrix, and simultaneous fermentation of hexose and pentose sugars which needs to be addressed for efficient conversion of lignocellulosic biomass to bioethanol. This paper reviews the various process options and kinetic models adopted towards resolving the technological challenges to develop a low‐cost commercial process.
Exploring, Tuning, and Exploiting the Basicity of Hydrotalcites for Applications in Heterogeneous Catalysis
Authors: Debecker Damien P. , Gaigneaux Eric M. , Busca Guido
Published: March 2009

Basic catalysis! The basic properties of hydrotalcites (see picture) make them attractive for numerous catalytic applications. Probing the basicity of the catalysts is crucial to understand the base‐catalysed processes and to optimise the catalyst preparation. Various parameters can be employed to tune the basic properties of hydrotalcite‐based catalysts towards the basicity demanded by each target chemical reaction.

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Hydrotalcites offer unique basic properties that make them very attractive for catalytic applications. It is of primary interest to make use of accurate tools for probing the basicity of hydrotalcite‐based catalysts for the purpose of 1) fundamental understanding of base‐catalysed processes with hydrotalcites and 2) optimisation of the catalytic performance achieved in reactions of industrial interest. Techniques based on probe molecules, titration techniques and test reactions along with physicochemical characterisation are overviewed in the first part of this review. The aim is to provide the tools for understanding how series of parameters involved in the preparation of hydrotalcite‐based catalytic materials can be employed to control and adapt the basic properties of the catalyst towards the basicity demanded by each target chemical reaction. An overview of recent and significant achievements in that perspective is presented in the second part of the paper.
Mental illness at work: An assessment of co‐worker reactions
Authors: Peters Heather , Brown Travor C.
Published: March 2009

Guided by Colella, Paetzold, and Belliveau (2004), we surveyed 305 employees on their reactions towards co‐workers with mental illness. Co‐workers were less likely to view longer/more frequent work breaks as appropriate accommodations for the mentally ill relative to flexible hours, banking of overtime hours, and counselling. Moreover, employees who believed that co‐workers with mental illness were being equitably (or fairly) treated at work were more likely to report that they would self‐disclose—and seek assistance for—a mental illness. Finally, employees with workplace contact with the mentally ill were more likely to support hiring people with mental illness. Copyright © 2009 ASAC. Published by John Wiley & Sons, Ltd.
CFD modeling of a prismatic spouted bed with two adjustable gas inlets
Authors: Gryczka Oliver , Heinrich Stefan , Deen Niels G. , van Sint Annaland Martin , Kuipers Johannes A.M. , Mörl Lothar
Published: March 2009

Since the invention of the spouted bed technology by Mathur and Gishler (1955), different kinds of apparatus design were developed and a huge number of applications in nearly all branches of industry have emerged. Modeling of spouted beds by means of modern simulation tools, like discrete particle models or continuum models, has become a precious opportunity to understand the complexity of multiphase flows in these apparatus. In this work, two‐dimensional continuum simulations of a novel kind of spouted bed apparatus with adjustable gas inlets are presented. Different gas–particle drag models are used to obtain a realistic flow structure. Simulated solid phase concentrations are compared with images taken during experiments. Furthermore, simulated and measured gas phase pressure fluctuations over the entire bed are contrasted allowing more accurate comparisons between the simulated and the real hydrodynamic behaviour of the spouted bed.
A discrete element study of wet particle–particle interaction during granulation in a spout fluidized bed
Authors: van Buijtenen Maureen S. , Deen Niels G. , Heinrich Stefan , Antonyuk Sergiy , Kuipers J. A. M.
Published: March 2009

In this article we study the effect of the inter‐particle interaction on the bed dynamics, by considering a variable restitution coefficient. The restitution coefficient is varied in time and space depending on the moisture content due to the particle–droplet interaction and evaporation. This study is done computationally, by using an extended discrete element model (DEM). The examined flow regimes comprise the intermediate/spout‐fluidization regime (B1), spouting‐with‐aeration regime (B2) and the jet‐in‐fluidized‐bed regime (B3). For all flow regimes, the averaged bed height increases with decreasing restitution coefficient. Moreover, the averaged bed height for a variable restitution coefficient is larger for all flow regimes compared to a case with a constant restitution coefficient, indicating that the distribution of the restitution coefficient influences the bed dynamics.

The effect of evaporation on the distribution of the restitution coefficient is only observed for the jet‐in‐fluidized‐bed regime (B3), where the background velocity is relatively high leading to enhanced evaporation from the particles in the annulus region. This is reflected in the averaged bed height for the evaporation test case, which is larger compared to a test case without evaporation.

A larger bed height for cases with variable restitution coefficient is due to the pressure build up in the spout region caused by the longer closing period of the spout channel. This is confirmed by the recorded pressure fluctuation signal and its root mean square which are larger for the cases with the variable restitution coefficient.
The Roles of Natriuretic Peptides in Pericardial Fluid in Patients with Heart Failure
Authors: Watanabe Masazumi , Kawaguchi Satoru , Nakahara Hideki , Hachimaru Tsuyoshi
Published: March 2009

Background

It is well known that the plasma concentrations of atrial and brain natriuretic peptides, as cardiac hormones, are elevated in heart failure.

Hypothesis

Pericardial fluid in patients with various heart diseases contains both natriuretic peptides that are released into the pericardial fluid. However, it is unknown whether these peptides reflect cardiac function in patients with various heart diseases, more than both the peptides in blood.

Methods

Plasma and pericardial fluid samples were obtained from 22 patients undergoing cardiac surgery for the measurement of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels in plasma and pericardial fluid.

Results

The ANP levels in pericardial fluid were higher in patients with impaired left ventricular systolic function (ejection fraction < 50% versus ≥ 50%; 77.0 ± 4.9 versus 14.0 ± 50.9, p = 0.017), but not BNP.

However, BNP levels in pericardial fluid were significantly higher in patients with left ventricle dilatation (left ventricular diastolic dimension ≤ 54 mm versus > 54 mm; 130.3 ± 68.9: 709.7 ± 324.7, p = 0.0168). Moreover, BNP levels in pericardial fluid were significantly higher in Grade III than Grade II and I (Grade I: echo‐free space < 5 mm, Grade II: 5–10 mm, Grade III: > 10 mm).

Conclusion

These results suggest that BNP levels in pericardial fluid served as more sensitive and accurate indicators of left ventricular diastolic dysfunction, and that increased BNP levels in pericardial fluid may have an important pathophysiologic role in heart failure as a cardiocyte‐derived antifibrotic factor. Copyright © 2009 Wiley Periodicals, Inc.
Prolonged Dual Antiplatelet Therapy Improves Clinical Outcomes in High‐risk Patients Implanted with Sirolimus‐eluting Stents
Authors: Dean Jia , Yujie Zhou , Yingxin Zhao , Yuyang Liu , Yonghe Guo , Wanjun Cheng , Zheng Cao
Published: March 2009

Background

Although a science advisory recommending 12 months of dual antiplatelet therapy after drug‐eluting stents implantation was published recently, the optimal duration of dual antiplatelet therapy has not yet been precisely determined.

Hypothesis

Prolonged dual antiplatelet therapy can improve clinical outcomes in high‐risk patients implanted with sirolimus‐eluting stents.

Methods

The patients implanted with sirolimus‐eluting stents were assigned into standard clopidogrel therapy group (clopidogrel 75 mg/d for 12 mo) and prolonged clopidogrel therapy group (clopidogrel 75 mg/d for 18 mo). Long‐term aspirin (100 mg/d) therapy was adopted in both groups. The primary endpoint was very late stent thrombosis.

Results

After 12 months, 24 patients were excluded because of major adverse cardiovascular events (MACEs). Three hundred and thirty six patients surviving without MACEs were further followed up for 6 months. Between 12 and 18 months, in 160 patients with standard clopidogrel therapy, 5.6% had very late stent thrombosis. In contrast, in 176 patients with prolonged clopidogrel therapy, 1.1% had very late stent thrombosis (p < 0.01, versus standard clopidogrel therapy group).

Conclusions

Prolonged dual antiplatelet therapy may be beneficial to prevent very late stent thrombosis after sirolimus‐eluting stents implantation in high‐risk patients. Copyright © 2009 Wiley Periodicals, Inc.
Cardiorespiratory Fitness and Sedentary Lifestyle in the Morbidly Obese
Authors: Vanhecke Thomas E. , Franklin Barry A. , Miller Wendy M. , deJong Adam T. , Coleman Catherine J. , McCullough Peter A.
Published: March 2009

Background

Sedentary lifestyles and poor physical fitness are major contributors to the current obesity and cardiovascular disease pandemic.

Hypothesis

Daily physical activity and cardiorespiratory fitness are correlated in morbidly obese individuals in their free‐living environment.

Methods

Ten morbidly obese participants continuously wore an activity sensor that measured caloric expenditure, minute‐by‐minute physical activity, and steps/day over a 72‐h period. Following collection of the device data, structured cardiorespiratory fitness testing was performed on each subject.

Results

Mean caloric expenditure for all individuals was 2,668 ± 481 kcal/d. On average, subjects took 3,763 ± 2,223 steps. On average 23 h and 51.6 min per d were spent sleeping or engaged in sedentary activity (<3 metabolic equivalents [METs]) and the remaining 8.4 min were spent in moderate activity (3–6 METs). Average peak VO2 was 16.8 ± 4.7 mL/kg/min. Higher peak VO2 correlated with higher total caloric expenditure (TCE; r = 0.628, p = 0.05) and trended with higher steps/day (r = 0.591, p = 0.07).

Conclusions

Most morbidly obese participants in this study were markedly sedentary. These study results may provide important links between obesity, poor fitness, and cardiovascular disease. Copyright © 2009 Wiley Periodicals, Inc.
Cytoskeleton rearrangements during Listeria infection: Clathrin and septins as new players in the game
Authors: Mostowy Serge , Cossart Pascale
Published: March 2009

The study of an infection process can reveal how microbes exploit the host, and can illuminate unknown host cellular functions. Invasive pathogens have evolved efficient strategies to promote their internalization within normally non‐phagocytic host cells. The so‐called “zippering” bacteria present to host cell receptors molecules that mimic endogenous ligands, thereby inducing specific intracellular signaling cascades ultimately resulting in actin polymerization and uptake. Here we review how the bacterial pathogen Listeria monocytogenes enters into cells, and present a series of studies revealing that in addition to actin rearrangements this bacterium exploits the clathrin‐mediated endocytosis machinery together with septins, a novel cytoskeleton element. The challenge is now to decipher how all of these components orchestrate themselves to permit entry into normally non‐phagocytic cells. Cell Motil. Cytoskeleton 2009. © 2009 Wiley‐Liss, Inc.
Design, Synthesis, and Evaluation of Carnosine Derivatives as Selective and Efficient Sequestering Agents of Cytotoxic Reactive Carbonyl Species
Authors: Vistoli Giulio , Orioli Marica , Pedretti Alessandro , Regazzoni Luca , Canevotti Renato , Negrisoli Gianpaolo , Carini Marina , Aldini Giancarlo
Published: March 2009

Carnosine aryl derivatives as sequestering agents of RCS: Reactive carbonyl species (RCS) are cytotoxic mediators representing a novel drug target, as they are presumed to play a pathogenic role in several diseases. Carnosine is a selective RCS‐sequestering agent, but is rapidly hydrolyzed by serum carnosinase. Herein we describe the in silico design, synthesis, and evaluation of a set of carnosine aryl derivatives.

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Reactive carbonyl species (RCS) are important cytotoxic mediators generated by lipid oxidation of polyunsaturated fatty acids (PUFAs) and represent a novel drug target, as they are presumed to play a pathogenic role in several diseases. L‐Carnosine (L‐CAR, β‐alanyl‐L‐histidine) is a specific detoxifying agent of RCS, but is rapidly hydrolyzed in human serum by carnosinase, a specific dipeptidase. Herein we describe the in silico design, synthesis, and biological evaluation of carnosine derivatives that are resistant to carnosinase and that have increased quenching efficacy. Stability against carnosinase‐mediated turnover was achieved by isomerization of the histidine residue, leading to D‐carnosine (D‐CAR, β‐alanyl‐D‐histidine), which maintains the same quenching activity of L‐carnosine. A molecular modeling approach was then used to design derivatives characterized by an increased quenching efficacy. The most promising candidates were synthesized, and their stability and quenching activity were evaluated. This study describes a set of aryl derivatives that are characterized by high stability in human plasma and a quenching activity toward 4‐hydroxy‐trans‐2‐nonenal (HNE), chosen as a model of RCS, up to threefold greater than D‐carnosine.
Understanding chemical shielding tensors using group theory, MO analysis, and modern density‐functional theory
Authors: Widdifield Cory M. , Schurko Robert W.
Published: March 2009

In this article, the relationships between molecular symmetry, molecular electronic structure, and chemical shielding (CS) tensors are discussed. First, a brief background on the CS interaction and CS tensors is given. Then, the visualization of the three‐dimensional nature of CS is described. A simple method for examining the relationship between molecular orbitals (MOs) and CS tensors, using point groups and direct products of irreducible representations of MOs and rotational operators, is outlined. A number of specific examples are discussed, involving CS tensors of different nuclei in molecules of different symmetries, including ethene (D2h), hydrogen fluoride (C∞v), trifluorophosphine (C3v), and water (C2v). Finally, we review the application of this method to CS tensors in several interesting cases previously discussed in the literature, including acetylene (D∞h), the PtX42− series of compounds (D4h) and the decamethylaluminocenium cation (D5d). © 2009 Wiley Periodicals, Inc. Concepts Magn Reson Part A 34A: 91–123, 2009.
Racial differences in medical mistrust among men diagnosed with prostate cancer
Authors: Halbert Chanita Hughes , Weathers Benita , Delmoor Ernestine , Mahler Brandon , Coyne James , Thompson Hayley S. , Have Thomas Ten , Vaughn David , Malkowicz S. Bruce , Lee David
Published: March 2009

BACKGROUND:

Mistrust of healthcare providers and systems is a significant barrier to quality healthcare. However, limited empirical data are available on perceptions of medical mistrust among individuals who are diagnosed with cancer. The objective of this study was to identify sociodemographic, clinical, and cultural determinants of mistrust among men diagnosed with prostate cancer.

METHODS:

The authors conducted an observational study among 196 African‐American men (n = 71) and white men (n = 125) who were newly diagnosed with prostate cancer during 2003 through 2007.

RESULTS:

Race, education, healthcare experiences, and cultural factors had significant effects on mistrust. African‐American men (P = .01) and men who had fewer years of formal education (P = .001) reported significantly greater levels of mistrust compared with white men and men who had more education. Mistrust also was greater among men who had been seeing their healthcare provider for a longer period (P = .01) and among men with lower perceptions of interdependence (P = .01).

CONCLUSIONS:

The current findings suggested that efforts to enhance trust among men who are diagnosed with prostate cancer should target African‐American men, men with fewer socioeconomic resources, and men with lower perceptions of interdependence. Reasons for deterioration in trust associated with greater experience with specialty providers should be explored along with the effects of interventions that are designed to address the concerns of individuals who have greater mistrust. Cancer 2009. © 2009 American Cancer Society.
Genetic polymorphism in chemokine CCL22 and susceptibility to Helicobacter pylori infection‐related gastric carcinoma
Authors: Wang Guanghai , Yu Dianke , Tan Wen , Zhao Dan , Wu Chen , Lin Dongxin
Published: March 2009

BACKGROUND:

Gastric carcinoma is widely considered to be related to Helicobacter pylori infection, and the chemokine (C‐C motif) ligand 22 (CCL22) plays an important role in suppressing immune responses against H. pylori and tumor cells. In this study, the authors examined the association between single nucleotide polymorphisms (SNPs) in the CCL22 gene and the risk of gastric carcinoma.

METHODS:

Information on SNPs in the CCL22 coding region was obtained from the HapMap Project database. Genotypes were determined in a case‐control cohort that consisted of 1001 patients with gastric carcinoma and 1066 controls, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were computed by using a logistic regression model. Serum H. pylori antibody levels were measured by using an enzyme‐linked immunosorbent assay.

RESULTS:

The 16C→A SNP (reference SNP no. 4359426) in exon 1 of the CCL22 gene, which causes a 2 aspartate (2Asp) to 2 alanine (2Ala) substitution in the CCL22 protein, was associated with a significantly increased risk of gastric carcinoma. Individuals who were homozygous for the Ala/Ala genotype had an OR of 2.27 (95% CI, 1.28‐4.02) compared with individuals who had the Asp/Asp genotype. Stratification analysis indicated that the association was more pronounced among men (OR, 2.64; 95% CI, 1.29‐5.41) and among younger individuals (OR, 2.85; 95% CI, 1.36‐5.96) compared with women and older individuals. Moreover, a multiplicative joint effect between the CCL22 SNP and H. pylori infection that intensified the risk was observed (OR for the presence of both Ala/Ala genotype and H. pylori infection, 18.37; 95% CI, 2.30‐146.67).

CONCLUSIONS:

The results from this study suggested that the CCL22 polymorphism is associated with an increase risk of developing H. pylori infection‐related gastric carcinoma. Cancer 2009. © 2009 American Cancer Society.
Development and evaluation of BioScore
Authors: Parker Alexander S. , Leibovich Bradley C. , Lohse Christine M. , Sheinin Yuri , Kuntz Susan M. , Eckel‐Passow Jeanette E. , Blute Michael L. , Kwon Eugene D.
Published: March 2009

BACKGROUND:

The authors previously showed that increased tumor expression levels of B7‐H1, survivin, and Ki‐67 are independent predictors of poor outcome for patients with clear cell renal cell carcinoma (ccRCC). In the current study, they described the creation of a scoring system based on this panel of biomarkers that can be used in tandem with existing clinicopathologic features and algorithms to improve ccRCC outcome prediction.

METHODS:

The authors used immunohistochemistry to determine tumor expression levels of B7‐H1, survivin, and Ki‐67 for 634 consecutive ccRCC patients. A multivariate model verified that each biomarker was independently associated with RCC‐specific death after adjusting for the remaining 2. A biomarker‐based panel, termed BioScore, was generated to predict the likelihood of RCC‐specific death. BioScore was tested for its ability to enhance the performance of several clinicopathologic features and algorithms.

RESULTS:

Patients with high BioScores were 5 times more likely to die from RCC compared with patients with low BioScores (hazard ratio, 5.03; 95% confidence interval, 3.82‐6.61; P < .001). Multivariate adjustment for individual clinicopathologic features or existing prognostic algorithms failed to attenuate this positive association. Moreover, an examination of concordance indexes revealed that BioScore significantly enhanced the prognostic ability of each of the individual prognostic features or algorithms studied.

CONCLUSIONS:

The authors described the creation of BioScore, a biomarker‐based scoring system that can be used in tandem with established prognostic algorithms to further enhance ccRCC outcome prediction. The need for external validation notwithstanding, they envision that BioScore can be readily updated as new biomarkers are identified. Cancer 2009. © 2009 American Cancer Society.
Benefit of postoperative adjuvant therapy for pancreatic cancer
Authors: Vanderveen Kimberly A. , Chen Steven L. , Yin Daixin , Cress Rosemary D. , Bold Richard J.
Published: March 2009

BACKGROUND:

Despite the recent completion of several trials of adjuvant therapy after resection for pancreatic adenocarcinoma, the absolute impact on survival and the identification of appropriate patients for treatment has remained controversial. In the current study, the authors sought to identify the impact of adjuvant therapy and factors associated with any improvement in survival after resection of pancreatic cancer.

METHODS:

Through the California Cancer Registry, all California residents diagnosed with pancreatic cancer between 1994 and 2002 were identified. Factors potentially impacting survival were analyzed, including patient demographics, tumor characteristics, and treatment provided. Univariate and multivariate survival analyses were performed by Kaplan‐Meier and Cox regression methods.

RESULTS:

A total of 26,518 patients were identified; 3196 (12.1%) underwent resection as their primary treatment. The median overall survival was 16 months for patients who underwent resection. Prognostic factors associated with better survival included negative lymph node status, well‐differentiated tumors, younger age, female sex, and the receipt of any adjuvant therapy. On multivariate analysis, adjuvant therapy demonstrated a statistically significant, although modest, impact on survival, with a hazards ratio of 0.79 (95% confidence interval, 0.72‐0.87; P < .001). The benefit of adjuvant therapy was only apparent in those patients with lymph node–positive or poorly differentiated tumors.

CONCLUSIONS:

Adjuvant therapy provided for a modest improvement in overall survival after surgical resection of pancreatic cancer. The absolute effect was most pronounced in those patients with poor prognostic indicators. To identify effective systemic therapy for this deadly cancer, future clinical trials of adjuvant therapy should focus on these groups of patients. Cancer 2009. © 2009 American Cancer Society.
Spatial representations of odorants in olfactory bulbs of rats and mice: Similarities and differences in chemotopic organization
Authors: Johnson Brett A. , Xu Zhe , Ali Sameera S. , Leon Michael
Published: March 2009

In previous studies, we mapped glomerular layer 2‐deoxyglucose uptake evoked by hundreds of both systematically related and chemically distinct odorants in rat olfactory bulbs. To determine which principles of chemotopic organization revealed in these studies may be more fundamental and which may be more species typical, we now have characterized patterns of responses to 30 of these odorants in mice. We found that only a few odorants evoked their multiple foci of peak activity in exactly the same locations in the two species. In mice, as in rats, odorants that shared molecular features evoked overlapping patterns, but the locations of the feature‐responsive domains often differed in rats and mice. In rats, increasing carbon number within a homologous series of aliphatic odorants is generally associated with rostral and ventral progressions of activity within domains responding to odorant functional group and/or hydrocarbon backbone. Such chemotopic progressions were not obvious in mice, which instead showed more abrupt differences in activated glomeruli within the domains for odorants differing by a single methylene group. Despite the differences, quantitative relationships between overall uptake patterns exhibited a similar organization with respect to odorant chemistry for the two species, probably as a result of partial overlaps of peak domains and more extensive overlaps in large, low‐activity areas for rats and mice. We conclude that clustering responses to shared odorant features may be a general strategy for odor coding but that the specific locations of high‐activity domains may be unique to a species. J. Comp. Neurol. 514:658–673, 2009. © 2009 Wiley‐Liss, Inc.
Spectroscopic Investigation of the Ultrafast Photoinduced Dynamics in π‐Conjugated Terpyridines
Authors: Siebert Ronald , Akimov Denis , Schmitt Michael , Winter Andreas , Schubert Ulrich S. , Dietzek Benjamin , Popp Jürgen
Published: March 2009

Ultrafast light‐induced processes in a series of π‐conjugated mono‐, bis‐, tris‐ and tetrakis(terpyridine) derivatives are investigated by femtosecond time‐resolved spectroscopy. Non‐exponential excited‐state dynamics involving singlet–triplet intersystem crossing are observed which span from picoseconds to nanoseconds (see figure).

magnified image

Time‐resolved spectroscopy is applied to investigate the ultrafast relaxation dynamics of several π‐conjugated mono‐, bis‐, tris‐ and tetrakis(terpyridine) derivatives. This particular series of structurally closely related systems was prepared applying efficient synthetic strategies and resembles key building blocks for a wide range of photoactive complexes, dendrimers and metallo‐polymers with resulting potential applications, for example, in photovoltaics or as organic light‐emitting diodes. Aiming for applications of supramolecular assemblies based on these recently presented terpyridine ligands a detailed knowledge of the light‐induced processes of the ligands themselves represents a prerequisite. By applying femtosecond time‐resolved absorption spectroscopy in concert with time‐resolved fluorescence and Raman measurements, we detail the photophysical properties.
Effusion cytomorphology and immunocytochemistry of malignant melanoma: Five cases of melanotic melanoma and one case of amelanotic melanoma
Authors: Ikeda Katsuhide , Tate Genshu , Iezumi Keiichi , Suzuki Takao , Kitamura Takashi , Mitsuya Toshiyuki
Published: March 2009

Effusion cytological analyses of amelanotic malignant melanoma (AMM) are very rare and no concise description of AMM related cytomorphologic features using effusion have been reported. Here, we report the cytomorphological, immunohistochemical, and immunocytochemical findings in the effusion cytology of six cases of malignant melanoma (MM), one case of AMM, and five cases of melanotic malignant melanoma.

Papanicolaou‐stained smears exhibited conspicuous nucleoli, multinucleation, and cytoplasmic vacuolization in all of the MM cases. In addition, the AMM case displayed numerous mitotic figures and intranuclear cytoplasmic inclusions. With regard to the immunohistochemistry findings, all six cases of melanoma were positive for Melan‐A/MART‐1, HBME‐1, and S‐100. In the immunohistochemistry analyses, five of six cases of melanoma were positive for WT‐1, as was the AMM specimen. Furthermore, because the effusion analysis of malignant mesothelioma proved positive for WT‐1, it should be noted that WT‐1 effusion analysis is not an appropriate means to distinguish between MM and malignant mesothelioma.

We suggest that it is important to recognize cytomorphologic characteristics, such as melanin pigment, conspicuous nucleoli, multinucleation, and cytoplasmic vacuolization, and to choose appropriate antibodies for the correct diagnosis of MM in effusion. Diagn. Cytopathol., 2009. © 2009 Wiley‐Liss, Inc.