bluuebunny/crossref_metadata_2025 huggingface dataset:
Nucleophilic Reactivities of Pyrroles (Eur. J. Org. Chem. 14/2008)
Authors: Nigst Tobias A. , Westermaier Martin , Ofial Armin R. , Mayr Herbert
Published: April 2008

The cover picture is misleading! With the determination of the nucleophilic reactivities of pyrroles, our electrophilicity‐nucleophilicity puzzle, where synthetically useful reactions are found in the green corridor (see: R. Lucius, R. Loos, H. Mayr, Angew. Chem. Int. Ed. 2002, 41, 91–95), is not yet complete. The picture illustrates, however, that the reactions of pyrroles with electrophiles also follow the linear free‐energy relationship log k20°C = s(N + E), where N and s characterize the reactivities of nucleophiles and E describes the reactivities of electrophiles. Alkyl substitution increases the nucleophilicity of pyrrole by a factor of up to 10 million, and from the nucleophilicity parameters reported in this article by H. Mayr et al. on p. 2369 ff, one can derive suitable electrophilic reaction partners for alkyl‐substituted pyrroles.
Fabrication of 3‐D gel microarrays directly with raw polymerase chain reaction products by heat‐directed polymerization
Authors: Pan Zhiqiang , Li Yanqiang , Shan Qun , Hong Xiaohong , Zhou Dongrui , Zhang Minghao , Chen Ping , Xiao Pengfeng , Lu Zuhong
Published: April 2008

In this study, a new method for fabricating 3‐D polyacrylamide gel microarrays was presented. In the method, a 3‐D gel microarray was successfully fabricated by directly heating the slides with arrayed prepolymer at 80°C for 2 min. The prepolymer on the microarray only contained 40% v/v raw/unpurified PCR products, 1.4% ammonium persulfate (APS), 6% acrylamide, and 20% glycerol and the balance H2O but no TEMED. The heat could induce the free radicals from APS to initiate polymerization of the 3‐D gel and allow the incorporation of raw PCR products into the 3‐D gel. The immobilized DNA on the gel microarray had the specificity of hybridization and the ability to distinguish base mismatch. It has been demonstrated that SNP genotyping of both the 194072 loci and the 252944 loci in the β2 subunit gene of γ‐aminobutyric acid A receptor (GABRB2) gene was successfully performed by using the 3‐D gel microarray. This method is efficient, simple, rapid, and easy to control in preparing a 3‐D gel microarray, which would be widely used for various purposes in laboratory research and clinic application.
Exonuclease activity of proofreading DNA polymerases is at the origin of artifacts in molecular profiling studies
Authors: Gury Jerome , Zinger Lucie , Gielly Ludovic , Taberlet Pierre , Geremia Roberto A.
Published: April 2008

CE fingerprint methods are commonly used in microbial ecology. We have previously noticed that the position and number of peaks in CE‐SSCP (single‐strand conformation polymorphism) profiles depend on the DNA polymerase used in PCR [1]. Here, we studied the fragments produced by Taq polymerase as well as four commercially available proofreading polymerases, using the V3 region of the Escherichia coli rss gene as a marker. PCR products rendered multiple peaks in denaturing CE; Taq polymerase was observed to produce the longest fragments. Incubation of the fragments with T4 DNA polymerase indicated that the 3′‐ends of the proofreading polymerase amplicons were recessed, while the Taq amplicon was partially +A tailed. Treatment of the PCR product with proofreading DNA polymerase rendered trimmed fragments. This was due to the 3′–5′ exonuclease activity of these enzymes, which is essential for proofreading. The nuclease activity was reduced by increasing the concentration of dNTP. The Platinum® Pfx DNA polymerase generated very few artifacts and could produce 85% of blunted PCR products. Nevertheless, despite the higher error rate, we recommend the use of Taq polymerase rather than proofreading in the framework for molecular fingerprint studies. They are more cost‐effective and therefore ideally suited for high‐throughput analysis; the +A tail artifact rate can be controlled by modifying the PCR primers and the reaction conditions.
High frequency stream bed mobility of a low‐gradient agricultural stream with implications on the hyporheic zone
Authors: Peterson Eric W. , Sickbert Timothy B. , Moore Suzanna L.
Published: April 2008

Little Kickapoo Creek (LKC), a low‐gradient stream, mobilizes its streambed–fundamentally altering its near‐surface hyporheic zone–more frequently than do higher‐gradient mountain and karst streams. LKC streambed mobility was assessed through streambed surveys, sediment sampling, and theoretical calculations comparing basal shear stress (τb) with critical shear stress (τc). Baseflow τb is capable of entraining a d50 particle; bankfull flow could entrain a 51·2 mm particle. No particle that large occurs in the top 30 cm of the substrate, suggesting that the top 30 cm of the substrate is mobilized and redistributed during bankfull events. Bankfull events occur on average every 7·6 months; flows capable of entraining d50 and d85 particles occur on average every 0·85 and 2·1 months, respectively. Streambed surveys verify streambed mobility at conditions below bankfull. While higher gradient streams have higher potential energy than LKC, they achieve streambed‐mobilization thresholds less frequently. Heterogeneous sediment redistribution creates an environment where substrate hydraulic conductivity (K) varies over four orders of magnitude. The frequency and magnitude of the substrate entrainment has implications on hyporheic zone function in fluid, solute and thermal transport models, interpretations of hyporheic zone stability, and understanding of LKC's aquatic ecosystem. Copyright © 2008 John Wiley & Sons, Ltd.
Retracted: Genistein mediated histone acetylation and demethylation activates tumor suppressor genes in prostate cancer cells
Authors: Kikuno Nobuyuki , Shiina Hiroaki , Urakami Shinji , Kawamoto Ken , Hirata Hiroshi , Tanaka Yuichiro , Majid Shahana , Igawa Mikio , Dahiya Rajvir
Published: April 2008

The above article, published online on 22 April 2008 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, Prof. Peter Lichter, and John Wiley & Sons Ltd. The retraction has been agreed due to errors identified in Figs, 3, 4, and 5. The concerns about these figures cannot be resolved because the original data can no longer be retrieved.

Reference

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SU‐8 2000 rendered cytocompatible for neuronal bioMEMS applications
Authors: Vernekar Varadraj N. , Cullen D. Kacy , Fogleman Nick , Choi Yoonsu , García Andrés J. , Allen Mark G. , Brewer Gregory J. , LaPlaca Michelle C.
Published: April 2008

Microfabrication advances have resulted in small, cheap, and precise devices for biological microelectromechanical systems (bioMEMS). SU‐8/SU‐8 2000 is an attractive material for these applications because of its high‐aspect ratio fabrication capability, dielectric properties, and thermochemical stability. Despite these advantages, the potential toxicity of SU‐8 2000 may limit its use in cell‐based applications. We show that <10% of primary neurons survived when cultured adjacent to or on top of untreated SU‐8 2000. We evaluated the efficacy of various detoxification and surface treatments for SU‐8 2000 in neuronal cultures after 7–21 days in vitro. Viability was improved to 45.8% ± 4.5% (mean ± standard error of the mean) following 3‐day heat treatment (150°C) under vacuum, while UV exposure and CO2 supercritical extraction did not improve survival. Furthermore, parylene coating (25 μm), in combination with heat and sonication (in isopropanol) treatments effectively masked the SU‐8 2000 and led to 86.4% ± 1.9% viability. Glow discharge (oxygen plasma) treatment rendered the SU‐8 2000 surface more hydrophilic and improved neuronal viability, possibly through improved cell adhesion. No organic leachants were detected by mass spectrometry before or after heat treatment or after sonication. However, XPS analysis revealed the presence of potentially neurotoxic elements, fluorine and antimony. Strategies to improve the cytocompatibility of SU‐8 2000 with primary neurons will allow longer culture times and have applications for cell‐based microfabrication. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Fabrication of free‐standing albumin‐nanosheets having heterosurfaces
Authors: Okamura Yosuke , Goto Takahiro , Niwa Daisuke , Fukui Yoshihito , Otsuka Masanobu , Motohashi Norikazu , Osaka Tetsuya , Takeoka Shinji
Published: April 2008

Sheet‐shaped carriers, having both obverse and reverse surfaces and thus a large contact area for targeting a site, have several advantages over spherical‐shaped carriers, which have an extremely small contact area for targeting sites. Here, we proposed a novel method to prepare a free‐standing ultrathin and biocompatible nanosheet having heterosurfaces, by a combination of four processes: (1) specific adsorption of recombinant human serum albumin (rHSA) molecules onto a patterned octadecyltrimethoxysilane self‐assembled monolayer region (ODS‐SAM), (2) preparation of nanosheets of rHSA molecules bearing thiol groups (SH‐rHSA) via two‐dimensionally disulfide crosslinking, (3) surface modification of the resulting nanosheet, and (4) preparation of the free‐standing nanosheet by detachment from the ODS‐SAM. The SH‐rHSA molecules at pH 5.0 and a concentration of 1 μg/mL were specifically adsorbed on the patterned ODS‐SAM regions by hydrophobic interaction, and were two‐dimensionally crosslinked in the presence of copper ion as an oxidant. The rHSA‐nanosheets were then simply detached from the ODS‐SAM by treatment with surfactant. We succeeded in the preparation of rectangular (10 μm × 30 μm) and ultrathin (4.5 ± 1.0 nm) rHSA‐nanosheets on a patterned ODS‐SAM, and could also obtain free‐standing rHSA‐nanosheets having heterosurfaces by surface modification with fluorescent latex beads. Thus, the rHSA‐nanosheets having heterosurfaces could be regarded as a new biomaterial for drug carriers, hemostatic reagents, wound dressing for burn injury, and so forth. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Material properties and bone marrow stromal cells response to In situ crosslinkable RGD‐functionlized lactide‐co‐glycolide scaffolds
Authors: Jabbari Esmaiel , He Xuezhong , Valarmathi Mani T. , Sarvestani Alireza S. , Xu Weijie
Published: April 2008

In situ crosslinkable biomaterials with degradation profiles that can be tailored to a particular application are indispensable for treating irregularly shaped defects and for fabrication of shape‐selective scaffolds. The objective of this work was to synthesize ultra low molecular weight functionalized PLA and PLGA macromers that can be grafted with bioactive peptides and crosslinked in situ to fabricate biodegradable functional scaffolds. In situ crosslinkable lactide‐co‐glycolide macromer (cMLGA; “c” for crosslinkable, “M” for macromer, and “LGA” for lactide‐co‐glycolide) was synthesized by anionic polymerization of lactide and glycolide monomers followed by condensation polymerization with fumaryl chloride. The cMLA (100% L‐lactide) and cMLGA macromers formed porous crosslinked scaffolds with NVP as the crosslinker. The mass loss of the crosslinked cMLA and cMLGA was linear with incubation time in vitro (zero‐order degradation) and the degradation rate depended on the ratio of lactide to glycolide. cMLGA scaffold with 1:1 lactide to glycolide ratio completely degraded after 4 weeks while the cMLA lost less than 40% of its initial mass after 35 weeks. When cMLA scaffold was functionalized with acrylated integrin‐binding Ac‐GRGD amino acid sequence, bone marrow stromal (BMS) cells attached and spread on the cMLA scaffold and exhibited focal‐point cell adhesion. The mRNA expression levels of collagen‐1α, osteonectin, and osteopontin for BMS cells seeded in the scaffolds with 1 and 5% Ac‐GRGD were upregulated compared with those without Ac‐GRGD. cMLGA is attractive as in situ crosslinkable macromer for fabrication of functional scaffolds with degradation characteristics that can be tailored to a particular application. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
The effect of dehydrothermal treatment on the mechanical and structural properties of collagen‐GAG scaffolds
Authors: Haugh Matthew G. , Jaasma Michael J. , O'Brien Fergal J.
Published: April 2008

The mechanical properties of tissue engineering scaffolds are critical for preserving the structural integrity and functionality during both in vivo implantation and long‐term performance. In addition, the mechanical and structural properties of the scaffold can direct cellular activity within a tissue‐engineered construct. In this context, the aim of this study was to investigate the effects of dehydrothermal (DHT) treatment on the mechanical and structural properties of collagen‐glycosaminoglycan (CG) scaffolds. Temperature (105–180°C) and exposure period (24–120 h) of DHT treatment were varied to determine their effect on the mechanical properties, crosslinking density, and denaturation of CG scaffolds. As expected, increasing the temperature and duration of DHT treatment resulted in an increase in the mechanical properties. Compressive properties increased up to twofold, while tensile properties increased up to 3.8‐fold. Crosslink density was found to increase with DHT temperature but not exposure period. Denaturation also increased with DHT temperature and exposure period, ranging from 25% to 60% denaturation. Crosslink density was found to be correlated with compressive modulus, whilst denaturation was found to correlate with tensile modulus. Taken together, these results indicate that DHT treatment is a viable technique for altering the mechanical properties of CG scaffolds. The enhanced mechanical properties of DHT‐treated CG scaffolds improve their suitability for use both in vitro and in vivo. In addition, this work facilitates the investigation of the effects of mechanical properties and denaturation on cell activity in a 3D environment. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Efficacy of a p38 mitogen activated protein kinase inhibitor in mitigating an established inflammatory reaction to polyethylene particles in vivo
Authors: Ma T. , Ren P.‐G. , Larsen D. M. , Suenaga E. , Zilber S. , Genovese M. , Smith R. L. , Goodman S. B.
Published: April 2008

The inhibitor of p38 mitogen‐activated protein kinase (MAPK) is of interest in the nonoperative treatment of periprosthetic osteolysis due to wear particles. Previous studies demonstrated that an oral p38 MAPK inhibitor did not suppress bone formation when given during the initial phase of tissue differentiation. However, the oral p38 MAPK inhibitor also did not curtail the foreign body and chronic inflammatory response to particles when given simultaneously. The purpose of the current study was to examine the efficacy of a p38 MAPK inhibitor, SCIO‐323, on mitigating an established inflammatory reaction that parallels the clinical situation more closely. The Bone Harvest Chamber was implanted in rabbits and submicron polyethylene particles were placed in the chamber for 6 weeks. The contents of the chambers were harvested every 6 weeks. Oral treatment with the SCIO‐323 included delivery for 3 weeks and stopping for 3 weeks, delivery for 3 weeks after an initial 3‐week delay, and delivery for 6 weeks continuously. Administration of the SCIO‐323 continuously for 6 weeks with/without the presence of particles, or for the initial 3 of 6 weeks had minor effects on bone ingrowth. After establishing a particle‐induced chronic inflammatory reaction for 3 weeks, administration of SCIO‐323 for a subsequent 3 weeks suppressed net bone formation. The activity of osteoclast‐like cells remained low among all treatments when compared with the first control. Using the present model, the oral p38 MAPK inhibitor was ineffective in improving bone ingrowth in the presence of polyethylene particles. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Doubly stochastic Poisson distribution of platelet adhesion on material surfaces and its implication on fluorescence image analysis
Authors: Pang Zhengyu , Cawse James N. , Yu Liming , Richards William D.
Published: April 2008

An image based assay has been developed to quantify platelet adhesion on material surfaces. Briefly, citrated platelet rich plasma (PRP) is incubated with materials for 2 h to allow platelet adhesion on the surface, followed by fluorescence labeling of platelets with Celltracker Green™. Multiple images are acquired by an automatic fluorescence microscope, IN Cell Analyzer 1000™. Platelets are identified and counted by an automatic image analysis algorithm. We have observed that the variance of the counts is considerably greater than expected from simple distribution laws. Statistical analysis of that difference shows that these measurements will often follow a doubly stochastic Poisson process in which the variance is inherently very large. To overcome this, multiple images (n ≥ 8 images/well, about 3% of total area) are necessary to achieve accurate counting. This method has been compared to the commonly used enzyme based platelet adhesion assay, lactate dehydrogenase (LDH) assay. It is concluded that the present method is only effective in quantifying adherent platelets when a large number of samples are used. However, this method does provide additional information on platelet morphology and spatial distribution, which is lacking in the LDH assay. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Evaluation of antitubercular drug‐loaded surfactants as inhalable drug‐delivery systems for pulmonary tuberculosis
Authors: Chimote G. , Banerjee R.
Published: April 2008

Pulmonary tuberculosis is associated with a year‐long chemotherapy, poor alveolar drug levels, drug‐related systemic toxicity, and patient noncompliance. In this study, exogenous pulmonary surfactant is proposed as a drug carrier for antitubercular drugs. Dipalmitoylphosphatidylcholine (DPPC), the major lung‐surfactant lipid, has been combined with antitubercular drugs isoniazid (INH), rifampicin (RFM), and ethambutol (ETH) in 1:1 ratio by weight, in which drugs had a ratio of 1:2:3 by weight. At 37°C, the formulation had better surfactant function with quicker reduction of surface tension on adsorption (32.71 ± 0.65 mN/m) than DPPC liposomes (44.67 ± 0.57 mN/m) and maintained 100% airway patency in a capillary surfactometer. Drug‐loaded surfactant liposomes were about 2 μm and had entrapment efficiency of 30.04% ± 2.05%, 18.85% ± 2.92%, and 61.47% ± 3.32% for INH, RFM, and ETH, respectively. Sustained release of the drugs from surfactants was observed over 24 h. In vitro alveolar deposition efficiency using the twin impinger showed 12.06% ± 1.87% of INH, 43.30% ± 0.87% of RFM, and 22.07% ± 2.02% of ETH deposited in the alveolar chamber upon nebulization for a minute using a jet nebulizer. The formulation was biocompatible and stable with physicochemical properties being retained even after storage for a month at 4°C. Antitubercular drug‐loaded surfactants developed could serve dual purposes of alveolar stabilization due to surfactant action and better reach of these drugs to the alveoli due to antiatelectatic effect of the surfactant. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Immobilization of urease by laser techniques: Synthesis and application to urea biosensors
Authors: György E. , Sima F. , Mihailescu I. N. , Smausz T. , Megyeri G. , Kékesi R. , Hopp B. , Zdrentu L. , Petrescu S. M.
Published: April 2008

Urease thin films have been immobilized using matrix‐assisted pulsed laser evaporation for biosensor applications in clinical diagnostics. The targets exposed to laser radiation were made of frozen composites that had been manufactured by dissolving urease in distilled water. An UV KrF* (λ = 248 nm, τFWHM ≅ 30 ns, ν = 10 Hz) excimer source was used for the multipulse laser irradiation of the targets that were cooled down to solidification using Peltier elements. The incident laser fluence was set at 0.4 J/cm2. The surface morphology and chemical bonding states of the laser immobilized urease thin films were investigated by atomic force microscopy and Fourier transform infrared spectroscopy. The enzymatic activity and kinetics of the immobilized urease were assayed by the Worthington method, which monitors urea hydrolysis by coupling ammonia production to a glutamate dehydrogenase reaction. Decreased absorbance was found at 340 nm and correlated with the enzymatic activity of urease. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Electrospinning of multicomponent ultrathin fibrous nonwovens for semi‐occlusive wound dressings
Authors: Hong Youliang , Li Yanan , Zhuang Xiuli , Chen Xuesi , Jing Xiabin
Published: April 2008

This work describes the design and assembly of multifunctional and cost‐efficient composite fiber nonwovens as semi‐occlusive wound dressings using a simple electrospinning process to incorporate a variety of functional components into an ultrathin fiber. These components include non‐hydrophilic poly(L‐lactide) (PLLA) as fibrous backbone, hydrophilic poly(vinyl pyrrolidone)–iodine (PVP–I), TiO2 nanoparticles, zinc chloride as antimicrobial, odor‐controlling, and antiphlogistic agents, respectively. The process of synthesis starts with a multicomponent solution of PLLA, PVP, TiO2 nanoparticles plus zinc chloride, in which TiO2 nanoparticles are synthesized by in situ hydrolysis of TiO2 precursors in a PVP solution for the sake of obtaining the particle‐uniformly dispersive solution. Subsequent electrospinning generates the corresponding composite fibers. A further iodine vapor treatment to the composite fibers combines iodine with PVP to produce the PVP–I complexes. Experiments indicate that the assembled composite fibers (300–400 nm) possess the ointment‐releasing characteristic and the phase‐separate, core‐sheath structures in which PVP–I residing in fiber surface layer becomes the sheath, and PLLA distributing inside the fiber acts as the core. Based on this design, the structural advantages combining active components endow the assembled composite nonwovens with a variety of functions, especially, the existence of PVP–I, endows the nonwoven with water absorbability, antimicrobial activity, adhesive ability, and transformable characteristic from hydrophilicity to non‐hydrophilicity. The multifunctional, cost‐efficient, and ointment‐releasing characteristics make the multicomponent composite fibrous nonwovens potentially useful in applications such as initial stage of dressing of the cankerous or contaminated wounds. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Energy consumption as a predictor test of the durability of a biological tissue employed in cardiac bioprosthesis
Authors: García Páez J. M. , Claramunt R. , Jorge Herrero E. , Millan I. , Tolmos J. R. , Álvarez L. , Cordon A. , Rocha A. , Sanz P. , Ayuso B. , Ros A.
Published: April 2008

The mechanical behavior of the young bull pericardium in a fatigue test has been studied. This material is a similar tissue to those used in valve leaflet construction for a cardiac bioprosthesis. The consumed energy on each test was evaluated and afterwards used as a predictor of the biomaterial strength. Two‐hundred and nine samples were tested to cyclical fatigue. The cut‐off point to determine the sample quality was whether or not they resisted at least 4500 cycles. Only 22 samples withstood over that point (10.52%). The samples were classified according to their fatigue behavior in excellent, undefined and unsuitable. By using as a reference the consumed energy in the first 25 cycles, we could distinguish correctly (between 93.2 and 96.1%) the unsuitable material and most of the excellent (between 78.1 and 95.2%). From the rejected material 77% was really detachable and from the accepted, only 50% was excellent, with an equal methodology. The receiver operating characteristics curve was employed to establish decision levels when selecting samples, being 0.85 the best area (theoretical maximum value of 1). It is concluded that the energy wasted is a good predictor of the strength of the tissue. More than 90% of the unsuitable material and 50% of the excellent material (5% of all the material) is detected with this method. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
The behavior of MC3T3‐E1 cells on chitosan/poly‐L‐lysine composite films: Effect of nanotopography, surface chemistry, and wettability
Authors: Zheng Zhenhuan , Zhang Ling , Kong Lijun , Wang Aijun , Gong Yandao , Zhang Xiufang
Published: April 2008

In the present work, a series of composite films were produced from chitosan/poly‐L‐lysine blend solutions. The surface topography, chemistry, and wettability of composite films were characterized by atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy, and contact angle assay, respectively. For all composite films, blending with poly‐L‐lysine induced changes in surface chemistry and wettability. Interestingly, it was also found that increasing poly‐L‐lysine weight fraction in blend solutions could result in different nanoscaled surface topographic features, which displayed particle‐, granule‐, or fiber‐dominant morphologies. MC3T3‐E1 osteoblast‐like cells were cultured on all composite films to evaluate the effects of surface nanotopography, chemistry, and wettability on cell behavior. The observations indicated that MC3T3‐E1 cell behavior was affected by surface topography, chemistry, and wettability simultaneously and that cells showed strong responses to surface topography. On fiber‐dominant surface, cells fully spread with obvious cytoskeleton organization and exhibited significantly higher level of adhesion and proliferation compared with particle‐ or granule‐dominant surfaces. Furthermore, fiber‐dominant surface also induced greater expression of mature osteogenic marker osteocalcin and higher mineralization based on RT‐PCR and von Kossa staining. The results suggest that topographic modification of chitosan substratum at the nanoscale may be exploited in regulating cell behavior for its applications in tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Osteoblast response to continuous phase macroporous scaffolds under static and dynamic culture conditions
Authors: Meretoja Ville V. , Malin Minna , Seppälä Jukka V. , Närhi Timo O.
Published: April 2008

Average scaffold pore sizes in the order of several hundred microns are generally required for efficient bone tissue ingrowth in vivo, whereas the culture of large bone engineering constructs in vitro can require bioreactor cultures to decrease diffusional constraints on the cells. In this study, we prepared poly(ε‐caprolactone/D,L‐lactide)‐based scaffolds with continuous phase macroporosity using a novel CaCl2 · 6H2O porogen agent. Osteogenic differentiation and scaffold colonization in rat bone marrow stromal cell cultures were compared in such polymer scaffolds, and in composites with 30 wt % bioactive glass filler. The effect of a rotating wall bioreactor culture on the cell response was also evaluated. Bioactive filler enhanced proliferation, early osteogenic differentiation, and mineralization of the cultured cells under static conditions. Dynamic cultures, in turn, resulted in decreased cell numbers and inhibition of the differentiation process irrespective of the scaffold type. This effect was ascribed to the harsh mechanical stresses caused by constant collisions of the scaffolds in the bioreactor vessels. However, cells were able to penetrate into the scaffold interior only under dynamic culture conditions. Thus, interconnected macroporosity is an essential, but not sufficient, condition to allow for full colonization of millimeter scale tissue engineering scaffolds in vitro. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Nasal chondrocytes and fibrin sealant for cartilage tissue engineering
Authors: Vinatier C. , Gauthier O. , Masson M. , Malard O. , Moreau A. , Fellah B. H. , Bilban M. , Spaethe R. , Daculsi G. , Guicheux J.
Published: April 2008

Hybrid constructs associating a biodegradable matrix and autologous chondrocytes hold promise for the treatment of articular cartilage defects. In this context, our objective was to investigate the potential use of nasal chondrocytes associated with a fibrin sealant for the treatment of articular cartilage defects. The phenotype of primary nasal chondrocytes (NC) from human (HNC) and rabbit (RNC) origin were characterized by RT‐PCR. The ability of constructs associating fibrin sealant and NC to form a cartilaginous tissue in vivo was investigated, firstly in a subcutaneous site in nude mice and secondly in an articular cartilage defect in rabbit. HNC express type II collagen and aggrecan, the two major hallmarks of a chondrocytic phenotype. Furthermore, when injected subcutaneously into nude mice within a fibrin sealant, these chondrocytes were able to form a cartilage‐like tissue. Our data indicate that RNC also express type II collagen and aggrecan and maintained their phenotype in three‐dimensional culture within a fibrin sealant. Moreover, treatment of rabbit articular cartilage defects with autologous RNC embedded in a fibrin sealant led to the formation of a hyalin‐like repair tissue. The use of fibrin sealant containing hybrid autologous NC therefore appears as a promising approach for cell‐based therapy of articular cartilage. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Photoinduced in situ formation of various F‐actin assemblies with a photoresponsive polycation
Authors: Misu Manami , Furukawa Hidemitsu , Kwon Hyuck‐Joon , Shikinaka Kazuhiro , Kakugo Akira , Satoh Toshifumi , Osada Yoshihito , Gong Jian Ping
Published: April 2008

We developed a novel in situ method for the control of F‐actin assembly by using a synthetic photoresponsive polycation. The photoresponsive polycation mainly comprises a water‐soluble cationic monomer and also contains a small amount of the monomer of a triphenylmethane leucohydroxide derivative (20 mol %), which is a well‐known photochromic molecule that can be cationized in aqueous solution by ultra violet (UV) irradiation, thereby causing an increase in the total charge on the photoresponsive polycation. Thus, by exposure to UV radiation in aqueous solution, F‐actin and the photoresponsive polycation start assembling into F‐actin/photoresponsive polycation complexes of various morphologies such as bundles, coils, and networks, depending upon the concentrations of both the F‐actin and salt. Further, localized UV irradiation can be applied in order to control the local formation of F‐actin/photoresponsive polycation complexes. Thus, this technique provides a novel method for the spatiotemporal control of F‐actin assembly and can be applied to investigate the unknown characteristics of F‐actin. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Efficiency of controlled topical delivery of silver sulfadiazine in infected burn wounds
Authors: Shanmugasundaram N. , Uma T. S. , Ramyaa Lakshmi T. S. , Babu Mary
Published: April 2008

The present study is designed to assess the potential benefits of controlled delivery of silver sulfadiazine from collagen scaffold (SSDM‐CS) in infected deep partial thickness burn wounds in which epidermis is lost completely and the entire papillary dermis and most of the recticular layer of the dermis is lost. Infection induced by inoculating 107 colony forming units (cfu) of Pseudomonas aeruginosa caused significant increase in wound size (20%) till day 15, which decreased significantly from day 9 by SSDM‐CS treatment, showing complete healing by day 27 (control ≥ 37 days). Early subsidence of infection (<102 cfu, day 9) by SSDM‐CS resulted in faster epidermal resurfacing and fibroplasia, whereas heavy microbial load (>107 cfu, day 9) in controls caused severe inflammatory cellular infiltration. Persistent infection triggered early expression of proinflammatory cytokines intereukin‐6, intereukin 1‐β, and tumor necrosis factor‐α, lasting until day 9, whereas cytokine level decreased in SSDM‐CS‐treated group by day 6. Infection exacerbated expression of active matrix metalloproteinases (MMPs)‐2 and ‐9 in controls (day 15), while SSDM‐CS positively modulated MMP‐2 and ‐9 with faster decline in their levels (day 12). Inherent nature of the dressing to maintain drug level at equilibrium therapeutic concentration (51.2 μg/mL) for prolonged time (72 h), below systemic toxic limits (20 μg/dL, serum level), accelerated the magnitude and sequence of reparative events. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Nickel release behavior and surface characteristics of porous NiTi shape memory alloy modified by different chemical processes
Authors: Wu Shuilin , Liu Xiangmei , Chan Y. L. , Chu Paul K. , Chung C. Y. , Chu Chenglin , Yeung Kelvin W. K. , Lu W. W. , Cheung Kenneth M. C. , Luk K. D. K.
Published: April 2008

As a non‐line‐of‐sight surface modification technique, chemical treatment is an effective method to treat porous NiTi with complex surface morphologies and large exposed areas due to its liquidity and low temperature. In the work described here, three different chemical processes are used to treat porous NiTi alloys. Our results show that H2O2 treatment, NaOH treatment, and H2O2 pre‐treatment plus subsequent NaOH treatment can mitigate leaching of nickel from the alloy. The porous NiTi samples modified by the two latter processes favor deposition of a layer composed of Ca and P due to the formation of bioactive Na2TiO3 on the surface. Among the three processes, H2O2 pre‐treatment plus subsequent NaOH modification is the most effective in suppressing nickel release. Small area X‐ray photoelectron spectroscopy reveals that the surfaces treated by different chemical processes have different structures and compositions. The sample modified by the H2O2 treatment is composed of rough TiO2 on the outer surface and an oxide transition layer underneath whereas the sample treated by NaOH comprises a surface layer of titanium oxide and Na2TiO3 together with a transition layer. The sample processed by the H2O2 and NaOH treatment has a pure Na2TiO3 layer on the surface and a transition layer underneath. These results help to elucidate the different nickel release behavior and bioactivity of porous NiTi alloys processed by different methods. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Development of dual‐compartment perfusion bioreactor for serial coculture of hepatocytes and stellate cells in poly(lactic‐co‐glycolic acid)‐collagen scaffolds
Authors: Wen F. , Chang S. , Toh Y. C. , Arooz T. , Zhuo L. , Teoh S. H. , Yu H.
Published: April 2008

An important challenge in liver tissue engineering is to overcome the rapid loss of hepatocyte functions. In vivo, hepatocytes are compact polyhedral cells with round nuclei; however, they readily loss many of their differentiated functions in vitro. To overcome this challenge, we have established a new perfusion bioreactor that consists of two compartments which enabled the serial coculture of hepatocytes and hepatic stellate cells‐T6 without direct contact between each other. Three dimensional scaffolds were utilized in the bioreactor as physical anchors for cells. The scaffolds consist of collagen grafted poly(lactic‐co‐glycolic acid) microfibers and cross‐linked collagen sponges between microfibers for additional cellular support and adhesion. The advantages of this new bioreactor are enabling cell culture in three dimensional organization and controlling the culture parameters of the supporting cells independently from the hepatocytes. The results showed that the hepatocytes exhibited much higher levels of the differentiated functions such as albumin secretion, urea synthesis, and cytochrome P450 enzymatic activity when compared with the monoculture system where hepatocytes alone were cultured. This perfusion bioreactor system has potential applications in the development of bioartificial liver devices or cell‐based tissue constructs transplantation therapies. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Osteogenic differentiation of mesenchymal stem cells in defined protein beads
Authors: Lund Amanda W. , Bush Jeff A. , Plopper George E. , Stegemann Jan P.
Published: April 2008

There is a need to develop improved methods for directing and maintaining the differentiation of human mesenchymal stem cells (hMSC) for regenerative medicine. Here, we present a method for embedding cells in defined protein microenvironments for the directed osteogenic differentiation of hMSC. Composite matrices of collagen I and agarose were produced by emulsification and simultaneous polymerization in the presence of hMSC to produce 30–150 μm diameter hydrogel “beads.” The proliferation, morphology, osteogenic gene expression, and calcium deposition of hMSC in bead environments were compared to other two‐ and three‐dimensional culture environments over 14–21 days in culture. Cells embedded within 40% collagen beads exhibited equivalent proliferation rates to those in gel disks, but showed upregulation of bone sialoprotein and increased calcium deposition over 2D controls. Osteocalcin gene expression was not changed in 3D beads and disks, while collagen type I gene expression was downregulated relative to cells in 2D culture. The hydrogel bead format allows controlled cell differentiation and is a cell delivery vehicle that may also enhance vascular invasion and host incorporation. Our results indicate that the application of such beads can be used to promote the osteogenic phenotype in hMSC, which is an important step toward using them in bone repair applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
The audit committee: How should it handle ERM?
Authors: Burton E. James
Published: April 2008

The role of the audit committee seems to be constantly changing. Audit committees are being given ever‐greater responsibilities lately. Some authorities seem to use them as a dumping ground for whatever extra responsibilities they want companies to shoulder.

The latest controversy may be over enterprise risk management (ERM). Should it be added to the audit committee agenda? And, if so, how should this be done? © 2008 Wiley Periodicals, Inc.
Covert investigations in the workplace
Authors: Tackett James A.
Published: April 2008

Mention a covert investigation and Hollywood images of James Bond or cloak‐and‐dagger operations come to mind. In reality, covert investigations are far less glamorous—and have become routine in many large business organizations.

But you still must proceed carefully. A slipshod investigation can result in major lawsuits, serious injury, or even death. The author discusses covert investigations, explains when you need a professional investigator, and offers some general guidelines. © 2008 Wiley Periodicals, Inc.
Find project risk before it bites you
Authors: Iijima Timothy
Published: April 2008

Projects are a significant part of many companies' spending. Many projects are small and end quickly. But some can last for years—and create surprising risk that can come back and bite you.

To prevent that, you must audit those projects. The author reveals how to do it. © 2008 Wiley Periodicals, Inc.
SIVs: Could you survive a financial collapse?
Authors: Ehrlich Michael , Anandarajan Asokan
Published: April 2008

The newspapers are suddenly full of worries about structured investment vehicles (SIVs). These are huge, risky investment instruments used by large banks and hedge funds. But fund managers of major companies have invested in money markets, which in turn—unknown to the company fund managers—have invested in the risky SIVs.

Any major collapse of the SIVs could spread financial panic. So what are corporate managers to do? Are there strategies to avoid financial disaster? And what questions should auditors ask right now? © 2008 Wiley Periodicals, Inc.
How to monitor internal controls
Authors: Colbert Jan
Published: April 2008

Internal controls are critical for any organization to function effectively. And with an effective system of controls in place, you minimize risk. But how should you monitor controls to ensure their quality and performance? © 2008 Wiley Periodicals, Inc.
SEC/PCAOB conference highlights
Authors: Ciesielski Jack T. , Weirich Thomas R.
Published: April 2008

The recent Securities and Exchange Commission (SEC)/Public Company Accounting Oversight Board (PCAOB) Conference addressed some issues of special interest to auditors. Time is an auditor's most valuable asset. So why waste time letting a client pursue an easily challenged accounting treatment if the SEC has already described its approach to handling it? Forewarned is forearmed, and this conference provided auditors and companies with plenty of forewarning. © 2008 Wiley Periodicals, Inc.
Why intercompany matters
Authors: O'Connor Jim , Liao Sherri
Published: April 2008

Recent trends have sparked companies to take a loser look at “back‐of‐the‐house” operations—where dangerous problems often lurk undetected. © 2008 Wiley Periodicals, Inc.
Customer profitability
Authors: Miller John A.
Published: April 2008

Customer profitability quantifies the “in‐the‐bank” profits of the customer/supplier relationship and reports what's already been earned. More important to many industries is customer valuation, the future value of the customer. This article explains how the two differ—and why it matters. © 2008 Wiley Periodicals, Inc.
Enumeration of generalized Hadamard matrices of order 16 and related designs
Authors: Gibbons P. B. , Mathon R.
Published: April 2008

We investigate signings of symmetric GDD($16 \times 2^i$, 16, $2^{4-i}$)s over $Z_2$ for $1 \le i \le 3$. Beginning with $i=1$, at each stage of this process a signing of a GDD($16 \times 2^i$, 16, $2^{4-i}$) produces a GDD($16 \times 2^{i+1}$, 16, $2^{4-i-1}$). The initial GDDs ($i=1$) correspond to Hadamard matrices of order 16. For $i=3$, the GDDs are semibiplanes of order 16, and for $i=4$ the GDDs are semiplanes of order 16 which can be extended to projective planes of order 16. In this article, we completely enumerate such signings which include all generalized Hadamard matrices of order 16. We discuss the generation techniques and properties of the designs obtained during the search. © 2008 Wiley Periodicals, Inc. J Combin Designs 17: 119–135, 2009
Biotransformation of three aromadendrane‐type sesquiterpenoids by Aspergillus wentii
Authors: Miyazawa Mitsuo , Takahashi Tomohiko , Sakata Kazuki , Horibe Isao
Published: April 2008

BACKGROUND: The biotransformation of sesquiterpenoids, which are a large class of naturally occurring compounds, using microorganisms as a biocatalyst to produce useful novel organic compounds was investigated. The biotransformation of sesquiterpenoids, (+)‐aromadendrene (1), (−)‐alloaromadendrene (2) and (+)‐ledene (3) has been investigated using Aspergillus wentii as a biocatalyst.

Results: Compound 1 was converted to (−)‐(10S,11S)‐10,13,14‐trihydroxyaromadendrane (4). Compound 2 was converted to (+)‐(1S,11S)‐1,13‐dihydroxyaromadendrene (5) and (−)‐5,11‐epoxycadin‐1(10)‐en‐14‐ol (6). Compound 3 was converted to compound 6, (+)‐(10R,11S)‐10,13‐dihydroxyaromadendr‐1‐ene (7) and (+)‐(10S,11S)‐10,13‐dihydroxyaromadendr‐1‐ene (8). The structure of the metabolic products has been elucidated on the basis of their spectral data.

CONCLUSION: Compound 1 gave only one product that was hydroxylated at C‐10, C‐13 and C‐14. By contrast, compounds 2 and 3 gave a number of products, one of which was common. The differences in oxidation of 1–3 are due to the configuration of the C‐1 position. Compounds 4–8 were new compounds. Copyright © 2008 Society of Chemical Industry
High‐flow priapism complicating ischemic priapism following iatrogenic laceration of the dorsal artery during a Winter procedure
Authors: Bertolotto Michele , Ciampalini Sandro , Martingano Paola , Mucelli Fabio Pozzi
Published: April 2008

We report a case of a patient who developed high‐flow priapism following a Winter procedure performed for the treatment of low‐flow ischemic priapism. During the creation of bilateral cavernosal–glandular shunts, the tip of the left dorsal artery was accidentally lacerated. A fistula developed through the shunt between the torn artery and the cavernosal sinusoids of the tip of the left corpus cavernosum. Gray‐scale and Doppler sonography and angiography allowed diagnosis and guided the therapeutic approach. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
One‐step preparation of hybrid materials of polyacrylamide networks and gold nanoparticles
Authors: Song Yonghai , Li Zhiqiang , Wang Li , Yao Yong , Chen Chuangye , Cui Kang
Published: April 2008

Hybrid materials of polyacrylamide networks and gold nanoparticles were prepared by directly heating an aqueous solution containing HAuCl4, acrylamide, N,N′‐methylenebis‐acrylamide, and sodium sulfite (Na2SO3). Acrylamide, N,N′‐methylenebis‐acrylamide, and Na2SO3 were used as monomers, crosslinking agent, and initiator, respectively. In the process of polyacrylamide network synthesis, HAuCl4 was reduced by acrylamide and Na2SO3 into gold nanoparticles and adsorbed on the produced polyacrylamide networks. Transmission electron microscopy proved that the size of gold nanoparticles was in the range of 3–10 nm. Atomic force microscopy showed that the gold nanoparticles homogeneously dispersed into the polyacrylamide networks matrix. The hybrid materials as absorbents may be useful in healthcare, communication technology, building industry, chromatography, water purification, and agriculture. Microsc. Res. Tech., 2008. © 2008 Wiley‐Liss, Inc.
A Characterization of the degree sequences of 2‐trees
Authors: Bose Prosenjit , Dujmović Vida , Krizanc Danny , Langerman Stefan , Morin Pat , Wood David R. , Wuhrer Stefanie
Published: April 2008

A graph G is a 2‐tree if G = K3, or G has a vertex v of degree 2, whose neighbors are adjacent, and G/ v is a 2‐ tree. A characterization of the degree sequences of 2‐trees is given. This characterization yields a linear‐time algorithm for recognizing and realizing degree sequences of 2‐trees. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:191‐209, 2008
Disjoint quasi‐kernels in digraphs
Authors: Heard Scott , Huang Jing
Published: April 2008

A quasi‐kernel in a digraph is an independent set of vertices such that any vertex in the digraph can reach some vertex in the set via a directed path of length at most two. Chvátal and Lovász proved that every digraph has a quasi‐kernel. Recently, Gutin et al. raised the question of which digraphs have a pair of disjoint quasi‐kernels. Clearly, a digraph has a pair of disjoint quasi‐kernels cannot contain sinks, that is, vertices of outdegree zero, as each such vertex is necessarily included in a quasi‐kernel. However, there exist digraphs which contain neither sinks nor a pair of disjoint quasi‐kernels. Thus, containing no sinks is not sufficient in general for a digraph to have a pair of disjoint quasi‐kernels. In contrast, we prove that, for several classes of digraphs, the condition of containing no sinks guarantees the existence of a pair of disjoint quasi‐kernels. The classes contain semicomplete multipartite, quasi‐transitive, and locally semicomplete digraphs. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:251‐260, 2008