bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of antitubercular drug‐loaded surfactants as inhalable drug‐delivery systems for pulmonary tuberculosis
Authors: Chimote G. , Banerjee R. 
Published: April 2008

AbstractPulmonary 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

AbstractUrease 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

AbstractThis 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

AbstractThe 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

AbstractIn 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

AbstractAverage 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

AbstractHybrid 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

AbstractWe 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

AbstractThe 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

AbstractAs 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

AbstractAn 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

AbstractThere 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

AbstractThe 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

AbstractMention 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.
SIVs: Could you survive a financial collapse?
Authors: Ehrlich Michael , Anandarajan Asokan 
Published: April 2008

AbstractThe 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.
SEC/PCAOB conference highlights
Authors: Ciesielski Jack T. , Weirich Thomas R. 
Published: April 2008

AbstractThe 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.
Enumeration of generalized Hadamard matrices of order 16 and related designs
Authors: Gibbons P. B. , Mathon R. 
Published: April 2008

AbstractWe 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