bluuebunny/crossref_metadata_2025 huggingface dataset:
Chimeric, divalent and tetravalent anti‐CD19 monoclonal antibodies with potent in vitro and in vivo antitumor activity against human B‐cell lymphoma and pre‐B acute lymphoblastic leukemia cell lines
Authors: Liu Xiao‐Yun , Pop Laurentiu M. , Tsai Lydia , Pop Iliodora V. , Vitetta Ellen S.
Published: September 2010

CD19 is an attractive therapeutic target for treating human B‐cell tumors. In our study, chimeric (c) divalent (cHD37) and tetravalent (cHD37‐DcVV) anti‐CD19 monoclonal antibodies (MAbs) were constructed, expressed and evaluated for their binding to human 19‐positive (CD19+) tumor cell lines. They were also tested for proapoptotic activity and the ability to mediate effector functions. The antitumor activity of these MAbs was further tested in mice xenografted with the CD19+ Burkitt's lymphoma cell line, Daudi or the pre‐B acute lymphoblastic leukemia (ALL) cell line, NALM‐6. The cHD37 and cHD37‐DcVV MAbs exhibited specific binding and comparable proapoptotic activity on CD19+ tumor cell lines in vitro. In addition, the cHD37 and cHD37‐DcVV MAbs were similar in their ability to mediate antibody‐dependent cell‐mediated phagocytosis (ADCP). However, the tetravalent cHD37‐DcVV MAb bound more avidly, had a slower dissociation rate, and did not internalize as well. It also had enhanced antibody‐dependent cellular cytotoxicity (ADCC) with human but not murine effector cells. The cHD37 and cHD37‐DcVV MAbs exhibited comparable affinity for the human neonatal Fc receptor (FcRn) and similar pharmacokinetics (PKs) in mice. Moreover, all the HD37 constructs were similar in extending the survival of mice xenografted with Daudi or NALM‐6 tumor cells. Therefore, the cHD37 and cHD37‐DcVV MAbs have potent antitumor activity and should be further developed for use in humans. Although not evident in mice, due to its increased ability to mediate ADCC with human but not mouse effector cells, the cHD37‐DcVV MAb should have superior therapeutic efficacy in humans.
Trends in head and neck cancer incidence in Denmark, 1978–2007: Focus on human papillomavirus associated sites
Authors: Blomberg Maria , Nielsen Ann , Munk Christian , Kjaer Susanne Krüger
Published: September 2010

The aim of our study was to assess the overall trends in the incidence of head‐and‐neck cancer (HNC) among Danish men and women in 1978–2007, to describe the distribution and incidences of HNCs at different anatomical sites, and to determine whether the incidence of human papillomavirus (HPV)‐associated cancers is increasing. Data were extracted from the nationwide Cancer Registry database. To assess the possible impact of HPV infection, the sites of squamous cell carcinomas were categorized as HPV‐associated, potentially HPV‐associated or HPV‐unrelated. In total, 26,474 incident cases were identified and the overall incidence increased throughout the period. Significantly increasing incidence rates were notably seen for tumors in the oral cavity (2.2% per year), tonsils (4.8% per year), oropharynx (3.5% per year) and hypopharynx (4.4% per year). A significantly decreasing incidence of lip cancer was observed among men (–5.0% per year). Cancers at HPV‐associated sites (n = 3650) showed strongly increasing incidence rates, primarily in individuals < 60 years. In contrast, HNCs at sites not related to HPV infection showed a significant decrease (in men) or virtually no change in incidence (in women). Our results suggest a marked impact of HPV infection on the epidemiology of HNCs in Denmark. HPV16 is the type most often found in HNCs; thus, the recent introduction of vaccination against HPV may in the future prevent HPV‐associated cancers of the head and neck.
Dietary polyunsaturated fatty acids and breast cancer risk in Chinese women: A prospective cohort study
Authors: Murff Harvey J. , Shu Xiao‐Ou , Li Honglan , Yang Gong , Wu Xiauyan , Cai Hui , Wen Wanqing , Gao Yu‐Tang , Zheng Wei
Published: September 2010

Breast cancer is the most common cancer in women. Controversy exists regarding the role of dietary fat in breast cancer etiology. We investigated the association of dietary polyunsaturated fatty acids (PUFAs) and the ratio of n‐6 PUFAs to marine‐derived n‐3 PUFAs with breast cancer risk in the Shanghai Women's Health Study, a prospective cohort study including 72,571 cancer‐free participants at baseline. Dietary fatty acid intake was determined using food frequency questionnaires. We used Cox proportional hazards analysis to estimate the relative risks (RRs) and 95% confidence intervals (CIs) for the association of breast cancer risk with dietary fatty acids consumption. In 583,998 person‐years of follow‐up, we identified 712 breast cancer cases. We found no association of breast cancer risk to dietary intake of linoleic acid, arachidonic acid, α‐linolenic acid or marine‐derived n‐3 PUFA. We found a statistically significant interaction between n‐6 PUFA intake, marine‐derived n‐3 PUFA intake and breast cancer risk (p = 0.008). Women with lower intake (the lowest tertile) of marine‐derived n‐3 PUFA and higher intake (the highest tertile) of n‐6 PUFA had an increase risk for breast cancer (RR = 2.06; 95% CI = 1.27–3.34) compared to women with higher intake (the highest tertile) of marine‐derived n‐3 PUFAs and lower intake (the lowest tertile) of n‐6 PUFAs after adjusting for potential confounders. The relative amounts of n‐6 PUFA to marine‐derived n‐3 PUFAs may be more important for breast cancer risk than individual dietary amounts of these fatty acids.
Gene expression profiling reveals novel biomarkers in nonsmall cell lung cancer
Authors: Sanchez‐Palencia Abel , Gomez‐Morales Mercedes , Gomez‐Capilla Jose Antonio , Pedraza Vicente , Boyero Laura , Rosell Rafael , Fárez‐Vidal Mª Esther
Published: September 2010

The development of reliable gene expression profiling technology is having an increasing impact on our understanding of lung cancer biology. Our study aimed to determine any correlation between the phenotypic heterogeneity and genetic diversity of lung cancer. Microarray analysis was performed on a set of 46 tumor samples and 45 paired nontumor samples of nonsmall cell lung cancer (NSCLC) samples to establish gene signatures in primary adenocarcinomas and squamous‐cell carcinomas, determine differentially expressed gene sequences at different stages of the disease and identify sequences with biological significance for tumor progression. After the microarray analysis, the expression level of 92 selected genes was validated by qPCR and the robust Bonferroni test in an independent set of 70 samples composed of 48 tumor samples and 22 nontumor samples. Gene sequences were differentially expressed as a function of tumor type, stage and differentiation grade. High upregulation was observed for KRT15 and PKP1, which may be good markers to distinguish squamous‐cell carcinoma samples. High downregulation was observed for DSG3 in stage IA adenocarcinomas.
Nonparametric estimation of the impact of taxes on female labor supply
Authors: Kumar Anil
Published: September 2010

This paper proposes a simple extension of nonparametric estimation methods for nonlinear budget‐set models derived in Blomquist and Newey (2002) to censored dependent variables. The nonparametric method is applied to estimate female labor supply elasticities using data on married women from the 1985 and 1989 waves of the Panel Study of Income Dynamics, exploiting the substantial variation in budget sets caused by the Tax Reform Act of 1986 as a source of identification. The estimated wage elasticities from this new method are 0.56 overall and 0.27 on the intensive margin. The income elasticity estimates are close to − 0.67 overall and − 0.13 on the intensive margin. Compared with the linear labor supply model, the estimated elasticities are usually larger for the nonparametric specifications that account for nonlinear budget sets. Copyright © 2010 John Wiley & Sons, Ltd.
MicroRNA expression changes during zebrafish development induced by perfluorooctane sulfonate
Authors: Zhang Ling , Li Yuan‐yuan , Zeng Huai‐cai , Wei Jie , Wan Yan‐jian , Chen Jun , Xu Shun‐qing
Published: September 2010

Perfluorooctane sulfonate (PFOS), a kind of widely distributed environmentally organic compound, has been found to cause developmental toxicity. Although microRNAs (miRNAs) play an important role in many metabolic tasks, whether and how they are involved in the process of PFOS‐induced toxicity is largely unknown. To address this problem, PFOS‐induced changes in miRNAs and target gene expression in zebrafish embryos, and the potential mechanism of PFOS‐induced toxic action were studied in this research. Zebrafish embryos were exposed to 1 µg ml−1PFOS or DMSO control from 6 h post‐fertilization (hpf) to 24 or 120 hpf. Subsequently, RNA was isolated from the embryo pool and the expression profiles of 219 known zebrafish miRNAs were analyzed using microarray. Finally, quantitative real‐time polymerase chain reaction was used to validate several miRNAs expression of microarray data. The analysis revealed that PFOS exposure induced significant changes in miRNA expression profiles. A total of 39 and 81 miRNAs showed significantly altered expression patterns after PFOS exposure 24 and 120 hpf. Of the changed miRNAs, 20 were significantly up‐regulated and 19 were significantly down‐regulated (p< 0.01) at 24 hpf, whereas 41 were significantly up‐regulated and 40 were significantly down‐regulated (p< 0.01) at 120 hpf. These miRNAs were involved in development, apoptosis and cell signal pathway, cell cycle progression and proliferation, oncogenesis, adipose metabolism and hormone secretion, whereas there is still little functional information available for 32 miRNAs. Our results demonstrate that PFOS exposure alters the expression of a suite of miRNAs and may induce developmental toxicity. Copyright © 2010 John Wiley & Sons, Ltd.
Protective effect of C60‐methionine derivate on lead‐exposed human SH‐SY5Y neuroblastoma cells
Authors: Chen Tian , Li Yuan‐Yuan , Zhang Jin‐Long , Xu Bin , Lin Yi , Wang Chun‐Xiang , Guan Wen‐Chao , Wang You‐Jie , Xu Shun‐Qing
Published: September 2010

Oxidative stress has been considered as one of the possible mechanisms leading to the neurotoxicity of lead. One of the effective ways to prevent cellular damage after lead exposure is using antioxidants. In this paper, a novel C60‐methionine derivate (FMD), a fullerene molecule modified with methionine, was synthesized. The protective effect of FMD on lead‐exposed human SH‐SY5Y neuroblastoma cells was investigated. In this research, after incubating with 500 µm Pb acetate alone for 72 h, the cells had undergone a series of biological changes including viability loss, apoptotic death, the depletion of glutathione (GSH), the peroxidation of membrane lipid and DNA damage. Pretreatment with FMD before lead exposure could improve cell survival, increase the GSH level, reduce malondialdehyde content and attenuate DNA damage without obvious toxicity. In addition, the protective effects of FMD were proven to be greater than those of other two C60‐amino acid derivates, β‐alanine C60 derivate and cystine C60 derivate, which have been confirmed in our previous work to be able to protect rat pheochromocytoma PC12 cells from hydrogen dioxide‐induced oxidative injuries. These observations suggest that FMD may serve as a potential antioxidative and neuroprotective agent in the prevention of lead intoxication. Copyright © 2010 John Wiley & Sons, Ltd.
Label‐free imaging and analysis of the effects of lipolysis products on primary hepatocytes
Authors: Schie Iwan W. , Wu Jian , Weeks Tyler , Zern Mark A. , Rutledge John C. , Huser Thomas
Published: September 2010

The increased accumulation of intracellular lipid droplets within hepatocytes is a pathologic hallmark of liver injury of various etiologies, especially non‐alcoholic steatohepatitis (NASH). The dynamics, subcellular origin, and chemical composition of lipid droplets under various pathophysiologic conditions, however, remain poorly understood. We used coherent Raman microscopy and spontaneous Raman spectroscopy to monitor and analyze the formation of lipid droplets in living primary rat hepatocytes exposed to triglyceride‐rich lipoprotein (TGRL) lipolysis products. After exposure to the complex fatty acid mixture released during the lipolysis process for 30 minutes, new lipid droplets rapidly appeared within hepatocytes and increased in size and number over the total observation period of 205 minutes. Raman spectroscopic analysis of individual intracellular lipid droplets before and after exposure to lipolysis products reveals that the major components of these droplets are esterified unsaturated fatty acids. We find that the fatty acid unsaturation ratio increases with droplet size. Control experiments with defined fatty acid mixtures reveal the complexity of the cellular response to assault by combinations of lipids. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biocompatibility evaluation of HDPE‐UHMWPE reinforced β‐TCP nanocomposites using highly purified human osteoblast cells
Authors: Shokrgozar M. A. , Farokhi M. , Rajaei F. , Bagheri M. H. A , Azari SH. , Ghasemi I. , Mottaghitalab F. , Azadmanesh K. , Radfar J.
Published: September 2010

Biocompatibility of β‐TCP/HDPE‐UHMWPE nanocomposite as a new bone substitute material was evaluated by using highly purified human osteoblast cells. Human osteoblast cells were isolated from bone tissue and characterized by immunofluorescence Staining before and after purification using magnetic bead system. Moreover, proliferation, alkaline phosphatase production, cell attachment, calcium deposition, gene expression, and morphology of osteoblast cells on β‐TCP/HDPE‐UHMWPE nanocomposites were evaluated. The results have shown that the human osteoblast cells were successfully purified and were suitable for subsequent cell culturing process. The high proliferation rate of osteoblast cells on β‐TCP/HDPE‐UHMWPE nanocomposite confirmed the great biocompatibility of the scaffold. Expression of bone‐specific genes was taken place after the cells were incubated in composite extract solutions. Furthermore, osteoblast cells were able to mineralize the matrix next to composite samples. Scanning electron microscopy demonstrated that cells had normal morphology on the scaffold. Thus, these results indicated that the nanosized β‐TCP/HDPE‐UHMWPE blend composites could be potential scaffold, which is used in bone tissue engineering. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
In vitro and in vivo release of nerve growth factor from biodegradable poly‐lactic‐co‐glycolic‐acid microspheres
Authors: de Boer Ralph , Knight Andrew M. , Spinner Robert J. , Malessy Martijn J. A. , Yaszemski Michael J. , Windebank Anthony J.
Published: September 2010

Regeneration of peripheral nerves after injury is suboptimal. We now report the long term delivery of nerve growth factor (NGF) by biodegradable poly‐lactic‐co‐glycolic acid (PLGA) microspheres in vitro and in vivo. Lactic to glycolic acid ratios of 50:50 and 85:15 were fabricated using the double emulsion solvent, evaporation technique. Three different inherent viscosities (0.1 dL g−1: 1A, 0.4 dL g−1: 4A, 0.7 dL g−1: 7A) were analyzed. In vitro, release of NGF for 23 days was measured. Electron microscopy demonstrated intact spheres for at least 7 days (50:50 1A), 14 days (50:50 4A), or 35 days (50:50 7A and 85:15 7A). In vitro release kinetics was characterized by burst release, followed by release of NGF at a rate of 0.6–1.6% a day. Release curves for 50:50 1A and 85:15 7A differed significantly from other compositions (p < 0.01). In vivo, release was characterized by a novel radionuclide tracking assay. Release rates varied from 0.9 to 2.2% per day with linear kinetics. All but the 85:15 type of spheres showed different release profiles in vivo compared to in vitro conditions. On the basis of the surface morphology and release profiles, we found microspheres fabricated from 50:50 4A PLGA to be best suited for the use in a rat sciatic nerve injury model. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
The synthesis and characterization of nanophase hydroxyapatite using a novel dispersant‐aided precipitation method
Authors: Cunniffe Gráinne M. , O'Brien Fergal J. , Partap Sonia , Levingstone Tanya J. , Stanton Kenneth T. , Dickson Glenn R.
Published: September 2010

The synthesis of nanophase hydroxyapatite (nHA) is of importance in the field of biomaterials and bone tissue engineering. The bioactive and osteoconductive properties of nHA are of much benefit to a wide range of biomedical applications such as producing bone tissue engineered constructs, coating medical implants, or as a carrier for plasmid DNA in gene delivery. This study aimed to develop a novel low‐temperature dispersant‐aided precipitation reaction to produce nHA particles (<100 nm), which are regarded as being preferable to micron‐sized agglomerates of nHA. The variables investigated and optimized include the reaction pH, the rate of reactant mixing, use of sonication, order of addition, and concentration of the primary reactants, in addition, the effect of using poly(vinyl alcohol) (PVA) surfactant and Darvan 821A® dispersing agent during the reaction was also examined. It was found that by fine‐tuning the synthesis parameters and incorporating the dispersing agent, monodisperse, phase‐pure nano‐sized particles under 100 nm were attained, suitable for clinical applications in bone regeneration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Effects of electrodeposited poly(ethylene glycol) on biofilm adherence to titanium
Authors: Tanaka Yuta , Matin Khairul , Gyo Mariko , Okada Ayako , Tsutsumi Yusuke , Doi Hisashi , Nomura Naoyuki , Tagami Junji , Hanawa Takao
Published: September 2010

Protein‐resistant coatings have been studied for inhibiting biofilm formation on implant devices. In this study, titanium (Ti) surfaces were biofunctionalized with poly(ethylene glycol) (PEG) by electrodeposition and were evaluated as biofilm substrates under an oral simulated environment. Streptococcus gordonii, an early colonizer of oral biofilms, was inoculated on Ti and PEG‐electrodeposited Ti (PEG‐Ti) surfaces and was analyzed quantitatively and topographically. Streptococcus mutans supplemented with sucrose, a late colonizer mainly found in dental plaque, was also used to form biofilms on the surfaces of Ti and PEG‐Ti for 20 h followed by sonication as a means of detaching the biofilms. The results indicated that the attachment of S. gordonii on PEG‐Ti surfaces was inhibited compared with Ti, and the S. mutans biofilm was easier to be detached from the surface of PEG‐Ti than that of Ti. Moreover, the presence of PEG electrodeposited on Ti surface inhibited salivary protein adsorption. The degree of detachment of biofilms from PEG‐Ti was associated with the inhibition of the salivary protein adsorption, suggesting weak basal attachment of the biofilms to the electrodeposited surfaces. Therefore, controlling protein adsorption at the initial stage of biofilm formation may be an effective strategy to protect metal surfaces from bacterial contamination not only in dental manipulations but also in orthopedic applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Composite scaffolds: Bridging nanofiber and microsphere architectures to improve bioactivity of mechanically competent constructs
Authors: Brown Justin L. , Peach M. Sean , Nair Lakshmi S. , Kumbar Sangamesh G. , Laurencin Cato T.
Published: September 2010

Tissue engineering often benefits from the use of composites to produce an ideal scaffold. We present the focused development of a novel structure that combines the biomimetic properties of nanofibers with the robust mechanical aspects of the sintered microsphere scaffold to produce a composite scaffold that demonstrates an ability to mimic the mechanical environment of trabecular bone while also promoting the phenotype progression of osteoblast progenitor cells. These composite nanofiber/microsphere scaffolds exhibited a mechanical modulus and compressive strength similar to trabecular bone and exhibited degradation resulting in a mass loss of 30% after 24 weeks. The nanofiber portion of these scaffolds was sufficiently porous to allow cell migration throughout the fibrous portion of the scaffold and promoted phenotype progression through focal adhesion kinase‐mediated activation of the transcription factor Runx2, control scaffolds not containing nanofibers did not demonstrate extensive cell migration or phenotype progression. Ultimately, the focal adhesion kinase activity on the composite nanofiber/microsphere scaffolds demonstrated causality over the production of the mature osteoblast marker, osteocalcin, and the development of a calcified matrix. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Preparation and characterization of trace elements‐multidoped injectable biomimetic materials for minimally invasive treatment of osteoporotic bone trauma
Authors: Yang Xianyan , Gan Yilai , Gao Xin , Zhao Li , Gao Changyou , Zhang Xinli , Feng Yanbo , Ting Kang , Gou Zhongru
Published: September 2010

It has always been a clinical challenge to use the proper implants or biomaterials to restore function to traumatized bone defects in patients with osteoporosis. In this study, we prepared the alginate–chitosan/trace elements‐multidoped octacalcium phosphate–bioglass (AT–CS/teOCP‐BG) hydrogel composite as an injectable biomaterial and evaluated its physicochemical properties and biological performance. Trace amount of silicon, strontium, and zinc was first doped into the structure of OCP porous microspheres via a wet chemical reaction. The AT–CS complex was mechanically mixed with teOCP and then neutralized by the ionic products of bioglass 58S particles dissolution. Formulations of this novel composite presented in wet state have teOCP‐BG contents ranging from 7.8 to 25.4% and AT–CS content of below 3.2%. The composite retained gel in culture medium at 37°C, and the ratio of storage modulus and loss modulus (G′/G″) exhibited a marked increase with decreasing the amount of BG, signifying a pH‐dependent enhancement of rheological properties and gel stability. After injection into rat femoral bone marrow cavity with minimal tissue invasion, new bone ingrowth was observed from radiologic images in the ovariectomized (OVXed) rats, which was significantly greater than that found in sham‐operated animals within 8 weeks postoperatively. The fast bone regeneration phenomenon was observed in the OVXed rats by radiographic and microcomputerized tomography examination and histological analysis. These findings suggest that the AT–CS/teOCP‐BG system might be used as an injectable biomaterial for minimally invasive treatment of osteoporosis‐related (micro‐)trauma. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Effect of crosslinking on the performance of a collagen‐derived biomaterial as an implant for soft tissue repair: A rodent model
Authors: de Castro Brás Lisandra E. , Proffitt Joanne L. , Bloor Steve , Sibbons Paul D.
Published: September 2010

One of the main problems in healthcare is the loss of tissues resulting from diseases, post‐surgery complications or trauma. As a result there is a need for biomaterials designed to promote tissue regeneration and improve wound healing. This study assessed the effect of crosslinking of a porcine dermal collagen matrix with regard to strength of implant/host tissue integration, implant biocompatibility and general healing in a rodent model. Permacol™, a crosslinked acellular collagenous biomaterial was compared with its noncrosslinked equivalent at 3, 6, and 12 months postsubcutaneous implantation. Both matrices were well tolerated and showed no evidence of inflammation or adverse responses either in the host tissue or implants. Progressive integration of the implants with the surrounding tissue was observed. Cellular response was similar for both collagenous matrices although, at 3 and 6 months, noncrosslinked implants showed a significantly higher level of cellular penetration than crosslinked implants. However, at 12 months crosslinked implants showed significantly higher levels of cellular density, neo‐vascularisation and integration with host tissue. Additionally, at long term, noncrosslinked implants lost volume suggesting some absorption. The crosslinking process does not seem to be detrimental to cellular response and biocompatibility. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Preparation and characterization of novel alkali‐activated nano silica cements for biomedical application
Authors: Lin Qing , Lan Xianghui , Li Yanbao , Ni Yaru , Lu Chunhua , Chen Yixin , Xu Zhongzi
Published: September 2010

The major goal of this study was to investigate and characterize novel Ca(OH)2‐activated nano silica (SiO2) cements for the potential application as a bone cement. Novel Ca(OH)2‐activated nano‐SiO2 powders composed of Ca(OH)2 and nano‐SiO2 were easily prepared, and the deionized water was used as the liquid phase. The initial and final setting times of Ca(OH)2‐activated nano‐SiO2 cements with liquid to powder (L/P) ratios of 1.00–1.33 mL g−1 range from 50 ± 1 to 120 ± 3 min and 96 ± 2 to 190 ± 5 min, respectively. The calorimetric curves indicate that the heat liberations of Ca(OH)2‐activated nano‐SiO2 cements (105.57–138.01 J g−1) are lower than that of C3S (about 150 J g−1). The Ca(OH)2‐activated nano‐SiO2 pastes are injectable under general extrusion force of 100 N, and their compressive strengths with suitable L/P ratios are 5–9 MPa, which is comparable with that of cancellous bone. The in vitro bioactivity of the Ca(OH)2‐activated nano‐SiO2 cement pastes were investigated by soaking in simulated body fluid for various periods. The results show amorphous apatite deposits on the paste surfaces after soaking in simulated body fluid for 2 h. With the prolonged soaking time, amorphous apatite transforms into crystalline apatite after soaking for 1 day. The Ca(OH)2‐activated nano‐SiO2 cements have short setting times, low heat liberation, injectability, suitable compressive strength, and excellent in vitro bioactivity, and may be used as bioactive bone cements for bone regeneration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Optimal selection of biological tissue using the energy dissipated in the first loading cycle
Authors: Rojo Francisco J. , Páez José M. García , Jorge‐Herrero Eduardo , Atienza José M. , Millán Isabel , Rocha Aurora , de Córdova Alfonso Hoyos Fernández , Guinea Gustavo V.
Published: September 2010

Calf pericardium, similar to that used in the manufacturing of prosthetic valve cusps, was fatigue tested. After six batches of 100 cycles of 1 MPa of loading pressure, half of the samples broke. The mean energy dissipated in the first cycle by the surviving samples was 0.16 J, which is lower than the 0.28 J dissipated by the specimens that broke (p = 0.005). The hysteresis of the first cycle was characteristic and different from the following ones and correlated superbly with fatigue resistance. Setting a threshold value for the energy of the first cycle of 0.20 J, the performance index (the percentage of true predictions) was almost 80%, and the area under the ROC curve was 0.823 (maximum value is 1). When including the mean thickness in the selection parameters, as an indirect measure of the specimen mass, the performance index grew over 95%, meaning that the error of the predictions was less than 5%. Combining both parameters in one, a high performance index is maintained at 87.5% and the area under the ROC curve increases to 0.917. This non‐destructive method should help optical methods in the process of selecting the most appropriate and homogenous biological material. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
An alginate hydrogel dura mater replacement for use with intracortical electrodes
Authors: Nunamaker Elizabeth A. , Kipke Daryl R.
Published: September 2010

The collagenous dura mater requires a secure closure following implantation of neural prosthetic devices to avoid complications due to cerebrospinal fluid leakage and infections. Alginate was previously suggested for use as a dural sealant. The liquid application and controllable gelling conditions enable alginate to conform to the unique geometries of a neural prosthetic device and the surrounding dura mater to create a barrier with the external environment. In this study, we evaluated the use of alginate as a method to securely reclose a dural defect and seal around an untethered microscale neural probe in the rabbit model. After 3 days and 3 weeks, the sealing strength of alginate remained eight times greater than normal rabbit intracranial pressure and similar in both the presence and absence of a penetrating neural probe. For time points up to 3 months, there was no significant difference in dura mater fibrosis or thickness between alginate and controls. Application of alginate to a dural defect results in a watertight seal that remains intact while the dura mater reforms. These findings indicate that alginate is an effective tool for sealing around microscale neural probes and suggests broader application as a sealant for larger neural prosthetic devices. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Simple method to prepare size‐controllable gold nanoparticles in solutions and their applications on surface‐enhanced Raman scattering
Authors: Yu Chung‐Chin , Liu Yu‐Chuan , Yang Kuang‐Hsuan , Tsai Hui‐Yen
Published: September 2010

We report here, for the first time, a simple method to prepare size‐controllable Au nanoparticles (NPs) in aqueous solutions from bulk Au substrates. First, chitosan (Ch)‐capped Au‐containing complexes were prepared by electrochemical oxidation–reduction cycles in 0.1 N NaCl and 1 g/l Ch solutions. Then the solutions were heated from room temperature to boiling at different heating rates to synthesize size‐controllable Au NPs. The particle sizes of the prepared Au(111) NPs could be controlled from 5 to 30 nm with an increase of the heating rate during preparation. Experimental results indicate that the prepared Au(111) NPs with diameters ranging from 10 to 30 nm can serve as surface‐enhanced Raman scattering active probes for molecules of rhodamine 6G. Copyright © 2010 John Wiley & Sons, Ltd.
Short‐time photodecay dynamics of meso‐tetra(p‐hydroxyphenyl)porphine in the condensed phase explored via resonance Raman spectroscopy and density functional theory calculation
Authors: Wu Zhangzhu , Xu Jun , Wan Junmin , Zheng Xuming , Wang Huigang , Tan Yao
Published: September 2010

Resonance Raman (RR) spectra of free‐base meso‐tetra(p‐hydroxyphenyl)porphine(THPP) were obtained with 397.9, 416 and 514 nm excitation wavelengths, and density functional calculations were carried out to help the elucidation of the photorelaxation dynamics of Soret (Bx and By bands) electronic transitions and the RR spectra of THPP. The RR spectrum indicates that the Franck–Condon (FC) region photorelaxation dynamics for the S0 → S5 excited electronic state is predominantly along the totally symmetric CmphC stretching and the CβCβ stretchingand simultaneously along the asymmetric (CmCα)as stretching, ν(phCC)asstretching, δ(NH)s and γ(CβH) vibrational relaxation processes, while that for S0 → S4 electronic state is predominantly along the CmphC stretching and pyrrole breathing. The excited‐state structural dynamics of THPP determined from the RR spectra shows that internal conversion (IC) By → Bx electronic relaxation occurs in tens of femtoseconds, and the short‐time dynamics is interpreted using the time‐dependent wave packet theory and Herzberg–Teller (vibronic coupling) contributions. Copyright © 2010 John Wiley & Sons, Ltd.
High‐Performance Polybenzoxazine Nanocomposites Containing Multifunctional POSS Cores Presenting Vinyl‐Terminated Benzoxazine Groups
Authors: Huang Kai‐Wei , Kuo Shiao‐Wei
Published: September 2010

We have prepared a new class of polybenzoxazine/POSS nanocomposites through the reactions of a multifunctional vinyl‐terminated VBa‐POSS with a VBa monomer at various compositional ratios. The incorporation of the silsesquioxane core units into the polybenzoxazine matrix significantly hindered the mobility of the polymer chains and enhanced the thermal stability of these hybrid materials. Increasing the POSS content in these hybrids improved their thermal and mechanical properties, relative to those of the neat polybenzoxazine, because of hydrogen bonding between the siloxane groups of the POSS core units and the OH groups of the polybenzoxazine moieties, as adjudged using FTIR spectroscopy.

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Synthesis of Tung‐Oil‐Based Reactive Diluents
Authors: Wutticharoenwong Kosin , Soucek Mark D.
Published: September 2010

Three new reactive diluents were prepared from tung oil using a Diels‐Alder reaction. The dienophiles were methacryloxypropyl trimethoxysilane (MAS), 2,2,2‐trifluoroethyl methacrylate (TFM) and triallyl ether acrylate (TAEA). The chemical structures were evaluated using 1H NMR, 13C NMR, FT‐IR, GPC and MALDI‐TOF‐MS. Spectra evidence (NMR, MS) indicated that a six‐member ring were formed in all three reactions indicating a Diels‐Alder adduct. The reactive diluents were formulated with a soya‐based alkyd to evaluate viscosity reduction and drying time. The viscosity of alkyd was reduced up to 70% using the reactive diluents. The drying time for the autoxidative reactive diluents with alkyds were 1.8‐1‐7 times faster than alkyd alone.

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Responsive Hybrid Polymeric/Metallic Nanoparticles for Catalytic Applications
Authors: Zhang Jian‐Tao , Wei Gang , Keller Thomas F. , Gallagher Hilary , Stötzel Christian , Müller Frank A. , Gottschaldt Michael , Schubert Ulrich S. , Jandt Klaus D.
Published: September 2010

The aims of the current study were to synthesize new responsive polymeric microgels with embedded silver nanoparticles and then to employ these particles as catalyst for reduction reactions. To these ends, stimuli‐responsive microgels from PNIPAAm and the chitosan derivative were firstly synthesized by free radical precipitation polymerization. Then, silver nanoparticles were synthesized inside these microgel networks by in situ reduction of AgNO3. These microgels were temperature/pH sensitive with a phase transition temperature of 32–35 °C in water at pH = 3 and 8, respectively. The catalytic activity of the Ag nanoparticles for the reduction of 4‐nitrophenol can be tuned through the swelling or collapse of the responsive microgel network hosting the active nanoparticles.

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Synthesis of Organosilane‐Modified Carbon Nanofibers and Influence of Silane Coating Thickness on the Performance of Polyethylene Nanocomposites
Authors: Wood Weston , Kumar Sandeep , Zhong Wei‐Hong
Published: September 2010

Silane coatings with different thicknesses were synthesized on CNFs for reinforcement of polyethylene composites. The thickness of the silane coating was adjusted by using a basic catalyst to increase the overall reactivity of the silane groups, resulting in a thick coating of ≈46 nm (ca. 90% increase in fiber diameter). DMA performed on the polyethylene composites showed a substantial increase in storage modulus from 1.68 to 2.34 GPa (40%) at low temperatures in the composite with the thick silane coating (≈46 nm) at a low loading of 0.4 wt.‐%. We believe that the silane‐treated nanofillers with thick coatings are very promising for high‐performance nanocomposites with non‐polar polymer matrices.

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Folding of Polyalanine into Helical Hairpins
Authors: Palenčár Peter , Bleha Tomáš
Published: September 2010

The variation of the secondary structure and dimensions of long PA peptides was examined by means of all‐atom MD simulations. It was found that on cooling, instead of straight helices, hairpin‐like structures with two and three parallel helical legs were formed. The exclusive population of hairpins in PA at room temperature was proved by the bimodality of the distribution functions of the end‐to‐end distance and the radius of gyration. The helix‐turn‐helix motif revealed in PA simulations is pertinent for the structure of transmembrane proteins. The potential energy analysis showed a crucial role of the van der Waals forces in stabilization of the hairpins. It was underlined that this is a feature shared with folding of hydrocarbon chains, such as PE, into the crystal lamellae.

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Current Awareness in NMR in Biomedicine
Authors:   John Wiley & Sons, Ltd.
Published: September 2010

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 12 sections: 1 Reviews; 2 General; 3 Technology; 4 Contrast Agents; 5 Brain and Nerves; 6 Neuropathology; 7 Cancer; 8 Cardiac, Vascular and Respiratory Systems; 9 Liver, Kidney and Other Organs; 10 Muscle and Orthopaedic; 11 Plants, Micro‐organisms and Parasites; 12 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
Condition number bounds and mesh quality
Authors: Branets L. , Carey G. F.
Published: September 2010

We analyze the effect of mesh distortion on the condition number of the representative mass matrix M and stiffness matrix K arising in a typical finite element scheme. Bounds are stated for the respective condition numbers in terms of the Jacobian of the map from a reference element. These results are then used to construct the related bounds in terms of representative metrics for mesh distortion. These bounds are easily pre‐computable and provide a new explicit mathematical relation between matrix conditioning and mesh quality metrics. Numerical studies for a 2D test problem using a representative cell quality metric demonstrate the upper bound property and the dependence on cell quality for a quadrilateral cell. Analogous results for a 3D test problem under progressive symmetric mesh distortion of an interior hexahedral cell are also provided, as well as a study on a complex 3D geometry. We conclude by presenting practical adaptive mesh grading applications employing aforementioned mesh quality metrics. Copyright © 2010 John Wiley & Sons, Ltd.
An enhanced energy conserving time stepping algorithm for frictionless particle contacts
Authors: Bravo R. , Pérez‐Aparicio J. L. , Laursen T. A.
Published: September 2010

An Enhanced Energy Conserving Algorithm (EECA) formulation for time integration of frictionless contact–impact problems is presented. In it the energy, linear and angular momentum are conserved for every contact using an enhanced Penalty method. Previous formulations for these problems have shown that the total bodies' energy decreases for contact due to an artificial energy transfer between the penalty spring and the contacting bodies. Consequently, they are not able to reproduce a physical response after a single contact, introducing errors in trajectories and velocities.

Through the conserving balance equations, EECA computes a physical response by inserting for every contact an additional amount of linear momentum and contact force. The structure of these equations defines the additional linear momentum to restore the energy and the enhanced Penalty method based on a spring and a dashpot. This method approximately enforces the first and second Kuhn–Tucker conditions.

The new algorithm has been applied to several frictionless rigid problems using the Discrete Element Method. The first two problems consist of the simulation and analytical comparison of the Newton's Cradle and Carom problems (billiard pool problem). The last two are the hopper filling process and the breaking of a pool ball's triangular arrangement, both of which involve a medium number of contacts. Application of this formulation will be straightforward to elastic and general‐shaped bodies using the Finite Element Method. Copyright © 2010 John Wiley & Sons, Ltd.
A simple multi‐directional absorbing layer method to simulate elastic wave propagation in unbounded domains
Authors: Semblat Jean‐François , Lenti Luca , Gandomzadeh Ali
Published: September 2010

The numerical analysis of elastic wave propagation in unbounded media may be difficult due to spurious waves reflected at the model artificial boundaries. This point is critical for the analysis of wave propagation in heterogeneous or layered solids. Various techniques such as Absorbing Boundary Conditions, infinite elements or Absorbing Boundary Layers (e.g. Perfectly Matched Layers) lead to an important reduction of such spurious reflections. In this paper, a simple absorbing layer method is proposed: it is based on a Rayleigh/Caughey damping formulation which is often already available in existing Finite Element softwares. The principle of the Caughey Absorbing Layer Method is first presented (including a rheological interpretation). The efficiency of the method is then shown through 1D Finite Element simulations considering homogeneous and heterogeneous damping in the absorbing layer. 2D models are considered afterwards to assess the efficiency of the absorbing layer method for various wave types and incidences. A comparison with the PML method is first performed for pure P‐waves and the method is shown to be reliable in a more complex 2D case involving various wave types and incidences. It may thus be used for various types of problems involving elastic waves (e.g. machine vibrations, seismic waves, etc.). Copyright © 2010 John Wiley & Sons, Ltd.
Control of modeling error in calibration and validation processes for predictive stochastic models
Authors: Oden J. Tinsley , Prudhomme Serge
Published: September 2010

The idea of adaptive control of modeling error is expanded to include ideas of statistical calibration, validation, and uncertainty quantification. Copyright © 2010 John Wiley & Sons, Ltd.
Worst‐case analysis of distributed parameter systems with application to the 2D reaction–diffusion equation
Authors: Kishida Masako , Braatz Richard D.
Published: September 2010

It is well known that optimal control trajectories can be highly sensitive to perturbations in the model parameters. Computationally efficient numerical algorithms are presented for the worst‐case analysis of the effects of parametric uncertainties on boundary control problems for finite‐time distributed parameter systems. The approach is based on replacing the full‐order model of the system with a power series expansion that is analyzed by linear matrix inequalities or power iteration, which are polynomial‐time algorithms. Theory and algorithms are provided for computing the most positive and most negative worst‐case deviation in a state or output, in contrast to the ‘two‐sided’ deviations normally computed in worst‐case analyses. Application to the Dirichlet boundary control of the reaction–diffusion equation to track a desired two‐dimensional concentration field illustrates the promise of the approach. Copyright © 2010 John Wiley & Sons, Ltd.
Optimal control of the atmospheric reentry of a space shuttle by an homotopy method
Authors: Hermant Audrey
Published: September 2010

This paper deals with the optimal control problem of the atmospheric reentry of a space shuttle with a second‐order state constraint on the thermal flux. We solve the problem using the shooting algorithm combined with an homotopy method, which automatically determines the structure of the optimal trajectory (composed of one boundary arc and one touch point). Copyright © 2010 John Wiley & Sons, Ltd.
Photovoltaics literature survey (No. 81)
Authors: Shrestha Santosh
Published: September 2010

In order to help keep readers up‐to‐date in the field each issue of Progress in Photovoltaics will contain a list of recently published journal articles most relevant to its aims and scope. This list is drawn from an extremely wide range of journals, including IEEE Transactions on Electron Devices, Journal of Applied Physics, Applied Physics Letters, Progress in Photovoltaics and Solar Energy Materials and Solar Cells. To assist the reader, the list is separated into broad categories, but please note that these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions please email Santosh Shrestha at s.shrestha@unsw.edu.au.
Hydrogen abstraction from H‐donor substrates by the 6‐CF3‐benzotriazol‐N‐oxyl radical (TFNO)
Authors: Tadesse Mahelet Aweke , Galli Carlo , Gentili Patrizia
Published: September 2010

The aminoxyl radical 6‐trifluoromethyl‐benzotriazol‐N‐oxyl (TFNO) has been generated from the parent hydroxylamine 6‐CF3‐1‐hydroxy‐benzotriazole (TFBT) by one‐electron oxidation with a CeIV salt and characterized by spectrophotometry and cyclic voltammetry (CV). Rate constants of H‐abstraction (kH) by TFNO from a number of H‐donor benzylic substrates have been determined spectrophotometrically in MeCN solution at 25 °C. A radical H‐atom transfer (HAT) route of oxidation is substantiated for TFNO by several pieces of evidence. The kinetic data also testify the relevance of stereoelectronic effects upon the HAT reactivity of TFNO. Copyright © 2010 John Wiley & Sons, Ltd.
Application of activation hardness in perturbed pericyclic reactions: a case study involving electrocyclic ring opening reactions of heterocyclobutenes
Authors: Jaccob M. , Sheeba Jem I. , Giri Santanab , Venuvanalingam P. , Chattaraj P. K.
Published: September 2010

Cyclobutene undergoes electrocyclic ring opening through conrotatory mode to give 1,3‐butadiene and similarly its skeletally substituted analogues viz. phosphetene, thietene, oxetene and azetene isomerize to give their respective heterodienes. Quantum mechanical investigations on these perturbed pericyclic isomerizations at B3LYP level with 6‐31G(d) and 6‐311 + G(d,p) basis sets reveal that hetero ‐ atoms significantly lower the barrier and alter the reaction free energies. Interestingly frontier orbital correlation diagram shows that σ and σ* levels are perturbed significantly while π and π* levels undergo little changes during the reaction; the lone pairs on hetero – atoms are slightly stabilized in the TS. This results in σ becoming HOMO in the TSs of phosphetene and thietene isomerizations and σ* becoming LUMO in all the cases. This necessitates defining hardness values based on closely interacting frontier orbitals for reactants and TSs and use them to compute activation hardness values to interpret relative reactivity. Copyright © 2010 John Wiley & Sons, Ltd.