bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a comprehensive mathematical model for free radical suspension polymerization of methyl methacrylate
Authors: Verros George D. , Achilias Dimitris S. , Giannoukos Georgios I.
Published: December 2010

In this work a detailed mathematical model for free radical suspension polymerization of methyl methacrylate (MMA) in water is developed. This model is based on sound principles such as the free volume theory to account for the diffusion limited reactions in suspension polymerization. Additionally, the complex polymerization kinetics process of the aqueous suspension polymerization of MMA is studied as a one‐dimensional numerical experiment. For this purpose, the polymerization process is modeled as a moving boundary mass transfer problem coupled with polymerization reactions. The Galerkin finite element method is used to simultaneously solve the nonlinear governing equations. The model predictions for conversion and average molecular weights vs. time were found to be in close agreement with laboratory data. It is believed that this work, as it provides fundamental understanding of the process, it might contribute to a more rational design of polymerization reactors. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Ultradrawing properties of ultra‐high molecular weight polyethylene/functionalized carbon nanotube fibers
Authors: Yeh Jen‐Taut , Wu Tsong‐Wei , Lai Yu‐Ching , Zhou Huo‐Peng , Zhou Qin , Li Qi‐Cheng , Wen Sheng , Tsai Fang‐Chang , Huang Chi‐Yuan , Huang Kuo‐Shien , Chen Kan‐Nan
Published: December 2010

Systemic investigation of the influence of the plain and functionalized carbon nanotube (CNT) contents on the ultradrawing properties of ultrahigh molecular weight polyethylene/carbon nanotubes (UHMWPE/CNTs, FCy) and UHMWPE/functionalized CNTs (FCfx‐y) as‐prepared fibers are reported. In a way similar to those found for the orientation factor values, the achievable draw ratios (Dra) of the FCy and FCfx‐y as‐prepared fibers approached a maximum value as their CNT and/or functionalized CNT contents reached their corresponding optimum values. The maximum Dra values obtained for FCfx‐0.001 as‐prepared fiber specimens prepared at varying maleic anhydride grafted polyethylene (PE‐g‐MAH)/modified CNTs weight ratios were significantly higher that of the FC0.0015 as‐prepared fiber specimen prepared at the optimum plain CNT content. Tensile property analysis further suggested that excellent orientation and tensile properties of the drawn FCy and FCfx‐y fibers can be obtained by ultradrawing the fibers prepared at their optimum plain CNT and/or functionalized CNT contents. To understand the interesting orientation, ultradrawing and tensile properties of FCy and FCfx‐y fiber specimens, FTIR, specific surface area, and SEM morphology analysis of the plain and functionalized CNTs were performed in this study. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Analysis of solution polybutadiene polymerizations performed with a neodymium catalyst
Authors: Ferreira Luis Carlos , de Santa Maria Luiz Claudio , Costa Marcos A.S. , Pires Neusa Maria Tochetto , Nele Marcio , Pinto José Carlos
Published: December 2010

This article is regarding the polymerization of 1,3‐butadiene with a neodymium catalyst activated by diisobutylaluminum‐hydride and diethylaluminum chloride (DEAC). The effects of the polymerization conditions (ratio between DEAC and neodymium molar concentrations, polymerization temperature, catalyst concentration, and butadiene concentration) on the polymer yield and molecular weight distribution (MWD) of polybutadiene (PB) samples were evaluated. It is shown that the DEAC/Nd ratio and the polymerization temperature are the reaction variables that influence the MWD and the catalyst performance most significantly. PBs with broad and sometimes bimodal MWD were produced at the analyzed reaction conditions. For this reason, the MWD of the obtained polymer materials was deconvoluted with the help of the Flory most probable distribution, indicating that three or more catalyst sites are required to explain the final MWD of the polymer samples. Finally, it was observed that the analyzed neodymium catalyst is able to produce branched PBs at mild reaction conditions and that the branching frequency depends on the polymerization conditions, which may be useful for development of operation policies at plant site and production of materials with improved performances. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Knowledge Maturity as a Means to Support Decision Making during Product-Service Systems Development Projects in the Aerospace Sector
Authors: Johansson Christian , Hicks Ben , Larsson Andreas C. , Bertoni Marco
Published: December 2010

Streamlining new product development forces companies to make decisions on preliminary information. This article considers this challenge within the context of project management in the aerospace sector and, in particular, for the development of product-service systems. The concept of knowledge maturity is explored as a means to provide practical decision support, which increases decision makers’ awareness of the knowledge base and supports cross-boundary discussions on the perceived maturity of available knowledge, thereby identifying and mitigating limitations. Requirements are elicited from previous research on knowledge maturity in the aerospace industry, and a knowledge maturity model is developed through five industry-based workshops.
Inhalation aromatherapy in children and adolescents undergoing stem cell infusion: results of a placebo‐controlled double‐blind trial
Authors: Ndao Deborah H. , Ladas Elena J. , Cheng Bin , Sands Stephen A. , Snyder Kathryn T. , Garvin James H. , Kelly Kara M.
Published: December 2010

Objective: Though often lifesaving, stem cell transplantation (SCT) is a period of great distress for both child and parent.

Methods: We conducted a double‐blind, placebo‐controlled randomized study evaluating the effect of the respiratory administration of bergamot essential oil on the anxiety, nausea, and pain of37pediatric patients with malignant and non‐malignant disorders undergoing stem cell infusion and their parents. Patients were assessed at the time of recruitment, prior to infusion, upon infusion completion, and one hour post‐infusion using the Spielberger State‐Trait Anxiety Inventory (STAI) for parents and the STAIC, Children's Behavioral Style Scale (CBSS), visual analogue scale (VAS) for pain and nausea, and the Emotionality Activity Sociability and Impulsivity instrument (EASI) for children.

Results: Children and adolescents in the treatment group experienced greater anxiety (p= 0.05) and nausea (p= 0.03) one hour post‐infusion. Reported pain in both groups was no longer significant one hour post‐infusion. Parental anxiety declined in both groups but did not reach statistical significance. Child's monitoring coping style was significantly predictive of transitory anxiety post‐infusion (p= 0.01).

Conclusions: Although this trial did not report a benefit of inhalation aromatherapy for reducing anxiety, nausea, or pain when added to standard supportive care, it provides the first experimental rather than descriptive report on testing a single therapeutic essential oil among children and adolescents undergoing stem cell infusion. Future research may consider exploring the cutaneous application of essential oil through massage or other psychoeducational counseling interventions among parents with elevated anxiety and patients with greater information seeking coping styles during SCT. Copyright © 2010 John Wiley & Sons, Ltd.
Regulation of androgen receptor expression through angiotensin II type 1 receptor in prostate cancer cells
Authors: Hoshino Koji , Ishiguro Hitoshi , Teranishi Jun‐ichi , Yoshida Shin‐ichiro , Umemura Satoshi , Kubota Yoshinobu , Uemura Hiroji
Published: December 2010

BACKGROUND

Although the local renin‐angiotensin system (RAS) of the prostate gland is related to cell proliferation and angiogenesis, the detailed mechanism remains unclear. We examined the effects of the angiotensin II type 1 receptor (AT1R) on androgen receptor (AR) expression in prostate cancer cells.

METHODS

AR modulation by AT1R was examined by Western blot analysis, luciferase assay, and Immunocytochemical staining. The influence of AR expression by angiotensin II (Ang‐II) and AT1R inhibition using siRNA was determined. Furthermore, using angiotensinogen or AT1R knockout (KO) mice, we performed quantitative real‐time PCR to investigate the expression of AR.

RESULTS

Ang‐II induced cell proliferation with enhancement of AR, prostate specific antigen (PSA), NF‐κB, and c‐myc, and the activity of AR and PSA promoter. Cell proliferation of LNCaP transfected with AT1R siRNA was decreased by 75% at 7 days by inhibition of AR, PSA, NF‐κB, and c‐myc. Immunocytochemical staining confirmed the suppression of AR translocation into the nucleus in AT1R siRNA cells. AT1R KO mice showed a decrease in AR expression in the prostate gland. We also found that the expression level of AT1R could modulate the transcriptional level of AR by affecting NF‐κB and c‐myc expression.

CONCLUSIONS

Knocking down of the AT1R protein resulted in significant inhibition of cell growth, associated with a marked decrease of AR protein. These results indicate that inhibition of AT1R has the potential to influence AR expression in prostate cells, and is anticipated to contribute to the development of novel therapeutic agents for prostate cancer. Prostate 71: 964–975, 2011. © 2010 Wiley‐Liss, Inc.
Disparities at presentation, diagnosis, treatment, and survival in African American men, affected by prostate cancer
Authors: Chornokur Ganna , Dalton Kyle , Borysova Meghan E. , Kumar Nagi B.
Published: December 2010

BACKGROUND

Prostate cancer (PCa) remains the most common malignancy and the second leading cause of cancer death among men in the United States. PCa exhibits the most striking racial disparity, as African American men are at 1.4 times higher risk of being diagnosed, and 2–3 times higher risk of dying of PCa, compared to Caucasian men. The etiology of the disparity has not been clearly elucidated. The objective of this article is to critically review the literature and summarize the most prominent PCa racial disparities accompanied by proposed explanations.

METHODS

The present literature on disparities at presentation, diagnosis, treatment, and survival of African American men affected by PCa was systematically reviewed. Original research as well as relevant review articles were included.

RESULTS

African American men persistently present with more advanced disease than Caucasian men, are administered different treatment regimens than Caucasian men, and have shorter progression‐free survival following treatment. In addition, African American men report more treatment‐related side‐effects that translates to the diminished quality of life (QOL).

CONCLUSIONS

PCa racial disparity exists at stages of presentation, diagnosis, treatment regimens, and subsequent survival, and the QOL. The disparities are complex involving biological, socio‐economic, and socio‐cultural determinants. These mounting results highlight an urgent need for future clinical, scientific, and socio‐cultural research involving transdisciplinary teams to elucidate the causes for PCa racial disparities. Prostate 71: 985–997, 2011. © 2010 Wiley‐Liss, Inc.
5α‐reductase type 3 expression in human benign and malignant tissues: A comparative analysis during prostate cancer progression
Authors: Godoy Alejandro , Kawinski Elzbieta , Li Yun , Oka Daizo , Alexiev Borislav , Azzouni Faris , Titus Mark A. , Mohler James L.
Published: December 2010

BACKGROUND

A third isozyme of human 5α‐steroid reductase, 5α‐reductase‐3, was identified in prostate tissue at the mRNA level. However, the levels of 5α‐reductase‐3 protein expression and its cellular localization in human tissues remain unknown.

METHODS

A specific monoclonal antibody was developed, validated, and used to characterize for the first time the expression of 5α‐reductase‐3 protein in 18 benign and 26 malignant human tissue types using immunostaining analyses.

RESULTS AND CONCLUSIONS

In benign tissues, 5α‐reductase‐3 immunostaining was high in conventional androgen‐regulated human tissues, such as skeletal muscle and prostate. However, high levels of expression also were observed in non‐conventional androgen‐regulated tissues, which suggest either multiples target tissues for androgens or different functions of 5α‐reductase‐3 among human tissues. In malignant tissues, 5α‐reductase‐3 immunostaining was ubiquitous but particularly over‐expressed in some cancers compared to their benign counterparts, which suggests a potential role for 5α‐reductase‐3 as a biomarker of malignancy. In benign prostate, 5α‐reductase‐3 immunostaining was localized to basal epithelial cells, with no immunostaining observed in secretory/luminal epithelial cells. In high‐grade prostatic intraepithelial neoplasia (HGPIN), 5α‐reductase‐3 immunostaining was localized in both basal epithelial cells and neoplastic epithelial cells characteristic of HGPIN. In androgen‐stimulated and castration‐recurrent prostate cancer (CaP), 5α‐reductase‐3 immunostaining was present in most epithelial cells and at similar levels, and at levels higher than observed in benign prostate. Analyses of expression and functionality of 5α‐reductase‐3 in human tissues may prove useful for development of treatment for benign prostatic enlargement and prevention and treatment of CaP. Prostate 71:1033–1046, 2011. © 2010 Wiley‐Liss, Inc.
Expression of semenogelins I and II and its prognostic significance in human prostate cancer
Authors: Canacci Anastasia M. , Izumi Koji , Zheng Yichun , Gordetsky Jennifer , Yao Jorge L. , Miyamoto Hiroshi
Published: December 2010

BACKGROUND

Little is known about the role of semenogelins, seminal plasma proteins that play critical roles in semen clotting and subsequent liquefaction in the presence of zinc and prostate‐specific antigen, in human malignancies.

METHODS

We investigated the expression of semenogelins in four human prostate cancer lines by RT‐PCR and Western blotting as well as in 70 radical prostatectomy specimens by immunohistochemistry. Effects of semenogelin overexpression on prostate cancer cell proliferation were also assessed.

RESULTS

mRNA/protein signals for semenogelins I (SgI) and II (SgII) were detected only in androgen‐sensitive LNCaP cells cultured with zinc. Transfection of SgI/SgII increased/decreased cell growth of androgen receptor (AR)‐positive/semenogelin‐negative CWR22Rv1 in the presence of zinc, whereas it showed marginal effects in AR‐negative/semenogelin‐negative PC‐3 and DU145. Immunohistochemical studies showed that SgI and SgII stain positively in 55 (79%) and 31 (44%) cancer tissues, respectively, which was significantly higher than in corresponding benign tissues [SgI‐positive in 13 (19%) cases (P < 0.0001) and SgII‐positive in 15 (21%) cases (P = 0.0066)]. Among the histopathological parameters available for our patient cohort, there was an inverse association only between Gleason score (GS) and SgII expression (GS ≤ 7 vs. GS ≥ 8: P = 0.0150; GS7 vs. GS ≥ 8: P = 0.0111). Kaplan–Meier and log‐rank tests further revealed that patients with SgI‐positive/SgII‐negative tumor have the highest risk for biochemical recurrence (P = 0.0242).

CONCLUSIONS

These results suggest the involvement of semenogelins in prostate cancer and their prognostic values in predicting cancer progression after radical prostatectomy. Additional functional analyses of semenogelins are necessary to determine their biological significance in prostate cancer. Prostate 71:1108–1114, 2011. © 2010 Wiley‐Liss, Inc.
Bioinspired peptide nanotubes: deposition technology, basic physics and nanotechnology applications
Authors: Rosenman G. , Beker P. , Koren I. , Yevnin M. , Bank‐Srour B. , Mishina E. , Semin S.
Published: December 2010

Synthetic peptide monomers can self‐assemble into PNM such as nanotubes, nanospheres, hydrogels, etc. which represent a novel class of nanomaterials. Molecular recognition processes lead to the formation of supramolecular PNM ensembles containing crystalline building blocks. Such low‐dimensional highly ordered regions create a new physical situation and provide unique physical properties based on electron‐hole QC phenomena. In the case of asymmetrical crystalline structure, basic physical phenomena such as linear electro‐optic, piezoelectric, and nonlinear optical effects, described by tensors of the odd rank, should be explored. Some of the PNM crystalline structures permit the existence of spontaneous electrical polarization and observation of ferroelectricity. The PNM crystalline arrangement creates highly porous nanotubes when various residues are packed into structural network with specific wettability and electrochemical properties.

We report in this review on a wide research of PNM intrinsic physical properties, their electronic and optical properties related to QC effect, unique SHG, piezoelectricity and ferroelectric spontaneous polarization observed in PNT due to their asymmetric structure. We also describe PNM wettability phenomenon based on their nanoporous structure and its influence on electrochemical properties in PNM.

The new bottom‐up large scale technology of PNT physical vapor deposition and patterning combined with found physical effects at nanoscale, developed by us, opens the avenue for emerging nanotechnology applications of PNM in novel fields of nanophotonics, nanopiezotronics and energy storage devices. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Photocurrent generation through peptide‐based self‐assembled monolayers on a gold surface: antenna and junction effects
Authors: Gatto Emanuela , Caruso Mario , Porchetta Alessandro , Toniolo Claudio , Formaggio Fernando , Crisma Marco , Venanzi Mariano
Published: December 2010

The photocurrent generation properties of mono‐ and bi‐component peptide‐based self‐assembled monolayers (SAMs) immobilized on a gold surface were studied by electrochemical and spectroscopic techniques. The peptides investigated comprised almost exclusively Cα‐tetrasubstituted α‐amino acids. These non‐coded residues, because of their unique conformational properties, forced the peptide backbone to attain a helical conformation, as confirmed by X‐ray crystal structure and CD determinations in solution. The peptide helical structure promoted the formation of a stable SAM on the gold surface, characterized by an electric macrodipole directed from the C(δ−) to the N(δ+) terminus, that remarkably affected the electron transfer (ET) process through the peptide chain. The peptides investigated were derivatized with chromophores strongly absorbing in the UV region to enhance the efficiency of the photocurrent generation (antenna effect). The influence of the nature of the peptide–gold interface on the ET process (junction effect) was analyzed by comparing the photocurrent generation process in peptide SAMs immobilized on a gold surface through AuS linkages with that in a bi‐component SAM embedding a photoactive peptide into the linked palisade formed by disulfide‐functionalized peptides. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
De novo design of orthogonal peptide pairs forming parallel coiled‐coil heterodimers
Authors: Gradišar Helena , Jerala Roman
Published: December 2010

We used the principles governing the selectivity and stability of coiled‐coil segments to design and experimentally test a set of four pairs of parallel coiled‐coil‐forming peptides composed of four heptad repeats. The design was based on maximizing the difference in stability between desired pairs and the most stable unwanted combinations using N‐terminal helix initiator residues, favorable combinations of the electrostatic and hydrophobic interaction motifs and negative design motif based on burial of asparagine residues. Experimental analysis of all 36 pair combinations among the eight peptides was performed by circular dichroism (CD). On the basis of CD spectra, each peptide formed a high level of α‐helical structure exclusively in combination with its designed peptide partner which demonstrates the orthogonality of the designed peptide pair set. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Synthesis and self‐assembly of a neoglycopeptide: morphological studies and ultrasound‐mediated DNA encapsulation
Authors: Gour Nidhi , Mondal Sudipta , Verma Sandeep
Published: December 2010

Self‐assembly in peptides and proteins is an often encountered concept, where constituent building blocks are recruited and stabilized, via carefully orchestrated hydrophobic interactions, hydrogen bonding and other non‐covalent interactions, to eventually reveal an array of supramolecular aggregates, with defined structural features. This study presents synthesis and self‐assembly of a mannosylated peptide in aqueous medium. Turbidimetric assay with Concanavalin A (Con A), a mannose binding protein, was conducted to confirm the presence of hydrophilic mannose group on the exterior surface of self‐assembled structures. DNA encapsulation in these soft structures was achieved by ultrasonication of soft spherical structures in the presence of plasmid DNA. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Self‐assembly of amphiphilic β‐sheet peptide tapes based on aliphatic side chains
Authors: Davies Robert Philip Wynn , Aggeli Amalia
Published: December 2010

Amphiphilic β‐sheet nanotapes based on the self‐assembly of 9mer and 7mer de novo designed β‐strand peptides were studied in the dilute regime. The hydrophobic face of the tapes consisted predominantly of aliphatic (leucine) side chains, while the hydrophilic tape face contained polar side chains (glutamine, arginine and glutamic acid). Both peptides underwent a transition from a monomeric random coil to a self‐assembled β‐sheet tape upon increase of peptide concentration in aqueous solutions. P9‐6 exhibited lower critical concentration (c*) for self‐assembly and thus higher propensity for self‐assembly in water, compared to the shorter P7‐6. At neutral pH where there was little net charge per peptide, self‐assembly was favoured compared to low pH in which there was a net + 1 charge per peptide; the net charge decreased overall intermolecular attraction, manifested as an increase in c* for self‐assembly in low compared to neutral pH aqueous solutions. Propensity for self‐assembly and β‐sheet formation was found to be greatly enhanced in a polar organic solvent (methanol) compared to water. These studies combined with future more extensive comparative studies between amphiphilic tapes based on aliphatic amino acid residues and amphiphilic tapes based on aromatic residues will throw more light on the relative importance of hydrophobic versus aromatic interactions for the stabilisation of peptide assemblies. Systematic studies of this kind may also allow us to throw light on the fundamental principles that drive peptide self‐assembly and β‐sheet formation; they may also lead to a set of refined criteria for the effective design of peptides with prescribed combination of properties appropriate for specific applications. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Sequential methods for random‐effects meta‐analysis
Authors: Higgins Julian P. T. , Whitehead Anne , Simmonds Mark
Published: December 2010

Although meta‐analyses are typically viewed as retrospective activities, they are increasingly being applied prospectively to provide up‐to‐date evidence on specific research questions. When meta‐analyses are updated account should be taken of the possibility of false‐positive findings due to repeated significance tests. We discuss the use of sequential methods for meta‐analyses that incorporate random effects to allow for heterogeneity across studies. We propose a method that uses an approximate semi‐Bayes procedure to update evidence on the among‐study variance, starting with an informative prior distribution that might be based on findings from previous meta‐analyses. We compare our methods with other approaches, including the traditional method of cumulative meta‐analysis, in a simulation study and observe that it has Type I and Type II error rates close to the nominal level. We illustrate the method using an example in the treatment of bleeding peptic ulcers. Copyright © 2010 John Wiley & Sons, Ltd.
Estimating propensity scores with missing covariate data using general location mixture models
Authors: Mitra Robin , Reiter Jerome P.
Published: December 2010

In many observational studies, analysts estimate causal effects using propensity scores, e.g. by matching, sub‐classifying, or inverse probability weighting based on the scores. Estimation of propensity scores is complicated when some values of the covariates are missing. Analysts can use multiple imputation to create completed data sets from which propensity scores can be estimated. We propose a general location mixture model for imputations that assumes that the control units are a latent mixture of (i) units whose covariates are drawn from the same distributions as the treated units' covariates and (ii) units whose covariates are drawn from different distributions. This formulation reduces the influence of control units outside the treated units' region of the covariate space on the estimation of parameters in the imputation model, which can result in more plausible imputations. In turn, this can result in more reliable estimates of propensity scores and better balance in the true covariate distributions when matching or sub‐classifying. We illustrate the benefits of the latent class modeling approach with simulations and with an observational study of the effect of breast feeding on children's cognitive abilities. Copyright © 2010 John Wiley & Sons, Ltd.
Two‐Photon‐Sensitive and Sugar‐Targeted Nanocarriers from Degradable and Dendritic Amphiphiles
Authors: Sun Lin , Yang Yang , Dong Chang‐Ming , Wei Yen
Published: December 2010

Increasing efforts are being put into the light‐sensitive polymeric micelles that hold great potential for drug/gene/small interfering RNA delivery. However, these polymeric micelles lack highly efficient tumor‐targeting properties and near‐infrared light sensitivity, and often exhibit an uncontrollable drug‐release profile. To address these problems, a new strategy is introduced that combines sugar‐triggered targeting (active targeting) and two‐photon sensitivity to afford a degradable and dendritic micellar nanocarrier, in which the desired sugar residues and light‐responsive groups can be modularly conjugated and/or altered. A clinical anticancer drug, doxorubicin, can be released in a controlled manner by changing the light irradiation time, which is induced by the gradual disruption of micelles in aqueous solution. The glucose‐ and lactose‐coated micelles further demonstrate specific binding with the lectins Concanavalin A and Ricinus communis agglutinin, respectively, which makes them useful as targeted drug‐delivery vesicles.
Sensitivity of kinetic macro parameters to changes in dopamine synthesis, storage, and metabolism: A simulation study for [18F]FDOPA PET by a model with detailed dopamine pathway
Authors: Matsubara Keisuke , Watabe Hiroshi , Kumakura Yoshitaka , Hayashi Takuya , Endres Christopher J. , Minato Kotaro , Iida Hidehiro
Published: December 2010

Quantitative interpretation of brain [18F]FDOPA PET data has been made possible by several kinetic modeling approaches, which are based on different assumptions about complex [18F]FDOPA metabolic pathways in brain tissue. Simple kinetic macro parameters are often utilized to quantitatively evaluate metabolic and physiological processes of interest, which may include DDC activity, vesicular storage, and catabolism from 18F‐labeled dopamine to DOPAC and HVA. A macro parameter most sensitive to the changes of these processes would be potentially beneficial to identify impaired processes in a neurodegenerative disorder such as Parkinson's disease. The purpose of this study is a systematic comparison of several [18F]FDOPA macro parameters in terms of sensitivities to process‐specific changes in simulated time‐activity curve (TAC) data of [18F]FDOPA PET. We introduced a multiple‐compartment kinetic model to simulate PET TACs with physiological changes in the dopamine pathway. TACs in the alteration of dopamine synthesis, storage, and metabolism were simulated with a plasma input function obtained by a non‐human primate [18F]FDOPA PET study. Kinetic macro parameters were calculated using three conventional linear approaches (Gjedde‐Patlak, Logan, and Kumakura methods). For simulated changes in dopamine storage and metabolism, the slow clearance rate (kloss) as calculated by the Kumakura method showed the highest sensitivity to these changes. Although kloss performed well at typical ROI noise levels, there was large bias at high noise level. In contrast, for simulated changes in DDC activity it was found that Ki and VT, estimated by Gjedde‐Patlak and Logan method respectively, have better performance than kloss. Synapse 2011. © 2011 Wiley‐Liss, Inc.
Chronic corticosterone exposure alters postsynaptic protein levels of PSD‐95, NR1, and synaptopodin in the mouse brain
Authors: Cohen Julia W. , Louneva Natalia , Han Li‐Ying , Hodes Georgia E. , Wilson Robert S. , Bennett David A. , Lucki Irwin , Arnold Steven E.
Published: December 2010

Animal models provide compelling evidence that chronic stress is associated with biochemical and morphological changes in the brain, many of which are mediated by corticosterone, a principal glucocorticoid synthesized in the rodent adrenal cortex and secreted in response to stress. To better characterize the effects of chronic corticosterone at the synaptic and subsynaptic level, we implanted three‐month‐old male C57B/6 mice with 2 × 5 mg corticosterone pellets (CORT group,n= 14), 21 day release formulation (20 mg/kg/day dose) or placebo pellets (Placebo group,n= 14), 21‐day release formulation. After 20 days, brains were removed. One hemisphere was frozen for biochemical analysis by synaptosomal fractionation with Western blotting, and the other hemisphere was fixed for immunohistochemistry. Localization and expression levels for PSD‐95, NR1, and synaptopodin proteins were assessed. Biochemical analysis revealed lower protein levels of PSD‐95 (32% decrease,P< 0.001), NR1 (47%,P= 0.01), and synaptopodin (65%,P< 0.001) in the postsynaptic density subsynaptic fraction of the CORT group. Optical densitometry in immunohistochemically labeled sections also found lower levels of PSD‐95 in synaptic fields of the dentate gyrus (PSD‐95, 33% decrease,P< 0.001; NR1, 31%,P< 0.001; synaptopodin, 40%,P< 0.001) and the CA3 stratum lucidum (36%,P< 0.001, 40%,P< 0.001, and 35%,P< 0.001) of the CORT group. While mechanistic relationships for these changes are not yet known, we speculate that synaptopodin, which is involved in regulation of spine calcium kinetics and posttranslational modification and transport of locally synthesized proteins, may play an important role in the changes of PSD‐95 and NR1 protein levels and other synaptic alterations. Synapse 2011. © 2011 Wiley‐Liss, Inc.
Differential long‐term depression in CA3 but not in dentate gyrus following low‐frequency stimulation of the medial perforant path
Authors: Fung Thomas K. , Peloquin Pascal , Wu Kun , Leung L. Stan
Published: December 2010

Synaptic plasticity may depend not only on the afferent fibers but also on the recipient structure. The medial perforant path (MPP) from the entorhinalcortex projects to both the dentate gyrus (DG) and CA3, resulting in excitatory postsynaptic potentials (EPSPs) in both areas. In this study, we showed that long‐term depression (LTD) following low‐frequency stimulation of MPP was found only in CA3a, a CA3 subfield, but not in DG. Field potentials were recorded and current source density (CSD) analyzed in CA3a and DG following stimulation of MPP in urethane‐anesthetized rats. MPP evoked a short‐latency population spike (PS) and EPSP in CA3a, <2.5 ms delayed from the respective events in DG. A small electrolytic lesion of CA3a abolished the locally recorded PS in CA3a but did not affect the responses in the DG. Low‐frequency stimulation of the MPP for 600 pulses at 5 Hz, but not at 1 Hz, resulted in LTD of up to 2 h in CA3a but not in DG. High‐frequency stimulation (400 Hz bursts) of the MPP resulted in long‐term potentiation (LTP) in both CA3a and DG. LTD at CA3a was blocked by a prior intracerebroventricular administration of an N‐methyl‐D‐aspartate receptor (NMDAR) antagonist DL‐2‐amino‐5‐phosphonovaleric acid or a nonselective group I/II metabotropic glutamate receptor (mGluR) antagonist (RS)‐α‐methyl‐4‐carboxyphenylglycine. We conclude that an NMDAR and mGluR sensitive LTD is induced in CA3 but not in the DG following low‐frequency MPP stimulation in vivo, and the bi‐directional synaptic plasticity in CA3 may be responsible for its behavioral functions. Synapse, 2011. © 2011 Wiley‐Liss, Inc.
Methamphetamine treatment during development attenuates the dopaminergic deficits caused by subsequent high‐dose methamphetamine administration
Authors: Mcfadden Lisa M. , Hoonakker Amanda J. , Vieira‐Brock Paula L. , Stout Kristen A. , Sawada Nicole M. , Ellis Jonathan D. , Allen Scott C. , Walters Elliot T. , Nielsen Shannon M. , Gibb James W. , Alburges Mario E. , Wilkins Diana G. , Hanson Glen R. , Fleckenstein Annette E.
Published: December 2010

Administration of high doses of methamphetamine (METH) causes persistent dopaminergic deficits in both nonhuman preclinical models and METH‐dependent persons. Noteworthy, adolescent [i.e., postnatal day (PND) 40] rats are less susceptible to this damage than young adult (PND90) rats. In addition, biweekly treatment with METH, beginning at PND40 and continuing throughout development, prevents the persistent dopaminergic deficits caused by a “challenge” high‐dose METH regimen when administered at PND90. Mechanisms underlying this “resistance” were thus investigated. Results revealed that biweekly METH treatment throughout development attenuated both the acute and persistent deficits in VMAT2 function, as well as the acute hyperthermia, caused by a challenge METH treatment. Pharmacokinetic alterations did not appear to contribute to the protection afforded by the biweekly treatment. Maintenance of METH‐induced hyperthermia abolished the protection against both the acute and persistent VMAT2‐associated deficits suggesting that alterations in thermoregulation were caused by exposure of rats to METH duringdevelopment. These findings suggest METH during development prevents METH‐induced hyperthermia and the consequent METH‐related neurotoxicity. Synapse 2011. © 2011 Wiley‐Liss, Inc.
Using orthogonal pairs of rollers on concave beds (OPRCB) as a base isolation system—part II: application to multi‐story and tall buildings
Authors: Hosseini Mahmood , Soroor Amirhossein
Published: December 2010

Application of orthogonal pairs of rollers on concave beds (OPRCB) isolating system to short‐ and mid‐rise buildings is presented in this paper. At first, the analytical formulation of the set of equations, governing the motion of Multi Degree of Freedom (MDOF) systems, isolated by OPRCB isolators, has been developed. Then, some multi‐story regular buildings of shear type have been considered, once on fixed bases and once installed on the OPRCB isolators. Next, some horizontal and vertical accelerograms of both far‐ and near‐fault earthquakes with low‐ to high‐frequency content, particularly those with remarkable peak ground displacement values, have been selected and normalized to three peak ground acceleration levels of 0.15  g, 0.35  g and 0.7  g, and their stronger horizontal component simultaneous with their vertical component have been used for response analysis of the considered buildings. Story drifts and absolute acceleration response histories of isolated buildings have been calculated by using a program, developed in MATLAB environment by using the fourth‐order Runge–Kutta method, considering the geometrically nonlinear behavior of isolators. Maximum relative displacement and story drifts as well as absolute acceleration responses of considered isolated buildings for various earthquakes have been compared with those of corresponding fixed‐base buildings to show the high efficiency of using OPRCB isolators in multi‐story and tall regular buildings. Copyright © 2010 John Wiley & Sons, Ltd.
Electronic musical instrument shoe in consideration of universal design
Authors: Sugaya Satoshi , Kina Robin M. , Matoba Yasushi , Koumura Makoto , Vichai Saechout , Hirai Seiji
Published: December 2010

We developed a new electronic musical instrument shoe called ‘Otokutsu’. It is a shoe to play music with a foot. It can be easily played by anyone in consideration of universal design. It not only flashes but also makes sounds. It is fun and easy for everyone. Furthermore, we developed the special score for Otokutsu. It can be easily played even by beginners or the persons who do not read a score, and it enables the rehabilitation exercises for foot enjoyable. We evaluated it at some elder day‐care centers and elementary schools. We achieved to realize enjoyable and continuable rehabilitation exercises by Otokutsu. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A MAC protocol for cognitive wireless sensor body area networking
Authors: Ali Khaled A. , Sarker Jahangir H. , Mouftah Hussein T.
Published: December 2010

In this paper, a Cognitive Radio Based Medium Access Control (CR‐MAC) protocol for Wireless Sensor Body Area Networks (WSBAN) that utilizes cognitive radio transmission is proposed. In this proposal, the sensor nodes are classified into nodes of life‐critical health information and nodes of non‐critical health information. The CR‐MAC protocol prioritizes the critical packets access to the transmission medium by transmitting them with higher power while transmitting lower priority packets using lower transmission power. At the receiver, a higher priority packet experiences collision only when there are more than one critical packet transmission at the same transmission slot while non critical packets experience collision when there are more than one transmission at the same transmission slot. This protocol is evaluated analytically and through simulation. The obtained results demonstrate a differentiated service system which prioritizes critical traffic access to the transmission medium and increases the critical traffic throughput. Copyright © 2010 John Wiley & Sons, Ltd.
Utility‐based fair bandwidth sharing in vehicular networks (extended)
Authors: Pu Jian , Hamdi Mounir
Published: December 2010

The time‐constraint data traffic is very common in vehicle‐to‐infrastructure (V2I) and vehicle‐to‐vehicle (V2V) communications. Time‐constraint flows are those who have fixed start and stop times and try to maximize the transferred data volume during the limited connection time. From the view of users, the total data transmitted by each flow should be proportional to each one's holding time if the network resources are allocated fairly. However, we find that the traditional fairness concept solely based on flow rates is not suitable for this scenario. Therefore, we redefine the fairness concept regarding the application utility for time‐constraint flows. According to this new utility‐based fairness definition, we propose two practical bandwidth sharing schemes for transferring data by fast‐moving wireless nodes such as vehicles. Simulations through ns‐2 show that the proposed algorithms can achieve better utility fairness than the standard TCP and are also friendly to TCP in the long term. Copyright © 2010 John Wiley & Sons, Ltd.
RoMR:robust multicast routing in mobile wireless networks
Authors: Lynn Gretchen , Znati Taieb F.
Published: December 2010

Support for multicast services is crucial for content distribution inmobile wireless networks (MWNs). Efficient multicasting inMWNs faces challenges not encountered in other types of networks such as the mobility of nodes, the tenuous status of communication links, limited resources, and indefinite knowledge of the network topology. This paper addresses these challenges by providing a framework and architecture with proactive and reactive components to support multicasting inMWNs emphasizing reliability and efficiency of end‐to‐end packet delivery. The architecture includes theRobust Multicast Routing protocol(RoMR) to provide efficient multicast services for content distritbution MWNs. RoMR's architecture includes a proactive and reactive component. The proactive component calculates multiple multicast trees based on the prediction of future availability of the links and the assumption that the trees will become disconnected over time. The reactive components respond to changes in the network topology due to the mobility of the nodes and to changes in the multicast group's membership. The novelty of the proposed protocol stems from integrating techniques that have not previously been combined into a multicasting protocol and a unique method to calculate the relative weights of the links. In addition to the specifications of the protocol, a simulation framework was developed to test different implementations of the various components ofRoMR. Simulations compared the performance of the basic version of RoMR to a version that ignored link weights, and to the Multicast Optimized Link State Routing (MOLSR) protocol, a source tree‐based, topology‐aware multicast protocol. A statistical analysis of the results showed thatRoMRperformed better, overall, than the other two protocols. Copyright © 2010 John Wiley & Sons, Ltd.
Single‐cell monitoring using fiberoptic nanosensors
Authors: Vo‐Dinh Tuan , Zhang Yan
Published: December 2010

This article is a review on the design, fabrication, and applications of fiberoptic nanosensors for in vivo monitoring of individual living cells. The nanosensors were fabricated with tapered optical fibers with distal ends having nanometer‐sized diameters. Bioreceptors, such as antibody, peptides, and nucleic acids, are immobilized on the fiber tips and designed to be selective to target analyte molecules of interest. A laser beam is transmitted into the fiber, producing an evanescent field at the tip of the nanofiber that is used to excite target molecules bound to the bioreceptor molecules. The fluorescence originated from the analyte molecules is detected by a photo‐detection system. The advantages and limitations of nanosensors in providing minimally invasive tools to probe subcellular compartments inside individual living cells for health effect studies and medical applications are discussed in detail. WIREs Nanomed Nanobiotechnol 2011 3 79–85 DOI: 10.1002/wnan.112

This article is categorized under:

Diagnostic Tools > Biosensing

Diagnostic Tools > In Vivo Nanodiagnostics and Imaging
FEM analysis of Cosserat plates and shells based on some constitutive relations
Authors: Chróścielewski J. , Witkowski W.
Published: December 2010

We carry out further study of the constitutive laws for Cosserat plates developed by Altenbach and Eremeyev. In particular, we examine the problem of choice of the micropolar material coefficients. Requiring that the constitutive matrix is positive definite, we establish some bounds on values of micropolar constants. The constitutive relations for Cosserat plates have been implemented into formulation of shell finite elements developed within the framework of the statically and kinematically exact, nonlinear six‐parameter shell theory. By the linear parametric‐sensitivity analysis we study the influence of the micropolar material constants on the response of shell structure with orthogonal intersections of branches. Such structures can naturally be analyzed using the six‐parameter shell theory. Having established the most influential coefficients, we show how these values affect the behavior of the structure in the nonlinear range of deformations.
Experimental investigations and material modelling of curing processes under small deformations
Authors: Yagimli B. , Lion A.
Published: December 2010

There are many applications of curing epoxy resins. The paste‐like material can be applied to joint two structural parts of different materials. The curing reaction in the epoxy resin increases the stiffness of the material to fix the connected partners. Furthermore, the curing epoxy resin shrinks and the reaction generates exothermal energy. In order to characterise the exothermal reaction, experimental results of dynamic scanning calorimetry are presented. The change in the viscoelastic behaviour is measured with the rheometer AR‐G2 of TA‐Instruments. In addition, investigations of the shrinkage behaviour are presented. Based on the observed changes during the curing reaction a thermodynamic consistent material model for small deformations is introduced and the parameters of the material model are identified to reproduce the experimental data.
Dynamic stress and electric field concentration in a functionally graded piezoelectric solid with a circular hole
Authors: Dineva P. , Gross D. , Mueller R. , Rangelov T.
Published: December 2010

This work addresses the evaluation of the stress and electric field concentrations around a circular hole in a functionally graded piezoelectric plane subjected to anti‐plane elastic SH‐wave and in‐plane time‐harmonic electric load. All material parameters vary exponentially along a line of arbitrary orientation in the plane of the piezoelectric material under consideration. The computational tool is a non‐hypersingular traction based boundary integral equation method (BIEM). The kernel functions used in the BIEM are exact fundamental solutions that have been derived in previous work by the authors. Numerical solutions for the stress and electric field concentration factors (SCF and EFCF, respectively) around the perimeter of the hole are obtained. The simulation demonstrates the efficiency of the computational approach and its potential to reveal in an adequate way the dynamic stress and electric field distribution around the hole. Presented are results showing their dependence on various system parameters as e.g. the electro‐mechanical coupling, the type of the dynamic load and its characteristics, the wave‐hole and wave‐material interaction and the magnitude and direction of the material inhomogeneity.
Angiointervention: High Rates of Failure Following Blunt Renal Injuries
Authors: Menaker Jay , Joseph Bellal , Stein Deborah M. , Scalea Thomas M.
Published: December 2010

Background

Nonoperative management (NOM) of solid organ injury after blunt trauma is now standard. Recently, angioembolization (AE) has been used to extend NOM. Few data exist on evaluating NOM of blunt renal injuries (BRIs). We sought to determine the overall efficacy of NOM as well as the outcome of AE in patients with BRI.

Methods

The trauma registry was used to identify all patients with BRI between January 2002 and December 2008. Medical records were reviewed for demographics, grade of injury, use of angiographic intervention, and outcome.

Results

A total of 434 patients with BRI were identified, 416 of whom had planned NOM; 337 (81%) patients were successfully managed without further intervention for their BRI. In all, 79 (19%) patients underwent angiography; 22 (27.8%) of these patients underwent AE, and 6 (27.2%) failed 1.2 ± 0.8 days after AE. Patients who failed AE had a significantly higher blood transfusion requirement during the first 24 h of admission (p = 0.01). Seven patients not embolized failed 1.9 ± 1.9 days after angiography. Thus, of the 79 patients having angiography, 13 (16.5%) failed and required laparotomy to treat their BRIs. Overall failure rate of NOM was 3.1% (13/416). Patients who failed angiography, with or without AE, required more blood during the first 24 h after admission (p = 0.03).

Conclusions

NOM of BRI is safe and effective, with an overall failure rate of 3.1%. However, angiography with or without AE has substantial failure rates. Patients with higher‐grade injuries and active vascular extravasation on admission computed tomography scan also fail NOM regardless of therapy. The blood transfusion requirement during the first 24 h may indicate who will require operative intervention following angiography. Close observation and/or early laparotomy are wise for these high‐risk patients.