bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid‐State Reference Electrode Based on Electrodeposited Nanoporous Platinum for Microchip
Authors: Han Ji‐Hyung , Park Sejin , Boo Hankil , Kim Hee Chan , Nho Jongmin , Chung Taek Dong 
Published: February 2007

AbstractA new solid‐state reference electrode operating in buffered aqueous solution for electrochemical system on microfluidic chip is reported. The anodized nanoporous platinum showed its usefulness as a solid‐state reference electrode owing to near‐Nernstian behavior, low hysteresis, and quick response. The presence of redox couples such as Fe(CN)$\rm{ _6^{3 - /4 - } }$, bringing about significant interference, can be successfully suppressed by an electropolymerized poly‐1,3‐phenylendiamine (poly‐m‐PD) layer on the nanoporous platinum surface. Since the poly‐m‐PD coated nanoporous platinum oxide responds exclusively to pH, its potential should be constant and stable in a buffer solution. The nanoporous platinum oxide with poly‐m‐PD film is easy to produce and is particularly compatible with microfabrication. The experimental results in this study demonstrate that the proposed system successfully works as a solid‐state reference electrode that should be integrated on microchips for microanalysis systems.
Improvement of Selectivity and Stability of Amperometric Detection of Hydrogen Peroxide Using Prussian Blue‐PAMAM Supramolecular Complex Membrane as a Catalytic Layer
Authors: Wu Shouguo , Wang Taoling , Wang Changqin , Gao Zongyong , Wang Chuanqin 
Published: February 2007

AbstractA novel hydrogen peroxide (H2O2) sensor was fabricated by using a submonolayer of 3‐mercaptopropionic acid (3‐MPA) adsorbed on a polycrystalline gold electrode further reacted with poly(amidoamine) (PAMAM) dendrimer (generation 4.0) to obtain a film on which Prussian Blue (PB) was later coordinated to afford a mixed and stable electrocatalytic layer for H2O2 reduction. On the basis of the electrochemical behaviors, atomic force microscopy (AFM) and X‐ray photoelectron spectra (XPS), it is suggested that the PB molecules are located within the dendritic structure of the surface attached PAMAM dendrimers. It was found that the PB/PAMAM/3‐MPA/Au modified electrode showed an excellent electrocatalytic activity for H2O2 reduction. The effects of applied potential and pH of solution upon the response of the modified electrode were investigated for an optimum analytical performance. Even in the presence of dissolved oxygen, the sensor exhibited highly sensitive and rapid response to H2O2. The steady‐state cathodic current responses of the modified electrode obtained at −0.20 V (vs. SCE) in air‐saturated 0.1 mol L−1 phosphate buffer solution (PBS, pH 6.50) showed a linear relationship to H2O2 concentration ranging from 1.2×10−6 mol L−1 to 6.5×10−4 mol L−1 with a detection limit of 3.1×10−7 mol L−1. Performance of the electrode was evaluated with respected to possible interferences such as ascorbic acid and uric acid etc. The selectivity, stability, and reproducibility of the modified electrode were satisfactory.
Irreversible and Reversible Deactivation of Bilirubin Oxidase by Urate
Authors: Shin Hyosul , Kang Chan , Heller Adam 
Published: February 2007

AbstractOxygen is electroreduced to water on a carbon cathode coated with wired bilirubin oxidase in a pH 7.4 0.15 M NaCl phosphate buffer solution at 37 °C at much lesser polarization than it is on a pure platinum cathode in 0.5 M H2SO4. While the wired bilirubin oxidase cathode operates for over a week in the aerated or oxygenated buffer solution, it is degraded rapidly when in serum. We reported earlier that in the presence of O2 an intermediate product of the electrooxidation of urate, which is a normal serum component, irreversibly damages the wired bilirubin oxidase and also reported that the electrocatalyst is irreversibly damaged, in the absence of urate, when it is brought, by disconnecting the electrode, to the O2/H2O half cell potential at pH 7.4. Here we report that a) dissolved bilirubin oxidase is irreversibly and rapidly damaged by urate in the presence of O2; and b) that the immobilized wired bilirubin oxidase electrocatalyst is not only irreversibly deactivated by urate in the presence of O2 in a few hours, but is initially reversibly deactivated, in 1 min or less, by the urate in the presence of O2.
Xanthine Sensors Based on Anodic and Cathodic Detection of Enzymatically Generated Hydrogen Peroxide
Authors: Rahman Md. Aminur , Won Mi‐Sook , Shim Yoon‐Bo 
Published: February 2007

AbstractA xanthine biosensor was fabricated by the covalent immobilization of xanthine oxidase (XO) onto a functionalized conducting polymer (Poly‐5, 2′: 5′, 2″‐terthiophine‐3‐carboxylic acid), poly‐TTCA through the formation of amide bond between carboxylic acid groups of poly‐TTCA and amine groups of enzyme. The immobilization of XO onto the conducting polymer (XO/poly‐TTCA) was characterized using cyclic voltammetry, quartz crystal microbalance (QCM), and X‐ray photoelectron spectroscopy (XPS) techniques. The direct electron transfer of the immobilized XO at poly‐TTCA was found to be quasireversible and the electron transfer rate constant was determined to be 0.73 s−1. The biosensor efficiently detected xanthine through oxidation at +0.35 V and reduction at −0.25 V (versus Ag/AgCl) of enzymatically generated hydrogen peroxide. Various experimental parameters, such as pH, temperature, and applied potential were optimized. The linear dynamic ranges of anodic and cathodic detections of xanthine were between 5.0×10−6−1.0×10−4 M and 5.0×10−7 to 1.0×10−4 M, respectively. The detection limits were determined to be of 1.0×10−6 M and 9.0×10−8 M with anodic and cathodic processes, respectively. The applicability of the biosensor was tested by detecting xanthine in blood serum and urine real samples.
Sensitive Biosensors Based on (Dendrimer Encapsulated Pt Nanoparticles)/Enzyme Multilayers
Authors: Zhu Yihua , Zhu Huiyu , Yang Xiaoling , Xu Lihuan , Li Chunzhong 
Published: February 2007

AbstractA sensitive enzymed‐based biosensor for glucose has been obtained by introducing dendrimer encapsulated Pt nanoparticles via a layer‐by‐layer assembling method. The free amine groups located on each poly(amidoamine) dendrimer molecule were exploited to covalently attach enzyme to the dendrimer chains using carbodiimide coupling. The resultant enzyme electrodes are shown to have excellent sensitivity (as high as 30.33 μA mM−1 cm−2) and a limit of detection (about 0.1 μmol L−1), depending on metal nanoparticles within dendrimers and the biocompatibility of dendrimers, the linear response range to glucose (from 5 μM to 1.0 mM), a fast response time (within 5 s), and good reproducibility (<8% relative standard deviation between electrodes at low substrate concentration). The sensitivities, and stabilities determined experimentally have demonstrated the potential of dendrimer encapsulated Pt nanoparticles as a novel candidate for enzymatic glucose biosensors.
Unified models for adaptive OFDM systems when QAM or PSK modulation is applied
Authors: Assimakopoulos Costas , Pavlidou F.‐N. 
Published: February 2007

AbstractIn this paper, the solutions of the major bit‐loading problems that are found in the literature, are unified into simple equations (models). These equations give an insight of the affection of the channel over a multicarrier system. Moreover, the models allow the transition from the solution of one loading problem to the solution of the others. The models are dependent on the modulation type that is used. We examine the quadrature amplitude modulation (QAM) modulated orthogonal frequency division multiplexing (OFDM), and the phase shift keying (PSK)‐modulated OFDM systems. For each modulation type, the continuous throughput model is extracted. The continuous throughput model refers to a system that its subcarriers can be loaded with non‐integer number of bits. The non‐integer bit distribution can then be rounded to integers, using a rounding method. The models except from the calculation of the optimised quantities (total data rate, total power and symbol error rate) without the need of running a loading algorithm to its extent, provide a means to manipulate a whole multicarrier system in a way similar to single‐carrier system. Copyright © 2007 John Wiley & Sons, Ltd.
Performance enhancement of perfect difference codes with spectral amplitude coding using sub‐optimal decision threshold
Authors: Jhou Jhih‐Syue , Lin Jen‐Yung , Wen Jyh‐Horng 
Published: February 2007

AbstractThis paper applies perfect difference code (PDC) to develop an optical code‐division multiple‐access (OCDMA) system with spectral amplitude coding (SAC). The differential receiver of the proposed systems exploits the cross‐correlation property of PDC to remove the multiple‐access interference (MAI) without reducing the power of the received signal. The threshold applied in the data decision process has a crucial influence on the bit error rate (BER). Hence, this study investigates the effects of several different decision rules. The numerical results show that the BERs of the synchronous OCDMA system using PDC proposed by Weng and Wu are 100 times and 17 times greater than those of the current system for code sizes of 183 and 307, respectively, under conditions of equal power budgets. To achieve the same BERs, the theoretical analysis reveals that the transmission power required by the Weng's system is around k/(k‐1) times greater than that of the current system, where k denotes the code weight of the signature code employed. Additionally, under conditions of reliable communication (i.e. BER ≤ 10−9), the capacity of the proposed system is almost one and half times greater than that of Weng's system. Regarding the data decision threshold, this study proposes a realisable sub‐optimal decision threshold as a replacement for the optimal decision threshold. The performance of the proposed system using this sub‐optimal threshold is found to be only marginally poorer than that obtained when the optimal decision threshold is employed. Therefore, the proposed sub‐optimal threshold provides a suitable means of improving the system performance of SAC OCDMA systems using signature codes with a fixed in‐phase cross‐correlation property. Copyright © 2007 John Wiley & Sons, Ltd.
The use of monthly indicators to forecast quarterly GDP in the short run: an application to the G7 countries
Authors: Golinelli Roberto , Parigi Giuseppe 
Published: February 2007

AbstractThe delayed release of the National Account data for GDP is an impediment to the early understanding of the economic situation. In the short run, this information gap may be at least partially eliminated by bridge models (BM) which exploit the information content of timely updated monthly indicators. In this paper we examine the forecasting ability of BM for GDP growth in the G7 countries and compare their performance to that of univariate and multivariate statistical benchmark models. We run four alternative one‐quarter‐ahead forecasting experiments to assess BM performance in situations as close as possible to the actual forecasting activity. BM are estimated for GDP both for single countries (USA, Japan, Germany, France, UK, Italy and Canada), and area‐wide (G7, European Union, and Euro area). BM forecasting ability is always superior to that of benchmark models, provided that at least some monthly indicator data are available over the forecasting horizon.  Copyright © 2007 John Wiley & Sons, Ltd.
Using a heterogeneous multinomial probit model with a neural net extension to model brand choice
Authors: Hruschka Harald 
Published: February 2007

AbstractThe multinomial probit model introduced here combines heterogeneity across households with flexibility of the (deterministic) utility function. To achieve flexibility deterministic utility is approximated by a neural net of the multilayer perceptron type. A Markov Chain Monte Carlo method serves to estimate heterogeneous multinomial probit models which fulfill economic restrictions on signs of (marginal) effects of predictors (e.g., negative for price). For empirical choice data the heterogeneous multinomial probit model extended by a multilayer perceptron clearly outperforms all the other models studied. Moreover, replacing homogeneous by heterogeneous reference price mechanisms and thus allowing price expectations to be formed differently across households also leads to better model performance. Mean utility differences and mean elasticities w.r.t. price and price deviation from reference price demonstrate that models with linear utility and nonlinear utility approximated by a multilayer perceptron lead to very different implications for managerial decision making.  Copyright © 2007 John Wiley & Sons, Ltd.
Reactivation with a simple exposure to the experimental environment is sufficient to induce reconsolidation requiring protein synthesis in the hippocampal CA3 region in mice
Authors: Artinian Julien , Jaeger Xavier De , Fellini Laetitia , Saint Blanquat Paul de , Roullet Pascal 
Published: February 2007

AbstractOur understanding of the memory reconsolidation process is at an earlier stage than that of consolidation. For example, it is unclear if, as for memory consolidation, reconsolidation of a memory trace necessitates protein synthesis. In fact, conflicting results appear in the literature and this discrepancy may be due to differences in the experimental reactivation procedure. Here, we addressed the question of whether protein synthesis in the CA3 hippocampal region is crucial in memory consolidation and reconsolidation of allocentric knowledge after reactivation in different experimental conditions in the Morris water maze. We showed (1) that an injection of the protein synthesis inhibitor anisomycin in the CA3 region during consolidation or after a single reactivation trial disrupted performance and (2) that protein synthesis is required even after a simple contextual reactivation without any learning trial and independently of the presence of the reinforcement. This work demonstrates that a simple exposure to the spatial environment is sufficient to reactivate the memory trace, to make it labile, and that reconsolidation of this trace requires de novo protein synthesis. © 2007 Wiley‐Liss, Inc.
Reactivation of behavioral activity during sharp waves: A computational model for two stage hippocampal dynamics
Authors: Molter Colin , Sato Naoyuki , Yamaguchi Yoko 
Published: February 2007

AbstractThe rodent hippocampus is known to exhibit two very distinctive patterns of activity: theta with place selective cells firing during exploratory behavior and sharp waves (SPWs) associated with collective discharges in the CA3 during slow wave sleep (SWS), inactivity while awake and consummatory behavior. A great deal of evidence has demonstrated that the cells activated during SPWs events are representative of previous behavioral activity, which suggests an important functional role of off‐line learning and consolidation for these SPWs events. Supporting this view, forward, and more recently, reverse replay of linear track behavioral sequences have been reported in rodent's hippocampal place cells during SPWs. We demonstrate here that these patterns of reactivation can be successfully reproduced by relying on a computational model of the hippocampus with theta phase precession and synaptic plasticity during theta rhythm. Two mechanisms are proposed to initiate SPWs events: random reactivation in the presence of rapid, irregular subthreshold inputs and place selective cell activations. In 2D navigation computational experiments, rather than observing the perfect replay of experienced pathways, new pathways “experienced during immobility” emerge. This suggests a neural mechanism for shortcut navigation. © 2007 Wiley‐Liss, Inc.
Mucin‐depleted foci are modulated by dietary treatments and show deregulation of proliferative activity in carcinogen‐treated rodents
Authors: Femia Angelo Pietro , Caderni Giovanna , Bottini Consuelo , Salvadori Maddalena , Dolara Piero , Tessitore Luciana 
Published: February 2007

AbstractThe correlation between mucin‐depleted foci (MDF) and colon carcinogenesis was studied in F344 rats initiated with 1,2‐dimethylhydrazine and treated with a chemopreventive regimen (polyethylene glycol, PEG) or with a promoting diet (high‐corn oil). High corn oil diet increased MDF, while PEG reduced them. The expression of p27 and p16, inhibitors of cyclin‐dependent kinases, which inhibit the progression of the cell cycle, was studied by immunohistochemistry in MDF and in aberrant crypt foci (ACF) of control rats. In both MDF and ACF, the nuclear expression of p27 was markedly reduced, while p16 was reduced to a lower extent. Mitotic activity was higher in MDF and ACF than in normal mucosa of control rats. MDF were also identified in azoxymethane‐initiated SWR/J mice. These results further confirm that MDF are preneoplastic lesions and could be useful biomarkers of colon carcinogenesis. © 2007 Wiley‐Liss, Inc.
Expression of neutral endopeptidase (NEP/CD10) on pancreatic tumor cell lines, pancreatitis and pancreatic tumor tissues
Authors: Erhuma Mabruk , Köbel Martin , Mustafa Tarek , Wulfänger Jens , Dralle Henning , Hoang‐Vu Cuong , Langner Jürgen , Seliger Barbara , Kehlen Astrid 
Published: February 2007

AbstractNeutral endopeptidase (NEP/CD10) is a cell surface zinc metalloprotease cleaving peptide bounds on the amino terminus of hydrophobic amino acids and inactivating multiple physiologically active peptides. Loss or decrease in NEP/CD10 expression have been reported in many types of malignancies, but the role of NEP/CD10 in pancreatic carcinoma has not yet been identified. Using real‐time RT‐PCR, flow cytometry as well as immunohistochemistry, NEP/CD10 expression was quantified in both pancreatic carcinoma cell lines and in tumor specimens obtained from patients with primary pancreatic carcinomas. Three out of 8 pancreatic carcinoma cell lines exhibit heterogeneous NEP/CD10 expression levels: PATU‐8988T expressed the highest NEP/CD10 levels, whereas HUP‐T4 and HUP‐T3 cells showed a moderate to low NEP/CD10 expression. NEP/CD10 immunoreactivity was found in 6 of 24 pancreatic ductal adenocarcinomas, but also in 3 of 6 tissues of patients with chronic pancreatitis. NEP/CD10 expression in pancreatic tumor lesions and cell lines was not associated with tumor grading and staging. Treatment of PATU‐8988T cells with the histone deacetylase inhibitors sodium butyrate and valproic acid induced an increase of NEP/CD10 expression. This was accompanied by a reduced cell proliferation rate of PATU‐8988T cells, which was increased by the addition of the enzyme activity inhibitors phosphoramidon and thiorphan. Thus, NEP/CD10 is differentially expressed in pancreatic tumors and might be involved in the proliferative activity of pancreatic cancer cells. However, further studies are needed to provide more detailed information of the role of NEP/CD10 under physiological and pathophysiological conditions of the pancreas. © 2007 Wiley‐Liss, Inc.
Increased expression of estrogen‐related receptor α (ERRα) is a negative prognostic predictor in human prostate cancer
Authors: Fujimura Tetsuya , Takahashi Satoru , Urano Tomohiko , Kumagai Jinpei , Ogushi Tetsuo , Horie‐Inoue Kuniko , Ouchi Yasuyoshi , Kitamura Tadaichi , Muramatsu Masami , Inoue Satoshi 
Published: February 2007

AbstractThe nuclear receptor ERRα (estrogen‐related receptor α) is known to modulate the estrogen‐signaling pathway, but the biological significance of ERRα in the prostate remains unclear. We investigated the expression of ERRα in human prostate tissues and cancer cell lines to evaluate the potential roles of the receptor in prostate cancer (PC). Western blot analysis of ERRα was performed in three cell lines of human PC (LNCaP, DU145 and PC‐3). The expressions of ERRα in cancerous lesions (n = 106) and benign foci (n = 99) of 106 surgically obtained prostate specimens were evaluated by immunohistochemistry. The relationships between the ERRα expression and clinicopathological features were evaluated. Western blot analysis using the polyclonal anti‐ERRα antibody detected a 52 kD band in all three PC cell lines. Positive immunostaining of ERRα in the nuclei was found in 73 (69%) cancerous and 47 (47.5%) benign epithelium, whereas the stromal tissues were negative for ERRα. The mean immunoreactivity score (IR score) of the cancerous lesions (3.5 ± 2.6) was significantly higher than that of the benign foci (1.8 ± 2.1) (p < 0.0001). The IR score of the cancerous lesions significantly correlated with the Gleason score (p = 0.0135). Univariate and multivariate hazard analyses revealed significant correlations between elevated ERRα expression and poor cancer‐specific survival (p = 0.0141 and 0.0367, respectively). The enhanced expression of ERRα might play a role in the development of human PC and serve as a significant prognostic factor for the disease. © 2006 Wiley‐Liss, Inc.
Increased expression of Dyrk1a in HPV16 immortalized Keratinocytes enable evasion of apoptosis
Authors: Chang Hung‐Shu , Lin Ching‐Hui , Yang Chien‐Hui , Yen Ming‐Shyen , Lai Chiung‐Ru , Chen Yi‐Rong , Liang Yuh‐Jin , Yu Winston C.Y. 
Published: February 2007

AbstractImmortalization is a critical event in virus‐related oncogenesis. No enough information, however, is currently available to elucidate the changes that occur in cellular molecules during immortalization. To identify potential cellular markers or regulators involving in immortalization, a paired‐cell model of primary foreskin keratinocytes (FK) and HPV16 immortalized foreskin keratinocytes were established. Using mRNA differential display, RT‐PCR and Northern blot methods, we have identified and confirmed that Dyrk1a (dual‐specificity tyrosine‐phosphorylated and regulated kinase 1A) is present and increased in HPV16 immortalized cells, but is absent in primary keratinocytes. Moreover, transfection of E7 siRNA oligo into immortalized cells leads to a diminishing E7 expression and the eventual disappearance of Dyrk1a. Similar results of Dyrk1a expressional differences could also be seen when tissue specimens were compared using LCM/real‐time PCR and immunohistochemistry analysis; malignant cervical lesions contain significantly more DYRK1A than normal tissue. It was also demonstrated that raised DYRK1A could rearrange the cellular localization of FKHR (forkhead in rhabdomyosarcoma), an apoptosis activator, and suppress BAD. Importantly, this phenomenon can be reversed when endogenous Dyrk1a was knocked down in immortalized cells by RNA interference. These results suggest that the raised Dyrk1a in HPV16 immortalized keratinocytes and cervical lesions may serve as a candidate antiapoptotic factor in the FKHR regulated pathway and initiate immortalization and tumorigenesis gradually. © 2007 Wiley‐Liss, Inc.