bluuebunny/crossref_metadata_2025 huggingface dataset:
Visible Light-Photocatalytic Activity of Sulfate-Doped Titanium Dioxide Prepared by the Sol−Gel Method
Authors: Nishikiori Hiromasa , Hayashibe Maki , Fujii Tsuneo
Published: April 2013

Sulfate-doped TiO2 was prepared from sol−gel systems containing titaniumalkoxide and sulfuric acid. The time needed for gelation of the systems was significantlyreduced by ultrasonic irradiation. The doped sulfate was observed by FTIR and XPSmeasurements. Some sulfate ions remained in the TiO2 even after heating at 300−600 °C.The UV and visible photocatalytic activities of the samples were confirmed by thedegradation of trichloroethylene (TCE). The activity of the photocatalyst samples duringthe UV irradiation strongly depended on their crystallinities rather than their specificsurface areas, i.e., adsorption ability. The degradation rate during the visible irradiationdepended on both the adsorption ability and visible absorption of the photocatalystsamples. The visible absorption induced by the sulfate-doping was effective for theTCE degradation.
Pushing for the Extreme: Estimation of Poisson Distribution from Low Count Unreplicated Data—How Close Can We Get?
Authors: Tiňo Peter
Published: April 2013

Studies of learning algorithms typically concentrate on situations where potentially ever growing training sample is available. Yet, there can be situations (e.g., detection of differentially expressed genes on unreplicated data or estimation of time delay in non-stationary gravitationally lensed photon streams) where only extremely small samples can be used in order to perform an inference. On unreplicated data, the inference has to be performed on the smallest sample possible—sample of size 1. We study whether anything useful can be learnt in such extreme situations by concentrating on a Bayesian approach that can account for possible prior information on expected counts. We perform a detailed information theoretic study of such Bayesian estimation and quantify the effect of Bayesian averaging on its first two moments. Finally, to analyze potential benefits of the Bayesian approach, we also consider Maximum Likelihood (ML) estimation as a baseline approach. We show both theoretically and empirically that the Bayesian model averaging can be potentially beneficial.
Fuzzy Logic and Education: Teaching the Basics of Fuzzy Logic through an Example (by Way of Cycling)
Authors: Sobrino Alejandro
Published: April 2013

Fuzzy logic dates back to 1965 and it is related not only to current areas of knowledge, such as Control Theory and Computer Science, but also to traditional ones, such as Philosophy and Linguistics. Like any logic, fuzzy logic is concerned with argumentation, but unlike other modalities, which focus on the crisp reasoning of Mathematics, it deals with common sense reasoning; i.e., with approximate reasoning. Although the teaching of logic has formed part of mainstream education for many years, fuzzy logic is a much more recent inclusion. In this paper we emphasize the desirability of having illustrative examples related to students’ everyday activities, such as sports, in order to introduce fuzzy logic in higher education. Taking an example from cycling, we show, step by step, how to model an approximate reasoning regarding the choice of a ratio (a combination of freewheel and chainring) in order to advance more or less with each rotation of the pedals. Led by this example, a number of alternatives attending to the formal representation of the premises and the ways of inferring a plausible conclusion are analyzed. The choices made between alternatives are justified. We show that the conclusion inferred in the example is consistent with the models selected for premises and fuzzy inference and similar to that concluded by a human being.
How Pleasant Sounds Promote and Annoying Sounds Impede Health: A Cognitive Approach
Authors: Andringa Tjeerd , Lanser J.
Published: April 2013

This theoretical paper addresses the cognitive functions via which quiet and in general pleasurable sounds promote and annoying sounds impede health. The article comprises a literature analysis and an interpretation of how the bidirectional influence of appraising the environment and the feelings of the perceiver can be understood in terms of core affect and motivation. This conceptual basis allows the formulation of a detailed cognitive model describing how sonic content, related to indicators of safety and danger, either allows full freedom over mind-states or forces the activation of a vigilance function with associated arousal. The model leads to a number of detailed predictions that can be used to provide existing soundscape approaches with a solid cognitive science foundation that may lead to novel approaches to soundscape design. These will take into account that louder sounds typically contribute to distal situational awareness while subtle environmental sounds provide proximal situational awareness. The role of safety indicators, mediated by proximal situational awareness and subtle sounds, should become more important in future soundscape research.
Epigenetic Silencing of DKK3 in Medulloblastoma
Authors: Valdora Francesca , Banelli Barbara , Stigliani Sara , Pfister Stefan , Moretti Stefano , Kool Marcel , Remke Marc , Bai Alfa , Brigati Claudio , Hielscher Thomas , Romani Massimo , Servidei Tiziana , Zollo Massimo , Cinalli Giuseppe , Oberthuer André , Tonini Gian , Coco Simona
Published: April 2013

Medulloblastoma (MB) is a malignant pediatric brain tumor arising in the cerebellum consisting of four distinct subgroups: WNT, SHH, Group 3 and Group 4, which exhibit different molecular phenotypes. We studied the expression of Dickkopf (DKK) 1–4 family genes, inhibitors of the Wnt signaling cascade, in MB by screening 355 expression profiles derived from four independent datasets. Upregulation of DKK1, DKK2 and DKK4 mRNA was observed in the WNT subgroup, whereas DKK3 was downregulated in 80% MBs across subgroups with respect to the normal cerebellum (p < 0.001). Since copy number aberrations targeting the DKK3 locus (11p15.3) are rare events, we hypothesized that epigenetic factors could play a role in DKK3 regulation. Accordingly, we studied 77 miRNAs predicting to repress DKK3; however, no significant inverse correlation between miRNA/mRNA expression was observed. Moreover, the low methylation levels in the DKK3 promoters (median: 3%, 5% and 5% for promoter 1, 2 and 3, respectively) excluded the downregulation of gene expression by methylation. On the other hand, the treatment of MB cells with Trichostatin A (TSA), a potent inhibitor of histone deacetylases (HDAC), was able to restore both DKK3 mRNA and protein. In conclusion, DKK3 downregulation across all MB subgroups may be due to epigenetic mechanisms, in particular, through chromatin condensation.
Protein Tyrosine Nitration and Thiol Oxidation by Peroxynitrite—Strategies to Prevent These Oxidative Modifications
Authors: Daiber Andreas , Daub Steffen , Bachschmid Markus , Schildknecht Stefan , Oelze Matthias , Steven Sebastian , Schmidt Patrick , Megner Alexandra , Wada Masayuki , Tanabe Tadashi , Münzel Thomas , Bottari Serge , Ullrich Volker
Published: April 2013

The reaction product of nitric oxide and superoxide, peroxynitrite, is a potent biological oxidant. The most important oxidative protein modifications described for peroxynitrite are cysteine-thiol oxidation and tyrosine nitration. We have previously demonstrated that intrinsic heme-thiolate (P450)-dependent enzymatic catalysis increases the nitration of tyrosine 430 in prostacyclin synthase and results in loss of activity which contributes to endothelial dysfunction. We here report the sensitive peroxynitrite-dependent nitration of an over-expressed and partially purified human prostacyclin synthase (3.3 μM) with an EC50 value of 5 μM. Microsomal thiols in these preparations effectively compete for peroxynitrite and block the nitration of other proteins up to 50 μM peroxynitrite. Purified, recombinant PGIS showed a half-maximal nitration by 10 μM 3-morpholino sydnonimine (Sin-1) which increased in the presence of bicarbonate, and was only marginally induced by freely diffusing NO2-radicals generated by a peroxidase/nitrite/hydrogen peroxide system. Based on these observations, we would like to emphasize that prostacyclin synthase is among the most efficiently and sensitively nitrated proteins investigated by us so far. In the second part of the study, we identified two classes of peroxynitrite scavengers, blocking either peroxynitrite anion-mediated thiol oxidations or phenol/tyrosine nitrations by free radical mechanisms. Dithiopurines and dithiopyrimidines were highly effective in inhibiting both reaction types which could make this class of compounds interesting therapeutic tools. In the present work, we highlighted the impact of experimental conditions on the outcome of peroxynitrite-mediated nitrations. The limitations identified in this work need to be considered in the assessment of experimental data involving peroxynitrite.
Tailoring the Models of Transcription
Authors: Pance Alena
Published: April 2013

Molecular biology is a rapidly evolving field that has led to the development of increasingly sophisticated technologies to improve our capacity to study cellular processes in much finer detail. Transcription is the first step in protein expression and the major point of regulation of the components that determine the characteristics, fate and functions of cells. The study of transcriptional regulation has been greatly facilitated by the development of reporter genes and transcription factor expression vectors, which have become versatile tools for manipulating promoters, as well as transcription factors in order to examine their function. The understanding of promoter complexity and transcription factor structure offers an insight into the mechanisms of transcriptional control and their impact on cell behaviour. This review focuses on some of the many applications of molecular cut-and-paste tools for the manipulation of promoters and transcription factors leading to the understanding of crucial aspects of transcriptional regulation.
Combinatorial Techniques to Efficiently Investigate and Optimize Organic Thin Film Processing and Properties
Authors: Wieberger Florian , Kolb Tristan , Neuber Christian , Ober Christopher , Schmidt Hans-Werner
Published: April 2013

In this article we present several developed and improved combinatorial techniques to optimize processing conditions and material properties of organic thin films. The combinatorial approach allows investigations of multi-variable dependencies and is the perfect tool to investigate organic thin films regarding their high performance purposes. In this context we develop and establish the reliable preparation of gradients of material composition, temperature, exposure, and immersion time. Furthermore we demonstrate the smart application of combinations of composition and processing gradients to create combinatorial libraries. First a binary combinatorial library is created by applying two gradients perpendicular to each other. A third gradient is carried out in very small areas and arranged matrix-like over the entire binary combinatorial library resulting in a ternary combinatorial library. Ternary combinatorial libraries allow identifying precise trends for the optimization of multi-variable dependent processes which is demonstrated on the lithographic patterning process. Here we verify conclusively the strong interaction and thus the interdependency of variables in the preparation and properties of complex organic thin film systems. The established gradient preparation techniques are not limited to lithographic patterning. It is possible to utilize and transfer the reported combinatorial techniques to other multi-variable dependent processes and to investigate and optimize thin film layers and devices for optical, electro-optical, and electronic applications.
Design, Synthesis and Antitumor Activity of Novel 4-Methyl-(3'S,4'S)-cis-khellactone Derivatives
Authors: Ren Luhui , Du Xue , Hu Mengnan , Yan Chaoqun , Liang Taigang , Li Qingshan
Published: April 2013

An asymmetric synthesis of a series of novel 4-methyl-(3'S,4'S)-cis-khellactone derivatives 3a–o is reported for the first time. Their structures were confirmed by 1H-NMR, 13C-NMR and MS. Their cytotoxic activity was evaluated by the MTT assay against three selected human cancer cell lines: HEPG-2 (human liver carcinoma), SGC-7901 (human gastric carcinoma), LS174T (human colon carcinoma). Some compounds showed high inhibitory activity against these human cancer cell lines. Among them, compound 3a exhibited strong cytotoxicity, with IC50 values ranging from 8.51 to 29.65 μM. The results showed that 4-methyl-cis-khellactone derivatives with S,S configuration could be a potential antitumor agents.
The Three Catecholics Benserazide, Catechol and Pyrogallol are GPR35 Agonists
Authors: Deng Huayun , Fang Ye
Published: April 2013

Nearly 1% of all clinically used drugs are catecholics, a family of catechol-containing compounds. Using label-free dynamic mass redistribution and Tango β-arrestin translocation assays, we show that several catecholics, including benserazide, catechol, 3-methoxycatechol, pyrogallol, (+)-taxifolin and fenoldopam, display agonistic activity against GPR35.
Combinations of Mutations Sufficient to Alter Arabidopsis Leaf Dissection
Authors: Blein Thomas , Pautot Véronique , Laufs Patrick
Published: April 2013

Leaves show a wide range of shapes that results from the combinatory variations of two main parameters: the relative duration of the morphogenetic phase and the pattern of dissection of the leaf margin. To further understand the mechanisms controlling leaf shape, we have studied the interactions between several loci leading to increased dissection of the Arabidopsis leaf margins. Thus, we have used (i) mutants in which miR164 regulation of the CUC2 gene is impaired, (ii) plants overexpressing miR319/miRJAW that down-regulates multiple TCP genes and (iii) plants overexpressing the STIMPY/WOX9 gene. Through the analysis of their effects on leaf shape and KNOX I gene expression, we show that these loci act in different pathways. We show, in particular, that they have synergetic effects and that plants combining two or three of these loci show dramatic modifications of their leaf shapes. Finally, we present a working model for the role of these loci during leaf development.
Using Low Resolution Satellite Imagery for Yield Prediction and Yield Anomaly Detection
Authors: Rembold Felix , Atzberger Clement , Savin Igor , Rojas Oscar
Published: April 2013

Low resolution satellite imagery has been extensively used for crop monitoring and yield forecasting for over 30 years and plays an important role in a growing number of operational systems. The combination of their high temporal frequency with their extended geographical coverage generally associated with low costs per area unit makes these images a convenient choice at both national and regional scales. Several qualitative and quantitative approaches can be clearly distinguished, going from the use of low resolution satellite imagery as the main predictor of final crop yield to complex crop growth models where remote sensing-derived indicators play different roles, depending on the nature of the model and on the availability of data measured on the ground. Vegetation performance anomaly detection with low resolution images continues to be a fundamental component of early warning and drought monitoring systems at the regional scale. For applications at more detailed scales, the limitations created by the mixed nature of low resolution pixels are being progressively reduced by the higher resolution offered by new sensors, while the continuity of existing systems remains crucial for ensuring the availability of long time series as needed by the majority of the yield prediction methods used today.
Hidden Markov Models for Real-Time Estimation of Corn Progress Stages Using MODIS and Meteorological Data
Authors: Shen Yonglin , Wu Lixin , Di Liping , Yu Genong , Tang Hong , Yu Guoxian , Shao Yuanzheng
Published: April 2013

Real-time estimation of crop progress stages is critical to the US agricultural economy and decision making. In this paper, a Hidden Markov Model (HMM) based method combining multisource features has been presented. The multisource features include mean Normalized Difference Vegetation Index (NDVI), fractal dimension, and Accumulated Growing Degree Days (AGDDs). In our case, these features are global variable, and measured in the state-level. Moreover, global feature in each Day of Year (DOY) would be impacted by multiple progress stages. Therefore, a mixture model is employed to model the observation probability distribution with all possible stage components. Then, a filtering based algorithm is utilized to estimate the proportion of each progress stage in the real-time. Experiments are conducted in the states of Iowa, Illinois and Nebraska in the USA, and our results are assessed and validated by the Crop Progress Reports (CPRs) of the National Agricultural Statistics Service (NASS). Finally, a quantitative comparison and analysis between our method and spectral pixel-wise based methods is presented. The results demonstrate the feasibility of the proposed method for the estimation of corn progress stages. The proposed method could be used as a supplementary tool in aid of field survey. Moreover, it also can be used to establish the progress stage estimation model for different types of crops.
Internal Calibration Förster Resonance Energy Transfer Assay: A Real-Time Approach for Determining Protease Kinetics
Authors: Jiang Ling , Liu Yan , Song Yang , Saavedra Amanda , Pan Songqin , Xiang Wensheng , Liao Jiayu
Published: April 2013

Förster resonance energy transfer (FRET) technology has been widely used in biological and biomedical research. This powerful tool can elucidate protein interactions in either a dynamic or steady state. We recently developed a series of FRET-based technologies to determine protein interaction dissociation constant and for use in high-throughput screening assays of SUMOylation. SUMO (small ubiquitin-like modifier) is conjugated to substrates through an enzymatic cascade. This important posttranslational protein modification is critical for multiple biological processes. Sentrin/SUMO-specific proteases (SENPs) act as endopeptidases to process the pre-SUMO or as isopeptidases to deconjugate SUMO from its substrate. Here, we describe a novel quantitative FRET-based protease assay for determining the kinetics of SENP1. Our strategy is based on the quantitative analysis and differentiation of fluorescent emission signals at the FRET acceptor emission wavelengths. Those fluorescent emission signals consist of three components: the FRET signal and the fluorescent emissions of donor (CyPet) and acceptor (YPet). Unlike our previous method in which donor and acceptor direct emissions were excluded by standard curves, the three fluorescent emissions were determined quantitatively during the SENP digestion process from onesample. New mathematical algorithms were developed to determine digested substrate concentrations directly from the FRET signal and donor/acceptor direct emissions. The kinetic parameters, kcat, KM, and catalytic efficiency (kcat/KM) of SENP1 catalytic domain for pre-SUMO1/2/3 were derived. Importantly, the general principles of this new quantitative methodology of FRET-based protease kinetic determinations can be applied to other proteases in a robust and systems biology approach.
Development of a Sensor System for the Determination of Sanitary Quality of Grapes
Authors: Zanardi Chiara , Ferrari Luca , Zanfrognini Barbara , Pigani Laura , Terzi Fabio , Cattini Stefano , Rovati Luigi , Seeber Renato
Published: April 2013

n instrument for the automatic quantification of glycerol in grapes has been developed. We verify here that this analyte can be used as a benchmark of a serious disease affecting the grapevines, namely Botrytis cinerea. The core of the instrument is an amperometric biosensor consisting of a disposable screen printed electrode, generating the analytical signal thanks to a bi-enzymatic process involving glycerol dehydrogenase and diaphorase. The full automation of the analysis is realised by three micropumps and a microprocessor under control of a personal computer. The pumps allow the correct and constant dilution of the grape juice with a buffer solution also containing [Fe(CN)6]3− redox mediator and the injection of NAD+ cofactor when the baseline signal reaches a steady state; the instrument leads to automated reading of the analytical signal and the consequent data treatment. Although the analytical method is based on an amperometric technique that, owing to heavy matrix effects, usually requires an internal calibration, the analyses indicate that a unique external calibration is suitable for giving accurate responses for any grapes, both white and black ones.
Molecular Electric Transducers as Motion Sensors: A Review
Authors: Huang Hai , Agafonov Vadim , Yu Hongyu
Published: April 2013

This article reviews the development of a new category of motion sensors including linear and angular accelerometers and seismometers based on molecular electronic transducer (MET) technology. This technology utilizes a liquid not only as an inertial mass, but also as one of the main elements in the conversion of mechanical motion into electric current. The amplification process is similar to that in a vacuum triode. Therefore, it is possible to achieve signal amplification close to 108. Motion sensors demonstrating wide frequency and dynamic range and sensitivity that are one to two orders of magnitude better than MEMS devices of the same size have been developed.
A Threat- and Efficacy-Based Framework to Understand Confidence in Vaccines among the Public Health Workforce
Authors: Barnett Daniel , Errett Nicole , Rutkow Lainie
Published: April 2013

The Extended Parallel Process Model (EPPM) is an established threat- and efficacy-based behavioral framework for understanding health behaviors in the face of uncertain risk. A growing body of research has applied this model to understand these behaviors among the public health workforce. In this manuscript, we aim to explore the application of this framework to the public health workforce, with a novel focus on their confidence in vaccines and perceptions of vaccine injury compensation mechanisms. We characterize specific connections between EPPM’s threat and efficacy dimensions and relevant vaccine policy frameworks and highlight how these connections can usefully inform training interventions for public health workers to enhance their confidence in these vaccine policy measures.
Anticipated HIV Vaccine Acceptability among Sexually Active African-American Adult Women
Authors: Painter Julia , Cene-Kush Clare , Conner Alaina , Cwiak Carrie , Haddad Lisa , Mulligan Mark , DiClemente Ralph
Published: April 2013

An HIV vaccine, once it becomes available, could reduce vulnerability to HIV among African-American women. The purpose of this study was to assess determinants of HIV vaccine acceptability among African-American women across hypothetical levels of vaccine efficacy. Participants were recruited from a hospital-based family planning clinic in Atlanta, GA serving low-income patients (N = 321). Data were collected from audio-computer assisted surveys administered in the clinic waiting room. Psychosocial survey items were guided by Risk Homeostasis Theory (RHT) and Social Cognitive Theory (SCT). Multivariate logistic regression was used to identify determinants of acceptability for two hypothetical HIV vaccines with 50% and 90% efficacy. Overall, 63% of participants would accept a vaccine with 50% efficacy and 85% would accept a vaccine with 90% efficacy. In multivariate analyses, odds of acceptability for a vaccine with 50% efficacy were higher among participants with greater perceived HIV vaccine benefits (AOR = 1.13, p < 0.001) and lower among participants with more than high school education (AOR = 0.47, p = 0.033) and greater perceived costs of HIV vaccination (AOR = 0.95, p = 0.010). Odds of acceptability for a vaccine with 90% efficacy were higher among participants with greater perceived costs of unprotected sex (AOR = 1.08, p = 0.026), HIV vaccine benefits (AOR = 1.23, p < 0.001) and self-efficacy for sex refusal (AOR = 1.11, p = 0.044). HIV vaccine acceptability was high, particularly for a vaccine with 90% efficacy. Findings suggest that demographic and psychosocial factors may impact acceptability of an eventual HIV vaccine. Once an HIV vaccine is available, interventions to maximize uptake may benefit from using RHT and SCT constructs to target relevant psychosocial factors, such as perceived benefits and perceived costs of vaccination.
CO2 Emission Factor for Rainwater and Reclaimed Water Used in Buildings in Japan
Authors: Shimizu Yasutoshi , Dejima Satoshi , Toyosada Kanako
Published: April 2013

From the standpoint of the preservation of water resources, rainwater and reclaimed water have been widely used in buildings in many countries. However, the CO2 emission factors of these two waters—factors that determine their environmental impacts—have not been calculated. In a previous study, the CO2 emission factor of water for waterworks and sewer systems was determined. In this paper, we evaluate the emission factors of rainwater and reclaimed water in the same manner. First, the emission factor for pumping water in buildings is determined using published values for operating performances. About half of the residential dwellings in Japan are multistory apartments, and these apartments use pumps for the delivery of water. The emission factor of pumping is calculated as 0.69 kg CO2/m3, which adds 16% to the emission factor of waterworks and sewer systems. Next, the CO2 emission factors of rainwater and reclaimed water are calculated for different water delivery cases in buildings. As a result, it is found that the use of reclaimed water increases CO2 emissions by 62%, compared to the use of ordinary water.
Noninvasive in Vivo Tracking of Mesenchymal Stem Cells and Evaluation of Cell Therapeutic Effects in a Murine Model Using a Clinical 3.0 T MRI
Authors: Drey Florian , Choi Yeong-Hoon , Neef Klaus , Ewert Birgit , Tenbrock Arne , Treskes Philipp , Bovenschulte Henning , Liakopoulos Oliver J. , Brenkmann Meike , Stamm Christof , Wittwer Thorsten , Wahlers Thorsten
Published: April 2013

Cardiac cell therapy with mesenchymal stem cells (MSCs) represents a promising treatment approach for endstage heart failure. However, little is known about the underlying mechanisms and the fate of the transplanted cells. The objective of the presented work is to determine the feasibility of magnetic resonance imaging (MRI) and in vivo monitoring after transplantation into infarcted mouse hearts using a clinical 3.0 T MRI device. The labeling procedure of bone marrow-derived MSCs with micron-sized paramagnetic iron oxide particles (MPIOs) did not affect the viability of the cells and their cell type-defining properties when compared to unlabeled cells. Using a clinical 3.0 T MRI scanner equipped with a dedicated small animal solenoid coil, 105 labeled MSCs could be detected and localized in the mouse hearts for up to 4 weeks after intramyocardial transplantation. Weekly ECG-gated scans using T1-weighted sequences were performed, and left ventricular function was assessed. Histological analysis of hearts confirmed the survival of labeled MSCs in the target area up to 4 weeks after transplantation. In conclusion, in vivo tracking of labeled MSCs using a clinical 3.0 T MRI scanner is feasible. In combination with assessment of heart function, this technology allows the monitoring of the therapeutic efficacy of regenerative therapies in a small animal model.
Magnetic Resonance Imaging of Human Dental Pulp Stem Cells in Vitro and in Vivo
Authors: Struys T. , Ketkar-Atre A. , Gervois P. , Leten C. , Hilkens P. , Martens W. , Bronckaers A. , Dresselaers T. , Politis C. , Lambrichts I. , Himmelreich U.
Published: April 2013

Recent advances in stem cell research have shown the promising nature of mesenchymal stem cells as plausible candidates for cell-based regenerative medicine. Many studies reported the use of human dental pulp stem cells (hDPSCs), which possess self-renewal capacity, high proliferation potential, and the ability to undergo multilineage differentiation. Together with this therapeutic approach, development of effective, noninvasive and nontoxic imaging techniques for visualizing and tracking the cells in vivo is crucial for the evaluation and improvement of stem cell therapy. Magnetic resonance imaging (MRI) is one of the most powerful diagnostic imaging techniques currently available for in vivo diagnosis and has been proposed as the most attractive modality for monitoring stem cell migration. The aim of this study was to investigate the labeling efficiency of hDPSCs using superparamagnetic iron oxide (SPIO) particles in order to allow visualization using in vitro and in vivo MRI without influencing cellular metabolism. MRI and transmission electron microscopy (TEM) showed optimal uptake with low SPIO concentrations of 15 μg/ml in combination with 0.75 μg/ml poly-l-lysine (PLL) resulting in more than 13 pg iron/cell and an in vitro detection limit of 50 labeled cells/μl. Very low SPIO concentrations in the culture medium resulted in extremely high labeling efficiency not reported before. For these conditions, tetrazolium salt assays showed no adverse effects on cell viability. Furthermore, in vivo MRI was performed to detect labeled hDPSCs transplanted into the brain of Rag 2-γ C immune-deficient mice. Transplanted cells did not show any signs of tumorgenecity or teratoma formation during the studied time course. We have reported on a labeling and imaging strategy to visualize human dental pulp stem cells in vivo using MRI. These data provide a solid base to allow cell tracking in future regenerative studies in the brain longitudinally.
Development of Experimental Tumors Formed by Mouse and Human Embryonic Stem and Teratocarcinoma Cells after Subcutaneous and Intraperitoneal Transplantations into Immunodeficient and Immunocompetent Mice
Authors: Gordeeva O. F. , Nikonova T. M.
Published: April 2013

Pluripotent stem cells represent an attractive cell source for regenerative medicine. However, the risk of teratoma formation after transplantation restricts their clinical application. Therefore, to adequately evaluate the potential risk of tumorigenicity after cell transplantation into human tissues, effective animal transplantation assays need to be developed. We performed a multiparameter (cell number, transplantation site, cell type, host) comparative analysis of the efficiency of tumor development after transplantation of mouse and human embryonic stem (ES) cells and their malignant counterparts, teratocarcinoma (EC) cells, into animal recipients and revealed several key correlations. We found that the efficiency of tumor growth was higher after intra-peritoneal than after subcutaneous transplantations of all cell lines studied. The minimal cell numbers sufficient for tumor growth in immunodeficient nude mice were 100-fold lower for intraperitoneal than for subcutaneous transplantations of mouse and human ES cells (103 vs. 105 and 104 vs. 106, respectively). Moreover, mouse ES and EC cells formed tumors in immunodeficient and immunocompetent mice more effectively than human ES and EC cells. After intraperitoneal transplantation of 103, 104, and 105 mouse ES cells, teratomas developed in 83%, 100%, and 100% of nude mice, whereas after human ES cell transplantation, teratomas developed in 0%, 17%, and 60%, respectively. In addition, malignant mouse and human EC cells initiated tumor growth after intraperitoneal transplantation significantly faster and more effectively than ES cells. Mouse and human ES cells formed different types of teratomas containing derivatives of three germ layers but different numbers of undifferentiated cells. ES cell-like sublines with differentiation potential similar to the parental cell line were recloned only from mouse, but not from human, ES cell teratomas. These findings provide new information about the possibility and efficiency of tumor growth after transplantation of pluripotent stem cells. This information allows one to predict and possibly prevent the possible risks of tumorigenicity that could arise from stem cell therapeutics.
Effects of Vitamin C on Cytotherapy-Mediated Muscle Regeneration
Authors: Kim Ah-Young , Lee Eun-Mi , Lee Eun-Joo , Min Chang-Woo , Kang Kyung-Ku , Park Jin-Kyu , Hong Il-Hwa , Ishigami Akihito , Tremblay Jacques P. , Jeong Kyu-Shik
Published: April 2013

Skeletal muscles are the largest organs in the human body, and several therapeutic trials have been conducted that included stem cell transplantation to regenerate damaged or wasted muscles. It is well known that it is essential to make a favorable microenvironment (stem cell niche) to induce the proper differentiation of the transplanted stem cells. Some drugs, such as losartan (angiotensin II type I blocker), enhance the therapeutic effects of transplanted stem cells by inhibiting fibrosis. In this study, we hypothesized that another substance, vitamin C (ascorbic acid), might improve the niche for stem cell transplantation based on its potent antioxidant effects. In both gross and microscopic observations, vitamin C-depleted mice exhibited more incomplete regeneration of damaged muscles than those treated with vitamin C. Carbonylated protein groups, which are the end products of oxidative stress, were detected in all experimental groups; however, the vitamin C-depleted groups exhibited a more potent positive reaction than that of the vitamin C-supplied groups. The difference is clearer in the presence of transplanted stem cells. Moreover, the serum total vitamin C level and the ascorbic acid (AA) to dehydroascorbic acid (DHA) ratio also were decreased in the presence of transplanted adipose-derived stem cells (ASCs). Taken together, these data can be considered as proof of vitamin C utilization by cells in vivo. The vitamin C-supplied groups displayed more severe fibrosis than that of the vitamin C-depleted groups. Since vitamin C is a major cofactor for the collagen synthesis, its deficiency resulted in reduced fibrosis. In conclusion, we demonstrated that vitamin C not only has a positive effect on adjusting the stem cell niche to boost muscle regeneration but also has an adverse aspect due to its profibrotic effect.
Improvement of Pig Islet Function by In Vivo Pancreatic Tissue Remodeling: A “Human-Like” Pig Islet Structure with Streptozotocin Treatment
Authors: Vériter Sophie , Aouassar Najima , Beaurin Gwen , Goebbels Rose-Marie , Gianello Pierre , Dufrane Denis
Published: April 2013

Pig islets demonstrate significantly lower insulin secretion after glucose stimulation than human islets (stimulation index of ~12 vs. 2 for glucose 1 and 15 mM, respectively) due to a major difference in β- and α-cell composition in islets (60% and 25% in humans and 90% and 8% in pigs, respectively). This leads to a lower rise in 3′,5′-cyclic adenosine monophosphate (cAMP) in pig β-cells. Since glucagon is the major hormonal effector of cAMP in β-cells, we modified pig islet structure in vivo to increase the proportion of α-cells per islet and to improve insulin secretion. Selected doses (0, 30, 50, 75, and 100 mg/kg) of streptozotocin (STZ) were intravenously injected in 32 young pigs to assess pancreatic (insulin and glucagon) hormone levels, islet remodeling (histomorphometry for α- and β-cell proportions), and insulin and glucagon secretion in isolated islets. Endocrine structure and hormonal content of pig islets were compared with those of human islets. The dose of STZ was significantly correlated with reductions in pancreatic insulin content ( p < 0.05, r2 = 0.77) and the proportion of β-cells ( p < 0.05, r2 = 0.88). A maximum of 50 mg/kg STZ was required for optimal structure remodeling, with an increased proportion of α-cells per islet (26% vs. 48% α-cells per islet for STZ <50 mg/kg vs. >75 mg/kg; p < 0.05) without β-cell dysfunction. Three months after STZ treatment (30/50 mg/kg STZ), pig islets were isolated and compared with isolated control islets (0 mg/kg STZ). Isolated islets from STZ-treated (30/50 mg/kg) pigs had a higher proportion of α-cells than those from control animals (32.0% vs. 9.6%, respectively, p < 0.05). After in vitro stimulation, isolated islets from STZ-treated pigs demonstrated significantly higher glucagon content (65.4 vs. 21.0 ng/ml, p < 0.05) and insulin release (144 μU/ml) than nontreated islets (59 μU/ml, p < 0.05), respectively. Low-dose STZ (<50 mg/kg) can modify the structure of pig islets in vivo and improve insulin secretion after isolation.
A look underneath the SiO2/4H-SiC interface after N2O thermal treatments
Authors: Fiorenza Patrick , Giannazzo Filippo , Swanson Lukas K , Frazzetto Alessia , Lorenti Simona , Alessandrino Mario S , Roccaforte Fabrizio
Published: April 2013

The electrical compensation effect of the nitrogen incorporation at the SiO2/4H-SiC (p-type) interface after thermal treatments in ambient N2O is investigated employing both scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM). SSRM measurements on p-type 4H-SiC areas selectively exposed to N2O at 1150 °C showed an increased resistance compared to the unexposed ones; this indicates the incorporation of electrically active nitrogen-related donors, which compensate the p-type doping in the SiC surface region. Cross-sectional SCM measurements on SiO2/4H-SiC metal/oxide/semiconductor (MOS) devices highlighted different active carrier concentration profiles in the first 10 nm underneath the insulator–substrate interface depending on the SiO2/4H-SiC roughness.

The electrically active incorporated nitrogen produces both a compensation of the acceptors in the substrate and a reduction of the interface state density (Dit). This result can be correlated with the 4H-SiC surface configuration. In particular, lower Dit values were obtained for a SiO2/SiC interface on faceted SiC than on planar SiC. These effects were explained in terms of the different surface configuration in faceted SiC that enables the simultaneous exposition at the interface of atomic planes with different orientations.
Reductions of aldehydes and ketones with a readily available N-heterocyclic carbene borane and acetic acid
Authors: Lamm Vladimir , Pan Xiangcheng , Taniguchi Tsuyoshi , Curran Dennis P
Published: April 2013

Acetic acid promotes the reduction of aldehydes and ketones by the readily available N-heterocyclic carbene borane, 1,3-dimethylimidazol-2-ylidene borane. Aldehydes are reduced over 1–24 h at room temperature with 1 equiv of acetic acid and 0.5 equiv of the NHC-borane. Ketone reductions are slower but can be accelerated by using 5 equiv of acetic acid. Aldehydes can be selectively reduced in the presence of ketones. On a small scale, products are isolated by evaporation of the reaction mixture and direct chromatography.
Essai sur la dynamique d'assimilation des innovations managériales
Authors: Godowski Christophe
Published: April 2013

Les approches par activités ont fait l’objet depuis maintenant plus d’une décennie d’une profusion d’articles et d’ouvrages. Cependant, leur diffusion dans les entreprises industrielles et de services est en décalage avec l’intérêt qu’elles ont suscité auprès des milieux universitaires et professionnels. Diverses enquêtes auprès de professionnels nous laissent à penser que le problème de l’utilisation se situe au niveau de l’assimilation par l’organisation de cette innovation. Cette contribution propose un essai sur la dynamique d’assimilation des approches par activités. L’article cherche à expliquer la lente et difficile assimilation des approches par activités par l’organisation en liant la théorie de la traduction de Callon et Latour et la théorie de la gestion du système d’information pour le management. Ce cadre conceptuel met en évidence l’importance de ne pas considérer l’innovation managériale comme une boîte noire mais comme un ensemble d’éléments en interaction dont il faut assurer la cohérence.
Les techniques de comptabilité environnementale, entre innovations comptables et innovations managériales
Authors: Lafontaine Jean-Philippe
Published: April 2013

De plus en plus d’entreprises prennent en compte l’environnement naturel dans leur gestion, ce qui entraîne une modification profonde des outils, des processus et des pratiques. Dans le champ de la comptabilité, de nombreuses recherches et expériences ont été consacrées à l’émergence de la comptabilité environnementale (CE). Cet article s’interroge sur la nature de la CE. Certains arguments extraits de la littérature confèrent assurément le statut d’innovation managériale à la CE. En revanche, des témoignages de professionnels de la comptabilité et de l’environnement semblent montrer que la CE dépasse le champ de la comptabilité et qu’il est difficile de considérer toutes les techniques de CE comme des innovations comptables.
Organisation matricielle et coordination transversale : le budget demeure l'outil privilégié
Authors: Thomas Catherine
Published: April 2013

La coordination transversale renforce l’autonomie des acteurs et leur nécessaire coopération dans l’acte productif. Elle remet ainsi en cause deux hypothèses clés sur lesquelles repose le contrôle de gestion traditionnel : la modélisation de la performance globale comme une addition de performances locales et la logique de responsabilité individuelle. Nous proposons d’étudier, à partir de l’exemple d’une division d’un groupe industriel européen, sous quelles conditions un usage innovant du processus budgétaire peut en faire le vecteur de la mise en place d’une coordination transversale.
Wireless Security
Authors: Kaleem Faisal , Yen Kang K.
Published: April 2013

The purpose of this chapter is to educate individuals about the inherent security risks and vulnerabilities of common and emerging wireless technologies and to provide them with some of the best practices used in securing or minimizing these associated risks.
Forensics Challenges for Mobile Phone Security
Authors: Khelalfa Halim M.
Published: April 2013

First, the author reviews the currently used guidelines and procedures in digital forensic investigations, and then presents their current adaptations to mobile phone forensics, including criteria for the selection of forensics tool for mobile phone. Due to the world popularity of GSM phones, a detailed description of the SIM file system is presented. The forensic strength and weaknesses of the classes of physical and logical forensic tools are discussed .Current approaches to overcome the impediments of both classes are reviewed in terms of usability and forensic soundness. Then, the newest challenge to the digital forensic community, anti-forensics (AF) is raised, including the risks faced by mobile phone forensics investigation. Finally, the author addresses the issue of current research as well as trends on mobile phone forensics.
Identity-Based Cryptography
Authors: Torres Jenny , Nogueira Michele , Pujolle Guy
Published: April 2013

Since computer systems and communication become each time more pervasive, information security takes attention, requiring guarantees for data authentication, integrity and confidentiality. Pervasive communication and computer systems intend to provide access to information and services anytime and anywhere, demanding cryptographic systems more practical and that consider the characteristics of emerging network paradigms, such as wireless communication, device constraints and mobility. Identity-Based Cryptography (IBC) is an asymmetric key cryptographic technology that employs as user’s public key any unique information related to the identity of the user. IBC efficiently manages keying material and provides an easy way to issue a pair of keys applying user information. However, it assumes the existence of a Trusted Third Party (TTP), called Private Key Generator (PKG), which is responsible for generating the corresponding user private key. Relying on a TTP and using an identity as the base of the scheme result in different weaknesses on the system, as the inherent key escrow problem. This chapter investigates those weaknesses, and it points out the stat-of-the-art of proposed solutions to avoid them. This chapter also provides an overview of Identity-Based Encryption (IBE), Identity-Based Signature (IBS) and Identity-Based Key Agreement (IBKA), emphasizing IBE due to being an open problem for many years. This chapter concludes highlighting IBC applications and future trends.
Risk Assessment and Real Time Vulnerability Identification in IT Environments
Authors: Peotta de Melo Laerte , Gondim Paulo Roberto de Lira
Published: April 2013

Contrary to static models of risk analysis, the authors propose a pro-active framework for identifying vulnerabilities and assessing risk in real-time. Instead of searching for vulnerabilities from an external point of view, where the information is obtained by simply exploring a digital asset (computational system composed of hardware and software), the authors propose that software agents (sensors) capable of providing application, configuration and location information be incorporated into assets. Any observed changes, such as physical location, software update or installation, hardware modifications, changes in security policy and others, will be immediately reported by the agent, in a pro-active manner, to a central repository. It is possible to assess risk in a certain environment comparing databases of rules and known vulnerabilities with information about each asset, collected by the sensors and stored in the central repository.
Microbial contamination of pumice used in dental laboratories
Authors: Firoozeh Farzaneh , Zibaei Mohammad , Zendedel Abolfazl , Rashidipour Hushang , Kamran Aziz
Published: April 2013

Dental appliances as well as sending and receiving prosthesis from laboratories are potential sources of cross-contamination for technicians, dentists, patients and can transmit different infectious agents as well. This study was conducted to determine the types of the microorganisms in pumice powder and pumice slurry used in dental laboratory in order to evaluate necessary disinfection control procedure in the dental settings. Twenty-four active dental laboratories of Khorram Abad participated in our study. Samples were randomly collected from prosthesis polishing containers in sterilized condition and were immediately sent to microbiology laboratory. Specimens were cultured on selective bacterial and fungal media in order to determine the microorganisms. Both oral and non-oral bacteria were recovered from pumice samples as follows: Staphylococcus aureus (15.4%), Streptococcus viridance (10.8%), Bacillus cereus (18.7%), Pseudomonas aeruginosa (12.8%), Diphtheriods (7.3%), Enterobacter cloace (4.3%), Escherichia coli (13.1%), Klebsiella pneumonia (5.4%), and Acinetobacter spp. (12.2%). The isolated fungi included Candida albicans (36.7%), other yeasts (17.3%), Fusarium spp. (13.8%), Aspergilus spp. (22.4%) and Penicillium spp. (9.8%). This study showed that polishing pumices in the form of powder or slurry were contaminated with different oral and non-oral bacteria and also fungi. Therefore, the chance of cross-contamination still severely exists, and measures should be conducted to prevent the contamination of predisposed people such as technicians, dentists and patients.