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Sample records for bioassay neighboring analysis

  1. k-Nearest Neighbors Algorithm in Profiling Power Analysis Attacks

    Directory of Open Access Journals (Sweden)

    Z. Martinasek

    2016-06-01

    Full Text Available Power analysis presents the typical example of successful attacks against trusted cryptographic devices such as RFID (Radio-Frequency IDentifications and contact smart cards. In recent years, the cryptographic community has explored new approaches in power analysis based on machine learning models such as Support Vector Machine (SVM, RF (Random Forest and Multi-Layer Perceptron (MLP. In this paper, we made an extensive comparison of machine learning algorithms in the power analysis. For this purpose, we implemented a verification program that always chooses the optimal settings of individual machine learning models in order to obtain the best classification accuracy. In our research, we used three datasets, the first containing the power traces of an unprotected AES (Advanced Encryption Standard implementation. The second and third datasets are created independently from public available power traces corresponding to a masked AES implementation (DPA Contest v4. The obtained results revealed some interesting facts, namely, an elementary k-NN (k-Nearest Neighbors algorithm, which has not been commonly used in power analysis yet, shows great application potential in practice.

  2. Sample preparation for combined chemical analysis and bioassay application in water quality assessment

    NARCIS (Netherlands)

    Kolkman, A.; Schriks, M.; Brand, W; Bäuerlein, P.S.; van der Kooi, M.M.E.; van Doorn, R.H.; Emke, E.; Reus, A.; van der Linden, S.; de Voogt, P.; Heringa, M.B.

    2013-01-01

    The combination of in vitro bioassays and chemical screening can provide a powerful toolbox to determine biologically relevant compounds in water extracts. In this study, a sample preparation method is evaluated for the suitability for both chemical analysis and in vitro bioassays. A set of 39

  3. TERRITORIAL DISPUTES BETWEEN RUSSIA AND NEIGHBORING COUNTRIES. COMPARATIVE ANALYSIS

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    Aleksander Nikolaevich Kharybin

    2018-01-01

    Full Text Available The article gives a brief analysis of Russia’s territorial disputes, the author notes that territorial disputes and conflicts affect almost all sections of the border: there are no territorial problems only on the border with Belarus, South Ossetia and Mongolia. Practical recommendations are given to optimize Russia’s foreign policy, as well as scenarios of the most probable development of the situation. By the method of comparative analysis, the author notes the common features of all the disputes on the Russian border: in all problem points, either the status quo is preserved or concessions have been made by Russia, in most cases the disputed territory is under the jurisdiction of Russia, with most of the states there is no border treaty. In situations where the contract is concluded, this also in many cases does not cease the territorial dispute; in most of the disputes, the active role of the United States is seen as an actor of destabilizing the situation.

  4. Error analysis for RADAR neighbor matching localization in linear logarithmic strength varying Wi-Fi environment.

    Science.gov (United States)

    Zhou, Mu; Tian, Zengshan; Xu, Kunjie; Yu, Xiang; Wu, Haibo

    2014-01-01

    This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs) in logarithmic received signal strength (RSS) varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs) as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future.

  5. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2014-01-01

    Full Text Available This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs in logarithmic received signal strength (RSS varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future.

  6. Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

    Directory of Open Access Journals (Sweden)

    Workalemahu M. Berhanu

    2012-07-01

    Full Text Available The chemical similarity of antibacterial cyclic peptides and peptidomimetics was studied in order to identify new promising cyclic scaffolds. A large descriptor space coupled with cluster analysis was employed to digitize known antibacterial structures and to gauge the potential of new peptidomimetic macrocycles, which were conveniently synthesized by acylbenzotriazole methodology. Some of the synthesized compounds were tested against an array of microorganisms and showed antibacterial activity against Bordetella bronchistepica, Micrococcus luteus, and Salmonella typhimurium.

  7. Selective extraction of actinides by calixarenes: application to bioassay analysis

    International Nuclear Information System (INIS)

    Boulet, B.

    2006-01-01

    In the context of nuclear workers monitoring, the aim of this PhD was to selectively isolate U, Pu, and Am from urine to propose a new analytical procedure to the Medical and Biology Analysis Laboratories. The 1,3,5-OCH 3 -2,4,6-OCH 2 CONHOH-p-tert-butyl-calix[6]arene molecule has been selected as a promising extractant for U, Pu, and Am. Its physico-chemical properties and its affinity for UO 2 2+ have been studied through two approaches, one theoretical (molecular modelling at DFT level), and one experimental. The extractions of the three actinides by the hydroxamic calix[6]arene were quantitative in liquid-liquid and solid-liquid systems. Their separation has also been shown possible and efficient. After optimization, the proposed procedure should allow the laboratories to carry out the chemical treatment of urine, before the measurement, in one day instead of the three days needed nowadays. (author)

  8. Bioassay Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Bioassay Laboratory is an accredited laboratory capable of conducting standardized and innovative environmental testing in the area of aquatic ecotoxicology. The...

  9. [Quality evaluation of rhubarb dispensing granules based on multi-component simultaneous quantitative analysis and bioassay].

    Science.gov (United States)

    Tan, Peng; Zhang, Hai-Zhu; Zhang, Ding-Kun; Wu, Shan-Na; Niu, Ming; Wang, Jia-Bo; Xiao, Xiao-He

    2017-07-01

    This study attempts to evaluate the quality of Chinese formula granules by combined use of multi-component simultaneous quantitative analysis and bioassay. The rhubarb dispensing granules were used as the model drug for demonstrative study. The ultra-high performance liquid chromatography (UPLC) method was adopted for simultaneously quantitative determination of the 10 anthraquinone derivatives (such as aloe emodin-8-O-β-D-glucoside) in rhubarb dispensing granules; purgative biopotency of different batches of rhubarb dispensing granules was determined based on compound diphenoxylate tablets-induced mouse constipation model; blood activating biopotency of different batches of rhubarb dispensing granules was determined based on in vitro rat antiplatelet aggregation model; SPSS 22.0 statistical software was used for correlation analysis between 10 anthraquinone derivatives and purgative biopotency, blood activating biopotency. The results of multi-components simultaneous quantitative analysisshowed that there was a great difference in chemical characterizationand certain differences inpurgative biopotency and blood activating biopotency among 10 batches of rhubarb dispensing granules. The correlation analysis showed that the intensity of purgative biopotency was significantly correlated with the content of conjugated anthraquinone glycosides (Pquantitative analysis and bioassay can achieve objective quantification and more comprehensive reflection on overall quality difference among different batches of rhubarb dispensing granules. Copyright© by the Chinese Pharmaceutical Association.

  10. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    International Nuclear Information System (INIS)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng

    2014-01-01

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy

  11. Coupling of In Vitro Bioassays with Planar Chromatography in Effect-Directed Analysis.

    Science.gov (United States)

    Weiss, Stefan C; Egetenmeyer, Nicole; Schulz, Wolfgang

    Modern analytical test methods increasingly detect anthropogenic organic substances and their transformation products in water samples and in the environment. The presence of these compounds might pose a risk to the aquatic environment. To determine a possible (eco)toxicological risk, aquatic samples are tested using various bioassays, including sub-organismic assays such as the luminescent bacteria inhibition test, the acetylcholinesterase inhibition test, and the umu-test. The effect-directed analysis (EDA) combines physicochemical separation methods with biological (in vitro) tests. High-performance thin-layer chromatography (HPTLC) has proved to be particularly well suited for the separation of organic compounds and the subsequent analysis of effects by the application of the biotests directly on the surface of the HPTLC plate. The advantage of using HPTLC in comparison to high-performance liquid chromatography (HPLC) for EDA is that the solvent which is used as a mobile phase during chromatography is completely evaporated after the separation and therefore can no longer influence the applied bioassays.A prioritization during the complex identification process can be achieved when observed effects are associated with the separated zones in HPTLC. This increases the probability of identifying the substance responsible for an adverse effect from the multitude of organic trace substances in environmental samples. Furthermore, by comparing the pattern of biological effects of a separated sample, it is possible to track and assess changes in biological activity over time, over space, or in the course of a process, even without identifying the substance. HPTLC has already been coupled with various bioassays.Because HPTLC is a very flexible system, various detection techniques can be used and combined. In addition to the UV/Vis absorption and fluorescence measurements, TLC can also be coupled with a mass spectrometer (MS) for compound identification. In addition

  12. Seismic clusters analysis in Northeastern Italy by the nearest-neighbor approach

    Science.gov (United States)

    Peresan, Antonella; Gentili, Stefania

    2018-01-01

    The main features of earthquake clusters in Northeastern Italy are explored, with the aim to get new insights on local scale patterns of seismicity in the area. The study is based on a systematic analysis of robustly and uniformly detected seismic clusters, which are identified by a statistical method, based on nearest-neighbor distances of events in the space-time-energy domain. The method permits us to highlight and investigate the internal structure of earthquake sequences, and to differentiate the spatial properties of seismicity according to the different topological features of the clusters structure. To analyze seismicity of Northeastern Italy, we use information from local OGS bulletins, compiled at the National Institute of Oceanography and Experimental Geophysics since 1977. A preliminary reappraisal of the earthquake bulletins is carried out and the area of sufficient completeness is outlined. Various techniques are considered to estimate the scaling parameters that characterize earthquakes occurrence in the region, namely the b-value and the fractal dimension of epicenters distribution, required for the application of the nearest-neighbor technique. Specifically, average robust estimates of the parameters of the Unified Scaling Law for Earthquakes, USLE, are assessed for the whole outlined region and are used to compute the nearest-neighbor distances. Clusters identification by the nearest-neighbor method turn out quite reliable and robust with respect to the minimum magnitude cutoff of the input catalog; the identified clusters are well consistent with those obtained from manual aftershocks identification of selected sequences. We demonstrate that the earthquake clusters have distinct preferred geographic locations, and we identify two areas that differ substantially in the examined clustering properties. Specifically, burst-like sequences are associated with the north-western part and swarm-like sequences with the south-eastern part of the study

  13. Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials

    International Nuclear Information System (INIS)

    Thompson, A.P.; Swiler, L.P.; Trott, C.R.; Foiles, S.M.; Tucker, G.J.

    2015-01-01

    We present a new interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum

  14. Classification and analysis of a large collection of in vivo bioassay descriptions.

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    Magdalena Zwierzyna

    2017-07-01

    Full Text Available Testing potential drug treatments in animal disease models is a decisive step of all preclinical drug discovery programs. Yet, despite the importance of such experiments for translational medicine, there have been relatively few efforts to comprehensively and consistently analyze the data produced by in vivo bioassays. This is partly due to their complexity and lack of accepted reporting standards-publicly available animal screening data are only accessible in unstructured free-text format, which hinders computational analysis. In this study, we use text mining to extract information from the descriptions of over 100,000 drug screening-related assays in rats and mice. We retrieve our dataset from ChEMBL-an open-source literature-based database focused on preclinical drug discovery. We show that in vivo assay descriptions can be effectively mined for relevant information, including experimental factors that might influence the outcome and reproducibility of animal research: genetic strains, experimental treatments, and phenotypic readouts used in the experiments. We further systematize extracted information using unsupervised language model (Word2Vec, which learns semantic similarities between terms and phrases, allowing identification of related animal models and classification of entire assay descriptions. In addition, we show that random forest models trained on features generated by Word2Vec can predict the class of drugs tested in different in vivo assays with high accuracy. Finally, we combine information mined from text with curated annotations stored in ChEMBL to investigate the patterns of usage of different animal models across a range of experiments, drug classes, and disease areas.

  15. Bioassay-directed chemical analysis and detection of mutagenicity in ambient air of the coke oven.

    Science.gov (United States)

    Dobiás, L; Kůsová, J; Gajdos, O; Vidová, P; Gajdosová, D; Havránková, J; Fried, M; Binková, B; Topinka, J

    1999-09-30

    In the present study, we summarize the results of studies on the mutagenic potential of the main fractions and subfractions of extractable organic material (EOM) in the ambient air at the workplaces of the coke oven. The objective of our experiments was to apply the Bioassay-Directed Chemical Analysis (with the use of the Ames test) for the identification of the differences in the mutagenicity of these fractions, in relationship to the complex mixture of EOM in occupational air. From the evaluation of results, it is possible to deduce the following conclusions: (1) The comparison of the mutagenicity in the main fractions (basic, acidic, neutral) demonstrates the existence of differences in mutagenic potential. Of the total mutagenicity, 20.4% is in the basic fraction, 25.4% in the acidic fraction and 54.2% in the neutral fraction. (2) In general, 90.1% of the mutagenicity found in the basic, acidic and neutral fractions together was associated with the requirement of metabolic activation in vitro (+S9). In the case of the neutral fraction, it was 51.8%. (3) These results also suggest that frameshift mutations are the major component (53.8%) of the total mutagenicity of the main fractions. (4) With regards to the mutagenicity of organic compounds in the neutral fraction it appeared that genotoxicants of its subfractions (slightly and moderately polar and aromatic) play the main role. Carcinogenic aromatic hydrocarbons (PAH) and genotoxic nitrocompounds play an important role as determinants of the mutagenic potential of complex mixtures of harmful compounds in ambient air. This is confirmed first by the results of short-term bacterial tests.

  16. Energy-landscape analysis of the two-dimensional nearest-neighbor φ⁴ model.

    Science.gov (United States)

    Mehta, Dhagash; Hauenstein, Jonathan D; Kastner, Michael

    2012-06-01

    The stationary points of the potential energy function of the φ⁴ model on a two-dimensional square lattice with nearest-neighbor interactions are studied by means of two numerical methods: a numerical homotopy continuation method and a globally convergent Newton-Raphson method. We analyze the properties of the stationary points, in particular with respect to a number of quantities that have been conjectured to display signatures of the thermodynamic phase transition of the model. Although no such signatures are found for the nearest-neighbor φ⁴ model, our study illustrates the strengths and weaknesses of the numerical methods employed.

  17. Integration and Analysis of Neighbor Discovery and Link Quality Estimation in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Marjan Radi

    2014-01-01

    Full Text Available Network connectivity and link quality information are the fundamental requirements of wireless sensor network protocols to perform their desired functionality. Most of the existing discovery protocols have only focused on the neighbor discovery problem, while a few number of them provide an integrated neighbor search and link estimation. As these protocols require a careful parameter adjustment before network deployment, they cannot provide scalable and accurate network initialization in large-scale dense wireless sensor networks with random topology. Furthermore, performance of these protocols has not entirely been evaluated yet. In this paper, we perform a comprehensive simulation study on the efficiency of employing adaptive protocols compared to the existing nonadaptive protocols for initializing sensor networks with random topology. In this regard, we propose adaptive network initialization protocols which integrate the initial neighbor discovery with link quality estimation process to initialize large-scale dense wireless sensor networks without requiring any parameter adjustment before network deployment. To the best of our knowledge, this work is the first attempt to provide a detailed simulation study on the performance of integrated neighbor discovery and link quality estimation protocols for initializing sensor networks. This study can help system designers to determine the most appropriate approach for different applications.

  18. Recombinant Streptomyces clavuligerus strain including cas2 gene production and analysis its antibiotic overproduction by bioassay

    Directory of Open Access Journals (Sweden)

    Zohreh Hojati

    2014-03-01

    Full Text Available Background: Streptomyces clavuligerus is one of the most important strain that produce clavulanic acid that wildly used in combination of strong but sensitive to β-lactamase antibiotics in clinics. The cas2 is one of the important genes in the biosynthesis pathway of clavulanic acid. Materials and Methods: The recombinant construct pMTcas2 which contain cas2 gene is obtained from Isfahan University. Recombinant plasmid extracts from streptomyces lividans and confirm by enzyme digestion. The streptomyces clavuligerus protoplast was prepared and transformation was done by using polyethylene glycol. Transformation was confirmed by plasmid extraction and PCR using cas2 specific primers. Finally, bioassay method was used to survey the effect of extra copy of cas2 on clavulanic acid production. Result: Plasmid extraction was initially carried out and the structure of plasmid was confirmed by digestion. The typical white colony was seen on protoplast recovery culture containing thiostrepton antibiotic and gray spores were detected after one week. Plasmid extraction was done from transformed strain and transformation was confirmed by PCR. The results of the bioassay show that amplification of the cas2 gene in multicopy plasmids resulted in a 4.1 fold increase in clavulanic acid production. Conclusion: The bioassay was done and the diameters of zone of inhibition in control and sample were compared. The results of the bioassay show that amplification of the cas2 gene in multicopy plasmids resulted in a 4.1 fold increase in clavulanic acid production. Overproduction of clavulanic acid decreases the cost of its dependent drug production.

  19. A Bayesian approach to the analysis of quantal bioassay studies using nonparametric mixture models.

    Science.gov (United States)

    Fronczyk, Kassandra; Kottas, Athanasios

    2014-03-01

    We develop a Bayesian nonparametric mixture modeling framework for quantal bioassay settings. The approach is built upon modeling dose-dependent response distributions. We adopt a structured nonparametric prior mixture model, which induces a monotonicity restriction for the dose-response curve. Particular emphasis is placed on the key risk assessment goal of calibration for the dose level that corresponds to a specified response. The proposed methodology yields flexible inference for the dose-response relationship as well as for other inferential objectives, as illustrated with two data sets from the literature. © 2013, The International Biometric Society.

  20. Neighboring and Urbanism: Commonality versus Friendship.

    Science.gov (United States)

    Silverman, Carol J.

    1986-01-01

    Examines a dimension of neighboring that need not assume friendship as the role model. When the model assumes only a sense of connectedness as defining neighboring, then the residential correlation, shown in many studies between urbanism and neighboring, disappears. Theories of neighboring, study variables, methods, and analysis are discussed.…

  1. An algorithm for robust non-linear analysis of radioimmunoassays and other bioassays

    International Nuclear Information System (INIS)

    Normolle, D.P.

    1993-01-01

    The four-parameter logistic function is an appropriate model for many types of bioassays that have continuous response variables, such as radioimmunoassays. By modelling the variance of replicates in an assay, one can modify the usual parameter estimation techniques (for example, Gauss-Newton or Marquardt-Levenberg) to produce parameter estimates for the standard curve that are robust against outlying observations. This article describes the computation of robust (M-) estimates for the parameters of the four-parameter logistic function. It describes techniques for modelling the variance structure of the replicates, modifications to the usual iterative algorithms for parameter estimation in non-linear models, and a formula for inverse confidence intervals. To demonstrate the algorithm, the article presents examples where the robustly estimated four-parameter logistic model is compared with the logit-log and four-parameter logistic models with least-squares estimates. (author)

  2. Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (Symphytum officinale).

    Science.gov (United States)

    Couet, C E; Crews, C; Hanley, A B

    1996-01-01

    Pyrrolizidine alkaloids have been linked to liver and lung cancers and a range of other deleterious effects. As with many natural toxicants, major problems arise in determining the effects of the different members of the class and the importance of various forms of ingestion. In this study we have investigated the levels of pyrrolizidine alkaloids in comfrey (Symphytum officinale), determined the levels in different parts of the plant and in herbal remedies, separated the alkaloids into two main groups--the principal parent alkaloids and the corresponding N-oxides--and, finally, carried out a simple bioassay based upon the mutagenic capability of the separated compounds in a human cell line. We conclude that the part of the plant ingested is important in terms of alkaloid challenge and that the effect of two of the major groups of alkaloids individually is different from that of alkaloids in the whole plant extract.

  3. Application of the luciferase recombinant cell culture bioassay system for the analysis of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Ziccardi, Michael H; Gardner, Ian A; Denison, Michael S

    2002-10-01

    An aryl hydrocarbon (Ah) receptor-based luciferase cell culture bioassay developed to detect 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other halogenated aromatics was modified and optimized to detect and quantitate polycyclic aromatics (PAHs). Twenty-four PAHs were analyzed, and subsequent EC50 and EC20 concentrations (based on the median and 20% TCDD maximal response, respectively) and appropriate induction equivalency factors (calculated by comparison to the response obtained with TCDD) were determined from dose-response experiments. Six compounds were shown to be active in the system, with benzo[k]fluoranthene > benz[a,h]anthracene indeno[1,2,3-cd]pyrene > benzo[a]pyrene > benzo[b]fluoranthene > chrysene. A complex mixture of 16 PAHs was also analyzed using this system, and overall induction equivalency (or 1-EQ) of the mixture was shown to be very similar to that predicted from the sum of the activity estimated for each individual PAH. Overall, our results strongly support the use of this system for the detection and relative quantitation of Ah receptor-active PAHs.

  4. Analysis of streptokinase by validated liquid chromatography methods and correlation with an in vitro bioassay.

    Science.gov (United States)

    Cardoso, Clóvis Dervil Appratto; Perobelli, Rafaela Ferreira; Xavier, Bruna; Maldaner, Fernanda Pavani Stamm; da Silva, Francielle Santos; Dalmora, Sérgio Luiz

    2017-01-01

    Reversed-phase and size-exclusion liquid chromatography methods were validated for the assessment of streptokinase. The reversed-phase method was carried out on a Jupiter C 4 column (250 mm × 4.6 mm id) maintained at 25°C. The mobile phase consisted of 50 mM sodium sulfate solution pH 7.0 and methanol (90:10, v/v), run isocratically at a flow rate of 0.8 mL/min. The size-exclusion method was carried out on a Protein KW 802.5 column (300 mm × 8.0 mm id), at 25°C. The mobile phase consisted of 40 mM sodium acetate solution pH 7.0, run isocratically at a flow rate of 1.0 mL/min. Retention times were 19.3 min, and 14.1 min, and calibration curves were linear over the concentration range of 0.25-250 μg/mL (25.75-25 750 IU/mL) (r 2 = 0.9997) and 5-80 μg/mL (515-8240 IU/mL) (r 2 = 0.9996), respectively, for reversed-phase and size exclusion, with detection at 220 and 204 nm. Chromatographic methods were employed in conjunction with the in vitro bioassay for the content/potency assessment of Streptokinase, contributing to improve the quality control and ensure the efficacy of the biotherapeutic. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Applied in vitro radio bioassay

    International Nuclear Information System (INIS)

    Gaburo, J.C.G.; Sordi, G.M.A.A.

    1992-11-01

    The aim of this publication is to show the concepts and in vitro bioassay techniques as well as experimental procedures related with internal contamination evaluation. The main routes of intake, metabolic behavior, and the possible types of bioassay samples that can be collected for radionuclides analysis are described. Both biological processes and the chemical and physical behavior of the radioactive material of interest are considered and the capabilities of analytical techniques to detect and quantify the radionuclides are discussed. Next, the need of quality assurance throughout procedures are considered and finally a summary of the techniques applied to the internal routine monitoring of IPEN workers is given. (author)

  6. Analysis of microarray leukemia data using an efficient MapReduce-based K-nearest-neighbor classifier.

    Science.gov (United States)

    Kumar, Mukesh; Rath, Nitish Kumar; Rath, Santanu Kumar

    2016-04-01

    Microarray-based gene expression profiling has emerged as an efficient technique for classification, prognosis, diagnosis, and treatment of cancer. Frequent changes in the behavior of this disease generates an enormous volume of data. Microarray data satisfies both the veracity and velocity properties of big data, as it keeps changing with time. Therefore, the analysis of microarray datasets in a small amount of time is essential. They often contain a large amount of expression, but only a fraction of it comprises genes that are significantly expressed. The precise identification of genes of interest that are responsible for causing cancer are imperative in microarray data analysis. Most existing schemes employ a two-phase process such as feature selection/extraction followed by classification. In this paper, various statistical methods (tests) based on MapReduce are proposed for selecting relevant features. After feature selection, a MapReduce-based K-nearest neighbor (mrKNN) classifier is also employed to classify microarray data. These algorithms are successfully implemented in a Hadoop framework. A comparative analysis is done on these MapReduce-based models using microarray datasets of various dimensions. From the obtained results, it is observed that these models consume much less execution time than conventional models in processing big data. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Probabilistic seismic hazard analysis (PSHA) for Ethiopia and the neighboring region

    Science.gov (United States)

    Ayele, Atalay

    2017-10-01

    Seismic hazard calculation is carried out for the Horn of Africa region (0°-20° N and 30°-50°E) based on the probabilistic seismic hazard analysis (PSHA) method. The earthquakes catalogue data obtained from different sources were compiled, homogenized to Mw magnitude scale and declustered to remove the dependent events as required by Poisson earthquake source model. The seismotectonic map of the study area that avails from recent studies is used for area sources zonation. For assessing the seismic hazard, the study area was divided into small grids of size 0.5° × 0.5°, and the hazard parameters were calculated at the center of each of these grid cells by considering contributions from all seismic sources. Peak Ground Acceleration (PGA) corresponding to 10% and 2% probability of exceedance in 50 years were calculated for all the grid points using generic rock site with Vs = 760 m/s. Obtained values vary from 0.0 to 0.18 g and 0.0-0.35 g for 475 and 2475 return periods, respectively. The corresponding contour maps showing the spatial variation of PGA values for the two return periods are presented here. Uniform hazard response spectrum (UHRS) for 10% and 2% probability of exceedance in 50 years and hazard curves for PGA and 0.2 s spectral acceleration (Sa) all at rock site are developed for the city of Addis Ababa. The hazard map of this study corresponding to the 475 return periods has already been used to update and produce the 3rd generation building code of Ethiopia.

  8. Epidemic outbreak of Chikungunya in two neighboring towns in the Colombian Caribbean: a survival analysis.

    Science.gov (United States)

    Oviedo-Pastrana, Misael; Méndez, Nelson; Mattar, Salim; Arrieta, Germán; Gomezcaceres, Luty

    2017-01-01

    The first autochthonous Chikungunya virus transmission in Colombia was reported in September 2014. Three months later, every town in the Caribbean region was affected, including the bordering towns of Ovejas and Corozal, in the department of Sucre. The objective of the study was to analyze and compare the temporal dynamics of the outbreak of Chikungunya in two towns of the department of Sucre. Households with suspicious cases with clinical symptomatology for Chikungunya were enrolled. In each house an epidemiological questionnaire was applied to collect economic and social information and methods for vector control. The study analyzed data collected between 09/01/2014 and 01/31/2015; 458 families in Corozal and 516 families in Ovejas were identified with Chikungunya cases. Estimated attack rates were 10,621 cases and 1640 cases per 100,000 inhabitants, in Ovejas and Corozal, respectively. The 75-day survival curve was 27.2% lower (0.632, CI = 0.614-0.651) in Ovejas than in Corozal (0.904, CI = 0.891-0.917). After 120 days, both curves showed a stable horizontal slope, close to a survival probability of 0.54, indicating the end of the epidemic period. The log-rank test ( X 2  = 94.6, 1fd, p -value = 0.000) showed the improved survival of Chikungunya in the town of Corozal. The relative risk between the two towns was 0.863 (CI = 0.809-0.921; p -value < 0.001). The dynamics of the temporal distribution of CHIKV could be influenced by socioeconomic and preventable risk factors. Poor socioeconomic conditions such as the lack and poor efficiency of water supply and waste collection services could be determining factors in the proliferation of CHIKV. The survival analysis proved to be a suitable method for studying the presentation of CHIKV and can be applied to other prevalent vector-borne diseases such as the ZIKA and Dengue.

  9. In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum

    Directory of Open Access Journals (Sweden)

    Sohail Ahmad

    2016-01-01

    Full Text Available The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm. Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25–225 μg/mL. Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines.

  10. In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum.

    Science.gov (United States)

    Ahmad, Sohail; AbdEl-Salam, Naser M; Ullah, Riaz

    2016-01-01

    The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm). Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25-225 μg/mL). Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines.

  11. Temperature changes between neighboring days and mortality in summer: a distributed lag non-linear time series analysis.

    Directory of Open Access Journals (Sweden)

    Hualiang Lin

    Full Text Available BACKGROUND: Many studies have shown that high temperatures or heat waves were associated with mortality and morbidity. However, few studies have examined whether temperature changes between neighboring days have any significant impact on human health. METHOD: A distributed lag non-linear model was employed to investigate the effect of temperature changes on mortality in summer during 2006-2010 in two subtropical Chinese cities. The temperature change was defined as the difference of the current day's and the previous day's mean temperature. RESULTS: We found non-linear effects of temperature changes between neighboring days in summer on mortality in both cities. Temperature increase was associated with increased mortality from non-accidental diseases and cardiovascular diseases, while temperature decrease had a protective effect on non-accidental mortality and cardiovascular mortality in both cities. Significant association between temperature changes and respiratory mortality was only found in Guangzhou. CONCLUSION: This study suggests that temperature changes between neighboring days might be an alternative temperature indicator for studying temperature-mortality relationship.

  12. Assessing the Impacts of Reduced Noise Operations of Wind Turbines on Neighbor Annoyance: A Preliminary Analysis in Vinalhaven, Maine

    Energy Technology Data Exchange (ETDEWEB)

    Hoen, Ben; Wiser, Ryan; Eckholdt, Haftan

    2010-06-23

    Neighbors living near the 3 turbine, 4.5 MW Vinalhaven, Maine wind power facility, which began operations in late 2009, have complained that the noise from the turbines is unwelcome and annoying. Fox Islands Wind, the owner of the facility, hypothesized that implementing a Noise Reduced Operation (NRO) for the turbines, which effectively limits the turbines maximum rpm and power output, would reduce the sound levels produced by the turbines, and therefore might also reduce the degree to which the neighbors report being annoyed by those sounds. To test this hypothesis in a preliminary fashion, a pilot study was conducted in early 2010, the results of which are the subject of this brief report. The study included asking near-by residents - those within roughly 3000 feet - to rate the sounds and the degree to which they were annoyed by them using logs which they filled out at multiple times during the day on as many days as were possible in the 35 day study period in February and March, 2010. Meanwhile, FIW adjusted the NRO settings of the turbines in a random fashion in the evenings during the same period, but in a pattern that the respondents were not made aware of. Ultimately, nine individuals turned in roughly 200 log entries (i.e., responses), each of which was time coded to allow testing if the response was correlated with the wind facility operating conditions at that time. The analysis of these data found small, non-statistically-significant differences in self-reported turbine loudness and annoyance ratings between the periods when the NRO was enacted and when it was not, after controlling for many of the relationships that could independently influence perceived loudness and annoyance (e.g., wind direction, time of day). Possible explanations for these small differences in self-reported turbine loudness and annoyance ratings include: the relative difference in sound output from the turbines when NRO was engaged and when it was not was small; and/or that

  13. Effect-directed analysis of cold-pressed hemp, flax and canola seed oils by planar chromatography linked with (bio)assays and mass spectrometry.

    Science.gov (United States)

    Teh, Sue-Siang; Morlock, Gertrud E

    2015-11-15

    Cold-pressed hemp, flax and canola seed oils are healthy oils for human consumption as these are rich in polyunsaturated fatty acids and bioactive phytochemicals. However, bioactive information on the food intake side is mainly focused on target analysis. For more comprehensive information with regard to effects, single bioactive compounds present in the seed oil extracts were detected by effect-directed assays, like bioassays or an enzymatic assay, directly linked with chromatography and further characterized by mass spectrometry. This effect-directed analysis is a streamlined method for the analysis of bioactive compounds in the seed oil extracts. All effective compounds with regard to the five assays or bioassays applied were detected in the samples, meaning also bioactive breakdown products caused during oil processing, residues or contaminants, aside the naturally present bioactive phytochemicals. The investigated cold-pressed oils contained compounds that exert antioxidative, antimicrobial, acetylcholinesterase inhibitory and estrogenic activities. This effect-directed analysis can be recommended for bioactivity profiling of food to obtain profound effect-directed information on the food intake side. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Analysis of Bioactive Components of Oilseed Cakes by High-Performance Thin-Layer Chromatography-(Bioassay Combined with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Sue-Siang Teh

    2015-03-01

    Full Text Available Hemp, flax and canola seed cakes are byproducts of the plant oil extraction industry that have not received much attention in terms of their potential use for human food instead of animal feed. Thus, the bioactivity profiling of these oilseed cakes is of interest. For their effect-directed analysis, planar chromatography was combined with several (bioassays, namely 2,2-diphenyl-1-picrylhydrazyl scavenging, acetylcholine esterase inhibition, planar yeast estrogen screen, antimicrobial Bacillus subtilis and Aliivibrio fischeri assays. The streamlined high-performance thin-layer chromatography (HPTLC-bioassay method allowed the discovery of previously unknown bioactive compounds present in these oilseed cake extracts. In contrast to target analysis, the direct link to the effective compounds allowed comprehensive information with regard to selected effects. HPTLC-electrospray ionization-mass spectrometry via the elution-head based TLC-MS Interface was used for a first characterization of the unknown effective compounds. The demonstrated bioactivity profiling on the feed/food intake side may guide the isolation of active compounds for production of functional food or for justified motivation of functional feed/food supplements.

  15. Tradescantia micronucleus bioassay.

    Science.gov (United States)

    Ma, T H; Cabrera, G L; Chen, R; Gill, B S; Sandhu, S S; Vandenberg, A L; Salamone, M F

    1994-10-16

    Four coded chemicals, azidoglycerol (AG), N-methyl-N-nitrosourea (MNU), sodium azide (NaN3), and maleic hydrazide (MH), were tested with the Tradescantia micronucleus (Trad-MCN) bioassay by five independent laboratories from five different countries. The purpose of this international collaborative study was to evaluate four plant bioassays, of which the Trad-MCN assay was one, for their sensitivity, efficiency and reliability. The study was carried out under the sponsorship of the International Programme on Chemical Safety. All laboratories adhered to a standard Trad-MCN protocol which suggested that three replicate tests be conducted with each chemical. The results reported by all laboratories, although not equal, showed good agreement among the laboratories. In fact, all five laboratories obtained positive results with MH and MNU, while four of the five laboratories achieved positive results with NaN3. AG was tested in only three laboratories. Two reported negative results, while one reported positive results but only at a single high dose. The data from this study suggest that under normal conditions, the Trad-MCN bioassay is an efficient and reliable short-term bioassay for clastogens. It is suitable for the rapid screening of chemicals, and also is specially qualified for in situ monitoring of ambient pollutants.

  16. Automated analysis of long-term grooming behavior in Drosophila using a k-nearest neighbors classifier

    Science.gov (United States)

    Allen, Victoria W; Shirasu-Hiza, Mimi

    2018-01-01

    Despite being pervasive, the control of programmed grooming is poorly understood. We addressed this gap by developing a high-throughput platform that allows long-term detection of grooming in Drosophila melanogaster. In our method, a k-nearest neighbors algorithm automatically classifies fly behavior and finds grooming events with over 90% accuracy in diverse genotypes. Our data show that flies spend ~13% of their waking time grooming, driven largely by two major internal programs. One of these programs regulates the timing of grooming and involves the core circadian clock components cycle, clock, and period. The second program regulates the duration of grooming and, while dependent on cycle and clock, appears to be independent of period. This emerging dual control model in which one program controls timing and another controls duration, resembles the two-process regulatory model of sleep. Together, our quantitative approach presents the opportunity for further dissection of mechanisms controlling long-term grooming in Drosophila. PMID:29485401

  17. Integration of Microfractionation, qNMR and Zebrafish Screening for the In Vivo Bioassay-Guided Isolation and Quantitative Bioactivity Analysis of Natural Products

    OpenAIRE

    Bohni, Nadine; Cordero-Maldonado, Mar?a Lorena; Maes, Jan; Siverio-Mota, Dany; Marcourt, Laurence; Munck, Sebastian; Kamuhabwa, Appolinary R.; Moshi, Mainen J.; Esguerra, Camila V.; de Witte, Peter A. M.; Crawford, Alexander D.; Wolfender, Jean-Luc

    2013-01-01

    Natural products (NPs) are an attractive source of chemical diversity for small-molecule drug discovery. Several challenges nevertheless persist with respect to NP discovery, including the time and effort required for bioassay-guided isolation of bioactive NPs, and the limited biomedical relevance to date of in vitro bioassays used in this context. With regard to bioassays, zebrafish have recently emerged as an effective model system for chemical biology, allowing in vivo high-content screens...

  18. Results of bulk sediment analysis and bioassay testing on selected sediments from Oakland Inner Harbor and Alcatraz disposal site, San Francisco, California

    Energy Technology Data Exchange (ETDEWEB)

    Word, J Q; Ward, J A; Woodruff, D L

    1990-09-01

    The Battelle/Marine Sciences Laboratory (MSL) was contracted by the US Army Corps of Engineers, San Francisco District, to perform bulk sediment analysis and oyster larvae bioassays (elutriate) on sediments from Inner Oakland Harbor, California. Analysis of sediment characteristics by MSL indicated elevated priority pollutants, PAHs, pesticides, metals, organotins, and oil and grease concentrations, when compared to Alcatraz Island Dredged Material Disposal Site sediment concentrations. Larvae of the Pacific oyster, Crassostrea gigas, were exposed to seawater collected from the Alcatraz Island Site water, and a series of controls using water and sediments collected from Sequim Bay, Washington. Exposure of larvae to the Alcatraz seawater and the 50% and 100% elutriate concentrations from each Oakland sediment resulted in low survival and a high proportion of abnormal larvae compared to Sequim Bay control exposures. MSL identified that field sample collection, preservation, and storage protocols used by Port of Oakland contractors were inconsistent with standard accepted practices. 23 refs., 10 figs., 40 tabs.

  19. Results of bulk sediment analysis and bioassay testing on selected sediments from Oakland Inner Harbor and Alcatraz disposal site, San Francisco, California

    International Nuclear Information System (INIS)

    Word, J.Q.; Ward, J.A.; Woodruff, D.L.

    1990-09-01

    The Battelle/Marine Sciences Laboratory (MSL) was contracted by the US Army Corps of Engineers, San Francisco District, to perform bulk sediment analysis and oyster larvae bioassays (elutriate) on sediments from Inner Oakland Harbor, California. Analysis of sediment characteristics by MSL indicated elevated priority pollutants, PAHs, pesticides, metals, organotins, and oil and grease concentrations, when compared to Alcatraz Island Dredged Material Disposal Site sediment concentrations. Larvae of the Pacific oyster, Crassostrea gigas, were exposed to seawater collected from the Alcatraz Island Site water, and a series of controls using water and sediments collected from Sequim Bay, Washington. Exposure of larvae to the Alcatraz seawater and the 50% and 100% elutriate concentrations from each Oakland sediment resulted in low survival and a high proportion of abnormal larvae compared to Sequim Bay control exposures. MSL identified that field sample collection, preservation, and storage protocols used by Port of Oakland contractors were inconsistent with standard accepted practices. 23 refs., 10 figs., 40 tabs

  20. A Local Weighted Nearest Neighbor Algorithm and a Weighted and Constrained Least-Squared Method for Mixed Odor Analysis by Electronic Nose Systems

    Directory of Open Access Journals (Sweden)

    Jyuo-Min Shyu

    2010-11-01

    Full Text Available A great deal of work has been done to develop techniques for odor analysis by electronic nose systems. These analyses mostly focus on identifying a particular odor by comparing with a known odor dataset. However, in many situations, it would be more practical if each individual odorant could be determined directly. This paper proposes two methods for such odor components analysis for electronic nose systems. First, a K-nearest neighbor (KNN-based local weighted nearest neighbor (LWNN algorithm is proposed to determine the components of an odor. According to the component analysis, the odor training data is firstly categorized into several groups, each of which is represented by its centroid. The examined odor is then classified as the class of the nearest centroid. The distance between the examined odor and the centroid is calculated based on a weighting scheme, which captures the local structure of each predefined group. To further determine the concentration of each component, odor models are built by regressions. Then, a weighted and constrained least-squares (WCLS method is proposed to estimate the component concentrations. Experiments were carried out to assess the effectiveness of the proposed methods. The LWNN algorithm is able to classify mixed odors with different mixing ratios, while the WCLS method can provide good estimates on component concentrations.

  1. Analysis of the special consequences of the Barij essence industrial complex of Kashan in the development of neighboring rural areas

    Directory of Open Access Journals (Sweden)

    Mohsen Shaterian

    2017-04-01

    Full Text Available In the late decades, the development of industrial activities in the rural areas of Iran have caused some changes in different aspects of these areas which influence the special patterns of rural areas. This article aims to identify the changes that have been the results of industrial development and it’s reflection in the development of rural residential areas. The main intention of this study is to analyze the special consequences (economic, social and anatomical of the industrial center of Kashan in the development of neighboring rural areas. The industrial center consists of three factories that are for making essence, making equipment for gardeners and distillers and the Barij Company. All of the above companies are called the Industrial Center of Barij Essence. It has employed 1050 workers from amongst whom 120 people were identified and the questionnaires were randomly distributed among these workers. To analyze the data based on the measurement variables, descriptive and analytic methods (T were used. The results showed that economically, having rural industries has led to an increase in the people’s intake of  calories, seeing more consumption in long lasting goods and more satisfaction in the native people of the area. In addition, there is more social involvement,  improvements in not wasting the residents’ free time, decreasing of  natives immigration out of the rural areas and finally anatomically, quantity and quality improvement in the rural houses.

  2. Prediction of operon-like gene clusters in the Arabidopsis thaliana genome based on co-expression analysis of neighboring genes.

    Science.gov (United States)

    Wada, Masayoshi; Takahashi, Hiroki; Altaf-Ul-Amin, Md; Nakamura, Kensuke; Hirai, Masami Y; Ohta, Daisaku; Kanaya, Shigehiko

    2012-07-15

    Operon-like arrangements of genes occur in eukaryotes ranging from yeasts and filamentous fungi to nematodes, plants, and mammals. In plants, several examples of operon-like gene clusters involved in metabolic pathways have recently been characterized, e.g. the cyclic hydroxamic acid pathways in maize, the avenacin biosynthesis gene clusters in oat, the thalianol pathway in Arabidopsis thaliana, and the diterpenoid momilactone cluster in rice. Such operon-like gene clusters are defined by their co-regulation or neighboring positions within immediate vicinity of chromosomal regions. A comprehensive analysis of the expression of neighboring genes therefore accounts a crucial step to reveal the complete set of operon-like gene clusters within a genome. Genome-wide prediction of operon-like gene clusters should contribute to functional annotation efforts and provide novel insight into evolutionary aspects acquiring certain biological functions as well. We predicted co-expressed gene clusters by comparing the Pearson correlation coefficient of neighboring genes and randomly selected gene pairs, based on a statistical method that takes false discovery rate (FDR) into consideration for 1469 microarray gene expression datasets of A. thaliana. We estimated that A. thaliana contains 100 operon-like gene clusters in total. We predicted 34 statistically significant gene clusters consisting of 3 to 22 genes each, based on a stringent FDR threshold of 0.1. Functional relationships among genes in individual clusters were estimated by sequence similarity and functional annotation of genes. Duplicated gene pairs (determined based on BLAST with a cutoff of EOperon-like clusters tend to include genes encoding bio-machinery associated with ribosomes, the ubiquitin/proteasome system, secondary metabolic pathways, lipid and fatty-acid metabolism, and the lipid transfer system. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Identifying influential neighbors in animal flocking.

    Science.gov (United States)

    Jiang, Li; Giuggioli, Luca; Perna, Andrea; Escobedo, Ramón; Lecheval, Valentin; Sire, Clément; Han, Zhangang; Theraulaz, Guy

    2017-11-01

    Schools of fish and flocks of birds can move together in synchrony and decide on new directions of movement in a seamless way. This is possible because group members constantly share directional information with their neighbors. Although detecting the directionality of other group members is known to be important to maintain cohesion, it is not clear how many neighbors each individual can simultaneously track and pay attention to, and what the spatial distribution of these influential neighbors is. Here, we address these questions on shoals of Hemigrammus rhodostomus, a species of fish exhibiting strong schooling behavior. We adopt a data-driven analysis technique based on the study of short-term directional correlations to identify which neighbors have the strongest influence over the participation of an individual in a collective U-turn event. We find that fish mainly react to one or two neighbors at a time. Moreover, we find no correlation between the distance rank of a neighbor and its likelihood to be influential. We interpret our results in terms of fish allocating sequential and selective attention to their neighbors.

  4. Identifying influential neighbors in animal flocking.

    Directory of Open Access Journals (Sweden)

    Li Jiang

    2017-11-01

    Full Text Available Schools of fish and flocks of birds can move together in synchrony and decide on new directions of movement in a seamless way. This is possible because group members constantly share directional information with their neighbors. Although detecting the directionality of other group members is known to be important to maintain cohesion, it is not clear how many neighbors each individual can simultaneously track and pay attention to, and what the spatial distribution of these influential neighbors is. Here, we address these questions on shoals of Hemigrammus rhodostomus, a species of fish exhibiting strong schooling behavior. We adopt a data-driven analysis technique based on the study of short-term directional correlations to identify which neighbors have the strongest influence over the participation of an individual in a collective U-turn event. We find that fish mainly react to one or two neighbors at a time. Moreover, we find no correlation between the distance rank of a neighbor and its likelihood to be influential. We interpret our results in terms of fish allocating sequential and selective attention to their neighbors.

  5. A Markov chain Monte Carlo Expectation Maximization Algorithm for Statistical Analysis of DNA Sequence Evolution with Neighbor-Dependent Substitution Rates

    DEFF Research Database (Denmark)

    Hobolth, Asger

    2008-01-01

    -dimensional integrals required in the EM algorithm are estimated using MCMC sampling. The MCMC sampler requires simulation of sample paths from a continuous time Markov process, conditional on the beginning and ending states and the paths of the neighboring sites. An exact path sampling algorithm is developed......The evolution of DNA sequences can be described by discrete state continuous time Markov processes on a phylogenetic tree. We consider neighbor-dependent evolutionary models where the instantaneous rate of substitution at a site depends on the states of the neighboring sites. Neighbor......-dependent substitution models are analytically intractable and must be analyzed using either approximate or simulation-based methods. We describe statistical inference of neighbor-dependent models using a Markov chain Monte Carlo expectation maximization (MCMC-EM) algorithm. In the MCMC-EM algorithm, the high...

  6. Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games.

    Science.gov (United States)

    Gao, Yi; Zhang, Meigen

    2012-01-01

    The regional air quality modeling system RAMS (regional atmospheric modeling system)-CMAQ (community multi-scale air quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008. Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind, temperature and ozone, but NOx concentration is overestimated. Although ozone concentration decreased during Olympics, high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 microg/m3 at Aoyuncun site, respectively. The analysis of sensitive test, with and without emission controls, shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning. The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate. Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August, horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer. On 24 July, as the wind velocity was smaller, the impact of transport on the rural place was not obvious.

  7. Reproductive toxicity assessment of surface water of the Tai section of the Yangtze River, China by in vitro bioassays coupled with chemical analysis

    International Nuclear Information System (INIS)

    Wang Xiaoyi; Wu Jiang; Hao Yingqun; Zhu Bingqing; Shi Wei; Hu Guanjiu; Han Xiaodong; Giesy, John P.; Yu Hongxia

    2011-01-01

    Reproductive toxicity of organic extracts of the surface water from the Tai section of the Yangtze River was assessed by in vitro cytotoxity assays and selected persistent organic pollutants including PCBs, OCPs and PAHs were quantified by instrumental analysis. Eleven of the US EPA priority PAHs were detected. Individual PAHs were found to range from 0.7 to 20 ng/L. Concentrations of BaP did not exceed the national drinking water source quality standard of China. However, a 286-fold concentrated organic extract induced significant reproductive toxicity in adult male rats. The morphology of cells, MTT assay and LDH release assay were all affected by exposure to the organic extracts of water. The results of the reproductive toxicity indicated that PAHs posed the greatest risk of the chemicals studied. The compounds present in the water could be bioconcentrated and result in adverse effects. - Highlights: → Only 11 PAHs of US EPA priority PAHs were detected in surface water the Yangtze River. → Level of BaP didn't exceed national drinking water source quality standard of China. → 286-fold concentrated organic extracts induced great reproductive toxicity in rats. → PAHs posed the greatest risk of the chemicals studied. → The compounds in the water could be bioconcentrated and result in adverse effects. - In vitro bioassay responses observed in Yangtze River source water extracts showed great reproductive toxicity, and PAHs were responsible.

  8. Fluorescence lifetime based bioassays

    Science.gov (United States)

    Meyer-Almes, Franz-Josef

    2017-12-01

    Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.

  9. Integration of Microfractionation, qNMR and zebrafish screening for the in vivo bioassay-guided isolation and quantitative bioactivity analysis of natural products.

    Directory of Open Access Journals (Sweden)

    Nadine Bohni

    Full Text Available Natural products (NPs are an attractive source of chemical diversity for small-molecule drug discovery. Several challenges nevertheless persist with respect to NP discovery, including the time and effort required for bioassay-guided isolation of bioactive NPs, and the limited biomedical relevance to date of in vitro bioassays used in this context. With regard to bioassays, zebrafish have recently emerged as an effective model system for chemical biology, allowing in vivo high-content screens that are compatible with microgram amounts of compound. For the deconvolution of the complex extracts into their individual constituents, recent progress has been achieved on several fronts as analytical techniques now enable the rapid microfractionation of extracts, and microflow NMR methods have developed to the point of allowing the identification of microgram amounts of NPs. Here we combine advanced analytical methods with high-content screening in zebrafish to create an integrated platform for microgram-scale, in vivo NP discovery. We use this platform for the bioassay-guided fractionation of an East African medicinal plant, Rhynchosia viscosa, resulting in the identification of both known and novel isoflavone derivatives with anti-angiogenic and anti-inflammatory activity. Quantitative microflow NMR is used both to determine the structure of bioactive compounds and to quantify them for direct dose-response experiments at the microgram scale. The key advantages of this approach are (1 the microgram scale at which both biological and analytical experiments can be performed, (2 the speed and the rationality of the bioassay-guided fractionation - generic for NP extracts of diverse origin - that requires only limited sample-specific optimization and (3 the use of microflow NMR for quantification, enabling the identification and dose-response experiments with only tens of micrograms of each compound. This study demonstrates that a complete in vivo bioassay

  10. Integration of Microfractionation, qNMR and zebrafish screening for the in vivo bioassay-guided isolation and quantitative bioactivity analysis of natural products.

    Science.gov (United States)

    Bohni, Nadine; Cordero-Maldonado, María Lorena; Maes, Jan; Siverio-Mota, Dany; Marcourt, Laurence; Munck, Sebastian; Kamuhabwa, Appolinary R; Moshi, Mainen J; Esguerra, Camila V; de Witte, Peter A M; Crawford, Alexander D; Wolfender, Jean-Luc

    2013-01-01

    Natural products (NPs) are an attractive source of chemical diversity for small-molecule drug discovery. Several challenges nevertheless persist with respect to NP discovery, including the time and effort required for bioassay-guided isolation of bioactive NPs, and the limited biomedical relevance to date of in vitro bioassays used in this context. With regard to bioassays, zebrafish have recently emerged as an effective model system for chemical biology, allowing in vivo high-content screens that are compatible with microgram amounts of compound. For the deconvolution of the complex extracts into their individual constituents, recent progress has been achieved on several fronts as analytical techniques now enable the rapid microfractionation of extracts, and microflow NMR methods have developed to the point of allowing the identification of microgram amounts of NPs. Here we combine advanced analytical methods with high-content screening in zebrafish to create an integrated platform for microgram-scale, in vivo NP discovery. We use this platform for the bioassay-guided fractionation of an East African medicinal plant, Rhynchosia viscosa, resulting in the identification of both known and novel isoflavone derivatives with anti-angiogenic and anti-inflammatory activity. Quantitative microflow NMR is used both to determine the structure of bioactive compounds and to quantify them for direct dose-response experiments at the microgram scale. The key advantages of this approach are (1) the microgram scale at which both biological and analytical experiments can be performed, (2) the speed and the rationality of the bioassay-guided fractionation - generic for NP extracts of diverse origin - that requires only limited sample-specific optimization and (3) the use of microflow NMR for quantification, enabling the identification and dose-response experiments with only tens of micrograms of each compound. This study demonstrates that a complete in vivo bioassay

  11. Advancing the analysis of low level uranium and plutonium in bioassay samples using SF-ICP-MS

    OpenAIRE

    Burraston, Jade Danielle

    2015-01-01

    The routine monitoring of workers exposed to uranium and plutonium traditionally uses urine samples. Conventionally this analysis, typically using ?1 L urine samples, is carried out by alpha spectrometry. A method for the rapid, simultaneous determination of plutonium and uranium in urine has been developed. It significantly improves on traditional methods by exploiting the increased sensitivity achievable using SF-ICP-MS, and uses much smaller (40 mL) sample volumes. The ultimate aim for det...

  12. Prepared for the thirtieth annual conference on bioassay analytical and environmental chemistry. Reliable analysis of high resolution gamma spectra

    International Nuclear Information System (INIS)

    Spitz, H.B.; Buschbom, R.; Rieksts, G.A.; Palmer, H.E.

    1985-01-01

    A new method has been developed to reliably analyze pulse height-energy spectra obtained from measurements employing high resolution germanium detectors. The method employs a simple data transformation and smoothing function to calculate background and identify photopeaks and isotopic analysis. This technique is elegant in its simplicity because it avoids dependence upon complex spectrum deconvolution, stripping, or other least-square-fitting techniques which complicate the assessment of measurement reliability. A moving median was chosen for data smoothing because, unlike moving averages, medians are not dominated by extreme data points. Finally, peaks are identified whenever the difference between the background spectrum and the transformed spectrum exceeds a pre-determined number of standard deviations

  13. An integrated approach combining chemical analysis and an in vivo bioassay to assess the estrogenic potency of a municipal solid waste landfill leachate in Qingdao.

    Directory of Open Access Journals (Sweden)

    Yufeng Gong

    Full Text Available Various adverse effects related to landfill leachate have made leachates an important issue in past decades, and it has been demonstrated that landfill leachate is an important source of environmental estrogens. In this study, we employed chemical analysis of some already evaluated estrogenic substances, in combination with a bioassay using several specific biomarkers (e.g., plasma vitellogenin and sex steroids, enzyme activity of gonad gamma-glutamyl transpeptidase, and gonadosomatic index to evaluate the estrogenic activities in outlets from different stages of the leachate treatment process. The results indicated that 5 environmental estrogens (4-t-octylphenol, bisphenol A, di-ethyl phthalate, di-n-butyl phthalate, and diethylhexyl phthalate were detected by a gas chromatography-mass spectrometry, and the concentrations in leachate samples were 6153 ng/L, 3642 ng/L, 2139 ng/L, 5900 ng/L, and 9422 ng/L, respectively. Leachate (1∶200 diluted induced the synthesis of plasma vitellogenin and led to decreased enzyme activity of gonad gamma-glutamyl transpeptidase and gonadosomatic index in male goldfish (Carassius auratus after a 28-day exposure, while increased circulating 17β-estradiol level was also observed in males exposed to treated effluent. Although the target EEs were partially removed with removal rates varying from 87.2% to 99.77% by the "membrane bioreactor+reverse osmosis+aeration zeolite biofilter" treatment process, the treated effluent is still estrogenic to fish. The method combined chemical techniques with the responses of test organisms allowing us to identify the group of estrogen-like chemicals so that we were able to evaluate the overall estrogenic effects of a complex mixture, avoiding false negative assessments.

  14. Bioassays for monitoring insecticide resistance.

    Science.gov (United States)

    Miller, Audra L E; Tindall, Kelly; Leonard, B Rogers

    2010-12-30

    Pest resistance to pesticides is an increasing problem because pesticides are an integral part of high-yielding production agriculture. When few products are labeled for an individual pest within a particular crop system, chemical control options are limited. Therefore, the same product(s) are used repeatedly and continual selection pressure is placed on the target pest. There are both financial and environmental costs associated with the development of resistant populations. The cost of pesticide resistance has been estimated at approximately $ 1.5 billion annually in the United States. This paper will describe protocols, currently used to monitor arthropod (specifically insects) populations for the development of resistance. The adult vial test is used to measure the toxicity to contact insecticides and a modification of this test is used for plant-systemic insecticides. In these bioassays, insects are exposed to technical grade insecticide and responses (mortality) recorded at a specific post-exposure interval. The mortality data are subjected to Log Dose probit analysis to generate estimates of a lethal concentration that provides mortality to 50% (LC(50) of the target populations and a series of confidence limits (CL's) as estimates of data variability. When these data are collected for a range of insecticide-susceptible populations, the LC(50) can be used as baseline data for future monitoring purposes. After populations have been exposed to products, the results can be compared to a previously determined LC(50) using the same methodology.

  15. Model-based determination of the influence of textile fabric on bioassay analysis and the effectiveness of a textile slow-release system of DEET in mosquito control.

    Science.gov (United States)

    Malengier, Benny; Goessens, Tineke; Mafo, Flora F; De Vrieze, Mike; Van Langenhove, Lieva; Wanji, Samuel; Lynen, Frederic

    2015-08-01

    Determining the effectiveness of a product in repelling mosquitoes or other flying insects is a difficult task. One approach is to use a bioassay with textile fabric. We investigated the role of the textile substrate in a bioassay with a numerical model, and compared the outcome with known results for DEET. The model was then used to determine the effectiveness of textile slow-release formulations based on coatings, and results were compared with those of a field study in the Cameroon. Slow-release formulations are difficult to evaluate with standard tests, as the compound needs a build-up time not present in these tests. We found excellent correspondence between the model and the known DEET results without matching parameters. Slow-release approaches are deemed possible but have several drawbacks. Modelling can help in identifying optimal use conditions. The field test with a slow-release system performed better than anticipated by the model, with initially more than 90% repellency. DEET-coated textile was considered not to be marketable, however. We advise that bioassays characterise in more detail the type of textile fabric used so as to allow conclusions to be drawn by textile modelling. As regards coated-textile slow-release systems, more research is needed. We nevertheless advise usage mainly at entry points, e.g. as scrims. © 2014 Society of Chemical Industry.

  16. Studies on Erythropoietin Bioassay Method

    International Nuclear Information System (INIS)

    Cho, Kyoung Sam; Ro, Heung Kyu; Lee, Mun Ho

    1975-01-01

    It is the purpose of this paper to design the most preferable method of erythropoietin bioassay in Korea. Bioassay utilizing polycythemic mice are currently in general use for the indirect determination of erythropoietin. Assay animals are usually prepared either by transfusion or by exposure to reduced oxygen tension in specially constructed chamber. We prepared the polycythemic mice by the specially constructed hypobaric chamber. We observed weights and hematocrits of the mice in the hypobaric chamber, then hematocrits and 72 hours 59 Fe red cell uptake ratio of the polycythemic mice induced by hypoxia after removal from the hypobaric chamber. We designed the method of erythropoietin bioassay according to the results obtained by above experiments. Then we measured the 72 hours 59 Fe red cell uptake ratio of the polycythemic mice with normal saline, normal plasma and anemic plasma according to the method we designed. The results are followed:1) The hematocrits of the mice in hypobaric chamber increased to 74% in 11 days. It is preferable to maintain the pressure of the chamber to 400 mmHg for first 4 days then 300 mmHg for last 10 days to reduce the death rate and time consuming in hypobaric chamber. 2) After removal from the hypobaric chamber, the 72 hours 59 Fe red cell uptake ratio decreased rapidly and maintained the lowest level from the fourth day to tenth day. 3) We design the method of erythropoietin bioassay according to the results of above experiment and to the half life of erythropoietin. 4) The Korean product 59 Fe is mixture of 55 Fe and 59 Fe. And the 59 Fe red cell uptake ratio in normal mice was far less with Korean product 59 Fe than with pure 59 Fe of foreign product. So it is desirable to use pure 59 Fe in this method of erythropoietin bioassay. 5) Considering the cost, the technique, the time consuming and the sensitivity it is the most preferable method of erythropoietin bioassay in Korea using hypobaric chamber to induce the polycythemia.

  17. Approximate Nearest Neighbor Queries among Parallel Segments

    DEFF Research Database (Denmark)

    Emiris, Ioannis Z.; Malamatos, Theocharis; Tsigaridas, Elias

    2010-01-01

    We develop a data structure for answering efficiently approximate nearest neighbor queries over a set of parallel segments in three dimensions. We connect this problem to approximate nearest neighbor searching under weight constraints and approximate nearest neighbor searching on historical data...

  18. Protein Neighbors and Proximity Proteomics*

    Science.gov (United States)

    Rees, Johanna S.; Li, Xue-Wen; Perrett, Sarah; Lilley, Kathryn S.; Jackson, Antony P.

    2015-01-01

    Within cells, proteins can co-assemble into functionally integrated and spatially restricted multicomponent complexes. Often, the affinities between individual proteins are relatively weak, and proteins within such clusters may interact only indirectly with many of their other protein neighbors. This makes proteomic characterization difficult using methods such as immunoprecipitation or cross-linking. Recently, several groups have described the use of enzyme-catalyzed proximity labeling reagents that covalently tag the neighbors of a targeted protein with a small molecule such as fluorescein or biotin. The modified proteins can then be isolated by standard pulldown methods and identified by mass spectrometry. Here we will describe the techniques as well as their similarities and differences. We discuss their applications both to study protein assemblies and to provide a new way for characterizing organelle proteomes. We stress the importance of proteomic quantitation and independent target validation in such experiments. Furthermore, we suggest that there are biophysical and cell-biological principles that dictate the appropriateness of enzyme-catalyzed proximity labeling methods to address particular biological questions of interest. PMID:26355100

  19. Maximum likelihood analysis of bioassay data from long-term follow-up of two refractory PuO2 inhalation cases.

    Science.gov (United States)

    Avtandilashvili, Maia; Brey, Richard; James, Anthony C

    2012-07-01

    The U.S. Transuranium and Uranium Registries' tissue donors 0202 and 0407 are the two most highly exposed of the 18 registrants who were involved in the 1965 plutonium fire accident at a defense nuclear facility. Material released during the fire was well characterized as "high fired" refractory plutonium dioxide with 0.32-μm mass median diameter. The extensive bioassay data from long-term follow-up of these two cases were used to evaluate the applicability of the Human Respiratory Tract Model presented by International Commission on Radiological Protection in Publication 66 and its revision proposed by Gregoratto et al. in order to account for the observed long-term retention of insoluble material in the lungs. The maximum likelihood method was used to calculate the point estimates of intake and tissue doses and to examine the effect of different lung clearance, blood absorption, and systemic models on the goodness-of-fit and estimated dose values. With appropriate adjustments, Gregoratto et al. particle transport model coupled with the customized blood absorption parameters yielded a credible fit to the bioassay data for both cases and predicted the Case 0202 liver and skeletal activities measured postmortem. PuO2 particles produced by the plutonium fire are extremely insoluble. About 1% of this material is absorbed from the respiratory tract relatively rapidly, at a rate of about 1 to 2 d (half-time about 8 to 16 h). The remainder (99%) is absorbed extremely slowly, at a rate of about 5 × 10(-6) d (half-time about 400 y). When considering this situation, it appears that doses to other body organs are negligible in comparison to those to tissues of the respiratory tract. About 96% of the total committed weighted dose equivalent is contributed by the lungs. Doses absorbed by these workers' lungs were high: 3.2 Gy to AI and 6.5 Gy to LNTH for Case 0202 (18 y post-intake) and 3.2 Gy to AI and 55.5 Gy to LNTH for Case 0407 (43 y post-intake). This evaluation

  20. Approximate furthest neighbor with application to annulus query

    DEFF Research Database (Denmark)

    Pagh, Rasmus; Silvestri, Francesco; Sivertsen, Johan von Tangen

    2016-01-01

    Much recent work has been devoted to approximate nearest neighbor queries. Motivated by applications in recommender systems, we consider approximate furthest neighbor (AFN) queries and present a simple, fast, and highly practical data structure for answering AFN queries in high-dimensional Euclid......Much recent work has been devoted to approximate nearest neighbor queries. Motivated by applications in recommender systems, we consider approximate furthest neighbor (AFN) queries and present a simple, fast, and highly practical data structure for answering AFN queries in high...... a variation based on a query-independent ordering of the database points; while this does not have the provable approximation factor of the query-dependent data structure, it offers significant improvement in time and space complexity. We give a theoretical analysis and experimental results. As an application...

  1. Environmental monitoring to the sources of atmospheric emission by the Trad-MCN bioassay and analysis of the accumulative potential for uranium and fluoride

    International Nuclear Information System (INIS)

    Machado, Alessandra C.F.E.; Ramos, Monique M.B.; Alves, Edenise S.

    2009-01-01

    The biomonitoring of the atmospheric contamination constitutes important procedure for adoption of environmental control measures. Biological assays have been employed to evaluate genotoxic agents in the atmosphere. The Tradescantia-micronucleus (Trad-MCN) assay has been extensively used in environmental monitoring owing to its efficiency in the detection of chromosomic damages in cytological preparations of easy execution. In this study we tested the viability of use of Trad-MCN with Tradescantia pallida cv. Purpurea for environmental monitoring in the Experimental Center Aramar (CEA), in Ipero - SP and its leaf accumulation capacity. The plants were exposed in situ, in flower-beds or flowerpots, established close to the sources of atmospheric emission. The bioassay was accomplished according to the usual protocol. The micronucleus frequencies were compared using the variance Kruskal-Wallis test. The obtained results indicated that the biomonitoring model adopted was not the ideal for the CEA, considering that the plant suffered the influence of climatic condition. However the plant showed to have accumulative potential for uranium. (author)

  2. Environmental monitoring to the sources of atmospheric emission by the Trad-MCN bioassay and analysis of the accumulative potential for uranium and fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Alessandra C.F.E., E-mail: alessandra@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil). Div. de Monitoracao Ambiental; Ramos, Monique M.B., E-mail: monique@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil). Div. de Analise de Seguranca; Alves, Edenise S., E-mail: ealves@ibot.sp.gov.b [Instituto de Botanica de Sao Paulo, Sao Paulo, SP (Brazil). Secao de Anatomia

    2009-07-01

    The biomonitoring of the atmospheric contamination constitutes important procedure for adoption of environmental control measures. Biological assays have been employed to evaluate genotoxic agents in the atmosphere. The Tradescantia-micronucleus (Trad-MCN) assay has been extensively used in environmental monitoring owing to its efficiency in the detection of chromosomic damages in cytological preparations of easy execution. In this study we tested the viability of use of Trad-MCN with Tradescantia pallida cv. Purpurea for environmental monitoring in the Experimental Center Aramar (CEA), in Ipero - SP and its leaf accumulation capacity. The plants were exposed in situ, in flower-beds or flowerpots, established close to the sources of atmospheric emission. The bioassay was accomplished according to the usual protocol. The micronucleus frequencies were compared using the variance Kruskal-Wallis test. The obtained results indicated that the biomonitoring model adopted was not the ideal for the CEA, considering that the plant suffered the influence of climatic condition. However the plant showed to have accumulative potential for uranium. (author)

  3. Evolving edited k-nearest neighbor classifiers.

    Science.gov (United States)

    Gil-Pita, Roberto; Yao, Xin

    2008-12-01

    The k-nearest neighbor method is a classifier based on the evaluation of the distances to each pattern in the training set. The edited version of this method consists of the application of this classifier with a subset of the complete training set in which some of the training patterns are excluded, in order to reduce the classification error rate. In recent works, genetic algorithms have been successfully applied to determine which patterns must be included in the edited subset. In this paper we propose a novel implementation of a genetic algorithm for designing edited k-nearest neighbor classifiers. It includes the definition of a novel mean square error based fitness function, a novel clustered crossover technique, and the proposal of a fast smart mutation scheme. In order to evaluate the performance of the proposed method, results using the breast cancer database, the diabetes database and the letter recognition database from the UCI machine learning benchmark repository have been included. Both error rate and computational cost have been considered in the analysis. Obtained results show the improvement achieved by the proposed editing method.

  4. Characterization of estrogen and androgen activity of food contact materials by different in vitro bioassays (YES, YAS, ERα and AR CALUX and chromatographic analysis (GC-MS, HPLC-MS.

    Directory of Open Access Journals (Sweden)

    Johannes Mertl

    Full Text Available Endocrine active substances (EAS show structural similarities to natural hormones and are suspected to affect the human endocrine system by inducing hormone dependent effects. Recent studies with in vitro tests suggest that EAS can leach from packaging into food and may therefore pose a risk to human health. Sample migrates from food contact materials were tested for estrogen and androgen agonists and antagonists with different commonly used in vitro tests. Additionally, chemical trace analysis by GC-MS and HPLC-MS was used to identify potential hormone active substances in sample migrates. A GC-MS method to screen migrates for 29 known or potential endocrine active substances was established and validated. Samples were migrated according to EC 10/2011, concentrated by solid phase extraction and tested with estrogen and androgen responsive reporter gene assays based on yeast cells (YES and YAS or human osteoblast cells (ERα and AR CALUX. A high level of agreement between the different bioassays could be observed by screening for estrogen agonists. Four out of 18 samples tested showed an estrogen activity in a similar range in both, YES and ERα CALUX. Two more samples tested positive in ERα CALUX due to the lower limits of detection in this assay. Androgen agonists could not be detected in any of the tested samples, neither with YAS nor with AR CALUX. When testing for antagonists, significant differences between yeast and human cell-based bioassays were noticed. Using YES and YAS many samples showed a strong antagonistic activity which was not observed using human cell-based CALUX assays. By GC-MS, some known or supposed EAS were identified in sample migrates that showed a biological activity in the in vitro tests. However, no firm conclusions about the sources of the observed hormone activity could be obtained from the chemical results.

  5. Soil plate bioassay: an effective method to determine ecotoxicological risks.

    Science.gov (United States)

    Boluda, R; Roca-Pérez, L; Marimón, L

    2011-06-01

    Heavy metals have become one of the most serious anthropogenic stressors for plants and other living organisms. Having efficient and feasible bioassays available to assess the ecotoxicological risks deriving from soil pollution is necessary. This work determines pollution by Cd, Co, Cr, Cu, Ni, Pb, V and Zn in two soils used for growing rice from the Albufera Natural Park in Valencia (Spain). Both were submitted to a different degree of anthropic activity, and their ecotoxicological risk was assessed by four ecotoxicity tests to compare their effectiveness: Microtox test, Zucconi test, pot bioassay (PB) and soil plate bioassay (SPB). The sensitivity of three plant species (barley, cress and lettuce) was also assessed. The results reveal a different degree of effectiveness and level of inhibition in the target organisms' growth depending on the test applied, to such an extent that the one-way analysis of variance showed significant differences only for the plate bioassay results, with considerable inhibition of root and shoot elongation in seedlings. Of the three plant species selected, lettuce was the most sensitive species to toxic effects, followed by cress and barley. Finally, the results also indicate that the SPB is an efficient, simple and economic alternative to other ecotoxicological assays to assess toxicity risks deriving from soil pollution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Establishment of a bioassay for the toxicity evaluation and quality control of Aconitum herbs

    International Nuclear Information System (INIS)

    Qin, Yi; Wang, Jia-bo; Zhao, Yan-ling; Shan, Li-mei; Li, Bao-cai; Fang, Fang; Jin, Cheng; Xiao, Xiao-he

    2012-01-01

    Highlights: ► A new bioassay was optimized to evaluate the toxicity of Aconitum herbs. ► Characterizing total toxicity is its unique advantage over chemical analysis methods. ► The application of this bioassay promotes the safe use of Aconitum herbs in clinic. - Abstract: Currently, no bioassay is available for evaluating the toxicity of Aconitum herbs, which are well known for their lethal cardiotoxicity and neurotoxicity. In this study, we established a bioassay to evaluate the toxicity of Aconitum herbs. Test sample and standard solutions were administered to rats by intravenous infusion to determine their minimum lethal doses (MLD). Toxic potency was calculated by comparing the MLD. The experimental conditions of the method were optimized and standardized to ensure the precision and reliability of the bioassay. The application of the standardized bioassay was then tested by analyzing 18 samples of Aconitum herbs. Additionally, three major toxic alkaloids (aconitine, mesaconitine, and hypaconitine) in Aconitum herbs were analyzed using a liquid chromatographic method, which is the current method of choice for evaluating the toxicity of Aconitum herbs. We found that for all Aconitum herbs, the total toxicity of the extract was greater than the toxicity of the three alkaloids. Therefore, these three alkaloids failed to account for the total toxicity of Aconitum herbs. Compared with individual chemical analysis methods, the chief advantage of the bioassay is that it characterizes the total toxicity of Aconitum herbs. An incorrect toxicity evaluation caused by quantitative analysis of the three alkaloids might be effectively avoided by performing this bioassay. This study revealed that the bioassay is a powerful method for the safety assessment of Aconitum herbs.

  7. Two-generation saccharin bioassays.

    Science.gov (United States)

    Arnold, D L

    1983-04-01

    The controversy regarding the safety of saccharin for human consumption started shortly after its discovery over 100 years ago and has yet to subside appreciably. The consumption of saccharin, particularly in North America, began to escalate when the U.S. Food and Drug Administration set new standards of identity which allowed foods containing artificial sweeteners to be promoted as "nonnutritive" or "noncaloric" sweeteners for use by the general public. In 1969, when cyclamates were banned, at least 10 single-generation feeding studies were undertaken with saccharin to more accurately assess the potential toxicological consequences resulting from the anticipated increase in its consumption. None of these studies resulted in any overt regulatory action. Subsequently, the introduction of the two-generation chronic toxicity/carcinogenicity bioassay added a new tool to the toxicologist's arsenal. Three two-generation studies using saccharin have since been conducted. The results from these studies clearly show that when rats were exposed to diets containing 5 or 7.5% sodium saccharin from the time of conception to death, an increased frequency of urinary bladder cancers was found, predominantly in the males. While some study results suggested that impurities in commercial saccharin or the presence of urinary tract calculi may have been responsible for the observed bladder tumors, it now appears that these possibilities are highly unlikely. The mechanism by which saccharin elicited the bladder tumors using the two-generation experiment has not been ascertained.

  8. Bioassay-based risk assessment of hazardous waste

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, K.C.; Brown, K.W.; He, L.Y. [Texas A and M Univ., College Station, TX (United States)

    1994-12-31

    Microbial bioassays have been used to assess the genotoxic hazard at more than 30 different hazardous waste sites. Environmental samples were extracted with dichloromethane and methanol, and the resulting residue tested using GC/MS analysis as well as the Salmonella Microsomal and E. coli Prophage Induction assays. At a munitions wastewater contaminated site, there was no correlation between mutagenicity in bacteria, and the risk as estimated from chemical analysis data of trinitrotoluene. Samples 202 and 204 from a coal gasification site contained 72 mg/kg and 9 mg/kg benzo(a)pyrene, whereas the mutagenic responses of these samples were 231 net revertants/mg and 902 revertants/mg, respectively. The data suggest that microbial bioassays provide a valuable tool for monitoring the interactions of the components of a complex mixture.

  9. 76 FR 7845 - Good Neighbor Environmental Board

    Science.gov (United States)

    2011-02-11

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9265-9] Good Neighbor Environmental Board AGENCY: Environmental Protection Agency (EPA). ACTION: Request for Nominations to the Good Neighbor Environmental Board. SUMMARY: The U.S. Environmental Protection Agency (EPA) invites nominations from a diverse range of...

  10. 75 FR 8699 - Good Neighbor Environmental Board

    Science.gov (United States)

    2010-02-25

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9117-9] Good Neighbor Environmental Board AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of meeting. SUMMARY: Under the Federal Advisory Committee Act, Public Law 92-463, EPA gives notice of a meeting of the Good Neighbor Environmental Board (Board...

  11. A Colorimetric Bioassay for Perchlorate

    Science.gov (United States)

    Heinnickel, M. L.; Smith, S.; Coates, J. D.

    2007-12-01

    Recognition of perchlorate (ClO4-) as a widespread contaminant across the United States and its potential adverse affects towards human health has motivated the EPA to place ClO4- on its contaminant candidate list for drinking water supplies. While a federal MCL has not yet been set, a recommended public health goal of 1 ppb (μg.L-1) was established by the US EPA in 2002. To date, methods of detection require use of sensitive ion chromatographic equipment that are expensive, time consuming, and require highly trained personnel for use. Our studies are focused on the development of a highly sensitive, simple, and robust colorimetric bioassay based on the primary enzyme involved in microbial ClO4- reduction, the perchlorate reductase (Pcr). A previously published assay used reduced methyl viologen (MV, the dye is reduced with sodium hydrosulfite) as an electron donor to demonstrate Pcr activity. The assay directly correlates the amount of MV oxidized with the amount of ClO4- reduced by assuming a transfer of four electrons. To test this assumption, we compared actual concentrations of MV oxidized to ClO4- reduced in this assay. ClO4- concentrations were determined using a Dionex ICS-500 ion chromatography system, while MV concentrations were determined using a standard curve generated at 578 nm. Comparisons between the two revealed that twelve molecules of MV were oxidized for each molecule of ClO4- reduced. The oxidation of these additional eight MV molecules is explained by the interaction of the dye with chlorite (the product of the Pcr reaction) and other contaminants that could be present in the enzyme prep. This unsettling result indicated this assay would be problematic for the detection of ClO4- in soil, which has many chemicals that could react with MV. To improve upon this assay, we have tried to reduce ClO4- using less reactive dyes and reductants. The reductants ascorbic acid, NADH, and dithiothreitol drive Pcr catalyzed ClO4- reduction, however, they

  12. Spherical stochastic neighbor embedding of hyperspectral data

    CSIR Research Space (South Africa)

    Lunga, D

    2012-07-01

    Full Text Available of spherical coordinates. This allows the use of an Exit probability distribution to discover the nonlinear characteristics that are inherent in hyperspectral data. In addition, the method directly learns the probability distribution over neighboring pixel maps...

  13. BioAssay templates for the semantic web

    Directory of Open Access Journals (Sweden)

    Alex M. Clark

    2016-05-01

    Full Text Available Annotation of bioassay protocols using semantic web vocabulary is a way to make experiment descriptions machine-readable. Protocols are communicated using concise scientific English, which precludes most kinds of analysis by software algorithms. Given the availability of a sufficiently expressive ontology, some or all of the pertinent information can be captured by asserting a series of facts, expressed as semantic web triples (subject, predicate, object. With appropriate annotation, assays can be searched, clustered, tagged and evaluated in a multitude of ways, analogous to other segments of drug discovery informatics. The BioAssay Ontology (BAO has been previously designed for this express purpose, and provides a layered hierarchy of meaningful terms which can be linked to. Currently the biggest challenge is the issue of content creation: scientists cannot be expected to use the BAO effectively without having access to software tools that make it straightforward to use the vocabulary in a canonical way. We have sought to remove this barrier by: (1 defining a BioAssay Template (BAT data model; (2 creating a software tool for experts to create or modify templates to suit their needs; and (3 designing a common assay template (CAT to leverage the most value from the BAO terms. The CAT was carefully assembled by biologists in order to find a balance between the maximum amount of information captured vs. low degrees of freedom in order to keep the user experience as simple as possible. The data format that we use for describing templates and corresponding annotations is the native format of the semantic web (RDF triples, and we demonstrate some of the ways that generated content can be meaningfully queried using the SPARQL language. We have made all of these materials available as open source (http://github.com/cdd/bioassay-template, in order to encourage community input and use within diverse projects, including but not limited to our own

  14. Nearest Neighbor Queries in Road Networks

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Kolar, Jan; Pedersen, Torben Bach

    2003-01-01

    With wireless communications and geo-positioning being widely available, it becomes possible to offer new e-services that provide mobile users with information about other mobile objects. This paper concerns active, ordered k-nearest neighbor queries for query and data objects that are moving in ...... for the nearest neighbor search in the prototype is presented in detail. In addition, the paper reports on results from experiments with the prototype system....

  15. New Rotifer Bioassays for Aquatic Toxicology

    Science.gov (United States)

    1991-07-01

    AD-A258 002 AD NEW ROTIFER BIOASSAYS FOR AQUATIC TOXICOLOGY FINAL REPORT TERRY W. SNELL JULY 15, 1991 Supported by U.S. ARMY MEDICAL RESEARCH AND...Incluce Securiy Cawhca•r• on) New Rotifer Bioassays for Aquatic Toxicology 12. PERSONAL AUTHOR(S) Terry W. Snell 13a. TYPE OF REPORT 113b. riME COVERED...rotifers. I. A test for brackish and marine environments with Brachionus plicatilis. Aquatic Toxicology . 14: 65-80. Snell, T. W. and G. Persoone. 1989

  16. A rapid bioassay for detecting saxitoxins using a Daphnia acute toxicity test

    International Nuclear Information System (INIS)

    Ferrao-Filho, Aloysio da S.; Soares, Maria Carolina S.; Freitas de Magalhaes, Valeria; Azevedo, Sandra M.F.O.

    2010-01-01

    Bioassays using Daphnia pulex and Moina micrura were designed to detect cyanobacterial neurotoxins in raw water samples. Phytoplankton and cyanotoxins from seston were analyzed during 15 months in a eutrophic reservoir. Effective time to immobilize 50% of the exposed individuals (ET 50 ) was adopted as the endpoint. Paralysis of swimming movements was observed between ∼0.5-3 h of exposure to lake water containing toxic cyanobacteria, followed by an almost complete recovery of the swimming activity within 24 h after being placed in control water. The same effects were observed in bioassays with a saxitoxin-producer strain of Cylindrospermopsis raciborskii isolated from the reservoir. Regression analysis showed significant relationships between ET 50 vs. cell density, biomass and saxitoxins content, suggesting that the paralysis of Daphnia in lake water samples was caused by saxitoxins found in C. raciborskii. Daphnia bioassay was found to be a sensitive method for detecting fast-acting neurotoxins in natural samples, with important advantages over mouse bioassays. - A new Daphnia bioassay, as an alternative to the mouse bioassay, is able to detect effects of fast-acting, potent neurotoxins in raw water.

  17. Selective extraction of actinides by calixarenes: application to bioassay analysis; Extraction selective des actinides par les calixarenes: application a l'analyse radiotoxicologique

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, B

    2006-01-15

    In the context of nuclear workers monitoring, the aim of this PhD was to selectively isolate U, Pu, and Am from urine to propose a new analytical procedure to the Medical and Biology Analysis Laboratories. The 1,3,5-OCH{sub 3}-2,4,6-OCH{sub 2}CONHOH-p-tert-butyl-calix[6]arene molecule has been selected as a promising extractant for U, Pu, and Am. Its physico-chemical properties and its affinity for UO{sub 2}{sup 2+} have been studied through two approaches, one theoretical (molecular modelling at DFT level), and one experimental. The extractions of the three actinides by the hydroxamic calix[6]arene were quantitative in liquid-liquid and solid-liquid systems. Their separation has also been shown possible and efficient. After optimization, the proposed procedure should allow the laboratories to carry out the chemical treatment of urine, before the measurement, in one day instead of the three days needed nowadays. (author)

  18. Combining physico-chemical analysis with a Daphnia magna bioassay to evaluate a recycling technology for drinking water treatment plant waste residuals.

    Science.gov (United States)

    Chen, Ting; Xu, Yongpeng; Zhu, Shijun; Cui, Fuyi

    2015-12-01

    Recycling water treatment plant (WTP) waste residuals is considered to be a feasible method to enhance the efficiency of pollutant removal. This study also evaluated the safety and water quality of a pilot-DWTP waste residuals recycling technology by combining physical-chemistry analysis with a Daphnia magna assay. The water samples taken from each treatment step were extracted and concentrated by XAD-2 resin and were then analyzed for immobilization and enzyme activity with D. magna. The measured parameters, such as the dissolve organic carbon (DOC), UV254 and THM formation potential (THMFPs) of the recycling process, did not obviously increase over 15 days of continuous operation and were even lower than typical values from a conventional process. The extract concentration ranged from 0 to 2 Leq/ml as measured on the 7th and 15th days and the immobilization of D. magna exposed to water treated by the recycling process was nearly equivalent to that of the conventional process. Both the superoxide dismutase (SOD) and the catalase (CAT) activity assay indicated that a lower dose of water extract (0.5, 1, 1.5 Leq/ml) could stimulate the enzyme activity of D. magna, whereas a higher dose (2 Leq/ml at the sampling point C3, R3, R4 ) inhibits the activity. Moreover, the SOD and CAT activity of D. magna with DOC and UV254 showed a strong concentration-effect relationship, where the concentration range of DOC and UV254 were 4.1-16.2 mg/L and 0.071-4.382 cm(-1), respectively. The results showed that there was no statistically significant difference (p>0.05) between the conventional and recycling treatment processes and the toxicity of water samples in the recycling process did not increase during the 15-day continuous recycling trial. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. 7 Vascular Hydrophytes for Bioassay.cdr

    African Journals Online (AJOL)

    Administrator

    Hatakeyama S., Fukushima S., Kasai F. and. Shiraishi H. (1994). Assessment of herbicide effects on algal production in the Kokai River. (Japan) using a model stream and Selenastrum bioassay. Ecotoxicology3: 143–156. Kang J-Y. and Goulder R. (1996). Epiphytic bacteria downstream of sewage-works outfalls. Wat. Res.

  20. SCREENING AND BIOASSAY-GUIDED ISOLATION OF ...

    African Journals Online (AJOL)

    DR. AMINU

    2013-06-01

    Jun 1, 2013 ... from the leaves and stem-root of the plant were sequentially extracted with petroleum ether, chloroform, ethyl acetate and ... Keywords: Bioassay-guided isolation, antimicrobial activity, Laggera mollis, clinical isolates, extracts. INTRODUCTION ... technology (Das et al., 2009). The powdered leaf/stem-root ...

  1. A specific bioassay for the inhibition of flowering.

    Science.gov (United States)

    Blake, J

    1972-06-01

    A bioassay for the inhibition of flowering involving the in vitro culture of excised, partially-induced, apices of Viscaria candida is described. This bioassay has been used to detect flowering inhibition in extracts from Kalanchoe blossfeldiana.

  2. The clinic as a good corporate neighbor.

    Science.gov (United States)

    Sass, Hans-Martin

    2013-02-01

    Clinics today specialize in health repair services similar to car repair shops; procedures and prices are standardized, regulated, and inflexibly uniform. Clinics of the future have to become Health Care Centers in order to be more respected and more effective corporate neighbors in offering outreach services in health education and preventive health care. The traditional concept of care for health is much broader than repair management and includes the promotion of lay health competence and responsibility in healthy social and natural environments. The corporate profile and ethics of the clinic as a good and competitive local neighbor will have to focus on [a] better personalized care, [b] education and services in preventive care, [c] direct or web-based information and advice for general, seasonal, or age related health risks, and on developing and improving trustworthy character traits of the clinic as a corporate person and a good neighbor.

  3. Recrafting the Neighbor-Joining Method

    DEFF Research Database (Denmark)

    Mailund; Brodal, Gerth Stølting; Fagerberg, Rolf

    2006-01-01

    Background: The neighbor-joining method by Saitou and Nei is a widely used method for constructing phylogenetic trees. The formulation of the method gives rise to a canonical Θ(n3) algorithm upon which all existing implementations are based. Methods: In this paper we present techniques for speeding...... up the canonical neighbor-joining method. Our algorithms construct the same phylogenetic trees as the canonical neighbor-joining method. The best-case running time of our algorithms are O(n2) but the worst-case remains O(n3). We empirically evaluate the performance of our algoritms on distance...... matrices obtained from the Pfam collection of alignments. Results: The experiments indicate that the running time of our algorithms evolve as Θ(n2) on the examined instance collection. We also compare the running time with that of the QuickTree tool, a widely used efficient implementation of the canonical...

  4. Brine Shrimp Bioassays: A Useful Technique in Biological Investigations

    Science.gov (United States)

    Rice, Stanley A.; Maness, Ian B.

    2004-01-01

    A technique to measure the potency of leaf compounds against herbivores with the use of a bioassay is described. Bioassays are useful in classes where students have career plans like medicine in which bioassays can be used as tools for screening plants for possible medicinal potency.

  5. Lectures on the nearest neighbor method

    CERN Document Server

    Biau, Gérard

    2015-01-01

    This text presents a wide-ranging and rigorous overview of nearest neighbor methods, one of the most important paradigms in machine learning. Now in one self-contained volume, this book systematically covers key statistical, probabilistic, combinatorial and geometric ideas for understanding, analyzing and developing nearest neighbor methods. Gérard Biau is a professor at Université Pierre et Marie Curie (Paris). Luc Devroye is a professor at the School of Computer Science at McGill University (Montreal).   .

  6. Interpretation of bioassay data from nuclear fuel fabrication workers

    International Nuclear Information System (INIS)

    Melo, D.; Xavier, M.

    2005-01-01

    Full text: In nuclear fuel fabrication facilities, workers are exposed to different compounds of enriched uranium. Although in this kind of facility the main route of intake is inhalation, ingestion may occur in some situations. The interpretation of the bioassay data is very complex, since it is necessary taking into account all the different parameters, which is a big challenge. Due to the high cost of the individual monitoring programme for internal dose assessment in the routine monitoring programmes, usually only one type of measurement is assigned. In complex situations like the one described in this paper, where several parameters can compromise the accuracy of the bioassay interpretation it is need to have a combination of techniques to evaluate the internal dose. According to ICRP 78 (1997), the general order of preference in terms of accuracy of interpretation is: body activity measurement, excreta analysis and personal air sampling. Results of monitoring of working environment may provide information that assists in interpretation on particle size, chemical form and solubility, time of intake. A group of seventeen workers from controlled area of the fuel fabrication facility was selected to evaluate the internal dose using all different available techniques during a certain period. The workers were monitored for determination of uranium content in the daily urinary and faecal excretion (collected over a period of 3 consecutive days), chest counting and personal air sampling. The results have shown that at least two types of sensitivity techniques must be used, since there are some sources of uncertainties on the bioassay interpretation, like mixture of uranium compounds intake and different routes of intake. The combination of urine and faeces analysis has shown to be the more appropriate methodology for assessing internal dose in this situation. (author)

  7. Recrafting the neighbor-joining method

    Directory of Open Access Journals (Sweden)

    Pedersen Christian NS

    2006-01-01

    Full Text Available Abstract Background The neighbor-joining method by Saitou and Nei is a widely used method for constructing phylogenetic trees. The formulation of the method gives rise to a canonical Θ(n3 algorithm upon which all existing implementations are based. Results In this paper we present techniques for speeding up the canonical neighbor-joining method. Our algorithms construct the same phylogenetic trees as the canonical neighbor-joining method. The best-case running time of our algorithms are O(n2 but the worst-case remains O(n3. We empirically evaluate the performance of our algoritms on distance matrices obtained from the Pfam collection of alignments. The experiments indicate that the running time of our algorithms evolve as Θ(n2 on the examined instance collection. We also compare the running time with that of the QuickTree tool, a widely used efficient implementation of the canonical neighbor-joining method. Conclusion The experiments show that our algorithms also yield a significant speed-up, already for medium sized instances.

  8. Nearest Neighbor Search in the Metric Space of a Complex Network for Community Detection

    Directory of Open Access Journals (Sweden)

    Suman Saha

    2016-03-01

    Full Text Available The objective of this article is to bridge the gap between two important research directions: (1 nearest neighbor search, which is a fundamental computational tool for large data analysis; and (2 complex network analysis, which deals with large real graphs but is generally studied via graph theoretic analysis or spectral analysis. In this article, we have studied the nearest neighbor search problem in a complex network by the development of a suitable notion of nearness. The computation of efficient nearest neighbor search among the nodes of a complex network using the metric tree and locality sensitive hashing (LSH are also studied and experimented. For evaluation of the proposed nearest neighbor search in a complex network, we applied it to a network community detection problem. Experiments are performed to verify the usefulness of nearness measures for the complex networks, the role of metric tree and LSH to compute fast and approximate node nearness and the the efficiency of community detection using nearest neighbor search. We observed that nearest neighbor between network nodes is a very efficient tool to explore better the community structure of the real networks. Several efficient approximation schemes are very useful for large networks, which hardly made any degradation of results, whereas they save lot of computational times, and nearest neighbor based community detection approach is very competitive in terms of efficiency and time.

  9. Dimensionality reduction by supervised neighbor embedding using laplacian search.

    Science.gov (United States)

    Zheng, Jianwei; Zhang, Hangke; Cattani, Carlo; Wang, Wanliang

    2014-01-01

    Dimensionality reduction is an important issue for numerous applications including biomedical images analysis and living system analysis. Neighbor embedding, those representing the global and local structure as well as dealing with multiple manifolds, such as the elastic embedding techniques, can go beyond traditional dimensionality reduction methods and find better optima. Nevertheless, existing neighbor embedding algorithms can not be directly applied in classification as suffering from several problems: (1) high computational complexity, (2) nonparametric mappings, and (3) lack of class labels information. We propose a supervised neighbor embedding called discriminative elastic embedding (DEE) which integrates linear projection matrix and class labels into the final objective function. In addition, we present the Laplacian search direction for fast convergence. DEE is evaluated in three aspects: embedding visualization, training efficiency, and classification performance. Experimental results on several benchmark databases present that the proposed DEE exhibits a supervised dimensionality reduction approach which not only has strong pattern revealing capability, but also brings computational advantages over standard gradient based methods.

  10. Dimensionality Reduction by Supervised Neighbor Embedding Using Laplacian Search

    Directory of Open Access Journals (Sweden)

    Jianwei Zheng

    2014-01-01

    Full Text Available Dimensionality reduction is an important issue for numerous applications including biomedical images analysis and living system analysis. Neighbor embedding, those representing the global and local structure as well as dealing with multiple manifolds, such as the elastic embedding techniques, can go beyond traditional dimensionality reduction methods and find better optima. Nevertheless, existing neighbor embedding algorithms can not be directly applied in classification as suffering from several problems: (1 high computational complexity, (2 nonparametric mappings, and (3 lack of class labels information. We propose a supervised neighbor embedding called discriminative elastic embedding (DEE which integrates linear projection matrix and class labels into the final objective function. In addition, we present the Laplacian search direction for fast convergence. DEE is evaluated in three aspects: embedding visualization, training efficiency, and classification performance. Experimental results on several benchmark databases present that the proposed DEE exhibits a supervised dimensionality reduction approach which not only has strong pattern revealing capability, but also brings computational advantages over standard gradient based methods.

  11. Nearest Neighbor Networks: clustering expression data based on gene neighborhoods

    Directory of Open Access Journals (Sweden)

    Olszewski Kellen L

    2007-07-01

    Full Text Available Abstract Background The availability of microarrays measuring thousands of genes simultaneously across hundreds of biological conditions represents an opportunity to understand both individual biological pathways and the integrated workings of the cell. However, translating this amount of data into biological insight remains a daunting task. An important initial step in the analysis of microarray data is clustering of genes with similar behavior. A number of classical techniques are commonly used to perform this task, particularly hierarchical and K-means clustering, and many novel approaches have been suggested recently. While these approaches are useful, they are not without drawbacks; these methods can find clusters in purely random data, and even clusters enriched for biological functions can be skewed towards a small number of processes (e.g. ribosomes. Results We developed Nearest Neighbor Networks (NNN, a graph-based algorithm to generate clusters of genes with similar expression profiles. This method produces clusters based on overlapping cliques within an interaction network generated from mutual nearest neighborhoods. This focus on nearest neighbors rather than on absolute distance measures allows us to capture clusters with high connectivity even when they are spatially separated, and requiring mutual nearest neighbors allows genes with no sufficiently similar partners to remain unclustered. We compared the clusters generated by NNN with those generated by eight other clustering methods. NNN was particularly successful at generating functionally coherent clusters with high precision, and these clusters generally represented a much broader selection of biological processes than those recovered by other methods. Conclusion The Nearest Neighbor Networks algorithm is a valuable clustering method that effectively groups genes that are likely to be functionally related. It is particularly attractive due to its simplicity, its success in the

  12. The nearest neighbor and next nearest neighbor effects on the thermodynamic and kinetic properties of RNA base pair

    Science.gov (United States)

    Wang, Yujie; Wang, Zhen; Wang, Yanli; Liu, Taigang; Zhang, Wenbing

    2018-01-01

    The thermodynamic and kinetic parameters of an RNA base pair with different nearest and next nearest neighbors were obtained through long-time molecular dynamics simulation of the opening-closing switch process of the base pair near its melting temperature. The results indicate that thermodynamic parameters of GC base pair are dependent on the nearest neighbor base pair, and the next nearest neighbor base pair has little effect, which validated the nearest-neighbor model. The closing and opening rates of the GC base pair also showed nearest neighbor dependences. At certain temperature, the closing and opening rates of the GC pair with nearest neighbor AU is larger than that with the nearest neighbor GC, and the next nearest neighbor plays little role. The free energy landscape of the GC base pair with the nearest neighbor GC is rougher than that with nearest neighbor AU.

  13. Dimensionality reduction with unsupervised nearest neighbors

    CERN Document Server

    Kramer, Oliver

    2013-01-01

    This book is devoted to a novel approach for dimensionality reduction based on the famous nearest neighbor method that is a powerful classification and regression approach. It starts with an introduction to machine learning concepts and a real-world application from the energy domain. Then, unsupervised nearest neighbors (UNN) is introduced as efficient iterative method for dimensionality reduction. Various UNN models are developed step by step, reaching from a simple iterative strategy for discrete latent spaces to a stochastic kernel-based algorithm for learning submanifolds with independent parameterizations. Extensions that allow the embedding of incomplete and noisy patterns are introduced. Various optimization approaches are compared, from evolutionary to swarm-based heuristics. Experimental comparisons to related methodologies taking into account artificial test data sets and also real-world data demonstrate the behavior of UNN in practical scenarios. The book contains numerous color figures to illustr...

  14. Nearest Neighbor Algorithms for Pattern Classification

    Science.gov (United States)

    Barrios, J. O.

    1972-01-01

    A solution of the discrimination problem is considered by means of the minimum distance classifier, commonly referred to as the nearest neighbor (NN) rule. The NN rule is nonparametric, or distribution free, in the sense that it does not depend on any assumptions about the underlying statistics for its application. The k-NN rule is a procedure that assigns an observation vector z to a category F if most of the k nearby observations x sub i are elements of F. The condensed nearest neighbor (CNN) rule may be used to reduce the size of the training set required categorize The Bayes risk serves merely as a reference-the limit of excellence beyond which it is not possible to go. The NN rule is bounded below by the Bayes risk and above by twice the Bayes risk.

  15. Network geometry inference using common neighbors

    Science.gov (United States)

    Papadopoulos, Fragkiskos; Aldecoa, Rodrigo; Krioukov, Dmitri

    2015-08-01

    We introduce and explore a method for inferring hidden geometric coordinates of nodes in complex networks based on the number of common neighbors between the nodes. We compare this approach to the HyperMap method, which is based only on the connections (and disconnections) between the nodes, i.e., on the links that the nodes have (or do not have). We find that for high degree nodes, the common-neighbors approach yields a more accurate inference than the link-based method, unless heuristic periodic adjustments (or "correction steps") are used in the latter. The common-neighbors approach is computationally intensive, requiring O (t4) running time to map a network of t nodes, versus O (t3) in the link-based method. But we also develop a hybrid method with O (t3) running time, which combines the common-neighbors and link-based approaches, and we explore a heuristic that reduces its running time further to O (t2) , without significant reduction in the mapping accuracy. We apply this method to the autonomous systems (ASs) Internet, and we reveal how soft communities of ASs evolve over time in the similarity space. We further demonstrate the method's predictive power by forecasting future links between ASs. Taken altogether, our results advance our understanding of how to efficiently and accurately map real networks to their latent geometric spaces, which is an important necessary step toward understanding the laws that govern the dynamics of nodes in these spaces, and the fine-grained dynamics of network connections.

  16. Neighbor Rupture Degree of Some Middle Graphs

    Directory of Open Access Journals (Sweden)

    Gökşen BACAK-TURAN

    2017-12-01

    Full Text Available Networks have an important place in our daily lives. Internet networks, electricity networks, water networks, transportation networks, social networks and biological networks are some of the networks we run into every aspects of our lives. A network consists of centers connected by links. A network is represented when centers and connections modelled by vertices and edges, respectively. In consequence of the failure of some centers or connection lines, measurement of the resistance of the network until the communication interrupted is called vulnerability of the network. In this study, neighbor rupture degree which is a parameter that explores the vulnerability values of the resulting graphs due to the failure of some centers of a communication network and its neighboring centers becoming nonfunctional were applied to some middle graphs and neighbor rupture degree of the $M(C_{n},$ $M(P_{n},$ $M(K_{1,n},$ $M(W_{n},$ $M(P_{n}\\times K_{2}$ and $M(C_{n}\\times K_{2}$ have been found.

  17. Research on Parallelization of GPU-based K-Nearest Neighbor Algorithm

    Science.gov (United States)

    Jiang, Hao; Wu, Yulin

    2017-10-01

    Based on the analysis of the K-Nearest Neighbor Algorithm, the feasibility of parallelization is studied from the steps of the algorithm, the operation efficiency and the data structure of each step, and the part of parallel execution is determined. A K-Nearest Neighbor Algorithm parallelization scheme is designed and the parallel G-KNN algorithm is implemented in the CUDA environment. The experimental results show that the K-Nearest Neighbor Algorithm has a significant improvement in efficiency after parallelization, especially on large-scale data.

  18. Toxicological profiling of sediments with in vitro mechanisms-based bioassays for endocrine disruption

    NARCIS (Netherlands)

    Houtman, C.J.; Cenijn, P.H.; Hamers, T.; Lamoree, M.H.; Legler, J.; Murk, A.J.; Brouwer, A.

    2004-01-01

    In vitro bioassays are valuable tools for screening environmental samples for the presence of bioactive (e.g., endocrine-disrupting) compounds. They can be used to direct chemical analysis of active compounds in toxicity identification and evaluation (TIE) approaches. In the present study, five in

  19. Toxicological profiling of sediments using in vitro bioassays, with emphasis on endocrine disruption

    NARCIS (Netherlands)

    Houtman, C.J.; Cenijn, P.H.; Hamers, T.; Lamoree, M.H.; Legler, J.; Murk, A.J.; Brouwer, A.

    2004-01-01

    In vitro bioassays are valuable tools for screening environmental samples for the presence of bioactive (e.g., endocrine-disrupting) compounds. They can be used to direct chemical analysis of active compounds in toxicity identification and evaluation (TIE) approaches. In the present study, five in

  20. ACTION RECOGNITION USING SALIENT NEIGHBORING HISTOGRAMS

    DEFF Research Database (Denmark)

    Ren, Huamin; Moeslund, Thomas B.

    2013-01-01

    Combining spatio-temporal interest points with Bag-of-Words models achieves state-of-the-art performance in action recognition. However, existing methods based on “bag-ofwords” models either are too local to capture the variance in space/time or fail to solve the ambiguity problem in spatial...... and temporal dimensions. Instead, we propose a salient vocabulary construction algorithm to select visual words from a global point of view, and form compact descriptors to represent discriminative histograms in the neighborhoods. Those salient neighboring histograms are then trained to model different actions...

  1. Primary characteristic marriage in the neighbor countries

    Directory of Open Access Journals (Sweden)

    Ivkov Anđelija

    2005-01-01

    Full Text Available There is a number of data referring to the process of marriage and divorce witch show the marital situation region and also compare it with the situations in other regions or abroad. Apart from the average age of first marriage, we have also analyzable the rate of marriages and divorces, we compared our results with the data referring to Serbia, in the Republic of Srpska and some of the former republics of SFRY (Croatia, Slovenia Federation of Bosnia and Herzegovina and neighbors Bulgaria, Romania Greece.

  2. Approximation result toward nearest neighbor heuristic

    Directory of Open Access Journals (Sweden)

    Monnot Jér"me

    2002-01-01

    Full Text Available In this paper, we revisit the famous heuristic called nearest neighbor (N N for the traveling salesman problem under maximization and minimization goal. We deal with variants where the edge costs belong to interval Ša;taĆ for a>0 and t>1, which certainly corresponds to practical cases of these problems. We prove that NN is a (t+1/2t-approximation for maxTSPŠa;taĆ and a 2/(t+1-approximation for minTSPŠa;taĆ under the standard performance ratio. Moreover, we show that these ratios are tight for some instances.

  3. Model of directed lines for square ice with second-neighbor and third-neighbor interactions

    Science.gov (United States)

    Kirov, Mikhail V.

    2018-02-01

    The investigation of the properties of nanoconfined systems is one of the most rapidly developing scientific fields. Recently it has been established that water monolayer between two graphene sheets forms square ice. Because of the energetic disadvantage, in the structure of the square ice there are no longitudinally arranged molecules. The result is that the structure is formed by unidirectional straight-lines of hydrogen bonds only. A simple but accurate discrete model of square ice with second-neighbor and third-neighbor interactions is proposed. According to this model, the ground state includes all configurations which do not contain three neighboring unidirectional chains of hydrogen bonds. Each triplet increases the energy by the same value. This new model differs from an analogous model with long-range interactions where in the ground state all neighboring chains are antiparallel. The new model is suitable for the corresponding system of point electric (and magnetic) dipoles on the square lattice. It allows separately estimating the different contributions to the total binding energy and helps to understand the properties of infinite monolayers and finite nanostructures. Calculations of the binding energy for square ice and for point dipole system are performed using the packages TINKER and LAMMPS.

  4. The effectiveness of a mediation program in symmetrical versus asymmetrical neighbor-to-neighbor conflicts

    NARCIS (Netherlands)

    Ufkes, Elze G.; Giebels, Ellen; Otten, Sabine; van der Zee, Karen I.

    2012-01-01

    Purpose - The last decades, neighborhood mediation programs have become an increasingly popular method to deal with conflicts between neighbors. In the current paper the aim is to propose and show that conflict asymmetry, the degree to which parties differ in perceptions of the level of conflict,

  5. Applications of bioassay for fission and activation products - Sept. 1980

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This guide identifies the bases that will be used by the NRC staff in evaluating the need for license provisions to require bioassay programs in installations where employees may be subject to internal radiation exposure from the inhalation or ingestion of fission or neutron activation products. It also describes methods acceptable to the NRC staff for determining the persons to be included in a bioassay program, the sampling and measurement techniques to be used, the frequency of bioassay measurements to be made, actions to be taken based on designated levels of internal radioactivity, estimations of internal dose to be calculated from bioassay measurements, and record systems to be maintained appropriate to such bioassay programs

  6. Giant Planets: Good Neighbors for Habitable Worlds?

    Science.gov (United States)

    Georgakarakos, Nikolaos; Eggl, Siegfried; Dobbs-Dixon, Ian

    2018-04-01

    The presence of giant planets influences potentially habitable worlds in numerous ways. Massive celestial neighbors can facilitate the formation of planetary cores and modify the influx of asteroids and comets toward Earth analogs later on. Furthermore, giant planets can indirectly change the climate of terrestrial worlds by gravitationally altering their orbits. Investigating 147 well-characterized exoplanetary systems known to date that host a main-sequence star and a giant planet, we show that the presence of “giant neighbors” can reduce a terrestrial planet’s chances to remain habitable, even if both planets have stable orbits. In a small fraction of systems, however, giant planets slightly increase the extent of habitable zones provided that the terrestrial world has a high climate inertia. In providing constraints on where giant planets cease to affect the habitable zone size in a detrimental fashion, we identify prime targets in the search for habitable worlds.

  7. Co-Expression of Neighboring Genes in the Zebrafish (Danio rerio Genome

    Directory of Open Access Journals (Sweden)

    Daryi Wang

    2009-08-01

    Full Text Available Neighboring genes in the eukaryotic genome have a tendency to express concurrently, and the proximity of two adjacent genes is often considered a possible explanation for their co-expression behavior. However, the actual contribution of the physical distance between two genes to their co-expression behavior has yet to be defined. To further investigate this issue, we studied the co-expression of neighboring genes in zebrafish, which has a compact genome and has experienced a whole genome duplication event. Our analysis shows that the proportion of highly co-expressed neighboring pairs (Pearson’s correlation coefficient R>0.7 is low (0.24% ~ 0.67%; however, it is still significantly higher than that of random pairs. In particular, the statistical result implies that the co-expression tendency of neighboring pairs is negatively correlated with their physical distance. Our findings therefore suggest that physical distance may play an important role in the co-expression of neighboring genes. Possible mechanisms related to the neighboring genes’ co-expression are also discussed.

  8. Worldwide bioassay data resources for plutonium/americium internal dosimetry studies

    International Nuclear Information System (INIS)

    Miller, G.; Bertelli, L.; Little, T.; Guilmette, R.; Riddell, T.; Filipy, R.

    2005-01-01

    Full text: Biokinetic models are the scientific underpinning of internal dosimetry. These models describe how materials of interest taken into the body by various routes (for example inhalation) are transported through the body, allowing the modelling of bioassay measurements and the estimation of radiation dose. The International Commission on Radiation Protection (ICRP) publishes biokinetic models for use in internal dosimetry. These models represent the consensus judgement of a committee of experts, based on human and animal data. Nonetheless, it is important to validate biokinetic models using directly applicable data, in a scientifically transparent manner, especially for internal dosimetry research purposes (as opposed to radiation protection), as in epidemiology studies. Two major goals would be to determine individual variations of model parameters for the purpose of assessing this source of uncertainty in internal dose calculations, and to determine values of workplace specific parameters (such as particle solubility in lung fluids) for different representative workplaces. Furthermore, data on the observed frequency of intakes under various conditions can be used in the interpretation of bioassay data. All of the above may be couched in the terminology of Bayesian statistical analysis and amount to the determination of the Bayesian prior probability distributions needed in a Bayesian interpretation of bioassay data. The authors have direct knowledge of several significant databases of plutonium/americium bioassay data (including autopsy data). The purpose of this paper is to acquaint the worldwide community with these resources and to invite others who may know of other such databases to participate with us in a publication that would document the content, form, and the procedures for seeking access to these databases. These databases represent a tremendous scientific resource in this field. Examples of databases known to the authors include: the

  9. Bioassays for the determination of nitrification inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Grunditz, Camilla

    1999-07-01

    Requirements for nitrogen reduction in wastewater treatment plants were introduced in Sweden in the early 1990's. This was a governmental move to reduce the nitrogen discharges to the Baltic and Kattegat in order to prevent eutrophication. The nitrification process in wastewater treatment plants is performed by nitrifying bacteria. These are susceptible to inhibition and it is of great importance that the influent water does not contain toxic compounds. Therefore, there is a need for assays for the determination of nitrification inhibition. This thesis describes the development and applications of such bioassays. Pure cultures of Nitrosomonas sp. and Nitrobacter sp. were isolated from activated sludge of a wastewater treatment plant. These cultures were used as test organisms in the development of bioassays for nitrification inhibition measurements. The assays are based on two different principles; cell suspensions of the bacteria, performed in test tubes, and mediated amperometric biosensors with the bacteria immobilised. Ammonia oxidation and nitrite oxidation are studied separately without interference from other organisms, which makes it easier to interpret the results. The cell suspension assays were applied to samples of industrial and municipal wastewater. The Nitrosomonas and Nitrobacter assays showed to have different inhibition patterns. A large percentage of the Swedish municipal wastewater treatment plants were found to receive inhibitory influent water, but the inhibition level was generally low. Compared to an assay based on activated sludge, the screening method, the pure culture assays found more samples of influent water strongly inhibitory or stimulating. The highest correlation was found between the screening method and the Nitrosomonas assay. The Nitrobacter assay was found to be the most sensitive method. Assessment of toxicity of a number of chemical substances was studied using the biosensors, together with the cell suspension assays

  10. The control of invasive species on private property with neighbor-to-neighbor spillovers.

    Science.gov (United States)

    Fenichel, Eli P; Richards, Timothy J; Shanafelt, David W

    2014-10-01

    Invasive pests cross property boundaries. Property managers may have private incentives to control invasive species despite not having sufficient incentive to fully internalize the external costs of their role in spreading the invasion. Each property manager has a right to future use of his own property, but his property may abut others' properties enabling spread of an invasive species. The incentives for a foresighted property manager to control invasive species have received little attention. We consider the efforts of a foresighted property manager who has rights to future use of a property and has the ability to engage in repeated, discrete control activities. We find that higher rates of dispersal, associated with proximity to neighboring properties, reduce the private incentives for control. Controlling species at one location provides incentives to control at a neighboring location. Control at neighboring locations are strategic complements and coupled with spatial heterogeneity lead to a weaker-link public good problem, in which each property owner is unable to fully appropriate the benefits of his own control activity. Future-use rights and private costs suggest that there is scope for a series of Coase-like exchanges to internalize much of the costs associated with species invasion. Pigouvian taxes on invasive species potentially have qualitatively perverse behavioral effects. A tax with a strong income effect (e.g, failure of effective revenue recycling) can reduce the value of property assets and diminish the incentive to manage insects on one's own property.

  11. Annotating Human P-Glycoprotein Bioassay Data.

    Science.gov (United States)

    Zdrazil, Barbara; Pinto, Marta; Vasanthanathan, Poongavanam; Williams, Antony J; Balderud, Linda Zander; Engkvist, Ola; Chichester, Christine; Hersey, Anne; Overington, John P; Ecker, Gerhard F

    2012-08-01

    Huge amounts of small compound bioactivity data have been entering the public domain as a consequence of open innovation initiatives. It is now the time to carefully analyse existing bioassay data and give it a systematic structure. Our study aims to annotate prominent in vitro assays used for the determination of bioactivities of human P-glycoprotein inhibitors and substrates as they are represented in the ChEMBL and TP-search open source databases. Furthermore, the ability of data, determined in different assays, to be combined with each other is explored. As a result of this study, it is suggested that for inhibitors of human P-glycoprotein it is possible to combine data coming from the same assay type, if the cell lines used are also identical and the fluorescent or radiolabeled substrate have overlapping binding sites. In addition, it demonstrates that there is a need for larger chemical diverse datasets that have been measured in a panel of different assays. This would certainly alleviate the search for other inter-correlations between bioactivity data yielded by different assay setups.

  12. Text Categorization Using Weight Adjusted k-Nearest Neighbor Classification

    National Research Council Canada - National Science Library

    Han, Euihong; Karypis, George; Kumar, Vipin

    1999-01-01

    .... The authors present a nearest neighbor classification scheme for text categorization in which the importance of discriminating words is learned using mutual information and weight adjustment techniques...

  13. Multiple k Nearest Neighbor Query Processing in Spatial Network Databases

    DEFF Research Database (Denmark)

    Xuegang, Huang; Jensen, Christian Søndergaard; Saltenis, Simonas

    2006-01-01

    This paper concerns the efficient processing of multiple k nearest neighbor queries in a road-network setting. The assumed setting covers a range of scenarios such as the one where a large population of mobile service users that are constrained to a road network issue nearest-neighbor queries...... for points of interest that are accessible via the road network. Given multiple k nearest neighbor queries, the paper proposes progressive techniques that selectively cache query results in main memory and subsequently reuse these for query processing. The paper initially proposes techniques for the case...... neighbor query processing....

  14. Measurement of near neighbor separations of surface atoms

    International Nuclear Information System (INIS)

    Cohen, P.I.

    Two techniques are being developed to measure the nearest neighbor distances of atoms at the surfaces of solids. Both measures extended fine structure in the excitation probability of core level electrons which are excited by an incident electron beam. This is an important problem because the structures of most surface systems are as yet unknown, even though the location of surface atoms is the basis for any quantitative understanding of the chemistry and physics of surfaces and interfaces. These methods would allow any laboratory to make in situ determinations of surface structure in conjunction with most other laboratory probes of surfaces. Each of these two techniques has different advantages; further, the combination of the two will increase confidence in the results by reducing systematic error in the data analysis

  15. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dr. X. Geroge Xu

    2011-01-28

    A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

  16. A Saccharomyces cerevisiae-based bioassay for assessing pesticide toxicity.

    Science.gov (United States)

    Estève, Karine; Poupot, C; Dabert, P; Mietton-Peuchot, M; Milisic, V

    2009-12-01

    This study evaluates the toxic effect of three pesticides (Azoxystrobin, Cymoxanil, and Diuron) on the yeast Saccharomyces cerevisiae for the development of a new bioassay based on inhibition of S. cerevisiae metabolic activity at the level of adenosine-5-triphosphate (ATP) synthesis, as compared with two different toxicity tests based on inhibition of Daphnia magna mobility (NF EN ISO 6341) and inhibition of Vibrio fisheri activity (NF EN ISO 11348). The S. cerevisiae bioassay is cheaper and 96 times faster than the D. magna toxicity bioassay, but has lower sensitivity. It is as fast as the V. fisheri bioassay and more sensitive. Thus, this new toxicity test can be proposed for rapid detection of pesticide residues in environmental samples as a complement to the more expensive and time-consuming D. magna toxicity test.

  17. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    International Nuclear Information System (INIS)

    Xu, X. Geroge

    2011-01-01

    A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

  18. Toxicity bioassays for water from black-odor rivers in Wenzhou, China.

    Science.gov (United States)

    DeFu, He; RuiRui, Chen; EnHui, Zhu; Na, Chen; Bo, Yang; HuaHong, Shi; MinSheng, Huang

    2015-02-01

    Following urbanization, a large number of urban rivers were contaminated and turned to black-odor rivers. The traditional approach for detecting water quality is based on chemical or physical analysis. However, biological toxicity of black-odor water has been less addressed. As two typical black-odor rivers, Jiushanwai River (JS) and Shanxia River (SX) are tributaries of Wen-Rui Tang River in Wenzhou (south of China). The eco-safety of the urban rivers was evaluated by bioassay for water toxicity in this study. Ten and 5 sampling sites were respectively set along JS and SX. Water samples were collected monthly from October 2010 to October 2011. The general physical and chemical parameters of river water were monitored. In order to investigate the ecotoxicological effects of black-odor water, the following bioassays were used: (1) Fish acute toxicity test (Danio rerio, comprehensive toxicity), (2) luminescent bacteria bioassay (Qinghaiensis vibrio, toxicity to bacteria), and (3) tropical claw embryo assay (Xenopus tropicalis, embryo toxicity). Biotoxicity of black-odor rivers water was demonstrated by D. rerio, Q. vibrio, and X. tropicalis embryos. Toxicological effects of black-odor water were respectively shown by mortality of zebrafish, and by the relative inhibitory light rate of luminescent bacteria. However, luminescent bacteria were more sensitive to inspect biotoxicity than zebrafish. In X. tropicalis embryos test, toxicological effects of black-odor water were mostly shown by embryos' survival rate and teratogenic rate. Bioassay results showed that toxicity of SX water was higher than that of JS water, especially in summer. Statistical analysis of luminescent bacteria toxicity test showed that biotoxicity of SX and JS was high in summer, but low in winter and spring. The seasonal changes of water toxicity of the black-odor river were positively correlative with changes of water temperature (p water. Typical black-odor river water displays different

  19. Pinning Stabilizes Neighboring Surface Nanobubbles against Ostwald Ripening

    NARCIS (Netherlands)

    Dollet, B.; Lohse, Detlef

    2016-01-01

    Pinning of the contact line and gas oversaturation explain the stability of single surface nanobubbles. In this article, we theoretically show that the pinning also suppresses the Ostwald ripening process between neighboring surface nanobubbles, thus explaining why in a population of neighboring

  20. Frog sound identification using extended k-nearest neighbor classifier

    Science.gov (United States)

    Mukahar, Nordiana; Affendi Rosdi, Bakhtiar; Athiar Ramli, Dzati; Jaafar, Haryati

    2017-09-01

    Frog sound identification based on the vocalization becomes important for biological research and environmental monitoring. As a result, different types of feature extractions and classifiers have been employed to evaluate the accuracy of frog sound identification. This paper presents a frog sound identification with Extended k-Nearest Neighbor (EKNN) classifier. The EKNN classifier integrates the nearest neighbors and mutual sharing of neighborhood concepts, with the aims of improving the classification performance. It makes a prediction based on who are the nearest neighbors of the testing sample and who consider the testing sample as their nearest neighbors. In order to evaluate the classification performance in frog sound identification, the EKNN classifier is compared with competing classifier, k -Nearest Neighbor (KNN), Fuzzy k -Nearest Neighbor (FKNN) k - General Nearest Neighbor (KGNN)and Mutual k -Nearest Neighbor (MKNN) on the recorded sounds of 15 frog species obtained in Malaysia forest. The recorded sounds have been segmented using Short Time Energy and Short Time Average Zero Crossing Rate (STE+STAZCR), sinusoidal modeling (SM), manual and the combination of Energy (E) and Zero Crossing Rate (ZCR) (E+ZCR) while the features are extracted by Mel Frequency Cepstrum Coefficient (MFCC). The experimental results have shown that the EKNCN classifier exhibits the best performance in terms of accuracy compared to the competing classifiers, KNN, FKNN, GKNN and MKNN for all cases.

  1. Bioassay-based risk assessment of complex mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, K.C.; Safe, S.H. [Texas A& M Univ., Houston, TX (United States); Randerath, K.; Randerath, E. [College Station and Baylor College of Medicine, Houston, TX (United States)

    1994-12-31

    To compare the standard chemical-based risk assessment with in vitro genotoxicity assays, two complex environmental mixtures from a wood preserving site were analyzed in the Salmonella/microsome and E. coli prophage induction assays. Using GC/MS, sample 003 was found to contain relatively low levels of polycyclic aromatic hydrocarbons (PNAs) and elevated levels of polychlorinated dibenzo-p-dioxins (PCDDs), while sample 005 had higher levels of PNAs and relatively low levels of PCDDs. The complex mixtures were sequentially extracted with methylene chloride and methanol for analysis in Salmonella, or extracted with 1:1 hexane: acetone mixture for analysis in the prophage induction assay. At a dose of 1.0 mg/plate in Salmonella strain TA98 with metabolic activation, the methanol extract of sample 003 induced 197 net revertants, while sample 005 induced 436 net revertants. In the prophage induction assay, with activation, the hexane:acetone extract of sample 003 induced a fold increase that was slightly lower than that observed with sample 005. The estimated incremental carcinogenic risk for dermal adsorption and ingestion was 1.5E-3 for sample 003, while for sample 005 the estimated risk was 1.5E-2. Thus, the sample which induced the maximum response in both bioassays also had the highest estimated cancer risk. However, the frequency of PNA-DNA adducts in both skin and liver tissues was appreciably higher with sample 005 than with sample 003.

  2. Improving Fraudster Detection in Online Auctions by Using Neighbor-Driven Attributes

    Directory of Open Access Journals (Sweden)

    Jun-Lin Lin

    2015-12-01

    Full Text Available Online auction websites use a simple reputation system to help their users to evaluate the trustworthiness of sellers and buyers. However, to improve their reputation in the reputation system, fraudulent users can easily deceive the reputation system by creating fake transactions. This inflated-reputation fraud poses a major problem for online auction websites because it can lead legitimate users into scams. Numerous approaches have been proposed in the literature to address this problem, most of which involve using social network analysis (SNA to derive critical features (e.g., k-core, center weight, and neighbor diversity for distinguishing fraudsters from legitimate users. This paper discusses the limitations of these SNA features and proposes a class of SNA features referred to as neighbor-driven attributes (NDAs. The NDAs of users are calculated from the features of their neighbors. Because fraudsters require collusive neighbors to provide them with positive ratings in the reputation system, using NDAs can be helpful for detecting fraudsters. Although the idea of NDAs is not entirely new, experimental results on a real-world dataset showed that using NDAs improves classification accuracy compared with state-of-the-art methods that use the k-core, center weight, and neighbor diversity.

  3. Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach

    Directory of Open Access Journals (Sweden)

    Chung-Ming Own

    2015-09-01

    Full Text Available Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS, which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

  4. Velocity correlations and spatial dependencies between neighbors in a unidirectional flow of pedestrians

    Science.gov (United States)

    Porzycki, Jakub; WÄ s, Jarosław; Hedayatifar, Leila; Hassanibesheli, Forough; Kułakowski, Krzysztof

    2017-08-01

    The aim of the paper is an analysis of self-organization patterns observed in the unidirectional flow of pedestrians. On the basis of experimental data from Zhang et al. [J. Zhang et al., J. Stat. Mech. (2011) P06004, 10.1088/1742-5468/2011/06/P06004], we analyze the mutual positions and velocity correlations between pedestrians when walking along a corridor. The angular and spatial dependencies of the mutual positions reveal a spatial structure that remains stable during the crowd motion. This structure differs depending on the value of n , for the consecutive n th -nearest-neighbor position set. The preferred position for the first-nearest neighbor is on the side of the pedestrian, while for further neighbors, this preference shifts to the axis of movement. The velocity correlations vary with the angle formed by the pair of neighboring pedestrians and the direction of motion and with the time delay between pedestrians' movements. The delay dependence of the correlations shows characteristic oscillations, produced by the velocity oscillations when striding; however, a filtering of the main frequency of individual striding out reduces the oscillations only partially. We conclude that pedestrians select their path directions so as to evade the necessity of continuously adjusting their speed to their neighbors'. They try to keep a given distance, but follow the person in front of them, as well as accepting and observing pedestrians on their sides. Additionally, we show an empirical example that illustrates the shape of a pedestrian's personal space during movement.

  5. NEIGHBORING COUNTRIES’ IMAGES: PERSISTENT STEREOTYPES OF THE RUSSIAN STUDENT YOUTH

    Directory of Open Access Journals (Sweden)

    Н П Нарбут

    2017-12-01

    Full Text Available The article presents the results of the comparative study of the neighboring countries’ images in the perception of the Russian student youth. In the first part of the article, the authors emphasize the importance of public opinion as one of the key social institutions in the contemporary society though it is often manipulated by state and political organizations to ensure the public support of ambiguous decisions. There are two basic mechanisms to form social representations including the images of different countries in public opinion: spontaneous and purposeful (when officials and media use special techniques to create an image of either a dangerous enemy or the best geopolitical friend. Today in Russia the former seems to dominate for except the key geopolitical powers other countries seem to attract the state attention rather sporadically, which is supported by general political indifference, wide dissemination of information tech-nologies, and freedom of travels all over the world, etc. The second part of the article focuses on the methodological consequences of thus developing images in the Russian public opinion. The authors explain the thematic structure and techniques of the questionnaire developed for the study of the images of China, Kazakhstan and Serbia in the Russian student youth’ worldview, which were applied in the sociological survey of 2010-2011 in the project supported by the Russian Foundation for Humanities, and then again in 2016 for the comparative analysis. The last part of the article presents the results of these surveys in the comparative perspective and focuses on a few indicators to reconstruct the persistent stereotypic elements of the neighboring countries’ images in the student youth worldview though there are some changes that are difficult to interpret.

  6. How neighbor canopy architecture affects target plant performance

    Energy Technology Data Exchange (ETDEWEB)

    Tremmel, D.C.; Bazzaz, F.A. (Harvard Univ., Cambridge, MA (United States))

    1993-10-01

    Plant competition occurs through the negative effects that individual plants have on resource availability to neighboring individuals. Therefore competition experiments need to examine how different species change resource availability to their neighbors, and how different species respond to these changes-allocationally, architecturally, and physiologically-through time. In a greenhouse study we used a model system of annuals to examine how canopies of species having differing morphologies differed in their architectures and light-interception abilities, and how different species performed when grown in these canopies. Abutilon theophrasti, Datura stramonium, and Polygonum pensylvanicum were grown as [open quotes]targets[close quotes]. Plants were grown in pots, with one target plant and four neighbor plants. Detailed measurements of neighbor canopy structure and target plant canopy architecture were made at five harvests. Species with different morphologies showed large differences in canopy structure, particularly when grass and forb species were compared. Setaria, a grass, had a more open canopy than the other species (all forbs), and was a consistently weak competitor. Overall, however, the relative effects of different neighbors on target biomass varied with target species. Target biomass was poorly correlated with neighbor biomass and leaf area, but was highly correlated with a measure of target light-interception ability that took into account both target leaf deployment and neighbor light interception. Despite clear differences among neighbor species in canopy structure and effect on light penetration, the results suggest no broad generalizations about the effects of different species as neighbors. Knowledge of morphological, physiological, and life history characteristics of both the target and neighbor species may be necessary to explain the results of their competition. 53 refs., 4 figs., 4 tabs.

  7. Long-term effect of September 11 on the political behavior of victims’ families and neighbors

    Science.gov (United States)

    Hersh, Eitan D.

    2013-01-01

    This article investigates the long-term effect of September 11, 2001 on the political behaviors of victims’ families and neighbors. Relative to comparable individuals, family members and residential neighbors of victims have become—and have stayed—significantly more active in politics in the last 12 years, and they have become more Republican on account of the terrorist attacks. The method used to demonstrate these findings leverages the random nature of the terrorist attack to estimate a causal effect and exploits new techniques to link multiple, individual-level, governmental databases to measure behavioral change without relying on surveys or aggregate analysis. PMID:24324145

  8. Impact of Training Bolivian Farmers on Integrated Pest Management and Diffusion of Knowledge to Neighboring Farmers

    DEFF Research Database (Denmark)

    Jørs, Erik; Konradsen, Flemming; Huici, Omar

    2016-01-01

    Teaching farmers Integrated Pest Management (IPM) in Farmer Field Schools (FFS) has led to reduced pesticide use and safer handling. This article evaluates the long term impact of training farmers on IPM and the diffusion of knowledge from trained farmers to neighboring farmers, a subject...... the impact of the intervention, self-reported knowledge and practice on pesticide handling and IPM among trained farmers (N=23) and their neighboring farmers (N=47) were analyzed in a follow up study and compared in a cross-sectional analysis to a control group of farmers (N=138) introduced in 2009....... Variables were analyzed using χ(2)-test test and ANOVA. Trained farmers improved and performed significantly better in all tested variables than their neighboring farmers, although the latter also improved their performance from 2002 t0 2009. Including a control group showed an increasing trend in all...

  9. Our Galactic Neighbor Hosts Complex Organic Molecules

    Science.gov (United States)

    Hensley, Kerry

    2018-03-01

    For the first time, data from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the presence of methyl formate and dimethyl ether in a star-forming region outside our galaxy. This discovery has important implications for the formation and survival of complex organic compounds importantfor the formation of life in low-metallicity galaxies bothyoung and old.No Simple Picture of Complex Molecule FormationALMA, pictured here with the Magellanic Clouds above, has observed organic molecules in our Milky Way Galaxy and beyond. [ESO/C. Malin]Complex organic molecules (those with at least six atoms, one or more of which must be carbon) are the precursors to the building blocks of life. Knowing how and where complex organic molecules can form is a key part of understanding how life came to be on Earth and how it might arise elsewhere in the universe. From exoplanet atmospheres to interstellar space, complex organic molecules are ubiquitous in the Milky Way.In our galaxy, complex organic molecules are often found in the intense environments of hot cores clumps of dense molecular gas surrounding the sites of star formation. However, its not yet fully understood how the complex organic molecules found in hot cores come to be. One possibility is that the compounds condense onto cold dust grains long before the young stars begin heating their natal shrouds. Alternatively, they might assemble themselves from the hot, dense gas surrounding the blazing protostars.Composite infrared and optical image of the N 113 star-forming region in the LMC. The ALMA coverage is indicated by the gray line. Click to enlarge. [Sewio et al. 2018]Detecting Complexity, a Galaxy AwayUsing ALMA, a team of researchers led by Marta Sewio (NASA Goddard Space Flight Center) recently detected two complex organic molecules methyl formate and dimethyl ether for the first time in our neighboring galaxy, the Large Magellanic Cloud (LMC). Previous searches for organic molecules in the LMC detected

  10. A rapid fecal bioassay method for Pu/Am

    International Nuclear Information System (INIS)

    Trivedi, A.; Duong, T.; Leon, J.W.

    2000-01-01

    Fecal radiobioassay is a sensitive tool to estimate intake of radionuclides, especially for insoluble or poorly absorbed actinides. To increase efficiency and reduce turnaround time, improvements were introduced in the sample digestion step of a fecal bioassay method to rapidly detect Pu and Am. The acid- and microwave-digestion of the spiked fecal samples (5-10 g) were effectively completed in 1 h. The turnaround time for the sample analysis was minimized to 6 h. The average recoveries for Pu and Am were 35% and 60% for artificial fecal samples, respectively. Much better recoveries for Pu and Am were obtained for natural fecal samples. Observed relative biases for Pu and Am were marginally in the range of -0.25 to +0.50. The relative precision values for both radionuclides were, however, within the performance index of 0.4. This rapid fecal method is a potential candidate for an acceptable quantitative radiobioassay and screening method for the suspected Pu/Am exposures. (author)

  11. Sample preparation method for the ER-CALUX bioassay screening of (xeno-)estrogenic activity in sediment extracts

    NARCIS (Netherlands)

    Houtman, C.J.; Leonards, P.E.G.; Kapiteijn, W.; Bakker, J.F.; Brouwer, A.; Lamoree, M.H.; Legler, J.; Klamer, H.J.C.

    2007-01-01

    The application of bioassays to assess the occurrence of estrogenic compounds in the environment is increasing in both a scientific and statutory context. The availability of appropriate validated methods for sample pre-treatment and analysis is crucial for the successful implementation of

  12. Soil bioassays and the {sup 129}I problem

    Energy Technology Data Exchange (ETDEWEB)

    Sheppard, S.C. [Atomic Energy of Canada Ltd., Pinawa, Manitoba (Canada)

    1995-12-31

    Iodine-129 is a very long-lived radionuclide associated with spent nuclear fuel. Because {sup 129}I has a 10{sup 7}-year half-life, is very mobile in the environment and is a biologically essential element, it is the most limiting radionuclide affecting disposal of spent fuel. Traditionally, the potential impacts of {sup 129}I have been estimated for human receptors, with the implicit assumption that all other organisms are less at risk. Risk is the operative word, the objective for protection of humans is to protect individuals, whereas the objective for other biota is usually to protect populations. Here, {sup 129}I poses an interesting problem: the half-life is so long it is barely radioactive. Thus, the chemical toxicity may be more limiting than the radiological impact. A series of soil bioassays were employed, including a life-cycle plant (Brassica rapa) bioassay, a modified earthworm survival bioassay, a microarthropod colonization/survival bioassay, and a series of more common soil and aquatic bioassays. Chemical toxicity was indicated at soil concentrations as low as 5 mg kg{sup {minus}1}. At these levels, radiological impact on non-human biota would not be expected, and therefore the chemical toxicity effects are more critical. However, human food-chain model estimates show these levels, as pure {sup 129}I, would be unacceptable for human radiological exposure, so that for {sup 129}I, protection of the human environment should also be protective of non-human biota.

  13. Transferability of Monitoring Data from Neighboring Streams in a Physical Habitat Simulation

    Directory of Open Access Journals (Sweden)

    Byungwoong Choi

    2015-08-01

    Full Text Available Habitat simulation models heavily rely on monitoring data, which can have serious effects on the success of a physical habitat simulation. However, if data monitored in a study reach are not available or insufficient, then data from neighboring streams are commonly used. The problem is that the impact of using data from neighboring streams has rarely been studied before. Motivated by this, we report herein on an investigation of the transferability of data from neighboring streams in a physical habitat simulation. The study area is a 2.5 km long reach located downstream from a dam in the Dal River, Korea. Zacco platypus was selected as the target fish for the physical habitat simulation. Monitoring data for the Dal River and three neighboring streams were obtained. First, similarities in the data related to channel geometry and in the observed distribution of the target species were examined. Principal Component Analysis (PCA was also carried out to see the characteristics of the habitat use of the target species. Habitat Suitability Curves (HSCs were constructed using the Gene Expression Programming (GEP model, and improved Generalized Habitat Suitability Curves (GHSCs were proposed. The physical habitat simulations were then performed. The Composite Suitability Index (CSI distributions were predicted, and the impact of using data from the neighboring streams was investigated. The results indicated that the use of data from a neighboring stream even in the same watershed can result in large errors in the prediction of CSI. The physical habitat simulation with the improved GHSCs was found to best predict the CSI.

  14. Assessing the genotoxicity of urban air pollutants using two in situ plant bioassays

    International Nuclear Information System (INIS)

    Villarini, M.; Fatigoni, C.; Dominici, L.; Maestri, S.; Ederli, L.; Pasqualini, S.; Monarca, S.; Moretti, M.

    2009-01-01

    Genotoxicity of urban air has been analysed almost exclusively in airborne particulates. We monitored the genotoxic effects of airborne pollutants in the urban air of Perugia (Central Italy). Two plant bioindicators with different genetic endpoints were used: micronuclei in meiotic pollen mother cells using Tradescantia-micronucleus bioassay (Trad-MCN) and DNA damage in nuclei of Nicotiana tabacum leaves using comet assay (Nicotiana-comet). Buds of Tradescantia clone no. 4430 and young N. tabacum cv. Xanthi plants were exposed for 24 h at three sites with different pollution levels. One control site (indoor control) was also used. The two bioassays showed different sensitivities toward urban pollutants: Trad-MCN assay was the most sensitive, but DNA damage in N. tabacum showed a better correlation with the pollutant concentrations. In situ biomonitoring of airborne genotoxins using higher plants combined with chemical analysis is thus recommended for characterizing genotoxicity of urban air. - Plant bioassays used to explore in situ the correlation between air pollution and genotoxicity.

  15. Noninvasive quantitation of human liver steatosis using magnetic resonance and bioassay methods

    Energy Technology Data Exchange (ETDEWEB)

    D' Assignies, Gaspard; Ruel, Martin; Khiat, Abdesslem; Lepanto, Luigi; Kauffmann, Claude; Tang, An [Centre Hospitalier de l' Universite de Montreal (CHUM), Departement de Radiologie, Montreal, Quebec (Canada); Chagnon, Miguel [Universite de Montreal (UDEM), Departement de Mathematiques et de Statistique, Montreal, Quebec (Canada); Gaboury, Louis [Centre Hospitalier de l' Universite de Montreal (CHUM), Departement d' Anatomo-Pathologie, Montreal, Quebec (Canada); Boulanger, Yvan [Centre Hospitalier de l' Universite de Montreal (CHUM), Departement de Radiologie, Montreal, Quebec (Canada); Hopital Saint-Luc du CHUM, Departement de Radiologie, Montreal, Quebec (Canada)

    2009-08-15

    The purpose was to evaluate the ability of three magnetic resonance (MR) techniques to detect liver steatosis and to determine which noninvasive technique (MR, bioassays) or combination of techniques is optimal for the quantification of hepatic fat using histopathology as a reference. Twenty patients with histopathologically proven steatosis and 24 control subjects underwent single-voxel proton MR spectroscopy (MRS; 3 voxels), dual-echo in phase/out of phase MR imaging (DEI) and diffusion-weighted MR imaging (DWI) examinations of the liver. Blood or urine bioassays were also performed for steatosis patients. Both MRS and DEI data allowed to detect steatosis with a high sensitivity (0.95 for MRS; 1 for DEI) and specificity (1 for MRS; 0.875 for DEI) but not DWI. Strong correlations were found between fat fraction (FF) measured by MRS, DEI and histopathology segmentation as well as with low density lipoprotein (LDL) and cholesterol concentrations. A Bland-Altman analysis showed a good agreement between the FF measured by MRS and DEI. Partial correlation analyses failed to improve the correlation with segmentation FF when MRS or DEI data were combined with bioassay results. Therefore, FF from MRS or DEI appear to be the best parameters to both detect steatosis and accurately quantify fat liver noninvasively. (orig.)

  16. Rationalization of bioassay for radiation protection management in nuclear facilities

    International Nuclear Information System (INIS)

    Ishii, Keiichiro; Hattori, Takatoshi

    1989-01-01

    In this study, the objective is the rationalization of the technique of radiation protection management for internal irradiation, and we improved on utility of bioassay method. The major results obtained are as follows: 1. We develop the computing code which can analyze the behavior of excretion of radioactive nuclides and estimate the effective dose equivalent. And, we proposed the direct evaluation method of the effective dose equivalent of internal irradiation using the curve of the excretion. 2. We develop the Tiolet Monitor which can monitor the intake of 54 Mn, 137 Cs, etc. Practical screening level of Toilet Monitor is investigated as usable. 3. Any kinds of correction factors of bioassay data are investigated. 4. Practical usage of the bioassay system for management of internal irradiation protection is proposed. (author)

  17. One-Dimensional Fluids with Second Nearest-Neighbor Interactions

    Science.gov (United States)

    Fantoni, Riccardo; Santos, Andrés

    2017-12-01

    As is well known, one-dimensional systems with interactions restricted to first nearest neighbors admit a full analytically exact statistical-mechanical solution. This is essentially due to the fact that the knowledge of the first nearest-neighbor probability distribution function, p_1(r), is enough to determine the structural and thermodynamic properties of the system. On the other hand, if the interaction between second nearest-neighbor particles is turned on, the analytically exact solution is lost. Not only the knowledge of p_1(r) is not sufficient anymore, but even its determination becomes a complex many-body problem. In this work we systematically explore different approximate solutions for one-dimensional second nearest-neighbor fluid models. We apply those approximations to the square-well and the attractive two-step pair potentials and compare them with Monte Carlo simulations, finding an excellent agreement.

  18. K-Nearest Neighbor Algorithm Optimization in Text Categorization

    Science.gov (United States)

    Chen, Shufeng

    2018-01-01

    K-Nearest Neighbor (KNN) classification algorithm is one of the simplest methods of data mining. It has been widely used in classification, regression and pattern recognition. The traditional KNN method has some shortcomings such as large amount of sample computation and strong dependence on the sample library capacity. In this paper, a method of representative sample optimization based on CURE algorithm is proposed. On the basis of this, presenting a quick algorithm QKNN (Quick k-nearest neighbor) to find the nearest k neighbor samples, which greatly reduces the similarity calculation. The experimental results show that this algorithm can effectively reduce the number of samples and speed up the search for the k nearest neighbor samples to improve the performance of the algorithm.

  19. An emergency bioassay method for actinides in urine.

    Science.gov (United States)

    Dai, Xiongxin; Kramer-Tremblay, Sheila

    2011-08-01

    A rapid bioassay method has been developed for the sequential measurements of actinides in human urine samples. The method involves actinide separation from a urine matrix by co-precipitation with hydrous titanium oxide (HTiO), followed by anion exchange and extraction chromatography column purification, and final counting by alpha spectrometry after cerium fluoride micro-precipitation. The minimal detectable activities for the method were determined to be 20 mBq L(-1) or less for plutonium, uranium, americium and curium isotopes, with an 8-h sample turn-around time. Spike tests showed that this method would meet the requirements for actinide bioassay following a radiation emergency.

  20. Categorization of worker bioassay programs based on intake potential

    International Nuclear Information System (INIS)

    Thomas, S.A.; McFee, M.C.; La Bone, T.R.

    1993-01-01

    The routine bioassay program at the Savannah River Site (SRS) has undergone considerable change in the last ten years. The causes of this change may be traced to changes in personnel and regulations during this time. Prior to the 1980's, the workforce was relatively small, stable, and experienced. Bioassay programs were administered in the field by Health Protection personnel who were very familiar with all the personnel in their facility and the potential problems that could occur in those facilities. The radiation protection regulations had not changed drastically in 20 years, and they were based on readily understood quantities such as the quantity of radioactive material in the body

  1. Manual on theory and practical aspects of bioassay

    International Nuclear Information System (INIS)

    Nuraini Hambali.

    1985-06-01

    This manual is set to provide necessary basic guidance on theory and practical aspects of bioassay specially for the newcomer in this field and the man in the laboratory. The first part is a brief information on the entry of radionuclides into the body, the metabolism and the programs of bioassay. All other factors to be considered in assessing internal contamination in man have also been brought up. In the second part, various procedures of radiochemical separations, detection and measurements are abstracted from journals and other revisions. Some methods have been attempted and to be followed where appropriate. (author)

  2. Sequence correction of random coil chemical shifts: correlation between neighbor correction factors and changes in the Ramachandran distribution

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Poulsen, Flemming Martin

    2011-01-01

    Random coil chemical shifts are necessary for secondary chemical shift analysis, which is the main NMR method for identification of secondary structure in proteins. One of the largest challenges in the determination of random coil chemical shifts is accounting for the effect of neighboring residues....... The contributions from the neighboring residues are typically removed by using neighbor correction factors determined based on each residue's effect on glycine chemical shifts. Due to its unusual conformational freedom, glycine may be particularly unrepresentative for the remaining residue types. In this study, we...... in the conformational ensemble are an important source of neighbor effects in disordered proteins. Glutamine derived random coil chemical shifts and correction factors modestly improve our ability to predict (13)C chemical shifts of intrinsically disordered proteins compared to existing datasets, and may thus improve...

  3. Sensitivity bioassays of the Cnesterodon decemmaculatus and Pimephales promelasin a series of samples of effluent and reference toxicant

    Directory of Open Access Journals (Sweden)

    Gustavo Saona

    2015-12-01

    Full Text Available This study compared the toxicological sensitivity quantified by the 50% lethal dose of acute toxicity bioassays of Cnesterodon decemmaculatusand Pimephales promelasin benchmark exposure to toxic industrial effluents, wastewater effluents and reference toxicants. At the same time, the toxicological sensitivity of C. decemmaculatusrelated to the size was assayed. Both species were analyzed with 16 bioassays mated by the same substance or compound and a good agreement rL= 0.75 was observed. No significant differences in the overall analysis for effluents and potassium dichromate appeared in toxicological analysis of sensitivity to size. In contrast, significant difference in sensitivity was observed in assays with sodium dodecyl sulfate. Previous studies of the acute bioassays of C. decemmaculatusas well as the results obtained in this work accredit the use of this species in the ecotoxicological evaluation.This work contributes to generate specific ecotoxicological tools employing a native species (C. decemmaculatus and provides comparative information with an internationally accepted species used in reference bioassays (P. promelas. Progress of these studies as a priority research area will contribute to consolidate analytical tools, to develop professional skills and to strengthen institutions that manage the water resources in Uruguay.

  4. Modeling the effect of neighboring grains on twin growth in HCP polycrystals

    Science.gov (United States)

    Kumar, M. Arul; Beyerlein, I. J.; Lebensohn, R. A.; Tomé, C. N.

    2017-09-01

    In this paper, we study the dependence of neighboring grain orientation on the local stress state around a deformation twin in a hexagonal close packed (HCP) crystal and its effects on the resistance against twin thickening. We use a recently developed, full-field elasto-visco-plastic formulation based on fast Fourier transforms that account for the twinning shear transformation imposed by the twin lamella. The study is applied to Mg, Zr and Ti, since these HCP metals tend to deform by activation of different types of slip modes. The analysis shows that the local stress along the twin boundary are strongly controlled by the relative orientation of the easiest deformation modes in the neighboring grain with respect to the twin lamella in the parent grain. A geometric expression that captures this parent-neighbor relationship is proposed and incorporated into a larger scale, mean-field visco-plastic self-consistent model to simulate the role of neighboring grain orientation on twin thickening. We demonstrate that the approach improves the prediction of twin area fraction distribution when compared with experimental observations.

  5. Neighbor discovery in multi-hop wireless networks: evaluation and dimensioning with interferences considerations

    Directory of Open Access Journals (Sweden)

    Elyes Ben Hamida

    2008-04-01

    Full Text Available In this paper, we study the impact of collisions and interferences on a neighbor discovery process in the context of multi-hop wireless networks. We consider three models in which interferences and collisions are handled in very different ways. From an ideal channel where simultaneous transmissions do not interfere, we derive an alternate channel where simultaneous transmissions are considered two-by-two under the form of collisions, to finally reach a more realistic channel where simultaneous transmissions are handled under the form of shot-noise interferences. In these models, we analytically compute the link probability success between two neighbors as well as the expected number of nodes that correctly receive a Hello packet. Using this analysis, we show that if the neighbor discovery process is asymptotically equivalent in the three models, it offers very different behaviors locally in time. In particular, the scalability of the process is not the same depending on the way interferences are handled. Finally, we apply our results to the dimensioning of a Hello protocol parameters. We propose a method to adapt the protocol parameters to meet application constraints on the neighbor discovery process and to minimize the protocol energy consumption.

  6. Microplate Bioassay for Determining Substrate Selectivity of "Candida rugosa" Lipase

    Science.gov (United States)

    Wang, Shi-zhen; Fang, Bai-shan

    2012-01-01

    Substrate selectivity of "Candida rugosa" lipase was tested using "p"-nitrophenyl esters of increasing chain length (C[subscript 1], C[subscript 7], C[subscript 15]) using the high-throughput screening method. A fast and easy 96-well microplate bioassay was developed to help students learn and practice biotechnological specificity screen. The…

  7. Changes in chemical composition and bioassay assessment of ...

    African Journals Online (AJOL)

    Changes in chemical composition and bioassay assessment of nutritional potentials of almond fruit waste as an alternative feedstuff for livestock. ... AFW using day-old cockerels and considering performance parameters showed that treated AFW improved feed intake, body weight gain and feed conversion ratio even better ...

  8. Book Review: Bioassays with Arthropods: 2nd Edition

    Science.gov (United States)

    The technical book "Bioassays with Arthropods: 2nd Edition" (2007. Jacqueline L. Robertson, Robert M. Russell, Haiganoush K, Preisler and N. E. Nevin, Eds. CRC Press, Boca Raton, FL, 224 pp.) was reviewed for the scientific readership of the peer-reviewed publication Journal of Economic Entomology. ...

  9. Soil bioassays as tools for sludge compost quality assessment

    International Nuclear Information System (INIS)

    Domene, Xavier; Sola, Laura; Ramirez, Wilson; Alcaniz, Josep M.; Andres, Pilar

    2011-01-01

    Composting is a waste management technology that is becoming more widespread as a response to the increasing production of sewage sludge and the pressure for its reuse in soil. In this study, different bioassays (plant germination, earthworm survival, biomass and reproduction, and collembolan survival and reproduction) were assessed for their usefulness in the compost quality assessment. Compost samples, from two different composting plants, were taken along the composting process, which were characterized and submitted to bioassays (plant germination and collembolan and earthworm performance). Results from our study indicate that the noxious effects of some of the compost samples observed in bioassays are related to the low organic matter stability of composts and the enhanced release of decomposition endproducts, with the exception of earthworms, which are favored. Plant germination and collembolan reproduction inhibition was generally associated with uncomposted sludge, while earthworm total biomass and reproduction were enhanced by these materials. On the other hand, earthworm and collembolan survival were unaffected by the degree of composting of the wastes. However, this pattern was clear in one of the composting procedures assessed, but less in the other, where the release of decomposition endproducts was lower due to its higher stability, indicating the sensitivity and usefulness of bioassays for the quality assessment of composts.

  10. US Army Radiological Bioassay and Dosimetry: The RBD software package

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ward, R.C.; Maddox, L.B.

    1993-01-01

    The RBD (Radiological Bioassay and Dosimetry) software package was developed for the U. S. Army Material Command, Arlington, Virginia, to demonstrate compliance with the radiation protection guidance 10 CFR Part 20 (ref. 1). Designed to be run interactively on an IBM-compatible personal computer, RBD consists of a data base module to manage bioassay data and a computational module that incorporates algorithms for estimating radionuclide intake from either acute or chronic exposures based on measurement of the worker's rate of excretion of the radionuclide or the retained activity in the body. In estimating the intake,RBD uses a separate file for each radionuclide containing parametric representations of the retention and excretion functions. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent. For a given nuclide, if measurements exist for more than one type of assay, an auxiliary module, REPORT, estimates the intake by applying weights assigned in the nuclide file for each assay. Bioassay data and computed results (estimates of intake and committed dose equivalent) are stored in separate data bases, and the bioassay measurements used to compute a given result can be identified. The REPORT module creates a file containing committed effective dose equivalent for each individual that can be combined with the individual's external exposure

  11. US Army Radiological Bioassay and Dosimetry: The RBD software package

    Energy Technology Data Exchange (ETDEWEB)

    Eckerman, K. F.; Ward, R. C.; Maddox, L. B.

    1993-01-01

    The RBD (Radiological Bioassay and Dosimetry) software package was developed for the U. S. Army Material Command, Arlington, Virginia, to demonstrate compliance with the radiation protection guidance 10 CFR Part 20 (ref. 1). Designed to be run interactively on an IBM-compatible personal computer, RBD consists of a data base module to manage bioassay data and a computational module that incorporates algorithms for estimating radionuclide intake from either acute or chronic exposures based on measurement of the worker's rate of excretion of the radionuclide or the retained activity in the body. In estimating the intake,RBD uses a separate file for each radionuclide containing parametric representations of the retention and excretion functions. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent. For a given nuclide, if measurements exist for more than one type of assay, an auxiliary module, REPORT, estimates the intake by applying weights assigned in the nuclide file for each assay. Bioassay data and computed results (estimates of intake and committed dose equivalent) are stored in separate data bases, and the bioassay measurements used to compute a given result can be identified. The REPORT module creates a file containing committed effective dose equivalent for each individual that can be combined with the individual's external exposure.

  12. Initial sample extract stock concentration affects in vitro bioassay-based toxicological risk characterization

    NARCIS (Netherlands)

    Montano, M.; Loffmann, L.; Murk, A.J.; Gutleb, A.C.

    2014-01-01

    Purpose Bioassays have become an alternative for sediment risk profiling, including potential compliance with sediment quality criteria (SQC). In vitro functional bioassays have evolved through standardization and validation towards a confident toxicological hazard estimate of sediments. Sample

  13. Strategies for Transferring Mixtures of Organic Contaminants from Aquatic Environments into Bioassays

    DEFF Research Database (Denmark)

    Jahnke, Annika; Mayer, Philipp; Schäfer, Sabine

    2016-01-01

    into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total extraction...

  14. Investigation of independence in inter-animal tumor-type occurrences within the NTP rodent-bioassay database

    Energy Technology Data Exchange (ETDEWEB)

    Bogen, K.T. [Lawrence Livermore National Lab., CA (United States); Seilkop, S. [Analytical Sciences, Inc., Durham, NC (United States)

    1993-05-01

    Statistically significant elevation in tumor incidence at multiple histologically distinct sites is occasionally observed among rodent bioassays of chemically induced carcinogenesis. If such data are to be relied on (as they have, e.g., by the US EPA) for quantitative cancer potency assessment, their proper analysis requires a knowledge of the extent to which multiple tumor-type occurrences are independent or uncorrelated within individual bioassay animals. Although difficult to assess in a statistically rigorous fashion, a few significant associations among tumor-type occurrences in rodent bioassays have been reported. However, no comprehensive studies of animal-specific tumor-type occurrences at death or sacrifice have been conducted using the extensive set of available NTP rodent-bioassay data, on which most cancer-potency assessment for environmental chemicals is currently based. This report presents the results of such an analysis conducted on behalf of the National Research Council`s Committee on Risk Assessment for Hazardous Air Pollutants. Tumor-type associations among individual animals were examined for {approximately}2500 to 3000 control and {approximately}200 to 600 treated animals using pathology data from 62 B6C3F1 mouse studies and 61 F/344N rat studies obtained from a readily available subset of the NTP carcinogenesis bioassay database. No evidence was found for any large correlation in either the onset probability or the prevalence-at-death or sacrifice of any tumor-type pair investigated in control and treated rats and niece, although a few of the small correlations present were statistically significant. Tumor-type occurrences were in most cases nearly independent, and departures from independence, where they did occur, were small. This finding is qualified in that tumor-type onset correlations were measured only indirectly, given the limited nature of the data analyzed.

  15. River Flow Prediction Using the Nearest Neighbor Probabilistic Ensemble Method

    Directory of Open Access Journals (Sweden)

    H. Sanikhani

    2016-02-01

    Full Text Available Introduction: In the recent years, researchers interested on probabilistic forecasting of hydrologic variables such river flow.A probabilistic approach aims at quantifying the prediction reliability through a probability distribution function or a prediction interval for the unknown future value. The evaluation of the uncertainty associated to the forecast is seen as a fundamental information, not only to correctly assess the prediction, but also to compare forecasts from different methods and to evaluate actions and decisions conditionally on the expected values. Several probabilistic approaches have been proposed in the literature, including (1 methods that use resampling techniques to assess parameter and model uncertainty, such as the Metropolis algorithm or the Generalized Likelihood Uncertainty Estimation (GLUE methodology for an application to runoff prediction, (2 methods based on processing the forecast errors of past data to produce the probability distributions of future values and (3 methods that evaluate how the uncertainty propagates from the rainfall forecast to the river discharge prediction, as the Bayesian forecasting system. Materials and Methods: In this study, two different probabilistic methods are used for river flow prediction.Then the uncertainty related to the forecast is quantified. One approach is based on linear predictors and in the other, nearest neighbor was used. The nonlinear probabilistic ensemble can be used for nonlinear time series analysis using locally linear predictors, while NNPE utilize a method adapted for one step ahead nearest neighbor methods. In this regard, daily river discharge (twelve years of Dizaj and Mashin Stations on Baranduz-Chay basin in west Azerbijan and Zard-River basin in Khouzestan provinces were used, respectively. The first six years of data was applied for fitting the model. The next three years was used to calibration and the remained three yeas utilized for testing the models

  16. Bioassay for aquatic ecosystems review and classification; Rassegna dei principali test di ecotossicologia acquatica

    Energy Technology Data Exchange (ETDEWEB)

    Sanci, Antonella; Rosa, Silvia [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1997-09-01

    Bioassay play a crucial role in assessing the actual or potential impacts of anthropogenic agents on the natural environment. In this technical report, literature on bioassays for aquatic ecosystems has been reviewed and classified. Problems associated with the choice and application of bioassays are discussed.

  17. Atomic process modeling based on nearest neighbor approximation

    International Nuclear Information System (INIS)

    Nishikawa, Takeshi

    2016-01-01

    An atomic modeling based on the nearest neighbor approximation (NNA) to solove atomic process in plasmas was considered. In the atomic modeling, it includes the plasma effect to the electron state densities of the atom or ion as the potential due to the nearest neighbor atom or ion. Using the modeling, I was able to compute the ionization degrees of hydrogen plasmas without any ad hoc assumption adopted in the atomic modeling based on the plasma microfield. In order to apply the NNA to the plasmas of near and above solid density, three adequate treatments were required to obtain physically acceptable results. The first one was the Coulomb interaction between pairs of ions. The second one was the modification of the Saha equation. The third one was the adequate treatment of the neutral atom's contribution to the potential distribution as the nearest neighbor particle. (author)

  18. Bioassays as one of the Green Chemistry tools for assessing environmental quality: A review.

    Science.gov (United States)

    Wieczerzak, M; Namieśnik, J; Kudłak, B

    2016-09-01

    For centuries, mankind has contributed to irreversible environmental changes, but due to the modern science of recent decades, scientists are able to assess the scale of this impact. The introduction of laws and standards to ensure environmental cleanliness requires comprehensive environmental monitoring, which should also meet the requirements of Green Chemistry. The broad spectrum of Green Chemistry principle applications should also include all of the techniques and methods of pollutant analysis and environmental monitoring. The classical methods of chemical analyses do not always match the twelve principles of Green Chemistry, and they are often expensive and employ toxic and environmentally unfriendly solvents in large quantities. These solvents can generate hazardous and toxic waste while consuming large volumes of resources. Therefore, there is a need to develop reliable techniques that would not only meet the requirements of Green Analytical Chemistry, but they could also complement and sometimes provide an alternative to conventional classical analytical methods. These alternatives may be found in bioassays. Commercially available certified bioassays often come in the form of ready-to-use toxkits, and they are easy to use and relatively inexpensive in comparison with certain conventional analytical methods. The aim of this study is to provide evidence that bioassays can be a complementary alternative to classical methods of analysis and can fulfil Green Analytical Chemistry criteria. The test organisms discussed in this work include single-celled organisms, such as cell lines, fungi (yeast), and bacteria, and multicellular organisms, such as invertebrate and vertebrate animals and plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Bioassay-directed identification of toxicants in sediments of Liaohe River, northeast China.

    Science.gov (United States)

    He, Yan; Xu, Jian; Guo, Changsheng; Lv, Jiapei; Zhang, Yuan; Meng, Wei

    2016-12-01

    Contaminants accumulated in sediments may directly harm benthic organisms, however, the specific contaminants responsible for adverse effects have been poorly described. In this study, a bioassay-directed analysis combined with toxicity tests and chemistry analysis was conducted to determine the compounds eliciting the greatest toxicological effect in the sediments in Liaohe River, northeast China. A total of 24 sediment samples were examined to determine their acute toxicity to midge Chironomus tentans (C. tentans). Of these samples, 15 exhibited significant toxicity, with a mortality of 23%-93% (p organochlorine pesticides, 6 organophosphate pesticides, 8 pyrethroids, and 5 heavy metals were analyzed. On the basis of toxic unit (TU) analysis results, pyrethroids may contribute to the toxicity of 9 of the 15 toxic samples with concentrations of >1 TU. The significant correlation between the TUs of pyrethroids and the mortality of C. tentans (r 2  = 0.74, p < 0.01) confirmed the major role of pyrethroids in toxicity. The selected sediment samples responding to piperonyl butoxide and low temperature with the increased toxicity exhibited the characteristics of pyrethroids. The bioassay-based screening framework provided strong evidence that pyrethroids were the primary cause of sediment toxicity in Liaohe River. Further studies should therefore be conducted to regulate this important class of pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Near Neighbor Distribution in Sets of Fractal Nature

    Czech Academy of Sciences Publication Activity Database

    Jiřina, Marcel

    2013-01-01

    Roč. 5, č. 1 (2013), s. 159-166 ISSN 2150-7988 R&D Projects: GA MŠk(CZ) LG12020 Institutional support: RVO:67985807 Keywords : nearest neighbor * fractal set * multifractal * Erlang distribution Subject RIV: BB - Applied Statistics, Operational Research http://www.mirlabs.org/ijcisim/regular_papers_2013/Paper91.pdf

  1. Contrasting demographic histories of the neighboring bonobo and chimpanzee

    DEFF Research Database (Denmark)

    Hvilsom, Christina; Carlsen, Frands; Heller, Rasmus

    2014-01-01

    of the neighboring bonobo remained constant. The changes in population size are likely linked to changes in habitat area due to climate oscillations during the late Pleistocene. Furthermore, the timing of population expansion for the rainforest-adapted chimpanzee is concurrent with the expansion of the savanna...

  2. Grain price spikes and beggar-thy-neighbor policy responses

    DEFF Research Database (Denmark)

    Boysen, Ole; Jensen, Hans Grinsted

    Upward spikes in the international price of food in recent years led some countries to raise export barriers, thereby exacerbating both the price spike and reducing the terms of trade for food-importing countries (beggaring their neighbors). At the same time, and for similar political...

  3. Secure Nearest Neighbor Query on Crowd-Sensing Data

    Directory of Open Access Journals (Sweden)

    Ke Cheng

    2016-09-01

    Full Text Available Nearest neighbor queries are fundamental in location-based services, and secure nearest neighbor queries mainly focus on how to securely and quickly retrieve the nearest neighbor in the outsourced cloud server. However, the previous big data system structure has changed because of the crowd-sensing data. On the one hand, sensing data terminals as the data owner are numerous and mistrustful, while, on the other hand, in most cases, the terminals find it difficult to finish many safety operation due to computation and storage capability constraints. In light of they Multi Owners and Multi Users (MOMU situation in the crowd-sensing data cloud environment, this paper presents a secure nearest neighbor query scheme based on the proxy server architecture, which is constructed by protocols of secure two-party computation and secure Voronoi diagram algorithm. It not only preserves the data confidentiality and query privacy but also effectively resists the collusion between the cloud server and the data owners or users. Finally, extensive theoretical and experimental evaluations are presented to show that our proposed scheme achieves a superior balance between the security and query performance compared to other schemes.

  4. Local-Nearest-Neighbors-Based Feature Weighting for Gene Selection.

    Science.gov (United States)

    An, Shuai; Wang, Jun; Wei, Jinmao

    2017-06-07

    Selecting functional genes is essential for analyzing microarray data. Among many available feature (gene) selection approaches, the ones on the basis of the large margin nearest neighbor receive more attention due to their low computational costs and high accuracies in analyzing the high-dimensional data. Yet there still exist some problems that hamper the existing approaches in sifting real target genes, including selecting erroneous nearest neighbors, high sensitivity to irrelevant genes, and inappropriate evaluation criteria. Previous pioneer works have partly addressed some of the problems, but none of them are capable of solving these problems simultaneously. In this paper, we propose a new local-nearest-neighbors-based feature weighting approach to alleviate the above problems. The proposed approach is based on the trick of locally minimizing the within-class distances and maximizing the between-class distances with the k nearest neighbors rule. We further define a feature weight vector, and construct it by minimizing the cost function with a regularization term. The proposed approach can be applied naturally to the multi-class problems and does not require extra modification. Experimental results on the UCI and the open microarray data sets validate the effectiveness and efficiency of the new approach.

  5. Clustered K nearest neighbor algorithm for daily inflow forecasting

    NARCIS (Netherlands)

    Akbari, M.; Van Overloop, P.J.A.T.M.; Afshar, A.

    2010-01-01

    Instance based learning (IBL) algorithms are a common choice among data driven algorithms for inflow forecasting. They are based on the similarity principle and prediction is made by the finite number of similar neighbors. In this sense, the similarity of a query instance is estimated according to

  6. Neighboring Genes Show Correlated Evolution in Gene Expression

    Science.gov (United States)

    Ghanbarian, Avazeh T.; Hurst, Laurence D.

    2015-01-01

    When considering the evolution of a gene’s expression profile, we commonly assume that this is unaffected by its genomic neighborhood. This is, however, in contrast to what we know about the lack of autonomy between neighboring genes in gene expression profiles in extant taxa. Indeed, in all eukaryotic genomes genes of similar expression-profile tend to cluster, reflecting chromatin level dynamics. Does it follow that if a gene increases expression in a particular lineage then the genomic neighbors will also increase in their expression or is gene expression evolution autonomous? To address this here we consider evolution of human gene expression since the human-chimp common ancestor, allowing for both variation in estimation of current expression level and error in Bayesian estimation of the ancestral state. We find that in all tissues and both sexes, the change in gene expression of a focal gene on average predicts the change in gene expression of neighbors. The effect is highly pronounced in the immediate vicinity (genes increasing their expression in humans tend to avoid nuclear lamina domains and be enriched for the gene activator 5-hydroxymethylcytosine, we conclude that, most probably owing to chromatin level control of gene expression, a change in gene expression of one gene likely affects the expression evolution of neighbors, what we term expression piggybacking, an analog of hitchhiking. PMID:25743543

  7. Local randomization in neighbor selection improves PRM roadmap quality

    KAUST Repository

    McMahon, Troy

    2012-10-01

    Probabilistic Roadmap Methods (PRMs) are one of the most used classes of motion planning methods. These sampling-based methods generate robot configurations (nodes) and then connect them to form a graph (roadmap) containing representative feasible pathways. A key step in PRM roadmap construction involves identifying a set of candidate neighbors for each node. Traditionally, these candidates are chosen to be the k-closest nodes based on a given distance metric. In this paper, we propose a new neighbor selection policy called LocalRand(k,K\\'), that first computes the K\\' closest nodes to a specified node and then selects k of those nodes at random. Intuitively, LocalRand attempts to benefit from random sampling while maintaining the higher levels of local planner success inherent to selecting more local neighbors. We provide a methodology for selecting the parameters k and K\\'. We perform an experimental comparison which shows that for both rigid and articulated robots, LocalRand results in roadmaps that are better connected than the traditional k-closest policy or a purely random neighbor selection policy. The cost required to achieve these results is shown to be comparable to k-closest. © 2012 IEEE.

  8. Application and Interpretation of Bioassay and Biomonitoring: A Planning Document.

    Science.gov (United States)

    1987-10-13

    earthworm ( Eisenia foetida ) bioassay should be conducted on the air- dried dredged material or sediment to allow for the evaluation of the effects of...Methodology Earthworms, Eisenia foetida , were placed in a reduced; highly contaminated, sediment from a freshwater harbor as a screening test prior to the...earthworm, Eisen!a foetida . The most consequential environmental effects of persistent contaminants are expected to be found at the level of the soil

  9. Local biotic adaptation of trees and shrubs to plant neighbors

    Science.gov (United States)

    Grady, Kevin C.; Wood, Troy E.; Kolb, Thomas E.; Hersch-Green, Erika; Shuster, Stephen M.; Gehring, Catherine A.; Hart, Stephen C.; Allan, Gerard J.; Whitham, Thomas G.

    2017-01-01

    Natural selection as a result of plant–plant interactions can lead to local biotic adaptation. This may occur where species frequently interact and compete intensely for resources limiting growth, survival, and reproduction. Selection is demonstrated by comparing a genotype interacting with con- or hetero-specific sympatric neighbor genotypes with a shared site-level history (derived from the same source location), to the same genotype interacting with foreign neighbor genotypes (from different sources). Better genotype performance in sympatric than allopatric neighborhoods provides evidence of local biotic adaptation. This pattern might be explained by selection to avoid competition by shifting resource niches (differentiation) or by interactions benefitting one or more members (facilitation). We tested for local biotic adaptation among two riparian trees, Populus fremontii and Salix gooddingii, and the shrub Salix exigua by transplanting replicated genotypes from multiple source locations to a 17 000 tree common garden with sympatric and allopatric treatments along the Colorado River in California. Three major patterns were observed: 1) across species, 62 of 88 genotypes grew faster with sympatric neighbors than allopatric neighbors; 2) these growth rates, on an individual tree basis, were 44, 15 and 33% higher in sympatric than allopatric treatments for P. fremontii, S. exigua and S. gooddingii, respectively, and; 3) survivorship was higher in sympatric treatments for P. fremontiiand S. exigua. These results support the view that fitness of foundation species supporting diverse communities and dominating ecosystem processes is determined by adaptive interactions among multiple plant species with the outcome that performance depends on the genetic identity of plant neighbors. The occurrence of evolution in a plant-community context for trees and shrubs builds on ecological evolutionary research that has demonstrated co-evolution among herbaceous taxa, and

  10. Non-local neighbor embedding image denoising algorithm in sparse domain

    Science.gov (United States)

    Shi, Guo-chuan; Xia, Liang; Liu, Shuang-qing; Xu, Guo-ming

    2013-12-01

    To get better denoising results, the prior knowledge of nature images should be taken into account to regularize the ill-posed inverse problem. In this paper, we propose an image denoising algorithm via non-local similar neighbor embedding in sparse domain. Firstly, a local statistical feature, namely histograms of oriented gradients of image patches is used to perform the clustering, and then the whole training data set is partitioned into a set of subsets which have similar local geometric structures and the centroid of each subset is also obtained. Secondly, we apply the principal component analysis (PCA) to learn the compact sub-dictionary for each cluster. Next, through sparse coding over the sub-dictionary and neighborhood selecting, the image patch to be synthesized can be approximated by its top k neighbors. The extensive experimental results validate the effective of the proposed method both in PSNR and visual perception.

  11. Establishment of fecal bioassay facility at Kalpakkam

    International Nuclear Information System (INIS)

    Krishnan, H.; Yuvaraj, Ramani; Mohanty, B.N.; Sivasubramanian, K.; Venkatraman, B.

    2016-01-01

    In the event of an unusual occurrence, occupational radiation workers employed in fuel reprocessing/fuel fabrication facilities have potential risk of acquiring internal contamination, in spite of implementation of efficient engineering and administrative control measures. Quantification of internally deposited radionuclides is achieved either by (i) direct methods and/or (ii) indirect methods. In general, urinalysis is preferred for moderately absorbing (Type M-compounds of Americium) compounds, while analysis of fecal samples are preferred for slow absorption (Type S - Oxides of Plutonium) compounds. The predicted clearance of Type S and Type M compounds deposited in respiratory tract via fecal is about three to five orders higher than urinary excretion. In view of this, a facility for ashing fecal samples was established and standardization of radioanalytical procedure for quantification of Pu/Am using synthetic fecal (SF) samples was carried out

  12. Novel bioassay using Bacillus megaterium to detect tetracycline in milk.

    Science.gov (United States)

    Tumini, Melisa; Nagel, Orlando G; Molina, Pilar; Althaus, Rafael L

    2016-01-01

    Tetracyclines are used for the prevention and control of dairy cattle diseases. Residues of these drugs can be excreted into milk. Thus, the aim of this study was to develop a microbiological method using Bacillus megaterium to detect tetracyclines (chlortetracycline, oxytetracycline and tetracycline) in milk. In order to approximate the limits of detection of the bioassay to the Maximum Residue Limit (100μg/l) for milk tetracycline, different concentrations of chloramphenicol (0, 1000, 1500 and 2000μg/l) were tested. The detection limits calculated were similar to the Maximum Residue Limits when a bioassay using B. megaterium ATCC 9885 spores (2.8×10(8)spores/ml) and chloramphenicol (2000μg/l) was utilized. This bioassay detects 105μg/l of chlortetracycline, 100μg/l of oxytetracycline and 134μg/l of tetracycline in 5h. Therefore, this method is suitable to be incorporated into a microbiological multi-residue system for the identification of tetracyclines in milk. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Tradescantia-micronucleus bioassay for detection of carcinogens.

    Science.gov (United States)

    Ma, T H

    2001-01-01

    The Tradescantia-Micronucleus (Trad-MCN) bioassay is one of the tests used in the International Program on Plant bioassays (IPPB) under the auspices of the United Nations Environment Programme (UNEP). Using chromosome damage as the indicator of the carcinogenic properties of environmental agents, the Trad-MCN bioassay is a quick and efficient tool for screening carcinogens in gaseous, liquid and solid forms. Test results can be obtained within 24-48 hr after the exposure either on site or in the laboratory. The international standard protocol of this test was published in 1994 and a list of test results of carcinogens and clastogens compiled from publications in the last 23 years will be presented. Under the IPPB/UNEP, more than 40 institutes including public health, medical and cancer research in the major countries of the world are carrying on the monitoring task on genotoxicity of polluted air, water and soil. At the same time, the Trad-MCN can be used in a global scale to detect carcinogens as a preventive measure of cancer.

  14. Fast and accurate semantic annotation of bioassays exploiting a hybrid of machine learning and user confirmation

    Directory of Open Access Journals (Sweden)

    Alex M. Clark

    2014-08-01

    Full Text Available Bioinformatics and computer aided drug design rely on the curation of a large number of protocols for biological assays that measure the ability of potential drugs to achieve a therapeutic effect. These assay protocols are generally published by scientists in the form of plain text, which needs to be more precisely annotated in order to be useful to software methods. We have developed a pragmatic approach to describing assays according to the semantic definitions of the BioAssay Ontology (BAO project, using a hybrid of machine learning based on natural language processing, and a simplified user interface designed to help scientists curate their data with minimum effort. We have carried out this work based on the premise that pure machine learning is insufficiently accurate, and that expecting scientists to find the time to annotate their protocols manually is unrealistic. By combining these approaches, we have created an effective prototype for which annotation of bioassay text within the domain of the training set can be accomplished very quickly. Well-trained annotations require single-click user approval, while annotations from outside the training set domain can be identified using the search feature of a well-designed user interface, and subsequently used to improve the underlying models. By drastically reducing the time required for scientists to annotate their assays, we can realistically advocate for semantic annotation to become a standard part of the publication process. Once even a small proportion of the public body of bioassay data is marked up, bioinformatics researchers can begin to construct sophisticated and useful searching and analysis algorithms that will provide a diverse and powerful set of tools for drug discovery researchers.

  15. Establishing principal soil quality parameters influencing earthworms in urban soils using bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Hankard, Peter K. [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon PE28 2LS (United Kingdom)]. E-mail: pkh@ceh.ac.uk; Bundy, Jacob G. [University of Cambridge, Department of Biochemistry, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Spurgeon, David J. [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon PE28 2LS (United Kingdom); Weeks, Jason M. [WRc-NSF Ltd, Henley Road, Medmenham, Marlow, Buckinghamshire SL7 2HD (United Kingdom); Wright, Julian [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon PE28 2LS (United Kingdom); Weinberg, Claire [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon PE28 2LS (United Kingdom); Svendsen, Claus [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon PE28 2LS (United Kingdom)

    2005-01-01

    Potential contamination at ex-industrial sites means that, prior to change of use, it will be necessary to quantify the extent of risks to potential receptors. To assess ecological hazards, it is often suggested to use biological assessment to augment chemical analyses. Here we investigate the potential of a commonly recommended bioassay, the earthworm reproduction test, to assess the status of urban contaminated soils. Sample points at all study sites had contaminant concentrations above the Dutch soil criteria Target Values. In some cases, the relevant Intervention Values were exceeded. Earthworm survival at most points was high, but reproduction differed significantly in soil from separate patches on the same site. When the interrelationships between soil parameters and reproduction were studied, it was not possible to create a good model of site soil toxicity based on single or even multiple chemical measurements of the soils. We thus conclude that chemical analysis alone is not sufficient to characterize soil quality and confirms the value of biological assays for risk assessment of potentially contaminated soils. - Bioassays must be applied for the risk assessment complexly-polluted sites to complement chemical analysis of soils.

  16. Integrated estuary management for diffused sediment pollution in Dapeng Bay and neighboring rivers (Taiwan).

    Science.gov (United States)

    Chung, Chung-Yi; Chen, Jen-Jeng; Lee, Chang-Gai; Chiu, Chun-Yen; Lai, Wen-Liang; Liao, Shao-Wei

    2011-02-01

    This work investigated sediment samples collected from Dapeng Bay and three neighboring rivers (Kaoping River, Tungkang River, and Lingbeng River) in southwestern Taiwan, Republic of China. Multivariate statistical analysis techniques, i.e., factor analysis, cluster analysis, and canonical discriminant analysis were used for the evaluation of spatial variations to determine the types of pollution and to identify pollutant sources from neighboring rivers. Factor analysis results showed that the most important latent factors in Dapeng Bay are soil texture, heavy metals, organic matter, and nutrients factors. Contour maps incorporating the factor scores showed heavy metals accumulate along the lakesides, especially on the southeastern banks of the lakes. A cluster analysis was performed using factor scores computed from these latent factors. We then classified these areas into five distinct classes using sampling stations, and we illustrate that in the three river classes, the sediment properties are influenced by industrial and domestic wastewater and agricultural activities (including livestock rearing and farm activities). However, in Dapeng Bay, the rivers were influenced more by complicated biogeochemical processes; these could be identified as a type of pollution. Canonical discriminant analysis illustrated that two constructed discriminant functions made a marked contribution to most of the discriminant variables, and the significant parameters of porosity and Cd, Cr, Al, and Pb content were combined as the "heavy metal factor". The recognition capacities of the two discriminant functions were 82.6% and 17.4%, respectively. It is also likely that the annual mean of the water exchange rate is insufficient (taking about 7 days to eliminate pollutants) and therefore has significantly influenced the carbon and nutrient biogeochemical processes and budgets in the semi-enclosed ecosystem. Thus, the sediment properties are not similar between the lagoon and the

  17. Interference and differentiation of the neighboring surface microcracks in distributed sensing with PPP-BOTDA.

    Science.gov (United States)

    Meng, Dewei; Ansari, Farhad

    2016-12-01

    Detection of cracks while at their early stages of evolution is important in health monitoring of civil structures. Review of technical literature reveals that single or sparsely distributed multiple cracks can be detected by Brillouin-scattering-based optical fiber sensor systems. In a recent study, a pre-pump-pulse Brillouin optical time-domain analysis (PPP-BOTDA) system was employed for detection of a single microcrack. Specific characteristics of the Brillouin gain spectrum, such as Brillouin frequency shift, and Brillouin gain spectrum width, were utilized in order to detect the formation and growth of microcracks with crack opening displacements as small as 25 μm. In most situations, formations of neighboring microcracks are not detected due to inherent limitations of Brillouin-based systems. In the study reported here, the capability of PPP-BOTDA for detection of two neighboring microcracks was investigated in terms of the proximity of the microcracks with respect to each other, i.e., crack spacing distance, crack opening displacement, and the spatial resolution of the PPP-BOTDA. The extent of the study pertained both to theoretical as well as experimental investigations. The concept of shape index is introduced in order to establish an analytical method for gauging the influence of the neighboring microcracks in detection and microcrack differentiation capabilities of Brillouin-based optical fiber sensor systems.

  18. Protein function prediction using neighbor relativity in protein-protein interaction network.

    Science.gov (United States)

    Moosavi, Sobhan; Rahgozar, Masoud; Rahimi, Amir

    2013-04-01

    There is a large gap between the number of discovered proteins and the number of functionally annotated ones. Due to the high cost of determining protein function by wet-lab research, function prediction has become a major task for computational biology and bioinformatics. Some researches utilize the proteins interaction information to predict function for un-annotated proteins. In this paper, we propose a novel approach called "Neighbor Relativity Coefficient" (NRC) based on interaction network topology which estimates the functional similarity between two proteins. NRC is calculated for each pair of proteins based on their graph-based features including distance, common neighbors and the number of paths between them. In order to ascribe function to an un-annotated protein, NRC estimates a weight for each neighbor to transfer its annotation to the unknown protein. Finally, the unknown protein will be annotated by the top score transferred functions. We also investigate the effect of using different coefficients for various types of functions. The proposed method has been evaluated on Saccharomyces cerevisiae and Homo sapiens interaction networks. The performance analysis demonstrates that NRC yields better results in comparison with previous protein function prediction approaches that utilize interaction network. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Using nearest neighbors for accurate estimation of ultrasonic attenuation in the spectral domain.

    Science.gov (United States)

    Hasan, Md Kamrul; Hussain, Mohammad Arafat; Ara, Sharmin R; Lee, Soo Yeol; Alam, S Kaisar

    2013-06-01

    Attenuation is a key diagnostic parameter of tissue pathology change and thus may play a vital role in the quantitative discrimination of malignant and benign tumors in soft tissue. In this paper, two novel techniques are proposed for estimating the average ultrasonic attenuation in soft tissue using the spectral domain weighted nearest neighbor method. Because the attenuation coefficient of soft tissues can be considered to be a continuous function in a small neighborhood, we directly estimate an average value of it from the slope of the regression line fitted to the 1) modified average midband fit value and 2) the average center frequency shift along the depth. To calculate the average midband fit value, an average regression line computed from the exponentially weighted short-time Fourier transform (STFT) of the neighboring 1-D signal blocks, in the axial and lateral directions, is fitted over the usable bandwidth of the normalized power spectrum. The average center frequency downshift is computed from the maximization of a cost function defined from the normalized spectral cross-correlation (NSCC) of exponentially weighted nearest neighbors in both directions. Different from the large spatial signal-block-based spectral stability approach, a costfunction- based approach incorporating NSCC functions of neighboring 1-D signal blocks is introduced. This paves the way for using comparatively smaller spatial area along the lateral direction, a necessity for producing more realistic attenuation estimates for heterogeneous tissue. For accurate estimation of the attenuation coefficient, we also adopt a reference-phantombased diffraction-correction technique for both methods. The proposed attenuation estimation algorithm demonstrates better performance than other reported techniques in the tissue-mimicking phantom and the in vivo breast data analysis.

  20. Airborne Signals from a Wounded Leaf Facilitate Viral Spreading and Induce Antibacterial Resistance in Neighboring Plants

    Science.gov (United States)

    Dorokhov, Yuri L.; Komarova, Tatiana V.; Petrunia, Igor V.; Frolova, Olga Y.; Pozdyshev, Denis V.; Gleba, Yuri Y.

    2012-01-01

    Many plants release airborne volatile compounds in response to wounding due to pathogenic assault. These compounds serve as plant defenses and are involved in plant signaling. Here, we study the effects of pectin methylesterase (PME)-generated methanol release from wounded plants (“emitters”) on the defensive reactions of neighboring “receiver” plants. Plant leaf wounding resulted in the synthesis of PME and a spike in methanol released into the air. Gaseous methanol or vapors from wounded PME-transgenic plants induced resistance to the bacterial pathogen Ralstonia solanacearum in the leaves of non-wounded neighboring “receiver” plants. In experiments with different volatile organic compounds, gaseous methanol was the only airborne factor that could induce antibacterial resistance in neighboring plants. In an effort to understand the mechanisms by which methanol stimulates the antibacterial resistance of “receiver” plants, we constructed forward and reverse suppression subtractive hybridization cDNA libraries from Nicotiana benthamiana plants exposed to methanol. We identified multiple methanol-inducible genes (MIGs), most of which are involved in defense or cell-to-cell trafficking. We then isolated the most affected genes for further analysis: β-1,3-glucanase (BG), a previously unidentified gene (MIG-21), and non-cell-autonomous pathway protein (NCAPP). Experiments with Tobacco mosaic virus (TMV) and a vector encoding two tandem copies of green fluorescent protein as a tracer of cell-to-cell movement showed the increased gating capacity of plasmodesmata in the presence of BG, MIG-21, and NCAPP. The increased gating capacity is accompanied by enhanced TMV reproduction in the “receivers”. Overall, our data indicate that methanol emitted by a wounded plant acts as a signal that enhances antibacterial resistance and facilitates viral spread in neighboring plants. PMID:22496658

  1. Social dilemma alleviated by sharing the gains with immediate neighbors

    Science.gov (United States)

    Wu, Zhi-Xi; Yang, Han-Xin

    2014-01-01

    We study the evolution of cooperation in the evolutionary spatial prisoner's dilemma game (PDG) and snowdrift game (SG), within which a fraction α of the payoffs of each player gained from direct game interactions is shared equally by the immediate neighbors. The magnitude of the parameter α therefore characterizes the degree of the relatedness among the neighboring players. By means of extensive Monte Carlo simulations as well as an extended mean-field approximation method, we trace the frequency of cooperation in the stationary state. We find that plugging into relatedness can significantly promote the evolution of cooperation in the context of both studied games. Unexpectedly, cooperation can be more readily established in the spatial PDG than that in the spatial SG, given that the degree of relatedness and the cost-to-benefit ratio of mutual cooperation are properly formulated. The relevance of our model with the stakeholder theory is also briefly discussed.

  2. Interaction between neighboring vegetation patches: impact on flow and deposition

    OpenAIRE

    Meire, Dieter; Kondziolka, John; Nepf, Heidi

    2014-01-01

    Flow and sedimentation around patches of vegetation are important to landscape evolution, and a better understanding of these processes would facilitate more effective river restoration and wetlands engineering. In wetlands and channels, patches of vegetation are rarely isolated and neighboring patches influence one another during their development. In this experimental study, an adjacent pair of emergent vegetation patches were modeled by circular arrays of cylinders with their centers align...

  3. Do alcohol compliance checks decrease underage sales at neighboring establishments?

    Science.gov (United States)

    Erickson, Darin J; Smolenski, Derek J; Toomey, Traci L; Carlin, Bradley P; Wagenaar, Alexander C

    2013-11-01

    Underage alcohol compliance checks conducted by law enforcement agencies can reduce the likelihood of illegal alcohol sales at checked alcohol establishments, and theory suggests that an alcohol establishment that is checked may warn nearby establishments that compliance checks are being conducted in the area. In this study, we examined whether the effects of compliance checks diffuse to neighboring establishments. We used data from the Complying with the Minimum Drinking Age trial, which included more than 2,000 compliance checks conducted at more than 900 alcohol establishments. The primary outcome was the sale of alcohol to a pseudo-underage buyer without the need for age identification. A multilevel logistic regression was used to model the effect of a compliance check at each establishment as well as the effect of compliance checks at neighboring establishments within 500 m (stratified into four equal-radius concentric rings), after buyer, license, establishment, and community-level variables were controlled for. We observed a decrease in the likelihood of establishments selling alcohol to underage youth after they had been checked by law enforcement, but these effects quickly decayed over time. Establishments that had a close neighbor (within 125 m) checked in the past 90 days were also less likely to sell alcohol to young-appearing buyers. The spatial effect of compliance checks on other establishments decayed rapidly with increasing distance. Results confirm the hypothesis that the effects of police compliance checks do spill over to neighboring establishments. These findings have implications for the development of an optimal schedule of police compliance checks.

  4. Neighboring Group Participation in Solvolysis of Organosulfur and Related Compounds

    Science.gov (United States)

    1985-08-31

    OF REPORT & PERIOD COVERED Neighboring Group Participation in Solvolysis 1 Sep 82 - 31 Aug 85 of Organosulfur and Related Compounds Final Report 6...KEY WORDS (Continue on reveree side It neceeary and Identify by block number) Solvolysis Organosulfur Sulfur Compounds Oxygen Compounds 2 0. A9SrWAcr...Participation in Solvolysis of Organosulfur and Related Compounds Duration of project: September 1, 1982 - August 31, 1985 Personnel: 1) David E. Knox

  5. Applicability of the CALUX bioassay for screening of dioxin levels in human milk samples

    DEFF Research Database (Denmark)

    Laier, P.; Cederberg, Tommy Licht; Larsen, John Christian

    2003-01-01

    lower REP in CALUX. The total dioxin-like activity was determined in 16 Danish human milk samples and was in the range 20.5-55.8 pg TEQ g(-1) fat. These values were compared with TEQs obtained from GC/MS analysis (range 14.8-43.6 pg TEQ-g(-1) fat) that overall were a little lower than CALUX TEQs...... and applied for monitoring levels of dioxins in human milk samples. Combination effects of dioxin-like compounds were evaluated by testing potential mechanisms of interaction between seven of the major dioxin-like compounds in human milk using the isobole method. Results showed that the compounds acted....... The results obtained with the bioassay when testing milk extracts fractionated into dioxins/furans, non-ortho PCB and mono/di-ortho PCB fractions indicated that the correlation between the bioassay and the chemical analyses depends primarily on the A receptor activity observed in the mono/di-ortho PCB...

  6. Applicability of the CALUX bioassay for screening of dioxin levels in human milk samples

    DEFF Research Database (Denmark)

    Laier, P.; Cederberg, Tommy Licht; Larsen, John Christian

    2003-01-01

    and applied for monitoring levels of dioxins in human milk samples. Combination effects of dioxin-like compounds were evaluated by testing potential mechanisms of interaction between seven of the major dioxin-like compounds in human milk using the isobole method. Results showed that the compounds acted...... lower REP in CALUX. The total dioxin-like activity was determined in 16 Danish human milk samples and was in the range 20.5-55.8 pg TEQ g(-1) fat. These values were compared with TEQs obtained from GC/MS analysis (range 14.8-43.6 pg TEQ-g(-1) fat) that overall were a little lower than CALUX TEQs....... The results obtained with the bioassay when testing milk extracts fractionated into dioxins/furans, non-ortho PCB and mono/di-ortho PCB fractions indicated that the correlation between the bioassay and the chemical analyses depends primarily on the A receptor activity observed in the mono/di-ortho PCB...

  7. Estimation of uranium in bioassay samples of occupational workers by laser fluorimetry

    International Nuclear Information System (INIS)

    Suja, A.; Prabhu, S.P.; Sawant, P.D.; Sarkar, P.K.; Tiwari, A.K.; Sharma, R.

    2012-01-01

    A newly established uranium processing facility has been commissioned at BARC, Trombay. Monitoring of occupational workers is essential to assess intake of uranium in this facility. A group of 21 workers was selected for bioassay monitoring to assess the existing urinary excretion levels of uranium before the commencement of actual work. Bioassay samples collected from these workers were analyzed by ion-exchange technique followed by laser fluorimetry. Standard addition method was followed for estimation of uranium concentration in the samples. The minimum detectable activity by this technique is about 0.2 ng. The range of uranium observed in these samples varies from 19 to 132 ng/L. Few of these samples were also analyzed by fission track analysis technique and the results were found to be comparable to those obtained by laser fluorimetry. The urinary excretion rate observed for the individual can be regarded as a 'personal baseline' and will be treated as the existing level of uranium in urine for these workers at the facility. (author)

  8. Bioassay of Lake Onego bottom sediments toxicity based on their chemical composition and deepwater macrozoobenthos state

    Directory of Open Access Journals (Sweden)

    Kalinkina Nataliya Michailovna

    2017-03-01

    Full Text Available The bioassay of the toxicity of bottom sediments sampled in different areas of Lake Onega was carried out by crustaceans biotesting (Ceriodaphnia affinis Lillijeborg. It was shown that in the most areas of Lake Onega there are non-toxic bottom sediments. Toxic bottom sediments were found in Kondopogskaya Bay, intensively polluted with pulp-and-paper mill wastewaters. For the first time in the deep central part of Lake Onega the area was revealed where the toxic bottom sediments contain a high content of iron, manganese and other trace elements typical for the central areas of the lake. The mapping of the bottom of Lake Onega was accomplished, and three zones were identified based on the analysis of the data concerning the chemical composition of bottom sediments, bioassay toxicity data and the results of the deepwater macrozoobenthos assessment. For each zone the parameters of the main groups of benthos (Amphipoda, Oligochaeta, Chironomidae were defined. The first zone is located in the area of intensive anthropogenic influence (Kondopogskaya Bay, Petrozavodskaya Bay, Povenets Bay, Kizhi Skerries. The second zone is located mostly in the deep part of Petrozavodskaya Bay, where the most intensive development of amphipods is observed. The third area is identified for the first time: it is located in the central deep part of Lake Onega, where the communities of macrozoobenthos are limited by a natural toxic factor.

  9. Bioassay-guided purification and identification of PPARalpha/gamma agonists from Chlorella sorokiniana.

    Science.gov (United States)

    Chou, Yu-Cheng; Prakash, Ekambaranellore; Huang, Chien-Fu; Lien, Tzu-Wen; Chen, Xin; Su, Ih-Jen; Chao, Yu-Sheng; Hsieh, Hsing-Pang; Hsu, John Tsu-An

    2008-05-01

    This study isolated agonists of peroxisome proliferator activated receptors (PPARs) from the green algae Chlorella sorokiniana, using a bioassay-guided purification strategy. PPARs are widely recognized as the molecular drug targets for many diseases including hyperglycemia, diabetes, obesity and cancer. Two independent bioassays were developed. The first is the scintillation proximity assay, a ligand binding assay. The other is the cell-based transcriptional activation assay which uses the Dual-Luciferase reporter system as the reporter gene under the control of the PPAR response element. Using these two assays, a PPARgamma-active fraction, CE 3-3, was obtained from C. sorokiniana extracts, which was also able to activate PPARalphamediated gene expression. To elucidate the active ingredients in the CE 3-3 fraction, GC-MS analysis was employed. The results showed that the CE 3-3 fraction consisted of at least ten fatty acids (FAs). The bioactivities of several of the individual FAs were evaluated for their PPARgamma activity and the results showed that linolenic acid and linoleic acid were the most potent FAs tested. Our studies indicate that Chlorella sorokiniana could have potential health benefits through the dual activation of PPARalpha/gamma via its unique FA constituents.

  10. Evidence for cultural differences between neighboring chimpanzee communities.

    Science.gov (United States)

    Luncz, Lydia V; Mundry, Roger; Boesch, Christophe

    2012-05-22

    The majority of evidence for cultural behavior in animals has come from comparisons between populations separated by large geographical distances that often inhabit different environments. The difficulty of excluding ecological and genetic variation as potential explanations for observed behaviors has led some researchers to challenge the idea of animal culture. Chimpanzees (Pan troglodytes verus) in the Taï National Park, Côte d'Ivoire, crack Coula edulis nuts using stone and wooden hammers and tree root anvils. In this study, we compare for the first time hammer selection for nut cracking across three neighboring chimpanzee communities that live in the same forest habitat, which reduces the likelihood of ecological variation. Furthermore, the study communities experience frequent dispersal of females at maturity, which eliminates significant genetic variation. We compared key ecological factors, such as hammer availability and nut hardness, between the three neighboring communities and found striking differences in group-specific hammer selection among communities despite similar ecological conditions. Differences were found in the selection of hammer material and hammer size in response to changes in nut resistance over time. Our findings highlight the subtleties of cultural differences in wild chimpanzees and illustrate how cultural knowledge is able to shape behavior, creating differences among neighboring social groups. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. [Galaxy/quasar classification based on nearest neighbor method].

    Science.gov (United States)

    Li, Xiang-Ru; Lu, Yu; Zhou, Jian-Ming; Wang, Yong-Jun

    2011-09-01

    With the wide application of high-quality CCD in celestial spectrum imagery and the implementation of many large sky survey programs (e. g., Sloan Digital Sky Survey (SDSS), Two-degree-Field Galaxy Redshift Survey (2dF), Spectroscopic Survey Telescope (SST), Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) program and Large Synoptic Survey Telescope (LSST) program, etc.), celestial observational data are coming into the world like torrential rain. Therefore, to utilize them effectively and fully, research on automated processing methods for celestial data is imperative. In the present work, we investigated how to recognizing galaxies and quasars from spectra based on nearest neighbor method. Galaxies and quasars are extragalactic objects, they are far away from earth, and their spectra are usually contaminated by various noise. Therefore, it is a typical problem to recognize these two types of spectra in automatic spectra classification. Furthermore, the utilized method, nearest neighbor, is one of the most typical, classic, mature algorithms in pattern recognition and data mining, and often is used as a benchmark in developing novel algorithm. For applicability in practice, it is shown that the recognition ratio of nearest neighbor method (NN) is comparable to the best results reported in the literature based on more complicated methods, and the superiority of NN is that this method does not need to be trained, which is useful in incremental learning and parallel computation in mass spectral data processing. In conclusion, the results in this work are helpful for studying galaxies and quasars spectra classification.

  12. The N400 as a snapshot of interactive processing: evidence from regression analyses of orthographic neighbor and lexical associate effects

    Science.gov (United States)

    Laszlo, Sarah; Federmeier, Kara D.

    2010-01-01

    Linking print with meaning tends to be divided into subprocesses, such as recognition of an input's lexical entry and subsequent access of semantics. However, recent results suggest that the set of semantic features activated by an input is broader than implied by a view wherein access serially follows recognition. EEG was collected from participants who viewed items varying in number and frequency of both orthographic neighbors and lexical associates. Regression analysis of single item ERPs replicated past findings, showing that N400 amplitudes are greater for items with more neighbors, and further revealed that N400 amplitudes increase for items with more lexical associates and with higher frequency neighbors or associates. Together, the data suggest that in the N400 time window semantic features of items broadly related to inputs are active, consistent with models in which semantic access takes place in parallel with stimulus recognition. PMID:20624252

  13. Fluorescent bioassays for toxic metals in milk and yoghurt

    Directory of Open Access Journals (Sweden)

    Siddiki Mohammad Shohel

    2012-10-01

    Full Text Available Abstract Background From a human health viewpoint, contaminated milk and its products could be a source of long-term exposure to toxic metals. Simple, inexpensive, and on-site assays would enable constant monitoring of their contents. Bioassays that can measure toxic metals in milk or yoghurt might reduce the risk. For this purpose, the green fluorescent protein (GFP-tagged trans factors, ArsR-GFP and CadC-GFP, together with their cis elements were used to develop such bioassays. Results ArsR-GFP or CadC-GFP, which binds either toxic metal or DNA fragment including cis element, was directly mixed with cow’s milk or yoghurt within a neutral pH range. The fluorescence of GFP, which is reflected by the association/dissociation ratio between cis element and trans factor, significantly changed with increasing externally added As (III or Cd (II whereas smaller responses to externally added Pb (II and Zn (II were found. Preparation and dilution of whey fraction at low pH were essential to intrinsic zinc quantification using CadC-GFP. Using the extraction procedure and bioassay, intrinsic Zn (II concentrations ranging from 1.4 to 4.8 mg/l for milk brands and from 1.2 to 2.9 mg/kg for yoghurt brands were determined, which correlated to those determined using inductively coupled plasma atomic emission spectroscopy. Conclusions GFP-tagged bacterial trans factors and cis elements can work in the neutralized whole composition and diluted whey fraction of milk and yoghurt. The feature of regulatory elements is advantageous for establishment of simple and rapid assays of toxic metals in dairy products.

  14. Restructuring the syllabus for MD Pharmacology: Retrospection of bioassay

    Directory of Open Access Journals (Sweden)

    Sarita Mulkalwar

    2014-01-01

    Full Text Available Introduction: Career prospects in Pharmacology are witnessing a sea change due to fast and unanticipated development in the field of clinical research. Numerous openings exist now in academia, pharmaceutical industry, Clinical Research Organizations (CRO or as regulatory consultants, experimental pharmacologists, etc. In short, there are various options to choose from, depending on one′s interest. It′s high time we ponder now over the training programme for post-graduate students in Pharmacology. It needs to be revised keeping in mind the job prospects & uniqueness of the MD Pharmacology degree. Aim: To take suggestions of experienced pharmacologists on the present syllabus for MD Pharmacology and their opinion on continuation of Bioassay experiment which is currently an important part of it . Materials and Methods: A structured questionnaire was given to 30 experienced pharmacologists to seek their opinion on MD Pharmacology syllabus & continuation of Bioassay as a part of MD practical. Results: Out of 30 participants, 29 (96.6% did not use their knowledge of Bioassay during their 10 years of post MD career, whether in pharmaceutical industry or in academics. Only 5 of them (16.6% feel that experiment on bioassay should be continued in the current state. 76.7% of them wish it to be modified to a Dose Response Curve ( DRC . 6.71% feel that it should be totally scrapped. All the participants feel the need of revising current MD Pharmacology syllabus. Current syllabus is inclined more towards preparing good academicians but it lacks the proper training for creating good clinical research professionals. Medical writing, writing necessary documents for clinical trials including regulatory documents, writing an article for medical journals, marketing communication, product monograph and patient information of a clinical trial could be incorporated. They should be aware of the regulatory requirements for conducting studies on investigational drugs

  15. Lanthanide-doped upconverting phosphors for bioassay and therapy

    Science.gov (United States)

    Guo, Huichen; Sun, Shiqi

    2012-10-01

    Lanthanide-doped fluorescent materials have gained increasing attention in recent years due to their unique luminescence properties which have led to their use in wide-ranging fields including those of biological applications. Aside from being used as agents for in vivo imaging, lanthanide-doped fluorescent materials also present many advantages for use in bioassays and therapy. In this review, we summarize the applications of lanthanide-doped up-converting phosphors (UCPs) in protein and gene detection, as well as in photodynamic and gene therapy in recent years, and outline their future potential in biological applications. The current report could serve as a reference for researchers in relevant fields.

  16. Estimation of 244Cm intake by bioassay measurements following a contamination incident

    International Nuclear Information System (INIS)

    Thein, M.; Bogard, J.S.; Eckerman, K.F.

    1988-01-01

    An employee was contaminated with radioactive material consisting primarily of 244 Cm and 246 Cm as a consequence of handling a curium nitrate solution at a reprocessing facility. In vivo gamma analysis and in vitro (urine and fecal) analysis were initiated soon after the incident. Further in vivo measurements were performed regularly through hour 528, and in vitro bioassay measurements were obtained through day 74. A sample of the curium solution from the workplace was obtained to confirm that the nitrate was the chemical form and to identify the curium isotopes present. The mass ratio of 244 Cm: 246 Cm was determined to be 91:7. Diethylenetriaminepentaacetate (DTPA) was administered on hours 33 and 71. Observed excretion rates were consistent with available information for curium in the literature. In this paper, the results of the in vivo and in vitro measurements are presented and intake estimates for the incident are developed using various excretion rate functions. 11 refs., 3 figs., 2 tabs

  17. Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Seery, Cliff R. [Institute for Water and Environmental Resource Management, Department of Environmental Sciences, University of Technology, Sydney, Westbourne Street, Gore Hill, 2065 NSW (Australia); Gunthorpe, Leanne [Primary Industries Research Victoria (PIRVic), VIC (Australia); Ralph, Peter J. [Institute for Water and Environmental Resource Management, Department of Environmental Sciences, University of Technology, Sydney, Westbourne Street, Gore Hill, 2065 NSW (Australia)]. E-mail: peter.ralph@uts.edu.au

    2006-03-15

    The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield ({delta}F/Fm') of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC{sub 5}s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC{sub 5}s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6 h, as opposed to more than 50 h for the germination bioassay. - Chlorophyll a fluorescence measurements form the basis of a macroalgal bioassay with many advantages over germination-based methods.

  18. Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays

    International Nuclear Information System (INIS)

    Seery, Cliff R.; Gunthorpe, Leanne; Ralph, Peter J.

    2006-01-01

    The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield (ΔF/Fm') of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC 5 s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC 5 s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6 h, as opposed to more than 50 h for the germination bioassay. - Chlorophyll a fluorescence measurements form the basis of a macroalgal bioassay with many advantages over germination-based methods

  19. Detection of estrogen receptor endocrine disruptor potency of commonly used organochlorine pesticides using the LUMI-CELL ER bioassay

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, J.D.; Chu, A.C.; Clark, G.C. [Xenobiotic Detection Systems, Inc., Durham, NC (United States); Chu, M.D. [Alta Analytical Perspectives, Wilmington, NC (United States); Denison, M.S. [Dept. of Environmental Toxicology, Univ. of California, Davis, CA (United States)

    2004-09-15

    In order to detect the endocrine disrupting potency of organochlorine pesticides and other compounds, BG-1 (human ovarian carcinoma) cells containing a stably transfected estrogenresponsive luciferase reporter gene plasmid (BG1Luc4E2), was used. This cell line, termed the LUMI-CELL trademark ER estrogenic cell bioassay system, responds in a time-, dose dependent- and chemical-specific manner with the induction of luciferase gene expression in response to exposure to estrogen (but not other steroid hormones) and estrogenic chemicals in a high-throughput screening (HTPS) format6. Here we describe studies in which the LUMI-CELL trademark ER estrogenic cell bioassay system was used for high throughput screening (HTPS) analysis of the estrogenic disrupting potency of several commonly used pesticides and organochlorines: p,p'DDT; p,p'-DDE; DDD; {alpha}a-chlordane; {psi}-chlordane; Kepone; Methoxychlor; Vinclozolin; Fenarimol; 2,4,5-Trichlorophenoxyacetic Acid; and Dieldrin. Our results demonstrate the utility of XDS's LUMI-CELL trademark ER bioassay HTPS system for screening chemicals for estrogenic activity.

  20. Discourse analysis and the use of media in the good neighbor policy Análise do Discurso e o uso dos meios de comunicação na Política Externa de Boa Vizinhança.

    Directory of Open Access Journals (Sweden)

    Isaias Albertin Moraes

    2012-05-01

    Full Text Available This article, making use of discourse analysis, sough to cast an eye the use and impacts caused by the media in Brazil Foreign Policy Good Neighbor government of Franklin Delano Roosevelt, President of the United States of America - USA from 1933 to 1945. Carring out a survey to identify the importance and applications of media and cultural instruments in Foreign Policy Good Neighbor, justified and finds its relevance to better use and extensive knowledge of various instruments of International Relations. The media communication and culture, not infrequently, are overlooked in the formulation of foreign policy of states, however, when used strategically, are able to act on the collective and nations, forging lines of influence in a given situation. First, the study sought to give an overview on the key of discourse analysis, using, primarily the studies of Michel Foucault. Later, there was a brief bibliography and history of primary and secondary sources, with a view to presenting the discursive production of the Foreign Policy Good Neighboor and its main guidelines for Latin America, especially to Brazil. The article sought, moreover, synthesize, in the third part of the text, the fundamental premises of the use of the media, essentially, advertising, radio and cinema in addition to its informative character and its entertainment function. Armed with this set of elements, the research brought verify the period in question, the relevance of the communication mechanisms for building values, understandings, ideals and identities. The study concluded, finally, that the cultural aspects, produced by the Foreign Policy Good Neighbor and sold to the other Latin American countries issued lifestyles, concepts, visions and it was one of the first exports of an idealized versions of  American Way of Life.O presente artigo, fazendo uso da Análise do Discurso, buscou lançar um olhar na utilização e nos impactos causados pelos meios de comunicação, no

  1. Compatibility of hydroxypropyl-{beta}-cyclodextrin with algal toxicity bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Fai, Patricia Bi; Grant, Alastair [School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Reid, Brian J. [School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom)], E-mail: b.reid@uea.ac.uk

    2009-01-15

    Numerous reports have indicated that hydrophobic organic compound bioaccessibility in sediment and soil can be determined by extraction using aqueous hydroxypropyl-{beta}-cyclodextrin (HPCD) solutions. This study establishes the compatibility of HPCD with Selenastrum capricornutum and assesses whether its presence influences the toxicity of reference toxicants. Algal growth inhibition (72 h) showed no significant (P > 0.05) difference at HPCD concentrations up to and including 20 mM. HPCD presence did not influence the toxicity of the inorganic reference toxicant (ZnSO{sub 4}), with IC50 values of 0.82 {mu}M and 0.85 {mu}M, in the presence and absence of HPCD (20 mM), respectively. However, HPCD presence (20 mM) reduced the toxicity of 2,4-dichlorophenol and the herbicides diuron and isoproturon. These reductions were attributed to inclusion complex formation between the toxicants and the HPCD cavity. Liberation of complexed toxicants, by sample manipulation prior to toxicity assessment, is proposed to provide a sensitive, high throughput, bioassay that reflects compound bioaccessibility. - Compatibility of the biomimetic HPCD extraction method with algal cell growth inhibition bioassays to assess toxicity of reference toxicants and environmental relevant herbicides.

  2. Progress in herbicide determination with the thylakoid bioassay.

    Science.gov (United States)

    Trapmann, S; Etxebarria, N; Schnabl, H; Grobecker, K H

    1998-01-01

    Chloroplast thylakoids are used as biological units to determine herbicides in different kinds of water samples as well as in aqueous extracts of compost, soil or food samples. The thylakoid bioassay shows clearly inhibition of fluorescence yield in the presence of photosystem II specific herbicides. Due to this method the ecotoxicological effect of samples with unknown pollutants can be tested fast and cost effective. It has been proven that all photosynthetic active compounds are recorded at the same time because only additive interactions occur. Therefore, the contamination level can be expressed as cumulative parameter for photosystem II active substances. Application was improved clearly by the addition of the radical scavenger sodium ascorbate to the isolation media and by a higher concentration of the measuring medium. A new data evaluation method is described yielding in a lower detection limit of 0.4 microg diuron/1. The guidelines for the quality of water for human consumption with an allowable concentration of pesticides in groups is 0,5 microg/1 and can be controlled with the thylakoid bioassay without performing any preconcentration steps.

  3. Query-Adaptive Reciprocal Hash Tables for Nearest Neighbor Search.

    Science.gov (United States)

    Liu, Xianglong; Deng, Cheng; Lang, Bo; Tao, Dacheng; Li, Xuelong

    2016-02-01

    Recent years have witnessed the success of binary hashing techniques in approximate nearest neighbor search. In practice, multiple hash tables are usually built using hashing to cover more desired results in the hit buckets of each table. However, rare work studies the unified approach to constructing multiple informative hash tables using any type of hashing algorithms. Meanwhile, for multiple table search, it also lacks of a generic query-adaptive and fine-grained ranking scheme that can alleviate the binary quantization loss suffered in the standard hashing techniques. To solve the above problems, in this paper, we first regard the table construction as a selection problem over a set of candidate hash functions. With the graph representation of the function set, we propose an efficient solution that sequentially applies normalized dominant set to finding the most informative and independent hash functions for each table. To further reduce the redundancy between tables, we explore the reciprocal hash tables in a boosting manner, where the hash function graph is updated with high weights emphasized on the misclassified neighbor pairs of previous hash tables. To refine the ranking of the retrieved buckets within a certain Hamming radius from the query, we propose a query-adaptive bitwise weighting scheme to enable fine-grained bucket ranking in each hash table, exploiting the discriminative power of its hash functions and their complement for nearest neighbor search. Moreover, we integrate such scheme into the multiple table search using a fast, yet reciprocal table lookup algorithm within the adaptive weighted Hamming radius. In this paper, both the construction method and the query-adaptive search method are general and compatible with different types of hashing algorithms using different feature spaces and/or parameter settings. Our extensive experiments on several large-scale benchmarks demonstrate that the proposed techniques can significantly outperform both

  4. Quality and efficiency in high dimensional Nearest neighbor search

    KAUST Repository

    Tao, Yufei

    2009-01-01

    Nearest neighbor (NN) search in high dimensional space is an important problem in many applications. Ideally, a practical solution (i) should be implementable in a relational database, and (ii) its query cost should grow sub-linearly with the dataset size, regardless of the data and query distributions. Despite the bulk of NN literature, no solution fulfills both requirements, except locality sensitive hashing (LSH). The existing LSH implementations are either rigorous or adhoc. Rigorous-LSH ensures good quality of query results, but requires expensive space and query cost. Although adhoc-LSH is more efficient, it abandons quality control, i.e., the neighbor it outputs can be arbitrarily bad. As a result, currently no method is able to ensure both quality and efficiency simultaneously in practice. Motivated by this, we propose a new access method called the locality sensitive B-tree (LSB-tree) that enables fast highdimensional NN search with excellent quality. The combination of several LSB-trees leads to a structure called the LSB-forest that ensures the same result quality as rigorous-LSH, but reduces its space and query cost dramatically. The LSB-forest also outperforms adhoc-LSH, even though the latter has no quality guarantee. Besides its appealing theoretical properties, the LSB-tree itself also serves as an effective index that consumes linear space, and supports efficient updates. Our extensive experiments confirm that the LSB-tree is faster than (i) the state of the art of exact NN search by two orders of magnitude, and (ii) the best (linear-space) method of approximate retrieval by an order of magnitude, and at the same time, returns neighbors with much better quality. © 2009 ACM.

  5. Role of first-neighbor geometry in the electronic and mechanical properties of atomic contacts

    Science.gov (United States)

    Sabater, C.; Dednam, W.; Calvo, M. R.; Fernández, M. A.; Untiedt, C.; Caturla, M. J.

    2018-02-01

    We study in detail, via experimental measurements, atomistic simulations, and density functional theory transport calculations, the process of formation and the resulting electronic properties of atomic-sized contacts made of Au, Ag, and Cu. Our data analysis of both experimental results and simulations leads to a precise relationship between geometry and electronic transmission—we reestablish the significant influence of the number of first neighbors on the electronic properties of atomic-sized contacts. This result allows us also to interpret subtle differences between the metals during the process of contact formation as well as the characteristics of the resulting contacts.

  6. Grain price spikes and beggar-thy-neighbor policy responses

    DEFF Research Database (Denmark)

    Boysen, Ole; Jensen, Hans Grinsted

    Upward spikes in the international price of food in recent years led some countries to raise export barriers, thereby exacerbating both the price spike and reducing the terms of trade for food-importing countries (beggaring their neighbors). At the same time, and for similar political......-economy reasons, numerous food-importing countries reduced or suspended their import tariffs, and some even provided food import subsidies -- which also exacerbated the international price spike, thus turning the terms of trade even further against food-importing countries. This issue became a major item...

  7. Recognition of Handwritten Character by Fuzzy Neighbor Mesh Feature

    OpenAIRE

    "王,暁文/橋本,禮治"; "/ハシモト, レイジ"; "Wang,Xiaowen/Hashimoto,Reiji"

    1993-01-01

    "The fuzzy mesh feature (FM-feature) which is proposed in our previous work has been proved that it can absorb some handwriting variation. But the recognition rate got there is still not sufficient, one reason of which may be that this feature includes limited structural information about the character. In this work, we consider a modified fuzzy feature of mesh pattern (FNM-feature) by utilizing the neighbor meshes. And by the experiment about that, we have got the result that FNM-feature imp...

  8. Neighboring Structure Visualization on a Grid-based Layout.

    Science.gov (United States)

    Marcou, G; Horvath, D; Varnek, A

    2017-10-01

    Here, we describe an algorithm to visualize chemical structures on a grid-based layout in such a way that similar structures are neighboring. It is based on structure reordering with the help of the Hilbert Schmidt Independence Criterion, representing an empirical estimate of the Hilbert-Schmidt norm of the cross-covariance operator. The method can be applied to any layout of bi- or three-dimensional shape. The approach is demonstrated on a set of dopamine D5 ligands visualized on squared, disk and spherical layouts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. 77 FR 50504 - Good Neighbor Environmental Board Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2012-08-21

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9719-3] Good Neighbor Environmental Board Notification of... Advisory Committee Act, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will hold... with Mexico. Purpose of Meeting: The purpose of this teleconference is to discuss the Good Neighbor...

  10. 78 FR 53755 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2013-08-30

    ... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OA-2013-0124] Good Neighbor Environmental Board... Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will... of Meeting: The purpose of this teleconference is to discuss the Good Neighbor Environmental Board's...

  11. 78 FR 17395 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2013-03-21

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9793-1; EPA-HQ-OA-2013-0124] Good Neighbor Environmental... Federal Advisory Committee Act, Public Law 92- 463, notice is hereby given that the Good Neighbor... discuss the Good Neighbor Environmental Board's Sixteenth Report. The report will focus on environmental...

  12. 77 FR 13599 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2012-03-07

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9644-7] Good Neighbor Environmental Board; Notification of... Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will... with Mexico. Purpose of Meeting: The purpose of this teleconference is to discuss the Good Neighbor...

  13. 75 FR 3730 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2010-01-22

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9105-3] Good Neighbor Environmental Board; Notification of... Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will... approve the Good Neighbor Environmental Board's Thirteenth Report. SUPPLEMENTARY INFORMATION: If you wish...

  14. 77 FR 57083 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2012-09-17

    ... ENVIRONMENTAL PROTECTION AGENCY Good Neighbor Environmental Board; Notification of Public Advisory...- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will hold a public... of Meeting: The purpose of this teleconference is to discuss and approve the Good Neighbor...

  15. 78 FR 29132 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2013-05-17

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9814-6] (EPA-HQ-OA-2013-0124) Good Neighbor Environmental... Advisory Committee Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental... of Meeting: The purpose of each of these teleconferences will be to discuss the Good Neighbor...

  16. 75 FR 5790 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2010-02-04

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9110-5] Good Neighbor Environmental Board; Notification of... Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will... Good Neighbor Environmental Board's Thirteenth Report. SUPPLEMENTARY INFORMATION: If you wish to make...

  17. 78 FR 60280 - Good Neighbor Environmental Board; Cancellation Notice of Public Advisory Committee teleconference

    Science.gov (United States)

    2013-10-01

    ... ENVIRONMENTAL PROTECTION AGENCY [(EPA-HQ-OA-2013-0124) FRL 9901-68-OA] Good Neighbor Environmental... Agency (EPA). ACTION: Cancellation of the Good Neighbor Environmental Board Teleconference. SUMMARY: EPA announced in the Federal Register on May 17, 2013 [FRL- 9814-6] a Good Neighbor Environmental Board (GNEB...

  18. 78 FR 65981 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2013-11-04

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9902-42-OA; EPA-HQ-OA-2013-0124] Good Neighbor Environmental... Advisory Committee Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental... is to discuss the Good Neighbor Environmental Board's Sixteenth Report and preliminary advice letter...

  19. Information Retrieval Document Classified with K-Nearest Neighbor

    Directory of Open Access Journals (Sweden)

    Badruz Zaman

    2016-01-01

    Full Text Available Along with the rapid advancement of technology development led to the amount of information available is also increasingly abundant. The aim of this study was to determine how the implementation of information retrieval system in the classification of the journal by using the cosine similarity and K-Nearest Neighbor (KNN. The data used as many as 160 documents with categories such as Physical Sciences and Engineering, Life Science, Health Science, and Social Sciences and Humanities. Construction stage begins with the use of text mining processing, the weighting of each token by using the term frequency-inverse document frequency (TF-IDF, calculate the degree of similarity of each document by using the cosine similarity and classification using k-Nearest Neighbor.Evaluation is done by using the testing documents as much as 20 documents, with a value of k = {37, 41, 43}. Evaluation system shows the level of success in classifying documents on the value of k = 43 with a value precision of 0501. System test results showed that 20 document testing used can be classified according to the actual category.

  20. Using K-Nearest Neighbor in Optical Character Recognition

    Directory of Open Access Journals (Sweden)

    Veronica Ong

    2016-03-01

    Full Text Available The growth in computer vision technology has aided society with various kinds of tasks. One of these tasks is the ability of recognizing text contained in an image, or usually referred to as Optical Character Recognition (OCR. There are many kinds of algorithms that can be implemented into an OCR. The K-Nearest Neighbor is one such algorithm. This research aims to find out the process behind the OCR mechanism by using K-Nearest Neighbor algorithm; one of the most influential machine learning algorithms. It also aims to find out how precise the algorithm is in an OCR program. To do that, a simple OCR program to classify alphabets of capital letters is made to produce and compare real results. The result of this research yielded a maximum of 76.9% accuracy with 200 training samples per alphabet. A set of reasons are also given as to why the program is able to reach said level of accuracy.

  1. Isotope effects in hydrogen atom transfers. 9. Neighboring group participation

    International Nuclear Information System (INIS)

    Lewis, E.S.; Shen, C.C.

    1977-01-01

    The tritium isotope effects in hydrogen abstraction by bromine atoms from HC(Me) 2 CH 2 X have been measured in the photobromination reaction by a technique which measures the specific activity of the HBr product. At 1 0 C and with the reverse reaction suppressed or irrelevant the values for k/sub H//k/sub T/ are 3.9, 8.2, and 11.6 for X = CH 3 , Cl, and Br, respectively. An isotope effect of 3.5 for X = H was also measured, but the contribution of the reverse reaction was not established. The relatively large isotope effect for X = Br is interpreted in terms of a weakening of the CH bond by neighboring bromine participation. The smaller effect of chlorine may correspond to a minor participation, but the unfavorable inductive effect of the chlorine is also a factor. The case of X = Br is the microscopic reverse of the addition of HBr to 2-methylpropene, and the results are compared with isotope effects in the addition to HBr to olefins. The measurement of isotope effect is, within some described limitations, a convenient and general method for detecting neighboring group participation in hydrogen atom abstractions

  2. Toxicity Appraisal of Untreated Dyeing Industry Wastewater Based on Chemical Characterization and Short Term Bioassays.

    Science.gov (United States)

    Akhtar, Muhammad Furqan; Ashraf, Muhammad; Javeed, Aqeel; Anjum, Aftab Ahmad; Sharif, Ali; Saleem, Ammara; Akhtar, Bushra; Khan, Abdul Muqeet; Altaf, Imran

    2016-04-01

    Characterizing wastewaters only on a chemical basis may be insufficient owing to their complex nature. The purpose of this study was to assess toxicity of textile dyeing wastewater based on analytical techniques and short term toxicity based bioassays. In this study, screening of the fractionated wastewater through GC-MS showed the presence of phenols, phthalic acid derivatives and chlorpyrifos. Metal analysis revealed that chromium, arsenic and mercury were present in amounts higher than the wastewater discharge limits. Textile dyeing wastewater was found to be highly mutagenic in the Ames test. DNA damage in sheep lymphocytes decreased linearly with an increase in the dilution of wastewater. MTT assay showed that 8.3 percent v/v wastewater decreased cell survival percentage to 50 %. It can be concluded from this study that short term toxicity tests such as Ames test, in vitro comet assay, and cytotoxicity assays may serve as useful indicators of wastewater pollution along with their organic and inorganic chemical characterizations.

  3. Guide to the bioassay of uranium at uranium mine-mill facilities

    International Nuclear Information System (INIS)

    1981-01-01

    As a result of occupational exposure, uranium may be taken into the body by inhalation, ingestion or absorption through skin wounds. The organs at risk are the lung, kidney, and bones. Analysis of urine samples for uranium is recommended on a regular monthly basis, before and after a rest period, and it is suggested that a worker be removed from a working area if a level above 300 μg/l is found before a rest period, or 150 μg/l after a rest period. Background information on the development of a bioassay program is given, and a recommended program for uranium mine and mill facilities is included. (L.L.)

  4. Robust Discrimination between Single Gold Nanoparticles and Their Dimers in Aqueous Solution for Ultrasensitive Homogeneous Bioassays

    Directory of Open Access Journals (Sweden)

    Jun Kobayashi

    2015-01-01

    Full Text Available We propose a robust method to distinguish isolated single gold nanoparticles (AuNP monomers and their dimers under Brownian motion, a key for ultrasensitive homogeneous bioassays, including AuNP sandwich assays. To detect dimers and distinguish them from a larger number of monomers in aqueous solution, single-particle polarization microscopy was performed. For the accurate detection of individual particles, the optical anisotropy and rotational diffusion time are measured because a dimer is much more anisotropic than the nearly spherical monomer and the rotational diffusion time of a dimer is four times that of a monomer. By employing an autocorrelation analysis, we defined a measure of distinguishing that simultaneously enables high detection probability and low error probability. The detection platform offers homogeneous DNA hybridization assays and immunoassays at the subpicomolar level.

  5. A Bioassay for Determining Resistance Levels in Tarnished Plant Bug Populations to Neonicotinoid Insecticides

    Science.gov (United States)

    A laboratory bioassay was developed and used to test field populations of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), for resistance development to the neonicitinoid insecticides imidacloprid (Trimax®) and thiamethoxam (Centric®). The bioassay determined LC50 values by feeding...

  6. Profiling animal toxicants by automatically mining public bioassay data: a big data approach for computational toxicology.

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    Full Text Available In vitro bioassays have been developed and are currently being evaluated as potential alternatives to traditional animal toxicity models. Already, the progress of high throughput screening techniques has resulted in an enormous amount of publicly available bioassay data having been generated for a large collection of compounds. When a compound is tested using a collection of various bioassays, all the testing results can be considered as providing a unique bio-profile for this compound, which records the responses induced when the compound interacts with different cellular systems or biological targets. Profiling compounds of environmental or pharmaceutical interest using useful toxicity bioassay data is a promising method to study complex animal toxicity. In this study, we developed an automatic virtual profiling tool to evaluate potential animal toxicants. First, we automatically acquired all PubChem bioassay data for a set of 4,841 compounds with publicly available rat acute toxicity results. Next, we developed a scoring system to evaluate the relevance between these extracted bioassays and animal acute toxicity. Finally, the top ranked bioassays were selected to profile the compounds of interest. The resulting response profiles proved to be useful to prioritize untested compounds for their animal toxicity potentials and form a potential in vitro toxicity testing panel. The protocol developed in this study could be combined with structure-activity approaches and used to explore additional publicly available bioassay datasets for modeling a broader range of animal toxicities.

  7. Combined effects of copper and food on the midge Chironomus riparius in whole sediment bioassays

    NARCIS (Netherlands)

    Haas, de E.M.; Paumen, M.L.; Koelmans, A.A.; Kraak, M.H.S.

    2004-01-01

    Effects observed in whole-sediment bioassays must be seen as the joint effect of all sediment characteristics. In whole-sediment bioassays. however. adverse effects oil test organisms are usually attributed to the presence of contaminants and effects of food are often ignored. The aim of this study

  8. In vivo genotoxicity of furan in F344 rats at cancer bioassay doses

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Wei, E-mail: Wei.Ding@fda.hhs.gov [Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Petibone, Dayton M. [Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Latendresse, John R. [Toxicologic Pathology Associates, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Pearce, Mason G. [Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Muskhelishvili, Levan; White, Gene A. [Toxicologic Pathology Associates, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Chang, Ching-Wei [Division of Personalized Nutrition and Medicine, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Mittelstaedt, Roberta A.; Shaddock, Joseph G.; McDaniel, Lea P. [Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Doerge, Daniel R. [Division of Biochemical Toxicology, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States); Morris, Suzanne M.; Bishop, Michelle E.; Manjanatha, Mugimane G.; Aidoo, Anane; Heflich, Robert H. [Division of Genetic and Molecular Toxicology, US FDA/National Center for Toxicological Research, Jefferson, AR 72079 (United States)

    2012-06-01

    Furan, a potent rodent liver carcinogen, is found in many cooked food items and thus represents a human cancer risk. Mechanisms for furan carcinogenicity were investigated in male F344 rats using the in vivo Comet and micronucleus assays, combined with analysis of histopathological and gene expression changes. In addition, formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII)-sensitive DNA damage was monitored as a measure of oxidative DNA damage. Rats were treated by gavage on four consecutive days with 2, 4, and 8 mg/kg bw furan, doses that were tumorigenic in 2-year cancer bioassays, and with two higher doses, 12 and 16 mg/kg. Rats were killed 3 h after the last dose, a time established as producing maximum levels of DNA damage in livers of furan-treated rats. Liver Comet assays indicated that both DNA strand breaks and oxidized purines and pyrimidines increased in a near-linear dose-responsive fashion, with statistically significant increases detected at cancer bioassay doses. No DNA damage was detected in bone marrow, a non-target tissue for cancer, and peripheral blood micronucleus assays were negative. Histopathological evaluation of liver from furan-exposed animals produced evidence of inflammation, single-cell necrosis, apoptosis, and cell proliferation. In addition, genes related to apoptosis, cell-cycle checkpoints, and DNA-repair were expressed at a slightly lower level in the furan-treated livers. Although a mixed mode of action involving direct DNA binding cannot be ruled out, the data suggest that furan induces cancer in rat livers mainly through a secondary genotoxic mechanism involving oxidative stress, accompanied by inflammation, cell proliferation, and toxicity. -- Highlights: ► Furan is a potent rodent liver carcinogen and represents a human cancer risk. ► Furan induces DNA damage in rat liver at cancer bioassay doses. ► Furan induces oxidative stress, inflammation and cell proliferation in rat liver. ► Expression of

  9. Evaluation of eugenol toxicity in bioassays with test-organisms

    Directory of Open Access Journals (Sweden)

    Juliano Santos Gueretz

    2017-12-01

    Full Text Available ABSTRACT: Fish in both natural and farming conditions are exposed to stress of capture, handling, transport or treatment that provoke low zootechnical performance. Anesthetics like eugenol obtained from clove oil have been used strategically not only in freshwater but also in marine and estuarine fish in order to reduce the stress. Apart from the eugenol indication as anesthetic and its low toxicity for animals, its environment action is not clear. Bioassays or ecotoxicity tests with indicator organisms are used to evaluate the mode of action of the pollutants in the environment. The aim of this study was to test the acute toxicity of eugenol using the microcrustacean Daphnia magna and the bacterium Aliivibrio fischeri, and also its chronic toxicity for the algae Desmodesmus subspicatus. Eugenol in the concentrations of 50, 75 and 100mg L-1 were toxic to tested indicator organisms.

  10. Toxicity assessment using different bioassays and microbial biosensors.

    Science.gov (United States)

    Hassan, Sedky H A; Van Ginkel, Steven W; Hussein, Mohamed A M; Abskharon, Romany; Oh, Sang-Eun

    2016-01-01

    Toxicity assessment of water streams, wastewater, and contaminated sediments, is a very important part of environmental pollution monitoring. Evaluation of biological effects using a rapid, sensitive and cost effective method can indicate specific information on ecotoxicity assessment. Recently, different biological assays for toxicity assessment based on higher and lower organisms such as fish, invertebrates, plants and algal cells, and microbial bioassays have been used. This review focuses on microbial biosensors as an analytical device for environmental, food, and biomedical applications. Different techniques which are commonly used in microbial biosensing include amperometry, potentiometry, conductometry, voltammetry, microbial fuel cells, fluorescence, bioluminescence, and colorimetry. Examples of the use of different microbial biosensors in assessing a variety of environments are summarized. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Bioassay techniques for 55Fe in urine samples

    International Nuclear Information System (INIS)

    Cregan, S.P.; Leon, J.W.; Linauskas, S.H.

    1993-11-01

    Solvent extraction, ion chromatography and several rapid screening methods were developed and evaluated for 55 Fe bioassay applications. Isopropyl ether and TNOA column extractions had radiochemical recoveries exceeding 90%. These were very reproducible with a coefficient of variation less than 5%. Screening techniques investigated included direct counting of ashed urine solids, and Fe(OH) 3 . precipitated from urine. The sensitivities (2-50 Bq/d urine) of the screening methods were usually limited by the effective urine volume that could be counted in a liquid scintillation counter. The reference isopropyl ether and chromatography methods could easily achieve sensitivities well below the 1 Bq/d urine output target. (author). 49 refs., 3 tabs., 5 figs

  12. Comprehensive integration of homogeneous bioassays via centrifugo-pneumatic cascading.

    Science.gov (United States)

    Godino, Neus; Gorkin, Robert; Linares, Ana V; Burger, Robert; Ducrée, Jens

    2013-02-21

    This work for the first time presents the full integration and automation concept for a range of bioassays leveraged by cascading a centrifugo-pneumatic valving scheme to sequentially move several liquids through shared channel segments for multi-step sample preparation into the detection zone. This novel centrifugo-pneumatic liquid handling significantly simplifies system manufacture by obviating the need for complex surface functionalization procedures or hybrid material integration, as it is common in conventional valving methods such as capillary burst valves or sacrificial valves. Based on the centrifugo-pneumatic valving scheme, this work presents a toolkit of operational elements implementing liquid loading/transfer, metering, mixing and sedimentation in a microstructured polymer disc. As a proof of concept for the broad class of homogeneous bioassays, the full integration and automation of a colorimetric nitrate/nitrite test for the detection of clinically relevant nitric oxide (NO) in whole blood is implemented. First, 40 μL of plasma is extracted from a 100 μL sample of human blood, incubated for one hour with the enzymatic mixture (60 μL), and finally reacted with 100 μL of colorimetric (Greiss) reagents. Following just a single loading phase at the beginning of the process, all of these steps are automated through the centrifugo-pneumatic cascade with a high level of flow control and synchronization. Our system shows good correlation with controls up to 50 μM of nitrate, which adequately covers the healthy human range (4 to 45.3 μM).

  13. Designing lattice structures with maximal nearest-neighbor entanglement

    International Nuclear Information System (INIS)

    Navarro-Munoz, J C; Lopez-Sandoval, R; Garcia, M E

    2009-01-01

    In this paper, we study the numerical optimization of nearest-neighbor concurrence of bipartite one- and two-dimensional lattices, as well as non-bipartite two-dimensional lattices. These systems are described in the framework of a tight-binding Hamiltonian while the optimization of concurrence was performed using genetic algorithms. Our results show that the concurrence of the optimized lattice structures is considerably higher than that of non-optimized systems. In the case of one-dimensional chains, the concurrence increases dramatically when the system begins to dimerize, i.e., it undergoes a structural phase transition (Peierls distortion). This result is consistent with the idea that entanglement is maximal or shows a singularity near quantum phase transitions. Moreover, the optimization of concurrence in two-dimensional bipartite and non-bipartite lattices is achieved when the structures break into smaller subsystems, which are arranged in geometrically distinguishable configurations.

  14. Radiative energy loss of neighboring subjets arXiv

    CERN Document Server

    Mehtar-Tani, Yacine

    We compute the in-medium energy loss probability distribution of two neighboring subjets at leading order, in the large-$N_c$ approximation. Our result exhibits a gradual onset of color decoherence of the system and accounts for two expected limiting cases. When the angular separation is smaller than the characteristic angle for medium-induced radiation, the two-pronged substructure lose energy coherently as a single color charge, namely that of the parent parton. At large angular separation the two subjets lose energy independently. Our result is a first step towards quantifying effects of energy loss as a result of the fluctuation of the multi-parton jet substructure and therefore goes beyond the standard approach to jet quenching based on single parton energy loss. We briefly discuss applications to jet observables in heavy-ion collisions.

  15. Implementation of Nearest Neighbor using HSV to Identify Skin Disease

    Science.gov (United States)

    Gerhana, Y. A.; Zulfikar, W. B.; Ramdani, A. H.; Ramdhani, M. A.

    2018-01-01

    Today, Android is one of the most widely used operating system in the world. Most of android device has a camera that could capture an image, this feature could be optimized to identify skin disease. The disease is one of health problem caused by bacterium, fungi, and virus. The symptoms of skin disease usually visible. In this work, the symptoms that captured as image contains HSV in every pixel of the image. HSV can extracted and then calculate to earn euclidean value. The value compared using nearest neighbor algorithm to discover closer value between image testing and image training to get highest value that decide class label or type of skin disease. The testing result show that 166 of 200 or about 80% is accurate. There are some reasons that influence the result of classification model like number of image training and quality of android device’s camera.

  16. Young fire ant workers feign death and survive aggressive neighbors

    Science.gov (United States)

    Cassill, Deby L.; Vo, Kim; Becker, Brandie

    2008-07-01

    Feigning death is a method of self-defense employed among a wide range of prey species when threatened by predator species. This paper reports on death-feigning behavior by the fire ant, Solenopsis invicta, during intraspecific aggression among neighboring fire ant workers. Days-old workers responded to aggression by death feigning, weeks-old workers responded by fleeing and months-old workers responded by fighting back. By feigning death, days-old workers were four times more likely to survive aggression than older workers. From a proximate perspective, retaliation by young workers against aggressive older workers is certain to fail. With their relatively soft exoskeleton, young workers would be prone to injury and death and unable to execute an effective attack of biting or stinging older workers with harder exoskeletons. From an ultimate perspective, death feigning allows young workers to survive and contribute to brood care and colony growth, both of which are essential to queen survival and fitness.

  17. Voice activity detection algorithm using perceptual wavelet entropy neighbor slope.

    Science.gov (United States)

    Lee, Gihyoun; Na, Sung Dae; Cho, Jin-Ho; Kim, Myoung Nam

    2014-01-01

    This paper presents a voice activity detection (VAD) approach using a perceptual wavelet entropy neighbor slope (PWENS) in a low signal-to-noise (SNR) environment and with a variety of noise types. The basis for our study is to use acoustic features that have large entropy variance for each wavelet critical band. The speech signal is decomposed by the proposed perceptual wavelet packet decomposition (PWPD), and the VAD function is extracted by PWENS. Finally, VAD is decided by the proposed VAD decision rule using two memory buffers. In order to evaluate the performance of the VAD decision, many speech samples and a variety of SNR conditions were used in the experiment. The performance of the VAD decision is confirmed using objective indexes such as a graph of the VAD decision and the relative error rate.

  18. Enhanced Approximate Nearest Neighbor via Local Area Focused Search.

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, Antonio [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Blazier, Nicholas Paul [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    Approximate Nearest Neighbor (ANN) algorithms are increasingly important in machine learning, data mining, and image processing applications. There is a large family of space- partitioning ANN algorithms, such as randomized KD-Trees, that work well in practice but are limited by an exponential increase in similarity comparisons required to optimize recall. Additionally, they only support a small set of similarity metrics. We present Local Area Fo- cused Search (LAFS), a method that enhances the way queries are performed using an existing ANN index. Instead of a single query, LAFS performs a number of smaller (fewer similarity comparisons) queries and focuses on a local neighborhood which is refined as candidates are identified. We show that our technique improves performance on several well known datasets and is easily extended to general similarity metrics using kernel projection techniques.

  19. Designing lattice structures with maximal nearest-neighbor entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Munoz, J C; Lopez-Sandoval, R [Instituto Potosino de Investigacion CientIfica y Tecnologica, Camino a la presa San Jose 2055, 78216 San Luis Potosi (Mexico); Garcia, M E [Theoretische Physik, FB 18, Universitaet Kassel and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Str.40, 34132 Kassel (Germany)

    2009-08-07

    In this paper, we study the numerical optimization of nearest-neighbor concurrence of bipartite one- and two-dimensional lattices, as well as non-bipartite two-dimensional lattices. These systems are described in the framework of a tight-binding Hamiltonian while the optimization of concurrence was performed using genetic algorithms. Our results show that the concurrence of the optimized lattice structures is considerably higher than that of non-optimized systems. In the case of one-dimensional chains, the concurrence increases dramatically when the system begins to dimerize, i.e., it undergoes a structural phase transition (Peierls distortion). This result is consistent with the idea that entanglement is maximal or shows a singularity near quantum phase transitions. Moreover, the optimization of concurrence in two-dimensional bipartite and non-bipartite lattices is achieved when the structures break into smaller subsystems, which are arranged in geometrically distinguishable configurations.

  20. Radionuclide content of an exhumed canyon vessel and neighboring soil

    International Nuclear Information System (INIS)

    Holcomb, H.P.

    1976-11-01

    The long-term hazard potential associated with burial of process equipment from radiochemical separations plants is being evaluated. As part of this evaluation, a feed adjustment tank was exhumed eighteen years after burial. The tank had been in service in the fuel reprocessing plant for twenty-nine months before it was retired. Assay of the exhumed tank indicated that 7 mg (0.4 mCi) of 239 Pu and 1 mCi of 137 Cs remained on its surfaces; 1.1 mg (0.07 mCi) 239 Pu, 0.4 mCi 137 Cs, and 3.5 mCi 90 Sr were found in neighboring soil. The vessel and surrounding soil have met the present guidelines (less than or equal to 10 nCi/g) of the U. S. Energy Research and Development Administration (ERDA) for nonretrievable waste

  1. Introduction to machine learning: k-nearest neighbors.

    Science.gov (United States)

    Zhang, Zhongheng

    2016-06-01

    Machine learning techniques have been widely used in many scientific fields, but its use in medical literature is limited partly because of technical difficulties. k-nearest neighbors (kNN) is a simple method of machine learning. The article introduces some basic ideas underlying the kNN algorithm, and then focuses on how to perform kNN modeling with R. The dataset should be prepared before running the knn() function in R. After prediction of outcome with kNN algorithm, the diagnostic performance of the model should be checked. Average accuracy is the mostly widely used statistic to reflect the kNN algorithm. Factors such as k value, distance calculation and choice of appropriate predictors all have significant impact on the model performance.

  2. Reduction of Conflicts in Mining Development Using "Good Neighbor Agreements"

    Science.gov (United States)

    Masaitis, A.

    2013-05-01

    New environmental and social challenges for the mining industry in both developed and developing countries show the obvious need to implement "responsible" mining practices that include improved community involvement. Good Neighbor Agreements (GNA's) are a relatively new mechanism for improving communication and trust between a mining company and the community. The focus of a GNA will be to provide a written and enforceable agreement, negotiated between the concerned public and the respective mining company to respond to concerns from the public, and also provide a mechanism for conflict resolution, when there is mutual benefit to maintain a working relationship. Development of GNA's, a recently evolving process that promotes environmentally sound relationships between mines and the surrounding communities. Modify and apply the resulting GNA formulas to the developing countries and countries with transitional economies. This is particularly important for countries that have poorly functioning regulatory systems that cannot guarantee a healthy and safe environment for the communities. The fundamental questions addressed by this research. 1. This is a three-year research project started in August 2012 at the University of Nevada, Reno (UNR) to develop a Good Neighbor Agreements standards as well as to investigate the details of mine development. 2. Identify spheres of possible cooperation between mining companies, government organizations, and the Non-Governmental Organizations (NGO's). Use this cooperation to develop international standards for the GNA, to promote exchange of environmental information, and exchange of successful environmental, health, and safety practices between mining operations from different countries. Discussion: The Good Neighbor Agreement currently evolving will address the following: 1. Provide an economically viable mechanism for developing a partnership between mining operations and the local communities that will increase mining industry

  3. A novel bioassay for the activity determination of therapeutic human brain natriuretic peptide (BNP.

    Directory of Open Access Journals (Sweden)

    Lei Yu

    Full Text Available BACKGROUND: Recombinant human brain natriuretic peptide (rhBNP is an important peptide-based therapeutic drug indicated for the treatment of acute heart failure. Accurate determination of the potency of therapeutic rhBNP is crucial for the safety and efficacy of the drug. The current bioassay involves use of rabbit aortic strips, with experiments being complicated and time-consuming and markedly variable in results. Animal-less methods with better precision and accuracy should be explored. We have therefore developed an alternative cell-based assay, which relies on the ability of BNP to induce cGMP production in HEK293 cells expressing BNP receptor guanylyl cyclase-A. METHODOLOGY/PRINCIPAL FINDINGS: An alternative assay based on the measurement of BNP-induced cGMP production was developed. Specifically, the bioassay employs cells engineered to express BNP receptor guanylyl cyclase-A (GCA. Upon rhBNP stimulation, the levels of the second messager cGMP in these cells drastically increased and subsequently secreted into culture supernatants. The quantity of cGMP, which corresponds to the rhBNP activity, was determined using a competitive ELISA developed by us. Compared with the traditional assay, the novel cell-based assay demonstrated better reproducibility and precision. CONCLUSION/SIGNIFICANCE: The optimized cell-based assay is much simpler, more rapid and precise compared with the traditional assay using animal tissues. To our knowledge, this is the first report on a novel and viable alternative assay for rhBNP potency analysis.

  4. A New Neighboring Pixels Method for Reducing Aerosol Effects on the NDVI Images

    Directory of Open Access Journals (Sweden)

    Dandan Wang

    2016-06-01

    Full Text Available A new algorithm was developed in this research to minimize aerosol effects on the normalized difference vegetation index (NDVI. Simulation results show that in red-NIR reflectance space, variations in red and NIR channels to aerosol optical depth (AOD follow a specific pattern. Based on this rational, the apparent reflectance in these two bands of neighboring pixels were used to reduce aerosol effects on NDVI values of the central pixel. We call this method the neighboring pixels (NP algorithm. Validation was performed over vegetated regions in the border area between China and Russia using Landsat 8 Operational Land Imager (OLI imagery. Results reveal good agreement between the aerosol corrected NDVI using our algorithm and that derived from the Landsat 8 surface reflectance products. The accuracy is related to the gradient of NDVI variation. This algorithm can achieve high accuracy in homogeneous forest or cropland with the root mean square error (RMSE being equal to 0.046 and 0.049, respectively. This algorithm can also be applied to atmospheric correction and does not require any information about atmospheric conditions. The use of the moving window analysis technique reduces errors caused by the spatial heterogeneity of aerosols. Detections of regions with homogeneous NDVI are the primary sources of biases. This new method is operational and can prove useful at different aerosol concentration levels. In the future, this approach may also be used to examine other indexes composed of bands attenuated by noises in remote sensing.

  5. Carbon-hydrogen defects with a neighboring oxygen atom in n-type Si

    Science.gov (United States)

    Gwozdz, K.; Stübner, R.; Kolkovsky, Vl.; Weber, J.

    2017-07-01

    We report on the electrical activation of neutral carbon-oxygen complexes in Si by wet-chemical etching at room temperature. Two deep levels, E65 and E75, are observed by deep level transient spectroscopy in n-type Czochralski Si. The activation enthalpies of E65 and E75 are obtained as EC-0.11 eV (E65) and EC-0.13 eV (E75). The electric field dependence of their emission rates relates both levels to single acceptor states. From the analysis of the depth profiles, we conclude that the levels belong to two different defects, which contain only one hydrogen atom. A configuration is proposed, where the CH1BC defect, with hydrogen in the bond-centered position between neighboring C and Si atoms, is disturbed by interstitial oxygen in the second nearest neighbor position to substitutional carbon. The significant reduction of the CH1BC concentration in samples with high oxygen concentrations limits the use of this defect for the determination of low concentrations of substitutional carbon in Si samples.

  6. Comparison of solid and liquid-phase bioassays using ecoscores to assess contaminated soils

    International Nuclear Information System (INIS)

    Lors, Christine; Ponge, Jean-Francois; Martinez Aldaya, Maite; Damidot, Denis

    2011-01-01

    Bioassays on aqueous and solid phases of contaminated soils were compared, belonging to a wide array of trophic and response levels and using ecoscores for evaluating ecotoxicological and genotoxicological endpoints. The method was applied to four coke factory soils contaminated mainly with PAHs, but also to a lesser extent by heavy metals and cyanides. Aquatic bioassays do not differ from terrestrial bioassays when scaling soils according to toxicity but they are complementary from the viewpoint of ecological relevance. Both aquatic and terrestrial endpoints are strongly correlated with concentrations of 3-ring PAHs. This evaluation procedure allows us to propose a cost-effective battery which embraces a wide array of test organisms and response levels: it includes two rapid bioassays (Microtox) and springtail avoidance), a micronucleus test and three bioassays of a longer duration (algal growth, lettuce germination and springtail reproduction). This battery can be recommended for a cost-effective assessment of polluted/remediated soils. - Highlights: → Comparison of liquid- and solid-phase bioassays on contaminated soils, using ecoscores. → Complementarity of liquid- and solid-phase bioassays for the evaluation of environmental hazards. → Proposal for a restricted battery of 5 most sensitive tests. → Use of this restricted battery for a cost-effective assessment of polluted/remediated soils. - Aqueous and solid phases of contaminated soils give similar results in terms of toxicity but are complementary for the evaluation of environmental hazards by ecoscores.

  7. Unwanted Behaviors and Nuisance Behaviors Among Neighbors in a Belgian Community Sample.

    Science.gov (United States)

    Michaux, Emilie; Groenen, Anne; Uzieblo, Katarzyna

    2015-06-30

    Unwanted behaviors between (ex-)intimates have been extensively studied, while those behaviors within other contexts such as neighbors have received much less scientific consideration. Research indicates that residents are likely to encounter problem behaviors from their neighbors. Besides the lack of clarity in the conceptualization of problem behaviors among neighbors, little is known on which types of behaviors characterize neighbor problems. In this study, the occurrence of two types of problem behaviors encountered by neighbors was explored within a Belgian community sample: unwanted behaviors such as threats and neighbor nuisance issues such as noise nuisance. By clearly distinguishing those two types of behaviors, this study aimed at contributing to the conceptualization of neighbor problems. Next, the coping strategies used to deal with the neighbor problems were investigated. Our results indicated that unwanted behaviors were more frequently encountered by residents compared with nuisance problems. Four out of 10 respondents reported both unwanted pursuit behavior and nuisance problems. It was especially unlikely to encounter nuisance problems in isolation of unwanted pursuit behaviors. While different coping styles (avoiding the neighbor, confronting the neighbor, and enlisting help from others) were equally used by the stalked participants, none of them was perceived as being more effective in reducing the stalking behaviors. Strikingly, despite being aware of specialized help services such as community mediation services, only a very small subgroup enlisted this kind of professional help. © The Author(s) 2015.

  8. Review of literature on bioassay methods for estimating radionuclides in urine

    International Nuclear Information System (INIS)

    Prasad, M.V.R.; Surya Narayana, D.S.; Jeevanram, R.K.; Sundarajan, A.R.

    1991-01-01

    Bioassay methods of certain important radionuclides encountered in the nuclear fuel cycle operations, viz., thorium, uranium, sup(239)Pu, sup(241)Am, sup(90)Sr, sup(99)Tc, sup(106)Ru, sup(137)Cs are reviewed, with special emphasis on urinalysis. Since the preconcentration is an important prerequisite for bioassay, various preconcentration methods are also discussed. Brief account of various instruments both nuclear and analytical used in the bioassay programme is included. The sensitivities of the methods cited in the literature vis-a-vis the derived recording levels indicated in ICRP recommendations are compared. Literature surveyed up to 1990 is tabulated. (author). 96 refs., 1 fig ., 3 tabs

  9. Assessment of mobility and bioavailability of contaminants in MSW incineration ash with aquatic and terrestrial bioassays.

    Science.gov (United States)

    Ribé, V; Nehrenheim, E; Odlare, M

    2014-10-01

    Incineration of municipal solid waste (MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction as well as a source of renewable energy. In the process fly and bottom ash is generated as a waste material. The ash residue may vary greatly in composition depending on the type of waste incinerated and it can contain elevated levels of harmful contaminants such as heavy metals. In this study, the ecotoxicity of a weathered, untreated incineration bottom ash was characterized as defined by the H14 criterion of the EU Waste Framework Directive by means of an elemental analysis, leaching tests followed by a chemical analysis and a combination of aquatic and solid-phase bioassays. The experiments were conducted to assess the mobility and bioavailability of ash contaminants. A combination of aquatic and terrestrial bioassays was used to determine potentially adverse acute effects of exposure to the solid ash and aqueous ash leachates. The results from the study showed that the bottom ash from a municipal waste incineration plant in mid-Sweden contained levels of metals such as Cu, Pb and Zn, which exceeded the Swedish EPA limit values for inert wastes. The chemical analysis of the ash leachates showed high concentrations of particularly Cr. The leachate concentration of Cr exceeded the limit value for L/S 10 leaching for inert wastes. Filtration of leachates prior to analysis may have underestimated the leachability of complex-forming metals such as Cu and Pb. The germination test of solid ash and ash leachates using T. repens showed a higher inhibition of seedling emergence of seeds exposed to the solid ash than the seeds exposed to ash leachates. This indicated a relatively low mobility of toxicants from the solid ash into the leachates, although some metals exceeded the L/S 10 leaching limit values for inert wastes. The Microtox® toxicity test showed only a very low toxic response to the ash leachate exposure, while the D. magna

  10. Development and characteristics of an adhesion bioassay for ectocarpoid algae.

    Science.gov (United States)

    Evariste, Emmanuelle; Gachon, Claire M M; Callow, Maureen E; Callow, James A

    2012-01-01

    Species of filamentous brown algae in the family Ectocarpaceae are significant members of fouling communities. However, there are few systematic studies on the influence of surface physico-chemical properties on their adhesion. In the present paper the development of a novel, laboratory-based adhesion bioassay for ectocarpoid algae, at an appropriate scale for the screening of sets of experimental samples in well-replicated and controlled experiments is described. The assays are based on the colonization of surfaces from a starting inoculum consisting of multicellular filaments obtained by blending the cultured alga Ectocarpus crouaniorum. The adhesion strength of the biomass after 14 days growth was assessed by applying a hydrodynamic shear stress. Results from adhesion tests on a set of standard surfaces showed that E. crouaniorum adhered more weakly to the amphiphilic Intersleek® 900 than to the more hydrophobic Intersleek® 700 and Silastic® T2 coatings. Adhesion to hydrophilic glass was also weak. Similar results were obtained for other cultivated species of Ectocarpus but differed from those obtained with the related ectocarpoid species Hincksia secunda. The response of the ectocarpoid algae to the surfaces was also compared to that for the green alga, Ulva.

  11. Evaluation of biotoxicity of textile dyes using two bioassays.

    Science.gov (United States)

    Moawad, Hassan; El-Rahim, Wafaa M Abd; Khalafallah, M

    2003-01-01

    The toxicity of eight textile dyes was evaluated using two bioassays namely: Ames test and seed germination test. The Ames test is widely used for the evaluation of hazardous mutagenic effect of different chemicals, as a short-term screening test for environmental impact assessment. The eight-textile dyes and Eithidium bromide dye (as positive control) were tested with five "his" Salmonella typhimurium strains: TA 100; TA 98; TA 1535; TA 1537; TA 1538. Using six concentrations of each dye (2.5 microg/ml, 4.5 microg/ml, 9 microg/ml, 13.5 microg/ml, 18 microg/ml, and 22.5 microg/ml) revealed that, most of the dyes were mutagenic for the test strains used in this study. The high concentrations of dye eliminated microbial colonies due to the high frequency of mutation causing lethal effect on the cells. In this work the phytotoxicity of different soluble textile dyes was estimated by measuring the relative changes in seed germination of four plants: clover, wheat, tomato and lettuce. The changes in shooting percentages and root length as affected by dye were also measured. Seed germination percent and shoot growth as well as root length were recorded after 6 days of exposure to different concentrations of textile dyes in irrigation water. The results show that high concentrations of dyes were more toxic to seed germination as compared with the lower concentrations. However, the low concentrations of the tested dyes adversely affected the shooting percent significantly.

  12. Analyzing bioassay data using Bayesian methods-A primer

    International Nuclear Information System (INIS)

    Miller, G.; Inkret, W.C.; Schillaci, M.E.

    1997-01-01

    The classical statistics approach used in health physics for the interpretation of measurements is deficient in that it does not allow for the consideration of needle in a haystack effects, where events that are rare in a population are being detected. In fact, this is often the case in health physics measurements, and the false positive fraction is often very large using the prescriptions of classical statistics. Bayesian statistics provides an objective methodology to ensure acceptably small false positive fractions. The authors present the basic methodology and a heuristic discussion. Examples are given using numerically generated and real bioassay data (Tritium). Various analytical models are used to fit the prior probability distribution, in order to test the sensitivity to choice of model. Parametric studies show that the normalized Bayesian decision level k α -L c /σ 0 , where σ 0 is the measurement uncertainty for zero true amount, is usually in the range from 3 to 5 depending on the true positive rate. Four times σ 0 rather than approximately two times σ 0 , as in classical statistics, would often seem a better choice for the decision level

  13. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Anstey, Mitchell R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Fruetel, Julia A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Foster, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hayden, Carl C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Buckley, Heather L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Arnold, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  14. K-nearest neighbors based methods for identification of different gear crack levels under different motor speeds and loads: Revisited

    Science.gov (United States)

    Wang, Dong

    2016-03-01

    features, some other popular statistical models including linear discriminant analysis, quadratic discriminant analysis, classification and regression tree and naive Bayes classifier, are compared with the developed method. The results show that the developed method has the highest prediction accuracies among these statistical models. Additionally, selection of the number of new significant features and parameter selection of K-nearest neighbors are thoroughly investigated.

  15. Unsynchronized influenza epidemics in two neighboring subtropical cities

    Directory of Open Access Journals (Sweden)

    Xiujuan Tang

    2018-04-01

    Full Text Available Objective: The aim of this study was to examine the synchrony of influenza epidemics between Hong Kong and Shenzhen, two neighboring subtropical cities in South China. Methods: Laboratory-confirmed influenza data for the period January 2006 to December 2016 were obtained from the Shenzhen Center for Disease Control and Prevention and the Department of Health in Hong Kong. The population data were retrieved from the 2011 population censuses. The weekly rates of laboratory-confirmed influenza cases were compared between Shenzhen and Hong Kong. Results: Unsynchronized influenza epidemics between Hong Kong and Shenzhen were frequently observed during the study period. Influenza A/H1N1 caused a more severe pandemic in Hong Kong in 2009, but the subsequent seasonal epidemics showed similar magnitudes in both cities. Two influenza A/H3N2 dominant epidemic waves were seen in Hong Kong in 2015, but these epidemics were very minor in Shenzhen. More influenza B epidemics occurred in Shenzhen than in Hong Kong. Conclusions: Influenza epidemics appeared to be unsynchronized between Hong Kong and Shenzhen most of the time. Given the close geographical locations of these two cities, this could be due to the strikingly different age structures of their populations. Keywords: Influenza epidemics, Synchrony, Shenzhen, Hong Kong

  16. Identification of influential users by neighbors in online social networks

    Science.gov (United States)

    Sheikhahmadi, Amir; Nematbakhsh, Mohammad Ali; Zareie, Ahmad

    2017-11-01

    Identification and ranking of influential users in social networks for the sake of news spreading and advertising has recently become an attractive field of research. Given the large number of users in social networks and also the various relations that exist among them, providing an effective method to identify influential users has been gradually considered as an essential factor. In most of the already-provided methods, those users who are located in an appropriate structural position of the network are regarded as influential users. These methods do not usually pay attention to the interactions among users, and also consider those relations as being binary in nature. This paper, therefore, proposes a new method to identify influential users in a social network by considering those interactions that exist among the users. Since users tend to act within the frame of communities, the network is initially divided into different communities. Then the amount of interaction among users is used as a parameter to set the weight of relations existing within the network. Afterward, by determining the neighbors' role for each user, a two-level method is proposed for both detecting users' influence and also ranking them. Simulation and experimental results on twitter data shows that those users who are selected by the proposed method, comparing to other existing ones, are distributed in a more appropriate distance. Moreover, the proposed method outperforms the other ones in terms of both the influential speed and capacity of the users it selects.

  17. Symmetric Link Key Management for Secure Neighbor Discovery in a Decentralized Wireless Sensor Network

    Science.gov (United States)

    2017-09-01

    DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words ) Wireless sensor networks provide a low-signature communications system that can be used for a... serve as the basis for our research. Then, we review existing research in key management for secure neighbor discovery. A. NEIGHBOR DISCOVERY...against Common Forms of Attack Our research served as a proof-of-concept for our key management scheme as applied to neighbor discovery; however, the

  18. Mathematical Model Developed for Environmental Samples: Prediction of GC/MS Dioxin TEQ from XDS-CALUX Bioassay Data

    Science.gov (United States)

    Brown, David J.; Orelien, Jean; Gordon, John D.; Chu, Andrew C.; Chu, Michael D.; Nakamura, Masafumi; Handa, Hiroshi; Kayama, Fujio; Denison, Michael S.; Clark, George C.

    2010-01-01

    Remediation of hazardous waste sites requires efficient and cost-effective methods to assess the extent of contamination by toxic substances including dioxin-like chemicals. Traditionally, dioxin-like contamination has been assessed by gas chromatography/high-resolution mass spectrometry (GC/MS) analysis for specific polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyl congeners. Toxic equivalency factors for these congeners are then used to estimate the overall dioxin toxic equivalency (TEQ) of complex mixtures found in samples. The XDS-CALUX bioassay estimates contamination by dioxin-like chemicals in a sample extract by measuring expression of a sensitive reporter gene in genetically engineered cells. The output of the XDS-CALUX assay is a CALUX-TEQ value, calibrated based on TCDD standards. Soil samples taken from a variety of hazardous waste sites were measured using the XDS-CALUX bioassay and GC/MS. TEQ and CALUX-TEQ from these methods were compared, and a mathematical model was developed describing the relationship between these two data sets: log(TEQ) = 0.654 × log(CALUX-TEQ) + 0.058-(log(CALUX-TEQ))2. Applying this equation to these samples showed that predicted and GC/MS measured TEQ values strongly correlate (R2 = 0.876) and that TEQ values predicted from CALUX-TEQ were on average nearly identical to the GC/MS-TEQ. The ability of XDS-CALUX bioassay data to predict GC/MS-derived TEQ data should make this procedure useful in risk assessment and management decisions. PMID:17626436

  19. Integration of laboratory bioassays into the risk-based corrective action process

    International Nuclear Information System (INIS)

    Edwards, D.; Messina, F.; Clark, J.

    1995-01-01

    Recent data generated by the Gas Research Institute (GRI) and others indicate that residual hydrocarbon may be bound/sequestered in soil such that it is unavailable for microbial degradation, and thus possibly not bioavailable to human/ecological receptors. A reduction in bioavailability would directly equate to reduced exposure and, therefore, potentially less-conservative risk-based cleanup soil goals. Laboratory bioassays which measure bioavailability/toxicity can be cost-effectively integrated into the risk-based corrective action process. However, in order to maximize the cost-effective application of bioassays several site-specific parameters should be addressed up front. This paper discusses (1) the evaluation of parameters impacting the application of bioassays to soils contaminated with metals and/or petroleum hydrocarbons and (2) the cost-effective integration of bioassays into a tiered ASTM type framework for risk-based corrective action

  20. Phototoxicity activity of Psoralea drupacea L. using Atremia salina bioassay system

    Directory of Open Access Journals (Sweden)

    Mohammad Ramezani

    2011-07-01

    Conclusion: The result showed that P. drupacea methanolic extract and chloroform fraction have phototoxicity in A. salina bioassay system and their toxic effect is related to phototoxic constituents such as psoralen.

  1. Beoordeling van gereinigde grond. IV. Toepassing van bioassays met planten en regenwormen op referentiegronden

    NARCIS (Netherlands)

    van Gestel CAM; Dirven-van Breemen EM; Kamerman JW

    1992-01-01

    Within the framework of the project "Evaluation of decontaminated soil", the applicability of bioassays with earthworms and plants for the quality assessment of decontaminated soil is investigated. In order to establish a reference system for "normal" levels of metals in

  2. False-nearest-neighbors algorithm and noise-corrupted time series

    Science.gov (United States)

    Rhodes, Carl; Morari, Manfred

    1997-05-01

    The false-nearest-neighbors (FNN) algorithm was originally developed to determine the embedding dimension for autonomous time series. For noise-free computer-generated time series, the algorithm does a good job in predicting the embedding dimension. However, the problem of predicting the embedding dimension when the time-series data are corrupted by noise was not fully examined in the original studies of the FNN algorithm. Here it is shown that with large data sets, even small amounts of noise can lead to incorrect prediction of the embedding dimension. Surprisingly, as the length of the time series analyzed by FNN grows larger, the cause of incorrect prediction becomes more pronounced. An analysis of the effect of noise on the FNN algorithm and a solution for dealing with the effects of noise are given here. Some results on the theoretically correct choice of the FNN threshold are also presented.

  3. Phosphorous vacancy nearest neighbor hopping induced instabilities in InP capacitors II. Computer simulation

    International Nuclear Information System (INIS)

    Juang, M.T.; Wager, J.F.; Van Vechten, J.A.

    1988-01-01

    Drain current drift in InP metal insulator semiconductor devices display distinct activation energies and pre-exponential factors. The authors have given evidence that these result from two physical mechanisms: thermionic tunneling of electrons into native oxide traps and phosphorous vacancy nearest neighbor hopping (PVNNH). They here present a computer simulation of the effect of the PVNHH mechanism on flatband voltage shift vs. bias stress time measurements. The simulation is based on an analysis of the kinetics of the PVNNH defect reaction sequence in which the electron concentration in the channel is related to the applied bias by a solution of the Poisson equation. The simulation demonstrates quantitatively that the temperature dependence of the flatband shift is associated with PVNNH for temperatures above room temperature

  4. False-nearest-neighbors algorithm and noise-corrupted time series

    International Nuclear Information System (INIS)

    Rhodes, C.; Morari, M.

    1997-01-01

    The false-nearest-neighbors (FNN) algorithm was originally developed to determine the embedding dimension for autonomous time series. For noise-free computer-generated time series, the algorithm does a good job in predicting the embedding dimension. However, the problem of predicting the embedding dimension when the time-series data are corrupted by noise was not fully examined in the original studies of the FNN algorithm. Here it is shown that with large data sets, even small amounts of noise can lead to incorrect prediction of the embedding dimension. Surprisingly, as the length of the time series analyzed by FNN grows larger, the cause of incorrect prediction becomes more pronounced. An analysis of the effect of noise on the FNN algorithm and a solution for dealing with the effects of noise are given here. Some results on the theoretically correct choice of the FNN threshold are also presented. copyright 1997 The American Physical Society

  5. Calculation of nucleation free energy for duplex oligomers in the context of nearest neighbor models.

    Science.gov (United States)

    Guerra, João Carlos de Oliveira

    2013-08-01

    Additive physical properties of DNA double strand polymers have been expanded in terms of 8 irreducible parameters. This provided consistency relations among the corresponding 10 duplex dimer contributions. To allow for oligomer analysis, end parameters were often added, and this would add extra degrees of freedom to the fore mentioned parameters. Statistical mechanics approaches were then connected to the nearest neighbor (NN) approach in the framework of the two-states model. Ad hoc end effects were thus (wrongly) correlated to nucleation phenomena and this lead to a critique for its role in NN modeling. With this motivation, a new NN model is proposed that accommodates the nucleation free energies. The model relates the nucleation free energy to the mean composition of the chain and permits to obtain a good estimate for the free energy associated only to the Watson-Crick base pairings. Copyright © 2013 Wiley Periodicals, Inc.

  6. Water quality bioassay using selected protozoa. I. [Paramecium candatum; Amoeba proteus; Euglena gracilis

    Energy Technology Data Exchange (ETDEWEB)

    Mills, W.L.

    1976-01-01

    The suitability of certain species of protozoa as indicators of water quality has been determined. Experiments were conducted under laboratory conditions to standardize a bioassay procedure for water quality using either Paramecium caudatum, Amoeba proteus, or Euglena gracilis as the indicator organism. The bioassay, which consists of exposing the organisms to a known concentration of pollutant under laboratory conditions, followed by microscopic observation to establish the time of death, affords a reliable, convenient and inexpensive way to monitor for water quality.

  7. Selection of a bioassay battery to assess toxicity in the affluents and effluents of three water-treatment plants

    Directory of Open Access Journals (Sweden)

    Paola Bohórquez-Echeverry

    2012-08-01

    Full Text Available The assessment of water quality includes the analysis of both physical-chemical and microbiological parameters. However,none of these evaluates the biological effect that can be generated in ecosystems or humans. In order to define the most suitable organismsto evaluate the toxicity in the affluent and effluent of three drinking-water treatment plants, five acute toxicity bioassays were used,incorporating three taxonomic groups of the food chain. Materials and methods. The bioassays used were Daphnia magna and Hydraattenuata as animal models, Lactuca sativa and Pseudokirchneriella subcapitata as plant models, and Photobacterium leioghnathi asbacterial model. To meet this objective, selection criteria of the organisms evaluated and cluster analysis were used to identify the mostsensitive in the affluent and effluent of each plant. Results. All organisms are potentially useful in the assessment of water quality bymeeting four essential requirements and 17 desirable requirements equivalent to 100% acceptability, except P. leioghnathi which doesnot meet two essential requirements that are the IC50 for the toxic reference and the confidence interval. The animal, plant and bacterialmodels showed different levels of sensitivity at the entrance and exit of the water treatment systems. Conclusions. H. attenuata, P.subcapitata and P. leioghnathi were the most effective organisms in detecting toxicity levels in the affluents and D. magna, P. subcapitataand P. leioghnathi in the effluents.

  8. Development and validation of microbial bioassay for quantification of Levofloxacin in pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    Nishant A. Dafale

    2015-02-01

    Full Text Available The aim of this study was to develop and validate a simple, sensitive, precise and cost-effective one-level agar diffusion (5+1 bioassay for estimation of potency and bioactivity of Levofloxacin in pharmaceutical preparation which has not yet been reported in any pharmacopoeia. Among 16 microbial strains, Bacillus pumilus ATCC-14884 was selected as the most significant strain against Levofloxacin. Bioassay was optimized by investigating several factors such as buffer pH, inoculums concentration and reference standard concentration. Identification of Levofloxacin in commercial sample Levoflox tablet was done by FTIR spectroscopy. Mean potency recovery value for Levofloxacin in Levoflox tablet was estimated as 100.90%. A validated bioassay method showed linearity (r2=0.988, precision (Interday RSD=1.05%, between analyst RSD=1.02% and accuracy (101.23%, RSD=0.72%. Bioassay was correlated with HPLC using same sample and estimated potencies were 100.90% and 99.37%, respectively. Results show that bioassay is a suitable method for estimation of potency and bioactivity of Levofloxacin pharmaceutical preparations. Keywords: Levofloxacin, Antibiotic resistance, Microbiological bioassay, HPLC, Pharmacopoeia

  9. Forecasting Space Weather Events for a Neighboring World

    Science.gov (United States)

    Zheng, Yihua; Mason, Tom; Wood, Erin L.

    2015-01-01

    Shortly after NASA's Mars Atmosphere and Volatile EvolutioN mission (MAVEN) spacecraft entered Mars' orbit on 21 September 2014, scientists glimpsed the Martian atmosphere's response to a front of solar energetic particles (SEPs) and an associated coronal mass ejection (CME). In response to some solar flares and CMEs, streams of SEPs burst from the solar atmosphere and are further accelerated in the interplanetary medium between the Sun and the planets. These particles deposit their energy and momentum into anything in their path, including the Martian atmosphere and MAVEN particle detectors. MAVEN scientists had been alerted to the likely CME-Mars encounter by a space weather prediction system that had its origins in space weather forecasting for Earth but now forecasts space weather for Earth's neighboring planets. The two Solar Terrestrial Relations Observatory spacecraft and Solar Heliospheric Observatory observed a CME on 26 September, with a trajectory that suggested a Mars intercept. A computer model developed for solar wind prediction, the Wang-Sheeley-Arge-Enlil cone model [e.g., Zheng et al., 2013; Parsons et al., 2011], running in real time at the Community Coordinated Modeling Center (CCMC) located at NASA Goddard since 2006, showed the CME propagating in the direction of Mars (Figure 1). According to MAVEN particle detectors, the disturbance and accompanying SEP enhancement at the leading edge of the CME reached Mars at approximately 17 hours Universal Time on 29 September 2014. Such SEPs may have a profound effect on atmospheric escape - they are believed to be a possible means for driving atmospheric loss. SEPs can cause loss of Mars' upper atmosphere through several loss mechanisms including sputtering of the atmosphere. Sputtering occurs when atoms are ejected from the atmosphere due to impacts with energetic particles.

  10. Isolation of antibacterial compounds from Quercus dilatata L. through bioassay guided fractionation

    Directory of Open Access Journals (Sweden)

    Jamil Maryam

    2012-05-01

    Full Text Available Abstract Background Four medicinal plants (Chrozophora hierosolymitana Spreng, Chrysanthemum leucanthemum L., Ephedra gerardiana Wall. ex Stapf, and Quercus dilatata L. used by indigenous healers to treat various infectious diseases were selected for the present study. The major objective of the present study was isolation and characterization of antimicrobial components from the crude plant extracts using bioassay guided fractionation. Methods Seven methanolic extracts of the four plants were screened to identify any antimicrobial agents present in them. The active crude plant extract was fractionated first by solvent partitioning and then by HPLC. Characterization of the active fractions was done by using spectrophotometer. Results All the seven methanolic extracts showed low antifungal activity, however, when these extracts were tested for antibacterial activity, significant activity was exhibited by two extracts. The extract of aerial parts of Q. dilatata was most active and therefore, was selected for further analysis. Initially fractionation was done by solvent-solvent partitioning and out of six partitioned fractions, ethanol fraction was selected on the basis of results of antibacterial activity and phytochemical analysis. Further, fractionation was carried out by RP- HPLC and purified active subfractions were characterized by comparing their absorption spectra with that of the known natural products isolated from the plants of Quercus genus. Discussion and conclusion The results suggest that this is the first report of the isolated antibacterial compounds from this genus.

  11. Working with Family, Friend, and Neighbor Caregivers: Lessons from Four Diverse Communities

    Science.gov (United States)

    Powell, Douglas R.

    2011-01-01

    This article is excerpted from "Who's Watching the Babies? Improving the Quality of Family, Friend, and Neighbor Care" by Douglas R. Powell ("ZERO TO THREE," 2008). The article explores questions about program development and implementation strategies for supporting Family, Friend, and Neighbor (FFN) caregivers: How do programs and their host…

  12. 77 FR 51533 - Good Neighbor Environmental Board Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2012-08-24

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9720-5] Good Neighbor Environmental Board Notification of... Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will... with Mexico. Purpose of Meeting: The purpose of this teleconference is to discuss and approve the Good...

  13. 76 FR 62062 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2011-10-06

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9476-4] Good Neighbor Environmental Board; Notification of... Act, Public Law 92- 463, notice is hereby given that the Good Neighbor Environmental Board (GNEB) will... with Mexico. Purpose of Meeting: The purpose of this teleconference is to discuss and approve the Good...

  14. Application of Nearest Neighbor Indices in Persian Oak (Quercus brantii var. persica Coppice Stands of Zagros Forests

    Directory of Open Access Journals (Sweden)

    Y. Erfanifard

    2014-03-01

    Full Text Available The ecological relationship between trees is important in the sustainable management of forests. Studying this relationship in spatial ecology, different indices are applied that are based on distance to nearest neighbor. The aim of this research was introduction of important indices based on nearest neighbor analysis and their application in the investigation of ecological relationship between Persian oak coppice trees in Zagros forests. A 9 ha plot of these forests in Kohgilouye - BoyerAhmad province was selected that was completely homogeneous. This plot was covered with Persian oak coppice trees that their point map was obtained after registering their spatial location. Five nearest neighbor indices of G(r, F(r, J(r, GF(r and CE were then applied to study the spatial pattern and relationship of these trees. The results showed that Persian oak coppice trees were located regularly in the homogeneous plot and they were not dependent ecologically. These trees were independent and did not affect the establishment of each other.

  15. Remote Field Eddy Curent Signal Modeling for the Gap Measurement of Neighboring Tubes

    Science.gov (United States)

    Jung, H. K.; Lee, D. H.; Lee, Y. S.

    2005-04-01

    The fuel channels in the Canadian Deuterium Uranium (CANDU) reactor consist of the coaxial pressure tube (PT) and the calandria tube (CT). The Liquid injection nozzle (LIN) is cross aligned with the fuel channel to control the reactor by injecting poison. For a safe operation, the gap between the LIN and CT should be maintained in order to prevent a contact of the neighboring tubes. The remote field eddy current (RFEC) method was applied to measure the gap between a nonmagnetic Zircaloy-2 liquid injection nozzle (LIN) and a Zircaloy-2 calandria tube. Under the condition of inserting the RFEC probe into the coaxial tubes and of crossing a LIN above or under the CT, the modeling of a LIN signal is needed to check the possibility of a gap measurement. The Volume Integral Code S/W which covers the axi-symmetric 3D configuration has been very rarely applied to obtain a LIN signal. This problem was solved by assuming a LIN as a flaw which can be described as a complete 3D object. This simulated LIN signal was verified by performing the laboratory experiment. The gap between the LIN and CT can be correlated with the amplitude of the LIN signals in the voltage plane. Typical noises in the fuel channel were the relative constriction, the change in the pressure tube diameter (fill-factor), thickness variation, and so on. These noise signals were simulated by using the modeling and were analyzed by considering their dependency on the phase angle and amplitude of the voltage plane in order to separate the gap signal from them. It could be concluded that the voltage plane analysis of the simulated RFEC signals were effective for obtaining the gap measurement of the neighboring tube.

  16. Detection of Burkholderia pseudomallei O-antigen serotypes in near-neighbor species

    Directory of Open Access Journals (Sweden)

    Stone Joshua K

    2012-11-01

    Full Text Available Abstract Background Burkholderia pseudomallei is the etiological agent of melioidosis and a CDC category B select agent with no available effective vaccine. Previous immunizations in mice have utilized the lipopolysaccharide (LPS as a potential vaccine target because it is known as one of the most important antigenic epitopes in B. pseudomallei. Complicating this strategy are the four different B. pseudomallei LPS O-antigen types: A, B, B2, and rough. Sero-crossreactivity is common among O-antigens of Burkholderia species. Here, we identified the presence of multiple B. pseudomallei O-antigen types and sero-crossreactivity in its near-neighbor species. Results PCR screening of O-antigen biosynthesis genes, phenotypic characterization using SDS-PAGE, and immunoblot analysis showed that majority of B. mallei and B. thailandensis strains contained the typical O-antigen type A. In contrast, most of B. ubonensis and B. thailandensis-like strains expressed the atypical O-antigen types B and B2, respectively. Most B. oklahomensis strains expressed a distinct and non-seroreactive O-antigen type, except strain E0147 which expressed O-antigen type A. O-antigen type B2 was also detected in B. thailandensis 82172, B. ubonensis MSMB108, and Burkholderia sp. MSMB175. Interestingly, B. thailandensis-like MSMB43 contained a novel serotype B positive O-antigen. Conclusions This study expands the number of species which express B. pseudomallei O-antigen types. Further work is required to elucidate the full structures and how closely these are to the B. pseudomallei O-antigens, which will ultimately determine the efficacy of the near-neighbor B serotypes for vaccine development.

  17. A Regression-based K nearest neighbor algorithm for gene function prediction from heterogeneous data

    Directory of Open Access Journals (Sweden)

    Ruzzo Walter L

    2006-03-01

    Full Text Available Abstract Background As a variety of functional genomic and proteomic techniques become available, there is an increasing need for functional analysis methodologies that integrate heterogeneous data sources. Methods In this paper, we address this issue by proposing a general framework for gene function prediction based on the k-nearest-neighbor (KNN algorithm. The choice of KNN is motivated by its simplicity, flexibility to incorporate different data types and adaptability to irregular feature spaces. A weakness of traditional KNN methods, especially when handling heterogeneous data, is that performance is subject to the often ad hoc choice of similarity metric. To address this weakness, we apply regression methods to infer a similarity metric as a weighted combination of a set of base similarity measures, which helps to locate the neighbors that are most likely to be in the same class as the target gene. We also suggest a novel voting scheme to generate confidence scores that estimate the accuracy of predictions. The method gracefully extends to multi-way classification problems. Results We apply this technique to gene function prediction according to three well-known Escherichia coli classification schemes suggested by biologists, using information derived from microarray and genome sequencing data. We demonstrate that our algorithm dramatically outperforms the naive KNN methods and is competitive with support vector machine (SVM algorithms for integrating heterogenous data. We also show that by combining different data sources, prediction accuracy can improve significantly. Conclusion Our extension of KNN with automatic feature weighting, multi-class prediction, and probabilistic inference, enhance prediction accuracy significantly while remaining efficient, intuitive and flexible. This general framework can also be applied to similar classification problems involving heterogeneous datasets.

  18. Characteristics of Broadband Seismic Noise in Taiwan and Neighboring Islands

    Science.gov (United States)

    Chen, Ching-Wei; Rau, Ruey-Juin

    2017-04-01

    We used seismic waveform data from 115 broad-band stations of BATS (Institute of Earth Science, Academia Sinica) and Central Weather Bureau Seismic Network from 2012 to 2016 for noise-level mapping in Taiwan and neighboring islands. We computed Power Spectral Density (PSD) for each station and analyzed long-term variance of microseism energy and polarizations of noise for severe weather events. The island of Taiwan is surrounded by ocean and the Central Range which has the highest peak Jade Mountain at 3,952 meters height occupies more than 66% of the island and departs it into the east and west coasts. The geographic settings then result in the high population density in the western plain and northern Taiwan. The dominant noise source in the microseism band (periods from 4-20 seconds) is the coupling between the near-coast ocean and sea floor which produces the high noise of averaging -130 dB along the west coastal area. In the eastern volcanic-arc coastal areas, the noise level is about 7% smaller than the west coast due to its deeper offshore water depth. As for the shorter periods (0.1-0.25 seconds) band, the so-called culture noise, an anthropic activity variance with the highest -103 dB can be identified in the metropolitan areas, such as the Taipei city and the noise level in the Central Range area is averaging -138 dB. Moreover, the noise also shows a daily and temporal evolution mainly related to the traffic effect. Furthermore, we determined the noise level for the entire island of Taiwan during 26-28 September, 2016, when the typhoon Megi hit the island and retrieved the enhancement of secondary microseism energy for each stations. Typhoon Megi landed in eastern and central Taiwan and reached the maximum wind speed of 45m/s in the surrounded eyewall. The Central Range, as a barrier, decreased the wind speed in southern Taiwan making an enhancement less than 10 dB, while in northern Taiwan where the direction the typhoon headed to, can reach more than 35

  19. Controllable Assembly of Enzymes for Multiplexed Lab-on-a-Chip Bioassays with a Tunable Detection Range.

    Science.gov (United States)

    Xianyu, Yunlei; Wu, Jing; Chen, Yiping; Zheng, Wenshu; Xie, Mengxia; Jiang, Xingyu

    2018-02-26

    Multiplexed analysis of molecules with different concentrations requires assays with a tunable detection range. A strategy is outlined that uses click chemistry to assemble horseradish peroxidase in a controlled fashion to generate enzyme assemblies as probes for multiplexed bioassays. This controllable assembly of enzymes on detection antibodies allows for lab-on-a-chip immunoassays with a tunable detection range from pg mL -1 to μg mL -1 . Simultaneous, multiplexed bioassays of clinically relevant inflammatory biomarkers in serum are demonstrated in one lab-on-a-chip format, with a limit of detection of 0.47 pg mL -1 for interleukin-6, 2.6 pg mL -1 for procalcitonin, and 40 ng mL -1 for C-reactive protein. This controlled assembly technique provides a multiplexed platform for simultaneous and quantitative analyses of both low-abundance and high-abundance biomarkers with a broad detection range, which holds great promise as a point-of-care platform for biomedical diagnostics. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Temperature threshold models for benthic macroinvertebrates in Idaho wadeable streams and neighboring ecoregions.

    Science.gov (United States)

    Richards, David C; Lester, Gary; Pfeiffer, John; Pappani, Jason

    2018-02-07

    Water temperatures are warming throughout the world including the Pacific Northwest, USA. Benthic macroinvertebrates are one of the most important and widely used indicators of freshwater impairment; however, their response to increased water temperatures and their use for monitoring water temperature impairment has been hindered by lack of knowledge of temperature occurrences, threshold change points, or indicator taxa. We present new analysis of a large macroinvertebrate database provided by Idaho Department of Environmental Quality from wadeable streams in Idaho that is to be used in conjunction with our previous analyses. This new analysis provides threshold change points for over 400 taxa along an increasing temperature gradient and provides a list of statistically important indicator taxa. The macroinvertebrate assemblage temperature change point for the taxa that decreased with increased temperatures was determined to be about 20.5 °C and for the taxa assemblage that increased with increased temperatures was about 11.5 °C. Results of this new analysis combined with our previous analysis will also be useful for others in neighboring regions where these taxa occur.

  1. Assessing arsenic bioavailability through the use of bioassays

    Science.gov (United States)

    Diesel, E.; Nadimpalli, M.; Hull, M.; Schreiber, M. E.; Vikesland, P.

    2009-12-01

    Various methods have been used to characterize the bioavailability of a contaminant, including chemical extractions from soils, toxicity tests, bioaccumulation measurements, estimation from soil properties, in vitro/in vivo tests, and microbial biossays. Unfortunately, these tests are all unique (i.e. they measure bioavailability through different mechanisms) and it is difficult to compare measurements collected using one method to those collected from another. Additionally, there are fundamental aspects of bioavailability research that require further study. In particular, changes in bioavailability over time are not well understood, as well as what the geochemical controls are on changes in bioavailability. In addition, there are no studies aimed at the integration of bioavailability measurements and potential geochemical controls. This research project seeks to find a standard set of assays and sensors that can be used to assess arsenic bioavailability at any field site, as well as to use these tools and techniques to better understand changes in, and controls on, arsenic bioavailability. The bioassays to be utilized in this research are a bioluminescent E. coli assay and a Corbicula fluminea (Asian clam) assay. Preliminary experiments to determine the suitability of the E. coli and C. fluminea assays have been completed. The E. coli assay can be utilized to analyze As(III) and As(V) with a linear standard curve between 5 and 200 ppb for As(III) and 100 ppb and 5 ppm for As(V); no bioluminescent response above background was elicited in the presence of Roxarsone, an organoarsenical. The C. fluminea assay is capable of bioaccumulating As(III), As(V), Roxarsone, and MSMA, with As(III) being the most readily accumulated, followed by As(V), Roxarsone and MSMA, respectively. Additional research will include assessing bioavailability of various arsenic species adsorbed to natural colloidal materials (i.e. clays, iron oxides, NOM) to the E. coli and C. fluminea assays

  2. A Hamiltonian Replica Exchange Approach and Its Application to the Study of Side-Chain Type and Neighbor Effects on Peptide Backbone Conformations.

    Science.gov (United States)

    Xu, Chao; Wang, Jun; Liu, Haiyan

    2008-08-01

    We presented a Hamiltonian replica exchange approach and applied it to investigate the effects of various factors on the conformational equilibrium of peptide backbone. In different replicas, biasing potentials of varying strengths are applied to all backbone (φ,ψ) torsional angle pairs to overcome sampling barriers. A general form of constructing biasing potentials based on a reference free energy surface is employed to minimize sampling in physically irrelevant parts of the conformational space. An extension of the weighted histogram analysis formulation allows for conformational free energy surfaces to be computed using all replicas, including those with biased Hamiltonians. This approach can significantly reduce the statistical uncertainties in computed free energies. For the peptide systems considered, it allows for effects of the order of 0.5-1 kJ/mol to be quantified using explicit solvent simulations. We applied this approach to capped peptides of 2-5 peptide units containing Ala, Phe, or Val in explicit water solvent and focused on how the conformational equilibrium of a single pair of backbone angles are influenced by changing the residue types of the same and neighboring residues as well as conformations of neighboring residues. For the effects of changing side-chain types of the same residue, our results consistently showed increased preference of β for Phe and Val relative to Ala. As for neighbor effects, our results not only indicated that they can be as large as the effects of changing the side-chain type of the same residue but also led to several new insights. We found that for the N-terminal neighbors, their conformations seem to have large effects. Relative to the β conformer of an N-terminal neighbor, its α conformer stabilizes the β conformer of its next Ala disregarding the residue type of the neighbor. For C-terminal neighbors, their chemical identities seem to play more important roles. Val as the C-terminal neighbor significantly

  3. Electrochemical detection of miRNA-222 by use of a magnetic bead-based bioassay.

    Science.gov (United States)

    Bettazzi, Francesca; Hamid-Asl, Ezat; Esposito, Carla Lucia; Quintavalle, Cristina; Formisano, Nello; Laschi, Serena; Catuogno, Silvia; Iaboni, Margherita; Marrazza, Giovanna; Mascini, Marco; Cerchia, Laura; De Franciscis, Vittorio; Condorelli, Gerolama; Palchetti, Ilaria

    2013-01-01

    MicroRNAs (miRNAs, miRs) are naturally occurring small RNAs (approximately 22 nucleotides in length) that have critical functions in a variety of biological processes, including tumorigenesis. They are an important target for detection technology for future medical diagnostics. In this paper we report an electrochemical method for miRNA detection based on paramagnetic beads and enzyme amplification. In particular, miR 222 was chosen as model sequence, because of its involvement in brain, lung, and liver cancers. The proposed bioassay is based on biotinylated DNA capture probes immobilized on streptavidin-coated paramagnetic beads. Total RNA was extracted from the cell sample, enriched for small RNA, biotinylated, and then hybridized with the capture probe on the beads. The beads were then incubated with streptavidin-alkaline phosphatase and exposed to the appropriate enzymatic substrate. The product of the enzymatic reaction was electrochemically monitored. The assay was finally tested with a compact microfluidic device which enables multiplexed analysis of eight different samples with a detection limit of 7 pmol L(-1) and RSD = 15 %. RNA samples from non-small-cell lung cancer and glioblastoma cell lines were also analyzed.

  4. Submicron polymer particles containing fluorescent semiconductor nanocrystals CdSe/ZnS for bioassays.

    Science.gov (United States)

    Generalova, Alla N; Sizova, Svetlana V; Zdobnova, Tatiana A; Zarifullina, Margarita M; Artemyev, Michail V; Baranov, Alexander V; Oleinikov, Vladimir A; Zubov, Vitaly P; Deyev, Sergey M

    2011-02-01

    This study aimed to design a panel of uniform particulate biochemical reagents and to test them in specific bioassays. These reagents are polymer particles of different sizes doped with semiconductor nanocrystals and conjugated with either full-size antibodies or recombinant mini-antibodies (4D5 scFv fragment) designed by genetic engineering approaches. A panel of highly fluorescent polymer particles (150-800 nm) were formed by embedding CdSe/ZnS nanocrystals (quantum dots) into preformed polyacrolein and poly(acrolein-co-styrene) particles. Morphology, content and fluorescence characteristics of the prepared materials were studied by laser correlation spectroscopy, spectrophotometry, optical and fluorescent microscopy and fluorimetry. The obtained fluorescent particles sensitized by anti-Yersinia pestis antibodies were used for rapid agglutination glass test suitable for screening analysis of Y. pestis antigen and for microtiter particle agglutination, which, owing to its speed and simplicity, is very beneficial for diagnostic detection of Y. pestis antigen. Recombinant 4D5 scFv antibodies designed and conjugated with polymer particles containing quantum dots provide multipoint highly specific binding with cancer marker HER2/neu on the surface of SKOV-3 cell.

  5. Multi-modal particle manipulator to enhance bead-based bioassays

    Science.gov (United States)

    Glynne-Jones, P.; Boltryk, R. J.; Hill, M.; Zhang, F.; Dong, L.; Wilkinson, J. S.; Brown, T.; Melvin, T.; Harris, N. R.

    2010-01-01

    By sequentially pushing micro-beads towards and away from a sensing surface, we show that ultrasonic radiation forces can be used to enhance the interaction between a functionalized glass surface and polystyrene micro-beads, and distinguish those that bind to the surface, ultimately by using an integrated optical waveguide implanted in the reflector to facilitate optical detection. The movement towards and immobilization of streptavidin coated beads onto a biotin functionalized waveguide surface is achieved by using a quarter-wavelength mode pushing beads onto the surface, while the removal of non-specifically bound beads uses a second quarter-wavelength mode which exhibits a kinetic energy maxima at the boundary between the carrier layer and fluid, drawing beads towards this surface. This has been achieved using a multi-modal acoustic device which exhibits both these quarter-wavelength resonances. Both 1-D acoustic modeling and finite element analysis has been used to design this device and investigate the spatial uniformity of the field. We demonstrate experimentally that 90% of specifically bound beads remain attached after applying ultrasound, with 80% of non-specifically bound control beads being successfully removed acoustically. This approach overcomes problems associated with lengthy sedimentation processes used for bead-based bioassays and surface (electrostatic) forces, which delay or prevent immobilization. We explain the potential of this technique in the development of DNA and protein assays in terms of detection speed and multiplexing.

  6. Evaluation and QSAR modeling on multiple endpoints of estrogen activity based on different bioassays.

    Science.gov (United States)

    Liu, Huanxiang; Papa, Ester; Gramatica, Paola

    2008-02-01

    There is a great need for an effective means of rapidly assessing endocrine-disrupting activity, especially estrogen-simulating activity, due to the large number of chemicals that have serious adverse effects on the environment. Many approaches using a variety of biological screening assays are used to identify endocrine disrupting chemicals. The present investigation analyzes the consistency and peculiarity of information from different experimental assays collected from a literature survey, by studying the correlation of the different endpoints. In addition, the activity values of more widely used selected bioassays have been combined by principle components analysis (PCA) to build one cumulative endpoint, the estrogen activity index (EAI), for priority setting to identify chemicals most likely possessing estrogen activity for early entry into screening. This index was then modeled using only a few theoretical molecular descriptors. The constructed MLR-QSAR model has been statistically validated for its predictive power, and can be proposed as a preliminary evaluative method to screen/prioritize estrogens according to their integrated estrogen activity, just starting from molecular structure.

  7. Tree communities of lowland warm-temperate old-growth and neighboring shelterbelt forests in the Shikoku region of southwestern Japan

    Science.gov (United States)

    Shigeo Kuramoto; Shigenori Oshioka; Takahisa Hirayama; Kaori Sato; Yasumasa Hirata

    2007-01-01

    We characterized the tree species composition of a 30 ha old-growth and neighboring shelterbelt (reserved buffer strips among conifer plantations) in warm-temperate forests in the Shikoku region of southwestern Japan. Using a two-way indicator species analysis of data from 28 plots, we identified four structural groups in terms of relative basal area. These structural...

  8. Assessment of Sediment Heavy Metals Pollution Using Screening Methods (XRF, TGA/MS, XRPD and Earthworms Bioassay)

    Science.gov (United States)

    Findoráková, Lenka; Šestinová, Ol'ga; Hančul'ák, Jozef; Fedorová, Erika; Zorkovská, Anna

    2016-10-01

    The aim of this study is focused on the use of screening methods (TG/DTA coupled with MS, XRF, AAS, XRPD and earthworm bioassay) for sediments pollution assessing by heavy metals (Cu, Zn, Pb, Hg) coming from the former mining workloads in the central Spis, Eastern Slovakia. The screening methods (XRF, AAS) indicated pollution of studied sediments by Cu, Zn, Pb, Hg. The earthworms Dendrobaena veneta caused in some studied samples decrease of heavy metals concentration after their 7 days’ exposure in sediments. The other screening methods such as thermal analysis and XRPD analysis, does not confirm the specifically changes in physicochemical properties comparing the properties before and after 7 days’ earthworm's exposure.

  9. Neighboring trees affect ectomycorrhizal fungal community composition in a woodland-forest ecotone.

    Science.gov (United States)

    Hubert, Nathaniel A; Gehring, Catherine A

    2008-09-01

    Ectomycorrhizal fungi (EMF) are frequently species rich and functionally diverse; yet, our knowledge of the environmental factors that influence local EMF diversity and species composition remains poor. In particular, little is known about the influence of neighboring plants on EMF community structure. We tested the hypothesis that the EMF of plants with heterospecific neighbors would differ in species richness and community composition from the EMF of plants with conspecific neighbors. We conducted our study at the ecotone between pinyon (Pinus edulis)-juniper (Juniperus monosperma) woodland and ponderosa pine (Pinus ponderosa) forest in northern Arizona, USA where the dominant trees formed associations with either EMF (P. edulis and P. ponderosa) or arbuscular mycorrhizal fungi (AMF; J. monosperma). We also compared the EMF communities of pinyon and ponderosa pines where their rhizospheres overlapped. The EMF community composition, but not species richness of pinyon pines was significantly influenced by neighboring AM juniper, but not by neighboring EM ponderosa pine. Ponderosa pine EMF communities were different in species composition when growing in association with pinyon pine than when growing in association with a conspecific. The EMF communities of pinyon and ponderosa pines were similar where their rhizospheres overlapped consisting of primarily the same species in similar relative abundance. Our findings suggest that neighboring tree species identity shaped EMF community structure, but that these effects were specific to host-neighbor combinations. The overlap in community composition between pinyon pine and ponderosa pine suggests that these tree species may serve as reservoirs of EMF inoculum for one another.

  10. Differentiation Using Microwave Plasma Torch Desorption Mass Spectrometry of Navel Oranges Cultivated in Neighboring Habitats.

    Science.gov (United States)

    Wang, Xinchen; Yang, Meiling; Wang, Zhiyuan; Zhang, Hua; Wang, Guofeng; Deng, Min; Chen, Huanwen; Luo, Liping

    2017-03-22

    The molecular fingerprinting of intact fruit samples combined with statistical data analysis can allow the assessment of fruit quality and location of origin. Herein, microwave plasma torch desorption ionization mass spectrometry (MPT-MS) was applied to produce molecular fingerprints for the juice sac and exocarp of navel oranges cultivated in three closely located habitats, and the mass spectrometric fingerprints were differentiated by principal component analysis (PCA). Because of the relatively high temperature and high ionization efficiency of MPT, the volatile aroma compounds and semivolatile chemicals in the navel oranges were sensitively detected and confidently identified by collision induced dissociation (CID). The limit of detection (LOD) of MPT-MS for vanillin was 0.119 μg/L, with the relative standard deviation (RSD, n = 10) of 1.7%. The results showed that MPT-MS could be a powerful analytical platform for the sensitive molecular analysis of fruits at molecular level with high chemical specificity, allowing differentiation between the same sorts grown in neighboring habitats.

  11. Weaver ants Oecophylla smaragdina encounter nasty neighbors rather than dear enemies.

    Science.gov (United States)

    Newey, Philip S; Robson, Simon K A; Crozier, Ross H

    2010-08-01

    The evolution of territorial behavior requires that the benefits of territoriality outweigh the costs. The costs are primarily those of territorial defense against encroaching neighbors or against floaters seeking to establish their own territory. One way to reduce the cost of defense might be to restrict serious conflict to encounters with those posing the greatest threat. Studies of many animals have found that less aggression is shown toward neighbors than toward, strangers, a phenomenon known as the "dear enemy" effect. However, the opposite can also be true, namely, that more aggression is shown toward neighbors than strangers: the "nasty neighbor" effect. This may be particularly true of group-living species that defend a resource-based territory. Here we show that (1) colonies of the weaver ant Oecophylla smaragdina were able to recognize a greater proportion of workers from neighboring colonies as non-colony members; and (2) when recognized as non-colony members, more aggression was exhibited toward neighbors than non-neighbors. We present for the first time evidence that differential levels of aggression involve both a perceptual and behavioral component. On the other hand, we found no evidence that weaver ant workers were better able to recognize workers from previously unknown colonies or responded more aggressively to them, even after a 10-day period of contact. This contrasts with other species in which rapid learning of the identity of new potential enemies has been demonstrated. We suggest that such a response is unnecessary for weaver ants, as encounters with intruders from non-neighboring colonies are probably rare and of little consequence. This study adds to the growing body of evidence that the nasty neighbor effect may be much more common than the dear enemy effect among group-living species.

  12. The Application of Determining Students’ Graduation Status of STMIK Palangkaraya Using K-Nearest Neighbors Method

    Science.gov (United States)

    Rusdiana, Lili; Marfuah

    2017-12-01

    K-Nearest Neighbors method is one of methods used for classification which calculate a value to find out the closest in distance. It is used to group a set of data such as students’ graduation status that are got from the amount of course credits taken by them, the grade point average (AVG), and the mini-thesis grade. The study is conducted to know the results of using K-Nearest Neighbors method on the application of determining students’ graduation status, so it can be analyzed from the method used, the data, and the application constructed. The aim of this study is to find out the application results by using K-Nearest Neighbors concept to determine students’ graduation status using the data of STMIK Palangkaraya students. The development of the software used Extreme Programming, since it was appropriate and precise for this study which was to quickly finish the project. The application was created using Microsoft Office Excel 2007 for the training data and Matlab 7 to implement the application. The result of K-Nearest Neighbors method on the application of determining students’ graduation status was 92.5%. It could determine the predicate graduation of 94 data used from the initial data before the processing as many as 136 data which the maximal training data was 50data. The K-Nearest Neighbors method is one of methods used to group a set of data based on the closest value, so that using K-Nearest Neighbors method agreed with this study. The results of K-Nearest Neighbors method on the application of determining students’ graduation status was 92.5% could determine the predicate graduation which is the maximal training data. The K-Nearest Neighbors method is one of methods used to group a set of data based on the closest value, so that using K-Nearest Neighbors method agreed with this study.

  13. Microbial Detoxification of Deoxynivalenol (DON), Assessed via a Lemna minor L. Bioassay, through Biotransformation to 3-epi-DON and 3-epi-DOM-1.

    Science.gov (United States)

    Vanhoutte, Ilse; De Mets, Laura; De Boevre, Marthe; Uka, Valdet; Di Mavungu, José Diana; De Saeger, Sarah; De Gelder, Leen; Audenaert, Kris

    2017-02-13

    Mycotoxins are toxic metabolites produced by fungi. To mitigate mycotoxins in food or feed, biotransformation is an emerging technology in which microorganisms degrade toxins into non-toxic metabolites. To monitor deoxynivalenol (DON) biotransformation, analytical tools such as ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) are typically used. However, these techniques do not give a decisive answer about the remaining toxicity of possible biotransformation products. Hence, a bioassay using Lemna minor L. was developed. A dose-response analysis revealed significant inhibition in the growth of L. minor exposed to DON concentrations of 0.25 mg/L and higher. Concentrations above 1 mg/L were lethal for the plant. This bioassay is far more sensitive than previously described systems. The bioassay was implemented to screen microbial enrichment cultures, originating from rumen fluid, soil, digestate and activated sludge, on their biotransformation and detoxification capability of DON. The enrichment cultures originating from soil and activated sludge were capable of detoxifying and degrading 5 and 50 mg/L DON. In addition, the metabolites 3-epi-DON and the epimer of de-epoxy-DON (3-epi-DOM-1) were found as biotransformation products of both consortia. Our work provides a new valuable tool to screen microbial cultures for their detoxification capacity.

  14. Improving Recommendations in Tag-based Systems with Spectral Clustering of Tag Neighbors

    DEFF Research Database (Denmark)

    Pan, Rong; Xu, Guandong; Dolog, Peter

    2012-01-01

    Tag as a useful metadata reflects the collaborative and conceptual features of documents in social collaborative annotation systems. In this paper, we propose a collaborative approach for expanding tag neighbors and investigate the spectral clustering algorithm to filter out noisy tag neighbors...... in order to get appropriate recommendation for users. The preliminary experiments have been conducted on MovieLens dataset to compare our proposed approach with the traditional collaborative filtering recommendation approach and naive tag neighbors expansion approach in terms of precision, and the result...... demonstrates that our approach could considerably improve the performance of recommendations....

  15. NP-ZBR: An Improved ZBR Routing Algorithm Based on Neighbors Perception

    Directory of Open Access Journals (Sweden)

    Jianli Zhao

    2014-06-01

    Full Text Available ZBR is the most popular routing protocol in ZigBee network currently, but in some cases, it is not very efficient. In this paper a new improved ZBR is proposed which add the network address range field of neighbor node in the neighbor table. So the node can distinguish whether the destination node is the descendants of its neighbor. Compared with the previous protocols OI-ZBR, NI- ZBR and ZBR in NS-2, NP-ZBR shows its merits in the average hop, end to end delay and the first packet delay.

  16. Economic evaluation of health benefits of mercury emission controls for China and the neighboring countries in East Asia

    International Nuclear Information System (INIS)

    Zhang, Wei; Zhen, Gengchong; Chen, Long; Wang, Huanhuan; Li, Ying; Ye, Xuejie; Tong, Yindong; Zhu, Yan; Wang, Xuejun

    2017-01-01

    Globally, coal-fired power plant (CFPP) is a major source of mercury. China is developing its first National Implementation Plan on Mercury Control, which priorities the control of emissions from CFPPs. While social benefits play an important role in designing environmental policies in China, the benefits associated with mercury control are not yet understood, mainly due to the scientific challenges to trace mercury's emissions-to-impacts path. This study evaluates the benefits of mercury reductions in China's CFPPs for China and its three neighboring countries in East Asia. Four policy scenarios are analyzed following the policies-to-impacts path, which links a global atmospheric model to health benefit analysis models to estimate the economic gains from avoided mercury-related adverse health outcomes under each scenario, and take into account key uncertainties in the path. Under the most stringent scenario, the benefits of mercury reduction by 2030 are projected to be $432 billion (95% CI: $166–941 billion), with the benefits for China and the neighboring countries accounting for 96% and 4% of the total benefits, respectively. Policy scenario analysis indicates that coal washing generates the greatest benefits in the near term, whereas upgrading air pollution control devices maximizes health benefits in the long term. - Highlights: • Benefits of mercury controls for China and neighboring countries are analyzed. • Policy analysis shows that coal washing generates the largest benefits in near term. • Upgrading air pollution control devices maximizes health benefits in long term. • For mercury controls, local policies contribute most to local benefits.

  17. Development by flow cytometry of bioassays based on chlorella for environmental monitoring

    Directory of Open Access Journals (Sweden)

    Petrescu C-M,

    2016-05-01

    Full Text Available In ecotoxicological assessments, bioassays (ecotoxicity tests or biotests are one of the main tools, defined as methods which use living cells, tissues, organism or communities to assess exposure-related effects of chemicals. The increasing complexity of environmental degradation requires an increase in the capacity of scientific approach in monitoring and notification as early as possible risks. Our own objective concerns the detection of aquatic environment pollution in Romania and particularly in the Danube basin. For assessing aquatic environment pollution degree or for assessing cytotoxicity or ecotoxicity of pollutants (heavy metals, nanoparticles, pesticides, etc. we developed news experimental bioassays based on the use of viability and apoptosis biomarkers of Chlorella cells by flow cytometry. Our proposed bioassays could be rapid and very sensitive tests for in laboratory aquatic risk assessment and biomonitoring.

  18. Experimental and computational characterization of biological liquid crystals: a review of single-molecule bioassays.

    Science.gov (United States)

    Eom, Kilho; Yang, Jaemoon; Park, Jinsung; Yoon, Gwonchan; Soo Sohn, Young; Park, Shinsuk; Yoon, Dae Sung; Na, Sungsoo; Kwon, Taeyun

    2009-09-10

    Quantitative understanding of the mechanical behavior of biological liquid crystals such as proteins is essential for gaining insight into their biological functions, since some proteins perform notable mechanical functions. Recently, single-molecule experiments have allowed not only the quantitative characterization of the mechanical behavior of proteins such as protein unfolding mechanics, but also the exploration of the free energy landscape for protein folding. In this work, we have reviewed the current state-of-art in single-molecule bioassays that enable quantitative studies on protein unfolding mechanics and/or various molecular interactions. Specifically, single-molecule pulling experiments based on atomic force microscopy (AFM) have been overviewed. In addition, the computational simulations on single-molecule pulling experiments have been reviewed. We have also reviewed the AFM cantilever-based bioassay that provides insight into various molecular interactions. Our review highlights the AFM-based single-molecule bioassay for quantitative characterization of biological liquid crystals such as proteins.

  19. The Radioactive Legacy of the Russian Pacific Fleet Operations and its Potential Impact on Neighboring Countries. Final Report

    International Nuclear Information System (INIS)

    Compton, K. L.; Novikov, V.M.; Parker, F.L.; Sivintsev, Y.U.

    2003-01-01

    There have been extensive studies of the current and potential environmental impact of Russian Northern fleet activities. However, despite the fact that the total number of ships in both fleets are comparable, there have been very few studies published in the open literature of the impact of the Pacific fleet. This study of the Pacific fleet's impact on neighboring countries was undertaken to partially remedy this lack of analysis. This study is focused on an evaluation of the inventory of major sources of radioactive material associated with the decommissioning of nuclear submarines, and an evaluation of releases to the atmosphere and their long-range (>100km) transboundary transport

  20. In vitro bioassays to evaluate complex chemical mixtures in recycled water.

    Science.gov (United States)

    Jia, Ai; Escher, Beate I; Leusch, Frederic D L; Tang, Janet Y M; Prochazka, Erik; Dong, Bingfeng; Snyder, Erin M; Snyder, Shane A

    2015-09-01

    With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, arylhydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection

  1. In vitro bioassays to evaluate complex chemical mixtures in recycled water

    Science.gov (United States)

    Jia, Ai; Escher, Beate I.; Leusch, Frederic D.L.; Tang, Janet Y.M.; Prochazka, Erik; Dong, Bingfeng; Snyder, Erin M.; Snyder, Shane A.

    2016-01-01

    With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, aryl hydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection

  2. Genotoxicity of soil from farmland irrigated with wastewater using three plant bioassays.

    Science.gov (United States)

    Cabrera, G L; Rodriguez, D M

    1999-05-19

    Three well known plant bioassays, the Allium root chromosome aberration (AL-RAA) assay, the Tradescantia micronucleus (Trad-MCN) assay, and the Tradescantia stamen hair (Trad-SHM) mutation assay were validated in 1991 by the International Programme on Chemical Safety (IPCS) under the auspices of the World Health Organization, and the United Nations Environment Programme (UNEP). These plant bioassays have proven to be efficient tests for chemical screening and especially for in situ monitoring for genotoxicity of environmental pollutants. As a result of this validation study, standard protocols of these three plant bioassays were used by some of the 11 participating countries in the IPCS to carry on genotoxicity tests on air, water and soil as a follow up activity. In the city of Queretaro, Mexico, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the farm crops, polluting the soil. Potentially the pollutants could reach the food chain. For the above reason, soil irrigated with wastewater was sampled and monitored for the presence of genotoxic agents using the above three bioassays. Extracts from soil samples were made using distilled water and organic solvents by shaking the sample for about 12 h under a relatively low temperature (15-20 degrees C). Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the extracts. Three replicates of each sample were analyzed in each of the three bioassays. Extracts using DMSO, ethanol and distilled water tested positive in the three bioassays and there were no differences for the genotoxicity of the extracts with the different solvents. Copyright 1999 Elsevier Science B.V.

  3. A Brine Shrimp Bioassay for Measuring Toxicity and Remediation of Chemicals

    Science.gov (United States)

    Lieberman, Marya

    1999-12-01

    A bioassay using Artemia franciscana (brine shrimp) was adapted to measure the toxicity of household chemicals. One project is described in which students collect dose-response curves for seven commercial flea-killing products. Next, groups of students researched the insecticidal ingredients of the flea products. On the basis of the structures of the active ingredients, they chose remediation methods to make the flea product less toxic to brine shrimp; procedures included copper-catalyzed hydrolysis, adsorption onto activated charcoal, bleach treatment, and photodegradation. No special equipment or supplies are necessary for the bioassay other than the brine shrimp eggs, which can be obtained at any aquarium store.

  4. Review of Bioassays for Monitoring Fate and Transport ofEstrogenic Endocrine Disrupting Compounds in Water

    Energy Technology Data Exchange (ETDEWEB)

    CGCampbell@lbl.gov

    2004-01-30

    Endocrine disrupting compounds (EDCs) are recognizedcontaminants threatening water quality. Despite efforts in sourceidentification, few strategies exist for characterization or treatment ofthis environmental pollution. Given that there are numerous EDCs that cannegatively affect humans and wildlife, general screening techniques likebioassays and biosensors provide an essential rapid and intensiveanalysis capacity. Commonly applied bioassays include the ELISA and YESassays, but promising technologies include ER-CALUXa, ELRA, Endotecta,RIANA, and IR-bioamplification. Two biosensors, Endotecta and RIANA, arefield portable using non-cellular biological detection strategies.Environmental management of EDCs in water requires integration ofbiosensors and bioassays for monitoring and assessment.

  5. On Competitiveness of Nearest-Neighbor-Based Music Classification: A Methodological Critique

    DEFF Research Database (Denmark)

    Pálmason, Haukur; Jónsson, Björn Thór; Amsaleg, Laurent

    2017-01-01

    The traditional role of nearest-neighbor classification in music classification research is that of a straw man opponent for the learning approach of the hour. Recent work in high-dimensional indexing has shown that approximate nearest-neighbor algorithms are extremely scalable, yielding results...... of reasonable quality from billions of high-dimensional features. With such efficient large-scale classifiers, the traditional music classification methodology of aggregating and compressing the audio features is incorrect; instead the approximate nearest-neighbor classifier should be given an extensive data...... collection to work with. We present a case study, using a well-known MIR classification benchmark with well-known music features, which shows that a simple nearest-neighbor classifier performs very competitively when given ample data. In this position paper, we therefore argue that nearest...

  6. High-energy physics laboratory reaches out to Chicago-area neighbors

    CERN Multimedia

    Grady, W

    2004-01-01

    "A meeting this weekend with neighbors might be as important to the future of Fermi National Accelerator Laboratory as the improvements in recent years to exotic equipment that sends millions of subatomic particles whizzing through its tunnels" (1 page)

  7. Mixed random walks with a trap in scale-free networks including nearest-neighbor and next-nearest-neighbor jumps

    Science.gov (United States)

    Zhang, Zhongzhi; Dong, Yuze; Sheng, Yibin

    2015-10-01

    Random walks including non-nearest-neighbor jumps appear in many real situations such as the diffusion of adatoms and have found numerous applications including PageRank search algorithm; however, related theoretical results are much less for this dynamical process. In this paper, we present a study of mixed random walks in a family of fractal scale-free networks, where both nearest-neighbor and next-nearest-neighbor jumps are included. We focus on trapping problem in the network family, which is a particular case of random walks with a perfect trap fixed at the central high-degree node. We derive analytical expressions for the average trapping time (ATT), a quantitative indicator measuring the efficiency of the trapping process, by using two different methods, the results of which are consistent with each other. Furthermore, we analytically determine all the eigenvalues and their multiplicities for the fundamental matrix characterizing the dynamical process. Our results show that although next-nearest-neighbor jumps have no effect on the leading scaling of the trapping efficiency, they can strongly affect the prefactor of ATT, providing insight into better understanding of random-walk process in complex systems.

  8. Visitando vizinhos: uma análise da série histórica de produção de bens de capital no Brasil utilizando diagramas de recorrência Encountering neighbors: an analysis of capital goods production in Brazil using recurrence plot diagrams

    Directory of Open Access Journals (Sweden)

    Newton Paulo Bueno

    2009-08-01

    Full Text Available O objetivo do texto é identificar possíveis não linearidades na série de produção de bens de capital brasileira no período janeiro/1975-janeiro/2002. Utilizando a técnica de análise de séries temporais com diagramas de recorrência e o método de previsão por nearest neighbors, apresentam-se evidências de que os investimentos no Brasil - tomando como proxy a série temporal de produção de bens de capital - seguem uma dinâmica com um componente não linear determinístico não desprezível. Embora não tenha sido objetivo do texto identificar a possível fonte dessa dinâmica, os resultados empíricos alcançados autorizam a supor que a dinâmica macroeconômica brasileira pode ser mais sensível à variabilidade da política econômica do que normalmente se supõe. A implicação disso é que a capacidade de prever esses efeitos, com uma margem estatisticamente aceitável de significância, pode ser muito reduzida em períodos em que a dinâmica da série se torna mais sensível em relação às condições iniciais; as técnicas aqui empregadas, entretanto, sugerem que em certa medida é possível, senão prever a evolução dos investimentos, pelo menos identificar os períodos nos quais essa previsão é menos confiável.The objective of the paper is to identify possible non-linearities in Brazilian capital goods production in the period January/1975-January/2002. Using the techniques of recurrence plots diagrams and nearest neighbors forecasting, we found evidences that investments in Brazil present a non negligible non-linear component. Although it has not been the purpose of the paper to identify the possible source of that dynamics, the empiric results found authorize to speculate that the dynamics of some important macroeconomic variables in Brazil might be more sensitive to economic policy variability than it is usually supposed. The implication is that the ability to foresee those effects, within a significant

  9. U.S. bioassay Intercomparison Studies Program at Oak Ridge National Lab

    International Nuclear Information System (INIS)

    Payne, G.F.; Bores, N.; Melton, K.K.; Rankin, J.M.

    1998-06-01

    The Intercomparison Studies Program (ISP) for in-vitro bioassay at Oak Ridge National Laboratory (ORNL) has been in place since May 1991. The ISP was originally created to fill a need in the Radiobioassay area at ORNL, specifically in the areas of Quality Control, Quality Assurance, and Performance Testing. In the beginning, this consisted of two or three laboratories working in a pilot intercomparison program. Once it was determined that this could work effectively, the program began to seek additional members to broaden the scope of the effort. The program became formalized with a quarterly report in January 1992. The ISP currently provides cross-check blind/double-blind samples spiked with known amounts of radioactivity to various Department of Energy (DOE) facilities, universities, and private industry organizations throughout the US. These samples can be packaged according to ORNL procedures (ORNL sample bottles, ORNL chain-of-custody forms, tamper seals etc.), for a single blind sample or according to the needs of a particular facility if the double-blind sample mode is to be maintained. In 1998, the customer base was broadened to include European facilities. In January 1993, the whole-body count program was added. This involves each participating facility receiving a block phantom from the ISP and determining a geometry factor using a known standard. At quarterly intervals, each participant receives an unknown sample for analysis. The sample is counted and the data is collected for publication in an annual report. In October 1994, the fecal program was added. This involves spiking an artificial matrix with known amounts of radioactivity. Laboratories receive unknown samples on a quarterly basis. The sample is counted and the data is collected and published in a quarterly report. The ISP maintains archive samples which can be analyzed in the QC laboratory at the request of any participants if a conflict or discrepancy in a sample analysis/result occurs

  10. Fusarium infection in maize: volatile induction of infected and neighboring uninfected plants has the potential to attract a pest cereal leaf beetle, Oulema melanopus.

    Science.gov (United States)

    Piesik, Dariusz; Lemńczyk, Grzegorz; Skoczek, Agata; Lamparski, Robert; Bocianowski, Jan; Kotwica, Karol; Delaney, Kevin J

    2011-09-01

    Fusarium infection of maize leaves and/or roots through the soil can stimulate the emission of volatile organic compounds (VOCs). It is also well known that VOC emission from maize plants can repel or attract pests. In our experiments, we studied VOC induction responses of Zea mays L. ssp. mays cv. 'Prosna' having Fusarium infection (mix of four species) in leaves or roots, then tested for VOC induction of uninfected neighboring plants, and finally examined wind-tunnel behavioral responses of the adult cereal leaf beetle, Oulema melanopus L. (Chrysomelidae: Coleoptera) behavior to four induced VOCs. In the first part of our experiment, we confirmed that several green leaf volatiles (GLVs; (Z)-3-hexenal, (E)-2-hexenal, (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (Z)-3-hexen-1-yl acetate, 1-hexyl acetate), terpenes (β-pinene, β-myrcene, Z-ocimene, linalool, β-caryophyllene), and shikimic acid pathway derivatives (benzyl acetate, methyl salicylate, indole) were positively induced from maize plants infected by Fusarium spp. The quantities of induced VOCs were higher at 7d than 3d post-infection and greater when plants were infected with Fusarium on leaves rather than through soil. In the second part of our experiment, uninfected maize plants also showed significantly positive induction of several VOCs when neighboring an infected plant where the degree of induction was negatively related to the distance from the infected plant. In the third part of our experiment, a Y-tube bioassay was used to evaluate upwind orientation of adult cereal leaf beetles to four individual VOCs. Female and male O. melanopus were significantly attracted to the GLVs (Z)-3-hexenal and (Z)-3-hexenyl acetate, and the terpenes linalool and β-caryophyllene. Our results indicate that a pathogen can induce several VOCs in maize plants that also induce VOCs in neighboring uninfected plants, though VOC induction could increase the range at which an insect pest species is attracted to VOC inducing plants

  11. Phytotoxicity and Cytotoxicity of Essential Oil from Leaves of Plectranthus amboinicus, Carvacrol, and Thymol in Plant Bioassays.

    Science.gov (United States)

    Pinheiro, Patrícia Fontes; Costa, Adilson Vidal; Alves, Thammyres de Assis; Galter, Iasmini Nicoli; Pinheiro, Carlos Alexandre; Pereira, Alexandre Fontes; Oliveira, Carlos Magno Ramos; Fontes, Milene Miranda Praça

    2015-10-21

    The essential oil of Plectranthus amboinicus and its chemotypes, carvacrol and thymol, were evaluated on the germination and root and aerial growth of Lactuca sativa and Sorghum bicolor and in acting on the cell cycle of meristematic root cells of L. sativa. The main component found in the oil by analysis in gas chromatography-mass spectrometry and gas chromatography flame ionization detection was carvacrol (88.61% in area). At a concentration of 0.120% (w v(-1)), the oil and its chemotypes retarded or inhibited the germination and decreased root and aerial growth in monocot and dicot species used in the bioassays. In addition, all substances caused changes in the cell cycle of the meristematic cells of L. sativa, with chromosomal alterations occurring from the 0.015% (w v(-1)) concentration. The essential oil of P. amboinicus, carvacrol, and thymol have potential for use as bioherbicides.

  12. Virtual screening and repositioning of inconclusive molecules of beta-lactamase Bioassays-A data mining approach.

    Science.gov (United States)

    Gad, Akshata; Manuel, Andrew Titus; K R, Jinuraj; John, Lijo; R, Sajeev; V G, Shanmuga Priya; U C, Abdul Jaleel

    2017-10-01

    This study focuses on the best possible way forward in utilizing inconclusive molecules of PubChem bioassays AID 1332, AID 434987 and AID 434955, which are related to beta-lactamase inhibitors of Mycobacterium tuberculosis (Mtb). The inadequacy in the experimental methods that were observed during the invitro screening resulted in an inconclusive dataset. This could be due to certain moieties present within the molecules. In order to reconsider such molecules, insilico methods can be suggested in place of invitro methods For instance, datamining and medicinal chemistry methods: have been adopted to prioritise the inconclusive dataset into active or inactive molecules. These include the Random Forest algorithm for dataminning, Lilly MedChem rules for virtually screening out the promiscuity, and Self Organizing Maps (SOM) for clustering the active molecules and enlisting them for repositioning through the use of artificial neural networks. These repositioned molecules could then be prioritized for downstream drug discovery analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Retrieving Backbone String Neighbors Provides Insights Into Structural Modeling of Membrane Proteins*

    Science.gov (United States)

    Sun, Jiang-Ming; Li, Tong-Hua; Cong, Pei-Sheng; Tang, Sheng-Nan; Xiong, Wen-Wei

    2012-01-01

    Identification of protein structural neighbors to a query is fundamental in structure and function prediction. Here we present BS-align, a systematic method to retrieve backbone string neighbors from primary sequences as templates for protein modeling. The backbone conformation of a protein is represented by the backbone string, as defined in Ramachandran space. The backbone string of a query can be accurately predicted by two innovative technologies: a knowledge-driven sequence alignment and encoding of a backbone string element profile. Then, the predicted backbone string is employed to align against a backbone string database and retrieve a set of backbone string neighbors. The backbone string neighbors were shown to be close to native structures of query proteins. BS-align was successfully employed to predict models of 10 membrane proteins with lengths ranging between 229 and 595 residues, and whose high-resolution structural determinations were difficult to elucidate both by experiment and prediction. The obtained TM-scores and root mean square deviations of the models confirmed that the models based on the backbone string neighbors retrieved by the BS-align were very close to the native membrane structures although the query and the neighbor shared a very low sequence identity. The backbone string system represents a new road for the prediction of protein structure from sequence, and suggests that the similarity of the backbone string would be more informative than describing a protein as belonging to a fold. PMID:22415040

  14. Retrieving backbone string neighbors provides insights into structural modeling of membrane proteins.

    Science.gov (United States)

    Sun, Jiang-Ming; Li, Tong-Hua; Cong, Pei-Sheng; Tang, Sheng-Nan; Xiong, Wen-Wei

    2012-07-01

    Identification of protein structural neighbors to a query is fundamental in structure and function prediction. Here we present BS-align, a systematic method to retrieve backbone string neighbors from primary sequences as templates for protein modeling. The backbone conformation of a protein is represented by the backbone string, as defined in Ramachandran space. The backbone string of a query can be accurately predicted by two innovative technologies: a knowledge-driven sequence alignment and encoding of a backbone string element profile. Then, the predicted backbone string is employed to align against a backbone string database and retrieve a set of backbone string neighbors. The backbone string neighbors were shown to be close to native structures of query proteins. BS-align was successfully employed to predict models of 10 membrane proteins with lengths ranging between 229 and 595 residues, and whose high-resolution structural determinations were difficult to elucidate both by experiment and prediction. The obtained TM-scores and root mean square deviations of the models confirmed that the models based on the backbone string neighbors retrieved by the BS-align were very close to the native membrane structures although the query and the neighbor shared a very low sequence identity. The backbone string system represents a new road for the prediction of protein structure from sequence, and suggests that the similarity of the backbone string would be more informative than describing a protein as belonging to a fold.

  15. Male song sparrows have elevated testosterone in response to neighbors versus strangers.

    Science.gov (United States)

    Moser-Purdy, Christopher; MacDougall-Shackleton, Scott A; Bonier, Frances; Graham, Brendan A; Boyer, Andrea C; Mennill, Daniel J

    2017-07-01

    Upon hearing a conspecific signal, animals must assess their relationship with the signaller and respond appropriately. Territorial animals usually respond more aggressively to strangers than neighbors in a phenomenon known as the "dear enemy effect". This phenomenon likely evolved because strangers represent a threat to an animal's territory tenure and parentage, whereas neighbors only represent a threat to an animal's parentage because they already possess a territory (providing territory boundaries are established and stable). Although the dear enemy effect has been widely documented using behavioral response variables, little research has been conducted on the physiological responses of animals to neighbors versus strangers. We sought to investigate whether the dear enemy effect is observed physiologically by exposing territorial male song sparrows (Melospiza melodia) to playback simulating a neighbor or a stranger, and then collecting blood samples to measure plasma testosterone levels. We predicted that song sparrows would exhibit increased testosterone levels after exposure to stranger playback compared to neighbor playback, due to the role testosterone plays in regulating aggression. Contrary to our prediction, we found that song sparrows had higher testosterone levels after exposure to neighbor playback compared to stranger playback. We discuss several explanations for our result, notably that corticosterone may regulate the dear enemy effect in male song sparrows and this may inhibit plasma testosterone. Future studies will benefit from examining corticosterone in addition to testosterone, to better understand the hormonal underpinnings of the dear enemy effect. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. High-throughput mosquito and fly bioassay system for natural and artificial substrates treated with residual insecticides.

    Science.gov (United States)

    Aldridge, Robert L; Wynn, W Wayne; Britch, Seth C; Allan, Sandra A; Walker, Todd W; Geden, Christopher J; Hogsette, Jerome A; Linthicum, Kenneth J

    2013-03-01

    A high-throughput bioassay system to evaluate the efficacy of residual pesticides against mosquitoes and muscid flies with minimal insect handling was developed. The system consisted of 4 components made of readily available materials: 1) a CO2 anaesthetizing chamber, 2) a specialized aspirator, 3) a cylindrical flat-bottomed glass bioassay chamber assembly, and 4) a customized rack.

  17. Screening for the presence of lipophilic marine biotoxins in shellfish samples using the neuro-2a bioassay

    NARCIS (Netherlands)

    Bodero Baeza, Marcia; Bovee, Toine F.H.; Wang, S.; Hoogenboom, Ron L.A.P.; Klijnstra, Mirjam D.; Portier, Liza; Hendriksen, Peter J.M.; Gerssen, Arjen

    2018-01-01

    The neuro-2a bioassay is considered as one of the most promising cell-based in vitro bioassays for the broad screening of seafood products for the presence of marine biotoxins. The neuro-2a assay has been shown to detect a wide array of toxins like paralytic shellfish poisons (PSPs), ciguatoxins,

  18. Dominican and Haitian Neighbors: Making Moral Attitudes and Working Relationships in the Banana Bateyes

    Directory of Open Access Journals (Sweden)

    Kimberly Wynne

    2016-04-01

    Full Text Available Este artículo responde a la necesidad de explorar cómo el acto de equilibrio del estado Dominicano, sujeto a la demanda económica de mano de obra inmigrante, por un lado, y a la presión política que exige la exclusión de los haitianos de la sociedad dominicana, por el otro, es negociado localmente. Con base en investigación etnográfica en comunidades bananeras llamadas bateyes, este artículo presenta un análisis de las respuestas locales a los cambios causados por la llegada de un creciente número de inmigrantes haitianos. Aun cuando los inmigrantes haitianos son considerados necesarios para la producción bananera, el coexistir con ellos genera incertidumbres sobre violencia e identidad entre los dominicanos. Este artículo argumenta que los residentes dominicanos hacen frente a estos sentimientos de incertidumbre mediante la cultivación de una aparente superioridad moral sobre sus vecinos haitianos. Finalmente, este artículo sugiere que las prácticas de los dominicanos, quienes luchan por ganarse la vida a la par de sus vecinos haitianos, revelan una relación complicada no sólo por la existencia de una ideología anti-haitiana, pero por una vida precaria, históricamente construida, que marginaliza a los residentes de los bateyes en su conjunto. English: This article addresses the need to explore how the Dominican state’s ongoing balancing act between the economic demand for migrant workers and the political pressure to exclude Haitians from Dominican society is negotiated locally. Based on ethnographic research conducted in banana-growing communities called 'bateyes', this article provides an analysis of local responses to changes occurring with the arrival of increasingly more Haitian residents. While Haitian migrants are regarded as necessary for banana production, living among them triggers insecurities about violence and identity among Dominicans. The article argues that Dominican residents cope with these feelings of

  19. Assessment of sediment toxicity in the Lagoon of Venice (Italy) using a multi-species set of bioassays.

    Science.gov (United States)

    Picone, Marco; Bergamin, Martina; Losso, Chiara; Delaney, Eugenia; Arizzi Novelli, Alessandra; Ghirardini, Annamaria Volpi

    2016-01-01

    Within the framework of a Weight of Evidence (WoE) approach, a set of four toxicity bioassays involving the amphipod Corophium volutator (10 d lethality test on whole sediment), the sea urchin Paracentrotus lividus (fertilization and embryo toxicity tests on elutriate) and the pacific oyster Crassostrea gigas (embryo toxicity test on elutriate) was applied to sediments from 10 sampling sites of the Venice Lagoon (Italy). Sediments were collected during three campaigns carried out in May 2004 (spring campaign), October 2004 (autumn campaign) and February 2005 (winter campaign). Toxicity tests were performed on all sediment samples. Sediment grain-size and chemistry were measured during spring and autumn campaigns. This research investigated (i) the ability of toxicity tests in discriminating among sites with different contamination level, (ii) the occurrence of a gradient of effect among sampling sites, (iii) the possible correlation among toxicity tests, sediment chemistry, grain size and organic carbon, and (iv) the possible occurrence of toxicity seasonal variability. Sediment contamination levels were from low to moderate. No acute toxicity toward amphipods was observed, while sea urchin fertilization was affected only in few sites in just a single campaign. Short-term effects on larval development of sea urchin and oyster evidenced a clear spatial trend among sites, with increasing effects along the axis connecting the sea-inlets with the industrial area. The set of bioassays allowed the identification of a spatial gradient of effect, with decreasing toxicity from the industrial area toward the sea-inlets. Multivariate data analysis showed that the malformations of oyster embryos were significantly correlated to the industrial contamination (metals, polynuclear aromatic hydrocarbons, hexachlorobenzene and polychlorinated biphenyls), while sea urchin development to sediment concentrations of As, Cr and organic carbon. Both embryo toxicity tests were

  20. Nearest-neighbor interaction systems in the tensor-train format

    Science.gov (United States)

    Gelß, Patrick; Klus, Stefan; Matera, Sebastian; Schütte, Christof

    2017-07-01

    Low-rank tensor approximation approaches have become an important tool in the scientific computing community. The aim is to enable the simulation and analysis of high-dimensional problems which cannot be solved using conventional methods anymore due to the so-called curse of dimensionality. This requires techniques to handle linear operators defined on extremely large state spaces and to solve the resulting systems of linear equations or eigenvalue problems. In this paper, we present a systematic tensor-train decomposition for nearest-neighbor interaction systems which is applicable to a host of different problems. With the aid of this decomposition, it is possible to reduce the memory consumption as well as the computational costs significantly. Furthermore, it can be shown that in some cases the rank of the tensor decomposition does not depend on the network size. The format is thus feasible even for high-dimensional systems. We will illustrate the results with several guiding examples such as the Ising model, a system of coupled oscillators, and a CO oxidation model.

  1. Spatiotemporal distribution of Oklahoma earthquakes: Exploring relationships using a nearest-neighbor approach

    Science.gov (United States)

    Vasylkivska, Veronika S.; Huerta, Nicolas J.

    2017-07-01

    Determining the spatiotemporal characteristics of natural and induced seismic events holds the opportunity to gain new insights into why these events occur. Linking the seismicity characteristics with other geologic, geographic, natural, or anthropogenic factors could help to identify the causes and suggest mitigation strategies that reduce the risk associated with such events. The nearest-neighbor approach utilized in this work represents a practical first step toward identifying statistically correlated clusters of recorded earthquake events. Detailed study of the Oklahoma earthquake catalog's inherent errors, empirical model parameters, and model assumptions is presented. We found that the cluster analysis results are stable with respect to empirical parameters (e.g., fractal dimension) but were sensitive to epicenter location errors and seismicity rates. Most critically, we show that the patterns in the distribution of earthquake clusters in Oklahoma are primarily defined by spatial relationships between events. This observation is a stark contrast to California (also known for induced seismicity) where a comparable cluster distribution is defined by both spatial and temporal interactions between events. These results highlight the difficulty in understanding the mechanisms and behavior of induced seismicity but provide insights for future work.

  2. Testing spatial symmetry using contingency tables based on nearest neighbor relations.

    Science.gov (United States)

    Ceyhan, Elvan

    2014-01-01

    We consider two types of spatial symmetry, namely, symmetry in the mixed or shared nearest neighbor (NN) structures. We use Pielou's and Dixon's symmetry tests which are defined using contingency tables based on the NN relationships between the data points. We generalize these tests to multiple classes and demonstrate that both the asymptotic and exact versions of Pielou's first type of symmetry test are extremely conservative in rejecting symmetry in the mixed NN structure and hence should be avoided or only the Monte Carlo randomized version should be used. Under RL, we derive the asymptotic distribution for Dixon's symmetry test and also observe that the usual independence test seems to be appropriate for Pielou's second type of test. Moreover, we apply variants of Fisher's exact test on the shared NN contingency table for Pielou's second test and determine the most appropriate version for our setting. We also consider pairwise and one-versus-rest type tests in post hoc analysis after a significant overall symmetry test. We investigate the asymptotic properties of the tests, prove their consistency under appropriate null hypotheses, and investigate finite sample performance of them by extensive Monte Carlo simulations. The methods are illustrated on a real-life ecological data set.

  3. A pattern-based nearest neighbor search approach for promoter prediction using DNA structural profiles.

    Science.gov (United States)

    Gan, Yanglan; Guan, Jihong; Zhou, Shuigeng

    2009-08-15

    Identification of core promoters is a key clue in understanding gene regulations. However, due to the diverse nature of promoter sequences, the accuracy of existing prediction approaches for non-CpG island (simply CGI)-related promoters is not as high as that for CGI-related promoters. This consequently leads to a low genome-wide promoter prediction accuracy. In this article, we first systematically analyze the similarities and differences between the two types of promoters (CGI- and non-CGI-related) from a novel structural perspective, and then devise a unified framework, called PNNP (Pattern-based Nearest Neighbor search for Promoter), to predict both CGI- and non-CGI-related promoters based on their structural features. Our comparative analysis on the structural characteristics of promoters reveals two interesting facts: (i) the structural values of CGI- and non-CGI-related promoters are quite different, but they exhibit nearly similar structural patterns; (ii) the structural patterns of promoters are obviously different from that of non-promoter sequences though the sequences have almost similar structural values. Extensive experiments demonstrate that the proposed PNNP approach is effective in capturing the structural patterns of promoters, and can significantly improve genome-wide performance of promoters prediction, especially non-CGI-related promoters prediction. The implementation of the program PNNP is available at http://admis.tongji.edu.cn/Projects/pnnp.aspx.

  4. Heterogeneous autoregressive model with structural break using nearest neighbor truncation volatility estimators for DAX.

    Science.gov (United States)

    Chin, Wen Cheong; Lee, Min Cherng; Yap, Grace Lee Ching

    2016-01-01

    High frequency financial data modelling has become one of the important research areas in the field of financial econometrics. However, the possible structural break in volatile financial time series often trigger inconsistency issue in volatility estimation. In this study, we propose a structural break heavy-tailed heterogeneous autoregressive (HAR) volatility econometric model with the enhancement of jump-robust estimators. The breakpoints in the volatility are captured by dummy variables after the detection by Bai-Perron sequential multi breakpoints procedure. In order to further deal with possible abrupt jump in the volatility, the jump-robust volatility estimators are composed by using the nearest neighbor truncation approach, namely the minimum and median realized volatility. Under the structural break improvements in both the models and volatility estimators, the empirical findings show that the modified HAR model provides the best performing in-sample and out-of-sample forecast evaluations as compared with the standard HAR models. Accurate volatility forecasts have direct influential to the application of risk management and investment portfolio analysis.

  5. AHNAK enables mammary carcinoma cells to produce extracellular vesicles that increase neighboring fibroblast cell motility.

    Science.gov (United States)

    Silva, Thaiomara A; Smuczek, Basílio; Valadão, Iuri C; Dzik, Luciana M; Iglesia, Rebeca P; Cruz, Mário C; Zelanis, André; de Siqueira, Adriane S; Serrano, Solange M T; Goldberg, Gary S; Jaeger, Ruy G; Freitas, Vanessa M

    2016-08-02

    Extracellular vesicles play important roles in tumor development. Many components of these structures, including microvesicles and exosomes, have been defined. However, mechanisms by which extracellular vesicles affect tumor progression are not fully understood. Here, we investigated vesicular communication between mammary carcinoma cells and neighboring nontransformed mammary fibroblasts. Nonbiased proteomic analysis found that over 1% of the entire proteome is represented in these vesicles, with the neuroblast differentiation associated protein AHNAK and annexin A2 being the most abundant. In particular, AHNAK was found to be the most prominent component of these vesicles based on peptide number, and appeared necessary for their formation. In addition, we report here that carcinoma cells produce vesicles that promote the migration of recipient fibroblasts. These data suggest that AHNAK enables mammary carcinoma cells to produce and release extracellular vesicles that cause disruption of the stroma by surrounding fibroblasts. This paradigm reveals fundamental mechanisms by which vesicular communication between carcinoma cells and stromal cells can promote cancer progression in the tumor microenvironment.

  6. UV-C-irradiated Arabidopsis and tobacco emit volatiles that trigger genomic instability in neighboring plants.

    Science.gov (United States)

    Yao, Youli; Danna, Cristian H; Zemp, Franz J; Titov, Viktor; Ciftci, Ozan Nazim; Przybylski, Roman; Ausubel, Frederick M; Kovalchuk, Igor

    2011-10-01

    We have previously shown that local exposure of plants to stress results in a systemic increase in genome instability. Here, we show that UV-C-irradiated plants produce a volatile signal that triggers an increase in genome instability in neighboring nonirradiated Arabidopsis thaliana plants. This volatile signal is interspecific, as UV-C-irradiated Arabidopsis plants transmit genome destabilization to naive tobacco (Nicotiana tabacum) plants and vice versa. We report that plants exposed to the volatile hormones methyl salicylate (MeSA) or methyl jasmonate (MeJA) exhibit a similar level of genome destabilization as UV-C-irradiated plants. We also found that irradiated Arabidopsis plants produce MeSA and MeJA. The analysis of mutants impaired in the synthesis and/or response to salicylic acid (SA) and/or jasmonic acid showed that at least one other volatile compound besides MeSA and MeJA can communicate interplant genome instability. The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (npr1) mutant, defective in SA signaling, is impaired in both the production and the perception of the volatile signals, demonstrating a key role for NPR1 as a central regulator of genome stability. Finally, various forms of stress resulting in the formation of necrotic lesions also generate a volatile signal that leads to genomic instability.

  7. Practical issues in discriminating between environmental and occupational sources in a uranium urinalysis bioassay program

    International Nuclear Information System (INIS)

    Long, M.P.; Carbaugh, E.H.; Fairrow, N.L.

    1994-11-01

    Workers at two Department of Energy facilities, the Pantex Plant in Texas and the Hanford Site in Washington, are potentially exposed to class Y depleted or natural uranium. Since trace amounts of uranium are naturally present in urine excretion, site bioassay programs must be able to discern occupational exposure from naturally occurring uranium exposure. In 1985 Hanford established a 0.2-μg/d environmental screening level for elemental uranium in urine; the protocol was based on log-normal probability analysis of unexposed workers. A second study of background uranium levels commenced in 1990, and experiences in the field indicated that there seemed to be an excessive number of urine samples with uranium above the screening level and that the environmental screening level should be reviewed. Due to unforeseen problems, that second study was terminated before the complete data could be obtained. Natural uranium in rock (by weight, 99.27% 288 U, 0.72% 235 U, and 0.006% 234 U) has approximately equal activity concentrations of 238 U and 234 U. Earlier studies, summarized by the U.S. Environmental Protection Agency in 51 FR 32068, have indicated that 234 U (via 234 Th) has a greater environmental mobility than 238 U and may well have a higher concentration in ground water. By assuming that the 238 U-to 234 U ratio in the urine of nonoccupationally exposed persons should reflect the ratio of environmental levels, significant occupational exposure to depleted uranium would shift that ratio in favor of 238 U, allowing use of the ratio as a co-indicator of occupational exposure in addition to the isotope-specific screening levels. This approach has been adopted by Pantex. The Pacific Northwest Laboratory is studying the feasibility of applying this method to the natural and recycled uranium mixtures encountered at Hanford. The Hanford data included in this report represent work-in-progress

  8. Getting ready for the manned mission to Mars: bioassays for space research

    Science.gov (United States)

    Baumstark-Khan, Christa; Hellweg, Christine E.; Arenz, Andrea; Meier, Matthias M.; Horneck, Gerda

    2004-06-01

    Harmful environmental factors - namely ionizing radiation - will continue to influence future manned space missions. The Cellular Biodiagnostic group at the German Aerospace Center (DLR) develops cellular monitoring systems, which include bacterial and mammalian cell systems capable of recognizing DNA damage as a consequence of the presence of genotoxic conditions. Such bioassay or biosensor systems will complement the physical detector systems used in space, insofar as they yield intrinsically biologically weighted measures of cellular responses. Furthermore, synergistic mutagenic and cancerogenic impacts of the radiation environment together with other potentially genotoxic constituents of the space habitat can be quantified using such systems, whose signals are especially relevant for the molecular damage to the DNA or the chromosomes. The experiment Cellular Responses to Radiation in Space (CERASP) has been selected by NASA to be performed on the International Space Station. It will supply basic information on the cellular response to radiation applied in microgravity. One of the biological end-points under investigation will be survival reflected by radiation-dependent reduction of constitutive expression of the enhanced variant of green fluorescent protein (EGFP), originally isolated from the bioluminescent jellyfish Aequorea victoria. A second end-point will be gene activation by space flight conditions in mammalian cells, based on fluorescent promoter reporter systems using the destabilized EGFP variant (d2EGFP). The promoter element to be investigated will reflect the activity of the NF-kappaB stress response pathway as an anti-apoptotic radiation response. DNA damage will be measured by fluorescent analysis of DNA unwinding (FADU). The systems have worked properly for terrestrial applications during the first experiments. Experiments using accelerated particles produced at the French heavy ion accelerator GANIL have given insights into cellular mechanisms

  9. Chip-Scale Bioassays Based on Surface-Enhanced Raman Scattering: Fundamentals and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hye-Young [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    This work explores the development and application of chip-scale bioassays based on surface-enhanced Raman scattering (SERS) for high throughput and high sensitivity analysis of biomolecules. The size effect of gold nanoparticles on the intensity of SERS is first presented. A sandwich immunoassay was performed using Raman-labeled immunogold nanoparticles with various sizes. The SERS responses were correlated to particle densities, which were obtained by atomic force microscopy (AFM). The response of individual particles was also investigated using Raman-microscope and an array of gold islands on a silicon substrate. The location and the size of individual particles were mapped using AFM. The next study describes a low-level detection of Escherichia coli 0157:H7 and simulants of biological warfare agents in a sandwich immunoassay format using SERS labels, which have been termed Extrinsic Raman labels (ERLs). A new ERL scheme based on a mixed monolayer is also introduced. The mixed monolayer ERLs were created by covering the gold nanoparticles with a mixture of two thiolates, one thiolate for covalently binding antibody to the particle and the other thiolate for producing a strong Raman signal. An assay platform based on mixed self-assembled monolayers (SAMs) on gold is then presented. The mixed SAMs were prepared from dithiobis(succinimidyl undecanoate) (DSU) to covalently bind antibodies on gold substrate and oligo(ethylene glycol)-terminated thiol to prevent nonspecific adsorption of antibodies. After the mixed SAMs surfaces, formed from various mole fraction of DSU were incubated with antibodies, AFM was used to image individual antibodies on the surface. The final study presents a collaborative work on the single molecule adsorption of YOYO-I labeled {lambda}-DNA at compositionally patterned SAMs using total internal reflection fluorescence microscopy. The role of solution pH, {lambda}-DNA concentration, and domain size was investigated. This work also revealed

  10. Chemically induced immunotoxicity in a medium-term multiorgan bioassay for carcinogenesis with Wistar rats

    International Nuclear Information System (INIS)

    Spinardi-Barbisan, Ana Lucia Tozzi; Kaneno, Ramon; Barbisan, Luis Fernando; Viana de Camargo, Joao Lauro; Rodrigues, Maria Aparecida Marchesan

    2004-01-01

    A variety of chemicals can adversely affect the immune system and influence tumor development. The modifying potential of chemical carcinogens on the lymphoid organs and cytokine production of rats submitted to a medium-term initiation-promotion bioassay for carcinogenesis was investigated. Male Wistar rats were sequentially initiated with N-nitrosodiethylamine (DEN), N-methyl-N-nitrosourea (MNU), N-butyl-N-(4hydroxybutyl)nitrosamine (BBN), dihydroxy-di-n-propylnitrosamine (DHPN), and 1,2-dimethylhydrazine (DMH) during 4 weeks. Two initiated groups received phenobarbital (PB) or 2-acetylaminofluorene (2-AAF) for 25 weeks and two noninitiated groups received only PB or 2-AAF. A nontreated group was used as control. Lymphohematopoietic organs, liver, kidneys, lung, intestines, and Zymbal's gland were removed for histological analysis. Interleukin (IL)-2, IL-12, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-10, and transforming growth factor beta1 (TGF-β1) levels were determined by ELISA in spleen cell culture supernatants. At the fourth week, exposure to the initiating carcinogens resulted in cell depletion of the thymus, spleen and bone marrow, and impairment of IL-2, IL-12, and IFN-γ production. However, at the 30th week, no important alterations were observed both in lymphoid organs and cytokine production in the different groups. The results indicate that the initiating carcinogens used in the present protocol exert toxic effects on the lymphoid organs and affect the production of cytokines at the initiation step of carcinogenesis. This early and reversible depression of the immune surveillance may contribute to the survival of initiated cells facilitating the development of future neoplasia

  11. Olfactoryresponse of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays

    Science.gov (United States)

    The response of Typhlodromus pyri, a key predator of grapevine rust mite (Calepitrimerus vitis), to MeSA was tested using a Y-tube olfactometer in laboratory bioassays. Six doses ranging from 200 to 0.002 µg of diluted MeSA were tested. Significantly higher proportions of T. pyri preferred MeSA at ...

  12. Sensitivity and Specificity of Bioassay of Estrogenicity on Mammary Gland and Uterus of Female Mice

    Czech Academy of Sciences Publication Activity Database

    Škarda, Josef

    2002-01-01

    Roč. 51, - (2002), s. 407-412 ISSN 0862-8408 R&D Projects: GA ČR GA523/99/0843; GA AV ČR KSK5020115 Institutional research plan: CEZ:AV0Z5045916 Keywords : Bioassay * Estrogenicity * Mammary gland Subject RIV: ED - Physiology Impact factor: 0.984, year: 2002

  13. BIOASSAY STUDIES OF METAL(II) COMPLEXES OF 2,2'-(ETHANE ...

    African Journals Online (AJOL)

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    diyldiimino)diacetic acid (EDDA) were prepared and characterized. Coordination complexes of the EDDA ... corresponding amines with alkyl halide to bear diammines of the same class with different substituents. ... Bioassay studies of metal(II) complexes of 2,2'-(ethane-1,2-diyldiimino)diacetic acid. Bull. Chem. Soc. Ethiop.

  14. Androgen Bioassay for the Detection of Nonlabeled Androgenic Compounds in Nutritional Supplements.

    Science.gov (United States)

    Cooper, Elliot R; McGrath, Kristine C Y; Li, XiaoHong; Heather, Alison K

    2018-01-01

    Both athletes and the general population use nutritional supplements. Athletes often turn to supplements hoping that consuming the supplement will help them be more competitive and healthy, while the general population hopes to improve body image or vitality. While many supplements contain ingredients that may have useful properties, there are supplements that are contaminated with compounds that are banned for use in sport or have been deliberately adulterated to fortify a supplement with an ingredient that will produce the advertised effect. In the present study, we have used yeast cell and mammalian cell androgen bioassays to characterize the androgenic bioactivity of 112 sports supplements available from the Australian market, either over the counter or via the Internet. All 112 products did not declare an androgen on the label as an included ingredient. Our findings show that six out of 112 supplements had strong androgenic bioactivity in the yeast cell bioassay, indicating products spiked or contaminated with androgens. The mammalian cell bioassay confirmed the strong androgenic bioactivity of five out of six positive supplements. Supplement 6 was metabolized to weaker androgenic bioactivity in the mammalian cells. Further to this, Supplement 6 was positive in a yeast cell progestin bioassay. Together, these findings highlight that nutritional supplements, taken without medical supervision, could expose or predispose users to the adverse consequences of androgen abuse. The findings reinforce the need to increase awareness of the dangers of nutritional supplements and highlight the challenges that clinicians face in the fast-growing market of nutritional supplements.

  15. New in vitro reporter gene bioassays for screening of hormonal active compounds in the environment

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Kateřina; Cajthaml, Tomáš

    2010-01-01

    Roč. 88, č. 4 (2010), s. 839-847 ISSN 0175-7598 R&D Projects: GA ČR GAP503/10/0408 Institutional research plan: CEZ:AV0Z50200510 Keywords : endocrine disruptors * in vitro bioassays * reporter gene assays Subject RIV: EE - Microbiology, Virology Impact factor: 3.280, year: 2010

  16. Rapid Bioassessment and In Situ Bioassay: Cost Effective Tools for Environmental Impact Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L.D.

    2002-08-23

    Environmental impact can be difficult to assess, especially at the ecosystem level. Any impact assessment methodology that can give cost effective and timely results is highly desirable. Rapid bioassessment (RBA) is cost effective and produces timely results. Several types of RBA have been used at the Savannah River Site (SRS) to assess stream conditions, including the Index of Biotic Integrity (IBI) based on fish community characteristics, and various techniques using aquatic macroinvertebrate species diversity and abundance. In an attempt to broaden the applicability of the RBA concept, we have also begun to develop RBA techniques for seep-fed wetlands and terrestrial habitats. These techniques will focus on vertebrate and macroinvertebrate assemblages for seep-fed wetlands and arthropod assemblages for terrestrial habitats. In situ bioassay is another technique that could be used for rapid and economical assessment of the effects of anthropogenic disturbance. We propose the development of two methods of in situ bioassay that can address bioavailability of constituents of concern. The use of caged bioassay organisms can be applied to terrestrial systems such as capped or existing waste sites using the common house cricket. Another proposed bioassay could use a resident species, such as the imported red fire ant, which is found in disturbed habitats and open areas such as waste sites. Combining in situ techniques with RBA methodologies has the potential to provide a comprehensive assessment of chemical and physical impacts to a wide range of ecosystem types.

  17. Experience with NQA-1 quality assurance standards applied to in vitro bioassay

    International Nuclear Information System (INIS)

    Bihl, D.E.; MacLellan, J.A.

    1991-10-01

    On June 1, 1990, the large (about 4000 samples per year) excreta bioassay program at the Hanford Site ceased abruptly when the contract with the bioassay laboratory was terminated. An intense, high-priority effort was begun to replace the services on an interim basis until a new contract could be procured. Despite the urgency to get the excreta bioassay program going again, the Hanford Internal Dosimetry Program was constrained to use only labs that could meet stringent quality assurance (QA) requirements, even during the interim period. The QA requirements were based on NQA-1 with selected additions from the Environmental Protection Agency's QAMS 005/80 (EPA 1983) and the American Society for Testing and Materials' C 1009-83 (ASTM 1984). This constraint was driven both by legal reasons and by the Hanford Site contractors and workers not wanting the quality of the data to be sacrificed. Finding labs that could (1) handle the large throughput, (2) meet the technical requirements, and (3) pass the QA audit proved more difficult than first anticipated. This presentation focuses on the QA requirements that the labs had to meet and how those very broad requirements were applied specifically to excreta bioassay. 5 refs

  18. Simple, Inexpensive, and Rapid Way to Produce Bacillus subtilis Spores for the Guthrie Bioassay

    Science.gov (United States)

    Franklin, Martha L.; Clark, William A.

    1981-01-01

    Esculin agar has been found to be a simple, inexpensive, rapid, and reliable means to promote production of spores of inhibitor-sensitive clones of Bacillus subtilis strains ATCC 6051 and 6633 for use in the Guthrie bioassay screening tests for genetic metabolic disorders. Images PMID:6790564

  19. A fluorescence-based bioassay for antibacterials and its application in screening natural product extracts

    NARCIS (Netherlands)

    Michels, Katharina; Heinke, Ramona; Schöne, Pia; Kuipers, Oscar P; Arnold, Norbert; Wessjohann, Ludger A

    2015-01-01

    The reliable assessment of the biological activity of a minor component embedded in a complex matrix of several hundred compounds is a difficult but common task in the search for natural product-based antibiotics, for example, by bioassay-guided fractionation. To quantify the antibiotic properties,

  20. Bioassays for Evaluating Water Quality: Screening for total bioactivity to assess water safety

    Science.gov (United States)

    Bioassays are a potential solution for assessing complex samples since they screen for total bioactivity for a given pathway or mode of action (MOA), such as estrogen receptor activation, in the samples. Overall, they can account for the three challenges listed above, and can sim...

  1. Rapid diagnosis of imazapic & imazapyr resistance by using bioassays in Clearfield Production System, Malaysia

    Science.gov (United States)

    Bajrai F. S., M.; Ismail B., S.; Mardiana-Jansar, Khairiatul

    2015-09-01

    The resistance of weedy rice biotypes toward OnDuty™WG has been reported in Clearfield® MR 220 CL1 and MR 220 CL2 types of paddy. The purpose of this study was to adopt a rapid method to evaluate the resistance of bioassay species towards imazapic + imazapyr in different stages of plant development (seeds and seedlings). A series of OnDuty™WG concentrations from 0 to 300 g ai ha-1 were studied on the growth of rice cultivar MR263 (a susceptible species) as the bioassay species. The experiments were done in three replications with Complete Randomized Block Design (CRBD). From this study, the concentration of herbicide required to reduce coleoptiles length, root length and fresh weight in seed bioassay by 50% were 0.63, 0.33 and 3.60 g ai ha-1 respectively. Meanwhile, for seedling stage bioassay, the concentration of herbicide required to reduce coleoptiles length, root length and fresh weight by 50% were 0.03, 1.23 and 0.99 g ai ha-1 respectively. It is important to note that all growth parameters were concentration dependent and a total growth inhibition occurred in all parameters at high doses. It was proven that MR263 rice cultivar was not resistance towards imazapic + imazapyr and further experiments on other rice cultivars are recommended so that the most suitable cultivars will be selected in rice cultivation.

  2. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    Science.gov (United States)

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  3. Determining UV Inactivation of Toxoplasma gondii Oocysts by Using Cell Culture and a Mouse Bioassay

    Science.gov (United States)

    The effect of UV exposure on Toxoplasma gondii oocysts has not been completely defined for use in water disinfection. This study evaluated UV irradiated oocysts by three assays: a SCID mouse bioassay, an in vitro T. gondii oocyst plaque assay (TOP-assay), and a quantitative reve...

  4. Evaluation of soil bioassays for use at Washington state hazardous waste sites: A pilot study

    International Nuclear Information System (INIS)

    Blakley, N.; Norton, D.; Stinson, M.; Boyer, R.

    1994-01-01

    The Washington State Department of Ecology (Ecology) is developing guidelines to assess soil toxicity at hazardous waste sites being investigated under the Washington Model Toxics Control Act Cleanup Regulation. To evaluate soil toxicity, Ecology selected five bioassay protocols -- Daphnia, Earthworm, Seedling, Fathead Minnow, and Frog Embryo Teratogenesis Assay Xenopus (FETAX) -- for use as screening level assessment tools at six State hazardous waste sites. Sites contained a variety of contaminants including metals, creosote, pesticides, and petroleum products (leaking underground storage tanks). Three locations, representing high, medium, and low levels of contamination, were samples at each site. In general, the high contaminant samples resulted in the highest toxic response in all bioassays. The order of site toxicity, as assessed by overall toxic response, is creosote, petroleum products, metals, and pesticides. Results indicate that human health standards, especially for metals, may not adequately protect some of the species tested. The FETAX bioassay had the greatest overall number of toxic responses and lowest variance. The seedling and Daphnia bioassays had lower and similar overall toxic response results, followed by the earthworm and fathead minnow. Variability was markedly highest for the seedling. The Daphnia and fathead minnow variability were similar to the FETAX level, while the earthworm variability was slightly higher

  5. A Paradigm for Developing Sediment Toxicity Bioassays for the Regulatory Evaluation of Dredged Material

    Science.gov (United States)

    1994-06-01

    dredging program and has direct application to the develop- meat of sediment toxicity bioassays. Federal statutes (MPRSA and CWA) require "no...assessing interspecific differences in xenobiotic metab- olism for major contaminants. Cost and logistics. By this point, the technical community should

  6. Development of a bioassay system for human growth hormone determination with close correlation to immunoassay.

    Science.gov (United States)

    Maimaiti, M; Tanahashi, Y; Mohri, Z; Fujieda, K

    2012-09-01

    Serum growth hormone (GH) level is measured largely through immunoassays in clinical practice. However, a few cases with bioinactive and immunoreactive GH have also been reported. We describe here a new bioassay system for GH determination using the BaF/GM cell line, which proliferates in a dose-dependent manner on hGH addition; cell proliferation was blocked by anti-hGH antibody. This bioassay had the lowest detection limit (∼0.02 ng/ml) reported thus far and the highest specificity for GH. The bioassay results were compared with those of an immunoradiometric assay across 163 patient samples in various endocrine states. A close correlation (the ratio of bioactivity/immunoreactivity was 1.04 ± 0.33, mean ± SD) was observed between bioactivity and immunoreactivity in these samples. The newly developed system is a specific, sensitive, easy, and fast bioassay system for GH determination; we consider it useful for evaluating GH bioactivity in various endocrine states. © 2012 Wiley Periodicals, Inc.

  7. Seasonal stomatal behavior of a common desert shrub and the influence of plant neighbors.

    Science.gov (United States)

    Kropp, Heather; Ogle, Kiona

    2015-02-01

    Stomata simultaneously regulate plant carbon gain and water loss, and patterns of stomatal conductance (g(s)) provide insight into water use strategies. In arid systems, g(s) varies seasonally based on factors such as water availability and temperature. Moreover, the presence and species identity of neighboring plants likely affects g(s) of the focal plant by altering available soil water and microclimate conditions. We investigated stomatal behavior in Larrea tridentata, a drought-tolerant, evergreen shrub occurring throughout the arid southwestern United States. We measured g(s) in Larrea over multiple seasons in the presence of neighbors representing different woody species. The data were analyzed in the context of a commonly used phenomenological model that relates g(s) to vapor pressure deficit (D) to understand spatial and temporal differences in stomatal behavior. We found that g(s) in Larrea was affected by neighborhood association, and these effects varied seasonally. The greatest effect of neighborhood association on g(s) occurred during the winter period, where Larrea growing alone (without neighbors) had higher g(s) compared to Larrea growing with neighbors. Larrea's stomatal sensitivity to D and reference conductance (i.e., g(s) at D = 1 kPa) also differed significantly among different neighbor associations. Random effects indicated reference g(s) varied over short time scales (daily), while stomatal sensitivity showed little daily or seasonal variation, but was notably affected by neighbor associations such that neighboring species, especially trees, reduced Larrea's sensitivity to D. Overall, seasonal dynamics and neighborhood conditions appear critical to understanding temporal and spatial variation in Larrea's physiological behavior.

  8. Identification of Burkholderia pseudomallei Near-Neighbor Species in the Northern Territory of Australia.

    Directory of Open Access Journals (Sweden)

    Jennifer L Ginther

    Full Text Available Identification and characterization of near-neighbor species are critical to the development of robust molecular diagnostic tools for biothreat agents. One such agent, Burkholderia pseudomallei, a soil bacterium and the causative agent of melioidosis, is lacking in this area because of its genomic diversity and widespread geographic distribution. The Burkholderia genus contains over 60 species and occupies a large range of environments including soil, plants, rhizospheres, water, animals and humans. The identification of novel species in new locations necessitates the need to identify the true global distribution of Burkholderia species, especially the members that are closely related to B. pseudomallei. In our current study, we used the Burkholderia-specific recA sequencing assay to analyze environmental samples from the Darwin region in the Northern Territory of Australia where melioidosis is endemic. Burkholderia recA PCR negative samples were further characterized using 16s rRNA sequencing for species identification. Phylogenetic analysis demonstrated that over 70% of the bacterial isolates were identified as B. ubonensis indicating that this species is common in the soil where B. pseudomallei is endemic. Bayesian phylogenetic analysis reveals many novel branches within the B. cepacia complex, one novel B. oklahomensis-like species, and one novel branch containing one isolate that is distinct from all other samples on the phylogenetic tree. During the analysis with recA sequencing, we discovered 2 single nucleotide polymorphisms in the reverse priming region of B. oklahomensis. A degenerate primer was developed and is proposed for future use. We conclude that the recA sequencing technique is an effective tool to classify Burkholderia and identify soil organisms in a melioidosis endemic area.

  9. WE-E-BRE-03: Biological Validation of a Novel High-Throughput Irradiator for Predictive Radiation Sensitivity Bioassays

    International Nuclear Information System (INIS)

    Fowler, TL; Martin, JA; Shepard, AJ; Bailey, AM; Nickel, KP; Kimple, RJ; Bednarz, BP

    2014-01-01

    Purpose: The large dose-response variation in both tumor and normal cells between individual patients has led to the recent implementation of predictive bioassays of patient-specific radiation sensitivity in order to personalize radiation therapy. This exciting new clinical paradigm has led us to develop a novel high-throughput, variable dose-rate irradiator to accompany these efforts. Here we present the biological validation of this irradiator through the use of human cells as a relative dosimeter assessed by two metrics, DNA double-strand break repair pathway modulation and intercellular reactive oxygen species production. Methods: Immortalized human tonsilar epithelial cells were cultured in 96-well micro titer plates and irradiated in groups of eight wells to absorbed doses of 0, 0.5, 1, 2, 4, and 8 Gy. High-throughput immunofluorescent microscopy was used to detect γH2AX, a DNA double-strand break repair mechanism recruiter. The same analysis was performed with the cells stained with CM-H2DCFDA that produces a fluorescent adduct when exposed to reactive oxygen species during the irradiation cycle. Results: Irradiations of the immortalized human tonsilar epithelial cells at absorbed doses of 0, 0.5, 1, 2, 4, and 8 Gy produced excellent linearity in γH2AX and CM-H2DCFDA with R2 values of 0.9939 and 0.9595 respectively. Single cell gel electrophoresis experimentation for the detection of physical DNA double-strand breaks in ongoing. Conclusions: This work indicates significant potential for our high-throughput variable dose rate irradiator for patient-specific predictive radiation sensitivity bioassays. This irradiator provides a powerful tool by increasing the efficiency and number of assay techniques available to help personalize radiation therapy

  10. Grain price spikes and beggar-thy-neighbor policy responses

    DEFF Research Database (Denmark)

    Jensen, Hans Grinsted; Anderson, Kym

    2017-01-01

    When prices spike in international grain markets, national governments often reduce the extent to which that spike affects their domestic food markets. Those actions exacerbate the price spike and international welfare transfer associated with that terms of trade change. Several recent analyses...... have assessed the extent to which those policies contributed to the 2006–08 international price rises but only by focusing on one commodity or by using a back-of-the envelope (BOTE) method. The present more comprehensive analysis uses a global, economy-wide model that is able to take account...... of the interactions between markets for farm products that are closely related in production and/or consumption and able to estimate the impacts of those insulating policies on grain prices and on the grain trade and economic welfare of the world's various countries. Our results support the conclusion from earlier...

  11. Grain price spikes and beggar-thy-neighbor policy responses

    DEFF Research Database (Denmark)

    Jensen, Hans Grinsted; Anderson, Kym

    When prices spike in international grain markets, national governments often reduce the extent to which that spike affects their domestic food markets. Those actions exacerbate the price spike and international welfare transfer associated with that terms of trade change. Several recent analyses...... have assessed the extent to which those policies contributed to the 2006-08 international price rise, but only by focusing on one commodity or using a back-of-the envelope (BOTE) method. This paper provides a more-comprehensive analysis using a global economy-wide model that is able to take account...... of the interactions between markets for farm products that are closely related in production and/or consumption, and able to estimate the impacts of those insulating policies on grain prices and on the grain trade and economic welfare of the world’s various countries. Our results support the conclusion from earlier...

  12. Fundamental and Harmonic Oscillations in Neighboring Coronal Loops

    Science.gov (United States)

    Li, Hongbo; Liu, Yu; Vai Tam, Kuan

    2017-06-01

    We present observations of multimode (fundamental and harmonic) oscillations in a loop system, which appear to be simultaneously excited by a GOES C-class flare. Analysis of the periodic oscillations reveals that (1) the primary loop with a period of P a ≈ 4 minutes and a secondary loop with two periods of P a ≈ 4 minutes and P b ≈ 2 minutes are detected simultaneously in closely spaced loop strands; (2) both oscillation components have their peak amplitudes near the loop apex, while in the second loop the low-frequency component P a dominates in a loop segment that is two times larger than the high-frequency component P b ; (3) the harmonic mode P b shows the largest deviation from a sinusoidal loop shape at the loop apex. We conclude that multiple harmonic modes with different displacement profiles can be excited simultaneously even in closely spaced strands, similar to the overtones of a violin string.

  13. Comparative balance of border regulations in four neighboring Caribbean countries

    Directory of Open Access Journals (Sweden)

    Silvia Cristina Mantilla Valbuena

    2016-07-01

    Full Text Available This article seeks to investigate whether there is a potential for border integration among four adjoining Caribbean countries: Colombia, Nicaragua, Panama and Costa Rica. The discussion is part of the “cross-border” concept and the integration of subnational entities in two or more nation states, with particular emphasis on the role played by the societies that inhabit border regions. A comparative analysis model is used to assess border regulations in each country’s various territorial levels based on relevant legal elements, autonomous processes and decentralization. The article concludes that the more modern each country’s border regulations and constitutional, political and administrative reforms are, the greater the likelihood of cross-border integration. Colombia and Nicaragua have the highest potential for integrating their borders, whereas Panama and Costa Rica have the lowest potential.

  14. Research synergy and drug development: Bright stars in neighboring constellations.

    Science.gov (United States)

    Keserci, Samet; Livingston, Eric; Wan, Lingtian; Pico, Alexander R; Chacko, George

    2017-11-01

    Drug discovery and subsequent availability of a new breakthrough therapeutic or 'cure' is a compelling example of societal benefit from research advances. These advances are invariably collaborative, involving the contributions of many scientists to a discovery network in which theory and experiment are built upon. To document and understand such scientific advances, data mining of public and commercial data sources coupled with network analysis can be used as a digital methodology to assemble and analyze component events in the history of a therapeutic. This methodology is extensible beyond the history of therapeutics and its use more generally supports (i) efficiency in exploring the scientific history of a research advance (ii) documenting and understanding collaboration (iii) portfolio analysis, planning and optimization (iv) communication of the societal value of research. Building upon prior art, we have conducted a case study of five anti-cancer therapeutics to identify the collaborations that resulted in the successful development of these therapeutics both within and across their respective networks. We have linked the work of over 235,000 authors in roughly 106,000 scientific publications that capture the research crucial for the development of these five therapeutics. Applying retrospective citation discovery, we have identified a core set of publications cited in the networks of all five therapeutics and additional intersections in combinations of networks. We have enriched the content of these networks by annotating them with information on research awards from the US National Institutes of Health (NIH). Lastly, we have mapped these awards to their cognate peer review panels, identifying another layer of collaborative scientific activity that influenced the research represented in these networks.

  15. Research synergy and drug development: Bright stars in neighboring constellations

    Directory of Open Access Journals (Sweden)

    Samet Keserci

    2017-11-01

    Full Text Available Drug discovery and subsequent availability of a new breakthrough therapeutic or ‘cure’ is a compelling example of societal benefit from research advances. These advances are invariably collaborative, involving the contributions of many scientists to a discovery network in which theory and experiment are built upon. To document and understand such scientific advances, data mining of public and commercial data sources coupled with network analysis can be used as a digital methodology to assemble and analyze component events in the history of a therapeutic. This methodology is extensible beyond the history of therapeutics and its use more generally supports (i efficiency in exploring the scientific history of a research advance (ii documenting and understanding collaboration (iii portfolio analysis, planning and optimization (iv communication of the societal value of research. Building upon prior art, we have conducted a case study of five anti-cancer therapeutics to identify the collaborations that resulted in the successful development of these therapeutics both within and across their respective networks. We have linked the work of over 235,000 authors in roughly 106,000 scientific publications that capture the research crucial for the development of these five therapeutics. Applying retrospective citation discovery, we have identified a core set of publications cited in the networks of all five therapeutics and additional intersections in combinations of networks. We have enriched the content of these networks by annotating them with information on research awards from the US National Institutes of Health (NIH. Lastly, we have mapped these awards to their cognate peer review panels, identifying another layer of collaborative scientific activity that influenced the research represented in these networks. Keywords: Information science, Cancer research

  16. Relevance of TSH-receptor antibody levels in predicting disease course in Graves' orbitopathy: comparison of the third-generation TBII assay and Mc4-TSI bioassay.

    Science.gov (United States)

    Jang, S Y; Shin, D Y; Lee, E J; Lee, S Y; Yoon, J S

    2013-08-01

    To investigate if TSH-receptor antibody (TRAb) levels measured in early Graves' orbitopathy (GO) stages are predictive of clinical disease course beyond 1 year after initial GO diagnosis and to compare performance of two newly developed TRAb assays (third-generation thyrotropin-binding inhibitor immunoglobulin (TBII) assay vs Mc4-thyroid-stimulating immunoglobulin (TSI) bioassay) in predicting disease course. Newly diagnosed, untreated GO patients whose duration of ocular symptoms was less than 6 months were included. One year after initial diagnosis, all patients were classified as presenting either a mild (Group 1) or severe course (Group 2) according to their clinical manifestations. The measurements of two TRAb assays at initial GO diagnosis were used for analysis. Data from 112 patients were available for analysis. Seventy-three patients (65.2%) were designated as Group 1, and 39 patients (34.8%) as Group 2. Patients with higher initial TRAb levels demonstrated a higher risk of severe disease course upon multiple regression analysis (PTSI assays were 10.67 IU/l and 555.10%, respectively, with assay specificities of 84.9 and 89.0%. The TBII assay predictive power (area under the curve (AUC)=0.817; 95% confidence interval (CI) =0.732-0.902) was equivalent to the TSI bioassay (AUC=0.868, 95% CI=0.803-0.934) (P=0.203). The predictive power of the third-generation TBII assay and Mc4-TSI bioassay are similarly strong. Measurement of TRAb using either third-generation TBII or Mc4-TSI in early GO periods would provide important prognostic information on future GO course.

  17. Responses of lone star tick (acari: ixodidae) nymphs to the repellent deet applied in acetone and ethanol solutions in vitro bioassays

    Science.gov (United States)

    Behavioral bioassays remain a standard tool in the discovery, development, and registration of repellents. Although tick repellent bioassays tend to be rather uncomplicated, several factors can influence their outcomes. Typically repellent bioassays use a solvent, such as acetone or ethanol, to disp...

  18. Identification of Lilial as a fragrance sensitizer in a perfume by bioassay-guided chemical fractionation and structure-activity relationships

    DEFF Research Database (Denmark)

    Gimenéz-Arnau, Elena; Andersen, K E; Bruze, M

    2000-01-01

    Fragrance materials are among the most common causes of allergic contact dermatitis. The aim of this study was to identify in a perfume fragrance allergens not included in the fragrance mix, by use of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships...... (SARs). The basis for the investigation was a 45-year-old woman allergic to her own perfume. She had a negative patch test to the fragrance mix and agreed to participate in the study. Chemical fractionation of the perfume concentrate was used for repeated patch testing and/or repeated open application...

  19. Proxy-Based IPv6 Neighbor Discovery Scheme for Wireless LAN Based Mesh Networks

    Science.gov (United States)

    Lee, Jihoon; Jeon, Seungwoo; Kim, Jaehoon

    Multi-hop Wireless LAN-based mesh network (WMN) provides high capacity and self-configuring capabilities. Due to data forwarding and path selection based on MAC address, WMN requires additional operations to achieve global connectivity using IPv6 address. The neighbor discovery operation over WLAN mesh networks requires repeated all-node broadcasting and this gives rise to a big burden in the entire mesh networks. In this letter, we propose the proxy neighbor discovery scheme for optimized IPv6 communication over WMN to reduce network overhead and communication latency. Using simulation experiments, we show that the control overhead and communication setup latency can be significantly reduced using the proxy-based neighbor discovery mechanism.

  20. Electronic transport of molecular nanowires by considering of electron hopping energy between the second neighbors

    Directory of Open Access Journals (Sweden)

    H Rabani

    2015-07-01

    Full Text Available In this paper, we study the electronic conductance of molecular nanowires by considering the electron hopping between the first and second neighbors with the help Green’s function method at the tight-binding approach. We investigate three types of structures including linear uniform and periodic chains as well as poly(p-phenylene molecule which are embedded between two semi-infinite metallic leads. The results show that in the second neighbor approximation, the resonance, anti-resonance and Fano phenomena occur in the conductance spectra of these structures. Moreover, a new gap is observed at edge of the lead energy band wich its width depends on the value of the electron hopping energy between the second neighbors. In the systems including intrinsic gap, this hopping energy shifts the gap in the energy spectra.

  1. Medical Information Retrieval Enhanced with User's Query Expanded with Tag-Neighbors

    DEFF Research Database (Denmark)

    Durao, Frederico; Bayyapu, Karunakar Reddy; Xu, Guandong

    2013-01-01

    Under-specified queries often lead to undesirable search results that do not contain the information needed. This problem gets worse when it comes to medical information, a natural human demand everywhere. Existing search engines on the Web often are unable to handle medical search well because...... they do not consider its special requirements. Often a medical information searcher is uncertain about his exact questions and unfamiliar with medical terminology. To overcome the limitations of under-specified queries, we utilize tags to enhance information retrieval capabilities by expanding users......’ original queries with context-relevant information. We compute a set of significant tag neighbor candidates based on the neighbor frequency and weight, and utilize the qualified tag neighbors to expand an entry query. The proposed approach is evaluated by using MedWorm medical article collection...

  2. A multilevel-skin neighbor list algorithm for molecular dynamics simulation

    Science.gov (United States)

    Zhang, Chenglong; Zhao, Mingcan; Hou, Chaofeng; Ge, Wei

    2018-01-01

    Searching of the interaction pairs and organization of the interaction processes are important steps in molecular dynamics (MD) algorithms and are critical to the overall efficiency of the simulation. Neighbor lists are widely used for these steps, where thicker skin can reduce the frequency of list updating but is discounted by more computation in distance check for the particle pairs. In this paper, we propose a new neighbor-list-based algorithm with a precisely designed multilevel skin which can reduce unnecessary computation on inter-particle distances. The performance advantages over traditional methods are then analyzed against the main simulation parameters on Intel CPUs and MICs (many integrated cores), and are clearly demonstrated. The algorithm can be generalized for various discrete simulations using neighbor lists.

  3. What Will the Neighbors Think? Building Large-Scale Science Projects Around the World

    International Nuclear Information System (INIS)

    Jones, Craig; Mrotzek, Christian; Toge, Nobu; Sarno, Doug

    2007-01-01

    Public participation is an essential ingredient for turning the International Linear Collider into a reality. Wherever the proposed particle accelerator is sited in the world, its neighbors -- in any country -- will have something to say about hosting a 35-kilometer-long collider in their backyards. When it comes to building large-scale physics projects, almost every laboratory has a story to tell. Three case studies from Japan, Germany and the US will be presented to examine how community relations are handled in different parts of the world. How do particle physics laboratories interact with their local communities? How do neighbors react to building large-scale projects in each region? How can the lessons learned from past experiences help in building the next big project? These and other questions will be discussed to engage the audience in an active dialogue about how a large-scale project like the ILC can be a good neighbor.

  4. A Novel Preferential Diffusion Recommendation Algorithm Based on User’s Nearest Neighbors

    Directory of Open Access Journals (Sweden)

    Fuguo Zhang

    2017-01-01

    Full Text Available Recommender system is a very efficient way to deal with the problem of information overload for online users. In recent years, network based recommendation algorithms have demonstrated much better performance than the standard collaborative filtering methods. However, most of network based algorithms do not give a high enough weight to the influence of the target user’s nearest neighbors in the resource diffusion process, while a user or an object with high degree will obtain larger influence in the standard mass diffusion algorithm. In this paper, we propose a novel preferential diffusion recommendation algorithm considering the significance of the target user’s nearest neighbors and evaluate it in the three real-world data sets: MovieLens 100k, MovieLens 1M, and Epinions. Experiments results demonstrate that the novel preferential diffusion recommendation algorithm based on user’s nearest neighbors can significantly improve the recommendation accuracy and diversity.

  5. Learn good from bad: Effects of good and bad neighbors in spatial prisoners' dilemma games

    Science.gov (United States)

    Lu, Peng

    2015-10-01

    Cooperation is vital for the human society and this study focuses on how to promote cooperation. In our stratification model, there exist three classes: two minorities are elites who are prone to cooperate and scoundrels who are born to defect; one majority is the class of common people. Agents of these three classes interact with each other on a square lattice. Commons' cooperation and its factors are investigated. Contradicting our common sense, it indicates that elites play a negative role while scoundrels play a positive one in promoting commons' cooperation. Besides, effects of good and bad neighbors vary with temptation. When the temptation is smaller the positive effect is able to overcome the negative effect, but the later prevails when the temptation is larger. It concludes that common people are more prone to cooperate in harsh environment with bad neighbors, and a better environment with good neighbors merely leads to laziness and free riding of commons.

  6. Bioassay of the Nucleopolyhedrosis Virus of Neodiprion sertifer (Hymenoptera: Diprionidae)

    Science.gov (United States)

    M.A. Mohamed; J.D. Podgwaite

    1982-01-01

    Linear regression analysis of probit mortality versus several concentrations of nucleopolyhedrosis virus of Neodiprion sertifer resulted in the equation Y = 2.170 + 0.872X. An LC50 was calculated at 1758 PIB/ml. Also, the incubation time of the virus was dependent on its concentration. Most insect viruses possess the potential...

  7. Changes in chemical composition and bioassay assessment of ...

    African Journals Online (AJOL)

    Dr. J. T. Ekanem

    2005-03-20

    Mar 20, 2005 ... open manually to obtain the wastes (exocarp). The waste was pounded to a fine meal using mortar and pestle. A sample of the raw meal was taken for analysis. Three kilograms of the meal was subjected to lactic fermentation following the procedures described by Annongu et al.5. The 3kg of the fermented ...

  8. Scenario-targeted toxicity assessment through multiple endpoint bioassays in a soil posing unacceptable environmental risk according to regulatory screening values.

    Science.gov (United States)

    Rodriguez-Ruiz, A; Etxebarria, J; Boatti, L; Marigómez, I

    2015-09-01

    Lanestosa is a chronically polluted site (derelict mine) where the soil (Lanestosa (LA) soil) exceeds screening values (SVs) of regulatory policies in force (Basque Country; Europe) for Zn, Pb and Cd. A scenario-targeted toxicity assessment was carried out on the basis of a multi-endpoint bioassay approach. Acute and chronic toxicity bioassays were conducted with selected test species (Vibrio fischeri, Dictyostelium discoideum, Lactuca sativa, Raphanus sativus and Eisenia fetida) in combination with chemical analysis of soils and elutriates and with bioaccumulation studies in earthworms. Besides, the toxicity profile was compared with that of the mine runoff (RO) soil and of a fresh artificially polluted soil (LAAPS) resembling LA soil pollutant profile. Extractability studies in LA soil revealed that Pb, Zn and Cd were highly available for exchange and/or release into the environment. Indeed, Pb and Zn were accumulated in earthworms and LA soil resulted to be toxic. Soil respiration, V. fischeri, vegetative and developmental cycles of D. discoideum and survival and juvenile production of E. fetida were severely affected. These results confirmed that LA soil had unacceptable environmental risk and demanded intervention. In contrast, although Pb and Zn concentrations in RO soil revealed also unacceptable risk, both metal extractability and toxicity were much lower than in LA soil. Thus, within the polluted site, the need for intervention varied between areas that posed dissimilar risk. Besides, since LAAPS, with a high exchangeable metal fraction, was the most toxic, ageing under in situ natural conditions seemingly contributed to attenuate LA soil risk. As a whole, combining multi-endpoint bioassays with scenario-targeted analysis (including leaching and ageing) provides reliable risk assessment in soils posing unacceptable environmental risk according to SVs, which is useful to optimise the required intervention measures.

  9. NC Machine Tools Fault Diagnosis Based on Kernel PCA and k-Nearest Neighbor Using Vibration Signals

    Directory of Open Access Journals (Sweden)

    Zhou Yuqing

    2015-01-01

    Full Text Available This paper focuses on the fault diagnosis for NC machine tools and puts forward a fault diagnosis method based on kernel principal component analysis (KPCA and k-nearest neighbor (kNN. A data-dependent KPCA based on covariance matrix of sample data is designed to overcome the subjectivity in parameter selection of kernel function and is used to transform original high-dimensional data into low-dimensional manifold feature space with the intrinsic dimensionality. The kNN method is modified to adapt the fault diagnosis of tools that can determine thresholds of multifault classes and is applied to detect potential faults. An experimental analysis in NC milling machine tools is developed; the testing result shows that the proposed method is outperforming compared to the other two methods in tool fault diagnosis.

  10. Self-Organizing Map with False-Neighbor Degree between Neurons for Effective Self-Organization

    Science.gov (United States)

    Matsushita, Haruna; Nishio, Yoshifumi

    In the real world, it is not always true that neighboring houses are physically adjacent or close to each other. in other words, “neighbors” are not always “true neighbors” In this study, we propose a new Self-Organizing Map (SOM) algorithm, SOM with False-Neighbor degree between neurons (called FN-SOM). The behavior of FN-SOM is investigated with learning for various input data. We confirm that FN-SOM can obtain a more effective map reflecting the distribution state of input data than the conventional SOM and Growing Grid.

  11. Stuttering attitudes among Turkish family generations and neighbors from representative samples.

    Science.gov (United States)

    Ozdemir, R Sertan; St Louis, Kenneth O; Topbaş, Seyhun

    2011-12-01

    Attitudes toward stuttering, measured by the Public Opinion Survey of Human Attributes-Stuttering (POSHA-S), are compared among (a) two different representative samples; (b) family generations (children, parents, and either grandparents or uncles and aunts) and neighbors; (c) children, parents, grandparents/adult relatives, and neighbors of the same family/neighbor units vs. individuals from different family/neighbor units; and (d) attitudes from one Turkish city with an international database archive. Following a school-based, three-stage, cluster probability sampling scheme, two sets of children, parents, grandparents/adult relatives, and neighbors (50 each) in Eskişehir, Turkey (PROB1 and PROB2) completed Turkish translations of the POSHA-S. The POSHA-S measures attitudes toward stuttering within the context of other attributes, such as obesity and mental illness. Both replicates of the sampling procedure yielded strikingly similar attitudes for stuttering between children, parents, grandparents/adult relatives, and neighbors in PROB1 vs. PROB2, and between all pair-wise comparisons within PROB1 and PROB2. By contrast, attitudes toward obesity and mental illness were dissimilar. Correlations were small to moderate among attitudes of the same family/neighbor units but were essentially nonexistent between different family/neighbor units. Attitudes toward stuttering in Eskişehir were estimated to be less positive than attitudes from a wide range of samples around the world, although exceptions occurred. A school-based probability sampling procedure yielded consistent findings that are likely different from results from convenience samples. Families appear to be an important influence in determining public attitudes toward stuttering and other human attributes. The reader will be able to: (i) identify similarities and differences among attitudes toward stuttering across generations; (ii) identify similarities and differences among attitudes toward stuttering in

  12. Predicting the Maximum Earthquake Magnitude from Seismic Data in Israel and Its Neighboring Countries.

    Science.gov (United States)

    Last, Mark; Rabinowitz, Nitzan; Leonard, Gideon

    2016-01-01

    This paper explores several data mining and time series analysis methods for predicting the magnitude of the largest seismic event in the next year based on the previously recorded seismic events in the same region. The methods are evaluated on a catalog of 9,042 earthquake events, which took place between 01/01/1983 and 31/12/2010 in the area of Israel and its neighboring countries. The data was obtained from the Geophysical Institute of Israel. Each earthquake record in the catalog is associated with one of 33 seismic regions. The data was cleaned by removing foreshocks and aftershocks. In our study, we have focused on ten most active regions, which account for more than 80% of the total number of earthquakes in the area. The goal is to predict whether the maximum earthquake magnitude in the following year will exceed the median of maximum yearly magnitudes in the same region. Since the analyzed catalog includes only 28 years of complete data, the last five annual records of each region (referring to the years 2006-2010) are kept for testing while using the previous annual records for training. The predictive features are based on the Gutenberg-Richter Ratio as well as on some new seismic indicators based on the moving averages of the number of earthquakes in each area. The new predictive features prove to be much more useful than the indicators traditionally used in the earthquake prediction literature. The most accurate result (AUC = 0.698) is reached by the Multi-Objective Info-Fuzzy Network (M-IFN) algorithm, which takes into account the association between two target variables: the number of earthquakes and the maximum earthquake magnitude during the same year.

  13. Evaluation of the suitability of free-energy minimization using nearest-neighbor energy parameters for RNA secondary structure prediction

    Directory of Open Access Journals (Sweden)

    Cobaugh Christian W

    2004-08-01

    Full Text Available Abstract Background A detailed understanding of an RNA's correct secondary and tertiary structure is crucial to understanding its function and mechanism in the cell. Free energy minimization with energy parameters based on the nearest-neighbor model and comparative analysis are the primary methods for predicting an RNA's secondary structure from its sequence. Version 3.1 of Mfold has been available since 1999. This version contains an expanded sequence dependence of energy parameters and the ability to incorporate coaxial stacking into free energy calculations. We test Mfold 3.1 by performing the largest and most phylogenetically diverse comparison of rRNA and tRNA structures predicted by comparative analysis and Mfold, and we use the results of our tests on 16S and 23S rRNA sequences to assess the improvement between Mfold 2.3 and Mfold 3.1. Results The average prediction accuracy for a 16S or 23S rRNA sequence with Mfold 3.1 is 41%, while the prediction accuracies for the majority of 16S and 23S rRNA structures tested are between 20% and 60%, with some having less than 20% prediction accuracy. The average prediction accuracy was 71% for 5S rRNA and 69% for tRNA. The majority of the 5S rRNA and tRNA sequences have prediction accuracies greater than 60%. The prediction accuracy of 16S rRNA base-pairs decreases exponentially as the number of nucleotides intervening between the 5' and 3' halves of the base-pair increases. Conclusion Our analysis indicates that the current set of nearest-neighbor energy parameters in conjunction with the Mfold folding algorithm are unable to consistently and reliably predict an RNA's correct secondary structure. For 16S or 23S rRNA structure prediction, Mfold 3.1 offers little improvement over Mfold 2.3. However, the nearest-neighbor energy parameters do work well for shorter RNA sequences such as tRNA or 5S rRNA, or for larger rRNAs when the contact distance between the base-pairs is less than 100 nucleotides.

  14. Genotoxicity of SPL (spent pot lining) as measured by Tradescantia bioassays.

    Science.gov (United States)

    Andrade-Vieira, L F; Davide, L C; Gedraite, L S; Campos, J M S; Azevedo, H

    2011-10-01

    Spent Pot Liner (SPL) is a solid waste product generated in the process of aluminum production. Tradescantia micronuclei (Trad-MN) and stamen hair mutation (Trad-SHM) bioassays are very useful tests to assess genotoxicity of environmental pollutants. In the present study, we intended to investigate the genotoxicity of this waste with Tradescantia bioassays using leachates of SPL simulating the natural leachability of SPL in soil. The formation of micronuclei (MN) was found to be concentration dependent. MN frequency enhanced significantly with SPL treatment. In addition, SPL also appeared to increase the percentage of dyads and triads. Trad-SHM assay showed that SPL increases pink mutation events as SPL concentration increases. These results demonstrated that SPL is a cytogenotoxic agent that affects different genetic end-points (induction of micronuclei and point mutations) even at low concentration (2% and 3%). Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Multi-scale magnetic nanoparticle based optomagnetic bioassay for sensitive DNA and bacteria detection

    DEFF Research Database (Denmark)

    Tian, Bo; Zardán Gómez De La Torre, Teresa; Donolato, Marco

    2016-01-01

    Benefiting from their rapid readout, highly flexible devices and low-cost portable systems, optomagnetic biosensors have drawn increased attention in recent years as bioassay technologies for small molecules, biomarkers, DNA, and bacteria. Herein, an optomagnetic bioassay strategy suitable...... for point-of-care diagnostics, utilizing functionalized magnetic nanoparticles (100 nm) with Brownian relaxation behavior is optimized in order to obtain higher detection sensitivity for DNA molecules and bacteria. Presence of target DNA sequences or bacteria changes the dynamic behavior of the magnetic...... nanoparticles (binding to the target) and thus the optomagnetic response of the sample, which is measured by an optomagnetic setup including a 405 nm laser and a photodetector. The limit of detection is mainly set by the lowest measurable concentration of magnetic nanoparticles. Herein, as new results compared...

  16. SERMs and SARMs: detection of their activities with yeast based bioassays.

    Science.gov (United States)

    Bovee, Toine F H; Thevis, Mario; Hamers, Astrid R M; Peijnenburg, Ad A C M; Nielen, Michel W F; Schoonen, Willem G E J

    2010-01-01

    Selective estrogen receptor modulators (SERMs) and selective androgen receptor modulators (SARMs) are compounds that activate their cognate receptor in particular target tissues without affecting other organs. Many of these compounds will find their use in therapeutic treatments. However, they also will have a high potential for misuse in veterinary practice and the sporting world. Here we demonstrate that yeast estrogen and androgen bioassays can be used to detect SERMs and SARMs, and are also useful screening tools to investigate their mode of action. Six steroidal 11beta-substituents of E2 (SERMs) and some arylpropionamide- and quinoline-based SARMs were tested. In addition, 7 compounds previously tested on AR agonism and determined as inactive in the yeast androgen bioassay, while QSAR modelling revealed strong binding to the human androgen receptor, are now shown to act as AR antagonists. Copyright 2009 Elsevier Ltd. All rights reserved.

  17. On-chip genotoxic bioassay based on bioluminescence reporter system using three-dimensional microfluidic network

    OpenAIRE

    Maehana, Koji; Tani, Hirofumi; Kamidate, Tamio

    2006-01-01

    Microchip-based genotoxic bioassay using sensing Escherichia coli strains has been performed. In this method, the assay was conducted in three-dimensional microfluidic network constructed by a silicon perforated microwell array chip and two poly(dimethylsiloxane) (PDMS) multi-microchannel chips. The sensing strains having firefly luciferase reporter gene under transcriptional control of umuD as an SOS promoter were put into the channels on one of the PDMS chips and immobilized in the silicon ...

  18. Mouse bioassay to assess oestrogenic and anti-oestrogenic compounds: Hydroxytamoxifen, Diethylstilbestrol and Genistein

    Czech Academy of Sciences Publication Activity Database

    Köhlerová, Eva; Škarda, Josef

    2004-01-01

    Roč. 51, č. 5 (2004), s. 209-217 ISSN 0931-184X R&D Projects: GA ČR GA524/02/0406; GA AV ČR IBS5045302; GA AV ČR KSK5020115 Institutional research plan: CEZ:AV0Z5045916 Keywords : bioassay * anti-oestrogens * oestrogenicity Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 0.471, year: 2004

  19. Bioassay using the water soluble fraction of a Nigerian Light Crude ...

    African Journals Online (AJOL)

    Summary: A 96-hour bioassay was conducted using the water soluble fraction of a Nigerian light crude oil sample on Clarias gariepinus fingerlings. 0, 2.5, 5.0, 7.5 and 10 mls of water soluble fractions (WSF) of the oil were added to 1000 litres of de-chlorinated tap water to form 0, 25, 50 , 75 and 100 parts per million ...

  20. Effects of Wind Speed on Aerosol Spray Penetration in Adult Mosquito Bioassay Cages

    Science.gov (United States)

    2008-01-01

    powers a direct-drive air compressor that pro- duces the air blast that creates the pesticide droplet spectrum at the dual venture style, stainless steel...each replication, the straws were carefully placed in individually labeled plastic bags and stored out of the light to prevent any photodegradation ...M, Coughlin J. 2006. The effect of pesticide residue on caged mosquito bioassays. J Am Mosq Control Assoc 22:469–472. Boobar LR, Dobson SE, Perich MJ

  1. Estimation of uranium in bioassay samples of occupational workers by laser fluorimetry

    International Nuclear Information System (INIS)

    Suja, A.; Prabhu, S.P.; Sawant, P.D.; Sarkar, P.K.; Tiwari, A.K.; Sharma, R.

    2010-01-01

    A newly established uranium processing facility has been commissioned at BARC, Trombay. Monitoring of occupational workers at regulars intervals is essential to assess intake of uranium by the workers in this facility. The design and engineering safety features of the plant are such that there is very low probability of uranium getting air borne during normal operations. However, the leakages from the system during routine maintenance of the plant may result in intake of uranium by workers. As per the new biokinetic model for uranium, 63% of uranium entering the blood stream gets directly excreted in urine. Therefore, bioassay monitoring (urinalysis) was recommended for these workers. A group of 21 workers was selected for bioassay monitoring to assess the existing urinary excretion levels of uranium before the commencement of actual work. For this purpose, sample collection kit along with an instruction slip was provided to the workers. Bioassay samples received were wet ashed with conc. nitric acid and hydrogen peroxide to break down the metabolized complexes of uranium and it was co-precipitated with calcium phosphate. Separation of uranium from the matrix was done using ion exchange technique and final activity quantification in these samples was done using laser fluorimeter (Quantalase, Model No. NFL/02). Calibration of the laser fluorimeter is done using 10 ppb uranium standard (WHO, France Ref. No. 180000). Verification of the system performance is done by measuring concentration of uranium in the standards (1 ppb to 100 ppb). Standard addition method was followed for estimation of uranium concentration in the samples. Uranyl ions present in the sample get excited by pulsed nitrogen laser at 337.1 nm, and on de-excitation emit fluorescence light (540 nm) intensity which is measured by the PMT. To estimate the uranium in the bioassay samples, a known aliquot of the sample was mixed with 5% sodium pyrophosphate and fluorescence intensity was measured

  2. Bioassay method for toxicity studies of insecticide formulations to Tuta absoluta (meyrick, 1917)

    OpenAIRE

    Galdino, Tarcísio Visintin da Silva; Picanço, Marcelo Coutinho; Morais, Elisangela Gomes Fidelis de; Silva, Nilson Rodrigues; Silva, Geverson Aelton Rezende da; Lopes, Mayara Cristina

    2011-01-01

    Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that repre...

  3. Bioassay method for toxicity studies of insecticide formulations to tuta absoluta (meyrick, 1917).

    OpenAIRE

    GALDINO, T. V. da S.; PICANÇO, M. C.; MORAIS, E. G. F. de; SILVA, N. R.; SILVA, G. A. R da; LOPES, M. C.

    2014-01-01

    Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that repre...

  4. Forest structure of Mediterranean yew (Taxus baccata L. populations and neighbor effects on juvenile yew performance in the NE Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Pere Casals

    2015-12-01

    Full Text Available Aim of study: In the Mediterranean region, yew (Taxus baccata L. usually grows with other tree species in mixed forests. Yew recruitment and juvenile growth may depend on the structure of the forest and the net balance between competition for soil water and nutrients with neighbors and facilitation that these neighbors exert by protecting the plants from direct sun exposure. This study aims, at a regional scale, to analyze the structure of forests containing yew, and, on an individual level, to analyze the effect of the surrounding vegetation structure on the performance of yew juveniles.Area of study: The structural typologies of yew populations were defined based on field inventories conducted in 55 plots distributed in 14 localities in the North-Eastern (NE Iberian Peninsula, covering a wide range of yew distribution in the area. In a second step, an analysis of neighboring species' effects on juveniles was conducted based on the data from 103 plots centered in yew juveniles in five localities.Main Results: A cluster analysis classified the inventoried stands into four forest structural types: two multi-stratified forests with scattered yew and two yew groves. Multiple regression modeling showed that the δ13C measured in last year's leaves positively relates to the basal area of conifer neighbors, but negatively with the cover of the yew crown by other trees.Research highlights: At a stand-level, the density of recruits and juveniles (625 ± 104 recruits ha-1, 259 ± 55 juveniles ha-1 in mixed forests was found to be higher than that on yew dominant stands (181 ± 88 recruits ha-1 and 57 ± 88 juveniles ha-1. At an individual-level, the water stress (estimated from leaf δ13C of yew juveniles seems alleviated by the crown cover by neighbors while it increases with the basal area of conifers. Yew conservation should focus on selective felling for the reduction of basal area of neighbors surrounding the target tree, but avoid affecting the

  5. Studies of DNA dumbbells VII: evaluation of the next-nearest-neighbor sequence-dependent interactions in duplex DNA.

    Science.gov (United States)

    Owczarzy, R; Vallone, P M; Goldstein, R F; Benight, A S

    1999-01-01

    Melting experiments were conducted on 22 DNA dumbbells as a function of solvent ionic strength from 25-115 mM Na(+). The dumbbell molecules have short duplex regions comprised of 16-20 base pairs linked on both ends by T(4) single-strand loops. Only the 4-8 central base pairs of the dumbbell stems differ for different molecules, and the six base pairs on both sides of the central sequence and adjoining loops on both ends are the same in every molecule. Results of melting analysis on the 22 new DNA dumbbells are combined with our previous results on 17 other DNA dumbbells, with stem lengths containing from 14-18 base pairs, reported in the first article of this series (Doktycz, Goldstein, Paner, Gallo, and Benight, Biopoly 32, 1992, 849-864). The combination of results comprises a database of optical melting parameters for 39 DNA dumbbells in ionic strengths from 25-115 mM Na(+). This database is employed to evaluate the thermodynamics of singlet, doublet, and triplet sequence-dependent interactions in duplex DNA. Analysis of the 25 mM Na(+) data reveals the existence of significant sequence-dependent triplet or next-nearest-neighbor interactions. The enthalpy of these interactions is evaluated for all possible triplets. Some of the triplet enthalpy values are less than the uncertainty in their evaluation, indicating no measurable interaction for that particular sequence. This finding suggests that the thermodynamic stability of duplex DNA depends on solvent ionic strength in a sequence-dependent manner. As a part of the analysis, the nearest-neighbor (base pair doublet) interactions in 55, 85, and 115 mM Na(+) are also reevaluated from the larger database. Copyright 2000 John Wiley & Sons, Inc.

  6. A bioassay method for americium and curium in feces

    International Nuclear Information System (INIS)

    Alexandre Gagne; Dominic Lariviere; Joel Surette; Sheila Kramer-Tremblay; Xiongxin Dai; Candice Didychuk

    2013-01-01

    Fecal radiobioassay is an essential and sensitive tool to estimate the internal intake of actinides after a radiological incident. A new fecal analysis method, based on lithium metaborate fusion of fecal ash for complete sample dissolution followed by sequential column chromatography separation of actinides, has been developed for the determination of low-level Am and Cm in a large size sample. Spiked synthetic fecal samples were analyzed to evaluate method performance against the acceptance criteria for radiobioassay as defined by ANSI N13.30; both satisfactory accuracy and repeatability were achieved. This method is a promising candidate for reliable dose assessment of low level actinide exposure to meet the regulatory requirements of routine radiobioassay for nuclear workers and the public. (author)

  7. Comparison of the sensitivity of seven marine and freshwater bioassays as regards antidepressant toxicity assessment.

    Science.gov (United States)

    Minguez, Laetitia; Di Poi, Carole; Farcy, Emilie; Ballandonne, Céline; Benchouala, Amira; Bojic, Clément; Cossu-Leguille, Carole; Costil, Katherine; Serpentini, Antoine; Lebel, Jean-Marc; Halm-Lemeille, Marie-Pierre

    2014-11-01

    The hazards linked to pharmaceutical residues like antidepressants are currently a major concern of ecotoxicology because they may have adverse effects on non-target aquatic organisms. Our study assesses the ecotoxicity of three antidepressants (fluoxetine, sertraline and clomipramine) using a battery of marine and freshwater species representing different trophic levels, and compares the bioassay sensitivity levels. We selected the following bioassays: the algal growth inhibition test (Skeletonema marinoi and Pseudokirchneriella subcapitata), the microcrustacean immobilization test (Artemia salina and Daphnia magna), development and adult survival tests on Hydra attenuata, embryotoxicity and metamorphosis tests on Crassostrea gigas, and in vitro assays on primary cultures of Haliotis tuberculata hemocytes. The results showed high inter-species variability in EC50-values ranging from 43 to 15,600 µg/L for fluoxetine, from 67 to 4,400 µg/L for sertraline, and from 4.70 µg/L to more than 100,000 µg/L for clomipramine. Algae (S. marinoi and P. subcapitata) and the embryo-larval stages of the oyster C. gigas were the most sensitive taxa. This raises an issue due to their ecological and/or economic importance. The marine crustacean A. salina was the least sensitive species. This difference in sensitivity between bioassays highlights the importance of using a test battery.

  8. Building bio-assays with magnetic particles on a digital microfluidic platform.

    Science.gov (United States)

    Kokalj, Tadej; Pérez-Ruiz, Elena; Lammertyn, Jeroen

    2015-09-25

    Digital microfluidics (DMF) has emerged as a promising liquid handling technology for a variety of applications, demonstrating great potential both in terms of miniaturization and automation. DMF is based on the manipulation of discrete, independently controllable liquid droplets, which makes it highly reconfigurable and reprogrammable. One of its most exclusive advantages, compared to microchannel-based microfluidics, is its ability to precisely handle solid nano- and microsized objects, such as magnetic particles. Magnetic particles have become very popular in the last decade, since their high surface-to-volume ratio and the possibility to magnetically separate them from the matrix make them perfect suitable as a solid support for bio-assay development. The potential of magnetic particles in DMF-based bio-assays has been demonstrated for various applications. In this review we discuss the latest developments of magnetic particle-based DMF bio-assays with the aim to present, identify and analyze the trends in the field. We also discuss the state-of-the art of device integration, current status of commercialization and issues that still need to be addressed. With this paper we intend to stimulate researchers to exploit and unveil the potential of these exciting tools, which will shape the future of modern biochemistry, microbiology and biomedical diagnostics. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. The interpretation of disease phenotypes to identify TSE strains following murine bioassay: characterisation of classical scrapie.

    Science.gov (United States)

    Beck, Katy E; Vickery, Christopher M; Lockey, Richard; Holder, Thomas; Thorne, Leigh; Terry, Linda A; Denyer, Margaret; Webb, Paul; Simmons, Marion M; Spiropoulos, John

    2012-11-01

    Mouse bioassay can be readily employed for strain typing of naturally occurring transmissible spongiform encephalopathy cases. Classical scrapie strains have been characterised historically based on the established methodology of assessing incubation period of disease and the distribution of disease-specific vacuolation across the brain following strain stabilisation in a given mouse line. More recent research has shown that additional methods could be used to characterise strains and thereby expand the definition of strain "phenotype". Here we present the phenotypic characteristics of classical scrapie strains isolated from 24 UK ovine field cases through the wild-type mouse bioassay. PrPSc immunohistochemistry (IHC), paraffin embedded tissue blots (PET-blot) and Western blotting approaches were used to determine the neuroanatomical distribution and molecular profile of PrPSc associated with each strain, in conjunction with traditional methodologies. Results revealed three strains isolated through each mouse line, including a previously unidentified strain. Moreover IHC and PET-blot methodologies were effective in characterising the strain-associated types and neuroanatomical locations of PrPSc. The use of Western blotting as a parameter to define classical scrapie strains was limited. These data provide a comprehensive description of classical scrapie strain phenotypes on isolation through the mouse bioassay that can provide a reference for further scrapie strain identification.

  10. Sampling method, storage and pretreatment of sediment affect AVS concentrations with consequences for bioassay responses

    Energy Technology Data Exchange (ETDEWEB)

    Lange, H.J. de [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands); Centre for Ecosystem Studies, Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen (Netherlands)], E-mail: marieke.delange@wur.nl; Griethuysen, C. van; Koelmans, A.A. [Aquatic Ecology and Water Quality Management Group, Wageningen University, Wageningen University and Research Centre, P.O. Box 8080, 6700 DD, Wageningen (Netherlands)

    2008-01-15

    Sediment treatment and sediment storage may alter sediment toxicity, and consequently biotic response. Purpose of our study was to combine these three aspects (treatment-toxicity-biotic response) in one integrated approach. We used Acid Volatile Sulfide (AVS) concentrations as a proxy of the disturbance of the sediment. AVS and Simultaneously Extracted Metal (SEM) concentrations were compared to bioassay responses with the freshwater benthic macroinvertebrate Asellus aquaticus. Storage conditions and sediment treatment affected AVS but not SEM levels. AVS can be used as a proxy for sediment disturbance. The best way to pretreat the sediment for use in a bioassay in order to maintain initial AVS conditions was to sample the sediment with an Ekman grab, immediately store it in a jar without headspace, and freeze it as soon as possible. In a survey using seven different sediments, bioassay responses of A. aquaticus were correlated with SEM and AVS characteristics. - Change in AVS is a good proxy for sediment disturbance and combined with SEM it can be used as a suitable predictor for biotic effects of sediment contamination.

  11. Experimental and Computational Characterization of Biological Liquid Crystals: A Review of Single-Molecule Bioassays

    Directory of Open Access Journals (Sweden)

    Sungsoo Na

    2009-09-01

    Full Text Available Quantitative understanding of the mechanical behavior of biological liquid crystals such as proteins is essential for gaining insight into their biological functions, since some proteins perform notable mechanical functions. Recently, single-molecule experiments have allowed not only the quantitative characterization of the mechanical behavior of proteins such as protein unfolding mechanics, but also the exploration of the free energy landscape for protein folding. In this work, we have reviewed the current state-of-art in single-molecule bioassays that enable quantitative studies on protein unfolding mechanics and/or various molecular interactions. Specifically, single-molecule pulling experiments based on atomic force microscopy (AFM have been overviewed. In addition, the computational simulations on single-molecule pulling experiments have been reviewed. We have also reviewed the AFM cantilever-based bioassay that provides insight into various molecular interactions. Our review highlights the AFM-based single-molecule bioassay for quantitative characterization of biological liquid crystals such as proteins.

  12. Laboratory bioassays of vegetable oils as kairomonal phagostimulants for grasshoppers (Orthoptera: Acrididae).

    Science.gov (United States)

    Latchininsky, Alexandre V; Schell, Scott P; Lockwood, Jeffrey A

    2007-10-01

    Vegetable oils have kairomonal attractant properties to grasshoppers primarily due to the presence of linoleic and linolenic fatty acids. These fatty acids are dietary essentials for grasshoppers and, once volatilized, can be detected by the insects' olfactory receptors. A laboratory bioassay method has been developed to identify vegetable oils that have fatty acid profiles similar to grasshoppers and that induce grasshopper attraction and feeding. Such oils could be useful kairomonal adjuvants and/or carriers for acridicide formulations. Three sets of laboratory bioassays demonstrated that the addition of a standard aliquot of different vegetable oils resulted in varying degrees of grasshopper feeding on otherwise neutral substrates. Addition of olive oil stimulated the greatest feeding in all three sets of assays, regardless of the age of the tested insects. Furthermore, addition of canola or flax oils markedly enhanced grasshopper feeding. These three oils--i.e., olive, canola, and flax oil--proved to be the best performing grasshopper stimulants. A second group of oils included rapeseed-flax mix and rapeseed oils; however, their performance was not as consistent as oils in the first group--especially with regard to nymphal feeding. A third group of oils consisted of soybean, corn, peanut, and sunflower oil. Theoretical expectations regarding these oils varied wildly, suggesting that the results of a single bioassay should be cautiously interpreted as being negative.

  13. A typical case study involving bioassay measurements at a nuclear power plant

    International Nuclear Information System (INIS)

    Brackett, E.M.; Babineau, G.; Hwang, H.S.; Laurenzo, E.; McCurdy, D.E.

    1986-01-01

    As a principal bioassay testing laboratory for multiple nuclear power facilities, the Yankee Atomic Environmental Laboratory had the opportunity to evaluate the correlation between the temporal variation in in vitro and in vivo measurements and various models presented in ICRP Publications 2 and 30. Two contractors were involved in an incident which resulted in the intake of a number of radionuclides. Initial bioassay measurements, in the form of whole body counts, were conducted immediately after decontamination efforts. At this time it was requested that Yankee staff members take the necessary steps to perform a dose assessment. Extensive measurements, both in vivo and in vitro, were conducted on the individuals for several weeks following the incident. The three most prevalent gamma emitting nuclides (Cr-51, Co-58 and Co-60) found in fecal samples were also the nuclides detected in the highest quantities in the in vivo measurements. Nine gamma emitting nuclides found in Contractor A's fecal sample were not detected by in vivo measurements. The results suggest that the airborne radioactivity intake consisted of primarily nontransportable particles which were swallowed or translocated directly from the lungs to the gastrointestinal system. Results of the bioassay measurements are presented and comparison of the various analyses discussed

  14. Application of bioassays with Enchytraeus crypticus and Folsomia candida to evaluate the toxicity of a metal-contaminated soil, before and after remediation

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Veronica; Simon, Mariano [Univ. de Almeria (Spain). Dept. de Edafologia y Quimica Agricola; Dietz-Ortiz, Maria; Gestel, Cornelis A.M. van [VU Univ., Amsterdam (Netherlands). Dept. of Animal Ecology

    2011-10-15

    A contaminated soil was amended to reduce bioavailability of metals (As, Cd, Cu, Pb, and Zn) and to modify its potential environmental impacts. Reproduction toxicity tests using two different soil invertebrates, Enchytraeus crypticus and Folsomia candida, were used to evaluate efficiency of soil amendments to reduce metal availability. This study has been carried out on a very contaminated soil from El Arteal mining district (SE Spain). The amendments used were marble sludge from the cutting and polishing of marble, compost from greenhouse wastes, and synthetic iron oxides. Soils were analyzed for cation exchange capacity, organic carbon and calcium carbonate content, particle size distribution, pH, electrical conductivity, and total metal content. Porewater and 0.01 M CaCl{sub 2}-extractable concentrations were measured in unamended and amended soils. Soil organisms were exposed to all treatments and to untreated soil. The parameters evaluated in both bioassays were survival and reproduction. All treatments decreased the porewater and CaCl{sub 2}-extractable concentrations of Zn, Pb, Cd, and Cu. The amendments increased survival and reproduction of E. crypticus, reducing toxicity. Survival of F. candida was also increased by the treatments; its reproduction did, however, not improve. These differences may be due to other factors that may affect collembolan reproduction. The different sensitivity of each test organism to some soil properties such as pH and electrical conductivity, which can affect reproduction, should be considered before interpreting results from bioassays focussed on toxicity due to pollutants. Reproduction toxicity bioassays with soil invertebrates are a good complement of chemical analysis to properly assess the ecological risk of remediation processes. Organisms with different exposure routes and different sensitivities to soil properties should be used simultaneously to assess the environmental risk of metal-contaminated sites and to evaluate

  15. Air Pollution from Livestock Farms is Associated with Airway Obstruction in Neighboring Residents

    NARCIS (Netherlands)

    Borlée, Floor|info:eu-repo/dai/nl/315138661; Yzermans, C Joris; Aalders, Bernadette; Rooijackers, Jos; Krop, Esmeralda|info:eu-repo/dai/nl/30482383X; Maassen, Catharina B M; Schellevis, François; Brunekreef, Bert|info:eu-repo/dai/nl/067548180; Heederik, Dick|info:eu-repo/dai/nl/072910542; Smit, Lidwien A M|info:eu-repo/dai/nl/311470882

    2017-01-01

    RATIONALE: Livestock farm emissions may not only affect respiratory health of farmers but also of neighboring residents. OBJECTIVES: To explore associations between both spatial and temporal variation in pollutant emissions from livestock farms and lung function in a general, non-farming, rural

  16. Air pollution from livestock farms is associated with airway obstruction in neighboring residents.

    NARCIS (Netherlands)

    Borlée, F.; Yzermans, C.J.; Aalders, B.; Rooijackers, J.; Krop, E.; Maassen, C.B.M.; Schellevis, F.; Brunekreef, B.; Heederik, D.; Smit, L.A.M.

    2017-01-01

    Rationale: Livestock farm emissions may not only affect respiratory health of farmers but also of neighboring residents. Objectives: To explore associations between both spatial and temporal variation in pollutant emissions from livestock farms and lung function in a general, non-farming, rural

  17. Dose distribution in the thyroid and neighboring regions in therapy with 131I

    International Nuclear Information System (INIS)

    Monteiro, Rommel Barbosa; Bonifacio, Daniel Alexandre Baptista; Sa, Lidia Vasconcellos de

    2013-01-01

    In this work, simulations were performed with two types of computer simulators: the MIRD phantom and voxel phantom MASH, both of type adult male and in the standing position, coupled to the computational tool GATE (Geant4 Application for Tomographic Emission), to obtain the dose deposited in thyroid and neighboring regions

  18. Moderate-resolution data and gradient nearest neighbor imputation for regional-national risk assessment

    Science.gov (United States)

    Kenneth B. Jr. Pierce; C. Kenneth Brewer; Janet L. Ohmann

    2010-01-01

    This study was designed to test the feasibility of combining a method designed to populate pixels with inventory plot data at the 30-m scale with a new national predictor data set. The new national predictor data set was developed by the USDA Forest Service Remote Sensing Applications Center (hereafter RSAC) at the 250-m scale. Gradient Nearest Neighbor (GNN)...

  19. Estimating forest attribute parameters for small areas using nearest neighbors techniques

    Science.gov (United States)

    Ronald E. McRoberts

    2012-01-01

    Nearest neighbors techniques have become extremely popular, particularly for use with forest inventory data. With these techniques, a population unit prediction is calculated as a linear combination of observations for a selected number of population units in a sample that are most similar, or nearest, in a space of ancillary variables to the population unit requiring...

  20. Stuttering Attitudes among Turkish Family Generations and Neighbors from Representative Samples

    Science.gov (United States)

    Ozdemir, R. Sertan; St. Louis, Kenneth O.; Topbas, Seyhun

    2011-01-01

    Purpose: Attitudes toward stuttering, measured by the "Public Opinion Survey of Human Attributes-Stuttering" ("POSHA-S"), are compared among (a) two different representative samples; (b) family generations (children, parents, and either grandparents or uncles and aunts) and neighbors; (c) children, parents, grandparents/adult…

  1. Living alongside more affluent neighbors predicts greater involvement in antisocial behavior among low-income boys.

    Science.gov (United States)

    Odgers, Candice L; Donley, Sachiko; Caspi, Avshalom; Bates, Christopher J; Moffitt, Terrie E

    2015-10-01

    The creation of economically mixed communities has been proposed as one way to improve the life outcomes of children growing up in poverty. However, whether low-income children benefit from living alongside more affluent neighbors is unknown. Prospectively gathered data on over 1,600 children from the Environmental Risk (E-Risk) Longitudinal Twin Study living in urban environments is used to test whether living alongside more affluent neighbors (measured via high-resolution geo-spatial indices) predicts low-income children's antisocial behavior (reported by mothers and teachers at the ages of 5, 7, 10, and 12). Results indicated that low-income boys (but not girls) surrounded by more affluent neighbors had higher levels of antisocial behavior than their peers embedded in concentrated poverty. The negative effect of growing up alongside more affluent neighbors on low-income boys' antisocial behavior held across childhood and after controlling for key neighborhood and family-level factors. Findings suggest that efforts to create more economically mixed communities for children, if not properly supported, may have iatrogenic effects on boys' antisocial behavior. © 2015 Association for Child and Adolescent Mental Health.

  2. Probability distributions for first neighbor distances between resonances that belong to two different families

    International Nuclear Information System (INIS)

    Difilippo, F.C.

    1994-01-01

    For a mixture of two families of resonances, we found the probability distribution for the distance, as first neighbors, between resonances that belong to different families. Integration of this distribution gives the probability of accidental overlapping of resonances of one isotope by resonances of the other, provided that the resonances of each isotope belong to a single family. (author)

  3. Dose distribution in the thyroid and neighboring regions in therapy with {sup 131}I

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Rommel Barbosa; Bonifacio, Daniel Alexandre Baptista; Sa, Lidia Vasconcellos de [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    In this work, simulations were performed with two types of computer simulators: the MIRD phantom and voxel phantom MASH, both of type adult male and in the standing position, coupled to the computational tool GATE (Geant4 Application for Tomographic Emission), to obtain the dose deposited in thyroid and neighboring regions.

  4. Who's Watching the Babies? Improving the Quality of Family, Friend, and Neighbor Child Care

    Science.gov (United States)

    Powell, Douglas R.

    2008-01-01

    One of the important influences on a child's development is the quality of his or her early care and education experiences. It is estimated that more than 1 million children in the U.S. are cared for while their parents are at work by nonlicensed caregivers who are family, friends, or neighbors - and these caregivers can be difficult to reach…

  5. Estimating cavity tree and snag abundance using negative binomial regression models and nearest neighbor imputation methods

    Science.gov (United States)

    Bianca N.I. Eskelson; Hailemariam Temesgen; Tara M. Barrett

    2009-01-01

    Cavity tree and snag abundance data are highly variable and contain many zero observations. We predict cavity tree and snag abundance from variables that are readily available from forest cover maps or remotely sensed data using negative binomial (NB), zero-inflated NB, and zero-altered NB (ZANB) regression models as well as nearest neighbor (NN) imputation methods....

  6. Optimizing Neighbor Discovery for Ad hoc Networks based on the Bluetooth PAN Profile

    DEFF Research Database (Denmark)

    Kuijpers, Gerben; Nielsen, Thomas Toftegaard; Prasad, Ramjee

    2002-01-01

    . This paper introduces a neighbor discovery mechanism that utilizes the resources in the Bluetooth PAN profile more efficient. The performance of the new mechanism is investigated using a IPv6 network simulator and compared with emulated broadcasting. It is shown that the signaling overhead can...

  7. Loving All Your Neighbors: Why Community Colleges Need the Academic Study of Religion

    Science.gov (United States)

    Maley, Melissa

    2013-01-01

    This chapter explains how the study of world religions prepares the community college student to become a better citizen, worker, and neighbor. The effective middle between the pitfalls of religious relativism and religious dominance in a world religions classroom is central to this discussion of teaching critical thinking, empathy, and…

  8. The indirect effects of cheatgrass invasion: Grasshopper herbivory on native grasses determined by neighboring cheatgrass abundance

    Science.gov (United States)

    Julie Beckstead; Susan E. Meyer; Carol K. Augsperger

    2008-01-01

    Invasion biology has focused on the direct effects of plant invasion and has generally overlooked indirect interactions. Here we link theories of invasion biology and herbivory to explore an indirect effect of one invading species on associational herbivory (the effect of neighboring plants on herbivory) of native species. We studied a Great Basin shadscale (...

  9. Mi Vecina es una Mujer Colpeada (My Neighbor Is a Battered Woman).

    Science.gov (United States)

    Howard, Melissa

    This book, the Spanish version of "My Neighbor is a Battered Woman," is intended as a general introduction to the problems of battered women. The format for part 1 consists of the presentation of facts about wife beating, i.e., who are victims, characteristics of batterers, the environment in which family violence exists, and services…

  10. Improved Nearest Neighbor Methods for Gamma Photon Interaction Position Determination in Monolithic Scintillator PET Detectors

    NARCIS (Netherlands)

    van Dam, Herman T.; Seifert, Stefan; Vinke, Ruud; Dendooven, Peter; Lohner, Herbert; Beekman, Freek J.; Schaart, Dennis R.

    2011-01-01

    Monolithic scintillator detectors have been shown to provide good performance and to have various practical advantages for use in PET systems. Excellent results for the gamma photon interaction position determination in these detectors have been obtained by means of the k-nearest neighbor (k-NN)

  11. Nearest-neighbor interactions, habitat fragmentation, and the persistence of host-pathogen systems.

    Science.gov (United States)

    Wodarz, Dominik; Sun, Zhiying; Lau, John W; Komarova, Natalia L

    2013-09-01

    Spatial interactions are known to promote stability and persistence in enemy-victim interactions if instability and extinction occur in well-mixed settings. We investigate the effect of spatial interactions in the opposite case, where populations can persist in well-mixed systems. A stochastic agent-based model of host-pathogen dynamics is considered that describes nearest-neighbor interactions in an undivided habitat. Contrary to previous notions, we find that in this setting, spatial interactions in fact promote extinction. The reason is that, in contrast to the mass-action system, the outcome of the nearest-neighbor model is governed by dynamics in small "local neighborhoods." This is an abstraction that describes interactions in a minimal grid consisting of an individual plus its nearest neighbors. The small size of this characteristic scale accounts for the higher extinction probabilities. Hence, nearest-neighbor interactions in a continuous habitat lead to outcomes reminiscent of a fragmented habitat, which is underlined further with a metapopulation model that explicitly assumes habitat fragmentation. Beyond host-pathogen dynamics, axiomatic modeling shows that our results hold for generic enemy-victim interactions under specified assumptions. These results are used to interpret a set of published experiments that provide a first step toward model testing and are discussed in the context of the literature.

  12. Numerical Simulation of the Diffusion Processes in Nanoelectrode Arrays Using an Axial Neighbor Symmetry Approximation.

    Science.gov (United States)

    Peinetti, Ana Sol; Gilardoni, Rodrigo S; Mizrahi, Martín; Requejo, Felix G; González, Graciela A; Battaglini, Fernando

    2016-06-07

    Nanoelectrode arrays have introduced a complete new battery of devices with fascinating electrocatalytic, sensitivity, and selectivity properties. To understand and predict the electrochemical response of these arrays, a theoretical framework is needed. Cyclic voltammetry is a well-fitted experimental technique to understand the undergoing diffusion and kinetics processes. Previous works describing microelectrode arrays have exploited the interelectrode distance to simulate its behavior as the summation of individual electrodes. This approach becomes limited when the size of the electrodes decreases to the nanometer scale due to their strong radial effect with the consequent overlapping of the diffusional fields. In this work, we present a computational model able to simulate the electrochemical behavior of arrays working either as the summation of individual electrodes or being affected by the overlapping of the diffusional fields without previous considerations. Our computational model relays in dividing a regular electrode array in cells. In each of them, there is a central electrode surrounded by neighbor electrodes; these neighbor electrodes are transformed in a ring maintaining the same active electrode area than the summation of the closest neighbor electrodes. Using this axial neighbor symmetry approximation, the problem acquires a cylindrical symmetry, being applicable to any diffusion pattern. The model is validated against micro- and nanoelectrode arrays showing its ability to predict their behavior and therefore to be used as a designing tool.

  13. Collective Behaviors of Mobile Robots Beyond the Nearest Neighbor Rules With Switching Topology.

    Science.gov (United States)

    Ning, Boda; Han, Qing-Long; Zuo, Zongyu; Jin, Jiong; Zheng, Jinchuan

    2018-05-01

    This paper is concerned with the collective behaviors of robots beyond the nearest neighbor rules, i.e., dispersion and flocking, when robots interact with others by applying an acute angle test (AAT)-based interaction rule. Different from a conventional nearest neighbor rule or its variations, the AAT-based interaction rule allows interactions with some far-neighbors and excludes unnecessary nearest neighbors. The resulting dispersion and flocking hold the advantages of scalability, connectivity, robustness, and effective area coverage. For the dispersion, a spring-like controller is proposed to achieve collision-free coordination. With switching topology, a new fixed-time consensus-based energy function is developed to guarantee the system stability. An upper bound of settling time for energy consensus is obtained, and a uniform time interval is accordingly set so that energy distribution is conducted in a fair manner. For the flocking, based on a class of generalized potential functions taking nonsmooth switching into account, a new controller is proposed to ensure that the same velocity for all robots is eventually reached. A co-optimizing problem is further investigated to accomplish additional tasks, such as enhancing communication performance, while maintaining the collective behaviors of mobile robots. Simulation results are presented to show the effectiveness of the theoretical results.

  14. Statistical Modeling of Turbulent Dispersion using a Near-Neighbor Implementation of a Local Mixing Model

    Science.gov (United States)

    Viswanathan, Sharadha; Pope, Stephen B.

    2007-11-01

    Probability density function (PDF) calculations are reported for the dispersion from line sources in isotropic turbulence. These flows pose a significant challenge to statistical models, because the scalar length scale (of the initial plume) is much smaller than the turbulence integral scale. The PDF calculations are based on a new near-neighbor implementation of the interaction by exchange with the conditional mean (IECM) mixing model. The calculations are compared to the experimental data of Warhaft (1984) on single and pairs of line sources, and with the previous calculations of Sawford (2004). This establishes the accuracy of the new implementation of IECM. An array of line sources is also considered with comparison to the experimental data of Warhaft & Lumley (1978), which show the dependence of the scalar variance decay rate on the array spacing relative to the turbulence integral scale. The near-neighbor implementation is applicable to other local mixing models, as arise, for example, in multiple mapping conditioning (Klimenko & Pope 2003). In the particle method used to solve the modeled PDF equation, the near-neighbor implementation results in a particle's mixing with just one or two near neighbors (in the relevant space), and hence maximizes the localness of mixing.

  15. Transfer-Efficient Face Routing Using the Planar Graphs of Neighbors in High Density WSNs

    Directory of Open Access Journals (Sweden)

    Eun-Seok Cho

    2017-10-01

    Full Text Available Face routing has been adopted in wireless sensor networks (WSNs where topological changes occur frequently or maintaining full network information is difficult. For message forwarding in networks, a planar graph is used to prevent looping, and because long edges are removed by planarization and the resulting planar graph is composed of short edges, and messages are forwarded along multiple nodes connected by them even though they can be forwarded directly. To solve this, face routing using information on all nodes within 2-hop range was adopted to forward messages directly to the farthest node within radio range. However, as the density of the nodes increases, network performance plunges because message transfer nodes receive and process increased node information. To deal with this problem, we propose a new face routing using the planar graphs of neighboring nodes to improve transfer efficiency. It forwards a message directly to the farthest neighbor and reduces loads and processing time by distributing network graph construction and planarization to the neighbors. It also decreases the amount of location information to be transmitted by sending information on the planar graph nodes rather than on all neighboring nodes. Simulation results show that it significantly improves transfer efficiency.

  16. DSSTOX NATIONAL TOXICOLOGY PROGRAM BIOASSAY ON-LINE DATABASE STRUCTURE-INDEX LOCATOR FILE: SDF FILE AND DOCUMENTATION

    Science.gov (United States)

    NTPBSI: National Toxicology Program Bioassay On-line Database Structure-Index Locator File. Database contains the results collected on approxiately 300 toxicity studies from shorter duration test and from genetic toxicity studies, both in vitro and in vivo tests.

  17. Use of Chemical Indicators and Bioassays in Bottom Sediment Ecological Risk Assessment.

    Science.gov (United States)

    Tarnawski, Marek; Baran, Agnieszka

    2018-02-27

    This study is was designed to assess the ecological risk associated with chemical pollution caused by heavy metals and PAHs on the basis of their ecotoxicological properties in sediments collected from the Rzeszów dam reservoir (Poland). The sediment samples were collected from three sampling stations: S1-inlet, backwater station, S2-middle of reservoir, S3 outlet, near the dam. The sediments' toxicity was evaluated using a battery of bioassays (Phytotoxkit, Phytotestkit, Ostracodtoxkit F, and Microtox). The highest content of metals (120.5 mg Zn; 22.65 mg Pb; 8.20 mg Cd ∙ kg -1 dw) and all PAHs (∑9361 μg ∙ kg -1 dw) in sediments was found at station S1. The lowest content of metals (86.72 mg Zn; 18.07 mg Cu; 17.20 mg Pb; 3.62 mg Cu; 28.78 mg Ni; 30.52 mg Cr ∙ kg -1 dw) and PAHs (∑4390 μg ∙ kg -1 dw) was found in the sediment from station S2. The ecological risk assessment of the six metals and eight PAHs revealed a high potential toxicity in sediments from stations S1 (PECq = 0.69) and S3 (PECq = 0.56) and a low potential toxicity in sediments from station S2 (PECq = 0.38). The studies also showed the actual toxicity of sediments for the test organisms. The sediment pore water was least toxic compared to the whole sediment: solid phases > whole sediment > pore water. The most sensitive organism for metals and PAHs in bottom sediments was Lepidium sativum, and in pore water-Sorghum saccharatum. The concentration of metals and PAHs in bottom sediments generally did not affect the toxicity for other organisms. Clay content and organic C content are likely to be important factors, which control heavy metal and PAH concentrations in the sediments. Data analysis by PCA found the same origin of metals as well as PAHs-mainly anthropogenic sources. The obtained information demonstrated the need to integrate ecotoxicological and chemical methods for an appropriate ecological risk assessment.

  18. PAH exposure through soil ingestion: Combining digestion models and bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Wiele, T.R. van de; Verstraete, W. [Ghent University (BE).Laboratory Microbial Ecology and Technology (LabMET); Siciliano, S.D. [University of Saskatchewan (Canada). Department of Soil Science

    2003-07-01

    Exposure to environmental contaminants through soil ingestion is an important issue in current health risk assessment. Polycyclic aromatic hydrocarbons (PAH) or their metabolites pose risks to humans due to their toxic, mutagenic, carcinogenic or even (anti)estrogenic properties. PAH mobilization from a soil matrix (49.1{+-}1.5 mg PAH/kg DW) was assessed using a Simulator of the Human Intestinal Microbial Ecosystem (SHIME). PAH GC-MS analysis was performed on the pellet and supernatant of SHIME digests and gave 101, 92, 89 and 97% recovery for water, stomach, duodenal and colon digests, respectively. PAH release was highest for the water extract (0.51%) and the stomach digestion (0.44%). Lower mobilized fractions in the duodenum (0.13%) and colon (0.30%) digests could be attributed to PAH complexation with bile salts, dissolved organic matter or colon microbiota. The digestion model provides us with relevant information to what extent soil bound PAHs are mobilized in the gastrointestinal tract and thus reach the gut wall, prior to absorption. (orig.)

  19. Interval valued fuzzy sets k-nearest neighbors classifier for finger vein recognition

    Science.gov (United States)

    Mukahar, Nordiana; Affendi Rosdi, Bakhtiar

    2017-09-01

    In nearest neighbor classification, fuzzy sets can be used to model the degree of membership of each instance to the classes of the problem. Although the fuzzy memberships can be set by analyzing local data around each instance, there may be still a lack of knowledge associated with the assignation of a single value to the membership. This is caused by the requirement of determining in advance two fixed parameters: k, in the definition of the initial membership values and m, in the computation of the votes of neighbors. Thus, the two fixed parameters only allow the flexibility of membership using a single value only. To overcome this drawback, a new approach of interval valued fuzzy sets k-nearest neighbors (IVFKNN) that incorporating interval valued fuzzy sets for computing the membership of instance is presented that allows membership values to be defined using a lower bound and an upper bound with the length of interval. The intervals concept is introduced to assign membership for each instance in training set and represents membership as an array of intervals. The intervals also considered the computation of the votes with the length of interval. In order to assess the classification performance of the IVFKNN classifier, it is compared with the competing classifiers, such as k-nearest neighbors (KNN) and fuzzy k-nearest neighbors (FKNN), in terms of the classification accuracy on publicly available Finger Vein USM (FV-USM) image database which was collected from 123 volunteers. The experimental results remark the strong performance of IVFKNN compared with the competing classifiers and show the best improvement in classification accuracy in all cases.

  20. Identification of Lilial as a fragrance sensitizer in a perfume by bioassay-guided chemical fractionation and structure-activity relationships.

    Science.gov (United States)

    Arnau, E G; Andersen, K E; Bruze, M; Frosch, P J; Johansen, J D; Menné, T; Rastogi, S C; White, I R; Lepoittevin, J P

    2000-12-01

    Fragrance materials are among the most common causes of allergic contact dermatitis. The aim of this study was to identify in a perfume fragrance allergens not included in the fragrance mix, by use of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships (SARs). The basis for the investigation was a 45-year-old woman allergic to her own perfume. She had a negative patch test to the fragrance mix and agreed to participate in the study. Chemical fractionation of the perfume concentrate was used for repeated patch testing and/or repeated open application test on the pre-sensitized patient. The chemical composition of the fractions giving a positive patch-test response and repeated open application test reactions was obtained by gas chromatography-mass spectrometry. From the compounds identified, those that contained a "structural alert" in their chemical structure, indicating an ability to modify skin proteins and thus behave as a skin sensitizer, were tested on the patient. The patient reacted positively to the synthetic fragrance p-t-butyl-alpha-methylhydrocinnamic aldehyde (Lilial), a widely used fragrance compound not present in the fragrance mix. The combination of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships seems to be a valuable tool for the investigation of contact allergy to fragrance materials.

  1. Radiochemical determination of strontium-90 and cesium-137 in waters of the Pacific Ocean and its neighboring seas

    International Nuclear Information System (INIS)

    Borisenko, G.S.; Kandinskii, P.A.; Gedeonov, L.I.; Ivanova, L.M.; Petrov, A.A.

    1987-01-01

    Depending on the salinity of the water, two versions of strontium-90 and cesium-137 concentration from water samples are presented. Cesium-137 was concentrated by precipitating sparingly soluble mixed hexacyanoferrates (II), and strontium-90 by precipitating carbonates together with calcium. A scheme has been given for radiochemical analysis of the concentrates. Strontium-90 and cesium-137 contents in the waters of the Pacific Ocean and its neighboring seas have been determined by the radiochemical method described. The levels of radionuclide content in the water and atmospheric precipitations have been shown to be inter-related. Strontium-90 and cesium-137 contents in the surface water of the northwestern Pacific were found to be much lower in 1980 than in the early seventies. The area of technogenic radioactive pollution was found to persist in the region of the Columbia mouth into the Pacific Ocean

  2. A rapid and high-throughput quantum dots bioassay for monitoring of perfluorooctane sulfonate in environmental water samples

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jiong; Wan Yanjian; Li Yuanyuan; Zhang Qiongfang; Xu Shunqing [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China); Zhu Huijun [Cranfield Health, Cranfield University, Kempston, Bedfordshire, MK43 0AL (United Kingdom); Shu Baihua, E-mail: shubaihua@hotmail.com [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China)

    2011-05-15

    Currently HPLC/MS is the state of the art tool for environmental/drinking water perfluorooctane sulfonate (PFOS) monitoring. PFOS can bind to peroxisomal proliferator-activated receptor-alpha (PPAR{alpha}), which forms heterodimers with retinoid X receptors (RXRs) and binds to PPAR response elements. In this bioassay free PFOS in water samples competes with immobilized PFOS in ELISA plates for a given amount of PPAR{alpha}-RXR{alpha}. It can be determined indirectly by immobilizing PPAR{alpha}-RXR{alpha}-PFOS complex to another plate coated with PPAR{alpha} antibody and subsequent measuring the level of PPAR{alpha}-RXR{alpha} by using biotin-modified PPAR{alpha}-RXR{alpha} probes-quantum dots-streptavidin detection system. The rapid and high-throughput bioassay demonstrated a detection limit of 2.5 ng L{sup -1} with linear range between 2.5 ng L{sup -1} and 75 ng L{sup -1}. Detection results of environmental water samples were highly consistent between the bioassay and HPLC/MS. - We developed a rapid and high-throughput bioassay for monitoring of PFOS in environmental water samples. - Highlights: > We developed a rapid and high-throughput bioassay for monitoring of PFOS in water. > We detected the PFOS concentration of water samples by two methods. > The bioassay is effective for evaluating PFOS contamination level.

  3. Development of a bioassay to screen for chemicals mimicking the anti-aging effects of calorie restriction

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Takuya, E-mail: takuya@nagasaki-u.ac.jp [Department of Investigative Pathology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Tsuchiya, Tomoshi [Division of Surgical Oncology, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8501 (Japan); Komatsu, Toshimitsu; Mori, Ryoichi; Hayashi, Hiroko [Department of Investigative Pathology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Shimano, Hitoshi [Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba Ibaraki 305-8575 (Japan); Spindler, Stephen R. [Department of Biochemistry, Room 5478, Boyce Hall, University of California - Riverside, Riverside, CA 92521 (United States); Shimokawa, Isao [Department of Investigative Pathology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)

    2010-10-15

    Research highlights: {yields} We identified four sequence motifs lying upstream of putative pro-longevity genes. {yields} One of these motifs binds to HNF-4{alpha}. {yields} HNF-4{alpha}/PGC-1{alpha} could up-regulate the transcription of a reporter gene linked to this motif. {yields} The reporter system described here could be used to screen candidate anti-aging molecules. -- Abstract: Suppression of the growth hormone/insulin-like growth factor-I pathway in Ames dwarf (DF) mice, and caloric restriction (CR) in normal mice extends lifespan and delays the onset of age-related disorders. In combination, these interventions have an additive effect on lifespan in Ames DF mice. Therefore, common signaling pathways regulated by DF and CR could have additive effects on longevity. In this study, we tried to identity the signaling mechanism and develop a system to assess pro-longevity status in cells and mice. We previously identified genes up-regulated in the liver of DF and CR mice by DNA microarray analysis. Motif analysis of the upstream sequences of those genes revealed four major consensus sequence motifs, which have been named dwarfism and calorie restriction-responsive elements (DFCR-REs). One of the synthesized sequences bound to hepatocyte nuclear factor-4{alpha} (HNF-4{alpha}), an important transcription factor involved in liver metabolism. Furthermore, using this sequence information, we developed a highly sensitive bioassay to identify chemicals mimicking the anti-aging effects of CR. When the reporter construct, containing an element upstream of a secreted alkaline phosphatase (SEAP) gene, was co-transfected with HNF-4{alpha} and its regulator peroxisome proliferator-activated receptor (PPAR) {gamma} coactivator-1{alpha} (PGC-1{alpha}), SEAP activity was increased compared with untransfected controls. Moreover, transient transgenic mice established using this construct showed increased SEAP activity in CR mice compared with ad libitum-fed mice. These data

  4. GPR measurements and estimation for road subgrade damage caused by neighboring train vibration load

    Science.gov (United States)

    Zhao, Yonghui; Lu, Gang; Ge, Shuangcheng

    2015-04-01

    Generally, road can be simplified as a three-layer structure, including subgrade, subbase and pavement. Subgrade is the native material underneath a constructed road. It is commonly compacted before the road construction, and sometimes stabilized by the addition of asphalt, lime or other modifiers. As the mainly supporting structure, subgrade damage would lead in pavement settlement, displacement and crack. Assessment and monitoring of the subgrade condition currently involves trial pitting and subgrade sampling. However there is a practical limit on spatial density at which trail pits and cores can be taken. Ground penetrating radar (GPR) has been widely used to characterize highway pavement profiling, concrete structure inspection and railroad track ballast estimation. GPR can improve the economics of road maintenance. Long-term train vibration load might seriously influence the stability of the subgrade of neighboring road. Pavement settlement and obvious cracks have been found at a municipal road cross-under a railway with culvert box method. GPR test was conducted to estimate the subgrade and soil within 2.0 m depth for the further road maintenance. Two survey lines were designed in each lane, and total 12 GPR sections have been implemented. Considering both the penetrating range and the resolution, a antenna with a 500 MHz central frequency was chosen for on-site GPR data collection. For data acquisition, we used the default operating environment and scanning parameters for the RAMAC system: 60kHz transmission rate, 50 ns time window, 1024 samples per scan and 0.1 m step-size. Continuous operation was used; the antenna was placed on the road surface and slowly moved along the road. The strong surrounding disturbance related to railroad and attachments, might decrease the reliability of interpretation results. Some routine process methods (including the background removing, filtering) have been applied to suppress the background noise. Additionally, attribute

  5. Genetic mouse embryo assay: improving performance and quality testing for assisted reproductive technology (ART) with a functional bioassay.

    Science.gov (United States)

    Gilbert, Rebecca S; Nunez, Brandy; Sakurai, Kumi; Fielder, Thomas; Ni, Hsiao-Tzu

    2016-03-24

    Growing concerns about safety of ART on human gametes, embryos, clinical outcomes and long-term health of offspring require improved methods of risk assessment to provide functionally relevant assays for quality control testing and pre-clinical studies prior to clinical implementation. The one-cell mouse embryo assay (MEA) is the most widely used for development and quality testing of human ART products; however, concerns exist due to the insensitivity/variability of this bioassay which lacks standardization and involves subjective analysis by morphology alone rather than functional analysis of the developing embryos. We hypothesized that improvements to MEA by the use of functional molecular biomarkers could enhance sensitivity and improve detection of suboptimal materials/conditions. Fresh one-cell transgenic mouse embryos with green fluorescent protein (GFP) expression driven by Pou6f1 or Cdx2 control elements were harvested and cultured to blastocysts in varied test and control conditions to compare assessment by standard morphology alone versus the added dynamic expression of GFP for screening and selection of critical raw materials and detection of suboptimal culture conditions. Transgenic mouse embryos expressing functionally relevant biomarkers of normal early embryo development can be used to monitor the developmental impact of culture conditions. This novel approach provides a superior MEA that is more meaningful and sensitive for detection of embryotoxicity than morphological assessment alone.

  6. A two-step nearest neighbors algorithm using satellite imagery for predicting forest structure within species composition classes

    Science.gov (United States)

    Ronald E. McRoberts

    2009-01-01

    Nearest neighbors techniques have been shown to be useful for predicting multiple forest attributes from forest inventory and Landsat satellite image data. However, in regions lacking good digital land cover information, nearest neighbors selected to predict continuous variables such as tree volume must be selected without regard to relevant categorical variables such...

  7. 75 FR 62412 - Notice of Proposed Information Collection: Comment Request; HUD-Owned Real Estate-Good Neighbor...

    Science.gov (United States)

    2010-10-08

    ... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5380-N-36] Notice of Proposed Information Collection: Comment Request; HUD- Owned Real Estate-Good Neighbor Next Door Program AGENCY: Office... information: Title of Proposal: HUD-Owned Real Estate-Good Neighbor Next Door Program. OMB Control Number, if...

  8. Determination of bacteriocin activity with bioassays carried out on solid and liquid substrates: assessing the factor "indicator microorganism"

    Directory of Open Access Journals (Sweden)

    Ambrosiadis Ioannis

    2006-10-01

    Full Text Available Abstract Background Successful application of growth inhibition techniques for quantitative determination of bacteriocins relies on the sensitivity of the applied indicator microorganism to the bacteriocin to which is exposed. However, information on indicator microorganisms' performance and comparisons in bacteriocin determination with bioassays is almost non-existing in the literature. The aim of the present work was to evaluate the parameter "indicator microorganism" in bioassays carried out on solid -agar diffusion assay- and liquid -turbidometric assay- substrates, applied in the quantification of the most studied bacteriocin nisin. Results The performance of characterized microorganisms of known sources, belonging to the genera of Lactobacillus, Pediococcus, Micrococcus and Leuconostoc, has been assessed in this work in the assays of plate agar diffusion and turbidometry. Dose responses and sensitivities were examined and compared over a range of assay variables in standard bacteriocin solutions, fermentation broth filtrates and processed food samples. Measurements on inhibition zones produced on agar plates were made by means of digital image analysis. The data produced were analyzed statistically using the ANOVA technique and pairwise comparisons tests. Sensitivity limits and linearity of responses to bacteriocin varied significantly among different test-microorganisms in both applied methods, the lower sensitivity limits depending on both the test-microorganism and the applied method. In both methods, however, only two of the nine tested microorganisms (Lactobacillus curvatus ATCC 51436 and Pediococcus acidilactici ATCC 25740 were sensitive to very low concentrations of the bacteriocin and produced a linear-type of response in all kinds of samples used in this work. In all cases, very low bacteriocin concentrations, e.g. 1 IU/ml nisin, were more accurately determined in the turbidometric assay. Conclusion The present work shows that in

  9. Sub-millisecond firing synchrony of closely neighboring pyramidal neurons in hippocampal CA1 of rats during delayed non-matching to sample task

    Directory of Open Access Journals (Sweden)

    Susumu Takahashi

    2009-09-01

    Full Text Available Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes, we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison and external (stimulus input and motor output events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information—as represented by the firing rate modulations—to downstream neurons.

  10. Formation of tight junctions between neighboring podocytes is an early ultrastructural feature in experimental crescentic glomerulonephritis

    Directory of Open Access Journals (Sweden)

    Succar L

    2016-11-01

    Full Text Available Lena Succar,1 Ross A Boadle,2 David C Harris,1,3 Gopala K Rangan1,3 1Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, 2Electron Microscopy Laboratory, Institute of Clinical Pathology and Medical Research, Westmead Hospital, 3Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Westmead, Sydney, NSW, Australia Purpose: In crescentic glomerulonephritis (CGN, the development of cellular bridges between podocytes and parietal epithelial cells (PECs triggers glomerular crescent formation. However, the sequential changes in glomerular ultrastructure in CGN are not well defined. This study investigated the time course of glomerular ultrastructure in experimental CGN. Methods: Transmission electron microscopy (TEM was performed using kidney samples from rats with nephrotoxic serum nephritis (NSN from day 1 to day 14. Morphometric analysis was conducted on randomly selected glomeruli captured on TEM digital images. Results: On day 1 of NSN, there was widespread formation of focal contacts between the cell bodies of neighboring podocytes, and tight junctions were evident at the site of cell-to-cell contact. This was confirmed by the increased expression of the tight junction molecule, zonula occludens-1 (ZO-1, which localized to the points of podocyte cell–cell body contact. On day 2, the interpodocyte distance decreased and the glomerular basement membrane thickness increased. Foot process effacement (FPE was segmental on day 3 and diffuse by day 5, accompanied by the formation of podocyte cellular bridges with Bowman’s capsule, as confirmed by a decrease in podocyte-to-PEC distance. Fibrinoid necrosis and cellular crescents were evident in all glomeruli by days 7 and 14. In vitro, the exposure of podocytes to macrophage-conditioned media altered cellular morphology and caused an intracellular redistribution of ZO-1. Conclusion: The formation of tight

  11. A novel hybrid classification model of genetic algorithms, modified k-Nearest Neighbor and developed backpropagation neural network.

    Directory of Open Access Journals (Sweden)

    Nader Salari

    Full Text Available Among numerous artificial intelligence approaches, k-Nearest Neighbor algorithms, genetic algorithms, and artificial neural networks are considered as the most common and effective methods in classification problems in numerous studies. In the present study, the results of the implementation of a novel hybrid feature selection-classification model using the above mentioned methods are presented. The purpose is benefitting from the synergies obtained from combining these technologies for the development of classification models. Such a combination creates an opportunity to invest in the strength of each algorithm, and is an approach to make up for their deficiencies. To develop proposed model, with the aim of obtaining the best array of features, first, feature ranking techniques such as the Fisher's discriminant ratio and class separability criteria were used to prioritize features. Second, the obtained results that included arrays of the top-ranked features were used as the initial population of a genetic algorithm to produce optimum arrays of features. Third, using a modified k-Nearest Neighbor method as well as an improved method of backpropagation neural networks, the classification process was advanced based on optimum arrays of the features selected by genetic algorithms. The performance of the proposed model was compared with thirteen well-known classification models based on seven datasets. Furthermore, the statistical analysis was performed using the Friedman test followed by post-hoc tests. The experimental findings indicated that the novel proposed hybrid model resulted in significantly better classification performance compared with all 13 classification methods. Finally, the performance results of the proposed model was benchmarked against the best ones reported as the state-of-the-art classifiers in terms of classification accuracy for the same data sets. The substantial findings of the comprehensive comparative study revealed that

  12. A Novel Hybrid Classification Model of Genetic Algorithms, Modified k-Nearest Neighbor and Developed Backpropagation Neural Network

    Science.gov (United States)

    Salari, Nader; Shohaimi, Shamarina; Najafi, Farid; Nallappan, Meenakshii; Karishnarajah, Isthrinayagy

    2014-01-01

    Among numerous artificial intelligence approaches, k-Nearest Neighbor algorithms, genetic algorithms, and artificial neural networks are considered as the most common and effective methods in classification problems in numerous studies. In the present study, the results of the implementation of a novel hybrid feature selection-classification model using the above mentioned methods are presented. The purpose is benefitting from the synergies obtained from combining these technologies for the development of classification models. Such a combination creates an opportunity to invest in the strength of each algorithm, and is an approach to make up for their deficiencies. To develop proposed model, with the aim of obtaining the best array of features, first, feature ranking techniques such as the Fisher's discriminant ratio and class separability criteria were used to prioritize features. Second, the obtained results that included arrays of the top-ranked features were used as the initial population of a genetic algorithm to produce optimum arrays of features. Third, using a modified k-Nearest Neighbor method as well as an improved method of backpropagation neural networks, the classification process was advanced based on optimum arrays of the features selected by genetic algorithms. The performance of the proposed model was compared with thirteen well-known classification models based on seven datasets. Furthermore, the statistical analysis was performed using the Friedman test followed by post-hoc tests. The experimental findings indicated that the novel proposed hybrid model resulted in significantly better classification performance compared with all 13 classification methods. Finally, the performance results of the proposed model was benchmarked against the best ones reported as the state-of-the-art classifiers in terms of classification accuracy for the same data sets. The substantial findings of the comprehensive comparative study revealed that performance of the

  13. Beam dynamics in high intensity cyclotrons including neighboring bunch effects: Model, implementation, and application

    Directory of Open Access Journals (Sweden)

    J. J. Yang (杨建俊

    2010-06-01

    Full Text Available Space-charge effects, being one of the most significant collective effects, play an important role in high intensity cyclotrons. However, for cyclotrons with small turn separation, other existing effects are of equal importance. Interactions of radially neighboring bunches are also present, but their combined effects have not yet been investigated in any great detail. In this paper, a new particle in the cell-based self-consistent numerical simulation model is presented for the first time. The model covers neighboring bunch effects and is implemented in the three-dimensional object-oriented parallel code OPAL-cycl, a flavor of the OPAL framework. We discuss this model together with its implementation and validation. Simulation results are presented from the PSI 590 MeV ring cyclotron in the context of the ongoing high intensity upgrade program, which aims to provide a beam power of 1.8 MW (CW at the target destination.

  14. Escape from competition: neighbors reduce Centaurea stoebe performance at home but not away.

    Science.gov (United States)

    Callaway, Ragan M; Waller, Lauren P; Diaconu, Alecu; Pal, Robert; Collins, Alexandra R; Mueller-Schaerer, Heinz; Maron, John L

    2011-12-01

    The greater abundance of some exotic plants in their nonnative ranges might be explained in part by biogeographic differences in the strength of competition, but these competitive effects have not been experimentally examined in the field. We compared the effects of neighbors on the growth and reproduction of spotted knapweed (Centaurea stoebe) in Europe, where it is native, and in Montana, where it is invasive. There were strong negative competitive effects of neighboring vegetation on C. stoebe growth and reproduction in Europe. In contrast, identical experiments in Montana resulted in insignificant impacts on C. stoebe. Although the mechanisms that produce this dramatic biogeographic difference in competitive outcome remain unknown, our results indicate that differences in net competitive interactions between ranges may contribute to the striking dominance of C. stoebe in parts of North America.

  15. A dynamic evolutionary clustering perspective: Community detection in signed networks by reconstructing neighbor sets

    Science.gov (United States)

    Chen, Jianrui; Wang, Hua; Wang, Lina; Liu, Weiwei

    2016-04-01

    Community detection in social networks has been intensively studied in recent years. In this paper, a novel similarity measurement is defined according to social balance theory for signed networks. Inter-community positive links are found and deleted due to their low similarity. The positive neighbor sets are reconstructed by this method. Then, differential equations are proposed to imitate the constantly changing states of nodes. Each node will update its state based on the difference between its state and average state of its positive neighbors. Nodes in the same community will evolve together with time and nodes in the different communities will evolve far away. Communities are detected ultimately when states of nodes are stable. Experiments on real world and synthetic networks are implemented to verify detection performance. The thorough comparisons demonstrate the presented method is more efficient than two acknowledged better algorithms.

  16. Multi-strategy based quantum cost reduction of linear nearest-neighbor quantum circuit

    Science.gov (United States)

    Tan, Ying-ying; Cheng, Xue-yun; Guan, Zhi-jin; Liu, Yang; Ma, Haiying

    2018-03-01

    With the development of reversible and quantum computing, study of reversible and quantum circuits has also developed rapidly. Due to physical constraints, most quantum circuits require quantum gates to interact on adjacent quantum bits. However, many existing quantum circuits nearest-neighbor have large quantum cost. Therefore, how to effectively reduce quantum cost is becoming a popular research topic. In this paper, we proposed multiple optimization strategies to reduce the quantum cost of the circuit, that is, we reduce quantum cost from MCT gates decomposition, nearest neighbor and circuit simplification, respectively. The experimental results show that the proposed strategies can effectively reduce the quantum cost, and the maximum optimization rate is 30.61% compared to the corresponding results.

  17. Quantum Algorithm for K-Nearest Neighbors Classification Based on the Metric of Hamming Distance

    Science.gov (United States)

    Ruan, Yue; Xue, Xiling; Liu, Heng; Tan, Jianing; Li, Xi

    2017-11-01

    K-nearest neighbors (KNN) algorithm is a common algorithm used for classification, and also a sub-routine in various complicated machine learning tasks. In this paper, we presented a quantum algorithm (QKNN) for implementing this algorithm based on the metric of Hamming distance. We put forward a quantum circuit for computing Hamming distance between testing sample and each feature vector in the training set. Taking advantage of this method, we realized a good analog for classical KNN algorithm by setting a distance threshold value t to select k - n e a r e s t neighbors. As a result, QKNN achieves O( n 3) performance which is only relevant to the dimension of feature vectors and high classification accuracy, outperforms Llyod's algorithm (Lloyd et al. 2013) and Wiebe's algorithm (Wiebe et al. 2014).

  18. Miniature-dispenser-based bioassay to evaluate the compatibility of powder formulations used in an entomovectoring approach.

    Science.gov (United States)

    Mommaerts, Veerle; Put, Kurt; Vandeven, Jessica; Smagghe, Guy

    2012-06-01

    Entomovectoring as a plant protection strategy demands the design of an appropriate bioassay to assess the risks of potential side effects of the powder formulations in the dispenser towards the vectoring insect. This study reports on the development of a laboratory miniature-dispenser-based bioassay. This bioassay system was used to investigate the compatibility of five model products, Prestop-Mix, Signum, kaolin, wheat flour and cellulose, with the bumblebee, Bombus terrestris L. The laboratory one-way miniature-dispenser bioassay showed that the fungicides and the carrier/diluent kaolin caused a worker mortality of > 70% after 5 weeks of exposure, while worker loss with wheat flour and cellulose was no higher than in the blank control (i.e. empty miniature dispenser) (dispenser bioassay comprised separated passageways and demonstrated that only kaolin was toxic (89 ± 11%). These results were also confirmed in a flight-cage experiment. In addition, a negative effect was observed against reproduction/colony development when nests were exposed to kaolin (P dispenser and flight-cage bioassays. In the context of entomovectoring technology, the developed laboratory two-way miniature-dispenser bioassay gives a reliable prediction of the hazards associated with powder products. Additionally, the present data indicate the possibility of using cellulose and kaolin as respective negative and positive control carriers/diluents in future risk assessment experiments. Overall, the results show that, apart from kaolin, the tested fungicides and carriers/diluents are safe to be used with B. terrestris. Copyright © 2011 Society of Chemical Industry.

  19. The Impact of Syrian Refugees on the Labor Market in Neighboring Countries: Empirical Evidence from Jordan

    OpenAIRE

    Fakih, Ali; Ibrahim, May

    2016-01-01

    This paper analyzes time-sensitive data on a humanitarian crisis in the Middle East. It aims to assess the impact of the steep influx of Syrian refugees into Jordan on the country's labor market since the onset of the conflict in Syria (March 2011). As of August 2014, nearly 3 million registered Syrians have sought refuge in neighboring countries (Lebanon, Jordan, Iraq, and Turkey), according to the United Nations High Commissioner for Refugees (UNHCR). Jordan and Lebanon are hosting the majo...

  20. FCNN-MR: A Parallel Instance Selection Method Based on Fast Condensed Nearest Neighbor Rule

    OpenAIRE

    Lu Si; Jie Yu; Shasha Li; Jun Ma; Lei Luo; Qingbo Wu; Yongqi Ma; Zhengji Liu

    2017-01-01

    Instance selection (IS) technique is used to reduce the data size to improve the performance of data mining methods. Recently, to process very large data set, several proposed methods divide the training set into some disjoint subsets and apply IS algorithms independently to each subset. In this paper, we analyze the limitation of these methods and give our viewpoint about how to divide and conquer in IS procedure. Then, based on fast condensed nearest neighbor (FCNN) rul...

  1. From sublexical facilitation to lexical competition: ERP effects of masked neighbor priming.

    Science.gov (United States)

    Meade, Gabriela; Grainger, Jonathan; Midgley, Katherine J; Emmorey, Karen; Holcomb, Phillip J

    2018-04-15

    Interactive-activation models posit that visual word recognition involves co-activation of orthographic neighbors (e.g., note, node) and competition among them via lateral inhibitory connections. Behavioral evidence of this lexical competition comes from masked priming paradigms, in which target words elicit slower responses when preceded by a neighbor (e.g., note-NODE) than when preceded by an unrelated word (e.g., kiss-NODE). In the present study, we used ERPs to investigate how masked high frequency word primes influence processing of low frequency word and pseudoword targets. Word targets preceded by a neighbor prime elicited larger negativities within the N400 window than those preceded by an unrelated prime across bilateral anterior sites, which we call a reversed N400 priming effect. Consistent with the behavioral literature, the size of the reversed N400 priming effect was larger for targets from high-density orthographic neighborhoods and for participants who scored higher on a behavioral measure of spelling recognition. Indeed, the opposite effect (i.e., smaller negativities within the N400 window for word targets preceded by a neighbor) was observed for words from low-density orthographic neighborhoods and for less-skilled spellers. Traditional priming was also observed within the N250 window for word targets and within both the N250 or N400 windows for pseudoword targets. The specificity of the reversed N400 priming effect to situations in which both words have precise lexical representations suggests that it, like the behavioral interference effect, indexes lexical competition during visual word recognition. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Investment Incentives and Effective Tax Rates in the Philippines; A Comparison With Neighboring Countries

    OpenAIRE

    Alexander D Klemm; Dennis P Botman; Reza Baqir

    2008-01-01

    We compare the general tax provisions and investment incentives in the Philippines to six other east-Asian economies-Malaysia, Indonesia, Lao, Vietnam, Cambodia, and Thailand. We calculate effective tax rates and find that general effective tax rates are relatively high in the Philippines, while investment incentives are comparable to those in neighboring countries. Tax holidays are most attractive for very profitable firms, creating redundancy, and for investment in short-lived assets. We al...

  3. High-performance thin-layer chromatography linked with (bio)assays and mass spectrometry - a suited method for discovery and quantification of bioactive components? Exemplarily shown for turmeric and milk thistle extracts.

    Science.gov (United States)

    Taha, Mahmoud N; Krawinkel, Michael B; Morlock, Gertrud E

    2015-05-15

    Extraction parameters, chemical fingerprint, and the single compounds' activity levels were considered for the selection of active botanicals. For an initial survey, the total bioactivity (i.e., total reducing capacity, total flavonoids contents and free radical scavenging capacity) of 21 aqueous and 21 ethanolic plant extracts was investigated. Ethanolic extracts showed a higher yield and were further analyzed by HPTLC in detail to obtain fingerprints of single flavonoids and further bioactive components. Exemplarily shown for turmeric (Curcuma longa) and milk thistle (Silybum marianum), effect-directed analysis (EDA) was performed using three selected (bio)assays, the Aliivibrio fischeri bioassay, the Bacillus subtilis bioassay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH*) assay. As a proof of principle, the bioactive components found in the extracts were confirmed by HPTLC-MS. Bioassays in combination with planar chromatography directly linked to the known, single effective compounds like curcumin and silibinin. However, also some unknown bioactive components were discovered and exemplarily characterized, which demonstrated the strength of this kind of EDA. HPTLC-UV/Vis/FLD-EDA-MS could become a useful tool for selection of active botanicals and for the activity profiling of the active ingredients therein. The flexibility in effect-directed detections allows a comprehensive survey of effective ingredients in samples. This streamlined methodology comprised a non-targeted, effect-directed screening first, followed by a highly targeted characterization of the discovered bioactive compounds. HPTLC-EDA-MS can also be recommended for bioactivity profiling of food on the food intake side, as not only effective phytochemicals, but also unknown bioactive degradation products during food processing or contamination products or residues or metabolites can be detected. Thus, an efficient survey on potential food intake effects on wellness could be obtained. Having performed

  4. A new approach to very short term wind speed prediction using k-nearest neighbor classification

    International Nuclear Information System (INIS)

    Yesilbudak, Mehmet; Sagiroglu, Seref; Colak, Ilhami

    2013-01-01

    Highlights: ► Wind speed parameter was predicted in an n-tupled inputs using k-NN classification. ► The effects of input parameters, nearest neighbors and distance metrics were analyzed. ► Many useful and reasonable inferences were uncovered using the developed model. - Abstract: Wind energy is an inexhaustible energy source and wind power production has been growing rapidly in recent years. However, wind power has a non-schedulable nature due to wind speed variations. Hence, wind speed prediction is an indispensable requirement for power system operators. This paper predicts wind speed parameter in an n-tupled inputs using k-nearest neighbor (k-NN) classification and analyzes the effects of input parameters, nearest neighbors and distance metrics on wind speed prediction. The k-NN classification model was developed using the object oriented programming techniques and includes Manhattan and Minkowski distance metrics except from Euclidean distance metric on the contrary of literature. The k-NN classification model which uses wind direction, air temperature, atmospheric pressure and relative humidity parameters in a 4-tupled space achieved the best wind speed prediction for k = 5 in the Manhattan distance metric. Differently, the k-NN classification model which uses wind direction, air temperature and atmospheric pressure parameters in a 3-tupled inputs gave the worst wind speed prediction for k = 1 in the Minkowski distance metric

  5. Distribution and epidemiologic trends of HBV genotypes and subtypes in 14 countries neighboring china.

    Science.gov (United States)

    Qian, Zhao; Jianqiong, Wang; Hongmei, Li; Rong, Zeng; Li, Li; Jinping, Zhang; Tao, Shen

    2015-05-01

    The number of cases of HBV infection reported by the WHO for each district and country is positively correlated with the number of HBV sequences in the database isolated from the corresponding district and country. This study determined distribution characteristics of HBV genotypes and subtypes in 14 countries neighboring China. The progress made in genomic research involving HBV was also reviewed. Nine hundred fifty-one complete genome sequences of HBV from 14 countries neighboring China were selected from NCBI. The sequence-related information was analyzed and recorded. One hundred seventy-two sequences of HBV genotype B were screened for alignment using DNA star and MEGA 5.1. Dominant HBV genotypes in the countries neighboring China were genotypes B, C and D and dominant subtypes were adw2 and adrq+. The association between genotype and serotype of HBV in these countries was shown to differ from previous research results. As shown by sequence alignment, the sequence divergence between five subgenotypes (B3, B5, B7, B8 and B9) was below 4%. The B subgenotypes shared six common specific amino acid sites in the S region. The B3, B5, B7, B8 and B9 subgenotypes can be clustered into quasi-sub-genotype B3 and the open reading frame of HBV has a start codon preference; however, whether a mutation in the start codon in the pre-S2 region has an impact on survival and replication of HBV remains to be determined.

  6. Gap junctions are essential for generating the correlated spike activity of neighboring retinal ganglion cells.

    Directory of Open Access Journals (Sweden)

    Béla Völgyi

    Full Text Available Neurons throughout the brain show spike activity that is temporally correlated to that expressed by their neighbors, yet the generating mechanism(s remains unclear. In the retina, ganglion cells (GCs show robust, concerted spiking that shapes the information transmitted to central targets. Here we report the synaptic circuits responsible for generating the different types of concerted spiking of GC neighbors in the mouse retina. The most precise concerted spiking was generated by reciprocal electrical coupling of GC neighbors via gap junctions, whereas indirect electrical coupling to a common cohort of amacrine cells generated the correlated activity with medium precision. In contrast, the correlated spiking with the lowest temporal precision was produced by shared synaptic inputs carrying photoreceptor noise. Overall, our results demonstrate that different synaptic circuits generate the discrete types of GC correlated activity. Moreover, our findings expand our understanding of the roles of gap junctions in the retina, showing that they are essential for generating all forms of concerted GC activity transmitted to central brain targets.

  7. A Novel AMR-WB Speech Steganography Based on Diameter-Neighbor Codebook Partition

    Directory of Open Access Journals (Sweden)

    Junhui He

    2018-01-01

    Full Text Available Steganography is a means of covert communication without revealing the occurrence and the real purpose of communication. The adaptive multirate wideband (AMR-WB is a widely adapted format in mobile handsets and is also the recommended speech codec for VoLTE. In this paper, a novel AMR-WB speech steganography is proposed based on diameter-neighbor codebook partition algorithm. Different embedding capacity may be achieved by adjusting the iterative parameters during codebook division. The experimental results prove that the presented AMR-WB steganography may provide higher and flexible embedding capacity without inducing perceptible distortion compared with the state-of-the-art methods. With 48 iterations of cluster merging, twice the embedding capacity of complementary-neighbor-vertices-based embedding method may be obtained with a decrease of only around 2% in speech quality and much the same undetectability. Moreover, both the quality of stego speech and the security regarding statistical steganalysis are better than the recent speech steganography based on neighbor-index-division codebook partition.

  8. Elementary excitations and thermodynamics of zig-zag spin ladders with alternating nearest neighbor exchange interactions

    International Nuclear Information System (INIS)

    Zvyagin, A.A.; Cheranovskii, V.O.

    2009-01-01

    A one-dimensional spin-1/2 model in which the alternation of the exchange interactions between neighboring spins is accompanied by the next-nearest-neighbor (NNN) spin exchange (zig-zag spin ladder with alternation) is studied. The thermodynamic characteristics of the model quantum spin chain are obtained in the mean-field-like approximation. Depending on the strength of the NNN interactions, the model manifests either the spin-gapped behavior of low-lying excitations at low magnetic fields, or ferrimagnetic ordering in the ground state with gapless low-lying excitations. The system undergoes second-order or first-order quantum phase transitions, governed by the external magnetic field, NNN coupling strength, and the degree of the alternation. Hence, NNN spin-spin interactions in a dimerized quantum spin chain can produce a spontaneous magnetization. On the other hand, for quantum spin chains with a spontaneous magnetization, caused by NNN spin-spin couplings, the alternation of nearest-neighbor (NN) exchange interactions can cause destruction of that magnetization and the onset of a spin gap for low-lying excitations. Alternating NN interactions produce a spin gap between two branches of low-energy excitations, and the NNN interactions yield asymmetry of the dispersion laws of those excitations, with possible minima corresponding to incommensurate structures in the spin chain

  9. Improving the accuracy of k-nearest neighbor using local mean based and distance weight

    Science.gov (United States)

    Syaliman, K. U.; Nababan, E. B.; Sitompul, O. S.

    2018-03-01

    In k-nearest neighbor (kNN), the determination of classes for new data is normally performed by a simple majority vote system, which may ignore the similarities among data, as well as allowing the occurrence of a double majority class that can lead to misclassification. In this research, we propose an approach to resolve the majority vote issues by calculating the distance weight using a combination of local mean based k-nearest neighbor (LMKNN) and distance weight k-nearest neighbor (DWKNN). The accuracy of results is compared to the accuracy acquired from the original k-NN method using several datasets from the UCI Machine Learning repository, Kaggle and Keel, such as ionosphare, iris, voice genre, lower back pain, and thyroid. In addition, the proposed method is also tested using real data from a public senior high school in city of Tualang, Indonesia. Results shows that the combination of LMKNN and DWKNN was able to increase the classification accuracy of kNN, whereby the average accuracy on test data is 2.45% with the highest increase in accuracy of 3.71% occurring on the lower back pain symptoms dataset. For the real data, the increase in accuracy is obtained as high as 5.16%.

  10. Resampling nucleotide sequences with closest-neighbor trimming and its comparison to other methods.

    Directory of Open Access Journals (Sweden)

    Kouki Yonezawa

    Full Text Available A large number of nucleotide sequences of various pathogens are available in public databases. The growth of the datasets has resulted in an enormous increase in computational costs. Moreover, due to differences in surveillance activities, the number of sequences found in databases varies from one country to another and from year to year. Therefore, it is important to study resampling methods to reduce the sampling bias. A novel algorithm-called the closest-neighbor trimming method-that resamples a given number of sequences from a large nucleotide sequence dataset was proposed. The performance of the proposed algorithm was compared with other algorithms by using the nucleotide sequences of human H3N2 influenza viruses. We compared the closest-neighbor trimming method with the naive hierarchical clustering algorithm and [Formula: see text]-medoids clustering algorithm. Genetic information accumulated in public databases contains sampling bias. The closest-neighbor trimming method can thin out densely sampled sequences from a given dataset. Since nucleotide sequences are among the most widely used materials for life sciences, we anticipate that our algorithm to various datasets will result in reducing sampling bias.

  11. Classification of EEG Signals using adaptive weighted distance nearest neighbor algorithm

    Directory of Open Access Journals (Sweden)

    E. Parvinnia

    2014-01-01

    Full Text Available Electroencephalogram (EEG signals are often used to diagnose diseases such as seizure, alzheimer, and schizophrenia. One main problem with the recorded EEG samples is that they are not equally reliable due to the artifacts at the time of recording. EEG signal classification algorithms should have a mechanism to handle this issue. It seems that using adaptive classifiers can be useful for the biological signals such as EEG. In this paper, a general adaptive method named weighted distance nearest neighbor (WDNN is applied for EEG signal classification to tackle this problem. This classification algorithm assigns a weight to each training sample to control its influence in classifying test samples. The weights of training samples are used to find the nearest neighbor of an input query pattern. To assess the performance of this scheme, EEG signals of thirteen schizophrenic patients and eighteen normal subjects are analyzed for the classification of these two groups. Several features including, fractal dimension, band power and autoregressive (AR model are extracted from EEG signals. The classification results are evaluated using Leave one (subject out cross validation for reliable estimation. The results indicate that combination of WDNN and selected features can significantly outperform the basic nearest-neighbor and the other methods proposed in the past for the classification of these two groups. Therefore, this method can be a complementary tool for specialists to distinguish schizophrenia disorder.

  12. Bioassay of circulating luteinizing hormone in the rhesus monkey: comparison with radioimmunoassay during physiological changes

    International Nuclear Information System (INIS)

    Dufau, M.L.; Hodgen, G.D.; Goodman, A.L.; Catt, K.J.

    1977-01-01

    The concentration of biologically active LH in Rhesus monkey (Macaca mulatta) serum was measured by a highly sensitive bioassay based upon testosterone production by dispersed rat interstitial cells. The sensitivity of the in vitro bioassay was equal to or higher than that of radioimmunoassay, with detection limits of 0.1 mIU of human menopausal gonadotropin (hMG) or 10 ng of a Rhesus pituitary gonadotropin preparation (LER-1909-2). Parallel dose-response curves were obtained for hMG and Rhesus monkey pituitary gonadotropin. The method permits bioassay of LH in 20--100 μl of serum from adult male monkeys, and from female monkeys during the follicular and luteal phases of the menstrual cycle. Bioactive LH concentrations could be assayed in 0.25 to 5 μl of serum from mid-cycle, postmenopausal, and castrated female monkeys. Serum LH was undetectable in two hypophysectomized adult female monkeys and six intact immature animals, and was 13 +- 6 (SD) mIU/ml in adult male monkeys. In adult females, follicular phase LH levels ranged from 17 to 169 mIU/ml, with a mean of 76 +- 52 mIU/ml. The midcycle LH peak was 1738 +- 742 mIU/ml and the luteal phase values ranged from 6-47 mIU/ml, with a mean of 35 +- 5 mIU/ml. Serum LH concentrations ranged from 100 to 900 mIU/ml in two menopausal females, and from 590--1480 mIU/ml in castrated females. Treatment of castrated female monkeys with estrogen plus progesterone produced an initial two-fold rise in sepum LH within 3 days, followed by a gradual decline to one-fourth to one-tenth of the initial levels after 10 days of treatment. Serum LH was suppressed to undetectable levels during the third week, and remained so for the duration of the 60-day treatment period

  13. Guidance document for prepermit bioassay testing of low-level radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.L.; Harrison, F.L.

    1990-11-01

    In response to the mandate of Public Law 92-532, the Marine Protection, Research, and Sanctuaries Act (MPRSA) of 1972, as amended, the Environmental Protection Agency (EPA) has developed a program to promulgate regulations and criteria to control the ocean disposal of radioactive wastes. The EPA seeks to understand the mechanisms for biological response of marine organisms to the low levels of radioactivity that may arise from the release of these wastes as a result of ocean-disposal practices. Such information will play an important role in determining the adequacy of environmental assessments provided to the EPA in support of any disposal permit application. Although the EPA requires packaging of low-level radioactive waste to prevent release during radiodecay of the materials, some release of radioactive material into the deep-sea environment may occur when a package deteriorates. Therefore, methods for evaluating the impact on biota are being evaluated. Mortality and phenotypic responses are not anticipated at the expected low environmental levels that might occur if radioactive materials were released from the low-level waste packages. Therefore, traditional bioassay systems are unsuitable for assessing sublethal effects on biota in the marine environment. The EPA Office of Radiation Programs (ORP) has had an ongoing program to examine sublethal responses to radiation at the cellular level, using cytogenetic end points. This technical guidance report represents prepermit bioassay procedures that potentially may be applicable to the assessment of effects from a mixture of radionuclides that could be released from a point source at the ocean bottom. Methodologies along with rationale and a discussion of uncertainty are presented for the sediment benthic bioassay protocols identified in this report.

  14. A novel method for standardized application of fungal spore coatings for mosquito exposure bioassays.

    Science.gov (United States)

    Farenhorst, Marit; Knols, Bart G J

    2010-01-20

    Interest in the use of fungal entomopathogens against malaria vectors is growing. Fungal spores infect insects via the cuticle and can be applied directly on the insect to evaluate infectivity. For flying insects such as mosquitoes, however, application of fungal suspensions on resting surfaces is more realistic and representative of field settings. For this type of exposure, it is essential to apply specific amounts of fungal spores homogeneously over a surface for testing the effects of fungal dose and exposure time. Contemporary methods such as spraying or brushing spore suspensions onto substrates do not produce the uniformity and consistency that standardized laboratory assays require. Two novel fungus application methods using equipment developed in the paint industry are presented and compared. Wired, stainless steel K-bars were tested and optimized for coating fungal spore suspensions onto paper substrates. Different solvents and substrates were evaluated. Two types of coating techniques were compared, i.e. manual and automated coating. A standardized bioassay set-up was designed for testing coated spores against malaria mosquitoes. K-bar coating provided consistent applications of spore layers onto paper substrates. Viscous Ondina oil formulations were not suitable and significantly reduced spore infectivity. Evaporative Shellsol T solvent dried quickly and resulted in high spore infectivity to mosquitoes. Smooth proofing papers were the most effective substrate and showed higher infectivity than cardboard substrates. Manually and mechanically applied spore coatings showed similar and reproducible effects on mosquito survival. The standardized mosquito exposure bioassay was effective and consistent in measuring effects of fungal dose and exposure time. K-bar coating is a simple and consistent method for applying fungal spore suspensions onto paper substrates and can produce coating layers with accurate effective spore concentrations. The mosquito bioassay

  15. A novel method for standardized application of fungal spore coatings for mosquito exposure bioassays

    Directory of Open Access Journals (Sweden)

    Knols Bart GJ

    2010-01-01

    Full Text Available Abstract Background Interest in the use of fungal entomopathogens against malaria vectors is growing. Fungal spores infect insects via the cuticle and can be applied directly on the insect to evaluate infectivity. For flying insects such as mosquitoes, however, application of fungal suspensions on resting surfaces is more realistic and representative of field settings. For this type of exposure, it is essential to apply specific amounts of fungal spores homogeneously over a surface for testing the effects of fungal dose and exposure time. Contemporary methods such as spraying or brushing spore suspensions onto substrates do not produce the uniformity and consistency that standardized laboratory assays require. Two novel fungus application methods using equipment developed in the paint industry are presented and compared. Methods Wired, stainless steel K-bars were tested and optimized for coating fungal spore suspensions onto paper substrates. Different solvents and substrates were evaluated. Two types of coating techniques were compared, i.e. manual and automated coating. A standardized bioassay set-up was designed for testing coated spores against malaria mosquitoes. Results K-bar coating provided consistent applications of spore layers onto paper substrates. Viscous Ondina oil formulations were not suitable and significantly reduced spore infectivity. Evaporative Shellsol T solvent dried quickly and resulted in high spore infectivity to mosquitoes. Smooth proofing papers were the most effective substrate and showed higher infectivity than cardboard substrates. Manually and mechanically applied spore coatings showed similar and reproducible effects on mosquito survival. The standardized mosquito exposure bioassay was effective and consistent in measuring effects of fungal dose and exposure time. Conclusions K-bar coating is a simple and consistent method for applying fungal spore suspensions onto paper substrates and can produce coating layers

  16. Using a macroalgal δ15N bioassay to detect cruise ship waste water effluent inputs

    International Nuclear Information System (INIS)

    Kaldy, James

    2011-01-01

    Highlights: → Green macroalgae exposed to nutrient solutions exhibited changes in tissue 15 N signatures. → Macroalgae exhibited no fractionation with NO 3 and slight fractionation with NH 4 . → Algae exposed to cruise ship waste water had increased tissue δ 15 N indicating a heavy N source. → Field bioassays exhibited decreased δ 15 N indicating isotopically light riverine δ 15 N-NO 3 was likely the dominant N source. → Algal bioassays could not detect a δ 15 N cruise ship waste water signal in this system. - Abstract: Green macroalgae bioassays were used to determine if the δ 15 N signature of cruise ship waste water effluent (CSWWE) could be detected in a small harbor. Opportunistic green macroalgae (Ulva spp.) were collected, cultured under nutrient depleted conditions and characterized with regard to N content and δ 15 N. Samples of algae were used in controlled incubations to evaluate the direction of isotope shift from exposure to CSWWE. Algae samples exposed to CSWWE exhibited an increase of 1-2.5 per mille in δ 15 N values indicating that the CSWWE had an enriched isotope signature. In contrast, algae samples exposed to field conditions exhibited a significant decrease in the observed δ 15 N indicating that a light N source was used. Isotopically light, riverine nitrogen derived from N 2 -fixing trees in the watershed may be a N source utilized by algae. These experiments indicate that the δ 15 N CSWWE signature was not detectable under the CSWWE loading conditions of this experiment.

  17. Guidance document for prepermit bioassay testing of low-level radioactive waste

    International Nuclear Information System (INIS)

    Anderson, S.L.; Harrison, F.L.

    1990-11-01

    In response to the mandate of Public Law 92-532, the Marine Protection, Research, and Sanctuaries Act (MPRSA) of 1972, as amended, the Environmental Protection Agency (EPA) has developed a program to promulgate regulations and criteria to control the ocean disposal of radioactive wastes. The EPA seeks to understand the mechanisms for biological response of marine organisms to the low levels of radioactivity that may arise from the release of these wastes as a result of ocean-disposal practices. Such information will play an important role in determining the adequacy of environmental assessments provided to the EPA in support of any disposal permit application. Although the EPA requires packaging of low-level radioactive waste to prevent release during radiodecay of the materials, some release of radioactive material into the deep-sea environment may occur when a package deteriorates. Therefore, methods for evaluating the impact on biota are being evaluated. Mortality and phenotypic responses are not anticipated at the expected low environmental levels that might occur if radioactive materials were released from the low-level waste packages. Therefore, traditional bioassay systems are unsuitable for assessing sublethal effects on biota in the marine environment. The EPA Office of Radiation Programs (ORP) has had an ongoing program to examine sublethal responses to radiation at the cellular level, using cytogenetic end points. This technical guidance report represents prepermit bioassay procedures that potentially may be applicable to the assessment of effects from a mixture of radionuclides that could be released from a point source at the ocean bottom. Methodologies along with rationale and a discussion of uncertainty are presented for the sediment benthic bioassay protocols identified in this report

  18. Evaluation of internal exposure of nuclear medicine staff through in vivo and in vitro bioassay techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lucena, E.A.; Araujo, F.; Sousa, W.O.; Dantas, A.L.A.; Dantas, B.M. [Instituto de Radioprotecao e Dosimetria, CNEN, Av. Salvador Allende s/n, CEP 22780-160 Rio de Janeiro (Brazil); Rebelo, A.M.O.; Corbo, R. [Hospital Universitario Clementino Fraga Filho, HU-UFRJ, Av. Brigadeiro Trompowsky, s/n, ILHA do Fundao, CEP 21945-560, Rio de Janeiro, RJ (Brazil)

    2007-07-01

    The manipulation of a wide variety of unsealed sources in Nuclear Medicine results in a significant risk of internal exposure of the workers. {sup 131}I should be highlighted among the most frequently used radionuclides because of its large application for diagnosis and therapy of thyroid diseases. The increasing use of radionuclides for medical purposes creates a demand for feasible methodologies to perform occupational control of internal contamination. Currently in Brazil, there are {approx}300 nuclear medicine centres in operation but individual monitoring is still restricted to the control of external exposure. This work presents the development of in vivo and in vitro bioassay techniques aimed to quantify incorporation of radionuclides used in Nuclear Medicine. It is also presented the results of a preliminary survey of internal exposure of a group of workers involved in the preparation of therapeutic doses of {sup 131}I. Workers were monitored with a gamma camera available in the Nuclear Medicine Service of the University Hospital of Rio de Janeiro and at the Institute of Radiation Protection and Dosimetry Whole-Body Counter (IRDWBC). The in vivo detection systems were calibrated with a neck-thyroid phantom developed in IRD. Urine samples from radiopharmacy workers were collected after preparation and administration of therapeutic doses (10-250 mCi) of {sup 131}I and measured with a HPGe detection system available in the Bioassay Laboratory of IRD. The results show that the bioassay methods developed in this work present enough sensitivity for routine monitoring of nuclear medicine workers. All workers monitored in this survey presented positive results for {sup 131}I in urine samples and two workers presented detectable activities in thyroid when measured at the IRD-WBC. The highest committed effective dose per preparation was estimated to be 17 {mu}Sv. (authors)

  19. Bioassay requirements for 125I and 131I in medical, teaching and research institutions

    International Nuclear Information System (INIS)

    1983-09-01

    The more widespread use of radioactive isotopes of iodine (collectively referred to as radioiodines) as a research tool, coupled with their diagnostic and therapeutic uses in nuclear medicine, has resulted in an increased number of personnel who are exposed to these radioisotopes and who therefore should be monitored for internal radioiodine contamination. This document describes the minimum acceptable features of a bioassay programme which the Atomic Energy Control Board (AECB) requires to be available in institutions holding a prescribed substance licence authorising the use of significant quantities of 125 I or 131 I or both. A licensee may submit details of his own proposed bioassay programme to the AECB for approval. If such a programme fails to be approved, the programme described below shall be adhered to. This document does not deal with individuals who are likely to maintain a significant chronic thyroid burden of radioiodine. It is assumed that the radioiodine taken into the body is in a soluble, inorganic form (I 2 , iodide or iodate) or in an organic form (e.g. methyl iodide) which is metabolised in the body with a resultant release of iodide. Radioiodinated organic compounds which are not catabolised to iodide in the body to any significant degree are not the subject of this document, since the metabolism of the radioiodine will be dictated by the metabolism of the compound. This means that individuals whose only exposure to radioiodine is in the form of prepared radioiodinated compounds such as antigens and antibodies (e.g. individuals using radio immuno assay kits in which the antigen or antibody is supplied as radioiodinated material) are not required to participate in this bioassay programme for radioiodine

  20. GHSI emergency radionuclide bioassay laboratory network - summary of the second exercise

    International Nuclear Information System (INIS)

    Li, Chunsheng; Ko, Raymond; Quayle, Debora; Sadi, Baki; Bartizel, Christine; Battisti, Paolo; Boettger, Axel; Bouvier, Celine; Paquet, Francois; CapoteCuellar, Antonio; Carr, Zhanat; Hammond, Derek; Hartmann, Martina; Heikkinen, Tarja; Jones, Robert L.; Kim, Eunjoo; Koga, Roberto; Kukhta, Boris; Mitchell, Lorna; Morhard, Ryan; Rulik, Petr; Sergei, Aleksanin; Sierra, Inmaculada; Oliveira Sousa, Wandersonde; Szabo, Gyula

    2017-01-01

    The Global Health Security Initiative (GHSI) established a laboratory network within the GHSI community to develop collective surge capacity for radionuclide bioassay in response to a radiological or nuclear emergency as a means of enhancing response capability, health outcomes and community resilience. GHSI partners conducted an exercise in collaboration with the WHO Radiation Emergency Medical Preparedness and Assistance Network and the IAEA Response and Assistance Network, to test the participating laboratories (18) for their capabilities in in vitro assay of biological samples, using a urine sample spiked with multiple high-risk radionuclides ( 90 Sr, 106 Ru, 137 Cs, and 239 Pu). Laboratories were required to submit their reports within 72 h following receipt of the sample, using a pre-formatted template, on the procedures, methods and techniques used to identify and quantify the radionuclides in the sample, as well as the bioassay results with a 95% confidence interval. All of the participating laboratories identified and measured all or some of the radionuclides in the sample. However, gaps were identified in both the procedures used to assay multiple radionuclides in one sample, as well as in the methods or techniques used to assay specific radionuclides in urine. Two-third of the participating laboratories had difficulties in determining all the radionuclides in the sample. Results from this exercise indicate that challenges remain with respect to ensuring that results are delivered in a timely, consistent and reliable manner to support medical interventions. Laboratories within the networks are encouraged to work together to develop and maintain collective capabilities and capacity for emergency bioassay, which is an important component of radiation emergency response. (authors)

  1. Phytochemical, antimicrobial, insecticidal and brine shrimp lethality bioassay of the crude methanolic extract of Ajuga parviflora Benth.

    Science.gov (United States)

    Rahman, Najmur; Ahmad, Mansoor; Riaz, Muhammad; Mehjabeen; Jahan, Noor; Ahmad, Rizwan

    2013-07-01

    Methanolic extract of medicinal herb Ajuga parviflora Benth. was evaluated for phytochemical screening (the plant extract showed the presence of aromatic compounds, carbohydrates, glycosides, tannins, alkaloids, polyphenols, quinines and dions, aminophenols, steroids/sterols, flavonoids and terpenoids), antimicrobial activities against various strains of bacteria and fungi by using disc diffusion method and insecticidal activities against red flour beetle (Tribolium castaneum), wheat weevil (Sitophilis granaries) and their larvae. The crude extract showed anti-bacterial activity against all strains with a maximum zone of inhibition of 12mm diameter against Citrobacter and Pseudomonas aurogenosa. Standard drugs Ampicillin, Gentamicin and Amoxicillin were used in parallel. The crude extract did not show antifungal activity against the tested strains of fungi even at high doses. The crude methanolic extract was also used for insecticidal activity against the two types of insects and their larva. The extract showed no significant mortality in the tested strains. For brine shrimp lethality bioassay different concentrations 10, 100 and 1000ug/ml of the medicinal herb A. parviflora methanolic extract were used. After 24 hrs the percent mortality and LD50 value was calculated through probit analysis. The LD50 value of extract was 321.42μg/mL while that of standard drug cyclophosphamide was 16.09ug/ml.

  2. Presence of estrogenic activity from emission of fossil fuel combustion as detected by a recombinant yeast bioassay

    Science.gov (United States)

    Wang, Jingxian; Wu, Wenzhong; Henkelmann, Bernhard; You, Li; Kettrup, Antonius; Schramm, Karl-Werner

    Estrogenic activities of emission samples generated by fossil fuel combustion were investigated with human estrogen receptor (ER) recombinant yeast bioassay. The results showed that there were weak but clear estrogenic activities in combustion emissions of fossil fuels including coal, petroleum, and diesel. The estrogenic relative potency (RP) of fossil fuel combustion was the highest in petroleum-fired car, followed by coal-fired stove, diesel-fired agrimotor, coal-fired electric power station. On the other hand, the estrogenic relative inductive efficiency (RIE) was the highest in coal-fired stove and coal-fired electric power station, followed by petroleum-fired car and diesel-fired agrimotor. The estrogenic activities in the sub-fractions from chromatographic separation of emitted materials were also determined. The results indicated that different chemical fractions in these complex systems have different estrogenic potencies. The GC/MS analysis of the emission showed that there were many aromatic carbonyls, big molecular alcohol, PAHs and derivatives, and substituted phenolic compounds and derivatives which have been reported as environmental estrogens. The existence of estrogenic substances in fossil fuel combustion demands further investigation of their potential adverse effects on human and on the ecosystem. The magnitude of pollution due to global usage of fossil fuels makes it imperative to understand the issue of fossil fuel-derived endocrine activities and the associated health risks, particularly the aggregated risks stemmed from exposure to toxicants of multiple sources.

  3. Use of plant genotoxicity bioassay for the evaluation of efficiency of algal biofilters in bioremediation of toxic industrial effluent.

    Science.gov (United States)

    Abdel Migid, Hala M; Azab, Yehia A; Ibrahim, Waeel M

    2007-01-01

    The toxicity and efficacy of an algal-based bioremediation technology were assessed through bioassays for ecological risk of contaminated industrial effluents. The algal bioremoval of heavy metals was evaluated using an in vitro approach. Phytogenotoxicity tests were conducted with Allium cepa and Vicia faba plants to evaluate the genotoxicity of the industrial effluents before and after treatment with different kinds of algal biofilters (BF). Root cells were exposed for 24 h to different dilutions of both raw and treated effluent of a chemical fertilizer factory. Three cytogenetic endpoints were used to assess the mutagenic potencies of the industrial effluent: mitotic inhibition, mitotic chromosome aberrations, and nuclear irregularities in interphase cells. Before algal treatment, the industrial effluent caused strong genotoxic effects represented by severe inhibition in mitotic activity of meristematic cells and high frequency of both chromosome and nucleus abnormalities. After algal treatment, the cytotoxic effects of 30% and 60% concentrations of the treated effluent were comparable to those of 5% and 10% concentrations before treatment, respectively, and the frequency of both chromosome and nuclear abnormalities declined by approximately 50%. Statistical analysis of the data indicates a significant reduction in genotoxicity associated with a remarkable reduction in heavy metal concentrations after bioremediation by algal BF. The Allium and Vicia genotoxicity approach was effective in monitoring bioremediated effluent for toxicity.

  4. A ferricyanide-mediated activated sludge bioassay for fast determination of the biochemical oxygen demand of wastewaters.

    Science.gov (United States)

    Jordan, Mark A; Welsh, David T; Teasdale, Peter R; Catterall, Kylie; John, Richard

    2010-12-01

    Activated sludge was successfully incorporated as the biocatalyst in the fast, ferricyanide-mediated biochemical oxygen demand (FM-BOD) bioassay. Sludge preparation procedures were optimized for three potential biocatalysts; aeration basin mixed liquor, aerobic digester sludge and return activated sludge. Following a 24h starving period, the return activated sludge and mixed liquor sludges reported the highest oxidative degradation of a standard glucose/glutamic acid (GGA) mixture and the return activated sludge also recorded the lowest endogenous FM-respiration rate. Dynamic working ranges up to 170 mg BOD(5)L(-1) for OECD standard solutions and 300mg BOD(5)L(-1) for GGA were obtained. This is a considerable improvement upon the BOD(5) standard assay and most other rapid BOD techniques. Time-series ferricyanide-mediated oxidation of the OECD(170) standard approached that of the GGA(198) standard after 3-6h. This is noteworthy given the OECD standard is formulated as a synthetic sewage analogue. A highly significant correlation with the BOD(5) standard method (n=35, p<0.001, R=0.952) was observed for a wide diversity of real wastewater samples. The mean degradation efficiency was indistinguishable from that observed for the BOD(5) assay. These results demonstrate that the activated sludge FM-BOD assay may be used for simple, same-day BOD analysis of wastewaters. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Detection of endocrine active substances in the aquatic environment in southern Taiwan using bioassays and LC-MS/MS.

    Science.gov (United States)

    Chen, Kuang-Yu; Chou, Pei-Hsin

    2016-06-01

    Endocrine active substances, including naturally occurring hormones and various synthetic chemicals have received much concern owing to their endocrine disrupting potencies. It is essential to monitor their environmental occurrence since these compounds may pose potential threats to biota and human health. In this study, yeast-based reporter assays were carried out to investigate the presence of (anti-)androgenic, (anti-)estrogenic, and (anti-)thyroid compounds in the aquatic environment in southern Taiwan. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was also used to measure the environmental concentrations of selected endocrine active substances for assessing potential ecological risks and characterizing contributions to the endocrine disrupting activities. Bioassay results showed that anti-androgenic (ND-7489 μg L(-1) flutamide equivalent), estrogenic (ND-347 ng L(-1) 17β-estradiol equivalent), and anti-thyroid activities were detected in the dissolved and particulate phases of river water samples, while anti-estrogenic activities (ND-10 μg L(-1) 4-hydroxytamoxifen equivalent) were less often found. LC-MS/MS analysis revealed that anti-androgenic and estrogenic contaminants, such as bisphenol A, triclosan, and estrone were frequently detected in Taiwanese rivers. In addition, their risk quotient values were often higher than 1, suggesting that they may pose an ecological risk to the aquatic biota. Further identification of unknown anti-androgenic and estrogenic contaminants in Taiwanese rivers may be necessary to protect Taiwan's aquatic environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Molecular structure of Mycobacterium tuberculosis population in Russia and its interaction with neighboring countries.

    Science.gov (United States)

    Mokrousov, I

    2015-03-01

    The tuberculosis (TB) situation in Russia is aggravated by the emergence and the spread of multidrug-resistant strains, HIV co-infection and drawbacks in the health control system. The Mycobacterium tuberculosis population structure in Russia has been defined by the remarkable mass migration in the 20th century, the variable genetic background of different ethnic groups inhabiting Russia, and by the pathobiology of circulating strains. Here, I will review the phylogeography and pathobiology of: (i) the dominating Beijing family; (ii) the Latin-American Mediterranean (LAM) family, the second largest in Russia and MDR-associated in some regions; and (iii) the Ural family, endemic in Russia and thought to be less transmissible and drug resistant. M. tuberculosis variant Beijing В0/W148 is regarded as a successful clone of M. tuberculosis widespread in the former Soviet Union. However, a closer look reveals a peculiar clinal gradient of its geographic distribution; it peaks in Siberia and, to a lesser extent, in the European part of the former USSR. In contrast, its rate is sharply decreased in the Asian part of the former Soviet Union, and it is absent in the autochthonous populations elsewhere in the world. Two interdependent hypotheses will be put forward. First, B0/W148 likely originated in Siberia and its primary dispersal was driven by a massive population outflow from Siberia to European Russia in the period 1960-1980. Second, a historically recent phylogenetically demonstrated successful dissemination of the Beijing B0/W148 strain was triggered by an advent and wide use of the modern anti-TB drugs and was due to its remarkable capacity to acquire drug resistance. Robust phylogenetic markers were used to study the evolution of LAM and its major sublineages in Russia and its neighboring countries. A total of 250 M. tuberculosis isolates were assigned to LAM based on analysis of LAM-specific SNP in Rv3062 and Rv0129c. The family status was rectified for 121

  7. Toxicity of Single and Mixed Contaminants in Seawater Measured with Acute Toxicity Bioassays

    Directory of Open Access Journals (Sweden)

    A.R. Fernandez-Alba

    2002-01-01

    Full Text Available Different types of organic pollutants commonly detected in seawater have been evaluated by acute toxicity bioassays. Vibrio fischeri, Daphnia magna, and Selenastrum capricornotum were selected to test toxic effects of individual compounds and mixtures of these compounds, obtaining EC50 values in the range of 0.001 to 28.9 mg/l. In the case of mixtures, synergistic toxic responses were seen for a clear majority of the cases (>60%. Mixtures containing methyl-tertiary-butyl ether (MTBE exhibit accelerated processes that result in a change in concentration required to produce a toxic effect; for example, in the case of mixtures containing MTBE and Diuron and Dichlofluanid.

  8. Sensitive bioassay for detection of PPAR{alpha} potentially hazardous ligands with gold nanoparticle probe

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Wei; Wan, Yan-Jian [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China); Wang, Xianliang [Division of Environmental Pollution and Human Health, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Li, Yuan-yuan; Yang, Wen-Jie; Wang, Chun-Xiang [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China); Xu, Shun-qing, E-mail: shunqing@mails.tjmu.edu.cn [Minister of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei Province 430030 (China)

    2011-09-15

    Highlights: {yields} We develop a sensitive and high throughput method to screen PPAR{alpha} ligands. {yields} This method is based on the ligand-receptor interaction on microplate. {yields} The sensitivity is increased through sliver enhancement on captured gold nanoparticle probes. {yields} There is a significant correlation between the bioassay and LC-MS for water spiked samples. - Abstract: There are so many kinds of peroxisome proliferator-activated receptor {alpha} (PPAR{alpha}) ligands with hazardous effect for human health in the environment, such as certain herbicides, plasticizers and drugs. Among these agonists, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and mono-(2-ethylhexyl) phthalate (MEHP) are mostly investigated due to their persistence and accumulation in environment and their potential toxicity via PPAR{alpha}. This investigation aims at developing a bioassay method to detect PPAR{alpha} ligands based on the ligand-receptor interaction on microplate. PPAR{alpha}, which formed heterodimers with retinoid X receptor-{alpha} (RXR{alpha}), were activated by PPAR{alpha} ligands to form ligands-PPAR{alpha}-RXR{alpha} complexes. Then the complexes were transferred into a microplate and captured via monoclonal anti-PPAR{alpha} antibody. The PPAR{alpha} responsive elements (PPRE) modified-gold nanoparticle probes were captured by the ligand-PPAR{alpha}-RXR{alpha} complexes immobilized on the microplate, and then could be quantified through measuring the optical density after silver enhancement. The results showed that PFOS was quantified with a linear range from 100 pM to 1 {mu}M and the detection limit was 10 pM. In addition to PFOS, PFOA and MEHP were also quantified within a proper range through the proposed bioassay. This bioassay was compared with that of liquid chromatography tandem-mass spectrometry (LC-MS) for water spiked samples with a significant correlation (r = 0.9893). This study provides a high-throughput detection

  9. Gamma radiation and ems treatment of black cumin cultivars for mutational bioassays

    International Nuclear Information System (INIS)

    Mitra, P.K.; Bhowmik, G.

    1997-01-01

    Ten different types of chlorophyll mutations were induced in two cultivars of black cumin (Nigella sativa L.) after gamma irradiation and EMS treatment. Mutation frequency was proportional to dose for gamma rays, but not for EMS. Higher doses of gamma rays and lower concentration/duration of EMS were most efficient. Difference in the response of both cultivars due to mutagenic treatment indicate variation in the genetic architecture of the two cultivars. Origin and use of black cumin cultivars for mutagen bioassays studies are discussed

  10. FIRST RESULTS ON THE DIRECTION STATISTICS OF PAIRS OF EPICENTERS OF NEIGHBOR EARTHQUAKES ON KAMCHATKA

    Directory of Open Access Journals (Sweden)

    A. A. Gusev

    2016-01-01

    -diagrams are counted off from the direction with azimuth of 37° that represents the strike of the island arc. Before constructing rose diagrams, the modified azimuths were reduced to the [0° 180°] range by subtracting 180° when needed. One can see that with the stricter limit of 0.5 days, histograms and rose diagrams show more expressed deviations from the uniform (isotropic distribution of angles. For both variants of the maximum delay, the along-arc oriented pairs manifest themselves (at n about 0° and 180°. At the less strict limit of 5 days, this orientation begins to dominate. Although this tendency formally means a break of isotropy, it is not of particular interest because it results from the fact that a large fraction of epicenters occupy a relatively narrow strip, well seen on Fig. 1; therefore the observed 0–180° preferred direction has no connection to epicenter distribution within narrow space-time neighborhoods that we intend to analyze.To suppress the contribution of this interfering direction, a special normalization of angle histograms was performed. We additionally calculated similar histograms for larger delays, 100 to 150 days, marked T, considering these as representing pure effect of geometry of the epicenter field, and used them for normalization, performed in the following way. Values of the initial or raw (R histograms are divided (point by point by corresponding values of T-histograms. In this way the normalized (N histograms are obtained, considered as most representative of preferred directions of neighbor pairs. To make the results more convincing, we performed statistical testing of the hypothesis “N-histogram differs from a constant”; actually, the equivalent hypothesis “the R-histogram differs from the T-histogram” was tested. The Pearson’s c2 criterion was used. The significance value, Q, is indicated on plots, in most cases it is below 0.1 %. Such are the processing procedures employed; then the analysis of data was performed

  11. Nonsteroidal mycotoxin alternariol is a full androgen agonist in the yeast reporter androgen bioassay.

    Science.gov (United States)

    Stypuła-Trębas, Sylwia; Minta, Maria; Radko, Lidia; Jedziniak, Piotr; Posyniak, Andrzej

    2017-10-01

    Alternariol (AOH) is a toxic metabolite of phytopathogenic fungi of the Alternaria spp. and important contaminant of agricultural commodities. According to the recent studies, AOH has a potential to modulate the endocrine system of humans and animals. In the view of these reports, our study addressed the effects of AOH on human estrogen receptor (hERα) and androgen receptor (hAR) signaling with the use of the yeast estrogen and androgen reporter bioassays. Our results show that, apart from a weak estrogenic response, AOH induces full androgenic response of the bioassay with the EC50 of 269.4μM. The androgenic potency of AOH relative to testosterone (T) is 0.046%. Moreover, in the presence of T, AOH at 5μM acts as a weak antiandrogen, whereas at higher concentrations AOH sum up with the androgenic activity of T in a dose-dependent manner, suggesting additive effect. To our knowledge it is the first report of the androgenic potency of natural, nonsteroidal substance and may have the impact on the direction of the further studies. Further research is warranted to clarify the role of AOH in disruption of AR signaling in humans and animals. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Chip-based bioassay using bacterial sensor strains immobilized in three-dimensional microfluidic network.

    Science.gov (United States)

    Tani, Hirofumi; Maehana, Koji; Kamidate, Tamio

    2004-11-15

    A whole-cell bioassay has been performed using Escherichia coli sensor strains immobilized in a chip assembly, in which a silicon substrate is placed between two poly(dimethylsiloxane) (PDMS) substrates. Microchannels fabricated on the two separate PDMS layers are connected via perforated microwells on the silicon chip, and thus, a three-dimensional microfluidic network is constructed in the assembly. Bioluminescent sensor strains mixed with agarose are injected into the channels on one of the two PDMS layers and are immobilized in the microwells by gelation. Induction of the firefly luciferase gene expression in the sensor strains can be easily carried out by filling the channels on the other layer with sample solutions containing mutagen. Bioluminescence emissions from each well are detected after injection of luciferin/ATP mixtures into the channels. In this assay format using two multichannel layers and one microwell array chip, the interactions between various types of samples and strains can be monitored at each well on one assembly in a combinatorial fashion. Using several genotypes of the sensor strains or concentrations of mitomycin C in this format, the dependence of bioluminescence on these factors was obtained simultaneously in the single screening procedure. The present method could be a promising on-chip format for high-throughput whole-cell bioassays.

  13. On-chip bioassay using immobilized sensing bacteria in three-dimensional microfluidic network.

    Science.gov (United States)

    Tani, Hirofumi; Maehana, Koji; Kamidate, Tamio

    2007-01-01

    An on-chip whole-cell bioassay has been carried out using Escherichia coli tester strains for genotoxicity. In this assay format, the mutagen-responsive bioluminescence (BL) strains are immobilized in a chip assembly in which a silicon chip is placed between two poly(dimethylsiloxane) (PDMS) chips. In the chip assembly, microchannels fabricated on the two separate PDMS layers are connected via perforated microwells on the Si chip, and thus a three-dimensional microfluidic network is constructed. The strains mixed with agarose are loaded from the channels on one of the two PDMS layers into the wells on Si chip, followed by gelation. Induction of the expression of firefly luciferase in the tester strains and BL reaction are successively carried out by filling the channels on another PDMS layer with samples containing inducer (genotoxic substance) and then adenosine triphosphate/luciferin mixture, respectively. BL emission from each of the wells can be monitored by using a charge-coupled device camera to obtain an overall picture of the chip. The on-chip format based on a three-dimensional microfluidic network provides a combinatorial bioassay for multiple samples with multiple tester strains in a simple chip assembly. Thus, the presented method could be applied not only to various microbial sensing applications but also to other (bio)chemical analyses.

  14. In vitro bioassays reveal that additives are significant contributors to the toxicity of commercial household pesticides.

    Science.gov (United States)

    van de Merwe, Jason P; Neale, Peta A; Melvin, Steven D; Leusch, Frederic D L

    2018-03-28

    Pesticides commonly used around households can contain additives of unknown concentrations and toxicity. Given the likelihood of these chemicals washing into urban waterways, it is important to understand the effects that these additives may have on aquatic organisms. The aim of this study was to compare the toxicity of commercially available household pesticides to that of the active ingredient(s) alone. The toxicity of five household pesticides (three herbicides and two insecticides) was investigated using a bacterial cytotoxicity bioassay and an algal photosynthesis bioassay. The commercial products were up to an order of magnitude more toxic than the active ingredient(s) alone. In addition, two commercial products with the same listed active ingredients in the same ratio had a 600× difference in potency. These results clearly demonstrate that additives in commercial formulations are significant contributors to the toxicity of household pesticides. The toxicity of pesticides in aquatic systems is therefore likely underestimated by conventional chemical monitoring and risk assessment when only the active ingredients are considered. Regulators and customers should require more clarity from pesticide manufacturers about the nature and concentrations of not only the active ingredients, but also additives used in commercial formulations. In addition, monitoring programmes and chemical risk assessments schemes should develop a structured approach to assessing the toxic effects of commercial formulations, including additives, rather than simply those of the listed active ingredients. Copyright © 2018. Published by Elsevier B.V.

  15. Bioassay-Guided Isolated Compounds from Morinda officinalis Inhibit Alzheimer’s Disease Pathologies

    Directory of Open Access Journals (Sweden)

    Yoon Kyoung Lee

    2017-09-01

    Full Text Available Due to the side effects of synthetic drugs, the therapeutic potential of natural products for Alzheimer’s disease (AD has gained interest. Morinda officinalis has demonstrated inhibitory effects on geriatric diseases, such as bone loss and osteoporosis. However, although AD is a geriatric disease, M. officinalis has not been evaluated in an AD bioassay. Therefore, M. officinalis extracts and fractions were tested for AD-related activity, including inhibition of acetylcholinesterase (AChE, butyrylcholinesterase (BChE, β-site amyloid precursor protein cleaving enzyme 1 (BACE1, and advanced glycation end-product (AGE formation. A bioassay-guided approach led to isolation of 10 active compounds, eight anthraquinones (1–8, one coumarin (9, and one phytosterol (10, from n-hexane and ethyl acetate fractions of M. officinalis. The five anthraquinones (4–8 were stronger inhibitors of AChE than were other compounds. Compounds 3 and 9 were good inhibitors of BChE, and compounds 3 and 8 were good inhibitors of BACE1. Compounds 1–5 and 7–9 were more active than the positive control in inhibiting AGE formation. In addition, we first suggested a structure-activity relationship by which anthraquinones inhibit AChE and BACE1. Our findings demonstrate the preventive and therapeutic efficacy of M. officinalis for AD and its potential use as a natural alternative medicine.

  16. Evaluation and modeling of the parameters affecting fluoride toxicity level in aquatic environments by bioassay method

    Directory of Open Access Journals (Sweden)

    Hamid Reza Shamsollahi

    2014-04-01

    Full Text Available Background: Fluoride exists in various forms in nature and water resources. , The rising level of fluoride in water resources due to discharge of industrial effluents can cause toxicity in aquatic organisms. To prevent toxicity, it is necessary to determine maximum fluoride toxicity as well as effluent discharge limits. The aim of this study was to determine the maximum fluoride toxicity and the factors affecting fluoride toxicity to provide a model in order to determine the effluent discharge limits. Methods: Daphnia magna bioassay in the absence of confounding factors was used to determine the maximum level of fluoride toxicity. Then, bioassay was repeated in the presence of the confounding factors (hardness, temperature and exposure time to determine their effects. Results: In the absence of intervening factors, fluoride LC50 levels determined after 24, 48 and 72 hours exposure were 4.9, 46.5 and 38.7 mg/l, respectively.. Also, the influence of confounding factors on LC50 values was reported significant by Minitab software. Conclusion: Increasing the water hardness reduced fluoride toxicity, and increasing the water temperature and exposure time increased fluoride toxicity in aquatic environments. Therefore, while determining the wastewater discharge limit in terms of fluoride concentration, it is essential to take the effect of confounding factors on fluoride toxicity into account in order to prevent toxicity in the open water resources.

  17. Tradescantia-micronucleus (Trad-MCN) bioassay on clastogenicity of wastewater and in situ monitoring.

    Science.gov (United States)

    Ruiz, E F; Rabago, V M; Lecona, S U; Perez, A B; Ma, T H

    1992-11-01

    The Tradescantia-micronucleus (Trad-MCN) bioassay was used to determine the clastogenicity of wastewater samples collected from the Arena canal which contains effluent from the industrial district Benito Juarez of the city of Queretaro, Mexico. Fifteen wastewater samples which were collected, in most cases, at bi-weekly intervals beginning in September 1986 through February 1988, after a 3-fold dilution were used to treat Tradescantia plant cuttings. The clastogenicity expressed in terms of micronucleus frequencies of treated groups (30 h of treatment without recovery time) was significantly (0.01) higher than that of the tapwater control groups. The Trad-MCN bioassay was also used for in situ monitoring of air pollutants for the clastogenicity at 3 sites near the industrial and residential areas (Flores Magon, Conalep and Bellas Artes) of the city of Queretaro. Fourteen monitoring trips were made to each of the 3 sites at monthly intervals beginning in May 1988 through June 1990. Seasonal variation of micronucleus frequencies was exhibited with the peak clastogenicities shown in May and June 1988, June 1989 and April 1990 at the three sites. Micronucleus frequencies of all the exposed groups at the Conalep site, a predominantly industrial area, were markedly higher than that of the laboratory control groups throughout the 2-year period.

  18. Bioavailability of iron from spinach using an in vitro/human Caco-2 cell bioassay model

    Science.gov (United States)

    Rutzke, Corinne J.; Glahn, Raymond P.; Rutzke, Michael A.; Welch, Ross M.; Langhans, Robert W.; Albright, Louis D.; Combs, Gerald F Jr; Wheeler, Raymond M.

    2004-01-01

    Spinach (Spinacia oleracea) cv Whitney was tested for iron bioavailabilty using an in vitro human intestinal cell culture ferritin bioassay technique previously developed. Spinach was cultured in a growth chamber for 33 days, harvested, and freeze-dried. Total iron in the samples was an average of 71 micrograms/g dry weight. Spinach was digested in vitro (pepsin and 0.1 M HCl followed by pancreatin and 0.1 M NaHCO3) with and without the addition of supplemental ascorbic acid. Caco-2 cell cultures were used to determine iron bioavailability from the spinach mixtures. Production of the iron-binding protein ferritin in the Caco-2 cells showed the supplemental ascorbic acid doubled bioavailability of iron from spinach. The data show fresh spinach is a poor source of iron, and emphasize the importance of evaluation of whole meals rather than single food items. The data support the usefulness of the in vitro/Caco-2 cell ferritin bioassay model for prescreening of space flight diets for bioavailable iron.

  19. Soil-less bioassays for early screening for resistance to imazapyr in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Vega, Tatiana; Breccia, Gabriela; Nestares, Graciela; Mayor, María Laura; Zorzoli, Roxana; Picardi, Liliana

    2009-09-01

    Rapid and efficient diagnostic tests for early screening of herbicide resistance are convenient alternatives to field screening methods. There is a need for a quick, reliable and cost-effective method for rapid diagnosis of imidazolinone resistance in sunflower (Helianthus annuus L.). Two seed germination bioassays were developed. Seeds from three sunflower inbred lines differing in resistance to imidazolinones were germinated either on solid culture medium or placed in plastic pots filled with commercial perlite. After 8 days incubation under controlled conditions, both assays successfully distinguished susceptible genotype from the resistant and intermediate ones. The susceptible genotype showed arrested root growth at all herbicide treatments (root length resistant genotype developed a complete root system even when exposed to the highest dose of herbicide. However, no definite differences were observed for the intermediate and resistant genotypes with respect to root growth under the different herbicide treatments. The simple and rapid screening assays described in the present study were useful in discriminating imidazolinone resistance at the seedling stage. Therefore, these bioassays could be potential tools for early screening of imidazolinone resistance genes from large sunflower populations. Copyright 2009 Society of Chemical Industry.

  20. Estimation of cytotoxic potency by brine shrimp lethality bioassay application of Clerodendrum infortunatum Linn.

    Directory of Open Access Journals (Sweden)

    Talukdar Muhammad Waliullah

    2015-08-01

    Full Text Available Objective: To learn a scientific and systematic knowledge of anticancer, antimicrobial and pharmacological activities of natural products and estimate cytotoxic potency by using ethanol and chloroform extracts of root, leaf and stem of Clerodendrum infortunatum (Verbenaceae due to its random use in customary and traditional medicine to cure common ailments such as intestinal disorder, diarrhea, tuberculosis and respiratory problems etc. Methods: The in vitro application was carried out with the bench-top bioassay method by using brine shrimp lethality bioassay. Results: All of the crude extracts were found to be lethal and effective. The LC50 value of ethyl alcohol fraction of root was 20.845 mg/L compared to the standard drug tetracycline of 14.675 mg/L to brine shrimp nauplii, indicating that the extracts were biologically active. Conclusions: The cytotoxic study of LC50 value showed that a good correlation with the antibiotic tetracycline. From the comparative correlation error bars and percentage, we understood that ethyl alcohol fraction of root extract was very effective. This study serves as a basis for further research to lead compounds to be isolated so that it may be as a template for the implications of these results for bioactivity and drug discovery potential of herbal products.

  1. Bioassay standardization for the detection of allelopathic compounds and environmental toxicants using lettuce

    Directory of Open Access Journals (Sweden)

    Mateus Salomão Simões

    2013-09-01

    Full Text Available The purpose of this study was to assess different experimental conditions to determine a protocol for bioassays based on seed germination and early seedling growth using lettuce (Lactuca sativa L. cv. Grand Rapids as indicator species. This protocol aims to provide support for the standardization of assays of various chemicals such as allelochemicals and environmental toxicants. The following tests were performed: time of germination, temperature, light, solution volume and Petri dish size. For each test (except for time of germination, the influence of the conditions investigated was determined by the endpoints germination percentage, germination speed index, root length, seedling fresh weight and total dry weight. The results showed that variations in the methods altered the results. It is recommended that bioassays using L. sativa L. cv. Grand Rapids be carried out for a minimum period of four days for assessments of both germination and initial growth and that the experimental conditions include a temperature of 20°C, 90-mm Petri dishes or larger, 0.1 mL cypsela solution, and continuous light or 12-hour photoperiod.

  2. In vitro and in vivo protocols of antimicrobial bioassay of medicinal herbal extracts: A review

    Directory of Open Access Journals (Sweden)

    Najeeb Ullah

    2016-08-01

    Full Text Available Antimicrobial susceptibility testing against pathogenic microorganisms is the most significant task of clinical microbiology laboratory. The present study was therefore designed to review the in vitro and in vivo protocols of antimicrobial bioassays of various medicinal herbal extracts against a diversity of pathogenic microorganisms. Plants have a broad variety of antimicrobial agents which are extensively used as herbal drugs against different microbes. The review covers the antimicrobial techniques and antimicrobial bioassays of medicinal herbal extracts against different bacterial and fungal strains from 2000 onward. Plants have diverse concentrations of bioactive constituents such as alkaloids, saponins, tannins, terpenoids, steroids, carbohydrates, proteins and lipids. These phytochemicals are used against an extensive range of bacteria (Escherichia coli, Mycobacterium, Corynebacterium pervum, Bordetella pertusis, Klebsiella pneumoniae, Salmonella typhi, viruses (simian-virus, retrovirus and fungi (Pseudomonas aeruginosa, Aspergillus fumigatus, Aspergillus flavus, Fusarium solani. A variety of antibiotics (tetracycline, terramycin, ampicillin has also been isolated from different medicinal plants. This review was therefore intended to explore the techniques used for antimicrobial activities of herbal medicinal extracts.

  3. Relative proportions of polycyclic aromatic hydrocarbons differ between accumulation bioassays and chemical methods to predict bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Eyles, Jose L., E-mail: j.l.gomezeyles@reading.ac.u [University of Reading, School of Human and Environmental Sciences, Department of Soil Science, Reading RG6 6DW, Berkshire (United Kingdom); Collins, Chris D.; Hodson, Mark E. [University of Reading, School of Human and Environmental Sciences, Department of Soil Science, Reading RG6 6DW, Berkshire (United Kingdom)

    2010-01-15

    Chemical methods to predict the bioavailable fraction of organic contaminants are usually validated in the literature by comparison with established bioassays. A soil spiked with polycyclic aromatic hydrocarbons (PAHs) was aged over six months and subjected to butanol, cyclodextrin and tenax extractions as well as an exhaustive extraction to determine total PAH concentrations at several time points. Earthworm (Eisenia fetida) and rye grass root (Lolium multiflorum) accumulation bioassays were conducted in parallel. Butanol extractions gave the best relationship with earthworm accumulation (r{sup 2} <= 0.54, p <= 0.01); cyclodextrin, butanol and acetone-hexane extractions all gave good predictions of accumulation in rye grass roots (r{sup 2} <= 0.86, p <= 0.01). However, the profile of the PAHs extracted by the different chemical methods was significantly different (p < 0.01) to that accumulated in the organisms. Biota accumulated a higher proportion of the heavier 4-ringed PAHs. It is concluded that bioaccumulation is a complex process that cannot be predicted by measuring the bioavailable fraction alone. - The ability of chemical methods to predict PAH accumulation in Eisenia fetida and Lolium multiflorum was hindered by the varied metabolic fate of the different PAHs within the organisms.

  4. DOSEXPRT: A bioassay dosimetry code for Martin Marietta Energy Systems, Inc.

    Energy Technology Data Exchange (ETDEWEB)

    Ward, R.C.; Eckerman, K.F.

    1992-04-01

    The bioassay code DOSEXPRT was developed for Martin Marietta Energy Systems, Inc., to provide compliance with Department of Energy (DOE) Order 5480, Chapter 11. DOSEXPRT computes the intake of a radionuclide in any year (considering both acute and chronic intakes) from in vivo measurements of the retained activity and/or measurements of the activity in excreta. The committed effective and organ doses for the intake are computed as well as the effective and organ doses expected to be received in each calendar year out to 50 years beyond the year of intake. The bioassay records used as input for DOSEXPRT are extracted from the Martin Marietta Energy Systems Occupational Health Information System (OHIS). DOSEXPRT implements a set of algorithms with parameters governing the translocation, retention, and excretion of the nuclide contained in data files specific to the nuclide. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent for the intakes in the year. Annual organ and effective doses are computed using additional dose-rate files that contain data on the dose rate at various times following a unit intake. If measurements are presented for more than one assay for a given nuclide, DOSEXPRT estimates the intake by applying weights assigned in the nuclide file for each assay. DOSEXPRT is accessed off the OHIS MENU No. 4 and designed to be run as a batch processor, but can also be run interactively for testing purposes.

  5. DOSEXPRT: A bioassay dosimetry code for Martin Marietta Energy Systems, Inc

    Energy Technology Data Exchange (ETDEWEB)

    Ward, R.C.; Eckerman, K.F.

    1992-04-01

    The bioassay code DOSEXPRT was developed for Martin Marietta Energy Systems, Inc., to provide compliance with Department of Energy (DOE) Order 5480, Chapter 11. DOSEXPRT computes the intake of a radionuclide in any year (considering both acute and chronic intakes) from in vivo measurements of the retained activity and/or measurements of the activity in excreta. The committed effective and organ doses for the intake are computed as well as the effective and organ doses expected to be received in each calendar year out to 50 years beyond the year of intake. The bioassay records used as input for DOSEXPRT are extracted from the Martin Marietta Energy Systems Occupational Health Information System (OHIS). DOSEXPRT implements a set of algorithms with parameters governing the translocation, retention, and excretion of the nuclide contained in data files specific to the nuclide. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent for the intakes in the year. Annual organ and effective doses are computed using additional dose-rate files that contain data on the dose rate at various times following a unit intake. If measurements are presented for more than one assay for a given nuclide, DOSEXPRT estimates the intake by applying weights assigned in the nuclide file for each assay. DOSEXPRT is accessed off the OHIS MENU No. 4 and designed to be run as a batch processor, but can also be run interactively for testing purposes.

  6. Use of a germination bioassay to test compost maturity in Tekelan Village

    Science.gov (United States)

    Oktiawan, Wiharyanto; Zaman, Badrus; Purwono

    2018-02-01

    Livestock waste from cattle farms in Tekelan village, Getasan Subdistrict, Semarang Regency can be grouped into three types, namely solid waste, slurry and waste water. Solid waste (cow dung) was processed into compost, while slurry and waste water were used to make liquid fertilizer. This compost was used as a component of planting media in horticultural crops and potted plants production. We evaluated the toxicity (phytochemical and ecotoxicological) test of compost by using germination index (GI). Vigna radiata seeds are sown on filter paper dampened with compost extract for different times. GI was calculated by relative germination (G) and relative radical length (L). The germination index (GI) = G / G0 x L / L0 x 100, where G0 and L0 are values obtained by distilled water as a control. The results showed that germination bioassay and radical length using aquades and groundwater in Tekelan village did not affect the radical length of Vigna radiata . Technically, groundwater in Tekelan village can be used as a germination bioassay control. The cow dung compost substrate appears to have a major influence on compost toxicity. Mature compost was produced on day 14 with a GI of 104.03.

  7. Screening the Toxicity of Selected Personal Care Products Using Embryo Bioassays: 4-MBC, Propylparaben and Triclocarban

    Directory of Open Access Journals (Sweden)

    Tiago Torres

    2016-10-01

    Full Text Available Recently, several emerging pollutants, including Personal Care Products (PCPs, have been detected in aquatic ecosystems, in the ng/L or µg/L range. Available toxicological data is limited, and, for certain PCPs, evidence indicates a potential risk for the environment. Hence, there is an urgent need to gather ecotoxicological data on PCPs as a proxy to improve risk assessment. Here, the toxicity of three different PCPs (4-Methylbenzylidene Camphor (4-MBC, propylparaben and triclocarban was tested using embryo bioassays with Danio rerio (zebrafish and Paracentrotus lividus (sea urchin. The No Observed Effect Concentration (NOEC for triclocarban was 0.256 µg/L for sea urchin and 100 µg/L for zebrafish, whereas NOEC for 4-MBC was 0.32 µg/L for sea urchin and 50 µg/L for zebrafish. Both PCPs impacted embryo development at environmentally relevant concentrations. In comparison with triclocarban and 4-MBC, propylparaben was less toxic for both sea urchin (NOEC = 160 µg/L and zebrafish (NOEC = 1000 µg/L. Overall, this study further demonstrates the sensitivity of embryo bioassays as a high-throughput approach for testing the toxicity of emerging pollutants.

  8. A bioassay for the detection of benzimidazoles reveals their presence in a range of environmental samples

    Directory of Open Access Journals (Sweden)

    Terence S Crofts

    2014-11-01

    Full Text Available Cobamides are a family of enzyme cofactors that include vitamin B12 (cobalamin and are produced solely by prokaryotes. Structural variability in the lower axial ligand has been observed in cobamides produced by diverse organisms. Of the three classes of lower ligands, the benzimidazoles are uniquely found in cobamides, whereas the purine and phenolic bases have additional biological functions. Many organisms acquire cobamides by salvaging and remodeling cobamides or their precursors from the environment. These processes require free benzimidazoles for incorporation as lower ligands, though the presence of benzimidazoles in the environment has not been previously investigated. Here, we report a new purification method and bioassay to measure the total free benzimidazole content of samples from microbial communities and laboratory media components. The bioassay relies on the calcofluor-bright phenotype of a bluB mutant of the model cobalamin-producing bacterium Sinorhizobium meliloti. The concentrations of individual benzimidazoles in these samples were measured by liquid chromatography-tandem mass spectrometry. Several benzimidazoles were detected in subpicomolar to subnanomolar concentrations in host-associated and environmental samples. In addition, benzimidazoles were found to be common contaminants of laboratory media components. These results suggest that benzimidazoles present in the environment and in laboratory media have the potential to influence microbial metabolic activities.

  9. Mimicking Daphnia magna bioassay performance by an electronic tongue for urban water quality control

    Energy Technology Data Exchange (ETDEWEB)

    Kirsanov, Dmitry, E-mail: d.kirsanov@gmail.com [Laboratory of Chemical Sensors, St. Petersburg State University, St. Petersburg (Russian Federation); Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation); Legin, Evgeny [Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation); Sensor Systems LLC, St. Petersburg (Russian Federation); Zagrebin, Anatoly; Ignatieva, Natalia; Rybakin, Vladimir [Institute of Limnology, Russian Academy of Sciences, St. Petersburg (Russian Federation); Legin, Andrey [Laboratory of Chemical Sensors, St. Petersburg State University, St. Petersburg (Russian Federation); Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation)

    2014-05-01

    Highlights: • -Daphnia magna bioassay can be simulated with multisensor system. • Urban water toxicity can be predicted from potentiometric ET data. • Independent test set validation confirms statistical significance of the results. - Abstract: Toxicity is one of the key parameters of water quality in environmental monitoring. However, being evaluated as a response of living beings (as their mobility, fertility, death rate, etc.) to water quality, toxicity can only be assessed with the help of these living beings. This imposes certain restrictions on toxicity bioassay as an analytical method: biotest organisms must be properly bred, fed and kept under strictly regulated conditions and duration of tests can be quite long (up to several days), thus making the whole procedure the prerogative of the limited number of highly specialized laboratories. This report describes an original application of potentiometric multisensor system (electronic tongue) when the set of electrochemical sensors was calibrated against Daphnia magna death rate in order to perform toxicity assessment of urban waters without immediate involvement of living creatures. PRM (partial robust M) and PLS (projections on latent structures) regression models based on the data from this multisensor system allowed for prediction of toxicity of unknown water samples in terms of biotests but in the fast and simple instrumental way. Typical errors of water toxicity predictions were below 20% in terms of Daphnia death rate which can be considered as a good result taking into account the complexity of the task.

  10. Bioassay and characterization of soil microorganisms involved in the biodegradation of the fungicide, metalaxyl

    International Nuclear Information System (INIS)

    Bailey, A.M.

    1985-01-01

    A sensitive bioassay was developed to detect low concentrations of metalaxyl in soils. The quantitative estimation of metalaxyl in soils was based on a significant positive relationship between the radial growth of Phytophthora boehmeriae and the log concentration of the fungicide in the agar. The isolate of P. boehmeriae was chosen for its sensitivity to metalaxyl as manifested in a linear growth response on cornmeal agar over a range of 2 to 30 ng/ml. The sensitivity and quantitative nature of the bioassay was confirmed by comparison with data obtained by using 14 C-metalaxyl. Metabolism of metalaxyl was detected in three of five avocado soils that had repeated applications of the fungicide over 2-5 yr. The average disappearance of metalaxyl was 28 days, and in the most active soils was 14 days. The composition and level of the microbial populations of soils, either active or inactive in the breakdown of metalaxyl, did not differ. Fungal and bacterial microflora recovered from these two soils by use of either selective media or filtration techniques were capable of metabolizing metalaxyl over a 45-day period

  11. Bioassay-guided fractionation of a thymol-deprived hydrophilic thyme extract and its antispasmodic effect.

    Science.gov (United States)

    Engelbertz, Jonas; Lechtenberg, Matthias; Studt, Lena; Hensel, Andreas; Verspohl, Eugen J

    2012-06-14

    Extracts from Thymus vulgaris L. and Thymus zygis L. are traditionally used for bronchitis, catarrhs of the respiratory tract and supportive treatment of pertussis. A potential spasmolytic effect is thought to be due to the presence of the monoterpenoid phenols thymol and carvacrol in the extract. Based on previous data the present investigation aimed to clarify if thymol-deprived thyme extracts (as been in use within German drug market) have antispasmodic activity. Additionally compounds responsible for this effect had to be identified. Thyme fluid extract was subsequently fractionated by FCPC, LPLC, and HPLC and compounds isolated were identified by spectroscopic methods. Bioassay testing was done by quantification of antispasmodic activity in the preconstricted rat smooth muscle trachea model against papaverin as positive control. Thymol-deprived spissum extract (SE) had good antispasmodic activity (-37%, related to the maximum contraction). Bioassay-guided fractionation indicated that rosmarinic acid and apigenin do not contribute to this effect. Luteolin contributed significantly to the antispasmodic activity (-9%). Thyme extracts have antispasmodic activity, which is at least due to synergistic effects of phenolic volatile oil compounds and the flavone luteolin. Specifications of thyme-containing preparations should refer to this flavone in addition to focusing on the volatile phenols. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Use of a germination bioassay to test compost maturity in Tekelan Village

    Directory of Open Access Journals (Sweden)

    Oktiawan Wiharyanto

    2018-01-01

    Full Text Available Livestock waste from cattle farms in Tekelan village, Getasan Subdistrict, Semarang Regency can be grouped into three types, namely solid waste, slurry and waste water. Solid waste (cow dung was processed into compost, while slurry and waste water were used to make liquid fertilizer. This compost was used as a component of planting media in horticultural crops and potted plants production. We evaluated the toxicity (phytochemical and ecotoxicological test of compost by using germination index (GI. Vigna radiata seeds are sown on filter paper dampened with compost extract for different times. GI was calculated by relative germination (G and relative radical length (L. The germination index (GI = G / G0 x L / L0 x 100, where G0 and L0 are values obtained by distilled water as a control. The results showed that germination bioassay and radical length using aquades and groundwater in Tekelan village did not affect the radical length of Vigna radiata . Technically, groundwater in Tekelan village can be used as a germination bioassay control. The cow dung compost substrate appears to have a major influence on compost toxicity. Mature compost was produced on day 14 with a GI of 104.03.

  13. Assessing the potential risk of oil-field produced waters using a battery of bioassays/biomarkers.

    Science.gov (United States)

    Li, Jian; Ma, Mei; Cui, Qing; Wang, Zijian

    2008-06-01

    A battery of in vitro bioassays was conducted to assess the potential risks of organic extracts from oilfield produced wastewaters and from the receiving waters. In SOS/umu bioassay for the genotoxicity, our results showed that direct and indirect genotoxic substances were observed and metabolic activation greatly enhanced the genotoxic effects. In Ethoxyresorufin-O-deethylase bioassay, levels of AhR-agonists, expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalences, varied from 13.3 to 16.7 pg L(-1). We conclude that oilfield produced wastewater contains substantial quantity of indirect genotoxic substances exclusive of AhR agonists. Both genotoxic and AhR agonistic chemicals could not be effectively removed by the treatment processes.

  14. Combining ability in maize for fall armyworm and southwestern corn borer resistance based on a laboratory bioassay for larval growth.

    Science.gov (United States)

    Williams, W P; Buckley, P M; Davis, F M

    1995-02-01

    The fall armyworm, Spodoptera frugiperda (J. E. Smith), and southwestern corn borer, Diatraea grandiosella Dyar, are major insect pests of maize, Zea mays L., in the southern USA. Both insects feed extensively on leaves of plants in the whorl stage of growth. A diallel cross of seven inbred lines with different levels of susceptibility to leaf feeding damage in the field was evaluated in a laboratory bioassay for fall armyworm and southwestern corn borer larval growth. Diets were prepared from lyophilized leaf tissue of field-grown plants of the inbred lines and their 21 F1 hybrids. One inbred line, Tx601, exhibited heavy leaf damage in field tests but showed moderate resistance in the laboratory bioassay. Both general and specific combining ability were highly significant sources of variation in the inheritance of fall armyworm and south-western corn borer larval growth in the laboratory bioassay. Tx601 showed excellent general combining ability for reduced larval growth of both species.

  15. Intemational collaborative study on the preparation of 1st international standard for rhTSH for bioassay

    International Nuclear Information System (INIS)

    Huang Ying; Shen Hongzheng; Yu Ting; Xu Ligen

    2007-01-01

    The history of the international collaborative studies on the preparation of standards of TSH for bioassay and immunoassay was reviewed. The result of collaborative study on the 1st international standard for thyroid-stimulating hormone, recombinant, human, for bioassay was reported in detail in this article. Based on the results of this collaborative study, it is proposed that the candidate standard be established as the international standard for rhTSH for bioassay, and be assigned an activity of 9.5 IU per ampoule. The national standard preparation of TSH for immunoassay was also reassayed, revealing the potency to be 0.557 mIU/ampoule, i.e. 92. 8% of the labelled value of 0.600mIU/ampoule, a reasonable consistency. (authors)

  16. Design of an enhanced fuzzy k-nearest neighbor classifier based computer aided diagnostic system for thyroid disease.

    Science.gov (United States)

    Liu, Da-You; Chen, Hui-Ling; Yang, Bo; Lv, Xin-En; Li, Li-Na; Liu, Jie

    2012-10-01

    In this paper, we present an enhanced fuzzy k-nearest neighbor (FKNN) classifier based computer aided diagnostic (CAD) system for thyroid disease. The neighborhood size k and the fuzzy strength parameter m in FKNN classifier are adaptively specified by the particle swarm optimization (PSO) approach. The adaptive control parameters including time-varying acceleration coefficients (TVAC) and time-varying inertia weight (TVIW) are employed to efficiently control the local and global search ability of PSO algorithm. In addition, we have validated the effectiveness of the principle component analysis (PCA) in constructing a more discriminative subspace for classification. The effectiveness of the resultant CAD system, termed as PCA-PSO-FKNN, has been rigorously evaluated against the thyroid disease dataset, which is commonly used among researchers who use machine learning methods for thyroid disease diagnosis. Compared to the existing methods in previous studies, the proposed system has achieved the highest classification accuracy reported so far via 10-fold cross-validation (CV) analysis, with the mean accuracy of 98.82% and with the maximum accuracy of 99.09%. Promisingly, the proposed CAD system might serve as a new candidate of powerful tools for diagnosing thyroid disease with excellent performance.

  17. Backpacking in Yosemite and Kings Canyon National Parks and neighboring wilderness areas: how safe is the water to drink?

    Science.gov (United States)

    Derlet, Robert W

    2008-01-01

    The objective of this study was to determine the risk of acquiring disease from popular Sierra Nevada wilderness area lakes and streams. This study examines the relative risk factors for harmful waterborne microorganisms using coliforms as an indicator. Water was collected in the backcountry Yosemite and Kings Canyon National Parks and neighboring wilderness areas. A total of 72 sites from lakes or streams were selected to statistically differentiate the risk categories: (1) natural areas rarely visited by humans or domestic animals; (2) human day use-only areas; (3) high use by backpackers; (4) high use by pack animals; and (5) cattle- and sheep-grazing tracts. Water was collected in sterile test tubes and Millipore coliform samplers during the summer of 2006. Water was analyzed at the university microbiology lab, where bacteria were harvested and then subjected to analysis using standardized techniques. Statistical analysis to compare site categories was performed using Fisher's exact test. Coliforms were found in none of the 13 wild sites, none of the 12 day hike sites, and only 3 of 18 backpacker sites (17%). In contrast, 14 of 20 sites (70%) with pack animal traffic yielded coliforms, and all 9 sites (100%) below the cattle-grazing areas grew coliforms. Differences between backpacker versus cattle or pack areas were significant, p backpack areas showed far less risk for coliforms.

  18. A Novel Quantum Solution to Privacy-Preserving Nearest Neighbor Query in Location-Based Services

    Science.gov (United States)

    Luo, Zhen-yu; Shi, Run-hua; Xu, Min; Zhang, Shun

    2018-04-01

    We present a cheating-sensitive quantum protocol for Privacy-Preserving Nearest Neighbor Query based on Oblivious Quantum Key Distribution and Quantum Encryption. Compared with the classical related protocols, our proposed protocol has higher security, because the security of our protocol is based on basic physical principles of quantum mechanics, instead of difficulty assumptions. Especially, our protocol takes single photons as quantum resources and only needs to perform single-photon projective measurement. Therefore, it is feasible to implement this protocol with the present technologies.

  19. A method of neighbor classes based SVM classification for optical printed Chinese character recognition.

    Science.gov (United States)

    Zhang, Jie; Wu, Xiaohong; Yu, Yanmei; Luo, Daisheng

    2013-01-01

    In optical printed Chinese character recognition (OPCCR), many classifiers have been proposed for the recognition. Among the classifiers, support vector machine (SVM) might be the best classifier. However, SVM is a classifier for two classes. When it is used for multi-classes in OPCCR, its computation is time-consuming. Thus, we propose a neighbor classes based SVM (NC-SVM) to reduce the computation consumption of SVM. Experiments of NC-SVM classification for OPCCR have been done. The results of the experiments have shown that the NC-SVM we proposed can effectively reduce the computation time in OPCCR.

  20. A method of neighbor classes based SVM classification for optical printed Chinese character recognition.

    Directory of Open Access Journals (Sweden)

    Jie Zhang

    Full Text Available In optical printed Chinese character recognition (OPCCR, many classifiers have been proposed for the recognition. Among the classifiers, support vector machine (SVM might be the best classifier. However, SVM is a classifier for two classes. When it is used for multi-classes in OPCCR, its computation is time-consuming. Thus, we propose a neighbor classes based SVM (NC-SVM to reduce the computation consumption of SVM. Experiments of NC-SVM classification for OPCCR have been done. The results of the experiments have shown that the NC-SVM we proposed can effectively reduce the computation time in OPCCR.