WorldWideScience

Sample records for subgradient method leads

  1. An effective line search for the subgradient method

    OpenAIRE

    Beltran, C; Heredia, F.-Javier (Francisco Javier)

    2005-01-01

    One of the main drawbacks of the subgradient method is the tuning process to determine the sequence of steplengths. In this paper, the radar subgradient method, a heuristic method designed to compute a tuning-free subgradient steplength, is geometrically motivated and algebraically deduced. The unit commitment problem, which arises in the electrical engineering field, is used to compare the performance of the subgradient method with the new radar subgradient method. Pe...

  2. Approximate Subgradient Methods for Lagrangian Relaxations on Networks

    Science.gov (United States)

    Mijangos, Eugenio

    Nonlinear network flow problems with linear/nonlinear side con- straints can be solved by means of Lagrangian relaxations. The dual problem is the maximization of a dual function whose value is estimated by minimizing approximately a Lagrangian function on the set defined by the network constraints. We study alternative stepsizes in the approximate subgradient methods to solve the dual problem. Some basic convergence results are put forward. Moreover, we compare the quality of the computed solutions and the efficiency of these methods.

  3. A modified subgradient extragradient method for solving monotone variational inequalities.

    Science.gov (United States)

    He, Songnian; Wu, Tao

    2017-01-01

    In the setting of Hilbert space, a modified subgradient extragradient method is proposed for solving Lipschitz-continuous and monotone variational inequalities defined on a level set of a convex function. Our iterative process is relaxed and self-adaptive, that is, in each iteration, calculating two metric projections onto some half-spaces containing the domain is involved only and the step size can be selected in some adaptive ways. A weak convergence theorem for our algorithm is proved. We also prove that our method has [Formula: see text] convergence rate.

  4. A modified subgradient extragradient method for solving monotone variational inequalities

    Directory of Open Access Journals (Sweden)

    Songnian He

    2017-04-01

    Full Text Available Abstract In the setting of Hilbert space, a modified subgradient extragradient method is proposed for solving Lipschitz-continuous and monotone variational inequalities defined on a level set of a convex function. Our iterative process is relaxed and self-adaptive, that is, in each iteration, calculating two metric projections onto some half-spaces containing the domain is involved only and the step size can be selected in some adaptive ways. A weak convergence theorem for our algorithm is proved. We also prove that our method has O ( 1 n $O(\\frac{1}{n}$ convergence rate.

  5. Adaptive Subgradient Methods for Online AUC Maximization

    OpenAIRE

    Ding, Yi; Zhao, Peilin; Hoi, Steven C. H.; Ong, Yew-Soon

    2016-01-01

    Learning for maximizing AUC performance is an important research problem in Machine Learning and Artificial Intelligence. Unlike traditional batch learning methods for maximizing AUC which often suffer from poor scalability, recent years have witnessed some emerging studies that attempt to maximize AUC by single-pass online learning approaches. Despite their encouraging results reported, the existing online AUC maximization algorithms often adopt simple online gradient descent approaches that...

  6. Regularized Primal-Dual Subgradient Method for Distributed Constrained Optimization.

    Science.gov (United States)

    Yuan, Deming; Ho, Daniel W C; Xu, Shengyuan

    2016-09-01

    In this paper, we study the distributed constrained optimization problem where the objective function is the sum of local convex cost functions of distributed nodes in a network, subject to a global inequality constraint. To solve this problem, we propose a consensus-based distributed regularized primal-dual subgradient method. In contrast to the existing methods, most of which require projecting the estimates onto the constraint set at every iteration, only one projection at the last iteration is needed for our proposed method. We establish the convergence of the method by showing that it achieves an O ( K (-1/4) ) convergence rate for general distributed constrained optimization, where K is the iteration counter. Finally, a numerical example is provided to validate the convergence of the propose method.

  7. The Subgradient Extragradient Method for Solving Variational Inequalities in Hilbert Space.

    Science.gov (United States)

    Censor, Y; Gibali, A; Reich, S

    2011-02-01

    We present a subgradient extragradient method for solving variational inequalities in Hilbert space. In addition, we propose a modified version of our algorithm that finds a solution of a variational inequality which is also a fixed point of a given nonexpansive mapping. We establish weak convergence theorems for both algorithms.

  8. An Interior Projected-Like Subgradient Method for Mixed Variational Inequalities

    Directory of Open Access Journals (Sweden)

    Guo-ji Tang

    2014-01-01

    Full Text Available An interior projected-like subgradient method for mixed variational inequalities is proposed in finite dimensional spaces, which is based on using non-Euclidean projection-like operator. Under suitable assumptions, we prove that the sequence generated by the proposed method converges to a solution of the mixed variational inequality. Moreover, we give the convergence estimate of the method. The results presented in this paper generalize some recent results given in the literatures.

  9. On The Behavior of Subgradient Projections Methods for Convex Feasibility Problems in Euclidean Spaces.

    Science.gov (United States)

    Butnariu, Dan; Censor, Yair; Gurfil, Pini; Hadar, Ethan

    2008-07-03

    We study some methods of subgradient projections for solving a convex feasibility problem with general (not necessarily hyperplanes or half-spaces) convex sets in the inconsistent case and propose a strategy that controls the relaxation parameters in a specific self-adapting manner. This strategy leaves enough user-flexibility but gives a mathematical guarantee for the algorithm's behavior in the inconsistent case. We present numerical results of computational experiments that illustrate the computational advantage of the new method.

  10. A trust region method using subgradient for minimizing a nondifferentiable function

    Directory of Open Access Journals (Sweden)

    Gardašević-Filipović Milanka

    2009-01-01

    Full Text Available The minimization of a particular nondifferentiable function is considered. The first and second order necessary conditions are given. A trust region method for minimization of this form of the objective function is presented. The algorithm uses the subgradient instead of the gradient. It is proved that the sequence of points generated by the algorithm has an accumulation point which satisfies the first and second order necessary conditions.

  11. Multi-Domain Adaptive Learning Based on Feasibility Splitting and Adaptive Projected Subgradient Method

    Science.gov (United States)

    Yukawa, Masahiro; Slavakis, Konstantinos; Yamada, Isao

    We propose the multi-domain adaptive learningthat enables us to find a point meeting possibly time-varying specifications simultaneously in multiple domains, e.g. space, time, frequency, etc. The novel concept is based on the idea of feasibility splitting — dealing with feasibility in each individual domain. We show that the adaptive projected subgradient method(Yamada, 2003) realizes the multi-domain adaptive learning by employing (i) a projected gradient operator with respect to a ‘fixed’ proximity function reflecting the time-invariant specifications and (ii) a subgradient projection with respect to ‘time-varying’ objective functions reflecting the time-varying specifications. The resulting algorithm is suitable for real-time implementation, because it requires no more than metric projections onto closed convex sets each of which accommodates the specification in each domain. A convergence analysis and numerical examples are presented.

  12. Distributed Primal-Dual Subgradient Method for Multiagent Optimization via Consensus Algorithms.

    Science.gov (United States)

    Deming Yuan; Shengyuan Xu; Huanyu Zhao

    2011-12-01

    This paper studies the problem of optimizing the sum of multiple agents' local convex objective functions, subject to global convex inequality constraints and a convex state constraint set over a network. Through characterizing the primal and dual optimal solutions as the saddle points of the Lagrangian function associated with the problem, we propose a distributed algorithm, named the distributed primal-dual subgradient method, to provide approximate saddle points of the Lagrangian function, based on the distributed average consensus algorithms. Under Slater's condition, we obtain bounds on the convergence properties of the proposed method for a constant step size. Simulation examples are provided to demonstrate the effectiveness of the proposed method.

  13. Approximate Dual Averaging Method for Multiagent Saddle-Point Problems with Stochastic Subgradients

    Directory of Open Access Journals (Sweden)

    Deming Yuan

    2014-01-01

    Full Text Available This paper considers the problem of solving the saddle-point problem over a network, which consists of multiple interacting agents. The global objective function of the problem is a combination of local convex-concave functions, each of which is only available to one agent. Our main focus is on the case where the projection steps are calculated approximately and the subgradients are corrupted by some stochastic noises. We propose an approximate version of the standard dual averaging method and show that the standard convergence rate is preserved, provided that the projection errors decrease at some appropriate rate and the noises are zero-mean and have bounded variance.

  14. A primal sub-gradient method for structured classification with the averaged sum loss

    Directory of Open Access Journals (Sweden)

    Mančev Dejan

    2014-12-01

    Full Text Available We present a primal sub-gradient method for structured SVM optimization defined with the averaged sum of hinge losses inside each example. Compared with the mini-batch version of the Pegasos algorithm for the structured case, which deals with a single structure from each of multiple examples, our algorithm considers multiple structures from a single example in one update. This approach should increase the amount of information learned from the example. We show that the proposed version with the averaged sum loss has at least the same guarantees in terms of the prediction loss as the stochastic version. Experiments are conducted on two sequence labeling problems, shallow parsing and part-of-speech tagging, and also include a comparison with other popular sequential structured learning algorithms.

  15. Solving Unit Commitment Problem Using Modified Subgradient Method Combined with Simulated Annealing Algorithm

    Directory of Open Access Journals (Sweden)

    Ümmühan Başaran Filik

    2010-01-01

    Full Text Available This paper presents the solving unit commitment (UC problem using Modified Subgradient Method (MSG method combined with Simulated Annealing (SA algorithm. UC problem is one of the important power system engineering hard-solving problems. The Lagrangian relaxation (LR based methods are commonly used to solve the UC problem. The main disadvantage of this group of methods is the difference between the dual and the primal solution which gives some significant problems on the quality of the feasible solution. In this paper, MSG method which does not require any convexity and differentiability assumptions is used for solving the UC problem. MSG method depending on the initial value reaches zero duality gap. SA algorithm is used in order to assign the appropriate initial value for MSG method. The major advantage of the proposed approach is that it guarantees the zero duality gap independently from the size of the problem. In order to show the advantages of this proposed approach, the four-unit Tuncbilek thermal plant and ten-unit thermal plant which is usually used in literature are chosen as test systems. Penalty function (PF method is also used to compare with our proposed method in terms of total cost and UC schedule.

  16. Feasible Modified Subgradient Method for Solving the Thermal Unit Commitment Problem as a New Approach

    Directory of Open Access Journals (Sweden)

    Ummuhan Basaran Filik

    2010-01-01

    Full Text Available The Lagrangian relaxation- (LR- based methods are commonly used to solve the thermal unit commitment (UC problem which is an important subject in power system engineering. The main drawback of this group of methods is the difference between the dual and the primal solutions which gives some significant problems on the quality of the feasible solutions. In this paper, a new approach, feasible modified subgradient (F-MSG method which does not require finding an unconstrained global minimum of the Lagrangian function and knowing an optimal value of the problem under consideration in order to update dual variables at the each iteration, is firstly used for solving the thermal UC problem. The major advantage of the proposed approach is that it guarantees the zero duality gap and convergence independently from the size of the problem. In order to discuss the advantages of this method, the four-unit Tuncbilek thermal plant, which is located in Kutahya region in Turkey, is chosen as a small test system. The numerical results show that F-MSG gives better solutions as compared to the standard LR method.

  17. Modified Spectral Projected Subgradient Method: Convergence Analysis and Momentum Parameter Heuristics

    Directory of Open Access Journals (Sweden)

    Milagros Loreto

    2016-09-01

    Full Text Available The Modified Spectral Projected Subgradient (MSPS was proposed to solve Langrangen Dual Problems, and its convergence was shown when the momentum term was zero. The MSPS uses a momentum term in order to speed up its convergence. The momentum term is built on the multiplication of a momentum parameter and the direction of the previous iterate. In this work, we show convergence when the momentum parameter is a non-zero constant. We also propose heuristics to choose the momentum parameter intended to avoid the Zigzagging Phenomenon of Kind I. This phenomenon is present in the MSPS when at an iterate the subgradient forms an obtuse angle with the previous direction. We identify and diminish the Zigzagging Phenomenon of Kind I on Setcovering problems, and compare our numerical results to those of the original MSPS algorithm.

  18. On subgradient projectors

    OpenAIRE

    Bauschke, Heinz H.; Wang, Caifang; Wang, Xianfu; Xu, Jia

    2014-01-01

    The subgradient projector is of considerable importance in convex optimization because it plays the key role in Polyak's seminal work - and the many papers it spawned - on subgradient projection algorithms for solving convex feasibility problems. In this paper, we offer a systematic study of the subgradient projector. Fundamental properties such as continuity, nonexpansiveness, and monotonicity are investigated. We also discuss the Yamagishi-Yamada operator. Numerous examples illustrate our r...

  19. Subgradient Projection Operators

    OpenAIRE

    Pauwels, Benoit

    2014-01-01

    Several algebraic and topological properties of subgradient projection operators are investigated and various examples are provided. Connections with Moreau's proximity operator are also made and acceleration schemes for subgradient projection algorihms are discussed. Finally continuity, nonexpansiveness, monotonicity, differentiability, and epi-convergence properties are investigated.

  20. A fast subgradient algorithm in image super-resolution

    Science.gov (United States)

    Lazzaro, D.; Loli Piccolomini, E.; Ruggiero, V.; Zama, F.

    2017-10-01

    In this paper we propose an ε–subgradient method for solving a constrained minimization problem arising in super-resolution imaging applications. The method, compared to the state-of-the-art methods for single image super-resolution on some test problems, proves to be very efficient, both for the reconstruction quality and the computational time.

  1. Privacy Preservation in Distributed Subgradient Optimization Algorithms.

    Science.gov (United States)

    Lou, Youcheng; Yu, Lean; Wang, Shouyang; Yi, Peng

    2017-07-31

    In this paper, some privacy-preserving features for distributed subgradient optimization algorithms are considered. Most of the existing distributed algorithms focus mainly on the algorithm design and convergence analysis, but not the protection of agents' privacy. Privacy is becoming an increasingly important issue in applications involving sensitive information. In this paper, we first show that the distributed subgradient synchronous homogeneous-stepsize algorithm is not privacy preserving in the sense that the malicious agent can asymptotically discover other agents' subgradients by transmitting untrue estimates to its neighbors. Then a distributed subgradient asynchronous heterogeneous-stepsize projection algorithm is proposed and accordingly its convergence and optimality is established. In contrast to the synchronous homogeneous-stepsize algorithm, in the new algorithm agents make their optimization updates asynchronously with heterogeneous stepsizes. The introduced two mechanisms of projection operation and asynchronous heterogeneous-stepsize optimization can guarantee that agents' privacy can be effectively protected.

  2. ɛ-subgradient algorithms for bilevel convex optimization

    Science.gov (United States)

    Helou, Elias S.; Simões, Lucas E. A.

    2017-05-01

    This paper introduces and studies the convergence properties of a new class of explicit ɛ-subgradient methods for the task of minimizing a convex function over a set of minimizers of another convex minimization problem. The general algorithm specializes to some important cases, such as first-order methods applied to a varying objective function, which have computationally cheap iterations. We present numerical experimentation concerning certain applications where the theoretical framework encompasses efficient algorithmic techniques, enabling the use of the resulting methods to solve very large practical problems arising in tomographic image reconstruction. ES Helou was supported by FAPESP grants 2013/07375-0 and 2013/16508-3 and CNPq grant 311476/2014-7. LEA Simões was supported by FAPESP grants 2011/02219-4 and 2013/14615-7.

  3. A conjugate subgradient algorithm with adaptive preconditioning for the least absolute shrinkage and selection operator minimization

    Science.gov (United States)

    Mirone, A.; Paleo, P.

    2017-04-01

    This paper describes a new efficient conjugate subgradient algorithm which minimizes a convex function containing a least squares fidelity term and an absolute value regularization term. This method is successfully applied to the inversion of ill-conditioned linear problems, in particular for computed tomography with the dictionary learning method. A comparison with other state-of-art methods shows a significant reduction of the number of iterations, which makes this algorithm appealing for practical use.

  4. A subgradient-based branch-and-bound algorithm for the capacitated facility location problem

    DEFF Research Database (Denmark)

    Görtz, Simon; Klose, Andreas

    This paper presents a simple branch-and-bound method based on Lagrangean relaxation and subgradient optimization for solving large instances of the capacitated facility location problem (CFLP) to optimality. In order to guess a primal solution to the Lagrangean dual, we average solutions to the L......This paper presents a simple branch-and-bound method based on Lagrangean relaxation and subgradient optimization for solving large instances of the capacitated facility location problem (CFLP) to optimality. In order to guess a primal solution to the Lagrangean dual, we average solutions...... to the Lagrangean subproblem. Branching decisions are then based on this estimated (fractional) primal solution. Extensive numerical results reveal that the method is much more faster and robust than other state-of-the-art methods for solving the CFLP exactly....

  5. String-averaging incremental subgradients for constrained convex optimization with applications to reconstruction of tomographic images

    Science.gov (United States)

    Massambone de Oliveira, Rafael; Salomão Helou, Elias; Fontoura Costa, Eduardo

    2016-11-01

    We present a method for non-smooth convex minimization which is based on subgradient directions and string-averaging techniques. In this approach, the set of available data is split into sequences (strings) and a given iterate is processed independently along each string, possibly in parallel, by an incremental subgradient method (ISM). The end-points of all strings are averaged to form the next iterate. The method is useful to solve sparse and large-scale non-smooth convex optimization problems, such as those arising in tomographic imaging. A convergence analysis is provided under realistic, standard conditions. Numerical tests are performed in a tomographic image reconstruction application, showing good performance for the convergence speed when measured as the decrease ratio of the objective function, in comparison to classical ISM.

  6. Perturbed projections and subgradient projections for the multiple-sets split feasibility problem

    Science.gov (United States)

    Censor, Yair; Motova, Avi; Segal, Alexander

    2007-03-01

    We study the multiple-sets split feasibility problem that requires to find a point closest to a family of closed convex sets in one space such that its image under a linear transformation will be closest to another family of closed convex sets in the image space. By casting the problem into an equivalent problem in a suitable product space we are able to present a simultaneous subgradients projections algorithm that generates convergent sequences of iterates in the feasible case. We further derive and analyze a perturbed projection method for the multiple-sets split feasibility problem and, additionally, furnish alternative proofs to two known results.

  7. Apparatus and methods for purifying lead

    Science.gov (United States)

    Tunison, Harmon M.

    2016-01-12

    Disclosed is an exemplary method of purifying lead which includes the steps of placing lead and a fluoride salt blend in a container; forming a first fluid of molten lead at a first temperature; forming a second fluid of the molten fluoride salt blend at a second temperature higher than the first temperature; mixing the first fluid and the second fluid together; separating the two fluids; solidifying the molten fluoride salt blend at a temperature above a melting point of the lead; and removing the molten lead from the container. In certain exemplary methods the molten lead is removed from the container by decanting. In still other exemplary methods the molten salt blend is a Lewis base fluoride eutectic salt blend, and in yet other exemplary methods the molten salt blend contains sodium fluoride, lithium fluoride, and potassium fluoride.

  8. A piecewise monotone subgradient algorithm for accurate L¹-TV based registration of physical slices with discontinuities in microscopy.

    Science.gov (United States)

    Michalek, Jan; Capek, Martin

    2013-05-01

    Image registration tasks are often formulated in terms of minimization of a functional consisting of a data fidelity term penalizing the mismatch between the reference and the target image, and a term enforcing smoothness of shift between neighboring pairs of pixels (a min-sum problem). Most methods for deformable image registration use some form of interpolation between matching control points. The interpolation makes it impossible to account for isolated discontinuities in the deformation field that may appear, e.g., when a physical slice of a microscopy specimen is ruptured by the cutting tool. For registration of neighboring physical slices of microscopy specimens with discontinuities, Janácek proposed an L¹-distance data fidelity term and a total variation (TV) smoothness term, and used a graph-cut (GC) based iterative steepest descent algorithm for minimization. The L¹-TV functional is nonconvex; hence a steepest descent algorithm is not guaranteed to converge to the global minimum. Schlesinger presented transformation of max-sum problems to minimization of a dual quantity called problem power, which is--contrary to the original max-sum functional--convex. Based on Schlesinger's solution to max-sum problems we developed an algorithm for L¹-TV minimization by iterative multi-label steepest descent minimization of the convex dual problem. For Schlesinger's subgradient algorithm we proposed a novel step control heuristics that considerably enhances both speed and accuracy compared with standard step size strategies for subgradient methods. It is shown experimentally that our subgradient scheme achieves consistently better image registration than GC in terms of lower values both of the composite L¹-TV functional, and of its components, i.e., the L¹ distance of the images and the transformation smoothness TV, and yields visually acceptable results even in cases where the GC based algorithm fails. The new algorithm allows easy parallelization and can thus be

  9. Subgradient-based neural networks for nonsmooth nonconvex optimization problems.

    Science.gov (United States)

    Bian, Wei; Xue, Xiaoping

    2009-06-01

    This paper presents a subgradient-based neural network to solve a nonsmooth nonconvex optimization problem with a nonsmooth nonconvex objective function, a class of affine equality constraints, and a class of nonsmooth convex inequality constraints. The proposed neural network is modeled with a differential inclusion. Under a suitable assumption on the constraint set and a proper assumption on the objective function, it is proved that for a sufficiently large penalty parameter, there exists a unique global solution to the neural network and the trajectory of the network can reach the feasible region in finite time and stay there thereafter. It is proved that the trajectory of the neural network converges to the set which consists of the equilibrium points of the neural network, and coincides with the set which consists of the critical points of the objective function in the feasible region. A condition is given to ensure the convergence to the equilibrium point set in finite time. Moreover, under suitable assumptions, the coincidence between the solution to the differential inclusion and the "slow solution" of it is also proved. Furthermore, three typical examples are given to present the effectiveness of the theoretic results obtained in this paper and the good performance of the proposed neural network.

  10. A subgradient approach for constrained binary optimization via quantum adiabatic evolution

    Science.gov (United States)

    Karimi, Sahar; Ronagh, Pooya

    2017-08-01

    Outer approximation method has been proposed for solving the Lagrangian dual of a constrained binary quadratic programming problem via quantum adiabatic evolution in the literature. This should be an efficient prescription for solving the Lagrangian dual problem in the presence of an ideally noise-free quantum adiabatic system. However, current implementations of quantum annealing systems demand methods that are efficient at handling possible sources of noise. In this paper, we consider a subgradient method for finding an optimal primal-dual pair for the Lagrangian dual of a constrained binary polynomial programming problem. We then study the quadratic stable set (QSS) problem as a case study. We see that this method applied to the QSS problem can be viewed as an instance-dependent penalty-term approach that avoids large penalty coefficients. Finally, we report our experimental results of using the D-Wave 2X quantum annealer and conclude that our approach helps this quantum processor to succeed more often in solving these problems compared to the usual penalty-term approaches.

  11. A novel subgradient-based optimization algorithm for blockmodel functional module identification.

    Science.gov (United States)

    Wang, Yijie; Qian, Xiaoning

    2013-01-01

    Functional module identification in biological networks may provide new insights into the complex interactions among biomolecules for a better understanding of cellular functional organization. Most of existing functional module identification methods are based on the optimization of network modularity and cluster networks into groups of nodes within which there are a higher-than-expectation number of edges. However, module identification simply based on this topological criterion may not discover certain kinds of biologically meaningful modules within which nodes are sparsely connected but have similar interaction patterns with the rest of the network. In order to unearth more biologically meaningful functional modules, we propose a novel efficient convex programming algorithm based on the subgradient method with heuristic path generation to solve the problem in a recently proposed framework of blockmodel module identification. We have implemented our algorithm for large-scale protein-protein interaction (PPI) networks, including Saccharomyces cerevisia and Homo sapien PPI networks collected from the Database of Interaction Proteins (DIP) and Human Protein Reference Database (HPRD). Our experimental results have shown that our algorithm achieves comparable network clustering performance in comparison to the more time-consuming simulated annealing (SA) optimization. Furthermore, preliminary results for identifying fine-grained functional modules in both biological networks and the comparison with the commonly adopted Markov Clustering (MCL) algorithm have demonstrated the potential of our algorithm to discover new types of modules, within which proteins are sparsely connected but with significantly enriched biological functionalities.

  12. Proximal subgradient and a characterization of Lipschitz function on Riemannian manifolds

    Science.gov (United States)

    Ferreira, Orizon P.

    2006-01-01

    A characterization of Lipschitz behavior of functions defined on Riemannian manifolds is given in this paper. First, it is extended the concept of proximal subgradient and some results of proximal analysis from Hilbert space to Riemannian manifold setting. A technique introduced by Clarke, Stern and Wolenski [F.H. Clarke, R.J. Stern, P.R. Wolenski, Subgradient criteria for monotonicity, the Lipschitz condition, and convexity, Canad. J. Math. 45 (1993) 1167-1183], for generating proximal subgradients of functions defined on a Hilbert spaces, is also extended to Riemannian manifolds in order to provide that characterization. A number of examples of Lipschitz functions are presented so as to show that the Lipschitz behavior of functions defined on Riemannian manifolds depends on the Riemannian metric.

  13. The Matrix Element Method at Next-to-Leading Order

    OpenAIRE

    Campbell, John M.; Giele, Walter T.; Williams, Ciaran

    2012-01-01

    This paper presents an extension of the matrix element method to next-to-leading order in perturbation theory. To accomplish this we have developed a method to calculate next-to-leading order weights on an event-by-event basis. This allows for the definition of next-to-leading order likelihoods in exactly the same fashion as at leading order, thus extending the matrix element method to next-to-leading order. A welcome by-product of the method is the straightforward and efficient generation of...

  14. The matrix element method at next-to-leading order

    Science.gov (United States)

    Campbell, John M.; Giele, Walter T.; Williams, Ciaran

    2012-11-01

    This paper presents an extension of the matrix element method to next-to-leading order in perturbation theory, for electro-weak final states. To accomplish this we have developed a method to calculate next-to-leading order weights on an event-by-event basis. This allows for the definition of next-to-leading order likelihoods in exactly the same fashion as at leading order, thus extending the matrix element method to next-to-leading order. A welcome by-product of the method is the straightforward and efficient generation of unweighted next-to-leading order events. As examples of the application of our next-to-leading order matrix element method we consider the measurement of the mass of the Z boson and also the search for the Higgs boson in the four lepton channel.

  15. Adaptive learning in complex reproducing kernel Hilbert spaces employing Wirtinger's subgradients.

    Science.gov (United States)

    Bouboulis, Pantelis; Slavakis, Konstantinos; Theodoridis, Sergios

    2012-03-01

    This paper presents a wide framework for non-linear online supervised learning tasks in the context of complex valued signal processing. The (complex) input data are mapped into a complex reproducing kernel Hilbert space (RKHS), where the learning phase is taking place. Both pure complex kernels and real kernels (via the complexification trick) can be employed. Moreover, any convex, continuous and not necessarily differentiable function can be used to measure the loss between the output of the specific system and the desired response. The only requirement is the subgradient of the adopted loss function to be available in an analytic form. In order to derive analytically the subgradients, the principles of the (recently developed) Wirtinger's calculus in complex RKHS are exploited. Furthermore, both linear and widely linear (in RKHS) estimation filters are considered. To cope with the problem of increasing memory requirements, which is present in almost all online schemes in RKHS, the sparsification scheme, based on projection onto closed balls, has been adopted. We demonstrate the effectiveness of the proposed framework in a non-linear channel identification task, a non-linear channel equalization problem and a quadrature phase shift keying equalization scheme, using both circular and non circular synthetic signal sources.

  16. Rapid new methods for paint collection and lead extraction.

    Science.gov (United States)

    Gutknecht, William F; Harper, Sharon L; Winstead, Wayne; Sorrell, Kristen; Binstock, David A; Salmons, Cynthia A; Haas, Curtis; McCombs, Michelle; Studabaker, William; Wall, Constance V; Moore, Curtis

    2009-01-01

    Chronic exposure of children to lead can result in permanent physiological impairment. In adults, it can cause irritability, poor muscle coordination, and nerve damage to the sense organs and nerves controlling the body. Surfaces coated with lead-containing paints are potential sources of exposure to lead. In April 2008, the U.S. Environmental Protection Agency (EPA) finalized new requirements that would reduce exposure to lead hazards created by renovation, repair, and painting activities, which disturb lead-based paint. On-site, inexpensive identification of lead-based paint is required. Two steps have been taken to meet this challenge. First, this paper presents a new, highly efficient method for paint collection that is based on the use of a modified wood drill bit. Second, this paper presents a novel, one-step approach for quantitatively grinding and extracting lead from paint samples for subsequent lead determination. This latter method is based on the use of a high-revolutions per minute rotor with stator to break up the paint into approximately 50 micron-size particles. Nitric acid (25%, v/v) is used to extract the lead in 95% for real-world paints, National Institute of Standards and Technology's standard reference materials, and audit samples from the American Industrial Hygiene Association's Environmental Lead Proficiency Analytical Testing Program. This quantitative extraction procedure, when paired with quantitative paint sample collection and lead determination, may enable the development of a lead paint test kit that will meet the specifications of the final EPA rule.

  17. Consensus-based distributed optimisation of multi-agent networks via a two level subgradient-proximal algorithm

    Science.gov (United States)

    Hu, Bin; Guan, Zhi-Hong; Liao, Rui-Quan; Zhang, Ding-Xue; Zheng, Gui-Lin

    2015-05-01

    This paper presents a consensus-based stochastic subgradient algorithm for multi-agent networks to minimise multiple convex but not necessarily differential objective functions, subject to an intersection set of multiple closed convex constraint sets. Compared with the existing results an alternative subgradient algorithm is first introduced based on two level subgradient iterations, where the first level is to minimise the component functions, and the second to enforce the iterates not oscillate from the constraint set wildly. In addition, a distributed consensus-based type of the proposed subgradient algorithm is constructed within the framework of multi-agent networks for the case when the iteration index of local objective functions and local constraint sets is not homologous. Detailed convergence analysis of the proposed algorithms is established using matrix theories and super-martingale convergence theorem. In addition, a pre-step convergence factor is obtained in this study to characterise the distance between the iterations and the optimal set, while some existing literatures only present a convergence work. Simulation results are given to demonstrate the effectiveness of the developed theoretical results.

  18. Duality problem for multi-objective fractional programming problems using the two concepts (dual space and subgradient

    Directory of Open Access Journals (Sweden)

    Ebrahim Youness

    1993-11-01

    Full Text Available The problem dual to a multi-objective fractional programming problems is defined by using the concept of dual space of the objective space and using the concept of subgradient. Some assumptions considered in recent works are relaxed in our proposed approach.

  19. Growth of lead molybdate crystals by vertical Bridgman method

    Indian Academy of Sciences (India)

    Unknown

    Crystal growth; Bridgman method; acousto-optic crystal; lead molybdate. 1. Introduction. Lead molybdate (PbMoO4, PMO) crystal is well known as an acousto-optic material with excellent properties such as higher acoustic–optic figure of merit and lower acoustic loss (Pinnow 1969). The crystal has attracted much interest for ...

  20. Auxiliary health diagnosis method for lead-acid battery

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yu-Hua; Jou, Hurng-Liahng; Wu, Kuen-Der [Department of Electrical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782 (China); Wu, Jinn-Chang [Department of Microelectronic Engineering, National Kaohsiung Marine University, 142, Haijhuan Road, Nanzih District, Kaohsiung 81143 (China)

    2010-12-15

    This paper proposes a health auxiliary diagnosis method for the lead-acid battery unit. The proposed method is based on Approximate Entropy (ApEn). Since ApEn can quantify the regularity of a data sequence and the discharging curve for a health lead-acid battery unit is smooth, the proposed method can detect the degradation of battery unit caused by the internal short, opening of internal shorted or cell undergoing reversal using the distorted discharging curve. Aging experiments for the lead-acid battery are developed to verify the proposed method. The experimental results verify that the proposed health auxiliary diagnosis method can diagnosis the degradation of battery unit caused by the internal short, opening of internal shorted or cell undergoing reversal. (author)

  1. An Adaptive Primal-Dual Subgradient Algorithm for Online Distributed Constrained Optimization.

    Science.gov (United States)

    Yuan, Deming; Ho, Daniel W C; Jiang, Guo-Ping

    2017-10-05

    In this paper, we consider the problem of solving distributed constrained optimization over a multiagent network that consists of multiple interacting nodes in online setting, where the objective functions of nodes are time-varying and the constraint set is characterized by an inequality. Through introducing a regularized convex-concave function, we present a consensus-based adaptive primal-dual subgradient algorithm that removes the need for knowing the total number of iterations T in advance. We show that the proposed algorithm attains an $O (T1/2 + c) [where c∈(0,1/2)] regret bound and an O (T1 - c/2) bound on the violation of constraints; in addition, we show an improvement to an $O (Tc) regret bound when the objective functions are strongly convex. The proposed algorithm allows a novel tradeoffs between the regret and the violation of constraints. Finally, a numerical example is provided to illustrate the effectiveness of the algorithm.

  2. Distributed Constrained Stochastic Subgradient Algorithms Based on Random Projection and Asynchronous Broadcast over Networks

    Directory of Open Access Journals (Sweden)

    Junlong Zhu

    2017-01-01

    Full Text Available We consider a distributed constrained optimization problem over a time-varying network, where each agent only knows its own cost functions and its constraint set. However, the local constraint set may not be known in advance or consists of huge number of components in some applications. To deal with such cases, we propose a distributed stochastic subgradient algorithm over time-varying networks, where the estimate of each agent projects onto its constraint set by using random projection technique and the implement of information exchange between agents by employing asynchronous broadcast communication protocol. We show that our proposed algorithm is convergent with probability 1 by choosing suitable learning rate. For constant learning rate, we obtain an error bound, which is defined as the expected distance between the estimates of agent and the optimal solution. We also establish an asymptotic upper bound between the global objective function value at the average of the estimates and the optimal value.

  3. Generalizations of the Alternating Direction Method of Multipliers for Large-Scale and Distributed Optimization

    Science.gov (United States)

    2014-05-01

    closely related to the dual ascent method (or dual subgradient method) [53] as well as the quadratic penalty method. Compared to these methods, the...t)y) ≤ tf(x) + (1− t)f(y)− 1 2 νt(1− t)‖x− y‖2. (2.28) For a convex function f , we let the subdifferential (i.e., the set of all subgradients ) of f...review A simple distributed algorithm for solving (5.1) is dual decomposition [19], which is essentially a dual ascent method or dual subgradient

  4. Dithizone method for determination of lead in monazite

    Science.gov (United States)

    Powell, R.A.; Kinser, C.A.

    1958-01-01

    In the determination of lead in monazite-to be used as the basis for geologic age measurements-it was necessary to eliminate interferences due to the presence of phosphates of thorium and the rare earth metals. The method involves attacking the monazite samples with hot, concentrated sulfuric acid, then taking them up with dilute nitric acid. Lead is extracted as the dithizonate and determined spectrophotometrically at 520 m??. Rapid determinations were made with good reproducibility on a series of monazite samples.

  5. Towards a novel design method for impact on leading edges

    NARCIS (Netherlands)

    van Houten, M.H.; Kaplan, H.

    2006-01-01

    Results of a parametric study concerning low velocity impact on leading edge profiles is presented. This work is the first part of a larger program on the development of an engineering design method for impact on Glare. In this first part, experimental tests and numerical simulations on

  6. A dithizone method for the determination of lead in monazite

    Science.gov (United States)

    Powell, R.A.; Kinser, C.A.

    1956-01-01

    In determining lead in monazite [(Ce,La,Th)PO4]--to be used as the basis for geologic age measurements--it was necessary to eliminate interferences due to the presences of phosphates of thorium and the rare-earth metals. The method, in which monazite samples are attacked with hot concentrated sulfuric acid, taken up with dilute nitric acid, lead extracted as the dithizonate and then determined spectrophotometrically at 520 mμ, was successfully applied to a series of monazite samples. Rapid determinations were made with good reproducibility.

  7. Lead

    Science.gov (United States)

    ... is serious about making sure companies that break the law are held accountable In the past year, EPA ... the health effects of lead in drinking water The law mandates no-lead products for drinking water after ...

  8. A new electrode placement method for obtaining 12-lead ECGs.

    Science.gov (United States)

    Khan, Gabriel M

    2015-01-01

    Worldwide, more than 50 million ECGs are carried out annually. Studies show that the standard wrist-ankle placement method may produce poor quality ECGs. Factors including limb movement, tremor, anxiety, cold extremities cause artefacts (distortions of the baseline and ECG waveforms). A problem exists. Physicians face a challenge interpreting poor quality ECGs. Diagnostic delays occur. Patients are subjected to recalls; compassion initiated this study. Torso (modified) leads are favoured as they provide rapid acquisition of better quality ECGs, but cause erroneous electrocardiography. Investigators have not attempted to correct these errors. This study analyses the errors and aims to rectify them. Our pilot and other studies indicated that torso electrodes placed close to the heart cause an increase in R wave amplitude >3 mm in inferior leads that results in disappearance of inferior infarcts; a decrease >3 mm in 1 and aVL may cause false lateral infarcts. We hypothesised that finding electrode placements that do not cause alterations in R wave amplitude should correct these problems. Several electrode placements were assessed to obtain ECGs identical with the standard, but with better quality. A total of 1112 patients received standard and new electrode placement recordings. ECG parameters were assessed. A blinded interpreter assisted. Electrodes positioned on the mid-arm and lower abdomen revealed ECGs identical with the standard without artefacts or loss of inferior or appearance of lateral infarcts. This study proved that the new method is faultless and provides better quality ECGs, no recalls and without risk for misinterpretations. Not having to remove leg garments is convenient and allows more rapid acquisition of ECGs. The forearms are freed for, intravenous, radial access, and ECGs needed during procedures. The findings have implications worldwide for patients, clinicians and technicians, and generate the need to study the method in emergency settings.

  9. Lead

    Science.gov (United States)

    ... Test Safety Alert: Learn about CDC Recommendations Second Informational Call (CDC-RFA-17-1701PPHF17), April 5, 2017, ... CLPPP CAP Healthy Homes Assessment Tools Lead Health Literacy Initiative Refugee Tool Kit Resources Healthy Homes and ...

  10. Research of lead extract method from accumulator scrap

    Directory of Open Access Journals (Sweden)

    Віктор Юрійович Кушнеров

    2016-12-01

    Full Text Available The analysis of production and consumption of lead from primary and secondary raw material is executed. It is determined that approximately 56 % general world lead production consists of lead-content secondary raw material processing – scrap and wastes of lead and accumulator scrap. Using thermodynamic analysis, it is determined that potassium bicarbonate has an advantage at processing of sulfate constituent of secondary raw material

  11. An Efficient Augmented Lagrangian Method with Applications to Total Variation Minimization

    Science.gov (United States)

    2012-08-17

    direction dk = −∂1φ(xk, y(xk)) can be regarded as a subgradient direction for ψ(x). However, since we do not require that y(x) be sub-differentiable, a...where we do not assume any differentiability of y(x). As such, NADA is no longer a standard gradient or subgradient method previously studied in

  12. Quantum confinement of lead titanate nanocrystals by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)

    2015-11-15

    Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.

  13. 2010 Lead (Pb) Air Monitoring Requirements & 2013 Method for Determination of Lead (Pb) in Total Suspended Particulate Matter Fact Sheets

    Science.gov (United States)

    This page contains a variety of fact sheets and other documents that are supplementary to the 2010 final revisions to lead (Pb) ambient air monitoring requirements and the 2013 final method for determination of Pb in total suspended particulate matter.

  14. Rapid New Methods for Paint Collection and Lead Extraction

    Science.gov (United States)

    Chronic exposure of children to lead (Ph) can result in permanent physiologic impairment. In adults, it can cause irritability, poor muscle coordination, and nerve damage to the sense organs and nerves controlling the body. Surfaces coated with Pb-containing paints are potential ...

  15. Tentative test method for lead in the atmosphere by colorimetric dithizone procedure

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    This method covers the determination of low levels of atmospheric lead. It involves separate measurements of particulate lead and vaporous lead. For the purpose of this method particulate lead is that collected on an efficient filter. Vaporous lead is that which will pass through a 0.45-..mu..m membrane filter or its equivalent and includes various tetra alkyl lead compounds or their partially decomposed products, or both.

  16. A simple lead dust fall method predicts children's blood lead level: New evidence from Australia.

    Science.gov (United States)

    Gulson, Brian; Taylor, Alan

    2017-11-01

    We have measured dust fall accumulation in petri dishes (PDD) collected 6 monthly from inside residences in Sydney urban area, New South Wales, Australia as part of a 5-year longitudinal study to determine environmental associations, including soil. with blood lead (PbB) levels. The Pb loading in the dishes (n = 706) had geometric means (GM) of 24µg/m 2 /30d, a median value of 22µg/m 2 /30d with a range from 0.2 to 11,390µg/m 2 /30d. Observed geometric mean PbB was 2.4µg/dL at ages 2-3 years. Regression analyses showed a statistically significant relationship between predicted PbB and PDD. The predicted PbB values from dust in our study are consistent with similar analyses from the US in which floor dust was collected by wipes. Predicted PbB values from PDD indicate that an increase in PDD of about 100µg/m 2 /30d would increase PbB by about 1.5µg/dL or a doubling PbB at the low levels currently observed in many countries. Predicted PbB values from soil indicate that a change from 0 to 1000mg Pb/kg results in an increase of 1.7µg/dL in PbB, consistent with earlier investigations. Blood Pb levels can be predicted from dust fall accumulation (and soil) in cases where blood sampling is not always possible, especially in young children. Petri dish loading data could provide an alternative or complementary "action level" at about 100µg Pb/m 2 /30 days, similar to the suggested level of about 110µg Pb/m 2 for surface wipes, for use in monitoring activities such as housing rehabilitation, demolition or soil resuspension. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Different partial volume correction methods lead to different conclusions

    DEFF Research Database (Denmark)

    Greve, Douglas N; Salat, David H; Bowen, Spencer L

    2016-01-01

    A cross-sectional group study of the effects of aging on brain metabolism as measured with (18)F-FDG-PET was performed using several different partial volume correction (PVC) methods: no correction (NoPVC), Meltzer (MZ), Müller-Gärtner (MG), and the symmetric geometric transfer matrix (SGTM) using...... of cortical regions showing a decrease with age. Simulations showed that NoPVC had significant bias that made the age effect on metabolism appear to be much larger and more significant than it is. MZ was found to be the same as NoPVC for liberal brain masks; for conservative brain masks, MZ showed few areas...... a substantial loss in the power to detect age-related changes. This diversity of results reflects the literature on the metabolism of aging and suggests that extreme care should be taken when applying PVC or interpreting results that have been corrected for partial volume effects. Using the SGTM, significant...

  18. Tentative method of test for lead in the atmosphere by colorimetric dithizone procedure. [Dithizone: Spectrophotometrically

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    Determination of low levels of atmospheric lead with separate measurement of particulate lead and vaporous lead isdescribed. Particulate lead is collected on an efficiency filter, and vaporous lead is that which will pass through a 0.45 ..mu..m membrane filter or its equivalent and includes various tetra-alkyl lead compounds or their partially decomposed products, or both. After separation, the particulate lead sample is digested with nitric and perchloric acids, and the dissolved lead is determined by a colorimetric dithizone procedure. The lead passing through the 0.45 ..mu..m membrane filter is absorbed on activated carbon. The method is intended primarily for measuring weekly averages of vaporous lead in ambient air at concentrations below 0.5 ..mu..g/m/sup 3/ and particulate lead in air at concentrations of 0.01 to 10.0 ..mu..g/m/sup 3/. Interference with the dithizone complex are noted for Bi, Sn/sup 2 +/, Tl/sup +/, and In. Since volatile organic compounds of these metals are not normally found in ambient air or they are removed by filters, these elements do not generally interfere with the determination of vaporous lead. A double extraction carried out at a higher pH will eliminate these interferences from the determination of particulate lead. (BLM)

  19. [Test method for lead in metal utensils for food contact use].

    Science.gov (United States)

    Mutsuga, Motoh; Yotsuyanagi, Michiyo; Kawamura, Yoko

    2011-01-01

    We compared test methods for measurement of lead in metal utensils using flame-atomic absorption spectroscopy (AAS), graphite furnace-AAS (GFAA), inductively coupled plasma atomic emission spectrometry (ICP) and X-ray fluorescence analysis (XRF). The procedure for preparation of the test solution was improved. A 100 mg of sample was dissolved in 2.5 mL of HCl and HNO(3) (3 : 1) mixture (in the case of titanium sample, dissolved in HCl). Stock solution was prepared by diluting to 50 mL with water. The test solution was prepared by diluting with 0.1 mol/L HNO(3). The recoveries of lead added to various kinds of metal reagent at the level of 0.1% were 90-118%. When standard materials which contained lead at the level of 0.0098-0.11% were measured, the measured values were in close agreement with the standard values. These procedures are applicable to aluminum, iron, stainless steel, copper, tin and titanium products. The AAS method, GFAA method and ICP method were suitable as the lead test methods. Moreover, the XRF method was useful as a screening method or a simple determination method. The ICP method was used to determine the lead contents in 22 kinds of commercial metal utensils, and 0.011-0.040% of lead were detected in 6 samples.

  20. Field turbidity method for the determination of lead in acid extracts of dried paint.

    Science.gov (United States)

    Studabaker, William B; McCombs, Michelle; Sorrell, Kristen; Salmons, Cynthia; Brown, G Gordon; Binstock, David; Gutknecht, William F; Harper, Sharon L

    2010-07-08

    Lead, which can be found in old paint, soil, and dust, has been clearly shown to have adverse health effects on the neurological systems of both children and adults. As part of an ongoing effort to reduce childhood lead poisoning, the US Environmental Protection Agency promulgated the Lead Renovation, Repair, and Painting Program (RRP) rule requiring that paint in target housing built prior to 1978 be tested for lead before any renovation, repair, or painting activities are initiated. This rule has led to a need for a rapid, relatively easy, and an inexpensive method for measuring lead in paint. This paper presents a new method for measuring lead extracted from paint that is based on turbidimetry. This method is applicable to paint that has been collected from a surface and extracted into 25% (v/v) of nitric acid. An aliquot of the filtered extract is mixed with an aliquot of solid potassium molybdate in 1 M ammonium acetate to form a turbid suspension of lead molybdate. The lead concentration is determined using a portable turbidity meter. This turbidimetric method has a response of approximately 0.9 NTU per microg lead per mL extract, with a range of 1-1000 Nephelometric Turbidity Units (NTUs). Precision at a concentration corresponding to the EPA-mandated decision point of 1 mg of lead per cm(2) is six reference materials with lead concentrations near 1 mg cm(-2) yielded a correlation to inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis of 0.97, with an average bias of 2.8%. Twenty-four sets of either 6 or 10 paint samples each were collected from different locations in old houses, a hospital, tobacco factory, and power station. Half of each set was analyzed using rotor/stator-25% (v/v) nitric acid extraction with measurement using the new turbidimetric method, and the other half was analyzed using microwave extraction and measurement by ICP-AES. The average relative percent difference between the turbidimetric method and the ICP

  1. Leading-edge force features of the aerodynamic finite element method.

    Science.gov (United States)

    Lan, C.-T.; Roskam, J.

    1972-01-01

    Description of a practical procedure for computing the wing leading-edge thrust distribution by the finite element method. When incorporated into a wing-body aerodynamic computer program, the technique is capable of predicting (at subsonic and supersonic speeds) the leading-edge thrust distribution (and therefore, the lateral-directional stability derivatives due to roll) and the nonlinear aerodynamic characteristics of low aspect-ratio wings with leading edge separation due to the application of suction technology.

  2. Standard test method for lead in the atmosphere by colorimetric dithizone procedure

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Determination of low levels of lead in the atmosphere using a very selective dithizone colorimetric procedures is described. Particulate lead (that collected on a 0.45-..mu..m membrane filter) and vaporous lead (that passing through the 0.45-..mu..m filter) are determined separately. The method as described is without interference from 20 ..mu..g of Bi, 10 ..mu..g of Tl(I), 100 ..mu..g of Sn(II), and 200 ..mu..g of In(III).

  3. Computational Methods Used in Hit-to-Lead and Lead Optimization Stages of Structure-Based Drug Discovery.

    Science.gov (United States)

    Heifetz, Alexander; Southey, Michelle; Morao, Inaki; Townsend-Nicholson, Andrea; Bodkin, Mike J

    2018-01-01

    GPCR modeling approaches are widely used in the hit-to-lead (H2L) and lead optimization (LO) stages of drug discovery. The aims of these modeling approaches are to predict the 3D structures of the receptor-ligand complexes, to explore the key interactions between the receptor and the ligand and to utilize these insights in the design of new molecules with improved binding, selectivity or other pharmacological properties. In this book chapter, we present a brief survey of key computational approaches integrated with hierarchical GPCR modeling protocol (HGMP) used in hit-to-lead (H2L) and in lead optimization (LO) stages of structure-based drug discovery (SBDD). We outline the differences in modeling strategies used in H2L and LO of SBDD and illustrate how these tools have been applied in three drug discovery projects.

  4. Comparison of methods for certification of stannic, stibium and lead traces in reference materials for steel

    Directory of Open Access Journals (Sweden)

    I. V. Khodakovskaya

    2016-01-01

    Full Text Available Development and introduction of new metallurgical technologies, new additional chemical compound indexes controlled in metallurgical materials demand to develop the new, more advanced methods of analytical control. The particular attention should be paid to identify the traces of stannic, stinium and lead because of their influence on metal characteristics.

  5. Overdiagnosis associated with breast cancer screening: A simulation study to compare lead-time adjustment methods.

    Science.gov (United States)

    Seigneurin, A; Labarère, J; Duffy, S W; Colonna, M

    2015-12-01

    Estimating overdiagnosis associated with breast cancer screening may use annual incidence rates of cancer. We simulated populations invited to screening programmes to assess two lead-time adjustment methods. Overdiagnosis estimates were computed using the compensatory drop method, which considered the decrease in incidence of cancers among older age groups no longer offered screening, and the method based on the decrease in incidence of late-stage cancers. The true value of overdiagnosis was 0% in all the data sets simulated. The compensatory drop method yielded an overdiagnosis estimate of -0.1% (95% credibility interval -0.5% to 0.5%) when participation rates among the population and risk of cancers were constant. However, if participation rates increased with calendar year as well as risk of cancer with birth cohorts, the overdiagnosis estimated was 11.0% (10.5-11.6%). Using the method based on the incidence of early- and late-stage cancers, overdiagnosis estimates were 8.9% (8.5-9.3%) and 17.6% (17.4-17.9%) when participation rates and risks of cancer were constant or increased with time, respectively. Adjustment for lead time based on the compensatory drop method is accurate only when participation rates and risks of cancer remain constant, whereas the adjustment method based on the incidence of early- and late-stage cancers results in overestimating overdiagnosis regardless of stability of participation rates and breast cancer risk. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. A fence barrier method of leading edge cell capture for explorative biochemical research.

    Science.gov (United States)

    Wager, Lucas J; Murray, Rachael Z; Thompson, Erik W; Leavesley, David I

    2017-09-03

    The scratch or wound-healing assay is used ubiquitously for investigating re-epithelialisation and has already revealed the importance of cells comprising the leading edge of healing epithelial wounds. However it is currently limited to studying the effect of known biochemical agents on the tissue of choice. Here we present an adaptation that extends the utility of this model to encompass the collection of cells from the leading edge of migrating epithelial sheets making available explorative biochemical analyses. The method is scalable and does not require expensive apparatus, making it suitable for large and small laboratories alike. We detail the application of our method and exemplify proof of principle data derived from primary human keratinocyte cultures.

  7. A New Method to Optimize the Wake Flow of a Vehicle: The Leading Edge Rotating Cylinder

    Directory of Open Access Journals (Sweden)

    Nan Shao

    2017-01-01

    Full Text Available The wake flow of a vehicle significantly influences its aerodynamic performance and the stability during high-speed drive. Therefore, optimization of the vehicle wake flow is an effective way to improve its aerodynamic performance and further improve the handling stability and fuel economy. In this paper, a new method, the leading edge rotating cylinder, is used to optimize the wake flow of a vehicle. According to the results of simulations, this method can reduce the pressure drag, increase the negative lift force, and strengthen the stability of the vehicle under crosswind. Furthermore, this method optimizes not only the wake flow of the vehicle with rotating cylinders but also the interactive vehicles in the driving route in overtaking maneuvers or platoon driving. In conclusion, this method effectively optimizes the flow fields around the vehicles, and it significantly helps to improve the handling stability and fuel economy of the vehicle.

  8. New real-time heartbeat detection method using the angle of a single-lead electrocardiogram.

    Science.gov (United States)

    Song, Mi-Hye; Cho, Sung-Pil; Kim, Wonky; Lee, Kyoung-Joung

    2015-04-01

    This study presents a new real-time heartbeat detection algorithm using the geometric angle between two consecutive samples of single-lead electrocardiogram (ECG) signals. The angle was adopted as a new index representing the slope of ECG signal. The method consists of three steps: elimination of high-frequency noise, calculation of the angle of ECG signal, and detection of R-waves using a simple adaptive thresholding technique. The MIT-BIH arrhythmia database, QT database, European ST-T database, T-wave alternans database and synthesized ECG signals were used to evaluate the performance of the proposed algorithm and compare with the results of other methods suggested in literature. The proposed method shows a high detection rate-99.95% of the sensitivity, 99.95% of the positive predictivity, and 0.10% of the fail detection rate on the four databases. The result shows that the proposed method can yield better or comparable performance than other literature despite the relatively simple process. The proposed algorithm needs only a single-lead ECG, and involves a simple and quick calculation. Moreover, it does not require post-processing to enhance the detection. Thus, it can be effectively applied to various real-time healthcare and medical devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Momentum measurement by the Multiple Coulomb Scattering method in the OPERA lead emulsion target

    CERN Document Server

    Agafonova, N.; Altinok, O.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Autiero, D.; Badertscher, A.; Bagulya, A.; Ben Dhahbi, A.; Bertolin, A.; Besnier, M.; Bozza, C.; Brugiere, T.; Brugnera, R.; Brunet, F.; Brunetti, G.; Buontempo, S.; Cazes, A.; Chaussard, L.; Chernyavskiy, M.; Chiarella, V.; Chukanov, A.; D'Ambrosio, N.; Dal Corso, F.; De Lellis, G.; del Amo Sanchez, P.; Declais, Y.; De Serio, M.; Di Capua, F.; Di Crescenzo, A.; Di Ferdinando, D.; Di Marco, N.; Dmitrievski, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Egorov, O.; Enikeev, R.; Ereditato, A.; Esposito, L.S.; Favier, J.; Ferber, T.; Fini, R.A.; Frekers, D.; Fukuda, T.; Garfagnini, A.; Giacomelli, G.; Giorgini, M.; Gollnitz, C.; Goldberg, J.; Golubkov, D.; Goncharova, L.; Gornushkin, Y.; Grella, G.; Grianti, F.; Guler, A.M.; Gustavino, C.; Hagner, C.; Hamada, K.; Hara, T.; Hierholzer, M.; Hollnagel, A.; Hoshino, K.; Ieva, M.; Ishida, H.; Jakovcic, K.; Jollet, C.; Juget, F.; Kamiscioglu, M.; Kazuyama, K.; Kim, S.H.; Kimura, M.; Kitagawa, N.; Klicek, B.; Knuesel, J.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Kubota, H.; Lazzaro, C.; Lenkeit, J.; Lippi, I.; Ljubicic, A.; Longhin, A.; Loverre, P.; Lutter, G.; Malgin, A.; Mandrioli, G.; Manai, K.; Marteau, J.; Matsuo, T.; Matveev, V.; Mauri, N.; Medinaceli, E.; Meisel, F.; Meregaglia, A.; Migliozzi, P.; Mikado, S.; Miyamoto, S.; Monacelli, P.; Morishima, K.; Moser, U.; Muciaccia, M.T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Naumov, D.; Nikitina, V.; Niwa, K.; Nonoyama, Y.; Ogawa, S.; Okateva, N.; Olshevskiy, A.; Paniccia, M.; Paoloni, A.; Park, B.D.; Park, I.G.; Pastore, A.; Patrizii, L.; Pennacchio, E.; Pessard, H.; Pretzl, K.; Pilipenko, V.; Pistillo, C.; Polukhina, N.; Pozzato, M.; Pupilli, F.; Rescigno, R.; Roganova, T.; Rokujo, H.; Romano, G.; Rosa, G.; Rostovtseva, I.; Rubbia, A.; Russo, A.; Ryasny, V.; Ryazhskaya, O.; Sato, O.; Sato, Y.; Schembri, A.; Schmidt-Parzefall, W.; Schroeder, H.; Scotto Lavina, L.; Sheshukov, A.; Shibuya, H.; Shoziyoev, G.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Song, J.S.; Spinetti, M.; Stanco, L.; Starkov, N.; Stipcevic, M.; Strauss, T.; Strolin, P.; Takahashi, S.; Tenti, M.; Terranova, F.; Tezuka, I.; Tioukov, V.; Tolun, P.; Trabelsi, A.; Tran, T.; Tufanli, S.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J.L.; Wilquet, G.; Wonsak, B.; Yakushev, V.; Yoon, C.S.; Yoshioka, T.; Yoshida, J.; Zaitsev, Y.; Zemskova, S.; Zghiche, A.; Zimmermann, R.

    2012-01-01

    A new method of momentum measurement of charged particles through Multiple Coulomb Scattering (MCS) in the OPERA lead emulsion target is presented. It is based on precise measurements of track angular deviations performed thanks to the very high resolution of nuclear emulsions. The algorithm has been tested with Monte Carlo (MC) pions. The results are found to describe within the expected uncertainties the data obtained from test beams. We also report a comparison of muon momenta evaluated through MCS in the OPERA lead emulsion target with those determined by the electronic detectors for neutrino charged current interaction events. The two independent measurements agree within the experimental uncertainties, and the results validate the algorithm developed for the emulsion detector of OPERA.

  10. Gap energy studied by optical transmittance in lead iodide monocrystals grown by Bridgman's Method

    Directory of Open Access Journals (Sweden)

    Veissid N.

    1999-01-01

    Full Text Available The bandgap energy as a function of temperature has been determined for lead iodide. The monocrystal was obtained in a vacuum sealed quartz ampoule inside a vertical furnace by Bridgman's method. The optical transmittance measurement enables to evaluate the values of Eg. By a fitting procedure of Eg as a function of temperature is possible to extract the parameters that govern its behavior. The variation of Eg with temperature was determined as: Eg(T = Eg(0 - aT2/(a + T, with: Eg(0 = (2.435 ± 0.008 eV, a = (8.7 ± 1.3 x 10-4 eV/K and a = (192 ± 90 K. The bandgap energy of lead iodide at room temperature was found to be 2.277 ± 0.007 eV.

  11. Simple determination of sulfate ion in rain by volumetric methods using lead (II) nitrate and dithizone

    Energy Technology Data Exchange (ETDEWEB)

    Gu Yongzuo; Zhou Qizhi (Sichuan Univ., Chengdu, SC (China)); Iwatsuki, M.; Fukasawa, T. (Yamanashi Univ., Yamanashi (Japan). Faculty of Engineering)

    1993-05-10

    Nowadays, 'acid rain' is one of serious problems in the world. Sulfate ion is one of main constituents in the acid rain, and its rapid and reliable determination is very important for the application to a lot of samples. For its determination, turbidimetry, spectrophotometry and ion chromatography are generally employed. In this paper, volumetric methods are proposed for simple determination of sulfate ion in rain. Lead (II) nitrate and dithizone are used as titrant and indicator, respectively, and the end point is determined either visually or photometrically. Recovery ratio of ions, precision, and effect of foreign ions on determination of sulfate ion by the methods were studied, and compared with those by the turbidimetry and ion chromatography. The proposed methods, especially the visual titration has advantages of simplicity, rapidity, and suitability for routine analysis, and requires no expensive equipment. 5 refs., 4 tabs.

  12. Study on Leading Vehicle Detection at Night Based on Multisensor and Image Enhancement Method

    Directory of Open Access Journals (Sweden)

    Mei Chen

    2016-01-01

    Full Text Available Low visibility is one of the reasons for rear accident at night. In this paper, we propose a method to detect the leading vehicle based on multisensor to decrease rear accidents at night. Then, we use image enhancement algorithm to improve the human vision. First, by millimeter wave radar to get the world coordinate of the preceding vehicles and establish the transformation of the relationship between the world coordinate and image pixels coordinate, we can convert the world coordinates of the radar target to image coordinate in order to form the region of interesting image. And then, by using the image processing method, we can reduce interference from the outside environment. Depending on D-S evidence theory, we can achieve a general value of reliability to test vehicles of interest. The experimental results show that the method can effectively eliminate the influence of illumination condition at night, accurately detect leading vehicles, and determine their location and accurate positioning. In order to improve nighttime driving, the driver shortage vision, reduce rear-end accident. Enhancing nighttime color image by three algorithms, a comparative study and evaluation by three algorithms are presented. The evaluation demonstrates that results after image enhancement satisfy the human visual habits.

  13. A novel method for direct solder bump pull testing using lead-free solders

    Science.gov (United States)

    Turner, Gregory Alan

    This thesis focuses on the design, fabrication, and evaluation of a new method for testing the adhesion strength of lead-free solders, named the Isotraction Bump Pull method (IBP). In order to develop a direct solder joint-strength testing method that did not require customization for different solder types, bump sizes, specific equipment, or trial-and-error, a combination of two widely used and accepted standards was created. First, solder bumps were made from three types of lead free solder were generated on untreated copper PCB substrates using an in-house fabricated solder bump-on-demand generator, Following this, the newly developed method made use of a polymer epoxy to encapsulate the solder bumps that could then be tested under tension using a high precision universal vertical load machine. The tests produced repeatable and predictable results for each of the three alloys tested that were in agreement with the relative behavior of the same alloys using other testing methods in the literature. The median peak stress at failure for the three solders tested were 2020.52 psi, 940.57 psi, and 2781.0 psi, and were within one standard deviation of the of all data collected for each solder. The assumptions in this work that brittle fracture occurred through the Intermetallic Compound layer (IMC) were validated with the use of Energy-Dispersive X-Ray Spectrometry and high magnification of the fractured surface of both newly exposed sides of the test specimens. Following this, an examination of the process to apply the results from the tensile tests into standard material science equations for the fracture of the systems was performed..

  14. Misuse of statistical methods in 10 leading Chinese medical journals in 1998 and 2008.

    Science.gov (United States)

    Wu, Shunquan; Jin, Zhichao; Wei, Xin; Gao, Qingbin; Lu, Jian; Ma, Xiuqiang; Wu, Cheng; He, Qian; Wu, Meijing; Wang, Rui; Xu, Jinfang; He, Jia

    2011-01-01

    Statistical methods are vital to biomedical research. Our aim was to find out whether progress has been made in the last decade in the use of statistical methods in Chinese medical research. We reviewed 10 leading Chinese medical journals published in 1998 and in 2008. Regarding statistical methods, using a multiple t-test for multiple group comparison was the most common error in the t-test in both years, which significantly decreased in 2008. In contingency tables, no significant level adjustment for multiple comparison significantly decreased in 2008. In ANOVA, over a quarter of articles misused the method of multiple pair-wise comparison in both years, and no significant difference was seen between the two years. In the rank transformation nonparametric test, the error of using multiple pair-wise comparison for multiple group comparison became less common. Many mistakes were found in the randomised controlled trial (56.3% in 1998; 67.9% in 2008), non- randomised clinical trial (57.3%; 58.6%), basic science study (72.9%; 65.5%), case study or case series study (48.4%; 47.2%), and cross-sectional study (57.1%; 44.2%). Progress has been made in the use of statistical methods in Chinese medical journals, but much is yet to be done.

  15. Automated method for tracing leading and trailing processes of migrating neurons in confocal image sequences

    Science.gov (United States)

    Kerekes, Ryan A.; Gleason, Shaun S.; Trivedi, Niraj; Solecki, David J.

    2010-03-01

    Segmentation, tracking, and tracing of neurons in video imagery are important steps in many neuronal migration studies and can be inaccurate and time-consuming when performed manually. In this paper, we present an automated method for tracing the leading and trailing processes of migrating neurons in time-lapse image stacks acquired with a confocal fluorescence microscope. In our approach, we first locate and track the soma of the cell of interest by smoothing each frame and tracking the local maxima through the sequence. We then trace the leading process in each frame by starting at the center of the soma and stepping repeatedly in the most likely direction of the leading process. This direction is found at each step by examining second derivatives of fluorescent intensity along curves of constant radius around the current point. Tracing terminates after a fixed number of steps or when fluorescent intensity drops below a fixed threshold. We evolve the resulting trace to form an improved trace that more closely follows the approximate centerline of the leading process. We apply a similar algorithm to the trailing process of the cell by starting the trace in the opposite direction. We demonstrate our algorithm on two time-lapse confocal video sequences of migrating cerebellar granule neurons (CGNs). We show that the automated traces closely approximate ground truth traces to within 1 or 2 pixels on average. Additionally, we compute line intensity profiles of fluorescence along the automated traces and quantitatively demonstrate their similarity to manually generated profiles in terms of fluorescence peak locations.

  16. Application of risk analysis and quality control methods for improvement of lead molding process

    Directory of Open Access Journals (Sweden)

    H. Gołaś

    2016-10-01

    Full Text Available The aim of the paper is to highlight the significance of implication of risk analysis and quality control methods for the improvement of parameters of lead molding process. For this reason, Fault Mode and Effect Analysis (FMEA was developed in the conceptual stage of a new product TC-G100-NR. However, the final product was faulty (a complete lack of adhesion of brass insert to leak regardless of the previously defined potential problem and its preventive action. It contributed to the recognition of root causes, corrective actions and change of production parameters. It showed how these methods, level of their organization, systematic and rigorous study affect molding process parameters.

  17. Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Sabah Shiri

    2011-01-01

    Full Text Available The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb 2+ ions and Alizarin yellow between aqueous and n -hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer's Law was obeyed over the concentration range of 3.86 × 10 -8 To 8.20 × 10 -7 molL -1 (8-170 ngmL -1 with an apparent molar absorptivity of 1.33 × 10 6 molL -1 cm -1 for a 100 mL aliquot of the water sample. The detection limit (n = 10 was 8.7 × 10 -9 molL -1 (1.0 ngmL -1 and the Relative standard deviation (R.S.D, (n = 10 for 7.2 × 10 -7 molL -1 (150 ngmL -1 of Pb (II was 4.36%. A notable advantage of the method is that the determination of Pb (II is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples.

  18. Determination of Trace Amounts of Lead Using the Flotation-spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Sabah Shiri

    2010-01-01

    Full Text Available The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb 2+ ions and Alizarin yellow between aqueous and n -hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared sea water samples. Beer's Law was obeyed over the concentration range of 3.86 × 10 −8 To 8.20 × 10 −7 molL −1 (8-170 ngmL −1 with an apparent molar absorptivity of 1.33 × 10 6 molL −1 cm −1 for a 100 mL aliquot of the water sample. The detection limit (n = 10 was 8.7 × 10 −9 molL −1 (1.0 ngmL −1 and the Relative standard deviation (R.S.D, (n = 10 for 7.2 × 10 −7 molL −1 (150 ngmL −1 of Pb (II was 4.36%. A notable advantage of the method is that the determination of Pb (II is free from the interference of almost all cations and ions found in the environment and waste water samples. The determination of Pb (II in tap and synthetic seawater samples was also carried out by the present method. The results were satisfactorily comparable so that the applicability of the proposed method was confirmed to the real samples.

  19. Comparison of methods for measuring atmospheric deposition of arsenic, cadmium, nickel and lead.

    Science.gov (United States)

    Aas, Wenche; Alleman, Laurent Y; Bieber, Elke; Gladtke, Dieter; Houdret, Jean-Luc; Karlsson, Vuokko; Monies, Christian

    2009-06-01

    A comprehensive field intercomparison at four different types of European sites (two rural, one urban and one industrial) comparing three different collectors (wet only, bulk and Bergerhoff samplers) was conducted in the framework of the European Committee for Standardization (CEN) to create an European standard for the deposition of the four elements As, Cd, Ni and Pb. The purpose was to determine whether the proposed methods lead to results within the uncertainty required by the EU's daughter directive (70%). The main conclusion is that a different sampling strategy is needed for rural and industrial sites. Thus, the conclusions on uncertainties and sample approach are presented separately for the different approaches. The wet only and bulk collector ("bulk bottle method") are comparable at wet rural sites where the total deposition arises mainly from precipitation, the expanded uncertainty when comparing these two types of sampler are below 45% for As, Cd and Pb, 67% for Ni. At industrial sites and possibly very dry rural and urban sites it is necessary to use Bergerhoff samplers or a "bulk bottle+funnel method". It is not possible to address the total deposition estimation with these methods, but they will give the lowest estimate of the total deposition. The expanded uncertainties when comparing the Bergerhoff and the bulk bottle+funnel methods are below 50% for As and Cd, and 63% for Pb. The uncertainty for Ni was not addressed since the bulk bottle+funnel method did not include a full digestion procedure which is necessary for sites with high loads of undissolved metals. The lowest estimate can however be calculated by comparing parallel Bergerhoff samplers where the expanded uncertainty for Ni was 24%. The reproducibility is comparable to the between sampler/method uncertainties. Sampling and sample preparation were proved to be the main factors in the uncertainty budget of deposition measurements.

  20. Analysis of Traffic Accidents Leading to Death Using Tripod Beta Method in Yazd, Iran

    Directory of Open Access Journals (Sweden)

    Mehrzad Ebrahemzadih

    2016-06-01

    Full Text Available This study tried to find the original causes of road accidents to prevent their occurrence. This was a descriptive-analytic retrospective study which assessed 1,000 cases of road accidents leading to death during 2003-2013 using the Tripod Beta method. The latent problems, the contributing preconditions, and corrective strategies for the prevention of occurrence of these accidents were determined. The findings of this study revealed that violation of traffic safety rules, especially deliberate violations and risk-takings decreased with increasing age. In comparative status of the superficial problems, illegal and impermissible speed of drivers accounted for 19.10%, in comparative status of preconditions, violation of safety rules accounted for 32.6% and finally, in comparative status of the latent problems, the presence of financial constraints and time pressure in designing and manufacturing of the cars, and quality of city streets, roads, accounted for 20.1%, of the leading causes of occurrence of accidents in this study.

  1. Lead Time and Overdiagnosis in Prostate-Specific Antigen Screening : Importance of Methods and Context

    NARCIS (Netherlands)

    Draisma, Gerrit; Etzioni, Ruth; Tsodikov, Alex; Mariotto, Angela; Wever, Elisabeth; Gulati, Roman; Feuer, Eric; de Koning, Harry

    2009-01-01

    Background The time by which prostate-specific antigen (PSA) screening advances prostate cancer diagnosis, called the lead time, has been reported by several studies, but results have varied widely, with mean lead times ranging from 3 to 12 years. A quantity that is closely linked with the lead time

  2. What is the best method of surgical training?: A report of America's leading senior surgeons.

    Science.gov (United States)

    Ko, C Y; Whang, E E; Karamanoukian, R; Longmire, W P; McFadden, D W

    1998-08-01

    To characterize the career choices and developments made by leading senior surgeons in this country and to examine hypothetically whether application of a short tracking program would have hindered their career decisions. A survey pertaining to each surgeon's career, decisions, and opinions concerning surgical training. Senior surgeons of regional and national surgical societies. Survey responses. A total of 352 surveys (41.4%) were received. Respondents answered that the most common reasons for choosing a specialty were role models or mentors (56%), research (51%), and available patient population (23%). The 2 most common stages in a career at which the respondents became interested in a specialty, or an area of expertise, were at the junior residency level (when the specialty was chosen) and at the assistant professor level (when a more specific topic within the specialty was chosen). The most common stage at which the group believed they acquired their expertise was also at the assistant professor level. Seventy-one percent of respondents believed broad training was superior to a short tracking system, although none had participated in shortened surgical training. Most leading senior surgeons in this country still believe that broad surgical training is superior and should be maintained. Because career specialties in this surveyed group were generally chosen in early residency, a hypothetical application of the short tracking system would have still allowed for these important decisions to be made. Also, it seems likely that specialty and career development would not have been hindered because "expertization" mostly occurred after training was completed. Regardless of training method, a role model or mentor seems most important in career choices and developments.

  3. A novel surface cleaning method for chemical removal of fouling lead layer from chromium surfaces

    Science.gov (United States)

    Gholivand, Kh.; Khosravi, M.; Hosseini, S. G.; Fathollahi, M.

    2010-10-01

    Most products especially metallic surfaces require cleaning treatment to remove surface contaminations that remain after processing or usage. Lead fouling is a general problem which arises from lead fouling on the chromium surfaces of bores and other interior parts of systems which have interaction with metallic lead in high temperatures and pressures. In this study, a novel chemical solution was introduced as a cleaner reagent for removing metallic lead pollution, as a fouling metal, from chromium surfaces. The cleaner aqueous solution contains hydrogen peroxide (H 2O 2) as oxidizing agent of lead layer on the chromium surface and acetic acid (CH 3COOH) as chelating agent of lead ions. The effect of some experimental parameters such as acetic acid concentration, hydrogen peroxide concentration and temperature of the cleaner solution during the operation on the efficiency of lead cleaning procedure was investigated. The results of scanning electron microscopy (SEM) showed that using this procedure, the lead pollution layer could be completely removed from real chromium surfaces without corrosion of the original surface. Finally, the optimum conditions for the complete and fast removing of lead pollution layer from chromium surfaces were proposed. The experimental results showed that at the optimum condition (acetic acid concentration 28% (V/V), hydrogen peroxide 8% (V/V) and temperature 35 °C), only 15-min time is needed for complete removal of 3 g fouling lead from a chromium surface.

  4. Time-Spectral Analysis Methods for Spent Fuel Assay Using Lead Slowing-Down Spectroscopy

    Science.gov (United States)

    Smith, L. Eric; Anderson, Kevin K.; Ressler, Jennifer J.; Shaver, Mark W.

    2010-08-01

    Nondestructive techniques for measuring the mass of fissile isotopes in spent nuclear fuel is a considerable challenge in the safeguarding of nuclear fuel cycles. A nondestructive assay technology that could provide direct measurement of fissile mass, particularly for the plutonium (Pu) isotopes, and improve upon the uncertainty of today's confirmatory methods is needed. Lead slowing-down spectroscopy (LSDS) has been studied for the spent fuel application previously, but the nonlinear effects of assembly self shielding (of the interrogating neutron population) have led to discouraging assay accuracy for realistic pressurized water reactor fuels. In this paper, we describe the development of time-spectral analysis algorithms for LSDS intended to overcome these self-shielding effects. The algorithm incorporates the tabulated energy-dependent cross sections from key fissile and absorbing isotopes, but leaves their mass as free variables. Multi-parameter regression analysis is then used to directly calculate not only the mass of fissile isotopes in the fuel assembly (e.g., Pu-239, U-235, and Pu-241), but also the mass of key absorbing isotopes such as Pu-240 and U-238. Modeling-based assay results using this self-shielding relationship indicate that LSDS has the potential to directly measure fissile isotopes with less than 5% average relative error for pressurized water reactor assemblies with burnup as high as 60 GWd/MTU. Shortcomings in the initial self-shielding model and potential improvements to the formulation are described.

  5. Field Turbidity Methods for the Determination of Lead in Acid Extracts of Dried Paint

    Science.gov (United States)

    Lead, which can be found in old paint, soil, and dust, has been clearly shown to have adverse health effects on the neurological systems of both children and adults. As part of an ongoing effort to reduce childhood lead poisoning, the U.S. Environmental Protection Agency promulga...

  6. Lead time and overdiagnosis in prostate-specific antigen screening: Importance of methods and context

    NARCIS (Netherlands)

    G. Draisma (Gerrit); R. Etzioni (Ruth); A. Tsodikov (Alex); A. Mariotto (Angela); E.M. Wever (Elisabeth); R. Gulati (Roman); E. Feuer (Eric); H.J. de Koning (Harry)

    2009-01-01

    textabstractBackground The time by which prostate-specific antigen (PSA) screening advances prostate cancer diagnosis, called the lead time, has been reported by several studies, but results have varied widely, with mean lead times ranging from 3 to 12 years. A quantity that is closely linked with

  7. Field methods for determining lead content in bridge paint removal waste.

    Science.gov (United States)

    2013-12-01

    The removal of paint from bridges and other structures is a significant issue facing transportation agencies because of the presence and : potential for release of lead and other contaminants upon disposal. A large percentage of the bridges are reach...

  8. Lead time and overdiagnosis in prostate-specific antigen screening: Importance of methods and context

    National Research Council Canada - National Science Library

    isma, Gerrit; Etzioni, Ruth; Tsodikov, Alex; Mariotto, Angela; Wever, Elisabeth; Gulati, Roman; Feuer, Eric; Koning, Harry

    2009-01-01

    .... A quantity that is closely linked with the lead time is the overdiagnosis frequency, which is the fraction of screen-detected cancers that would not have been diagnosed in the absence of screening...

  9. SHORT-TERM EXPOSURE OF FRESHWATER ALGAE TO LEAD ORGANIC COMPOUNDS STUDIED WITH NON-INVASIVE ELECTRICAL AND LUMINESCENT METHODS

    Directory of Open Access Journals (Sweden)

    Robert Borc

    2016-12-01

    Full Text Available In this paper the non-invasive biophysical methods were applied to assess the organic lead compounds absorption by freshwater algae Nitellopsis obtusa. Two biophysical techniques were used: the electrical method AC bridge with four external electrodes and the luminescent with the registration of ultraweak photon radiation emitted by plants. They allow to study the electrical and luminescent cell membrane properties. Research was performed with the lead acetate and trimethyl-lead chloride to verify whether algae cells were able to absorb Pb ions from water medium contaminated by these compounds. When the concentration of lead acetate solution increased up to 25 -100 µM the membrane resting potential changed from -140 mV to -175 mV. On the other hand, the electrical resistance of cell membrane (for 12-50 µM increased with exposure time exceeding its starting value up to 1.5 times. In contrast to these electrical changes, the intensity of ultraweak luminescence was constant at concentrations below 1 µM lead acetate. These results with comparison of literature data can suggest that there was no lipid peroxidation in cell membranes for such organic lead compound concentrations. Chemiluminescent responses of algae were observed in the first 5 hours of experiments for lead concentration higher than 1 µM. The luminescence intensity increased immediately for both reagents, but no more than 4 times for concentrations of 1-10 µM lead acetate. For tetramethyl-lead chloride, the luminescence intensity started to increase slowly about 40 minutes after injection. These results with comparison of literature data may suggest lipid peroxidation in cell membrane for higher, toxic lead concentrations. It means that higher concentrations of lead can trigger lethal processes in the living cells. We conclude that the return of the electrical and chemiluminescent plant parameters to the starting values (before the action of lead ions can indicate whether living

  10. The effect of different propolis harvest methods on its lead contents determined by ET AAS and UV-visS

    Energy Technology Data Exchange (ETDEWEB)

    Sales, A. [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina)]. E-mail: amsales@fbqf.unt.edu.ar; Alvarez, A. [National Institute of Agricultural Technology (INTA), Experimental Station Famailla, Ruta 301, Km 32, Famailla, Tucuman (Argentina); Areal, M. Rodriguez [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina); Maldonado, L. [National Institute of Agricultural Technology (INTA), Experimental Station Famailla, Ruta 301, Km 32, Famailla, Tucuman (Argentina); Marchisio, P. [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina); Rodriguez, M. [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina); Bedascarrasbure, E. [National Institute of Agricultural Technology (INTA), Experimental Station Famailla, Ruta 301, Km 32, Famailla, Tucuman (Argentina)

    2006-10-11

    Argentinean propolis is exported to different countries, specially Japan. The market demands propolis quality control according to international standards. The analytical determination of some metals, as lead in food, is very important for their high toxicity even in low concentrations and because of their harmful effects on health. Flavonoids, the main bioactive compounds of propolis, tend to chelate metals as lead, which becomes one of the main polluting agents of propolis. The lead found in propolis may come from the atmosphere or it may be incorporated in the harvest, extraction and processing methods. The aim of this work is to evaluate lead level on Argentinean propolis determined by electrothermal atomic absorption spectrometry (ET AAS) and UV-vis spectrophotometry (UV-visS) methods, as well as the effect of harvest methods on those contents. A randomized test with three different treatments of collection was made to evaluate the effect of harvest methods. These procedures were: separating wedges (traditional), netting plastic meshes and stamping out plastic meshes. By means of the analysis of variance technique for multiple comparisons (ANOVA) it was possible to conclude that there are significant differences between scraped and mesh methods (stamped out and mosquito netting meshes). The results obtained in the present test would allow us to conclude that mesh methods are more advisable than scraped ones in order to obtain innocuous and safe propolis with minor lead contents. A statistical comparison of lead determination by both, ET AAS and UV-visS methods, demonstrated that there is not a significant difference in the results achieved with the two analytical techniques employed.

  11. 40 CFR Appendix B to Part 80 - Test Methods for Lead in Gasoline

    Science.gov (United States)

    2010-07-01

    ... sample is diluted with methyl isobutyl ketone and the alkyl lead compounds are stabilized by reaction... reagent blank, adjust the gas mixture and the sample aspiration rate to obtain an oxidizing flame. 5.2.1... content. 7. Calculations. 7.1 Plot the absorbance values versus concentration represented by the working...

  12. Method of analysis for the determination of lead and cadmium in fresh meat

    NARCIS (Netherlands)

    Ruig, de W.G.

    1980-01-01

    This report comprises the result of the RIKILT of an intercomparison on the determination of lead and cadmium in bovine liver and bovine kidney. The aim of this round robbin was to check a wet ashing procedure followed by a flame AAS determination as described too in EEC doc. 2266/VI/77. Special

  13. Dependence of leachable lead in glazed ceramics on previous treatment: Determination by an improved dithizone extraction method

    Energy Technology Data Exchange (ETDEWEB)

    Schellenberg, K.A. (Eastern Virginia Medical School, Norfolk (United States))

    Fifty six samples of glazed ceramic ware (pottery, porcelain or china cups, plates, bowls, or pitchers) were analyzed for lead by the standard method of allowing the lead to leach into 4% acetic acid over a period of 24 hours at room temperature. The concentration of lead in the acid was determined spectrophotometrically following extraction from an alkaline cyanide solution into a toluene solution of dithizone. Five pieces (9%) were found to leach 7 or more parts per million, and an additional 14 pieces (25%) leached 1 or more parts per million. Analysis of several pieces showed that the amount of lead leached into acid was reduced by as much as three fold when immediately repeated, but the amount reached the original level if the piece was allowed to rest for several days before repeat determinations. This phenomenon was studied further, and the results indicated that leachable lead in glazed pottery was increased by time, temperature, and exposure to alkaline solution. Thus the repeated use of a dishwasher may cause dinnerware that had been previously lead free to leach lead on subsequent use with food. The effect of time of acid elution was also studied, indicating that the majority of lead is dissolved within one minute of addition of acid, with very slow increase over 24 hours.

  14. Trends in study design and the statistical methods employed in a leading general medicine journal.

    Science.gov (United States)

    Gosho, M; Sato, Y; Nagashima, K; Takahashi, S

    2018-02-01

    Study design and statistical methods have become core components of medical research, and the methodology has become more multifaceted and complicated over time. The study of the comprehensive details and current trends of study design and statistical methods is required to support the future implementation of well-planned clinical studies providing information about evidence-based medicine. Our purpose was to illustrate study design and statistical methods employed in recent medical literature. This was an extension study of Sato et al. (N Engl J Med 2017; 376: 1086-1087), which reviewed 238 articles published in 2015 in the New England Journal of Medicine (NEJM) and briefly summarized the statistical methods employed in NEJM. Using the same database, we performed a new investigation of the detailed trends in study design and individual statistical methods that were not reported in the Sato study. Due to the CONSORT statement, prespecification and justification of sample size are obligatory in planning intervention studies. Although standard survival methods (eg Kaplan-Meier estimator and Cox regression model) were most frequently applied, the Gray test and Fine-Gray proportional hazard model for considering competing risks were sometimes used for a more valid statistical inference. With respect to handling missing data, model-based methods, which are valid for missing-at-random data, were more frequently used than single imputation methods. These methods are not recommended as a primary analysis, but they have been applied in many clinical trials. Group sequential design with interim analyses was one of the standard designs, and novel design, such as adaptive dose selection and sample size re-estimation, was sometimes employed in NEJM. Model-based approaches for handling missing data should replace single imputation methods for primary analysis in the light of the information found in some publications. Use of adaptive design with interim analyses is increasing

  15. Virtual reality lead extraction as a method for training new physicians: a pilot study.

    Science.gov (United States)

    Maytin, Melanie; Daily, Thomas P; Carillo, Roger G

    2015-03-01

    It is estimated that the demand for transvenous lead extraction (TLE) has reached an annual extraction rate of nearly 24,000 patients worldwide. Despite technologic advances, TLE still has the potential for significant morbidity and mortality. Complication rates with TLE directly parallel operator experience. However, obtaining adequate training during and postfellowship can be difficult. Given the potential for catastrophic complications and the steep learning curve (up to 300 cases) associated with this procedure, we sought to validate a virtual reality (VR) lead extraction simulator as an innovative training and evaluation tool for physicians new to TLE. We randomized eight electrophysiology fellows to VR simulator versus conventional training. We compared procedural skill competency between the groups using simulator competency, tactile measurements, markers of proficiency and attitudes, and cognitive abilities battery. Practical skills and simulator complications differed significantly between the VR simulator and conventional training groups. The VR simulator group executed patient preparation and procedure performance better than the conventional group (P < 0.01). All four fellows randomized to conventional training experienced a simulator complication (two superior vena cava [SVC] tears, three right ventricle [RV] avulsions) versus one fellow in the VR simulator group (one SVC tear) (P = 0.02). Tactile measurements revealed a trend toward excess pushing versus pulling forces among the conventionally trained group. The time for lead removal was also significantly higher in the conventional training group (12.46 minutes vs 5.54 minutes, P = 0.02). There was no significant difference in baseline or posttraining cognitive ability. We contend that the implementation of alternative training tools such as a VR simulation model will improve physician training and allow for an innovative pathway to assess the achievement of competency. ©2014 Wiley Periodicals, Inc.

  16. The Lead Cooled Fast Reactor Benchmark BREST-300:. Analysis with Sensitivity Method

    Science.gov (United States)

    Smirnov, Valery; Orlov, Victor; Mourogov, Alexandre; Lecarpentier, David; Ivanova, Tatiana

    2006-04-01

    Sustainable development of atomic energy will require development of new types of reactors able to exceed the limits of the existing reactor types in terms of optimum use of natural fuel resources, reduction in the production of long-lived radioactive waste, economic and safety competitiveness. Lead cooled fast neutrons reactor is one of the most interesting candidates with a potential to address these needs. BREST-300 is a 300 MWe lead cooled fast reactor developed by the NIKIET (Russia) with a deterministic safety approach which aims to exclude reactivity margins greater than the delayed neutron fraction. The development of innovative reactors (lead coolant, nitride fuel…) and fuel cycles with new constraints such as cycle closure or actinide burning, requires new technologies and new data from various disciplines: fuel types, fuel designs and fuel reprocessing. In this connection, the tool and neutron data used for the calculational analysis of reactor characteristics requires thorough validation, even if computational codes in Russia and France relies to the calculation of fast reactors' parameters and “fast” experiments. NIKIET developed a reactor benchmark fitting of design type calculational tools (including neutron data). In the frame of technical exchanges between the NIKIET and the EDF (Electricité De France), results of this benchmark calculation concerning the principal parameters of fuel evolution and safety parameters has been intercompared, in order to estimate the uncertainties and validate the codes for calculations of these new kind of reactors. Different codes and cross-sections data have been used, and sensitivity studies have been performed to understand and quantify the uncertainties sources.

  17. A fast method for the determination of lead in honey samples using stabilizer-free silver nanoparticles

    Science.gov (United States)

    Bittar, Dayana Borges; Catelani, Tiago Augusto; Pezza, Leonardo; Pezza, Helena Redigolo

    2018-01-01

    A sensitive, rapid and robust method based on the use of stabilizer-free silver nanoparticles was developed for lead detection in honey. Silver nanoparticles were synthesized without the presence of any stabilizers using silver nitrate and sodium borohydride as precursors where the latter was applied as reducing agent. The optimization of the experimental variables (AgNO3 and NaBH4) for the formation of the nanoparticles was carried out using varying volumes of these solutions. Spectrophotometric measurements at 393 nm showed a linear working range between 0.0500 and 0.167 mg L- 1 lead (R = 0.994), with limits of detection (LOD) and quantification (LOQ) of 0.0135 and 0.0451 mg L- 1, respectively. The proposed method proved to be a significantly sensitive mechanism for lead detection in honey samples.

  18. Bounded perturbation resilience of extragradient-type methods and their applications.

    Science.gov (United States)

    Dong, Q-L; Gibali, A; Jiang, D; Tang, Y

    2017-01-01

    In this paper we study the bounded perturbation resilience of the extragradient and the subgradient extragradient methods for solving a variational inequality (VI) problem in real Hilbert spaces. This is an important property of algorithms which guarantees the convergence of the scheme under summable errors, meaning that an inexact version of the methods can also be considered. Moreover, once an algorithm is proved to be bounded perturbation resilience, superiorization can be used, and this allows flexibility in choosing the bounded perturbations in order to obtain a superior solution, as well explained in the paper. We also discuss some inertial extragradient methods. Under mild and standard assumptions of monotonicity and Lipschitz continuity of the VI's associated mapping, convergence of the perturbed extragradient and subgradient extragradient methods is proved. In addition we show that the perturbed algorithms converge at the rate of [Formula: see text]. Numerical illustrations are given to demonstrate the performances of the algorithms.

  19. Bounded perturbation resilience of extragradient-type methods and their applications

    Directory of Open Access Journals (Sweden)

    Q-L Dong

    2017-11-01

    Full Text Available Abstract In this paper we study the bounded perturbation resilience of the extragradient and the subgradient extragradient methods for solving a variational inequality (VI problem in real Hilbert spaces. This is an important property of algorithms which guarantees the convergence of the scheme under summable errors, meaning that an inexact version of the methods can also be considered. Moreover, once an algorithm is proved to be bounded perturbation resilience, superiorization can be used, and this allows flexibility in choosing the bounded perturbations in order to obtain a superior solution, as well explained in the paper. We also discuss some inertial extragradient methods. Under mild and standard assumptions of monotonicity and Lipschitz continuity of the VI’s associated mapping, convergence of the perturbed extragradient and subgradient extragradient methods is proved. In addition we show that the perturbed algorithms converge at the rate of O ( 1 / t $O(1/t$ . Numerical illustrations are given to demonstrate the performances of the algorithms.

  20. Modeling of radio-frequency induced currents on lead wires during MR imaging using a modified transmission line method.

    Science.gov (United States)

    Acikel, Volkan; Atalar, Ergin

    2011-12-01

    Metallic implants may cause serious tissue heating during magnetic resonance (MR) imaging. This heating occurs due to the induced currents caused by the radio-frequency (RF) field. Much work has been done to date to understand the relationship between the RF field and the induced currents. Most of these studies, however, were based purely on experimental or numerical methods. This study has three main purposes: (1) to define the RF heating properties of an implant lead using two parameters; (2) to develop an analytical formulation that directly explains the relationship between RF fields and induced currents; and (3) to form a basis for analysis of complex cases. In this study, a lumped element model of the transmission line was modified to model leads of implants inside the body. Using this model, leads are defined using two parameters: impedance per unit length, Z, and effective wavenumber along the lead, k(t). These two parameters were obtained by using methods that are similar to the transmission line theory. As long as these parameters are known for a lead, currents induced in the lead can be obtained no matter how complex the lead geometry is. The currents induced in bare wire, lossy wire, and insulated wire were calculated using this new method which is called the modified transmission line method or MoTLiM. First, the calculated induced currents under uniform electric field distribution were solved and compared with method-of-moments (MoM) calculations. In addition, MoTLiM results were compared with those of phantom experiments. For experimental verification, the flip angle distortion due to the induced currents was used. The flip angle distribution around a wire was both measured by using flip angle imaging methods and calculated using current distribution obtained from the MoTLiM. Finally, these results were compared and an error analysis was carried out. Bare perfect electric, bare lossy, and insulated perfect electric conductor wires under uniform and

  1. Research on output signal of piezoelectric lead zirconate titanate detector using Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Takechi, Seiji, E-mail: takechi@elec.eng.osaka-cu.ac.jp [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Mitsuhashi, Tomoaki; Miura, Yoshinori [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Miyachi, Takashi; Kobayashi, Masanori; Okudaira, Osamu [Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan); Shibata, Hiromi [The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Fujii, Masayuki [Famscience Co., Ltd., Tsukubamirai, Ibaraki 300-2435 (Japan); Okada, Nagaya [Honda Electronics Co., Ltd., Toyohashi, Aichi 441-3193 (Japan); Murakami, Takeshi; Uchihori, Yukio [National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2017-06-21

    The response of a radiation detector fabricated from piezoelectric lead zirconate titanate (PZT) was studied. The response signal due to a single 400 MeV/n xenon (Xe) ion was assumed to have a simple form that was composed of two variables, the amplitude and time constant. These variables were estimated by comparing two output waveforms obtained from a computer simulation and an experiment on Xe beam irradiation. Their values appeared to be dependent on the beam intensity. - Highlights: • The performance of PZT detector was studied by irradiation of a 400 MeV/n Xe beam. • Monte Carlo simulation was used to examine the formation process of the output. • The response signal due to a single Xe ion was assumed to have a simple form. • The form was composed of two variables, the amplitude and time constant. • These variables appeared to be dependent on the beam intensity.

  2. Comparison of four bioindication methods for assessing the degree of environmental lead and cadmium pollution

    Energy Technology Data Exchange (ETDEWEB)

    Dmuchowski, Wojciech, E-mail: w.dmuchowski@obpan.pl [Botanical Garden-Center for Conservation of Biological Diversity, Polish Academy of Science, Prawdziwka 2, 02-973 Warsaw (Poland); Warsaw University of Life Sciences-SGGW, Faculty of Agriculture and Biology, 159 Nowoursynowska 159, 02-776 Warsaw (Poland); Gozdowski, Dariusz, E-mail: dariusz_gozdowski@sggw.pl [Warsaw University of Life Sciences-SGGW, Faculty of Agriculture and Biology, 159 Nowoursynowska 159, 02-776 Warsaw (Poland); Baczewska, Aneta Helena [Botanical Garden-Center for Conservation of Biological Diversity, Polish Academy of Science, Prawdziwka 2, 02-973 Warsaw (Poland)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer In this study we examined level of contamination in extremely heavy polluted area. Black-Right-Pointing-Pointer We examined four various bioindication methods. Black-Right-Pointing-Pointer Results were presented in pollution maps. Black-Right-Pointing-Pointer We evaluated relationships between examined bioindication methods. - Abstract: The purpose of this study was to assess the application of several bioindication methods for the monitoring of environmental pollution from Pb and Cd. The study area centered on the town of Olkusz, Poland, which is one of the oldest centers for the metallurgical industry in Europe. The assessment of environmental pollution due to metals was performed using four frequently used bioindication methods: moss-bag (Sphagnum fallax), determination of metal accumulation in Pleurozium schreberi, silver birch foliage, and Scots pine needles. The region of Olkusz, and especially the area surrounding the mining and metallurgical Boleslaw complex, was extremely contaminated with Pb and Cd. The results of the investigations are presented as contamination deposition maps. Despite the application of various methods and the resulting diversity of the specific exposure periods for different biomonitors, the spatial distribution of contamination shown on the maps was similar, as confirmed by the statistical analysis of the results.

  3. Flipping the Graduate Qualitative Research Methods Classroom: Did It Lead to Flipped Learning?

    Science.gov (United States)

    Earley, Mark

    2016-01-01

    The flipped, or inverted, classroom has gained popularity in a variety of fields and at a variety of educational levels, from K-12 through higher education. This paper describes the author's positive experience flipping a graduate qualitative research methods classroom. After a review of the current literature on flipped classrooms in higher…

  4. Phosphorus Amendment Efficacy for In Situ Remediation of Soil Lead Depends on the Bioaccessible Method

    Science.gov (United States)

    A validated method is needed to measure reductions of in vitro bioaccessible (IVBA) Pb in urban soil remediated with amendments. This study evaluated the effect of in vitro extraction solution pH and glycine buffer on bioaccesible Pb in P-treated soils. Two Pb-contaminated soils...

  5. 78 FR 8066 - Method for the Determination of Lead in Total Suspended Particulate Matter

    Science.gov (United States)

    2013-02-05

    ... fountain or eye wash bottle be available during performance of this method. An eye wash bottle has a spout that covers the eye. If acid or any other corrosive gets into the eye, the water in this bottle is... threaded caps for extraction and storage, SCP Science DigiTUBE Item No. 010- 500-063, or equivalent...

  6. 78 FR 40000 - Method for the Determination of Lead in Total Suspended Particulate Matter

    Science.gov (United States)

    2013-07-03

    ... extraction, and also knowledge in the recognition and in the correction of spectral, chemical and physical... improved extraction methods that are now available with improved precision, sample throughput, and extraction efficiency; (2) address advances in measurement technology that have occurred since promulgation...

  7. Determination of Trace Amounts of Lead with ETAAS After Single Drop Microextraction and Dispersive Liquid Liquid Microextraction Methods

    Directory of Open Access Journals (Sweden)

    Efeçınar M.

    2013-04-01

    Full Text Available Two liquid-phase microextraction procedures, single-drop microextraction (SDME and dispersive liquid–liquid microextraction (DLLME, have been developed for the determination of lead by electrothermal atomic absorption spectrometry (ETAAS. Both methods were based on the formation of lead iodide-Rhodamine B complex which is in phosphoric acid medium. In the presence of KI, anionic lead iodide was complexed with Rhodamine B as an ion-association complex. Several factors that may be affected on the SDME and DLLME methods were optimized. In the optimum experimental conditions, the limit of detection (3s and the enhancement factor were 0.008 μgL−1 and 152 for SDME and 0.0129 μgL−1 and 89 for DLLME respectively. The relative standard deviation (RSD for eight replicate determinations of 0.25 μgL−1 Pb was 4.6% for SDME and 0.5 μgL−1 Pb was 2.9% for DLLME. The developed methods were validated by the analysis of certified reference materials, and applied successfully to the determination of lead in several water and food samples.

  8. Leveraging Data Fusion Strategies in Multireceptor Lead Optimization MM/GBSA End-Point Methods.

    Science.gov (United States)

    Knight, Jennifer L; Krilov, Goran; Borrelli, Kenneth W; Williams, Joshua; Gunn, John R; Clowes, Alec; Cheng, Luciano; Friesner, Richard A; Abel, Robert

    2014-08-12

    Accurate and efficient affinity calculations are critical to enhancing the contribution of in silico modeling during the lead optimization phase of a drug discovery campaign. Here, we present a large-scale study of the efficacy of data fusion strategies to leverage results from end-point MM/GBSA calculations in multiple receptors to identify potent inhibitors among an ensemble of congeneric ligands. The retrospective analysis of 13 congeneric ligand series curated from publicly available data across seven biological targets demonstrates that in 90% of the individual receptor structures MM/GBSA scores successfully identify subsets of inhibitors that are more potent than a random selection, and data fusion strategies that combine MM/GBSA scores from each of the receptors significantly increase the robustness of the predictions. Among nine different data fusion metrics based on consensus scores or receptor rankings, the SumZScore (i.e., converting MM/GBSA scores into standardized Z-Scores within a receptor and computing the sum of the Z-Scores for a given ligand across the ensemble of receptors) is found to be a robust and physically meaningful metric for combining results across multiple receptors. Perhaps most surprisingly, even with relatively low to modest overall correlations between SumZScore and experimental binding affinities, SumZScore tends to reliably prioritize subsets of inhibitors that are at least as potent as those that are prioritized from a "best" single receptor identified from known compounds within the congeneric series.

  9. A Novel Method for the Prediction of Critical Inclusion Size Leading to Fatigue Failure

    Science.gov (United States)

    Saberifar, S.; Mashreghi, A. R.

    2012-06-01

    The fatigue behavior of two commercial 30MnVS6 steels with similar microstructure and mechanical properties containing inclusions of different sizes were studied in the 107 cycles fatigue regime. The scanning electron microscopy (SEM) investigations of the fracture surfaces revealed that the nonmetallic inclusions are the main sources of fatigue crack initiation. Calculated according to the Murakami's model, the stress intensity factors were found to be suitable for the assessment of fatigue behavior. In this article, a new method is proposed for the prediction of the critical inclusion size, using Murakami's model. According to this method, a critical stress intensity factor was determined for the estimation of the critical inclusion size causing the fatigue failure.

  10. Standard test method for graphite furnace atomic absorption spectrometric determination of lead and cadmium extracted from ceramic foodware

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method covers procedures for using graphite furnace atomic absorption spectroscopy (GFAAS) to quantitatively determine lead and cadmium extracted by acetic acid at room temperature from the food-contact surface of foodware. The method is applicable to food-contact surfaces composed of silicate-based materials (earthenware, glazed ceramicware, decorated ceramicware, decorated glass, and lead crystal glass) and is capable of determining lead concentrations greater than 0.005 to 0.020 g/mL and cadmium concentrations greater than 0.0005 to 0.002 g/mL, depending on instrument design. 1.2 This test method also describes quality control procedures to check for contamination and matrix interference during GFAAS analyses and a specific sequence of analytical measurements that demonstrates proper instrument operation during the time period in which sample solutions are analyzed. 1.3 Cleaning and other contamination control procedures are described in this test method. Users may modify contamination cont...

  11. Leading for the long haul: a mixed-method evaluation of the Sustainment Leadership Scale (SLS).

    Science.gov (United States)

    Ehrhart, Mark G; Torres, Elisa M; Green, Amy E; Trott, Elise M; Willging, Cathleen E; Moullin, Joanna C; Aarons, Gregory A

    2018-01-19

    Despite our progress in understanding the organizational context for implementation and specifically the role of leadership in implementation, its role in sustainment has received little attention. This paper took a mixed-method approach to examine leadership during the sustainment phase of the Exploration, Preparation, Implementation, Sustainment (EPIS) framework. Utilizing the Implementation Leadership Scale as a foundation, we sought to develop a short, practical measure of sustainment leadership that can be used for both applied and research purposes. Data for this study were collected as a part of a larger mixed-method study of evidence-based intervention, SafeCare®, sustainment. Quantitative data were collected from 157 providers using web-based surveys. Confirmatory factor analysis was used to examine the factor structure of the Sustainment Leadership Scale (SLS). Qualitative data were collected from 95 providers who participated in one of 15 focus groups. A framework approach guided qualitative data analysis. Mixed-method integration was also utilized to examine convergence of quantitative and qualitative findings. Confirmatory factor analysis supported the a priori higher order factor structure of the SLS with subscales indicating a single higher order sustainment leadership factor. The SLS demonstrated excellent internal consistency reliability. Qualitative analyses offered support for the dimensions of sustainment leadership captured by the quantitative measure, in addition to uncovering a fifth possible factor, available leadership. This study found qualitative and quantitative support for the pragmatic SLS measure. The SLS can be used for assessing leadership of first-level leaders to understand how staff perceive leadership during sustainment and to suggest areas where leaders could direct more attention in order to increase the likelihood that EBIs are institutionalized into the normal functioning of the organization.

  12. Comparison of two methods for blood lead analysis in cattle: graphite-furnace atomic absorption spectrometry and LeadCare(R) II system.

    Science.gov (United States)

    Bischoff, Karyn; Gaskill, Cynthia; Erb, Hollis N; Ebel, Joseph G; Hillebrandt, Joseph

    2010-09-01

    The current study compared the LeadCare(R) II test kit system with graphite-furnace atomic absorption spectrometry for blood lead (Pb) analysis in 56 cattle accidentally exposed to Pb in the field. Blood Pb concentrations were determined by LeadCare II within 4 hr of collection and after 72 hr of refrigeration. Blood Pb concentrations were determined by atomic absorption spectrometry, and samples that were coagulated (n = 12) were homogenized before analysis. There was strong rank correlation (R(2) = 0.96) between atomic absorption and LeadCare II (within 4 hr of collection), and a conversion formula was determined for values within the observed range (3-91 mcg/dl, although few had values >40 mcg/dl). Median and mean blood pb concentrations for atomic absorption were 7.7 and 15.9 mcg/dl, respectively; for LeadCare II, medians were 5.2 mcg/dl at 4 hr and 4.9 mcg/dl at 72 hr, and means were 12.4 and 11.7, respectively. LeadCare II results at 4 hr strongly correlated with 72 hr results (R(2) = 0.96), but results at 72 hr were lower (P atomic absorption. Although there have been several articles that compared LeadCare with other analytical techniques, all were for the original system, not LeadCare II. The present study indicated that LeadCare II results correlated well with atomic absorption over a wide range of blood Pb concentrations and that refrigerating samples for up to 72 hr before LeadCare II analysis was acceptable for clinical purposes.

  13. Production Method that Leads to TiO2 Nanofibrous Structure Usable in Food Packaging

    Directory of Open Access Journals (Sweden)

    Kovář Radovan

    2016-12-01

    Full Text Available Burned inorganic nanofibers most often occur in the nature in two forms: rutile and anatase. Today, the production of rutile is about to end, while anatase provides more application possibilities. The resulting fiber structure is determined by calcination. It is necessary to find the optimal temperature as well as time, during which the fibers must withstand temperature load. For such method of calcination, it is necessary to create a special design of continuous furnace. Anatase has application in food packaging. Packages containing anatase are used for: food safety, improved packaging for spoilage reduction, sensors for detection of pathogens and spoilage, disinfectants and antimicrobial surfaces.

  14. FACILE SYNTHESIS OF SEMICONDUCTING NANOSIZED 0D AND 2D LEAD OXIDES USING A MODIFIED CO-PRECIPITATION METHOD

    Directory of Open Access Journals (Sweden)

    Ahmet Güngör

    2017-09-01

    Full Text Available Nano-sized lead has many versatile applications that could be applied in daily life. In the current study, we report a comprehensive study for preparation of nanosized lead oxide using the co-precipitation method and optimization of reaction parameters to obtain lead oxide (PbO nanoparticles with homogeneously distributed size, shape and structure. When aqueous solution of lead (II acetate reduced with sodium hydroxide at elevated temperatures, alpha form of lead oxide nanoparticles, with spherical shape were achieved. Decreasing the ratio of sodium hydroxide to lead (II acetate concentration at moderate temperatures resulted with a gradual change in crystal structure from quasi -spherical α-PbO nanoparticles and two dimensional nanoflakes of beta PbO with a thickness below 100 nm was synthesized for the first time. The obtained particles in both α and b forms were characterized by X-ray powder diffraction (XRD, dynamic light scattering equipment (Zetasizer, transmission electron microscopy (TEM, scanning electron microscopy (SEM and Fourier transform infrared spectroscopy (FTIR. Finally, thin layers of freeze-dryer α-PbO and β-PbO particle powder on glass and filter paper were formed by the help of nail polisher and conductivity measurements were performed using four-point probes method. Produced layers β-PbO particles with a below 100 nm showed higher conductivity on both supports as compared to the ones produced from spherical α-PbO nanoparticles. This altered conductivity of the material in the semiconducting zone, which is probably due to a more effective electron transfer facilitated by 2D alignment of the molecules, could rose the potential use of this material in voltaic and catalysis.

  15. Fabrication of transparent lead-free KNN glass ceramics by incorporation method.

    Science.gov (United States)

    Yongsiri, Ploypailin; Eitssayeam, Sukum; Rujijanagul, Gobwut; Sirisoonthorn, Somnuk; Tunkasiri, Tawee; Pengpat, Kamonpan

    2012-02-16

    The incorporation method was employed to produce potassium sodium niobate [KNN] (K0.5Na0.5NbO3) glass ceramics from the KNN-SiO2 system. This incorporation method combines a simple mixed-oxide technique for producing KNN powder and a conventional melt-quenching technique to form the resulting glass. KNN was calcined at 800°C and subsequently mixed with SiO2 in the KNN:SiO2 ratio of 75:25 (mol%). The successfully produced optically transparent glass was then subjected to a heat treatment schedule at temperatures ranging from 525°C -575°C for crystallization. All glass ceramics of more than 40% transmittance crystallized into KNN nanocrystals that were rectangular in shape and dispersed well throughout the glass matrix. The crystal size and crystallinity were found to increase with increasing heat treatment temperature, which in turn plays an important role in controlling the properties of the glass ceramics, including physical, optical, and dielectric properties. The transparency of the glass samples decreased with increasing crystal size. The maximum room temperature dielectric constant (εr) was as high as 474 at 10 kHz with an acceptable low loss (tanδ) around 0.02 at 10 kHz.

  16. Jewellery: alloy composition and release of nickel, cobalt and lead assessed with the EU synthetic sweat method.

    Science.gov (United States)

    Hamann, Dathan; Thyssen, Jacob P; Hamann, Carsten R; Hamann, Curtis; Menné, Torkil; Johansen, Jeanne D; Spiewak, Radoslaw; Maibach, Howard; Lundgren, Lennart; Lidén, Carola

    2015-10-01

    Several studies have shown nickel and cobalt release from jewellery by using spot tests, but the metal composition of jewellery is largely unknown. To evaluate the metal composition of a large worldwide sample of mainly inexpensive jewellery items, and investigate the release of nickel, cobalt and lead from a subsample by using EN 1811:1998-required methods. A total of 956 metallic jewellery components were examined with X-ray fluorescence spectroscopy. A subsample of 96 jewellery items purchased in the United States were investigated for nickel, cobalt and lead release by the use of artificial sweat immersion and plasma optical emission spectroscopy. Eighteen elements were detected. The 10 most frequently occurring were, in order of frequency, copper, iron, zinc, nickel, silver, chromium, tin, manganese, lead, and cobalt. Release of nickel was noted from 79 of the 96 US samples (0.01-98 µg/cm(2) /week), release of cobalt from 35 samples (0.02-0.5 µg/cm(2) /week), and release of lead from 37 samples (0.03-2718 µg/cm(2) /week). We present here a comprehensive list of the most frequently encountered metals in jewellery and fashion accessories. Different allergenic and non-allergenic metals are utilized. We also report the frequent release of nickel, cobalt and lead from these objects, despite legislative restrictions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Mathematical forecasting methods for predicting lead contents in animal organs on the basis of the environmental conditions.

    Science.gov (United States)

    Czech, Tomasz; Gambuś, Florian; Wieczorek, Jerzy

    2014-12-01

    The main objective of this study was to determine and describe the lead transfer in the soil-plant-animal system in areas polluted with this metal at varying degrees, with the use of mathematical forecasting methods and data mining tools contained in the Statistica 9.0 software programme. The starting point for the forecasting models comprised results derived from an analysis of different features of soil and plants, collected from 139 locations in an area covering 100km(2) around a lead-zinc ore mining and processing plant ('Boleslaw'), at Bukowno in southern Poland. In addition, the lead content was determined in the tissues and organs of 110 small rodents (mainly mice) caught in the same area. The prediction models, elaborated with the use of classification algorithms, forecasted with high probability the class (range) of pollution in animal tissues and organs with lead, based on various soil and plant properties of the study area. However, prediction models which use multilayer neural networks made it possible to calculate the content of lead (predicted versus measured) in animal tissues and organs with an excellent correlation coefficient. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. The lead-lag relationship between stock index and stock index futures: A thermal optimal path method

    Science.gov (United States)

    Gong, Chen-Chen; Ji, Shen-Dan; Su, Li-Ling; Li, Sai-Ping; Ren, Fei

    2016-02-01

    The study of lead-lag relationship between stock index and stock index futures is of great importance for its wide application in hedging and portfolio investments. Previous works mainly use conventional methods like Granger causality test, GARCH model and error correction model, and focus on the causality relation between the index and futures in a certain period. By using a non-parametric approach-thermal optimal path (TOP) method, we study the lead-lag relationship between China Securities Index 300 (CSI 300), Hang Seng Index (HSI), Standard and Poor 500 (S&P 500) Index and their associated futures to reveal the variance of their relationship over time. Our finding shows evidence of pronounced futures leadership for well established index futures, namely HSI and S&P 500 index futures, while index of developing market like CSI 300 has pronounced leadership. We offer an explanation based on the measure of an indicator which quantifies the differences between spot and futures prices for the surge of lead-lag function. Our results provide new perspectives for the understanding of the dynamical evolution of lead-lag relationship between stock index and stock index futures, which is valuable for the study of market efficiency and its applications.

  19. Blood Lead Concentrations in Children and Method of Water Fluoridation in the United States, 1988–1994

    Science.gov (United States)

    Macek, Mark D.; Matte, Thomas D.; Sinks, Thomas; Malvitz, Dolores M.

    2006-01-01

    Some have hypothesized that community water containing sodium silicofluoride and hydrofluosilicic acid may increase blood lead (PbB) concentrations in children by leaching of lead from water conduits and by increasing absorption of lead from water. Our analysis aimed to evaluate the relation between water fluoridation method and PbB concentrations in children. We used PbB concentration data (n = 9,477) from the Third National Health and Nutrition Examination Survey (1988–1994) for children 1–16 years of age, merged with water fluoridation data from the 1992 Fluoridation Census. The main outcome measure was geometric mean PbB concentration, and covariates included age, sex, race/ethnicity, poverty status, urbanicity, and length of time living in residence. Geometric mean PbB concentrations for each water fluoridation method were 2.40 μg/dL (sodium silicofluoride), 2.34 μg/dL (hydrofluosilicic acid), 1.78 μg/dL (sodium fluoride), 2.24 μg/dL (natural fluoride and no fluoride), and 2.14 μg/dL (unknown/mixed status). In multiple linear and logistic regression, there was a statistical interaction between water fluoridation method and year in which dwelling was built. Controlling for covariates, water fluoridation method was significant only in the models that included dwellings built before 1946 and dwellings of unknown age. Across stratum-specific models for dwellings of known age, neither hydrofluosilicic acid nor sodium silicofluoride were associated with higher geometric mean PbB concentrations or prevalence values. Given these findings, our analyses, though not definitive, do not support concerns that silicofluorides in community water systems cause higher PbB concentrations in children. Current evidence does not provide a basis for changing water fluoridation practices, which have a clear public health benefit. PMID:16393670

  20. Systematic Design of the Lead-Lag Network Method for Active Damping in LCL-Filter Based Three Phase Converters

    DEFF Research Database (Denmark)

    Alzola, Rafael Pena; Liserre, Marco; Blaabjerg, Frede

    2014-01-01

    ) nor its rationale has been explained. Thus, in this paper a straightforward procedure is developed to tune the lead-lag network with the help of software tools. The rationale of this procedure, based on the capacitor current feedback, is elucidated. Stability is studied by means of the root locus......Three-phase active rectifiers guarantee sinusoidal input currents and unity power factor at the price of a high switching frequency ripple. To adopt an LCL-filter, instead of an L-filter, allows using reduced values for the inductances and so preserving dynamics. However, stability problems can...... without using dissipative elements but, sometimes, needing additional sensors. This solution has been addressed in many publications. The lead-lag network method is one of the first reported procedures and continues being in use. However, neither there is a direct tuning procedure (without trial and error...

  1. Measuring flow velocity on frozen and non-frozen slopes of black soil through leading edge method

    Directory of Open Access Journals (Sweden)

    Chao Chen

    2017-09-01

    Full Text Available Flow velocity is a major parameter related to hillslope hydrodynamics erosion. This study aims to measure flow velocity over frozen and non-frozen slopes through leading edge method before being calibrated with accurate flow velocity to determine the correct coefficient for convenience of flow velocity measurement. Laboratory experiments were conducted on frozen and non-frozen soil slopes with flumes involving four slope gradients of 5°, 10°, 15°, and 20°and three flow rates of 1, 2, and 4 L/min with a flume of 6 m long and 0.1 m wide. The measurements were made with a stopwatch to record the time duration that the water flow ran over the rill segments of 2, 4 and 6 m long. Accurate flow velocity was measured with electrolyte trace method, under pulse boundary condition. The leading edge and accurate flow velocities were used to determine the correction coefficient to convert the former to the latter. Results showed that the correction coefficient on frozen soil slope was 0.81 with a coefficient of determination (R2 of 0.99. The correction coefficient on non-frozen soil slope was 0.79 with R2 of 0.98. A coefficient of 0.8 was applicable to both soil surface conditions. The accurate velocities on the four frozen black soil slopes were approximately 30%, 54%, 71%, and 91% higher than those on non-frozen soil slopes. By contrast, the leading edge flow velocities on the frozen soil slopes were 23%, 54%, 67%, and 84% higher than those on non-frozen soil slopes. The flow velocities on frozen soil slopes increased with flow rate at all four slopes, but they increased from 5 to 15° before getting stabilized. Therefore, rill flow velocity can be effectively measured with leading edge method by multiplying the leading edge velocity with a correction coefficient of 0.80. This study provides a strategy to measure rill flow velocity for studies on soil erosion mechanisms.

  2. Assessment of the effectiveness of attenuation of leaded aprons through TLD dosimetry and Monte Carlo simulation method

    Energy Technology Data Exchange (ETDEWEB)

    Olaya D, H.; Diaz M, J. A.; Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, 150003 Tunja, Boyaca (Colombia); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2016-10-15

    Were performed experimental setups using an X-ray equipment continuous emission Pantak DXT-3000 and three types of leaded aprons with thickness of 0.25, 0.5 and 0.75 mm coated with Mylar Fiber coated Mylar on its surface. Apron was located at a distance of 2.5 m with respect focus in order to cover a radiation field size of a meter in diameter. At the beam output were added aluminum filtration in order to reproduce qualities of narrow beams N-40 (E{sub efective} = 33 keV), N-80 (E{sub efective} = 65 keV) and N-100 (E{sub efective} = 83 keV) according to the ISO standard 4037 (1-3). Each lead apron were fixed 10 TLD dosimeters over its surface, 5 dosimeters before and 5 dosimeters after with respect to X-ray beam and were calibrated for Harshaw 4500 thermoluminescent reader system order to assess the attenuation of each apron. Were performed dosimeters readings and were calculated the attenuation coefficients for each effective energy of X-ray quality. In order to confirm the method of effective energy of ISO-4037 and evaluate effectiveness of lead aprons based on energy range for each medical practice was made a Monte Carlo simulation using code GEANT-4, calculating the fluence and absorbed dose in each one of the dosimeters Monte Carlo, then coefficients of linear attenuation were calculated and compared with the experimental data and reported by the National Institute of Standards and Technology (Nist). Finally, results are consistent between theoretical calculation and experimental measures. This work will serve to make assessments for other personalized leaded protections. (Author)

  3. A Decomposition-Based Pricing Method for Solving a Large-Scale MILP Model for an Integrated Fishery

    Directory of Open Access Journals (Sweden)

    M. Babul Hasan

    2007-01-01

    The IFP can be decomposed into a trawler-scheduling subproblem and a fish-processing subproblem in two different ways by relaxing different sets of constraints. We tried conventional decomposition techniques including subgradient optimization and Dantzig-Wolfe decomposition, both of which were unacceptably slow. We then developed a decomposition-based pricing method for solving the large fishery model, which gives excellent computation times. Numerical results for several planning horizon models are presented.

  4. Evaluation of purity with its uncertainty value in high purity lead stick by conventional and electro-gravimetric methods.

    Science.gov (United States)

    Singh, Nahar; Singh, Niranjan; Tripathy, S Swarupa; Soni, Daya; Singh, Khem; Gupta, Prabhat K

    2013-06-26

    A conventional gravimetry and electro-gravimetry study has been carried out for the precise and accurate purity determination of lead (Pb) in high purity lead stick and for preparation of reference standard. Reference materials are standards containing a known amount of an analyte and provide a reference value to determine unknown concentrations or to calibrate analytical instruments. A stock solution of approximate 2 kg has been prepared after dissolving approximate 2 g of Pb stick in 5% ultra pure nitric acid. From the stock solution five replicates of approximate 50 g have been taken for determination of purity by each method. The Pb has been determined as PbSO4 by conventional gravimetry, as PbO2 by electro gravimetry. The percentage purity of the metallic Pb was calculated accordingly from PbSO4 and PbO2. On the basis of experimental observations it has been concluded that by conventional gravimetry and electro-gravimetry the purity of Pb was found to be 99.98 ± 0.24 and 99.97 ± 0.27 g/100 g and on the basis of Pb purity the concentration of reference standard solutions were found to be 1000.88 ± 2.44 and 1000.81 ± 2.68 mg kg-1 respectively with 95% confidence level (k = 2). The uncertainty evaluation has also been carried out in Pb determination following EURACHEM/GUM guidelines. The final analytical results quantifying uncertainty fulfills this requirement and gives a measure of the confidence level of the concerned laboratory. Gravimetry is the most reliable technique in comparison to titremetry and instrumental method and the results of gravimetry are directly traceable to SI unit. Gravimetric analysis, if methods are followed carefully, provides for exceedingly precise analysis. In classical gravimetry the major uncertainties are due to repeatability but in electro-gravimetry several other factors also affect the final results.

  5. Rapid Generation of miRNA Inhibitor Leads by Bioinformatics and Efficient High-Throughput Screening Methods.

    Science.gov (United States)

    Haga, Christopher L; Velagapudi, Sai Pradeep; Childs-Disney, Jessica L; Strivelli, Jacqueline; Disney, Matthew D; Phinney, Donald G

    2017-01-01

    The discovery of microRNAs (miRNAs) has opened an entire new avenue for drug development. These short (15-22 nucleotides) noncoding RNAs, which function in RNA silencing and posttranscriptional regulation of gene expression, have been shown to critically affect numerous pathways in both development and disease progression. Current miRNA drug development focuses on either reintroducing the miRNA into cells through the use of a miRNA mimic or inhibiting its function via use of a synthetic antagomir. Although these methods have shown some success as therapeutics, they face challenges particularly with regard to cellular uptake and for use as systemic reagents. We recently presented a novel mechanism of inhibiting miR-544 by directed inhibition of miRNA biogenesis. We found that inhibition of DICER processing of miR-544 through the use of a small molecule abolished miR-544 function in regulating adaptation of breast cancer cells to hypoxic stress. Herein, we describe a protocol that utilizes bioinformatics to first identify lead small molecules that bind to DICER cleavage sites in pre-miRNAs and then employ an efficient, high-throughput fluorescent-based screening system to determine the inhibitory potential of the lead compounds and their derivatives.

  6. High-dose biotin therapy leading to false biochemical endocrine profiles: validation of a simple method to overcome biotin interference.

    Science.gov (United States)

    Piketty, Marie-Liesse; Prie, Dominique; Sedel, Frederic; Bernard, Delphine; Hercend, Claude; Chanson, Philippe; Souberbielle, Jean-Claude

    2017-05-01

    High-dose biotin therapy is beneficial in progressive multiple sclerosis (MS) and is expected to be adopted by a large number of patients. Biotin therapy leads to analytical interference in many immunoassays that utilize streptavidin-biotin capture techniques, yielding skewed results that can mimic various endocrine disorders. We aimed at exploring this interference, to be able to remove biotin and avoid misleading results. We measured free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), parathyroid homrone (PTH), 25-hydroxyvitamin D (25OHD), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, C-peptide, cortisol (Roche Diagnostics assays), biotin and its main metabolites (liquid chromatography tandem mass spectrometry) in 23 plasmas from MS patients and healthy volunteers receiving high-dose biotin, and in 39 biotin-unsupplemented patients, before and after a simple procedure (designated N5) designed to remove biotin by means of streptavidin-coated microparticles. We also assayed fT4, TSH and PTH in the 23 high-biotin plasmas using assays not employing streptavidin-biotin binding. The biotin concentration ranged from 31.7 to 1160 µg/L in the 23 high-biotin plasmas samples. After the N5 protocol, the biotin concentration was below the detection limit in all but two samples (8.3 and 27.6 μg/L). Most hormones results were abnormal, but normalized after N5. All results with the alternative methods were normal except two slight PTH elevations. In the 39 biotin-unsupplemented patients, the N5 protocol did not affect the results for any of the hormones, apart from an 8.4% decrease in PTH. We confirm that most streptavidin-biotin hormone immunoassays are affected by high biotin concentrations, leading to a risk of misdiagnosis. Our simple neutralization method efficiently suppresses biotin interference.

  7. Radiation Protection Clothing in X-Ray Diagnostics - Influence of the Different Methods of Measurement on the Lead Equivalent and the Required Mass.

    Science.gov (United States)

    Schöpf, T; Pichler, T

    2016-08-01

    The determination of attenuation compared to lead for lead-free and lead-reduced protective clothing depends strongly on the different methods of measurement. The standards EN 61331-1 (2002), DIN 6857-1 und IEC 61331-1 (2014) are now available for the testing of protective clothing. These standards define methods in the narrow beam and in the inverse broad beam geometry with partially different radiation qualities. In the narrow beam the scattered radiation and fluorescence are not considered due to the arrangement. Therefore, the protective effect of lead-free materials will be incorrectly estimated compared to lead material. The influence of the different methods of measurement on the lead equivalent and the required mass of radiation protection clothing was examined. The lead equivalents for material samples for commercially available protective clothing were determined. These samples were made of lead and lead-reduced and lead-free materials. For determination of the attenuation equivalents, certified lead foils with high purity and a precise thickness of 0.05 to 1.25 mm were used. The measurements indicate that the lead equivalent depends on the method of measurement and the radiation quality. For X-ray tube voltages below 110 kV, lead-free or lead-reduced materials show a higher lead equivalent compared to lead material in some cases. Significant mass reductions of more than 10 % compared to lead material are only achievable with a limited range of use up to 100 kV. The implementation of an internationally accepted measuring standard for radiation protection clothing is reasonable and necessary. If standard IEC 61331-1 (2014) can fill this role is unknown. Key points • The attenuation factor and the lead equivalent depend strongly on the method of measurement.• The used X-ray spectra are only partially comparable with the spectra of scattered radiation.• Mass reductions for protective clothing are only achievable with a limited range of

  8. A rapid method for simultaneous determination of arsenic, cadmium and lead in drinking water by inductively coupled plasma mass spectrometry

    Directory of Open Access Journals (Sweden)

    Joshua Rey P. Torres

    Full Text Available The raw water source of drinking water in most areas in the Philippines is typically river water and in some cases groundwater. These sources are prone to elevated levels of metals and metalloids that may cause exposure of the general population when the treatment of the water is inadequate. This work presents a simple method based on EPA Method 200.8 for the determination of total concentrations of arsenic (As, cadmium (Cd and lead (Pb in drinking water using inductively coupled plasma-mass spectrometry (ICP-MS as the element-selective detector. This was applied in the determination of these elements in the water supply in Metro Manila, Philippines. The method detection limits were 0.095 μg L-1, 0.043 μg L-1, and 0.114 μg L-1 for total As, Cd and Pb, respectively.The method was validated using National Institute of Standards and Technology (NIST 1643e certified reference material for trace elements in water and determined values were 60.4 ± 0.5 μg L-1, 6.7 ± 0.1 μg L-1, and 19.6 ± 0.5 μg L-1 for As, Cd and Pb, respectively. These determined values were in good agreement with the certified values in the reference material. Analysis of actual drinking water samples showed that most samples did not exceed the limit of the Philippine drinking water standard for the elements.

  9. Investigating the Formation Process of Sn-Based Lead-Free Nanoparticles with a Chemical Reduction Method

    Directory of Open Access Journals (Sweden)

    Weipeng Zhang

    2013-01-01

    Full Text Available Nanoparticles of a promising lead-free solder alloy (Sn3.5Ag (wt.%, SnAg and Sn3.0Ag0.5Cu (wt.%, SAC were synthesized through a chemical reduction method by using anhydrous ethanol and 1,10-phenanthroline as the solvent and surfactant, respectively. To illustrate the formation process of Sn-Ag alloy based nanoparticles during the reaction, X-ray diffraction (XRD was used to investigate the phases of the samples in relation to the reaction time. Different nucleation and growth mechanisms were compared on the formation process of the synthesized nanoparticles. The XRD results revealed different reaction process compared with other researchers. There were many contributing factors to the difference in the examples found in the literature, with the main focus on the formation mechanism of crystal nuclei, the solubility and ionizability of metal salts in the solvent, the solid solubility of Cu in Ag nuclei, and the role of surfactant on the growth process. This study will help define the parameters necessary for the control of both the composition and size of the nanoparticles.

  10. Structural analysis of lead magnesium niobate using synchrotron powder X-ray diffraction and the Rietveld method.

    Science.gov (United States)

    Bhakar, Ashok; Pandey, Adityanarayan H; Singh, M N; Upadhyay, Anuj; Sinha, A K; Gupta, S M; Ganguli, Tapas

    2016-06-01

    The room-temperature synchrotron powder X-ray diffraction pattern of the single phase perovskite lead magnesium niobate (PMN) has shown significant broadening in the q range ∼ 5-7 Å(-1) compared with standard LaB6 synchrotron powder X-ray diffraction data, taken under similar conditions. This broadening/asymmetry lies mainly towards the lower 2θ side of the Bragg peaks. Attempts to fit this data with the paraelectric cubic phase (Pm\\bar 3m) and the local rhombohedral phase (R3m) corresponding to polar nanoregions (PNRs) are made using the Rietveld method. Rietveld refinements show that neither cubic (Pm\\bar 3m) nor rhombohedral (R3m) symmetry can fit this XRD pattern satisfactorily. The two-phase refinement fits the experimental data satisfactorily and suggests that the weight percentage of the PNRs is approximately 12-16% at room temperature. The unit-cell volume of these rhombohedral PNRs is approximately 0.15% larger than that of the unit cell volume of the paraelectric cubic phase.

  11. Initial interlaboratory validation of an analytical method for the determination of lead in canned tuna to be used for monitoring and regulatory purposes.

    Science.gov (United States)

    Santiago, E C; Bello, F B B

    2003-06-01

    The Association of Official Analytical Chemists (AOAC) Standard Method 972.23 (dry ashing and flame atomic absorption spectrophotometry (FAAS)), applied to the analysis of lead in tuna, was validated in three selected local laboratories to determine the acceptability of the method to both the Codex Alimentarius Commission (Codex) and the European Union (EU) Commission for monitoring lead in canned tuna. Initial validation showed that the standard AOAC method as performed in the three participating laboratories cannot satisfy the Codex/EU proposed criteria for the method detection limit for monitoring lead in fish at the present regulation level of 0.5 mg x kg(-1). Modification of the standard method by chelation/concentration of the digest solution before FAAS analysis showed that the modified method has the potential to meet Codex/EU criteria on sensitivity, accuracy and precision at the specified regulation level.

  12. Methods of thermoelectric enhancement in silicon-germanium alloy type I clathrates and in nanostructured lead chalcogenides

    Science.gov (United States)

    Martin, Joshua

    The rapid increase in thermoelectric (TE) materials R&D is a consequence of the growing need to increase energy efficiency and independence through waste heat recovery. TE materials enable the direct solid-state conversion of heat into electricity, with little maintenance, noise, or cost. In addition, these compact devices can be incorporated into existing technologies to increase the overall operating efficiency. High efficiency TE materials would enable the practical solid-state conversion of thermal to electrical energy. Optimizing the interdependent physical parameters to achieve acceptable efficiencies requires materials exhibiting a unique combination of properties. This research reports two methods of thermoelectric enhancement: lattice strain effects in silicon-germanium alloy type I clathrates and the nanostructured enhancement of lead chalcogenides. The synthesis and chemical, structural, and transport properties characterization of Ba8Ga16SixGe30-x type I clathrates with similar Ga-to-group IV element ratios but with increasing Si substitution (4 effective mass on Si substitution level, may imply a modified band structure with Si substitution. These materials were then further optimized by adjusting the Ga-to-group IV element ratios. Recent progress in a number of higher efficiency TE materials can be attributed to nanoscale enhancement. Many of these materials demonstrate increased Seebeck coefficient and decreased thermal conductivity due to the phenomenological properties of nanometer length scales. To satisfy the demands of bulk industrial applications requires additional synthesis techniques to incorporate nanostructure directly within a bulk matrix. This research investigates, for the first time, dense dimensional nanocomposites prepared by densifying nanocrystals synthesized employing a solution-phase reaction. Furthermore, the carrier concentration of the PbTe nanocomposites can be adjusted by directly doping the nanocrystals, necessary for power

  13. Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods. 4. Artificial aging of model samples of co-precipitates of lead chromate and lead sulfate.

    Science.gov (United States)

    Monico, Letizia; Janssens, Koen; Miliani, Costanza; Van der Snickt, Geert; Brunetti, Brunetto Giovanni; Cestelli Guidi, Mariangela; Radepont, Marie; Cotte, Marine

    2013-01-15

    Previous investigations about the darkening of chrome yellow pigments revealed that this form of alteration is attributable to a reduction of the original Cr(VI) to Cr(III), and that the presence of sulfur-containing compounds, most often sulfates, plays a key role during this process. We recently demonstrated that different crystal forms of chrome yellow pigments (PbCrO(4) and PbCr(1-x)S(x)O(4)) are present in paintings by Vincent van Gogh. In the present work, we show how both the chemical composition and the crystalline structure of lead chromate-based pigments influence their stability. For this purpose, oil model samples made with in-house synthesized powders of PbCrO(4) and PbCr(1-x)S(x)O(4) were artificially aged and characterized. We observed a profound darkening only for those paint models made with PbCr(1-x)S(x)O(4), rich in SO(4)(2-) (x ≥ 0.4), and orthorhombic phases (>30 wt %). Cr and S K-edge micro X-ray absorption near edge structure investigations revealed in an unequivocal manner the formation of up to about 60% of Cr(III)-species in the outer layer of the most altered samples; conversely, independent of the paint models' chemical composition, no change in the S-oxidation state was observed. Analyses employing UV-visible diffuse reflectance and Fourier transform infrared spectroscopy were performed on unaged and aged model samples in order to obtain additional information on the physicochemical changes induced by the aging treatment.

  14. Lead Test

    Science.gov (United States)

    ... Links Patient Resources For Health Professionals Subscribe Search Lead Send Us Your Feedback Choose Topic At a ... Related Content View Sources Also Known As Blood Lead Test Blood Lead Level BLL Formal Name Lead, ...

  15. Gamma/hadron segregation for a ground based imaging atmospheric Cherenkov telescope using machine learning methods: Random Forest leads

    Science.gov (United States)

    Sharma, Mradul; Nayak, Jitadeepa; Krishna Koul, Maharaj; Bose, Smarajit; Mitra, Abhas

    2014-11-01

    A detailed case study of γ-hadron segregation for a ground based atmospheric Cherenkov telescope is presented. We have evaluated and compared various supervised machine learning methods such as the Random Forest method, Artificial Neural Network, Linear Discriminant method, Naive Bayes Classifiers, Support Vector Machines as well as the conventional dynamic supercut method by simulating triggering events with the Monte Carlo method and applied the results to a Cherenkov telescope. It is demonstrated that the Random Forest method is the most sensitive machine learning method for γ-hadron segregation.

  16. An evaluation of sampling methods and supporting techniques for tackling lead in drinking water in Aberta Province

    Science.gov (United States)

    A collaborative project commenced in August 2013 with the aim of demonstrating a range of techniques that can be used in tackling the problems of lead in drinking water. The main project was completed in March 2014, with supplementary sampling exercises in mid-2014. It involved t...

  17. Applicability of linearized-theory attached-flow methods to design and analysis of flap systems at low speeds for thin swept wings with sharp leading edges

    Science.gov (United States)

    Carlson, Harry W.; Darden, Christine M.

    1987-01-01

    Low-speed experimental force and data on a series of thin swept wings with sharp leading edges and leading and trailing-edge flaps are compared with predictions made using a linearized-theory method which includes estimates of vortex forces. These comparisons were made to assess the effectiveness of linearized-theory methods for use in the design and analysis of flap systems in subsonic flow. Results demonstrate that linearized-theory, attached-flow methods (with approximate representation of vortex forces) can form the basis of a rational system for flap design and analysis. Even attached-flow methods that do not take vortex forces into account can be used for the selection of optimized flap-system geometry, but design-point performance levels tend to be underestimated unless vortex forces are included. Illustrative examples of the use of these methods in the design of efficient low-speed flap systems are included.

  18. Determination of total lead in 400 lipsticks on the U.S. market using a validated microwave-assisted digestion, inductively coupled plasma-mass spectrometric method.

    Science.gov (United States)

    Hepp, Nancy M

    2012-01-01

    In 2009, the U.S. Food and Drug Administration (FDA) published lead (Pb) content results from a small survey of 20 tube lipsticks with red shades using a validated inductively coupled plasma-mass spectrometric (ICP-MS) method developed by FDA chemists. The study was prompted by a media report suggesting that potential exposure to lead from lipsticks under conditions of ordinary use might be harmful. The FDA has since investigated the lead content of tube lipsticks by conducting an expanded survey that included a variety of shades and manufacturers, at varying prices. The purposes of the expanded survey were to ascertain the levels of lead in lipsticks sold on the U.S. market, to identify any categories of lipstick with elevated levels of lead, and to compare the results to those from the initial small survey. Four hundred lipsticks available on the U.S. market in the spring of 2010 were tested for total lead content using the FDA's validated method. The analyses were performed by a private laboratory contracted by the FDA. The maximum lead level found was 7.19 mg Pb/kg. Thirteen of the 400 lipsticks were found to contain levels greater than 3.06 mg Pb/kg, the highest amount found in the initial survey. The average lead concentration found in the expanded survey was 1.11 mg Pb/kg, which was very close to the average of 1.07 mg Pb/kg found in the initial survey. Some statistically significant associations between lead level and parent company were found. The contract requirements, testing procedures, and findings from the expanded survey are described here.

  19. 40 CFR Appendix G to Part 50 - Reference Method for the Determination of Lead in Suspended Particulate Matter Collected From...

    Science.gov (United States)

    2010-07-01

    ... the sample as follows: 7.2.1.5.1 Rinse watch glass and sides of beaker with D.I. water. 7.2.1.5.2.... 1.1 Ambient air suspended particulate matter is collected on a glass-fiber filter for 24 hours using... lead content of the sample is analyzed by atomic absorption spectrometry using an air-acetylene flame...

  20. Narrative Method of Practice Increases Curiosity & Exploration, Psychological Capital, and Personal Growth Leading to Career Clarity: A Retrospective Outcome Study

    OpenAIRE

    Mark Franklin; Basak Yanar; Rich Feller

    2015-01-01

    The paradigm in career counselling is shifting from traditional matching assessments to narrative methods. Storytelling approaches, life design principles, and evidence-based methods of practice are integrating theory into practical tools that career professionals want to use and can easily learn. Evidence of effectiveness of such methods are key to their being implemented, and broad career management variables beyond employment status need to be identified. The retrospective outcome study of...

  1. Lead Poisoning

    Science.gov (United States)

    Lead is a metal that occurs naturally in the earth's crust. Lead can be found in all parts of our ... from human activities such as mining and manufacturing. Lead used to be in paint; older houses may ...

  2. Radiochemical neutron activation analysis method for the determination of tin, arsenic, copper and antimony for the forensic comparison of bullet lead specimens

    Energy Technology Data Exchange (ETDEWEB)

    Desai, H.B.; Parthasarathy, R. (Bhabha Atomic Research Centre, Bombay (India). Analytical Chemistry Div.)

    1983-01-01

    Trace element characterization of bullet lead by instrumental neutron activation analysis (INAA) is hampered by the high spectral background due to antimony, normally present in high concentration in bullet lead. Tin is indicated to be a very useful element for characterization purposes. Beta-active /sup 121/Sn is a suitable nuclide for quantitation of tin provided it is separated in high radiochemical purity. A radiochemical procedure capable of determining tin down to 10 ppm in bullet lead, a sequential procedure for its determination along with copper, arsenic and antimony and the application of this procedure for the determination of the contents of these elements in various bullet leads are described. This method has been applied to a 'Rhinoceros shoot-out' case, referred to the authors' laboratory.

  3. Evaluation of lead levels in biological samples of mentally retarded children in different stages using advanced extraction method.

    Science.gov (United States)

    Kazi, Tasneem Gul; Shah, Faheem; Afridi, Hassan Imran; Mughal, Moina Akhtar; Naeemullah; Arain, Sadaf Sadia; Arain, Mohammad Balal

    2013-11-01

    In present study the lead (Pb) levels has been assessed by analyzing the scalp hair and blood samples of mentally retarded/intellectual disabled (MR/ID) children of both genders, age ranged 3-8 years. For comparative purpose, healthy age matched children were also selected. The cloud point extraction of Pb from digested biological samples was carried out by complexed with ammonium pyrrolidinedithiocarbamate. The complexed analyte was subsequently isolated from the aqueous matrix in the micelles of a non-ionic surfactant (Triton X-114). Dilution of the surfactant-rich phase with acidified ethanol was performed after phase separation, and the Pb content was measured by flame atomic absorption spectrometer. Factors affecting the cloud point extraction were evaluated and optimized. The proposed procedure allowed the determination of lead in certified standard and real samples with detection limits of 0.834μgL(-) and enhancement factor 55. The results were compared with those of healthy children have same age, socioeconomic status and residential areas. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. A method of predicting flow rates required to achieve anti-icing performance with a porous leading edge ice protection system

    Science.gov (United States)

    Kohlman, D. L.; Albright, A. E.

    1983-01-01

    An analytical method was developed for predicting minimum flow rates required to provide anti-ice protection with a porous leading edge fluid ice protection system. The predicted flow rates compare with an average error of less than 10 percent to six experimentally determined flow rates from tests in the NASA Icing Research Tunnel on a general aviation wing section.

  5. Modal generation of the design parameters of an elastic spacecraft by the random search method

    Science.gov (United States)

    Titov, B. A.

    A method for the modal generation of the dynamic properties of an elastic spacecraft is proposed which is based on algorithms of random search in the space of design parameters. A practical implementation of this approach is illustrated by an example. It is shown that the modal parameter generation procedure based on the random search solves the problem of parameter selection. However, as in any other method, the accuracy of the computation of matrix elements is largely determined by the initial set of permissible values and the number of random samples in determining the subgradient of the objective function.

  6. Effectiveness of silica based sol-gel microencapsulation method for odorants and flavors leading to sustainable environment.

    Science.gov (United States)

    Ashraf, Muhammad Aqeel; Khan, Aysha Masood; Ahmad, Mushtaq; Sarfraz, Maliha

    2015-01-01

    Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped active agents, thereby broadening the practical utilization of chemically unstable essential oils (EOs). Reviewing progress in the fabrication of diverse odorant and flavored sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits.

  7. Effectiveness of silica based sol-gel microencapsulation method for odorants and flavors leading to sustainable environment

    Science.gov (United States)

    Ashraf, Muhammad Aqeel; Khan, Aysha Masood; Ahmad, Mushtaq; Sarfraz, Maliha

    2015-01-01

    Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped active agents, thereby broadening the practical utilization of chemically unstable essential oils (EOs). Reviewing progress in the fabrication of diverse odorant and flavored sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits. PMID:26322304

  8. Effectiveness of silica based Sol-gel microencapsulation Method for odorants and flavours leading to sustainable Environment

    Science.gov (United States)

    Ashraf, Muhammad Aqeel; Khan, Ayesha Masood; Sarfraz, Maliha; Ahmad, Mushtaq

    2015-08-01

    Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped actives, thereby broadening the practical utilization of chemically unstable essential oils. Reviewing progress in the fabrication of diverse odorant and flavoured sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits.

  9. Effectiveness of silica based Sol-gel microencapsulation Method for odorants and flavours leading to sustainable Environment

    Directory of Open Access Journals (Sweden)

    Muhammad Aqeel eAshraf

    2015-08-01

    Full Text Available Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol–gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol–gel SiO2 is non-toxic and safe, whereas the sol–gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped actives, thereby broadening the practical utilization of chemically unstable essential oils. Reviewing progress in the fabrication of diverse odorant and flavoured sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits.

  10. A Mixed Methods Study: Principals' Perceived Leadership Styles and Ability to Lead during a School Violence Crisis

    Science.gov (United States)

    Henderson, Joyce Herod

    2013-01-01

    Our schools are considered a place of safety for learning, however, the unfortunate reality is that schools may face crises and violence. Leadership styles vary among school leaders and provide the framework for handling daily challenges. This mixed-methods research design was used to investigate the individual leadership styles of public school…

  11. Field assessment of treatment efficacy by three methods of phosphoric acid application in lead-contaminated urban soil.

    Science.gov (United States)

    Yang, John; Mosby, David

    2006-07-31

    In situ soil treatment using phosphoric acid (H(3)PO(4)) may be an effective remedial technology for immobilizing soil Pb and reducing Pb risk to human health and ecosystem. The treatment efficacy of three H(3)PO(4) application methods was assessed in a smelter-contaminated urban soil located in the Jasper County Superfund Site, Missouri. Soil, with an average of 3529 mg Pb kg(-1) and in the 2- by 4-m plot size, was treated with H(3)PO(4) at a rate of 10 g P kg(-1) in four replicates by each of three methods: rototilling; surface application; pressure injection. Three soil cores, 2.5-cm diameter and 30-cm long, were taken from each plot before and 90 days after treatment and analyzed for soluble P, bioaccessible Pb and solid-Pb speciation. Applications of H(3)PO(4) induced the heterogeneity of soluble P in soil, with the highest concentrations in the surface. Three application methods mixed the H(3)PO(4) more effectively in the horizontals than the verticals of treated soil zone. The H(3)PO(4) applications significantly reduced Pb bioaccessibility in the soil, which was influenced by the concentrations of soil soluble P and solid-Pb species. The risk reductions of soil Pb were achieved by formation of pyromorphites or pyromorphite-like minerals. The rototilling appears to be the most effective treatment method in context of the homogeneity of soluble P and the reduction of Pb bioaccessibility in treated soil.

  12. Influence of digestion methods on the recovery of Iron, Zinc, Nickel, Chromium, Cadmium and Lead contents in 11 organic residues

    Directory of Open Access Journals (Sweden)

    Thalita Fernanda Abbruzzini

    2014-02-01

    Full Text Available There are currently many devices and techniques to quantify trace elements (TEs in various matrices, but their efficacy is dependent on the digestion methods (DMs employed in the opening of such matrices which, although "organic", present inorganic components which are difficult to solubilize. This study was carried out to evaluate the recovery of Fe, Zn, Cr, Ni, Cd and Pb contents in samples of composts and cattle, horse, chicken, quail, and swine manures, as well as in sewage sludges and peat. The DMs employed were acid digestion in microwaves with HNO3 (EPA 3051A; nitric-perchloric digestion with HNO3 + HClO4 in a digestion block (NP; dry ashing in a muffle furnace and solubilization of residual ash in nitric acid (MDA; digestion by using aqua regia solution (HCl:HNO3 in the digestion block (AR; and acid digestion with HCl and HNO3 + H2O2 (EPA 3050. The dry ashing method led to the greatest recovery of Cd in organic residues, but the EPA 3050 protocol can be an alternative method for the same purpose. The dry ashing should not be employed to determine the concentration of Cr, Fe, Ni, Pb and Zn in the residues. Higher Cr and Fe contents are recovered when NP and EPA 3050 are employed in the opening of organic matrices. For most of the residues analyzed, AR is the most effective method for recovering Ni. Microwave-assisted digestion methods (EPA3051 and 3050 led to the highest recovery of Pb. The choice of the DM that provides maximum recovery of Zn depends on the organic residue and trace element analyzed.

  13. Lead poisoning

    Science.gov (United States)

    ... or dust from lead-based paint. Toys and furniture painted before 1976. Painted toys and decorations made ... by decades of car exhaust or years of house paint scrapings. Lead is more common in soil ...

  14. Lead Poisoning

    Science.gov (United States)

    ... a hard, durable surface. In 1977, federal regulations banned lead from paint for general use. But homes ... OTHERS: Lead has recently been found in some plastic mini-blinds and vertical blinds which were made ...

  15. Relational Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    This first chapter presents the exploratory and curious approach to leading as relational processes – an approach that pervades the entire book. We explore leading from a perspective that emphasises the unpredictable challenges and triviality of everyday life, which we consider an interesting......, relevant and realistic way to examine leading. The chapter brings up a number of concepts and contexts as formulated by researchers within the field, and in this way seeks to construct a first understanding of relational leading....

  16. Incorporating Virtual Reactions into a Logic-based Ligand-based Virtual Screening Method to Discover New Leads

    Science.gov (United States)

    Reynolds, Christopher R; Muggleton, Stephen H; Sternberg, Michael J E

    2015-01-01

    The use of virtual screening has become increasingly central to the drug development pipeline, with ligand-based virtual screening used to screen databases of compounds to predict their bioactivity against a target. These databases can only represent a small fraction of chemical space, and this paper describes a method of exploring synthetic space by applying virtual reactions to promising compounds within a database, and generating focussed libraries of predicted derivatives. A ligand-based virtual screening tool Investigational Novel Drug Discovery by Example (INDDEx) is used as the basis for a system of virtual reactions. The use of virtual reactions is estimated to open up a potential space of 1.21×1012 potential molecules. A de novo design algorithm known as Partial Logical-Rule Reactant Selection (PLoRRS) is introduced and incorporated into the INDDEx methodology. PLoRRS uses logical rules from the INDDEx model to select reactants for the de novo generation of potentially active products. The PLoRRS method is found to increase significantly the likelihood of retrieving molecules similar to known actives with a p-value of 0.016. Case studies demonstrate that the virtual reactions produce molecules highly similar to known actives, including known blockbuster drugs. PMID:26583052

  17. Incorporating Virtual Reactions into a Logic-based Ligand-based Virtual Screening Method to Discover New Leads.

    Science.gov (United States)

    Reynolds, Christopher R; Muggleton, Stephen H; Sternberg, Michael J E

    2015-09-01

    The use of virtual screening has become increasingly central to the drug development pipeline, with ligand-based virtual screening used to screen databases of compounds to predict their bioactivity against a target. These databases can only represent a small fraction of chemical space, and this paper describes a method of exploring synthetic space by applying virtual reactions to promising compounds within a database, and generating focussed libraries of predicted derivatives. A ligand-based virtual screening tool Investigational Novel Drug Discovery by Example (INDDEx) is used as the basis for a system of virtual reactions. The use of virtual reactions is estimated to open up a potential space of 1.21×1012 potential molecules. A de novo design algorithm known as Partial Logical-Rule Reactant Selection (PLoRRS) is introduced and incorporated into the INDDEx methodology. PLoRRS uses logical rules from the INDDEx model to select reactants for the de novo generation of potentially active products. The PLoRRS method is found to increase significantly the likelihood of retrieving molecules similar to known actives with a p-value of 0.016. Case studies demonstrate that the virtual reactions produce molecules highly similar to known actives, including known blockbuster drugs.

  18. Do young novice drivers overestimate their driving skills more than experienced drivers? Different methods lead to different conclusions.

    Science.gov (United States)

    De Craen, S; Twisk, D A M; Hagenzieker, M P; Elffers, H; Brookhuis, K A

    2011-09-01

    In this study we argue that drivers have to make an assessment of their own driving skills, in order to sufficiently adapt to their task demands in traffic. There are indications that drivers in general, but novice drivers in particular, overestimate their driving skills. However, study results differ on the subject of self-assessment of skills. The objectives of this paper are (1) to study whether novice drivers indeed overestimate their driving skills more than experienced drivers; and (2) to evaluate the influence of the method to measure self-assessment of skills (i.e. comparison to 'average' and 'peer' driver versus independent measures of own performance). The results show that the conclusion of whether novice drivers overestimate their driving skills is highly affected by the method chosen to measure self-assessment of skills. When drivers are asked to compare themselves to the average and peer driver, we can conclude that novice drivers are not as optimistic about their driving skills as has been reported in the past. They seem to recognize that they are not as skilled (yet) as the average driver. However, when comparing their self-assessment with their actual behaviour there are indications that they overestimate their driving skills. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Development of a simple method for the determination of lead in lipstick using alkaline solubilization and graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Soares, Aline Rodrigues; Nascentes, Clésia Cristina

    2013-02-15

    A simple method was developed for determining the total lead content in lipstick samples by graphite furnace atomic absorption spectrometry (GFAAS) after treatment with tetramethylammonium hydroxide (TMAH). Multivariate optimization was used to establish the optimal conditions of sample preparation. The graphite furnace heating program was optimized through pyrolysis and atomization curves. An aliquot containing approximately 50mg of the sample was mixed with TMAH and heated in a water bath at 60°C for 60 min. Using Nb as the permanent modifier and Pd as the chemical modifier, the optimal temperatures were 900°C and 1800°C for pyrolysis and atomization, respectively. Under optimum conditions, the working range was from 1.73 to 50.0 μg L(-1), with detection and quantification limits of 0.20 and 0.34 μg g(-1), respectively. The precision was evaluated under conditions of repeatability and intermediate precision and showed standard deviations of 2.37%-4.61% and 4.93%-9.75%, respectively. The % recovery ranged from 96.2% to 109%, and no significant differences were found between the results obtained using the proposed method and the microwave decomposition method for real samples. Lead was detected in 21 tested lipstick samples; the lead content in these samples ranged from 0.27 to 4.54 μg g(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Fragment Molecular Orbital Method Applied to Lead Optimization of Novel Interleukin-2 Inducible T-Cell Kinase (ITK) Inhibitors.

    Science.gov (United States)

    Heifetz, Alexander; Trani, Giancarlo; Aldeghi, Matteo; MacKinnon, Colin H; McEwan, Paul A; Brookfield, Frederick A; Chudyk, Ewa I; Bodkin, Mike; Pei, Zhonghua; Burch, Jason D; Ortwine, Daniel F

    2016-05-12

    Inhibition of inducible T-cell kinase (ITK), a nonreceptor tyrosine kinase, may represent a novel treatment for allergic asthma. In our previous reports, we described the discovery of sulfonylpyridine (SAP), benzothiazole (BZT), indazole (IND), and tetrahydroindazole (THI) series as novel ITK inhibitors and how computational tools such as dihedral scans and docking were used to support this process. X-ray crystallography and modeling were applied to provide essential insight into ITK-ligand interactions. However, "visual inspection" traditionally used for the rationalization of protein-ligand affinity cannot always explain the full complexity of the molecular interactions. The fragment molecular orbital (FMO) quantum-mechanical (QM) method provides a complete list of the interactions formed between the ligand and protein that are often omitted from traditional structure-based descriptions. FMO methodology was successfully used as part of a rational structure-based drug design effort to improve the ITK potency of high-throughput screening hits, ultimately delivering ligands with potency in the subnanomolar range.

  1. Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics.

    Science.gov (United States)

    Isobe, Gaku; Maeda, Takafumi; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

    2014-02-01

    (K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders.

  2. The prospective evaluation of safety and success of a new method of introducing percutaneous paddle leads and complex arrays with an epidural access system.

    Science.gov (United States)

    Deer, Timothy; Bowman, Richard; Schocket, Sandford Matthew; Kim, Christopher; Ranson, Matthew; Amirdelfan, Kasra; Raso, Louis

    2012-01-01

      Spinal cord stimulation (SCS) has become a mainstay in the continuum of care for patients suffering from chronic neuropathic pain of the trunk and limbs. Options for placing these devices have included a percutaneous method of using an epidural needle to place a cylindrical (percutaneous) lead to stimulate the spinal cord, or an open laminotomy method for placing a paddle lead at the location of the surgical decompression of the laminae. Both of these methods have been successful in a high percentage of patients, but neither have been ideal. Limitations of the percutaneous leads have been inefficiency of power delivery, inability to achieve desired depth of stimulation in the spinal cord, occasional lead migration and difficulty covering complex pain patterns. Limitations of the paddle lead have been the need for surgical laminotomy, inability to steer the lead once placed, limits on placement in the vicinity of the surgical decompression, and a perceived risk of increased bleeding and trauma to the tissue. These factors have led many minimally invasive spine specialists to seek new options for SCS. This paper presents the initial US experience with a newly approved device to place both paddle leads, and multi-lead arrays into the epidural space via a percutaneous Seldinger-guided approach through a single needle placement. We will both describe the technique and review the outcomes of some of the early cases.   After Investigational Review Board clearance, patients consented to data collection in a prospective fashion regarding the use of a new percutaneous epidural introducer (Epiducer, St. Jude Neurological, Minneapolis, MN, USA) to place paddle leads and complex lead arrays. The patients underwent education regarding expectations and risks of the procedure consistent with our normal preoperative period. Patients underwent preoperative anesthesia screening and proper testing as outlined by the Joint Commission on Hospital Accreditation, and were given the

  3. Technology-based vs. traditional instruction. A comparison of two methods for teaching the skill of performing a 12-lead ECG.

    Science.gov (United States)

    Jeffries, Pamela R; Woolf, Shirley; Linde, Beverly

    2003-01-01

    The purpose of this study was to compare the effectiveness of an interactive, multimedia CD-ROM with traditional methods of teaching the skill of performing a 12-lead ECG. A randomized pre/posttest experimental design was used. Seventy-seven baccalaureate nursing students in a required, senior-level critical-care course at a large midwestern university were recruited for the study. Two teaching methods were compared. The traditional method included a self-study module, a brief lecture and demonstration by an instructor, and hands-on experience using a plastic manikin and a real 12-lead ECG machine in the learning laboratory. The second method covered the same content using an interactive, multimedia CD-ROM embedded with virtual reality and supplemented with a self-study module. There were no significant (p new and potentially more cost-effective teaching methods and their effects on student learning outcomes and behaviors, including the transfer of skill acquisition via a computer simulation to a real patient.

  4. Development and application of an inhalation bioaccessibility method (IBM) for lead in the PM10 size fraction of soil.

    Science.gov (United States)

    Boisa, Ndokiari; Elom, Nwabueze; Dean, John R; Deary, Michael E; Bird, Graham; Entwistle, Jane A

    2014-09-01

    An approach for assessing the inhalation bioaccessibility of Pb in the PM10 size fraction is presented, using an in vitro simulated epithelial lung fluid to represent the extracellular environment of the lung. The developed inhalation bioaccessibility method (IBM) is applied to a range of urban surface soils and mining wastes obtained from Mitrovica, Kosovo, a site where impacts upon human health following exposure to Pb have been internationally publicised. All Pb determinations were undertaken by inductively coupled plasma mass spectrometry (ICP-MS). The pseudo-total concentration of Pb (microwave acid digestion using aqua-regia) varied between matrices: smelter (20,900-72,800mgkg(-1)), topsoil (274-13,700mgkg(-1)), and tailings (2990mgkg(-1)-25,300mgkg(-1)). The in vitro inhalation bioaccessibility was typically several orders of magnitude lower: smelter (7.0-965mgkg(-1)), topsoil (9.8-1060mgkg(-1)), and tailings (0.7mgkg(-1)-49.2mgkg(-1)). The % inhalation bioaccessibility ranged from 0.02 to 11.0%, with the higher inhalation bioaccessible Pb concentrations being observed for samples from the Bosniak Mahalla area of Mitrovica (an area proposed for the relocation of internally displaced peoples). The estimated inhalation dose (for adults) calculated from the PM10 pseudo-total Pb concentration ranged from 0.369 to 1.284μgkg(-1)BWday(-1) (smelter), 0.005-0.242μgkg(-1)BWday(-1) (topsoil), and 0.053-0.446μgkg(-1)BWday(-1) (tailings). When daily inhalation doses were calculated using the bioaccessible Pb concentration the modelled exposure doses were much lower: smelter (0.0001-0.0170μgkg(-1)BWday(-1)), topsoil (0.0002-0.0187μgkg(-1)BWday(-1)) and tailings (0.0001-0.0009μgkg(-1)BWday(-1)). Modelled for the neutral pH conditions of the interstitial lung environment, the results indicate a low potential inhalation bioaccessibility for Pb in these samples. Given the already elevated environmental Pb burden experienced by the local population, where significant

  5. A sensitive fluorescence anisotropy method for detection of lead (II) ion by a G-quadruplex-inducible DNA aptamer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dapeng [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Yin, Lei; Meng, Zihui [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing, 100081 (China); Yu, Anchi [Department of Chemistry, Renmin University of China, Beijing, 100872 (China); Guo, Lianghong [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Wang, Hailin, E-mail: hlwang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China)

    2014-02-17

    Graphical abstract: -- Highlights: •A fluorescence anisotropy approach for detection of Pb{sup 2+} was developed. •The strategy was based on binding-induced allosteric conformational change of aptamer probe. •The sensing mechanism was established by testing the photoinduced electron transfer interaction. -- Abstract: Sensitive and selective detection of Pb{sup 2+} is of great importance to both human health and environmental protection. Here we propose a novel fluorescence anisotropy (FA) approach for sensing Pb{sup 2+} in homogeneous solution by a G-rich thrombin binding aptamer (TBA). The TBA labeled with 6-carboxytetramethylrhodamine (TMR) at the seventh thymine nucleotide was used as a fluorescent probe for signaling Pb{sup 2+}. It was found that the aptamer probe had a high FA in the absence of Pb{sup 2+}. This is because the rotation of TMR is restricted by intramolecular interaction with the adjacent guanine bases, which results in photoinduced electron transfer (PET). When the aptamer probe binds to Pb{sup 2+} to form G-quadruplex, the intramolecular interaction should be eliminated, resulting in faster rotation of the fluorophore TMR in solution. Therefore, FA of aptamer probe is expected to decrease significantly upon binding to Pb{sup 2+}. Indeed, we observed a decrease in FA of aptamer probe upon Pb{sup 2+} binding. Circular dichroism, fluorescence spectra, and fluorescence lifetime measurement were used to verify the reliability and reasonability of the sensing mechanism. By monitoring the FA change of the aptamer probe, we were able to real-time detect binding between the TBA probe and Pb{sup 2+}. Moreover, the aptamer probe was exploited as a recognition element for quantification of Pb{sup 2+} in homogeneous solution. The change in FA showed a linear response to Pb{sup 2+} from 10 nM to 2.0 μM, with 1.0 nM limit of detection. In addition, this sensing system exhibited good selectivity for Pb{sup 2+} over other metal ions. The method is simple

  6. Comparison of occupational exposure assessment methods in a case-control study of lead, genetic susceptibility and risk of adult brain tumors

    Science.gov (United States)

    Bhatti, Parveen; Stewart, Patricia A.; Linet, Martha S.; Blair, Aaron; Inskip, Peter D.; Rajaraman, Preetha

    2013-01-01

    Objectives There is great interest in evaluating gene-environment interactions with chemical exposures, but exposure assessment poses a unique challenge in case-control studies. Expert assessment of detailed work history data is usually considered the best approach, but it is a laborious and time-consuming process. We set out to determine if a less intensive method of exposure assessment (a job exposure matrix [JEM]) would produce similar results to a previous analysis that found evidence of effect modification between expert assessed-lead exposure and risk of brain tumors by a single nucleotide polymorphism in the ALAD gene (rs1800435). Methods We used data from a study of 355 patients with glioma, 151 patients with meningioma and 505 controls. Logistic regression models were used to examine associations between brain tumor risk and lead exposure and effect modification by genotype. We evaluated Cohen’s kappa, sensitivity and specificity for the JEM compared to the expert-assessed exposure metrics. Results Although effect estimates were imprecise and driven by a small number of cases, we found evidence of effect modification between lead exposure and ALAD genotype when using expert- but not JEM-derived lead exposure estimates. Kappa values indicated only modest agreement (exposure metrics, with the JEM indicating high specificity (~0.9) but poor sensitivity (~0.5). Disagreement between the two methods was generally due to having additional information in the detailed work history. Conclusion These results provide preliminary evidence suggesting that high quality exposure data are likely to improve the ability to detect genetic effect modification. PMID:20798009

  7. [Unification of methods for determining the trace quantities of lead, zinc, sodium and potassium ions in the assessment of drinking water adn transfusion fluid quality].

    Science.gov (United States)

    Popkov, V A; Golovina, N V; Evgrafov, A A

    2001-01-01

    The results of long-term studies made by the Department of General Chemistry, I. M. Sechenov Moscow Medical Academy, that deals with unification of methods for determining some ions of metals (lead, zinc, sodium, and potassium) in the assessment of the quality of drinking water and transfusion fluids are summarized. A procedure was developed to determine the trace impurities of zinc, lead, and silver by atomic absorption spectrometry (AAS) by using sorption concentration. C-80-2-aminothiazole, a new sorbent synthesized at the Research Institute of Polymers, was used to detect these ions in the drinking water. With regards to the chosen optimal conditions, drinking water samples were analyzed via their direct spraying in the air-acetylene flame. The prior sorption concentration determined drinking water zinc and lead ions in the concentrations equal to or less than their permissible dose concentrations. The studies indicated that the used methods to determine the trace quantities of metals in the drinking water and aqueous solutions show a high sensitivity, rapidity, simplicity of sample preparation.

  8. Separate base usages of genes located on the leading and lagging strands in Chlamydia muridarum revealed by the Z curve method

    Directory of Open Access Journals (Sweden)

    Yu Xiu-Juan

    2007-10-01

    Full Text Available Abstract Background The nucleotide compositional asymmetry between the leading and lagging strands in bacterial genomes has been the subject of intensive study in the past few years. It is interesting to mention that almost all bacterial genomes exhibit the same kind of base asymmetry. This work aims to investigate the strand biases in Chlamydia muridarum genome and show the potential of the Z curve method for quantitatively differentiating genes on the leading and lagging strands. Results The occurrence frequencies of bases of protein-coding genes in C. muridarum genome were analyzed by the Z curve method. It was found that genes located on the two strands of replication have distinct base usages in C. muridarum genome. According to their positions in the 9-D space spanned by the variables u1 – u9 of the Z curve method, K-means clustering algorithm can assign about 94% of genes to the correct strands, which is a few percent higher than those correctly classified by K-means based on the RSCU. The base usage and codon usage analyses show that genes on the leading strand have more G than C and more T than A, particularly at the third codon position. For genes on the lagging strand the biases is reverse. The y component of the Z curves for the complete chromosome sequences show that the excess of G over C and T over A are more remarkable in C. muridarum genome than in other bacterial genomes without separating base and/or codon usages. Furthermore, for the genomes of Borrelia burgdorferi, Treponema pallidum, Chlamydia muridarum and Chlamydia trachomatis, in which distinct base and/or codon usages have been observed, closer phylogenetic distance is found compared with other bacterial genomes. Conclusion The nature of the strand biases of base composition in C. muridarum is similar to that in most other bacterial genomes. However, the base composition asymmetry between the leading and lagging strands in C. muridarum is more significant than that in

  9. Lead Toxicity

    Science.gov (United States)

    ... blue-gray metal that is mined from the earth’s crust. • Lead has been used for many industrial ... including the kidneys, heart, and reproductive system, • Pregnant women should know that the developing fetus is very ...

  10. Lead Poisoning

    Science.gov (United States)

    ... has also been associated with juvenile delinquency and criminal behavior. In adults, lead can increase blood pressure ... and-forth manner, but rather from left to right (or vise-versa), or from the top of ...

  11. Lead Test

    Science.gov (United States)

    ... poison you. Most lead is present as an inorganic compound and does not move well through the ... D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 474. Wu, A. (© ...

  12. Examining Public Perceptions about Lead in School Drinking Water: A Mixed-Methods Analysis of Twitter Response to an Environmental Health Hazard.

    Science.gov (United States)

    Ekenga, Christine C; McElwain, Cora-Ann; Sprague, Nadav

    2018-01-20

    Exposure to lead has long been a community health concern in St. Louis, Missouri. The objective of this study was to examine public response to reports of elevated lead levels in school drinking water in St. Louis, Missouri via Twitter, a microblogging platform with over 320 million active users. We used a mixed-methods design to examine Twitter user status updates, known as "tweets," from 18 August to 31 December 2016. The number of tweets each day was recorded, and Twitter users were classified into five user types (General Public, Journalist/News, Health Professional/Academic, Politician/Government Official, and Non-Governmental Organization). A total of 492 tweets were identified during the study period. The majority of discourse on Twitter occurred during the two-week period after initial media reports and was driven by members of the General Public. Thematic analysis of tweets revealed four themes: Information Sharing, Health Concerns, Sociodemographic Disparities, and Outrage. Twitter users characterized lead in school drinking water as an issue of environmental inequity. The findings of this study provide evidence that social media platforms can be utilized as valuable tools for public health researchers and practitioners to gauge public sentiment about environmental health issues, identify emerging community concerns, and inform future communication and research strategies regarding environmental health hazards.

  13. On the Application of Iterative Methods of Nondifferentiable Optimization to Some Problems of Approximation Theory

    Directory of Open Access Journals (Sweden)

    Stefan M. Stefanov

    2014-01-01

    Full Text Available We consider the data fitting problem, that is, the problem of approximating a function of several variables, given by tabulated data, and the corresponding problem for inconsistent (overdetermined systems of linear algebraic equations. Such problems, connected with measurement of physical quantities, arise, for example, in physics, engineering, and so forth. A traditional approach for solving these two problems is the discrete least squares data fitting method, which is based on discrete l2-norm. In this paper, an alternative approach is proposed: with each of these problems, we associate a nondifferentiable (nonsmooth unconstrained minimization problem with an objective function, based on discrete l1- and/or l∞-norm, respectively; that is, these two norms are used as proximity criteria. In other words, the problems under consideration are solved by minimizing the residual using these two norms. Respective subgradients are calculated, and a subgradient method is used for solving these two problems. The emphasis is on implementation of the proposed approach. Some computational results, obtained by an appropriate iterative method, are given at the end of the paper. These results are compared with the results, obtained by the iterative gradient method for the corresponding “differentiable” discrete least squares problems, that is, approximation problems based on discrete l2-norm.

  14. Ecotoxicology: Lead

    Science.gov (United States)

    Scheuhammer, A.M.; Beyer, W.N.; Schmitt, C.J.; Jorgensen, Sven Erik; Fath, Brian D.

    2008-01-01

    Lead (Pb) is a naturally occurring metallic element; trace concentrations are found in all environmental media and in all living things. However, certain human activities, especially base metal mining and smelting; combustion of leaded gasoline; the use of Pb in hunting, target shooting, and recreational angling; the use of Pb-based paints; and the uncontrolled disposal of Pb-containing products such as old vehicle batteries and electronic devices have resulted in increased environmental levels of Pb, and have created risks for Pb exposure and toxicity in invertebrates, fish, and wildlife in some ecosystems.

  15. Leading men

    DEFF Research Database (Denmark)

    Bekker-Nielsen, Tønnes

    2016-01-01

    Through a systematic comparison of c. 50 careers leading to the koinarchate or high priesthood of Asia, Bithynia, Galatia, Lycia, Macedonia and coastal Pontus, as described in funeral or honorary inscriptions of individual koinarchs, it is possible to identify common denominators but also disting...

  16. Who Leads China's Leading Universities?

    Science.gov (United States)

    Huang, Futao

    2017-01-01

    This study attempts to identify the major characteristics of two different groups of institutional leaders in China's leading universities. The study begins with a review of relevant literature and theory. Then, there is a brief introduction to the selection of party secretaries, deputy secretaries, presidents and vice presidents in leading…

  17. Method and plant for the recovery of plastic-free lead products from used accumulators. Verfahren und Anlage zur Gewinnung von kunststoff-freien Bleiprodukten aus Altakkumulatoren

    Energy Technology Data Exchange (ETDEWEB)

    Farahmand, A.

    1982-11-04

    For the recovery of lead from used batteries it is important that lead-containing components such as metallic lead, lead oxide and lead sulphate are carefully separated from the remaining components, such as battery-casing material comprising hard rubber, polystyrol, polyethylene, polypropylene and PVC-parts, since these plastics seriously inhibit further pyrometallurgical processing. This problem has been solved by treating the plastic-containing fine lead slurry in a spiral grader with a large trough in which the lead slurry suspended in heavy medium is sorted into a specific heavy plastic-free lead product and specific light plastic components, without the need for a hydroclone. The comparatively dry plastic free lead slurry thus obtained can be further pyrometallurgically processed without difficulty.

  18. Cochrane Rapid Reviews Methods Group to play a leading role in guiding the production of informed high-quality, timely research evidence syntheses

    Directory of Open Access Journals (Sweden)

    Chantelle Garritty

    2016-10-01

    Full Text Available Abstract Background Policymakers and healthcare stakeholders are increasingly seeking evidence to inform the policymaking process, and often use existing or commissioned systematic reviews to inform decisions. However, the methodologies that make systematic reviews authoritative take time, typically 1 to 2 years to complete. Outside the traditional SR timeline, “rapid reviews” have emerged as an efficient tool to get evidence to decision-makers more quickly. However, the use of rapid reviews does present challenges. To date, there has been limited published empirical information about this approach to compiling evidence. Thus, it remains a poorly understood and ill-defined set of diverse methodologies with various labels. In recent years, the need to further explore rapid review methods, characteristics, and their use has been recognized by a growing network of healthcare researchers, policymakers, and organizations, several with ties to Cochrane, which is recognized as representing an international gold standard for high-quality, systematic reviews. Purpose In this commentary, we introduce the newly established Cochrane Rapid Reviews Methods Group developed to play a leading role in guiding the production of rapid reviews given they are increasingly employed as a research synthesis tool to support timely evidence-informed decision-making. We discuss how the group was formed and outline the group’s structure and remit. We also discuss the need to establish a more robust evidence base for rapid reviews in the published literature, and the importance of promoting registration of rapid review protocols in an effort to promote efficiency and transparency in research. Conclusion As with standard systematic reviews, the core principles of evidence-based synthesis should apply to rapid reviews in order to minimize bias to the extent possible. The Cochrane Rapid Reviews Methods Group will serve to establish a network of rapid review stakeholders

  19. A Green Preconcentration Method for Determination of Cobalt and Lead in Fresh Surface and Waste Water Samples Prior to Flame Atomic Absorption Spectrometry

    Science.gov (United States)

    Naeemullah; Kazi, Tasneem Gul; Shah, Faheem; Afridi, Hassan Imran; Khan, Sumaira; Arian, Sadaf Sadia; Brahman, Kapil Dev

    2012-01-01

    Cloud point extraction (CPE) has been used for the preconcentration and simultaneous determination of cobalt (Co) and lead (Pb) in fresh and wastewater samples. The extraction of analytes from aqueous samples was performed in the presence of 8-hydroxyquinoline (oxine) as a chelating agent and Triton X-114 as a nonionic surfactant. Experiments were conducted to assess the effect of different chemical variables such as pH, amounts of reagents (oxine and Triton X-114), temperature, incubation time, and sample volume. After phase separation, based on the cloud point, the surfactant-rich phase was diluted with acidic ethanol prior to its analysis by the flame atomic absorption spectrometry (FAAS). The enhancement factors 70 and 50 with detection limits of 0.26 μg L−1 and 0.44 μg L−1 were obtained for Co and Pb, respectively. In order to validate the developed method, a certified reference material (SRM 1643e) was analyzed and the determined values obtained were in a good agreement with the certified values. The proposed method was applied successfully to the determination of Co and Pb in a fresh surface and waste water sample. PMID:23227429

  20. A Green Preconcentration Method for Determination of Cobalt and Lead in Fresh Surface and Waste Water Samples Prior to Flame Atomic Absorption Spectrometry

    Directory of Open Access Journals (Sweden)

    Naeemullah

    2012-01-01

    Full Text Available Cloud point extraction (CPE has been used for the preconcentration and simultaneous determination of cobalt (Co and lead (Pb in fresh and wastewater samples. The extraction of analytes from aqueous samples was performed in the presence of 8-hydroxyquinoline (oxine as a chelating agent and Triton X-114 as a nonionic surfactant. Experiments were conducted to assess the effect of different chemical variables such as pH, amounts of reagents (oxine and Triton X-114, temperature, incubation time, and sample volume. After phase separation, based on the cloud point, the surfactant-rich phase was diluted with acidic ethanol prior to its analysis by the flame atomic absorption spectrometry (FAAS. The enhancement factors 70 and 50 with detection limits of 0.26 μg L−1 and 0.44 μg L−1 were obtained for Co and Pb, respectively. In order to validate the developed method, a certified reference material (SRM 1643e was analyzed and the determined values obtained were in a good agreement with the certified values. The proposed method was applied successfully to the determination of Co and Pb in a fresh surface and waste water sample.

  1. An improved partial bundle method for linearly constrained minimax problems

    Directory of Open Access Journals (Sweden)

    Chunming Tang

    2016-02-01

    Full Text Available In this paper, we propose an improved partial bundle method for solving linearly constrained minimax problems. In order to reduce the number of component function evaluations, we utilize a partial cutting-planes model to substitute for the traditional one. At each iteration, only one quadratic programming subproblem needs to be solved to obtain a new trial point. An improved descent test criterion is introduced to simplify the algorithm. The method produces a sequence of feasible trial points, and ensures that the objective function is monotonically decreasing on the sequence of stability centers. Global convergence of the algorithm is established. Moreover, we utilize the subgradient aggregation strategy to control the size of the bundle and therefore overcome the difficulty of computation and storage. Finally, some preliminary numerical results show that the proposed method is effective.

  2. Multi-step constant-current charging method for electric vehicle, valve-regulated, lead/acid batteries during night time for load-levelling

    Energy Technology Data Exchange (ETDEWEB)

    Ikeya, Tomohiko; Mita, Yuichi; Ishihara, Kaoru [Central Research Inst. of Electric Power Industry, Tokyo (Japan); Sawada, Nobuyuki [Hokkaido Electric Power, Sapporo (Japan); Takagi, Sakae; Murakami, Jun-ichi [Tohoku Electric Power, Sendai (Japan); Kobayashi, Kazuyuki [Tokyo Electric Power, Yokohama (Japan); Sakabe, Tetsuya [Chubu Electric Power, Nagoya (Japan); Kousaka, Eiichi [Hokuriku Electric Power, Toyama (Japan); Yoshioka, Haruki [The Kansai Electric Power, Osaka (Japan); Kato, Satoru [The Chugoku Electric Power, Hiroshima (Japan); Yamashita, Masanori [Shikoku Research Inst., Takamatsu (Japan); Narisoko, Hayato [The Okinawa Electric Power, Naha (Japan); Nishiyama, Kazuo [The Central Electric Power Council, Tokyo (Japan); Adachi, Kazuyuki [Kyushu Electric Power, Fukuoka (Japan)

    1998-09-01

    For the popularization of electric vehicles (EVs), the conditions for charging EV batteries with available current patterns should allow complete charging in a short time, i.e., less than 5 to 8 h. Therefore, in this study, a new charging condition is investigated for the EV valve-regulated lead/acid battery system, which should allow complete charging of EV battery systems with multi-step constant currents in a much shorter time with longer cycle life and higher energy efficiency compared with two-step constant-current charging. Although a high magnitude of the first current in the two-step constant-current method prolongs cycle life by suppressing the softening of positive active material, too large a charging current magnitude degrades cells due to excess internal evolution of heat. A charging current magnitude of approximately 0.5 C is expected to prolong cycle life further. Three-step charging could also increase the magnitude of charging current in the first step without shortening cycle life. Four-or six-step constant-current methods could shorten the charging time to less than 5 h, as well as yield higher energy efficiency and enhanced cycle life of over 400 cycles compared with two-step charging with the first step current of 0.5 C. Investigation of the degradation mechanism of the batteries revealed that the conditions of multi-step constant-current charging suppressed softening of positive active material and sulfation of negative active material, but, unfortunately, advanced the corrosion of the grids in the positive plates. By adopting improved grids and cooling of the battery system, the multistep constant-current method may enhance the cycle life. (orig.)

  3. Determination of total lead in lipstick: development and validation of a microwave-assisted digestion, inductively coupled plasma-mass spectrometric method.

    Science.gov (United States)

    Hepp, Nancy M; Mindak, William R; Cheng, John

    2009-01-01

    Recent reports describing the presence of lead (Pb) in lipsticks have suggested that, under ordinary use, the potential amount of Pb exposure is harmful. To permit independent assessment of the Pb contamination, a method for determining total Pb in lipstick using microwave-assisted digestion and analysis employing inductively coupled plasma-mass spectrometry (ICP-MS) was developed and validated. Since lipsticks may contain fats, oils, pigments, dyes, and minerals, several reference materials (RM) were analyzed, including coal, wear metals in oil, organic Pb in oil, milk powder, and estuarine sediment. With the exception of the RM with mineral content (estuarine sediment), complete recovery of Pb from the RMs was obtained by simple nitric acid (HNO(3)) digestion. Complete recovery of Pb from estuarine sediment was achieved only when hydrofluoric acid (HF) was added to the digestion mix, followed by treatment with excess boric acid (H(3)BO(3)) to neutralize the HF and to dissolve insoluble fluorides. Commercial lipsticks were tested for total Pb by the validated method. The detection limit was estimated to be 0.04 microg Pb/g. The average value obtained for the lipsticks was 1.07 microg/g. Undigested material was present in some lipstick digests when only HNO(3) was used, and generally lower Pb values were obtained. All of the Pb levels found by the U.S. Food and Drug Administration (FDA) were within the range the agency would expect to find in lipsticks formulated with permitted color additives and other ingredients prepared under good manufacturing practice (GMP) conditions. This method will be useful for the FDA and industry in helping to ensure the safety of cosmetic products.

  4. Ultrasonic-energy enhance the ionic liquid-based dual microextraction to preconcentrate the lead in ground and stored rain water samples as compared to conventional shaking method.

    Science.gov (United States)

    Nizamani, Sooraj; Kazi, Tasneem G; Afridi, Hassan I

    2018-01-01

    An efficient preconcentration technique based on ultrasonic-assisted ionic liquid-based dual microextraction (UA-ILDµE) method has been developed to preconcentrate the lead (Pb(+2)) in ground and stored rain water. In the current proposed method, Pb(+2) was complexed with a chelating agent (dithizone), whereas an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was used for extraction purpose. The ultrasonic irradiation and electrical shaking system were applied to enhance the dispersion and extraction of Pb(+2) complex in aqueous samples. For second phase, dual microextraction (DµE phase), the enriched Pb(+2) complex in ionic liquid, extracted back into the acidic aqueous solution and finally determined by flame atomic absorption spectrometry. Some major analytical parameters that influenced the extraction efficiency of developed method, such as pH, concentration of ligand, volume of ionic liquid and samples, time of shaking in thermostatic electrical shaker and ultrasonic bath, effect of back extracting HNO3 volume, matrix effect, centrifugation time and rate were optimized. At the sample volume of 25mL, the calculated preconcentration factor was 62.2. The limit of detection of proposed procedure for Pb(+2) ions was found to be 0.54μgL(-1). The validation of developed method was performed by the analysis of certified sample of water SRM 1643e and standard addition method in a real water sample. The extraction recovery of Pb(+2) was enhanced≥2% with shaking time of 80s in ultrasonic bath as compared to used thermostatic electrical shaker, where for optimum recovery up to 10min was required. The developed procedure was successfully used for the enrichment of Pb(+2) in ground and stored rain water (surface water) samples of an endemic region of Pakistan. The resulted data indicated that the ground water samples were highly contaminated with Pb(+2), while some of the surface water samples were also have higher values of Pb(+2) than permissible

  5. A simple method based on ICP-MS for estimation of background levels of arsenic, cadmium, copper, manganese, nickel, lead, and selenium in blood of the Brazilian population.

    Science.gov (United States)

    Nunes, Juliana A; Batista, Bruno L; Rodrigues, Jairo L; Caldas, Naise M; Neto, Jose A G; Barbosa, Fernando

    2010-01-01

    Throughout the world, biomonitoring has become the standard for assessing exposure of individuals to toxic elements as well as for responding to serious environmental public health problems. However, extensive biomonitoring surveys require rapid and simple analytical methods. Thus, a simple and high-throughput method is proposed for the determination of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se) in blood samples by using inductively coupled plasma-mass spectrometry (ICP-MS). Prior to analysis, 200 microl of blood samples was mixed with 500 microl of 10% v/v tetramethylammonium hydroxide (TMAH) solution, incubated for 10 min, and subsequently diluted to 10 ml with a solution containing 0.05% w/v ethylenediamine tetraacetic acid (EDTA) + 0.005% v/v Triton X-100. After that, samples were directly analyzed by ICP-MS (ELAN DRC II). Rhodium was selected as an internal standard with matrix-matching calibration. Method detection limits were 0.08, 0.04, 0.5, 0.09, 0.12, 0.04, and 0.1 microg//L for As, Cd, Cu, Mn, Ni, Pb, and Se, respectively. Validation data are provided based on the analysis of blood samples from the trace elements inter-\\comparison program operated by the Institut National de Sante Publique du Quebec, Canada. Additional validation was provided by the analysis of human blood samples by the proposed method and by using electrothermal atomic absorption spectrometry (ETAAS). The method was subsequently applied for the estimation of background metal blood values in the Brazilian population. In general, the mean concentrations of As, Cd, Cu, Mn, Ni, Pb, and Se in blood were 1.1, 0.4, 890, 9.6, 2.1, 65.4, and 89.3 microg/L, respectively, and are in agreement with other global populations. Influences of age, gender, smoking habits, alcohol consumption, and geographical variation on the values were also considered. Smoking habits influenced the levels of Cd in blood. The levels of Cu, Mn, and Pb were

  6. A new tunable dispersive liquid-liquid micro extraction method developed for the simultaneous preconcentration of lead and cadmium from lakes water: a multivariate study

    Science.gov (United States)

    Bilal, Muhammad; Kazi, Tasneem Gul; Afridi, Hassan Imran; Ali, Jamshed; Baig, Jameel Ahmed; Arain, Mohammad Balal; Khan, Mustafa

    2017-08-01

    A green tunable dispersive liquid-liquid micro extraction (TDLLME) technique was established for the simultaneous enrichment of lead (Pb) and cadmium (Cd) from different lakes water before analysis by flame atomic absorption spectrometry (FAAS). A solvent known as tunable polarity solvent (TPS), mixture of 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) and 1-decanol, has been employed as extractant in aqueous medium. In first step this mixture can be made polar by slowly bubbling the antisolvent trigger (CO2) through the solution, which makes a monophasic solution. During this step hydrophobic complexes of the metals with 8-hydroxy quinoline (8-HQ) were extracted by TPS. Then the mixture was switched back to hydrophobic one by heating and/or bubbling nitrogen, turning the mixture into two phases again. In second phase the metals were leached out from the complexes entrapped in TPS, by treating with a solution of nitric acid and exposing the mixture to CO2, which switched the mixture into single phase. Then N2 purging and/or heating again turned the mixture into two phases. The acidic aqueous phase containing the metals was introduced to FAAS for analysis, whereas TPS was recycled for next experiment. Different parameters, affecting the efficiency the technique, were optimized by multivariate approach. The method was applied to certified reference material of water and to a real sample spiked with standards of known concentration, to confirm its validity and accuracy. LOD obtained for Pb and Cd were 0.560 and 0.056 μg L- 1 respectively. The developed method was applied successfully to the real water samples of two lakes of Sindh, Pakistan.

  7. Identification and Decay Studies of New, Neutron-Rich Isotopes of Bismuth, Lead and Thallium by means of a Pulsed Release Element Selective Method

    CERN Multimedia

    Mills, A; Kugler, E; Van duppen, P L E; Lettry, J

    2002-01-01

    % IS354 \\\\ \\\\ It is proposed to produce, identify and investigate at ISOLDE new, neutron-rich isotopes of bismuth, lead and thallium at the mass numbers A=215 to A=218. A recently tested operation mode of the PS Booster-ISOLDE complex, taking an advantage of the unique pulsed proton beam structure, will be used together with a ThC target in order to increase the selectivity. The decay properties of new nuclides will be studied by means of $\\beta$-, $\\gamma$- and X- ray spectroscopy methods. The expected information on the $\\beta$-half-lives and excited states will be used for testing and developing the nuclear structure models ``south-east'' of $^{208}$Pb, and will provide input data for the description of the r-process path at very heavy nuclei. The proposed study of the yields and the decay properties of those heavy nuclei produced in the spallation of $^{232}$Th by a 1~GeV proton beam contributes also the data necessary for the simulations of a hybrid accelerator-reactor system.

  8. Magneto-optical and Microwave Properties of LuBiIG Thin Films Prepared by Liquid Phase Epitaxy Method from Lead-Free Flux

    Science.gov (United States)

    Yang, Qing-Hui; Zhnag, Huai-Wu; Wen, Qi-Ye; Liu, Ying-Li; Ihor, Syvorotka M.; Ihor, Syvorotka I.

    2009-04-01

    Lu2.1 Bi0.9Fe5 O12 (LuBiIG) garnet films are prepared by liquid phase epitaxy (LPE) method on gadolinium gallium garnet (GGG) substrates from lead-free flux. Three-inch single crystal garnet films with (444) orientation and good surface are successfully fabricated. The lattice mismatch to the GGG(111) substrate is as small as 0.08%. The ferromagnetic resonance (FMR) linewidth of the film is 2ΔH = 2.8-5.1 Oe, the Faraday rotation is 1.64 deg/μm at 633 nm at room temperature and the optical absorption coefficient of the film is 600 cm-1 in visible range and about 100-170 cm-1 when the wavelength is larger than 800 nm. The epitaxy film possesses dominating in-plane magnetization with a saturation magnetization of about 1562G. These superior optical, magnetic-optical (MO) and microwave properties of our garnet films have potential applications in both MO and microwave devices.

  9. Topological and Geometric Tools for the Analysis fo Complex Networks

    Science.gov (United States)

    2013-10-01

    faster than the current subgradient techniques for network optimization. Below, we will highlight some of the major advances. Some highlights are...Maximization Most existing work uses dual decomposition and subgradient methods to solve network optimization problems in a distributed manner, which...neighborhood. Simulation results illustrate the significant multiple order of magnitude performance gains of this method relative to subgradient methods

  10. Superquantile Regression: Theory, Algorithms, and Applications

    Science.gov (United States)

    2014-12-01

    57 1. Dualization of Risk . . . . . . . . . . . . . . . . . . . . . 58 2. Subgradient Method... subgradient , coordinate descent, and cutting plane methods), for increasing sample sizes ν. . . . . . . . . . . . . . . 77 Figure 7. Example A: Primal...79 Table 5. Example A: Solution vectors and computing times (sec.) for solv- ing Dν when implementing the subgradient method

  11. Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods. 2. Original paint layer samples.

    Science.gov (United States)

    Monico, Letizia; Van der Snickt, Geert; Janssens, Koen; De Nolf, Wout; Miliani, Costanza; Dik, Joris; Radepont, Marie; Hendriks, Ella; Geldof, Muriel; Cotte, Marine

    2011-02-15

    The darkening of the original yellow areas painted with the chrome yellow pigment (PbCrO(4), PbCrO(4)·xPbSO(4), or PbCrO(4)·xPbO) is a phenomenon widely observed on several paintings by Vincent van Gogh, such as the famous different versions of Sunflowers. During our previous investigations on artificially aged model samples of lead chromate, we established for the first time that darkening of chrome yellow is caused by reduction of PbCrO(4) to Cr(2)O(3)·2H(2)O (viridian green), likely accompanied by the presence of another Cr(III) compound, such as either Cr(2)(SO(4))(3)·H(2)O or (CH(3)CO(2))(7)Cr(3)(OH)(2) [chromium(III) acetate hydroxide]. In the second part of this work, in order to demonstrate that this reduction phenomenon effectively takes place in real paintings, we study original paint samples from two paintings of V. van Gogh. As with the model samples, in view of the thin superficial alteration layers that are present, high lateral resolution spectroscopic methods that make use of synchrotron radiation (SR), such as microscopic X-ray absorption near edge (μ-XANES) and X-ray fluorescence spectrometry (μ-XRF) were employed. Additionally, μ-Raman and mid-FTIR analyses were carried out to completely characterize the samples. On both paint microsamples, the local presence of reduced Cr was demonstrated by means of μ-XANES point measurements. The presence of Cr(III) was revealed in specific areas, in some cases correlated to the presence of Ba(sulfate) and/or to that of aluminum silicate compounds.

  12. SIGNIFICANCE OF TARGETED EXOME SEQUENCING AND METHODS OF DATA ANALYSIS IN THE DIAGNOSIS OF GENETIC DISORDERS LEADING TO THE DEVELOPMENT OF EPILEPTIC ENCEPHALOPATHY

    Directory of Open Access Journals (Sweden)

    Tatyana Victorovna Kozhanova

    2017-08-01

    Full Text Available Epilepsy is the most common serious neurological disorder, and there is a genetic basis in almost 50% of people with epilepsy. The diagnosis of genetic epilepsies makes to estimate reasons of seizures in the patient. Last decade has shown tremendous growth in gene sequencing technologies, which have made genetic tests available. The aim is to show significance of targeted exome sequencing and methods of data analysis in the diagnosis of hereditary syndromes leading to the development of epileptic encephalopathy. We examined 27 patients with с early EE (resistant to antiepileptic drugs, psychomotor and speech development delay in the psycho-neurological department. Targeted exome sequencing was performed for patients without a previously identified molecular diagnosis using 454 Sequencing GS Junior sequencer (Roche and IlluminaNextSeq 500 platform. As a result of the analysis, specific epilepsy genetic variants were diagnosed in 27 patients. The greatest number of cases was due to mutations in the SCN1A gene (7/27. The structure of mutations for other genes (mutations with a minor allele frequency of less than 0,5% are presented: ALDH7A1 (n=1, CACNA1C (n=1, CDKL5 (n=1, CNTNAP2 (n=2, DLGAP2 (n=2, DOCK7 (n=2, GRIN2B (n=2, HCN1 (n=1, NRXN1 (n=3, PCDH19 (n=1, RNASEH2B (n=2, SLC2A1 (n=1, UBE3A (n=1. The use of the exome sequencing in the genetic practice allows to significantly improve the effectiveness of medical genetic counseling, as it made possible to diagnose certain variants of genetically heterogeneous groups of diseases with similar of clinical manifestations.

  13. Mixed-Integer Nonconvex Quadratic Optimization Relaxations and Performance Analysis

    Science.gov (United States)

    2016-10-11

    column generation, subgradient method, and pattern search. Column generation adds the most beneficial stations sequentially until the plan quality...beneficial. For each update resulted from column generation, the subgradient method improves the selected stations locally by reshaping the apertures and...updating the beam angles toward a descent subgradient direction. The algorithm continues to improve the selected stations locally DISTRIBUTION A

  14. Left ventricular pacing lead insertion via the coronary sinus cardioplegia cannula: a novel method for temporary biventricular pacing during reoperative cardiac surgery.

    Science.gov (United States)

    Wang, Daniel Y; Gerrah, Rabin; Rusanov, Alexander; Yalamanchi, Vinay; Cabreriza, Santos E; Spotnitz, Henry M

    2011-07-01

    Temporary biventricular pacing to treat low output states after cardiac surgery is an active area of investigation. Reoperative cases are not studied due to adhesions, which preclude left ventricular mobilization to place epicardial pacing wires. In such patients, inserting a temporary left ventricular lead via the coronary sinus cardioplegia cannula may allow for biventricular pacing. We developed a novel technique for intraoperative left ventricular lead placement. Eight domestic pigs underwent median sternotomy and pericardiotomy. Temporary pacing wires were sewn to the right atrium and right ventricle. Complete heart block was induced by ethanol ablation of the atrioventricular node. A 13-French retrograde cardioplegia catheter was introduced via the right atrial free wall into the coronary sinus. A 6-French left ventricular pacing lead was inserted into the cardioplegia catheter and advanced into the coronary sinus during biventricular pacing until left ventricular capture was detected by electrocardiogram and arterial pressure monitoring. Left ventricular capture success rate and electrical performance were recorded during five placement attempts. Left ventricular capture was achieved on 80% of insertion attempts. Left ventricular capture without diaphragmatic pacing was achieved in 7 pigs. Lead tip locations were mostly in lateral and posterior basal coronary vein branches. There were no arrhythmias, bleeding, or perforation associated with lead insertion. Intraoperative biventricular pacing with a left ventricular pacing lead inserted via the coronary sinus cardioplegia cannula is feasible, using standard instrumentation and without requiring cardiac manipulation. This approach merits further study in patients undergoing reoperative cardiac surgery. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  15. Analysis of accidents leading to amputations associated with operating with press machines, using Ishikawa and SCAT Combined method in a car manufacturing company

    Directory of Open Access Journals (Sweden)

    J. Nematolahi

    2015-12-01

      Conclusion: According to results, the main interfce causes of accidents leading to amputation due to operating with press machines is hurry at work because of increased production volume particularly by contractor companies. Furthermore, non-dynamic HSE system accompanied by ineffective supervision of personnel’s unsafe acts by the first layers of management are recognized as the basic causes of such accidents.

  16. Randomized gradient-free method for multiagent optimization over time-varying networks.

    Science.gov (United States)

    Yuan, Deming; Ho, Daniel W C

    2015-06-01

    In this brief, we consider the multiagent optimization over a network where multiple agents try to minimize a sum of nonsmooth but Lipschitz continuous functions, subject to a convex state constraint set. The underlying network topology is modeled as time varying. We propose a randomized derivative-free method, where in each update, the random gradient-free oracles are utilized instead of the subgradients (SGs). In contrast to the existing work, we do not require that agents are able to compute the SGs of their objective functions. We establish the convergence of the method to an approximate solution of the multiagent optimization problem within the error level depending on the smoothing parameter and the Lipschitz constant of each agent's objective function. Finally, a numerical example is provided to demonstrate the effectiveness of the method.

  17. A Cutting Plane and Level Stabilization Bundle Method with Inexact Data for Minimizing Nonsmooth Nonconvex Functions

    Directory of Open Access Journals (Sweden)

    Jie Shen

    2014-01-01

    Full Text Available Under the condition that the values of the objective function and its subgradient are computed approximately, we introduce a cutting plane and level bundle method for minimizing nonsmooth nonconvex functions by combining cutting plane method with the ideas of proximity control and level constraint. The proposed algorithm is based on the construction of both a lower and an upper polyhedral approximation model to the objective function and calculates new iteration points by solving a subproblem in which the model is employed not only in the objective function but also in the constraints. Compared with other proximal bundle methods, the new variant updates the lower bound of the optimal value, providing an additional useful stopping test based on the optimality gap. Another merit is that our algorithm makes a distinction between affine pieces that exhibit a convex or a concave behavior relative to the current iterate. Convergence to some kind of stationarity point is proved under some looser conditions.

  18. HAIR LEAD CONCENTRATION IN NAKHLAK LEAD MINERS VERSUS CONTROL GROUP

    Directory of Open Access Journals (Sweden)

    N IZADI

    2002-03-01

    Full Text Available Introduction. Lead poisoning is a major problem in environmental health. Exposure can occur via air, soil, food and water. Occupational exposure is the most common source of lead poisoning in adults. Lead miners are exposed to an additional source of poisoning in long term. Hair analysis may be used to evaluate chronic lead toxicity. This study compare the hair lead concentration in Nakhlak lead miners and Mohammadieh people who live 130 km far from the lead mine. Methods. Hair samples from 24 Nakhlak lead miners and 26 adult men of Mohammadieh village were gathered, washed by detergent and distilled water and dissolved by wet digestion. Lead concentrations of the samples were measured by flame atomic absorption spectroscopy. Results. There was a significant difference between hair lead concentration of Nakhlak lead miners and Mohammadieh people (P < 0.001. The mean of lead concentrations were 52.43±27.7 µg/g (mean ± SD and 17.32±3.43 µg/g hair of the lead mine workers and the Mohammadieh people, respectively. There was also a significant regression between the number of exposure years and the lead concentration of hair in Nakhlak lead miners (P < 0.001, r=0.8. Discussion. Presence of lead compounds in work environment especially in the air may be an important factor for the difference between hair lead concentration of Nakhlak lead miners and Mohammadieh people. However, the hair lead concentration in Mohammadieh people is also reasonably high. It means that these people are also exposed to lead through the other sources e.g. food, soil, water and air.

  19. A new lead for nonpeptidic active-site-directed inhibitors of the severe acute respiratory syndrome coronavirus main protease discovered by a combination of screening and docking methods.

    Science.gov (United States)

    Kaeppler, Ulrich; Stiefl, Nikolaus; Schiller, Markus; Vicik, Radim; Breuning, Alexander; Schmitz, Werner; Rupprecht, Daniel; Schmuck, Carsten; Baumann, Knut; Ziebuhr, John; Schirmeister, Tanja

    2005-11-03

    The coronavirus main protease, M(pro), is considered to be a major target for drugs suitable for combating coronavirus infections including severe acute respiratory syndrome (SARS). An HPLC-based screening of electrophilic compounds that was performed to identify potential M(pro) inhibitors revealed etacrynic acid tert-butylamide (6a) as an effective nonpeptidic inhibitor. Docking studies suggested a binding mode in which the phenyl ring acts as a spacer bridging the inhibitor's activated double bond and its hydrophobic tert-butyl moiety. The latter is supposed to fit into the S4 pocket of the target protease. Furthermore, these studies revealed etacrynic acid amide (6b) as a promising lead for nonpeptidic active-site-directed M(pro) inhibitors. In a fluorimetric enzyme assay using a novel fluorescence resonance energy transfer (FRET) pair labeled substrate, compound 6b showed a K(i) value of 35.3 muM. Since the novel lead compound does not target the S1', S1, and S2 subsites of the enzyme's substrate-binding pockets, there is room for improvement that underlines the lead character of compound 6b.

  20. An Approximate Proximal Bundle Method to Minimize a Class of Maximum Eigenvalue Functions

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available We present an approximate nonsmooth algorithm to solve a minimization problem, in which the objective function is the sum of a maximum eigenvalue function of matrices and a convex function. The essential idea to solve the optimization problem in this paper is similar to the thought of proximal bundle method, but the difference is that we choose approximate subgradient and function value to construct approximate cutting-plane model to solve the above mentioned problem. An important advantage of the approximate cutting-plane model for objective function is that it is more stable than cutting-plane model. In addition, the approximate proximal bundle method algorithm can be given. Furthermore, the sequences generated by the algorithm converge to the optimal solution of the original problem.

  1. A Block Coordinate Descent Method for Multi-Convex Optimization with Applications to Nonnegative Tensor Factorization and Completion

    Science.gov (United States)

    2012-08-01

    inequality for nonsmooth subanalytic functions with applications to subgradient dynamical systems, SIAM Journal on Optimization, 17 (2007), pp. 1205...1223. [14] J. Bolte, A. Daniilidis, A. Lewis, and M. Shiota, Clarke subgradients of stratifiable functions, SIAM Journal on Optimization, 18 (2007

  2. Nonsmooth optimization approaches to VDA of models with on/off parameterizations: Theoretical issues

    Science.gov (United States)

    Zhu, J.; Kamachi, M.; Zhou, G. Q.

    2002-05-01

    Some variational data assimilation problems of time- and space-discrete models with on/off parameterizations; can be regarded as nonsmooth optimization problems. Some theoretical issues related to those problems is systematically addressed, One of the basic concept in nonsmooth optimization is subgradient, a generalized notation of a gradient of the cost function. First it is shown that the concept of subgradient leads to a clear definition of the adjoint variables in the conventional adjoint model at singular points caused by on/off switches, Using an illustrated example of a multi-layer diffusion model with the convective adjustment, it is proved that the solution of the conventional adjoint model can not be interpreted as Gateaux derivatives or directional derivatives, at singular points, but can be interpreted as a subgradient of the cost function. Two existing smooth optimization approaches are then reviewed which are used in current data assimilation practice, The first approach is the conventional adjoint model plus smooth optimization algorithms. Some conditions under which the approach can converge to the minimal are discussed, Another approach is smoothing and regularization approach, which removes some thresholds in physical parameterizations. Two nonsmooth optimization approaches are also reviewed, One is the subgradient method, which uses the conventional adjoint model. The method is convergent, but very slow. Another approach, the bundle methods are more efficient. The main idea of the bundle method is to use the minimal norm vector of subdifferential, which is the convex hull of all subgradients, as the descent director. However finding all subgradients is very difficult in general, Therefore bundle methods are modified to use only one subgradient that can be calculated by the conventional adjoint model. In order to develop an efficient bundle method, a set-valued adjoint model, as a generalization of the conventional adjoint model, is proposed, It

  3. Identifying quantitative operation principles in metabolic pathways: a systematic method for searching feasible enzyme activity patterns leading to cellular adaptive responses

    Directory of Open Access Journals (Sweden)

    Sorribas Albert

    2009-11-01

    Full Text Available Abstract Background Optimization methods allow designing changes in a system so that specific goals are attained. These techniques are fundamental for metabolic engineering. However, they are not directly applicable for investigating the evolution of metabolic adaptation to environmental changes. Although biological systems have evolved by natural selection and result in well-adapted systems, we can hardly expect that actual metabolic processes are at the theoretical optimum that could result from an optimization analysis. More likely, natural systems are to be found in a feasible region compatible with global physiological requirements. Results We first present a new method for globally optimizing nonlinear models of metabolic pathways that are based on the Generalized Mass Action (GMA representation. The optimization task is posed as a nonconvex nonlinear programming (NLP problem that is solved by an outer-approximation algorithm. This method relies on solving iteratively reduced NLP slave subproblems and mixed-integer linear programming (MILP master problems that provide valid upper and lower bounds, respectively, on the global solution to the original NLP. The capabilities of this method are illustrated through its application to the anaerobic fermentation pathway in Saccharomyces cerevisiae. We next introduce a method to identify the feasibility parametric regions that allow a system to meet a set of physiological constraints that can be represented in mathematical terms through algebraic equations. This technique is based on applying the outer-approximation based algorithm iteratively over a reduced search space in order to identify regions that contain feasible solutions to the problem and discard others in which no feasible solution exists. As an example, we characterize the feasible enzyme activity changes that are compatible with an appropriate adaptive response of yeast Saccharomyces cerevisiae to heat shock Conclusion Our results

  4. The Method of Loci as a Mnemonic Device to Facilitate Learning in Endocrinology Leads to Improvement in Student Performance as Measured by Assessments

    Science.gov (United States)

    Qureshi, Ayisha; Rizvi, Farwa; Syed, Anjum; Shahid, Aqueel; Manzoor, Hana

    2014-01-01

    Cognitive psychology has demonstrated that the way knowledge is structured in memory determines the ability to retain, recall, and use it to solve problems. The method of loci (MOL) is a mnemonic device that relies on spatial relationships between "loci" (e.g., locations on a familiar route or rooms in a familiar building) to arrange and…

  5. Determination of cadmium and lead in mussels by electrothermal atomic absorption spectrometry using an ultrasound-assisted extraction method optimized by factorial design

    Energy Technology Data Exchange (ETDEWEB)

    Lavilla, I.; Capelo, J.L.; Bendicho, C. [Departamento de Quimica Analitica y Alimentaria, Universidad de Vigo, Facultad de Ciencias (Quimicas), As Lagoas - Marcosende s/n. E-36200 Vigo (Spain)

    1999-02-01

    A simple and rapid method is described for the quantitative extraction and determination of Cd and Pb in mussel tissue (Mytilus edulis). The method is based on the quantitative ultrasound-assisted extraction (i.e. sample mass at mg level) of the two metals using diluted nitric acid as extractant. The extraction procedure is carried out in autosampler cups of the graphite furnace (typically, less than 20 mg). A two-level full factorial design (2{sup 4}) was applied to optimize the variables influencing the ultrasound extraction process. These variables were: extraction time, ultrasound amplitude, nitric acid concentration and particle size. Optimization results showed that acid concentration and particle size were the more significant variables. Determination of Cd and Pb in extracts obtained after ultrasound treatment was carried out by Electrothermal Atomic Absorption Spectrometry. The method was validated by statistically comparing the metal contents found with the certified ones corresponding to the BCR 278 mussel tissue. No significant differences were observed for P= 0.05. LODs for Cd and Pb in mussel tissue were 0.019 and 0.37 {mu}g g{sup -1}. RSDs values (corresponding to between-batch precision for n= 5) were 2.2 and 6.7% for Cd and Pb, respectively. The method was applied to measure the contents of Cd and Pb in mussels used as pollution bioindicators from the Galician coast (Ria de Vigo, Spain). (orig.) With 2 figs., 9 tabs., 6 refs.

  6. ECG monitoring leads and special leads.

    Science.gov (United States)

    Francis, Johnson

    ECG monitoring is common place in the hospital and even pre-hospital setting. The need for different types of lead systems in different settings has been emphasised. Simple three electrode bipolar recording is ubiquitous for monitoring. This can be used to record modified bipolar chest leads as well. Using five leads gives the option of getting a chest lead in addition to bipolar limb leads, enhancing detection of ischemia during procedures. Lead stability is important when the movement of the subject is maximum as in exercise testing. Mason-Likar modification with limb leads shifted to the torso is popular for exercise testing, though the diagnostic value of the ECG is altered. Lund system with leads on proximal part of limbs have both stability and fair diagnostic value. EASI lead system permits derivation of 12 leads from just five electrodes. Lewis lead and the newly devised modified limb lead system are useful in enhancing detection of atrial activity. Fontaine lead has been designed to improve visualization of Epsilon wave in arrhythmogenic right ventricular dysplasia. Copyright © 2016 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

  7. Effect of deposition temperature on the structural, morphological and optical band gap of lead selenide thin films synthesized by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Hone, Fekadu Gashaw, E-mail: fekeye@gmail.com [Hawassa University, Department of Physics, Hawassa (Ethiopia); Ampong, Francis Kofi [Kwame Nkrumah University of Science and Technology, Department of Physics, Kumasi (Ghana)

    2016-11-01

    Lead selenide (PbSe) nanocrystalline thin films have been deposited on silica glass substrates by the chemical bath deposition technique. The samples were deposited at the bath temperatures of 60, 75 and 90 °C respectively and characterized by a variety of techniques. The XRD results revealed that the PbSe thin film deposited at 60 °C was amorphous in nature. Films deposited at higher temperatures exhibited sharp and intense diffraction peaks, indicating an improvement in crystallinety. The deposition temperature also had a strong influence on the preferred orientation of the crystallites as well as other structural parameters such as microstrain and dislocation density. From the SEM study it was observed that film deposited at 90 °C had well defined crystallites, uniformly distributed over the entire surface of the substrate. The EDAX study confirmed that the samples deposited at the higher temperature had a better stoichiometric ratio. The optical band gap varied from 2.26 eV to 1.13 eV with increasing deposition temperature. - Highlights: • The crystallinety of the films improved as the deposition temperature increased. • The deposition temperature strongly influenced the preferred orientations. • Microstrain and dislocation density are decreased linearly with deposition temperature. • Band gap decreased from 2.26 eV to 1.13 eV as the deposition temperature increased.

  8. Validation of a method to quantify chromium, cadmium, manganese, nickel and lead in human whole blood, urine, saliva and hair samples by electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Olmedo, P.; Pla, A.; Hernandez, A.F.; Lopez-Guarnido, O.; Rodrigo, L. [Department of Legal Medicine and Toxicology, University of Granada, School of Medicine (Spain); Gil, F., E-mail: fgil@ugr.es [Department of Legal Medicine and Toxicology, University of Granada, School of Medicine (Spain)

    2010-02-05

    For biological monitoring of heavy metal exposure in occupational toxicology, usually whole blood and urine samples are the most widely used and accepted matrix to assess internal xenobiotic exposure. Hair samples and saliva are also of interest in occupational and environmental health surveys but procedures for the determination of metals in saliva and hair are very scarce and to our knowledge there is no validation of a method to quantify Cr, Cd, Mn, Ni and Pb in four different human biological materials (whole blood, urine, saliva and axilary hair) by electrothermal atomization atomic absorption spectrometry (ETAAS). In the present study, quantification methods for the determination of Cr, Cd, Mn, Ni and Pb in whole blood, urine, saliva and axilary hair were validated according to the EU common standards. Pyrolisis and atomization temperatures have been determined. The main parameters evaluated were: detection and quantification limits, linearity range, repeatability, reproducibility, recovery and uncertainty. Accuracy of the methods was tested with the whole blood, urine and hair certified reference materials and recoveries of the spiked samples were acceptable ranged from 96.3 to 107.8%.

  9. Learn about Lead

    Science.gov (United States)

    ... Protection Agency Search Search Lead Contact Us Share Learn about Lead General Lead Information Read more about ... water, soil, consumer products, food, and occupational settings. Learn more about sources of lead exposure: At home ...

  10. Lead Poisoning Prevention Tips

    Science.gov (United States)

    ... or removed safely. How are children exposed to lead? Lead-based paint and lead contaminated dust are ... What can be done to prevent exposure to lead? It is important to determine the construction year ...

  11. Lead levels - blood

    Science.gov (United States)

    Blood lead levels ... is used to screen people at risk for lead poisoning. This may include industrial workers and children ... also used to measure how well treatment for lead poisoning is working. Lead is common in the ...

  12. Derivative spectrophotometric determination of trace lead in alloys and biological samples after separation and preconcentration with the ion pair of 2-(5-bromo-2-pyridylazo-5-diethylaminophenol and ammonium tetraphenylborate on microcrystalline naphthalene or by column method

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Taher

    2003-12-01

    Full Text Available Lead is quantitatively retained on 2-(5-bromo-2-pyridylazo-5-diethylaminophenol-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 4.0–6.0 from a large volume of aqueous solutions of various samples. After filtration, the solid mass consisting of the lead complex and naphthalene was dissolved with 5 mL of dimethylformamide and the metal was determined by third derivative spectrophotometry. Lead complex can alternatively be quantitatively adsorbed on ammonium tetraphenylborate-naphthalene adsorbent packed in a column and determined similarly. About 0.2 μg of lead can be concentrated in a column from 300 mL of aqueous sample, where its concentration is as low as 0.7 ng/mL. The interference of a large number of anions and cations has been studied and the optimized conditions developed have been utilized for the trace determination of lead in various samples.

  13. Autoinflation Leading to Failure of Two-Piece Ambicor Implantable Penile Prosthesis: An Outcome from a Methodical Treatment of Recalcitrant Stuttering Priapism

    Directory of Open Access Journals (Sweden)

    R. Charles Welliver

    2014-01-01

    Full Text Available Introduction. We present the case of a patient who received a two-piece Ambicor penile prosthesis for idiopathic recurrent “stuttering” priapism refractory to other treatment options. The patient returned unable to deflate the device due to an interesting anatomically induced mechanical failure. Aims. To describe the method and findings of this inflatable prosthesis failure. Results. Prosthesis failure occurred due to restrictive corporal diameter and the unique characteristics of fluid reservoir location in the two-piece inflatable prosthesis. The patient was successfully converted to a semirigid prosthesis with resolution of the pain that was due to his prosthesis autoinflation. Conclusion. Stuttering priapism remains a challenging clinical problem. Penile implantation is a reasonable long-term solution in a patient refractory to less invasive options. In patients with fibrotic corpora, a malleable device should be considered (at least temporarily if unable to dilate comfortably to 13 mm.

  14. CRITICAL ASSESSMENT OF CONTRIBUTION FROM INDIAN PUBLICATIONS: THE ROLE OF IN SILICO DESIGNING METHODS LEADING TO DRUGS OR DRUG-LIKE COMPOUNDS USING TEXT BASED MINING AND ASSOCIATION

    Directory of Open Access Journals (Sweden)

    Pawan Kumar

    2017-09-01

    Full Text Available Over the several decades, India is constantly challenged by communicable and non-communicable diseases which are originated either by poor lifestyle or by environmental factors. The pools of diseases are constantly posing serious threats to mankind especially among the poverty-stricken families. Scientific communities across the globe are working continuously to design drug molecules to overcome the burden of these life threaten diseases. In last three decades, many computational algorithms and tools have been developed to identify potential drug targets and their inhibitors. It is believed that computational techniques have reduced the time and money required to develop an inhibitor into drug. However, applicability and deliverability of these in silico techniques in rational drug designing are not fully evaluated. In the present study, PubMed/Medline extracted data driven analysis has been performed to highlight the influence and progress of the theoretical methods in the field of drug discovery across India and compared with the world. Drug discovery related keyword dictionary has been built and utilized to select only drug discovery related PubMed abstract. A second keyword set (related to bioinformatics tools is used for normalized pointwise mutual information (PMI based association analysis. Observations show that drug discovery has been an interdisciplinary research and used many tools starting with QSAR, docking, pharmacophore, Molecular Simulations etc. The publications contributed from India (2% are similar as compared to the contribution in total world publications, suggesting large scope in future. Data coverage as represented since 1990-2015 in PubMed as indicated by number of publications associated with drug discovery is almost same in world and India (~75%. Emerging institutes/Universities are contributing since last 10 years as observed from Indian publication list. However, this method has many limitations as discussed.

  15. HAMS: High-Affinity Mass Spectrometry Screening. A High-Throughput Screening Method for Identifying the Tightest-Binding Lead Compounds for Target Proteins with No False Positive Identifications

    Science.gov (United States)

    Imaduwage, Kasun P.; Go, Eden P.; Zhu, Zhikai; Desaire, Heather

    2016-11-01

    A major challenge in drug discovery is the identification of high affinity lead compounds that bind a particular target protein; these leads are typically identified by high throughput screens. Mass spectrometry has become a detection method of choice in drug screening assays because the target and the ligand need not be modified. Label-free assays are advantageous because they can be developed more rapidly than assays requiring labels, and they eliminate the risk of the label interfering with the binding event. However, in commonly used MS-based screening methods, detection of false positives is a major challenge. Here, we describe a detection strategy designed to eliminate false positives. In this approach, the protein and the ligands are incubated together, and the non-binders are separated for detection. Hits (protein binders) are not detectable by MS after incubation with the protein, but readily identifiable by MS when the target protein is not present in the incubation media. The assay was demonstrated using three different proteins and hundreds of non-inhibitors; no false positive hits were identified in any experiment. The assay can be tuned to select for ligands of a particular binding affinity by varying the quantity of protein used and the immobilization method. As examples, the method selectively detected inhibitors that have Ki values of 0.2 μM, 50 pM, and 700 pM. These findings demonstrate that the approach described here compares favorably with traditional MS-based screening methods.

  16. Thirty-day mortality leads to underestimation of postoperative death after liver resection: A novel method to define the acute postoperative period.

    Science.gov (United States)

    Schiergens, Tobias S; Dörsch, Maximilian; Mittermeier, Laura; Brand, Katharina; Küchenhoff, Helmut; Lee, Serene M L; Feng, Hao; Jauch, Karl-Walter; Werner, Jens; Thasler, Wolfgang E

    2015-12-01

    Postoperative mortality commonly is defined as death occurring within 30 days of surgery or during hospitalization. After resection for liver malignancies, this definition may result in underreporting, because mortality caused by postoperative complications can be delayed as the result of improved critical care. The aim of this study was to estimate statistically the acute postoperative period (APP) after partial hepatectomy and to compare mortality within this phase to standard timestamps. From a prospective database, 784 patients undergoing resection for primary and secondary hepatic malignancies between 2003 and 2013 were reviewed. For estimation of APP, a novel statistical method applying tests for a constant postoperative hazard was implemented. Multivariable mortality analysis was performed. The APP was determined to last for 80 postoperative days (95% confidence interval 40-100 days). Within this period, 55 patients died (7.0%; 80-day mortality). In comparison, 30-day mortality (N = 32, 4.0%) and in-hospital death (N = 39, 5.0%) were relevantly less. No patient died between postoperative days 80 and 90. The causes of mortality within 30 days and from days 30-80 did not greatly differ, especially regarding posthepatectomy liver failure (44% vs 39%, P = .787). Septic complications, however, tended to cause late deaths more frequently (43% vs 25%, P = .255). Comorbidities (Charlson comorbidity index ≥ 3; P = .046), increased preoperative alanine aminotransferase activity (P = .030), and major liver resection (P = .035) were independent risk factors of 80-day mortality. After liver resection for primary and secondary malignancies, 90-day rather than 30-day or in-hospital mortality should be used to avoid underreporting of deaths. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Lead and the Romans

    Science.gov (United States)

    Reddy, Aravind; Braun, Charles L.

    2010-01-01

    Lead poisoning has been a problem since early history and continues into modern times. An appealing characteristic of lead is that many lead salts are sweet. In the absence of cane and beet sugars, early Romans used "sugar of lead" (lead acetate) to sweeten desserts, fruits, and sour wine. People most at risk would have been those who…

  18. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... Environmental Protection Agency Search Search Lead (Pb) Air Pollution Contact Us Share As a result of EPA's ... protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Basic Information How does lead get in the ...

  19. Working towards accreditation by the International Standards Organization 15189 Standard: how to validate an in-house developed method an example of lead determination in whole blood by electrothermal atomic absorption spectrometry.

    Science.gov (United States)

    Garcia Hejl, Carine; Ramirez, Jose Manuel; Vest, Philippe; Chianea, Denis; Renard, Christophe

    2014-09-01

    Laboratories working towards accreditation by the International Standards Organization (ISO) 15189 standard are required to demonstrate the validity of their analytical methods. The different guidelines set by various accreditation organizations make it difficult to provide objective evidence that an in-house method is fit for the intended purpose. Besides, the required performance characteristics tests and acceptance criteria are not always detailed. The laboratory must choose the most suitable validation protocol and set the acceptance criteria. Therefore, we propose a validation protocol to evaluate the performance of an in-house method. As an example, we validated the process for the detection and quantification of lead in whole blood by electrothermal absorption spectrometry. The fundamental parameters tested were, selectivity, calibration model, precision, accuracy (and uncertainty of measurement), contamination, stability of the sample, reference interval, and analytical interference. We have developed a protocol that has been applied successfully to quantify lead in whole blood by electrothermal atomic absorption spectrometry (ETAAS). In particular, our method is selective, linear, accurate, and precise, making it suitable for use in routine diagnostics.

  20. Determining lead sources in Mexico using the lead isotope ratio

    Directory of Open Access Journals (Sweden)

    Chaudhary-Webb Madhu

    2003-01-01

    Full Text Available OBJECTIVE: Lead poisoning can, in some cases, be traced to a specific route or source of exposure on the basis of the individual's blood lead isotope ratio. To assess the major source of lead exposure among women residing in Mexico City, we compared blood, ceramic, and gasoline lead isotope ratios. MATERIAL AND METHODS: The study population, randomly selected from participants of a large trial, (1/1996-12/1996 comprised of 16 women whose lead levels exceeded 10 µg/dl and who reported using lead-glazed ceramics. Lead isotope ratios were performed on a Perkin Elmer 5000 Inductively Coupled Plasma Mass Spectrometer (ICP-MS interfaced with a Perkin Elmer HGA-600MS Electrothermal Vaporization System (ETV. RESULTS: The isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb of both the blood specimens and their corresponding ceramic specimens were highly correlated, with r=0.9979, r²=0.9958, r=0.9957, r²=0.9915 and r=0.9945, r²=0.9890 values for the three isotope ratios, respectively, suggesting that the lead exposure most likely resulted from the use of these ceramic. Measurements of lead isotope ratios from leaded gasoline in use at the time of blood sampling, differed from those in blood and ceramics. CONCLUSIONS: Determining lead isotope ratios can be an efficient tool to identify a major source of lead exposure and to support the implementation of public health prevention and control measures.

  1. Cryogenic current leads

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, F.

    1982-01-01

    Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

  2. Method

    Directory of Open Access Journals (Sweden)

    Ling Fiona W.M.

    2017-01-01

    Full Text Available Rapid prototyping of microchannel gain lots of attention from researchers along with the rapid development of microfluidic technology. The conventional methods carried few disadvantages such as high cost, time consuming, required high operating pressure and temperature and involve expertise in operating the equipment. In this work, new method adapting xurography method is introduced to replace the conventional method of fabrication of microchannels. The novelty in this study is replacing the adhesion film with clear plastic film which was used to cut the design of the microchannel as the material is more suitable for fabricating more complex microchannel design. The microchannel was then mold using polymethyldisiloxane (PDMS and bonded with a clean glass to produce a close microchannel. The microchannel produced had a clean edge indicating good master mold was produced using the cutting plotter and the bonding between the PDMS and glass was good where no leakage was observed. The materials used in this method is cheap and the total time consumed is less than 5 hours where this method is suitable for rapid prototyping of microchannel.

  3. method

    Directory of Open Access Journals (Sweden)

    L. M. Kimball

    2002-01-01

    Full Text Available This paper presents an interior point algorithm to solve the multiperiod hydrothermal economic dispatch (HTED. The multiperiod HTED is a large scale nonlinear programming problem. Various optimization methods have been applied to the multiperiod HTED, but most neglect important network characteristics or require decomposition into thermal and hydro subproblems. The algorithm described here exploits the special bordered block diagonal structure and sparsity of the Newton system for the first order necessary conditions to result in a fast efficient algorithm that can account for all network aspects. Applying this new algorithm challenges a conventional method for the use of available hydro resources known as the peak shaving heuristic.

  4. Leading change: a concept analysis.

    Science.gov (United States)

    Nelson-Brantley, Heather V; Ford, Debra J

    2017-04-01

    To report an analysis of the concept of leading change. Nurses have been called to lead change to advance the health of individuals, populations, and systems. Conceptual clarity about leading change in the context of nursing and healthcare systems provides an empirical direction for future research and theory development that can advance the science of leadership studies in nursing. Concept analysis. CINAHL, PubMed, PsycINFO, Psychology and Behavioral Sciences Collection, Health Business Elite and Business Source Premier databases were searched using the terms: leading change, transformation, reform, leadership and change. Literature published in English from 2001 - 2015 in the fields of nursing, medicine, organizational studies, business, education, psychology or sociology were included. Walker and Avant's method was used to identify descriptions, antecedents, consequences and empirical referents of the concept. Model, related and contrary cases were developed. Five defining attributes of leading change were identified: (a) individual and collective leadership; (b) operational support; (c) fostering relationships; (d) organizational learning; and (e) balance. Antecedents were external or internal driving forces and organizational readiness. The consequences of leading change included improved organizational performance and outcomes and new organizational culture and values. A theoretical definition and conceptual model of leading change were developed. Future studies that use and test the model may contribute to the refinement of a middle-range theory to advance nursing leadership research and education. From this, empirically derived interventions that prepare and enable nurses to lead change to advance health may be realized. © 2016 John Wiley & Sons Ltd.

  5. Blood lead levels and cumulative blood lead index (CBLI) as predictors of late neurodevelopment in lead poisoned children

    Science.gov (United States)

    Nie, Linda H.; Wright, Robert O.; Bellinger, David C.; Hussain, Javed; Amarasiriwardena, Chitra; Chettle, David R.; Pejović-Milić, Ana; woolf, Alan; Shannon, Michael

    2011-01-01

    Objective To find the best lead exposure assessment marker for children. Methods We recruited 11 children, calculated a cumulative blood lead index (CBLI) for the children, measured their concurrent BLL, assessed their development, and measured their bone lead level. Results Nine of 11 children had clinically significant neurodevelopment problems. CBLI and current blood lead level, but not the peak lead level, were significantly or marginally negatively associated with the full-scale IQ score. Conclusion Lead exposure at younger age significantly impacts a child’s later neurodevelopment. CBLI may be a better predictor of neurodevelopment than are current or peak blood lead levels. PMID:21827276

  6. Lead content of foodstuffs.

    Science.gov (United States)

    Mitchell, D G; Aldous, K M

    1974-05-01

    The lead content of a number of foodstuffs, particularly baby fruit juices and milk, is reported. Samples were analyzed in quadruplicate by using an automated Delves cup atomic absorption procedure. A large proportion of the products examined contained significant amounts of lead. Of 256 metal can examined, the contents of 62% contained a lead level of 100 mug/l. or more, 37% contained 200 mug/l. or more and 12% contained 400 mug/l. lead or more. Of products in glass and aluminum containers, only 1% had lead levels in excess of 200 mug/l. Lead levels of contents also correlate with the seam length/volume ratio of the leaded seam can. A survey of bulk milk showed a mean lead level of 40 mug/l. for 270 samples; for canned evaporated milk the mean level was 202 mug/l. These data indicate a potential health hazard.

  7. Lead and tap water

    Science.gov (United States)

    Water contaminated with lead ... The Environmental Protection Agency (EPA) monitors drinking water in the United States. It requires water suppliers to produce annual water quality reports. These reports include information about lead amounts, and they ...

  8. [Study on the method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES)].

    Science.gov (United States)

    Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin

    2015-02-01

    The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was

  9. NA49: lead-lead collision

    CERN Multimedia

    1996-01-01

    This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.

  10. Lead Poisoning (For Parents)

    Science.gov (United States)

    ... Needs a Kidney Transplant Vision Facts and Myths Lead Poisoning KidsHealth > For Parents > Lead Poisoning Print A ... Family en español La intoxicación por plomo About Lead Poisoning If you have young kids, it's important ...

  11. Lead Poisoning in Childhood.

    Science.gov (United States)

    Pueschel, Siegfried M., Ed.; Linakis, James G., Ed.; Anderson, Angela C., Ed.

    The magnitude of childhood lead poisoning has been inexplicably neglected by modern medicine and by legislators. However, since the 1970s, increased attention has been focused on lead poisoning, and advances have been made in several areas, including understanding of the neurodevelopmental and behavioral ramifications of lead poisoning, and…

  12. Lead poisoning: An overview

    Science.gov (United States)

    Gendel, Neil

    1993-01-01

    A problem that should be of great concern to all of us is the lead poisoning of children. First, I would like to present a short overview concerning the reasons everyone should care about lead poisoning, then discuss the history of lead poisoning, what is happening today across the country, and the future.

  13. Lead Poisoning in Children.

    Science.gov (United States)

    Drummond, A. H., Jr.

    1981-01-01

    Early symptoms of lead poisoning in children are often overlooked. Lead poisoning has its greatest effects on the brain and nervous system. The obvious long-term solution to the lead poisoning problem is removal of harmful forms of the metal from the environment. (JN)

  14. Lead encephalopathy in adults

    Directory of Open Access Journals (Sweden)

    Janapareddy Vijaya Bhaskara Rao

    2014-01-01

    Full Text Available Lead poisoning is a common occupational health hazard in developing countries. We report the varied clinical presentation, diagnostic and management issues in two adult patients with lead encephalopathy. Both patients worked in a battery manufacturing unit. Both patients presented with seizures and one patient also complained of abdominal colic and vomiting. Both were anemic and a lead line was present. Blood lead level in both the patients was greater than 25 µg/dl. Magnetic resonance imaging of brain revealed bilateral symmetric involvement of the thalamus, lentiform nucleus in both patients and also the external capsules, sub-cortical white matter in one patient. All these changes, seen as hyperintensities in T2-weighted images suggested demyelination. They were advised avoidance of further exposure to lead and were treated with anti-epileptics; one patient also received D-penicillamine. They improved well on follow-up. Lead encephalopathy is an uncommon but important manifestation of lead toxicity in adults.

  15. Lead in the environment

    Science.gov (United States)

    Pattee, Oliver H.; Pain, Deborah J.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

    2003-01-01

    Anthropogenic uses of lead have probably altered its availability and environmental distribution more than any other toxic element. Consequently, lead concentrations in many living organisms may be approaching thresholds of toxicity for the adverse effects of lead. Such thresholds are difficult to define, as they vary with the chemical and physical form of lead, exposure regime, other elements present and also vary both within and between species. The technological capability to accurately quantify low lead concentrations has increased over the last decade, and physiological and behavioral effects have been measured in wildlife with tissue lead concentrations below those previously considered safe for humans.s.236 Consequently. lead criteria for the protection of wildlife and human health are frequently under review, and 'thresholds' of lead toxicity are being reconsidered. Proposed lead criteria for the protection of natural resources have been reviewed by Eisler. Uptake of lead by plants is limited by its generally low availability in soils and sediments, and toxicity may be limited by storage mechanisms and its apparently limited translocation within most plants. Lead does not generally accumulate within the foliar parts of plants, which limits its transfer to higher trophic levels. Although lead may concentrate in plant and animal tissues, no evidence of biomagnification exists. Acid deposition onto surface waters and soils with low buffering capacity may influence the availability of lead for uptake by plants and animals, and this may merit investigation at susceptible sites. The biological significance of chronic low-level lead exposure to wildlife is sometimes difficult to quantify. Animals living in urban environments or near point sources of lead emission are inevitably subject to greater exposure to lead and enhanced risk of lead poisoning. Increasingly strict controls on lead emissions in many countries have reduced exposure to lead from some sources

  16. ALICE: Simulated lead-lead collision

    CERN Document Server

    2003-01-01

    This track is an example of simulated data modelled for the ALICE detector on the Large Hadron Collider (LHC) at CERN, which will begin taking data in 2008. ALICE will focus on the study of collisions between nuclei of lead, a heavy element that produces many different particles when collided. It is hoped that these collisions will produce a new state of matter known as the quark-gluon plasma, which existed billionths of a second after the Big Bang.

  17. Optimisation of a headspace-solid-phase micro-extraction method for simultaneous determination of organometallic compounds of mercury, lead and tin in water by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Beceiro-González, E; Guimaraes, A; Alpendurada, M F

    2009-07-17

    In this work, a headspace-solid-phase micro-extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) method for multielemental speciation of organometallic compounds of mercury, lead and tin in water samples was upgraded by the introduction of tandem mass spectrometry (MS/MS) as detection technique. The analytical method is based on the ethylation with NaBEt(4) and simultaneous headspace-solid-phase micro-extraction of the derivative compounds followed by GC-MS/MS analysis. The main experimental parameters influencing the extraction efficiency such as derivatisation time, extraction time and extraction temperature were optimized. The overall optimum extraction conditions were the following: a 50 microm/30 microm divinyl-benzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibre, 150 min derivatisation time, 15 min extraction time, sample agitation at 250 rpm and 40 degrees C extraction temperature. The analytical characteristics of the HS-SPME method combined with GC-MS and GC-MS/MS were evaluated. The combination of both techniques HS-SPME and GC-MS/MS allowed to attain lower limits of detection (4-33 ng l(-1)) than those obtained by HS-SPME-GC-MS (17-45 ng l(-1)). The proposed method presented good linear regression coefficients (r(2)>0.9970) and repeatability (4.8-21.0%) for all the compounds under study. The accuracy of the method measured as the average percentage recovery of the compounds in spiked river water and seawater samples was higher than 80% for all the compounds studied, except for monobutyltin in the river water sample. A study of the uncertainty associated with the analytical results was also carried out.

  18. Method

    Directory of Open Access Journals (Sweden)

    Andrey Gnatov

    2015-01-01

    Full Text Available Recently repair and recovery vehicle body operations become more and more popular. A special place here is taken by equipment that provides performance of given repair operations. The most interesting things are methods for recovery of car body panels that allow the straightening without disassembling of car body panels and damaging of existing protective coating. Now, there are several technologies for repair and recovery of car body panels without their disassembly and dismantling. The most perspective is magnetic-pulse technology of external noncontact straightening. Basics of magnetic-pulse attraction, both ferromagnetic and nonferromagnetic thin-walled sheet metal, are explored. Inductor system calculation models of magnetic-pulse straightening tools are presented. Final analytical expressions for excited efforts calculation in the tools under consideration are introduced. According to the obtained analytical expressions, numerical evaluations of excited forces were executed. The volumetric epures of the attractive force radial distributions for different types of inductors were built. The practical testing of magnetic-pulse straightening with research tools is given. Using the results of the calculations we can create effective tools for an external magnetic-pulse straightening of car body panels.

  19. Organic Lead Toxicology

    Directory of Open Access Journals (Sweden)

    Jiří Patočka

    2008-01-01

    Full Text Available Lead is one of the oldest known and most widely studied occupational and environmental poison. Despite intensive study, there is still debate about the toxic effects of lead, both from low-level exposure in the general population owing to environmental pollution and historic use of lead in paint and plumbing and from exposure in the occupational setting. Significant position have organic lead compounds used more than 60 years as antiknock additives in gasoline. Chemical and toxicological characteristics of main tetraalkyl leads used as gasoline additives are discussed in this article. The majority of industries historically associated with high lead exposure have made dramatic advances in their control of occupational exposure. However, cases of unacceptably high exposure and even of frank lead poisoning are still seen, predominantly in the demolition and tank cleaning industries. Nevertheless, in most industries blood lead levels have declined below levels at which signs or symptoms are seen and the current focus of attention is on the subclinical effects of exposure. The significance of some of these effects for the overt health of the workers is often the subject of debate. Inevitably there is pressure to reduce lead exposure in the general population and in working environments, because current studies show that no level of lead exposure appears to be a ‘safe’ and even the current ‘low’ levels of exposure, especially in children, are associated with neurodevelopmental deficits.

  20. Lead-Free Piezoelectrics

    CERN Document Server

    Nahm, Sahn

    2012-01-01

    Ecological restrictions in many parts of the world are demanding the elimination of Pb from all consumer items. At this moment in the piezoelectric ceramics industry, there is no issue of more importance than the transition to lead-free materials. The goal of Lead-Free Piezoelectrics is to provide a comprehensive overview of the fundamentals and developments in the field of lead-free materials and products to leading researchers in the world. The text presents chapters on demonstrated applications of the lead-free materials, which will allow readers to conceptualize the present possibilities and will be useful for both students and professionals conducting research on ferroelectrics, piezoelectrics, smart materials, lead-free materials, and a variety of applications including sensors, actuators, ultrasonic transducers and energy harvesters.

  1. Lead and the skin

    Energy Technology Data Exchange (ETDEWEB)

    Allen, B.R.; Moore, M.R.; Hunter, J.A.A.

    1975-01-01

    The increasing use of lead will continue to give rise to problems of toxicity. Protective measures have resulted in florid lead poisoning becoming rare. Attention has recently turned to the possibility of prolonged exposure to low doses of lead causing morbidity in the absence of the classical clinical features of poisoning. Lead is absorbed mostly through the lungs and gastrointestinal tract. Some is also absorbed through the skin but with inorganic compounds the amount is small. Shortly after the most widely used compound, tetraethyl lead, was first manufactured, cases of toxicity began to occur. Manufacture was forbidden until plant design produced greater safety. Significant absorption can occur through the skin. The hazard to those handling leaded gasoline in a normal manner is probably small, mainly because 95 percent of a dose applied to the open skin surface evaporates. Hair has been used as a biopsy material to assess lead exposure. The biological effects of lead poisoning are discussed, including the synergistic effects of lead and agents provoking porphyria.

  2. Stochastic Dynamic Mixed-Integer Programming (SD-MIP)

    Science.gov (United States)

    2015-05-05

    et al (2009), there is continuing interest in using SA methods for SP problems. This genre of methods creates a sequence of sampled subgradients ...an SA algorithm to be a sampled version of the deterministic subgradient method, just as two-stage SD is a sampled version of Benders’ decomposition...advantage of not having to calculate a subgradient using every potential outcome of the random variable. The main point here is that SA and SD are both

  3. EFFECT OF LEAD ACETATE

    African Journals Online (AJOL)

    MICROSOFT

    The project was conducted to evaluate the effect of lead administered as lead acetate at different dosage levels via drinking water in broiler chicks. Thirty-five healthy chicks were divided into seven groups (five chicks each) and one group was kept as un-medicated control. Groups A, B, C, D, E and F were medicated with ...

  4. Leading Acquisition Reform

    Science.gov (United States)

    2011-03-22

    Army and Undersecretary of Defense for Acquisition, for a reduction of the Excalibur and Accelerated Precision Mortar initiative rounds.25...Can’t Dance? Leading a Great Enterprise Through Dramatic Change, (New York: HarperCollins Publishers, 2003), 235. 13 John P. Kotter , Leading Change

  5. Developmental immunotoxicology of lead.

    Science.gov (United States)

    Dietert, Rodney R; Lee, Ji-Eun; Hussain, Irshad; Piepenbrink, Michael

    2004-07-15

    The heavy metal, lead, is a known developmental immunotoxicant that has been shown to produce immune alterations in humans as well as other species. Unlike many compounds that exert adverse immune effects, lead exposure at low to moderate levels does not produce widespread loss of immune cells. In contrast, changes resulting from lead exposure are subtle at the immune cell population level but, nevertheless, can be functionally dramatic. A hallmark of lead-induced immunotoxicity is a pronounced shift in the balance in T helper cell function toward T helper 2 responses at the expense of T helper 1 functions. This bias alters the nature and range of immune responses that can be produced thereby influencing host susceptibility to various diseases. Immunotoxic responses to lead appear to differ across life stages not only quantitatively with regard to dose response, but also qualitatively in terms of the spectrum of immune alterations. Experimental studies in several lab animal species suggest the latter stages of gestation are a period of considerable sensitivity for lead-induced immunotoxicity. This review describes the basic characteristics of lead-induced immunotoxicity emphasizing experimental animal results. It also provides a framework for the consideration of toxicant exposure effects across life stages. The existence of and probable basis for developmental windows of immune hyper-susceptibility are presented. Finally, the potential for lead to serve as a perinatal risk factor for childhood asthma as well as other diseases is considered.

  6. Lead - nutritional considerations

    Science.gov (United States)

    ... lead soldered cans goes into effect. If imported wine containers have a lead foil wrapper, wipe the rim and neck of the bottle with a towel moistened with lemon juice, vinegar, or wine before using. DO NOT store wine, spirits, or ...

  7. Lead toxicity: Current concerns

    Energy Technology Data Exchange (ETDEWEB)

    Goyer, R.A. (Univ. of Western Ontario, London (Canada))

    1993-04-01

    Over the 20-year period since the first issue of Environmental Health Perspectives was published, there has been considerable progress in the understanding of the potential toxicity of exposure to lead. Many of these advances have been reviewed in published symposia, conferences, and review papers in EHP. This brief review identifies major advances as well as a number of current concerns that present opportunities for prevention and intervention strategies. The major scientific advance has been the demonstration that blood lead (PbB) levels of 10-15 micrograms/dL in newborn and very young infants result in cognitive and behavioral deficits. Further support for this observation is being obtained by prospective or longitudinal studies presently in progress. The mechanism(s) for the central nervous system effects of lead is unclear but involve lead interactions within calcium-mediated intracellular messenger systems and neurotransmission. Effects of low-level lead exposure on blood pressure, particularly in adult men, may be related to the effect of lead on calcium-mediated control of vascular smooth muscle contraction and on the renin-angiotensin system. Reproductive effects of lead have long been suspected, but low-level effects have not been well studied. Whether lead is a carcinogen or its association with renal adenocarcinoma is a consequence of cystic nephropathy is uncertain. Major risk factors for lead toxicity in children in the United States include nutrition, particularly deficiencies of essential metals, calcium, iron, and zinc, and housing and socioeconomic status. A goal for the year 2000 is to reduce prevalence of blood lead levels exceeding 15 micrograms/dL. 97 refs.

  8. Fast, Effective Transmitter Placement in Wireless Mesh Networks

    Science.gov (United States)

    2012-01-01

    problem is a nondifferentiable convex optimization problem, to which they ap- ply the subgradient method to obtain a solution. We also apply the... subgradient method to solve this problem, running it only a fixed number of iterations (typically 500) to obtain an approximate solution. Each iteration of the...Gupta (1975) to solve the resource allocation subproblem. Further de- tails of the subgradient algorithm and its imple- mentation to solve this problem

  9. SHORT COMMUNICATION REMOVAL OF LEAD IONS FROM ...

    African Journals Online (AJOL)

    a

    ABSTRACT. A simple cost effective and eco-friendly method for the remediation of lead from industrial wastewater has been investigated. A novel biomaterial, Tridax procumbens (Asteraceae) a medicinal plant, was used for the removal of lead ions from synthetic wastewater and the method was also applied for real sample ...

  10. [A study of the literature on the concentrations of arsenic, lead, cadmium and mercury in body fluids and tissues to define normal values and detection of overload. 1. Description of analytical methods and arsenic].

    Science.gov (United States)

    Baron, P; Schweinsberg, F

    1988-07-01

    The present review covers 208 papers dealing with determination of the metals arsenic, cadmium, lead and mercury in human biologic material. A comprehensive data bank survey of the literature from January 1980 to April 1984 was conducted and supplemented by review of some earlier publications. As shown by comparison of the results from a number of papers, the various state-of-the-art methods for determining metal content in biologic materials (e.g., atomic absorption spectrophotometry, neutron activation analysis, and x-ray fluorescent analysis) appear to be equally sensitive and reliable. These detection methods are suited to determination of the above metals in the following media: arsenic in urine, hair; cadmium in blood, urine, hair, renal cortex; lead in blood, hair; mercury in blood, urine, hair. To permit better comparison of the results presented in various publications, agreement must be reached on use of uniform concentration units and participation in quality control programs. Safe levels of chronic biological exposure overlap with concentrations which cause health effects or measurable impairment of body function over a wide range. Individual sensitivity to biological exposure varies. In a number of studies, metal concentrations are measured in symptom-free persons which cause symptoms in persons examined in other studies. Due to differences in the sensitivity of detection of symptoms, the range of minimum levels of biological exposure considered to be associated with deleterious health effects (levels of critical exposure) is unacceptably broad. Minimum levels of critical exposure should protect against development of early symptoms of toxicity. If the lowest published critical levels of biological exposure are taken as a cutoff, then a sizable portion of the persons currently revealing metal exposure in any of the reported media exceeds such levels. Symptoms of detrimental effects should be detectable in such persons and should be investigated. In

  11. Lead User Innovation

    DEFF Research Database (Denmark)

    Brem, Alexander; Larsen, Henry

    2015-01-01

    User innovation and especially the integration of lead users is a key topic in the innovation management literature of recent years. This paper contributes by providing a rare perspective into what easily could be seen as innovation failure, shown from two perspectives. We show how a lack of shared...... imagination hampers participation and kills innovation between interdependent stakeholders at the threshold between invention and innovation in practice. We present a first case in the fun-sport industry where an external lead user and diverse firm representatives in different functions fail to create......, deliver and capture the value of an innovatively new device together. From the perspective of the lead user, we show antecedents and effects of social interaction between organizational actors and the lead user on the development of social capital, especially trust and shared imagination. The second case...

  12. Leading Your Leaders

    Science.gov (United States)

    Hale, Wayne N.

    2008-01-01

    life is good. More often when an unbelievably difficult test fails, we are left with a very long discussion of why and what was wrong in the design or execution of the test. Make sure that the test is well defined. Even then, it is important to explain to your leaders what inherent accuracy (or error) the test conditions or equipment have and what the assumptions or initial conditions were for the test. Test results without a good understanding of the test's accuracy or the pedigree of the test assumptions are worth very little. Finally, there is flight test data. Always limited, never at the edge of the envelope, it still shows how the real hardware works in a combined environment. Flight experience is dangerous because it typically doesn't show how close to the edge of the cliff the equipment is operating, but it does demonstrate how the hardware really works. A flight test is the ultimate test, again taken with the knowledge that it is probably not the extreme but something more like the middle of the environmental and systems performance. Good understanding of a problem and its solution always relies on a combination of all these methods. Be sure to lead your leaders by using all the tools you have at your disposal. At the end of the day, decisions in space flight always come down to a risk trade. Our business is not remotely safe, not in the sense that the public, the media, or our legislators use the term. Everything we do has a risk, cost, schedule, or performance trade-off. For your leaders to make an appropriate decision, you need to educate them, lead them, talk with them, and engage them in the discussion until full understanding takes place. It's your job. *

  13. Magnesium Diboride Current Leads

    Science.gov (United States)

    Panek, John

    2010-01-01

    A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Dis covered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A. The lead assembly consists of 12 steelclad MgB2 wires, a tensioned Kevlar support, a thermal heat sink interface at 4 K, and base plates. The wires are soldered to heavy copper leads at the 17 K end, and to thin copper-clad NbTi leads at the 1.3 K end. The leads were designed, fabricated, and tested at the Forschungszentrum Karlsruhe - Institut foer Technische Physik before inclusion in Goddard's XRS (X-Ray Spectrometer) instrument onboard the Astro-E2 spacecraft. A key factor is that MgB2 remains superconducting up to 30 K, which means that it does not introduce joule heating as a resistive wire would. Because the required temperature ranges are 1.3-17 K, this provides a large margin of safety. Previous designs lost superconductivity at around 8 K. The disadvantage to MgB2 is that it is a brittle ceramic, and making thin wires from it is challenging. The solution was to encase the leads in thin steel tubes for strength. Previous designs were so brittle as to risk instrument survival. MgB2 leads can be used in any cryogenic application where small currents need to be conducted at below 30 K. Because previous designs would superconduct only at up to 8 K, this new design would be ideal for the 8-30 K range.

  14. How to lead complex situations

    DEFF Research Database (Denmark)

    Hansen, Michael Pingel

    2013-01-01

    The military leader is experiencing increasingly more complex situations, whether it is as leader in a foreign combat environment or in the home-based public administration. Complex situations like these call for a special set of managerial responses and a special way of leading organisations....... The proposition of this article is that the methods that drive innovative processes, strengthening the creative culture, are necessary to manage complex situations in military contexts....

  15. Lead: Aspects of its ecology and environmental toxicity. [physiological effects of lead compound contamination of environment

    Science.gov (United States)

    Siegel, S. M.

    1973-01-01

    An analysis of lead toxicity in the Hawaiian environment was conducted. It was determined that lead enters the environment as an industrial contaminant resulting from the combustion of leaded gasoline. The amount of lead absorbed by the plants in various parts of the Hawaiian Islands is reported. The disposition of lead in the sediments of canals and yacht basins was investigated. The methods for conducting the surveys of lead content are described. Possible consequences of continued environmental pollution by burning leaded gasoline are discussed.

  16. Distributed Convergence to Nash Equilibria in Two-Network Zero-Sum Games

    Science.gov (United States)

    2013-02-17

    convergence of discrete-time subgradient dy- namics to a saddle point. Continuous-time best-response dynamics for zero-sum games converges to the set of...convexity-concavity assumptions, continuous-time subgradient flow dynam- ics converges to a saddle point (Arrow et al., 1951, 1958). Asymptotic convergence...and M. Johansson. A random- ized incremental subgradient method for distributed optimization in networked systems. SIAM Journal on Control and

  17. Lead toxicity in plants

    OpenAIRE

    Sharma, Pallavi; Dubey, Rama Shanker

    2005-01-01

    Contamination of soils by heavy metals is of widespread occurrence as a result of human, agricultural and industrial activities. Among heavy metals, lead is a potential pollutant that readily accumulates in soils and sediments. Although lead is not an essential element for plants, it gets easily absorbed and accumulated in different plant parts. Uptake of Pb in plants is regulated by pH, particle size and cation exchange capacity of the soils as well as by root exudation and other physico-che...

  18. Recent Advances in the Clinical Management of Lead Poisoning

    National Research Council Canada - National Science Library

    Kianoush, Sina; Sadeghi, Mahmood; Balali-Mood, Mahdi

    2015-01-01

    .... This review deals mainly with recent developments in the management of lead poisoning. Sources of lead exposure are introduced, and methods for the primary prevention of lead poisoning are discussed...

  19. Leading through Conflict

    Science.gov (United States)

    Gerzon, Mark

    2006-01-01

    This article talks about leading significant learning opportunities through conflict of ideas in a school system. Catalyzing school change can turn emotional differences of opinion into learning opportunities. Leaders who want to deal effectively with these challenging, often tense situations need to be more than good managers. They need to be…

  20. Turning lead into gold

    DEFF Research Database (Denmark)

    Jensen, Steffen Moltrup Ernø

    For years the field of entrepreneurship has been blinded by the alchemical promise of turning lead into gold, of finding the ones most likely to become the next Branson, Zuckerberg or Gates. The promise has been created in the midst of political and scientific agendas where certain individuals...

  1. Relational Perspectives on Leading

    DEFF Research Database (Denmark)

    Relational Perspectives on Leading discusses leadership from a relational and social constructionism perspective as practiced on an everyday basis between people. The book pursues a fast growing, practice-based approach - particularly within the Anglo-Saxon parts of the world - to organization...

  2. Relational Perspectives on Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    Relational Perspectives on Leading discusses leadership from a relational and social constructionism perspective as practiced on an everyday basis between people. The book pursues a fast growing, practice-based approach - particularly within the Anglo-Saxon parts of the world - to organization...

  3. Revision Surgery of Deep Brain Stimulation Leads.

    Science.gov (United States)

    Falowski, Steven M; Bakay, Roy A E

    2016-07-01

    Deep brain stimulation (DBS) is widely used for various movement disorders. DBS lead revisions are becoming more common as the indications and number of cases increases. Patients undergoing DBS lead revisions at a single institution were retrospectively analyzed based on diagnosis, reason for revision, where the lead was relocated, and surgical technique. We reviewed 497 consecutive DBS lead placements and found that there was need for 25 DBS lead revisions with at least six months of follow-up. Loss of efficacy and development of adverse effects over time were the most common reasons for lead revision across all diagnosis. Lead malfunction was the least common. Ten patients requiring 19 DBS lead revisions that underwent their original surgery at another institution were also analyzed. Surgical technique dictated replacing with a new lead while maintaining brain position and tract with the old lead until final placement. Methods to seal exposed wire were developed. Surgical technique, as well as variable options are important in lead revision and can be dictated based on reason for revision. Over time patients who have had adequate relief with DBS placement may experience loss of efficacy and development of adverse effects requiring revision of the DBS lead to maintain its effects. © 2016 International Neuromodulation Society.

  4. Validation of defibrillator lead performance registry data

    DEFF Research Database (Denmark)

    Kristensen, Anders Elgaard; Larsen, Jacob Moesgaard; Nielsen, Jens Cosedis

    2017-01-01

    AIMS: The validity of registry data on defibrillator lead performance is described only sparsely, despite its clinical importance. This study investigated the validity of defibrillator lead performance registry data in a nationwide and population-based registry. METHODS AND RESULTS: We identified.......9% (95% CI: 85.2-90.2%) with a κ value of 0.82 (95% CI:0.78-0.86) representing an almost perfect match. CONCLUSION: The validity of data on defibrillator lead performance recorded in the DPIR is excellent for the specific types of lead intervention and good for the specific reasons for defibrillator lead...... intervention. The validity of the less detailed overall reasons for lead interventions commonly used to report lead performance is also excellent. These findings indicate high registry data quality appropriate for scientific analysis and industry-independent post-marketing surveillance....

  5. Lead intoxication in Sydney Harbour Bridge workers.

    Science.gov (United States)

    Pollock, C A; Ibels, L S

    1988-02-01

    Thirty-eight Sydney Harbour Bridge workers were assessed for possible lead intoxication. Forty-seven per cent were found to have significant lead intoxication as assessed by calcium disodium edetate chelation (Ca EDTA) testing and were subsequently effectively and safely treated with Ca EDTA. The prevalence of neurological, constitutional, gastrointestinal and musculoskeletal symptoms was significantly greater in those with, than those without, lead toxicity. Although blood lead levels and, to a lesser extent, hematological parameters were of some use in diagnosis, they were not sufficiently sensitive and thus should not be used in screening workers at risk of lead intoxication. Ca EDTA testing remains the diagnostic method of choice. Patients exposed to lead dust and fumes, in whom symptoms of lead intoxication are present, should undergo such testing and if a positive result is obtained, then EDTA chelation therapy should be instituted.

  6. Managing, Leading, and Bossing

    Science.gov (United States)

    2011-08-01

    Defense AT&L: July–August 2011 76 Managing , Leading, and Bossing Stan Emelander Boss Manager Leader Emelander is a project manager in the Army’s...and management . He is level II certified in program management and level I in systems engineering. Leaders fascinate us. From the smallest shop to...me about your boss” will work. Another great question is, “What’s the difference between a leader and a manager ?” Early in my career, I thought there

  7. Lead tungstate scintillation material

    CERN Document Server

    Annenkov, A N; Lecoq, P

    2002-01-01

    In this paper we summarize the results of a research programme on lead-tungstate (PWO) crystals performed by the CMS Collaboration at CERN, as well as by other groups who promoted the progress of the PWO scintillation crystal technology. Crystal properties, mass production technology, scintillation mechanism, origin of colouring, defects in crystal and radiation induced phenomena, light yield improvement and results of beam tests are described. (96 refs).

  8. Problem of lead in petrol: The effect of triethyl lead

    Energy Technology Data Exchange (ETDEWEB)

    Roederer, G.

    1985-10-01

    Triethyl lead is a highly toxic derivate of the anti-knock agent tetraethyl lead. Contrary to anorganic lead compounds triethyl lead causes serious disorders in the central nervous system of poisoned mammals leading to dramatic mental changes. Triethyl lead destroys microtubuli in the cells of plants and animals. It is assumed that the neurotoxic effect of triethyl lead is caused by its interacting with the microtubuli of the nerves (neurotubuli) and their subsequent destruction.

  9. Association of Lead Levels and Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Neha Bansal MD

    2017-03-01

    Full Text Available Background: Cerebral palsy is a common motor disability in childhood. Raised lead levels affect cognition. Children with cerebral palsy may have raised lead levels, further impairing their residual cognitive motor and behavioral abilities. Environmental exposure and abnormal eating habits may lead to increased lead levels. Aims and Objectives: To measure blood lead levels in children with cerebral palsy and compare them with healthy neurologically normal children. To correlate blood lead levels with environmental factors. Material and Methods: Design: Prospective case-control study. Setting: Tertiary care hospital. Participants: Cases comprised 34 children with cerebral palsy, and controls comprised 34 neurologically normal, age- and sex-matched children. Methods: Clinical and demographic details were recorded as per proforma. Detailed environmental history was recorded to know the source of exposure to lead. These children were investigated and treated as per protocol. Venous blood was collected in ethylenediaminetetraacetic acid vials for analysis of blood lead levels. Lead levels were estimated by Schimadzu Flame AA-6800 (atomic absorption spectrophotometer. Data were analyzed using SPSS version 17. P < .05 was taken as significant. Results: Mean blood lead levels were 9.20 ± 8.31 µg/dL in cerebral palsy cases and 2.89 ± 3.04 µg/dL in their controls (P < .001. Among children with cerebral palsy, 19 (55.88% children had blood lead levels ≥5 µg/dL. Lead levels in children with pica were 12.33 ± 10.02 µg/dL in comparison to children with no history of pica, 6.70 ± 4.60 µg/dL (P = .029. No correlation was found between hemoglobin and blood lead levels in cases and controls. Conclusion: In our study, blood lead levels are raised in children with cerebral palsy. However, further studies are required to show effects of raised levels in these children.

  10. The Number of Recalled Leads is Highly Predictive of Lead Failure: Results From the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS").

    Science.gov (United States)

    Kersten, Daniel J; Yi, Jinju; Feldman, Alyssa M; Brahmbhatt, Kunal; Asheld, Wilbur J; Germano, Joseph; Islam, Shahidul; Cohen, Todd J

    2016-12-01

    The purpose of this study was to determine if implantation of multiple recalled defibrillator leads is associated with an increased risk of lead failure. The authors of the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS") have previously reported a relationship between recalled lead status, lead failure, and patient mortality. This substudy analyzes the relationship in a smaller subset of patients who received more than one recalled lead. The specific effects of having one or more recalled leads have not been previously examined. This study analyzed lead failure and mortality of 3802 patients in PAIDLESS and compared outcomes with respect to the number of recalled leads received. PAIDLESS includes all patients at Winthrop University Hospital who underwent defibrillator lead implantation between February 1, 1996 and December 31, 2011. Patients with no recalled ICD leads, one recalled ICD lead, and two recalled ICD leads were compared using the Kaplan-Meier method and log-rank test. Sidak adjustment method was used to correct for multiple comparisons. All calculations were performed using SAS 9.4. P-values leads implanted during the trial period. There were 2400 leads (59%) in the no recalled leads category, 1620 leads (40%) in the one recalled lead category, and 58 leads (1%) in the two recalled leads category. No patient received more than two recalled leads. Of the leads categorized in the two recalled leads group, 12 experienced lead failures (21%), which was significantly higher (Pleads group (60 failures, 2.5%) and one recalled lead group (81 failures; 5%). Multivariable Cox's regression analysis found a total of six significant predictive variables for lead failure including the number of recalled leads (Pleads group). The number of recalled leads is highly predictive of lead failure. Lead-based multivariable Cox's regression analysis produced a total of six predictive variable categories for lead failure, one of which was the number

  11. 29 CFR 1926.62 - Lead.

    Science.gov (United States)

    2010-07-01

    ... of paragraph (d)(10) of this section. (5) Negative initial determination. Where a determination... used to determine methods selected for controlling exposure to lead; (C) A report of the technology... potentially harmful effects of exposure to lead. (vii) The employer shall assure that the containers of...

  12. SQUARE WAVE VOLTAMMETRIC DETERMINATION OF LEAD IN ...

    African Journals Online (AJOL)

    2011-12-31

    Dec 31, 2011 ... ABSTRACT. A simple sensitive square wave voltammetric method for the determination of lead contamination of several kohl samples purchased from Algeria retail stores was developed using glassy carbon electrode. The peak current response of 5 standards aqueous solution of lead in NaNO3 as ...

  13. lead glass brick

    CERN Multimedia

    When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.

  14. Leading change: 2--planning.

    Science.gov (United States)

    Kerridge, Joanna

    National initiatives have outlined the importance of involving frontline staff in service improvement, and the ability to influence and manage change has been identified as an essential skill for delivering new models of care. Nurses often have to take the lead in managing change in clinical practice. The second in a three-part series is designed to help nurses at all levels develop the knowledge and skills to function as change agents within their organisations. This article focuses on planning the change and dealing with resistance.

  15. Association of Lead Levels and Cerebral Palsy.

    Science.gov (United States)

    Bansal, Neha; Aggarwal, Anju; Faridi, M M A; Sharma, Tusha; Baneerjee, B D

    2017-01-01

    Background: Cerebral palsy is a common motor disability in childhood. Raised lead levels affect cognition. Children with cerebral palsy may have raised lead levels, further impairing their residual cognitive motor and behavioral abilities. Environmental exposure and abnormal eating habits may lead to increased lead levels. Aims and Objectives: To measure blood lead levels in children with cerebral palsy and compare them with healthy neurologically normal children. To correlate blood lead levels with environmental factors. Material and Methods:Design: Prospective case-control study. Setting: Tertiary care hospital. Participants: Cases comprised 34 children with cerebral palsy, and controls comprised 34 neurologically normal, age- and sex-matched children. Methods: Clinical and demographic details were recorded as per proforma. Detailed environmental history was recorded to know the source of exposure to lead. These children were investigated and treated as per protocol. Venous blood was collected in ethylenediaminetetraacetic acid vials for analysis of blood lead levels. Lead levels were estimated by Schimadzu Flame AA-6800 (atomic absorption spectrophotometer). Data were analyzed using SPSS version 17. P cerebral palsy cases and 2.89 ± 3.04 µg/dL in their controls (P cerebral palsy, 19 (55.88%) children had blood lead levels ≥5 µg/dL. Lead levels in children with pica were 12.33 ± 10.02 µg/dL in comparison to children with no history of pica, 6.70 ± 4.60 µg/dL (P = .029). No correlation was found between hemoglobin and blood lead levels in cases and controls. Conclusion: In our study, blood lead levels are raised in children with cerebral palsy. However, further studies are required to show effects of raised levels in these children.

  16. A unified treatment of some perturbed fixed point iterative methods with an infinite pool of operators

    Science.gov (United States)

    Nikazad, Touraj; Abbasi, Mokhtar

    2017-04-01

    In this paper, we introduce a subclass of strictly quasi-nonexpansive operators which consists of well-known operators as paracontracting operators (e.g., strictly nonexpansive operators, metric projections, Newton and gradient operators), subgradient projections, a useful part of cutter operators, strictly relaxed cutter operators and locally strongly Féjer operators. The members of this subclass, which can be discontinuous, may be employed by fixed point iteration methods; in particular, iterative methods used in convex feasibility problems. The closedness of this subclass, with respect to composition and convex combination of operators, makes it useful and remarkable. Another advantage with members of this subclass is the possibility to adapt them to handle convex constraints. We give convergence result, under mild conditions, for a perturbation resilient iterative method which is based on an infinite pool of operators in this subclass. The perturbation resilient iterative methods are relevant and important for their possible use in the framework of the recently developed superiorization methodology for constrained minimization problems. To assess the convergence result, the class of operators and the assumed conditions, we illustrate some extensions of existence research works and some new results.

  17. Page 1 250 Jihua Wang et al evaluations, an interleaved ...

    Indian Academy of Sciences (India)

    ers are updated along the direction of the subgradient. Numerical results show that the ISG . method converges much faster than a subgradient method, though algorithm convergence has not yet been established. 3.3e Interleaved conjugate gradient method: As mentioned earlier, the dual function is concave, piece-wise ...

  18. Efficacy of aprons equivalent to 0.5 mm of lead in PET procedures using the Monte Carlo method; Eficacia de aventais equivalentes a 0,5 mm de chumbo em procedimentos PET usando o metodo Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, R.B.; Amaral, A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Campos, L., E-mail: amaral@ufpe.br [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil). Dept. de Fisica

    2012-07-01

    In positron emission tomography (PET), health staff is exposed to 511-keV photons, which is a result of the positron annihilation process. This energy is about four times greater than the 140 keV commonly found in studies based on single photon emission computed tomography (SPECT). Besides this different level of energy, 0.5 mm lead-equivalent aprons have being used either in SPECT or PET procedures. In this context, this work was designed for evaluating the effectiveness of such aprons in individual radioprotection of health professionals involved in positron emission tomography. For this, by using MCNP4C-based Monte Carlo simulations, the average energy delivered per particle to the regions corresponding to operational quantities Hp(10) and Hp(0.07) were calculated for two conditions of individual exposures: wearing and not wearing a 0.05 mm lead-equivalent apron. The results obtained pointed out that Hp(10) has similar value in both situations. On the other hand, for the region corresponding to Hp(0.07), wearing this lead apron will improve this dose in about 26%. On the basis of this work, 0.5 mm lead equivalent aprons do not offer adequate protection for medical staff working on positron emission tomography. (author)

  19. Lead and lead-based alloys as waste matrix materials

    Energy Technology Data Exchange (ETDEWEB)

    Arustamov, A.E.; Ojovan, M.I.; Kachalov, M.B.

    1999-07-01

    Metals and alloys with relatively low melting temperatures such as lead and lead-based alloys are considered in Russia as prospective matrices for encapsulation of spent nuclear fuel in containers in preparation for final disposal in underground repositories. Now lead and lead-based alloys are being used for conditioning spent sealed radioactive sources at radioactive waste disposal facilities.

  20. Theoretical Foundations of Wireless Networks

    Science.gov (United States)

    2015-07-22

    local subproblems in the dual domain. The solution method is through a stochastic subgradient descent algorithm that operates without knowledge of the...solution method is through a stochastic subgradient descent algorithm that operates without knowledge of the fading’s probability distribution and

  1. Human lead metabolism: Chronic exposure, bone lead and physiological models

    Science.gov (United States)

    Fleming, David Eric Berkeley

    Exposure to lead is associated with a variety of detrimental health effects. After ingestion or inhalation, lead may be taken up from the bloodstream and retained by bone tissue. X-ray fluorescence was used to make in vivo measurements of bone lead concentration at the tibia and calcaneus for 367 active and 14 retired lead smelter workers. Blood lead levels following a labour disruption were used in conjunction with bone lead readings to examine the endogenous release of lead from bone. Relations between bone lead and a cumulative blood lead index differed depending on time of hiring. This suggests that the transfer of lead from blood to bone has changed over time, possibly as a result of varying exposure conditions. A common polymorphism in the δ-aminolevulinate dehydratase (ALAD) enzyme may influence the distribution of lead in humans. Blood lead levels were higher for smelter workers expressing the more rare ALAD2 allele. Bone lead concentrations, however, were not significantly different. This implies that a smaller proportion of lead in blood is distributed to tissue for individuals expressing the ALAD2 allele. The O'Flaherty physiological model of lead metabolism was modified slightly and tested with input from the personal exposure histories of smelter workers. The model results were consistent with observation in tern of endogenous exposure to lead and accumulation of lead in cortical bone. Modelling the calcaneus as a trabecular bone site did not reproduce observed trends. variations in lead metabolism between different trabecular sites may therefore be significant. The model does not incorporate a genetic component, and its output did not reflect observed differences in this respect. This result provides further support for the influence of the ALAD polymorphism on lead metabolism. Experimental trials with a digital spectrometer revealed superior energy resolution and count throughput relative to the conventional X-ray fluorescence system. The associated

  2. Method for evaluation of doses from ingestion of polonium, bismuth and lead as natural radioactive material(NORM); Metodo de evaluacion de dosis por ingestion de polonio, bismuto y plomo como materiales radiactivos naturales

    Energy Technology Data Exchange (ETDEWEB)

    Pena, Vanessa; Puerta, Anselmo; Morales, Javier, E-mail: vpenam@ullal.edu.co, E-mail: japuerta@unal.edu.co, E-mail: jmorales@unal.cdu.co [Universidad Nacional de Colombia, Medellin (Colombia). Grupo de Fisica Radiologica

    2013-07-01

    In this work was carried out an evaluation of dose from ingestion of radioactive daughters of radon (lead, bismuth and polonium), taking into account ages from three months up to adult men, using the new model of the human alimentary tract HATM and methodology of calculating doses proposed by the ICRP publication 103, which allows the estimation of dose based on the concentration of the radionuclide present in the diet or in the water of consumption.

  3. Drowning: a leading killer!

    Directory of Open Access Journals (Sweden)

    Nuno Domingos Garrido

    2016-10-01

    Full Text Available Drowning kills at least 372,000 people worldwide every year and is the 3rd leading cause of unintentional death, accounting for 7% of all deaths stemming from accidents (WHO, 2014. Conceptually, “drowning” is a complex and multi-faceted phenomenon, characterized as a chain of events (Bierens, 2006. Drowning is defined as the process of experiencing respiratory impairment from immersion or submersion in liquid. Research on drowning as a phenomenon presents several difficulties - most of all, that global data concerning the number of occurrences are not accurate. Nevertheless, detailed analysis of the registered incidents allows the identification of risk factors of drowning. An in-depth analysis of the risk factors is the basis for the creation of targeted and effective strategies to prevent drowning. Due to variability of situations which could lead to a drowning episode, experts suggest the adoption of a multi-layer prevention model, rather than opting for isolated measures, since no single measure can prevent all deaths and injuries caused by submersion. Among the preventive measures we would like to emphasize instruction in swimming and water safety. So, what does "knowing how to swim" really mean? Some authors define mastery of this competence as swimming a given distance, while others put the emphasis on how this/any given distance is swum (Stallman, Junge, & Blixt, 2008. It has long been realized that there is no contradiction between learning those competencies which make a person less susceptible to drowning and those competencies which prepare the path towards higher levels of performance and competition. Aquatic movement researchers and practitioners and drowning prevention researchers and practitioners, share in the responsibility for drowning prevention though they are often unaware of it. The question “What should be taught to children?” is too infrequently asked. There remains great variation in what is taught and programs

  4. Leading clever people.

    Science.gov (United States)

    Goffee, Rob; Jones, Gareth

    2007-03-01

    In an economy driven by ideas and intellectual know-how, top executives recognize the importance of employing smart, highly creative people. But if clever people have one defining characteristic, it's that they do not want to be led. So what is a leader to do? The authors conducted more than 100 interviews with leaders and their clever people at major organizations such as PricewaterhouseCoopers, Cisco Systems, Novartis, the BBC, and Roche. What they learned is that the psychological relationships effective leaders have with their clever people are very different from the ones they have with traditional followers. Those relationships can be shaped by seven characteristics that clever people share: They know their worth--and they know you have to employ them if you want their tacit skills. They are organizationally savvy and will seek the company context in which their interests are most generously funded. They ignore corporate hierarchy; although intellectual status is important to them, you can't lure them with promotions. They expect instant access to top management, and if they don't get it, they may think the organization doesn't take their work seriously. They are plugged into highly developed knowledge networks, which both increases their value and makes them more of a flight risk. They have a low boredom threshold, so you have to keep them challenged and committed. They won't thank you--even when you're leading them well. The trick is to act like a benevolent guardian: to grant them the respect and recognition they demand, protect them from organizational rules and politics, and give them room to pursue private efforts and even to fail. The payoff will be a flourishing crop of creative minds that will enrich your whole organization.

  5. [Determination of total mercury in fish by means of a digestion method with HNO3/HClO3/HClO4 which does not lead to low results (author's transl)].

    Science.gov (United States)

    Kruse, R

    1979-10-01

    A digestion method for determination of total mercury in fish is described, which is economical, simple and reliable. Digestion is carried out by wet ashing with HNO3/HClO3/HClO4 in the presence of chloric acid. The procedure can be carried out at normal pressure in test tubes without suffering losses of Hg. The determination itself is carried out by the well known cold vapor atomic absorption method. This method was worked out specially for the regulatory control of fish, but can probably be used for related problems.

  6. Leading Public Design

    DEFF Research Database (Denmark)

    Bason, Christian

    In recent years, design has emerged as an approach to shaping public policies and services across industrialized and emerging economies. International institutions, national and local governments, foundations, philanthropies, volunteer and community organizations, and educational institutions...... approaches. More specifically, I confront three questions: • Characterizing design practice: Within public sector organizations, what does the application of design approaches entail? Why do public managers look to and commission design, and what tools, techniques, processes and methods are brought into play...... at all levels have taken up a variety of approaches inspired by the field of design, often in response to growing pressures to innovate. But how these approaches influence public innovation – how they change the roles of public managers, how they help managers generate new ideas and solutions...

  7. Leading with charisma

    Directory of Open Access Journals (Sweden)

    Avbar

    2014-06-01

    Full Text Available Research Question (RQ: Human potential has endless possibilities. Can charisma be taught? What else makes a leader charismatic in the eyes of the followers? Purpose: Purpose and goal of this research paper is to investigate if charisma is human potential that can be learned so leaders could use it to help the population in situations like crisis. We would like to confirm, that charisma is a capability and trait, which can be developed by who ever decides to do so. Method: A descriptive approach was used to examine the theoretical content. Results: To be charismatic means to influence others, connect with them, evoke trust. Charisma is efficient if the leader knows his mission, looks on life difficulties and problems as challenges, is able to be self critic, respects and appreciates others. In the eyes of the followers leader is perceived as charismatic when personal and business vision and goals are established, when present and in control of him/herself and others and in control of the situation. When the leader is showing respect to others and if necessary is decisive and consistent. Organization and society: To unveil the charisma myth, as something god given and unattainable, to the leaders and general public was the aim of this paper. Charisma is not a privilege of some individuals. Leaders have to be aware that it is of most importance to discover this potential and us it for the greater good. Originality: Development of personal charisma is a process, learned from early childhood onwards; some less acquainted with this set of skills can be helped with methods, technique and different approaches. Approaches from various authors are introduced. Limitations/Future Research: This research paper was conducted on articles and books with the key word in title and abstract.

  8. Recent Advances in the Clinical Management of Lead Poisoning.

    Directory of Open Access Journals (Sweden)

    Sina Kianoush

    2015-06-01

    Full Text Available Lead poisoning is a historic universal disease. Acute or chronic lead exposure may cause reversible or even permanent damages in human beings. Environmental lead exposure is a global health concern in children. Occupational lead poisoning is still a health issue, particularly in developing countries. During the last decades, new methods and medications have been advocated for the prevention and treatment of lead poisoning. This review deals mainly with recent developments in the management of lead poisoning. Sources of lead exposure are introduced, and methods for the primary prevention of lead poisoning are discussed. Details for the screening of adults and children are also explained to serve as a practical guideline for the secondary prevention. Standard chelation therapy in different groups and up-to-date less toxic new medications for the treatment of lead poisoning are finally discussed. Our published clinical research on the therapeutic effects of garlic tablets in mild to moderate occupational lead poisoning will also be discussed.

  9. Recent Advances in the Clinical Management of Lead Poisoning.

    Science.gov (United States)

    Kianoush, Sina; Sadeghi, Mahmood; Balali-Mood, Mahdi

    2015-01-01

    Lead poisoning is a historic universal disease. Acute or chronic lead exposure may cause reversible or even permanent damages in human beings. Environmental lead exposure is a global health concern in children. Occupational lead poisoning is still a health issue, particularly in developing countries. During the last decades, new methods and medications have been advocated for the prevention and treatment of lead poisoning. This review deals mainly with recent developments in the management of lead poisoning. Sources of lead exposure are introduced, and methods for the primary prevention of lead poisoning are discussed. Details for the screening of adults and children are also explained to serve as a practical guideline for the secondary prevention. Standard chelation therapy in different groups and up-to-date less toxic new medications for the treatment of lead poisoning are finally discussed. Our published clinical research on the therapeutic effects of garlic tablets in mild to moderate occupational lead poisoning will also be discussed.

  10. BLOOD LEAD CONCENTRATION AND DELAYED PUBERTY IN GIRLS

    Science.gov (United States)

    Background Environmental lead exposure has been linked to alterations in growth and endocrine function. It is not known whether such exposure affects pubertal development.Methods We analyzed the relations between blood lead concentration and pubertal...

  11. Lead Leached into Water from Select Plumbing Fixtures” Could Lead to Health Hazard

    Directory of Open Access Journals (Sweden)

    Ramsey Coles

    2014-01-01

    Full Text Available Background: Lead is an inert metal and is resistant to corrosion. It also increases tensile strength of many common materials in daily use. Lead was used during the Roman period to transport water (hence the name plumbing/plumber is common terminology even in the present day. Lead enters the biological system through the air, water, and dust. Fine particles of lead, having diameter less than 5 nm are directly absorbed by lungs. Inorganic lead is absorbed by the gastrointestinal tract, and organic lead is absorbed by the skin. Lead has long been known to be a toxic heavy metal and exposure is associated with many deleterious health effects. Still, lead remains a popular ingredient in products ranging from paint to batteries. The lead content in any given material is estimated using various methods. The least cumbersome method is found to be X-Ray Fluorescence technique (XRF. A portable XRF device was used in the present study. Aim: The main aim of this study to investigate whether lead is present in various commonly used plumbing materials. Material and Methods: All types of branded and commonly used pipes were gathered from a market in Bangalore and tested using the XRF machine. In order to evaluate to what extent lead from the pipes could leach into water, seven pipes were randomly selected and filled with Aquafina water (having undetectable level of lead for a 24 hour period. This water was tested at an NABL accredited laboratory in Bangalore, India for lead content. Result: It was determined that lead was present in many of the samples, at an unacceptable levels ranging from, well above the globally accepted level of 0.01 mg/L proof that lead was able to leach from the samples into water. Conclusions: As lead in drinking water represents a direct pathway for human exposure, the authors recommend that significant measures be taken to prevent use of lead in the plumbing industry for prevention of it’s deleterious effects. Authors have also

  12. Iodide-assisted total lead measurement and determination of different lead fractions in drinking water samples.

    Science.gov (United States)

    Zhang, Yuanyuan; Ng, Ding-Quan; Lin, Yi-Pin

    2012-07-01

    Lead and its compounds are toxic and can harm human health, especially the intelligence development in children. Accurate measurement of total lead present in drinking water is crucial in determining the extent of lead contamination and human exposure due to drinking water consumption. The USEPA method for total lead measurement (no. 200.8) is often used to analyze lead levels in drinking water. However, in the presence of high concentration of the tetravalent lead corrosion product PbO(2), the USEPA method was not able to fully recover particulate lead due to incomplete dissolution of PbO(2) particles during strong acid digestion. In this study, a new procedure that integrates membrane separation, iodometric PbO(2) measurement, strong acid digestion and ICP-MS measurement was proposed and evaluated for accurate total lead measurement and quantification of different lead fractions including soluble Pb(2+), particulate Pb(II) carbonate and PbO(2) in drinking water samples. The proposed procedure was evaluated using drinking water reconstituted with spiked Pb(2+), spiked particulate Pb(II) carbonate and in situ formed or spiked PbO(2). Recovery tests showed that the proposed procedure and the USEPA method can achieve 93-112% and 86-103% recoveries respectively for samples containing low PbO(2) concentrations (0.018-0.076 mg Pb per L). For samples containing higher concentrations of PbO(2) (0.089-1.316 mg Pb per L), the USEPA method failed to meet the recovery requirement for total lead (85-115%) while the proposed method can achieve satisfactory recoveries (91-111%) and differentiate the soluble Pb(2+), particulate Pb(II) carbonate and PbO(2).

  13. Safety and Health Topics: Lead

    Science.gov (United States)

    ... gray, heavy metal that occurs naturally in the Earth’s crust. Lead was one of the first metals ... even at very low blood lead levels. Pregnant women or those who might become pregnant must avoid ...

  14. Lead Exposure Hazard Management Guide

    Science.gov (United States)

    1993-12-01

    effects of lead on humans beings have been known for many years. Acute overexposure to lead can kill in a matter of days. Chronic overexposure to lead in...8217--: -7 Thserconnsa*Im will help achive one of dh nationial health objectives specified by Healthy Peple 2000, which is to eliminate exposures that

  15. Lead poisoning in an adult: lead mobilization by pregnancy?

    Science.gov (United States)

    Riess, Matthias L; Halm, Josiah K

    2007-08-01

    We report a case of acute lead poisoning in an adult female who had last been exposed to lead 7 years ago. She presented with abdominal pain, knee pain, and neurological symptoms, hypertension, chronic kidney disease, and anemia with basophilic stippling and lead gum lines. Compared to during her recent pregnancy, her lead level had almost tripled in 5 months to 81 mcg/dL. Chelation therapy was initiated and improved the patient's symptoms and lead level significantly. In the absence of any new lead exposure or other reasons for increased bone turnover, this acute lead increase was likely due to skeletal mobilization caused by increased resorption from mineralized tissue during and after her pregnancy. This case report illustrates the seriousness of long-term health effects associated with lead poisoning at a multi-organ level, even years after the initial exposure. Thus, patient care should not be limited to the acute treatment of increased lead levels, but also include prevention of increased mobilization and bone turnover and appropriate patient education. In this context, we review various aspects of lead toxicity, especially during pregnancy and lactation.

  16. Current practice in transvenous lead extraction

    DEFF Research Database (Denmark)

    Bongiorni, Maria Grazia; Blomström-Lundqvist, Carina; Kennergren, Charles

    2012-01-01

    AIM: Current practice with regard to transvenous lead extraction among European implanting centres was analysed by this survey. METHODS AND RESULTS: Among all contacted centres, 164, from 30 countries, declared that they perform transvenous lead extraction and answered 58 questions...... with a compliance rate of 99.9%. Data from the survey show that there seems to be an overall increasing experience of managing various techniques of lead extraction and a widespread involvement of cardiac centres in this treatment. Results and complication rates seem comparable with those of main international...... registries. CONCLUSION: This survey gives an interesting snapshot of lead extraction in Europe today and gives some clues for future research and prospective European registries....

  17. Treating Lead Toxicity: Possibilities beyond Synthetic Chelation

    Directory of Open Access Journals (Sweden)

    Shambhavi Tannir

    2013-01-01

    Full Text Available Lead, a ubiquitous metal, is one of the most abundant elements present on earth. Its easy availability and cost effectiveness made it an extremely popular component in the industrial revolution. However, its hazardous health effects were not considered at the time. Over the last few decades, with the adverse effects of lead coming to the forefront, nations across the world have started to recognize and treat lead toxicity. The most reliable and used method until now has been chelation therapy. Recent research has suggested the use of natural products and sources to treat lead poisoning with minimal or no side effects. This review has tried to summarize a few of the natural products/sources being investigated by various groups.

  18. Performance of lead-free versus lead-based hunting ammunition in ballistic soap.

    Directory of Open Access Journals (Sweden)

    Felix Gremse

    Full Text Available BACKGROUND: Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. METHODS: We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. RESULTS: All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. CONCLUSION: The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion

  19. Soil Lead and Children's Blood Lead Disparities in Pre- and Post-Hurricane Katrina New Orleans (USA).

    Science.gov (United States)

    Mielke, Howard W; Gonzales, Christopher R; Powell, Eric T

    2017-04-12

    This study appraises New Orleans soil lead and children's lead exposure before and ten years after Hurricane Katrina flooded the city. Introduction : Early childhood exposure to lead is associated with lifelong and multiple health, learning, and behavioral disorders. Lead exposure is an important factor hindering the long-term resilience and sustainability of communities. Lead exposure disproportionately affects low socioeconomic status of communities. No safe lead exposure is known and the common intervention is not effective. An essential responsibility of health practitioners is to develop an effective primary intervention. Methods : Pre- and post-Hurricane soil lead and children's blood lead data were matched by census tract communities. Soil lead and blood lead data were described, mapped, blood lead graphed as a function of soil lead, and Multi-Response Permutation Procedures statistics established disparities. Results : Simultaneous decreases occurred in soil lead accompanied by an especially large decline in children's blood lead 10 years after Hurricane Katrina. Exposure disparities still exist between children living in the interior and outer areas of the city. Conclusions : At the scale of a city, this study demonstrates that decreasing soil lead effectively reduces children's blood lead. Primary prevention of lead exposure can be accomplished by reducing soil lead in the urban environment.

  20. Identification of genomic differences between Campylobacter jejuni subsp. jejuni and C. jejuni subsp. doylei at the nap locus leads to the development of a C. jejuni subspeciation multiplex PCR method

    Directory of Open Access Journals (Sweden)

    Heath Sekou

    2007-02-01

    Full Text Available Abstract Background The human bacterial pathogen Campylobacter jejuni contains two subspecies: C. jejuni subsp. jejuni (Cjj and C. jejuni subsp. doylei (Cjd. Although Cjd strains are isolated infrequently in many parts of the world, they are obtained primarily from human clinical samples and result in an unusual clinical symptomatology in that, in addition to gastroenteritis, they are associated often with bacteremia. In this study, we describe a novel multiplex PCR method, based on the nitrate reductase (nap locus, that can be used to unambiguously subspeciate C. jejuni isolates. Results Internal and flanking napA and napB primer sets were designed, based on existing C. jejuni and Campylobacter coli genome sequences to create two multiplex PCR primer sets, nap mpx1 and nap mpx2. Genomic DNA from 161 C. jejuni subsp. jejuni (Cjj and 27 C. jejuni subsp. doylei (Cjd strains were amplified with these multiplex primer sets. The Cjd strains could be distinguished clearly from the Cjj strains using either nap mpx1 or mpx2. In addition, combination of either nap multiplex method with an existing lpxA speciation multiplex method resulted in the unambiguous and simultaneous speciation and subspeciation of the thermophilic Campylobacters. The Cjd nap amplicons were also sequenced: all Cjd strains tested contained identical 2761 bp deletions in napA and several Cjd strains contained deletions in napB. Conclusion The nap multiplex PCR primer sets are robust and give a 100% discrimination of C. jejuni subspecies. The ability to rapidly subspeciate C. jejuni as well as speciate thermophilic Campylobacter species, most of which are pathogenic in humans, in a single amplification will be of value to clinical laboratories in strain identification and the determination of the environmental source of campylobacterioses caused by Cjd. Finally, the sequences of the Cjd napA and napB loci suggest that Cjd strains arose from a common ancestor, providing clues as to

  1. Chronic lead poisoning in horses

    Energy Technology Data Exchange (ETDEWEB)

    Knight, H.D.; Burau, R.G.

    1973-05-01

    Chronic lead poisoning in horses was manifested as anorexia, loss of body weight, muscular weakness, anemia, laryngeal hemiplegia, and, terminally, inhalation pneumonia. Some deaths were sudden and unexplained. The lead content in liver specimens from 10 horses was greater than that considered indicative of lead intoxication; however, the lead content of blood was equivocal. The most conclusive laboratory finding was increased urine lead concentration after chelation therapy. The concentration of lead in a sample of vegetation considered to be representative of what a horse would eat if he was grazing in the area sampled was 325 ppM (oven-dry basis). It was determined that a 450-kg horse grazing grass of this lead content would consume 2.9 Gm of lead daily (6.4 mg/kg of body weight), an amount considered toxic for horses. Leaching lowered the calcium content of the forage but failed to reduce the lead concentration of the plants significantly, thus opening the possibility that winter rains might have influenced the onset of poisoning. Airborne fallout from a nearby lead smelter was proposed as the primary mode of pasture contamination.

  2. Childhood lead poisoning: an overview.

    Science.gov (United States)

    Hon, K L; Fung, C K; Leung, A Kc

    2017-12-01

    Childhood lead poisoning is a major public health concern in many countries. In 2015, the Hong Kong SAR Government and its citizens faced a major public health crisis due to the presence of lead in the drinking water of a number of public housing estates. Fortunately, no child was diagnosed with lead poisoning that required treatment with chelation. Lead is a ubiquitous, naturally occurring material that exists in air, dust, soil, and water. It is also widely present in industrial products including petrol, paints, ceramics, food cans, candies, cosmetics, traditional remedies, batteries, solder, stained glass, crystal vessels, ammunition, ceramic glazes, jewellry, and toys. It can also be found in human milk. There is no safe blood lead level and it may be impossible to completely eliminate lead from any city. Hence routine measurement of blood lead levels is not considered useful. Acute poisoning, especially with encephalopathy, deserves immediate medical treatment in hospital. Chelation therapy is recommended if blood lead level is 45 μg/dL or higher. For blood levels between 20 and 45 μg/dL, treatment is indicated if the child is symptomatic. For blood levels below 20 μg/dL in otherwise asymptomatic children, the principle of treatment is to provide long-term neurodevelopmental follow-up and counselling. In all cases, immediate removal of the source of lead exposure is vital. Even low levels of lead exposure can significantly impair learning, educational attainment, and neurodevelopment.

  3. Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods. Part 5. Effects of nonoriginal surface coatings into the nature and distribution of chromium and sulfur species in chrome yellow paints.

    Science.gov (United States)

    Monico, Letizia; Janssens, Koen; Vanmeert, Frederik; Cotte, Marine; Brunetti, Brunetto Giovanni; Van der Snickt, Geert; Leeuwestein, Margje; Salvant Plisson, Johanna; Menu, Michel; Miliani, Costanza

    2014-11-04

    The darkening of lead chromate yellow pigments, caused by a reduction of the chromate ions to Cr(III) compounds, is known to affect the appearance of several paintings by Vincent van Gogh. In previous papers of this series, we demonstrated that the darkening is activated by light and depends on the chemical composition and crystalline structure of the pigments. In this work, the results of Part 2 are extended and complemented with a new study aimed at deepening the knowledge of the nature and distribution of Cr and S species at the interface between the chrome yellow paint and the nonoriginal coating layer. For this purpose, three microsamples from two varnished paintings by Van Gogh and a waxed low relief by Gauguin (all originally uncoated) have been examined. Because nonoriginal coatings are often present in artwork by Van Gogh and contemporaries, the understanding of whether or not their application has influenced the morphological and/or physicochemical properties of the chrome yellow paint underneath is relevant in view of the conservation of these masterpieces. In all the samples studied, microscopic X-ray fluorescence (μ-XRF) and X-ray absorption near edge structure (μ-XANES) investigations showed that Cr(III)-based alteration products are present in the form of grains inside the coating (generally enriched of S species) and also homogeneously widespread at the paint surface. The distribution of Cr(III) species may be explained by the mechanical friction caused by the coating application by brush that picked up and redistributed the superficial Cr compounds, likely already present in the reduced state as result of the photodegradation process. The analysis of the XANES profiles allowed us to obtain new insights into the nature of the Cr(III) alteration products, that were identified as sulfate-, oxide-, organo-metal-, and chloride-based compounds. Building upon the knowledge acquired through the examination of original paint samples and from the

  4. Lead Contents and Distribution Characteristics of Soils and Vegetables Around an Abandoned Lead Smeltery

    Directory of Open Access Journals (Sweden)

    ZOU Tian-sen

    2016-07-01

    Full Text Available In order to disclose the degree and scope of lead pollution of the abandoned lead smeltery, 102 surface soil samples and 69 vegetables samples were collected by using the method of fan-shaped sampling points around an abandoned lead smeltery in Hubei Province. The lead contents of soils and vegetables were detected by graphite furnace atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry, respectively, and the lead spatial distribution was analyzed. The results showed that the geometric mean of lead contents in soils around the abandoned lead smeltery was 39.8 mg·kg-1 and exceeded the soil background value of Hubei Province(26.7 mg·kg-1. The mean value of geo-accumulation indexes of lead contents in soil was 0.09, and 36.4% of them exceeded zero. The geo-accumulation indexes of sampling distance of 500, 1000 m and 1500 m from the smeltery were 2.11, 0.61 and 0.33, respectively, while the values of sampling distances of more than 2000 m were all less than zero. 24.0%、36.0% and 6.3% of the lead contents exceeded the standard value of limited standards of contaminants in vagetables for cabbage, radish and green onion samples, respectively. The soils and vegetables around the abandonded lead smeltery within 500 m were contaminated seriously. The degree of lead pollution in soils was mild or moderate within 500 m to 2000 m, and the maximum scope in cabbage, radish and green onion was polluted within 500~1000, 1000~1500 m and 500~1000 m, respectively. Lead pollution in vegetables around the abandonded lead smeltery presented obvious characteristics of high pollution and enrichment.

  5. Lead toxicity in battery workers.

    Science.gov (United States)

    Qasim, Saeeda Fouzia; Baloch, Malka

    2014-11-01

    Lead poisoning is a medical condition caused by increased levels of lead in the body. Routes of exposure include contaminated air, water, soil, food and consumer products. Occupational exposure is the main cause of lead poisoning in the adults. Two cases of occupational lead poisoning in adult battery workers are hereby presented. Both male patients had initial non-specific symptoms of intermittent abdominal pain, fatigue and headache for 6 - 8 years. Later on, they developed psychosis, slurred speech, tremors of hands and initially underwent treatment for Parkinsonism and Wilson's disease because of clinical misdiagnosis. They were diagnosed with lead poisoning later and were treated successfully with lead chelator (CaNa2 EDTA).

  6. Taking the Lead : Gender, Social Context and Preference to Lead

    NARCIS (Netherlands)

    Hong, A.P.C.I.; Schaafsma, J.; van der Wijst, P.J.

    Previous research has demonstrated that women tend to emerge as leaders less often than men. In the present study, we examined to what extent women's and men's preference to lead is influenced by social context. It was hypothesized that women have a less strong preference to lead than men in a

  7. Undue Lead Absorption and Lead Poisoning in Children: An Overview.

    Science.gov (United States)

    Lin-Fu, J. S.

    The toxic effects of lead, a useful metal ubiquitous in the human environment, have long been known. The occupational hazards of lead poisoning were well established by the early 19th century, but plumbism in children caused by paint ingestion was not reported until the turn of the century. Even in 1924, the child was said to live in a "lead…

  8. Leading Millennials Motivating And Leading Millennial Service Members

    Science.gov (United States)

    2016-02-20

    AIR WAR COLLEGE AIR UNIVERSITY LEADING MILLENNIALS MOTIVATING AND LEADING MILLENNIAL SERVICE MEMBERS by Joanne MacGregor, LTC...young adults ( Millennials ) serving in the U.S. military. These factors may not be readily apparent to Generation X and Y leaders. This paper argues...motivate, and discipline millennial subordinates while maximizing their talents through active and thoughtful professional development. 5

  9. Strategic Military Leaders - Leading Tomorrow

    Science.gov (United States)

    2008-02-29

    St ra te gy R es ea rc h Pr oj ec t STRATEGIC MILITARY LEADERS –LEADING TOMORROW BY COLONEL NG WAI KIT Singapore Army DISTRIBUTION...Strategic Military Leaders - Leading Tomorrow 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Ng Kit 5d. PROJECT...STRATEGIC MILITARY LEADERS – LEADING TOMORROW by Colonel Ng Wai Kit Singapore Army Dr. Leonard Wong Project

  10. Safe Leads and Lead Changes in Competitive Team Sports

    CERN Document Server

    Clauset, A; Redner, S

    2015-01-01

    We investigate the time evolution of lead changes within individual games of competitive team sports. Exploiting ideas from the theory of random walks, the number of lead changes within a single game follows a Gaussian distribution. We show that the probability that the last lead change and the time of the largest lead size are governed by the same arcsine law, a bimodal distribution that diverges at the start and at the end of the game. We also determine the probability that a given lead is "safe" as a function of its size $L$ and game time $t$. Our predictions generally agree with comprehensive data on more than 1.25 million scoring events in roughly 40,000 games across four professional or semi-professional team sports, and are more accurate than popular heuristics currently used in sports analytics.

  11. Safe leads and lead changes in competitive team sports

    Science.gov (United States)

    Clauset, A.; Kogan, M.; Redner, S.

    2015-06-01

    We investigate the time evolution of lead changes within individual games of competitive team sports. Exploiting ideas from the theory of random walks, the number of lead changes within a single game follows a Gaussian distribution. We show that the probability that the last lead change and the time of the largest lead size are governed by the same arcsine law, a bimodal distribution that diverges at the start and at the end of the game. We also determine the probability that a given lead is "safe" as a function of its size L and game time t . Our predictions generally agree with comprehensive data on more than 1.25 million scoring events in roughly 40 000 games across four professional or semiprofessional team sports, and are more accurate than popular heuristics currently used in sports analytics.

  12. Environmental lead exposure among preschool children in Shanghai, China: blood lead levels and risk factors.

    Directory of Open Access Journals (Sweden)

    Jia Cao

    Full Text Available OBJECTIVE: To determine blood lead levels and to identify related risk factors among children in Shanghai; to explore the lead change trend of children after industrial transformation and to provide data for policy development to control environmental lead pollution in Shanghai. METHODS: A stratified-clustered-random sampling method was used. A tungsten atomizer absorption spectrophotometer was employed to determine blood lead levels. RESULTS: The arithmetic mean, geometric mean and median of blood lead levels of 0- to 6-year-old children from Shanghai were 22.49 µg/L, 19.65 µg/L and 19.5 µg/L, including 0.26% (6/2291 with concentrations ≥100 µg/L and 2.7% (61/2291 with concentrations ≥50 µg/L. Boys' levels (23.57 µg/L were greater than those of girls (21.2 µg/L. The blood lead levels increased with age. This survey showed that the Chongming district was the highest and Yangpu district was the lowest, this result is completely opposite with the earlier survey in Shanghai. Risk factors for lead contamination included housing environment, parents' education levels, social status, hobbies, and children's nutritional status. CONCLUSIONS: The blood lead levels of children in Shanghai were lower than the earlier data of Shanghai and those of published studies in China, but higher than the blood lead levels of developed countries. The blood lead levels of urban districts are higher than the central districts with the industrial transformation. Society and the government should take an active interest in childhood lead poisoning of urban areas.

  13. High temperature superconductor current leads

    Science.gov (United States)

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  14. Lead Poisoning in Wild Birds

    Science.gov (United States)

    Lahner, Lesanna L.; Franson, J. Christian

    2009-01-01

    Lead in its various forms has been used for thousands of years, originally in cooking utensils and glazes and more recently in many industrial and commercial applications. However, lead is a potent, potentially deadly toxin that damages many organs in the body and can affect all animals, including humans. By the mid 1990s, lead had been removed from many products in the United States, such as paint and fuel, but it is still commonly used in ammunition for hunting upland game birds, small mammals, and large game animals, as well as in fishing tackle. Wild birds, such as mourning doves, bald eagles, California condors, and loons, can die from the ingestion of one lead shot, bullet fragment, or sinker. According to a recent study on loon mortality, nearly half of adult loons found sick or dead during the breeding season in New England were diagnosed with confirmed or suspected lead poisoning from ingestion of lead fishing weights. Recent regulations in some states have restricted the use of lead ammunition on certain upland game hunting areas, as well as lead fishing tackle in areas frequented by common loons and trumpeter swans. A variety of alternatives to lead are available for use in hunting, shooting sports, and fishing activities.

  15. Investigation and Evaluation of Children's Blood Lead Levels around a Lead Battery Factory and Influencing Factors.

    Science.gov (United States)

    Zhang, Feng; Liu, Yang; Zhang, Hengdong; Ban, Yonghong; Wang, Jianfeng; Liu, Jian; Zhong, Lixing; Chen, Xianwen; Zhu, Baoli

    2016-05-28

    Lead pollution incidents have occurred frequently in mainland China, which has caused many lead poisoning incidents. This paper took a battery recycling factory as the subject, and focused on measuring the blood lead levels of environmental samples and all the children living around the factory, and analyzed the relationship between them. We collected blood samples from the surrounding residential area, as well as soil, water, vegetables. The atomic absorption method was applied to measure the lead content in these samples. The basic information of the generation procedure, operation type, habit and personal protect equipment was collected by an occupational hygiene investigation. Blood lead levels in 43.12% of the subjects exceeded 100 μg/L. The 50th and the 95th percentiles were 89 μg/L and 232 μg/L for blood lead levels in children, respectively, and the geometric mean was 94 μg/L. Children were stratified into groups by age, gender, parents' occupation, distance and direction from the recycling plant. The difference of blood lead levels between groups was significant (p factory, the higher the value of BLL and lead levels in vegetable and environment samples. The lead level in the environmental samples was higher downwind of the recycling plant.

  16. Atom, atom-type and total molecular linear indices as a promising approach for bioorganic and medicinal chemistry: theoretical and experimental assessment of a novel method for virtual screening and rational design of new lead anthelmintic.

    Science.gov (United States)

    Marrero-Ponce, Yovani; Castillo-Garit, Juan A; Olazabal, Ervelio; Serrano, Hector S; Morales, Alcidez; Castañedo, Nilo; Ibarra-Velarde, Froylán; Huesca-Guillen, Alma; Sánchez, Alicia M; Torrens, Francisco; Castro, Eduardo A

    2005-02-15

    Helminth infections are a medical problem in the world nowadays. In this paper a novel atom-level chemical descriptor has been applied to estimate the anthelmintic activity. Total and local linear indices and linear discriminant analysis were used to obtain a quantitative model that discriminates between anthelmintic and non-anthelmintic drug-like compounds. The discriminant model has an accuracy of 90.11% in the training set, with a high Matthews' correlation coefficient (MCC=0.80). To assess the robustness and predictive power of the obtained model, internal (leave-n-out) and external validation process was performed. The QSAR model correctly classified 88.55% of compounds in this external prediction set, yielding a MCC of 0.77. Another LDA model was carried out to outline some conclusions about the possible modes of action of anthelmintic drugs. It has an accuracy of 93.50% in the training set, and 80.00% in the external prediction set. After that, the developed model was used in the virtual--in silico--screening and several compounds from the Merck Index, Negwer's Handbook and Goodman and Gilman were identified by the model as anthelmintic. Finally, the experimental assay of an organic chemical (a furylethylene derivative) by an in vivo test permits us to carry out an assessment of the model. An accuracy of 100% with the theoretical predictions was observed. These results suggest that the proposed method will be a good tool for studying the biological properties of drug candidates during the early state of the drug-development process.

  17. Lead Exposure: Weighing Down IQ.

    Science.gov (United States)

    Science News, 1979

    1979-01-01

    Researchers at Harvard Medical School and the Children's Hospital Medical Center in Boston have found that children exposed to high but well below identified toxic levels of lead show significantly lower IQ levels and a higher incidence of undesirable classroom behavior than do children with low levels of lead exposure. (Author/BB)

  18. Lead Exposure and Child Behavior.

    Science.gov (United States)

    Sciarillo, William G.; And Others

    1992-01-01

    Provides evidence of detrimental effects of lead exposure on child behavior at levels typical of present-day exposure. Behavior and lead-blood level were examined for 201 African-American children aged 2 through 5 years. A standardized parent report measure and consideration of maternal morale are features of study methodology. (SLD)

  19. Lead poisoning from souvenir earthenware.

    Science.gov (United States)

    Hellström-Lindberg, Eva; Björklund, Andreas; Karlson-Stiber, Christine; Harper, Pauline; Seldén, Anders I

    2006-02-01

    A case of massive lead poisoning from juice contained in a Greek earthenware jug as well as six satellite cases of high lead exposure of similar origin is reported. The intoxicated patient was successfully treated with dimercaptosuccinic acid. Ceramic producers should adhere to the longstanding European legislation.

  20. Lead-free primary explosives

    Science.gov (United States)

    Huynh, My Hang V.

    2010-06-22

    Lead-free primary explosives of the formula (cat).sub.Y[M.sup.II(T).sub.X(H.sub.2O).sub.6-X].sub.Z, where T is 5-nitrotetrazolate, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

  1. Blood Test: Lead (For Parents)

    Science.gov (United States)

    ... Important? Top 10 Homework Tips Raising Confident Kids Blood Test: Lead KidsHealth > For Parents > Blood Test: Lead Print A A A What's in this ... locate a vein Helping Your Child Having a blood test is relatively painless. Still, many children are afraid ...

  2. Oral lead exposure induces dysbacteriosis in rats.

    Science.gov (United States)

    Sadykov, Rustam; Digel, Ilya; Artmann, Aysegül Temiz; Porst, Dariusz; Linder, Peter; Kayser, Peter; Artmann, Gerhard; Savitskaya, Irina; Zhubanova, Azhar

    2009-01-01

    Lead's (Pb(II)) possible role in intestinal pathologies of microbial etiology remains mostly unknown. The aim of this study was to examine the effects of lead on the gut microbial community and its interactions with rat intestinal epithelium. The lead-induced changes in different intestinal microbial groups (lactose-positive lac(+) and -negative lac(-) E.coli strains, lactobacilli and yeasts) were followed separately by the colony-forming unit (CFU) method. Samples were taken from outbred white rats subjected to different exposure schedules. Additionally, the impact of different lead doses on microbial adhesion to cultured intestinal cells (IEC-6) was investigated. Finally, the lead accumulation and distribution were measured by means of atomic absorption spectrometry. For the first time it was shown that oral lead exposure causes drastic changes in the gut microbial community. Proportional to the lead dose received, the relative number of lactose-negative E.coli cells increased dramatically (up to 1,000-fold) in comparison to the other microbial groups during 2 wk of exposure. Considering the number of microbes in the intestine, such a shift in intestinal microflora (dysbacteriosis) is very significant. Adhesion studies showed certain stimulating effects of lead on E. coli attachment to rat intestinal epithelium as compared to Lactobacillus attachment. The mechanisms providing the apparent competitive success of the lac(-) group are unclear but could be related to changes in surface interactions between microbial and host cells. This study may provide important clues for understanding the pathological effects of metal dietary toxins in human beings.

  3. Do newspapers lead with lead? A content analysis of how lead health risks to children are covered.

    Science.gov (United States)

    Brittle, Christine; Zint, Michaela

    2003-06-01

    Lead poses a serious environmental health risk to young children, causing such irreversible health effects as mental retardation, stunted growth, and hearing and visual impairment. Studies suggest that various sectors of the public, including children's caregivers, are not sufficiently concerned about this risk or knowledgeable about ways of minimizing it. Because newspapers are one of the primary ways members of the public learn about risks, the authors examined the characteristics and content of 152 newspaper articles on lead to determine when coverage occurred and what information was provided. Results revealed that newspapers most often covered lead as a local news story. Few articles identified children under six years of age as the most vulnerable group or provided important information on health effects, sources of exposure, or abatement methods. The authors' recommendations focus on helping environmental health professionals work with newspaper journalists to improve the information available to the public.

  4. Collective leadership and safety cultures (Co-Lead): protocol for a mixed-methods pilot evaluation of the impact of a co-designed collective leadership intervention on team performance and safety culture in a hospital group in Ireland.

    Science.gov (United States)

    McAuliffe, Eilish; De Brún, Aoife; Ward, Marie; O'Shea, Marie; Cunningham, Una; O'Donovan, Róisín; McGinley, Sinead; Fitzsimons, John; Corrigan, Siobhán; McDonald, Nick

    2017-11-03

    There is accumulating evidence implicating the role of leadership in system failures that have resulted in a range of errors in healthcare, from misdiagnoses to failures to recognise and respond to patient deterioration. This has led to concerns about traditional hierarchical leadership structures and created an interest in the development of collective ways of working that distribute leadership roles and responsibilities across team members. Such collective leadership approaches have been associated with improved team performance and staff engagement. This research seeks to improve our understanding of collective leadership by addressing two specific issues: (1) Does collective leadership emerge organically (and in what forms) in a newly networked structure? and (2) Is it possible to design and implement collective leadership interventions that enable teams to collectively improve team performance and patient safety? The first phase will include a social network analysis, using an online survey and semistructured interviews at three time points over 12 months, to document the frequency of contact and collaboration between senior hospital management staff in a recently configured hospital group. This study will explore how the network of 11 hospitals is operating and will assess whether collective leadership emerges organically. Second, collective leadership interventions will be co-designed during a series of workshops with healthcare staff, researchers and patient representatives, and then implemented and evaluated with four healthcare teams within the hospital network. A mixed-methods evaluation will explore the impact of the intervention on team effectiveness and team performance indicators to assess whether the intervention is suitable for wider roll-out and evaluation across the hospital group. Favourable ethical opinion has been received from the University College Dublin Research Ethics Committee (HREC-LS-16-116397/LS-16-20). Results will be disseminated

  5. 24 CFR 35.1320 - Lead-based paint inspections, paint testing, risk assessments, lead-hazard screens, and...

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Lead-based paint inspections, paint... Urban Development Office of the Secretary, Department of Housing and Urban Development LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Methods and Standards for Lead-Paint Hazard...

  6. Biosorption of lead phosphates by lead-tolerant bacteria as a mechanism for lead immobilization.

    Science.gov (United States)

    Rodríguez-Sánchez, Viridiana; Guzmán-Moreno, Jesús; Rodríguez-González, Vicente; Flores-de la Torre, Juan Armando; Ramírez-Santoyo, Rosa María; Vidales-Rodríguez, Luz Elena

    2017-08-01

    The study of metal-tolerant bacteria is important for bioremediation of contaminated environments and development of green technologies for material synthesis due to their potential to transform toxic metal ions into less toxic compounds by mechanisms such as reduction, oxidation and/or sequestration. In this study, we report the isolation of seven lead-tolerant bacteria from a metal-contaminated site at Zacatecas, México. The bacteria were identified as members of the Staphylococcus and Bacillus genera by microscopic, biochemical and 16S rDNA analyses. Minimal inhibitory concentration of these isolates was established between 4.5 and 7.0 mM of Pb(NO3)2 in solid and 1.0-4.0 mM of Pb(NO3)2 in liquid media. A quantitative analysis of the lead associated to bacterial biomass in growing cultures, revealed that the percentage of lead associated to biomass was between 1 and 37% in the PbT isolates. A mechanism of complexation/biosorption of lead ions as inorganic phosphates (lead hydroxyapatite and pyromorphite) in bacterial biomass, was determined by Fourier transform infrared spectroscopy and X-ray diffraction analyses. Thus, the ability of the lead-tolerant isolates to transform lead ions into stable and highly insoluble lead minerals make them potentially useful for immobilization of lead in mining waste.

  7. Experimental model of lead nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Khalil-Manesh, F.; Gonick, H.C. (Cedars-Sinai Medical Center, Los Angeles, CA (United States)); Cohen, A. (UCLA-Harbor General Hospital, Torrance, CA (United States)); Bergamaschi, E.; Mutti, A. (Univ. of Parma (Italy))

    1992-06-01

    Male Sprague-Dawley rats were exposed to high-dose (0.5%) lead acetate for periods ranging from 1 to 9 months; then lead exposure was discontinued, and animals were sacrificed after 12 months. Two additional groups of low-dose (0.01%) and high-dose (0.5%) rats were exposed to lead for 6 months, then lead was discontinued and the rats were treated with three 5-day courses of 0.5% DMSA (dimercaptosuccinic acid) over the next 6 months. Low-dose lead-treated rats showed no significant pathological changes with or without DMSA treatment, but exhibited a significant increase in GFR after DMSA. High-dose lead-treated animals showed no functional or pathological changes when lead exposure was discontinued after 1 month. However, when duration of exposure was 6 or 9 months, GFR was decreased and serum creatinine and urea nitrogen were increased as compared to controls. Tubulointerstitial disease was severe. Administration of DMSA resulted in an improvement in GFR and a decrease in albuminuria, together with a reduction in size and number of nuclear inclusion bodies in proximal tubules. However, tubulointerstitial scarring was only minimally reduced. It may be concluded that, except for brief initial exposure, discontinuation of high-dose lead exposure fails to reverse lead-induced renal damage. Treatment with the chelator, DMSA, improves renal function but has less effect on pathological alterations. As GFR improved after DMSA treatment in both low-dose and high-dose lead-treated rats, irrespective of the degree of pathological alterations, it may be concluded that the DMSA effect is most likely mediated by hemodynamic changes.

  8. Evaluation of blood lead level in methamphetamine users in Tehran

    OpenAIRE

    Mostafazadeh, Babak; Shadnia, Shahin; Tavakkoli, Mohammad Ali; Khoddami Vishteh, Hamid Reza

    2017-01-01

    Background Given the increasing number of lead poisoning in opioids users and since no study has been conducted so far to review lead poisoning in methamphetamine (crystal) users, this study aimed to investigate blood lead level in methamphetamine addicts. Methods This study was conducted on 20 patients with methamphetamine poisoning and their blood lead level was measured. The subjects were selected from among patients with a history of continuous use of methamphetamine, without a history of...

  9. Environmental lead hazard to children.

    Science.gov (United States)

    Mittal, S K

    1992-01-01

    Clinically evident lead poisoning is rare in Indian children but is more common than in adults. In children, lead poisoning may appear as fever, seizures, anemia, or abdominal pain, while in adults it is more likely to manifest as chronic minor peripheral neuropathy or gum pigmentation. Children with acute lead poisoning can be treated with chelators such as EDTA and BAL, but many are left with permanent brain damage. The most common sources of acute lead poisoning in Indian children are inhalation of fumes from burned car batteries, ingestion of flaking paint, consuming food cooked in cheap aluminum or brass utensils, and eating contaminated soil. The sources of chronic lead poisoning are water from lead pipes and fumes from industrial or automotive exhaust. Another common source in India is application of "kajjal" to children's eyes. Sources of lead in Western countries, such as drinking water, canned food, residential paint, automotive fuel, and ambient air quality, are regulated by law. None of these are regulated in India.

  10. Correlation between lead in plasma and other indicators of lead exposure among lead-exposed workers.

    Science.gov (United States)

    Hirata, M; Yoshida, T; Miyajima, K; Kosaka, H; Tabuchi, T

    1995-01-01

    In order to clarify the bioavailability of lead in plasma (PbP), we performed a study on five workers in a Japanese factory manufacturing lead glass-based paints. Blood and urine samples were obtained over a period of 15 months, during which time the workers took it in turns to perform sifting work (with the highest level of lead exposure) for 1-month periods. A total of 75 sets of blood and urine samples were thus obtained. We determined whole blood lead (PbB), PbP, Urinary coproporphyrin (CPU), urinary delta-aminolevulinic acid (ALAU), urinary lead (PbU) and ALA in plasma (ALAP). In the 15 sets of samples obtained at the end of the period with a high level of lead exposure, PbP correlated significantly with ALAU, CPU, PbU and ALAP, but PbB correlated significantly only with PbU. In the 60 sets of samples obtained following a low level of lead exposure, correlation coefficients between the concentrations of PbP and of ALAU, CPU and PbU exceeded those between the concentrations of PbB and of ALAU, CPU and PbU. These findings indicate that PbP is a better dose indicator of lead biochemically available for heme synthesis and that PbU has a closer correlation with PbP than with PbB.

  11. REMOVAL OF LEAD IONS FROM INDUSTRIAL WASTE WATER BY ...

    African Journals Online (AJOL)

    A simple cost effective and eco-friendly method for the remediation of lead from industrial wastewater has been investigated. A novel biomaterial, Tridax procumbens (Asteraceae) a medicinal plant, was used for the removal of lead ions from synthetic wastewater and the method was also applied for real sample analysis.

  12. Simultaneous beam sampling and aperture shape optimization for SPORT

    Energy Technology Data Exchange (ETDEWEB)

    Zarepisheh, Masoud; Li, Ruijiang; Xing, Lei, E-mail: Lei@stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States); Ye, Yinyu [Department of Management Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-02-15

    Purpose: Station parameter optimized radiation therapy (SPORT) was recently proposed to fully utilize the technical capability of emerging digital linear accelerators, in which the station parameters of a delivery system, such as aperture shape and weight, couch position/angle, gantry/collimator angle, can be optimized simultaneously. SPORT promises to deliver remarkable radiation dose distributions in an efficient manner, yet there exists no optimization algorithm for its implementation. The purpose of this work is to develop an algorithm to simultaneously optimize the beam sampling and aperture shapes. Methods: The authors build a mathematical model with the fundamental station point parameters as the decision variables. To solve the resulting large-scale optimization problem, the authors devise an effective algorithm by integrating three advanced optimization techniques: column generation, subgradient method, and pattern search. Column generation adds the most beneficial stations sequentially until the plan quality improvement saturates and provides a good starting point for the subsequent optimization. It also adds the new stations during the algorithm if beneficial. For each update resulted from column generation, the subgradient method improves the selected stations locally by reshaping the apertures and updating the beam angles toward a descent subgradient direction. The algorithm continues to improve the selected stations locally and globally by a pattern search algorithm to explore the part of search space not reachable by the subgradient method. By combining these three techniques together, all plausible combinations of station parameters are searched efficiently to yield the optimal solution. Results: A SPORT optimization framework with seamlessly integration of three complementary algorithms, column generation, subgradient method, and pattern search, was established. The proposed technique was applied to two previously treated clinical cases: a head and

  13. Lead poisoning from Ayurvedic medicines.

    Science.gov (United States)

    Tsutsui, Rayji S; Van Schalkwyk, Johan; Spriggs, David

    2013-05-10

    A case of lead poisoning with established exposure to Ayurvedic medicines is presented. This patient migrated from India to New Zealand 8 years previously. He regularly visits India where he purchases "herbal remedies" for his wellbeing.

  14. Simultaneous beam sampling and aperture shape optimization for SPORT.

    Science.gov (United States)

    Zarepisheh, Masoud; Li, Ruijiang; Ye, Yinyu; Xing, Lei

    2015-02-01

    Station parameter optimized radiation therapy (SPORT) was recently proposed to fully utilize the technical capability of emerging digital linear accelerators, in which the station parameters of a delivery system, such as aperture shape and weight, couch position/angle, gantry/collimator angle, can be optimized simultaneously. SPORT promises to deliver remarkable radiation dose distributions in an efficient manner, yet there exists no optimization algorithm for its implementation. The purpose of this work is to develop an algorithm to simultaneously optimize the beam sampling and aperture shapes. The authors build a mathematical model with the fundamental station point parameters as the decision variables. To solve the resulting large-scale optimization problem, the authors devise an effective algorithm by integrating three advanced optimization techniques: column generation, subgradient method, and pattern search. Column generation adds the most beneficial stations sequentially until the plan quality improvement saturates and provides a good starting point for the subsequent optimization. It also adds the new stations during the algorithm if beneficial. For each update resulted from column generation, the subgradient method improves the selected stations locally by reshaping the apertures and updating the beam angles toward a descent subgradient direction. The algorithm continues to improve the selected stations locally and globally by a pattern search algorithm to explore the part of search space not reachable by the subgradient method. By combining these three techniques together, all plausible combinations of station parameters are searched efficiently to yield the optimal solution. A SPORT optimization framework with seamlessly integration of three complementary algorithms, column generation, subgradient method, and pattern search, was established. The proposed technique was applied to two previously treated clinical cases: a head and neck and a prostate case

  15. Spectrochemical determination of lead in wines

    Directory of Open Access Journals (Sweden)

    DRAGAN MARKOVIC

    2000-06-01

    Full Text Available The determination of lead in wines of different origin was performed by means of atomic emission spectroscopy with argon stabilized DC. U-shaped arc and electrothermal atomic absorption spectrometry. The comparison of the results obtained by the direct and standard addition method has indicated the presence of a depressive effect of the complex organic matrix. The effect is avoided successfully by mineralization, as well as by dissolution of the samples. Thus, a relative simple but precise and sensitive method involving the application of a stabilized arc and photoelectric detection with time integration of the emission signals is recommended for the determination of low concentrations of lead in wines. The complex organic matrix was investigated by recording the IR spectra of different wine fractions.

  16. Percutaneous Extraction of Transvenous Permanent Pacemaker/Defibrillator Leads

    Directory of Open Access Journals (Sweden)

    Stylianos Paraskevaidis

    2014-01-01

    Full Text Available Background. Widespread use of cardiovascular implantable electronic devices has inevitably increased the need for lead revision/replacement. We report our experience in percutaneous extraction of transvenous permanent pacemaker/defibrillator leads. Methods. Thirty-six patients admitted to our centre from September 2005 through October 2012 for percutaneous lead extraction were included. Lead removal was attempted using Spectranetics traction-type system (Spectranetics Corp., Colorado, CO, USA and VascoExtor countertraction-type system (Vascomed GmbH, Weil am Rhein, Germany. Results. Lead extraction was attempted in 59 leads from 36 patients (27 men, mean ± SD age 61±5 years, with permanent pacemaker (n=25, defibrillator (n=8, or cardiac resynchronisation therapy (n=3 with a mean ± SD implant duration of 50±23 months. The indications for lead removal included pocket infection (n=23, endocarditis (n=2, and ventricular (n=10 and atrial lead dysfunction (n=1. Traction device was used for 33 leads and countertraction device for 26 leads. Mean ± SD fluoroscopy time was 4±2 minutes/lead for leads implanted 48 months (n=21, P=0.03. Complete procedural success rate was 91.7% and clinical procedural success rate was 100%, while lead procedural success rate was 95%. Conclusions. In conclusion, percutaneous extraction of transvenous permanent pacemaker/defibrillator leads using dedicated removal tools is both feasible and safe.

  17. Ameliorative Effects of Caffeic Acid on Lead Accumulation and Oxidative Stress in Lead-Exposed Mice

    Directory of Open Access Journals (Sweden)

    Maryam Lotfi-Ghahramanloo

    2016-05-01

    Full Text Available Background The currently approved treatment for lead toxicity is chelation therapy to reduce the burden of the toxic effects of lead, but the safety and efficacy of the various chelating agents may be questioned. Objectives This study was aimed to evaluate the effects of caffeic acid, a dietary non-flavonoid phenolic acid, on lead accumulation and lead-induced oxidative stress in mice. Materials and Methods In this experimental study, 24 mice were divided into four groups. Group 1 served as control. Mice in group 2 received water containing 1000 ppm lead acetate. Group 3 animals received caffeic acid (60 mg/kg body weight i.p. during lead treatment. Mice in group 4 only received caffeic acid. At the end of the experiment (18 days, blood samples were drawn and the levels of lead and some oxidative-stress related parameters were measured. Results Blood Pb concentration increased significantly in group 2 as compared to control group. Lead exposure caused significant increase of malondialdehyde and decrease of glutathione concentrations in erythrocyte haemolysate as compared to control group. Although caffeic acid was effective in normalization of the attenuated levels of erythrocytic glutathione, its administration had no significant effect in decreasing the augmented levels of erythrocytic malondialdehyde in group 3. Values of other measured parameters including erythrocytic activities of glutathione peroxidase and superoxide dismutase did not change significantly among experimental groups. Conclusions Present results show some beneficial effects of caffeic acid against lead poisoning and it can be thus proposed as a potential prophylactic treatment for amelioration of lead toxicity.

  18. Anemia risk in relation to lead exposure in lead-related manufacturing

    Directory of Open Access Journals (Sweden)

    Nan-Hung Hsieh

    2017-05-01

    Full Text Available Abstract Background Lead-exposed workers may suffer adverse health effects under the currently regulated blood lead (BPb levels. However, a probabilistic assessment about lead exposure-associated anemia risk is lacking. The goal of this study was to examine the association between lead exposure and anemia risk among factory workers in Taiwan. Methods We first collated BPb and indicators of hematopoietic function data via health examination records that included 533 male and 218 female lead-exposed workers between 2012 and 2014. We used benchmark dose (BMD modeling to estimate the critical effect doses for detection of abnormal indicators. A risk-based probabilistic model was used to characterize the potential hazard of lead poisoning for job-specific workers by hazard index (HI. We applied Bayesian decision analysis to determine whether BMD could be implicated as a suitable BPb standard. Results Our results indicated that HI for total lead-exposed workers was 0.78 (95% confidence interval: 0.50–1.26 with risk occurrence probability of 11.1%. The abnormal risk of anemia indicators for male and female workers could be reduced, respectively, by 67–77% and 86–95% by adopting the suggested BPb standards of 25 and 15 μg/dL. Conclusions We conclude that cumulative exposure to lead in the workplace was significantly associated with anemia risk. This study suggests that current BPb standard needs to be better understood for the application of lead-exposed population protection in different scenarios to provide a novel standard for health management. Low-level lead exposure risk is an occupational and public health problem that should be paid more attention.

  19. Lead level in seminal plasma may affect semen quality for men without occupational exposure to lead

    Directory of Open Access Journals (Sweden)

    Wu Hsien-Ming

    2012-11-01

    Full Text Available Abstract Background Infertility affects approximately 10–15% of reproductive-age couples. Poor semen quality contributes to about 25% of infertile cases. Resulting from the direct effect on testicular function or hormonal alterations, heavy metals exposure has been related to impaired semen quality. The objective of this study was to assess the level of lead in the seminal plasma in men without occupational exposure to lead, and to determine the relationship between semen quality and lead concentration in the semen. Methods This is a prospective and nonrandomized clinical study conducted in University infertility clinic and academic research laboratory. Three hundred and forty-one male partners of infertile couples undergoing infertility evaluation and management were recruited to the study. Semen samples collected for the analyses of semen quality were also used for the measurement of lead concentrations. Semen samples were evaluated according to the WHO standards. Results All subjects were married and from infertile couples without occupational exposure to lead. There is a significant inverse correlation between the lead concentration in seminal plasma and sperm count. A higher semen lead concentration was correlated with lower sperm count, but not with semen volume, sperm motility or sperm morphology as assessed by simple linear regression. Conclusions We found that semen lead concentration was significantly higher among the patients with lower sperm count. To our knowledge, this is the first study to demonstrate that a high level of lead accumulation in semen may reduce the sperm count contributing to infertility of men without occupational exposure to lead.

  20. Projection Methods

    DEFF Research Database (Denmark)

    Wagner, Falko Jens; Poulsen, Mikael Zebbelin

    1999-01-01

    When trying to solve a DAE problem of high index with more traditional methods, it often causes instability in some of the variables, and finally leads to breakdown of convergence and integration of the solution. This is nicely shown in [ESF98, p. 152 ff.].This chapter will introduce projection...... methods as a way of handling these special problems. It is assumed that we have methods for solving normal ODE systems and index-1 systems....

  1. Lead poisoning after gunshot wound

    Directory of Open Access Journals (Sweden)

    Paulo Roberto de Madureira

    2000-05-01

    Full Text Available CONTEXT: Despite the absence of symptoms in the majority of patients carrying lead bullet fragments in their bodies, there needs to be an awareness of the possible signs and symptoms of lead intoxication when bullets are lodged in large joints like knees, hips and shoulders. Such patients merit closer follow-up, and even surgical procedure for removing the fragments. OBJECTIVE: To describe a patient who developed clinical lead intoxication several years after a gunshot wound. DESIGN: Case report. CASE REPORT: A single white 23-year-old male, regular job as a bricklayer, with a history of chronic alcohol abuse, showed up at the emergency department complaining of abdominal pain with colic, weakness, vomiting and diarrhea with black feces. All the symptoms had a duration of two to three weeks, and had been recurrent for the last two years, with calming during interval periods of two to three weeks. Abdominal radiograms showed a bullet lodged in the left hip, with a neat bursogram of the whole synovial capsule. A course of chelating treatment using calcium versenate (EDTACaNa2 intravenously was started. After the chelation therapy the patient had recurrence of his symptoms and a radical solution for the chronic mobilization of lead was considered. A hip arthroplasty procedure was performed, leading to complete substitution of the left hip.

  2. Blood lead level as biomarker of environmental lead pollution in ...

    African Journals Online (AJOL)

    Research has demonstrated a positive link between the presence of lead in freshwater, sediments or food organisms and the onset of sub-lethal effects characterized by neurological defects, kidney dysfunction, endocrine disruption, reproductive/developmental defects, behavioural abnormalities and anemia in demersal ...

  3. Lead Contamination and Microbial Lead Tolerance in Soils at Major ...

    African Journals Online (AJOL)

    Devika

    effects of combined metals (lead, zinc, copper, manganese, iron) showed that at lower concentrations, metals ... battery manufacturing operations (Atuanya et al.,. 1999; Fagade and Adetutu, 1999). This study examined ... Soil samples for analyses were air-dried, sieved through a 2mm sieve and weighed. Microbial Isolation: ...

  4. CAN FLUORIDATION AFFECT WATER LEAD LEVELS AND LEAD NEUROTOXICITY?

    Science.gov (United States)

    Recent reports have attempted to show that certain approaches to fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of nexafluo...

  5. Lead exposure in US worksites: A literature review and development of an occupational lead exposure database from the published literature

    Science.gov (United States)

    Koh, Dong-Hee; Locke, Sarah J.; Chen, Yu-Cheng; Purdue, Mark P.; Friesen, Melissa C.

    2016-01-01

    Background Retrospective exposure assessment of occupational lead exposure in population-based studies requires historical exposure information from many occupations and industries. Methods We reviewed published US exposure monitoring studies to identify lead exposure measurement data. We developed an occupational lead exposure database from the 175 identified papers containing 1,111 sets of lead concentration summary statistics (21% area air, 47% personal air, 32% blood). We also extracted ancillary exposure-related information, including job, industry, task/location, year collected, sampling strategy, control measures in place, and sampling and analytical methods. Results Measurements were published between 1940 and 2010 and represented 27 2-digit standardized industry classification codes. The majority of the measurements were related to lead-based paint work, joining or cutting metal using heat, primary and secondary metal manufacturing, and lead acid battery manufacturing. Conclusions This database can be used in future statistical analyses to characterize differences in lead exposure across time, jobs, and industries. PMID:25968240

  6. Inadvertent transarterial pacemaker lead placement

    Directory of Open Access Journals (Sweden)

    Ravi R. Bajaj

    2015-09-01

    Full Text Available We present a case of a 73-year-old patient with acute left-sided hemiparesis four months after right ventricular pacemaker insertion. Post-procedural electrocardiogram revealed a paced RBBB complex and an abnormal lead path on chest X-ray. Subsequent echocardiography and computed tomography showed left ventricular pacemaker malposition with retrograde passage to the punctured subclavian artery. We also discuss the utility of routine cardiac investigations post-insertion to identify signal lead malposition as well as management strategies once identified.

  7. OPAL 96 Blocks Lead Glass

    CERN Multimedia

    This array of 96 lead glass bricks formed part of the OPAL electromagnetic calorimeter. One half of the complete calorimeter is shown in the picture above. There were 9440 lead glass counters in the OPAL electromagnetic calorimeter. These are made of Schott type SF57 glass and each block weighs about 25 kg and consists of 76% PbO by weight. Each block has a Hamamatsu R2238 photomultiplier glued on to it. The complete detector was in the form of a cylinder 7m long and 6m in diameter. It was used to measure the energy of electrons and photons produced in LEP interactions.

  8. Chronic lead intoxication; Chronische Bleiintoxikation

    Energy Technology Data Exchange (ETDEWEB)

    Wieseler, B.; Leng, G. [Duesseldorf Univ. (Germany). Inst. fuer Hygiene; Lenz, S.; Schultz, C. [Klinikum Remscheid GmbH, Remscheid (Germany); Wilhelm, M. [Bochum Univ. (Germany). Inst. fuer Hygiene, Sozial- und Umweltmedizin

    1999-02-01

    The case of a female 68 years old patient is described. Here, a chronic lead intoxication was diagnosed after a two year old medical history with increasing attacks of colic-like abdominal pain often described as life-threatening. After repeated hospitalizations and intensive search for the cause of the symptoms, porphyria and anemia was found to be a sign of a chronic lead poisoning. The blood lead concentrations were always about a level of 600 {mu}g/L. The source of exposure could not be found by now. Neither home inspection nor environmental investigations have shown a recent source of lead intake by the patient. However, a possible occupational source of lead exposure at a blast furnace was established by anamnesis for 1952 to 1962. Thus, osteoporosis induced lead mobilisation was suspected. Noticeable are the results of the six abdominal survey radiographies taken during hospitalization within one year; three radiographies were taken following clinical admission and three before discharge of the patient. In comparison, the course shows a chronic relapsing alimentary supply from metallic particles of unknown genesis. The patient was treated with the sodium salt of 2,3-dimercapto-1-propansulfonic acid (DMPS, Dimaval{sup TM}). She was free of complain afterwards. Following therapy, the blood lead concentrations fell under a level of 400 {mu}m/L, but after several weeks the lead level raised up to the original level of 600 {mu}g/L. (orig.) [Deutsch] Es wird eine 68jaehrige Patientin vorgestellt, bei der nach fast zweijaehriger Krankengeschichte, die gekennzeichnet war durch rezidivierende, teils als lebensbedrohlich geschilderte Bauchkoliken, eine chronische Bleiintoxikation diagnostiziert wurde. Erst nach wiederholten stationaeren Krankenhausaufenthalten mit intensiver Suche nach der Krankheitsursache wurden das Krankheitsbild und die Laborwerte durch Zusatzuntersuchungen ergaenzt, so dass sich in der festgestellten Porphyrie und Anaemie die Diagnose der

  9. Registered Nurses Leading Innovative Changes

    Science.gov (United States)

    Thomas, Timothy W; Seifert, Patricia C; Joyner, Jane Clare

    2016-09-30

    As innovators, all registered nurses (RNs) act as agents of change to drive processes and policy and leverage technology to prove better, more affordable care for individuals and the community. The authors consider examples of RNs leading innovative ideas and practices to create new knowledge; develop healthcare policies and practices; improve the quality of care; and advance health information technology. This article describes a number of key innovation goals identified by the American Nurses Association Professional Issues Panel, Barriers to RN Scope of Practice, discusses relevant literature related to overcoming barriers to innovation, and identifies recommendations for leading innovative change to achieve innovation goals.

  10. Leading in a Technological Age

    Science.gov (United States)

    Yadgir, Sheri A.

    2011-01-01

    Technology is advancing more rapidly than at any time in history since the beginning of the Industrial Revolution. In fact, experts say that the world is leaving the Industrial Age of the 20th century and entering an Information Age that will lead into the future. These advances mean that important changes are being made in all areas of life--and…

  11. OPAL Various Lead Glass Blocks

    CERN Multimedia

    These lead glass blocks were part of a CERN detector called OPAL (one of the four experiments at the LEP particle detector). OPAL uses some 12 000 blocks of glass like this to measure particle energies in the electromagnetic calorimeter. This detector measured the energy deposited when electrons and photons were slowed down and stopped.

  12. Blood Lead and Reading Readiness

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-08-01

    Full Text Available Investigators at the University of Maryland School of Nursing, Johns Hopkins School of Public Health, and Department of Health, Providence, Rhode Island, evaluated the relationship between reading readiness test scores for children attending public kindergarten in Providence, RI, and state health department records of blood lead levels (BLLs.

  13. Developments in lead-acid batteries: a lead producer's perspective

    Science.gov (United States)

    Frost, P. C.

    Rapid progress is being made in many aspects of materials, design and construction for lead-acid batteries. Much of this work has taken place under the auspices of the Advanced Lead-Acid Battery Consortium (ALABC). From the general tone of the literature, it seems likely that several of these developments will be adopted in commercial products, and that there will be cross-fertilization between the emerging electric vehicle (EV) battery technology and the starting, lighting and ignition (SLI) battery. Given the impetus for improvement from several different factors, the development process appears to be accelerating. To those not intimately involved in the battery design and specification process, it is not clear which of the possible developments will make it from the laboratory to general commercial adoption. Some of the possible changes in materials, design and construction could have an impact on the recovery, recycling, smelting and refining of lead-acid batteries. Some of the possible developments are outlined and their possible impact is discussed. It is likely that negative effects may be minimized if battery developments are considered from other perspectives, largely based on the overall life-cycle, as early in the design phase of new products as possible. Three strategies for minimizing undesirable effects are advocated: first, improved communication between car manufacturers, battery manufacturers and lead producers second, use of life-cycle analysis (LCA) to identify and optimize all attributes of the product throughout its life-cycle third, concerted and coordinated action to deal with issues important to the industry once trends are identified.

  14. Lead-antimony alloys for electrode supports for lead accumulators

    Energy Technology Data Exchange (ETDEWEB)

    Dalibard, G.; Viaud, N.

    1984-04-17

    The grain size and resistance to corrosion of lead-antimony alloys containing less than 4% of antimony and 0.005 to 0.1% copper, are improved by incorporating therein from 0.001 to 0.1% of a mixture of rare earths, preferably misch metal. The alloys may also contain up to 0.5% arsenic or up to 0.8% of tin.

  15. Lead and Drinking Water from Private Wells

    Science.gov (United States)

    ... type=”submit” value=”Submit” /> Healthy Water Home Lead and Drinking Water from Private Wells Recommend on ... remove lead from my drinking water? What is lead? Lead is a naturally occurring bluish-gray metal ...

  16. From drug target to leads--sketching a physicochemical pathway for lead molecule design in silico.

    Science.gov (United States)

    Shaikh, S A; Jain, T; Sandhu, G; Latha, N; Jayaram, B

    2007-01-01

    The discovery of new pharmaceuticals via computer modeling is one of the key challenges in modern medicine. The advent of global networks of genomic, proteomic and metabolomic endeavors is ushering in an increasing number of novel and clinically important targets for screening. Computational methods are anticipated to play a pivotal role in exploiting the structural and functional information to understand specific molecular recognition events of the target macromolecule with candidate hits leading ultimately to the design of improved leads for the target. In this review, we sketch a system independent, comprehensive physicochemical pathway for lead molecule design focusing on the emerging in silico trends and techniques. We survey strategies for the generation of candidate molecules, docking them with the target and ranking them based on binding affinities. We present a molecular level treatment for distinguishing affinity from specificity of a ligand for a given target. We also discuss the significant aspects of drug absorption, distribution, metabolism, excretion and toxicity (ADMET) and highlight improved protocols required for higher quality and throughput of in silico methods employed at early stages of discovery. We present a realization of the various stages in the pathway proposed with select examples from the literature and from our own research to demonstrate the way in which an iterative process of computer design and validation can aid in developing potent leads. The review thus summarizes recent advances and presents a viewpoint on improvements envisioned in the years to come for automated computer aided lead molecule discovery.

  17. Lead-elevated activity of xanthine oxidase in lead-exposed workers

    Directory of Open Access Journals (Sweden)

    Sławomir Kasperczyk

    2013-04-01

    Full Text Available Background: The aim of the present study was to explore the connection between lead toxicity and the activity of xanthine oxidase (XO. In addition, we indicated the uric acid (UA and creatinine levels and concentration of erythrocyte malondialdehyde (MDA to estimate oxidative stress intensity. Materials and Methods: The examined group consisted of 125 healthy male employees of zinc and lead works. The examined group was divided into tertiles according to blood lead levels. In the collected blood samples, concentrations of lead-exposure indices, UA, creatinine, and MDA as well as activity of XO were measured concomitantly. The control group consisted of 32 healthy male administrative workers who were exposed to lead only environmentally. Results: XO activity and MDA level were significantly elevated in all tertiles compared to the control group. Creatinine level was significantly elevated in the medium and high tertiles. However, the level of UA was significantly elevated in the high tertile, while in the low and medium tertile only a tendency toward higher values was observed. Conclusions: Occupational exposure to lead induces activity of XO. This induction may contribute to the observed simultaneously increased oxidative stress, measured as MDA level, and the increased level of UA. Med Pr 2013;64(2:175–180

  18. [Lead poisoning: towards a paleo-epidemiologic re-interpretation?].

    Science.gov (United States)

    Bourdieu, Anne

    2014-01-01

    Lead is a major public health issue. Its use has been increasing since Neolithic times, climaxing in the Ancient Rome and the nineteenth century. Defining the frequency of plumbism before modern times proves to be a difficult matter because of its various and delayed symptoms, and of diagenetic processes affecting bones. After reviewing various methods of lead measurement in bone and tooth, we will expose ways to ascertain lead measurement interpretation in order to estimate the epidemiology of plumbism in ancient times.

  19. Determination of Lead in Blood by Atomic Absorption Spectrophotometry1

    Science.gov (United States)

    Selander, Stig; Cramér, Kim

    1968-01-01

    Lead in blood was determined by atomic absorption spectrophotometry, using a wet ashing procedure and a procedure in which the proteins were precipitated with trichloroacetic acid. In both methods the lead was extracted into isobutylmethylketone before measurement, using ammonium pyrrolidine dithiocarbamate as chelator. The simpler precipitation procedure was shown to give results identical with those obtained with the ashing technique. In addition, blood specimens were examined by the precipitation method and by spectral analysis, which method includes wet ashing of the samples, with good agreement. All analyses were done on blood samples from `normal' persons or from lead-exposed workers, and no additions of inorganic lead were made. The relatively simple protein precipitation technique gave accurate results and is suitable for the large-scale control of lead-exposed workers. PMID:5663425

  20. Antiviral lead compounds from marine sponges.

    Science.gov (United States)

    Sagar, Sunil; Kaur, Mandeep; Minneman, Kenneth P

    2010-10-11

    Marine sponges are currently one of the richest sources of pharmacologically active compounds found in the marine environment. These bioactive molecules are often secondary metabolites, whose main function is to enable and/or modulate cellular communication and defense. They are usually produced by functional enzyme clusters in sponges and/or their associated symbiotic microorganisms. Natural product lead compounds from sponges have often been found to be promising pharmaceutical agents. Several of them have successfully been approved as antiviral agents for clinical use or have been advanced to the late stages of clinical trials. Most of these drugs are used for the treatment of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). The most important antiviral lead of marine origin reported thus far is nucleoside Ara-A (vidarabine) isolated from sponge Tethya crypta. It inhibits viral DNA polymerase and DNA synthesis of herpes, vaccinica and varicella zoster viruses. However due to the discovery of new types of viruses and emergence of drug resistant strains, it is necessary to develop new antiviral lead compounds continuously. Several sponge derived antiviral lead compounds which are hoped to be developed as future drugs are discussed in this review. Supply problems are usually the major bottleneck to the development of these compounds as drugs during clinical trials. However advances in the field of metagenomics and high throughput microbial cultivation has raised the possibility that these techniques could lead to the cost-effective large scale production of such compounds. Perspectives on biotechnological methods with respect to marine drug development are also discussed.

  1. Antiviral Lead Compounds from Marine Sponges

    Directory of Open Access Journals (Sweden)

    Kenneth P. Minneman

    2010-10-01

    Full Text Available Marine sponges are currently one of the richest sources of pharmacologically active compounds found in the marine environment. These bioactive molecules are often secondary metabolites, whose main function is to enable and/or modulate cellular communication and defense. They are usually produced by functional enzyme clusters in sponges and/or their associated symbiotic microorganisms. Natural product lead compounds from sponges have often been found to be promising pharmaceutical agents. Several of them have successfully been approved as antiviral agents for clinical use or have been advanced to the late stages of clinical trials. Most of these drugs are used for the treatment of human immunodeficiency virus (HIV and herpes simplex virus (HSV. The most important antiviral lead of marine origin reported thus far is nucleoside Ara-A (vidarabine isolated from sponge Tethya crypta. It inhibits viral DNA polymerase and DNA synthesis of herpes, vaccinica and varicella zoster viruses. However due to the discovery of new types of viruses and emergence of drug resistant strains, it is necessary to develop new antiviral lead compounds continuously. Several sponge derived antiviral lead compounds which are hopedto be developed as future drugs are discussed in this review. Supply problems are usually the major bottleneck to the development of these compounds as drugs during clinical trials. However advances in the field of metagenomics and high throughput microbial cultivation has raised the possibility that these techniques could lead to the cost-effective large scale production of such compounds. Perspectives on biotechnological methods with respect to marine drug development are also discussed.

  2. Antiviral lead compounds from marine sponges

    KAUST Repository

    Sagar, Sunil

    2010-10-11

    Marine sponges are currently one of the richest sources of pharmacologically active compounds found in the marine environment. These bioactive molecules are often secondary metabolites, whose main function is to enable and/or modulate cellular communication and defense. They are usually produced by functional enzyme clusters in sponges and/or their associated symbiotic microorganisms. Natural product lead compounds from sponges have often been found to be promising pharmaceutical agents. Several of them have successfully been approved as antiviral agents for clinical use or have been advanced to the late stages of clinical trials. Most of these drugs are used for the treatment of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). The most important antiviral lead of marine origin reported thus far is nucleoside Ara-A (vidarabine) isolated from sponge Tethya crypta. It inhibits viral DNA polymerase and DNA synthesis of herpes, vaccinica and varicella zoster viruses. However due to the discovery of new types of viruses and emergence of drug resistant strains, it is necessary to develop new antiviral lead compounds continuously. Several sponge derived antiviral lead compounds which are hopedto be developed as future drugs are discussed in this review. Supply problems are usually the major bottleneck to the development of these compounds as drugs during clinical trials. However advances in the field of metagenomics and high throughput microbial cultivation has raised the possibility that these techniques could lead to the cost-effective large scale production of such compounds. Perspectives on biotechnological methods with respect to marine drug development are also discussed. 2010 by the authors; licensee MDPI.

  3. Deformation properties of lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Tolokonnikov, S. V.; Borzov, I. N.; Lutostansky, Yu. S.; Saperstein, E. E., E-mail: saper43-7@mail.ru [National Research Center Kurchatov Institute (Russian Federation)

    2016-01-15

    The deformation properties of a long lead isotopic chain up to the neutron drip line are analyzed on the basis of the energy density functional (EDF) in the FaNDF{sup 0} Fayans form. The question of whether the ground state of neutron-deficient lead isotopes can have a stable deformation is studied in detail. The prediction of this deformation is contained in the results obtained on the basis of the HFB-17 and HFB-27 Skyrme EDF versions and reported on Internet. The present analysis reveals that this is at odds with experimental data on charge radii and magnetic moments of odd lead isotopes. The Fayans EDF version predicts a spherical ground state for all light lead isotopes, but some of them (for example, {sup 180}Pb and {sup 184}Pb) prove to be very soft—that is, close to the point of a phase transition to a deformed state. Also, the results obtained in our present study are compared with the predictions of some other Skyrme EDF versions, including SKM*, SLy4, SLy6, and UNE1. By and large, their predictions are closer to the results arising upon the application of the Fayans functional. For example, the SLy4 functional predicts, in just the same way as the FaNDF{sup 0} functional, a spherical shape for all nuclei of this region. The remaining three Skyrme EDF versions lead to a deformation of some light lead isotopes, but their number is substantially smaller than that in the case of the HFB-17 and HFB-27 functionals. Moreover, the respective deformation energy is substantially lower, which gives grounds to hope for the restoration of a spherical shape upon going beyond the mean-field approximation, which we use here. Also, the deformation properties of neutron-rich lead isotopes are studied up to the neutron drip line. Here, the results obtained with the FaNDF{sup 0} functional are compared with the predictions of the HFB-17, HFB-27, SKM*, and SLy4 Skyrme EDF versions. All of the EDF versions considered here predict the existence of a region where neutron

  4. Leading Hadron Production at HERA

    Directory of Open Access Journals (Sweden)

    Buniatyan Armen

    2013-06-01

    Full Text Available Data from the recent measurements of very forward baryon and photon production with the H1 and ZEUS detectors at electron-proton collider HERA are presented and compared to the theoretical calculations and Monte Carlo models. Results are presented of the production of leading protons, neutrons and photons in deep inelastic scattering (ep → e' pX, ep → e'nX, ep → e'γX as well as the leading neutron production in the photoproduction of dijets (ep → ejjXn. The forward baryon and photon results from the H1 and ZEUS Experiments are compared also with the models of the hadronic interactions of high energy Cosmic Rays. The sensitivity of the HERA data to the differences between the models is demonstrated.

  5. Lead distribution in soils impacted by a secondary lead smelter: Experimental and modelling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Arnaud R., E-mail: arnaud.schneider@univ-reims.fr [GEGENAA, EA 3795, Université de Reims Champagne-Ardenne, SFR Condorcet FR CNRS 3417, 2 esplanade Roland Garros, 51100 Reims (France); Cancès, Benjamin; Ponthieu, Marie [GEGENAA, EA 3795, Université de Reims Champagne-Ardenne, SFR Condorcet FR CNRS 3417, 2 esplanade Roland Garros, 51100 Reims (France); Sobanska, Sophie [Laboratoire de Spectrochimie IR et Raman, UMR-CNRS 8516, Bât. C5 Université de Lille I, 59655 Villeneuve d' Ascq Cedex (France); Benedetti, Marc F. [Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154, CNRS, F-75005 Paris (France); Pourret, Olivier [HydrISE, Institut Polytechnique LaSalle Beauvais, FR-60000 Beauvais (France); Conreux, Alexandra; Calandra, Ivan; Martinet, Blandine; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice [GEGENAA, EA 3795, Université de Reims Champagne-Ardenne, SFR Condorcet FR CNRS 3417, 2 esplanade Roland Garros, 51100 Reims (France)

    2016-10-15

    Smelting activities are one of the most common sources of trace elements in the environment. The aim of this study was to determine the lead distribution in upper horizons (0–5 and 5–10 cm) of acidic soils in the vicinity of a lead-acid battery recycling plant in northern France. The combination of chemical methods (sequential extractions), physical methods (Raman microspectroscopy and scanning electron microscopy with an energy dispersive spectrometer) and multi-surface complexation modelling enabled an assessment of the behaviour of Pb. Regardless of the studied soil, none of the Pb-bearing phases commonly identified in similarly polluted environments (e.g., anglesite) were observed. Lead was mainly associated with organic matter and manganese oxides. The association of Pb with these soil constituents can be interpreted as evidence of Pb redistribution in the studied soils following smelter particle deposition. - Highlights: • Lead behavior was studied in smelter impacted soils. • A combination of experimental methods and modelling was employed. • Pb was mainly associated with organic matter and to a lesser degree with Mn oxides. • Pb was redistributed in soils after smelter particle deposition.

  6. Anthropogenic lead isotopes in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, K.J.R.; Chisholm, W. [Curtin Univ. of Technology, Bentley (Australia); Boutron, C.F. [Laboratoire de Glaciologie et Geophysique de l`Environnement du CNRS, St. Martin d`Heres (France)]|[Domaine Universitaire, Grenoble (France); Candelone, J.P. [Laboratoire de Glaciologie et Geophysique de l`Environnement du CNRS, St. Martin d`Heres (France); Patterson, C.C. [California Institute of Technology, Pasadena, CA (United States)

    1994-12-01

    The authors present results from the first Pb isotopic study of the sources of lead in snow samples from the Antarctic. Samples of recent snow fields were compared with measurements of samples taken from deep cores, and they reveal that recent snows show pronounced influence of anthropogenic sources. These results are independent of geochemical arguments based on influences of Al, Na, or SO{sub 4}.

  7. Picornavirus infection leading to immunosuppression

    OpenAIRE

    Cusick, Matthew F; Libbey, Jane E.; Fujinami, Robert S.

    2014-01-01

    Viruses, such as HIV, hepatitis A, poliovirus, coxsackievirus B3 and foot-and-mouth disease virus, use a variety of mechanisms to suppress the human immune system in order to evade clearance by the host. Therefore, investigating how a few changes in the viral genome of a nonlethal virus can lead to an alteration in disease, from survivable to immunosuppression and death, would provide valuable information into viral pathogenesis. In addition, we propose that gaining a better insight into how ...

  8. Leading Indian Business-Groups

    Directory of Open Access Journals (Sweden)

    Maria Alexandrovna Vorobyeva

    2016-01-01

    Full Text Available The goal of this paper is to investigate the evolution of the leading Indian business-groups under the conditions of economical liberalization. It is shown that the role of modern business-groups in the Indian economy is determined by their high rate in the gross domestic product (GDP, huge overall actives, substantial pert in the e[port of goods and services, as well as by their activities in modern branch structure formatting, and developing labor-intensive and high-tech branches. They strongly influence upon economical national strategies, they became a locomotive of internationalization and of transnationalization of India, the basis of the external economy factor system, the promoters of Indian "economical miracle" on the world scene, and the dynamical segment of economical and social development of modern India. The tendencies of the development of the leading Indian business groups are: gradual concentration of production in few clue sectors, "horizontal" structure, incorporation of the enterprises into joint-stock structure, attraction of hired top-managers and transnationaliziation. But against this background the leading Indian business-groups keep main traditional peculiarities: they mostly still belong to the families of their founders, even today they observe caste or communal relations which are the basis of their non-formal backbone tides, they still remain highly diversificated structures with weak interrelations. Specific national ambivalence and combination of traditions and innovations of the leading Indian business-groups provide their high vitality and stability in the controversial, multiform, overloaded with caste and confessional remains Indian reality. We conclude that in contrast to the dominant opinion transformation of these groups into multisectoral corporations of the western type is far from completion, and in the nearest perspective they will still possess all their peculiarities and incident social and economical

  9. The LHC Lead Injector Chain

    CERN Document Server

    Beuret, A; Blas, A; Burkhardt, H; Carli, Christian; Chanel, M; Fowler, A; Gourber-Pace, M; Hancock, S; Hourican, M; Hill, C E; Jowett, John M; Kahle, K; Küchler, D; Lombardi, A M; Mahner, E; Manglunki, Django; Martini, M; Maury, S; Pedersen, F; Raich, U; Rossi, C; Royer, J P; Schindl, Karlheinz; Scrivens, R; Sermeus, L; Shaposhnikova, Elena; Tranquille, G; Vretenar, Maurizio; Zickler, T

    2004-01-01

    A sizeable part of the LHC physics programme foresees lead-lead collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines [1,2]. Each LHC ring will be filled in 10 min by almost 600 bunches, each of 7×107 lead ions. Central to the scheme is the Low Energy Ion Ring (LEIR) [3,4], which transforms long pulses from Linac3 into high-brilliance bunches by means of multi-turn injection, electron cooling and accumulation. Major limitations along the chain, including space charge, intrabeam scattering, vacuum issues and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR involves new magnets and power converters, high-current electron cooling, broadband RF cavities, and a UHV vacuum system with getter (NEG) coatings to achieve a few 10-12 mbar. Major hardware changes in Linac3 and the PS are also covered. An early ion scheme with fewer bunches (but each at nominal...

  10. Lead in Drinking Water in Slovenian Kindergartens and Schools

    Directory of Open Access Journals (Sweden)

    Bitenc K.

    2013-04-01

    Full Text Available The purpose of the work is to determine how high are the concentrations of lead in drinking water in older Slovenian kindergartens and primary schools and to demonstrate that lead can also migrate from newer materials used for the construction of water distribution networks. To determine the concentrations of lead in drinking water, it is needed to take 250 ml of drinking water that stood in the pipes from 8 to 18hours. It is also applied a method for determining the migration from different materials. An old lead pipe is utilized, as well as new materials (PEX-Al-PEX, copper, galvanized pipes and stainless steel pipes. Sampling showed that 6 samples of 39 had levels of lead higher than 10 µg/l, two of them highly exceeded that level. Negative correlation between the level of pH and concentration of lead in drinking water is moderate. Implementation of lead migration from various types of pipes demonstrated the migration from galvanized pipes in all simulants. Furthermore, the migration of lead from galvanized pipes is dependent on water temperature. The migration was confirmed from the lead pipe as expected. Study points to a problem with elevated concentrations of lead in drinking water faced by older kindergartens and primary schools in Slovenia. All concentrations of lead after flushing the pipes were below the 10 µg/l, which shows that the most effective action to lower the concentrations of lead is flushing the water pipes. For the purposes of national monitoring of drinking water is necessary to apply a better method for determining lead levels in drinking water namely the sampling of water that stood in the pipes at least 8 to 18 hours. This study has demonstrated the migration of lead from galvanized pipes. This material is also installed in 54 % of kindergartens and primary schools that participated in the study.

  11. Bromine pretreated chitosan for adsorption of lead (II) from water

    Indian Academy of Sciences (India)

    Pollution by heavy metals like lead (II) is responsible for health hazards and environmental degradation. Adsorption is a prevalent method applied for removal of heavy metal pollutants from water. This study explored adsorption performances of 30% bromine pretreated chitosan for lead (II) abatement from water. Bromine ...

  12. Bromine pretreated chitosan for adsorption of lead (II) from water

    Indian Academy of Sciences (India)

    Abstract. Pollution by heavy metals like lead (II) is responsible for health hazards and environmental degradation. Adsorption is a prevalent method applied for removal of heavy metal pollutants from water. This study explored adsorption performances of 30% bromine pretreated chitosan for lead (II) abatement from water.

  13. Square wave voltammetric determination of lead in commercial kohl ...

    African Journals Online (AJOL)

    A simple sensitive square wave voltammetric method for the determination of lead contamination of several kohl samples purchased from Algeria retail stores was developed using glassy carbon electrode. The peak current response of 5 standards aqueous solution of lead in NaNO3 as supporting electrolyte was observed ...

  14. All roads lead to Rome

    DEFF Research Database (Denmark)

    Ottosen, Thorsten Jørgen; Vomlel, Jiri

    2012-01-01

    size triangulations. The search methods are made faster by efficient dynamic maintenance of the cliques of a graph. This problem was investigated by Stix, and in this paper we derive a new simple method based on the Bron-Kerbosch algorithm that compares favourably to Stix’ approach. The new approach...

  15. Standards for compatibility of printed circuit and component lead materials

    Science.gov (United States)

    1968-01-01

    Study of packaging of microminiature electronic components reveals methods of improving compatibility of lead materials, joining techniques, transfer molding concepts, printed circuit board materials, and process and material specifications.

  16. Memory Functions in Recreational Pistol Sport Shooters: Does Lead Matter?

    National Research Council Canada - National Science Library

    Sanna Asa-Mäkitaipale; Mervi Jehkonen; Jukka Uitti; Juhani Vilkki

    2009-01-01

    ...: The aim of our study was to examine the memory functions of pistol sport shooters using powder charges when exposure to lead is expected to be considerably lower than in occupational circumstances.Methods...

  17. Superconducting properties of lithographic lead break junctions

    Science.gov (United States)

    Weber, David; Scheer, Elke

    2018-01-01

    We have fabricated mechanically controlled break junction samples made of lead (Pb) by means of state-of-the-art nanofabrication methods: electron beam lithography and physical vapour deposition. The electrical and magnetic properties were characterized in a {}3{He} cryostat and showed a hard superconducting gap. Temperature and magnetic field dependence of tunnel contacts were compared and quantitatively described by including either thermal broadening of the density of states or pair breaking in the framework of a Skalski model, respectively. We show point contact spectra of few-atom contacts and present tunneling spectra exhibiting a superconducting double-gap structure.

  18. Electronic and optical properties of lead iodide

    DEFF Research Database (Denmark)

    Ahuja, R.; Arwin, H.; Ferreira da Silva, A.

    2002-01-01

    The electronic properties and the optical absorption of lead iodide (PbI2) have been investigated experimentally by means of optical absorption and spectroscopic ellipsometry, and theoretically by a full-potential linear muffin-tin-orbital method. PbI2 has been recognized as a very promising...... detector material with a large technological applicability. Its band-gap energy as a function of temperature has also been measured by optical absorption. The temperature dependence has been fitted by two different relations, and a discussion of these fittings is given. ©2002 American Institute of Physics....

  19. Testing for lead in toys at day care centers.

    Science.gov (United States)

    Sanders, Martha; Stolz, Julie; Chacon-Baker, Ashley

    2013-01-01

    Exposure to lead-based paint or material has been found to impact children's cognitive and behavioral development at blood lead levels far below current standards. The purpose of the project was to screen for lead in toy items in daycare centers in order to raise awareness of inside environmental lead exposures and minimize lead-based exposures for children. Occupational therapy students in a service learning class tested for lead in ten daycare or public centers using the XRF Thermo Scientific Niton XL3t, a method accepted by the Consumer Product Safety Commission (CPSC). A total of 460 items were tested over a two-month period for an average of 66 toys per setting. Fifty six (56) items tested > 100 ppm, which represented 12% of the entire sample. Items with high lead levels included selected toys constructed with lead-based paint, lead metals, plastics using lead as a color enhancer, and decorative objects. While the actual number of lead-based products is small, the cumulative exposure or habitual use may pose an unnecessary risk to children. Indoor exposures occurred for all day care centers regardless of socio-economic levels. Recommendations to minimize exposures are provided.

  20. Removal of lead contaminated dusts from hard surfaces.

    Science.gov (United States)

    Lewis, Roger D; Condoor, Sridhar; Batek, Joe; Ong, Kee Hean; Backer, Denis; Sterling, David; Siria, Jeff; Chen, John J; Ashley, Peter

    2006-01-15

    Government guidelines have widely recommended trisodium phosphate (TSP) or "lead-specific" cleaning detergents for removal of lead-contaminated dust (LCD) from hard surfaces, such as floors and window areas. The purpose of this study was to determine if low-phosphate, non-lead-specific cleaners could be used to efficiently remove LCD from 3 types of surfaces (vinyl flooring, wood, and wallpaper). Laboratory methods were developed and validated for simulating the doping, embedding, and sponge cleaning of the 3 surface types with 4 categories of cleaners: lead-specific detergents, nonionic cleaners, anionic cleaners, and trisodium phosphate (TSP). Vinyl flooring and wood were worn using artificial means. Materials were ashed, followed by ultrasound extraction, and anodic stripping voltammetry (ASV). One-way analysis of variance approach was used to evaluate the surface and detergent effects. Surface type was found to be a significant factor in removal of lead (p < 0.001). Vinyl flooring cleaned better than wallpaper by over 14% and wood cleaned better than wallpaper by 13%. There was no difference between the cleaning action of vinyl flooring and wood. No evidence was found to support the use of TSP or lead-specific detergents over all-purpose cleaning detergents for removal of lead-contaminated dusts. No-phosphate, non-lead-specific detergents are effective in sponge cleaning of lead-contaminated hard surfaces and childhood lead prevention programs should consider recommending all-purpose household detergents for removal of lead-contaminated dust after appropriate vacuuming.

  1. Blood Lead Levels and Risk Factors among Preschool Children in a Lead Polluted Area in Taizhou, China

    Directory of Open Access Journals (Sweden)

    Zhenyan Gao

    2017-01-01

    Full Text Available Objective. To determine the blood lead levels and identify related risk factors among preschool children in a lead polluted area (Taizhou, China and provide theoretical support for prevention of lead pollution. Methods. A stratified-clustered-random sampling method was used to determine the survey sample. Blood lead levels were determined by the tungsten atomizer absorption spectrophotometer. Results. A total of 2,018 subjects (average age of 59 months; 1,087 boys and 931 girls were included. The arithmetic mean, geometric mean, and median blood lead levels of the preschool children were 56.4 μg/L, 48.9 μg/L, and 46 μg/L. A total of 8.8% children had blood lead levels >100 μg/L and 43.9% had blood lead levels >50 μg/L. Mother’s education level, father’s occupation, decorative tableware, exposure to makeup, and the residential floor were all risk factors for elevated blood lead levels (odds ratios of 1.42, 1.21, 1.11, 1.19, and 1.27, resp., while hand washing before eating food was a protective factor (odds ratio of 0.88. Conclusions. The blood lead levels of preschool children in Taizhou were higher than in other areas in China and in developed countries. Therefore, policies ensuring lead-based industries are not placed in close proximity to residential areas are required.

  2. Relational Leading and Dialogic Process

    DEFF Research Database (Denmark)

    Hansen, Lone Hersted

    The Ph.D. thesis contributes to a relational orientation to leading, emphasizing leadership as a shared, collaborative and co-creative activity. In this paradigm major emphasis is put on dialogue and interaction. Inspired by social constructionist ideas, the thesis considers approaches to learning...... with the thesis, dialogically based practices inspired by action research with the aim to enhance collaborative knowledge building, reflexivity and dialogical skills in groups and teams were carried out, analyzed and documented. Participants included school principals, leaders of kindergartens, teachers...

  3. Lead-nickel electrochemical batteries

    CERN Document Server

    Glaize, Christian

    2012-01-01

    The lead-acid accumulator was introduced in the middle of the 19th Century, the diverse variants of nickel accumulators between the beginning and the end of the 20th Century. Although old, these technologies are always very present on numerous markets. Unfortunately they are still not used in optimal conditions, often because of the misunderstanding of the internal electrochemical phenomena.This book will show that batteries are complex systems, made commercially available thanks to considerable amounts of scientific research, empiricism and practical knowledge. However, the design of

  4. A Comparative Analysis of PID, Lead, Lag, Lead-Lag, and Cascaded Lead Controllers for a Drug Infusion System

    Directory of Open Access Journals (Sweden)

    Zuwwar Khan Jadoon

    2017-01-01

    Full Text Available Goal. The aim of this paper is to conduct a comprehensive comparative analysis between five different controllers for a drug infusion system in total intravenous anesthesia (TIVA administration. Methods. The proposed method models a dilution chamber with first order exponential decay characteristics to represent the pharmacokinetic decay of a drug. The dilution chamber is integrated with five different control techniques with a simulation-based comparative analysis performed between them. The design process is conducted using MATLAB SISOTOOL. Results. The findings show that each controller has its own merits and demerits. The results generated using MATLAB signify and confirm the effectiveness of PI and cascaded lead controllers, with cascaded lead controller as the best control technique to automate and control the propofol delivery. Conclusion. In this paper, different control techniques for measurement-based feedback-controlled propofol delivery is confirmed with promising results. Significance. The comparative analysis showed that this drug infusion platform, merged with the proper control technique, will perform eminently in the field of total intravenous anesthesia.

  5. Do protective lead garments harbor harmful bacteria?

    Science.gov (United States)

    Grogan, Brian F; Cranston, William C; Lopez, Donna M; Furbee, Christopher; Murray, Clinton K; Hsu, Joseph R

    2011-11-09

    This study attempted to identify and characterize bacteria present on shared-use protective lead shielding garments worn in the operating room. Those worn at the authors' institution were collected and swabbed in designated 5×5-cm areas. Swabs were sent to the clinical laboratory for bacterial isolation and identification. All isolates were identified using standard microbiological methods. Isolates then underwent antimicrobial susceptibility testing as per standard hospital procedures. Of 182 total collected swabs, bacteria were isolated on only 5 (2.7%) samples. Coagulase-negative Staphylococci was identified on 3 samples and the remaining 2 grew coagulase-negative Staphylococci and gram-positive rods. The collection sites for these isolates were the lead apron, midline, bottom outer surface (n=3), thyroid shield midline, inner surface (n=1), and skirt midline, bottom inner surface (n=1). Of the collected samples, 98.3% were negative for bacterial growth. The remaining isolates were consistent with common skin flora. No multi-drug resistant organisms were identified on any garments. Standard cleaning procedures at the institution are an effective way to prevent growth of bacteria on shared-use protective lead shielding garments worn in the operating room. Copyright 2011, SLACK Incorporated.

  6. The prospects for Recycling lead-acid batteries in India

    Science.gov (United States)

    Venkateswaran, K. V.; Prabhakar Rethinaraj, J.; Visvanathan, S.

    1990-10-01

    In view of dwindling resources of primary metal and growing environmental awareness, the recycle of lead is becoming increasingly necessary in India and other countries. A perusal of supply and demand projections for India reveals a lead supply shortfall of 68,300 tonnes by the year 2000. With a stagnation of primary metal production, the lead resources contained within spent batteries provide an excellent opportunity for the secondary recovery industry. This article cites various processes used in India to recover lead from spent batteries. In addition, a modified electrochemical method which is currently being adopted is described.

  7. Density Estimation and Anomaly Detection in Large Social Networks

    Science.gov (United States)

    2014-07-15

    compute a subgradient of `t or ft at any point θ ∈ Θ, which we denote ∇`t and ∇ft. Thus the Forecaster incurs the loss `t(θ̂t) = ft(θ̂t) + r(θ̂t). The... subgradient of `t at θ, D(θ‖θ̂t) is the Bregman divergence [12, 15] between θ and θ̂, and ηt > 0 is a step size parameter. Let ψ : Θ → R denote a continuously...Teboulle. Mirror descent and nonlinear projected subgradient methods for convex programming. Operations Research Letters, 31:167–175, 2003. [9] M

  8. Elevation leads to altruistic behavior.

    Science.gov (United States)

    Schnall, Simone; Roper, Jean; Fessler, Daniel M T

    2010-03-01

    Feelings of elevation, elicited by witnessing another person perform a good deed, have been hypothesized to motivate a desire to help others. However, despite growing interest in the determinants of prosocial behavior, there is only limited evidence that elevation leads to increases in altruistic behavior. In two experiments, we tested the relationship between elevation and helping behavior. Prior to measuring helping behavior, we measured elevation among participants in an elevation-inducing condition and control conditions in order to determine whether witnessing altruistic behavior elicited elevation. In Experiment 1, participants experiencing elevation were more likely to volunteer for a subsequent unpaid study than were participants in a neutral state. In Experiment 2, participants experiencing elevation spent approximately twice as long helping the experimenter with a tedious task as participants experiencing mirth or a neutral emotional state. Further, feelings of elevation, but not feelings of amusement or happiness, predicted the amount of helping. Together, these results provide evidence that witnessing another person's altruistic behavior elicits elevation, a discrete emotion that, in turn, leads to tangible increases in altruism.

  9. All roads lead to Meyrin

    CERN Multimedia

    Communication locale

    2011-01-01

    Tous les chemins mènent à Meyrin - All roads lead to Meyrin From 29 September to 16 October, 2011, come to the Salle Antoine Verchère in Meyrin for Tous les chemins mènent à Meyrin. The celebration will include an exposition as well as a theatrical performance about Meyrin, the first satellite city in Switzerland. With the help of the memories and testimonies from the people of Meyrin, Tous les chemins mènent à Meyrin is putting the collective memories of the commune on display. It is an occasion for everyone, whether you're from near or far, to find out how all the roads lead to Meyrin.  Salle Antoine-Verchère Route de Meyrin 294 – 1217 Meyrin Tram 18 – Stop: Meyrin Village Thursdays / Fridays / Saturdays at 8pm Sundays at 5pm Regular ticket: CHF 15.- Concession ticket (students, chômeurs, AVS, AI): CHF 12.- Children up to 16: CHF 10.- Family ticket: CHF 35.-

  10. Neuroprotective effect of wormwood against lead exposure

    Directory of Open Access Journals (Sweden)

    Kharoubi O

    2011-01-01

    Full Text Available Background : Lead poisoning is a potential factor in brain damage, neurochemical dysfunction and severe behavioral problems. Considering this effect, our study was carried out to investigate the effects of wormwood to restore enzymes activities, lipid peroxidation and behavioral changes induced by lead. Methods : Thirty Wistar rats were divided into five groups (n = 6 in each group: three groups exposed to 750 ppm of lead acetate in the drinking water for 11 weeks and two groups as control. Aqueous wormwood extract (200 mg/kg body weight was administrated to intoxicated (Pb(-+A.AB and control groups (A.AB for four supplemental weeks. Activities of acetylcholinesterase (AchE, monoamine oxidase (MAO and thiobarbituric acid-reactive substances (TBARS level were determined in the hypothalamus, hippocampus, cortex and striatum of male rats and the grooming and locomotors activity were defined in all groups. Results: The intoxicated group (Pb has a significantly increased TBARS value compared with the control in all brain regions (P < 0.05 and, after treatment with the wormwood extract, a significant reduction was noted. The enzyme activity decreased significantly (P < 0.05 in the Pb group compared with the control, essentially for the hippocampus (AchE: -57%, MAO: -41% and the striatum (AchE: -43%, MAO: -51%. After wormwood extract administration, the AchE and MAO activity were significantly increased in all brain regions compared with the Pb group (P < 0.05. The behavioral test (locomotors and grooming test indicates a significant hyperactivity in the Pb group compared with the control group. After treatment with wormwood extract, the Pb(-+A.Ab indicates a lower activity compared with Pb. Conclusion : These data suggest that wormwood extract may play a very useful role in reduction of the neurotoxicological damage induced by lead.

  11. Helping Parents Prevent Lead Poisoning. ERIC Digest.

    Science.gov (United States)

    Binns, Helen J.; Ricks, Omar Benton

    Children are at greater risk than adults for lead poisoning because children absorb lead more readily than adults, and a small amount of lead in children's bodies can do a great deal of harm. Some of the causes and effects of childhood lead poisoning and suggests some lead poisoning prevention strategies that parent educators can share with…

  12. Recycling of Exhaust Batteries in Lead-Foam Electrodes

    Science.gov (United States)

    Costanza, Girolamo; Tata, Maria Elisa

    Lead and lead-alloy foams have been investigated in this research. In particular low-cost techniques for the direct production of lead-based electrodes have been analyzed and discussed in this work. The relevance of the main process parameters (powder compacting pressure, granulometry, base metal composition, sintering temperature and time) have been focused and the effect on foam morphology has been discussed too. In particular "Sintering and Dissolution Process" (SDP) and "Replication Process" (RP) have been employed and suitable modified. Both spherical urea and NaCl have been adopted in the SDP method. In the replication process it has been evidenced that the viscosity of the melt is fundamental. Furthermore the research examines lead recovery and recycling of exhaust batteries into foam-based electrodes. A novel method for the direct conversion of Pb scrap into lead foam is discussed too.

  13. Anti-cancer Lead Molecule

    KAUST Repository

    Sagar, Sunil

    2014-04-17

    Derivatives of plumbagin can be selectively cytotoxic to breast cancer cells. Derivative `A` (Acetyl Plumbagin) has emerged as a lead molecule for testing against estrogen positive breast cancer and has shown low hepatotoxicity as well as overall lower toxicity in nude mice model. The toxicity of derivative `A` was determined to be even lower than vehicle control (ALT and AST markers). The possible mechanism of action identified based on the microarray experiments and pathway mapping shows that derivative `A` could be acting by altering the cholesterol-related mechanisms. The low toxicity profile of derivative `A` highlights its possible role as future anti-cancer drug and/or as an adjuvant drug to reduce the toxicity of highly toxic chemotherapeutic drugs

  14. Multi-lead heat sink

    Science.gov (United States)

    Roose, Lars D.

    1984-01-01

    The disclosure relates to a heat sink used to protect integrated circuits from the heat resulting from soldering them to circuit boards. A tubular housing contains a slidable member which engages somewhat inwardly extending connecting rods, each of which is rotatably attached at one end to the bottom of the housing. The other end of each rod is fastened to an expandable coil spring loop. As the member is pushed downward in the housing, its bottom edge engages and forces outward the connecting rods, thereby expanding the spring so that it will fit over an integrated circuit. After the device is in place, the member is slid upward and the spring contracts about the leads of the integrated circuit. Soldering is now conducted and the spring absorbs excess heat therefrom to protect the integrated circuit. The placement steps are repeated in reverse order to remove the heat sink for use again.

  15. Lead-Based Paint and Demolition

    Science.gov (United States)

    The Lead Renovation, Repair, and Painting Rule does not apply to total demolition of a structure. Learn about EPA recommended lead-safe practices during total demolition activities to prevent and minimize exposure to lead.

  16. [XANES study of lead speciation in duckweed].

    Science.gov (United States)

    Chu, Bin-Bin; Luo, Li-Qiang; Xu, Tao; Yuan, Jing; Sun, Jian-Ling; Zeng, Yuan; Ma, Yan-Hong; Yi, Shan

    2012-07-01

    Qixiashan lead-zinc mine of Nanjing was one of the largest lead zinc deposits in East China Its exploitation has been over 50 years, and the environmental pollution has also been increasing. The lead concentration in the local environment was high, but lead migration and toxic mechanism has not been clear. Therefore, biogeochemistry research of the lead zinc mine was carried out. Using ICP-MS and Pb-L III edge XANES, lead concentration and speciation were analyzed respectively, and duckweed which can tolerate and enriched heavy metals was found in the pollution area. The results showed that the lead concentration of duckweed was 39.4 mg x kg(-1). XANES analysis and linear combination fit indicated that lead stearate and lead sulfide accounted for 65% and 36.9% respectively in the lead speciation of duckweed, suggesting that the main lead speciation of duckweed was sulfur-containing lead-organic acid.

  17. Basic Information about Lead in Drinking Water

    Science.gov (United States)

    ... Health) Lead can also be transmitted through breast milk. Read more on lead exposure in pregnancy and lactating women (PDF) (302 pp, 4.3 MB, About PDF ) . Adults Lead is also harmful to adults. Adults exposed ...

  18. Lead content in 70 brands of dietary calcium supplements.

    Science.gov (United States)

    Bourgoin, B P; Evans, D R; Cornett, J R; Lingard, S M; Quattrone, A J

    1993-01-01

    OBJECTIVES. Elevated lead levels in calcium supplements may pose a health risk, particularly to children with milk intolerance who rely on these products to meet their calcium requirement. Earlier reports chiefly focused on the lead content in supplements derived from bonemeal and dolomite. This study undertook to determine the lead levels in the major forms of calcium supplements currently available. METHODS. The lead content was measured in 70 brands of calcium supplements grouped in the following five categories: dolomite, bonemeal, refined and natural source calcium carbonate, and calcium chelates. RESULTS. The lead levels measured in the supplements ranged from 0.03 microgram/g to 8.83 micrograms/g. Daily lead ingestion rates revealed that about 25% of the products exceeded the US Food and Drug Administration's "provisional" total tolerable daily intake of lead for children aged 6 years and under. Less than 20% of the supplements had "normalized" lead levels comparable to or lower than that reported for cow's milk. CONCLUSIONS. Children are the most sensitive to the low-level effects of lead. If calcium supplements are to provide an alternate source of calcium to some of these individuals, they should also deliver concomitant lead dosages no greater than those obtained from milk products themselves. PMID:8342726

  19. E-Waste Informal Recycling: An Emerging Source of Lead Exposure in South America

    OpenAIRE

    Pascale, Antonio; Sosa, Adriana; Bares, Cristina; Battocletti, Alejandra; Moll, María José; Pose, Darío; Laborde, Amalia; González, Hugo; Feola, Gabriella

    2016-01-01

    BACKGROUND Primitive electronic waste (e-waste) recycling creates exposures to several hazardous substances including lead. In Uruguay, primitive recycling procedures are a significant source of lead exposure. OBJECTIVES The aim of this study was to examine lead exposure in blood lead levels (BLLs) in low-income children exposed to lead through burning cables. METHODS A sample of children and adolescents exposed to lead through burning cable activities were assessed at the Department of Toxic...

  20. The identification of lead ammunition as a source of lead exposure in First Nations: The use of lead isotope ratios

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Leonard J.S. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: ljtsuji@fes.uwaterloo.ca; Wainman, Bruce C. [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Martin, Ian D. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Sutherland, Celine [Attawapiskat First Nation Health Services, Attawapiskat, Ontario, P0L 1A0 (Canada); Weber, Jean-Philippe; Dumas, Pierre [Centre de toxicologie, Institut national de sante publique du Quebec, Quebec City, Quebec, G1V 5B3 (Canada); Nieboer, Evert [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Institute of Community Medicine, University of Tromso, Tromso N-9037 (Norway)

    2008-04-15

    The use of lead shotshell to hunt water birds has been associated with lead-contamination in game meat. However, evidence illustrating that lead shotshell is a source of lead exposure in subsistence hunting groups cannot be deemed definitive. This study seeks to determine whether lead shotshell constitutes a source of lead exposure using lead isotope ratios. We examined stable lead isotope ratios for lichens, lead shotshell and bullets, and blood from residents of Fort Albany and Kashechewan First Nations, and the City of Hamilton, Ontario, Canada. Data were analyzed using ANOVA and regression analyses. ANOVA of isotope ratios for blood revealed significant differences with respect to location, but not sex. Hamilton differed from both Kashechewan and Fort Albany; however, the First Nations did not differ from each other. ANOVA of the isotope ratios for lead ammunition and lichens revealed no significant differences between lichen groups (north and south) and for the lead ammunition sources (pellets and bullets). A plot of {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb values illustrated that lichens and lead ammunition were distinct groupings and only the 95% confidence ellipse of the First Nations group overlapped that of lead ammunition. In addition, partial correlations between blood-lead levels (adjusted for age) and isotope ratios revealed significant (p < 0.05) positive correlations for {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb, and a significant negative correlation for {sup 208}Pb/{sup 206}Pb, as predicted if leaded ammunition were the source of lead exposure. In conclusion, lead ammunition was identified as a source of lead exposure for First Nations people; however, the isotope ratios for lead shotshell pellets and bullets were indistinguishable. Thus, lead-contaminated meat from game harvested with lead bullets may also be contributing to the lead body burden.

  1. Association of Lead Levels and Cerebral Palsy

    OpenAIRE

    Neha Bansal MD; Anju Aggarwal MD, FIAP, MNAMS; M. M. A. Faridi MD, FIAP, MNAMS; Tusha Sharma PhD; B. D. Baneerjee PhD

    2017-01-01

    Background: Cerebral palsy is a common motor disability in childhood. Raised lead levels affect cognition. Children with cerebral palsy may have raised lead levels, further impairing their residual cognitive motor and behavioral abilities. Environmental exposure and abnormal eating habits may lead to increased lead levels. Aims and Objectives: To measure blood lead levels in children with cerebral palsy and compare them with healthy neurologically normal children. To correlate blood lead leve...

  2. Evaluation and management of lead exposure

    OpenAIRE

    Kim, Hwan-Cheol; Jang, Tae-Won; Chae, Hong-Jae; Choi, Won-Jun; Ha, Mi-Na; Ye, Byeong-Jin; Kim, Byoung-Gwon; Jeon, Man-Joong; Kim, Se-yeong; Hong, Young-Seoub

    2015-01-01

    Lead, which is widely used in industry, is a common element found in low concentrations in the Earth?s crust. Implementations to reduce environmental lead concentrations have resulted in a considerable reduction of lead levels in the environment (air) and a sustained reduction in the blood lead levels of the average citizen. However, people are still being exposed to lead through a variety of routes in everyday commodities. Lead causes health problems such as toxicity of the liver, kidneys, h...

  3. [Relationship between XRCC3 gene polymorphism and susceptibility to lead poisoning in male lead-exposed workers].

    Science.gov (United States)

    Liu, Xiang-quan; Zhang, Zhong

    2013-06-01

    To investigate the relationship between genetic polymorphism of X-ray repair cross-complementing gene 3 (XRCC3) and susceptibility to lead poisoning in male lead-exposed workers. Peripheral venous blood and morning urine samples were collected from 326 male lead-exposed workers in a storage battery factory in Fuzhou. Blood lead, urine lead, blood zinc protoporphyrin (ZPP), blood calcium, and blood iron were measured. The genotype of XRCC3 was determined by polymerase chain reaction-restriction fragment length polymorphism method. The relationship between XRCC3 gene polymorphism and susceptibility to lead poisoning in male lead-exposed workers was analyzed. Genetic polymorphism of XRCC3 was seen in the 326 subjects. The frequency distribution of XRCC3 genotypes, XRCC3-241CC (wild type), XRCC3-241CT (heterozygous mutation), and XRCC3-241TT (homozygous mutation), was in accordance with the Hardy-Weinberg equilibrium (P > 0.05). There were no significant differences in urine lead, blood ZPP, blood calcium, and blood iron between the lead-exposed workers with different XRCC3 genotypes (P > 0.05). The workers with XRCC3-241CT/TT had a significantly higher mean blood lead level than those with XRCC3-241CC (P lead level of 1.90 µmol/L as the cutoff value, the chi-square test and logistic regression analysis showed that the proportion of workers with XRCC3-241CT/TT was significantly higher than that of workers with XRCC3-241CC in the subjects with high blood leads (P lead was significantly higher in the workers with XRCC3-241CT/TT than in those with XRCC3-241CC (OR = 2.34, 95%CI = 1.61 ∼ 5.13); the multivariate linear regression analysis showed that the workers with XRCC3-241CT/TT had high blood lead levels (β = 0.116, P lead absorption (β = 0.188, P lead absorption (β = -0.247, P lead levels (β = -0.145, P lead at workplace, the workers with XRCC3-241CT/TT have a significantly higher blood lead level than those with XRCC3-241CC, so the genotype of XRCC3-241CT

  4. All Roads Lead To Rome

    DEFF Research Database (Denmark)

    Ottosen, Thorsten Jørgen; Vomlel, Jiri

    2010-01-01

    To perform ecient inference in Bayesian networks, the network graph needs to be triangu- lated. The quality of this triangulation largely determines the efficiency of the subsequent inference, but the triangulation problem is unfortunately NP-hard. It is common for ex- isting methods to use the t...

  5. Lead exposure in Nunavik: from research to action

    Directory of Open Access Journals (Sweden)

    Ariane Couture

    2012-07-01

    Full Text Available Background. In 1999, the Government of Canada regulated the use of lead shot for hunting. Concurrently, the Nunavik Regional Board of Health and Social Services (NRBHSS was informed of the results of an isotope study that pointed to lead ammunition as a likely source of lead exposure in Nunavik. Rapidly thereafter, a coalition for the banning of lead shot was implemented by the NRBHSS as well as by regional/local partners and by Inuit hunters in order to disseminate this information to the public. Objectives. The purpose of this article is to describe the intervention conducted in the winter of 1999 by the NRBHSS and to assess the combined impact of national legislation and an awareness campaign on blood lead levels in Nunavik. Study design. Impact assessment of the intervention for the banning of lead shot conducted in 1999 in Nunavik using blood lead levels data before and after the intervention. Methods. Data on blood lead levels in Nunavik describing foetal exposure as well as during childhood and in adults published between 1992 and 2009 were compiled. Blood lead levels in Nunavik prior to and after the interventions were compared. To assess the current situation, the most recent blood lead levels were compared with those from surveys conducted during the same period in North America. Results. Analysis of blood samples collected from umbilical cord and from adults show that blood lead levels in Nunavik significantly declined between 1992 and 2004. Nevertheless, lead exposure in Nunavik still remains higher in comparison to that observed in other North American surveys. Conclusions. The current situation regarding lead exposure in Nunavik has significantly improved as a result of the implemented intervention. However, according to recent data, a gap still subsists relative to other North American populations.

  6. Do US Ambient Air Lead Levels Have a Significant Impact on Childhood Blood Lead Levels: Results of a National Study

    Directory of Open Access Journals (Sweden)

    LuAnn L. Brink

    2013-01-01

    Full Text Available Introduction. Although lead paint and leaded gasoline have not been used in the US for thirty years, thousands of US children continue to have blood lead levels (BLLs of concern. Methods. We investigated the potential association of modeled air lead levels and BLLs ≥ 10 μg/dL using a large CDC database with BLLs on children aged 0–3 years. Percent of children with BLLs ≥ 10 μg/dL (2000–2007 by county and proportion of pre-50 housing and SES variables were merged with the US EPA's National Air Toxics Assessment (NATA modeled air lead data. Results. The proportion with BLL ≥ 10 μg/dL was 1.24% in the highest air lead counties, and the proportion with BLL ≥ 10 μg/dL was 0.36% in the lowest air lead counties, resulting in a crude prevalence ratio of 3.4. Further analysis using multivariate negative binomial regression revealed that NATA lead was a significant predictor of % BLL ≥ 10 μg/dL after controlling for percent pre-l950 housing, percent rural, and percent black. A geospatial regression revealed that air lead, percent older housing, and poverty were all significant predictors of % BLL ≥ 10 μg/dL. Conclusions. More emphasis should be given to potential sources of ambient air lead near residential areas.

  7. Stable lead isotopes and lake sediments--a useful combination for the study of atmospheric lead pollution history.

    Science.gov (United States)

    Renberg, I; Brännvall, M L; Bindler, R; Emteryd, O

    2002-06-20

    Analysis of stable lead isotopes and lead concentrations in lake-sediment deposits, not least in varved (annually-laminated) sediments, is a useful method to study lead pollution history. This paper presents details from a study of 31 lakes in Sweden. Using a strong acid digestion of sediment samples and ICP-MS analyses, we have found that Swedish lake sediments have a high natural (pre-pollution) 206[Pb]207[Pb] ratio (mean 1.52+/-0.18, range 1.28-2.01, n=31 lakes). In contrast, atmospheric lead pollution derived from metal smelting processes, coal burning and from alkyl-lead added to petrol has a lower ratio (pollution lead deposition began approximately 3500 years ago, the lead isotope ratio of the sediments started to decline, and in modern sediments it is typically pollution and natural lead in sediment samples can be calculated. The pollution lead records of the Swedish lake sediments show a consistent picture of the atmospheric lead pollution history. Some noticeable features are the Roman peak (approx. 0 AD), the large and permanent Medieval increase (approx. 1000 AD), peaks at approximately 1200 and 1530 AD, the rapid increase after World War II, the peak in the 1970s, and the large modern decline.

  8. Darwinian selection leads to Gaia.

    Science.gov (United States)

    Staley, Mark

    2002-09-07

    The Gaia hypothesis, in its strongest form, states that the Earth's atmosphere, oceans, and biota form a tightly coupled system that maintains environmental conditions close to optimal for life. According to Gaia theory, optimal conditions are intrinsic, immutable properties of living organisms. It is assumed that the role of Darwinian selection is to favor organisms that act to stabilize environmental conditions at these optimal levels. In this paper, an alternative form of Gaia theory based on more traditional Darwinian principles is proposed. In the new approach, environmental regulation is a consequence of population dynamics, not Darwinian selection. The role of selection is to favor organisms that are best adapted to prevailing environmental conditions. However, the environment is not a static backdrop for evolution, but is heavily influenced by the presence of living organisms. The resulting co-evolving dynamical process eventually leads to the convergence of equilibrium and optimal conditions. A simple Daisyworld model is used to illustrate this convergence phenomenon. Sensitivity analysis of the Daisyworld model suggests that in stable ecosystems, the convergence of equilibrium and optimal conditions is inevitable, provided there are no externally driven shocks to the system. The end result may appear to be the product of a cooperative venture, but is in fact the outcome of Darwinian selection acting upon "selfish" organisms.

  9. Leading local politicians visit CERN

    CERN Multimedia

    2001-01-01

    Left to right:  Professor Maiani, Ernest Nycollin, Anne-Marie Comparini, and Jean Pépin surrounded by young PRAC. On the 13th of November leading local politicians : Mme Anne-Marie Comparini, Présidente du Conseil régional de Rhône-Alpes, M. Ernest Nycollin, Président du Conseil général de la Haute-Savoie et M. Jean Pépin, Président du Conseil général de l'Ain took part in a ceremony which featured the insertion of one of the first LHC magnets into its cryostat.  The department of l'Ain financed a large part of the contruction of building SMA 18 which will see intense activity during the assembly of LHC magnets over the next four years. The department of Haute-Savoie helped in the development of the ultrasonic welding machine for the superconducting cables and the conception of integrated circuits that will be used to measure temperature and pressure inside the magnets. T...

  10. Evidence of a Lead Metathesis Product from Calcium Hydroxyapatite Dissolution in Lead Nitrate Solution

    Directory of Open Access Journals (Sweden)

    Oratai Saisa-ard

    2014-01-01

    Full Text Available Calcium hydroxyapatite, CaHAp, synthesized by the precipitation method, was utilized to study the calcium-lead metathesis reaction on dissolution in a lead nitrate solution under reflux conditions to prepare larger lead hydroxyapatite, PbHAp, crystals from CaHAp. SEM images show development of crystalline PbHAp on the surfaces of CaHAp. The needle-like crystal morphology observed for PbHAp after 24 h reaction time developed into hexagonal-rod crystal morphology within 48 h reaction time. The largest PbHAp crystals obtained from 48 h reaction time have approximate size of 10 × 10 × 40 μm. Powder X-ray diffraction results show mixed phases of CaHAp and PbHAp due to difficulty in separating the PbHAp product from the CaHAp substrate. The PbHAp peaks observed after 24 h of reaction sharpen and increase in intensity after 48 h of reaction confirming that the PbHAp phase is the major product for the 48 h reaction time. EDX results of the crystalline products show high intensity Pb peaks with lead to phosphorous ratio (5 : 3 as expected for PbHAp. Lower intensity Ca peaks are also observed, consistent with incomplete coverage of the CaHAp growth substrate.

  11. Determination of Lead in Urine by Atomic Absorption Spectrophotometry1

    Science.gov (United States)

    Selander, Stig; Cramé, Kim

    1968-01-01

    A method for the determination of lead in urine by means of atomic absorption spectrophotometry (AAS) is described. A combination of wet ashing and extraction with ammonium pyrrolidine dithiocarbamate into isobutylmethylketone was used. The sensitivity was about 0·02 μg./ml. for 1% absorption, and the detection limit was about 0·02 μg./ml. with an instrumental setting convenient for routine analyses of urines. Using the scale expansion technique, the detection limit was below 0·01 μg./ml., but it was found easier to determine urinary lead concentrations below 0·05 μg./ml. by concentrating the lead in the organic solvent by increasing the volume of urine or decreasing that of the solvent. The method was applied to fresh urines, stored urines, and to urines, obtained during treatment with chelating agents, of patients with lead poisoning. Urines with added inorganic lead were not used. The results agreed well with those obtained with a colorimetric dithizone extraction method (r = 0·989). The AAS method is somewhat more simple and allows the determination of smaller lead concentrations. PMID:5647975

  12. Determination of copper, lead and zinc in fruit preserves

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, N.K.H.; Kolesnichenko, A.I.; Kesel' brener, E.I.

    Copper, lead and zinc content in canned fruit manufactured in Moldavia in 1979 and 1980 was determined by polarography and atomic-absorption spectrophotometry. The authors developed a method for determining the above trace elements in one sample using an atomic-absorption spectrophotometer. The errors of each method were calculated. It was ascertained that the data obtained by both the methods were identical. Analysis of the data indicates that the content of copper, lead and zinc is within the standards approved by the USSR Ministry of Health. The data obtained in the studies can be used in both toxicological work on setting standards of heavy metals content in canned food and in the tables of the chemical composition of canned food. The methods for copper, lead and zinc determination can be used as the basis for the development of standard procedures for heavy metals.

  13. Lead exposure biomarkers and mini-mental status exam scores in older men

    NARCIS (Netherlands)

    Wright, RO; Tsaih, SW; Schwartz, J; Spiro, A; McDonald, K; Weiss, ST; Hu, H

    2003-01-01

    Background: Lead is neurotoxic; yet, whether cognitive decline in older persons is associated with lead exposure is unknown. We studied whether lead exposure biomarkers are associated with cognitive test scores, as well as the modifying effects of age on the lead-cognition relationship. Methods:

  14. Childhood Lead Exposure from Battery Recycling in Vietnam

    Directory of Open Access Journals (Sweden)

    William E. Daniell

    2015-01-01

    Full Text Available Background. Battery recycling facilities in developing countries can cause community lead exposure. Objective. To evaluate child lead exposure in a Vietnam battery recycling craft village after efforts to shift home-based recycling outside the village. Methods. This cross-sectional study evaluated 109 children in Dong Mai village, using blood lead level (BLL measurement, parent interview, and household observation. Blood samples were analyzed with a LeadCare II field instrument; highest BLLs (≥45 μg/dL were retested by laboratory analysis. Surface and soil lead were measured at 11 households and a school with X-ray fluorescence analyzer. Results. All children had high BLLs; 28% had BLL ≥45 μg/dL. Younger age, family recycling, and outside brick surfaces were associated with higher BLL. Surface and soil lead levels were high at all tested homes, even with no recycling history. Laboratory BLLs were lower than LeadCare BLLs, in 24 retested children. Discussion. In spite of improvements, lead exposure was still substantial and probably associated with continued home-based recycling, legacy contamination, and workplace take-home exposure pathways. There is a need for effective strategies to manage lead exposure from battery recycling in craft villages. These reported BLL values should be interpreted cautiously, although the observed field-laboratory discordance may reflect bias in laboratory results.

  15. Dietary exposure to lead in the Netherlands

    NARCIS (Netherlands)

    Boon PE; te Biesebeek JD; van Donkersgoed G; VVH; V&Z

    2017-01-01

    Uptake from the soil is the main route by which lead ends up in food. Lead in soil has its origin in both natural and anthropogenic sources. The lead concentration in food has decreased over the last decennia by the use of unleaded petrol and paint, and the replacement of lead water pipes.

  16. Lead Poisoning: A Need for Education.

    Science.gov (United States)

    Lipnickey, Susan Cross

    1981-01-01

    Each year approximately 200 children die of lead poisoning. Especially vulnerable to the toxic effects of lead poisoning are the nervous system, kidneys, and the bones. Physiological effects of lead on the school-age child, screening processes, and roles of school personnel in dealing with suspected victims of lead poisoning are discussed. (JN)

  17. Leading a Culture of Fitness

    Science.gov (United States)

    2011-03-24

    exhaustion with the body‘s ability to consume oxygen ( VO2max - volume per time, oxygen, maximum). 40 By doing this, he proved the body‘s ability to...Program. As shown earlier, VO2max is a good indicator of cardio respiratory fitness. A maximum effort test on a treadmill is one of the most...accepted and accurate methods to determine VO2max , but the test is lengthy, complicated, and comes with risks. To avoid these drawbacks, the Air Force 9

  18. Peripheral Blood Signatures of Lead Exposure

    Science.gov (United States)

    LaBreche, Heather G.; Meadows, Sarah K.; Nevins, Joseph R.; Chute, John P.

    2011-01-01

    Background Current evidence indicates that even low-level lead (Pb) exposure can have detrimental effects, especially in children. We tested the hypothesis that Pb exposure alters gene expression patterns in peripheral blood cells and that these changes reflect dose-specific alterations in the activity of particular pathways. Methodology/Principal Finding Using Affymetrix Mouse Genome 430 2.0 arrays, we examined gene expression changes in the peripheral blood of female Balb/c mice following exposure to per os lead acetate trihydrate or plain drinking water for two weeks and after a two-week recovery period. Data sets were RMA-normalized and dose-specific signatures were generated using established methods of supervised classification and binary regression. Pathway activity was analyzed using the ScoreSignatures module from GenePattern. Conclusions/Significance The low-level Pb signature was 93% sensitive and 100% specific in classifying samples a leave-one-out crossvalidation. The high-level Pb signature demonstrated 100% sensitivity and specificity in the leave-one-out crossvalidation. These two signatures exhibited dose-specificity in their ability to predict Pb exposure and had little overlap in terms of constituent genes. The signatures also seemed to reflect current levels of Pb exposure rather than past exposure. Finally, the two doses showed differential activation of cellular pathways. Low-level Pb exposure increased activity of the interferon-gamma pathway, whereas high-level Pb exposure increased activity of the E2F1 pathway. PMID:21829687

  19. Long-term reliability of sweet-tip type screw-in leads.

    Science.gov (United States)

    Takano, Asuka; Sekita, Gaku; Watanabe, Minako; Mukaida, Hiroshi; Komatsu, Sayaka; Tabuchi, Haruna; Hayashi, Hidemori; Tokano, Takashi; Sumiyoshi, Masataka; Nakazato, Yuji; Daida, Hiroyuki

    2017-02-01

    Active fixation leads have provided stable atrial and ventricular pacing; however, long-term follow-up data have not been satisfactory. The purpose of this study was to investigate the long-term reliability of active fixation leads and their electrical characteristic stability. A total of 1196 pacing leads were implanted in 830 patients consecutively between 2002 and 2013. In this retrospective study, we were able to trace 1092 leads in 750 patients to investigate the prognosis of implanted leads. The measurement values (including pacing thresholds, sensing amplitudes, and lead impedances of both the atrial and ventricular leads) were obtained from medical records at the time of implantation and during follow up at the outpatient device clinic. All pacing leads were FINELINE II Sterox EZ Leads (Boston Scientific, MN, USA), which are sweet-tip type screw-in active fixation leads, except for the shock leads in patients with implantable cardioverter defibrillator. The mean follow-up period was 51.3±29.2 months (median, 48 months). A total of 1092 leads were implanted in either the atrium (682 leads) or the ventricle (410 leads). Venous access was achieved through cephalic vein cut down (CVC) method (914 leads) or the subclavian vein puncture (SVP) method (178 leads). The overall lead survival rate was 99.6% at both 5 and 10 years. Lead fracture was observed in 4 of 1092 leads (0.37%), all of which were implanted by the SVP method. No lead fracture occurred among patients wherein CVC method was applied (pleads were satisfactory throughout the long-term follow-up period (median, 4 years). Because it was associated with less lead fractures, cut-down access from the cephalic vein may be recommended as the first-line approach when considering the importance of long-term durability of pacing leads.

  20. Lead Tolerance and Accumulation in White Poplar Cultivated In Vitro

    Directory of Open Access Journals (Sweden)

    Branislav Kovačević

    2013-06-01

    Full Text Available Background and Purpose: This paper analyses the lead tolerance and accumulation in white poplar genotypes in vitro, in order to optimize genotype evaluation and other procedures in their implementation in phytoremediation projects and landscaping in areas endangered by lead accumulation. Material and Methods: The lead tolerance and accumulation of five white poplar genotypes after 35 days in vitro cultivation on media supplemented with lead was examined. The following Pb(NO32 concentrations were used: 0, 10-6, 10-5, 10-4 and 10-3 M. Tolerance analysis (described by tolerance indices was based on morphological parameters, biomass accumulation and the content of photosynthetic pigments, while lead accumulation was described by shoot lead accumulation and shoot lead content. Results and Conclusions: The chosen lead concentrations appeared not to be lethal. Moreover, the obtained results showed that the tested lead concentrations had a positive effect on: number of formed roots, shoot moisture content and shoot height. The best differentiation among the examined genotypes was gained by the tolerance index based on the shoot height on 10-4 M Pb(NO32. The shoot lead accumulation and shoot lead content significantly increased on 10-4 and 10-3 M Pb(NO32 media. Thus, the concentration of 10-4 M Pb(NO32 is recommended for further research. Two examined genotypes of horticultural value (LCM and LBM achieved a significantly higher lead shoot content compared to the wide spread genotype “Villafranca” (almost 200% and 125% higher, respectively.

  1. Lead in game birds in Denmark - levels and sources

    DEFF Research Database (Denmark)

    Kanstrup, Niels

    2012-01-01

    ). The study was carried out from August 2008 to April 2009, and followed up in April 2010 and October 2011. The study was based on sampling of a control group of 30 pheasants (Phasianus colchicus) on six private estates which had shown elevated lead levels in 2007. For this group, the local employees were...... instructed to be careful to ensure that the samples were obtained either with steel (non-lead) shot or without the use of firearms. However, at one estate the sample (N=5) was taken with bismuth shot. The lead levels of the control group were measured using the same methodology as the standard measurement...... and independent factors indicate that the lead in the meat samples first and foremost originates from shot and fragments of shot situated in the breast muscles of the bird, and thus contaminating the sample for lead measurement. The contamination is accelerated by the method used for preparation of the sample...

  2. The acute toxicity of lead nitrate on Daphnia magna Straus ...

    African Journals Online (AJOL)

    In this study the acute toxicity of lead nitrate (Pb(NO3)2) to Daphnia magna Straus was investigated in a static bioassay. After 24 h the mobility of daphnids were examined and immobile ones were counted. The 24 h EC50 of lead nitrate to D. magna was found as 0.44 mg/L. According to Behrens-Karber method the 24 h ...

  3. Lead Your Boss The Subtle Art of Managing Up

    CERN Document Server

    Baldoni, John

    2009-01-01

    Every manager on the move wants to have influence at the top in order to get his or her ideas heard and ultimately acted upon. In Lead Your Boss, recognized leadership guru John Baldoni gives managers new—as well as tried-and-true— methods for influencing both their bosses and their peers, and giving senior leaders reasons to follow their lead. Featuring instructive stories based on real-life experiences from leaders at all levels, Lead Your Boss reveals proven strategies for: • Developing spheres of influence • Handling tough issues • Asserting oneself diplomatically • Putting the team first

  4. Lead Apron Inspection Using Infrared Light: A Model Validation Study.

    Science.gov (United States)

    McKenney, Sarah E; Otero, Hansel J; Fricke, Stanley T

    2017-11-08

    To evaluate defect detection in radiation protective apparel, typically called lead aprons, using infrared (IR) thermal imaging. The use of IR lighting eliminates the need for access to x-ray-emitting equipment and radiation dose to the inspector. The performance of radiation workers was prospectively assessed using both a tactile inspection and the IR inspection with a lead apron phantom over a 2-month period. The phantom was a modified lead apron with a series of nine holes of increasing diameter ranging from 2 to 35 mm in accordance with typical rejection criteria. Using the tactile method, a radiation worker would feel for the defects in the lead apron. For the IR inspection, a 250-W IR light source was used to illuminate the lead apron phantom; an IR camera detected the transmitted radiation. The radiation workers evaluated two stills from the IR camera. From the 31 participants inspecting the lead apron phantom with the tactile method, only 2 participants (6%) correctly discovered all 9 holes and 1 participant reported a defect that was not there; 10 of the 20 participants (50%) correctly identified all 9 holes using the IR method. Using a weighted average, 5.4 defects were detected with the tactile method and 7.5 defects were detected with the IR method. IR light can penetrate an apron's protective outer fabric and illuminate defects below the current standard rejection size criteria. The IR method improves defect detectability as compared with the tactile method. Copyright © 2017 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  5. Lead poisoning in captive wild animals

    Energy Technology Data Exchange (ETDEWEB)

    Zook, B.C.; Sauer, R.M.; Garner, F.M.

    1972-07-01

    Lead poisoning was diagnosed post-mortem in 34 simian primates, 11 parrots, and 3 Australian fruit bats at the National Zoological Park. Diagnoses were made by the finding of acid-fast intranuclear inclusion bodies in renal epithelia or hepatocytes and, in most cases, by finding excess lead in samples of liver. The estimated prevalence of lead intoxication among autopsied primates and parrots was 44% and 50% respectively. Leaded paint was found in many animal enclosures at this zoo and it was available to all the lead-poisoned animals in this study. The finding of renal intranuclear inclusion bodies in animals at several zoos, scattered reports of lead intoxication of animals dwelling in various zoos, the occurrence of leaded paint in many zoos and the high incidence of lead poisoning at this zoo, indicated that lead poisoning of zoo animals is much more common than was previously thought.

  6. Blood lead and zinc protoporphyrin levels in donkeys and mules near a secondary lead smelter in Jamaica, 1987-88

    Energy Technology Data Exchange (ETDEWEB)

    Ostrowski, S.R.; Gunter, E.W.; Matte, T.D. (Centers for Disease Control, Atlanta, GA (USA))

    1990-02-01

    During the course of an investigation into community lead poisoning near a secondary lead smelter in Jamaica, blood lead and zinc protoporphyrin levels were measured in 8 exposed and 6 (3 Jamaican, 3 US) unexposed donkeys and mules. The blood lead levels of 6 animals in the contaminated area ranged from 7.5 to 33 micrograms/dl (mean = 17.6 micrograms/dl), compared to 1.8 and 2.4 in unexposed Jamaican animals. More striking was the difference in zinc protoporphyrin levels; all 8 exposed donkeys and mules had values between 900 and 1890 micrograms/dl, compared with a range of 34-46 micrograms/dl for 3 Jamaican control donkeys. These findings suggest that zinc protoporphyrin may be a useful method of screening for subclinical lead toxicity in equines.

  7. Leading gravitational corrections and a unified universe

    DEFF Research Database (Denmark)

    Codello, Alessandro; Jain, Rajeev Kumar

    2016-01-01

    Leading order gravitational corrections to the Einstein-Hilbert action can lead to a consistent picture of the universe by unifying the epochs of inflation and dark energy in a single framework. While the leading local correction induces an inflationary phase in the early universe, the leading...... nonlocal term leads to an accelerated expansion of the universe at the present epoch. We argue that both the leading UV and IR terms can be obtained within the framework of a covariant effective field theory of gravity. The perturbative gravitational corrections therefore provide a fundamental basis...

  8. Lead poisoning in children: a case report.

    Science.gov (United States)

    Jouhadi, Zineb; Bensabbahia, Dalal; Chafiq, Fouad; Oukkache, Bouchra; Guebessi, Nisrine Bennani; Abdellah, El Abidi; Najib, Jilali

    2016-01-01

    Lead colic is a rare cause of abdominal pain. The diagnosis of lead poisoning is most often mentioned in at risk populations (children, psychotic). We report the case of a 2 year old child that was presented for acute abdomen. Abdominal plain radiograph showed multiple intra-colonic metallic particles and suggested lead poisoning diagnosis. Anamnesis found a notion of pica and consumption of peeling paint. Elevated blood lead levels (BLL) confirmed the diagnosis. The lead poisoning is a public health problem especially in children, but its manifestation by a lead colic is rare and could simulate an acute abdomen table.

  9. Evaluating Oral Fluid as a Screening Tool for Lead Poisoning.

    Science.gov (United States)

    Gardner, Sher Lynn; Geller, Robert J; Hannigan, Robyn; Sun, Yu; Mangla, Anil

    2016-11-01

    Screening for lead poisoning is necessary in young children, but obtaining the needed blood sample is unpleasant and sometimes very difficult. Use of an alternative screening method that is less unpleasant and less difficult would likely help to increase the percent of children receiving screening. To evaluate the correlation of oral fluid and blood lead in a clinical setting, and to ascertain the acceptability and feasibility of obtaining oral fluid from a young child in the clinical setting. Oral fluid samples were collected from a convenience sample of 431 children aged 6 months to 5 years already due to receive a blood lead test in a primary care clinic. Blood lead results obtained at the same time were available for 407 children. The results of the two tests were compared with the blood lead test considered to be the "gold standard". Data analysis used Pearson correlations, scatter plots, linear regression, ANOVA and Bland-Altman analysis. 431 patients had oral fluid samples available for analysis, and 407 patients had blood samples available. Patients who had both blood concentrations lead values less than the value recommended for further intervention occurred in 176; no patients had elevated blood lead values with below-intervention oral fluid values. The negative predictive value of an oral fluid lead below the screening cutoff value was 100%. The use of oral fluid to screen for elevated body burdens of lead instead of the usual blood lead sample is feasible with a negative predictive value of 100%, while eliminating the need for blood for lead screening in more than half of these children. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Urban Youth Knowledge and Attitudes Regarding Lead Poisoning.

    Science.gov (United States)

    Bogar, Sandra; Szabo, Aniko; Woodruff, Shane; Johnson, Sheri

    2017-12-01

    Environmental health literacy (EHL) is a promising and evolving field of research that could benefit from youth engagement. Yet studies focused on youths' environmental health awareness and concerns are limited. For example, although lead exposure remains a threat to youth development in urban environments, no published studies have measured urban youth's knowledge of lead poisoning. A CBPR partnership established a youth advisory council (YAC) who helped to design, interpret and disseminate a mixed methods study exploring environmental health perceptions among urban youths ages 10-18. Surveys assessed awareness, attitudes, and knowledge regarding lead poisoning and five environmental health issues determined by the YAC. Focus group questions further contextualized youths' lead knowledge and understanding of youths' environmental health concerns. A majority of youth could identify specific sources of lead exposure but had minimal knowledge of prevention strategies, and focus group data revealed misinformation regarding lead sources and consequences. Survey and focus group respondents' level of awareness and concern regarding YAC-selected EH issues was high in comparison to lead poisoning. In particular, job opportunities and police brutality were endorsed as both neighborhood concerns and priorities. Awareness and knowledge of environmental health issues among urban youth have not been well described. These findings reinforce the importance of addressing problems of local relevance. Moving forward, lead poisoning prevention education for youth and youth EHL partnerships may benefit from incorporating an ecological approach wherein connections to the social and economic context are made explicit.

  11. Clinical utility of computed electrocardiographic leads.

    Science.gov (United States)

    Batchvarov, Velislav N; Behr, Elijah R

    2014-01-01

    The standard 12-lead electrocardiogram (ECG) is only one of the possible ways to present the voltage differences between the nine recording electrodes. Other "non-conventional" leads may be constructed by physically connecting two or more electrodes in a different manner or by computation from the digital 12-lead ECG. Examples include bipolar or multipolar precordial leads and bipolar chest leads (between one precordial and one limb electrode). Such leads can remove or decrease noise originating from a limb cable/electrode that is present in the unipolar precordial leads. They can be diagnostically useful in Brugada syndrome and can display QRS fractionation that is not visible in the respective unipolar precordial or limb leads. Multipolar precordial leads sometimes display potentially useful information that is not visible in the respective unipolar leads and in bipolar leads computed from them. In conclusion, these computed ECG leads represent a potentially useful supplement to the conventional 12-lead ECG. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. First detection of lead in black paper from intraoral film

    Energy Technology Data Exchange (ETDEWEB)

    Guedes, Debora F.C., E-mail: defcg@usp.br [Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirao Preto, Universidade de Sao Paulo, Av. do Cafe, S/N, Monte Alegre, CEP 14040-904, Ribeirao Preto, SP (Brazil); Silva, Reginaldo S. [Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirao Preto, Universidade de Sao Paulo, Av. do Cafe, S/N, Monte Alegre, CEP 14040-904, Ribeirao Preto, SP (Brazil); Veiga, Marcia A.M.S. da [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. do Cafe, S/N, Monte Alegre, CEP 14040-904, Ribeirao Preto, SP (Brazil); Pecora, Jesus D. [Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirao Preto, Universidade de Sao Paulo, Av. do Cafe, S/N, Monte Alegre, CEP 14040-904, Ribeirao Preto, SP (Brazil)

    2009-10-30

    Lead (Pb) contamination in the black paper that recovers intraoral films (BKP) has been investigated. BKP samples were collected from the Radiology Clinics of the Dental School of Ribeirao Preto, University of Sao Paulo, Brazil. For sake of comparison, four different methods were used. The results revealed the presence of high lead levels, well above the maximum limit allowed by the legislation. Pb contamination levels achieved after the following treatments: paper digestion in nitric acid, microwave treatment, DIN38414-54 method and TCLP method were 997 {mu}g g{sup -1}, 189 {mu}g g{sup -1}, 20.8 {mu}g g{sup -1}, and 54.0 {mu}g g{sup -1}, respectively. Flame atomic absorption spectrometry (FAAS) and inductively coupled plasma mass spectrometry (ICP-MS) were employed for lead determination according to the protocols of the applied methods. Lead contamination in used BKP was confirmed by scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDS). All the SEM imaging was carried out in the secondary electron mode (SE) and backscattered-electron mode (QBSD) following punctual X-ray fluorescence spectra. Soil contamination derived from this product revealed the urgent need of addressing this problem. These elevated Pb levels, show that a preliminary treatment of BKP is mandatory before it is disposed into the common trash. The high lead content of this material makes its direct dumping into the environment unwise.

  13. Plant mediated detoxification of mercury and lead

    Directory of Open Access Journals (Sweden)

    Brajesh Kumar

    2017-05-01

    Full Text Available In recent years, the development of efficient green chemistry methods for detoxification of metal poisoning has become a major focus of researchers. They have investigated in order to find an eco-friendly and recyclable technique for the removal of heavy metal (Pb2+, Hg2+ contamination from the natural resources. One of the most considered methods is the removal of Pb2+, Hg2+ metal using green plants and their wastes. Among these plant wastes seem to be the best candidates and they are suitable for detoxification of heavy metals. Biosorption by plants involve complex mechanisms, mainly ion exchange, chelation, adsorption by physical forces and ion entrapment in inter and intra fibrillar capillaries and spaces of the structural polysaccharide cell wall network. The advantages of using green plants and their wastes for detoxification of heavy metal have interested researchers to investigate mechanisms of metal ion uptake, and to understand the possible utilization. In this review, we discuss the role of plants and their wastes for minimizing mercury and lead pollution with their toxic effect on both human beings and plants.

  14. [Determination of lead by atomic absorption spectrophotometry with regard to toxicology research].

    Science.gov (United States)

    Oudart, N; Guichard, C; Delage, C

    1976-01-01

    The toxicity of lead in the human environment is acquiring a growing interest which lead us to choose a quick, precise, sensitive and specific method able to perform number of measurements. Thanks to the survey consisting in a dosage of lead by atomic-absorption spectrometric, we are able to confirm the advantages and superiority of such a method and to employ it for the toxicologic research of lead in food, water, industrial atmosphere, and biological liquids.

  15. Lead Smelting and Refining at Kosaka Smelter

    National Research Council Canada - National Science Library

    MITSUNE, Yutaka; SATOH, Shigeki

    2007-01-01

      Kosaka Smelting and Refining Co., Ltd. operates lead smelting to produce electrolytic lead and to recover precious metals and bismuth with mainly secondary materials from copper smelter and zinc refinery...

  16. Some Lead Poisoning Tests May Be Faulty

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_165668.html Some Lead Poisoning Tests May Be Faulty But the majority of ... More Health News on Children's Health Laboratory Tests Lead Poisoning Recent Health News Related MedlinePlus Health Topics Children's ...

  17. Lead Poisoning in Remodeling of Old Homes

    Science.gov (United States)

    Barnes, Bart

    1973-01-01

    An article based on Dr. Muriel D. Wolf's study of elevated blood lead levels in children and adults present during the remodeling of old homes. Lead poisoning examples, symptoms, and precautions are given. (ST)

  18. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... language and behavioural problems [3]. Pregnant women and young children are particularly vul- nerable to lead ... However, this is controlled by a combination of several factors .... placement of tin-lead solders. Contact ...

  19. A Public Health Approach to Addressing Lead

    Science.gov (United States)

    Describes EPA’s achievements in reducing childhood lead exposures and emphasizes the need to continue actions to further reduce lead exposures, especially in those communities where exposures remain high.

  20. Observations on lead pollution in milk

    Energy Technology Data Exchange (ETDEWEB)

    Maffeo, G.; Renon, P.

    1976-08-01

    The problem of lead pollution in milk in highly industrialized areas (district of Milan) has been evaluated. Potentially dangerous rates of lead have been checked in milk, agricultural fields, fodders and entrails of slaughtered animals.

  1. A Comparative Study of Defibrillator Leads at a Large-Volume Implanting Hospital: Results From the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS").

    Science.gov (United States)

    Cohen, Todd J; Asheld, Wilbur J; Germano, Joseph; Islam, Shahidul; Patel, Dhimesh

    2015-06-01

    The purpose of the study was to examine survival in the implantable defibrillator subset of implanted leads at a large-volume implanting hospital. Implantable lead survival has been the subject of many multicenter studies over the past decade. Fewer large implanting volume single-hospital studies have examined defibrillator lead failure as it relates to patient survival and lead construction. This investigator-initiated retrospective study examined defibrillator lead failure in those who underwent implantation of a defibrillator between February 1, 1996 and December 31, 2011. Lead failure was defined as: failure to capture/sense, abnormal pacing and/or defibrillator impedance, visual insulation defect or lead fracture, extracardiac stimulation, cardiac perforation, tricuspid valve entrapment, lead tip fracture and/or lead dislodgment. Patient characteristics, implant approach, lead manufacturers, lead models, recalled status, patient mortality, and core lead design elements were compared using methods that include Kaplan Meier analysis, univariate and multivariable Cox regression models. A total of 4078 defibrillator leads were implanted in 3802 patients (74% male; n = 2812) with a mean age of 70 ± 13 years at Winthrop University Hospital. Lead manufacturers included: Medtronic: [n = 1834; 801 recalled]; St. Jude Medical: [n = 1707; 703 recalled]; Boston Scientific: [n = 537; 0 recalled]. Kaplan-Meier analysis adjusted for multiple comparisons revealed that both Boston Scientific's and St. Jude Medical's leads had better survival than Medtronic's leads (PLead survival was comparable between Boston Scientific and St. Jude Medical (P=.80). A total of 153 leads failed (3.5% of all leads) during the study. There were 99 lead failures from Medtronic (5.4% failure rate); 56 were recalled Sprint Fidelis leads. There were 36 lead failures from St. Jude (2.1% failure rate); 20 were recalled Riata or Riata ST leads. There were 18 lead failures from Boston Scientific (3

  2. Localized accumulation of lead within and among bones from lead-dosed goats

    Energy Technology Data Exchange (ETDEWEB)

    Cretacci, Yan [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY 12201-0509 (United States); Department of Environmental Health Sciences, School of Public Health, The University at Albany, P.O. Box 509, Albany, NY 12201-0509 (United States); Parsons, Patrick J., E-mail: pparsons@wadsworth.org [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, NY 12201-0509 (United States); Department of Environmental Health Sciences, School of Public Health, The University at Albany, P.O. Box 509, Albany, NY 12201-0509 (United States)

    2010-01-15

    The principal aim of this study was to gain a better understanding of where lead (Pb) accumulates and how it is distributed, within the bones of dosed goats. Adult goats were periodically dosed with Pb over a number of years for the primary purpose of producing blood pools containing endogenously bound Pb, for the New York State Blood Lead Proficiency Testing Program. Bone samples (e.g., primarily tibia, femur, humerus, and radius) were collected post-mortem from 11 animals and were analyzed for Pb content by acid digestion and electrothermal atomic absorption spectrometry (ETAAS or GFAAS). Average tibia Pb levels were found to correlate strongly with the cumulative Pb dose (r{sup 2}=0.81). However, the concentration of Pb in different bones and even within a small area of the same bone varied tremendously. Blood-rich trabecular (spongy) bone, such as the patella and calcaneus, were much more enriched in Pb than was cortical (compact) bone. In some dosed animals, the Pb concentration in the tibia was markedly higher at the proximal and distal ends of the bone compared to the mid-shaft. The implications of these findings with regard to the noninvasive measurement of lead in bone by XRF methods are discussed.

  3. Evaluation of the relationship between blood lead level and prevalence of oral complications in Koushk lead mine workers, Yazd province

    Directory of Open Access Journals (Sweden)

    Tabrizizadeh M

    2006-06-01

    Full Text Available Background and Aim: Lead is one of the most dangerous metallic poisons which can lead to acute and chronic poisoning with a broad range of systemic and oral signs. The aim of this study was to evaluate the relationship between the prevalence of oral complications and blood lead level in workers employed in Koushk lead mines, Yazd province. Materials and Methods: This analytical study was conducted on 70 subjects employed in Koushk lead mines and 70 workers in Yazdbaf textile factory as control group. A questionnaire including demographic information and medical questions was completed for each case and oral manifestations were recorded, as well. Blood samples were taken from subjects and blood lead level was measured by atomic absorption spectrophotometer. Data were analyzed using t, Chi-Square and Mann Whitney tests with p<0.05 as the limit of significance. Results: The mean lead level was 7.06 µg/dl in case group and 4.97µg/dl in control group (P= 0.039. In case group, 3 subjects had blood lead level more than 20µg/dl. Statistical analysis showed significant differences regarding neurologic disorder, chronic fatigue, existence of lead line, mucous pigmentation, gingivitis, tongue burning, taste sense reduction and DMF between case and control groups (P<0.05. Conclusion: Based on the results of this study, since the mean blood lead level in mine workers was in normal limits, the observed symptoms were not related to systemic poisoning. Direct contact of the oral mucosa with the lead in breathing air or other factors related to overall health problems in mine workers may be responsible for the present findings. Further studies are recommended on similar subjects working in different conditions.

  4. Investigation and Evaluation of Children’s Blood Lead Levels around a Lead Battery Factory and Influencing Factors

    Directory of Open Access Journals (Sweden)

    Feng Zhang

    2016-05-01

    Full Text Available Lead pollution incidents have occurred frequently in mainland China, which has caused many lead poisoning incidents. This paper took a battery recycling factory as the subject, and focused on measuring the blood lead levels of environmental samples and all the children living around the factory, and analyzed the relationship between them. We collected blood samples from the surrounding residential area, as well as soil, water, vegetables. The atomic absorption method was applied to measure the lead content in these samples. The basic information of the generation procedure, operation type, habit and personal protect equipment was collected by an occupational hygiene investigation. Blood lead levels in 43.12% of the subjects exceeded 100 μg/L. The 50th and the 95th percentiles were 89 μg/L and 232 μg/L for blood lead levels in children, respectively, and the geometric mean was 94 μg/L. Children were stratified into groups by age, gender, parents’ occupation, distance and direction from the recycling plant. The difference of blood lead levels between groups was significant (p < 0.05. Four risk factors for elevated blood lead levels were found by logistic regression analysis, including younger age, male, shorter distance from the recycling plant, and parents with at least one working in the recycling plant. The rate of excess lead concentration in water was 6.25%, 6.06% in soil and 44.44% in leaf vegetables, which were all higher than the Chinese environment standards. The shorter the distance to the factory, the higher the value of BLL and lead levels in vegetable and environment samples. The lead level in the environmental samples was higher downwind of the recycling plant.

  5. Leading Change: Military Leadership in Civilian Organizations

    Science.gov (United States)

    2012-03-19

    lead to a very frustrating stalemate for both the military leader and the organization they join. LEADING CHANGE: MILITARY LEADERSHIP IN...Civilian adds, “For the military leader , managing a civilian workforce is different from leading military subordinates.”4 Military members must...must plot a course to get the organization on the right path. Finally, the leader must lead and manage change in their organization while keeping

  6. Lead exposure from aluminum cookware in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Weidenhamer, Jeffrey D.; Kobunski, Peter A. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Kuepouo, Gilbert [Research and Education Centre for Development (CREPD), Yaounde (Cameroon); Corbin, Rebecca W. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Gottesfeld, Perry, E-mail: pgottesfeld@okinternational.org [Occupational Knowledge International, San Francisco, CA (United States)

    2014-10-15

    Blood lead levels have decreased following the removal of lead from gasoline in most of the world. However, numerous recent studies provide evidence that elevated blood lead levels persist in many low and middle-income countries around the world at much higher prevalence than in the more developed countries. One potential source of lead exposure that has not been widely investigated is the leaching of lead from artisanal aluminum cookware, which is commonly used in the developing world. Twenty-nine samples of aluminum cookware and utensils manufactured by local artisans in Cameroon were collected and analyzed for their potential to release lead during cooking. Source materials for this cookware included scrap metal such as engine parts, radiators, cans, and construction materials. The lead content of this cookware is relatively low (< 1000 ppm by X-ray fluorescence), however significant amounts of lead, as well as aluminum and cadmium were released from many of the samples using dilute acetic acid extractions at boiling and ambient temperatures. Potential exposures to lead per serving were estimated to be as high as 260 μg, indicating that such cookware can pose a serious health hazard. We conclude that lead, aluminum and cadmium can migrate from this aluminum cookware during cooking and enter food at levels exceeding recommended public health guidelines. Our results support the need to regulate lead content of materials used to manufacture these pots. Artisanal aluminum cookware may be a major contributor to lead poisoning throughout the developing world. Testing of aluminum cookware in other developing countries is warranted. - Highlights: • Cookware is manufactured in Cameroon from scrap aluminum including car parts. • Twenty-nine cookware samples were evaluated for their potential to leach lead. • Boiling extractions to simulate the effects of cooking released significant lead. • Potential lead exposures per serving are estimated as high as 260 μg.

  7. Developmental Effects of Lead Exposure in Children.

    Science.gov (United States)

    Tesman, Johanna Rich; Hills, Amanda

    1994-01-01

    This report presents an overview of research on childhood lead exposure and poisoning, and the related social issues. The report first summarizes the history of lead poisoning and its prevalence in the United States, and discusses the basis for recent changes in guidelines for lead exposure by the Centers for Disease Control (CDC). The report then…

  8. Hematological evaluation of lead intoxication in mallards

    Energy Technology Data Exchange (ETDEWEB)

    Mautino, M.; Bell, J.U.

    1987-01-01

    The measurement of blood lead has been the most widely accepted laboratory test for monitoring environmental lead exposure. Many technical difficulties are inherent in the precise quantification of blood lead at low concentrations and a margin of error of fifteen percent is not uncommon. Measurement of critical biochemical alterations resulting from lead exposure may provide a better indication of the toxic response of an individual than the actual measurement of blood lead. Lead exposure alters a number of enzymes resulting in impaired heme synthesis and an elevation or excretion of intermediates. Although the determination of blood lead has been the reference standard for monitoring lead exposure, the measurement of delta-aminolevulinic acid dehydratase activity (delta-ALAD) and free erythrocyte protoporphyrin concentrations (FEP) have been utilized to evaluate the extent of lead exposure in several species. In humans, there is a good correlation between both delta-ALAD and FEP and the deleterious effects seen following lead exposure. In avian species, investigators have measured elevated lead concentrations and an inhibition of delta-ALAD activity in lead-dosed mallards.

  9. Is Your Child Safe from Lead Poisoning?

    Centers for Disease Control (CDC) Podcasts

    2008-10-02

    In this podcast, Dr. Mary Jean Brown, chief of CDC's Lead Poisoning and Prevention Program, discusses the importance of testing children for lead poisoning, who should be tested, and what parents can do to prevent lead poisoning.  Created: 10/2/2008 by National Center for Environmental Health (NCEH).   Date Released: 10/2/2008.

  10. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... wettability, solder, lead, alloy, tin. 1. Introduction. Tin-lead solder has been the standard mate- rial used in electronic, chemical, automotive and other industries due to its low cost and unique material properties like low melting point, avail- ability etc. However, the toxicity of lead during industrial production of ...

  11. Lead poisoning of a marbled godwit

    Science.gov (United States)

    Locke, L.N.; Smith, M.R.; Windingstad, R.M.; Martin, S.J.

    1991-01-01

    A thin adult female marbled godwit (Limosa fedoa) found dead at Benton Lake National Wildlife Refuge, Montana, was found to have 17 ingested lead shot in its gizzard. Its liver contained 51.7 ppm lead (wet weight). Based on these necropsy findings a diagnosis of lead poisoning was made.

  12. Childhood Lead Poisoning: Blueprint for Prevention.

    Science.gov (United States)

    Rochow, K. W. James; Rapuano, Maria

    Current programs to deal with childhood lead poisoning, the primary environmental disease of U.S. children, screen individual children, treat those with serious cases of lead poisoning, and subsequently return children to hazardous environments. This approach has led to repeated diagnoses of lead poisoning. This handbook is designed to convince…

  13. Historical View on Lead: Guidelines and Regulations.

    Science.gov (United States)

    Pohl, Hana R; Ingber, Susan Z; Abadin, Henry G

    2017-04-10

    Lead has been used in many commodities for centuries. As a result, human exposure has occurred through the production and use of these lead-containing products. For example, leaded gasoline, lead-based paint, and lead solder/pipes in water distribution systems have been important in terms of exposure potential to the general population. Worker exposures occur in various industrial activities such as lead smelting and refining, battery manufacturing, steel welding or cutting operations, printing, and construction. Some industrial locations have also been a source of exposure to the surrounding communities. While the toxicity of relatively high lead exposures has been recognized for centuries, modern scientific studies have shown adverse health effects at very low doses, particularly in the developing nervous system of fetuses and children. This chapter reflects on historical and current views on lead toxicity. It also addresses the development and evolution of exposure prevention policies. As discussed here, these lead policies target a variety of potential exposure routes and sources. The changes reflect our better understanding of lead toxicity. The chapter provides lead-related guidelines and regulations currently valid in the U. S. and in many countries around the world. The reader will learn about the significant progress that has been made through regulations and guidelines to reduce exposure and prevent lead toxicity.

  14. LEAD POISONING IN ANCIENT ROME 1. INTRODUCTION

    African Journals Online (AJOL)

    of organic lead compounds such as tetra-ethyl lead, found in modern .... organic bone matrix. An adjustment formula taking the age of the adult into consideration is therefore necessary. There is no difference in bone lead content between men and women ... architect, Vitruvius (viii.6.10, 11), tells us that water from clay pipes.

  15. Load Dependent Lead Times and Sustainability

    DEFF Research Database (Denmark)

    Pahl, Julia; Voss, Stefan

    2016-01-01

    to prevent decreased quality or waste of production parts and products. This gains importance because waiting times imply longer lead times charging the production system with work in process inventories. Longer lead times can lead to quality losses due to depreciation, so that parts need to be reworked...

  16. Electrical polarization of lead bromide crystals. I

    NARCIS (Netherlands)

    Schoonman, A.; Macke, A.J.H.

    An attempt was made to measure electronic conductivity in lead bromide in equilibrium with lead, since experimental data on the cell −Pb/PbBr2/C+ in the literature are not consistent with existing theories. Combination of our results with published data for bromine-induced hole conduction in lead

  17. LEAD POISONING IN ANCIENT ROME 1. INTRODUCTION

    African Journals Online (AJOL)

    development of the region and the course of its history. 2. THE LEAD INDUSTRY IN ANCIENT ROME. 2.1 Lead production. From the 5th millennium BC ... production of olive oil were often made of or lined with lead (Cato,. De re rustica cv, lxvi). The wine fermentation process, too, often made use of casks or containers lined ...

  18. Distribution of Lead in Kerbside Soils

    African Journals Online (AJOL)

    NJD

    Lead in emissions from motor vehicles using leaded petrol are usually monitored by analysing gas samples. In view of the many problems associated with gas sampling, this project focussed on the analysis of lead in kerbside samples. To this end, soil .... was thoroughly mixed by shaking the soil in a clean plastic box.

  19. Early Reading Proficiency. Leading Indicator Spotlight

    Science.gov (United States)

    Musen, Lindsey

    2010-01-01

    In "Beyond Test Scores: Leading Indicators for Education," Foley and colleagues (2008) define leading indicators as those that "provide early signals of progress toward academic achievement" (p. 1) and stress that educators "need leading indicators to help them see the direction their efforts are going in and to take…

  20. Peripheral blood signatures of lead exposure.

    Directory of Open Access Journals (Sweden)

    Heather G LaBreche

    Full Text Available BACKGROUND: Current evidence indicates that even low-level lead (Pb exposure can have detrimental effects, especially in children. We tested the hypothesis that Pb exposure alters gene expression patterns in peripheral blood cells and that these changes reflect dose-specific alterations in the activity of particular pathways. METHODOLOGY/PRINCIPAL FINDING: Using Affymetrix Mouse Genome 430 2.0 arrays, we examined gene expression changes in the peripheral blood of female Balb/c mice following exposure to per os lead acetate trihydrate or plain drinking water for two weeks and after a two-week recovery period. Data sets were RMA-normalized and dose-specific signatures were generated using established methods of supervised classification and binary regression. Pathway activity was analyzed using the ScoreSignatures module from GenePattern. CONCLUSIONS/SIGNIFICANCE: The low-level Pb signature was 93% sensitive and 100% specific in classifying samples a leave-one-out crossvalidation. The high-level Pb signature demonstrated 100% sensitivity and specificity in the leave-one-out crossvalidation. These two signatures exhibited dose-specificity in their ability to predict Pb exposure and had little overlap in terms of constituent genes. The signatures also seemed to reflect current levels of Pb exposure rather than past exposure. Finally, the two doses showed differential activation of cellular pathways. Low-level Pb exposure increased activity of the interferon-gamma pathway, whereas high-level Pb exposure increased activity of the E2F1 pathway.

  1. A green lead hydrometallurgical process based on a hydrogen-lead oxide fuel cell.

    Science.gov (United States)

    Pan, Junqing; Sun, Yanzhi; Li, Wei; Knight, James; Manthiram, Arumugam

    2013-01-01

    The automobile industry consumed 9 million metric tons of lead in 2012 for lead-acid batteries. Recycling lead from spent lead-acid batteries is not only related to the sustainable development of the lead industry, but also to the reduction of lead pollution in the environment. The existing lead pyrometallurgical processes have two main issues, toxic lead emission into the environment and high energy consumption; the developing hydrometallurgical processes have the disadvantages of high electricity consumption, use of toxic chemicals and severe corrosion of metallic components. Here we demonstrate a new green hydrometallurgical process to recover lead based on a hydrogen-lead oxide fuel cell. High-purity lead, along with electricity, is produced with only water as the by-product. It has a >99.5% lead yield, which is higher than that of the existing pyrometallurgical processes (95-97%). This greatly reduces lead pollution to the environment.

  2. Eryptosis in lead-exposed workers

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Dorado, Itzel-Citlalli [Biochemistry Department, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico); Hernández, Gerardo [Section of Methodology of Science, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico); Quintanar-Escorza, Martha-Angelica [Faculty of Medicine, UJED, Durango, DGO (Mexico); Maldonado-Vega, María [CIATEC, León, GTO (Mexico); Rosas-Flores, Margarita [Biochemistry Department, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico); Calderón-Salinas, José-Víctor, E-mail: jcalder@cinvestav.mx [Biochemistry Department, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico)

    2014-12-01

    Eryptosis is a physiological phenomenon in which old and damaged erythrocytes are removed from circulation. Erythrocytes incubated with lead have exhibited major eryptosis. In the present work we found evidence of high levels of eryptosis in lead exposed workers possibly via oxidation. Blood samples were taken from 40 male workers exposed to lead (mean blood lead concentration 64.8 μg/dl) and non-exposed workers (4.2 μg/dl). The exposure to lead produced an intoxication characterized by 88.3% less δ-aminolevulinic acid dehydratase (δALAD) activity in lead exposed workers with respect to non-lead exposed workers. An increment of oxidation in lead exposed workers was characterized by 2.4 times higher thiobarbituric acid-reactive substance (TBARS) concentration and 32.8% lower reduced/oxidized glutathione (GSH/GSSG) ratio. Oxidative stress in erythrocytes of lead exposed workers is expressed in 192% higher free calcium concentration [Ca{sup 2+}]{sub i} and 1.6 times higher μ-calpain activity with respect to non-lead exposed workers. The adenosine triphosphate (ATP) concentration was not significantly different between the two worker groups. No externalization of phosphatidylserine (PS) was found in non-lead exposed workers (< 0.1%), but lead exposed workers showed 2.82% externalization. Lead intoxication induces eryptosis possibly through a molecular pathway that includes oxidation, depletion of reduced glutathione (GSH), increment of [Ca{sup 2+}], μ-calpain activation and externalization of PS in erythrocytes. Identifying molecular signals that induce eryptosis in lead intoxication is necessary to understand its physiopathology and chronic complications. - Graphical abstract: Fig. 1. (A) Blood lead concentration (PbB) and (B) phosphatidylserine externalization on erythrocyte membranes of non-lead exposed (□) and lead exposed workers (■). Values are mean ± SD. *Significantly different (P < 0.001). - Highlights: • Erythrocytes of lead exposed workers

  3. Lead, mercury, and cadmium in breast milk

    Directory of Open Access Journals (Sweden)

    Kadriye Yurdakök

    2015-10-01

    Full Text Available Toxic heavy metals are the major source of environmental pollution in this new millennium. Lead, mercury, and cadmium are the most common toxic heavy metals in the environment. There is no known function of these toxic heavy metals in the human body. In females, toxic heavy metals can be accumulated in maternal body before pregnancy and may be transferred to fetus through placenta and later, via breast milk. Lead previously accumulated in maternal bones can be mobilized along with calcium in order to meet increased calcium needs of the fetus in pregnant women and for the calcium needs in human milk during lactation. Human fetus and infants are susceptible to heavy metal toxicity passing through placenta and breastmilk due to rapid growth and development of organs and tissues, especially central nervous system. However most of the damage is already done by the time the infant is born. Intrauterine lead exposure can cause growth retardation, cognitive dysfunction, low IQ scores on ability tests, and low performance in school. Biological samples, such as umbilical cord blood and breast milk, and less commonly infant hair, are used for biomonitoring of intra-uterine exposure to these toxic chemicals. Although toxic metals and other pollutants may be excreted into breast milk, their effects are unknown and this topic is subject of a growing body of research. Despite the possibility of harm from environmental contaminants in breast milk, breastfeeding is still recommended as the best infant feeding method. In fact, the species-specific components present in breast milk protect infants against infections; promote immune and neurologic system development; and may decrease the risk of disease, including allergies, obesity, insulin-dependent diabetes mellitus, inflammatory bowel disease, and sudden infant death syndrome. Breastfeeding also facilitates maternal-infant attachment. The potential risk of environmental contaminants that can be transferred from

  4. Eliminating Childhood Lead Poisoning: A Federal Strategy Targeting Lead Paint Hazards.

    Science.gov (United States)

    2000

    Noting that lead poisoning is a preventable disease, this report details a coordinated federal program to eliminate childhood lead poisoning in the United States. The report describes how lead poisoning harms children, how pervasive lead poisoning is, and how lead paint hazards in housing could be eliminated in 10 years. Following information on…

  5. European survey on the content of lead in lip products.

    Science.gov (United States)

    Piccinini, Paola; Piecha, Małgorzata; Torrent, Salvador Fortaner

    2013-03-25

    223 lip articles (representing 55 brands) were purchased in 15 European Union Member States and analysed for lead content. Various lip products (lipsticks and lip glosses), shades (red, brown, purple and pink) and price ranges (3 categories) were investigated. The analytical method employed a microwave-assisted acid digestion followed by ICP-MS determination. The results revealed that 49 samples (22%) contained lead at a level higher than 1mg/kg, representing 31% of the tested lipsticks and 4% of the lip glosses. On average, the lead content found in lipsticks (0.75mg/kg) was nearly double that found in lip glosses (0.38mg/kg) and this difference was judged statistically significant at 95% probability. Apart from brown, statistically significant higher levels of lead were also found when comparing the average lead contents in lipsticks and lip glosses of the same shade: pink (0.81 and 0.38mg/kg), purple (0.88 and 0.37mg/kg) and red (0.58 and 0.25mg/kg). The influence of price on lead content was studied on the two lip product types separately. In the case of lip glosses no differences were found. In the case of lipsticks, the more expensive items (price category III) contained a significantly lower quantity of lead in comparison to the cheapest articles (price category I). The lipsticks containing the highest levels of lead belonged to the price category II. In all cases, however, the actual lead concentration measured in the finished products is far below the recommended limits for Germany (20mg/kg) or Canada (10mg/kg). The outcome of this work delivers information about the current situation on the European market and provides information to policy-makers about the quantities of lead in lip articles and technically achievable levels. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. SU-E-P-09: Radiation Transmission Measurements and Evaluation of Diagnostic Lead-Based and Lead-Free Aprons

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2014-06-01

    Purpose: This study was conducted to ensure that various lead shield apron manufacturers provided accurate attenuation factors regardless of whether the apron was made of lead-based or lead-free equivalent material. Methods: A calibrated ionization survey meter was placed at chest height and 36 cm horizontally away from a solid water phantom on a simulator couch. Measurements were done with or without apron. Radiation field was set to 24cmx24cm with the phantom at 100cm source-to-surface distance. Irradiation time was set for 1 minute at voltages of 60, 80, 100 and 120 kVp. Current was set at 6mA. Results: Between 60 kVp and 120 kVp, the transmission through 0.50 mm of lead-based apron was between 1.0% and 6.5% with a mean value of 3.2% and a standard deviation (s.d.) of 1.4%. The transmissions through the 0.50 mm lead-free aprons were 1.0 % to 12.0% with a mean value of 6.1% and s.d. of 2.6%. At 120 kVp, the transmission value was 6.5% for 0.50 mm lead-based apron and 11.1% to 12.0% for 0.50 mm lead-free aprons. The radiation transmissions at 80 kVp, measured in two different 0.5 mm lead-free aprons, were 4.3% each. However, only 1.4% transmission was found through the lead-based apron. Overall, the radiation transmitted through the lead-based apron was 1/3 transmission of lead-free at 80kVp, and half value of lead-free aprons at 100 and 120 kVp. Conclusion: Even though lead-based and lead-free aprons all claimed to have the same lead equivalent thickness, the transmission might not be the same. The precaution was needed to exercise diligence in quality assurance program to assure adequate protection to staff who wear it during diagnostic procedures. The requirement for aprons not only should be in certain thickness to meet state regulation but also to keep reasonably achievable low exposure with the accurate labeling from manufacturers.

  7. Symmetric airfoil geometry effects on leading edge noise.

    Science.gov (United States)

    Gill, James; Zhang, X; Joseph, P

    2013-10-01

    Computational aeroacoustic methods are applied to the modeling of noise due to interactions between gusts and the leading edge of real symmetric airfoils. Single frequency harmonic gusts are interacted with various airfoil geometries at zero angle of attack. The effects of airfoil thickness and leading edge radius on noise are investigated systematically and independently for the first time, at higher frequencies than previously used in computational methods. Increases in both leading edge radius and thickness are found to reduce the predicted noise. This noise reduction effect becomes greater with increasing frequency and Mach number. The dominant noise reduction mechanism for airfoils with real geometry is found to be related to the leading edge stagnation region. It is shown that accurate leading edge noise predictions can be made when assuming an inviscid meanflow, but that it is not valid to assume a uniform meanflow. Analytic flat plate predictions are found to over-predict the noise due to a NACA 0002 airfoil by up to 3 dB at high frequencies. The accuracy of analytic flat plate solutions can be expected to decrease with increasing airfoil thickness, leading edge radius, gust frequency, and Mach number.

  8. Delayed visual maturation and lead pollution.

    Science.gov (United States)

    Gulson, B L; Yui, L A; Howarth, D

    1998-12-11

    Three children were born in the Broken Hill Australia lead mining community with delayed visual maturation of the optic nerve (blindness) within a period of 19 months. Because of the association with the lead pollution, the delayed visual maturation was attributed to lead exposure of the fetus during pregnancy. Lead isotopic analyses of the shed deciduous teeth from the three children demonstrate that they were not exposed to increased levels of lead from a mining or any other source during pregnancy and the etiology of the delayed visual maturation must be sought elsewhere.

  9. Occupational lead exposure and renin release.

    Science.gov (United States)

    Campbell, B C; Beattie, A D; Elliott, H L; Goldberg, A; Moore, M R; Beevers, D G; Tree, M

    1979-01-01

    Hypertension may result from chronic lead exposure. Lead poisoning arising from "moonshine whiskey" drinking has been associated with a rise in plasma renin activity. In the present study, plasma renin concentration following intravenous administration of frusemide was measured in eleven subjects with moderate or severe lead poisoning of industrial origin. The results were compared with those obtained for seven normal, control subjects. There was no significant difference in response obtained in the two groups. Industrial lead poisoning does not appear to affect renin release. The combined insult of lead and alcohol may explain the findings in the previous study.

  10. Percutaneous extraction of stented device leads.

    Science.gov (United States)

    Baranowski, Bryan; Wazni, Oussama; Chung, Roy; Martin, David O; Rickard, John; Tanaka-Esposito, Christine; Bassiouny, Mohammed; Wilkoff, Bruce L

    2012-05-01

    There are limited published data regarding the percutaneous extraction of device leads jailed by a venous stent. In this study we assessed the feasibility and safety of percutaneous extraction of stented device leads. We reviewed our experience percutaneously extracting 7 chronically implanted device leads jailed to the wall of the left innominate and/or subclavian veins by a previously placed stent. All leads were successfully extracted by using a percutaneous approach. Both pacing leads and defibrillator leads were extracted. The oldest pacing lead extracted was 14 years old. The oldest defibrillator lead extracted was 6 years old. Three of the leads were extracted with simple manual traction alone. The 4 remaining leads required a more complex, femoral extraction approach for successful removal. In our experience extracting 7 stented device leads, complete percutaneous removal was feasible 100% of the time using a combination of simple manual traction and a femoral approach. No major complications were associated with the extraction procedures. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  11. Lead sources in human diet in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Johansen, Poul; Mulvad, Gert

    2004-01-01

    Although blood lead levels have declined in Greenland, they are still elevated despite the fact that lead levels in the Greenland environment are very low. Fragments of lead shot in game birds have been suggested as an important source of dietary exposure, and meals of sea birds, particularly eider......, contain high concentrations of lead. In a cross-sectional population survey in Greenland in 1993-1994, blood lead adjusted for age and sex was found to be associated with the reported consumption of sea birds. Participants reporting less than weekly intake of sea birds had blood lead concentrations...... of approximately 75 microg/L, whereas those who reported eating sea birds several times a week had concentrations of approximately 110 microg/L, and those who reported daily intake had concentrations of 170 microg/L (p = 0.01). Blood lead was not associated with dietary exposure to other local or imported food...

  12. How lead loses its toxicity to plants

    Directory of Open Access Journals (Sweden)

    Małgorzata Wierzbicka

    2014-01-01

    Full Text Available This paper is a brief review of the problem of lead-in the environment, particularly constitutional tolerance to lead about which little is known. Taking Allium cepa L. roots as a model it has been shown that after an initial phase in which lead is toxic to cells, defence processes appear with the results that lead is no longer poisonous. The lead which penetrates into the root symplast is detoxified in vacuoles, cell walls and dictiosomal vesicles. Initial cells of the meristem (quescent centre which play a basic role in the root regeneration processes are protected against lead penetration. This surprising result is in agreement with the absence of any symptoms of lead poisoning in plants growing in natural conditions, and suggests that there is a defence mechanism specific only for plant cells.

  13. Experimental oral lead toxicity in young dogs

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, H.D.; Goyer, R.A.; Krigman, M.M.; Wilson, M.; Cates, M.

    1973-02-01

    Litter-mate male pups were fed a calcium-and-phosphorus-low purified diet with and without 100 ppm of lead as lead acetate from age 6 to 18 weeks. Lead-toxic dogs exhibited cyclic but terminally severe anorexia and cachexia, significant anemia, normoblastocytosis and leukopenia within six weeks, hypoproteinemia, decreased serum albumin, ..cap alpha../sub 1/-globulin, ..beta../sub 2/-globulin, alkaline phosphatase and lactic dehydrogenase 1, elevated serum glutamic oxaloacetic and pyruvic transaminases, delayed closure of the thoracic vertebral epiphyses, lead lines in the distal radii and thoracic spinous processes, enlargement of liver, kidney, and brain, hepatic fatty metamorphosis, focal proximal renal tubular necrosis, hydropic degeneration of spermatognia, and lead inclusion body formation. Approximately 97% of the tissue lead was estimated to be skeletal; the greatest concentration of lead in the brain was found in the occipital gray matter.

  14. Editorial: Lead Risk Assessment and Health Effects.

    Science.gov (United States)

    Mielke, Howard W

    2016-06-14

    In 1980, Clair C. Patterson stated: "Sometime in the near future it probably will be shown that the older urban areas of the United States have been rendered more or less uninhabitable by the millions of tons of poisonous industrial lead residues that have accumulated in cities during the past century". We live in the near future about which this quote expressed concern. This special volume of 19 papers explores the status of scientific evidence regarding Dr. Patterson's statement on the habitability of the environments of communities. Authors from 10 countries describe a variety of lead issues in the context of large and small communities, smelter sites, lead industries, lead-based painted houses, and vehicle fuel treated with lead additives dispersed by traffic. These articles represent the microcosm of the larger health issues associated with lead. The challenges of lead risk require a concerted global action for primary prevention.

  15. CHARACTERISTICS OF RAT LIVER EXPOSED TO NANOPARTICLES OF LEAD COMPOUNDS.

    Science.gov (United States)

    Omelchuk, S; Aleksijchuk, V; Sokurenko, L; Blagaia, A; Prudchenko, S

    2016-12-01

    In recent times, the lead becomes great importance in environmental pollution, including its nanoparticles. In the literature, there is little data on the changes in the liver after the exposure with lead nanoparticles. The purpose of this study was the identification and determination of macroscopic, microscopic, and biochemical changes of the structural elements of the rat's liver exposed to the action of lead compounds. The study was carried out on 60 male Wistar rats. The first and second groups of animals were intraperitoneally injected with colloidal solution of nanoparticles of Lead Sulfide size of 10 nm and 30 nm, and the third group was intraperitoneally injected with a solution of nitrate lead. Macroscopic, histological, histochemical, biochemical methods and gas chromatography were used to identify the changes of fatty acids metabolism. The experiment has found that body weights of animals in all tested groups were decreased after 6 weeks of lead nanoparticles injection, while relative liver weight was increased. Levels of total lipids and cholesterol, total protein and albumin in the blood serum in study groups have decreased, and the level of triglycerides and glucose have increased. Moderate dystrophic changes were observed in the histological examinations of the liver, and this was confirmed by morphometric and densitometric parameters. Changes of fatty acid composition of lipids of the liver exposed to nanoparticles were the result of increasing arachidonic fatty acid content and reduction of the stearic fatty acid content. Thus, it has been proven by the experiment that the effect of lead nanoparticles depends on their size.

  16. Brainstem auditory evoked potentials in children with lead exposure

    Directory of Open Access Journals (Sweden)

    Katia de Freitas Alvarenga

    2015-02-01

    Full Text Available Introduction: Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. Objective: To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Methods: Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months. Results: The mean time-integrated cumulative blood lead index was 12 µg/dL (SD ± 5.7, range:2.433. All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. Conclusion: No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area.

  17. Behavioral effects of lead: commonalities between experimental and epidemiologic data.

    Science.gov (United States)

    Rice, D C

    1996-04-01

    Enormous effort has been focused over the last decade and a half on characterizing the behavioral effects of lead in the developing organism. While age-appropriate standardized measures of intelligence (IQ) have been the dependent variable most often used to assess lead-induced cognitive impairment in epidemiologic studies, researchers have also used a variety of other methods designed to assess specific behavioral processes sensitive to lead. Increased reaction time and poorer performance on vigilance tasks associated with increased lead body burden suggest increased distractibility and short attention span. Assessment of behavior on teachers' rating scales identified increased distractibility, impulsivity, nonpersistence, inability to follow sequences of directions, and inappropriate approach to problems as hallmarks of lead exposure. Robust deficits in learned skills such as reading, spelling, math, and word recognition have also been found. Spatial organizational perception and abilities seem particularly sensitive to lead-induced impairment. Assessment of complex tasks of learning and memory in both rats and monkeys has revealed overall deficits in function over a variety of behavioral tasks. Exploration of behavioral mechanisms responsible for these deficits identified increased distractibility perseveration, inability to inhibit inappropriate responding, and inability to change response strategy as underlying deficits. Thus, there is remarkable congruence between the epidemiologic and experimental literatures with regard to the behavioral processes identified as underlying the deficits inflicted by developmental lead exposure. However, careful behavioral analysis was required from researchers in both fields for such understanding to emerge.

  18. Anaerobic microbial dissolution of lead and production of organic acids

    Science.gov (United States)

    Francis, A.J.; Dodge, C.; Chendrayan, K.; Quinby, H.L.

    1987-04-16

    The present invention related to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rat of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 ..mu..moles of lead as lead oxide was 0.042 ..mu..moles m1/sup /-/1/ hr/sup /-/1/. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of the strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids. 4 figs., 3 tabs.

  19. On the String Averaging Method for Sparse Common Fixed Points Problems.

    Science.gov (United States)

    Censor, Yair; Segal, Alexander

    2009-07-01

    We study the common fixed point problem for the class of directed operators. This class is important because many commonly used nonlinear operators in convex optimization belong to it. We propose a definition of sparseness of a family of operators and investigate a string-averaging algorithmic scheme that favorably handles the common fixed points problem when the family of operators is sparse. The convex feasibility problem is treated as a special case and a new subgradient projections algorithmic scheme is obtained.

  20. Get the Lead Out: Facts about Childhood Lead Poisoning [and] Housekeeping Tips To Reduce Lead Exposure [and] Nutrition and Lead Poisoning [and] The Medical Consequences of Lead Poisoning [and] Lead Poisoning for Health Care Providers.

    Science.gov (United States)

    Illinois State Dept. of Public Health, Springfield.

    This document is comprised of five fact sheets from the Illinois Department of Public Health regarding childhood lead poisoning. Recent studies claim that childhood lead poisoning can contribute to problems later in life, such as academic failure, juvenile delinquency, and high blood pressure. Directed to parents, caregivers, and health care…

  1. Trader lead-lag networks and order flow prediction

    CERN Document Server

    Challet, Damien; Lallouache, Mehdi; Kassibrakis, Serge

    2016-01-01

    Using trader-resolved data, we document lead-lag relationships between groups of investors in the foreign exchange market. Because these relationships are systematic and persistent, order flow is predictable from trader-resolved order flow. We thus propose a generic method to exploit trader lead-lag and predict the sign of the total order imbalance over a given time horizon. It first consists in an unsupervised clustering of investors according to their buy/sell/inactivity synchronization. The collective actions of these groups and their lagged values are given as inputs to machine learning methods. When groups of traders and when their lead-lag relationships are sufficiently persistent, highly successful out-of-sample order flow sign predictions are obtained.

  2. Vagus nerve stimulation after lead revision.

    Science.gov (United States)

    Dlouhy, Brian J; Viljoen, Steven V; Kung, David K; Vogel, Timothy W; Granner, Mark A; Howard, Matthew A; Kawasaki, Hiroto

    2012-03-01

    Vagus nerve stimulation (VNS) has demonstrated benefit in patients with medically intractable partial epilepsy. As in other therapies with mechanical devices, hardware failure occurs, most notably within the VNS lead, requiring replacement. However, the spiral-designed lead electrodes wrapped around the vagus nerve are often encased in dense scar tissue hampering dissection and removal. The objective in this study was to characterize VNS lead failure and lead revision surgery and to examine VNS efficacy after placement of a new electrode on the previously used segment of vagus nerve. The authors reviewed all VNS lead revisions performed between October 2001 and August 2011 at the University of Iowa Hospitals and Clinics. Twenty-four patients underwent 25 lead revisions. In all cases, the helical electrodes were removed, and a new lead was placed on the previously used segment of vagus nerve. All inpatient and outpatient records of the 25 lead revisions were retrospectively reviewed. Four cases were second lead revisions, and 21 cases were first lead revisions. The average time to any revision was 5 years (range 1.8-11.1 years), with essentially no difference between a first and second lead revision. The most common reason for a revision was intrinsic lead failure resulting in high impedance (64%), and the most common symptom was increased seizure frequency (72%). The average duration of surgery for the initial implantation in the 15 patients whose VNS system was initially implanted at the authors' institution was much shorter (94 minutes) than the average duration of lead revision surgery (173 minutes). However, there was a significant trend toward shorter surgical times as more revision surgeries were performed. Sixteen of the 25 cases of lead revision were followed up for more than 3 months. In 15 of these 16 cases, the revision was as effective as the previous VNS lead. In most of these cases, both the severity and frequency of seizures were decreased to levels

  3. Exposure to lead from intake of coffee

    DEFF Research Database (Denmark)

    Hansen, Max; Sloth, Jens Jørgen; Rasmussen, Rie Romme

    Food and beverages is one of the primary sources of intake of and exposure to lead, with beverages accounting for almost 50%. Previous studies from Denmark have estimated that the intake of lead from coffee is very high and may contribute to up to 20% of the total lead intake from food and bevera......Food and beverages is one of the primary sources of intake of and exposure to lead, with beverages accounting for almost 50%. Previous studies from Denmark have estimated that the intake of lead from coffee is very high and may contribute to up to 20% of the total lead intake from food...... and beverages. This estimate is, however, based on older, non-published data. In the current project extensive chemical analyses of coffee beans, drinking water and ready-to-drink coffee have been performed. The results hereof have been compared to calculations of the total intake of lead from food...... and beverages. The results show that the intake of lead from coffee is considerably lower than previously estimated and account for 4.2% and 3.3% of the total lead intake from food and beverages for Danish men and women, respectively. It can generally be concluded that the intake of lead from coffee is low...

  4. Lead contamination of paint remediation workers' vehicles.

    Science.gov (United States)

    Boraiko, Carol; Wright, Eva M; Ralston, Faye

    2013-03-01

    Exposure to lead has been shown to be harmful to adults; it is a teratogen, it can damage the peripheral nervous system, and it adversely affects the reproductive system. Professional lead-based paint remediation workers are at risk of exposure to lead dust. The authors' study was conducted to determine if these remediation workers transfer lead from their work site to their vehicles and then potentially expose their families. It was hypothesized that remediation workers transported the lead from the remediation work site to the floorboards of their vehicles due to not following required protective equipment use. The laboratory's level of quantitation for lead on the wipe samples, 10 microg/ft2, was used to indicate lead contamination. This level was exceeded in 50% of the floorboards sampled. These results confirm that many vehicle floorboards used by remediation workers are contaminated with lead dust, potentially resulting in transfer of lead dust. The ultimate detrimental outcome could be the transfer of lead particles to other family members, causing the poisoning of a child or other at-risk person.

  5. Hypogonadism in chronically lead-poisoned men.

    Science.gov (United States)

    Braunstein, G D; Dahlgren, J; Loriaux, D L

    1978-01-01

    The hypothalamic-pituitary-testicular axis was evaluated in 10 men with occupational lead exposure, 9 of whom had noted a decrease in libido and frequency of intercourse following this exposure. 6 of these men had clinically apparent lead poisoning while 4 were classified as being only lead-exposed. Results of the endocrine evaluation of these patients were compared to those obtained on 9 age and socioeconomically matched control patients. Both lead poisoned and lead-exposed patients had reduced basal serum testosterone levels and normal basal serum testosterone-estradiol-binding globulin capacity, estradiol, LH, FSH, and prolactin levels. Both groups demonstrated an appropriate rise in serum testosterone following hCG stimulation and a normal increment in serum FSH in response to clomiphene citrate and gonadotropin-releasing hormone in comparison to the control group. The lead poisoned patients demonstrated a significantly reduced increment in serum LH after clomiphene citrate and gonadotropin-releasing hormone administration while the lead-exposed patients had normal LH dynamics. Testicular biopsies carried out on the 2 most severely lead-poisoned men showed peritubular fibrosis, oligospermia, and vacuolization of the Sertoli cells. These results suggest that lead poisoning may lead to a pituitary-hypothalamic defect in LH secretion and may also result in direct testicular seminiferous tubular injury.

  6. Lead in food and food containers

    Energy Technology Data Exchange (ETDEWEB)

    Chu, A.O. [Univ. of California, Berkeley, CA (United States)

    1994-04-01

    We investigated food and food containers suspected of containing high levels of lead. Food containers investigated were bought in Northern California and were linked to several cases of lead poisoning in children and adults. Coffee mugs and Mexican pottery were leached with acetic and citric acid, respectively. The amount of lead leached from the lip and rim area of eleven coffee mugs ranged from non detectable to 79 ppm. Lead leached from Mexican potteries ranged from non detectable to 584 ppm of lead. Although there are no regulations pertaining to the amount of lead in the lip and rim area of ceramic ware, under California proposition 65 vendors are required to warn consumers of the presence of toxic materials in consumer products. Foods analyzed for lead content were candy and beans. A sample of tamarindo candy taken from the center of its storage container, a mexican clay pot, was found to contain 1.0 ppm of lead, while the candy in contact with the glaze contained 16 ppm of lead. Beans cooked in Mexican clay cooking pots contained lead ranging from 2.8 to 9.2 ppm. Two-thirds of the food containers investigated and the food analyzed did not meet the provisional Total Tolerable Daily Intake level let by the U.S. FDA, assuming a reasonable amount of liquid and food was ingested.

  7. Lead exposure in US worksites: A literature review and development of an occupational lead exposure database from the published literature.

    Science.gov (United States)

    Koh, Dong-Hee; Locke, Sarah J; Chen, Yu-Cheng; Purdue, Mark P; Friesen, Melissa C

    2015-06-01

    Retrospective exposure assessment of occupational lead exposure in population-based studies requires historical exposure information from many occupations and industries. We reviewed published US exposure monitoring studies to identify lead measurement data. We developed an occupational lead exposure database from the 175 identified papers containing 1,111 sets of lead concentration summary statistics (21% area air, 47% personal air, 32% blood). We also extracted ancillary exposure-related information, including job, industry, task/location, year collected, sampling strategy, control measures in place, and sampling and analytical methods. The measurements were published between 1940 and 2010 and represented 27 2-digit standardized industry classification codes. The majority of the measurements were related to lead-based paint work, joining or cutting metal using heat, primary and secondary metal manufacturing, and lead acid battery manufacturing. This database can be used in future statistical analyses to characterize differences in lead exposure across time, jobs, and industries. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  8. Next-to-leading order corrections to the valon model

    Indian Academy of Sciences (India)

    A seminumerical solution to the valon model at next-to-leading order (NLO) in the Laguerre polynomials is presented. We used the valon model to generate the structure of proton with respect to the Laguerre polynomials method. The results are compared with H1 data and other parametrizations.

  9. determination of lead at nanogram level in water samples

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. A novel method of chemistry applicable to the determination of trace lead in water samples based on the resonance light scattering (RLS) technique has been developed. In dilute phosphoric acid medium, in the presence of a large excess of I-, Pb(II) can form [PbI4]2-, which further reacts with tetrabutyl ...

  10. Determination of lead at nanogram level in water samples by ...

    African Journals Online (AJOL)

    A novel method of chemistry applicable to the determination of trace lead in water samples based on the resonance light scattering (RLS) technique has been developed. In dilute phosphoric acid medium, in the presence of a large excess of I-, Pb(II) can form [PbI4]2-, which further reacts with tetrabutyl ammonium bromide ...

  11. derivative spectrophotometric determination of trace lead in alloys

    African Journals Online (AJOL)

    Chandravanshi

    diethylaminophenol- ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 4.0–6.0 from a large volume of aqueous solutions of various samples. After filtration, the solid mass consisting of the lead ...

  12. The Determination of Lead in Gasoline by Atomic Absorption Spectrometry.

    Science.gov (United States)

    Coleman, M. F. M.

    1985-01-01

    Describes an experiment that involves the extraction of lead from gasoline into an aqueous solvent using iodine monochloride reagent. This method (which avoids the aspiration of organic solvents) also illustrates the use of wavelengths other than the most sensitive wavelength and effects of flame stoichiometry and burner height upon absorbance.…

  13. Assessment of lead in cosmetic products.

    Science.gov (United States)

    Al-Saleh, Iman; Al-Enazi, Sami; Shinwari, Neptune

    2009-07-01

    There have been a number of recent reports in the media and on the internet about the presence of lead in brand-names lipsticks. This has drawn our attention to assess the safety of various cheap brands of cosmetics sold at 2-riyals stores in Saudi market that are imported from countries where safety regulations are poorly enforced as well as they lack perfect conditions for manufacturing. Lead contents were determined in 26 and eight different brands of lipsticks and eye shadows using the Zeeman atomic absorption spectrophotometer coupled to graphite tube atomizer after an acid digestion procedure. Lead was detected in all the studied samples. The median (25th-75th percentile) lead content in 72 lipsticks samples was 0.73 (0.49-1.793) PPM wet wt. in the range of 0.27-3760 PPM wet wt. There were four brands of lipsticks with lead content above the FDA lead limit as impurities in color additives (20 PPM). The FDA does not set a limit for lead in lipstick. Three of them were extremely high points and considered outliers. The median (25th-75th percentile) lead contents in pressed powder eye shadow was 1.38 (0.944-1.854) PPM wet wt. (n=22) in the range of 0.42-58.7 PPM wet wt. One brand was above 20 PPM the US FDA's lead limit as impurities. The overall results indicate that lead in lipsticks and eye shadows are below the FDA lead limit as impurities and, thus, probably have no significant toxicological effects. Nevertheless, few brands had lead content above 20 PPM that might put consumers at the risk of lead poisoning. Lead is a cumulative, and applying lead-containing cosmetics several times a day or every day, can potentially add up to significant exposure levels. Pregnant and nursing mothers are vulnerable population because lead passes through placenta and human milk and affect fetus or infant's developments. Our findings call for an immediate mandatory regular testing program to check lead and other toxic metals in lipsticks and other cosmetic products imported

  14. The refining of secondary lead for use in advanced lead-acid batteries

    Science.gov (United States)

    Ellis, Timothy W.; Mirza, Abbas H.

    Secondary lead, i.e. material produced by the recycling of lead-acid batteries has become the primary source of lead in much of the world. This has been important to the secondary lead industry as other uses have dwindled, e.g. lead based pigments, chemicals, fuel additives, solders and CRT glasses [1]. Presently, battery manufacturing accounts for greater than 80% of lead consumption while recycled lead accounts for approximately the same market share of lead supply. These two facts strongly demonstrate the battery manufacturing and recycled lead are intimately coupled in everyday life. In this paper we will explore how recycled lead has become the material of choice for battery construction through the development of a recovery and refining process that exceeds the industries requirements. Particular focus will be on addressing the results presented by Prengaman [2] on the effects of contaminant or tramp elements on gassing in lead-acid batteries.

  15. Lead Poisoning Due to Herbal Medications.

    Science.gov (United States)

    Chambial, Shailja; Bhardwaj, Pankaj; Mahdi, Abbas Ali; Sharma, Praveen

    2017-06-01

    Lead ranks as one of the most serious environmental poisons all over the world amongst toxic heavy metals with no known biological function useful for the human body. A case of lead toxicity due to consumption of herbal medicine is being discussed. The case presented with gastrointestinal complaints and history of intake of herbal medicines for diabetes control for past 8 months. The analysis of the powdered herbal medicine procured from ayurveda practitioner was found to have high content of lead responsible for the lead toxicity. The patient is under regular followup. He has improved symptomatically on chelating therapy and blood lead levels have gradually improved. Regular awareness programs should be conducted in the population regarding possible exposure through home made herbal remedies so that general public can be made aware of the dangerous side effects of lead and other heavy metals on health.

  16. Innovation Management, Lead Users and Social Media

    DEFF Research Database (Denmark)

    Ernst, M.; Brem, Alexander; Voigt, K.-I.

    2013-01-01

    to integrate external knowledge into innovation processes. This approach is discussed by considering the integration of customers and especially Lead-Users into corporate product development. Based on the concept of Open Innovation, we reflect the role of Lead-Users in the innovation process critically....... Mounting on our reflections, we show the potentials of social media for integrating Lead-Users and develop a conceptual framework for the integration of Lead-Users using different social media applications. Findings — In this paper, a conceptual framework for integrating Lead-Users by using different...... social media applications is developed and introduced. Originality/value — The unique conceptual framework derived in this chapter is enriched with a discussion of the challenges resulting from the implementation of Lead-User integration along with social media in corporate innovation management...

  17. Extraction of superfluous device leads: A comparison with removal of infected leads.

    Science.gov (United States)

    Huang, Xin-Miao; Fu, Haixia; Osborn, Michael J; Asirvatham, Samuel J; McLeod, Christopher J; Glickson, Michael; Acker, Nancy G; Friedman, Paul A; Cha, Yong-Mei

    2015-06-01

    Although increasingly more lead extraction was performed for superfluous leads, the extraction of such leads remains controversial. The objective of this study was to determine the outcomes and complications of transvenous extraction of superfluous leads in a single center in the era of laser technology. Four hundred eighty transvenous lead extraction procedures performed from January 2001 through October 2012 at Mayo Clinic (Rochester, Minnesota) were retrospectively reviewed. Of these, 123 procedures were performed for superfluous functional or nonfunctional leads. Data were collected from electronic medical records and an institutional database of cardiovascular implantable electronic devices. A total of 167 superfluous leads (mean [SD] lead duration 53 [53] months; median 34 months) were removed during the 123 procedures. Forty-one percent of procedures were for lead malfunction. The procedural complete-success rate was 96.7%. Major complications occurred in 1 patient (0.8%), who had a superior vena cava tear that required thoracotomy. Superfluous leads had been implanted for a shorter period of time than infected leads (mean [SD] 53 [53] vs 81 [59] months; P leads than for leads associated with infection (97% vs 92%; P = .05). Transvenous extraction of superfluous leads is highly successful, with few procedural complications. Extraction of superfluous leads at the time of device upgrade or lead revision is considered reasonable to avoid the increasing risk of extraction complications with lead aging. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  18. Lead in tissues of mallard ducks dosed with two types of lead shot

    Science.gov (United States)

    Finley, M.T.; Dieter, M.P.; Locke, L.N.

    1976-01-01

    Mallard ducks (Anas platyrhynchos) were sacrificed one month after ingesting one number 4 all-lead shot or one number 4 lead-iron shot. Livers, kidneys, blood, wingbones, and eggs were analyzed for lead by atomic absorption. Necropsy of sacrificed ducks failed to reveal any of the tissue lesions usually associated with lead poisoning in waterfowl. Lead levels in ducks given all-lead shot averaged about twice those in ducks given lead-iron shot, reflecting the amount of lead in the two types of shot. Lead in the blood of ducks dosed with all-lead shot averaged 0.64 ppm, and 0.28 ppm in ducks given lead-iron shot. Lead residues in livers and kidneys of females given all-lead shot were significantly higher than in males. In both dosed groups, lead levels in wingbones of females were about 10 times those in males, and were significantly correlated with the number of eggs laid after dosage. Lead levels in contents and shells of eggs laid by hens dosed with all-lead shot were about twice those in eggs laid by hens dosed with lead-iron shot. Eggshells were found to best reflect levels of lead in the blood. Our results indicate that mallards maintained on a balanced diet and dosed with one lead shot may not accumulate extremely high lead levels in the liver and kidney. However, extremely high lead deposition may result in the bone of laying hens after ingesting sublethal amounts of lead shot as a result of mobilization of calcium from the bone during eggshell formation.

  19. NASA DOD Lead Free Electronics Project

    Science.gov (United States)

    Kessel, Kurt R.

    2008-01-01

    The primary'technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIPD assembled and reworked with lead-free alloys Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  20. Lead in ancient Rome's city waters

    OpenAIRE

    Delile, Hugo; Blichert-Toft, Janne; Goiran, Jean-Philippe; Keay, Simon; Albarède, Francis

    2014-01-01

    International audience; It is now universally accepted that utilization of lead for domestic purposes and water distribution presents a major health hazard. The ancient Roman world was unaware of these risks. How far the gigantic network of lead pipes used in ancient Rome compromised public health in the city is unknown. Lead isotopes in sediments from the harbor of Imperial Rome register the presence of a strong anthropogenic component during the beginning of the Common Era and the Early Mid...