Relevant bibliographies by topics / Chemical sensitivity analysi

Academic literature on the topic 'Chemical sensitivity analysi'

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Published: 10 March 2023

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Journal articles on the topic "Chemical sensitivity analysi"

1

Saltelli, Andrea, Marco Ratto, Stefano Tarantola, and Francesca Campolongo. "Sensitivity Analysis for Chemical Models." Chemical Reviews 105, no. 7 (July 2005): 2811–28. http://dx.doi.org/10.1021/cr040659d.

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2

Larter, Raima, and Bruce L. Clarke. "Chemical reaction network sensitivity analysis." Journal of Chemical Physics 83, no. 1 (July 1985): 108–16. http://dx.doi.org/10.1063/1.449801.

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3

Turányi, Tamás. "Sensitivity analysis in chemical kinetics." International Journal of Chemical Kinetics 40, no. 11 (September 8, 2008): 685–86. http://dx.doi.org/10.1002/kin.20364.

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Zeliger, Harold I., Yaqin Pan, and William J. Rea. "Predicting co-morbidities in chemically sensitive individuals from exhaled breath analysis." Interdisciplinary Toxicology 5, no. 3 (August 1, 2012): 123–26. http://dx.doi.org/10.2478/v10102-012-0020-7.

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ABSTRACT The exhaled breath of more than four hundred patients who presented at the Environmental Health Center - Dallas with chemical sensitivity conditions were analyzed for the relative abundance of their breath chemical composition by gas chromatography and mass spectrometry for volatile and semi-volatile organic compounds. All presenting patients had no fewer than four and as many as eight co-morbid conditions. Surprisingly, almost all the exhaled breath analyses showed the presence of a preponderance of lipophilic aliphatic and aromatic hydrocarbons. The hydrophilic compounds present were almost entirely of natural origin, i.e. expected metabolites of foods. The lipophile, primarily C3 to C16 hydrocarbons and believed to have come from inhalation of polluted air, were, in all cases, present at concentrations far below those known to be toxic to humans, but caused sensitivity and signs of chemical overload. The co-morbid health effects observed are believed to be caused by the sequential absorption of lipophilic and hydrophilic chemicals; an initial absorption and retention of lipophile followed by a subsequent absorption of hydrophilic species facilitated by the retained lipophile to produce chemical mixtures that are toxic at very low levels. It is hypothesized that co-morbid conditions in chemically sensitive individuals can be predicted from analysis of their exhaled breath.
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Seferlis, P., and A. N. Hrymak. "Sensitivity analysis for chemical process optimization." Computers & Chemical Engineering 20, no. 10 (October 1996): 1177–200. http://dx.doi.org/10.1016/0098-1354(96)82074-6.

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6

Zak, Daniel E., Jörg Stelling, and Francis J. Doyle. "Sensitivity analysis of oscillatory (bio)chemical systems." Computers & Chemical Engineering 29, no. 3 (February 2005): 663–73. http://dx.doi.org/10.1016/j.compchemeng.2004.08.021.

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7

Nalewajski, Roman F. "Chemical reactivity concepts in charge sensitivity analysis." International Journal of Quantum Chemistry 56, no. 5 (December 5, 1995): 453–76. http://dx.doi.org/10.1002/qua.560560505.

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8

NARUKAWA, Tomohiro, Takayoshi KUROIWA, Izumi NARUSHIMA, and Koichi CHIBA. "Effect of the Chemical Species of Arsenic on Sensitivity in Graphite Furnace Atomic Absorption Spectrometry." Analytical Sciences 24, no. 3 (2008): 355–60. http://dx.doi.org/10.2116/analsci.24.355.

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Fishtik, Ilie, István Nagypál, and Ivan Gutman. "Sensitivity analysis of multiple chemical equilibria: Sensitivity coefficients and response equilibria." Journal of Chemical Physics 103, no. 17 (November 1995): 7545–55. http://dx.doi.org/10.1063/1.470271.

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Merritt, Michael, Alen Alexanderian, and Pierre A. Gremaud. "Multiscale Global Sensitivity Analysis for Stochastic Chemical Systems." Multiscale Modeling & Simulation 19, no. 1 (January 2021): 440–59. http://dx.doi.org/10.1137/20m1323989.

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Dissertations / Theses on the topic "Chemical sensitivity analysi"

1

Khan, Kamil Ahmad. "Sensitivity analysis for nonsmooth dynamic systems." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98156.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 369-377).
Nonsmoothness in dynamic process models can hinder conventional methods for simulation, sensitivity analysis, and optimization, and can be introduced, for example, by transitions in flow regime or thermodynamic phase, or through discrete changes in the operating mode of a process. While dedicated numerical methods exist for nonsmooth problems, these methods require generalized derivative information that can be difficult to furnish. This thesis presents some of the first automatable methods for computing these generalized derivatives. Firstly, Nesterov's lexicographic derivatives are shown to be elements of the plenary hull of Clarke's generalized Jacobian whenever they exist. Lexicographic derivatives thus provide useful local sensitivity information for use in numerical methods for nonsmooth problems. A vector forward mode of automatic differentiation is developed and implemented to evaluate lexicographic derivatives for finite compositions of simple lexicographically smooth functions, including the standard arithmetic operations, trigonometric functions, exp / log, piecewise differentiable functions such as the absolute-value function, and other nonsmooth functions such as the Euclidean norm. This method is accurate, automatable, and computationally inexpensive. Next, given a parametric ordinary differential equation (ODE) with a lexicographically smooth right-hand side function, parametric lexicographic derivatives of a solution trajectory are described in terms of the unique solution of a certain auxiliary ODE. A numerical method is developed and implemented to solve this auxiliary ODE, when the right-hand side function for the original ODE is a composition of absolute-value functions and analytic functions. Computationally tractable sufficient conditions are also presented for differentiability of the original ODE solution with respect to system parameters. Sufficient conditions are developed under which local inverse and implicit functions are lexicographically smooth. These conditions are combined with the results above to describe parametric lexicographic derivatives for certain hybrid discrete/ continuous systems, including some systems whose discrete mode trajectories change when parameters are perturbed. Lastly, to eliminate a particular source of nonsmoothness, a variant of McCormick's convex relaxation scheme is developed and implemented for use in global optimization methods. This variant produces twice-continuously differentiable convex underestimators for composite functions, while retaining the advantageous computational properties of McCormick's original scheme. Gradients are readily computed for these underestimators using automatic differentiation.
by Kamil Ahmad Khan.
Ph. D.
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2

Guinand, Ernique A. (Ernique Alberto) 1970. "Optimization and network sensitivity analysis for process retrofitting." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8744.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2001.
"February 2001."
Includes bibliographical references.
Retrofitting is the redesign of an operating chemical plant to find new configurations and optimal operating conditions. In the chemical industry, 60% of new capital investments in plants and equipment are retrofitting projects, while only 10% goes to building new plants. Investment in retrofitting amounted to $26 billion in 2000. Despite the importance of retrofitting, there are few methodologies for finding improved economic and environmental performance for continuous processes. This work proposes a systematic framework for the understanding of retrofitting of continuous chemical processes and develops a new methodology to support decision making in solving this problem. Successful retrofitting solutions derive from a balance of operational experience in the plant and the rigor of mathematical analysis. This balance is accomplished by proposing tools and algorithms that in the problem formulation, the analysis of the flowsheet, the synthesis of retrofitting options and the final decision, allow the decision maker to handle the complexity of the problem and focus on the truly critical aspects of the flowsheet. The proposed methodology structures the problem by defining a broad range of retrofitting objectives and alternatives. The initial step is the formulation of retrofitting as an optimization problem. This includes defining retrofitting goals and translating them into objective functions. A parameter optimization of the base case design determines the incentives and constraints for retrofitting. The analysis continues through a network optimization analogy. The representation of the flowsheet as a multicommodity network allows the use of a graph based algorithm to determine the cycles in the process and apply flow decomposition by techniques developed in this study. Flow decomposition determines the path and cycles by which commodities (chemicals) flow through the network. The focus on chemicals and their paths rather than unit operations avoids the distinction of process subsystems providing an integrated view of the flowsheet. The objective function is evaluated in terms of path and cycle flows. Using graphical and mathematical programming (sensitivity analysis) approaches, the synthesis stage identifies retrofitting opportunities that increase the favorable and limit the unfavorable paths and cycles. Once a set of appropriate retrofitting alternatives is identified. the decision stage proceeds through a systematic construction of the superstructure and the corresponding MINLP model. The procedure takes into account the implicit logic of the retrofit alternatives to reduce the space of decision variables. The methodology is completed with a framework to implement the outer approximation algorithm taking into account the characteristics of the retrofitting problem. Case studies illustrate the benefits of the different stages of the proposed retrofitting methodology: efficient solution algorithms, systematic ways to analyze and generate alternative plant configurations and ease in finding optimal designs and investment decisions. The new methodology is compatible with existing flowsheet simulation tools and optimization packages and can easily be applied to a wide range of practical problems.
Ernique A. Guinand.
Ph.D.
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3

Gomez, Jose Alberto Ph D. Massachusetts Institute of Technology. "Simulation, sensitivity analysis, and optimization of bioprocesses using dynamic flux balance analysis." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/117325.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 301-312).
Microbial communities are a critical component of natural ecosystems and industrial bioprocesses. In natural ecosystems, these communities can present abrupt and surprising responses to perturbations, which can have important consequences. For example, climate change can influence drastically the composition of microbial communities in the oceans, which in turn affects the entirety of the food chain, and changes in diet can affect drastically the composition of the human gut microbiome, making it stronger or more vulnerable to infection by pathogens. In industrial bioprocesses, engineers work with these communities to obtain desirable products such as biofuels, pharmaceuticals, and alcoholic beverages, or to achieve relevant environmental objectives such as wastewater treatment or carbon capture. Mathematical models of microbial communities are critical for the study of natural ecosystems and for the design and control of bioprocesses. Good mathematical models of microbial communities allow scientists to predict how robust an ecosystem is, how perturbed ecosystems can be remediated, how sensitive an ecosystem is with respect to specific perturbations, and in what ways and how fast it would react to environmental changes. Good mathematical models allow engineers to design better bioprocesses and control them to produce high-quality products that meet tight specifications. Despite the importance of microbial communities, mathematical models describing their behavior remain simplistic and only applicable to very simple and controlled bioprocesses. Therefore, the study of natural ecosystems and the design of complex bioprocesses is very challenging. As a result, the design of bioprocesses remains experiment-based, which is slow, expensive, and labor-intensive. With high throughput experiments large datasets are generated, but without reliable mathematical models critical links between the species in the community are often missed. The design of novel bioprocesses rely on informed guesses by scientists that can only be tested experimentally. The expenses incurred by these experiments can be difficult to justify. Predictive mathematical models of microbial communities can provide insights about the possible outcomes of novel bioprocesses and guide the experimental design, resulting in cheaper and faster bioprocess development. Most mathematical models describing microbial communities do not take into account the internal structure of the microorganisms. In recent years, new knowledge of the internal structures of these microorganisms has been generated using highthroughput DNA sequencing. Flux balance analysis (FBA) is a modeling framework that incorporates this new information into mathematical models of microbial communities. With FBA, growth and exchange flux predictions are made by solving linear programs (LPs) that are constructed based on the metabolic networks of the microorganisms. FBA can be combined with the mathematical models of dynamical biosystems, resulting in dynamic FBA (DFBA) models. DFBA models are difficult to simulate, sensitivity information is challenging to obtain, and reliable strategies to solve optimization problems with DFBA models embedded are lacking. Therefore, the use of DFBA models in science and industry remains very limited. This thesis makes DFBA simulation more accessible to scientists and engineers with DFBAlab, a fast, reliable, and efficient Matlab-based DFBA simulator. This simulator is used by more than a 100 academic users to simulate various processes such as chronic wound biofilms, gas fermentation in bubble column bioreactors, and beta-carotene production in microalgae. Also, novel combinations of microbial communities in raceway ponds have been studied. The performance of algal-yeast cocultures and more complex communities for biolipids production has been evaluated, gaining relevant insights that will soon be tested experimentally. These combinations could enable the production of lipids-rich biomass in locations far away from power plants and other concentrated CO 2 sources by utilizing lignocellulosic waste instead. Following reliable DFBA simulation, the mathematical theory required for sensitivity analysis of DFBA models, which happen to be nonsmooth, was developed. Methods to compute generalized derivative information for special compositions of functions, hierarchical LPs, and DFBA models were generated. Significant numerical challenges appeared during the sensitivity computation of DFBA models, some of which were resolved. Despite the challenges, sensitivity information for DFBA models was used to solve for the steady-state of a high-fidelity model of a bubble column bioreactor using nonsmooth equation-solving algorithms. Finally, local optimization strategies for different classes of problems with DFBA models embedded were generated. The classes of problems considered include parameter estimation and optimal batch, continuous steady-state, and continuous cyclic steady-state process design. These strategies were illustrated using toy metabolic networks as well as genome-scale metabolic networks. These optimization problems demonstrate the superior performance of optimizers when reliable sensitivity information is used, as opposed to approximate information obtained from finite differences. Future work includes the development of global optimization strategies, as well as increasing the robustness of the computation of sensitivities of DFBA models. Nevertheless, the application of DFBA models of microbial communities for the study of natural ecosystems and bioprocess design and control is closer to reality.
by Jose Alberto Gomez.
Ph. D.
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4

Gou, Tianyi. "Computational Tools for Chemical Data Assimilation with CMAQ." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31017.

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The Community Multiscale Air Quality (CMAQ) system is the Environmental Protection Agency's main modeling tool for atmospheric pollution studies. CMAQ-ADJ, the adjoint model of CMAQ, offers new analysis capabilities such as receptor-oriented sensitivity analysis and chemical data assimilation. This thesis presents the construction, validation, and properties of new adjoint modules in CMAQ, and illustrates their use in sensitivity analyses and data assimilation experiments. The new module of discrete adjoint of advection is implemented with the aid of automatic differentiation tool (TAMC) and is fully validated by comparing the adjoint sensitivities with finite difference values. In addition, adjoint sensitivity with respect to boundary conditions and boundary condition scaling factors are developed and validated in CMAQ. To investigate numerically the impact of the continuous and discrete advection adjoints on data assimilation, various four dimensional variational (4D-Var) data assimilation experiments are carried out with the 1D advection PDE, and with CMAQ advection using synthetic and real observation data. The results show that optimization procedure gives better estimates of the reference initial condition and converges faster when using gradients computed by the continuous adjoint approach. This counter-intuitive result is explained using the nonlinearity properties of the piecewise parabolic method (the numerical discretization of advection in CMAQ). Data assimilation experiments are carried out using real observation data. The simulation domain encompasses Texas and the simulation period is August 30 to September 1, 2006. Data assimilation is used to improve both initial and boundary conditions. These experiments further validate the tools developed in this thesis.
Master of Science
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5

Wilkins, Anna Katharina. "Sensitivity analysis of oscillating dynamical systems with applications to the mammalian circadian clock." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/42944.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2008.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 227-234).
The work presented in this thesis consists of two major parts. In Chapter 2, the theory for sensitivity analysis of oscillatory systems is developed and discussed. Several contributions are made, in particular in the precise definition of phase sensitivities and in the generalization of the theory to all types of autonomous oscillators. All methods rely on the solution of a boundary value problem, which identifies the periodic orbit. The choice of initial condition on the limit cycle has important consequences for phase sensitivity analysis, and its influence is quantified and discussed in detail. The results are exact and efficient to compute compared to existing partial methods. The theory is then applied to different models of the mammalian circadian clock system in the following chapters. First, different types of sensitivities in a pair of smaller models are analyzed. The models have slightly different architectures, with one having an additional negative feedback loop compared to the other. The differences in their behavior with respect to phases, the period and amplitude are discussed in the context of their network architecture. It is found that, contrary to previous assumptions in the literature, the additional negative feedback loop makes the model less "flexible" in at least one sense that was studied here. The theory was also applied to larger, more detailed models of the mammalian circadian clock, based on the original model of Forger and Peskin. Between the original model's publication in 2003 and the present time, several key advances were made in understanding the mechanistic detail of the mammalian circadian clock, and at least one additional clock gene was identified. These advances are incorporated in an extended model, which is then studied using sensitivity analysis. Period sensitivity analysis is performed first and it was found that only one negative feedback loop dominates the setting of the period.
(cont.) This was an interesting one-to-one correlation between one topological feature of the network and a single metric of network performance. This led to the question of whether the network architecture is modular, in the sense that each of the several feedback loops might be responsible for a separate network function. A function of particular interest is the ability to separately track "dawn" and "dusk", which is reported to be present in the circadian clock. The ability of the mammalian circadian clock to modify different relative phases --defined by different molecular events -- independently of the period was analyzed. If the model can maintain a perceived day -- defined by the time difference between two phases -- of different lengths, it can be argued that the model can track dawn and dusk separately. This capability is found in all mammalian clock models that were studied in this work, and furthermore, that a network-wide effort is needed to do so. Unlike in the case of the period sensitivities, relative phase sensitivities are distributed throughout several feedback loops. Interestingly, a small number of "key parameters" could be identified in the detailed models that consistently play important roles in the setting of period, amplitude and phases. It appears that most circadian clock features are under shared control by local parameters and by the more global "key parameters". Lastly, it is shown that sensitivity analysis, in particular period sensitivity analysis, can be very useful in parameter estimation for oscillatory systems biology models. In an approach termed "feature-based parameter fitting", the model's parameter values are selected based on their impact on the "features" of an oscillation (period, phases, amplitudes) rather than concentration data points. It is discussed how this approach changes the cost function during the parameter estimation optimization, and when it can be beneficial.
(cont.) A minimal model system from circadian biology, the Goodwin oscillator, is taken as an example. Overall, in this thesis it is shown that the contributions made to the theoretical understanding of sensitivities in oscillatory systems are relevant and useful in trying to answer questions that are currently open in circadian biology. In some cases, the theory could indicate exactly which experiments or detailed mechanistic studies are needed in order to perform meaningful mathematical analysis of the system as a whole. It is shown that, provided the biologically relevant quantities are analyzed, a network-wide understanding of the interplay between network function and topology can be gained and differences in performance between models of different size or topology can be quantified.
by Anna Katharina Wilkins.
Ph.D.
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6

Chen, Lu. "Computational Study of Turbulent Combustion Systems and Global Reactor Networks." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78804.

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A numerical study of turbulent combustion systems was pursued to examine different computational modeling techniques, namely computational fluid dynamics (CFD) and chemical reactor network (CRN) methods. Both methods have been studied and analyzed as individual techniques as well as a coupled approach to pursue better understandings of the mechanisms and interactions between turbulent flow and mixing, ignition behavior and pollutant formation. A thorough analysis and comparison of both turbulence models and chemistry representation methods was executed and simulations were compared and validated with experimental works. An extensive study of turbulence modeling methods, and the optimization of modeling techniques including turbulence intensity and computational domain size have been conducted. The final CFD model has demonstrated good predictive performance for different turbulent bluff-body flames. The NOx formation and the effects of fuel mixtures indicated that the addition of hydrogen to the fuel and non-flammable diluents like CO2 and H2O contribute to the reduction of NOx. The second part of the study focused on developing chemical models and methods that include the detailed gaseous reaction mechanism of GRI-Mech 3.0 but cost less computational time. A new chemical reactor network has been created based on the CFD results of combustion characteristics and flow fields. The proposed CRN has been validated with the temperature and species emission for different bluff-body flames and has shown the capability of being applied to general bluff-body systems. Specifically, the rate of production of NOx and the sensitivity analysis based on the CRN results helped to summarize the reduced reaction mechanism, which not only provided a promising method to generate representative reactions from hundreds of species and reactions in gaseous mechanism but also presented valuable information of the combustion mechanisms and NOx formation. Finally, the proposed reduced reaction mechanism from the sensitivity analysis was applied to the CFD simulations, which created a fully coupled process between CFD and CRN, and the results from the reduced reaction mechanism have shown good predictions compared with the probability density function method.
Ph. D.
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Holland, Troy Michael. "A Comprehensive Coal Conversion Model Extended to Oxy-Coal Conditions." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6525.

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CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work extends a comprehensive char conversion code (the Carbon Conversion Kinetics or CCK model), which treats surface oxidation and gasification reactions as well as processes such as film diffusion, pore diffusion, ash encapsulation, and annealing. In this work, the CCK model was thoroughly investigated with a global sensitivity analysis. The sensitivity analysis highlighted several submodels in the CCK code, which were updated with more realistic physics or otherwise extended to function in oxy-coal conditions. Improved submodels include a greatly extended annealing model, the swelling model, the mode of burning parameter, and the kinetic model, as well as the addition of the Chemical Percolation Devolatilization (CPD) model. The resultant Carbon Conversion Kinetics for oxy-coal combustion (CCK/oxy) model predictions were compared to oxy-coal data, and further compared to parallel data sets obtained at near conventional conditions.
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GOMES, MARCELO da S. "Determinacao de elementos metalicos em sedimentos da Baia do Almirantado, Ilha Rei George, Penisula Antartica." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10762.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Poduri, Shripriya Darshini. "THEORETICAL MODELING AND ANALYSIS OF AMMONIA GAS SENSING PROPERTIES OF VERTICALLY ALIGNED MULTIWALLED CARBON NANOTUBE RESISTIVE SENSORS AND ENHANCING THEIR SENSITIVITY." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/51.

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Vertically aligned Multiwalled Carbon Nanotubes (MWCNTs) were grown in the pores of Anodized Aluminum Oxide (AAO) templates and investigated for resistive sensor applications. High Sensitivity of 23% to low concentration (100 ppm) of ammonia was observed. An equivalent circuit model was developed to understand the current flow path in the resistive sensor. This helped us in achieving high sensitivities through amorphous carbon (a-C) layer thickness tailoring by employing post-growth processing techniques like plasma etching. A simulation model in MATLAB was developed to calculate the device resistance and the change in the sensitivity as a function of device parameters. The steady state response and transient response of the model to the number of ammonia molecules and its adsorption rate were studied. Effects of oxygen plasma, argon plasma and water plasma etch on thinning of the a-C layer were studied. In order to enhance the sensitivity, the top and bottom a-C layers were replaced by a more conductive metal layer. This also helped in understanding the current flow in the device and in the estimation of the resistivity of the a-C layer.
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Griffiths, Michael Lee. "Multivariate calibration for ICP-AES." Thesis, University of Plymouth, 2001. http://hdl.handle.net/10026.1/1942.

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The analysis of metals is now a major application area for ICP-AES, however, the technique suffers from both spectral and non-spectral interferences. This thesis details the application of univariate and multivariate calibration methods for the prediction of Pt, Pd, and Rh in acid-digested and of Au, Ag and Pd in fusion-digested autocatalyst samples. Of all the univariate calibration methods investigated matrix matching proved the most accurate method with relative root mean square errors (RRMSEs) for Pt, Pd and Rh of 2.4, 3.7, and 2.4 % for a series of synihelic lest solutions, and 12.0, 2.4, and 8.0 % for autocatalyst samples. In comparison, the multivariate calibration method (PLSl) yielded average relative errors for Pt, Pd, and RJi of 5.8, 3.0, and 3.5 % in the test solutions, and 32.0, 7.5, and 75.0 % in the autocatalyst samples. A variable selection procedure has been developed enabling multivariate models to be built using large parts of the atomic emission spectrum. The first stage identified and removed wavelengths whose PLS regression coefficients were equal to zero. The second stage ranked the remaining wavelengths according to their PLS regression coefficient and estimated standard error ratio. The algorithms were applied to the emission spectra for the determination of Pt, Pd and Rh in a synthetic matrix. For independent test samples variable selection gave RRMSEs of 5.3, 2.5 and 1.7 % for Pt, Pd and Rh respectively compared with 8.3, 7.0 and 3.1 % when using integrated atomic emission lines. Variable selection was then applied for the prediction of Au, Ag and Pd in independent test fusion digests. This resulted in RRMSEs of 74.2, 8.8 and 12.2 % for Au, Ag and Pd respectively which were comparable to those obtained using a more traditional univariate calibration approach. A preliminary study has shown that calibration drift can be corrected using Piecewise Direct Standardisation (PDS). The application of PDS to synthetic test samples analysed 10 days apart resulted in RRMSEs of 4.14, 3.03 and 1.88%, compared to 73.04, 44.39 and 28.06 % without correction, for Pt, Pd, and Rh respectively.
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Books on the topic "Chemical sensitivity analysi"

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Center, Lewis Research, ed. Decoupled direct method for sensitivity analysis in combustion kinetics. [Cleveland, Ohio]: National Aeronautics and Space Administration, 1987.

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Radhakrishnan, Krishnan. LSENS: The NASA Lewis kinetics and sensitivity analysis code. [Washington, D.C: National Aeronautics and Space Administration, Scientific and Technical Information Program Office ; aHanover, Md., 2000.

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A, Bittker David, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Program., eds. LSENS: A general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1994.

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Radhakrishnan, Krishnan. LSENS-a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. Washington D.C: National Aeronautics and Space Administration, 1994.

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Radhakrishnan, Krishnan. LSENS-a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. Washington D.C: National Aeronautics and Space Administration, 1994.

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Radhakrishnan, Krishnan. LSENS, a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. II. Code description and usage. Cleveland, Ohio: Lewis Research Center, 1994.

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Radhakrishnan, Krishnan. LSENS - a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. I. Theory and numerical solution procedures. Cleveland, Ohio: Lewis Research Center, 1994.

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Bittker, David A. LSENS, a General Chemical Kinetics and Sensitivity Analysis Code for homogeneous gas-phase reactions. III. Illustrative test problems. Cleveland: Lewis Research Center, 1994.

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LSENS, a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1994.

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LSENS, a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1994.

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Book chapters on the topic "Chemical sensitivity analysi"

1

Schönherr, Holger, and G. Julius Vancso. "Chemical Force Microscopy: Nanometer-Scale Surface Analysis with Chemical Sensitivity." In Scanning Probe Microscopies Beyond Imaging, 275–314. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527608516.ch10.

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Eno, Larry, and Herschel Rabitz. "Sensitivity Analysis and Its Role in Quantum Scattering Theory." In Advances in Chemical Physics, 177–226. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470142752.ch4.

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Balzarini, A., L. Honzak, G. Pirovano, G. M. Riva, and R. Zabkar. "WRF-Chem Model Sensitivity Analysis to Chemical Mechanism Choice." In Air Pollution Modeling and its Application XXIII, 557–61. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04379-1_92.

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Kiparissides, Costas, and Harilaos Mavridis. "Mathematical Modelling and Sensitivity Analysis of High Pressure Polyethylene Reactors." In Chemical Reactor Design and Technology, 759–77. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4400-8_21.

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Cowles, John R., Simon Daily, Stephen L. R. Ellison, William A. Hardcastle, and Carole Williams. "Experimental sensitivity analysis applied to sample preparation uncertainties: are ruggedness tests enough for measurement uncertainty estimates?" In Measurement Uncertainty in Chemical Analysis, 170–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-662-05173-3_31.

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Bolívar, Araceli, and Fernando Pérez-Rodríguez. "Application of Sensitivity Analysis Methods in Quantitative Risk Assessment." In Risk Assessment Methods for Biological and Chemical Hazards in Food, 191–210. Boca Raton : CRC Press, 2021.: CRC Press, 2020. http://dx.doi.org/10.1201/9780429083525-9.

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Wang, Lin, Bruce E. Dale, Lale Yurttas, and I. Goldwasser. "Cost Estimates and Sensitivity Analyses for the Ammonia Fiber Explosion Process." In Biotechnology for Fuels and Chemicals, 51–66. Totowa, NJ: Humana Press, 1998. http://dx.doi.org/10.1007/978-1-4612-1814-2_6.

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Nalewajski, Roman F. "Charge Sensitivity Analysis as Diagnostic Tool for Predicting Trends in Chemical Reactivity." In NATO ASI Series, 339–89. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4757-9975-0_15.

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Čapek, Pavel, and Andreas Seidel—Morgenstern. "Sensitivity Analysis of Multicomponent Mass Transport in Porous Solids Descibed by Partial Differential Equations." In Scientific Computing in Chemical Engineering II, 152–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-60185-9_16.

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Aebersold, Ruedi H., Heinz Nika, Gary D. Pipes, Richard E. H. Wettenhall, Stephen M. Clark, Leroy E. Hood, and Stephen B. H. Kent. "Accelerated High Sensitivity Sequence Analysis of Proteins and Peptides Immobilized on Chemically-modified Glass Fiber Discs." In Methods in Protein Sequence Analysis, 79–97. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-73834-0_11.

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Conference papers on the topic "Chemical sensitivity analysi"

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Dovichi, Norman J., Shade Wu, and Da Yung Chen. "High Sensitivity Fluorescence Detection of Biological Molecules." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.tha1.

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Fluorescein is a good fluorescent label for high sensitivity analysis. The molecule has high molar absorptivity, 5 × 104 L mol-1 cm-1 at 488 nm and near unit fluorescence quantum yield in the pH range of 8 to 10. Unfortunately, the molecule is not photostable undergoing irreversible photobleaching after absorbance of about 8,000 photons. Fluorescein may be used to label amino groups in amino acids, peptides, and proteins through the isothiocyanate derivative. Under basic conditions, the thiocarbamoyl derivative is formed, with relatively good stability. The reaction between amino acids and fluorescein isothiocyanate is first order in bod the concentration of amino acid and derivative, with an activation energy of about 16 kcal/mol. Under acidic conditions, the cyclic thiohydantoin derivative is formed, cleaving the terminal amino acid from proteins and peptides. This thiohydantoin derivative possesses greater photostability than the thiocarbamoyl derivative, decomposing after absorbance of about 12,000 photons. The thiocarbamoyl-thiohydantoin derivative series is the basis of an Edmon degradation scheme for protein sequencing. In addition to amino acid labeling, fluorescein may be used to label thiols through the bromobimane derivatives; a high sensitivity DNA analysis is based on this compound. Last, succinylfluorescein labeled chain terminating dideoxynucleotides are used in DNA sequencing, these molecules have similar spectral properties as fluorescein.
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Fister, J. C., L. M. Davis, S. C. Jacobson, and J. M. Ramsey. "High Sensitivity Detection on Microchips." In Laser Applications to Chemical and Environmental Analysis. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lwd.6.

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High efficiency separations coupled with rapid response times have been demonstrated on capillary electrophoresis devices micromachined on glass substrates. [1-3] Although detection of single organic dyes has been achieved with fluorescence detection in capillaries, [4] such detection limits have not yet been demonstrated in micromachined channels. Efficient, single molecule detection is desirable for many potential applications such as rapid DNA sequencing. The structure of microfabricated separation channels, however, does not readily facilitate a 90° fluorescence excitation/collection geometry which has been used to achieve high sensitivities in capillaries. [4] This optical geometry allows efficient spatial rejection of scattering at the capillary solution interfaces. Confocal detection in which the excitation source is introduced through the collection optics provides a means of achieving both high axial resolution and high collection efficiency.
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Mathies, Richard A., Konan Peck, and Lubert Stryer. "High-Sensitivity Single-Molecule Fluorescence Detection in Theory and Practice." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.tha2.

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The number of emitted photons that can be obtained from a fluorophore increases with the incident light intensity and the duration of illumination. However, saturation of the absorption transition and photodestruction place natural limits on the ultimate signal-to-noise ratio that can be obtained. Equations have been derived to describe the fluorescence-to-background-noise ratio in the presence of saturating light intensities and photodestruction.1 The fluorescence lifetime and the photodestruction quantum yield are the key parameters that determine the optimum light intensity and exposure time. To test this theory we have performed single molecule detection of phycoerythrin (PE). The laser power was selected to give a mean time between absorptions approximately equal to the fluorescence decay time. The transit time was selected to be nearly equal to the photodestruction time of ~600 μs. Under these conditions the photon count distribution function, the photon count autocorrelation function, and the concentration dependence clearly show that we are detecting bursts of fluorescence from individual fluorophores as they pass through the laser beam. A hard-wired version of this single-molecule detection system was used to measure the concentration of PE down to 10-15 M.2 This single-molecule counter is three orders-of-magnitude more sensitive than conventional fluorescence detection systems. The approach presented here should be useful in the optimization of fluorescence-detected DNA sequencing gels and in HPLC and capillary electrophoresis detectors.
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Schurig, D. A., R. E. Russo, and R. J. Silva. "Optimization of a Photoacoustic Cell Using a Finite Difference Model." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.tuc9.

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Photoacoustic spectrometers, for high-sensitivity solution absorption measurements, have been set up using pulsed laser illumination of cuvettes with piezoelectric transducers and gating amplifiers1. Such systems can attain higher sensitivity if the systems’ parameters are optimized and a few modifications are made. We developed and tested a model for describing the photoacoustic energy generation, propagation, and detection.
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Köllner, Malte, and Jürgen Wolfram. "How to find the limit of sensitivity for DNA-base identification by laser-induced fluorescence." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/laca.1992.mc3.

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To optimize laser-induced fluorescence experiments, we will undertake to find the limit of sensitivity - in numbers of molecules - for experiments that identify certain types of molecules, e.g. DNA-bases labelled with dyes. The experimental method to be considered is single photon counting or time-con-elated-single-photon-counting (TCSPC). The basic idea for the analysis is to look at the experiment from the data-analysis side, to find (a) an optimum statistical procedure for the analysis problem and (b) to find out what signal strength it needs.
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Havrilla, George J., and Christopher C. Carter. "Trace Copper Detection in High Salt Matrices by Laser Enhanced Ionization Spectrometry." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/laca.1987.tua2.

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The detection of trace levels of copper in high salt matrices, including matrices with low ionization potential elements such as alkali and alkaline earth elements and metal sulfate solutions, present unique challenges to conventional methods of analysis like inductively coupled plasma (ICP) atomic emission spectrometry and atomic absorption (AA) spectrometry. In each case the conventional method of analysis possesses sufficient sensitivity to perform the analysis at the 1 ng/mL level in aqueous solutions (1). However in matrices such as seawater and metal sulfate solutions chemical and spectroscopic interferences prevent these methods from achieving this level of sensitivity. This paper describes the use of laser enhanced ionization (LEI) spectrometry to detect copper in 0.5 M sulfate solutions and synthetic seawater at the 0.5 ng/mL level.
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Parks, J. E., L. J. Moore, M. T. Spaar, D. W. Beekman, and E. H. Taylor. "Ultratrace Solids Analyses Using Resonance Ionization Spectroscopy." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/laca.1987.tub1.

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Sputter initiated resonance ionization spectroscopy (SIRIS) is a new, ultrasensitive analytical technique for solids analysis, particularly in the fields of semiconductors, geophysics, biology, medicine, health physics, and basic science. SIRIS uses sputtering to atomize a solid sample and tunable dye lasers to selectively excite and ionize a selected element with the use of resonance ionization spectroscopy (RIS). The RIS process provides good sensitivity and allows interference-free measurements. The sensitivity is sufficiently high that analyses can be performed with a pulsed ion beam which does not sputter away more than an equivalent monolayer of the sample during an analysis. Thus, it is inherently a technique for surface analysis and for the analysis of very thin samples. For bulk analysis or for depth profiling, material can be removed by sputtering with a dc ion beam. The RIS technique is reviewed and the SIRIS technique is described along with the apparatus used at Atom Sciences. Applications for SIRIS are discussed and the results of measurements illustrating these applications are presented. For bulk analysis of gallium in silicon, a sensitivity of 2 ppb has been demonstrated. Depth profiles of silicon in gallium arsenide were made and recent results are presented. In a medical application, blood serum has been analyzed for trace amounts of copper and molybdenum. SIRIS allows the analysis of small, less than 0.1 ml, samples and is calibrated by the use of isotope dilution. Sensitivities of 20 pg are reported for molybdenum.
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Barnes, Michael D., William B. Whitten, and J. Michael Ramsey. "Single-Molecule Detection in Microdroplets." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/laca.1994.thd.1.

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Detection of single molecules in condensed phase with high signal-to-noise ratios is important for applications which involve detection of fluorescent tags such as DNA sequencing1, fluorescence immunoassay2, or hydrology.3 In addition, observation of photophysical phenomena unique to the interaction of a radiation field with an isolatedmolecule, such as photon antibunching,4 depends upon having such high sensitivity. As demonstrated by the experiments of Moerner5 and Orrit,6 very high sensitivity at the single molecule level can be achieved by probing "guest" molecules in solid hosts at cryogenic temperatures. However, practical applications requiring single molecule detection usually require measurements on liquid phase solutions at room temperature. These demands pose new problems such as solvent dependent quantum yield, finite photochemical lifetime (the number of absorption-emission cycles which occur before irreversible bleaching of fluorescence), and solvent Raman scattering and fluorescence.
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Johnston, Christopher R., Mark A. Bryant, and Jeanne E. Pemberton. "Surface Enhanced and Unenhanced Raman Scattering of Alkanethiols Adsorbed on Silver and Gold Surfaces." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.ma2.

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Raman spectroscopy has been demonstrated to be a powerful tool with which to probe the orientation of bonding of molecules on metal surfaces. Surface enhanced Raman scattering (SERS) has been successfully used for this purpose, but suffers from the requirement for considerable surface roughness in order for the ehancement to be realized. A more desirable approach is the acquisition of Raman spectra of molecules on smooth metal surfaces. This is accomplished in our laboratory with charge-coupled device (CCD) detection which provides adequate sensitivity for the observation of monolayers of organic molecules. This detector is coupled to a triple spectrometer and used with Ar+-pumped dye laser excitation between ca. 600 and 720 nm. Excitation in the red region of the spectrum is essential for enhancement on Au surfaces. The high quantum efficiencies of extended-red CCDs in this region provide excellent sensitivity for these measurements.
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Whitten, W. B., L. B. Koutny, T. G. Nolan, and J. M. Ramsey. "Low-Pressure Laser Spectroscopy with Flame Atomization." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/laca.1987.pdp16.

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The air-acetylene burner is commonly used as an atomization source for elemental analysis with various spectroscopic methods, ranging from flame emission to sophisticated laser-based techniques. The latter include laser-induced fluorescence, laser-enhanced ionization, polarization saturation spectroscopy, and degenerate four-wave mixing. All of these techniques exhibit excellent sensitivity for trace elements in water, typically in the parts per billion range or better. The spectral resolution, however, is limited to about 5 GHz because the spectral lines are broadened by collisions in the atmospheric pressure flame. We have developed a low-pressure interface that allows a hundred-fold improvement in resolution while retaining the sensitivity and convenience of flame atomization. We have tested the apparatus by studying the spectrum of the sodium D lines, using a type of saturation spectroscopy. We have been able to separate hyperfine transitions and crossover resonances with a resolution of better than 50 MHz. A recognizable hyperfine spectrum can be obtained with as little as 100 ppb of sodium.
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Reports on the topic "Chemical sensitivity analysi"

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Newby, Richard, and Dale Keairns. Chemical Looping Combustion Sensitivity Analyses: CLOU Concepts. Office of Scientific and Technical Information (OSTI), February 2018. http://dx.doi.org/10.2172/1886364.

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Newby, Richard, and Dale Keairns. Moving Bed Chemical Looping Combustion Fuel Reactor Modeling and Sensitivity Analysis. Office of Scientific and Technical Information (OSTI), February 2017. http://dx.doi.org/10.2172/1607680.

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Sutto, Thomas E. Prioritization and Sensitivity Analysis of the Inhalation/Ocular Hazard of Industrial Chemicals. Fort Belvoir, VA: Defense Technical Information Center, October 2011. http://dx.doi.org/10.21236/ada552552.

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Lehotay, Steven J., and Aviv Amirav. Fast, practical, and effective approach for the analysis of hazardous chemicals in the food supply. United States Department of Agriculture, April 2007. http://dx.doi.org/10.32747/2007.7695587.bard.

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Background to the topic: For food safety and security reasons, hundreds of pesticides, veterinary drugs, and environmental pollutants should be monitored in the food supply, but current methods are too time-consuming, laborious, and expensive. As a result, only a tiny fraction of the food is tested for a limited number of contaminants. Original proposal objectives: Our main original goal was to develop fast, practical, and effective new approaches for the analysis of hazardous chemicals in the food supply. We proposed to extend the QuEChERS approach to more pesticides, veterinary drugs and pollutants, further develop GC-MS and LC-MS with SMB and combine QuEChERS with GC-SMB-MS and LC-SMB-EI-MS to provide the “ultimate” approach for the analysis of hazardous chemicals in food. Major conclusions, solutions and achievements: The original QuEChERS method was validated for more than 200 pesticide residues in a variety of food crops. For the few basic pesticides for which the method gave lower recoveries, an extensive solvent suitability study was conducted, and a buffering modification was made to improve results for difficult analytes. Furthermore, evaluation of the QuEChERS approach for fatty matrices, including olives and its oil, was performed. The QuEChERS concept was also extended to acrylamide analysis in foods. Other advanced techniques to improve speed, ease, and effectiveness of chemical residue analysis were also successfully developed and/or evaluated, which include: a simple and inexpensive solvent-in-silicone-tube extraction approach for highly sensitive detection of nonpolar pesticides in GC; ruggedness testing of low-pressure GC-MS for 3-fold faster separations; optimization and extensive evaluation of analyte protectants in GC-MS; and use of prototypical commercial automated direct sample introduction devices for GC-MS. GC-MS with SMB was further developed and combined with the Varian 1200 GCMS/ MS system, resulting in a new type of GC-MS with advanced capabilities. Careful attention was given to the subject of GC-MS sensitivity and its LOD for difficult to analyze samples such as thermally labile pesticides or those with weak or no molecular ions, and record low LOD were demonstrated and discussed. The new approach of electron ionization LC-MS with SMB was developed, its key components of sample vaporization nozzle and flythrough ion source were improved and was evaluated with a range of samples, including carbamate pesticides. A new method and software based on IAA were developed and tested on a range of pesticides in agricultural matrices. This IAA method and software in combination with GC-MS and SMB provide extremely high confidence in sample identification. A new type of comprehensive GCxGC (based on flow modulation) was uniquely combined with GC-MS with SMB, and we demonstrated improved pesticide separation and identification in complex agricultural matrices using this novel approach. An improved device for aroma sample collection and introduction (SnifProbe) was further developed and favorably compared with SPME for coffee aroma sampling. Implications, both scientific and agricultural: We succeeded in achieving significant improvements in the analysis of hazardous chemicals in the food supply, from easy sample preparation approaches, through sample analysis by advanced new types of GC-MS and LCMS techniques, all the way to improved data analysis by lowering LOD and providing greater confidence in chemical identification. As a result, the combination of the QuEChERS approach, new and superior instrumentation, and the novel monitoring methods that were developed will enable vastly reduced time and cost of analysis, increased analytical scope, and a higher monitoring rate. This provides better enforcement, an added impetus for farmers to use good agricultural practices, improved food safety and security, increased trade, and greater consumer confidence in the food supply.
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Clausen, Jay, Richard Hark, Russ Harmon, John Plumer, Samuel Beal, and Meghan Bishop. A comparison of handheld field chemical sensors for soil characterization with a focus on LIBS. Engineer Research and Development Center (U.S.), February 2022. http://dx.doi.org/10.21079/11681/43282.

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Commercially available handheld chemical analyzers for forensic applications have been available for over a decade. Portable systems from multiple vendors can perform X-ray fluorescence (XRF) spectroscopy, Raman spectroscopy, Fourier transform infrared(FTIR) spectroscopy, and recently laser-induced breakdown spectroscopy (LIBS). Together, we have been exploring the development and potential applications of a multisensor system consisting of XRF, Raman, and LIBS for environmental characterization with a focus on soils from military ranges. Handheld sensors offer the potential to substantially increase sample throughput through the elimination of transport of samples back to the laboratory and labor-intensive sample preparation procedures. Further, these technologies have the capability for extremely rapid analysis, on the order of tens of seconds or less. We have compared and evaluated results from the analysis of several hundred soil samples using conventional laboratory bench top inductively coupled plasma atomic emission spectroscopy (ICP-AES) for metals evaluation and high-performance liquid chromatography (HPLC) and Raman spectroscopy for detection and characterization of energetic materials against handheld XRF, LIBS, and Raman analyzers. The soil samples contained antimony, copper, lead, tungsten, and zinc as well as energetic compounds such as 2,4,6-trinitrotoluene(TNT), hexahydro-1,3,5-triazine (RDX), nitroglycerine (NG), and dinitrotoluene isomers (DNT). Precision, accuracy, and sensitivity of the handheld field sensor technologies were compared against conventional laboratory instrumentation to determine their suitability for field characterization leading to decisional outcomes.
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Or, Etti, Tai-Ping Sun, Amnon Lichter, and Avichai Perl. Characterization and Manipulation of the Primary Components in Gibberellin Signaling in the Grape Berry. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7592649.bard.

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Seedless cultivars dominate the table grape industry. In these cultivars it is mandatory to apply gibberellin (GA) to stimulate berry development to a commercially acceptable size. These cultivars differ in their sensitivity to GA application, and it frequently results in adverse effects such as decreased bud fertility and increased fruit drop. Our long term goals are to (1) understand the molecular basis for the differential sensitivity and identify markers for selection of sensitive cultivars (2) to develop new strategies for targeted manipulation of the grape berry response to GA that will eliminate the need in GA application and the undesirable effects of GA on the vine, while maintaining its desirable effects on the berry. Both strategies are expected to reduce production cost and meet growing consumer demand for reduced use of chemicals. This approach relies on a comprehensive characterization of the central components in the GA signaling cascade in the berry. Several key components in the GA signaling pathway were identified in Arabidopsis and rice, including the GA receptors, GID1s, and a family of DELLA proteins that are the major negative regulators of the GA response. GA activates its response pathway by binding to GID1s, which then target DELLAs for degradation via interaction with SLY, a DELLA specific F-box protein. In grape, only one DELLA gene was characterized prior to this study, which plays a major role in inhibiting GA-promoted stem growth and GA-repressed floral induction but it does not regulate fruit growth. Therefore, we speculated that other DELLA family member(s) may control GA responses in berry, and their identification and manipulation may result in GA-independent berry growth. In the current study we isolated two additional VvDELLA family members, two VvGID1 genes and two VvSLY genes. Arabidopsis anti-AtRGA polyclonal antibodies recognized all three purified VvDELLA proteins, but its interaction with VvDELLA3 was weaker. Overexpression of the VvDELLAs, the VvGID1s, and the VvSLYs in the Arabidopsis mutants ga1-3/rga-24, gid1a-2/1c-2 and sly1-10, respectively, rescued the various mutant phenotypes. In vitro GAdependent physical interaction was shown between the VvDELLAs and the VvGID1s, and GAindependent interaction was shown between the VvDELLAs and VvSLYs. Interestingly, VvDELLA3 did not interact with VvGID1b. Together, the results indicate that the identified grape homologs serve as functional DELLA repressors, receptors and DELLA-interacting F-box proteins. Expression analyses revealed that (1) VvDELLA2 was expressed in all the analyzed tissues and was the most abundant (2) VvDELLA1 was low expressed in berries, confirming former study (3) Except in carpels and very young berries, VvDELLA3 levels were the lowest in most tissues. (4) Expression of both VvGID1s was detected in all the grape tissues, but VvGID1b transcript levels were significantly higher than VvGID1a. (5) In general, both VvDELLAs and VvGID1s transcripts levels increased as tissues aged. Unfertilized and recently fertilized carpels did not follow this trend, suggesting different regulatory mechanism of GA signaling in these stages. Characterization of the response to GA of various organs in three seedless cultivars revealed differential response of the berries and rachis. Interestingly, VvDELLA3 transcript levels in the GA-unresponsive berries of cv. Spring blush were significantly higher compared to their levels in the highly responsive berries of cv. Black finger. Assuming that VvDELLA2 and VvDELLA3 are regulating berry size, constructs carrying potential dominant mutations in each gene were created. Furthermore, constitutive silencing of these genes by mIR is underway, to reveal the effect of each gene on the berry phenotype.
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Honey authenticity: collaborative data sharing feasibility study. Food Standards Agency, January 2023. http://dx.doi.org/10.46756/sci.fsa.fbt231.

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According to the UN,1 there are more than 90 million managed beehives around the world producing about 1.9 million tonnes of honey worth more than £5 billion a year. That honey will then be packaged, as single origin or a blend of honey from different sources, and sold for consumption. Given the size of the market and the immense environmental benefits of beekeeping – three out of four crops depend on pollination by bees – it is an industry on which both livelihoods and lives depend. Target for adulteration As a labour-intensive, high-value expensive product with an often complex supply chain, honey is subject to internationally and nationally agreed definitions – and is a target for adulteration. Testing honey is therefore critical, but there is no single universal analytical method available which is capable of detecting all types of adulteration with adequate sensitivity. A variety of methods are used to detect honey adulteration, each test has strengths and weaknesses, and there are issues with interpretation. NMR analysis Testing for honey adulterated with added sugars may be based on analytical techniques using analytical tools, such as those using nuclear magnetic resonance spectroscopy (NMR). This is especially helpful in detecting certain types of adulteration, such as the addition of cane or beet sugars. Bees generally forage on plants that use the same photosynthetic pathway as beet sugars. This makes it difficult for traditional tests based on isotopic differences to provide effective results. The ‘chemical fingerprint’ provided by NMR is specific to the sample that has been tested and can be compared with the fingerprint from other sample results enabling the user to assess consistency. Reference databases Interpretation of results depends on comparison against a reference database of authenticated samples. The reference database needs to be representative of the variation that can occur, which includes differing beekeeping practices, origins, seasonality and variations in climate. Information is also needed on the collection of reference samples, curation of databases, interpretation and reporting of data. The nature of the reference databases is key to understanding how the results have been interpreted. However, these reference databases are owned by and commercially sensitive for the testing laboratories that have developed them. How can such data be shared in a trustworthy way between key stakeholders along the honey and analytical supply chain so that all parties can have confidence in honey authenticity test results? This research is looking into the implications of these hidden databases, especially in terms of the trust related to the validation certificates and the value that they have in the honey supply chain.
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