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Artykuły w czasopismach na temat "PH control system"
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van der Schoot, Bart H., Hans Voorthuyzen i Piet Bergveld. "The pH-static enzyme sensor: Design of the pH control system". Sensors and Actuators B: Chemical 1, nr 1-6 (styczeń 1990): 546–49. http://dx.doi.org/10.1016/0925-4005(90)80270-a.
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Ooi, W. X., A. W. Hermansson i C. H. Lim. "Model Predictive Control – Sliding Mode Control of a pH system". IOP Conference Series: Materials Science and Engineering 1257, nr 1 (1.10.2022): 012036. http://dx.doi.org/10.1088/1757-899x/1257/1/012036.
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Abstract This paper studies the feasibility of using discrete sliding mode controller (SMC) to achieve offset-free control of nonlinear processes in the presence of disturbances. The performance of the SMC is compared to a multiple model predictive controller (MMPC) studying the ability of set-point tracking using the pH system as a case study. The results presented from the comparison show that SMC can perform offset-free control of a pH system, with the major drawback being slow response as well as oscillation at some pH values. Finally, a design of a combination between MMPC and SMC (MMPC-SMC) is proposed, with MMPC carrying out basic control response while the SMC fulfils the role of eliminating the offset. However, the inaccurate reading in the MATLAB simulation model does not generate the expected results on the pH control. Therefore, the modification on the MATLAB models is required to achieve the improved control system on the offset-free behaviour for the set-point tracking.
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Safira, M. R., M. W. Lim i W. S. Chua. "Design of control system for water quality monitoring system for hydroponics application". IOP Conference Series: Materials Science and Engineering 1257, nr 1 (1.10.2022): 012027. http://dx.doi.org/10.1088/1757-899x/1257/1/012027.
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Abstract In hydroponic farming, optimal pH value is important to regulate nutrient availability for efficient plant growth. This study aims to design an autonomous pH monitoring and control system for maintaining an optimal pH range. The prototype was developed for data acquisition, data processing and data visualization to ensure that the measured nutritional solution parameters are within the specified range: temperature (18–35°C), pH (5.5–8.0), and dissolved oxygen level (>2 ppm). Data collected at sampling rate of 10 seconds utilising temperature sensor, pH sensor, and dissolved oxygen sensor were processed using a microcontroller on a Node-RED interface in a Raspberry Pi. The processed data were stored in InfluxDB before being displayed in Grafana. If the value exceeded the threshold, a Telegram alert was delivered to the end-user. The pH data were used to build a framework to control the pH levels within range. Two peristaltic pumps (DFRobot, DFR0523) were utilized to pump potassium hydroxide or phosphoric acid solution if the pH was out of range. The developed prototype was able to automatically control the pH within the optimum range in the nutrient solution, which will positively impact the nutrient adsorption and subsequent plant growth in a hydroponics system.
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Castanie-Cornet, Marie-Pierre, Thomas A. Penfound, Dean Smith, John F. Elliott i John W. Foster. "Control of Acid Resistance inEscherichia coli". Journal of Bacteriology 181, nr 11 (1.06.1999): 3525–35. http://dx.doi.org/10.1128/jb.181.11.3525-3535.1999.
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ABSTRACT Acid resistance (AR) in Escherichia coli is defined as the ability to withstand an acid challenge of pH 2.5 or less and is a trait generally restricted to stationary-phase cells. Earlier reports described three AR systems in E. coli. In the present study, the genetics and control of these three systems have been more clearly defined. Expression of the first AR system (designated the oxidative or glucose-repressed AR system) was previously shown to require the alternative sigma factor RpoS. Consistent with glucose repression, this system also proved to be dependent in many situations on the cyclic AMP receptor protein. The second AR system required the addition of arginine during pH 2.5 acid challenge, the structural gene for arginine decarboxylase (adiA), and the regulatorcysB, confirming earlier reports. The third AR system required glutamate for protection at pH 2.5, one of two genes encoding glutamate decarboxylase (gadA or gadB), and the gene encoding the putative glutamate:γ-aminobutyric acid antiporter (gadC). Only one of the two glutamate decarboxylases was needed for protection at pH 2.5. However, survival at pH 2 required both glutamate decarboxylase isozymes. Stationary phase and acid pH regulation of the gad genes proved separable. Stationary-phase induction of gadA and gadBrequired the alternative sigma factor ςS encoded byrpoS. However, acid induction of these enzymes, which was demonstrated to occur in exponential- and stationary-phase cells, proved to be ςS independent. Neither gad gene required the presence of volatile fatty acids for induction. The data also indicate that AR via the amino acid decarboxylase systems requires more than an inducible decarboxylase and antiporter. Another surprising finding was that the ςS-dependent oxidative system, originally thought to be acid induced, actually proved to be induced following entry into stationary phase regardless of the pH. However, an inhibitor produced at pH 8 somehow interferes with the activity of this system, giving the illusion of acid induction. The results also revealed that the AR system affording the most effective protection at pH 2 in complex medium (either Luria-Bertani broth or brain heart infusion broth plus 0.4% glucose) is the glutamate-dependent GAD system. Thus, E. coli possesses three overlapping acid survival systems whose various levels of control and differing requirements for activity ensure that at least one system will be available to protect the stationary-phase cell under naturally occurring acidic environments.
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KOBAYASHI, Yusuke, Yuichi NIIBORI i Tadashi CHIDA. "pH-control by Self-Organizing Fuzzy Controller System." Shigen-to-Sozai 108, nr 1 (1992): 7–12. http://dx.doi.org/10.2473/shigentosozai.108.7.
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Grancharova, A., i L. Kostov. "Model Predictive Control of a pH Maintaining System". Information Technologies and Control 11, nr 1 (1.03.2013): 14–20. http://dx.doi.org/10.2478/itc-2013-0003.
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Abstract In this paper the problem of optimal regulation of a pH maintaining system is considered, where the outputs are the pH value and the liquid level in the system and the control inputs are the flow rates of the base input flow and the output flow. The optimal regulation problem is formulated as a nonlinear model predictive control problem in the presence of constraints. Two cases are considered: 1) presence of box constraints only on the control inputs and 2) considering also constraints on the rate of change of the inputs.
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Palancar, María C., José M. Aragón i José S. Torrecilla. "pH-Control System Based on Artificial Neural Networks". Industrial & Engineering Chemistry Research 37, nr 7 (lipiec 1998): 2729–40. http://dx.doi.org/10.1021/ie970718w.
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Agustian, Indra, Bagus Imam Prayoga, Hendy Santosa, Novalio Daratha i Ruvita Faurina. "NFT Hydroponic Control Using Mamdani Fuzzy Inference System". Journal of Robotics and Control (JRC) 3, nr 3 (1.05.2022): 374–85. http://dx.doi.org/10.18196/jrc.v3i3.14714.
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The Nutrient Film Technique (NFT) method is one of the most popular hydroponic cultivation methods. This method has advantages such as easier maintenance, faster and optimal plant growth, better use of fertilizers, and less deposition. The disadvantages of NFT include the consumption of electrical power and the faster spread of disease. Therefore, NFT requires a good nutrient control and monitoring system to save electricity and achieve optimal growth and resistance to pests and diseases. In this study, a nutrient control was designed with indicators of pH and TDS levels and equipped with an Internet of Things (IoT) based monitoring system. The control system used is the Mamdani Fuzzy Inference System. The output of the system is the active time of the pH Up, pH Down, and AB Mix nutrient pumps, which aim to normalize the pH and TDS of nutrient liquids. The experimental results show that one to three control steps are needed to normalize pH. One control step has a response time of 60 seconds, and it can prevent pH Up and pH Down oscillations. As for TDS control, the prediction of AB mix pump active time works accurately, and TDS levels can be normalized in one control step. Overall, based on surface control, simulations, and real experimental data, it is indicated that the control system operates very well and can normalize pH and TDS to the desired normal standard.
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Qian, Yun, Tao Wu i Meng Fan Zhang. "Design and Implementation of Chemical Wastewater pH Control System". Applied Mechanics and Materials 700 (grudzień 2014): 447–50. http://dx.doi.org/10.4028/www.scientific.net/amm.700.447.
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pH parameter is one of the main factors influencing organic degradation in the sewage treatment, and the degradation of organic matter in biochemical treatment unit is the largest, the hydrolysis acidification processing unit is the second largest. When the water pH range of biochemical treatment unit is [6.8 7.2], organic degradation is in the largest degree. The pH range of neutralization unit must be based on a subsequent hydrolysis acidification treatment unit, in order to adjust the pH range dynamically. Finally we make wastewater treated by biochemical unit meet the pH standard, and make the organic matter degrade in the largest degree. We designed chemical wastewater pH intelligent control device based on MSP430F149 MCU. The application of this device shows that the method has high control accuracy, less drug consumption and has large organic matter degradation in the sewage treatment plant, etc.
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Klimenok, V. I., i O. S. Taramin. "A two-phase GI/PH/1 → ·/PH/1/0 system with losses". Automation and Remote Control 72, nr 5 (maj 2011): 1004–16. http://dx.doi.org/10.1134/s0005117911050080.
Pełny tekst źródłaRozprawy doktorskie na temat "PH control system"
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Favaro, Juliana. "Controle preditivo aplicado à planta piloto de neutralização de pH". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-16072013-170810/.
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Uma das técnicas de controle avançado que vem ganhando destaque no cenário econômico e ecológico, focando maior sustentabilidade e a otimização dos processos, é o controle preditivo, o qual já vem sendo aplicado em indústrias químicas e petroquímicas. Esta dissertação trata do desenvolvimento de um controle preditivo aplicado a uma planta piloto de neutralização de pH, presente no Laboratório de Controle de Processos Industriais da Escola Politécnica da Universidade de São Paulo. O desenvolvimento do projeto pode ser dividido em quatro etapas: implementação das malhas de controle regulatório, identificação dos sistemas, construção do controlador preditivo, aplicações e análises experimentais. Na primeira etapa foi necessário estudar o sistema em questão e implementar algumas malhas internas usando controladores PID. Na segunda etapa foi realizada a identificação do modelo da planta, ressaltando que pontos de operação e ajuste de parâmetros internos são determinantes para a modelagem. Já na terceira etapa desenvolveu-se um controlador preditivo, através de softwares auxiliares como o MATLAB e o IIT 800xA da ABB, que foram utilizados para o desenvolvimento e implementação do algoritmo de controle. Por fim, na última etapa, foi feita a análise e comparação dos resultados, quando se submete à planta a um controlador PID, quando aplicado um controlador preditivo em cascata com controladores PID e quando se utiliza apenas o controlador preditivo com ação direta nos atuadores.The predictive control is an advanced control technique which has gained evidence in the economic and ecological context because the search for sustainability and process optimization. This control has already been applied by the chemical and petrochemical industries. The purpose of this project is to develop a predictive controller which will be applied in a pH neutralization plant located in the Industrial Processes Control Laboratory at Polytechnic School of the University of São Paulo. The development of this project can be divided into four stages: implementation of regulatory control loops, identification of the system, construction of the predictive controller, applications and experimental analysis. The first step is necessary in order to study the plant and to implement some internal loops using PID controllers. In the second step, the identification process of the plant model will be done. It is important to note that operating points and internal parameter settings are very important for modeling. In the third stage, using the model obtained from the identification process, a predictive controller is built from auxiliary software such as MATLAB and IIT 800xA (by ABB), which will be used for the development and implementation of the control algorithm. Finally, the last step consists in collecting and analyzing the results of the pH neutralization plant. At this stage the responses of each controller will be compared: PID controller, MPC controller in cascade mode with PID and MPC controller acting directly on actuators.
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Alvarado, Christiam Segundo Morales. "Identificação e controle preditivo de uma planta-piloto de neutralização de pH". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-11072014-111203/.
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A identificação para controle é baseada especificamente na construção de modelos matemáticos a partir de dados experimentais, cuja finalidade é encontrar uma relação entre um conjunto de entradas e saídas de um processo dinâmico. Estes modelos são de fundamental importância para o projeto de controladores em processos industriais. No presente trabalho é realizada a identificação e o desenvolvimento do sistema de controle para uma planta piloto de neutralização de pH. O procedimento de identificação é baseado na coleta de dados reais do processo de neutralização de pH, operando em malha fechada. A estimativa dos modelos é realizada de duas formas: (1) estimar modelos que representem o comportamento de todo o sistema, incluindo os controladores PID do processo e (2) estimar modelos do processo com os dados coletados dos sinais de controle e as variáveis de saída do processo. Com os modelos do processo estimados projeta-se uma estratégia de controle MPC (Model Predictive Control), envolvendo dois esquemas de controle. O primeiro esquema calculará os set points ótimos que ingressarão nas malhas do processo. O segundo esquema calculará os sinais de controle ótimos que ingressarão diretamente no processo. O tipo de controlador MPC adotado é o QDMC (Quadratic Dynamic Matrix Control), permitindo restringir os sinais de entrada e saída do processo. A avaliação destes esquemas de controle é realizada mediante a mudança do set point das malhas do processo e a influência de perturbações. As perturbações são baseadas no aumento da vazão do ácido que ingressa no reator.Identification for control system is based specifically on the mathematical models construction from experimental data, whose aim is to find a relationship between a set of inputs and outputs of a dynamic process. These models are fundamentally important for the industrial processes controllers design. In this work is performed the identification and development of the control system for a pH neutralization pilot plant. The identification procedure is based on the real data collected from pH neutralization process, operating in closed loop. The models estimation is performed in two forms: (1) estimating models that represent all system behavior, including process PID controllers and (2) estimating process models with collecting data of the control signals and process output variables. The process models parameters estimation is performed with the algorithms studied in Chapter 4. With the estimated process models is a MPC (Model Predictive Control) control strategy was designed, creating two control schemes. First scheme will compute the optimal set points that will enter to the process-loops. The second scheme will compute the optimal control signals that will enter to the process. The type of MPC controller adopted is a QDMC (Quadratic Dynamic Matrix Control), allowing restriction of the input and output signals. The control schemes evaluation is performed by changing the set point of the process-loops and the disturbance influence. This disturbance is based on acid flow increased that enters the reactor.
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Obut, Salih. "Control Of Ph In Neutralization Reactor Of A Waste Water Treatment System Using Identification Reactor". Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606395/index.pdf.
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A typical wastewater effluent of a chemical process can contain several strong acids/bases, weak acids/bases as well as their salts. They must be neutralized before being discharged to the environment in order to protect aquatic life and human welfare. However, neutralization process is highly non&ndashlinear and has time&ndash
varying characteristics. Therefore, the control of pH is a challenging problem where advanced control strategies are often considered. In this study, the aim is to design a pH control system that will be capable of controlling the pH-value of a plant waste-water effluent stream having unknown acids with unknown concentrations using an on&ndash
line identification procedure. A Model Predictive Controller, MPC, and a Fuzzy Logic Controller, FLC, are designed and used in a laboratory scale pH neutralization system. The characteristic of the upstream flow is obtained by a small identification reactor which has ten times faster dynamics and which is working parallel to actual neutralization tank. In the control strategy, steady&ndash
state titration curve of the process stream is obtained using the data collected in terms of pH value from the response of the identification reactor to a pulse input in base flow rate and using the simulated response of the identification reactor for the same input. After obtaining the steady&ndash
state titration curve, it is used in the design of a Proportional&ndash
Integral, PI, and of an Adaptive Model Predictive Controller, AMPC. On the other hand, identification reactor is not used in the FLC scheme. The performances of the designed controllers are tested mainly for disturbance rejection, set&ndash
point tracking and robustness issues theoretically and experimentally. The superiority of the FLC is verified.
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David, William Whalley. "Intracellular pH and Na+ in heart cells during exposure to anisosmolar solutions : regulation of Na+-H+ exchange and Na+-K+ pump activity". Thesis, The University of Sydney, 1992. https://hdl.handle.net/2123/26486.
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Two important membrane transport processes involved in the regulation of intracellular pH (pH) and Na* activity (ave) are the plasmalemmal Na*-H* exchanger and Na*-K* pump. In several non-cardiac tissues exposure to a hyperosmolar or hypoosmolar (anisosmolar) extracellular milieu modulates the activity of the Na*-H* exchanger. The response of the Na*-K* pump to alterations of extracellular osmolarity is, however, largely unknown. In cardiac muscle the effects of changes in extracellular osmolarity and hence cell volume on the activity of the Na*-H* exchanger and Na*-K* pump has not been studied. Such a study is desirable since pH, and am are important determinants of contractility in cardiac muscle and because the myocardium may be exposed to an anisosmolar milieu in several clinical settings.
The studies described in this thesis examine the effect of shrinkage and swelling of cardiac tissue during exposure to anisosmolar solutions on the regulation of pH. and a'. by the sarcolemmal Na*-H* exchanger and Na*-K* pump.
Ion-selective microelectrodes were used to determine pH; and a'v. in guinea-pig ventricular muscle. Exposure of tissue to HEPES-buffered Tyrode's solution made hyperosmolar by the addition of 100 mM sucrose (418 mosM) produced an intracellular alkalinization of O.10 units and hyperpolarization of the membrane potential. When the Na*-H* exchanger was inhibited by 5-(N,N-dimethyl) amiloride (DMA) or by reducing extracellular Na* to 15 mM (choline substituted) exposure to hyperosmolar solution caused a small decrease in pH. The Na+-dependence and DMA-sensitivity of the intracellular alkalinization in hyperosmolar solution together with the demonstration of a DMA-sensitive rise in ax, during such exposure suggested that the sarcolemmal Na*-H* exchanger was activated by cell shrinkage in hyperosmolar solution. Further evidence for osmotic activation of the Na*-H* exchanger was obtained from experiments showing that the recovery of pH, from an intracellular acidosis, induced by brief exposure to NIL, CI, was faster in hyperosmolar than in isosmolar solution.
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Guner, Evren. "Adaptive Neuro Fuzzy Inference System Applications In Chemical Processes". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1252246/index.pdf.
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Neuro-Fuzzy systems are the systems that neural networks (NN) are incorporated in fuzzy systems, which can use knowledge automatically by learning algorithms of NNs. They can be viewed as a mixture of local experts. Adaptive Neuro-Fuzzy inference system (ANFIS) is one of the examples of Neuro Fuzzy systems in which a fuzzy system is implemented in the framework of adaptive networks. ANFIS constructs an input-output mapping based both on human knowledge (in the form of fuzzy rules) and on generated input-output data pairs.
Effective control for distillation systems, which are one of the important unit operations for chemical industries, can be easily designed with the known composition values. Online measurements of the compositions can be done using direct composition analyzers. However, online composition measurement is not feasible, since, these analyzers, like gas chromatographs, involve large measurement delays. As an alternative, compositions can be estimated from temperature measurements. Thus, an online estimator that utilizes temperature measurements can be used to infer the produced compositions. In this study, ANFIS estimators are designed to infer the top and bottom product compositions in a continuous distillation column and to infer the reflux drum compositions in a batch distillation column from the measurable tray temperatures. Designed estimator performances are further compared with the other types of estimators such as NN and Extended Kalman Filter (EKF).
In this study, ANFIS performance is also investigated in the adaptive Neuro-Fuzzy control of a pH system. ANFIS is used in specialized learning algorithm as a controller. Simple ANFIS structure is designed and implemented in adaptive closed loop control scheme. The performance of ANFIS controller is also compared with that of NN for the case under study.
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Tammia, Rasmus. "Modeling and Control of Lime Addition in a Flotation Process". Thesis, Linköpings universitet, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-139331.
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Flotation is an important and versatile mineral processing technique that is used to separate hydrophobic materials from hydrophilic. This technique makes it possible to mine complex ores that otherwise would have been regarded as uneconomic and non-beneficial. In this case flotation is used to separate copper from the unwanted gangue. The addition of lime is used to control the pH level in the flotation’s pulp, which governs the selectivity of the process, i.e. which minerals are recovered. Currently, fluctuating concentration grades of the produced metals have been observed in Boliden Aitik. Therefore, Boliden proposes a new control strategy which aims to maintain a constant ratio between the added lime and the incoming ore flow, but at the same time ensuring that the pH level is maintained within allowed limits. The aim of this thesis is to develop a model that captures the most essential dynamics of a process stage where lime is added, and then evaluate the suggested control strategy by studying suitable control structures. A linear model describing the system dynamics in a specific operating region is obtained by conducting step response experiments on the process. The model is then used to obtain a model describing the disturbances of the process, thereby yielding a complete model that describes the most important dynamics. The most promising control structure utilizes the concept of selective control, where a ratio controller is allowed to maintain a constant ratio as long as the pH level is within allowed boundaries. The pH level is maintained within the boundaries with upper and lower bound pH controllers that utilize the concept of an equivalent control objective (known as the strong acid equivalent) in order to achieve satisfying pH control. The results show that the control structure is able to maintain a constant ratio, and also ensure that the pH level is kept within the allowed limits. A cascade inspired pH ratio controller is also studied and evaluated. The results show that this pH ratio controller is only able to maintain a constant ratio as long as the incoming ore flow is constant. However, the outcomes also suggest that the concentration grades are either sensitive to variations in the ratio between added reagent and incoming ore flow, or that there is something else that causes them to vary.
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Boshoff, Gerhardus Marthinus. "Investigating a novel in vitro embryo culture system – The Walking Egg Affordable Assisted Reproductive Technology". Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/63049.
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Introduction: The desire to have a biological child transcends race, religion and
socio-economic status. However for those faced with infertility, the financial
resources needed to conceive are often not available. Current research in assisted
reproduction has gravitated towards cost reduction to address restricting financial
factors, without compromising quality of treatment. One such initiative is the
development of a low-cost embryo culture method by The Walking Egg foundation.
This method utilizes a standard chemical reaction and simple equipment to
equilibrate culture media pH and to regulate temperature; both aspects were
investigated in this study. An exploration into the insemination concentration to
achieve oocyte fertilization was also undertaken.
Methods: Quality control of temperature regulation on six different heating devices,
including a comparison of inter- and intra-variations was carried out. The utilization
of citric acid and bicarbonate of soda for carbon dioxide production, which
subsequently facilitate setting of pH values, was tested by injecting increasing citric
acid volumes (1.2 ml – 3.0 ml in 0.2 ml increments) into set volumes of bicarbonate
of soda. Further investigation evaluated gas production at various temperatures
(37°C, 25°C and 15°C), at increasing intervals (16 – 30 hours) of equilibration and
these were compared by measuring pH of the culture media. The influence of
altitude on pH was explored by repeating the chemical reaction experiment at five
different locations in South Africa. Furthermore, the addition of water to citric acid
before gas generation was explored.
The minimal insemination concentration needed for fertilization was determined by
the addition of decreasing numbers of spermatozoa to non-fertilized bisected
oocytes. The experiment was repeated with a selected sperm insemination number
in 1 ml or 50 μl culture media to compare the tested culture system with conventional
culture. Spermatozoa bound to the hemi-zonae were counted with the aid of an
inverted phase contrast microscope. Hemi-zonae with bound sperm were also
stained with ethidium homodimer and evaluated using a confocal laser-scanning
microscopy system. After removal of hemi-zonae, the spermatozoa in culture were
isolated for deoxyribonucleic acid fragmentation analyses and reactive oxygen species presence in the culture media was measured. Additionally, reactive oxygen
species generation in simulated culture was measured over time.
Results: All the equipment tested bar one, the warming oven, proved useable with
the simplified Walking Egg in vitro fertilization culture system. By decreasing the
citric acid volumes, it was indicated that 1.8 ml citric acid, diluted with 1.2 ml water, is
the optimal volume to facilitate the required culture media pH. Omitting the water
dilution from citric acid volumes affected the culture media pH adversely, however
reducing the temperature during gas equilibration did not. A change in altitude had
no effect on culture media pH.
Lower insemination numbers resulted in decreased sperm binding, with
2 x 103 motile sperm insemination providing the lowest number to still obtain
sufficient sperm–zona binding (≥20 sperm bound). Incubation in 1 ml vs. 200 μl
culture media indicated decrease in sperm bound. Sperm deoxyribonucleic acid
fragmentation and the presence of reactive oxygen species in the culture media were
similar in both the test and control groups. A comparison over time revealed less
reactive oxygen species in 1 ml culture media, from the simplified Walking Egg in
vitro fertilization culture system after three days of culture, than 200 μl culture media
drops under oil, from conventional culture after 18 hours, however the results were
not statistically significant.
Discussion: Purpose-made heating devices provide superior stabilization of culture
media temperature. When selecting a heating device, intra-variations should be
considered. Culture media can be manipulated to the required pH by carbon dioxide
production, with meticulous attention paid to the citric acid volumes used. However,
if gas generation is performed at room temperature, equilibration time must be
increased. In conventional culture, the minimum insemination number can be reduced to 2 x 103
motile sperm. Due to lower binding of sperm in large volumes of culture media,
2 – 5 x 103 motile sperm should be considered for the simplified culture system,
depending on a holistic consideration of all sperm parameters. Extended culture for
at least three days with the simplified culture system can be performed without increasing reactive oxygen species present in culture media. Further research of this
novel culture method should include the application of the culture method in a South
African environment.Dissertation (MSc)--University of Pretoria, 2017.
Obstetrics and Gynaecology
MSc
Unrestricted
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Larsson, Jonathan. "PH-MÄTNING I PAPPERSPRODUKTION : En studie i optimeringar av elektriska mätsystem". Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184577.
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Den fundamentala principen för tillverkning av papper är inte en särskilt komplicerad sådan. Men för att pappret skall erhålla specifika egenskaper blir processen alltmer komplicerad. Bland annat tillsätts olika typer av kemikalier och processen övervakas ständigt av olika system. Ett av dessa system mäter pH-halten i pappersmassan. Mätsystemet är dock utsatt för frekventa mätfel vilket medför en felaktig dosering av den koldioxid som används för att sänka pH-värdet. Detta kan slutligen ha negativ påverkan på papprets egenskaper. Syftet bakom arbetet är att mätsystemet ska bidra till en jämn reglering av pH och därigenom garantera jämn papperskvalitet. För detta arbete har en frågeställning och ett antal mål och delmål etablerats. De övergripande målen omfattar att etablera en statistisk modell över mätfel och beräkna eventuella ekonomiska besparingar. För att uppfylla mål och besvara frågeställningen måste en grunduppfattning byggas uppför berörda delar av tillverkningsprocessen, pH-värdets påverkan i processen, pH-sensorns mätprincip, mätsystemets utformning och rutiner som berör mätsystemet. Med denna grund undersöks uppkomsten av mätfel för de sex mätpunkterna. Detta utförs med två tillvägagångssätt: Sammanställning av lagrade historiska data och sammanställningar avprovtagningar utförda under kontrollerade förhållanden. De aspekter som undersöks är magnitud, frekvens och hur dessa förhåller sig till olika processrelaterade värden. En kalkyl för kostnader berörande mätsystemet upprättas även. Denna omfattar aktuella kostnader för koldioxid och underhåll. I resultatet presenteras en statistisk modell över mätfel, uppdelat på historiska och i närtid. Den historiska modellen visar, för samtliga behandlade positioner, en medelavvikelse på <0,3 pH-enheter. Den min- och maximala avvikelsen kan däremot uppgå till >0,8 pH-enheter. Modellen för närtid visar på kraftiga avvikelser för fyra av de sex behandlade systempositionerna, som relaterar både till papperskvalitet och ytvikt. Denna statistiska modell används sedan för att beräkna möjliga besparingar. Här påvisades att viss besparing fanns, både för koldioxid och för underhållskostnader. Slutsatsen för detta arbete är att ett mätfel existerar för majoriteten av de behandlade positionerna. Det har även kunnat påvisas ett samband med de undersökta processrelaterade aspekterna, men resultatet kan inte garanteras fullständigt. Med detta kunde även en möjlig besparing av koldioxid uppskattas vid bättre mätnoggrannhet. Besparingen uppgick till c:a 200 tkr, vilket i jämförelse med företagets omsättning endast utgör 0,075‰ av denna.The fundamental principle for manufacturing paper is not a complicated one. However, for the paper to acquire specific properties, the process becomes increasingly complicated.Among other things, different chemicals are added, and the process is continuouslymonitored by various systems. One of these systems measures the pH-level of the pulp. This system is however constantly affected by measuring errors, which in turn leads to the incorrect dosage of the carbon dioxide used to lower the pH-level. This could in turn have a negative impact on the properties of the final paper. The underlaying purpose of this project is for the measuring system to ensure an even regulation of pH and therethrough guarantee an even paper quality. For this project, several question at issue, goals and subgoals have been established. The general goals cover establishing a statistical model for the error and estimate possible economical savings. To fulfil the goals and answer the questions at issue, firstly a basic understanding must be established for: concerned parts of the manufacturing process, the effect pH-level has on the process, the measuring principle of the pH-sensor, the design of the measuring systemand the routines concerning the measuring system. With this basis, the occurrence of measuring error is examined for the six measuring points. This is accomplished with two methods: The compilation of historical data and the compilation of manual measurementsexecuted under controlled conditions. The aspects examined are magnitude, frequency and the relation to process related values. Finally, a calculation for costs regarding the measuring system was established. This includes current carbon dioxide and maintenance costs. The result presents a statistical model for the measuring error, divided into historical and near time. The historical model shows that for all the addressed positions, a mean deviation occurred <0.3 pH-units. However, the minimum and maximum deviation could reach >0.8 pH-units. The model for near time shows significant deviations for four out of the six covered positions, which in turn shows relations to both paper quality and surface weight. With this statistical model possible savings were calculated. This in turn showed the possibility of savings for both carbon dioxide and maintenance. The conclusion for this project is the existence of a measuring error. Also, a connection between this and the process related aspects could be established. Although, the result cannot be completely guarantied. With this, possible savings through better accuracy could be estimated. Though, these were only in the size of 0.075‰ of the company’s total revenue.
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Alvarado, Christiam Segundo Morales. "Estudo e implementação de métodos de validação de modelos matemáticos aplicados no desenvolvimento de sistemas de controle de processos industriais". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-05092017-092437/.
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A validação de modelos lineares é uma etapa importante em um projeto de Identificação de Sistemas, pois a escolha correta do modelo para representar a maior parte da dinâmica do processo, dentro de um número finito de técnicas de identificação e em torno de um ponto de operação, permite o sucesso no desenvolvimento de controladores preditivos e de controladores robustos. Por tal razão, o objetivo principal desta Tese é o desenvolvimento de um método de validação de modelos lineares, tendo como ferramentas de avaliação os métodos estatísticos, avaliações dinâmicas e análise da robustez do modelo. O componente principal do sistema de validação de modelos lineares proposto é o desenvolvimento de um sistema fuzzy para análise dos resultados obtidos pelas ferramentas utilizadas na etapa de validação. O projeto de Identificação de Sistemas é baseado em dados reais de operação de uma Planta-Piloto de Neutralização de pH, localizada no Laboratório de Controle de Processos Industriais da Escola Politécnica da USP. Para verificar o resultado da validação, todos os modelos são testados em um controlador preditivo do tipo QDMC (Quadratic Dynamic Matrix Control) para seguir uma trajetória de referência. Os critérios utilizados para avaliar o desempenho do controlador QDMC, para cada modelo utilizado, foram a velocidade de resposta do controlador e o índice da mínima variabilidade da variável de processo. Os resultados mostram que a confiabilidade do sistema de validação projetado para malhas com baixa e alta não-linearidade em um processo real, foram de 85,71% e 50%, respectivamente, com relação aos índices de desempenho obtidos pelo controlador QDMC.Linear model validation is the most important stage in System Identification Project because, the model correct selection to represent the most of process dynamic allows the success in the development of predictive and robust controllers, within identification technique finite number and around the operation point. For this reason, the development of linear model validation methods is the main objective in this Thesis, taking as a tools of assessing the statistical, dynamic and robustness methods. Fuzzy system is the main component of model linear validation system proposed to analyze the results obtained by the tools used in validation stage. System Identification project is performed through operation real data of a pH neutralization pilot plant, located at the Industrial Process Control Laboratory, IPCL, of the Escola Politécnica of the University of São Paulo, Brazil. In order to verify the validation results, all modes are used in QDMC type predictive controller, to follow a set point tracking. The criterions used to assess the QDMC controller performance were the speed response and the process variable minimum variance index, for each model used. The results show that the validation system reliability were 85.71% and 50% projected for low and high non-linearity in a real process, respectively, linking to the performance indexes obtained by the QDMC controller.
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Quachio, Raphael. "Análise do algoritmo PLS-PH para identificação de sistemas". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-29062012-145724/.
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O presente texto tem por objetivo avaliar diferentes aplicações do algoritmo PLS-PH (Partial Least Squares Prediction Horizon), desenvolvido por (LAURI et al., 2010) para a identificação de sistemas, com o objetivo de desenvolvimento de controladores MPC. Desta maneira, é avaliada a capacidade do algoritmo gerar modelos lineares para realizar predições múltiplos passos à frente, para sistemas SISO e MIMO, com dados coletados em malha fechada. É também avaliada a capacidade do algoritmo de identificar modelos não-lineares baseados na estrutura NARX polinomial.The objective of this work consists in evaluating different applications of the PLS-PH (Partial Least Squares Prediction Horizon) algorithm, developed by (LAURI et al., 2010), in order to identify models for MPC controllers. The algorithms capacity of producing linear models capable of performing multiple steps-ahead prediction for both SISO and MIMO systems, with data collected in closed-loop. The algorithms capability of identifying non-linear models with the NARX polynomial structure is also evaluated.
Książki na temat "PH control system"
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Kalafatis, Alexandros D. Identification and control of Wiener-type nonlinear systems with applications to pH processes. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1997.
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Dalbeth, Nicola. Epidemiology. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198748311.003.0003.
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The aetiopathogenesis of gout is initiated by urate overproduction and uric acid under-excretion, leading to hyperuricaemia. Foods such as seafood, red meat, beer, and sugar-sweetened beverages contribute to overproduction. Under-excretion is mediated by renal and gut uric acid transporters such as SLC2A9, ABCG2, and URAT1. In hyperurcaemia, there is formation of monosodium urate (MSU) crystals in joints, with acute gouty arthritis mediated by the innate immune system occurring in response to these crystals. Factors such as urate concentration, proteins present in synovial fluid, temperature, and pH control crystal nucleation and growth. Activation of the inflammasome by MSU crystals and production of interleukin-1ß is central to acute gouty arthritis. Advanced gout occurs when there is persistent gouty arthritis and tophus with the tophus being an organized immune tissue response to MSU crystals that involves both innate and adaptive immune cells. Progression through the gout checkpoints (hyperuricaemia, MSU crystal formation, and immune response) is governed by inherited genetic variants, lifetime environmental exposures, and their interaction.
Części książek na temat "PH control system"
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Yano, Takuo, i Yoshinori Nishizawa. "A Simple Automatic Control System of Ph and Do". W Animal Cell Technology: Basic & Applied Aspects, 295–302. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2844-5_41.
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Lee, Peter L. "An Industrial Application of Reference System Synthesis/Generic Model Control: Wastewater pH Control". W Nonlinear Process Control, 43–65. London: Springer London, 1993. http://dx.doi.org/10.1007/978-1-4471-2079-7_3.
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Sunori, Sandeep Kumar, Pushpa Bhakuni Negi, Amit Mittal, Bhawana, Pratul Goyal i Pradeep Kumar Juneja. "Soft Computing-Based Optimization of pH Control System of Sugar Mill". W Expert Clouds and Applications, 271–81. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2126-0_24.
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Herriyance, Poltak Sihombing i Rido Rivaldo. "Development of an Automatic Control System for Controlling of Soil pH Using a Microcontroller". W Advances in Intelligent Systems and Computing, 107–19. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4062-6_10.
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Aizawa, Peter, Charlotte Benemar, Cecilia Wingenblixt, Kristina Martinelle i Elisabeth Lindner. "Conventional Stirred Bioreactor Control System for Monitoring and Controlling pH and DO in a Wave Bioreactor". W Cells and Culture, 823–28. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-3419-9_144.
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Khatri, Narendra, Abhishek Sharma, Kamal Kishore Khatri i Ganesh D. Sharma. "An IoT-Based Innovative Real-Time pH Monitoring and Control of Municipal Wastewater for Agriculture and Gardening". W Proceedings of First International Conference on Smart System, Innovations and Computing, 353–62. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-5828-8_34.
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Eck, Mathilde, Oliver Körner i M. Haïssam Jijakli. "Nutrient Cycling in Aquaponics Systems". W Aquaponics Food Production Systems, 231–46. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-15943-6_9.
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AbstractIn aquaponics, nutrients originate mainly from the fish feed and water inputs in the system. A substantial part of the feed is ingested by the fish and either used for growth and metabolism or excreted as soluble and solid faeces, while the rest of any uneaten feed decays in the tanks. While the soluble excretions are readily available for the plants, the solid faeces need to be mineralised by microorganisms in order for its nutrient content to be available for plant uptake. It is thus more challenging to control the available nutrient concentrations in aquaponics than in hydroponics. Furthermore, many factors, amongst others pH, temperature and light intensity, influence the nutrient availability and plant uptake. Until today, most studies have focused on the nitrogen and phosphorus cycles. However, to ensure good crop yields, it is necessary to provide the plants with sufficient levels of all key nutrients. It is therefore essential to better understand and control nutrient cycles in aquaponics.
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Tripetchkul, Sudarut, Michio Tonokawa, Ayaaki Ishizaki, Zhongping Shi i Kazuyuki Shimizu. "Anaerobic Continuous Ethanol Fermentation using a Computer-Coupled Medium Feeding System Which has DDC Control pH of the Culture Broth". W Developments in Food Engineering, 561–63. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2674-2_180.
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Guern, Jean, Yves Mathieu, Geneviève Ephritikhine, Cornelia I. Ullrich-Eberius, Ulrich Lüttge, Maria-Térésa Marré i Erasmo Marré. "Intracellular pH Modifications Linked to the Activity of the Ferricyanide Driven Activity of the Plasmalemma Redox System in Elodea densa Leaves, Acer pseudoplatanus and Catharanthus roseus Cells". W Plasma Membrane Oxidoreductases in Control of Animal and Plant Growth, 412. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4684-8029-0_55.
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Tofail, Syed A. M. "A Dynamically Degradable Surface: Can We ‘Fool’ Bacteria to Delay Biofouling in Urinary Stents?" W Urinary Stents, 187–95. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_16.
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AbstractHuman body has evolved multiple strategies such as the development of a complex immune system and procurement of commensal microorganisms to deal with detrimental invasion by microbes. Despite this, biofilms pose an extremely difficult mechanism for humans to cope with infections caused by both pathogenic and opportunistically pathogenic microorganisms. Biofilms on urinary stents can lead to patient-discomfort, urinary tract infection and bacteriuria, antimicrobial resistance, stent fouling (encrustation) and obstruction. Currently, biofilm prevention and treatment in ureteral stents are carried out using a ‘static’ coating of the stent with heparin or a pH control-buffer. They increase patency but still becomes colonised by bacteria leading to biofilms. In this chapter we outline a patent-pending first-principle design strategy for a stent-coating stents that has the potential of increasing the patency by manifold and, at will. This strategy involves delaying biofouling with a ‘dynamically degradable surface’ and will be described in this chapter.
Streszczenia konferencji na temat "PH control system"
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Campbell, I., D. Uduehi, A. Ordys i G. van der Molen. "pH process control system benchmarking". W Proceedings of American Control Conference. IEEE, 2001. http://dx.doi.org/10.1109/acc.2001.945658.
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Mercader, Pedro, Kristian Soltesz i Alfonso Banos. "Autotuning of an in-line pH control system". W 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA). IEEE, 2016. http://dx.doi.org/10.1109/etfa.2016.7733588.
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Hermansson, A. W., S. Syafiiey i S. B. Mohd Noorz. "Multiple model predictive control of nonlinear pH neutralization system". W EM). IEEE, 2010. http://dx.doi.org/10.1109/ieem.2010.5674469.
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He, Baoxiang, Kaibin Chu, Guirong Lu, Shuyue Chen i Peng Wang. "A PH complex control system built-in correction factor". W 2010 Sixth International Conference on Natural Computation (ICNC). IEEE, 2010. http://dx.doi.org/10.1109/icnc.2010.5583159.
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Singh, Parikshit Kishor, Surekha Bhanot i Hare Krishna Mohanta. "Optimized adaptive neuro-fuzzy inference system for pH control". W 2013 International Conference on Advanced Electronic Systems (ICAES). IEEE, 2013. http://dx.doi.org/10.1109/icaes.2013.6659349.
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Triantino, Septiandi Budi, Anggraini Mulwinda, Arimaz Hangga, Aryo Baskoro Utomo, Nur Azis Salim i Alim Muanifatin Nisa. "Control System of Nutrient Solution pH Using Fuzzy Logic for Hydroponics System". W 2022 9th International Conference on Information Technology, Computer, and Electrical Engineering (ICITACEE). IEEE, 2022. http://dx.doi.org/10.1109/icitacee55701.2022.9924108.
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Daffa Fadillah, Muhammad, Nanang Ismail, Rina Mardiati i Ading Kusdiana. "Fuzzy Logic-Based Control System to Maintain pH in Aquaponic". W 2021 7th International Conference on Wireless and Telematics (ICWT). IEEE, 2021. http://dx.doi.org/10.1109/icwt52862.2021.9678404.
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Liu, Quanbo, Xiaoli Li, Kang Wang i Yang Li. "CPS-based Slurry pH Control in Wet Flue Gas Desulfurization System". W 2020 Chinese Control And Decision Conference (CCDC). IEEE, 2020. http://dx.doi.org/10.1109/ccdc49329.2020.9164744.
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Hermansson, A. W., i S. Syafiie. "Control of pH neutralization system using nonlinear model predictive control with I-controller". W 2014 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM). IEEE, 2014. http://dx.doi.org/10.1109/ieem.2014.7058759.
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Tong, Chen, Di Peng i Yang Jing. "Study on series repairable system reliability model based on PH distribution". W 2017 29th Chinese Control And Decision Conference (CCDC). IEEE, 2017. http://dx.doi.org/10.1109/ccdc.2017.7978933.
Pełny tekst źródłaRaporty organizacyjne na temat "PH control system"
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Montville, Thomas J., i Roni Shapira. Molecular Engineering of Pediocin A to Establish Structure/Function Relationships for Mechanistic Control of Foodborne Pathogens. United States Department of Agriculture, sierpień 1993. http://dx.doi.org/10.32747/1993.7568088.bard.
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This project relates the structure of the bacteriocin molecule (which is genetically determined) to its antimicrobial function. We have sequenced the 19,542 bp pediocin plasmid pMD136 and developed a genetic transfer system for pediococci. The pediocin A operon is complex, containing putative structural, immunity, processing, and transport genes. The deduced sequence of the pediocin A molecule contains 44 amino acids and has a predicted PI of 9.45. Mechanistic studies compared the interaction of pediocin PA-1 and nisin with Listeria monocytgenes cells and model lipid systems. While significant nisin-induced intracellular ATP depletion is caused by efflux, pediocin-induced depletion is caused exclusively by hydrolysis. Liposomes derived from L. monocytogenes phospholipids were used to study the physical chemistry of pediocin and nisin interactions with lipids. Their different pH optima are the results of different specific ionizable amino acids. We generated a predicted 3-D structural model for pediocin PA-1 and used a variety of mutant pediocins to demonstrate that the "positive patch" at residues 11 and 12 (and not the YGNGV consensus sequence) is responsible for the binding step of pediocin action. This structure/function understanding gained here provides necessary prerequisites to the more efficacious use of bacteriocins to control foodborne pathogens.
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Ron, Eliora, i Eugene Eugene Nester. Global functional genomics of plant cell transformation by agrobacterium. United States Department of Agriculture, marzec 2009. http://dx.doi.org/10.32747/2009.7695860.bard.
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The aim of this study was to carry out a global functional genomics analysis of plant cell transformation by Agrobacterium in order to define and characterize the physiology of Agrobacterium in the acidic environment of a wounded plant. We planed to study the proteome and transcriptome of Agrobacterium in response to a change in pH, from 7.2 to 5.5 and identify genes and circuits directly involved in this change. Bacteria-plant interactions involve a large number of global regulatory systems, which are essential for protection against new stressful conditions. The interaction of bacteria with their hosts has been previously studied by genetic-physiological methods. We wanted to make use of the new capabilities to study these interactions on a global scale, using transcription analysis (transcriptomics, microarrays) and proteomics (2D gel electrophoresis and mass spectrometry). The results provided extensive data on the functional genomics under conditions that partially mimic plant infection and – in addition - revealed some surprising and significant data. Thus, we identified the genes whose expression is modulated when Agrobacterium is grown under the acidic conditions found in the rhizosphere (pH 5.5), an essential environmental factor in Agrobacterium – plant interactions essential for induction of the virulence program by plant signal molecules. Among the 45 genes whose expression was significantly elevated, of special interest is the two-component chromosomally encoded system, ChvG/I which is involved in regulating acid inducible genes. A second exciting system under acid and ChvG/Icontrol is a secretion system for proteins, T6SS, encoded by 14 genes which appears to be important for Rhizobium leguminosarum nodule formation and nitrogen fixation and for virulence of Agrobacterium. The proteome analysis revealed that gamma aminobutyric acid (GABA), a metabolite secreted by wounded plants, induces the synthesis of an Agrobacterium lactonase which degrades the quorum sensing signal, N-acyl homoserine lactone (AHL), resulting in attenuation of virulence. In addition, through a transcriptomic analysis of Agrobacterium growing at the pH of the rhizosphere (pH=5.5), we demonstrated that salicylic acid (SA) a well-studied plant signal molecule important in plant defense, attenuates Agrobacterium virulence in two distinct ways - by down regulating the synthesis of the virulence (vir) genes required for the processing and transfer of the T-DNA and by inducing the same lactonase, which in turn degrades the AHL. Thus, GABA and SA with different molecular structures, induce the expression of these same genes. The identification of genes whose expression is modulated by conditions that mimic plant infection, as well as the identification of regulatory molecules that help control the early stages of infection, advance our understanding of this complex bacterial-plant interaction and has immediate potential applications to modify it. We expect that the data generated by our research will be used to develop novel strategies for the control of crown gall disease. Moreover, these results will also provide the basis for future biotechnological approaches that will use genetic manipulations to improve bacterial-plant interactions, leading to more efficient DNA transfer to recalcitrant plants and robust symbiosis. These advances will, in turn, contribute to plant protection by introducing genes for resistance against other bacteria, pests and environmental stress.
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Lahav, Ori, Albert Heber i David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, marzec 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
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The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Shomer, Ilan, Ruth E. Stark, Victor Gaba i James D. Batteas. Understanding the hardening syndrome of potato (Solanum tuberosum L.) tuber tissue to eliminate textural defects in fresh and fresh-peeled/cut products. United States Department of Agriculture, listopad 2002. http://dx.doi.org/10.32747/2002.7587238.bard.
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The project sought to understand factors and mechanisms involved in the hardening of potato tubers. This syndrome inhibits heat softening due to intercellular adhesion (ICA) strengthening, compromising the marketing of industrially processed potatoes, particularly fresh peeled-cut or frozen tubers. However, ICA strengthening occurs under conditions which are inconsistent with the current ideas that relate it to Ca-pectate following pectin methyl esterase (PME) activity or to formation of rhamnogalacturonan (RG)-II-borate. First, it was necessary to induce strengthening of the middle lamellar complex (MLX) and the ICA as a stress response in some plant parenchyma. As normally this syndrome does not occur uniformly enough to study it, we devised an efficient model in which ICA-strengthening is induced consistently under simulated stress by short-chain, linear, mono-carboxylic acid molecules (OAM), at 65 oC [appendix 1 (Shomer&Kaaber, 2006)]. This rapid strengthening was insufficient for allowing the involved agents assembly to be identifiable; but it enabled us to develop an efficient in vitro system on potato tuber parenchyma slices at 25 ºC for 7 days, whereas unified stress was reliably simulated by OAMs in all the tissue cells. Such consistent ICA-strengthening in vitro was found to be induced according to the unique physicochemical features of each OAM as related to its lipophilicity (Ko/w), pKa, protonated proportion, and carbon chain length by the following parameters: OAM dissociation constant (Kdiss), adsorption affinity constant (KA), number of adsorbed OAMs required for ICA response (cooperativity factor) and the water-induced ICA (ICAwater). Notably, ICA-strengthening is accompanied by cell sap leakage, reflecting cell membrane rupture. In vitro, stress simulation by OAMs at pH<pKa facilitated the consistent assembly of ICAstrengthening agents, which we were able to characterize for the first time at the molecular level within purified insoluble cell wall of ICA-strengthened tissue. (a) With solid-state NMR, we established the chemical structure and covalent binding to cell walls of suberin-like agents associated exclusively with ICA strengthening [appendix 3 (Yu et al., 2006)]; (b) Using proteomics, 8 isoforms of cell wall-bound patatin (a soluble vacuolar 42-kDa protein) were identified exclusively in ICA-strengthened tissue; (c) With light/electron microscopy, ultrastructural characterization, histochemistry and immunolabeling, we co-localized patatin and pectin in the primary cell wall and prominently in the MLX; (d) determination of cell wall composition (pectin, neutral sugars, Ca-pectate) yielded similar results in both controls and ICA-strengthened tissue, implicating factors other than PME activity, Ca2+ or borate ions; (e) X-ray powder diffraction experiments revealed that the cellulose crystallinity in the cell wall is masked by pectin and neutral sugars (mainly galactan), whereas heat or enzymatic pectin degradation exposed the crystalline cellulose structure. Thus, we found that exclusively in ICA-strengthened tissue, heat-resistant pectin is evident in the presence of patatin and suberinlike agents, where the cellulose crystallinity was more hidden than in fresh control tissue. Conclusions: Stress response ICA-strengthening is simulated consistently by OAMs at pH< pKa, although PME and formation of Ca-pectate and RG-II-borate are inhibited. By contrast, at pH>pKa and particularly at pH 7, ICA-strengthening is mostly inhibited, although PME activity and formation of Ca-pectate or RG-II-borate are known to be facilitated. We found that upon stress, vacuolar patatin is released with cell sap leakage, allowing the patatin to associate with the pectin in both the primary cell wall and the MLX. The stress response also includes formation of covalently bound suberin-like polyesters within the insoluble cell wall. The experiments validated the hypotheses, thus led to a novel picture of the structural and molecular alterations responsible for the textural behavior of potato tuber. These findings represent a breakthrough towards understanding of the hardening syndrome, laying the groundwork for potato-handling strategies that assure textural quality of industrially processed particularly in fresh peeled cut tubers, ready-to-prepare and frozen preserved products.
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Sionov, Edward, Nancy Keller i Shiri Barad-Kotler. Mechanisms governing the global regulation of mycotoxin production and pathogenicity by Penicillium expansum in postharvest fruits. United States Department of Agriculture, styczeń 2017. http://dx.doi.org/10.32747/2017.7604292.bard.
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The original objectives of the study, as defined in the approved proposal, are: To characterize the relationship of CreA and LaeA in regulation of P T production To understand how PacC modulates P. expansumpathogenicity on apples To examine if other secondary metabolites are involved in virulence or P. expansumfitness To identify the signaling pathways leading to PAT synthesis Penicilliumexpansum, the causal agent of blue mould rot, is a critical health concern because of the production of the mycotoxinpatulin (PAT) in colonized apple fruit tissue. Although PAT is produced by many Penicilliumspecies, the factors activating its biosynthesis were not clear. This research focused on host and fungal mechanisms of activation of LaeA (the global regulator of secondary metabolism), PacC (the global pH modulator) and CreA (the global carbon catabolite regulator) on PAT synthesis with intention to establish P. expansumas the model system for understanding mycotoxin synthesis in fruits. The overall goal of this proposal is to identify critical host and pathogen factors that mechanistically modulate P. expansumgenes and pathways to control activation of PAT production and virulence in host. Several fungal factors have been correlated with disease development in apples, including the production of PAT, acidification of apple tissue by the fungus, sugar content and the global regulator of secondary metabolism and development, LaeA. An increase in sucrose molarity in the culture medium from 15 to 175 mM negatively regulated laeAexpression and PAT accumulation, but, conversely, increased creAexpression, leading to the hypothesis that CreA could be involved in P. expansumPAT biosynthesis and virulence, possibly through the negative regulation of LaeA. We found evidence for CreAtranscriptional regulation of laeA, but this was not correlated with PAT production either in vitro or in vivo, thus suggesting that CreA regulation of PAT is independent of LaeA. Our finding that sucrose, a key ingredient of apple fruit, regulates PAT synthesis, probably through suppression of laeAexpression, suggests a potential interaction between CreA and LaeA, which may offer control therapies for future study. We have also identified that in addition to PAT gene cluster, CreA regulates other secondary metabolite clusters, including citrinin, andrastin, roquefortine and communesins, during pathogenesis or during normal fungal growth. Following creation of P. expansumpacCknockout strain, we investigated the involvement of the global pH regulator PacC in fungal pathogenicity. We demonstrated that disruption of the pH signaling transcription factor PacC significantly decreased the virulence of P. expansumon deciduous fruits. This phenotype is associated with an impairment in fungal growth, decreased accumulation of gluconic acid and reduced synthesis of pectolytic enzymes. We showed that glucose oxidase- encoding gene, which is essential for gluconic acid production and acidification during fruit colonization, was significantly down regulated in the ΔPepacCmutant, suggesting that gox is PacC- responsive gene. We have provided evidence that deletion of goxgene in P. expansumled to a reduction in virulence toward apple fruits, further indicating that GOX is a virulence factor of P. expansum, and its expression is regulated by PacC. It is also clear from the present data that PacC in P. expansumis a key factor for the biosynthesis of secondary metabolites, such as PAT. On the basis of RNA-sequencing (RNA-seq) analysis and physiological experimentation, the P. expansumΔlaeA, ΔcreAand ΔpacCmutants were unable to successfully colonize apples for a multitude of potential mechanisms including, on the pathogen side, a decreased ability to produce proteolytic enzymes and to acidify the environment and impaired carbon/nitrogen metabolism and, on the host side, an increase in the oxidative defence pathways. Our study defines these global regulatory factors and their downstream signalling pathways as promising targets for the development of strategies to fight against this post-harvest pathogen.
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Droby, Samir, Michael Wisniewski, Ron Porat i Dumitru Macarisin. Role of Reactive Oxygen Species (ROS) in Tritrophic Interactions in Postharvest Biocontrol Systems. United States Department of Agriculture, grudzień 2012. http://dx.doi.org/10.32747/2012.7594390.bard.
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To elucidate the role of ROS in the tri-trophic interactions in postharvest biocontrol systems a detailed molecular and biochemical investigation was undertaken. The application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. The expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. The yeast antagonists, Metschnikowia fructicola (strain 277) and Candida oleophila (strain 182) generate relatively high levels of super oxide anion (O2−) following its interaction with wounded fruit surface. Using laser scanning confocal microscopy we observed that the application of M. fructicola and C. oleophila into citrus and apple fruit wounds correlated with an increase in H2O2 accumulation in host tissue. The present data, together with our earlier discovery of the importance of H₂O₂ production in the defense response of citrus flavedo to postharvest pathogens, indicate that the yeast-induced oxidative response in fruit exocarp may be associated with the ability of specific yeast species to serve as biocontrol agents for the management of postharvest diseases. Effect of ROS on yeast cells was also studied. Pretreatment of the yeast, Candida oleophila, with 5 mM H₂O₂ for 30 min (sublethal) increased yeast tolerance to subsequent lethal levels of oxidative stress (50 mM H₂O₂), high temperature (40 °C), and low pH (pH 4). Suppression subtractive hybridization analysis was used to identify genes expressed in yeast in response to sublethal oxidative stress. Transcript levels were confirmed using semi quantitative reverse transcription-PCR. Seven antioxidant genes were up regulated. Pretreatment of the yeast antagonist Candida oleophila with glycine betaine (GB) increases oxidative stress tolerance in the microenvironment of apple wounds. ROS production is greater when yeast antagonists used as biocontrol agents are applied in the wounds. Compared to untreated control yeast cells, GB-treated cells recovered from the oxidative stress environment of apple wounds exhibited less accumulation of ROS and lower levels of oxidative damage to cellular proteins and lipids. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and Botrytis cinerea, and faster growth in wounds of apple fruits compared to untreated yeast. The expression of major antioxidant genes, including peroxisomal catalase, peroxiredoxin TSA1, and glutathione peroxidase was elevated in the yeast by GB treatment. A mild heat shock (HS) pretreatment (30 min at 40 1C) improved the tolerance of M. fructicola to subsequent high temperature (45 1C, 20–30 min) and oxidative stress (0.4 mol-¹) hydrogen peroxide, 20–60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than non-treated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P≥0.0001) biocontrol activity against Penicillium expansum and a significantly faster (Po0.0001) growth rate in wounds of apple fruits stored at 25 1C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was up regulated in response to HS and trehalose content also increased.
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Prusky, Dov, Nancy P. Keller i Amir Sherman. global regulation of mycotoxin accumulation during pathogenicity of Penicillium expansum in postharvest fruits. United States Department of Agriculture, styczeń 2014. http://dx.doi.org/10.32747/2014.7600012.bard.
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Background to the topic- Penicilliumas a postharvest pathogen and producer of the mycotoxin PAT. Penicilliumspp. are destructive phytopathogens, capable of causing decay in many deciduous fruits, during postharvest handling and storage; and the resulting losses can amount to 10% of the stored produce and the accumulation of large amounts of the mycotoxinpatulin. The overall goal of this proposal is to identify critical host and pathogen factors that modulate P. expansummycotoxin genes and pathways which are required for PAT production and virulence. Our preliminary results indicated that gluconic acid are strongly affecting patulin accumulation during colonization. P. expansumacidifies apple fruit tissue during colonization in part through secretion of gluconic acid (GLA). Several publications suggested that GLA accumulation is an essential factor in P. expansumpathogenicity. Furthermore, down regulation of GOX2 significantly reduced PAT accumulation and pathogenicity. PAT is a polyketide and its biosynthesis pathway includes a 15-gene cluster. LaeA is a global regulator of mycotoxin synthesis. It is now known that patulin synthesis might be subjected to LaeA and sometimes by environmental sensing global regulatory factors including the carbon catabolite repressor CreA as well as the pH regulator factor PacC and nitrogen regulator AreA. The mechanisms by which LaeA regulates patulin synthesis was not fully known and was part of our work. Furthermore, the regulatory system that controls gene expression in accordance with ambient pH was also included in our work. PacC protein is in an inactive conformation and is unable to bind to the promoter sites of the target genes; however, under alkaline growth conditions activated PacC acts as both an activator of alkaline-expressed genes and a repressor of acid-expressed genes. The aims of the project- This project aims to provide new insights on the roles of LaeA and PacC and their signaling pathways that lead to GLA and PAT biosynthesis and pathogenicity on the host. Specifically, our specific aims were: i) To elucidate the mechanism of pH-controlled regulation of GLA and PAT, and their contribution to pathogenesis of P. expansum. We are interested to understanding how pH and/or GLA impact/s under PacC regulation affect PAT production and pathogenesis. ii) To characterize the role of LaeA, the global regulator of mycotoxin production, and its effect on PAT and PacC activity. iii) To identify the signaling pathways leading to GLA and PAT synthesis. Using state- of-the-art RNAseq technologies, we will interrogate the transcriptomes of laeAand pacCmutants, to identify the common signaling pathways regulating synthesis of both GLA and PAT. Major conclusions, solutions, achievements- In our first Aim our results demonstrated that ammonia secreted at the leading edge of the fungal colony induced transcript activation of the global pH modulator PacC and PAT accumulation in the presence of GLA. We assessed these parameters by: (i) direct exogenous treatment of P. expansumgrowing on solid medium; (ii) direct exogenous treatment on colonized apple tissue; (iii) growth under self-ammonia production conditions with limited carbon; and (iv) analysis of the transcriptional response to ammonia of the PAT biosynthesis cluster. Ammonia induced PAT accumulation concurrently with the transcript activation of pacCand PAT biosynthesis cluster genes, indicating the regulatory effect of ammonia on pacCtranscript expression under acidic conditions. Transcriptomic analysis of pH regulated processes showed that important genes and BARD Report - Project 4773 Page 2 of 10 functionalities of P. expansumwere controlled by environmental pH. The differential expression patterns of genes belonging to the same gene family suggest that genes were selectively activated according to their optimal environmental conditions to enable the fungus to cope with varying conditions and to make optimal use of available enzymes. Concerning the second and third Aims, we demonstrated that LaeA regulates several secondary metabolite genes, including the PAT gene cluster and concomitant PAT synthesis invitro. Virulence studies of ΔlaeAmutants of two geographically distant P. expansumisolates (Pe-21 from Israel and Pe-T01 from China) showed differential reduction in disease severity in freshly harvested fruit ranging from no reduction for Ch-Pe-T01 strains in immature fruit to 15–25% reduction for both strains in mature fruit, with the ΔlaeAstrains of Is-Pe-21 always showing a greater loss in virulence. Results suggest the importance of LaeA regulation of PAT and other secondary metabolites on pathogenicity. Our work also characterized for the first time the role of sucrose, a key nutritional factor present in apple fruit, as a negative regulator of laeAexpression and consequent PAT production in vitro. This is the first report of sugar regulation of laeAexpression, suggesting that its expression may be subject to catabolite repression by CreA. Some, but not all of the 54 secondary metabolite backbone genes in the P. expansumgenome, including the PAT polyketide backbone gene, were found to be regulated by LaeA. Together, these findings enable for the first time a straight analysis of a host factor that potentially activates laeAand subsequent PAT synthesis.
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Delwiche, Michael, Boaz Zion, Robert BonDurant, Judith Rishpon, Ephraim Maltz i Miriam Rosenberg. Biosensors for On-Line Measurement of Reproductive Hormones and Milk Proteins to Improve Dairy Herd Management. United States Department of Agriculture, luty 2001. http://dx.doi.org/10.32747/2001.7573998.bard.
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The original objectives of this research project were to: (1) develop immunoassays, photometric sensors, and electrochemical sensors for real-time measurement of progesterone and estradiol in milk, (2) develop biosensors for measurement of caseins in milk, and (3) integrate and adapt these sensor technologies to create an automated electronic sensing system for operation in dairy parlors during milking. The overall direction of research was not changed, although the work was expanded to include other milk components such as urea and lactose. A second generation biosensor for on-line measurement of bovine progesterone was designed and tested. Anti-progesterone antibody was coated on small disks of nitrocellulose membrane, which were inserted in the reaction chamber prior to testing, and a real-time assay was developed. The biosensor was designed using micropumps and valves under computer control, and assayed fluid volumes on the order of 1 ml. An automated sampler was designed to draw a test volume of milk from the long milk tube using a 4-way pinch valve. The system could execute a measurement cycle in about 10 min. Progesterone could be measured at concentrations low enough to distinguish luteal-phase from follicular-phase cows. The potential of the sensor to detect actual ovulatory events was compared with standard methods of estrus detection, including human observation and an activity monitor. The biosensor correctly identified all ovulatory events during its testperiod, but the variability at low progesterone concentrations triggered some false positives. Direct on-line measurement and intelligent interpretation of reproductive hormone profiles offers the potential for substantial improvement in reproductive management. A simple potentiometric method for measurement of milk protein was developed and tested. The method was based on the fact that proteins bind iodine. When proteins are added to a solution of the redox couple iodine/iodide (I-I2), the concentration of free iodine is changed and, as a consequence, the potential between two electrodes immersed in the solution is changed. The method worked well with analytical casein solutions and accurately measured concentrations of analytical caseins added to fresh milk. When tested with actual milk samples, the correlation between the sensor readings and the reference lab results (of both total proteins and casein content) was inferior to that of analytical casein. A number of different technologies were explored for the analysis of milk urea, and a manometric technique was selected for the final design. In the new sensor, urea in the sample was hydrolyzed to ammonium and carbonate by the enzyme urease, and subsequent shaking of the sample with citric acid in a sealed cell allowed urea to be estimated as a change in partial pressure of carbon dioxide. The pressure change in the cell was measured with a miniature piezoresistive pressure sensor, and effects of background dissolved gases and vapor pressures were corrected for by repeating the measurement of pressure developed in the sample without the addition of urease. Results were accurate in the physiological range of milk, the assay was faster than the typical milking period, and no toxic reagents were required. A sampling device was designed and built to passively draw milk from the long milk tube in the parlor. An electrochemical sensor for lactose was developed starting with a three-cascaded-enzyme sensor, evolving into two enzymes and CO2[Fe (CN)6] as a mediator, and then into a microflow injection system using poly-osmium modified screen-printed electrodes. The sensor was designed to serve multiple milking positions, using a manifold valve, a sampling valve, and two pumps. Disposable screen-printed electrodes with enzymatic membranes were used. The sensor was optimized for electrode coating components, flow rate, pH, and sample size, and the results correlated well (r2= 0.967) with known lactose concentrations.
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Avnimelech, Yoram, Richard C. Stehouwer i Jon Chorover. Use of Composted Waste Materials for Enhanced Ca Migration and Exchange in Sodic Soils and Acidic Minespoils. United States Department of Agriculture, czerwiec 2001. http://dx.doi.org/10.32747/2001.7575291.bard.
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Restoration of degraded lands and the development of beneficial uses for waste products are important challenges facing our society. In addition there is a need to find useful and environmentally friendly applications for the organic fractions of municipal and other solid waste. Recent studies have shown that composted wastes combined with gypsum or gypsum-containing flue gas desulfurization by-products enhance restoration of sodic soils and acidic minespoils. The mechanism by which this synergistic effect occurs in systems at opposite pH extremes appears to involve enhanced Ca migration and exchange. Our original research objectives were to (1) identify and quantify the active compost components involved in Ca transport, (2) determine the relative affinity of the compost components for Ca and competing metals in the two soil/spoil systems, (3) determine the efficacy of the compost components in Ca transport to subjacent soil and subsequent exchange with native soil cations, and (4) assess the impacts of compost enhanced Ca transport on soil properties and plant growth. Acidic mine spoils: During the course of the project the focus for objective (1) and (2) shifted more towards developing and evaluating methods to appropriately quantify Ca2+ and Al3+ binding to compost derived dissolved organic matter (DOM). It could be shown that calcium complexation by sewage sludge compost derived DOM did not significantly change during the composting process. A method for studying Al3+ binding to DOM was successfully developed and should allow future insight into DOM-Al3+ interactions in general. Laboratory column experiments as well as greenhouse experiments showed that in very acidic mine spoil material mineral dissolution controls solution Al3+ concentration as opposed to exchange with Ca2+. Therefore compost appeared to have no effect on Al3+ and Ca2+ mobility and did not affect subsoil acidity. Sodic alkaline soils: Batch experiments with Na+ saturated cation exchange resins as a model for sodic soils showed that compost home cations exchanged readily with Na+. Unlike filtered compost extracts, unfiltered compost suspensions also significantly increased Ca2+ release from CaCO3. Soil lysimeter experiments demonstrated a clear impact of compost on structural improvement in sodic alkaline soils. Young compost had faster, clearer and longer lasting effects on soil physical and chemical properties than mature compost. Even after 2 growing seasons differences could still be observed. Compost increased Ca2+ concentration in soil solution and solubility of pedogenic CaCO3 that is highly insoluble under alkaline conditions. The solubilized Ca2+ efficiently exchanged Na+ in the compost treated soils and thus greatly improved the soil structure.
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Bowles, David, Michael Williams, Hope Dodd, Lloyd Morrison, Janice Hinsey, Tyler Cribbs, Gareth Rowell, Michael DeBacker, Jennifer Haack-Gaynor i Jeffrey Williams. Protocol for monitoring aquatic invertebrates of small streams in the Heartland Inventory & Monitoring Network: Version 2.1. National Park Service, kwiecień 2021. http://dx.doi.org/10.36967/nrr-2284622.
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The Heartland Inventory and Monitoring Network (HTLN) is a component of the National Park Service’s (NPS) strategy to improve park management through greater reliance on scientific information. The purposes of this program are to design and implement long-term ecological monitoring and provide information for park managers to evaluate the integrity of park ecosystems and better understand ecosystem processes. Concerns over declining surface water quality have led to the development of various monitoring approaches to assess stream water quality. Freshwater streams in network parks are threatened by numerous stressors, most of which originate outside park boundaries. Stream condition and ecosystem health are dependent on processes occurring in the entire watershed as well as riparian and floodplain areas; therefore, they cannot be manipulated independently of this interrelationship. Land use activities—such as timber management, landfills, grazing, confined animal feeding operations, urbanization, stream channelization, removal of riparian vegetation and gravel, and mineral and metals mining—threaten stream quality. Accordingly, the framework for this aquatic monitoring is directed towards maintaining the ecological integrity of the streams in those parks. Invertebrates are an important tool for understanding and detecting changes in ecosystem integrity, and they can be used to reflect cumulative impacts that cannot otherwise be detected through traditional water quality monitoring. The broad diversity of invertebrate species occurring in aquatic systems similarly demonstrates a broad range of responses to different environmental stressors. Benthic invertebrates are sensitive to the wide variety of impacts that influence Ozark streams. Benthic invertebrate community structure can be quantified to reflect stream integrity in several ways, including the absence of pollution sensitive taxa, dominance by a particular taxon combined with low overall taxa richness, or appreciable shifts in community composition relative to reference condition. Furthermore, changes in the diversity and community structure of benthic invertebrates are relatively simple to communicate to resource managers and the public. To assess the natural and anthropo-genic processes influencing invertebrate communities, this protocol has been designed to incorporate the spatial relationship of benthic invertebrates with their local habitat including substrate size and embeddedness, and water quality parameters (temperature, dissolved oxygen, pH, specific conductance, and turbidity). Rigid quality control and quality assurance are used to ensure maximum data integrity. Detailed standard operating procedures (SOPs) and supporting information are associated with this protocol.