Development of Electrochemical Methods for Detection of Pesticides and Biofuel Production

Electrochemical methods coupled with biological elements are used in industrial, medical and environmental applications. In this thesis we will discuss two such applications: an electrochemical biosensor for detection of pesticides and biofuel generation using electrochemical methods coupled with microorganisms. Electrochemical biosensors are commonly used as a result of their selectivity, sensitivity, rapid response and portability. A common application for electrochemical biosensors is detection of pesticides and toxins in water samples. In this thesis, we will focus on detection of organosphosphates (OPs), a group of compounds that are commonly used as pesticides and nerve agents. Rapid and sensitive detection of these compounds has been an area of active research due to their high toxicity. Amperometric and potentiometric electrochemical biosensors that use organophosphorus hydrolase (OPH), an enzyme that can hydrolyze a broad class of OPs, have been reported for field detection of OPs. Amperometry is used for detection of electroactive leaving groups and potentiometry is used for detection of pH changes that take place during the hydrolysis reaction. Both these methods have limitations: using amperometric biosensors, very low limits of detection are achieved but this method is limited to the few OPs with electroactive leaving groups, on the other hand potentiometric biosensor can be used for detection of all OPs but they don't have low enough limits of detection. We have developed a novel dual enzyme biosensor biosensor with OPH and horseradish peroxidase (HRP) for detection of OPs with phenolic leaving groups which are much more common than electroactive leaving groups. This biosensor was used for detection of dichlofenthion, an OP which does not have an electroactive leaving group. Electrochemical biosensors with enzymatic layers such as the one described above are commonly used, however there are no clear guidelines on how to design these sensors. Based on the application, the biosensor might be designed for a target limit of detection, sensitivity and/or linear range. Simulation tools can be used to provide general guidelines that can be applied to a wide range of biosensors and reduce extensive development time. In chapter 3, reaction-diffusion equations for an enzymatic biosensor with saturation kinetics are solved. Dimensionless numbers that can guide the researchers on designing and optimizing biosensors are presented. Additionally results from a formaldehyde biosensor are presented to demonstrate the use of some of the guidelines introduced. Recently biofuel production using electricity has become an attractive area of research in the interface between electrochemistry and biology. Biofuel production from renewable resources is the challenge of our century. Bioproduction using natural photosynthesis routes suffers from low efficiencies. An alternative to photosynthesis is the use of chemolithoautotrophic organisms that are genetically engineered to produce biofuels. These organisms use inorganic redox mediators as their energy source instead of photosynthesis. A sustainable biofuel production process is feasible, if the chemolithoautotrophic organisms are coupled with an electrochemical reactor to recycle the redox mediator. We will describe the development of an electrochemical reactor that reduces nitrite to ammonia which is the natural mediator couple for the chemolithoautotrophic organism Nitrosomonas europaea. Using nickel and glassy carbon electrodes nearly 100% current efficiencies were obtained in batch electrolysis experiments in media optimal for N.europaea growth. Additionally effect of production of the potential biofuel isobutanol on cathode performance was studied. A flow-by electrochemical reactor with a porous electrode was designed to supply sufficient ammonia to a 5 L chemostat containing wild type N.europaea. Biomass production using electrochemically regenerated mediator was demonstrated by coupling this electrochemical reactor with N.europaea chemostat. Ammonia removal and biomass yield for the bacteria were unaffected by the coupled operation which suggests the electrochemically reduced media did not alter aerobic metabolism of the bacteria. Reduction of nitrite to ammonia was further investigated using linear sweep voltammetry and electrochemical impedance spectroscopy. A limiting current plateau was identified in linear sweep experiments. In the pH range between 6.0 and 8.0, the flux of protons to the electrode were determined to cause mass transfer limitations. The same electrochemical methods were also used to assess the changes in performance of cathodes with time. Formation of a film was observed on glassy carbon and nickel electrodes. The film did not seem to cause any changes to the nickel electrode. On the other hand overpotential for the glassy carbon electrode was significantly reduced which would decrease power requirements for the electrochemical reactor and the overall process

Gender justice at post-conflict reconstruction: implementation of women's political rights at election periods in the case of post-conflict Afghanistan

In conflict environments, women are often denied justice. This situation is being challenged for post-conflict environments with the initiations on gender-equal approaches. The integration of human rights language, specifically women’s rights, into post-conflict reconstruction, paves the way for gender-equal environments. The commitments to gender equality and women's empowerment on a wider context of transformative possibilities have converted the post-conflict settings as “opportunity spaces” for women. Concerns for the inclusion of women in post-conflict reconstruction, backed by the United Nations Security Council Resolution 1325, is an important contributing cause for the integration of human rights and gender equal language into post-conflict Afghanistan. The unique opportunities exist for women to participate in developing constitutional, legislative and judicial structures for gender equality in the phase of transitional justice with affirmative action inputs. The collaborations and disagreements in between United Nations’ and Government’s agencies and national commissions are studied in order to show the effectiveness of the practical implementations on political rights of women in these two election periods: Presidential and Parliamentary. The research was based on whether practical issues for the implementation women’s political rights, such as freedom of expression, freedom of movement, and principle of non-discrimination, principle of non-intimidation, had been the source of disagreement due to an ideological difference between the UN units, national commissions, and related ministries. The approaches taken by these units as the main focus, reaches conclusions on whether the affirmative action stated with the constitutional reform and electoral laws, besides the related international conventions signed by Islamic Republic of Afghanistan, for the political representation of Afghan women, have been implied effectively and have been successful so the “opportunity space” for women in Afghanistan has become a truth

Utility of brain parenchyma density measurement and computed tomography perfusion imaging in predicting brain death

Purpose: To assess the utility of brain parenchyma density measurement on unenhanced computed tomography (CT) in predicting brain death (BD), in order to evaluate the added value of CT perfusion (CTP). Material and methods: A total of 77 patients who were clinically diagnosed as BD and had both CT angiography (CTA) and CTP imaging in the same session were retrospectively reviewed. On unenhanced phase of CTA, density measurement was performed from 23 regions of interests (ROIs) which were located in the following areas: level of basal ganglia (caudate nucleus, putamen, corpus callosum, posterior limb of internal capsule), level of brainstem, greywhite matters on levels of centrum semiovale (CS), high convexity (HC), and cerebellum. CTP images were evaluated qualitatively and independently. Grey matter (GM), white matter (WM), density, and GM/WM density ratio of BD patients were compared with control subjects. Results: Comparing with the normal control group, the GM and WM density at each level and GM/WM density ratio of CS, HC, and cerebellum level were significantly lower in brain-dead patients (p = 0.019 for HC-WM, p < 0.001 for other areas). Using ROC analysis, the highest value of area under curve (AUC) for the GM/WM density ratio was found at the HC level (AUC = 0.907). The sensitivity of the GM/WM density ratio at the HC level was found to be 90% when the cut-off value of 1.25 was identified. Evaluating the GM/WM density ratio together with the CTP results increased the sensitivity further to 98%. Conclusions: The GM/WM density ratio at the HC level on unenhanced CT may be a useful finding to predict BD. Also, the addition of CTP increases the sensitivity of this method

Laryngeal involvement in patients with active pulmonary tuberculosis

The aim of this study was to determine the incidence of laryngeal tuberculosis (LT) among patients with active pulmonary tuberculosis. A total of 319 patients under treatment for pulmonary tuberculosis were subjected to laryngoscopy. Five patients (1.5%) with LT were identified. Odynophagia was the most common complaint, followed by alteration in voice. The larynx returned to its normal appearance in 3-8months (average 18weeks) by antituberculous medication. Physicians dealing with pulmonary tuberculosis should keep in mind that symptoms of laryngeal involvement may be minor, and laryngoscopy should always be performed when laryngeal involvement is suspected in order to isolate highly infectious patients. Response to antituberculous medication is usually late in LT and diagnosis by "wait and watch” policy will cause a significant delay in the diagnosis of a possible larynx carcinom

Inter-Observer Agreement on Diffusion-Weighted Magnetic Resonance Imaging Interpretation for Diagnosis of Acute Ischemic Stroke Among Emergency Physicians

SUMMARYObjectivesDiffusion-weighted magnetic resonance imaging (DW-MRI) is a highly sensitive tool for the detection of early ischemic stroke and is excellent at detecting small and early infarcts. Nevertheless, conflict may arise and judgments may differ among different interpreters. Inter-observer variability shows the systematic difference among different observers and is expressed as the kappa (Κ) coefficient. In this study, we aimed to determinate the inter-observer variability among emergency physicians in the use of DW-MRI for the diagnosis of acute ischemic stroke.MethodsCranial DW-MRI images of 50 patients were interpreted in this retrospective observational cross-sectional study. Patients who were submitted to DW-MRI imaging for a suspected acute ischemic stroke were included in the study, unless the scans were ordered by any of the reviewers or they were absent in the system. The scans were blindly and randomly interpreted by four emergency physicians. Inter-observer agreement between reviewers was evaluated using Fleiss’ Κ statistics.ResultsThe mean kappa value for high signal on diffusion-weighted images (DWI) and for reduction on apparent diffusion coefficient (ADC) were substantial (k=0.67) and moderate (k=0.60) respectively. The correlation for detection of the presence of ischemia and location was substantial (k: 0.67). There were 18 false-positive and 4 false-negative evaluations of DWI, 15 false positive and 8 false-negative evaluations of ADC.ConclusionsOur data suggest that DW-MRI is reliable in screening for ischemic stroke when interpreted by emergency physicians in the emergency department. The levels of stroke identification and variability show that emergency physicians may have an acceptable level of agreement

A Qualitative Modeling Method for Platform Design

The development of a collection of related products sharing a common platform represents an important approach in modern product design. an ongoing problem is the application of design methods toward a limited set of evolving product data and archived design knowledge to search and explore alternative platform options. with the goal of maximizing the reuse of end item artifacts and supply chain elements, we propose a design modeling method using basic qualitative relationships among relevant performance, design, and noise parameters in the system of interest. by using qualitative models related to multiple levels of design data, the method provides a single high level graphical representation among design data including archived knowledge in a design repository. © 2005 IEEE

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI