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High-throughput analysis of contrived cocaine mixtures by direct analysis in real time/single quadrupole mass spectrometry and post acquisition chemometric analysisHorsley, Andrew Blair 12 March 2016 (has links)
Direct Analysis in Real Time (DART) ionization/mass spectrometry allows for the high throughput analysis of a wide range of materials including but not limited to: solids, liquids, powders, tablets, and plant materials. The ability to detect cocaine was established in a reproducible manner with the use of a DART ionization source (IonSense Inc., Saugus, MA) interfaced to a modified single quadrupole mass spectrometer. Development of a methodology for the detection of cocaine within contrived street quality drug mixtures involved the optimization of the ionization source, sample introduction mechanism, ion guide, and mass analysis parameters. An analytical method was created that utilized ionized helium carrier gas heated to 300°C and an automated sample introduction apparatus consisting of a Linear Rail Enclosure that holds consumable QuickStrip^TM sample cards. Ionized molecules were then fragmented by manipulation of voltage levels within the ion guide to gain more structural information prior to detection by a single quadrupole mass spectrometer.
Cocaine was detected by the modified DART/MS analytical platform and gave two peaks within the mass spectrum at m/z 304 and 182. Optimization of in-source fragmentation by manual adjustment of the skimmer focus voltage allowed for the reproducible fragmentation of cocaine and the ability to increase or decrease the amount of fragmentation seen between the two peaks detected for cocaine. With the use of fragmentation, this analytical platform can be classified as a Category A technique as defined by the Scientific Working Group for the Analysis of Seized Drugs.
The robust detection of cocaine was demonstrated for reference samples at concentrations as low as 10 ng/μL (50 ng) with high signal abundance greater than ten times the signal to noise ratio. Furthermore, the detection of cocaine at 10 ng/μL was demonstrated for multi component mixtures of up to 14 additional components containing common adulterants and diluents found within street quality samples. In total, 25 common excipients were tested using the same method parameters as optimized for cocaine analysis. Of these 25 excipients tested, five were not detected in positive ion mode (one could be detected in negative ion mode). Of the twenty excipients that could be detected by mass spectrometry, two pairs of excipients (levamisole/tetramisole and creatine/creatinine) could not be differentiated from each other. There were no excipients tested that had equivalent m/z values as those of cocaine. Experimentation into the effects of various excipients at multiple concentrations on the abundance of the two cocaine peaks was performed. Regardless of excipient amount (up to 10 times more concentrated than cocaine) and the number of components (up to 15 total components) the ratio of abundance between the m/z 304 to 182 peaks did not vary greater than 22% relative standard deviation.
A match criteria protocol was developed for the ability of an analyst to confirm the presence of cocaine within unknown forensic case samples that have previously tested positive for the presumptive identification of cocaine. The identification of cocaine was based on various factors such as the signal to noise ratio at m/z 304 and 182, the ratio of abundance between those two peaks as well as positive and negative controls. This match criteria protocol was utilized for 25 double blind mock forensic casework samples was performed. Determination for the presence of cocaine within these unknown samples gave an analyst error rate of 0%, with no false positives or false negatives predicted.
To further aid human interpretation and identification of compounds within mixtures, the advanced chemometric software, Analyze IQ, was utilized. Development of predictive classification models using a combination of pre-processing steps, principle component analysis and machine learning techniques was achieved. Models were built using 381 unique samples for the purposes of identifying the presence of cocaine within unknown samples. Of all methods available within the Analyze IQ software, the optimization of a model using principle component analysis with support vector machine regression with a radial basis function kernel yielded an initial error rate of 0% for 72 samples tested. Furthermore, of the samples tested against the model, 20 samples were comprised of excipients that were not incorporated into the initial model development process. The inclusion of these samples (10 spiked with cocaine, 10 absent of cocaine), shows that predictive modeling based software can provide an accurate, robust, and evolving approach to the identification of cocaine within sample compositions that have not previously been tested and stored in a database of known reference samples. Predictive modeling has advantages over current mass spectral libraries, which are limited to the identification of pure compounds. To further test the abilities of predictive models, optimized machine learning models were applied to 25 double blind mock forensic casework samples. The predictive modeling error rate was identical to the human interpretation rate for the double blind mock casework samples with a 0% error rate.
Using the DART/MS analytical platform, 25 mock forensic casework samples along with positive and negative controls were analyzed and identified for the presence of cocaine within 30 minutes. On the order of 15 to 30 times faster than modern GC/MS and LC/MS methods, the ability to analyze and identify samples faster would allow for an increase in samples being processed on a daily basis and allow for the reduction of case backlogs that currently plague controlled substances sections of forensic science laboratories throughout the United States.
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E-dart : um ambiente de especificação e-lotos / E-DART - an E-LOTOS specification environmentGranville, Lisandro Zambenedetti January 1998 (has links)
O aumento crescente da complexidade dos sistemas computacionais criou a necessidade do uso de técnicas de descrição formal (TDFs) na definição, implementação e manutenção dos sistemas. Contudo, apenas a existência de técnicas de descrição formal não garante o eficiente emprego das mesmas na especificação dos sistemas. É necessária a existência de ferramentas que viabilizem o uso das TDFs de forma que estas possam ser efetivamente úteis no desenvolvimento de projetos. Este trabalho apresenta os resultados obtidos da construção de um ambiente de especificação gráfico, onde a TDF E-LOTOS (Enhancements to LOTOS) fornece os mecanismos que uma técnica de descrição deve possuir para viabilizar a consistência, verificação e validação de sistemas. A TDF é suportada através do emprego de uma nova versão gráfica para a sintaxe textual padrão de E-LOTOS. O principal objetivo deste trabalho é disponibilizar aos projetistas e desenvolvedores um ambiente de especificação onde a criação, implementação, teste e manutenção de sistemas sejam feitos de forma fácil, rápida, intuitiva e consistente. Para tal, uma nova sintaxe gráfica de E-LOTOS foi criada: o E-DART (Enhancements to DART). Foi desenvolvida também uma ferramenta que permite o uso de E-DART, o Editor E-DART. A nova sintaxe abstrai, através de diagramas, as complexidades naturais de E-LOTOS, permitindo uma compreensão mais intuitiva dos sistemas. Com o uso de E-DART as especificações construídas são validadas por uma TDF sem que o processo de criação torne-se complexo. No Editor E-DART, a rapidez na criação das especificações é alcançada com mecanismos de reuso de módulos, e com o emprego de recursos avançados de interação com o usuário. O reuso de módulos diminui o tempo total dispensado na criação de especificações porque as mesmas poderão utilizar partes já homologadas de outros sistemas, sem a necessidade de validação e testes, pois estes são procedimentos realizados anteriormente nas outras especificações. Os recursos avançados de interação, por outro lado, permitem que projetistas não familiarizados com E-LOTOS sejam ainda assim capazes de construir sistemas complexos. Além disso, profissionais que tenham experiência com a TDF têm acesso direto ao código textual E-LOTOS, o que lhes garante uma maior compreensão das especificações. / The increasing complexity of the computational systems has created the necessity of the use of formal description techniques (FDTs) in the systems definition, implementation and maintenance. However, only the existence of formal description techniques does not guarantee their efficient use in the systems specification. The existence of tools is necessary to make the use of the TDFFs possible in a way in which these techniques can be effectively useful in projects development. This work presents the results of the construction of a specification graphical environment, where E-LOTOS FDT (Enhancements to LOTOS) supplies the mechanisms that a description technique must possess to make possible the consistency, verification and validation of systems. The FDT is supported through the use of a new graphical version for the standard textual E-LOTOS syntax. The main goal of this work is to provide to designers and developers a specification environment where the creation, implementation, test and maintenance of systems are made in a easy form, fast, intuitive and consistent way. For such, a new graphical syntax of E-LOTOS was created: the E-DART (Enhancements to DART). A tool that allows the E-DART use was also developed, the E-DART Editor. The new syntax represents, through diagrams, the natural complexities of E-LOTOS, allowing a intuitive understanding of the systems. With the use of E-DART the specifications are still validated by a FDT, without turning their creation into a complex process. In the E-DART Editor, fast creation of the specifications is achieved with mechanisms of module reuse, and with the use of advanced user interaction resources. The reuse of module diminishes the total time used in the specifications creation because it will be possible to use parts already validated of other systems. The advanced interaction resources, on the other hand, allow that designers not familiarized with E-LOTOS to be able to construct complex systems. Moreover, professionals who have experience with the FDT have direct access to textual ELOTOS code, which guarantees an easier understanding of the specifications.
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Development of high-sensitivity atmospheric pressure (ap) matrix-assisted laser desorption/ionization (maldi) and open air ionization techniques for the analysis of biomolecules by mass spectrometryNavare, Arti T. 29 March 2010 (has links)
Matrix-assisted laser desorption/ionization (MALDI) has been celebrated as a soft ionization method for analyzing very diverse biological species including large proteins, peptides, carbohydrates, lipids and metabolites. The fact that MALDI is tolerant to salts and buffers and that it mostly produces singly charged ions from intact biomolecules is considered highly advantageous over electrospray ionization (ESI). Almost two decades after the introduction of vacuum MALDI, the technique was successfully implemented under atmospheric pressure (AP) conditions by Laiko and co-workers. Some of the most salient advantages of AP-MALDI over vacuum MALDI are its ability to generate intact ions from labile species with minimal fragmentation due to collisional cooling under AP, the ability of performing MSn experiments, and its exchangeability with other ion sources. However, AP-MALDI suffers from limited sensitivity due to low ion transmission efficiency under AP conditions. Because sensitivity is a function of the sample pretreatment method of choice, both preconcentration and selective sample fractionation can be used during the initial stages of the analytical pipeline to improve detectability.
To that end, the first part of the work presented in this thesis is aimed at investigating various approaches to improve the sensitivity of AP-MALDI for mass spectrometric analysis of biomolecules. Chapter 1 reviews the history of laser desorption ionization (LDI), presenting salient features of vacuum MALDI and AP-MALDI, and concludes with a brief overview of leading ambient ionization techniques, such as Direct Analysis in Real Time (DART) ionization. Chapter 2 presents an investigation of an on chip sample preconcentration approach coupled to AP-MALDI for high-sensitivity analysis of neuropeptides extracted from Aedes aegypti mosquito heads. The theme of exploring efficient and reproducible purification methods for complex biosamples is continued in Chapter 3, where an evaluation of new on-tip solid-phase extraction (SPE) micro columns with various functional groups is presented. A second approach for enhancing AP-MALDI sensitivity by constructing a new pneumatically-assisted (PA) AP-MALDI ion source is presented in Chapter 4, where various factors affecting the performance of this device are investigated. Chapter 5 describes work involving the evaluation of DART ionization as a high-throughput method for the detection and identification of small terpene molecules central to the Aedes aegypti mosquito lifecycle.
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營利與非營利虛擬社群的管理議題—以維基百科、Yahoo!奇摩知識+為例羅時瀚 Unknown Date (has links)
隨著網路科技的發展,地域化的障礙被打破,人們透過網路獲得許多以往難以獲得的資訊使得消費者意識抬頭,人們也懂得利用網路的力量集結各地消費者向廠商提出要求,許多廠商也願意充分的與消費者溝通,甚至與消費者共同開發,亦即「價值共創」的概念。同樣的,網路將許多有著共同興趣、目標的人群集結在一起,建立許多社群,虛擬社群因而興起。隨著開放原始碼的成功,顯示「價值共創」與「虛擬社群」兩個概念結合的成功案例。本研究即討論兩個結合「價值共創」與「虛擬社群」概念的個案,藉以探討下列兩個問題:
1.營利/非營利、進入門檻及三權假說分別如何影響創新經驗環境?
2.營利/非營利、進入門檻及三權假說與共創平台環境要素DART(溝通、取用、風險評估、透明)的關係為何?
研究發現顯示,營利/非營利扮演一個決定進入門檻設定的因素,進入門檻則會影響三權中管理權下授的問題,三者之間形成一個決策的連鎖反應。
進入門檻同時也會影響DART中的風險評估,不同的進入門檻篩選進不同特性的使用者,使用者的特性會影響其對風險評估的認知程度。其餘的溝通、取用及透明則與營利/非營利、進入門檻及三權假說較無顯著的關聯。
從個案中也瞭解到,即使社群存在許多不利於使用者的因素,但只要內容及運作方式設計良好,仍然可以吸引大量的使用者,驗證了「取用」的概念。但是使用者參與的深度仍會受到影響。
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Application of molecular markers in selected breeding material and plant genetic resources of Lolium perenne L.Liu, Siyang 12 May 2015 (has links)
No description available.
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Evaluating the feasibility of implementing direct analysis in real time - mass spectrometry for the forensic examination of post-blast debrisLising, Ariel 13 July 2017 (has links)
Improvised explosive devices (IEDs) continue to be a national threat to the safety and security of the public. Research in explosives analysis for intact and post-blast samples continue to be a topic in which practitioners are constantly improving and searching for faster methods and techniques to analyze these sample types. The key role crime laboratories play in analyzing these sample types can have limitations, such as increasing turnaround times and backlogs. This concern additionally plays a role in the safety of the public if an unknown individual has not been discovered. Current analytical instrumentation in which explosives are analyzed includes Gas Chromatography – Mass Spectrometry (GC-MS), Liquid Chromatography – Mass Spectrometry (LC-MS), and Ion Mobility Spectrometry (IMS). Each instrument has benefits in the analytical results obtained.
Direct Analysis in Real Time - Mass Spectrometry (DART-MS) has shown a significant promise as an analytical approach that can help remedy the time an explosive sample is analyzed, while additionally providing discriminating analytical results. Previous research has shown that DART-MS is capable of analyzing explosives, including smokeless powder. A limitation currently in the area of smokeless powder analysis with DART-MS is the application of utilizing this method and technology to realistic casework that may be encountered in forensic laboratories. Intact and post-blast explosive samples encountered in forensic laboratories arrive in various states and conditions. For example, the severity of the blast and environmental factors may play a role in the detection of smokeless powder on these sample types.
To provide objective information and additional research, studies were conducted with mixture samples of smokeless powder and potential matrices that may be encountered in real world case samples. Faster processing time, in addition to the discrimination of smokeless powder, was the ultimate goal of this research. Due to the complexity of the mass spectra that may be generated from sample mixtures, an extraction technique coupled with DART-MS was investigated. A liquid-liquid extraction (LLE) method and dynamic headspace concentration using Carbopack™ X coated wire mesh were tested for the effectiveness of separating the analytes of interest of smokeless powder from various matrix interferences. Hodgdon Hornady LEVERevolution (HHL) smokeless powder, Pennzoil 10W-40 (P10W40) motor oil, and residue from metal end caps (China SLK brand) and black steel pipe nipples (Schedule 40) were used during the course of the matrix interference study.
The method of applying dynamic headspace concentration using Carbopack™ X coated wire mesh and analysis by DART-MS provides an effective alternative to obtaining mass spectral data in a shorter amount of time, compared to techniques currently used in forensic laboratories. Effective separation was not achieved using the various LLE methods tested. Further testing would be required in order to evaluate the feasibility of implementing the technique as a sample preparation approach prior to analysis by DART-MS.
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OS Google Chrome - teorie a praxe / OS Google Chrome - theory and practiceDorn, Michal January 2017 (has links)
Thesis deals with the operating system Google Chrome. First, the system is described (how it works, its user interface). Next there is a characteristic of applications that can be downloaded to the system and how they work. Another part is devoted to security, which consists of several elements. The end of the theoretical part is focused on Chromebooks - devices in which the operating system is sold on the market.
The practical part is firstly characterized Dart programming language, which is then used for an application. This application shows not only work with the language, but also the benefits of Google Apps. It also shows compatibility with Windows and compares these two systems.
In conclusion are described advantages and disadvantages of Chrome system and summarizes all knowledge arising from this work.
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Metody pro hodnocení životaschopnosti Xanthomonas euvesicatoria po ošetření nízkoteplotním plazmatem / Methods for viability evaluation of Xanthomonas vesicatoria after low temperature plasma treatmentZEMANOVÁ, Marta January 2017 (has links)
The thesis deals with methods for viability evaluation of the phytopathogenic bacterium Xanthomonas euvesicatoria after low-temperature plasma treatment. Low-temperature plasma produced by Gliding Arc experimental device was used for treatment of X. euvesicatoria. The viability of the bacterial cells was assessed using a scanning electron microscope (SEM) and by measuring of the fluorescence in the Smart-DART device using PrestoBlue chemical reagent. Methodology has been optimised for the sample preparation for the treatment by low temperature plasma and used for evaluation of applied methods. Lethal effect of gliding arc plasma to this gram-negative bacteria was verified by SEM which showed. There is significant structural changes on the cell surface. Viability assessment of X. euvesicatoria using Smart-DART device is a fast, time-saving and inexpensive evaluation of cell viability. The great advantage of this device is its ability to measure the fluorescence in real time. The disadvantage of this method is lower reliability in current stage of research.
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Genetická diverzita a fylogeneze Pisum fulvum Sibth. & Sm.Trněný, Oldřich January 2016 (has links)
Pisum fulvum Sibth. & Sm. is one of the three species in genus Pisum L., which also includes species Pisum sativum L. and Pisum abyssinicum A.Br. P. fulvum together with subspecies P. sativum subsp. elatius M.Bieb. and P. sativum subsp. humile Boiss. et Noe. belong to the group of wild pea. P. fulvum belongs to secondary gene pool of cultural pea P. sativum L. subsp. sativum. Due to the potential use of P. fulvum as a donor of gene of interest in processes of cultural pea genetic diversity enrichment, it may be considered as an important plant species whose biological characteristics should be assembled within the possibilities. Divergence separating P. fulvum from the rest of the evolutionary lineage of the genus Pisum occured in the period before 1.7 million years +/- 0.4 million years. Currently, its habitats is limited to the eastern part of the territory of Levant where P. fulvum is more abundant plant in its range than other groups of the genus Pisum that occurs sympatric with P. fulvum. The genetic diversity of P. fulvum is characterized in the current thesis by three approaches of molecular biology using DNA sequencing of ITS nuclear region and trnSG chloroplast region, DArT-SeqTM and GenoPea 13.2km SNP. Sequencing ITS region of 149 accessions led to the identification of four ribotypes that were analyzed in biogeographical context. Based on the comparing the analysis of data from genome-wide genotyping DArT-SeqTM and origin of analyzed accessions three groups (south, central and north) which can be considered as intraspecific evolutionary line were identified. In case of analysis of data from GenoPea 13.2K SNP P. fulvum genotype was compared with genotypes of other groups of pea and P. fulvum asociated SNPs were identified. Recent gene flow between some accessions of P. fulvum and accessions of other groups of wild pea was confirmed by analysis of codominant SNP data and by analysis of trnSG sequences.
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E-dart : um ambiente de especificação e-lotos / E-DART - an E-LOTOS specification environmentGranville, Lisandro Zambenedetti January 1998 (has links)
O aumento crescente da complexidade dos sistemas computacionais criou a necessidade do uso de técnicas de descrição formal (TDFs) na definição, implementação e manutenção dos sistemas. Contudo, apenas a existência de técnicas de descrição formal não garante o eficiente emprego das mesmas na especificação dos sistemas. É necessária a existência de ferramentas que viabilizem o uso das TDFs de forma que estas possam ser efetivamente úteis no desenvolvimento de projetos. Este trabalho apresenta os resultados obtidos da construção de um ambiente de especificação gráfico, onde a TDF E-LOTOS (Enhancements to LOTOS) fornece os mecanismos que uma técnica de descrição deve possuir para viabilizar a consistência, verificação e validação de sistemas. A TDF é suportada através do emprego de uma nova versão gráfica para a sintaxe textual padrão de E-LOTOS. O principal objetivo deste trabalho é disponibilizar aos projetistas e desenvolvedores um ambiente de especificação onde a criação, implementação, teste e manutenção de sistemas sejam feitos de forma fácil, rápida, intuitiva e consistente. Para tal, uma nova sintaxe gráfica de E-LOTOS foi criada: o E-DART (Enhancements to DART). Foi desenvolvida também uma ferramenta que permite o uso de E-DART, o Editor E-DART. A nova sintaxe abstrai, através de diagramas, as complexidades naturais de E-LOTOS, permitindo uma compreensão mais intuitiva dos sistemas. Com o uso de E-DART as especificações construídas são validadas por uma TDF sem que o processo de criação torne-se complexo. No Editor E-DART, a rapidez na criação das especificações é alcançada com mecanismos de reuso de módulos, e com o emprego de recursos avançados de interação com o usuário. O reuso de módulos diminui o tempo total dispensado na criação de especificações porque as mesmas poderão utilizar partes já homologadas de outros sistemas, sem a necessidade de validação e testes, pois estes são procedimentos realizados anteriormente nas outras especificações. Os recursos avançados de interação, por outro lado, permitem que projetistas não familiarizados com E-LOTOS sejam ainda assim capazes de construir sistemas complexos. Além disso, profissionais que tenham experiência com a TDF têm acesso direto ao código textual E-LOTOS, o que lhes garante uma maior compreensão das especificações. / The increasing complexity of the computational systems has created the necessity of the use of formal description techniques (FDTs) in the systems definition, implementation and maintenance. However, only the existence of formal description techniques does not guarantee their efficient use in the systems specification. The existence of tools is necessary to make the use of the TDFFs possible in a way in which these techniques can be effectively useful in projects development. This work presents the results of the construction of a specification graphical environment, where E-LOTOS FDT (Enhancements to LOTOS) supplies the mechanisms that a description technique must possess to make possible the consistency, verification and validation of systems. The FDT is supported through the use of a new graphical version for the standard textual E-LOTOS syntax. The main goal of this work is to provide to designers and developers a specification environment where the creation, implementation, test and maintenance of systems are made in a easy form, fast, intuitive and consistent way. For such, a new graphical syntax of E-LOTOS was created: the E-DART (Enhancements to DART). A tool that allows the E-DART use was also developed, the E-DART Editor. The new syntax represents, through diagrams, the natural complexities of E-LOTOS, allowing a intuitive understanding of the systems. With the use of E-DART the specifications are still validated by a FDT, without turning their creation into a complex process. In the E-DART Editor, fast creation of the specifications is achieved with mechanisms of module reuse, and with the use of advanced user interaction resources. The reuse of module diminishes the total time used in the specifications creation because it will be possible to use parts already validated of other systems. The advanced interaction resources, on the other hand, allow that designers not familiarized with E-LOTOS to be able to construct complex systems. Moreover, professionals who have experience with the FDT have direct access to textual ELOTOS code, which guarantees an easier understanding of the specifications.
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