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Comparing Well-Defined Manganese, Iron, Cobalt, and Nickel Ketone Hydrosilylation Catalysts

Description

A brief review of manganese-catalyzed hydrosilylation is presented along with a personal account of how the design for the highly active catalyst, (^Ph2PPrPDI)Mn, was conceived. The reductive transformations achieved using this catalyst are described and put into further context by comparing the observed activities with those attained for leading late…

A brief review of manganese-catalyzed hydrosilylation is presented along with a personal account of how the design for the highly active catalyst, (^Ph2PPrPDI)Mn, was conceived. The reductive transformations achieved using this catalyst are described and put into further context by comparing the observed activities with those attained for leading late first-row transition-metal catalysts.

ContributorsTrovitch, Ryan (Author) / Department of Chemistry and Biochemistry (Contributor)

Created2014-07-01

Multiplexed Single-Cell In Situ RNA Analysis by Reiterative Hybridization

Description

Most current approaches for quantification of RNA species in their natural spatial contexts in single cells are limited by a small number of parallel analyses. Here we report a strategy to dramatically increase the multiplexing capacity for RNA analysis in single cells in situ. In this method, transcripts are detected…

Most current approaches for quantification of RNA species in their natural spatial contexts in single cells are limited by a small number of parallel analyses. Here we report a strategy to dramatically increase the multiplexing capacity for RNA analysis in single cells in situ. In this method, transcripts are detected by fluorescence in situ hybridization (FISH). After imaging and data storage, the fluorescence signal is efficiently removed by photobleaching. This enables the reinitiation of FISH to detect other RNA species in the same cell. Through reiterative cycles of hybridization, imaging and photobleaching, the identities, positions and copy numbers of a large number of varied RNA species can be quantified in individual cells in situ. Using this approach, we analyzed seven different transcripts in single HeLa cells with five reiterative RNA FISH cycles. This approach has the potential to detect over 100 varied RNA species in single cells in situ, which will have wide applications in studies of systems biology, molecular diagnosis and targeted therapies.

ContributorsXiao, Lu (Author) / Guo, Jia (Author) / Department of Chemistry and Biochemistry (Contributor)

Created2015-04-29

Physical-Chemical Characterisation of the Particulate Matter Inside Two Road Tunnels in the São Paulo Metropolitan Area

Description

The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and…

The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by heavy duty vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM_2.5 concentration was on average 52 μg m^-3, with the largest contribution of organic mass (OM, 42%), followed by elemental carbon (EC, 17%) and crustal elements (13%). Sulphate accounted for 7% of PM_2.5 and the sum of other trace elements was 10%. In the RA tunnel, PM_2.5 was on average 233 μg m^-3, mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1%, and 1%, respectively. The average OC : EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC : EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel-fuelled HDVs. Besides bulk carbonaceous aerosol measurement, polycyclic aromatic hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m^-3 and 45 ± 9 ng m^-3 in the RA and JQ tunnel, respectively. In the JQ tunnel, benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m^-3 (0.02–0.1‰ of PM_2.5)] whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m^-3 (0.004–0. 02‰ of PM_2.5), indicating an important relative contribution of LDVs emission to atmospheric BaP.

ContributorsBrito, J. (Author) / Rizzo, L. V. (Author) / Herckes, Pierre (Author) / Vasconcellos, P. C. (Author) / Caumo, S. E. S. (Author) / Fornaro, A. (Author) / Ynoue, R. Y. (Author) / Artaxo, P. (Author) / Andrade, M. F. (Author) / Department of Chemistry and Biochemistry (Contributor)

Created2013-12-17

Room Temperature Structures Beyond 1.5 Å by Serial Femtosecond Crystallography

Description

About 2.5 × 10⁶ snapshots on microcrystals of photoactive yellow protein (PYP) from a recent serial femtosecond crystallographic (SFX) experiment were reanalyzed to maximum resolution. The resolution is pushed to 1.46 Å, and a PYP structural model is refined at that resolution. The result is compared to other PYP models determined…

About 2.5 × 10⁶ snapshots on microcrystals of photoactive yellow protein (PYP) from a recent serial femtosecond crystallographic (SFX) experiment were reanalyzed to maximum resolution. The resolution is pushed to 1.46 Å, and a PYP structural model is refined at that resolution. The result is compared to other PYP models determined at atomic resolution around 1 Å and better at the synchrotron. By comparing subtleties such as individual isotropic temperature factors and hydrogen bond lengths, we were able to assess the quality of the SFX data at that resolution. We also show that the determination of anisotropic temperature factor ellipsoids starts to become feasible with the SFX data at resolutions better than 1.5 Å.

ContributorsSchmidt, Marius (Author) / Pande, Kanupriya (Author) / Basu, Shibom (Author) / Tenboer, Jason (Author) / Department of Chemistry and Biochemistry (Contributor)

Created2015-05-15

Probabilistic Modeling and Regression Analysis of Experimental Data for Structural Systems

Description

The Experimental Data Processing (EDP) software is a C++ GUI-based application to streamline the process of creating a model for structural systems based on experimental data. EDP is designed to process raw data, filter the data for noise and outliers, create a fitted model to describe that data, complete a…

The Experimental Data Processing (EDP) software is a C++ GUI-based application to streamline the process of creating a model for structural systems based on experimental data. EDP is designed to process raw data, filter the data for noise and outliers, create a fitted model to describe that data, complete a probabilistic analysis to describe the variation between replicates of the experimental process, and analyze reliability of a structural system based on that model. In order to help design the EDP software to perform the full analysis, the probabilistic and regression modeling aspects of this analysis have been explored. The focus has been on creating and analyzing probabilistic models for the data, adding multivariate and nonparametric fits to raw data, and developing computational techniques that allow for these methods to be properly implemented within EDP. For creating a probabilistic model of replicate data, the normal, lognormal, gamma, Weibull, and generalized exponential distributions have been explored. Goodness-of-fit tests, including the chi-squared, Anderson-Darling, and Kolmogorov-Smirnoff tests, have been used in order to analyze the effectiveness of any of these probabilistic models in describing the variation of parameters between replicates of an experimental test. An example using Young's modulus data for a Kevlar-49 Swath stress-strain test was used in order to demonstrate how this analysis is performed within EDP. In order to implement the distributions, numerical solutions for the gamma, beta, and hypergeometric functions were implemented, along with an arbitrary precision library to store numbers that exceed the maximum size of double-precision floating point digits. To create a multivariate fit, the multilinear solution was created as the simplest solution to the multivariate regression problem. This solution was then extended to solve nonlinear problems that can be linearized into multiple separable terms. These problems were solved analytically with the closed-form solution for the multilinear regression, and then by using a QR decomposition to solve numerically while avoiding numerical instabilities associated with matrix inversion. For nonparametric regression, or smoothing, the loess method was developed as a robust technique for filtering noise while maintaining the general structure of the data points. The loess solution was created by addressing concerns associated with simpler smoothing methods, including the running mean, running line, and kernel smoothing techniques, and combining the ability of each of these methods to resolve those issues. The loess smoothing method involves weighting each point in a partition of the data set, and then adding either a line or a polynomial fit within that partition. Both linear and quadratic methods were applied to a carbon fiber compression test, showing that the quadratic model was more accurate but the linear model had a shape that was more effective for analyzing the experimental data. Finally, the EDP program itself was explored to consider its current functionalities for processing data, as described by shear tests on carbon fiber data, and the future functionalities to be developed. The probabilistic and raw data processing capabilities were demonstrated within EDP, and the multivariate and loess analysis was demonstrated using R. As the functionality and relevant considerations for these methods have been developed, the immediate goal is to finish implementing and integrating these additional features into a version of EDP that performs a full streamlined structural analysis on experimental data.

ContributorsMarkov, Elan Richard (Author) / Rajan, Subramaniam (Thesis director) / Khaled, Bilal (Committee member) / Chemical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Ira A. Fulton School of Engineering (Contributor) / Barrett, The Honors College (Contributor)

Created2016-05

Joseph Rotblat, the Physicist Who Left the Manhattan Project: a Biography of Scientific Responsibility

Description

Joseph Rotblat (1908-2005) was the only physicist to leave the Manhattan Project for moral reasons before its completion. He would spend the rest of his life advocating for nuclear disarmament. His activities for disarmament resulted in the formation, in 1957, of the Pugwash conferences, which emerged as the leading global…

Joseph Rotblat (1908-2005) was the only physicist to leave the Manhattan Project for moral reasons before its completion. He would spend the rest of his life advocating for nuclear disarmament. His activities for disarmament resulted in the formation, in 1957, of the Pugwash conferences, which emerged as the leading global forum to advance limits on nuclear weapons during the Cold War. Rotblat's efforts, and the activities of Pugwash, resulted in both being awarded the Nobel Peace Prize in 1995. Rotblat is a central figure in the global history of resistance to the spread of nuclear weapons. He also was an important figure in the emergence, after World War II, of a counter-movement to introduce new social justifications for scientific research and new models for ethics and professionalism among scientists. Rotblat embodies the power of the individual scientist to say "no" and thus, at least individually, put limits of conscience on his or her scientific activity. This paper explores the political and ethical choices scientists make as part of their effort to behave responsibly and to influence the outcomes of their work. By analyzing three phases of Rotblat's life, I demonstrate how he pursued his ideal of beneficial science, or science that appears to benefit humanity. The three phases are: (1) his decision to leave the Manhattan Project in 1944, (2) his role in the creation of Pugwash in 1957 and his role in the rise of the organization into international prominence and (3) his winning the Nobel Peace Prize in 1995. These three phases of Rotblat's life provide a singular window of the history of nuclear weapons and the international movement for scientific responsibility in the 50 years since the bombing of Hiroshima in 1945. While this paper does not provide a complete picture of Rotblat's life and times, I argue that his experiences shed important light on the difficult question of the individual responsibility of scientists.

ContributorsEvans, Alison Dawn (Author) / Zachary, Gregg (Thesis director) / Hurlbut, Ben (Committee member) / Francis, Sybil (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)

Created2015-05

Perceived Ratio of Vegetable to Fruit in Juice Diets: A Case Study of the Online Juicing Population

Description

The purpose of this study was to determine the ratio of vegetable to fruit incorporated during a fresh vegetable and/or fruit juice diet. Juicing is the process of extracting the liquid part of a plant, fruit, or vegetable. Food can be ground, pressed, and spun to separate the liquid from…

The purpose of this study was to determine the ratio of vegetable to fruit incorporated during a fresh vegetable and/or fruit juice diet. Juicing is the process of extracting the liquid part of a plant, fruit, or vegetable. Food can be ground, pressed, and spun to separate the liquid from the pulp. A juice diet involves juicing and consuming a variety of vegetables and fruits. The primary objective of this study was to gather information about the ratio of vegetable to fruit incorporated in freshly made juices during a juice diet. Therefore, the study survey inquired about various topics related to ingredient ratio during a juice diet. The survey data allowed for examination of the relationships between ingredient ratio and certain variables (e.g. gender, age, length of time juicing, juice fast participation, health effects, etc.). The study participants were recruited using online social media. Facebook was the primary method for reaching the online juicing community. A written invitation was distributed in several health related Facebook groups encouraging any person with experience juicing to complete an anonymous survey. This post was also shared via Twitter and various health related websites. The study survey data was used to examine the relationships between ingredient ratio and specific variables. The survey data showed participants had varying levels of experience with juicing. The responses indicated many participants were familiar with juice fasting and many participants completed more than one juice fast. Based on the survey response data, the most common ratio of vegetable to fruit incorporated by the participants during a juice diet was 80% vegetable to 20% fruit. The majority of participants indicated daily consumption of freshly made juice containing 70% -100% vegetables. Based on the survey response data, beginner juicers may be less inclined to incorporate organic produce into their juice diet compared to advanced juicers. The majority of participants reported positive health benefits during a juice diet. Some of the positive health benefits indicated by participants include weight loss, increased energy, and a positive impact on disease symptoms. Some of the negative side effects experienced by participants during a juice diet include frequent urination, headache, and cravings. Cross tabulation calculations between the ratio of ingredients and several variables covered by the study survey demonstrated statistical significance (i.e. length of time juicing, frequency of drinking juice, juice fast participation, number of juice fasts completed, servings of vegetables/fruit in a juice, percent of organic vegetables/fruit used in a juice, perceived positive side effects, and perceived negative side effects). This study provided insight about the average ratio of vegetable to fruit incorporated by participants during a juice diet. When analyzing the data it is important to consider the survey data was self-reported. Therefore, every result and conclusion is based on the individual perceptions of the study participants. In future experimentation, the use of medical tests and blood work would be useful to determine the biological and biochemical effects of drinking raw vegetable and/or fruit juice on the human body.

ContributorsMata, Sara Ann (Author) / Mayol-Kreiser, Sandra (Thesis director) / Shepard, Christina (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor)

Created2015-05