Since the tragedy of the drug Thalidomide® in the late 1950 to early 1960’s, chirality has been recognized as an important aspect that must be controlled in the drug development process in the pharmaceutical industry. Since then, there has been a considerable movement towards single enantiomer drugs. This demand has presented many challenges for the synthetic organic chemist. Chiral catalysts offer one solution to this problem, as they afford the unique ability to preferentially synthesize one enantiomer. Unfortunately, the design of new chiral catalysts is often empirical, with luck and trial and error necessary due to factors that govern enantioselectivity. Therefore, it would be highly beneficial to develop a method that is capable of screening multiple chiral catalysts early in the catalyst development cycle. Using a modified ion-trap mass spectrometer, the chiral environment of various chiral catalysts may be examined, free from solvent and ion-pairing affects. Thus, the catalyst’s inherent asymmetric environment (enantioselectivity) may be probed using simple chiral molecules, including alcohols, ethers, and epoxides of various steric demands. Using these probes, various C2-symmetric bis-oxazolines and di-imines catalysts were examined. Use of the binaphthyl-based diamine, BINAM, condensed with various 3,5-disubstituted benzaldehydes, provided selectivity close to the privileged catalyst, bis-oxazoline. In general, the chiral probes 1-phenyl-2-propanol, 1-mehtoxyethylbenzene, and styrene oxide offer the best look at the catalyst’s enantioselectivity potential. With the use of the ion-trap mass spectrometer as a mass filter, the purity of the catalyst is not paramount, thus, multiple catalysts may be screened simultaneously, with the constraint that the catalysts must be of different m/z. This thesis presents results found during the exploration of various C2 and C1-symmetric chiral catalysts, in the development of the new chiral screening method utilizing various chiral probes.

No description available.

D.L. A 1165-2006

Neste trabalho desenvolveu-se uma metodologia analítica para determinação do teor de trialometanos THMs em amostras de águas potáveis, utilizando a técnica de purga e armadilha acoplada à cromatografia a gás (GCPT). Os THMs são subprodutos da cloração da água que devem possuir um limite máximo de 100 μg.L-1 segundo a legislação brasileira, estes compostos são suspeitos carcinogênicos humanos com base em estudos em animais de laboratório. A técnica de purga e armadilha extrai eficientemente estes compostos da água e a separação no cromatógrafo a gás ocorre utilizando coluna de leve polaridade e detector por captura de elétrons. Este detector é seletivo e o mais sensível para estes compostos halogenados. A metodologia desenvolvida foi validada nos itens de: linearidade, seletividade, exatidão, precisão, limite de quantificação, limite de detecção e robustez. O limite de detecção para os THMs foi menor do que 0,5 μg.L-1. A exatidão e precisão foram adequadas para ensaios de compostos traços. As amostras de água potável foram coletadas na cidade de Suzano-SP, que pertence à região do Alto do Tietê, nesta região nas margens do rio a vegetação é predominante. Entre todos os THMs, o composto encontrado na água potável em maiores concentrações foi o clorofórmio onde os resultados quantitativos, utilizando esta metodologia apresentaram teores entre 15,9 à 111,0 μg.L-1 em águas potáveis. / This work shows an analytical methodology developed and optimized to determine trihalomethanes level THMs, in drinking water samples, using purge and trap coupled to gas chromatography (GC-PT). THMs are byproducts water chlorination, these compounds must have a maximum of 100 μg.L-1 under Brazilian law, due these compounds be suspected human carcinogens base on studies in laboratory animals. The technique of purge and trap efficiently extracts these compounds from water, and the gas chromatograph separates the THMs. The GC uses a light polarity column and electron capture detector. This detector is selective and more sensitive in the detection of these compounds. The methodology was validated in terms of: linearity, selectivity, accuracy, precision, quantification limit, detection limit and robustness. The detection limit was less than 0,5 μg.L-1. The accuracy and precision were adequate for testing the trace compounds. The drinking water samples were collected in the city of Suzano-SP, which belongs to Alto do Tietê, in this region lay Tietê river with predominant vegetation. The THMs compound found in drinking water at higher concentrations was chloroform where the spread of values found between 15,9 to 111,0 μg.L-1 in drinking water.

Management of pest species is ordinarily required in the production of protected crops. Integrated pest management (IPM) is commonly used when controlling insects. The European Union Sustainable Use Directives states that "integrated pest management’ means careful consideration of all available plant protection methods and subsequent integration of appropriate measures that discourage the development of populations of harmful organisms and keep the use of plant protection products and other forms of intervention to levels that are economically and ecologically justified and reduce or minimise risks to human health and the environment. ‘Integrated pest management’ emphasises the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms.” Effectively monitoring pests is a key component of IPM, with decisions to use biological control agents (BCA) and insecticides often based on the presence of pests in traps. A commonly used monitoring tool is the sticky trap; these traps are coloured and rely primarily on their visual attractiveness to the pest. The capture efficiency of sticky traps can potentially be increased with the addition of light emitting diodes (LEDs). The objective of this project was to use LEDs to enhance the efficacy of yellow sticky traps for trapping a range of insect pests, to enable more effective timing of pest management by optimising pest monitoring. The addition of LEDs may also enable more effective mass trapping via yellow sticky traps, and minimize the trapping of beneficial insects. Comparisons between standard yellow sticky traps and those equipped with green (540 nm) or blue (480 nm) LEDs were carried out at four commercial growing facilities. Green (540 nm) LED equipped traps were compared with standard yellow traps in a mass release of the biological control agent Encarsia formosa Gahan (Hymenoptera: Aphelinidae), to determine if there are negative consequences to the addition of green (540 nm) LEDs when using this biological control agent. Relative spectral preferences of western flower thrips (Frankliniella occidentalis Pergande (Thysanoptera: Thripidea)) and Glasshouse whitefly (Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae)) were determined using a choice test comparing a range of wavelengths in 20 nm steps against a control wavelength. Green (540 nm), and blue (480 nm) LED equipped traps captured significantly more dark-winged fungus gnats (Bradysia difformis Frey (Sciaridae: Diptera)) and diamondback moths (Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae)) than those without. No significant differences were found between green (540 nm) LED equipped traps and those without for E. formosa, and a significant decrease in the capture of the shore fly parasitoid Kleidotoma psiloides Westwood (Hymenoptera: Figitidae) was observed. In behavioural experiments F. occidentalis showed a peak spectral preference at 360, 420, and 480 nm, and T. vaporariorum at 320, 340, and 380 nm. The addition of LEDs to yellow sticky traps enhanced their capture efficiency for some key pests in commercial protected crop growing environments, and has the potential to enable pest detection at an early stage, consequently optimising the timing of pest management options.

Uma das abelhas solitárias sugeridas para programas de polinização controlada foi Centris analis, pela constância e abundância no Brasil. Estudos mostraram a importância de C. analis na polinização de algumas culturas agrícolas, e vários trabalhos trazem informações a respeito da sua biologia. No entanto, ainda faltam informações a respeito de fatores capazes de aumentar ou diminuir a população de C. analis. Assim ninhos-armadilha confeccionados com cartolina foram oferecidos no campus da Universidade de São Paulo Ribeirão Preto, com dimensões de 0,6cm de diâmetro e em quatro comprimentos diferentes (6, 7, 8 e 9cm), de outubro de 2010 a setembro de 2012. Resultando em 500 ninhos de onde emergiram 369 fêmeas e 562 machos de C. analis, a mortalidade ocorreu em decorrência dos parasitas Leucospis sp. (100), Coelioxys sp. (55), Anthrax sp (3), por causa de fungos (107) e por causas desconhecidas (100). Ninhos-armadilha de 6 e 7cm apresentaram até quatro células, já os ninhos de 8 e 9cm apresentaram até seis células, sendo os ninhos de 8cm os mais utilizados. A razão sexual apresentou-se desviada para machos e os resultados indicam que o comprimento dos ninhos-armadilha não foi capaz de influenciar a razão sexual dessa abelha. Fêmeas de C. analis que nidificaram entre outubro de 2010 a abril de 2012 foram monitoradas (n=28) quanto ao seu comportamento na área; a atividade delas variou de 6 a 24 dias. Cinco fêmeas apresentaram comportamento considerado diferente do padrão e foram coletadas para dissecção, apresentando uma larva parasitoide em seu abdômen. Três delas fizeram depósitos adicionais de óleo em ninhos terminados dias antes, e normalmente não recebem mais materiais; as outras duas fêmeas foram coletadas após fazerem um falso fechamento, quando fecham a entrada do ninho-armadilha sem construir células de cria nele. As cinco fêmeas construíram ninhos convencionais nos primeiros dias de monitoramento, mas cessaram a construção de ninhos com células de cria e passaram a realizar os comportamentos atípicos. Esses comportamentos sugerem que as fêmeas tornam-se estéreis conforme a larva parasitoide cresce, primeiramente pela perda do espaço para transportar néctar para o ninho, e depois pela perda dos órgãos internos. Antes de morrer várias C. analis, machos e fêmeas, ocultaram-se dentro dos ninhos-armadilha, possivelmente por influência do parasitoide. C. analis encontradas mortas tem sido recolhidas de janeiro de 2008 a setembro de 2012, totalizando 186 abelhas mortas, de onde emergiram 113 conopideos adultos, pertencentes a oito espécies. A maioria foi encontrada nos três primeiros meses do ano, período de maior atividade dos hospedeiros. Assim, conclui-se que somente o comprimento dos ninhos-armadilhas utilizados não é capaz de influenciar a razão sexual da prole; as mortes nos ninhos ocorre principalmente pelos ataques de Leucospis sp., por fungos ou por causas desconhecidas, e um importante inimigo natural dos adultos são os conopideos. / One of the solitary bees suggested to programs of controlled pollination was Centris analis, because of its constancy and abundance in Brazil. Several studies have shown the importance of C. analis in the pollination of some crops, and some papers brought information on the biology of this species. However, it still lacks information about factors that can increase or decrease C. analis population. Hence trap-nests made of black cardboard were offered in the campus of Universidade de São Paulo Ribeirão Preto from October of 2010 to September of 2012. The trap-nests measured 0.6cm in internal diameter and 6, 7, 8 and 9cm in length. Five hundred nests were obtained during the study period. From these nests emerged 369 females and 562 males of C. analis, and the immature mortality occurred due the parasites Leucospis sp. (100), Coelioxys sp. (55), Anthrax sp. (3), probably fungi (107) and unknown causes (100). Trap-nests with 6 and 7cm had up to four cells, and nests with 8 and 9cm had up to six cells, the most used length of trap-nest was 8cm. Sex ratio was male biased, and it seems that the trap-nests lengths did not influence the sex ratio of this bee. Twenty-eight females of C. analis were monitored during their nesting activities that occurred from October 2010 to April 2012. These females worked in the trap-nests from 6 to 24 days. Five females showing behavior considered different from normal pattern had a parasitoid larva inside their abdomen. Three of them made additional deposits of oil on nests finished days before, which usually dont receive more materials; the other two females were collected after making a fake nest plug, when they close the nest entrance without building brood cells in it. The five females built normal nests during the first days of monitoring, but stopped building nests with brood cells and started to make behaviors considered as atypical. These behaviors suggest that females become sterile as the parasitoid larva grows, first because the loss of space to carry nectar to the nest, and later because the loss of internal organs. Before dying many C. analis, males and females, concealed themselves inside trap-nests, possibly by influence of the parasitoid. The dead bees found inside trap-nests have been collected from January 2008 to September 2012, totaling 186 bees, from where emerged 113 adult conopids, belonging to eight species. Most of them were found in the three first months of the year, period of the hosts higher activity. Therefore, the conclusion is that the lengths of trap-nests alone do not influence the brood sex ratio; mortality in nests occurred mainly because of Leucospis sp. attacks, fungi or unknown causes, and an important natural enemy of the adults C. analis are the conopids.

Developing portable mass spectrometry systems is an active area of research due to its broad range of useful applications, including environmental monitoring, threat detection, and space exploration. The mass analyzer is one of the key elements of the mass spectrometry system to develop for a portable system. Ion traps are a good candidate for the mass analyzer in a portable mass spectrometry system because the operating pressure scales with size. This allows for scaling down the other components of the system including the vacuum and electrical systems. Researchers at BYU are making an effort to develop miniature ion traps based on a planar geometry. The ion traps are made using microfabrication processes. A summary of the plates developed at BYU is presented in this work. Results from experiments to test the effects of pitch alignment on one design of planar ion trap plates are also presented. Conventional ion traps use a sinusoidal waveform to drive them. Driving the ion trap with a digital waveform has many benefits including extended mass range, lower voltage, and more control over the waveform. One of the difficulties involved in using a digital waveform is creation of a high voltage, high frequency waveform. This work details the design of a digital circuit capable of outputting a waveform with an amplitude of 100 VP-P at a frequency of 5 MHz and lower. This waveform was applied to a new ion trap design based on wire electrodes instead of planar electrodes. This trap offers many benefits over the planar ion traps developed at BYU. This work presents mass spectra obtained using a square digital waveform applied to the wire ion trap.

L’ADN et l’ARN double brin (ADNdb, ARNdb) subissent des transitions de surétirement avec des forces d’environ 60 pN. Nous effectuons des mesures de force à l'aide d'un piège optique à double faisceau contenant deux billes reliées par une seule molécule. Un brin du duplex est attaché aux deux extrémités aux deux billes, tandis que l’autre brin n’est attaché qu’à une seule extrémité. Quatre cas différents sont comparés: ADNdb, ARNdb, hybride ARN- ADN avec ADN sous tension et hybride ADN- ARN avec ARN sous tension.Un surétirement se produit pour les quatre duplex. La différence la plus remarquable est que les ARNdb présentent un plateau lisse, alors que les autres duplex présentent des motifs en dents de scie. Nous constatons que les ARNdb s'étirent par un mécanisme différent et expliquons pourquoi cette propriété pourrait aider les structures d'ARN à s'assembler et à jouer leurs rôles biologiques.Un surétirement de l'hybride ARN-ADN libère progressivement un brin d'ARN. Les structures formées au sein de cet ARN naissant sont visibles dans le signal de force lors du re- recuit. Pour la première fois à notre connaissance, nous imitons donc et étudions le repliement de l'ARN co-transcriptionnel dans un test in vitro. En se concentrant sur le stade précoce de l’assemblage des grandes sous- unités ribosomales de E. coli (domaines I-II de l’ARNr 23S et des protéines r L4, L13, L20, L22, L24), on observe plus souvent un recuit partiel avec les protéines r. Nos résultats indiquent que les cinq protéines r de liaison précoce agissent comme des auxiliaires de repliement bien avant que l’ARN 23S complet ne soit transcrit. / Double-stranded DNA and RNA (dsDNA, dsRNA) undergo overstretching transitions at forces around 60 pN. We perform force measurements using a dual-beam optical trap that holds two beads linked by a single molecule. One strand of the duplex is attached at both extremities to the beads, while the other strand is attached only at one extremity. Four different cases are compared: dsDNA, dsRNA, RNA-DNA hybrid with DNA under tension, and DNA-RNA hybrid with RNA under tension. Overstretching occurs for all four duplexes. The most remarkable difference is that dsRNA exhibits a smooth plateau, while the other duplexes show saw-tooth patterns. We find that dsRNA overstretches by a different mechanism and explain why this property could help RNA structures to assemble and play their biological roles.Overstretching the RNA-DNA hybrid progressively liberates an RNA strand. Structures formed within this nascent RNA are seen in the force signal upon re-annealing. For the first time to our knowledge, we thus mimic and study co-transcriptional RNA folding in an in-vitro assay. Focusing on the early stage of E.coli large ribosomal subunit assembly (domains I-II of 23S rRNA and r-proteins L4, L13, L20, L22, L24), partial re-annealing is observed more frequently with r-proteins than without. Our results indicate that the five early- binding r-proteins act as folding helpers well before the entire 23S RNA is transcribed.

Onion production in the United States is seriously affected by the tospovirus Iris Yellow Spot (IYSV), whose symptoms include lenticular-shaped lesions that reduce photosynthesis and bulb yield. Thrips tabacai Lindeman, onion thrips (OT), is the only known vector of the disease and a primary arthropod pest of onion. Frequent insecticide applications, increasing resistance in OT populations to insecticides, high nitrogen (N) fertilization rates and loss of yield to disease and insect pressure threaten sustainable onion production. The objectives of this study were to identify crop management strategies to enhance onion productivity while suppressing OT and IYSV. Three fertilizer rates and two crop rotations were assigned to replicated plots to assess effects on onion growth, yield, bulb storage quality, soil quality, thrips populations and IYSV incidence. Trap crops of carrot, buckwheat and lacey phacelia were established in commercial fields to evaluate impact on thrips populations and IYSV occurence. Reduced nitrogen (N) rates, one-third the standard grower rate (133.8 kg N ha-1), resulted in no yield loss as compared with the standard N rate, despite slower crop maturation. Onions treated with a standard N rate(401.8 kg N ha-1) had greater numbers of adult and immature OT than other treatments. Soil nitrate levels were lower and microbial activity measured as dehydrogenase and biomass were greater in reduced N treatments. Plots with buckwheat and phacelia had greater numbers of both adult and immature OT when trap crop apparancy was high (i.e. when onion plants were relatively smaller). There was no observed effect of trap crops on IYSV levels. Results suggest that reduced rate N applications lower numbers of OT while enhancing the microbial population, reducing potential for nitrate leaching while still maintaining yields. Potential for trap crops of buckwheat and lacey phacelia to attract onion thrips from onions exists with successive stands of highly apparent trap crops.

Mass selective axial ejection of ions and mass analysis with a stability island with linear quadrupoles with added octopole fields are described. With mass selective axial ejection, quadrupoles with 2.0% and 2.6% added octopole fields have been tested and compared to a conventional quadrupole. The effects of trapping ions at different q values, excitation voltage, scan direction, balanced and unbalanced rf voltages on the rods, and dc applied between the rods have been investigated. The highest scan speeds and highest resolution are obtained with resonant excitation and ejection at high q (q = 0.8). With axial ejection, the quadrupole with a 2.0% added octopole field provides mass resolution and ejection efficiencies similar to a conventional rod set. Quadrupole, dipole and simultaneous dipole-dipole excitation between the x and y rod pairs were compared and no advantage was found with quadrupole or dipole-dipole excitation. The effects of scan speed were investigated and a resolution at half height of about 1600 is possible at scan speeds up to 5000 Th/s. Mass analysis using islands of stability was investigated with a quadrupole with2.0% added octopole field. The island of stability is formed with auxiliary excitation. The experiments confirm the predictions of the simulations. With the resolving dc applied to the quadrupole so that the Mathieu parameter a>0, conventional mass analysis with applied rf and dc and no auxiliary excitation is possible. In this case use of an island of stability yields similar peak shape and resolution. However with the polarity of the resolving dc reversed so that a<0, only very low resolution can be obtained; the added octopole prevents conventional mass analysis. By using a stability island when a<0, the resolution is substantially improved.