Thesis (M.Phil.) - University of St Andrews, January 2009.

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Orientadores: Vitor Baranauskas, Maria Alice da Cruz-Hofling / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-25T18:03:05Z (GMT). No. of bitstreams: 1 Vieira_WilliansFernando_M.pdf: 6828315 bytes, checksum: caab660e36c10bd15dfb824c4b1a18fe (MD5) Previous issue date: 2014 / Resumo: O tecido muscular é o principal afetado nos acidentes com veneno botrópico. O estudo do uso da luz, por meio da irradiação laser de baixa intensidade, busca possibilitar um recurso alternativo ao antiveneno. Camundongos Swiss (Mus musculus) machos, adultos jovens (6-8 semanas), massa corporal média de 22-25 ± 3g, receberam injeção intramuscular (m. gastrocnêmio direito) (20-25?l) do veneno liofilizado (diluído em NaCl 0,9%) de serpente do gênero Bothrops jararacussu (Bjssu) na concentração de 0,83mg/kg [grupos "veneno" (V), "veneno + laser" (VL) e "veneno + laser desligado"(VLP)]. Paralelamente, foi administrada injeção de NaCl 0,9% em animais dos grupos "salina" ["salina" (S), "salina + laser" (SL) e "salina + laser desligado" (SLP)]. A primeira irradiação laser (GaAs-904nm; área de tratamento: 1,0cm²; densidade de potência: 20 W/cm²; densidade de energia: 4 J/cm²; 4J/sessão de tratamento; modo contínuo; ponto único em contato direto; 1min 32s) foi realizada 3h pós-lesão/injeção de Bjssu/NaCl 0,9%, respectivamente nos grupos VL e SL. O tratamento foi repetido após 24, 48 e 72h. Desde o momento pré-lesão, os animais passaram por análise da função motora dinâmica por meio do sistema CatWalk. Terminado o período de 72h, foram sacrificados em câmara de CO2 e o m. gastrocnêmio coletado para análise. As amostras foram processadas e submetidas a técnicas de análise histológica, PCR quantitativa, espectroscopia Raman e FT-IR. Os animais dos grupos V e VLP não realizaram apoio do membro posterior direito (mantiveram postura flexora reflexa) no período de 3h pós-lesão, diferentemente (p<0,05) dos grupos VL, S e SL. A função motora foi reestabelecida em 24h. Na análise histológica foi observada extensa presença de infiltrado inflamatório na região da injeção de Bjssu, principalmente no período de 48h, tanto para os grupos V quanto para os grupos VL. Nos grupos S e SL as características morfológicas do tecido muscular permaneceram similares ao músculo intacto. A área de lesão mionecrótica foi significativamente menor (p<0,05) nos grupos tratados. Foi observada expressão relativa do gene miogenina significativamente maior (p<0,05) no período de 72h, para o grupo VL quando comparado ao grupo V. Por meio das técnicas de espectroscopia Raman e FT-IR foi possível caracterizar o tecido muscular normal e mionecrótico, bem como a influência do laser GaAs nestes tecidos. De maneira geral, podemos considerar que o laser GaAs promoveu melhora da função motora dinâmica, reduziu a área de lesão mionecrótica e influenciou a expressão gênica no modelo de mionecrose induzida por veneno de Bothrops jararacussu / Abstract: Muscle tissue is primarily affected in accidents with Bothrops venom. The study of the use of light through the low-level laser therapy seeks to enable an alternative tool to antivenom. Males Swiss mice (6-8 weeks old), mean body mass of 22-25 ± 3g, received intramuscular injection (right gastrocnemius) (20-25?l) of lyophilized Bothrops jararacussu venom (Bjssu) at a concentration of 0.83mg/kg ["venom" (V), "venom + laser" (VL) and "venom + laser off" (VPL) groups]. Similarly, was administered 0.9% NaCl injection into "saline" groups ["saline" (S), "saline + laser" (SL) and "saline + laser off" (SLP)]. The first laser irradiation (GaAs-904nm; 1.0cm² area of treatment; 20 W/cm² power density; 4 J/cm² energy density; 4J/treatment session; continuous mode; single point; direct contact; 1min 32s) was performed 3h post-injury/injection in VL and SL groups. Laser treatment was repeated after 24, 48 and 72h. From the moment pre-injury, animals underwent for dynamic motor function analysis through the CatWalk system. After the 72h period, animals were sacrificed in a CO2 chamber and gastrocnemius muscle collected for analysis. Samples were processed and subjected to histological analysis techniques, quantitative PCR, Raman and FTIR spectroscopy. The animals in V and VPL groups did not perform support of the right hindlimb (kept flexed in a reflex posture) 3h post-injury, unlike (p<0.05) VL, S and SL groups. Motor function was reestablished in 24h. Extensive inflammatory infiltrate in the Bjssu injection region was observed, mainly in the 48h period for both V and VL groups. Morphological characteristics of muscle tissue in S and SL groups remained similar to the muscle intact. The myonecrosis area was significantly lower (p <0.05) in treated groups. Relative expression of myogenin gene was significantly higher (p <0.05) at 72h period to VL group when compared to V group. Raman and FTIR spectroscopy techniques allowed the characterization of normal and injured muscle tissue as well the influence of GaAs laser on these tissues. In general we can consider that the GaAs laser improved the dynamic motor function, reduced the injury area and influenced gene expression in myonecrosis induced by Bothrops jararacussu venom / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

An optical study of Mn and Mo isotopes has been performed in two contrasting regions of the nuclear chart. Collinear laser spectroscopic methods were employed using the Ion Guide Separator On-Line (IGISOL) at the University of Jyväskylä, Finland. Optical pumping in an ion-trap with the use of frequency quadrupled titanium sapphire lasers, greatly improved the efficiency of the spectroscopy performed.For the first time, the change in mean-square charge radius was determined for ground and isomeric states in 50-56Mn with a sharp shell closure seen across N = 28. Nuclear quadrupole moments in 50m,53,54,56Mn were also extracted, displaying trends similar to those of the charge radii. Newly extracted hyperfine structures and isotope shifts of 90-92,94-98,100,102-106,108Mo span the N = 50 shell closure and well-known N = 60 shape change. Unlike the Z = 38 - 41 isotopic chains, Mo exhibits a smooth increase in mean-square charge radius, with no sudden onset of deformation at N = 60. These measurements signify the end point of this strongly deformed A ~ 100 region in both Z and N. In the Z ~ 40 region, the charge radii follow the trends in the mass measurements near perfectly. However, in the Mn measurements a clear disparity between the mass and charge radii measurements is seen across the N = 28 magic shell closure. The absence of any shell effects in the Mn mass measurements show the importance of charge radii measurements, with pertinent implications for future investigations in the N = 40 region. Additionally, a portable data acquisition system for laser spectroscopy has been successfully tested. It is based on the LabJack system which will directly interface to a USB connection. It is able to register individual photons from amplified and converted photomultiplier tube signals (with bunched or continuous ion beams). The device drives a Cooknell voltage supply, which steps the voltage across the laser-ion interaction region. The introduction of an accurate 100 ms time window into the LabJack system has enabled a precise photon detection system for future off-line testing and on-line use. Further to this, a new method of locating hyperfine resonances has been introduced into our spectroscopy.

The neutron-deficient gallium isotopes down to N=32 have had their hyperfine structures and isotope shifts measured via collinear laser spectroscopy using the COLLAPS (COllinear LAser sPectroScopy) beam line. The ground-state spin of 63Ga has been determined as I = 3/2 and its magnetic dipole and electric quadrupole moments were measured to be µ = +1.469(5) µN and Qs = +0.212(14) b respectively. The nuclear moments of 70Ga were measured to be µ = +0.571(2) µN and Qs = +0.105(7) b. New isotope shift results were combined with previously measured values of the neutron-rich isotopes and the changes in mean-square charge radii of the entire gallium isotope chain were investigated. Analysis of the trend in the neutron-deficient charge radii demonstrated that there is no evidence of anomalous charge radii behaviour in gallium in the region of N=32. A sudden increase of the charge radii was observed at the N=50 shell gap and an inversion of the normal odd-even staggering effect was seen at N=40.The development of the CRIS (Collinear Resonant Ionisation Spectroscopy) beam line is reported, detailing the components that have been installed since its proposal in 2008. Results from the first experimental campaign on francium are discussed to present the current operational status of CRIS. Initial results demonstrate an experimental efficiency of 1:70, collisional background rate of 1:10^5 and a resolution of 1.5 GHz. Analysis of the 221Fr data provided an experimental accuracy of measurements using CRIS, with 44 MHz for the A(7s 2S1/2) hyperfine coefficients and 360 MHz for the isotope shifts. The A(7s 2S1/2) hyperfine coefficients and isotope shifts were measured for 207,211,220,221Fr and show good agreement with literature values. The isotope shifts were combined with literature values to determine the atomic factors for the 7s 2S1/2 to 8p 2P3/2 atomic transition so that changes in the mean-square charge radii could be extracted and compared with literature. The results demonstrate the successful commissioning of the CRIS experiment.

Epithelial ovarian cancer is the fifth leading cause of cancer-related deaths in the United States. However, the mortality rate is relatively high, due to in part to the cancer being in an advance stage at diagnosis, since it is often asymptomatic at the early-stage with a ~94% of five-year survival rate if it is diagnosed at a localized stage (stage 1). Early detection of cancer would likely improve the survival rate. Scientists are searching for novel promising methods to detect ovarian cancer at an asymptomatic early stage; also, the method is cheap and user-friendly despite there are various techniques for ovarian cancer detection. Cancer antigen 125 (CA125), a type of serum biomarker that elevates ~50% of women with early-stage and ~80% of women with advanced-stage, is used mostly for screening epithelial ovarian cancer. However, the lack of sensitivity and specificity are known to be the main drawback of CA125. Finding new potential biomarkers that diagnose cancer at a localized stage will significantly reduce the mortality rate. Human epididymis protein 4 (HE4) is such a biomarker that has a higher sensitivity and specificity compared to all other known biomarkers, and recently it has been approved by food and drug administration (FDA) for clinical applications.In this project, we developed sandwich-type micro particles immunoassay for sensitive detection of HE4 biomarker in plasma. Here, we cross-link elemental particles to a specific functional group of the targeted biomolecules based on a covalent and non-covalent linking chemistry to improve the sensitivity and the selectivity of biomarker detection in which Fe3O4 and SiO2 microparticles were used to conjugate and purify the antibody-antigen in a media. The purified assay with the microparticles was analyzed with laser-induced breakdown spectroscopy (LIBS) for detection and quantization analysis of the HE4 biomarker. Furthermore, along with LIBS, Raman, Fourier transform infrared (FT-IR), and UV- Vis spectroscopic techniques were utilized to understand the conjugation dynamic and confirm the conjugation process.

Metal halide perovskites have emerged as photoactive materials in solution-processed devices thanks to their unique properties such as high absorption coefficient, sharp absorption edge, long carrier diffusion lengths, and tunable bandgap, together with ease of fabrication. The single-junction perovskite solar cells have reached power conversion efficiencies of more than 25%. Although the efficiency of perovskite devices has increased tremendously in a very short time, the efficiency is still limited by carrier recombination at defects and interfaces. Thus, understanding these losses and how to reduce them is the way forward towards the Shockley-Queisser limit. This thesis aims to apply ultrafast optical spectroscopy techniques to investigate the recombination pathways in halide perovskites, and understand the charge extraction from perovskite to transport layers and nonradiative losses at the interface. The first part focuses on perovskite solar cells with planar n–i–p device architecture which offers significant advantages in terms of large scale processing, the potential use of flexible substrates, and applicability to tandems. In addition to the optimization of MAPbI3 solar cell fabrication using a modified sequential interdiffusion protocol, the photophysics of perovskites exposed to humid air and illumination are discussed. The MAPbI3 film processed with the addition of glycol ethers to the methylammonium iodide solution results in the control of PbI2 to perovskite conversion dynamics, thus enhanced morphology and crystallinity. For samples exposed to humid air and illumination, the formation of sub-bandgap states and increased trap-assisted recombination are observed, using highly-sensitive absorption and time-resolved photoluminescence measurements, respectively. It appears that such exposure primarily affects the perovskite surface. The second part discusses the hole extraction from Cs0.07Rb0.03FA0.765MA0.135PbI2.55Br0.45 to the polymeric hole transport layer and interfacial recombination using ultrafast transient absorption spectroscopy technique. To illustrate this, PDPP-3T was used as HTL, since its ground state absorption is red-shifted compared to the perovskite’s photobleach, thereby allowing direct probing of the interfacial hole extraction and recombination. Moreover, carrier diffusion is investigated by varying the perovskite film thickness, and carrier mobility is found to be 39 cm2V-1s-1. Finally, hole extraction is found to be one order of magnitude faster than the recombination at the interface.

Title: Time-resolved spectroscopy of SiV centers in diamond Author: Karol Hamráček Department: Department of chemical physics and optics Supervisor: doc. RNDr. František Trojánek, Ph.D. Abstract: In recent years, the negatively charged silicon center (SiV-) has become a promising competitor to well-established nitrogen (NV-) due to its excellent spectral properties, such as narrow zero phonon line transitions and weak phonon sidebands, and therefore, research of point defects in diamond is currently receiving a lot of attention. These isolated defects, the so- called color centers, can serve as sources of photons and thus, ultimately, can be used to construct SiV Lasers, whose physical nature is stimulated emission. However, it has not yet been generated at SiV centers. For its generation, it is necessary to examine in detail the radiant and non-radiative processes in optical centers and the properties and parameters of stimulated emission during optical excitation. Also part of the research is the optimization of sample preparation in order to obtain samples with a high concentration of centers and at the same time high optical quality. That is why the aim of this diploma thesis will be to perform optical characterization of diamond samples with SiV centers (supplied by the cooperating department of the...

Direct, efficient oxidation of alkanes is a long-standing goal of catalysis. Gas phase FeO+ can convert methane to methanol and benzene to phenol under thermal conditions. Two key intermediates of these reactions are the [HO-Fe-R]+ insertion intermediate and Fe+(ROH) (R=CH3 or C6H5) exit channel complex. This work describes measurements of the vibrational spectra of these intermediates and electronic structure theory calculations of the potential energy surfaces for the reactions. They help to characterize the mechanism for these reactions. Chapter 1 describes previous studies of methane-to-methanol and benzene-to-phenol conversion by gas-phase transition metal oxide cations. Spectra of gas-phase reaction intermediates are obtained using photofragment spectroscopy, in which absorption of a photon leads to bond breaking. Utuilizing this technique to measure vibrational spectra is challenging, due to the low photon energies involved. Techniques used to measure vibrational spectra of ions - argon tagging, infrared multiple photon dissociation (IRMPD), vibrationally mediated photodissociation (VMP) and infrared laser assisted photodissociation spectroscopy (IRLAPS) are also detailed in chapter 1. The photofragment spectrometer and laser systems used in these studies are described in chapter 2, as is a multi-pass mirror arrangement which I implemented. This greatly improved the quality of vibrational spectra, particularly those measured using IRMPD. Chapter 3 describes studies of the O-H and C-H stretching vibrations of two intermediates of the FeO+ + CH4 reaction. These intermediates are selectively formed by reaction of laser ablated Fe+ with specific organic precursors and are cooled in a supersonic expansion. Vibrations of the sextet and quartet states of the [HO-Fe-CH3]+ insertion intermediate and Fe+(CH3OH) exit channel complex are measured by IRMPD and Ar-tagging. Studies of the O-H stretching vibrations of the [HO-Fe-C6H5] + and Fe+(C6H5OH) intermediates of the FeO+ + C6H6 reaction are discussed in chapter 4. For Fe+(C6H5OH), the O-H stretch is observed at 3598 cm-1. Photodissociation primarily produces Fe+ + C6H5OH. IRMPD of [HO-Fe-C6H5] + mainly produces FeOH+ + C6H5 and the O-H stretch spectrum consists of a peak at ~3700 cm-1 with a shoulder at ~3670 cm-1. Chapter 5 compares three techniques - IRMPD, argon-tagging, and IRLAPS - in the quality of the measured vibrational spectra of Ag+(CH3OH) ions produced under identical conditions. The sharpest spectrum is obtained using IRLAPS. The O-H stretch is observed at 3660 cm-1. Monitoring loss of argon from Ag+(CH3OH)(Ar) gives a slightly broader peak, with no significant shift. The vibrational spectrum obtained using IRMPD is shifted to 3635 cm-1, is substantially broader, and is asymmetrical, tailing to the red.

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