Theoretical And Experimental Studies In Visible Laser Spectroscopy

In this thesis, two different aspects of the interaction of radiation with molecules are studied. First, a previously-derived exact solution to the time-dependent Schroedinger equation describing the interaction between a sinusoidally-oscillating field and an N-level atomic or molecular system is used to examine the temporal and steady-state behaviour of a five-level model molecular system. Secondly, the technique of polarization labelling spectroscopy is used to study the E 0(,g)(\u27+) state of the iodine molecule.;The behaviour of the five-level system, consisting of a ground state and four nearly degenerate excited states, is studied for various experimental conditions, and for single- and three-photon transitions. From these calculations, it is possible to predict some aspects of the behaviour of molecules in laser radiation fields of varying intensities. When the laser intensity is strong, the excited states behave like a single band. When the laser intensity is weak, an interpretation in terms of individual two-level systems is possible. The multi-photon results show that an underlying interaction between levels persists even when the spectrum appears to consist of well-separated peaks.;The introduction of differing individual relaxation terms for the energy levels is discussed, and it is shown that the previous formalism for the undamped temporal results, with some modifications, can be used to describe the damped systems. A uniform damping model is used to demonstrate how peaks in a steady-state spectrum corresponding to transitions with differing temporal behaviour can be differently damped. Generally, the temporal behaviour of the undamped system is useful for predicting the results in the damped examples.;In polarization labelling spectroscopy, only probe laser radiation corresponding to labelled transitions is recorded, so the technique is very useful in simplifying otherwise complicated molecular spectra. In this work, the technique has been used in a two-photon excitation experiment to study the E state of the iodine molecule. Although iodine has been studied extensively, the ion-pair states are only now being well-characterized. The results of the polarization labelling experiments presented here are used to obtain better determinations of the molecular constants describing the E state

Features of seismic waves recorded by seismic exploration in 2002: Responses from valley structure of the bedrock beneath Mizuho Plateau

Seismic waves from natural sources were recorded in seismic exploration experiments in January 2002 by the 43rd Japanese Antarctic Research Expedition (JARE-43). Three kinds of seismic waves were recorded: (1) a teleseismic event occurred in the Kermadec Is. region, (2) local icequakes and (3) an unidentified event. The teleseismic waves show high signal-to-noise ratio in spite of the small magnitude of the event: this indicates that it is highly feasible to study not only the local shallow structure but also the deep structure of the earth by using teleseismic events. Frequency spectra of the waveforms show discordances along the observation line. The 2.0 Hz frequency component is very small in waveforms recorded by stations in the middle part of the observation line. On the other hand, the 1.5, 3.0 and 5.0 Hz frequency components are large in the records of these stations. These stations are located just above the valley topography of the interface between the ice sheet and the upper crust, which has been revealed by JARE-41 and JARE-43 seismological experiments

Edge-dominating cycles in graphs

AbstractA set S of vertices in a graph G is said to be an edge-dominating set if every edge in G is incident with a vertex in S. A cycle in G is said to be a dominating cycle if its vertex set is an edge-dominating set. Nash-Williams [Edge-disjoint hamiltonian circuits in graphs with vertices of large valency, Studies in Pure Mathematics, Academic Press, London, 1971, pp. 157–183] has proved that every longest cycle in a 2-connected graph of order n and minimum degree at least 13(n+2) is a dominating cycle. In this paper, we prove that for a prescribed positive integer k, under the same minimum degree condition, if n is sufficiently large and if we take k disjoint cycles so that they contain as many vertices as possible, then these cycles form an edge-dominating set. Nash-Williams’ Theorem corresponds to the case of k=1 of this result

Meiotic gene silencing complex MTREC/NURS recruits the nuclear exosome to YTH-RNA-binding protein Mmi1.

Accurate target recognition in transcript degradation is crucial for regulation of gene expression. In the fission yeast Schizosaccharomyces pombe, a number of meiotic transcripts are recognized by a YTH-family RNA-binding protein, Mmi1, and selectively degraded by the nuclear exosome during mitotic growth. Mmi1 forms nuclear foci in mitotically growing cells, and the nuclear exosome colocalizes to such foci. However, it remains elusive how Mmi1 and the nuclear exosome are connected. Here, we show that a complex called MTREC (Mtl1-Red1 core) or NURS (nuclear RNA silencing) that consists of a zinc-finger protein, Red1, and an RNA helicase, Mtl1, is required for the recruitment of the nuclear exosome to Mmi1 foci. Physical interaction between Mmi1 and the nuclear exosome depends on Red1. Furthermore, a chimeric protein involving Mmi1 and Rrp6, which is a nuclear-specific component of the exosome, suppresses the ectopic expression phenotype of meiotic transcripts in red1Δ cells and mtl1 mutant cells. These data indicate that the primary function of MTREC/NURS in meiotic transcript elimination is to link Mmi1 to the nuclear exosome physically

Preparation of Some α-Substituted Cyclopropanecarboxylic Acids via Dichlorocarbene

Some α, β-unsaturated esters (1), including trans-crotonate, trans-α-methoxycrotonate, irans-α-fluorocrotonate, trans-cinnamate, trans-α-chlorocinnamate, cis- and trans-α-fluorocinnamates, fumarate, and maleate, were allowed to react with dichlorocarbene, generated by the thermal decomposition of sodium trichloroacetate at 120-160°C, to give the corresponding β, β-dichlorocyclopropanecarboxylates (2) in fair to good yields (38-88%). The additions of dichlorocarbene to these esters were stereospecific. A similar reaction of n-butyl acrylate gave only a very low yield (6%) of the dichlorocarbene adduct, probably because of the accompanying polymerization of the starting ester. The reduction of 1-unsubstituted or 1-methoxysubstituted 2, 2-dichloro-3-methylcyclopropanecarboxylate with tri-n-butyltin hydride at 90°C yielded both the completely reduced (3) and the partially reduced esters (4 and 5). That of 1-fluoro-substituted ester gave only the completely reduced product. These cyclopropanecarboxylates (2 and 3) were hydrolyzed with potassium hydroxide to give the corresponding free acids (6 and 7) in good yields (72-92%). The properties (bp, mp, nᴅ, pmr spectral data, etc.) of the cyclopropanecarboxylic acids and esters thus prepared are described

The physiological response during optogenetic-based cardiac pacing in awake freely moving mice

There are several methods to control a heart rate, such as electrical stimulation and drug administration. However, these methods may be invasive or affect other organs. Recently, an optogenetic-based cardiac pacing method has enabled us to stimulate the cardiac muscle in non-contact. In many previous studies, the pacing was applied ex vivo or in anesthetized animals. Therefore, the physiologic response of animals during optogenetic pacing remains unclear. Here, we established a method of optogenetic-based cardiac pacing in awake, freely moving mice and simultaneously measured electrocardiogram, blood pressure, and respiration. As a result, light-induced myocardial contraction produces blood flow and indirectly affects the respiration rhythm. Additionally, light illumination enabled heart rate recovery in bradycardic mice. These findings may be employed for further research that relates a heartbeat state to animal behavior. Together, this method may drive the development of less invasive pacemakers without pacing leads