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Eukaryotic cell growth, maintenance and differentiation relies on the dynamic structure of nuclear chromatin, the macromolecular complex consisting primarily of DNA and histones. Changes to chromatin structure and chemistry may lead to alterations in gene expression, resulting in functional and developmental processes in cells. Additionally, biomechanical properties of the nucleus, which play a role in mechanical signalling pathways, are also affected by chromatin conformation. The regulation and effects of chromatin dynamics in cellular processes have yet to be fully elucidated. Therefore, novel techniques for assessing chemical and mechanical signatures of cells undergoing chromatin changes during cell differentiation at the single cell level have great potential for 1) phenotypic characterisation of single cells for research and clinical purposes and 2) further unravelling the complex coordination of intracellular changes that occur during cell developmental steps and triggering of disease. In this thesis, I have studied chromatin remodelling in immune cells using vibrational spectroscopy and microfluidics. Single cell measurements were conducted through optimisations of experimental and data analysis parameters. Vibrational spectroscopy methods included FTIR spectroscopic imaging and Raman microscopy, both label-free techniques that measure the interaction of light with chemical properties of a sample by interrogating its molecular vibrations. Microfluidics is a technique for manipulating fluids at a submillimetre scale. It was utilised here to enable live cell Raman mapping, as well as for deformability cytometry for assessing mechanical properties of the cell nuclei. To initiate an immune activation, B cells were incubated with a cytokine (CIT) cocktail. The biomechanical property, nuclear auxeticity, was investigated in B cells using deformability cytometry. This property has previously been shown in transitioning embryonic stem (ES) cells, and chromatin decondensation has been determined to hold a regulatory role. Chromatin decondensation was therefore induced in B cells through immune activation (CIT treatment) or Trichostatin A (TSA) treatment. These cells were compared to untreated control cells. A subset of cells for both the CIT and TSA treatment, had auxetic nuclei. No control cells had auxetic nuclei. These results showed nuclear auxeticity in B cells for the first time, and linked it to chromatin decondensation in agreement with previous ES cell data. Using FTIR spectroscopic imaging and Raman microscopy, spectral features associated with chromatin and DNA changes during immune B cell activation were identified. Peak ratios for distinguishing between non-activated and activated immune cells were determined - for FTIR imaging: a DNA-to-protein peak ratio, and for Raman mapping: a peak ratio between two neighbouring peaks, both associated with nucleic acid. Both peak ratios measured the relative change in a peak associated with νs(PO2-), which was therefore shown to be a potential spectral marker for label-free characterisation of immune cells pre- and post activation. The biological origin of the FTIR spectral features was further investigated using additional cell treatments. Chromatin decondensation, intiated through CIT or TSA treatment, gave rise to similar change in the DNA-to-protein peak ratio. This supported the hypothesis that the νs(PO2-) spectral changes can be used to monitor structural changes occurring in chromatin and DNA itself. Finally, the key biological pathways influencing the whole range of Raman spectral differences between non-activated and activated B cells were investigated. Partial least squares (PLS) regression was performed on Raman maps and transcriptomic data. It was determined that a linear correlation exists between the two data types. Transcripts of high importance for this correlation were identified. These included the B cell receptor genes and a number of transcripts of regulatory proteins with known roles in immune activation. Transcripts not previously linked to immune activation were also identified. In summary, novel techniques for phenotypic characterisation of single cells were explored using both chemical and mechanical measurements of B cells undergoing immune activation. Previously unidentified biochemical and biomechanical factors influencing B cell activation were identified. These have added new layers to our understanding of this process and thus revealed potential new research directions. Furthermore, chromatin decondensation and transcriptional changes are key responses during all cell differentiation processes and disease development. Therefore, these experimental approaches have great potential for investigating other cell types and cellular processes.

Nanomedicine includes detection, diagnosis and treatment of diseases at the cellular level and can be a valuable tool for highly specific medical interventions by utilising nanoscale objects. Cancer nanomedicine is one of the most successful research fields for exploring cancer at the cellular level. To find a suitable candidate for cancer theranostics (therapy and diagnosis) at an early stage and post-treatment (reemission), the cytotoxicity, imaging, and therapeutic capabilities of various classes of nanoparticles were investigated. Firstly, various nanoparticles were first obtained from WOx and iron oxides being processed under hydrogen (H2) + argon (Ar) gas heat treatment and membrane filtration. A colouration process from yellow to blue colour was obtained for WO3 nanoparticles (NPs) and an oxygen reduction process that led us to obtain metallic Fe NPs from γ-Fe2O3 NPs. Additionally, membrane filtration methods using ultrathin nanoporous membranes in microfluidic platforms were performed on γ-Fe2O3 polydisperse NPs. This novel application showed a consistent reduction in size distribution from these magnetic polydisperse NPs after filtration at 37 nm and 60 nm membrane pore sizes. Tangential and normal flow filtration (TFF and NFF, respectively) were used with ethanol and water solvents which showed the need to work at low concentrations for dense nanoparticles. TFF presented a higher degree of filtration at the cost of complexity, time and price. Secondly, these NPs were then investigated for their incorporation as the core in core-shell structures. Novel core-shell NP structures were designed with an intermediate tunable SiO2 layer (3-60 nm) using the Stober process and also a tunable Au outer shell (15-30 nm approximately) formed from 3.5 nm Au seeds obtained from the Turkevich method. WO3-SiO2-Au NPs were synthesised which are a new class of NP that contains a first in it class WO3 core with potential electrochromic functionalities. Coherent anti-Stokes Raman spectroscopy (CARS) and near-infrared (NIR) surface-enhanced Raman spectroscopy (SERS ) were performed as a proof of concept for potential medical imaging to locate the nanoparticles achieving single-cell resolution. SERS enhancement factor (EF) using 785 nm was approximately 103 for a 30 nm thick Au shell in a silicon wafer. Additional Raman signals were measured in liquid samples to evaluate obtaining a SERS EF of 771 with WOx core and 33 using γ-Fe2O3 core. It presented low toxicity at concentrations under 100 μg/mL after 24 h using human isolated at M D Anderson from a pleural effusion of a patient with invasive ductal breast carcinoma breast cancer cells (MDA-MB 231) in vitro. Finally, monodisperse γ-Fe2O3-SiO2-Au nanoparticles displayed a promising negative contrast for MRI in both T1 and T2 modes along with strong contrast under microcomputed tomography (μCT). Monodisperse γ-Fe2O3 cores, which have an average diameter of 11 nm following a gaussian distribution with a standard deviation of 3 nm, in γ-Fe2O3-SiO2-Au structures outperformed in all these imaging tests to polydisperse γ-Fe2O3 cores, which have a mode value at 31 nm following a Lorentzian distribution with a scale parameter of 29 ± 7 nm. Magnetic hyperthermia was achieved using γ-Fe2O3 cores confirmed the potential therapy functionality in water using AMFs at 515 kHz and 170 Oe, obtaining an increment of 7 °C in 23 min, which adds in total four functionalities with potential application for cancer nanotheranostics. Moreover, cell viability assays using monodisperse γ-Fe2O3-SiO2-Au nanoparticles showed almost negligible cytotoxicity in different nanoparticle concentrations (0-2000 μg/mL) and cell types (pericytes, embryonic kidney HEK293A and MCF10A human cells) in vitro. In conclusion, the thesis was able to demonstrate that WO3-SiO2-Au NP and γ-Fe2O3-SiO2-Au NP have the potential for further development as a tool in nanomedicine, although systemic toxicology and excretion pathways will have to be carefully studied next.

Breast cancer is the second most common cause of death from cancer in women, accounting for more than 1 million deaths globally per year. Current detection is based on X-ray mammographic screening, which involves the use of ionising radiation with potentially detrimental effects, or MRI scans, which have limited spatial resolution. The presence of microcalcifications in breast tissue has been associated with malignant disease. Unfortunately, X-ray mammography and MRI scanning techniques are not able to discriminate between microcalcifications from a benign lesion and those from a malignant lesion. The aim of this project was to use optical techniques based on vibrational spectroscopy, such as Fourier Transform Infrared (FTIR) absorption and Raman scattering, which are non-destructive, label-free and chemically specific, to investigate the composition of microcalcifications in breast tissue for augmented diagnostics and improved outcome for the patient. This work involved the characterisation of mineral standards of the type that can be found in the breast, in order to identify the precise composition of the microcalcifications. A series of calcium hydroxyapatite (Hap) compounds was used for calibration of the micro-FTIR and Raman spectra. The ratio of carbonate-to-phosphate band intensity for each individual Hap powder was determined and the data were used to assess the level of carbonate substitution in each breast tissue biopsy. In parallel, the analysis of potential precursor mineral phases (namely octacalcium phosphate and amorphous calcium phosphate) revealed similar features to Hap in both FTIR and Raman spectra, which can be translated to the biopsy samples. The accessibility to diverse panels of breast tissue sections (frozen and paraffin-embedded) was a great opportunity to test different approaches. A deparaffinisation protocol was applied to a set of samples for Raman analysis and the process was found not to affect the microcalcification composition. The FTIR analysis of the frozen tissues provided information on the carbonate peak in the short wavelength range (1500-1400 cm-1), which normally contains a strong contribution from paraffin in standard histological specimens. The study of breast tissue sections showed the heterogeneity in composition of microcalcifications between different samples from the same stage of pathology in terms of protein, lipid - which is usually not observed in formalin-fixed paraffin-preserved (FFPE) sections - and carbonate content. The mineralisation of the MDA-MB-231 breast cell line induced by two osteogenic agents: inorganic phosphate (Pi) and b-Glycerophosphate (bG) was investigated using Raman micro-spectroscopy. The uptake of osteogenic agent induced a faster mineralisation for cells cultured with a medium supplemented in Pi (day 3) than bG (day 11). A shift (± 3 cm-1) of the phosphate peak at 956 cm-1 in the Raman spectra was apparent when the culture medium was supplemented with bG, indicating the presence of precursor phase (octacalcium phosphate) during Hap crystal formation. New IR technologies such as bright laser sources e.g. quantum cascade laser (QCL) open possibilities for the analysis of biological samples. They allowed us to achieve a better signal-to-noise ratio than Globar thermal sources used in traditional FTIR systems, particularly on optically dense samples such as calcifications. The ability of selecting specific incident wavelengths allows significant improvements in the acquisition time. This work illustrates for the first time the identification of microcalcifications using a QCL source in the long wavelength range coupled to an upconversion system with a silicon detector for efficient sensing. The upconverted images showed a good agreement with the micro-FTIR images. Vibrational spectroscopy has been shown to be a powerful tool for discrimination of mineral species in breast calcification. These techniques can provide complementary information for the pathologist to be able to classify breast pathologies - benign, ductal carcinoma in situ (DCIS) and invasive cancer - with higher accuracy.

Vibrational spectroscopic diagnostic techniques have significant potential to improve the care of women with benign, premalignant and malignant vulval diseases by reducing the reliance on traditional biopsy and histopathology. These techniques also have the potential to augment clinicians’ ability to differentiate different types of vulval disease at the time of surgery for neoplastic vulval disease. In addition, vibrational spectroscopic techniques offer the opportunity to assess molecular changes associated with the development of vulval cancer that are not apparent on routine histopathological assessment. The work outlined in this thesis evaluates the role of emerging techniques in vibrational spectroscopy to address this need within three key themes: 1. Developmentofavibrationalspectroscopicdiagnostictechniquetoreducethe reliance on traditional biopsy and histopathological diagnosis. 2. Developmentofavibrationalspectroscopicdiagnostictechniqueforimproving the delineation of disease margins at the time of surgery for pre-malignant and malignant vulval conditions. 3. Evaluation of a vibrational spectroscopic tool for augmenting and automating aspects of vulval histopathology. Raman spectroscopic mapping of 91 fresh frozen vulval tissue sections combined with multivariate spectral analysis was used to demonstrate that malignant vulval disease could be differentiated from non-neoplastic and premalignant vulval disease with a sensitivity of 97% and specificity of 78%. The technique was then tested in experimental conditions closer to in-vivo application, measuring spectra from 91 whole fresh frozen tissue blocks using microscope and probe Raman systems. This demonstrated the technique could differentiate malignant from non-neoplastic and premalignant vulval disease with sensitivities of 84% to 92% and specificities of 84% to 64% respectively. In a separate investigation vulval tissue blocks from 27 women with suspected lichen sclerosus underwent Raman spectroscopic point measurements. Multivariate analysis demonstrated Raman spectroscopy could be used to differentiate lichen sclerosus from other vulval disorders with a similar clinical appearance with a sensitivity of sensitivity of 91% and specificity of 80%. Fourier transform infrared (FTIR) spectroscopic mapping of 93 fixed paraffin embedded tissue sections was used to demonstrate that malignant vulval disease could be differentiated from non-neoplastic and premalignant with vulval disease with an approximate sensitivity of 100% and specificity of 79%. In addition FTIR spectroscopy was used to differentiate molecular changes in vulval intraepithelial neoplasia (VIN) and lichen sclerosus (LS) found in association with vulval squamous cell carcinoma (SCC). Analysis of FTIR spectroscopic tissue maps from 48 patients demonstrated the technique could differentiate LS associated with SCC with a sensitivity of approximately 100% and specificity of 84% and VIN associated with SCC with a sensitivity of approximately 100% and specificity 58%. This thesis demonstrates the considerable potential of vibrational spectroscopy in this clinical setting. The research has made significant progress in each of the three themes outlined above and indicates that further work is warranted to develop the techniques towards routine clinical application.

This thesis is written as part of Marie-Curie international training network called Mid-TECH. Mid-TECH is devoted to improve mid-infrared (MIR) technologies and consists of 15 PhD projects across European universities. This thesis aims to evaluate new technologies and concepts developed by the project partners for their applicability in a biomedical setting. The clinical problem to diagnose oesophageal cancers serves as an example case for this. The thesis consists of three projects all aimed to further the understanding of MIR hyperspectral imaging. The first project discussed in chapter 5 demonstrates the use of an new design of the United States Airforce resolution test chart. The new test chart is developed to evaluate spatial resolution of MIR hyperspectral imaging systems. The use of different materials is discussed and the new iteration of the thes chart is evaluated using a state of the art MIR imaging system. The second project discussed in chapter 6 evaluates the technical differences and their practical implications of discrete frequency MIR imaging systems compared to continuum source systems. A comparison of the two system types is drawn for imaging paraffin embedded sections of oesophageal tissue. Furthermore the effect of chemically removing the paraffin from the sample is compared to a mathematical correction algorithm. The system performance is compared based on their ability to differentiate healthy from cancerous tissue. The third project discussed in chapter 7 evaluates the potential of a new MIR detection scheme called upconversion in combination with a novel MIR laser source. It is a prove of concept study demonstrating that those two technologies can be deployed to do hyperspectral imaging in the MIR.

Oesophageal cancer, one of the most aggressive cancer types is considered the seventh most common cancer in terms of incidence and the sixth most common cause of cancer deaths worldwide due to late diagnosis. In the UK, the oesophageal cancer incidence rate has increased by approximately 10% since the 1990s. At present, histopathology is the gold standard method for the diagnosis of oesophageal cancer, which rely on biopsy collection using an endoscopy procedure followed by the histological sample's preparation. This method is invasive, time-consuming, and largely based on the pathologist's experience of diagnosis. Therefore, new diagnostic techniques are required to provide non-invasive methods for early and rapid diagnosis. Raman scattering has the potential to replace histopathology as the gold standard for diagnosis for a wide range of diseases. Raman scattering provides stain-free imaging with chemical-specificity derived from the intrinsic vibrational signatures of biomolecules. However, the low scattering cross-section severely limits the image acquisition speeds and like conventional histopathology, requires tissue sectioning to provide morphological imaging below the surface of tissue biopsies. Stimulated Raman scattering (SRS) has recently appeared as a powerful technique for (near)real-time Raman imaging in intact tissue samples. Thework in this thesis aimed to develop the stimulated Raman scattering (SRS) for rapid wavelength tuning and chemical imaging of clinical samples, such as cancer biopsies. This was achieved by making modification to a laser cavity to reduce the time of the wavelength tuning by approximately 35 times compared to the original cavity design. Furthermore, the cavity modification led to the spectra being separated efficiently and the wavelength tuning controlled by cavity length changes only. The improved design was applied to image frozen oesophageal tissues, which have four major pathology groups, normal, inflammation, columnar-lined (Barrett's) oesophagus (CLO) and low-grade dysplasia. A large area imaging was performed using the SRS technique at 2930 cm-1 for four different oesophageal tissues, which presented the morphological and structural information. However, histopathological diagnosis depends on the visualisation of the cell nucleus in the tissue. This component was not highlighted until the stimulated Raman histology approach was developed for small regions of interest in the CLO and the low-grade dysplasia sample, which required two different frequencies at 2840 cm-1 and 2930 cm-1. All SRS images were compared to haematoxlin and eosin (H&E) stained sections. Further comparisons were made between SRS and Raman imaging techniques, with SRS offering faster acquisition times and a higher spatial resolution. The spectral signature for the different pathological groups in the oesophageal tissues were explored in the high wavenumber (2800 - 2930 cm-1) region using hyperspectral SRS and compared with the spectra from the Raman. K-means clustering analysis was used to explore the morphochemical information using the CLO and low-grade dysplasia sections. Both techniques were able to demonstrate unique information such as the epithelial cells that form the oesophagus glands and surrounding connective tissue. It is concluded that SRS has the power to be one of the ideal imaging modalities to gather the molecular information in biological samples. However, it still needs more development due to the complexity of the system.

Low Temperature Nuclear Orientation (LTNO) is an important technique in the study of nuclei far from stability. The theory of LTNO and its application to the measurement of static nuclear moments and other quantities of spectroscopic interest are reviewed. The off-line facility at Oxford was used to study the decay of 133I→133Xe and 135I→135Xe. 133I having Z=53 and N=80 has three protons above the closed shell Z=50 and two neutrons holes in N=82 shell, while 135I has fully closed neutron shell since it has N=82, and they are of considerable theoretical interest since a wide variety of the theoretical nuclear models may be used to describe the observed levels close to the stable double closed shell structure. Another aim is to search for the nuclear magnetic dipole moment of the ground state of 135I. Nuclear orientation of 133IFe and 135IFe enabled the mixing ratios of several transitions in the decay scheme of 133I and 135I to be determined. From temperature dependence for 135I, the nuclear magnetic moment of 135I has been deduced. Also temperature dependence for 133I, analysed using a simple model, gave value for the magnetic hyperfine field that differed from previous published values. The method of combining nuclear orientation with NMR has become a very popular technique in recent years for determining nuclear magnetic dipole moments very precisely. The purpose of the NMR/ON experiment was to measure the hyperfine field with greater precision and to get some idea of the proportion of nuclei subject to it. Light Eu and Sm nuclei have attracted attention as systems with the number of protons right below the Z=64 subshell gap and the number of neutrons approaching N=82 major shell closure. Odd-proton, odd-neutron and odd-odd nuclei near the A=140 region have been investigated in the framework of the particle-triaxial rotor model. Main attention has been paid to explanation of experimental magnetic dipole and electric quadrupole moments of ground and isomeric states. Model predictions for deformation parameters of 136-142Sm even-even cores have been extracted.

Low Temperature Nuclear Orientation (LTNO) is an important technique in the study of nuclei far from stability. The theory of LTNO and its applications to the measurement of static nuclear moments and other quantities of spectroscopic interest are reviewed. Among the nuclei off the line of stability those in the A ~ 75 region are of considerable interest, exhibiting large quadrupole deformations, triaxiality and shape coexistence. LTNO measurements performed on neutron deficient bromine isotopes have yielded the static magnetic dipole moments of the nuclei ^{72g,72m,74m,75,76,77Br, Spectroscopic information on 72-77Se and also identified the ground state spin of 73Br as l/2‾ Existing odd A and odd-odd particle-rotor computer codes have been extended in order to include a Variable Moment of Inertia (VMI) asymmetric rotational core. The formalism necessary for this modification is developed. The measured magnetic moments are interpreted within the framework of this particle - VMI rotor model. It is shown that the systematic reduction in the moments of the odd A nuclei 75-81Br characterizes the transformation of the prolate ground state configuration from largely π[301]3/2 in 79,81Br to almost pure π[312]3/2 in 75,77Br. This trend is fully consistent with the increase in deformation towards the lower masses suggested by the known electric quadrupole moments. In contrast, the ground state spin of 73Br can only be interpreted in terms of an oblate nuclear shape. This is the first evidence for the predicted prolate-oblate shape transition in the bromine nuclei. In addition the magnetic moment of 74Brm, by identifying a π[431]3/2ν[422]5/2 configuration, strongly suggests a positive parity assignment for the isomeric state. Finally, an experiment to search for possible T-violation effects in nuclear gamma decay is described. Using coincidence techniques, a measurement of the T-odd P-even quantity (I ‧ k x e)(I ‧ k)(I ‧ e) has lead to a limit on the T-violating phase angle between the E2 and Ml matrix elements associated with the 604 keV gamma transition in 192Pt of sin η = ±11(12) x 10-3.}

On-line nuclear orientation at low temperature has become an important technique for the study of nuclei far from stability, through measurements of nuclear moments and other quantities of spectroscopic interest. The theory of low temperature nuclear orientation and its application to the study of nuclear structure are reviewed. Of particular importance to the on-line measurement, in which a wide range of short-lived nuclei are available for study, is the question of how fast these nuclei can be cooled to the lattice temperature, and thus oriented. To address this, the theory of nuclear spin-lattice relaxation, relevant to the online technique, is outlined. In particular, quantitative methods to deal with cases in which the spin-lattice relaxation time is comparable with the isotope half-life have been developed and applied. One of the major current interests in nuclear structure physics is to investigate how the neutron-proton interaction influences the structure of nuclei that are transitional, between well established regions of spherical and deformed nuclei. In such nuclei, intruder excitations, which signal the onset of deformation, are observed low in energy. Using the Daresbury on-line isotope separator, an extensive study of the decay of 118I to 118Te has been performed using nuclear orientation techniques, combined with γ - γ and conversion electron spectroscopy measurements. Interpretation of the results obtained for 118Te within the framework of IBM-2, gives strong evidence for the existence of such an ,em>intruder configuration in this nucleus. On-line experiments have also been performed in which a range of neutrondeficient Cs nuclei has been oriented for the first time. In these measurements the hyperfine field of CsFe has been determined as (+)40.8(7) T, and also the Korringa constant for the system 121CsmFe has been measured (using a new technique) to be Ck = 0.059(l6)sK. These results have been applied to the case of 118Csm, for which the magnetic moment has been measured to be 5.4(1.1)nm. This large value clearly indicates the presence of the [404]9/2 orbital, which provides further evidence for the existence of intruder states in this region.

Experiments are described in this thesis using the techniques of nuclear orientation and nuclear magnetic resonance to study the hyperfine interactions of dilute impurities in ferromagnetic metal hosts. The work is particularly concerned with the study of systems for which the more accurate measurement of the hyperfine interaction by the observation of nuclear magnetic resonance provides more information about the hyperfine interaction, and the nuclear parameters of the radioactive impurity, than can be obtained by a nuclear orientation experiment alone. The two aspects of this theme are combined in several experiments, where an accurate description of the decay transitions depends on the ability to provide a complete description of the orientation of the parent nucleus, from the resonance experiment. The experimental results can be considered in two parts. The use of the nuclear resonance technique to study the hyperfine interactions of dilute impurities, has concentrated on the observation and measurement of contributions to the hyperfine interaction from localised orbital magnetic moments on heavy impurities in the three cubic ferromagnetic lattices, iron, cobalt and nickel. The mechanism of the formation of localised magnetic moments at impurity atoms is discussed in chapter four. The cubic symmetry of the three host lattices will tend to quench the orbital angular momentum of a substitutional ion, but the strong spin-orbit interaction associated with heavy impurities will compete with the crystal field, and tend to produce a small orbital magnetic moment localised at the impurity site. Such an effect can be observed through the detection and measurement of either the magnetic orbital dipolar hyperfine interaction or an electric quadrupole interaction. The nuclear resonance technique is sensitive to both these interactions in the appropriate circumstances. The two impurities studied have provided an example of each measurement. Two isotopes of gold, dissolved as dilute impurities in iron, cobalt and nickel, have enabled the magnetic orbital dipolar hyperfine fields to be studied through the measurement of the hyperfine anomaly. The comparison of the measured value of the hyperfine anomaly in these hosts with the known value associated with a pure S-electron contact hyperfine field, allows the contribution to the hyperfine fields from a non-contact, orbital field, to be separated and measured. Since both a magnetic orbital dipolar field and an electric quadrupole interaction will arise from the unquenching of the orbital angular momentum, the effect of both contributions on the ratio of the observed nuclear resonance frequencies of 198Au and 199Au must be measured. The other systems studied have been dilute impurities of iridium in nickel and cobalt. The interaction of the host conduction electrons of a nickel lattice with an iridium impurity his been shown by Demangent and Gantier [64] to result in the formation of a localised magnetic moment on the impurity. This has been detected in the N.M.R/O.N. experiments by the finite electric quadrupole interaction resulting from the unquenching of the orbital angular momentum, through the spin-orbit interaction. The comparison with other measurements, and with the estimate of the orbital dipolar hyperfine field, from the Mossbaiier measurements of the hyperfine anomaly between the ground and first excited states of 193Ir, have suggested a magnitude for the orbital magnetic moment of +0.2andmu;B. The second aspect of this study has used the knowledge of the hyperfine interaction from a nuclear resonance experiment to analyse nuclear orientation measurements on two isotopes, 110Agm and 192Ir, in terms of the M1/E2 mixing ratios of several of the gamma-ray transitions in the decay. Both of the decay products of these isotopes fall into mass regions where the excited states can be represented, to first order, by collective vibrational harmonic oscillations about a spherical equilibrium nuclear shape. Measurements of M1 admixtures, into the pure E2 transitions predicted on the basis of a perfect harmonic oscillator model, are of value in comparison with theories including a pairing-plus-quadrupole force [54]. The results from the nuclear orientation experiments are compared with similar measurements by the gamma-gamma correlation technique, and are found to be in general agreement, with frequently a much improved accuracy. The results, particularly for 110Cd suggest large perturbations of simple harmonic oscillator excitations. Previous nuclear orientation experiments on these isotopes hare suffered from an inaccurate, and often very wrong, value for the hyperfine interaction, due to a non-unique distribution of hyperfine fields in the alloys used. The comparison with the nuclear magnetic resonance experiments has enabled good alloys, with impurity concentrations less than 10-3 at %, to be used, and the distribution of hyperfine fields in more concentrated, and non-substitutional alloys to be studied. The theoretical basis of the nuclear orientation, and the observation of nuclear magnetic resonance by the perturbation of the thermal equilibrium gamma-ray anisotropic distribution from a system of oriented nuclei, is discussed in chapter one. The cryogenic apparatus and the experimental procedure is discussed in chapter two, including nuclear magnetic resonance measurements on three simple systems Fe 60Co, Co 60Co, and Fe 96To. Nuclear magnetic resonance studies on impurities of silver, gold, and iridium are presented in chapters three, six and seven.