Due to the ever increasing dependency on existing wireless technologies and the growing usage of sophisticated wireless devices, the demand for bandwidth is rising exponentially. Also, the Federal Communications Commission (FCC) has reserved a considerable amount of spectrum for licensed users. As a result, the unlicensed spectrum usage is constrained to the overcrowded unlicensed spectrum. Various spectral management surveys have indicated inefficient spectrum utilization in the licensed spectral bands. The congested unlicensed spectrum and inefficiently used licensed frequency bands calls for an approach to use the available spectrum opportunistically. Therefore, the concept of "Spectrum Pooling", which is based on Dynamic Spectrum Access (DSA), was proposed to make the unused sections of licensed spectrum available to the unlicensed users. In Spectrum Pooling, an empty section of licensed spectrum is borrowed by a secondary user for certain period of time without interfering with the licensed user. Orthogonal Frequency Division Multiplexing (OFDM) is a transmission scheme that is a candidate for Spectrum Pooling since it is capable of forming an adaptive spectral shape that allows coexistence of licensed and unlicensed users while attemting to minimize any interference. Subcarriers in the OFDM signal can be deactivated to generate Non-Contiguous OFDM (NC-OFDM). Even though NC-OFDM allows efficient use of available spectrum, it causes out of band (OOB) radiation, which adversely affects the performance of adjacent user. This thesis presents two novel techniques for combat the effects of OOB radiation generated by NC-OFDM. The proposed techniques employ a filtering-based approach combined with the technique of windowing in order to suppress the unwanted sidelobes by around 35dB-40dB. The attenuation is achieved without affecting other transmission parameters of the secondary user significantly.

When a speaker is addressing an audience, a PA system consisting of a microphone and a loudspeaker is often used. If the microphone picks up too much of the loudspeaker energy, acoustic feedback in the form of an unwanted characteristic howling can occur. Limes Audio is a software company that specializes in improving sound quality in digital communications, mainly conference telephony, and has developed a reference product, the Magneto mixer, to demonstrate the capability of their software TrueVoice. The company now wishes to expand the field of usage for the Magneto mixer to enable it to work as a microphone mixer in PA scenarios, and for this, a feedback suppression feature is needed. This master’s thesis aims at surveying the market and the literature in the field and specifying the requirements for a feedback suppression feature. Three methods for suppressing howling feedback are evaluated through simulations and compared in terms of maximum stable gain (MSG) and subjective listening experience. The method that performed the best based on these criteria was acoustic feedback cancellation with a 5 Hz frequency shift on the loudspeaker signal. This method makes use of an adaptive filter to model the acoustic feedback path and to remove the feedback component from the microphone signal. In the simulations, the method was able to increase the stable gain by approximately 10 dB while maintaining a good sound quality. / När en talare talar för en publik används ofta ett PA system bestående av en mikrofon och en högtalare. Om mikrofonen tar upp för mycket av ljudet från högtalaren finns en överhängande risk för akustisk rundgång i form av ett karaktäristiskt oönskat tjut. Limes Audio är ett företag som utvecklar mjukvara för att förbättra ljudkvaliten i digital kommunikation, främst inom konferenstelefoni. De har utvecklat en demonstrationsprodukt, Magnetomixern, som kan användas som en konferenstelefon för att demonstrera deras programvara TrueVoice. Företaget önskar nu utveckla Magnetomixern till att även fungera som en ljudmixer för PA-scenarion, eller konferenstelefoni där intern ljudförstärkning i rummet behövs, och för detta behövs en funktion för att ta bort eventuell rundgång. Detta examensarbete har som mål att lägga grunden för en sådan funktion i Magnetomixern genom att undersöka marknaden och litteraturen på området. Tre metoder för att eliminera rundgång utvärderas i simuleringar och jämförs beträffande maximal stabil förstärkning (MSG) och subjektiv ljudkvalitet. Metoden ”Acoustic feedback cancellation” tillsammans med ett 5 Hz frekvensskifte på högtalarsignalen gav högst MSG och bäst ljudkvalitet. Metoden använder ett adaptivt filter för att approximera den akustiska återkopplingsvägen mellan högtalare och mikrofon samt tar bort rundgångskomponenter från mikrofonsignalen. I simuleringarna kunde metoden öka den maximala stabila förstärkningen med upp till 10 dB medan en god ljudkvalitet på talet bibehölls.

Immune tolerance to self antigens prevents the onset of autoimmune diseases such as Multiple Sclerosis (MS). There are three branches of tolerance which allow the auto-aggressive potential of T lymphocytes to be limited; these are death, anergy-adaptation and regulation. The main body of this work attempts to clarify a role for adaptation in maintaining the sensitivity of the autoreactive T cell repertoire below a ‘threshold for harm’ in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). The well defined myelin basic protein (MBP) Ac1-9 epitope altered peptide ligand (APL) system has been used to develop a model allowing the examination of mechanisms underlying the adaptation of cells. Previous data showed immunisation with the 4Lys (wild-type) epitope mediated disease whereas a superagonist APL with a tyrosine substitution at position 4 (4Tyr) did not, despite showing potency in vitro. This was shown to be a result of both activation induced cell death and adaptation. Here an in vitro model was developed using MBP-reactive TCR transgenic cells to make predictions about the mechanisms underlying adaptation. These data lead to the conclusion that T cells can adapt (become less sensitive) either before or after encounter with the wild-type peptide, leading to a reversal of their pathogenic potential. The MBP APL system and MBP reactive transgenic cells were also used to assess the contribution of epitope spreading in a relapsing-remitting (RR) model of EAE induced with proteolipid protein. The cells were tracked and changes in phenotype and behaviour were monitored. The data show that disease induced with one antigen can be manipulated with cells relevant to a different antigen and that bystander suppression may be an effective weapon in controlling the progression to RR-EAE.

Active fire protection systems are an essential fire safety management tool, particularly in potentially high financial and risk consequence scenarios. In the UK and Europe over recent decades regulatory changes have been successful in creating an environment in which more innovation can take place. Increased numbers of fixed firefighting system types are now available to the user. However, not all systems offered are equal in terms of; suitability, cost, maturity of supporting knowledge, and overall performance or in-service reliability. Understanding of the systems performance and its limitations and how to match this to the assessed fire risk is incomplete among users. Experts are observing increasing numbers of what they consider to be poor fixed firefighting system choices leading to weaker fire safety designs, which is a cause of concern. Therefore the research aim is to verify that these concerns are founded and, that being the case, to develop a decision support system and related supporting resources to further this aspect of fire safety education and enable users to make better informed system selections. Thus, the focus of this research has been to develop a fixed firefighting system selection tool to complement existing legislation, which incorporates logic, rules and fire safety educational resources in a variety of formats to aid the fire safety design process. A variety of largely heuristic techniques have been used to aggregate data to form knowledge to underpin fixed firefighting system selection tool. In this form, the tool has been validated by experts as being a useful resource. The developed tool also provides ample opportunity for useful ongoing future development. The work recognises that cost and benefit are critical in the selection process. Supporting resources have been incorporated into the tool to assist users in evaluating the levels of reliability they might expect from a system in their circumstances. This tool has now been exposed to a wider audience of experts as part of an evaluation process. Findings include: that the tool is an innovative approach to promoting good fire safety designs, the tool efficiently provides useful fire safety education to users and the developed supporting resources which consider firefighting system reliability are helpful. This thesis and reference papers summarise the key stages of this research and tool development. The thesis concludes by outlining the progress achieved by this work and recommendations arising.

Emotions remain notably underexplored in both criminology and prisons research. This thesis sets out to address this problem by centralizing the importance of emotions in prison: especially the way prisoners express and regulate their affective states. To collect the data, 25 male and 25 female prisoners were 'shadowed', observed and interviewed across two prisons (HMP Send and HMP Ranby). Based on these findings, this thesis describes the emotional world of prisoners and their various 'affective' strategies. The three substantive chapters reveal the textured layers and various emotional states experienced by prisoners: first, at the level of the self (psychological); second, as existing between groups (social emotions); and, third, in relation to the physical environment (spatial). An individual substantive chapter is dedicated to each of these three levels of analysis. A primary finding was the prevalence of a wide range of 'emotion management' strategies among prisoners. One such strategy was emotion suppression, which was extremely salient among both men and women. While this emotion suppression was, in part, a product of pre-prison experiences it was also strongly influenced by institutional practices. Importantly, there was a strong correlation between prisoners who suppressed emotions and who were subsequently involved in violence (towards others, or inflicted upon themselves). A second key finding was the wide range of emotions that exist within, and are shaped by, different prison spaces-previous accounts have described prison as emotionally sterile, or characterised by anxiety and fear but this study develops the idea that prisons have an 'emotional geography' or affective 'map'. The study findings have implications for the 'emotional survivability' of our prisons; the need to open legitimate channels for emotional expression; and designing prisoners that are supportive, safe and secure establishments for prisoners to live in.

Although tremor is one of the most common movement disorders, there are few effective tremor-suppressing options available to patients. One potential tremor-suppression device involves a wearable gyrostabilizer similar to those used to stabilize cameras. However, we do not currently know how to design a gyrostabilizer to suppress tremor in an optimal manner. To address this gap, we present a systematic investigation of how gyrostabilizer parameters affect tremor suppression in a single degree of freedom (DOF). A simple model of the hand with a single DOF at the wrist and a gyroscope mounted on the back of the hand was used to focus on the most basic effects. After demonstrating that a linearized version of the non-linear equations of motion provides an adequate approximation, we simulated the frequency response of the system (hand + gyroscope) to a tremorogenic input torque at the wrist. By varying system parameters one at a time, we determined the effect of individual parameters on the frequency response of the system. To minimize the bandwidth without adding significant inertia about the wrist joint, the inertia and spin speed of the flywheel should be as high as design constraints allow, whereas the distance from the wrist joint axis to the gyroscope, the precession stiffness, and the precession damping should be kept as low as possible. The results demonstrate the potential of gyroscopic tremor suppression and can serve as the foundation for further investigations of gyroscopic tremor suppression in the upper limb.

Curcumin is the yellow pigment found in the Indian spice curry. It has anti-inflammatory, ant-oxidant, anti-cancer, anti-viral, anti-bacterial and wound healing properties. It is widely used in industry for its flavor as a spice and as a coloring agent because of its brilliant yellow color. It is also used as a dye for textiles and as an additive to cosmetics. Dendritic cells (DCs) are the sentinels of the immune system and functions as the bridge between the innate and adaptive immune response. The effect of curcumin on DCs is poorly understood. A study shows curcumin prevents the immuno-stimulatory function of bone marrow-derived murine DCs, but no study examines the effects on human DCs. This study investigates the effects of curcumin on immature human DC maturation and function in response to immune stimulants lipopolysaccharide (LPS) and polyinosinic-polycytidylic acid (poly I:C). Human CD14+ monocytes isolated from the peripheral blood of donors are cultured with GM-CSF and IL-4 supplemented media to generate immature DCs. The cultures are treated with curcumin, stimulated with the above mentioned stimulants then functional assays performed. These assays include homotypic cluster formation, surface marker expression, cytokine production, chemotaxis, endocytosis, DC-induced allogeneic CD4+ T cell proliferation after mixed lymphocyte reaction, gene expression analysis and immuno-fluorescence labeling and imaging. Curcumin-induced changes in gene expression indicate the actin cytoskeleton signaling pathway is a target. Immuno-fluorescence labeling and imaging of f-actin was carried out. Curcumin reduces DC maturation in response to the stimulants used in the study. Expression of surface markers, cytokines and chemokines is reduced as well as DC-induced stimulation of allogeneic CD4+ cells after MLR. Curcumin prevents chemotaxis without affecting chemokine receptor expression and significantly reduces endocytosis in non-stimulated cells. Curcumin-treated DCs do not induce a Th1 or Th2 population in allogeneic MLR but induces a CD25+Foxp3+ regulatory cell population. Immuno-fluorescence imaging shows curcumin causes the cell to become more rounded. These data imply that curcumin inhibits f-actin polymerization and thereby prevents DC maturation and function in response to stimulation. This outlines a novel role for curcumin as an immune suppressant and shows its therapeutic potential as an anti-inflammatory agent.

Bandpass filtered transient-evoked otoacoustic emission (TEOAE) waveforms are composed of short-latency (SL) and long-latency (LL) portions. The LL portion has latency consistent with generation through linear coherent reflection at the tonotopic place on the basilar membrane. The short-latency (SL) portion occurs earlier in time and exhibits less compressive growth. Several mechanisms have been hypothesized to explain generation of the SL portion, including 2f1-f2 intermodulation distortion and coherent reflection basal to the tonotopic place. Two experiments were designed to examine the generation mechanism and generation location of the SL portion. Experiment 1 tests the hypothesis that the SL portion results from low-side, cubic intermodulation distortion. Experiment 2 determines the region along the basilar membrane at which the SL portion of the TEOAE is generated. The null hypothesis that the SL portion of the TEOAE is generated through low-side, cubic intermodulation distortion requires stimuli with broad frequency content. Stimulus energy at different frequencies (f1 and f2) is presumed to interact simultaneously across the cochlear partition, generating a distortion-source OAE. To test this hypothesis, OAEs were evoked using 2 kHz tone-bursts with durations spanning the time-frequency continuum between a click and a pure tone. As tone-burst duration increases, stimulus energy at the primary frequencies (f1 and f2) decreases and the input to any nonlinear distortion source is reduced. Accordingly, if generated through 2f1-f2 distortion, the magnitude of the SL portion of the TEOAE was expected to decrease as tone-burst duration increased. Results were inconsistent with generation of the SL portion through intermodulation distortion. As tone-burst duration increased, the SL portion remained present in the TEOAE. The presence of the SL portion influenced the level-dependency of TEOAE latency and magnitude to the same extent across all tone-burst durations. The region of generation along the cochlear partition of the SL portion has implications for the mechanism through which it is generated. Generation through low-side, cubic intermodulation distortion (2f1-f2) would occur near the f2 tonotopic place. If generation is through coherent reflection, a generation region basal to that of the tonotopic place is hypothesized. To determine the cochlear region where the SL portion is generated, TEOAEs were evoked by 2 kHz tone-bursts in the presence of different suppressor stimuli. The amount of suppression induced by each suppressor on the OAE was measured, and the suppressor frequency causing greatest suppression of a given portion of the TEOAE was interpreted as corresponding to that portion's generation place along the basilar membrane. For analysis purposes, the SL portion was divided into two SL time-windows (SL1 and SL2). The LL portion of the TEOAE was maximally suppressed by a 2.07 kHz tone, consistent with generation at the tonotopic place. Both SL components were generated basal to the tonotopic place. The later-occurring SL portion of the TEOAE (SL1) was generated between 1/4-1/3-octave basal to the tonotopic place while the earlier-occurring SL portion (SL2) was generated 3/5-octave basal to the tonotopic place. The generation region of the SL1 portion of the TEOAE was too apical to be consistent with generation through 2f1-f2 distortion. Although the generation region of the SL2 portion was what would be expected for a 2f1-f2 distortion-source OAE, the latency was too early. Generation of both SL portions may be explained through basal linear coherent reflection. Per this mode of generation, the SL1 and SL2 portions of the TEOAE each likely mirror the underlying mechanics at different regions along the cochlear partition.

Proper aeration of cavitating hydraulic equipment can greatly reduce cavitation intensity, noise, and damage. This thesis quantifies the benefit, in terms of damage and noise, from aerating six inch butterfly valve. The incipient damage level of cavitation was obtained for both aerated and non -ae ra ted conditions. The level is defined as one pit per square inch of a soft aluminum test specimen per one minute of operation. A description of the cavitation pits that occurred plus where they appeared is presented. A graph showing the aerated and non-aerated limits of incipient damage is given along with a table showing the percent reduct ion of damage from aeration. A graph and table are also given depicting the reduction in noise. The proper location of aeration ports to allow natural aeration is outlined .

Malignant mesothelioma (MM) is an aggressive tumour, which is highly associated with previous asbestos exposure and is resistant to most conventional anticancer therapies. Previous studies have used a mouse model of to 01 p effective approaches to induction of anti-tumour immunity using modification of tumour cells by the introduction of genetic constructs expressing genes such as that for B7-1 so that tumour growth can be inhibited in vivo. Transfectant clones, AC29 B7-7 and AC29 B7-6, which showed equal levels of expression of B7-1 but were markedly different in tumorigenicity were assessed using suppression subtractive hybridization (SSH) in order to isolate transcripts which may have been differentially expressed in the two clones. SSH allowed isolation of a number of cDNAs which were apparently differentially expressed in the cell lines. These required characterisation in order to determine their possible relevance to tumorigenicity. Two cDNAs designated as 7-7-76 and 7-7-43 had been isolated previously and the aim of this project was to characterise these cDNAs by sequencing, searching for their homology relationships and investigating gene expression profiles. Preliminary searches revealed that clone 7-7-43 had homology to cyclin-dependent kinase regulatory subunit 1 which plays a role in the cell cycle. On the other hand, clone 77-76 showed only homology to an EST of hypertension related protein and therefore, further investigation was required to obtain the identity of clone 7-7-76. The first part of this project was to in investigate and evaluate gene expression on clone 7-7-43, using both relative RT-PCR and Northern blotting.' In the second part of this project, a more intense study of clone 7-7-76 was conducted. Clone 7-7-76 was investigated for its homology relationships and its gene expression profile. / Results obtained from relative RT-PCR suggested no difference in the expression of the either eDNA clone (7-7-43 and 7-7-76) between the MM clones AC29 B7-6 and AC29 B7-7, the cells used to derive these clones by SSH. Therefore, it was concluded that neither clone 7-7-43 nor 7-7-76 was differentially expressed in MM cells of differing immuno enicit RACE was employed in order to derive a longer sequence of clone 7-7-76 and the newly derived sequence of 7-7-76 was again used to search for homologies using a wider range of sequences for human and other species. These investigations on clone 7-7-76 showed it to correspond to the sequence of human mitofusin 2 which is involved in determining mitochondrial morphology The results determined in this project suggest that clones 7-7-43 and 7-7-76 are not differentially expressed in the range of MM cell lines tested. The data have however highlighted the potential of the SSH technique to easily derive cDNA clones worthy of investigation, but underline the possibility of false positive clones being isolated. The need for an efficient, accurate screening procedure such as real-time PCR is acknowledged.