Glyoxylase II (Glo II, E.C. 3.1.2.6) catalyzes the hydrolysis of S-D-Lactoylglutathione (SLG) to D-Lactate and glutathione. This is the rate limiting step in the conversion of methylglyoxal to D-Lactate. The purpose of the present study was to determine whether or not a relationship exists between some naturally occuring metabolites and in vivo modulation of Glo II. We have observed a non-competitive inhibition (~ 45%) of Glo II in crude preparation of rat liver by GTP (0.3 mM). A factor (apparently protein),devoid of Glo II,when reconstituted with the purified Glo II, enhanced Glo II activity. This coordinate activation and inhibition of Glo II suggest a mechanism whereby SLG levels can be modulated in vivo.

dissertation submitted to the Faculty of Health Sciences, School of Therapeutic Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Occupational Therapy Johannesburg, 2017 / Parents of children who have sensory modulation disorder (SMD) and who have sensory over-responsiveness (SOR) themselves may display mal-adaptive self-regulatory strategies, contributing to elevated stress levels. The purpose of the study is to determine the perceived stress levels and sensory self-regulatory strategies of mothers of children with SMD, who presented with SOR themselves. A twelve-week stress management programme using a sensory modulation-based approach was developed and implemented with a sample of five mothers with SOR. The quasi-experimental pre-test post-test design required the participants to complete the Parenting Stress Index-4 Short Form and a sensory self-regulatory questionnaire. The effectiveness of the programme was assessed by determining change in perceived stress and self-regulatory behaviours immediately after and three months following the programme. Although no statistically significant change was found, clinically relevant change with large effect sizes was evident in the scores for parental distress, difficult child, total stress, and self-regulatory behaviour after the intervention period. Further clinical change was found for parental distress, difficult child and parent child dysfunctional interaction with moderate effect sizes after the follow up period. The results of this study indicate the importance of addressing the mother’s stress levels, in addition to treating their child with SMD. / MT2017

Typescript, etc.

This thesis describes modulated methods using both voltammetric and microfluidic perturbations to study mechanisms of electrolysis reactions. The initial chapters provide an overview of applications and research development in the fields of micro-engineering and electrochemistry, including microfabrication methodology, electrochemical detection techniques and analysis methods. Some typical electrochemical reactions have been studied for different kinds of industrial applications. Also hydrodynamic modulation methods have been investigated. The result chapters begin in Chapter 3 with detailed investigation of various electrochemical reactions by using cyclic voltammetry (CV) and large amplitude Fourier transformed alternating current voltammetry (FTACV) under microfluidic conditions. Single electron transfer reactions with different kinetics were studied first by using potassium ferrocyanide and ferrocenecarboxylic acid (FCA). Dual electron transfer reactions with different pathways were investigated by using 2,5-dihydroxybenzoic acid for one step oxidation and N,N,N',N'-tetramethyl-para-phenylene-diamine (TMPD) for two consecutive one-electron step oxidation. An irreversible reaction was explored by using borohydride solution. Examples of homogeneous reaction mechanisms were studied by using the combinations of Fe(CN)64-/L-cysteine or TMPD/ascorbic acid. The current response of all the electrolysis reactions except single electron transfer reactions was first reported under microfluidic conditions with FTACV, which has shown sensitive with the change of volume flow rates and the substrate concentrations when homogeneous reactions are involved. The linear relationships between peak current and volume flow rates or substrate concentrations can be obtained in every harmonic component. In chapter 4, the modulated technique was applied to microfluidic hydrodynamic systems. A range of electrolysis mechanisms including single electron transfer reactions, dual electron transfer reactions, irreversible reaction and homogeneous reactions were studied under hydrodynamic modulated conditions. The system showed rapid response with the change of volume flow rates during one measurement. The linear relationships between peak current and flow rates, as well as substrate concentrations, can be obtained simultaneously in one scan, which reveals a promising approach to get more information in a short-time measurement. Chapter 5 demonstrated a new protocol by forcing an oscillation of the electrochemical active solution flowing. Analysis of transition time and its effect on limiting current are presented to begin exploration of this new tool for supporting researchers on understanding redox mechanisms. A short simulated study was carried out to help better understand the mechanism under different hydrodynamic conditions.

Pun Siu Sun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 55-58). / Abstract in English and Chinese. / ABSTRACT --- p.ii / 摘要 --- p.iv / Chapter 1 --- BLACKGROUND AND INTRODUCTION --- p.1 / Chapter 1.1 --- OPTICAL FREQUENCY SHIFT KEYING (FSK) --- p.1 / Chapter 1.1.1 --- Basic concepts --- p.1 / Chapter 1.1.2 --- Applications --- p.3 / Chapter 1.2 --- MODULATION FORMATS --- p.6 / Chapter 1.3 --- ORTHOGONAL MODULATION --- p.9 / Chapter 1.4 --- THESIS ORGANIZATION --- p.11 / Chapter 2 --- A NOVEL OPTICAL FREQUENCY SHIFT KEYING TRANSMITTER BASED ON POLARIZATION MODULATION --- p.12 / Chapter 2.1 --- EXISTING OPTICAL FSK TRANSMITTER DESIGNS --- p.12 / Chapter 2.1.1 --- Optical FSK transmitter based on complementary intensity modulation --- p.12 / Chapter 2.1.2 --- Optical FSK transmitter based on direct modulation in a DFB laser --- p.13 / Chapter 2.1.3 --- Optical FSK transmitter based on single side-band (SSB) modulation technique --- p.15 / Chapter 2.1.4 --- Optical Continuous-Phase FSK (CPFSK) transmitter based on asymmetric Mach-Zehnder modulator --- p.17 / Chapter 2.1.5 --- Optical FSK transmitter based on phase modulation --- p.18 / Chapter 2.1.6 --- Summary --- p.20 / Chapter 2.2 --- PROPOSED OPTICAL FSK TRANSMITTER BASED ON POLARIZATION MODULATION --- p.21 / Chapter 2.3 --- EXPERIMENTAL DEMONSTARTION --- p.23 / Chapter 2.4 --- SYSTEM PERFORMANCE --- p.25 / Chapter 2.5 --- SUMMARY --- p.27 / Chapter 3 --- OPTICAL RETURN-TO-ZERO FREQUENCY SHIFT KEYING (RZ-FSK) (RZ-FSK) --- p.28 / Chapter 3.1 --- INTRODUCTION AND MOTIVATION --- p.28 / Chapter 3.2 --- PREVIOUS NRZ vs. RZ COMPARISON --- p.30 / Chapter 3.3 --- RZ-FSK TRANSMITTER DESIGN --- p.32 / Chapter 3.4 --- PERFROMANCE COMPARISON --- p.33 / Chapter 3.4.1 --- Back-to-back performance --- p.34 / Chapter 3.4.2 --- Chromatic dispersion tolerance --- p.35 / Chapter 3.4.3 --- Fiber nonlinearity tolerance --- p.38 / Chapter 3.5 --- SUMMARY --- p.41 / Chapter 4 --- A NOVEL OPTICAL TRANSMITTER FOR HIGH-SPEED DIFFERENTIAL PHASE SHIFT KEYING/INVERSE RETURN-TO-ZERO (DPSK/INV-RZ) ORTHOGONALLY MODULATED SIGNALS --- p.42 / Chapter 4.1 --- INTRODUCTION --- p.42 / Chapter 4.2 --- PREVIOUS SCHEME --- p.43 / Chapter 4.3 --- PROPOSED TRANSMITTER DESIGN --- p.45 / Chapter 4.4 --- EXPERIMENT AND RESULTS --- p.47 / Chapter 4.5 --- CONCLUSION --- p.51 / Chapter 5 --- SUMMARY --- p.52 / Chapter 5.1 --- THESIS SUMMARY --- p.52 / Chapter 5.2 --- FUTURE WORK --- p.53 / LIST OF PUBLICATIONS --- p.54 / REFERENCES --- p.55

No description available.

Viscosity is an important parameter in fluid dynamics. Although many conventional techniques are useful in determining a limited range of liquid viscosity with high accuracy, non-invasive measurement techniques for a broader range of viscosity are yet to be developed. The subjects on viscosity are advancing rapidly partly due to the development and applications of microfluidic. In anticipation of such developments, we are proposing a new method of viscosity measurement in the micrometer scale that is simple, non-invasive, real-time, wide dynamics range, and with imaging capability. This method relies on successful integration of laser scanning confocal microscopy, lock-in amplification, and variable galvono-scanning. It also has the potential to be a powerful tool in biology and medicine. The principle of operation is based on modulation microscopy that employs confocal configuration in detecting the deformation and phase delay of the forced oscillating sample.

The thesis focuses on the study of asymmetric multiple quantum wells (AMQWs). There are two main sources of the samples. One is from our laboratory. We used molecular-beam epitaxy to grow the InGaAs/InGaAlAs AMQWs of different well widths and different position arrangement of well width. And we also designed the AMQWs with p-type modulation doping at the different barrier region. The other is from Land Mark Optoelectronics Corporation. They used Metalorganic Chemical Vapor Deposition (MOCVD) to grow the InGaAsP AMQWs of different well widths and different position arrangement of well width. There are five experiments in my thesis. First of all, we use electroluminescence (EL) measurement to discuss the EL spectra of the samples. The EL spectra can show the shape, intensity and full width half maximum. Second, we use the photoreflectance (PR) measurement, which uses laser beam to modulate the dielectric constant of samples, to discuss the transition energies by using simulation and curve fitting. And we got build-in electric field from FKO data and simulation. In the last three experiments, we analyzed photocurrent spectra, photoluminescence spectra and electro-absorption spectra individually and then compared the three to all experiments in the thesis. In these experiments, we discovered that the sample C092 exhibits a broad and flat EL spectrum and 2500Å covering from 1.38~1.63£gm. Besides, we also found that the emission of wells is dominated by the arrangement of quantum wells. Moreover, the arrangement of quantum wells is relative to material. Therefore, even if we use the same way of arrangement, the different materials will lead to different results. Finally, we expect that we can use our AMQWs samples to produce broadly tunable laser and broad-band semiconductor optical amplifier (SOA) in the future.

This thesis utilized the characteristics of the external cavity system including the wavelength tuning and the multi-channel output, and using the Quantum Confined Stark Effect (QCSE) by adding the bias on the electro-absorption modulator to build a new method of the Q-switched modulation .The method made the wavelength tuning and multi-channel output of high speed Q-switched external cavity semiconductor laser with the colinear output come true . The system of the external cavity semiconductor laser with the electro-absorption modulator making of the VCSEL with the wavelength 850nm and 830nm could be modulated to 63ns . The tuning range could be up to 0.9nm . Each of the channel would be separated into 0.2nm . We could obtain the two channels output by using the double electro-absorption modulators on the specific position .The distance of the wavelength is 4.61nm.

Previous research has indicated that the amygdala exerts a modulatory influence on multiple memory systems. Evidence also indicates that emotional state can influence the use of multiple memory systems and that this effect is mediated by the amygdala. Anxiogenic drugs administered during acquisition in a task that can be acquired either through hippocampus-dependent “place” learning or caudate dependent “response” learning, resulted in the predominant use of response learning. It is not known whether inducing anxiety at other behavioral time points will also influence the relative use of multiple memory systems. In experiment 1, male Long-Evans rats were trained to swim from the same start point to an escape platform constantly located in a goal arm. Prior to memory retrieval rats were administered either alpha- two adrenoceptor antagonist RS 79948-197, peripherally (0.03, 0.01, 0.3 mg/kg) or into the basolateral amygdala (0.1 µg), or saline vehicle. Rats treated with RS 79948-197 prior to memory retrieval exhibited caudate-dependent response learning. Previous studies examining the effects of RS 77948-197 on memory were conducted with rats trained in an anxiogenic state and subsequently probed in a drug free state. Experiment 2 examined whether state dependency may account for those results. Animals received peripheral (0.1 mg/kg) or intra-amygdala (0.1 µg) administration of RS 79948-197, prior to both acquisition and memory retrieval. Rats treated with RS 79948- 197 predominantly exhibited response learning. Finally, experiments 3 and 4 examined whether the use of response learning produced by RS79948-197 was due to the impairing effect on hippocampus-dependent memory. Rats that were administered peripheral (0.03 mg/kg) or intra-amygdala (0.1 µg) injections of RS 79948-197 displayed impaired acquisition of the single solution place task relative to control animals. This indicates that place learning was impaired. Over, all the present findings indicate 1) peripheral and intra-amygdala anxiogenic drug administration results in the use of habit memory at both acquisition and retrieval, 2) state dependency does not play a role in the influence of RS 799948-197 on memory system use, 3) the use of response learning produced by peripheral and intra-amygdala injections of RS 79948-197 may result from an impairing effect of hippocampusdependent memory.