Physical Property Control In Core/Shell Inorganic Nanostructures For Fluorescence And Magnetic Targeting Applications

Nanomaterials show immense promise for the future in numerous areas of application. Properties that are unique from the bulk material and are tunable allow for innovation in material design. This thesis will focus on controlling the physical properties of core/shell nanostructures to enhance the utility of the materials. The first focus is on the impact of different solvent mixtures during the shell growth phase of SILAR based core/shell quantum dot synthesis is studied. Gaining insight into the mechanism for SILAR growth of core/shell nanoparticles allows improved synthetic yields and precursor binding, providing enhanced control to synthesis of core/shell nanoparticles. The second focus of this thesis is exploring the use of magnetic nanoparticles for magnetic drug targeting for to reduce the negative impact of cardiovascular conditions. Magnetic targeting for drug delivery enables increased local drug concentration, while minimizing non-specific interactions. In order to be effective for magnetic targeting, it must be shown that low magnetic strength is sufficient to capture flowing nanoparticles. By demonstrating the binding of a therapeutic agent to the surface at medicinal levels, the viability for use as a nanoparticle drug delivery system is improved

Loyalty Among Relationally Oriented Customers: Not Just an Issue of Managing Satisfaction: Working Paper Series--02-27

This paper explores empirically the relative impacts of satisfaction, brand community, and consumer experience on customer loyalty as expressed by future purchase intentions. Data drawn from qualitative research and a survey of relationally-oriented customers in a casino setting indicate that satisfaction yields to brand community as a key driver of loyalty. Important implications of this research for theory as well as marketing practice are discussed

Magnetic Monopole Noise

Magnetic monopoles are hypothetical elementary particles exhibiting quantized magnetic charge $m_0=\pm(h/\mu_0e)$ and quantized magnetic flux $\Phi_0=\pm h/e$. A classic proposal for detecting such magnetic charges is to measure the quantized jump in magnetic flux $\Phi$ threading the loop of a superconducting quantum interference device (SQUID) when a monopole passes through it. Naturally, with the theoretical discovery that a plasma of emergent magnetic charges should exist in several lanthanide-pyrochlore magnetic insulators, including Dy$_2$Ti$_2$O$_7$, this SQUID technique was proposed for their direct detection. Experimentally, this has proven extremely challenging because of the high number density, and the generation-recombination (GR) fluctuations, of the monopole plasma. Recently, however, theoretical advances have allowed the spectral density of magnetic-flux noise $S_{\Phi}(\omega,T)$ due to GR fluctuations of $\pm m_*$ magnetic charge pairs to be determined. These theories present a sequence of strikingly clear predictions for the magnetic-flux noise signature of emergent magnetic monopoles. Here we report development of a high-sensitivity, SQUID based flux-noise spectrometer, and consequent measurements of the frequency and temperature dependence of $S_{\Phi}(\omega,T)$ for Dy$_2$Ti$_2$O$_7$ samples. Virtually all the elements of $S_{\Phi}(\omega,T)$ predicted for a magnetic monopole plasma, including the existence of intense magnetization noise and its characteristic frequency and temperature dependence, are detected directly. Moreover, comparisons of simulated and measured correlation functions $C_{\Phi}(t)$ of the magnetic-flux noise $\Phi(t)$ imply that the motion of magnetic charges is strongly correlated because traversal of the same trajectory by two magnetic charges of same sign is forbidden

Dental needs of intellectually disabled children attending six special educational facilities in Cape Town

OBJECTIVE. To assess the dental needs of a group of children with intellectual disability (ID) attending six special educational facilities in Cape Town, South Africa. METHODS. This was a cross-sectional study based on a convenience sampling method. One hundred and fifty-seven children with ID attending six special educational facilities in Cape Town were included in the survey. Five schools were exclusively funded by the State and one school received additional private financial support. The oral examinations complied with guidelines drafted by Special Olympics Special Smiles programme and the Centers for Disease Control, USA. RESULTS. The most common dental disorders requiring management were gingival disease (69%) and untreated dental caries (68%). Almost 50% of the children had missing teeth. Twenty-nine percent needed orthodontic correction of malocclusion and 7% had structural abnormalities of their teeth that required either aesthetic or functional intervention. Fillings were evident in only 8% of the children. Females required more dental treatment than males. The dental needs of children with ID increased with age. There were no significant differences in the dental needs of children attending State-funded schools and those attending the single school that received additional financial assistance. CONCLUSION. The frequency of unmet dental needs of children with ID attending special educational facilities in Cape Town was high and the dental care available to them was minimal. The study highlights the need for improved dental services to ensure that optimal oral health is accessible to children with ID attending special educational facilities in Cape Town.DHE

Rubinstein-Taybi syndrome:dental manifestations and management

Rubinstein-Taybi syndrome (RSTS) is an uncommon genetic disorder characterised by a typical facies, small stature, broad angulated thumbs and intellectual impairment. Dental changes are a minor, yet significant component of the condition. Craniofacial growth retardation in RSTS is frequently complicated by unerupted teeth, while dental caries is related to the inherent intellectual deficit. Dental problems necessitate interdisciplinary management in terms of oral surgery, conservative dentistry, periodontics and orthodontics. When affected individuals are unco-operative, certain dental procedures may warrant general anaesthesia. In these instances, dental and medical staff will combine their expertise to enhance the well-being of the patient. In addition, specific dental changes may alert the medical practitioner to the possible diagnosis of RSTS. In this article we document the oro-dental manifestations and review the oro-dental approach in the management of three patients with RSTS. Our experience in South Africa may be relevant to other countries at a similar stage of development

What children know about the source of their knowledge without reporting it as the source

We argue that, amongst 3- to 5- year-olds, failure to report the source of knowledge recently acquired in answer to “How do you know…?” is due to a specific failure to make a causal inference, in line with source monitoring theory but not fuzzy trace theory. In three Experiments, children (N = 37; 30; 59) identified a hidden toy by seeing, feeling, or by being told, having had two modes of access on each trial, one informative (e.g. seeing a toy identified by colour) and the other uninformative (e.g. being told the toy’s colour by the Experimenter who had only felt it). Children who answered the know question wrongly nevertheless reported accurately who saw and who felt the toy, and what the well-informed player had said. They also realised when the Experimenter’s uninformative access implied their own knowledge was unreliable, suggesting precocious working understanding of knowledge sources

Developmental changes in spinal neuronal properties, motor network configuration, and neuromodulation at free-swimming stages of Xenopus tadpoles

We describe a novel preparation of the isolated brainstem and spinal cord from pro-metamorphic tadpole stages of the South African clawed frog (Xenopus laevis) that permits whole cell patch-clamp recordings from neurons in the ventral spinal cord. Previous research on earlier stages of the same species has provided one of the most detailed understandings of the design and operation of a CPG circuit. Here we have addressed how development sculpts complexity from this more basic circuit. The preparation generates bouts of fictive31 swimming activity either spontaneously or in response to electrical stimulation of the optic tectum, allowing an investigation into how the neuronal properties, activity patterns and neuromodulation of locomotor rhythm generation change during development. We describe an increased repertoire of cellular responses compared to younger larval stages and investigate the cellular level effects of nitrergic neuromodulation as well as the development of a sodium pump-mediated ultra-slow afterhyperpolarisation (usAHP) in these free-swimming larval animals.PostprintPeer reviewe