Determining the Critical Window of Influence of PCB Perinatally on Behavioral and Hormonal Development in Sprague-Dawley Rat Pups

Polychlorinated biphenyls (PCB) had widespread use in the United States in commercial manufacturing in the United States until the late 1970s. Even though they were banned, measurable amounts can still be found in the environment and food sources. PCB has known effects on altering hormone development and behavior in the species Rattus norvegicus. To determine the most crucial developmental time of exposure to PCB in Sprague-Dawley rat pups, rat pups were exposed to PCB at differing weeks of either gestation period or the first postnatal week. Behavioral tests were performed for the different rat pups, as well as blood serum was analyzed for the concentration of thyroid hormone. This paper presents data for PCB exposed pups that were tested for play behavior on PND 22. Statistical tests were used to determine the week of PCB exposure with the greatest effects on the rat pups. The results are that exposure of PCB led to a significant increase in the play behavior of the pups. The dorsal contact play behavior was significantly altered by PCB, while the pin behavior was not significantly altered. The critical window for PCB exposure was not identified, but it can be seen that PCB alters dorsal contact behavior in exposed rat pups

Using Molecular Structure to Tune Intrachain and Interchain Charge Transport in Indacenodithiophene-Based Copolymers.

In this work, we compare two structurally near-amorphous rigid-rod polymers─poly(indacenodithiophene-co-benzothiadiazole), p(IDT-BT), and poly(indacenodithiophene-co-benzopyrollodione), p(IDT-BPD)─with orders of magnitude different mobilities to understand the effect charge carrier intrachain delocalization has on electronic transport. Quantum chemical calculations show that p(IDT-BPD) has a barrier to torsion that is significantly lower than that of p(IDT-BT) and is thus more likely to have reduced conjugation lengths. We utilize absorption and photoluminescence spectroscopy to characterize energetic disorder and show that p(IDT-BPD) has higher energetic disorder. Charge modulation spectroscopy (CMS) and model calculations are used to show that charge carriers are substantially delocalized in p(IDT-BT) and occupy near-uniform energetic environments. We find that mobility activated hopping barriers are similar in these two materials. Electronic structure calculations show that both intrachain and interchain couplings of monomer units are poor enough in p(IDT-BPD) that charge carriers collapse to single IDT units and transport via a through-space tunneling mechanism. This work highlights the remarkable charge transport properties of p(IDT-BT) by showing that high mobilities are achievable on device-relevant length scales with only 1D carrier delocalization

An investigation into the use of social network sites to support project communications

System deployment projects are extremely complex and with more and more organisations now choosing to configure and deploy off-the-shelf systems, the project teams are presented with new challenges. The aim of this study was to gain an understanding of the issues faced during such configuration and deployment projects and see if support could be provided. A year long observational study of one of these projects was carried. While it was initially assumed that it would be technical issues related to the system’s configuration that would be the primary problems, the study revealed communication issues to be at the heart of a large number of the issues. Online social networks such as Facebook are extremely popular, allowing users to stay in touch with large numbers of distributed people. Private social network sites were applied to projects to see if they could replicate the benefits the sites provide and support project communications. A social network site was created for both a distributed research project and an administrative systems project and their use observed. Statistical data on the use of the sites and qualitative feedback from users is presented to assess the viability of the approach. The experiments showed social network sites to have many benefits when used as a complementary mechanism to traditional channels for project communications. It is clear however, that social network sites cannot solve all the problems projects may encounter. If the use of a site is to be a success it is vital it gains a critical mass of users. The approach taken to the site’s configuration and introduction will be hugely influential in its success. In order to choose the right approach a clear understanding of what the project’s communication needs are and the possible uses of the site is needed. A process of configuration and development with a small group of potential users is recommended to ensure it is as user friendly as possible before going live to a large user base.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Conscious sedation reduces distress in children undergoing voiding cystourethrography and does not interfere with the diagnosis of vesicouteric reflux: a randomized controlled study

OBJECTIVE. Voiding cystourethrography (VCU) is a distressing procedure for children. Conscious sedation using oral midazolam may reduce this distress, but its use may also alter the ability of the VCU to show vesicoureteric reflux (VUR). The objectives of our study were to assess the effectiveness of conscious sedation using oral midazolam when administered routinely in children undergoing VCU and to ensure that conscious sedation using oral midazolam does not alter the ability of VCU to show VUR

Observations of the Scottish elections 2007

<p><i>Purpose</i> – The purpose of this paper is to provide an observational examination of the recent Scottish elections, within which an e-counting system was employed to manage the increased complexity of the Scottish electoral system for the first time.</p> <p><i>Design/methodology/approach</i> – Observations of an ethnographic nature, supplemented by written documentation used for both training and public consumption during the Scottish election process.</p> <p><i>Findings</i> – It was found that the voting system for the Scottish elections had not received sufficient review or testing prior to the election; further that the design choices imposed by the DRS software did not support the actions of its users efficiently enough, or justify confidence in the dependability of the system.</p> <p><i>Practical implications</i> – That the deployment of e-counting systems requires careful consideration; many of the issues raised in this paper are similar to those of the official Scottish Elections Review, to which our team provided input.</p> <p><i>Originality/value</i> – The Scottish elections were the first to allow members of the public to register as election observers, accredited by the Electoral Commission. As such, the Scottish elections represented the first large-scale opportunity to observe such processes for the academic community.</p&gt

Influence of Side Chain Interdigitation On Strain and Charge Mobility of Planar Indacenodithiophene Copolymers

Indacenodithiophene (IDT) copolymers are a class of conjugated polymers that have limited long-range order and high hole mobilities, which makes them promising candidates for use in deformable electronic devices. Key to their high hole mobilities is the coplanar monomer repeat units within the backbone. Poly(indacenodithiophene-benzothiadiazole) (PIDTC16-BT) and poly(indacenodithiophene-thiapyrollodione) (PIDTC16-TPDC1) are two IDT copolymers with planar backbones, but they are brittle at low molecular weight and have unsuitably high elastic moduli. Substitution of the hexadecane (C16) side chains of the IDT monomer with isocane (C20) side chains was performed to generate a new BT-containing IDT copolymer: PIDTC20-BT. Substitution of the methyl (C1) side chain on the TPD monomer for an octyl (C8) and 6-ethylundecane (C13B) afford two new TPD-containing IDT copolymers named PIDTC16-TPDC8 and PIDTC16-TPDC13B, respectively. Both PIDTC16-TPDC8 and PIDTC16-TPDC13B are relatively well deformable, have a low yield strain, and display significantly reduced elastic moduli. These mechanical properties manifest themselves because the lengthened side chains extending from the TPD-monomer inhibit precise intermolecular ordering. In PIDTC16-BT, PIDTC20-BT and PIDTC16-TPDC1 side chain ordering can occur because the side chains are only present on the IDT subunit, but this results in brittle thin films. In contrast, PIDTC16-TPDC8 and PIDTC16-TPDC13B have disordered side chains, which seems to lead to low hole mobilities. These results suggest that disrupting the interdigitation in IDT copolymers through comonomer side chain extension leads to more ductile thin films with lower elastic moduli, but decreased hole mobility because of altered local order in the respective thin films. Our work, thus, highlights the trade-off between molecular packing structure for deformable electronic materials and provides guidance for designing new conjugated polymers for stretchable electronics