Theta-modulated place-by-direction cells in the hippocampal formation in the rat

We report the spatial and temporal properties of a class of cells termed theta-modulated place-by-direction (TPD) cells recorded from the presubicular and parasubicular cortices of the rat. The firing characteristics of TPD cells in open-field enclosures were compared with those of the following two other well characterized cell classes in the hippocampal formation: place and head-direction cells. Unlike place cells, which code only for the animal's location, or head-direction cells, which code only for the animal's directional heading, TPD cells code for both the location and the head direction of the animal. Their firing is also strongly theta modulated, firing primarily at the negative-to-positive phase of the locally recorded theta wave. TPD theta modulation is significantly stronger than that of place cells. In contrast, the firing of head-direction cells is not modulated by theta at all. In repeated exposures to the same environment, the locational and directional signals of TPD cells are stable. When recorded in different environments, TPD locational and directional fields can uncouple, with the locational field shifting unpredictably ("remapping"), whereas the directional preference remains similar across environments

The molecular biology of feline immunodeficiency virus (FIV).

Feline immunodeficiency virus (FIV) is widespread in feline populations and causes an AIDS-like illness in domestic cats. It is highly prevalent in several endangered feline species. In domestic cats FIV infection is a valuable small animal model for HIV infection. In recent years there has been sa significant increase in interest in FIV, in part to exploit this, but also because of the potential it has as a human gene therapy vector. Though much less studied than HIV there are many parallels in the replication of the two viruses, but also important differences and, despite their likely common origin, the viruses have in some cases used alternative strategies to overcome similar problems. Recent advances in understanding the structure and function of FIV RNA and proteins and their interactions has enhanced our knowledge of FIV replication significantly, however, there are still many gaps. This review summarizes our current knowledge of FIV molecular biology and its similarities with, and differences from, other lentiviruses

Impurity free vacancy disordering of InGaAs quantum dots

The effect of thermal interdiffusion on In(Ga)As∕GaAsquantum dot structures is very significant, due to the large strain and high concentration of indium within the dots. The traditional high temperature annealing conditions used in impurity free vacancy disordering of quantum wells cannot be used for quantum dots, as the dots can be destroyed at these temperatures. However, additional shifts due to capping layers can be achieved at low annealing temperatures. Spin-on-glass, plasma enhanced chemical vapor depositedSiO₂, Si₃N₄, and electron-beam evaporated TiO₂ layers are used to both enhance and suppress the interdiffusion in single and stacked quantum dot structures. After annealing at only 750°C the different cappings enable a shift in band gap energy of 100meV to be obtained across the sample

Effects of rapid thermal annealing on device characteristics of InGaAs/GaAs quantum dot infrared photodetectors

In this work, rapid thermal annealing was performed on InGaAs/GaAs quantum dot infrared photodetectors (QDIPs) at different temperatures. The photoluminescence showed a blueshifted spectrum in comparison with the as-grown sample when the annealing temperature was higher than 700 °C, as a result of thermal interdiffusion of the quantum dots (QDs). Correspondingly, the spectral response from the annealed QDIP exhibited a redshift. At the higher annealing temperature of 800 °C, in addition to the largely redshifted photoresponse peak of 7.4 µm (compared with the 6.1 µm of the as-grown QDIP), a high energy peak at 5.6 µm (220 meV) was also observed, leading to a broad spectrum linewidth of 40%. This is due to the large interdiffusion effect which could greatly vary the composition of the QDs and thus increase the relative optical absorption intensity at higher energy. The other important detector characteristics such as dark current, peak responsivity, and detectivity were also measured. It was found that the overall device performance was not affected by low annealing temperature, however, for high annealing temperature, some degradation in device detectivity (but not responsivity) was observed. This is a consequence of increased dark current due to defect formation and increased ground state energy. © 2006 American Institute of Physic

Comparing Online and Offline Knowledge Networks of Carbon Capture and Storage

© 2017 The Authors. This paper examines the complex ecosystem of organisations involved in the proposed role out of carbon capture and storage (CCS) in the UK. Through analysis of interview and twitter data, it focuses on the flow of knowledge flows within online and offline networks, highlighting how in this case, CCS retains a niche audience, with communication and information flows concentrated with industry and stakeholder networks at a local and regional scale, as opposed to reaching broader national policy makers, and the wider publics. This brings a unique insight into the construction of networks across intersecting sectors of this critical technology and highlights how for successful implementation CCS, actors may need to reach out beyond their existing network

Exercise Beliefs and Behaviours of Individuals with Joint Hypermobility Syndrome/ Ehlers Danlos Syndrome-Hypermobility Type

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Disability & Rehabilitation on 10 November 2017, available online at: https://doi.org/10.1080/09638288.2017.1398278. © 2017 Informa UK Limited, trading as Taylor & Francis GroupPurpose: To explore exercise beliefs and behaviours of individuals with Joint Hypermobility syndrome/Ehlers–Danlos syndrome – hypermobility type and to explore patient experiences of physiotherapy.Methods: A cross sectional questionnaire survey design was used to collect quantitative and qualitative data from adult members of the Hypermobility Syndromes Association and Ehlers–Danlos Syndrome Support UK. Descriptive and inferential statistics were used to analyse the data. Qualitative data was analysed thematically.Results: 946 questionnaires were returned and analysed. Participants who received exercise advice from a physiotherapist were 1.75 more likely to report high volumes of weekly exercise (odds ratio [OR] = 1.75, 95% confidence interval [CI] = 1.30–2.36, p < 0.001) than those with no advice. Participants who believed that exercise is important for long-term management were 2.76 times more likely to report a high volume of weekly exercise compared to the participants who did not hold this belief (OR = 2.76, 95% CI = 1.38–5.50, p = 0.004). Three themes emerged regarding experience of physiotherapy; physiotherapist as a partner, communication – knowledge, experience and safety.Conclusion: Pain, fatigue and fear are common barriers to exercise. Advice from a physiotherapist and beliefs about the benefits of exercise influenced the reported exercise behaviours of individuals with Ehlers–Danlos syndrome – hypermobility type in this survey.Peer reviewe

Evaluating RNA Structural Flexibility: Viruses Lead the Way.

Our understanding of RNA structure has lagged behind that of proteins and most other biological polymers, largely because of its ability to adopt multiple, and often very different, functional conformations within a single molecule. Flexibility and multifunctionality appear to be its hallmarks. Conventional biochemical and biophysical techniques all have limitations in solving RNA structure and to address this in recent years we have seen the emergence of a wide diversity of techniques applied to RNA structural analysis and an accompanying appreciation of its ubiquity and versatility. Viral RNA is a particularly productive area to study in that this economy of function within a single molecule admirably suits the minimalist lifestyle of viruses. Here, we review the major techniques that are being used to elucidate RNA conformational flexibility and exemplify how the structure and function are, as in all biology, tightly linked

Designing and optimizing a micromanipulator-controlled surgical tool for reproducible nerve crush injuries in mice

Poster presented at the 2017 Health Sciences Research Day which was organized and sponsored by the University of Missouri School of Medicine Research Council and held on November 9, 2017.Introduction: Recurrent laryngeal nerve (RLN) injury, even if temporary, is a devastating complication of anterior cervical surgical procedures, resulting in debilitating dysphonia and dysphagia. During surgery, injury can be imparted by stretching, crushing, cauterizing, and/or transecting the laryngeal nerves. The injury can be temporary or permanent, depending on the severity and mechanism of insult. Treatment of the injury is generally palliative in nature and includes feeding tubes, voice and swallowing therapy, and diet modifications. The underlying pathophysiology of RLN is not completely understood. To effectively investigate various treatment strategies in mouse models, we need to improve the current translational animal model by standardizing the widely-used manual nerve crush techniques that apply variable force and may unintentionally add traction injuries. To control for these potential confounds, we are developing a micromanipulator-controlled surgical tool that (1) reliably applies a calibrated crush force injury, and (2) minimizes secondary injuries, such as traction, induced by manual methods

Proton-irradiation-induced intermixing of InGaAs quantum dots

Proton irradiation was used to create interdiffusion in In₀.₅Ga₀.₅Asquantum dots(QDs), grown by low-pressure metalorganic chemical vapor deposition. After 25-keV proton irradiation, the QD samples were annealed at two temperatures (700 or 750 °C) for 30 s. It was found that much lower annealing temperatures were needed to recover the photoluminescence signals than in the quantum-well case. Large blueshifts (120 meV) and narrowing of the photoluminescence spectra were seen. Various doses (5×10¹³–1×10¹⁵ cm⁻²) and implant temperatures (20–200 °C) were used to study the interdiffusion processes in these samples. In QD samples, much lower doses were required to achieve similar energy shifts than reported in quantum-well samples