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

Experiences of intensive home treatment for a mental health crisis during the perinatal period: A UK qualitative study

Some women with severe perinatal mental health difficulties in England are cared for by acute home treatment services, known as Crisis Resolution Teams (CRTs), which provide short-term home-based treatment for adults experiencing a mental health crisis. Intensive home treatment has been trialed in a number of countries, but it is not known how well suited it is to the needs of perinatal women. This qualitative study aimed to explore how women and practitioners experience the provision of intensive home treatment for perinatal mental health problems. Semi-structured interviews were conducted with women who had received intensive home treatment in the perinatal period (n = 15), and focus groups were held with practitioners working in CRTs or in specialist perinatal mental health services (3 groups, n = 25). Data were analysed thematically. Women commonly found intensive home treatment problematic, experiencing it as intrusive and heavily risk-focused, with poor staff continuity and little tailoring to the perinatal context. However, women valued emotional support when provided, particularly when it had a perinatal focus, sometimes based on practitioners sharing their own experiences. Some women also appreciated avoiding hospital admission, but choice was often limited. Practitioners reported a lack of perinatal training among CRT staff and described difficulties tailoring treatment to perinatal women's needs. Currently, intensive home treatment, as offered by CRTs, may not be well suited to women with perinatal mental health difficulties. Findings suggest a need to develop community crisis responses that are better tailored to the needs of this population

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

The Need for Performance Standards in Preschools: Stealing Shamelessly from Comprehensive School Mental Health Literature

Young children are at-risk for developing significant mental health difficulties just as their older, school-aged peers. Preschool settings have increasingly attempted to proactively address early childhood socioemotional needs by expanding their prevention and intervention activities. A number of emerging best practices in promoting early childhood mental health have been proposed. However, there are no comprehensive performance standards for preschool mental health and limited guidance on how preschools can align themselves with best practices. This expansion in service scope parallels the development of Comprehensive School Mental Health Systems in K-12 schools. Resources and tools developed for K-12 educational settings may serve as a useful example for preschool mental health systems interested in quality comprehensive mental health care. This conceptual article will describe the prevalence of mental health difficulties in young children, review the current guidance on supporting mental health in young children, and provide support for adapting widely used K-12 school mental health performance standards to establish comprehensive standards for organizing and implementing high quality care systems in preschool settings

The majority of re-activatable latent HIV proviruses are genetically distinct with no evidence of ongoing evolution

Background Two mechanisms have been proposed to contribute in to the maintenance of the HIV latent reservoir: homeostatic proliferation of latently infected cells and low level viral replication in the lymphoid tissue. Here we studied the sequences of reactivatable latent viruses obtained from a stably treated patient to assess the importance of these mechanisms. Methods Resting CD4+ T cells were isolated at regular intervals from the patient, underwent limiting dilution, were activated and then co-cultured with SupT1-CCR5 cells for 21 days. The supernatant was harvested for viral RNA. Regions in gag and env were analysed by Sanger sequencing. To control for artefacts from culture and sequencing, SupT1-CCR5 cells were infected with NL4-3 and underwent the same limiting dilution, culture, and sequencing processes. Pairwise comparisons were performed to obtain p-distances. Each pair of patient derived viral sequences was considered distinct if the p-distance was higher than that of the corresponding region of the sequences from NL4-3 infected SupT1-CCR5 cells. To seek evidence of viral evolution, a consensus was created from the viral sequences obtained from the first sample and sequences from samples obtained subsequently were compared against this baseline consensus. Results We obtained 32 sequences of reactivated latent viruses from a single patient. 18 distinct sequences could be distinguished from the gag region. The remaining 14 sequences segregated into five groups. However, when the env regions of these 14 sequences were analysed, only one ‘clonal’ group of two sequences remained. 30/32 reactivated latent viruses were distinct. If the threshold p-distance for two sequences to be considered distinct was set at the maximal (rather than average) p-distance observed in the reference set, 26/32 of reactivated latent viruses would still be considered distinct. We have not observed any increase in p-distances over 28 weeks of sampling compared to the baseline samples to suggest of accumulation of mutations. Conclusion Our results show that the majority of reactivatable latent viruses are genetically distinct. Persistent viral evolution was not observed in the latent reservoir harboured in peripheral blood resting CD4+ T cells in this stably treated patient

Topical delivery of hexamidine

Hexamidine diisethionate (HEX D) has been used for its biocidal actions in topical preparations since the 1950s. Recent data also suggest that it plays a beneficial role in skin homeostasis. To date, the extent to which this compound penetrates the epidermis has not been reported nor how its topical delivery may be modulated. In the present work we set out to characterise the interaction of HEX D with the skin and to develop a range of simple formulations for topical targeting of the active. A further objective was to compare the skin penetration of HEX D with its corresponding dihydrochloride salt (HEX H) as the latter has more favourable physicochemical properties for skin uptake. Candidate vehicles were evaluated by in vitro Franz cell permeation studies using porcine skin. Initially, neat solvents were investigated and subsequently binary systems were examined. The solvents and chemical penetration enhancers investigated included glycerol, dimethyl isosorbide (DMI), isopropyl alcohol (IPA), 1,2-pentanol (1,2-PENT), polyethylene glycol (PEG) 200, propylene glycol (PG), propylene glycol monolaurate (PGML) and Transcutol®P (TC). Of a total of 30 binary solvent systems evaluated only 10 delivered higher amounts of active into the skin compared with the neat solvents. In terms of topical efficacy, formulations containing PGML far surpassed all other solvents or binary combinations. More than 70% of HEX H was extracted from the skin following application in PG:PGML (50:50). Interestingly, the same vehicle effectively promoted skin penetration of HEX D but demonstrated significantly lower uptake into and through the skin (30%). The findings confirm the unpredictable nature of excipients on delivery of actives with reference to skin even where there are minor differences in molecular structures. We also believe that they underline the ongoing necessity for fundamental studies on the interaction of topical excipients with the skin

The structural invisibility of outsiders: the role of migrant labour in the meat-processing industry

This article examines the role of migrant workers in meat-processing factories in the UK. Drawing on materials from mixed methods research in a number of case study towns across Wales, we explore the structural and spatial processes that position migrant workers as outsiders. While state policy and immigration controls are often presented as a way of protecting migrant workers from work-based exploitation and ensuring jobs for British workers, our research highlights that the situation ‘on the ground’ is more complex. We argue that ‘self-exploitation’ among the migrant workforce is linked to the strategies of employers and the organisation of work, and that hyper-flexible work patterns have reinforced the spatial and social invisibilities of migrant workers in this sector. While this creates problems for migrant workers, we conclude that it is beneficial to supermarkets looking to supply consumers with the regular supply of cheap food to which they have become accustomed

Liver test abnormalities in patients with HIV mono-infection : assessment with simple non-invasive fibrosis markers

BACKGROUND: Patients with HIV mono-infection may develop chronic liver disease due to a number of factors including hepatic steatosis. We estimated the prevalence and predictors of hepatic steatosis and fibrosis in a cohort of HIV-mono-infected patients with persistently deranged liver function tests. METHODS: Of 2398 consecutive patients at one UK clinical center, 156 (6.5%) had persistently abnormal transaminases in at least two measurements six months apart. We used APRI and FIB4 scores to determine the presence of significant and/or advanced fibrosis in this group as well as its potential associations. RESULTS: Mean age was 47.5\ub18.5 years and 91% (142/156) were males. Diabetes mellitus was present in 11% of patients; hypertension in 18%; and dyslipidemia in 52%. Almost all were on antiretroviral therapy (ART) (97%) and most were virologically suppressed (94%). Steatosis was detected by ultrasound in 71% of patients. The prevalence of FIB4 641.45, 1.46-3.24 and >3.25 was 67%, 29% and 4%, respectively, and that of APRI 640.5, 0.51-1.49 and >1.5 was 52%, 45% and 3% respectively. In multivariate analysis, only cumulative ART exposure was associated with FIB4>1.45 (odds ratio [OR] 1.008, 95% confidence interval [CI] 1.000-1.016), while APRI>0.5 was associated with higher alanine aminotransferase levels (OR 1.033, 95%CI 1.015-1.510). Twenty patients had a liver biopsy, of whom 13 had non-alcoholic fatty liver disease (NAFLD). CONCLUSIONS: Elevated transaminases are often present in HIV-mono-infected patients and this may be associated with NAFLD and/or ART. Non-invasive screening for the presence of NAFLD and fibrosis in all HIV-mono-infected patients as part of their routine clinical management should be further explore

Novelty and anxiolytic drugs dissociate two components of hippocampal theta in behaving rats

Hippocampal processing is strongly implicated in both spatial cognition and anxiety and is temporally organized by the theta rhythm. However, there has been little attempt to understand how each type of processing relates to the other in behaving animals, despite their common substrate. In freely moving rats, there is a broadly linear relationship between hippocampal theta frequency and running speed over the normal range of speeds used during foraging. A recent model predicts that spatial-translation-related and arousal/anxiety-related mechanisms of hippocampal theta generation underlie dissociable aspects of the theta frequency–running speed relationship (the slope and intercept, respectively). Here we provide the first confirmatory evidence: environmental novelty decreases slope, whereas anxiolytic drugs reduce intercept. Variation in slope predicted changes in spatial representation by CA1 place cells and novelty-responsive behavior. Variation in intercept predicted anxiety-like behavior. Our findings isolate and doubly dissociate two components of theta generation that operate in parallel in behaving animals and link them to anxiolytic drug action, novelty, and the metric for self-motion