Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study.

BackgroundA feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI.MethodsIn this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed.ResultsThe results show that, in DCM mode and at (10-13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent.ConclusionsWe showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector's dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could be employed also for other low light levels applications, such as bioluminescence

Distribution of hepatitis B virus infection in Namibia

Background. Namibia regards hepatitis B virus (HBV) infection as a public health problem and introduced hepatitis B vaccinations for infants during 2009. However, information on HBV infection in the country remains limited, and effective public health interventions may be compromised in the absence of adequate evidence-based data. Available data from the World Health Organization (WHO) estimate that 15 - 60% of the normal population in many African countries may be positive for one or more of the HBV serological markers. Objective. To investigate the distribution of HBV infection in Namibia, using available laboratory data for 2013. Methods. A cross-sectional descriptive study was conducted using pre-existing electronic laboratory data on HBV infection. The data were retrieved from the central Namibia Institute of Pathology laboratory in Windhoek during January - December 2013. Tests were done on the following three main groups: (i) pregnant women during routine antenatal care (ANC) visits; (ii) patients with HIV/AIDS during antiretroviral therapy clinic visits; and (iii) any other individual suspected of having HBV infection. Results. Of a total of 77 238 hepatitis B surface antigen test results retrieved countrywide, 9 087 (11.8%) were positive. Of the positive results, 246/9 087 (2.7%) were in children aged 0 - 14 years, with the sexes equally affected. HBV infections increased markedly, particularly among females, in the age group 15 - 39 years, reaching a peak in the age group 30 - 34 years. Routine screening of pregnant women for HBV during ANC visits was found to be systematically conducted in only two regions, Ohangwena and Khomas. Conclusions. This study showed high proportions of positive results in pregnant women, patients with HIV/AIDS and individuals suspected of having HBV infection. The Ministry of Health and Social Services and stakeholders may wish to consider improving the routine and surveillance reporting systems for viral hepatitis and uptake of screening for pregnant women in all regions, and expanding HBV screening to other population groups. Population-based or similar studies are therefore required to determine the HBV prevalence and risk factors. This will assist Namibia in developing appropriate national viral hepatitis strategies as per WHO recommendations.S Afr Med J 2017;107(10):882-88

Australian midwives’ experiences of their workplace culture

© 2016 Australian College of Midwives Background A number of adverse events in Australia and overseas have highlighted the need to examine the workplace culture in the maternity environment. Little attention has been paid to the midwifery workplace culture in Australia. Aim The study aimed to explore the midwifery workplace culture from the perspective of midwives themselves. Methods A qualitative descriptive design was used. Group and individual interviews were undertaken of urban, regional and rural-based midwives in Australia. Data were analysed thematically. Findings The study showed that both new and experienced midwives felt frustrated by organisational environments and attitudes, and expressed strategies to cope with this. Five themes were identified from the data. These were: Bullying and resilience, Fatigued and powerless midwives, Being ‘hampered by the environment’, and The importance of support for midwifery. Discussion The study discusses the themes in depth. In particular, discussion focusses on how midwifery practise was affected by midwives’ workplace culture and model of care, and the importance of supportive relationships from peers and managers. Conclusion This study illuminated both positive and negative aspects of the midwifery workplace culture in Australia. One way to ensure the wellbeing and satisfaction of midwives in order to maintain the midwifery workforce and provide quality care to women and their families is to provide positive workplace cultures

Creating clinical pharmacy capacity in Namibia: a collaboration to establish a post-graduate pharmacy degree programme

Namibia has previously relied on external training of pharmacists but began in-country training in 2011. In response to an identified need for postgraduate clinical pharmacy development and training in the country, a Master’s degree was set up at the University of Namibia in 2016. The country has a considerable health burden of HIV and TB as well as a shortage of healthcare professionals. A UK clinical diploma model was adapted to meet the specific needs of the country and wider region, ensuring students could access the course over a sparsely populated, but large geographical spread, in addition to providing work-based learning, embedding research skills for future development, and focusing on the health needs of Namibia. The course uses online learning platforms and contact sessions to cover both knowledge and skill acquisition throughout the 3 years of the course. UK and US clinical pharmacists are utilised to provide specialist input, both remotely and within student workplaces, and further support has come from collaborations, including cross-site visits, with the UK-based pharmacy school whose diploma model was adapted. Challenges have included a shortage of clinical mentors, also compounding the students’ difficulty in visualising their future roles, as well as lone practitioners finding it hard to attend all contact sessions. The initial dropout rates of earlier cohorts have since reduced with greater understanding of the programme, and enthusiasm for the course remains high. The aim for the Master’s is to train students to become competent clinical pharmacists, thus having the knowledge and skills to mentor future cohorts of the course, as well as expanding the specialty within the country

Spatially and genetically distinct African trypanosome virulence variants defined by host interferon-g response

We describe 2 spatially distinct foci of human African trypansomiasis in eastern Uganda. The Tororo and Soroti foci of <i>Trypanosoma brucei rhodesiense</i> infection were genetically distinct as characterized by 6 microsatellite and 1 minisatellite polymorphic markers and were characterized by differences in disease progression and host-immune response. In particular, infections with the Tororo genotype exhibited an increased frequency of progression to and severity of the meningoencephalitic stage and higher plasma interferon (IFN)–γ concentration, compared with those with the Soroti genotype. We propose that the magnitude of the systemic IFN-γ response determines the time at which infected individuals develop central nervous system infection and that this is consistent with the recently described role of IFN-γ in facilitating blood-brain barrier transmigration of trypanosomes in an experimental model of infection. The identification of trypanosome isolates with differing disease progression phenotypes provides the first field-based genetic evidence for virulence variants in T. <i>brucei rhodesiense</i>

A disk of dust and molecular gas around a high-mass protostar

The processes leading to the birth of low-mass stars such as our Sun have been well studied, but the formation of high-mass (> 8 x Sun's mass) stars has heretofore remained poorly understood. Recent observational studies suggest that high-mass stars may form in essentially the same way as low-mass stars, namely via an accretion process, instead of via merging of several low-mass (< 8 Msun) stars. However, there is as yet no conclusive evidence. Here, we report the discovery of a flattened disk-like structure observed at submillimeter wavelengths, centered on a massive 15 Msun protostar in the Cepheus-A region. The disk, with a radius of about 330 astronomical units (AU) and a mass of 1 to 8 Msun, is detected in dust continuum as well as in molecular line emission. Its perpendicular orientation to, and spatial coincidence with the central embedded powerful bipolar radio jet, provides the best evidence yet that massive stars form via disk accretion in direct analogy to the formation of low-mass stars

Adolescent diet and risk of breast cancer

BACKGROUND: Early life exposures, including diet, have been implicated in the etiology of breast cancer. METHODS: A nested case-control study was conducted among participants in the Nurses' Health Study who completed a 24-item questionnaire about diet during high school. There were 843 eligible cases diagnosed between onset of study (1976) and before the return of the high school diet questionnaire (1986), who were matched 10:1 with controls on the basis of age. RESULTS: Women who had, during adolescence, a higher consumption of eggs, vegetable fat and fiber had a lower risk of breast cancer, whereas risk of breast cancer was increased among women who consumed more butter. CONCLUSIONS: A possible association of elements of adolescent diet with risk of breast cancer is reported, but the findings require confirmation in prospective study

Exponential Random Graph Modeling for Complex Brain Networks

Exponential random graph models (ERGMs), also known as p* models, have been utilized extensively in the social science literature to study complex networks and how their global structure depends on underlying structural components. However, the literature on their use in biological networks (especially brain networks) has remained sparse. Descriptive models based on a specific feature of the graph (clustering coefficient, degree distribution, etc.) have dominated connectivity research in neuroscience. Corresponding generative models have been developed to reproduce one of these features. However, the complexity inherent in whole-brain network data necessitates the development and use of tools that allow the systematic exploration of several features simultaneously and how they interact to form the global network architecture. ERGMs provide a statistically principled approach to the assessment of how a set of interacting local brain network features gives rise to the global structure. We illustrate the utility of ERGMs for modeling, analyzing, and simulating complex whole-brain networks with network data from normal subjects. We also provide a foundation for the selection of important local features through the implementation and assessment of three selection approaches: a traditional p-value based backward selection approach, an information criterion approach (AIC), and a graphical goodness of fit (GOF) approach. The graphical GOF approach serves as the best method given the scientific interest in being able to capture and reproduce the structure of fitted brain networks

Functional strength training versus movement performance therapy for upper limb motor recovery early after stroke: a RCT

BACKGROUND: Not all stroke survivors respond to the same form of physical therapy in the same way early after stroke. The response is variable and a detailed understanding of the interaction between specific physical therapies and neural structure and function is needed. OBJECTIVES: To determine if upper limb recovery is enhanced more by functional strength training (FST) than by movement performance therapy (MPT), to identify the differences in the neural correlates of response to (1) FST and (2) MPT and to determine whether or not pretreatment neural characteristics can predict recovery in response to (1) FST and (2) MPT. DESIGN: Randomised, controlled, observer-blind, multicentre trial with embedded explanatory investigations. An independent facility used computer-generated randomisation for participants’ group allocation. SETTING: In-patient rehabilitation, participants’ homes, university movement analysis facilities and NHS or university neuroimaging departments in the UK. PARTICIPANTS: People who were between 2 and 60 days after stroke in the territory of the anterior cerebral circulation, with some voluntary muscle contraction in the more affected upper limb but not full function. INTERVENTIONS: Routine rehabilitation [conventional physical therapy (CPT)] plus either MPT or FST in equal doses during a 6-week intervention phase. FST was progressive resistive exercise provided during training of functional tasks. MPT was therapist ‘hands-on’ sensory input and guidance for production of smooth and accurate movement. MAIN OUTCOMES: Action Research Arm Test (ARAT) score for clinical efficacy. Neural measures were made of corticocortical [fractional anisotropy (FA) from corpus callosum midline], corticospinal connectivity (asymmetry of corticospinal tracts FA) and resting motor threshold of paretic biceps brachii (pBB) and extensor carpi radialis muscles (derived from transcranial magnetic stimulation). ANALYSIS: Change in ARAT scores were analysed using analysis of covariance models adjusted for baseline variables and randomisation strata. Correlation coefficients were calculated between change in neural measures and change in ARAT score per group and for the whole sample. An interaction term was calculated for each baseline neural measure and ARAT score change from baseline to outcome. RESULTS: A total of 288 participants were randomised [mean age 72.2 (standard deviation 12.5) years; mean ARAT score of 25.5 (18.2); n = 283]. For the 240 participants with ARAT measurements at baseline and outcome, the mean change scores were FST + CPT = 9.70 (11.72) and MPT + CPT = 7.90 (9.18). The group difference did not reach statistical significance (least squares mean difference 1.35, 95% confidence interval –1.20 to 3.90; p = 0.298). Correlations between ARAT change scores and baseline neural values ranged from –0.147 (p = 0.385) for whole-sample corticospinal connectivity (n = 37) to 0.199 (p = 0.320) for MPT + CPT resting motor threshold pBB (n = 27). No statistically significant interaction effects were found between baseline neural variables and change in ARAT score. There were no differences between groups in adverse events. LIMITATIONS: The number of participants in the embedded explanatory investigation was lower than expected. CONCLUSIONS: The small difference in upper limb improvement in response to FST and MPT did not reach statistical significance. Baseline neural measures neither correlated with upper limb recovery nor predicted therapy response. FUTURE WORK: Needs to continue investigation of the variability of response to specific physical therapies in people early after stroke. TRIAL REGISTRATION: Current Controlled Trials ISRCTN19090862 and National Research Ethics Service reference number 11/EE/0524. FUNDING: This project was funded by the Efficacy and Mechanism Evaluation programme, a Medical Research Council and National Institute for Health Research partnership