Multimodal probes : superresolution and transmission electron microscopy imaging of mitochondria, and oxygen mapping of cells, using small-molecule Ir(III) luminescent complexes

We describe an Ir(III)-based small-molecule, multimodal probe for use in both light and electron microscopy. The direct correlation of data between light- and electron-microscopy-based imaging to investigate cellular processes at the ultrastructure level is a current challenge, requiring both dyes that must be brightly emissive for luminescence imaging and scatter electrons to give contrast for electron microscopy, at a single working concentration suitable for both methods. Here we describe the use of Ir(III) complexes as probes that provide excellent image contrast and quality for both luminescence and electron microscopy imaging, at the same working concentration. Significant contrast enhancement of cellular mitochondria was observed in transmission electron microscopy imaging, with and without the use of typical contrast agents. The specificity for cellular mitochondria was also confirmed with MitoTracker using confocal and 3D-structured illumination microscopy. These phosphorescent dyes are part of a very exclusive group of transition-metal complexes that enable imaging beyond the diffraction limit. Triplet excited-state phosphorescence was also utilized to probe the O2 concentration at the mitochondria in vitro, using lifetime mapping techniques

Prevalence of prehypertension and its relationship to risk factors for cardiovascular disease in Jamaica: Analysis from a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>Recent studies have documented an increased risk of cardiovascular disease (CVD) in persons with systolic blood pressures of 120–139 mmHg and/or diastolic blood pressures of 80–89 mmHg, classified as prehypertension in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. In this paper we estimate the prevalence of prehypertension in Jamaica and evaluate the relationship between prehypertension and other risk factors for CVD.</p> <p>Methods</p> <p>The study used data from participants in the Jamaica Lifestyle Survey conducted from 2000–2001. A sample of 2012 persons, 15–74 years old, completed an interviewer administered questionnaire and had anthropometric and blood pressure measurements performed by trained observers using standardized procedures. Fasting glucose and total cholesterol were measured using a capillary blood sample. Analysis yielded crude, and sex-specific prevalence estimates for prehypertension and other CVD risk factors. Odds ratios for associations of prehypertension with CVD risk factors were obtained using logistic regression.</p> <p>Results</p> <p>The prevalence of prehypertension among Jamaicans was 30% (95% confidence interval [CI] 27%–33%). Prehypertension was more common in males, 35% (CI 31%–39%), than females, 25% (CI 22%–28%). Almost 46% of participants were overweight; 19.7% were obese; 14.6% had hypercholesterolemia; 7.2% had diabetes mellitus and 17.8% smoked cigarettes. With the exception of cigarette smoking and low physical activity, all the CVD risk factors had significantly higher prevalence in the prehypertensive and hypertensive groups (p for trend < 0.001) compared to the normotensive group. Odds of obesity, overweight, high cholesterol and increased waist circumference were significantly higher among younger prehypertensive participants (15–44 years-old) when compared to normotensive young participants, but not among those 45–74 years-old. Among men, being prehypertensive increased the odds of having >/=3 CVD risk factors versus no risk factors almost three-fold (odds ratio [OR] 2.8 [CI 1.1–7.2]) while among women the odds of >/=3 CVD risk factors was increased two-fold (OR 2.0 [CI 1.3–3.8])</p> <p>Conclusion</p> <p>Prehypertension occurs in 30% of Jamaicans and is associated with increased prevalence of other CVD risk factors. Health-care providers should recognize the increased CVD risk of prehypertension and should seek to identify and treat modifiable risk factors in these persons.</p

Modeling FETCH Observations of 2005 May 13 CME

This paper evaluates the quality of CME analysis that has been undertaken with the rare Faraday rotation observation of an eruption. Exploring the capability of the FETCH instrument hosted on the MOST mission, a four-satellite Faraday rotation radio sounding instrument deployed between the Earth and the Sun, we discuss the opportunities and challenges to improving the current analysis approaches.Comment: 33 pages, 24 figure

A biophysical model of prokaryotic diversity in geothermal hot springs

Recent field investigations of photosynthetic bacteria living in geothermal hot spring environments have revealed surprisingly complex ecosystems, with an unexpected level of genetic diversity. One case of particular interest involves the distribution along hot spring thermal gradients of genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis. In such systems, a single variable, temperature, defines the relevant environmental variation. In spite of this, each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than the expected single thermal strain adapted to the local environmental temperature. Here we analyze microbiology data from several ecological studies to show that the thermal distribution field data exhibit several universal features independent of location and specific bacterial strain. These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature. Further, we present a simple population dynamics model of these systems that is highly constrained by biophysical data and by physical features of the environment. This model can explain in detail the observed diversity of different strains of the photosynthetic bacteria. It also reproduces the observed thermal population distributions, as well as certain features of population dynamics observed in laboratory studies of the same organisms

Diurnal and Seasonal Variations in Chlorophyll Fluorescence Associated with Photosynthesis at Leaf and Canopy Scales

There is a critical need for sensitive remote sensing approaches to monitor the parameters governing photosynthesis, at the temporal scales relevant to their natural dynamics. The photochemical reflectance index (PRI) and chlorophyll fluorescence (F) offer a strong potential for monitoring photosynthesis at local, regional, and global scales, however the relationships between photosynthesis and solar induced F (SIF) on diurnal and seasonal scales are not fully understood. This study examines how the fine spatial and temporal scale SIF observations relate to leaf level chlorophyll fluorescence metrics (i.e., PSII yield, YII and electron transport rate, ETR), canopy gross primary productivity (GPP), and PRI. The results contribute to enhancing the understanding of how SIF can be used to monitor canopy photosynthesis. This effort captured the seasonal and diurnal variation in GPP, reflectance, F, and SIF in the O2A (SIFA) and O2B (SIFB) atmospheric bands for corn (Zea mays L.) at a study site in Greenbelt, MD. Positive linear relationships of SIF to canopy GPP and to leaf ETR were documented, corroborating published reports. Our findings demonstrate that canopy SIF metrics are able to capture the dynamics in photosynthesis at both leaf and canopy levels, and show that the relationship between GPP and SIF metrics differs depending on the light conditions (i.e., above or below saturation level for photosynthesis). The sum of SIFA and SIFB (SIFA+B), as well as the SIFA+B yield, captured the dynamics in GPP and light use efficiency, suggesting the importance of including SIFB in monitoring photosynthetic function. Further efforts are required to determine if these findings will scale successfully to airborne and satellite levels, and to document the effects of data uncertainties on the scaling

Assessing dysphagia via telerehabilitation: patient perceptions and satisfaction

To gain insight into factors which may infl uence future acceptance of dysphagia management via telerehabilitation, patients’ perceptions were examined before and after a telerehabilitation assessment session. Forty adult patients with dysphagia(M = 66 years, SD = 16.25) completed pre- and post-session questionnaires which consisted of 14 matched questions worded to suit pre- and post-conditions. Questions explored comfort with the use of telerehabilitation, satisfaction with audio and video quality, benefi ts of telerehabilitation assessments and patients’ preferred assessment modality. Questions were rated on a 5-point scale (1 = strongly disagree, 3 = unsure, 5 = strongly agree). Patients’ comfort with assessment via telerehabilitation was high in over 80% of the group both pre- and post-assessment. Pre-assessment, patients were unsure what to expect with the auditory and visual aspects of the videoconference, however there were signifi cant positive changes reported post-experience. In relation to perceived benefits of telerehabilitation services in general, most patients believed in the value of telerehabilitation and post-assessment this increased to 90 – 100% agreement. Although 92% felt they would be comfortable receiving services via telerehabilitation, 45% of patients indicated ultimate preference for a traditional faceto-face assessment. The data highlight that patients are interested in and willing to receive services via telerehabilitation; however, any concerns should be addressed pre-assessment

Periodic Active Case Finding for TB: When to Look?

OBJECTIVE: To investigate the factors influencing the performance and cost-efficacy of periodic rounds of active case finding (ACF) for TB. METHODS: A mathematical model of TB dynamics and periodic ACF (PACF) in the HIV era, simplified by assuming constant prevalence of latent TB infection, is analyzed for features that control intervention outcome, measured as cases averted and cases found. Explanatory variables include baseline TB incidence, interval between PACF rounds, and different routine and PACF case-detection rates among HIV-infected and uninfected TB cases. FINDINGS: PACF can be cost-saving over a 10 year time frame if the cost-per-round is lower than a threshold proportional to initial incidence and cost-per-case-treated. More cases are averted at higher baseline incidence rates, when more potent PACF strategies are used, intervals between PACF rounds are shorter, and when the ratio of HIV-negative to positive TB cases detected is higher. More costly approaches, e.g. radiographic screening, can be as cost-effective as less costly alternatives if PACF case-detection is higher and/or implementation less frequent. CONCLUSION: Periodic ACF can both improve control and save medium-term health care costs in high TB burden settings. Greater costs of highly effective PACF at frequent (e.g. yearly) intervals may be offset by higher numbers of cases averted in populations with high baseline TB incidence, higher prevalence of HIV-uninfected cases, higher costs per-case-treated, and more effective routine case-detection. Less intensive approaches may still be cost-neutral or cost-saving in populations lacking one or more of these key determinants

A sibling study of whether maternal exposure to different types of natural space is related to birth weight

Background: Birthweight is an important determinant of health across the life course. Maternal exposure to natural space has been linked to higher birthweight, but stronger evidence of a causal link is needed. We use a quasi-experimental sibling study design to investigate if change in the mother’s exposure to natural space between births was related to birthweight, in urban Scotland. Methods: Amount (% area) of total natural space, total accessible (public) natural space, parks, woodlands and open water within 100 m of the mother’s postcode was calculated for eligible births (n = 40 194; 1991–2010) in the Scottish Longitudinal Study (a semi-random 5.3% sample of the Scottish population). Associations between natural space and birthweight were estimated, using ordinary least squares and fixed effects models. Results: Birthweight was associated with the total amount of natural space around the mother’s home (+8.2 g for interquartile range increase), but was unrelated to specific types of natural space. This whole-sample relationship disappeared in the sibling analysis, indicating residual confounding. The sibling models showed effects for total natural space with births to women who already had children (+20.1 g), and to those with an intermediate level of education (+14.1 g). Conclusions: The importance of total natural space for birthweight suggests that benefits can be experienced near to as well as within natural space. Ensuring expectant mothers have good access to high quality neighbourhood natural space has the potential to improve the infant’s start in life, and consequently their health trajectory over the life course