Ozone depletion events observed in the high latitude surface layer during the TOPSE aircraft program

During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58° between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as Baffin Bay and Hudson Bay and as late as 22 May. There is good evidence that these more southern events did not form in situ but were the result of export of ozone‐depleted air from the surface layer of the Arctic Ocean. Surprisingly, relatively intact transport of ODEs occurred over distances of 900–2000 km and in some cases over rough terrain. Accumulation of constituents in the frozen surface over the dark winter period cannot be a strong prerequisite of ozone depletion since latitudes south of the Arctic Ocean would also experience a long dark period. Some process unique to the Arctic Ocean surface or its coastal regions remains unidentified for the release of ozone‐depleting halogens. There was no correspondence between coarse surface features such as solid ice/snow, open leads, or polynyas with the occurrence of or intensity of ozone depletion over the Arctic or subarctic regions. Depletion events also occurred in the absence of long‐range transport of relatively fresh “pollution” within the high latitude surface layer, at least in spring 2000. Direct measurements of halogen radicals were not made. However, the flights do provide detailed information on the vertical structure of the surface layer and, during the constant 30 m altitude legs, measurements of a variety of constituents including hydroxyl and peroxy radicals. A summary of the behavior of these constituents is made. The measurements were consistent with a source of formaldehyde from the snow/ice surface. Median NOx in the surface layer was 15 pptv or less, suggesting that surface emissions were substantially converted to reservoir constituents by 30 m altitude and that ozone production rates were small (0.15–1.5 ppbv/d) at this altitude. Peroxyacetylnitrate (PAN) was by far the major constituent of NOy in the surface layer independent of the ozone mixing ratio

Frailty in primary care: a review of its conceptualization and implications for practice

Frail, older patients pose a challenge to the primary care physician who may often feel overwhelmed by their complex presentation and tenuous health status. At the same time, family physicians are ideally suited to incorporate the concept of frailty into their practice. They have the propensity and skill set that lends itself to patient-centred care, taking into account the individual subtleties of the patient's health within their social context. Tools to identify frailty in the primary care setting are still in the preliminary stages of development. Even so, some practical measures can be taken to recognize frailty in clinical practice and begin to address how its recognition may impact clinical care. This review seeks to address how frailty is recognised and managed, especially in the realm of primary care

The psychometric properties of three self-report screening instruments for identifying frail older people in the community

Background: Frailty is highly prevalent in older people. Its serious adverse consequences, such as disability, are considered to be a public health problem. Therefore, disability prevention in community-dwelling frail older people is considered to be a priority for research and clinical practice in geriatric care. With regard to disability prevention, valid screening instruments are needed to identify frail older people in time. The aim of this study was to evaluate and compare the psychometric properties of three screening instruments: the Groningen Frailty Indicator (GFI), the Tilburg Frailty Indicator (TFI) and the Sherbrooke Postal Questionnaire (SPQ). For validation purposes the Groningen Activity Restriction Scale (GARS) was added. Methods: A questionnaire was sent to 687 community-dwelling older people (>= 70 years). Agreement between instruments, internal consistency, and construct validity of instruments were evaluated and compared. Results: The response rate was 77%. Prevalence estimates of frailty ranged from 40% to 59%. The highest agreement was found between the GFI and the TFI (Cohen's kappa = 0.74). Cronbach's alpha for the GFI, the TFI and the SPQ was 0.73, 0.79 and 0.26, respectively. Scores on the three instruments correlated significantly with each other (GFI - TFI, r = 0.87; GFI - SPQ, r = 0.47; TFI - SPQ, r = 0.42) and with the GARS (GFI - GARS, r = 0.57; TFI - GARS, r = 0.61; SPQ - GARS, r = 0.46). The GFI and the TFI scores were, as expected, significantly related to age, sex, education and income. Conclusions: The GFI and the TFI showed high internal consistency and construct validity in contrast to the SPQ. Based on these findings it is not yet possible to conclude whether the GFI or the TFI should be preferred; data on the predictive values of both instruments are needed. The SPQ seems less appropriate for postal screening of frailty among community-dwelling older peopl

Infrared light excites cells by changing their electrical capacitance

Optical stimulation has enabled important advances in the study of brain function and other biological processes, and holds promise for medical applications ranging from hearing restoration to cardiac pace making. In particular, pulsed laser stimulation using infrared wavelengths >1.5 μm has therapeutic potential based on its ability to directly stimulate nerves and muscles without any genetic or chemical pre-treatment. However, the mechanism of infrared stimulation has been a mystery, hindering its path to the clinic. Here we show that infrared light excites cells through a novel, highly general electrostatic mechanism. Infrared pulses are absorbed by water, producing a rapid local increase in temperature. This heating reversibly alters the electrical capacitance of the plasma membrane, depolarizing the target cell. This mechanism is fully reversible and requires only the most basic properties of cell membranes. Our findings underscore the generality of pulsed infrared stimulation and its medical potential

DNA methylation and the epigenetic clock in relation to physical frailty in older people:The Lothian Birth Cohort 1936

Background: The biological mechanisms underlying frailty in older people are poorly understood. There is some evidence to suggest that DNA methylation patterns may be altered in frail individuals. Methods: Participants were 791 people aged 70 years from the Lothian Birth Cohort 1936. DNA methylation was measured in whole blood. Biological age was estimated using two measures of DNA methylation-based age acceleration - extrinsic and intrinsic epigenetic age acceleration. We carried out an epigenome-wide association study of physical frailty, as defined by the Fried phenotype. Multinomial logistic regression was used to calculate relative risk ratios for being physically frail or pre-frail according to epigenetic age acceleration. Results: There was a single significant (P=1.16x10-7) association in the epigenome-wide association study comparing frail versus not frail. The same CpG was not significant when comparing pre-frail versus not frail. Greater extrinsic epigenetic age acceleration was associated with an increased risk of being physically frail, but not of being pre-frail. For a year increase in extrinsic epigenetic age acceleration, age- and sex-adjusted relative risk ratios (95% CI) for being physically frail or pre-frail were 1.06 (1.02, 1.10) and 1.02 (1.00, 1.04) respectively. After further adjustment for smoking and chronic disease, the association with physical frailty remained significant. Intrinsic epigenetic age acceleration was not associated with physical frailty status.Conclusions: People who are biologically older, as indexed by greater extrinsic epigenetic age acceleration, are more likely to be physically frail. Future research will need to investigate whether epigenetic age acceleration plays a causal role in the onset of physical frailty

Metabolic Profiling of an Echinostoma caproni Infection in the Mouse for Biomarker Discovery

Consumption of raw fish and other freshwater products can lead to unpleasant worm infections. Indeed, such worm infections are of growing public health and veterinary concern, but they are often neglected, partially explained by the difficulty of accurate diagnosis. In the present study we infected 12 mice with an intestinal worm (i.e., Echinostoma caproni) and collected blood, stool, and urine samples 7 times between 1 and 33 days after the infection. At the same time points, blood, stool, and urine were also sampled from 12 uninfected mice. These biofluid samples were examined with a spectrometer and data were analyzed with a multivariate approach. We observed important differences between the infected and the uninfected control animals. For example, we found an increased level of branched chain amino acids in the stool of infected mice and subsequent depletion in blood plasma. Additionally, we observed changes related to a disturbed intestinal bacterial composition, particularly in urine and stool. The combination of results from the three types of biofluids gave the most comprehensive characterization of an E. caproni infection in the mouse. Urine would be the biofluid of choice for diagnosis of an infection because the ease of sample collection and the high number and extent of changed metabolites

Developmental consequences of perinatal cannabis exposure: behavioral and neuroendocrine effects in adult rodents

Cannabis is the most commonly used illicit drug among pregnant women. Since the endocannabinoid system plays a crucial role in brain development, maternal exposure to cannabis derivatives might result in long-lasting neurobehavioral abnormalities in the exposed offspring. It is difficult to detect these effects, and their underlying neurobiological mechanisms, in clinical cohorts, because of their intrinsic methodological and interpretative issues. The present paper reviews relevant rodent studies examining the long-term behavioral consequences of exposure to cannabinoid compounds during pregnancy and/or lactation. Maternal exposure to even low doses of cannabinoid compounds results in atypical locomotor activity, cognitive impairments, altered emotional behavior, and enhanced sensitivity to drugs of abuse in the adult rodent offspring. Some of the observed behavioral abnormalities might be related to alterations in stress hormone levels induced by maternal cannabis exposure. There is increasing evidence from animal studies showing that cannabinoid drugs are neuroteratogens which induce enduring neurobehavioral abnormalities in the exposed offspring. Several preclinical findings reviewed in this paper are in line with clinical studies reporting hyperactivity, cognitive impairments and altered emotionality in humans exposed in utero to cannabis. Conversely, genetic, environmental and social factors could also influence the neurobiological effects of early cannabis exposure in humans