371 research outputs found
Pneumocystis pneumonia in South African children diagnosed by molecular methods
Background: Pneumocystis pneumonia (PCP) is an important cause of hospitalization and mortality in HIV-infected children. However, the incidence of PCP has been underestimated due to poor sensitivity of diagnostic tests. The use of polymerase chain reaction (PCR) for pneumocystis has enabled more reliable diagnosis. This study describes the incidence, clinical features and outcome of PCP in South African children diagnosed using PCR. Methods: A prospective study of children hospitalised in South Africa with suspected PCP was done from November 2006 to August 2008. Clinical, laboratory and radiological information were collected. Lower respiratory tract specimens were obtained for PCP immunofluorescence (IF), real- time PCR for pneumocystis, bacterial and mycobacterial culture. Nasopharyngeal aspirates were taken for immunofluorescence (IF), real-time PCR for pneumocystis and PCR for respiratory viruses. A blood specimen for bacterial culture and for cytomegalovirus PCR was taken. Children were followed for the duration of their hospitalisation and the outcome was recorded. Results: 202 children [median (interquartile range, IQR) age 3.2 (2.1– 4.6) months] were enrolled; 124 (61.4%) were HIV infected. PCP was identified in 109 (54%) children using PCR, compared to 43 (21%) using IF and Grocott staining (p < 0.0001). Most PCP cases (88, 81%) occurred in HIV-infected children. All 21 cases (19%) occurring in HIV- negative children had another risk factor for PCP. On logistic regression, predictive factors for PCP were HIV infection, lack of fever, high respiratory rate and low oxygen saturation whilst cotrimoxazole prophylaxis was protective (OR 0.24; 95% CI 0.1 to 0.5; p < 0.002). The case fatality of children with PCP was higher than those without PCP (32.1% versus 17.2%; relative risk 1.87; 95% confidence interval (CI) 1.11 – 3.15). Amongst HIV-infected children, a CD4 less than 15% was the only independent predictor of mortality. Conclusions: The diagnostic yield for PCP is more than 2.5 times higher on PCR than other detection methods. PCP is a very common cause of severe hypoxic pneumonia and is associated with high mortality in HIV-infected African infants
Increasing the Effectiveness of Vaginal Microbicides: A Biophysical Framework to Rethink Behavioral Acceptability
Microbicide candidates delivered via gel vehicles are intended to coat the vaginal epithelium after application. The coating process depends on intrinsic biophysical properties of the gel texture, which restricts the potential choices for an effective product: the gel first must be physically synthesizable, then acceptable to the user, and finally applied in a manner promoting timely adequate coating, so that the user adherence is optimized. We present a conceptual framework anchoring microbicide behavioral acceptability within the fulfillment of the product biophysical requirements.We conducted a semi-qualitative/quantitative study targeting women aged 18-55 in Northern California to assess user preferences for microbicide gel attributes. Attributes included: (i) the wait time between application and intercourse, (ii) the gel texture and (iii) the trade-off between wait time and gel texture. Wait times were assessed using a mathematical model determining coating rates depending upon the gel's physical attributes.71 women participated. Results suggest that women would independently prefer a gel spreading rapidly, in 2 to 15 minutes (P<0.0001), as well as one that is thick or slippery (P<0.02). Clearly, thick gels do not spread rapidly; hence the motivation to study the trade-off. When asked the same question 'constrained' by the biophysical reality, women indicated no significant preference for a particular gel thickness (and therefore waiting time) (P>0.10) for use with a steady partner, a preference for a watery gel spreading rapidly rather than one having intermediate properties for use with a casual partner (P = 0.024).Biophysical constraints alter women's preferences regarding acceptable microbicide attributes. Product developers should offer a range of formulations in order to address all preferences. We designed a conceptual framework to rethink behavioral acceptability in terms of biophysical requirements that can help improve adherence in microbicide use ultimately enhancing microbicide effectiveness
Imaging of oil layers, curvature and contact angle in a mixed-wet and a water-wet carbonate rock
Evidence Against an Edge-On Disk Around the Extrasolar Planet 2MASS 1207 b and a New Thick Cloud Explanation for its Under-Luminosity
(Abridged) Since the discovery of the first directly-imaged, planetary-mass
object, 2MASS 1207 b, several works have sought to explain a disparity between
its observed temperature and luminosity. Given its known age, distance, and
spectral type, 2MASS 1207 b is under-luminous by a factor of ~10 (~2.5 mags)
when compared to standard models of brown-dwarf/giant-planet evolution. In this
paper, we study three possible sources of 2MASS 1207 b's under-luminosity.
First, we investigate Mohanty et al. (2007)'s hypothesis that a near edge-on
disk might be responsible for 2MASS 1207 b's under-luminosity. We conclude that
the hypothesis is unlikely due to the lack of variability seen in multi-epoch
photometry and unnecessary due to the increasing sample of under-luminous
brown-dwarfs/giant-exoplanets that cannot be explained by an edge-on disk.
Next, we test the analogous possibility that a spherical shell of dust, could
explain 2MASS 1207 b's under-luminosity. Models containing enough dust to
create ~2.5 mags of extinction, placed at reasonable radii, are ruled out by
our new Gemini/T-ReCS 8.7 micron photometric upper-limit for 2MASS 1207 b.
Finally, we investigate the possibility that 2MASS 1207 b is intrinsically
cooler than the commonly used AMES-DUSTY fits to its spectrum, and thus it is
not, in fact, under-luminous. New, thick cloud model grids by Madhusudhan et
al. (2011) fit 2MASS 1207 b's 1-10 micron SED well, but they do not quite fit
its near-infrared spectrum. However, we suggest that with some "tuning", they
might be capable of simultaneously reproducing 2MASS 1207 b's spectral shape
and luminosity. In this case, the whole class of young, under-luminous
brown-dwarfs/giant-exoplanets might be explained by atmospheres that are able
to suspend thick, dusty clouds in their photospheres at lower temperatures than
field brown-dwarfs.Comment: 35 pages, 9 figures, accepted to Ap
Interventional diagnostic procedure: A practical guide for the assessment of coronary vascular function
Approximately 40% of patients undergoing invasive coronary angiography for investigation of angina are found to have no obstructive coronary artery disease (ANOCA). Abnormal coronary function underlies coronary vasomotion syndromes including coronary endothelial dysfunction, microvascular angina, vasospastic angina, post-PCI angina and myocardial infarction with no obstructive coronary arteries (MINOCA). Each of these endotypes are distinct subgroups, characterized by specific disease mechanisms. Diagnostic criteria and linked therapy for these conditions are now established by expert consensus and clinical guidelines.
Coronary function tests are performed as an adjunctive interventional diagnostic procedure (IDP) in appropriately selected patients during coronary angiography. This aids differentiation of patients according to endotype. The IDP includes two distinct components: a diagnostic guidewire test and a pharmacological coronary reactivity test. The tests last approximately 5 minutes for the former and 10-15 minutes for the latter. Patient safety and staff education are key.
The diagnostic guidewire test measures parameters of coronary flow limitation (fractional flow reserve [FFR], coronary flow reserve [CFR], microvascular resistance [index of microvascular resistance (IMR)], basal resistance index, and vasodilator function [CFR, resistive reserve ratio (RRR)]).
The pharmacological coronary reactivity test measures the vasodilator potential and propensity to vasospasm of both the main coronary arteries and the micro-vessels. It involves intra-coronary infusion of acetylcholine and glyceryl trinitrate (GTN). Acetylcholine is not licensed for parenteral use and is therefore prescribed on a named-patient basis. Vasodilatation is the normal, expected response to infusion of physiological concentrations of acetylcholine. Vascular spasm represents an abnormal response, which supports the diagnosis of vasospastic angina.
The purpose of this practical guide is to provide information on the preparation and administration of the IDP in clinical practice. It discusses some key preparation and safety considerations, as well as tips for procedural success. The IDP supports stratified medicine for a personalized approach to health and wellbeing
Perspectives and impact of a parent-child intervention on dietary intake and physical activity behaviours, parental motivation, and parental body composition: A randomized controlled trial
Adults and children in Canada are not meeting physical activity guidelines nor consuming sufficient nutrient-rich foods. High engagement in these unhealthy behaviours can lead to obesity and its associated diseases. Parent-child interventions aimed at obesity prevention/treatment have assisted families with making positive changes to their nutrition and physical activity behaviours. Given that the home environment shapes early health behaviours, it is important to target both parents and children when addressing diet and physical activity. One method that has been shown to improve health outcomes is co-active coaching. The current study explored the impact of a threemonth co-active coaching and/or health education intervention on the dietary intake and physical activity behaviours of parents with overweight/obesity and their children (ages 2.5–10; of any weight). Body composition (i.e., body mass index [BMI] and waist circumference), changes in parental motivation with respect to physical activity and dietary behaviours, and parental perceptions of program improvements were collected. A concurrent mixed methods study comprised of a randomized controlled trial and a descriptive qualitative design was utilized. Fifty parent-child dyads were recruited and randomly assigned to the control (n = 25) or intervention (n = 25) group. Assessments were completed at baseline, mid-intervention (six weeks), postintervention (three months), and six-month follow-up. A linear mixed effects model was utilized for quantitative analysis. Inductive content analysis was used to extract themes from parent interviews. No significant results were observed over time for the dependent measures. Parents in both control and intervention groups reported varied program experiences, including developing changes in perspective, increased awareness of habits, and heightened accountability for making positive changes in themselves, and consequently, their families. Parents also shared barriers they faced when implementing changes (e.g., time, weather, stress). Qualitatively, both groups reported benefitting from this program, with the intervention group describing salient benefits from engaging in coaching. This research expands on the utility of coaching as a method for behaviour change, when compared to education only, in parents with overweight/obesity and their children
A population-based audit of surgical practice and outcomes of oncoplastic breast conservations in Scotland – an analysis of 589 patients
Introduction:
Current evidence for oncoplastic breast conservation (OBC) is based on single institutional series. Therefore, we carried out a population-based audit of OBC practice and outcomes in Scotland.
Methods:
A predefined database of patients treated with OBC was completed retrospectively in all breast units practicing OBC in Scotland.
Results:
589 patients were included from 11 units. Patients were diagnosed between September 2005 and March 2017. High volume units performed a mean of 19.3 OBCs per year vs. low volume units who did 11.1 (p = 0.012). 23 different surgical techniques were used. High volume units offered a wider range of techniques (8–14) than low volume units (3–6) (p = 0.004). OBC was carried out as a joint operation involving a breast and a plastic surgeon in 389 patients. Immediate contralateral symmetrisation rate was significantly higher when OBC was performed as a joint operation (70.7% vs. not joint operations: 29.8%; p < 0.001). The incomplete excision rate was 10.4% and was significantly higher after surgery for invasive lobular carcinoma (18.9%; p = 0.0292), but was significantly lower after neoadjuvant chemotherapy (3%; p = 0.031). 9.2% of patients developed major complications requiring hospital admission. Overall the complication rate was significantly lower after neoadjuvant chemotherapy (p = 0.035). The 5 year local recurrence rate was 2.7%, which was higher after OBC for DCIS (8.3%) than invasive ductal cancer (1.6%; p = 0.026). 5-year disease-free survival was 91.7%, overall survival was 93.8%, and cancer-specific survival was 96.1%.
Conclusion:
This study demonstrated that measured outcomes of OBC in a population-based multi-centre setting can be comparable to the outcomes of large volume single centre series
Temperature dependence on the mass susceptibility and mass magnetization of superparamagnetic Mn–Zn–ferrite nanoparticles as contrast agents for magnetic imaging of oil and gas reservoirs
The mass susceptibility (χmass) and mass magnetization (Mmass) were determined for a series of ternary manganese and zinc ferrite nanoparticles (Mn–Zn ferrite NPs, MnxZn1−xFe2O4) with different Mn:Zn ratios (0.08 ≤ x ≤ 4.67), prepared by the thermal decomposition reaction of the appropriate metal acetylacetonate complexes, and for the binary homologs (MxFe3−xO4, where M = Mn or Zn). Alteration of the Mn:Zn ratio in Mn–Zn ferrite NPs does not significantly affect the particle size. At room temperature and low applied field strength the mass susceptibility increases sharply as the Mn:Zn ratio increases, but above a ratio of 0.4 further increase in the amount of manganese results in the mass susceptibility decreasing slightly, reaching a plateau above Mn:Zn ≈ 2. The compositional dependence of the mass magnetization shows less of a variation at room temperature and high applied fields. The temperature dependence of the mass magnetization of Mn–Zn ferrite NPs is significantly less for Mn-rich compositions making them more suitable for downhole imaging at higher temperatures (>100 °C). For non-shale reservoirs, replacement of nMag by Mn-rich Mn–Zn ferrites will allow for significant signal-to-noise enhancement of 6.5× over NP magnetite
The Enigmatic Young Low-Mass Variable TWA 30
TWA 30 is a remarkable young (7+/-3 Myr), low-mass (0.12+/-0.04 Msun),
late-type star (M5+/-1) residing 42+/-2 pc away from the sun in the TW Hydrae
Association. It shows strong outflow spectral signatures such as [S II], [O I],
[O II], [O III], and Mg I], while exhibiting weak Halpha emission (-6.8+/-1.2
Angstroms). Emission lines of [S II] and [O I] are common to T Tauri stars
still residing in their natal molecular clouds, while [O III] and Mg I]
emission lines are incredibly rare in this same population; in the case of TWA
30, these latter lines may arise from new outflow material colliding into older
outflow fronts. The weak Halpha emission and small radial velocity shifts of
line emission relative to the stellar frame of rest (generally <=10 km/s)
suggest that the disk is viewed close to edge-on and that the stellar axis may
be inclined to the disk, similar to the AA Tau system, based on its temporal
changes in emission/absorption line strengths/profiles and variable reddening
(A_V=1.5-9.0). The strong Li absorption (0.61+/-0.13 Angstroms) and common
kinematics with members of the TWA confirm its age and membership to the
association. Given the properties of this system such as its proximity, low
mass, remarkable outflow signatures, variability, and edge-on configuration,
this system is a unique case study at a critical time in disk evolution and
planet-building processes.Comment: ApJ in press, 51 pages, 8 tables, 12 figures; converted to preprint
style since emulateapj version cut off Tables 4-
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