A lightweight near-infrared spectrometer for the detection of trace atmospheric species

This paper describes the development and deployment of a lightweight in situ near-infrared tunable diode laser absorption spectrometer (TDLAS) for balloon-borne measurements of trace species such as methane in the upper troposphere and stratosphere. The key feature of the instrument design is its ability to provide high sensitivity measurements with better than 1 part in 10(6) Hz(-1/2) optical sensitivity in a lightweight package weighing as little as 6 kg, and maintaining this level of performance over the wide range of conditions experienced during field measurements. The absolute accuracy for methane measurements is approximately 10% limited by uncertainties in determining the gas temperature in the measurement volume. The high sensitivity and high temporal resolution (2.3 s measurement period) enables details of the fine-scale structure in the atmosphere to be measured. The TDLAS instrument has been used on a number of major international measurement campaigns. Intercomparison with other instruments during these campaigns have confirmed the comparability of the results from this instrument with measurements made by a range of other techniques, and demonstrated the instruments suitability for studies of atmospheric dynamics, transport, and mixing processes.

First national survey of Mycobacterium tuberculosis drug resistance, Madagascar, 2005-2006

SETTING

A national survey of Mycobacterium tuberculosis resistance was conducted for the first time in Madagascar between October 2005 and July 2007.

OBJECTIVE

To determine resistance rates among new and previously treated cases of pulmonary tuberculosis.

METHODS

In a cluster sampling representative of the general population of the country, 1275 smear-positive tuberculosis patients recruited at 34 sites, 926 new patients and 87 previously treated patients underwent drug susceptibility testing against rifampicin (RMP), isoniazid (INH), streptomycin and ethambutol on Löwenstein-Jensen medium using the indirect proportion method.

RESULTS

Resistance among new cases was 6.5% (95%CI 4.9-8) and among previously treated cases it was 11.5% (95%CI 4.8-18.2). Monoresistance among new cases was 5.8% (95%CI 4.2-7.3), mainly to INH (3.7%). Multiresistance to INH and RMP was 0.2% (95%CI 0-0.5) among new cases and 3.4% (95%CI 0-7.2) among previously treated cases. No significant difference was noted with regard to sex or age.

CONCLUSION

The rates of resistance among new and previously treated cases remain relatively low in Madagascar.

Changes in ectomycorrhizal community structure on two containerized oak hosts across an experimental hydrologic gradient

Shifts in ectomycorrhizal (ECM) community structure were examined across an experimental hydrologic gradient on containerized seedlings of two oak species, Quercus montana and Quercus palustris, inoculated from a homogenate of roots from mature oak trees. At the end of one growing season, seedlings were harvested, roots were sorted by morphotype, and proportional colonization of each type was determined. DNA was subsequently extracted from individual root tips for polymerase chain reaction, restriction fragment length polymorphism, and rDNA sequencing of the ITS1/5.8S/ITS2 region to determine identities of fungal morphotypes. Twelve distinct molecular types were identified. Analysis of similarity showed that ECM fungal assemblages shifted significantly in composition across the soil moisture gradient. Taxa within the genus Tuber and the family Thelephoraceae were largely responsible for the changes in fungal assemblages. There were also significant differences in ECM community assemblages between the two oak host species. These results demonstrate that the structure of ECM fungal communities depends on both the abiotic and biotic environments and can shift with changes in soil moisture as well as host plant, even within the same genus.

Efficacy of antiglaucoma fixed combination therapy versus unfixed components in reducing intraocular pressure: a systematic review

AIM

To evaluate the efficacy of the fixed combination ocular hypotensive therapies compared with their non-fixed components used concomitantly for lowering intraocular pressure (IOP) in glaucoma and ocular hypertension.

METHODS

A systematic review of the literature, up to May 2007, without limits on year or language of publication was performed. Seven randomised controlled trials (n = 2,083 eyes) were identified. Assessment of methodological quality was made using standardised criteria. Results were pooled quantitatively using meta-analysis methods, and statistical analysis was performed using STATA software. The difference in mean intraocular pressure (mm Hg) from baseline between the fixed combination and non-fixed component therapies was compared. Non-inferiority in terms of efficacy was set at an upper confidence limit of < or =1.5 mm Hg for all time points (hour (Hr)0, Hr2 and Hr8) and evaluated at 12 weeks. Safety was evaluated from data on adverse events as reported in the included studies.

RESULTS

Of the 679 abstracts identified, seven randomised controlled trials met the selection criteria. The quality scores of included studies were high (mean of 29.4, maximum score 30). The mean differences (95% CI) and p values at 12 weeks were as follows: 0.200 mm Hg, (CI -0.106 to 0.507), p = 0.20 for Hr0, 0.393 mm Hg (CI 0.038 to 0.747), p = 0.03 for Hr2 and 0.501 mm Hg (CI 0.156 to 0.846), p = 0.004 for Hr8. Although both Hr2 and Hr8 showed statistical significance favouring the non-fixed combinations, the non-inferiority measure < or =1.5 mm Hg upper confidence limit was not exceeded.

CONCLUSIONS

Fixed combination therapies are equally safe and effective at lowering IOP as their non-fixed components administered concomitantly.

Clinical trial: oral prednisolone metasulfobenzoate (Predocol) vs. oral prednisolone for active ulcerative colitis

BACKGROUND

Systemic corticosteroids are effective in ulcerative colitis but commonly cause side effects.

AIM

To compare the safety and efficacy of a sparingly absorbed formulation of prednisolone metasulfobenzoate (Predocol) with a conventional tapering course of oral prednisolone.

METHOD

In a double-blind randomized study, 59 active ulcerative colitis patients received Predocol 40 mg/day for 6 months, 61 received Predocol 60 mg/day for 6 months and 61 received prednisolone 40 mg/day for 2 weeks, tapered to week 8, followed by placebo until 6 months.

RESULTS

Steroid-related side effects assessed using a 10-cm visual analogue scale were fewer at 2 months with Predocol 40 mg [VAS 8.1 cm (2.6), mean (s.d.)], or 60 mg [8.1 (2.1)] compared with prednisolone [6.7 (2.7); P = 0.01]. Mood changes affected 43% receiving prednisolone at 4 weeks vs. 8% for Predocol 40 mg (P = 0.001). Remission rates (Powell-Tuck < or =2) at 2 months were Predocol 40 mg 46%, Predocol 60 mg 28% and tapering prednisolone 41% (P = 0.13). Visual analogue scale for efficacy also showed non-inferiority for Predocol 40 mg/day. Remission rates at 6 months were Predocol 40 mg 51%, Predocol 60 mg 38% and tapering prednisolone 32% (P = 0.08).

CONCLUSION

Predocol 40 mg/day has similar efficacy but markedly fewer side effects than a conventional tapering prednisolone regimen (ISRCTN14133410).

Effects of cartilage rings on airflow and particle deposition in the trachea and main bronchi

In most computational fluid dynamic (CFD) analysis of the human lung, it has been assumed that the trachea and branches of the lung have smooth walls. In order to determine if this is a valid assumption, the effects of cartilage rings on airflow and particle deposition in the lungs was determined through conducting simulations with two CFD packages, Fluent and CFX. A smooth walled model and a ringed model of the trachea and main bronchi were created based on idealized models with realistic characteristics. Turbulent velocity profiles were implemented at the inlet of the trachea to account for the laryngeal jet at 15, 30 and 60 lpm's, while random and uniform distributions of particles were injected into the airways. Deposition of particles through sedimentation and impaction were recorded and compared for each model at each flow rate. The results of this work show that the effects of cartilage rings increase with the size of particles and flow rate.

Extinguishing the voices: living with the ghost of the disenfranchised

As a user of the mental health service, Rob has first-hand experience of the marginalization that accompanies a mental health label. In seeking to validate his experience, centre and assimilate the shadow within, he has participated in teaching students within mental health programmes. Tessa in her role as an academic has sought to validate her experience of teenage pregnancy in a world that denied her experience. The chance meeting of these two people on their respective journeys highlights the voices that have not been heard and the ghosts that link them. Journeys that seek to reconcile memory and truth and entwine numinance within the narrative of mental health.