Performance of Unsaturated Compacted Clay Under Repeated Loading Effects of Confining Pressure, Initial Compaction Effort and Water Content

While a significant number of geotechnical structures are subjected to static loading, many, such as avement subgrade, also are subjected to cyclic or dynamic loading. While the performance of saturated soils under repeated, cyclic or dynamic loading conditions is still a topic of research, similar interests are growing when the soilcondition is unsaturated. This paper examines the performance of unsaturated soils under repeated loading. As part of the research, a triaxial system was developed which incorporates small strain measurements using Hall-effect transducers, in addition to suction measurements taken using a psychrometer. Tests were conducted on samples of kaolin under constant water mass conditions. The results address the effects of compaction effort and water content at the time of compaction on the overall performance of unsaturated soils, under different amplitudes of loading and different confining pressures. The results show that suction in the sample reduced with increasing number of loading cycles of the same magnitude. The resilient modulus initially increased with increasing water content up to approximately optimum water content, and substantially reduced with further increase in water content. Key Words: suction, resilient modulus, subgrade, repeated loading, small strain measurements, compaction.

Moxifloxacin sensitivity of respiratory pathogens in the United Kingdom

The in vitro activity of moxifloxacin and comparator agents against respiratory isolates from a range of geographically distinct centres around the United Kingdom was investigated in the following study. Clinical isolates of Streptococcus pneumoniae (n = 257), Haemophilus influenzae (n = 399) and Moraxella catarrhalis (n = 253) were obtained between March 1998 and April 1999 from nine centres in the United Kingdom. Sensitivity was determined by testing each isolate for its minimum inhibitory concentration (MIC) by agar dilution. Against Streptococcus pneumoniae moxifloxacin and grepafloxacin were the most active (MIC90 = 0.25 mg/l). Trovafloxacin and sparfloxacin were the next most active (MIC90 = 0.5 mg/l) followed by levofloxacin and ciprofloxacin. MIC90 values of the six fluoroquinolones versus H. influenzae ranged from ciprofloxacin > levofloxacin. Against M. catarrhalis the lowest MIC90 was that of grepafloxacin at 0.0625 mg/l followed by moxifloxacin, sparfloxacin, levofloxacin and ciprofloxacin. Trovafloxacin demonstrated the highest MIC90 at 0.5 mg/l. These results demonstrate that moxifloxacin has superior in vitro activity against respiratory tract pathogens than any other comparator quinolones available for clinical use.

Development of a novel experimental model to investigate radiobiological implications of respiratory motion in advanced radiotherapy

Respiratory motion introduces complex spatio-temporal variations in the dosimetry of radiotherapy. There is a paucity of literature investigating the radiobiological consequences of intrafraction motion and concerns regarding the impact of movement when applied to cancer cell lines in vitro exist. We have addressed this by developing a novel model which accurately replicates respiratory motion under experimental conditions to allow clinically relevant irradiation of cell lines. A bespoke phantom and motor driven moving platform was adapted to accommodate flasks containing medium and cells in order to replicate respiratory motion using varying frequencies and amplitude settings. To study this effect on cell survival in vitro, dose response curves were determined for human lung cancer cell lines H1299 and H460 exposed to a uniform 6 MV radiation field under moving or stationary conditions. Cell survival curves showed no significant difference between irradiation at different dose points for these cell lines in the presence or absence of motion. These data indicate that motion of unshielded cells in vitro does not affect cell survival in the presence of uniform irradiation. This model provides a novel research platform to investigate the radiobiological consequences of respiratory motion in radiotherapy.

The management of cough:a clinical year in review

As the number of published articles in the field of cough increases year on year, it is sometimes helpful to pause and review what might have passed us by. This "Clinical Year in Review" provides an opportunity to reflect on a number of important studies reported in the area of both adult and pediatric cough. It would be impossible to cover all the important published literature; therefore, this effort has been confined to selected topics published in the last 12 months with direct relevance to the clinical management, measurement, and treatment of cough. While this article reflects a personal commentary of the literature, it is hoped that it will contribute to improving "evidence-based" care for the many individuals burdened with a troublesome cough.

The experiences of palliative care health service provision for people with non-malignant respiratory disease and their caregivers: an all-Ireland study

Aim: To explore the perception of palliative care provision for people with non-malignant respiratory disease from the perspective of bereaved caregivers.

Background: It is recognized that the majority of patients diagnosed with a malignant disease will have access to palliative care provision. However, it is less clear if the same standards of palliative care are available to those with non-malignant respiratory disease in Northern Ireland and the Republic of Ireland.

Design: A qualitative study based on broad interpretivism.

Methods: This research is a PhD study funded by the Department of Education and Learning in Northern Ireland (awarded February 2011). Data collection will consist of two stages; interviews with 20 bereaved caregivers of people who have died 3–18 months previously with a diagnosis of non-malignant respiratory disease and four focus groups with healthcare professionals involved in the care of this client group. This study will be carried out at four healthcare sites across the Island of Ireland. The data will be analysed using thematic content analysis. Research Ethics committee approval was obtained (March 2012).

Discussion: This research will explore the experiences of patients with Chronic Obstructive Pulmonary Disease, Interstitial Lung Disease and Bronchiectasis and their caregivers from the perspective of the bereaved caregiver. The outcomes of this study will provide a critical first step in the development of more responsive palliative care for this client group and have important implications for future practice and policy in the palliative care provided to this client group.

Host cell kinases, α5 and β1 integrins, and Rac1 signalling on the microtubule cytoskeleton are important for non-typable Haemophilus influenzae invasion of respiratory epithelial cells

Non-typable Haemophilus influenzae (NTHi) is a common commensal of the human nasopharynx, but causes opportunistic infection when the respiratory tract is compromised by infection or disease. The ability of NTHi to invade epithelial cells has been described, but the underlying molecular mechanisms are poorly characterized. We previously determined that NTHi promotes phosphorylation of the serine-threonine kinase Akt in A549 human lung epithelial cells, and that Akt phosphorylation and NTHi cell invasion are prevented by inhibition of phosphoinositide 3-kinase (PI3K). Because PI3K-Akt signalling is associated with several host cell networks, the purpose of the current study was to identify eukaryotic molecules important for NTHi epithelial invasion. We found that inhibition of Akt activity reduced NTHi internalization; differently, bacterial entry was increased by phospholipase C?1 inhibition but was not affected by protein kinase inhibition. We also found that a5 and ß1 integrins, and the tyrosine kinases focal adhesion kinase and Src, are important for NTHi A549 cell invasion. NTHi internalization was shown to be favoured by activation of Rac1 guanosine triphosphatase (GTPase), together with the guanine nucleotide exchange factor Vav2 and the effector Pak1. Also, Pak1 might be associated with inactivation of the microtubule destabilizing agent Op18/stathmin, to facilitate microtubule polymerization and NTHi entry. Conversely, inhibition of RhoA GTPase and its effector ROCK increased the number of internalized bacteria. Src and Rac1 were found to be important for NTHi-triggered Akt phosphorylation. An increase in host cyclic AMP reduced bacterial entry, which was linked to protein kinase A. These findings suggest that NTHi finely manipulates host signalling molecules to invade respiratory epithelial cells.

Pneumonia and lower respiratory infections in nursing home residents:Predictors of hospitalization and mortality

OBJECTIVES: To compare predictors of hospitalization and death in nursing home residents with pneumonia and other lower respiratory infections (LRIs). DESIGN: A nested cohort study. SETTING: Nine nursing homes in southern Ontario. PARTICIPANTS: Three hundred fifty-three nursing home residents with LRIs (enrolled in the control arm of a clinical trial). MEASUREMENTS: Comorbidities, vaccination status, age, health-related quality of life, functional status, and vital statistics were evaluated as potential predictors of hospitalization and mortality at 30 days. RESULTS: Moderate to high disease severity score on a practical severity scale was a strong independent predictor of hospitalization (odds ratio (OR)=7.12, P