Effects of a helium/oxygen mixture on individuals' lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases.

Background: Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22%) to that of medical air.

Methods: The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD) participants, both moderate and severe (6 participants in each disease group, a total of 30); at rest and during submaximal cycling exercise with equivalent work rates.

Understanding HIV-infected patients' experiences with PEPFAR-associated transitions at a Centre of Excellence in KwaZulu Natal, South Africa: a qualitative study.

South Africa was the largest recipient of funding from the President's Emergency Plan for AIDS Relief (PEPFAR) for antiretroviral therapy (ART) programs from 2004 to 2012. Funding decreases have led to transfers from hospital and non-governmental organization-based care to government-funded, community-based clinics. We conducted semi-structured interviews with 36 participants to assess patient experiences related to transfer of care from a PEPFAR-funded, hospital-based clinic in Durban to either primary care clinics or hospital-based clinics.

Pharmacokinetic analysis of the chronic administration of the inert gases Xe and Ar using a physiological based model.

Background: New gas therapies using inert gases such as xenon and argon are being studied, which would require chronically administered repeating doses. The pharmacokinetics of this type of administration has not been addressed in the literature.

Methods: A physiologically based pharmacokinetics (PBPK) model for humans, pigs, mice, and rats has been developed to investigate the unique aspects of the chronic administration of inert gas therapies.

What Causes Uneven Aerosol Deposition in the Bronchoconstricted Lung? A Quantitative Imaging Study.

Background: A previous PET-CT imaging study of 14 bronchoconstricted asthmatic subjects showed that peripheral aerosol deposition was highly variable among subjects and lobes. The aim of this work was to identify and quantify factors responsible for this variability.

Methods: A theoretical framework was formulated to integrate four factors affecting aerosol deposition: differences in ventilation, in how air vs.

Parental support and adolescent motivation for dieting: the Self-Determination Theory perspective.

This article focuses on parents' role in overweight adolescents' motivation to diet and successful weight loss. The study employed Self-Determination Theory (SDT) as the theoretical framework (Deci & Ryan, 2000, 2011). Ninety-nine participants (ages 20-30) who had been overweight during adolescence according to their Body Mass Index (BMI mean = 25, SD = 1.

Controlled, Parametric, Individualized, 2-D and 3-D Imaging Measurements of Aerosol Deposition in the Respiratory Tract of Asthmatic Human Subjects for Model Validation.

Background: Computer modeling is used to predict inhaled aerosol deposition in the lung based on definition of the aerosol characteristics and the breathing pattern and airway anatomy of the subject. Validation of the models is limited by the lack of detailed experimental data. Three-dimensional imaging provides an opportunity to address this unmet need.

Factors associated with lack of viral suppression at delivery among highly active antiretroviral therapy-naive women with HIV: a cohort study.

Background: A high delivery maternal plasma HIV-1 RNA level (viral load [VL]) is a risk factor for mother-to-child transmission and poor maternal health.

Objective: To identify factors associated with detectable VL at delivery despite initiation of highly active antiretroviral therapy (HAART) during pregnancy.

Design: Multicenter observational study.

High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance.

The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current.

Trends in CD4 count at presentation to care and treatment initiation in sub-Saharan Africa, 2002-2013: a meta-analysis.

Background: Both population- and individual-level benefits of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) are contingent on early diagnosis and initiation of therapy. We estimated trends in disease status at presentation to care and at ART initiation in sub-Saharan Africa.

Methods: We searched PubMed for studies published January 2002-December 2013 that reported CD4 cell count at presentation or ART initiation among adults in sub-Saharan Africa.

A new approach to the dynamics of oxygen capture by the human lung.

Oxygen capture in the lung results from the intimate dynamic interaction between the space- and time-dependent oxygen partial pressure that results from convection-diffusion and oxygen extraction from the alveolar gas and the space and time dependence of oxygen trapping by the red blood cells flowing in the capillaries. The complexity of the problem can, however, be reduced due to the fact that the systems obey different time scales: seconds for the gas phase transport and tenths of seconds for oxygen trapping by blood. This results first from a dynamical study of gas transport in a moving acinus and second from a new theory of dynamic oxygen trapping in the capillaries.

Fear conditioning leads to alteration in specific genes expression in cortical and thalamic neurons that project to the lateral amygdala.

RNA transcription is needed for memory formation. However, the ability to identify genes whose expression is altered by learning is greatly impaired because of methodological difficulties in profiling gene expression in specific neurons involved in memory formation. Here, we report a novel approach to monitor the expression of genes after learning in neurons in specific brain pathways needed for memory formation.

Understanding treatment refusal among adults presenting for HIV-testing in Soweto, South Africa: a qualitative study.

HIV treatment initiatives have focused on increasing access to antiretroviral therapy (ART). There is growing evidence, however, that treatment availability alone is insufficient to stop the epidemic. In South Africa, only one third of individuals living with HIV are actually on treatment.

Where will the money come from? Alternative mechanisms to HIV donor funding.

Background: Donor funding for HIV programs has flattened out in recent years, which limits the ability of HIV programs worldwide to achieve universal access and sustain current progress. This study examines alternative mechanisms for resource mobilization.

Methods: Potential non-donor funding sources for national HIV responses in low- and middle-income countries were explored through literature review and Global Fund documentation, including data from 17 countries.

Organic cleanliness of the Mars Science Laboratory sample transfer chain.

One of the primary science goals of the Mars Science Laboratory (MSL) Rover, Curiosity, is the detection of organics in Mars rock and regolith. To achieve this, the Curiosity rover includes a robotic sampling system that acquires rock and regolith samples and delivers it to the Sample Analysis at Mars (SAM) instrument on board the rover. In order to provide confidence that any significant organics detection result was Martian and not terrestrial in origin, a requirement was levied on the flight system (i.

Determination of regional lung air volume distribution at mid-tidal breathing from computed tomography: a retrospective study of normal variability and reproducibility.

Background: Determination of regional lung air volume has several clinical applications. This study investigates the use of mid-tidal breathing CT scans to provide regional lung volume data.

Methods: Low resolution CT scans of the thorax were obtained during tidal breathing in 11 healthy control male subjects, each on two separate occasions.

TED-Time and life saving External Defibrillator for home-use.

Sudden Cardiac Death--SCD --is a major unmet health problem that needs urgent and prompt solution. AICDs are very expensive, risky and indicated for a small group of patients, at the highest risk. AEDs--Automatic External Defibrillators--are designed for public places and although safe, cannot enter the home-market due to their cost and need for constant, high-cost maintenance.

Inhalation pressure distributions for medical gas mixtures calculated in an infant airway morphology model.

A numerical pressure loss model previously used for adult human airways has been modified to simulate the inhalation pressure distribution in a healthy 9-month-old infant lung morphology model. Pressure distributions are calculated for air as well as helium and xenon mixtures with oxygen to investigate the effects of gas density and viscosity variations for this age group. The results indicate that there are significant pressure losses in infant extrathoracic airways due to inertial effects leading to much higher pressures to drive nominal flows in the infant airway model than for an adult airway model.

Depression and chronic kidney disease: A review for clinicians.

Objective: To review the recent academic literature surrounding the prevalence, aetiopathology, associations and management of depression in chronic kidney disease (CKD), in order to provide a practical and up-to-date resource for clinicians.

Methods: We conducted electronic searches of the following databases: MEDLINE, EMBASE and PsycINFO. The main search terms were: depression, mood disorders, depressive disorder, mental illness, in combination with kidney disease, renal insufficiency, dialysis, kidney failure.

Radiologically isolated syndrome: 5-year risk for an initial clinical event.

Objective: To report the 5-year risk and to identify risk factors for the development of a seminal acute or progressive clinical event in a multi-national cohort of asymptomatic subjects meeting 2009 RIS Criteria.

Methods: Retrospectively identified RIS subjects from 22 databases within 5 countries were evaluated. Time to the first clinical event related to demyelination (acute or 12-month progression of neurological deficits) was compared across different groups by univariate and multivariate analyses utilizing a Cox regression model.