Effects of elevated atmospheric CO2 on soil microbial biomass, activity, and diversity in a chaparral ecosystem.

This study reports the effects of long-term elevated atmospheric CO2 on root production and microbial activity, biomass, and diversity in a chaparral ecosystem in southern California. The free air CO2 enrichment (FACE) ring was located in a stand dominated by the woody shrub Adenostoma fasciculatum. Between 1995 and 2003, the FACE ring maintained an average daytime atmospheric CO2 concentration of 550 ppm.

Recovery from stroke: differences between subtypes.

The objective of this study was to compare the differences in patterns of recovery and incidence of medical complications in hemorrhagic and ischemic stroke patients admitted for rehabilitation, using a retrospective case series design. It was set in three tertiary care facilities in London, Ontario, Canada. Eight-hundred-and-nineteen consecutive patients, admitted from 1997 to 2001 for rehabilitation following cerebrovascular event, were reviewed.

Measurements of regional alveolar oxygen pressure using hyperpolarized 3He MRI.

Rationale And Objectives: The aim of this work is to review hyperpolarized (HP) helium-3 (3He) magnetic resonance imaging (MRI) methods to measure regional alveolar oxygen partial pressure (P(A)O2) and oxygen depletion rate (R) in the lung. We point out limitations of the methods and suggest improvements to increase their accuracy.

Materials And Methods: P(A)O2 and R can be extracted from series of HP gas images acquired during breath hold by making use of the depolarizing effect of oxygen on HP gas.

Renal and vestibular toxicity due to inhaled tobramycin in a lung transplant recipient.

Chronic rejection is the major hurdle to long-term survival after lung transplantation. Endobronchial infection with Pseudomonas aeruginosa is common in patients with chronic rejection and this may further contribute to deterioration of the allograft. Inhaled tobramycin is commonly used to treat P aeruginosa airways infection in patients with cystic fibrosis.

Quantitative assessment of emphysema using hyperpolarized 3He magnetic resonance imaging.

In this experiment, Sprague-Dawley rats with elastase-induced emphysema were imaged using hyperpolarized (3)He MRI. Regional fractional ventilation r, the fraction of gas replaced with a single tidal breath, was calculated from a series of images in a wash-in study of hyperpolarized gas. We compared the regional fractional ventilation in these emphysematous rats to the regional fractional ventilations we calculated from a previous baseline study in healthy Sprague-Dawley rats.

A comparison of the Barthel Index and the Functional Independence Measure as outcome measures in stroke rehabilitation: patterns of disability scale usage in clinical trials.

In order to compare the frequency and patterns of use of the Barthel Index (BI) and Functional Independence Measure (FIM) in stroke rehabilitation trials, all randomized controlled trials (RCTs) of stroke rehabilitation published between 1968 and 2002 were identified and reviewed to determine the frequency with which the BI and FIM measures were used relative to other measures of disability. The date and location of each study citing either the FIM or the BI were also recorded. Studies were assigned ratings of methodological quality based on the physiotherapy evidence database (PEDro) scoring system.

Ultrasonic biophysical measurements in the normal human fetus for optimal design of the monolithic fetal pacemaker.

Ultrasound measurements, including xiphoid-to-pericardial distance and deployment angle, were made on human fetuses as a function of gestational age for the purpose of assessing the likelihood of 3 failure modes of a monolithic fetal pacemaker, including primary positioning failure due to device length and secondary dislodgement failure due to somatic growth. The small variation of the measurements over the gestational age range relevant to device implantation for the major indications of the device (for complete heart block complicated by hydrops and for bradycardia risk after fetal surgery or intrauterine intervention) predicts a small likelihood of these failure modes.

Matrix diffusion-derived plume attenuation in fractured bedrock.

Matrix diffusion can attenuate the rate of plume migration in fractured bedrock relative to the rate of ground water flow for both conservative and nonconservative solutes of interest. In a system of parallel, equally spaced constant aperture fractures subject to steady-state ground water flow and an infinite source width, the degree of plume attenuation increases with time and travel distance, eventually reaching an asymptotic level. The asymptotic degree of plume attenuation in the absence of degradation can be predicted by a plume attenuation factor, beta, which is readily estimated as R' (phi(m)/phi(f)), where R' is the retardation factor in the matrix, phi(m) is the matrix porosity, and phi(f) is the fracture porosity.

Hyperpolarized helium-3 MR imaging of pulmonary function.

Recent advances in HP MR imaging contrast agents have led to novel tests of pulmonary function. Many of these tests show promise in the clinical arena.

Comparative genomic hybridization using oligonucleotide microarrays and total genomic DNA.

Array-based comparative genomic hybridization (CGH) measures copy-number variations at multiple loci simultaneously, providing an important tool for studying cancer and developmental disorders and for developing diagnostic and therapeutic targets. Arrays for CGH based on PCR products representing assemblies of BAC or cDNA clones typically require maintenance, propagation, replication, and verification of large clone sets. Furthermore, it is difficult to control the specificity of the hybridization to the complex sequences that are present in each feature of such arrays.

A small animal model of regional alveolar ventilation using HP 3He MRI1.

Rationale And Objectives: The aim of this study was to establish a standardized procedure for the measurement of regional fractional ventilation in a healthy rat model as a baseline for further studies of pulmonary disorder models.

Materials And Methods: The lungs of five healthy male Sprague-Dawley rats were imaged using hyperpolarized helium-3 magnetic resonance imaging. From these images, regional fractional ventilation was calculated and maps generated detailing the distribution of fractional ventilation in the lung.

Translating research into practice: speeding the adoption of innovative health care programs.

For this study, the authors conducted case studies of four varied clinical programs to learn key factors influencing the diffusion and adoption of evidence-based innovations in health care. They found that the success and speed of the adoption/diffusion process depend on: the roles of senior management and clinical leadership; the generation of credible supportive data; an infrastructure dedicated to translating the innovation from research into practice; the extent to which changes in organizational culture are required; and the amount of coordination needed across departments or disciplines. The translation process also depends on the characteristics and resources of the adopting organization, and on the degree to which people believe that the innovation responds to immediate and significant pressures in their environment.

Determination of regional VA/Q by hyperpolarized 3He MRI.

Alveolar ventilation/perfusion ratio (VA/Q) is a key parameter in functional imaging of the lung. Herein, regional VA/Q was calculated from regional values of alveolar partial pressure of oxygen (PAO2) measured by hyperpolarized 3He gas MRI (HP 3He MRI). Yorkshire pigs (n = 7, mean weight = 25 kg) were paralyzed and maintained under isoflurane anesthesia.

Redefining treatment in COPD: new directions in bronchodilator therapy.

COPD is a growing international health concern and it is estimated that by the year 2020 it will rank fifth as a cause of disability worldwide. In response to this problem, the World Health Organization and the US National Institutes of Health convened a panel of experts to draft a consensus strategy to treat patients with COPD. Called the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, they are designed to define and stage the severity of COPD, make recommendations for treatment, and to expand global awareness of the disease.

Seasonal changes in an alpine soil bacterial community in the colorado rocky mountains.

The period when the snowpack melts in late spring is a dynamic time for alpine ecosystems. The large winter microbial community begins to turn over rapidly, releasing nutrients to plants. Past studies have shown that the soil microbial community in alpine dry meadows of the Colorado Rocky Mountains changes in biomass, function, broad-level structure, and fungal diversity between winter and early summer.

Saline-linked surface radiofrequency ablation: factors affecting steam popping and depth of injury in the pig liver.

Summary Background Data: Saline-linked surface radiofrequency (RF) ablation is a new technique for applying RF energy to surfaces. The surface is cooled, which prevents charring and results in deeper coagulation. However, subsurface heating may lead to steam formation and a form of tissue disruption called steam popping.

Detection of simulated pulmonary embolism in a porcine model using hyperpolarized 3He MRI.

Several radiological imaging modalities are available to assist with the clinical diagnosis of pulmonary embolism (PE). The most frequently used techniques-nuclear medicine ventilation-perfusion (VP) scan, computed tomography (CT), magnetic resonance angiography (MRA), and pulmonary angiography (PA)-all have literature-supported, substantial limitations with respect to timeliness and patient safety. Hyperpolarized 3He magnetic resonance gas distribution imaging (HP 3He MRI) recently has shown potential as a safer and faster alternative.

Molecular and metabolic characterization of cold-tolerant alpine soil Pseudomonas sensu stricto.

Alpine soils undergo dramatic temporal changes in their microclimatic properties, suggesting that the bacteria there encounter uncommon shifting selection gradients. Pseudomonads constitute important members of the alpine soil community. In order to characterize the alpine Pseudomonas community and to assess the impact of shifting selection on this community, we examined the ability of cold-tolerant Pseudomonas isolates to grow on a variety of carbon sources, and we determined their phylogenetic relationships based on 16S ribosomal DNA sequencing.

Seasonal dynamics of previously unknown fungal lineages in tundra soils.

The finding that microbial communities are active under snow has changed the estimated global rates of biogeochemical processes beneath seasonal snow packs. We used microbiological and molecular techniques to elucidate the phylogenetic composition of undersnow microbial communities in Colorado, the United States. Here, we show that tundra soil microbial biomass reaches its annual peak under snow, and that fungi account for most of the biomass.

Bronchoscopy for atelectasis in the ICU: a case report and review of the literature.

Fiberoptic bronchoscopy has become a commonplace procedure in ICUs. Despite the fact that one of the most common indications for bronchoscopy is the presence of retained secretions and atelectasis, there is little research dedicated to its safety and utility in this clinical situation. This article presents a case of an intubated trauma victim who had undergone numerous bronchoscopic procedures, with varying degrees of success, for retained secretions and atelectasis.

Operating characteristics of hyperpolarized 3He and arterial spin tagging in MR imaging of ventilation and perfusion in healthy subjects.

Rationale And Objectives: The authors tested the feasibility of a magnetic resonance (MR) imaging method combining the use of hyperpolarized helium 3 (3He) for ventilation imaging and an arterial spin-tagging sequence for perfusion imaging in six healthy human subjects.

Materials And Methods: High-resolution sagittal images depicting 3He distribution were acquired after the subjects' inhalation of 500 mL of laser-hyperpolarized 3He produced by spin-exchange optical pumping. Perfusion MR imaging was performed with a steady-state arterial spin-tagging sequence that enabled the acquisition of three-dimensional images of pulmonary perfusion without the need for subject breath holding.

Maintaining hydraulic control using deep rooted tree systems.

Groundwater phytotechnology systems are currently being used to control the migration of contaminant plumes and remove groundwater that flows into containment areas. Trees in such systems function by reducing recharge and using groundwater via transpiration. A stand of deep-rooted trees can act as a biological "pump", removing a substantial amount of water from the saturated zone.

Co-registration of acquired MR ventilation and perfusion images--validation in a porcine model.

Under controlled imaging conditions, functional, co-registered ventilation and perfusion images were obtained for quantitative MRI assessment of pulmonary function. Experiments were conducted on 25-35 kg Yorkshire pigs (N = 5) under ketamine/isoflurane anesthesia. Ventilation and perfusion MR images were obtained using laser polarized gas and gadolinium (Gd), respectively.