676 research outputs found
Diverse soil carbon dynamics expressed at the molecular level
The stability and potential vulnerability of soil organic matter (SOM) to global change remains incompletely understood due to the complex processes involved in its formation and turnover. Here we combine compound-specific radiocarbon analysis with fraction-specific and bulk-level radiocarbon measurements in order to further elucidate controls on SOM dynamics in a temperate and sub-alpine forested ecosystem. Radiocarbon contents of individual organic compounds isolated from the same soil interval generally exhibit greater variation than those among corresponding operationally-defined fractions. Notably, markedly older ages of long-chain plant leaf wax lipids (n-alkanoic acids) imply that they reflect a highly stable carbon pool. Furthermore, marked 14C variations among shorter- and longer-chain n-alkanoic acid homologues suggest that they track different SOM pools. Extremes in SOM dynamics thus manifest themselves within a single compound class. This exploratory study highlights the potential of compound-specific radiocarbon analysis for understanding SOM dynamics in ecosystems potentially vulnerable to global change
Increased influence and collaboration: a qualitative study of patients’ experiences of community treatment orders within an assertive community treatment setting
Multifunctional Nanohybrid Based on Porous Silicon Nanoparticles, Gold Nanoparticles and Acetalated Dextran for Liver Regeneration and Acute Liver Failure Theranostics
Herein, a novel nanohybrid based on porous silicon, gold nanoparticles (Au NPs), and acetalated dextran (DPSi/DAu@AcDEX) is reported to encapsulate and deliver one drug and increase the computer tomography (CT) signal for acute-liver-failure (ALF) theranostics. A microfluidic-assisted method is used to co-encapsulate different NPs in a single step. By alternating the surface properties of different NPs and by modulating the composition of the organic phase, both PSi and Au NPs are effectively encapsulated into the polymer matrix simultaneously, thus further achieving a multifunctional application. This system can be used to identify pathologically changes in the tissues and selectively deliver drugs to these sites. The loading of a therapeutic compound (XMU-MP-1) improves the drug solubility, precise, in situ drug delivery, and the drug-functioning time. In vivo results confirm a superior treatment effect and better compliance of this newly developed nanoformulation than free compound. This nanosystem plays a crucial role in targeting the lesion area, thus increasing the local drug concentration important for ALF reverse-effect. Moreover, the residence of Au NPs within the matrix further endows our system for CT-imaging. Altogether, these results support that this nanohybrid is a potential theranostic platform for ALF.Peer reviewe
Possible links between extreme oxygen perturbations and the Cambrian radiation of animals
The role of oxygen as a driver for early animal evolution is widely debated. During the
Cambrian explosion, episodic radiations of major animal phyla occurred coincident with
repeated carbon isotope fluctuations. However, the driver of these isotope fluctuations and
potential links to environmental oxygenation are unclear. Here, we report high-resolution
carbon and sulphur isotope data for marine carbonates from the south-eastern Siberian
Platform, which documents the canonical explosive phase of the Cambrian radiation from
~524 to ~514 Myr ago. These analyses demonstrate a strong positive covariation between
carbonate
13C and carbonate-associated sulphate
34S through five isotope cycles.
Biogeochemical modelling suggests that this isotopic coupling reflects periodic oscillations
in atmospheric O2 and the extent of shallow ocean oxygenation which, remarkably, directly
coincides with episodic maxima in biodiversity of animal phyla. Conversely, the subsequent
Botoman–Toyonian animal extinction events (~514 to ~512 Myr ago) coincided with
decoupled isotope records that suggest a shrinking marine sulphate reservoir and expanded
shallow marine anoxia. These observations demonstrate that fluctuations in oxygen
availability in the shallow marine realm exerted a primary control on the timing and tempo
of biodiversity radiations at a crucial phase in the early history of animal life
11Beta‐hydroxysteroid dehydrogenase‐1 deficiency or inhibition enhances hepatic myofibroblast activation in murine liver fibrosis
The Matter Power Spectrum of Dark Energy Models and the Harrison-Zel'dovich Prescription
According to the Harrison-Zel'dovich prescription, the amplitude of matter
density perturbations at horizon crossing is the same at all scales. Based on
this prescription, we show how to construct the matter power spectrum of
generic dark energy models from the power spectrum of a CDM model
without the need of solving in full the dynamical equations describing the
evolution of all energy density perturbations. Our approach allows to make
model predictions of observables that can be expressed in terms of the matter
power spectrum alone, such as the amplitude of matter fluctuations, peculiar
velocities, cosmic microwave background temperature anisotropies on large
angular scales or the weak lensing convergence spectrum. Then, models that have
been tested only at the background level using the rate of the expansion of the
Universe can now be tested using data on gravitational clustering and on large
scale structure. This method can save a lot of effort in checking the validity
of dark energy models. As an example of the accurateness of the approximation
used, we compute the power spectrum of different dark energy models with
constant equation of state parameter (, -0.5 and -0.8, ruled out
by observations but easy to compare to numerical solutions) using our
methodology and discuss the constraints imposed by the low multipoles of the
cosmic microwave background.Comment: 11 pages, 3 figures. Key words: Physical cosmology, cosmological
perturbations, matter power spectrum, dark energy. Further text, figures, and
references added to emphasize the usefulness of the method. Publshed in JCAP
(April 2012
Emerging immunopharmacological targets in multiple sclerosis.
Inflammatory demyelination of the central nervous system (CNS) is the hallmark of multiple sclerosis (MS), a chronic debilitating disease that affects more than 2.5 million individuals worldwide. It has been widely accepted, although not proven, that the major pathogenic mechanism of MS involves myelin-reactive T cell activation in the periphery and migration into the CNS, which subsequently triggers an inflammatory cascade that leads to demyelination and axonal damage. Virtually all MS medications now in use target the immune system and prevent tissue damage by modulating neuroinflammatory processes. Although current therapies such as commonly prescribed disease-modifying medications decrease the relapse rate in relapsing-remitting MS (RRMS), the prevention of long-term accumulation of deficits remains a challenge. Medications used for progressive forms of MS also have limited efficacy. The need for therapies that are effective against disease progression continues to drive the search for novel pharmacological targets. In recent years, due to a better understanding of MS immunopathogenesis, new approaches have been introduced that more specifically target autoreactive immune cells and their products, thus increasing specificity and efficacy, while reducing potential side effects such as global immunosuppression. In this review we describe several immunopharmacological targets that are currently being explored for MS therapy
Self-reported smoking cessation activities among Swiss primary care physicians
ABSTRACT: BACKGROUND: Individual counselling, pharmacotherapy, and group therapy are evidence-based interventions that help patients stop smoking. Acupuncture, hypnosis, and relaxation have no demonstrated efficacy on smoking cessation, whereas self-help material may only have a small benefit. The purpose of this study is to assess physicians' current clinical practice regarding smokers motivated to stop smoking. METHODS: The survey included 3385 Swiss primary care physicians. Self-reported use of nine smoking cessation interventions was scored. One point was given for each positive answer about practicing interventions with demonstrated efficacy, i.e. nicotine replacement therapy, bupropion, counselling, group therapy, and smoking cessation specialist. No points were given for the recommendation of acupuncture, hypnosis, relaxation, and self-help material. Multivariable logistic analysis was performed to identify factors associated with a good practice score, defined as >1. RESULTS: The response rate was 55%. Respondents were predominately over the age of 40 years (88%), male (79%), and resided in urban areas (74%). Seventeen percent reported being smokers. Most of the physicians prescribed nicotine replacement therapy (84%), bupropion (65%), or provided counselling (70%). A minority of physicians recommended acupuncture (26%), hypnosis (8%), relaxation (7%), or self-help material (24%). A good practice score was obtained by 85% of respondents. Having attended a smoking cessation training program was the only significant predictor of a good practice score (odds ratio: 6.24 , 95% CI 1.95-20.04). CONCLUSION: The majority of respondents practice recommended smoking cessation interventions. However, there is room for improvement and implementing an evidence-based smoking cessation-training program could provide additional benefit
Impaired neonatal macrophage phagocytosis is not explained by overproduction of prostaglandin E2
<p>Abstract</p> <p>Background</p> <p>Neonates and young infants manifest increased susceptibility to bacterial, viral and fungal lung infections. Previous work has identified a role for eicosanoids in mediating host defense functions of macrophages. This study examines the relationship between alveolar macrophage (AM) host defense and production of lipid mediators during the neonatal period compared to adult AMs.</p> <p>Methods</p> <p>AMs were harvested from young (day 7 and day 14) and adult (~10 week) rats. The functionality of these cells was assessed by examining their ability to phagocytose opsonized targets, produce cytokines, eicosanoids and intracellular cAMP measured by enzyme immunoassays, and gene expression of proteins, enzymes and receptors essential for eicosanoid generation and phagocytosis measured by real time RT-PCR.</p> <p>Results</p> <p>AMs from young animals (day 7 and 14) were defective in their ability to phagocytose opsonized targets and produce tumor necrosis factor (TNF)- α. In addition, young AMs produce more prostaglandin (PG) E<sub>2</sub>, a suppressor of host defense, and less leukotriene (LT) B<sub>4</sub>, a promoter of host defense. Young AMs express higher levels of enzymes responsible for the production of PGE<sub>2 </sub>and LTB<sub>4</sub>; however, there was no change in the expression of E prostanoid (EP) receptors or LT receptors. Despite the similar EP profiles, young AMs are more responsive to PGE<sub>2 </sub>as evidenced by their increased production of the important second messenger, cyclic AMP. In addition, young AMs express higher levels of PDE3B and lower levels of PDE4C compared to adult AMs. However, even though the young AMs produced a skewed eicosanoid profile, neither the inhibition of PGE<sub>2 </sub>by aspirin nor the addition of exogenous LTB<sub>4 </sub>rescued the defective opsonized phagocytosis. Examination of a receptor responsible for mediating opsonized phagocytosis showed a significant decrease in the gene expression levels of the Fcgamma receptor in young (day 7) AMs compared to adult AMs.</p> <p>Conclusion</p> <p>These results suggest that elevated production of PGE<sub>2 </sub>and decreased production of LTB<sub>4 </sub>do not contribute to impaired opsonized macrophage phagocytosis and highlight an important difference between young and adult AMs.</p
An unusual case of chronic meningitis
BACKGROUND: Chronic meningitis is defined as symptoms and signs of meningeal inflammation and persisting cerebrospinal fluid abnormalities such as elevated protein level and pleocytosis for at least one month. CASE PRESENTATION: A 62-year-old woman, of unremarkable past medical history, was admitted to hospital for investigation of a four-week history of vomiting, malaise an associated hyponatraemia. She had a low-grade pyrexia with normal inflammatory markers. A CT brain was unremarkable and a contrast MRI brain revealed sub-acute infarction of the right frontal cortex but with no evidence of meningeal enhancement. Due to increasing confusion and patient clinical deterioration a lumbar puncture was performed at 17 days post admission. This revealed gram-negative coccobacilli in the CSF, which was identified as Neisseria meningitidis group B. The patient made a dramatic recovery with high-dose intravenous ceftriaxone antibiotic therapy for meningococcal meningitis. CONCLUSIONS: 1) Chronic bacterial meningitis may present highly atypically, particularly in the older adult. 2) There may be an absent or reduced febrile response, without a rise in inflammatory markers, despite a very unwell patient. 3) Early lumbar puncture is to be encouraged as it is essential to confirm the diagnosis.4) Despite a delayed diagnosis appropriate antibiotic therapy can still lead to a good outcome
- …