2,115 research outputs found

    Decreased mass specific respiration under experimental warming is robust to the microbial biomass method employed

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    Hartley et al. question whether reduction in Rmass, under experimental warming, arises because of the biomass method. We show the method they treat as independent yields the same result. We describe why the substrate-depletion hypothesis may not solely explain observed responses, and urge caution in interpretation of the seasonal data. © 2009 Blackwell Publishing Ltd/CNRS

    Effect of clay and iron sulphate on volatile and water-extractable organic compounds in bamboo biochars

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    Improved plant disease resistance, seed germination and plant productivity have recently been associated with mineral-enhanced biochars. This has generated interest in characterizing those biochar organic compounds which may contribute to their favorable properties. This study builds on recent physico-chemical characterization of a series of mineral-enhanced bamboo biochars produced between 350 and 550 °C. Here, these biochars are subjected to aqueous extraction followed by liquid chromatography organic carbon detection (LC-OCD) and thermal desorption gas chromatography mass spectrometry (TD-GC/MS). These techniques provide a structural insight into their more bio-available organic compounds and how they vary with pyrolysis temperature. In comparison to neat biochar, their mineral-enhanced composites produce at least three times the water-extractable organic carbon, nitrogen and VOCs, and this increase is further amplified at pyrolysis higher temperatures. However, the biochar carbon fraction that is mobile is low, with total TD-GC/MS compatible VOCs reporting approximately 0.2% and LC-OCD solubles approximately 1–2%. Prior mineral impregnation of bamboo enhances the release of oxygenated compounds including humics and phenolics from its biochars. This increase in mobile oxygenates occurs at higher pyrolysis temperatures despite these minerals catalyzing lignocellulose condensation and carbonization. This anomaly is explained by oxygenates relatively small contribution and the self inerting batch pyrolysis conditions producing different biochar surface and bulk molecular properties. By describing the impact of mineral amendments on the yield and structure of mobile organic compounds that may be released from biochar, this work contributes to our understanding of biochar efficacy in soils

    Does publication bias inflate the apparent efficacy of psychological treatment for major depressive disorder? A systematic review and meta-analysis of US national institutes of health-funded trials

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    Background The efficacy of antidepressant medication has been shown empirically to be overestimated due to publication bias, but this has only been inferred statistically with regard to psychological treatment for depression. We assessed directly the extent of study publication bias in trials examining the efficacy of psychological treatment for depression. Methods and Findings We identified US National Institutes of Health grants awarded to fund randomized clinical trials comparing psychological treatment to control conditions or other treatments in patients diagnosed with major depressive disorder for the period 1972–2008, and we determined whether those grants led to publications. For studies that were not published, data were requested from investigators and included in the meta-analyses. Thirteen (23.6%) of the 55 funded grants that began trials did not result in publications, and two others never started. Among comparisons to control conditions, adding unpublished studies (Hedges’ g = 0.20; CI95% -0.11~0.51; k = 6) to published studies (g = 0.52; 0.37~0.68; k = 20) reduced the psychotherapy effect size point estimate (g = 0.39; 0.08~0.70) by 25%. Moreover, these findings may overestimate the "true" effect of psychological treatment for depression as outcome reporting bias could not be examined quantitatively. Conclusion The efficacy of psychological interventions for depression has been overestimated in the published literature, just as it has been for pharmacotherapy. Both are efficacious but not to the extent that the published literature would suggest. Funding agencies and journals should archive both original protocols and raw data from treatment trials to allow the detection and correction of outcome reporting bias. Clinicians, guidelines developers, and decision makers should be aware that the published literature overestimates the effects of the predominant treatments for depression

    Immunohistochemical detection and regulation of α5 nicotinic acetylcholine receptor (nAChR) subunits by FoxA2 during mouse lung organogenesis

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    <p>Abstract</p> <p>Background</p> <p>α<sub>5 </sub>nicotinic acetylcholine receptor (nAChR) subunits structurally stabilize functional nAChRs in many non-neuronal tissue types. The expression of α<sub>5 </sub>nAChR subunits and cell-specific markers were assessed during lung morphogenesis by co-localizing immunohistochemistry from embryonic day (E) 13.5 to post natal day (PN) 20. Transcriptional control of α<sub>5 </sub>nAChR expression by FoxA2 and GATA-6 was determined by reporter gene assays.</p> <p>Results</p> <p>Steady expression of α<sub>5 </sub>nAChR subunits was observed in distal lung epithelial cells during development while proximal lung expression significantly alternates between abundant prenatal expression, absence at PN4 and PN10, and a return to intense expression at PN20. α<sub>5 </sub>expression was most abundant on luminal edges of alveolar type (AT) I and ATII cells, non-ciliated Clara cells, and ciliated cells in the proximal lung at various periods of lung formation. Expression of α<sub>5 </sub>nAChR subunits correlated with cell differentiation and reporter gene assays suggest expression of α<sub>5 </sub>is regulated in part by FoxA2, with possible cooperation by GATA-6.</p> <p>Conclusions</p> <p>Our data reveal a highly regulated temporal-spatial pattern of α<sub>5 </sub>nAChR subunit expression during important periods of lung morphogenesis. Due to specific regulation by FoxA2 and distinct identification of α<sub>5 </sub>in alveolar epithelium and Clara cells, future studies may identify possible mechanisms of cell differentiation and lung homeostasis mediated at least in part by α<sub>5</sub>-containing nAChRs.</p

    Signatures of a globally optimal searching strategy in the three-dimensional foraging flights of bumblebees

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    Simulated annealing is a powerful stochastic search algorithm for locating a global maximum that is hidden among many poorer local maxima in a search space. It is frequently implemented in computers working on complex optimization problems but until now has not been directly observed in nature as a searching strategy adopted by foraging animals. We analysed high-speed video recordings of the three-dimensional searching flights of bumblebees (Bombus terrestris) made in the presence of large or small artificial flowers within a 0.5 m3 enclosed arena. Analyses of the three-dimensional flight patterns in both conditions reveal signatures of simulated annealing searches. After leaving a flower, bees tend to scan back-and forth past that flower before making prospecting flights (loops), whose length increases over time. The search pattern becomes gradually more expansive and culminates when another rewarding flower is found. Bees then scan back and forth in the vicinity of the newly discovered flower and the process repeats. This looping search pattern, in which flight step lengths are typically power-law distributed, provides a relatively simple yet highly efficient strategy for pollinators such as bees to find best quality resources in complex environments made of multiple ephemeral feeding sites with nutritionally variable rewards

    Incident Tuberculosis during Antiretroviral Therapy Contributes to Suboptimal Immune Reconstitution in a Large Urban HIV Clinic in Sub-Saharan Africa

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    Antiretroviral therapy (ART) effectively decreases tuberculosis (TB) incidence long-term, but is associated with high TB incidence rates in the first 6 months. We sought to determine the incidence and the long-term effects of TB during ART on HIV treatment outcome, and the risk factors for incident TB during ART in a large urban HIV clinic in Uganda.Routinely collected longitudinal clinical data from all patients initiated on first-line ART was retrospectively analysed. 5,982 patients were included with a median baseline CD4+ T cell count (CD4 count) of 117 cells/mm(3) (interquartile range [IQR]; 42, 182). In the first 2 years, there were 336 (5.6%) incident TB events in 10,710 person-years (py) of follow-up (3.14 cases/100 pyar [95% CI 2.82-3.49]); incidence rates at 0-3, 3-6, 6-12 and 12-24 months were 11.25 (9.58-13.21), 6.27 (4.99-7.87), 2.47 (1.87-3.36) and 1.02 (0.80-1.31), respectively. Incident TB during ART was independently associated with baseline CD4 count of <50 cells/mm(3) (hazard ratio [HR] 1.84 [1.25-2.70], P = 0.002) and male gender (HR 1.68 [1.34-2.11], P<0.001). After two years on ART, the patients who had developed TB in the first 12 months had a significantly lower median CD4 count increase (184 cells/mm(3) [IQR; 107, 258, n = 118] vs 209 cells/mm(3) [124, 309, n = 2166], P = 0.01), a larger proportion of suboptimal immune reconstitution according to two definitions (increase in CD4 count <200 cells/mm(3): 57.4% vs 46.9%, P = 0.03, and absolute CD4 count <200 cells/mm(3): 30.4 vs 19.9%, P = 0.006), and a higher percentage of immunological failure according to the WHO criteria (13.6% vs 6.5%, P = 0.003). Incident TB during ART was independently associated with poor CD4 count recovery and fulfilling WHO immunological failure definitions.Incident TB during ART occurs most often within 3 months and in patients with CD4 counts less than 50 cells/mm(3). Incident TB during ART is associated with long-term impairment in immune recovery

    HIV Prevention in Care and Treatment Settings: Baseline Risk Behaviors among HIV Patients in Kenya, Namibia, and Tanzania.

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    HIV care and treatment settings provide an opportunity to reach people living with HIV/AIDS (PLHIV) with prevention messages and services. Population-based surveys in sub-Saharan Africa have identified HIV risk behaviors among PLHIV, yet data are limited regarding HIV risk behaviors of PLHIV in clinical care. This paper describes the baseline sociodemographic, HIV transmission risk behaviors, and clinical data of a study evaluating an HIV prevention intervention package for HIV care and treatment clinics in Africa. The study was a longitudinal group-randomized trial in 9 intervention clinics and 9 comparison clinics in Kenya, Namibia, and Tanzania (N = 3538). Baseline participants were mostly female, married, had less than a primary education, and were relatively recently diagnosed with HIV. Fifty-two percent of participants had a partner of negative or unknown status, 24% were not using condoms consistently, and 11% reported STI symptoms in the last 6 months. There were differences in demographic and HIV transmission risk variables by country, indicating the need to consider local context in designing studies and using caution when generalizing findings across African countries. Baseline data from this study indicate that participants were often engaging in HIV transmission risk behaviors, which supports the need for prevention with PLHIV (PwP). TRIAL REGISTRATION: ClinicalTrials.gov NCT01256463

    Ciliated Epithelial Cell Differentiation at Air-Liquid Interface Using Commercially Available Culture Media

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    The human nasal epithelium contains basal stem/progenitor cells that produce differentiated multiciliated and mucosecretory progeny. Basal epithelial cells can be expanded in cell culture and instructed to differentiate at an air-liquid interface using transwell membranes and differentiation media. For basal cell expansion, we have used 3T3-J2 co-culture in epithelial culture medium containing EGF, insulin, and a RHO-associated protein kinase (ROCK) inhibitor, Y-27632 (3T3 + Y). Here we describe our protocols for ciliated differentiation of these cultures at air-liquid interface and compare four commercially available differentiation media, across nine donor cell cultures (six healthy, two patients with chronic obstructive pulmonary disease (COPD), and one with primary ciliary dyskinesia (PCD)). Bright-field and immunofluorescence imaging suggested broad similarity between differentiation protocols. Subtle differences were seen in transepithelial electrical resistance (TEER), ciliary beat frequency, mucus production, and the extent to which basal cells are retained in differentiated cultures. Overall, the specific differentiation medium used in our air-liquid interface culture protocol was not a major determinant of ciliation, and our data suggest that the differentiation potential of basal cells at the outset is a more critical factor in air-liquid interface culture outcome. Detailed information on the constituents of the differentiation media was only available from one of the four manufacturers, a factor that may have profound implications in the interpretation of some research studies

    Water dispersible microbicidal cellulose acetate phthalate film

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    BACKGROUND: Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. METHODS: CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. RESULTS: The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. CONCLUSIONS: Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP
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