Sessile rotifers (Rotifera) exhibit strong seasonality in a shallow,eutrophic Ramsar site in Mexico

To better understand the sessile rotifer community of a shallow, eutrophic lake, we monitored over a 1‐year period the monthly changes in the density and diversity of rotifers on the roots of the common water hyacinth, Eichhornia crassipes, which served as a representative hydrophyte. Selected physical and chemical parameters of the water were also determined. Mean annual density of all sessile species was 630 individuals per ml. Species of Collothecacea (n = 7) were most abundant. Of the 12 species of Flosculariaceae (Flosculariidae), Sinantherina socialis occurred seasonally, while Ptygura beauchampi was most common across all seasons. The Shannon–Wiener diversity index was highest (H′ = 2.8) in April, but decreased in January (H′ = 1.3). Applying the concept of the guild ratio (functional‐based analysis) we found that raptorial species (Collothecacea) were dominant over most of the year (June–February), while microphagous Flosculariidae were dominant during the warm, drier season (March–May). BEST (optimal matching of biota to environment, including stepwise search) analysis and canonical correspondence revealed that temperature, dissolved oxygen, pH, turbidity, and transparency strongly influenced sessile rotifer dynamics. We also found significant correlations between the density of some species and physicochemical variables. These species included Collotheca ambigua, C. coronetta, C. ornata, C. campanulata, C. tenuilobata, and Stephanoceros millsii in the Collothecacea; and Beauchampia crucigere, Limnias melicerta, L. ceratophylli, Ptygura crystallina, P. melicerta, and Sinantherina ariprepes in the Flosculariidae. Our study shows that the communities of sessile rotifers were structured by abiotic factors and that the guild ratio is useful for understanding the relationship between sessile rotifers and their substrata.     

Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis

Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North‐central Arizona, USA. Methods: We sampled 75 0.05‐ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive effect of richness on plant cover. Richness was strongly related to soil nitrogen in the model, with evidence for both a direct negative effect and an indirect non‐linear relationship mediated through understory plant cover. Soil organic matter appeared to have a positive influence on understory richness that was independent of soil nitrogen. Richness was lowest where the forest overstory was densest, which can be explained through indirect effects on soil organic matter, soil nitrogen and understory cover. Finally, model results suggest a variety of direct and indirect processes whereby mineral soil properties can influence richness. Conclusions: Understory plant species richness and plant cover in P. ponderosa forests appear to be significantly influenced by soil organic matter and nitrogen, which are, in turn, related to overstory density and composition and mineral soil properties. Thus, soil properties can impose direct and indirect constraints on local species diversity in ponderosa pine forests.     

Product quality research institute evaluation of cascade impactor profiles of pharmaceutical aerosols, part 3: Final report on a statistical procedure for determining equivalence

The purpose of this article is to report final results of the evaluation of a chi-square ratio test proposed by the US Food and Drug Administration (FDA) for demonstrating equivalence of aerodynamic particle size distribution (APSD) profiles of nasal and orally inhaled drug products. A working group of the Product Quality Research Institute previously published results demonstrating some limitations of the proposed test. In an effort to overcome the test's limited discrimination, the group proposed a supplemental test, a population bioequivalence (PBE) test for impactor-sized mass (ISM). In this final report the group compares the chi-square ratio test to the ISM-PBE test and to the combination of both tests. The basis for comparison is a set of 55 realistic scenarios of cascade impactor data, which were evaluated for equivalence by the statistical tests and independently by the group members. In many instances, the combined application of these 2 tests appeared to increase the discriminating ability of the statistical procedure compared with the chi-square ratio test alone. In certain situations the chi-square ratio test alone was sufficient to determine equivalence of APSD profiles, while in other situations neither of the tests alone nor their combination was adequate. This report describes all of these scenarios and results. In the end, the group did not recommend a statistical test for APSD profile equivalence. The group did not investigate other in vitro tests, in vivo issues, or other statistical tests for APSD profile comparisons. The studied tests are not intended for routine quality control of APSD.     

Effect of a blend of essential oil compounds on the colonization of starch-rich substrates by bacteria in the rumen

AIMS: To investigate the mode of action of a blend of essential oil compounds on the colonization of starch-rich substrates by rumen bacteria. METHODS AND RESULTS: Starch-rich substrates were incubated, in nylon bags, in the rumen of sheep organized in a 4 x 4 latin square design and receiving a 60:40 silage : concentrate diet. The concentrate was either high or low in crude protein, and the diet was supplemented or not with a commercial blend of essential oil compounds (110 mg per day). The total genomic DNA was extracted from the residues in the bags. The total eubacterial DNA was quantified by real-time PCR and the proportion of Ruminobacter amylophilus, Streptococcus bovis and Prevotella bryantii was determined. Neither the supplementation with essential oil compounds nor the amount of crude protein affected the colonization of the substrates by the bacteria quantified. However, colonization was significantly affected by the substrate colonized. CONCLUSIONS: The effect of essential oils on the colonization of starch-rich substrates is not mediated through the selective inhibition of R. amylophilus. SIGNIFICANCE AND IMPACT OF THE STUDY: This study enhances our understanding of the colonization of starch-rich substrates, as well as of the mode of action of the essential oils as rumen manipulating agents.     

Recent Progress in Flexible Electrochemical Capacitors: Electrode Materials,Device Configuration,and Functions

With increasing demand for portable, flexible, and even wearable electronic devices, flexible energy storage systems have received increasing attention as a key component in this emerging field. Among the options, supercapacitors, commonly referred to as ultracapacitors or electrochemical capacitors, are widely recognized as a potential energy storage system due to their high power, fast charge/discharge rate, long cycling life‐time, and low cost. To date, considerable effort has been dedicated to developing high‐performance flexible supercapacitors based on various electrode materials; including carbon nanomaterials (e.g., carbon nanotubes, graphene, porous carbon materials, carbon paper, and textile), conducting polymers (e.g., polyaniline, polypyrrole, polythiophene), and hybrid materials. A brief introduction to the field is provided and the state‐of‐the‐art is reviewed with special emphasis on electrode materials and device configurations.     

Hit-to-Lead studies: the discovery of potent, orally bioavailable thiazolopyrimidine CXCR2 receptor antagonists

A Hit-to-Lead optimisation programme was carried out on a high throughput screening hit, the thiazolopyrimidine 1, resulting in the discovery of the potent, orally bioavailable CXCR2 antagonist 29.