Abstract
Planetary obliquity and eccentricity influence climate by shaping the spatial and temporal patterns of stellar energy incident at a planet’s surface, affecting both the annual mean climate ...and magnitude of seasonal variability. Previous work has demonstrated the importance of both planetary obliquity and eccentricity for climate and habitability, but most studies have not explicitly modeled the response of life to these parameters. While exaggerated seasons may be stressful to some types of life, a recent study found an increase in marine biological activity for moderately high obliquities <45° assuming an Earth-like eccentricity. However, it is unclear how life might respond to obliquities >45°, eccentricities much larger than Earth’s, or the combination of both. To address this gap, we use cGENIE-PlaSim, a 3D marine biogeochemical model coupled to an atmospheric general circulation model, to investigate the response of Earth-like marine life to a large range of obliquities (0°–90°) and eccentricities (0–0.4). We find that marine biological activity increases with both increasing obliquity and eccentricity across the parameter space we considered, including the combination of high obliquity and high eccentricity. We discuss these results in the context of remote biosignatures, and we argue that planets with high obliquity and/or eccentricity may be superhabitable worlds that are particularly favorable for exoplanet life detection.
This study compared the efficacy of chlorine (20–200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20–200 ppm chlorite ion concentration, Sanova
®), and ...aqueous chlorine dioxide (20–200 ppm chlorite ion concentration, TriNova
®) washes in reducing populations of
Escherichia coli O157:H7 on artificially inoculated lettuce. Fresh-cut leaves of Romaine or Iceberg lettuce were inoculated by immersion in water containing
E. coli O157:H7 (8 log CFU/ml) for 5 min and dried in a salad spinner. Leaves (25 g) were then washed for 2 min, immediately or following 24 h of storage at 4 °C. The washing treatments containing chlorite ion concentrations of 100 and 200 ppm were the most effective against
E. coli O157:H7 populations on Iceberg lettuce, with log reductions as high as 1.25 log CFU/g and 1.05 log CFU/g for TriNova
® and Sanova
® wash treatments, respectively. All other wash treatments resulted in population reductions of less than 1 log CFU/g. Chlorine (200 ppm), TriNova
®, Sanova
®, and acidic electrolyzed water were all equally effective against
E. coli O157:H7 on Romaine, with log reductions of ~
1 log CFU/g. The 20 ppm chlorine wash was as effective as the deionized water wash in reducing populations of
E. coli O157:H7 on Romaine and Iceberg lettuce. Scanning electron microscopy indicated that
E. coli O157:H7 that was incorporated into biofilms or located in damage lettuce tissue remained on the lettuce leaf, while individual cells on undamaged leaf surfaces were more likely to be washed away.
In the midst of an ongoing biodiversity crisis, much research has focused on species losses and their impacts on ecosystem functioning. The functional consequences (ecosystem response) of shifts in ...communities are shaped not only by changes in species richness, but also by compositional shifts that result from species losses and gains. Species differ in their contribution to ecosystem functioning, so species identity underlies the consequences of species losses and gains on ecosystem functions. Such research is critical to better predict the impact of disturbances on communities and ecosystems. We used the “Community Assembly and the Functioning of Ecosystems” (CAFE) approach, a modification of the Price equation to understand the functional consequences and relative effects of richness and composition changes in small nonvolant mammal and dung beetle communities as a result of two common disturbances in North American prairie restorations, prescribed fire and the reintroduction of large grazing mammals. Previous research in this system has shown dung beetles are critically important decomposers, while small mammals modulate much energy in prairie food webs. We found that dung beetle communities were more responsive to bison reintroduction and prescribed fires than small nonvolant mammals. Dung beetle richness increased after bison reintroduction, with higher dung beetle community biomass resulting from changes in remaining species (context‐dependent component) rather than species turnover (richness components); prescribed fire caused a minor increase in dung beetle biomass for the same reason. For small mammals, bison reintroduction reduced energy transfer through the loss of species, while prescribed fire had little impact on either small mammal richness or energy transfer. The CAFE approach demonstrates how bison reintroduction controls small nonvolant mammal communities by increasing prairie food web complexity, and increases dung beetle populations with possible benefits for soil health through dung mineralization and soil bioturbation. Prescribed fires, however, have little effect on small mammals and dung beetles, suggesting a resilience to fire. These findings illustrate the key role of re‐establishing historical disturbance regimes when restoring endangered prairie ecosystems and their ecological function.
Acetaminophen (APAP) toxicity in primary mouse hepatocytes occurs in two phases. The initial phase (0−2 h) occurs with metabolism to N-acetyl-p-benzoquinoneimine which depletes glutathione, and ...covalently binds to proteins, but little toxicity is observed. Subsequent washing of hepatocytes to remove APAP and reincubating in media alone (2−5 h) results in toxicity. We previously reported that the reincubation phase occurs with mitochondrial permeability transition (MPT) and increased oxidative stress (dichlorodihydrofluorescein fluorescence) (DCFH2). Since DCFH2 may be oxidized by multiple oxidative mechanisms, we investigated the role of reactive nitrogen species (RNS) leading to 3-nitrotyrosine in proteins by ELISA and by immunoblots. Incubation of APAP with hepatocytes for 2 h did not result in toxicity or protein nitration; however, washing hepatocytes and reincubating in media alone (2−5 h) resulted in protein nitration which correlated with toxicity. Inclusion of the MPT inhibitor, cyclosporine A, in the reincubation media eliminated toxicity and protein nitration. The general nitric oxide synthase (NOS) inhibitor L-NMMA and the neuronal NOS (NOS1) inhibitor, 7-nitroindazole, added in the reincubation media decreased toxicity and protein nitration; however, neither the inducible NOS (NOS2) inhibitors L-NIL (N6-(1-iminoethyl)-l-lysine) nor SAIT (S-(2-aminoethyl)isothiourea) decreased protein nitration or toxicity. The RNS scavengers, N-acetylcysteine, and high concentrations of APAP, added in the reincubation phase decreased toxicity and protein nitration. 7-Nitroindazole and cyclosporine A inhibited the APAP-induced loss of mitochondrial membrane potential when added in the reincubation phase. The data indicate a role for RNS in APAP induced toxicity.
Non-hominid primates (NHPs) are some of the most understudied invasive mammals in terms of their impacts to biodiversity and the ability to successfully manage them, despite their having been ...implicated in numerous extinctions. We found 99 NHP populations of 37 species have been introduced on at least 67 islands and various mainland locations. NHPs have been implicated in at least 69 extinctions or extirpations. NHPs reduce human food security, display aggressive behavior sometimes resulting in human fatalities, and transmit diseases. We identified thirty islands where management is likely feasible and rank them by the potential biodiversity benefits of NHP management. At least eight attempts to eradicate NHP populations have been made with only one so far having been successful. Social considerations along with technological advancements in management methods are both needed to curb the impacts of NHPs and protect people and biodiversity on islands invaded by NHPs.
Purpose:
The use of cyanoacrylate for intravenous catheter securement is of interest to clinicians and patients, because of the superior adhesive strength and hemostatic effect of cyanoacrylate ...compared to current securement devices. The purpose of this study is to use novel in vitro and in vivo testing methods to analyze the hemostatic effect of a catheter securement cyanoacrylate (cyanoacrylate).
Methods:
An unprecedented in vitro method was performed to determine the effects of a cyanoacrylate on a customized modified activated clotting time assay and blood flow inhibition assay by exposing blood or plasma to either one or three drops of cyanoacrylate. For the in vivo testing, full-thickness incisions were made on swine, and the bleeding was scored prior to treatment and at 3, 6, 9, and 12 min after treatment.
Results:
The cyanoacrylate rapidly achieved hemostasis in the presence of anticoagulated whole blood, platelet-poor plasma, and non-anticoagulated whole blood, in vitro. The cyanoacrylate achieved hemostasis 12-fold faster than thromboplastin in the modified activated clotting time assay. The cyanoacrylate does not alter normal blood clotting, as measured by prothrombin time. In vivo, the bleeding score of cyanoacrylate prior to treatment and at 3, 6, 9, and 12 min after treatment were 2.3 ± 1.0, 0.3 ± 0.5, 0.2 ± 0.5, 0.2 ± 0.4, and 0.2 ± 0.4, respectively.
Conclusion:
This study indicates that cyanoacrylate demonstrates a potent mechanical hemostatic effect and cyanoacrylate in the presence of anticoagulated whole blood has an activated clotting time that is 12 times quicker than thromboplastin. The cyanoacrylate was found to be significantly equivalent to two known hemostatic agents, in vivo.
Fresh produce, such as blueberries, continues to be a source of foodborne illness in the United States. Despite new practices and intervention technologies, blueberries and other produce are ...contaminated with foodborne pathogens, such as Salmonella. The aim of this study was to evaluate the efficacy of chlorine dioxide gas (CDG) against Salmonella enterica serovars Newport, Stanley, Muenchen, and Anatum on artificially contaminated whole fresh blueberries. Blueberries were dip inoculated into a 400-mL bath containing a Salmonella serovar cocktail of either ca. 6 or 9 log CFU/mL. Samples were dried for either 2 or 24 h before treatment with 1.5 or 3 mg of CDG/L of air to a final treatment of 3.55 to 6 ppm/h/g of blueberry. Salmonella cells were recovered by stomaching CDG-treated and nontreated control samples with 0.1% peptone and enumerated on xylose lysine Tergitol 4 agar. CDG treatments achieved up to a 5.63-log CFU/g reduction of the cocktail using 5.5 ppm/h/g, whereas the lowest treatment, 4 ppm/h/g (1.5 mg of CDG/L), was still capable of a 4.45-log CFU/g reduction. Incubation time significantly (P < 0.001) affected CDG efficacy against both inoculation concentrations. Additionally, all serovars responded similarly to CDG treatment when tested individually (P > 0.0691). Finally, the availability of a water reservoir during treatments did not have a significant effect (P = 0.9818) on CDG efficacy in this study. Our results demonstrate that CDG can be an efficacious treatment option for whole blueberry decontamination.
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