Rheagogies: modelling non-trophic effects in food webs

In a food web, nutrients flow via trophic links. For this reason, trophic interactions have a fundamental character due to the principle of mass conservation. To further comply with this principle, we consider a food web model that includes nutrient cycling. Non-trophic effects amongst species of the food web are modelled as interaction modifications, i.e., a functional change in the trophic interaction between two species caused by a third species (a three-party interaction that we call ‘‘rheagogy’’).We also consider that the ecological communities modelled by the food webs result from an assembly process that involves colonisations and extinctions. We find that two distinct classes of ecological communities must be distinguished: (a) ‘‘superefficient’’ communities, in which almost all available nutrients are incorporated into the biomass and (b) ‘‘sub-efficient’’ ones, in which a large proportion of nutrients is not fixed by living organisms. We show that rheagogies (that model non-trophic interactions) are crucial: the larger the effects of rheagogies, the easier the construction of super-efficient communities. These communities are characterized by positive rheagogies, meaning that a certain proportion of mutualistic interactions is necessary. Systems with few or weak rheagogies are less likely to use available abiotic resources efficiently. Although richness (i.e., number of species) is also positively related to efficient nutrient use, its importance is much smaller than that of rheagogies

Loss of testosterone impairs anti-tumor neutrophil function.

In men, the incidence of melanoma rises rapidly after age 50, and nearly two thirds of melanoma deaths are male. The immune system is known to play a key role in controlling the growth and spread of malignancies, but whether age- and sex-dependent changes in immune cell function account for this effect remains unknown. Here, we show that in castrated male mice, neutrophil maturation and function are impaired, leading to elevated metastatic burden in two models of melanoma. Replacement of testosterone effectively normalized the tumor burden in castrated male mice. Further, the aberrant neutrophil phenotype was also observed in prostate cancer patients receiving androgen deprivation therapy, highlighting the evolutionary conservation and clinical relevance of the phenotype. Taken together, these results provide a better understanding of the role of androgen signaling in neutrophil function and the impact of this biology on immune control of malignancies

Health status and quality of life in patients with diabetes in Switzerland.

We aimed to assess the health status and quality of life (QoL) of patients with diabetes and explore the associated factors in a French-speaking region of Switzerland. This cross-sectional study analyzed self-reported data from 585 patients with diabetes. We ran univariate and multivariate regressions analyses on health status (Physical and Mental Component Summary scores (PCS, MCS) of the SF-12) and diabetes-specific QoL (ADDQoL score). Mean PCS was 43.1±10.4 and mean MCS was 46.7±11.1. The overall ADDQoL score was -1.6±1.6; the life domains of the ADDQoL with the lowest scores were freedom to eat, sex life and freedom to drink. Being older was independently and significantly associated with higher mental health and QoL, while lower income was associated with lower physical health, mental health, and QoL. Having diabetes for over 10 years was associated with lower QoL, while insulin treatment and complications were correlated with lower physical health and QoL. This study provides key information on the health status and QoL of patients with diabetes in Switzerland and their associated factors, which can help healthcare providers to identify patients at higher risk of lower health and QoL

Illusory Increases in Font Size Improve Letter Recognition

Visual performance of human observers depends not only on the optics of the eye and early sensory encoding but also on subsequent cortical processing and representations. In two experiments, we demonstrated that motion adaptation can enhance as well as impair visual acuity. Observers who experienced an expanding motion aftereffect exhibited improved letter recognition, whereas observers who experienced a contracting motion aftereffect showed impaired letter recognition. We conclude that illusory enlargement and shrinkage of a visual stimulus can modulate visual acuity

Response of a Focused Transducer Facing a Rigid Reflector

Focused ultrasonic transducers can be useful in material characterization and tissue property measurement because of the improved signal to noise ratio as compared to flat transducers. To fully understand the transducer output, it is useful to know the system transfer function or impulse response of a focused transducer first acting as a transmitter and then receiving the signal reflected off a rigid plane. The resulting received pressure of a pulse-echo system can also be characterized in terms of a diffraction correction factor. The determination of the impulse response or diffraction correction factor is well understood for flat disk transducers, but is more complex for focused transducers

Toll-Like Receptor 2 Signaling Protects Mice from Tumor Development in a Mouse Model of Colitis-Induced Cancer

Inflammatory bowel disease (IBD) is a disorder of chronic inflammation with increased susceptibility to colorectal cancer. The etiology of IBD is unclear but thought to result from a dysregulated adaptive and innate immune response to microbial products in a genetically susceptible host. Toll-like receptor (TLR) signaling induced by intestinal commensal bacteria plays a crucial role in maintaining intestinal homeostasis, innate immunity and the enhancement of intestinal epithelial cell (IEC) integrity. However, the role of TLR2 in the development of colorectal cancer has not been studied. We utilized the AOM-DSS model for colitis-associated colorectal cancer (CAC) in wild type (WT) and TLR2−/− mice. Colons harvested from WT and TLR2−/− mice were used for histopathology, immunohistochemistry, immunofluorescence and cytokine analysis. Mice deficient in TLR2 developed significantly more and larger colorectal tumors than their WT controls. We provide evidence that colonic epithelium of TLR2−/− mice have altered immune responses and dysregulated proliferation under steady-state conditions and during colitis, which lead to inflammatory growth signals and predisposition to accelerated neoplastic growth. At the earliest time-points assessed, TLR2−/− colons exhibited a significant increase in aberrant crypt foci (ACF), resulting in tumors that developed earlier and grew larger. In addition, the intestinal microenvironment revealed significantly higher levels of IL-6 and IL-17A concomitant with increased phospho-STAT3 within ACF. These observations indicate that in colitis, TLR2 plays a protective role against the development of CAC

Improvements in vision-related quality of life in blind patients implanted with the Argus II Epiretinal Prosthesis

Background: The purpose of this analysis is to report the change in quality of life (QoL) after treatment with the Argus II Epiretinal Prosthesis in patients with end-stage retinitis pigmentosa. Methods: The Vision and Quality of Life Index (VisQoL) was used to assess changes in QoL dimensions and overall utility score in a prospective 30-patient single-arm clinical study. VisQoL is a multi-attribute instrument consisting of six dimensions (injury, life, roles, assistance, activity and friendship) that may be affected by visual impairment. Within each dimension, patients were divided into two groups based on how much their QoL was affected by their blindness at baseline (moderate/severe or minimal). Outcomes were compared within each dimension sub-group between baseline and the combined follow-up periods using the Friedman test. In addition, data from the six dimensions were combined into a single utility score, with baseline data compared to the combined follow-up periods. Results: Overall, 80 per cent of the patients reported difficulty in one or more dimensions preimplant. Composite VisQoL utility scores at follow-up showed no statistically significant change from baseline; however, in three of the six VisQoL dimensions (injury, life and roles), patients with baseline deficits showed significant and lasting improvement after implantation with Argus II. In two of the three remaining dimensions (assistance and activity), data trended toward an improvement. In the final VisQoL dimension (friendship), none of the patients reported baseline deficits, suggesting that patients had largely adjusted to this attribute. Conclusion: Patients whose vision negatively affected them with respect to three VisQoL dimensions (that is, getting injured, coping with the demands of their life and fulfilling their life roles) reported significant improvement in QoL after implantation of the Argus II retinal prosthesis. Furthermore, the benefit did not deteriorate at any point during the 36-month follow-up, suggesting a long-term, durable improvement