Microbial Fuel Cells and Microbial Ecology: Applications in Ruminant Health and Production Research

Microbial fuel cell (MFC) systems employ the catalytic activity of microbes to produce electricity from the oxidation of organic, and in some cases inorganic, substrates. MFC systems have been primarily explored for their use in bioremediation and bioenergy applications; however, these systems also offer a unique strategy for the cultivation of synergistic microbial communities. It has been hypothesized that the mechanism(s) of microbial electron transfer that enable electricity production in MFCs may be a cooperative strategy within mixed microbial consortia that is associated with, or is an alternative to, interspecies hydrogen (H2) transfer. Microbial fermentation processes and methanogenesis in ruminant animals are highly dependent on the consumption and production of H2in the rumen. Given the crucial role that H2 plays in ruminant digestion, it is desirable to understand the microbial relationships that control H2 partial pressures within the rumen; MFCs may serve as unique tools for studying this complex ecological system. Further, MFC systems offer a novel approach to studying biofilms that form under different redox conditions and may be applied to achieve a greater understanding of how microbial biofilms impact animal health. Here, we present a brief summary of the efforts made towards understanding rumen microbial ecology, microbial biofilms related to animal health, and how MFCs may be further applied in ruminant research

On symbolic RG factorization of quasi-birth-and-death processes

QBD process, RG factorization, Truncation methods, Retrial queues, 60J22, 60J27, 60K25,

The first 100 days of SARS-CoV-2 control in Vietnam

Background: One hundred days after SARS-CoV-2 was first reported in Vietnam on January 23rd, 270 cases were confirmed, with no deaths. We describe the control measures used by the Government and their relationship with imported and domestically-acquired case numbers, with the aim of identifying the measures associated with successful SARS-CoV-2 control. Methods: Clinical and demographic data on the first 270 SARS-CoV-2 infected cases and the timing and nature of Government control measures, including numbers of tests and quarantined individuals, were analysed. Apple and Google mobility data provided proxies for population movement. Serial intervals were calculated from 33 infector-infectee pairs and used to estimate the proportion of pre-symptomatic transmission events and time-varying reproduction numbers. Results: A national lockdown was implemented between April 1st and 22nd. Around 200 000 people were quarantined and 266 122 RT-PCR tests conducted. Population mobility decreased progressively before lockdown. 60% (163/270) of cases were imported; 43% (89/208) of resolved infections remained asymptomatic for the duration of infection. The serial interval was 3·24 days, and 27·5% (95% confidence interval, 15·7%-40·0%) of transmissions occurred pre-symptomatically. Limited transmission amounted to a maximum reproduction number of 1·15 (95% confidence interval, 0·37-2·36). No community transmission has been detected since April 15th. Conclusions: Vietnam has controlled SARS-CoV-2 spread through the early introduction of mass communication, meticulous contact-tracing with strict quarantine, and international travel restrictions. The value of these interventions is supported by the high proportion of asymptomatic and imported cases, and evidence for substantial pre-symptomatic transmission.</p

Dementia onset, incidence and risk in type 2 diabetes: a matched cohort study with the Fremantle Diabetes Study Phase I

Aims/hypothesis: The study aimed to assess the incidence, age of onset, survival and relative hazard of dementia in well-categorised community-based patients with type 2 diabetes compared with a matched cohort of individuals without diabetes. Methods: A longitudinal observational study was undertaken involving 1291 participants with type 2 diabetes from the Fremantle Diabetes Study and 5159 matched residents without documented diabetes. Linkage with health-related databases was used to detect incident dementia. Relative hazards were assessed using both cause-specific and subdistribution proportional hazards models. Results: During 13.8 ± 5.8 years of follow-up, incident dementia occurred in 13.9% and 12.4% of the groups of participants with and without diabetes, respectively (p = 0.15). With type 2 diabetes, the incidence of dementia was higher (incidence rate ratio [IRR] 1.28, 95% CI 1.08, 1.51), as was the competing risk of death (IRR 1.50, 95% CI 1.38, 1.64). The ages when dementia was first recorded and when death with dementia occurred were both earlier with diabetes, by 1.7 (95% CI 0.6, 2.9) and 2.3 (95% CI 1.1, 3.6) years, respectively (both p ≤ 0.004). Type 2 diabetes was associated with an adjusted subdistribution HR of 1.18 (95% CI 1.00, 1.39), and a cause-specific HR of 1.51 (95% CI 1.27, 1.78) for all-cause dementia. Conclusions/interpretation: Type 2 diabetes is associated with an increased incidence of dementia, and dementia onset occurs at a younger age. The relative hazards of both dementia and premature mortality are increased and, as a consequence, the increased risk of dementia in type 2 diabetes is not as marked as suggested by cause-specific HRs