Anaerobic Fermentation of Food Waste and Glycerol to Hydrogen

ABSTRACT Anaerobic Fermentation of Food Waste and Glycerol to Hydrogen Eric Krikorian Hydrogen has several well-known advantages as a fuel and chemical feedstock, but current methods of hydrogen production are costly and energy intensive. A potentially advantageous source of hydrogen is fermentation of organic wastes, especially any abundant, low-cost wastes with a high content of simple sugars. Molar hydrogen yields from fermenters (aka digesters) are affected by pH, organic loading rate (OLR), hydraulic residence time (HRT), and substrate type. A less studied process to increase yield is sparging with low-H2 content gas to strip H2 from the digester liquid. The present study optimized the levels of each of these variables for hydrogen production from glycerol and food waste, building on previous proof-of-concept studies that used glucose as the substrate. Six bench-scale, semi-continuously fed, stirred, anaerobic digesters were constructed and fed glycerol or food waste as a substrate. In a series of experiments, pH, HRT, OLR, and gas sparging rate were tested over a range of values. pH levels were controlled by use of phosphate buffers. In an envisioned process, low-H2 content from a second-stage methane digester would be used as the sparging gas, allowing subsequent combustion of a high-H2 content biogas with low NOx formation potential. N2 was used as a surrogate for biogas in one set of experiments. The main conclusions are based on data from periods of steady-state digester performance and daily measurements of pH, alkalinity, biogas production, biogas composition, total and volatile suspended solids, and chemical oxygen demand (COD). COD balances were measured for all experiments and generally showed recoveries of \u3e85%. With glycerol substrate, the highest molar hydrogen yield (0.071 ± 0.0100 mol H2/mol glycerol) and volumetric hydrogen production (0.281 ± 0.0395 LH2/LReactor-day) were achieved with the following: pH 6.51, OLR 18.8 g COD/L-day, HRT 12 hours, and sparging rate of 3.2 mL/min, and 1-L working volume. Gas type (N2 or biogas) used in sparging did not influence hydrogen production. The best results with food waste (0.021 ± 0.0013 mol H2/mol COD and 0.478 ± 0.0280 L H2/LReactor-day) were obtained with the following conditions: OLR 33.9 g COD/L-day and nitrogen sparging rate of 1.0 L N2/hour, and 1-L working volume. pH and HRT were not optimized for food waste substrate, but the best values from the glycerol experiments were adopted. Sparged glycerol and food waste digesters had molar hydrogen yields at least 40% greater than controls. Nonetheless, molar hydrogen yields in the present study were lower than in those reported by other authors, for unknown reasons. Yields from food waste might be improved by optimizing pH and HRT levels. Alkalinity sources need to be identified to replace the non-scalable phosphate buffers of the present research. Lastly, long-term experiments should consider whether attached growth of hydrogen-consuming methanogens develops in hydrogen fermentation reactors

Improved metabolic function and cognitive performance in middle-aged adults following a single dose of wild blueberry

Purpose: Research has demonstrated cognitive benefits following acute polyphenol-rich berry consumption in children and young adults. Berry intake also has been associated with metabolic benefits. No study has yet examined cognitive performance in middle-aged adults. We investigated the relationships among cognitive and metabolic outcomes in middle-aged adults following wild blueberry (WBB) consumption. Methods: Thirty-five individuals aged 40 to 65 years participated in a randomized, double blind, cross-over study. Participants consumed a breakfast meal and 1-cup equivalent WBB drink or matched placebo beverage on two occasions. Participants completed cognitive tasks and had blood drawn before and at regular intervals for 8 h after each meal/treatment. Changes in episodic memory and executive function (EF) were assessed alongside plasma levels of glucose, insulin, and triglyceride. Results: Analysis of the memory related Auditory Verbal Learning Task (AVLT) word recognition measure revealed a decrease in performance over the test day after placebo intake, whereas performance after WBB was maintained. For the AVLT word rejection measure, participants identified more foils following WBB in comparison to placebo. Benefits were also observed for EF on the Go-NoGo task with fewer errors following WBB intake on cognitively demanding invalid NoGo trials in comparison to placebo. Furthermore, in comparison to placebo, response times were faster for the Go-NoGo task, specifically at 4h and 8h following WBB treatment. We also observed reduced post meal glucose and insulin, but not triglyceride, concentrations in comparison to placebo over the first 2h following ingestion. Though the addition of Age, BMI, glucose and insulin as covariates to the analysis reduced the significant effect of beverage for AVLT word rejection, metabolic outcomes did not interact with treatment to predict cognitive performance with the exception of one isolated trend. Conclusions: This study indicated acute cognitive benefits of WBB intake in cognitively healthy middle-aged individuals, particularly in the context of demanding tasks and cognitive fatigue. WBB improved glucose and insulin responses to a meal. Further research is required to elucidate the underlying mechanism by which WBB improves cognitive function

Recent Research on the Health Benefits of Blueberries and Their Anthocyanins

Awareness of the human health benefits of blueberries is underpinned by a growing body of positive scientific evidence from human observational and clinical research, plus mechanistic research using animal and in vitro models. Blueberries contain a large number of phytochemicals, including abundant anthocyanin pigments. Of their various phytochemicals, anthocyanins probably make the greatest impact on blueberry health functionality. Epidemiological studies associate regular, moderate intake of blueberries and/or anthocyanins with reduced risk of cardiovascular disease, death, and type 2 diabetes, and with improved weight maintenance and neuroprotection. These findings are supported by biomarker-based evidence from human clinical studies. Among the more important healthful aspects of blueberries are their anti-inflammatory and antioxidant actions and their beneficial effects on vascular and glucoregulatory function. Blueberry phytochemicals may affect gastrointestinal microflora and contribute to host health. These aspects have implications in degenerative diseases and conditions as well as the aging process. More evidence, and particularly human clinical evidence, is needed to better understand the potential for anthocyanin-rich blueberries to benefit public health. However, it is widely agreed that the regular consumption of tasty, ripe blueberries can be unconditionally recommended

Microfilaments and actin-associated proteins at sites of membrane-substrate attachment within acetylcholine receptor clusters

Rat myotubes in tissue culture form broad areas of close contact with the substrate. These areas often display two distinct, interdigitating sets of membrane domains. One, the "contact domain", is close to the substrate; the other, termed the "AChR domain", is further from the substrate and is rich in acetylcholine receptors (AChR). We have used fluorescence techniques to study the organization of the cytoskeleton in these areas. Substrate-apposed membrane of the myotubes was exposed either by shearing or by permeabilizing the cells with a neutral detergent. Phalloidin derivatives and affinity-purified polyclonal or monoclonal antibodies specific for cytoskeletal proteins were then applied to the samples. Sheared samples were observed by epifluorescence microscopy; detergent-permeabilized samples were observed by total internal reflection fluorescence microscopy. We found that, like antivinculin, fluorescent phalloidin derivatives and antibodies to [alpha]-actinin, filamin, and talin preferentially labeled the contact domains. This suggests that bundles of microfilaments associate with the membrane at sites of myotubesubstrate attachment. In contrast, a 43K protein, closely associated with AChR, was present only at AChR domains. A monoclonal antibody to actin labeled both AChR and contact domains, suggesting that actin is enriched over both regions. Our results suggest that, like the plasma membrane of AChR clusters, the underlying membrane skeleton is organized into at least two distinct domains.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27926/1/0000350.pd

Conflicts and Agreements: Canada’s Foundations and Their Consequences, 1865-1949

Archived with permission. Copyright © the panelists/editor, 2017.In response to curiosity about Confederation during this sesquicentennial year, historians Patrice Dutil, Daniel Heidt, P. Whitney Lackenbauer, Marcel Martel, Robert Wardhaugh, and political scientist Jacqueline Krikorian convened at the University of Waterloo for a public panel to review Canada’s expansion, strengths, and faults during the past 150 years. Everyone was impressed by the ensuing 1.5 hours of discussions, so the Centre on Foreign Policy and Federalism agreed to commission a publication of the proceedings in written form, and post it to the web before 1 July so that more Canadians would have the opportunity to consider the event’s varied opinions for Canada 150.Crabtree Foundation University of Waterloo Library Social Sciences and Humanities Research Council St. Jerome’s University Centre on Foreign Policy and Federalis

Alzheimer's “Prevention” vs. “Risk Reduction”: Transcending Semantics for Clinical Practice

The terms “prevention” and “risk reduction” are often used interchangeably in medicine. There is considerable debate, however, over the use of these terms in describing interventions that aim to preserve cognitive health and/or delay disease progression of Alzheimer's disease (AD) for patients seeking clinical care. Furthermore, it is important to distinguish between Alzheimer's disease prevention and Alzheimer's dementia prevention when using these terms. While prior studies have codified research-based criteria for the progressive stages of AD, there are no clear clinical consensus criteria to guide the use of these terms for physicians in practice. A clear understanding of the implications of each term will help guide clinical practice and clinical research. The authors explore the semantics and appropriate use of the terms “prevention” and “risk reduction” as they relate to AD in clinical practice

Nutrition for the ageing brain: towards evidence for an optimal diet

As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline