Associations of Dietary Intake with the Intestinal Microbiota and Short-Chain Fatty Acids Among Young Adults with Type 1 Diabetes and Overweight or Obesity

Background: Diet, a key component of type 1 diabetes (T1D) management, modulates the intestinal microbiota and its metabolically active byproducts—including SCFA—through fermentation of dietary carbohydrates such as fiber. However, the diet–microbiome relationship remains largely unexplored in longstanding T1D. Objectives: We evaluated whether increased carbohydrate intake, including fiber, is associated with increased SCFA-producing gut microbes, SCFA, and intestinal microbial diversity among young adults with longstanding T1D and overweight or obesity. Methods: Young adult men and women with T1D for ≥1 y, aged 19–30 y, and BMI of 27.0–39.9 kg/m2 at baseline provided stool samples at baseline and 3, 6, and 9 mo of a randomized dietary weight loss trial. Diet was assessed by 1–2 24-h recalls. The abundance of SCFA-producing microbes was measured using 16S rRNA gene sequencing. GC-MS measured fecal SCFA (acetate, butyrate, propionate, and total) concentrations. Adjusted and Bonferroni-corrected generalized estimating equations modeled associations of dietary fiber (total, soluble, and pectins) and carbohydrate (available carbohydrate, and fructose) with microbiome-related outcomes. Primary analyses were restricted to data collected before COVID-19 interruptions. Results: Fiber (total and soluble) and carbohydrates (available and fructose) were positively associated with total SCFA and acetate concentrations (n = 40 participants, 52 visits). Each 10 g/d of total and soluble fiber intake was associated with an additional 8.8 μmol/g (95% CI: 4.5, 12.8 μmol/g; P = 0.006) and 24.0 μmol/g (95% CI: 12.9, 35.1 μmol/g; P = 0.003) of fecal acetate, respectively. Available carbohydrate intake was positively associated with SCFA producers Roseburia and Ruminococcus gnavus. All diet variables except pectin were inversely associated with normalized abundance of Bacteroides and Alistipes. Fructose was inversely associated with Akkermansia abundance. Conclusions: In young adults with longstanding T1D, fiber and carbohydrate intake were associated positively with fecal SCFA but had variable associations with SCFA-producing gut microbes. Controlled feeding studies should determine whether gut microbes and SCFA can be directly manipulated in T1D

Virus infection and grazing exert counteracting influences on survivorship of native bunchgrass seedlings competing with invasive exotics

1.  Invasive annual grasses introduced by European settlers have largely displaced native grassland vegetation in California and now form dense stands that constrain the establishment of native perennial bunchgrass seedlings. Bunchgrass seedlings face additional pressures from both livestock grazing and barley and cereal yellow dwarf viruses (B/CYDVs), which infect both young and established grasses throughout the state. 2.  Previous work suggested that B/CYDVs could mediate apparent competition between invasive exotic grasses and native bunchgrasses in California. 3.  To investigate the potential significance of virus-mediated mortality for early survivorship of bunchgrass seedlings, we compared the separate and combined effects of virus infection, competition and simulated grazing in a field experiment. We infected two species of young bunchgrasses that show different sensitivity to B/CYDV infection, subjected them to competition with three different densities of exotic annuals crossed with two clipping treatments, and monitored their growth and first-year survivorship. 4.  Although virus infection alone did not reduce first-year survivorship, it halved the survivorship of bunchgrasses competing with exotics. Within an environment in which competition strongly reduces seedling survivorship (as in natural grasslands), virus infection therefore has the power to cause additional seedling mortality and alter patterns of establishment. 5.  Surprisingly, clipping did not reduce bunchgrass survivorship further, but rather doubled it and disproportionately increased survivorship of infected bunchgrasses. 6.  Together with previous work, these findings show that B/CYDVs can be potentially powerful elements influencing species interactions in natural grasslands. 7.  More generally, our findings demonstrate the potential significance of multitrophic interactions in virus ecology. Although sometimes treated collectively as plant ‘predators’, viruses and herbivores may exert influences that are distinctly different, even counteracting

Associations of disordered eating with the intestinal microbiota and short-chain fatty acids among young adults with type 1 diabetes

Background and aims: Disordered eating (DE) in type 1 diabetes (T1D) includes insulin restriction for weight loss with serious complications. Gut microbiota-derived short chain fatty acids (SCFA) may benefit host metabolism but are reduced in T1D. We evaluated the hypothesis that DE and insulin restriction were associated with reduced SCFA-producing gut microbes, SCFA, and intestinal microbial diversity in adults with T1D. Methods and results: We collected stool samples at four timepoints in a hypothesis-generating gut microbiome pilot study ancillary to a weight management pilot in young adults with T1D. 16S ribosomal RNA gene sequencing measured the normalized abundance of SCFA-producing intestinal microbes. Gas-chromatography mass-spectrometry measured SCFA (total, acetate, butyrate, and propionate). The Diabetes Eating Problem Survey—Revised (DEPS-R) assessed DE and insulin restriction. Covariate-adjusted and Bonferroni-corrected generalized estimating equations modeled the associations. COVID-19 interrupted data collection, so models were repeated restricted to pre-COVID-19 data. Data were available for 45 participants at 109 visits, which included 42 participants at 65 visits pre-COVID-19. Participants reported restricting insulin “At least sometimes” at 53.3% of visits. Pre-COVID-19, each 5-point DEPS-R increase was associated with a −0.34 (95% CI -0.56, −0.13, p = 0.07) lower normalized abundance of genus Anaerostipes; and the normalized abundance of Lachnospira genus was −0.94 (95% CI -1.5, −0.42), p = 0.02 lower when insulin restriction was reported “At least sometimes” compared to “Rarely or Never”. Conclusion: DE and insulin restriction were associated with a reduced abundance of SCFA-producing gut microbes pre-COVID-19. Additional studies are needed to confirm these associations to inform microbiota-based therapies in T1D

Business excellence model: an overarching framework for managing and aligning multiple organisational improvement initiatives

Business Excellence Models (BEMs) are used by organisations to assess and improve their work practices and performance. The authors’ research identified that there are currently 94 national Quality/Business Excellence (BE) Awards used in 83 countries. While the use of BEMs is widespread, it was identified that many organisations wanted guidance in terms of which improvement initiatives to implement to assist them on their BE journey. This paper discusses how the BEM can be used as an overarching framework for managing and/or aligning multiple improvement initiatives within the organisation. A new model is developed showing some of the main improvement initiatives that can be adopted towards achieving BE, which are arranged according to the common enabling criteria of BEMs and levels of BE maturity. This proposed model can be used as a pathway/roadmap to BE. In developing this model, a literature review, a document review and several semi-structured interviews were conducted. Sixteen quality and BE experts were interviewed in New Zealand, Singapore, and Malaysia

The trans-ancestral genomic architecture of glycemic traits

Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 x 10(-8)), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.A trans-ancestry meta-analysis of GWAS of glycemic traits in up to 281,416 individuals identifies 99 novel loci, of which one quarter was found due to the multi-ancestry approach, which also improves fine-mapping of credible variant sets.Diabetes mellitus: pathophysiological changes and therap

Experimental measurement of nitrogen oxide emission factors for lab-scale flares

NOx emissions are a factor in all combustion systems, and uncontrolled stoichiometric combustion in typical upstream oil and gas (UOG) industry flares has the potential to produce the higher temperatures needed for thermally dependent NOx formation. The applicability of these factors to flares typical of the UOG industry is questionable based on the fuels used and the Froude numbers studied. The subset of flares that operate in a continuous manner burning solution gas that is a by-product of oil production were investigated. Experimental NOx emission data were collected for laboratory-scale flares at Froude number conditions representing UOG flaring conditions based on two independent studies and measurements of real world flares. An adjusted scaling law for NOx emissions based on the theoretical correlation with Fr3/5 fitted well to the data measured. The scaling factor obtained was lower than previously published results by up to a factor of six; however the accuracy of the measurements precludes recommendations as to its application before additional experiments and analysis can be conducted. This is an abstract of a paper presented at the 105th AWMA Annual Conference and Exhibition 2012 (San Antonio, TX 6/19-22/2012)

Methodologies and uncertainties for measuring black carbon and NOx from lab-scale and in situ upstream oil and gas flares

Black carbon and NOx from a laboratory-scale flare tip burning a gas mixture representative of solution gas flares typical of the Alberta upstream oil and gas industry were measured. A new and robust method for calculation of carbon conversion efficiency and species emission rates was developed for use in ongoing flare tests and possible field measurements on in situ flares. Fuel flow rates ranged from 30 to 268 standard L/min with exit velocities ranging from 0.25 to 2.5 m/sec. In general, combustion efficiency increased with fuel flow rate while soot production decreased. Soot was at a maximum of 0.1% of fuel carbon mass for the fuel flow rates tested. Uncertainties on combustion efficiency and species production rates were strongly dependent on dilution ratio making dilution of the combustion products with ambient air an important factor for planning in situ measurements. This is an abstract of a paper presented at the AWMA's 107th Annual Conference & Exhibition (Long Beach, CA 6/24-27/2014)

Detailed expressions and methodologies for measuring flare combustion efficiency, species emission rates, and associated uncertainties

Two complementary analytical methods for quantifying carbon conversion efficiency and species emission rates of gas flares in the form of turbulent nonpremixed flames are derived and tested experimentally. Full mathematical expressions for partial derivative terms necessary to facilitate quantitative uncertainty analysis are also derived and presented as Supporting Information. Key assumptions are individually tested and the resulting generalized expressions are quantitatively compared with several other simplified expressions for calculating flare efficiency found in the literature. The first approach uses a carbon-balance approach to link measured concentrations of diluted combustion products to known flare gas outlet conditions while considering both the dilution of the combustion products and ambient levels of relevant species in the dilution and combustion air. This method is further extended to allow explicit consideration of solid-phase black carbon (soot) that may be present in the products. A second distinct method utilizes a tracer gas injected into the diluted plume to enable quantification of species emission rates from the combustion process directly. Experiments reveal how the two approaches each have advantages in different situations allowing experiments to be better optimized to reduced uncertainties. In addition, the tracer injection method is extensible for use in quantifying efficiencies and liquid-fallout on flares burning a mixed-phase fuel stream