Supply of palmitic, stearic, and oleic acid changes rumen fiber digestibility and microbial composition.

The concept that fat supplementation impairs total-tract fiber digestibility in ruminants has been widely accepted over the past decades. Nevertheless, the recent interest in the dietary fatty acid profile to dairy cows enlightened the possible beneficial effect of specific fatty acids (e.g.

Supplementing branched-chain volatile fatty acids in dual-flow cultures varying in dietary forage and corn oil concentrations. I: Digestibility, microbial protein, and prokaryotic community structure.

Branched-chain amino acids are deaminated by amylolytic bacteria to branched-chain volatile fatty acids (BCVFA), which are growth factors for cellulolytic bacteria. Our objective was to determine the dietary conditions that would increase the uptake of BCVFA by rumen bacteria. We hypothesized that increased forage would increase cellulolytic bacterial abundance and incorporation of BCVFA into their structure.

Network analysis to evaluate complexities in relationships among fermentation variables measured within continuous culture experiments.

The objective of this study was to leverage a frequentist (ELN) and Bayesian learning (BLN) network analyses to summarize quantitative associations among variables measured in 4 previously published dual-flow continuous culture fermentation experiments. Experiments were originally designed to evaluate effects of nitrate, defaunation, yeast, and/or physiological shifts associated with pH or solids passage rates on rumen conditions. Measurements from these experiments that were used as nodes within the networks included concentrations of individual volatile fatty acids, mM and nitrate, NO3-,%; outflows of non-ammonia nitrogen (NAN, g/d), bacterial N (BN, g/d), residual N (RN, g/d), and ammonia N (NH3-N, mg/dL); degradability of neutral detergent fiber (NDFd, %) and degradability of organic matter (OMd, %); dry matter intake (DMI, kg/d); urea in buffer (%); fluid passage rate (FF, L/d); total protozoa count (PZ, cells/mL); and methane production (CH4, mmol/d).

Effect of zinc source (zinc sulfate or zinc hydroxychloride) on relative abundance of fecal spp. in lactating dairy cows.

Previous research revealed a potential effect of dietary trace mineral source on both ruminal and fecal microbiota. However, the effect of Zn source, specifically, has not previously been considered. Based on reported postruminal solubility, we hypothesized that Zn hydroxychloride would decrease spp.

Effects of acetate, propionate, and pH on volatile fatty acid thermodynamics in continuous cultures of ruminal contents.

To investigate the effects of acetate, propionate, and pH on thermodynamics of volatile fatty acids (VFA) in the rumen, a dual-flow continuous culture study was conducted to quantify production of major VFA, interconversions among the VFA, and H and CH emissions in a 4 × 4 Latin square design. The 4 treatments were (1) control: pH buffered to an average of 6.75; (2) control plus 20 mmol/d of infused acetate (InfAc); (3) control plus 7 mmol/d of infused propionate (InfPr); and (4) a 0.

Effects of Atrial Fibrillation on the Human Ventricle.

Rationale: Atrial fibrillation (AF) and heart failure often coexist, but their interaction is poorly understood. Clinical data indicate that the arrhythmic component of AF may contribute to left ventricular (LV) dysfunction.

Objective: This study investigates the effects and molecular mechanisms of AF on the human LV.

Sparking curiosity and engagement through online curriculum.

In 2020, classrooms across the country abruptly transitioned to emergency remote learning in response to COVID-19. Instructors quickly searched for guidance on ways to present course material in an online format that would still allow for course learning outcomes to be met. Perhaps the greatest challenge cited by instructors was engaging students when face-to-face meetings were not an option.

Silicon-nitride microring resonators for nonlinear optical and biosensing applications.

We discuss the design, fabrication, and characterization of silicon-nitride microring resonators for nonlinear-photonic and biosensing device applications. The first part presents new theoretical and experimental results that overcome highly normal dispersion of silicon-nitride microresonators by adding a dispersive coupler. The latter parts review our work on highly efficient second-order nonlinear interaction in a hybrid silicon-nitride slot waveguide with nonlinear polymer cladding and silicon-nitride microring application as a biosensor for human stress indicator neuropeptide Y at the nanomolar level.

Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. III: Relation with solid passage rate and pH on prokaryotic fatty acid profile and community in continuous culture.

Our objectives were to evaluate potential interactions in culture conditions that influence how exogenously dosed branched-chain VFA (BCVFA) would be recovered as elongated fatty acids (FA) or would affect bacterial populations. A 2 × 2 × 2 factorial arrangement of treatments evaluated 3 factors: (1) without versus with BCVFA (0 vs. 2 mmol/d each of isobutyrate, isovalerate, and 2-methylbutyrate; each dose was partially substituted with C-enriched tracers before and during the collection period); (2) high versus low pH (ranging diurnally from 6.

Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. II: Relation with solid passage rate and pH on neutral detergent fiber degradation and microbial function in continuous culture.

To support improving genetic potential for increased milk production, intake of digestible carbohydrate must also increase to provide digestible energy and microbial protein synthesis. We hypothesized that the provision of exogenous branched-chain volatile fatty acids (BCVFA) would improve both neutral detergent fiber (NDF) degradability and efficiency of microbial protein synthesis. However, BCVFA should be more beneficial with increasing efficiency of bacterial protein synthesis associated with increasing passage rate (k).

Inhibition of methanogenesis by nitrate, with or without defaunation, in continuous culture.

Within the rumen, nitrate can serve as an alternative sink for aqueous hydrogen [H(aq)] accumulating during fermentation, producing nitrite, which ideally is further reduced to ammonium but can accumulate under conditions not yet explained. Defaunation has also been associated with decreased methanogenesis in meta-analyses because protozoa contribute significantly to H production. In the present study, we applied a 2 × 2 factorial treatment arrangement in a 4 × 4 Latin square design to dual-flow continuous culture fermentors (n = 4).

Quantification of Neuropeptide Y with Picomolar Sensitivity Enabled by Guided-Mode Resonance Biosensors.

Assessing levels of neuropeptide Y (NPY) in the human body has many medical uses. Accordingly, we report the quantitative detection of NPY biomarkers applying guided-mode resonance (GMR) biosensor methodology. The label-free sensor operates in the near-infrared spectral region exhibiting distinctive resonance signatures.

Pelleted-hay alfalfa feed increases sheep wether weight gain and rumen bacterial richness over loose-hay alfalfa feed.

Diet composed of smaller particles can improve feed intake, digestibility, and animal growth or health, but in ruminant species can reduce rumination and buffering-the loss of which may inhibit fermentation and digestibility. However, the explicit effect of particle size on the rumen microbiota remains untested, despite their crucial role in digestion. We evaluated the effects of reduced particle size on rumen microbiota by feeding long-stem (loose) alfalfa hay compared to a ground and pelleted version of the same alfalfa in yearling sheep wethers during a two-week experimental period.

Potential roles of nitrate and live yeast culture in suppressing methane emission and influencing ruminal fermentation, digestibility, and milk production in lactating Jersey cows.

Concern over the carbon footprint of the dairy industry has led to various dietary approaches to mitigate enteric CH production. One approach is feeding the electron acceptor NO, thus outcompeting methanogens for aqueous H. We hypothesized that a live yeast culture (LYC; Saccharomyces cerevisiae from Yea-Sacc 1026, Alltech Inc.

Rumen microbial responses to supplemental nitrate. II. Potential interactions with live yeast culture on the prokaryotic community and methanogenesis in continuous culture.

Nitrates have been fed to ruminants, including dairy cows, as an electron sink to mitigate CH emissions. In the NO reduction process, NO can accumulate, which could directly inhibit methanogens and possibly other microbes in the rumen. Saccharomyces cerevisiae yeast was hypothesized to decrease NO through direct reduction or indirectly by stimulating the bacterium Selenomonas ruminantium, which is among the ruminal bacteria most well characterized to reduce both NO and NO.

Rumen microbial responses to supplemental nitrate. I. Yeast growth and protozoal chemotaxis in vitro as affected by nitrate and nitrite concentrations.

Nitrates have been fed to ruminants, including dairy cows, as an electron sink to mitigate CH emissions. In the NO reduction process, NO can accumulate, which could directly inhibit methanogens and some bacteria. However, little information is available on eukaryotic microbes in the rumen.

Investigation of ammonium lactate supplementation on fermentation end products and bacterial assimilation of nitrogen in dual-flow continuous culture.

Supplements investigated throughout the present study are produced by fermenting lactose that is present in whey to lactate, yielding products differing in ammonium relative to lactate concentrations and in physical form (liquid or dry). Trials 1 and 2 investigated Lacto-Whey (LW; Fermented Nutrition Corp., Luxemburg, WI) and GlucoBoost (GB; Fermented Nutrition Corp.

Efficient broadband energy detection from the visible to near-infrared using a plasmon FET.

Plasmon based field effect transistors (FETs) can be used to convert energy induced by incident optical radiation to electrical energy. Plasmonic FETs can efficiently detect incident light and amplify it by coupling to resonant plasmonic modes thus improving selectivity and signal to noise ratio. The spectral responses can be tailored both through optimization of nanostructure geometry as well as constitutive materials.

Using video microscopy to improve quantitative estimates of protozoal motility and cell volume.

The objective of this study was to apply digital imaging to improve quantification of rumen protozoal biomass and distinguish treatment differences in cell motility and volume among ruminal protozoa. Observations of protozoa in rumen fluid treated with essential oils (CinnaGar, CIN; Provimi North America, Brookville, OH) or an ionophore (monensin, MON) indicated possible cell shrinkage. We hypothesized that MON would decrease protozoal motility and interact with CIN on cell volume.

Association of aqueous hydrogen concentration with methane production in continuous cultures modulated to vary pH and solids passage rate.

The objective of this study was to evaluate the effects of altering pH and solids passage rate (k) on concentration of aqueous H [H(aq)], CH production, volatile fatty acids (VFA) production, and fiber digestibility in a continuous culture fermentation system. The present study was conducted as a 2 × 2 factorial treatment arrangement in a Latin square design using continuous culture fermentors (n = 4). Our continuous culture system was converted to a closed system to measure CH and H emission while measuring H(aq) concentration and VFA production for complete stoichiometric assessment of fermentation pattern.

Source of supplemental dietary copper, zinc, and manganese affects fecal microbial relative abundance in lactating dairy cows.

Appropriate trace mineral supplementation can improve immune response and hoof health in cattle and at much higher rates of supplementation to swine and poultry can alter microbial colonization of the gut, resulting in improved gut health. Diet can influence fecal microbial excretion in cattle, and the fecal microbiome may serve as a means for assessing gastrointestinal microbial changes. We hypothesized that feeding diets that differed in source of supplemental Cu, Zn, or Mn would alter the relative abundance of fecal microbes in lactating dairy cattle and that organic Zn would have the greatest effect.

Enhanced responsivity resonant RF photodetectors.

The responsivity of room-temperature, semiconductor-based photodetectors consisting of resonant RF circuits coupled to microstrip buslines is investigated. The dependence of the photodetector response on the semiconductor material and RF circuit geometry is presented, as is the detector response as a function of the spatial position of the incident light. We demonstrate significant improvement in detector response by choice of photoconductive material, and for a given material, by positioning our optical signal to overlap with positions of RF field enhancement.

Adenylosuccinate Is an Insulin Secretagogue Derived from Glucose-Induced Purine Metabolism.

Pancreatic islet failure, involving loss of glucose-stimulated insulin secretion (GSIS) from islet β cells, heralds the onset of type 2 diabetes (T2D). To search for mediators of GSIS, we performed metabolomics profiling of the insulinoma cell line 832/13 and uncovered significant glucose-induced changes in purine pathway intermediates, including a decrease in inosine monophosphate (IMP) and an increase in adenylosuccinate (S-AMP), suggesting a regulatory role for the enzyme that links the two metabolites, adenylosuccinate synthase (ADSS). Inhibition of ADSS or a more proximal enzyme in the S-AMP biosynthesis pathway, adenylosuccinate lyase, lowers S-AMP levels and impairs GSIS.

Mechanical unloading promotes myocardial energy recovery in human heart failure.

Background: Impaired bioenergetics is a prominent feature of the failing heart, but the underlying metabolic perturbations are poorly understood.

Methods And Results: We compared metabolomic, gene transcript, and protein data from 6 paired samples of failing human left ventricular tissue obtained during left ventricular assist device insertion (heart failure samples) and at heart transplant (post-left ventricular assist device samples). Nonfailing left ventricular wall samples procured from explanted hearts of patients with right heart failure served as novel comparison samples.

Guided-mode resonant coherent light absorbers.

We present a new class of coherent perfect absorbers based on guided-mode resonance in thin semiconductor films. Using particle-swarm optimization methods, we design a thin-film amorphous silicon grating that maximizes coherent modulation of the absorbance. The optimized device exhibits a maximum scattering power of ∼94% and a power absorption limit approaching 100% at the 1550-nm wavelength.