High repetition-rate dual-channel X-ray spectrometer for high-intensity laser-plasma experiments.

We describe the development and demonstration of a high-repetition-rate-capable dual-channel (DC) x-ray spectrometer designed for high-intensity laser-plasma experiments (≥1×1021 W/cm2). The spectrometer, which operates at high repetition rates, is limited only by the refresh rate of targets and the camera's frame rate. It features two channels, each equipped with a flat highly oriented pyrolytic graphite (HOPG) crystal and a unique detector plane, allowing it to resolve two distinct x-ray bands: approximately 7-10 and 10-13 keV. Each detector plate carrier holds two slots for active (scintillators) or passive (imaging plates) x-ray detectors. We present the design and testing of the HR-DC-HOPG using both the COMET laser (10 J, 0.5 ps shot/4 min) at LLNL's Jupiter Laser Facility and the SCARLET laser (10 J, 30 fs shot/min) at Ohio State University. The results demonstrate the spectrometer's performance across various laser energies, target materials, pulse shapes, and detector types.

An experimental platform for investigation of the Zeeman effect in strong magnetic fields.

An experimental platform is developed for the investigation of the Zeeman effect in strong magnetic fields. Mega-Gauss magnetic fields are generated by a 1 MA Zebra pulsed power machine using metal rod loads. A gas jet or CH oil on the load is the source of hydrogen. Excited hydrogen atoms are backlit by black body radiation from the rod load. Hydrogen absorption spectra are recorded with a grating spectrometer and intensified gated CCD camera. The experimental platform enables the observation of the quadratic Zeeman effect in hydrogen gas jets using the spectral shift of the central line in the Zeeman triplet. Other gases can be studied using the gas jet method.

Flexible tape-drive target system for secondary high-intensity laser-driven sources.

We present the development of a flexible tape-drive target system to generate and control secondary high-intensity laser-plasma sources. Its adjustable design permits the generation of relativistic MeV particles and x rays at high-intensity (i.e., ≥1 × 1018 W cm-2) laser facilities, at high repetition rates (>1 Hz). The compact and robust structure shows good mechanical stability and a high target placement accuracy (<4 µm RMS). Its compact and flexible design allows for mounting in both the horizontal and vertical planes, which makes it practical for use in cluttered laser-plasma experimental setups. The design permits ∼170° of access on the laser-driver side and 120° of diagnostic access at the rear. A range of adapted apertures have been designed and tested to be easily implemented to the targetry system. The design and performance testing of the tape-drive system in the context of two experiments performed at the COMET laser facility at the Lawrence Livermore National Laboratory and at the Advanced Lasers and Extreme Photonics (ALEPH) facility at Colorado State University are discussed. Experimental data showing that the designed prototype is also able to both generate and focus high-intensity laser-driven protons at high repetition rates are also presented.

Colostrum insulin supplementation to neonatal Holstein bulls affects small intestinal histomorphology, mRNA expression, and enzymatic activity with minor influences on peripheral metabolism.

The objectives of this study were to evaluate how varying colostral insulin concentrations influenced small intestinal development and peripheral metabolism in neonatal Holstein bulls. Insulin was supplemented to approximately 5× (70.0 µg/L; n = 16) or 10× (149.7 µg/L; n = 16) the basal colostrum insulin (12.9 µg/L; BI, n = 16) concentration to maintain equivalent macronutrient intake (crude fat: 4.1 ± 0.06%; crude protein: 11.7 ± 0.05%; and lactose: 1.9 ± 0.01%) among treatments. Colostrum was fed at 2, 14, and 26 h postnatal and blood metabolites and insulin concentration were measured at 0, 30, 60, 90, 120, 180, 240, 360, 480, and 600 min postprandial respective to the first and second colostrum meal. At 30 h postnatal, a subset of calves (n = 8/treatment) were killed to excise the gastrointestinal and visceral tissues. Gastrointestinal and visceral gross morphology and dry matter and small intestinal histomorphology, gene expression, and carbohydrase activity were assessed. Insulin supplementation tended to linearly reduce the glucose clearance rate following the first meal, whereas after the second meal, supplementation linearly increased the rate of glucose absorption and nonesterified fatty acid clearance rate, decreased the time to maximum glucose concentrations, and decreased the time to reach minimum nonesterified fatty acid concentrations. Additionally, insulin clearance rate was linearly increased by insulin supplementation following the second colostrum feeding. However, there were no overall differences between treatments in the concentrations of glucose, nonesterified fatty acids, or insulin in plasma or serum. With respect to macroscopic intestinal development, dry rumen tissue mass linearly decreased when insulin was supplemented in colostrum, and supplementation linearly increased duodenal dry tissue density (g dry matter/cm) while tending to increase duodenal dry tissue weight. Increasing the colostrum insulin concentration improved small intestinal histomorphological development in the distal small intestine, as ileal villi height and mucosal-serosal surface area index were increased by supplementing insulin. Lactase enzymatic activity linearly increased in the proximal jejunum while ileal isomaltase activity linearly decreased with insulin supplementation. These data indicate that changes in colostrum insulin concentrations rapidly affect gastrointestinal growth prioritization and carbohydrase activity. The changes in gastrointestinal ontology result in minor changes in postprandial metabolite availability and clearance.

Timing and duration of nutrient restriction and its impacts on placental development and umbilical blood flow in adolescent sheep.

We hypothesized that nutrient restriction from day 50-90 of gestation decreases umbilical blood flow and that umbilical blood flow would recover to control values upon realimentation during late gestation (d 90 to 130) or remain reduced in ewes that continued to be nutrient restricted. On d 50 of gestation, young nulliparous whiteface ewes (6-8 mo; n = 41) carrying singletons were randomly assigned to two dietary treatments: 100% of NRC recommendations (CON) or 60% of CON (RES). On d 90 of gestation, ewes either remained on CON or RES until d 130, or CON ewes were RES from d 90 to 130, or RES ewes were realimented to CON from d 90 to 130. This resulted in 4 treatment groups on day 130: CON-CON, CON-RES, RES-RES, RES-CON. Umbilical blood flow and fetal and placental measurements were obtained via ultrasonography every 10 days from day 50-110. Non-survival surgeries were performed on days 50, 90, and 130 (n = 6-7 ewes/group) where uterine artery and umbilical blood flows were measured during surgery via ultrasonography. Conceptus weights were recorded and placentomes collected to determine binucleate cell numbers. The study was conducted as a completely randomized design arrangement with repeated measures. Data were analyzed using the MIXED procedure of SAS. There was a nutritional treatment by day interaction (P < 0.01) with CON ewes having greater umbilical blood flow compared with RES by d 90. Fetal biparietal distance, abdominal width, and kidney area increased (P < 0.05) in CON-RES with all these measurements increasing during late gestation. We partially accept our hypothesis as nutrient restriction during mid gestation decreased umbilical blood flow. However, blood flow did not return to control levels upon realimentation. By d 130, fetal and placental weights were similar between RES-RES and CON-CON. Binucleate cell numbers in the fetal trophoblast were not influenced by nutritional treatments. Our findings suggest that refeeding previously nutrient restricted pregnant adolescent ewes to control levels does not reestablish umbilical blood flow. Adequate placental development during mid gestation could protect the fetus from a decreased umbilical blood flow later in gestation when nutrients were limited by 40%.

A flexible proton beam imaging energy spectrometer (PROBIES) for high repetition rate or single-shot high energy density (HED) experiments (invited).

The PROBIES diagnostic is a new, highly flexible, imaging and energy spectrometer designed for laser-accelerated protons. The diagnostic can detect low-mode spatial variations in the proton beam profile while resolving multiple energies on a single detector or more. When a radiochromic film stack is employed for "single-shot mode," the energy resolution of the stack can be greatly increased while reducing the need for large numbers of films; for example, a recently deployed version allowed for 180 unique energy measurements spanning ∼3 to 75 MeV with <0.4 MeV resolution using just 20 films vs 180 for a comparable traditional film and filter stack. When utilized with a scintillator, the diagnostic can be run in high-rep-rate (>Hz rate) mode to recover nine proton energy bins. We also demonstrate a deep learning-based method to analyze data from synthetic PROBIES images with greater than 95% accuracy on sub-millisecond timescales and retrained with experimental data to analyze real-world images on sub-millisecond time-scales with comparable accuracy.

Research needs, environmental concerns, and logistical considerations for incorporating livestock grazing into coastal upland habitat management.

Along the Gulf of Mexico (GoM) coast, natural resource managers continually struggle with managing coastal uplands due to front-end costs, prolonged maintenance, and habitat-specific ecological needs. Prescribed fire, mechanical removal, and chemical treatments are common habitat management techniques used to remove invasive species, clear understory, and achieve other management goals. However, rapid development and changing climate exacerbate the difficulty in using these techniques. A potential alternative or complementary technique is using livestock for habitat management (i.e., targeted or controlled grazing). In other regions of the world, using livestock for conservation or restoration of managed lands has shown to be a less intrusive and more financially viable alternative. To better understand the research needs, logistical, and environmental concerns related to using livestock for habitat management in the coastal uplands of the GoM, we developed and distributed a survey to three groups of land users, including natural resource managers, researchers, and livestock producers in the region. Survey results show that over 96% of respondents are interested in using livestock for habitat management, but less than 10% of respondents were aware of any information that could be used to inform grazing practices for coastal upland habitat management along the Gulf of Mexico coast. There were differences among surveyed groups, but generally small-sized cattle breeds and goats were identified as the livestock with the most potential for environmental benefit and ease of containment. General concerns and areas for further investigation were implementation (e.g., which livestock type to use and grazing intensity), logistical considerations (e.g., fencing and rotational frequency), impacts of grazing on water quality, wildlife, vegetation, and livestock nutrition. Survey respondents overwhelmingly (at least 75% of each group) indicated that livestock grazing ideally would not be a standalone management practice and should be used in conjunction with other habitat management techniques such as prescribed burns, mechanical clearing, or chemical treatments. The results of the survey could be used to develop applied research projects and guidance documents that directly address informational needs related to using livestock for habitat management of coastal uplands along the Gulf of Mexico coast.

Ultra-compact x-ray spectrometer for high-repetition-rate laser-plasma experiments.

We present in this work the development of an ultra-compact, multi-channel x-ray spectrometer (UCXS). This diagnostic has been specially built and adapted to perform at high-repetition-rate (>1 Hz) for high-intensity, short-pulse laser plasma experiments. X-ray filters of varying materials and thicknesses are chosen to provide spectral resolution up to ΔE ≈ 1 keV over the x-ray energy range of 1-30 keV. These filters are distributed over a total of 25 channels, where each x-ray filter is coupled to a single scintillator. The UCXS is designed to detect and resolve a large variety of laser-driven x-ray sources such as low energy bremsstrahlung emission, fluorescence, and betatron radiation (up to 30 keV). Preliminary results from commissioning experiments at the ABL laser facility at Colorado State University are provided.

Single-shot measurements of pulse-front tilt in intense ps laser pulses and its effect on accelerated electron and ion beam characteristics (invited).

We report recent single-shot spatiotemporal measurements of laser pulses, including pulse-front tilt (PFT) and spatial chirp, taken at the Compact Multipulse Terawatt laser at the Jupiter Laser Facility in Livermore, CA. STRIPED FISH, a device that measures the complete 3D electric field of fs to ps laser pulses on a single shot, was adapted to near infrared for these measurements. We present the design of the instrument used for these experiments, the on-shot measurements of systematic high-order PFT, and shot-to-shot variations in the measurements of spatiotemporal couplings. Finally, we simulate the effect of PFT in target normal sheath acceleration experiments. These simulations showed that pulse front tilt can steer hot electrons, shape the distribution of the accelerating sheath field, and increase the variability of cutoff energy in the resulting proton spectra. While these effects may be detrimental to experimental accuracy if the pulse front tilt is left unmeasured, hot electron steering shows promise for precision manipulation of the particle source for a range of applications, including irradiation of secondary targets for opacity measurements, radiography, or neutron generation.

Applications of machine learning to a compact magnetic spectrometer for high repetition rate, laser-driven particle acceleration.

Accurately and rapidly diagnosing laser-plasma interactions is often difficult due to the time-intensive nature of the analysis and will only become more so with the rise of high repetition rate lasers and the desire to implement feedback on a commensurate timescale. Diagnostic analysis employing machine learning techniques can help address this problem while maintaining a high degree of accuracy. We report on the application of machine learning to the analysis of a scintillator-based electron spectrometer for experiments on high intensity, laser-plasma interactions at the Colorado State University Advanced Lasers and Extreme Photonics facility. Our approach utilizes a neural network trained on synthetic data and tested on experiments to extract the accelerated electron temperature. By leveraging transfer learning, we demonstrate an improvement in the neural network accuracy, decreasing the network error by 50%.

Quadratic Zeeman effect in hydrogen at 2-3 MG magnetic fields.

The Zeeman effect is used for measurement of magnetic fields in astrophysical and laboratory plasmas. Magnetic fields in atmospheres of magnetic white dwarf stars are in the range 40 kG-1 GG. The quadratic Zeeman effect results in the additional split and shift of lines for magnetic fields >2 MG. Hydrogen Balmer lines were studied in magnetic fields delivered by a 1 MA pulse power generator. The magnetic field was generated by rod loads 0.8-1 mm in diameter. A droplet of CH oil on the load center was the source of hydrogen. A low ionized oil layer was backlit by blackbody emission from the rod with a temperature of 0.5-0.6 eV. Zeeman splitting of H-alpha and H-beta absorption lines were with a grating spectrometer. A spectral shift of the central component of the triplet indicated the quadratic Zeeman effect in hydrogen lines.

Effects of nutrient restriction and subsequent realimentation in pregnant beef cows: Maternal endocrine profile, umbilical hemodynamics, and mammary gland development and hemodynamics.

Our hypothesis was that maternal nutrient restriction would negatively impact the endocrine and metabolic status of the pregnant cow, therefore influencing the mammary gland in preparation for lactation. We further hypothesized that earlier timing of realimentation could prevent negative impacts of nutrient restriction. The objectives were to investigate the influence of nutrient restriction and realimentation during early to late gestation on endocrine profile, umbilical hemodynamics, and mammary gland development and hemodynamics in pregnant beef cows. In Experiment 1, on d 30 of pregnancy cows (initial BW = 667.5 ± 13.4 kg, BCS = 6.2 ± 0.1) were randomly assigned to one of 3 treatments: 1) 100% NRC requirements from d 30 to 254 of gestation (CCC; n = 6); 2) 60% NRC from d 30 to 85, thereafter being re-alimented to 100% NRC to d 254 (RCC; n = 5); 3) or receive 60% NRC from d 30 to 140, thereafter being re-alimented to 100% NRC to d 254 (RRC; n = 6). Cows were returned to a common outdoor facility for calving thereafter and were fed ad libitum. In Experiment 2, on d 30 of pregnancy, cows (initial BW = 620.5 ± 11.3 kg, BCS = 5.1 ± 0.1) were randomly assigned to dietary treatments including: control (CON; 100% NRC; n = 18) and nutrient restriction (RES; 60% NRC; n = 30). On d 85 of pregnancy, cows were either slaughtered (CON, n = 6 and RES, n = 6), remained on control (CC; n = 12) and restricted (RR; n = 12) treatments, or were realimented to control (RC; n = 11). On d 140 of pregnancy, cows were either slaughtered (CC, n = 6; RR, n = 6; RC, n = 5), remained on control (CCC, n = 6; RCC, n = 5), or were realimented to control (RRC, n = 6). On d 254 of pregnancy, all remaining cows were slaughtered (CCC, n = 6; RCC, n = 5; RRC, n = 6). Mammary hemodynamics and endocrine profile were measured. Serum urea nitrogen, NEFA, as well as fetal parameters were measured in Experiment 1; whereas in Experiment 2, mammary gland development was recorded. In Experiment 1, RRC cows had lower dry matter intake (P = 0.001) and consequently lower BW change (P = 0.06). However, maternal nutrition did not alter mammary hemodynamics, hormonal patterns, and fetal characteristics (P > 0.11). In Experiment 2, CCC cows had increased (P = 0.02) mammary gland blood flow ipsilateral to the gravid horn as well as greater (P = 0.02) mammary gland fat on d 254. Nevertheless, plane of nutrition did not alter hormonal concentrations nor mammary gland characteristics (P > 0.15). These data indicate that nutrient restriction did not alter mammary hemodynamics nor endocrine profile throughout gestation.

Geographically diverse canid sampling provides novel insights into pre-industrial microbiomes.

Canine microbiome studies are often limited in the geographic and temporal scope of samples studied. This results in a paucity of data on the canine microbiome around the world, especially in contexts where dogs may not be pets or human associated. Here, we present the shotgun sequences of fecal microbiomes of pet dogs from South Africa, shelter and stray dogs from India, and stray village dogs in Laos. We additionally performed a dietary experiment with dogs housed in a veterinary medical school, attempting to replicate the diet of the sampled dogs from Laos. We analyse the taxonomic diversity in these populations and identify the underlying functional redundancy of these microbiomes. Our results show that diet alone is not sufficient to recapitulate the higher diversity seen in the microbiome of dogs from Laos. Comparisons to previous studies and ancient dog fecal microbiomes highlight the need for greater population diversity in studies of canine microbiomes, as modern analogues can provide better comparisons to ancient microbiomes. We identify trends in microbial diversity and industrialization in dogs that mirror results of human studies, suggesting future research can make use of these companion animals as substitutes for humans in studying the effects of industrialization on the microbiome.

Development and integration of photonic Doppler velocimetry as a diagnostic for radiation driven experiments on the Z-machine.

Plasma density measurements are key to a wide variety of high-energy-density (HED) and laboratory astrophysics experiments. We present a creative application of photonic Doppler velocimetry (PDV) from which time- and spatially resolved electron density measurements can be made. PDV has been implemented for the first time in close proximity, ∼6 cm, to the high-intensity radiation flux produced by a z-pinch dynamic hohlraum on the Z-machine. Multiple PDV probes were incorporated into the photoionized gas cell platform. Two probes, spaced 4 mm apart, were used to assess plasma density and uniformity in the central region of the gas cell during the formation of the plasma. Electron density time histories with subnanosecond resolution were extracted from PDV measurements taken from the gas cells fielded with neon at 15 Torr. As well, a null shot with no gas fill in the cell was fielded. A major achievement was the low noise high-quality measurements made in the harsh environment produced by the mega-joules of x-ray energy emitted at the collapse of the z-pinch implosion. To evaluate time dependent radiation induced effects in the fiber optic system, two PDV noise probes were included on either side of the gas cell. The success of this alternative use of PDV demonstrates that it is a reliable, precise, and affordable new electron density diagnostic for radiation driven experiments and more generally HED experiments.

Acute effects of estradiol-17ß on plasma volume and uterine cell proliferation in sheep.

Ovarian steroids play an important role in increasing plasma volume in pregnant females and preparing the uterus for implantation. We hypothesized that a short duration of increased estradiol-17ß (E2) would increase plasma volume and uterine cell proliferation in ovariectomized ewes. Adult non-pregnant Romanov ewes (n = 15) were ovariectomized. After ovariectomy, ewes were individually housed and were offered water at ad libitum intake and were fed a pelleted diet at maintenance once daily according to body weight. After at least 30 days post-ovariectomy ewes were fasted and received an implant placed in the axillary region that contained 100 mg of E2 (E2; n = 8) or a sham implant with no E2 (CON, n = 7). After 24 h, ewes were weighed prior to plasma volume measurement procedures. Plasma volume was determined using the Evans blue dye method. Blood samples were taken at 0 (pre dye injection), 5, 10, 15, 20, 25, 30, 40, 50 and 60 min after dye injection. After the final blood collection, ewes were euthanized with an overdose of sodium pentabarbital and uterine weights were recorded. Uterine cross-sections were fixed in formalin for immunohistochemical localization of Ki67 (a marker of proliferating cells) followed by image generation of luminal epithelium and endometrial stroma (5 areas each/tissue section) and analysis to determine the proportion of proliferating cells. Plasma volume tended to be greater in E2 vs CON (2.75 ± 0.11 vs. 2.54 ± 0.12 L, P = 0.07) and uterine weights were greater in E2 vs CON (27.25 ± 2.35 vs. 17.35 ± 2.51 g, P < 0.01). Water intake after implant placement was similar in E2 and CON (3.85 vs. 4.87 ± 0.67 L; P = 0.28). Cell proliferation in the luminal epithelium was greater in E2 vs CON (6.55 vs. 1.2 ± 1.75%, P = 0.02) and stromal cells tended to be greater in E2 vs CON (0.59 vs 0.37 ± 0.06%, P = 0.07). Our results demonstrate that E2-treatment tends to increase plasma volume acutely and increases uterine cell proliferation in ewes.

Feeding high amounts of almond hulls to lactating cows.

California is the leading state for the production of almonds, with more than 400,000 bearing hectares of orchards that produced approximately 1 billion kilograms of shelled nuts in 2017. Almond hulls (AH) are a regional by-product feedstuff fed predominantly to dairy cattle in California. A 2012 study surveyed 40 dairy farms in California and found that 39 out of 104 total mixed rations contained AH, with a mean daily feeding rate of 1.45 kg/cow. In 2017, approximately 2 billion kilograms of AH was produced. At a feeding rate of 1.45 kg/cow daily, even if all 1.7 million lactating cows in California are consuming AH, there will be a surplus of AH on the market as the approximately 130,000 nonbearing hectares come into nut production. Therefore, the potential of feeding varying amounts of AH to lactating dairy cows was investigated using 12 Holstein cows with 4 primiparous and 8 multiparous cows. The dietary treatments were 4 total mixed rations containing 0, 7, 13, or 20% AH. The AH used contained 12.8% crude fiber (as-is basis), which was below the 15% legal limit set by state feed regulations. Diets were formulated so that as the inclusion rate of AH increased, the amount of steam-flaked corn and soyhull pellets decreased and soybean meal inclusion increased. Experimental design was a replicated 4 × 4 Latin square. Diet had a cubic effect on actual milk yield, energy-corrected milk yield, and dry matter intake, with the 7% AH diet having the highest values and the 13% AH diet having the lowest. The percent and yield of total solids and the yields of lactose and fat did not differ with diet, but percent and yield of protein declined linearly with increased AH inclusion, and fat percent increased linearly. Apparent total-tract digestibilities of dry matter and organic matter were higher with the inclusion of AH in the diet. Total percentage of the day spent ruminating increased linearly with higher amounts of AH. Overall, this work demonstrated that AH can be fed at varying amounts, up to 20% of the diet, to lactating dairy cows to support high levels of milk production and that increasing amounts of AH (up to 20%) in the diet could lead to improved digestibility and milk fat percentage but decreased milk protein production.

Effects of nutrient restriction and melatonin supplementation from mid-to-late gestation on maternal and fetal small intestinal carbohydrase activities in sheep.

The objective of this experiment was to evaluate the effects of nutrient restriction and melatonin supplementation during mid-to-late gestation on maternal and fetal small intestinal carbohydrase activities in sheep. Ewes were randomly assigned to one of 4 dietary treatments arranged in a 2 × 2 factorial design. Ewes were fed to provide 100% (adequate; ADQ) or 60% (restricted; RES) of nutrient recommendations, and diets were supplemented with either no melatonin (control; CON) or 5 mg melatonin/d (melatonin; MEL). This resulted in 4 treatment groups: CON-ADQ (n = 7), CON-RES (n = 8), MEL-ADQ (n = 8), MEL-RES (n = 8). Treatments began on day 50 of gestation, and ewes were euthanized on day 130 for tissue collection. The maternal and fetal small intestine were collected and assayed for small intestinal carbohydrase activities. Data were analyzed using the GLM procedure of SAS with fetal sex, melatonin, nutrition, and the melatonin by nutrition interaction included in the model statement. There were no melatonin by nutrition interactions for maternal or fetal small intestinal protein concentration or carbohydrase activities (P ≥ 0.11). Dietary melatonin supplementation decreased (P = 0.03) maternal small intestinal protein concentration by 22.7% and increased (P = 0.03) maternal small intestinal glucoamylase, isomaltase, and maltase activity per gram protein by 45.5%, 41.3%, and 40.6%, respectively. Nutrient restriction from mid-to-late gestation did not influence (P ≥ 0.46) maternal small intestinal protein concentration, or maltase, isomaltase, and lactase activity. Maternal glucoamylase activity per gram intestine increased (P = 0.05) with nutrient restriction by 49.1%. Melatonin supplementation and maternal nutrient restriction did not influence (P ≥ 0.15) fetal small intestinal protein concentration, or glucoamylase, isomaltase, and lactase activity. Maternal nutrient restriction from mid-to-late gestation decreased (P = 0.05) fetal maltase activity per gram intestine by 20.5% but did not influence fetal maltase activity per gram protein. These data indicate that some maternal and fetal carbohydrases are influenced by nutrient restriction and melatonin supplementation in sheep. More information is needed to understand how nutritional and hormonal factors regulate digestive enzyme activity in ruminants to design improved maternal nutrition programs to optimize fetal growth and development while maintaining maternal productivity.

Commercial kefir products assessed for label accuracy of microbial composition and density.

Kefirs are fermented beverages containing yeast and bacteria produced by the fermentation of water or milk with kefir grains. Because microorganism density may influence a product's health benefits, label accuracy regarding viable bacterial density and taxonomy of fermented foods is important. In this study, the microbiota of 5 commercial kefir products were measured quantitatively using standard plating techniques and characterized using high-resolution, long-read 16S rRNA gene amplicon sequencing. To enumerate viable lactic acid bacteria, 2 lots of each product were plated on de Man, Rogosa and Sharpe agar upon opening and following 14 d and incubated under anaerobic and aerobic conditions. Results revealed that 66% of products with a guaranteed count of colony-forming units per gram overstated microorganism density by at least 1 log, with only product E exceeding 1 × 109 cfu/g. Sequencing results demonstrated moderate product label accuracy in regard to taxonomy, yet several products contained bacterial species above the minimum detectable threshold (0.001% relative abundance) that were not included on the labels (e.g., Streptococcus salivarius, Lactobacillus paracasei). Our results demonstrate a moderate level of labeling accuracy for commercial kefir products intended for human consumption. Regulatory agencies and consumers must continue to scrutinize these products and demand a higher level of accuracy and quality.

Effect of feeding a low-vitamin A diet on carcass and production characteristics of steers with a high or low propensity for marbling.

Our research group demonstrated that vitamin A restriction affected meat quality of Angus cross and Simmental steers. Therefore, the aim of this study is to highlight the genotype variations in response to dietary vitamin A levels. Commercial Angus and Simmental steers (n = 32 per breed; initial BW = 337.2 ± 5.9 kg; ~8 months of age) were fed a low-vitamin A (LVA) (1017 IU/kg DM) backgrounding diet for 95 days to reduce hepatic vitamin A stores. During finishing, steers were randomly assigned to treatments in a 2 × 2 factorial arrangement of genotype × dietary vitamin A concentration. The LVA treatment was a finishing diet with no supplemental vitamin A (723 IU vitamin A/kg DM); the control (CON) was the LVA diet plus supplementation with 2200 IU vitamin A/kg DM. Blood samples were collected at three time points throughout the study to analyze serum retinol concentration. At the completion of finishing, steers were slaughtered at a commercial abattoir. Meat characteristics assessed were intramuscular fat concentration, color, Warner-Bratzler shear force, cook loss and pH. Camera image analysis was used for determination of marbling, 12th rib back fat and longissimus muscle area (LMA). The LVA steers had lower (P < 0.001) serum retinol concentration than CON steers. The LVA treatment resulted in greater (P = 0.03) average daily gain than the CON treatment, 1.52 and 1.44 ± 0.03 kg/day, respectively; however, there was no effect of treatment on final BW, DM intake or feed efficiency. Cooking loss and yield grade were greater and LMA was smaller in LVA steers (P < 0.05). There was an interaction between breed and treatment for marbling score (P = 0.01) and percentage of carcasses grading United States Department of Agriculture (USDA) Prime (P = 0.02). For Angus steers, LVA treatment resulted in a 16% greater marbling score than CON (683 and 570 ± 40, respectively) and 27% of LVA Angus steers graded USDA Prime compared with 0% for CON. Conversely, there was no difference in marbling score or USDA Quality Grades between LVA and CON for Simmental steers. In conclusion, feeding a LVA diet during finishing increased marbling in Angus but not in Simmental steers. Reducing the vitamin A level of finishing diets fed to cattle with a high propensity to marble, such as Angus, has the potential to increase economically important traits such as marbling and quality grade without negatively impacting gain : feed or yield grade.

Performance of Standardized Relative CBV for Quantifying Regional Histologic Tumor Burden in Recurrent High-Grade Glioma: Comparison against Normalized Relative CBV Using Image-Localized Stereotactic Biopsies.

BACKGROUND AND PURPOSE: Perfusion MR imaging measures of relative CBV can distinguish recurrent tumor from posttreatment radiation effects in high-grade gliomas. Currently, relative CBV measurement requires normalization based on user-defined reference tissues. A recently proposed method of relative CBV standardization eliminates the need for user input. This study compares the predictive performance of relative CBV standardization against relative CBV normalization for quantifying recurrent tumor burden in high-grade gliomas relative to posttreatment radiation effects. MATERIALS AND METHODS: We recruited 38 previously treated patients with high-grade gliomas (World Health Organization grades III or IV) undergoing surgical re-resection for new contrast-enhancing lesions concerning for recurrent tumor versus posttreatment radiation effects. We recovered 112 image-localized biopsies and quantified the percentage of histologic tumor content versus posttreatment radiation effects for each sample. We measured spatially matched normalized and standardized relative CBV metrics (mean, median) and fractional tumor burden for each biopsy. We compared relative CBV performance to predict tumor content, including the Pearson correlation (r), against histologic tumor content (0%-100%) and the receiver operating characteristic area under the curve for predicting high-versus-low tumor content using binary histologic cutoffs (≥50%; ≥80% tumor). RESULTS: Across relative CBV metrics, fractional tumor burden showed the highest correlations with tumor content (0%-100%) for normalized (r = 0.63, P < .001) and standardized (r = 0.66, P < .001) values. With binary cutoffs (ie, ≥50%; ≥80% tumor), predictive accuracies were similar for both standardized and normalized metrics and across relative CBV metrics. Median relative CBV achieved the highest area under the curve (normalized = 0.87, standardized = 0.86) for predicting ≥50% tumor, while fractional tumor burden achieved the highest area under the curve (normalized = 0.77, standardized = 0.80) for predicting ≥80% tumor. CONCLUSIONS: Standardization of relative CBV achieves similar performance compared with normalized relative CBV and offers an important step toward workflow optimization and consensus methodology.