71 research outputs found
Comparison of the emissions of current expendable launch vehicles and future spaceplanes
This paper compares the environmental impact of two types of launch vehicles, an expendable vertical launcher (Delta IV) and a conceptual SSTO spaceplane. A realistic trajectory for the spaceplane is generated using a multiple-shooting trajectory optimisation method, which integrates physical models and generates an optimal control law minimising the fuel consumption and the emissions of the flight. These were compared with the emissions from a standard Delta IV trajectory. The launch was to a 200 km circular LEO at 27.5° inclination. The chemical investigated is H2O, which contributes to the depletion of the ozone layer in the stratosphere. The study shows that for the ascent trajectory the spaceplane produces a total of 5.0143 x 105 kg of H2O, compared with 2.24 x 105 kg for the Delta IV. The spaceplane has a peak production altitude in the sensitive lower stratosphere, compared to the much lower peak production altitude of the Delta IV
Increasing the Value of the Round and Sirloin Through Pre-Rigo Skeletal Separations
Thirty crossbred steers were utilized to explore and compare tenderness improvements in beef round and sirloin muscles resulting from various methods of pre-rigor skeletal separations. Animals were slaughtered according to industry procedures and at 60 min postmortem one of six treatments were randomly applied to each side: A) control, B) saw pelvis at the sirloin-round junction, C) separate the pelvic-femur joint, D) saw femur at mid-point, E) combination of B and C, and F) combination of B and D. After 48-h, the following muscles were excised from each side: semimembranosis (SM), biceps femoris (BF-R), semitendinosis (ST), and adductor (AD) from the round; vastus lateralis (VL) and rectus femoris (RF) from the knuckle; and gluteus medius (GM), biceps femoris (BF-S) and psoas major (PM) from the sirloin. Following a 10 d ageing period, samples were removed from each muscle to determine the effect of treatments on sarcomere length and Warner-Bratzler shear force. Sarcomere lengths differed between treatments for SM, AD, ST, GM, and PM. Treatment C resulted in longer sarcomeres than controls for SM, AD, and ST. All pre-rigor skeletal separation treatments yielded shorter sarcomeres for the PM as compared to controls. Warner-Bratzler shear force differed between treatments for RF, ST and PM. For RF, all treatments, except B, resulted in lower (P \u3c 0.05) shear values than for controls. Treatment F resulted in higher shear force values for the PM than controls (P \u3c 0.05). Also, treatments B, D, and F increased shear force of the ST relative to controls (P \u3c 0.05). Correlations between sarcomere length and shear force were found to be low and quite variable between muscles. In general, treatments increased sarcomere length of several muscles from the sirloin/round region, but had mixed effects on shear force values
Intramuscular Tenderness Variation Within Four Muscles of the Beef Chuck
To evaluate the potential for steak production from beef chuck muscles, we evaluated intramuscular tenderness variation within four beef chuck muscles: infraspinatus (IF), supraspinatus (SS), triceps brachii (TB), and serratus ventralis (SV). The IF, SS, TB, and SV muscles were cut into 1-in-thick steaks perpendicular to the long axis of the muscle. An identification tag was placed on each steak consisting of a muscle identification number, steak number, and orientation of the steak. Steaks were vacuum-packaged and stored at -8° F until used. Steaks were thawed at 34° F and broiled on electric broilers to an internal temperature of 160° F (medium degree of doneness). One core was removed from each square inch section parallel to the muscle fiber and sheared once to determine Warner Bratzler shear (WBS) force. The SS had an overall WBS force mean of 11.97 lb with no tenderness difference (P \u3e 0.05) among steak locations. The IF had an overall WBS force mean of 6.97 lb with no tenderness difference (P \u3e 0.05) among steak locations. The SV had a mean WBS force value of 9.64 lb with significant tenderness variation among steak locations. These tenderness variations were dispersed throughout the SV in no particular pattern. The TB had a mean WBS force value of 9.08 lb with significant tenderness variation among steak locations. The TB had lower (P \u3c 0.05) shear force in the middle region of the muscle with the distal and proximal ends being tougher (P \u3c 0.05). The data presented in this study provides a reasonably detailed mapping of the tenderness regions within the IF, SS, TB, and SV muscles. This information could be utilized to add value to the beef chuck through alternative fabrication and marketing of the muscles to fabricate steaks from consistently tender regions
Advances in POST2 End-to-End Descent and Landing Simulation for the ALHAT Project
Program to Optimize Simulated Trajectories II (POST2) is used as a basis for an end-to-end descent and landing trajectory simulation that is essential in determining design and integration capability and system performance of the lunar descent and landing system and environment models for the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. The POST2 simulation provides a six degree-of-freedom capability necessary to test, design and operate a descent and landing system for successful lunar landing. This paper presents advances in the development and model-implementation of the POST2 simulation, as well as preliminary system performance analysis, used for the testing and evaluation of ALHAT project system models
The 10th Biennial Hatter Cardiovascular Institute workshop: cellular protection—evaluating new directions in the setting of myocardial infarction, ischaemic stroke, and cardio-oncology
Due to its poor capacity for regeneration, the heart is particularly sensitive to the loss of contractile cardiomyocytes. The onslaught of damage caused by ischaemia and reperfusion, occurring during an acute myocardial infarction and the subsequent reperfusion therapy, can wipe out upwards of a billion cardiomyocytes. A similar program of cell death can cause the irreversible loss of neurons in ischaemic stroke. Similar pathways of lethal cell injury can contribute to other pathologies such as left ventricular dysfunction and heart failure caused by cancer therapy. Consequently, strategies designed to protect the heart from lethal cell injury have the potential to be applicable across all three pathologies. The investigators meeting at the 10th Hatter Cardiovascular Institute workshop examined the parallels between ST-segment elevation myocardial infarction (STEMI), ischaemic stroke, and other pathologies that cause the loss of cardiomyocytes including cancer therapeutic cardiotoxicity. They examined the prospects for protection by remote ischaemic conditioning (RIC) in each scenario, and evaluated impasses and novel opportunities for cellular protection, with the future landscape for RIC in the clinical setting to be determined by the outcome of the large ERIC-PPCI/CONDI2 study. It was agreed that the way forward must include measures to improve experimental methodologies, such that they better reflect the clinical scenario and to judiciously select combinations of therapies targeting specific pathways of cellular death and injury
National Beef Tenderness Survey—2022: Consumer Sensory Panel Evaluations and Warner-Bratzler Shear Force of Beef Steaks From Retail and Foodservice
Beef retail steaks from establishments across 11 US cities and beef foodservice steaks from establishments in 6 US cities were evaluated by consumer sensory evaluations and Warner-Bratzler shear (WBS) force analyses. The retail tenderloin had the lowest (P<0.05) WBS force value compared to other retail cuts. The retail steak with the greatest (P<0.05) WBS force value was the top sirloin. Foodservice ribeye and top loin steaks had greater (P<0.05) WBS force values compared to the tenderloin. All retail top blade, bone-in ribeye, Porterhouse, and tenderloin steaks were categorized as“very tender” (<31.4 N). There were no (P>0.05) differences in WBS force values among USDA quality grade groups for foodservice steaks. Retail tenderloin steaks received the highest (P<0.05) consumer rating for overall like/dislike, tenderness like/dislike,tenderness level, flavor like/dislike, and juiciness like/dislike compared to all other retail cuts. There were no (P>0.05)differences among the 4 foodservice cuts for consumer sensory ratings of overall like/dislike, tenderness like/dislike, tenderness level, flavor like/dislike, and juiciness like/dislike. There were no (P>0.05) USDA quality grade differences for ribeye, top loin, top sirloin, and tenderloin foodservice steaks for overall like/dislike, tenderness like/dislike, tenderness level, flavor like/dislike, and juiciness like/dislike. Regardless of source (foodservice or retail), USDA grade group, or beef cut, measures of tenderness in this survey reveal ratings and values that should meet most consumer expectations in the marketplace
Changes in Mood States and Biomarkers During Peginterferon and Ribavirin Treatment of Chronic Hepatitis C
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74953/1/j.1572-0241.2008.02106.x.pd
Chronic Exposure to the Herbicide, Atrazine, Causes Mitochondrial Dysfunction and Insulin Resistance
There is an apparent overlap between areas in the USA where the herbicide, atrazine (ATZ), is heavily used and obesity-prevalence maps of people with a BMI over 30. Given that herbicides act on photosystem II of the thylakoid membrane of chloroplasts, which have a functional structure similar to mitochondria, we investigated whether chronic exposure to low concentrations of ATZ might cause obesity or insulin resistance by damaging mitochondrial function. Sprague-Dawley rats (n = 48) were treated for 5 months with low concentrations (30 or 300 µg kg−1 day−1) of ATZ provided in drinking water. One group of animals was fed a regular diet for the entire period, and another group of animals was fed a high-fat diet (40% fat) for 2 months after 3 months of regular diet. Various parameters of insulin resistance were measured. Morphology and functional activities of mitochondria were evaluated in tissues of ATZ-exposed animals and in isolated mitochondria. Chronic administration of ATZ decreased basal metabolic rate, and increased body weight, intra-abdominal fat and insulin resistance without changing food intake or physical activity level. A high-fat diet further exacerbated insulin resistance and obesity. Mitochondria in skeletal muscle and liver of ATZ-treated rats were swollen with disrupted cristae. ATZ blocked the activities of oxidative phosphorylation complexes I and III, resulting in decreased oxygen consumption. It also suppressed the insulin-mediated phosphorylation of Akt. These results suggest that long-term exposure to the herbicide ATZ might contribute to the development of insulin resistance and obesity, particularly where a high-fat diet is prevalent
Global Phylogeography with Mixed-Marker Analysis Reveals Male-Mediated Dispersal in the Endangered Scalloped Hammerhead Shark (Sphyrna lewini)
Background: The scalloped hammerhead shark, Sphyrna lewini, is a large endangered predator with a circumglobal distribution, observed in the open ocean but linked ontogenetically to coastal embayments for parturition and juvenile development. A previous survey of maternal (mtDNA) markers demonstrated strong genetic partitioning overall (global W ST = 0.749) and significant population separations across oceans and between discontinuous continental coastlines. Methodology/Principal Findings: We surveyed the same global range with increased sample coverage (N = 403) and 13 microsatellite loci to assess the male contribution to dispersal and population structure. Biparentally inherited microsatellites reveal low or absent genetic structure across ocean basins and global genetic differentiation (FST = 0.035) over an order of magnitude lower than the corresponding measures for maternal mtDNA lineages (W ST = 0.749). Nuclear allelic richness and heterozygosity are high throughout the Indo-Pacific, while genetic structure is low. In contrast, allelic diversity is low while population structure is higher for populations at the ends of the range in the West Atlantic and East Pacific. Conclusions/Significance: These data are consistent with the proposed Indo-Pacific center of origin for S. lewini, and indicate that females are philopatric or adhere to coastal habitats while males facilitate gene flow across oceanic expanses. This study includes the largest sampling effort and the most molecular loci ever used to survey the complete range of
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