Algin/Calcium Gels in Solid-Muscle Structured Beef Steaks

Alteration of the inherent characteristics of less preferred beef carcass portions to produce products with greater consumer appeal has been the ultimate goal of structured meat research. Consumer acceptance of structured products has been limited because of (1) low retail visibility, (2) diet/health concerns due to salt addition, and (3) undesirable uncooked product appearance due to discoloration and lack of fiber orientation. Development of solid-muscle structured products would alleviate these limitations and the negative influence the less desirable carcass portions have on total carcass value. Efficacy of a binding gel containing various concentrations of algin/calcium (Alg/Ca) and adipic acid (Ad) that will function between large meat pieces in both raw, refrigerated and cooked states was determined. Results indicated large muscle pieces could be bound by Alg/Ca/Ad gels in both states. Optimum levels could not be recommended since juncture success and binding strength were maximized at the highest Alg/Ca levels and Ad levels used had no effect on these two traits. In the second phase, consumer acceptability of four ty pes of beef steaks fabricated from various muscles in the forequarter were measured. Steak types included (1) ribeye roll steaks, (2) serratus ventralis solid-muscle structured steaks, (3) salt/phosphate comminuted structured steaks, and (4) algin /calcium comminuted structured steaks. Primary meat purchasers rated each type of uncooked steak on fat content, surface discoloration, color and overall desirabi1ity. Each household member over 5 years old completed a sensory evaluation, rating each steak type for tenderness, juiciness, flavor desirability and overall desirability. Laboratory evaluations included proximate analyses, cooking loss, Warner-Bratzler shear and oxidative rancidity after frozen storage. Consumer sensory acceptability was evident for all four steak types, but primary meat purchasers preferred the color, lack of surface discoloration and overall appearance of intact muscle steaks over comminuted structured steaks. Intact muscle steaks received lower sensory tenderness ratings and higher flavor desirability scores than comminuted structured steaks. Viable merchandising options for the beef forequarter, particularly the chuck, are available with new structuring technology

Quasi-Exact Helical Cone Beam Reconstruction for Micro CT

A cone beam micro-CT system is set up to collect truncated helical cone beam data. This system includes a micro-focal X-ray source, a precision computer-controlled X-Y-Z-theta stage, and an image-intensifier coupled to a large format CCD detector. The helical scanning mode is implemented by rotating and translating the stage while keeping X-ray source and detector stationary. A chunk of bone and a mouse leg are scanned and quasi-exact reconstruction is performed using the approach proposed in J. Hu et al. (2001). This approach introduced the original idea of accessory paths with upper and lower virtual detectors having infinite axial extent. It has a filtered backprojection structure which is desirable in practice and possesses the advantages of being simple to implement and computationally efficient compared to other quasi-exact helical cone beam algorithms for the long object problem

Quantification of Pulmonary Arterial Wall Distensibility Using Parameters Extracted from Volumetric Micro-CT Images

Stiffening, or loss of distensibility, of arterial vessel walls is among the manifestations of a number of vascular diseases including pulmonary arterial hypertension. We are attempting to quantify the mechanical properties of vessel walls of the pulmonary arterial tree using parameters derived from high-resolution volumetric x-ray CT images of rat lungs. The pulmonary arterial trees of the excised lungs are filled with a contrast agent. The lungs are imaged with arterial pressures spanning the physiological range. Vessel segment diameters are measured from the inlet to the periphery, and distensibilities calculated from diameters as a function of pressure. The method shows promise as an adjunct to other morphometric techniques such as histology and corrosion casting. It possesses the advantages of being nondestructive, characterizing the vascular structures while the lungs are imaged rapidly and in a near-physiological state, and providing the ability to associate mechanical properties with vessel location in the intact tree hierarchy

SPECT Imaging of Pulmonary Blood Flow in a Rat

Small animal imaging is experiencing rapid development due to its importance in providing high-throughput phenotypic data for functional genomics studies. We have developed a single photon emission computed tomography (SPECT) system to image the pulmonary perfusion distribution in the rat. A standard gamma camera, equipped with a pinhole collimator, was used to acquire SPECT projection images at 40 sec/view of the rat thorax following injection of Tc99m labeled albumin that accumulated in the rat\u27s lungs. A voxel-driven, ordered-subset expectation maximization reconstruction was implemented. Following SPECT imaging, the rat was imaged using micro-CT with Feldkamp conebeam reconstruction. The two reconstructed image volumes were fused to provide a structure/function image of the rat thorax. Reconstruction accuracy and performance were evaluated using numerical simulations and actual imaging of an experimental phantom consisting of Tc99m filled chambers with known diameters and count rates. Full-width half-maximum diameter measurement errors decreased with increasing chamber diameter, ranging from \u3c 6% down to 0.1%. Errors in the ratio of count rate estimates between tubes were also diameter dependent but still relatively small. This preliminary study suggests that SPECT will be useful for imaging and quantifying the pulmonary blood flow distribution and the distribution of Tc99m labeled ligands in the lungs of small laboratory animals

Micro-CT Image-Derived Metrics Quantify Arterial Wall Distensibility Reduction in a Rat Model of Pulmonary Hypertension

We developed methods to quantify arterial structural and mechanical properties in excised rat lungs and applied them to investigate the distensibility decrease accompanying chronic hypoxia-induced pulmonary hypertension. Lungs of control and hypertensive (three weeks 11% O2) animals were excised and a contrast agent introduced before micro-CT imaging with a special purpose scanner. For each lung, four 3D image data sets were obtained, each at a different intra-arterial contrast agent pressure. Vessel segment diameters and lengths were measured at all levels in the arterial tree hierarchy, and these data used to generate features sensitive to distensibility changes. Results indicate that measurements obtained from 3D micro-CT images can be used to quantify vessel biomechanical properties in this rat model of pulmonary hypertension and that distensibility is reduced by exposure to chronic hypoxia. Mechanical properties can be assessed in a localized fashion and quantified in a spatially-resolved way or as a single parameter describing the tree as a whole. Micro-CT is a nondestructive way to rapidly assess structural and mechanical properties of arteries in small animal organs maintained in a physiological state. Quantitative features measured by this method may provide valuable insights into the mechanisms causing the elevated pressures in pulmonary hypertension of differing etiologies and should become increasingly valuable tools in the study of complex phenotypes in small-animal models of important diseases such as hypertension

Effects of Anabolic Implants and Breed Group on Carcass Traits and Palatability Characteristics of Bullock Beef

The ultimate goal of the beef industry is efficient production of beef that satisfies the consumer and increases demand. In the past, American producers have been primarily interested in the production of high quality beef because consumers were concerned with meat palatability, particularly tenderness. However, due to current diet-health issues and economic conditions, American consumers have come to expect acceptable palatability and are now more concerned with the nutrient density and cost of their meat purchases. Maximum production efficiency must be realized to keep beef competitive with other protein sources for consumer dollars. Production systems must be used that are capable of producing more lean beef per animal on less feed without sacrificing palatability. Since the ratio between feed costs for gains of fat and muscle is about 7 to 1, the over-fattening of an animal in an effort to obtain more tender meat is no longer economically feasible. Anabolic agents in the form of subcutaneous implants have been used since the early 1950\u27s to increase the production efficiency of slaughter beef cattle. Implants have been developed for steers and heifers that have led to improvements of about 15% in growth rate and about 10% in fed conversion efficiency. Success with these growth-promoting compounds has been shown particularly in intensive rearing situations. One of the greatest immediate opportunities available to the beef industry for reducing production costs is. the producing, feeding and marketing of intact males. Research discussed later indicates intact males grow more rapidly, utilize feed more efficiently and produce a higher yielding carcass (more retail product) with less fat and more muscle than castrates. Although intact males increase production efficiency, considerable resistance in traditional marketing channels has been encountered for beef from young, intact males. Seideman et al. indicated young bulls have a low packer acceptance because of difficult hide removal, heavy carcass weights and low USDA quality grades. The authors also suggested packer unacceptability has been associated with the belief that beef from bulls has lower consumer acceptance at the retail level because of differences in color, texture and fat distribution. In addition, cooked meat from intact males is often less tender than steer beef. In one such study, Forrest concluded no benefits accrue from implanting young bulls with progesterone-estradiol in terms of growth rate, feed efficiency or lean content. The objectives of this study were to determine the effects of implanted anabolic agents on the cutability and quality of carcasses from intact males of two breed groups and to study the sensory traits of beef derived from these intact males

Gapless spin-liquid state in the structurally disorder-free triangular antiferromagnet NaYbO2_2

We present the structural characterization and low-temperature magnetism of the triangular-lattice delafossite NaYbO$_2$. Synchrotron x-ray diffraction and neutron scattering exclude both structural disorder and crystal-electric-field randomness, whereas heat-capacity measurements and muon spectroscopy reveal the absence of magnetic order and persistent spin dynamics down to at least 70\,mK. Continuous magnetic excitations with the low-energy spectral weight accumulating at the $K$-point of the Brillouin zone indicate the formation of a novel spin-liquid phase in a triangular antiferromagnet. This phase is gapless and shows a non-trivial evolution of the low-temperature specific heat. Our work demonstrates that NaYbO$_2$ practically gives the most direct experimental access to the spin-liquid physics of triangular antiferromagnets.Comment: 6 pages, 4figure

A millimeter-wave kinetic inductance detector camera for long-range imaging through optical obscurants

Millimeter-wave imaging provides a promising option for long-range target detection through optical obscurants such as fog, which often occur in marine environments. Given this motivation, we are currently developing a 150 GHz polarization-sensitive imager using a relatively new type of superconducting pair-breaking detector, the kinetic inductance detector (KID). This imager will be paired with a 1.5 m telescope to obtain an angular resolution of 0.09° over a 3.5° field of view using 3,840 KIDs. We have fully characterized a prototype KID array, which shows excellent performance with noise strongly limited by the irreducible fluctuations from the ambient temperature background. Full-scale KID arrays are now being fabricated and characterized for a planned demonstration in a maritime environment later this year