LIPIDS IN SUBCUTANEOUS TISSUES AND LONGISSIMUS MUSCLES OF FEEDLOT AND GRASS-FED EWES1

Subcutaneous and intramuscular lipids from feedlot-and grass-fed ewes were studied to determine if diet would influence fatty acid composition of these older animals. Subcutaneous lipid of ewes from the feedlot-fed group contained more 4-methyl branched acids, less iso and anteiso branched acids, less stearic acid and more octadecenoic acid than grass-fed ewes. Only small amounts of medium chain acids (10–15 carbons) were noted in longissimus muscle lipids from both dietary groups and essentially all of them were in the triglycerides. Lipids in longissimus muscle of feedlot ewes contained more monounsaturated and less polyunsaturated acids and this was due to higher levels of triglycerides in longissimus lipid of feedlot-fed ewes. Approximately three times as much high melting stearic acid was present in subcutaneous lipid of both dietary groups of ewes as has been noted in subcutaneous lipid of lambs. Reduction of high melting stearic acid in mutton fat by a short grain feeding period should make mutton more acceptable.     

DEPOSITION OF SUBMICRON AEROSOL PARTICLES DURING INTEGRATED CIRCUIT MANUFACTURING: THEORY

ABSTRACT

Submicron (≤1μm) particle contamination can produce unacceptably low yields in the manufacture of integrated circuits. Calculations were made to predict deposition velocities of 0·01-lOμm particles, incorporating gravitational, dlffusional, and electrostatic effects. The results were summarized in equations that correlate non-dimensional deposition (Sherwood number) with convective-diffusion (Peclet number) and with electrostatics (Boltzmann and Fuchs charge distributions). These equations were used In conjunction with particle size distributions to predict particle deposition. In a companion paper |25| the predictions were shown to compare well with limited experimental data. To reduce deposition product surfaces should not be electrically charged and, where possible, these surfaces should be at higher temperatures than the ambient gas. For quality control purposes, the deposition flux predictions could serve to link the specifications of gas cleanliness with the specifications of surface cleanliness.     

DIFFUSIONAL RELEASE OF WATER-SOLUBLE BIOACTIVE AGENTS FROM ETHYLENE-VINYL ACETATE COPOLYMERS

A model is presented for the diffusional release of theophylline and albumin from ethylene-vinyl acetate based polymeric systems with dynamically changing porosity. The model may be used to predict values of tortuosity of certain types of controlled drug delivery polymeric systems if drug dissolution limitations are negligible. The values of the tortuosity factor calculated indicate that small constrictions between large pores play an important role in the solute release behavior from these samples.     

Software image alignment for X-ray microtomography with submicrometre resolution using a SEM-based X-ray microscope

Improved X-ray sources and optics now enable X-ray imaging resolution down to ∼50 nm for laboratory-based X-ray microscopy systems. This offers the potential for submicrometre resolution in tomography; however, achieving this resolution presents challenges due to system stability. We describe the use of software methods to enable submicrometre resolution of approximately 560 nm. This is a very high resolution for a modest laboratory-based point-projection X-ray tomography system. The hardware is based on a scanning electron microscope, and benefits from inline X-ray phase contrast to improve visibility of fine features. Improving the resolution achievable with the system enables it to be used to address a greater range of samples.     

Production planning and control II. The planning horizon problem

A general model of the production planning and control problem based on modern control theory is given, This model is used to develop principles for planning under uncertainty and to illustrate the strong connection between the structure of the production-inventory system, the characteristics of the environment, and the planning horizon. It is shown that the planning horizon is a function of the structure of both the production-inventory system and the market dynamics. Further, it is shown that the planning horizon is independent of the level of uncertainty and that the planning horizon problem is effectively decoupled from the problems of measuring the state of the production-inventory system and market forecasting.     

Production planning and control III. The sampling problem

Concepts from bayesian decision theory and control theory are combined to address the question of how long a decision-maker should wait between samples of the stale of a dynamic production system. Expressions defining expected performance are derived for open-loop, continuous, and sampled information modes of operation. These results are used to define the value of sampled information. The main results support the intuition of decision-makers and serve as qualitative guides for information system design.     

PHYSICAL CHARACTERISTICS OF BEEF ROASTS PREPARED WITH DIFFERENT FOODSERVICE COOKING METHODS

Effects of cooking rate, fat trim level, aging period, endpoint temperature and oven type (conventional, forced air convection and forced air/steam combination) on yield, composition and cooking parameters for eight types of beef roasts were investigated. Generally, fast cooking, higher endpoint temperatures, complete removal of external fat and the use of forced air/steam combination ovens increased cooking losses. Fast cooking rates and forced air/steam combination ovens increased moisture loss in some roasts. Reduced levels of external fat did not dramatically affect yields or relative changes in composition due to cooking, but did increase cooking time per unit weight. Forced air/steam combination ovens may reduce the required length of preparation per unit raw weight while conventional ovens may increase cooking time. Rapid cooking of larger roasts with moist heat increased postcooking temperature rise. These results should aid in the revision of foodservice beef cookery guidelines.     

COMPOSITION,WATER-HOLDING CAPACITY AND pH OF MUSCLES FROM PIGS SUPPLEMENTED WITH PORCINE SOMATOTROPIN (pSt)1

Eighteen pigs were injected with one of three levels of recombinant porcine somatotropin (pSt) and received no more injections 7 days before slaughter. Excised triceps brachii, psoas major, semimembranosus, semitendinosus and biceps femoris muscles were analyzed for crude fat, moisture and protein contents, pH and water-holding capacity, Generally, raw muscles from somatotropin-supplemented pigs contained less crude fat than did muscles from control animals. The crude fat content of the broiled triceps brachii and roasted biceps femoris decreased in response to somatotropin supplementation. Muscles from supplemented and unsupplemented pigs did not differ in cooked muscle moisture or protein contents, raw or cooked pH or raw muscle water holding capacity.