Influence of the Ruminant Digestive Process on the Germinability of Range Forage Species

Ingestion and dispersal of seeds of desirable species by domestic livestock is potentially important as a range improvement practice, but the passage of seed by livestock has only been studied in a fragmented way, particularly for species adapted to rangelands of western North America. The objectives of this research were to examine the effects of different periods of exposure to in vitro and in vivo digestion processes in cattle on the germinability of several grass species, and determine if the in vitro incubation technique is a good predictor of seed fate following passage through the ruminant digestive tract. Seeds of 13 grass species adapted to the Intermountain West were exposed to in vitro incubation for 24, 48, and 72 hours, and then tested for germination at an optimal temperature regime (10°C night/20°C day) in a controlled environment chamber. Germination responses varied considerably among grass species with changes in length of exposure to in vitro incubation, but germination decreased for incubated seed compared to untreated seed for all species. Five species with the highest germination in in vitro incubation trials were fed to Holstein steers in in vivo digestion trials. Approximately 20% of the ingested seeds were recovered for all species 6 days after feeding, and the highest recovery occurred 2 and 3 days after feeding. Germination of undamaged, recovered seeds decreased as passage time through the digestive tract increased. Of the species tested, seeds of Psathyrostachys juncea, Thinopyrum ponticum, Agropyron cristatum X A. desertorum, and Elytrigia repens X Pseudoroegneria spicata have the greatest potential to survive passage through the digestive tract and germinate in appreciable numbers. The in vitro incubation technique may be used as a crude indicator of seed fate following passage through the digestive tract

Effect of Moulding Temperature on Mechanical Properties of Pure Aluminum Sand Casting

In this study, mechanical properties (Tensile test, Brinell hardness and microstructure analysis) of pure aluminium after sand casting were investigated. Tensile test, Brinell hardness and microstructure analysis were performed using MAX text software, Universal Testing Machine and Escope with Clemax Imager, respectively. Sand cast aluminium was observed to have good tensile and hardness properties. From the observations, sand cast sample had uniform distribution of aluminium. &nbsp

Heat affected zones and oxidation marks in fiber laser-oxygen cutting of mild steel

The effect of cutting speed and sheet thickness on surface oxidation and heat affected zones (HAZs) has been investigated for laser-oxygen cutting of mild steel sheet with a fiber laser. Optical and scanning electron micrographs were used to determine the extent of surface oxidation and HAZ from plan and cross-sectional views, respectively. The HAZ is consistently wider at the bottom of the cut compared to the HAZ at the top of the cut. With increasing speed, the width of the HAZ at the top of the cut decreases whereas the HAZ width at the bottom of the cut generally increases. No simple, direct relationship between HAZ width and surface oxidation was seen. However, it is possible to state that in each case considered here, the HAZ would be completely removed if they are machined back by a depth equal to the extent of the surface oxidation. (C) 2011 Laser Institute of America

Fibre laser piercing of mild steel: the effects of power intensity, gas type and pressure

Laser piercing is used to generate a starting point for laser cutting. The pierced hole is normally larger than the kerf width, which means that it cannot lie on the cut line. An experimental program investigating the piercing process as a function of laser and assist gas parameters is presented. An Nd:YAG fibre laser with a maximum power of 2 kW was used in continuous wave mode to pierce holes in 2 mm thick mild steel. Oxygen and nitrogen were used as assist gases, with pressures ranging from 0.3 to 12 bar. The sizes, geometries and piercing time of the holes produced have been analysed. The pierced hole size decreases with increasing gas pressure and increasing laser power. Oxygen assist gas produced larger diameter holes than nitrogen. A new technique is presented which produces pierced holes no larger than the kerf with and would allow the pierced hole to lie on the cut line of the finished product – allowing better material usage. This uses an inclined jet of nitrogen when piercing prior to oxygen assisted cutting

Fibre laser cutting of thin section mild steel: an explanation of the 'striation free' effect

This paper presents the results of an experimental and theoretical investigation into the phenomenon of 'striation free cutting', which is a feature of fibre laser/oxygen cutting of thin section mild steel. The paper concludes that the creation of very low roughness edges is related to an optimisation of the cut front geometry when the cut front is inclined at angles close to the Brewster angle for the laser-material combination

Oxamniquine resistance alleles are widespread in Old World Schistosoma mansoni and predate drug deployment

Do mutations required for adaptation occur de novo, or are they segregating within populations as standing genetic variation? This question is key to understanding adaptive change in nature, and has important practical consequences for the evolution of drug resistance. We provide evidence that alleles conferring resistance to oxamniquine (OXA), an antischistosomal drug, are widespread in natural parasite populations under minimal drug pressure and predate OXA deployment. OXA has been used since the 1970s to treat Schistosoma mansoni infections in the New World where S. mansoni established during the slave trade. Recessive loss-of-function mutations within a parasite sulfotransferase (SmSULT-OR) underlie resistance, and several verified resistance mutations, including a deletion (p.E142del), have been identified in the New World. Here we investigate sequence variation in SmSULT-OR in S. mansoni from the Old World, where OXA has seen minimal usage. We sequenced exomes of 204 S. mansoni parasites from West Africa, East Africa and the Middle East, and scored variants in SmSULT-OR and flanking regions. We identified 39 non-synonymous SNPs, 4 deletions, 1 duplication and 1 premature stop codon in the SmSULT-OR coding sequence, including one confirmed resistance deletion (p.E142del). We expressed recombinant proteins and used an in vitro OXA activation assay to functionally validate the OXA-resistance phenotype for four predicted OXA-resistance mutations. Three aspects of the data are of particular interest: (i) segregating OXA-resistance alleles are widespread in Old World populations (4.29–14.91% frequency), despite minimal OXA usage, (ii) two OXA-resistance mutations (p.W120R, p.N171IfsX28) are particularly common (>5%) in East African and Middle-Eastern populations, (iii) the p.E142del allele has identical flanking SNPs in both West Africa and Puerto Rico, suggesting that parasites bearing this allele colonized the New World during the slave trade and therefore predate OXA deployment. We conclude that standing variation for OXA resistance is widespread in S. mansoni

Perspectives on Immunoglobulins in Colostrum and Milk

Immunoglobulins form an important component of the immunological activity found in milk and colostrum. They are central to the immunological link that occurs when the mother transfers passive immunity to the offspring. The mechanism of transfer varies among mammalian species. Cattle provide a readily available immune rich colostrum and milk in large quantities, making those secretions important potential sources of immune products that may benefit humans. Immune milk is a term used to describe a range of products of the bovine mammary gland that have been tested against several human diseases. The use of colostrum or milk as a source of immunoglobulins, whether intended for the neonate of the species producing the secretion or for a different species, can be viewed in the context of the types of immunoglobulins in the secretion, the mechanisms by which the immunoglobulins are secreted, and the mechanisms by which the neonate or adult consuming the milk then gains immunological benefit. The stability of immunoglobulins as they undergo processing in the milk, or undergo digestion in the intestine, is an additional consideration for evaluating the value of milk immunoglobulins. This review summarizes the fundamental knowledge of immunoglobulins found in colostrum, milk, and immune milk

The Effecting Factors in The Mass Media in the Sultanate of Oman: A field study on Omani Journalists

The Effecting Factors in The Mass Media in the Sultanate of Oman: A field study on Omani Journalists This study aimed to look into the most important factors that affect the media in Oman; such as the Press and Publications Law (1984), Finance and Advertising as well as social environments such as cultural aspects. In order to answer the study questions, the researcher applied a questionnaire to more than 200 media professionals to find out journalists’ attitudes towards obstacles affecting media content in newsrooms within media establishments in the country The study concluded that; the Press and Publications law control all mass media content. Findings from the questionnaire points that this law is no longer suitable for the media in Oman, which has witnessed some development in recent years. Journalists’ self-censorship is one of the most serious problem affecting the development of the Omani media The study reveals a lack of adequate salary of broadcasters and journalists The study also points that local newspapers dedicate more space for advertising rather than cultural articles. The study found that social environments such as cultural aspects, perspectives towards media professionals do not create a good media-working environment in Oman.

Fibre laser cutting of thin section mild steel

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Separation of antimicrobial protein fractions from animal resources for potential use in infant feeding

In the first part of this study, a non-ferric method for selective elimination of β-lactoglobulin from cheese whey was investigated. A new method was developed based on hexametaphosphate treatment of cheese whey. When Cheddar cheese whey was treated under the optimized conditions, i.e., 1.33 mg/mL sodium hexametaphosphate at 22°C and pH 4.07 for 1 hr, more than 80% of β-lactoglobulin was removed by precipitation. Almost all of the immunoglobulins and the major portion of α-lactalbumin were retained in the supernatant as indicated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunochemical assays. By dialysis against distilled water 72.2% of the phosphorus was removed from the supernatant. In the second and the third part of the thesis, chromatographic methods were used for isolation of immunoglobulins and lactoferrin from whey proteins. By using gel filtration on Sephacryl S-300, 99, 83.3 and 92.1% biologically active immunoglobulin G were obtained for colostral whey, acid and Cheddar cheese whey, respectively. Lactoferrin, selectively adsorbed to the heparin-attached Sepharose, was eluted with 5 mM Veronal-HC1 containing 0.5M NaC1, at pH 7.2. 1,4-Butanediol diglycidyl ether-iminodiacetic acid on Sepharose 6B, or so-called metal chelate-interaction chromatography (MCIC), was loaded with copper ion and used for the same purpose. Of the two peaks obtained, the first yellowish peak was rich in lactoferrin, while the second peak was rich in immunoglobulins. Some of the physical and chemical properties of the proteins in these peaks, including immunochemical properties, isoelectric points, binding to bacterial lipopolysaccharides, and the mechanism of protein-metal interaction via histidine modification, and the capacity of the method were studied. The possibility of isolating immunoglobulins and lactoferrin from electrodialyzed whey was also investigated. In the fourth, fifth and sixth parts of the thesis, the method developed for isolation of immunoglobulins and lactoferrin from whey protein was applied to isolate these biologically important proteins directly from skimmilk, blood and egg white. The casein in skimmilk was found to compete with immunoglobulins for binding to copper ion in MCIC column when skimmilk was loaded in presence of 0.05 M Tris-acetate buffer containing 0.5 M NaC1, pH 8.2; however, this problem was solved by changing the equilibrating buffer to 0.02 M phosphate buffer containing 0.5 M NaC1, pH 7.0. When blood was directly applied to MCIC column, the yield of biologically active IgG was more than 95%. Ovotransferrin, strongly adsorbed to the MCIC column, was eluted with two-step elution protocols which suggests it exists in two forms. The histidine residues in immunoglobulins, caseins, transferrin and ovotransferrin were found to be involved in the mechanism of the interaction with the MCIC column.Land and Food Systems, Faculty ofGraduat