16 research outputs found
Image Analysis of the Fat Dispersion in a Comminuted Meat System
In a series of experiments on a comminuted meat system, image analyses were conducted to quantify changes in structure as affected by polyphosphate, fat level, and chopping time and temperature. Four batches of comminuted meat were investigated which contained neck beef, pig head meat, rino, ice, salt (2%), fat at a level of either 27 or 40%, and polyphosphate at a level of either 0 or 0. 5%. Structural changes in different stages of comminution coincided with a shift in size distribution, shape factor, density and area percentage of fat particles. The density of the protein matrix (matrix defined as all disintegrated tissues, without intact pieces of muscle fibres, connective tissue and fat cell clusters) was markedly affected by polyphosphate. Polyphosphate led to a fine dispersion of the fat, as reflected by the formation of a larger proportion of fat droplets smaller than 3.5 um2. Results indicate that in meat batters physical entrapment of larger fat particles as well as emulsification of smaller droplets occur simultaneously in the course of fat stabilization
Accuracy and Utility of Sarcomere Length Assessment by Laser Diffraction
In two experiments the computation of sarcomere length from laser diffraction patterns was tested for accuracy against phase-contrast microscopy . Particular attention was paid to methodological factors such as sampling location and computation formulae. Correlation coefficients between the laser diffraction technique and the microscopical method were high (r= 0.96) in both experiments. However, when computed from a simplified formula, the sarcomere length values, determined by laser diffraction patterns tended to be approximately 0. 10 lJm lower. It is recommended to use the correct formula in computing the laser diffraction data and to investigate a limited number of fibres (3) in a sufficiently large number (5) of randomly distributed samples
The Effect of the Crow Hop on Elbow Stress During an Interval Throwing Program
BACKGROUND: Postoperative rehabilitation protocols after ulnar collateral ligament (UCL) reconstruction typically involve a structured interval throwing program. In an effort to minimize torque placed on the UCL, athletes are often instructed to throw with a crow hop, even at short throwing distances. However, the effect of the crow hop on medial elbow stress is unknown.
PURPOSE/HYPOTHESIS: The purpose was to determine whether elbow stress differs with and without a crow hop across the throwing distances of a typical interval throwing program. We hypothesized that crow hop throws would generate lower torque on the elbow than standing throws at each distance of the interval throwing program.
STUDY DESIGN: Controlled laboratory study.
METHODS: Healthy high school and collegiate pitchers and position players were recruited from the surrounding area. Each player was outfitted with a wearable athletic sleeve and device that recorded elbow torque (Newton-meters), arm slot (degrees), arm speed (revolutions per minute), and shoulder rotation (degrees). Ball velocity (miles per hour) was measured using a radar gun. Players were instructed to perform 3 crow hop throws and 3 standing throws at distances of 30, 45, 60, 90, 120, 150, and 180 feet. A repeated measures analysis of variance was used to compare ball velocity, elbow torque, arm slot, arm speed, and shoulder rotation between crow hop and standing throws at each throwing distance.
RESULTS: Twenty athletes participated in this study (average age, 17.8 years; range, 15-25 years). The average medial elbow torque increased at each distance for both crow hop and standing throws at distances of 30, 45, 60, and 90 feet (P \u3c .05), after which there were no significant increases in elbow torque (P \u3e .05). The average torque was higher for crow hop throws than standing throws at distances of 30 feet (13.9 N·m vs 12.0 N·m; P = .002), 45 feet (21.8 N·m vs 19.3 N·m; P = .005), and 60 feet (28.0 N·m vs 24.5 N·m; P = .02).
CONCLUSION: Crow hop throws generated greater medial elbow torque than standing throws at distances up to 60 feet; however, there were no differences in elbow torque at distances greater than 60 feet between the 2 throw types. For both crow hop and standing throws, elbow stress increased at each distance interval up to 90 feet before plateauing at distances greater than 90 feet. The crow hop throwing technique does not reduce medial elbow stress during a simulated interval throwing program, and it may actually increase torque at shorter throwing distances.
CLINICAL RELEVANCE: The results of our study indicate that it would be prudent for players to initially perform standing throws at shorter distances and only later be allowed to employ a natural crow hop at greater distances to minimize torque placed on the medial elbow during UCL rehabilitation protocols
Enhanced antiviral activity of human surfactant protein d by site-specific engineering of the carbohydrate recognition domain
Innate immunity is critical in the early containment of influenza A virus (IAV) infection and surfactant protein D (SP-D) plays a crucial role in innate defense against IAV in the lungs. Multivalent lectin-mediated interactions of SP-D with IAVs result in viral aggregation, reduced epithelial infection, and enhanced IAV clearance by phagocytic cells. Previous studies showed that porcine SP-D (pSP-D) exhibits distinct antiviral activity against IAV as compared to human SP-D (hSP-D), mainly due to key residues in the lectin domain of pSP-D that contribute to its profound neutralizing activity. These observations provided the basis for the design of a full-length recombinant mutant form of hSP-D, designated as “improved SP-D” (iSP-D). Inspired by pSP-D, the lectin domain of iSP-D has 5 amino acids replaced (Asp324Asn, Asp330Asn, Val251Glu, Lys287Gln, Glu289Lys) and 3 amino acids inserted (326Gly-Ser-Ser). Characterization of iSP-D revealed no major differences in protein assembly and saccharide binding selectivity as compared to hSP-D. However, hemagglutination inhibition measurements showed that iSP-D expressed strongly enhanced activity compared to hSP-D against 31 different IAV strains tested, including (pandemic) IAVs that were resistant for neutralization by hSP-D. Furthermore, iSP-D showed increased viral aggregation and enhanced protection of MDCK cells against infection by IAV. Importantly, prophylactic or therapeutic application of iSP-D decreased weight loss and reduced viral lung titers in a murine model of IAV infection using a clinical isolate of H1N1pdm09 virus. These studies demonstrate the potential of iSP-D as a novel human-based antiviral inhalation drug that may provide immediate protection against or recovery from respiratory (pandemic) IAV infections in humans
World Association for the History of Veterinary Medicine 44th International Congress : 27-29 February 2020, The Farm Inn Hotel and Conference Centre, Pretoria, South Africa : proceedings
Until late in the 19th century, Utrecht University played a very important role in providing academic training for South African students. Professors at Utrecht stressed the Dutch roots of the Boers and supported their cause. The board of the veterinary faculty encouraged collaboration with colleagues from the veterinary school at Onderstepoort. Not only would this broaden the scientific horizon, but also create jobs for Dutch vets in South Africa, in addition to employment in the Dutch East Indies. Hence, the connection with Onderstepoort was framed in the context of colonial veterinary medicine. The collaboration became concrete. In 1931 Phillipus Fourie, deputy director of Veterinary Services at Onderstepoort, became the first foreigner to receive a PhD in veterinary medicine at Utrecht University. Otto Nieschulz from Utrecht was a guest lecturer at Onderstepoort in 1931 and 1933. Sir Arnold Theiler received an honorary doctorate from Utrecht University in 1936.
Theiler’s successor, Petrus du Toit, was awarded the title ‘Doctor honoris causa’ in Utrecht in 1948, the same year in which apartheid was officially adopted in South Africa. In the 1960s and 1970s ethical debates on the colonial heritage were held within Dutch politics. The post-colonial era witnessed a shift from colonial exploitation to development collaboration. While attention was mainly focused on new collaboration with Indonesia, the relation with South Africa became more and more uneasy. The dubious role Dutchmen had played in this former colony, ultimately resulting in apartheid, was heavily criticized. In addition to the international boycott after 1960, the Netherlands imposed a cultural and academic boycott against South Africa in 1986.
After the abolition of apartheid in 1990, rapprochement between Utrecht University and South African universities took place. This was part of a broader development collaboration between Utrecht University and universities in Zimbabwe and Mozambique. The new contact with the old partner led to chairs established in both cities. Frans Jongejan from Utrecht was appointed as extraordinary professor in tropical veterinary medicine at Onderstepoort, while Koos Coetzer from Pretoria became part-time professor in tropical animal health at the veterinary faulty in Utrecht in 2001. Since then, research projects are being carried out while postgraduate courses are taught with mutual participation.Presentation delivered at the 44th International Congress of the World Association for the History of Veterinary Medicine held from the 27-29 of February 2020 at The Farm Inn Hotel and Conference Centre, Pretoria, South AfricaConference sponsored by INDEXX, South African Veterinary Association, Ultra Dog, UNISA College of Agriculture and Environmental Science, Veterinary History Society of South Africa, Zoetis and SAVETCONab202
On the Breeds of Cattle—Historic and Current Classifications
Classification of cattle breeds contributes to our understanding of the history of cattle and is essential for an effective conservation of genetic diversity. Here we review the various classifications over the last two centuries and compare the most recent classifications with genetic data. The classifications devised during the 19th to the late 20th century were in line with the Linnaean taxonomy and emphasized cranial or horn morphology. Subsequent classifications were based on coat color, geographic origin or molecular markers. Several theories were developed that linked breed characteristics either to a supposed ancestral aurochs subspecies or to a presumed ethnic origin. Most of the older classifications have now been discarded, but have introduced several Latin terms that are still in use. The most consistent classification was proposed in 1995 by Felius and emphasizes the geographic origin of breeds. This is largely in agreement with the breed clusters indicated by a biochemical and molecular genetic analysis, which reflect either groups of breeds with a common geographic origin or single breeds that have expanded by export and/or crossbreeding. We propose that this information is also relevant for managing the genetic diversity of cattle
Changes in the Microstructure of a Comminuted Meat System During Heating
As part of a series of experiments on heating of a comminuted meat system , image analyses were conducted to quantify microstructural changes that could be visualized by light microscopy. Three different batches of comminuted meat were investigated. Two batches (A and B) were prepared without polyphosphate; one of these (B) was deliberately overchopped. One batch containing 0. I% polyphosphate was prepared (C). All batches were heated at I I different temperatures ranging from 40 to 115 °C. The microstructure of the three types of meat batte rs at the end of the com minu tion process differed. These types of meat batters al so revealed a diffe re nt pattern of fat and j elly release after the different temperatu re treatment s. This coinc ided with microstruc tural changes. The tatter included changes in the a real percentage , numerical density, shape factor , and size distribution of pores in the protein matrix measured in defatted histological sections. The highest mobility of fat and jelly was associated with the highest area percentage {A and C) and number of pores (A , Band C)
On the history of cattle genetic resources
Cattle are our most important livestock species because of their production and role in human culture. Many breeds that differ in appearance, performance and environmental adaptation are kept on all inhabited continents, but the historic origin of the diverse phenotypes is not always clear. We give an account of the history of cattle by integrating archaeological record and pictorial or written sources, scarce until 300 years ago, with the recent contributions of DNA analysis. We describe the domestication of their wild ancestor, migrations to eventually all inhabited continents, the developments during prehistory, the antiquity and the Middle Ages, the relatively recent breed formation, the industrial cattle husbandry in the Old and New World and the current efforts to preserve the cattle genetic resources. Surveying the available information, we propose three main and overlapping phases during the development of the present genetic diversity: (i) domestication and subsequent wild introgression; (ii) natural adaptation to a diverse agricultural habitat; and (iii) breed development
Participation of breast and leg muscles in shivering thermogenesis in young turkeys and guinea fowl
Turkey (Meleagris gallopavo) and guinea fowl (Numida meleagris) chicks (0-27 days posthatch) were exposed to decreasing or increasing ambient temperatures. Root mean square electromyographic activity of musculus pectoralis (m. pect.) and musculus iliotibialis (m. iliot.) was recorded simultaneously with O2 consumption and CO2 production. From both muscles, relative mass, water fraction and fibre type were determined. M. iliot. participated in shivering from hatching onwards. The relationship between its root mean square electromyographic activity and ambient temperature resembled that of metabolic rate and ambient temperature, and the shivering threshold temperature was indistinguishable from the lower critical temperature. This suggests that the leg muscles are major contributors to shivering thermogenesis. M. pect. participated in shivering only at days 6-20 in turkeys and at days 6-10 in guinea fowl. Both water fraction and histological analysis indicated that m. pect. was less developed than m. iliot. at hatching. We hypothesize that a minimal level of maturity is required before a muscle can participate in shivering, which is probably represented by a water fraction of about 0.85. Both species recruited the aerobic leg muscles first; the anaerobic breast muscle was recruited only when the rate of mass-specific heat loss was high