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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Proteólise miofibrilar e maciez da carne de bovinos (Bos indicus) submetidos a diferentes técnicas pós-morte de resfriamento das carcaças / Myofibril fragmentation index and shear force of Bos indicus steers and heifers submitted to different hanging positions during chilling

Eliane Bonifácio Silva 18 November 2005 (has links)
O objetivo deste trabalho foi avaliar a posição da suspensão de carcaças durante o período de resfriamento, no primeiro experimento lados alternados de dez animais Nelores machos castrados, foram suspensos pelo método tradicional (Tendão de Aquiles) ou dispostos horizontalmente em pallets, no segundo experimento lados alternados de 16 animais machos castrados e 16 fêmeas foram suspensos pelo método tradicional (Tendão de Aquiles) ou pelo músculo Carpo Radial. Amostras do músculo Longissimus dorsi na 12ª costela foram coletadas de todos os lados (42 lados esquerdos e 42 lados direitos) após o período de 24 horas de resfriamento, estas amostras foram embaladas a vácuo e maturadas por sete dias antes de serem congeladas e armazenadas até a realização das analises de força de cisalhamento, perdas de água por cocção e índice de fragmentação miofibrilar (MFI). Para a primeira experiência nenhuma diferença foi observada para espessura de gordura subcutânea, perdas de água por cocção, força de cisalhamento e MFI.Na segunda experiência não houve diferença para espessura de gordura entre os tratamentos, mas as fêmeas apresentavam maior espessura que os machos. Para perdas de água por cocção e força de cisalhamento não houve diferença, mas observando o MFI existe diferença entre os machos e fêmeas e também entre os métodos de pendura. A média de MFI para o tratamento de suspensão pelo Carpo Radial foi maior do que a suspensão pelo tendão de Aquiles. / The objective of this work was to evaluate the carcass hanging position during the chilling period in which 1st experiment: alternate sides of ten Nellore steers were hang either by the traditional way (Achilles tendon) or placed horizontally over pallets or 2nd experiment: alternate sides of 16 Nellore steers and 16 Nellore heifers were hang either by the Achilles tendon or by the Carpus radial muscle of the forequarter. Longissimus dorsi muscle samples at the 12th rib level were removed from all sides (42 left and 42 right sides) after a 24 hr chilling period, vacuum packaged and aged for 7 days before being frozen and kept for future analysis of shear force, cooking losses and Myofibril fragmentation index (MFI). For the first experiment no differences were observed for fat thickness, cooking losses, shear force and MFI. In the second experiment there was not differences for fat thickness between treatments but heifers showed a thicker fat layer than steers. For cooking losses and shear force there was not differences although for the MFI and hanging position between heifers and steers were observed. The MFI average of the treatment hang by the Carpus radial muscle were higher than the treatment hang by the Achilles tendon.
32

Estudo proteômico da carne de bovinos castrados da raça Nelore com genótipos contrastantes para CAPN e UOGCAST em diferentes períodos de maturação / Proteomic study of beef from castrated Nellore with contrasting genotypes for CAPN and UOGCAST at different stages of aging

Vanessa Augusto de Mello e Silva 15 October 2012 (has links)
O Brasil dedica-se em grande parte à criação de animais Bos indicus, principalmente da raça Nelore e seus cruzamentos, já que são animais resistentes a doenças e adaptados ao clima tropical. Entretanto, em relação à característica de maciez da carne, restrições têm sido atribuídas a este tipo de animal. Particularmente neste aspecto, existe grande interesse pela seleção de animais cuja genética seja favorável à carne mais macia e com redução na variação da maciez da carne. Durante o período de maturação da carne, a proteólise é o fator que mais contribui com o aumento da maciez. As proteases neutras ativadas por íons de cálcio, denominadas calpaínas, são parcialmente responsáveis pela proteólise post mortem, conduzindo ao aumento progressivo da maciez da carne. Entretanto, existe dificuldade em obter dados fenotípicos relacionados à maciez. Assim, a Seleção Assistida por Marcadores (MAS) pode ter grande impacto para melhorar estas características de difíc il mensuração. Marcadores do gene da calpaína (CAPN) e da calpastatina (CAST), denominados SNPs (Single Nucleotide Polymorphisms), já foram analisados e polimorfismos foram associados favoravelmente com maciez da carne bovina. Entretanto, pouco se conhece sobre a expressão gênica da calpaína e da calpastatina, particularmente em bovinos castrados da raça Nelore com diferentes combinações genotípicas para os marcadores moleculares SNP associados a essas proteases. Assim, este estudo teve como objetivo avaliar a expressão gênica da calpaína e da calpastatina em animais castrados da raça Nelore, com genótipos contrastantes identificados previamente por marcadores SNPs para um, sete e 14 dias de maturação. Foram genotipados 16 animais castrados da raça Nelore e dois marcadores foram utilizados, sendo um associado ao gene da µ-calpaína e outro associado à calpastatina (CAPN4751 e UOGCAST). Através da eletroforese bidimensional (2DE) as intensidades de expressão dos spots foram determinadas. As análises estatística s foram realizadas com auxílio do programa Statistical Analysis System (SAS), utilizando o procedimento PROC MIXED. A proteólise post mortem entre os tempos determinados de maturação foi avaliada e foram observados que 41 spots apresentaram efeitos significativos entre os tempos de maturação. Seis spots explicaram 57% da variabilidade da maciez aos 14 dias de maturação. Com o objetivo de verificar a existência de possíveis diferenças de expressão gênica entre amostras com genótipos distintos, avaliações proteômicas foram realizadas visando avaliar as diferenças no perfil proteico e foram baseadas no estudo comparativo (match) dos géis inter e intra combinações genotípicas. Dois spots explicaram 69% da variabilidade da maciez aos sete dias de maturação. Para o período de 14 dias de maturação 19 spots apresentaram efeito principal significativo para a fonte de variação de interação CAPN4751(UOGCAST) e, neste caso, a análise de regressão apresentou um spot que explica 70% da variabilidade da maciez aos 14 dias de maturação. / Brazil is largely devoted to the breeding of Bos indicus, especially Nellore and their intersections, because these animals are resist ant to diseases and adapted to tropical climate. However, in relation to beef tenderness, restrictions have been assigned to this breed. Particularly in this respect, there is great interest in the genetic selection of animals with more tender beef and reduced variation in meat tenderness. During the aging of the meat, proteolysis is the major factor that contributes to the increased tenderness. The neutral proteases activated by calcium ions, called calpains, are partially responsible for postmortem proteolysis, leading to a progressive increase in meat tenderness. However, there is difficulty in obtaining phenotypic data related to tenderness, in this way, Marker Assisted Selection (MAS) may have great impact to improve these characteristics. Gene markers of calpain (Capn) and calpastatin (CAST), called SNPs (single nucleotide polymorphisms) have been studied and polymorphisms were associated positively with beef tenderness. However, not much is known about the gene expression of calpain and calpastatin, particularly in Nellore steers with different genotype combinations for the SNP markers associated with these proteases. This study aimed to evaluate the gene expression of calpain and calpastatin in castrated Nellore, with contrasting genotypes previously identified by SNPs marker for one, seven and 14 days of aging. We genotyped 16 castrated Nellore, and two markers were used, one being associated with the µ-calpain gene and the other associated with calpastatin (CAPN4751 and UOGCAST). Through two-dimensional electrophoresis (2DE) the intensities of the spots were determined. Statistical analyzes were performed using the Statistical Analysis System (SAS) using the PROC MIXED. The postmortem proteolysis among the times of aging was evaluated and it was observed that 41 spots showed significant effects between different times of aging. Six spots explained up to 57% of the variability of tenderness at 14 days of aging. In order to verify the existence of possible differences in expression among samples with different genotypes, proteomics aimed to evaluate the differences in protein profile, based on comparative study (match) of the gels inter and intra genotype combinations. Two spots explained up to 69% of the variability of tenderness to seven days of maturation. For the period of 14 days of aging 19 spots showed significant main effect for interaction CAPN4751(UOGCAST), in this case regression analysis showed a spot that explains 70% of the variability of tenderness to 14 days of aging.
33

Efeitos da posição da carcaça durante o resfriamento na qualidade da carne bovina / Effects of the position of the carcass during the chilling period in the quality of beef

Denise Mücke 18 January 2006 (has links)
Dez novilhos Nelores, com média de 36 meses, foram abatidos no Abatedouro-Escola da Faculdade de Zootecnia e Engenharia de Alimentos da PCAPS-USP e lados alternados de suas carcaças foram resfriados pelo sistema tradicional, tendão de Aquiles do traseiro especial (TA), ou na forma horizontal (HO). As carcaças foram resfriadas por 48 horas, entre 0-2ºC. Foi avaliada a área de olho de lombo (AOL) e espessura de gordura subcutânea (EGS). Em seguida, foram retiradas amostras dos músculos Longissimus dorsi (LD), Quadríceps femoris (QF), Supraspinatus (SU), Psoas major (PM) e Semitendinosus (ST), embaladas a vácuo, maturadas por 5 dias em câmara de resfriamento e congeladas para posterior análises. Não houve diferença entre a EGS e a AOL para o LD dos tratamentos TA e HO. As amostras foram descongeladas em câmara fria vinte e quatro horas antes das análises e a seguir a maciez foi avaliada pelo método Warner Bratzler Shear Force. Não houve diferença na maciez dos músculos SU, PM e ST, independente do tratamento. Porém, a força de cisalhamento do QF (p=0,0291) foi menor para o HO (5,13 kg) do que para o TA (6,24 kg). O mesmo foi observado para o músculo LD (p=0,0068), com valores de força de cisalhamento de 6,38 kg para HO e 7,73 kg para TA. O LD e QF de carcaças mantidas na posição horizontal foram mais macios. Outras pesquisas que avaliem o índice de fragmentação miofibrilar e o comprimento do sarcômero devem ser realizadas. / Ten Nellore steer carcasses, with average age of 36 months were slaughtered at the meats lab of FZEA – USP and alternate right or left sides were placed in the cooler hung either by the Achilles tendon (TA) or horizontally placed over pallets, outside facing up (HO). Carcass were chilled for 48 hours at 0 – 2ºC. After the chilling period, loin eye area (LEA) and fat thickness (FT) were measured. One inch thick samples from each of the following muscles were removed, loin, tenderloin, eye round, knuckle and chuck tender and after 5 days in the cooler were frozen for future analysis. There was not a statistical difference for LEA and FT between treatments. After thawing the samples were analyzed for shear force through the Warner Bratzler device and there was not statistical difference for the tenderloin, eye round and chuck tender muscles between treatments. The shear force of the knuckle (5.13 Kg) was lower (p=0.029) for the HO treatment than for the TA (6,24 Kg). The loin also had a shear force of 6,4 Kg statistically lower (p=0.007) for the HO treatment when compared to 7.7 Kg for the TA treatment. The loin and knuckle of the carcasses cooled horizontally were more tender. Further studies evaluating MFI and sarcomere length must be done.
34

Efeitos da posição da carcaça durante o resfriamento na qualidade da carne bovina / Effects of the position of the carcass during the chilling period in the quality of beef

Mücke, Denise 18 January 2006 (has links)
Dez novilhos Nelores, com média de 36 meses, foram abatidos no Abatedouro-Escola da Faculdade de Zootecnia e Engenharia de Alimentos da PCAPS-USP e lados alternados de suas carcaças foram resfriados pelo sistema tradicional, tendão de Aquiles do traseiro especial (TA), ou na forma horizontal (HO). As carcaças foram resfriadas por 48 horas, entre 0-2ºC. Foi avaliada a área de olho de lombo (AOL) e espessura de gordura subcutânea (EGS). Em seguida, foram retiradas amostras dos músculos Longissimus dorsi (LD), Quadríceps femoris (QF), Supraspinatus (SU), Psoas major (PM) e Semitendinosus (ST), embaladas a vácuo, maturadas por 5 dias em câmara de resfriamento e congeladas para posterior análises. Não houve diferença entre a EGS e a AOL para o LD dos tratamentos TA e HO. As amostras foram descongeladas em câmara fria vinte e quatro horas antes das análises e a seguir a maciez foi avaliada pelo método Warner Bratzler Shear Force. Não houve diferença na maciez dos músculos SU, PM e ST, independente do tratamento. Porém, a força de cisalhamento do QF (p=0,0291) foi menor para o HO (5,13 kg) do que para o TA (6,24 kg). O mesmo foi observado para o músculo LD (p=0,0068), com valores de força de cisalhamento de 6,38 kg para HO e 7,73 kg para TA. O LD e QF de carcaças mantidas na posição horizontal foram mais macios. Outras pesquisas que avaliem o índice de fragmentação miofibrilar e o comprimento do sarcômero devem ser realizadas. / Ten Nellore steer carcasses, with average age of 36 months were slaughtered at the meats lab of FZEA – USP and alternate right or left sides were placed in the cooler hung either by the Achilles tendon (TA) or horizontally placed over pallets, outside facing up (HO). Carcass were chilled for 48 hours at 0 – 2ºC. After the chilling period, loin eye area (LEA) and fat thickness (FT) were measured. One inch thick samples from each of the following muscles were removed, loin, tenderloin, eye round, knuckle and chuck tender and after 5 days in the cooler were frozen for future analysis. There was not a statistical difference for LEA and FT between treatments. After thawing the samples were analyzed for shear force through the Warner Bratzler device and there was not statistical difference for the tenderloin, eye round and chuck tender muscles between treatments. The shear force of the knuckle (5.13 Kg) was lower (p=0.029) for the HO treatment than for the TA (6,24 Kg). The loin also had a shear force of 6,4 Kg statistically lower (p=0.007) for the HO treatment when compared to 7.7 Kg for the TA treatment. The loin and knuckle of the carcasses cooled horizontally were more tender. Further studies evaluating MFI and sarcomere length must be done.
35

Effects of Beef Finishing Diets and Muscle Type on Meat Quality, Fatty Acids and Volatile Compounds

Chail, Arkopriya 01 May 2015 (has links)
Consumer evaluation, proximate data, Warner-Bratzler shear force (WBSF), fatty acid (FA) composition and volatile compounds were analyzed from the Longissimus thoracis (LT), Tricep brachii (TB) and Gluteus medius (GM) muscles finished on conventional feedlot (FL) and forages, including a perennial legume, birdsfoot trefoil (BFT; Lotus corniculatus), and a grass, meadow brome (Bromus riparius Rehmann, Grass). Representative retail forage (USDA Certified Organic Grass-fed, COGF) and conventional beef (USDA Top Choice, TC) were investigated (n = 6) for LT. Additionally, the effects of diet on Gluteus medius (GM) and Tricep brachii (TB) muscles were explored. Forage-finished beef scored lower (P < 0.05) in most of the affected sensory attributes except BFT which was similar to grain-finished beef. In forage-finished beef GM was more liked and in FL, TB was similar to GM except juiciness where it scored greater. The fat percent was found to be greatest (P < 0.05) in TC followed by BFT and FL. Nutritionally beneficial ratios of FAs were observed in forage-finished diet. Fatty acid concentrations were majorly affected (P ≤ 0.046) by diet. Few long-chain PUFAs were affected (P ≤ 0.015) by muscle type. No FA was a effected (P > 0.05) by the interaction of muscle and diet. 3-hydroxy-2-butanone, known to evoke a buttery sensation was affected (P = 0.011) by diet with greater (P < 0.05) concentration in GM across all diets. Strecker degradation products were affected (P ≤ 0.014) by muscle type being prominent in GM. Meanwhile, 2-ethyl-3,5-dimethyl-pyrazine was greatest (P < 0.05) in BFT. All pyrazine compounds were (P < 0.05) greater in GM. These results indicate that when consumer evaluated beef of finishing diets, FL beef was rated highly. Additionally, not all forages produce similar beef. There were similar ratings for BFT for all attributes except flavor having lower values compared with FL. The chemical composition of BFT beef was found to be intermediary and similar to both FL and Grass beef in many cases. Diet was found to interact with muscle for sensory and chemical measures. The GM and TB of FL did not differ (P < 0.05), while within forage treatments sensory response and chemical composition varied. These results indicate the meat quality of secondary beef muscles is more greatly impacted by forage diets.
36

Mechanoelectrochemistry of electroactive polymers using shear-force based near-field microscopy

Venkatesh, Vijay 01 October 2020 (has links)
No description available.
37

Smart Prosthetic for Lower Limb Amputees Utilizing a Novel Shear and Normal Force Sensor

Lohrer, John January 2017 (has links)
No description available.
38

Fysisk belastning under patienthantering med fokus på ländrygg. / Physical load on healthcare worker’s lower back during patient handling.

Gray, Charlie, Bülow, Fredrik January 2024 (has links)
Bakgrund: Inhämtning av kunskap om och kvantifiering av belastning i ländryggen är en essentiell aspekt för att adressera den belastning och ländryggssmärta som finns bland vårdpersonal som utför fysiskt krävande arbete. Mätningen och utvärderingen av denna belastning utgör en betydande del av det preventiva arbetet för att identifiera riskfaktorer och främja en hälsosam arbetsmiljö.  Syfte: Denna översiktsstudie syftar till att granska den aktuella vetenskapliga litteraturen om kompressions- och skjuvkrafter som påverkar ländryggen hos vårdpersonal under patienthantering. Studien undersöker de vanligaste mätmetoderna för att mäta dessa krafter, den kompressions- och skjuvkraft ländryggen utsätts för hos vårdpersonal under patienthantering, efterlevnaden av riktlinjer för tunga lyft samt effekterna av olika interventioner på uppmätt ländryggsbelastning.  Metod: Denna översiktsstudie har genomförts i enlighet med Statens beredning för medicinsk och social utvärderings (SBU) metodbok. Bedömning av BIAS-risk utfördes med hjälp av SBU;s bedömningsmallar baserade på en modifierad version av QUADAS-2. Vetenskapliga artiklar samlades in via sökningar i PubMed-databasen.  Resultat: Totalt inkluderades 14 studier i denna studie. Dessa studier omfattade sammanlagt 337 deltagare. Alla inkluderade studier utvärderade både kompressionskrafter och skjuvkrafter som utfallsmått och använde reliabla samt validerade mätmetoder som mätinstrument. Resultaten tyder på att belastningen på vårdarnas ländryggar ofta överstiger de rekommenderade nivåerna för kompressions- och skjuvkrafter.  Slutsats: Studien ger signifikant bevisning för en potentiell positiv effekt av olika hjälpmedel på ländryggsbelastning, men det finns även motstridig forskning som pekar på motsatt resultat. Det finns tydliga indikationer på att använda rätt teknik under lyft och att bibehålla en ergonomisk kroppsställning kan bidra till att minska risken för belastningsrelaterade skador och främja hälsa och välbefinnande.
39

Component analysis of a fully implemented sectional WPC-beam with tribologic value as sliding rail utilized in a overhead conveyor system

Eichhorn, Sven, Schubert, Christine 02 October 2014 (has links) (PDF)
The sectional beam is the essential detail of an overhead conveyor. The construction element is stressed by time-varying mechanical and tribological loads. Here, we discuss the influence of the manufacturing process on the mechanical properties and the serviceability of the extruded profile in a selected application. The development of existing formulas and processing parameters are shown with the objective to expand the material application from WPC-decking to use in mechanical engineering. / Das Tragprofil ist das zentrale Element in einem Hängefördersystem. Das Bauteil wird durch zeitlich veränderliche mechanische und tribologische Lasten beansprucht. Nachfolgend wird der Einfluss des Herstellungsprozesses auf die mechanischen Eigenschaften und die Gebrauchsfähigkeit eines extrudierten Trag- und Gleitprofils aus WPC im gewählten Anwendungsfall vorgestellt. Die notwendige Weiterentwicklung bestehender Rezepturen und Verarbeitungsverfahren wird aufgezeigt, um den Anwendungsbereich des Werkstoffes WPC vom Bereich Terassendielen auf den Maschinenbau zu erweitern.
40

Effects of supplementing feedlot steers and heifers with Zilpaterol hydrochloride on Warner-Bratzler Shear Force of steer longissimus lumborum and heifer longissimus lumborum, triceps brachii and gluteus medius muscles aged for 7, 14 and 21 days

Claus, Heidi L. January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Michael E. Dikeman / The longissimus lumborum (LL) muscle from 117 steers and the LL, gluteus medius (GM), and triceps brachii (TB) from 132 heifers were obtained to evaluate the effects of feeding zilpaterol hydrochloride (Zilmax®; ZH) (7.56g/907kg on a 100% DM basis) on tenderness. Both genders were blocked by initial weight into 6 blocks of 4 pens. Pens were assigned to treatments of either 0, 20, 30 or 40 d on ZH, with a 3 d withdrawal. One steak was removed from each muscle for proximate analysis and three 2.54 cm thick steaks were vacuum aged for either 7, 14 or 21 d. Steaks were cooked to 70 ˚C and six 1.27 cm diameter cores were removed for Warner-Bratzler shear force (WBSF) determinations. All muscles from steers and heifers fed 30 and 40 d with ZH, had higher (P < 0.05) WBSF compared with controls. The WBSF of steer LL and heifer TB from the 20 d treatment was higher (P < 0.05) than controls. There were no treatment by aging interactions (P > 0.05) for WBSF of steaks from steer LL, heifer LL or heifer TB, but there was a treatment by aging interaction (P < 0.05) for WBSF of steaks from heifer GM. There were no differences (P > 0.05) in percent intramuscular fat for any muscle due to treatment. When using percent intramuscular fat as a covariate, differences in WBSF of steer LL and heifer TB were not altered, but there were slight differences in heifer LL and GM WBSF due to treatment when compared with not using percent fat as a covariate. Percentages of steaks with WBSF ≥ 5 kg increased as days on ZH increased and decreased as days of aging increased. Warner-Bratzler shear force values among the three aging times for steer LL control, 20 and 40 d treatments; all heifer LL treatments, and heifer TB 20 d were all positively correlated (P < 0.01) with each other. Feeding ZH for 20 d generally increased WBSF values, but means were still acceptable. Feeding ZH for 40 d was very detrimental to tenderness.

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