Tesis sobre el tema "Absorptiometer"
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Durkin, Jennifer Dowling James. "Development of a geometric modelling approach for human body segment inertial parameter estimation /". *McMaster only, 2003.
Buscar texto completoKhoo, Benjamin Cheng Choon. "Clinical and phantom-based studies of the validity and value of quantitative radiological hip structural analysis". University of Western Australia. School of Surgery and Pathology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0189.
Texto completoAlkhalifah, K. "Applications of dual energy X-ray absorptiometry". Thesis, Swansea University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635758.
Texto completoLandström, Eric. "Material Identification using Multiple X-Ray Absorptiometry". Thesis, KTH, Numerisk analys, NA, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168573.
Texto completoDXA (Dual Energy X-ray Absorptiometry) är en teknik för att identifiera okända material genom att mäta transmissionen för två olika röntgenenergier. Den här metoden är begränsad till att mäta en kemiskt variation. Vid mer än en varierande komponent, kan MXA (Multiple Energy X-ray Absorptiometry) användas för att utröna mer information. MXA är dock begränsat av de små skillnaderna i de fysikaliska processerna som styr röntgenfotonernas interaktion med materialet. Teoretiskt är det bara möjligt att mäta tre egenskaper med MXA, varav en är beroende på provets geometri och densitet. De kvarvarande kemiska egenskaper är utforskade i den här rapporten. Det är möjligt att mäta en kemisk material egenskap med hög precision med röntgen energier mellan 20 - 90 keV. Två kemiska egenskaper går att mäta i vissa fall, dock är precisionen sämre och mätningen är känslig för fel i modelleringen av maskinen och mätningens stabilitet. I den tvåstegs metod som används uppskattas först de använda röntgenspectra och sedan återskapas provets attenueringskoefficient med en hög precision (< 0.2 %) med en lågranks bas av attenueringsegenskaperna.
Steel, Susan A. "Standards in clinical dual energy X-ray absorptiometry". Thesis, University of South Wales, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521629.
Texto completoRoussel, Nicolas. "Denoising of Dual Energy X-ray Absorptiometry Images and Vertebra Segmentation". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233845.
Texto completoDual Energy X-ray Absorptiometry (DXA) är en medicinsk bildbehandlingmodalitetsom används för att kvantifiera bentäthet och upptäckafrakturer. Det används i stor utsträckning tack vare sin låga kostnadoch sin låga exponering, men producerar brusiga bilder som kanvara svåra att förstå för en mänsklig expert eller en maskin. I den här studien undersöker vi avbrusning i DXA i laterala ryggradsbilderoch automatisk segmentering av ryggkotorna i de resulterandebilderna. För avbrusning skapar vi adaptiva filter för att förhindrafrekventa kantartefakter (korskontaminering), och validerar våraresultat med ett observatörsexperiment. Segmentering utförs medanvändning av djupa konvolutionella neuronnät tränade på manuelltsegmenterade DXA-bilder. Med få träningsbilder fokuserar vi pånätverksdjup och mängden träningsdata. På bästa djup rapporterarvi 94% medel-Dice på testbilder utan efterbehandling. Vi undersökerockså tillämpning av ett nätverk tränat på en av våra databaser till enannan databas (annan upplösning). Vi visar att i vissa fall kan korskontamineringförsämra segmenteringsresultatet och att användningenav våra adaptiva filter hjälper till att lösa problemet. Våra resultatvisar att även med få data och korta träningar så producerar neuuronnätkor- rekta segmenteringar. Detta tyder på att de kunde användasför frak- turklassificering. Dock, resultaten bör valideras på större databasermed fler fall av frakturer och andra patologier.
Almqvist, Heléne. "Studies on root hard-tissue demineralization and remineralization measured by ¹²⁵I absorptiometry". Stockholm : Karolinska Institutet, 1993. http://catalog.hathitrust.org/api/volumes/oclc/29572338.html.
Texto completoGulam, Misbah. "Phalangeal bone mineral density measurements using x-ray absorptiometry and computed tomography". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/MQ58041.pdf.
Texto completoSkipper, Julie A. "Feasibility of Radiographic Absorptiometry of the Mandible as an Osteoporosis Screening Method". Wright State University / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=wright1057695994.
Texto completoSalamat, Mohammad Reza. "Development of dual energy X-ray absorptiometry techniques for bone mineral measurement". Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/22614.
Texto completoIto, Kouta. "Use of the osteoporosis self-assessment tool : for referring older men for bone densitometry, a decision analysis /". Access full-text from WCMC :, 2008. http://proquest.umi.com/pqdweb?did=1527840081&sid=13&Fmt=2&clientId=8424&RQT=309&VName=PQD.
Texto completoStewart, Arthur D. "Body composition of athletes assessed by dual X-ray absorptiometry and other methods". Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/22658.
Texto completoAbdalla, Karim Yousif [Verfasser]. "Vergleich von Quantitativer Computertomographie und Dual-Energy XRay Absorptiometry bei postmenopausalen Frauen / Karim Yousif Abdalla". Ulm : Universität Ulm. Medizinische Fakultät, 2014. http://d-nb.info/1053705689/34.
Texto completoWallace, Joanne. "The impact of exercise on human body composition determined using dual energy X-ray absorptiometry". Thesis, Liverpool John Moores University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436552.
Texto completoTsaousis, Nikolaos. "Cortical thickness estimation of the proximal femur from multi-view, dual-energy X-ray absorptiometry". Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/252878.
Texto completoSutton, Laura Jane. "Total and regional body composition analysis in distinct populations determined by dual-energy X-ray absorptiometry". Thesis, Liverpool John Moores University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502755.
Texto completoGray, Rhonda Michelle. "The effects of varying hydration conditions on air displacement plethysmography and dual energy x-ray absorptiometry". Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1259761.
Texto completoSchool of Physical Education
Borgard, Christopher Patrick. "Assessing Body Composition Among Male Collegiate Runners and Swimmers Using Dual-Energy X-ray Absorptiometry (DXA)". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/250.
Texto completoCohen, Brian. "The assessment of peri-prosthetic bone remodelling in total hip arthroplasty using dual-energy X-ray absorptiometry". Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266102.
Texto completoNowak, Kathryn M. "A comparison of body fat percentage estimates between duel-energy X-ray absorptiometry and air displacement plethysmography". Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1315175.
Texto completoSchool of Physical Education, Sport, and Exercise Science
Kelsey, Laurel Anne. "Variance In Percent Body Fat Between And Within Families As Measured By Dual-energy X-ray Absorptiometry". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd536.pdf.
Texto completoSmith, Jarvis J. "Lower limb skeletal muscle mass in children with cerebral palsy estimation with dual-energy X-ray absorptiometry /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 64 p, 2009. http://proquest.umi.com/pqdweb?did=1674094551&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completoJunge, Janine. "Chemische Zusammensetzung und Knochendichtemessung mit der Dualenergie-Röntgenabsorptiometrie (DEXA, Dual Energy X-Ray Absorptiometry) der Röhrbeine beim Pferd". Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-99344.
Texto completoDXA (dual energy X-ray absorptiometry) is an established method for the measurement of bone mineral density (BMD), bone mineral content (BMC) and whole body composition in human and partly in veterinary medicine. However, there are only a small number of studies that examine the bone in horses using DXA. All these studies are based on small samples. Therefore, the objective of this study was to validate the use of DXA for the measurement of BMD and BMC in the horse. In total the cannons of 103 horses were scanned ex vivo, using the PIXI LUNAR® densitometer. In human medicine this densitometer is used for the exami-nation of the forearm. The measuring point was the exact middle between basis and caput of the third metacarpal/metatarsal bone. In a second step the DXA measurements were complemented with a chemical analysis, analyzing the ash content, calcium, phosphorus and magnesium content of the bones. The results are presented as median and 25-/75-percentile. The average ash content of the cannon bones was 698 (691 - 703) g/kg DM. The average mineral content was measured in the following order: calcium 265 (259 - 272) g/kg DM, phosphorus 123 (121 - 126) g/kg DM und magnesium 2.44 (2.19 - 2.66) g/kg DM. The ratio of calcium to phosphorus ranged from 2.14 to 2.18. The DXA results are influenced not only by the bone´s mineral content, but also by its diameter. Because of this the results are separated into the results of the forelimb (fl) and the hindlimb (hl) which generates the following results: BMD: fl 3.22 (2.80 - 3.65) g/cm², hl 4.21 (3.76 - 4.65) g/cm²; BMC: fl 26.5 (22.8 - 30.1) g, hl 32.9 (29.0 - 36.3) g. Several robustness checks of the measurements were conducted. For the BMD measurements, the range of measurements diverged by 3.51-4.48 % for measurements with limb repositioning, and by 1.06-1.85 % for measurements without limb repositioning. For the BMC measurements, the range of measurements diverged by 3.38-3.94 % for measurements with limb repositioning, and by 1.28-2.79 for measurements without limb repositioning. To determine the importance of the exact bone position for follow-up investigations, measurements in a distance of one, two and three centimeters proximal and distal of the original measuring point were performed. The results of these measurements deviated from the result of the central measuring point at the centre of the diaphysis in a range of 3.53 – 9.16 % for BMD and a range of 4.21 – 12.5 % for BMC. This variation falls within the percentiles of the central measuring point. Overall, the results of this study indicate that DXA is useable for determining BMD and BMC at the third metacarpal/metatarsal bone of the horse. The high reproducibility of the results and the distance measurements suggest that DXA is suitable for measurements at the standing, tranquilized horse. However, the cannon bone is a bone with a high content of cortical bone. This means that the diameter of the bone changes as a result of training or immobilization, while the BMD and BMC remain unchanged by such influence. This leads to a weak correlation between the results from the DXA and chemical analyses. Thus, while these two types of analysis fit well into the context of prior studies, a direct comparison between these measurements is not possible
Wood, Sarah Ellen. "The effectiveness of dual energy x-ray absorptiometry to non-invasively determine body composition of hybrid striped bass". College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1476.
Texto completoThesis research directed by: Dept. of Animal and Avian Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Elmasri, Karima. "A robust technique for the detection and quantification of abdominal aortic calcification using dual energy X-ray absorptiometry". Thesis, Cardiff University, 2018. http://orca.cf.ac.uk/115458/.
Texto completoDendere, Ronald. "Hand X-ray absorptiometry for measurement of bone mineral density on a slot-scanning X-ray imaging system". Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13342.
Texto completoBone mineral density (BMD) is an indicator of bone strength. While femoral and spinal BMDs are traditionally used in the management of osteoporosis, BMD at peripheral sites such as the hand has been shown to be useful in evaluating fracture risk for axial sites. These peripheral locations have been suggested as alternatives to the traditional sites for BMD measurement. Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring BMD due to low radiation dose, high accuracy and proven ability to evaluate fracture risk. Computed digital absorptiometry (CDA) has also been shown to be very effective at measuring the bone mass in hand bones using an aluminium step wedge as a calibration reference. In this project, the aim was to develop algorithm s for accurate measurement of BMD in hand bones on a slot - scanning digital radiography system. The project assess e d the feasibility of measuring bone mineral mass in hand bones using CDA on the current system. Images for CDA - based measurement were acquired using the default settings on the system for a medium sized patient. A method for automatic processing of the hand images to detect the aluminium step wedge, included in the scan for calibration, was developed and the calibration accuracy of the step wedge was evaluated. The CDA method was used for computation of bone mass with units of equivalent aluminium thickness (mmA1). The precision of the method was determined by taking three measurements in each of 1 6 volunteering subjects and computing the root - mean - square coefficient of variation (CV) of the measurements. The utility of the method was assessed by taking measurements of excised bones and assessing the correlation between the measured bone mass and ash weight obtained by incinerating the bones. The project also assessed the feasibility of implementing a DXA technique using two detectors in a slot-scanning digital radiography system to acquire dual-energy X-ray images for measuring areal and volumetric BMD of the middle phalanx of the middle finger. The dual-energy images were captured in two consecutive scans. The first scan captured the low- energy image using the detector in its normal set-up. The second scan captured the high- energy image with the detector modified to include an additional scintillator to simulate the presence of a second detector that would capture the low-energy image in a two-detector system. Scan parameters for acquisition of the dual-energy images were chosen to optimise spectral separation, entrance dose and image quality. Simulations were carried out to evaluate the spectral separation of the low- and high-energy spectra.
Rea, Jacqueline Ann. "DXA vertebral morphometry studies in osteoporotic and healthy postmenopausal women". Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369292.
Texto completoWhitmarsh, Tristan. "3D reconstruction of the proximal femur and lumbar vertebrae from dual-energy x-ray absorptiometry for osteoporotic risk assessment". Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/94492.
Texto completoEn esta tesis se desarrolló un método para reconstruir tanto la forma 3D de estructuras óseas como la distribución de la DMO a partir de una sola imagen de DXA. El método incorpora un modelo estadístico construido a partir de una gran base de datos de QCT junto con una técnica de registro 3D-2D basada en intensidades. Se ha evaluado la capacidad del método para reconstruir la parte proximal del fémur a partir de una imagen DXA. Los parámetros resultantes de las reconstrucciones fueron evaluados posteriormente por su capacidad en discriminar una fractura de cadera. Por fin, se extendió el método a la reconstrucción de las vértebras lumbares a partir de DXA anteroposterior y lateral incorporando así un enfoque multi-objeto y multi-vista. Estos técnicas pueden potencialmente mejorar la precisión en la estimación del riesgo de fractura respecto a la estimación que ofrece la práctica clínica actual.
Weyers, Anna M. "Comparison of body composition using the Bod Pod and dual-energy x-ray absorptiometry before and after weight loss". Virtual Press, 2000. http://liblink.bsu.edu/uhtbin/catkey/1164840.
Texto completoSchool of Physical Education
Serra, Giulio. "Characterization of a dual-energy X-ray absorptiometry system for soft tissues assessment and their correlations with metabolic state". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8922/.
Texto completoDeodhar, Atulya A. "Development of dual energy X-ray absorptiometry to measure hand bone mineral content for the assessment of rheumatoid arthritis". Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362240.
Texto completoWarnock, Sarah M. "Cortical Bone Mechanics Technology (CBMT) and Dual X-Ray Absorptiometry (DXA) Sensitivity to Bone Collagen Degradation in Human Ulna Bone". Ohio University Honors Tutorial College / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1556305540256918.
Texto completoMaria, de Carvalho Albuquerque Melo Ana. "Estudo comparativo da antropometria e do DXA: uma nova equação de predição para avaliação da gordura centralizada em homens adultos jovens". Universidade Federal de Pernambuco, 2006. https://repositorio.ufpe.br/handle/123456789/8835.
Texto completoA obesidade é uma excessiva acumulação de energia sob a forma de gordura corporal com prejuízos à saúde. O aumento da prevalência de obesidade em diferentes populações leva a acreditar que esta condição clínica caminha para ser a mais importante causa de doença crônica no mundo. O objetivo deste trabalho foi o de avaliar a importância da obesidade em especial a central e seus fatores de risco à saúde em homens adultos jovens por meio de revisão da literatura, bem como, realizar um estudo comparativo entre duas técnicas de avalição da composição corporal: a Antropometria e o Dual Energy X-ray absorptiometry (DXA). O delineamento do estudo foi do tipo transversal com seleção aleatória. Participaram 45 indivíduos com idades entre 20 e 30 anos, distribuídos em três grupos segundo o Índice de Massa Corporal (IMC), nas categorias peso normal, pré-obeso e obeso I. O referido estudo originou uma nova equação de predição para a gordura centralizada utilizando o perímetro abdominal (Pab) e a gordura do tronco medida pelo DXA em homens adultos jovens, permitindo ainda classificar os referidos indivíduos em risco à saúde de acordo com o Z-score usando a quantidade de gordura estimada pela referida equação
Thomi, Franziska. "Impact of hydration status on body composition as measured by dual X-ray absorptiometry (DXA) in normal volunteers and patients on hemodialysis /". Bern, 1992. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Texto completoNewsome, Shaun. "Body Mass Index as a Parameter to Evaluate the Prevalence of Hypertension in NH White, NH Black, and Hispanic Americans". Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/iph_theses/226.
Texto completoGonçalves, Ezequiel Moreira 1977. "Avaliação da composição corporal em pacientes com a forma clássica da hiperplasia adrenal congênital por deficiência da enzima 21-hidroxilase". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/313826.
Texto completoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-19T19:08:43Z (GMT). No. of bitstreams: 1 Goncalves_EzequielMoreira_D.pdf: 5365817 bytes, checksum: 7f7c98bf013498181e9a1d0f32614cfc (MD5) Previous issue date: 2012
Resumo: Objetivos: a) Validar equações com base nas espessuras de dobras cutâneas (EDC) para estimar o percentual de massa gorda (%MG) e na impedância bioelétrica (BIA) para a massa isenta de gordura (MIG) em pacientes com hiperplasia adrenal congênita por deficiência da enzima 21-hidroxilase (HAC-D21OH); b) desenvolver equações específicas para estes pacientes para estimar o %MG e MIG, utilizando os valores determinados pela absorciometria por dupla emissão de raio X (DXA) como referência; e c) avaliar a relação entre os parâmetros da massa óssea (MO) determinados pela ultrassonometria quantitativa (QUS) das falanges proximais e sua capacidade de diagnosticar a baixa MO para a idade cronológica em comparação ao DXA em pacientes com HAC-D21OH. Casuística: Foram avaliados 71 pacientes de ambos os sexos, com idades entre seis e 27 anos. Métodos: Foram realizadas medidas antropométricas, de BIA, de DXA e de QUS em um mesmo dia. Foram testadas quatro equações (Eq. 1, 2, 3 e 4), previamente publicadas para a estimativa do %MG e quatro equações (Eq. 5, 6, 7, e 8) para a estimativa da MIG em kg, todas específicas para o sexo e faixa etária. Foram utilizados o teste t de Student, os parâmetros da regressão linear simples e a concordância entre os métodos para testar a validade das equações, regressão linear múltipla para desenvolver os novos modelos e a análise dos parâmetros da curva ROC para avaliar a capacidade diagnóstica do QUS. Resultados: Eq. 1, 2, 3, e 4, apresentaram alta correlação (R>0,80), porém subestimaram significativamente (p<0,01) os valores de %MG em comparação ao DXA. Com relação à MIG, apesar de todas as equações apresentarem R> 0,95, no geral apenas uma apresentou validade considerada aceitável (Eq. 6, grupo masculino). Foram desenvolvidas e validadas quatro equações propostas no presente estudo específicas para a estimativa do %MG e uma para a estimativa da MIG em pacientes HAC-D21OH. Os parâmetros do QUS apresentaram valores variando entre: 0,57-0,74 (R), 62,5-100% (sensibilidade) e 21-64,4% (especificidade) em relação ao DXA. Conclusão: As equações específicas para indivíduos com HAC-D21OH demonstraram maior validade para estimar a MIG e principalmente o %MG, comparadas as equações previamente publicadas e desenvolvidas a partir de amostras com pessoas saudáveis. O QUS apresentou relação significativa, porém moderada e baixa capacidade de diagnosticar a baixa MO para a idade cronológica quando comparado ao DXA nestes pacientes
Abstract: Objectives: a) To evaluate the accuracy of skinfold-based models, to estimate the percentage of fat mass (%FM) and the bioelectrical impedance analysis (BIA) to estimate fat-free mass (FFM) in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH-21OHD); b) to develop specific equations for these patients to estimate the % MG and MIG using dual-energy X-ray absorptiometry (DXA) as the reference method; and c) to evaluate the relationship between the parameters of bone mass (BM) determined by quantitative ultrasound of proximal phalanges (QUS) and the ability to diagnose low bone mass for chronological age in comparison to DXA in patients with CAH-21OHD. Patients: Seventy one patients of both genders, with age ranged from six and 27 years were inclued. Methods: Anthropometric measurements, BIA, DXA and to QUS were evaluated in the same day. Four equations (Eq. 1, 2, 3 and 4) previously published to estimate the %FM, and four equations (Eq. 5, 6, 7, and 8) to estimated the FFM, all specific for sex and age, the Student t test, the parameters of simple linear regression and the agreement between methods were used to test the validity of the equations, multiple linear regression to develop the new model and the parameters of the ROC curve to evaluate the diagnostic ability of QUS. Results: The four equations (Eq. 1, 2, 3, and 4) were highly correlated (R>0.80), but the %FM values were significantly underestimated (p<0.01) when compared to DXA. With respect to MIG, despite all the equations presented R>0.95, only one had acceptable validity (Eq. 6 for males). Four new specific equations to estimated %FM and one FFM were developed and validate in patients with CAH-21OHD. QUS parameters showed values ranging from 0.57 to 0.74 (R), 62.5 to 100% (sensitivity) and 21 to 64.4% (specificity) compared to DXA. Conclusion: The new specific equations for patients with CAH-21OHD showed greater validity to estimate FFM and mainly the %FM compared to previously equations published and developed with samples from healthy pearsons. The QUS showed a significant relationship, but moderate and low ability to diagnose low bone mass for chronological age when compared to DXA in these patients
Doutorado
Saude da Criança e do Adolescente
Doutor em Saude da Criança e do Adolescente
Liparulo, Timothy L. "The effects of varying hydration conditions on the estimation of body composition by bioelectrical impedance analysis, near infrared interactance, and dual-energy x-ray absorptiometry". Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1217378.
Texto completoSchool of Physical Education
Weigand, Anna Christine [Verfasser] y Armin [Akademischer Betreuer] Scholz. "Phenotyping of the visceral adipose tissue using Dual Energy X-ray Absorptiometry (DXA) and Magnetic Resonance Imaging (MRI) in pigs / Anna Christine Weigand ; Betreuer: Armin Scholz". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1230754849/34.
Texto completoPompeo, Jaqueline. "Avaliação da composição corporal através Dual-energy X-ray absorptiometry (DEXA) em recém-nascidos de muito baixo peso: efeito do uso de fortificante do leite materno". Pontifícia Universidade Católica do Rio Grande do Sul, 2011. http://hdl.handle.net/10923/4679.
Texto completoBACKGROUND: Dual-energy X-ray absorptiometry (DEXA) is considered the most accurate method for assessing body composition. With the steady increase in survival in premature babies there is an increasing interest in relation to nutritional assessment, since an adequate diet in the first weeks of life influences long-term development. Therefore the assessment of body composition is of fundamental importance in the nutritional care of preterm infantsOBJECTIVE: To evaluate body composition by dual-energy X-ray absorptiometry in preterm infants fed human milk supplemented (FM85 ®. Nestle Nutrition) or human milk. METHODS: We studied 26 newborn preterm infants less than 1500g birth weight, while in the conventional UTINeonatal Hospital São Lucas da PUCRS, between July 2006 and January 2010. The newborns were randomized into two groups: one group received human milk plus FM85 ® and Group 2 received human milk without FM85 ®. Anthropometric variables were recorded measures. Body composition was assessed by dual-energy X-ray absorptiometry. RESULTS: We compared 15 premature infants who used human milk FM85 ® and 11 who ate only human milk. The two groups showed no significant differences in the entrance and at the end of the study in relation to gestational age (mean 30. 2 ± 2. 38 without versus 30 ± 1. 62 without, P = 0. 76), weight (1232. 7 g versus 1161. 4 ± 166. 82 g ± 228. 43, p = 0. 37), length (37. 4 cm ± 1. 9 cm versus 36. 6 ± 2. 65, p = 0. 25) and perimeter circumference (26. 5 cm ± 2. 91 cm versus 25. 9 ± 1. 51, p = 0. 5). The percentages at the beginning and end of the study showed no significant difference in lean body mass (80 ± 1. 89 versus 80. 3 ± 1. 22, p = 0. 63), fat mass (19. 6 ± 1. 81 versus 19, 4 ± 1. 2, p = 0. 72) and bone mineral content (0. 4 ± 0. 3 versus 0. 18 ± 0. 09, p = 0. 18), The volume and percentage of ingested human milk as well as thelength of hospital stay was similar in both groups at the Neonatal care Unit discharge. The bone mineral content / kg was significantly higher in newborns receiving human milk plus FM85™ (5,46 ± 2,63 g/Kg versus 3,55 ± 1,54 g/Kg; p =0,04)CONCLUSIONS: There was no difference between groups in relation to lean body mass, fat mass and bone mineral content.
INTRODUÇÃO: A Dual-energy X-ray absorptiometry (DEXA) é considerada o método mais acurado para avaliação da composição corporal. Com o aumento progressivo da sobrevida em prematuros tem ocorrido um interesse crescente em relação a avaliação nutricional, uma vez que uma alimentação adequada nas primeiras semanas de vida influencia o desenvolvimento a longo prazo. Portanto a avaliação da composição corporal é de fundamental importância nos cuidados nutricionais dos prematuros. OBJETIVO: Avaliar a composição corporal através da Dual-energy X-ray absorptiometry em recém-nascidos prematuros alimentados com leite humano suplementado (FM85®. Nestlé Nutrition) ou leite humano.MÉTODOS: Foram estudados 26 recém-nascidos prematuros com menos de 1500g de peso ao nascimento, durante a internação na UTI Neonatal do Hospital São Lucas da PUCRS, entre julho de 2006 e janeiro de 2010. Os recém-nascidos foram randomizados em dois grupos: o grupo 1 recebeu leite humano acrescido de FM85® e o grupo 2 que recebeu leite humano sem FM85®. Foram registrados as medidas antopométricas. A composição corporal foi avaliada através da Dual-energy X-ray absorptiometry. RESULTADOS: Foram comparados 15 recém-nascidos prematuros que utilizaram leite humano com FM85® e 11 que ingeriram apenas leite humano. Os dois grupos não apresentaram diferenças significativas tanto na entrada como no final do estudo em relação a idade gestacional (média 30,2 sem ± 2,38 versus 30 sem ± 1,62; p = 0,76), peso (1232,7 g ± 166,82 versus 1161,4 g ± 228,43; p = 0,37), comprimento (37,4 cm ± 1,9 versus 36,6 cm ± 2,65; p = 0,25) e perímetro cefálico (26,5 cm ± 2,91 versus 25,9 cm ± 1,51; p = 0,5). As percentagens no início e ao final do estudo não apresentaram diferença significativa de massa magra (80 ± 1,89 versus 80,3 ± 1,22; p = 0,63), massa gorda (19,6 ± 1,81 versus 19,4 ± 1,2; p = 0,72) e conteúdo mineral ósseo (0,4 ± 0,18 versus 0,3 ± 0,09; p = 0,18), O volume percentual de leite humano ingerido, e tempo de internação também foram semelhantes entre os dois grupos no momento da alta. A concentração mineral óssea/Kg do grupo FM85® foi maior no grupo do leite humano suplementado (5,46 ± 2,63 g/Kg versus 3,55 ± 1,54 g/Kg; p =0,04) ao final do estudo. CONCLUSÕES: Não houve diferença entre os grupos em relação a massa magra, massa gorda e massa mineral óssea.
Jana, Ilić. "Povezanost između različitih faktora rizika za pojavu osteoporoze i koštane mase u postmenopauznih žena". Phd thesis, Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=101174&source=NDLTD&language=en.
Texto completoIntroduction: Osteoporosis is a systematic disease of skeleton characterized by the reduction of bone mass and changes in bone structure which result in the increased aptitude of bone tissue to fractures. According to the suggestion of the World Health Organization, the diagnosis for osteoporosis is set if the T-score is -2.5 SD and below it and the normal report if the value of T-score is -1.0 SD and above it. Nowadays, it is considered that the golden standard in osteoporosis diagnostic is the use of double X absorption densitometry of lumbal spine and hipe which provides the values of bone mass Bone mineral density as well as T-score. However, it has been known that there are risk factors whish influence the reduction of bone mass by reducing maximum bone mass gained by the age of 35 and/or by quckening, the normal process of gradual and mild reduction of bone mass starting after 35 and in that way increase the risk toward fractures. It mas also been known that some of the risk factors and their correlation may cause the increasement of the risk factor toward fractures not having the connection with the bone mass and T-score. Researchment aims: 1. Determine bone mass in postmenopausal women using double X absorption densitometry. 2. Analyse distribution of risk factors in patients whith the T-score below -2.5 SD comparing to the patients with T-score above -1.0SD. 3. Determine the relation between statistical space made by individual and associated risk factors (with the characteristics of each of them) and the bone mass specified by densitometry. Material and methods of working: Researchment is outlined partly as prospective and partly as retrospective study which was carried out in patients in postmenopausal life period, aged 50-80. After applying double X absorption densitometry of lumbal spine and hip the examined patients did the questionnaire by themselves whith the help of nurses and doctors. After obtaining the data, patients were divided into two groups: with and without osteoporosis. There were 270 patients in the group with osteoporosis and 250 of them without it. Thereafter, the statistic data processing was carried out. After the overall analysis of obtained results of researchment, following conclusions were conducted: 1. It has been determined that 60 % of postmenopausal women of average age 67.0±7.0 have osteoporosis, in other words, their T-score is ≤ -2.5 SD. 2. There is statistically important relationship between the bone mass and following risk factors: positive family anamnesis to osteoporosis and fractures, body weight, height, previos fractures, frequent falls and reduction of height for more than 3 cm. 3. Analysing the risk factors, characteristics of persons with osteoporosis have been obtained: positive family anamnesis to osteoporosis and fractures, smaller body weight and height, the reduction in height for more than 3 cm, frequent falls and previous fractures. 4. Hyperthyroidism and hyperparathyroidism, rheumatoid arthritis and the usage of corticosteroid therapy are the risk factors more incident in the examined patients with osteoporosis. 5. Smoking, early menopause, allergy to milk with no adequate substitution of calcium and insufficient exposition to sun rays with no adequate substitution of vitamine D are the risk factors more incident in patients with osteoporosis. 6. The largest contribution to the total makes positive family anamnesis to osteoporosis and fractures (20.99%), followed by body weight, height, Body mass index (19.03%), previos fractures, frequent falls and reduction in height for more than 3 cm (18.41%), smoking and insufficient physical activity (12.75%), allergy to milk and insufficient exposition to the sun (12.14%), early menopause (8.72%), hyperthyroidism and hyperparathyroidism, rheumatoid arthritis (7.93%). 7. By the analysis of all three goups of features giving the largest cintribution to the total, it has been determined that positive family anamnesis to fractures (37.7%), and body weight (31.3%), present the major risk factors for osteoporosis. 8. By mathematical processing we obtain the formula which can with the probability of 64.0% predict osteoporosis, and with the probability of 73.2% the absence of osteoporosis, which can, among other things in our research to some extent, require relative necessity for introduction of antiosteoporotic therapy. The formula is +.214 O +.562 F +.202 R +.223 P +.335 S +.493 T +.057 V +.020. 9. It is necessary to test the formula obtained in examined patients and continue the reseachment, on larger sample, of risk factors which have not shown statistic importance.
Townsend, Katy Louise. "The Use of Radiographs, Dual-energy X-ray Absorptiometry, Quantitative Computed Tomography and Micro-computed Tomography to Determine Local Cancellous Bone Quality in the Canine Proximal Femur". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1336769521.
Texto completoFrazão, Paulo José Riccio. "Estudo da correlação da densidade mineral óssea obtida pelo método de absorciometria radiográfica com a resistência óssea do terceiro metacarpiano de eqüinos submetido a ensaios biomecânicos". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/10/10137/tde-17112008-152015/.
Texto completoThe complete knowledge about non-invasive methods for early disgnostics in equine orthopedy is economicaly important. This experiment has studied the correlation between bone mineral density determined by radiographic absorptiometry and bone resistance of equine third metacarpal bone submitted to both compression and flexion testings. Thirty pairs of third metacarpal bone of adult horses were collected, dissected, radiographed, analysed by the radiographic absorptiometry technique, and submitted to tomographic study and biomechanical testings. The results have shown there is no significant correlation between radiographic bone density values and biomechanical properties of the third metacarpal bone. Therefore, it has been concluded bone mineral density of the third metacarpal bone determined by radiographic absorptiometry do not predict bone capacity to resist compression and flexion loads.
Wirth, Katharina Julia [Verfasser]. "Methodenvergleich von bioelektrischer Impedanz-Analyse und Dual Energy X-ray Absorptiometry zur Detektion von Körperfett und Übergewicht bei Probanden der Berliner Altersstudie II (BASE-II) / Katharina Julia Wirth". Ulm : Universität Ulm. Medizinische Fakultät, 2015. http://d-nb.info/1065309392/34.
Texto completoJunge, Janine [Verfasser], Ingrid [Akademischer Betreuer] Vervuert, Ingrid [Gutachter] Vervuert y Armin [Gutachter] Scholz. "Chemische Zusammensetzung und Knochendichtemessung mit der Dualenergie-Röntgenabsorptiometrie (DEXA, Dual Energy X-Ray Absorptiometry) der Röhrbeine beim Pferd / Janine Junge ; Gutachter: Ingrid Vervuert, Armin Scholz ; Betreuer: Ingrid Vervuert". Leipzig : Universitätsbibliothek Leipzig, 2012. http://d-nb.info/123824064X/34.
Texto completoPompeo, Jaqueline. "Avalia??o da composi??o corporal atrav?s Dual-energy X-ray absorptiometry (DEXA) em rec?m-nascidos de muito baixo peso : efeito do uso de fortificante do leite materno". Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2011. http://tede2.pucrs.br/tede2/handle/tede/1358.
Texto completoINTRODU??O: A Dual-energy X-ray absorptiometry (DEXA) ? considerada o m?todo mais acurado para avalia??o da composi??o corporal. Com o aumento progressivo da sobrevida em prematuros tem ocorrido um interesse crescente em rela??o a avalia??o nutricional, uma vez que uma alimenta??o adequada nas primeiras semanas de vida influencia o desenvolvimento a longo prazo. Portanto a avalia??o da composi??o corporal ? de fundamental import?ncia nos cuidados nutricionais dos prematuros. OBJETIVO: Avaliar a composi??o corporal atrav?s da Dual-energy X-ray absorptiometry em rec?m-nascidos prematuros alimentados com leite humano suplementado (FM85? .Nestl? Nutrition) ou leite humano. M?TODOS: Foram estudados 26 rec?m-nascidos prematuros com menos de 1500g de peso ao nascimento, durante a interna??o na UTI Neonatal do Hospital S?o Lucas da PUCRS, entre julho de 2006 e janeiro de 2010. Os rec?m-nascidos foram randomizados em dois grupos: o grupo 1 recebeu leite humano acrescido de FM85? e o grupo 2 que recebeu leite humano sem FM85?. Foram registrados as medidas antopom?tricas. A composi??o corporal foi avaliada atrav?s da Dual-energy X-ray absorptiometry. RESULTADOS: Foram comparados 15 rec?m-nascidos prematuros que utilizaram leite humano com FM85? e 11 que ingeriram apenas leite humano. Os dois grupos n?o apresentaram diferen?as significativas tanto na entrada como no final do estudo em rela??o a idade gestacional (m?dia 30,2 sem ? 2,38 versus 30 sem ? 1,62; p = 0,76), peso (1232,7 g ? 166,82 versus 1161,4 g ? 228,43; p = 0,37), comprimento (37,4 cm ? 1,9 versus 36,6 cm ? 2,65; p = 0,25) e per?metro cef?lico (26,5 cm ? 2,91 versus 25,9 cm ? 1,51; p = 0,5). As percentagens no in?cio e ao final do estudo n?o apresentaram diferen?a significativa de massa magra (80 ? 1,89 versus 80,3 ? 1,22; p = 0,63), massa gorda (19,6 ? 1,81 versus 19,4 ? 1,2; p = 0,72) e conte?do mineral ?sseo (0,4 ? 0,18 versus 0,3 ? 0,09; p = 0,18), O volume percentual de leite humano ingerido, e tempo de interna??o tamb?m foram semelhantes entre os dois grupos no momento da alta. A concentra??o mineral ?ssea/Kg do grupo FM85? foi maior no grupo do leite humano suplementado (5,46 ? 2,63 g/Kg versus 3,55 ? 1,54 g/Kg; p =0,04) ao final do estudo. CONCLUS?ES: N?o houve diferen?a entre os grupos em rela??o a massa magra, massa gorda e massa mineral ?ssea
SMALLS, LOLA ROMING KELLY. "DEVELOPMENT OF QUANTITATIVE MODELS FOR THE INVESTIGATION OF GYNOID LIPODYSTROPHY (CELLULITE)". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115923913.
Texto completoDean, Maureen A. "Predictions of Distal Radius Compressive Strength by Measurements of Bone Mineral and Stiffness". Ohio University Art and Sciences Honors Theses / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors1461595642.
Texto completoCamargo, Ângela Jordão. "Correlação da qualidade óssea mandibular com a qualidade óssea nas falanges da mão não dominante". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-03112016-201159/.
Texto completoOsteoporosis is a worldwide epidemic, expressed high rates of morbidity and mortality, also resulting in high social costs. Bone densitometry by dual energy X-ray absorptiometry (DXA) is gold standard for the diagnosis of disease, but the low availability of equipment and high costs make it difficult to take, especially in poor and emerging countries. Thus absorptiometry radiographically phalanx (AR) stands out because has low radiation dose, it is simpler using only one hand X-ray and software. Panoramic radiography is widely used in routine dental care worldwide, and has been studied for the evaluation of patients with low bone mineral density (BMD).The aim of this study was to correlate the mandibular bone quality through radiomorphometric indices in panoramic radiograph with bone quality of the non-dominant hand phalanges, through AR. The sample consisted of 167 patients (128 women and 39 men) with a mean age of 52.09 (± 11.5) divided into four groups according to the AR test: Healthy Women (MN) 92; Diseased Women (MD) 36; Men healthy (HN) 25 and Diseased Men (HD) with 14.9. The results showed correlation (p <0.00037) between the Klemetti with RA. Variance analysis IM, IG, MFIs, IFP shown significant differences (p <0.05) between the two groups. Area under the ROC curve was 0.74 (SE = 97.4%, ES = 78%) for MI, 0.79 (SE = 94, ES = 54%) for IG, 0.77 (SE = 94.8%, ES = 64%) for MFIs, 0.76 (SE = 93.1%, ES = 62%) for IFP, 0.71 (SE = 96.5%, ES 86%) for DF. It was concluded that the analysis of radiomorphometric indices showed moderate accuracy for detecting the change in mandibular bone quality according to AR.
Prados, Laura Franco. "Reduction of minerals in feedlot diets of Nellore cattle: impacts on intake, performance, and nutrient requirements; and prediction of chemical rib section composition by dual energy x-ray absorptiometry in Zebu cattle". Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/9214.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
O presente trabalho foi desenvolvido baseado em três estudos. O objetivo do primeiro estudo foi avaliar um novo método para estimar a composição química entre a 9 e 11a seção das costelas (costela9-11) através de equações usando um aparelho de absorptometria radiológica de dupla energia (DXA). O DXA é um método validado usado para caracterizar a composição de tecidos em seres humanos e outros animais, mas poucos estudos avaliaram esta técnica em bovinos de corte e, especialmente, em animais Zebus. Um total de 116 costela9-11 foram utilizadas para desenvolver novos modelos de regressão usando o procedimento de validação cruzada (cross-validation). Para os modelos propostos, 93 costela9-11 foram selecionadas aleatoriamente para gerar as novas equações de regressão, e 23 costela9-11 diferentes foram selecionados aleatoriamente para validar as equações geradas. As seções da costela9-11 de carcaças foram retiradas de animais Nelore e Nelore × Angus de três diferentes experimentos e escaneadas usando o equipamento DXA (GE Healthcare, Madison, Wisconsin, EUA) na Divisão de Saúde da Universidade Federal de Viçosa. Os outputs do relatório do DXA foram DXA massa magra (g), DXA massa livre de gordura (água, proteína e matéria mineral), DXA massa gorda (g), e DXA BMC (conteúdo mineral ósseo; g). Depois de serem escaneadas, as seções das costela9-11 foram dissecadas, liofilizadas, e analisadas para EE, PB, MS e teor de cinzas. Novas equações foram estabelecidas através do procedimento de validação cruzada usando o procedimento REG do SAS. As equações foram como se segue: magro (g) = 37,082 + 0,907 × DXA magra (R2 = 0,95); massa livre de gordura (g) = 103,224 + 0,869 × DXA massa livre de gordura (R2 = 0,93); EE (g) = 122,404 + 1.119 × DXA massa gorda (R2 = 0,86); cinzas (g) = 18,722 + 1,016 × DXA BMC (R2 = 0,39). As equações foram validadas pelo teste de Mayer (teste conjunto do intercepto e inclinação), o coeficiente de correlação e concordância (CCC), e a decomposição do quadrado médio do erro predição (MSEP). Comparando valores observados e preditos usando as novas equações propostas, o teste de Mayer foi não significativo para a massa magra (P = 0,26), massa livre de gordura (P = 0,67), EE (P = 0,054), e cinzas (P = 0,14). Concluiu-se que a composição da costela9-11 de novilhos Nelore e Nelore × Angus pode ser estimada a partir do DXA usando as equações propostas. O segundo estudo foi desenvolvido utilizando novilhos Nelore desmamados (n = 36; 274 ± 34 kg) em delineamento em blocos casualizados em arranjo fatorial 2 × 2, para avaliar o consumo, a excreção fecal e desempenho com diferentes níveis de minerais na dieta de terminação. O experimento incluiu dois níveis de Ca e P (fator macro mineral; CaP+ ou CaP-) e dois níveis de micro minerais (fator micro mineral; ZnMnCu + ou ZnMnCu-). O fator CaP- foi sem suplementação de calcário e fosfato bicálcico e o fator ZnMnCu- foi sem suplementação inorgânica de micro minerais (premix). As dietas foram isoprotéicas (13,3% PB). A ingestão foi monitorada individualmente todo dia. A fibra em detergente neutro indigestível foi usada como indicador interno para calcular a digestibilidade. Os animais foram abatidos em diferentes períodos (84 e 147 dias de confinamento), características de carcaça foram medidas e amostras de fígado e ossos da costela foram retirados. Amostras de alimentos, fezes, costelas e fígado foram analisadas para MS, cinzas, PB, EE, Ca, P, e micro minerais (Zn, Mn e Cu). Não houve interação significativa (P ≥ 0,06) entre a suplementação de macro e micro minerais para todas as variáveis estudadas. Concentração de Ca, P e micro minerais na dieta não afetou (P ≥ 0,20) os consumos de MS, MO, FDN, EE, PB e CNF. Ingestão de Ca e P foram influenciados (P <0,01) pelo fator macro mineral. Animais alimentados sem suplementação de Ca e P consumiram menores quantidades destes minerais. A excreção de matéria seca e de nutrientes foram similares (P ≥ 0,23) entre os fatores estudados. Desempenho e características de carcaça foram similares (P ≥ 0,09) entre as dietas. O teor de cinzas nos ossos das costelas não foi afetado (P ≥ 0,06) pelas dietas. O fósforo e a concentração de fosfatase alcalina no plasma foram semelhantes (P ≥ 0,52) entre as dietas. A concentração plasmática de cálcio foi afetada (P < 0,01) pelo fator micro mineral; no entanto, todos os metabólitos do sangue analisados estavam dentro dos valores de referência. A excreção fecal de Ca e P foi diferente (P < 0,01) entre o fator macro mineral. Estes resultados indicam que a suplementação de minerais (Ca, P, Zn, Mn e Cu) não é necessária em dietas convencionais de confinamento para animais Nelore em terminação. A redução nas dietas destes minerais representaria uma diminuição nos custos de dietas de confinamento. Reduções nas concentrações de Ca e P na dieta pode diminuir a excreção fecal destes minerais. Diminuir a excreção fecal de P através da diminuição deste mineral na dieta é uma oportunidade para reduzir o impacto ambiental dos confinamentos. O terceiro estudo teve como objetivo avaliar o consumo de água, a composição química corporal, o consumo alimentar residual e ganho residual conjunto, e as exigências nutricionais de energia, proteína para mantença e ganho, e cálcio e fósforo para a mantença de novilhos da raça Nelore, bem como suas eficiências. Foram utilizados animais Nelore desmamados (n = 44; 273 ± 34 kg), os novilhos foram alimentados em um delineamento em blocos casualizados em arranjo fatorial 2 × 2 com ausência ou presença de suplementação mineral (Ca, P, Zn, Mn e Cu). O experimento incluiu dois níveis de Ca e P (fator macro mineral; CaP+ ou CaP-) e dois níveis de micro minerais (fator micro mineral; ZnMnCu+ ou ZnMnCu- ). As dietas foram isoprotéicas (13,3% PB). A ingestão foi monitorada individualmente todo dia. Fibra em detergente neutro indigestível foi usada como indicador interno para mensurar a digestibilidade. Quatro animais foram utilizados no grupo de referência (abatidos no dia 0); quatro novilhos foram alimentados ao nível de mantença (1,3% do peso corporal); e os 36 animais restantes foram alimentados ad libitum. Após o abate, as amostras de todo o corpo foram amostradas. Todas as amostras foram liofilizadas, moídas com nitrogênio líquido e agrupadas como percentagem do peso de corpo vazio (PCVZ) de cada animal. As amostras foram analisadas para MS, cinzas, PB, EE, Ca e P. O consumo de água foi semelhante (P ≥ 0,07) entre os tratamentos. A média de ingestão de água livre foi de 17 L/d. O consumo alimentar residual e ganho residual conjunto (GCAR) alto de touros tiveram menor CMS (P < 0,01) do que touros de baixo GCAR, mas com GMD semelhante (P = 0,82). A PB, EE e água presente no PCVZ aumentou à medida que o animal cresceu, o crescimento de cinzas foi menor do que o PCVZ. Equações de regressão não-lineares foram desenvolvidos para predizer a produção de calor, o consumo de energia metabolizável (CEM) e a energia retida (ER). As exigências líquidas de energia para mantença (ELm) e energia metabolizável para mantença (EMm) foram 66,5 e 107 kcal/PCVZ0,75/d, respectivamente. A eficiência (km) foi de 62%. A equação obtida para energia líquida para ganho (ELg) foi: ELg (Mcal/dia) = 0,0388 × PCVZ0,75 × GPCVZ1.095 e a eficiência foi de 25%. Para a proteína líquida para ganho obteve-se: PLg (g/dia) = 179,74 × GPCVZ - 5,43 × ER. A exigência de mantença líquida do Ca foi de 2,33 mg/PCVZ e de P foi de 9,10 mg/PCVZ. O coeficiente de absorção de Ca foi de 54% e do P de 64%. Em conclusão, a exigência de energia líquida para mantença de bovinos Nelore confinados é 66,5 kcal/PCVZ0,75/dia. Exigências de energia líquida para ganho e de proteína líquida para ganho podem ser obtidas através das seguintes equações: ELg (Mcal/dia) = 0,0388 × PCVZ0,75 × GPCVZ1.095 e PLg (g/dia) = 179,74 × GPCVZ - 5,43 × ER. Exigência de mantença líquida do Ca é 2,33 mg/PCVZ e para o P é 9,10 mg/PCVZ. O coeficiente de absorção do Ca é de 54% e do P é de 64%. O consumo de água não é influenciado pela suplementação de Ca, P, Zn, Mn e Cu. Animais que possuem alto consumo alimentar residual e ganho residual conjunto tem menor CMS que animais que apresentam baixo GCAR, e apresentando o mesmo ganho de peso. A PB, EE e água presente no PCVZ aumenta à medida que o animal cresce, o crescimento de cinzas não segue o mesmo padrão que o PCVZ. No geral, o consumo e o desempenho de animais Nelore em terminação confinados não foram afetados pela redução de minerais (Ca, P, Zn, Mn e Cu) na dieta. Concluiu-se que a redução dos teores de minerais em dietas de confinamento para Nelore em terminação não influencia no consumo, desempenho, composição química corporal e exigências nutricionais de bovinos Nelore terminados em confinamento.
The present work was developed based on three studies. The objective of the first study was to evaluate a method to predict the 9th to 11th rib section (rib9-11) composition through empirical equations using Dual Energy X-ray Absorptiometry (DXA). DXA is a validated method used to describe tissue composition in humans and other animals, but few studies have evaluated this technique in beef cattle, and especially in the Zebu genotype. A total of 116 rib9-11 sections were used to evaluate published prediction equations for rib9-11 composition and to develop new regression models using a cross-validation procedure. For the proposed models, 93 ribs were randomly selected to calculate the new regression equations, and 23 different ribs were randomly selected to validate the regressions. The rib9-11 sections from left carcasses were taken from Nellore and Nellore × Angus bulls from three different studies and scanned using DXA equipment (GE Healthcare, Madison, Wisconsin, USA) in the Health Division at Universidade Federal de Viçosa. The outputs of the DXA report were DXA lean (g), DXA fat free mass (g), DXA fat mass (g), and DXA BMC (bone mineral content; g). After being scanned, the rib9-11 sections were dissected, grounded, and chemically analyzed for total EE, CP, water, and ash content. The predictions of rib fat and protein from previous published equations were different (P < 0.01) from the observed composition. New equations were established through leave-one-out cross-validation using REG procedure using SAS. The equations were as follows: Lean (g) = 37.082 + 0.907× DXA lean (R 2 = 0.95); Fat free mass (g) = 103.224 + 0.869 × DXA fat free mass (R2 = 0.93); EE mass (g) = 122.404 + 1.119 × DXA fat mass (R2 = 0.86); Ash mass (g) = 18.722 + 1.016 × DXA BMC (R2 = 0.39). The equations were validated using Mayer’s test, the concordance correlation coefficient (CCC), and the mean square error of prediction (MSEP) for decomposition. Comparing observed and predicted values using the new equations, Mayer’s test was not significant for lean mass (P = 0.26), fat free mass (P = 0.67), EE mass (P = 0.054), and ash mass (P = 0.14). We concluded that the rib9-11 composition of Nellore and Nellore × Angus bulls can be estimated from DXA using the proposed equations. The second study was developed using weaned Nellore bulls (n = 36; 274 ± 34 kg) in a randomized complete block 2 × 2 factorial design experiment to evaluate intake, fecal excretion and performance with different levels of minerals. The design included two levels of Ca and P (macro mineral factor; CaP+ or CaP-) and two levels of micro minerals (micro mineral factor; ZnMnCu+ or ZnMnCu-). The factor CaP- was without supplementation of limestone and dicalcium phosphate and the factor ZnMnCu- was without inorganic supplementation of micro minerals. The diets were isonitrogenous (13.3% CP). Intake was individually monitored every day. Indigestible NDF was used as an internal marker for fecal excretion measurements. The animals were slaughtered (84 and 147 days on feed; DOF), carcass characteristics were measured and liver and rib samples were collected. Feed, feces, rib bones and liver samples were analyzed for DM, ash, CP, EE, Ca, P, and micro minerals (Zn, Mn, and Cu). There were no significant interactions (P ≥ 0.06) between macro and micro minerals supplementation for any variables in the study. Calcium, P and micro minerals concentrations did not affect (P ≥ 0.20) intakes of DM, OM, NDF, EE, CP, TDN and NFC. Calcium and P intake were affected (P < 0.01) by macro mineral factor. Animals fed without Ca and P supplementation consumed lower levels of these minerals. Dry matter and nutrient fecal excretion were similar (P ≥ 0.23) among factors. Performance and carcass characteristics were similar (P ≥ 0.09) among diets. The content of ash in rib bones was not affected (P ≥ 0.06) by diets. Phosphorus and phosphatase alkaline plasma concentration were similar (P ≥ 0.52) among diets. Calcium plasma concentration was affected (P < 0.01) by micro mineral factor; nevertheless, all blood metabolites were within the reference values. Fecal excretion of Ca and P was different (P < 0.01) among macro mineral factor. These results indicate that supplementation of minerals (Ca, P, Zn, Mn, and Cu) is not necessary in conventional feedlot diets for finishing Nellore. Dietary reductions in these minerals would represent a decrease in the costs of feedlot diets. Dietary reductions in Ca and P decrease fecal excretion of these minerals. Decreasing the P fecal excretion through decreasing content minerals is an opportunity to reduce environmental impact of feedlot operations. The third study aimed to evaluate the water intake, the chemical body composition, the residual feed intake and gain, and the nutritional requirements of energy, protein for maintenance and gain, and calcium and phosphorus for maintenance of Nellore bulls, as well as their efficiencies. Weaned Nellore bulls (n = 44; 273 ± 34 kg) were fed in a randomized complete block design 2 × 2 factorial arrangement to evaluate the nutritional requirements with absence or presence of mineral supplementation. The design included two levels of Ca and P (macro mineral factor; CaP+ or CaP-) and two levels of micro minerals (micro mineral factor; ZnMnCu+ or ZnMnCu-). The diets were isonitrogenous (13.3% CP). Intake was individually monitored every day. Indigestible NDF was used as an internal marker for digestibility measurements. Four animals were used in the reference group (harvested d 0); four bulls were fed at the maintenance level (1.1% of BW); and the remaining 36 bulls were fed ad libitum. Bulls are blocked by days on fed, they were slaughtered on d 84 and 147, after slaughter, samples of the whole body were taken. All samples were lyophilized, ground with liquid nitrogen and grouped as percentage of component in empty BW from each bull. Samples were analyzed for DM, ash, CP, EE, Ca, and P. The water intake was similar (P ≥ 0.07) among treatments. The average of free water intake was 17 L/d for each bull. High residual feed intake and gain (RFIG) bulls had lower DMI (P < 0.01) than low RFIG bulls, but similar ADG (P = 0.82). The CP, EE and water present in the EBW increased as the animal grew, the ash growth is lower than the EBW. Non-linear regression equations were developed to predict heat production (HP) from metabolizable energy (ME) intake and retained energy (RE). The net energy requirements for maintenance (NEm) and metabolizable energy for maintenance (MEm) were 66.5 and 107 kcal/EBW0.75/d, respectively. The efficiency (km) was 62%. The equation obtained for net energy for gain (NEg) was: NEg (Mcal/day) = 0.0388 × EBW0.75 × EBWG1.095 and the efficiency was 25%. For net protein for gain was: NPg (g/day) = 179.74 × EBWG – 5.43 × RE. The net maintenance requirement for Ca was 2.33 mg/EBW and for P was 9.10 mg/EBW. The coefficient of absorption for Ca was 54% and P was 64%. In conclusion, the requirement of net energy for maintenance for Nellore feedlot cattle is 66.5 kcal/EBW0.75/day. Requirements of net energy for gain and net protein for gain can be obtained by the following equations: NEg (Mcal/day) = 0.0388 × EBW0.75 × EBWG1.095 and NPg (g/day) = 179.74 × EBWG – 5.43 × RE. Net maintenance requirement for Ca is 2.33 mg/EBW and for P is 9.10 mg/EBW. The coefficient of absorption for Ca is 54% and P is 64%. The water intake is not influenced by supplementation of Ca, P, Zn, Mn, and Cu. High residual feed intake and gain bulls has lower DMI than low RFIG bulls, with similar ADG. The CP, EE and water present in the EBW increased as the animal grew, the ash growth is lower than the EBW. Overall, intake and performance was not affect by minerals (Ca, P, Zn, Mn, and Cu) diet reduction. It was concluded that the reduction of minerals contents in feedlot diets for Nellore finishing bulls appears not influence in intake, performance, chemical body composition, and nutrient requirements of Nellore finishing bulls in feedlot.
Venturini, Ana Claudia Rossini. "Metabolismo energético multicompartimental: modelos preditivos derivados da DXA". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/109/109131/tde-02042018-164553/.
Texto completoResting Energy Expenditure (REE) varies over time and has practical consequences for interpersonal comparisons. The traditional method to estimate REE does not take into account the metabolic activities of organs, bone tissue (BT), adipose tissue (AT), muscle tissue (MT) and brain. Therefore, the aim of this study was to determine the REE of Brazilian young adults from a multicompartmental way (DXA) referenced by indirect calorimetry (IC). A sample of 155 university students of both sexes (18-30 years) was submitted to anthropometric measurements, to estimate REE by IC and total body scan (DXA) of the molecular level. After transformation of DXA components to the organ-tissue level, the REE was determined for each component. The agreement (Bland-Altman) between measured REE (CI) and predicted (DXA) was carried out to validate the tested model. How validation failed, a new model was developed (Linear Regression - ENTER) and validated (PRESS) having as dependent variable the five variables generated after the relativization of the GER given by the IC for the model tested plus the sex variable. The analyzes were performed with the statistical package SPSS v. 20.0 (Chicago, IL); MedCalc® 2015 (v.15.2); and Minitab® (see 17.3.1), with significance level at ? = 0.05. The results showed higher values of adipose tissue free mass (ATFM), head area and residual tissue (RT) for men and lower values of fat mass (MG) and adipose tissue (AT) in relation to women. Higher expenditure (p <0.001) were found in men for all components compared to women, except for AT (p <0.001). In the comparisons between measured and predicted differences (p <0.001) were found for the total sample, men and women. In this way, specific equations for each component were proposed and validated by the sum of the squares of the residues, in the coefficients (R2PRESS = 0.95, 0.73, 0.80, 0.16, 0.84) and the reduced error reliability (SPRESS = 14.2, 1.8, 46.3, 48.1, 87.2) for the expenditure of AT, BT, MT, brain and RT. In conclusion, this approach has important implications for the evaluation and interpretation of multicompartmental energy metabolism considering the interpersonal differences in the production of heat. It is a strategy applicable in the context of health or sports, for prescription of exercises or manipulation of diets, as it portrays the magnitude of GER of each body component