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Relationship between the somatic cell count in raw milk and the casein fractions of UHT milk

FERNANDES, Andrezza Maria; BOVO, Fernanda; MORETTI, Thais Santos; ROSIM, Roice Eliana; LIMA, Cesar Goncalves de; OLIVEIRA, Carlos Augusto Fernandes de
Fonte: DAIRY INDUSTRY ASSOC AUSTRALIA Publicador: DAIRY INDUSTRY ASSOC AUSTRALIA
Tipo: Artigo de Revista Científica
Português
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25.89%
The relationship between somatic cell count (SCC) in raw milk and casein fractions of 15 batches of the corresponding ultra-high-temperature (UHT) milk was examined. Raw milk was collected, pasteurised and submitted to UHT treatment. Samples of the UHT milk were taken on days 8, 30, 60, 90 and 120 of storage at room temperature and their casein fractions analysed by high performance liquid chromatography. SCC ranged from 197,000 to 800,000 cells/mL. No correlation (p>0.05) was found between SCC and K-casein concentrations in raw or UHT milks. The alpha(s2) and P-casein concentrations in raw milk were negatively correlated with SCC (p<0.05). In UHT milk, negative correlations were observed for a,1-casein (p<0.05) and beta-casein (p<0.05) on the 8th day, and for alpha S-2-casein (p<0.01) on the 60th day of storage. Results indicate that higher SSC in raw milk is associated with substantial degradation of beta-casein and alpha(s)-casein, which may lead to quality defects in UHT milk during storage. Aust. J. Dairy Technol. 63, 45-49; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Brazil[2004/01261 - 3]

Effect of electrolyte on the gelation and aggregation of SnO2 colloidal suspensions

Hiratsuka, Renato Satoshi; Santilli, Celso Valentim; Silva, Dileize Valeriano; Pulcinelli, Sandra Helena
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 67-73
Português
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Electrolytes may modify the physical-chemical characteristics of colloidal particle interfaces in suspension, which can favour gel or aggregate formation. The influence of NH4Cl loading on the aggregation and gelation of SnO2 colloidal suspensions was investigated using measurements of rheology, turbidity and infrared spectra. A rapid aggregate growth for samples with Cl- > 20 mM was observed. With increasing age, gelation was observed due to formation of interaggregate bonds. For concentration of Cl- between 20 and 9 mM, the aggregation process was slower allowing the formation of gel with a network which was not destroyed as the gel was submitted to a small rate of shear. As aging continues, the condensation reaction between OH groups gave rise to the formation of Sn-O bonds, irrespective of the electrolyte loading. © 1992 Elsevier Science Publishers B.V. All rights reserved.

Adição de dioxido de carbono ao leite cru : efeito sobre a qualidade e vida de prateleira do leite UHT; Carbon dioxide addition to raw milk : effect on the quality and shelf-life of UHT milk

Priscila Cristina Bizam Vianna
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 23/04/2010 Português
Relevância na Pesquisa
25.89%
O objetivo deste trabalho foi avaliar o efeito da adição de dióxido de carbono (CO2) sobre a qualidade dos leites cru e UHT. Inicialmente, o leite cru adicionado ou não de CO2 foi armazenado em garrafas de vidro a 4 e 7ºC e amostras foram avaliadas diariamente quanto à contagem padrão em placas, psicrotróficos e Pseudomonas spp. e a cada dois dias quanto à concentração de CO2, proteólise e lipólise, até que a contagem padrão em placas atingisse 7,5x105 ufc/mL. O delineamento experimental utilizado foi o de sub-sub-parcelas divididas e os resultados foram avaliados por análise de variância multivariada, pelo teste de médias de Tukey (p<0,05) e através do modelo matemático de Gompertz. A contagem padrão aumentou ao longo do tempo para todos os tratamentos e o tempo de conservação foi de 14 dias para o leite armazenado a 4ºC adicionado de CO2 e de 5 dias para o armazenado a 7ºC não adicionado de CO2. Independente da temperatura de armazenamento, a adição de CO2 estendeu o tempo de fase lag e de geração dos micro-organismos psicrotróficos e reduziu sua taxa de crescimento. O leite adicionado de CO2 apresentou menor proteólise e lipólise quando comparado ao não adicionado devido ao menor desenvolvimento de psicrotróficos. Com base nesses resultados...

Efeito da adição de CO2 ao leite cru sobre as características do leite UHT armazenado a diferentes temperaturas; Effect of carbon dioxide addition to raw milk on the characteristics of UHT milk stored at different temperatures

Maria Elisabete Fernandes Dias
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 20/12/2011 Português
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25.89%
O objetivo deste trabalho foi avaliar o efeito da adição de CO2 ao leite cru sobre as características do leite UHT obtido por injeção direta de vapor e armazenamento a 25ºC, 35ºC e 45ºC por 180 dias. O leite cru (250 litros) foi dividido em duas porções que foram armazenadas em tanques de expansão a 4?1ºC por seis dias. Uma porção foi adicionada de CO2 grau alimentício até que o pH do leite atingisse 6,20, enquanto a outra serviu de controle. O leite cru foi avaliado quanto ao pH, acidez, prova do álcool, composição físico-química, proteólise, lipólise, cor e concentração de CO2 após a injeção. Para caracterização microbiológica, o leite cru foi avaliado quanto à contagem padrão em placas e de micro-organismos psicrotróficos no dia da recepção e após seis dias de armazenamento refrigerado. As amostras foram submetidas ao tratamento UHT por injeção direta de vapor (143ºC/4s), envasadas em embalagens tetra brik asseptic de 125 ml e armazenadas em BOD a 25, 35 e 45 ºC por 180 dias. No dia seguinte, as amostras foram avaliadas quanto as mesmas características do leite cru, além da prova do álcool, viscosidade, sedimentação, eletroforese, peptídeos por HPLC e esterilidade comercial. Após 1...

Desenvolvimento e testes in vitro de nanopartículas de quitosana para liberação controlada de peptídeos antitumorais

Medeiros, Kelliane Almeida de
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Dissertação
Português
Relevância na Pesquisa
15.89%
Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Animal, 2011.; As alternativas comuns para o tratamento do câncer têm sido a quimioterapia e a radioterapia apesar destas terapias destruírem células tumorais e não tumorais, sendo necessária a busca por novas alternativas. Entretanto, muitas novas moléculas também podem causar toxicidade em células não tumorais, sendo necessários seus encapsulamentos em sistemas de liberação controlada. Uma das estratégias para a liberação controlada é o uso de nanopartículas com composição e natureza variadas para confinar o composto. O presente estudo tem como objetivo identificar peptídeos com função antitumoral a partir de bibliotecas de sequências (EMBRAPA) de moléculas, encapsular os peptídeos em nanopartícula contendo em sua composição quitosana e desenvolver um sistema de liberação controlada em células tumorais. Foram selecionados dois peptídeos encontrados em anfíbios (H-ALWKDLLKNVGIAAGKAVLNKVTDMVNQ-OH e H-YIGWGYHDY-OH), um fragmento de uma proteína supressora de metástase (H-FINKAGKLQSQLRTTVVAAAAFLDAFQKVA-NH2) e um peptídeo de veneno de abelha, como controle positivo (H-GIGAVLKVLTTGLPALISWIKRKRQQ-NH2). Os peptídeos foram sintetizados manualmente pelo método da fase sólida e purificados em RP-HPLC. Tiveram pureza e identidade molecular aferidas em espectrômetro de massa MALDI-TOF/TOF e foram avaliados quanto à eficácia e potência in vitro contra as linhagens de células tumorais B16F10...

Novel bilayered Gellan gum/Gellan gum hydroxyapatite scaffolds for osteochondral tissue engineering applications

Canadas, Raphael Faustino; Pereira, D. R.; Correia, Joana Silva; Marques, A. P.; Oliveira, Joaquim M.; Reis, R. L.
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Conferência ou Objeto de Conferência
Publicado em /10/2012 Português
Relevância na Pesquisa
15.89%
Osteoarthritis is a major cause of disability during aging. By the age of 60, close to 100% of the population will have histologic changes of degeneration in their knee cartilage (Loeser, 2000). Because of its avascular nature, cartilage has little capacity to self-regenerate. Despite the progress already achieved in osteochondral regeneration, some limitations have to be overcome. The formation of fibrocartilage has to be avoided and the innervation has to be improved. Further, one main feature to be promoted is the induction of vascularization in the bony part but not in the cartilage part and to avoid de-differentiation processes. A promising strategy could pass through the development and optimization of novel culture systems. The ideal approach could integrate scaffolds presenting regions with different physical characteristics, combined with different growth factors to support different stem cells fates, regarding the complex tissue physiology to be regenerate. This work aims to develop novel bilayered gellan gum (GG)/gellan gumhydroxyapatite (HAp) hydrogels based structures for osteochondral tissue engineering applications. Bilayered GG/GG-HAp hydrogels were produced by joining both solutions of GG 2% (w/v) with and without HAp (20% wt.) for bony and cartilage parts...

Possible Role of Coryneform Bacteria in Age Gelation of Ultrahigh-Temperature-Processed Milk

Keogh, Barbara P.; Pettingill, G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1982 Português
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46.35%
Two strains of psychrotrophic, gram-positive, proteolytic bacteria isolated from raw milk were identified as Arthrobacter or closely related coryneform species. We inoculated raw-milk samples with the strains (one strain per sample) and compared rates of gelation after ultrahigh-temperature processing with that of ultrahigh-temperature-processed controls. The trial indicated that either organism could play a role in age gelation of ultrahigh-temperature-processed milk.

Mutations in the γ-Actin Gene (ACTG1) Are Associated with Dominant Progressive Deafness (DFNA20/26)

Zhu, M.; Yang, T.; Wei, S.; DeWan, A. T.; Morell, R. J.; Elfenbein, J. L.; Fisher, R. A.; Leal, S. M.; Smith, R. J. H.; Friderici, K. H.
Fonte: The American Society of Human Genetics Publicador: The American Society of Human Genetics
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
15.99%
Age-related hearing loss (presbycusis) is a significant problem in the population. The genetic contribution to age-related hearing loss is estimated to be 40%–50%. Gene mutations that cause nonsyndromic progressive hearing loss with early onset may provide insight into the etiology of presbycusis. We have identified four families segregating an autosomal dominant, progressive, sensorineural hearing loss phenotype that has been linked to chromosome 17q25.3. The critical interval containing the causative gene was narrowed to ∼2 million bp between markers D17S914 and D17S668. Cochlear-expressed genes were sequenced in affected family members. Sequence analysis of the γ-actin gene (ACTG1) revealed missense mutations in highly conserved actin domains in all four families. These mutations change amino acids that are conserved in all actins, from protozoa to mammals, and were not found in >100 chromosomes from normal hearing individuals. Much of the specialized ultrastructural organization of the cells in the cochlea is based on the actin cytoskeleton. Many of the mutations known to cause either syndromic or nonsyndromic deafness occur in genes that interact with actin (e.g., the myosins, espin, and harmonin). The mutations we have identified are in various binding domains of actin and are predicted to mildly interfere with bundling...

Physiologically relevant, pH-responsive PEG-based block and statistical copolymers with N,N-diisopropylamine units†

Lee, Annabelle; Lundberg, Pontus; Klinger, Daniel; Lee, Bongjae F.; Hawker, Craig J.; Lynd, Nathaniel A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
16.04%
In order to impart pH-responsiveness within a physiologically-relevant context to PEG-based biomaterials, a new tertiary amine containing repeat unit, N,N-diisopropyl ethanolamine glycidyl ether (DEGE), was developed and incorporated into statistical and block copolymers with ethylene oxide (EO), and allyl glycidyl ether (AGE) via anionic ring-opening polymerization. The reactivity of this novel monomeric building block in copolymerizations with EO was investigated by spectroscopy with observed reactivity ratios of rDEGE = 1.28 ± 0.14 and rEO = 0.82 ± 0.10. It was further demonstrated that DEGE containing copolymers could serve as building blocks for the formation of new pH-responsive materials with a pKa of ca. 9, which allowed macroscopic hydrogels to be prepared from symmetric triblock copolymers PDEGE5.3k-b-PEO20k-b-PDEGE5.3k. The triblock copolymers exhibited clear sol-to-gel transitions in a physiologically-relevant critical gelation range of pH 5.8–6.6 and pH-dependent viscoelastic properties. On the nanometer scale, the preparation of pH-responsive micro- or nanogels was demonstrated by crosslinking P(DEGE-co-AGE) copolymers in miniemulsion droplets stabilized by PEO-b-P(DEGE-co-AGE) diblock terpolymers. These nanoparticles exhibited a reversible pH-dependent swelling profile with a volume phase transition at physiological pH 6.5–7.5.

Avaliação das características físico-químicas e alterações do leite UHT (UAT) produzido no Estado de Goiás ao longo da estocagem; Avaliação das características físico-químicas e alterações do leite UHT (UAT) produzido no Estado de Goiás ao longo da estocagem

COSTA, Andréia Di Martins Carmo
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Ciência e Tecnologia de Alimentos; Ciencias Agrárias - Agronomia Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Ciência e Tecnologia de Alimentos; Ciencias Agrárias - Agronomia
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
25.89%
With the objective of evaluating the physical/chemical, microbiological characteristics and the changes that occur in UHT milk (UAT) processed in the State of Goias during its storage for 135 days, a study was done between August and December 2008 with all the companies that produced UHT milk (UAT) processed in the State. Samples were collected from refrigerated raw milk stored in milk storage silos of industry for analysis of their physical/chemical and microbiological characteristics. From each company, twelve one liter cartons of milk were collected for analysis of their physical/chemical and microbiological properties as well as nitrogen compounds and the amount of fat separation from the milk and sedimentation within each sample. The samples were sent to the laboratories of Microbiology and Dairy of the School of Agronomy and Food Engineering at the Federal University of Goias (UFG). The physico-chemical properties of raw milk were in accordance with the parameters established by legislation, except for three brands of milk, with values of freezing point, nonfat milk solids and total solids. The Alizarol test results were normal for UHT milk (UHT) of all brands, except the milk of the mark "E", which has had worst results established by legislation. All milk samples were within the standards for titratable acidity and pH. The density indices were normal...

Aging of the Nonlinear Optical Susceptibility of colloidal solutions

Ghofraniha, Neda; Conti, Claudio; Ruocco, Giancarlo
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/09/2006 Português
Relevância na Pesquisa
16.13%
Using Z-scan and dynamic light scattering measurements we investigate the nonlinear optics response of a colloidal solution undergoing dynamics slowing down with age. We study the high optical nonlinearity of an organic dye (Rhodamine B) dispersed in a water-clay (Laponite) solution, at different clay concentrations (2.0 wt% - 2.6 wt%), experiencing the gelation process. We determine the clay platelets self diffusion coefficient and, by its comparison with the structural relaxation time, we conclude that the gelation process proceeds through the structuring of interconnecting clay platelets network rather than through clusters growth and aggregation.; Comment: 4 figures, 4 pages

Laminin-Functionalized Polyethylene Glycol Hydrogels for Nucleus Pulposus Regeneration

Francisco, Aubrey Therese
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2013 Português
Relevância na Pesquisa
16.13%

Intervertebral disc (IVD) disorders and age-related degeneration are believed to contribute to low back pain. There is significant interest in cell-based strategies for regenerating the nucleus pulposus (NP) region of the disc; however, few scaffolds have been evaluated for their ability to promote or maintain an immature NP cell phenotype. Additionally, while cell delivery to the pathological IVD has significant therapeutic potential for enhancing NP regeneration, the development of injectable biomaterials that retain delivered cells, promote cell survival, and maintain or promote an NP cell phenotype in vivo remains a significant challenge. Previous studies have demonstrated NP cell - laminin interactions in the NP region of the IVD that promote cell attachment and biosynthesis. These findings suggest that incorporating laminin ligands into biomaterial scaffolds for NP tissue engineering or cell delivery to the disc may be beneficial for promoting NP cell survival and phenotype. In this dissertation, laminin-111 (LM111) functionalized poly(ethylene glycol) (PEG) hydrogels were developed and evaluated as biomaterial scaffolds for cell-based NP regeneration.

Here, PEG-LM111 conjugates with functional acrylate groups for crosslinking were synthesized and characterized to allow for protein coupling to both photocrosslinkable and injectable PEG-based biomaterial scaffolds. PEG-LM111 conjugates synthesized using low ratios of PEG to LM111 were found support NP cell attachment and signaling in a manner similar to unmodified LM111. A single PEG-LM111 conjugate was conjugated to photocrosslinkable PEG-LM111 hydrogels...

REVISÃO: LEITE UHT E O FENÔMENO DE GELATINIZAÇÃO

CUNHA, MÁRCIO FERRAZ
Fonte: UFPR Publicador: UFPR
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 09/12/2005 Português
Relevância na Pesquisa
46.51%
Descreve-se neste artigo de revisão, o tratamento térmico “ultra-high-temperature” (UHT), empregado no processamento do leite, bem como seu efeito sobre alguns nutrientes (vitaminas). Também são discutidos os mecanismos envolvidos na gelatinização deste produto, fenômeno que pode reduzir sua vida útil. Em virtude de aumento no consumo do leite UHT e sua importância econômica torna-se indispensável estudar os mecanismos físicos, químicos e bioquímicos relacionados com o fenômeno de gelatinização. REVIEW: UHT MILK AND THE AGE GELATION PHENOMENA Abstract In this review article the ultra-high-temperature treatment in milk processing is described, as well as its effects in some nutrients (vitamins). The mechanisms involved in the age gelation of this product, phenomena that can reduce shelf-life of UHT milk, is discussed. By reason of the increase consumption of UHT milk and your economic importance in Brazil is absolutely necessary future researches of the physical, chemical and biochemical mechanisms related to the age gelation phenomena.