47 research outputs found
Preparation and Characterization of LAS Glass Based Materials for Dental Applications
Glass ceramic materials are widely used in dental application because of their strong
similarity with natural teeth. In this study LAS glass ceramic/glass materials were prepared by
glazing processing and characterized in terms of mechanical flexural strength. The selected glass
ceramic support derives from an industrial process. Different glasses were applied to the glass
ceramic support in order to investigate firstly their effect on the glass ceramic/glass interface and
secondly how these structural changes are correlated to the flexural strength property. Different
thermal cycles were applied to the glass ceramic in order to promote the increasing of mechanical
flexural strength. Preliminary results clearly points out that the application of a glass on the support
leads to the decrease of the flexural strength if compared to the materials without any coating
applied
Recycling of yttria-stabilized zirconia waste powders in glazes suitable for ceramic tiles
The aim of this work is to demonstrate the feasibility of valorizing and recycling Yttria-stabilized Zirconia thermal spray waste into high value products for industrial and residential use. Based on the powders chemistry and morphology, this work aims to realize products, like frits suitable for white glazes and ceramic tiles. The focus is on one class of powder: high-temperature and abrasion-resistant ceramics, like Yttria-stabilized zirconia. This study has revealed that the substitution of pure zirconia with waste Yttria-stabilized zirconia is possible in high percentages, up to 100% to prepare frits suitable for white glaze
Acute lobar nephritis in children: Not so easy to recognize and manage
Acute lobar nephritis (ALN) is a localized non-liquefactive inflammatory renal bacterial infection, which typically involves one or more lobes. ALN is considered to be a midpoint in the spectrum of upper urinary tract infection, a spectrum ranging from uncomplicated pyelonephritis to intrarenal abscess. This condition may be difficult to recognize due to the lack of specific symptoms and laboratory findings. Therefore the disease is probably underdiagnosed. Computed tomography scanning represents the diagnostic gold standard for ALN, but magnetic resonance imagine could be considered in order to limit irradiation. The diagnosis is relevant since initial intravenous antibiotic therapy and overall length of treatment should not be shorter than 3 wk. We review the literature and analyze the ALN clinical presentation starting from four cases with the aim to give to the clinicians the elements to suspect and recognize the ALN in children
Učinak mikroinkapsulacije na kemijski sastav te antimikrobna, antioksidacijska i citotoksična svojstva eteričnog ulja limunske trave (Cymbopogon flexuosus)
Research background. Lemongrass (Cymbopogon flexuosus) essential oil exhibits antimicrobial and antioxidant properties due to the presence of α-citral and β-citral. Essential oils are susceptible to volatilization and oxidation when applied to food matrices. Therefore, a barrier is needed to protect this material. The present study aims to produce microparticles containing lemongrass essential oil, with gum arabic and maltodextrin using spray drying technology.
Experimental approach. Lemongrass essential oil was extracted by the hydrodistillation method and later microencapsulated with different wall materials. Free and microencapsulated lemongrass essential oil was evaluated for the cytotoxic activity (using Artemia salina as test sample), chemical composition (GC-MS), encapsulation efficiency, antioxidant activity (DPPH, ABTS and FRAP), antimicrobial activity and minimum inhibitory concentration.
Results and conclusions. The lethal concentration (LC50) of lemongrass essential oil in the cytotoxic test was 8.43 μg/mL against Artemia salina; a high activity that can be associated with the presence of α-citral (~33%) and β-citral (~21%) in the samples, since these were the main compounds with bioactive properties. The highest value of microencapsulation efficiency (88.11%) was obtained when only gum arabic was used as wall material. In general, the microparticles showed satisfactory antioxidant activity (expressed as Trolox equivalents, between 348.66 and 2042.30 µmol/100 g) and bactericidal effect in vitro against Gram-positive and Gram-negative microorganisms. In conclusion, the microencapsulated lemongrass essential oil is a promising functional additive in the food and pharmaceutical industries.
Novelty and scientific contribution. This study shows that microparticles containing lemongrass essential oil can be prepared using gum arabic and maltodextrin as wall materials by spray drying, resulting in high microencapsulation efficiency. The drying process maintained the antimicrobial and antioxidant properties of the essential oil. Therefore, the microencapsulated lemongrass essential oil is considered a natural, functional and promising additive in the food industry. Its antimicrobial action can increase the shelf life of fresh and semi-fresh products such as cheese, yogurts and meat products. In addition, its antioxidant action can delay the lipid and protein oxidation in food products.Pozadina istraživanja. Eterično ulje limunske trave (Cymbopogon flexuosus) sadržava α- i β-citral, zbog čega ima antimikrobni i antioksidacijski učinak. Eterična ulja hlape i oksidiraju nakon dodavanja hrani, pa ih treba zaštititi pomoću omotača. Svrha je ovoga rada bila postupkom sušenja raspršivanjem pomoću gume arabike i maltodekstrina proizvesti mikročestice koje sadržavaju eterično ulje limunske trave.
Eksperimentalni pristup. Eterično ulje limunske trave dobiveno je postupkom hidrodestilacije, nakon čega je mikroinkapsulirano u različitim materijalima. Ispitani su citotoksični učinak (na larvama račića Artemia salina kao testnom uzorku), kemijski sastav (metodom GC-MS), učinkovitost inkapsulacije, antioksidacijski učinak (metodama DPPH, ABTS i FRAP), antimikrobni učinak i minimalna inhibicijska koncentracija eteričnog ulja limunske trave u izvornom obliku te u mikrokapsulama.
Rezultati i zaključci. Smrtonosna koncentracija (LC50) eteričnog ulja limunske trave pri ispitivanju citotoksičnosti na larvama račića bila je 8,43 μg/mL. Povećana citotoksičnost povezuje se sa prisustvom α-citrala (≈33 %) i β-citrala (≈21 %), jer su to glavni spojevi s bioaktivnim svojstvima u uzorcima. Najveća učinkovitost mikroinkapsulacije (88,11 %) postignuta je kad je guma arabika korištena kao materijal za inkapsulaciju. Općenito su mikročestice imale zadovoljavajući antioksidacijski (između 348,66 i 2042,30 µmol/100 g, izraženu u Trolox ekvivalentima) i in vitro baktericidni učinak na Gram-pozitivne i Gram-negativne bakterije. Može se zaključiti da se eterično ulje limunske kiseline može koristiti kao funkcionalni dodatak u prehrambenoj i farmaceutskoj industriji.
Novina i znanstveni doprinos. Istraživanje je pokazalo da se mikročestice eteričnog ulja limunske trave mogu dobiti korištenjem gume arabike i maltodekstrina kao materijala za inkapsulaciju u postupku sušenja raspršivanjem, s velikim učinkom inkapsulacije. Postupkom sušenja raspršivanjem zadržana su antimikrobna i antioksidacijska svojstva eteričnog ulja. Stoga se mikroinkapsulirano eterično ulje limunske trave smatra prirodnim, funkcionalnim i prikladnim dodatkom u prehrambenoj industriji. Njegovo antimikrobno djelovanje može produljiti trajnost svježih i polusvježih proizvoda, kao što su sir, jogurt i mesni proizvodi. Osim toga, njegovo antioksidacijsko djelovanje može usporiti oksidaciju proteina i lipida u prehrambenim proizvodima
Sítios Paleontológicos das Bacias do Rio do Peixe: Georreferenciamento, Diagnóstico de Vulnerabilidade e Medidas de Proteção
The abandoned state and depredation of the paleontological geosites at the Rio do Peixe basins have been for some time a reason for concern to authorities and the society. Removal of sand from the Monumento Natural Vale dos Dinossauros Park and removal of fossils from sites catalogued by SIGEP (Comissão Brasileira de Sítios Geológicos e Paleobiológicos) have been made public and recognized through this study. The aims of this paper are to: georeference the paleontological sites from the Rio do Peixe basins, provide a diagnostic of vunerability for these sites, and establish proposals for protection measures. Ten field work were carried out, in 2008 and 2009, by the technicians from DNPM. Besides a georeferenced map of the paleontological sites from the Rio do Peixe basins, nine factors that strongly contribute for the vulnerability of the sites were defined, the main ones being the natural action of weathering and the antropic action. Most of the studied sites have medium to high vulnerability degree. The most vulnerable site are: Pedregulho, Piau/Caiçara, Várzea dos Ramos, Lagoa dos Patos, Cabra Assada, and Matadouro. Currently, Matadouro Site can be considered a completely destroyed, being, its recovery no longer possible. Ten protection measures were proposed for these paleontological sites.O estado de abandono e depredação dos sítios paleontológicos das bacias do Rio do Peixe é motivo de preocupação para as autoridades e para a sociedade há algum tempo. Denúncias foram feitas e constatadas, tanto de extração de areia no Parque Monumento Natural Vale dos Dinossauros quanto de retiradas de fósseis de sítios cadastrados pela SIGEP (Comissão Brasileira de Sítios Geológicos e Paleobiológicos). O presente trabalho teve como objetivo georreferenciar os sítios paleontológicos das bacias do Rio do Peixe, definir um diagnóstico de vulnerabilidade desses sítios e estabelecer propostas para medidas de proteção. Foram realizadas dez etapas de trabalhos de campo, nos anos de 2008 e 2009, com o revezamento de técnicos do DNPM. Além de um mapa georreferenciado, com os sítios paleontológicos das bacias do Rio do Peixe, foram definidos nove fatores que contribuem mais acentuadamente para a vulnerabilidade dos sítios, sendo que a ação natural do intemperismo e a ação antrópica são os dois principais. A maioria dos sítios estudados possui vulnerabilidade de média a alta, sendo que os sítios com maior vulnerabilidade são: Pedregulho, Piau/Caiçara, Várzea dos Ramos, Lagoa dos Patos, Cabra Assada e Matadouro. Entre eles, atualmente, o Sítio Matadouro pode ser considerado como um sítio destruído, não sendo possível a sua recuperação. Dez propostas foram estabelecidas como medidas de proteção desses sítios paleontológicos
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Amido de sementes de nêspera : avaliação de compostos bioativos, atividade antioxidante, propriedades térmicas, reológicas e morfológicas
Orientadora : Profª Drª Rosemary Hoffmann RibaniDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Alimentos. Defesa : Curitiba, 02/03/2018Inclui referências : p. 85-93Resumo: A investigação de fontes de amido não convencionais é essencial porque diferentes composições químicas, tamanhos granulares, formas e proporções de amilose e amilopectina revelam novas características tecnológicas. A nêspera, planta da família das Rosáceas, apresenta em sua polpa, pele e sementes quantidades consideráveis de substâncias antioxidantes, tais como compostos fenólicos, vitamina C e carotenoides, além disso contém também em suas sementes amido, cerca de 20%. Assim, este estudo teve como objetivo caracterizar as propriedades físico-químicas, térmicas, reológicas e estruturais, bem como os compostos bioativos, de amido de semente de nêspera (ASN) derivado de arborização urbana e frutos de cultivar comercial em duas fases de maturação: maduro (MA) e imaturo (IM). As micrografias eletrônicas de varredura apresentaram grânulos ASN de forma oval e cilíndrica. Usando padrões de difração de raios-X, foi possível classificar o ASN como uma estrutura cristalina do tipo C. O ASN (MA e IM) apresentou uma maior estabilidade térmica em relação à degradação do que os amidos convencionais nos ensaios termogravimétricos (TG / DTG). Pela calorimetria de varredura diferencial, foi possível sugerir uma correlação entre as temperaturas máximas com as temperaturas de gelatinização obtidas pelo teste de cisalhamento oscilatório do ASN. Os ensaios reológicos revelaram que os géis ASN apresentam comportamento pseudoplástico, com alto grau de tixotropia. Além disso, observou-se maior teor de compostos fenólicos e maior capacidade antioxidante para as amostras de amido de frutos imaturos. Sete compostos bioativos foram quantificados nos amidos por Cromatografia Líquida de Ultra-Alta Eficiência, com grandes concentrações de kaempferol (até 330,46 ?g / kg) e ácido 5-cafeoilquinico (até 135,00 ?g / kg). O ASN mostrou características compatíveis para uso industrial como alternativa aos amidos modificados quimicamente. Palavras-chave: Semente de nêspera, Eriobothrya japônica L., Comportamento reológico, Atividade antioxidante, Análise Térmica.Abstract: Investigating non-conventional starch sources is essential because different chemical compositions, granular sizes, shapes, and amylose and amylopectin ratios, reveal new technological features. The loquat plant, Rosaceae family, presents in its pulp, skin and seeds considerable amounts of antioxidant substances, such as phenolic compounds, vitamin C and carotenoids, and also contains about 20% of its starch seeds. Thus, this study aimed to characterise the physicochemical, thermal, rheological and structural properties, as well as the bioactive compounds, of loquat seed starch (LSS) derived from urban afforestation and commercial fruits at two stages of maturity: ripe (RI) and unripe (UN). Scanning electron micrographs showed oval-and cylindrical-shaped LSS granules. Using X-ray diffraction patterns it was possible to classify the LSS as having a C-type crystalline structure. The LSS (RI and UN) exhibited a higher thermal stability range in relation to degradation than conventional starches in the thermogravimetric assays (TG/DTG). Using differential scanning calorimetry it was possible to suggest a correlation between the peak temperatures with the gelatinisation temperatures obtained by the oscillatory shear test of the LSS. The rheological assays revealed that the LSS gels present pseudoplastic behaviour, with a high degree of thixotropy. Furthermore, higher content of polyphenols and higher antioxidant capacity were observed for the UN starch samples. Seven bioactive compounds were quantified starches by Ultra-High Performance Liquid Chromatography, with major concentrations of kaempferol (up to 330.46 ?g/kg) and 5- caffeoylquinic acid (up to 135.00 ?g/kg). The LSS showed compatible characteristics for industrial usage as an alternative to chemically modified starches. Key-words: Loquat seed, Eriobothrya japônica L., Rheological behavior, Antioxidant activity, Thermal analysis