<p>This study was undertaken to investigate the involutional changes of the uterus and uterine cavity by ultrasound (US), gray-scale and Doppler, after normal delivery, and to compare with the corresponding findings from women with puerperal complications, particularly retained placental tissue (RPT). The overall design was exploratory and prospective, with the use of descriptive statistics for analysis. </p><p>Forty-two women with uncomplicated vaginal term delivery were examined on post-partum days 1, 3, 7, 14, 28 and 56. The AP diameters of the uterus and uterine cavity and morphological findings were recorded. The maximum AP diameters of the uterus and uterine cavity diminished from 92.0 mm on day 1 to 38.9 mm at day 56 and from 15.8 mm at day 1 to 4.0 mm at day 56, respectively. The uterus was most often empty in the early and late puerperium while a mixed echo pattern over the whole cavity was found during mid puerperium (I).</p><p>Seventy-nine women with secondary post partum hemorrhage (SPH) were examined on the day they presented with clinical symptoms. US revealed an echogenic mass in the uterine cavity in 17 of 18 patients treated surgically and histology confirmed placental tissue in 14 of these. Sixty-one patients with either an empty cavity or mixed echo pattern had an uneventful puerperal course after conservative treatment (II).</p><p>AP diameters and morphological findings for 55 women with endometritis, 28 after caesarean section and 20 after manual evacuation of the placenta overlapped extensively with normal references (III).</p><p>The physiological vascular involution studied in 45 women after normal delivery showed that PI and RI indices did not change significantly until day 28 postpartum. The presence of at least one uterine artery notch was found in 13.3% of the women at day 1 and in 90.6% at day 56 postpartum (IV).</p><p>PI and RI values were measured and compared with reference values in 20 women with clinical suspicion of RPT who were to undergo surgical evacuation. Mean resistance indices were below the 10th percentile for eight of these 20 women, but overlapping was considerable. Doppler US has limited value as a diagnostic tool for RPT. The absence of a hyper-vascular area in the myometrium does not exclude RPT but an echogenic mass in the cavity is a sign of RPT (V).</p>

For ecological reasons, the current main challenge of the automotive industry is to reduce the fuel consumption of vehicles and then emissions of greenhouse gas. In this context, steelmakers and automotive manufacturers decided for some years now to join their efforts to promote the development and use of advanced high strength steels such as TRIP steels. A combination of high strength and large elongation is obtained thanks to the TRansformation Induced Plasticity (TRIP) effect. However, improvement of the mechanical properties is still possible, especially by the refinement of the matrix. In this work, two main ways were followed in order to reach improved properties. The classical way consisting of the annealing of cold-rolled samples and an innovative way consisting of obtaining the desired microstructure by direct hot rolling of the samples. In the classical way, this refinement can be obtained by acting on the chemical composition (with such alloying elements like Cu and Nb). It was observed that complete recrystallisation of the ferrite matrix is quite impossible in presence of Cu precipitates. In addition, if the ferrite recrystallisation is not completed before reaching the eutectoid temperature, the recrystallisation will be slowed down by a large way. An innovative heat treatment consisting in keeping the copper in solid solution in the high-Cu steel was developed. Therefore, ferrite recrystallises quite easily and very fine ferrite grains (~1µm) were obtained. In the innovative way, the effects of hot-rolling conditions on TRIP-assisted multiphase steels are of major importance for industrial practice and could open new dimensions for the TRIP steels (i.e. thanks to precipitation mechanisms leading to additive strengthening). Impressive mechanical properties (true stress at maximum load of 1500 MPa and true strain at uniform elongation of 0.22) were obtained with a relatively easy thermomechanical process, the role played by Nb being essential.

This study was undertaken to investigate the involutional changes of the uterus and uterine cavity by ultrasound (US), gray-scale and Doppler, after normal delivery, and to compare with the corresponding findings from women with puerperal complications, particularly retained placental tissue (RPT). The overall design was exploratory and prospective, with the use of descriptive statistics for analysis. Forty-two women with uncomplicated vaginal term delivery were examined on post-partum days 1, 3, 7, 14, 28 and 56. The AP diameters of the uterus and uterine cavity and morphological findings were recorded. The maximum AP diameters of the uterus and uterine cavity diminished from 92.0 mm on day 1 to 38.9 mm at day 56 and from 15.8 mm at day 1 to 4.0 mm at day 56, respectively. The uterus was most often empty in the early and late puerperium while a mixed echo pattern over the whole cavity was found during mid puerperium (I). Seventy-nine women with secondary post partum hemorrhage (SPH) were examined on the day they presented with clinical symptoms. US revealed an echogenic mass in the uterine cavity in 17 of 18 patients treated surgically and histology confirmed placental tissue in 14 of these. Sixty-one patients with either an empty cavity or mixed echo pattern had an uneventful puerperal course after conservative treatment (II). AP diameters and morphological findings for 55 women with endometritis, 28 after caesarean section and 20 after manual evacuation of the placenta overlapped extensively with normal references (III). The physiological vascular involution studied in 45 women after normal delivery showed that PI and RI indices did not change significantly until day 28 postpartum. The presence of at least one uterine artery notch was found in 13.3% of the women at day 1 and in 90.6% at day 56 postpartum (IV). PI and RI values were measured and compared with reference values in 20 women with clinical suspicion of RPT who were to undergo surgical evacuation. Mean resistance indices were below the 10th percentile for eight of these 20 women, but overlapping was considerable. Doppler US has limited value as a diagnostic tool for RPT. The absence of a hyper-vascular area in the myometrium does not exclude RPT but an echogenic mass in the cavity is a sign of RPT (V).

No description available.

X-ray diffraction (XRD) profile fitting (Rietveld method) was used in this study to characterize the microstructure for seven microalloyed steels, which were produced through thermomechanical controlled processing (TMCP). Microstructure characterization was conducted through the strip thickness. The microstructural variables studied include subgrain size, dislocation density, texture index and weight percent of retained austenite. The subgrain size was also analyzed by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The effects of processing parameters, including coiling temperature, cooling rate and alloying elements, on the microstructure were also investigated. It was found that decreasing the coiling temperature resulted in a finer subgrain size and higher dislocation densities. The texture index was observed to increase with decreasing coiling temperature. The subgrain size decreased and dislocation density increased as the amount of alloying elements (Ni, Mo and Mn) were increased. The amount of retained austenite increased at the strip center with increasing coiling temperature and increasing C and Ni content. / Materials Engineering

O afrouxamento dos parafusos protéticos é descrito na literatura como uma das complicações mais frequentes das próteses sobre implantes. Durante sua confecção, os profissionais sentem necessidade de remover várias vezes as próteses e/ou componentes protéticos, soltando e re-apertando os parafusos repetidamente. O principal objetivo deste trabalho foi avaliar a variação do torque de remoção de parafusos de fixação de pilares protéticos a implantes osteointegráveis após sucessivos ciclos de parafusamento e desparafusamento. Outro objetivo foi avaliar a influência do hexágono da base do pilar no torque de remoção dos parafusos. Para isso, foram utilizados 20 implantes de plataforma regular com hexágono externo e 20 pilares protéticos sextavados, que foram parafusados aos implantes com um parafuso de titânio, aplicando-se a este um torque de 32Ncm, por meio de um torquímetro digital. Os conjuntos implante/pilar/parafuso foram divididos em dois grupos: (1) pilares cujo hexágono da base foram removidos e (2) pilares convencionais, com hexágono na base. Cada conjunto recebeu uma restauração provisória e foi submetido a ciclagem mecânica por 15 minutos. Depois, os parafusos foram removidos, medindo-se o torque de remoção. Esta sequência foi repetida dez vezes e então o parafuso foi trocado por outro sem uso, e mais um ciclo foi realizado. Uma análise de regressão linear demonstrou nos dois grupos uma queda do torque de remoção do parafuso ao longo dos repetidos ciclos de inserção/remoção. A comparação entre os coeficientes da regressão nos dois grupos não revelou diferença entre eles. Também não houve diferença entre as médias das 5 últimas repetições e o 11 ciclo, com o parafuso novo. Concluiu-se que (1) repetidos parafusamentos e desparafusamentos promoveram a diminuição progressiva do torque de remoção dos parafusos, (2) a troca do parafuso por outro sem uso após dez ciclos de inserção/remoção não aumentou sua resistência ao afrouxamento, e (3) a remoção do hexágono da base do pilar protético não exerceu nenhum efeito sobre o torque de remoção do parafuso. / Screw loosening is one of the most common problems of implant-retained prostheses. During their confection, dentists need to remove and re-install them several times, loosening and re-tightening the screws repeatedly. The first purpose of this study was to evaluate the effects of repeated insertion/removal cycles on the removal torque of retaining prosthetic screws. The second purpose was to evaluate the influence of the hexagon of the abutment on the removal torque. For that, 20 regular external hex implants were used and 20 hexagonal abutments were tightened to the implants with a titanium alloy screw, with an insertion torque of 32Ncm, given by a digital torque gauge. The implant/abutment/screw assemblies were divided into two groups: (1) abutments with no hexagon on the base and (2) abutments with an hexagon on the base. Each assembly received a provisional restoration and was submitted to mechanical loading cycles for 15 minutes. After this, the screws were removed and the removal torque measured. This sequence was repeated ten times and then, the screw was changed for a new one, and another cycle was done. Linear regression analysis was performed and showed that removal torque values tended to decrease as the number of insertion/removal cycles increased, for both groups. Comparisons of the slopes and the intercepts between the two groups showed no statistic difference between them. There was also no difference between the mean values of last 5 cycles and the 11th cycle. It was concluded that (1) repeated insertion/removal cycles promoted gradual reduction in removal torque of screws, (2) changing screw by a new one after ten insertion/removal cycles did not increase resistance to loosening, and (3) removal of the hexagon of the abutment base had no effect on the removal torque of the screw.

O estudo teve como objetivos analisar as evidências disponíveis na literatura sobre o processo de contagem cirúrgica (compressas, instrumentos cirúrgicos e perfurocortantes) e analisar como ocorre o processo de contagem cirúrgica, segundo a opinião dos enfermeiros que atuam em unidades de centro cirúrgico de hospitais de uma cidade localizada no interior do Estado de São Paulo. Para alcançar os objetivos propostos, a pesquisa foi conduzida em duas fases: a elaboração de revisão integrativa e a condução de estudo descritivo. A busca dos estudos primários para inclusão na revisão integrativa foi realizada nas bases de dados PubMed, CINAHL e LILACS. A amostra da revisão integrativa foi composta de 28 estudos primários, agrupados em três categorias: fatores de risco para retenção de itens cirúrgicos, processo de contagem cirúrgica e uso de tecnologias para o aprimoramento do processo de contagem cirúrgica. A elaboração da revisão integrativa possibilitou a síntese de evidências sobre o processo de contagem cirúrgica, na qual foi possível detectar os fatores de risco para retenção de itens cirúrgicos, como o processo de contagem cirúrgica deve ser realizado, bem como por quem e quando; além do conhecimento das tecnologias adjuntas que podem aprimorar o processo de contagem manual. O estudo descritivo foi conduzido em 16 unidades de centro cirúrgico, com a participação de 55 enfermeiros que atuavam diretamente neste setor dos hospitais selecionados. Para a coleta de dados, foi elaborado instrumento submetido à validação aparente e de conteúdo por cinco juízes. Os participantes do estudo responderam a questões sobre o processo de contagem cirúrgica (compressas, instrumentos cirúrgicos e perfurocortantes): como era realizado, por quem e quando. Quando o enfermeiro indicou que, no serviço de saúde, não era executada a contagem de algum dos itens cirúrgicos investigados, solicitou-se a sua opinião de como deveria ser realizado determinado processo. Assim, 52 (94,5%) participantes responderam que o processo de contagem cirúrgica era realizado no seu local de trabalho e três (5,5%) não. A contagem de instrumentos cirúrgicos era realizada, de acordo com 55,8% dos enfermeiros (n=29); 88,5% (n=46) dos participantes afirmaram que o processo de contagem de compressas era executado e 48,1% (n=25) dos enfermeiros informaram a realização do processo de contagem de perfurocortantes. A Organização Mundial de Saúde preconiza como item para a segurança do paciente que o processo de contagem cirúrgica seja realizado em qualquer cirurgia, e o enfermeiro perioperatório tem papel fundamental neste processo e na prevenção de retenção de itens cirúrgicos. Esse profissional deve implementar protocolos de execução desse processo pautados em evidências recentes, na unidade de centro cirúrgico. Entretanto, para o processo de contagem cirúrgica ocorrer efetivamente na prática clínica, há necessidade de recursos humanos treinados e de dispositivos que auxiliem na contagem, como lousa na sala de operação, recipientes exclusivos para colocação de compressas e perfurocortantes, além do uso adequado de tecnologias como raios-X, compressas com código de barras e compressas com marcadores de radiofrequência. Assim, a instituição de saúde deve dar o suporte necessário para a adequada realização do processo de contagem cirúrgica / The aims of this study were to analyze the evidence of surgical count process (sponges, surgical instruments and sharps) available in literature and examine how the surgical count process takes place, according to the opinion of nurses working in surgical units of hospitals of a city in upstate São Paulo. The study was conducted in two phases: an integrative review and a descriptive study. The search for primary studies to be included in the integrative review was conducted in PubMed, CINAHL and LILACS databases. The integrative review sample consisted of 28 primary studies, grouped into three categories: risk factors for retained surgical items, surgical count process and using technologies to improve the surgical count. The integrative review allowed synthesizing the evidence on the surgical count process, which enabled to detect the risk factors for retained surgical items, how the process should be performed, as well as who should perform it and when; in addition to the identifying the knowledge of supporting technologies that could improve the manual counting process. The descriptive study was performed in 16 surgical units, counting with the participation of 55 nurses working directly in the referred unit of the selected hospitals. Data collection was performed using an instrument previously submitted to apparent and content validation by five judges. The participants answered questions regarding the surgical count process (sponges, surgical instruments and sharps): who performed it, how and when. Whenever nurses indicated that, at their health service, there were flaws in counting any of the investigated surgical items, they were asked about their opinion as to how the process should be performed. Fifty-two (94.5%) participants answered that the surgical count process was performed at their workplace whereas three (5.5%) stated it was not. According to 55.8% of nurses (n=29) surgical instruments were counted; 88.5% (n=46) of participant reported that the sponges count process was performed, and 48.1% (n=25) informed that sharps were counted. The World Health Organization recommends the surgical count process as a patient safety item, and that it should be performed in every surgery, with the perioperative nurse playing a key role in this process as well as in avoiding the retained surgical items. Nurses should implement protocols for performing this procedure in the surgical unit, supported by recent evidence. Nevertheless, to ensure the surgical count process is effective, the staff must be properly trained and specific devices to assist the counting procedure must be made available, such as keeping whiteboards operating room, as well as exclusive containers for placing sponges and sharps, in addition to an appropriate utilization of supporting technologies such as X- rays, bar-coded sponges and radio frequency tagged sponges. Thus, health institutions should provide the necessary support for an effective surgical count process

Seit vielen Jahren wächst die Nachfrage bezüglich sparsamer Fahrzeuge; die Autohersteller konkurrieren miteinander und werben mit neuen Fahrzeugkonzepten, in denen hochmoderne Werkstoffe ihre Anwendung finden. In dieser Arbeit werden Legierungskonzepte und entsprechende Warmwalztechnologien einer ultrahochfesten bainitischen Stahlsorte mit Restaustenit vorgestellt, die der genannten Anwendung angepasst werden können. Der gewählte Werkstoff gehört zu den Stählen mit mittleren Kohlenstoffgehalten, die sich nach der - im Rahmen dieser Arbeit entwickelten - Behandlung durch hohe Zugfestigkeit bei vergleichsweise hoher Bruchdehnung auszeichnen. Es werden erweiterte Modelle zur Beschreibung der Phasenumwandlung von Stählen im Bainitgebiet vorgestellt. Die Ergebnisse aus den Experimenten wurden genutzt, um die Modelle zu ergänzen und zu evaluieren. Dabei wird nicht nur der Warmwalzprozess, sondern auch die chemische Zusammensetzung der Stähle selbst optimiert. Die hier präsentierte Arbeit erstreckt sich über die gesamte Produktionskette und zeigt geeignete Herstellungsbedingungen, die in Betriebsanlagen leicht realisierbar sind und umgesetzt wurden.

The effect of the chemical composition, austenitisation temperature and tempering temperature and time on the mechanical properties and on the ballistic performance of martensitic steel armour plates was studied. It was established in this study that the mechanical properties and the ballistic performance of martensitic steels can be optimised by controlling the chemical composition and the heat treatment parameters. However, it was observed that for a given chemical composition of the steel the heat treatment parameters to be applied to advanced ballistic performance armour plates were different from those required for higher mechanical properties. Such a contradiction rendered the relationship between mechanical properties and ballistic performance questionable. Systematic analysis of the microstructure and the fracture mechanism of some martensitic armour plate steels was carried out to explain the improved ballistic performance of steels whose mechanical properties were below that specificied for military and security applications. It was inferred from phase analysis and its quantification by X-ray diffraction, characterisation of the martensite using scanning electron microscopy, transmission electron microscopy and atomic force microscopy that the retained austenite located in the plate interfaces and on grain boundaries of the martensite was the main constituent resisting localised yielding during ballistic impact on thin steel plates. A part of the kinetic energy is transformed into adiabatic heat where a reaustenitisation of the plate martensite and the formation of new lath martensite was observed. Another part is used to elastically and plastically deform the ballistic impact affected region around the incidence point. Dislocation pile-ups at twinned plate interfaces suggest that the twin interfaces act as barriers to dislocation movement upon high velocity impact loading. The diameter of the affected regions, that determines the volume of the material deforming plastically upon impact, was found to vary as a function of the volume fraction of retained austenite in the martensitic steel. Upon impact, retained austenite transforms to martensite by Transformation Induced Plasticity, the “ TRIP ” effect. High volume fractions of retained austenite in the martensitic steel were found to yield low values of the ratio yield strength to ultimate tensile strength (YS/UTS) and a high resistance against localised yielding and, therefore, against ballistic perforation. A Ballistic Parameter was proposed for the prediction of ballistic performance using the volume fraction of retained austenite and the thickness of the armour plate as variables. Based on the martensite structure and the results of the ballistic testing of 13 armour plate steels a design methodology comprising new specifications was proposed for the manufacture of armour plates whose thicknesses may be thinner than 6mm. / Dissertation (MSc (Metallurgical Engineering))--University of Pretoria, 2007. / Materials Science and Metallurgical Engineering / unrestricted

A austenita retida está sempre presente na microestrutura de camada cementada de aços, em maior ou menor quantidade. Como é uma fase dúctil comparada à martensita, sua presença tem sido alvo de muita controvérsia. Este trabalho apresenta um estudo sobre a influência da austenita retida na propagação de trincas curtas por fadiga em camada cementada de aço SAE 8620. Foram feitos ensaios de fadiga por flexão em quatro pontos, a temperatura ambiente, em corpos de prova sem entalhe com três níveis de amplitude de tensão e razão de tensões de 0,1. Através de diferentes ciclos de cementação e tratamentos térmicos, foram obtidas camadas cementadas com quatro níveis de austenita retida na microestrutura. O teor de austenita retida foi medido através da técnica de difração de Raios-X. Trincas superficiais foram monitoradas por meio da técnica de réplicas de acetato. Como resultados foram obtidos tamanho de trinca em função do número de ciclos e taxa de crescimento de trincas curtas. Corpos de prova com maiores níveis de austenita retida apresentaram maior vida em fadiga. / The retained austenite is always present in case carburized steel microstructure in small or high percentages. Since it is a ductile phase, its presence has long been a controversial subject. The influence of retained austenite on short fatigue crack propagation in case carburized SAE 8620 steel was studied in this work. Four-point-bend fatigue tests were carried out at room temperature in specimens without notch using three levels of stress range and a stress ratio of 0.1. Four different amount of retained austenite in the case carburized microstructure were obtained through different cycles of carburizing and heat treating. The retained austenite content was measured by X-ray technique, and the surface short crack growth was monitored by means of acetate replication technique. Crack length versus number of cycles and crack growth rate versus mean crack length were obtained as results. Specimens with higher levels of retained austenite in the carburized case showed longer fatigue life.