909 resultados para Ultrasound, Aircraft maintenance


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AbstractObjective:To compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents.Materials and Methods:This prospective, cross-sectional study evaluated 50 adolescents (aged 11–17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard.Results:The obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity).Conclusion:Computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies.

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AbstractThe authors review the main concepts regarding the importance of cleaning/disinfection of ultrasonography probes, aiming a better comprehension by practitioners and thus enabling strategies to establish a safe practice without compromising the quality of the examination and the operator productivity. In the context of biosafety, it is imperative to assume that contact with blood or body fluids represents a potential source of infection. Thus, in order to implement cleaning/disinfection practice, it is necessary to understand the principles of infection control, to consider the cost/benefit ratio of the measures to be implemented, and most importantly, to comprehend that such measures will not only benefit the health professional and the patient, but the society as a whole.

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Screening mammography is the only imaging modality with proved decrease in breast cancer mortality. Ultrasound has been proposed as additional tool for screening. Controversies remain about the real value of sonography in this setting. In Caucasian women with dense breast, sonography improves significantly breast cancer detection, but also increases the false positive cases, biopsies and costs. A careful selection of women who may benefit from additional screening with sonography is mandatory.

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Abstract Objective: To propose an algorithm to determine the necessity for ultrasonography-guided fine-needle aspiration (US-FNA) in preoperative axillary lymph node staging of patients with invasive breast cancer. Materials and Methods: Prospective study developed at National Cancer Institute. The study sample included 100 female patients with breast cancer referred for axillary staging by US-FNA. Results: The overall US-FNA sensitivity was set at 79.4%. The positive predictive value was calculated to be 100%, and the negative predictive value, 69.5%. The US-FNA sensitivity for lymph nodes with normal sonographic features was 0%, while for indeterminate lymph nodes it was 80% and, for suspicious lymph nodes, 90.5%. In the assessment of invasive breast tumors stages T1, T2 and T3, the sensitivity was respectively 69.6%, 83.7% and 100%. US-FNA could avoid sentinel node biopsy in 54% of cases. Conclusion: Axillary ultrasonography should be included in the preoperative staging of all patients with invasive breast cancer. The addition of US-FNA in cases of lymph nodes suspicious for malignancy may prevent more than 50% of sentinel lymphadenectomies, significantly shortening the time interval to definitive therapy.

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Abstract Objective: To estimate the prevalence and evaluate sonographic findings compatible with changes consistent with hepatic steatosis in patients referred for abdominal ultrasonography at four reference centers in Aracaju, SE, Brazil. Materials and Methods: Prospective, descriptive survey, with analytical and quantitative approach, comprising abdominal ultrasonography scans performed with a convex, dynamic 3.75 MHz transducer. Liver dimensions and parenchymal echotexture were evaluated, classifying hepatic steatosis into grades (1, 2 or 3). The SPSS® 22.0 software was used for statistical analysis, adopting p < 0.05 as significance level. Results: A total of 800 individuals (561 women and 239 men) were evaluated. The prevalence of steatosis was 29.1%, and the male patients were most affected, presenting with more advanced grades of disease (p = 0.021), as follows: 119 grade 1 (51.0%); 94 grade 2 (40.4%); and 20 grade 3 (8.6%). The median age patients' was 46 years. Conclusion: In the present study sample, the prevalence of hepatic steatosis was high, particularly in the male patients. Ultrasonography is suggested as a first choice for the diagnosis of this condition, considering its wide availability, low cost and absence of side effects or risks to the patient.

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Introduction : Le bloc transverse de l'abdomen (bloc TAP, Transversus Abdominis Plane) échoguidé consiste en l'injection d'anesthésique local dans la paroi abdominale entre les muscles oblique interne et transverse de l'abdomen sous contrôle échographique. Ceci permet de bloquer l'innervation sensitive de la paroi antérolatérale de l'abdomen afin de soulager la douleur après des interventions chirurgicales. Auparavant, cette procédure reposait sur une technique dite « à l'aveugle » qui utilisait des repères anatomiques de surface. Depuis quelques années, cette technique est effectuée sous guidage échographique ; ainsi, il est possible de visualiser les structures anatomiques, l'aiguille et l'anesthésique local permettant ainsi une injection précise de l'anesthésique local à l'endroit désiré. Les précédentes méta- analyses sur le bloc TAP n'ont inclus qu'un nombre limité d'articles et n'ont pas examiné l'effet analgésique spécifique de la technique échoguidée. L'objectif de cette méta-analyse est donc de définir l'efficacité analgésique propre du bloc TAP échoguidé après des interventions abdominales chez une population adulte. Méthode : Cette méta-analyse a été effectuée selon les recommandations PRISMA. Une recherche a été effectuée dans les bases de donnée MEDLINE, Cochrane Central Register of Controlled Clinical Trials, Excerpta Medica database (EMBASE) et Cumulative Index to Nursing and Allied Health Literature (CINAHL). Le critère de jugement principal est la consommation intraveineuse de morphine cumulée à 6 h postopératoires, analysée selon le type de chirurgie (laparotomie, laparoscopie, césarienne), la technique anesthésique (anesthésie générale, anesthésie spinale avec/ou sans morphine intrathécale), le moment de l'injection (début ou fin de l'intervention), et la présence ou non d'une analgésie multimodale. Les critères de jugement secondaires sont, entre autres, les scores de douleur au repos et à l'effort à 6 h postopératoires (échelle analogique de 0 à 100), la présence ou non de nausées et vomissements postopératoires, la présence ou non de prurit, et le taux de complications de la technique. Résultats : Trente et une études randomisées contrôlées, incluant un total de 1611 adultes ont été incluses. Indépendamment du type de chirurgie, le bloc TAP échoguidé réduit la consommation de morphine à 6 h postopératoires (différence moyenne : 6 mg ; 95%IC : -7, -4 mg ; I =94% ; p<0.00001), sauf si les patients sont au bénéfice d'une anesthésie spinale avec morphine intrathécale. Le degré de réduction de consommation de morphine n'est pas influencé par le moment de l'injection (I2=0% ; p=0.72) ou la présence d'une analgésie multimodale (I2=73% ; p=0.05). Les scores de douleurs au repos et à l'effort à 6h postopératoire sont également réduits (différence moyenne au repos : -10 ; 95%IC : -15, -5 ; I =92% ; p=0.0002; différence moyenne en mouvement : -9 ; 95%IC : -14, -5 ; I2=58% ; p<0. 00001). Aucune différence n'a été retrouvée au niveau des nausées et vomissements postopératoires et du prurit. Deux complications mineures ont été identifiées (1 hématome, 1 réaction anaphylactoïde sur 1028 patients). Conclusions : Le bloc TAP échoguidé procure une analgésie postopératoire mineure et ne présente aucun bénéfice chez les patients ayant reçu de la morphine intrathécale. L'effet analgésique mineure est indépendant du moment de l'injection ou de la présence ou non d'une analgésie multimodale.

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Glioblastoma multiforme (GBM) is the most frequent and lethal primary brain tumor in adults. Accumulating evidence suggests that tumors comprise a hierarchical organization that is, at least partially, not genetically driven. Cells that reside at the apex of this hierarchy are commonly referred to as cancer stem cells (CSCs) and are believed to largely contribute to recurrence and therapeutic failure. Although the complexity of epigenetic regulation of the genome precludes prediction as to which epigenetic changes dominate CSC specification in different cancer types, the ability of microRNAs (miRNAs) to fine-tune expression of entire gene networks places them among prime candidates for establishing CSC properties. In this study we characterized the miRNA expression profile of primary GBM grown either under conditions that enrich for GSCs or their differentiated non-tumorigenic progeny (DGCs). Although, we identified a subset of miRNAs that was strongly differentially expressed between GSCs and DGCs, we observed that in GSCs both let-7 and, paradoxically, their target genes are highly expressed, suggesting protection against let-7 action. Using PAR-CLIP we show that insulin-like growth factor-2 mRNA-binding protein 2 (IMP2) provides a mechanism for let-7 target gene protection that represents an alternative to LIN28A/B, which abrogates let-7 biogenesis in normal embryonic and certain malignant stem cells. By direct binding to miRNA recognition elements, IMP2 protects its targets from let-7 mediated decay. Importantly, depletion of IMP2 in GSCs strongly impairs their self- renewal properties and tumorigenicity in vivo, a phenotype that can be rescued by expression of LIN28B, suggesting that IMP2 mainly contributes to GSC maintenance by protecting let-7 target genes from silencing. Using mouse models, we show that depletion of IMP2 in neural stem cells (NSCs) induces let-7 target gene down-regulation, impairs their clonogenic capacity, and affects differentiation. Taken together, our observations describe a novel regulatory function of IMP2 in the let-7 axis whereby it supports GSC and NSC specification. Résumé (Français) Le glioblastome (GBM) est la tumeur primaire maligne du cerveau la plus fréquente. De nombreuses études ont démontré l'existence d'une organisation hiérarchique des cellules cancéreuses liée à des mécanismes épigénétiques. Les cellules qui se trouvent au sommet de cette hiérarchie sont appelées cellules souches cancéreuses (CSC), et contribuent à l'échec thérapeutique. Bien que la complexité des régulateurs épigénétiques permette difficilement de prédire quel mécanisme contribue le plus aux propriétés des CSC, la capacité des microRNAs (miRNAs) de réguler des réseaux entiers de gènes, les placent comme des candidats de premiers choix. Ici, nous avons caractérisé le profil d'expression des miRNAs dans des tumeurs primaires de GBM cultivées dans des conditions qui enrichissent soit pour les CSC, soit pour leur contrepartie de cellules cancéreuses différences (CCD). De manière surprenante et paradoxale la famille de miRNA let-7 et leurs gènes cibles étaient hautement exprimés dans les CSC, suggérant un mécanisme de protection contre l'action des let-7. Avec l'aide de la technologie PAR-CLIP, nous démontrons que la protéine IMP2, protège les mRNAs de l'action des let-7 et représente une alternative à Lin28A/B, qui d'ordinaire réprime fortement la maturation des let-7 dans les cellules souches embryonnaires et divers cancers. En se liant à la région ciblée par les let-7, IMP2 protège ses transcrits de l'action de cette classe de microRNA qui est tumoro-supressive. La déplétion d'IMP2 dans des CSC de GBM réduit fortement leur clonogénicité in vitro et leur tumorigénicité in vivo. Ceci peut être reversé en introduisant Lin28B dans des CSC de GBM, suggérant qu'IMP2 exerce ses fonctions pro-tumorigéniques en modulant l'axe let-7. Avec l'aide de modèles murins, nous observons que la déplétion de IMP2 dans les cellules souches neurales (CSN) induit une baisse de leur clonogénicité et des cibles des miRNAs let-7, suggérant une conservation de ce mécanisme entre les CSC de GBM et les CSN. En résumé, nos observations définissent une nouvelle fonction de IMP2 dans l'axe let-7 par lequel il contribue au maintien des propriétés des CSC et des CSN.

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The target of this thesis is to find out potential of automation maintenance services in Russian industry, especially in the region of St. Petersburg. At the beginning of this study the industrial maintainability and process efficiency are discussed from the point of view of process automation. A survey of the present technology and maintenance methods has been made during five visits to local plants. The results of the interviews are analyzed numerically to clarify the common needs and the potential of automation maintenance services. The most interesting services are evaluated by their required resources to find economically justified solutions for the needs of the industry. As results of this study, some service products that would interest interviewed companies have been introduced. These could be offered to the industry to enhance cost-efficiency and productivity of processes.

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BACKGROUND: Hospitalization is a costly and distressing event associated with relapse during schizophrenia treatment. No information is available on the predictors of psychiatric hospitalization during maintenance treatment with olanzapine long-acting injection (olanzapine-LAI) or how the risk of hospitalization differs between olanzapine-LAI and oral olanzapine. This study aimed to identify the predictors of psychiatric hospitalization during maintenance treatment with olanzapine-LAI and assessed four parameters: hospitalization prevalence, incidence rate, duration, and the time to first hospitalization. Olanzapine-LAI was also compared with a sub-therapeutic dose of olanzapine-LAI and with oral olanzapine. METHODS: This was a post hoc exploratory analysis of data from a randomized, double-blind study comparing the safety and efficacy of olanzapine-LAI (pooled active depot groups: 405 mg/4 weeks, 300 mg/2 weeks, and 150 mg/2 weeks) with oral olanzapine and sub-therapeutic olanzapine-LAI (45 mg/4 weeks) during 6 months' maintenance treatment of clinically stable schizophrenia outpatients (n=1064). The four psychiatric hospitalization parameters were analyzed for each treatment group. Within the olanzapine-LAI group, patients with and without hospitalization were compared on baseline characteristics. Logistic regression and Cox's proportional hazards models were used to identify the best predictors of hospitalization. Comparisons between the treatment groups employed descriptive statistics, the Kaplan-Meier estimator and Cox's proportional hazards models. RESULTS: Psychiatric hospitalization was best predicted by suicide threats in the 12 months before baseline and by prior hospitalization. Compared with sub-therapeutic olanzapine-LAI, olanzapine-LAI was associated with a significantly lower hospitalization rate (5.2% versus 11.1%, p < 0.01), a lower mean number of hospitalizations (0.1 versus 0.2, p = 0.01), a shorter mean duration of hospitalization (1.5 days versus 2.9 days, p < 0.01), and a similar median time to first hospitalization (35 versus 60 days, p = 0.48). Olanzapine-LAI did not differ significantly from oral olanzapine on the studied hospitalization parameters. CONCLUSIONS: In clinically stable schizophrenia outpatients receiving olanzapine-LAI maintenance treatment, psychiatric hospitalization was best predicted by a history of suicide threats and prior psychiatric hospitalization. Olanzapine-LAI was associated with a significantly lower incidence of psychiatric hospitalization and shorter duration of hospitalization compared with sub-therapeutic olanzapine-LAI. Olanzapine-LAI did not differ significantly from oral olanzapine on hospitalization parameters.

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Background: Effective treatment for breast cancer requires accurate preoperative planning, developing and implementing a consistent definition of margin clearance, and using tools that provide detailed real-time intraoperative information on margin status. Intraoperative ultrasound (IOUS) may fulfil these requirements and may offer few advantages that other preoperative localization and intraoperative margin assessment techniques may notPurpose: The goal of the present work is to determine how accurate the intraoperative ultrasound should be to acquire complete surgical excision with negative histological margins in patients undergoing Breast Conservative SurgeryDesign: A diagnostic test study with a cross-sectional design carried out in a tertiary referral hospital in Girona within a Breast Pathology UnitParticipants: Women diagnosed with breast cancer undergoing a Breast Conservative Surgery in the Breast Pathology Unit at Hospital Universitari de Girona Dr. Josep Trueta

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Security issues in telecommunication networks have become more important due to the development of the industry. The number of network elements and services has increased in the radio network as in the core network side, which has increased the number of security related issues. Ericsson has developed an OSS-RC product for operation and maintenance porpoises into the telecommunication networks. OSS-RC is used in a number of telecommunications operators, which have Ericsson's products used in their telecommunication networks. Ericsson provides product installation and maintenance support and guidance, but despite this, the product may have security related issues, either due to lack of following the instructions, human error or defect in the product itself or in a third party products attached. Ericsson’s Operation and Maintenance Security Service for OSS-RC networks aims to provide tools for checking the security level of the O&M product so that it meets all requirements and Ericsson’s own security related rules. Each customer has a unique telecommunications network structure and services, and so the security service has to be to create individually depending on the customer. The purpose of this thesis is to define the basic instructions for creating the security service for different customers.

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There are several filtration applications in the pulp and paper industry where the capacity and cost-effectiveness of processes are of importance. Ultrafiltration is used to clean process water. Ultrafiltration is a membrane process that separates a certain component or compound from a liquid stream. The pressure difference across the membrane sieves macromolecules smaller than 0.001-0.02 μm through the membrane. When optimizing the filtration process capacity, online information about the conditions of the membrane is needed. Fouling and compaction of the membrane both affect the capacity of the filtration process. In fouling a “cake” layer starts to build on the surface of the membrane. This layer blocks the molecules from sieving through the membrane thereby decreasing the yield of the process. In compaction of the membrane the structure is flattened out because of the high pressure applied. The higher pressure increases the capacity but may damage the structure of the membrane permanently. Information about the compaction is needed to effectively operate the filters. The objective of this study was to develop an accurate system for online monitoring of the condition of the membrane using ultrasound reflectometry. Measurements of ultrafiltration membrane compaction were made successfully utilizing ultrasound. The results were confirmed by permeate flux decline, measurements of compaction with a micrometer, mechanical compaction using a hydraulic piston and a scanning electron microscope (SEM). The scientific contribution of this thesis is to introduce a secondary ultrasound transducer to determine the speed of sound in the fluid used. The speed of sound is highly dependent on the temperature and pressure used in the filters. When the exact speed of sound is obtained by the reference transducer, the effect of temperature and pressure is eliminated. This speed is then used to calculate the distances with a higher accuracy. As the accuracy or the resolution of the ultrasound measurement is increased, the method can be applied to a higher amount of applications especially for processes where fouling layers are thinner because of smaller macromolecules. With the help of the transducer, membrane compaction of 13 μm was measured in the pressure of 5 bars. The results were verified with the permeate flux decline, which indicated that compaction had taken place. The measurements of compaction with a micrometer showed compaction of 23–26 μm. The results are in the same range and confirm the compaction. Mechanical compaction measurements were made using a hydraulic piston, and the result was the same 13 μm as obtained by applying the ultrasound time domain reflectometry (UTDR). A scanning electron microscope (SEM) was used to study the structure of the samples before and after the compaction.