962 resultados para Digital to Analog Converter
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OBJECTIVE: To evaluate the clinical performance of glass-ceramic/zirconia crowns fabricated using intraoral digital impressions - a retrospective study with a three-year follow-up. METHODS: 70 consecutive patients with a total of 86 glass-ceramic/zirconia crowns were treated by a single clinician using standardized clinical and laboratory protocols. A complete digital workflow was adopted for the purpose except for the veneering procedure for the glass-ceramic crowns. Occlusal adjustments were made before the ceramic glazing procedure. Before cementation, all abutments where carefully cleaned with a 70% alcoholic solution and air dried. Cementation was performed using dual-curing, self-adhesive resin cement. Patients were re-examined after 12, 24 and 36 months, to assess crown chipping/fractures. RESULTS: After the three-year follow-up, none of the zirconia-based restoration was lost ("apparent" survival rate 100%) otherwise, the chipping rate of the veneering material increased from 9.3% after 12 months, to 14% after 24 months to 30.2% after 36 months. As a consequence, the "real" success rate after 3 years was 69.8%. CONCLUSIONS: After 3 years the success rate of zirconia-based crowns was 69.8%, while the incidence of the chipping was 30.2%. Assuming an exponential increase in chipping rate between 12 and 36 months it can be argued that, among others, the fatigue-mechanism could be advocated as the main factor for the failure of glass-ceramic veneered zirconia especially after 24 months.
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The determination of line crossing sequences between rollerball pens and laser printers presents difficulties that may not be overcome using traditional techniques. This research aimed to study the potential of digital microscopy and 3-D laser profilometry to determine line crossing sequences between a toner and an aqueous ink line. Different paper types, rollerball pens, and writing pressure were tested. Correct opinions of the sequence were given for all case scenarios, using both techniques. When the toner was printed before the ink, a light reflection was observed in all crossing specimens, while this was never observed in the other sequence types. The 3-D laser profilometry, more time-consuming, presented the main advantage of providing quantitative results. The findings confirm the potential of the 3-D laser profilometry and demonstrate the efficiency of digital microscopy as a new technique for determining the sequence of line crossings involving rollerball pen ink and toner. With the mass marketing of laser printers and the popularity of rollerball pens, the determination of line crossing sequences between such instruments is encountered by forensic document examiners. This type of crossing presents difficulties with optical microscopic line crossing techniques involving ballpoint pens or gel pens and toner (1-4). Indeed, the rollerball's aqueous ink penetrates through the toner and is absorbed by the fibers of the paper, leaving the examiner with the impression that the toner is above the ink even when it is not (5). Novotny and Westwood (3) investigated the possibility of determining aqueous ink and toner crossing sequences by microscopic observation of the intersection before and after toner removal. A major disadvantage of their study resides in destruction of the sample by scraping off the toner line to see what was underneath. The aim of this research was to investigate the ways to overcome these difficulties through digital microscopy and three-dimensional (3-D) laser profilometry. The former was used as a technique for the determination of sequences between gel pen and toner printing strokes, but provided less conclusive results than that of an optical stereomicroscope (4). 3-D laser profilometry, which allows one to observe and measure the topography of a surface, has been the subject of a number of recent studies in this area. Berx and De Kinder (6) and Schirripa Spagnolo (7,8) have tested the application of laser profilometry to determine the sequence of intersections of several lines. The results obtained in these studies overcome disadvantages of other methods applied in this area, such as scanning electron microscope or the atomic force microscope. The main advantages of 3-D laser profilometry include the ease of implementation of the technique and its nondestructive nature, which does not require sample preparation (8-10). Moreover, the technique is reproducible and presents a high degree of freedom in the vertical axes (up to 1000 μm). However, when the paper surface presents a given roughness, if the pen impressions alter the paper with a depth similar to the roughness of medium, the results are not always conclusive (8). It becomes difficult in this case to distinguish which characteristics can be imputed to the pen impressions or the quality of the paper surface. This important limitation is assessed by testing different types of paper of variable quality (of different grammage and finishing) and the writing pressure. The authors will therefore assess the limits of 3-D laser profilometry technique and determine whether the method can overcome such constraints. Second, the authors will investigate the use of digital microscopy because it presents a number of advantages: it is efficient, user-friendly, and provides an objective evaluation and interpretation.
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An automatic system was designed to concurrently measure stage and discharge for the purpose of developing stage-discharge ratings and high flow hydrographs on small streams. Stage, or gage height, is recorded by an analog-to-digital recorder and discharge is determined by the constant-rate tracer-dilution method. The system measures flow above a base stage set by the user. To test the effectiveness of the system and its components, eight systems, with a variety of equipment, were installed at crest-stage gaging stations across Iowa. A fluorescent dye, rhodamine-WT, was used as the tracer. Tracer-dilution discharge measurements were made during 14 flow periods at six stations from 1986 through 1988 water years. Ratings were developed at three stations with the aid of these measurements. A loop rating was identified at one station during rapidly-changing flow conditions. Incomplete mixing and dye loss to sediment apparently were problems at some stations. Stage hydrographs were recorded for 38 flows at seven stations. Limited data on background fluorescence during high flows were also obtained.
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Glucagon-like peptide-1(7-37) (GLP-1) is the most potent insulinotropic hormone characterized thus far. Because its activity is preserved in non-insulin-dependent diabetes mellitus (NIDDM) patients, it is considered a potential new drug for the treatment of this disease. One limitation in its therapeutic use is a short half-life in vivo (5 minutes), due in part to a fast degradation by the endoprotease dipeptidylpeptidase IV (DPPIV). Recently, it was reported that GLP-1 became resistant to DPPIV when the alanine residue at position 8 was replaced by a glycine (GLP-1-Gly8). We report here that this change slightly decreased the affinity of the peptide for its receptor (IC50, 0.41 +/- 0.14 and 1.39 +/- 0.61 nmol/L for GLP-1 and GLP-1-Gly8, respectively) but did not change the efficiency to stimulate accumulation of intracellular cyclic adenosine monophosphate (cAMP) (EC50, 0.25 +/- 0.05 and 0.36 +/- 0.06 nmol/L for GLP-1 and GLP-1-Gly8, respectively). Second, we demonstrate for the first time that this mutant has an improved insulinotropic activity compared with the wild-type peptide when tested in vivo in an animal model of diabetes. A single injection of 0.1 nmol GLP-1-Gly8 in diabetic mice fed a high-fat diet can correct fasting hyperglycemia and glucose intolerance for several hours, whereas the activity of 1 nmol GLP-1 vanishes a few minutes after injection. These actions were correlated with increased insulin and decreased glucagon levels. Interestingly, normoglycemia was maintained over a period that was longer than the predicted peptide half-life, suggesting a yet undescribed long-term effect of GLP-1-Gly8. GLP-1-Gly8 thus has a markedly improved therapeutic potential compared with GLP-1, since it can be used at much lower doses and with a more flexible schedule of administration.
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Abstract We introduce a label-free technology based on digital holographic microscopy (DHM) with applicability for screening by imaging, and we demonstrate its capability for cytotoxicity assessment using mammalian living cells. For this first high content screening compatible application, we automatized a digital holographic microscope for image acquisition of cells using commercially available 96-well plates. Data generated through both label-free DHM imaging and fluorescence-based methods were in good agreement for cell viability identification and a Z'-factor close to 0.9 was determined, validating the robustness of DHM assay for phenotypic screening. Further, an excellent correlation was obtained between experimental cytotoxicity dose-response curves and known IC values for different toxic compounds. For comparable results, DHM has the major advantages of being label free and close to an order of magnitude faster than automated standard fluorescence microscopy.
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Resumen: El artículo analiza los problemas de accesibilidad que actualmente presentan los artículos científicos en soporte digital. El estudio se centra en los aspectos de facilidad de uso del contenido de los documentos digitales según la forma en que se publiquen, sin entrar en el estudio de los distintos sistemas de recuperación. Se analizan los dos formatos más utilizados para la publicación de artículos científicos en soporte digital: HTML y PDF, estudiando el desempeño lector en relación a la presencia de sumarios o de tablas internas o vinculadas. El estudio se ha realizado con dos colectivos: 30 sujetos ciegos, usuarios de Jaws, contactados gracias a la mediación de la Fundación ONCE, y 30 sujetos no ciegos, profesores del Departamento de Biblioteconomía y Documentación de la Universidad de Barcelona. El estudio muestra que la localización de los datos contenidos en tablas se ve facilitada en documentos HTML por la inclusión de un sumario que vincule con la tabla, así como la inclusión de tablas completas en el cuerpo del documento HTML facilita la actividad lectora por parte de los usuarios ciegos. A nivel metodológico la presente investigación aporta dos novedades relevantes respecto a la literatura existente en los estudios de usabilidad con ciegos: estudia la usabilidad del formato PDF y es un test de usabilidad cuantitativo; este último hecho dificulta su comparación con la mayoría de artículos publicados. Abstract: This paper analyses the problems of accessibility posed by scientific articles published in digital format, focusing on the ease of use of their content with respect to the form in which they are published (irrespective of the recovery system). The two most widely used formats for the publication of scientific articles in digital format, HTML and PDF, are analysed, examining reader performance in relation to the presence of contents lists or internal or linked tables. The study involved two groups: 30 blind subjects, all JAWS users, contacted through the ONCE Foundation, and 30 sighted subjects, lecturers in the Department of Librarianship and Documentation of the University of Barcelona. The results shows the location of data in tables is easier in HTML documents through the inclusion of a contents list linked to these tables. Further, the inclusion of complete tables in the body of HTML document facilitates the reading activity of blind users. At the methodological level, this work reports two novelties with respect to the existing literature on usability by blind people: it examines the usability of the PDF format, and discusses a quantitative usability test. The latter hinders comparison with the majority of published articles.
Predictive value of readiness, importance, and confidence in ability to change drinking and smoking.
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BACKGROUND: Visual analog scales (VAS) are sometimes used to assess change constructs that are often considered critical for change. Aims of Study: 1.) To determine the association of readiness to change, importance of changing and confidence in ability to change alcohol and tobacco use at baseline with the risk for drinking (more than 21 drinks per week/6 drinks or more on a single occasion more than once per month) and smoking (one or more cigarettes per day) six months later. 2.) To determine the association of readiness, importance and confidence with alcohol (number of drinks/week, number of binge drinking episodes/month) and tobacco (number of cigarettes/day) use at six months. METHODS: This is a secondary analysis of data from a multi-substance brief intervention randomized trial. A sample of 461 Swiss young men was analyzed as a prospective cohort. Participants were assessed at baseline and six months later on alcohol and tobacco use, and at baseline on readiness to change, importance of changing and confidence in ability to change constructs, using visual analog scales ranging from 1-10 for drinking and smoking behaviors. Regression models controlling for receipt of brief intervention were employed for each change construct. The lowest level (1-4) of each scale was the reference group that was compared to the medium (5-7) and high (8-10) levels. RESULTS: Among the 377 subjects reporting unhealthy alcohol use at baseline, mean (SD) readiness, importance and confidence to change drinking scores were 3.9 (3.0), 2.7 (2.2) and 7.2 (3.0), respectively. At follow-up, 108 (29%) reported no unhealthy alcohol use. Readiness was not associated with being risk-free at follow-up, but high importance (OR 2.94; 1.15, 7.50) and high confidence (OR 2.88; 1.46, 5.68) were. Among the 255 smokers at baseline, mean readiness, importance and confidence to change smoking scores were 4.6 (2.6), 5.3 (2.6) and 5.9 (2.7), respectively. At follow-up, 13% (33) reported no longer smoking. Neither readiness nor importance was associated with being a non-smoker, whereas high confidence (OR 3.29; 1.12, 9.62) was. CONCLUSIONS: High confidence in ability to change was associated with favorable outcomes for both drinking and smoking, whereas high importance was associated only with a favorable drinking outcome. This study points to the value of confidence as an important predictor of successful change for both drinking and smoking, and shows the value of importance in predicting successful changes in alcohol use. TRIAL REGISTRATION NUMBER: ISRCTN78822107.
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Excitation-continuous music instrument control patterns are often not explicitly represented in current sound synthesis techniques when applied to automatic performance. Both physical model-based and sample-based synthesis paradigmswould benefit from a flexible and accurate instrument control model, enabling the improvement of naturalness and realism. Wepresent a framework for modeling bowing control parameters inviolin performance. Nearly non-intrusive sensing techniques allow for accurate acquisition of relevant timbre-related bowing control parameter signals.We model the temporal contour of bow velocity, bow pressing force, and bow-bridge distance as sequences of short Bézier cubic curve segments. Considering different articulations, dynamics, and performance contexts, a number of note classes are defined. Contours of bowing parameters in a performance database are analyzed at note-level by following a predefined grammar that dictates characteristics of curve segment sequences for each of the classes in consideration. As a result, contour analysis of bowing parameters of each note yields an optimal representation vector that is sufficient for reconstructing original contours with significant fidelity. From the resulting representation vectors, we construct a statistical model based on Gaussian mixtures suitable for both the analysis and synthesis of bowing parameter contours. By using the estimated models, synthetic contours can be generated through a bow planning algorithm able to reproduce possible constraints caused by the finite length of the bow. Rendered contours are successfully used in two preliminary synthesis frameworks: digital waveguide-based bowed stringphysical modeling and sample-based spectral-domain synthesis.
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The present study was carried out to check whether classic osteometric parameters can be determined from the 3D reconstructions of MSCT (multislice computed tomography) scans acquired in the context of the Virtopsy project. To this end, four isolated and macerated skulls were examined by six examiners. First the skulls were conventionally (manually) measured using 32 internationally accepted linear measurements. Then the skulls were scanned by the use of MSCT with slice thicknesses of 1.25 mm and 0.63 mm, and the 33 measurements were virtually determined on the digital 3D reconstructions of the skulls. The results of the traditional and the digital measurements were compared for each examiner to figure out variations. Furthermore, several parameters were measured on the cranium and postcranium during an autopsy and compared to the values that had been measured on a 3D reconstruction from a previously acquired postmortem MSCT scan. The results indicate that equivalent osteometric values can be obtained from digital 3D reconstructions from MSCT scans using a slice thickness of 1.25 mm, and from conventional manual examinations. The measurements taken from a corpse during an autopsy could also be validated with the methods used for the digital 3D reconstructions in the context of the Virtopsy project. Future aims are the assessment and biostatistical evaluation in respect to sex, age and stature of all data sets stored in the Virtopsy project so far, as well as of future data sets. Furthermore, a definition of new parameters, only measurable with the aid of MSCT data would be conceivable.
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El debat sobiranista català està a l‟ordre del dia i actualment no passa desapercebut en cap mitjà de comunicació ni tampoc en el món polític, econòmic i empresarial. El fet d‟estar tan viva una temàtica així de delicada està ocasionant controvèrsies dins l‟empresariat català o que té la seva empresa ubicada a Catalunya perquè tot plegat provoca moltes incerteses, que són el pitjor enemic dels empresaris i dels negocis. Tanmateix, però, les informacions publicades o emeses venen marcades per les opinions polítiques i periodístiques, que es troben censurades en certa mesura perquè segueixen una determinada línia política i/o editorial. Per això s‟ha elaborat un reportatge digital focalitzat en l‟empresariat català i l‟encaix Catalunya-Espanya que pretén aportar noves valoracions entorn a aquest debat donant veu a empresaris i professionals, entre altres. La part teòrica de la memòria defineix els conceptes bàsics que són de forçat coneixement per realitzar una part pràctica que ha de ser entesa per qualsevol persona i que s‟ha de tractar amb la major objectivitat possible. Per això, el web http://laquestiocatalana.cat aporta un llenguatge planer i les eines bàsiques per donar a conèixer una matèria molt criticada per alguns sectors. A través d‟entrevistes a personatges rellevants, el web introdueix nous punts de vista sobre una qüestió marcada, a simple vista, per la preocupació d‟un possible boicot per part d‟Espanya. Però aquesta no sembla ser la principal inquietud dels entesos, i és que hi ha altres aspectes encara més alarmants que poden influir en l‟empresariat i que no són tractats per cap mitjà de comunicació convencional.
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The main difficulty in the successful treatment of metastatic melanoma is that this type of cancer is known to be resistant to chemotherapy. Chemotherapy remains the treatment of choice, and dacarbazine (DTIC) is the best standard treatment. The DM-1 compound is a curcumin analog that possesses several curcumin characteristics, such as antiproliferative, antitumor, and antimetastatic properties. The objective of this study was to evaluate the signaling pathways involved in melanoma cell death after treatment with DM-1 compared to the standard agent for melanoma treatment, DTIC. Cell death was evaluated by flow cytometry for annexin V and iodide propide, cleaved caspase 8, and TNF-R1 expression. Hoechst 33342 staining was evaluated by fluorescent microscopy; lipid peroxidation and cell viability (MTT) were evaluated by colorimetric assays. The antiproliferative effects of the drugs were evaluated by flow cytometry for cyclin D1 and Ki67 expression. Mice bearing B16F10 melanoma were treated with DTIC, DM-1, or both therapies. DM-1 induced significant apoptosis as indicated by the presence of cleaved caspase 8 and an increase in TNF-R1 expression in melanoma cells. Furthermore, DM-1 had antiproliferative effects in this the same cell line. DTIC caused cell death primarily by necrosis, and a smaller melanoma cell population underwent apoptosis. DTIC induced oxidative stress and several physiological changes in normal melanocytes, whereas DM-1 did not significantly affect the normal cells. DM-1 antitumor therapy in vivo showed tumor burden decrease with DM-1 monotherapy or in combination with DTIC, besides survival rate increase. Altogether, these data confirm DM-1 as a chemotherapeutic agent with effective tumor control properties and a lower incidence of side effects in normal cells compared to DTIC.
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In this review, we summarize how the new concept of digital optics applied to the field of holographic microscopy has allowed the development of a reliable and flexible digital holographic quantitative phase microscopy (DH-QPM) technique at the nanoscale particularly suitable for cell imaging. Particular emphasis is placed on the original biological information provided by the quantitative phase signal. We present the most relevant DH-QPM applications in the field of cell biology, including automated cell counts, recognition, classification, three-dimensional tracking, discrimination between physiological and pathophysiological states, and the study of cell membrane fluctuations at the nanoscale. In the last part, original results show how DH-QPM can address two important issues in the field of neurobiology, namely, multiple-site optical recording of neuronal activity and noninvasive visualization of dendritic spine dynamics resulting from a full digital holographic microscopy tomographic approach.
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The SHRP Modified Georgia Digital Faultmeter was loaned to the Iowa Department of Transportation in January 1993 for evaluation. A study was undertaken comparing the faultmeter to Iowa's current method of fault measurement. The following conclusions were made after comparing the faultmeter to Iowa's gauge: The faultmeter was lighter and easier to maneuver and position. The faultmeter's direct readout was quicker to read. The faultmeter has increased precision. The faultmeter gave consistently lower fault readings than the Iowa gauge.
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Context: Ovarian tumors (OT) typing is a competency expected from pathologists, with significant clinical implications. OT however come in numerous different types, some rather rare, with the consequence of few opportunities for practice in some departments. Aim: Our aim was to design a tool for pathologists to train in less common OT typing. Method and Results: Representative slides of 20 less common OT were scanned (Nano Zoomer Digital Hamamatsu®) and the diagnostic algorithm proposed by Young and Scully applied to each case (Young RH and Scully RE, Seminars in Diagnostic Pathology 2001, 18: 161-235) to include: recognition of morphological pattern(s); shortlisting of differential diagnosis; proposition of relevant immunohistochemical markers. The next steps of this project will be: evaluation of the tool in several post-graduate training centers in Europe and Québec; improvement of its design based on evaluation results; diffusion to a larger public. Discussion: In clinical medicine, solving many cases is recognized as of utmost importance for a novice to become an expert. This project relies on the virtual slides technology to provide pathologists with a learning tool aimed at increasing their skills in OT typing. After due evaluation, this model might be extended to other uncommon tumors.
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Objective. Collaborative quality improvement programs have been successfully used to manage chronic diseases in adults and acute lung complications in premature infants. Their effectiveness to improve pain management in acute care hospitals is currently unknown. The purpose of this study was to determine whether a collaborative quality improvement program implemented at hospital level could improve pain management and overall pain relief. Design.To assess the effectiveness of the program, we performed a before-after trial comparing patient's self-reported pain management and experience before and after program implementation. We included all adult patients hospitalized for more than 24 hours and discharged either to their home or to a nursing facility, between March 1, 2001 and March 31, 2001 (before program implementation) and between September 15, 2005 and October 15, 2005 (after program implementation). Setting.A teaching hospital of 2,096 beds in Geneva, Switzerland. Patients.All adult patients hospitalized for more than 24 hours and discharged between 1 to 31 March 2001 (before program) and 15 September to 15 October 2005 (after program implementation). Interventions.Implementation of a collaborative quality improvement program using multifaceted interventions (staff education, opinion leaders, patient education, audit, and feedback) to improve pain management at hospital level. Outcome Measures.Patient-reported pain experience, pain management, and overall hospital experience based on the Picker Patient Experience questionnaire, perceived health (SF-36 Health survey). Results.After implementation of the program only 2.3% of the patients reported having no pain relief during their hospital stay (vs 4.5% in 2001, P = 0.05). Among nonsurgical patients, improvements were observed for pain assessment (42.3% vs 27.9% of the patients had pain intensity measured with a visual analog scale, P = 0.012), pain management (staff did everything they could to help in 78.9% vs 67.9% of cases P = 0.003), and pain relief (70.4% vs 57.3% of patients reported full pain relief P = 0.008). In surgical patients, pain assessment also improved (53.7.3% vs 37.6%) as well as pain treatment. More patients received treatments to relieve pain regularly or intermittently after program implementation (95.1% vs 91.9% P = 0.046). Conclusion.Implementation of a collaborative quality improvement program at hospital level improved both pain management and pain relief in patients. Further studies are needed to determine the overall cost-effectiveness of such programs.