199 research outputs found
Restauración de incisivo inferior fracturado mediante procedimientos de invasión mÃnima : reporte de un caso clÃnico
La odontologÃa está inmersa en un nuevo paradigma: no se puede pensar
en ninguna técnica restauradora sin que participen fenómenos de adhesión.
El desarrollo de pernos de fibra de vidrio, sumado a los procedimientos de restauraciones
adhesivas puede utilizarse como uno de los tantos recursos de la
odontologÃa de invasión mÃnima. Los pernos de fibra de vidrio ofrecen varias
ventajas: comportamiento anisótropo, módulo de elasticidad bajo, buena
resistencia mecánica, el lecho que aloja al perno de fibra requiere de una
mÃnima preparación y se cementan con cementos adhesivos con carga, permitiendo
de esta manera obtener una superficie homogénea que se interpone
entre el perno de fibra y los tejidos dentales, conectándolo a los tejidos del
conducto y sustituyendo mecánicamente la dentina.
El caso clÃnico que se reporta se presentó para su resolución en la ClÃnica
Integrada III F. O. UNCuyo durante el año lectivo 2009. El paciente presentaba
una fractura amelodentinaria desde hacÃa cuatro años, con compromiso
de la vitalidad y un proceso periapical. Durante los procedimientos endodónticos
se realizó una perforación de la pared del conducto que se selló mediante
la colocación de hidróxido de calcio y la obturación del mismo con conos
de gutapercha.
Se efectuó el seguimiento clÃnico y radiográfico del caso en donde se constató
la reparación del proceso apical y luego se procedió a la restauración del
elemento dentario con resinas compuestas con la ayuda de un poste de fibra
de vidrio cementado con cemento resinoso. Dadas las caracterÃsticas del tratamiento
endodóntico realizado, se decidió dejar más porción del cono de
gutapercha a pesar de lo aconsejado por numerosos autores, ya que de esta
manera se aseguró el sellado de la perforación radicular para evitar de esta
manera la nanofiltración hacia el interior del elemento dentario.Dentistry is immersed in a new paradigm: It is impossible to think of
any restoring technique without the participation of adhesion
phenomena.The development of fiber glass posts and adhesive restoration
procedures may be used as the most reliable technique in minimal
invasive dentistry. The fiber glass posts show many advantages: a) an
anisotropic behavior, b) low modulus of elasticity, c) good mechanical
resistance, d) the layer that lodges the fiber post requires a minimal
preparation, e) they are bond with loaded adherent cements, obtaining a
homogeneous surface that intervenes between the fiber post and the dental
tissues and, also, connecting the post to the tissues of the root canal and
substituting the dentine mechanically.
The obtained clinical case was submitted to “ClÃnica Integrada III"
FOUNCuyo during the academic year 2009 for its resolution. The
patient showed a dentoenamel fracture dating from 4 years, with a
compromised vitality and a periapical process. By means of endodontic
procedures, a hole was drilled in the root canal wall that was sealed by
placing calcium hydroxide and by sealing the gutta-percha cone. A
clinical and radiographic monitoring revealed the reparation of the
apical process. Then, the tooth was restored with composite resins and a
fiber glass post cemented with resin cement. Given the characteristics of
the endodontic treatment performed and, since the sealing allowed the
root perforation to avoid the nanofiltration into the tooth, it was decided
to leave a further portion of the gutta-percha cone despite the advice of
many authors.Fil: Carrazco, MarÃa E..
Universidad Nacional de Cuyo. Facultad de OdontologÃaFil: Ferrari, Pablo.
Universidad Nacional de Cuyo. Facultad de OdontologÃ
Prospects for Public Relations: Excellence Study results for communication in organizations
La comunicación en las organizaciones está afectada por variables tanto internas como externas a la organización, como la cultura, la estructura y la gestión organizativa. Algunos de los resultados del Excellence Study discutidos en el presente artÃculo evidencian que el valor de las relaciones públicas se crea en los relacionamientos que las organizaciones desarrollan con los públicos, especialmente con aquellos que se ubican en el interior mismo de la empresa.The communication in the organizations is affected by variables so much internal as day pupils to the organization, as the culture, the structure and the organizational management. Some of the results of the Excellence Study discussed in the present article demonstrate that the value of the public relations believes itself in the relational processes that the organizations develop with the public ones, specially with those that are located in the interior itself of the company
Resonant Kelvin-Helmholtz modes in sheared relativistic flows
Qualitatively new aspects of the (linear and non-linear) stability of sheared
relativistic (slab) jets are analyzed. The linear problem has been solved for a
wide range of jet models well inside the ultrarelativistic domain (flow Lorentz
factors up to 20; specific internal energies ). As a distinct
feature of our work, we have combined the analytical linear approach with
high-resolution relativistic hydrodynamical simulations, which has allowed us
i) to identify, in the linear regime, resonant modes specific to the
relativistic shear layer ii) to confirm the result of the linear analysis with
numerical simulations and, iii) more interestingly, to follow the instability
development through the non-linear regime. We find that very high-order
reflection modes with dominant growth rates can modify the global, long-term
stability of the relativistic flow. We discuss the dependence of these resonant
modes on the jet flow Lorentz factor and specific internal energy, and on the
shear layer thickness. The results could have potential applications in the
field of extragalactic relativistic jets.Comment: Accepted for publication in Physical Review E. For better quality
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How to Handle Concomitant Asymptomatic Prosthetic Joints During an Episode of Hematogenous Periprosthetic Joint Infection:a Multicenter Analysis
BACKGROUND: Prosthetic joints are at risk of becoming infected during an episode of bacteremia, especially during Staphylocococcus aureus bacteremia. However, it is unclear how often asymptomatic periprosthetic joint infection (PJI) occurs, and whether additional diagnostics should be considered. METHODS: In this multicenter study, we retrospectively analyzed a cohort of patients with a late acute (hematogenous) PJI between 2005-2015 who had concomitant prosthetic joints in situ. Patients without at least 1 year of follow-up were excluded. RESULTS: We included 91 patients with a hematogenous PJI and 108 concomitant prosthetic joints. The incident PJI was most frequently caused by Staphylococcus aureus (43%), followed by streptococci (26%) and Gram-negative rods (18%). Of 108 concomitant prosthetic joints, 13 were symptomatic, of which 10 were subsequently diagnosed as a second PJI. Of the 95 asymptomatic prosthetic joints, 1 PJI developed during the follow-up period and was classified as a "missed" PJI at the time of bacteremia with S. aureus (1.1%). Infected prosthetic joints were younger than the noninfected ones in 67% of cases, and prosthetic knees were affected more often than prosthetic hips (78%). CONCLUSIONS: During an episode of hematogenous PJI, concomitant asymptomatic prosthetic joints have a very low risk of being infected, and additional diagnostic work-up for these joints is not necessary
Profiling of Flavonol Derivatives for the Development of Antitrypanosomatidic Drugs
Flavonoids represent a potential source of new antitrypanosomatidic leads. Starting from a library of natural products, we combined target-based screening on pteridine reductase 1 with phenotypic screening on Trypanosoma brucei for hit identification. Flavonols were identified as hits, and a library of 16 derivatives was synthesized. Twelve compounds showed EC50 values against T. brucei below 10 \u3bcM. Four X-ray crystal structures and docking studies explained the observed structure-activity relationships. Compound 2 (3,6-dihydroxy-2-(3-hydroxyphenyl)-4H-chromen-4-one) was selected for pharmacokinetic studies. Encapsulation of compound 2 in PLGA nanoparticles or cyclodextrins resulted in lower in vitro toxicity when compared to the free compound. Combination studies with methotrexate revealed that compound 13 (3-hydroxy-6-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one) has the highest synergistic effect at concentration of 1.3 \u3bcM, 11.7-fold dose reduction index and no toxicity toward host cells. Our results provide the basis for further chemical modifications aimed at identifying novel antitrypanosomatidic agents showing higher potency toward PTR1 and increased metabolic stability
Comparison of prognostic models to predict the occurrence of colorectal cancer in asymptomatic individuals: a systematic literature review and external validation in the EPIC and UK Biobank prospective cohort studies
Objective: To systematically identify and validate published colorectal cancer risk prediction models that do not require invasive testing in two large population-based prospective cohorts. Design: Models were identified through an update of a published systematic review and validated in the European Prospective Investigation into Cancer and Nutrition (EPIC) and the UK Biobank. The performance of the models to predict the occurrence of colorectal cancer within 5 or 10 years after study enrolment was assessed by discrimination (C-statistic) and calibration (plots of observed vs predicted probability). Results: The systematic review and its update identified 16 models from 8 publications (8 colorectal, 5 colon and 3 rectal). The number of participants included in each model validation ranged from 41 587 to 396 515, and the number of cases ranged from 115 to 1781. Eligible and ineligible participants across the models were largely comparable. Calibration of the models, where assessable, was very good and further improved by recalibration. The C-statistics of the models were largely similar between validation cohorts with the highest values achieved being 0.70 (95% CI 0.68 to 0.72) in the UK Biobank and 0.71 (95% CI 0.67 to 0.74) in EPIC. Conclusion: Several of these non-invasive models exhibited good calibration and discrimination within both external validation populations and are therefore potentially suitable candidates for the facilitation of risk stratification in population-based colorectal screening programmes. Future work should both evaluate this potential, through modelling and impact studies, and ascertain if further enhancement in their performance can be obtained
Should the first blood pressure reading be discarded?
We evaluated the consequences of excluding the first of three blood pressure (BP) readings in different settings: a random population sample (POS, n=1525), a general practice office (GPO, n=942) and a specialized hypertension center (SHC, n=462). Differences between systolic and diastolic BP (SBP and DBP) estimates obtained including and excluding the first reading were compared and their correlation with ambulatory BP monitoring (ABPM) was estimated. The samples were divided into quartiles according to the difference between the third and the first SBP (3-1ΔSBP). SBP decreased through sequential readings, 3-1ΔSBP was -5.5 ± 9.7 mm Hg (P<0.001), -5.1 ± 10.4 mm Hg (P<0.001) and -6.1 ± 9.3 mm Hg (P<0.001) for POS, GPO and SHC, respectively. However, individuals included in the top quartile of 3-1ΔSBP showed their highest values on the third reading. The mean SBP estimate was significantly higher excluding the first reading (P<0.001), but the differences among both approaches were small (1.5-1.6 mm g). Moreover, the correlation between SBP values including and excluding the first reading and daytime ABPM were comparable (r = 0.69 and 0.68, respectively). Similar results were observed for DBP. In conclusion, our study does not support the notion of discarding the first BP measurement and suggests that it should be measured repeatedly, regardless the first value.Facultad de Ciencias Médica
Molecular Systematic of Three Species of Oithona (Copepoda, Cyclopoida) from the Atlantic Ocean: Comparative Analysis Using 28S rDNA
Species of Oithona (Copepoda, Cyclopoida) are highly abundant, ecologically important, and widely distributed throughout the world oceans. Although there are valid and detailed descriptions of the species, routine species identifications remain challenging due to their small size, subtle morphological diagnostic traits, and the description of geographic forms or varieties. This study examined three species of Oithona (O. similis, O. atlantica and O. nana) occurring in the Argentine sector of the South Atlantic Ocean based on DNA sequence variation of a 575 base-pair region of 28S rDNA, with comparative analysis of these species from other North and South Atlantic regions. DNA sequence variation clearly resolved and discriminated the species, and revealed low levels of intraspecific variation among North and South Atlantic populations of each species. The 28S rDNA region was thus shown to provide an accurate and reliable means of identifying the species throughout the sampled domain. Analysis of 28S rDNA variation for additional species collected throughout the global ocean will be useful to accurately characterize biogeographical distributions of the species and to examine phylogenetic relationships among them
Association between physical activity and risk of hepatobiliary cancers : A multinational cohort study
Background & Aims: To date, evidence on the association between physical activity and risk of hepatobiliary cancers has been inconclusive. Weexamined this association in the European Prospective Investigation into Cancer and Nutrition cohort (EPIC). Methods: We identified 275 hepatocellular carcinoma (HCC) cases, 93 intrahepatic bile duct cancers (IHBCs), and 164 non-gallbladder extrahepatic bile duct cancers (NGBCs) among 467,336 EPIC participants (median follow-up 14.9 years). We estimated cause-specific hazard ratios (HRs) for total physical activity and vigorous physical activity and performed mediation analysis and secondary analyses to assess robustness to confounding (e.g. due to hepatitis virus infection). Results: In the EPIC cohort, the multivariable-adjusted HR of HCC was 0.55 (95% CI 0.38-0.80) comparing active and inactive individuals. Regarding vigorous physical activity, for those reporting >2 hours/week compared to those with no vigorous activity, the HR for HCC was 0.50 (95% CI 0.33-0.76). Estimates were similar in sensitivity analyses for confounding. Total and vigorous physical activity were unrelated to IHBC and NGBC. In mediation analysis, waist circumference explained about 40% and body mass index 30% of the overall association of total physical activity and HCC. Conclusions: These findings suggest an inverse association between physical activity and risk of HCC, which is potentially mediated by obesity. Lay summary: In a pan-European study of 467,336 men and women, we found that physical activity is associated with a reduced risk of developing liver cancers over the next decade. This risk was independent of other liver cancer risk factors, and did not vary by age, gender, smoking status, body weight, and alcohol consumption. (C) 2019 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.Peer reviewe
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