1,720,970 research outputs found
Determinazione di tossine algali (microcistine e nodularina) nelle acque superficiali
Full text linkViene proposto un metodo analitico per la determinazione dei principali congeneri delle microcistine (MCs) e della nodularina (NOD) presenti in campioni di acqua sia in fase disciolta (extracellulare) che all’interno delle cellule algali (endocellulare). Le due frazioni, extra ed endocellulare, vengono separate mediante filtrazione del campione acquoso. Le microcistine citoplasmatiche vengono estratte, previa procedura di congelamento-scongelamento della componente cellulare, con solvente organico in bagno ad ultrasuoni. Le tossine algali presenti nel campione in forma disciolta vengono invece concentrate mediante SPE (Solid-Phase Extraction) su fase C18. Entrambi gli estratti possono essere analizzati in HPLC-DAD, LC-MS o con il saggio ELISA
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Digital assessment of dental parameters in Italian and Mozambican subjects with ideal occlusion and permanent dentition
No full textObjective: To obtain reference values for tip, torque and in-out from digital models of Italian and Mozambican subjects in ideal occlusion using a repeatable and validated method and to compare these measurements with previously reported values. Material and Methods: Dental parameters were acquired from digital models of each subject, categorized to one of two groups: Italians (23 males, 27 females; mean age 28.3 years, ±5.7 years) and Mozambicans (14 males, 15 females; mean age, 23.4 years, ±5.9), using VAM software. All subjects had ideal occlusion, permanent dentition and no previous orthodontic treatment, fillings or prostheses. After normality of data was assumed (p<0.05), a paired t-test was performed to detect any statistical differences between the two groups (p<0.05). Then, classical inference (t-test and power analysis) was used to compare our data to those reported by other authors. Results: Mozambicans’ incisors were more proclined, while their upper molars appeared to be more prominent regarding Italians’. Italians shown greater tip values, especially at the upper first premolars and lower first molars. In-out values were comparable between the two groups, except for the upper molars (more prominent in Mozambicans) and lower first molar (more prominent in Italians). Unlike other reports, upper second molars displayed negative tip in our samples. Conclusion: Pre-adjusted appliances with standard prescription should not be expected to guarantee optimal outcomes. Prescriptions specific for ethnicities are recommended and reference values should be reconsidered
Evaluation of Tooth Movement Accuracy with Aligners: A Prospective Study
Full text linkBackground. Clear aligners treatment (CAT) is a common solution in orthodontics to treat both simple and complex malocclusions. This study aimed to evaluate the predictability of CAT, comparing the virtually planned and the achieved tooth movement at the end of stage 15, which is often the time of first refinement. Methods. Seventeen patients (mean age: 28.3 years) were enrolled in the study. Torque, tip and rotation were analyzed in 238 maxillary teeth on digital models at Pre-treatment (T0), at the end of stage 15 (T15) and at virtually planned stage 15 (T15i). Prescription, Achieved movement and performance values were calculated to compare the virtually planned and the clinical tooth position. Data were analyzed by means of Student’s t test with a level of significance set at p < 0.05. Results. The largest iper-performance was the torque correction of the second molars (+2.3° ± 3.1°), the greatest under-performance was the tip correction of the first molars (−2.3° ± 3.3°), while rotation corrections of all the teeth showed more accurate performance. No significant differences were found between mean Prescription and mean Achieved movement for all the assessed movements (p < 0.05). Conclusions. An accurate evaluation of CAT after the 15th aligner is fundamental in order to individuate the movements that are not matching the digital set-up
Is a non-radiological-assisted method valid for establishing crown-root relationships in an orthodontic set-up incorporating the roots? A retrospective study
No full textIntroduction: This study aimed to obtain information on the relationship between crown and root in terms of morphology – dimensions and crown-root angles –to be used for orthodontic set-ups without the use of radiological examinations. Material and methods: All the good quality CBCTs of patients obeying the eligibility criteria, from 2000 to 2015, were analysed. All teeth were analysed except for third molars. Six variables were evaluated: crown (CL) and root length (RL), crown width (CW), root width (RW), crown-root angles in both the frontal (CR-frontal) and sagittal plane (CR-sagittal). All teeth were divided into 3 groups according to number of root (single, two, three-rooted). The measurements were assessed with the Invivo professional software and then, subjected to correlation matrices and linear regression statistical analysis in order to find any significant correlations between crown and root measurements (α ≤ 0.05). Results: Seventy-three out of 247 good quality CBCTs were assessed. Correlation matrices statistical analysis showed linear correlations for some variables investigated, especially for CW/RW pairing in all subgroups (r = 0.81, r = 0.70 and r = 0.58 respectively for single-, two- and three-rooted) and CL/RL in the single-rooted subgroup (r = 0.29). Subsequent linear regression analysis allowed to obtain information about roots starting from crown measurements by means of equations [RW = 0.76 + (0.73 × CW) and RL = 10.94 + (0.25 × CL) for single-rooted teeth; RL = 1.11 + (0.73 × CW) and RW = 0.99 + (0.76 × CW), respectively for single- and two-rooted teeth]. No linear correlation was found between crown measurements and C-R angular values. Conclusion: It is possible to obtain root information starting from some crown measurements but these do not fulfil the need of minimal information to guarantee a perfect root position starting from that of crown
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Early versus late tracheal intubation in COVID-19 patients: A "pros/cons" debate also considering heart-lung interactions
Full text linkThe best timing of orotracheal intubation and invasive ventilation in COVID-19 patients with acute respiratory distress syndrome is unknown. The use of non-invasive ventilation, a life-saving technique in many medical conditions, is debated in patients with ARDS since prolonged NIVand delayed intubation may be harmful. Shortage of intensive care beds and ventilators during a respiratory pandemic can trigger a widespread use of early non-invasive ventilation in many hospitals but which is the best way to ventilate patients with severe bilateral pneumonia and severely increased spontaneous ventilation is controversial. Moreover, viral spreading to health-care workers and other hospitalized patients is an issue for any device used to administer oxygen. Even if protective mechanical ventilation is currently the gold standard for the management of acute respiratory distress syndrome, tracheal intubation is not without risks and is associated with delirium, hemodynamic instability, immobilization and post intensive care syndrome. Both invasive and non-invasive ventilation are associated with advantages and limitations that should be carefully considered when patients with COVID-19-ARDS need our attention. In the absence of strong evidence, in this review we highlight all the pro and con of these two different approaches
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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