177,117 research outputs found
Short term effects produced by Cervical headgear and Hilgers’ pendulum on head posture and on airway space
No full textThe study investigates the effects of cervical headgear (CHG) in the treatment of Class II malocclusion, focusing on changes in head and cervical posture, as well as upper airway and hyoid bone positioning. Maxillary molar distalization is a critical part of Class II treatment, and although the traditional approach using extraoral appliances like CHG offers stability, its aesthetic drawbacks and the need for patient compliance have led to the exploration of non-compliant alternatives.
The primary objective of the study was to assess how CHG affects the head and cervical posture, airway dimensions, and the position of the tongue and hyoid bone, in comparison with a control group treated with a Hilger’s Pendulum appliance. The study involved 40 subjects aged 11–14, divided into two groups: one treated with CHG and the other with the Pendulum appliance. Pre-treatment and post-treatment cephalometric radiographs were analyzed to assess these variables.
Results showed that CHG treatment caused a significant reduction in craniocervical angles, indicating a flexion of the head. Additionally, the cervical vertebrae moved forward, with a marked increase in the distance between C1 and C2. Furthermore, there was a reduction in upper airway space, a lengthening of the tongue by 9 mm, and an anterior and downward movement of the hyoid bone. These changes were statistically significant when compared to the control group. The Pendulum appliance, however, did not show similar significant changes.
The findings suggest that the use of CHG influences both craniofacial posture and airway dimensions, potentially contributing to mandibular advancement and improved airway space. Future studies could explore whether these changes persist after treatment
Head posture and lower arch dental crowding
No full textObjective: To test the null hypothesis that there is no relationship between the posture of the head and the neck and late lower arch crowding. Materials and Methods: The sample comprised 55 subjects (23 female, 32 male), age 12-18 years, with complete permanent dentition and without previous orthodontic treatment. Space conditions were valued by Nance's space analysis on the study models. Craniovertical, craniocervical, and craniohorizontal postural variables were recorded from lateral cephalograms. Student's t-test was performed to assess the differences of the postural angles between the two groups. Results: The results showed that the differences of the postural variables between the two groups are statistically significant. Subjects with more than 2 mm dental crowding had mean craniocervical angles (NSL/CVT, NSL/OPT, NL/CVT, NL/OPT) that were 5 degrees to 6 degrees larger than the subjects with the space conditions smaller than 2 mm (P <= .01). In addition, the mean craniohorizontal angles (CVT/Hor, OPT/Hor) in the subjects with lower dental crowding were 4 degrees smaller than subjects without dental crowding (P < .05). Conclusions: The hypothesis is rejected. A clear pattern of association between extended head posture and lower arch dental crowding was found
Treatment of hypothalamic infertility with pulsatile GN-RH administration.
No full textIn this study the Authors have obtained an ovulatory response using intravenous Gn-RH treatment in four patients with hypothalamic hypogonadotropic amenorrhea. The Gn-RH was administered in a pulsatile manner with a small portable autoinfusion pump (Autosyringe, Inc., Hooksett). The ovarian follicular maturation, as it appears from the pelvic echography, was perfectly similar to that observed in a spontaneous ovulatory cycle. Endocrine picture by serial determination of gonadotropin; prolactin, estradiol and progesterone concentrations showed hormone values to be in the normal range. During the therapy no complications were observed; at the present time no pregnancy has occurred
Circulating Antineutrophil Cytoplasmic Autoantibodies (anca) In 2 Cases of Tolosa-hunt Syndrome
No full textAppropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Is Tolosa-hunt Syndrome A Limited Form of Wegeners Granulomatosis? : Report of 2 Cases With Antineutrophil Cytoplasmic Antibodies
No full text"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Fibrocystic Disease of the Breast Associated with Pituitary‐Ovarian Dysfunction: Results of Treatment with Bromocriptine
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