28 research outputs found

    Identification of hidden orbital contributions in the La_{0.65} Sr_{0.35} MnO_{3} valence band

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    Hybridization of electronic states and orbital symmetry in transition metal oxides are generally considered key ingredients in the description of both their electronic and magnetic properties. In the prototypical case of La_{0.65} Sr_{0.35} MnO_{3} (LSMO), a landmark system for spintronics applications, a description based solely on Mn 3d and O 2p electronic states is reductive. We thus analyzed elemental and orbital distributions in the LSMO valence band through a comparison between density functional theory calculations and experimental photoelectron spectra in a photon energy range from soft to hard x rays. We reveal a number of hidden contributions, arising specifically from La 5p, Mn 4s, O 2s orbitals, considered negligible in previous analyses; our results demonstrate that all these contributions are significant for a correct description of the valence band of LSMO and of transition metal oxides in general

    Ultrafast spectroscopy with spin polarization

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    A project for the design and r.alization of an experimental station dedicated to ultrafast spin polarization dynamics allowing for spin polarization measurements of photoelectron yield as excited by free electron laser pulses is presented

    Periodontal Effects of a Transposed Versus a Conventional Flap in Mandibular Third Molar Extractions

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    The aim of this study was to compare a transposed with a repositioned flap by assessing the periodontal effects on the second molar and primary healing after extraction of partially impacted lower third molars. A total of 24 patients requiring partially impacted mandibular wisdom tooth removal were enrolled in the study. The test group (n = 12) underwent a transposed flap procedure, whereas the control group (n = 12) underwent a repositioned flap procedure. Plaque index, probing depth, bleeding on probing, and width of keratinized tissue were recorded the day of surgery (T1) and after 60 days (T4). Wound dehiscence was assessed on the mesio-distal and bucco-lingual directions at days 2 (T2), 7 (T3), and T4. No significant differences have been observed in the periodontal parameters between the groups at T1 and T4 (P > 0.05). Similarly, no difference was found at T2, T3, and T4 in wound dehiscence incidence (P > 0.05). To date, no data exists on the use of transposed flaps in third molar surgery; thus a comparison of results cannot be done. Further studies with larger population are needed to investigate the potential advantages of this type of flap

    Vernal keratoconjunctivitis: atopy and autoimmunity

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    BACKGROUND: Vernal Keratoconjunctivitis (VKC) is a rare chronic ocular inflammatory disease and it mainly affects boys in the first decade of life. Although it is a self-limiting disease, patients may present many phases characterized by an exacerbation of inflammatory symptoms with a consequent decline of the quality of life. PURPOSE: define the clinical and immunological profile of patients affected by VKC and investigate their familiar history of autoimmune disorders and their autoimmunity pattern. PATIENTS AND METHODS: 28 children were enrolled (20 males, 71%) aged between 4 and 14 years of life affected by VKC. Family history of allergic and immunological diseases was collected for each patient. In particular, it was asked whether some components of their families were affected by Hashimoto's thyroiditis, type I diabetes, psoriasis or rheumatoid arthritis and Systemic Lupus Erythematosus (SLE). All VKC children underwent a serological evaluation of antinuclear antibodies (ANA). RESULTS: A family history of immunological disorders was found in 46% of patients, 28% of Hashimoto's thyroiditis, 14% of type I diabetes, 14% of psoriasis, and 1 of Systemic Lupus Erythematosus. Furthermore, 35% of patients was ANA positive and they corresponded to patients with a higher ocular score and with the most important clinical symptoms. CONCLUSIONS: the detection of ANA positivity and of a familiar history of autoimmune disorders in a high percentage of children with VKC may help us to better understand the association of this ocular inflammatory disease with systemic autoimmune disorders and atopic condition

    Periodontal effects of a transposed versus a conventional flap in mandibular third molar extractions

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    The aim of this study was to compare a transposed with a repositioned flap by assessing the periodontal effects on the second molar and primary healing after extraction of partially impacted lower third molars. A total of 24 patients requiring partially impacted mandibular wisdom tooth removal were enrolled in the study. The test group (n = 12) underwent a transposed flap procedure, whereas the control group (n = 12) underwent a repositioned flap procedure. Plaque index, probing depth, bleeding on probing, and width of keratinized tissue were recorded the day of surgery (T1) and after 60 days (T4). Wound dehiscence was assessed on the mesio-distal and bucco-lingual directions at days 2 (T2), 7 (T3), and T4. No significant differences have been observed in the periodontal parameters between the groups at T1 and T4 (P > 0.05). Similarly, no difference was found at T2, T3, and T4 in wound dehiscence incidence (P > 0.05). To date, no data exists on the use of transposed flaps in third molar surgery; thus a comparison of results cannot be done. Further studies with larger population are needed to investigate the potential advantages of this type of flap

    Immunological features in children with vernal keratoconjunctivitis

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    Background: Vernal Keratoconjunctivitis (VKC) is a rare (<1:10 000 in Europe) chronic, bilateral, seasonally exacerbed inflammation of the ocular surface involving tarsal and/or bulbar conjunctiva. VKC especially affects male children and young boys and it tends to regress in puberty. The diagnosis is based on the common conjuncitval symptoms (itching, photophobia and tearing) and on the characteristic signs (giant papillae, conjunctival hyperaemia and Horner-Trantas dots on the limbal conjunctiva). Moreover, photophobia is a constant feature of the VKC. Aim: To define a clinical, anamnestic and immunological profile of patients with VKC evaluating also the presence of biomarker autoantibodies. Methods: The study was performed at the Immunology and Allergology service of the Pediatric Department, Policlinico Umberto I Hospital, Rome. We enrolled 28 children (18:M) aged 4–14 years with diagnosis of VKC made by an ophthalmologist. To each patient, we asked the family history of allergic and immunological diseases. Among the immunological disorders, we evaluated mainly the presence of Hashimoto′ s thyroiditis, type I diabetes, psoriasis, rheumatoid arthritis and Systemic Lupus Erythematosus (SLE). All patients with a diagnosis of VKC underwent to a serological evaluation with the dosage of ANA autoantibodies. Results: 17 patients (60.7%) patients reported a family history of allergic diseases. About the immunological disorders, one patient presented type 1 diabetes and 14 patients (53%) reported a positive family history for autoimmune diseases: 6 (21%) for Hashimoto′s thyroiditis, 4 (14%) for type I diabetes, 3 (10%) for psoriasis and one for Systemic Lupus Erythematosus. 10 (35.7%) patients were ANA positive and they tended to present an higher severity of VKC. The association between ANA positivity and the family history of immune disorders was not demonstrated. Conclusions: These findings encourage us to consider the VKC as a multifactorial disease that can not be explained only by an allergic mechanism. Moreover, among the patients with VKC, it is important to recognise those subgroups with certain anamnestic, clinical and serum characteristics in order to find out an appropriate therapeutic management and a careful follow-up

    Socket preservation with d-PTFE membrane: histologic analysis of the newly formed matrix at membrane removal

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    This study aimed to evaluate the efficacy of an exposed high-density polytetrafluoroethylene (d-PTFE) membrane in preventing epithelial migration in postextraction sockets. For this purpose, a histologic description of the newly formed soft tissue underlying the membrane is presented. The periodontal status of the adjacent teeth was also evaluated to assess the gingival response. Ten premolar extraction sockets were treated. After tooth extraction, the sockets were filled with nanocrystalline hydroxyapatite and covered with d-PTFE membranes. Subperiosteal pockets were created to ensure the stability of the membranes. Membranes were left intentionally exposed and were atraumatically removed after 28 days. At that time, a bioptic specimen of the newly formed soft tissue under the membranes was taken. All the histologic samples showed a dense connective tissue without epithelial cells and no signs of foreign body reaction. No significant variation of the periodontal indices was observed on the teeth adjacent to the extraction sites. The study results indicate that exposed d-PTFE membranes can prevent epithelial migration in healing sockets without consequences on the periodontal healt

    Livelli sierici di resistina in bambini con Rinite Allergica

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    La resistina è una proteina sierica prodotta dagli adipociti e dai macrofagi circolanti con dimostrata attività proinfiammatoria. Molti autori hanno descritto un aumento dei livelli di questa adipochina sierica negli atopici con malattie respiratorie come la rinite allergica (RA)
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