169,915 research outputs found
Rupe-Type Rearrangement Intercepted by Diels–Alder Cycloaddition on Osmium
No full textAn
orthometallated 1-naphthylketone has been generated on osmium
by coupling of γ-hydroxyalkynyl and diphenylallenylidene ligands.
Treatment of Os{CC–C(OH)Ph2}2(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}(1) with HBF4 leads to [Os{κ2-O,C-[OC(CHPh2)-naphthyl-Ph]}(C–CHCPh2){κ3-P,O,P-[xant(PiPr2)2]}](BF4)2 (2), which gives [Os{κ2-O,C-[OC(CHPh2)-naphthyl-Ph]}(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (3) by deprotonation with (piperidinomethyl)polystyrene. The formation
of the ketone of 2 and 3 is an HF-catalyzed
process. The H+ and F– fragments of HF
are introduced sequentially with two different HBF4 molecules.
The first molecule delivers H+, while the second provides
F–. The proton from the first molecule adds to the
Cβ atom of the diphenylallenylidene ligand of 1 to form [Os{CC–C(OH)Ph2}2(C–CHCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (4). The
hydroxide group from a γ-hydroxyalkynyl of 4 is
removed with the proton of the second HBF4 molecule, whereas
the osmium center abstracts a fluoride of [BF4]−, to give [OsF{C[−CC–C(OH)Ph2]–CHCPh2}(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (5). Once both fragments of HF are
strategically located, the alkenyl-(γ-hydroxyalkynyl)alkylidene
ligand experiences a Rupe-type rearrangement intercepted by a Diels–Alder
cycloaddition, in two steps. A dehydration intercepted by Diels–Alder
cycloaddition initially occurs, which affords the fluoroalkenylnaphthyl
derivative [Os{κ2-F,C-[FC(CPh2)-naphthyl-Ph]}(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (7). The subsequent reaction of the
latter with water yields the orthometallated 1-naphthylketone of 3, releasing HF. The protonation of 3 with HBF4 leads to 2
Rupe-Type Rearrangement Intercepted by Diels–Alder Cycloaddition on Osmium
No full textAn
orthometallated 1-naphthylketone has been generated on osmium
by coupling of γ-hydroxyalkynyl and diphenylallenylidene ligands.
Treatment of Os{CC–C(OH)Ph2}2(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}(1) with HBF4 leads to [Os{κ2-O,C-[OC(CHPh2)-naphthyl-Ph]}(C–CHCPh2){κ3-P,O,P-[xant(PiPr2)2]}](BF4)2 (2), which gives [Os{κ2-O,C-[OC(CHPh2)-naphthyl-Ph]}(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (3) by deprotonation with (piperidinomethyl)polystyrene. The formation
of the ketone of 2 and 3 is an HF-catalyzed
process. The H+ and F– fragments of HF
are introduced sequentially with two different HBF4 molecules.
The first molecule delivers H+, while the second provides
F–. The proton from the first molecule adds to the
Cβ atom of the diphenylallenylidene ligand of 1 to form [Os{CC–C(OH)Ph2}2(C–CHCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (4). The
hydroxide group from a γ-hydroxyalkynyl of 4 is
removed with the proton of the second HBF4 molecule, whereas
the osmium center abstracts a fluoride of [BF4]−, to give [OsF{C[−CC–C(OH)Ph2]–CHCPh2}(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (5). Once both fragments of HF are
strategically located, the alkenyl-(γ-hydroxyalkynyl)alkylidene
ligand experiences a Rupe-type rearrangement intercepted by a Diels–Alder
cycloaddition, in two steps. A dehydration intercepted by Diels–Alder
cycloaddition initially occurs, which affords the fluoroalkenylnaphthyl
derivative [Os{κ2-F,C-[FC(CPh2)-naphthyl-Ph]}(CCCPh2){κ3-P,O,P-[xant(PiPr2)2]}]BF4 (7). The subsequent reaction of the
latter with water yields the orthometallated 1-naphthylketone of 3, releasing HF. The protonation of 3 with HBF4 leads to 2
La Geologia della Rupe di San Leo
No full textL’obiettivo principale di questo articolo è di presentare la nuova carta geologica in scala 1/2000 della Rupe di San Leo (versione ridotta in Figura 1). La carta è il primo passo dell’elaborazione di un modello tridimensionale che possa esprimere in modo immediato le relazioni tra stratigrafia, tettonica e geomorfologia che hanno determinato lo sviluppo di questa spettacolare e delicata forma del rilievo in Val Marecchia
Sponsorship in the enhancement of Cultural Heritage and the role of Creative Industry: some evaluative aspects
No full textLa Geologia della Rupe di San Leo
No full textL’articolo illustra una nuova carta geologica in scala 1/2000 della Rupe di San Leo, che è una spettacolare e delicata forma del rilievo posta al centro della Coltre della Val Marecchia. La Rupe è costituita da una successione epiligure che comprende i calcari della F.ne di San Marino e le arenarie della F.ne di Monte Fumaiolo, mentre il substrato della Rupe è costituito da unità liguri prevalentemente argillose. Per mostrare la geometria tridimensionale degli ammassi rocciosi che compongono la Rupe, alla carta geologica 1/2000 sono stati aggiunti dieci line-drawing dei confini geologici affioranti nelle pareti perimetrali. Dall’interpretazione dei dati rilevati sono stati ricavati caratteri stratigrafici inediti e una ben definita cronologia di deformazione. L’elemento tettonico più interessante è la grande faglia distensiva a basso angolo, di origine gravitativa, che affiora alla base delle pareti W, S ed E della Rupe. La faglia di San Leo fa parte di un sistema riconoscibile dal Monte Fumaiolo a Perticara, Torriana, Verucchio e San Marino. Il rilevamento e la datazione di questo sistema di faglie è essenziale per ricostruire la cinematica della coltre della Val Marecchia
Clinician- and patient-reported outcomes following the surgical treatment of single gingival recession defects: A systematic review
No full textTo analyze the effect of root coverage surgical therapy for the treatment of single gingival recession defects (GRD) in terms of clinician- and patient-reported outcomes (CROs and PROs), with an emphasis on esthetic perception. The protocol of this PRISMA 2020-compliant systematic review was registered in PROSPERO (CRD517050). Relevant articles reporting the outcomes of randomized controlled trials (RCTs) were identified through a literature search. After final article selection, according to specific eligibility criteria, data were extracted and categorized. Primary outcomes were clinician-reported root coverage esthetic scores (RES) and patient-reported esthetic perception and satisfaction using different assessment methods, such as standardized visual analog scales (VAS). Data were analyzed and the risk of bias in all included studies was assessed. Fifty-eight articles pertaining to 50 different RCTs were selected. A total of 1820 subjects presenting 2219 single GRDs were treated. Key findings derived from the pooled estimates indicated that root coverage and gingival phenotype modification therapy positively influenced both RES and patient-reported esthetic perception and satisfaction values. Compared to the use of a coronally advanced flap (CAF) alone (i.e., monolaminar technique), the use of a CAF in conjunction with a subepithelial connective tissue graft (i.e., bilaminar technique) had a positive impact on both RES and VAS values, whereas CAF in conjunction with soft tissue substitutes only had a beneficial effect on VAS values. Surgical approaches based on lateral flap displacement were associated with superior mean RES values compared to techniques involving coronal flap displacement. Meta-regression analyses revealed a statistically significant positive association between mean root coverage and RES (i.e., the greater the percentage of root coverage, the higher the RES). Conversely, the association between patient-reported esthetic perception and MRC was not statistically significant. In addition, it was observed that dentinal hypersensitivity can be substantially reduced with surgical root coverage therapy, regardless of the treatment modality. Surgical therapy for the correction of single GRDs had a positive effect on both clinician-reported esthetic scores and patient-reported esthetic perception and satisfaction. Bilaminar techniques are generally associated with superior results. © 2025 The Author(s). Periodontology 2000 published by John Wiley & Sons Ltd
Oral juvenile xanthogranuloma: An unusual presentation in an adult patient and a systematic analysis of published cases
No full textObjective. The purpose of this study was to describe an unusual case of intraoral juvenile xanthogranuloma (JXG) and to perform a systematic review to investigate the available literature regarding oral JXGs. Study design. We present a new case of oral JXG arising in a 36-year-old Italian woman and conducted a systematic literature review in PubMed, Web of Science, and Scopus, according to the PRISMA guidelines. Results. Our review of the English-language literature yielded 34 cases of oral JXG, which included our case report. Conclusions. JXG is a non-Langerhans cell histiocytosis. Oral JXG has been reported, but it is a rare manifestation. Because of the rarity of oral lesions and possible variations in the clinical and histologic presentation, the correct diagnosis can be challenging, requiring a careful clinical and histopathologic evaluation with adjuvant immunohistochemical studies
Repair of teeth with cracks in crowns and roots: An observational clinical study
No full textAim: This retrospective observational study investigated the survival rate of teeth with radicular cracks that were restored using composite materials. Methodology: The study was approved by the Ethical Committee of Sistema Sanitario Nazionale (prot. N°2370CELazio1), Clinicaltrials.gov identifier: NCT04430205. Between 1991 and 2019, 87 teeth with radicular cracks (87 patients [46 men, 41 women, mean age 50.2 years]) were treated with adhesive composite restorations. Forty-five cracks were observed in the maxillary posterior teeth (molars and premolars), 40 in the mandibular posterior teeth and only two cracks in the anterior teeth, both in maxilla. Based on the depth of the crack, teeth were categorized as proximal radicular cracked teeth (PRCT), in which the fracture line was restricted within the pulpal floor or the coronal one-third of the root and deep radicular cracked teeth (DRCT), in which the fracture line extended to the middle and apical thirds of the root canal up to the apex. Bone loss/recovery was evaluated radiographically at 1-year follow-up. All patients were treated using surgical microscopy by the same operator. Logistic regression analysis was performed to determine independent predictors of extraction. Kaplan–Meier survival curves were used to analyse PRCT and DRCT. Results: Among 87 cracked teeth, 66 were molars, 19 premolars and 2 incisors. Fifty-two were DRCT, 35 were PRCT, 46 had a periodontal probing defect. Patients were followed up for a mean of 66.9 months (standard deviation 44.6, min 1 to max 172). Lack of probing depth was a significant protective factor against extraction (odds ratio [OR] 0.027, 95% confidence interval [CI] 0.003–0.27, p <.05), whereas further bone loss (OR 10.63, 95% CI 2.08–54.36, p <.05) was a risk factor for extraction. More than 50% of teeth treated with the adhesive protocol were functional (46 of 87 teeth [χ2 test], p <.05) at 5-year follow-up. Among the PRCT group, a 78% survival rate at 5 years was found, while among the DRCT group, a 58% survival rate was found. Conclusion: Composite resin restorations resulted in tooth survival in >50% of patients; 85.4% of PRCT and 61.5% of DRCT were functional after 5 years of follow-up
Endodontic Clinical Outcome after Separated Instrument Removal Using a Spinal Needle Technique: A Retrospective Study of Thirty Years of Clinical Experience
No full textIntroduction: Current methods for the removal of separated endodontic instruments (RSI) are not predictable. Methods: The primary outcome of this retrospective study was to assess the clinical and radiographic success (CRS) of teeth in case of RSI after a 5-year follow-up. Secondary outcomes were to evaluate (1) the effectiveness in RSI and (2) the risk of root fracture after RSI. The study protocol was registered at ClinicalTrials.gov (ID: NCT05128266). The patients were treated by the same endodontist between January 1991 and December 2019. The RSI was performed under the operative microscope as follows: first, the dentine surrounding the coronal part of the broken instrument was selectively removed by using a small ultrasonic tip to loosen the fragment; then, a modified spinal needle was used to catch and remove the instrument. The 1-, 3-, 5-, and >5-year CRS were recorded. Logistic regression analysis was performed to determine independent predictors of failure (ie, tooth number, type of root canal, shape of the root canal, type of broken instrument, apicocoronal level of the separated instrument, presence of periapical lesions, and root perforations). Results: A total of 158 teeth were included in this study. Finally, 131 instruments underwent RSI (82.9%). RSI was an independent predictor of CRS after 1-year of treatment (odds ratio: 58.3; 95% confidence interval: 27.42–95.73, P < .05). At the 5-year follow-up, only 10 of 131 teeth (7.6%) failed. All failures were caused by root fracture (10/10) (χ2 test, P < .05). Separated instruments located in the apical third of the root were more difficult to remove (13/49 cases, 26.5%; χ2 test, P < .05). Conclusions: The proposed technique can achieve excellent effectiveness in RSI, can achieve a high CRS rate when a periapical lesion is present, is not associated to a significant increase in root fracture incidence, and should be performed with the help of an operative microscope
Sodium-hyaluronate mouthwash on radiotherapy-induced xerostomia: a randomised clinical trial
No full textIntroduction Radiotherapy-induced xerostomia (RIX) is one of the most common adverse effects of radiotherapy (RT) in head and neck cancer patients (HNC) and a major determinant of survivors' quality of life. The primary objective was to evaluate the reduction of patients' xerostomia symptoms after the utilisation of a sodium-hyaluronate mouthwash compared to a placebo solution. The secondary objectives were to evaluate the improvement of quality of life and to evaluate the patients' satisfaction.Methods The protocol was approved by the ethical committee (Ref. 50,053/19) and registered at ClinicalTrials.gov (ID: NCT05103124). The study was a double-blind randomised clinical trial (RCT) with a crossover design and was conducted at the Fondazione Policlinico Universitario A. Gemelli, Rome.Results Thirty-two patients completed the study protocol. Lower values of the modified Xerostomia Questionnaire (XQ) were retrieved when comparing the baseline scores to the ones after the treatment, when compared with placebo (Mann-Whitney U test = 0.01); higher values of patients' satisfaction (Likert scale) and modified XQ were retrieved for the sodium-hyaluronate mouthwash (Mann-Whitney U test = 0.001).ConclusionsThis RCT highlights the advantages of treating RIX with the sodium-hyaluronate mouthwash since it seems to be clinically effective in reducing its symptoms, without any reported adverse events.ClinicalTrials.gov: NCT05103124 in 17/10/2021.Conclusions This RCT highlights the advantages of treating RIX with the sodium-hyaluronate mouthwash since it seems to be clinically effective in reducing its symptoms, without any reported adverse events.ClinicalTrials.gov: NCT05103124 in 17/10/2021
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