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Adv Mater ; 33(39): e2103000, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34397123


The competing and non-equilibrium phase transitions, involving dynamic tunability of cooperative electronic and magnetic states in strongly correlated materials, show great promise in quantum sensing and information technology. To date, the stabilization of transient states is still in the preliminary stage, particularly with respect to molecular electronic solids. Here, a dynamic and cooperative phase in potassium-7,7,8,8-tetracyanoquinodimethane (K-TCNQ) with the control of pulsed electromagnetic excitation is demonstrated. Simultaneous dynamic and coherent lattice perturbation with 8 ns pulsed laser (532 nm, 15 MW cm-2 , 10 Hz) in such a molecular electronic crystal initiates a stable long-lived (over 400 days) conducting paramagnetic state (≈42 Ωcm), showing the charge-spin bistability over a broad temperature range from 2 to 360 K. Comprehensive noise spectroscopy, in situ high-pressure measurements, electron spin resonance (ESR), theoretical model, and scanning tunneling microscopy/spectroscopy (STM/STS) studies provide further evidence that such a transition is cooperative, requiring a dedicated charge-spin-lattice decoupling to activate and subsequently stabilize nonequilibrium phase. The cooperativity triggered by ultrahigh-strain-rate (above 106 s- 1 ) pulsed excitation offers a collective control toward the generation and stabilization of strongly correlated electronic and magnetic orders in molecular electronic solids and offers unique electro-magnetic phases with technological promises.

J Mol Histol ; 52(5): 975-989, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34100179


The morphological and possible functional interactions between the connective tissue and enamel organ cells were examined during the maturation phase of enamel formation, using immunohistochemical techniques. Decalcified mandibular sections (10 µm) including incisors were used from Wistar rats ages 10-12 weeks. Sections were incubated with one or two primary antibodies targeting cell cytoskeleton (vimentin, α-actin, α-tubulin), dendritic marker (OX6), gap junctions (cx-43), enzymes (nitric-oxide synthase (nos1) and cyclooxygenase (cox1)), and the ion transporters (Na+/H+ exchanger (NHE1) and Na+/Ca2+ exchanger (NCX)) for 24 h, before incubation with the appropriate conjugated fluorescent secondary antibodies. Sections were examined by fluorescence microscopy. Haematoxylin-eosin slides were also employed. Cellular heterogeneity and morphological modulations were identified within enamel organ cells and connective tissue covering suggesting complex cellular interactions and indicating a new functional concept and possible complementary role during enamel maturation. Also, some ion transportation activity, and nos1 and cox1 signalling pathways have been identified, indicating intercellular communication between these regions. A hypothesis is suggested, to explain the morphological modulation of ameloblasts and papillary cells during enamel maturation which functions to increase the transporting membrane surface area to accomplish faster and bulker ion transportation to achieve controlled pH and to direct Ca2+ towards enamel.

J Clin Med ; 9(9)2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32854206


BACKGROUND: the aim of this study was to assess the 2-year pulp survival of deep carious lesions in teeth excavated using a self-limiting protocol in a single-blind randomized controlled clinical trial. METHODS: At baseline, 101 teeth with deep carious lesions in 86 patients were excavated randomly using self-limiting or control protocols. Standardized clinical examination and periapical radiographs of teeth were performed after 1- and 2-year follow-ups (REC 14/LO/0880). RESULTS: During the 2-year period of the study, 24 teeth failed (16 and 8 at T12 and T24, respectively). Final analysis shows that 39/63 (61.9%) of teeth were deemed successful (16/33 (48.4%) and 23/30 (76.6%) in the control and experimental groups, respectively with a statistically significant difference (z score = 2.3, p = 0.021). Of teeth with severe and mild symptoms at T0, 42.9% and 36.7% respectively failed at T24 (p > 0.05). Within the self-limiting group, there was a lower success in premolars compared to molars (p < 0.05). CONCLUSION: after 2 years, there was a statistically significant higher pulp survival rate of teeth with deep carious lesions excavated using self-limiting protocols in patients with reversible pulpitis. Molars showed higher success than premolars in teeth excavated using the self-limiting protocol. There was no statistically significant association between the outcome and the severity of symptoms at T0 ( NCT03071588).

J Clin Exp Dent ; 11(8): e695-e700, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31598197


Background: This study aimed to evaluate the bond strength and the penetration depth of two adhesive systems to a new experimental semi-IPN fiber post versus a commercial post. Material and Methods: Experimental Kevlar fiber (KF) and control everStick®POST (ES) posts (n=20/ group) with a diameter of 1.5 mm were used, 10 posts coated with StickResin (SR) and the other 10 posts coated with Scotch bond multipurpose (SBMP) adhesives. Composite resin buildup was performed over each post, using a cylindrical plastic mold (10 mm × 6 mm). Four discs of 2 mm thickness were prepared from each post/composite buildup and underwent pushout bond strength test at a crosshead speed of 0.5 mm/min accompanied by failure mode analysis. A further three specimens from each subgroup were bonded with adhesives labeled with 0.1 wt% Rhodamine B and embedded in acrylic resin, sectioned and examined under a confocal Laser-scanning microscope (CLSM) to measure the depth of resin penetration. Statistical analysis included ANOVA and Tukey test, the significance level was assumed at a p-value less than 0.05. Results: The push-out bond strength of KF was comparable to that of ES with both SBMP and SR adhesives (P >0.05). Bond strength value for SBMP was higher than SR adhesive in either ES and KF posts with no significant difference (P > 0.05). ES exhibited higher adhesive penetration depth compared with KF (p<0.05). Conclusions: The bond strength of Kevlar post was comparable with the everStick post and the semi-interpenetrating structure of Kevlar post displayed some adhesive monomers diffusion indicating its usefulness as a new intracanal post. Key words:Kevlar fiber post, Bond strength, Penetration depth, Confocal, Semi-IPN polymer system.

J Egypt Natl Canc Inst ; 24(2): 71-6, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23582598


BACKGROUND: Nasolabial flaps have been recognised as versatile flaps for a variety of defects in the face, nose, lip and the oral cavity. Random pattern inferiorly based nasolabial flaps (NLF) have been utilised for covering small defects on the anterior floor of the mouth, but usually require a second stage procedure to divide the flap base. A subcutaneous pedicled inferiorly based nasolabial flap can provide a one stage repair of moderate sized defects of the floor of the mouth after de epithelialisation of the base of the flap. AIM: To evaluate the feasibility of a single stage reconstruction of intermediate sized defects in the oral cavity with an inferiorly based pedicled NLF. The study includes the indications of use of the flap, flap design, technique, and the complications rate. The incidence of secondary procedures and the final functional and the aesthetic results will also be evaluated. MATERIALS AND METHODS: A group of 20 patients presented with (T1-2) squamous cell carcinoma of the oral cavity have been treated at the Department of Surgery, National Cancer Institute, Cairo; in the period between January 2008 and September 2010. The pathology was confirmed with an incision biopsy and all metastatic work were carried out confirming that all patients were free from distant metastasis at presentation. Preoperative assessment also included assessment of the stage of the disease, the flap design and patient fitness for general anaesthesia. All patients underwent surgical excision combined with reconstruction of the defect with a subcutaneous inferiorly based pedicled NLF. The proximal part of the flap was routinely de epithelialised before it has been tunnelled through the cheek so a one stage procedure could only be required. RESULTS: The mean age of the patients was 62.3±6years, range (52-69years). All patients were diagnosed with squamous cell carcinoma. The anterior floor of the mouth constituted 40% of the defects, the lateral floor of the mouth 20% and the inner surface of the cheek 40%. There was no reported major complication; and only one patient suffered a reactionary haemorrhage that required re-exploration to secure the bleeder. A single procedure was adequate in most patients (80%), only 20% of patients required revision of the scar at the donor site or release of the tongue. The overall aesthetic results were either very satisfactory or satisfactory in the majority of patients (90%). Two patients were not satisfied with the final aesthetic results, one suffered from ectropion and the other had a donor site wound healing problem. The functional results (deglutition, speech) were satisfactory in most patients (70%), all were edentulous. CONCLUSION: An inferiorly based pedicled NLF is a reliable flap for the reconstruction of small and medium sized defects in the oral cavity. The flap can be best utilised for old edentulous and high risk patients where it can be used as a single stage procedure which is particularly useful in those types of patients. The flap can be safely combined with neck dissection even when the facial artery was ligated.

Carcinoma de Células Escamosas/cirurgia , Neoplasias Bucais/cirurgia , Boca/cirurgia , Sulco Nasogeniano , Retalhos Cirúrgicos , Idoso , Carcinoma de Células Escamosas/patologia , Bochecha/cirurgia , Feminino , Humanos , Lábio/cirurgia , Masculino , Pessoa de Meia-Idade , Boca/patologia , Neoplasias Bucais/patologia , Nariz/cirurgia , Procedimentos Cirúrgicos Bucais/métodos , Transplante de Pele , Cirurgia Plástica/métodos , Língua/cirurgia
J Egypt Soc Parasitol ; 39(1): 23-30, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19530607


Over four years (April 2004 to December 2008) 12 patients with blunt small bowel and mesenteric injuries were treated at three hospi-tals dealing with trauma. Ten cases were victims of traffic accidents, of whom 70% wore seat belts. There were 11 small bowel injuries (4 full-thickness & 7 seromuscular) and 9 mesenteric injuries (3 with & 6 without a de-vascularized bowel segment). All were managed initially following the Advanced Trauma Life Support (ATLS) guidelines. Emergency room ultrasound was positive for blood in 5/7 cases (71%) and CT scan in 2/4 (50%). Diagnostic peritoneal lavage (DPL) was performed in one case and was positive for blood.

Intestino Delgado/patologia , Mesentério/lesões , Traumatismos Abdominais , Acidentes de Trânsito , Adolescente , Adulto , Feminino , Humanos , Masculino , Mesentério/patologia , Pessoa de Meia-Idade , Ferimentos não Penetrantes , Adulto Jovem