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1.
Radiol Med ; 128(3): 357-361, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36752988

RESUMEN

PURPOSE: Stroke is a leading cause of long-term disability with high mortality rate in the first year after the event. In Campania, mechanical thrombectomy treatment significantly increases in the last 3 years, as well as hospitals delivering acute stroke treatments. The aim of this study is to demonstrate how a full opening of our stroke network improves stroke management and stroked patients' survival in Campania. MATERIAL AND METHODS: In Federico II University Hospital of Naples acting as a HUB center of 7 peripheral SPOKE hospitals in regional territory, 68 patients with acute ischemic stroke were evaluated with NIHSS and m-RS clinical scores and neuroradiological ASPECT scores, from January 1 to December 31, 2021. At hospital discharge, NIHSS score and three months after m-RS score were re-assessed to evaluate the therapeutic effects. RESULTS: Forty-two of 68 patients (63%) admitted to our hub center had ischemic acute stroke at CT evaluation; 29 patients had ASPECT score > 7 (69%), and 6 a score < 7 (14%). At admission, NIHSS score mean value was 10.75, and m-RS score mean value was 0.74. At discharge, NIHSS score mean value was 7.09. After three months, m-RS score mean value was 0.74. DISCUSSION: The inter-company agreement between Federico II University and several peripheral hospitals allows an absolute and relative increase in endovascular mechanical thrombectomy and intravenous thrombolysis procedures, with a relative prevalence of mechanical thrombectomy. A regional implementation of the stroke multi-disciplinary care system is hardly needed to ensure the optimum treatment for the largest number of patients, improving patient's outcome.


Asunto(s)
Isquemia Encefálica , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Trombectomía/métodos , Resultado del Tratamiento , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/cirugía , Hospitales , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/cirugía , Estudios Retrospectivos
2.
Gastroenterol Hepatol ; 46(9): 702-709, 2023 Nov.
Artículo en Inglés, Español | MEDLINE | ID: mdl-36716926

RESUMEN

BACKGROUND AND OBJECTIVE: The COVID-19 pandemic has been associated with a decrease in the colorectal cancer (CRC) incidence, due to the disruption of screening programmes and a downscaling of endoscopic activity. The endpoint of this study is to evaluate if the pandemic has led to a change in CRC diagnostic rate and presentation in our population. METHODS: Multicenter retrospective study of all public hospitals of the Aragon region, attending a population of 1,329,391 inhabitants. We have analyzed all CRC cases detected and endoscopic units workload the year before the pandemic onset (1 March 2019-14 March 2020) and the first year of the COVID-19 pandemic (15 March 2020-28 February 2021). RESULTS: The diagnosis of CRC cases dropped a 38.9% (888 pre-pandemic vs 542 pandemic cases). Also, there were 30.3% less colonoscopies performed (24,860 vs 17,337). During the pandemic, CRC cases were diagnosed in older patients (72.4±12.2 vs 71.2±12.1 years, p=0.021), and had more frequently severe complications at diagnosis (14.6% vs 10.4%, p=0.019). Moreover, most CRC cases were diagnosed in symptomatic patients (81.4%). No significant difference was found in CRC stage at diagnosis, although stage IV was more frequent (20.1% vs 16.1%). Most hospitals reported a lower workload of endoscopic activity. CONCLUSION: CRC diagnostic rate was lower after the onset of the pandemic. CRC was diagnosed in older patients and was more frequently associated with complications. After the onset of the pandemic, the endoscopic units did not reach the workload performed previously.


Asunto(s)
COVID-19 , Neoplasias Colorrectales , Humanos , Anciano , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/prevención & control , COVID-19/epidemiología , Pandemias , Estudios Retrospectivos , Colonoscopía , Detección Precoz del Cáncer , Prueba de COVID-19
3.
Int J Comput Dent ; 0(0): 0, 2023 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-37417446

RESUMEN

AIM: To determine the 3-year clinical and dimensional change of the soft tissue following implant placement in healed sites before and after loading with either customized or conventional healing abutments. MATERIALS AND METHODS: Premolar/molar implants were immediately loaded with either provisional and customized abutments without finishing lines according to principles of the Biologically Oriented Preparation Technique (BOPT), test group, or conventional healing abutments, control group. Three months later, the definitive crowns were fabricated. Primary outcomes (changes in the soft tissue) and secondary outcomes (adverse events) had been registered. RESULT: Fifty out of 87 subjects originally included were finally selected for this retrospective analysis: 23 in the test and 27 in the control group. During the first days after surgery 2 adverse events of mucositis, one for each group, occurred. A Few technical complications such as unscrewing 4 screw-retained crowns were recorded. A significant increase in the alveolar width was observed in both groups (test = +2.5±0.5mm, and control = +1.0±0.9mm). The widths appeared to not be merely changed from 3 months to 3 years in both groups. There were no significant differences regarding the width of the keratinized mucosa measured at baseline and after follow-up. Jemt papilla index showed a higher increase in the test group compared with that of the control group. CONCLUSION: Within 3 years of the follow-up period, peri-implant soft tissue outcomes of single, immediately loaded implants with customized healing abutments showed better results in terms of thickness and width when they were compared with those of the conventional group. Side effects count (mucositis and dehiscence) appeared to be very similar between the two groups. In addition, customized healing abutments led to significant augmentation of the alveolar width more than twice that registered in the conventional group.

4.
Dent Traumatol ; 37(5): 725-731, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33638228

RESUMEN

Traumatic dental injuries in elderly patients are a rising trend due to demographic and social changes of the population. Older dentulous patients in good health have become increasingly common. The development of a post-traumatic malocclusion is a common sequela resulting from mandibular condyle fracture, as in the case reported in this paper. The decision-making process led the authors to rule out conservative treatment options and to perform orthognathic surgery on an 81-year-old patient, an unprecedented report in the literature. At one-year follow-up, prophylactic therapy, a specific surgical technique, and osteotomy fixation have restored the occlusion to the pre-traumatic condition.


Asunto(s)
Maloclusión , Fracturas Mandibulares , Anciano , Anciano de 80 o más Años , Oclusión Dental , Humanos , Maloclusión/etiología , Mandíbula , Cóndilo Mandibular , Fracturas Mandibulares/diagnóstico por imagen , Fracturas Mandibulares/cirugía , Osteotomía
5.
BMC Oral Health ; 21(1): 100, 2021 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-33676469

RESUMEN

BACKGROUND: To introduce a theoretical solution to a posteriori describe the pose of a cylindrical dental fixture as appearing on radiographs; to experimentally validate the method described. METHODS: The pose of a conventional dental implant was described by a triplet of angles (phi-pitch, theta-roll, and psi-yaw) which was calculated throughout vector analysis. Radiographic- and simulated-image obtained with an algorithm were compared to test effectiveness, reproducibility, and accuracy of the method. The length of the dental implant as appearing on the simulated image was calculated by the trigonometric function and then compared with real length as it appeared on a two-dimensional radiograph. RESULTS: Twenty radiographs were analyzed for the present in silico and retrospective study. Among 40 fittings, 37 resulted as resolved with residuals ≤ 1 mm. Similar results were obtained for radiographic and simulated implants with absolute errors of - 1.1° ± 3.9° for phi; - 0.9° ± 4.1° for theta; 0° ± 1.1° for psi. The real and simulated length of the implants appeared to be heavily correlated. Linear dependence was verified by the results of the robust linear regression: 0.9757 (slope), + 0.1344 mm (intercept), and an adjusted coefficient of determination of 0.9054. CONCLUSIONS: The method allowed clinicians to calculate, a posteriori, a single real triplet of angles (phi, theta, psi) by analyzing a two-dimensional radiograph and to identify cases where standardization of repeated intraoral radiographies was not achieved. The a posteriori standardization of two-dimensional radiographs could allowed the clinicians to minimize the patient's exposure to ionizing radiations for the measurement of marginal bone levels around dental implants.


Asunto(s)
Implantes Dentales , Humanos , Imagenología Tridimensional , Radiografía , Estándares de Referencia , Reproducibilidad de los Resultados , Estudios Retrospectivos
6.
J Craniofac Surg ; 29(8): 2131-2134, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29944551

RESUMEN

PURPOSE: To investigate morbidity related to harversting of bilateral fibula free flap for head and neck reconstruction using subjective and functional tests. METHODS: Patients were retrospectively evaluated using point evaluation system (PES) and balance evaluation systems test (BESTest) questionnaires to assess morbidity related to surgery. RESULTS: Five patients were enrolled in the study. Mean PES scores was 22.2 over 24. Mean overall function assessed with BESTest was 77.6%, and the results were poorest for section I. Sections V and VI had scores of 88% and 83%, respectively, indicating that the sensory balance and gait stability of the patients were compromised only minimally. CONCLUSION: Bilateral harvesting of the fibula free flap is not associated with an increase in long-term morbidity and does not lead to significant functional impairments. Therefore, this procedure should be considered safe, and can be performed without concern regarding morbidity, when bone reconstruction with a fibula free flap is indicated.


Asunto(s)
Peroné/cirugía , Colgajos Tisulares Libres/efectos adversos , Reconstrucción Mandibular/efectos adversos , Complicaciones Posoperatorias/etiología , Recolección de Tejidos y Órganos/efectos adversos , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Morbilidad , Estudios Retrospectivos , Sitio Donante de Trasplante , Adulto Joven
7.
J Craniofac Surg ; 26(1): e44-8, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25569412

RESUMEN

The purpose of this study was to analyze a case of mandibular distraction in a case of Treacher Collins syndrome. Mandibular distraction is an adequate surgical treatment of patients with Pierre Robin sequence and represents an alternative to tracheostomy. In severe hypoplastic cases or when three-dimensional vector control or gonial angle control is necessary, extraoral bidirectional or multidirectional devices have an advantage over intraoral devices. The anchorage obtained with transfixing Kirschner wires fixed in the mandibular distal segment and symphysis is crucial in neonates for the stability of the devices. Moreover, with the use of a second pin for each bone segment, the extraoral devices allow to modify the vector orientation and consequently the shape of the newly formed mandible.


Asunto(s)
Mandíbula/cirugía , Disostosis Mandibulofacial/cirugía , Osteogénesis por Distracción/métodos , Clavos Ortopédicos , Hilos Ortopédicos , Diseño de Equipo , Fijadores Externos , Estudios de Seguimiento , Humanos , Recién Nacido , Masculino , Mandíbula/anomalías , Avance Mandibular/métodos , Cóndilo Mandibular/anomalías , Cóndilo Mandibular/cirugía , Reconstrucción Mandibular/métodos , Osteogénesis/fisiología , Osteogénesis por Distracción/instrumentación
8.
J Stomatol Oral Maxillofac Surg ; 124(6S): 101500, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37187242

RESUMEN

INTRODUCTION: The present study aimed to examine the middle-term effects of transcrestal double-sinus elevation (TSFE) versus alveolar/palatal split expansion technique (APS) and simultaneous implant placement in the augmented sinus. NULL HYPOTHESIS: there were no differences between groups. MATERIAL & METHODS: Magnetoelectric device was used for bone augmentation and expansion techniques in long-standing edentulous patients with a deficiency in vertical height in the posterior maxilla (3mm to 4mm residual bone height): TSFE group, or two-stage process with a first transcrestal sinus floor augmentation and a second sinus floor elevation with immediate implant placement; APS group, or "dual split and dislocation" of the two cortical bony plates towards the sinus and palatal side. Volumetric and linear analyses were performed on the superimposed preoperative and postoperative 3-year computed tomography scans. The level of significance was set at 0.05. RESULTS: Thirty patients were selected for the present analysis. For both groups significant differences were found in the volume outcomes between baseline and 3-year follow-up, showing a gain of about +0.28±0.06cm3 for the TSFE group, and +0.43±0.12cm3 for the APS group, with p-values < 0.0001. However, an effective increase of the volume of the alveolar crest was registered just in the APS group (+0.22±0.09cm3). A significant increase in bone width was found in the APS group (+1.45±0.56mm with p-value < 0.0001); on the contrary, a slight width reduction of the alveolar crest was observed in the TSFE group (-0.63±0.21mm). DISCUSSION: TSFE procedure seemed to not affect the shape of the alveolar crest. APS procedures led to a higher increase of the volume available for dental implant placement and could be used in horizontal bone defects too.


Asunto(s)
Implantes Dentales , Elevación del Piso del Seno Maxilar , Humanos , Implantación Dental Endoósea/métodos , Elevación del Piso del Seno Maxilar/métodos , Estudios Retrospectivos , Seno Maxilar/diagnóstico por imagen , Seno Maxilar/cirugía , Proceso Alveolar/diagnóstico por imagen , Proceso Alveolar/cirugía
9.
Int J Periodontics Restorative Dent ; 43(4): e165-e172, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37552194

RESUMEN

Adequate implant primary stability is a key factor to obtain osseointegration and can be measured at insertion by insertion torque (IT) and at different timepoints with resonance frequency analysis (RFA), expressed as an implant stability quotient (ISQ). This retrospective study investigated the correlation between ISQ and IT at implant insertion. All patients who were eligible for this single-cohort retrospective clinical trial were treated with an immediate implant. IT parameters were recorded at implant insertion, and ISQ values were recorded at insertion and at 2-, 4-, and 12-month follow-ups. The study comprised 23 patients who received 32 implants. The mean IT value was 46.87 ± 9.66 Ncm (range: 25 to 65 Ncm), and the mean ISQ value at implant insertion was 71.45 ± 4.24 (range: 63 to 78); these values showed a statistically significant correlation (P < .0001). According to the present data and considering the implant design used in this trial, there is a statistically significant and positive correlation between IT and ISQ values. Thus, ISQ can be used as a reliable method to measure implant stability over time.


Asunto(s)
Implantación Dental Endoósea , Implantes Dentales , Humanos , Implantación Dental Endoósea/métodos , Retención de Prótesis Dentales , Oseointegración , Análisis de Frecuencia de Resonancia , Estudios Retrospectivos , Torque
10.
Int J Oral Maxillofac Implants ; 37(5): 920-928, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36170306

RESUMEN

PURPOSE: To examine the short-term outcomes of maxillary sinus augmentations consisting of laterally and apically displacing the palatal wall through a transcrestal approach. MATERIALS AND METHODS: The maxillary sinus floor was fractured in its palatal aspect by allowing a displacement in the buccal and apical direction with a magnetoelectric system. A medial displacement of the alveolar crest in its palatal bony plate was performed at the same time. Crestal bone change was investigated using superimposed preoperative and postsurgical computed tomography scans. Clinical and radiologic outcomes over 1 year were evaluated. RESULTS: A total of 18 implants were selected for retrospective volumetric and linear analyses. Sinus floor and alveolar bone augmentation surgery led to a significant increase in the bone volume (P = .0002) from 0.134 ± 0.060 cm3 to 0.639 ± 0.166 cm3, with an overall gain of +0.504 ± 0.139 cm3. No part of the implant apices appeared to protrude into the maxillary sinus at the 1-year follow-up. The width of the alveolar crest changed from 5.1 ± 0.5 mm to 6.5 ± 0.7 mm, with a significant increase of +1.4 ± 0.6 mm registered at 1 year. However, a marginal bone loss of 1.0 ± 0.8 mm was observed. When tooth positions were investigated, no significant differences between the two groups (premolars versus molars) were found. CONCLUSION: Significant and effective bone gains allowed proper placement of the dental implants but with a minimal loss of peri-implant bone volume.


Asunto(s)
Implantes Dentales , Elevación del Piso del Seno Maxilar , Implantación Dental Endoósea/métodos , Maxilar/cirugía , Seno Maxilar/diagnóstico por imagen , Seno Maxilar/cirugía , Estudios Retrospectivos , Elevación del Piso del Seno Maxilar/métodos , Tomografía Computarizada por Rayos X
11.
Chem Sci ; 12(23): 8048-8057, 2021 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-34194694

RESUMEN

The presence of non-hexagonal rings in the honeycomb carbon arrangement of graphene produces rippled graphene layers with valuable chemical and physical properties. In principle, a bottom-up approach to introducing distortion from planarity of a graphene sheet can be achieved by careful insertion of curved polyaromatic hydrocarbons during the growth of the lattice. Corannulene, the archetype of such non-planar polyaromatic hydrocarbons, can act as an ideal wrinkling motif in 2D carbon nanostructures. Herein we report an electrochemical bottom-up method to obtain egg-box shaped nanographene structures through a polycondensation of corannulene that produces a new conducting layered material. Characterization of this new polymeric material by electrochemistry, spectroscopy, electron microscopy (SEM and TEM), scanning probe microscopy, and laser desorption-ionization time of flight mass spectrometry provides strong evidence that the anodic polymerization of corannulene, combined with electrochemically induced oxidative cyclodehydrogenations (Scholl reactions), leads to polycorannulene with a wavy graphene-like structure.

12.
Oral Maxillofac Surg ; 25(1): 75-79, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32809161

RESUMEN

BACKGROUND: Harmonic instruments are becoming popular in head and neck surgeries. In this prospective, randomized study, the efficacy of the harmonic instruments and electrosurgical technique is compared. MATERIALS AND METHODS: A total of 48 patients undergoing unilateral neck dissection were divided into two groups. In one group, surgery was performed using conventional hemostatic instruments while in the other, only harmonic instruments were used. The two techniques were then compared with regard to intra- and post-operative blood loss, complications in operating time, drain, tracheotomy and nasogastric tube duration, and post-operative hospital stay. RESULTS: Differences in operative time (P = 0.647), total suction drainage (P = 0.362) and time that drains (P = 0.404), nasogastric tube (P = 0.378), and tracheotomy (P = 0.052) were kept in place and proved not significant. The average blood loss during surgery was significantly greater in the CH group (P = 0.003) as the number of hemoclips and resorbable ligature used (P = 0.002). CONCLUSIONS: In contrast to what has been reported up to now, our study did not reveal a net advantage in the use of harmonic instruments with respect to classical instruments in terms of surgical outcome. On the contrary, harmonic tools had a higher complication rate (i.e., salivary fistula and lymphatic leak) probably due to the decreased ability of this instruments to permanently close glandular structures and lymphatic ducts. In these cases, a closure technique such as electrocautery or classic knot-tying should be used.


Asunto(s)
Electrocoagulación , Disección del Cuello , Humanos , Tempo Operativo , Estudios Prospectivos , Instrumentos Quirúrgicos
13.
Horm Behav ; 56(1): 93-100, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19324045

RESUMEN

Early-life environmental events can induce profound long-lasting changes in several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces stress responses and sexual behavior in adult rats. The purpose of this study was to analyze the effects of neonatal handling on social behaviors of male and female rats in adulthood, as manifest by the results of social memory and social interaction tests. The number of oxytocin (OT) and vasopressin (VP) neurons in the paraventricular (PVN) and supraoptic (SON) nuclei of hypothalamus were also analyzed. The results did not demonstrate impairment of social memory. Notwithstanding, handling did reduce social investigative interaction and increase aggressive behavior in males, but did not do so in females. Furthermore, in both males and females, handling was linked with reduced number of OT-neurons in the parvocellular region of the PVN, while no differences were detected in the magnocellular PVN or the SON. On the other hand, handled males exhibited increased number of VP-neurons in the magnocellular zone of the PVN. We may conclude that the repeated brief maternal separations can reduce affiliative social behavior in adult male rats. Moreover, the disruption of the mother-infant relationship caused by the handling procedure induced long-lasting morphological changes in critical neuroendocrine areas that are involved in social bonding in mammals.


Asunto(s)
Memoria , Neuronas/metabolismo , Oxitocina/metabolismo , Conducta Social , Estrés Psicológico/fisiopatología , Vasopresinas/metabolismo , Análisis de Varianza , Animales , Animales Recién Nacidos , Femenino , Inmunohistoquímica , Masculino , Privación Materna , Núcleo Hipotalámico Paraventricular/crecimiento & desarrollo , Núcleo Hipotalámico Paraventricular/metabolismo , Ratas , Ratas Wistar , Caracteres Sexuales , Núcleo Supraóptico/crecimiento & desarrollo , Núcleo Supraóptico/metabolismo
14.
J Phys Chem B ; 113(7): 1954-62, 2009 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-19173564

RESUMEN

The voltammetric generation of corannulene anions was investigated over a large range of experimental conditions comprising either "traditional" electrochemical solvents, such as dimethylformamide, acetonitrile, and tetrahydrofuran, or "unconventional" solvents, such as liquid ammonia, liquid methylamine, or liquid dimethylamine, and several different supporting electrolytes. Strong ion pairing effects were found to dominate the electrochemical generation of corannulene higher anions, and through the suitable choice of the solvent/electrolyte system, we observed, for the first time, the reversible electrochemical generation of up to the triply reduced corannulene. The standard potentials obtained experimentally compared rather well with the theoretical values calculated by ab initio and density functional methods, in which solvation and ion pairing effect were explicitly taken into account. In particular, the calculations considered the effect of the electrolyte cation size on ion pairing in order to rationalize the occurrence of the third reduction within the experimental potential window.


Asunto(s)
Simulación por Computador , Modelos Químicos , Hidrocarburos Policíclicos Aromáticos/química , Electroquímica , Oxidación-Reducción
15.
Org Biomol Chem ; 7(11): 2402-13, 2009 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-19462051

RESUMEN

Novel 5,15-bis(9-anthracenyl)porphyrin derivatives (, ) were synthesized by stepwise Suzuki-type coupling reactions using anthracenyl-boronates bearing various electronically active moieties. Absorption spectra of these porphyrin conjugates reveal some degree of delocalisation with the directly linked chromophores, particularly in the case of anthracenyl-porphyrin bearing dimethylanilino moieties at the two extremities. Fluorescence and 77 K phosphorescence properties indicate that the excitation energy is invariably funnelled to the lowest singlet and triplet states of the porphyrin chromophore. The latter levels have been probed also by transient absorption spectroscopy, showing the typical triplet features detected in meso-substituted porphyrins. Extensive electrochemical studies have been performed to unravel the electronic properties of the newly synthesized porphyrins. Low-temperature cyclic voltammetry investigations showed that the anthracenyl-porphyrins are capable of undergoing as many as four electron transfer processes. In particular, by means of UV-Vis-NIR spectroelectrochemical measurements, a NIR-centred intramolecular photoinduced intervalence charge transfer (IV-CT) from a neutral N,N-dimethylanilino moiety to the N,N-dimethylanilino radical cation has been observed for the doubly-oxidised porphyrin (2+). The molecules also showed unexpected electrogenerated chemiluminescence properties, which revealed to be largely controlled by the electronic characteristics of the peripheral anthracenyl substituents. The structural and the electronic properties of these complexes have been also characterised by DFT calculations, as well as by X-ray crystallographic analyses.


Asunto(s)
Antracenos/química , Luminiscencia , Porfirinas/química , Antracenos/síntesis química , Simulación por Computador , Cristalografía por Rayos X , Electroquímica , Modelos Moleculares , Estructura Molecular , Procesos Fotoquímicos , Porfirinas/síntesis química , Teoría Cuántica , Espectrofotometría
16.
J Am Chem Soc ; 130(12): 3788-96, 2008 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-18314972

RESUMEN

The formidable electron-acceptor properties of C60 contrast with its difficult oxidations. Only recently it has become possible to achieve reversibility of more than one electrochemical anodic process versus the six reversible cathodic reductions. Here we exploit the reactivity of electrochemical oxidations of pure C60 to grow a film of high thermal and mechanical stability on the anode. The new material differs remarkably from its precursor since it conducts both electrons and holes. Its growth and properties are consistently characterized by a host of techniques that include atomic force microscopy (AFM), Raman and infrared spectroscopies, X-ray-photoelectron spectroscopy (XPS), secondary-ion mass spectrometry (SIMS), scanning electron microscopy and energy-dispersive X-ray analysis (SEM-EDX), matrix-assisted laser desorption/ionization (MALDI), and a variety of electrochemical measurements.


Asunto(s)
Fulerenos/química , Membranas Artificiales , Cationes/química , Electroquímica , Electrodos , Microscopía Electrónica de Rastreo , Oxidación-Reducción , Tamaño de la Partícula , Platino (Metal)/química , Espectrometría de Masa de Ion Secundario , Análisis Espectral , Propiedades de Superficie , Rayos X
17.
J Am Chem Soc ; 130(8): 2593-601, 2008 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-18251541

RESUMEN

Although the desirability of developing synthetic molecular machine systems that can function on surfaces is widely recognized, to date the only well-characterized examples of electrochemically switchable rotaxane-based molecular shuttles which can do so are based on the tetracationic viologen macrocycle pioneered by Stoddart. Here, we report on a [2]rotaxane which features succinamide and naphthalene diimide hydrogen-bonding stations for a benzylic amide macrocycle that can shuttle and switch its net position both in solution and in a monolayer. Three oxidation states of the naphthalene diimide unit can be accessed electrochemically in solution, each one with a different binding affinity for the macrocycle and, hence, corresponding to a different distribution of the rings between the two stations in the molecular shuttle. Cyclic voltammetry experiments show the switching to be both reversible and cyclable and allow quantification of the translational isomer ratios (thermodynamics) and shuttling dynamics (kinetics) for their interconversion in each state. Overall, the binding affinity of the naphthalene diimide station can be changed by 6 orders of magnitude over the three states. Unlike previous electrochemically active amide-based molecular shuttles, the reduction potential of the naphthalene diimide unit is sufficiently positive (-0.68 V) for the process to be compatible with operation in self-assembled monolayers on gold. Incorporating pyridine units into the macrocycle allowed attachment of the shuttles to an acid-terminated self-assembled monolayer of alkane thiols on gold. The molecular shuttle monolayers were characterized by X-ray photoelectron spectroscopy and their electrochemical behavior probed by electrochemical impedance spectroscopy and double-potential step chronoamperometry, which demonstrated that the redox-switched shuttling was maintained in this environment, occurring on the millisecond time scale.

18.
Brain Dev ; 30(6): 391-5, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18180123

RESUMEN

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are degenerative disorders of muscle. Although the mechanisms underlying muscle degeneration are still uncertain, oxidative-damage has been proposed to play a key role. Isoprostanes are markers of free radical-catalyzed lipid peroxidation; the aim of our study was to evaluate plasma isoprostane levels in group of patients affected by Duchenne and Becker muscular dystrophies. PF(2)-isoprostane levels were measured by colorimetric enzyme immunoassay in the plasma of 17 patients with DMD and 24 with BMD. When compared to a group of healthy controls, affected patients showed significantly higher plasma levels of isoprostanes (p=0.001). When patients were stratified according to the clinical diagnosis, isoprostane levels were not statistically different between DMD and BMD patients. In conclusion whether the condition of oxidative stress found in plasma depends on the degenerative process occurring in muscles or on different mechanisms, such as the release of myoglobin in the blood, should be ascertained. However, our study confirms that oxidative stress findings in DMD/BMD patients are effectively present at the plasma levels. The condition of oxidative stress might act as an adjunctive cause of extra-muscular cell damage to which these patients are exposed for their entire life.


Asunto(s)
Isoprostanos/sangre , Distrofia Muscular de Duchenne/sangre , Estrés Oxidativo/fisiología , Adolescente , Adulto , Análisis de Varianza , Niño , Preescolar , Femenino , Humanos , Masculino
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