RESUMEN
Edge functionalization of bottom-up synthesized graphene nanoribbons (GNRs) with anthraquinone and naphthalene/perylene monoimide units has been achieved through a Suzuki coupling of polyphenylene precursors bearing bromo groups, prior to the intramolecular oxidative cyclo-dehydrogenation. High efficiency of the substitution has been validated by MALDI-TOF MS analysis of the functionalized precursors and FT-IR, Raman, and XPS analyses of the resulting GNRs. Moreover, AFM measurements demonstrated the modulation of the self-assembling behavior of the edge-functionalized GNRs, revealing that GNR-PMI formed an intriguing rectangular network. This result suggests the possibility of programming the supramolecular architecture of GNRs by tuning the functional units.
RESUMEN
Structurally well-defined graphene nanoribbons (GNRs) have attracted great interest as next-generation semiconductor materials. The functionalization of GNRs with polymeric side chains, which can widely broaden GNR-related studies on physiochemical properties and potential applications, has remained unexplored. Here, we demonstrate the bottom-up solution synthesis of defect-free GNRs grafted with flexible poly(ethylene oxide) (PEO) chains. The GNR backbones possess an armchair edge structure with a width of 1.0-1.7 nm and mean lengths of 15-60 nm, enabling near-infrared absorption and a low bandgap of 1.3 eV. Remarkably, the PEO grafting renders the GNRs superb dispersibility in common organic solvents, with a record concentration of â¼1 mg mL(-1) (for GNR backbone) that is much higher than that (<0.01 mg mL(-1)) of reported GNRs. Moreover, the PEO-functionalized GNRs can be readily dispersed in water, accompanying with supramolecular helical nanowire formation. Scanning probe microscopy reveals raft-like self-assembled monolayers of uniform GNRs on graphite substrates. Thin-film-based field-effect transistors (FETs) of the GNRs exhibit a high carrier mobility of â¼0.3 cm(2) V(-1) s(-1), manifesting promising application of the polymer-functionalized GNRs in electronic devices.
RESUMEN
In this paper, we report on two fast and non-destructive methods for nanostructured film density evaluation based on a combination of energy dispersive x-ray spectroscopy for areal density measurement and scanning electron microscopy (SEM) for thickness evaluation. These techniques have been applied to films with density ranging from the density of a solid down to a few [Formula: see text], with different compositions and morphologies. The high resolution of an electron microprobe has been exploited to characterize non-uniform films both at the macroscopic scale and at the microscopic scale.
Asunto(s)
Uñas/patología , Onicomicosis/epidemiología , Onicomicosis/patología , Psoriasis/complicaciones , Adolescente , Adulto , Anciano , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Retroperitoneal great vessel injuries are a rare but dramatic complication of any minimally invasive procedure. We report a case of laceration of the anterior aspect of the inferior vena cava following insertion of the Verress needle during a laparoscopic cholecystectomy. A 32-year-old man was operated on for acute cholecystitis. During the insertion of the Verress needle, a laceration of the anterior aspect of the inferior vena cava occurred. Immediate conversion and suture of the vessel were performed. The patient did well and was discharged after 24 days because of postoperative pancreatitis, managed with medical therapy. Major vascular injuries during laparoscopic procedures are rare but catastrophic complications which may endanger the patient's life. Over 75% of these lesions occur during insertion of the Verress needle or the Hasson trocar. Prompt diagnosis and immediate conversion are mandatory for correct management of these injuries so as to minimise morbidity and mortality.
Asunto(s)
Colecistectomía/métodos , Complicaciones Intraoperatorias/etiología , Laparoscopía , Vena Cava Inferior/lesiones , Adulto , Humanos , MasculinoRESUMEN
The metabolic changes associated with diabetes mellitus (DM) affect a variety of organs and systems, including the skin. Skin lesions are frequently observed in patients with DM, resulting from a complex interaction among biochemical, vascular, immune, and metabolic changes. Cutaneous manifestations may develop at any time in the course of DM. They can be the first sign of the disease, possibly helping in diagnosis, or represent a marker of poor glycemic control. Given the high prevalence of cutaneous manifestations in DM, their possible role in favoring DM early diagnosis, and their relationship with the patient's metabolic control, a group of Italian dermatologists and diabetologists, the DiaDex expert group, jointly formulated a few basic statements aimed at favoring a stricter interdisciplinary cooperation in order to improve patients' management. Deeper knowledge of the skin lesions most commonly associated with DM, their early identification, and prompt reciprocal referral, when appropriate, are the pivotal points of these statements and should represent the pillars of such desired cooperation. The dermatologists and diabetologists of the DiaDex group believe that their different diagnostic and therapeutic skills put together may significantly benefit the many DM patients with cutaneous complications and hope that this paper may provide some guidance on how to achieve this goal.