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1.
Small ; : e2004615, 2020 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-33090693

RESUMEN

The understanding of living systems and their building blocks relies on the assessment of structure-function relationships at the nanoscale. Although electron microscopy (EM) gives access to ultrastructural imaging with nanometric resolution, the unambiguous localization of specific molecules is challenging. An EM approach capable of localizing biomolecules with respect to the cellular ultrastructure will offer a direct route to the molecular blueprints of biological systems. In an approach departing from conventional correlative imaging, an electron beam may be used as excitation source to generate optical emission with nanometric resolution, that is, cathodoluminescence (CL). Once suitable luminescent labels become available, CL may be harnessed to enable identification of biomolecule labels based on spectral signatures rather than electron density and size. This work presents CL-enabled immunolabeling based on rare-earth element doped nanoparticle-labels allowing specific molecules to be visualized at nanoscale resolution in the context of the cellular ultrastructure. Folic acid decorated nanoparticles exhibiting single particle CL emission are employed to specifically label receptors and identify characteristic receptor clustering on the surface of cancer cells. This demonstration of CL immunotargeting gives access to protein localization in the context of the cellular ultrastructure and paves the way for immunolabeling of multiple proteins in EM.

2.
Nano Lett ; 19(9): 6013-6018, 2019 09 11.
Artículo en Inglés | MEDLINE | ID: mdl-31373824

RESUMEN

The mechanistic understanding of structure-function relationships in biological systems heavily relies on imaging. While fluorescence microscopy allows the study of specific proteins following their labeling with fluorophores, electron microscopy enables holistic ultrastructural analysis based on differences in electron density. To identify specific proteins in electron microscopy, immunogold labeling has become the method of choice. However, the distinction of immunogold-based protein labels from naturally occurring electron dense granules and the identification of several different proteins in the same sample remain challenging. Correlative cathodoluminescence electron microscopy (CCLEM) bioimaging has recently been suggested to provide an attractive alternative based on labels emitting characteristic light. While luminescence excitation by an electron beam enables subdiffraction imaging, structural damage to the sample by high-energy electrons has been identified as a potential obstacle. Here, we investigate the feasibility of various commonly used luminescent labels for CCLEM bioimaging. We demonstrate that organic fluorophores and semiconductor quantum dots suffer from a considerable loss of emission intensity, even when using moderate beam voltages (2 kV) and currents (0.4 nA). Rare-earth element-doped nanocrystals, in particular Y2O3:Tb3+ and YVO4:Bi3+,Eu3+ nanoparticles with green and orange-red emission, respectively, feature remarkably high brightness and stability in the CCLEM bioimaging setting. We further illustrate how these nanocrystals can be readily differentiated from morphologically similar naturally occurring dense granules based on optical emission, making them attractive nanoparticle core materials for molecular labeling and (multi)color CCLEM.


Asunto(s)
Sustancias Luminiscentes/química , Microscopía Electrónica , Imagen Molecular , Puntos Cuánticos/química , Luminiscencia , Mediciones Luminiscentes , Metales de Tierras Raras/química , Nanopartículas/química , Difracción de Rayos X
3.
Sci Technol Adv Mater ; 20(1): 173-186, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30891104

RESUMEN

We present a methodology to accelerate and estimate the lifetime of an interlayer under dynamic loading in body-like media. It is based on accelerating corrosion fatigue processes taking place at the buried interface of a Si-based adhesion-promoting interlayer in articulating implants on a CoCrMo biomedical alloy; the implants are coated with diamond-like carbon (DLC). The number of interface loading cycles to delamination is determined by reciprocal loading in corrosive fluid. Its dependence on the load is summarized in a Wöhler-like curve of a DLC/DLC-Si/CoCrMo system in body working conditions: cyclic stresses at 37 °C in phosphate buffered saline (PBS). The presence of oxygen as a contaminant strongly affects the lifetime of the interface under corrosion fatigue. The main parameters acting on the prediction, with a special emphasis on simulated in vivo conditions, are analyzed and discussed: the media (PBS, Milli-Q water, NaCl, Ringers' solution and bovine calf serum), the load, the frequency and the composition of the interface determined by X-ray photoelectron spectroscopy.

4.
Childs Nerv Syst ; 32(12): 2459-2464, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27406558

RESUMEN

PURPOSE: Optimal management of extracranial carotid artery dissections (eCAD) in pediatric patients is not well documented, and endovascular interventions are rarely reported. METHODS: A 10-year-old girl sustained multiple systemic injuries in a motor vehicle accident, including an eCAD with pseudoaneurysm. She initially failed both aspirin and endovascular stenting with progressive enlargement of a traumatic cervical carotid pseudoaneurysm and stenosis. RESULTS: Second-stage endovascular stent placement with coiling resulted in successful occlusion of the pseudoaneurysm. At 30-month imaging follow-up, the parent vessel remained patent with no evidence of the pseudoaneurysm. CONCLUSION: In the setting of poly-trauma, management of eCAD can be complex especially in the pediatric population. There is little data on the endovascular treatment of eCAD in children. Failed endovascular therapies are extremely rare. Our report supports surveillance imaging as repeat endovascular treatment may be necessary.


Asunto(s)
Traumatismos de las Arterias Carótidas/cirugía , Disección de la Arteria Carótida Interna/cirugía , Procedimientos Endovasculares/métodos , Accidentes de Tránsito , Niño , Embolización Terapéutica/métodos , Femenino , Humanos
5.
Neurocrit Care ; 24(1): 6-46, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26714677

RESUMEN

BACKGROUND: The use of antithrombotic agents, including anticoagulants, antiplatelet agents, and thrombolytics has increased over the last decade and is expected to continue to rise. Although antithrombotic-associated intracranial hemorrhage can be devastating, rapid reversal of coagulopathy may help limit hematoma expansion and improve outcomes. METHODS: The Neurocritical Care Society, in conjunction with the Society of Critical Care Medicine, organized an international, multi-institutional committee with expertise in neurocritical care, neurology, neurosurgery, stroke, hematology, hemato-pathology, emergency medicine, pharmacy, nursing, and guideline development to evaluate the literature and develop an evidence-based practice guideline. Formalized literature searches were conducted, and studies meeting the criteria established by the committee were evaluated. RESULTS: Utilizing the GRADE methodology, the committee developed recommendations for reversal of vitamin K antagonists, direct factor Xa antagonists, direct thrombin inhibitors, unfractionated heparin, low-molecular weight heparin, heparinoids, pentasaccharides, thrombolytics, and antiplatelet agents in the setting of intracranial hemorrhage. CONCLUSIONS: This guideline provides timely, evidence-based reversal strategies to assist practitioners in the care of patients with antithrombotic-associated intracranial hemorrhage.


Asunto(s)
Cuidados Críticos/normas , Fibrinolíticos/administración & dosificación , Fibrinolíticos/efectos adversos , Hemorragias Intracraneales/inducido químicamente , Hemorragias Intracraneales/tratamiento farmacológico , Neurología/normas , Guías de Práctica Clínica como Asunto/normas , Sociedades Médicas/normas , Humanos
6.
Chin J Physiol ; 59(5): 276-283, 2016 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-27604138

RESUMEN

The performance and sex differences of long-distance triathletes competing in 'Ironman Hawaii' are well investigated. However, less information is available with regards to triathlon races of the Ironman distance held under extreme environmental conditions (e.g. extreme cold) such as the 'Isklar Norseman Xtreme Triathlon' which started in 2003. In 'Isklar Norseman Xtreme Triathlon', athletes swim at a water temperature of ~13-15°C, cycle at temperatures of ~5-20°C and run at temperatures of ~12-28°C in the valley and of ~2-12°C at Mt. Gaustatoppen. This study analysed the performance trends and sex differences in 'Isklar Norseman Xtreme Triathlon' held from 2003 to 2015 using mixed-effects regression analyses. During this period, a total of 175 women (10.6%) and 1,852 men (89.4%) successfully finished the race. The number of female (r² = 0.53, P = 0.0049) and male (r² = 0.37, P = 0.0271) finishers increased and the men-to-women ratio decreased (r² = 0.86, P < 0.0001). Men were faster than women in cycling (25.41 ± 2.84 km/h versus 24.25 ± 2.17 km/h) (P < 0.001), but not in swimming (3.06 ± 0.62 km/h vs. 2.94 ± 0.57 km/h), running (7.43 ± 1.13 km/h vs. 7.31 ± 0.93 km/h) and overall race time (874.57 ± 100.62 min vs. 899.95 ± 90.90 min) (P > 0.05). Across years, women improved in swimming and both women and men improved in cycling and in overall race time (P < 0.001). In running, however, neither women nor men improved (P > 0.05). In summary, in 'Isklar Norseman Xtreme Triathlon' from 2003 to 2015, the number of successful women increased across years, women achieved a similar performance to men in swimming, cycling and overall race time, and women improved across years in swimming, cycling and overall race time.


Asunto(s)
Rendimiento Atlético/estadística & datos numéricos , Caracteres Sexuales , Femenino , Humanos , Masculino
7.
Ther Umsch ; 72(5): 343-55, 2015 May.
Artículo en Alemán | MEDLINE | ID: mdl-26098073

RESUMEN

Running can be performed as a sprint discipline on the track over a few meters up to 10 km to the marathon and ultramarathon running distances over hundreds to thousands of kilometers. Running performance is influenced by a variety of anthropometric and training factors. Morphological features such as skin fold thickness, body fat percentage, circumferences and length of limbs, body weight, body height and body mass index (BMI) seem to have an influence on the running performance. The training volume and running speed during training are also correlated with running performance. When all variables were investigated comparatively, body fat and running speed during training were usually the most important influencing factors. For longer running performances (over 6 hours or 100 km, respectively), the aspects of experience (number of successfully finished races) and personal best times were, however, far more important than training volume or morphological characteristics such as body fat. It was also shown that ultra runners prepare differently (lower running speed and higher running volume) as runners competing over shorter distances such as half-marathon and marathon.


Asunto(s)
Antropometría , Rendimiento Atlético , Composición Corporal , Constitución Corporal , Educación y Entrenamiento Físico , Carrera , Adulto , Índice de Masa Corporal , Femenino , Humanos , Masculino , Suiza
8.
Childs Nerv Syst ; 30(5): 937-43, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24212331

RESUMEN

PURPOSE: Literature on the endovascular treatment of occlusive acute ischemic stroke (AIS) in the pediatric population remains nebulous. Clinical trials evaluating the role of systemic and intra-arterial thrombolysis, and mechanical thrombectomy have been strictly isolated to the adult population and largely unknown in their safety and efficacy in the pediatric group. METHODS: The authors present a review of the literature and their own two cases of occlusive acute ischemic stroke in children younger than the age of 10 years who were treated with modern endovascular devices, specifically with stent retrievers, and discuss their clinical and technical considerations as well as their limitations. RESULTS: In both pediatric patients, a combination of stent retriever and Penumbra aspiration were used to achieve Thrombolysis In Cerebral Infarction (TICI) 2a or greater with reduction of overall stroke burden. A reduction of National Institutes of Health Stroke Scale (NIHSS) of 8 or greater was achieved at discharge. At 3-month follow-up, the patients had a NIHSS of 6 and 2, respectively. One patient continued to improve from NIHSS of 6 to 3 at 6 months. CONCLUSION: In carefully, selected pediatric patients, modern endovascular techniques may be used to treat occlusive pediatric AIS. However, larger clinical trials are needed to evaluate the overall safety and effectiveness.


Asunto(s)
Procedimientos Endovasculares/métodos , Accidente Cerebrovascular/cirugía , Isquemia Encefálica/complicaciones , Angiografía Cerebral , Niño , Femenino , Fibrinolíticos/uso terapéutico , Humanos , Masculino , Accidente Cerebrovascular/etiología , Tomógrafos Computarizados por Rayos X , Resultado del Tratamiento
9.
Int J Mol Sci ; 15(6): 10527-40, 2014 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-24921709

RESUMEN

Diamond like carbon (DLC) coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD) process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution up to a maximum of 101 million articulation cycles with an amplitude of ±2° and -3/+6° in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES) and cross section scanning electron microscopy (SEM) analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen), limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the α-ß tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD). It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs. ceramic.


Asunto(s)
Carbono/química , Diamante/química , Sustitutos de Huesos/química , Corrosión , Humanos , Ensayo de Materiales , Prótesis e Implantes , Propiedades de Superficie , Tantalio/química , Vitalio/química
10.
Surg Neurol Int ; 15: 127, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38742006

RESUMEN

Background: Transcarotid artery revascularization (TCAR) is becoming an increasingly popular treatment of carotid stenosis. Despite this rapid adoption, little in the literature describes the associated complications of this procedure. Case Description: We report a case of a left M1 large-vessel occlusion following treatment of symptomatic, high-grade carotid stenosis with a TCAR procedure approximately three weeks earlier. The initial angiography demonstrated a pseudoaneurysm in the left common carotid artery at the site of TCAR access with a distal clot in the carotid stent. The clot within the stent was aspirated, and a mechanical thrombectomy was performed with a combination of a stent-retriever and aspiration catheter for thrombolysis in cerebral infarction 2B revascularization. Conclusion: The TCAR procedure offers a novel method for revascularization of carotid lesions; it does include its complications. While generally safe, access site complications such as pseudoaneurysms can always occur. Knowledge of this risk allows for appropriate surveillance and management should it occur.

11.
Eur Heart J Case Rep ; 8(5): ytae202, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38711684

RESUMEN

Background: Marathon running poses unique cardiovascular challenges, sometimes leading to syncopal episodes. We present a case series of athletes who experienced pre-/syncope during the Zurich Marathon 2023, accompanied by elevated cardiac biomarkers. Case summary: Eight athletes (2 females, 6 males) aged 21-35 years, with pre-/syncope and various additional diverse symptoms such as dizziness and palpitations during the (half-)marathon, were admitted to two emergency departments in Zurich, Switzerland. Clinical evaluations included electrocardiogram, echocardiography, telemetry, coronary computed tomography (CT) scans, and cardiac biomarker assessments. High-sensitive troponin T (hs-cTnT) was elevated in all cases at initial assessment and returned to normal at follow-up. All athletes who received CT scans had normal coronary and brain CT results. None of the eight athletes had underlying cardiovascular disease. Renal function normalized post-admission, and neurological symptoms resolved within hours. Creatinine levels indicated transient acute kidney injury. A common feature was inexperience in running, inadequate race preparation, particularly regarding fluid, electrolyte, and carbohydrate intake, along with pacing issues and lack of coping strategies with heat. Discussion: From a clinician perspective, the case series highlights the challenge in the management of patients with a pre-/syncopal event during strenuous exercise and elevated cardiac biomarkers. Diverse initial symptoms prompted tailored investigations. Adequate training, medical assessments, and awareness of syncope triggers are essential for marathon participants. Caution and pacing strategies are crucial, especially among novices in competitive running. This information is pertinent given the growing popularity of marathon events and prompts a standardized diagnostic approach after these events.

12.
Neurocrit Care ; 19(3): 320-8, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23949477

RESUMEN

BACKGROUND: Brain oxygen (PbtO2) monitoring can help guide care of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) patients. The relationship between PbtO2-directed therapy and long-term outcome is unclear. We hypothesized that responsiveness to PbtO2-directed interventions is associated with outcome. METHODS: Seventy-six aSAH patients who underwent PbtO2 monitoring were included. Long-term outcome [Glasgow Outcome Score-Extended (GOS-E) and modified Rankin Scale (mRS)] was ascertained using the social security death database and structured telephone interviews. Univariate and multivariate regression were used to identify variables that correlated with outcome. RESULTS: Data from 64 patients were analyzed (12 were lost to follow-up). There were 530 episodes of compromised PbtO2 (<20 mmHg) during a total of 7,174 h of monitor time treated with 1,052 interventions. Forty-two patients (66 %) survived to discharge. Median follow-up was 8.5 months (range 0.1-87). At most recent follow-up 35 (55 %) patients were alive, and 28 (44 %) had a favorable outcome (mRS ≤3). In multivariate ordinal regression analysis, only age and response to PbtO2-directed intervention correlated significantly with outcome. Increased age was associated with worse outcome (coeff. 0.8, 95 % CI 0.3-1.3, p = 0.003), and response to PbtO2-directed intervention was associated with improved outcome (coeff. -2.12, 95 % CI -4.0 to -0.26, p = 0.03). Patients with favorable outcomes had a 70 % mean rate of response to PbtO2-directed interventions whereas patients with poor outcomes had a 45 % response rate (p = 0.005). CONCLUSIONS: Response to PbtO2-directed intervention is associated with improved long-term functional outcome in aSAH patients.


Asunto(s)
Encéfalo/metabolismo , Oxígeno/análisis , Hemorragia Subaracnoidea/metabolismo , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Encéfalo/cirugía , Femenino , Estudios de Seguimiento , Escala de Consecuencias de Glasgow , Humanos , Aneurisma Intracraneal/complicaciones , Aneurisma Intracraneal/terapia , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/métodos , Índice de Severidad de la Enfermedad , Hemorragia Subaracnoidea/etiología , Hemorragia Subaracnoidea/terapia , Factores de Tiempo
13.
Nanomaterials (Basel) ; 13(6)2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36986028

RESUMEN

Graphene is an excellent 2D material for vertical organic transistors electrodes due to its weak electrostatic screening and field-tunable work function, in addition to its high conductivity, flexibility and optical transparency. Nevertheless, the interaction between graphene and other carbon-based materials, including small organic molecules, can affect the graphene electrical properties and therefore, the device performances. This work investigates the effects of thermally evaporated C60 (n-type) and Pentacene (p-type) thin films on the in-plane charge transport properties of large area CVD graphene under vacuum. This study was performed on a population of 300 graphene field effect transistors. The output characteristic of the transistors revealed that a C60 thin film adsorbate increased the graphene hole density by (1.65 ± 0.36) × 1012 cm-2, whereas a Pentacene thin film increased the graphene electron density by (0.55 ± 0.54) × 1012 cm-2. Hence, C60 induced a graphene Fermi energy downshift of about 100 meV, while Pentacene induced a Fermi energy upshift of about 120 meV. In both cases, the increase in charge carriers was accompanied by a reduced charge mobility, which resulted in a larger graphene sheet resistance of about 3 kΩ at the Dirac point. Interestingly, the contact resistance, which varied in the range 200 Ω-1 kΩ, was not significantly affected by the deposition of the organic molecules.

14.
ACS Appl Nano Mater ; 6(11): 9444-9452, 2023 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-37325015

RESUMEN

Among the family of 2D materials, graphene is the ideal candidate as top or interlayer electrode for hybrid van der Waals heterostructures made of organic thin films and 2D materials due to its high conductivity and mobility and its inherent ability of forming neat interfaces without diffusing in the adjacent organic layer. Understanding the charge injection mechanism at graphene/organic semiconductor interfaces is therefore crucial to develop organic electronic devices. In particular, Gr/C60 interfaces are promising building blocks for future n-type vertical organic transistors exploiting graphene as tunneling base electrode in a two back-to-back Gr/C60 Schottky diode configuration. This work delves into the charge transport mechanism across Au/C60/Gr vertical heterostructures fabricated on Si/SiO2 using a combination of techniques commonly used in the semiconductor industry, where a resist-free CVD graphene layer functions as a top electrode. Temperature-dependent electrical measurements show that the transport mechanism is injection limited and occurs via Fowler-Nordheim tunneling at low temperature, while it is dominated by a nonideal thermionic emission at room and high temperatures, with energy barriers at room temperature of ca. 0.58 and 0.65 eV at the Gr/C60 and Au/C60 interfaces, respectively. Impedance spectroscopy confirms that the organic semiconductor is depleted, and the energy band diagram results in two electron blocking interfaces. The resulting rectifying nature of the Gr/C60 interface could be exploited in organic hot electron transistors and vertical organic permeable-base transistors.

15.
Nanoscale ; 15(20): 9203-9213, 2023 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-37157969

RESUMEN

We report a study on the relationship between the structure and electron transport properties of nanoscale graphene/pentacene interfaces. We fabricated graphene/pentacene interfaces from 10 to 30 nm thick needle-like pentacene nanostructures down to two-three layer (2L-3L) dendritic pentacene islands, and we measured their electron transport properties by conductive atomic force microscopy (C-AFM). The energy barrier at the interfaces, i.e., the energy position of the pentacene highest occupied molecular orbital (HOMO) with respect to the Fermi energy of graphene and the C-AFM metal tip was determined and discussed with an appropriate electron transport model (a double Schottky diode model and a Landauer-Buttiker model, respectively) taking into account the voltage-dependent charge doping of graphene. In both types of samples, the energy barrier at the graphene/pentacene interface is slightly larger than that at the pentacene/metal tip interface, resulting in 0.47-0.55 eV and 0.21-0.34 eV, respectively, for the 10-30 nm thick needle-like pentacene islands, and 0.92-1.44 eV and 0.67-1.05 eV, respectively, for the 2L-3L thick dendritic pentacene nanostructures. We attribute this difference to the molecular organization details of the pentacene/graphene heterostructures, with pentacene molecules lying flat on graphene in the needle-like pentacene nanostructures, while standing upright in the 2L-3L dendritic islands, as observed from Raman spectroscopy.

16.
ACS Nano ; 17(19): 18706-18715, 2023 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-37578964

RESUMEN

Bottom-up-synthesized graphene nanoribbons (GNRs) are an emerging class of designer quantum materials that possess superior properties, including atomically controlled uniformity and chemically tunable electronic properties. GNR-based devices are promising candidates for next-generation electronic, spintronic, and thermoelectric applications. However, due to their extremely small size, making electrical contact with GNRs remains a major challenge. Currently, the most commonly used methods are top metallic electrodes and bottom graphene electrodes, but for both, the contact resistance is expected to scale with overlap area. Here, we develop metallic edge contacts to contact nine-atom-wide armchair GNRs (9-AGNRs) after encapsulation in hexagonal boron-nitride (h-BN), resulting in ultrashort contact lengths. We find that charge transport in our devices occurs via two different mechanisms: at low temperatures (9 K), charges flow through single GNRs, resulting in quantum dot (QD) behavior with well-defined Coulomb diamonds (CDs), with addition energies in the range of 16 to 400 meV. For temperatures above 100 K, a combination of temperature-activated hopping and polaron-assisted tunneling takes over, with charges being able to flow through a network of 9-AGNRs across distances significantly exceeding the length of individual GNRs. At room temperature, our short-channel field-effect transistor devices exhibit on/off ratios as high as 3 × 105 with on-state current up to 50 nA at 0.2 V. Moreover, we find that the contact performance of our edge-contact devices is comparable to that of top/bottom contact geometries but with a significantly reduced footprint. Overall, our work demonstrates that 9-AGNRs can be contacted at their ends in ultra-short-channel FET devices while being encapsulated in h-BN.

17.
J Oral Maxillofac Surg ; 70(3): e185-9, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22374060

RESUMEN

PURPOSE: A novel endovascular therapy to treat a pseudoaneurysm as a complication of molar tooth extraction is described. PATIENTS AND METHODS: A 20-year-old man presented 2 weeks after third molar tooth extraction with an enlarging pulsatile jaw mass, identified as a facial artery pseudoaneurysm. Endovascular embolization with microcoils and a liquid embolic agent, Onyx, was performed. The use of Onyx in this manner is an off-label use. RESULTS: Immediately after treatment, the pulsatile mass resolved and remained obliterated at 2 months of follow-up. CONCLUSIONS: Onyx embolization of facial artery vascular lesions can be safely accomplished while avoiding microvascular complications and provides a satisfactory and durable result.


Asunto(s)
Aneurisma Falso/terapia , Enfermedades de las Arterias Carótidas/terapia , Dimetilsulfóxido/administración & dosificación , Embolización Terapéutica/métodos , Tercer Molar/cirugía , Polivinilos/administración & dosificación , Extracción Dental/efectos adversos , Aneurisma Falso/diagnóstico por imagen , Angiografía de Substracción Digital , Enfermedades de las Arterias Carótidas/diagnóstico por imagen , Cara/irrigación sanguínea , Cara/diagnóstico por imagen , Humanos , Masculino , Mandíbula , Complicaciones Posoperatorias , Resultado del Tratamiento , Ultrasonografía , Adulto Joven
19.
Neurocrit Care ; 17(1): 131-8, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21845489

RESUMEN

Observational clinical studies demonstrate that brain hypoxia is associated with poor outcome after severe traumatic brain injury (TBI). In this study, available medical literature was reviewed to examine whether brain tissue oxygen (PbtO2)-based therapy is associated with improved patient outcome after severe TBI. Clinical studies published between 1993 and 2010 that compared PbtO2-based therapy combined with intracranial and cerebral perfusion pressure (ICP/CPP)-based therapy to ICP/CPP-based therapy alone were identified from electronic databases, Index Medicus, bibliographies of pertinent articles, and expert consultation. For analysis, each selected paper had to have adequate data to determine odds ratios (ORs) and confidence intervals (CIs) of outcome described by the Glasgow outcome score (GOS). Seven studies that compared ICP/CPP and PbtO2- to ICP/CPP-based therapy were identified. There were no randomized studies and no comparison studies in children. Four studies, published in 2003, 2009, and 2010 that included 491 evaluable patients were used in the final analysis. Among patients who received PbtO2-based therapy, 121(38.8%) had unfavorable and 191 (61.2%) had a favorable outcome. Among the patients who received ICP/CPP-based therapy 104 (58.1%) had unfavorable and 75 (41.9%) had a favorable outcome. Overall PbtO2-based therapy was associated with favorable outcome (OR 2.1; 95% CI 1.4-3.1). Summary results suggest that combined ICP/CPP- and PbtO2-based therapy is associated with better outcome after severe TBI than ICP/CPP-based therapy alone. Cross-organizational practice variances cannot be controlled for in this type of review and so we cannot answer whether PbtO2-based therapy improves outcome. However, the potentially large incremental value of PbtO2-based therapy provides justification for a randomized clinical trial.


Asunto(s)
Lesiones Encefálicas/metabolismo , Lesiones Encefálicas/terapia , Encéfalo/metabolismo , Cuidados Críticos/métodos , Terapia por Inhalación de Oxígeno/métodos , Humanos , Presión Intracraneal/fisiología , Índices de Gravedad del Trauma , Resultado del Tratamiento
20.
ACS Appl Mater Interfaces ; 14(42): 48240-48249, 2022 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-36239396

RESUMEN

Hybrid van der Waals heterostructures based on 2D materials and/or organic thin films are being evaluated as potential functional devices for a variety of applications. In this context, the graphene/organic semiconductor (Gr/OSC) heterostructure could represent the core element to build future vertical organic transistors based on two back-to-back Gr/OSC diodes sharing a common graphene sheet, which functions as the base electrode. However, the assessment of the Gr/OSC potential still requires a deeper understanding of the charge carrier transport across the interface as well as the development of wafer-scale fabrication methods. This work investigates the charge injection and transport across Au/OSC/Gr vertical heterostructures, focusing on poly(3-hexylthiophen-2,5-diyl) as the OSC, where the PMMA-free graphene layer functions as the top electrode. The structures are fabricated using a combination of processes widely exploited in semiconductor manufacturing and therefore are suited for industrial upscaling. Temperature-dependent current-voltage measurements and impedance spectroscopy show that the charge transport across both device interfaces is injection-limited by thermionic emission at high bias, while it is space charge limited at low bias, and that the P3HT can be assumed fully depleted in the high bias regime. From the space charge limited model, the out-of-plane charge carrier mobility in P3HT is found to be equal to µ ≈ 2.8 × 10-4 cm2 V-1 s-1, similar to the in-plane mobility reported in previous works, while the charge carrier density is N0 ≈ 1.16 × 1015 cm-3, also in agreement with previously reported values. From the thermionic emission model, the energy barriers at the Gr/P3HT and Au/P3HT interfaces result in 0.30 eV and 0.25 eV, respectively. Based on the measured barriers heights, the energy band diagram of the vertical heterostructure is proposed under the hypothesis that P3HT is fully depleted.

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