RESUMO
Optical antenna structures have revolutionized the field of nano-optics by confining light to deep subwavelength dimensions for spectroscopy and sensing. In this work, we fabricated coaxial optical antennae with sub-10-nanometer critical dimensions using helium ion lithography (HIL). Wavelength dependent transmission measurements were used to determine the wavelength-dependent optical response. The quality factor of 11 achieved with our HIL fabricated structures matched the theoretically predicted quality factor for the idealized flawless gold resonators calculated by finite-difference time-domain (FDTD). For comparison, coaxial antennae with 30 nm critical dimensions were fabricated using both HIL and the more common Ga focus ion beam lithography (Ga-FIB). The quality factor of the Ga-FIB resonators was 60% of the ideal HIL results for the same design geometry due to limitations in the Ga-FIB fabrication process.
RESUMO
The articular cartilage collagen network is an important research focus because network disruption results in cartilage degeneration and patient disability. The recently introduced helium ion microscope (HIM), with its smaller probe size, longer depth of field and charge neutralization, has the potential to overcome the inherent limitations of electron microscopy for visualization of collagen network features, particularly at the nanoscale. In this study, we evaluated the capabilities of the helium ion microscope for high-resolution visualization of the articular cartilage collagen network. Images of rabbit knee cartilage were acquired with a helium ion microscope; comparison images were acquired with a field emission scanning electron microscope (FE-SEM) and a transmission electron microscope (TEM). Sharpness of example high-resolution helium ion microscope and field emission scanning electron microscope images was quantified using the 25-75% rise distance metric. The helium ion microscope was able to acquire high-resolution images with unprecedented clarity, with greater sharpness and three-dimensional-like detail of nanoscale fibril morphologies and fibril connections, in samples without conductive coatings. These nanoscale features could not be resolved by field emission scanning electron microscopy, and three-dimensional network structure could not be visualized with transmission electron microscopy. The nanoscale three-dimensional-like visualization capabilities of the helium ion microscope will enable new avenues of investigation in cartilage collagen network research.
Assuntos
Cartilagem Articular/ultraestrutura , Colágeno/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Animais , Hélio , Microscopia Eletrônica , Microscopia Eletrônica de Varredura/instrumentação , Patela , CoelhosRESUMO
The availability of the Airyscan detector in the Zeiss LSM 880 has made possible the development of a new concept in fluctuation correlation spectroscopy using super-resolution. The Airyscan unit acquires data simultaneously on 32 detectors arranged in a hexagonal array. This detector opens up the possibility to use fluctuation methods based on time correlation at single points or at a number of points simultaneously, as well as methods based on spatial correlation in the area covered by the detector. Given the frame rate of this detector, millions of frames can be acquired in seconds, providing a robust statistical basis for fluctuation data. We apply the comprehensive analysis to the molecular fluctuations of free GFP diffusing in live cells at different subcellular compartments to show that at the nanoscale different cell environments can be distinguished by the comprehensive fluctuation analysis.
Assuntos
Espectrometria de Fluorescência/métodos , Correlação de Dados , Análise EspectralRESUMO
BACKGROUND: An increasing number of surgeons with different levels of experience with laparoscopic surgery and open obesity surgery have started to perform laparoscopic implantation of the Lap-Band. METHODS: An electronic patient data sheet was created and was mailed and e-mailed to all surgeons performing laparoscopic adjustable silicone gastric banding (LASGB) in Italy. Patients were recruited since January 1996. Data on 1,265 Lap-Band System operated patients (258 M/1,007 F; mean BMI 44.1, range 27.0-78.1; mean age 38, range 17-74 years) were collected from 23 surgeons performing this operation. RESULTS: Intra-operative mortality was absent. Post-operative mortality was 0.55% (7 patients) for causes not specifically related to LASGB implantation. The laparotomic conversion rate was 1.7% (22 patients). LASGB related complications occurred in 143 patients (11.3%). Pouch dilatation was diagnosed in 65 (5.2%), and 28 (2.2%) of these underwent re-operation. Band erosion was observed in 24 patients (1.9%). Port or connecting tube-port complications occurred in 54 patients (4.2%), 12 of whom required revision under general anesthesia. Follow-up was obtained at 6, 12, 18, 24, 36 and 48 months, and mean BMI was respectively 38.4, 35.1, 33.1, 30.2, 32.1 and 31.5. The percentage of patients observed at each follow-up was > 60%. There was no intra-operative mortality and no complication-related mortality, with acceptable weight loss. CONCLUSION: The LASGB operation is safe and effective, and deserves wider use for treatment of morbid obesity.
Assuntos
Gastroplastia/instrumentação , Laparoscopia , Próteses e Implantes , Adolescente , Adulto , Idoso , Gastroplastia/métodos , Humanos , Itália , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) is the most common bariatric operation. This study is a retrospective analysis of the multicenter Italian experience in patients with BMI > 50 over the last 4 years. METHODS: An electronic data sheet made for LAGB-operated patients since January 1996, was mailed and e-mailed to all surgeons involved in this kind of procedure in Italy. Items regarding patients with BMI > 50 were selected. Analysis used Fisher's exact test and logarithmic regression analysis (P < 0.05 significant). Data were expressed as mean +/- SD. RESULTS: 239 patients (13.3%), out of 1,797 Lap-Band operated patients entered the study (179F / 60M), with mean age 37.6 +/- 11.3 years (19-69) and mean BMI 54.6 +/- 4.8 (50.1-83.6). Laparotomic conversion rate was 5.4% (44/239). Postoperative complications occurred in 24 / 239 patients (9.0%). Follow-up was obtained in 218 / 218, 198 / 198, 121 /147, 75 / 93, 30 / 38 LAGB patients at 6,12, 24, 36, and 48 months respectively. At these time periods, mean BMI was 46.7, 43.9, 42.2, 41.9, and 39.3 kg/m2. At the same intervals, mean %EWL was 24.1, 34.1, 38.8, 38.9, and 52.9%. The number of patients with < 25% EWL at 12, 24, 36, and 48 months follow-up were 34, 10, 4, and 0. Serious co-morbidities (189 in 124 of 239, 57%) had completely resolved 1 year postoperatively in 74 / 124 of the patients (59.6%). CONCLUSION: Although super-obese patients following the LAGB remain obese with BMI > 35, in the short-term most lose their co-morbidities, with a very low morbidity and mortality rate.
Assuntos
Gastroplastia , Adulto , Idoso , Comorbidade , Feminino , Humanos , Itália , Laparoscopia , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/epidemiologia , Obesidade Mórbida/cirurgia , Análise de Regressão , Estudos RetrospectivosRESUMO
The authors report a case of severe revascularization syndrome which occurred following traumatic vascular lesion to a lower limb. They focus attention on the mechanisms which make this syndrome more frequent and more severe in traumatic lesions as opposed to that observed following acute arterial obstruction secondary to embolism or thrombosis.