Bubble Printing of Layered Silicates: Surface Chemistry Effects and Picomolar Förster Resonance Energy Transfer Sensing.

The assembly of nanoparticles on surfaces in defined patterns has long been achieved via template-assisted methods that involve long deposition and drying steps and the need for molds or masks to obtain the desired patterns. Control over deposition of materials on surfaces via laser-directed microbubbles is a nascent technique that holds promise for rapid fabrication of devices down to the micrometer scale. However, the influence of surface chemistry on the resulting assembly using such approaches has so far not been studied. Herein, the printing of layered silicate nanoclays using a laser-directed microbubble was established. Significant differences in the macroscale structure of the printed patterns were observed for hydrophilic, pristine layered silicates compared to hydrophobic, modified layered silicates, which provided the first example of how the surface chemistry of such nanoscale objects results in changes in assembly with this approach. Furthermore, the ability of layered silicates to adsorb molecules at the interface was retained, which allowed the fabrication of proof-of-concept sensors based on Förster resonance energy transfer (FRET) from quantum dots embedded in the assemblies to bound dye molecules. The detection limit for Rhodamine 800 sensing via FRET was found to be on the order of 10-12 M, suggesting signal enhancement due to favorable interactions between the dye and nanoclay. This work sets the stage for future advances in the control of hierarchical assembly of nanoparticles by modification of surface chemistry while also demonstrating a quick and versatile approach to achieve ultrasensitive molecular sensors.

Automatic local resolution-based sharpening of cryo-EM maps.

MOTIVATION: Recent technological advances and computational developments have allowed the reconstruction of Cryo-Electron Microscopy (cryo-EM) maps at near-atomic resolution. On a typical workflow and once the cryo-EM map has been calculated, a sharpening process is usually performed to enhance map visualization, a step that has proven very important in the key task of structural modeling. However, sharpening approaches, in general, neglects the local quality of the map, which is clearly suboptimal. RESULTS: Here, a new method for local sharpening of cryo-EM density maps is proposed. The algorithm, named LocalDeblur, is based on a local resolution-guided Wiener restoration approach of the original map. The method is fully automatic and, from the user point of view, virtually parameter-free, without requiring either a starting model or introducing any additional structure factor correction or boosting. Results clearly show a significant impact on map interpretability, greatly helping modeling. In particular, this local sharpening approach is especially suitable for maps that present a broad resolution range, as is often the case for membrane proteins or macromolecules with high flexibility, all of them otherwise very suitable and interesting specimens for cryo-EM. To our knowledge, and leaving out the use of local filters, it represents the first application of local resolution in cryo-EM sharpening. AVAILABILITY AND IMPLEMENTATION: The source code (LocalDeblur) can be found at https://github.com/I2PC/xmipp and can be run using Scipion (http://scipion.cnb.csic.es) (release numbers greater than or equal 1.2.1). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Validation of electron microscopy initial models via small angle X-ray scattering curves.

MOTIVATION: Cryo electron microscopy (EM) is currently one of the main tools to reveal the structural information of biological macromolecules. The re-construction of three-dimensional (3D) maps is typically carried out following an iterative process that requires an initial estimation of the 3D map to be refined in subsequent steps. Therefore, its determination is key in the quality of the final results, and there are cases in which it is still an open issue in single particle analysis (SPA). Small angle X-ray scattering (SAXS) is a well-known technique applied to structural biology. It is useful from small nanostructures up to macromolecular ensembles for its ability to obtain low resolution information of the biological sample measuring its X-ray scattering curve. These curves, together with further analysis, are able to yield information on the sizes, shapes and structures of the analyzed particles. RESULTS: In this paper, we show how the low resolution structural information revealed by SAXS is very useful for the validation of EM initial 3D models in SPA, helping the following refinement process to obtain more accurate 3D structures. For this purpose, we approximate the initial map by pseudo-atoms and predict the SAXS curve expected for this pseudo-atomic structure. The match between the predicted and experimental SAXS curves is considered as a good sign of the correctness of the EM initial map. AVAILABILITY AND IMPLEMENTATION: The algorithm is freely available as part of the Scipion 1.2 software at http://scipion.i2pc.es/.

The Primary Obesity Surgery Endolumenal (POSE) procedure: one-year patient weight loss and safety outcomes.

BACKGROUND: Obesity is at epidemic proportions and increasing. Bariatric surgical procedures have demonstrated better durable weight loss than diet and exercise; however, risk may limit adoption of these procedures. Endoscopic procedures may offer less risk, lower cost, and satisfactory results, but limited safety and outcome data is available. The present report describes the Primary Obesity Surgery Endolumenal (POSE(™)) procedure, perioperative care, and 1-year safety and weight loss outcomes for a single center. METHODS: One hundred forty-seven patients undergoing the POSE procedure between July 2011 and January 2013 were followed for 1 year. Overall patient status and weight data were collected at baseline and at 3, 6, and 12 months. Outcomes included change in total weight loss (TWL), percentage of TWL (%TWL), percentage of excess weight loss (%EWL), and adverse events. RESULTS: Patients tolerated the procedure well with no serious short-term or long-term adverse events. All but 1 patient were discharged within 24 hours of the procedure. Baseline body mass index (BMI) was 38.0 ± 4.8 kg/m(2). Initial weight (106.8 ± 18.2 kg) was significantly reduced at 3, 6, and 12 months. At 1 year, 116 patients (79% of total) who were available for follow-up had a mean TWL of 16.6 ± 9.7 kg, %TWL of 15.1 ± 7.8, and %EWL of 44.9 ± 24.4. CONCLUSION: After 1-year follow-up, POSE was considered an effective, safe and well tolerated procedure for the treatment of patients with obesity.

Endoscopic sleeve gastroplasty for the treatment of obesity.

BACKGROUND AND STUDY AIMS: Emerging endoscopic techniques are minimally invasive and can mimic the anatomic alterations achieved by surgical sleeve gastrectomy. The objective of this study was to evaluate endoscopic sleeve gastroplasty. PATIENTS AND METHODS: This was a prospective, single-center study of 20 patients who underwent flexible endoscopic suturing for endoluminal gastric volume reduction. A multidisciplinary team provided postprocedure care. Patient status and weight were recorded at baseline, and at 1, 3, and 6 months after the procedure. RESULTS: There were no adverse events and all patients were discharged in less than 24 hours. Baseline mean body mass index was 38.5 kg/m(2), and mean age was 45.8 years. Initial body weight (108.5 ±â€Š14.9 kg) was significantly reduced. Following the procedure, the mean body weight reduction was 8.2 ±â€Š2.5 kg at 1 month (% of initial weight loss 7.6 %; P < 0.05), 13.6 ±â€Š4.8 kg at 3 months (12.4 % weight loss; P < 0.05), and 19.3 ±â€Š8.9 kg at 6 months (17.8 % weight loss; P < 0.05). CONCLUSION: Endoscopic sleeve gastroplasty can be effective for the treatment of patients with obesity.