Microfabricated palladium-based membranes for hydrogen separation

The goal of this project was to fabricate thin and defect-free Pd-based membranes. This is thought to be accomplished by using techniques of microfabrication technology [60-62]. In order to show their potential, the fabricated membranes are then used as hydrogen purifiers to get high quality hydrogen, and as membrane reactors for several dehydrogenation reactions

Wafer-scale fabrication of high-quality tunable gold nanogap arrays for surface-enhanced Raman scattering

We report a robust and high-yield fabrication method for wafer-scale patterning of high-quality arrays of dense gold nanogaps, combining displacement Talbot lithography based shrink-etching with dry etching, wet etching, and thin film deposition techniques. By using the self-sharpening of -oriented silicon crystal planes during the wet etching process, silicon structures with extremely smooth nanogaps are obtained. Subsequent conformal deposition of a silicon nitride layer and a gold layer results in dense arrays of narrow gold nanogaps. Using this method, we successfully fabricate high-quality Au nanogaps down to 10 nm over full wafer areas. Moreover, the gap spacing can be tuned by changing the thickness of deposited Au layers. Since the roughness of the template is minimized by the crystallographic etching of silicon, the roughness of the gold nanogaps depends almost exclusively on the roughness of the sputtered gold layers. Additionally, our fabricated Au nanogaps show a significant enhancement of surface-enhanced Raman scattering (SERS) signals of benzenethiol molecules chemisorbed on the structure surface, at an average enhancement factor up to 1.5 x 10(6)

Targeted next-generation sequencing on hirschsprung disease: A pilot study exploits DNA pooling

To adopt an efficient approach of identifying rare variants possibly related to Hirschsprung disease (HSCR), a pilot study was set up to evaluate the performance of a newly designed protocol for next generation targeted resquencing. In total, 20 Chinese HSCR patients and 20 Chinese sex-matched individuals with no HSCR were included, for which coding sequences (CDS) of 62 genes known to be in signaling pathways relevant to enteric nervous system development were selected for capture and sequencing. Blood DNAs from eight pools of five cases or controls were enriched by PCR-based RainDance technology (RDT) and then sequenced on a 454 FLX platform. As technical validation, five patients from case Pool-3 were also independently enriched by RDT, indexed with barcode and sequenced with sufficient coverage. Assessment for CDS single nucleotide variants showed DNA pooling performed well (specificity/sensitivity at 98.4%/83.7%) at the common variant level; but relatively worse (specificity/sensitivity at 65.5%/61.3%) at the rare variant level. Further Sanger sequencing only validated five out of 12 rare damaging variants likely involved in HSCR. Hence more improvement at variant detection and sequencing technology is needed to realize the potential of DNA pooling for large-scale resequencing projects. © 2014 John Wiley & Sons Ltd/University College London.postprin

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Shedding Light on Axial Stress Effect on Resonance Frequencies of Nanocantilevers

5 figuras, 7 páginasThe detection back-action phenomenon has received little attention in physical, chemical, and biological sensors based on nanomechanical systems. We show that this effect is very significant in ultrathin bimetallic cantilevers, in which the laser beam that probes the picometer scale vibration largely modifies the resonant frequencies of the system. The light back-action effect is nonlinear, and some resonant frequencies can even be reduced to a half with laser power intensities of 2 mW. We demonstrate that this effect arises from the stress and strain generated by the laser heating. The experiments are explained by two-dimensional nonlinear elasticity theory and supported by finite element simulations. The found phenomenology is intimately connected to the old unsolved problem about the effect of surface stress on the resonance frequency of singly clamped beams. The results indicate that to achieve the ultimate detection limits with nanomechanical resonators one must consider the uncertainty due to the detection back-action.The authors acknowledge financial support from the Spanish Science Ministry through Projects TEC2009-14517-C02, TRA2009-0117, and CSD2007-00010.Peer reviewe

Novel Top-Down Wafer-Scale Fabrication of Single Crystal Silicon Nanowires

A now low-cost, top-down nanowire fabrication technology Is presented not requiring nanolithography and suitable for any conventional microtechnology cleanroom facility. This novel wafer-scale process technology uses a combination of angled thin-film deposition and etching of a metal layer In a precisely defined cavity with a single micrometer-scale photolithography step. Electrically functional silicon and metallic nanowires with lengths up to several millimeters, lateral widths of similar to 100 nm, and thicknesses similar to 20 nm have been realized and tested. Device characterization Includes a general description of device operation, electrochemical biasing, and sensitivity for sensor applications followed by electrical measurements showing linear I-v characteristics with specific contact resistivity rho(c) similar to 4 x 10(-4) Omega cm(2) and electrochemical behavior of the oxidized silicon nanowires Is described with the site-binding mode

Arrays of dual nanomechanical resonators for selective biological detection

Arrays of small nanomechanical resonators with dual geometry have been fabricated for sensitive biological detection. The arrays consist of silicon nitride resonating 100 nm thick cantilevers with sensing gold areas alternately placed on the free and fixed cantilever ends. The Au areas act as sensing regions as can be functionalized by means of thiol chemistry. The nanomechanical arrays provide a double flavor of the adsorbed molecules: the added mass reported by the cantilevers with the Au area at the tip and the nanoscale elasticity reported by the cantilevers with the Au area at the clamp. The devices were applied for DNA detection based on Watson-Crick pairing rules. The proposed design for nanomechanical resonators provides higher specificity for DNA sensing in comparison with conventional single cantilevers. The nanoscale elasticity induced by the DNA hybridization arises from the intermolecular interactions between the adsorbates bound to the cantilever and the surface stress.D.R. acknowledges the fellowship funded by the Autonomous Community of Madrid (CAM). E.G.-S. acknowledges a fellowship funded by C.S.I.C. M.A.-H. acknowledges a contract funded by the Spanish Ministry of Science. J.T. and M.C. acknowledge financial support by the Spanish Ministry of Science under Grant Nos. TEC2006-10316 and CSD 2007-00010 and by the Autonomous Community of Madrid under contract S-0505/MAT-0283.Peer Reviewe

Preparation and gas sensing properties of nanocomposite polymers on micro-Interdigitated electrodes for detection of volatile organic compounds at room temperature

A room-temperature chemocapacitive gas sensor based on polymeric nanocomposites (NCs) consisting of amine-terminated silicon nanoparticles (Si NPs-NH2) and poly (4-vinylphenol) was fabricated on a micro-gap interdigitated electrode (M-IDE), and used for the detection of acetone. Several polymers were explored to capture acetone, of which poly (4-vinylphenol) showed best results. The response of the sensor was significantly improved by the addition of silicon nanoparticles to the polymer layer. The response characteristics of the NC film towards volatile organic compounds (VOCs) were determined and compared with the pristine polymeric layer in this study. It was shown that the polymeric NC layer can detect acetone at room temperature within one minute. The sensing response towards acetone at room temperature proved that the turn–on and −off exposure to this analyte was reversible with good reproducibility (5% decay) after multiple cycles of gas exposure. The proof-of-concept results are promising for the development of novel gas detectors that are applicable in many fields such as industrial and laboratorial security.</p

Preparation and gas sensing properties of nanocomposite polymers on micro-Interdigitated electrodes for detection of volatile organic compounds at room temperature

A room-temperature chemocapacitive gas sensor based on polymeric nanocomposites (NCs) consisting of amine-terminated silicon nanoparticles (Si NPs-NH2) and poly (4-vinylphenol) was fabricated on a micro-gap interdigitated electrode (M-IDE), and used for the detection of acetone. Several polymers were explored to capture acetone, of which poly (4-vinylphenol) showed best results. The response of the sensor was significantly improved by the addition of silicon nanoparticles to the polymer layer. The response characteristics of the NC film towards volatile organic compounds (VOCs) were determined and compared with the pristine polymeric layer in this study. It was shown that the polymeric NC layer can detect acetone at room temperature within one minute. The sensing response towards acetone at room temperature proved that the turn–on and −off exposure to this analyte was reversible with good reproducibility (5% decay) after multiple cycles of gas exposure. The proof-of-concept results are promising for the development of novel gas detectors that are applicable in many fields such as industrial and laboratorial security.</p