A high-bandwidth voltage amplifier for driving piezoelectric actuators in high-speed atomic force microscopy.

High-speed atomic force microscopy (HS-AFM) is a technique capable of revealing the dynamics of biomolecules and living organisms at the nanoscale with a remarkable temporal resolution. The phase delay in the feedback loop dictates the achievable speed of HS-AFM instruments that rely on fast nanopositioners operated predominantly in conjunction with piezoelectric actuators (PEAs). The high capacitance and high operating voltage of PEAs make them difficult to drive.

Quality of MALDI-TOF mass spectra in routine diagnostics: results from an international external quality assessment including 36 laboratories from 12 countries using 47 challenging bacterial strains.

Objectives: Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is a widely used method for bacterial species identification. Incomplete databases and mass spectral quality (MSQ) still represent major challenges. Important proxies for MSQ are the number of detected marker masses, reproducibility, and measurement precision.

Fabrication of Optical Fibers with Multiple Coatings for Swelling-Based Chemical Sensing.

We discuss distributed chemical sensing based on the swelling of coatings of optical fibers. Volume changes in the coating induce strain in the fiber's glass core, provoking a local change in the refractive index which is detectable by distributed fiber optical sensing techniques. We describe methods to realize different coatings on a single fiber.

Pharmacokinetics of mometasone furoate delivered via two dry powder inhalers.

Background: QMF149 is an inhaled fixed-dose combination of indacaterol acetate and mometasone furoate (MF) delivered via Breezhaler®, under development for once-daily treatment of asthma. MF delivered via Twisthaler® is approved as Asmanex® Twisthaler® for the treatment of asthma. Bridging of MF delivered via Twisthaler® to MF delivered via Breezhaler® was undertaken as part of QMF149 development to enable dose comparisons between the devices.

Swelling-Based Distributed Chemical Sensing with Standard Acrylate Coated Optical Fibers.

Distributed chemical sensing is demonstrated using standard acrylate coated optical fibers. Swelling of the polymer coating induces strain in the fiber's silica core provoking a local refractive index change which is detectable all along an optical fiber by advanced distributed sensing techniques. Thermal effects can be discriminated from strain using uncoated fiber segments, leading to more accurate strain readings.

Liquid Flow Meter by Fiber-Optic Sensing of Heat Propagation.

Monitoring fluid flow rates is imperative for a variety of industries including biomedical engineering, chemical engineering, the food industry, and the oil and gas industries. We propose a flow meter that, unlike turbine or pressure-based sensors, is not flow intrusive, requires zero maintenance, has low risk of clogging, and is compatible with harsh conditions. Using optical fiber sensing, we monitor the temperature distribution along a fluid conduit.

High-Order Polynomial Fitting Assistance for Fast Double-Peak Finding in Brillouin-Distributed Sensing.

A high-order polynomial fitting method is proposed to accelerate the computation of double-Gaussian fitting in the retrieval of the Brillouin frequency shifts (BFS) in optical fibers showing two local Brillouin peaks. The method is experimentally validated in a distributed Brillouin sensor under different signal-to noise ratios and realistic spectral scenarios. Results verify that a sixth-order polynomial fitting can provide a reliable initial estimation of the dual local BFS values, which can be subsequently used as initial parameters of a nonlinear double-Gaussian fitting.

A randomized, double-blind study to compare the efficacy and safety of two doses of mometasone furoate delivered via Breezhaler® or Twisthaler® in patients with asthma.

Introduction: Mometasone furoate (MF) is the inhaled corticosteroid (ICS) component in the long-acting β-agonist (LABA)/ICS fixed-dose combination of indacaterol/MF, delivered via Breezhaler®, in development for asthma. MF at low (80 μg) and high (320 μg) doses delivered via Breezhaler® is expected to be comparable to MF at low (200 μg) and high (800 μg) doses respectively, delivered via Twisthaler®.

Methods: This was a randomized, double-blind, double-dummy, four-week, parallel-group study of 739 adolescents and adults with persistent asthma.

Mass Flow Monitoring by Distributed Fiber Optical Temperature Sensing.

We developed a novel method to monitor mass flow based on distributed fiber optical temperature sensing. Examination of the temporal and spatial temperature distribution along the entire length of a locally heated fluidic conduit reveals heat flow under forced convection. Our experimental results are in good agreement with two-dimensional finite element analysis that couples fluid dynamic and heat transfer equations.

Nanoscale imaging of charge carrier transport in water splitting photoanodes.

The performance of energy materials hinges on the presence of structural defects and heterogeneity over different length scales. Here we map the correlation between morphological and functional heterogeneity in bismuth vanadate, a promising metal oxide photoanode for photoelectrochemical water splitting, by photoconductive atomic force microscopy. We demonstrate that contrast in mapping electrical conductance depends on charge transport limitations, and on the contact at the sample/probe interface.

Electrostatically actuated encased cantilevers.

Encased cantilevers are novel force sensors that overcome major limitations of liquid scanning probe microscopy. By trapping air inside an encasement around the cantilever, they provide low damping and maintain high resonance frequencies for exquisitely low tip-sample interaction forces even when immersed in a viscous fluid. Quantitative measurements of stiffness, energy dissipation and tip-sample interactions using dynamic force sensors remain challenging due to spurious resonances of the system.

Cowpea ( L. Walp) hosts several widespread bradyrhizobial root nodule symbionts across contrasting agro-ecological production areas in Kenya.

Cowpea ( L. Walp.) is an important African food legume suitable for dry regions.

Evaluation of MALDI-TOF mass spectrometry for the competitiveness analysis of selected indigenous cowpea (Vigna unguiculata L. Walp.) Bradyrhizobium strains from Kenya.

Cowpea N fixation and yield can be enhanced by selecting competitive and efficient indigenous rhizobia. Strains from contrasting agro-ecologies of Kilifi and Mbeere (Kenya) were screened. Two pot experiments were established consisting of 13 Bradyrhizobium strains; experiment 1 (11 Mbeere + CBA + BK1 from Burkina Faso), experiment 2 (12 Kilifi + CBA).

Tracing of Two Strains in the Root and Rhizoplane of Maize, as Related to Their Plant Growth-Promoting Effect in Contrasting Soils.

TaqMan-based quantitative PCR (qPCR) assays were developed to study the persistence of two well-characterized strains of plant growth-promoting rhizobacteria (PGPR), Pf153 and sp. DSMZ 13134, in the root and rhizoplane of inoculated maize plants. This was performed in pot experiments with three contrasting field soils (Buus, Le Caron and DOK-M).

Two Major Clades of Bradyrhizobia Dominate Symbiotic Interactions with Pigeonpea in Fields of Côte d'Ivoire.

In smallholder farms of Côte d'Ivoire, particularly in the northeast of the country, (pigeonpea) has become an important crop because of its multiple beneficial facets. Pigeonpea seeds provide food to make ends meet, are sold on local markets, and aerial parts serve as forage for animals. Since it fixes atmospheric nitrogen in symbiosis with soil bacteria collectively known as rhizobia, also improves soil fertility and reduces fallow time.

Ribosomal protein biomarkers provide root nodule bacterial identification by MALDI-TOF MS.

Accurate identification of soil bacteria that form nitrogen-fixing associations with legume crops is challenging given the phylogenetic diversity of root nodule bacteria (RNB). The labor-intensive and time-consuming 16S ribosomal RNA (rRNA) sequencing and/or multilocus sequence analysis (MLSA) of conserved genes so far remain the favored molecular tools to characterize symbiotic bacteria. With the development of mass spectrometry (MS) as an alternative method to rapidly identify bacterial isolates, we recently showed that matrix-assisted laser desorption ionization (MALDI) time-of-flight (TOF) can accurately characterize RNB found inside plant nodules or grown in cultures.

Height drift correction in non-raster atomic force microscopy.

We propose a novel method to detect and correct drift in non-raster scanning probe microscopy. In conventional raster scanning drift is usually corrected by subtracting a fitted polynomial from each scan line, but sample tilt or large topographic features can result in severe artifacts. Our method uses self-intersecting scan paths to distinguish drift from topographic features.

Distribution and identification of culturable airborne microorganisms in a Swiss milk processing facility.

Airborne communities (mainly bacteria) were sampled and characterized (concentration levels and diversity) at 1 outdoor and 6 indoor sites within a Swiss dairy production facility. Air samples were collected on 2 sampling dates in different seasons, one in February and one in July 2012 using impaction bioaerosol samplers. After cultivation, isolates were identified by mass spectrometry (matrix-assisted laser desorption/ionization-time-of-flight) and molecular (sequencing of 16S rRNA and rpoB genes) methods.

Charge trapping states at the SiO2-oligothiophene monolayer interface in field effect transistors studied by Kelvin probe force microscopy.

Using Kelvin probe force microscopy (KPFM) we studied the local charge trapping states at the SiO2-oligothiophene interface in a field effect transistor (FET), where SiO2 is the gate dielectric. KPFM reveals surface potential inhomogeneities within the oligothiophene monolayer, which correlate with its structure. A large peak of trap states with energies in the oligothiophene's band gap due to hydroxyl groups is present at the oxide surface.

Improved accuracy and speed in scanning probe microscopy by image reconstruction from non-gridded position sensor data.

Scanning probe microscopy (SPM) has facilitated many scientific discoveries utilizing its strengths of spatial resolution, non-destructive characterization and realistic in situ environments. However, accurate spatial data are required for quantitative applications but this is challenging for SPM especially when imaging at higher frame rates. We present a new operation mode for scanning probe microscopy that uses advanced image processing techniques to render accurate images based on position sensor data.

Identification of cryptic Anopheles mosquito species by molecular protein profiling.

Vector control is the mainstay of malaria control programmes. Successful vector control profoundly relies on accurate information on the target mosquito populations in order to choose the most appropriate intervention for a given mosquito species and to monitor its impact. An impediment to identify mosquito species is the existence of morphologically identical sibling species that play different roles in the transmission of pathogens and parasites.

A rapid MALDI-TOF MS identification database at genospecies level for clinical and environmental Aeromonas strains.

The genus Aeromonas has undergone a number of taxonomic and nomenclature revisions over the past 20 years, and new (sub)species and biogroups are continuously described. Standard identification methods such as biochemical characterization have deficiencies and do not allow clarification of the taxonomic position. This report describes the development of a matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) identification database for a rapid identification of clinical and environmental Aeromonas isolates.

In situ identification of plant-invasive bacteria with MALDI-TOF mass spectrometry.

Rhizobia form a disparate collection of soil bacteria capable of reducing atmospheric nitrogen in symbiosis with legumes. The study of rhizobial populations in nature involves the collection of large numbers of nodules found on roots or stems of legumes, and the subsequent typing of nodule bacteria. To avoid the time-consuming steps of isolating and cultivating nodule bacteria prior to genotyping, a protocol of strain identification based on the comparison of MALDI-TOF MS spectra was established.

Identification of field-caught Culicoides biting midges using matrix-assisted laser desorption/ionization time of flight mass spectrometry.

Culicoides biting midges are of great importance as vectors of pathogens and elicitors of allergy. As an alternative for the identification of these tiny insects, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was evaluated. Protein mass fingerprints were determined for 4-5 field-caught reference (genetically confirmed) individuals of 12 Culicoides species from Switzerland, C.