Publications by authors named "Thomas Stelzner"

Background: Up to 50% of chronic obstructive pulmonary disease (COPD) patients do not receive recommended care for COPD. To address this issue, we developed Proactive Integrated Care (Proactive iCare), a health care delivery model that couples integrated care with remote monitoring.

Methods: We conducted a prospective, quasi-randomized clinical trial in 511 patients with advanced COPD or a recent COPD exacerbation, to test whether Proactive iCare impacts patient-centered outcomes and health care utilization.

View Article and Find Full Text PDF

Aligned arrays of silicon nanowires (aa-Si NWs) allow the exploitation of Si NWs in a scalable way. Previous studies explored the influence of the Si NWs' number, doping density, and diameter on the related electrical performance. Nevertheless, the origin of the observed effects still not fully understood.

View Article and Find Full Text PDF

Technological implementation of nanowires (NWs) requires these components to be organized with controlled orientation and density on various substrates. Here, we report on a simple and efficient route for the deposition of highly ordered and highly aligned NW arrays on a wide range of receiver substrates, including silicon, glass, metals, and flexible plastics with controlled density. The deposition approach is based on spray-coating of a NW suspension under controlled conditions of the nozzle flow rate, droplet size of the sprayed NWs suspension, spray angle, and the temperature of the receiver substrate.

View Article and Find Full Text PDF

Silicon nanowire field-effect transistors (Si NW FETs) have been used as powerful sensors for chemical and biological species. The detection of polar species has been attributed to variations in the electric field at the conduction channel due to molecular gating with polar molecules. However, the detection of nonpolar analytes with Si NW FETs has not been well understood to date.

View Article and Find Full Text PDF

Silicon nanowire field effect transistors (Si NW FETs) are emerging as powerful sensors for direct detection of biological and chemical species. However, the low sensitivity of the Si NW FET sensors toward nonpolar volatile organic compounds (VOCs) is problematic for many applications. In this study, we show that modifying Si NW FETs with a silane monolayer having a low fraction of Si-O-Si bonds between the adjacent molecules greatly enhances the sensitivity toward nonpolar VOCs.

View Article and Find Full Text PDF

Here, we report on a simple, catalyst-free route for obtaining highly versatile subsequent functionalization on Si nanowires and Si(111) substrates. The versatility of this approach allows subsequent functionalization not only for organic species but also for inorganic (nanomaterial) species. The method has the advantage of controlling the density of reactive cross-linkers without affecting the stability of the Si samples and without having metallic (or catalyst) residues on the surface.

View Article and Find Full Text PDF

A new method to prepare plasmonically active noble metal nanostructures on large surface area silicon nanowires (SiNWs) mediated by atomic layer deposition (ALD) technology has successfully been demonstrated for applications of surface-enhanced Raman spectroscopy (SERS)-based sensing. As host material for the plasmonically active nanostructures we use dense single-crystalline SiNWs with diameters of less than 100 nm as obtained by a wet chemical etching method based on silver nitrate and hydrofluoric acid solutions. The SERS active metal nanoparticles/islands are made from silver (Ag) shells as deposited by autometallography on the core nanoislands made from platinum (Pt) that can easily be deposited by ALD in the form of nanoislands covering the SiNW surfaces in a controlled way.

View Article and Find Full Text PDF

Silicon nanowire arrays were patterned onto silicon chips by a combination of lithography and chemical vapor deposition using the vapor-liquid-solid growth method. Thus, highly reproducible sample deposition zones were obtained that were used for laser desorption ionization (LDI) mass spectrometric analysis of lipidic species with lithium salts as dopants. Using a conventional UV laser (337 nm), hydrocarbons and numerous lipids (triglycerides, diglycerides, wax esters) could be effectively lithiated yielding [M + Li](+) ions.

View Article and Find Full Text PDF

Silicon nanowires (Si NWs) terminated with methyl functionalities exhibit higher oxidation resistance under ambient conditions than equivalent 2D Si(100) and 2D Si(111) surfaces having similar or 10-20% higher initial coverage. The kinetics of methyl adsorption as well as complementary surface analysis by XPS and ToF SIMS attribute this difference to the formation of stronger Si-C bonds on Si NWs, as compared to 2D Si surfaces. This finding offers the possibility of functionalising Si NWs with minimum effect on the conductance of the near-gap channels leading towards more efficient Si NW electronic devices.

View Article and Find Full Text PDF

We report on Si NWs modified by covalent scaffolds, via SiC bonds, that give nearly full coverage of the Si atop sites and, at the same time, provide a route for subsequent functionalization. The obtained CH(3)CHCHSi NWs exhibit superior oxidation resistance over Si NWs that are modified with CH(3) or CH(3)CC functionalities, which give nearly full coverage of the Si atop site too.

View Article and Find Full Text PDF

Silicon nanowires grown by the vapor-liquid-solid (VLS) mechanism catalyzed by gold show gold caps (droplets) approximately 20-500 nm in diameter with a half spherical towards almost spherical shape. These gold droplets are well suited to exploit the surface-enhanced Raman scattering (SERS) effect and could be used for tip-enhanced Raman spectroscopy (TERS). The gold droplet of a nanowire attached to an atomic force microscopy (AFM) tip could locally enhance the Raman signal and increase the spatial resolution.

View Article and Find Full Text PDF