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Darwiche K.,University of Duisburg - Essen | Baumbach J.I.,KIST Europe | Sommerwerck U.,University of Duisburg - Essen | Teschler H.,University of Duisburg - Essen | Freitag L.,University of Duisburg - Essen

Background: The exhaled breath of lung cancer patients contains volatile organic compounds (VOCs) that differ from those in healthy individuals. These VOCs can be detected with methods such as ion mobility spectrometry (IMS); their origin remains unknown. Methods: In 19 patients with lung cancer, exhaled breath was aspirated via the working channel of a flexible bronchoscope from both the tumor-bearing and the opposite lung and analyzed with IMS. Results: IMS measurement through the working channel of a bronchoscope was feasible and safe. In comparison to the opposite lung, we found two peaks that were significantly higher and three peaks that were significantly lower on the IMS of the tumor-bearing site. VOCs differ in concentration depending on the histologic subtype. Conclusion: Our results indicate that VOCs in lung cancer patients are produced locally in or around the tumor, and it is most likely that these VOCs represent underlying metabolic processes of the tumor. © 2011 Springer Science+Business Media, LLC. Source

Neuzil P.,Brno University of Technology | Neuzil P.,Institute Of Bioengineering And Nanotechnology, Singapore | Sun W.,Institute Of Bioengineering And Nanotechnology, Singapore | Sun W.,Bruker | And 2 more authors.
Applied Physics Letters

We report on a microfluidic system formed by 200 nl water droplets, encapsulated by a 600 nl mineral oil placed on a hydrophobically coated glass microscope cover slip. The micromachined heater underneath the glass was able to heat up the sample at a heating rate of 650°C/s, heating the water sample up to 200°C in less than 2s. The sample/glass and the sample/oil interface did not have nucleation centers, showing that the sample reached a superheated stage without the necessity of being pressurized to suppress boiling. This method can be utilized for various applications currently being conducted in autoclaves. © 2015 Author(s). Source

Ahmed D.,Pennsylvania State University | Muddana H.S.,Pennsylvania State University | Lu M.,Pennsylvania State University | French J.B.,Pennsylvania State University | And 6 more authors.
Analytical Chemistry

Eliciting a cellular response to a changing chemical microenvironment is central to many biological processes including gene expression, cell migration, differentiation, apoptosis, and intercellular signaling. The nature and scope of the response is highly dependent upon the spatiotemporal characteristics of the stimulus. To date, studies that investigate this phenomenon have been limited to digital (or step) chemical stimulation with little control over the temporal counterparts. Here, we demonstrate an acoustofluidic (i.e., fusion of acoustics and microfluidics) approach for generating programmable chemical waveforms that permits continuous modulation of the signal characteristics including the amplitude (i.e., sample concentration), shape, frequency, and duty cycle, with frequencies reaching up to 30 Hz. Furthermore, we show fast switching between multiple distinct stimuli, wherein the waveform of each stimulus is independently controlled. Using our device, we characterized the frequency-dependent activation and internalization of the β2-adrenergic receptor (β2-AR), a prototypic G-protein coupled receptor (GPCR), using epinephrine. The acoustofluidic-based programmable chemical waveform generation and switching method presented herein is expected to be a powerful tool for the investigation and characterization of the kinetics and other dynamic properties of many biological and biochemical processes. © 2014 American Chemical Society. Source

Bessa V.,University of Duisburg - Essen | Darwiche K.,University of Duisburg - Essen | Teschler H.,University of Duisburg - Essen | Sommerwerck U.,University of Duisburg - Essen | And 3 more authors.
International Journal for Ion Mobility Spectrometry

COPD is a disease characterised by a chronic inflammation of the airways and a not fully reversible airway obstruction. The spirometry is considered as gold-standard to diagnose the disease and to grade its severity. In this study we used the methodology of Ion Mobility Spectometry in order to detect Volatile Organic Compounds (VOCs) in exhaled breath of patients with COPD. The purpose of this study was to investigate if the VOCs detected in patients with COPD were different from the VOCs detected in exhaled breath of healthy controls. 13 COPD patients and 33 healthy controls were included in the study. Breath samples were collected via a side-steam Teflon tube and directly measured by an ion mobility spectrometer coupled to a multi capillary column (MCC/IMS). One peak was identified only in the patients group compared to the healthy control group. Consequently, the analysis of exhaled breath could be a useful tool to diagnose COPD. © 2011 Springer-Verlag. Source

Ahrberg C.D.,KIST Europe | Ahrberg C.D.,Sogang University | Manz A.,KIST Europe | Neuzil P.,Northwestern Polytechnical University | Neuzil P.,Brno University of Technology
Analytical Chemistry

We show the utilization of a recently developed cellphone-sized real-time polymerase chain reaction (PCR) device to detect Ebola virus RNA using single-step reverse transcription PCR (RT-PCR). The device was shown to concurrently perform four PCRs, each with a sample volume of 100 nL: one positive control with both Ebola and GAPDH RNA and one negative control. The last two positions were used to measure the GAPDH and the Ebola content of a sample. A comparison of threshold cycles (CT) from the two samples provided relative quantification. The entire process, which consisted of reverse transcription, PCR amplification, and melting curve analysis (MCA), was conducted in less than 37 min. The next step will be integration with a sample preparation unit to form an integrated sample-to-answer system for point-of-care infectious disease diagnostics. © 2016 American Chemical Society. Source

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