@article{li_zhang_yu_dai_wei_2019, title={Aptamer-Based Fluorescent Sensor Array for Multiplexed Detection of Cyanotoxins on a Smartphone}, volume={91}, ISSN={["1520-6882"]}, url={https://doi.org/10.1021/acs.analchem.9b00750}, DOI={10.1021/acs.analchem.9b00750}, abstractNote={Developing easy-to-use and miniaturized detectors is essential for in-field monitoring of environmentally hazardous substances, such as the cyanotoxins. We demonstrated a differential fluorescent sensor array made of aptamers and single-stranded DNA (ssDNA) dyes for multiplexed detection and discrimination of four common cyanotoxins with an ordinary smartphone within 5 minutes of reaction. The assay reagents were preloaded and dried in a microfluidic chip with a long shelf-life over 60 days. Upon the addition of analyte solutions, competitive binding of cyanotoxin to the specific aptamer-dye conjugate occurred. A zone-specific and concentration-dependent reduction in the green fluorescence was observed as a result of the aptamer conformation change. The aptasensors are fully optimized by quantification of their dissociation constants, tuning the stoichiometric ratios of reaction mixtures, and implementation of an internal intensity correction step. The fluorescent sensor array allowed for accurate identification and measurement of four important cyanotoxins, including anatoxin-a (ATX), cylindrospermopsin (CYN), nodularin (NOD), and microcystin-LR (MC-LR), in parallel, with the limit of detection (LOD) down to a few nanomolar (< 3 nM), which is close to the World Health Organization's guideline for the maximum concentration allowed in drinking water. The smartphone-based sensor platform also showed remarkable chemical specificity against potential interfering agents in water. The performance of the system was tested and validated with real lake water samples which were contaminated with trace levels of individual cyano-toxins as well as binary, ternary, and quaternary mixtures. Finally, a smartphone app interface has been developed for rapid on-site data processing and result display.}, number={16}, journal={ANALYTICAL CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Li, Zheng and Zhang, Shengwei and Yu, Tao and Dai, Zhiming and Wei, Qingshan}, year={2019}, month={Aug}, pages={10448–10457} }
 @misc{kleinstreuer_zhang_li_2008, title={Modeling airflow and particle transport/deposition in pulmonary airways}, volume={163}, ISSN={["1878-1519"]}, DOI={10.1016/j.resp.2008.07.002}, abstractNote={A review of research papers is presented, pertinent to computer modeling of airflow as well as nano- and micron-size particle deposition in pulmonary airway replicas. The key modeling steps are outlined, including construction of suitable airway geometries, mathematical description of the air-particle transport phenomena and computer simulation of micron and nanoparticle depositions. Specifically, diffusion-dominated nanomaterial deposits on airway surfaces much more uniformly than micron particles of the same material. This may imply different toxicity effects. Due to impaction and secondary flows, micron particles tend to accumulate around the carinal ridges and to form "hot spots", i.e., locally high concentrations which may lead to tumor developments. Inhaled particles in the size range of 20nm< or =dp< or =3microm may readily reach the deeper lung region. Concerning inhaled therapeutic particles, optimal parameters for mechanical drug-aerosol targeting of predetermined lung areas can be computed, given representative pulmonary airways.}, number={1-3}, journal={RESPIRATORY PHYSIOLOGY & NEUROBIOLOGY}, author={Kleinstreuer, Clement and Zhang, Zhe and Li, Zheng}, year={2008}, month={Nov}, pages={128–138} }
 @article{li_kleinstreuer_zhang_2007, title={Particle deposition in the human tracheobronchial airways due to transient inspiratory flow patterns}, volume={38}, ISSN={["1879-1964"]}, DOI={10.1016/j.jaerosci.2007.03.010}, abstractNote={Considering realistic tracheobronchial airways, transient airflow structures and micro-particle deposition patterns were simulated with an in-house finite-volume code for typical inhalation waveforms and Stokes numbers, i.e., the average flow rates at the trachea inlet, Qin,av, are 15 and 60L/min and the mean Stokes number at the trachea inlet, Stmean,trachea, is in the range of 0.0229⩽Stmean,trachea⩽0.0915, respectively. While the overall airflow fields exhibit similar characteristics, the local flow patterns which influence particle deposition are largely affected by secondary flows (for both Qin,av=15 and 60L/min) as well as airflow turbulence (when Qin,av=60L/min). The particle deposition fraction is a strongly transient function according to a given inhalation waveform. In light of the importance of targeted drug-aerosol delivery, it is shown that the relation between particle-release positions at the trachea inlet and particle depositions at specific lung sites are greatly influenced by the complex airway geometry and the flow-rate magnitude. For laminar flow, the particle-release points are deterministic and unique, as required for optimal drug-aerosol targeting.}, number={6}, journal={JOURNAL OF AEROSOL SCIENCE}, author={Li, Zheng and Kleinstreuer, Clement and Zhang, Zhe}, year={2007}, month={Jun}, pages={625–644} }
 @article{li_kleinstreuer_zhang_2007, title={Simulation of airflow fields and microparticle deposition in realistic human lung airway models. Part I: Airflow patterns}, volume={26}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2007.02.003}, abstractNote={In Part I, transient and steady laminar airflow fields were simulated with an in-house finite volume code for realistic upper airway models subject to different inlet conditions and geometric features. Axial velocities and secondary flows were compared at key time levels during the acceleration/deceleration phase of inhaled air and for steady-state inhalation. The main results can be summarized as follows. Considering two acceleration and deceleration time levels during transient inhalation as well as steady-state inhalation generating the same inlet Reynolds number, Rein-mean=1201, the airflow patterns are quite similar. However, stronger axial and secondary velocities occur at all upper branch locations during flow deceleration because of the dynamic lingering effect. In general, the axial velocity profiles at steady state are very close to those at the point of deceleration. Variations in upper airway geometry, e.g., in-plane vs. out-of-plane configurations, have a significant effect on the airflow fields, although the primary airflow structures are similar in both idealized and more realistic airway configurations. The type of velocity inlet condition and existence of cartilaginous rings also influence the flow field; however, their impact is less important than changes in spatial angles.}, number={5}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Li, Zheng and Kleinstreuer, Clement and Zhang, Zhe}, year={2007}, pages={632–649} }
 @article{li_kleinstreuer_zhang_2007, title={Simulation of airflow fields and microparticle deposition in realistic human lung airway models. Part II: Particle transport and deposition}, volume={26}, ISSN={["1873-7390"]}, DOI={10.1016/j.euromechflu.2007.02.004}, abstractNote={In Part II, given the airflow fields discussed in Part I, microparticle deposition for a practical range of Stokes numbers, 0.025⩽St⩽0.102, has been simulated and analyzed, comparing different temporal assumptions, inlet conditions and geometric configurations. The matching steady-state assumption with equivalent Reynolds and Stokes numbers achieves basically the same deposition fraction (DF) values as under transient inhalation conditions. When comparing parabolic vs. realistic inlet velocity profiles, total DF-values are higher for the parabolic inlet flow for all Stokes numbers. Geometric features, such as out-of-plane configurations and cartilaginous rings in the trachea, further change local deposited microparticle concentrations when compared with simple airway models. Furthermore, significant differences were recorded when comparing DFs in some branches of the present realistic model and the Weibel Type A model. For practical purposes, algebraic microparticle-deposition correlations, DF=DF(Re,St), have been obtained for both the left and right upper lung airways. Based on current research results, the out-of-plane model with tracheal rings and realistic inlet condition is recommended for future work.}, number={5}, journal={EUROPEAN JOURNAL OF MECHANICS B-FLUIDS}, author={Li, Zheng and Kleinstreuer, Clement and Zhang, Zhe}, year={2007}, pages={650–668} }