Fabrication and characterization of a miniaturized planar voltammetric sensor array for use in an electronic tongue

A planar voltammetric sensor array for use in an electronic tongue was fabricated using a combination of microfabrication techniques. The techniques of e-beam evaporation and pulsed laser deposition were applied to prepare a device that contained all of the electrodes integrated on a silicon die (6 mm × 6 mm). The working electrodes were metals gold, platinum, iridium and rhodium. They were characterized by SEM and EDX, and by electrochemical investigation of the packaged dies with cyclic voltammetry in solutions of sulfuric acid and of ferrocene carboxylic acid in aqueous buffer solution. The robustness and reproducibility of the devices were assessed by potential cycling in acid solution.     

Stability of Local On‐Ramp Metering Control Laws

A framework for stability analysis of local on‐ramp metering control strategies based on the cell transmission model is presented. Within this framework, it is possible to formulate Lyapunov and input‐state stability results for on‐ramp metering control strategies in an open section of highway with on‐ramps. Using this analysis, recommendations for the design of on‐ramp metering control laws set points are derived. Two examples on the use of such analysis are presented. One deals with the stability analysis of a local on‐ramp metering control law and the other with the design of a disturbance observer that, used in combination with the local on‐ramp metering control law, provides a more robust response to traffic regulation. Simulation results are included that confirm the possibility of using this framework to test the impact of local on‐ramp metering control strategies.     

Spiral-shaped inertial stem cell device for high-throughput enrichment of iPSC-derived neural stem cells

Stem cell enrichment plays a critical role in both research and clinical applications. The typical method for stem cell enrichment may use invasive processes and takes a long period of time. Spiral-shaped microfluidic devices, which combine lift and Dean drag forces to direct cells of different sizes into separate trajectories, can be used to noninvasively process samples at a rate of milliliters per minute. This paper presents a simple 2-loop spiral-shaped inertial microfluidic devices with the aid of sheath flow to enrich neural stem cells (NSCs), derived from induced pluripotent stem cells. NSCs and spontaneously differentiated non-neural cells were mixed and flowed through the spiral-shaped devices. Samples collected at the outlets were analyzed for purity and recovery. It was found that the device focused the NSCs into a narrow trajectory, which could then be collected in two out of the eight outlets. The device was tested at different flow rates and found that the most highly enriched fractions (2.1×) with NSCs recovery 93% were achieved at the flow rate (3 ml/min). Next, we extended our investigation from 2-loop design to 10-loop design to eliminate the use of sheath flow. NSCs were enriched to 2.5×, but only 38% of the NSCs were recovered from the most enriched fractions. Spiral-shaped microfluidic devices are capable of rapid, label-free enrichment of target stem cells, and have great potential in point-of-care tissue preparation.     

Analysis of the HLA class I associated peptide repertoire in a hepatocellular carcinoma cell line reveals tumor-specific peptides as putative targets for immunotherapy

HLA class I molecules present peptides on the cell surface to CD8(+) T cells. The repertoire of peptides that associate to class I molecules represents the cellular proteome. Therefore, cells expressing different proteomes could generate different class I-associated peptide repertoires. A large number of peptides have been sequenced from HLA class I alleles, mostly from lymphoid cells. On the other hand, T cell immunotherapy is a goal in the fight against cancer, but the identification of T cell epitopes is a laborious task. Proteomic techniques allow the definition of putative T cell epitopes by the identification of HLA natural ligands in tumor cells. In this study, we have compared the HLA class I-associated peptide repertoire from the hepatocellular carcinoma (HCC) cell line SK-Hep-1 with that previously described from lymphoid cells. The analysis of the peptide pool confirmed that, as expected, the peptides from SK-Hep-1 derive from proteins localized in the same compartments as in lymphoid cells. Within this pool, we have identified 12 HLA class I peptides derived from HCC-related proteins. This confirms that tumor cell lines could be a good source of tumor associated antigens to be used, together with MS, to define putative epitopes for cytotoxic T cells from cancer patients.     

Irrigation infrastructure development in the Limarí Basin in Central Chile: implications for adaptation to climate variability and climate change

One option to deal with climate variability in agriculture is to build irrigation infrastructure, although this may lead to the overdevelopment of water resources, leading to ‘basin closure’. The Limarí Basin, in central north Chile, has relied on irrigation infrastructure over the last 30 years to increase water supply reliability and extend irrigated acreage, especially for permanent crops. This situation has reduced adaptation opportunities in the basin, which is currently experiencing a severe drought that, according to climate change projections, is expected to persist in the future, with important consequences for the sustainability of agriculture production.     

Robust estimation of continuous nonlinear plants with discrete measurements

In this work the problem of designing a state estimator for completely or partially observable continuous nonlinear plants with discrete measurements is addressed. The combination of a geometric approach with a stability analysis yields an estimator design methodology with a nonlinear detectability condition susceptible of testing, a systematic estimator construction, a robust convergence criterion coupled with a simple tuning scheme, as well as a rationale to explain the interplay between sampling time, estimator gains, and estimator functioning. Comparing with the continuous measurement case where the convergence is attained by tuning the gain above a low limit, in the discrete measurement case the loss of information due to the measurement sampling increases the size of the lower gain limit, and imposes sampling time and high gain limits. The proposed methodology is applied to address the estimation problem of a class of solution homopolymerization reactors, and is tested with a methyl-methacrylate polymerization run taken from a previous extended Kalman filter implementation study with experimental data.     

The role of coping in the relationship between perceived racism and racism-related stress for Asian Americans: Gender differences.

On the basis of stress and coping theory, the authors examined coping as a mediator of the relationship between perceptions of racism and racism-related stress with a sample of Asian American college students (N = 336). Results indicated that coping mediated the relationship between racism and racism-related stress differentially by gender. The more that men perceived racism, the more likely they were to use support-seeking coping strategies that were associated with higher levels of racism-related stress. The more that women perceived racism, the more they used active coping strategies that were associated with higher levels of racism-related stress. The findings demonstrate how coping with racism differs for Asian Americans on the basis of gender. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An architecture model to support cooperative design for mechatronic products: A control design case

Efficient integration of systems in the mechatronic industry is critical for complex product development and is still challenging. A particular example of this situation can be pinpointed in the development of control software for mechatronic products: design is not carried out in a concurrent way in order to exploit the synergy among domain experts and many “last minute” problems are detected and forcefully solved in the control software domain at an advanced development stage. Unfortunately, industrially applicable research to improve integration in the development process is currently at a stale. This work addresses system architecting introducing a model, a method, and a tool implementation, which aim to help changing this situation by supporting cooperative design, providing usable documentation and improving understanding of the design process by the stakeholders.     

Resonant and non-resonant microwave absorption in the magnetoelectric YCrO3 through ferro-paraelectric transition

An electron paramagnetic resonance (EPR) study in the polycrystalline magnetoelectric YCrO₃ is carried out at X-band (8.8-9.8 GHz) in the 300-510 K temperature range. For all the temperatures, the EPR spectra show a single broad line attributable to Cr³⁺ (S = 3/2) ions. The onset of the ferro-paraelectric transition has been determined from the temperature dependence of three main parameters deduced from the EPR spectra: the peak-to-peak linewidth (ΔH_pp), the integrated intensity (I_EPR) and the g-factor; these parameters indicate a behavior in agreement with a diffuse phase transition. Low-field microwave absorption (LFMA) is used to give a further knowledge on this material; where this technique also gives evidence of the ferro-paraelectric transition.