Microflow Cytometers with Integrated Hydrodynamic Focusing

This study demonstrates the suitability of microfluidic structures for high throughput blood cell analysis. The microfluidic chips exploit fully integrated hydrodynamic focusing based on two different concepts: Two-stage cascade focusing and spin focusing (vortex) principle. The sample—A suspension of micro particles or blood cells—is injected into a sheath fluid streaming at a substantially higher flow rate, which assures positioning of the particles in the center of the flow channel. Particle velocities of a few m/s are achieved as required for high throughput blood cell analysis. The stability of hydrodynamic particle positioning was evaluated by measuring the pulse heights distributions of fluorescence signals from calibration beads. Quantitative assessment based on coefficient of variation for the fluorescence intensity distributions resulted in a value of about 3% determined for the micro-device exploiting cascade hydrodynamic focusing. For the spin focusing approach similar values were achieved for sample flow rates being 1.5 times lower. Our results indicate that the performances of both variants of hydrodynamic focusing suit for blood cell differentiation and counting. The potential of the micro flow cytometer is demonstrated by detecting immunologically labeled CD3 positive and CD4 positive T-lymphocytes in blood

Exploring Strategy Implementation Consistency Over Time: The Moderating Effects of Industry Velocity and Firm Performance

In this paper we empirically investigate the temporal development of a firm’s strategy implementation consistency (SIC), i.e. the alignment between firms’ resource allocation decisions (RAD) and their articulated corporate concept (Noda and Bower, 1996; Burgelman and Grove, 1996; Love et al., 2002; Mintzberg, 1978). Doing so, we test whether (1) SIC is more likely to increase or decline over time, (2) whether firms competing in (low) high-velocity environments in fact show different temporal patterns in SIC, and (3) whether overperforming firms succeed in conserving their level of SIC. For our analysis we draw on 6238 RAD of 20 publicly listed firms with European origin over a period of 4–6 years. Applying maximum likelihood ordered logit estimation, our results indicate that the likelihood of an alignment of RAD and a firm’s corporate concept decreases over time. In line with scholars’ perception of high-velocity environments, we find that the firms in our sample competing under such conditions show no clear trend in SIC. These firms tend to “zig-zag” over time – swaying off and pulling back to their strategic course independent of the timing of the announcement of a corporate concept. We also find that overperforming firms are unsuccessful in preserving their SIC at the same level over time. Based on the empirical findings the paper discusses implications for theory and derives suggestions for corporate level managers on how to balance SIC and strategic flexibility. Copyright Springer 2006corporate concept, resource allocation decisions, strategy formation, strategy implementation consistency,