Fluorescence Methods for Investigation of Living Cells and Microorganisms

Fluorescence methods play a leading role in the investigation of biological objects. They are the only non-destructive methods for investigating living cells and microorganisms in vivo. Using intrinsic and artificial fluorescence methods provides deep insight into mechanisms underlying physiological and biochemical processes. This book covers a wide range of modern methods involved in experimental biology. It illustrates the use of fluorescence microscopy and spectroscopy, confocal laser scanning microscopy, flow cytometry, delayed fluorescence, pulse-amplitude-modulation fluorometry, and fluorescent dye staining protocols. This book provides an overview of practical and theoretical aspects of fluorescence methods and their successful application in the investigation of static and dynamic processes in living cells and microorganisms

Mind the gap: gap factors in intercultural business communication : a study of German-Indian semi-virtual tech/engineering teams

While the affordances of technology have facilitated virtual modes of global collaboration, cultural variances and a geographically-dispersed environment can also lead to impaired group communication in team interaction. This qualitative study draws on data gathered from four organizations to investigate the miscommunication and cognitive dissonances reported by virtual German-Indian engineering/tech communities of practice. The study argues that it is not so much the performance or doing of a communicative act that creates dissonances, but the gaps, i.e., the absence or not-doing of certain communicative actions expected in a collaborative context. The gap factors are experienced as unfulfilled reciprocal expectations, and are classified and explored against three parameters: 1) the culture of a technological community of practice, 2) the power relations between the interactants, and 3) the consequences of virtual communication. The findings indicate a complementary divergence between the two groups regarding the nature of gaps. While the German teams report gaps in communicative efficiency and content caused e.g., by non-disclosure, euphemistic language and a deficiency in push communication, the Indian teams perceive gaps in relationality and affective signaling. At the same time, they are two sides of the same coin, with the divergences arising from the way in which the intersecting structural parameters are viewed as being salient in interaction. The study concludes with implications and suggestions for organizational practice

Parallel reconfigurable single photon avalanche diode array for optical communications

There is a pressing need to develop alternative communications links due to a number of physical phenomena, limiting the bandwidth and energy efficiency of wire-based systems or economic factors such as cost, material-supply reliability and environmental costs. Networks have moved to optical connections to reduce costs, energy use and to supply high data rates. A primary concern is that current optical-detection devices require high optical power to achieve fast data rates with high signal quality. The energy required therefore, quickly becomes a problem. In this thesis, advances in single-photon avalanche diodes (SPADs) are utilised to reduce the amount of light needed and to reduce the overall energy budget. Current high performance receivers often use exotic materials, many of which have severe environmental impact and have cost, supply and political restrictions. These present a problem when it comes to integration; hence silicon technology is used, allowing small, mass-producible, low power receivers. A reconfigurable SPAD-based integrating receiver in standard 130nm imaging CMOS is presented for links with a readout bandwidth of 100MHz. A maximum count rate of 58G photon/s is observed, with a dynamic range of ≈ 79dB, a sensitivity of ≈ −31.7dBm at 100MHz and a BER of ≈ 1x10−9. We investigate the properties of the receiver for optical communications in the visible spectrum, using its added functionality and reconfigurability to experimentally explore non-ideal influences. The all-digital 32x32 SPAD array, achieves a minimum dead time of 5.9ns, and a median dark count rate (DCR) of 2.5kHz per SPAD. High noise devices can be weighted or removed to optimise the SNR. The power requirements, transient response and received data are explored and limiting factors similar to those of photodiode receivers are observed. The thesis concludes that data can be captured well with such a device but more electrical energy is needed at the receiver due to its fundamental operation. Overall, optical power can be reduced, allowing significant savings in either transmitter power or the transmission length, along with the advantages of an integrated digital chip