The Varied Role of Efflux Pumps of the MFS Family in the Interplay of Bacteria with Animal and Plant Cells

Efflux pumps represent an important and large group of transporter proteins found in all organisms. The importance of efflux pumps resides in their ability to extrude a wide range of antibiotics, resulting in the emergence of multidrug resistance in many bacteria. Besides antibiotics, multidrug efflux pumps can also extrude a large variety of compounds: Bacterial metabolites, plant-produced compounds, quorum-sensing molecules, and virulence factors. This versatility makes efflux pumps relevant players in interactions not only with other bacteria, but also with plant or animal cells. The multidrug efflux pumps belonging to the major facilitator superfamily (MFS) are widely distributed in microbial genomes and exhibit a large spectrum of substrate specificities. Multidrug MFS efflux pumps are present either as single-component transporters or as tripartite complexes. In this review, we will summarize how the multidrug MFS efflux pumps contribute to the interplay between bacteria and targeted host cells, with emphasis on their role in bacterial virulence, in the colonization of plant and animal host cells and in biofilm formation. We will also address the complexity of these interactions in the light of the underlying regulatory networks required for the effective activation of efflux pump genes

A piezoelectric micropump based on micromachining of silicon

The design and realization of two pumps based on micromachining of silicon are described. The pumps, which are of the reciprocating displacement type, comprise one or two pump chambers, a thin glass pump membrane actuated by a piezoelectric disc and passive silicon check valves to direct the flow. Chambers, channels and valves are realized in a silicon wafer by wet chemical etching. The results of mechanical calculations and simulations show good agreement with the actual behaviour of the pumps. It is possible to design pumps having a specific yield and pressure dependence, and which are fail-safe (the flow is blocked while the pump is switched off)

Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors

A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and non-evaporable getter pumps has been developed and used to create a cold atomic sample in a chamber that operates with only passive vacuum pumps. The ion-mass spectrum of evaporated gases from the alkali metal dispenser has been recorded as a function of dispenser current. The efficacy of the non-evaporable getter pumps in promoting and maintaining vacuum has been characterized by observation of the Rb vapor optical absorption on the D2 transition at 780 nm and vacuum chamber pressure rate of rise tests. We have demonstrated a sample of laser-cooled Rb atoms in this chamber when isolated and operating without active vacuum pumps

Domestic heat pumps

Bakalářská práce se zabývá tepelnými čerpadly pro rodinný dům. Je rozdělena na dvě základní části. V první části je popsán princip fungování tepelného čerpadla, jeho součásti a různé typy. Jsou zde také zmíněny jednotlivé druhy nízkopotenciálních zdrojů energie včetně charakteristických vlastností a vzájemného srovnání. V druhé části je řešen návrh tepelného čerpadla pro určitý rodinný dům. Součástí projektu je navržení konkrétního tepelného čerpadla, vrtu a výpočet množství tepla potřebného pro vytápění a přípravu teplé vody. V závěru je uvedena celková ekonomická bilance včetně návratnosti investice.The Bachelor´s Thesis deals with domestic heat pumps. It is devided into two basic parts. In the first part, an operating principle, components and various types are described. Particular kinds of low-energy sources including characteristical features and comparision are mentioned there as well. In the second part, a project for a domestic heat pump is prepared. The project includes proposition of a particular heat pump, a borehole and an amount of heat needed for heating and a preparation of warm water. At the end, a complete economical balance including an economic return of the investment is mentioned.

High pressure liquid gas pump

Design and development of two types of pumps for handling liquefied gases are discussed. One pump uses mechanical valve shift and other uses pneumatic valve shift. Illustrations of pumps are provided and detailed description of operation is included

Transport and Dissipation in Quantum Pumps

This paper is about adiabatic transport in quantum pumps. The notion of ``energy shift'', a self-adjoint operator dual to the Wigner time delay, plays a role in our approach: It determines the current, the dissipation, the noise and the entropy currents in quantum pumps. We discuss the geometric and topological content of adiabatic transport and show that the mechanism of Thouless and Niu for quantized transport via Chern numbers cannot be realized in quantum pumps where Chern numbers necessarily vanish.Comment: 31 pages, 10 figure