Das IT-Sicherheitsgesetz

Datenschutz und Datensicherheit - DuD - Die öffentliche Sicherheit zählt zu den wichtigsten Aufgaben der Innenpolitik. Dazu gehören der Schutz der Bürgerinnen und Bürger...     

Development in refrigeration: technical advances and opportunities for the 1990s

The world-wide of refrigeration applications is the result of expanding markets, international competition and improved products based on advanced technology. This plenary lecture outlines the potential impact of technical advances in solid-state microelectronics and computers, new working fluids and space-age structural materials on refrigeration products of the 1990s. Future equipment developments that are reviewed include advanced compressors, solid-state drives, desiccant cooling systems and products such as engine-driven and Stirling heat pumps. Environmental impact of CFCs and the recent breakthroughs in superconducting materials are likely to create both disruptions and opportunities for refrigeration in the next decade.

Résumé

The world-wide of refrigeration applications is the result of expanding markets, international competition and improved products based on advanced technology. This plenary lecture outlines the potential impact of technical advances in solid-state microelectronics and computers, new working fluids and space-age structural materials on refrigeration products of the 1990s. Future equipment developments that are reviewed include advanced compressors, solid-state drives, desiccant cooling systems and products such as engine-driven and Stirling heat pumps. Environmental impact of CFCs and the recent breakthroughs in superconducting materials are likely to create both disruptions and opportunities for refrigeration in the next decade.     

HFC 134a as a substitute refrigerant for CFC 12

In response to international protocol agreements and national regulatory actions promoted by the increasing concern for ozone depletion and the greenhouse effect, HFC 134a has emerged as a leading candidate for CFC 12 substitution in automotive air conditioners, centrifugal chillers and residential refrigerators and freezers. This Paper discusses compressor and refrigeration system requirements and information gaps for HFC 134a application as a CFC 12 substitute.     

A hyperprostaglandin E syndrome mutation in Kir1.1 (renal outer medullary potassium) channels reveals a crucial residue for channel function in Kir1.3 channels

Loss of function mutations in kidney Kir1.1 (renal outer medullary potassium channel, KCNJ1) inwardly rectifying potassium channels can be found in patients suffering from hyperprostaglandin E syndrome (HPS), the antenatal form of Bartter syndrome. A novel mutation found in a sporadic case substitutes an asparagine by a positively charged lysine residue at amino acid position 124 in the extracellular M1-H5 linker region. When heterologously expressed in Xenopus oocytes and mammalian cells, current amplitudes from mutant Kir1.1a[N124K] channels were reduced by a factor of approximately 12 as compared with wild type. A lysine at the equivalent position is present in only one of the known Kir subunits, the newly identified Kir1.3, which is also poorly expressed in the recombinant system. When the lysine residue in guinea pig Kir1.3 (gpKir1.3) isolated from a genomic library was changed to an asparagine (reverse HPS mutation), mutant channels yielded macroscopic currents with amplitudes increased 6-fold. From single channel analysis it became apparent that the decrease in mutant Kir1.1 channels and the increase in mutant gpKir1.3 macroscopic currents were mainly due to the number of expressed functional channels. Coexpression experiments revealed a dominant-negative effect of Kir1.1a[N124K] and gpKir1.3 on macroscopic current amplitudes when coexpressed with wild type Kir1.1a and gpKir[K110N], respectively. Thus we postulate that in Kir1.3 channels the extracellular positively charged lysine is of crucial functional importance. The HPS phenotype in man can be explained by the lower expression of functional channels by the Kir1. 1a[N124K] mutant.