Proteome analysis of yeast response to various nutrient limitations

We compared the response of Saccharomyces cerevisiae to carbon (glucose) and nitrogen (ammonia) limitation in chemostat cultivation at the proteome level. Protein levels were differentially quantified using unlabeled and (15)N metabolically labeled yeast cultures. A total of 928 proteins covering a wide range of isoelectric points, molecular weights and subcellular localizations were identified. Stringent statistical analysis identified 51 proteins upregulated in response to glucose limitation and 51 upregulated in response to ammonia limitation. Under glucose limitation, typical glucose-repressed genes encoding proteins involved in alternative carbon source utilization, fatty acids β-oxidation and oxidative phosphorylation displayed an increased protein level. Proteins upregulated in response to nitrogen limitation were mostly involved in scavenging of alternative nitrogen sources and protein degradation. Comparison of transcript and protein levels clearly showed that upregulation in response to glucose limitation was mainly transcriptionally controlled, whereas upregulation in response to nitrogen limitation was essentially controlled at the post-transcriptional level by increased translational efficiency and/or decreased protein degradation. These observations underline the need for multilevel analysis in yeast systems biology

Energy transfer between semiconductor nanoparticles (ZnS or CdS) and Eu³⁺ ions in sol–gel derived ZrO₂ thin films

Semiconductor nanoparticles (CdS or ZnS) and Eu3+ co-doped zirconia thin films were prepared using the sol–gel route by an in situ method. We demonstrated that the energy exchange is more efficient between ZnS nanocrystals and Eu3+ ions than between CdS and Eu3+. The Eu3+ luminescence increased with the ion concentration up to 10 mol% (for 10 mol% ZnS). Moreover, the intensity of the europium emission increased as the ZnS nanoparticles concentration increased up to 15 mol% (for 5 mol% Eu3+). For The 15% ZnS–5% Eu3+ co-doped ZrO2 sample, the europium emissions were enhanced 42 times through energy transfer at 10 K. The defect states in semiconductor nanoparticles (CdS or ZnS) were found to play an important role in the energy transfer process

Human–Systems Integration Verification Principles for Commercial Space Transportation

This article presents an experience-based research effort on human–systems integration (HSI) verification principles for commercial space transportation (CST). CST HSI safety, efficiency, and comfort are analyzed with respect to four critical areas: (1) design and layout of displays and controls (we assume that displays and controls are computer based), (2) mission planning, (3) restraint and stowage, and (4) human factors in vehicle operations. HSI is analyzed using most recent approaches in human-centered design, which integrates technology, organization, and people from the very beginning of the design process and all along the life cycle of systems, including manufacturing, delivery, training, operations, and dismantling. CST HSI verification principles for the four critical areas are provided in the form of recommendations structured along with the five concepts of the AUTOS pyramid