A comparative study of workstation partitions in an existing side-lit open plan office with daylight results using annual climate-based simulations

Workstation partitions are used in open plan offices for many reasons and come in a wide variety of materials, types, and shapes. The position, height, and orientation of partitions affect the amount and distribution of daylight entering a building as well as all forms of thermal transfer through windows. However, these potential impacts cannot be determined if not adequately addressed in guidelines and standards, and could mislead decision-making during design stages and hamper the refinement of office furniture manufacturing. This study outlines the daylight performance of workstation partition alternatives in a large open plan office on the 11th floor of a high-rise building located in downtown Raleigh, NC. For this purpose, 60 alternate combinations of workstation partitions including partition materials, layouts, heights, and orientations in four daylight zones (north, south, east, and west) were conducted using Radiance engine V.4.2.0. These combinations were analyzed based on two recently recommended annual climate-based daylighting metrics and performance criteria proposed by Illuminating Engineering Society (IES) 2012, spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE), to evaluate the feasibility and potential effectiveness of workstation partition design. Findings indicate that partition material, height, orientation, and layout have robust impacts on daylight sufficiency and the risk of daylight excessiveness. Annual daylighting simulation results report that sDA values in this study space range between 46.6% and 84%, and ASE differs by 10.6% to 15.2%. It is also revealed that the highest annual daylight sufficiency values and the lowest daylight excessiveness belong to those partitions oriented perpendicular to windows based on spine layout. Exploring these alternatives in detail helps draw attention to the possible partition layouts that are both effective and economical to overcome glare and visually uncomfortable conditions in open plan offices. More widespread application of daylight-based partition design in open plan offices could result in a better understanding of their performances, as well as improvements in their overall efficiency. These improvements could provide a comfortable, productive and healthy environment for occupants as well as savings in annual energy consumption

A Naturally Occurring Mutation in ropB Suppresses SpeB Expression and Reduces M1T1 Group A Streptococcal Systemic Virulence

Epidemiological studies of group A streptococcus (GAS) have noted an inverse relationship between SpeB expression and invasive disease. However, the role of SpeB in the course of infection is still unclear. In this study we utilize a SpeB-negative M1T1 clinical isolate, 5628, with a naturally occurring mutation in the gene encoding the regulator RopB, to elucidate the role of RopB and SpeB in systemic virulence. Allelic exchange mutagenesis was used to replace the mutated ropB allele in 5628 with the intact allele from the well characterized isolate 5448. The inverse allelic exchange was also performed to replace the intact ropB in 5448 with the mutated allele from 5628. An intact ropB was found to be essential for SpeB expression. While the ropB mutation was shown to have no effect on hemolysis of RBC's, extracellular DNase activity or survival in the presence of neutrophils, strains with the mutated ropB allele were less virulent in murine systemic models of infection. An isogenic SpeB knockout strain containing an intact RopB showed similarly reduced virulence. Microarray analysis found genes of the SpeB operon to be the primary target of RopB regulation. These data show that an intact RopB and efficient SpeB production are necessary for systemic infection with GAS