The Simplex Algorithm for the Rapid Identification of Operating Conditions During Early Bioprocess Development: Case Studies in FAb' Precipitation and Multimodal Chromatography

This study describes a data-driven algorithm as a rapid alternative to conventional Design of Experiments (DoE) approaches for identifying feasible operating conditions during early bioprocess development. In general, DoE methods involve fitting regression models to experimental data, but if model fitness is inadequate then further experimentation is required to gain more confidence in the location of an optimum. This can be undesirable during very early process development when feedstock is in limited supply and especially if a significant percentage of the tested conditions are ultimately found to be sub-optimal. An alternative approach involves focusing solely upon the feasible regions by using the knowledge gained from each condition to direct the choice of subsequent test locations that lead towards an optimum. To illustrate the principle, this study describes the application of the Simplex algorithm which uses accumulated knowledge from previous test points to direct the choice of successive conditions towards better regions. The method is illustrated by two case studies; a two variable precipitation example investigating how salt concentration and pH affect FAb' recovery from E. coli homogenate and a three-variable chromatography example identifying the optimal pH and concentrations of two salts in an elution buffer used to recover ovine antibody bound to a multimodal cation exchange matrix. Two-level and face-centered central composite regression models were constructed for each study and statistical analysis showed that they provided a poor fit to the data, necessitating additional experimentation to confirm the robust regions of the search space. By comparison, the Simplex algorithm identified a good operating point using 50% and 70% fewer conditions for the precipitation and chromatography studies, respectively. Hence, data-driven approaches have significant potential for early process development when material supply is at a premium

Interseeded cover crops, soil health, and nitrogen supply for grain corn in Ontario

Non-Peer ReviewedInterseeded cover crops are a promising option for improving environmental sustainability in corn-based rotations. Field plots were established in 2015 under conventional tillage and regional corn N fertilization practices and repeated over two seasons at three sites in southern Ontario: Ridgetown, Elora, and Peterborough. The objectives were to evaluate the effects of interseeded annual ryegrass (ARG) and red clover (RCL) on grain corn yield and N uptake; soil mineral N (Nmin); and soil biological parameters. At each site, ARG, RCL, an ARG/RCl blend (MIX), and a no-cover control (BARE) were arranged in a RCBD replicated four times. The cover crops were seeded between the corn rows at the 5-leaf stage using an InterSeederTM drill. Cover crops accumulated 15 - 860 kg C ha-1 and 1.3 - 77 kg N ha-1 per season, and their yields were significantly correlated with soil microbial biomass, β-Glucosidase activity, and particulate organic matter. Community-level physiological profiling (BIOLOG EcoplatesTM) showed that microbial community diversity was significantly greater in ARG than BARE. Grain N concentration (10.8 - 11.2 g kg-1) and aboveground corn N uptake (100 - 154 kg ha-1) were not significantly reduced by cover crops at all sites. Although residual Nmin levels measured at grain corn harvest (0-30 cm) and the following spring (0-15 cm) were generally low (2.4 - 9.3 mg kg-1) at all sites, ARG had 48% lower Nmin than BARE. The effects of cover crops on soil health parameters, corn N uptake and Nmin were more affected by site and seasonal variability than by cover crop treatments. However, the results indicate the potential for improving soil health when there is successful establishment of interseeded annual ryegrass or red clover

Biogeochemical and Optical Analysis of Coastal DOM for Satellite Retrieval of Terrigenous DOM in the U.S. Middle Atlantic Bight

Estuaries and coastal ocean waters experience a high degree of variability in the composition and concentration of particulate and dissolved organic matter (DOM) as a consequence of riverine/estuarine fluxes of terrigenous DOM, sediments, detritus and nutrients into coastal waters and associated phytoplankton blooms. Our approach integrates biogeochemical measurements (elemental content, molecular analyses), optical properties (absorption) and remote sensing to examine terrestrial DOM contributions into the U.S. Middle Atlantic Bight (MAB). We measured lignin phenol composition, DOC and CDOM absorption within the Chesapeake and Delaware Bay mouths, plumes and adjacent coastal ocean waters to derive empirical relationships between CDOM and biogeochemical measurements for satellite remote sensing application. Lignin ranged from 0.03 to 6.6 ug/L between estuarine and outer shelf waters. Our results demonstrate that satellite-derived CDOM is useful as a tracer of terrigenous DOM in the coastal ocea

To follow a rule? On frontline clinicians’ understandings and embodiments of hospital-acquired infection prevention and control rules.

This article reports on a study of clinicians’ responses to footage of their enactments of infection prevention and control. The study’s approach was to elicit clinicians’ reflections on and clarifications about the connections among infection control activities and infection control rules, taking into account their awareness, interpretation, and in situ application of those rules. The findings of the study are that clinicians responded to footage of their own IPC practices by articulating previously unheeded tensions and constraints including: infection control rules that were incomplete, undergoing change, and conflicting; material obstructions limiting infection control efforts; and habituated and divergent rule enactments and rule interpretations that were problematic but disregarded. The reflexive process is shown to elicit clinicians’ learning about these complexities as they affect the accomplishment of effective infection control. The process is further shown to strengthen clinicians’ appreciation of infection control as necessitating deliberation to decide what are locally appropriate standards, interpretations, assumptions, habituations and enactments of infection control. The article concludes that clinicians’ ‘practical wisdom’ is unlikely to reach its full potential without video-assisted scrutiny of and deliberation about in situ clinical work. This enables clinicians to anchor their in situ enactments, reasonings and interpretations to local agreements about the intent, applicability, limits and practical enactment of rules. Key words: video-reflexivity, rules, infection control, patient safety, embodied practice, practical wisdom, abductio

Changes in persistent contaminant concentration and CYP1A1 protein expression in biopsy samples from northern bottlenose whales, Hyperoodon ampullatus, following the onset of nearby oil and gas development

Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Environmental Pollution 152 (2008): 205-216, doi:10.1016/j.envpol.2007.05.027.A small population of endangered northern bottlenose whales (Hyperoodon ampullatus) inhabits “The Gully” Marine Protected Area on the Scotian Shelf, eastern Canada. Amid concerns regarding nearby oil and gas development, we took 36 skin and blubber biopsy samples in 1996-97 (prior to major development) and 2002-03 (five years after development began), and 3 samples from a population in the Davis Strait, Labrador in 2003. These were analysed for cytochrome P4501A1 (CYP1A1) protein expression (n=36), and for persistent contaminants (n=23). CYP1A1 showed generally low expression in whales from The Gully, but higher levels during 2003, potentially co-incident with recorded oil spills, and higher levels in Davis Strait whales. A range of PCB congeners and organochlorine compounds were detected, with concentrations similar to other North Atlantic odontocetes. Concentrations were higher in whales from The Gully than from the Davis Strait, with significant increases in 4,4’-DDE and trans-nonachlor in 2002-03 relative to 1996-97.Research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada, World Wildlife Fund Canada Endangered Species Recovery Fund, Fisheries and Oceans Canada, the National Geographic Society, the Canadian Federation of Humane Societies and two U.K. Royal Society International Collaborative Awards. S.K.H. was supported by a Canadian Commonwealth Scholarship and Royal Society Dorothy Hodgkin Research Fellowship. C.D.M. was awarded a Discovery grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada. J.Y.W was supported by an NSERC PGS B fellowship and the Woods Hole Oceanographic Institution

Beyond hand hygiene: a qualitative study of the everyday work of preventing cross-contamination in hospital wards

Background Hospital-acquired infections are the most common adverse event for inpatients worldwide. Efforts to prevent microbial cross-contamination currently focus on hand hygiene and use of personal protective equipment (PPE), with variable success. Better understanding is needed of infection prevention and control (IPC) in routine clinical practice. Methods We report on an interventionist video-reflexive ethnography study that explored how healthcare workers performed IPC in three wards in two hospitals in New South Wales, Australia: an intensive care unit and two general surgical wards. We conducted 46 semistructured interviews, 24 weeks of fieldwork (observation and videoing) and 22 reflexive sessions with a total of 177 participants (medical, nursing, allied health, clerical and cleaning staff, and medical and nursing students). We performed a postintervention analysis, using a modified grounded theory approach, to account for the range of IPC practices identified by participants. Results We found that healthcare workers' routine IPC work goes beyond hand hygiene and PPE. It also involves, for instance, the distribution of team members during rounds, the choreography of performing aseptic procedures and moving ‘from clean to dirty’ when examining patients. We account for these practices as the logistical work of moving bodies and objects across boundaries, especially from contaminated to clean/vulnerable spaces, while restricting the movement of micro-organisms through cleaning, applying barriers and buffers, and trajectory planning. Conclusions Attention to the logistics of moving people and objects around healthcare spaces, especially into vulnerable areas, allows for a more comprehensive approach to IPC through better contextualisation of hand hygiene and PPE protocols, better identification of transmission risks, and the design and promotion of a wider range of preventive strategies and solutions.Funding source NHMRC APP100917

A Framework for Assessing the Solutions in Chromatographic Process Design and Operation for Large Scale Manufacture

Chromatographic separation of biopharmaceuticals is complex and tools for the prediction of performance and the trade-offs necessary for efficient operation are limited and time-consuming. This complexity is due to the large number of possible column aspect ratios that satisfy process and economic needs. This paper demonstrates a framework for the design and analysis of chromatographic steps. The functionalities are illustrated by application to a Protein A separation where the effects of column diameter, bed length and linear flow rate on cost of goods (COG/g) and productivity (g/h) are investigated so as to identify the optimal operating strategy. Results are presented as a series of ‘windows of operation’ to address key design and operating decisions. The tool allows the designer to customise limiting constraints based on product and process specific knowledge. Results indicate the significant impact on COG/g of column over-sizing and how this can be balanced by increased levels of productivity

A Framework for Assessing the Solutions in Chromatographic Process Design and Operation for Large Scale Manufacture

Chromatographic separation of biopharmaceuticals is complex and tools for the prediction of performance and the trade-offs necessary for efficient operation are limited and time-consuming. This complexity is due to the large number of possible column aspect ratios that satisfy process and economic needs. This paper demonstrates a framework for the design and analysis of chromatographic steps. The functionalities are illustrated by application to a Protein A separation where the effects of column diameter, bed length and linear flow rate on cost of goods (COG/g) and productivity (g/h) are investigated so as to identify the optimal operating strategy. Results are presented as a series of ‘windows of operation’ to address key design and operating decisions. The tool allows the designer to customise limiting constraints based on product and process specific knowledge. Results indicate the significant impact on COG/g of column over-sizing and how this can be balanced by increased levels of productivity

Should I stay or should I go? Patient understandings of and responses to source-isolation practices,

Isolation of patients, who are colonised or infected with a multidrug-resistant organism (source-isolation), is a common practice in most acute health-care settings, to prevent transmission to other patients. Efforts to improve the efficacy of source-isolation in hospitals focus on healthcare staff compliance with isolation precautions. In this article we examine patients’ awareness, understandings and observance of source-isolation practices and directives with a view to understanding better the roles patients play or could play in transmitting, or limiting transmission, of multidrug-resistant organisms (MRO). Seventeen source-isolated adult surgical patients and two relatives participated in video-reflexive ethnography and interviews. We learned that, although most of these patients wanted to protect themselves and others from colonisation/infection with a MRO, they had a limited understanding of what precautions they could take while in isolation and found it difficult to obtain ongoing information. Thus, many patients regularly left their source-isolation rooms without taking appropriate precautions and were potentially contributing to environmental contamination and transmission. Some patients also interacted with other patients and their personal belongings in ways that exposed other patients, unnecessarily, to colonisation/infection risk. By not providing patients with adequate information on infection risk or how they could contribute to their own safety or that of others, they are denied the opportunity to fully engage in their healthcare. To improve the efficacy of source-isolation and contact precautions in general, patient care providers should consider colonised or infected patients as active partners in reducing transmission and involve patients and relatives in regular, ongoing conversations about transmission prevention.Keywords: Patient involvement, patient experience, patient engagement, patient- and family-centred care, source-isolation, MRSA, infection prevention and control, qualitative methods, health literacyThis study was funded by the National Health and Medical Research Council (project grant # 1009178

Enhanced He-alpha emission from "smoked" Ti targets irradiated with 400nm, 45 fs laser pulses

We present a study of He-like 1s(2)-1s2p line emission from solid and low-density Ti targets under similar or equal to 45 fs laser pulse irradiation with a frequency doubled Ti: Sapphire laser. By varying the beam spot, the intensity on target was varied from 10(15) W/cm(2) to 10(19) W/cm(2). At best focus, low density "smoked" Ti targets yield similar to 20 times more He-alpha than the foil targets when irradiated at an angle of 45 degrees with s-polarized pulses. The duration of He-alpha emission from smoked targets, measured with a fast streak camera, was similar to that from Ti foils