1,354,559 research outputs found
Kelly-Springfield truck hauling logs, ca. 1925
No full textLogging companies sometimes built railroads to haul logs out of the forest. Later, they used trucks. This photo was taken in the mid-1920s, somewhere in western Washington. A Kelly-Springfield logging truck hauls a large fir log along a track-like wooden logging road. Behind the truck are acres of cutover land. Wood was used for roads because it was cheap and there was plenty of it.
This photo was taken in the mid-1920s by Bellingham photographer J. Wilbur Sandison and copied a few years later by Webster & StevensOriginal photograph: Sandison, J. Wilbur, ca. 1925. Copied about 1929 by Webster & Stevens1 nitrate negative: b&w; 8 x 10 in
Curriculum 2000 : the relationship between course choice and career aspirations
No full textThis study explores factors influencing choices of AS and A2 courses, and post-18 progression pathways, made by the first Curriculum 2000 cohort of students in a large sixth form college in Hampshire. A high proportion of students in this college studied four or five AS levels and many chose at least one subject which they had not studied before. Data from the College's management information system were analysed to identify and track 544 students' changing preferences for A2 courses, as stated in March and June of their first year of study, together with final choices made in the second year. Reasons for choices, and changes to these, were explored in interviews with 19 students. A questionnaire survey, conducted in January of their second year of study, was completed by 328 students. This explored reasons for changes to post-18 progression aims which had occurred since September of their first year. Statistical analysis allowed possible links between changes in progression aims and changes to A2 course choices to be identified. Key findings are the high degree of instability in students' choices of A2 courses, and the primacy of enjoyment and perceived potential for success in choice of subjects. It also emerged that, once they had made their A2 choices, many students prioritised between AS courses in an effort to manage workload. The influence of parental advice, both on course choices and on progression aims, was also found to be significant. The experience of studying subjects at AS level emerged as a very strong influence on choice of post-18 destination, as students took advantage of the greater flexibility afforded by Curriculum 2000 to delay, or change, career decisions. Implications and recommendations for student guidance are suggested by the study.</p
Kelly-Springfield truck hauling logs, ca. 1925
No full textBy the late 1920s, many logging companies had started using trucks to haul logs out of the forest and down to the sawmill. This photo was taken in the mid-1920s, somewhere in western Washington. A Kelly-Springfield truck hauls a load of fir logs along a logging road.
This photo was taken in the mid-1920s by Bellingham photographer J. Wilbur Sandison and copied a few years later by Webster & StevensOriginal photograph: Sandison, J. Wilbur, ca. 1925. Copied about 1929 by Webster & Stevens1 nitrate negative: b&w; 8 x 10 in
Microfluidic array platform for simultaneous lipid bilayer membrane formation
No full textIn recent years, protein array technologies have found widespread applications in proteomics. However, new methods for high-throughput analysis of protein-protein and protein-compound interactions are still required. In this paper, an array of lipid bilayer membranes formed within a microfluidic system with integrated electrodes is presented. The system is comprised of three layers that are clamped together, thus rendering the device cleanable and reusable. The device microfluidics enable the simultaneous formation of an array of lipid bilayers using a previously developed air-exposure technique, thereby avoiding the need to manually form individual bilayers. The Ag/AgCl electrodes allow for ion channel measurements, each of the sites being independently addressable. Typically, a 50% yield in simultaneous lipid bilayer formation over 12 sites was obtained and ion channel recordings have been acquired over multiple sites. This system has great potential for the development of an automatable platform of suspended lipid bilayer array
Polymer microfluidic devices for the formation and investigation of artificial bilayer lipid membrane (BLM) systems
No full textA polymer microfluidic device for the formation of artificial bilayer lipid membranes (BLMs) on-chip is described. Using rapid fabrication techniques, devices were produced from thin, transparent polymeric films, so as to enable simulataneous optical and electrical monitoring of BLMs. BLMs have been successfully produced within the device
Air-Exposure Technique for the Formation of Artificial Lipid Bilayers in Microsystems
No full textTo develop a reliable method for on-chip bilayer lipid membrane (BLM) formation, which could be employed for use in a biosensor array platform, a polymer microfluidic device has been constructed, and the formation of suspended BLMs within it has been investigated. A simple, yet reproducible BLM formation protocol has been developed, in which a brief air-exposure period is employed to induce the rapid thinning of an initially thick lipid-solvent layer. The technique is rapid, reproducible, and amenable to the simple injection of proteins or analytes, as well as to buffer exchange on both sides of the membrane. Scaling up the technique for use in an array platform is also straightforward, the simultaneous formation of three individually addressable BLMs being demonstrated
Controlled delivery of membrane proteins to artificial lipid bilayers by nystatin-ergosterol modulated vesicle fusion
No full textThe study of ion channels and other membrane proteins and their potential use as biosensors and drug screening targets require their reconstitution in an artificial membrane. These applications would greatly benefit from microfabricated devices in which stable artificial lipid bilayers can be rapidly and reliably formed. However, the amount of protein delivered to the bilayer must be carefully controlled. A vesicle fusion technique is investigated where composite ion channels of the polyene antibiotic nystatin and the sterol ergosterol are employed to render protein-carrying vesicles fusogenic After fusion with an ergosterol-free artificial bilayer the nystatin-ergosterol channels do not dissociate immediately and thus cause a transient current signal that marks the vesicle fusion event. Experimental pitfalls of this method were identified, the influence of the nystatin and ergosterol concentration on the fusion rate and the shape of the fusion event marker was explored, and the number of different lipid was reduced. Under these conditions, the B-amyloid peptide could be delivered in a controlled manner to a standard planar bilayer. Additionally, the electrical recordings were obtained of vesicles fusing with a planar lipid bilayer in a microfabricated device, demonstrating the suitability of nystatin-ergosterol modulated vesicle fusion for protein delivery within microsystems
Proliferating cell nuclear antigen: A marker of limited utility for proliferation studies in liver metastases?
No full textBilayer lipid membranes from falling droplets
No full textWe describe a system that provides a rapid and simple way of forming suspended lipid bilayers within a microfluidic platform from an aqueous droplet. Bilayer lipid membranes are created in a polymeric device by contacting monolayers formed at a two-phase liquid-liquid interface. Microdroplets, containing membrane proteins, are injected onto an electrode positioned above an aperture machined through a conical cavity that is filled with a lipid-alkane solution. The formation of the BLM depends solely on the device geometry and leads to spontaneous formation of lipid bilayers simply by dispensing droplets of buffer. When an aqueous droplet containing transmembrane proteins or proteoliposomes is injected, straightforward electrophysiology measurements are possible. This method is suitable for incorporation into lab-on-a-chip devices and allows for buffer exchange and electrical measurements
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