The microscopy cell (MicCell), a versatile modular flowthrough system for cell biology, biomaterial research, and nanotechnology

We describe a novel microfluidic perfusion system for high-resolution microscopes. Its modular design allows pre-coating of the coverslip surface with reagents, biomolecules, or cells. A poly(dimethylsiloxane) (PDMS) layer is cast in a special molding station, using masters made by photolithography and dry etching of silicon or by photoresist patterning on glass or silicon. This channel system can be reused while the coverslip is exchanged between experiments. As normal fluidic connectors are used, the link to external, computer-programmable syringe pumps is standardized and various fluidic channel networks can be used in the same setup. The system can house hydrogel microvalves and microelectrodes close to the imaging area to control the influx of reaction partners. We present a range of applications, including single-molecule analysis by fluorescence correlation spectroscopy (FCS), manipulation of single molecules for nanostructuring by hydrodynamic flow fields or the action of motor proteins, generation of concentration gradients, trapping and stretching of live cells using optical fibers precisely mounted in the PDMS layer, and the integration of microelectrodes for actuation and sensing.     

Linseed oil on concrete: Penetration of linseed oil compositions into sheet-and liquid membrane-cured concretes

Penetrations of concrete specimens by solutions of boiled linseed oil in mineral spirits and emulsions of boiled linseed oil were measured. Concrete specimens were cured with polyethylene sheet (removable) and wax-based and resin-based compounds prior to penetration tests. Penetration was greatest at 35 days and least at four and seven days after curing. Penetration at 105 days was only slightly less at 35 days. Maximum penetrations were obtained with solutions more dilute than 50 volume per cent of linseed oil in mineral spirits. Penetrations on polyethylene-, wax- or resin-cured specimens varied from 1.5 to 3 mm when 50 volume per cent linseed oil solution or emulsion was spread on the specimen at the rate of 0.16 lb/yd². Presented before Committee MC-B4 at the Highway Research Board Meeting, Washington, D.C., January, 1970. No. Market. Nutr. Res. Div., ARS, USDA.     

Potential synthetic lubricants: Diol ester of C18-saturated cyclic acids

Monoalkyl esters of linseed-oil-derived C₁₈-saturated cyclic acids (HCal), described in earlier work, showed promise as lubricant base stocks for turbine aircraft as set forth in the military specification MIL-L-7808E. These esters, however, did not exhibit the increased oxidative stability and higher viscosity required by the more recent specification MIL-L-23699. Six diol esters of HCal have now been prepared. Both hindered and unhindered dihydric alcohols were used, including ethylene glycol, 1,4-cyclohexanedimethanol, 1,4-benzenedimethanol, 2,3-dimethyl-1,3-propanediol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (I). The viscosities of these esters at 210F ranged from 10.1 to 19.6 centistokes and the pour points, from −35 to −62F. Oxidative stabilities at 400F were determined with 0.5% each of phenyl-a-napthylamine (PANA) andp,p’-dioctyldiphenylamine as inhibitors. The esters of the unhindered diols had poor stability, whereas esters of the hindered diols, in particular I, exhibited excellent resistance to the formation of acidic decomposition products and sludge. Although the HCal ester of I by itself is too viscous to meet specification MIL-L-23699, its ASTM slope (0.650) is excellent. Blends of this material with less viscous hindered esters, commercially available, may find application as lubricants for high-performance turbine engines used in various aircraft. Presented at the AOCS Meeting in Los Angeles, 1966. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Influence of three non-sensory factors on consumer choice of functional yogurts over regular ones

To better understanding the consumer choice of functional foods, a choice-based conjoint study was carried out to investigate the influence of three non-sensory factors on consumer choice of functional yogurts over regular ones. Four attributes were considered in the conjoint study: type of yogurt (regular, enriched with antioxidants and enriched with fibre), brand (national familiar, national unfamiliar, and foreign familiar), price (low, regular and high) and claim (with and without ‘reduced disease risk’ health claim). Eighteen choice sets, each composed of three stimuli (regular yogurt, enriched with antioxidants and enriched with fibre and varying the brand, price and claim levels) were evaluated by 103 consumers. For each choice set, consumers had to indicate which yogurt would normally buy. A questionnaire on consumer attitude towards health and nutrition was answered by participants after the choice task. Brand, price and health claims highly significantly affected consumer choice of functional yogurts. The relative importance of brand was similar to that of type of yogurt. Therefore, results suggested that non-sensory factors such as brand and price could have an important impact on consumer perception of functional foods. The impact of brand, price and health claims was affected by consumer interest in health issues.     

Analysis of Arizona's Water Resources System

An analysis of Arizona's water resources system has been implemented. This study uses a qualitative system analysis approach to evaluate the most important components of the system: water supply, water demand, laws and regulations, stakeholders, decision makers, etc. Moreover, the investigation centres on some key components of the water resources system such as water conservation in active management areas (AMA), rural Arizona, population growth, and water rights transfers. This study provides insights on these important components, identifies factors that can be enhanced and offers suggestions for improving them. The overall goal of this analysis is to contribute ideas that will help to establish a more efficient and holistic programme to secure sustainable development of water resources.