Formulation Improvements in the Applications of Surfactant–Oil–Water Systems Using the HLDN Approach with Extended Surfactant Structure

Soap applications for cleaning and personal care have been used for more than 4000 years, dating back to the pharaonic period, and have widely proliferated with the appearance of synthetic surfactants a century ago. Synthetic surfactants used to make macro-micro-nano-emulsions and foams are used in laundry and detergency, cosmetics and pharmaceuticals, food conditioning, emulsified paints, explosives, enhanced oil recovery, wastewater treatment, etc. The introduction of a multivariable approach such as the normalized hydrophilic–lipophilic deviation (HLD N) and of specific structures, tailored with an intramolecular extension to increase solubilization (the so-called extended surfactants), makes it possible to improve the results and performance in surfactant–oil–water systems and their applications. This article aims to present an up-to-date overview of extended surfactants. We first present an introduction regarding physicochemical formulation and its relationship with performance. The second part deals with the importance of HLD N to make a straightforward classification according to the type of surfactants and how formulation parameters can be used to understand the need for an extension of the molecule reach into the oil and water phases. Then, extended surfactant characteristics and strategies to increase performance are outlined. Finally, two specific applications, i.e., drilling fluids and crude oil dewatering, are described.

Embryonic Methamphetamine Exposure Inhibits Methamphetamine Cue Conditioning and Reduces Dopamine Concentrations in Adult N2 Caenorhabditis elegans

Methamphetamine (MAP) addiction is substantially prevalent in today's society, resulting in thousands of deaths and costing billions of dollars annually. Despite the potential deleterious consequences, few studies have examined the long-term effects of embryonic MAP exposure. Using the invertebrate nematode Caenorhabditis elegans allows for a controlled analysis of behavioral and neurochemical changes due to early developmental drug exposure. The objective of the current study was to determine the long-term behavioral and neurochemical effects of embryonic exposure to MAP in C. elegans. In addition, we sought to improve our conditioning and testing procedures by utilizing liquid filtration, as opposed to agar, and smaller, 6-well testing plates to increase throughput. Wild-type N2 C. elegans were embryonically exposed to 50 μM MAP. Using classical conditioning, adult-stage C. elegans were conditioned to MAP (17 and 500 μM) in the presence of either sodium ions (Na+) or chloride ions (Cl-) as conditioned stimuli (CS+/CS-). Following conditioning, a preference test was performed by placing worms in 6-well test plates spotted with the CS+ and CS- at opposite ends of each well. A preference index was determined by counting the number of worms in the CS+ target zone divided by the total number of worms in the CS+ and CS- target zones. A food conditioning experiment was also performed in order to determine whether embryonic MAP exposure affected food conditioning behavior. For the neurochemical experiments, adult worms that were embryonically exposed to MAP were analyzed for dopamine (DA) content using high-performance liquid chromatography. The liquid filtration conditioning procedure employed here in combination with the use of 6-well test plates significantly decreased the time required to perform these experiments and ultimately increased throughput. The MAP conditioning data found that pairing an ion with MAP at 17 or 500 μM significantly increased the preference for that ion (CS+) in worms that were not pre-exposed to MAP. However, worms embryonically exposed to MAP did not exhibit significant drug cue conditioning. The inability of MAP-exposed worms to condition to MAP was not associated with deficits in food conditioning, as MAP-exposed worms exhibited a significant cue preference associated with food. Furthermore, our results found that embryonic MAP exposure reduced DA levels in adult C. elegans, which could be a key mechanism contributing to the long-term effects of embryonic MAP exposure. It is possible that embryonic MAP exposure may be impairing the ability of C. elegans to learn associations between MAP and the CS+ or inhibiting the reinforcing properties of MAP. However, our food conditioning data suggest that MAP-exposed animals can form associations between cues and food. The depletion of DA levels during embryonic exposure to MAP could be responsible for driving either of these processes during adulthood.

Visitor awareness of brown bear (Ursus arctos) human-food conditioning in Bieszczady and Tatra National Parks (Carpathians, Poland)

This paper investigates the awareness of visitors to Bieszczady National Park (BNP) and Tatra National Park (TNP) of human influence on brown bears (Ursus arctos Linnaeus, 1758), i.e. what causes human-habituated bears to become food-conditioned. In the parks studied, 928 questionnaires were collected in July and August 2007. The survey was supplemented with data on the amount of garbage collected in both parks by municipal services in 2007. Respondents in BPN displayed significantly greater knowledge about the causes of human-food conditioning of bears than respondents in TNP (64.2% and 52.7%, respectively, had more than the average of 3.54 correct answers per 5 questions in the questionnaire). As many as 60.1% of visitors in both parks incorrectly associated human-food conditioning with a lack of natural food and 34.4% withan excessive number of bears. Most respondents did not realise that to prevent human-bear conflict, decisive actions must be taken towards every food conditioned bear observed in the free-living population. Unlike in BNP, in TNP there is a large amount of rubbish left by visitors along trails. In 2007, municipal services collected in both parks a similar amount of garbageper 1000 visitors (0.39 m3 and 0.37 m3 in BNP and TNP, respectively) but the annual number of visitors is nearly 8‑fold lower inBNP than in TNP. In BNP, only visitors put rubbish in containers, while in TNP, additional 6 cleaning companies are employed to collect rubbish thrown by visitors along trails. In contrast to TNP, however, in BNP there are no bear-proof containers. Both parks need to prevent the access of bears to rubbish. It is also advisable to initiate an effective information campaign among visitors about prevention of human-food conditioning of bears.