Emulating nature for better engineering

UK researchers describe a novel approach to making porous materials, solid foams, more like their counterparts in the natural world, including bone and wood in the new issue of the International Journal of Design Engineering.

According to Carmen Torres-Sanchez of the Department of Mechanical Engineering, at Heriot-Watt University, Edinburgh and Jonathan Corney of the Department of Design, Manufacture and Engineering Management, at the University of Strathclyde, Glasgow in the natural world, the graduated distribution of porosity has evolved so that nature might transfer forces and minimise stresses to avoid whole structure failure. For instance, a crack in the branch of a tree will not lead to the felling of the tree in the same way that a broken ankle will not lead to collapse of the whole leg. “Porosity gradation is an important functionality of the original structure that evolution has developed in a trial and error fashion,” the team explains.

It is not just tree trunks and bones that have evolved graduated porosity, beehives, marine sponges, seashells, teeth, feathers and countless other examples display this characteristic. Researchers would like to be able to emulate the way in which nature has evolved solutions to the perennial issues facing engineers. In so doing, they will be able to develop structures that use the least amount of material to gain the lowest density structure and so the maximum strength-to-weight ratio.

“Many engineering applications, such as thermal, acoustics, mechanical, structural and tissue engineering, require porosity tailored structures,” the team says. If materials scientists could develop porous materials that closely mimic nature’s structural marvels, then countless engineering problems including bridge building and construction in earthquake zones, improved vehicle and aircraft efficiency and even longer-lasting more biocompatible medical prosthetics might be possible.

Unfortunately, current manufacturing methods for making porous materials cannot mass-produce graduated foams. The collaborators in Scotland, however, have turned to low power-low frequency ultrasonic irradiation that can “excite” molten polymers as they begin to foam and once solidify effectively trap within their porous structure different porosity distributions throughout the solid matrix. This approach allowed the team to generate polymeric foams with porosity gradients closely resembling natural cellular structures, such as bones and wood. The technology opens up new opportunities in the design and manufacture of bio-mimetic materials that can solve challenging technological problems, the team adds.

The researchers anticipate that using more sophisticated ultrasound energy sources as well as chemical coupling agents in the molten starting material will allow them to fine tune the formation of pores in the material. This is an area of current interest because it would facilitate the design of novel texture distributions or replicate more closely nature porous materials, the team concludes.

Sanchez, C., & Corney, J. (2011). A novel manufacturing strategy for bio-inspired cellular structures International Journal of Design Engineering, 4 (1) DOI: 10.1504/IJDE.2011.041406

The ignored virus that causes liver cancer

Hepatitis G virus was identified in 1995. Some little research was carried out on the virus and the US Food and Drug Administration (FDA) declared it a non-harmful virus in 1997. Researchers in Saudi Arabia, writing in the International Journal of Immunological Studies present evidence to suggest that this may have been the wrong decision. They claim that transmission of the virus through donated blood that was not screened for the virus as well as infection through other routes has led to an increase in cirrhosis of the liver and liver cancer.

Hepatitis G virus (HGV) was renamed as GB virus C (GBV-C) and is a virus in the Flaviviridae family but has not yet been assigned to a genus. Intriguingly, some evidence suggests that co-infection with the AIDS virus, HIV, somehow enhances the immune system in those patients. However, it is the effects of the virus on the livers of otherwise healthy patients that is of concern to Mughis Uddin Ahmed of the King Abdulaziz Hospital (NGHA) in Al-Ahsa, Saudi Arabia. He points out that since the FDA declared the virus not to cause health problems to humans in 1997, no donated blood has been screened for this virus.

However, Mughis Uddin Ahmed has carried out a review of the scientific literature for the last 16 years that show the virus to be quite prevalent around the globe. Moreover, there is a correlation with infection with this virus and hepatitis, cirrhosis of the liver and it is possibly linked to hepatocellular carcinoma. Mughis Uddin Ahmed also found an apparent link with hematological disorders and hematological malignancies.

For this reason, he suggests that research should be carried out into this virus to determine whether it is a true human pathogen and a viral carcinogen. He also advises that screening of donated blood for this virus should be reinstated urgently rather than healthcare workers continuing to transferring the virus ignorantly to blood recipients and risking the same morbidity and mortality outcomes seen with hepatitis C virus transferred from donor to recipient until screening for that virus was adopted.

Ahmed, Q. (2011). Hepatitis G virus (HGV): where we stand and what to do? International Journal of Immunological Studies, 1 (3) DOI: 10.1504/IJIS.2011.041723

Are the French bored with wine?

UPDATE: Apparently, the Germans have lost their taste for beer! What’s best, beer or wine? There’s only one way to find out…as Harry Hill might say.

One of the most familiar aspects of French culture – its love of wine – might be lost as successive generations abandon the imaginative representations of wine linked to national identity, according to a study in the International Journal of Entrepreneurship and Small Business. The findings suggest that the transmission of French wine heritage to future generations is in terminal decline.

Consumption of wine in France is on the wane. It has fallen from the equivalent of almost 7 billion 75-cl bottles in 1980 to around 4 billion in 2008; not much more than one bottle a week per adult. The downward trend seems to be continuing with recent data predicting that just 16.5% of the adult population are now regular wine consumers.

New research from the ESC Pau research centre and Toulouse 1 Capitole University suggests that there has been a shift from regular “alimentary” wine consumption at mealtimes to drinking purely for pleasure. This has led to fewer wine drinkers overall but an increase in the number of those who drink only occasionally rather than frequently; there are fewer who insist on a bottle on the table at every meal. The demise of wine’s high status in French culture and the emergence of less favourable representations of wine, related to health issues, seems to have occurred within the last two generations, according to Pascal Poutet of the Self-development Department at ESC Pau and Thierry Lorey of ESC Pau and Capitole University.

Previous research has studied the sociological, psychological and psychoanalytical aspects of wine consumption or looked at consumption from a marketing perspective but only among younger adults. Lorey and Poutet have taken the unusual step of investigating across the generations. The researchers surveyed four groups of people those over 65 years who lived through the Second World War, the “heritage” generation, those between 40 and 65 who lived through a period of growth and worldwide development, the “baby boomers” those aged 30 to 40, “Generation X”, who grew up through the French crisis of the 1990s and those under 30, who might be labelled the “internet generation”. Each successive generation represents a general increase in libertarian attitudes and irreverence towards institutions, they suggest.

Their study revealed that all generations agree on the values of conviviality, sharing and pleasure conveyed by wine, but they differ significantly in their wine drinking habits. The over-65s are daily consumers of wine, recognise the strong social and cultural heritage and enjoy sharing the wine experience with family and friends. The two middle-aged groups are much more occasional drinkers and drink more socially with friends rather than family, social status is a factor in their wine consumption. For the under-30s, wine consumption is very much the exception rather than the rule, they rarely cite the pleasurable and social aspects of wine drinking.

“There is a dual gap between the three generations, older, middle-aged, younger,” the researchers say, “on the one hand, the consumption frequency gap (from a daily wine consumption to a festive one, and then exceptional), on the other, the pleasure gap (evolution from a genuine pleasure towards a more ostentatious pleasure, more difficult to perceive for the younger generation).” Similarly, there is an evolution across the generations of cultural reflections on wine. The older generation recognises the symbolism, tied in to French culture, history and religion. The historical factors are less of a concern for the middle-aged although they recognise the cultural and gastronomic references. For the younger generation history, religion and many of the cultural reference points are of little concern, although they do maintain great pride in wine nevertheless.

“The generational analysis of the representations of wine in France does seem to be appropriate to explain the deep changes that wine has undergone in the last 60 years,” the researchers explain. “It is precisely the progressive loss of the identity, sacred and imaginary representations of wine (nation, region, lesser importance of the transmission of the culture of wine by the father within the family, etc.) over three generations that explains France’s global consumption attitudes, and especially the steep decline in the volumes of wine consumed.”

The team suggests that a better understanding of how young adults, their parents and their grandparents might explain the links between representations of wine and its consumption and the future status of wine in France and around the world.

The representations of wine in France from generation to generation: a dual generation gap” in Int. J. Entrepreneurship and Small Business, 2011, 13, 162-180