University of Houston

Pakistani quakes leave scientists debating tech’s role.

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 In the wake of a series of large earthquakes that have struck Pakistan over the past few weeks, the country’s scientists are debating howtechnology might help limit the devastation caused by future disasters.
 
A day before the first quake, which hit southwest Pakistan on 24 September, a collaboration between US and Pakistani geoscientists was announced. The project, which has been allocated US$451,000 over three years by the US Agency for International Development, will unite researchers to study the Chaman Fault — the location of the recent earthquakes.
 

Shuhab Khan, associate professor of geology at the University of Houston, United States, is leading the US side of the project. “There have been multiple big earthquakes in the area over the last 35,000 years,” he says. “The city of Quetta is particularly in danger as it lies near the fault. Bigger earthquakes could even affect the wider area — Karachi and its surroundings, and possibly some cities in Afghanistan as well.”
 
He hopes that modern technology — including lidar, a form of radar that uses laser radiation — will help Pakistan prepare better for earthquakes.
 
“This technology has been used successfully to identify the direction of movement and major cracks in faults,” Shuhab Khan tells SciDev.Net. “So if we can use it to study the Chaman Fault, it should help Pakistan understand the risks of earthquakes better and prepare better.”
 
Currently, the Chaman Fault is one of the least studied in the world, he says.
 
Zahid Rafi, director of the National Seismic Monitoring Centre at the Pakistan Meteorological Department in Islamabad, says that he and his team have been working to improve their understanding of local seismic activity.
 
Before the devastating earthquake that struck Kashmir in 2005, Rafi says his department was using manual seismometers, but since then they have introduced automated seismometers, accelographs and GPS (global positioning systems) worth 500 million Pakistan rupees (around US$4.7 million). These are all networked with a central databank in Islamabad.
 
But Shuhab Khan remains unconvinced that the national network of seismometers set up after the 2005 quake has helped matters. “I haven’t seen much improvement in seismic research in Pakistan,” he says.
 
Asif Khan, the director of the National Centre of Excellence in Geology at the University of Peshawar, Pakistan, says the establishment of the countrywide network of seismological stations is a “healthy sign” for future earthquake mitigation measures. But there is still a “lack of seismological research and records,” he adds.
 
“Academic research was being hampered by a lack of seismic technologies. Productive research in this area needs old and new seismic data but, unfortunately, Pakistan’s old seismic data is either not reliable or of poor quality,” he says.
 
Ali Rashid Tabrez, director general of the National Institute of Oceanography in Karachi, says that “data gathering with new seismic gadgets will enable the government to create a seismic databank. This should help identify quake hot spots and seismic activity on the seabed while informing building codes and disaster management strategies.”
 
According to its ten-year National Disaster Management Plan, Pakistan’s National Disaster Management Authority is starting a US$1.4 billion project to produce national earthquake hazard maps, contingency plans and risk assessments.
 

Source: SciVx

Bismuth-carrying nanotubes track stem cells in CT.

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Texas researchers have succeeded in trapping bismuth in a nanotube cage, and the resultant structure could be used as a CT contrast agent to track stem cells, according to a new study in the Journal of Materials Chemistry B.

Specifically, the investigators from Rice University, in cooperation with the University of Houston and St. Luke’s Episcopal Hospital, are inserting bismuth compounds into single-walled carbon nanotubes to make a more effective CT contrast agent. In tests using pig bone marrow-derived mesenchymal stem cells, the researchers found that the bismuth-filled nanotubes, which they have dubbed Bi@US-tubes, produce CT images of higher attenuation than those with iodine-based contrast agents .

Bismuth has been used before as a contrast agent, but putting it in nanotube capsules allowed the researchers to get the substance inside cells in high concentrations, permitting the acquisition of CT images of the cell. The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the tubes, without compromising cell viability.

Bismuth is a heavy element and therefore is more effective at diffracting x-rays than almost any substance, according to study co-author Lon Wilson, PhD. Going forward, the nanotube surfaces can be modified to improve biocompatibility and their ability to target certain types of cells. They can also be modified for use with MRI, PET, and electron paramagnetic resonance imaging systems, he said.

The researchers are now working to double the amount of bismuth in each nanotube. They would also like to combine bismuth and gadolinium into a single nanotube to produce a bimodal contrast agent suitable for tracking in both CT and MRI, Wilson said.

Source: auntminnie.com