ACS Chemistry for Life

“Milking” microscopic algae could yield massive amounts of oil
Industrial & Engineering Chemistry Research

Richard Gordon, T. V. Ramachandra, Durga Madhab Mahapatra, and Karthick Band note that some geologists believe that much of the world’s crude oil originated in diatoms, which produce an oily substance in their bodies. Barely one-third of a strand of hair in diameter, diatoms flourish in enormous numbers in oceans and other water sources. They die, drift to the seafloor, and deposit their shells and oil into the sediments. Estimates suggest that live diatoms could make 10-200 times as much oil per acre of cultivated area compared to oil seeds, Gordon says. “We propose ways of harvesting oil from diatoms, using biochemical engineering and also a new solar panel approach that utilizes genetically modifiable aspects of diatom biology, offering the prospect of “milking” diatoms for sustainable energy by altering them to actively secrete oil products,” the scientists say. “Secretion by and milking of diatoms may provide a way around the puzzle of how to make algae that both grow quickly and have a very high oil content.”

Study advises Chinese government to change fuel in millions of households
Environmental Science & Technology

Yingjun Chen and colleagues are recommending that the Chinese government consider phasing out the direct burning of traditional chunks of coal in millions of households. Their report suggests that the government substitute coal briquettes and improved stoves for cooking and heating to help reduce the country’s high air pollution levels. Studies indicate that emissions from incomplete coal combustion in these stoves contribute significantly to China’s serious air pollution levels – among the highest in the world. The scientists compared emissions between traditional and improved stoves using either raw (unprocessed) coal chunks or coal briquettes. The briquettes consist of coal powder and clay and are molded into multihole columns. They found that burning briquettes in well-ventilated stoves dramatically reduced black carbon emissions by 98 percent and other emissions by more than 60 percent.

First opal-like crystals discovered in meteorite
Journal of the American Chemical Society

Scientists have found opal-like crystals in the Tagish Lake meteorite, which fell to Earth in Canada in 2000. This is the first extraterrestrial discovery of these unusual crystals, which may have formed in the primordial cloud of dust that produced the sun and planets of our solar system 4.6 billion years ago. Katsuo Tsukamoto and colleagues say that colloidal crystals such as opals, which form as an orderly array of particles, are of great interest for their potential use in new electronics and optical devices. Surprisingly, the crystals in the meteorite are composed of magnetite, which scientists thought could not assemble into such a crystal because magnetic attractions might pack the atoms together too tightly. “We believe that, if synthesized, magnetite colloidal crystals have promising potential as a novel functional material,” the article notes.

Denver to Barcelona: Global cities and greenhouse gas emissions
Environmental Science & Technology

Christopher Kennedy and colleagues note in the new study that some cities are developing strategies to reduce releases of GHG, which include carbon dioxide, methane, and other gases that can contribute to global warming through the greenhouse effect. Denver released the largest amount of greenhouse gases (GHG) and Barcelona the smallest amount in their study documenting how differences in climate, population density and other factors affect GHG emissions in global cities. Denver had the highest overall GHG emissions, with levels two to five times higher than other cities. Its high levels were due partly to its high use of electricity, heating and industrial fuels, and ground transportation, they note. Los Angeles was second on the list, followed by Toronto and Cape Town (tied for third), Bangkok, New York City, London, Prague, Geneva, and Barcelona.

“Super sand” for better purification of drinking water
ACS Applied Materials & Interfaces

Mainak Majumder and colleagues have developed a way to transform ordinary sand – a mainstay filter material used to purify drinking water throughout the world – into a “super sand” with five times the filtering capacity of regular sand. The new material could be a low-cost boon for developing countries, where more than a billion people lack clean drinking water. The researchers used a simple method to coat sand grains with graphite oxide (GO), creating a super sand that successfully removed mercury and a dye molecule from water. In the mercury test, ordinary sand was saturated within 10 minutes of filtration, while the super sand absorbed the heavy metal for more than 50 minutes, the scientists discovered. Its filtration “performance is comparable to some commercially available activated carbon,” the scientists said. “We are currently investigating strategies that will enable us to assemble functionalized GO particles on the sand grains to further enhance contaminant removal efficiencies,” they write.

Recycling: A new source of indispensible “rare earth” materials mined mainly in China
Environmental Science & Technology

Xiaoyue Du and Thomas E. Graedel note that the dozen-plus rare earth elements (REEs) have unique physical and chemical properties making them essential for defense applications, computers, cell phones, electric vehicles, batteries, appliances, fertilizers, liquid crystal displays, and other products. But there is growing concern about the supply, since only one country, China, is the major source. To determine how much recycling potential of the REEs from in-use products could add to the supply, they did the first analysis of the amount of REEs available in products in major user countries: the United States, Japan, and China. The analysis concluded that nearly 99,000 tons of REEs were included in products in 2007. This invisible stock, equivalent to more than 10 years of production, “suggests that REE recycling may have the potential to offset a significant part of REE virgin extraction in the future…and minimize the environmental challenges present in REE mining and processing,” the report notes.

Pinpointing the origin of corpses, fingering fake cheese, and more – with “isoscapes”
Chemical & Engineering News

An emerging field of science termed “isoscapes” is making it possible to pinpoint the geographical origins of illegal drugs, trafficked endangered animals, dismembered human body parts at crime scenes, and even pricey scotch whiskey and cheese. Sarah Everts, C&EN European correspondent, explains how isoscapes has even led to development of one of the newest and most unusual maps of the world. It is a map showing the isotope contours of the world, which scientists and others are using in tracking the geographical origins of objects, and even in research on global climate change. Identification by isoscapes is based on the discovery that the tissue in a person’s body and composition of drugs, whiskey, and other objects contains a distinctive isotope ratio “fingerprint.” That fingerprint stems from the isotope ratios of food, water, and air where the person, whiskey and other objects originated, which vary with geography that can be plotted on a map. The article explains how the isotope-based map can help convict murderers and authenticate the origins of fancy foods.

Safety testing on Gulf seafood
Chemical & Engineering News

Government assurances that seafood from the Gulf of Mexico is safe to eat after the Deepwater Horizon oil spill are the result of a monitoring and testing program that continues more than a year after the April 20, 2010 disaster. C&EN Senior Correspondent Ann Thayer points out that U. S. Food and Drug Administration (FDA) officials say ongoing tests consistently show amounts of potentially toxic substances in seafood 100 to 1,000 times smaller than those posing health concerns. Thayer describes how FDA worked on an urgent basis with the National Oceanic and Atmospheric Administration and state agencies to set up the monitoring program, which used approaches that ranged from sniff tests to sophisticated laboratory analysis. The results underpinned decisions by Federal and state authorities on closing and reopening Gulf fisheries. Officials allowed a gradual reopening of Gulf waters, with the final sector declared safe in April 2011. Safety monitoring continues and despite the reassuring results, safety concerns linger among some scientists and consumers, the article indicates.

Getting more anti-cancer medicine into the blood
Langmuir

Yuri M. Lvov and colleagues are reporting successful application of the technology used in home devices to clean jewelry, dentures, and other items to make anticancer drugs like tamoxifen and paclitaxel dissolve more easily in body fluids, so they can better fight the disease. Many drugs, including some of the most powerful anti-cancer medications, have low solubility in water, meaning they do not dissolve well. IV administration of large amounts can lead to clumping that blocks small blood vessels, so doses sometimes must be kept below the most effective level. The scientists describe using sonication, high-pitched sound waves like those in home ultrasonic jewelry and denture cleaners, to break anti-cancer drugs into particles so small that thousands would fit across the width of a human hair. Each particle then gets several coatings with natural polysaccharides that keep them from sticking together. The technique, termed nanoencapsulation, worked with several widely used anti-cancer drugs, raising the possibility that it could be used to administer more-effective doses of the medications.

Vegans’ elevated heart risk requires omega-3s and B12
Journal of Agricultural and Food Chemistry

People who follow a vegan lifestyle – strict vegetarians who try to eat no meat or animal products of any kind – may increase their risk of developing blood clots and atherosclerosis or “hardening of the arteries,” which are conditions that can lead to heart attacks and stroke. That’s the conclusion of a review by Duo Li of dozens of articles published on the biochemistry of vegetarianism during the past 30 years. Vegan diets tend to be lacking several key nutrients – including iron, zinc, vitamin B12, and omega-3 fatty acids. While a balanced vegetarian diet can provide enough protein, this isn’t always the case when it comes to fat and fatty acids. As a result, vegans tend to have elevated blood levels of homocysteine and decreased levels of HDL, the “good” form of cholesterol. Both are risk factors for heart disease. Dietary supplements can supply these nutrients.

New gift from Mother Nature’s medicine chest may help prevent and treat bone diseases
ACS Medicinal Chemistry Letters

One of Mother Nature’s latest gifts to medical science is stirring excitement with the discovery that the substance Largazole – obtained from a coral-reef inhabiting cyanobacterium – appears to be an ideal blueprint for developing new drugs for serious fractures, osteoporosis, and other bone diseases, and it already has attracted scientific attention for its ability to kill cancer cells in laboratory experiments. Jiyong Hong, Seong Hwan Kim, Hendrik Luesch and colleagues report that in laboratory dishes and test animals Largazole has an unusual dual action on injured or diseased bones. It stimulates a process in the body called osteogenesis, which involves the growth of new bone and the repair of damaged bone. Largazole also blocks the opposite process in which the body naturally breaks down and resorbs bone. Both of those benefits, the scientists found, come from Largazole’s effects on proteins called histone deacetylases, which are a sort of a master control switch for protein production. Drugs that block histone deacetylases are currently used to treat cancer, and they may have other health benefits as well. The researchers also showed that Largazole, when mixed with bone components collagen and calcium phosphate, helped heal fractured bones in laboratory mice and rabbits.

Toward a fast, simple test for detecting cholera rampaging in 40 countries
Bioconjugate Chemistry

With cholera on the rampage in Haiti and almost 40 other countries, J. Manuel Perez and colleagues are reporting the development of a key advance that could provide a fast, simple test to detect the toxin that causes the disease. The authors note that cholera is an intestinal infection from food or water contaminated with the bacterium Vibrio cholerae, which produces a toxin that can cause severe diarrhea, potentially leading to rapid dehydration and death. Prompt treatment thus is essential, and yet existing tests to diagnose cholera are time-consuming, expensive, and require the use of complex equipment. The new method uses specially prepared nanoparticles of iron oxide, each barely 1/50,000th the width of a single human hair, coated with a type of sugar called dextran. To achieve this, the researchers looked for specific characteristics of the cholera toxin receptor (GM1) found on cells’ surface in the victim’s gut, and then they introduced these features to their nanoparticles. When the magnetic nanoparticles are added to water, blood, or other fluids to be tested, the cholera toxin binds to the nanoparticles in a way that can be easily detected by instruments.

High vitamin-D bread could help solve widespread insufficiency problem
Journal of Agricultural and Food Chemistry

With most people unable to get enough vitamin D from sunlight or foods, Connie Weaver and colleagues are suggesting that a new vitamin D-fortified food – bread made with high-vitamin D yeast – could fill that gap. Connie Weaver and colleagues cite studies suggesting that up to 7 in 10 people in the United States may not get enough vitamin D, which enables the body to absorb calcium. Vitamin D insufficiency has been linked to an increased risk of heart disease, cancer, allergy in children, and other conditions. Scientists thus have been looking for new ways to add vitamin D to the diet. Weaver’s group did experiments with laboratory rats, a stand-in for humans in such research, that ease doubts over whether bread baked with high vitamin D yeast could be a solution. The doubts originated because yeast produces one form of the vitamin, termed vitamin D2, which has been thought to be not as biologically active as the form produced by sun, vitamin D3. They showed bread made with vitamin D2-rich yeast, fed to the laboratory rats, had effects that seemed just as beneficial as vitamin D3.

Needle-in-a-haystack search identifies potential brain disease drug
Journal of Medicinal Chemistry

Scientists who examined more than 10,000 chemical compounds during the last year in search of potential new drugs for a group of untreatable, and invariably fatal, brain diseases, are reporting that one substance shows unusual promise. Adam Renslo and colleagues, who include Nobel Laureate Stanley B. Prusiner, explain that prion diseases include conditions like mad cow disease in animals and Creutzfeldt-Jakob Disease in humans, and result from deposits of abnormal prion protein in brain tissue. The scientists describe narrowing their search among the 10,000 candidate drugs to a few dozen of the most promising and then synthesizing new variations of the compounds, termed aminothiazoles. Tests on laboratory mice showed that the new compounds can reach the brain in high concentrations when taken orally and do not appear toxic. Tests on prion-infected mouse brain cells showed that the compounds reduced the amount of the abnormal prion protein. The compounds appear to be among the most promising potential treatments for prion diseases yet discovered, the report suggests.

An advance toward ultra-portable electronic devices
Journal of the American Chemical Society

Yuji Okawa and colleagues are reporting a key advance toward the long-awaited era of “single-molecule electronics,” when common electronic circuits in computers, smart phones, audio players, and other devices may shrink to the size of a grain of sand. The “key to single-molecule electronics is connecting functional molecules to each other using conductive nanowires. This involves two issues: how to create conductive nanowires at designated positions, and how to ensure chemical bonding between the nanowires and functional molecules.” Okawa, et al. demonstrated a method that uses the tip of a scanning tunneling microscope to jump-start the formation of a molecule chain. The chain or “wire” spontaneously chemically bonds with other molecular components in the circuit under construction, a process that Okawa and colleagues dub “chemical soldering.” The wiring method can be used to connect molecular switches, memory bits, and transistors.

New invisibility cloak hides objects from human view
Nano Letters

For the first time, scientists have devised an invisibility cloak material that hides objects from detection using light that is visible to humans. Xiang Zhang and colleagues note that invisibility cloaks, which route electromagnetic waves around an object to make it undetectable, “are still in their infancy.” Most cloaks are made of materials that can only hide things using microwave or infrared waves, which are just below the threshold of human vision. To remedy this, the researchers built a reflective “carpet cloak” out of layers of silicon oxide and silicon nitride etched in a special pattern. The carpet cloak works by concealing an object under the layers, and bending light waves away from the bump that the object makes, so that the cloak appears flat and smooth like a normal mirror. Although the study cloaked a microscopic object roughly the diameter of a red blood cell, the device demonstrates that it may be “capable of cloaking any object underneath a reflective carpet layer.”