|
InternetChemistry - Current Chemistry News of the Week
|
 |
The planet Jupiter keeps asteroids on stable orbits - and in a similar way, electrons can be stabilized in their orbit around the atomic nucleus; calculations carried out at the Vienna University of Technology have now been verified in an experiment.
Image: The Bohr model assumes that the electron moves around the nucleus, much like a planet around its star [Credit: Vienna University of Technology].
|
 |
Meteorite contains evidence of formation of sulfur molecules in the ejecta of a supernova explosion.
Image: The electron microscopic image shows a silicon carbide grain from the meteorite Murchison. The approximately one micrometer small grains originate from a supernova as an isotopic analysis has shown. Isotopes are forms of an element with different weights.
[Credit: Peter Hoppe, Max Planck Institute for Chemistry].
|
 |
Computer simulations revealing how methane and hydrogen pack into gas hydrates could enlighten alternative fuel production and carbon dioxide storage industries.
Image: A computer simulation of methane, also known as natural gas, escaping from a methane hydrate. Many of these methane hydrate subunits combine to form a chunk of ice that burns, and this simulation shows how methane can get out without collapsing the entire structure [Credit: Sotiris Xantheas, PNNL].
|
 |
Powerful drug's surprising, simple method could lead to better treatments [image credit: Martin Burke]. |
 |
Anti-malaria drug synthesised with the help of oxygen and light.
Image: Artemisinin combination treatments are the first-line drugs, but supplies are limited because artemisinin is obtained solely by extraction from Artemisia annua. A continuous-flow process that converts dihydroartemisinic acid into artemisinin is shown to be an inexpensive and scalable process that can ensure a steady, affordable supply of artemisinin [credit: Angewandte Chemie International Edition].
|
 |
Recycling platinum by electrochemical dissolution in an ionic liquid.
Image: Dissolving platinum: A noncorrosive, basic ionic liquid has been developed as a solvent system for the electrodissolution of platinum. The metal is dissolved at an ultrahigh rate, and the facile recovery of pure platinum and platinum alloys from the same solution is achieved without any additional treatment of the solution or exchange of the medium [Credit: Angewandte Chemie International Edition].
|
 |
The art of molecular carpet-weaving: Synthesis of well-ordered COF monolayers.
Image:
A scanning electron microscopy image with a superimposed molecular model. Two different straightforward synthetic approaches are presented to fabricate long-range-ordered monolayers of a covalent organic framework (COF) on an inert, catalytically inactive graphite surface.
[Credit: TU Munich]
|
 |
Livermore and Russian scientists propose new names for elements 114 and 116.
Image:
The place of Flerovium and Livermorium in the Periodic Table of the Elements.
|
| |
More News (open access): |
Mercury releases into the atmosphere from ancient to
modern times
|
|
|
The authors acknowledge funding from the
Department of Energy, the National Science
Foundation and from the Harvard University NIEHS
Center for Environmental Health.
[Credit: iStock]
|
In pursuit of riches and energy over the last
5,000 years, humans have released into the environment
385,000 tons of mercury, the source of numerous health
concerns, according to a new study that challenges the idea
that releases of the metal are on the decline. The report
appears in ACS’ journal Environmental Science & Technology.
David Streets and colleagues explain that humans put
mercury into the atmosphere by burning fossil fuels and
through mining and industrial processes. Mercury is present
in coal and the ores used to extract gold and silver. Much
information exists about recent releases of mercury, but
there is little information on releases in the past. To find
out how much impact people have had over the centuries, the
scientists reconstructed human additions of mercury to the
atmosphere using historical data and computer models.
Their research shows that mercury emissions peaked during
the North American gold and silver rushes in the late 1800s,
but after a decline in the middle of the 20th century, are
quickly rising again thanks mostly to a surge in coal use.
They report that Asia has overtaken Europe and America as
the largest contributor of mercury. Recent data suggest that
mercury concentrations in the atmosphere are declining, and
this is not consistent with their conclusion of increasing
emissions. Changing atmospheric conditions may be partly
responsible, but more work is also needed to understand the
fate of large amounts of mercury in discarded products like
batteries and thermometers. The researchers predict mercury
released from mining and fuel may take as many as 2,000
years to exit the environment and be reincorporated into
rocks and minerals in the Earth.
Environmental Science & Technology: "All-Time Releases of Mercury to the Atmosphere from Human Activities".
Environ. Sci. Technol., 2011, 45 (24), pp 10485–10491; DOI:
10.1021/es202765m.
Why coffee drinking reduces the risk of Type 2 diabetes
|
|
|
The authors acknowledge funding from the
National Natural Science Foundation of China, the
National Basic Research Program of China and the
Chinese Ministry of Education.
[Credit: iStock]
|
Why do heavy coffee drinkers have a lower risk of
developing Type 2 diabetes, a disease on the increase around
the world that can lead to serious health problems?
Scientists are offering a new solution to that long-standing
mystery in a report in ACS’ Journal of Agricultural & Food
Chemistry.
Ling Zheng, Kun Huang and colleagues explain that
previous studies show that coffee drinkers are at a lower
risk for developing Type 2 diabetes, which accounts for
90-95 percent of diabetes cases in the world. Those studies
show that people who drink four or more cups of coffee daily
have a 50 percent lower risk of Type 2 diabetes. And every
additional cup of coffee brings another decrease in risk of
almost 7 percent. Scientists have implicated the misfolding
of a substance called human islet amyloid polypeptide
(hIAPP) in causing Type 2 diabetes, and some are seeking
ways to block that process. Zheng and Huang decided to see
if coffee’s beneficial effects might be due to substances
that block hIAPP.
Indeed, they identified two categories of compounds in
coffee that significantly inhibited hIAPP. They suggest that
this effect explains why coffee drinkers show a lower risk
for developing diabetes. “A beneficial effect may thus be
expected for a regular coffee drinker,” the researchers
conclude.
Journal of Agricultural & Food Chemistry: “Coffee
Components Inhibit Amyloid Formation of Human Islet Amyloid
Polypeptide in Vitro: Possible Link between Coffee
Consumption and Diabetes Mellitus”. J. Agric. Food
Chem., 2011, 59 (24), pp 13147–13155; DOI:
10.1021/jf201702h.
| |
Chemistry |
|
 |
Graphene lights up with new possibilities: Rice researchers' two-step technique makes graphene suitable for organic chemistry.
Image: Making a superlattice with patterns of hydrogenated graphene is the first step in making the material suitable for organic chemistry. The process was developed in the Rice University lab of chemist James Tour [Credit: Tour Lab/Rice University].
|
 |
New material may boost efforts to convert gasoline infrastructure into one based on hydrogen.
Image: Stored hydrogen releases in the presence of iron chloride via a storage technology created in the University of Oregon lab of Shih-Yuan Liu.
[Courtesy of Shih-Yuan Liu]
|
 |
Researchers develop new process with porous molecular organic frameworks - relevant to the production of pharmaceuticals.
Image: Preferred (110) and (001) orientation of enantiopure [{Zn2((+)cam)2(dabco)}n] ((+)cam=(1R,3S)-(+)-camphoric acid, dabco=1,4-diazabicyclo(2.2.2)octane) thin films can be controlled by carboxylate and pyridyl groups on self-assembled monolayers (SAMs) [Credit: Angewandte Chemie International Edition].
|
 |
Scripps research team achieves critical step to opening elusive class of compounds to drug discovery.
Image: Elaboration of (+)-taxadienone to (+)-taxadiene by a three-step reduction-deoxygenation sequence [Credit: Nature Chemistry, DOI 10.1038/nchem.1196].
|
 |
Highly selective catalyst developed for ring-closing olefin metathesis. International team led by Boston College researchers uses new catalyst to synthesize two potent anti-cancer molecules.
Image: The total synthesis of nakadomarin A was realized through late-stage tungsten-catalysed ring-closing metathesis of the pentacyclic compound 13, and comparison with results delivered by Ruthenium catalysts.
[Credit: Nature DOI 10.1038/nature10563]
|
| |
Physics |
|
 |
Utah chemists: Water doesn't have to freeze until minus 55 Fahrenheit.
Image: The box here is full of liquid water, which is not shown (white). Supercooled liquid water starts to become “intermediate ice” (green) on the way to freezing into ice (red) well below the 32 degrees F that people normally consider water’s freezing point. University of Utah chemists calculated that supercold water finally must freeze at minus 55 F.
[Credit: University of Utah]
|
 |
Caltech engineers reveal how scandium trifluoride contracts with heat.
Image: The crystal structure of scandium trifluoride [Copyright APS].
|
 |
New equation developed by UCSB chemical engineers solves the mystery of forces between water-repelling and water-attracting molecules that are critical to industrial and medical applications.
Image: One example of how hydrophobic interactions are critical to biomedical applications can be found in how DNA base pairs on the two strands are drawn together to form a double helix. The basic structure of a DNA molecule is a hydrophilic backbone and a hydrophobic inner region of nitrogenous bases. These molecular hydrophobic forces repel the water between them which drives the bases towards each other [Credit: UCSB].
|
 |
A liquid does not have to be a disordered bunch of particles: A team of researchers has discovered intriguing structures formed by tiny particles floating in liquids. Under mechanical strain, particle clusters in liquids can spontaneously form strings and dramatically alter the properties of the liquid.
Image: Intriguing structures are formed by tiny particles floating in liquids.
[Credit: Vienna University of Technology]
|
| |
Biochemistry / Chemistry and Biology |
|
 |
On the path to tailored enzymes: Enzymatic synthesis of pyrrolysine, the mysterious 22nd amino acid.
Image: On the way to the production of pyrrolysine, an exotic amino acid occurring in only a few exotic organisms, the conversion of lysine to methylornithine is the decisive step. Scientists at the Technische Universitaet Muenchen succeeded in crystallizing the enzyme PylB which is responsible for this transformation and elucidated its structure. Top of the image: reactive center with an iron-sulfur cluster (red / yellow), the cofactor S-adenosylmethionine (SAM), and in the center of the image the product: 3-methyl-ornithine (3MO).
[Credit: Felix Quitterer, TU Muenchen]
|
 |
Robert Linhardt of Rensselaer Polytechnic Institute sequences bikunin - a proteoglycan.
Image: The portion on the left corresponds to the sugar part of the molecule, the sequence of which was determined in the current study. The portion on the right corresponds to the protein part of bikunin.
[Credit: Rensselaer Polytechnic Institute]
|
 |
Colorful leaves: New chlorophyll decomposition product found in Norway maple.
Image: A colorless chlorophyll catabolite was found in senescent leaves of Norway maple, a widespread deciduous tree. This compound is a dioxobilane, a “linear” tetrapyrrole, in which one meso carbon of the macrocycle of the hypothetical chlorophyll precursor has been lost. The configuration of this catabolite suggests a path of chlorophyll breakdown in Norway maple that diverges from that found in senescent leaves of other higher plants.
[Credit: Angewandte Chemie International Edition]
|
| |
Chemistry and Medicine |
|
|
A natural compound isolated from a wild, poisonous mushroom growing in a Southwest China forest appears to help a cancer killing drug fulfill its promise, researchers report.
|
 |
Coffee in capsules contains more furan than the rest.
Image:
Coffee in capsules contains more furan than the rest,
although the levels are still within safe health limits.
[Credit: SINC]
|
 |
Double strike to fight cancer - combined diagnosis and treatment of tumors: photothermically activated ultrasound contrast agent.
Image: The combination of electrostatic deposition of gold nanoparticles onto microcapsules and a surface seeding method results in the formation of gold nanoshells (see picture). This nano/micro composite is able to operate as a theranostic agent for both contrast-enhanced ultrasonic imaging (diagnostic) and photohyperthermia (therapeutic), and thus holds a great potential for photothermal therapy in cancer treatment.
[Credit: Angewandte Chemie International Edition].
|
| |
Chemistry and Materials |
|
|
Dimensional Reduction: New materials hold promise for better detection of nuclear weapons.
|
 |
Researchers design a self-assembling material that can house other molecules.
Image:
This is a scanning electron microscope image of a new material that self-assembles into a polyhedron using the attractive interactions associated with hydrogen bonds.
The shapes then further organize into a crystal lattice that resembles a porous structure called zeolite, an absorbent material with many industrial uses.
[Credit: Michael D. Ward, New York University].
|
 |
Upgrading the vanadium redox battery: New electrolyte mix increases energy storage by 70 percent.
Image:
This artist's rendering of an upgraded vanadium redox battery shows how using both hydrochloric and sulfuric acids in the electrolyte significantly improves the battery's performance and could also improve the electric grid’s reliability and help connect more wind turbines and solar panels to the grid.
[Credit: Pacific Northwest National Laboratory]
|
| |
Chemistry and Nanotechnology |
|
 |
World's smallest electric motor made from a single molecule. Image: Chemists at Tufts University have developed the world's first single molecule electric motor, which may potentially create a new class of devices that could be used in applications ranging from medicine to engineering.
[Credit: Heather L. Tierney et al.]
|
 |
Berkeley Lab researchers use nanoantenna to enhance plasmonic sensing.
Image: This is a scanning electron microscopy image showing a palladium nanoparticle with a gold antenna to enhance plasmonic sensing.
[Image courtesy of Alivisatos group]
|
 |
An international research team has discovered a new method to
produce belts of graphene called nanoribbons.
Image: Reaction of single-walled carbon nanotubes (SWNTs) with hydrogen gas was studied in a temperature interval of 400–550 °C and at hydrogen pressure of 50 bar [Credit: The Swedish Research Council].
|
| |
Chemistry and Environment |
|
 |
How the N2O greenhouse gas is decomposed.
Image: The N2O-reductase enzyme possesses four reactive centers for the decomposition of nitrous oxide into elemental nitrogen.
[Source: BIOSS/ University of Freiburg]
|
|
New evidence for natural synthesis of silver nanoparticles.
|
 |
Worldwide sulfur emissions rose between 2000-2005, after decade of decline. Shipping, China top emissions growth in new analysis of 150 years of emissions.
Image: Manmade sulfur dioxide emissions by country show a decline by the historically large emitters - Europe and the US - but increases in growing economies up to 2005.
[Credit: Smith et al., Atmos Chem Phys 2011].
|
| |
Geochemistry |
|
 |
Astrobiologists discover 'sweet spots' for the formation of complex organic molecules in the galaxy. Image: Methanol formation is the major chemical pathway to complex organic molecules in interstellar space.
If scientists can identify regions where conditions are right
for rich methanol production, they will be better able to
understand where and how the complex organic molecules needed to
create life are formed.
[Photo courtesy of NASA]
|
 |
Nitrogen-containing soil is a source of hydroxyl radicals that remove pollutants from the atmosphere.
Image:
What is the source of nitrous acid in the atmosphere?
Mainz scientists study the exchange of gases between soil samples and the air in this reaction chamber
[Credit: Su, Max Planck Institute for Chemistry].
|
|
New research shows evidence of early oxygen on our planet.
|
|
|
