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InternetChemistry - Current Chemistry News of the Week
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UCLA chemists solved a molecular mystery, and report the discovery in the journal Nature Communications.
Image - Achiral triangles form chiral super-structures:
Colored patches represent parallelogram outlines around pairs of triangles that have formed chiral super-structures.
Parallelograms having different 'handedness' and orientations are color-coded and superimposed over each other.
[Credit: Thomas G. Mason and Kun Zhao]
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Vanderbilt researchers have boosted the efficiency of a novel source of white light called quantum dots more than tenfold, making them of potential interest for commercial applications.
Image: Enhanced and original white light quantum dots: Pictured is a vial holding original white-light quantum dots on the left and a vial holding the enhanced quantum dots on the right [Credit: Rosenthal Lab].
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Chemical engineers at UMass Amherst find high-yield method of making p-xylene from biomass.
Image: Reasearchers investigated a renewable route to p-xylene from biomass-derived dimethylfuran and ethylene with zeolite catalysts. Cycloaddition of ethylene and 2,5-dimethylfuran and subsequent dehydration to p-xylene has been achieved with 75% selectivity using a H–Y zeolite and an aliphatic solvent at 300 °C.
[Credit: University of Massachusetts, Amherst]
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Comparing apples and oranges: New sensor can accurately measure fruits' ripeness, helping prevent loss of produce from spoilage.
Image: The selective detection of ethylene gas using a carbon nanotube-based devices is described in the journal Angewandte Chemie.
[Credit: MIT]
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Scientists at the University of Cambridge and the Babraham Institute have demonstrated a new technique that will transform epigenetics research: The quantitative
sequencing of 5-methylcytosine and 5-hydroxymethylcytosine at single-base resolution.
Image: The centre of the diagram shows levels of 5mC and 5hmC chemical modifications along a chromosome (section of DNA). The cycle illustrates that after addition to DNA, 5mC (blue) can be converted to 5hmC (red) and then subsequently removed [Credit: Miguel Branco].
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Protein design is technique that is increasingly valuable to a variety of fields, from biochemistry to therapeutics to materials engineering. University of Pennsylvania chemists have taken this kind of design a step further; using computational methods, they have created the first custom-designed protein crystal. Image: Illustration of the researchers' target protein crystal [Credit: Christopher MacDermaid, University of Pennsylvania].
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A small molecule moves independently along a track. Image: A molecule is able to walk back and forth upon a five-foothold pentaethylenimine track without external intervention.
[Credit: Angewandte Chemie International Edition].
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The first seconds in a building’s life: X-ray diffraction studies of cement hydration on the millisecond scale.
Image: Highly dynamic hydration processes that occur during the first seconds of cement hydration were studied by time-resolved synchrotron X-ray diffraction.
Polycarboxylate ether additives were found to influence the formation of the initial crystalline hydration products on a molecular level.
[Credit: Angewandte Chemie International Edition]
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Sticky stuff: Jacobs researchers reveal the sweet secret of caramel.
Image: At least 4000 chemical components can be found in caramel.
[Cedit: iStockphoto]
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More News (open access): |
That caffeine in your drink - is it really 'natural?'
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That caffeine in your drink - is it
really 'natural?'
[Credit: iStock]
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That caffeine in your tea, energy drink or other
beverage - is it really natural? Scientists are reporting
successful use for the first time of a simpler and faster
method for answering that question. Their report appears in
the American Chemical Society (ACS) journal Analytical
Chemistry.
Maik A. Jochmann, Ph.D., and colleagues point to the
growing consumer preference for foods and beverages that
contain only natural ingredients. Coffee, tea, colas, energy
drinks and other caffeine-containing drinks are the most
popular beverages in the world. Food regulatory agencies
require that caffeine be listed on package labels, but do
not require an indication of whether the caffeine is from
natural or synthetic sources. The scientists set out to
develop a faster, simpler method for categorizing caffeine’s
origins.
In the study, they describe use of a technique called
stable-isotope analysis to differentiate between natural and
synthetic caffeine. The test makes use of differences in the
kinds of carbon isotopes – slight variations of the same
element – found in caffeine made by plants and caffeine made
in labs with petroleum-derived molecular building blocks.
Their analysis, which takes as little as 15 minutes, found
four products that contained synthetic caffeine, despite a
“natural” label.
The authors acknowledge funding from the German Federal
Ministry of Economics and Technology and the German Research
Foundation.
Analytical Chemistry: "Caffeine
in Your Drink: Natural or Synthetic?". Anal. Chem.,
2012, 84 (6), pp 2805–2810; DOI: 10.1021/ac203197d.
Pig stomach mucins are effective as anti-viral agents
for consumer products
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Mucin Biopolymers as Broad-Spectrum
Antiviral Agents
[Credit: iStock]
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Scientists are reporting that the mucus lining
the stomachs of pigs could be a long-sought, abundant source
of “mucins” being considered for use as broad-spectrum
anti-viral agents to supplement baby formula and for use in
personal hygiene and other consumer products to protect
against a range of viral infections. Their study appears in
ACS’ journal Biomacromolecules.
In the report, Katharina Ribbeck and colleagues point out
that mucus, which coats the inside of the nose, mouth and
vagina, is the immune system’s first line of defense. The
slimy secretion traps disease-causing microbes, ranging from
influenza virus to HIV (which causes AIDS) before they can
cause infection. That has led to consideration of mucin, the
main component of mucus, for use as an anti-viral agent in a
variety of products. However, existing sources of mucins,
such as breast milk, cannot provide industrial-sized
quantities. Large amounts of mucus exist in the lining of
pigs’ stomachs, and the authors set out to determine if pig
mucus - already used as a component of artificial saliva to
treat patients with “dry mouth,” or xerostomia - has the
same anti-viral activity.
They found that pig mucus is effective at blocking a
range of viruses, from strains of influenza to the human
papilloma virus, which is associated with cervical and oral
cancer. They report that pig mucins could be added to
toothpastes, mouthwashes, wound ointments and genital
lubricants to protect against viral infections. “We envision
porcine gastric mucins to be promising antiviral components
for future biomedical applications,” the report says.
The authors acknowledge the National Institutes of Health
and the German Academic Exchange Service (DAAD).
Biomacromolecules: "Mucin
Biopolymers as Broad-Spectrum Antiviral Agents". 2012,
DOI 10.1021/bm3001292.
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Chemistry |
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Biocompatible, waterproof, self-healing, and reversible: A new adhesive for medical applications?
Image: Bioinspired underwater chemical bonding with the possibility of phototriggered debonding is reported. A four-arm star-poly(ethyleneglycol) end-functionalized by nitrodopamine was synthesized.
[Credit: Angewandte Chemie International Edition]
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Using infrared spectroscopy, scientists detect that oxygen defects act as active centers [Graphics: Dr. M. Xu, RUB]. |
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Glowing white: researchers develop uncharged organic substances that are luminescent liquids at room temperature and require no solvent.
Image: Isolation of a π-core by covalently attached flexible hydrocarbon chains has been employed to synthesize blue-emitting oligo(p-phenylenevinylene) (OPV) liquids with tunable viscosity and optical properties [Credit: Angewandte Chemie].
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Touch of gold improves nanoparticle fuel-cell reactions. [Image credit: Sun Lab/Brown University]
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Physics |
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2 for 1: Simultaneous size and electrochemical measurement of nanomaterials.
Image: Schematic of NIST's 'eSANS' cell. A highly porous, sponge-like carbon electrode maximizes surface area for electrochemical reactions while structural details like particle size and configuration are measured using neutron scattering [Credit: Prabhu/NIST].
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Image or Mirror Image? - Chiral recognition by femtosecond laser.
Image: A circular dichroism effect in the +/- 10 % regime on randomly oriented chiral molecules in the gas phase is demonstrated. The signal is derived from images of photoelectron angular distributions (see picture) produced by resonance-enhanced multiphoton ionization and allows the enantiomers to be distinguished. To date, this effect could only be generated with a synchrotron source. The new tabletop laser-based approach will make this approach for more accessible
[Credit: Angewandte Chemie]
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Oxygen molecule survives to enormously high pressures - RUB researcher calculates stability thresholds and structures of solid oxygen.
Image:
Structures of solid oxygen under high pressure - at 1.9 TPa, oxygen polymerizes and assumes a square spiral-like structure, which is semi-conducting ...
[Figure: Jian Sun]
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Biochemistry / Chemistry and Biology |
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Scientists of the University of Innsbruck, Austria, tested a new chemical modification of RNA molecules successfully for the first time. The results of the close cooperation of two research groups of the Centre for Molecular Biosciences (CMBI) have been published in the journal ACS Chemical Biology.
Image: A fluorescent dye lightens up the modified RNA in the cell.
[Credit: University of Innsbruck]
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Max Planck scientists identify one of the key players of the folding process: the molecular chaperone DnaK.
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Deadly chinese mushrooms: Amino acids revealed as cause of deaths in Yunnan province.
Image: Two unusual and toxic amino acids, 2R-amino-4S-hydroxy-5-hexynoic acid and 2R-amino-5-hexynoic acid have been isolated from the fruiting bodies of the mushroom Trogia venenata [Credit: Angewandte Chemie].
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Chemistry and Medicine |
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Keeping track to selenium metabolism: Spanish and Danish researchers have developed a method for the in vivo study of the unknown metabolism of selenium, an essential element for living beings. The technique can help clarify whether or not it possesses the anti-tumour properties that have been attributed to it and yet have not been verified through clinical trials.
Image: The technique allows for infinitesimal amounts of selenium to be quantified in their different chemical forms.
[Credit: J. Giner et al.].
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Responding to the radiation threat - Berkeley Lab researchers developing promising treatment for safely decontaminating humans exposed to radioactive actinides.
Image: This octadentate HOPO is a sequestering agent that can encapsulate actinides, such as this plutonium atom (gold), into tightly bound cage-like complexes for excretion out of the body.
[Image by Zosia Rostomian, Berkeley Lab]
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Powerful drug's surprising, simple method could lead to better treatments [image credit: Martin Burke]. |
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Chemistry and Materials |
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Dimensional Reduction: New materials hold promise for better detection of nuclear weapons.
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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].
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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]
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Chemistry and Nanotechnology |
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A bronze matryoshka doll - The metal in the metal in the metal: New way to highly efficient catalysts and nanotubes with unusual symmetry.
Image: Just like in the Russian wooden toy, a hull of 12 copper atoms encases a single tin atom.
This hull is, in turn, enveloped by 20 further tin atoms. With their large surfaces these structures can serve as highly efficient catalysts.
[Credit: TUM]
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Bright lights of purity: Berkeley Lab researchers discover why pure quantum dots and nanorods shine brighter.
Image: This shows the luminescence of CdSe/CuS nanocrystals prepared by cation-exchange. On the left are crystals prior to purification, on the right are the same nanocrystals after impurities have been removed.
[Credit: Berkeley Lab]
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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]
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Chemistry and Environment |
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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]
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New evidence for natural synthesis of silver nanoparticles.
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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].
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Geochemistry |
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An 11,000 year-old deep-sea sponge provides a record of past environmental changes in the sea.
Image: Microscopic image of a glass sponge. The image shows a one millimeter cross section of the skeleton of Monorhaphis chuni. The lamellae grew inside outwards during the 11,000 years.
[Credit: Werner E. G. Müller, University Medical Center
Mainz]
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Meteorites reveal another way to make life's components.
Image:
A meteorite is analyzed in the study at its collection site in Antarctica.
[Credit: Antarctic Search for Meteorites program, Case
Western Reserve University]
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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].
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