Archive for April, 2013

Speeding up your NMR data acquisition

There has been an increase in the popularity and practical application of hyperpolarization NMR/MRI.  One way to achieve high levels of nuclear spin polarization is based on the notion that as the temperature is reduced (characterized by the spin-lattice relaxation time, T1), the equilibrium nuclear polarization will increase, according to the Boltzmann distribution. The main problem with this approach is the length of time it may take to approach thermal equilibrium at low temperatures, since nuclear relaxation times can become very long.

Now, scientists in the UK show that DTPA(diethylene triamine pentacetic acid)-chelated lanthanides can be used as spin-lattice relaxation T1-shortening agents of nuclear spins, to expedite NMR data. Differential effects are seen with different lanthanides, with holmium and dysprosium causing the most relaxation, while gadolinium is ineffective at temperatures of 20 K and below.

Reducing the T1 values of the relevant nuclei increases the rate at which data can be acquired, and this new method is hoped to have applications in routine chemical analysis, as well as in selected tissue metabolism studies that require only coarse spatial localization.

Read the full details of this exciting development:

Achievement of high nuclear spin polarization using lanthanides as low-temperature NMR relaxation agents
David T. Peat, Anthony J. Horsewill, Walter Kockenberger, Angel J. Perez Linde, David G. Gadian and John Robert Owers-Bradley
DOI: 10.1039/C3CP00103B

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Astrochemistry of Dust, Ice and Gas: call for papers

PCCP themed issue: call for papers

PCCP themed issue: Astrochemistry of Dust, Ice and Gas
Guest Editor: Wendy Brown (University of Sussex)

PCCP is delighted to announce a high-profile themed issue ‘Astrochemistry of Dust, Ice and Gas’. It is our pleasure to invite you to submit an original research article for this themed issue.

The themed issue will be published in Physical Chemistry Chemical Physics (PCCP) in 2014. It will receive great exposure, and get significant promotion, including promotion at Faraday Discussion 168, which will also cover the astrochemistry of dust, ice and gas, in April 2014, Leiden, The Netherlands.

PCCP is a high-impact, community spanning, international journal publishing work of the highest quality in the broad fields of physical chemistry, chemical physics and biophysical chemistry.

Deadline for Submissions: 27th September 2013

  • Manuscripts can be submitted in any reasonable format using our online submissions service
  • Submissions should be high quality manuscripts of original, unpublished research and must contain new physical insight
  • Communications and full papers can be submitted for consideration, which will be subject to rigorous peer review
  • Please indicate upon submission that your manuscript is intended for this themed issue

Please contact the PCCP Editorial Office to let us know you plan to contribute an article.

The young interdisciplinary science of Astrochemistry, lying at the interface of Astronomy, Astrophysics, Physics and Chemistry, has become a critical science in not only elucidating the products, mechanisms and rates of the chemistry that dominates the Universe but also for determining the physical properties of the molecular gas clouds that form stars and planets. Therefore, it is timely to publish a themed collection in PCCP on this emerging and exciting area of research. It is envisaged that the themed collection will bring together work from leading computational and experimental scientists, astronomers, chemists and biologists that addresses the cyclic role of dust in the chemical evolution of the Universe.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Surprising insights on metallic clusters

Table of contents imageBetween bulk metals and their individual atoms lies the murky world of metallic clusters. These often have unique properties, and understanding them is as challenging as it is interesting. Many properties are a direct function of cluster size, and provide important insights into the progression from individual atoms to bulk solids. It is therefore important to ascertain the exact size at which a particle ceases to be classified as a cluster and becomes a bulk solid. This moment can either be measured experimentally or calculated using a theoretical model.

Aluminium bridges the gap between monovalent and multivalent clusters, as it is monovalent as a single atom, but becomes trivalent with hybridized orbitals at larger cluster sizes. The exact cluster size at which this hybridisation occurs is still the matter of intense debate, with little coherence amongst the results of a large number of studies, both experimental and theoretical.

Melko and Castleman attempt to resolve this problem by conducting both a theoretical study and an experimental study using the angular distribution information obtained from photoelectron imaging. They then developed a calibration curve that allowed them to quantitatively compare their results, which were rather surprising. They suggest that the orbital hybridisation that indicates bulk behaviour begins to appear at cluster sizes as small as Al3, which is considerably smaller than previously thought. The extent of the hybridisation then appears to oscillate as successive atoms are added to the cluster up to at least Al6, suggesting the existence of a transition period between the monovalent and trivalent states, rather than a discrete threshold.

by Victoria Wilton

Read the full details of this fascinating PCCP article:

Photoelectron imaging of small aluminum clusters: quantifying s–p hybridization
Joshua J. Melko and A. W. Castleman
DOI: 10.1039/C3CP43158D

If you enjoyed this paper you may also be interested in the Nanoscale themed issue on Metallic clusters – please do take a look.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Insights into co-doping of TiO2 for photocatalytic applications

Jinlong Gong and co-workers provide novel insights into TiO2 co-doping for photocatalytic applications in their recent PCCP paper.

Understanding Electronic and Optical Properties of Anatase TiO2 Photocatalysts co-doped with Nitrogen and Transition Metals

The group investigated the general trend of electronic properties of anatase TiO2 photocatalysts co-doped with transition metals and nitrogen using first-principles density functional theory. They found that the absorption edges of TiO2 are shifted to the visible-light region upon introduction of dopants, due to the reduced conduction band minimum and the formation of impurity energy levels in the band gap. They propose that co-doping systems such as (V, N), (Cr, N), and (Mn, N), which have impurity energy levels with significant bandwidths, are the most promising candidates for photovoltaic applications in the visible light range.

Read this HOT article today:

Understanding Electronic and Optical Properties of Anatase TiO2 Photocatalysts co-doped with Nitrogen and Transition Metals
Qingsen Meng, Tuo Wang, Enzuo Liu, Xinbin Ma, Qingfeng Ge and Jinlong Gong
DOI: 10.1039/C3CP51476E

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

PCCP themed collection: Plasmonics and spectroscopy – out now!

We are delighted to announce that the PCCP themed collection on Plasmonics and spectroscopy now been published online – take a look today!

The themed collection was Guest Edited by Pablo G. Etchegoin – read his Editorial for this issue.

The outside front cover features a perspective article on Nanogap structures: combining enhanced Raman spectroscopy and electronic transport by Douglas Natelson, Yajing Li and Joseph B. Herzog.

Plasmonics and spectroscopy themed collection features a broad range of Papers and Communications and includes the following Perspective articles:

Single-molecule surface-enhanced Raman spectroscopy: a perspective on the current status
Hae Mi Lee, Seung Min Jin, Hyung Min Kim and Yung Doug Suh
DOI: 10.1039/C3CP44463E

Towards low-cost flexible substrates for nanoplasmonic sensing
Lakshminarayana Polavarapu and Luis M. Liz-Marzán
DOI: 10.1039/C2CP43642F

Persistent misconceptions regarding SERS
Martin Moskovits
DOI: 10.1039/C2CP44030J

Recent developments and future directions in SERS for bioanalysis
Mhairi M. Harper, Kristy S. McKeating and Karen Faulds
DOI: 10.1039/C2CP43859C

Medical applications of surface-enhanced Raman scattering
Wei Xie and Sebastian Schlücker
DOI: 10.1039/C3CP43858A

Super-resolution imaging of interactions between molecules and plasmonic nanostructures
Katherine A. Willets
DOI: 10.1039/C3CP43882A

Plasmon enhanced spectroscopy
Ricardo F. Aroca
DOI: 10.1039/C3CP44103B

Take a look at the issue today!

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Hydrogen storage by physisorption on dodecahydro-closo-dodecaboranes

Hydrogen storage by physisorption on dodecahydro-closo-dodecaboranes

Guntram Rauhut, Emil Roduner and co-workers from the University of Stuttgart have studied the hydrogen storage potential dodecahydro-closo-dodecaborane units using both theoretical and experimental approaches. They address important issues concerning the thermodynamics of optimised hydrogen storage.

Read this HOT article today:

Hydrogen storage by physisorption on dodecahydro-closo-dodecaboranes
Lucia Dienberg, Julia Haug, Guntram Rauhut and Emil Roduner
DOI: 10.1039/C3CP43848A

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Electron transfer, enzyme electrodes and biofuel cells

Paul Kavanagh and Dónal Leech review methods that aid the development of glucose oxidising enzyme electrodes and their application as continuous-use anodes in biofuel cells in their recent PCCP Perspective.  They focus on the rational design of mediators, based on osmium redox complexes, but also give an overview of the performance of enzyme electrodes.

Read this excellent Perspective article today:

Mediated electron transfer in glucose oxidising enzyme electrodes for application to biofuel cells: recent progress and perspectives
Paul Kavanagh and Dónal Leech
DOI: 10.1039/C3CP44617D

Mediated electron transfer in glucose oxidising enzyme electrodes for application to biofuel cells: recent progress and perspectives

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

PCCP article in Chemistry World: Surface freezing in nanodroplets

Experiments carried out by scientists in the US have provided new evidence in the controversial issue of surface freezing in alkane nanodroplets.

Experimental evidence for surface freezing in supercooled n-alkane nanodroplets

For small droplets, or systems with free surfaces, such as those in atmospheric aerosols, the freezing mechanism of hydrocarbons is a highly debated topic. Until now, experimental techniques have not been able to distinguish between surface and volume freezing.

Barbara Wyslouzil and colleagues at the Ohio State University, Columbus, are interested in understanding phase transitions and organization in nanodroplets. ‘Since surface-to-volume ratio increases as objects get smaller, nanodroplets present an obvious advantage for the study of surface effects,’ says Wyslouzil. Nanodroplets of n-octane and n-nonane were formed and rapidly cooled in a continuous flow supersonic Laval nozzle. As the condensable carrier gas mixture flows through the nozzle, the flow accelerates, effectively cooling as the pressure and temperature drop. This first condenses the vapour to liquid droplets, then freezes them.

Read the full article in Chemistry World here…

Read this article in PCCP:

Experimental evidence for surface freezing in supercooled n-alkane nanodroplets
Viraj P. Modak, Harshad Pathak, Mitchell Thayer, Sherwin J. Singer and Barbara E. Wyslouzil
DOI: 10.1039/C3CP44490B

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Studying the effects of membrane interaction and aggregation of amyloid β-peptide

Kenji Sasahara and co-authors from Japan reveal important insights into the effect of amyloid β-peptide aggregation on the dynamic properties and organization of lipid membranes in their recent PCCP paper.  Their article will be included in the upcoming PCCP themed issue on biophysical studies of protein misfolding and amyloid diseases.

Effects of membrane interaction and aggregation of amyloid β-peptide on lipid mobility and membrane domain structure

Solving the very complex biological problem of how soluble, nontoxic amyloid β-peptide become toxic amyloid fibrils rich in β-sheet structures is important in understanding Alzheimer’s disease. Previous studies have shown that ganglioside GM1 in lipid rafts are key in converting non-toxic to toxic ab species. However, there is still a vast amount to understand about the interaction of lipids and amyloid β-peptides.

Read this HOT article today:

Effects of membrane interaction and aggregation of amyloid β-peptide on lipid mobility and membrane domain structure
Kenji Sasahara, Kenichi Morigaki and Kyoko Shinya
DOI: 10.1039/C3CP44517H

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Molecular sentinel-on-chip for SERS-based biosensing

In their recent PCCP paper, Tuan Vo-Dinh, Anuj Dhawan et al. describe a unique ‘‘molecular sentinel-on-chip’’ technology for SERS-based DNA detection. They fabricated wafer-thin, triangular-shaped nanowire  arrays, and used these to detect a DNA sequence of the Ki-67 gene, a critical breast cancer biomarker.

Read this HOT article today:

Molecular sentinel-on-chip for SERS-based biosensing
Hsin-Neng Wang, Anuj Dhawan, Yan Du, Dale Batchelor, Donovan N. Leonard, Veena Misra and Tuan Vo-Dinh
DOI: 10.1039/C3CP00076A

Molecular sentinel-on-chip for SERS-based biosensing

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)