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result(s) for
"Layfield, Richard A."
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Lanthanides and actinides in molecular magnetism
by
Layfield, Richard A
,
Murugesu, Muralee
in
Actinide elements
,
Actinium compounds
,
Actinium compounds -- Mangnetic properties
2015
The first reference on this rapidly growing topic provides an essential up-to-date guide to current and emerging trends.A group of international experts has been carefully selected by the editors to cover all the central aspects, with a focus on molecular species while also including industrial applications.
Magnetic hysteresis up to 80 kelvin in a dysprosium metallocene single-molecule magnet
by
Mansikkamäki, Akseli
,
Day, Benjamin M.
,
Tong, Ming-Liang
in
Cations
,
Climate
,
Cooling effects
2018
Single-molecule magnets could prove useful in miniaturizing a wide variety of devices. However, their application has been severely hindered by the need to cool them to extremely low temperature using liquid helium. Guo
et al.
now report a dysprosium compound that manifests magnetic hysteresis at temperatures up to 80 kelvin. The principles applied to tuning the ligands in this complex could point the way toward future architectures with even higher temperature performance.
Science
, this issue p.
1400
Ligand tuning raises the upper temperature for hysteresis in a single-molecule magnet just above nitrogen’s boiling point.
Single-molecule magnets (SMMs) containing only one metal center may represent the lower size limit for molecule-based magnetic information storage materials. Their current drawback is that all SMMs require liquid-helium cooling to show magnetic memory effects. We now report a chemical strategy to access the dysprosium metallocene cation [(Cp
i
Pr5
)Dy(Cp*)]
+
(Cp
i
Pr5
, penta-iso-propylcyclopentadienyl; Cp
*,
pentamethylcyclopentadienyl), which displays magnetic hysteresis above liquid-nitrogen temperatures. An effective energy barrier to reversal of the magnetization of
U
eff
= 1541 wave number is also measured. The magnetic blocking temperature of
T
B
= 80 kelvin for this cation overcomes an essential barrier toward the development of nanomagnet devices that function at practical temperatures.
Journal Article
Influencing the properties of dysprosium single-molecule magnets with phosphorus donor ligands
2015
Single-molecule magnets are a type of coordination compound that can retain magnetic information at low temperatures. Single-molecule magnets based on lanthanides have accounted for many important advances, including systems with very large energy barriers to reversal of the magnetization, and a di-terbium complex that displays magnetic hysteresis up to 14 K and shows strong coercivity. Ligand design is crucial for the development of new single-molecule magnets: organometallic chemistry presents possibilities for using unconventional ligands, particularly those with soft donor groups. Here we report dysprosium single-molecule magnets with neutral and anionic phosphorus donor ligands, and show that their properties change dramatically when varying the ligand from phosphine to phosphide to phosphinidene. A phosphide-ligated, trimetallic dysprosium single-molecule magnet relaxes via the second-excited Kramers' doublet, and, when doped into a diamagnetic matrix at the single-ion level, produces a large energy barrier of 256 cm
−1
and magnetic hysteresis up to 4.4 K.
Ligand design contributes to dictating the magnetic properties of lanthanide-based single-molecule magnets. Here, the authors report a series of phosphorus-ligated dysprosium complexes, and show that the dynamic magnetic properties change as the ligand is varied from phosphine to phosphide to phosphinidene.
Journal Article
Molecular Testing Strategies for Pulmonary Adenocarcinoma: An Optimal Approach With Cost Analysis
by
Furtado, Larissa V.
,
Schmidt, Robert L.
,
White, Sandra K.
in
Adenocarcinoma
,
Adenocarcinoma of Lung - genetics
,
c-Met protein
2019
Molecular analysis of lung adenocarcinoma for therapeutically important genes is standard of practice, with multiple professional organizations recommending testing of all adenocarcinomas for mutations in
,
, and
. Some organizations recommend analyzing these genes in association with a panel. Few data exist as to optimal testing method or optimal sequence of testing from a cost perspective.
To determine which order of gene testing was least costly and whether sequential, small panel, or next-generation sequencing (NGS) was cheapest.
Recent recommendations propose a set of essential molecular tests (
,
, and
) and an optional set of molecular tests that may be useful for selection of clinical trials. We compared the costs of different testing sequencing strategies for both the 3 essential genes and for 5 optimal genes. Testing costs were determined by a survey of prices from large laboratories. The strategy most frequently rated as the lowest cost strategy was designated the optimal testing strategy.
Sequential testing of the essential genes in the order
-
-
was optimal from a cost perspective. The expected cost of sequential testing was $2227 (95% CI, $1733-$2794). The cost of NGS was $2500. The expected cost per positive result was $11,362 using this strategy.
Molecular testing of lung adenocarcinomas for the set of 3 essential genes and 5 optional genes can be performed by a variety of methods and in a variety of sequences. From a cost perspective, sequential testing in the order
,
, then
is optimal. NGS would be competitive if the price was less than $2200. NGS is optimal if testing for the 3 essential genes will be followed by testing for the 5 optional genes. NGS testing is optimal if the clinician plans to test both essential and optional genes.
Journal Article
A Biphasic Pleural Tumor With Features of Desmoplastic Small Round Cell Tumor and Malignant Mesothelioma
2015
FISH for rearrangements of the 22q12 EWSR1 by breakapart probes was negative, but 94% of tumor nuclei had only 1 intact copy of the EWSR1 gene. The present case has morphologic, immunohistochemical and molecular features of both mesothelioma and DSRCT and further strengthens the hypothesis of a common cell of origin for both mesothelioma and DSRCTs. © American Society for Clinical Pathology Am J Clin Pathol 2015;144:
Journal Article
Evaluation of a novel antibody to define histone 3.3 G34R mutant brain tumours
by
Bountali, Aikaterini
,
Storer, Lisa
,
Layfield, Robert
in
Animals
,
Antibodies
,
Antibodies - isolation & purification
2017
Missense somatic mutations affecting histone H3.1 and H3.3 proteins are now accepted as the hallmark of paediatric diffuse intrinsic pontine gliomas (DIPG), non-brain stem paediatric high grade gliomas (pHGG) as well as a subset of adult glioblastoma multiforme (GBM). Different mutations give rise to one of three amino acid substitutions at two critical positions within the histone tails, K27M, G34R/V. Several studies have highlighted gene expression and epigenetic changes associated with histone H3 mutations; however their precise roles in tumourigenesis remain incompletely understood. Determining how such amino acid substitutions in a protein affect its properties can be challenging because of difficulties in detecting and tracking mutant proteins within cells and tissues. Here we describe a strategy for the generation of antibodies to discriminate G34R and G34V mutant histone H3 proteins from their wild-type counterparts. Antibodies were validated by western blotting and immunocytochemistry, using recombinant H3.3 proteins and paediatric GBM cell lines. The H3-G34R antibody demonstrated a high degree of selectivity towards its target sequence. Accordingly, immunostaining on a cohort of 22 formalin-fixed paraffin embedded tumours with a previously known H3.3 G34R mutation status, detected successfully the corresponding mutant protein in 11/11 G34R cases. Since there was a high concordance between genotype and immunohistochemical analysis of G34R mutant tumour samples, we analysed a series of tissue microarrays (TMAs) to assess the specificity of the antibody in a range of paediatric brain tumours, and noted immunoreactivity in 2/634 cases. Importantly, we describe the generation and validation of highly specific antibodies for G34 mutations. Overall our work adds to an extremely valuable portfolio of antibodies, not only for histopathologic detection of tumour-associated mutant histone sequences, but also facilitating the study of spatial/anatomical aspects of tumour formation and the identification of downstream targets and pathways in malignant glioma progression.
Journal Article