88 research outputs found
Review on Experimental and Theoretical Investigations of Ultra-Short Pulsed Laser Ablation of Metals with Burst Pulses
Laser processing with ultra-short double pulses has gained attraction since the beginning of the 2000s. In the last decade, pulse bursts consisting of multiple pulses with a delay of several 10 ns and less found their way into the area of micromachining of metals, opening up completely new process regimes and allowing an increase in the structuring rates and surface quality of machined samples. Several physical effects such as shielding or re-deposition of material have led to a new understanding of the related machining strategies and processing regimes. Results of both experimental and numerical investigations are placed into context for different time scales during laser processing. This review is dedicated to the fundamental physical phenomena taking place during burst processing and their respective effects on machining results of metals in the ultra-short pulse regime for delays ranging from several 100 fs to several microseconds. Furthermore, technical applications based on these effects are reviewed
Facile FMR1 mRNA structure regulation by interruptions in CGG repeats
RNA metabolism is a major contributor to the pathogenesis of clinical disorders associated with premutation size alleles of the fragile X mental retardation (FMR1) gene. Herein, we determined the structural properties of numerous FMR1 transcripts harboring different numbers of both CGG repeats and AGG interruptions. The stability of hairpins formed by uninterrupted repeat-containing transcripts increased with the lengthening of the repeat tract. Even a single AGG interruption in the repeated sequence dramatically changed the folding of the 5′UTR fragments, typically resulting in branched hairpin structures. Transcripts containing different lengths of CGG repeats, but sharing a common AGG pattern, adopted similar types of secondary structures. We postulate that interruption-dependent structure variants of the FMR1 mRNA contribute to the phenotype diversity, observed in premutation carriers
Rapid Electrochemical Detection of New Delhi Metallo-beta-lactamase Genes To Enable Point-of-Care Testing of Carbapenem-Resistant Enterobacteriaceae
The
alarming rate at which antibiotic resistance is occurring in
human pathogens causes a pressing need for improved diagnostic technologies
aimed at rapid detection and point-of-care testing to support quick
decision making regarding antibiotic therapy and patient management.
Here, we report the successful development of an electrochemical biosensor
to detect <i>bla</i><sub><i>NDM</i></sub>, the
gene encoding the emerging New Delhi metallo-beta-lactamase, using
label-free electrochemical impedance spectroscopy (EIS). The presence
of this gene is of critical concern because organisms harboring <i>bla</i><sub><i>NDM</i></sub> tend to be multiresistant,
leaving very few treatment options. For the EIS assay, we used a <i>bla</i><sub><i>NDM</i></sub>-specific PNA probe that
was designed by applying a new approach that combines <i>in silico</i> probe design and fluorescence-based DNA microarray validation with
electrochemical testing on gold screen-printed electrodes. The assay
was successfully demonstrated for synthetic targets (LOD = 10 nM),
PCR products (LOD = 100 pM), and direct, amplification-free detection
from a <i>bla</i><sub><i>NDM</i></sub>-harboring
plasmid. The biosensor’s specificity, preanalytical requirements,
and performance under ambient conditions were demonstrated and successfully
proved its suitability for further point-of-care test development
Los terceros complejos: lacompetencia de la Jurisdicción Especial para la Paz, Resumen Ejecutivo
This is an executive summary of the policy paper "Los terceros complejos: lacompetencia de la Jurisdicción Especial para la Paz
Los terceros complejos: la competencia de la Jurisdicción Especial para la Paz
This policy paper presents recommendations to the Colombian Special Jurisdiction for Peace regarding the implementation of its competence over third party actors, in particular economic actors, such as corporate directors, business owners, landowners etc., for their role in conflict related crimes
RTE and CTE mRNA export elements synergistically increase expression of unstable, Rev-dependent HIV and SIV mRNAs
Studies of retroviral mRNA export identified two distinct RNA export elements utilizing conserved eukaryotic mRNA export mechanism(s), namely the Constitutive Transport Element (CTE) and the RNA Transport Element (RTE). Although RTE and CTE are potent in nucleocytoplasmic mRNA transport and expression, neither element is as powerful as the Rev-RRE posttranscriptional control. Here, we found that whereas CTE and the up-regulatory mutant RTEm26 alone increase expression from a subgenomic gag and env clones, the combination of these elements led to a several hundred-fold, synergistic increase. The use of the RTEm26-CTE combination is a simple way to increase expression of poorly expressed retroviral genes to levels otherwise only achieved via more cumbersome RNA optimization. The potent RTEm26-CTE element could be useful in lentiviral gene therapy vectors, DNA-based vaccine vectors, and gene transfer studies of other poorly expressed genes
A low density of 0.8 g/cc for the Trojan binary asteroid 617 Patroclus
The Trojan population consists of two swarms of asteroids following the same
orbit as Jupiter and located at the L4 and L5 Lagrange points of the
Jupiter-Sun system (leading and following Jupiter by 60 degrees). The asteroid
617 Patroclus is the only known binary Trojan (Merline et al. 2001). The orbit
of this double system was hitherto unknown. Here we report that the components,
separated by 680 km, move around the system centre of mass, describing roughly
a circular orbit. Using the orbital parameters, combined with thermal
measurements to estimate the size of the components, we derive a very low
density of 0.8 g/cc. The components of Patroclus are therefore very porous or
composed mostly of water ice, suggesting that they could have been formed in
the outer part of the solar system.Comment: 10 pages, 3 figures, 1 tabl
Herschel*-ATLAS: correlations between dust and gas in local submm-selected galaxies
We present an analysis of CO molecular gas tracers in a sample of 500
μ
m-selected
Herschel
-ATLAS galaxies at
z <
0
.
05 (
cz <
14990 km s
−
1
). Using 22
−
500
μ
m photom-
etry from
WISE
,
IRAS
and
Herschel
, with H
i
data from the literature, we investigate
correlations between warm and cold dust, and tracers of the gas in
different phases.
The correlation between global CO(3–2) line fluxes and FIR–submm fl
uxes weakens
with increasing IR wavelength (
λ
&
60
μ
m), as a result of colder dust being less
strongly associated with dense gas. Conversely, CO(2–1) and H
i
line fluxes both ap-
pear to be better correlated with longer wavelengths, suggesting
that cold dust is more
strongly associated with diffuse atomic and molecular gas phases, co
nsistent with it
being at least partially heated by radiation from old stellar populations
. The increased
scatter at long wavelengths implies that sub-millimetre fluxes are a po
orer tracer of
SFR. Fluxes at 22 and 60
μ
m are also better correlated with diffuse gas tracers than
dense CO(3–2), probably due to very-small-grain emission in the diffu
se interstellar
medium, which is not correlated with SFR. The FIR/CO luminosity ratio a
nd the
dust mass/CO luminosity ratio both decrease with increasing luminosit
y, as a result
of either correlations between mass and metallicity (changing CO/H
2
) or between CO
luminosity and excitation [changing CO(3–2)/CO(1–0)].Web of Scienc
- …